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  • 1995-1999
  • 1990-1994  (2,230)
  • 1993  (2,230)
  • Life and Medical Sciences  (2,230)
  • Nuclear reactions
  • 1
    Electronic Resource
    Electronic Resource
    Variations in the distribution of motor end-plates in the avian pectoralis (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 65-88 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Most avian muscles consist of serially arranged, overlapping fibers that do not extend the length of the muscle. This condition appears to be plesiomorphic with respect to diapsid reptiles. The presence of this serialfibered architecture is evidenced by bands of stained motor end-plates (meps) perpendicular to the columns of fibers and dividing each column into a series of “segments.” The avian pectoralis was chosen for a study of variation in the distribution of meps within a single muscle. We report the interspecific variation for 158 specimens in 63 species. We also use additional specimens to examine intraspecific variation.Setting aside hummingbirds, which have an unique and clearly derived condition, the number of mep bands along a column of fibers near the shoulder falls within a remarkably small range. The number of segments is not obviously related to phylogenetic relatedness or to any characteristic of flight or ecology and is only slightly related to size. The largest specimens do average more segments per column, but there are no trends among small to medium-sized species, suggesting that there is an upper limit to fiber length. However, the shape of the sternum and pattern of connective tissue in the pectoralis alleviate the need for additional fibers in many large birds. These findings suggest that the architecture of the avian pectoralis is subject to some as yet unexplained selection that stabilizes the number of myofibers and/or motor neurons. The findings provide few clues as to whether the significant factors are phylogenetic, functional, ontogenetic, or some combination of these. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052150105
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  • 2
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    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.1052150201
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  • 3
    Electronic Resource
    Electronic Resource
    Morphological and functional bases of durophagy in the queen triggerfish, Balistes vetula (Pisces, tetraodontiformes) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 101-118 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tetraodontiform fishes are characterized by jaws specialized for powerful biting and a diet dominated by hard-shelled prey. Strong biting by the oral jaws is an unusual feature among teleosts. We present a functional morphological analysis of the feeding mechanism of a representative tetraodontiform, Balistes vetula. As is typical for the order, long, sharp, strong teeth are mounted on the short, robust jaw bones of B. vetula. The neurocranium and suspensorium are enlarged and strengthened to serve as sites of attachment for the greatly hypertrophied adductor mandibulae muscles. Electromyographic recordings made from 11 cranial muscles during feeding revealed four distinct behaviors in the feeding repertoire of B. vetula. Suction is used effectively to capture soft prey and is associated with a motor pattern similar to that reported for many other teleosts. However, when feeding on hard prey, B. vetula directly bit the prey, exhibiting a motor pattern very different from that of suction feeding. During buccal manipulation, repeated cycles of jaw opening and closing (biting) were coupled with rapid movement of the prey in and out of the mouth. Muscle activity during buccal manipulation was similar to that seen during bite-captures. A blowing behavior was periodically employed during prey handling, as prey were forcefully “spit out” from the mouth, either to reposition them or to separate unwanted material from flesh. The motor pattern used during blowing was distinct from similar behaviors described for other fishes, indicating that this behaviors may be unique to tetraodontiforms. Thus B. vetula combines primitive behaviors and motor patterns (suction feeding and buccal manipulation) with specialized morphology (strong teeth, robust jaws, and hypertrophied adductor muscles) and a novel behavior (blowing) to exploit armored prey such as sea urchins molluscs, and crabs. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052150202
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  • 4
    Electronic Resource
    Electronic Resource
    Early development of the chick embryo (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 165-182 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the early chick embryo was investigated, using scanning (SEM) and transmission electron microscopy (TEM). Eggs were obtained from the shell gland by injecting hens intravenously with a synthetic prostaglandin or arginine vasopressin. Embryos were examined during late cleavage (stages IV-VI, Eyal-Giladi and Kochav, '76), formation of the area pellucida (stages VII-XI), and formation of the hypoblast (stages X-XIV). SEM highlighted the reduction in cell number at the underside of the embryo during formation of the area pellucida although it became apparent that the thickness of the embryo is not reduced to a single layer of cells at stage X. In addition, blastomeres at the perimeter of embryos (stages V-VI) project filopodial extensions onto a smooth membrane that separates the sub-embryonic cavity from the yolk. During hypoblast formation, epiblast cells generate stellate projections at their basal aspect, thus providing a meshwork for the advancing secondary hypoblast cells. By stage XII the epiblast was one cell thick and reminiscent of a columnar epithelium when viewed transversely. Cells of the deep portion of the posterior marginal zone were distinguished morphologically in the stage XII embryo by their many cell surface projections and ruffled appearance. Blastomeres at the perimeter of stage V-VI embryos projected filopodial extensions onto a smooth membrane which separates the sub-embryonic cavity from the yolk. This membrane is presumed to be confluent with the cytolemma. Evidence is presented demonstrating the presence of intracellular membrane-bound droplets which are hypothesised to contain sub-embryonic fluid. © 1993 Wiley-Liss, Inc.
    Additional Material: 41 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052150205
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  • 5
    Electronic Resource
    Electronic Resource
    Land crabs with smooth lungs: Grapsidae, Gecarcinidae, and Sundathelphusidae ultrastructure and vasculature (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 245-260 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The highly terrestrial grapsids and gecarcinids and the amphibious sundathelphusids all have large, expanded branchial chambers. The lining of the branchial chambers is smooth and well vascularized, and it functions as a lung. The respiratory membrane and the cuticle lining the lung are extremely thin (200-350 nm). The blood vessels within the lung are formed from connective tissue cells supported by collagen fibres and lined by a basal lamina. The major vessels in the lung are embedded deep in the branchiostegite and lie just beneath the thick outer carapace. These vessels branch towards the respiratory membrane, where they eventually lose their connective tissue coverings to form thin, flattened lacunae directly below the respiratory epithelium. The lacunae (exchange sites) are bordered by specialized connective tissue cells, which either bear microvilli on their apical surface (fimbriated cells) or are very smooth. The respiratory circulation in the lung is very complex, with two portal systems present between the afferent and efferent systems, producing a total of three lacunal exchange beds. Portal systems increase the surface area available for gas exchange. The major distributing vessel in the lung is the branchiostegal vein, which runs along the inner margin of the branchiostegite. The main venous supplies come anteriorly from the infraorbital and ventral sinuses and posteriorly from the procardial sinus. The main collecting vessel is the pulmonary vein, which arises anteriorly and which runs around the ventral perimeter of the branchiostegite before emptying into the pericardial sinus. © 1993 Wiley-Liss, Inc.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052150306
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  • 6
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    Electronic Resource
    Naturally occurring diblastodermic eggs in the annual fish Cynolebias: Implications for developmental regulation and determination (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 301-312 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Annual fish development differs from that of other teleosts because a phase of blastomere dispersion-reaggregation spatially and temporally separates epiboly from embryogenesis. The fate of dispersed blastomeres was assessed in diblastodermic eggs of the annual fishes Cynolebias whitei and C. nigripinnis. In typical teleosts, blastomere determination and the events of primary embryonic induction occur prior to or during epiboly, so diblastodermic eggs produce partially or completely duplicated embryos. In the diblastodermic eggs of Cynolebias, the two blastoderms are completely separate from the one cell stage to the high blastula. Blastoderm fusion begins during midepiboly. By the end of epiboly, blastoderm fusion has been completed, and the deep, embryo-forming blastomeres of both blastoderms have completely dispersed and intermingled to form a single cell population. A typical annual fish dispersed blastomere phase ensues. Blastomeres reaggregate into a single mass, in which one embryo develops. When hatched, the young fish have no obvious structural or functional abnormalities. We suggest that the dispersed blastomeres of annual fish eggs are equivalent and that induction or determination takes place within the reaggregate. Alternatively, dispersed cells are partially determined but highly regulative, so that, when two populations fuse, the cells sort out according to tissue type and form a single embryo. In either instance, the formation of a single, normal embryo seems to corroborate the hypothesis that the dispersed cell phase of annual fishes is an adaptation that prevents environmentally induced developmental defects. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052150309
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  • 7
    Electronic Resource
    Electronic Resource
    Morphological analysis of tendinous structure in the American alligator jaw muscles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 171-181 
    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 American alligator, the jaw muscles show seven bundles of tendinous structure: cranial adductor tendon, mandibular adductor tendon, lamina anterior inferior, trap-shaped lamina lateralis, lamina intramandibularis, lamina posterior, and depressor mandibular tendon (originating from the musculus depressor mandibulae, m. pseudotemporalis, m. adductor mandibulae posterior, m. adductor mandibulae externus, m. intramandibularis, m. pterygoideus anterior, and m. pterygoideus posterior). These tendinous structures are composed of many collagen fibrils and elastic fibers; however, the distributions and sizes of the fibers in these tendinous components differ in comparison with those of other masticatory muscles. The differences of these properties reflect the kinetic forces or the stretch applied to each tendon by the muscle during jaw movements in spite of the simple tendon-muscle junctions. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052170206
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  • 8
    Electronic Resource
    Electronic Resource
    The horizontal septum: Mechanisms of force transfer in locomotion of scombrid fishes (Scombridae, Perciformes) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 183-204 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe the complex shapes of myomeres and myosepta in the mackerels and tunas (Scombridae: Teleostei), and we reveal the orientation of two major systems of collagen fibers in myosepta and horizontal septa with respect to points of attachment to skeleton and skin. Our goal is to identify the likely pathways of the transmission of muscle forces during locomotion. Our primary conclusions are (1) that the collagen fibers of myosepta, horizontal septa, and skin are the organs that transfer locomotor forces from the contraction of myomeres to the backbone and caudal fin during locomotion, and (2) that locomotor muscle pulls against a three-dimensional structure of tendons, septa, and skin that is kept in tension by the radial expansion of the contracting muscle. The main horizontal septum is formed by the convergence of myosepta and is likely to be the major transmitter of muscle force to the axial skeleton. The geometry of the myomeres, the position of red muscle, and particularly the geometric conformation of crossed-fiber arrays of collagen in the main horizontal septum suggest specific mechanisms for the transfer of muscle force to the backbone among scombrid fishes. Morphometrics and the construction of physical models help us to identify musculoskeletal mechanisms of locomotion, and we present two quantitative models of locomotor mechanics in fishes. © 1993 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052170207
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  • 9
    Electronic Resource
    Electronic Resource
    Oviductal morphology and eggshell formation in the lizard, Sceloporus woodi (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 205-217 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Despite a great deal of work in recent years on the structure of reptilian eggshells, few studies have examined the structure and regulation of the female reproductive tract in the formation of eggshell components, and none have examined the entire process from ovulation to oviposition. In this study, we examined oviductal structure in the oviparous lizard, Sceloporus woodi, followed changes in oviductal structure during gravidity, and determined uterine function in the formation of eggshell components. The endometrial glands of the uterus produce the proteinaceous fibers of the eggshell membrane mainly during the first 24 hours following ovulation, and the fibers are secreted intact and subsequently wrapped around the in utero eggs. Eggshell fibers of different thicknesses are layered around each egg, ranging from an inner layer of thick fibers that gradually become thinner medially and finally forms an outer layer of densely packed particulate matter. These changes in the fibrous layer are reflected by the thickness and length of fibers released from the endometrial glands. Calcium deposition occurs from 3 days following ovulation through day 14 (oviposition) and is accompanied by cellular changes in the luminal epithelium suggestive of secretory activity. Deposition of the eggshell components within the uterus occurs on all eggs simultaneously, rather than sequentially. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052170208
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  • 10
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    Electronic Resource
    Morphogenesis and ductal development of the prostatic complex of the guinea pig (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 219-227 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphogenesis of glandular architecture of the three lobes of prostate gland of the guinea pig, lateral, dorsal, and coagulating gland was studied from 35 days gestation to 90 postnatal days. Epithelial ductal tubules of various lobes of the gland were microdissected after treatment by collagenase and displayed two dimensionally. The number of ductal tips was counted, and the volume of the ductal network was quantified using a graphic tablet. The results show that the growth and ductal morphogenesis fall into two phases: prenatal and postnatal. The first outgrowth of prostatic buds begins at 35 days gestation (gestational length is 65 days). Ductal growth and branching continues over the next 15-20 days and by 55 days gestation, approximately 60%, 79%, and 71% of the adult number of ductal tips of the lateral and dorsal lobes and coagulating gland respectively, are formed. The figures increase to 89%, 84%, and 106%, respectively, by birth. There is little increase in number of ductal tips thereafter. Postnatal growth is accomplished mainly by elongation of existing ductal network with a little additional branching but with an increase in size (volume) of the tubules. Canalization of ductal tubules occurs prenatally in all lobes but postnatal functional cytodifferentiation takes a slightly different pace among them. Ductal morphogenesis of the guinea pig prostate gland differs significantly in time-course from that of the mouse in which ductal development occurs mainly postnatally. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052170209
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  • 11
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993) 
    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.1052170301
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  • 12
    Electronic Resource
    Electronic Resource
    Structure of comblike teeth of the ayu sweetfish, Plecoglossus altivelis (Teleostei: Isospondyli): I. Denticles and tooth attachment (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 229-238 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and tooth attachment of the comblike teeth and denticles of the ayu sweetfish, Plecoglossus altivelis, were examined by light and scanning electron microscopy. The denticle is composed of a spoonlike crown with a spine pointed anteriorly, a triangular plate in the cervical region, and a root that curves laterally and tapers off to a point. The root apex is fused with a long thin pedicle that turns abruptly anteriad toward the jaw bone. Planes of the spine, the spoonlike crown, the triangle plate and the root of the denticle are varied, and the denticle is twisted in the region of the triangle plane.The superficial layer of the dentine is homogeneously calcified and is considered to be enameloid, because some of the inner dentinal epithelial cells in the tooth germ are columnar and possess cellular processes at their apical ends. The dentine is fibrous and fine dentinal tubules are visible in dentine treated with sodium hydroxide and observed by scanning electron microscopy. The upper half of the root is surrounded by a dense layer of collagen fibers running parallel to the tooth axis, and the lower half is encompassed by interlaced collagen fibers. The lower part of the root is open on its lingual side. The pedicle is a long rod which is homogeneously calcified and enmeshed by interlaced collagen fibers, and it curves mediad as it nears the jaw bone. The pedicles are interposed between a layer of gelatinous connective tissue and the jaw bone and terminate on the periosteum. Comparative aspects of ayu tooth morphology are discussed. © 1993 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170210
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  • 13
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    Electronic Resource
    Effects of juvenile hormone analogues upon soldier differentiation in the termite Reticulitermes santonensis (Rhinotermitidae, Heterotermitinae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 239-261 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Under the influence of juvenile hormone analogues (JHAs), termite workers are induced to differentiate into soldiers. In Reticulitermes santonensis, such induced differentiation is often incomplete, resulting in intercaste production. The morphology of the structures most affected during differentiation was analyzed descriptively and biometrically in normal workers, presoldiers, and soldiers, and in experimental intercastes. We observed that intercastes form a morphological and biometrical continuum between workers and presoldiers (presoldier intercastes), and between presoldiers and soldiers (soldier intercastes). We also compared the biochemistry of the normal individuals and of the intercastes; in contrast to workers, the intercastes possess a frontal gland secretion which differs from those of the presoldiers and soldiers. Besides intercaste characterization, we consider the mode of action of JHAs in termite differentiation. © 1993 Wiley-Liss, Inc.
