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  • 1990-1994  (1,697)
  • 1890-1899  (23)
  • 1992  (1,697)
  • 1897  (23)
  • Cell & Developmental Biology  (1,720)
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  • 1990-1994  (1,697)
  • 1890-1899  (23)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 23-29 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Different types and degrees of “spontaneous” and artificially induced cyclopic malformation in fishes are defined. Symmetrical cyclopia ranges from approximation of the eyes, to partial merger of the eyes in the midline, to complete cyclopia with a single median eye. It is always associated with dorsal displacement of the rostral-nasal apparatus to the top of the head. Skeletal reorganization associated with symmetrical cyclopia is described for the first time, using hatchery material of Salmo gairdneri and S. trutta. Development of the nasal capsule is essentially normal, except for position; the trabeculae cranii remain in the normal position but show modified shape corresponding to the degree of cyclopia. The jaw apparatus is modified through anterior foreshortening, especially the upper jaws. The branchial apparatus is unaffected. The condition demonstrates that later morphogenesis of the nasal capsule and trabeculae cranii are independent of each other. Cyclopia appears to result from alteration of relative position and timing in developmental events in the head, especially the prosencephalon.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 201-206 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The interrenal (adrenal) of Ichthyophis beddomei lies on the ventral side of the kidney, distributed in four zones. It is separated from the renal tissue by a thin layer of connective tissue and contains both adrenocortical and chromaffin cells. Adrenocortical tissue constitutes a major portion of the interrenal islets; the chromaffin tissue consists of a few cells located at the peripheries of the interrenal islets. Histochemical studies demonstrate the presence of Δ53β-hydroxysteroid dehydrogenase, 17 β-hydroxysteroid dehydrogenase, glucose-6-phosphate dehydrogenase, succinate dehydrogenase, and sudanophilic lipids in the adrenocortical tissue, suggesting its steroidogenic potential. Annual histometric and histochemical studies show two peaks of interrenal activity: (1) during the breeding phase of the reproductive cycle (January and February) and (2) during the season of heavy monsoon rains (June and July) in the postbreeding phase.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992) 
    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
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 259-268 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The avian wrist is extraordinarily adapted for flight. Its intricate osteology is constructed to perform four very different, but extremely important, flight-related functions. (1) Throughout the downstroke, the cuneiform transmits force from the carpometacarpus to the ulna and prevents the manus from hyperpronating. (2) While gliding or maneuvering, the scapholunar interlocks with the carpometacarpus and prevents the manus from supinating. By employing both carpal bones simultaneously birds can lock the manus into place during flight. (3) Throughout the downstroke-upstroke transition, the articular ridge on the distal extremity of the ulna, in conjuction with the cuneiform, guides the manus from the plane of the wing toward the body. (4) During take-off or landing, the upstroke of some heavy birds exhibits a pronounced flick of the manus. The backward component of this flick is produced by reversing the wrist mechanism that enables the manus to rotate toward the body during the early upstroke. The upward component of the flick is generated by mechanical interplay between the ventral ramus of the cuneiform, the ventral ridge of the carpometacarpus, and the ulnocarpo-metacarpal ligament.Without the highly specialized osteology of the wrist it is doubtful that birds would be able to carry out successfully the wing motions associated with flapping flight. Yet in Archaeopteryx, the wrist displays a very different morphology that lacks all the key features found in the modern avian wrist. Therefore, Archaeopteryx was probably incapable of executing the kinematics of modern avian powered flight.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 207-212 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Analyses of the histology, histochemistry, and ultrastructre of the Harderian gland of Coluber viridiflavus prove the gland to be compound acinar and to produce a seromucous secretion. Acinar cells (type I) contain secretory granules that are composite, consisting ultrastructurally of three distinct parts that are sharply separated. They are similar to the “special secretory granules” described in the cells of the Harderian gland of the lizard Podarcis s. sicula. Some acini of the most anterior and posterior parts of the gland are mucous. Acinar cells (type II) of this type contain secretory granules that are Alcian blue/PAS positve. At the ultrastructural level, they appear homogeneous and of low density, characteristic of mucous secretions. These mucus-secreting anterior and posterior parts of the Harderian gland may by considered as regions of intial differentiation of the anterior and posterior lacrimal galnds.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 243-258 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Subdigital adhesive pads play an important role in the locomotion of many species of gekkonid lizards. These pads consist of integrated components derived from the epidermis, dermis, vascular system, subcuticular tendons, and phalanges. These components become intimately associated with each other during the developmental differentiation of the digits and the sequence of this integration is outlined herein in Ptyodactylus guttatus. The pads initially appear as paired swellings at the distal tips of the digits. Subsequently, a fan-like array of naked scansors develops on the ventral surface of each digit, at about the same time that scales differentiate over the surface of the foot as a whole. At the time of appearance of the naked scansors, the vascular sinus system of the pad also differentiates, along with subcuticular connective tissue specializations. At this stage the digits, along with the rest of the body, are clad in an embryonic periderm. Only after hatching and as the periderm is shed, do the epidermal setae and spines appear. The developmental sequence described here is consistent with predictions previously advanced about the evolutionary origin and elaboration of subdigital pads in gekkonid lizards. The paucity of available staged embryonic material leaves many questions unresolved.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 295-306 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histology, histochemistry, and biochemistry of the oviduct change seasonally in relationship to the annual ovarian cycle of Calotes versicolor. Histological changes show distinct changes in various components of the infundibulum, uterus and vagina of the oviduct. The active phase in the oviduct cycle of C. versicolor is relatively long, extending from April to October. Histochemical results of the oviduct during the breeding season show PAS-positive glycosaminoglycans in the mucosal epithelium as well as the presence of hydroxysteroid dehydrogenases, esterase, and intense acid phosphatase activity in the uterine glands. Biochemically alkaline and acid phosphatase show marked cyclic changes in the infundibulum and uterus respectively during the oviduct cycle. Greater activity was observed during the breeding season. β-Glucuronidase, on the other hand, shows an inverse relationship with the oviduct cycle being most active during the regressive phase and least at the time of reproductive phase.
    Additional Material: 23 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992) 
    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
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 37-53 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The innervation of the musculature of the tongue and the hyobranchial apparatus of caecilians has long been assumed to be simple and to exhibit little interspecific variation. A study of 14 genera representing all six families of caecilians demonstrates that general patterns of innervations by the trigeminal, facial, glossopharyngeal, and vagus nerves are similar across taxa but that the composition of the “hypoglossal” nerve is highly variable. Probably in all caecilians, spinal nerves 1 and 2 contribute to the hypoglossal. In addition, in certain taxa, an “occipital,” the vagus, and/or spinal 3 appear to contribute fibers to the composition of the hypoglossal nerve. These patterns, the lengths of fusion of the contributing elements, and the branching patterns of the hypoglossal are assessed according to the currently accepted hypothesis of phylogenetic relationships of caecilians, and of amphibians. An hypothesis is proposed that limblessness and a simple tongue, with concomitant reduced complexity of innervation of muscles associated with limbs and the tongue, has released a constraint on pattern of innervation. As a consequence, a greater diversity and, in several taxa, greater complexity of neuroanatomical associations of nerve roots to form the hypoglossal are expressed.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 65-70 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The electron density of the lipid droplets and mitochondrial matrix of the interrenal cells of Rana perezi differs during the year. This makes it possible to characterize the different stages of interrenal cell activity. A droplet/mitochondria index, based on their relative size, may provide an indicator of cellular activity.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 71-85 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nereid polychaete, Platynereis dumerilii, possess two pairs of post-trochophoral eyes with one vitreous body each. The development of these eyes has first been observed in 2-day-old larvae. Whether the eye anlagen arise from stem cells or from undifferentiated ectodermal tissue was not determined. At first, the anlagen of the anterior and the posterior eyes adjoin each other. They separate in late 3-day-old larvae. The first separated eye complexes consist each of two supporting and two sensory cells. The supporting cells synthesize two different kinds of granules, the pigment granules of the pigment cup and the prospective tubules of the vitreous body. These tubules accumulate in the distal process of the supporting cell. The vitreous body is formed by compartments of the supporting cells filled with the osmiophilic vitreous body tubules. The short, bulbar photosensory processes bear microvilli that emerge into the ocular cavity. At the apex of each sensory cell process, a single cilium (or occasionally two) arises. The sensory cells contain a different kind of pigment granule within their necks at the level of the pigment cup. The rate of eye development and differentiation varies. New supporting cells are added to the rim of the eye cup. They contribute to the periphery of the vitreous body like onion skins, and sensory cells move between supporting cells. The older the individual compartments of the vitreous body are, the more densely packed is their content of vitreous body tubules. Elongation of the sensory and supporting cell processes of the older cells increases the volume of the eye. The eyespots of the trochophore are briefly described as of the two-celled rhabdomeric type with a single basal body with ciliary rootlet.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 141-154 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Movements of the neck, jaws, and hyolingual apparatus during inertial feeding in Caiman crocodilus were studied by cineradiography. Analysis reveals two kinds of cycles: inertial bites (reposition, kill/crush, and transport) and swallowing cycles. They differ in their gape profile and in displacement of the neck, cranium, and hyolingual apparatus.Inertial bites are initiated by an elevation of the neck and cranium; the head is then retracted backward, the prey simultaneously being lifted by the hyolingual apparatus. Next the lower jaw is depressed, and the prey is rapidly pushed further upward by the hyolingual apparatus. Thereafter fast mouth-closure occurs with the neck and cranium being abruptly depressed, the lower jaw elevated, and the hyolingual apparatus rapidly retracted ventrally. Depression of the neck and cranium thrusts the head forward and impacts the backward moving prey more posteriorly in the oral cavity.Swallowing cycles initially involve movement of the hyoid in front of the prey followed by rapid posteroventrad retraction of the hyoid, forcing the prey into the esophagus during opening and closing of the mouth. After mouth-closure, the hyoid apparatus is again protracted.Jaws, neck, tongue, and hyoid apparatus play an active role during intertial feeding sequences. At the beginning of a feeding sequence, the hyolingual apparatus mainly moves dorsoventrally, whereas toward the end of a sequence anteroposterior displacements of the hyoid are prominent. © 1992 Wiley-Liss, Inc.
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  • 13
    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 female reproductive tract and corpus luteum is examined in Sphenomorphus fragilis, a lizard from the lowland regions of New Guinea exhibiting incipient viviparity. Females oviposit eggs that hatch either immediately or within a few hours. Corpora lutea form from ovulated follicles and decrease in diameter as embryonic development progresses. The oviduct from vitellogenic females is sparsely populated with well developed uterine glands containing secretory granules. The eggs are covered with a relatively thin shell (10 μm thick) composed of an inner boundary layer and proteinacous fibers. The secreted shell is complete by early neurulation. Shell morphology does not change throughout the remainder of the in utero incubation period. A well vascularized uterus and chorioallantoic membrane provide simple placentation. These findings suggest that the reduction in shell thickness associated with the evolution of a placenta is due to a decrease in the number of shell glands in the uterus and is not a delay or inhibition of the shelling process per se. This hypothesis further suggests that the selective forces favoring shell gland loss act on the vitellogenic female during gland recruitment which occurs prior to ovulation and not on the pregnant female. © 1992 Wiley-Liss, Inc.
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 191-200 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Study of the esophageal microscopic morphology of adult Rana perezi by light and electron microscopy discloses some large folds throughout the esophagus that are in themselves ringed. Glandular ostia open in the furrows of the luminal surface. The esophageal wall is made up of a connective adventitia rich in melanocytes, a muscular tunica, a connective and glandular subepithelial layer, and a pseudostratified ciliated epithelium. This epithelium basically consists of ciliated, goblet, basal, microvillous-apex, and migratory cells. Two types of goblet cells are distinguished with regard to the granular ultrastructure. The microvillous-apex cell has not been found in other amphibians. It shows a very differentiated morphology with a high number of mitochondria. The basal cells give the epithelium a pseudostratified morphology, and they have a proliferative function. Glands are branched and drain through an excretory duct that has a monolayered mucosecreting epithelium. The glandular units are formed by two principal types of cells: mucosecretory and serous. © 1992 Wiley-Liss, Inc.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 281-290 
    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 Eurycea cirrigera are exocrine glands in the cloaca that secrete a substance that bathes sperm stored in the lumen after mating and prior to oviposition. Many sperm remain in the spermathecae after oviposition, and the spermathecal epithelium becomes spermiophagic. Pseudopodia enclose sperm into endocytic vacuoles. The vacuoles become associated with primary lysosomes in the cytoplasm. Following formation of secondary lysosomes and resulting condensation of the sperm fragments, residual bodies are exocytized into the surrounding connective tissue stroma. By the start of the next breeding cycle, most sperm remaining from the previous mating have been degraded, but some sperm remain in the lumen, and the viability of these sperm is unknown. © 1992 Wiley-Liss, Inc.
