bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histological and Immunohistochemical Studies of the Neurohypophysis of Primitive Teleosts, the Osteoglossidae
Authors: Tsuneki K. , Nozaki M. 
Published: April 2010

AbstractThe neurohypophysis of three species of the Osteoglossidae (Osteoglossum bicirrhosum, Scleropages jardini and Heterotis niloticus) was studied histologically. The rostral part of the neurohypophysis abuts on the pars distalis of the adenohypophysis, but does not interdigitate with it. The caudal part of the neurohypophysis is stained densely with aldehyde fuchsin and extensively interdigitates with the pars intermedia, forming a neurointermediate lobe. This organization of the neurohypophysis is intermediate between that of holosteans and that of non‐osteoglossomorph teleosts. The median eminence‐like features of the rostral part of the neurohypophysis are distinct in the Osteoglossidae in contrast to non‐osteoglossomorph teleosts. In Osteoglossum bicirrhosum, immunohistochemical study reveals the presence of somatotropin release‐inhibiting factor‐like substance in the rostral part of the neurohypophysis. Fibers immunoreactive to anti‐arginine vasopressin occur in the neurointermediate lobe almost exclusively. These observations also may support the assumption that the rostral part of the neurohypophysis corresponds functionally to the median eminence. For comparison, the occurrence and distribution of somatotropin release‐inhibiting factor‐like substance, luteinizing hormone‐releasing factor‐like substance and arginine vasopressin‐like substance in the neurohypophysis of Gymnarchus niloticus are described.
Fibrogranular Material, Annulate Lamellae and Microtubules During Spermiogenesis in Drosophila melanogaster
Authors: Kessel Richard G. 
Published: April 2010

AbstractDuring spermiogenesis in Drosophila melanogaster, a “perinuclear plasm’ accumulates between the fenestrated portion of the nuclear envelope and an adjacent lamella of ER in the young spermatid. Microtubules appear within the perinuclear plasm and become especially concentrated in a nuclear concavity. Cytoplasmic pores are present locally within the lamella of ER. In addition, localized or discrete bodies composed of fibrogranular material become closely associated with single pore complexes in the lamella of ER. A close association exists between pore complexes (annulate lamellae), the small granular and fibrillar subunits of the fibrogranular bodies, polyribosomes and the nuclear‐associated microtubules during much of spermiogenesis. While the fibrogranular material becomes less concentrated during spermiogenesis, the number of pore complexes in a single section increases such that two, three or even four short annulate lamellae are intercalated within many longitudinally oriented microtubules which are present in the furrow of the spermatid nucleus. Structural relationships observed between cytoplasmic pores (annulate lamellae), fibrogranular bodies, polyribosomes and microtubules are discussed in relation to information about the timing of RNA and protein synthesis. This study extends previous observations about the distribution and structural variations of annulate lamellae elsewhere in the spermatid cytoplasm.
Posthatching Development of Vascularization, Arteriovenous Anastomoses and Seromucous Glands in the Avian Nasal Mucosa
Authors: Midtgård Uffe 
Published: April 2010

AbstractThe development of blood vessels and growth of different tissue compartments in the avian nasal mucosa were studied in chickens from hatching to 5 months of age. The vascularity of the rostral and middle nasal conchae increased about 4‐fold, while there was a progressive decrease in the relative size of the epithelium and connective tissue compartments, during the maturation period. Arteriovenous anastomoses (AVAs) were present already at hatching and their density increased 3‐fold during the second week of posthatching development. The seromucous glands form by a process of invagination of the epithelium, which occurs predominantly during the first week after hatching. The glands continue to grow in size and an increasing fraction of the cells becomes mucous‐secreting. The observations are discussed in relation to the role of the nasal mucosa in temperature regulation and conditioning of the inhaled air.
Occurrence and Structure of Iron Inclusions in Adipocytes of Larval Lampreys
Authors: Macey D. J. , Youson J. H. 
Published: April 2010

