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  • 1990-1994  (7,977)
  • 1880-1889  (50)
  • Cell & Developmental Biology  (8,027)
  • 101
    Electronic Resource
    Electronic Resource
    Calmyonemin: A 23 kDa analogue of algal centrin occurring in contractile myonemes of Eudiplodinium maggii (ciliate) (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 169-179 
    Details
    ISSN: 0886-1544
    Keywords: calcium-binding proteins ; myonemes ; centrin ; contractility ; ciliates ; protozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myonemes are bundles of thin filaments (3-6 nm in diameter) which mediate calcium-induced contraction of the whole or only parts of the cell body in a number of protists. In Eudiplodinium maggii, a rumen ciliate which lacks a uniform ciliation of the cell body, myonemes converge toward the bases of apical ciliary zones that can be retracted under stress conditions, entailing immobilization of the cell. An mAB (A69) has been produced that identifies a calciumbinding protein by immunoblot, immunoprecipitation experiments and specifically labels the myonemes in immunoelectron microscopy. Solubility properties, apparent molecular weight (23 kDa) and isoelectric point (4.9) of the myonemal protein, are similar to the values reported for the calcium-modulated contractile protein centrin. Western-blot analysis indicates that the 23 kDa protein crossreacts antigenically with anti-centrin antibodies. In addition, the 23 kDa protein displays calcium-induced changes in both electrophoretic and chromatographic behaviour, and contains calcium-binding domains that conform to the EF-hand structure, as known for centrin. Based on these observations, we conclude that a calcium-binding protein with major similarities to centrin occurs in the myonemes of E. maggii. We postulate that this protein plays an essential role in myonememediated retraction of the ciliature. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270208
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  • 102
    Electronic Resource
    Electronic Resource
    Structural and geometrical constraints on the outer dynein arm in situ (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 299-312 
    Details
    ISSN: 0886-1544
    Keywords: microtubule motors ; dynein ; cilia ; axoneme ; computer modeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study considers the relationship between two structural forms of the 22S dynein arm of Tetrahymena thermophila: the bouquet and the compact arm. The compact arm differs from the bouquet and from other proposed forms (e.g., the “toadstool”) in that the globular domains are situated transversely across the interdoublet gap with one globular subunit, the head, proximal to the adjacent doublet microtubule. The other models place all three globular domains proximal to the neighboring doublet microtubule. When sliding of an isolated axoneme is induced, at least 57% of total attached arms on exposed doublets are in the compact form within dimensions of 24 × 24 × 12 nm, and only about 2% of the arms are bouquets. Toadstools are incompatible with the images seen. Bouquets are not found in regions of the doublet protected by a neighboring doublet. When axonemes with exposed doublets are treated with 0.5 M KCl for 30 min, the compct arms and the dynein heavy (H)-chains disappear, while isolated bouquets and dynein H-chains appear in the medium, suggesting that the compact arms give rise to the bouquets as they are solubilized. The bouquet is the predominant form of isolated 22S dynein molecules, which are found in two apparently enantiomorphic forms, within dimensions 45 × 39 × 13 nm; bouquets attached to doublets have dimensions similar to those of isolated bouquets. Computer modeling indicates that in an intact standard-diameter axoneme, these dimensions are incompatible with the interdoublet volume available for an arm; the bouquet therefore represents an unfolded compact arm. A plausible sequence of changes can be modeled to illustrate the conversion of an attached compact arm to an attached and then free bouquet. The toadstool is probably an artifact that arises after unfolding. Consistent with the conformational difference, H-chains of attached compact arms differ from those of isolated bouquets in their susceptibility to limited proteolysis. These results suggest that the compact arm, rather than the unfolded bouquet or the toadstool, is the functional form of the outer arm in the intact axoneme. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270403
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  • 103
    Electronic Resource
    Electronic Resource
    Localization of tau and other proteins of isolated marginal bands (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 350-360 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; MAPs ; cytoskeleton ; tau ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To determine which proteins were associated with and intrinsic to the marginal band (MB) of microtubules (MTs), we studied protein components of MBs isolated from nucleated erythrocytes by differential detergent solubilization of the membrane skeleton (MS). MBs isolated from dogfish erythrocytes contained major proteins in the tubulin Mr range. A high molecular weight protein of ∼290 kD that bound antibody to syncolin and to heat-stable brain MAPs was present in the whole cytoskeleton. However, most of it was solubilized by the MB isolation medium, together with the MS. Dogfish erythrocyte cytoskeletons and isolated MBs were examined with polyclonal and monoclonal antibodies against mammalian brain tau and chicken erythrocyte tau. As shown by immunofluorescence and immunoblotting, these antibodies bound to proteins in the 50 to 67 kD range, located along the length of isolated MBs. Two-dimensional SDS-PAGE revealed isolated MB proteins of pI ∼6.8 in the same molecular weight range, as well as α- and β-tubulin with pI ∼5.4. Subtilisin or high-salt treatment of isolated MBs resulted in unbundling of MTs, indicating involvement of MAPs. MBs isolated from chicken erythrocyte cytoskeletons also contained tau as shown by antimammalian brain tau immunofluorescence. Both chicken and dogfish isolated MBs also bound phalloidin, but the binding was usually discontinuous and, for any given MB, matched the pattern of anti-syncolin binding. Both syncolin and F-actin were part of the MS remnant remaining after MT disassembly, supporting their assignment to a specialized MS region at the MB/MS interface. In contrast, tau protein appears to be intrinsic to the MB, where it may have an MT stabilizing and bundling function. © 1994 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270407
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  • 104
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280101
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  • 105
    Electronic Resource
    Electronic Resource
    Differences in the effect of Ca2+ on isolated microtubules from cod and cow brain (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 59-68 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; paracrystal ; coiled ribbons ; microtubule-associated proteins ; assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated microtubules from cod and cow brains were compared with respect to their response to calcium ions. The effect of Ca2+ on cod microtubules was found to be temperature dependent. In contrast to cow microtubules, cod microtubules assembled at 18°C. At this temperature the assembly was inhibited by Ca2+ concentrations of 2 mM and higher. This was also found for cow microtubules at 37°C. However, at 30°C there was no effect of 2 mM Ca2+ of the amount of assembly or disassembly of cod microtubules consisting of only tubulin or of tubulin and microtubule-associated proteins (MAPs). The morphology was affected though, since some coiled ribbons formed from tubulin and MAPs. The calcium-binding calmodulin did not alter the effect of calcium on cod microtubules markedly. At higher Ca2+ concentrations (〉4 mM), coiled ribbons were formed from cod tubulin and MAPs, but mainly amorphous aggregates and very few coiled ribbons were formed from cod tubulin alone, indicating that the Ca2+ effect is modulated by cod MAPs. The modulatory effect of cod MAPs was however not species specific, since both cod and cow MAPs had the same effect on cod microtubules, in spite of a different protein composition. A MAP-dependent effect of Ca2+ was also found for cow microtubule proteins. The assembly of pure cow tubulin, as well as that of cow tubulin and MAPs, was inhibited by 2 mM Ca2+. In the presence of 10 and 20 mM Ca2+, pure cow tubulin formed amorphous aggregates, rings, and even paracrystals, while the assembly of cow tubulin and MAPs was inhibited. Our results suggest therefore that the effect of Ca2+ can be moderated by MAPs, but depends on intrinsic properties of the different tubulins. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280106
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  • 106
    Electronic Resource
    Electronic Resource
    Structural and biochemical properties of kinesin heavy chain associated with rat brain mitochondria (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 79-93 
    Details
    ISSN: 0886-1544
    Keywords: kinesin ; brain mitochondria ; motility ; membrane-associated ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Kinesin, a mechanochemical enzyme that translocates membranous organelles, was initially identified and purified from soluble extracts from vertebrate brains. However, immunocytochemical and morphological approaches have demonstrated that kinesin could be associated to intracellular membranous organelles. We used an antibody raised against the head portion of the Drosophila kinesin heavy chain to reveal the presence of this protein in membranous organelles from rat brain. By using differential centrifugation and immunoblotting we observed a 116 kDa protein that crossreacts with this antibody in microsomes, synaptic vesicles, and mitochondria. This protein could be extracted from mitochondria with low salt concentrations or ATP. The 116 kDa solubilized protein has been identified as conventional kinesin based on limited sequence analysis. We also show that a polyclonal antibody raised against mitochondria-associated kinesin recognizes soluble bovine brain kinesin. The soluble and mitochondrial membrane-associated kinesins show a different isoform pattern. These results are consistent with the idea that kinesin exists as multiple isoforms that might be differentially distributed within the cell. In addition digitonin fractionation of mitochondria combined with KI extraction revealed that kinesin is a peripheral protein, preferentially located in a cholesterol-free outer membrane domain; this domain has the features of contact points between the mitochondrial outer and inner membranes. The significance of these observations on the functional regulation of the mitochondria-associated kinesin is discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280108
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  • 107
    Electronic Resource
    Electronic Resource
    Intact alpha-actinin molecules are needed for both the assembly of actin into the tails and the locomotion of Listeria monocytogenes inside infected cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 97-107 
    Details
    ISSN: 0886-1544
    Keywords: Listeria ; actin ; alpha-actinin ; vinculin ; talin ; filopodia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: After the infectious bacterium, Listeria monocytogenes, is phagocytosed by a host cell, it leaves the lysosome and recruits the host cell's cytoskeletal proteins to assemble a stationary tail composed primarily of actin filaments cross-linked with alpha-actinin. The continual recruitment of contractile proteins to the interface between the bacterium and the tail accompanies the propulsion of the bacterium ahead of the elongating tail. When a bacterium contacts the host cell membrane, it pushes out the membrane into an undulating tubular structure or filopodium that envelops the bacterium at the tip with the tail of cytoskeletal proteins behind it. Previous work has demonstrated that alpha-actinin can be cleaved into two proteolytic fragments whose microinjection into cells interferes with stress fiber integrity. Microinjection of the 53 kD alpha-actinin fragment into cells infected with Listeria monocytogenes, induces the loss of tails from bacteria and causes the bacteria to become stationary. Infected cells that possess filopodia when injected with the 53 kD fragment lose their filopodia. These results indicate that intact alpha-actinin molecules play an important role in the intracellular motility of Listeria, presumably by stabilizing the actin fibers in the stationary tails that are required for the bacteria to move forward. Fluorescently labeled vinculin associated with the tails when it was injected into infected cells. Talin antibody staining indicated that this protein, also, is present in the tails. These observations suggest that the tails share properties of attachment plaques normally present in the host cells. This model would explain the ability of the bacterium (1) to move within the cytoplasm and (2) to push out the surface of the cell to form a filopodium. The attachment plaque proteins, alpha-actinin, talin, and vinculin, may bind and stabilize the actin filaments as they polymerize behind the bacteria and additionally could also enable the tails to bind to the cell membrane in the filopodia. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280202
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  • 108
    Electronic Resource
    Electronic Resource
    Clustered acetylcholine receptors have two levels of organization in Xenopus muscle cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 179-193 
    Details
    ISSN: 0886-1544
    Keywords: acetylcholine receptor ; deep-etch replication ; sarcolemma ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We studied the organization of acetylcholine receptor (AChR) clusters by shearing cultured Xenopus muscle cells with a stream of buffer, and preparing rotary replicas of the exposed cytoplasmic surface of the sarcolemma. AChR clusters contained numerous particles that protruded from the sarcolemma and formed an irregular array composed of discrete aggregates. AChR were located within these particle aggregates, as shown by comparison of the replicas to labeling by fluorescent α-bungarotoxin, and by immunogold cytochemistry with antibodies specific for the receptor. The aggregates were cross-linked by a dense network of 7 nm filaments that replicated with the banded pattern characteristic of actin microfilaments. The organization of receptors into the small aggregates was independent of the organization of these aggregates into clusters, as alkaline extraction removed the microfilament network and disrupted the irregular array of particle aggregates, but did not disperse individual receptors from the aggregates. We conclude that two levels of interactions organize AChR clusters in Xenopus muscle cells: short-range interactions that assemble individual AChR into small aggregates, and long-range interactions, perhaps mediated by actin microfilaments, that anchor the aggregates into larger clusters. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280209
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  • 109
    Electronic Resource
    Electronic Resource
    Fluorescence studies of spectrin and its subunits (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 72-81 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; intrinsic fluorescence ; spectrin elasticity ; fluorescence quenching ; spectrin α chain ; spectrin β chain ; membrane skeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To better understand the solution structure of spectrin, the environments of its tryptophan residues have been examined by fluorescence spectroscopy. The spectra and the extent of quenching by several quenching agents have been determined for intact spectrin and its α and β subunits. The arsenal of quenchers used in the study represented both hydrophilic and hydrophobic species including anionic, cationic and neutral compounds. Effects on spectrin fluorescence of ethanol and ionic strength, which extend and/or rigidify spectrin, and of glycerol, which is commonly used in electron microscopy of the protein, have also been assessed in the presence and absence of quenchers. Most of the tryptophans of spectrin are either internally quenched or are sequestered, hindering the approach of hydrophilic quenching agents. Both the spectral shape and the extent of quenching by acrylamide indicate that some tryptophans of the β subunit are slightly more exposed in the isolated chain than in the dimer. Similar effects on spectra and on quenching of the intact dimer and of the isolated β chain are seen when the ionic strength is reduced. Ethanol and glycerol reduce spectrin tryptophan accessibility to 2-p-toluidinyl napthalene-6-sulfonic acid (TNS). It therefore appears that low ionic strength, α-β association and neutral solute (or lowered dielectric constant) all induce a similar, but modest conformational change in the domain structure. The extent of TNS binding is not increased by lowering the ionic strength, suggesting that the expansion and/or stiffening of the molecule in low electrolyte solutions does not involve exposure of significant numbers of hydrophobic sites. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290107
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  • 110
    Electronic Resource
    Electronic Resource
    Effects of 6-dimethylaminopurine on the length of the cell cycle and on the state of phosphorylation of putative intermediate filament proteins in sea urchin embryos (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 131-140 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; phosphorylation ; sea urchin embryos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of 6-dimethylaminopurine (6-DMAP) on the length of the cell cycle and on the state of phosphorylation of a putative intermediate filament protein, p117, have been studied in sea urchin embryos. Embryos were transferred into sea water containing 600 μM 6-DMAP at 0.5, 2 or 5 min after insemination, and incubated for 30 or 90 min. The effects of 6-DMAP on cell cycle length were studied by determining the time required for completion of mitosis upon return of the embryos in normal sea water. In all instances, except for the embryos transferred 0.5 min after insemination (AI) and incubated for 30 min, the duration of the M phase was shortened compared to controls, being faster in the embryos incubated for 90 minutes compared to the 30 min incubation period. However, embryos transferred 0.5 min AI have a longer M-phase than those transferred 2 minutes or later after fertilization, suggesting that between 0.5 and 2 min after fertilization, critical phosphorylating events occur which affect the commitment of the cells to enter M-phase.To study the pattern of p117 phosphorylation during the cell cycle, the eggs were transferred 2 minutes after fertilization in presence of 600 μM 6-DMAP and with 200 μCi/ml of 32P-orthophosphate. Analyses of 32P-labelled proteins after exposure of SDS-PAGE gels and their corresponding blots suggested that phosphorylation of p117 greatly increases at the time of pronuclear fusion, and then declines slightly at prophase-metaphase. This decrease is markedly enhanced when the cells are treated with 6-DMAP during metaphase in order to induce a premature breakdown of the mitotic apparatus. A causal link is suggested between the level of phosphorylation of p117 and its state of assembly. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290205
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  • 111
    Electronic Resource
    Electronic Resource
    Stimulation of the ATP-dependent interaction between actin and myosin by a myosin-binding fragment of smooth muscle caldesmon (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 250-258 
    Details
    ISSN: 0886-1544