    Additional Material: 41 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170211
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  • 14
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    Electronic Resource
    Microtopography of Nippostrongylus brasiliensis (Nematoda: Heligmosomatidae): Free-living larval stages (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 263-271 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtopographic features of the various growth stages of the three free-living larval stages of the rat hookworm Nippostrongylus brasiliensis (Nematoda) were surveyed by scanning electron microscopy. These worms have a rounded anterior end and an elongated tail. Cuticular annulations were observed along the body, which also bore two ribbon-like lateral alae. Two rings of six lip-like lappets were observed around the triradiate oral opening in all larval stages. The cephalic space contained two lateral amphidial pits. The excretory pore in the third anterior part was observed in a ventral view of the larvae. No deirids were observed. The anus with a crescent-shape opening was located posteriorly. Phasmidial apertures, only observed in the third-stage larvae, opened on the lateral alae in the tail region. © 1993 Wiley-Liss, Inc.
    Additional Material: 28 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170302
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  • 15
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    Two different patterns of interrupted spermatogenesis in winter diapause and summer quiescence in the desert beetle, Omorgus freyi (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 347-358 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatogenesis discontinues during both adult reproductive diapause and quiescence in the flightless males of Omorgus freyi. During both types of dormancy, spermatogenesis discontinuity is a dynamic process involving an uninterrupted supply of primary spermatocytes that undergoes partial development and lyses before spermatozoa can be formed. Notwithstanding this common feature, the pattern of discontinuity differs between the two kinds of dormancy. During reproductive diapause, spermatozoa and late spermatids are the first cells that lyse; after diapause break, spermatozoa are produced anew. During quiescence, in contrast, the first indication of discontinuity is the degeneration of late primary spermatocytes; spermatozoa apparently remain intact for a while but eventually degenerate as well. Therefore, males returning to sexual activity after a short period of quiescence may still have spermatozoa capable of fertilization. However, following a long period of quiescence, spermatozoa will be absent and must be produced anew, as in postdiapausing males. The existence of two different patterns of spermatogenesis discontinuity may indicate that each is controlled differently by the endocrine system, in response to the different environmental conditions inducing quiescence or diapause. Dual control of discontinuity may contribute to the high reproductive potential of these flightless beetles, under unpredictable and extreme desert conditions. © 1993 Wiley-Liss, Inc.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180309
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  • 16
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    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    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.1052150101
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  • 17
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    Structure of recent and fossil mysid statoliths (Crustacea, Mysidacea) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 31-49 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Statoliths of 61 Recent species representing all subfamilies of Mysidae were studied with special emphasis on internal structure. In addition 5 samples of fossil statoliths from Miocene deposits were examined. Species of Boreomysinae and Rhopalophthalminae show simple roughly spherical organic statoliths, with setae originating from the sensory cushion and anchored in the statolith with distal branches extending shortly below the surface. All other subfamilies possess mineralized statoliths of greater structural complexity, with differentiation in core and mantle, where each part may consist of up to three layers. Habitus is hemispherical to discoidal. External gross structures are dorsal tegmen, ventral fundus, and the ambitus forming the outer toroidal to semi-toroidal circumference. Setae penetrate the mantle through mineralic canals and insert on the surface of the core. As suggested by congeneric species of Schistomysis, there is no principal structural difference between statoliths mineralized with fluorite compared to vaterite. However, vaterite statoliths tend to be more often of moruloid appearance and are exceptional by showing a central conical hole (the hilum) or a central cavity in certain forms. These structures are typical of fossil calcite statoliths. In vaterite and fluorite statoliths, the mantle shows radially arranged (= spherulitic) crystal aggregates. Such arrangements are badly preserved in fossil calcite statoliths. In large extant statoliths, concentric structures, mainly in the form of superficial striation and/or concentric microstrata, are visible in coexistence with radial aggregates. Stratification is possibly due to stratified deposition of the nonmineralized gland product, while the spherulitic structure is indicative of subsequent radial growth of crystal aggregates. The structure of accessory fluorite statoliths in the statocyst of Mesopodopsis slabberi leads to the hypothesis that mantle material is formed by secretions of the caudal statocyst gland. After demineralization of fluorite, vaterite and calcite statoliths, an organic template remains showing most essential morphological features of the statolith. From this we conclude that the structure of the statolith is (almost) entirely matrix mediated. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150103
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  • 18
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    Electronic Resource
    An ultrastructural study of the dorsal lingual epithelium of the crab-eating frog, Rana cancrivora (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 89-100 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The amphibian tongue contains two types of papilla which are believed to function in gustation and in the secretion of salivary fluid. Scanning electron microscopy reveals that columnar, filiform papillae are compactly distributed over nearly the entire dorsal surface of the tongue of the frog, Rana cancrivora, and fungiform papillae are scattered among the filiform papillae. Microridges and microvilli are distributed on the epithelial cell surface of the extensive area of the filiform papillae. Light microscopy shows that the apex of each filiform papilla is composed of stratified columnar and/or cuboidal epithelium and its base is composed of simple columnar epithelium. Transmission electron microscopy reveals that most of the epithelium of the filiform papillae is composed of cells that contain numerous round electron-dense granules 1-3 μm in diameter. Cellular interdigitation is well developed between adjacent cells. On the free-surface of epithelial cells, microridges or microvilli are frequently seen. Between these granular cells, a small number of ciliated cells, mitochondria-rich cells and electron-lucent cells are inserted. In some cases, electron-dense granules are present in the ciliated cells. At higher magnification, the electron-dense granules appear to be covered with patterns of spots and tubules. Overall, the morphology and ultrastructure of the lingual epithelium of the three species of Rana that have been studied are quite similar, but they can be easily distinguished from those of Bufo japonicus. Therefore, it appears that lingual morphology is phylogenetically constrained among members of the predominantly freshwater genus Rana to produce uniformity of papillary structure and this morphology persists in Rana cancrivora despite the distinct saline environment in which it lives. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    Pigment pattern formation in the larval salamander Ambystoma maculatum (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 151-163 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: As part of an ongoing comparative study of pigment patterns and their formation in embryos and larvae of ambystomatid salamanders, Ambystoma maculatum from two differnt populations, one in the northern (New York) and one in the central (Tennessee) United States, were investigated. Scanning electron microscopy was used to study early neural crest development. Light microscopy in combination with markers for the two pigment cell types (xanthophores and melanophores) made it possible to follow pigment cell migration before the pigment cells were fully differentiated. A bilateral pigment pattern consisting of two horizontal melanophore stripes surrounding an interstripe area populated by xanthophores formed in the larvae. In both populations, some variation was present in the form of a continuum ranging from clear horizontal stripes to extreme cases with a random pattern. Unlike the other ambystomatids that have been investigated, the neural crest cells in A. maculatum do not form aggregates and no vertical bars are formed. Instead, both the pattern and its formation are very similar to what has been reported for salamandrids. If pattern formation mechanisms can act as developmental constraints we would expect the A. maculatum pattern to be the primitive condition in the Ambystomatidae, using the Salamandridae as the outgroup. There is no strong support for this when aggregate formation is used as a character and mapped onto phylogenies for the group. The aggregate formation mechanism, and the pigment pattern that it leads to, have most likely been secondarily lost in A. maculatum. © 1993 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150204
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    A morphologic study of the ductus of the epididymis of Sus domesticus (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 183-193 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The head, body, and tail regions of the epididymal duct (or caput, corpus, and cauda epididymis) in two healthy and sexually mature Sus domesticus males were examined by light microscopy and by scanning or transmission electron microscopy. The epididymal duct is lined with a pseudostratified epithelium with stereocilia and covered by a muscular-connective tissue sheath that is thickest in the tail region. Diameter of the epididymal duct and height of epididymal epithelium are maximal in the head region. Length of the sterocilia and spermatic density are higher in the head and body regions. Somatic cells are abundant in the tail region. The epididymal epithelium is made up of five cell types: basal cells, principal cells, clear cells, narrow cells, and basophilic cells. Abundant secretory units are observed in the supranuclear cytoplasm of columnar principal cells. Each mature secretory unit is constituted by electron-dense secretion granules covered by more than eight layers of cisternae of reticulum between which the mitochondria are intercalated. In the apical cytoplasm the isolated secretion granules become larger and less electron dense. The apical surface is covered by numerous sterocilia. Basal cells are pyramidal and less high than principal cells. The clear cells, arranged between the principal cells, are characterized by the presence of abundant vesicular elements and electron-lucid secretion granules, and by an apocrine secretory process. The narrow cells are characterized by their highly vacuolized cytoplasm. Intermediate cell typologies can be found among basal, principal, clear, and narrow cells, which could be four developmental stages of the same cell type. The basophilic cells are spheroidal and are found at different levels between the epithelial cells and in the connective tissue underlying the epithelium. © 1993 Wiley-Liss, Inc.
    Additional Material: 39 Ill.
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    Testicular and androgen dependence of skin gland morphology in the anurans, Xenopus laevis and Rana pipiens (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 195-200 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In anuran amphibians, there is increasing evidence that exocrine glands dispersed throughout the general integument are secondary sex characters (SSC). Following the recent discovery of sexually dimorphic “breeding glands” in the dorsum of male Rana pipiens, we studied the effects of castration and testosterone treatment on the dorsal skin glands of male Xenopus laevis and R. pipiens to determine whether the dorsal breeding glands, or any other dorsal skin glands, are androgen dependent. The dorsal skin glands of X. laevis were unaffected by androgen status. By contrast, in R. pipiens, breeding, mucous, and seromucous glands responded to testosterone stimulation. Mucous glands were significantly (P 〈 0.05) larger in testosterone-treated frogs than in castrates. There was a large, but statistically insignificant, increase in the size of the dorsal breeding glands. Testosterone treatment also increased the epithelial cell height of breeding and seromucous glands (P 〈 0.05). In the skins of castrated and testosterone-treated frogs, there was a reciprocal relationship between the abundance of seromucous and breeding glands: in castrates, seromucous glands were abundant and breeding glands virtually absent, whereas in testosterone-treated frogs, breeding glands were abundant and seromucous glands less common. The total number of the two gland types was similar in both treatment groups. Glands that appeared to be intermediate in form between seromucous and breeding glands were observed in some frogs. These data suggest that seromucous glands may be the regressed form of breeding glands in the dorsal skin of R. pipiens and that the dorsal skin of R. pipiens is a SSC. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052150207
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  • 22
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    Development and fine structure of the bony scutes in Corydoras arcuatus (Siluriformes, callichthyidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 225-244 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and the structure of the bony scutes have been studied in a growth series of the armored catfish Corydoras arcuatus using light and electron microscopy. Fibroblast-like cell condensations appear in the dermis, in the posterior region of the caudal peduncle, and these will constitute the scute papillae. Collagen bundles of the preexisting dermis colonized by the papilla cells are remodeled and incorporated in the papilla to form, in addition to newly synthesized woven-fibered bony material, the initium of the scute. This process of formation differs from that described for the dermal papilla of an elasmoid scale. During growth, the osteoblasts surrounding the scute constitute the scute sac in which the scute grows. Parallel-fibered bone is deposited on both sides of the initium, and osteoblasts are incorporated within the scute matrix. The remodeling and incorporation of collagen bundles of the preexisting dermis is maintained during growth only in the deep, anterior region of the scute. The posterior region and the upper surface of the scute are close to the epidermal-dermal boundary. When growth slows down in the upper part of the scute, a characteristic, well-mineralized tissue, composed of thin vertical fibrils and granules and devoid of typical striated collagen fibrils, is deposited on the scute surface. A new term, hyaloine, is introduced for this nonosseous, highly mineralized layer constituting the upper part of the scute. Hyaloine shows thin electron-dense lines, which probably correspond to periodic growth arrests. The structure and localization of the hyaloine are compared to other well-mineralized, similar tissues found on the surface of the dermal skeleton in lower vertebrates. © 1993 Wiley-Liss, Inc.
    Additional Material: 35 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052150305
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993) 
    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.1052160101
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  • 24
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    Ultrastructural variations in the spermiogenesis of Triatoma infestans induced by temperature changes (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 17-27 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The reproductive process in insects may be affected by several factors, among which environmental temperature is one of the most important because of the poikilothermic condition of insects. To determine the effect of suboptimal temperature on the spermiogenic process of Triatoma infestans, males were exposed to 12°C for 10 days. In order to determine the reversibility of such alterations, males were returned to 28°C for 10 days after exposure to 12°C. Low temperature caused abnormal changes in the spermiogenic cells such as lack of spermatid orientation, general cyst disorganization, and asynchrony in the development of contiguous cysts. Highly vacuolized areas and pseudomyelinic bodies enclosing isolated or clustered vesicles of different electrodensity were also observed. At the end of the recovery time, cysts with spermatids developed synchronously. However, some presented isolated and clustered vesicles of different size and electrodensity. Some supernumerary organelles were also observed. These abnormal structures were related to processes of autophagy and phagocytosis of degenerating sexual cells. © 1993 Wiley-Liss, Inc.