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  • 16
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Basement membranes (BMs) of vertebrates and invertebrates have been shown to contain glycoproteins and proteoglycans, which include oligosaccharides and glycosaminoglycans. Lectin binding sites were characterized in the BM of gastrulating embryos of the starfish, Pisaster ochraceus. In early and mid-gastrulae, the fluorescein isothiocyanate (FITC)-lectin conjugates of concanavalin A (Con A) and wheat germ agglutinin (WGA) reveal the presence of mannose/glucose and glucosamine/sialic acid residues in the BM of all regions of the embryos. However, in the late gastrula embryo, an apparent reduction of these components is observed over the esophageal BM. Ultrastructural studies using the lectin-gold conjugates Con A, Limax flavus agglutinin (LFA), specific for sialic acid, and Dolichos biflorus agglutinin (DBA), specific for galactosamine, demonstrate that most mannose/glucose and galactosamine containing residues lie in the lamina densa, whereas most sialic acid residues are located over the lamina lucida. In addition, a statistical analysis of lectin binding in the late gastrula embryo reveals that the amount of labelling with both Con A and LFA is significantly reduced in the esophageal region, suggesting that mannose/glucose and sialic acid residuces are reduced in this region. These results confirm the observations of the FITC-lectin studies described above. They also confirm earlier studies that demonstrated a difference in BM morphology of the esophageal region (Crawford, '88). Mesenchyme cells, some of which arise from the forming coeloms (Crawford, '90), and which may represent a distinct population, colonize exclusively on this esophageal BM, where they later differentiate into muscle. Quantitative differences in BM glycoconjugates may act to direct the presumptive muscle cells to the region of the esophagus. © 1992 Wiley-Liss, Inc.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 47-83 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A large sample of embryological material of the North American paddlefish Polyodon spathula (Acipenseriformes: Polyodontidae) confirms that early development in Polyodon is very similar to that reported for the sister group of Polyodontidae, the sturgeons (Acipenseridae). Polyodon illustrates many basic aspects of acipenseriform (and actinopterygian) head development that have not been adequately described. In this paper, we provide an overview of external features of cranial development using scanning electron microscopy. The observations are correlated with staging schemes previously proposed for paddlefishes and other acipenseriforms. Events that occur after the start of neurulation (stage 19) to the start of feeding (stage 46) are emphasized. New information on the structure and folding of the mandibular and hyoid segments permits an understanding of the early development of the pharyngeal region. In addition, we offer new descriptions of the hatching gland, the olfactory organ, the sensory barbel, and the initiation of paddle outgrowth. We also comment on the mode of origin of the hypophysis, and refute the notion that it is derived from the lips of the anterior neuropore as suggested in older literature. This information sets the stage for future comparative and experimental studies of the embryology of basal actinopterygians. © 1992 Wiley-Liss, Inc.
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  • 18
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 15-20 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The presence of seminal receptacula in the female reproductive tract of Opisthopatus cinctipes (Purcell, 1900) has been disputed (Choonoo, '47; Ruhberg, '85; Herzberg et al., '80). However, they do occur and are described here from observations by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). No spermatozoa are associated with the surface of the ovary; in contrast the ovary of Peripatopsis capensis is covered with spermatozoa and numerous small rounded cells. The seminal receptacula of O. cinctipes are formed from a loop in the proximal region of the uterus and contain remnants of spermatozoa in their lumens. The epithelial cells lining the seminal receptacula contain numerous vesicles and residual bodies. It is suggested that these cells absorb those spermatozoa not required for fertilization, and that the seminal receptacula in the Peripatopsidae act as short-term storage sites for spermatozoa. By contrast, the seminal receptacula of the Peripatidae are considered to act as long-term storage sites for spermatozoa. © 1992 Wiley-Liss, Inc.
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  • 19
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning and transmission electron microscopy of the antennae of Culicoides impunctatus and Culicoides nubeculosus show that males and females share five sensillum types. Sensilla chaetica resemble mechanoreceptors, each innervated by a single neurone whose dendrite terminates distally in a tubular body: the arrangement of sensilla on male antennae suggests that females are located by sound. The antennae have both sharp- and blunt-tipped sensilla trichodea, sharp-tipped sensilla on only the distal third and blunttipped sensilla on all subsegments. These sensilla are typical of olfactory receptors, having multiporous walls and being innervated by a number of neurones with bifurcating dendrites ascending the hair shafts. Sensilla basiconica occur on the distal five subsegments of the female antenna and the distal three subsegments of the male antenna. Sensilla coeloconica always occur on subsegment one and sometimes on a number of other subsegments, depending on sex and species. Both basiconic and coeloconic sensilla have double walls and unbranched dendrites and may be either olfactory or thermo- and/or hygroreceptors. All antennae except those of male C. impunctatus antennae have sensilla ampullacea, apparently deep-seated olfactory or thermoreceptors. Small peg sensilla fitting the description of contact chemoreceptors occur only at the tip of the male antenna. © 1992 Wiley-Liss, Inc.
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  • 20
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 159-169 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Monoclonal antibody (mAb) WE3 recognizes an antigen that is developmentally expressed in the wound epithelium during adult newt limb regeneration. Experiments were designed to determine whether retinoic acid (RA), dissolved in dimethyl sulfoxide (DMSO) and administered by intraperitoneal injection, would enhance the temporal appearance of the WE3 antigen. RA given on days 1 or 4 after amputation, when the WE3 antigen is not yet detectable, resulted in moderate reactivity to mAb 2 days after injection and strong reactivity throughout the wound epithelium 4 days after injection. DMSO alone had no enhancing effect. RA also caused limb skin epidermis to exhibit reactivity to mAb WE3, initially near the amputation level, but then also more proximally. By 4 and 6 days after RA injection, epidermis of the flank, eye lid, and unamputated hind limbs also became strongly reactive to mAb WE3. Outer layers of skin epidermis were shed, resulting in an epidermis only one or two cells thick. Epidermis of newts given DMSO alone remained non-reactive to mAb WE3. When RA was given on days 7 and 10 after amputation, when a low level of mAb WE3 reactivity is already present in the wound epithelium, a considerable enhancement of mAb WE3 reactivity occurred through the next few days. No such enhancement was seen with DMSO alone. RA also greatly increased mAb WE3 reactivity in the wound epithelium of denervated limbs, in which case the wound epithelial reactivity to mAb WE3 is normally low. Retinol palmitate also increased mAb WE3 reactivity. The results raise the possibility that the WE3 antigen is a component of most if not all retinoid target tissues in newts. © 1992 Wiley-Liss, Inc.
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  • 21
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 197-224 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mechanics of the skull of the pigeon are analyzed quantitatively, based on a three-dimensional kinematic computer model that considers the skull as a mechanism (Goodman, '60). The degrees of freedom at each cranial joint are defined and translated into geometric relations, using the method of Elshoud ('80). The model predicts the positions of cranial elements from three input variables: the positions of the upper and lower bills and the length of the M. protractor quadrati et pterygoidei. Simulations with the model suggest the presence of a locking mechanism for the lower bill, which prevents its depression. High speed films of feeding pigeons confirmed that locking can occur at different upper bill positions. The locking mechanism may permit feeding pigeons to use the elastic energy stored in the hinge of the upper bill during the grasp, producing simultaneous fast closing of the upper and lower bills. Simulation of jaw muscle activity suggests that these jaw muscles should not be divided into “openers” and “closers.” © 1992 Wiley-Liss, Inc.
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  • 22
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 287-294 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Neurons in whole mount preparations of the frontal ganglion (FG) of the cockroach, Periplaneta americana, were mapped with the aid of cobalt chloride staining and silver intensification techniques. Eighty-six neurons were counted in the FG after staining with reduced methylene blue. The cell size ranged between 20 to 35 μm in diameter. Of the somata located in the FG, 44 were found to contribute their fibers to the nervus recurrens, 26 to the right frontal commissure, 28 to the left frontal commissure, and 6 to the nervus connectivus. In addition, a few neurons presumably from the tritocerebral region also contribute their fibers in the formation of nervus connectivus. The present study has helped delineate the neuronal connections of the FG with the brain and neuroendocrine system (corpora cardiaca and corpora allata). This information will be useful in facilitating the positioning of microelectrodes in our future electrophysiological experiments. © 1992 Wiley-Liss, Inc.
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  • 23
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    Journal of Morphology 213 (1992), S. 335-340 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microcorrosion casts of the renal vascular system of tadpoles of the Clawed Frog, Xenopus laevis, were observed by scanning electron microscopy. Glomerular differentiation was studied qualitatively and quantitatively during developmental stages 56-66 (metamorphic climax). The general structure of the renal vascular system corresponds to the pattern commonly found in anurans; however, the arterial supply has conspicuous connecting vessels that supply groups of glomeruli. In the dorsal part of the kidney, qualitative differentiation of glomerular structures precedes quantitative growth. The ventral part of the kidney has larger, well-developed renal corpuscles of nearly adult appearance. Four developmental stages of glomerulogenesis are distinguished morphologically and their glomerular and vascular growth is analyzed. © 1992 Wiley-Liss, Inc.
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  • 24
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 25
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    Journal of Morphology 214 (1992), S. 1-41 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Postembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared-and-stained whole-mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46-65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that the timing, but not the sequence, of skeletal development in X. laevis is more variable than previously reported and poorly correlated with the development of external morphology. Examination of chondrocranial development indicates that the rostral cartilages of X. laevis are homologous with the suprarostral cartilages of non-pipoid anurans, and suggests that the peculiar chondrocranium of this taxon is derived from a more generalized pattern typical of non-pipoid frogs. Derived features of skeletal development not previously reported for X. laevis include (1) bipartite formation of the palatoquadrate; (2) precocious formation of the adult mandible; (3) origin of the angulosplenial from two centers of ossification; (4) complete erosion of the orbital cartilage during the later stages of metamorphosis; (5) development of the sphenethmoid as a membrane, rather than an endochondral bone; and (6) a pattern of timing of ossification that more closely coincides with that of the pelobatid frog Spea than that recorded for neobatrachian species. © 1992 Wiley-Liss, Inc.
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  • 26
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    Journal of Morphology 213 (1992), S. 349-364 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The central nervous system of Ixodes scapularis is fused into a single compact synganglion. The esophagus runs through the synganglion and divides it into supraesophageal and subesophageal parts. The supraesophageal portion contains a single protocerebrum with four pairs of glomeruli, paired optic lobes and cheliceral ganglia, and a single stomodeal bridge. The subesophageal portion contains a centrally located network of commissures and connectives, a pair of palpal ganglia, paired olfactory lobes of the first pedal ganglia, four pairs of pedal ganglia, and a single opisthosomal ganglion. A retrocerebral organ complex (ROC) in close vicinity of the digestive tract, as described in some other tick species, apparently is lacking. Perhaps the function of the ROC is performed by the paired, large, ganglion-like bodies that lie anterolaterad to the cheliceral ganglia.The rind, which is formed from the neuronal somata and glial cells, surrounds the central fibrous core or neuropile. Neurosecretory cells (NSC) are distinct among rind cells due to their large size and concentration of cytoplasmic neurosecretions. NSC are present throughout the synganglion, although the subesophageal portion contains larger groups of these cells. Histological serial sections, stained with Meola's (Trans Am Microsc Soc 89:66-71, '70) paraldehyde fuchsin (PAF) procedure revealed 24 PAF-stained, putative neurosecretory regions in the synganglion of virgin, unfed females. All of these regions appear to be connected and associated with the nearest ganglion and are correspondingly named. Eighteen PAF-positive regions occur in the synganglion. In addition, PAF-negative (green-stained) cells occupy 6 distinct regions in the synganglion of unfed, unmated females. © 1992 Wiley-Liss, Inc.
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  • 27
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    Journal of Morphology 214 (1992), S. 43-48 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Female Thamnophis sirtalis were administered intraperitoneal implants of either estradiol 17β (E2), testosterone (T), 5α-dihydrotestosterone (DHT), or empty silastic capsules for 3 weeks. Plasma levels of E2 and T, measured by specific radioimmunoassay, were significantly elevated in E2 and T-implanted females when compared to controls. T-implanted females did not have elevated circulating E2 levels, suggesting that E2 in the plasma normally is not derived from peripheral conversion of T to E2. Implantation of DHT did not significantly change circulating levels of E2, T, or DHT. All three sex steroid - treated groups of animals had increased oviductal mass compared to controls, while hepatic mass of only E2-treated animals was significantly greater. None of the steroid treatments influenced ovarian mass. Oviductal epithelial cell height and area were greater in the three steroid-treated groups. Testosterone increased myometrial area while DHT drastically altered oviductal morphology. Hepatic cell area and number increased significantly in E2-treated females. However, a small increase in both hepatic cell area and number was noted in T- and DHT-treated females as well. These results suggest that androgen in both an aromatizable and non-aromatizable form can affect the oviduct of females but that the liver primarily responds to estrogenic steroids. © 1992 Wiley-Liss, Inc.