    Keywords: binding of caldesmon to myosin ; actin-activated ATPase activity of myosin ; actin-myosin interaction with in vitro motility assay ; myosin-binding domain of caldesmon ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We reported previously that smooth muscle caldesmon stimulates the ATP-de-pendent interaction between actin and phosphorylated smooth muscle myosin, as monitored by ATPase measurment and in vitro motility assay. Furthermore, this effect changes from stimulatory to inhibitory with increasing concentrations of caldesmon [Ishikawa et al., 1991: J. Biol. Chem. 266:21784-21790]. The N-terminal (myosin-binding) fragment and the C-terminal (actin-binding) fragment were purified from digests of caldesmon. The effects of the myosin-binding fragment and the actin-binding fragment on the interaction were stimulatory and inhibitory, respectively, indicating that stimulatory and inhibitory domains are localized in the myosin-binding domain and actin-binding domain of caldesmon, respectively. The effect of the myosin-binding fragment on the interaction was exclusively stimulatory when the interaction was challenged by caldesmon, both at lower and higher concentrations. However, the actin-binding fragment had no effect on the interaction at lower concentrations and inhibited the interaction at higher concentrations. Thus, the stimulatory effect of caldesmon that is observed at lower concentrations can be explained by the hypothesis that the stimulatory effect of the myosin-binding domain predominates over the inhibitory effect of the actin-binding domain when the concentration of caldesmon is low. With uncleaved caldesmon, we also emphasized the role of the myosin-binding domain in the stimulation as follows; the stimulatory effect of caldesmon became obscured when binding of caldesmon to myosin was competed by the exogenous caldesmon-binding fragment of myosin. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290308
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  • 112
    Electronic Resource
    Electronic Resource
    Novel 130-kDa rat liver myosin-1 will translocate actin filaments (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 41-48 
    Details
    ISSN: 0886-1544
    Keywords: myosin-1 ; motility ; F-actin ; liver ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have recently purified and characterized from rat liver, polypeptides of 110-kDa and 130-kDa which possess several characteristics of myosin-1 [Coluccio and Conaty: Cell Motil. Cytoskeleton 24:189-199, 1993]. What roles these myosin-1 molecules play in hepatocytes is not yet defined. One hypothesis is that they are involved in either intracellular transport or locomotion. As a first step in establishing their function, we have investigated whether these molecules are capable of supporting motility in vitro. Our results clearly demonstrate that the isolated 130-kDa-calmodulin complex will translocate filaments at a rate of 0.03-0.05 μ/sec; motility is inhibited in free calcium ion concentrations above 0.1 μM. This inhibition is reversed with the addition of exogenous calmodulin. These results provide supporting evidence of a motile role for the 130-kDa-calmodulin complex in vivo. This is the first demonstration that in higher eukaryotes, myosin-1 from a tissue other than intestine will support motility. Partial peptide sequence analysis indicates that the 130-kDa polypeptide resembles the recently described myr 1 [Ruppert et al.: J. Cell Biol. 120:1393-1403, 1993] or MM1α [Sherr et al.: J. Cell Biol. 1405-1416, 1993] gene product. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270105
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  • 113
    Electronic Resource
    Electronic Resource
    Microtubules with altered assembly kinetics have a decreased rate of kinesin-based transport (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 79-87 
    Details
    ISSN: 0886-1544
    Keywords: microtubule transport ; microtubules ; 2,5-hexanedione ; glutaraldehyde ; kinesin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules treated with the γ-diketone 2,5-hexanedione (2,5-HD) have altered assembly behavior characterized by precocious nucleation and rapid elongation. By measuring the rate of microtubule transport, we have examined the potential functional significance of this 2,5-HD-induced microtubule modification. 2,5-HD-treated microtubules were transported at only 70% of the rate of control microtubules in a simple kinesin-based motility assay on glass coverslips using video and computer enhanced differential interference contrast microscopy. Since 2,5-HD is capable of forming both pyrrole adducts and crosslinks with tubulin, the contributions of pyrrole formation and crosslinking to slowed microtubule transport were determined. 3-Acetyl-2,5-hexanedione (AcHD), a pyrrole forming, non-crosslinking congener of 2,5-HD which does not alter microtubule assembly, did not produce slowed microtubule transport as occurs with 2,5-HD. However, glutaraldehyde, a pyrrole-independent crosslinking agent which alters microtubule assembly in the same way as 2,5-HD, slowed microtubule transport. These results indicate that a 2,5-HD-induced microtubule modification, possibly a crosslink-related conformational change, produces both an alteration in the kinetics of assembly and an alteration in the microtubule-motor interaction. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270109
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  • 114
    Electronic Resource
    Electronic Resource
    Nuclear dynamics of parthenogenesis of bovine oocytes matured in vitro for 20 and 40 hours and activated with combined ethanol and cycloheximide treatment (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 61-68 
    Details
    ISSN: 1040-452X
    Keywords: Aging oocytes ; Pronuclei ; Cattle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Bovine oocytes matured in vitro (IVM) for 20 hr vs. 40 hr were treated for activation with 7% ethanol in Dulbecco's phosphate-buffered saline for 5 min followed by incubation in M199 + 7.5% fetal calf serum containing cycloheximide (10 μg/ml). TreatedIVM oocytes and the controls (no ethanol and cycloheximide exposures) were fixed after 0, 1, 2, 3, 4, 5, 7, 10, and 20 hr of incubation and stained 24 hr later with 1% acetoorcein to examine nuclear events. Different stages of nuclear development of the activated oocytes were identified on the basis of nuclear and chromosomal morphology. Pronuclear development was classified into four stages (PN I, II, III, and IV) according to pronuclear progression in chromatin decondensation, nucleoplasm appearance, and nuclear size. The results demonstrated that the combined activation treatment effectively drove the IVM oocytes, both young (20 hr) and aging (40 hr), out of metaphase arrest. The activation rates for young oocytes examined immediately after 0, 1, 2, 3, 4, 5, 7, 10, and 20 hr of incubation with cycloheximide were, respectively, 7%, 24%, 77%, 96%, 92%, 97%, 98%, 93%, and 98%. For aging oocytes (40 hr) the corresponding activation values at the same time intervals were 6%, 84%, 100%, 100%, 100%, 100%, 98%, 100%, and 100%, respectively. These values were significantly higher than those for the corresponding controls. The activated aging oocytes achieved peak activation response more rapidly than did young oocytes. In addition, nuclear events in aging oocytes proceeded faster than those in young ones. Spontaneous activation rates of the aging oocytes were also higher (6-57%) than those of the young ones (0-14%). © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370109
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  • 115
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    Translational activity of mouse protamine 1 messenger ribonucleoprotein particles in the reticulocyte and wheat germ cell-free translation systems (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 12-20 
    Details
    ISSN: 1040-452X
    Keywords: Spermatids ; Translational regulation ; mRNPs ; Translational initiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Protamine 1 mRNAs are inactivated by a block to the initiation of translation in early spermatids and are translationally active in late spermatids in mice. To determine whether translation of protamine 1 mRNAs is inhibited by a protein repressor, the translational activity of ribonucleoprotein particles and deproteinized RNAs were compared in the reticulocyte and wheat germ cell-free translation lysates. To isolate RNPs, cytoplasmic extracts of total testes were fractionated by large-pore gel filtration chromatography. Ribonucleoprotein particles in the excluded fractions stimulated synthesis of radiolabeled translation products for protamine 1 about twofold less effectively than deproteinized RNAs in the reticulocyte lysate, but were inactive in the wheat germ lysate. The ability of translationally repressed protamine 1 ribonucleoprotein particles to form initiation complexes with 80S ribosomes in the reticulocyte lysate was also measured. Protamine 1 ribonucleoprotein particles isolated by gel filtration and in unfractionated cytoplasmic extracts of early spermatids were nearly as active in forming initiation complexes as deproteinized mRNAs. The isolation of ribonucleoprotein particles in buffers of varying ionic strength, protease inhibitors, and several other variables had no major effect on the ability of protamine 1 ribonucleoprotein particles to form initiation complexes in the reticulocyte lysate. These results can be explained by artifacts in the isolation or assay of ribonucleoprotein particles or by postulating that protamine 1 mRNAs are inactivated by a mechanism that does not involve protein repressors, such as sequestration. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370103
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    In vitro-cultured bovine granulosa and oviductal cells secrete sperm motility-maintaining factor(s) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 54-60 
    Details
    ISSN: 1040-452X
    Keywords: Cattle ; Cumulus oophorus ; Folicular fluid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Since bovine cumulus oophorous and oviductual cell cultures are known to support and maintain frozen-thawed bovine sperm viability and motility for extended time periods, we investigated whether granulosa cell (GC)- and oviductual cell (OC)-conditioned media have similar effects. GC and OC were cultured for 3 days in TCM-199 medium supplemented with 10% fetal calf serum. At that time, the supernatant was discarded from GC and the monolayers were covered with Sp-TALP medium containing 6 mg/ml bovine serum albumin, while the OC were recovered by centrifugation and transferred to culture bottles containing Sp-TALP. Two days later, GC-conditioned and OC-conditioned Sp-TALP were recovered and dialyzed, and their retentates were lyophilized. Bovine follicular fluid (BFF) was also dialyzed, and its retentate was lyophilized. When sperm were incubated in GC- or OC-conditioned media, motility remained above 62% and 42% at 6 hr and 30 hr, respectively, and motility was higher than that of the control both at 6 hr (39%; P 〈 0.001) and at 30 hr (9%; P 〈 0.0001). Similarly, when sperm were incubated in the lyophilized retentates of GC- and OC-conditioned media and in BFF at a dose of 0.1, 0.5, or 1.0 mg/ml, the motility rates were higher both at 6 hr (P 〈 0.05) and at 30 hr (P 〈 0.01) compared to the control. The increase in motility was dose dependent; a 1.0 mg/ml dose improved (P 〈 0.05) motility compared to a 0.1 mg mg/ml dose. Heat treatment of the retentates of GC, OC, and BFF at 55°C for 30 min did not destroy their ability to support and maintain motility. However, heating at 100°C for 5 min destroyed their ability to support motility. Molecular sieving of retentates on Sephancryl S-300 yielded fractions that were highly effective (P 〈 0.01) in enhancing and maintaining motility compared to the other fractions. In conclusion, GC and OC secrete nondialyzable, heat-labile factor(s), which support and maintain sperm viability and motility for up to 30 hr. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370108
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    Chromatin condensation in hamster sperm: A flow cytometric investigation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 93-98 
    Details
    ISSN: 1040-452X
    Keywords: Chromatin condensation ; DNA packaging ; Spermatozoa ; Hamster ; Acridine orange ; Flow cytometry ; Bromobimane ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In this study we have used acridine orange staining, as described by Evenson (1990), to follow changes in DNA packaging as they occur in hamster spermatozoa which have left the testis and are undergoing maturation in the epididymis. Measurement of the green and red fluorescent intensities of hamster sperm nuclei by flow cytometry demonstrated a decrease in acridine orange binding to DNA as sperm made their way from proximal corpus epididymis to the vas deferens. Using sperm from the cauda epididymis of the mature hamster as the standard, a method was developed for estimating the % of cells in a given sample that have matured with regard to DNA packaging. Staining with bromobimane was used to determine the extent of sulfhydryl oxidation in the nuclei. It was seen that sulfhydryl oxidation occurred mainly in the cauda epididymis whereas another process in chromatin condensation occurred earlier, during sperm passage through the caput epididymis. This earlier process could be mimicked by incubating sperm nuclei with alkaline phosphatase, suggesting that it consists of removal of phosphate in protamine. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370113
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    Contractile proteins and nonerythroid spectrin in oogenesis of Xenopus laevis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 99-109 
    Details
    ISSN: 1040-452X
    Keywords: Oocyte growth ; Oocyte maturation ; Egg ; Actin ; Myosin ; Spectrin ; Animal-vegetal polarity ; Cortex ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The distribution of contractile proteins, actin and myosin, and an actin-binding protein, spectrin, was studied in oogenesis of Xenopus laevis. These proteins are present in oocytes already at the previtellogenic stages, which are characterized by their diffuse distribution. The localization of proteins changed with the beginning of vitellogenesis. At all vitellogenic stages, including the fully grown oocyte, animal-vegetal differences were noted in localization of actin and myosin: in the animal hemisphere they appear as fibrillar-like structures, while in the vegetal one they are localized around the yolk platelets. By the end of the oocyte's growth, a cortical gradient appeared: predominant localization of actin and myosin in the cortical area. As the oocyte maturation proceeded, the distribution of actin and myosin again became diffuse and nonuniform, so that a cortical gradient appears. At the beginning of vitellogenesis spectrin is distributed as a network all over the ooplasm, while in the fully grown oocyte it is localized mostly in teh subcortical area of the animal hemisphere and, as individual inclusions, in other regions of the oocyte. No spectrin is found by the end of maturation. Actin, myosin, and spectrin are also present in the oocyte's nuclei. Changes in the distribution of contractile proteins and spectrin during oocyte maturation are discussed with respect to the development of cortical contractility, as well as to the changes in spatial distribution of yolk platelets and regional sensitivity of the maturing oocyte to cytochalasin B. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370114
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    Characterization of a cell surface glycoprotein associated with maturation of rat spermatozoa (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 110-119 
    Details
    ISSN: 1040-452X
    Keywords: Sperm ; Glycoprotein ; GPI ; Maturation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The principal galactose oxidase/NaB[3H]4-labeled membrane protein of rat caudal epididymal spermatozoa was isolated by hydrophobic interaction chromatography. The protein is released from the membrane by the action of phosphatidylinositol specific phospholipase C, and thereby its properties are transformed from those of a protein anchored to the hydrophobic membrane to those of a hydrophilic solution protein. Because it is the only membrane-associated protein released by the enzyme which did not absorb to a propylaspartate resin, a simple, single step purification procedure was devised.Although the amino terminus of the protein is blocked to Edman degradation, the majority of the protein structure was determined from a series of tryptic peptides and from limited acid hydrolysis. Approximately 65% of the protein mass is carbohydrate which is primarily attached through O-glycosidic bonds to the 18 threonines. The molecular weight of the glycoprotein was estimated to be 16,600, considerably smaller than the Mr = 26,000 to 37,000 previously determined by gel electrophoresis. The anomalous electrophoretic behavior is undoubtedly due to the large percentage of carbohydrate. The distribution of carbohydrate on the protein side chains suggests the protein may form a positively charged, specialized scaffolding for the presentation of the carbohydrate moieties. Because the appearance of the ability to label the protein with galactose oxidase is correlated with sperm maturation in the epididymis, the glycoprotein structures may be an important componetn in the fertilization process. The combination of linkage by glycosylphosphatidylinositol and low molecular weight mucin-like structure indicates this may be a member of a new class of membrane proteins. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370115
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370201
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    Ten years plant molecular biology, edited by Robert Schilperoort and Leon Dure, Kluwer Academic Publishers, Dordrecht, NL, 1992, 199 pp, $65 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 120-120 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370120
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    Relationship between sperm nucleus remodelling and cell cycle progression of fragments of mouse parthenogenotes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 146-156 
    Details
    ISSN: 1040-452X
    Keywords: Fertilization ; Sperm Remodelling ; Oocyte Fragments ; Cybrids ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Nucleate and anucleate fragments of parthenogenetically activated mouse oocytes, as well as cybrids obtained by fusion of anucleate fragments (cytoplasts) of maturing and activated matured oocytes were fertilized at different time after activation. Remodelling of the sperm nucleus was studied by electron microscopy at 1.5 and 3 h after fertilization and, in addition, at 14 h in cybrids. Results show that (1) the nuclear envelope of the sperm nucleus can break down when the insemination takes place after the end of M-phase, but the capacity of the parthenote cytoplasm to remodel the sperm nucleus is restricted in time. (2) Male chromatin can decondense within the old, unbroken nuclear envelope, but in such cases formation of a male pronucleus, one of the two nuclei of zygote possessing inactive nucleoli, is never observed. © 1994 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370205
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    Major human epididymis-specific gene product, HE3, is the first representative of a novel gene family (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 130-137 
    Details
    ISSN: 1040-452X
    Keywords: Human Epididymis ; HE genes ; Gene family ; Pseudogene ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Differential screening of a human epididymal cDNA library led to the isolation and characterization of a major epididymis-specific cDNA clone family, referred to as HE3. More detailed sequence and PCR analysis identified two different but homologous gene transcripts, HE3α and HE3β. The former represents an mRNA of ca. 1 kb, encoding a putative small secretory polypeptide of 14903 MW. The HE3β transcript was only found as incomplete 3′ fragments. Analysis of human genomic DNA by Southern blotting suggested the presence in the human genome of at least three independent HE3-related genes. Isolation of genomic clones for the HE3α gene showed this to contain a single intron of 1.4 kb in the 5′ noncoding region. Although genomic clones corresponding to HE3β could not be found, a third highly homologous gene, HE3γ, was identified as a potential pseudogene. Neither nucleotide nor encoded amino acid sequences of the HE3 gene family are related to any other known sequence in the central databases, and thus represents a novel human gene family, with at least three nonallelic members. Northern hybridization analysis showed that HE3 gene products are specifically expressed in the human epididymis, and not in any other tissue examined. Furthermore, except for the pig, no other nonprimate species has been identified to express homologous sequences in the epididymis. RNase protection assays showed that both the HE3α and HE3β, but not the HE3γ genes, are expressed in the human epididymis. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370203
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    Low-affinity nerve growth factor receptor is expressed during testicular morphogenesis and in germ cells at specific stages of spermatogenesis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 157-166 
    Details
    ISSN: 1040-452X
