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At least 19 recordsLinked to original sources

PubMedDate not supplied

[Energy metabolism and body mass ratio in bivalves mollusca (Mollusca: Bivalvia)].

On the basis of experimental and published data, the interspecific and intraspecific (ontogenetic) dependence of energy metabolism on body weight in bivalves was calculated. Changes in the parameters of intraspecific allometric dependence under the effect of environmental factors were analyzed. The rate of comparable standard metabolism (coefficient a at k = 0.76) was shown to vary in different taxonomic and zoogeographic groups of bivalves.

Adaptation, Physiological↗

PubMed1997

[Mollusca contagiosa in HIV infection. Clinical manifestation, relation to immune status and prognostic value in 39 patients].

Mollusca contagiosa predominantly affect children; their occurrence in adults is rare. In recent years many descriptions of mollusca contagiosa in immunosuppressed patients, mostly in HIV-infected individuals, have appeared. We analysed the occurrence of mollusca contagiosa in a large group of HIV-patients and examined their relation to the immune status and their prognostic significance. 456 patients with HIV-associated skin disorders were documented in the HIV follow-up clinics at the Department of Dermatology, University Medical Center Benjamin Franklin, Berlin, during the years 1982-1992. Molluscum contagiosum was diagnosed in 39 patients (8.6%). 38 of the 39 patients were homosexual and/or bisexual men. The median age of the patients was 34 years. Large, papular and nodular lesions up to 1 cm in diameter were observed in some, individuals. Frequently, multiple lesions in atypical localizations such as the face were found. Significant immunosuppression was present in the majority of patients with mollusca contagiosa at the time of their first diagnosis; median CD(4+)-T-lymphocyte count was 122/microliter and the median CD4+/CD(8+)-ratio was 0.2. The median survival time was 12 months in patients with mollusca contagiosa. There was no significant difference between the prognosis of patients with mollusca contagiosa and other HIV-infected patients showing similar reduction of their immune status. Our study showed that mollusca contagiosa are a rather frequent infection in HIV-patients. Mainly localized to the face, they are easily diagnosed and may serve as an excellent clinical marker for recognizing advanced immunosuppression in HIV-infection. Survival prognosis of patients with molluscum contagiosum is unfavourable, corresponding to their reduced immune status. The presence of mollusca, however, is not an independent prognostic marker, if the immune status is considered.

AIDS-Related Opportunistic Infections↗

PubMed2006

Identification of several cytoplasmic HSP70 genes from the Mediterranean mussel (Mytilus galloprovincialis) and their long-term evolution in Mollusca and Metazoa.

The HSP70 protein family consists one of the most conserved and important systems for cellular homeostasis under both stress and physiological conditions. The genes of this family are poorly studied in Mollusca, which is the second largest metazoan phylum. To study these genes in Mollusca, we have isolated and identified five HSP70 genes from Mytilus galloprovincialis (Mediterranean mussel) and investigated their short-term evolution within Mollusca and their long-term evolution within Metazoa. Both sequence and phylogenetic analyses suggested that the isolated genes belong to the cytoplasmic (CYT) group of the HSP70 genes. Two of these genes probably represent cognates, whereas the remaining probably represent heat-inducible genes. Phylogenetic analysis including several molluscan CYT HSP70s reveals that the cognate genes in two species have very similar sequences and form intraspecies phylogenetic clades, differently from most metazoan cognate genes studied thus far, implying either recent gene duplications or concerted evolution. The M. galloprovincialis heat-inducible genes show intraspecies phylogenetic clustering, which in combination with the higher amino acid than nucleotide identity suggests that both gene conversion and purifying selection should be responsible for their sequence homogenization. Phylogenetic analysis including several metazoan HSP70s suggests that at least two types of CYT genes were present in the common ancestor of vertebrates and invertebrates, the first giving birth to the heat-inducible genes of invertebrates, whereas the other to both the heat-inducible genes of vertebrates and the cognate genes of all metazoans. These analyses also suggest that inducible and cognate genes seem to undergo divergent evolution.

Animals↗

PubMedDate not supplied

[Mollusca contagiosa in HIV-infected children receiving optimal antiretroviral therapy].

Two children with symptomatic HIV-infection suffered from extended mollusca contagiosa. Intensified antiretroviral therapy including a protease inhibitor, resulted in a decrease of HIV RNA plasma concentration and a dramatic increase of CD4 T cells. Mollusca contagiosa nearly completely disappeared. These cases demonstrated that newly generated CD4 T cells during sufficient antiretroviral treatment have functional abilities. Therefore, sufficient antiretroviral treatment should be offered to HIV infected children with extended mollusca contagiosa before surgical intervention is considered.

AIDS-Related Opportunistic Infections↗

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↗

PubMed2004

The complete sequence and gene organization of the mitochondrial genome of the gadilid scaphopod Siphonondentalium lobatum (Mollusca).