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    Regionalization of eccrine and spermiophagic activity in spermathecae of the salamander Eurycea cirrigera (Amphibia: Plethodontidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 161-170 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermathecae of female Eurycea cirrigera are compound alveolar glands; narrow neck tubules connect the distal bulbs to a common tube that opens onto the roof of the cloaca. The common tube and neck tubules produce apical secretory vacuoles that contain a periodic acid-Schiff (PAS)+ substance for merocrine export into the lumen. This substance is produced throughout the year, although secretory vacuoles are less numerous during the period of reproductive inactivity in the summer. When sperm are present, the product from the secretory vacuoles bathes sperm in the lumen. Sperm are in orderly arrays and never are embedded in the cytoplasm of the common tube or neck tubules. The distal bulbs do not produce PAS+ secretory vacuoles, and are actively spermiophagic as long as sperm are present. Sperm become embedded in the epithelium of the distal bulbs where lysosomes degrade sperm. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170205
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  • 26
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993) 
    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.1052180301
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  • 27
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    Ultrastructural study of the ovary of the sessile scyphozoan, Haliclystus octoradiatus (Cnidaria: Stauromedusae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 225-236 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An ultrastructural study of the ovary of the sessible jellyfish, Haliclystus octoradiatus, indicates that it is fundamentally different from that of other scyphozoans and is the most structurally complex within the class. Oocytes develop within a series of spherical, sac-like ovarian follicles consisting of an enlarged intercellular space between two layers of subumbrellar gastrodermis. Developing oocytes are largely restricted to a thin germinal epithelium at the periphery of each follicle and gradually migrate toward the lumen as they mature. Individual oocytes are surrounded by early germ cells and follicle-like accessory cells of presumed somatic origin. Similar folliclelike cells have not been described in the Cnidaria previously. Vitellogenesis appears to involve the combined activity of the Golgi complex and associated rough endoplasmic reticulum. Ovarian morphology may be helpful in deciphering phylogeneitc relationships within the Cnidaria. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180210
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    Rostrate pedicellariae: A morphologically distinct form of echinoid test appendage (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 237-247 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The term rostrate was introduced by Mortensen ('07) to describe a type of pedicellaria he found in spatangoids. These pedicellariae resemble tridentate ones but have arching valves. Unlike the main categories of echinoid pedicellariae, no clear diagnosis of the rostrate form exists. This work examines the detailed morphology of the valves of rostrate pedicellariae observed by light and scanning electron microscopy and compares the shapes and dimensions of their component parts with tridentate pedicellariae. The data reveal considerable differences between the two, which warrant the recognition of rostrate pedicellariae as a distinct form. A diagnosis is given. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180302
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  • 29
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    Reproduction, placentation, and embryonic development of the Atlantic sharpnose shark, Rhizoprionodon terraenovae (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 257-280 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Atlantic sharpnose shark Rhizoprionodon terraenovae (Richardson) is a small carcharhinid that is a common year-round resident along the southeast coast of the United States. It is viviparous and its embryos develop an epithelio-vitelline placenta. Females enter shallow water to give birth in late May and early June. Mating occurs shortly after parturition, and four to seven eggs are ovulated. Fertilized eggs attain the blastoderm stage in early June to early July. Separate compartments for each egg are formed in the uterus when the embryos reach 3-30 mm. Embryos depend on yolk for the first 8 weeks of development. When embryos reach 72 mm their yolk supply is nearly depleted and they shift to matrotrophic nutrition. When the embryos reach 40-55 mm, placental development begins with the vascularization of the yolk sac where it contacts the uterine wall. Implantation occurs at an age of 8-10 weeks by which time the embryos reach 70-85 mm. The expanding yolk sac engulfs the maternal placental villi, and its surface interdigitates with the villi to form the placenta. The rest of the lumenal surface of the uterus is covered by non-placental villi that appear shortly after implantation. Histotrophe production by the non-placental villi begins just after their formation. The placenta grows continuously during gestation. The egg envelope is present throughout gestation, separating maternal and fetal tissues. Embryos develop numerous appendiculae on the umbilical cord. Young sharks are born at 290-320 mm after a gestation period of 11 to 12 months. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180304
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  • 30
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    The male reproductive system and mechanism of sperm transfer in Argulus japonicus (Crustacea: Branchiura) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 51-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The histomorphology of the male reproductive system and surface morphology of the “peg-and-socket” in Argulus japonicus are described from serial sagittal and transverse sections and scanning electron micrographs. The prostate complex consists of a glandular part, a reservoir for storing the secretion, and an efferent duct opening into the ejaculatory duct. The openings of both the vas deferens and the prostate duct into the ejaculatory duct are guarded by sphincters. The ejaculatory ducts, which are lined by tall columnar epithelial cells, do not open into the cuticle-lined genital atrium but are blind-ending tubes. This observation and results obtained from observing live specimens, as well as the fact that no spermatophores are formed, suggest that semen could leave the ejaculatory duct only after puncturing of its walls. It is suggested that sperm transfer is accomplished in the following manner: during copulation contraction of the muscular walls of the vas deferens and prostate duct causes semen to be pumped into the ejaculatory duct, which is then closed off by sphincters and a high internal pressure is developed. When a spermathecal spine penetrates the walls of the ejaculatory duct, semen flows from the ejaculatory duct into the spermathecal vesicle due to the higher pressure in the ejaculatory duct. This mechanism is analogous to the sucking up of fluid with a hypodermic syringe. © 1993 Wiley-Liss, Inc.
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    Anatomy of the larva of Amathia vidovici (Bryozoa: Ctenostomata) and phylogenetic significance of the vesiculariform larva (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 1-29 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Amathia vidovici (Vesiculariidae) has a lecithotrophic coronate larva. The apical disc of A. vidovici larvae is more complex than that of other vesiculariids and includes a new cell type, which may be glial-like in function. A massive nerve nodule consists only of neural processes; as no ganglia or other evidence of interneurons were found, sensory cells apparently innervate their effectors directly. Putative synaptic junctions within the nerve nodule indicate that both receptor and effector cells send processes to this neuropile. Some 44 intercoronal cells of three types, two of which are new, are interspersed among the approximately 40 coronal cells. Juxtapapillary bodies, a unique sensory complex previously known only from Bowerbankia gracilis larvae, also occur in A. vidovici. A large refractile body, which is of uncertain function and is positioned near the center of the larva, is described for the first time.A comparison of vesiculariid larvae that have been studied at the ultrastructural level reveals that larvae of Amathia vidovici and Bowerbankia gracilis are more similar to each other than either is to B. imbricata. Differences between the two Bowerbankia species, however, may reflect relative detail of their study and differences in interpretation rather than intergenic plasticity. Nevertheless. a distinctive suite of larval characteristics are shared by other members of the family Vesiculariidae, justifying a specific name - vesiculariform - for their larvae. A number of the defining characteristics of vesiculariform larvae also appear in the carnosan superfamily Victorelloidae. This finding is consistent with arguments based on adult characteristics that the Victorelloidea are ancestral to the Vesicularioidea. If this geneology is correct, one can predict that those vesiculariform traits which originated in the victorellids are plesiomorphic not only to the Family Vesiculariidae but to all sister taxa placed in the Vesicularioidea. © 1993 Wiley-Liss, Inc.
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    Cranial osteogenesis in Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 119-149 
    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 onset and general rate of cranial ossification are compared in two marsupials, Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae). In both species a similar suite of bones is present at birth, specifically those surrounding the oral cavity and the exoccipital, and in both postnatal events follow a similar course. The facial skeleton matures more rapidly than the neurocranium, which is characterized by an extended period of ossification. Most dermal bones begin ossification before most endochondral bones. Endochondral bones of the neurocranium are particularly extended in both the period of onset of ossification and the rate of ossification. These data confirm suggestions that morphology at birth is conservative in marsupials and we hypothesize that the pattern of cranial osteogenesis is related to two distinct demands. Bones that are accelerated in marsupials are correlated with a number of functional adaptations including head movements during migration, attachment to the teat, and suckling. However, the very slow osteogenesis of the neurocranium is probably correlated with the very extended period of neurogenesis. Marsupials appear to be derived relative to both monotreme and placental mammals in the precocious ossification of the bones surrounding the oral cavity, but share with monotremes an extended period of neurocranial osteogenesis. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052150203
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  • 33
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993) 
    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.1052150301
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    Falciparum malaria in naturally infected human patients: I. Ultrastructural differences between malaria pigments in intraerythrocytic asexual and sexual forms (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 201-206 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Venous blood samples were taken from patients naturally infected with the human malaria parasite Plasmodium falciparum. Two types of malaria pigment (MP) particles have been demonstrated in intraerythrocytic asexual forms (trophozoites and schizonts), while a single type was detected in gametocytes. Type I MP particles, found in both asexual and sexual forms, are electron-dense. It is suggested that these are proteinaceous and may be intermediate, utilizable metabolic products that serve as a food reserve during development of the parasite in the human host and also during the growth cycle of the sexual form in the mosquito. In asexual forms, type I particles occur within food vacuoles (FV) containing semidigested hemoglobin (Hg), while they are unenveloped in the cytoplasm of the sexual forms. Type II MP particles, found in electron-lucent residual bodies, are crystalloid and of low electron density. It is suggested that these are the final, waste product of Hg digestion in the asexual forms. © 1993 Wiley-Liss, Inc.
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    Falciparum malaria in naturally infected human patients: II. Ultrastructural alterations to erythrocytes infected with asexual forms (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 207-212 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructural alterations of human erythrocytes infected with asexual forms of Plasmodium falciparum were studied in naturally infected Saudi patients. These included surface knobs and nodules as well as invaginations associated with cytopasmic vesicles observed in erythrocytes infected with asexual forms of the parasites. Such nodules and surface invaginations have been previously described only in erythrocytes infected with P. ovale and P. vivax, respectively. Within the cytoplasm of infected erythrocytes were membrane-bound clefts, similar to those that appear to be a common characteristic in all red cells infected with malaria parasites. Vacuolations were often seen in the peripheral cytoplasm and may represent hemolyzed areas. Collapsed cells with an internal-lucent interior and surrounded by an irregularly folded membrane may represent completely hemolyzed erythrocytes. © 1993 Wiley-Liss, Inc.
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    A microscopic investigation of the lymphoid organs of the beluga, Delphinapterus leucas (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 261-287 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lymphoid organs from belugas, Delphinapterus leucas, ranging in age from less than one to 16 years, were harvested during a sanctioned hunt to investigate morphology. The spleen is divisible into red and white pulp and a stroma consisting of a reticular network, a collagenous capsule, and trabeculae containing smooth muscle bundles. White pulp areas appear to be devoid of follicles and consist mainly of periarteriolar lymphatic sheaths (PALS), that are larger in younger than in older belugas. Definitive marginal zones between red and white pulp are difficult to discern in older belugas. Lymph nodes are similar to those of other mammals; they possess a follicular cortex surrounding a vascular medulla composed of lymphatic cords and sinuses. Smooth muscle is abundant in the medullary region, usually in close proximity to sinuses. The expansive nodular mass at the root of the mesentery, often referred to as the “pseudopancreas,” is similar to lymph nodes in microscopic architecture. Pharyngeal tonsils and gut-associated lymphoid tissue (GALT) are found along the digestive tract and display an “active” morphology. Tonsils are comprised of lobules of follicles separated by vascular connective tissue. Epithelial-lined crypts communicate with the pharyngeal lumen. GALT consists of diffuse and follicular lymphocytes within the intestinal mucosa and submucosa. The thymus is well developed in the younger belugas, with lobules divisible into densely packed cortical zones of thymocytes and more loosely arranged medullary lymphocytes. Hassall's corpuscles are occasionally visible within the medulla. Cetaceans diverged evolutionarily from other mammals over 55 million years ago. This study investigates changes in lymphoid organ morphology in a species that now inhabits a unique ecological niche. This study also lays the groundwork for functional investigation of the beluga immune system, particularly as it relates to differences between healthy and stranded animals. © 1993 Wiley-Liss, Inc.
    Additional Material: 24 Ill.
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    Gliding flight in the American Kestrel (Falco sparverius): An electromyographic study (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 213-224 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographic (EMG) activity was studied in American Kestrels (Falco sparverius) gliding in a windtunnel tilted to 8 degrees below the horizontal. Muscle activity was observed in Mm. biceps brachii, triceps humeralis, supracoracoideus, and pectoralis, and was absent in M. deltoideus major and M. thoracobrachialis (region of M. pectoralis). These active muscles are believed to function in holding the wing protracted and extended during gliding flight. Quantification of the EMG signals showed a lower level of activity during gliding than during flapping flight, supporting the idea that gliding is a metabolically less expensive form of locomotion than flapping flight. Comparison with the pectoralis musculature of specialized gliding and soaring birds suggests that the deep layer of the pectoralis is indeed used during gliding flight and that the slow tonic fibers found in soaring birds such as vultures represents a specialization for endurant gliding. It is hypothesized that these slow fibers should be present in the wing muscles that these birds use for wing protraction and extension, in addition to the deep layer of the pectoralis. © 1993 Wiley-Liss, Inc.
