bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light‐ and Electronmicroscopic Observations on the Blood Cells of the Atlantic Hagfish, Myxine glutinosa (L.)
Authors: Mattisson Artur G. M. , Fänge Ragnar 
Published: April 2010

AbstractIn the blood of Myxine glutinosa three cell lines may be distinguished: erythrocytes, granulocytes and agranulocytes. The erythrocytes are remarkably large, oval and nucleated. They are well defined in all their developmental stages by a characteristic micropinocytosis. They originate from blast cells which proliferate in the circulating blood. The blast cells probably form from agranulate stem cells of the intestinal myeloid tissue. The granulocytes constitute about half of the leucocytes. They are neutrophilic with a lobated nucleus. The granulocytopoiesis takes place in the intestinal myeloid tissue. The agranulocytes mainly include two cell types, termed spindle cells and lymphocyte‐like cells. These cell types, however, transform into each other. Macrophages occur essentially in the peritoneal cavity rarely in the blood. Transition forms between macrophages and granulocytes may exist. The blood also contains cells which on morphological grounds have been termed thrombocytes. Whether these cells are identical with those necessary for clotting of the blood remains to be proved. With the exception of erythroblasts, the different lines of blast cells are difficult to identify and distinguish from each other. Possibly all lines of blood cells originate from agranulate lymphocyte‐like stem cells, most of which are produced by the intestinal myeloid tissue.
Structure of Adnate Colony Portions in Crisiidae (Bryozoa Cyclostomata)
Authors: Silén Lars 
Published: April 2010

AbstractThe “rhizoidsrdquo; surrounding the base of the erect “colony” emanating from the ancestrula in the Crisiidae, especially the simple species Crisidia cornuta (L.), are a regular adnate system of autozooids. Each autozooid is composed of a proximal adnate part and a distal peristome (in some species kenozooids are possibly intercalated). The autozooid peristomes support erect branches identical in budding and structure with the branch emanating from the erect peristome of the ancestrula. Thus, the complete crisiid colony consists of an adnate system of ancestrula and autozooids, which form erect branches from their peristomes. The adnate zooid system is comparable in autozooid morphology and budding pattern with simple uniserial stomatoporids. The tentative hypothesis is proposed that the crisiid group has developed from primitive stomatoporids; the adnate zooid system of the stomatoporids apparently evolved peristomial budding to produce the erect colony branches characteristic of crisiids.
Functional Anatomy of the Olfactory Organ of Fish and the Ciliary Mechanism of Water Transport
Authors: Døving Kjell B. , Dubois‐Dauphin Michel , Holley André , Jourdan François 
Published: April 2010

AbstractThe olfactory organ of tench is functionally divided in a vestibule and a gallery. Experimental observations are presented indicating that an unidirectional watercurrent is created from the vestibule to the gallery via the corridors which are formed by the leaves of the olfactory rosette. The conditions for creating the watercurrents are: oriented and symmetrical beats of cilia situated on the walls of the corridors, and appropriate spacing of the corridors. This principle for water sampling is found in the olfactory organs of trout, carp, roach, catfish, eel, rockling and dogfish. In some other fishes studied the olfactory organs have accessory olfactory sacs and there is no subdivision in vestibule and gallery. In these organs the watercurrents are achieved by a pumping mechanism of the sacs.
The Epidermal Structures of the Tongue and the Buccal Cavity of the Brahminy Myna (Sturnus pagodarum Gmelin) and the Wagtail (Motacilla flava thunbergi Billberg)
Authors: Dubale M. S. , Thomas V. C. 
Published: April 2010

AbstractA study of the epidermal structures of the buccal cavity and the tongue of two passerine birds, the brahminy myna (Sturnus pagodarum Gmelin) which feeds on insects, fruits etc. and the grey‐headed yellow wagtil (Motacilla flava thunbergi Billberg) which is solely an insectivorous bird was conducted with the help of light and scanning electron microscopes. The studies revealed the presence of spines and scales on the buccal roof and the tongue of both the birds. However, the brahminy myna carried spinelets over the spines and ultra fine hairy structures on the inner margins of the bifid region of the tongue. There were no spinelets over the spines of the wagtail but the surface was covered with numerous scales.
Feinstruktur der Knochenzellen in dem Gonopodium von Heterandria formosa Agassiz, 1853 (Teleostei, Poeciliidae)
Authors: Riehl Rüdiger 
Published: April 2010

