bluuebunny/crossref_metadata_2025_split huggingface dataset:
Follicle duct cell ultrastructure and eggshell formation in Triops cancriformis (crustacea, notostraca)
Authors: Trentini Massimo , Scanabissi Franca Sabelli 
Published: February 2005

AbstractElectron microscopy of the cells of the follicle duct of Triops cancriformis shows that the follicular ducts are lined by a single‐layered epithelium which also produces the eggshell material. The cytoplasm is rich in rough endoplasmic reticulum that synthesizes the eggshell material which subsequently aggregates into preformed vacuoles. Newly formed spheres of eggshell material are then excreted into the lumen. At the end of vitellogenesis the oocytes descend toward the longitudinal oviduct and pass through the eggshell material which fills the follicle ducts. The production of the eggshell and its chemical composition in some Phyllopoda are compared. The paper discusses the relationship between the eggshell construction and the reproductive biology of the population.
Electron microscopy of the leucocytes of the typhlosole in ammocoetes, with special attention to the antibody‐ producing cells
Authors: Fujii Tamotsu 
Published: February 2005

AbstractIn an attempt to determine the role in the immune responses of the typhlosole, a hematopoietic tissue along the ventral wall of the larval lamprey Lampetra reissneri, scanning and transmission electron microscopic observations were made on ammocoetes hyperimmunized with sheep red blood cells. Besides including the cells of the erythrocyte series, this tissue also contained the following leucocytes forming an amorphous parenchyma: the cells of the granulocyte series, the most predominant cell type, possessing a markedly lobed nucleus and membrane‐bounded granules of various sizes; the macrophages possessing primary and secondary lysosomes and long lamellipodia on the cell surface; the lymphocytes of a large nucleocytoplasmic ratio with a number of long, spiky microvilli, constituting a major type of rosette‐forming (antigen‐binding) cells; and the plasma cells possessing highly extended cisternae of rough endoplasmic reticula that are characteristic of the higher vertebrates. The immunoperoxidase technique, which employs rabbit antibodies against lamprey immunoglobulin, proved that these plasma cells do contain immunoglobulin. These results strongly indicate that the typhlosole of the larval lamprey, besides functioning as a hematopoietic tissue, is actively involved in the antibody responses. It is also stressed that the plasma cell occurs in the most primitive vertebrates as an immunologically competent cell.
Types of neurons and synaptic connections at hypostome‐tentacle junctions in Hydra
Authors: Kinnamon John C. , Westfall Jane A. 
Published: February 2005

AbstractUsing transmission electron microscopy of thin sections we have examined neuronal concentrations at hypostome‐tentacle junctions in Hydra littoralis. A total of 194 ganglion cells were counted in 587 serial thin sections of a single hypostome‐tentacle junction. We found two distinct types of ganglion cells: those with and those lacking stereocilia. The majority of the neurons observed lacked stereocilia; in a single hypostome‐tentacle junction only 37% of the ganglion cells possessed a kinocilium surrounded by rodlike stereocilia. Most of the ganglion cells (55%) were clustered together in the oral or upper epidermis of the hypostome‐tentacle junction: Nineteen percent were in the lateral and 26% in the aboral or lower epidermis. The two types of ganglion cells did not differ significantly in their distribution. Both types of ganglion cell had synaptic contacts with other neurons and with epitheliomuscular cells. More than 85% of the neuroneuronal and 61% of the neuroepitheliomuscular cell synapses were located in the oral epidermis of a hypostome‐tentacle junction. In addition, two‐way chemical synapses and a gap junction between neurons were observed at hypostome‐tentacle junctions. Our morphological evidence of synaptic connectivity in neuronal clusters at hypostome‐tentacle junctions suggests that primitive ganglia are present in Hydra.
Limb regenerative capacity of four species of Japanese frogs of the families hylidae and ranidae
Authors: Kurabuchi Shingo , Inoue Sakae 
Published: February 2005

