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  • 1995-1999
  • 1990-1994  (2,903)
  • 1890-1899  (18)
  • 1992  (2,903)
  • 1892  (18)
  • Life and Medical Sciences  (2,233)
  • Chemical Engineering  (688)
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Years
  • 1995-1999
  • 1990-1994  (2,903)
  • 1890-1899  (18)
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    The development of Caretta caretta, at 25-34°C, in artificial nests (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 251-263 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron microscopy has been used to enhance the description of a single species, Caretta caretta (the loggerhead turtle), staged according to Miller's system for the development of marine turtles. Incubation over a temperature range of 25°-34°C confirms previous observations that, under artificial conditions and at a constant incubation temperature, normal development is confined to a limited temperature range. Premature pipping is a feature of incubation at the lower end of this range; abnormal development, generated during the first third of the incubation period, occurs just above the normal range. Details of the external morphology of embryos from Miller stage 14 through to 25 are given together with an account of the developmental abnormalities produced at a high temperature of incubation. The data obtained confirm that Miller's scheme is generally applicable to C. caretta, provided that due regard is paid to the incubation temperature. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052130209
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  • 102
    Electronic Resource
    Electronic Resource
    Jaw-muscle activity in ferrets, Mustela putorius furo (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 275-286 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographical (EMG) activity was recorded bilaterally from the masseter and temporalis muscles of alert ferrets (Mustela putorius furo) during mastication and crushing. Electromyographic activity was also recorded during biting while a bite-force transducer placed between the carnassial teeth registered forces ranging from 1.5 to 48.8 N. Linear regression analysis demonstrates that temporalis and masseter EMG activity are linearly related to bite force. Electromyographic activity from the balancing-side muscles is nearly equal to EMG activity of the working-side muscles during bone crushing with the carnassial teeth. It is hypothesized that a high percentage of balancing-side muscle activity in ferrets can be recruited during carnassial biting because the postglenoid process prevents ventral displacement of the working-side mandibular condyle. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052130211
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  • 103
    Electronic Resource
    Electronic Resource
    Ultrastructural qualitative and quantitative data on the sporogenesis of the protozoan Abelspora portucalensis (microspora, abelsporidae): A different approach to the study of microsporidia (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 295-303 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sporogenesis of the microsporidium Abelspora portucalensis was studied with electron microscopy. In qualitative terms, new aspects of the cytoplasmic ultrastructure of the schizont, sporont, and sporoblast are described: the presence of microtubules, of aggregates of small opaque vesicles, and of dispersed larger vesicles with clear matrix. The hypothesis that the opaque vesicles may represent the Golgi apparatus and the clear vesicles may correspond to the smooth endoplasmic reticulum is discussed. The use of standard stereological and statistical techniques gives us a new perspective on the development of this microsporidium. The most relevant quantitative data display that the amount of rough endoplasmic reticulum (either in relative or absolute terms) presents significant differences among the three stages, with the sporont showing the highest values; that the absolute (but not the relative) volume of the large vesicles significantly changes during sporogenesis with the highest values presented by the sporont; that the surface-to-volume ratio of the schizont and sporont cells is similar and significantly greater than that of the sporoblast cell; that the surface density of the nucleus in relation to soma remains constant in the three stages (on the contrary, the surface-to-volume ratio of the nucleus increases and its volumetric density diminishes); and finally, that the nucleolus decreases its relative and absolute volumes. The functional significance of these results is analyzed and the application of similar methodology in quantifying the effects of drugs upon microsporidia is suggested. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052130303
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  • 104
    Electronic Resource
    Electronic Resource
    Influence of web-monitoring tactics on the density of mitochondria in leg muscles of the spider family uloboridae (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 341-347 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From electron micrographs we determined the ratio of mitochondrial to myofibril cross sectional area in cells of the first leg anterior depressor muscles of adult females of four spider species, each from a different genus. Species with more active web-monitoring tactics and greater tracheal supplies to their first legs have muscle cells that are better supplied with mitochondria than those with less active tactics and less well-developed tracheal systems. These results demonstrate that, even in homologous tissues of closely related species, mitochondrial supply can change to accommodate changes in metabolic activity. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052130307
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  • 105
    Electronic Resource
    Electronic Resource
    Three nephromixial patterns in polychaete species currently assigned to the genus Pista (Annelida, Terebellidae) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 365-393 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A comparative morphological study of nephromixial systems in three Californian terebellid polchaetes currently assigned to the genus Pista shows that P. fimbriata has all attributes of the generic type, but that P. pacifica and P. elongata differ markedly. The features of typical Pista include (among others): two pairs of usually unequal branchiae, long-handled anterior uncini (hooks) of crested avicular (bird-head-like) from, muddy, unornamented tubes, one pair of anterior excretory nephromixia (ENMX), and two pairs of separate thoracic reproductive nephromixia (RNMX) with genital papillae on segments VI and VII. A review indicates that P. fimbriata shares these typical features with practically all adequately described Pista species. However, P. pacifica and P. elongata possess three pairs of branchiae, long-handled uncini of distinctive crochet-like form, and membranous tubes with apertural hoods. Both have two pairs of ENMX, the first supplied by one pair of ciliated renal funnels, the second by two pairs of such funnels. But they differ in their RNMX: P. pacifica has three pairs of complex RNMX, those on each side united by a common duct. P. elongata has 11-13 pairs of simple RNMX united by common ducts. Although these species do not fit into Pista, no genus has been found to accommodate them. Generic placement is complicated by the fact that no instances of intra-generic nephromixial variation have been reported in the Terebellidae, although inter-generic variation is well known. If they are congeneric, this would be the first example of intrageneric RNMX variation in Terebellidae. But if assigned to separate genera or subgenera on the basis of their RNMX, their similarity of anterior uncini might be attributable to parallel or convergent adaptation to life in comparable tubes. More evidence, including molecular analysis, is needed for phylogenetic studies of Terebellidae. © 1992 Wiley-Liss, Inc.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052130309
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  • 106
    Electronic Resource
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    The ear in subterranean insectivora and rodentia in comparison with ground-dwelling representatives. I. Sound conducting system of the middle ear (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 49-61 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Compared to acoustically unspecialized mammals (soricids and murids), the middle ear of subterranean insectivores and rodents (twelve species of six families examined) was clearly distinguished and characterized by many common features: rather round and relatively larger eardrum without a pars flaccida; reduced gonial; loose or no connection between the malleus and the tympanic bone; reduced and straightened transversal part of the malleus; enlarged incus; increased and rather flat incudo-mallear joint; rather parallel position of the mallear manubrium and incudal crus longum in some species (and their fusion in abthyergids); reduced or even missing middle ear muscles. Convergent occurrence of these structural features in taxa of different origin and their generally derived character suggest that they cannot be categorized as degenerative. The form of the stapes can be considered as a non-adaptive trait; it was taxon specific yet remarkably polymorphous in some species and exhibited no convergent features among subterranean mammals. Structural retrogression resulting in a columella-like stapes was observed in some species lacking the stapedial artery. The stapedial base was relatively larger than in unspecialized mammals. The subterranean mammals did not exhibit conspicuously enlarged eardrums as would be required for sensitive tuning to low frequencies. It is, however, argued that while selective pressures in the subterranean ecotope promoted hearing of low frequencies, hearing sensitivity did not have to be enhanced. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140104
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  • 107
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992) 
    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.1052140201
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  • 108
    Electronic Resource
    Electronic Resource
    Differences in morphological features of the sacculus of the inner ear of two hakes (Merluccius capensis and M. paradoxus, gadiformes) inhabits from different depth of sea (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 97-107 
    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 of the sensory epithelia of the sacculus in two species of hake, Merluccius capensis and M. paradoxus, was analyzed by scanning electron microscopy (SEM). The sensory epithelia have two morphological features that are very different from other gadiform species. These include the presence of two large areas which are only linked by a narrow neck, and the larger proportion of hair cells oriented in the rostrocaudal axis than in other species. The deeper-dwelling species, M. paradoxus, has a larger proportion of hair cell with short ciliary bundles than does the shallower-dwelling species, M. capensis. These morphological specializations could improve the acoustic diserimination and localization capabilities of these species, possibly related to an increase in sensitivity to higher frequency sounds in the deeper-dwelling species. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140107
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  • 109
    Electronic Resource
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    A study of ovarian foilicular kinetics, oviduct, fat body, and liver mass cycles in laboratory-maintained Rana cyanophlyctis in comparison with wild-caught frogs (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 123-129 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ovarian follicular dynamics and fluctuations in fat body, oviducal, and liver masses were studied in captive Rana cyanophlyctis in comparison with wild-caught frogs, sampled at monthly intervals over a period of 12 months. In both the captive and wil-dcaught frogs first growth phase (FGP) and second growth phase (SGP) or vitellogenic oocytes were produced throughout the period examined; however, changes in ovarian and oviducal weights were less marked in the former group.In the captive frogs SGP oocyte production was reduced by 50%, and, maximum ovarian weight and SGP oocyte number were attained 2-3 months earlier than in wild-caught controls. The FGP oocyte pool in laboratory-maintained frogs, however was comparable with that of the corresponding wild-caught frogs. Captivity caused a threefold increase in atresia and reduced the number of oocytes reaching SGP. The depletion of fat stores in fat bodies during the later phases of captivity suggests that the deposition of lipids into oocytes (for SGP) was given priority over storage in the fat bodies.The low oviducal weights of captive frogs was correlated with a reduced number of SGP oocytes, which are the source of estrogen. On the other hand, liver weight remained high, indicating adequate hepatic vitellogenin synthesis. Possible reduction in its output was not detected, possibly due to the reduced number of follicles reaching SGP. The findings indicate that stress of captivity decreases gonadotrophins and estrogen levels. Oviducal growth is reduced in captive frogs. It is hypothesized that in the frog oviducts respond to estrogen in a threshold-dependent manner, whereas the liver responds to it in relation to the length of exposure. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140202
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  • 110
    Electronic Resource
    Electronic Resource
    Cytoplasmic droplets of painted turtle spermatozoa (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 153-158 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Epididymal sperm from the painted turtle (Chrysemys picta) possess a cytoplasmic droplet which is located eccentrically on the sperm midpiece. The droplet contains a large quantity of lipid droplets in addition to hollow vesicles and degenerate mitochondrial fragments. Lipid droplets are closely associated with mitochondrial membranes and may function in the formation or degradation of mitochondria. Cytoplasmic droplets become detached from the sperm midpiece in a coordinated manner shortly before the commencement of fall mating and are not observed on sperm recovered from the oviduct of females. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140205
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  • 111
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992) 
    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.1052140301
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  • 112
    Electronic Resource
    Electronic Resource
    Specialized veins in the submucosa of the equine lleocecal junction (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 261-267 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spirally arranged bundles of sub-endothelial smooth muscle enfold the small to medium-sized submucosal veins in the equine ileocecal junction. The muscle bundles, accompanied by the endothelial lining, bulge into the lumen of the vessels, partly occluding the latter. Transmission electron microscopy of the muscle cells reveals features consistent with vascular smooth muscle ultrastructure. It is proposed that the throttling effect of the muscle bundles causes engorgement of the submucosal venous plexus, which then assists in the closing of the ileocecal orifice. © 1992 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140303
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  • 113
    Electronic Resource
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    Fine structure of the skin of the amphibious fishes, Boleophthalmus pectinirostris and Periophthalmus cantonensis, with special reference to the location of blood vessels (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 287-297 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The skin of the amphibious fishes, Periophthalmus cantonensis and Boleophthalmus pectinirostris, was investigated by transmission electron microscopy (TEM). In both species the epidermis consists of superficial nonvacuolated epithelial cells, swollen epithelial cells with membrane limited cytoplasmic vacuoles, and basal epithelial cells in a single layer. Unicellular mucous glands, but no chloride cells are found in the epidermis of B. pectinirostris; in contrast there are chloride cells and no unicellular mucous cells in P. cantonensis. Intraepidermal blood vessels are a notable feature in the epidermis of P. cantonensis. Capillaries are distributed near the epidermal surface, offering an air-blood barrier of sufficient thinness (2-4 μm) for cutaneous respiration. The large blood vessels (arterioles and venules) are seen in the middle stratum of the epidermis and seem to be able to regulate blood flow in the skin. In B. pectinirostris, the dermal capillaries lie immediately below the superficial epithelial cells at the apex of a dermal bulge where the air-blood barrier is almost as thin as that of P. cantonensis despite locally different histology. In the spacious dermal bulges, the dermal tissue such as blood vessels, pigment cells, fibroblasts, and collagen fibers are scattered. Melanophores and two other types of chromatophores occur in the part adjacent to the blood vessel wall. The organization of the epidermis and blood vessels of the skin is discussed with regard to terrestrial life in these amphibious fishes. © 1992 Wiley-Liss, Inc.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140305
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  • 114
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    Sutural complexity in artificially deformed human (Homo sapiens) crania (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 321-332 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pattern of complexity of cranial sutures is highly variable both among and within species. Intentional cranial vault deformation in human populations provides a controlled natural experiment by which we were able to quantify aspects of sutural complexity and examine the relationship between sutural patterns and mechanical loading. Measures of sutural complexity (interdigitation, number, and size of sutural bones) were quantified from digitized tracings of 13 sutures and compared among three groups of crania (n = 70) from pre-European contact Peru. These groups represent sample populations deformed in (1) anteroposterior (AP) and (2) circumferential (C) directions and (3) an undeformed population. Intergroup comparisons show few differences in degree or asymmetry of sutural interdigitation. In the few comparisons which show differences, the C group is always more interdigitated than the other two while the AP group has more sutural bones. The sutures surrounding the temporal bone (sphenotemporal, occipitotemporal, and temporoparietal) most frequently show significant differences among groups. These differences are related to the more extreme binding of C type deformation and are consistent with hypothesized increases in tension at coronally oriented sutures in this group. The larger number of sutural bones in the AP group is consistent with the general broadening of the cranium in this group and with experimental evidence indicating the development of ossicles in areas of tension. We suggest that so few changes in sutural complexity occurred either because the magnitude of the growth vectors, unlike their direction, is not substantially altered or because mechanisms other than sutural growth modification are responsible for producing the altered vault shapes. In addition, the presence of fontanelles in the infant skulls during binding and the static nature of the binding may have contributed to the similarity in complexity among groups. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052140307
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  • 115
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    The interrenal gland of Triturus cristatus after insulin administration during the annual cycle (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 87-93 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The administration of insulin to Triturus cristatus confirms its action in depletion of the adrenalin (A) granules of the adrenal chromaffin cells and the subsequent activation of phenylethanolamine-N-methyltransferase (PNMT). Treatment was carried out in March, when noradrenalin (NA) and A granules are present in almost equal quantities in the chromaffin cells, and in June, when NA granules largely prevail. After insulin administration, adrenalin content of the specimens treated in March decreases from 2.44 granules/μm2 to 0.28 granules/μm2; on the other hand, adrenalin content of the specimens treated in June increases from 0.19 granules/μm2 to 0.31 granules/μm2. These results suggest that in T. cristatus insulin acts both as an adrenalin-releasing agent and as a stimulator of PNMT activity.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052110110
