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  • 1990-1994  (3,440)
  • 1935-1939
  • 1990  (3,440)
  • Cell & Developmental Biology  (1,448)
  • Analytical Chemistry and Spectroscopy  (1,434)
  • Engineering  (558)
  • Nuclear reactions
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  • 1990-1994  (3,440)
  • 1935-1939
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Vasculature of the head and respiratory organs in an obligate air-breathing fish, the swamp eel Monopterus (=Amphipnous) cuchia (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 203 (1990), S. 181-201 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Methyl methacrylate vascular corrosion replicas were used to examine the macrocirculation in the head region and the microcirculation of respiratory vessels in the air-breathing swamp eel Monopterus cuchia. Fixed respiratory tissue was also examined by SEM to verify capillary orientation. The respiratory and systemic circulations are only partially separated, presumably resulting in supply of mixed oxygenated and venous blood to the tissues. A long ventral aorta gives rise directly to the coronary and hypobranchial arteries. Two large shunt vessels connect the ventral aorta to the dorsal aorta, whereas the remaining ventral aortic flow goes to the respiratory islets and gills. Only two pairs of vestigial gill arches remain, equivalent to the second and third arches, yet five pairs of aortic arches were identified. Most aortic arches supply the respiratory islets. Respiratory islet capillaries are tightly coiled spirals with only a fraction of their total length in contact with the respiratory epithelium. Valve-like endothelial cells delimit the capillary spirals and are unlike endothelial cells in other vertebrates. The gills are highly modified in that the lamellae are reduced to a single-channel capillary with a characteristic three-dimensional zig-zag pathway. There are no arterio-arterial lamellar shunts, although the afferent branchial artery supplying the gill arches also supplies respiratory islets distally. A modified interlamellar filamental vasculature is present in gill tissue but absent or greatly reduced in the respiratory islets. The macro- and micro-circulatory systems of M. cuchia have been considerably modified presumably to accommodate aerial respiration. Some of these modifications involve retention of primitive vessel types, whereas others, especially in the microcirculation, incorporate new architectural designs some of whose functions are not readily apparent.
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052030206
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  • 102
    Electronic Resource
    Electronic Resource
    Extrusion of the residual body in spermatids of Ancylostoma caninum (nematoda, strongyloidea) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 203 (1990), S. 283-292 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transmission electron microscopy reveals that the spermatocytes of the hookworm Ancylostoma caninum contain an abundance of Golgi complexes, ribosomes, specialized membranous organelles, and long strands of smooth endoplasmic reticulum. These organelles remain abundant until the early spermatid stage of sperm development, when they reach their maximum abundance and maturity and the production of new ones ceases. Golgi complexes, ribosomes, and excess SER, which are not functional after this stage, become segregated and confined to the posterior portion of the spermatid in a polar lobe. Later, the polar lobe together with excess cytoplasmic matrix is bound by a membrane and dissociated from the spermatid as a residual body. The spermatid is then devoid of Golgi complexes and ribosomes. Formation of residual bodies as sperm cells mature may be considered a type of cell excretion.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052030303
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  • 103
    Electronic Resource
    Electronic Resource
    Golgi study of the anterior dorsal ventricular ridge in a lizard. II. Neuronal cytodifferentiation (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 203 (1990), S. 301-310 
    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 morphologic features of neurons in the anterior dorsal ventricular ridge (ADVR) has been followed in Golgi preparations from the lizard Gallotia galloti between embryonic stage 32 and post-eclosion stages of specimens 3.6-4.5 cm in length. The differentiation sequence of multipolar and bitufted neurons was established. Dendritic growth cones are present after stage 34. Filiform dendritic processes are replaced later on by spines. Clusters of neurons first appear at stage 39 in the periventricular zone, the cells becoming Golgi-impregnated in pairs. After hatching, the number of impregnated cells per cluster increases.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052030305
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  • 104
    Electronic Resource
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    Lectin histochemistry of the hyaline layer in the asteroid, pisaster ochraceus (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 203 (1990), S. 361-375 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Six different lectins were used to study the carbohydrate nature of the hyaline layer (HL), the external extracellular matrix of the starfish embryo. Thin sections of embryos fixed in the late gastrula stage were incubated with five fluoresceinated lectins: Con A, WGA, RCA, UEA-I, and SBA. All but UEA-I labelled the HL, suggesting that the following sugars are present: mannose and/or glucose, glcNAc and/or Neu5Ac, galactose, and galNAc. The different lectins produced variable degrees of labelling, with WGA, RCA, and SBA producing more intense labelling than Con A. Binding of lectins by the HL was studied at the ultrastructural level by exposing ultrathin sections to the following lectin-gold conjugates: Con A, WGA, PNA, SBA, and LFA. Lectin binding was observed over the various regions of the HL, recognized by Crawford and Abed (J. Morphol. 176:235-246, '86), i.e., the intervillus layer, the supporting layer and the coarse outer meshwork. Local differences in labelling patterns were observed among the various lectins, with SBA labelling all regions intensely, WGA and PNA labelling the supporting layer predominantly, and Con A labelling the HL only lightly. No labelling was observed with LFA. These lectin-labelling patterns in the HL demonstrate the presence of different glycoconjugates in different regions of the HL, suggesting that the layers differ biochemically. The existence of biochemical differences strengthens the idea that each layer may have different functions in the developing starfish embryo.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052030310
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  • 105
    Electronic Resource
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    Development and evolution of the carotid circulation in geomyoid rodents in relationship to their craniomorphology (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 33-45 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The diversity in cranial morphology of living geomyoids, including pocket gophers (Thomomys), spiny pocket mice (Heteromys and Liomys), desert pocket mice (Chaetodipus and Perognathus), and kangaroo rats and mice (Dipodomys and Microdipodops) is accompanied by only a few differences in their cephalic arterial circulation. The principal difference is the origin of the pterygopalatine artery, which serves the orbit and rostrum. In dipodomyines and perognathines it originates as a stapedial branch of the internal carotid artery and passes through the middle ear en route to the braincase. In geomyines and heteromyines it originates as an internal maxillary branch of the external carotid artery and enters the braincase directly. Either geomyines and heteromyines are convergent in this respect, or the currently recognized family Heteromyidae is paraphyletic. The stapedial artery is the same size in early embryos of T. bottae and D. merriami, but in the former species it fails to grow and disappears in juveniles. Comparison of developmental series of D. merriami and T. bottae revealed that the decline of the artery in the latter species is preceded by a greater degree of arterial coarctation, or narrowing, as it passes though the developing stapes. The loss of the stapedial artery is correlated with an enlarged masseter profundus muscle in T. bottae and with an unusually small stapes in T. bottae, H. desmarestianus, and L. salvini. I hypothesize that the primitive condition for geomyoids is the presence of both stapedial and internal maxillary arteries, that the stapedial artery was lost in geomyines and heteromyines because of the constraint on its size posed by the stapes, and that the stapedial artery was retained in dipodomyines because enlargement of the stapes accompanied bullar inflation in these taxa and lifted the constraint on the size of the stapedial artery.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040105
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  • 106
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    The digestive system of the fish ectoparasite Dolops ranarum (Crustacea: Branchiura) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 103-112 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reconstructions from serial sections reveal that the digestive system consists of a pharynx esophagus, crop, midgut, and rectum. Two main stems from the branched enteral diverticula are connected to the lateral regions of the crop by right rind left arms. Glandular tissue surrounds the enteral diverticula proximally. A strong sphincter separates the crop and midgut, whereas the midgut and rectum are separated by a weak sphincter. Cuboidal epithelium lines the pharynx, esophagus, crop, and rectum, whereas cuboidal and club-shaped epithelia line the midgut. The cuboidal cells possess elongated nuclei and numerous vacuoles, suggesting that absorption takes place in the midgut.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040111
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  • 107
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    Videofluorographic analysis of tongue movement in the rabbit (Oryctolagus cuniculus) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 139-146 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The movement of the entire tongue and intermolar eminence during mastication is described in the domestic rabbit (Oryctolagus cuniculus). Tongue movement and jaw position were analyzed videofiuorographically from separate lateral and dorso-ventral views in six rabbits. Metallic markers were inserted into the tongue so that its movement was visible on the fluorographic image. Frame-by-frame analysis of the videofluorographic tape recordings demonstrates that tongue movement in all animals was identical in direction during each part of the chewing cycle. In the lateral view the forepart of the tongue moves down and forward during the opening stroke, whereas the intermolar eminence moves up and forward to appose the palate. During the closing stroke, as the tip of the tongue moves up and back, the intermolar eminence lowers from the palate and retracts. During the power stroke the forepart of the tongue is at its most elevated and retruded position, while the intermolar eminence is its lowest and most retruded. The dorso-ventral view showed that lateral movement of the tongue and mandible are highly synchronous. The intermolar eminence decreases in width during the power stroke, possibly twisting to place or keep food on the teeth. An anterior to posterior undulating movement of the entire tongue occurs throughout the chewing cycle. As the intermolar eminence elevates to appose the palate during the opening stroke, it may replace the bolus on the teeth on the chewing side. The intermolar eminence also appears to be twisting during the closing and power strokes to place or maintain food on the teeth.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040203
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  • 108
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    Structure of the kidney in the crab-eating frog, Rana cancrivora (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 147-156 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of the nephron in the ranid frog, Rana cancrivora, was studied by light and electron microscopy. This frog is the only amphibian species to live in mangrove swamps of very high salinity. The nephron consists of the following parts: renal corpuscle, ciliated neck segment, proximal tubule, ciliated intermediate segment, distal tubule, connecting tubule, and collecting duct. The distal tubule is located in the ventromedial region of the kidney, and the other tubules are situated in the dorsolateral region. Renal corpuscles are found between the two regions. Some renal corpuscles have a wide Bowman's space because of the small glomerulus within them. The proximal tubules are composed of columnar cells with a dense luminal brush border of long microvilli and numerous apical vesicles and vacuoles. The initial part of the distal tubule consists of heavily interdigitated cells, characterized by a very regular palisade arrangement of mitochondria. In the terminal part of the distal tubule, shorter mitochondria of the infolding cells are situated irregularly around the nucleus. The connecting tubule consists of principal cells and canaliculus cells. The collecting duct consists of columnar or cuboidal cells; cytoplasmic organelles are relatively sparse. The canaliculus cells are intercalated between principal cells from the terminal distal tubule to the proximal part of the collecting duct. Our findings indicate that the kidney of R. cancrivora is structurally similar to kidneys of other amphibians. These findings are discussed with regard to probable correlations between ultrastructure and function in R. cancrivora.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040204
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  • 109
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    Morphological changes in the oocyte and its surrounding vestments during in vivo fertilization in the dasyurid marsupial sminthopsis crassicaudata (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 177-196 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This light and transmission electron microscopical study shows that the first polar body is given off before ovulation and that part of its cell membrane and that of the surrounding oocyte have long microvilli at the time of its ejection. Several layers of cumulus cells initially surround the secondary oocyte and first polar body, but the ovulated oocytes in the oviducts in the process of being fertilized do not have cumulus cells around them. Partly expelled second polar bodies occur in the oviduct; they are elongated structures that lack organelles and have electron-dense nuclei. A small fertilization cone appears to form around the sperm tail at the time of sperm entry into the egg and an incorporation cone develops around the sperm head in the egg cytoplasm. In three fertilized eggs a small hole was seen in the zona, which was presumably formed by the spermatozoon during penetration. Cortical granules, present in ovarian oocytes, are not seen in fertilized tubal or uterine eggs; release of their contents probably reduces the chances of polyspermy, although at least one polyspermic fertilized egg was seen and several other fertilized eggs had spermatozoa within the zona pellucida. In the zygote the pronuclei come to lie close together, but there was no evidence of fusion. A “yolk mass,” which becomes eccentric before ovulation, is extruded by the time the two-cell embryos are formed, but many vacuoles remain in the non-yolky pole of the egg. A shell membrane of variable thickness is present around all uterine eggs but its origin remains undetermined.
