bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyse du caryotype de cinq espèces de planaires par la méthode du choc hyp otonique
Authors: Dutrillaux B. , Lenicque P. 
Published: April 2010

AbstractAn air drying method for karyotype analysis of Planarian worms is described. Five species are analysed (D. lugubris, D. tigrina, D. gonocephala, C. alpina and P. felina).Some differences and similarities are detected, both in quantitative and qualitative respects. All the chromosomes can be clearly identified. The haploid number ranges from 4 to 9. An attempt to tackle the difficult problems of phylogenic aspect, and chromosomal variation in the somatic cells of D. gonocephala, is presented.RésuméLes auteurs présentent une technique d'analyse du caryotype des Planariidae, par choc hypotonique.Les caryotypes de 5 espèces (D. lugubris, D. tigrina, D. gonocephala, C. alpina et P. felina) sont décrits et comparés.Des différences et des analogies sont ainsi mises en évidence dans le genre Dugesia, où une étude phylogénique est ébauchée.Le problème de la variation chromosomique des lignées somatiques, chez D. gonocephala est envisagé.
Light Microscopy of Living Neurosecretory Cells of the Corpus cardiacum of Schistocerca gregaria
Authors: Krogh I. M. 
Published: April 2010

AbstractDesert locust corpora cardiaca have been treated with hydrolytic enzymes in saline solution in order to facilitate separation of individual intrinsic cells. Some of the enzymes digested the basal lamina covering the corpus cardiacum, and also the intercellular cementing substance. Living neurosecretory cells with axonal projections could be isolated and observed by phase contrast microscopy or by darkfield illumination. By morphological criteria the secretory cells should be characterized as neurons, and two different types of secretory neurons have been identified. Brownian movement of cytoplasmic particles occurs in damaged cells and is regarded as a post mortem phenomenon.
The Origin of the Chordates
Authors: Jollie Malcolm 
Published: April 2010

AbstractThe study of development and comparisons of the adult structures of the several groups of protochordate animals reveals something of their interrelationships and origin. The hemichordates are perhaps closer to the echinoderms than to the chordates, but these groups appear to have been derived from a bilaterally symmetrical dipleurula ancestor, not from a sessile pterobranch‐like form. The origin of the chordates is speculative but the idea of a prototunicate stage is rejected. The tunicate is viewed as a highly modified end product, with fewer similarities to the ancestral form than amphioxus. Amphioxus is quite suggestive of the vertebrate, yet it is more like the tunicate in the details of its embryology and along with that rather extreme peripheral group is best thought of as constituting a subphylum, the Acraniata.The idea of the early vertebrate as a filter feeder must be rejected since it is assumed here that perfection of that function led to a sessile or inactive way of life (as in the acraniates or lamprey larva) and failed to lead to the active creature with highly developed sensory, neural, and locomotor systems identified here as the protovertebrate. Further, the muscular plastic pharynx and moveable mouth of the protovertebrate suggest feeding on larger organisms, predation, and the abandonment of ciliary water‐current feeding.
The Spermatozoon of Siboglinum (Pogonophora)
Authors: Franzén Åke 
Published: April 2010

AbstractThe spermatozoon and some spermatid stages of Siboglinum (Pogonophora) have been examined by light and electron microscopy. In the spermatozoon a helical acrosome, a helical nucleus and a “body” with axonema follow each other in normal sequence. Head and tail are joined by a very short neck region containing two modified centrioles. The posterior portion of the nucleus is surrounded by a mitochondrial sheath consisting of three tightly wound mitochondrial helices. In the main portion of the tail the 9+2 unit is sorrounded by a granular sheath of dense material. In the neck region a centriole adjunct develops into a dense substance containing about nine rods.At an early stage, when the centriolar apparatus and flagellum become associated with the nucleus, three large mitochondria with fairly regular cristae are seen at the base of the nucleus. A well developed Golgi apparatus is present in early stages. Rows of microtubules are observed encircling the spermatid nucleus.Compared with the primitive type of spermatozoon the pogonophore sperm shows elongated and specialized nucleus, acrosome and mitochondria. It is concluded that the ancestral form must have had a fairly primitive spermatozoon and that evolution has proceeded towards a modified sperm with complicated spiral structure in connection with the evolution of a modified biology of fertilization, viz. specialized spermatophores. It is not known how the spermatophore discharges the spermatozoa nor how the spermatozoa find their way to the eggs. Two kinds of sperms are produced in the gonads of Siboglinum. The atypical sperm is smaller than the typical one.
Scanning Electron Microscopic Observations of the Mesenchyme Cells in the Larvae of the Starfish Pisaster ochraceus
Authors: Chia Fu‐Shiang 
Published: April 2010