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  • 116
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    The comparative myology of the thigh and crus in the salamanders Ambystoma tigrinum and Dicamptodon tenebrosus (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 147-163 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Variation in myology of the hind limb among salamanders has been poorly characterized. Nineteen major hind limb muscles of Ambystoma tigrinum (Ambystomatidae) and Dicamptodon tenebrosus (Dicamptodontidae) were studied to provide baseline descriptive data on hind limb myology in salamanders and to generate hypotheses of hind limb muscle function. Most superficial muscles of the hind limbs span multiple joints, including a unique three-joint muscle, the ischioflexorius, that extends from the pelvic girdle to the plantar fascia. The deeper hind limb muscles spen single joints. No myological diffrences were observed between the hind limbs of A. tigrinum larvae and individuals that had just metamorphosed. Fully adult tiger salamanders that had been housed in terraria for many years had hypertrophied femorofibularis and ischiofemoralis muscles, a condition similar to that reported in Paramesotriton and Taricha, which engage in terrestrial locomotion. In contrast, adults of D. tenebrosus, which are also good walkers, possess a hypertrophied ischioflexorius muscle and a reduced femorofibularis. These regular myological diffences, and those described by previous workers for different salamnder taxa, may be associated with differences in life-history traits, and in the case of A. tigrinum, with patterns of muscle use.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052110204
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  • 117
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    Histochemical study of jaw muscle fibers in the American alligator (Alligator mississippiensis) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 187-199 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Seven jaw muscles of the American alligator have been analyzed for histochemical characteristics of their fiber types: Musculus depressor mandibulae (MDM), M. pseudotemporalis (MP), M. adductor mandibulae posterior (MAMP), M. adductor mandibulae externus (MAME, profound and superficial portions), M. intramandibularis (MI), M. pterygoideus anterior (MPta), and M. pterygoideus posterior (MPtp). Classification of muscle fibers in previous studies has been based on (1) the staining properties of myosin ATPase after alkaline and acid preincubations and (2) the staining reactions for SDH, α-GPDH, PAS, and myosin ATPase after alkaline preincubations. In this study fiber types in one group of muscles (MP, MAMP, profound portion of MAME and MI) are classified (1) as type I, IIa, or IIb fibers, according to the system of Brooke and Kaiser (Arch. Neurol. 23:369-379, '70) or (2) as fast twitch glycolytic (FG), fast oxidative glycolytic (FOG), slow oxidative (SO), and tonic (few in number) fibers, according to the system of Putnam et al. (J. Exp. Zool. 214:303-309, '80). A second group of muscles (MDM, MAME superficial portion, MPta, and MPtp) reacted differently in similar histochemical tests and are classified, respectively, as (1) types 1, 2, 3 or (2) types A, B, C. We have distinguished the fiber types as red, intermediate, white, and tonic in analyses on muscle sections. The highest percentage of red and intermediate fibers is found in the MI. All three fiber types are approximately equal in superficial and medial portions of the MDM and the MPtp. Three muscles (MP, MAMP, and MAME) have the highest white fiber composition. These results indicate a correlation between the histochemical profiles of individual muscles and their functions during masticatory movements.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110207
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  • 118
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    Ultrastructure of somatic tissues in the ovaries of a chaetognath (Ferosagitta hispida) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 221-241 
    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 ovaries of Ferosagitta hispida contain four somatic tissues. A myoepithelial ovary wall, continuous with a thin layer of peritoneocytes lining the coelomic cavity, encloses a fluid-filled ovarian space in which oocytes develop. Lamellar extensions of a “follicular reticulum” branch throughout the ovarian space and ensheath developing oocytes. This tissue has been overlooked in most previous studies of chaetognath ovaries. A bipartite oviductal complex extends the length of each ovary just within the lateral ovary wall. It consists of a flattened, blindly ending cellular tube, herein referred to as the cellular sheath, and an enclosed syncytium. Sheath cells secrete an electron-dense product into the ovarian space. Those sheath cells directly bordering the syncytium are contractile and are joined to the to the syncytium by gap junctions and microvillar interdigitations. The syncytium contains a complex of membrane-bounded lumina. The latter sometimes enclose sperm received during mating or ovulated eggs. Thus the syncytium serves both as a seminal receptacle and as a duct for passage of eggs to the outside. Contrary to several classical reports, the cellular sheath and syncytium of the oviductal complex do not separate at ovulation to form a temporary oviductal lumen.
    Additional Material: 39 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110211
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    Praesomal nerves in Leptorhynchoides thecatus (Acanthocephala: Rhadinorhynchidae) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 275-284 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Investigated by light microscopy, the nerve pathways are described for the first time in the praesoma of a species of Rhadinorhynchidae. The pathways are described for 18 nerves, eight paired and two single, which originate from the cerebral ganglion and a post-ganglionic cell and terminate in the body wall musculature and the proboscis. The location of three commissures formed by these nerves is also described.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110305
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    The composite structure of quail pectoralis muscle (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 27-35 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The twitch fibers of the quail pectoralis muscle were found to have one neuromuscular junction each, located in the middle third of the fiber. The length of isolated fibers varied between 8.8 and 33.2 mm, with mean and median values of 16 and 15.6 mm, respectively. The lengths of the fascicles from which the fibers were isolated varied between 30 and 51 mm. The muscle fibers taper at both ends. The neuromuscular junctions, revealed after histochemically reacting the intact muscle for acetyl cholinesterase activity, were arranged in discrete bands, separated by intervals of between 0.94 and 6.70 mm, with a mean value of 3.14 mm. The quail pectoralis muscle is thus composed of discontinuous, tapered muscle fibers, arranged in an overlapping series. It is therefore a muscle in which tension is transmitted laterally between muscle fibers.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052120104
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    Functional morphology of the endomysium in series fibered muscles (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 109-122 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Many skeletal muscles, including the feline biceps femoris, are composed of short, tapered myofibers arranged in an overlapping longitudinal series. The endomysium of such muscles transfers tension between overlapping myofibers, and is thus an elastic element in series with them. The endomysium of the cat biceps femoris contains curvilinear collagen fibrils in an approximately isotropic (random) array. The collagen fibrils undergo only a modest reorientation as the myofibers shorten or lengthen within the physiological range. A geometrical model predicts no change in the thickness of the endomysium on changing muscle fiber length and quantifies the expected collagen fibril reorientation in the endomysium as a function of muscle extension. It is also demonstrated that a high proportion of the collagen fibrils will be curvilinear at all sarcomere lengths. The organization of endomysial collagen is appropriate for the transfer of loads between myofibers by means of shear. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052120203
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    Comments on the morphology of the pre-oral spine in Argulus (Crustacea: Branchiura) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 155-162 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A histological study of the pre-oral spine and associated structures in Argulus japonicus reveals that two exceptionally long and slender muscles casuse retraction of the spine into the spinal sheath. Originating from the body wall mid-dorsally the two muscles proceed through the nerve ring and the blood-filled lumen of the spinal sheath before being inserted on a bolster of tissue constituting the base of the spine. Movement of the spinal sheath is affected by two muscles originating from a common apodeme in the dorsal body wall, just posterior to the nauplius eye, and inserted on the lateral walls of the base of the spinal sheath.Two ducts, each leading from a glandular complex in the lateral parts of the carapace, proceed rostrally through the haemocoelic spaces. After passing the tritocerebrum laterally they accompany the retractor muscles of the spine on their course to the base of the spine. Passing through the bolster of tissue at the base of the spine the two ducts run all the way up to the tip of the spine where they open separately.The glandula praeboscoidalis is not associated with the pre-oral spine since its duct runs posteriorly in the wall of the proboscis. The labial spines are associated with giant glandular cells located beneath the optic tracts. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052120206
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992) 
    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.1052120301
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    Middle-ear development: II. Morphometric changes in the conducting apparatus of the chick (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 257-267 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ontogeny of various middle-ear structures was examined in 11 groups of chicks between 10 days embryonic and adult. Measurements of the tympanic membrane surface area and height, columella length, and that of the columella footplate, annular ligament, and oval window area were obtained using video micrographs and computer digitization techniques. The oval window matures first at 53 days post-hatching, whereas the columella achieves adult size at 74 days. The tympanic membrane surface area is the last middle-ear variable studied to reach adult size (79 days post-hatch). The columella increases its length from 0.63 mm (10 days embryonic) to 2.73 mm in the adult. The tympanic membrane area expands by 280% whereas the columellar footplate area increases by 11x. As a result, the pressure amplification of the middle ear due to the tympanic membrane/columellar footplate area ratio improves by over 400%. These data further contribute to our understanding of the functional development of the middle ear. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    Edgeworth's legacy of cranial muscle development with an analysis of muscles in the ventral gill arch region of batoid fishes (Chondrichthyes: Batoidea) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 213-256 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A series of studies by Edgeworth demonstrated that cranial muscles of gnathostome fishes are embryologically of somitic origin, originating from the mandibular, hyoid, branchial, epibranchial, and hypobranchial muscle plates. Recent experimental studies using quail-chick chimeras support Edgeworth's view on the developmental origin of cranial muscles. One of his findings, the existence of the premyogenic condensation constrictor dorsalis in teleost fishes, has also been confirmed by molecular developmental studies. Therefore, developmental mechanisms for patterning of cranial muscles, as described and implicated by Edgeworth, may serve as structural entities or regulatory phenomena responsible for developmental and evolutionary changes. With Edgeworth's and other studies as background, muscles in the ventral gill arch region of batoid fishes are analyzed and compared with those of other gnathostome fishes. The spiracularis is regarded as homologous at least within batoid fishes, but its status within elasmobranchs remains unclear; developmental modifications of the spiracularis proper are evident in some batoid fishes and in several shark groups. The peculiar ventral extension of the spiracularis in electric rays and some stingrays may represent convergence, probably facilitating ventilation and/or feeding in both groups. The evolutionary origin of the “internus” and “externus” remains uncertain, despite the fact that a variety of forms of the constrictor superficiales ventrales in batoid fishes indicates an actual medio-ventral extension of the “externus.” The intermandibularis is probably present only in electric rays. The “X” muscle occurs only in electric rays and is considered to be Edgeworth's intermandibularis profundus. Its association with the adductor mandibular complex in narkinidid and narcinidid electric rays may relate to its functional role in lower jaw movement. Contrary to common belief, in most batoid fishes as well as some sharks, muscles that originate from the branchial muscle plate and extend medially in the ventral gill arches do exist: the medial extension of the interbranchiales in most batoid fishes and some sharks and the “Y” muscle in the pelagic stingrays Myliobatos and Rhinoptera. The latter is another example of the medial extension of the “internus.” Whether the interbranchiales and “Y” muscle are homologous within elasmobranchs and whether homologous with the obliques ventrales and/or transversi ventrales of osteichthyan fishes await further research. Four hypobranchial muscles are recognized in batoid fishes: the coracomandibularis, coracohyoideus, coracoarcualis, and coracohyomandibularis. The coracohyoideus is discrete from the coracoarcualis; its complete structural separation from the latter occurs in several groups of batoid fishes. The sternohyoideus of osteichthyan fishes is regarded as a partially developed, continuous bundle of muscle whose counterpart in chondrichthyan fishes appears to be the fully developed rectus cervicus in holocephalans and the squaloid shark Isistius. The coracoarculais is, therefore, present structurally and possibly functionally as a discrete muscle only in elasmobranchs. Although the coracohyomandibularis has been regarded as unique in batoid fishes, the first coracobranchialis in the sawshark Pristiophorus may represent the coracohyomandibularis. The conceptual frameworks and results of the development and evolution of cranial muscles presented here emphasize the importance of molecular and experimental embryological studies and integration of these areas with comparative anatomical and functional studies. Edgeworth's contributions remain as a remarkable achievement in muscle biology. © 1992 Wiley-Liss, Inc.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052120304
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    Behavior of postcapillary venule pericytes during postnatal angiogenesis (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), 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: Autogeneic bone marrow was implanted into an artificially created cavity in a segment of rat sciatic nerve, after removal of nerve fascicles, without damaging the epineurium or surrounding microcirculation. Under these conditions, the bone marrow induces capillary growth and forms granulation tissue from surrounding tissues, the behavior of pericytes being studied in the preformed (preexisting) postcapillary venules of the latter. Beginning 20 h after bone marrow implantation, the pericytes of the preexisting postcapillary venules hypertrophy, with shortening of their processes, prominent nucleoli, dispersal of ribosomes into their free form, fragmentation of basal lamina, and increased DNA synthesis. The number of contact surfaces between pericytes and endothelium is noticeably lower than in controls. Many pericytes are in mitosis. Cells with a shape transitional between pericytes and interstitial fibroblast-like cells appear. In some cases, Monastral Blue (MB) was used as a marker of the cells in preexisting venule walls of the graft bed. In the earlier stages of the experiment, the MB labelling is restricted to the cytoplasm of pericytes and endothelial cells of postcapillary venules, and to the macrophages that occur in the space between pericytes and endothelium. Furthermore, the marker continues to be observed, at a later stage, in some of the following cells: pericytes and endothelial cells of the newly formed vessels, macrophages migrating into the interstitium, transitional cells between pericytes and fibroblasts, and typical fibroblasts of the granulation tissue. The present study provides greater evidence that preformed microvasculature pericytes are substantially activated during postnatal angiogenesis and granulation tissue formation, suggesting that they may contribute to the origin of new pericytes and fibroblasts. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052130105
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    Morphological corollaries and ecological implications of flightlessness in the kakapo (Psittaciformes: Strigops habroptilus) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 105-145 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphological corollaries of flightlessness of the kakapo (Strigops habroptilus) have been studied using skin specimens, skeletons, and pectoral dissection of an anatomical specimen. These have been compared with the closely related, flighted kea (Nestor notabilis), and secondarily with other Psittaciformes and the convergent hoatzin (Cuculiformes: Opisthocomus hoazin). S. habroptilus is the most massive and sexually dimorphic psittaciform in the world, and has the smallest relative wing size of any parrot. Alar pterylography of S. habroptilus is similar to that of other parrots, but remiges of the species are shorter, comparatively rounded, show less asymmetry of vanes, and have fewer interlocking barbules distally. S. habroptilus shows peculiarities of the sternum (vestigial carina, shortened spina externa), coracoid (elongate processus lateralis, enlarged angle with scapula), and humerus (prominent tuberculum ventrale, undercut crista bicipitalis). Pectoral skeletal dimensions of S. habroptilus are smaller than those of N. notabilis, whereas the reverse is true for pelvic dimensions. Most skeletal dimensions of S. habroptilus are more variable (within sexes) than those of N. notabilis. Proximal wing elements are disproportionately long and distal elements disproportionately short in S. habroptilus. The legs of S. habroptilus are characterized by disproportionately long femora and disproportionately short tarsometatarsi. Distinctive features of the pectoral musculature of S. habroptilus include a greatly reduced Mm. pectoralis thoracica and supracoracoideus, the absence of a distinct proximal muscle belly of M. propatagialis tendo longus, an extensive M. cucullaris capitis clavicularis associated with a voluminous crop, and an essentially tendinous M. sternocoracoideus. Relative to mean body mass, all dimensions of the antebrachial, carpometacarpal, digital, and patagial muscles are smaller in S. habroptilus than in N. notabilis. These aspects are compared to those of other flightless birds. Discussed are implications of flightlessness and associated large body size of S. habroptilus for issues of thermodynamics, metabolism, activity patterns, digestive anatomy, diet, reproduction, and insularit. © 1992 Wiley-Liss, Inc.