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  • 28
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    Journal of Morphology 214 (1992), S. 333-340 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The labial palpus of the elephant louse Haematomyzus elephantis has six sensilla that represent three different types: trichoid, basiconic, and styloconic. Two rows of basiconic sensilla are situated on the dorsal and ventral surfaces of the rostrum, and each row consists of three sensilla. Male and female antennae have 15-17 trichoid sensilla situated on the scape, pedicel, and three antennal annuli. Both sexes have two sensilla basiconica on the dorsal surface of the pedicel near the junction of the scape and pedicel. Two coeloconic (tuft) sensilla are situated on the antennae of both sexes, one sensillum on each of the last two annuli. There are three plate organs, two on the last annulus and one on the penultimate annulus of the male and female antennae. Sexual dimorphism is exhibited in the male and female antennae, in that the male has about twice as many sensilla basiconica on the apex of the last annulus as does the female. The total number of sensilla basiconica on the apex of the male antennae is at least two times the number that is known to be present in any other species of lice. © 1992 Wiley-Liss, Inc.
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  • 29
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    Journal of Morphology 214 (1992), S. 341-350 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Representative functional teeth from Cryptobranchus alleghaniensis (Cryptobranchidae), Amphiuma means (Amphiumidae), Dicamptodon ensatus (Dicamptodontidae), Necturus maculosus (Proteidae), and Dermophis sp. (Costa Rica) (Caeciliidae) were prepared for transmission electron microscope and electron microprobe analysis of the trace elements of the enamel layer. The enamel layer of these species is very thin and the arrangement of enamel crystals variable. In particular, the outer part of the enamel layer in which hydroxyapatite elements (Ca, P) and trace elements (e.g., F, Fe, Mg) are concentrated, is most heavily mineralized. The concentrations and alignment of crystals in the outer and inner parts of the enamel layer differ among these species.The presence of collagen fibers in the inner part of the enamel layer of Cryptobranchus and Dermophis indicates that it is enameloid rather than true enamel. The presence of trace elements may be related to the pattern of mineralization of enamel or enameloid, as suggested for tetra-odontiform fishes by Suga et al. (J. Dent. Res. 68:1115-1123, 1989). © 1992 Wiley-Liss, Inc.
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  • 30
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    Journal of Morphology 214 (1992), S. 357-374 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A statistical and functional relationship between neural canal anatomy and locomotor mode is demonstrated in living marine mammals of the Order Carnivora. This relationship is interpreted to be the result of differential innervation and territory of musculature involved in generating the six locomotor patterns analyzed. This osteological reflection of a behavioral trait allows prediction of locomotor pattern in extinct genera of closely related taxa. The robust data allow such predictions even when a considerable number of presacral vertebrae are missing in the fossil specimens. In some cases, these predictions conflict with interpretations based solely on limb osteology. © 1992 Wiley-Liss, Inc.
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  • 31
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    Journal of Morphology 211 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 32
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    Journal of Morphology 211 (1992), S. 1-6 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oosorption has been considered an important strategy in many invertebrate species which occurs in response to behavioral, ecological, or physiological factors. In crustaceans, the early light microscopic studies of the ovary attributed a role in oosorption to follicle cells, hemocytes, or phagocytes. In this study, ovaries were collected from female golden crabs following spawning and processed for examination by electron microscopy.Following spawning, several unspawned oocytes which had become dissociated from their follicle cells were found in the ovaries. They appeared to be lodged within the lumen. Such oocytes were observed undergoing various stages of autolysis. At no time were hemocytes or recognizable phagocytes found in the lumen of the ovaries or in contact with the degenerating oocytes. Follicle cells which had surrounded the oocytes prior to the time of spawning exhibited disrupted membranes. Resorption of unspawned eggs appears to occur by autolysis of the individual oocytes.Several of the females who had recently spawned had numerous sperm in their ovaries. Such sperm may have been pressed into the lumen at the time of spawning or during the fixation process.
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  • 33
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    Journal of Morphology 211 (1992), S. 41-54 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light and transmission electron microscopy of the liver of juvenile Atlantic salmon (Salmo salar) reveals a tubular arrangement of parenchymal cells, with biliary passages typically located at the center of tubules. Hepatocytes generally contain a single nucleus surrounded by a cuff of rough endoplasmic reticulum (RER), with many round to elongate mitochondria associated with the perinuclear RER. Whereas glycogen deposits are common and usually lie at the cell periphery, parenchymal cells seldom contain lipid droplets. Golgi complexes and heterogeneous dense bodies also occur in many hepatocytes, often in close proximity to bile canaliculi. Numerous microvilli from hepatocytes extend into the subendothelial space of Disse, which is also the location of stellate fat-storing cells. Interhepatocytic macrophages, sometimes containing prominent phagolysosomes and residual bodies, are common in the liver. The intrahepatic biliary system consists of intercellular canaliculi, bile pre-ductules, ductules, and ducts. In contrast to some other teleosts, the liver of the Atlantic salmon contains no intracellular bile canaliculi or Kupffer cells. The hepatic endothelium, arterioles, and perivenous regions are also described.
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  • 34
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    Journal of Morphology 211 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 35
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    Journal of Morphology 211 (1992), S. 137-146 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The small didelphid cmarsupial, Monodelphis domestica, uses a lateral sequence walk during slow treadmill locomotion and gradually shifts to a trot as speed increases. At higher speeds it changes abruptly to a half-bound. Cinematographic records suggest significant lateral bending but no sagittal bending of the trunk during the slow walk and a reduced amount of lateral bending during the fast walk. There is slight lteral, but no sagittal, bending during the trot. Sagittal bending is obvious during the half-bound, but no lateral bending is evident. Cineradiography confirms that the vertebral column of the trunk bends laterally during the slow walk. Bending occurs throughout the trunk region, but seems to be most pronounced in the anterior lumbar region. Associated with this bending of the trunk is substantial rotation of the pelvic girdle in the plane of yaw. Pelvic rotation is synchronized with the locomotor cycle of hindlimbs. Each side of the pelvis rotates forward during the recovery phase of the ipsilateral hindlimb and backward during the contact phase of this limb. Information on locomotor trunk movements in other limbed tetrapods is limited. The pattern of trunk bending found in Monodelphis, however, is consistent with that reported in the placental mammal Felis catus and in some lepidosaurian reptiles. This suggests that sagittal bending did not replace lateral bending during the evolution of mammals, as is sometimes suggested. Rather, bending in the vertical plane seems to have been added to lateral bleeding when the ancestors of extant mammals acquired galloping and bounding capabilities.
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  • 36
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    Journal of Morphology 211 (1992), S. 125-135 
    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 shows that lingual papillae occur all over the dorsal surface of the tongue of the freshwater turtle, Geoclemys reevesii. The surface of each papilla is composed of compactly distributed hemispherical bulges, each composed of a single cell. Microvilli are widely distributed over the surface of cells. Histological examination reveals that the connective tissue penetrates deep into the center of papillae and that the epithelium is stratified columnar. Under the transmission electron microscope, the cells of the basal and the deep intermediate layers of the epithelium appear rounded. A large nucleus lies in the central area of each cell. The cytoplasm contains mitochondria, endoplasmic reticulum and free ribosomes. The cell membrane form numerous processes. The shallow intermediate layer contains two types of cell. The cytoplasm of the first has numerous fine granules, in addition to mitochondria, ribosomes, and endoplasmic reticulum. The other type of cell contains highly electron-dense granules. The surface layer shows two cell types. One type consists of typical mucous cells. The other type of cell contains fine, electron-lucent granules. The latter cells lie on the free-surface side, covering the mucous cells, and have microvilli on their free surfaces.
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  • 37
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    Journal of Morphology 211 (1992), S. 165-178 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The eyelids of the newt were studied in 10 μm serial paraffin and 1-2 μm plastic sections using standard histological stains and special stains for glycconjugates. The eylids contain four different glands. Simple acinar serous and simple acinar mucous glands occur in the skin; unicellular mucous glands occur in the conjunctiva; and convoluted tubular seromucous glands are present in connective tissue beneath the conjunctiva. The first two are identical to cutaneous glands found elsewhere on the head and body. The simple acinar serous glands are surrounded by myoepithelial cells and release their sectetion, which is composed largely of proteins with minimal glycoconjugate content, by a holocrine mechansm. The secretory product of the simple acinar mucous glands is composed of neutral glycoconjugates with a minor content of acidic glycoconjugates; the mucin exhibits strong PAS and PAPD staining and weak staining by AB and PAPS methods. The unicellular conjunctival mucous glands secrete both neutral and acidic glycoconjugates as shown by positive reactions with PAS, PAPD, PAPS, and AB methods. Convoluted tubular seromucous glands in the ventral eyelid synthesize both proteins and neutral glycoconjugates. The mucous secretions of the conjunctival glands probably provide lubrication and protection for the cornea.
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  • 38
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: In the absence of silicate in the growth medium, Netzelia tuberculata cells withdraw their feeding lobopodia, become quiescent, and cease to divide. Upon replenishment of silicate, growth resumes within 18-24 hours. Cytoplasmic changes produced by a low silicate medium result in a zonal arrangement, with siliceous particles at the outer periphery of the cytoplasm in a region rich in Golgi bodies (Region A), a more centrally located layer containing endoplasmic reticulum, lipid reserves, and finely granular cytoplasm (Region B), and a region of partially digested food and waste material fringed by fine rhizopodia extending into the central space of the test (Region C). The reserve siliceous particles in the outer peripheral cytoplasm are foreign particles that contain a fragile deposit of silica and appear to be incomplet. This may be a mechanism for conserving silica in the low-silicate medium by coating particles instead of making particles of solid silica de novo. Upon addition of silicate to the growth medium, new siliceous particles are synthesized within vacuoles in the region of the Golgi apparatus within 2-18 hours. Vacuoles containing fine silica deposits, characteristic of new particle production, are surrounded by Golgi-derived vesicles previously shown to be a source of membrane for the silica-secreting vacuoles. The newly synthesized particles are solid silica as is characteristic of de novo secreted test particles, in contrast to the numerous silica-coated foreign bodies found in quiescent cells produced in low-silicate medium.
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  • 39
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    Journal of Morphology 212 (1992), S. 1-11 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An electron microscopic study of the differentiation of pyriform cells and their contribution to oocyte growth in three lizards (Tarentola mauritanica, Cordylus wittifer, Platysaurus intermedius) and one colubrid snake (Coluber viridiflavus) revealed that pyriform cells differentiate from small follicle cells via intermediate cells after establishing an intercellular bridge with the oocyte (see also Hubert: Bull Soc Zool Fr 102:151-158, 1977; Filosa et al: J Embryol Exp Morphol 54:5-15 1979; Klosterman: J Morphol 192:125-144, 1987). Once differentiated, pyriform cells display ultrastructural features indicative of synthetic activity, including abundant ribosomes, Golgi membranes, vacuoles, mitochondria, and lipid droplets. These cellular components extend to the apex of the cell at the level of the intercellular bridge, suggesting that constituents of pyriform cells may be transferred to the oocyte. Furthermore, we demonstrate for the first time that pyriform cells incorporate exogenous yolk. The yolk is segregated inside maturing yolk granules that form in the pyriform cell in the same manner as described for vitellogenic oocytes in non-mammalian vertebrates (see Wallace: Developmental Biology, A Comprehensive Synthesis 127-177, 1985). It is the first clear evidence that pyriform cells and the oocyte may fulfill similar vitellogenic functions. The establishment of an intercellular bridge may represent a crucial event in the development of an integrated system in which pyriform cells and oocyte cooperate.
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  • 40
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Parthenogenetic populations of the gecko Lepidodactylus lugubris are widespread throughout Polynesia. They often occur parapatrically, and occasionally syntopically, with the increasingly rare bisexual populations. In these instances, a small number of hybrid individuals occur and include both “female” and “male” external phenotypes, both with greatly reduced gonads.Histological examination demonstrates that these hybrids possess small ovotestes. The differentiation of the cortical tissue is identical in both “male” and “female” hybrids, but the medullary tissue is more developed in “males.” The remainder of the genital tract in “females” resembles that of fertile females in the parthenogenetic and bisexual populations. By contrast, the “male” hybrids are markedly intersexual. In one of the two specimens autopsied, the hemipenes are more or less the same size as those of bisexual males, and the sexual segment of the kidney is hypertrophied and serous. In the other hybrid “male,” the hemipenes have a structure similar to that seen in females, and the sexual segment of the kidney is poorly differentiated. In both hybrid “males,” the ductus deferens is extremely narrow and further reduced in its middle portion; oviducts are present and resemble those of normal or hybrid females.Thus, embryonic-like gonads are associated with complete and normal female reproductive ducts in hybrid “females.” Hybrid “males” also have embryonic-like gonads and feminized genital ducts but associated with secondary sexual characters that match those of sexually active or quiescent normal males.