    Keywords: Neurotrophin receptors ; Testis development ; Spermatogenesis ; Male germ cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Nerve growth factor (NGF) is essential for neuronal development and differentiation. Recent reports have shown that its low-affinity receptor (LNGFR) is expressed and developmentally regulated in a broad range of embryonic and adult tissues outside the nervous system, although the functions of the receptor in such tissues remain unknown. Recently, NGF and LNGFR have been detected in adult mouse, rat, and human testis.The results of the present work demonstrate that LNGFR is expressed much before the onset of spermatogenesis in both mouse and rat testis. In situ hybridization shows that the mRNA for LNGFR is expressed in the peritubular cells of the embryonic mouse testis. Immunohistochemical analysis of the rat testis shows LNGFR-expressing cells to be scattered in the intertubular compartment in the embryonic testis, and to become organized in a cellular layer that surrounds myoid cells of the seminiferous tubules during postnatal development. Furthermore, in peripuberal and adult mouse and rat testis we have identified the expression of an abundant and shorter mRNA of 3.2 kb that cross hybridizes to the low-affinity NGF receptor transcript (3.7 kb). This shorter mRNA species, which appears at the beginning of spermatogenesis in the adult, has been identified by in situ hybridization and by Northern blot with RNA isolated from homogeneous populations of meiotic germ cells to be expressed by pachytene spermatocytes and round spermatids. Our results suggest a complex developmental role for LNGFR during testicular morphogenesis and identify the expression, at specific stages of spermatogenesis, of a new germ cell - specific transcript homologous to the receptor RNA. © 1994 Wiiey-Liss, inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370206
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    Immunolocalization of proacrosin/acrosin in rabbit sperm during acrosome reaction and in spermatozoa recovered from the perivitelline space (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 216-222 
    Details
    ISSN: 1040-452X
    Keywords: Acrosin ; Acrosome reaction ; Rabbit sperm ; Perivitelline spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The participation of acrosin in mammalian sperm penetration through the zona pellucida has been amply debated. In this paper we report the immunolocalization - by silver enhanced immunogold technique using ACRO-8C10 monoclonal antibody to human acrosin - of proacrosin/acrosin on ejaculated rabbit spermatozoa incubated in vitro in a capacitating medium and on spermatozoa recovered from the perivitelline space. After incubation in a capacitating medium, four different patterns were observed: (1) no labeling on acrosome intact spermatozoa; (2) labeling on the rim of the head; (3) labeling on the whole acrosome area; and (4) no labeling on acrosome reacted spermatozoa. At the start of incubation, spermatozoa with pattern 1 were the most abundant, whereas at the end of the 32 h incubation period, patterns 2 and 3 were the most frequent. On the other hand, 625 perivitelline spermatozoa were recovered from 17 fertilized rabbit eggs, of which 26% were labeled with the anti-acrosin monoclonal antibody ACRO-8C10 in two different areas: (1) only on the equatorial region; and (2) only on the postacrosomal area. These results are consistent with the idea that proacrosin/acrosin remains associated to the acrosome reacted spermatozoa for long periods of time, and that proacrosin/acrosin associated to perivitelline spermatozoa could be responsible for the second penetration of fresh rabbit eggs by perivitelline spermatozoa. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370213
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    Effects of cryopreservation on the intracellular calcium concentration of human spermatozoa and its response to progesterone (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 241-246 
    Details
    ISSN: 1040-452X
    Keywords: Spermatozoa ; semen preservation ; Cytosolic calcium ; Fura-2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The intracellular free calcium concentration [Ca2+]i of sperm from 23 ejaculates was measured before and after cryopreservation using the fluorescent probe Fura-2. Spermatozoa were treated with 3.18 μM progesterone so that the regulation of [Ca2+]i in a dynamic situation could be studied. [Ca2+]i (nM) was 290 ± 13 in fresh spermatozoa vs. 550 ± 26 in cryopreserved samples (mean ± S.E.M. P 〈 0.0001 paired t-test). Progesterone at a dose of 3.18 μM stimulated a large and rapid increase in [Ca2+]i to a peak value 〉 1 μM after 10-20 seconds. [Ca2+]i then declined to a slightly raised basal level over the next 30-40 seconds. This phenomenon occurred in all the fresh samples, but about half the frozen thawed samples failed to respond. The peak [Ca2+] attained by frozen samples which did respond after the addition of progesterone was similar to that observed with fresh sperm. The calcium channel blocker verapamil (200 μM) completely inhibited the transient rise in [Ca2+]i produced by progesterone, but 100 μM verapamil had only a partial effect. We conclude that (1) cryopreservation causes a substantial elevation of the [Ca2+]i in human spermatozoa and (2) damage to the plasma membrane during cryopreservation may result in the loss of the progesterone receptor. Both factors may contribute to the loss of fertility after cryopreservation. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370216
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    Synthesis and processing of mammalian protamines and transition proteins (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 255-263 
    Details
    ISSN: 1040-452X
    Keywords: Phosphorylation ; Chromatin condensation ; Testis ; DNA binding proteins ; Seminiferous tubules ; Sonication-resistant nuclei ; mP1 ; Pre-mP2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mouse and rat seminiferous tubule fragment cultures were used to examine synthesis and processing of mammalian protamines and transition proteins. The tubule fragments were incubated with [3H]-arginine, [3H]-histidine, [35S]-cysteine, or [32P]-PO4, and radiolabeled proteins were analyzed by acid/urea polyacrylamide gel electrophoresis and fluorography or autoradiography. Newly synthesized protamines were recovered from sonication-resistant nuclei (SRN) and could not be detected in cytoplasmic fractions, indicating that protamines are deposited into nuclei immediately after synthesis. Newly synthesized mouse protamine 1 (mP1) and the precursor to mouse protamine 2 (pre-mP2) migrated more slowly during electrophoresis than their predominant testicular forms, identified by staining with Coomassie blue R-250. Within 1 hour of synthesis, the electrophoretic mobilities of mP1 and pre-mP2 increased to match those of their predominant forms. These changes are consistent with initial charge-neutralizing modifications of the newly synthesized protamines, followed by removal of at least some of the modifying ligands, to unmask protamine basicity. Steady-state phosphorylation rates were high for rat protamine 1 (rP1) and were independent of phosphate content; both rP1 molecules of low and high phosphate content were rapidly phosphorylated. Pre-mP2-3, a major processing intermediate derived by proteolysis of pre-mP2, was also rapidly phosphorylated. Like the protamines, transition protein 2 (TP2) was rapidly phosphorylated and increased in electrophoretic mobility soon after synthesis. In contrast, transition protein 1 (TP1) was not phosphorylated and did not exhibit multiple electrophoretic forms. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080370303
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    Functions of milk protein gene 5′ flanking regions on human growth hormone gene (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 276-283 
    Details
    ISSN: 1040-452X
    Keywords: Milk proteins ; Mammary gland ; PCR ; Microinjection ; RIA ; Expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fragments containing 5′ flanking regions of four bovine milk protein genes - alpha lactalbumin (bαLA), alpha S1 casein (bαS1CN), beta casein (bβCN), kappa casein (bkCN) - and mouse whey acidic protein (mWAP) gene were prepared by PCR and ligated to human growth hormone (hGH) gene. These recombinant DNAs were microinjected into rat embryos to produce transgenic rats, and the functions of the 5′ regions to direct secretion of hGH in the milk were tested. Although milk was obtained only in 5 of 19 mWAP/hGH rat lines, more than two-thirds of the rats carrying the other four DNAs produced milk. More than 80% of the lactated rats carrying bαLA/, bβCN/, and mWAP/hGH, and 33% of the laclated bαS1CN/hGH rats secreted detectable amounts of hGH (〉 0.05 μg/ml) in the milk. In some rats, the hGH concentrations in the milk were comparable to or more than that of the corresponding milk protein in bovine milk. The ranges of hGH concentrations in the milk of bαLA/, bβCN/, bαS1CN/, and mWAP/hGH rats were 1.13-4,360 μg/ml, 0.11-10,900 μg/ml, 86.8-6,480 μg/ml, and 6.87-151 μg/ml, respectively. HGH was also detected in the sera of these rats, and some abnormalities of growth and reproduction were observed. All but one virgin mWAP/hGH rat secreted up to 0.0722 μg/ml of hGH in the serum, and more than half of them showed abnormal fat accumulations at their abdomen. None of the bαCN/hGH rats secreted detectable amount of hGH into their milk, whereas 8 of the 11 lines secreted hGH into their sera. For the production of hGH in transgenic rat milk, the 5′ region of bαS1CN was shown most suitable, because the bαS1CN/hGH rat secreted 〉 6,000 μg/ml of hGH into the milk and could be reproduced. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080370306
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    Sperm nuclear chromatin transformations in somatic cell-free extracts (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 305-317 
    Details
    ISSN: 1040-452X
    Keywords: HeLa extracts ; Chromatin decondensation ; Remodelling ; Recondensation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: HeLa cell extracts induced decondensation of lysolecithin permeabilized Xenopus, pig, and human sperm chromatin; decondensation began almost immediately on incubation in the extract and was completed within 10-20 min. The average enlargements of human and pig sperm nuclei were 15-fold and 3-fold, respectively. The structural organization of pig and human sperm chromatin was significantly differnt. Decondensation was differentially inhibited by Mg++ and polyamines; inhibition was least for Xenopus and most for pig sperm nuclei. The nuclear membrane was disintegrated on chromatin dispersion, whereas the nuclei which failed to decondense exhibited distinct nuclear envelopes. The decondensing factors were stable at 65°C for 15 min. The dispersed chromatin was remodelled to somatic nucleosomal structures within 60 min. The remodelled chromatin could be recondensed to chromosome-like structures, when incubated further in extracts from mitosis arrested HeLa cells. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370310
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370401
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    Transcription of circular and noncircular forms of Sry in mouse testes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 370-381 
    Details
    ISSN: 1040-452X
    Keywords: Sex determination ; Sex determining region Y ; Postmeiotic expression ; HMG box containing proteins ; Interstitial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Although its expression in adult testis was immediately apparent, the role for Sry (sex determining region, Y) in testicular function remains elusive. We have performed transcriptional studies in an effort to elucidate potential roles of Sry by studying the time and location of its transcription in mouse testes. Northern analyses and more sensitive nuclease protection assays detected transcripts in 28-day-old testes and beyond. The highly sensitive technique of reverse transcription polymerase chain reaction (RTPCR) could not detect Sry expression in 14-day testes when primers for the most conserved portion of the gene, the high mobility group (HMG) box, were used, but primers for the circular form detected Sry transcription at all postnatal stages studied. The same HMG box primers were able to detect expression of Sry in XX, Sxra or Sxrb testes. This suggested that Sry is expressed in cells other than germ cells, which was confirmed with studies on fractionated cells - RTPCR detected transcription of Sry in the highly pure interstitial cell fraction. However, Leydig cells and a Leydig cell tumor were negative for Sry expression. We performed in situ studies in an attempt to localize the expression of Sry in the testes. Abundant expression of an Sry cross-hybridizing transcript was found in spermatogonia, in early spermatocytes, and in some interstitial cells with antisense probes to the HMG box or a more specific, 3′ region, whereas the sense probe gave little or no hybridization. It is probable that the circular transcripts, which are seen in reverse transcriptase positive (RT+) and RT- reactions by PCR because of the RT activity of Taq polymerase, are responsible for the hybridization seen in spermatogonia and spermatocytes, whereas linear and circular forms are detected later. Thus Sry is expressed in pre- and postmeiotic germ cells and in somatic cells of the testes. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370403
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    Expression of insulin-like growth factors I and II in conceptuses from normal and diabetic mice (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 382-390 
    Details
    ISSN: 1040-452X
    Keywords: Insulin-like growth factors ; Diabetes ; Embryos ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Insulin-like growth factors (IGF-I and IGF-II) play an important regulatory role in fetal growth and development. Alterations in expression of these growth factors may result in developmental abnormalities, macrosomia, and intrauterine growth retardation, which occur with a higher incidence in diabetic pregnancies. In situ hybridization histochemistry was employed to investigate the distribution and abundance of IGF-I and IGF-II in peri-implantation and postimplantation conceptuses from normal and streptozotocin-treated diabetic mice. Animals were sacrificed on gestational days 5, 6, 7, 8, and 9. The entire uterine horn was prepared for hybridization with antisense and sense α-35S-dATP labeled oligonucleotide probes for IGF-I, IGF-II, and mouse β-actin. IGF-I transcript was apparent only in myometrium at 6 days of gestation in normal and diabetic mice. IGF-II transcripts were restricted to trophoectoderm cells within the implantation chamber on day 5. Following implantation, IGF-II transcripts were found in trophoectodermal derivatives, primitive endoderm, mesoderm, heart, walls of the foregut, and mesenchyme in normal and diabetic postimplantation conceptuses. There were no apparent differences between normal and diabetic samples in the distribution and abundance of the IGF-II transcript from gestational days 7, 8, and 9. The embryos from the diabetic mother at day 6 were growth retarded and had a significant decrease in the expression of IGF-II. These results suggest that maternal hyperglycemia may retard development of the early implanting conceptus in a narrow window around day 6 through a mechanism involving decreased IGF-II expression. Fetuses from diabetic pregnancies that escape this critical period appear to develop and express IGF-II in an equivalent manner to those of the control group. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370404
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    Insulin family growth factors have specific effects on protein synthesis in preimplantation mouse embryos (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 398-406 
    Details
    ISSN: 1040-452X
    Keywords: Preimplantation embryo ; Insulin ; IGFs ; Protein synthesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Previously constructed protein databases for two stages of preimplantation mouse embryogenesis, the compacted eight-cell stage and the fully expanded blastocyst stage, have been used to analyze the effects of insulin, IGF-I, and IGF-II on protein synthesis in these developmental stages. Proteins were labeled by placing, for 2 hr, synchronous cohorts of 35-50 embryos into human tubal fluid (HTF) medium containing L-[35S]-methionine (1 mCi/ml) in the presence or absence of one of the growth factors. The embryos were then washed with medium and lysed. Samples were processed for 2-D gel analysis. For each embryonic stage and each growth factor, four or five experimental replicates were done and the gel images were compared using the PDQUEST system. Using the computer-assisted analysis, we were able to identify proteins that showed a statistically significant (P 〈 0.05) change in synthesis. At the eight-cell stage of development insulin caused increased synthesis of two proteins and decreased synthesis in three proteins. Insulin-treated blastocyst stage embryos exhibited an increased synthesis in eight proteins and decreased synthesis for one protein. The effect of IGF-I at the eight-cell stage of development was mostly inhibitory; the synthesis of only one protein increased and the synthesis of five proteins showed a decrease. Similar results were obtained with blastocyst stage embryos; four proteins demonstrated an increase in synthesis while 14 proteins showed a decrease. Eight-cell stage embryos incubated with IGF-II had seven proteins with a decreased synthesis, although in blastocyst stage embryos, nine proteins showed increased synthesis. However, seven IGF response proteins were found to be proteins that showed significant changes in isotope incorporation during the eight-cell to blastocyst stage of development (Shi et al., 1993). In all, 54 proteins were affected, and these were unique; thus, protein synthesis in preimplantation mouse embryos is influenced by insulin and the IGFs, and further, each growth factor affects specific proteins. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370406
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    Characterization of the major proteins of bovine seminal fluid by two-dimensional polyacrylamide gel electrophoresis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 425-435 
    Details
    ISSN: 1040-452X
    Keywords: Seminal fluid proteins ; Isoelectric focusing ; Molecular heterogeneity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Recently, we demonstrated that the major proteins from bovine seminal plasma BSP-A1, -A2, -A3 and -30-kDa (collectively called BSP proteins) specifically interact with choline phospholipids. These proteins coat the surface of the spermatozoa after ejaculation and are believed to play an important role in membrane modifications occurring during capacitation. In this study we determined the isoelectric point (pl) and analysed the molecular heterogeneity of BSP proteins. Total protein from bovine seminal plasma (CBSP) and purified BSP proteins were iodinated using chloramine T. Samples were reduced, denatured, separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and visualized by autoradiography. Analysis of CBSP proteins demonstrated the presence of polypeptides migrating in the pH range of 3.5-7.8 and at molecular weights (Mr) between 6 and 100 kDa. Many isoforms of each BSP protein were found when purified iodinated proteins were analysed by 2D-PAGE. BSP-A1 was found at a Mr of 16.5 kDa and in the range of pl of 4.7-5.0; BSP-A2 at 16 kDa and at a pl of 4.9-5.2; BSP-A3 at 15 kDa and at a pl of 4.8-5.2, and BSP-30-kDa at 28 kDa and at a pl of 3.9-4.6. Similar results were obtained with immunolocalization of BSP proteins after Western blot using specific antibodies. The treatment of purified iodinated BSP proteins with neuraminidase increased the pl of BSP-30-kDa to 4.8-5.0 and decreased its Mr to 25 kDa, but no change was observed for BSP-A1, -A2 and -A3. The treatment of BSP proteins with sulfatase or acid phosphatase modified neither their Mr nor their pl. Furthermore, when CBSP proteins were separated in 2D-PAGE and the gels stained for glycoproteins with dansyl hydrazine, BSP proteins were among the major glycoproteins found in the bovine seminal plasma. In conclusion, BSP proteins are acidic and have several isoforms. Furthermore, the heterogeneity of BSP-30-kDa is mainly due to its sialic acid content. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370409
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    Characterization of mouse-hamster-human cross-reacting antioocyte monoclonal antibodies produced by intrasplenic immunization of mice with 12 zona-free mouse oocytes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 446-451 
    Details
    ISSN: 1040-452X