    Additional Material: 18 Ill.
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    Ultrastructural changes in guinea pig endometrial cells during the estrous cycle (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 83-96 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the guinea pig, the estrous cycle is characterized by constant measurable level of plasma progesterone with two peaks: the first one associated with the peak of plasma estradiol-17β occurring at proestrus and the second, during diestrus, more pronounced at the time at which the level of estradiol-17β is undetectable. The progesterone receptor content is the highest on day 1 and the lowest on day 10 of the estrous cycle, which lasts 16.3 · 1.5 days (n = 37; mean · SD). There is a positive correlation between the plasma level of estradiol-17β and the progesterone receptors detected immunocytochemically in both endometrial epithelial and stromal cells. The general morphology of the endometrium during prcestrus and estrus is consistent with an estrogenic stimulation, i.e., a smooth and regular surface of the endometrium and the presence of numerous microvilli on the cell surface. However, a moderate secretory activity also occurs in proestrus and estrus. During postestrus, the glandular cells display an increase in characteristic secretory features which parallels the rise of progesterone in the plasma. © 1992 Wiley-Liss, Inc.
    Additional Material: 19 Ill.
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    In memoriam - Professor William L. Nutting (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 121-121 
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    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.1052140109
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    Gill raker structure and development in indo-pacific anchovies (Teleostei: Engrauloidea), with a discussion of the structural evolution of engrauloid gill rakers (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 109-119 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The postlarval development of gill raker denticles is described for the engrauloid (anchovy) genera Coilia, Lycothrissa, Setipinna, Thryssa, Stolephorus, and Encrasicholina based on scanning electron microscopy. The raker structure of adult Papuengraulis is also described. In the coiliid genera Coilia, Lycothrissa, Setipinna, Thryssa, and Papuengraulis, denticle development is not confined to particular region(s) of the raker. With few exceptions, the proliferation of denticles with growth is greatest along the upper raker edge; denticles are smaller and less dense on the raker faces and along the lower raker edge. Some Thryssa and Setipinna have a derived condition of denticle clustering along the upper raker edge. In Stolephorus and Encrasicholina, denticle development is confined to the upper raker half and includes the development of a single row of denticles along each raker face. A phylogenetic analysis of engrauloid raker structure, incorporating data from Bornbusch ( 88: Copeia 1988:174-182) and based on outgroup comparisons, indicates that for the Engrauloidea: (1) the pattern of denticle development shared by coiliids is plesiomorphic; and (2) the pattern of denticle development shared by Stolephorus, Encrasicholina, and most other engraulids is synapomorphic for the Engraulidae. There is no evidence that the studied coiliids Stolephorus and Encrasicholina are suspension feeders. The engraulid pattern of raker denticle development which is retained in suspension feeding engraulids of the genus Engraulis was thus derived before the derivation of suspension feeding in Engraulis. Comparative morphological and phylogenetic studies of clupeomorph raker structures and feeding behaviors can infer the historical origins of morphology-behavior associations, help define possible directions for analyses of raker denticle function, and thereby help elucidate the significance of structure-function couplings in the evolution of such clupeomorph trophic behaviors as suspension feeding. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052140108
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    Morphological adaptations of the respiratory hindgut of a marine echiuran worm (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 131-138 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The echiuran worm Urechis caupo lives in U-shaped burrows in marine mudflats where levels of toxic hydrogen sulfide increase and water becomes hypoxic during low tide. Even in this low oxygen and high sulfide environment, the animal is capable of maintaining aerobic respiration. Gas exchange occures across both the body wall and hindgut. The hindgut functions as a type of water lung and is a thin walled, highly convoluted structure capable of considerable dilatation. It is rhythmically ventilated with water and its role as a respiratory organ becomes increasingly important as ambient pO2 drops. In the deflated hindgut light microscopy reveals a pseudostratified appearing innermost mucosal epithelium composed of columnar cells with nuclei at different levels. When the hindgut is fully inflated, ultrastructural studies show a simple columnar epithelium with the nuclei at the same level. Ultrastructurally, the free surface of the hindgut cells bears numerous microvilli and a few cilia. The lateral cell membranes are highly folded in the deflated hindgut, but these folds are not visible in the fully inflated hindgut. The cytoplasm contains osmiophilic bodies which show a partially lamellated pattern which may be sulfide oxidizing bodies involved in sulfide detoxification. In the fully inflated hindgut, the entire perimeter of the lumenal mucosa is covered by electron dense inclusions, whose exact fuction is unknown. The lack of structural information on the respiratory organ of this echiuran worm renders the interpretation of its morphological and histological features at the ultrastructural level difficult, although the present study has broadened our understanding of the structural adaptations of the hindgut as a respiratory organ. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052140203
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    Malpighian tubules of Formica polyctena (Hymenoptera): Light and electron microscopic study (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 159-171 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The study of semithin (1 μ in thickness) and thin sections of Epon-embedded material reveals that Malpighian tubules of Formica polyctena are composed of a single cellular type throughout their length. No differentiated regions were observed. Ultrastructural traits of the epithelial cells are those of highly metabolic cells engaged in water and ion transport: large euchromatic nucleus, several nucleoli, abundant mitochondria, a conspicuous brush border, and basolateral infoldings. Lysosomes, smooth endoplasmic reticulum, and intercellular junctions are also well developed. Mineral concretions occur within the cells and in the lumen. However, the degree of development of these cytological traits is variable among the different cells. The tubules drain into the gut through a specialized posterior region of the midgut or ampulla. In this region, the epithelial cells, although usually taller and showing conspicuous basal infoldings, display cytological structures similar to those of the Malpighian tubules. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052140206
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    Comparative skeletogenesis of the forearm of the little brown bat (Myotis lucifugus) and the norway rat (Rattus norvegicus) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 251-260 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study describes, quantifies, and compares the growth and development of the volant forelimb morphology of Myotis lucifugus with that of the terretrial forelimb morphology of Rattus norvegicus. In M. lucifugus there is (1) accelerated growth in forearm length after parturition, (2) cessation in growth of the midshaft diameter of the ulna just after the onset of osteogenesis, (3) proximal fusion of the radius and ulna, which results in the radius occupying 97% of the articular surface of the elbow joint in adults, (4) fusion between the cartilaginous distal epiphyses of the radius and ulna which results in formation of a radioulnar bridge that becomes fully ossified in adults, and (5) incomplete ossification of the ulna with a section of the diaphysis becoming ligamentous. None of these events occurs during development in R. norvegicus. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052140302
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    Natural and experimental reduction of the avian fibula: Developmental thresholds and evolutionary constraint (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 269-285 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fibula reduction is a key feature of avian limb evolution. In a combined comparative and experimental approach the present study analyses the trends of fibula reduction in extant birds and their developmental basis. The study of 55 species of birds reveals four different types of tibiotarsus-to-fibula relationships. Extremely small fibulae are associated with two types of limb modification: (1) elongations of the limb primarily affect the tibiotarsus, increasing its length more than that of the fibula; (2) miniaturizations of the limb reduce both tibiotarsus and fibula length, but are reglarly associated with structural reductions of the distal parts of the fibula. True structrual reductions are distinguished from relative size reductions. The specific features of fibula reduction are analyzed through experimental mesenchyme excisions in chick limb buds. The methodical variation of experimental parameters resolves a long-standing controversy about the effects of mesenchyme reductions on the patterns of skeletal formation. Mesenchyme excisions are shown to have unequal effects on the two zeugopod bones, affecting the fibula to a greater degree than the tibiotarsus. Several of the features seen in birds with advanced fibula reductions are paralleled by the effects of mesenchyme reductions. The consequences of this differential susceptibility of the skeletal blastemata are discussed both in terms of pattern formation in limb development and in terms of its bearing on the patterns of evolutionary limb reduction. It is concluded that thresholds of cell number and blastema size in development constrain the patterns of phenotypic variation in avian limbs. © 1992 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052140304
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    Stereotaxic atlas of the brain of Octodon degus (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 299-320 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present a stereotaxic atlas of the brain of the trumpet-tailed rat or degu (Octodon degus), an hystricomorph rodent native to Chile and one which has become increasingly popular as a research animal, among other things because of its use as a model for diabetic catarcts and its tendency to become hyperglycemic. The atlas contains 38 transverse and two sagittal sections of the brain covering pros-, mes-, and rhombencephalon, as well as diagrams of the brain's surface anatomy. It was constructed from brains of young adult male degus but can be used readily in studies of adult females, since there is no apparent sexual dimorphism in the brain size of this rodent. Ninety percent of 40 experimental lesions used to check the accuracy of the atlas were correctly placed.The fore- and midbrain of the degu are generally more compact than corresponding regions of the brain in the laboratory rat (suborder Myomorpha) and the guinea pig (another hystricomorph). The amygdaloid complex extends further forward in the telencephalon. Major mesencephalic nuclei and fiber tracts are more rostral in position. However, superior and inferior colliculi are much longer in degus than rats. The basic organization of the rhombencephalon is similar in degus and rats, although there are clearcut differences in the length or size of some hindbrain nuclei. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052140306
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    Configurations of the rectus abdominis muscle of anuran tadpoles (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 351-356 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Configurations of the rectus abdominis in tadpoles of 60 anuran species in 13 families were examined. This muscle is present by Gosner stage 25 and does not change until late in metamorphosis. The anterior terminus of the r. abdominis usually is a straight, transverse front or fan-shaped array only loosely associated with the rectus cervicis. In some suspension feeders (Rhinophrynus, Xenopus, but not microhylids), macrophagous suction feeders (Lepidobatrachus) and bromeliad inhabitants (Hyla bromeliacia) the r. abdominis is contigous with the r. cervicis which continues anterolaterally and dorsally from the wall of the spiracular cavity. Suctorial forms (Scutiger), those that live in confined spaces (burrowers, Centrolenella; bromeliad inhabitants, Hyla bromeliacia), and the taxa that have the r. cervicis and r. abdominis contiguous all have closed myosepta; the myosepta of other taxa; except for ones with large tadpoles (e.g., Rana catesbeiana), have large gaps between at least anterior myotomes. These initial data suggest that the configurations of the r. abdominis have responded to selection based on ecomorphological function and convergence among lineages are noted. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052140310
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    Oleospheres of the cave-dwelling shrimp Troglocaris schmidtii: A unique mode of extracellular lipid storage (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 31-39 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cave-dwelling shrimp, Troglocaris schmidtii, has a unique mode of lipid storage. The lipid lies extracellularly in specialized compartments of the hepatopancreas, named oleospheres. The lipid is synthesized in the R-cells of the hepatopancreatic epithelium and accumulates in lipid droplets which fuse to form bigger globules. Mature lipid globules display moderately electron dense centers probably comprising triglycerides, and a broad electron dense boundary presumably consisting of lipoproteins. The globules are discharged into the lumen of the hepatopancreatic tubules by a kind of apocrine secretion. There, they coalesce to form larger masses. Finally, these lipid masses are transported into the oleospheres through a valve-like structure. The continual accumulation of lipid results in a drastic expansion of the oleospheres up to 500 μm in diameter. The absence of food in the digestive tract and the inactivity of the digestive enzyme producing F-cells indicate that digestion is suspended in the period of oleosphere formation. The curious mode of lipid storage in T. schmidtii may represent an adaptation to the extreme environmental conditions of a cave.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110105
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    Pigment pattern formation in larval ambystomatid salamanders: Ambystoma tigrinum tigrinum (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 73-85 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have begun a comparative study of pigment patterns and their mechanisms of formation in ambystomatid salamanders in an attempt to elucidate the evolution of these traits in this family. In Ambystoma t. tigrinum, the migration of the prospective pigment cells was followed by using scanning electron microscopy and light microscopy combined with markers (dopa incubation for detecting melanophores, ammonia-induced pterin fluorescence for detecting xanthophores). The pigment pattern resulting from the cell migration shares features both with the alternating vertical xanthophore and melanophore bars of A. mexicanum and the horizontal stripes of certain salamandrids and ambystomatids. The pigment pattern of A. t. tigrinum is interpreted here as an intermediate evolutionary step between a primitive horizontal stripe pattern and a derived vertical bar pattern. The initiation of pigment pattern formation resembles the situation in A. mexicanum, probably reflecting the close phylogenetic relationship between the two taxa.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110109
