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  • 1
    Electronic Resource
    Electronic Resource
    Structure of aGelasinospora linear plasmid closely related to the kalilo plasmid ofNeurospora intermedia (1996)
    Springer
    Current genetics 29 (1996), S. 150-158 
    Details
    ISSN: 1432-0983
    Keywords: Gelasinospora ; Neurospora ; Plasmid ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have determined the complete nucleotide sequence of a linear mitochondrial plasmid from a natural isolate of a homothallic species ofGelasinospora. The plasmid genome is 8231 by long. It carries terminal inverted repeats of 1137 bp. Extending inwards from the terminal repeats are two long open reading frames coding for putative proteins with similarity to DNA and RNA polymerases. These are separated by a short intergenic region. The plasmid sequence shows remarkable similarity to that of theNeurospora intermedia senescence-plasmid kalilo. Overall the two plasmids have a similar genetic organization and are clearly homologous at the sequence level. The main differences are in the intergenic region and in the terminal repeats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02221579
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  • 2
    Electronic Resource
    Electronic Resource
    A new senescence-inducing mitochondrial linear plasmid in field-isolated Neurospora crassa strains from India (1991)
    Springer
    Current genetics 19 (1991), S. 129-137 
    Details
    ISSN: 1432-0983
    Keywords: Senescence ; Plasmid ; Neurospora ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Several field-collected strains of Neurospora crassa from the vicinity or Aarey, Bombay, India, are prone to precocious senescence and death. Analysis of one strain, Aarely-1e, demonstrated that the genetic determinants for the predisposition to senescence are maternally inherited. The senescence-prone strains contain a 7-kb, linear, mitochondrial DNA plasmid, maranhar, which is not present in long-lived isolates from the same geographical location. The maranhar plasmid has inverted terminal repeats with protein covalently bound at the 5′ termini. Molecular hybridization experiments have demonstrated no substantial DNA sequence homology between the plasmid and the normal mitochondrial (mtDNA) and nuclear genomes of long-lived strains of N. crassa. Integrated maranhar sequences were detected in the mtDNAs of two cultures derived from Aarey-1e, and mtDNAs with the insertion sequences accumulated during subculturing. Nucleotide sequence analysis of cloned fragments of the two insertion sequences demonstrates that that they are flanked by long inverted repeats of mtDNA. The senescence syndrome of the maranhar strains, and the mode of integration of the plasmid, are reminiscent of those seen in the kalilo strains of N. intermedia. Nonetheless, there is no detectable nucleotide sequence homology between the maranhar and kalilo plasmids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00326294
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  • 3
    Electronic Resource
    Electronic Resource
    Recombination between heterologous linear and circular mitochondrial plasmids in the fungus Neurospora (1995)
    Springer
    Molecular genetics and genomics 249 (1995), S. 25-36 
    Details
    ISSN: 1617-4623
    Keywords: Neurospora ; Plasmids ; Mitochondria ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A strain of Neurospora intermedia from China contains five prominent extragenomic mitochondrial plasmids: three linear elements called zhisi plasmids, and two circular plasmids, Harbin-1 and -2. In one subculture, levels of four plasmids (all three zhisis and Harbin-1) fell to undetectable values and two novel linear plasmids appeared, Harbin-L and -L2, as well as a new small circular plasmid, Harbin-0.9. Cross-hybridization of restriction fragments and DNA sequencing showed that the Harbin-L plasmid was composed of parts of the circular Harbin-1 plasmid and of one of the linear zhisi plasmids. A model is presented in which the Harbin-1 and zhisi plasmids are present within the same mitochondrion, and crossovers at two separate 7 by sites of sequence identity effectively insert part of the circular Harbin-1 DNA into a zhisi linear plasmid, simultaneously deleting part of the zhisi element. The small plasmid Harbin-0.9 is a fragment of the Har-1 plasmid, and seems to be another product of the recombination process that created Har-L. Recombination of this type could have contributed to the wide array of mitochondrial plasmids found in natural populations of Neurospora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00290232
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  • 4
    Electronic Resource
    Electronic Resource
    Plasmid diversity in senescent and nonsenescent strains of Neurospora (1993)
    Springer
    Molecular genetics and genomics 237 (1993), S. 177-186 
    Details
    ISSN: 1617-4623
    Keywords: Senescence ; Linear plasmids ; Circular plasmids ; Neurospora ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A sample of 171 natural isolates of Neurospora crassa and Neurospora intermedia was tested for senescence. Of these, 28 strains senesced within the duration of the experiment. These senescent strains, together with a selection of nonsenescent strains, were examined for the presence of mitochondrial plasmids. This was done by digesting mitochondrial DNA preparations with proteinase K, and running these samples on agarose gels. Most of the strains examined, both senescent and nonsenescent, contained plasmids, many of them new. Some new plasmids were linear, as inferred from their resistance to 5′ exonuclease and sensitivity to 3′ exonuclease. New circular plasmids were also found. Some strains carry several plasmids, and mixtures of circular and linear elements were common. A cross-homology study was performed on a sample of plasmid-bearing strains, and several cases of apparent relatedness were found, some between strains from distant geographical locations. Linear plasmids homologous to the maranhar linear senescence plasmid were quite common. A new member of the LaBelle circular plasmid homology group was found. In the sample tested for homology, no strains contained elements related to the kalilo linear senescence plasmid. The relationship of the new plasmids to senescence is not known. In addition to plasmid monomers, several different types of derivatives were found. The kalilo linear plasmid was found to occur in linear and circular forms of low mobility, presumed to be giant concatamers, and, in some strains, variant sibling structures and ladders of short derivatives were found. Circular plasmids also gave rise to extensive ladders on electrophoresis, probably representing different relaxation states and head-to-tail concatameric series. Some such forms migrated more slowly than mitochondrial DNA. One unique type of plasmid modification observed was a pair of linear elements that had apparently arisen de novo which showed homology to a circular plasmid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282799
