bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural Observations on the Dwarf Male of Bonellia viridis (Echiura)
Authors: Schuchert P. , Rieger R. M. 
Published: April 2010

AbstractThe organization of the dwarf male of Bonellia viridis was studied by electron microscopy. The epidermis is formed by two types of epithelial cells: the majority are multiciliated cells; highly vacuolated, non‐ciliated cells are less abundant. The body wall musculature consists of an outer circular, a diagonal, and a longitudinal layer. As a unique feature in coelomate spiralians it was found that the perikarya of all muscle cells are located internal to the entire contractile muscular layer. The muscles are solitary myocytes embedded in extracellular matrix. Masses of secretory and indifferent cells occur inside the muscles. Two types of secretory cells were distinguished. Both of them apparently undergo holocrine secretion. A complete lining of thin peritoneal cells delimits the body cavity. Also, the gut and sperm sac have a complete peritoneal lining. The coelomic lining of the gut is a single‐layered myoepithelium, that of the sperm sac a pseudo‐stratified myoepithelium. The vas deferens was seen to be ciliated. The entrance of the sperm sac is formed by a ciliated funnel that leads into the reservoir by means of a thin, ciliated canal. The existence of repeated transverse nerves and of four longitudinal nerve cords is described for the first time.
The Anatomy of the Circulatory System in the Arminid Nudibranch Armina maculata Rafinesque, 1814 (Gastropoda: Opisthobranchia)
Authors: García Francisco José , García‐Gómez José Carlos 
Published: April 2010

AbstractIn Armina maculata the heart lies anteriorly and has a large muscular ventricle and a delicate auricle running obliquely to the antero‐posterior axis. The auriculoventricular valve and the aortic valve are disposed at the anterior end of the auricle and ventricle respectively. The aortic trunk is located just anterior to the ventricle and gives off several arteries, which extend through the whole body. The main arteries are: the cephalic artery (to the buccal apparatus); the posterior artery (to the notum, digestive glands, ovotestis and renal chamber); the pedal artery (to the foot); and the genital arteries (supplying the different organs of the reproductive system). These data are compared with those of other arminacean species.
On the Microanatomy of the Supraoesophageal Ganglion of Some Amphinomids (Polychaeta Errantia), with Further Discussion of the Innervation and Homologues of the Polychaete Palps
Authors: Orrhage Lars 
Published: April 2010

AbstractEarlier papers dealing with the anatomy of the amphinomid brain were studied. Discrepancies in the studied works prompted a re‐investigation of the central nervous system of these animals. In this paper the brain commissures, the clusters of ganglion cells and the innervation of the antennae, the palps and the nuchal organs of Eurythoe complanata, Amphinome rostrata, Pherecardia striata, and Notopygos variabilis are described in some detail. The brain of Hermodice carunculata is studied more cursorily. The results, summarized in schematic diagrams, are compared with corresponding observations of the brains of ‘spiomorphic’ and ‘serpulimorphic’ polychaetes and to information given by earlier authors about structures in the Nereidiformia and Aphroditiformia. Using the major Remanian criteria for identifying homologies, equivalents in the amphinomid brain and the central nervous systems of some ‘sedentary’ and ‘errant’ families are proposed. As a consequence, some earlier opinions about the morphological value of the cephalic appendages of the amphinomids are strengthened while others are rejected. The necessity of further investigations of the polycheaete nervous system is emphasized.
Histochemical and Ultrastructural Features of the Biceps Brachii of the African Chameleon (Chamaeleo senegalensis)
Authors: Abu‐Ghalyun Younis 
Published: April 2010

Abstract Characteristics of reptilian muscle fibres were investigated in the biceps brachii of the African chameleon, Chamaeleo senegalensis. Fibres were classified as slow and fast. These types of fibre were distinguished on the basis of histochemical staining for myofibrillar ATPase (mATPase). Fast fibres stained dark for mATPase while slow fibres stained light.The patterns of innervation of slow and fast fibres were investigated by staining nerve endings for acetylcholinesterase activity. Slow fibres have a pattern of multiple innervation, whereas fast fibres are associated with individual endplates. The organization of the myofibrils and the sarcoplasmic reticulum in slow muscle fibres from the chameleon biceps brachii was compared with that in fast fibres. Slow fibres lacked an M‐line and the Z‐lines were uneven. They had fibrils that were not clearly separated from each other and the sarcoplasmic reticulum was poorly developed. These features are in sharp contrast to those of fast fibres which had straight Z‐lines, clear M‐lines and well‐developed sarcoplasmic reticulum.
Ultrastructural Study of the Filum Terminate and Caudal Ampulla of the Spinal Cord of Amphioxus (Branchiostoma lanceolatum Pallas)
Authors: Ruiz Maria Soledad , Anadon Ramón 
Published: April 2010