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  • 41
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    Journal of Morphology 212 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 42
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    Journal of Morphology 212 (1992), S. 99-107 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sacculus of Oreochromis niloticus is anatomically separated from the utriculus and semicircular canals. The saccular wall is composed of the sensory epithelium, transitional epithelia, and squamous epithelium. Cellular granules are abundant in the sensory and transitional epithelia but scarce in the squamous epithelium. Over the dorsal side of the dorsal transitional epithelium there exists an oval patch of cells with distinctive microvilli. New finding is a shallow groove which extends from the anterior end of the sensory epithelium approximately halfway down along the ventral perimacular transitional epithelium. Small vesicles, which appear “empty” under transmission electron microscopy (TEM), are aggregated in the posterior region of the groove. These small vesicles are also present in both the sensory and transitional epithelia. A second kind of vesicle is comparatively large and appears filled with stainable contents. These vesicles are restricted to the sensory region. Both kinds of vesicles appear to be involved in apical secretion and possibly provide the otolithic membrane with fibers. The otolithic membrane is composed of a gelatinuous layer and subcupular meshwork. The meshwork appears to contribute to the formation of the otolith. The small empty vesicles appear to originate in sensory and transitional epithelial cells and may form the subcupular meshwork. The larger filled vesicles are derived predominantly from sensory cells in the sensory epithelium and appear to contribute to the gelatinuous layer of otoliths. © 1992 Wiley-Liss, Inc.
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  • 43
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    Journal of Morphology 212 (1992), S. A1 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 44
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The liver of the cobia, Rachycentron canadum, was examined by gross dissection, histological, and ultrastructural procedures. Other visceral organs were examined by histological techniques only. Unique perivenous smooth muscle cords are associated with veins in these systems, but they are particularly prominent in their association with the hepatic portal veins and their numerous intrahepatic branches. The perivenous smooth muscle cords accompany tributaries of the portal veins to the junction of the venules with the hepatic sinusoids. The reciprocal contraction and relaxation of various segments of the smooth muscle cords appear to result in pooling of blood in temporary reservoirs and in its transport to various regions of the organ. This process might apply to other organ systems as well. Possibly this unique relationship of the smooth muscle cords with veins functions in a diving reflex. Triads are occasionally encountered in the cobia liver. © 1992 Wiley-Liss, Inc.
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  • 45
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    Journal of Morphology 212 (1992), S. 201-211 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Semi-thin plastic sections reveal that the carotid baroreceptor region in the rock hyrax comprising the origin of the internal carotid artery has a preponderantly elastic structure and a thick tunica adventitia. In contrast, the common carotid artery has a musculoelastic structure, whereas the cranial segment of the internal carotid artery (immediately distal to the baroreceptor areas) shows the features of a muscular artery. Electron microscopy discloses the presence of sensory nerve endings within the parts of the tunica adventitia adjoining the preponderantly elastic zone of the internal carotid artery. These nerve endings are characterized by varicose regions containing a large quantity of mitochondria. Bundles of collagen fibers in the tunica adventitia form convolutions or whorls around the nerve terminals and often terminate on the surface of the elastic fibers or into the basement membranes of the neuronal profiles. The large content of elastic tissue in the tunica media of the baroreceptor region may render the vessel wall highly distensible to intraluminal pressure changes. This, in turn, would facilitate the transmission of the stimulus intensity to the sensory nerve terminals located in the tunica adventitia. It is suggested that the stretching of elastic fibers may form the main mechanical event leading to the distortion of the associated nerve terminals. However, a change in the geometrical configuration of the bundles of collagen under the influence of the elastic fibers may provide a better insight into the mechanisms of distortion of the baroreceptors related to and/or in contact with collagen fibers. © 1992 Wiley-Liss, Inc.
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  • 46
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    Journal of Morphology 212 (1992), S. 269-280 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two of the forearm flexors of the horse, the superficial and deep digital flexor muscles, are critical to support the digital and fetlock joints, exhibit differing insertions, and are passively supported by the proximal and distal check ligaments, respectively. These two muscles differ in histochemical composition and architecture. The differences are correlated with the different stress levels transmitted through their tendons, and the different frequencies of clinical breakdown that have been reported. Both muscles contain type I and type IIa fibers. A few type IIb fibers occurred in the deep digital flexor. The superficial digital flexor contained approximately 56% type I fibers, extremely short muscle fibers, and extensive connective tissue investment. In contrast, the deep digital flexor had three muscle heads: ulnar, radial, and “long” and “short” regions of the humeral head. The “long” and “short” regions of the humeral head contained 33% and 44% type I fibers, respectively, fiber lengths three to four times as long as those in the superficial digital flexor, and relatively less connective tissue investment. Flexor carpi radialis and flexor carpi ulnaris compared most closely with the humeral head of the deep digital flexor. These data suggest a correlation of the unique architecture of superficial digital flexor with its proposed elastic storage properties during locomotion in horses, and an explanation for the frequent breakdown of the superficial digital flexor in athletic horses. © 1992 Wiley-Liss, Inc.
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  • 47
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The feline anterior sartorius is a long strap-like muscle composed of short muscle fibers. Nerve branches that enter this muscle contain the axons of motor units whose constituent muscle fibers are distributed asymmetrically within the muscle. In the present study, twitch and tetanic isometric contractions were evoked by stimulating individual nerve branches while muscle force was recorded and intramuscular length changes were monitored optically by the movement of reflective markers on the muscle. Contractions elicited by stimulating the parent nerve produced little change in the positions of the surface markers. Contractions elicited by stimulating the proximally or distally directed nerve branches caused the muscle to shorten at the end closest to the nerve branch and lengthen at the opposite end. Some muscles were supplied by a centrally directed nerve branch whose stimulation produced variable effects: in some cases a portion of the muscle shortened whereas the rest lengthened, but in other cases, the positions of the surface markers showed little change. The intramuscular length changes produced by stimulating single nerve branches were greater during isometric contractions at short whole-muscle lengths than at long whole-muscle lengths. The twitch and tetanic length-tension relationships obtained by stimulating the individual nerve branches were not congruent with the length-tension relationship produced when the parent nerve was stimulated. At short whole-muscle lengths, stimulation of a single nerve branch generated only a small fraction of the force that could be generated by the muscle when the parent nerve was stimulated. As whole-muscle length increased, an increased fraction of total muscle force could be generated by stimulating a single nerve branch. The results suggest that a complex relationship between passive and active elements contributes to the total muscle force and depends on the distribution of active and passive muscle units throughout the muscle. © 1992 Wiley-Liss, Inc.
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  • 48
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    Journal of Morphology 213 (1992), S. 241-250 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The heterocellular female gonad of the typhloplanoid Castrada viridis consists of a single germarium and two rows of vitellaria. The germarium, composed of a germinative zone and a growth zone, is surrounded externally by a layer of accessory cells the function of which is hypothesized in this study. The main feature of oocyte differentiation is the synthesis of small electron-dense inclusions produced by the rough endoplasmic reticulum (R.E.R.) and Golgi complex. The electron-dense content of the egg inclusions reacts positively to the cytochemical test used to detect polyphenols and is only partially extracted following incubation in protease. The genesis, composition, and peripheral location of egg inclusions in mature oocytes suggest that they could represent residual eggshell granules. The presumed function of eggshell granules is discussed and their fine morphology is compared with that observed in other neoophoran Platyhelminthes. © 1992 Wiley-Liss, Inc.
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  • 49
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    Journal of Morphology 213 (1992), S. 251-263 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron microscopy has been used to enhance the description of a single species, Caretta caretta (the loggerhead turtle), staged according to Miller's system for the development of marine turtles. Incubation over a temperature range of 25°-34°C confirms previous observations that, under artificial conditions and at a constant incubation temperature, normal development is confined to a limited temperature range. Premature pipping is a feature of incubation at the lower end of this range; abnormal development, generated during the first third of the incubation period, occurs just above the normal range. Details of the external morphology of embryos from Miller stage 14 through to 25 are given together with an account of the developmental abnormalities produced at a high temperature of incubation. The data obtained confirm that Miller's scheme is generally applicable to C. caretta, provided that due regard is paid to the incubation temperature. © 1992 Wiley-Liss, Inc.
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  • 50
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    Journal of Morphology 213 (1992), S. 275-286 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographical (EMG) activity was recorded bilaterally from the masseter and temporalis muscles of alert ferrets (Mustela putorius furo) during mastication and crushing. Electromyographic activity was also recorded during biting while a bite-force transducer placed between the carnassial teeth registered forces ranging from 1.5 to 48.8 N. Linear regression analysis demonstrates that temporalis and masseter EMG activity are linearly related to bite force. Electromyographic activity from the balancing-side muscles is nearly equal to EMG activity of the working-side muscles during bone crushing with the carnassial teeth. It is hypothesized that a high percentage of balancing-side muscle activity in ferrets can be recruited during carnassial biting because the postglenoid process prevents ventral displacement of the working-side mandibular condyle. © 1992 Wiley-Liss, Inc.
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  • 51
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The sporogenesis of the microsporidium Abelspora portucalensis was studied with electron microscopy. In qualitative terms, new aspects of the cytoplasmic ultrastructure of the schizont, sporont, and sporoblast are described: the presence of microtubules, of aggregates of small opaque vesicles, and of dispersed larger vesicles with clear matrix. The hypothesis that the opaque vesicles may represent the Golgi apparatus and the clear vesicles may correspond to the smooth endoplasmic reticulum is discussed. The use of standard stereological and statistical techniques gives us a new perspective on the development of this microsporidium. The most relevant quantitative data display that the amount of rough endoplasmic reticulum (either in relative or absolute terms) presents significant differences among the three stages, with the sporont showing the highest values; that the absolute (but not the relative) volume of the large vesicles significantly changes during sporogenesis with the highest values presented by the sporont; that the surface-to-volume ratio of the schizont and sporont cells is similar and significantly greater than that of the sporoblast cell; that the surface density of the nucleus in relation to soma remains constant in the three stages (on the contrary, the surface-to-volume ratio of the nucleus increases and its volumetric density diminishes); and finally, that the nucleolus decreases its relative and absolute volumes. The functional significance of these results is analyzed and the application of similar methodology in quantifying the effects of drugs upon microsporidia is suggested. © 1992 Wiley-Liss, Inc.
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  • 52
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    Journal of Morphology 213 (1992), S. 341-347 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From electron micrographs we determined the ratio of mitochondrial to myofibril cross sectional area in cells of the first leg anterior depressor muscles of adult females of four spider species, each from a different genus. Species with more active web-monitoring tactics and greater tracheal supplies to their first legs have muscle cells that are better supplied with mitochondria than those with less active tactics and less well-developed tracheal systems. These results demonstrate that, even in homologous tissues of closely related species, mitochondrial supply can change to accommodate changes in metabolic activity. © 1992 Wiley-Liss, Inc.
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  • 53
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    Journal of Morphology 213 (1992), S. 365-393 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A comparative morphological study of nephromixial systems in three Californian terebellid polchaetes currently assigned to the genus Pista shows that P. fimbriata has all attributes of the generic type, but that P. pacifica and P. elongata differ markedly. The features of typical Pista include (among others): two pairs of usually unequal branchiae, long-handled anterior uncini (hooks) of crested avicular (bird-head-like) from, muddy, unornamented tubes, one pair of anterior excretory nephromixia (ENMX), and two pairs of separate thoracic reproductive nephromixia (RNMX) with genital papillae on segments VI and VII. A review indicates that P. fimbriata shares these typical features with practically all adequately described Pista species. However, P. pacifica and P. elongata possess three pairs of branchiae, long-handled uncini of distinctive crochet-like form, and membranous tubes with apertural hoods. Both have two pairs of ENMX, the first supplied by one pair of ciliated renal funnels, the second by two pairs of such funnels. But they differ in their RNMX: P. pacifica has three pairs of complex RNMX, those on each side united by a common duct. P. elongata has 11-13 pairs of simple RNMX united by common ducts. Although these species do not fit into Pista, no genus has been found to accommodate them. Generic placement is complicated by the fact that no instances of intra-generic nephromixial variation have been reported in the Terebellidae, although inter-generic variation is well known. If they are congeneric, this would be the first example of intrageneric RNMX variation in Terebellidae. But if assigned to separate genera or subgenera on the basis of their RNMX, their similarity of anterior uncini might be attributable to parallel or convergent adaptation to life in comparable tubes. More evidence, including molecular analysis, is needed for phylogenetic studies of Terebellidae. © 1992 Wiley-Liss, Inc.