AbstractOsteocytes, osteoblasts and osteoclasts were recognized. The osteocytes lie in a thin zone inside of the basement membrane. The development of the rough endoplasmic reticulum indicates the presence of both active and inactive osteocytes. The spindle‐shaped osteoblasts synthesize the collagen fibrils of the preosseous matrix and are more frequent than the osteocytes. The elongated osteoclasts are rare.
Blood Cell Ultrastructure of the Ascidian Botryllus schlosseri L. II. Pigment Cells
Authors: Burighel Paolo , Milanesi Carla , Sabbadin Armando 
Published: April 2010

AbstractColonies of Botryllus schlosseri L., bred in the laboratory and genetically selected as regards the blue and/or reddish pigments, were used. The following phenotypes were investigated under the electron microscope: (a) blue colonies without reddish pigment; (b) reddish colonies without blue pigment; (c) colonies with both blue and reddish pigments; (d) colonies with neither blue nor reddish pigments. In the pigmented colonies, a specialized blood pigment cell type was recognized that, in giant membrane‐limited vacuoles, contained a great number of granules. In general, the granules were similar in size, not individually limited by a membrane and were made up with electrondense material often arranged in concentric rings. Although there could be some variability within the same cell, in each phenotype the granules displayed a characteristic pattern so that the differences in colour of the granules, as seen in vivo, were paralleled by differences in the ultrastructural architecture. In the unpigmented colonies also, granulated vacuolar cells, rare in number but morphologically comparable to the pigment cells, were seen.On the basis of these results, the hypothesis of the existence of a prospective pigment cell and of a common origin for all the pigment cells of B. schlosseri is discussed.
An Ultrastructural and Fluorescence Histochemical Study of the Myenteric Plexus of the Stomach of the Rainbow TroutSalmo gairdneri
Authors: Santer Robert M. , Holmgren Susanne 
Published: April 2010

AbstractThe myenteric plexus of the rainbow troutSalmo gairdneriis enclosed within an incomplete Schwann‐like sheath which allows bundles of unmyelinated axons to pass into the adjacent smooth muscle layers. Neuronal and non‐neuronal constituents of the myenteric plexus are divided into smaller units by endoneurial collagen which in places condenses to form a perineurial covering. The myenteric plexus is avascular but arterioles and fenestrated capillaries are present close to the plexus in the intermuscular space. Small groups of neurones constitute the ganglia of the plexus but as yet few ultrastructural indications of differing neurone types have been observed. Within the neuropil of the ganglia five types of axon profile, characterised by their vesicle content, have been identified. One of these types was only recognisable following the administration of 5‐hydroxydopamine. Axo‐somatic and axo‐dendritic synaptic contacts were only made by Type 1 axons but these were uncommon. The presence of an adrenergic component of the myenteric plexus was confirmed ultrastructually following 6‐hydroxydopamine‐induced degeneration and also by Falck‐Hillarp fluorescence histochemistry which revealed an extensive distribution of adrenergic nerves in the plexus. The structural organisation of the plexus, the comparatively few ultrastructurally recognisable axon and neurone types and the sparsity of synaptic contacts all indicate that the teleost myenteric plexus is less complex than its mammalian counterpart.
Cerebral Neurosecretory Cells in the Millipede, Archispirostreptus syriacus, De Saussure (Diplopoda, Spirostreptiadae)
Authors: Warburg M. R. , Rosenberg Mira 
Published: April 2010

AbstractThe brain of the millipede, Archispirostreptus syriacus, was studied for its neurosecretory cells. Using standard cytochemical techniques, 2 types of neurosecretory cells could be identified. One of these cells could also be identified with the EM. In addition, three different cells were also observed in the EM and contained secretory granules of various sizes. Altogether, five neurosecretory cell types have been observed in the cerebral mass of this millipede.
Mechanisms of Defensive Stridulation in the Bushcricket Mygalopsis marki Bailey (Copiphorini, Tettigoniidae)
Authors: Bailey Winston J. , Sandow John D. 
Published: April 2010