    Keywords: In vitro fertilization ; Fertilization-specific antibody ; Immunohistochemistry ; Mouse-hamster-human cross-reacting antibodies ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Several intrasplenic immunizations with batches of ∼15 or ∼30 zona-free, unfertilized mouse oocytes resulted in 200-300 hybrids, respectively, among which about 20 positive clones were selected from each fusion between splenic plasma cells and SP2/0 myeloma cells. When nonimmunized splenic plasma cells were used, only one antibody, showing weak immunoreaction, was obtained from ∼370 hybrids collected from 2 fusions. From one immunization with a total of 12 zona-free, unfertilized mouse oocytes, 15 positive clones were selected for further study. Eleven of these 15 antibodies reacted with antigens only in unfertilized oocytes but not in fertilized, pronuclear stage oocytes. Three antibodies, which recognized antigens in paraffin-embedded oocyte sections, did not label growing ovarian oocytes, indicating that the antibodies were specific to ovulated, unfertilized oocytes. These antibodies did not detect any antigen epitopes in the panel of tissues examined. The molecular weight of one antigen, corresponding to a IgM antibody that is present both in ooplasma and zona pellucida, was ∼116 kDa. Cross-reactivity to blots of unfertilized zona-free hamster oocytes was demonstrated by 6 antibodies and to unfertilized human oocytes by 7 antibodies. Three antibodies cross-reacted with both hamster and human oocytes. The study indicates that the intrasplenic immunization is an appropriate means of raising antibodies against unfertilized, zona-free mouse oocytes and that the method applied offers an easy way to select antibodies against human oocytes for functional studies. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370411
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    Spermophagy in semen in the red wolf, Canis rufus (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 457-461 
    Details
    ISSN: 1040-452X
    Keywords: Canine sperm ; Pyospermia ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The red wolf (Canis rufus) is an endangered species with 194 individuals remaining in the wild and in various captive facilities. Breeding efforts at the Graham, WA site (Point Defiance Zoo and Aquarium) have involved artificial insemination with fresh or frozen semen in an effort to increase population and maximize the genetic potential of the stock. Electron microscopic observations were made in semen specimens obtained by electroejaculation from mature males prior to their use in an effort to determine semen parameters that might be useful in guiding breeding procedures. Sperm samples were either fixed immediately or treated with capacitating media and fixed after 4 to 7 hr of incubation. Many of the specimens examined were pyospermic (white cell in semen) and showed evidence of spermophagy, primarily by neutrophils. Of the six animals surveyed, only one showed little evidence of spermophagy, and three had extensive pyospermia and spermophagy but this finding was not correlated with fertility. Samples fixed immediately as well as those incubated for several hours showed evidence of spermophagy, indicating that the phagocytosis was not the result of culture. Gene pool restriction and/or captive stress may be contributing factors of reduced semen quality. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370413
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    The human genome, by Tom Strachan, Bios Scientific Publishers, Oxford, U.K., 1992, 160 pp, $28 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 477-477 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370417
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    Electronic light microscopy: Techniques in modern biomedical microscopy, edited by David Shotten, Wiley-Liss, New York, 1992, 355 pp, $89.95 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 477-477 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370418
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    Effects of gonadotropins upon the incidence and kinetics of meiotic maturation of macaque oocytes in vitro (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 467-472 
    Details
    ISSN: 1040-452X
    Keywords: Oocyte maturation ; Germinal vesicle breakdown ; Polar body ; LH/FSH ; Macaque ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The specific aim of this study was to determine the effects of gonadotropins in vitro upon the incidence of and precise time interval to germinal vesicle breakdown (GVB) and extrusion of the first polar body (PB1) in oocytes from nonstimulated rhesus monkeys. Cumulus-enclod germinal vesicle (GV) stage oocytes from 10 normal, cycling rhesus monkeys in the follicular phase of the menstrual cycle were cultured with either: (1) 1.0 μg/ml human follicle-stimulating hormone (hFSH), (2) 10 μg/ml human luteinizing hormone (hLH), (3) 1.0 μg/ml hFSH and 10 μg/ml hLH, or (4) no gonadotropins (controls). Oocytes (n = 234) were examined at 3-hr intervals from 0 to 21 hr and at 4-hr intervals from 24 to 52 hr for GVB and PB1. Neither the incidence of GVB (hFSH: 63.5%; hLH: 56.1%; both gonadotropins: 63.1%; no gonadotropins: 53.6%) nor extrusion of PB1 (hFSH: 41.3%; hLH: 36.4%; both gonadotropins: 36.9%; no gonadotropins; 31.9%) differed (P 〉 0.05) among treatments. The time to GVB was accelerated (P 〈 0.05) by gonadotropins (hFSH: 10.8 ± 1.7 hr; hLH: 10.1 ± 1.8 hr; both gonadotropins: 8.8 ± 1.1 hr) when compared to controls (17.4 ± 2.0 hr). However, the time interval to extrusion of PB1 did not differ (P 〉 0.05) among treatments (hFSH: 32.3 ± 1.2 hr; hLH: 35.1 ± 1.4 hr; both gonadotropins: 35.2 ± 1.3 hr; no gonadotropins: 34.1 ± 1.2 hr). The mean interval to extrusion of PB1 was 34.1 ± 0.6 hr. In conclusion, GVB and PB1 extrusions appear to be, in part, independently regulated events in macaque oocytes matured in vitro since the timing of PB1 extrusion is not tightly coupled with the onset of GVB. Although the developmental potential of oocytes may be enhanced by gonadotropins, alternative approaches must be developed to improve the poor competence of oocytes from nonstimulated monkeys to mature in vitro. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080370415
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    Characterization of the main egg envelope proteins of the sea bass Dicentrarchus labrax L. (teleostea, serranidae) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 48-53 
    Details
    ISSN: 1040-452X
    Keywords: Fertilization ; Eggshell ; Electrophoresis ; Dicentrarchus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fish eggs are surrounded by a resistant acellular coat commonly called the chorion or zona radiata. This study characterizes the eggshell proteinaceous content of unfertilized eggs of the sea bass Dicentrarchus labrax, with a view to the prepration of immunogens. Solubilization of the purified eggshells was achieved in 8 M urea followed by one- and two-dimensional gel electrophoresis. Glycoproteins were detected using concanavalin-A in one and two-dimensional gels, and the principal glycoproteins had a molecular weight of 47 kDa and 170 kDa. Partial purification of a few polypeptides in the 45 kDa to 55 kDa range was achieved by gel filtration chromatography. Although whole eggshells were relatively insoluble even in 8 M urea, partial purification of these polypeptides enable them to dissolve completely in solutions at low ionic strength. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380109
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    Epididymal glycoprotein involved in rat sperm association (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 43-47 
    Details
    ISSN: 1040-452X
    Keywords: Spermatozoa ; Sperm maturation ; Sperm association ; Epididymis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Recently, a new head-to-head sperm association was described in the rat during epididymal transit. This association was called a rosette and a filamentous and PAS-positive material was also described joining the sperm heads. The begining of rosette formation in the epididymis and the linking material between heads have remained unclear. Epididymides of adult rats were fixed by vascular perfussion and thin sections of the principal regions were studied by transmission electron microscopy (TEM). The first evidence of rosette formation was observed in the distal corpus. Rosettes were isolated from the distal corpus and processed for immunogold and immunofluorescence microscopy to detect an epididymal glycoprotein called DE. This glycoprotein is secreted by the corpus epididymis and appears to be involved in sperm maturation. Colloidal gold marks and fluorescence were observed in the linking material between the sperm heads. The results presented here show that rosettes begin to appear following the sites of DE secretion and permit us to postulate that DE is involved in rosette formation and constitutes another example of gamete-epididymal interaction. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380108
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    Evidence for presence of hyaluronan binding protein on spermatozoa and its possible involvement in sperm function (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 69-76 
    Details
    ISSN: 1040-452X
    Keywords: Hyaluronic acid binding protein ; Sperm motility ; Phosphorylation ; Epididymal maturation ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hyaluronic acid, a major component of the extracellular matrix, plays an important role in the regulation of different cellular processes, e.g., locomotion, cell-cell interaction during morphogenesis, and differentiation. Distribution of hyaluronic acid with respect to the role of sperm hyaluronidase in sperm penetration and gamete interaction is well established. In order to elucidate this mechanism, in our current study we have identified and demonstrated, for the first time, the presence of a 68-kDa cell surface hyaluronic acid binding glycoprotein (HABP) in spermatozoa of different species (rat, mice, bull, and human) by immunoblot analysis and indirect immunofluorescence using the polyclonal antibodies raised against purified HABP. Furthermore, we were able to demonstrate a differential distribution of 68-kDa HA binding protein on the sperm head, midpiece, and tail of different species. To identify its role in sperm function, we observed its declining pattern during epididymal maturation and also the inhibition of sperm-oolemmal adherence by pretreatment of the sperms with anti-HABP antibodies. We have further observed its in vivo phosphorylation in motile spermatozoa. All our data clearly indicate that sperm hyaluronan binding protein may have a specific role in sperm maturation, motility, and fertilization processes. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380112
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    Activation of embryonic genes during preimplantation rat development (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 30-35 
    Details
    ISSN: 1040-452X
    Keywords: Rat embryo ; Transcription ; Protein synthesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Expression of the embryonic genome has been examined during preimplantation rat development. Proteins synthesized at different stages of embryogenesis were labelled with [35S]methionine and then separated by one-dimensional gel electrophoresis. A major transformation in the pattern of protein synthesis has been observed between the two- and the four-cell stages of embryonic development. Also the culture of embryos with an inhibitor of transcription (α-amanitin) has shown that the first α-amanitin-sensitive events take place during the late two-cell stage. However, inhibition of transcription does not arrest the embryo development up to the four-cell stage. Taken together, the results indicate that in rats the initiation of embryonic gene activation occurs at the late two-cell stage. However, the first two cleavage divisions can occur in the absence of transcription. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080380106
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    Evidence for a strong paternal effect on human preimplantation embryo development and blastocyst formation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 36-42 
    Details
    ISSN: 1040-452X
    Keywords: Human blastocyst formation ; Frozen sperm ; Abnormal sperm ; Human I.V.F. ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In human in vitro fertilization (I.V.F.), it was first assumed that all the embryos obtained had the same developmental potential whatever the quality of sperm. However, this has not been confirmed. We have used the coculture technique and determined the blastocyst formation rate in three groups of patients: group 1: patients with normal sperm count (〉20 × 106/ml), motility (〉30%), and morphology (〉50%); group 2: patients treated by I.V.F. with frozen donor sperm; group 3: patients with severely impaired sperm quality (〈3 × 106 forward motile and morphologically normal spermatozoa per ml). In group 1, we found a strong correlation between cleavage rate and blastocyst formation rate (P 〈 0.0001) with a blastocyst formation rate comprised between 40% and 50%. This was not true for the two other groups for which the overall number of blastocysts obtained and the number of patients having at least one blastocyst were severely reduced (P 〈 0.0001). These data are discussed in terms of DNA quality, timing of formation of the pronuclei, and delays in cell cycles at the time of genomic activation. These observations lead to a new approach to the study of fertilizing ability of poor quality sperm. It may help in the decision as to whether couples treated for male infertility should be excluded from I.V.F. protocols. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080380107
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    Calcium concentration and fertilization by subzonal insemination of a single spermatozoon in mouse oocytes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 54-60 
    Details
    ISSN: 1040-452X
    Keywords: Mouse spermatozoa ; Subzonal insemination ; Calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of calcium concentration in culture medium on the fertilization of subzonally microinseminated mouse oocytes was examined. Oocytes were injected with a single spermatozoon so that the sperm head was forced to adhere onto the ooplasmic membrane with a micromanipulation technique. For the inseminations, epididymal spermatozoa preincubated in culture medium and those treated with ionophore A23187 were used. Inseminated oocytes were cultured using media with three different calcium concentrations of 1.71, 3.42, and 5.13 mM; 40.0%, 71.6%, and 47.9% of oocytes microinjected with preincubated sperm were fertilized after incubation with those media, respectively. When the oocytes inseminated with ionophore-treated sperm were incubated in media containing 1.71 and 3.42 mM calcium, their fertilization rates were 58.2% and 87.5%. Thus fertility of subzonally microinseminated oocytes was obviously enhanced when cultured in medium with 3.42 mM of calcium, irrespective of being inseminated with preincubated sperm (P 〈 0.01) or with ionophore-treated sperm (P 〈 0.005). Some of the microinseminations with preincubated sperm were performed without sperm adhered to the oolemma. In these cases, the incidence of fertilization was not improved by incubating the inseminated oocytes in medium containing 3.42 mM calcium (32.6%) as compared to those incubated in medium with 1.71 mM calcium (28.3%). These results suggest that the concentration of extracellular calcium exerts an important effect on the progress of fertilization events subsequent to sperm adherence onto the ooplasmic membrane. Almost 80% of the zygotes fertilized via incubation in medium with 3.42 mM of calcium developed into blastocysts after culturing in vitro. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080380110
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    Bovine nuclear transfer embryos: Oocyte activation prior to blastomere fusion (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 61-68 
    Details
    ISSN: 1040-452X
    Keywords: Nuclear transfer ; Bovine ; Activation ; Oocyte ; Embryo ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Successful bovine nuclear transfer (NT) embyro production requires proper oocyte activation and transfer of a nucleus into this oocyte. However, the temporal relationship between these two events is unclear. The current study examined whether activation of the oocyte prior to fusion would induce nuclear swelling while also affecting development to morula and blastocyst stage and finally development to offspring. Aged oocytes can be activated by a number of techniques including exposure to room temperature. In this study oocyte activation was induced through three different means: reduced temperature culture alone, reduced temperature culture and calcium ionophore, and naturally, through the fertilization process. Electrofusion was carried out after the activation stimulus. When used in the NT procedure, activation of oocytes prior to fusion resulted in NT embryos that under went nuclear swelling and had a high developmental rate to morula and blastocyst stages. Also, these NT embryos developed to normal offspring when transferred to recipient animals. The addition of a calcium ionophore treatment to the reduced temperature culture was not beneficial and resulted in less nuclear swelling. The use of enucleated fertilized oocytes as recipient cytoplasm for the new nucleus resulted in NT embryos developing to morula and blastocyst stages at the same rate as room temperature activated NT embryos. Therefore, improved embryo development can be obtained from NT embryos if the aged recipient oocyte is activated prior to the time of fusion. Also, offspring were obtained from these pre-activated NT embryos. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380111
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  • 147
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    Rapid, nonradioactive, and quantitative method to analyze zona pellucida modifications in single mouse eggs (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 91-93 
    Details
    ISSN: 1040-452X
    Keywords: Zona pellucida ; Egg activation ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A rapid, nonradioactive method to monitor the ZP2 to ZP2f conversion in the zona pellucida of single mouse eggs has been developed. This assay is based on the chemiluminescent detection of biotinylated ZP2 and ZP2f following electrophoresis under reducing conditions and electrophoretic transfer to Immobilon P. This method is about 10 times faster and detects similar extents of ZP2 to ZP2f conversion following A23187-induced egg activation, when compared to the commonly used radioiodination procedures. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380115
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  • 148
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    Computerized analysis of the motility parameters of hamster spermatozoa during maturation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 94-106 
    Details
    ISSN: 1040-452X
    Keywords: Epididymal spermatozoa ; Motility patterns ; VCL ; VSL ; VAP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A computer-aided semen analysis system was used for the objective assessment of hamster spermatozoa during epididymal maturation. The caput epididymal spermatozoa were extremely sluggish, achieved very little progression, and the three velocity parameters, namely curvilinear velocity (VCL), progressive velocity (VSL), and path velocity (VAP), were low. These spermatozoa during progressive movement alternated between the linear shape and “U” shape or attained an “S” shape prior to changing to the “U”; shape. The corpus epididymal spermatozoa were faster, displayed greater VSL, VAP, and VCL compared to caput epididymal spermatozoa, and, during forward motility, attained “U,” “C,”; and (or) “?” shape as in the wriggling motility pattern. The proximal cauda epididymal spermatozoa were actively motile and VSL, VAP, and VCL in these spermatozoa were more than 10 times greater compared to the caput epididymal spermatozoa. The proximal cauda epididymal spermatozoa predominantly moved in circles and with time became slower and more circular in their trajectories and exhibited a reduction in LIN (linearity). The distal cauda epididymal spermatozoa were very similar to the proximal cauda epididymal spermatozoa with respect to their fast motility (VSL, VAP, and VCL are similar) and beat cross frequency (BCF), but showed larger values for STR (straightness) and LIN and moved along curved trajectories. The amplitude of lateral head displacement (ALH) was also considerably lower in the distal cauda epididymal spermatozoa compared to the proximal cauda epididymal spermatozoa. Thus, this study provides for the first time data related to seven motility parameters for caput and corpus epididymal spermatozoa of hamster. It also provides additional data with respect to VCL, LIN, BCF, and ALH for proximal and distal cauda epididymal spermatozoa of hamster. © 1994 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380116
