bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and ultrastructure of the epididymis of the viviparous lizard during the annual hormonal cycle: Changes of the epithelium related to secretory activity
Authors: Mesure M. , Chevalier M. , Depeiges A. , Faure J. , Dufaure J. P. 
Published: February 2005

AbstractThis study deals with the structure and ultrastructure of the epithelial cells of the lizard (Lacerta vivipara Jacquin) epididymis as related to secretory activity. The epithelium contains only two types of cells, secretory cells and basal cells. The secretory cells undergo an annual cycle which has been divided into 10 stages. In its most active secretory state, epithelium forms 65.3% of the organ volume. The secretory cell is a tall columnar cell (from 55 ± 3.4 μm to 74.3 ± 2.4 μm height) with a basal nucleus and a supranuclear cytoplasm almost entirely occupied by numerous large secretory granules (5 to 7 μm in diameter). At the ultrastructural level, secretory cells contain rough endoplasmic reticulum (RER), Golgi complex, and secretory granules at various stages of synthesis before being discharged into the lumen. Each granule is membrane‐limited and contains a spherical electron dense central core and a peripheral vacuole which varies in density. The secretory cell originates from small cubic cells (13.8 ± 0.7 μm) with few organelles (stage 1). The height of the cell increases gradually and free ribosomes appear first (stage 2), followed by scarce elements of RER (stage 3). The step preceding the secretion period (stage 4) is characterized by a conspicuous increase in volume of RER and Golgi complex. From stage 7 to stage 10, the cell undergoes a dramatic involution. After a transient hypertrophy of the RER, numerous autophagic vacuoles invade the cytoplasm. This degeneration can lead to a complete lysis of the cell and to its rebuilding after elimination of the greatest part of the cytoplasm. The volume of the epithelium falls to 15.6% of the total volume. With antibodies raised against the protein family which constitutes the main part of the secretion (L proteins of 19 kDa), it is shown by immunohistochemistry that these proteins are concentrated into secretory granules which are discharged into the lumen to finally bind to the heads of the spermatozoa.
Functional morphological interpretation of the distribution of muscle spindles in the jaw muscles of the mallard (Anas platyrhynchos)
Authors: Bout R. G. , Dubbeldam J. L. 
Published: February 2005

AbstractThe morphology and distribution of muscle spindles of jaw and tongue muscles in the mallard were examined in serial transverse sections of single muscles and in horizontal sections of a whole head. Our observations on spindle morphology are in agreement with previous descriptions of spindles in birds. Some spindles differ in their innervation and the pattern of intrafusal muscle fibers. The spindles of individual adductor and pterygoid muscles are distributed unevenly. Some adductor muscles lack spindles, whereas those of other muscles are confined to limited areas. Jaw opening muscles and extrinsic tongue muscles lack spindles. The stretch of extrafusal muscle fibers could be estimated from the difference in sarcomere length for birds with the beak open and closed. Not all muscle fiber groups are stretched evenly over the whole range of jaw opening. Only those fiber groups that are continuously stretched during jaw opening contain spindles.
Ultrastructural investigations of presumed photoreceptive organs in two Saccocirrus species (polychaeta, saccocirridae)
Authors: Purschke Günter 
Published: February 2005

AbstractIn addition to the pigmented ocelli, four different types of photoreceptor‐like organs without shading pigment have been found in Saccocirrus papillocercus and S. krusadensis. The sensory cells of these presumed ocelli are either ciliary or rhabdomeric with ciliary rudiments. With the exception of the multicellular type‐2 ocelli they are bicellular consisting of a sensory cell and a supportive cell. In each ocellus the supportive cell forms a thin cup‐shaped envelope around the sensory elements. In the type‐2 ocellus, 7 supportive cells form an ovoid cavity leaving openings through which dendritic processes of an equal number of sensory cells enter the cavity. The pigmented ocelli possess an ocellar cavity communicating with the exterior through a pore in the eyecup, ciliary rudiments in both sensory and supportive cell, and additional non‐photoreceptive sensory cells in the opening of the eyecup. The sensory organs show characteristic differences between the two species, such as presence or absence of a particular type of ocellus (type 2 is absent in S. krusadensis, type 3 in S. papillocercus), number of cilia in type‐4 ocelli, density of microvilli, number of non‐photoreceptive sensory cells in the pore of the pigmented ocellus, etc. These differences provide important characters which can be used for discrimination either of species or of subgeneric taxa in Saccocirrus. The phylogenetic significance of the different photoreceptive organs is discussed.
Abnormal craniofacial development in cyclopic salmonid fishes
Authors: Bolker Jessica A. , Thomson Keith S. 
Published: February 2005