AbstractThe copiphorine tettigoniid Mygalopsis marki uses two acoustic defensive displays which are quite distinct from the tegminal stridulatory mechanism. Both adults and nymphs utilise a stridulation produced within the head capsule. Observation and simple experiment reveal that this sound is produced in conjunction with the passage of air into the buccal cavity. There are large trachea beneath the frons which may be associated as amplifiers of these noises. The hind wings of the adults have small downward projecting spines set in open membranous areas of the wings. When the insect is excited, these spines engage a highly specialised area of the cuticle on the dorsal terga. The production of the noise requires only slight movement of the abdomen. Its role in defense is discussed.
Fine Structural Observations on the Turbellarians Stenostomum sp. and Microstomum lineare with Special Reference to the Extracellular Matrix and Connective Tissue Systems
Authors: Pedersen Knud Jørgen 
Published: April 2010

AbstractEmploying transmission electron microscopy, observations were made on epidermis, muscle cells and connective tissue systems, with special emphasis on extracellular matrix components (ECM), in two rather primitive turbellarians: Stenostomum sp. (Catenulida) and Microstomum lineare (Macrostomida). In Stenostomum the only ECM components found are basal laminae, predominantly situated subepidermally. In Microstomum ECM is well developed and connective tissue filaments abundant in conspicuous extracellular spaces. It is uncertain whether basal laminae exist. The finding of basal lamina structures as the only ECM component present in Stenostomum makes it now possible to establish a complete ECM and connective tissue hierarchy in turbellarians, ranging from a purely cellular type with no ECM present to systems dominated by ECM and very similar to loose connective tissue in vertebrates. Comparative aspects of ECM and connective tissue systems in turbellarians are discussed in addition to the difficulties and ambiguities regarding definition and nomenclature of basal matrices as basal laminae and subepidermal membranes.
Amoebocytes in the Lining of the Body Cavity and Mesenteries of Priapulus caudatus (Priapulida)
Authors: McLean Norman 
Published: April 2010

AbstractNuclei associated with membranes lining the body cavity in Priapulus caudatus are shown by electron microscopy to be the nuclei of amoebocytes. The membranes themselves are not cellular and do not constitute a peritoneum. Mesenteries, present in the body cavity, also are not cellular; amoebocytes occasionally are found within them. These findings weaken the idea that priapulids are coelomates, although unequivocal proof that priapulids are pseudocoelomates would require a fine structural study of the early developmental stages.
Fine Structure of The Paratympanic Organ in the Avian Middle Ear
Authors: Jørgensen J. Mørup 
Published: April 2010

AbstractLight and electron microscopical examination of the paratympanic organ of 8 avian species reveals a sensory epithelium with hair cells and supporting cells, covered by a gelatinous cupula with numerous non‐crystalline deposits. The position of the organ is in agreement with previous suggestions of its function as an air pressure detector.
A Comparative Study of the Aminergic Structures in the Hypothalamus and the Hypophysis of Amphibian Larvae, with Special Reference to the Innervation of the Pars Distalis
Authors: Aronsson Stig 
Published: April 2010

AbstractThe distribution and occurrence of the aminergic structures of the hypothalamus and the hypophysis of the investigated species are very similar, except for the pars distalis. In the tadpoles of the anuran species Rana temporaria, R. arvalis, R. dalmatina, R. escutenta, Bufo bufo and B. calamita, the pars distalis is aminergically innervated (the Falck‐Hillarp technique), but these nerves disappear at the metamorphic climax. In the larvae of the urodelan species Triturus cristatus and T. vulgaris, the pars distalis is devoid of such nerves. Electron microscopical studies of R. temporaria, B. bufo and T. cristatus confirm these observations. A discussion of the functional significance of the pars distalis nerves and the phylogenetic role of the difference between anuran and urodelan species is given.
Secretin‐like Immunoreactivity in the Neural Complex of a Protochordate
Authors: Pestarino Mario 
Published: April 2010

AbstractBy means of immunocytochemical methods, a secretin‐like immunoreactivity is demonstrated in the neural complex of the ascidian Styela plicata. Secretinergic neurons are localized in the cortex of the cerebral ganglion and numerous secretin‐like immunoreactive cells are detected in some lobules of the neural gland. The possible functions of secretin‐like substances in the ascidian neural complex are discussed.
Anatomical and Histological Investigations on the Caudal Skeleton of Apteronotus leptorhynchus (Apteronotidae, Gymnotoidei)
Authors: Meunier François Jean , Kirschbaum Frank 
Published: April 2010

