bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Ultrastructural Account of Otoplanid Turbellaria Neuroanatomy I. The cerebral ganglion and the peripheral nerve net
Authors: Ferrero Enrico Antonio , Lanfranchi Alberto , Bedini Celina 
Published: April 2010

AbstractThe otoplanid nervous system investigated in Otoplana truncaspina Lanfranchi, 1969 and Parotoplanella heterorhabditica Lanfranchi, 1969 consits of: (a) an ellipsoidal cerebral ganglion located between the gut and the cephalic intestine and invested by a fibrillar collagen‐like capsule 0.3 μm thick; (b) anterior extracapsular ganglion cell clusters; (c) a peripheral nerve plexus locally thickened at the level of the epithelial sensory and glandular areas, with extensive synaptic connections. At least two neuron types can be identified within the ganglion: (a) an inner layer close to the central neuropile of the 1st type of neurons, showing a vesicular cytoplasm rich in RER and Golgi complexes processing both round, clear, 25–45 nm in diameter, and dense cored vesicles, 50–80 nm in diameter; (b) an outer layer of the 2nd type of neurons, adjoining the capsule and filled with uniformly dense vesicles, 60–90 nm in diameter. Synaptic endings in the neuropile are provided with clear vesicles and dense cored vesicles or uniformly dense vesicles. The presynaptic side has paramembranous projections channelling the vesicles to the active zone; omega‐like profiles are also observed. Thin banded muscle fibres run within the brain. A comparison is drawn with the other turbellarian neuron types described in the literature, to suggest their possible function. The functional implications of the synaptic ultrastructure are discussed.
First Evidence of an Altitudinal Variation in the Brain Size of Triturus alpestris alpestris (Laur.) (Amphibia, Caudata, Salamandridae)
Authors: Breuil M. , Thireau Michel 
Published: April 2010

AbstractThis study deals with geographical variations in brain‐body weight relationships in the alpine newt, Triturus alpestris alpestris. According to the canonical axis, C.A., the mean allometry in this species is 0.473±0.03; an allometry value of 0.5 is considered to be characteristic of Caudata. No significant difference was observed between the four reduced major axes (R.M.A.) of lowland animal samples (mean value of the pooled samples, C.A. = 0.469±0.210). In contrast, between the mountain samples a significant difference exists, the R.M.A. in the sample from l'Alpe d'Huez (Isère, France) being 0.331±0.57 as compared to 0.72±0.18 in the sample from Durmitor (Montenegro, Yugoslavia). In spite of this difference, their encephalisation index (Ie) did not differ significantly, having on average a value of 118.18±8.5, against Īe = 93.8±8.0 for lowland samples. A significant difference in encephalisation index between mountain and lowland alpine newts thus exists. This is probably the first observation in vertebrates of an encephalisation index increase with altitude. A biological hypothesis is proposed to explain this peculiar observation.
The Dentition and Feeding Mechanism in Adults of the Southern Hemisphere Lamprey Geotria australis Gray
Authors: Hilliard R. W. , Potter I. C. , Macey D. J. 
Published: April 2010

AbstractScanning electron micrographs of the teeth and sections and dissections of the head have been used to describe the functional interrelationships between the dentition and associated cartilages, muscles and ligaments in adults of the southern hemisphere lamprey Geotria australis. These studies, together with manipulation of the piston and oral disc in living specimens, elucidated the probable feeding mechanism in this species. The main cutting action appears to result from a scissoring movement brought about by the rapid interlocking of the three sharp and stout cusps of the transverse lingual lamina with large grooves on the rear face of the supraoral lamina. The movement of excised flesh back through the oral passage to the pharynx would be facilitated by the action of the pair of strongly cuspid longitudinal lingual laminae. The unique oral disc teeth of G. australis are apparently adapted to allow the disc to slide forward over the host and yet restrict any tendency to slip backwards.
Effect of Cytochalasin B on Eggs of Atlantic Salmon and Rainbow Trout
Authors: Bolla Sylvie , Refstie Terje 
Published: April 2010