AbstractThe filum terminale and caudal ampulla of amphioxus were studied by electron microscopy. The filum terminale consists of ependymal cells whose cilia are directed caudally. Remarkably, nerve fibres course through the filum terminale and caudal ampulla and end on the basal lamina forming neuro‐connective structures. Moreover, these nerve boutons are divisible into several classes according to their vesicle content. Boutons containing large dense‐cored vesicles are very similar in appearance to the neurosecretory terminals found in the caudal spinal cord of some vertebrates. These observations on nerve fibres suggest that a primitive neurosecretory system similar to the fish urophysis is present in the amphioxus.
Changes in the Saccus Vasculosus Epithelium During the Smoltification Process in Atlantic Salmon (Salmo salar)
Authors: Sanson Kirsti , Kryvi Harald 
Published: April 2010

AbstractThe changes that take place in the saccus vasculosus epithelium during smoltification of Atlantic salmon (Salmo salar) are described. The major cell type of the epithelium, the coronet cells, have a number (mean = 32) of spherical protrusions connected with a non‐motile cilium to the apical part of the cell. The protrusions extend into the saccus lumen. In parr the protrusions become more spherical during the spring season, while in smolt the opposite process takes place. Parr coronet cells have most of the mitochondria in the apical part of the cell, while in smolt they are concentrated basally. The relative areal fraction of heterochromatin in the nuclei increase from 23 to 29 during the smoltification process. The results are consistent with the view that the coronet cells take an active part in the smoltification process.
Burrowing, Locomotion and Other Movements of the Echiuran Ochetostoma caudex
Authors: Biseswar R. 
Published: April 2010

AbstractBurrowing, iocomotory and other movements of the echiuran Ochetostoma caudex have been examined and discussed. A continuous body cavity enables the worm to undergo peristaltic waves to pump water through the burrow without causing locomotion. The animal is capable of both forward and backward locomotion in its burrow. During forward locomotion, retrograde peristaltic waves are utilized which advance the animal in a step‐wise fashion. Pressure changes within the coelom during burrowing, locomotion and during irrigation movements have been measured with the use of electronic recording techniques and the results interpreted in relation to direct visual observation. The structural and functional specializations for burrowing are discussed and compared with the activities of Priapulus caudatus, Sipunculus nudus and Bonellia viridis.
The Central and Peripheral Nervous System of Acoela (Plathelminthes). An Electron Microscopical Study
Authors: Bedini Celina , Lanfranchi Alberto 
Published: April 2010

AbstractThe fine structure of the nerve cells and the neuropile in the brain of acoels and the peripheral nervous system and the synapses have been studied. On the basis of the vesicle content, four nerve cell types are distinguished. The presumptive glial cell is also visualized. The synapses appear to be of the following four types: asymmetrical, ribbon, symmetrical and electrical. The peripheral nervous system consists of a subepithelial and a submuscular plexus; they present asymmetrical and symmetrical synapses. In the light of these results, the nervous system of acoels should no longer be considered as primitive.
Ciliated Epidermal Cells in Non‐teleost Actinopterygian Fish
Authors: Webb Jacqueline F. , Northcutt R. Glenn 
Published: April 2010

AbstractScanning electron microscopy reveals the presence of ciliated epidermal cells that form halos around canal pores and pit lines of the mechanoreceptive lateral line system in two actinopterygian fish, Polypterus and Acipenser. Transmission electron microscopy shows that the cilia exhibit a typical 9 + 2 microtubule configuration and are not directionally polarized. The function, developmental origin and systematic significance of ciliated epidermal cells in actinopterygian fish are considered.
Development of the Testis During Post‐metamorphic Life in the Southern Hemisphere Lamprey Geotria australis Gray
Authors: Potter I. C. , Robinson E. S. 
Published: April 2010