AbstractThe occurrence and structure of adipocytes in the larvae of two lamprey species, Geotria australis and Petromyzon marinus, were examined by electron microscopy. Adipocytes from both species possessed large electron‐dense inclusions which histochemical and energy dispersal X‐ray analyses show as containing iron. The greatest concentration of inclusions in adipocytes was found in the nephric fold of G. australis. While some iron is present in the cytoplasmic matrix as ferritin, the majority is seen in large ammocoetes in membrane‐bound dense aggregations of haemosiderin. The wide variety of inclusion types seen in smaller larvae may reflect on the method of formation of these inclusions within the cell. Because of the high level of iron loading in the larval lamprey nephric fold, this readily accessible tissue may provide a valuable model for studies of iron metabolism in vertebrates.
Localization of Metals in the Gastropod Littorina saxatilis (Prosobranchia: Littorinoidea) from a Polluted Site
Authors: Brough C. N. , White K. N. 
Published: April 2010

AbstractOrgan heavy metal levels, and ultrastructural localization were examined in the marine prosobranch mollusc Littorina saxatilis from a metal‐contaminated site. Copper and zinc are localized in the digestive gland, stomach and kidney. The digestive gland does not appear to be a significant site of iron accumulation. High levels of copper and zinc in the stomach may indicate significant uptake from the food. Relatively high heavy metal levels in several organs were reflected in the presence of a variety of metal‐containing aggregates (granules) within the tissues. In common with other invertebrates two broad classes of granule were present. The first appears to be proteinaceous, with a high sulphur content. This type contained copper and iron and was found in the stomach, kidney, pore cells, and rectum. The second type was inorganic and mineralized, containing phosphorus. They contained calcium, zinc and manganese, and were observed in the kidney and digestive gland. Differences in the number of metals were observed between the various granule types, possibly reflecting specific pathways involved in metal sequestration.
Histology and Ultrastructure of the Cranial Lymphohaemopoietic Tissue in Chimaera monstrosa (Pisces, Holocephali)
Authors: Mattisson A. , Fänge R. , Zapata A. 
Published: April 2010

AbstractIn the present ultrastructural study we have extended previous reports on the histological organization and cell components of the lymphohaemopoietic masses occurring in the cranium, mainly in the orbit, the preorbital canal, and the suprapalatal and coiacoid areas of the holocephalan Chimaera monstrosa. Mature and developing granulocytes, monocytes, macrophages, lymphocytes and plasma cells occur in a reticular and/or fibroblastic supporting stroma inside the cartilaginous skeleton. Heterophils, which are the most abundant granulocytes in the cranial tissue, contain two distinct cytoplasmic granular populations, whereas eosinophils show one uniformly electron dense granule type. Heterophils and eosinophils may differentiate from a common precursor producing granules of each cell type in relation to the activity of rough endoplasmic reticulum and Golgi complex. The presence of macrophages, lymphocytes and developing and mature plasma cells suggests an important role of the cranial lymphohaemopoietic tissue in eliciting the immune responses. A phylogenetical relationship between this tissue and the higher vertebrate bone marrow is proposed on the basis of histological similarities between the cell microenvironments governing haemopoietic differentiation in these organs.
Abnormalities Observed During Spermiogenesis of the RA Mutant of Ceratitis capitata (Diptera, Tephritidae): Cystic Cells
Authors: Báo Sônia N. , Dolder Heidi 
Published: April 2010

AbstractThe ultrastructural study of the RA mutant of the Mediterranean fruit fly, Ceratitis capitata, has been analysed in relation to morphofunctional aspects of the cystic cells. These cells appear to be essential to the normal differentiation of the germ cell and participate actively in the release of mature sperm cells from the cysts. Abnormalities in these cells result in the disorganization of the bundles of spermatic cells, leading to their destruction and elimination, thereby contributing to the diminished fertility of this mutant. Abnormalities of the cystic cells have not yet been reported for any infertile dipteran mutants.
Fine Structure of the Mesothelia and Extracellular Materials in the Coelomic Fluid of the Fin Boxes, Myocoels and Sclerocoels of a Lancelet, Branchiostoma floridae (Cephalochordata = Acrania)
Authors: Holland Nicholas D. , Holland Linda Z. 
Published: April 2010