AbstractThe regenerative capacity of limbs was investigated by amputation of limbs at the zeugopodium in postmetamorphic froglets and adults of various sizes in four species of Japanese frogs, all of which showed some regeneration at these ages. In Hyla arborea japonica and Rana brevipoda porosa most young froglets regenerated their limbs well; however, the rate of regeneration decreased with the age of amputation, and the limb became nonregenerative in adults. Limbs of adults in Rana rugosa and R. japonica, on the other hand, exhibited good regeneration. All of the regenerates in the four species were heteromorphic, consisting histologically of well‐developed cartilaginous rods surronded by connective tissue and skin. Limited development of muscle was appartment in regenerates of the three ranid species. The relations between body size, innervation of limbs, and regenerative capacity are discussed.
Synganglial and neurosecretory morphology of female Ornithodoros parkeri (cooley) (acari: Argasidae)
Authors: Pound J. Mathews , Oliver James H. 
Published: February 2005

AbstractSingle esophageal and paired cheliceral, palpal, pedal (I–IV), and opisthosomal nerves enter the synganglion and form specific neuropilar ganglia. The ganglia are integrated by a complex series of commissures and connectives. Eighteen paraldehyde‐fuchsin‐positive neurosecretory regions, which vary greatly in size and amount of granular neurosecretory material, are each associated (one or more) with neuropilar ganglia. Presumably transport of neurosecretory materials to target tissues occurs through axonal pathways, perineurial‐neural lamella associations, and the neurohemal retrocerebral organ complex.
Development of the skull of Dermophis mexicanus (amphibia: Gymnophiona), with comments on skull kinesis and amphibian relationships
Authors: Wake Marvalee H. , Hanken James 
Published: February 2005

AbstractThe development of the skull of Dermophis mexicanus (Caeciliidae) is described and compared to that of other caecilians. The chondrocranium is well developed in embryos of 25 mm total length (TL); ossification begins in the quadrate and the articular element of the lower jaw at about 30 mm TL. The occipital arch then ossifies, followed by the dorsal and lateral dermal bones, then the ventral endochondral and dermal elements. The stapes ossifies at 55 mm TL. The amount of skull roofing increases during ontogeny, although the anterior rims of the nasal capsules, the anterior part of the mesethmoid, and the hyoid apparatus remain cartilaginous throughout life. Dermophis mexicanus lacks many primary embryonic ossification centers reported by Marcus et al. ('35) for Hypogeophis; presence of these ossification centers has been presumed to be indicative of a primitive skull morphology derived with little modification from archaic amphibians (“stegocephalians”). The fetal skull is highly kinetic, and some kinesis is retained in adults. We suggest that fetal skull kinesis and early ossification of jaw suspension elements are functionally related to the intraoviducal feeding mode of this viviparous species. Based on this evidence, together with the observed ossification pattern and bone homologies, we conclude that stegokrotaphy (complete skull roofing) in caecilians is a derived condition, correlated with fossoriality, and does not indicate a direct relationship of caecilians to any known early amphibian taxon.
Active length‐tension relation and the effect of muscle pinnation on fiber lengthening
Authors: Muhl Zane F. 
Published: February 2005

AbstractThe active length‐tension relation was determined for the left digastric muscle of seven New Zealand White rabbits anesthetized with pentobarbital. Measurements of muscle length and fiber architecture were made from photographs of resting and actively contracting muscle. There was a marked difference between length‐tension curves based upon resting as compared to active muscle length. The active length‐tension relation had a longer descending limb than ascending limb, whereas the length‐tension relation based on passive muscle length tended to be symmetrical around optimum length. On the average, muscle fibers lengthened 0.77 mm for each 1 mm of extension of the muscle belly. Since the rabbit digastric muscle is unipinnate, this suggests that pinnation serves to enhance the range of muscle excursion in this muscle.
The structure of the head kidney in the mudskipper, Periophthalmus koelreuteri (pallas)
Authors: Safer A. M. A. , Tytler P. , El‐Sayed N. 
Published: February 2005