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    Evolution and functional significance of tendon ossification in woodcreepers (Aves: Passeriformes: Dendrocolaptinae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 215 (1993), S. 289-300 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The woodcreepers, a clade of scansorial, neotropical birds, are distinctive among passerines in having extensive tendon ossification. Dissection of 42 of the 50 species indicates that such ossification in the hindlimb is limited almost entirely to tendons of insertion of the crural muscles. Most crural muscles have ossifications, and in all but one the ossified tendons are long and thin. Preliminary dissection revealed a similar pattern among ossified wing tendons. Phylogenetic analysis suggests that extensive tendon ossification is a synapomorphy of the woodcreepers. The species of Dendrocincla, which form a clade, show secondary reduction of ossification in some tendons, which may be correlated with increased intraspecific variation and with an expansion of foraging habits and postures to include nonscansorial behaviors. In contrast, the larger woodcreepers, other than Drymornis bridgesii and Nasica longirostris, form a clade with virtually no loss in ossification or evidence of intraspecific variation, even in large series of two species. Phylogenetic losses do not occur for the primary flexor of the ankle (M. tibialis cranialis), whereas two extensors (Mm. fibularis longus and gastrocnemius pars lateralis) show a complex pattern of derivation and loss. Previous biomechanical studies demonstrate that ossification increases the stiffness of tendons, making them stretch less under a given force. These structural and phylogenetic patterns are consistent with the view that hindlimb tendon ossification in woodcreepers is an adaptation to resist increased forces that act to extend the limb during vertical climbing. © 1993 Wiley-Liss, Inc.
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    Follicular dynamics and germinal bed activity during the annual ovarian cycle of the lizard, Calotes versicolor (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 1-7 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changes in size frequency distribution of extrastromal follicles, atretric follicles (AF), and the number of oogonia, oocytes, and primordial follicles in the ovaries are studied in Calotes versicolor during its annual reproductive cycle. Extrastromal follicles were graded into stages I to VI based on their diemeter. Stage I (0.5-0.75 mm) follicles are found throughout the year. The recruitment of stage II (0.76-1 mm) and stage III (1.10-2 mm) follicles occurs during December and March, respectively. Follicles of stage I-III are found in greater number in May. Stage IV vitellogenic follicles (2.10-3 mm) are recruited in April. Advanced vitellogenic follicles (stage VI) are formed between May and August. From April to August, the ovaries of lizards contain vitellogenic follicles of stages IV or V or VI suggesting that once a set of follicles enters vitellogenic phase there is no recruitment of another set of vitellogenic follicles from previtellogenic follicles until the former ovulates. The presence of vitellogenic follicles and at least two sets of CL in July-August suggest that C. versicolor may oviposit at least three clutches of eggs per season. The clutch size in this lizard varies from a maximum 24 eggs in May to a minimum of 13 eggs in September. The previtellogenic AF are found throughout the year. Atresia is more prevalent in stage III suggesting that these follicles are more prone to become atretic. Interestingly, atresia of vitellogenic follicles occurs rarely. Each ovary in C. versicolor has two germinal beds. The germinal beds contain a greater number of oogonia (536-696), primary oocytes (40-71), and primordial follicles (32-55) during prebreeding and early breeding phases of the ovarian cycle. © 1993 Wiley-Liss, Inc.
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    Ultrastructure of the spermatozoon of the teleost fish Acanthopagrus schlegeli (Perciformes: Sparidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 29-33 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructurally the spermatozoon of Acanthopagrus schlegeli (Sparidae) has a spherical, homogeneously electron-dense nucleus with a deep axial nuclear fossa, and an unusual notch, shaped like a bowtie, in the nuclear region. The short midpiece contains four spherical mitochondria and encircles the basal body of the flagellum. It is concluded that the spermatozoon is of a primitive type, although it is characterized by several unique features which may provide useful systematic characters. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    In-series fiber architecture in long human muscles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 35-45 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fiber architecture of adult human sartorius and gracilis muscles was examined using a combination of fiber microdissections and histological methods. Intact fibers were dissected from fascicles of muscle strips that were digested in nitric acid. All of these fibers terminate intrafascicularly by tapering to a fine strand at one or both ends. They measure 4-20 cm after correction for shrinkage. Systematic dissections of 1 cm long blocks sampled at intervals along the muscle length suggest that tapered fiber endings occur at all locations along the muscle but are most common centrally; here they accounted for up to 14% of dissected fibers in each block. Transverse sections of muscle confirm that fiber profiles with small diameters occur at all levels of the muscle but are especially common in sections more than 5 cm from its origin or insertion. The architectural arrangement demonstrated here suggests that long human muscles, like muscles in other species, are composed of relatively short, in-series fibers. This has many implications for the neural activation and force-developing behavior of these muscles that must be considered when paralyzed muscles are reanimated using electrical stimulation. Further, it may predispose long muscles to certain types of neuromuscular damage and dysfunction. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    Suboccipital muscles in the cat neck: Morphometry and histochemistry of the rectus capitis muscle complex (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 47-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphometry, histochemistry, and biomechanical relationships of rectus capitis muscles were examined in adult cats. This family of muscles contained six members on the dorsal, ventral, and lateral aspects of the upper cervical vertebral column. Three dorsal muscles (rectus capitis posterior major, medius, and minor) formed a layered complex spanning from C1 and C2 to the skull. Rectus capitis posterior major was composed predominantly of fast fibers, but the other two deeper muscles contained progressively higher proportions of slow fibers. One ventral muscle, rectus capitis anterior major, was architecturally complex. It originated from several cervical vertebrae and appeared to be divided into two different heads. In contrast, rectus capitis anterior minor and rectus capitis lateralis were short, parallel-fibered muscles spanning between the skull and C1. The ventral muscles all had nonuniform distributions of muscle-fiber types in which fast fibers predominated. Dorsal and ventral muscle groupings usually had cross-sectional areas of 0.5 cm2 or more, reflecting a potential capacity to generate maximal tetanic force in excess of 9 N. Biomechanical analyses suggested that one muscle, rectus capitis lateralis, had its largest moment in lateral flexion, whereas the other muscles had large, posturally dependent moment arms appropriate for actions in flexion-extension. The observation that most rectus muscles have relatively large cross-sectional areas and high fast-fiber proportions suggests that the muscles may have important phasic as well as postural roles during head movement. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    Organization of hematopoietic tissue in the intermolt lobster, Homarus americanus (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 65-78 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hematopoiesis in the American lobster Homarus americanus, as in most decapod crustaceans, occurs in a thin tissue covering the dorsal surface of the foregut. This tissue is composed of loosely attached, ovoid lobules containing the hematopoietic precursors and maturing hemocytes. Release of hemocytes into the dorsal hemocoel is accomplished by rupture of a portion of the connective tissue capsule covering the lobule. Cross sections of the lobules contain between 6 and 40 hematopoietic cells, of which approximately 90% constitute stages in granulocyte maturation and 10% are intermediates in hyaline cell maturation. Hematopoietic precursors in these two lines are similar to those recently described in a penaeid shrimp Sicyonia ingentis. The mitotic rate averaged 5.1% (range = 0.7% to 15.8%) in intermolt lobsters, 90% comprised granulocyte precursors. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    Structural characteristics of marsupial brood pouches of the antarctic sea urchins Abatus nimrodi and Abatus shackletoni (Echinoidea: Spatangoida) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 79-93 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Marsupial spines, tubercles, and pedicellariae of the antarctic brooding spatangoids Abatus nimrodi and Abatus shackletoni have been examined by scanning electron microscopy. Individual brood pouches of A. nimrodi may hold up to 28 embryos and juveniles and those of A. shackletoni may hold up to 38 lecithotrophic embryos and juveniles. Juveniles can be divided into (a) those with early development of external elements and a mean size of 2.0 and 1.6 mm, respectively, and (b) those equipped with fully developed external elements and a mean length of 4.3 and 2.8 mm, respectively. Mean diameters of aboral brood pouch openings of A. nimrodi and A. shackletoni were 6.5 and 4.1 mm, respectively. Brood pouches contain tall, distally enlarged spines, and smaller, layered cover-spines, which form a protective arch over the marsupia. There are also slender brood-pouch-bottom spines, which have an extremely thickened spinal epidermis. A. nimrodi has mainly bidentate, but also triand quadrodentate pedicellariae. A. shackletoni has two forms of tridentate, rostrate, and globiferous pedicellariae. In A. shackletoni, marsupial spine density is significantly lower than in A. nimrodi. These differences may be related to distinct sediment characteristics in their respective habitats. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    Announcement (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 113-113 
    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.1052160111
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993) 
    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.1052160201
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  • 47
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    Ultrastructure of prothoracic glands during larval-pupal development of the tobacco hornworm, Manduca sexta: A reappraisal (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 95-112 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of Manduca sexta prothoracic glands was investigated using a protocol that preserves membranes. During the last larval stadium, prothoracic gland cells increase in diameter, volume, protein content, and perhaps number, enhancing their capacity to produce ecdysteroids. The glands' strand-of-cells morphology, their in situ location, the presence of gap junctions between cells, and junctional foot-like structures within cells support previous findings that prothoracicotropic hormone stimulates ecdysteroidogenesis via Ca2+-induced Ca2+ release. A different method of tissue fixation from that previously used to investigate the ultrastructure of Manduca sexta prothoracic glands has revealed a significantly different ultrastructure. These new findings begin to define roles for endoplasmic reticulum and mitochondria in ecdysteroid synthesis and support the hypothesis that the glands secrete the steroid hormone via exocytosis. The structural dynamics of the glands are discussed in the context of the glands' function during Manduca sexta larvalpupal development. © 1993 Wiley-Liss, Inc.
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    Structure and histochemical organization of the spleen of Agama stellio (Sauria: Agamidae) and Chalcides ocellatus (Sauria: Scincidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 115-120 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spleen of Agama stellio is composed mainly of red pulp; the white pulp is poorly developed, and its clusters are scattered throughout the organ and contain lymphocytes, reticular cells, and some plasma cells. The red pulp consists of clear reticular cells intermingled with blood cells, sinusoids, and pigment cells. The spleen of Chalcides ocellatus is encapsulated by connective tissue and is composed of white and red pulp. The white pulp consists of lymphoid tissue that surrounds the central arterioles, forming the periarteriolar lymphocyte sheath (PALS). The red pulp is composed of a system of venous sinuses and cords. The results of various histochemical procedures designed to demonstrate mucosubstances, proteins, and nucleic acids indicate that the spleen in these species resembles the mammalian spleen. © 1993 Wiley-Liss, Inc.
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    Cleavage pattern in embryos of Haliotis tuberculata (Archaeogastropoda) and gastropod phylogeny (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 121-139 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The early cleavage pattern in embryos of the archaeogastropod Haliotis tuberculata strongly resembles the cleavage pattern of the archaeogastropods Trochus and Patella. It typically deviates from the cleavage patterns found in embryos of more advanced Archaeogastropoda, Caenogastropoda (the majority of the meso- and neogastropods), and Euthyneura (opisthobranch and pulmonate gastropods). It is assumed that the cleavage pattern found in Haliotis, Trochus, and Patella represents the ancestral pattern. A regular pattern of heterochronic changes in the succession of the formation of the larval trochoblasts and the stem cell of the adult mesoderm can be observed from the more primitive Archaeogastropoda to the more advanced Euthyneura. This observation strengthens the idea that the early cleavage pattern contains significant phyletic information. © 1993 Wiley-Liss, Inc.
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    On the structure of the aortic valves in snakes (Reptilia: Serpentes) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 141-159 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Aortic valve morphology was examined in 32 species of snakes representing 28 genera and 11 families and a diversity of habitat preferences. The results largely agree with previous studies but include some previously undescribed features, such as the cranial displacement of the cusps in the left aorta in some species and the structure of the opposing cusps of the interaortic foramen. Few features of the aortic valves are uniform among species. The pattern of morphological variation does not correlate with simple habitat preference (e.g., terrestrial, arboreal); however, some of the variation, particularly in the valves themselves, correlates with taxonomic relationships. We suggest that the presence of an interaortic foramen, with its associated valve, could result in an interaortic shunt of blood that potentially alters hemodynamics and flow patterns in the systemic circulation of snakes. © 1993 Wiley-Liss, Inc.
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    Microstructure, ontogeny, and evolution of scale surfaces in xenosaurid lizards (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 161-177 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Both scanning electron and light microscopy were used to examine the epidermal structure of scales taken from several ontogenetic stages of Xenosaurus grandis and Shinisaurus crocodilurus. In addition, scales from all xenosaurid species were examined by scanning electron microscopy to determine scale surface variation among genera, species, and subspecies. A varied and phylogenetically informative morphology characterizes the scale surfaces of xenosaurid lizards. Scale surface morphology is conservative among the species and subspecies of Xenosaurus, but is more variable between the two xenosaurid genera. Their scale surfaces are characterized by folds in the oberhautchen, beta, mesos, and alpha epidermal layers, forming polygonal ridges of a type previously described for the Iguania. The three species of Xenosaurus possess lenticular scale organs, whereas Shinisaurus has scale organs with spikes (bristles). The spikes of Shinisaurus are formed by the beta and oberhautchen layers, with the alpha layer forming a dome-shaped cap over a dermal papilla. Shinisaurus crocodilurus exhibits a dramatic ontogenetic change in scale surface morphology, that is here reported for the first time in any lizard. © 1993 Wiley-Liss, Inc.