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  • 5
    Electronic Resource
    Electronic Resource
    Sarcomeric myosin heavy chain expressed in nonmuscle cells forms thick filaments in the presence of substoichiometric amounts of light chains (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 192-204 
    Details
    ISSN: 0886-1544
    Keywords: myofibrillogenesis ; myosin heavy chain ; myosin light chains ; transfection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Central to the function of myosin is its ability to assemble into thick filaments which interact precisely and specifically with other myofibrillar proteins. We have established a novel experimental system for studying myofibrillogenesis using transient transfections of COS cells, a monkey kidney cell line. We have expressed both full-length rat α cardiac myosin heavy chain (MHC) and a truncated heavy meromyosin-like α MHC (sHMM) and shown that immunoreactive MHC proteins of the expected sizes were detected in lysates of transfected cells. Surprisingly, the full-length MHC formed large spindle-shaped structures throughout the cytoplasm of transfected cells as determined by immunofluorescence microscopy. The structures were not found in cells expressing the sHMM construct, indicating that their formation required an MHC rod. The spindle-shaped structures ranged in length from approximately 1 μm to over 20 μm in length and were birefringent suggesting that they are ordered arrays of thick filaments. This was confirmed by electron microscopic analysis of the transfected cells which revealed arrays of filamentous structures approximately 12 nm in diameter at their widest point. In addition, the vast majority of transfected MHC did not associate with the endogenous nonmuscle myosin light chains, demonstrating that myosin thick filaments can form in the absence of stoichiometric amounts of myosin light chains. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260303
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  • 6
    Electronic Resource
    Electronic Resource
    Zona drilling enhances fertilization by mouse caput epididymal sperm (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 27 (1990), S. 332-336 
    Details
    ISSN: 1040-452X
    Keywords: Caput epididymis ; Micromanipulation ; In vitro fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Spermatozoa from the caput epididymis are known to be much less capable of fertilization when compared to sperm from more distal segments of the epididymis. The purpose of this study was to determine if two micromanipulative techniques, zona drilling (ZD) and a modification of partial zona dissection (PZD), could be used to enhance fertilization with caput epididymal sperm. A mouse in vitro fertilization model was used. Inseminating oocytes with 500-1,000 sperm/oocyte from the cauda epididymis as a control resulted in fertilization of 98 of 300 (32.6%) oocytes. Of those fertilized, 47 developed to the blastocyst stage (47.9%). Caput sperm fertilized 13 of 116 (11.2%) nonmanipulated oocytes. Only 1 of 13 developed into a blastocyst, while with oocyte ZD, caput sperm fertilized 24 of 144 (16.7%) oocytes, 50% of those fertilized developing to blastocyst (P=0.0129). When modified PZD was performed on oocytes, only one of 23 was fertilized, with no blastocyst development. These results indicate that acid Tyrode ZD enhances both fertilization and early embryonal development when caput epididymal sperm are used for insemination. These mouse studies suggest that ZD or other micromanipulation techniques may prove clinically useful in men with proximal epididymal obstruction where only caput sperm are available.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080270407
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  • 7
    Electronic Resource
    Electronic Resource
    Electron microscopic studies of magnetosomes in magnetotactic bacteria (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 389-401 
    Details
    ISSN: 1059-910X
    Keywords: Biomineralization ; Greigite ; Magnetite ; Pyrite ; Single-magnetic-domain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron microscopic studies on magnetosomes in magnetotactic bacteria have revealed much information on their composition, structure, and even the formation of their mineral phase. The mineral phases of the magnetosomes are of two general types: iron oxides and iron sulfides. Iron oxide-type magnetosomes contain particles of the ferrimagnetic mineral magnetite (Fe3O4) while the iron sulfide-type contain ferrimagnetic greigite (Fe3S4), greigite and non-magnetic pyrite (FeS2), or possibly ferrimagnetic pyrrhotite (Fe7S8). Regardless of their composition, the crystalline particles in magnetosomes have a narrow size range: approximately 35 to 120 nm. Magnetite crystals in this size range are single-magnetic-domains and confer a permanent magnetic dipole moment to the cell. The single-domain size range for greigite is not known but is probably similar to that for magnetite.The morphology of the particles in the bacterial magnetosomes appears to be species-specific. Morphologies of magnetite crystals in different species of magnetotactic bacteria include cubooctahedra, parallelepipedal (truncated hexahedral or octahedral prisms), and tooth- or bullet-shaped (anisotropic). Morphologies of greigite particles include cubo-octahedra and rectangular prismatic. The greigite-pyrite particles are generally pleomorphic with no consistent crystalline morphology. A membrane has been shown to surround the particles in some organisms and may be involved in the formation of the crystalline phase while also providing physical constraints on the size and the shape of the crystal. These results clearly indicate that the biomineralization process involved in the bacterial magnetosome, a good example of a self-assembled structure on a nanometer scale, is highly controlled by the organism. © 1994 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070270505