AbstractThree ontogenetically related coeloms of a lancelet are described by transmission electron microscopy. The fin box coeloms are lined dorsally and laterally by smooth myomesothelial cells of uncertain function. In contrast, there are no myofilaments in the mesothelial cells of the ventral parts of the fin boxes. Similarly, myofilaments are absent from the mesothelia lining all parts of the sclerocoels and the lateral parts of the myocoels (the medial side of the myocoel is a myomesothelium comprising the striated muscles of the body wall). Lancelet coeloms differ from those of other deuterostomes in containing several kinds of formed extracellular materials. All three kinds of coeloms contain distinctive spherules with ramifying processes; dense strands are limited to the myocoels and sclerocoels; and a finely granular secretion is found only at the coelomic surface of the mesothelium lining the sclerocoels. These extracellular materials, which appear to originate from exocytosis of secretory granules from the mesothelial cells, may function biomechanically and for energy storage. The discussion includes a consideration of the so‐called fin rays of lancelets and concludes that none of these structures is homologous with the fin rays of fish.
Two Intracranial Ligaments Supporting the Brain of the Brachiopterygian Fish Polypterus senegalus
Authors: Bjerring Hans C. 
Published: April 2010

AbstractTwo hitherto unknown ligaments that assist in holding the brain in position occur in the brachiopterygian fish Polypterus senegalus. These rounded fibrous cords, placed one behind the other, are called ligamentum intracraniale transversum and ligamentum intracraniale obliquum. The former spans the orbitotemporal division of the cranial cavity and passes through the velum transversum. The latter, which is paired, extends from the roof to the sidewall of the endocranium and runs in the rhombomesencephalic sulcus in company with the trochlear nerve. It is argued that these intracranial ligments, like the spinal denticulate ligaments, are derivatives of a pair of fibrous bands which in early craniate phylogeny extended throughout the length of the neuraxial meninx and enhanced its tensile strength. It is also argued that at least the transverse intracranial ligament was already in existence some 350 million years ago.
On the Pharyngeal Feeding Filter of the Salp Pegea confoederata (Tunicata: Thaliacea)
Authors: Bone Q. , Braconnot J.‐C. , Ryan K. P. 
Published: April 2010

AbstractIn Pegea, scanning electron microscopy of what appear to be the least damaged portions of the filter shows that it has a regular rectangular mesh consisting of thick (100 nm) fibres at right angles to thinner (50 nm) fibres. The rectangular pores of the filter are around 3.3 × 0.57 μm. These measured values from filters that have suffered shrinkage (to an uncertain degree) during preparation are considered to indicate that the actual pore size in life is some 4.0 × 0.7 μm. The mucous‐net feeding filter of salps differs from that of other tunicates since flow through it results from muscular activity. Calculations based on the estimated pore size and filtering rate suggest that during part of the filtering cycle, the pressure drop across the filter is considerably greater than that across other tunicate mucous‐net filters.
The Morphology and Periodic Structures of the Otolith of the Chinook Salmon (Oncorhynchus tshawytscha), and Temperature‐dependent Variation in Otolith Microscopic Growth Increment Width
Authors: Gauldie R. W. 
Published: April 2010

AbstractThe otolith (sagitta) of the chinook salmon (Oncorhynchus tshawytscha) has a variable external crystalline morphology which is related to differences in the growth rate of crystals in different parts of the otolith. The internal crystal structure of the otolith is complex with different mineral phases in different growth fields of the otolith and a well‐defined series of microscopic growth increments in both the dorsal and the ventral parts (orientation in situ) of the otolith. The period of the microscopic growth increments was shown, by both a rearing experiment and interpolation from fish of known age, to be daily. By rearing sibling chinook salmon at different temperatures (while still maintaining them on the same diet) it was shown that the width of the daily growth increment varies with temperature, but neither multi‐ nor sub‐daily increments appear in the area of regular, daily growth incrementation. Inclusions of the vaterite morph of calcium carbonate crystallizing in the botryoidal habit occur in the otherwise aragonitic otolith. Regularly spaced check rings in the sulcul part of the otolith are homologous with those occurring in the dorsal and ventral growth axis and are. on average, separated by about 28 microincrements.
Structure and Some Contractile Properties of Musculus Iliofibularis of Agama stellio stellio
Authors: Abu‐Ghalyun Younes 
Published: April 2010