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    Histology of the late-stage placentae in the matrotrophic skink Chalcides chalcides (Lacertilia; Scincidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 179-195 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Examination of late-stage placental material of the lizard Chalcides chalcides from the Hubrecht Laboratorium (Utrecht, The Netherlands) reveals several cytological and histological specializations that appear to have been superimposed over a morphological pattern that is typical for squamates. The chorioallantoic placenta is highly vascularized and consists of a single mesometrial placentome and a generalized paraplacentomal region, both of which are epitheliochorial. The placentome is deciduate, and contains deeply interdigitating folds of hypertrophied uterine and chorioallantoic tissue. Chorionic epithelium lining the placentome comprises enlarged, microvilliated cells, a small proportion of which are diplokaryocytes. The placentomal uterine epithelium is not syncytial and consists of enlarged cells bearing microvilli. The yolk sac placenta is a true omphaloplacenta (sensu stricto), being formed by juxtaposition of uterine tissues to an avascular, bilaminar omphalopleure. Epithelium of the omphalopleure is stratified and is hypertrophied into papillae that project into detritus of the uterine lumen. The omphalopleure is separated from the yolk sac proper by a yolk cleft that is not confluent with the exocoelom and is not invaded by the allantois. Neither an omphalallantoic placenta nor a true choriovitelline placenta is present in late gestation. Morphologically, the mature placentae of C. chalcides are among the most specialized to have been described in reptiles, reflecting the substantial maternal-fetal nutrient transfer that occurs in this species. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993) 
    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.1052160301
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    Chiropteran tendon locking mechanism (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 197-208 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rather than the usual mammalian scheme in which tendon and sheath surfaces provide as little friction as possible, the tendons and sheaths of many bats have a locking segment on the manual and pedal flexor tendon complex. This tendon locking mechanism (TLM) exists opposite the proximal phalanges of each toe and pollex of many bats. Its structure, similar to a ratchet mechanism, assists bats in hanging with little muscular effort. The third digit of the pelvic limb and the pollex of species representing 15 chiropteran families were studied to determine the presence or absence, morphology, and function of the TLM. Most of the species studied have a TLM consisting of a patch of tubercles on the ventral surface of the flexor tendon associated with the proximal phalanx of each pollex or toe. The sheath adjacent to this portion of the flexor tendon has a series of transverse folds or ridges, which, when engaged with the tubercles on the tendon, lock the tendon in place. The TLM is similar in megachiropterans and microchiropterans possessing it. The TLM is absent, however, in some of the microchiropterans studied, most notably in the phyllostomids. Since many birds have a TLM similar to that of bats, it is an excellent example of the convergent evolution of a feature brought about by similar functional pressures on birds and bats. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052160207
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    Development of the inner ear of the brown trout (Salmo trutta fario): I. Gross morphology and sensory cell proliferation (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 209-223 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross development of the trout inner ear between embryonic and juvenile stages was studied by light microscopy. The otocyst has already formed in 3-4 mm embryos. The semicircular canals begin to separate from the utriculo-saccular cavity in 6 mm embryos, the anterior canal first, then the posterior and the horizontal canal later. The formation of the saccular cavity begins in 7 mm embryos, whereas that of the lagena occurs in 18 mm fry. The first macular primordia appear before the separation of cavities. The anterior and horizontal crests arise from the primordium of the utricular macula, and the posterior crest, macula lagena, and macula neglecta arise from that of the saccular macula. The macula lagena and macula neglecta appear later. The sensory areas of the labyrinth and the number of receptor cells grow continuously between the embryonic and juvenile stages. © 1993 Wiley-Liss, Inc.
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    Early events in myofibrillogenesis and innervation of skeletal, sound-generating muscle in a teleost fish (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 225-239 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The plainfin midshipman, Porichthys notatus, generates acoustic communication signals through the rapid contraction of a pair of vocal (sonic) muscles attached to the walls of the swimbladder. Light and electron microscopic methods were used to study two aspects of sonic muscle ontogeny: (1) the development and transformation of myotubes into muscle fibers and (2) innervation, including the formation of sonic neuromuscular junctions and the myelination of sonic motor axons. Sonic motor axons are associated with sonic mesenchyme during its initial migration away from occipital somites. However, myofibrillogenesis, the formation of neuromuscular junctions, and axon myelination do not occur until sonic mesenchyme reaches its final destination (i.e., the swimbladder). A continuum of developing myotubes is present rather than two temporally distinct populations of primary and secondary myotubes as observed for skeletal muscles in mammalian and avian species. Potential reasons for the lack of primary and secondary myotubes are considered, including the functional homogeneity of the sonic motor system and the sonic muscle's unique architecture, namely its direct attachment to the wall of the swim-bladder. © 1993 Wiley-Liss, Inc.
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    Development of the inner ear of the brown trout (Salmo trutta fario): II. Cytodifferentiation and innervation of sensory cells (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 241-257 
    Details
    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 the sensory organs of the trout labyrinth by means of electron microscopy show that hair cells differentiate gradually in these organs; all of them produce new cells over a long period. The course of cytodifferentiation follows a similar pattern in all organs. Afferent nerve fibers and terminals are found at approximately the same time that sensory cells are being differentiated; the efferent synapses appear latter in development. The maturation of the both types of synapses is described. © 1993 Wiley-Liss, Inc.
    Additional Material: 40 Ill.
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    Ultrastructure and cytochemistry of secretory cells in the skin of the leech, Dina lineata (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 295-304 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure and histochemical features of the two types of secretory cells in leech skin are described. Pear-shaped cells secrete mucus containing carboxylated mucosubstances, while tubular cells produce a mucus containing a mixture of neutral, carboxylated, and sulfated mucosubstances. Pear-shaped secretory cells have two types of neuroglandular junctions, one containing dense-core serotonergic vesicles and the other small clear vesicles. Tubular secretory cells have large terminals, with many clear vesicles thought to be cholinergic. © 1993 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160305
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    Entry of nephrons into the collecting duct network of the avian kidney: A comparison of chickens and desert quail (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 259-269 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The avian kidney contains a population of nephrons with and without loops of Henle. How the collecting ducts of this heterogeneous population of nephrons merge to exit as single ducts from the medullary cones has been uncertain. The results of this study show that the collecting duct tree begins with the coalescence of the distal tubules of pairs of loopless nephrons. These primary collecting ducts receive output from only loopless nephrons. Primary collecting ducts fuse in pairs and become secondary collecting ducts. They receive the distal tubules of transition nephrons. Pairs of secondary collecting ducts fuse and become tertiary collecting ducts. Tertiary collecting ducts receive the distal tubules of looped nephrons. Thus, the fluid from all nephron types comingles as it passes through the medullary cone. The results of this study also show that the anatomical arrangement of medullary cones does not permit the output from one medullary cone to enter a second medullary cone. Thus, all the medullary cones function as parallel units. This anatomical organization of the avian kidney affects its ability to produce a urine hyperosmotic to the plasma. © 1993 Wiley-Liss, Inc.
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    Continuous and discontinuous growth in the otolith of Macruronus novaezelandiae (Merlucciidae: Teleostei) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 271-294 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Viewed by transmitted light, the lapillus and astericus otoliths Macruronus novaezelandiae (Merlucciidae) contain radial bands of similar width to the distances between steps on the surface of the otolith. The sagitta otolith has a multi-prismatic structure and shows differences in ultrastructure between its dorsal and ventral growth axes, as well as its sulcal (inward-facing) and anti-sulcal (outward-facing) parts. The ultrastructure of the sagitta shows that not all of the optical and etched checks in the central growth axis represent true discontinuities in the crystal growth of the otolith; they are the result of refraction around narrow optically active refractive bands. Microincrement growth along the dorsal prisms of the otolith from the primordium to the growing edge shows discontinuities in crystal growth at the boundary of the primordium and at the intersection of prisms. Parts of the ventral edge of the otolith show discontinuous crystal growth apparently caused by the physical growth restriction at the point at which the otolith is supported by the skull. Both the anti-sulcal and sulcal parts of the otolith often show discontinuities in the crystal structure alongside zones of continuous microincrement deposition, or evidence of continuous crystal growth, documenting simultaneous continuous and discontinuous growth in closely juxtaposed parts of the same otolith. © 1993 Wiley-Liss, Inc.
    Additional Material: 16 Ill.
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    Androgen effects on vocal muscle structure in a teleost fish with inter- and intra-sexual dimorphism (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 305-318 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The plainfin midshipman fish Porichthys notatus has both interand intra-sexual dimorphism in the sound-producing (vocal or sonic) muscles attached to the swimbladder wall. The “Type I” and “Type II” male morphs differ in that dramatic structural changes related to sexual maturity occur in the mass, the area of mitochondria-filled sarcoplasm, and the myofiber number of the sonic muscles of Type I males, but not in those of Type II males (nor of females). Androgen implantation for 9 weeks markedly increased the relative sonic muscle size in juvenile males, juvenile females, and Type II males, whereas estradiol or cholesterol treatment did not. The principal androgen effect on myofiber structure was an increase in the area of mitochondria-filled sarcoplasm. The ratio of sarcoplasm area to myofibril area (Sr/Mf) increased by 1.4- to 2-fold in myofibers of all androgen-treated groups, with the greatest structural change occurring in juvenile males. When androgen implants were removed from juvenile males, the muscle mass and Sr/Mf ratio reverted toward the unimplanted juvenile phenotype. Total fiber number in sonic muscle increased significantly in juvenile males following androgen implantation but did not detectably change in juvenile females or Type II males. These results suggest: (1) sonic muscle in Porichthys notatus is an androgen target tissue, (2) fiber structure and fiber number are androgen-sensitive features, and (3) there exist sex- and morph-specific patterns of sonic muscle responsiveness to androgen implants. © 1993 Wiley-Liss, Inc.
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    Ultrastructural localization of RNA in the chromatoid bodies of undifferentiated cells (neoblasts) in planarians by the RNase-gold complex technique (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 319-326 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Undifferentiated cells of planarians (Platyhelminthes, Turbellaria), also called neoblasts, are totipotent stem cells, which give rise to all differentiated cell types, while maintaining their own density by cell proliferation. Neoblasts are the only somatic cells of planarians bearing chromatoid bodies in their cytoplasm; these organelles disappear as differentiation takes place. Studies on germinal cells of several groups of organisms have shown that chromatoid bodies contain substantial amounts of RNA. To test its presence in neoblasts, we have used an RNase-gold technique. We found chromatoid bodies labeled with RNase-gold particles. Heterogeneity in the density of the label, may be correlated with the functionality and complexity of these organelles. The gold marker was also present over the nucleus and rough endoplasmic reticulum, but mitochondria, secretory granules, and the extracellular space were devoid of label. This specific localization of RNA in planarian chromatoid bodies supports earlier findings on germ cells and embryonic cells in a variety of organisms, indicating that chromatoid bodies are information-storage structures, essential during the process of cell differentiation. © 1993 Wiley-Liss, Inc.
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    Osmoregulatory-like mitochondria-rich cells in the developing pancreatic ducts of young anuran tadpoles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 339-350 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Pancreatic ducts of young posthatching Rana temporaria tadpoles are the main component of the developing pancreas. At this stage (free-swimming tadpoles with internal gills), duct cells display a high degree of development of basal and lateral outfoldings of the cell membrane with extensive interdigitation, and numerous mitochondria are present throughout the cytoplasm. Wide intercellular spaces also exist, sometimes forming canaliculi-like structures. Since these traits are characteristic of cells engaged in osmotic regulation, we suggest the possibility that this temporary duct system participates in such control. Duct cells in tadpoles with well-developed hindlegs have diminished interdigitation, and mitochondria are localized apically. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993) 
    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.1052170101
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    Distribution and morphology of motoneurons innervating different muscle fiber types in an amphibian muscle complex (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 327-338 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution and morphology of motoneurons innervating specific types of muscle fibers in the levator scapulae superior (LSS) muscle complex of the bullfrog (Rana catesbeiana) and tiger salamander (Ambystoma tigrinum) were studied by retrograde labelling with cholera toxin-conjugated horseradish peroxidase (CT-HRP). The LSS muscle complex in both of these amphibians has a segregated pattern of muscle-fiber types (tonic; fast oxidative-glycolytic twitch [FOG]; fast glycolytic twitch [FG]) along an anteroposterior axis. The entire motor pool was labelled by injection of CT-HRP into the whole LSS muscle complex. The motoneurons innervating specific fiber types were labelled by injection of CT-HRP into certain muscle regions. The organization of the motoneuron pool of the LSS complex of both species was arranged in two columns - one ventrolateral and one medial. In bullfrogs, the ventrolateral column contains motoneurons innervating FG and tonic fiber types and the medial column contains motoneurons innervating FOG fiber types. In tiger salamanders, the ventrolateral column contains motoneurons innervating FG fiber types and the medial column contains motoneurons innervating FOG and tonic fiber types. The different motoneuron types also have different soma sizes and patterns of dendritic arborization. In both species, FG motoneurons are the largest, whereas FOG motoneurons are intermediate in size and tonic motoneurons are the smallest. In bullfrogs, the main dendrites of FG motoneurons extend into the dorsolateral and the ventrolateral gray matter of the spinal cord, whereas the dendrites of FOG motoneurons extend into the ventral and medial cord. In the tiger salamander, dendrites of FG motoneurons extend into the ventrolateral spinal cord and dendrites of the FOG motoneurons extend more generally into the ventral cord. Dendrites of tonic motoneurons in both amphibians were small and short, and difficult to observe. These results establish that motoneurons innervating different types of muscle fibers in the LSS muscle complex are segregated spatially and display consistent morphological differences. © 1993 Wiley-Liss, Inc.
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    Ultrastructure of the cardiac and pyloric glands of the gastric mucosa of the South African hedgehog, Atelerix frontalis (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 351-359 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cardiac and pyloric glands in the gastric mucosa of the South African hedgehog, Atelerix frontalis, are described. The cardiac area of the stomach contains proper cardiac glands and lacks undifferentiated fundic glands. The cardiac glands are simple tubular, coiled, and lined with columnar cells ultrastructurally similar to those of the gastric surface epithelium. Secretory granules with varying electron densities fill the apical cytoplasm of these cells. In contrast to other mammals, these glands lack mucous neck cells. The neck of the pyloric glands contains only a single cell type, whereas the basal regions of these glands contain “light” and “dark” cells. The secretory granules in the “dark” cells and the pyloric neck cells have a moderate electron density and often contain an electron dense core. An electron-lucent cytoplasm with numerous polysomes is characteristic of the “light” cells. Some “light” cells contain electron-dense granules in the apical cytoplasm. The presence of only neutral mucins in the cardiac gland cells denotes the absence of mucous neck cells. The acidic mucins within the pyloric neck cells seem to indicate that these cells are mucous neck cells, whereas the neutral mucins within the basally located pyloric gland cells show at least a partial functional difference from the pyloric neck cells. © 1993 Wiley-Liss, Inc.