    Additional Material: 51 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040207
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  • 110
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    Ultrastructure and organization of circumventricular organs and endolymphatic tubules in the treefrog, Hyla versicolor (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 197-208 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology and anatomical relationship of the paraphysis, anterior choroid plexus, and endolymphatic tubules of Hyla versicolor suggest that these structures may act as a functional unit to regulate composition of the cerebrospinal fluid (CSF). Ependymal cells of both the paraphysis and the choroid plexus exhibit ultrastructural features (an extensive microvillar border, large intercellular spaces containing an amorphous material, and apically located mitochondria) which indicate active exchange between the blood and CSF. Mast cells (which may play a role in regulating vascular permeability) also occur on the brush border. The tubules of the endolymphatic sacs were found to lie in close relation with the dorsal portion of the paraphysis. The endolymphatic organ is known to play a role in systemic buffering during respiratory acidosis and may influence Na/K fluxes via calcium release. The association of the paraphysis with the endolymphatic tubules may therefore represent an important mechanism for ion regulation in the CSF of amphibians. The ultrastructure of the pineal organ agrees with descriptions for other species. No pineal stalk was present. Photoreceptor inner and outer segments project into a central lumen continuous with the third ventricle. Outer segments show signs of disorganization. Photoreceptor/neural dendrite contacts involve synaptic ribbons and conventional synapses.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040208
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  • 111
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    Ultrastructure of the maxillary gland of Asellus aquaticus (crustacea, isopoda) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 281-293 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Asellus aquaticus is a freshwater isopod with an unusually long excretory duct of the maxillary gland. The ultrastructure of this gland is described in detail for the first time. Only one comparable description of an isopod excretory gland has been published until now (for a marine species). The gland is composed of an end sac (coelomosac) with podocytes which allow passive ultrafiltration by haemolymph pressure. The podocytes resorb material (probably proteins) from the primary urine. The opening to the excretory duct is controlled by a valve, which consists of muscular sphincter cells and larger valve cells; the latter protrude into the duct. The ultrastructure of cells in different regions of the excretory duct and of the terminal duct is described and correlated with the possible function of the organ.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040306
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  • 112
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    Golgi study of the anterior dorsal ventricular ridge in a lizard. I. neuronal typology in the adult (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 203 (1990), S. 293-300 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using Golgi techniques we have studied neuronal cell types in the anterior dorsal ventricular ridge (ADVR) of the adult lizard Gallotia galloti. Multipolar, bitufted, and juxtaependymal neuronal forms were found. The multipolar and bitufted neurons are present in both the periventricular and central ADVR zones. Multipolar neurons can be subdivided into multipolar neurons with polygonal somata and four to six main dendritic trunks and multipolar neurons with pyramidal somata and three or more dendritic trunks. The former are the cells most frequently impregnated in the ADVR. In the population of bitufted neurons, we distinguish subtypes I, II, and III according to the number of dendritic trunks that emerge from the somata. Juxtaependymal neurons are restricted to a cell-poor zone, adjacent to ependymal cells. Their dendrites either are orientated parallel to the ventricular surface or extend into the periventricular zone. The dendrites of ADVR neurons have pedunculated spines with knob-like tips. However, such spines do not appear on the somata or on the primary dendritic trunks. The number of spines is scarce or moderate. The periventricular neuronal clusters contain two to five cells. The morphology of these neurons is mainly multipolar, but we also found some bitufted neurons.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052030304
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  • 113
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    Changes in lectin-binding pattern in the digestive tract of Xenopus laevis during metamorphosis. II. Small intestine (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 205 (1990), S. 9-15 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The binding of seven lectins (concanavalin A, Con A; Dolichos biflorus agglutinin, DBA; peanut agglutinin, PNA; Ricinus communis agglutinin I, RCA-I; soybean agglutinin, SBA; Ulex europeus agglutinin, UEA-I; and wheat germ agglutinin, WGA) to the small intestine in metamorphosing Xenopus laevis was studied by the avidin-biotin-peroxidase (ABC) method. The staining pattern of the epithelium with all lectins except for UEA-I and Con A changed gradually during metamorphic climax; the main component of the epithelium, absorptive cells, gradually became positive for DBA, PNA, and SBA and the scattered goblet cells for RCA-I and WGA. On the other hand, the change of the staining pattern in the connective tissue occurred only for Con A, RCA-I, and WGA, and this change took place rapidly at the beginning of climax (stage 60). Increased staining for Con A and WGA at stage 60 was observed only in a group of connective tissue cells close to the epithelium and in the basement membrane. As metamorphosis progressed, this localization of the staining intensity became less clear. At the completion of metamorphosis (stage 66), the absorptive cells were stained with all lectins except for UEA-I, whereas the goblet cells stained only with RCA-I and WGA. These results indicate that lectin histochemistry can distinguish between larval and adult cells of both two epithelial types (absorptive and goblet cells). The technique may also identify a group of connective tissue cells, close to the epithelium, that possibly induce the metamorphic epithelial changes.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052050103
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  • 114
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    Amputation level-dependent patterning in urodele limb regeneration (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 205 (1990), S. 77-84 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Comparison of mesopodial skeletal patterns found in native and regenerated limbs of the salamander Plethodon cinereus reveals variant patterns unique to each group. Variant patterns in native limbs are based on fusions between laterally adjacent elements (i.e., in the anteroposterior axis). Variant patterns in the mesopodia of regenerated limbs usually exhibit fusions among proximodistally adjacent elements. Analysis of regenerates derived from limb amputation at different levels shows that the axis of fusion between regenerated mesopodial elements remains the same (i.e., proximodistal) independent of amputation level. However, the frequency of specific fusion combinations is unexpectedly sensitive to amputation level. Proximal (stylopodial) amputation results in mesopodial patterns with predominantly preaxial fusion combinations; distal amputation produces mesopodial patterns with predominantly postaxial fusion combinations. This finding is discussed in the context of other recent studies in which amputation level influenced limb regeneration patterning.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052050108
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  • 115
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    Neuronal typology of the thalamic area triangularis of Gallotia galloti (reptilia, sauria) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 205 (1990), S. 113-121 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a Golgi study of the area triangularis (AT), a rostral nucleus of the ventral thalamus of Gallotia galloti, we have identified four major neuronal types on the basis of their morphological characteristics: medium-sized fusiforms with two processes, medium-sized fusiforms with three or four processes, small bipolars, and small and medium-sized multipolars. These neurons are characterized by a simple morphology and radial arrangement. Cell size varies from small to medium, and all axons project laterally. These characteristics distinguish AT neurons from those of neighboring nuclei. In addition, we found some evidence of differential topographic distribution of each neuronal type within the nucleus. Medium-sized fusiform neurons with two processes are located in the most ventral part, where they constitute the ventral nuclear limit. Small multipolar neurons prevail in the dorsal and ventromedial parts, and in the rest of the nucleus medium-sized neurons, including both fusiform with three or four processes and multipolar types, are normally found. Finally, we discuss a putative homology of the reptilian AT with a part of the mammalian zona incerta.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052050111
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  • 116
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    Ultrastructure of the mouth apparatus in Branchiobdella pentodonta (annelida, clitellata) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 171-176 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mouth apparatus in Branchiobdella pentodonta was studied by electron microscopy. The opening is situated dorsal to the adhesive disk of the anterior sucker and is surrounded by a ring of 16 papillae. The papillae have mono-layered epithelium, muscle fibers, glandular processes, and taste and olfactory organs like “sensitive buttons.” The oral cavity contains jaws with horny teeth and “sensitive buttons,” and is surrounded by a ring of circular muscle fibers that connect to the muscle fiber of the papillae. This apparatus shows some analogies to that of Hirudinea, such as the presence of sucker and jaws with horny teeth.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040206
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  • 117
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    Ultrastructure of the blood vessels in the harderian gland of the hamster (mesocricetus auratus): Existence of sinusoids (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 257-263 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Harderian gland blood supply of female and male hamsters was studied using light and electron microscopy. A profuse vascularization surrounding secretory acini was observed. Among the blood vessels, the existence of large and irregular sinusoidal capillaries was apparent. These sinusoids appeared in close association to the basal aspect of the secretory cells. Typical, small, fenestrated capillaries were also observed within the connective tissue. The existence of this particular vascularization together with other morphological features of the secretory cell basal pole suggest a possible endocrine function of these orbital glands.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052040304
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    Fine structural observations on the process of spermiation in the holocephalan fish Hydrolagus colliei (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 295-304 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The process of spermiation in the ratfish Hydrolagus colliei is described and compared with that in mammals and amphibians. Spermiation in this species involves prior fluid space expansion both within the apical parts of the Sertoli cytoplasm and in the spaces between Sertoli cells and spermatids. The apical ends of Sertoli cells fragment, including the parts immediately around the spermatid acrosomes. Intercellular material between the spermatid tips and the Sertoli cells dissolves. Concurrently an opening from the seminiferous follicle into the efferent ductule is made by means of changes in cell shape and separation of Sertoli cells and efferent ductule cells that adhere to each other up to the time of sperm release.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052040307
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    The ultrastructure of the compound eye of Munida rugosa (Crustacea: Anomura) and pigment migration during light and dark adaptation (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 205 (1990), S. 243-253 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The galatheid squat lobster, Munida rugosa, has compound eyes of the reflecting superposition type in which a distal cone cell layer and a proximal rhabdom layer are separated by an extensive clear zone. The eye is shown to have certain unique features. In all other reflecting superposition eyes, the clear zone is traversed by crystalline tracts formed by the cone cells. In M. rugosa a thin distal rhabdom thread, formed by the eighth retinula cell, connects the cones to the proximal fusiform rhabdoms. The cytoplasm of the other retinula cells also crosses the clear zone in a complex pattern. Fully light-adapted ommatidia are optically isolated by limited migrations of distal shielding pigments. A reflecting pigment multilayer lines each cone to facilitate the formation of a superposition image. This also shows a light-induced change which may limit the acceptance angle of the eye during light adaptation.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052050302
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    Structure of the scales of Dermophis and Microcaecilia (Amphibia: Gymnophiona), and a comparison to dermal ossifications of other vertebrates (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 25-43 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structures of the dermal scales and the cells surrounding the scales in two species of gymnophione amphibians were studied using histochemistry and light, scanning and transmission electron microscopy. Scales are composed of a basal platt of several layers of unmineralized collagenous fibers topped with mineralized squamulae. Squamulae are composed of numerous mineralized globules and mineralized, thick collagen fibers. Mineralization is therefore both spheritic and inotropic. Isolated flattened cells lie on the outer surface of the squamulae and seem to be involved in mineral deposition. Cells that line the basal plate synthesize the collagenous stroma of the plate. Each scale lies in a thin connective tissue pocket, and a large connective tissue pouch includes several scales in each annulus.The similarities of gymnophione scales to elasmoid scales of osteichthyans are largely superficial. Aspects of mineralization and of pocket development differ considerably. There are also similarities, as well as differences, in the gymnophione scales and osteoderms of amphibians and of reptiles. We consider that such dermal structures have arisen many times in diverse lineages of vertebrates, and that these are expressions of properties of dermal collagen to support mineralization by specialized dermal cells. However, we recommend that the term “dermal scale” be used for the mineralized dermal units of osteichthyans and gymnophiones, and “osteoderm” for the dermal structures of frogs and squamates, with the understanding that the terminology recognizes certain convergent attributes of shape and structure, but not of process.