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    Cranial ontogeny in the direct-developing frog, Eleutherodactylus coqui (anura: Leptodactylidae), analyzed using whole-mount immunohistochemistry (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 95-118 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Direct development in amphibians is an evolutionarily derived life-history mode that involves the loss of the free-living, aquatic larval stage. We examined embryos of the direct-developing anuran Eleutherodactylus coqui (Leptodactylidae) to evaluate how the biphasic pattern of cranial ontogeny of metamorphosing species has been modified in the evolution of direct development in this lineage. We employed whole-mount immunohistochemistry using a monoclonal antibody against the extracellular matrix component Type II collagen, which allows visualization of the morphology of cartilages earlier and more effectively than traditional histological procedures; these latter procedures were also used where appropriate. This represents the first time that initial chondrogenic stages of cranial development of any vertebrate have been depicted in whole-mounts.Many cranial cartilages typical of larval anurans, e.g., suprarostrals, cornua trabeculae, never form in Eleutherodactylus coqui. Consequently, many regions of the skull assume an adult, or postmetamorphic, morphology from the inception of their development. Other components, e.g., the lower jaw, jaw suspensorium, and the hyobranchial skeleton, initially assume a mid-metamorphic configuration, which is subsequently remodeled before hatching. Thirteen of the adult complement of 17 bones form in the embryo, beginning with two bones of the jaw and jaw suspensorium, the angulosplenial and squamosal. Precocious ossification of these and other jaw elements is an evolutionarily derived feature not found in metamorphosing anurans, but shared with some direct-developing caecilians. Thus, in Eleutherodactylus cranial development involves both recapitulation and repatterning of the ancestral metamorphic ontogeny. These modifications, however, are not associated with any fundamental change in adult morphology and cannot at this time be causally linked to the evolutionary success of this extraordinarily speciose genus.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110111
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    Spermatozoon structure of eight species of South African holothurians (Echinodermata) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 179-186 
    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 of the spermatozoa of eight species (from seven genera) of holothurians has shown that each species has a sperm with unique dimensions, indicating that spermatozoon morphology can be used as a taxonomic character. However, although the structure of the sperm is species-specific, all sperm have a similar appearance which is typical of holothurians. The sperm head is composed of a spheroidal nucleus (about 2 μm diameter) which has a large anterior fossa housing the approximately spherical acrosome. The acrosome is differentiated internally and surrounded by periacrosomal material. The mid-piece consists of a single mitochondrion with lamellar cristae which surrounds the eccentrically positioned centrioles. The conservative form and arrangement of the sperm organelles suggest that sperm morphology cannot be used for phylogenetic investigations within this taxon.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110206
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    Ultrastructure of otolith increments and checks in the teleost fish Oreochromis niloticus (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 213-220 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An otolith increment is composed of an incremental zone and a discontinous zone. Observation of the otoliths of Oreochromis niloticus with transmission and scanning electron microscopy reveals that organic fibers are concentrated in the discontinuous zone and are relatively scarce in the incremental zone. On the other hand, calcium carbonate crystals are chiefly packed in the incremental zone and are less dense in the discontinuous zone. Both fibers and crystals are oriented perpendicular to the growth increments. Otolith checks, or discontinuities, contain even denser fibers and fewer fine crystals than does the discontinuous zone. A higher proportion of individual fibers is prominently stained in the discontinuous zone and check than in the incremental zone. Other features of individual fibers appear to be the same among the three zones. The crystals on either side of a check or a discontinuous zone resemble each other both in size and orientation. Zonation of protein and mineral components of otoliths can be understood in terms of both incremental growth and the daily cycle of deposition.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110210
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    An ultrastructural study on the origin of glomerulocytes, a type of blood cell in a styelid ascidian, Polyandrocarpa misakiensis (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 269-273 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The glomerulocyte is a type of blood cell in the compound ascidian, Polyandrocarpa misakiensis. It is a discoidal cell, measuring 12-13 μm in diameter and about 3 μm in thickness. The outer half of the cell is occupied by concentrically-arranged fibers, usually 0.2-0.3 μm thick; the nucleus and organelles are confined to the central cytoplasm. The ordinary epidermal cells are columnar and are characterized by an apical homogeneous cytoplasmic bulge, vesicular bodies in the cytoplasm, and juctions between them. Growing or immature glomerulocytes are found only in the epidermis. They have intracellular fibers and vesicular bodies, and there are juctions between them and epidermal cells. These facts strongly suggest the origin of the glomerulocyte from an epidermal cell. However, no definite statement can be made as yet because earliest stages of differentiation have not been observed. The glomerulocyte fully differentiated in the epidermis is apparently released into the hemocoel.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110304
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    Internal reproductive system in adult males of the genus Camponotus (Hymenoptera: Formicidae: Formicinae) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 307-317 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Descriptions are provided of the histology and ultrastructure of the male internal reproductive tracts from three species of Camponotus, representing three subgenera. This study is the first to provide ultrastructural information on the testes (including spermatogenesis and spermiogenesis), seminal vesicles, and accessory glands in ants. Testes contain about ten follicles each, and each follicle is capable of producing hundreds of cysts in which spermatozoa develop. Structural evidence of meiosis in late pupal testes includes cytoplasmic bridges between spermatocytes, centriole elimination, and fusion of mitochondria. Developing spermatids are in close contact with cyst cells in the region of the acrosome. Mature spermatozoa are similar in ultrastructure to those described previously for two other subfamilies of ants (Myrmicinae and Dolichoderinae). The ultrastructure of the seminal vesicle suggests that it is not merely a passive organ for sperm storage. Large numbers of both mitochondria and membranous whorls suggest a pH-regulating and/or hormonal function. The accessory gland is made up of secretory cells that contain a diversity of secretory granules. SDS-PAGE reveals several proteins found in the accessory glands but absent in the adjacent genitalia. Preliminary analyses indicate that carbohydrate is an important component of accessory gland secretions.
    Additional Material: 23 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110308
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    Morphology of the tooth of the American alligator (Alligator mississippiensis): The fine structure and elemental analysis of the cementum (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 319-329 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure and the concentration of trace elements in the cementum layer in functional teeth of subadult alligators (ca. 120 cm to 160 cm total length) was studied by using scanning electron microscopy (SEM), microradiography, and electron microprobe analysis (EMPA). The cementum layer was hypertrophic and consisted of two layers: the fibrous layer and the calcified layer. The two layers undergo developmental changes as a result of resorption and replacement. During the tooth replacement in the American alligator, trace elements decreased at the base of the dentine layer; the resorption of the alveolar bone occurred simultaneously at the tooth socket. We concluded that the resorption of the cementum in the alligator provided a useful indication of the mechanism of tooth replacement in crocodilian.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052110309
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    Fine structure of the dorsal lingual epithelium of the little tern, Sterna albifrons pallas (Aves, Lari) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 13-26 
    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 surface of the tongue of the little tern, Sterna albifrons, has a distinctive anterior region for five-sixths of its length and a terminal posterior region. The anterior region observed by scanning electron microscopy is distinguished along its forward half by a median line from which median papillae protrude. The hind half of the anterior region has a median sulcus without papillae. The deciduous epithelium on both sides of the median line and sulcus bears scattered epithelial protrusions. The posterior lingual region has neither median papillae nor deciduous epithelium. So-called giant conical papillae are located in a transverse row between anterior and posterior regions. Delicate microridges adorn the surfaces of all outer epithelial cells in both regions.Examination of the dorsal lingual epithelium by light and electron microscopy provides histologic and cytologic criteria for distinguishing anterior and posterior regions. Basal cells are nearly alike throughout the dorsal epithelium. Intermediate layer cells of the anterior region contain numerous tonofibrils in electron-dense bundles composed of 10 nm tonofilaments. The outer layer is composed of electron-dense, well-keratinized cells, and electron-lucent epithelial protrusions are present on the expose surface of the outermost cells. Median papillae are composed of typical keratinized cells, which are nearly filled with keratin filaments. Intermediate layer cells in the posterior region of the tongue are nearly filled with unbundled tonofilaments. There is only a very thin outer keratinized layer in this region.
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    URL: http://dx.doi.org/10.1002/jmor.1052120103
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    Figures of Eberth in the amphibian larval epidermis (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 87-97 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Figures of Eberth are prominent extensive filamentous structures in the basal epidermal cells of larval amphibians. They are compared and contrasted qualitatively and quantitatively in a number of species of the three groups of living amphibians.Fully developed Figures consist of massive skeins of tonofilaments oriented in three dimensions and hinged on hemidesmosomes within the cell. The overall appearance of the Figures is similar in anurans, urodeles and Ichthyophis among the apodans. However, in terms of size and number per unit length of the proximal cell margin, the hemidesmosomes and the thickness or their emergent skeins in anurans and Ichthyophis differ significantly from those parameters in urodeles, a feature that is presumably independent of cell size. Figures are poorly developed or missing in embryos of Typhlonectes, which has no larval stage in its life history.These ubiquitous skeletogenous structures in the aquatic larval amphibians, among other things, could be protective of underlying delicate tissues and act as a stabilizer in bodily movement during swimming. They could also serve as a reserve of cytokeratin for use during later cellular division and sloughing.
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    Unusual cuticle-associated organs in the heterotardigrade, Echiniscus viridissimus (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 123-140 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Echiniscus viridissimus possesses two organs that lie above the ventromedial body wall approximately at the level of the second and third pair of legs. Each organ is composed of one medial and two lateral cells and possesses a pair of convoluted ducts. The lateral cells produce and release profuse amounts of filamentous basement membrane-like material into the body cavity. The proliferated material persists en masse adjacent to the lateral cells and is associated with disrupted droplets of pigmented body cavity material (BCM). The medial cell is larger than the lateral cells and possesses numerous tubular invaginations in which droplets of BCM are frequently found. Each duct originates as an infold that becomes a simple channel in the lateral cell and continues through the medial cell in a deep groove covered by a long process of the lateral cell. Although the ducts lie on the medial cell surface, they are “internalized” at the base of deep clefts and isolated from the body cavity by “tight” zonulae adherentes junctions. In the medial cell the ducts have a cuticle-like lining and the associated plasma membrane is characterized by numerous saccular infolds containing flocculent material. The duct linings, which extend beyond the limits of the medial cell, project into the endocuticle and terminate on the lateral body wall. Because the lateral cells are producing and releasing profuse basement membrane and because material with an electron density similar to BCM is present in the saccules, the distal regions of the ducts and in the endocuticle, we propose (1) that the lateral cells are producing basement membrane to disassociate BCM and (2) that the medial cell is absorbing and via its ducts translocating that BCM to the endocuticle. Furthermore, because the medial cell exhibits characteristics of transporting epithelia, namely numerous tubular infolds of the outer surface, a layer of distended saccules surrounding the duct and a high density of mitochondria, we suggest that the medial cell also functions in ion or osmotic regulation. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052120204
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    Incorporation of fluorescently labeled contractile proteins into freshly isolated living adult cardiac myocytes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 111-122 
    Details
    ISSN: 0886-1544
    Keywords: cardiac muscle ; actin dynamics ; α-actinin ; vinculin ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When fluorescently labeled contractile proteins are injected into embryonic muscle cells, they become incorporated into the cells' myofibrils. In order to determine if this exchange of proteins is unique to the embryonic stage of development, we isolated adult cardiac myocytes and microinjected them with fluorescently labeled actin, myosin light chains, α-actinin, and vinculin. Each of these proteins was incorporated into the adult cardiomyocytes and was colocalized with the cells'native proteins, despite the fact that the labeled proteins were prepared from noncardiac tissues. Within 10 min of injection, α-actinin was incorporated into Z-bands surrounding the site of injection. Similarly, 30 sec after injection, actin was incorporated into the entire I-bands at the site of injection. Following a 3-h incubation, increased actin fluorescence was noted at the intercalated disc. Vinculin exchange was seen in the intercalated discs, as well as in the Z-bands throug hout the cells. Myosin light chains required 4-6 h after injection to become incorporated into the A-bands of the adult muscle. Nonspecific proteins, such as fluorescent BSA, showed no association with the myofibrils or the former intercalated discs. When adult cells were maintained in culture for 10 days, they retain the ability to incorporate these contractile proteins into their myofibrils. T-tubules and the sarcoplasmic reticulum could be detected in periodic arrays in the freshly isolated cells using the membrane dye WW781 and DiOC3[3], respectively. In conclusion, the myofibrils in adult, as in embryonic, muscle cells are dynamic structures, permitting isoform transitions without dismantling of the myofibrils.
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    URL: http://dx.doi.org/10.1002/cm.970210204
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    Human cardiac and skeletal muscle spectrins: Differential expression and localization (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 293-304 
    Details
    ISSN: 0886-1544
    Keywords: erythroid spectrin ; non-erythroid spectrin ; Z-line ; membrane ; neuromuscular junction ; developmental changes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe multiple human cardiac and skeletal muscle spectrin isoforms. Cardiac muscle expresses five erythroid α,β spectrin-reactive isoforms with estimated MR's of 280, 274, 270, 255, and 246 kD, respectively At least one nonerythroid α-spectrin of MR 284 kD is expressed in heart. While skeletal muscle shares the 280, 270, and 246 kD erythroid spectrins, it expresses an immunologically distinct 284 kD nonerythroid α-spectrin isoform. The 255 kD erythroid β-spectrin isoform is specific for cardiac tissue. By immunocytochemistry, both erythroid β- and nonerythroid α-spectrins are localized to costameres, the plasma membrane, and the neuromuscular junctional region.