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    Jaws and teeth of american cichlids (Pisces: Labroidei) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 1-36 
    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 upper, lower, and pharyngeal jaws is very similar among American cichlids. Common conditions are: (1) the presence of a premaxillary dentigerous arm shorter than the ascending arm (exceptions are Astronotus, Cichla, and Crenicichla semifasciata), (2) a narrow coulter area; in contrast, a broad coulter area is found in the Crenicichline Group, in certain chaetobranchines, and in Apistogramma, (3) the mandibular sensory canal exists to the skin through five or six simple pores; in contrast, it exits through numerous small pores that increase in number during ontogeny in the Chaetobranchine Group, certain crenicichlines, such as Cichla, Crenicichla lepidota, Crenicichla proteus, and Crenicichla vittata, and certain genera of the Cichlasomine Group A, such as Caquetaia, Petenia, Neetroplus, and “Cichlasoma,” and (4) the premaxilla and dentary of American cichlids commonly bear unicuspid, conical teeth with a few exceptions such as Neetroplus (with scraping blade teeth) and “Cichlasoma” facetum, “C.” cyanoguttatum, “C.” guttulatum, and “C.” spilurum (with bicuspid [hooked] teeth). In contrast to the near uniformity of the upper and lower jaws, the upper and lower pharyngeal jaws present a great diversity of tooth shapes. At least seven types are found in American cichlids; usually, several types exist on a single tooth plate, but the combination of tooth types differs among some genera.The pharyngobranchial 4 tooth plate has significant evolutionary transformations in labroids. The caudal margin of the pharyngobranchial 4 tooth plate bears the frayed zone in cichlids and embiotocids. The presence of a broad frayed zone bearing one to seven concavities represents a synapomorphy for the family Cichlidae, whereas a deep, narrow frayed zone is a synapomorphy of Embiotocidae. The absence of the frayed zone is a synapomorphy of Pomacentridae, whereas the loss of the pharyngobranchial 4 is a synapomorphy of Labridae. © 1993 Wiley-Liss, Inc.
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    Fine structure of the nephridial muscle layer cells of Phascolosoma granulatum (Sipuncula) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 45-54 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nephridial muscle layer of Phascolosoma granulatum consists of a network of longitudinal and circular cells separated by connective tissue matrix. The muscle fibers are densely packed with thick and thin myofilaments, among which are scattered cytoplasmic dense bodies. The nucleus and noncontractile cytoplasmic organelles occupy a lateral projection from the contractile portion of the fiber. Cytoplasmic dense bodies are the result of a clustering of an indeterminate number of the thin actin filaments that fill the cytoplasm between thick filaments. Attached to the cytoplasmic face of the cell membrane are membrane-associated electron-dense plaques. These sites are linked to the contractile myofilaments by narrow filamentous bridges. Extracellular narrow filaments extend from these plaques to collagen fibers of the connective tissue matrix. Differences in length of the dense plaques may be related to differences in thick myofilament diameter in three types of muscle fiber, types A, B and C, statistically distinguished by mean fiber size differences. The plaques may serve as connecting links for the transmission of tension from contractile units to the connective tissue of the muscle layer. © 1993 Wiley-Liss, Inc.
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    Muco-follicle cells of the jelly coat in the oocyte envelope of the sheatfish (Silurus glanis L.) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 37-43 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During early vitellogenesis of the oocytes of Silurus glanis, the follicular cells proliferate, their epithelial organization becomes disrupted, and they transform into an irregularly structured large mass of cells engaged in intensive secretory activity. They contain nuclei, rough endoplasmic reticulum, Golgi bodies, and secretory inclusions termed “acorn bodies,” which are synthesized in the cytoplasm. The acorn bodies have two components: an electron-dense cap and a moderately electron-dense body. As development proceeds, the acorn bodies become modified into spherules of mucous material, the mucosomes. The electron-dense part persists as a small calotte or crescent often irregularly structured at the periphery of the mucosome, and fragments of it are dispersed into the interior of the mucosomal body. The mucosomes are membrane-bound and contain small granules, 55 nm in diameter.At the end of vitellogenesis, the follicle cells are filled with mucosomes, and cytoplasmic residua can only sparingly be observed among them. Oocytic microvilli extend through the zona radiata and intermingle with follicular cell processes in the cleft between the zona radiata and the belt of mucosomes during growth of the oocyte. Capillaries develop in connective tissue of the theca layer as vitellogenesis proceeds. © 1993 Wiley-Liss, Inc.
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    Scaling of cursoriality in mammals (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 55-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Data on limb bone lengths from 64 mammalian species were combined with data on 114 bovid species (Scott, '79) to assess the scaling of limb lengths and proportions in mammals ranging from 0.002 to 364 kg. We analyzed log-transformed data using both reduced major axis and least-squares regression to focus on the distribution across mammals of two key traits - limb length and metatarsal/femur ratio - associated with cursorial adaptation. The total lengths of both fore and hindlimbs scale in a manner very close to the M0.33 predicted by geometric similarity. Thus the relative limb lengths of large mammals, including bovids, generally regarded among the most cursorial of mammals, are very similar to those of the rodents and insectivores in this sample. Metatarsal/femur ratio also shows little change with changing mass, although bovids tend to have relatively longer metapodials than do other families in the sample. We argue that many of the remaining morphological traits associated with cursoriality (e.g., reduction in joint mobility and number of distal limb bone elements) promote cursoriality only at large body sizes. These results lead us to question the general perception that cursoriality is most widespread among large mammals. We also suggest that discussions of cursoriality should focus explicitly on the two partially independent aspects of performance that are otherwise confounded under this general term - speed and the ability to cover substantial distance. © 1993 Wiley-Liss, Inc.
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    Histomorphometry of immature rat testis after heating (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 65-74 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The scrotal testes of albino rats aged 35 and 45 days were immersed in water at constant temperatures of 43°C, 44°C, or 45°C for periods of 15-45 min in a special heating device. At an age of 60 days, the rats were mated in individual cages with two primiparous rats each. At an age of 90 days, they were killed and their testes were histologically processed. Rats with testes that had been subjected to heating when the animals were 45 days old showed both alterations of the seminiferous tubules and a decrease in fertilizing capacity. The effect of heat was greater in animals at 45 than at 35 days of age. In heat-treated testes, tubules contained PAS-positive concretion, sometimes engulfed by macrophage-derived giant cells and multinucleate cells derived from spermatids that failed to separate during spermiogenesis. The decrease in testicular volume observed after heat treatment was due mainly to reduced parenchymal volume. Thermic lability of seminiferous stem cells increases with age until adulthood, and recovery from heat injury declines. © 1993 Wiley-Liss, Inc.
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    Electromyographic and kinematic studies of tail movements in dogs during treadmill locomotion (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 105-113 
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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: Electromyographic (EMG) activities of three tail muscles, the extensor caudae lateralis (ECL), abductor caudae externus (ACE), and flexor caudae longus (FCL), were recorded bilaterally in seven adult dogs during walking, trotting, and galloping on a treadmill. Each dog's movements were recorded with a 16 mm high-speed camera system, and angular movements of the tail were analyzed. During walking and trotting, reciprocal EMG bursts were observed between right and left tail muscles and corresponded with lateral movements of the tail.The tonic discharges that were observed in ECL and FCL seemed to maintain the position of the tail. During galloping, synchronized EMG activity of all tail muscles produced reactive torques to counter those generated by cyclic limb movements and kept the tail in a stable position. These results suggest that tail movements are important in maintaining body balance during locomotion in the dog. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170109
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    Ultrastructural study of the mental body of Hydromantes genei (Amphibia: Plethodontidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 75-86 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mental glands of Hydromantes genei are considered a specialized form of the urodele serous cutaneous glands. Use of a variety of techniques of maceration and digestion as well as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) has shown the three-dimensional morphology of secretory and myoepithelial cells. Secretory cells are pyramidal and rest on an almost continuous layer of myoepithelial cells. The latter have a long ribbon-like body from which branch off transversal and longitudinal processes with swallow-tailed ends. Cytoplasmic processes of secretory cells, containing irregular dense vesicles, squeeze through clefts between myoepithelial cells and may reach, at some points, the basal lamina. The interstices between myoepithelium and secretory cells are extraordinarily rich in nerve endings with clear vesicles. The glandular outlets appear as elliptical stomata in the superficial layer of the epidermis and are lined by horny cells, which invaginate to circumscribe the excretory duct. The morphological results indicate that the myoepithelium of Plethodontidae mental glands differ in some respects from that of amphibian serous cutaneous glands. A double polarity for the secretory cells is also suggested. © 1993 Wiley-Liss, Inc.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170107
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    Differentiation of cytoplasmic organelles and storage of yolk during vitellogenesis in Hemidiaptomus ingens and Mixodiaptomus kupelwieseri (Copepoda, Calanoida) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 87-103 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: These investigations concern two freshwater calanoid copepods Hemidiaptomus ingens and Mixodiaptomus kupelwieseri. The first aspect of the research relates to the processes involved in the formation and the differentiation of the ooplasmic organelles at the time of primary vitellogenesis. During this phase, a number of complex associations develop in the ooplasm. They consist chiefly of nuage-like structures, corresponding to extruded nuclear material, and vesicular formations, some arising from the nuclear envelope and the others neoformed in the ooplasm. These associations represent centers of maturation for ribosomes and synthesis for reticulum membranes. Annulate lamellae may be observed near these associations. Biogenesis of the reticulum always precedes the differentiation of the Golgi apparatus. Indeed, the dictyo-somes develop in characteristic complexes including endoplasmic reticulum cisternae and numerous vesicles resulting from intensive blebbing from cisternae. The second aspect of this research concerns yolk synthesis and accumulation of hyaloplasmic inclusions. A preliminary synthesis of yolk occurs early in these complexes and becomes more important after achievement of Golgi apparatus biogenesis. However, the most important yolk storage results from exogenous molecules and consists of complex globules, which develop into the ooplasm during secondary vitellogenesis. Formation of these globules is associated with the accumulation of two categories of inclusions in the hyaloplasm, i.e., lipid droplets and clusters of glycogen particles. At the end of vitellogenesis, a new type of endogenous material develops into small cisternae localized in the cortical ooplasm. © 1993 Wiley-Liss, Inc.
    Additional Material: 31 Ill.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993) 
    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.1052170201
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    Spermathecal cytology of Ambystoma opacum (Amphibia: Ambystomatidae) and the phylogeny of sperm storage organs in female salamanders (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 115-127 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sperm storage glands, spermathecae, were examined from mated female Ambystoma opacum during the breeding season. No differences occur in the spermathecal ultrastructure of individuals sacrificed prior to oviposition and those sacrificed within 3 days of removal from tended clutches of recently oviposited eggs. The simple tubuloalveolar glands produce two types of secretory vacuoles. Apical secretory vacuoles contain glycosaminoglycans for export into the lumen to bathe stored sperm, perhaps providing the chemical/osmotic environment necessary for sperm quiescence. The other type of secretory vacuole contains an unsaturated lipid that is produced for export into the connective tissue surrounding the spermathecae. The role of this secretion may involve the contraction of myoepithelial cells, resulting in sperm expulsion. Some sperm undergo degradation in the spermathecal epithelium, and an interepithelial leukocyte was observed in one specimen. Apical secretory vacuoles and sperm are absent from the spermathecae of a specimen sacrificed 62 days after removal from a tended egg clutch. This is the first report on the spermathecal cytology of a salamander from the Ambystomatidae, and comparisons with salamanders from other families provide a morphological basis for considering spermathecae polyphyletic within the Caudata. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170110
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    Central projections of cheliceral mechanoreceptors in the spider Cupiennius salei (Arachnida, Araneae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 129-136 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Central projections of lyriform organs and tactile hairs on the chelicerae of the wandering spider Cupiennius salei were traced using anterograde cobalt fills. Different fibers arising from both mechanoreceptor types arborize in the cheliceral ganglia, which are part of the tritocerebrum, and in sensory longitudinal tracts in the center of the suboesophageal nerve mass together with afferent fibers arising from mechanoreceptors on the walking legs and the pedipalps. This convergence of sensory projections in the sensory longitudinal tracts might provide the anatomical basis for the coordination of the movements of different extremities during prey capture and feeding. The findings also support the hypothesis that the tritocerebrum originally was a preoral ganglion in spiders. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170202
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    Trigeminal primary afferent projections to the spinal cord of the frog, Rana ridibunda (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 137-146 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution in the spinal cord of the trigeminal primary projections in the frog Rana ridibunda was studied by means of the anterograde transport of horseradish peroxidase (HRP). Upon entering the medulla via the single trigeminal root, a conspicuous descending tract that reaches the cervical spinal cord segments is established. This projection arises in the ophthalmic (V1), maxillary (V2), and mandibular (V3) trigeminal nerve subdivisions. In the spinal cord, only a minor somatotopic arrangement of the trigeminal fibers was observed, with the fibers arising in V3 terminating somewhat more medially than those from V1 and V2. A dense projection to the medial aspect of the spinal cord, above the central canal, primarily involves V3. Each trigeminal branch sends projections at cervical levels to the contralateral dorsal field, and those from V2 are most abundant. Bilateral experiments with HRP application show convergence of primary trigeminal and spinal afferents within the dorsal field of the spinal cord.The pattern of arrangement of the trigeminal primary afferent fibers in the spinal cord of this frog largely resembles that of amniotes. However, the organization seems simpler and the slight somatotopic distribution of V1, V2, and V3 fibers is similar to the condition in other anamniotes. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170203
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    Internal micromorphology of the frons plate in females of the oriental hornet (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 147-159 
    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 and energy dispersive x-ray analysis (SEM/EDS) have been used to study the internal micromorphology of the frons plate in the Oriental hornet, Vespa orientalis. A conical shaped organ was described which is recessed into the frons plate and projects toward the interior of the acoustic box. The latter is located on the inner side of the frons plate. On the exterior of the conical region are observed aggregates containing Ca and Si, and a thin transparent membrane bearing a hole in its center. The innermost surface of the conical structure terminates bluntly as a convex lentiform tip, bearing a transparent oval-shaped window in its center. The conical organ, excepting the window, is enclosed in several layers of epithelium.The structure of this many-layered conical organ is highly complex; its numerous sub-structures and the possible role as a gravity sense organ are discussed. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170204
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    Ultrastructure of the light organ and immunocytochemical localization of luciferase in luminescent marine ostracods (Crustacea: Ostracoda: Cypridinidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 181-193 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the upper lip, which is the location of the light organ in luminescent ostracods, is described for two species of marine ostracods (Vargula graminicola, and V. tsujii). The light organ contains four primary cell types (here designated A-D) readily identified both by the types of vesicles that they contain and their location. Cell type A, restricted to the center of the light organ, has vesicles that are homogeneous throughout. Cell type B has vesicles with a single electron-dense central area. This cell is most common in the lateral regions but is also found in the tusks. Immunocytochemical experiments revealed that luciferase is found in B cells, but not in any other cells or in control specimens. Cell type C has vesicles containing many electrondense microstructures; this cell type is the least common and is found along with B cells within the lateral margins of the light organ. Cell type D has granulated vesicles and is restricted to the tusks. Metachromatic staining with toluidine blue suggests that the vesicles contain acidic mucosubstances. The cells of the light organ are very long (360-460 μm) and extend through its entire length. The cells found exclusively in the tusks are shorter (ea. 150 μm). All cells possess similar polarity: proximal synthesis, middle transitional, and distal secretory regions. These cells terminate ventrally at nozzles on the anterior portion of the upper lip, and on the tusks. The upper lip and light organ possess two large longitudinal muscles, a central muscle, and several smaller “bridle” muscles that attach onto sclerotized ridges. Various hypotheses for the storage and secretion of light organ materials are suggested relative to these morphological data. © 1993 Wiley-Liss, Inc.