    Additional Material: 36 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060104
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    Innervation pattern of the gill arches and gills of the carp (Cyprinus carpio) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 71-78 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The innervation pattern of the respiratory gill arches of the carp (Cyprinus carpio) is described. The gill region is innervated by the branchial branches of the glossopharyngeal and vagal nerves. Each branchial nerve divides at the level of or just distal to the epibranchial ganglion into: 1) a pretrematic branch, 2) a dorsal pharyngeal branch, and 3) a posttrematic branch. The dorsal pharyngeal branch innervates the palatal organ in the roof of the buccal cavity. The pretrematic and posttrematic branches innervate the posterior and anterior halves, respectively, of the gill arches bordering a gill slit. Each branch splits into an internal and an external part. The internal bundle innervates the buccal side of the gill arch, including the gill rakers. The external bundle terminates in the gill filaments. The epibranchial motor branch, a small nerve bundle containing only motor fibers, circumvents the ganglion and anastomoses distally with the posttrematic branch. The detailed course and branching patterns of these branches are described.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060108
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    Observations and comments on the reliability of muscle reconstruction in fossil vertebrates (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 109-117 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In Canis and Ursus the largest proportion of attachments of muscles of the shoulder and brachium on the scapula and humerus is direct; fewer attachments are aponeurotic or tendinous. In both genera most attachments can be associated with superficial osteological features (scars or delimitable surfaces); attachments that lack such features are direct. Most aponeurotic attachments are associated with rugose scarring whereas tendinous attachments are often associated with smooth surfaces. Although most attachments can be associated with osteological features the areal extent of attachment is often not inferrable from the bone. The inference of muscle size or functional significance from osteological features is problematic. The amount of myological information that can be deciphered from the osteology in Canis and Ursus is greater than that reported for particular members of other vertebrate groups which suggests that there may be differences in the degree to which muscles can be reconstructed from superficial osteology alone. Nonetheless, even in mammals such as the Carnivora, detailed muscular reconstructions in extinct taxa cannot be achieved without reference to the musculature of extant relatives. Such reconstructions rely on assumptions, that often have not been adequately tested, regarding the similarity of musculature in closely related taxa. This testing and well corroborated hypotheses of phylogenetic relationship are essential for the evaluation of the accuracy of reconstructions of the musculature in fossil vertebrates.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1052060111
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    Changes in the arrangement of the extracellular matrix, larval shape, and mesenchyme cell migration during asteroid larval development (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 147-161 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When fixed in the presence of alcian blue, extracellular matrix (ECM) in the embryonic asteroid blastocoel can be visualized by light and electron microscopy as a fibrous meshwork encrusted with alcianophilic material. In early to mid-gastrulae, the ECM is associated with the basal laminae underlying the ectoderm and endoderm. It also forms a fibrous meshwork between them in the posterior part of the blastocoel. In early larvae, when mesenchyme cells arrive at the esophagus to differentiate into smooth muscle, very little ECM is associated with the stomach region. In contrast, a meshwork of long ECM strands radiates from the esophageal basal lamina which connects to a dense ECM web associated with the inner aspect of the dorsal ectoderm. This dorsal web is associated, in turn, with numerous long ECM strands which run parallel to the stomodeum. The strands located between the esophagus and the ectoderm appear when the mouth and coeloms form and may be responsible for a constriction of the ectoderm that forms in this region. During late gastrula one population of mesenchyme cells becomes associated with the esophageal region and differentiates into muscle. Most of the other mesenchyme cells stop migrating through the esophageal web at this time. Less alcianophilic material is associated with the esophageal basal lamina, and the ECM adjacent to the esophagus in the late gastrula and early bipinnaria larvae. The arrangement of the ECM elements suggests that they could be involved in controlling the migration of mesenchyme cells, particularly those destined for the esophagus.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060202
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    Tunic cords, glomerulocytes, and eosinophilic bodies in a styelid ascidian, Polyandrocarpa misakiensis (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 197-210 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Some unusual specialized structures of the tunic and epidermis in Polyandrocarpa misakiensis were studied histologically, histochemically, and electron microscopically. The tunic is leathery, containing fibers. Dorsal epidermal cells show cytoplasmic bulges at their apical ends, suggesting formation of tunic by the epidermis. Both siphons are characterized by a well-developed velum. In the dorsal mantle, especially around the siphons, numerous elongate cord-like structures of the tunic (10-30 μm in diameter) extend into the hemocoel. Each tunic cord originates from the extra-epidermal tunic, ends distally in a spade-shaped swelling, and is covered by flattened epidermal cells. The tunic cords probably act as connectors between tunic and mantle. Glomerulocytes, a kind of blood cell, are distributed throughout the hemocoel. They are disc-shaped (12-13 μm in diameter, 3 μm thick), and are characterized by a concentric fiber structure in the cytoplasm. The intracellular fibers are similar to the tunic fibers both morphologically and histochemically. The glomerulocytes appear to be derived from epidermal cells; their differentiation occurs in all regions of the epidermis. The function of glomerulocytes is unknown. Small club-shaped bodies which are intensely eosinophilic are distributed here and there in the dorsal epidermis. These eosinophilic bodies are usually located individually in epidermal pockets, and are protruded into the hemocoel. The eosinophilic body is proteinaceous and PAS-positive; it may be a secretory product of the covering epidermis. No physiological role of the eosinophilic body is yet clear. During blasto-genesis, incipient tunic cords, glomerulocytes, and eosinophilic bodies appear almost simultaneously at a stage shortly before the opening of siphons.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060206
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    Functional morphology of dewlap extension in the lizard Anolis equestris (Iguanidae) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 245-258 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dewlap is an extendible flap of skin ordinarily folded under the throat. Lizards, particularly those in the genus Anolis, extend their dewlaps during interactions with conspecifics, other lizards, and potential predators. Dewlap extension is effected by movements of elements of the hyoid apparatus. This paper describes the anatomy of the hyoid and associated musculature in Anolis equestris, a large arboreal lizard with a prominent dewlap. A mechanism for dewlap extension is proposed based on results of morphological and experimental techniques.Specializations of the hyoid skeleton for dewlap extension include elongated second ceratobranchials and highly movable joints between the ceratohyals and the hypohyals and between the first ceratobranchials and the body of the hyoid. A well developed M. ceratohyoideus extends between the ceratohyals and the first ceratobranchials of the hyoid apparatus. During dewlap extension, the hyoid apparatus acts as a first order lever. Contraction of M. ceratohyoideus pulls the ceratohyals posterorly causing the hypohyals and the body of the hyoid to rotate dorsally around the first ceratobranchial/body joints. This movement results in the second ceratobranchials swinging forward and down, unfolding the dewlap. The relative immobility of the first ceratobranchials provides stability to the hyoid apparatus during dewlap extension. A comparison is made of dewlap extension and other hyoid displays.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060210
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    Structure of the spleen of the sea bass (Dicentrarchus labrax): A light and electron microscopic study (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 273-281 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spleen of sea bass (Dicentrarchus labrax) is composed mainly of red pulp, whereas the white pulp is poorly developed. The red pulp consists of clear reticular cells intermingled with blood cells, sinusoids, and melanomacrophage centers (MMCs). The MMCs are enclosed by an interrupted connective tissue capsule and show some areas in continuity with the adjacent pulp. The MMCs are formed by the association of free macrophages that have phagocytosed some blood cells. Sparse white pulp is diffuse, forming a cuff around the pulp arteries and MMCs, or occurring in small groups between the splenic cords. A longitudinal artery and vein, lying side by side, extend the length of the spleen. Frequently the capillaries are surrounded by a sheath of macrophages or ellipsoids. These macrophages may contain erythrocytes in varying degrees of degradation. Lymphopoiesis and plasmapoiesis occur in the sparse lymphold areas. Abundant plasma cell groups may indicate the presence of antibody production.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060304
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    The behavior of pharyngeal outer epithelial cells during regeneration of the planarian Dugesia japonica japonica (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 313-325 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The behavior of the nuclei of pharyngeal outer epithelial cells was observed by electron microscopy during regeneration of head fragments of planaria transected at the prepharyngeal region. On the fourth day of regeneration, the surface cells of the pharyngeal rudiment show some evidence of differentiation: septate desmosomes and immature rod-shaped bodies. These cells then develop many cilia and a few microvilli on their free surfaces, and the electron-density of their karyoplasm and cytoplasm increases. The basal cytoplasmic processes of the surface cells protrude into the intercellular spaces between underlying cells. Each elongated nucleus goes down into one of these processes. Two types of nuclear descent are observed. The first type occurs when the basal lamina has not yet formed under the epithelial cells. The second type occurs when the basal lamina has already developed under the epithelial cells. Many microtubules are seen running along the long axis of the cells with descending nuclei. Fine fibrous bodies are frequently observed in the descending nuclei of the epithelial cells. Intercellular substances with moderate electron-density are observed sporadically in the spaces between descending cytoplasmic processes and surrounding cells. Glycogen granules accumulate in large numbers in the basal cytoplasm in the vicinity of the descended nucleus. The mechanism of the descent of the perikarya of the pharyngeal outer epithelial cells is discussed in terms of these results.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060308
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    Interfiber tension transmission in series-fibered muscles of the cat hindlimb (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 351-361 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Several muscles of the cat hindlimb, including biceps femoris and tenuissimus, are composed of short, in-series muscle fibers with tapered intrafascicular terminations. Tension generation and transmission within such muscles requires that active fibers should be mechanically coupled in series via myomyous junctions, specialized connective tissue attachments, or the endomysium. This report establishes that the tapered fibers of the cat biceps femoris and tenuissimus muscles have insignificant numbers of either myomyous or specialized connective tissue junctions. Tension appears to be transmitted in a distributed manner across the plasmalemma of the tapered (and probably the non-tapered) portions of the fibers to the connective tissue of the endomysium, which is therefore an essential series elastic element in these muscles. Subplasmalemmal dense plaques were identified and may play a role in transmembrane force transmission. In addition to the endomysium, passive muscle fibers may also serve to transmit tension between active fibers, and therefore should also be considered to be series elastic elements.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060312
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    Announcement (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 363-363 
    Details
    ISSN: 0362-2525
    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/jmor.1052060313
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990) 
    Details
    ISSN: 0362-2525
    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/jmor.1052040101
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    Morphology of the dorsal vessel in the abdomen of the blood-feeding insect rhodnius prolixus (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 9-23 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dorsal vessel (DV) in the abdomen of the blood-feeding insect Rhodnius prolixus was divided functionally into two regions, the heart, into which haemolymph entered the DV through four pairs of ostia located in abdominal segment VII, and the aorta, along which the haemolymph was propelled from abdominal segment VI to the thorax. Osmium-fixed whole mounts revealed the DV to consist of spirally arranged striated muscle fibers and to possess two rows of ventrally attached longitudinal fibers extending the length of the abdomen. Seven pairs of alary muscles were found attached to the DV in the posterior abdominal segments. Contractions of the alary muscles attached to the ventral surface of abdominal segments VII and VIII served to expand the heart. Electron microscopy revealed the DV to consist of a thin layer of contractile elements surrounded by an inner (intima) and outer (adventitia) connective tissue layer. Embedded in the intima along each lateral side of the DV were two large groups of endocardial cells extending the length of the DV. A small group of pericardial cells was embedded in the adventitia along the mid-ventral side of the DV, and clusters of pericardial cells were found attached to the alary muscles. Nerve terminals were found only on the heart: they contained agranular synaptic vesicles approximately 30 nm in diameter and densely stained granules approximately 100-120 nm in diameter. These structural components are discussed in relation to the role of the DV in circulation.
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    URL: http://dx.doi.org/10.1002/jmor.1052040103
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    The chiton gill: Ultrastructure in Chiton olivaceus (Mollusca, Polyplacophora)Dedecated to Prof. M. Renner on the occasion of his 70th birthday. (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 75-87 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gills of Chiton olivaceus, a primitive mollusc, are relatively simple in their structure and ultrastructure but are well adapted to a life in the intertidal zone. In contrast to some other molluscs, there is no differentiation of the gill epithelium into functional regions other than respiratory ones. Ciliation of the epithelium in certain areas may optimize water flow from the outer to the inner part of the mantle cavity. The hemolymph sinuses are oriented so that hemolymph flows in the opposite direction. Interstitial cells link epithelial cells with nerve endings. Muscle cells as well as the collagenous matrix in the connective tissue differ within the main gill axis and the lateral lamellae. The life cycle of immunoactive cells within the connective tissue and the hemolymph is described.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052040109
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    Metamorphosis of cranial design in tiger salamanders (Ambystoma tigrinum): A morphometric analysis of ontogenetic change (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 121-137 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: While ontogenetic analyses of skull development have contributed to our understanding of phylogenetic patterns in vertebrates, there are few studies of taxa that undergo a relatively discrete and rapid change in morphology during development (metamorphosis). Morphological changes occurring in the head at metamorphosis in tiger salamanders (Ambystoma tigrinum) were quantified by a morphometric analysis of cranial osteology and myology to document patterns of change during metamorphosis. We employed a cross-sectional analysis using a sample of larvae just prior to metamorphosis and a sample of transformed individuals just after metamorphosis, as well as larvae undergoing metamorphosis. There were no differences in external size of the head among the larval and transformed samples. The hyobranchial apparatus showed many dramatic changes at metamorphosis, including shortening of ceratobranchial 1 and the basibranchial. The subarcualis rectus muscle increased greatly in length at metamorphosis, as did hypobranchial length and internasal distance. A truss analysis of dorsal skull shape showed that at metamorphosis the snout becomes wider, the maxillary and squamosal triangles rotate posteromedially, and the neurocranium shortens (while maintaining its width), resulting in an overall decrease in skull length at metamorphosis.These morphometric differences are interpreted in light of recent data on the functional morphology of feeding in salamanders. Morphological reorganization of the hyobranchial apparatus and shape changes in the skull are related to the acquisition of a novel terrestrial feeding mode (tongue projection) at metamorphosis. Metamorphic changes (both internal and external) that can be used to judge metamorphic condition are discussed.
