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At least 19 recordsLinked to original sources
PubMed1987

On the status of the study of invertebrate neurons in tissue culture--phyla Mollusca and Annelida.

The utilization of tissue culture in neurobiological studies is discussed for all phyla phylogenetically preceding Phylum Arthropoda. Only two phyla, Mollusca and Annelida, are represented in such studies. The members of Phylum Mollusca which have been so investigated are Aplysia, Helisoma and Lymnaea. The mollusc Aplysia has been used to investigate several processes, including neurosecretion, synaptic transmission and synaptogenesis. Helisoma was employed to study factors regulating neurite growth and the specificity of synapse formation; mechanisms of neurite growth were investigated in the snail Lymnaea. The only member of Phylum Annelida involved in appropriate studies has been the leech Hirudo. This organism was used to investigate axonal regeneration and synaptic mechanisms.

Animals↗
PubMed1990

Plasma concentrations of lidocaine and prilocaine and analgesic effect after dermal application of EMLA cream 5% for surgical removal of mollusca in children.

The plasma concentrations of lidocaine and prilocaine after dermal application of EMLA cream 5% were determined in two clinical studies. The cream (10-16 g) was applied to a total surface area of 100-160 cm2. Each area was covered by a Tegaderm dressing (3M) in order to obtain occlusion. An application time of 2 hours was used. Two age groups of ten children were studied: 2-3 years and 6-8 years. In both groups venous blood samples were drawn prior to application and at 2, 3, 4 and 5 hours. In addition, in one of the studies, the cream was used during the surgical removal of mollusca in order to study the analgesic effect of the cream. The absorption of the local anaesthetics as indicated by plasma concentrations was far below toxic levels. The highest individual concentration of lidocaine was 315 ng/ml and of prilocaine 215 ng/ml. The analgesic effect was sufficient--eight out of ten patients experienced no or slight pain. Transient local reactions (paleness, redness) were frequently observed. In one patient with eczema present at the application site prior to the application, a reaction persisted for one week. Dermal analgesia provided by EMLA is a safe and effective method for alleviation of pain from removal of mollusca and the plasma concentrations are innocuous.

Analgesia↗
PubMed1986

Systemic treatment of mollusca contagiosa with inosiplex.

The ensuing regression of mollusca contagiosa in 7 of 9 children, 6 of whom were suffering from atopic dermatitis, was observed during systemic treatment with inosiplex. In our report the involutional process of mollusca contagiosa did not differ clinically from the inflammatory course observed in spontaneous healing. It is supposed that inosiplex enhances underlying defective immunological mechanisms which lead to a restoration of the host defence.

Adolescent↗
PubMed1992

Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and between individual S. velum organisms suggested that one species of symbiont is dominant within and specific for this host species. Phylogenetic analysis of the 16S sequences of the symbionts indicates that they lie within the chemoautotrophic cluster of the gamma subdivision of the eubacterial group Proteobacteria.

Animals↗
PubMedDate not supplied

[Microbiological control of edible Mollusca in Milan's trade in 1971-1974].

A microbiological control of edible Mollusca in trade of Milan Market and coming from Adriatic's cultivation basins during 1971-1974 was performed. During 1971-1973 anterior to choleric epidemy of 1973, alot of 2680 mussel's specimens were examined with the ACIS 1949 method, of which 60% (1611) favorable and 39.9% (1069) contrary; a single semple presented a S. paratyphi B germ. During 1974 with a new regulamentation 111 mussel's specimens were examined with M.S. 1973 more restrictive method (Colonbacterial titre). With that method 41 samples were not favorable which were favorable with ACIS method. A new hygienic angayement results therefore necessary.

Commerce↗
PubMed1991

Identification of muramyl derivatives in Mollusca Gastropoda tissue.

Previous findings have demonstrated the presence of muramic acid and the lack of sialic acid in gastropod glycoconjugates from different tissues. The present study investigated the composition of muramyl derivatives in Mollusca Gastropoda tissue from the foot, mantle and periesophageal ganglia, using HRP-labeled lectins (LTA, UEA I, GSA IB4, GSA II, DBA, SBA, RCA II, WGA, PNA, ConA) and glycosidase digestion (neuraminidase, lysozyme, alpha-L-fucosidase, beta-N-acetylglucosaminidase, alpha-N-acetylgalactosaminidase). Muramyl derivatives from the tissue examined showed some differences related to the composition of the terminal disaccharides. Indeed, foot and mantle mucocytes exhibited muramic acid in a terminal position, linked to (subterminal) N-acetylgalactosamine, whereas in neuron cells muramic acid was present in an internal position and linked to N-acetylglucosamine. Diversities also occurred between foot and mantle mucocytes with respect to the receptor sugar for penultimate N-acetylgalactosamine.