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    URL: http://dx.doi.org/10.1002/cm.970210405
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    Colchicine-binding sites of brain tubulins from an Antarctic fish and from a mammal are functionally similar, but not identical: Implications for microtubule assembly at low temperature (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 272-280 
    Details
    ISSN: 0886-1544
    Keywords: cold-stable microtubules ; cold adaptation ; cytoskeleton ; antimitotic drugs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The tubulins of Antarctic fishes possess adaptations that favor microtubule for mation at low body temperatures (Detrich et al.: Biochemistry 28:10085-10093, 1989). To determine whether some of these adaptations may be present in a domain of tubulin that participates directly or indirectly in lateral contact between microtubule protofilaments, we have examined the energetics of the binding of colchicine, a drug thought to bind to such a site, to pure brain tubulins from an Antarctic fish (Notothenia gibberifrons) and from a mammal (the cow, Bos taurus), At temperatures between 0 and 200C, the affinity constants for colchicine binding to the fish tubulin were slightly smaller (1.5-2.6-fold) than those for bovine tubulin. van't Hoff analysis showed that the standard enthalpy changes for colchicine binding to the two tubulins were comparable (δH° = + 10.6 and + 7.4 kcal mol-1 for piscine and bovine tubulins, respectively), as were the standard entropy changes (δS° = +61.3 eu for N. gibberifrons tubulin, +51.2 eu for bovine tubulin). At saturating concentrations of the ligand, the maximal binding stoichiometry for each tubulin was ∼ 1 mol colchicine/mol tubulin dimer. The data indicate that the colchicine-binding sites of the two tubulins are similar, but probably not identical, in structure. The apparent absence of major structural modifications at the colchicine site suggests that this region of tubulin is not involved in functional adaptation for low-temperature polymerization. Rather, the colchicine site of tubulin may have been conserved evolutionarily to serve in vivo as a receptor for endogenous molecules (i.e., “colchicine-like” molecules or MAPs) that regulate microtubule assembly.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210403
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992) 
    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.970220101
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    Different assembly properties of cod, bovine, and rat brain microtubules (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 305-312 
    Details
    ISSN: 0886-1544
    Keywords: tubulin ; acetylated detyrosinated tubulin ; estramustine phosphate ; heparin ; poly-L-aspartic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Assembly properties of cod, bovine, and rat brain microtubules were compared. Estramustine phosphate, heparin, poly-L-aspartic acid, as well as NaCl, inhibited the assembly and disassembled both bovine and rat microtubules by inhibition of the binding between tubulin and MAPs. The assembly of cod brain microtubules was in contrast only marginally affected by these agents, in spite of a release of the MAPs. The results suggest that cod tubulin has a high intrinsic ability to assemble. This was confirmed by studies on phosphocellulose-purified cod tubulin, since the critical concentration for assembly was independent of the presence or absence of MAPs. The results show therefore that cod brain tubulin has, in contrast to bovine and rat brain tubulins, a high propensity to assemble under conditions which normally require the presence of MAPs.Even if cod MAPs, which have an unusual protein composition, were not needed for the assembly of cod microtubules, they were able to induce assembly of bovine brain tubulin. Both cod and bovine MAPs bound to cod microtubules, and bovine MAPI and MAP2 bound to, and substituted at least the 400 kDa cod protein. This suggests that the tubulin-binding sites and the assembly-stimulatory ability of MAPs are common properties of MAPs from different species, independent of the tubulin assembly propensity.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210406
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  • 153
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    Microtubule assembly protects the region 28-38 of the β- tubulin subunit (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 25-37 
    Details
    ISSN: 0886-1544
    Keywords: tubulin structure ; microtubule ; antibody ; microtubule poison ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Polyclonal antibodies have been raised against the peptide 28-38 of the β-subunit of the tubulin heterodimer in order to study the accessibility of this region in the tubulin heterodimer and in various tubulin assemblies. These antibodies were specific for all β'-tubulin subunits, except for β-tubulin isotypes, and did not recognize the α-tubulin subunit. The 28-38 region does not play a role in the interaction between the α-and β-subunits since it was accessible to the antibodies on the native heterodimer. The accessibility of the antibodies was not modified by several microtubular poisons. In contrast, in all tubulin assemblies obtained in the presence of microtubule associated proteins, the region 28-38 was not available to the antibodies. These antibodies did not react with microtubules or tubulin spirals assembled either from microtubule proteins or from pure tubulin when these tubulin assemblies were probed in the absence of free tubulin after centrifugation on glass coverslips. In addition, antibodies failed to interact with the microtubule cytoskeleton in cultured Ptk2 cells indicating that the 28-38 region of β-tubulin is also protected in cellular structures. These observations suggest that the 28-38 region of the β-tubulin subunit is either located in a zone of interaction between two successive tubulin dimers within a protofilament or hidden by an allosteric conformational change which occurs during tubulin assembly. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220104
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  • 154
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    Extension of filopodia by motor-dependent actin assembly (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 160-169 
    Details
    ISSN: 0886-1544
    Keywords: actin polymerization ; myosin ; filament disassembly ; growth cones ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A variety of mechanisms have been proposed to explain the forward extension of cytoplasm in advancing cells and axonal growth cones, including actin polymerization and osmotic swelling. Based on our observations of the filopodia of cultured neuronal growth cones, we propose a mechanism involving motor-induced extension and retraction. We observed that filopodia (actin-based protrusions 0.2-0.5 μ in diameter) extend and retract from growth cone lamellae at the same rate. Further, force is generated at the tips of filopodia which is sufficient to produce compressive buckling of the proximal portion of the filopodium. From our analysis of these movements we suggest that a motor protein powers both the extension and retraction of filopodia. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220303
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  • 155
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992) 
    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.970210301
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  • 156
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    Characterization of tetramethylrhodaminyl-phalloidin binding to cellular F-actin (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 147-158 
    Details
    ISSN: 0886-1544
    Keywords: depolymerization ; DNase I ; association rate constant ; dissociation rate constant ; polymor-phonuclear leukocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent derivatives of phallcidin are widely used to measure filamentous actin (F-actin) levels and to stabilize F-actin. We have characterized the kinetics and affinity of binding of tetramethylrhodaminy (TRITC)-phalloidin to rabbit skeletal muscle F-actin and to F-actin in lysates of rabbit polymorphonuclear leukocytes (PMNs). We have defined conditions where TRITC-phalloidin can be used to inhibit F-actin depolymerization and to quantify F-actin without prior fixation. By equi librium measurements, the affinity of TRITC-phalloidin binding to rabbit skeletal muscle F-actin (pyrene labeled) or to PMN lysate F-actin was 1-4 × 10-7 M. In both cases, the stoichiometry of binding was approximately 1:1. Kinetic measurements of TRITC-phalloidin binding to PMN lysate F-actin resulted in an association rate constant of 420 ± 120 M-1 sec-1 and a dissociation rate constant of 8.3 ± 0.9 ± 10-5 sec-1. The affinity calculated from the kinetic measurements. (2 ± 1 × 10-7 M) agreed well with that obtained by equilibrium measurements. The rate with which 0.6 μM TRITC-phalloidin inhibited 0.1 μM pyrenyl F-actin depolymerization (90% inhibition in 10 sec) was much faster than the rate of binding to pyrenyl F-actin (〈1% bound in 10 sec), suggesting that phalloidin binds to filament ends more rapidly than to the rest of the filament. We show that TRITC-phalloidin can be used to measure F-actin levels in cell lysates when G-actin is also present (i.e., in cell lysates at high concentrations) if DNase I is included to prevent phalloidin-induced polymerization.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210208
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    Cytokinesis is more rapid in Ha-T24-ras transfected rat embryo fibroblasts than in non-transfected control cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 159-166 
    Details
    ISSN: 0886-1544
    Keywords: neoplastic cells ; mitotic cells ; metaphase ; protein kinase C ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It has long been known that neoplastic cells are characterized by increases in cell motility. Earlier studies from this laboratory indicated that rnitotic events were also altered in many tumor and experimentally transformed cells and that this included increases in metaphase duration and a reduction in the duration of cytokinesis. The studies presented in this paper were done to determine whether or not transfection of normal rat embryo fibroblasts by the Ha-T24-ras oncogene could also produce such alterations in mitotic events. The results obtained with the use of time lapse video microscopy indicate that neither the duration of metaphase nor the rate of chromosome movement during anaphase was altered but that the rate of furrow progression during cytokinesis occurred at a significantly more rapid rate. Thus, the cellular alteratioons induced by transfection with Ha-T24-ras accelerate microfilament-dependent cytokinetic furrowing without significant effects on microtubule-dependent mitotic events. One of several possible mechanisms that could account for these observations involves a down regulation of protein kinase C which has been reported to occur in many neoplastic cells including those transformed by ras. Such a hypothesis could also have broader implications because it may be applicable to the increase in motility and metastatic activity generally observed in transformed cells.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210209
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  • 158
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    End-stabilized microtubules observed in vitro: Stability, subunit interchange, and breakage (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 171-186 
    Details
    ISSN: 0886-1544
    Keywords: stable microtubules ; tubulin ; axonemes ; video-enhanced DIC microscopy ; microtubule poisons ; colchicine ; podophyllotoxin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report a reliable method to prepare, in vitro, microtubules that are stabilized at both ends by axonemal structures, and report studies of their properties. Such “end-stabilized” microtubules neither grow nor shorten over times of several hours when tubulin subunits are present in the surrounding solution. When sub-units are removed, the microtubules eventually break. Breakage occurs within a sinuous and flexible region a few microns in length, that begins at a single point on the microtubule and grows. When breakage does occur, the resulting two free ends shorten very rapidly until the flexible part has depolymerized and the region of straight microtubule is reached. The remainder of the microtubule then shortens at rates comparable to those ordinarily observed in dynamic instability. Formation of the flexible region can be reversed if subunits are added to the buffer prior to breakage. End-stabilized microtubules are a useful tool for studying interactions of molecules with the microtubular wall. They may be a good model for interpreting stabilizing events that happen in the cell. A preliminary study of the effects of microtubule poisons on the wall is presented.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210302
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    Reactivation of newt lung cilia: Evidence for a possible temperature- and MgATP-induced activation mechanism (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 187-198 
    Details
    ISSN: 0886-1544
    Keywords: amphibian ; respiratory ; axonemes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Optimal conditions have been developed for the isolation and reactivation of highly coupled, demembranated ciliary axonemes from newt lungs [Hard, Cypher, and Schabtach, 1988, Cell Motil. Cytoskeleton 10:271-284]. In the present study, the motility of these cilia was further characterized by examining the effects of nucleotides, divalent cations, and temperature on beat frequency. When exposed to a reactivating solution containing Mg2+ and ATP, nearly 100% of the axonemes were motile and beat at frequencies of 0-50 Hz, depending on [MgATP] and temperature. Divalent cations were required for movement, with Mg2+ 2-3 times more effective than Ca2+. There was no absolute requirement for Ca2+ for motility. The beat frequencies obtained with fixed ATP and varying Mg2+ concentrations indicate that MgATP serves as the actual substrate. The effects of MgATP on beat frequency depended on the degree of mechanochemical coupling and temperature and MgATP-induced transition between two distinct states whose maximum beat frequencies differ by 200-300%.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210303
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  • 160
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    Reactivation of outer-arm-depleted lung axonemes: Evidence for functional differences between inner and outer dynein arms in situ (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 199-209 
    Details
    ISSN: 0886-1544
    Keywords: amphibian ; respiratory ; cilia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Demembranated axonemes isolated from newt lung ciliated cells show a complex beat frequency response to varying [MgATP] and temperature [Hard and Cypher, 1992, Cell Motil. Cytoskeleton 21:187-198]. The present study was undertaken to ascertain whether the beat frequency of outer-arm-depleted newt lung axonemes is controlled in a manner similar to that of intact axonemes. Populations of demembranated ciliary axonemes were isolated by Triton X-100 extraction of lungs from the newt, Taricha granulosa. Aliquots of the demembranated axonemes were further treated with solutions containing high salt (0.375 M KCl) and 1.25 mM MgATP. This treatment resulted in the selective removal of outer dynein arms and a concomitant decrease in beat frequency to a stable level, 33-35% of control values. The effects of pH, salt concentration, nucleotides, and temperature on the beat frequency of reactivated outer-arm-depleted axonemes were ascertained and compared with those of intact axonemes. Some reactivation properties, such as nucleotide specificity, the effect of pH on beat frequency and the threshold [MgATP] required for reactivation (approximately 5 μM) were similar to those observed for intact axonemes. Other properties, such as the relationship between beat frequency and varying [MgATP] or salt concentration, differed both qualitatively and quantitatively from those of control axonemes, as did their response to temperature over the range, 5°-32°C. The nature of the results obtained with temperature and MgATP suggests that inner and outer dynein arms are not functionally equivalent in situ.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210304
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  • 161
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992) 
    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.970210401
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  • 162
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    Fertilization alters the orientation of pigment granule saltations in Arbacia eggs (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 223-234 
    Details
    ISSN: 0886-1544
    Keywords: actin ; acidic vesicles ; Ca2+ ; pH ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Unfertilized eggs of the sea urchin Arbacia punctulata contain pigment granules distributed throughout their cytoplasm. During the first 15 minutes after fertilization, these vesicles move out to the cortex where they become firmly anchored. We have used time-lapse video differential interference microscopy to analyze the motility of these organelles in unfertilized and fertilized Arbacia eggs. Pigment granules exhibit saltatory movement in both unfertilized and fertilized eggs. Quantitation of vesicle saltations before and after fertilization demonstrates that while there is no significant difference in the speed or pathlength of vesicle movement, there is a dramatic change in the orientation of these saltations. Saltations in the unfertilized egg are very non-radial and are as likely to be directed toward the cortex as away. In contrast, saltations in the fertilized egg are more radially oriented and more likely to be cortically directed. This transition must reflect underlying changes in the cellular structures necessary for pigment granule saltations. The change in the orientation of pigment granule saltations following fertilization requires both a transient increase in the cytoplasmic concentration of Ca2+ and an elevation of cytoplasmic pH. Similarly, the ability of pigment granules to adhere to the cortex requires both the transient elevation of cytoplasmic Ca2+ and the alkalinization of the cytoplasm. As the reorganization of cortical actin at fertilization is regulated by these ionic fluxes, and both movement and adhesion are sensitive to cytochalasins, we hypothesize that the alterations in directed motility and adhesion reflect underlying changes in the actin cytoskeleton.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210306