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    Differential scaling of the long bones in the terrestrial carnivora and other mammals (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 157-169 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We measured the lengths and diameters of four long bones from 118 terrestrial carnivoran species using museum specimens. Though intrafamilial regressions scaled linearly, nearly all intraordinal regressions scaled non-linearly. The observed non-linear scaling of bone dimensions within this order results from a systematic decrease in intrafamilial allometric slope with increasing body size. A change in limb posture (more upright in larger species) to maintain similar peak bone stresses may allow the nearly isometric scaling of skeletal dimensions observed in smaller sized mammals (below about 100 kg). However, strong positive allometry is consistently observed in a number of large terrestrial mammals (the largest Carnivora, the large Bovidae, and the Ceratomorpha). This suggests that the capacity to compensate for size increases through alteration of limb posture is limited in extremely large-sized mammals, such that radical changes in bone shape are required to maintain similar levels of peak bone stress.
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    URL: http://dx.doi.org/10.1002/jmor.1052040205
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990) 
    Details
    ISSN: 0362-2525
    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/jmor.1052060201
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    Ultrastructure of introvert and pharynx of Halicryptus spinulosus (priapulida) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 163-171 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The introvert of Halicryptus spinulosus bears three kinds of sensilla: buccal papillae, ordinary scalids, and dentoscalids. They are all characterized by bipolar monociliary receptor cells. The former two have apical openings at which the sensory cilia are in close contact with the ambient sea water. The pharyngeal teeth are composed of slender epithelial cells the tips of which are devoid of organelles and a thick cuticle. The anatomy of the muscle arrangement of the pharynx is described. Glands occur at the junction of the pharynx and midgut.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060203
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    The relationship of book lung and tracheal systems in the spider family uloboridae (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 211-216 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The book lung surface areas of representatives of six genera were measured and divided by spider prosomal and leg mass and by the product of prosomal length and width to obtain two indexes of book lung area. Both indexes are greatest in species that have the simplest tracheal systems and smallest in those with the most extensive tracheal systems. When species are ordered phylogenetically and the lung area indexes of their hypothetical ancestors computed, a transformational increase in lung area is indicated. Neither the lung area of a species nor its phylogenetic position is significantly related to the general moisture regime of its habitat. The number of leaves in a book lung is positively correlated with both spider size and total lung area. However, leaf number is not correlated with tracheal development and shows no transformational change.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060207
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    Control of gastropod shell form via apertural growth rates (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 259-264 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper discusses and corrects ideas in Løvtrup and Løvtrup (J. Morphol. 197:53-62, '88) on how differential growth rates around the aperture cause the gastropod shell to coil at particular angles. The relationship between position relative to the shell apex and growth rate is derived. This lets us understand what information on relative growth rates around the aperture is sufficient to determine the shape of the logarithmic spiral that these growth rates generate. I argue that differential growth rates could not be physiologically controlled precisely enough to regulate apical angle; they passively follow, not actively direct, shell shape.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060302
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    Venom apparatus and toxicity of the centipede Ethmostigmus rubripes (Chilopoda, Scolopendridae) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 303-312 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The venom apparatus of Ethmostigmus rubripes, a generalized predator, consists of the telopodites of the postcephalic segment, the basal article of which contains the venom gland. Within the gland, venom granules are concentrated in intracellular secretory granules, from which they are discharged into vacuoles in the cytoplasm of the secretory cells and thereafter by exocytosis into the lumen of the gland. A venom duct carries venom to the venom claw, which introduces it into prey via a subterminal pore on the outer curvature of the claw. Pits containing pegs, presumed to be sensory, are concentrated near grooves leading to a cutting ridge proximal to the point of the claw. The venom is toxic both to mammals and insects.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060307
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    Endothelial cells of the meningeal capillaries in the rainbow trout: A freeze-fracture study (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 327-332 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Meningeal capillaries are unfenestrated. They are made up of endothelial cells that have a pinocytotic caveolae density of 41 ± 11/μm2 and 89 ± 21/μm2 on the abluminal and luminal sides respectively. The total density of intramembrane particles is not significantly different between the luminal and the abluminal membranes; however, the coefficients of partition are significantly different (P〈 0.001). One or two strands of tight junctions occur between adjacent cells but no gap junctions nor desmosomes exist. The density of nuclear pores is less than 3.2/μm2. An abundance of intermediate filaments and free vesicles, some of which are seriated, characterize the cytoplasm. The functional significance of these findings is discussed.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052060309
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  • 141
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    Purification and characterization of an 85 kDa talin-binding fragment of vinculin (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 41-50 
    Details
    ISSN: 0886-1544
    Keywords: adhesion plaques ; cytoskeletal interactions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vinculin and talin are adhesion plaque proteins which have been shown to interact with each other in vitro. In order to begin to investigate where the talin-binding domain is in vinculin, vinculin was digested with Staphylococcus aureus V8 protease to generate two major fragments of 85 and 30 kDa, and these fragments were purified. Nitrocellulose overlays with 125I-talin and the 125I-85 kDa vinculin fragment and sucrose density gradient centrifugation demonstrated that the talin-binding domain was localized to the 85 kDa vinculin fragment. Quantification of 125I-talin binding in the overlays showed that four times more talin bound to the 85 kDa fragment as compared to intact vinculin. Competitive immunoprecipitation experiments demonstrated that unlabeled 85 kDa fragment, was about three fold more effective at competing for 125I-85 kDa binding to talin than was unlabeled vinculin. These results suggest that the 30 kDa fragment inhibits the vinculin-talin interaction even though the talin-binding domain is localized in the 85 kDa fragment.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150107
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    Epidermal growth factor induces the accumulation of calpactin II on the cell surface during membrane ruffling (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 34-40 
    Details
    ISSN: 0886-1544
    Keywords: rat liver cells ; immunoprecipitation ; immunocytochemistry ; membrane-bound proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Confluent and proliferatively quiescent T51B rat liver epithelial cells provide a cellular model for the study of epidermal growth factor (EGF) effects in non-neoplastic cells. Immunoreactive calpactin II, a well-known substrate for EGF-receptor kinase, was found predominantly in the cytosol, although a second im-munoreactive pool was found in a Triton X-100-extractable membrane fraction. Stimulation with EGF resulted in a rapid and transient (2-;5 min) formation of ruffles at the cell surface and at the cell-cell contacts. Both calpactin II and filamentous actin were found co-localized at the membrane ruffles. Immunopre-cipitations of membrane-bound calpactin II from 32P-labeled cells indicate a transient EGF-dependent phosphorylation of calpactin II correlating with membrane ruffling. These results suggest a temporal (2-5 min) function for calpactin II at the plasma membrane during the EGF-induced mitogenesis of T51B cells.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150106
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  • 143
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    Flagellar photoresponses of Chlamydomonas cells held on micropipettes: I. Change in flagellar beat frequency (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 162-167 
    Details
    ISSN: 0886-1544
    Keywords: high-speed microcinematography ; photophobic response ; phototaxis ; blue light effect ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chlamydomonas cells immobilized on micropipettes were filmed at high-speed (500 f/s) while photostimulated either by one continuous light stimulus or by pulsed light in the frequency range of cell rotation (1 or 2 Hz). Two kinds of photophobic step-up and two kinds of photophobic step-down beat frequency changes without a reversal of flagellar beat were observed after frame-by-frame evaluation of 141 records. So far, a single step-up response, the “shock” response, has been considered the only photophobic response. However, the present results show that the cells always responded to step-up as well as to step-down light stimuli. Either a decrease of beat frequency by step-up was combined with an increase by step-down (type I), or an increase by step-up was combined with a decrease by step-down (type II). Whether type I or type II was observed depended on the preirradiation of the cells. All four responses are blue-light responses with a lag-time of ∼40 ms. Nothing can be said about the photoreceptor site. Regardless, these responses cannot be the basic mechanism for phototaxis, as assumed till now, because the flagella remain synchronized during the flagella beat frequency changes. Even if they are uncoupled before and after stimulation, both flagella respond in the same sense, i.e., either both increase or both decrease their beat frequency. The behavioral relevance of these responses for Chlamydomonas is not yet clear.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150305
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    Heterogeneity of microtubules in dividing sea urchin eggs revealed by immunofluorescence microscopy: Spindle microtubules are composed of tubulin isotypes different from those of astral microtubules (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 239-250 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; mitotic apparatus ; monoclonal antibodies ; sand dollar egg ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The heterogeneity of mitotic microtubules in dividing sea urchin eggs was investigated by indirect immunofluorescence using five anti-α-tubulin (YL1/2, DM1A, E3B8, D2D6, and 6-11B-1) and two anti-β-tubulin (E6B6 and DM1B) antibodies. These antibodies were divided into four classes in regard to the different immunofluorescent staining patterns: class I, which strongly stained both the spindle and aster (YL1/2, DM1A, E3B8 and E6B6); class II, which strongly stained the spindle but weakly stained the aster (D2D6); class III, which stained only the aster (DM1B); and class IV, which did not stain the mitotic apparatus (6-11B-1). These results suggest that tubulin isotypes are distributed differently in the sea urchin mitotic microtubules and that α-tubulin isotype(s) recognized by D2D6 is (are) localized mainly in spindle microtubules, whereas β-tubulin isotype(s) recognized by DM1B is (are) found only in astral microtubules.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970160404
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    Actin and actin-binding proteins in yeast (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 7-11 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150103
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  • 146
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    Assembly of the brush border cytoskeleton: Changes in the distribution of microvillar core proteins during enterocyte differentiation in adult chicken intestine (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 12-22 
    Details
    ISSN: 0886-1544
    Keywords: villin ; fimbrin ; myosin I ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The assembly of the intestinal microvillus Cytoskeleton was examined during the differentiation of enterocytes along the crypt-villus axis in adult chicken duodenum using light and electron microscopic immunolocalization techniques. Using antibodies reactive with villin, fimbrin, and the heavy chain (he) of brush border (BB) myosin I (110K-calmodulin complex) and rhodamine-conjugated phalloidin as a probe for F-actin, we determined that while actin, villin, and fimbrin were all localized apically along the entire axis, BB myosin I (he) did not assume this localization until the crypt-villus transition zone. In addition to their localization at the BB surface, all four proteins were present at significant levels along the lateral margins of enterocytes along the entire crypt-villus axis, suggesting that these proteins may be involved in the organization and function of the basolateral membrane Cytoskeleton as well. The pattern of expression of the microvillar coreproteins along the crypt-villus axis in the adult was comparable to that seen in the intestine of the late stage chicken embryo and suggests that a common program for brush border assembly may be used in both modes of enterocyte differentiation.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150104
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    Announcement (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 142-142 
    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.970170209
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  • 148
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    Effects of brain microtubule-associated proteins on microtubule dynamics and the nucleating activity of centrosomes (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 88-98 
    Details
    ISSN: 0886-1544
    Keywords: tau ; MAP2 ; dynamic instability ; microtubule nucleation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this paper, we report on the effect of brain microtubule-associated proteins (MAPs) on the dynamic instability of microtubules as well as on the nucleation activity of purified centrosomes. Under our experimental conditions, tau and MAP2 have similar effects on microtubule nucleation and dynamic instability. Tau increases the apparent elongation rate of microtubules in proportion to its molar ratio to tubulin, and we present evidence indicating that this is due to a reduction of microtubule instability rather than to an increase of the on rate of tubulin subunits at the end of growing microtubules. Increasing the molar ratio of tau over tubulin leads also to an increase in the average number of microtubules nucleated percentrosome. This number remains constant with time. This suggests that the number of centrosome-nucleated microtubules at steady state can be determined by factors that are not necessarily irreversibly bound to centrosomes but, rather, affect the dynamic properties of microtubules.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150205
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  • 149
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    Reorganization of cortical actin microfilaments and microtubules at preprophase and mitosis in wheat root-tip cells: A double label immunofluorescence study (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 76-87 
    Details
    ISSN: 0886-1544
    Keywords: antiactin ; cytochalasin B ; plant cytoskeleton ; tubulin ; oryzalin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Following our recent description [McCurdy et al.: Protoplasma. 147:204-206, 1988] of arrays of transverse cortical microfilaments (MFs) in preprophase roottip cells of wheat (Triticum aestivum L. cv. Kite), we have performed double label immunofluorescence microscopy to correlate the formation of these arrays with the known rearrangement of cortical microtubules (MTs) that occurs during preprophase. At early preprophase, indicated by a broad (i.e., young) preprophase band (PPB) of MTs, actin MFs are transverse only in the central region of the cell cortex. By late preprophase, however, cells that possess a mature (i.e., narrow) PPB of MTs have arrays of transverse MFs that occupy the entire cortical surface of the cell. Thus, apart from the PPB zone, the transverse MFs in these arrays do not colocalize with transverse cortical MTs. Depolymerization of MTs using the herbicide oryzalin does not effect the arrays of cortical MFs; however, experiments using cytochalasin B in combination with oryzalin indicate that cellular MTs are necessary for the formation of the arrays of transverse cortical MFs. The arrays of cortical MFs disintegrate during prophase into short fragments of random, filamentous actin. This situation persists until the completion of cytokinesis. The absence of MFs during mitosis in densely-cytoplasmic meristematic cells of wheat root tips indicates that filamentous actin may not have a universal function in plant cell division. The possible function of the arrays of cortical MFs in preprophase cells is discussed.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970150204
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990) 
    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.970150301
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    Motion of individual human spermatozoa, both normal and lacking the outer dynein arms, during a continuous temperature rise (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 22-32 
    Details
    ISSN: 0886-1544
    Keywords: image analysis ; sperm cell ; tracking ; motility ; velocity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of increasing temperature from 22-25°C to 37°C on various motion characteristics of individual normal human spermatozoa and spermatozoa lacking the outer dynein arms (LODA) was studied by using a new automatic microscopic tracking method. It was found that: (1) The curvilinear velocity (Vc, measured between 1-3 sec) of both normal and LODA spermatozoia, fluctuated more or less intensely between spermatozoa; this fluctuation was not thermodependent. (2) The average Vc in the two groups of spermatozoa increased with the rise in temperature at a similar rate (1μm/sec/°C), but LODA spermatozoa had an initial Vc lower than that of normal spermatozoa (12.5 ± 5.3 μm/sec and 34.2 ± 8.2 μm/sec, respectively). (3) The profile of the Vc increase associated with the temperature rise was different for the two groups of spermatozoa: for LODA spermatozoa it was linear between 25-37°C, whereas for normal spermatozoa a plateau was reached at about 31°C. (4) Various patterns of trajectory were found for both normal and LODA spermatozoa; these patterns were unrelated to temperature. However, LODA spermatozoa had more linear trajectories than normal spermatozoa. (5) Plots derived from reaction rate theory showed that the activation enthalpy, δH
    Additional Material: 9 Ill.