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  • 149
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    Redistribution of nuclear antigens linked to cell proliferation and RNA processing in mouse oocytes and early embryos (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 119-130 
    Details
    ISSN: 1040-452X
    Keywords: Mouse embryos ; Nuclear antigens ; Cell proliferation ; sn-RNP ; Transcriptional activity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have systematically analyzed by indirect immunofluorescence the subcellular distribution of nuclear antigens in relation to developmental stages of maturing mouse oocytes and developing embryos. Antigens were of two types: (1) a protein whose nuclear localization in interphase somatic cells depends on their proliferative state protein recognized by a monoclonal antibody 43B1N, and (2) snRNP polypeptides recognized by autoimmune sera of anti-Sm and anti-RNP type. The protein recognized by 43B1N was present in the germinal vesicle of oocytes from antral follicles, but absent from the nuclei during the first hours of embryonic life up to the middle to late 2-cell stage. Starting from this stage, it was always found in nuclei of interphase blastomeres, where its “speckles”; co-localized with the speckles containing high concentrations of snRNP polypeptides. SnRNP polypeptides recognized by anti-Sm and anti-RNP sera were in turn found in nuclei of all developmental stages. When embryos were treated with aphidicolin or cytochalasin D to arrest cell division, the 43B1N reacting protein was again localized in the pronuclei at 42 hr post-hCG, i.e., slightly later than the onset of transcriptional activity. These results suggest a progressive building up of nuclei during embryonic development, which could influence gene expression. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380202
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  • 150
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380201
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  • 151
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    Storage of messenger RNA in eukaryotes: Envelopment with protein, translational barrier at 5′ side, or conformational masking by 3′ side? (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 107-117 
    Details
    ISSN: 1040-452X
    Keywords: Masked mRNA ; mRNPs ; mRNA-binding proteins ; Translational repression ; mRNA stability ; mRNA storage in germ cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Messenger RNA can be stored in the cytoplasm of higher Eukaryotes in the form of masked messenger ribonucleoprotein particles (masked mRNPs, or informosomes). The typical example is the storage of mRNPs in germ cells (oocytes and spermatocytes). The masked mRNPs are inactive in translation, stable, i.e., protected against degradation, and unavailable for poly(A) tail processing, such as cytoplasmic polyadenylation and deadenylation. The major nonspecific mRNA-binding protein forming mRNPs and belonging to a special p50 family of basic, glycine-rich, phosphorylatable proteins seems to be necessary, but not sufficient for the masking. In some cases, mRNA-specific repressor proteins bound to the 5′-untranslated regions (5′-UTR) of mRNAs may be involved. Interactions of the 3′-untranslated regions (3′-UTR) with sequence-specific proteins seem to be of decisive importance for the masking of mRNPs. The hypothesis is proposed that the masking is achieved through a 3′-UTR-induced conformational rearrangement of mRNP; closing into a circle and condensation of mRNP are considered plausible. © 1994 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380117
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  • 152
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    Assessment of sister chromatid exchange in mouse embryos produced by microsurgical fertilization (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 142-147 
    Details
    ISSN: 1040-452X
    Keywords: Micromanipulation ; Zona pellucida ; DNA repair ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The treatment of male factor-related infertility has been approached with the advent of several methods for microsurgical fertilization, such as the partial dissection of the zona pellucida (PZD) and the injection of sperm into the perivitelline space (PVSI) of oocytes. These techniques are designed to increase sperm-oolemma interaction by circumventing passage of the sperm through the zona pellucida. The present study was performed to evaluate the influence of PZD and PVSI on the in vitro development of mouse embryos by assessing the rate of sister chromatid exchange (SCE). SCE is considered to be a sensitive indirect indicator of DNA lesions due to various conditions. Oocytes were cultured in vitro after PZD or PVSI and then examined for SCE. There was no significant difference in SCE between control and treatment groups of embryos and the values were similar to those reported by Saito et al. (Fertil Steril 41:460-464, 1984). The rate of SCE was low during the first two mitotic cycles, then increased from cycle two to three before declining slightly between the 3rd and 4th cycles of cell division. These data demonstrate that the direct interaction of sperm and oocyte by PZD or PVSI did not have an adverse effect on the development of mouse embryos as assessed by the rate of SCE. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380204
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  • 153
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    In vitro incubation of golden (syrian) hamster ovarian oocytes and human sperm with a human oviduct specific glycoprotein (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 160-169 
    Details
    ISSN: 1040-452X
    Keywords: Oviductal glycoprotein ; Gametes ; Immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The objective of this study was to determine if human oviduct specific glycoprotein (huOGP) would associate with hamster ovarian oocytes and human sperm during in vitro incubation. The huOGP used in these studies was partially purified from human hydrosalpinx fluid. Hamster ovarian oocytes and human sperm samples were incubated in culture medium with and without huOGP. Association of huOGP was assessed by indirect immunofluorescence assay using a polyclonal antibody prepared against huOGP. Intense fluorescence of the zona pellucida, and bright but uneven fluorescence of the perivitelline space, were observed in hamster ovarian oocytes following incubation in the presence of huOGP. A similar but more uniform pattern of fluorescence was observed when hamster oviductal oocytes (positive controls) were incubated in culture medium alone. Fluorescence was absent when oocytes were assayed with preimmune serum. The association of huOGP with the zona pellucida and perivitelline space appeared to be specific since thyroglobulin, a large molecular weight glycoprotein, and human serum albumin, the major protein in oviduct fluid, did not associate with the hamster oocytes nor inhibit huOGP association when included in the culture medium. Fluorescence was absent when human sperm incubated with huOGP were assayed with antiserum to huOGP. However, human sperm fluoresced when incubated with a uterine glycoprotein, CUPED, which had previously been shown to bind to cat sperm during in vitro incubation. Sperm also fluoresced brightly when human sperm antibody was used as a positive control. Solubilization of sperm membrane proteins postincubation and analysis of these proteins by 1-D SDS-PAGE followed by immunoblotting also failed to show an association of huOGP with human sperm. Electron microscopy of sperm both pre- and postsolubilization confirmed that the sperm membranes were removed by this process. In conclusion, the association of huOGP with hamster oocytes in vitro suggests that huOGP may associate with human oocytes in vivo, whereas that may not be true for human sperm in vivo. The association of huOGP with oocytes may serve to facilitate the process of fertilization and early embryonic development within the oviduct. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380207
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  • 154
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    Temporal and spatial expression of leukemia inhibitory factor in rabbit uterus during early pregnancy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 148-152 
    Details
    ISSN: 1040-452X
    Keywords: Leukemia inhibitory factor ; Rabbit ; Endometrium ; Blastocyst implantation ; Pregnancy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Leukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to document the appearance of LIF in the rabbit uterus during early pregnancy and to determine whether changes just prior to implantation, similar to those in mice, occurred. LIF was localized in endometrial epithelium, myometrium, and endometrial glands. A low level of LIF was detected in the uterus of nonestrous and estrous females. LIF expression reached its highest level on day 5 of pregnancy and declined on days 6 and 7. By day 13 of pregnancy, little endometrial LIF was apparent. The expression of LIF on day 5 of pseudopregnancy was similar to that on day 5 of pregnancy. LIF expression was much higher at implantation sites than that at nonimplantation areas on day 7 of pregnancy. It is concluded that LIF may be important for the implantation of rabbit blastocysts. © 1994 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380205
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  • 155
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    Mouse preimplantation embryo development in vitro: Effectof sodium concentration in culture media on RNA synthesis and accumulation and gene expression (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 131-141 
    Details
    ISSN: 1040-452X
    Keywords: Mouse preimplantation development ; Reverse transcription-PCR ; Culture median ; RNA synthesis ; mRNA ; Gene expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Results of previous studies indicate that culture of preipmlantation mouse embryos in SOM medium containing 85 mM NaCl promotes better development in vitro, as well as supporting higher rates of protein synthesis, when compared to culture in SOM containing 125 mM NaCl (Anbari and Schultz, 1993, Mol Reprod Dev 35:24-28; Biggers et al., 1993, Mol Reprod Dev 34:380-390). In the present study we compare the effect of culturing embryos in these 2 media on several aspects of RNA synthesis and gene expression in order to determine whether the reduced development in SOM containing 125 mM NaCI and lower rates of protein synthesis are correlated with decreases in RNA synthesis and stability and changes in gene expression. Although no apparent differences in the metabolism of [3H]uridine to UMP, UDP, and UTP and its incorporation into total RNA are observed when 2-cell embryos are cultured to the morula stage in either medium, a 20% decrease in the rate of mRNA synthesis is found when embryos are cultured in SOM containing 125 mM NaCl. In addition, pulse-chase experiments reveal that total mRNA is less stable when the embryos are cultured in SOM containing 125 mM NaCl. Using a reverse transcription-polymerase chain reaction to assay for changes in the relative amounts of specific mRNAs, the relative amounts of mRNAs for IGF-I and IGF-II and their cognate receptors are dramatically reduced in embryos cultured in SOM containing 125 mM NaCl, whereas only a mild reduction is observed in the relative amount of actin mRNA. In contrast, when freshly isolated morulae are cultured to the blastocyst stage in either of these 2 media, similar amounts of these mRNAs are observed. Last, high-resolution, 2-dimensional gel electrophoresis reveals significant changes in the pattern of protein synthesis when the embryos are cultured in SOM containing 125 mM NaCl. Results of these experiments suggest that culture of embryos in medium containing lower concentrations of NaCl that are normally present in various culture media results in higher rates of mRNA synthesis and greater mRNA stability. These changes in RNA synthesis may underlie, at least in part, the improved development in vitro that is fostered by SOM containing 85 mM NaCl. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380203
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  • 156
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    Calmodulin during human sperm incorporation into hamster oocyte: An immunogold electron microscope study (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 170-177 
    Details
    ISSN: 1040-452X
    Keywords: Calmodulin ; Actin ; Human sperm ; Golden Syrian hamster oocyte ; Fertilization ; Immunogold electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the present study, immunogold labeling of ultrathin sections of human sperm, before and after incorporation into hamster oocyte, was used to obtain insight into the ultrastructural localization and possible function of calmodulin during fertilization. In heads of ejaculated, capacitated, and acrosome-reacted fixed human sperm, calmodulin was mainly found in two compartments, the subacrosomal layer and the postacrosome. After sperm-egg fusion, the subacrosomal calmodulin was unaltered and surrounded by the fertilization cone in which actin was abundant. There was no co-localization of calmodulin and actin. In contrast, postacrosomal calmodulin disappeared as soon as the sperm head was incorporated into egg cytoplasm. These unique localizations and redistributions are in agreement with the concept of a calmodulin targeting from acrosome toward postacrosome through the subacrosomal layer during spermatogenesis (Weinman et al., 1986b: J Histochem Cytochem 34:118). Moreover, they strongly suggest a role for calmodulin both in sperm-egg fusion and in the initial pulse of Ca2+ occurring during fertilization. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380208
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  • 157
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    Effects of transforming growth factors and activin-A on in vitro porcine oocyte maturation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 153-159 
    Details
    ISSN: 1040-452X
    Keywords: TGF-α ; TGF-β ; Oocytes ; Cumulus cells ; Gap junctions ; Maturation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Growth factors are known to regulate ovarian function. In the present study, effects of these growth factors, TGF-α, TGF-β, and activin-A were tested on spontaneous porcine oocyte maturation. Cumulus-oocyte complexes (COC) were cultured in the presence of TGF-α, TGF-β, and activin-A for 48 hr. Stages of meiotic maturation were assessed by staining with acetic orcein. Among these factors, only TGF-α significantly enhanced the maturation rate, whereas TGF-β suppressed the spontaneous maturation rate. The site of action of TGF-α on COC and the interaction between TGF-α and EGF receptor was also examined. Denuded oocytes, alone or in coculture with cumulus cells, were cultured in the presence of TGF-α for 48 hr. TGF-α did not have any significant effect on denuded oocyte maturation. Heptanol was employed to investigate the role of gap junctions on TGF-α-induced oocyte maturation in COC. Although heptanol did not have any significant effect in the control medium, heptanol reversed the stimulatory effect of TGF-α on porcine oocyte maturation. TGF-α was able to displace 125I-EGF binding on COC. In conclusion, TGF-α enhances the spontaneous maturation of porcine oocytes by generating positive signal(s) in cumulus cells that are transferred to the oocyte via gap junctions. TGF-α shares the same receptor with EGF on porcine COC. TGF-β, in contrast, inhibits porcine oocyte maturation. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380206
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  • 158
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    Plasma membrane block to sperm entry occurs in mouse eggs upon parthenogenetic activation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 200-208 
    Details
    ISSN: 1040-452X
    Keywords: Polyspermy block ; Oolemma ; Fertilization ; IP3, CGE ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ability of parthenogenetically activated mouse eggs to establish a plasma membrane (PM) block to sperm penetration was studied. Zona-free eggs preloaded with Hoechst 33342 were activated by exposure to ethanol or OAG (1-oleoyl-2-acetyl-sn-glycerol) and inseminated after different periods. Eggs challenged with sperm at 30- or 60-min postactivation displayed a fertilization frequency significantly lower than that of control eggs. Conversely, when insemination was carried out at 120-min postactivation, the proportion of fertilized eggs was equivalent to that observed in the control group. Moreover, we report that when the eggs were induced to resume meiosis without any notable loss of CGs (egg exposure to OAG at 100 μM external Ca2+ or to heat shock), a normal ability to be penetrated was recorded at 30-min postactivation. Similar behaviour was exhibited by eggs that underwent a CG exocytosis close to that triggered by sperm in absence of nuclear activation (microinjection of inositol 1,4,5-trisphosphate into the egg at 1 μM cytosolic concentration). Present data support the conclusion that parthenogenetically activated mouse eggs are capable of a transitory PM block response that requires both CG exocytosis and meiosis resumption to occur. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380211
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  • 159
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    Fertilization current in the human oocyte (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 209-214 
    Details
    ISSN: 1040-452X
    Keywords: Human oocyte activation ; Ion currents ; Intracellular regulating mechanisms ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In this report we show that the first event of activation in the human oocyte, the Fertilization current (FC), is a slow transient outward current of 300 pA, which induces a gradual hyperpolarization of the plasma membrane from -20mV to -60mV, 60-120 min after insemination, followed by a repolarization to -20mV. Activation currents (AC) of 600-2,500 pA, induced by exposure to the calcium ionophore A23187 or by microinjection of InsP3 into the cytosol, are also outward. The AC are inhibited by preloading oocytes with EGTA suggesting they are calcium dependent. Since AC are 2-10-fold the amplitude of the FC the fertilizing spermatozoon in the human only activates a portion of the primary elements stored in the oocyte for triggering metabolic depression. Oocyte activation in the human resembles that in the hamster rather than other mammals or invertebrates studied to date. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380212
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  • 160
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    Actin in the acrosome of the spermatozoa of the crab, Cancer pagurus L. (decapoda, crustacea) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 178-186 
    Details
    ISSN: 1040-452X
    Keywords: Immunofluorescence ; Cytoskeltal proteins ; Antibody ; Gel electrophoresis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The cytoskeletal protein actin was identified in the mature spermatozoon of the European edible crab, Cancer pagurus Linnaeus, by indirect immunofluoresce with monoclonal and polyclonal anti-actin antibodies, fluorescent phalloidin, and DNAase I. The actin was localized in two distinct concentric rings within the acrosome vesicle of the spermatozoon and appeared to correlate with the internal zonation of the vehicle. Modifications of the fluorescent pattern for actin were observed in sperm cells which were undergoing changes associated with the acrosome reaction. In these cases, fluorescent staining was observed in the nucleocytoplasm immediately subjacent to the perforatorial column and sometimes in the perforatorial column within the acrosome vesicle. Equally intense fluorescence was observed in an apical perforatorial projection. SDS-PAGE of C. pagurus sperm confirmed the presence of actin in the cells. A single band of actin (approximately 43 kDa) comigrated with rabbit muscle actin when immunoblotted onto nitrocellulose with mouse monoclonal anti-actin. The actin-associated cytoskeletal proteins α-actinin, tropomyosin, and spectrin were also identified within the spermatozoon of C. pagurus using specific polyclonal antibodies, but their presence was not confirmed by SDS-PAGE and immunoblotting. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380209
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    Stimulating effect of pyroglutamylglutamylprolineamide, a prostatic, TRH-related tripeptide, on mouse sperm capacitation and fertilizing ability in vitro (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 215-221 