Animals↗
PubMed1991

Extracellular giant rickettsiae associated with bacteria in the gill of Crassostrea gigas (Mollusca, Bivalvia).

Extracellular giant rickettsiae closely associated with bacteria with a Gram-negative type wall are reported among the basal insertions of the cilia of the gill epithelium of the oyster Crassostrea gigas (Mollusca, Bivalvia) from the north of Spain. These rickettsiae are extremely pleomorphic cells with a maximum 9 microns length. The internal elements are ribosome-like particles and DNA strands are distributed in some light areas. Some rickettsial cells show one to two vacuole-like dense inclusions formed by curved concentric bands approximately 4 nm thick separated by an approximately 5-nm light space (myelin-like bodies). Numerous bacteria are closely associated with the rickettsiae in the surrounding zone. The cytopathic effects of this association seemed to give rise to the epithelial lysis and concomitant disappearance of the apical microvilli and cilia and the consequent destruction and disintegration of the gill epithelial cells, where these rickettsiae live in close proximity. This is believed to be the first description of extracellular giant pathogenic rickettsiae of these oyster species.

Animals↗
PubMed1971

Opal precipitation by marine gastropods (Mollusca).

The high silicon content of certain radular sites of the Patellacea (Mollusca, Gastropoda) is shown by infrared absorption spectrums to be fixed in the form of the mineral opal. Opal and goethite mineralize the cusps and bases of the teeth. The presence of opalized base plates only in the families Acmaeidae and Lepetidae appears to be of taxonomic significance. Minimum values of the volume of fixation and of the turnover rate of opal by the Patellacea are calculated to assess the role of this previously neglected taxon in biological fixation of silica in the oceans. The significance of these organisms points to the much needed study of the silica transport system in tissue-grade Metazoa.

Animals↗
PubMedDate not supplied

Astronotus ocellatus (Cichlidae:Pisces) and Macropodus opercularis (Anabatidae:Pisces) as predators of immature Aedes fluviatilis (Diptera:Culicidae) and Biomphalaria glabrata (Mollusca:Planorbidae).

Two fish species, Astronotus ocellatus (Cichlidae) and Macropodus opercularis (Anabatidae) were tested for predacious behavior toward immature mosquitoes (Aedes fluviatilis, Diptera:Culicidae) and schistosomiasis snail hosts (Biomphalaria glabrata, Mollusca:Planorbidae), in the presence or absence of non-living food and in laboratory conditions. A. ocellatus, a species indigenous to Brazil, was a very efficient predator of both organisms (alpha = 0.05); M. opercularis, an exotic species, preyed well on immature mosquitoes, but small snails and snail egg-masses were ingested only irregularly. Both fish species seemed to prefer live to non-living food.

Aedes↗
PubMed1992

Cell interactions influence the pattern of biomineralization in the Ilyanassa obsoleta (Mollusca) embryo.

Ilyanassa obsoleta larvae have two calcium carbonate-containing organs, shell and statocyst, which are derived from five micromere cells (2a, 2c, 2d, 3c, 3d). "Internal shell," an abnormal, internal calcium carbonate mass, was previously observed when cells which normally induce shell and statocyst were removed. This study utilizes multiple-cell deletions to examine how these calcium carbonate-producing precursors control the pattern of biomineralization, whether it is in external shell, statocyst, or internal shell. It was demonstrated that internal shell was solely derived from any of these five cells. However, there was a quantitative difference in the frequency of internal shell production depending upon which cells, as well as how many, are deleted. In general, when external shell or statocyst production was diminished, as the result of removing several of the calcium carbonate-producing cells, internal shell was deposited instead. The presence of internal shell can best be explained as the result of altered interactions between these five cells after one or more have been deleted. Electron diffraction and transmission electron microscopy show that internal shell differs from normal shell in both structure and crystal morphology and it can also be produced by statocyst precursors. Thus, both the deletion and electron microscopy data support the interpretation that the development of internal shell is controlled by shell- and statocyst-producing cells when the cell communication between these cells is disrupted.

Animals↗
PubMed1977

Chemotactic behavior of the sperm of chitons (Mollusca: Polyplacophora).