AbstractCytochalasin B action has been investigated in polyploidisation and gynogenesis in Atlantic salmon and rainbow trout. Solutions of 10, 20, 30 and 50 mg/1 were used to treat eggs from 35 h° to the 2‐, 4‐ and 8‐cell stages for rainbow trout, from 35 h° to the 2‐ and 4‐cell stages, and 50 h° to the 8‐cell stage for salmon. Survival rate was low in all treated groups. Low frequencies of polyploid and gynogenetic individuals were observed in embryos and alevins by means of two methods: DNA analysis by flow cytometry and chromosome counting. All polyploids observed were triploids without evidence of mosaicism. A few spontaneous diploid gynogenetic rainbow trout were registrated, as well as spontaneous triploid salmon, in controls.
Distribution of Nerve Elements Showing FMRFamide‐like Immunoreactivity in Hydromedusae
Authors: Mackie G. O. , Singla C. L. , Stell W. K. 
Published: April 2010

AbstractImmunofluorescence tests with antisera to various peptides reveal the presence of a FMRFamide‐like peptide in neurons of hydromedusae belonging to three orders. An avian pancreatic polypeptide‐like peptide may also be present in certain neurons. Distribution of FMRFamide‐like immunoreactivity (Fa‐IR) has been studied in Proboscidactyla (O. Limnomedusae), Phialidium and Aequorea (O. Leptomedusae) and Aglantha (O. Trachymedusae). These findings are compared with results obtained with Polyorchis (O. Anthomedusae) by Grimmelikhuijzen and Spencer [J. comp. Neurol. 230, 361 (1984)]. All species show Fa‐IR neurons in the tentacles linked by interconnecting neurites running in the outer marginal nerve ring. A Fa‐IR plexus is present in the manubrium and, except in Aglantha, this system merges with a plexus associated with the subumbrellar radial muscles. As in Polyorchis, the swimming motor neurons are unstained. In contrast to this species, only a small percentage of the neurites composing the nerve rings are stained. The giant axons of Aglantha show no Fa‐IR. The cnidothylaces of Proboscidactyla contain neurons reacting with antisera to FMRFamide and APP. Present evidence suggests that in hydromedusae Fa‐IR is confined to distinct subsets of neurons. These appear to be either sensory units or units supplying smooth muscles, but they are not involved in the innervation of striated muscles.
Aspects on the Ultrastructure of the Cephalic Region in Two Species of Acrobelinae (Nematoda, Cephalobidae)
Authors: Boström Sven 
Published: April 2010

AbstractThe lip structures termed labial probolae, characteristic for the subfamily Acrobelinae, and the anterior sense organs have been studied by electron microscopy. The labial probolae consist of an amorphous tissue with denser strengthenings. They do not contain any sensory structures or musculature. The anterior sense organs consists of: (1) six inner labial sensilla, each with one receptor ending in a pore on a papilla; (2) six outer labial sensilla, each with one receptor ending in the cuticle; (3) four cephalic sensilla, each with two receptors, one ending in a pore on a papilla and the other in the cuticle; (4) two amphids, each with 12 sensory neurons basally; (5) accessory sensilla ventro‐laterally. The combination of several chemoreceptive anterior sensilla and the morphological diversity of the labial probolae within the subfamily may aid in the utilization of different soil microhabitats.
The Question of a Dermohyal in Brachiopterygian Fishes
Authors: Bjerring Hans C. 
Published: April 2010

AbstractSince the turn of this century it has been suggested between whiles that brachiopterygians (i.e. the species of Polypterus and Calamoichthys) are actinopterygians. One of the arguments used recently by advocates of this widespread contention is the dermohyal, an exoskeletal branchial‐arch element which they assert occurs in both groups. However, this argument has to be rejected: the dermohyal does not exist in brachiopterygian fishes. The writer proposes to maintain the view that brachiopterygians are not actinopterygians until better arguments to the contrary are forthcoming.
Functional Morphology of the Olfactory Organs in the Spiny Dogfish (Squalus acanthias L.) and the Small‐spotted Catshark (Scyliorhinus canicula (L.))
Authors: Theisen Birgit , Zeiske Eckart , Breucker Haide 
Published: April 2010