AbstractSpermatogenesis during post‐metamorphic life in the anadromous parasitic lamprey Geotria australis was examined in histological sections of testes of animals collected in the field or maintained in the laboratory. The fully metamorphosed downstream migrants of G. australis possessed a very small testis in which the germ cells consisted of irregularly arranged prospermatogonia. By the end of the subsequent protracted marine trophic phase, the testis had increased in cross‐sectional area by about 20 times and become organised into well‐defined cysts. Since approximately 40% of these cysts possessed spermatocytes and 12% contained spermatids or early sperm, meiosis is initiated prior to the non‐feeding upstream migration, which in G. australis lasts for the unusually long period of 15–16 months. The incidence of cysts with meiotic and post‐meiotic stages decreased during the first 3 months of the spawning run before starting to rise during subsequent months. Spermiogenesis was never completed in any animals caught in the field during the first 9 months of the upstream migration or in those subsequently held in the laboratory up to and beyond November, the month when spawning naturally takes place. The phasing and asynchrony of spermatogenesis during post‐metamorphic life in G. australis differs markedly from the situation in Northern Hemisphere lampreys.
Ciliated Sensory Cells in the Rostral Organ of the Coelacanth Latimeria chalumnae (Smith 1939)
Authors: Jørgensen J. Mørup 
Published: April 2010

AbstractThe rostral organ of the coelacanth Latimeria chalumnae contains a sensory epithelium with luminated ciliated sensory cells, which very much resemble electroreceptors from other non‐teleost fish. This, as well as the innervation and a dorsal nucleus, indicate that this interesting species is electroreceptive.
Sensory Structures in Tadpole Larvae of the Ascidians Microcosmus exasperatus Heller and Herdmania momus (Savigny)
Authors: Svane Ib , Young Craig M. 
Published: April 2010

AbstractIn this paper we describe the larval morphology of two species from the ascidian family Pyuridae, Microcosmus exasperatus and Herdmania momus, with special emphasis on components of the cerebral vesicle. Larvae have not previously been described for any species in the large genus Microcosmus. Besides a difference in size (larvae of H. momus are about 40% larger than those of M. exasperatus), larvae of the two species differ primarily in the number and arrangement of sensory structures. Both species possess a well‐developed statocyte but only H. momus has an ocellus. The absence of an ocellus in M. exasperatus is unique among pyurid ascidians. An auxiliary vesicle was found situated on the left side of the cerebral vesicle in both species. However, unlike the larvae of H. momus and other pyurid species, there is no apparent communication between the auxiliary and cerebral vesicles of M. exasperatus. Epithelial cells in the auxiliary vesicles of both species carry modified cilia about 2 μm in diameter; auxiliary vesicles of H. momus also have simple cilia with axonemes in a 9 + 0 microtubule configuration. In H. momus the membranes of the epithelial cells are highly convoluted and extend into the lumen of the auxiliary vesicle. Morphological arrangements of auxiliary vesicles and globular cilia reported so far in ascidian tadpoles are contrasted and discussed.
Ultrastructure of the Flame Bulbs and Protonephridial Capillaries of Microstomum sp. (Platyhelminthes, Macrostomida)
Authors: Rohde K. , Watson N. 
Published: April 2010

AbstractThe terminal part of the protonephridia of Microstomum is formed by a branching proximal canal cell and (at least?) two terminal cells. Each weir consists of longitudinal (sometimes convoluted) ribs continuous with the cytoplasm of the terminal cell. Internal leptotriches arise from the terminal and proximal canal cells. Near the tip of the flame, the proximal canal cell tube is surrounded by the more external terminal cell and connected to it by a septate junction. Large cristate mitochondria are densely packed in the terminal and canal cells. The flame bulb of Microstomum differs markedly from that of other macrostomids (Macrostomum, Paramalostomum) examined. Phylogenetic implications are discussed.
Ultrastructure of the Penicillate Podia of the Spatangoid Echinoid Echinocardium cordatum (Echinodermata) with Special Emphasis on the Epidermal Sensory‐Secretory Complexes
Authors: Flammang Patrick , De Ridder Chantal , Jangoux Michel 
Published: April 2010