AbstractThe caudal skeleton of Apteronotus leptorhynchus was studied at various stages from hatching to the adult stage using anatomical and histological techniques. The caudal skeleton that supports the lepidotrichia is reduced to a rhomboid caudal plate (caudal cartilage) that extends the vertebral axis. This cartilage appears for the first time in 8 day old fish, postero‐ventral to the notochord. During its growth, perichondral and endochondral ossification occurs, beginning at the anterior end of the cartilage. Comparison with the anatomy and ontogeny of the typical caudal skeleton of teleosts allows us to interpret the caudal cartilage of A. leptorhynchus as an hypuro‐opisthural component that is homologous to the cartilage that occurs at the tip of the axial skeleton in Eigenmannia virescens.
Effect of 17 α‐Methyltestosterone on the Cytology of the Pituitary and the Liver, and on Plasma Electrolytes in Male Silver Eels
Authors: Olivereau Madeleine , Olivereau Jacqueline 
Published: April 2010

AbstractMale silver eels kept in fresh water were injected with 17α‐methyltestosterone (MT). They received 5, 10, 15 or 20 injections (8 μg/g every other day) or 6 or 9 injections (4 μg/g or 2.5 μg/g once a week). Compared to solvent‐injected controls, the treated eels showed changes in the pituitary: prolactin, corticotropic, thyrotropic and melanotropic cells were stimulated. Gonadotropic cells had enlarged nuclei, but synthesis and storage of granules and large globules were not evident, despite the progressive testicular maturation. High doses of MT induced a liver hypertrophy, a drop in plasma osmolarity and sodium level. An increase in plasma calcium level is possibly involved in the reduced activity of PAS‐positive Ca‐sensitive cells of the pars intermedia. These responses, previously observed in estradiol (E2) treated eels, may suggest that MT is aromatized in the brain and/or the pituitary. However, the considerable stimulation of GTH cells which always occurs in E2‐treated eels is absent in MT‐treated eels. With lower doses of MT, changes in the pituitary and the testis were similar to those produced by high doses, although the Ca‐sensitive cells were more active. The decrease in plasma osmolarity and sodium level was less marked, plasma calcium was slightly reduced and the liver was not modified. There is no clear evidence in favour of E2 production. These data suggest that MT may stimulate the gonad directly, in agreement with biochemical data by Dufour et al. (1983).
Capillary Distribution in the Lateral Muscle of Axolotl (Ambystoma mexicanum Shaw)
Authors: Totland Geir K. 
Published: April 2010

AbstractThe vascular supply of red, intermediate and white fibres in the axial muscle of axolotl (Ambystoma mexicanum Shaw) was visualized with Indian ink‐injections and quantified with morphometrical methods on semithin sections.Red fibres were surrounded by 1.4 ± 0.6 capillaries (mean + SD), the intermediate fibres by 1.2 ± 0.9 capillaries and white fibres by 0.3 ± 0.6 capillaries. The mean vascularized surface area per unit volume of fibre was 0.0159, and 0.0068 and 0.0007 (μm2/μm3) for red, intermediate and white fibres, respectively. A unit volume of mitochondria within each type of fibre was supplied by 0.15, 0.17 and 0.08 μm2 vascularized surface for red, intermediate and white fibres, respectively. This indicates that there exist a good balance between oxygen demand represented by mitochondrial content and oxygen supply represented by the vascularized surface.
Relations Between Hibernation and Ovarian Functions in a Temperate Zone Frog, Rana temporaria
Authors: Jørgensen C. Barker 
Published: April 2010

AbstractAdult female frogs were exposed to artificial hibernation in a refrigerator, at about 1–3°C, 1–2 months earlier than in nature, isolated or together with males. Ovarian functional state at the beginning of hibernation was assessed from ovarian biopsies taken in mid‐September. All frogs ovulated during hibernation which was interrupted in mid‐May, but in seven out of 19 frogs ovulation was incomplete. The number of non‐ovulated oocytes varied from a minor fraction to about two thirds of the complement of vitellogenic oocytes, indicating that the follicle size reached at the time of induced hibernation was at the critical level for successful maturation. This critical size was about half the normal oocyte volume at the onset of natural hibernation. There was no vitellogenic growth during hibernation, which presumably constitutes the period of follicle maturation. In five of the frogs, oogenesis sensu stricto had occurred during the period of hibernation, some oogenic events being completely finished at autopsy in mid‐May and others still progressing.
Effect of Fat Body Excision in Female Bufo bufo on the Ipsilateral Ovary, with a Discussion of Fat Body‐Gonad Relationships
Authors: Jørgensen C. Barker 
Published: April 2010