AbstractThe head kidneys of adult Periophthalamus koelreuteri contain many functional glomerular nephorns which on the basis of this histochemical study, are indistinguishable from those of the typical opistonephros of marine teleosts. The anterior lobes resemble, in location and in the presence of intertubular erythropoeitic tissue, the pronephros in other species. The single nephron found there, however, does not differ significantly from the other nephrons of the head kidney. It is suggested, therefore, that the nephrons of the head kidney in this species are opisthonephric in origin.
Sperm transport and storage and its relation to the annual sexual cycle of the female red‐sided garter snake, Thamnophis sirtalis parietalis
Authors: Halpert Andrew P. , Garstka William R. , Crews David 
Published: February 2005

AbstractFemale red‐sided garter snakes (Thamnophis sirtalis parietalis) store sperm from both late‐summer and spring matings. Before winter dormancy, sperm are stored in specialized furrows in the vaginal portion of the oviduct, 3–6 cm anterior to the vent. After 6 weeks in dormancy, the epithelial cells lining this vaginal region hypertrophy and stain strongly with periodic acid‐Schiff (PAS). This PAS+ epithelial border sloughs and associates with sperm. These aggregations of PAS+ material, which will be referred to as carrier matrices, move anteriorly through the oviduct. After 20 weeks in dormancy, most sperm are found in specialized infundibular storage regions. Spring mating induces a rapid degeneration of winter‐stored sperm. Stored sperm are evacuated from infundibular storage receptacles within 6 hours after mating. Yet sperm from the spring mating are not evident in the oviduct until 24 hours after mating. Carrier matrices begin to form at this time. At 48 hours after mating, sperm, often associated with carrier matrices, appear in the infundibulum. At 40 days after mating, most sperm have moved into infundibular storage receptacles. Evidence suggests that carrier matrices not only facilitate the transport of sperm anteriorly from vaginal to infundibular regions, but also function as nutritional stores.
A comparative immunocytochemical investigation of the crustacean hyperglycemic hormone (CHH) in the eyestalks of some decapod crustacea
Authors: Gorgels‐Kallen J. L. , Van Herp F. , Leuven R. S. E. W. 
Published: February 2005

AbstractThe eyestalk of the astacideans Orconects limosus, Nephrops norvegicus, and Homarus gammarus, and the palinuran Palinurus vulgaris, was examined with an antiserum raised against purified crustacean hyperglycemic hormone (CHH) of the astacidean species Astacus leptodactylus. A distinct immunopositive reaction occurs in a group of neurosecretory cells in the medulla terminalis ganglionic X‐organ (MTGX), in the MTGX‐sinus gland tractus, and in a considerable part of the sinus gland. The immunoreactive sites in the eyestalk of the investigated species correspond to the site of production, storage, and release of the CHH. Preliminary investigations with this antiserum also indicate that a positive immunoreaction can be obtained in the eyestalk of other decapod crustaceans, for example, of the brachyuran Macropipus puber and the caridean Palaemon serratus.
Cytological characterization of the germinal line during testicular differentiation in the lizard Liolaemus gravenhorsti (gray)
Authors: Leyton Víctor , Miranda E. , Bustos‐Obregón E. 
Published: February 2005

AbstractThe gross morphology, histology, and ultrastructure of Liolaemus gravenhorsti gonads prior to and after differntiation are described. Special emphasis has been given to characterization and changes of the germ cell line throughout intrauterine development and 3 days postpartum.During the pregonadal stage, the primordial germ cell migrates toward gonadal rudiments by way of the mesenchyme. These cells can easily be identified by their great size, voluminous and lobulated nucleus, great quantities of yolk platelets, microtubules, and numerous lipid inclusions. In the undifferentiated gonad, the germ cells (type 1 gonocytes) have an ovoid or spherical shape and autodigestion of yolk platelets, great development of Golgi complex, and mitochondrial aggregation, though fewer liposomes, pseudopodes, and microtubules were noted. Concomitantly with the beginning of mitosis, a third type of germ cell appears, the type 2 gonocytes, which are smaller, with poorly defined membranous systems in various degrees of involution. The seminiferous cords are organized when somatic cells of the medullar portion of the gonad surround type 1 gonocytes. Germinal cells are centrally localized in the cords. Near birth many gonocytes migrate toward the basal lamina of cords and differentiate into spherical prespermatogonia, with few organoids. Sertoli cells eparate them from the basal lamina. In advanced pregnancy, Leyding cells become numerous with morphology typical of androgen‐producing cells.
A forebrain atlas and stereotaxic technique for the lizard, Anolis carolinensis
Authors: Greenberg Neil 
Published: February 2005