AbstractThe spatangoid echinoid Echinocardium cordatum possesses specialized penicillate podia that handle sediment particles during burrowing and feeding. Epidermal complexes, which occur on podial surfaces directly contacting the sediment, each comprise four cells: a non‐ciliated secretory cell containing granules rich in mucopolysaccharides (NCS cell), a ciliated secretory cell containing granules of unknown composition (CS cell), and two ciliated non‐secretory cells (CNS cells). The cilium of the CS cell is subcuticular whereas that of each CNS cell traverses the cuticle. We propose that these four cells constitute a sensory‐secretory complex wherein the ciliated cells are sensory cells and the secretory cells function for adhesion and de‐adhesion. More exactly, an NCS cell adhesive and a CS cell de‐adhesive would be sequential and would be initiated by two successive stimulations transduced by cilia when the podium touches the sediment. Cilia that first contact the sediment are those protruding through the cuticle from the CNS cells. Their stimulation would result in the secretion of an adhesive material by the NCS cells. Subsequently, the subcuticular cilia of CS cells would be stimulated when the podial digitations closely squeeze the substrate, and this would induce the secretion of a de‐adhesive. These two antagonistic secretions would allow the podium to pick up and discharge sediment repetitively during burrowing and feeding.
Peroxidase Localization of Lectin Binding Sites on Plasma Membrane of the Surface Epidermis in the Rusty Blenny, Blennius sanguinolentus (Pallas, 1811)
Authors: Fasulo Salvatore , Licata Aurelio , Contini Antonia , Ainis Luigi , Mauceri Angela , Zaccone Giacomo 
Published: April 2010

Abstract Various horseradish peroxidase‐conjugated lectins have been used for the ultrastructural localization of carbohydrate moieties of glycoconjugates on plasma membranes of the surface cells of Blennius sanguinolentus epidermis.Concanavalia ensiformis (Con A), Arachis hypogaea (PNA), Pisum sativum (PSA) and Ulex europaeus (UEA I) lectins bind only to the outermost plasma membranes, the glycocalyx and the intercellular spaces of the surface cells. Other lectins applied, such as Triticum vulgare (WGA), Glycine max (SBA) and Griffonia simplicifolia (GS I), presenting GlcNAc and GaINAc specificity, reacted with the plasma membranes of basolateral domains and gave an attenuated reaction with the outermost plasma membranes. The results suggest that regional differences exist in the distribution patterns of GlcNAc and GalNAc‐terminating glycoconjugates. The possible implication of the polarized expression of these glycoconjugates in ion transport is discussed.
Ultrastructure of Spermiogenesis in Hyla japonica (Anura, Amphibia)
Authors: Lee Young Hwan , Kwon Ae Sook 
Published: April 2010

AbstractSpermiogenesis in Hyla japonica was examined using transmission electron microscopy. Features which have not been reported previously during spermiogenesis of anurans include: (1) the neck of pericentriolar material is well developed, (2) the perforatorium contains many microtubules, (3) the tail is composed of axoneme and axial rod, but has no undulating membrane. Such a structure has not been described in amphibians, although it occurs in fish and mammals, and (4) the modified microtubules have one to two long projections. So far they have not been observed in any species except Gerris and Aphyosemion. With the exception of the above characteristics, the spermatozoa of Hyla japonica are remarkably similar to those of Bufo sp.
Structure and Development of the Notochord ‘Elastica Externa’ and Nearby Components of the Elastic Fibre System of Agnathans
Authors: Schinko I. , Potter I. C. , Welsch U. , Debbage P. 
Published: April 2010

AbstractBetween 15 days and 3 months in age, the ‘elastica externa’ of the notochord sheath of larval lampreys develops from patches of moderately dense and amorphous material into a thick, continuous and electron‐dense layer. In both lampreys and hagfish, this layer stains strongly with Verhoeff's elastic stain and aldehyde fuchsin and is penetrated by collagen fibrils on both its outer and inner boundaries. Peroxidase labelling using an antibody raised against human elastin specifically labels both the notochord ‘elastica externa’ and the elastic fibre system of lampreys. The diameters of the microfibrils (10–13 nm) of the oxytalan, elaunin and elastic fibres of lampreys and hagfish are the same as those of higher vertebrates. The connective tissue immediately dorsal and ventral to the notochord of lampreys contains mainly oxytalan fibres in very young ammocoetes, a combination of oxytalan, elaunin and elastic fibres in older ammocoetes, and predominantly elastic fibres in adult lampreys. While the region of the endomeninx at the base of the spinal cord contains almost exclusively oxytalan fibres in young ammocoetes, it also possesses numerous elastic fibres in adult lampreys. These findings indicate that, as in higher vertebrates, the elastic fibres of lampreys develop from oxytalan fibres via elaunin fibres.
Sperm Axoneme in Some Apterygote Insects Examined by Computer‐aided Image Analysis
Authors: Dallai R. , Bellon P. L. , Lanzavecchia S. , Afzelius B. A. 
Published: April 2010