AbstractComplete removal of a fat body in female toads did not affect the oocyte populations of the ipsilateral ovary with intact blood circulation. It is argued that the inverse relationship in development typical of amphibian fat bodies and gonads does not reflect direct functional relations between the two organs, but may express shifts in anabolic patterns with the onset of sexual maturation.
The Nutrimentary Egg Development of the Mite, Varroa jacobsoni (Acari, Arachnida), an Ectoparasite of Honey Bees
Authors: Alberti Gerd , Zeck‐Kapp Gabriele 
Published: April 2010

AbstractThe fine structure of the female gonad of Varroa jacobsoni is described. There are two components: the ovary proper and the so‐called lyrate organ. The ovary is the place where oocytes mature, embedded in a supporting tissue composed of two cell types: somacells 1 and somacells 2. The lyrate organ has a nutrimentary function and is comprised of two components: supporting cells and nutritive tissue. The supporting cells are similar to the somacells 2 in that they contain abundant microtubules. The nutritive tissue is an extensive syncytium. It is connected with the oocytes via intercellular bridges, the nutritive cords. Oocytes and nutritive tissue are thought to have derived from common stem cells. From fine structural evidence it is concluded that ribosomes are one of the most important components to be transported via the nutritive cords into the oocytes. However, an increase in number of mitochondria in the middle‐stage oocytes may also be a consequence of transport of these organelles from the nutritive tissue into the oocytes. Further characteristics make plausible that the interdependences of oocytes and nutritive tissue are comparable to those found in meroistic ovarioles of insects. The somatic components do not seem to be as important as the follicle cells of insects, however. It is assumed that the evolution of a nutrimentary oogenesis speeds up embryogenesis. Thus, the differentiation of the female gonad of Varroa jacobsoni may have facilitated the species' adaptation to a development completed in a short and limited time within the shelter of the covered brood cell of the bee.
Cardiac Function in the Hagfish, Myxine (Myxinoidea:Cyclostomata)
Authors: Satchell Geoffrey H. 
Published: April 2010

AbstractThe electrocardiogram of Myxine glutinosa is described and its events related to systole in the sinus venosus, atrium and ventricle. Intraatrial, ventricular, ventral aortic and dorsal aortic pressures are presented. Ventricular systolic pressure was 10.3 ± 2.0 cm H2O; average dorsal aortic pressure was 7.0 ± 1.7 cm H2O. The resistance of the gill vessels caused a loss of 28% of the ventral aortic pressure. The conclusion is drawn that the basic mechanism of the heart of Myxine is like that of fish and higher vertebrates, and that the low pressure it develops is to be ascribed to structural and functional features of the myocardium.
The Wheel Organ and Hatschek's Groove in the Lancelet, Branchiostoma lanceolatum (Cephalochordata)
Authors: Sahlin Karin , Olsson Ragnar 
Published: April 2010

AbstractThe wheel organ is a specialized epithelium in the roof and sides of the adult lancelet oral cavity. It borders the oral epithelium proper, separated by a thin strip of margin cells which are not ciliated but contain a few large dense‐cored vesicles apically. The wheel organ cells are tall and strongly ciliated and have dark, heterochromatin‐rich nuclei. Dorsally, and slightly paramedially, the organ is further specialized, forming the so‐called Hatschek's groove (pit), which consists of two ciliated cell types. The first type synthesizes a dense granular material, the granules being approximately 95 nm in diameter. This is stored basally and apparently it is also released through the basal cell membrane into the blood cavities. The cells at the bottom of Hatschek's groove have peculiar rod‐shaped apical cellular regions. Each cell bears one tall cilium surrounded by microvilli and it is apparently involved in the production of secretory material into the groove. It is evident that the histology, and probably also the function, of the wheel organ and its groove is much more complex than hitherto believed.