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    Announcement (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 88-88 
    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.970160111
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  • 153
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    T-1, a mitotic arrester, alters centrosome configurations in fertilized sea urchin eggs (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 146-154 
    Details
    ISSN: 0886-1544
    Keywords: sea urchin ; centrosome ; immunofluorescence microscopy ; barrel-shaped spindle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: T-1 induces modifications in the shape of the centrosome at division in fertilized eggs of the North American sea urchin, Lytechinus pictus. Phase contrast microscopy observations of mitotic apparatus isolated from T-1treated (1.7-8.5μM) eggs at first division shows that the centrosomes already begin to spread or to separate by prophase and that the mitotic spindle is barrel-shaped. When eggs are fertilized with sperm that have been pretreated with T-1, the centrosomes become flattened; the spindles are of normal length. Immunofluorescence microscopy using an anti-centrosomal monoclonal antibody reveals that T-l modifies the structure of the centrosome so that barrel-shaped spindles with broad centrosomes are observed at metaphase, rather than the expected focused poles and fusiform spindle. Higher concentrations of T-l induce fragmentation of centrosomes, causing abnormal accumulation of microtubules in polar regions. These results indicate that T-l directly alters centrosomal configuration from a compact structure to a flattened or a spread structure. T-l can be classified as a new category of mitotic drugs that may prove valuable in dissecting the molecular nature of centrosomes.
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    URL: http://dx.doi.org/10.1002/cm.970160208
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  • 154
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990) 
    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.970160301
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  • 155
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    Diversity of plant actins (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 164-166 
    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.970160303
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  • 156
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    Effects of trypsin and low Ca2+ on zonulae adhaerentes between chick retinal pigment epithelial cells in organ culture (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 46-58 
    Details
    ISSN: 0886-1544
    Keywords: circumferential microfilament bundles ; intercellular adhesion ; cytoskeleton ; junctional complex ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The junctional complexes in chick retinal pigment epithelial (RPE) cells in situ contain unusually large zonulae adhaerentes (ZAs) composed of subunits termed zonula adhaerens complexes (ZACs). To determine whether the properties of the ZAs differ between RPE cells which contain ZACs, and MDCK cells which lack ZACs, we investi-gated the effects of treatment with trypsin and/or low Ca2+ by transmission electron microscopy and staining for F-actin. Treatment of RPE cells for 1 h with trypsin alone has no apparent effect on the morphology of the ZA in either MDCK or RPE cells. In contrast to the ZAs in MDCK cells, which split after 3 min in low Ca2+, the ZAs in chick RPE cells stay intact even after 2 h, although the intermembrane discs, i.e., the extracellular components of the ZACs, are no longer visible. After 30 min of treatment with trypsin and low Ca2+, the ZAs split in both cell types. The CMBs start to contract, translocate toward the cell interior, and eventually disappear. This process continues even when the RPE cells are returned to normal medium. New ZAs, composed of ZACs, form between RPE cells 3 h after return to normal medium. These findings suggest that the ZACs in the ZAs of RPE cells are not directly responsible for the increase in resistance to low Ca2+. They also show that the ZA-junctions in RPE cells are not only structurally different from those previously examined, but also behave differently in response to experimental manipulation.
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    URL: http://dx.doi.org/10.1002/cm.970170107
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    Ca/Ba/Sr-induced conformational changes of ciliary axonemes (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 187-196 
    Details
    ISSN: 0886-1544
    Keywords: axonemal shape changes ; Ca/Ba/Sr ; macrocilia ; Beroë ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Macrocilia of the ctenophore Beroë undergo Ca/Ba/Sr-dependent activation of ciliary beating and microtubule sliding disintegration [Tamm, J. Comp. Physiol. A163:23-31. 1988a: Tamm, Cell Motil. Cytoskeleton 11:126-138, 1988b; Tamm, Cell Motil. Cytoskeleton 12:104-112, 1989: Tamm and Tamm, Proc. Natl. Acad. Sci. U.S.A. 86:6987-6991, 1989]. Here we report that detergent-extracted macrocilia show an ATP-independent conformational change in response to high concentrations of Ca. Ba. or Sr ions. When applied locally by iontophoresis, these ions induce a rapid planar curvature of the distal end of the macrociliary shaft, followed by a slower relaxation to the rest position. Tip curling occurs in a direction opposite to the physiological Ca/Ba/Sr response. When applied uniformly in the bath, a threshold concentration of 10-1 M Sr is required to induce curling of the tip, and the distal ends remain curved. Calmodulin antagonists do not inhibit the tip curling response.Previous workers found that Ca induces changes in the helical shape of isolated doublet microtubules [Miki-Noumura and Kamiya, Exp. Cell Res. 97:451-453, 1976: Miki-Noumura and Kamiya. J. Cell Biol. 81:355-360, 1979; Takasaki and Miki-Noumura. J. Mol. Biol. 158:317-324, 1982] and sperm axonemes [Okuno and Brokaw, Cell Motil. 1:349-362. 1981] and suggested that conformational changes in microtubules may play a role in Ca regulation of ciliary motility. We propose that the Ca/Ba/Sr-induced curling of the macrociliary tip is due to similar helical changes of doublet microtubules, some of which in macrocilia are prevented from sliding by permanent connections (compartmenting lamellae) between adjacent axonemes within the shaft. Although the tip curling response does not appear to be directly relevant to the physiological Ca response of macrocilia, it provides a novel system for investigating Ca-induced conformational changes of microtubules independent of dynein-powered active sliding.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170306
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    Yeast myosin heavy chain mutant: Maintenance of the cell type specific budding pattern and the normal deposition of chitin and cell wall components requires an intact myosin heavy chain gene (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 301-308 
    Details
    ISSN: 0886-1544
    Keywords: yeast ; myosin ; budding ; cell wall ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Recent studies with myosin heavy chain mutants in the slime mold Dictyostelium discoideum and the yeast Saccharoymyces cerevisiae indicate that the myosin heavy chain gene is not essential for cell survival under laboratory growth conditions. However, cells lacking a normal myosin heavy chain gene demonstrate substantial alterations in growth and cell division. In this study, we report that a disruption mutant in the rod portion of the yeast myosin heavy chain gene, MYOl, produces abnormal chitin distribution and cell wall organization at the mother-bud neck in a high proportion of dividing cells. It is suggested that this phenotype is the cause of the cell division defect and the osmotic sensitivity of yeast MYOl mutants. In the absence of a normal MYOl polypeptide, yeast cells alter their cell type specific budding pattern. It is concluded that an intact myosin heavy chain gene is required to maintain the cell type specific budding pattern and the correct localization and deposition of chitin and cell wall components during cell growth and division.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170405
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  • 159
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    Cell motility and the cytoskeleton video supplement 2. Video tape contents (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 356-372 
    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.970170410
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  • 160
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    Transmembrane assemblage of the photoreceptor connecting cilium and motile cilium transition zone contain a common immunologic epitope (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 329-344 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; glycoconjugates ; axoneme ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The photoreceptor connecting cilium bears a unique transmembrane assemblage which stably links cell surface glycoconjugates with the underlying axonemal cytoskeleton. Structural similarities between the photoreceptor connecting cilium and the transition zone of motile cilia suggests that this assemblage may also be present in motile cilia. Using a subcellular fraction enriched in detergent-extracted photoreceptor axonemes, three high molecular mass glycoconjugates (425, 600, and 700 kD) were previously identified as potential components of the assemblage. Through oligosaccharide characterization and binding of a specific monoclonal antibody, we have verified the localization of the 425 kD glycoconjugate to the transmembrane assemblage. Binding of the lectin peanut agglutinin (PNA) to the 425 kD glycoconjugate on nitrocellulose blots, and to isolated detergentextracted axonemes, was assessed following treatment with the enzymes neuraminidase and O-glycanase. Changes in binding to the 425 kD glycoconjugate precisely paralleled changes in binding to intact axonemes, supporting the hypothesis that the 425 kD glycoconjugate is a component of the transmembrane assemblage. Furthermore, the results suggest that the 425 kD glycoconjugate contains sialated galactose-N-acetylgalactosamine oligosaccharides which are Olinked to the protein backbone. To directly assess the distribution of the 425 kD glycoconjugate, we produced a monoclonal antibody directed against this glycoconjugate. The antibody, K26, recognizes only the 425 kD on transblots of the axoneme fraction. K26 immunoreactivity of intact axonemes is identical to that seen by PNA staining. K26 staining of isolated photoreceptors and whole retina is uniquely localized to the region of the connecting cilium. Thus, in the photoreceptor, the 425 kD is not only a component of the transmembrane assemblage but is also completely restricted to the connecting cilium.Based on morphological similarities, the photoreceptor connecting cilium is thought to be homologous to the transition zone of the motile cilium. As such, we have stained oviduct epithelium with the K26 monoclonal antibody. Immunoreactivity is restricted to the region of the transition zone at the base of motile cilia. This demonstrates that the photoreceptor connecting cilium and motile cilium transition zone are immunologically related.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170408
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    Dynamic changes of microtubule and actin structures in CV-1 cells during electrofusion (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 345-355 
    Details
    ISSN: 0886-1544
    Keywords: cell fusion ; polykaryon ; cytoskeleton ; F-actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To study the involvement of the cytoskeletal system in the fusion of animal cells, we examined the dynamic changes of cytoskeletal proteins during the various stages of cell fusion. CV-l cells were fused by applying a radio-frequency electrical pulse. Structural changes of microtubules (MTs) and F-actin were monitored simultaneously by double-label fluorescence microscopy. It was observed that in a few minutes after the initiation of cell fusion, MT bundles began to extend into the cytoplasmic bridges which were formed by fusing the membranes of neighboring cells. Later, a network of parallel MT bundles appeared between the adjacent nuclei of the fusing cells; such MT bundles may provide the mechanical links that are responsible for nuclear aggregation. The structural changes of Factin during cell fusion were more complicated. We observed many different patterns of actin distribution in the fusing cells, including some giant, ring-shaped structures. Reorganization of actin is unlikely to be involved in the nuclear aggregation process. Instead, actin bundles condensed at the cell edges may help to widen the cytoplasmic bridges to allow merging of cellular contents between the fusing cells.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170409
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    The cytoskeletal system of mammalian primitive erythrocytes: Studies in developing marsupials (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 133-145 
    Details
    ISSN: 0886-1544
    Keywords: marsupials ; mammals ; primitive erythrocytes ; nucleated erythrocytes ; marginal bands ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Seeking to resolve conflicting literature on cytoskeletal structure in mammalian “primitive” generation erythrocytes, we have utilized the circulating blood of developing marsupials. In young of the Tammar Wallaby (Macropus eugenii) and the Gray Short-tailed Opossum (Monodelphis domestica), relatively large, nucleated primitive erythrocytes constituted nearly 100% of the circulating population of birth (= day 0) and in fetuses (Tammar) several days before birth. These cells were discoidal or elliptical, and flattened except for a nuclear bulge. Their cytoskeletal system, consisting of a marginal band of microtubules enclosed within a cell surface-associated network (membrane skeleton), closely resembled that of non-mammalian vertebrate erythocytes. By day 2 or 3, much smaller anucleate erythrocytes of “definitive” morphology, lacking marginal bands, appeared in abundance. These accounted for 〉90% of the circulating population of both species by day 6-8. Non-nucleated erythrocytes of a different type, constituting 1-6% of the cells in most blood samples up to day 7, were identified as anucleate primitives on the basis of size, shape, and presence of a marginal band. Thus, loss of erythrocyte nuclei in mammals appears to begin earlier than generally recognized, i.e., in the primitive generation. Counts of these anucleate primitives in young of various ages implicated nucleated primitives as their probable source. Pointed erythrocytes, occasionally found in younger neonates of both species, occurred in greatest number in fetuses (Tammar) prior to birth. This is in accord with previous work on non-mammalian vertebrates suggesting that such cells are morphogenetic intermediates. The results confirm the long-suspected similarity between mammalian primitive erythrocytes and the nucleated erythrocytes of all non-mammalian vertebrates.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970160207
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    Announcement (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 155-155 
    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.970160209