    Details
    ISSN: 1040-452X
    Keywords: Chlortetracycline ; In vitro fertilization ; Fertilization promoting peptide ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pyroglutamylglutamylprolineamide, a prostatic tripeptide with structural similarities to thyrotrophin-releasing hormone (TRH), has been found in the seminal plasma of several mammalian species, suggestive of a biological function relating to spermatozoa. Using chlortetracycline (CTC) fluorescence analysis and in vitro fertilization, we have obtained evidence that the tripeptide stimulates mouse sperm capacitation and fertilizing ability in vitro. The tripeptide at concentrations from 5-500 nM was added to sperm suspensions and cells were assessed with CTC after 40 min, insufficient time for complete capacitation by a majority of spermatozoa under standard conditions of incubation. Concentrations of 25 nM and higher significantly promoted capacitation, as evidenced by a decrease in the proportion of acrosome-intact F pattern spermatozoa, characteristic of uncapacitated cells, and an increase in the proportion of acrosome-intact B pattern spermatozoa, characteristic of capacitated cells. However, there was no significant stimulation of acrosomal exocytosis. These results suggested that peptide-treated cells would be more fertile than their untreated counterparts. This was confirmed using in vitro fertilization, where the presence of 100 nM peptide during sperm preincubation and gamete coincubation significantly stimulated fertilizing ability (peptide, 56.5% of oocytes fertilized; controls, 26.5%). Comparison of the prostatic tripeptide and TRH effects on capacitation revealed that TRH at a concentration of 250 nM was as effective as the prostatic tripeptide in promoting the F & B transition but was less effective or ineffective at lower concentrations. In vitro fertilization assessment of the two peptides, at 100 nM, revealed that only the prostatic tripeptide significantly stimulated fertility. Again, this was consistent with the CTC analyses. Because the prostatic tripeptide can stimulate sperm function in vitro, it is possible that it plays a similar role in vivo and promotes fertilizing ability of ejaculated spermatozoa. We therefore propose that this tripeptide be referred to as fertilization promoting peptide (FPP). © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380213
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    Mouse oocyte maturation is affected by lithium via the polyphosphoinositide metabolism and the microtubule network (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 187-199 
    Details
    ISSN: 1040-452X
    Keywords: Mouse oocyte ; Meiosis ; Lithium ; InsP3 ; myo-inositol ; Chromatin ; Microtubules ; Cell cycle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The incubation of mechanically denuded mouse oocytes in medium containing LiCl delayed both germinal vesicle breakdown (GVBD) and polar body extrusion in a dose-dependent and reversible manner. When myo-inositol alone was added to the culture medium, we observed that it accelerated GVBD and increased the rate of polar body extrusion, whereas, when combined with LiCl, the normal timing of GVBD was recovered. In the same way, when inositol trisphosphate (InsP3) was microinjected into the ooplasma, we observed an important improvement of the rate of GVBD, as compared to control oocytes, and prevention of lithium inhibition. However, neither myo-inositol nor InsP3 were able to rescue totally the oocytes from the negative effect of lithium on polar body extrusion. Moreover, lithium induced some important changes in microtubule and chromosome organizations. Before extrusion of the first polar body, the reduction of the spindle size or the appearance of short individualized chromosomes dispersed around a large aster of microtubules were often observed, whereas, after polar body extrusion, the spindle appeared smaller and chromosomes were often trapped in the midbody. Thus lithium affects mouse oocyte maturation at two different levels: GVBD and polar body extrusion. Whereas the former seems to be affected via polyphosphoinositide turnover, the latter is InsP3-independent and seems to be influenced negatively via underdevelopment of microtubular structures. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380210
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  • 163
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    Announcement (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 238-238 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380216
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  • 164
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    Analysis of mRNA for class I HLA on human gametogenic cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 231-237 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have studied mRNA expression for Class I HLA (human leukocyte antigen) on male germ cells by amplification of gene fragments in PCR techique and by Northern hybridization. RNA was extracted from fractionated gametogenic cells (isolated from testis) and reversely transcribed. Then, cDNA was amplified for specific HLA sequence (1151 bp) representing whole-length coding sequence (HLA, -A, -B, -C). The specificity of this product was confirmed in “nested” PCR of 400 bp gene fragment coding for alpha 2 domain, alpha 3 domain, and the transmembrane portion of Class I HLA. The results indicate minimal expression of classical Class I HLA on gametogenic cells. Northern hybridization with 669 bp cDNA fragment (spanning for alpha 3 domain, transmembrane, cytoplasmic, and 3′ untraslated region) resulted in a low intensity signal from gametogenic cell fractions and confirmed our findings obtained by PCR. The minimal expression of classical HLA antigens may create a neutral cover for the male reproductive system, thereby preventing an immunological response during germ cell differentiation. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380215
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  • 165
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380301
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  • 166
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    Affinity binding of hamster oviductin to spermatozoa and its influence on in vitro fertilization (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 322-327 
    Details
    ISSN: 1040-452X
    Keywords: Oviduct ; Glycoprotein ; Gamete recognition ; Acrosome ; Cumulus oophorus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The aim of this study was to determine the influence of hamster oviductal glycoprotein (Oviductin) on in vitro gamete interaction. Oviductin was purified from the oviducts using lithium 3,5-diiodosalicylate, followed by phenol extraction. Immunocytochemistry using indirect fluorescence staining revealed that oviductin binds to the sperm anterior acrosomal region. The specific binding of oviductin resulted in inhibition of in vitro fertilization in studies using cumulus-free oocytes. The inhibitory effect was dependent on the concentration of oviductin and occurred in both ovarian and oviductal oocytes but not zona-free oocytes, indicating that sperm-zona interaction was interferred by oviduction. However, the inhibitory effect of oviductin sperm-zona interaction was reduced when cumulus-enclosed oocytes from ovaries and oviducts were used, indicating that the egg investment including cumulus oophorus has some effect on oviductin-sperm complex and maintaining the fertilizing ability. © Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390309
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  • 167
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    Calcium influx into mouse spermatozoa activated by solubilized mouse zona pellucida, monitored with the calcium fluorescent indicator, fluo-3. inhibition of the influx by three inhibitors of the zona pellucida induced acrosome reaction: Tyrphostin A48, pertussis toxin, and 3-quinuclidinyl benzilate (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 297-308 
    Details
    ISSN: 1040-452X
    Keywords: Sperm signal transduction ; Br-A23187 ; Acrosomal exocytosis ; Sperm G1 protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The fluorescent calcium indicator, fluo-3, was loaded as the membrane permeant tetraacetoxymethyl (AM) ester into cauda epididymal mouse sperm at 25°C for 20 min in the absence of bovine serum albumin (BSA) and presence of the dispersant, Pluronic F-127. Excess indicator was removed by two centrifugation washes at 100g for 10 min, a procedure that did not impair sperm motility. Upon resuspension in medium containing 20 mg/ml BSA to promote capacitation, the sperm cells exhibited readily detectable fluorescence uniformly distributed in the cytoplasm. Cell fluorescence was stable over the time of the experiments and was responsive to changes in intracellular calcium concentration, [Ca2+]j. Initial [Ca2+]j was 231 ± 58 nM (±SE, n = 43). Addition of heat-solubilized mouse zonae pellucidae to capacitated sperm increased [Ca2+]j by 106 ± 19 nM (±SE, n = 18), the higher steady-state concentration being reached after 30 min. Subsequent addition of the non-fluorescent calcium ionophore Br-A23187 resulted in a further increase of 114 ± 18 nM (± SE, n = 18), the higher steady-state concentration being reached after 6 min. The increase in [Ca2+]j induced by solubilized zonae pellucidae was largely blocked by 3-quinuclidinyl benzilate (QNB) an antagonist of muscarinic receptors that was earlier shown to block the zona pellucida induced acrosome reaction in mouse sperm (Florman and Storey, 1982: Dev Biol 91:121-130). This [Ca2+]j increase was completely blocked by the tyrosine kinase inhibitor, tyrphostin A48, and by the inactivator of G1 proteins, pertussis toxin. At the concentrations at which they blocked the zona pellucida-induced increase in [Ca2+]j all three inhibitors also blocked the zona pellucidainduced acrosome reaction. These results indicate that [Ca2+]j increase in is an early, if not the initial, reaction in the sequence leading to zona pellucida induced acrosomal exocytosis in mouse sperm. The observation that the three inhibitors, each having a different mode of action, all block the zona pellucida induced [Ca2+]j suggests that the sperm plasma membrane receptors mediating the zona pellucida induced acrosome reaction may function as a complex, whose formation is activated by zona pellucida ligand binding. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390307
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  • 168
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    Development of IVM-IVF produced 8-cell bovine embryos in simple, serum-free media after conditioning or Co-culture with buffalo rat liver cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 251-255 
    Details
    ISSN: 1040-452X
    Keywords: Bovine ; In vitro fertilization ; Buffalo Rat ; Liver cells ; Co-cultures ; Embryo culture ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Development of 8-cell bovine embryos derived from in vitro matured/in vitro fertilized (IVM/IVF) oocytes was evaluated in two simple, serum-free media (CZB and SOM) with buffalo rat liver cells co-culture (BRLC) or after conditioning compared to a commonly used, serum-supplemented complex medium TCM-199. In a 3 x 4 factorial design, 578 eight-cell embryos were randomly assigned to 12 treatment groups. The factors were: first, type of culture medium (M199/FBS, CZBg and SOM), and second, the use of BRLC (as co-culture or to condition media for 24 hr and 48 hr) and unconditioned media. Development to morula was not affected by the type of medium, but co-culture and 48 hr conditioning within media type resulted in better development when compared to the 24-hr conditioned or unconditioned groups. Blastocyst development in SOM (38.9%) was different (P 〈 0.05) than in CZBg (46.6%) and M199/FBS (48.7%) and was lowest in the unconditioned group (27.8%) followed by 24 hr conditioned (33.3%), 48 hr (56.3%), and co-culture (59.6%). No blastocyst expansion was observed with unconditioned media and 24 hr conditioned SOM. Significant differences (P 〈 0.05) were found among all treatment groups except the co-culture and 48-hr conditioned groups. Hatching occurred only with co-culture and 48-hr conditioned groups of M199/FBS and CZBg media. These data show that CZB with glucose conditioned by BRLC monolayers for 48 hr can support the development of IVM/IVF produced bovine embryos to blastocyst compared to culture in TCM-199 with serum. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/mrd.1080380304
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  • 169
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    Liposome-mediated DNA transfer into chicken primordial germ cells in vivo (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 268-274 
    Details
    ISSN: 1040-452X
    Keywords: Transfection ; lacZ ; Intravascular injection ; RSV ; β-actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In embryogenesis, avian primordial germ cells (PGCs) circulate temporarily in the blood vessels at stages 10-15 (Hamburger and Hamilton, 1951), before reaching the gonads. In an attempt to transfer cloned genes into PGCs, liposome consisting of reporter plasmid DNA and N-[1-(2,3-Dioleoyloxy)propyl]-N, N, N-trimethyl-ammoniummethylsulfate was injected into the marginal veins of embryos at stages 11--15. As reporter plasmids, pRSVZ and pAcZ harboring the Escherichia coli lacZ gene driven, respectively, by the Rous sarcoma virus (RSV) promoter and the chicken β-actin gene promoter were used. First, 55 embryos were injected with liposome containing pRSVZ and stained for the bacterial β-galactosidase activity 24 hr after injection. In all the embryos, cells positive for β-galactosidase activity were observed among the blood cells, endothelial cells, and endocardium cells of the heart, suggesting that transfection took place within the circulatory system. Then, embryos were injected with liposome containing pRSVZ or pAcZ, and stained 2 or 3 d after injection. PGCs positive for β-galactosidase activity were observed in the gonads in four out of 44 embryos injected with pRSVZ, and 29 out of 71 embryos injected with pAcZ, indicating that the plasmid DNA was transferred into PGCs developing normally. The average number of positive PGCs per embryo was 0.2 and 2.1, respectively, when pRSVZ and pAcZ were introduced. The difference in the number of positive PGCs detected after introduction of the two plasmids suggests that the actin promoter has a higher level of transcriptional activity in PGCs than does the RSV promoter. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380307
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  • 170
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    Cleavage and 3H-uridine incorporation in bovine embryos of high in vitro developmental potential (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 375-383 
    Details
    ISSN: 1040-452X
    Keywords: In vitro fertilization ; Bovine ; Embryo ; Genome Activation ; Transcription ; 3H-Uridine ; α-Amanitin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The timing of genome activation in bovine embryos is still not well defined. The objective of this study was therefore to investigate transcription in bovine embryos with a high potential to develop in culture after in vitro fertilization, by examining, autoradiographically, their incorporation of 3H-uridine. Initial experiments determined that developmental potential in vitro could be related to the time of first division of the zygote. Embryos that completed their first cleavage within 30 hours of exposure to sperm were more likely to develop into blastocysts (65.7%) and to hatch (50.9%). Using such embryos, it was found that 10 of 12 8-cell and all 11 4-cell stage embryos were labeled after a 2-4-hr exposure to 3H-Uridine. Among 2-cell stage embryos, 0 of 23, 3 of 17, 8 of 15, and 3 of 4 were labeled after exposure to 3H-uridine of 2, 4, 7, and 10 hr, respectively. Treatment with α-amanatin (10-100 m̈g/ml) blocked 3H-uridine incorporation but did not inhibit cleavage during the first 4 cell cycles. It was concluded that transcription occurs as early as the 2-cell stage in bovine embryos in vitro but is not critical to the first four cell cycles. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390405
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  • 171
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    Implication that potassium flux and increase in intracellular calcium are necessary for the initiation of sperm motility in salmonid fishes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 409-414 
    Details
    ISSN: 1040-452X
    Keywords: K+ channel blockers ; K+ electrode ; Fura-2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Flux of K+ and changes in intracellular Ca2+ in the sperm of salmonid fishes were measured with spectrophotometry, ion electrode, microscopic fluorometry, and radioisotope accumulation. Release of K+ occurred at the initiation of sperm motility which is induced by decrease in external K+ and the K+ efflux and sperm motility were inhibited by K+ channel blockers. Intracellular Ca2+ increased within a short period in K+- free condition, and the accumulation of 45Ca in sperm cells was higher in motile sperm than that in immotile sperm. The efflux of K+ and the increase in intracellular Ca2+ were suppressed when external K+ concentration increased, i.e., sperm remained immotile. These results suggest that efflux of K+ through K+ channel and subseqent increase in intracellular Ca2+ are prerequisite for the initiation of sperm motility. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390409
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  • 172
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    Solubilization and partial purification from mouse sperm membranes of the specific binding activity for 3-quinuclidinyl benzilate, a potent inhibitor of the zona pellucida-induced acrosome reaction (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 423-432 
    Details
    ISSN: 1040-452X
    Keywords: QNB ; ZP ; Sperm receptor complex ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: 3-Quinuclidinyl benzilate (QNB), a potent antagonist of muscarinic acetylcholine receptors, has been demonstrated to inhibit specifically the zona pellucida (ZP)-inducud acrosome reaction (AR) in mouse sperm (Florman and Storey, 1982; Dev Biol 91:121-130). In this study we describe the solubilization and partial purification of the mouse sperm QNB binding activity which may represent a component of the putative receptor complex for ZP on the sperm plasma membrane. Sperm membranes were isolated from cell homogenates of washed, capacitated, epididymal mouse sperm. Scatchard plots of QNB binding to these membranes indicated a single class of binding sites with KD = 7.2 nM and Bmax = 8700 sites/cell. These binding characteristics are similar to those seen with QNB binding to whole cells (Florman and Storey, 1982, J Androl 3:157-164). Sperm membranes were solubilized using 1% digitonin/0.2% cholate, and the resultant detergent-soluble fraction possessed QNB binding activity similar to that of intact membranes. The detergent-soluble fraction maintained intact ZP receptor(s)-G protein coupling in that treatment of this fraction with either ZP or mastoparan resulted in a 35% or 65% increase in specific GTPγS binding, respectively. The solubilized membrane preparation was fractionated by gel permeation HPLC. A majority of specific QNB binding activity was confined to one HPLC fraction. Analysis of this fraction by SDS-PAGE revealed a complex of approximately 5 proteins unique to this fraction. The most prominent protein had a Mr of 72 kDa, which is within the Mr range for muscarinic receptors. A protein with Mr = 41 kDa was also present within this fraction. Subsequent pertussis toxin (PTX)-catalyzed ADP-ribosylation of this fraction revealed this protein to be the α subunit of the Gi class of G proteins. Although the QNB binding activity could not be positively identified, we propose that it is contained in one or more of the proteins unique to this fraction and that these proteins, including Gi, may act as part of a sperm receptor complex for the ZP. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390411
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  • 173
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    Expression of scatter factor/hepatocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: Is scatter factor/hepatocyte growth factor involved in initiation of sperm motility? (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 431-439 
    Details
    ISSN: 1040-452X