AbstractThe morphology of the olfactory organs in two sharks, the spiny dogfish and the small‐spotted catshark, was studied by light microscopy and electron microscopy (TEM and SEM). The olfactory epithelium is arranged on olfactory lamellae which are provided with secondary folds. The epithelium mainly consists of microvillous receptor cells, multiciliated supporting cells and basal cells. The find of only one type of receptor cells, the microvillous type, is discussed and the condition considered a derived (apomorphic) character. The route of the water current through the olfactory organ and the different driving forces of the ventilation process are subject to discussion. In both the pelagic dogfish and the bottom‐dwelling catshark the pressure difference between the incurrent and excurrent nostrils achieved by active swimming appears to be the driving force, whereas the role of the beating of the non‐sensory cilia is not evident. In the bottom‐dwelling catshark the ventilation of the olfactory organ is also supported by the respiratory activity.
Ultrastructural Observations on Fertilization in Dionchus remorae (Platyhelminthes, Monogenea, Dionchidae)
Authors: Justine Jean‐Lou , Matter Xavier 
Published: April 2010

AbstractUltrastructural observations are presented for some of the stages occurring during fertilization in Dionchus remorae (a gill parasite of Echeneis naucrates) and are believed to be the first published concerning a monogenean. Fertilized female germ cells were found in the ovary. Several loops of the spermatozoon were present within the oocyte cytoplasm; the sperm nucleus became electron lucent and the parallel peripheral doublets of the axonemes became increasingly divergent. The cortical granules in the oocyte were not released immediately after penetration by the spermatozoon. The homogeneity apparently found in the oocyte ultrastructure and process of fertilization in the monogeneans and digeneans contrasts with the variety that exists in their sperm ultrastructure.
The Fine Structure of the Integument of Free‐Living and Parasitic Copepods. A Review
Authors: Bresciani J. 
Published: April 2010

AbstractA perusal of the literature on copepod cuticles has been made, and results of the investigation of six species made by the author are included in this review.The integument of copepods is of the arthropod type. Pore canals and other structures traversing the cuticle, common in most arthropods, are not always present in free‐living and some parasitic copepods.In parasitic forms, with advanced morphological changes, the cuticle is generally very thin and the epicuticle in many species forms external microvilli‐like structures. In the copepods hitherto investigated the epicuticle is probably the sole layer present in the cuticle.Some copepods show specialized regions of the cuticular surface, the function of which still remains obscure. Integumental organs and integumental structures are numerous and variable. The association of bacteria with the cuticle has been observed in many species.The structure of the integument of parasitic species lacking an alimentary tube and in close contact with the host tissue or hemocoelic cavity supports the idea that the integument could be the obligatory site of nutrient uptake. In spite of the relatively few species of copepods that have been investigated, a remarkable variation of cuticular fine structure has been revealed.
Fine Structure of Heart, Pericardium and Glomerular Vessel in Cephalodiscus gracilis M'Intosh, 1882 (Pterobranchia, Hemichordata)
Authors: Dilly Peter Noel , Welsch Ulrich , Rehkämper Gerd 
Published: April 2010

AbstractHeart, pericardium and glomerular vessel of Cephalodiscus gracilis have been studied with the electron microscope. The lumen of the heart is lined by a basal lamina and an associated epithelium, composed of myoepithelial cells with well developed thin and thick myofilaments. The heart is located in the pericardial cavity, which is deliminated by the pericardium. The latter is composed of two flat layers of myoepithelia with fused basal laminae. The outer layer of the pericardium is the protocoelomic lining, and the inner layer is the ‘parietal’ pericardial epithelium. The myoepithelium forming the heart wall can be considered to represent the ‘visceral’ pericardial epithelium. The spacious glomerular vessel is lined by a basal lamina, on which typical podocytes rest. These cells indicate that ultrafiltration takes place through the wall of the glomerular vessel. The lumen of the vessel contains fine granular material (presumably precipitated blood proteins), fibrils with a faint cross striation, suggesting that they represent collagen, and stellate cells, which in part line the vessel. Since ultrafiltration requires hydrostatic pressure, it is inferred that the blood flow is from the dorsal region then through the heart and into the glomerular vessel.
Fine Structure of Tentacles, Arms and Associated Coelomic Structures of Cephalodiscus gracilis (Pterobranchia, Hemichordata)
Authors: Dilly Peter Noel , Welsch Ulrich , Rehkämper Gerd 
Published: April 2010