AbstractSperm tail axonemes from three insect species, representing the three apterygote orders Diplura, Archeognatha and Zygentoma, have been examined by high resolution electron microscopy. The samples were fixed in a mixture of glutaraldehyde and tannic acid followed by uranyl acetate post‐fixation and the electron micrographs were subjected to computer analysis in order better to characterize the minute details of the axonemal microtubules. The dipluran Campodea was seen to have a row of accessory microtubules composed of 13 protofilaments, the archeognath Machilinus to have two rows of accessory microtubules composed of 16 protofilaments. and the zygentoman Lepismodes to have accessory microtubules in contact with the flagellar doublets and with a wall containing 16 protofilaments and an electron‐dense lumen. The axonemal structure in Zygentoma is the one most similar to those of the pterygote insects. The protofilaments of the axonemal doublets were seen to have a somewhat widened interspace between some pairs of protofilaments and these ‘gaps’ coincided with the location of the basal parts of the outer dynein arm, the inner dynein arm, the spoke, and the intertubular material. It hence seems that these microtubule‐associated structures influence the architecture of the microtubular wall.
Skin and Blood Vessels of the Snout of the Australian Lungfish, Neoceratodus forsteri, and their Significance for Interpreting the Cosmine of Devonian Lungfishes
Authors: Bemis W. E. , Northcutt R. Glenn 
Published: April 2010

AbstractImproved structural and functional interpretations regarding the dermal skeleton of Paleozoic lungfishes (Dipnoi) can be derived from a direct comparison of Recent and fossil tissues. In particular, skin from the snout of adult Australian lungfish (Neoceratodus forsteri) contains horizontal plexuses and vertical capillary loops which resemble in structure, size and density components of the cosmine layer in such Paleozoic lungfishes as Dipterus valenciennesi and Chirodipterus australis. In addition to these dermal papillae, the skin of the snout also contains ampullary electroreceptors, goblet cells, compound mucus glands, and terminal branches and openings of the mechanoreceptive lateral line system. Pore canal systems of fossil lungfishes previously have been interpreted as housing electroreceptors or other cutaneous sense organs of the lateral line system. In contrast, we regard pore canal systems as evidence of a complex cutaneous vasculature involved in the deposition of mineralized tissues. Prevailing ideas on the structure and biological role of cosmine are reinterpreted, including the theory that electroreceptors played an important part in the origin of the dermal skeleton.
Localization of a SALMFamide Neuropeptide in the Larval Nervous System of the Sand Dollar Dendraster excentricus
Authors: Thorndyke Michael C. , Crawford Bryan D. , Burke Robert D. 
Published: April 2010

AbstractUsing immunocytochemical methods we describe the localization of serotonin and the SALMFamide peptide, S1 (GFNSALMFamide), during embryonic and larval development of the echinoid Dendraster excentricus. Anti‐SI immunoreactivity first appears in the apical ganglion in late gastrulae at the same time as anti‐serotonin immunoreactivity. Initially, anti‐S1 immunoreactivity is restricted to fibres of the neuropile, but in later feeding stages, cell bodies are also immunoreactive. Anti‐S1 immunoreactivity appears as 2–4 cells in the oral ganglion of early prism stage larvae, whereas anti‐serotonin immunoreactivity does not occur in the oral ganglion until the 8‐arm stage. Anti‐S1 immunoreactivity also occurs in diffuse fibres in the oesophagus and in a single fibre encircling the pyloric sphincter of the gut. A reticular network associated with the apical surface of the epithelial cells of the vestibule of the adult rudiment was anti‐S1 immunoreactive. In double‐labelling experiments, anti‐serotonin and anti‐S1 immunoreactivity co‐localize in the neuropile of the apical ganglion. The distribution of S1, in association with putative sensory cells in the apical and oral ganglia and with muscles of the oesophagus and gut, suggests S1 may have diverse functions in the larval nervous system. The distribution of anti‐S1 immunoreactivity in echinoid embryos and larvae supports the proposal that SALMFamide‐like peptides are widely shared in echinoderms and potentially have a fundamental role in neural function.