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  • 54
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Compared to acoustically unspecialized mammals (soricids and murids), the middle ear of subterranean insectivores and rodents (twelve species of six families examined) was clearly distinguished and characterized by many common features: rather round and relatively larger eardrum without a pars flaccida; reduced gonial; loose or no connection between the malleus and the tympanic bone; reduced and straightened transversal part of the malleus; enlarged incus; increased and rather flat incudo-mallear joint; rather parallel position of the mallear manubrium and incudal crus longum in some species (and their fusion in abthyergids); reduced or even missing middle ear muscles. Convergent occurrence of these structural features in taxa of different origin and their generally derived character suggest that they cannot be categorized as degenerative. The form of the stapes can be considered as a non-adaptive trait; it was taxon specific yet remarkably polymorphous in some species and exhibited no convergent features among subterranean mammals. Structural retrogression resulting in a columella-like stapes was observed in some species lacking the stapedial artery. The stapedial base was relatively larger than in unspecialized mammals. The subterranean mammals did not exhibit conspicuously enlarged eardrums as would be required for sensitive tuning to low frequencies. It is, however, argued that while selective pressures in the subterranean ecotope promoted hearing of low frequencies, hearing sensitivity did not have to be enhanced. © 1992 Wiley-Liss, Inc.
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  • 55
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    Journal of Morphology 214 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 56
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of the sensory epithelia of the sacculus in two species of hake, Merluccius capensis and M. paradoxus, was analyzed by scanning electron microscopy (SEM). The sensory epithelia have two morphological features that are very different from other gadiform species. These include the presence of two large areas which are only linked by a narrow neck, and the larger proportion of hair cells oriented in the rostrocaudal axis than in other species. The deeper-dwelling species, M. paradoxus, has a larger proportion of hair cell with short ciliary bundles than does the shallower-dwelling species, M. capensis. These morphological specializations could improve the acoustic diserimination and localization capabilities of these species, possibly related to an increase in sensitivity to higher frequency sounds in the deeper-dwelling species. © 1992 Wiley-Liss, Inc.
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  • 57
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Ovarian follicular dynamics and fluctuations in fat body, oviducal, and liver masses were studied in captive Rana cyanophlyctis in comparison with wild-caught frogs, sampled at monthly intervals over a period of 12 months. In both the captive and wil-dcaught frogs first growth phase (FGP) and second growth phase (SGP) or vitellogenic oocytes were produced throughout the period examined; however, changes in ovarian and oviducal weights were less marked in the former group.In the captive frogs SGP oocyte production was reduced by 50%, and, maximum ovarian weight and SGP oocyte number were attained 2-3 months earlier than in wild-caught controls. The FGP oocyte pool in laboratory-maintained frogs, however was comparable with that of the corresponding wild-caught frogs. Captivity caused a threefold increase in atresia and reduced the number of oocytes reaching SGP. The depletion of fat stores in fat bodies during the later phases of captivity suggests that the deposition of lipids into oocytes (for SGP) was given priority over storage in the fat bodies.The low oviducal weights of captive frogs was correlated with a reduced number of SGP oocytes, which are the source of estrogen. On the other hand, liver weight remained high, indicating adequate hepatic vitellogenin synthesis. Possible reduction in its output was not detected, possibly due to the reduced number of follicles reaching SGP. The findings indicate that stress of captivity decreases gonadotrophins and estrogen levels. Oviducal growth is reduced in captive frogs. It is hypothesized that in the frog oviducts respond to estrogen in a threshold-dependent manner, whereas the liver responds to it in relation to the length of exposure. © 1992 Wiley-Liss, Inc.
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  • 58
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    Journal of Morphology 214 (1992), S. 153-158 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Epididymal sperm from the painted turtle (Chrysemys picta) possess a cytoplasmic droplet which is located eccentrically on the sperm midpiece. The droplet contains a large quantity of lipid droplets in addition to hollow vesicles and degenerate mitochondrial fragments. Lipid droplets are closely associated with mitochondrial membranes and may function in the formation or degradation of mitochondria. Cytoplasmic droplets become detached from the sperm midpiece in a coordinated manner shortly before the commencement of fall mating and are not observed on sperm recovered from the oviduct of females. © 1992 Wiley-Liss, Inc.
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  • 59
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    Journal of Morphology 214 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 60
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    Journal of Morphology 214 (1992), S. 261-267 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spirally arranged bundles of sub-endothelial smooth muscle enfold the small to medium-sized submucosal veins in the equine ileocecal junction. The muscle bundles, accompanied by the endothelial lining, bulge into the lumen of the vessels, partly occluding the latter. Transmission electron microscopy of the muscle cells reveals features consistent with vascular smooth muscle ultrastructure. It is proposed that the throttling effect of the muscle bundles causes engorgement of the submucosal venous plexus, which then assists in the closing of the ileocecal orifice. © 1992 Wiley-Liss, Inc.
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  • 61
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The skin of the amphibious fishes, Periophthalmus cantonensis and Boleophthalmus pectinirostris, was investigated by transmission electron microscopy (TEM). In both species the epidermis consists of superficial nonvacuolated epithelial cells, swollen epithelial cells with membrane limited cytoplasmic vacuoles, and basal epithelial cells in a single layer. Unicellular mucous glands, but no chloride cells are found in the epidermis of B. pectinirostris; in contrast there are chloride cells and no unicellular mucous cells in P. cantonensis. Intraepidermal blood vessels are a notable feature in the epidermis of P. cantonensis. Capillaries are distributed near the epidermal surface, offering an air-blood barrier of sufficient thinness (2-4 μm) for cutaneous respiration. The large blood vessels (arterioles and venules) are seen in the middle stratum of the epidermis and seem to be able to regulate blood flow in the skin. In B. pectinirostris, the dermal capillaries lie immediately below the superficial epithelial cells at the apex of a dermal bulge where the air-blood barrier is almost as thin as that of P. cantonensis despite locally different histology. In the spacious dermal bulges, the dermal tissue such as blood vessels, pigment cells, fibroblasts, and collagen fibers are scattered. Melanophores and two other types of chromatophores occur in the part adjacent to the blood vessel wall. The organization of the epidermis and blood vessels of the skin is discussed with regard to terrestrial life in these amphibious fishes. © 1992 Wiley-Liss, Inc.
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  • 62
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    Journal of Morphology 214 (1992), S. 321-332 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pattern of complexity of cranial sutures is highly variable both among and within species. Intentional cranial vault deformation in human populations provides a controlled natural experiment by which we were able to quantify aspects of sutural complexity and examine the relationship between sutural patterns and mechanical loading. Measures of sutural complexity (interdigitation, number, and size of sutural bones) were quantified from digitized tracings of 13 sutures and compared among three groups of crania (n = 70) from pre-European contact Peru. These groups represent sample populations deformed in (1) anteroposterior (AP) and (2) circumferential (C) directions and (3) an undeformed population. Intergroup comparisons show few differences in degree or asymmetry of sutural interdigitation. In the few comparisons which show differences, the C group is always more interdigitated than the other two while the AP group has more sutural bones. The sutures surrounding the temporal bone (sphenotemporal, occipitotemporal, and temporoparietal) most frequently show significant differences among groups. These differences are related to the more extreme binding of C type deformation and are consistent with hypothesized increases in tension at coronally oriented sutures in this group. The larger number of sutural bones in the AP group is consistent with the general broadening of the cranium in this group and with experimental evidence indicating the development of ossicles in areas of tension. We suggest that so few changes in sutural complexity occurred either because the magnitude of the growth vectors, unlike their direction, is not substantially altered or because mechanisms other than sutural growth modification are responsible for producing the altered vault shapes. In addition, the presence of fontanelles in the infant skulls during binding and the static nature of the binding may have contributed to the similarity in complexity among groups. © 1992 Wiley-Liss, Inc.
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  • 63
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    Journal of Morphology 211 (1992), S. 87-93 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The administration of insulin to Triturus cristatus confirms its action in depletion of the adrenalin (A) granules of the adrenal chromaffin cells and the subsequent activation of phenylethanolamine-N-methyltransferase (PNMT). Treatment was carried out in March, when noradrenalin (NA) and A granules are present in almost equal quantities in the chromaffin cells, and in June, when NA granules largely prevail. After insulin administration, adrenalin content of the specimens treated in March decreases from 2.44 granules/μm2 to 0.28 granules/μm2; on the other hand, adrenalin content of the specimens treated in June increases from 0.19 granules/μm2 to 0.31 granules/μm2. These results suggest that in T. cristatus insulin acts both as an adrenalin-releasing agent and as a stimulator of PNMT activity.
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  • 64
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    Journal of Morphology 211 (1992), S. 147-163 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Variation in myology of the hind limb among salamanders has been poorly characterized. Nineteen major hind limb muscles of Ambystoma tigrinum (Ambystomatidae) and Dicamptodon tenebrosus (Dicamptodontidae) were studied to provide baseline descriptive data on hind limb myology in salamanders and to generate hypotheses of hind limb muscle function. Most superficial muscles of the hind limbs span multiple joints, including a unique three-joint muscle, the ischioflexorius, that extends from the pelvic girdle to the plantar fascia. The deeper hind limb muscles spen single joints. No myological diffrences were observed between the hind limbs of A. tigrinum larvae and individuals that had just metamorphosed. Fully adult tiger salamanders that had been housed in terraria for many years had hypertrophied femorofibularis and ischiofemoralis muscles, a condition similar to that reported in Paramesotriton and Taricha, which engage in terrestrial locomotion. In contrast, adults of D. tenebrosus, which are also good walkers, possess a hypertrophied ischioflexorius muscle and a reduced femorofibularis. These regular myological diffences, and those described by previous workers for different salamnder taxa, may be associated with differences in life-history traits, and in the case of A. tigrinum, with patterns of muscle use.
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  • 65
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    Journal of Morphology 211 (1992), S. 187-199 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Seven jaw muscles of the American alligator have been analyzed for histochemical characteristics of their fiber types: Musculus depressor mandibulae (MDM), M. pseudotemporalis (MP), M. adductor mandibulae posterior (MAMP), M. adductor mandibulae externus (MAME, profound and superficial portions), M. intramandibularis (MI), M. pterygoideus anterior (MPta), and M. pterygoideus posterior (MPtp). Classification of muscle fibers in previous studies has been based on (1) the staining properties of myosin ATPase after alkaline and acid preincubations and (2) the staining reactions for SDH, α-GPDH, PAS, and myosin ATPase after alkaline preincubations. In this study fiber types in one group of muscles (MP, MAMP, profound portion of MAME and MI) are classified (1) as type I, IIa, or IIb fibers, according to the system of Brooke and Kaiser (Arch. Neurol. 23:369-379, '70) or (2) as fast twitch glycolytic (FG), fast oxidative glycolytic (FOG), slow oxidative (SO), and tonic (few in number) fibers, according to the system of Putnam et al. (J. Exp. Zool. 214:303-309, '80). A second group of muscles (MDM, MAME superficial portion, MPta, and MPtp) reacted differently in similar histochemical tests and are classified, respectively, as (1) types 1, 2, 3 or (2) types A, B, C. We have distinguished the fiber types as red, intermediate, white, and tonic in analyses on muscle sections. The highest percentage of red and intermediate fibers is found in the MI. All three fiber types are approximately equal in superficial and medial portions of the MDM and the MPtp. Three muscles (MP, MAMP, and MAME) have the highest white fiber composition. These results indicate a correlation between the histochemical profiles of individual muscles and their functions during masticatory movements.
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  • 66
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    Journal of Morphology 211 (1992), S. 221-241 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transmission electron microscopy reveals that the ovaries of Ferosagitta hispida contain four somatic tissues. A myoepithelial ovary wall, continuous with a thin layer of peritoneocytes lining the coelomic cavity, encloses a fluid-filled ovarian space in which oocytes develop. Lamellar extensions of a “follicular reticulum” branch throughout the ovarian space and ensheath developing oocytes. This tissue has been overlooked in most previous studies of chaetognath ovaries. A bipartite oviductal complex extends the length of each ovary just within the lateral ovary wall. It consists of a flattened, blindly ending cellular tube, herein referred to as the cellular sheath, and an enclosed syncytium. Sheath cells secrete an electron-dense product into the ovarian space. Those sheath cells directly bordering the syncytium are contractile and are joined to the to the syncytium by gap junctions and microvillar interdigitations. The syncytium contains a complex of membrane-bounded lumina. The latter sometimes enclose sperm received during mating or ovulated eggs. Thus the syncytium serves both as a seminal receptacle and as a duct for passage of eggs to the outside. Contrary to several classical reports, the cellular sheath and syncytium of the oviductal complex do not separate at ovulation to form a temporary oviductal lumen.
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  • 67
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    Journal of Morphology 211 (1992), S. 275-284 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Investigated by light microscopy, the nerve pathways are described for the first time in the praesoma of a species of Rhadinorhynchidae. The pathways are described for 18 nerves, eight paired and two single, which originate from the cerebral ganglion and a post-ganglionic cell and terminate in the body wall musculature and the proboscis. The location of three commissures formed by these nerves is also described.