    Keywords: Sperm ; Testis ; Scatter factor ; Hepatocyte growth factor ; Sperm motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Based upon findings that the scatter factor/hepatocyte growth factor (SF/HGF) has strong mitogenic and motogenic properties, and that the sperm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to investigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various regions of the murine male genital tract by scatter and cell tracking assays using MDCK epithelial cells, Western blot procedure, and the immunohistochemical procedure using paraffin sections of various regions of the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male genital tract with slight or no expression in the testes, caput epididymis, and vas deferens, and with the highest expression in cauda and corpus (distal) epididymis followed by expression in the corpus (proximal) epididymis. This region-specific SF/HGF expression pattern coincides with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. However, wherever SF/HGF was expressed in the male genital tract, its molecular weight was slightly higher (Mr, 82 kD), compared to the SF/HGF expressed in various other somatic tissues (Mr, 78 kD), indicating that the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Incubation of immotile sperm from caput epididymis with the purified human placental SF/HGF of 78 kD initiated motility in 5-15% of sperm population. These results strongly suggest that the SF/HGF-like activity is expressed in the male genital tract in a region-specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380411
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  • 174
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    The physiology of reproduction, 2nd edition, Two-Volume Set, Editors-in-Chief Ernst Knobil and Jimmy Neal, Raven Press, New York, 1994, 3,302 pp, $360. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 459-459 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380414
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  • 175
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    Attachment of the ascidian sperm surface egg receptor N-acetylglucosaminidase to the cell membrane (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 453-458 
    Details
    ISSN: 1040-452X
    Keywords: Ascidian sperm glycosidase ; Solubilization ; Hydrophilic ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Ascidian sperm bind to vitelline coat N-acetylglucosamine groups of the egg bvia sperm surface N-acetylglucosaminidase. This sperm surface egg receptor remains anchored throughout penetration. Localization to the sperm surface was verified by biotinylation of intact sperm followed by solubilization in Triton X-100 and binding to streptavidin agarose. The enzyme was determined to be an integral membrane protein as judged by resistance to release by KI and high pH. Linkage of the enzyme to the sperm surface was probed through differential solubilization followed by measuring released enzymatic activity with a fluorogenic substrate. Nonionic detergents released 90% of the activity. Proteases released about 40%. No activity was released by a phosphatidyl-inositol specific phospholipase C. This finding, combined with the similarity of release level by all the detergents, including triton X-114 phase separation experiment. This observation, coupled with the finding of release by nonionic detergents, suggests that the protein is hydrophilic once released from the membrane. Thus, although clearly an integral membrane protein, the enzyme has limited bydrophobicity such as would be present in a single transmembrane sequence or extensive glycosylation. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080380413
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  • 176
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    Images of science, a history of scientific illustration, by Brian Ford, Oxford University Press, New York, 1993, 208 pp, $45. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 459-459 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380416
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  • 177
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    The human brain, an introduction to its functional anatomy, 3rd edition, by John Nolte, St. Louis, 1993, 466 pp, $38.95. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 459-459 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380415
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  • 178
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    Human embryology and developmental biology, by Bruce Carlson, Mosby-Year Book, Inc., Saint Louis, 1994, 447 pp, $34.95 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 459-459 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380417
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  • 179
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390101
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  • 180
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    Molecular biology of the cell, 3rd ed., by Alberts et al., Garland Publishing, New York, 1994, 1,294 pp + glossary & index, $59.95. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 459-459 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380418
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  • 181
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    Mullerian-inhibiting substance secretion is delayed in XX sex-reversed dog embryos (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 1-7 
    Details
    ISSN: 1040-452X
    Keywords: Testis ; Ovotestis ; True hermaphrodite ; Mullerian duct ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sertoli cell secretion of Mullerian-inhibiting substance (MIS) begins shortly after testis differentiation. Mullerian ducts regress following MIS exposure during an embryonic critical period. In dogs with XX sex reversal, Mullerian ducts persist in the presence of testicular tissue. This study was conducted to determine whether MIS is present in ovotestes of XX sex-reversed embryos during the period for Mullerian duct regression in normal males. XX sex-reversed embryos and normal littermates were identified by a combination of karyotype and gonadal histology. The degree of regression in the adjacent Mullerian duct was scored. Immunohistochemical staining was used to detect MIS in the contralateral gonad. Testicular differentiation and MIS secretion were identified in XY embryos at all ages studied (35-46 days). Seminiferous tubules were not observed in gonads of embryos at risk of XX sex reversal between 35-38 days (n = 15), but were observed at 40 and 46 days (n = 3). Although positive staining for MIS was observed in ovotestes, adjacent Mullerian ducts persisted. The degree of seminiferous tubule development was reduced and MIS secretion was delayed in ovotestes, compared to normal testes. Mullerian duct persistence in this model is apparently due to an abnormality in the quantity and timing of MIS secretion during embryonic development.© 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390102
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    Structure-function studies of FGF-1: Dissociation and partial reconstitution of certain of its biological activities (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 56-61 
    Details
    ISSN: 1040-452X
    Keywords: Receptor binding ; Growth factor ; Wild-type transfectants ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We reported previously that the mitogenic activities of FGF-1 (acidic FGF) could be dissociated from its receptor-binding activities by site-directed mutagenesis of lysine 132 to a glutamic acid. Although the mutant FGF-1 protein binds to the high-affinity tyrosinekinase receptors, stimulates tyrosine-kinase activity, and promotes expression of immediate-early genes, it is not mitogenic for a variety of tested cell lines. Interestingly, the mutant FGF-1 is capable of other functions associated with the wild-type protein such as promotion of mesoderm formation in Xenopus animal caps. The mutant exhibits a reduced apparent affinity for heparin-Sepharose compared to the wild-type protein. The relationship between the reduced heparin affinity and lack of mitogenic activity of this mutant is not clear. Recent data indicates the relationship is not as simple as reduced stability of the protein. When NIH 3T3 cells are transfected with expression vectors encoding either wild-type or mutant FGF-1, a transformed phenotype can be seen in cells overexpressing the wild-type FGF-1, whereas cells overexpressing mutant FGF-1 appear normal. Analysis of lysates of these cells indicates that a tyrosine-kinase cascade, distinct from that associated with the high-affinity cell surface receptors, has been activated in the wild-type transfected cells but not in the mutant transfected cells. Although both transfected cell lines contain FGF-1 cell surface receptors as judged by crosslinking studies, the wild-type transfects are refractory to exogenous FGF-1, whereas the mutant transfectants respond normally. Together these results support an intracellular role of wild-type FGF-1 in mediating certain of its functions. In addition, they demonstrate that certain functions of the growth factor can be dissociated at the structural level. Additional mutagenesis studies have resulted in the identification of mutants with heparin-binding or mitogenic deficiencies that do not correlate as well as those of the 132 mutant. It appears that the inactivity of the lysine 132 mutant is related, in part, to cysteine 131. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390110
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    Targeted disruption of int-2 (fgf-3) causes developmental defects in the tail and inner ear (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 62-68 
    Details
    ISSN: 1040-452X
    Keywords: Embryonic stem cells ; Reporter gene ; Gene targeting ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The int-2 gene (also designated fgf-3) was originally identified because its transcription is activated by the nearby integration of mouse mammary tumor virus in virus-induced tumors. Molecular analyses have revealed that the int-2 gene produces at least four mRNAs, all of which encode a protein that has 40-50% amino acid sequence similarity with the fibroblast growth factors (FGFs). Int-2 gene expression is localized to a small number of discrete sites in the developing mouse, but has not been detected in any nonneoplastic adult tissue. The expression data and the amino acid sequence similarity with the FGFs suggested several potential roles for int-2 during normal development.To evaluate these possibilities, we initiated a genetic analysis of int-2. A gene-targeting protocol was used to generate embryonic stem (ES) cells that are heterozygous for an insertion of the neor gene into the first proteincoding exon of int-2. These cells were used to establish a line of mice that carry the gene disruption. Animals that are heterozygous for the int-2neo allele are normal and fertile. Homozygous mutants survive embryonic development and can be visually identified after 12.5 days of gestation by a short, initially dorsally curled tail. This defect is potentially due to the disruption ofint-2 expression in the primitive streak/tail bud. Most of the homozygous mutants die at orsoon after birth, but several have survived to adulthood. In addition to the tail phenotype, the surviving homozygotes show, to varying extents, symptoms characteristic of innerear abnormalities. The development of these defects could be attributed to the disruption of normal int-2 expression in the hindbrain rhombomeres thought to induce inner ear development and/or the otocyst (precursor of the inner ear) itself. Other sites of int-2 expression are not affected by the mutation. Although the tail phenotype is 100% penetrant, the inner ear phenotype caused by this mutation shows reduced penetrance and variable expressivity.A second int-2 allele was generated in ES cells by using homologous recombination to introduce a IacZ reporter gene into the int-2 locus. This allele has also been established in a line of mice. The pattern of β-galactosidase activity in carriers of the int-2lacZ allele has been examined in embryos from 8.5-14.5 days of gestation and in neonatal heads using whole mount X-gal staining. Expression of the lacZ gene mirrors the expected pattern of int-2 mRNA. Several new sites int-2 of expression not identified in the initial in situ hybridization studies of int-2 mRNA have also been identified. Compound heterozygotes (int-2neo/int-2lacZ) were found to have the same defects in tail and innerear development as homozygous int-2neo mice. After staining for β-galactosidase activity, these mutants should allow an analysis of the int-2 mutant phenotype at the cellular level. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390111
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    Transfer of nuclei from 8-cell stage mouse embryos following use of nocodazole to control the cell cycle (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 147-152 
    Details
    ISSN: 1040-452X
    Keywords: Mitosis ; Synchronization ; Mice ; Blastomere ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mouse 2-, 4-, 8-, and 16-cell embryos were exposed to nocodazole in M16 culture medium. The effect of different concentrations and exposure times on the efficiency of cell cycle synchronization and the development of the treated embyros after release from the drug was determined. The minimum effective concentration (95% of arrested nuclei) for 4-, 8-, and 16-cell embryos was 5μM nocodazole. The effect upon subsequent development of mouse embryos depended upon both the stage of development of the embryo at treatment (P 〈 0.001) and the length of exposure to nocodazole (P 〈 0.001). Exposure to any concentration of nocodazole within the range 2.5-10 μM for 12 hr caused a reduction in the proportion of embryos that formed blastocysts. As the period of exposure to 5μM nocodazole increased from 12 to 24 hr, the proportion of embryos developing to the blastocyst stage decreased. The lower proportion of embyros developing to the blastocyst stage and to term (P 〈 0.01) suggests that the more advanced stages were more susceptible to damage as a result of exposure to nocodazole. The rate of development of 4-cell embryos to blastocysts was not affected when an exposure time of 9 hr was used. Together these results show that it is possible to use nocodazole to arrest mouse embryonic cells in mitosis but that it is not appropriate to culture the embryos in the presence of this drug for prolonged periods. Individual blastomeres completed mitosis at 60-90 min and started DNA synthesis at 120-150 min after release from nocodazole. Nuclei from blastomeres thus synchronized were used to conduct studies on the effect of the cell cycle on nuclear transfer. A signficant effect was found. When nuclei from 8-cell embryos in G1 or S-phase were used as nuclei donors, development to blastocyst was respectively 27% and none. ©Wiley-Liss, Inc.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/mrd.1080390205
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    Production of germline chimeric chickens, with high transmission rate of donor-derived gametes, produced by transfer of primordial germ cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 153-161 
    Details
    ISSN: 1040-452X
    Keywords: Chick embryo ; Germline chimerism ; Transplantation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Germline chimeric chickens were produced by transfer of primordial germ cells from White Leghorn to Barred Plymouth Rock, and vice versa. Blood was collected from stage 13-15 embryos and primordial germ cells were concentrated by Ficoll density gradient centrifugation. Approximately 200 primordial germ cells were injected into the bloodstream through the dorsal aorta of stage 14-15 recipient embryos from which blood had been drawn via the dorsal aorta prior to the injection. Intact embryos were also prepared as recipients for White Leghorns only. The manipulated embryos were cultured in recipient eggshells until hatching. Germline chimerism of the chickens reaching maturity was examined by mating them with Barred Plymouth Rocks and donor-derived offspring were identified based on their feather color. The efficiency of production of germline chimeras was 95% (19/20). When primordial germ cells were transferred from White Leghorn to Barred Plymouth Rock, the average frequency of donor-derived offspring was 81% for three male chimeras (96% for one female chimera), and it was ∼3.5 times higher for transfer in the opposite direction (23% for 6 male chimeras). Removing blood from recipient embryos prior to primordial germ cell injection enhanced the frequency of donor-derived offspring by 10% in resulting male chimeras. Male chimeras produced donor-derived offspring more frequently (∼3.8 times) than female chimeras. Increases, decreases, or no changes were observed in the frequency of donor-derived offspring from the germline chimeras with increasing age. Male to female ratio of the offspring derived from the donor primordial germ cells did not deviate significantly in male and female chimeras, suggesting that primordial germ cells that have different sex from recipient embryos could not differentiate into functional gametes. The technique for primordial germ cell transfer employed in this experiment is simple to perform and resulted in the efficient production of germline chimeras with high transmission rates of donor-derived gametes. This system provides a powerful tool for avian embryo manipulation. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390206
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    Leukaemia inhibitory factor and the regulation of pre-implantation development of the mammalian embryo (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 233-238 
    Details
    ISSN: 1040-452X
    Keywords: Blastocyst ; Implantation ; Uterus ; Cytokine ; LIF ; ES Cell ; Gene knock-out ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This paper reviews the evidence that certain growth factors, particularily leukaemia inhibitory factor (LIF), play a crucial role in regulating the development of the pre-implantation mammalian embryo. LIF was originally implicated in regulating the early development of the mouse embryo because it inhibited the differentiation of embryonic stem (ES) cells, pluripotential cells derived from the inner cell mass of the blastocyst. Subsequent studies on its role in vivo revealed, surprisingly, that it is essential for the growth rather than the differentiation of the blastocyst. In vivo, overtly normal blastocysts can be produced in a LIF-deficient environment that are capable of forming viable fertile adults. However, in the absence of LIF, they fail to implant and enter into a state resembling that exhibited by blastocysts undergoing delayed implantation, which is characterized by a cessation of cell proliferation. This failure to implant occurs because the principle sites of LIF production are the endometrial glands of the uterus. These synthesize and secrete LIF at implantation, with LIF synthesis essential for implantation. Preliminary evidence indicates that LIF synthesis is required both by the uterus for it to undergo decidualization and by the blastocyst for implantation. These data indicate that the maternal environment plays a crucial role in the development and growth of the pre-implantation embryo, by supplying factors that regulate these processes in the embryo. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390217
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    Culture of animal cells, 3rd edition, by r. ian freshney, wiley-liss, new york, 1994, 486pp, $69.95 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 247-247 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390221
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994) 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390301
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    Discriminating translation of insulin-like growth factor-II (IGF-II) during mouse embryogenesis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 249-258 
    Details
    ISSN: 1040-452X
    Keywords: RNA cleavage ; Polysomes ; Imprinting ; Choroid plexus ; Leptomeninges ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The problem is to discover which of the promoters of the insulin-like growth factor-II gene stimulate the transcription of mRNA which is translated into protein. Three alternative leader exons are attached to the coding sequences in RNA transcribed from this gene in other systems, and it is mainly the paternal allele which is expressed in mouse development. Transcripts bearing each of the three leader exons were found in the RNA from the chorio-allantoic placenta, visceral yolk sac, and embryo, starting at 9.5 days. A varying proportion of one abundant transcript was disengaged from the polysomes at different days of development. This transcript was prefixed by the longest of the three alternative untranslated 5′ leader exons (exon 2), and it was consistently associated with polysomes in the choroid plexus and leptomeninges of the brain. Many exon 2 transcripts were abbreviated by endonucleolytic cleavage and lacked a poly(A) tail. In contrast, the transcripts with the shortest leader (exon 3) were mainly displayed on polysomes at all the stages of development which were examined. During mouse development, the production of IGF-II protein must be partly controlled by the mechanisms which regulate translation. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390302