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  • 8
    Electronic Resource
    Electronic Resource
    Osteocranial development in the viviparous surfperch Amphistichus argenteus (pisces: Embiotocidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 95-120 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of the cranial and branchial skeleton of the surfperch Amphistichus argenteus, a member of the family Embiotocidae, is described, and phylogenetic and functional aspects of the skull development of this species are discussed. The earliest bones to appear are those dermal elements of the branchial skeleton involved with feeding, and the bones, both dermal and endochondral, located in the basicranial region of the neurocranium. These are followed by dermal bones associated with the lateral line system and finally by the remainder of the bones of the branchial skeleton and the cartilaginous bones of the otic capsules. The last bone to develop is the ethmoid.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051740108
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  • 9
    Electronic Resource
    Electronic Resource
    The sudanophilic lipid of normal and regenerating limb tissues of the adult newt, Diemictylus viridescensThis investigation was supported by a Public Health Service research grant GM06208 from the National Institute of General Medical Sciences. (1966)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 57-77 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The most intense and widely distributed sudanophilic responses of cryostat-sectioned newt limb tissues were obtained with a simultaneous fix and stain procedure of 1:1 10% formal-calcium and sudan black B. Droplets and globules of lipid mixtures and rodlets (mitochondria) were typical responses distributed within the epidermis, subcutaneous glands, dermis and other connective tissues, striated muscle (also with positive fibrils), tunics of blood vessels, and blood cells. A prominent droplet response was located subjacent to the adepidermal basement membrane. The myelin of brachial nerve stained intensely.In regenerating limbs, the wound epithelium response was comparable to that of epidermis. Post-amputational lipophanerosis of injured muscle and brachial nerves was observed. The retrograde degeneration of nerve myelin was extensive, and continued into the early differentiative phase of regeneration. Lipid-engorged macrophages were prominent among the injured tissues, distal to these, and within the wound epithelium.The regeneration blastema revealed a large quantity of sudanophilic lipid. Prominent droplet and rodlet responses were typical of the myelinating regenerating nerves. The response of regenerating muscle equaled that of the mature stump fibers. The cells of the regenerating chondroskeleton contained sudanophilic lipid.Organic solvents such as acetone, ether, chloroform and chloroform:methanol reduced or prevented the sudanophilic responses. Sudan red 7B revealed less lipid than did sudan black B. A fixation effect was demonstrated with post-chromated formalcalcium, and chromic-formalin fixed sections. In the latter preparations, swollen-bodies, identified as mitochondria, stained intensely.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051180105
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  • 10
    Electronic Resource
    Electronic Resource
    The fine structure of tissues in the amputated-regenerating limb of the adult newt, Diemictylus viridescensThis investigation was supported by a research grant GM 06208, and a graduate training grant 8T1-HD-16, from the Public Health Service. (1967)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 123 (1967), S. 271-311 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the fine structure of injured, repairing and regenerating tissues of the amputated forelimbs of the adult newt: observations were made on wound epithelium, nerves, striated muscle, the regeneration blastema, connective tissues and cartilage.The wound epithelium shows little modulation from the adjacent epidermis: a subjacent glycocalyx and hemidesmosomes are initially absent. Some cells reveal phagocytic activity. As regeneration progresses, a glycocalyx, hemidesmosomes, and an adepidermal reticulum of fibers develop.Nerve fiber degeneration and regeneration lie side by side in the same nerve bundle. Myelin degeneration is evident within 24 hours; neural connective tissues loosen and fibers appear to spread apart.Striated muscle fibers display a nonuniform response to trauma, due to unequal degree of injury inflicted by amputation. The moderately and greatly injured fibers lose their distal fibril organization. There is a numerical increase in mitochondria, and occasionally a pyknotic nucleus is present. The myofiber glycocalyx appears to resist destruction, even when cell degeneration is extensive. Satellite cells have been observed intimately in contact with injured myofibers. Myogenesis is accompanied by an increase in collagen fibrillogenesis associated with adjacent fibroblasts. Many of these latter cells appear to contain intracellular fibrils: the significance of these observations are discussed, and a basis for intracellular fibrillogenesis and tropocollagen accretion is proposed.The fine structure of the regeneration blastema cell agrees with the description offered by others for the adult newt limb regeneration.Early prochondral condensation of blastema cells is described briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051230306
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