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  • 68
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    Journal of Morphology 212 (1992), S. 27-35 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The twitch fibers of the quail pectoralis muscle were found to have one neuromuscular junction each, located in the middle third of the fiber. The length of isolated fibers varied between 8.8 and 33.2 mm, with mean and median values of 16 and 15.6 mm, respectively. The lengths of the fascicles from which the fibers were isolated varied between 30 and 51 mm. The muscle fibers taper at both ends. The neuromuscular junctions, revealed after histochemically reacting the intact muscle for acetyl cholinesterase activity, were arranged in discrete bands, separated by intervals of between 0.94 and 6.70 mm, with a mean value of 3.14 mm. The quail pectoralis muscle is thus composed of discontinuous, tapered muscle fibers, arranged in an overlapping series. It is therefore a muscle in which tension is transmitted laterally between muscle fibers.
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  • 69
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    Journal of Morphology 212 (1992), S. 109-122 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Many skeletal muscles, including the feline biceps femoris, are composed of short, tapered myofibers arranged in an overlapping longitudinal series. The endomysium of such muscles transfers tension between overlapping myofibers, and is thus an elastic element in series with them. The endomysium of the cat biceps femoris contains curvilinear collagen fibrils in an approximately isotropic (random) array. The collagen fibrils undergo only a modest reorientation as the myofibers shorten or lengthen within the physiological range. A geometrical model predicts no change in the thickness of the endomysium on changing muscle fiber length and quantifies the expected collagen fibril reorientation in the endomysium as a function of muscle extension. It is also demonstrated that a high proportion of the collagen fibrils will be curvilinear at all sarcomere lengths. The organization of endomysial collagen is appropriate for the transfer of loads between myofibers by means of shear. © 1992 Wiley-Liss, Inc.
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  • 70
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    Journal of Morphology 212 (1992), S. 155-162 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A histological study of the pre-oral spine and associated structures in Argulus japonicus reveals that two exceptionally long and slender muscles casuse retraction of the spine into the spinal sheath. Originating from the body wall mid-dorsally the two muscles proceed through the nerve ring and the blood-filled lumen of the spinal sheath before being inserted on a bolster of tissue constituting the base of the spine. Movement of the spinal sheath is affected by two muscles originating from a common apodeme in the dorsal body wall, just posterior to the nauplius eye, and inserted on the lateral walls of the base of the spinal sheath.Two ducts, each leading from a glandular complex in the lateral parts of the carapace, proceed rostrally through the haemocoelic spaces. After passing the tritocerebrum laterally they accompany the retractor muscles of the spine on their course to the base of the spine. Passing through the bolster of tissue at the base of the spine the two ducts run all the way up to the tip of the spine where they open separately.The glandula praeboscoidalis is not associated with the pre-oral spine since its duct runs posteriorly in the wall of the proboscis. The labial spines are associated with giant glandular cells located beneath the optic tracts. © 1992 Wiley-Liss, Inc.
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  • 71
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    Journal of Morphology 212 (1992) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 72
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    Journal of Morphology 212 (1992), S. 257-267 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ontogeny of various middle-ear structures was examined in 11 groups of chicks between 10 days embryonic and adult. Measurements of the tympanic membrane surface area and height, columella length, and that of the columella footplate, annular ligament, and oval window area were obtained using video micrographs and computer digitization techniques. The oval window matures first at 53 days post-hatching, whereas the columella achieves adult size at 74 days. The tympanic membrane surface area is the last middle-ear variable studied to reach adult size (79 days post-hatch). The columella increases its length from 0.63 mm (10 days embryonic) to 2.73 mm in the adult. The tympanic membrane area expands by 280% whereas the columellar footplate area increases by 11x. As a result, the pressure amplification of the middle ear due to the tympanic membrane/columellar footplate area ratio improves by over 400%. These data further contribute to our understanding of the functional development of the middle ear. © 1992 Wiley-Liss, Inc.
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  • 73
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    Notes: A series of studies by Edgeworth demonstrated that cranial muscles of gnathostome fishes are embryologically of somitic origin, originating from the mandibular, hyoid, branchial, epibranchial, and hypobranchial muscle plates. Recent experimental studies using quail-chick chimeras support Edgeworth's view on the developmental origin of cranial muscles. One of his findings, the existence of the premyogenic condensation constrictor dorsalis in teleost fishes, has also been confirmed by molecular developmental studies. Therefore, developmental mechanisms for patterning of cranial muscles, as described and implicated by Edgeworth, may serve as structural entities or regulatory phenomena responsible for developmental and evolutionary changes. With Edgeworth's and other studies as background, muscles in the ventral gill arch region of batoid fishes are analyzed and compared with those of other gnathostome fishes. The spiracularis is regarded as homologous at least within batoid fishes, but its status within elasmobranchs remains unclear; developmental modifications of the spiracularis proper are evident in some batoid fishes and in several shark groups. The peculiar ventral extension of the spiracularis in electric rays and some stingrays may represent convergence, probably facilitating ventilation and/or feeding in both groups. The evolutionary origin of the “internus” and “externus” remains uncertain, despite the fact that a variety of forms of the constrictor superficiales ventrales in batoid fishes indicates an actual medio-ventral extension of the “externus.” The intermandibularis is probably present only in electric rays. The “X” muscle occurs only in electric rays and is considered to be Edgeworth's intermandibularis profundus. Its association with the adductor mandibular complex in narkinidid and narcinidid electric rays may relate to its functional role in lower jaw movement. Contrary to common belief, in most batoid fishes as well as some sharks, muscles that originate from the branchial muscle plate and extend medially in the ventral gill arches do exist: the medial extension of the interbranchiales in most batoid fishes and some sharks and the “Y” muscle in the pelagic stingrays Myliobatos and Rhinoptera. The latter is another example of the medial extension of the “internus.” Whether the interbranchiales and “Y” muscle are homologous within elasmobranchs and whether homologous with the obliques ventrales and/or transversi ventrales of osteichthyan fishes await further research. Four hypobranchial muscles are recognized in batoid fishes: the coracomandibularis, coracohyoideus, coracoarcualis, and coracohyomandibularis. The coracohyoideus is discrete from the coracoarcualis; its complete structural separation from the latter occurs in several groups of batoid fishes. The sternohyoideus of osteichthyan fishes is regarded as a partially developed, continuous bundle of muscle whose counterpart in chondrichthyan fishes appears to be the fully developed rectus cervicus in holocephalans and the squaloid shark Isistius. The coracoarculais is, therefore, present structurally and possibly functionally as a discrete muscle only in elasmobranchs. Although the coracohyomandibularis has been regarded as unique in batoid fishes, the first coracobranchialis in the sawshark Pristiophorus may represent the coracohyomandibularis. The conceptual frameworks and results of the development and evolution of cranial muscles presented here emphasize the importance of molecular and experimental embryological studies and integration of these areas with comparative anatomical and functional studies. Edgeworth's contributions remain as a remarkable achievement in muscle biology. © 1992 Wiley-Liss, Inc.
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  • 74
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    Journal of Morphology 213 (1992), S. 33-45 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Autogeneic bone marrow was implanted into an artificially created cavity in a segment of rat sciatic nerve, after removal of nerve fascicles, without damaging the epineurium or surrounding microcirculation. Under these conditions, the bone marrow induces capillary growth and forms granulation tissue from surrounding tissues, the behavior of pericytes being studied in the preformed (preexisting) postcapillary venules of the latter. Beginning 20 h after bone marrow implantation, the pericytes of the preexisting postcapillary venules hypertrophy, with shortening of their processes, prominent nucleoli, dispersal of ribosomes into their free form, fragmentation of basal lamina, and increased DNA synthesis. The number of contact surfaces between pericytes and endothelium is noticeably lower than in controls. Many pericytes are in mitosis. Cells with a shape transitional between pericytes and interstitial fibroblast-like cells appear. In some cases, Monastral Blue (MB) was used as a marker of the cells in preexisting venule walls of the graft bed. In the earlier stages of the experiment, the MB labelling is restricted to the cytoplasm of pericytes and endothelial cells of postcapillary venules, and to the macrophages that occur in the space between pericytes and endothelium. Furthermore, the marker continues to be observed, at a later stage, in some of the following cells: pericytes and endothelial cells of the newly formed vessels, macrophages migrating into the interstitium, transitional cells between pericytes and fibroblasts, and typical fibroblasts of the granulation tissue. The present study provides greater evidence that preformed microvasculature pericytes are substantially activated during postnatal angiogenesis and granulation tissue formation, suggesting that they may contribute to the origin of new pericytes and fibroblasts. © 1992 Wiley-Liss, Inc.
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  • 75
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    Journal of Morphology 213 (1992), S. 105-145 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphological corollaries of flightlessness of the kakapo (Strigops habroptilus) have been studied using skin specimens, skeletons, and pectoral dissection of an anatomical specimen. These have been compared with the closely related, flighted kea (Nestor notabilis), and secondarily with other Psittaciformes and the convergent hoatzin (Cuculiformes: Opisthocomus hoazin). S. habroptilus is the most massive and sexually dimorphic psittaciform in the world, and has the smallest relative wing size of any parrot. Alar pterylography of S. habroptilus is similar to that of other parrots, but remiges of the species are shorter, comparatively rounded, show less asymmetry of vanes, and have fewer interlocking barbules distally. S. habroptilus shows peculiarities of the sternum (vestigial carina, shortened spina externa), coracoid (elongate processus lateralis, enlarged angle with scapula), and humerus (prominent tuberculum ventrale, undercut crista bicipitalis). Pectoral skeletal dimensions of S. habroptilus are smaller than those of N. notabilis, whereas the reverse is true for pelvic dimensions. Most skeletal dimensions of S. habroptilus are more variable (within sexes) than those of N. notabilis. Proximal wing elements are disproportionately long and distal elements disproportionately short in S. habroptilus. The legs of S. habroptilus are characterized by disproportionately long femora and disproportionately short tarsometatarsi. Distinctive features of the pectoral musculature of S. habroptilus include a greatly reduced Mm. pectoralis thoracica and supracoracoideus, the absence of a distinct proximal muscle belly of M. propatagialis tendo longus, an extensive M. cucullaris capitis clavicularis associated with a voluminous crop, and an essentially tendinous M. sternocoracoideus. Relative to mean body mass, all dimensions of the antebrachial, carpometacarpal, digital, and patagial muscles are smaller in S. habroptilus than in N. notabilis. These aspects are compared to those of other flightless birds. Discussed are implications of flightlessness and associated large body size of S. habroptilus for issues of thermodynamics, metabolism, activity patterns, digestive anatomy, diet, reproduction, and insularit. © 1992 Wiley-Liss, Inc.
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  • 76
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    Journal of Morphology 214 (1992), S. 83-96 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the guinea pig, the estrous cycle is characterized by constant measurable level of plasma progesterone with two peaks: the first one associated with the peak of plasma estradiol-17β occurring at proestrus and the second, during diestrus, more pronounced at the time at which the level of estradiol-17β is undetectable. The progesterone receptor content is the highest on day 1 and the lowest on day 10 of the estrous cycle, which lasts 16.3 · 1.5 days (n = 37; mean · SD). There is a positive correlation between the plasma level of estradiol-17β and the progesterone receptors detected immunocytochemically in both endometrial epithelial and stromal cells. The general morphology of the endometrium during prcestrus and estrus is consistent with an estrogenic stimulation, i.e., a smooth and regular surface of the endometrium and the presence of numerous microvilli on the cell surface. However, a moderate secretory activity also occurs in proestrus and estrus. During postestrus, the glandular cells display an increase in characteristic secretory features which parallels the rise of progesterone in the plasma. © 1992 Wiley-Liss, Inc.
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  • 77
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    Journal of Morphology 214 (1992), S. 121-121 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 78
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    Notes: The postlarval development of gill raker denticles is described for the engrauloid (anchovy) genera Coilia, Lycothrissa, Setipinna, Thryssa, Stolephorus, and Encrasicholina based on scanning electron microscopy. The raker structure of adult Papuengraulis is also described. In the coiliid genera Coilia, Lycothrissa, Setipinna, Thryssa, and Papuengraulis, denticle development is not confined to particular region(s) of the raker. With few exceptions, the proliferation of denticles with growth is greatest along the upper raker edge; denticles are smaller and less dense on the raker faces and along the lower raker edge. Some Thryssa and Setipinna have a derived condition of denticle clustering along the upper raker edge. In Stolephorus and Encrasicholina, denticle development is confined to the upper raker half and includes the development of a single row of denticles along each raker face. A phylogenetic analysis of engrauloid raker structure, incorporating data from Bornbusch ( 88: Copeia 1988:174-182) and based on outgroup comparisons, indicates that for the Engrauloidea: (1) the pattern of denticle development shared by coiliids is plesiomorphic; and (2) the pattern of denticle development shared by Stolephorus, Encrasicholina, and most other engraulids is synapomorphic for the Engraulidae. There is no evidence that the studied coiliids Stolephorus and Encrasicholina are suspension feeders. The engraulid pattern of raker denticle development which is retained in suspension feeding engraulids of the genus Engraulis was thus derived before the derivation of suspension feeding in Engraulis. Comparative morphological and phylogenetic studies of clupeomorph raker structures and feeding behaviors can infer the historical origins of morphology-behavior associations, help define possible directions for analyses of raker denticle function, and thereby help elucidate the significance of structure-function couplings in the evolution of such clupeomorph trophic behaviors as suspension feeding. © 1992 Wiley-Liss, Inc.