AbstractThe tentacles of the pterobranch Cephalodiscus, a hemisessile ciliary feeder, originate from the lateral aspects of the arms and are covered by an innervated epithelium, the majority of its cells bearing microvilli. Each side of a tentacle has two rows of ciliated cells and additional glandular cells. The coelomic spaces in the tentacles are lined by cross‐striated myoepithelial cells, allowing rapid movements of the tentacles. One, possibly two, blood vessels accompany the coelomic canal. On their outer sides the arms are covered by a simple ciliated epithelium with intra‐epithelial nerve fibres; the inner side is covered by vacuolar cells. On both sides different types of exocrine cells occur. The collar canals of the mesocoel are of complicated structure. Ventrally their epithelium is pseudostratified and ciliated; dorsally it is lower and forms a fold with specialized cross‐striated myoepithelial cells of the coelomic lining.Arms, tentacles, associated coelomic spaces and the collar canal of the mesocoel are considered to be functionally interrelated. It is assumed that rapid regulation of the pore width is possible and even necessary when the tentacular apparatus is retracted, which presumably leads to an increase of hydrostatic pressure in the coelom.
Hormonal Control of Seasonal Growth in a Temperate Zone Toad Bufo bufo
Authors: Wind‐Larsen Hanne , Jørgensen C. Barker 
Published: April 2010

AbstractYoung toads were exposed to a light regimen of 12L/12D at 21°C and fed meal‐worms before hibernation in the autumn, when the toads reduce feeding and discontinue growth, and after hibernation in the spring, when feeding and growth is resumed. In the autumn treatment of the toads with bovine growth hormone maintained feeding and growth; in the spring the treatment protracted the period of feeding and growth. Thyroxin had no obvious effects on growth. It is concluded that the annual growth pattern of temperate zone toads is controlled by an internal rhythm in the secretion of growth hormone.
The Cardiogastric Gland and Alimentary Tract of Caenolestid Marsupials
Authors: Richardson K. C. , Bowden T. A. J. , Myers P. 
Published: April 2010

AbstractThe stomach of the South American marsupial family Caenolestidae has a gland on its lesser curvature around the cardia. This cardiogastric gland is bi‐lobed, typically 11times5 mm and bears a distinctive, highly folded mucosa which forms sac‐like invaginations. These open into the stomach lumen via 40–60 slit‐like orifices. The gland mucosa contains unbranched gastric glands which are considerably longer than those of other gastric glands present elsewhere in the stomach. The cells within the cardiogastric gland show intense eosinophilic staining properties, with the parietal cells being larger than those found in other regions of the stomach, as well as being arranged in clusters. Argentaffin cells are not present in the stomach mucosa. The gross morphology of the stomach and intestine is similar to that found in small carnivorous marsupials.
Immunohistochemical Identification of the Adenohypophysial Cells in the Indian Paddy Field Frog, Rana limnocharis
Authors: Kar Satyabrata , Naik Dhruba Raj 
Published: April 2010

AbstractCells of the pituitary pars distalis (PD) and pars intermedia (PI) in the frog Rana limnocharis have been identified by an unlabelled antibody enzyme method using antisera developed in rabbit against mammalian hypophysial hormones. On the basis of their immunoreactivity, six types of cells, viz. thyrotropic (TSH), gonadotropic (GTH), prolactin (PRL), growth hormone (GH), corticotropic (ACTH) and melanotropic (MSH), cells have been recognized. GTH and PRL cells are distributed throughout the PD. GH cells usually occur in the anterodorsal and central region of the gland. Immunoreactive TSH cells are fewer in number and are localized in the ventromedian region of the PD. Cells showing immunoreactivity to ACTH 1–24 antiserum are encountered in the rostroventral part of the PD. Cells of the PI also show immunoreactivity to ACTH 1–24 antiserum. PI cells cross‐react with α‐MSH antiserum at all dilutions up to 1: 50 000. However, when the same antiserum was used at dilutions up to 1: 20 000, the ACTH cells of the PD also showed cross‐reactivity.
Immunocytochemical Demonstration of Serotonin and Neuropeptides in the Nervous System of Gyrodactylus salaris (Monogenea)
Authors: Reuter Maria 
Published: April 2010