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    Actin-dependent myoid elongation in teleost rod inner/outer segments occurs in the absence of net actin polymerization (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 235-251 
    Details
    ISSN: 0886-1544
    Keywords: actin polymerization ; cell elongation ; photoreceptor ; cytoskeleton ; phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the retinas of teleost fish, rod photoreceptors elongate in response to light. Light-activated elongation is mediated by the myoid of the rod inner segment and is actin-dependent. Inner segment F-actin filaments form bundles running parallel to the cell's long axis. We examined the mechanism of rod elongation using mechanically-detached rod fragments, consisting of the motile inner segment and sensory outer segment (RIS-ROS). When RIS-ROS are isolated from darkadapted green sunfish and cultured in the light, they elongate 15μm at 0.3-0.6μm/min. Elongation was inhibited 65% by 0.1μM Cytochalasin D, suggesting a requirement for actin assembly. To determine the extent of assembly during elongation, we used three approaches to measure the F-actin content in RIS-ROS: detection of pelletable actin by SDS-PAGE after detergent-extraction of RIS-ROS; quantification of fluorescein-phalloidin binding by fluorimetry, fluorescence-activated cell sorting and image analysis; estimation of total F-actin filament length by electron microscopy. All three assays indicated that no net assembly of RIS-ROS F-actin accompanied myoid elongation. An increase in F-actin content within the elongated myoid was counterbalanced by a decrease in F-actin content within the 13 microvillus-like calycal processes located at the end of the inner segment opposite to the growing myoid. O'Connor and Burnside (Journal of Cell Biology 89:517-524, 1981) showed that minus-ends of rod F-actin filaments are oriented towards the elongating myoid while plus-ends are oriented towards the shortening calycal processes. Our observations suggest that RIS-ROS elongation entails actin polymerization at the minus-ends of filaments coupled with depolymerization at the filament plus-ends.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210307
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    Reversible intracellular ATP changes in intact rat spermatozoa and effects on flagellar sperm movement (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 210-222 
    Details
    ISSN: 0886-1544
    Keywords: bioluminescence ; ATP depletion ; motility ; flagellum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The initiation of motility and modification of energy metabolism of rat caudal epididymal spermatozoa can be induced by dilution in a saline medium. We have investigated in these cells the relationships between the energy reserve (sperm ATP content measured by bioluminescence) and flagellar movement (high speed videomicrography, 200 frames/sec). A steady state was observed in sperm ATP content, progressive velocity (Vp) and flagellar beat frequence (F) with sperm dilution in a medium with glucose, lactate, pyruvate and acetate substrates after 30 minutes of incubation, without these substrates, changes in metabolic pathways occurred immediately and initially disturbed the relationship between ATP levels and F, suggesting differences in motility initiation when energy is from an endogenous origin via mitochondrial oxidative phosphorylation. This “energy crisis” was reversed by the addition of substrates to the medium.The three-dimensional flagellar movement observed in the presence of substrates quickly became two-dimensional in their absence. The flagellar beat envelope became more splayed, the mean amplitude of lateral head displacement increased and F decreased. The resulting high flagellar beat efficiency can be compared to that observed during hyperactivation which is a physiological event related to a fall in intracellular ATP level. In both media, the displacement of the flagellum in relation to the wave axis varied sinusoidally. The sine period increased with time when the spermatozoa were incubated in the medium without substrates. These results suggest a gradual slowing-down of the velocity of wave formation in the proximal part of the flagellum.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210305
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    Dynamics of polar filament discharge and sporoplasm expulsion by microsporidian spores (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 38-50 
    Details
    ISSN: 0886-1544
    Keywords: cytomechanics ; invasion mechanisms ; kinematic analysis ; parasites ; protoplasm flow ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spores of the microsporidium Nosema algerae were stimulated to germinate in vitro while observed with video-enhanced contrast microscopy. Field-by-field playback of tape-recorded sequences yielded the first serial illustrations and kinematic analysis of the explosive discharge of the polar filament and the sporoplasm. The filament emerges from the anterior pole of the spore in a regularly pitched helicoidal course along a nearly straight axis, with a mean maximum instant velocity of 105 μm/s. Just before elongation is completed the filament tip follows a tortuous path that often results in a curved or spiralling terminal configuration. Then elongation stops and, after a lag that may vary from less than 15 to over 500 ms, the sporoplasm pours out at the filament tip forming a globule that quickly grows up to a size larger than its original volume within the spore. Concomitantly, the helical filament becomes straightened and frequently the spore body is pulled forward. Thereafter a relaxed filament, usually 5-10% shorter than when maximally extended, remains connecting the empty spore case and the sporoplasmic droplet. Experiments with hyperosmolar media produced a considerable slowdown of filament extrusion and often precluded sporoplasm discharge. The present results are fully consistent with the hypothesis of a hydrostatic pressure-triggered mechanism of spore germination, and revealed that the process is composed of two discrete phases separated by a variable lag: (1) complete eversion of the polar filament, and (2) passage of the main sporoplasm mass along the tube. The data provide a preliminary basis toward the conception of a quantitative physical model of microsporidian spore germination. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970220105
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  • 166
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992) 
    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.970220201
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    Chromosome mal-orientation and reorientation during mitosis (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 155-159 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220302
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  • 168
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    Colchicine-sensitive and colchicine-insensitive intermediate filament systems distinguished by a new intermediate filament-associated protein, IFAP-70/280kD (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 185-199 
    Details
    ISSN: 0886-1544
    Keywords: BHK-21 cells ; cytoskeleton ; microfilaments ; microtubules ; stress fibers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A monoclonal antibody was produced, using as antigen a BHK-21 cytoskeletal preparation enriched in intermediate filaments (IF) and their associated proteins. This antibody reacted exclusively with a reproducible set of 70-280kD polypeptides present in minor quantities in this preparation, as detected by immunoblot analysis. Based upon several criteria, this immunologically related group of polypeptides was designated as IFAP-70/280kD (IF-Associated Protein): (1) it coisolated with IF in vitro, (2) it co-localized (by both immunofluorescence and immunoelectron microscopy) with IF in situ in all stages of cell spreading, and (3) it segregated in vitro with the 54/55kD (desmin/vimentin) structural IF subunit proteins of BHK cells through two cycles of in vitro disassembly/assembly. Immunogold labeling further localized IFAP-70/280kD to regions of parallel or loosely bundled IF in situ, suggesting a role in regulating the supramolecular organization of IF. When this monoclonal antibody was used for double-label immunofluorescence observations of colchicine-treated BHK cells, it demonstrated the presence of colchicine-sensitive and colchicine-insensitive IF. Anti-IFAP-70/280kD localized entirely to the drug-induced juxtanuclear IF cap, while a polyclonal antibody directed against the desmin/vimentin structural IF subunits and the previously characterized monoclonal anti-IFAP-300kD [Yang et al., 1985; J. Cell Biol. 100:620] localized to both the juxtanuclear IF cap and a colchicine-insensitive IF network peripheral to the cap in the same cells. The colchicine-insensitive IF pattern often exhibited similarities to that observed for the actin-based stress fiber system, suggesting that stress fiber association may be an additional factor in IF organization. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220306
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    Evidence for a gelsolin-rich, labile F-actin pool in human polymorphonuclear leukocytes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 25-37 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; human neutrophils ; actin binding proteins ; cytochalasins ; ultracentrifugation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Filamentous (F) actin is a major cytoskeletal element in polymorphonuclear leukocytes (PMNs) and other non-muscle cells. Exposure of PMNs to agonists causes polymerization of monomeric (G) actin to F-actin and activates motile responses. In vitro, all purified F-actin is identical. However, in vivo, the presence of multiple, diverse actin regulatory and binding proteins suggests that all F-actin within cells may not be identical. Typically, F-actin in cells is measured by either NBDphallacidin binding or as cytoskeletal associated actin in Triton-extracted cells. To determine whether the two measures of F-actin in PMNs, NBDphallacidin binding and cytoskeletal associated actin, are equivalent, a qualitative and quantitative comparison of the F-actin in basal, non-adherent endo-toxin-free PMNs measured by both techniques was performed. F-actin as NBD-phallacidin binding and cytoskeletal associated actin was measured in cells fixed with formaldehyde prior to cell lysis and fluorescent staining (PreFix), or in cells lysed with Triton prior to fixation (PostFix). By both techniques, F-actin in PreFix cells is higher than in PostFix cells (54.25 ± 3.77 vs. 23.5 ± 3.7 measured as mean fluorescent channel by NBDphallacidin binding and 70.3 ± 3.5% vs. 47.2 ± 3.6% of total cellular actin measured as cytoskeletal associated actin). These results show that in PMNs, Triton exposure releases a labile F-actin pool from basal cells while a stable F-actin pool is resistant to Triton exposure. Further characterizations of the distinct labile and stable F-actin pools utilizing NBDphallacidin binding, ultracentrifugation, and electron microscopy demonstrate the actin released with the labile pool is lost as filament. The subcellular localization of F-actin in the two pools is documented by fluorescent microscopy, while the distribution of the actin regulatory protein gelsolin is characterized by immunoblots with antigelsolin. Our studies show that at least two distinct F-actin pools coexist in endotoxin-free, basal PMNs in suspension: (1) a stable F-actin pool which is a minority of total cellular F-actin, Triton insoluble, resistant to depolymerization at 4°C, gelsolin-poor, and localized to submembranous areas of the cell; and (2) a labile F-actin pool which is the majority of total cellular F-actin, Triton soluble, depolymerizes at 4°C, is gelsolin-rich, and distributed diffusely throughout the cell. The results suggest that the two pools may subserve unique cytoskeletal functions within PMNs, and should be carefully considered in efforts to elucidate the mechanisms which regulate actin polymerization and depolymerization in non-muscle cells.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210104
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    Increased calmodulin affects cell morphology and mRNA levels of cytoskeletal protein genes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 45-57 
    Details
    ISSN: 0886-1544
    Keywords: cell shape ; gene expression ; pleiotropic effects ; cell cycle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously described stable mouse C127 cell lines in which a CaM mini-gene has been expressed in a bovine papilloma virus-based expression vector (Rasmussen and Means: EMBO J. 6:3961-3968. 1987). Elevation of CaM to levels five-fold higher than in control cells caused an acceleration in cell cycle progression by reducing the length of the G1 period. When these cell lines were originally isolated it was observed that cells in which CaM levels were increased had a flattened morphology. In this study we have examined the localization of actin, vimentin, and tubulin in these cells as compared to the BPV-transformed control cell line in order to determine if changes in shape were accompanied by differences in the cytoskeletal organization. Cell-cycle-dependent changes in the levels of mRNAs for histone H4, glyceraldehyde-3-phosphate dehydrogenase, β-actin, vimentin, and β-tubulin have also been examined. Our results indicate that increased CaM causes differences in the organization of microfilaments, intermediate filaments, and microtubules and that these changes are accompanied by selective differences in the cell-cycle-dependent expression of some mRNAs. Elevated CaM was also correlated with a reduced stability of β-tubulin mRNA. These studies indicate that CaM has pleiotropic effects on cell function and suggest that stable cell lines with altered CaM levels may provide a useful model system for understanding the moiecular basis of CaM-dependent regulation of cellular processes.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210106
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992) 
    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.970210201
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  • 172
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    Modulation of growth cone morphology by substrate-bound adhesion molecules (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 65-73 
    Details
    ISSN: 0886-1544
    Keywords: N-cadherin ; L1 ; laminin ; neurite outgrowth ; neuronal guidance ; filopodia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth cone, a terminal structure on developing and regenerating axons, is specialized for motility and guidance functions. In vivo the growth cone responds to environmental cues to guide the axon to its appropriate target. These cues are thought to be responsible for position-specific morphological changes in the growth cone, but the molecules that control growth cone behavior are poorly characterized. We used scanning electron microscopy to analyze the morphology of retinal ganglion cell growth cones in vitro on different adhesion molecules that axons normally encounter in vivo. L1/8D9, N-cadherin, and laminin each induced distinctive morphological characteristics in growth cones. Growth cones elaborated lamellipodial structures in response to the cell adhesion molecules L1/8D9 and N-cadherin, whereas laminin supported filopodial growth cones with small veils. On L1/8D9, the growth cones were larger and produced more filopodia. Filopodial associations between adjacent growth cones and neurites were frequent on L1/8D9 but were uncommon on laminin or N-cadherin. These results demonstrate that different adhesion molecules have profoundly different effects on growth cone morphology. This is consistent with previous reports suggesting that changes in growth cone morphology in vivo occur in response to changes in substrate composition.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210108
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992) 
    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.970220301
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  • 174
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    Control of organelle transport in melanophores: Regulation of CA2+ and cAMP levels (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 175-184 
    Details
    ISSN: 0886-1544
    Keywords: protein phosphorylation ; signal transduction ; motility ; alpha-adrenoceptors ; microtubules ; pigment ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Melanophores of the cichlid Tilapia mossambica can be induced to aggregate pigment by addition of epinephrine to the medium, suggesting adrenergic control of this transport. The melanophore response to adrenergic stimulation was examined using agonists and antagonists that are highly specific for each alpha-adrenoceptor subclass. The signal transduction mechanism of each subclass is unique: stimulation of alpha1 receptors results in a rise in intracellular free Ca2+, while alpha2 stimulation results in decreased cAMP levels [Exton, 1985: Am. J. Physiol. 248:E633-E647 ]. Each alpha1 or alpha2 specific agonist tested showed a dose dependent ability to induce aggregation and each was able to effect complete aggregation of pigment, suggesting that aggregation can be mediated either by elevating Ca2+ or by lowering cAMP. However, in the presence of either an alpha1 or an alpha2 receptor antagonist, none of the agonists were able to induce significant aggregation, suggesting that changes in levels of both messengers are required for pigment aggregation in the melanophores. Moreover, experiments in which intracellular levels of Ca2+ or cAMP were perturbed, using BAPTA and forskolin, respectively, indicated that elevating Ca2+ in the presence of high cAMP is not sufficient to induce aggregation and, conversely, that lowering cAMP levels in the presence of reduced Ca2+ is not sufficient to induce pigment aggregation. These data indicate that the concentrations of both cAMP and Ca2+ are important in regulating pigment aggregation in teleost melanophores, and suggest that maximal aggregation of pigment requires altering the levels of both messengers. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220305
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  • 175
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    Cytoskeleton of liver perisinusoidal cells (lipocytes) in normal and pathological conditions (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 227-234 