AbstractA forebrain atlas and stereotaxic neurosurgical techniques were developed for use in anatomical and behavioral experiments on the green anolis lizard (Anolis carolinensis). Green anoles are convenient and robust experimental subjects with a rich behavioral repertoire, the social components of which are partly under hormonal control.The technique and atlas were devised to conduct neuroethological investigations of the effect of lesions on species‐typical display behavior. The atlas consists of 12 transverse sections from an average size adult male. The figures (4–15) are based on Nissl material and supplemented with fiber‐stained material from adjacent sections. They appear at the end of the article. Limitations on the accuracy of stereotaxic coordinates are discussed and tables of correlative nomenclature for principal telencephalic and diencephalic nuclei are provided.
Ultrastructural studies of the epidermal leydig cell in larvae of Salamandra salamandra (caudata, salamandrida)
Authors: Rosenberg Mira , Lewinson Dina , Warburg M. R. 
Published: February 2005

AbstractEpidermal Leydig cells observed in the ventral epidermis of Salamandra salamandra larvae from birth until metamorphosis are characterized by large vesicles and a supporting Langerhans net. They decline in number after birth and disappear entirely after metamorphosis. The cells change in structure and become larger, thus indicating a process of degeneration. The Leydig cells are continuously removed by macrophagelike cells after birth.
Mechanics of the limbs of the walrus (Odobenus rosmarus) and the california sea lion (Zalophus californianus)
Authors: Gordon Kenneth R. 
Published: February 2005

AbstractMoment arms and cross‐sectional areas of muscles from the forelimbs and hind limbs of Odobenus and Zalophus were used to estimate relative torques associated with several locomotor movements. Odobenus uses predominantly the hind limbs for aquatic propulsion, while Zalophus only uses the forelimbs. Torques contributing to locomotor movements used during the power and recovery strokes were substantially greater for the hind limbs of Odobenus and for the forelimbs of Zalophus. Apparently, the lineages of these two genera shared an aquatic ancestor during the Miocene; therefore, they also shared a common method of aquatic propulsion. This common method of aquatic propulsion could have been either forelimb, hind limb, or both. Since the Miocene then, the method of aquatic propulsion and the mechanical characteristics of the limbs have diverged for at least one of these two lineages. A model is advanced to explain key mechanical differences between Odobenus and Zalophus that enable Odobenus to maneuver effectively in a head‐down posture on the ocean floor.
S.E.M. and polarization microscopy of nemertean stylets
Authors: Stricker Stephen A. 
Published: February 2005

AbstractThe ultrastructure of the stylets produced by nine species of nemerteans has been examined by scanning electron microscopy (S.E.M.) and polarized light microscopy. Stylets are solid, nail‐shaped structures that typically reach lengths of 50–200 μm. Each stylet is composed of a centrally located organic matrix surrounded by an inorganic cortex that contains calcium and phosphorus. When viewed at high magnifications, fine granules can be seen throughout the organic matrix, and the cortex appears to be composed of densely packed homo‐geneous material. Fractured specimens and whole matrices isolated from decalcified stylets reveal a close correspondence between the shape of the organic matrix and that of the surrounding cortex. This similarity in morphology suggests that the organic matrix serves as a template during calcification of the stylet. The fact that abundant material can be seen in the core of incinerated stylets, and in the central region of stylets that had been soaked for several hours in sodium hypochlorite, supports the hypothesis that the organic matrix is also highly calcified. Polarization microscopy of nemertean stylets indicates that they are composed of a crystalline, rather than amorphous, form of calcium phosphate. The probable organization of the calcium phosphate crystals is discussed.
Observations on tooth development and implantation in the upper pharyngeal jaws in Astatotilapia elegans (Teleostei, Cichlidae)
Authors: Huysseune A. 
Published: February 2005