Observations of sperm behavior in the vicinity of gradients of egg-water or alcohol extracts of whole freshly-spawned eggs of several chitons reveal what appear to be directed movements of sperm up the gradient, resulting in the aggregation of motile sperm at the gradient source. Plots of the tracks of the sperm approaching the gradient source show that the cells increase the time during which they move toward the source and decrease the time spent moving away. Although this resembles the kinesis behavior shown by bacteria in a gradient, the path directions are markedly non-random. The reorientation behavior of thigmotactic sperm involves enlargement of the normal circular path diameter in the direction of the source and an alternation of tight loops and wide circular arcs, with the latter made in the direction of the source. The form of the path of attracted chiton sperm is like that observed during chemotaxis of the sperm of the hydroid Tubularia and the tunicate Ciona and resembles the behavior of Ciona sperm in that there is no increase in velocity as the cells move up the gradient. However, unlike the cnidarian and urochordate cases, the attracting substances extracted from chiton eggs do not act species-specifically.

Animals↗
PubMed1990

Ultrastructure of the sperm and spermatogenesis in five South African species of the trochid genus Oxystele (Mollusca, Prosobranchia).

Sperm of Oxystele are of the primitive type, which is typical of molluscs using external fertilization. They comprise a head, which is composed of a barrel-shaped nucleus and large conical acrosome; a midpiece of five or six spherical mitochondria; and a tail, with a 9 + 2 arrangement of microtubules. The morphology of the sperm broadly resembles that of the sperm of other trochids as well as that of the sperm of the Pleurotomariidae, Haliotidae, and Fissurellidae but differs considerably from that of the Patellidae. Each of the five species examined was found to have a different sperm morphology. Our results support the suggestion of Heller and Dempster (in preparation) that Oxystele variegata Anton actually consists of two sympatric species. The morphological changes that occur during spermatogenesis are very similar in all species and resemble descriptions given for other molluscs with primitive sperm.

Animals↗
PubMed1989

Ultrastructural and cytochemical study of spermatogenesis in Scrobicularia plana (Mollusca, Bivalvia).

The ultrastructure of the mature spermatozoa and spermatogenesis of the bivalve Scrobicularia plana are described. Support cells extend from the basal lamina to the lumen of the testis and are laterally connected to the germinal epithelium. Germ cells present intercellular bridges and flagella since the spermatogonial stage. While spermatogonia and spermatocytes appear connected to support cells by desmosome-like junctions, elongated spermatids are held at the acrosomal region by support cell finger-like processes. During spermiogenesis, the acrosomal vesicle differentiates from a golgian saccule and then migrates to the nuclear apex. A microtubular manchette arising from centrioles surrounds the acrosomal vesicle, the nucleus, and the mitochondria at the time these three organelles start their elongation, disappearing after that. The mature spermatozoon of S. plana lacks a distinct midpiece because the mitochondria extend from the region of the pericentriolar complex along the nucleus anteriorly for approximately 1.4 microns. The features of this bivalve type of modified spermatozoon are compared with those of other animal groups having similar modifications.

Acid Phosphatase↗
PubMed1978

Unusual aggregations of tubules associated with endoplasmic reticulum in digestive cells of Alderia modesta (Mollusca: Gastropoda: Sacoglossa).

Aggregations of cylindriform tubules closely packed in a hexagonal arrangement and associated with the rough-surfaced endoplasmic reticulum (RER) are described in cells of the digestive gland of a sacoglossan gastropod. Each tubule is approximately 61 nm in outer diameter and the central lumen is lined with a layer of finely granular material. The tubule wall is composed of approximately 22 dense subunits. Adjacent tubules are associated with a pair of indistinct granules. Membranes of the RER frequently join the aggregations. The lumen of a tubule may be continuous either with the intracisternal space of the RER or with the cytoplasmic matrix of the cell. It is suggested that the aggregations of tubules are elaborations of the endoplasmic reticulum.

Animals↗
PubMed1975

Location of glycogen in spermatids and spermatozoa of the shipworm, Bankia australis (Teredinidae, Bivalvia, Mollusca).

The periodic acid-thiocarbohydrazide-silver proteinate technique and alpha-amylase digestion were used to locate glycogen in the spermatids and sperms of the bivalve Bankia australis. Glycogen was found in the middle piece and around the acrosome in spermatozoa, apparently randomly scattered throughout the cytoplasm of young spermatids, and in a cytoplasmic bead in old spermatids.

Acrosome↗