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    Diversity among tubulin subunits: Toward what functional end? (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 159-163 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970160302
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    On metachronism in ciliary systems: A model describing the dependence of the metachronal wave properties on the intrinsic ciliary parameters (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 167-181 
    Details
    ISSN: 0886-1544
    Keywords: metachronal wavelength ; metachronal wave direction ; asymmetry of beating ; ciliary beating ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A mathematical model is proposed to explain the dependence of the direction and the length of the metachronal wave on parameters that characterize the ciliary beat, the dimensions of the cilia, and the geometry of their arrangement on the ciliated surface. The metach/onal wave is decomposed into two mutually perpendicular components, which are chosen in such a way that the direction of one of them is in the direction of the effective stroke. The magnitudes of the two components are determined by using the concept of the time of delay between adjacent cilia. The properties of the metachronal wave are then calculated as a function of the ciliary parameters.The results obtained with the present model predict that the direction of the wave propagation is strongly dependent on the type of metachronism in the direction of the effective stroke and the polarization in time and in space of the ciliary beat. The metachronal wavelength is found to depend on four parameters: the ciliary length, the angle of the arc projected on the cell surface by the ciliary tip during the recovery stroke, the degree of asymmetry of ciliary beat, and the portion of the cycle occupied by the pause. The metachronal wavelength is also found to be only weakly dependent on the ciliary frequency.At this stage there exists relatively little experimental information with which t o characterize fully the metachronal properties of ciliary systems. Even when only partial information exists, the model allows prediction, to within a certain range, of the direction of the wave propagation. It also suggests a possible mechanism for the influence of changes in environmental conditions on wave direction and wavelength. In severalcases in which full information does exist, good agreement between the experimental findings and the predictions of the model is found. According to this model it will be worthwhile to invest more effort in measuring the time and space polarization of ciliary beating and the times of delay between cilia.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970160304
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  • 166
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    Quantitative relationships between single-cell and cell-population model parameters for chemosensory migration responses of alveolar macrophages to C5a (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 279-293 
    Details
    ISSN: 0886-1544
    Keywords: Cell motility ; chemotaxis ; mathematical model ; alveolar macrophages ; C5a ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Phenomenological parameters from a mathematical model of cell motility [1] are used to quantitatively characterize chemosensory migration responses of rat alveolar macrophages migrating to C5a in the linear under-agarose assay, simultaneously at the levels of both single cells and cell populations. This model provides theoretical relationships between single-cell and cell-population motility parameters. Our experiments offer a critical test of these theoretical linking relationships, by comparison of results obtained at the cell population level to results obtained at the single-cell level.Random motility of a cell population is characterized by the random motility coefficient, μ (analogous to a particle diffusion coefficient), whereas single-cell random motility is described by cell speed, s, and persistence time, P (related to the period of time that a cell moves in one direction before changing direction). Population chemotaxis is quantified by the chemotactic sensitivity, χo, which provides a measure of the minimum attractant gradient necessary to elicit a specified chemotactic response. Single-cell chemotaxis is characterized by the chemotactic index, CI, which ranges from 0 for purely random motility to 1 for perfectly directed motility. Measurements of cell number versus migration distance were analyzed in conjunction with the phenomenological model to determine the population parameters while paths of individual cells in the same experiment were analyzed in order to determine the single-cell parameters.The parameter μ shows a biphasic dependence on C5a concentration with a maximum of 1.9 × 10-8 cm2/sec at 10-11 M C5a and relative minima of 0.86 × 10-8 cm2/sec at 10-7 M C5a and 1.1 × 10-8 cm2/sec in the absence of C5a; s and P remain fairly constant with C5a concentration, with s ranging from 2.1 to 2.5 μm/min and P varying from 22 to 32 min. χo is equal to 1.0 × 10-6 cm/receptor for all C5a concentrations tested, corresponding to 60% correct orientation for a difference of 500 bound C5a receptors across a 20 μm cell length. The maximum CI measured was 0.2.Values for the population parameters μ and χo were calculated from single-cell parameter values using the aforementioned theoretical linking relationships. The values of μ and χo calculated from single-cell parameters agreed with values of μ and χo determined independently from population migrations, over the full range of C5a concentrations, confirming the validity of the linking equations. Experimental confirmation of such relationships between single-cell and cell-population parameters has not previously been reported.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970160407
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    Microtubule-associated proteins from antarctic fishes (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 174-186 
    Details
    ISSN: 0886-1544
    Keywords: MAPs ; cold-stable microtubules ; microtubule assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules and presumptive microtubule-associated proteins (MAPs) were isolated from the brain tissues of four Antarctic fishes (Notothenia gibberifrons, N. coriiceps neglecta, Chaenocephalus aceratus, and a Chionodraco sp.) by means of a taxol-dependent, microtubule-affinity procedure (cf. Vallee: Journal of Cell Biology 92:435-442, 1982). MAPs from these fishes were similar to each other in electrophoretic pattern. Prominent in each preparation were proteins in the molecular weight ranges 410,000-430,000, 220,000-280,000, 140,000-155,000, 85,000-95,000, 40,000-45,000, and 32,000-34,000. The surfaces of MAP-rich microtubules were decorated by numerous filamentous projections. Exposure to elevated ionic strength released the MAPs from the microtubules and also removed the filamentous projections. Addition of fish MAPs to subcritical concentrations of fish tubulins at 0-5°C, induced the assembly of microtubules. Both the rate and the extent of this assembly increased with increasing concentrations of the MAPs. Sedimentation revealed that approximately six proteins, with apparent molecular weights between 60,000 and 300,000, became incorporated into the microtubule polymer. Bovine MAPs promoted microtubule formation by fish tubulin at 2-5°C, and proteins corresponding to MAPs 1 and 2 co-sedimented with the polymer. MAPs from C. aceratus also enhanced the polymerization of bovine tubulin at 33°C, but the microtubules depolymerized at 0°C, We conclude that MAPs are part of the microtubules of Antarctic fishes, that these proteins promote microtubule assembly in much the same way as mammalian MAPs, and that they do not possess special capacities to promote microtubule assembly at low temperatures or to prevent cold-induced microtubule depolymerization.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170305
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    Direct observation of microtubule dynamics in Reticulomyxa: Unusually rapid length changes and microtubule sliding (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 214-226 
    Details
    ISSN: 0886-1544
    Keywords: actin ; cytoskeleton ; dynamic instability ; protozoa ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule dynamics has been studied extensively in vitro, but comparatively little information is available on the in vivo behavior of microtubules. Here we report on the assembly, disassembly, and sliding of microtubules in the giant freshwater amoeba, Reticulomyxa. We have found that treating the cell with 0.25% trypsin induces the rapid formation of exceedingly flat areas within the reticulopodial network, allowing for the direct observation of microtubule behavior by DIC optics and computer-enhanced video microscopy. In flattened areas, microtubule sliding occurs at rates of between 1 and 6.5 μm/sec. The average rate of microtubule assembly is 1.6 μm/sec, while microtubule disassembly takes place at about 4 μm/sec and can reach up to 19.5 μm/sec. We also observed many cases where a microtubule forms a hairpin loop and eventually breaks, resulting in bidirectional disassembly from the point of breakage. Our observations demonstrate sliding of cytoplasmic microtubules in vivo. The high rates of microtubule assembly/disassembly in this cell type are difficult to reconcile with conventional views of association and dissociation processes at microtubule ends and suggest unconventional mechanisms for the growth and shrinkage of microtubules.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170308
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    p34cdc2 Kinase is localized to distinct domains within the mitotic apparatus (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 227-235 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; kinetochores ; cell division cycle ; protein phosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Antibodies to both the C-terminal and the N-terminal regions of the 34 kd serinethreonine specific protein kinase, p34cdc2, were used to study the distribution of this protein in dividing cells and isolated chromosomes of the Indian muntjac. p34cdc2 was found to be present throughout the cytoplasm of dividing cells. In addition, a portion of cellular p34cdc2 was localized to the centrosome, kinetochore, and intercellular bridge and along kinetochore-to-pole microtubules during cell division. Tubulin-denuded metaphase kinetochores retained their association with p34cdc2. The detection of p34cdc2 within a variety of domains of the mitotic apparatus, in addition to the previous reported association with the centrosome [Bailly et al., EMBO J. 8:3985-3995, 1989; Raibowol et al., Cell 57:393-401, 1989] suggests that p34cdc2 may play a role in events associated with anaphases A and B as well as with the transition between interphase and mitosis.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170309
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  • 170
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    Effect of filamin and controlled linear shear on the microheterogeneity of F-Actin/Gelsolin gels (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 236-249 
    Details
    ISSN: 0886-1544
    Keywords: bundles ; cytomechanics ; photobleaching ; rheology ; viscoelasticity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously established [Cortese and Frieden, J. Cell Biol. 107:1477-1487, 1988] that actin gels formed under shear are microheterogeneous. In this study, the effect of cross-linking (by chicken gizzard filamin), severing (by plasma gelsolin), and shear on actin microheterogeneity are investigated using fluorescence photobleaching recovery and video microscopy. We find that filamin and shear form microheterogeneous F-actin:gelsolin gels by different mechanisms. Bundling of actin:gelsolin filaments by filamin can be explained by an increase in the apparent length of the filaments due to interfilament binding, resulting in a decrease of the polymer number concentration at which filaments organize into anisotropic phases. Some intrafilament binding of filamin to actin filaments may also be present, and those filaments coated with filamin immobilize more slowly than actin under the same polymerization conditions. The length of F-actin/gelsolin filaments seems to be a major factor in controlling the extent of bundling relative to network formation. In contrast, the effect of shear on the microheterogeneity of actin:gelsolin filaments is consistent with our previous proposal that shear aligns actin filaments, allowing filament-filament interactions and phase formation to occur. Short filaments are unable to organize into branched actin networks, but they can create large aggregates under low shear. Longer actin filaments will exist as networks with variable levels of branching and are less sensitive to shear. The effect of the intensity of a shear field on the spatial distribution of actin may involve a progressively more random orientation of actin molecules and bundles. A regular pattern develops across the sample at low shear rates (0.04-1.39 s-1), and becomes very irregular at higher shear rates (〉 10 s-1). We suggest here that actin-binding proteins and shear can control the transition between isotropic networks and anisotropic phases by their effect on apparent length and local filament concentration, and also that this transition can have substantial effects on the resistance of cells to mechanical stress.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170310
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    Modulation of keratin intermediate filament distribution in vivo by induced changes in cyclic AMP-dependent phosphorylation (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 291-300 
    Details
    ISSN: 0886-1544
    Keywords: PtK1 keratin filaments ; electrophoresis ; autoradiography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Treatment of PtK1 cells with 5 mM acrylamide for 4 hr induces reversible de-phosphorylation of keratin in concert with reversible aggregation of intermediate filaments (Eckert and Yeagle, Cell Motil. Cytoskeleton 11:24-30, 1988). We have examined this phenomenon by 1) in vitro phosphorylation of isolated PtK1 keratin filaments and 2) combined treatments of PtK1 cells with both acrylamide and agents which elevate intracellular cAMP levels. PtK1 keratins were incubated in gamma-32P-ATP in the presence or absence of cAMP-dependent kinase (A-kinase) and cAMP. Levels of phosphorylation were analyzed by electrophoresis and autoradiography. Phosphorylation of keratin polypeptides (56 kD, 53 kD, 45 kD, 40 kD) occurred without added kinase, suggesting the presence of an endogenous kinase which remains with intermediate filaments in residues of Triton X-100 extracted cells. Phosphorylation levels were increased by A-kinase but not by cAMP alone, indicating the presence of cAMP-dependent phosphorylation sites in addition to sites phosphorylated by the endogenous kinase. To study the possible role of cAMP-dependent phosphorylation in acrylamide-induced aggregation of keratin filaments, we treated cells with acrylamide in the presence of 8-bromo-cAMP (brcAMP), pertussis toxin (PT), isobutylmethylxanthine (IBMX), or forskolin, which increase intracellular cAMP levels. The distribution and phosphorylation levels of keratin filaments, as well as intracellular cAMP levels, were determined for each of these treatments. In addition to aggregation and dephosphorylation of keratin filaments reported previously, treatment of cells with acrylamide alone also results in reduced levels of intracellular cAMP. 8-bromo-cAMP, IBMX, and forskolin prevent acrylamide-induced aggregation of keratin filaments and result in both normal levels of keratin phosphorylation and normal intracellular cAMP levels. PT was apparently ineffective. These observations suggest that 1) PtK1 keratins are phosphorylated by cAMP-dependent kinase and an endogenous, cAMP-independent kinase and 2) alteration of levels of cAMP-dependent phosphorylation may be involved in aggregation of keratin filaments in response to acrylamide.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970170404