Abstract The running speed of Agama stellio stellio was 2.1 ± 0.3 m s−1 at preferred body temperature (Tb, 30°C). To account for sprint locomotion, we meaured two mechanical parameters and examined the ultrastructural features of a major locomotory muscle in normal walking and running locomotion, the iliofibularis muscle, which is considered to act as an extensor of the lower hind limb. The time to peak isometric twitch tension and time to half relaxation were 52 ± 7 ms and 76 ± 5 ms, respectively.The comparative ultrastructure of the fast and slow fibes provides structure‐to‐function correlation. The sarcoplasmic reticulum and T‐tubules system are abundant in fast fibres which serve to transmit Ca2+ and spread the excitatory impulse intracellularly with great rapidity. In contrast, the membranous system of slow fibres is relatively poor and this indicates slow impulse propagation. Thus, these results show that the fast locomotion of Agama stellio stellio can, in part, be explained by the physiology and ultrastructure of the fibres of the locomotory muscles.
Accessory Escal Gland (AEG) in Some Deep‐sea Anglerfishes
Authors: Munk Ole 
Published: April 2010

AbstractA hitherto unknown escal gland not associated with the escal light gland has been found in some ceratioid fishes (Ceratias holboelli, C. uranoscopus, C. tentaculatus, and Phyllorhinichthys micractis). This so‐called accessory escal gland (AEG) is situated in the connective tissue around the illicium and part of the escal light gland. The presence of ducts opening on the surface of the esca shows that the AEG, like the escal light gland, is derived from the epidermis. The function of the AEG is unknown. Its location suggests that it may in some way supplement the escal light gland, for example, by secreting substances yielding a scent that may attract prey animals.
Intestinal Ultrastructure of Nerita picea (Mollusca: Gastropoda), an Intertidal Marine Snail of Hawaii
Authors: Pfeiffer Carl J. 
Published: April 2010

AbstractThe neritid snail Nerita picea is a marine prosobranch mollusc which resides high in the intertidal zone on the Hawaiian Islands. Since other studies have shown considerable variations in molluscan gut histology and the relatively few recent ultrastructural reports have revealed novel cellular structures in the molluscan gastrointestinal tract, this investigation was directed toward ultrastructural clarification of the neritid intestine.Seven principal cell types constituted the intestinal architecture, including absorptive cells, zymogen cells, neural and endocrine cells, myocytes, pigment and gland cells. The intestinal epithelium was composed mainly of tall ciliated (9 plus 2 complement of microtubules) columnar absorptive cells which also possessed microvilli, extensive deposits of non‐membrane‐bound lipid‐like droplets, and large reservoirs of glycogen‐like granules. Less frequent, columnar zymogen cells contained numerous large zymogen secretory granules and possessed microvilli but not cilia. Small endocrine‐like cells with secretory granules were observed basolaterally between some absorptive cells, resembling mammalian gut endocrine cells. Nerve fibers were prevalent in close association with the epithelial cells. A thin layer of non‐striated muscle was present, as well as a serosally located gland composed of storage cells with a granular matrix and large granules.
A Systematic Survey of the Occurrence of the Hypothalamic Saccus Vasculosus in Teleost Fish
Authors: Tsuneki Kazuhiko 
Published: April 2010

AbstractThe saccus vasculosus (SV) was examined histologically in more than 200 species of teleosts. The Atherinomorpha (Cyprinodontiformes and Atheriniformes) completely lack the SV. Many primary freshwater teleosts (Osteoglossiformes, Cypriniformes, Characiformes, Siluriformes, Gymnotiformes, and Synbranchiformes) possess none or a reduced SV. Some secondary freshwater teleosts also possess a reduced SV, but other secondary freshwater teleosts have a well‐developed SV. Some marine teleosts swimming in the surface water, for example, the Clupeiformes and Scombridae, possess a somewhat reduced SV. Bathypelagic teleosts also possess a rather reduced SV. On the other hand, most marine teleosts, benthic or nektonic in the subsurface water, have a well‐developed SV. The examples are the Anguilliformes, Scorpaeniformes, Perciformes, Pleuronectiformes, and Tetraodontiformes. Since all non‐teleostean actinopterygians possess a well‐deveoped SV, it is assumed that the earliest teleosts also possessed a SV. In the course of adaptive radiation, some teleost groups certainly have reduced or lost the SV while others developed it to various degrees. Reduction or development of the SV might be influenced more easily by environments in certain groups and might be constrained more strongly by phylogenetic lineages in other groups.
The Electrosensory Cells of the Ampullary Organ of the Transparent Catfish (Kryptopterus bicirrhus)
Authors: Jørgensen J. Mørup 
Published: April 2010