AbstractA whole mount immunocytochemical (ICC) method has been used for the investigation of immunoreactivity (IR) to the molluscan cardioactive peptide FMRF‐amide, to 9 vertebrate neuropeptides—leu‐enkephalin, growth hormone‐releasing factor (GRF), urotensin I, urotensin II, bovine pancreatic peptide (BPP), β‐endorphin, substance P, secretin and insulin—and to the bioamine 5‐HT in the nervous system (NS) of the trematode Gyrodactylus salaris belonging to the taxon Monogenea. Positive results were obtained using antisera to FMRF‐amide, leu‐enkephalin, urotensin I, GRF and to 5‐HT. The present results are the first documentation of the presence of neuroregulatory peptides and a bioamine in the nervous system (NS) of Monogenea. Differences in the distribution pattern of the IR to the different antisera indicate that different subsets of neurons are revealed. In addition, details of the basic neuroanatomical pattern in monogeneans are confirmed by the whole mount ICC method used in this study. Negative results were obtained with antisera to urotensin II, substance P, β‐endorphin, secretin, insulin and bovine pancreatic polypeptide (BPP).
Coelomic Cells in the Connective Tissue Spaces of the Clitellar Epithelium of Lumbricus friendi Cognetti, 1904 (Oligochaeta): an Ultrastructural Study
Authors: de Quiros Isabel F. Bernaldo , Benito Jesus 
Published: April 2010

AbstractThe ultrastructure of the connective tissue spaces in the clitellar epithelium has been studied in the earthworm Lumbricus friendi. Four morphological types of coelomic cells are described: amoebocytes, mucocyte‐like cells, pigment cells and crystal‐containing cells. The amoebocytes are characterized by the presence of spherical to oval electron‐dense granules, phagocytic vacuoles and numerous microtubules located in the Golgi areas. The mucocyte‐like cells show the features of the mucocytes reported in enchytraeid worms (globular inclusions with filamentous and homogeneous, moderately electron‐dense material, as well as a filopodous process). The pigment cells contain typical spindle‐shaped osmiophilic granules, microtubules (not reported before) and glycogen particles. The crystal‐containing cells show inclusions which are polygonal in section with a striated substructure (periodicity of about 4.5 nm). Apart from the mucocyte‐like cells, the coelomocytes showed cytoplasmic processes attached to the basement membrane of the spaces. The possible functions of these cells are discussed and a common peritoneal origin is postulated on the base of their morphological and cytological features.
The Nervous System of the Male Dinophilus gyrociliatus (Annelida: Polychaeta). I. Number, Types and Distribution Pattern of Sensory Cells
Authors: Windoffer Reinhard , Westheide Wilfried 
Published: April 2010

AbstractThe entire nervous system of the smallest annelid hitherto known, the dwarf male of the highly dimorphic species Dinophilus gyrociliatus, has been reconstructed by means of TEM investigations of serial ultrathin sections. Altogether there are 68 neurons, 40 of which have a sensory function. The structure and distribution of them is described. The receptor endings of the 20 sensory cells of each side are located either in two groups — the anterior receptor group and the posterior receptor group — or are singly positioned in the integument. Structural differences of the apical portion of the dendrites enables four types of receptors to be distinguished: three types with emergent cilia and one type with non‐emergent cilia. Neurons with emergent cilia can be monociliated collar cells as well as mono‐ or multiciliated cells without collar. Special vesicle‐in‐vesicle structures, are located close to the basal portion of the cilia in some of these cells. The non‐emergent cilia border closely to a neighbouring epidermal cell and contain a prominent intraciliary vesicle. The function of receptors is discussed with regard to a comparison with receptors in other polychaete species, structural specializations and their distribution pattern on the animal's surface.
Settlement and Metamorphosis of Rhabdopleura normani (Hemichordata: Pterobranchia)
Authors: Lester Susan M. 
Published: April 2010

AbstractSettling and metamorphosing larvae of the pterobranch hemichordate Rhabdopleura normani from Bermuda were examined with light microscopy, providing the first detailed description of the morphological changes during larval metamorphosis in pterobranchs. The swimming larvae settle within 24 h after being released from the parent tube. The settled larva immediately everts the ventral depression and surrounds itself with a translucent, sealed cocoon. During metamorphosis, which takes place over 7–10 days within the protective cocoon, structural changes occur in the following sequence: (1) differentiation of the oral shield from the anterior region; (2) budding of the two arms from the mid‐dorsal surface; (3) development of the posterior stalk from the adhesive organ; (4) budding of the tentacles on the arms; (5) formation of the pharynx from invaginated ectoderm; (6) formation of the gut and pericardium from the remaining mesenchyme. The gut is the last structure to become functional. The larva relies on stored nutrients throughout metamorphosis. The metamorphosed juvenile builds a tube at an opening in the cocoon and begins to feed. Similarities with lecithotrophic bryozoan and enteropneust larvae are discussed.