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040101
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    Diary (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. i 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040102
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  • 174
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    Mixture analysis using factor analysis. II: Self-modeling curve resolution (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 1-13 
    Details
    ISSN: 0886-9383
    Keywords: Factor analysis ; Self-modeling curve resolution ; Spectra isolation ; Target transformation factor analysis ; Iterative target transformation factor analysis ; Evolving factor analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One of the major applications of factor analysis in the chemical literature, self-modeling curve resolution (SMCR), is covered in this review, including a historical account of the methods derived from Lawton and Sylvestre's original method. Papers treating the theory or applications of SMCR are included. Qualitative and quantitative applications are described where appropriate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040103
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    The effect of mislabeled samples on the performance of the linear learning machine (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 47-50 
    Details
    ISSN: 0886-9383
    Keywords: Classification ; Pattern recognition ; Preprocessing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Over the past 15 years the linear learning machine has been applied to a large number of chemical problems. The learning machine approach is conceptually simple and does not require knowledge about the statistical distribution of the data. However, there are problems associated with this approach. One problem which has not been investigated is the influence of mislabeled samples on the positioning of the hyperplane in feature space. If a few samples in a data set are incorrectly tagged prior to training (i.e. the samples are labeled as members of class 2 even though they are actually members of class 1), it is still possible using the linear learning machine to achieve a classification success rate of 100% for the training set. However, unfavorable results will be obtained for the prediction set. The magnitude of this effect and its potential implications regarding the proper use of the linear learning machine are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040106
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    Enhancing the deconvolution of noisy chromatographic data by Jansson's method (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 51-59 
    Details
    ISSN: 0886-9383
    Keywords: Deconvolution ; Jansson's method ; Peak restoration ; Iterative deconvolution ; Peak resolution ; Non-linear deconvolution ; Super-resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In previous papers Jansson's method was found to be successful at deconvolving severely overlapped gas chromatographic peaks. In the most recent paper the method was evaluated with respect to quantitative accuracy, peak area and retention time repeatability. The problems associated with deconvolving noisy data and some alternatives which can improve the ability of Jansson's method to deconvolve noisy data are discussed. These alternatives include presmoothing the data with a nine-point, third-order polynomial filter and data reblurring. This paper will test these methods on peaks with various degrees of resolution and signal-to-noise ratios.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040107
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    A new approach to confirmation by infrared spectrometry (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 61-77 
    Details
    ISSN: 0886-9383
    Keywords: Infrared ; Spectroscopy ; Spectrometry ; Retrieval ; Confirmation ; Chemometrics ; Adequate peaks ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the series of analytical techniques for identification of chemical substances, infrared spectrometry presents by far the highest information content. However, the information is most complicated too. It concerns a multitude of band positions, band intensities and band shapes, which, moreover, can be disturbed by matrix and other effects. The high redundancy, however, allows conclusions to be made by a qualitative, subjective procedure.IR is often used to prove the equality between a sample and a reference material, e.g. in quality control of a production process. In forensic control, the question to be answered is mostly not to prove equality, but whether or not the presence of a compound in a sample, e.g. a drug, can be proved. Moreover, testing has to be performed according to objective rules.To fulfil these requirements, a new retrieval algorithm, the ‘Adequate Peaks Search’, is presented. It concerns representing the reference spectra by sets of adequate peak positions and the sample spectrum by a set of all peak positions, whereafter the cross-sections of the sample set and the reference sets are determined. The concept ‘adequate peak’ is defined and criteria have been formulated to evaluate the results into a positive (presence of the analyte is proved) or negative (presence is not proved) conclusion.The detection limit when the Adequate Peaks Search (APS) method was applied was four to seven times lower than that attained by a number of experts.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040108
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    Residual bilinearization. Part 1: Theory and algorithms (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 79-90 
    Details
    ISSN: 0886-9383
    Keywords: PLS ; Three-way matrices ; Calibration ; Residual bilinearization ; Background correction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When using hyphenated methods in analytical chemistry, the data obtained for each sample are given as a matrix. When a regression equation is set up between an unknown sample (a matrix) and a calibration set (a stack of matrices), the residual is a matrix R.The regression equation is usually solved by minimizing the sum of squares of R. If the sample contains some constituent not calibrated for, this approach is not valid. In this paper an algorithm is presented which partitions R into one matrix of low rank corresponding to the unknown constituents, and one random noise matrix to which the least squares restrictions are applied. Properties and possible applications of the algorithm are also discussed.In Part 2 of this work an example from HPLC with diode array detection is presented and the results are compared with generalized rank annihilation factor analysis (GRAFA).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040109
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  • 179
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    The problem of adequate sample size in pattern recognition studies: The multivariate normal case (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 91-96 
    Details
    ISSN: 0886-9383
    Keywords: Sample size ; Monte Carlo ; Multivariate, normal ; Q-Q plots ; Classification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Because many pattern recognition techniques are predicated on the assumption of mutivariate normal data, Monte Carlo simulation studies were performed to determine the number of samples that are necessary to describe a multivariate normal population adequately. From these studies we have learned that hundreds of samples are required. These results suggest that parametric procedures should only be used to analyze very large data sets.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040110
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    Comments on the NIPALS algorithm (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 97-100 
    Details
    ISSN: 0886-9383
    Keywords: Matrix decomposition ; NIPALS ; Principal component ; SIMCA ; PLS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Non-linear Iterative Partial Least Squares (NIPALS) algorithm is used in principal component analysis to decompose a data matrix into score vectors and eigenvectors (loading vectors) plus a residual matrix. NIPALS starts with some guessed starting vector. The principal components obtained by NIPALS depends on the starting vector; the first principal component could not always be computed. Wold has suggested a starting vector for NIPALS, but we have found that even if this starting vector is used, the first principal component cannot be obtained in all cases. The reason why such a situation occurs is explained by the power method. A simple modification of the original NIPALS procedure to avoid getting smaller eigenvalues is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040111
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    From CA to CAS online, Hedda Schulz, VCH Publishers, Weinheim, Federal Republic of Germany, 1988. No. of pages: viii + 227. Price $39.95. ISBN 0-89573-815-5 (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 101-101 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040112
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    Diary (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. i 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040202
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  • 183
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    Recursive parameter estimation (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 103-121 
    Details
    ISSN: 0886-9383
    Keywords: Kalman filter ; Recursive digital filter ; Square-root filter ; Information filter ; Parameter estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of recursive filtering techniques for parameter estimation in a variety of areas is reviewed. In particular, the Kalman filter algorithm is described, along with several variations, including square-root, UDUT and information filters. The solution to parameter estimation problems is discussed for both linear and non-linear models. Applications described include calibration, curve resolution in spectroscopy, chromatography, electrochemistry, kinetic analysis and process monitoring.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040203
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    Announcement (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 267-268 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040307
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    Algorithms for chemists, Jure Zupan, John Wiley and Sons, Ltd., Chichester, 1989. Price: £39.50, US$75.90, ISBN 0 47192173 4 (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 269-269 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040308
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040401
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    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180040501
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  • 188
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    Formation of miniasters in the cytoplasm of hexyleneglycol-treated sea urchin eggs (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 23-33 
    Details
    ISSN: 0886-1544
    Keywords: centrosome ; cytaster ; MTOG ; pericentriolar material ; 51 kD protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Miniasters formed in mitotic sea urchin egg after treatment with 5% hexylene-glycol were investigated with the combined techniques of indirect immunofluo-rescence using anti-tubulin and anti-51 kD protein antibodies and electron microscopy.The formation of miniasters was dependent on the mitotic cycle. In the cytoplasm of eggs treated with hexyleneglycol at early prometaphase, a small number of microtubule fragments was observed, whereas in those treated at pro-metaphase, many miniasters and microtubule fragments were seen. When treated at metaphase, we found a great number of miniasters: 250-350 in one egg. In contrast, no miniasters were seen in eggs treated at anaphase, although many long microtubules that spread throughout the cytoplasm were observed. In the eggs treated at telophase, we scarcely noticed microtubule structures in the cytoplasm. In the center of miniasters, granules were found, showing the same size and electron density as those of the microtubule-organizing granules (MTOGs). Furthermore, the 51 kD protein, a component of the centrosome and mitotic spindle, was observed to be localized in the region of miniasters.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150105
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    Recent progress on structural interactions of the endoplasmic reticulum (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 71-75 
    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.970150203
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  • 190
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    Role of microtubules in the organisation of the Golgi apparatus (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 67-70 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150202
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  • 191
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    In vitro induction of crawling in the amoeboid sperm of the nematode parasite, Ascaris suum (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 99-110 
    Details
    ISSN: 0886-1544
    Keywords: ascaris ; nematode ; nematoda ; sperm ; amoeboid motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a highly synchronous process, the immotile spermatids of Ascaris suum extend pseudopods and become rapidly crawling sperm when treated with an extract from the glandular vas deferens of the male under strict anaerobic conditions. Within 9-12. min, a pseudopod develops, elongates rapidly, and exhibits a continuous flow of membrane specializations, the villipodia, from tip toward base. When attached to acid-washed glass, the pseudopod pulls the cell body along at speeds exceeding 70 μm/min. The pseudopod length remains constant while retrograde flow of villipodia proceeds at the same rate as the sperm's forward movement. Cohorts of about 15 villipodia form at the leading edge, move reaward together, and disappear at the junction of pseudopod and cell body. These are the termination of branched, refringent fibers, which extend the length of the pseudopod. The latter are the fiber complexes that form its cytoskeleton (Sepsenwol et al.: Journal of Cell Biology 108:55-66, 1989). Locomoting cells sometimes change direction when another crawls by and follow each other. When cells are exposed to air, forward movement ceases in a predictable pattern: the forward extension of the leading edge ceases, the pseudopod shortens from the base, and the cell body continues to be pulled forward. These data contribute to a model for Ascaris sperm amoeboid motility in which independent processes of continuous extension at the leading edge and continuous shortening at the base of the pseudopod act to propel the cell forward.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150206