AbstractThe are two morphological types of mesenchyme cells, bipolar and multipolar, and both are derived from the tip of the archenteron at the gastrula stage. Some of the cells form larval muscle and others may be involved in the stomodeum and coelomic pouch formation.
Relation Between Testosterone Levels in Serum and Proteolytic Activity in the Neck Muscles of the Norwegian Reindeer (Rangifer tarandus tarandus)
Authors: Lund‐Larsen Tata Ringberg 
Published: April 2010

AbstractThe characteristic hypertrophying of the male reindeer neck muscles during the rutting period, which coincides with the rise in serum testosterone levels, is found to be accompanied by a significant decrease in lysosomal proteolytic activity of the neck muscle cells.Conversely, during the period of neck muscle involution following the rapid decline in serum testosterone after the rut, a marked increase in neck muscle proteolytic activity is found. These changes in lysosomal activity do not parallel the changes in feed consumption and nutritional stage of the animals during the rutting period. The lysosomal proteolytic activity of the male reindeer neck muscles thus may be, at least partly, under the control of sex steroid hormones.
Ultrastructure of the Respiratory Epithelium in the Lungs of the Newt Triturus cristatus
Authors: Meban Cowan 
Published: April 2010

AbstractThe respiratory epithelium in the lungs of the newt Triturus cristatus has been studied by electron microscopy. The entire pulmonary gas‐exchange area is covered by a continuous epithelium, the cells of which are all of the same type and are termed “pneumonocytes”. Typically each pneumonocyte is squamous and has attenuated sheets of cytoplasm which cover the pulmonary capillaries. Its free surface bears microvilli while mitochondria, multivesticular bodies and small inclusions are prominent in its cytoplasm. Many pneuomonocytes send cytoplasmic processes deep into the substance of the lung wall. It is postulated that these processes may help to anchor the epithelium.
Chromosome Number of Cidaris cidaris (Cidaridae, Echinoidea)
Authors: Colombera Dario , Vitturi R. , Zanirato L. 
Published: April 2010

AbstractThe diploid number 44 has been determined, with reserve, for the echinoid Cidaris cidaris, thus further supporting the hypothesis that the phylum Echinodermata is characterized by an astonishing stability of chromosome numbers. The spermatogonial chromosomes of C. cidaris are very minute and heterocyclic elements are absent.
Cyclical Changes in the Testis of the Hagfish Eptatretus burgeri (Cyclostomata)
Authors: Patzner Robert A. 
Published: April 2010

AbstractThe development of the spermatogenetic stages in the testis of the hagfish Eptatretus burgeri was studied by means of histological techniques. These animals have an annual reproductive cycle with a spawning season in October. Spermatocytes begin to appear in January and reach a maximum in March. The development of spermatids of stage I and stage II starts in April and June, respectively. In August about 35% of the testicular follicles contain spermatids of stage II. The gonadosomatic index shows a more or less constant increase from November until August. During the spawning season, no animals with well developed testis could be trapped. About 10% of male hagfish bear undeveloped gonads.
The Fine Structure of the Echinoderm Cuticle and the Subcuticular Bacteria of Echinoderms
Authors: Holland Nicholas D. , Nealson Kenneth H. 
Published: April 2010

AbstractA cuticle, consisting of fibrous and sometimes granular material, covers the epidermal cells of crinoids, echinoids, asteroids, ophiuroids and holothurians. The tendency for the echinoderm cuticle to dissolve during fixation in phosphate‐buffered glutaraldehyde accounts for several previous reports that echinoderms have no cuticle. Depending on the species, there are from one to three cuticular sublayers. Abundant epidermal microvilli penetrate the cuticle of crinoids, echinoids and asteroids, but such microvilli are rare in ophiuroids and holothurians. The ophiuroid cuticle is especially modified, since numerous pinched‐off tips of microvilli are included in its outer layer, and its inner layer may be very thick. The discussion includes speculations on cuticle evolution, with special reference to the deuterostomes. Each echinoderm studied, except the two holothurians, harbors one or two morphological types of bacteria between the cuticle and the epidermal cells and/or embedded in the inner layer of the cuticle. These subcuticular bacteria are spindle‐shaped in Antedon, spiral in Echinocardium, encapsulated rods in Ophiothrix, rods in Ophiura, and a mixture of rods and spirals in both Psammechinus and Astropecten. The discussion considers the possible significance of this widespread, specific and apparently non‐pathologic association between echinoderms and their subcuticular bacteria.
The Vascularization of the Anuran Brain
Authors: Albrecht Ursula , Lametschwandtner Alois , Adam Hans 
Published: April 2010