    Additional Material: 18 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180207
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    Stages of oocyte development in the zebrafish, Brachydanio rerio (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 203-224 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oocyte development has been divided into five stages in the zebrafish Brachydanio rerio, based on morphological criteria and on physiological and biochemical events. In stage I (primary growth stage), oocytes reside in nests with other oocytes (Stage IA) and then within a definitive follicle (Stage IB), where they greatly increase in size. In stage II (cortical alveolus stage), oocytes are distinguished by the appearance of variably sized cortical alveoli and the vitelline envelope becomes prominent. In stage III (vitellogenesis), yolk proteins appear in oocytes and yolk bodies with crystalline yolk accrue during this major growth stage. Ooctes develop the capacity to respond in vitro to the steroid 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) by undergoing oocyte maturation. In stage IV (oocyte maturation), oocytes increase slightly in size, become translucent, and their yolk becomes non-crystalline as they undergo final meiotic maturation in vivo (and in response to DHP in vitro). In stage V (mature egg), eggs (approx. 0.75 mm) are ovulated into the ovarian lumen and are capable of fertilization. This staging series lays the foundation for future studies on the cellular processes occurring during oocyte development in zebrafish and should be useful for experimentation that requires an understanding of stage-specific events. © 1993 Wiley-Liss, Inc.
    Additional Material: 34 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180209
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    Quantitative investigations of spinal motoneurons and their synaptic structures in a teleost: A morphometrical analysis with special reference to axosomatic synapses (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 281-300 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructural and morphometrical synaptology of the spinal motoneurons in Carassius auratus (goldfish) was analyzed based on profiles of 23 photomontages of large motoneurons and 25 putative small motoneurons with a semiautomatic digitizing system connected with a computer. In the 23 large motoneurons (mean circumference, 142.45 ± 39.76 μm) the total linear perikaryal circumference was 3,276.28 μm, of which 1,548.9 μm (46.1 ± 13.9%) was covered by terminal boutons. In contrast, a total linear perikaryal circumference of 1,375.24 μm (55.01 ± 14.34 μm) of the 25 putative small motoneurons was covered with terminal boutons only occupying a length of 287.45 μm (19.8 ± 11.9%). There were a total of 1,045 boutons on the large motoneurons and 204 on the small ones. The distribution of S- and F-type boutons may reflect excitatory and inhibitory synapses. The relative number of S-type boutons (58%) was larger than that of F-type boutons (42%) in the large neurons and showed similar values (S-type, 57%; F type, 43%) in the small ones. This is in contrast to mammalian spinal motoneurons in which F-type boutons are more prevalent than the S-type. The total numbers of the axosomatic boutons in large and small neurons were estimated, based on geometrical assumptions and found to differ substantially (840 vs. 59). This indicates large quantitative differences in the total number of synaptic inputs with the large motoneurons having a greater more axo-somatic bouton density. No large M- and C-type boutons occur on the spinal motoneurons of goldfish, suggesting a synaptic organization which is simple compared to that of terrestrial vertebrates. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180305
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    Distribution of calcium-ATPase in developing teeth of embryonic American alligators (Alligator mississippiensis) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 249-256 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light microscopic and ultrastructural observations were carried out to evaluate the cell morphology and histochemistry (calcium-ATPase activity) of developing teeth in embryonic American alligators (Alligator mississippiensis). Ca-ATPase activity was observed in the distal and lateral cell membranes, rough endoplasmic reticulum (rER), mitochondria, vacuoles, and other organelles of the ameloblast, but only in the distal cell membrane and process of the odontoblast. Enzyme activity in the ameloblasts increased gradually during development. These sites of enzyme activity are related to mineralization of the enamel layer, similar to that in mammalian tooth development. Alligator teeth are heavily mineralized like mammalian teeth; however, alligator ameloblasts have undeveloped distal processes during mineralization in contrast to mammalian ameloblasts in which Tomes' processes are found near the distal portion of ameloblasts at maturation stage. The localization of intense enzyme activity in the distal and lateral ameloblast cell membrane suggests that these regions are the site of accumulation of calcium as enamel differentiates in the developing tooth. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052180303
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    Action of tolytoxin on cell morphology, cytoskeletal organization, and actin polymerization (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 39-48 
    Details
    ISSN: 0886-1544
    Keywords: actin ; microfilament ; stress fiber ; cytochalasin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tolytoxin, a cytostatic, antifungal macrolide produced by blue-green algae of the genus Scytonema, is a potent, reversible inhibitor of cytokinesis in cultured mammalian cells. Treatment of KB cells with 2-16 nM tolytoxin results in profound morphological changes, beginning with the formation of zeiotic processes and culminating in nuclear protrusion. In L1210 cells, cytokinesis is inhibited by as little as 2 nM tolytoxin, while karyokinesis proceeds normally, resulting in polynucleation. Tolytoxin specifically disrupts microfilament organization in A10 cells, while having no apparent effect on microtubules or intermediate filaments. Tolytoxin inhibited actin polymerization in vitro and also caused the depolymerization or fragmentation of F-actin in vitro. Tolytoxin exhibits effects that closely resemble those of cytochalasin B but is effective at concentrations 1/50-1/1,000 that of cytochalasin B. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970240105
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    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.970240201
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    Native microtubules with a variable number of protofilaments (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 49-53 
    Details
    ISSN: 0886-1544
    Keywords: insect sperm tail ; trichopteran axoneme ; computer image analysis ; axonemal ultrastructure ; accessory tubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Insect spermatozoa are characterized by having a set of accessory tubules that surrounds the microtubular doublets of the axoneme and that are formed from the B-subtubules of the doublets. In trichopteran species, the accessory tubules have an unusually large diameter. Those of one species, Odontocerum albicorne, were seen to have a number of protofilaments that is 19 in the main part of the axoneme, but gradually decreasing to 18, 17, and 16 near the distal tip. The accessory tubule of the trichopteran axoneme has an asymmetrical shape and a skewed orientation, which makes it easy to distinguish a tubule that is viewed from its plus-end from one viewed from the minus-end. The shape of a cross-sectioned protofilament in the trichopteran accessory tubules differs from that of microtubules in general, including accessory tubules of other insects, by being polygonal with the most acute angle pointing centripetally. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970240106
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    Molecular cloning and expression of the chicken smooth muscle γ-actin mRNA (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 67-81 
    Details
    ISSN: 0886-1544
    Keywords: development ; cDNA ; actin isoform ; enteric ; myogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the expression of chicken smooth muscle γ-actin mRNA by isolation and characterization of cDNAs representing this actin isoform and utilizing the cDNA to probe RNA from adult and developing cells. Nucleotide sequence elucidated from an apparent full length smooth muscle γ-actin cDNA revealed that it contained 94 bp of 5′ non-translated sequence, an open reading frame of 1131 bp, and 97 bp of 3′ non-translated sequence. Within the 376 amino acid sequence deduced from the chicken cDNA were diagnostic amino acids at the NH2- and COOH-terminal regions which provided unequivocal identification of the γ-enteric smooth muscle actin isoform. In addition, the chicken γ-enteric actin deduced from our cDNA clones was found to differ from the sequence reported in earlier protein studies [J. Vandekerckhove and K. Weber, FEBS Lett. 102:219, 1979] by containing a proline rather than a glutamine at position 359 of the protein, indicating that the avian γ-enteric actin isoform is identical to its mammalian counterpart. Comparison of the 5′ and 3′ non-translated sequence determined from the chicken cDNA to that elucidated for rat, mouse, and human showed that there is not a high degree of cross-species sequence conservation outside of the coding regions among these mRNAs. Northern hybridization analyses demonstrated that the γ-enteric actin mRNA is expressed in adult aorta and oviduct tissues but not in adult skeletal muscle, cardiac muscle, liver, brain, and spleen tissues. The γ-enteric actin mRNA was first observed in measurable quantities in gizzard tissue from 4-5 day embryos and increased in content in developing smooth muscle cells through 16-17 embryonic days. Following this initial increase during embryonic development, the γ-enteric actin mRNA exhibits a decline in content until ∼7 days posthatching, after which there is an increase in content to maximal levels found in adult gizzard tissue. In general, the developmental appearance of the γ-enteric mRNA parallels that observed for this protein in previous studies indicating that the developmental expression of smooth muscle γ-actin is regulated, in part, by an increased content of mRNA in chicken visceral smooth muscle cells during myogenesis. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970240108
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    Protein kinases are required for embryonic neural crest cell galvanotaxis (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 54-66 
    Details
    ISSN: 0886-1544
    Keywords: protein kinase ; galvanotaxis ; motility ; phorbol ester ; neural crest ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryonic quail neural crest cells migrate towards the negative pole of an imposed dc electric field as small as 7 mV/mm (0.4 mV per average cell length). The involvement of protein kinases in the mechanism utilized by these cells to detect and respond to such imposed fields was tested through the use of several kinase inhibitors. Evidence for the involvement of protein kinase C (PKC) included: (1) inhibition of the directed motility by 1 μM sphingosine that was reversed by the addition of the phorbol ester, PMA; (2) stimulation of a faster response to the imposed field by PMA; and (3) inhibition of the directed translocation by 5 μM H-7. However, another PKC inhibitor, staurosporin, did not inhibit the directed translocation (1 nM-1 μM). We also found evidence for the involvement of either cAMP- or cGMP-dependent protein kinase. The galvanotactic response was partially inhibited by the addition of 10 μM H-9 and the response was enhanced in the presence of the phosphodiesterase inhibitor, IBMX. However, the adenylate cyclase stimulant, forskolin, had no significant influence on the directed motility, although it reduced the average cell velocity. While these experiments suggest that cAMP- or cGMP-dependent protein kinase or PKC may be involved in the galvanotaxis response, two other protein kinases appeared not to be required. The myosin light chain kinase inhibitor, ML-7, had no effect on the directed motility in an imposed field, so myosin light chain kinase may not be required for galvanotaxis. Similarly, 5 μM W-7 had no significant effect on the directed translocation, suggesting that calmodulin-dependent protein kinase is not involved.Interestingly, the continuous activity of a protein kinase is apparently not required for the directed translocation response. The addition of the PKC and cAMP-dependent protein kinase inhibitor, H-7, after the cells had been exposed to the field for 1 hour, had no effect on the subsequent directed translocation. Thus, for these inhibitors to block the directed translocation, they must be present at the same time as the initial field application. This implies that an integral step in the cellular response mechanism for galvanotaxis involves the stimulation of a protein kinase whose effect is long lasting. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970240107
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    Actin-binding protein is a component of bovine erythrocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 100-108 
    Details
    ISSN: 0886-1544
    Keywords: actin-binding protein ; filamin ; erythrocytes ; membrane skeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Actin-binding protein (ABP) is a well-characterized polypeptide capable of crosslinking filamentous actin. To date, this polypeptide has been shown to exist in a number of tissues and cultured cell lines. This report shows that by using a panel of three monoclonal antibodies for immunoblotting and immunofluorescence analysis, that ABP is present in bovine erythrocytes. Moreover, the data obtained suggest that this protein is a component of the erythrocyte membrane skeleton. Additionally, bovine erythrocyte ABP is shown to possess both an apparent molecular weight and an isoelectric point identical to that of bovine smooth muscle filamin, implying that these two polypeptides are identical. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970240203
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  • 90
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    Cytoskeletal sheets of mammalian eggs and embryos: A lattice-like network of intermediate filaments (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 85-99 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeletal sheets ; intermediate filaments ; blastomere - blastomere contact ; cross-bridges ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mammalian eggs and embryos possess a major cytoskeletal network composed of large planar “sheets” distributed throughout the cytoplasm. Cytoskeletal sheets are found neither in mammalian somatic cells nor in eggs or embryos of non-mammals. In this study, we have investigated the structural composition of the sheets in eggs and embryos of the golden Syrian hamster by (1) analysis of replicas from quick-frozen, deep-etched specimens, (2) analysis of thick, resinembedded specimens using an intermediate voltage electron microscope (IVEM), (3) laser diffraction of EM images, (4) differential extraction with detergents, and (5) immunocytochemistry. Our results indicate that each sheet is composed of two closely apposed arrays of 10-nm filaments. Each filament within an array is held in register with its neighbor by lateral cross-bridges and the two parallel arrays of filaments are interconnected by periodic cross-bridges about 20 nm in length. Laser diffraction of negatives from IVEM images indicates that each array is composed of fibers that form a square lattice, and the two arrays are positioned in register by cross-bridges forming a single sheet. This lattice forms the skeleton of the sheets which is covered with a tightly packed layer of particulate material. By incubation in media containing different ratios of mixed-micelle detergents, it is possible to remove components sequentially from the sheets and to extract the particulate material. Immunocytochemical localization demonstrates that the sheets bind antibodies to keratin, and to a small extent actin, but do not bind antibodies to vimentin or tubulin. Examination of sheets within embryos at the time of embryonic compaction demonstrates that the sheets begin to fragment and disassemble in regions of blastomeres where desmosomes form, but undergo no structural alterations in interior and basal surfaces of the blastomeres. In regions of blastomere - blastomere contact the sheets fragment and associate with granules resembling keratohyalin granules found in keratinocytes. © 1993 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240202
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  • 91
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    Morphology of nexin links in relation to interdoublet sliding in the sperm flagellum (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 109-118 