    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.970220402
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  • 176
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    Association of the β isoform of protein kinase C with vimentin filaments (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 250-256 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeletal localization ; signal transduction ; intermediate filaments ; rat basophilic leukemia cells ; translocation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Protein kinase C (PKC) isoforms are key mediators in hormone, growth factor, and neurotransmitter triggered pathways of cell activation (Nishizuka: Science 233:305-312, 1986; Nature 334:661-665, 1988). Stimulation of kinase activity by diacylglycerol and calcium often leads to translocation of PKC from the cytosol to a particulate fraction (Kraft and Anderson: Nature 301:621-623, 1983). The β isoform of PKC is translocated and degraded much more rapidly than the β isoform in phorbolester-stimulated rat basophilic leukemia (RBL) cells (Huang et al.: J. Biol. Chem. 264:4238-4243, 1989). We report here immunofluorescence evidence that the distributions of PKC α and β are strikingly different in antigen-activated RBL cells. PKC β associates with perinuclear filaments and filaments that extend from the perinuclear area to the cell periphery whereas PKC β concentrates in regions of the cell periphery. This distribution of PKC β is distinctly different from that of actin filaments and microtubules as determined by phalloidin staining and by anti-tubulin antibody labeling. In contrast, the staining patterns obtained with antibodies to PKC β and to the intermediate filament protein vimentin are almost identical, indicating that PKC β associates with vimentin filaments. These bundles of 100 Å filaments may provide docking sites for interactions of PKC β with its substrates and thus confer specificity to the actions of this isoform. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220405
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  • 177
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    Evolution of the flagellar waveform of ram spermatozoa in relation to the degree of epididymal maturation (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 8-18 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; flagella ; motility ; epididymis ; maturation ; mammal ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Motility and flagellar movement of ram spermatozoa along the epididymis were analysed in vitro. From the caput to the cauda of the epididymis, the percentage of motile and progressive spermatozoa increases. No flagellar bending was observed in spermatozoa from the testis or the epididymal anterior caput. When spermatozoa reached the distal caput of the epididymis, a static curvature, associated with an initiation of the flagellar beating, appeared on the flagella. This curvature normally disappeared during epididymal transit. Its disappearance was associated with an increase in the flagellar beat efficiency. Our results suggest that the initiation of motility is related to two mechanisms involving: (1) the presence of a transient static curvature, and (2) the establishment of a symmetric regular beating of the flagellum. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230103
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  • 178
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    Announcements (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 83-84 
    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.970230109
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  • 179
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992) 
    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.970230201
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  • 180
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    A high molecular weight centrosomal protein of mammalian cells is antigenically related to myosin II (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 122-132 
    Details
    ISSN: 0886-1544
    Keywords: centrosome ; microtubule ; microfilament ; myogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Available data on the molecular composition of the centrosome, the typical microtubule-organizing center of animal cells, are still fragmentary. To address this important issue we have taken advantage of centrosome isolation from a human lymphoblastic cell line (KE37) to generate a monoclonal antibody (mAb) library. Here we present the characterization of one of these mAbs (CTR56). On the basis of both its immunofluorescence staining pattern and its reactivity with a major 200 kD antigen on immunoblots, CTR56 has been tentatively classified as an anticellular myosin heavy chain. In light of cytological and biochemical data obtained in parallel with two other well-characterized myosin antibodies, it appears that myosin cannot be considered as a genuine centrosomal protein. We have resolved the paradoxical results with CTR56 by showing that in addition to the cellular myosin heavy chain, this antibody also recognizes a high molecular weight protein specifically enriched in centrosomal fractions. The possible biological significance of this finding is discussed in structural and functional terms. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230205
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  • 181
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    A shell of F-actin surrounds the branched nuclei of silk gland cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 169-187 
    Details
    ISSN: 0886-1544
    Keywords: nuclear actin ; nuclear myosin ; nuclear shell ; nuclear shape ; nuclear matrix ; silk gland ; nuclear structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The branched nuclei from silk gland cells of larvae of Calpodes ethlius label with antibodies to actin and myosin and with rhodaminyl-phalloin, which is specific for f-actin. Optical sectioning localizes this actin and myosin to the nuclear periphery. Residual nuclear-associated fractions prepared from these cells contain sheets of nuclear lamina-like structures that bind heavy meromyosin and gold-tagged antibodies to actin and myosin. The results suggest that both actin and myosin, or a myosin-like protein, are components of a layer at the nucleocytoplasmic boundary that we call the nuclear shell. The nuclear shell appears to be associated with the nuclear envelope and may correspond to a zone on the cytoplasmic face of the envelope seen in electron micrographs of unextracted cells. The residual nuclear-associated fraction has a unique isoform of actin (43 kD, pl 6.45) that might allow the nuclei to associate with an actin network structurally and developmentally distinct from that of the cytoplasm. © 1992 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230302
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  • 182
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    Ca2+-Regulated actin and phospholipid binding protein (68kD-protein) from bovine liver: Identification as a homologue for annexin VI and intracellular localization (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 200-210 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; liposome ; focal contact ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An F-actin binding protein was purified from bovine liver by means of DNase I affinity, hydroxylapatite and DEAE-cellulose column chromatographies. It consisted of a single polypeptide chain having an apparent molecular weight of 68,000 with a Stokes radius of 35Å. Electron microscopy of rotary shadowed specimens showed that the 68kD protein is a globular protein. This protein showed a higher affinity for F-actin in the presence of Ca2+ than in its absence, which is opposite to the actin-binding property shown by nonmuscle alpha-actinin or fimbrin. The 68kD protein had no F-actin severing and capping activity. Interestingly, the 68kD protein was found to aggregate liposomes at micromolar Ca2+ concentrations. Immunoblot analysis and partial protein sequence data identified the 68kD protein as an annexin VI (p68) homologue. Immunocytochemical studies showed that the 68kD protein was localized along stress fibers as well as membrane ruffles, microspikes and focal contacts, raising the possibility that annexin VI may contribute to control membrane-microfilament interaction in the cell. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220307
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  • 183
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    Phalloidin binds and stabilizes pea root actin (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 245-249 
    Details
    ISSN: 0886-1544
    Keywords: rhodamine phalloidin ; anti-chicken actin antibody ; plant actin ; DNase I ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous reports about phalloidin binding to plant actins have been indirect. We present here evidence showing that phalloidin does bind and stabilize filaments of actin extracted from pea roots. Criteria for the presence of actin included stabilization as a polymer in the presence of phalloidin, cross-reaction with antibody against chicken actin, affinity binding to DNase I, and ability to be decorated by the S1 fragment of rabbit muscle myosin.Phalloidin was able to stabilize polymers in pea root extracts against dissociation during SDS gel electrophoresis, and these polymers were shown to be composed exclusively of actin. Pea root actin isolated by affinity chromatography on a DNase I column was incubated with rhodamine phalloidin and electrophoresed on a native gel. The rhodamine fluorescence remained with the stabilized filaments, indicating clearly that phalloidin does bind to actin from a plant source. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220404
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  • 184
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992) 
    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.970230101
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  • 185
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    An immunofluorescence study of the effects of ultraviolet radiation on the organization of microfilaments, keratin intermediate filaments, and microtubules in human keratinocytes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 296-306 
    Details
    ISSN: 0886-1544
    Keywords: epidermal keratinocytes ; cytoskeleton ; UV induced reorganization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Indirect immunofluorescence microscopy has been used to investigate the ultraviolet (UV) radiation induced disruption of the organization of microfilaments, keratin intermediate filaments, and microtubules in cultured human epidermal keratinocytes. Following irradiation, concurrent changes in the organization of the three major cytoskeletal components were observed in cells incubated under low Ca2+ (0.15 mM) conditions. UV irradiation induced a dose-dependent condensation of keratin filaments into the perinuclear region. This collapse of the keratin network was accompanied by the reorganization of microfilaments into rings and a restricted distribution of microtubules, responses normally elicited by exposure to high Ca2+ (1.05 mM) medium. The UV induced alteration of the keratin network appears to disrupt the interactions between keratin and actin, permitting the reorganization of actin filaments in the absence of Ca2+ stimulation.In addition to the perinuclear condensation of keratin filaments, UV irradiation inhibits the Ca2+ induced formation of keratin alignments at the membrane of apposed cells if UV treatment precedes exposure to high Ca2+ medium. Incubation of keratinocytes in high Ca2+ medium for 24 hours prior to irradiation results in the stabilization of membrane associated keratin alignments and a reduced susceptibility of cytoplasmic keratin filaments to UV induced disruption. Unlike results from investigations with isogenic skin fibroblasts, no UV induced disassembly of microtubules was discernible in irradiated human keratinocytes. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220409
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  • 186
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    Distribution of detyrosinated microtubules in motile NRK fibroblasts is rapidly altered upon cell-cell contact: Implications for contact inhibition of locomotion (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 45-60 
    Details
    ISSN: 0886-1544
    Keywords: cell motility ; cytoskeleton ; microtubule dynamics ; wound healing ; leading edge ; ruffling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fibroblasts migrating into an experimental wound contain an extensive array of detyrosinated microtubules (Glu MTs) oriented in the direction of migration, whereas nonmotile cells in the interior of a monolayer contain Glu MTs that are primarily coiled around the nucleus. To determine the role of cell-cell contact in the formation of these distinct arrays of Glu MTs, we studied the distribution of Glu MTs by immunofluorescence in NRK fibroblasts that had been fixed at different intervals after they had established contact with other cells. Time-lapse video recordings were made of the contacting cells to provide a record of cellular behavior. In motile cells that became completely surrounded by virtue of contact with other cells, Glu MTs were found mostly coiled around the nucleus. The proportion of cells whose Glu MTs extended to the original leading edge decreased dramatically after the cells had been surrounded for 10 min or more. At earlier times, when the contact was confined to a portion of the cell margin, Glu MTs were absent from the area behind the contact site, yet were still oriented toward the noncontacting and ruffling margins. The contact-induced alteration of Glu MTs was not due to the cessation of forward locomotion of cells per se, since immobilization of cells with cytochalasin D did not cause a dramatic change in Glu MTs. That cell-cell contact also specifies the type of Glu MTs formed in cells was shown by experiments in which MTs were regrown following complete depolymerization with nocodazole. The remodeling of Glu MTs during cell-cell contact may be involved in cellular repolarization during contact inhibition of locomotion and will be a useful marker for further dissecting the molecular events of contact inhibition of motility. © 1992 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230106
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  • 187
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    Activation of maternal centrosomes in unfertilized sea urchin eggs (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 61-70 
    Details
    ISSN: 0886-1544
    Keywords: activation ; fertilization ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Centrosomes are undetectable in unfertilized sea urchin eggs, and normally the sperm introduces the cell's microtubule-organizing center (MTOC) at fertilization. However, artificial activation or parthenogenesis triggers microtubule assembly in the unfertilized egg, and this study explores the reappearance and behavior of the maternal centrosome. During activation with A23187 or ammonia, microtubules appear first at the cortex; centrosomal antigen is detected diffusely throughout the entire cytoplasm. Later, the centrosome becomes more distinct and organizes a radial microtubule shell, and eventually a compact centrosome at the egg center organizes a monaster. In these activated eggs, centrosomes undergo cycles of compaction and decompaction in synchrony with the chromatin, which also undergoes cycles of condensation and decondensation. Parthenogenetic activation with heavy water (50% D2O) or the microtubule-stabilizing drug taxol (10 μM) induces numerous centrosomal foci in the unfertilized sea urchin egg. Within 15 min after incubation in D2O, numerous fine centrosomal foci are detected, and they organize a connected network of numerous asters which fill the entire egg. Taxol induces over 100 centrosomal foci by 15 min after treatment, which organize a corresponding number of asters. The centrosomal material in either D2O- or taxol-treated eggs aggregates with time to form fewer but denser foci, resulting in fewer and larger asters. Fertilization of eggs pretreated with either D2O or taxol shows that the paternal centrosome is dominant over the maternal centrosome. The centrosomal material gradually becomes associated with the enlarged sperm aster. These experiments demonstrate that maternal centrosomal material is present in the unfertilized egg, likely as dispersed undetectable material, which can be activated without paternal contributions. At fertilization, paternal centrosomes become dominant over the maternal centrosomal material. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230107
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  • 188
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    240 kDa immunoanalogue of vertebrate α-spectrin occurs in Paramecium cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 111-121 
    Details
    ISSN: 0886-1544
    Keywords: anti-α-spectrin immunocytochemistry ; phalloidin staining ; cortex ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Polypeptide of 240 kDa immunorelated to vertebrate α-spectrin was detected in Paramecium cells. The antigen was identified by monospecific antibody directed against α-subunit of spectrin, which was isolated from chicken erythrocytes by affinity and anion-exchange chromatography. Immunoblotting tests demonstrated that the anti-α-spectrin cross reacted with the 240 kDa polypeptide of Paramecium as well as that of various vertebrate cells. In Paramecium, the antigen was detected in cytoskeletal fraction and in contractile extract of the cells. Immuno-fluorescent and immunoelectron microscopy observations revealed cortical localization of α-spectrin immunoanalogue in Paramecium. The label was distinctly seen on the whole surface of trichocyst tips. The antigen was also distributed close to the inner alveolar membrane forming a regular, continuous, lattice-like structure. When stained with rhodamine-phalloidin, Paramecium cells displayed a similar fluorescent network, which underlay contours of cortical units. Basal bodies of cilia were labeled with phalloidin as well. Detection of α-spectrin immunoanalogue in Paramecium cortex may provide a new insight into arrangement of cortical elements in this organism. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230204
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  • 189
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    Mechanics of the chloroplast rotation in Mougeotia: Measurement of angular velocity by laser diffractometry (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 102-110 
    Details