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  • 192
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    Partial characterization of a carotenoid droplet ATPase and its possible significance in carotenoid droplet dispersion in goldfish xanthophores (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 147-155 
    Details
    ISSN: 0886-1544
    Keywords: organelle translocation ; translocator ; actin-dependent ATPase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dispersion of carotenoid droplets in permeabilized goldfish xanthophores is dependent on ATP, F-actin, and cytosol. We report here that the motor (ATPase, translocator) resides with the permeabilized cell remnants and not in the cytosol. We also report that the carotenoid droplets have an ATPase that is not conventional myosin, dynein, or an ion pump. Its activity appears to correlate with the actin content of the carotenoid droplet preparation. A carotenoid droplet protein of Mr 72,000 (p72) is shown to be labeled by irradiation with 8-azido-ATP with concomitant loss of ATPase activity of the carotenoid droplets. We propose that this protein may be the ATPase responsible for carotenoid droplet dispersion.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150303
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    Actin-dependent carotenoid droplet dispersion in permeabilized cultured goldfish xanthophores (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 139-146 
    Details
    ISSN: 0886-1544
    Keywords: organelle translocation ; cytosolic factor ; secretion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Organelle translocations are essential cellular processes. Although much progress has been made with regards to microtubule-dependent organelle translocations, little is known about actin-dependent organelle translocation(s) except cytoplasmic streaming in Nitella. On the other hand, there is indirect evidence that actindependent organelle translocation may be involved in secretion. We now present evidence that the dispersion of the pigment organelles carotenoid droplets in goldfish xanthophores is apparently actin dependent and that this process may be related to secretory processes. We show that, in digitonin-permeabilized goldfish xanthophores, the pigment organelles can be induced to disperse by a combination of cAMP, ATP, and xanthophore cytosol. This induced dispersion is inhibited by DNase I, phalloidin, or anti-actin, but not by anti-tubulin or anti-intermediate filament proteins, suggesting a dependence on F-actin. Since the dispersion of carotenoid droplets and secretion both involve outward translocation of organelles, we tested the possibility that cytosols of secretory tissues have similar activity. Such activity was indeed found in different tissues, apparently in parallel with the secretory activity of the tissues, suggesting that pigment dispersion in xanthophores and some secretory processes may share a common component.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150302
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  • 194
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    Structural plugs at microtubule ends may regulate polymer dynamics in vitro (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 15 (1990), S. 156-161 
    Details
    ISSN: 0886-1544
    Keywords: microtubule structure ; microtubule assembly ; electron microscopy of microtubules ; polymer stabilization ; microtubule-capping structures ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules contain in their lumens distinct structures (plugs) that influence their dynamic behavior in vitro. As observed by electron microscopy, plugs are stainoccluding structures 10-30 nm in length that occur along the lengths and at the ends of microtubules. Plugs occur at a frequency of 20-40% at the ends of microtubules assembled from cycled microtubule protein containing MAPs. While the composition of plugs is not known, preliminary evidence suggests that they are accretions of tubulin, that they are labile, and that they are more common in preparations containing MAPs. When polymers are induced to depolymerize by endwise subuit dissociation, the frequency of plugged microtubule ends increases transiently, suggesting that plugs temporarily stabilize microtubules. The functional significance of plugs may be that they prevent the sudden complete loss of microtubules through catastrophic disassembly. It is possible that plugs, by slowing the rate of disassembly, enable a polymer to add GTP-tubulin subunits, thereby forming a stabilizing GTP-cap. These observations suggest that plugs may stabilize polymers and account for the frequent transitions from shortening to growing phases that characterize dynamic instability.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970150304
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  • 195
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    Neurite elongation is blocked if microtubule polymerization is inhibited in PC12 cells (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 95-105 
    Details
    ISSN: 0886-1544
    Keywords: colchicine-tubulin ; neurite growth ; process extension ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have injected process-bearing PC12 cells with colchicine-tubulin mixed with either fluorescein-dextran or a rhodamine-labelled tubulin analogue to determine the role of microtubule polymerization in neurite elongation. Colchicine-tubulin is a specific, substoichiometric poison of microtubule assembly. We have shown that colchicine-tubulin does not cause existing PC12 microtubules to disassemble, and yet can inhibit the assembly of rhodamine-tubulin injected along with it. In population s'udies of neurite outgrowth in injected and uninjected cells, we find that colchicine-tubulin substantially inhibits neurite extension from injected cells over a wide variety of concentrations. In acute time-course studies of injected cells, we find that colchicine-tubulin does not block neurite outgrowth until the injectate reaches the neurite tip. Thereafter, however, it blocks process elongation completely. Thus we can conclude that microtubule polymerization in the region of the growth cone is an important element in neurite elongation. While polymerization at the cell body may be important in supplying subunits to the distal neurite, it does not play a direct role in process extension.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970170205
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  • 196
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    Propranolol, a β-adrenergic receptor blocker, affects microfilament organization, but not microtubules, during the first division in sea urchin eggs (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 182-189 
    Details
    ISSN: 0886-1544
    Keywords: cell division ; receptors ; neurotransmitter ; micronlaments ; mitosis ; cytokinesis ; sea urchin eggs ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Propranolol, a β-adrenergic receptor blocker, blocks the formation of the cleavage furrow, while karyokinesis is unaffected during first division in the sea urchins Paracentrotus lividus or Lytcchinus pictus. This effect is reversed by adrenalin, indicating that it is mediated by an adrenergic mechanism. The staining of F-actin microfilaments by rhodamine phalloidin in eggs in which the cleavage is blocked by the drug has revealed that propranolol affects both the distribution and the organization of actin microfilaments. A low-voltage scanning electron microscopy (LVSEM) study of microvilli in these eggs shows an extensive rearrangement of the egg surface. Anti-tubulin immunofluorescence microscopy of eggs treated with propranolol shows that they form normal mitotic asters. This indicates that while cleavage is affected, mitotic spindle formation is not. These results suggest that neurotransmitter monoamines known to be present in the sea urchin egg might be involved in the reorganization of the actin cytoskeleton underlying the formation of the cleavage furrow.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970160305
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  • 197
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    Behavior of C-shaped microtubule endings in the cell (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 59-67 
    Details
    ISSN: 0886-1544
    Keywords: Polytoma papillatum ; Megaselia scalaris ; protofilament ; mitosis ; meiosis ; spindle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The association of incomplete microtubule assemblies with either another incom-plete structure or complete microtubules was studied in two organisms, the phytoflag-ellate Polytoma papillatum and the phorid fly Megaselia scalaris, using transmission electron microscopy. In the alga, hook-shaped appendages on cytoplasmic and spindle microtubules were detected. These resulted from the lateral association of a curved ribbon of protofilaments with the surface of a complete microtubular wall. In the fly, an S-shaped protofilament sheet was found embedded in the kinetochore plate of a prometaphase I spematocyte. Tracing of the S-shaped element towards the spindle pole revealed that it was formed by the lateral junction of two curved protofilament sheets. In all cases, the C-shaped protofilament sheets represented the endings of complete micro-tubules. Incomplete microtubules are generally considered as representing intermediates of microtubule assembly and disassembly. Since high molecular weight proteins are believed to be responsible for maintaining microtubule-microtubule spacing, it is hypo-thesized that the endings of growing and shrinking microtubules are sparsely studded with these proteins; their depletion allows lateral microtubule contacts. In addition, the microtubule-microtubule contacts may be rendered possible by the flexibility of the slender elongated microtubule-associated molecules. Relatively long C-shaped proto-filament appendages (0.6-1.4 μm) were detected in this study. Therefore, it is plausible to assume that the protofilament sheets are stabilized by contact with one another or with an intact tubule wall.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970170108
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  • 198
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    Electronic Resource
    Masthead (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990) 
    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.970160101
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  • 199
    Electronic Resource
    Electronic Resource
    Cytoskeletal dynamics in rabbit synovial fibroblasts: II. Reformation of stress fibers in cells rounded by treatment with collagenase-lnducing agents (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 121-132 
    Details
    ISSN: 0886-1544
    Keywords: microfilaments ; cytochalasin ; cell shape ; integrins ; intermediate filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Modulation of the synthesis and secretion of extracellular matrix proteins and matrix-degrading metalloproteases by rabbit synovial fibroblasts in an important model system for studying the control of tissue-specific gene expression. Induction of collagenase expression is correlated with changes in cell shape and actin filament distribution, but the role of the cellular cytoskeleton in the sustained synthesis and secretion of metalloproteases has not been closely examined. When cells were allowed to respread after rounding by trypsin or cytochalasin, two known metalloprotease inducers, reformation of stress fibers was observed within 2 h in the presence of serum. In the absence of serum, trypsin-treated cells did not respread substantially, even after 24 h in culture. In contrast, cytochalasin-treated cells recovered almost as rapidly in the absence as in the presence of serum, showing reformation of well-formed microfilament bundles within 30 min of drug removal, especially at the spreading cell edges. High resolution electron-microscopic views of detergent-extracted cytoskeletons confirmed the rapid rebundling of peripheral microfilaments. Acrylamide-treated cells fell between these two extremes, spreading slowly in the absence of serum, but almost as rapidly as cytochalasin-treated cells in its presence. Reestablishment of normal intermediate filament distribution generally lagged slightly behind actin for all treatments, and intermediate filaments always appeared to spread back into the cellular cytoplasm within the confines of the reforming peripheral microfilament bundles. No obvious interaction between these two cytoskeletal elements was observed after any treatment, and no specific role for intermediate filaments in modulating gene expression in these cells is suggested by these results. The serum dependence displayed after trypsin or acrylamide treatment may be due to the disturbances in fibronectin synthesis observed in these cells and is consistent with evidence that both induction and sustained expression of matrix-degrading metalloprotease may involve signals transduced through plasma membrane matrix receptors (integrins).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970160206
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  • 200
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    Electronic Resource
    Light chains of sea urchin kinesin identified by immunoadsorption (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 16 (1990), S. 204-213 
    Details
    ISSN: 0886-1544
    Keywords: kinesin ; molecular structure ; immunoaffinity purification ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous studies with monoclonal antibodies indicate that sea urchin kinesin contains two heavy chains arranged in parallel such that their N-terminal ends fold into globular mechanochemical heads attached to a thin stalk ending in a bipartitetail [Scholey et al. 1989]. In the present, complementary study, we have used the monoclonal antikinesin. SUK4, to probe the quaternary structure of sea urchin (Strongylocentrotus purpuratus) kinesin. Kinesin prepared from sea urchin cyto-sol sedimented at 9.6 S on sucrose density gradients and consisted of 130-kd heavy chains plus an 84-kd/78 kd doublet (1 mol heavy chain: 1 mol doublet determined by gel densitomctry). Low levels of 110-kd and 90-kd polypeptides were sometimes present as well. The 84-kd/78 kd polypeptides are thought to be light chains because they were precipitated from the kinesin preparation at a stoichiometry of one mol doublet per 1 mol heavy chain using SUK4-Sepharose immunoaffinity resins. The 110-kd and 90-kd peptides, by contrast, were removed using this immunoadsorption method. SUK4-Sepharose immunoaffinity chromatography was also used to purify the 130-kd heavy chain and 84-kd/78-kd doublet (1 mol heavy chain: 1 mol doublet) directly from sea urchin egg cytosolic extracts, and from a MAP (microtubule-associated protein) fraction eluted by ATP from microtubules prepared in the presence of AMPPNP but not from microtubules prepared in ATP. The finding that sea urchin kinesin contains equi-molar quantities of heavy und light chains, together with the aforementioned data on kinesin morphology, suggests that native sea urchin kinesin is a tetramer assembled from two light chains and two heavy chains.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970160307
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