AbstractThe angioarchitecture of the cerebellum of the toad, Bufo bufo (L.) (Amphibia, Anura) was studied by scanning electron microscopy of vascular corrosion casts. An arterial supply similar to that in the frog by small branches of the superior mesencephalic artery and by terminal branches of central arteries was found. The drainage was demonstrated via mesencephalon (rostro‐dorsal cerebellar regions), rhombencephalon and choroid plexus of the fourth ventricle (auricular areas) as well as via numerous branches of the lateral mesencephalic veins. These vessels leave from different levels of the cerebellum.By comparing corrosion casts with light microscopical sections a correlation between histological structures and vascular patterns was found. The dominating transverse course of the vessels of the Purkinje cell layer was pointed out. Some advantages and limitations of the method used were discussed. To solve the most deplorable disadvantage—the impossibility to receive information about the direction of blood flow—a speculative consideration was presented and opened to discussion.
Biology of the Wild Rabbit, Oryctolagus cuniculus, in Southern Sweden
Authors: Borg Bertil , Andersson Mats , Meurling Patrick 
Published: April 2010

AbstractThe uterine histology of wild rabbits caught in the non‐reproductive season in the Revinge area in southern Sweden was studied (as part of a larger study on the biology of the wild rabbit). The uteri of the yearlings—which do not reproduce—had a low weight and a juvenile histology with a relatively thick, cell‐sparse lamina propria and a weak muscular layer. After the breeding season the uteri of the adults gradually entered a regressed winter state, characterized by a well‐developed muscular layer, a thin, cell‐dense lamina propria and a low mucosal epithelium with few glands. A few yearlings that had ovulated shared this picture. The regressive state gradually disappeared in spring.
VIP‐, Bombesin‐ and Neurotensin‐Like Immunoreactivity in Neurons of the Gut of the Holostean Fish, Lepisosteus platyrhincus
Authors: Holmgren Susanne , Nilsson Stefan 
Published: April 2010

AbstractVIP‐like immunoreactivity was found in nerve fibres in all layers of the gut wall in both stomach and intestine, and was abundant in the myenteric and submucous plexuses. A few fibres were associated with blood vessels. Nerve cells showing VIP‐like immunoreactivity were found in the myenteric plexus. Neurotensin‐like immunoreactivity was found in nerve cells and numerous nerve fibres in the myenteric plexus of both stomach and intestine and in nerve fibres of the circular muscle layer, while bombesin‐like immunoreactivity was confined to a low number of nerve fibres in the myenteric plexus of the stomach. The results indicate that a VIP‐like, a neurotensin‐like and a bombesin‐like peptide are present in neurons of the gut of Lepisosteus.
Relationships Between Cytoplasmic Filaments and Nuclear Envelope in Teleost (Pimelodus maculatus) Endothelial Cells
Authors: Ferri Sylvio 
Published: April 2010

AbstractIn the present report a characteristic pattern showed by cytoplasmic filaments (intermediate‐sized and actin‐like) in the perinuclear area of a freshwater teleost (Pimelodus maculatus) endothelial cells is described for the first time. Thus, many intermediate‐sized filaments are directly inserted in the nuclear envelope, but others are connected to one another and to the nucleus through microfilaments. It is suggested that these particular relationships between the nucleus and cytoplasmic filaments are responsible not only for nuclear anchorage, but also for nuclear movements
Ciliated Receptors in the Pharyngeal Terminal Buds of Larval Lampetra planeri (Bloch) (Cyclostomata)
Authors: Baatrup Erik 
Published: April 2010