    ISSN: 0886-1544
    Keywords: Chloroplast movement ; phytochrome ; near infrared laser ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cell of the green alga Mougeotia orients its chloroplast by rotation, according to the direction or polarization of incident red light. The mechanics of the rotation is described by the angle of rotation and the angular velocity of the rotator (i.e., the chloroplast). We developed a laser diffractometer to determine the angle of rotation of the chloroplast. The angle of rotation of the chloroplast shifted by a constant angular velocity, and hence, the net torque on the chloroplast was zero. This suggests that the driving torque acting on the chloroplast is always balanced by the viscous torque. The maximal driving force acting on the chloroplast was estimated to be nearly equal to the force generated by an actomyosin system. This is the first measurement of the driving force acting on the chloroplast in Mougeotia. The amplitude of the force supported the anchorage site hypothesis. However, it remains unclear whether or not the angular independence of the force also supports the hypothesis. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230203
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  • 190
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    Cap100, a novel phosphatidylinositol 4,5- bisphosphate- regulated protein that caps actin filaments but does not nucleate actin assembly (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 133-144 
    Details
    ISSN: 0886-1544
    Keywords: actin polymerization ; Dictyostelium ; F-actin capping proteins ; phospholipids ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fast and transient polymerization of actin in nonmuscle cells after stimulation with chemoattractants requires strong nucleation activities but also components that inhibit this process in resting cells. In this paper, we describe the purification and characterization of a new actin-binding protein from Dictyostelium discoideum that exhibited strong F-actin capping activity but did not nucleate actin assembly independently of the Ca2+ concentration. These properties led at physiological salt conditions to an inhibition of actin polymerization at a molar ratio of capping protein to actin below 1:1,000. The protein is a monomer, with a molecular mass of ∼ 100 kDa, and is present in growing and in developing amoebae. Based on its F-actin capping function and its apparent molecular weight, we designated this monomeric protein cap 100. As shown by dilution-induced depolymerization and by elongation assays, cap100 capped the barbed ends of actin filaments and did not sever F-actin. In agreement with its capping activity, cap100 increased the critical concentration for actin polymerization. In excitation or emission scans of pyrene-labeled G-actin, the fluorescence was increased in the presence of cap100. This suggests a G-actin binding activity for cap100. The capping activity could be completely inhibited by phosphatidylinositol 4,5-bisphosphate (PIP2), and bound cap100 could be removed by PIP2. The inhibition by phosphatidylinositol and the Ca2+-independent down-regulation of spontaneous actin polymerization indicate that cap100 plays a role in balancing the G- and F-actin pools of a resting cell. In the cytoplasm, the equilibrium would be shifted towards G-actin, but, below the membrane where F-actin is required, this activity would be inhibited by PIP2. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970230206
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  • 191
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992) 
    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.970210101
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  • 192
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    Mechanical perturbation of webbed edges in 3T3 cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 15-24 
    Details
    ISSN: 0886-1544
    Keywords: actin edge-bundle ; cortical tension ; cell shape ; microfilaments ; cell adhesion ; cell motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously described actin edge-bundles (AEBs) as cables of microfil-aments lining the webbed edges of 3T3 cells (Zand and Albrecht-Buehler: Cell Motil. Cytoskeleton 13:195-211, 1989). We have suggested that AEBs, along with their cell-substratum adhesions, resist cortical tension and prevent the collapse of cytoplasm towards the nucleus. In this paper, we report several stages of AEB disassembly and re-formation induced by the following micro-manipulations(1)Scoring of the webbed edge of a 3T3 cells with a microneedle. As a result the sides of the score retracted and the severed AEB appeared to disassemble down to its terminal adhesion points. The retraction stopped after 20-40 seconds and the cells formed a webbed edge with large curvature. Over a period of 20-80 minutes, the new web decreased in length and depth, until it regained its approximate original shape.(2)Bending of cell processes at acute angles. As a result the processes moved until they projected at right angles to the side of the cell and formed new webs gradually expanded their area. In both cases, the nascent webs were lined by actin edge-bundles.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210103
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  • 193
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    Three-dimensional motility cycle in leukocytes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 211-223 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A 3-dimensional dynamic image analyzing system (3D-DIAS) has been developed in which a translocating cell is optically sectioned in the z-axis within a 2 sec period; the perimeter of the cell in each section is digitized into the 3D-DIAS data file, and the digitized perimeters are wrapped in order to reconstruct the cell image in three dimensions. Using 3D-DIAS, we have obtained the first dynamic 3-dimensional description of human polymorphonuclear leukocytes (PMN) translo-cating on a glass surface. A general behavior cycle has emerged which includes two phases. In the first, an ellipsoidal PMN with significant z-axis extends anteriorly and descends to the substratum. When the ventral surface of the anterior end contacts the substratum, there is rapid anterior expansion, which correlates with velocity peaks. In the second phase, the elongate PMN stops translocating along the substratum, the anterior end lifts off of the substratum, sometimes to heights greater than the length of the PMN at the substratum, and finally the PMN retracts into an ellipsoidal morphology still capable of random protrusions. During this second phase, which correlates with velocity troughs, turning usually occurs. The degree of turning is restricted by the continuous integrity of the posterior uropod. The period of the behavior cycle varies from roughly 0.5 to 2 min between PMNs, but is relatively constant within each individual PMN. © 1992 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220308
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  • 194
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    Spindle poles in higher plant mitosis (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 1-7 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230102
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  • 195
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    Intracellular cyclic AMP produces effects opposite to those of cyclic GMP and calcium on shape and motility of neuroblastoma cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 99-116 
    Details
    ISSN: 0886-1544
    Keywords: microinjection ; second messengers ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have directly evaluated the effects of various intracellular second messengers including cyclic nucleotides, calcium ion, and inositol polyphosphates on shape and motility of differentiating mouse neuroblastoma cells. The messengers were microinjected into cells and the responses of the soma, neurite, and growth cone were monitored using time-lapse video microscopy. Each messenger altered cell shape and motility in a characteristic manner. Cyclic AMP promoted lamellipodial expansion, neurite outgrowth, and motility. The other injected messengers opposed motility. Cyclic GMP caused motile structures to freeze and to retract permanently, while the inhibitory effects of calcium injection were concentrationdependent. Small calcium injections affected specifically actincontaining motile structures which froze and retracted temporarily. Intermediate calcium injections caused a strong contraction at the site of injection in all cells. With large injections, cells retracted long neurites, rounded up, and frequently began vigorous blebbing that continued to cell death. Injections of the inositol polyphosphates 1P3(1,4,5) and IP4(1,4,5,6) mimicked the effects of small calcium injections, as did electrical stimulation that elicited action potentials. The results suggest that in mouse neuroblastoma cells, intracellular CAMP elevation increases cytoskeletal organization and promotes neurite extension perhaps through an enhancement of cell-substratum adhesion. On the other hand, a rise of intracellular cGMP or intracellular calcium interferes directly with the function and organization of the actin-microfilament system. The integrated action of these second messenger systems may, therefore, operate in vivo to allow substances released from neighboring cells to regulate neuronal architecture. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220204
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  • 196
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    Actin dynamics during the cell cycle in Chlamydomonas reinhardtii (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 117-126 
    Details
    ISSN: 0886-1544
    Keywords: algae ; cell division ; cytokinesis ; mitosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used two monoclonal antibodies to demonstrate the presence and localization of actin in interphase and mitotic vegetative cells of the green alga Chlamydomonas reinhardtii. Commercially available monoclonal antibodies raised against smooth muscle actin (Lessard: Cell Motil. Cytoskeleton 10:349-362, 1988; Lin: Proc. Natl. Acad. Sci. USA 78:2335-2339, 1981) identify Chlamydomonasactin as a ∼43,000-Mr protein by Western immunoblot procedures. In an earlier study, Detmers and coworkers (Cell Motil. 5:415-430, 1985) first identified Chlamydomonas actin using NBD-phallacidin and an antibody raised against Dictyostelium actin; they demonstrated that F-actin is localized in the fertilization tubule of mating gametes. Here, we show by immunofluorescence that vegetative Chlamydomonas cells have an array of actin that surrounds the nucleus in interphase cells and undergoes dramatic reorganization during mitosis and cytokinesis. This includes the following: reorganization of actin to the ante- rior of the cell during preprophase; the formation of a cruciate actin band in prophase; reorganization to a single anterior actin band in metaphase; rearrange- ment forming a focus of actin anterior to the metaphase plate; reextension of the actin band in anaphase; presence of actin in the forming cleavage furrow during telophase and cytokinesis; and finally reestablishment of the interphase actin array. The studies presented here do not allow us to discriminate between G and F-actin. None the less, our observations, demonstrating dynamic reorganization of actin during the cell cycle, suggest a role for actin that may include the movement of basal bodies toward the spindle poles in mitosis and the formation of the cleavage furrow during cytokinesis. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970220205
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  • 197
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    The redeployment of F-actin in silk glands during moulting (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 101-110 
    Details
    ISSN: 0886-1544
    Keywords: F-actin ; silk gland ; phalloin ; periluminal circumferential actin bundles ; actin-coated vacuoles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Labeling of silk glands with rhodaminyl-phalloin shows that most F-actin is restricted to parallel bundles that form rings around the gland lumen at the apical cell surface. The bundles are lost when larval feeding stops at moulting, and the F-actin is redistributed through the cytoplasm as coats to vacuoles and, occasionally, in variably oriented strands. After moulting there is a return to the distribution of filamentous actin in the apical periluminal rings of bundles. These events occur at the same time as F-actin in the nuclear shell [Henderson and Locke, submitted] undergoes its own set of changes. In silk gland cells two kinds of f-actin deployment take place concurrently.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210203
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  • 198
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    An immunoreactive homolog of mammalian kinesin in Nicotiana tabacum pollen tubes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 132-137 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; vesicles ; cytoplasmic movement ; monoclonal antibody ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A cytoskeletal apparatus is involved in the movement of vesicles, organelles, and gametes in the pollen tube. The function of microfilaments has been defined quite precisely, but the role of microtubules needs to be further clarified. On the basis of immunological and biochemical investigations, we have identified a polypep-tide showing common properties with kinesin, a microtubule-based motor mainly described in nonplant tissues, in the pollen tube of Nicotiana tabacum. Like mammalian kinesin, the kinesin-immunoreactive homolog from Nicotiana tabacum pollen tubes binds to mammalian microtubules in an AMP-PNP dependent manner. The kinesin-like component is likely to be involved in the movement of vesicular material in the growing pollen tube.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210206
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  • 199
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    Cytoskeletal assembly and vinculin-cytoskeleton interaction in different phases of the activation of bovine platelets (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 123-131 
    Details
    ISSN: 0886-1544
    Keywords: thrombin ; cytochalasin B ; phorbol-myristate-acetate ; aggregation ; secretion ; contractile gel ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vinculin is an Mr 130 kDa protein that has been implicated in membrane-cytoskeleton interaction in various cell types. It has been demonstrated that vinculin is not a cytoskeletal component in resting platelets, but part of it becomes associated with the cytoskeleton during thrombin-induced activation. In this study, using a quantitative immunnoblotting technique, the relation of vinculin to the cytoskeleton in different phases of activation of bovine platelets was explored, and the process of incorporation of vinculin into the cytoskeleton was related to that of cytoskeletal assembly. The assembly of cytoskeleton proceeded at a significantly faster rate than the association of vinculin with it, which shows that the latter process is not due to passive trapping of vinculin into the Triton-insoluble residue, but certain biochemical changes had to occur before such an interaction became possible. When the formation of pseudopodia was prevented by cyto-chalasin B, but neither aggregation nor the release reaction induced by thrombin were inhibited, the recovery of vinculin in the Triton-insoluble residue even increased. In both time- and thrombin-concentration-dependent studies, poor correlation was found between vinculin-cytoskeleton association and the extent of aggregation. Activation with phorbol-myristate-acetate, which is a strong stimulus for aggregation but produces only a slight release in the granular content, resulted in the association of only a negligible amount of vinculin with the cytoskeletal fraction. The incorporation of vinculin into the cytoskeletal fraction of thrombin activated platelets started with the release reaction but still proceeded, and the greatest part of the reaction occurred after secretion had gone to completion. These findings suggest that platelet shape change and pseudopodium extrusion are not prerequisites for, and aggregation is not related to, vinculin-cytoskeleton interaction. The association of vinculin with the cytoskeleton correlates with the organization of contractile gel, which suggests a role for vinculin in secretion and clot retraction.
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    URL: http://dx.doi.org/10.1002/cm.970210205
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  • 200
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    Two distinct isoforms of sea urchin egg dynein (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 281-292 
    Details
    ISSN: 0886-1544
    Keywords: ATPase ; CTPase ; minus-end-directed microtubule motility ; cytoplasmic dynein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Extracts of unfertilized sea urchin eggs contain at least two isoforms of cytoplasmic dynein. One exhibits a weak affinity for microtubules and is primarily soluble. The other isoform, HMr-3, binds to microtubules in an ATP-sensitive manner, but is immunologically distinct from the soluble egg dynein (Porter et al.: Journal of Biological Chemistry 263:6759-6771, 1988). We have now further distinguished these egg dynein isoforms based on differences in NTPase activity. HMr-3 copurifies with NTPase activity, but it hydrolyzes CTP at 10 times the rate of ATP. The soluble egg dynein is similar to flagellar dynein in its nucleotide specificity; its MgCTPase activity is ca. 60% of its MgATPase activity. Non-ionic detergents and salt activate the MgATPase activities of both enzymes relative to their MgCTPase activities, but this effect is more pronounced for the soluble egg dynein than for HMr-3. Sucrose gradient-purified HMr-3 promotes an ATP-sensitive microtubule bundling, as seen with darkfield optics. We have also isolated a 20 S microtubule translocating activity by sucrose gradient fractionation of egg extracts, followed by microtubule affinity and ATP release. This 20 S fraction, which contains the HMr-3 isoform, induces a microtubule gliding activity that is distinct from kinesin. Our observations suggest that soluble dynein resembles axonemal dynein, but that HMr-3 is related to the dynein-like enzymes isolated from a variety of cell types and may represent the cytoplasmic dynein of sea urchin eggs.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970210404
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