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    Analysis of aspartic acid and asparagine metabolism in Xenopus laevis oocytes using a simple and sensitive HPLC method (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 392-396 
    Details
    ISSN: 1040-452X
    Keywords: Amino acids ; Asparagine ; Aspartic acid ; Oocytes ; Xenopus laevis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The amino acids in methanol-soluble extracts of Xenopus oocytes were measured using a method involving precolumn derivatization with phenylisothiocyanate and reverse phase HPLC of the derivatized amino acids. This technique allows the estimation of asparagine and glutamine pools in oocytes, estimated as 70 and 283 pmoles per oocyte, respectively. The pool sizes of the other amino acids were similar to previously reported results obtained using conventional ion exchange chromatography and postcolumn derivatization with ninhydrin. The advantages of the method developed here include picomolar sensitivity and the enhanced resolution of asparagine and glutamine from other amino acids. The kinetics of aspartic acid and asparagine utilization were monitored following microinjection of oocytes with [3H]aspartic acid and [14C]asparagine. The aspartic acid pool turned over rapidly with a half-time of 〈30 min. The asparagine pool was metabolized much more slowly and appeared to be utilized almost completely for protein synthesis. The absolute rate of protein synthesis in oocytes was calculated from the incorporation data and chemical pool measurements as ∼25 ng/hr-oocyte. The methodology developed here may be useful in experimental situations involving limited amounts of biological material. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/mrd.1080390407
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    Differential localization of two isoforms of the regulatory subunit RIIα of cAMP-dependent protein kinase in human sperm: Biochemical and cytochemical study (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 415-422 
    Details
    ISSN: 1040-452X
    Keywords: cAMP-dependent protein kinases ; Human ; Sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the present study, immunogold labeling of ultrathin sections of ejaculated sperm was used to obtain insight into the ultrastructural localization and presumable function of type II cAMP-dependent protein kinase in sperm motion. In the flagellum, a human-specific isoform of the RIIα subunit was located on the axonemal microtubule wall, whereas a different isoform of broader specificity was present in the cytoplasm at the periphery of the coarse fibers and fibrous sheath. This isoform was also found in the mitochondria. The human-specific RIIα subunit is likely linked to microtubules by a unique binding protein of Mr 72kD. These findings are in agreement with the concept of a concerted mechanism involving phosphorylation of both the axonemal microtubules and the fibrous structures for the regulation of mammalian sperm motion. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390410
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    Comparison of the ability of progesterone and heat solubilized porcine zona pellucida to initiate the porcine sperm acrosome reaction in vitro (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 433-438 
    Details
    ISSN: 1040-452X
    Keywords: Progesterone ; Porcine ; Zona pellucida ; Sperm ; Acrosome reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: It has been previously shown that progesterone can initiate the acrosome reaction (AR) of capacitated human and hamster sperm in vivo. We report here that progesterone can initiate a morphologically normal AR in porcine sperm that have undergone capacitation in a Hepes-buffered medium in vitro. In addition, we have compared the abilities of progesterone and heat-solubilized porcine zona pellucida (zona) to initiate the porcine sperm AR. Capacitated porcine sperm were treated with 1 m̈g/ml progesterone, 150 m̈g/ml porcine zona, or solvent control for 10 min. After treatment, sperm were incubated with the supravital dye Hoechst 33258, fixed and the acrosomal status determined in the previously viable sperm by fluorescence microscopy with fluorescein isothiocyanate-labeled Pisum sativum agglutini (FITC-PSA). There was no significant difference between the percentage of AR initiated by zona compared to that initiated by progesterone. In order to determine whether there was a synergistic interaction between the two AR initiators, both were added simultaneously to capacitated porcine sperm at optimal (1 m̈g/ml progesterone, 150 m̈g/ml zona) and suboptimal (75 ng/ml progesterone and 75 m̈g/ml zona) concentrations. Simultaneous addition of the two AR-initiators at the two concentrations stimulated an additive AR-initating response, rather than a synergistic one. Several possible explanations for the additive results are discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/mrd.1080390412
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    Masthead (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994) 
    Details
    ISSN: 1058-8388
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001990101
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    Cloning and developmental expression of the chick type II and type III TGFβ receptors (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 12-27 
    Details
    ISSN: 1058-8388
    Keywords: TGFβ ; TGFβ receptors ; Embryogenesis ; Organogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: To address the role of peptide growth factors in chick organogenesis, we have focused on TGFβ2 and have cloned the chick Type II and Type III TGFβ receptors. The chick Type II receptor is a serine/threonine kinase with a ligand binding profile identical to the human receptor and a divergent N-terminus when compared to the mammalian receptors. The chick Type III receptor is a betaglycan that demonstrates a binding profile identical to the rat receptor and contains a single transmembrane spanning domain and short cytoplasmic tail that are highly conserved when compared to the mammalian receptors. Both the Type II and Type III TGFβ receptors are coexpressed during chick embryogenesis in the developing heart, lung, and eye, and are developmentally upregulated in parallel in the heart and lung. Levels of both receptor proteins and mRNAs also increase in cardiocytes cultured from different developmental stages, in agreement with the increase in Type II and Type III receptor mRNA levels observed in the developing heart. Although exhibiting different temporal or spatial profiles from the receptors, TGFβ2 is also expressed in the developing heart, lung, and eye. These findings are consistent with recent data indicating that co-expression of both the Type II and Type III TGFβ receptors is required for high affinity binding of TGFβ2 by the Type II receptor and suggest that TGFβ2 and the Type II and Type III TGFβ receptors participate in heart, lung, and eye development. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/aja.1001990103
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    Pattern regulation in the chick autopodium at advanced stages of embryonic development (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 64-72 
    Details
    ISSN: 1058-8388
    Keywords: Limb morphogenesis ; Regulation ; Chondrogenesis ; Cell death ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In previous studies we have observed that the interdigital tissue of the chick embryo leg bud during the stages previous to interdigital cell death exhibits a considerable chondrogenic potentiality both in vivo and in vitro. In the present investigation we have carried out a variety of experimental manipulations of the chick leg bud at stage 29 to discover possible mechanisms accounting for interdigital ectopic chondrogenesis and extradigit formation. Our results show that the interdigital tissue is capable of forming an extradigit when temporarily isolated microsurgically and regrafted in its original loction and after deletion of one of the adjacent digital primordia, suggesting that developing phalangeal cartilages exercise an inhibitory effect on chondrification in adjoining tissues. Furthermore, and of greater importance, ablation of the primordium of a digit is followed by normal development of the definitive digit if the wound surfaces are suitably apposed. These results reveal a considerable regulatory potentital in the autopodium at advanced stages of development. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/aja.1001990107
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  • 196
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    Elastic extracellular matrix of the embryonic chick heart: An immunohistological study using laser confocal microscopy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 200 (1994), S. 321-332 
    Details
    ISSN: 1058-8388
    Keywords: Heart development ; Embryo ; Extracellular matrix ; Elastin ; Fibrillin ; Emilin ; Collagen type VI ; Myocardium ; Immunohistochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The “elastic matrix” constitutes a specialized component of the extracellular matrix which confers resiliency to tissues and organs subjected to repeated deformations. The role of the elastic matrix in living organisms appears to be of key importance since diseases characterized by expression of defective inherited genes which encode components of the elastic matrix lead to premature death. While the elastic matrix of adult organs has received a great deal of attention, little is known about when it first appears in embryonic tissues or its possible role in developing organs. In the present study we have performed an immunohistochemical study of the distribution of elastin and three additional components often associated with elastic matrices in adult tissues (i.e., fibrillin, emilin, and type VI collagen) during the development of the chicken embryonic heart. The three-dimensional arrangement of these components was established through the observation of wholemount specimens with scanning laser confocal microscopy. Our results revealed three different periods of heart development regarding the composition of the elastic matrix. Prior to stage 21 the embryonic heart lacks elastin but exhibits a matrix scaffold of fibrillin and emilin associated with the endocardium and the developing cardiac jelly. Between stages 22 and 29 the heart shows a transient elastic scaffold in the outflow tract which contains elastin, fibrillin, and emilin. Elastin-positive fibrillar material is also observed during these stages in the base of the atrioventricular cushion adjacent to the myocardial wall. In addition, emilin-positive material appears to be associated with the zones of formation of ventricular trabeculae. Collagen type VI was not detected during these early stages. From stage 30 to stage 40 a progressive modification of the pattern of distribution of elastin, fibrillin, emilin, and collagen type VI is observed in association with the formation of the definitive four-chambered heart. The distribution of the elastic scaffold in the outflow tract appears to be rearranged and becomes restricted to the roots of the main arteries. Each of the components studied here is also deposited at increasing levels in the developing valvular apparatus including the valve leaflets and the chordae tendinea. The components are also present in the subendocardial space where they form aligned fibrillar tracts, an arrangement suggestive of a role in ventricular contractile function. The epicardium constitutes an additional region of elastic matrix deposition during these later stages and contains elastic, fibrillin, and collagen type VI. Finally, during the later stages the intramyocardial matrix (“myocardial interstitium”) is formed and characterized by an abundance of collagen type VI, emilin, and fibrillin but lacks elastin-positive material. This study suggests that during cardiac development there is not a fixed composition of the so-called “elastic matrix.” Rather, combinations of the different components of the elastic matrices appear to characterize the matrix associated with specific regions of the embryonic heart and may reflect the different tensile properties required in these regions during development. Possible roles for these specific elastic matrices during heart morphogenesis are discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 31 Ill.
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    URL: http://dx.doi.org/10.1002/aja.1002000407
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    Embryonic expression patterns of the drosophila decapentaplegic gene: Separate regulatory elements control blastoderm expression and lateral ectodermal expression (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 28-44 
    Details
    ISSN: 1058-8388
    Keywords: Drosophila ; Pattern formation ; TGF-β family ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Patterns of decapentaplegic (dpp) transcripts derived from the intact gene were compared to the patterns of transcripts generated by partial dpp transgenes in Drosophila embryos. Sequences closest to the dpp coding regions, the dpp hin region, were sufficient to express lacZ-tagged mRNA in patterns indistinguishable from the patterns of endogenous dpp expression in the dorsal and terminal cells at the blastoderm stage, in the dorsal ectoderm during germ band elongation, and in narrow stripes of ectodermal cells along the dorsal edge of the ectoderm and at the boundary between the lateral and ventral neurogenic regions during germ band shortening. The latter pattern of expression responded to the segment polarity genes naked and wingless. However, these dpp sequences were not sufficient to drive lacZ-tagged mRNA expression in other cells normally expressing dpp, including cells in the gnathal segments, the clypeolabrum, the foregut, the midgut visceral mesoderm, and the hindgut. Two separate regulatory regions were found in the dpp hin region. A 479 bp region upstream of the promoter was necessary for the segmented pattern of expression in the lateral ectoderm and for expression in the midgut endoderm. Cis-acting elements in the 2 kbp second intron directed expression in the dorsal and terminal regions of the blastoderm, acted on a heterologous promoter, the P-element promoter, and responded to pattern information derived from the maternal effect dorsal/ventral patterning genes. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001990104
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  • 198
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    Expression patterns of the murine LIM class homeobox gene lim1 in the developing brain and excretory system (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 73-83 
    Details
    ISSN: 1058-8388
    Keywords: lim1 ; Homeodomain proteins ; LIM class homeobox genes ; Xlim1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We report the cloning, sequence analysis, and developmental expression pattern of lim1, a member of the LIM class homeobox gene family in the mouse. lim1 cDNA encodes a predicted 406 amino acid protein that is 93% identical with the product of the Xenopus LIM class homeobox gene Xlim1. We have characterized lim1 expression from day 8.5 post coitum onward. Northern blot analysis of RNA transcripts indicates that lim1 is expressed both during embryogenesis and in the adult brain. Analysis by whole-mount and section in situ hybridization shows lim1 expression in the central nervous system from the telencephalon through the spinal cord and in the developing excretory system including pronephric region, mesonephros, nephric duct, and metanephros. In the metanephros, lim1 is strongly expressed in renal vesicles and S-shaped bodies, and transcripts are also detected in the ureteric branches. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001990108
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  • 199
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    Forward spreading in the establishment of a vertebrate Hox expression boundary: The expression domain separates into anterior and posterior zones, and the spread occurs across implanted glass barriers (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 229-240 
    Details
    ISSN: 1058-8388
    Keywords: Chicken ; Homeobox ; Hoxd-4 ; Expression ; Primitive streak ; DiI ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: By use of wholemount in situ hybridization, we show how expression of the chicken homeobox gene Hoxd-4 commences in the posterior part of the primitive streak and then spreads forward, covering most of the primitive streak by the 2 somite stage, covering the entire primitive streak by the 5 somite stage, reaching the somite 1/somite 2 level of the neural tube by the 9 somite stage, and reaching the rhombomere 6/rhombomere 7 junction of the hindbrain by the 15 somite stage. Forward spreading does not depend upon cell migration, as was evidenced by vital dye (DiI) cell marking experiments. Furthermore, forward spreading does not apparently require tissue continuity since it could not be blocked by impermeable (glass) barriers surgically implanted to divide embryonic tissues. As forward spreading of chick Hoxd-4 proceeds, the domain of expression separates, at late primitive streak stages, into “anterior” and “posterior zones,” with an intervening “intermediate zone” of weak or non-expression. Clear anterior and posterior zones were also found for Hoxa-3 and a-4 expression in late primitive steak stage mouse embryos. We present evidence that the anterior zone corresponds with the “definitive” domain of Hox gene expression, as has earlier been extensively characterized in midgestation embryos. The posterior zone is transitory, probably persisting only for the duration of the primitive streak, and it is a region of intense Hox expression in primitive streak tissue, Hensen's node, and adjacent regions of neurectoderm and mesoderm. We suggest that the posterior zone marks the source of a morphogen which is the primary activator of Hox gene expression, and we discuss possible models for the mechanism of forward spreading in expression. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001990307
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  • 200
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    Analysis of the in vivo myogenic status of chick somites by desmin expression in vitro (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 199 (1994), S. 268-279 
    Details
    ISSN: 1058-8388
    Keywords: Desmin ; Somite ; Myogenesis ; Chick embryo ; In vitro ; Immunohistochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Expression of the muscle specific intermediate filament protein, desmin, is an early marker for chick somitic myogenesis. Somites are transient, paired, mesodermal structures adjacent to the neural tube which are formed very uniformly in a cranial to caudal fashion. The developmental somitic expression of desmin in vivo has been reported previously (Holtzer et al. [1991] “Frontiers in Muscle Research.” New York: Elsevier Science, pp 187-207; Borman and Yorde [1994] J. Histochem. Cytochem. 42:265-272). Here we explore the ability of those somitic cells which are desmin negative in vivo to successfully carry out a myogenic program of development in the absence of the surrounding embryonic microenvironment. Somites which are known to be overtly desmin negative in the embryo were explanted and cultured on collagen gels for 4 days. Immuno-detection of desmin identified a population of somites that could support desmin positive cells in vitro as well as a population of somites that could not. The cranially located somites must remain in the embryo for a greater length of time than the caudally positioned somites prior to each being able to express desmin in vitro. In embryos of many ages there is also a population of somites unable to support desmin expression in vitro. The rate at which this ability to support somitic desmin expression in vitro progresses caudally in the embryo is significantly greater than the rate at which somites form. Notably, the detected expression of desmin in somites in vitro is parallel to the rate at which overt expression of desmin in vivo is detected. The implication for these observations with regard to the regulation of somitic myogenesis is discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001990403
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