AbstractTerminal buds on the gill arches of larval Lampetra planeri have been investigated by scanning and transmission electron microscopy. Each terminal bud is composed of two types of elongated cells, which extend from an apical depression to the basal lamina; one type bears a pair of cilia and the other, microvilli. In addition there are peripheral and basal cells. Nerve‐fibre profiles are lacking within the terminal bud epithelium and contacts between nerves and ciliated cells are established through holes in the basal lamina. The presence of ciliated receptor cells with such a mode of innervation presents a distinct contrast to the morphology of the taste buds of gnathostome vertebrates.
The Presence of Helminths in a Southern Hemisphere Lamprey (Geotria australis Gray), With a Discussion of the Significance of Feeding Mechanisms in Lampreys in Relation to the Acquisition of Parasites
Authors: Lethbridge R.C. , Potter I.C. , Bray R. A. , Hilliard R.W. 
Published: April 2010

AbstractThis paper reports for the first time the presence of helminths in the gut and coelomic cavity of Southern Hemisphere lampreys. Moreover, the records of Pelichnobothrium and Hepatoxylon in the lamprey Geotria australis are also the first records of these helminth genera in any species of lamprey. A consideration of the literature on the parasites and feeding mechanisms of lampreys provides good evidence that those parasites which are found in adult lampreys but typically utilize arthropod intermediate hosts are obtained via the food ingested by the lamprey's host fish.
Ultrastructure of the Spermatozoon of Squilla mantis
Authors: Cotelli Franco , Donin Carla Lora Lamia 
Published: April 2010

AbstractThe specialized spermatozoon of Squilla mantis (Crustacea, Stomatopoda) is round and non‐motile. It is surrounded by an electron‐dense coat, contains a small acrosomal complex, two centrioles consisting of nine doublets and few cellular organelles, while a nucleus sensu stricto is not recognizable. The plasma membrane shows some groove‐like characteristic invaginations. The morphology of this specialized gamete is discussed and compared with that of other Malocostraca.
Terminal Buds in the Branchial Tube of the Brook Lamprey (Lampetra planeri (Bloch))—Putative Respiratory Monitors
Authors: Baatrup Erik 
Published: April 2010

AbstractScanning and transmission electron microscopy showed that the sensory buds are structurally similar to those on the gill arches of the larva. They are composed of ciliated receptors, microvillous supporting cells, peripheral cells and, occasionally, Merkel cells. The connection between receptors and nerves is unusual among vertebrate sensory organs, appearing like a reversed neuromuscular junction. From their structure and localization it is suggested that the terminal buds are chemoreceptive organs involved in evaluation of the respiratory water.
Ultrastructural Studies on Gametogenesis of the Prawn Palaemon serratus (Pennant). I. Oogenesis
Authors: Papathanassiou E. , King P. E. 
Published: April 2010

AbstractThe oogenesis of the common prawn P. serratus is described. The reproductive cycle is annual and there is little evidence for a second spawning period. Oogenesis under the electron microscope follows a typical crustacean pattern and has been divided into seven stages according to the structure of the oocytes. The production of yolk is mainly intra‐oocytic, with a small extra‐oocytic contribution. Yolk, in the form of small granules, arises within the lamellar elements of the rough endoplasmic reticulum. These were then transformed into finely granular yolk bodies. Lipid droplets, as in other crustacean species, arise de novo in the cytoplasm and there is no association between lipids and cell organelles.
Structure and Innervation of Inner Ear Sensory Epithelia in the European Eel (Anguilla anguilla L.)
Authors: Mathiesen Carsten 
Published: April 2010

AbstractHair cell orientations of all inner ear sensory epithelia in glass eel, yellow eel and silver eel are presented. The patterns of hair cell orientation do not change with age. All sensory epithelia increase in area during growth of the eel. Examination of the hair cell population in macula utriculi show constant hair cell densities and increased hair cell population during development. Further, regional differences in hair cell densities and hair cell types are observed. The hair cells/axons ratio increases 3‐fold from glass eel to silver eel stadium. Nerve stainings in silver eel reveal complex innervation patterns with large stubby fibres confined to restricted regions. Histograms of nerve fiber diameters show marked differences from glass eel to silver eel. Growth of sensory epithelia is discussed.
Does the Manatee Have a Pineal Body?
Authors: Ralph Charles L. , Young S. , Gettinger R. , O'Shea T. J. 
Published: April 2010