AbstractAn easy method to demonstrate epidermal sensory organs is described. With the dye Daspei, sensory cells as well as their nerves are visible in the fluorescence microscope. Actin filaments in pore cells and sensory cells are demonstrated with rhodamine‐labelled phalloidin, and the distribution of microtubules is described after fixation in albumin‐osmium tetroxide‐glutaral‐dehyde fixation.
Ultrastructure and Development of the Eyes of Larval Kronborgia isopodicola (Platyhelminthes, Fecampiidae)
Authors: Watson N. A. , Williams J. B. , Rohde K. 
Published: April 2010

AbstractThe structure and development of the paired eyes of the larva of Kronborgia isopodicola were studied by electron microscopy. Each ocellus, located anterolateral to the brain, is of the inverse rhabdomeric type. A supportive cell contains 10–12 rows of concentrically arranged crystalline plates forming a cup‐shaped reflective structure (mirror), the opening of which faces laterally. Three large dendritic processes penentrate the opening and each terminates in a rhabdomere. The cell body of each dendrite lies slightly behind the margin of the mirror cell. Cytoplasmic extensions of the supportive/mirror cell project across the opening, interposing between the dendritic processes. A secretory process (possibly neurosecretory) passes in front of the eyecup in contact with dendritic processes and the extensions of the supportive cell. Reflective layers consisting of rows of crystalline platelets are widely distributed in the animal kingdom, but among the Platyhelminthes this type of reflective ocellus has previously been reported only from Polystomatidae (Monogenea).
The Ultrastructure of the Spermatozoa of Three Species of Myobatrachid Frogs (Anura, Amphibia) with Phylogenetic Considerations
Authors: Lee Michael S. Y. , Jamieson Barrie G. M. 
Published: April 2010

AbstractComparison of the spermatozoa of three genera of limnodynastines (Myobatrachidae: Anura) with those of 42 other species of frogs (in 11 families) previously examined allows the following phylogenetic inferences. The bufonoid neobatrachians (corresponding with the Arcifera of some classifications) form a monophyletic assemblage which is characterized by the possession, unique for the Anura, of a conical perforatorium; the rod‐like perforatorium, which is plesiomorphic for tetrapods, is absent. Of the taxa investigated, the myobatrachids appear to be the sister‐group of the remaining bufonoids, here termed eubufonoids (leptodactylids, rhinodermatids, hylids, and bufonids). The spermatozoa of the myobatrachids Limnodynastes, Neobatrachus, and Mixophyes are very similar to each other despite extremely varied fertilization biology. Symplesiomorphies for the Anura which they exhibit include the conical acrosome with subacrosomal material, the elongate, cylindrical nucleus, single flagellum and, paralleling this, an undulating membrane which is supported by a longitudinal element, the axial (major) fibre, the latter being accompanied in the midpiece by mitochondria. A myobatrachid synapomorphy appears to be the presence of a periaxial sheath enclosing the axial fibre of the flagellum. Forward extension of the axial fibre into the centriolar fossa in myobatrachids is seen elsewhere only exceptionally (in the bufonid Nectophrynoides). Bufonids, and most other eubufonoids including leptodactylids, differ apomorphically from Limnodynastes, and Neobatrachus in location of the mitochondria at the axonemal end (and in a collar) rather than the axial fibre end of the undulating membrane. In Mixophyes, mitochondria surround the nuclear‐axonemal junction in a cytoplasmic droplet and are probably shed with this at maturity.