AbstractProminent stages in the development of teeth, associated with the upper pharyngeal jaws in early postembryonic stages of the mouth brooding cichlid A statotilapia elegans were studied on semithin sections in relation to changes in the underlying endoskeletal parts and to the formation of the dentigerous bone. Because the pattern of tooth implantation on infrapharyngobranchial III‐IV is constant, at least in early postembryonic stages, it is possible to trace the life history of a given tooth by tracing its homologue throughout the ontogenetic series. A probable causal relationship exists between tooth development and erosion of the underlying cartilage. Fully developed, though unerupted teeth, differentiate annular bone of attachment, which, depending on its position, is formed either outside the cartilage or within the previously induced erosion cavities. Attachment bone of adjacent teeth fuses to build up the dentigerous bone, which, as a result, may be situated within the area previously occupied by cartilage. As soon as the tooth has built up its bone of attachment, it may erupt. The collagenous matrix between tooth and attachment bone persists and gives rise to the movable connection between both. Differentiation of teeth on infrapharyngobranchial III‐IV, together with enlargement of the dentigerous bone, proceeds from the lateral and the rostral border, where new germs constantly form. The appearance of new germs on infrapharyngobranchial II is more unpredictable.
Structure‐function relationships of the flexor carpi radialis muscle compared among four species of mammals
Authors: McConathy D. , Giddings C. J. , Gonyea W. J. 
Published: February 2005

AbstractInvestigations of the structure and function of the flexor carpi radialis muscle (FCR) in the cat have led to the hypothesis that the compartmentalized (nonuniform) distribution of fiber types within the muscle relate to the complex motor skills of the cat. To test this hypothesis a study was undertaken to compare the FCR in four mammalian species of similar body size but with different forelimb motor tasks. The species chosen were: dog, opossum, armadillo, and cat. Comparisons were made among species with regard to general muscle morphology, fiber types and sizes, fiber proportions, and fiber distriburtions. The FCR of all species was morphologically similar and contained three muscle fiber types (SO, FOG, and FG). The mean area of muscle fibers was largest in opossum, while the FCR fibers of dogs were smallest. The percentage of SO fibers in the dog FCR was greater than in the other species studied. The opossum FCR also contained a high percentage of SO fibers. The armadillo FCR consisted of a high percentage of FG fibers. In the cat FCR the percentages of all three fiber types were similar. For each species, individual fiber proportions were in agreement with the results for fiber percentages. Compartmentalized distribution of fiber types existed in each species with the dog having the most compartmentalized fiber type distribution and the cat the least compartmentalized distribution. Therefore it seems that the compartmentalized organization of the FCR is not related to any specialized motor task, but may be a generalized pattern associated with motor patterns shared among all species studied.
The musculature of the papuan frog Phrynomantis stictogaster (Anura, Microhylidae)
Authors: Burton Thomas C. 
Published: February 2005

AbstractThe musculature of Phrynomantis stictogaster, a burrowing Papuan microhylid frog, of the subfamily Asterophryinae, is described and compared with accounts of other frogs. P. stictogaster exhibits unusual characters: dense musculature investing an entirely adherent tongue; exceptionally massive jaw musculature; and hitherto underscribed attachments of some muscles in the manus and pes. The presence of an accessory tendon to the M. glutaeus magnus and the pattern of distal thigh tendons confirm previous diagnosis of the Microhylidae, but the presence of an accessory head to M. adductor magnus is a condition previously not noted in the family. Features of the hyoid, pectoral, and thigh muscles resemble those of members of the subfamilies Dyscophinae, Microhylinae, and Spenophryninae.