    Details
    ISSN: 0886-1544
    Keywords: motility ; flagellum ; spermatozoon ; nexin ; freeze-etch ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this work, we examine whether the “nexin” linkages of the flagellum can extend in length to accommodate interdoublet sliding. Flagellar bends of large angle were induced in bull spermatozoa by hypotonic treatment. It is argued that this produces large interdoublet displacements that are, nevertheless, still within physiological limits. Such flagella were examined by the rapid-freeze, deep-etch techique and the nexin linkages identified by their position in relation to the inner dynein arms and by their straplike, bipartite, morphology. They were found to bridge perpendicularly (or occasionally at an angle) between the A- and B-tubules of adjacent doublets. The nexin linkages were no more than ∼20 nm in length, even in regions in which ∼200 nm of sliding could be inferred. Variable registration between adjacent nexin rows gave some further support to the assumption that sliding had indeed taken place. From this, it is concluded that elastic deformation of the links, such as would accommodate interdoublet sliding, does not occur; some form of displacement must occur between nexin and the adjacent B-tubule. © 1993 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970240204
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  • 92
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    Incorporation of microinjected mutant and wildtype recombinant tropomyosins into stress fibers in fibroblasts (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 119-128 
    Details
    ISSN: 0886-1544
    Keywords: actin ; actin filament assembly ; actin binding sites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural requirements for assembly of tropomyosin into stress fibers were investigated by microinjecting wildtype and four mutant striated chicken muscle α-tropomyosins expressed in E. coli as fusion and nonfusion proteins into cultured rat embryo fibroblasts, followed by localization of tropomyosin using indirect immunofluorescence. The results show that the determinants for stress fiber incorporation in living cells correlate with the in vitro actin affinity of these tropomyosins. Wildtype recombinant protein incorporated into stress fibers both when the amino terminus was unacetylated and when it was blocked with an 80-residue fusion protein [Hitchcock-DeGregori, S.E., and Heald, R.W. (1987): J. Biol. Chem. 262:9730-9735]. The pattern of incorporation was indistinguishable from that of tropomyosin isolated from chicken pectoral muscle. The striated α-tropomyosin incorporated into stress fibers, even though this isoform is not found in nonmuscle cells. Three recombinant mutant tropomyosins in which one-half, two-thirds, or one actin binding site was deleted were tested [Hitchcock-DeGregori, S.E., and Varnell, T.A. (1990): J. Mol. Biol. 214:885-896]. Only the fusion protein with a full actin binding site deleted incorporated into stress fibers. However, the unacetylated, nonfusion proteins with one half and one actin binding site deleted incorporated into stress fibers, consistent with the ability of troponin to promote the actin binding in vitro. A fourth mutant, in which the conserved amino-terminal nine residues were deleted, did not incorporate into stress fibers, consistent with the complete loss of function of this mutant [Cho, Y.J., Liu, J., and Hitchcock-DeGregori, S.E. (1990): J. Biol. Chem. 265:538-545]. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240205
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  • 93
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    Effects of taxol and taxol/hyperthermia treatments on the functional polarization of cytotoxic T lymphocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 129-138 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; MTOC ; centrosome ; pericentriolar material ; cytolytic activity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Immunofluorescence staining, electron microscopy, and (51Cr) cytolytic release assays are used to investigate the effects of taxol and taxol/hyperthermia treatments on the microtubule organization and cytolytic activity of cytotoxic T lymphocytes (CTLs). A 4 h treatment of CTLs with 1 μM taxol results in an extensive reorganization of the microtubule system to form one to a few large microtubule bundles that extend from the centrosome. The Golgi apparatus is not disrupted by this treatment and remains associated with the microtubule organizing centre (MTOC). This microtubule reorganization has no effect on the ability of CTLs to orient their MTOC towards a bound target cell, nor on their cytolytic activity. In control CTLs, not treated with taxol, a mild hyperthermia treatment (42°C, 30 min) results in an aggregation of the pericentriolar material, a loss of MTOC orientation, an inhibition of cytolytic activity, and a disorganization of the microtubule system [Knox et al.: Exp. Cell Res. 194:275-283, 1991]. In contrast, in taxol-treated CTLs the stabilized microtubule bundles are unaffected by such hyperthermia treatment; however, the other effects of hyperthermia appear identical in control and taxol-treated CTLs. These results indicate that a dynamic, radially arranged microtubule array is not required for the functional polarization of CTLs and suggest that a component of the pericentriolar material may play a key role in effecting MTOC orientation. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240206
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  • 94
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    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.970240301
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  • 95
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    PDGF and neomycin induce similar changes in the actin cytoskeleton in human fibroblasts (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 139-149 
    Details
    ISSN: 0886-1544
    Keywords: growth factor ; phosphatidylinositol cycle ; actin polymerization ; fluorescence microscopy ; cytochalasin D ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The addition of platelet-derived growth factor (PDGF) to serum-starved fibroblasts induces increased motility, formation of lamellipodia, increased ruffling activity, and actin ring structures associated with dorsal ruffles. Involvement of the phosphatidylinositol cycle (PI-cycle) in these morphological changes was investigated by observing the effects of neomycin, an inhibitor of the PI-cycle, on cultured human foreskin fibroblasts. The role of actin in the changes was investigated by using cytochalasin D (CD). Actin in detergent-extracted cells was labelled with TRITC-phalloidin and examined with fluorescence microscopy. Using PDGF and neomycin simultaneously potentiated lamellipodia formation, ruffling activity, as well as the number of cells with actin rings. Furthermore, neomycin by itself induced morphological changes similar to those induced by PDGF. Quantitation of actin rings showed dose and time dependency for PDGF and neomycin respectively, with a maximal number of cells containing rings after 15 min of exposure to either 3.5 mM neomycin or 10 ng PDGF/ml. Comparing the two substances, PDGF induced ring formation in a greater number of cells. These processes were inhibited by the presence of CD. PDGF- and neomycin-induced changes in the actin cytoskeleton were also observed in human embryonic lung fibroblasts, human glial cells, and embryonic mouse fibroblasts, all of which are known to express PDGF-receptors. In conclusion, the present study indicates that an increased turnover of the PI-cycle is not essential for the changes in actin organization induced by PDGF. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970240207
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  • 96
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    Divergent neural β tubulin from the antarctic fish notothenia coriiceps neglecta: Potential sequence contributions to cold adaptation of microtubule assembly (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 156-166 
    Details
    ISSN: 0886-1544
    Keywords: tubulin isotypes ; tubulin cDNA sequence ; Antarctic nototheniid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cytoplasmic microtubules of the cold-adapted Antarctic fishes, unlike those of homeotherms and temperate poikilotherms, assemble and function at body temperatures in the range -1.8 to +2°C. To determine whether alterations to the primary sequence of β tubulin may contribute to enhancement of microtubule assembly at cold temperatures, we have cloned and sequenced a 1.8-kilobase neural β-chain cDNA, Ncnβ1, from an Antarctic rockcod, Notothenia coriiceps neglecta. Based on nucleotide sequence homology, Ncnβ1 probably corresponds to a class-II β-tubulin gene. The 446-residue β chain encoded by Ncnβ1 is closely related (sequence homology ∼95%) both to the neural class-I/II isotypes and to the neural/testicular class-IV variants of higher vertebrates, but the sequence of its carboxy-terminal isotype-defining region (residues 431-446) has diverged markedly (≥ 25% change relative to the I/II/IV referents). Furthermore, the NcnβsZ1 polypeptide contains six unique amino-acid substitutions (five conservative, one nonconservative) not found in other vertebrate brain isotypes, and the carboxyterminal region possesses a unique tyrosine inserted at position 442. We conclude that Ncnβ1 encodes a class-II β tubulin that contains sequence modifications, located largely in its interdimer contact domain, that may contribute to cold adaptation of microtubule assembly. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970240303
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  • 97
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    Dynamics of microfilaments are similar, but distinct from microtubules during cytokinesis in living, dividing plant cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 151-155 
    Details
    ISSN: 0886-1544
    Keywords: carboxyfluorescein tubulin ; cell plate formation ; confocal microscopy ; phragmoplast ; rhodamine phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and dynamics of the phragmoplast cytoskeleton have been analyzed in living stamen hair cells of Tradescantia. Microtubules and actin microfilaments have been identified by microinjecting either carboxyfluorescein labeled brain tubulin or rhodamine phalloidin. Examination with the confocal laser scanning microscope has permitted sequential imaging of the fluorescent cytoskeletal elements in single living cells progressing through division. Phragmoplast microtubules initially emerge through the lateral coalescence of preexisting interzone microtubules. As cytokinesis progresses, these tightly clustered microtubules shorten in length and expand centrifugally toward the cell periphery. By contrast, the phragmoplast microfilaments appear to arise de novo in late anaphase in close association with the proximal surfaces of the reconstituting daughter nuclei. The microfilaments are oriented parallel to the microtubules but conspicuously do not occupy the equatorial region where microtubules interdigitate and where the cell plate vesicles aggregate and fuse. As development proceeds the microfilaments shorten in length and expand in girth, similar to microtubules, although they remain excluded from the cell plate region. In terminal phases of cell plate formation, microtubules degrade first in the central regions of the phragmoplast and later toward the edges, whereas microfilaments break down more uniformly throughout the phragmoplast. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240302
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  • 98
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    Microtubule-associated motility in cytoplasmic extracts of sea urchin eggs (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 167-178 
    Details
    ISSN: 0886-1544
    Keywords: cytoplasmic dynein ; kinesin ; bundling ; crosslinking ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have developed a method for producing sea urchin egg cytoplasmic extracts which support substantial microtubule-associated motility, particularly minus end-directed motility characteristic of cytoplasmic dynein. Particles translocated along microtubules and axonemes predominantly in the minus end direction; microtubules and axonemes glided across the coverslip surface only in the plus end direction (as expected for a minus-end directed motor bound to the coverslip surface); and microtubules crosslinked into bundles in an antiparallel orientation. Velocities of particle and microtubule translocation were in the range of 0.5-1.8 μm/sec. Vanadate at 10 μM inhibited all gliding of the microtubules and axonemes, yet bidirectional particle transport persisted. Vanadate at concentrations of 25 μM and higher inhibited nearly all microtubule-based motility in the preparation and produced parallel bundling of the microtubules. Motility was slowed but not stopped in the presence of 5 mM AMP-PNP.Usually when a particle bound to a microtubule wall, it moved to the microtubule minus end. These particles often remained attached to the minus end. When a microtubule plus end in the shortening phase of dynamic instability reached a stationary particle on the microtubule, sometimes normal minus enddirected motility was activated, or at other times the particle remained attached to the shortening plus end. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240304
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  • 99
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    Control of profilin and actin expression in muscle and nonmuscle cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 179-188 
    Details
    ISSN: 0886-1544
    Keywords: protein synthesis ; northern analysis ; BC3H1 cells ; HepG-2 cells ; C2C12 cells ; profilactin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Profilin is a small G-actin binding protein implicated in sequestering actin monomers in vivo. We have quantitated profilin and actin expression in human hepatoma HepG-2 cells and in two mouse myogenic cell lines, BC3H1 and C2C12, to determine whether the expression of profilin and the expression of nonmuscle isoactin or total actin are co-regulated. During differentiation of both muscle cell types, profilin and nonmuscle actin expression decrease in a coordinate manner as shown by measurements of steady state mRNA and newly synthesized protein. In human hepatoma HepG-2 cells, the twofold increase in actin synthesis observed after 24 hours of exposure to cytochalasin D did not result in an increase in profilin synthesis. Thus, profilin and actin expression are not coregulated in all cells. To determine if there is sufficient profilin to sequester a large portion of cellular G-actin, we measured total profilin and G-actin levels in the three cell types. In each case, profilin accounted for less than 10% of the total G-actin on a molar basis. Thus, profilin is not responsible for total G-actin sequestration in these cells. Finally, using poly-L-proline affinity chromatography, we showed that, in the cell types tested, less than 20% of the poly-L-proline purified profilin existed as a complex with G-actin. The profilin in these cells may be interacting with cellular components other than actin. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240305
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  • 100
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    Microinjection of fluorescent brain tubulin reveals dynamic properties of cortical microtubules in living plant cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 205-213 
    Details
    ISSN: 0886-1544
    Keywords: microtubule dynamics ; cell morphogenesis ; Nitella pseudoflabelatta ; plant cytoskeleton ; Tradescantia virginiana ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent brain tubulin, injected into living cells of the green alga Nitella pseudoflabellata and the higher plant Tradescantia virginiana, incorporates into the cortical microtubules, allowing these structures to be observed. With confocal laser scanning microscopy, clear images of microtubules were recorded and changes in microtubule patterns documented. After injection, fluorescent lengths of microtubules appeared within a few minutes and their number and length increased rapidly to a “steady state” over the first 15 min. In many instances, fluorescent microtubules could still be detected several hours after injection. In the cells examined, microtubules are arranged as an array of separate units only occasionally displaying close association or accurate co-alignment with neighboring microtubules. In what we perceive to be the steady state condition, some microtubules remain relatively static, while others undergo rapid changes in length or small translocations. We also document what appears to be bidirectional microtubule elongation during postdepolymerization assembly. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240308
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