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  • 79
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    Journal of Morphology 214 (1992), S. 131-138 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The echiuran worm Urechis caupo lives in U-shaped burrows in marine mudflats where levels of toxic hydrogen sulfide increase and water becomes hypoxic during low tide. Even in this low oxygen and high sulfide environment, the animal is capable of maintaining aerobic respiration. Gas exchange occures across both the body wall and hindgut. The hindgut functions as a type of water lung and is a thin walled, highly convoluted structure capable of considerable dilatation. It is rhythmically ventilated with water and its role as a respiratory organ becomes increasingly important as ambient pO2 drops. In the deflated hindgut light microscopy reveals a pseudostratified appearing innermost mucosal epithelium composed of columnar cells with nuclei at different levels. When the hindgut is fully inflated, ultrastructural studies show a simple columnar epithelium with the nuclei at the same level. Ultrastructurally, the free surface of the hindgut cells bears numerous microvilli and a few cilia. The lateral cell membranes are highly folded in the deflated hindgut, but these folds are not visible in the fully inflated hindgut. The cytoplasm contains osmiophilic bodies which show a partially lamellated pattern which may be sulfide oxidizing bodies involved in sulfide detoxification. In the fully inflated hindgut, the entire perimeter of the lumenal mucosa is covered by electron dense inclusions, whose exact fuction is unknown. The lack of structural information on the respiratory organ of this echiuran worm renders the interpretation of its morphological and histological features at the ultrastructural level difficult, although the present study has broadened our understanding of the structural adaptations of the hindgut as a respiratory organ. © 1992 Wiley-Liss, Inc.
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  • 80
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    Journal of Morphology 214 (1992), S. 159-171 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The study of semithin (1 μ in thickness) and thin sections of Epon-embedded material reveals that Malpighian tubules of Formica polyctena are composed of a single cellular type throughout their length. No differentiated regions were observed. Ultrastructural traits of the epithelial cells are those of highly metabolic cells engaged in water and ion transport: large euchromatic nucleus, several nucleoli, abundant mitochondria, a conspicuous brush border, and basolateral infoldings. Lysosomes, smooth endoplasmic reticulum, and intercellular junctions are also well developed. Mineral concretions occur within the cells and in the lumen. However, the degree of development of these cytological traits is variable among the different cells. The tubules drain into the gut through a specialized posterior region of the midgut or ampulla. In this region, the epithelial cells, although usually taller and showing conspicuous basal infoldings, display cytological structures similar to those of the Malpighian tubules. © 1992 Wiley-Liss, Inc.
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  • 81
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    Journal of Morphology 214 (1992), S. 251-260 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study describes, quantifies, and compares the growth and development of the volant forelimb morphology of Myotis lucifugus with that of the terretrial forelimb morphology of Rattus norvegicus. In M. lucifugus there is (1) accelerated growth in forearm length after parturition, (2) cessation in growth of the midshaft diameter of the ulna just after the onset of osteogenesis, (3) proximal fusion of the radius and ulna, which results in the radius occupying 97% of the articular surface of the elbow joint in adults, (4) fusion between the cartilaginous distal epiphyses of the radius and ulna which results in formation of a radioulnar bridge that becomes fully ossified in adults, and (5) incomplete ossification of the ulna with a section of the diaphysis becoming ligamentous. None of these events occurs during development in R. norvegicus. © 1992 Wiley-Liss, Inc.
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  • 82
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    Journal of Morphology 214 (1992), S. 269-285 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fibula reduction is a key feature of avian limb evolution. In a combined comparative and experimental approach the present study analyses the trends of fibula reduction in extant birds and their developmental basis. The study of 55 species of birds reveals four different types of tibiotarsus-to-fibula relationships. Extremely small fibulae are associated with two types of limb modification: (1) elongations of the limb primarily affect the tibiotarsus, increasing its length more than that of the fibula; (2) miniaturizations of the limb reduce both tibiotarsus and fibula length, but are reglarly associated with structural reductions of the distal parts of the fibula. True structrual reductions are distinguished from relative size reductions. The specific features of fibula reduction are analyzed through experimental mesenchyme excisions in chick limb buds. The methodical variation of experimental parameters resolves a long-standing controversy about the effects of mesenchyme reductions on the patterns of skeletal formation. Mesenchyme excisions are shown to have unequal effects on the two zeugopod bones, affecting the fibula to a greater degree than the tibiotarsus. Several of the features seen in birds with advanced fibula reductions are paralleled by the effects of mesenchyme reductions. The consequences of this differential susceptibility of the skeletal blastemata are discussed both in terms of pattern formation in limb development and in terms of its bearing on the patterns of evolutionary limb reduction. It is concluded that thresholds of cell number and blastema size in development constrain the patterns of phenotypic variation in avian limbs. © 1992 Wiley-Liss, Inc.
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  • 83
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    Journal of Morphology 214 (1992), S. 299-320 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present a stereotaxic atlas of the brain of the trumpet-tailed rat or degu (Octodon degus), an hystricomorph rodent native to Chile and one which has become increasingly popular as a research animal, among other things because of its use as a model for diabetic catarcts and its tendency to become hyperglycemic. The atlas contains 38 transverse and two sagittal sections of the brain covering pros-, mes-, and rhombencephalon, as well as diagrams of the brain's surface anatomy. It was constructed from brains of young adult male degus but can be used readily in studies of adult females, since there is no apparent sexual dimorphism in the brain size of this rodent. Ninety percent of 40 experimental lesions used to check the accuracy of the atlas were correctly placed.The fore- and midbrain of the degu are generally more compact than corresponding regions of the brain in the laboratory rat (suborder Myomorpha) and the guinea pig (another hystricomorph). The amygdaloid complex extends further forward in the telencephalon. Major mesencephalic nuclei and fiber tracts are more rostral in position. However, superior and inferior colliculi are much longer in degus than rats. The basic organization of the rhombencephalon is similar in degus and rats, although there are clearcut differences in the length or size of some hindbrain nuclei. © 1992 Wiley-Liss, Inc.
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  • 84
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    Journal of Morphology 214 (1992), S. 351-356 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Configurations of the rectus abdominis in tadpoles of 60 anuran species in 13 families were examined. This muscle is present by Gosner stage 25 and does not change until late in metamorphosis. The anterior terminus of the r. abdominis usually is a straight, transverse front or fan-shaped array only loosely associated with the rectus cervicis. In some suspension feeders (Rhinophrynus, Xenopus, but not microhylids), macrophagous suction feeders (Lepidobatrachus) and bromeliad inhabitants (Hyla bromeliacia) the r. abdominis is contigous with the r. cervicis which continues anterolaterally and dorsally from the wall of the spiracular cavity. Suctorial forms (Scutiger), those that live in confined spaces (burrowers, Centrolenella; bromeliad inhabitants, Hyla bromeliacia), and the taxa that have the r. cervicis and r. abdominis contiguous all have closed myosepta; the myosepta of other taxa; except for ones with large tadpoles (e.g., Rana catesbeiana), have large gaps between at least anterior myotomes. These initial data suggest that the configurations of the r. abdominis have responded to selection based on ecomorphological function and convergence among lineages are noted. © 1992 Wiley-Liss, Inc.
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  • 85
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    Journal of Morphology 211 (1992), S. 31-39 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cave-dwelling shrimp, Troglocaris schmidtii, has a unique mode of lipid storage. The lipid lies extracellularly in specialized compartments of the hepatopancreas, named oleospheres. The lipid is synthesized in the R-cells of the hepatopancreatic epithelium and accumulates in lipid droplets which fuse to form bigger globules. Mature lipid globules display moderately electron dense centers probably comprising triglycerides, and a broad electron dense boundary presumably consisting of lipoproteins. The globules are discharged into the lumen of the hepatopancreatic tubules by a kind of apocrine secretion. There, they coalesce to form larger masses. Finally, these lipid masses are transported into the oleospheres through a valve-like structure. The continual accumulation of lipid results in a drastic expansion of the oleospheres up to 500 μm in diameter. The absence of food in the digestive tract and the inactivity of the digestive enzyme producing F-cells indicate that digestion is suspended in the period of oleosphere formation. The curious mode of lipid storage in T. schmidtii may represent an adaptation to the extreme environmental conditions of a cave.
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  • 86
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 73-85 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have begun a comparative study of pigment patterns and their mechanisms of formation in ambystomatid salamanders in an attempt to elucidate the evolution of these traits in this family. In Ambystoma t. tigrinum, the migration of the prospective pigment cells was followed by using scanning electron microscopy and light microscopy combined with markers (dopa incubation for detecting melanophores, ammonia-induced pterin fluorescence for detecting xanthophores). The pigment pattern resulting from the cell migration shares features both with the alternating vertical xanthophore and melanophore bars of A. mexicanum and the horizontal stripes of certain salamandrids and ambystomatids. The pigment pattern of A. t. tigrinum is interpreted here as an intermediate evolutionary step between a primitive horizontal stripe pattern and a derived vertical bar pattern. The initiation of pigment pattern formation resembles the situation in A. mexicanum, probably reflecting the close phylogenetic relationship between the two taxa.
    Additional Material: 18 Ill.
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  • 87
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Direct development in amphibians is an evolutionarily derived life-history mode that involves the loss of the free-living, aquatic larval stage. We examined embryos of the direct-developing anuran Eleutherodactylus coqui (Leptodactylidae) to evaluate how the biphasic pattern of cranial ontogeny of metamorphosing species has been modified in the evolution of direct development in this lineage. We employed whole-mount immunohistochemistry using a monoclonal antibody against the extracellular matrix component Type II collagen, which allows visualization of the morphology of cartilages earlier and more effectively than traditional histological procedures; these latter procedures were also used where appropriate. This represents the first time that initial chondrogenic stages of cranial development of any vertebrate have been depicted in whole-mounts.Many cranial cartilages typical of larval anurans, e.g., suprarostrals, cornua trabeculae, never form in Eleutherodactylus coqui. Consequently, many regions of the skull assume an adult, or postmetamorphic, morphology from the inception of their development. Other components, e.g., the lower jaw, jaw suspensorium, and the hyobranchial skeleton, initially assume a mid-metamorphic configuration, which is subsequently remodeled before hatching. Thirteen of the adult complement of 17 bones form in the embryo, beginning with two bones of the jaw and jaw suspensorium, the angulosplenial and squamosal. Precocious ossification of these and other jaw elements is an evolutionarily derived feature not found in metamorphosing anurans, but shared with some direct-developing caecilians. Thus, in Eleutherodactylus cranial development involves both recapitulation and repatterning of the ancestral metamorphic ontogeny. These modifications, however, are not associated with any fundamental change in adult morphology and cannot at this time be causally linked to the evolutionary success of this extraordinarily speciose genus.
    Additional Material: 11 Ill.
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  • 88
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 179-186 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transmission electron microscopy of the spermatozoa of eight species (from seven genera) of holothurians has shown that each species has a sperm with unique dimensions, indicating that spermatozoon morphology can be used as a taxonomic character. However, although the structure of the sperm is species-specific, all sperm have a similar appearance which is typical of holothurians. The sperm head is composed of a spheroidal nucleus (about 2 μm diameter) which has a large anterior fossa housing the approximately spherical acrosome. The acrosome is differentiated internally and surrounded by periacrosomal material. The mid-piece consists of a single mitochondrion with lamellar cristae which surrounds the eccentrically positioned centrioles. The conservative form and arrangement of the sperm organelles suggest that sperm morphology cannot be used for phylogenetic investigations within this taxon.
    Additional Material: 3 Ill.
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  • 89
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 213-220 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An otolith increment is composed of an incremental zone and a discontinous zone. Observation of the otoliths of Oreochromis niloticus with transmission and scanning electron microscopy reveals that organic fibers are concentrated in the discontinuous zone and are relatively scarce in the incremental zone. On the other hand, calcium carbonate crystals are chiefly packed in the incremental zone and are less dense in the discontinuous zone. Both fibers and crystals are oriented perpendicular to the growth increments. Otolith checks, or discontinuities, contain even denser fibers and fewer fine crystals than does the discontinuous zone. A higher proportion of individual fibers is prominently stained in the discontinuous zone and check than in the incremental zone. Other features of individual fibers appear to be the same among the three zones. The crystals on either side of a check or a discontinuous zone resemble each other both in size and orientation. Zonation of protein and mineral components of otoliths can be understood in terms of both incremental growth and the daily cycle of deposition.