AbstractThe brain of an adult, female manatee (Trichechus manatus) was prepared for histological examination of the region of the diencephalon and mesencephalon, where the pineal body typically would be located. Careful examination of hematoxylin‐eosin stained, interrupted serial microtomy sections revealed that this animal has a tubular epiphyseal recess apparently lacking organic pineal differentiation. There was no cytological evidence of pinealocytes in the vicinity of the atypical pineal rudiment.
Functions of Scales and Photophores in Mesopelagic Luminescent Sharks
Authors: Reif Wolf‐Ernst 
Published: April 2010

AbstractIn sharks bioluminescence is only known from the family Squalidae. It evolved independently in two out of six squalid subfamilies, Dalatiinae and Etmopterinae. The distribution of photophores was mapped in several species. It is suggested that in the Dalatiinae, which do not school, but migrate vertically, luminescence serves as ventral countershading. The Etmopterinae school and feed close to the bottom. Their luminescence is an aid in schooling. Four different placoid scale patterns are found in luminescent sharks and they allow to accommodation the photophores in the skin.
Distribution and Structure of the Adrenocortical Homolog in Polypterus palmas Ayres
Authors: Youson John H. , Butler David G. 
Published: April 2010

AbstractThe identity, distribution and structure of the adrenocortical homolog (AH) was made in Polypterus palmas Ayres using routine light and electron microscopy and histochemistry for the enzyme δ5‐3β‐hydroxysteroid dehydrogenase (3β‐HSD). The AH is confined to yellow corpuscles which are positioned near the posterior cardinal and renal veins in the anterior two‐thirds of each kidney. The 46–57 spherial to cigar‐shaped corpuscles are placed end to end and are equally distributed in the kidneys. The tortuous cords of epithelial cells of each corpuscle are surrounded by sinusoids and are completely delimited from the haemopoietic and renal tissue of the kidneys. The steroidogenic nature of the cells is demonstrated by their 3β‐HSD activity and their ultrastructure, namely lipid droplets, tubular smooth endoplasmic reticulum and mitochondria with tubulovesicular cristae. Giant mitochondria and gap junctions are notable features of AH cells in this fish. The yellow corpuscles of the kidneys in P. palmas represent the AH and this tissue has a distribution which is in accordance with the taxonomic position of Polypteriformes.
Gap Junction Modification in Hepatic Cells of a Fasting Freshwater Teleost (Pimelodus maculatus)
Authors: Ferri Sylvio 
Published: April 2010

AbstractScarce information concerning gap junction modifications in liver cells is found in the literature. The fine details of gap junctions in the hepatocytes of the teleost Pimelodus maculatus fasting during 3 months are reported for the first time in the present study. In this experimental condition two forms of gap junction appear: a bulge‐like and a ring‐shaped form. The functional significance of these structures is discussed.
Glial Cells in Abdominal Ganglia of Crayfish
Authors: Cuadras Jordi , Martí‐Subirana Anna 
Published: April 2010

AbstractGlial cells of abdominal ganglia of crayfish have been studied by transmission electron microscopy. Four cell types can be defined: (1) perivascular glial cells, close to the vascular spaces; (2) perineuronal glial cells, the processes of which ensheathe neuron perikarya; (3) adaxonal glial cells ensheathing axons; (4) neuropilar glial cells, associated with synapsing terminals in the neuropile.Neuropilar glia, adaxonal glia and the system formed by perineuronal and perivascular glia separate different functional zones of the neurons from the hemolymph or the electron dense extracellular matrix. These glial arrangements could play a similar role in hemato‐neuronal transport. Gap‐like junctions between glia and neuron cell bodies are frequent and could be involved in direct triggering of glial activities related to neurons.
Localization of Carbonic Anhydrase in the Plumula of the Tooth of Lytechinus variegatus (Echinodermata: Echinoidea)
Authors: Chen Chang‐Po , Lawrence John M. 
Published: April 2010

AbstractLabeled inhibitor autoradiography showed that carbonic anhydrase (CA) occurs in (1) the epithelium, (2) free odontoblasts and fibroblasts, (3) row odontoblasts and their membranes surrounding the calcareous parts and (4) extracellular areas. Extracellular CA occurs in areas where fibroblasts and collagen fibers are abundant. The localization of CA suggests that CA facilitates the movement of CO2 through the membrane and/or extracellular spaces to promote calcification.