AbstractDifferent 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.
Liver ultrastructure of juvenile Atlantic salmon (Salmo salar)
Authors: Robertson John C. , Bradley Terence M. 
Published: February 2005

AbstractLight 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.
The vascular structure of the kidney of the neotenous axolotl and its metamorphosed counterpart
Authors: Ditrich H. , Splechtna H. 
Published: February 2005

AbstractThe renal vascular and glomerular structures of the kidney of neotenous and experimentally metamorphosed axolotls (Ambystoma mexicanum: Amphibia, Urodela) are investigated using light, transmission electron, and scanning electron microscopy of critical‐point dried specimens and vascular corrosion casts. The blood vascular system of the kidney in the axolotl is generally similar to that in other urodeles. The glomeruli are comparatively large and distincly ovoid (mean size 267 × 201 μm). Glomerular endothelial nuclei frequently bulge into the vascular lumen. Whereas the lamina rara externa and the lamina densa are quite uniform in diameter, the lamina rara interna shows a very irregular thickness with frequent interposed cellular processes. In the thyroxine‐metamorphosed animals, the glomerular surface decreased by a factor of approximately 36%; this was mainly due to the reduction of the glomerular diameter in the direction from vascular to urinary pole. No significant degeneration or new formation of renal tubules was observed during or after metamorphosis. A notable relative decrease in renal volume (approx. 57%) in the metamorphosed forms can be attributed mainly to a reduction in interstitial volume.
The comparative myology of the thigh and crus in the salamanders Ambystoma tigrinum and Dicamptodon tenebrosus
Authors: Ashley‐Ross Miriam A. 
Published: February 2005

AbstractVariation 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.
Histochemical study of jaw muscle fibers in the American alligator (Alligator mississippiensis)
Authors: Sato I. , Shimada K. , Sato T. , Kitagawa T. 
Published: February 2005

AbstractSeven 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.
An ultrastructural study on the origin of glomerulocytes, a type of blood cell in a styelid ascidian, Polyandrocarpa misakiensis
Authors: Hirose Euichi , Mukai Hideo 
Published: February 2005

AbstractThe 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.
The effects of silicate depletion and subsequent replenishment on the cytoplasmic fine structure of the silica‐secreting testate amoeba Netzelia tuberculata in laboratory culture
Authors: Anderson O. Roger 
Published: February 2005

AbstractIn 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.
Histological, histochemical, and biochemical changes in the annual oviduct cycle of the agamid, Calotes versicolor
Authors: Shanthakumari T. Ruth , Sarkar H. B. D. , Shivanandappa T. 
Published: February 2005

AbstractHistology, 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.
An ultrastructural study of differentiatation of pyriform cells and their contribution to oocyte growth in representative squamata
Authors: Andreuccetti Piero 
Published: February 2005

AbstractAn 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.
Patterns of peripheral innervation of the tongue and hyobranchial apparatus in caecilians (Amphibia: Gymnophiona)
Authors: Wake Marvalee H. 
Published: February 2005

AbstractThe 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.
Histology of the reproductive tract of hybrids between gonochoristic males and parthenogenetic females of Lepidodactylus lugubris in French Polynesia (Reptilia, Gekkonidae)
Authors: Girons Hubert Saint , Ineich Ivan 
Published: February 2005

AbstractParthenogenetic 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.
Development and differentiation of the eye in Platynereis dumerilii (Annelida, Polychaeta)
Authors: Rhode Birgit 
Published: February 2005

AbstractThe 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.