    Additional Material: 3 Ill.
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  • 90
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 269-273 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The glomerulocyte is a type of blood cell in the compound ascidian, Polyandrocarpa misakiensis. It is a discoidal cell, measuring 12-13 μm in diameter and about 3 μm in thickness. The outer half of the cell is occupied by concentrically-arranged fibers, usually 0.2-0.3 μm thick; the nucleus and organelles are confined to the central cytoplasm. The ordinary epidermal cells are columnar and are characterized by an apical homogeneous cytoplasmic bulge, vesicular bodies in the cytoplasm, and juctions between them. Growing or immature glomerulocytes are found only in the epidermis. They have intracellular fibers and vesicular bodies, and there are juctions between them and epidermal cells. These facts strongly suggest the origin of the glomerulocyte from an epidermal cell. However, no definite statement can be made as yet because earliest stages of differentiation have not been observed. The glomerulocyte fully differentiated in the epidermis is apparently released into the hemocoel.
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  • 91
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 307-317 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Descriptions are provided of the histology and ultrastructure of the male internal reproductive tracts from three species of Camponotus, representing three subgenera. This study is the first to provide ultrastructural information on the testes (including spermatogenesis and spermiogenesis), seminal vesicles, and accessory glands in ants. Testes contain about ten follicles each, and each follicle is capable of producing hundreds of cysts in which spermatozoa develop. Structural evidence of meiosis in late pupal testes includes cytoplasmic bridges between spermatocytes, centriole elimination, and fusion of mitochondria. Developing spermatids are in close contact with cyst cells in the region of the acrosome. Mature spermatozoa are similar in ultrastructure to those described previously for two other subfamilies of ants (Myrmicinae and Dolichoderinae). The ultrastructure of the seminal vesicle suggests that it is not merely a passive organ for sperm storage. Large numbers of both mitochondria and membranous whorls suggest a pH-regulating and/or hormonal function. The accessory gland is made up of secretory cells that contain a diversity of secretory granules. SDS-PAGE reveals several proteins found in the accessory glands but absent in the adjacent genitalia. Preliminary analyses indicate that carbohydrate is an important component of accessory gland secretions.
    Additional Material: 23 Ill.
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  • 92
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 319-329 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure and the concentration of trace elements in the cementum layer in functional teeth of subadult alligators (ca. 120 cm to 160 cm total length) was studied by using scanning electron microscopy (SEM), microradiography, and electron microprobe analysis (EMPA). The cementum layer was hypertrophic and consisted of two layers: the fibrous layer and the calcified layer. The two layers undergo developmental changes as a result of resorption and replacement. During the tooth replacement in the American alligator, trace elements decreased at the base of the dentine layer; the resorption of the alveolar bone occurred simultaneously at the tooth socket. We concluded that the resorption of the cementum in the alligator provided a useful indication of the mechanism of tooth replacement in crocodilian.
    Additional Material: 9 Ill.
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  • 93
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 13-26 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dorsal surface of the tongue of the little tern, Sterna albifrons, has a distinctive anterior region for five-sixths of its length and a terminal posterior region. The anterior region observed by scanning electron microscopy is distinguished along its forward half by a median line from which median papillae protrude. The hind half of the anterior region has a median sulcus without papillae. The deciduous epithelium on both sides of the median line and sulcus bears scattered epithelial protrusions. The posterior lingual region has neither median papillae nor deciduous epithelium. So-called giant conical papillae are located in a transverse row between anterior and posterior regions. Delicate microridges adorn the surfaces of all outer epithelial cells in both regions.Examination of the dorsal lingual epithelium by light and electron microscopy provides histologic and cytologic criteria for distinguishing anterior and posterior regions. Basal cells are nearly alike throughout the dorsal epithelium. Intermediate layer cells of the anterior region contain numerous tonofibrils in electron-dense bundles composed of 10 nm tonofilaments. The outer layer is composed of electron-dense, well-keratinized cells, and electron-lucent epithelial protrusions are present on the expose surface of the outermost cells. Median papillae are composed of typical keratinized cells, which are nearly filled with keratin filaments. Intermediate layer cells in the posterior region of the tongue are nearly filled with unbundled tonofilaments. There is only a very thin outer keratinized layer in this region.
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  • 94
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    Journal of Morphology 212 (1992), S. 87-97 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Figures of Eberth are prominent extensive filamentous structures in the basal epidermal cells of larval amphibians. They are compared and contrasted qualitatively and quantitatively in a number of species of the three groups of living amphibians.Fully developed Figures consist of massive skeins of tonofilaments oriented in three dimensions and hinged on hemidesmosomes within the cell. The overall appearance of the Figures is similar in anurans, urodeles and Ichthyophis among the apodans. However, in terms of size and number per unit length of the proximal cell margin, the hemidesmosomes and the thickness or their emergent skeins in anurans and Ichthyophis differ significantly from those parameters in urodeles, a feature that is presumably independent of cell size. Figures are poorly developed or missing in embryos of Typhlonectes, which has no larval stage in its life history.These ubiquitous skeletogenous structures in the aquatic larval amphibians, among other things, could be protective of underlying delicate tissues and act as a stabilizer in bodily movement during swimming. They could also serve as a reserve of cytokeratin for use during later cellular division and sloughing.
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  • 95
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    Journal of Morphology 212 (1992), S. 123-140 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Echiniscus viridissimus possesses two organs that lie above the ventromedial body wall approximately at the level of the second and third pair of legs. Each organ is composed of one medial and two lateral cells and possesses a pair of convoluted ducts. The lateral cells produce and release profuse amounts of filamentous basement membrane-like material into the body cavity. The proliferated material persists en masse adjacent to the lateral cells and is associated with disrupted droplets of pigmented body cavity material (BCM). The medial cell is larger than the lateral cells and possesses numerous tubular invaginations in which droplets of BCM are frequently found. Each duct originates as an infold that becomes a simple channel in the lateral cell and continues through the medial cell in a deep groove covered by a long process of the lateral cell. Although the ducts lie on the medial cell surface, they are “internalized” at the base of deep clefts and isolated from the body cavity by “tight” zonulae adherentes junctions. In the medial cell the ducts have a cuticle-like lining and the associated plasma membrane is characterized by numerous saccular infolds containing flocculent material. The duct linings, which extend beyond the limits of the medial cell, project into the endocuticle and terminate on the lateral body wall. Because the lateral cells are producing and releasing profuse basement membrane and because material with an electron density similar to BCM is present in the saccules, the distal regions of the ducts and in the endocuticle, we propose (1) that the lateral cells are producing basement membrane to disassociate BCM and (2) that the medial cell is absorbing and via its ducts translocating that BCM to the endocuticle. Furthermore, because the medial cell exhibits characteristics of transporting epithelia, namely numerous tubular infolds of the outer surface, a layer of distended saccules surrounding the duct and a high density of mitochondria, we suggest that the medial cell also functions in ion or osmotic regulation. © 1992 Wiley-Liss, Inc.
    Additional Material: 24 Ill.
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  • 96
    ISSN: 0886-1544
    Keywords: cardiac muscle ; actin dynamics ; α-actinin ; vinculin ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When fluorescently labeled contractile proteins are injected into embryonic muscle cells, they become incorporated into the cells' myofibrils. In order to determine if this exchange of proteins is unique to the embryonic stage of development, we isolated adult cardiac myocytes and microinjected them with fluorescently labeled actin, myosin light chains, α-actinin, and vinculin. Each of these proteins was incorporated into the adult cardiomyocytes and was colocalized with the cells'native proteins, despite the fact that the labeled proteins were prepared from noncardiac tissues. Within 10 min of injection, α-actinin was incorporated into Z-bands surrounding the site of injection. Similarly, 30 sec after injection, actin was incorporated into the entire I-bands at the site of injection. Following a 3-h incubation, increased actin fluorescence was noted at the intercalated disc. Vinculin exchange was seen in the intercalated discs, as well as in the Z-bands throug hout the cells. Myosin light chains required 4-6 h after injection to become incorporated into the A-bands of the adult muscle. Nonspecific proteins, such as fluorescent BSA, showed no association with the myofibrils or the former intercalated discs. When adult cells were maintained in culture for 10 days, they retain the ability to incorporate these contractile proteins into their myofibrils. T-tubules and the sarcoplasmic reticulum could be detected in periodic arrays in the freshly isolated cells using the membrane dye WW781 and DiOC3[3], respectively. In conclusion, the myofibrils in adult, as in embryonic, muscle cells are dynamic structures, permitting isoform transitions without dismantling of the myofibrils.
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  • 97
    ISSN: 0886-1544
    Keywords: erythroid spectrin ; non-erythroid spectrin ; Z-line ; membrane ; neuromuscular junction ; developmental changes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe multiple human cardiac and skeletal muscle spectrin isoforms. Cardiac muscle expresses five erythroid α,β spectrin-reactive isoforms with estimated MR's of 280, 274, 270, 255, and 246 kD, respectively At least one nonerythroid α-spectrin of MR 284 kD is expressed in heart. While skeletal muscle shares the 280, 270, and 246 kD erythroid spectrins, it expresses an immunologically distinct 284 kD nonerythroid α-spectrin isoform. The 255 kD erythroid β-spectrin isoform is specific for cardiac tissue. By immunocytochemistry, both erythroid β- and nonerythroid α-spectrins are localized to costameres, the plasma membrane, and the neuromuscular junctional region.
    Additional Material: 7 Ill.
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  • 98
    ISSN: 0886-1544
    Keywords: cold-stable microtubules ; cold adaptation ; cytoskeleton ; antimitotic drugs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The tubulins of Antarctic fishes possess adaptations that favor microtubule for mation at low body temperatures (Detrich et al.: Biochemistry 28:10085-10093, 1989). To determine whether some of these adaptations may be present in a domain of tubulin that participates directly or indirectly in lateral contact between microtubule protofilaments, we have examined the energetics of the binding of colchicine, a drug thought to bind to such a site, to pure brain tubulins from an Antarctic fish (Notothenia gibberifrons) and from a mammal (the cow, Bos taurus), At temperatures between 0 and 200C, the affinity constants for colchicine binding to the fish tubulin were slightly smaller (1.5-2.6-fold) than those for bovine tubulin. van't Hoff analysis showed that the standard enthalpy changes for colchicine binding to the two tubulins were comparable (δH° = + 10.6 and + 7.4 kcal mol-1 for piscine and bovine tubulins, respectively), as were the standard entropy changes (δS° = +61.3 eu for N. gibberifrons tubulin, +51.2 eu for bovine tubulin). At saturating concentrations of the ligand, the maximal binding stoichiometry for each tubulin was ∼ 1 mol colchicine/mol tubulin dimer. The data indicate that the colchicine-binding sites of the two tubulins are similar, but probably not identical, in structure. The apparent absence of major structural modifications at the colchicine site suggests that this region of tubulin is not involved in functional adaptation for low-temperature polymerization. Rather, the colchicine site of tubulin may have been conserved evolutionarily to serve in vivo as a receptor for endogenous molecules (i.e., “colchicine-like” molecules or MAPs) that regulate microtubule assembly.
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  • 99
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992) 
    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
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  • 100
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    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 305-312 
    ISSN: 0886-1544
    Keywords: tubulin ; acetylated detyrosinated tubulin ; estramustine phosphate ; heparin ; poly-L-aspartic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Assembly properties of cod, bovine, and rat brain microtubules were compared. Estramustine phosphate, heparin, poly-L-aspartic acid, as well as NaCl, inhibited the assembly and disassembled both bovine and rat microtubules by inhibition of the binding between tubulin and MAPs. The assembly of cod brain microtubules was in contrast only marginally affected by these agents, in spite of a release of the MAPs. The results suggest that cod tubulin has a high intrinsic ability to assemble. This was confirmed by studies on phosphocellulose-purified cod tubulin, since the critical concentration for assembly was independent of the presence or absence of MAPs. The results show therefore that cod brain tubulin has, in contrast to bovine and rat brain tubulins, a high propensity to assemble under conditions which normally require the presence of MAPs.Even if cod MAPs, which have an unusual protein composition, were not needed for the assembly of cod microtubules, they were able to induce assembly of bovine brain tubulin. Both cod and bovine MAPs bound to cod microtubules, and bovine MAPI and MAP2 bound to, and substituted at least the 400 kDa cod protein. This suggests that the tubulin-binding sites and the assembly-stimulatory ability of MAPs are common properties of MAPs from different species, independent of the tubulin assembly propensity.
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