Comparisons of mitochondrial gene sequences and gene arrangements can be informative for reconstructing high-level phylogenetic relationships. We determined the complete sequence of the mitochondrial genome of Siphonodentalium lobatum, (Mollusca, Scaphopoda). With only 13,932 bases, it is the shortest molluscan mitochondrial genome reported so far. The genome contains the usual 13 protein-coding genes, two rRNA and 22 tRNA genes. The ATPase subunit 8 gene is exceptionally short. Several transfer RNAs show truncated TpsiC arms or DHU arms. The gene arrangement of S. lobatum is markedly different from all other known molluscan mitochondrial genomes and shows low similarity even to an unpublished gene order of a dentaliid scaphopod. Phylogenetic analyses of all available complete molluscan mitochondrial genomes based on amino acid sequences of 11 protein-coding genes yield trees with low support for the basal branches. None of the traditionally accepted molluscan taxa and phylogenies are recovered in all analyses, except for the euthyneuran Gastropoda. S. lobatum appears as the sister taxon to two of the three bivalve species. We conclude that the deep molluscan phylogeny is probably beyond the resolution of mitochondrial protein sequences. Moreover, assessing the phylogenetic signal in gene order data requires a much larger taxon sample than is currently available, given the exceptional diversity of this character set in the Mollusca.

Amino Acid Sequence↗

PubMed2001

Trace metals in different species of mollusca, water and sediments from Taiwan coastal area.

Since October 1994, a long-term program of Asia/Pacific Mussel Watch: Taiwan Regional Studies has been carried out. The results indicate that trace metal contents in mollusca varied among 30 different species and the environments (water and sediments) along the Taiwan coast. The orders of bioaccumulation of trace metals in mollusca were: Cu (over 200 microg/g), Thais clavigera > Isognomon legumen > Clibanarius rivescens > Crassostrea gigas; Zn (over 700 microg/g), Moruta granulata > C. gigas > Asiatica cypraea arabica > T. clavigera; Cd (over 5 microg/g), Trochus hanleyanus > Acanthopleura japonica > Nerita albicilla > Patella flexuosa; Pb (over 2 microg/g), P. flexuosa > C. gigas > T. hanleyanus > T. clavigera > C. gigas > Capiyulum mitella; Ni (over 10 microg/g), Meretrix lusoria > Philine sp. > Littoraria scabra > Tridacna squamosa > T. hanleyanus; Cr (over 30 microg/g), Littoraria undulata > T. hanleyanus > N. albicilla > Nerita chamaelor > M. granulata; As (over 20 microg/g), Perna viridis > L. scabra; and Sn (over 5 microg/g), P. viridis > L. undulata> C. mitella> C. gigas. Their seasonal and regional variations as well as their correlation are evaluated and discussed.

Animals↗

PubMed2003

A monovalent anion affected multi-functional cellulase EGX from the mollusca, Ampullaria crossean.

A cellulose hydrolytic enzyme was isolated from the stomach juice of Ampullaria crossean, a kind of herbivorous mollusca. The enzyme was purified 45.3-fold to homogenety by ammonium sulfate precipitation, DEAE-Sephadex A-50 column, Bio-gel P-100 gel filtration column, and phenyl-Sepharose CL-4B column chromatography. The enzyme was designated as cellulase EGX. The purified enzyme is a multi-functional enzyme with the activities of exo-beta-1,4-glucanase (14.84 U/mg for p-nitrophenyl beta-D-cellobioside), endo-beta-1,4-glucanase (40.3 U/mg for carboxymethyl cellulose), and endo-beta-1,4-xylanase (196 U/mg for soluble xylan from birchwood). The monovalent anions such as F(-), Cl(-), Br(-), I(-), and NO(3)(-) are essential for its exo-beta-1,4-glucanase activity but have no effect on the activity for xylan, while I(-) higher than 5mM would inhibit the exo-beta-1,4-glucanase activity. The monovalent anions Cl(-) and Br(-) activate its endo-beta-1,4-glucanase activity. Binding of Cl(-) enhances the thermostability of EGX, but does not affect its fluorescence emission spectrum. The molecular mass of EGX is 41.5 kDa, as determined by SDS-PAGE. The pI value is about pH 7.35. The xylan hydrolytic activity of EGX reaches to the maximum between pH 4.8 and 6.0 and the pNPC hydrolytic activity reaches the maximum between pH 4.8 and 5.6, while that for CMC hydrolytic activity is between pH 4.4 and 4.8. Preliminary results showed that the enzyme was secreted by the mollusca itself.

Ammonium Sulfate↗

PubMed1998

Characterization of a low-sulfated chondroitin sulfate from the body of Viviparus ater (mollusca gastropoda). Modification of its structure by lead pollution.

A chondroitin sulfate was purified from the body of Viviparus ater(Mollusca gastropoda) and analyzed for molecular mass, constituent disaccharides, and structure by 1H NMR and 1H 2D NMR. A quite unique glycosaminoglycan species was isolated having a high molecular mass (greater than 45,000) and low charge density, about 0.60, due to the presence of 42% non-sulfated disaccharide, 5% 6-sulfated disaccharide, 48% 4-sulfated disaccharide, and 5% 4,6-disulfated disaccharide. Specimens of Mollusca were also submitted to lead exposure for different times, and the effect on chondroitin sulfate structure was studied. After 96 h treatment a strong decrease in chondroitin sulfate content was observed with a significant modification of its structure producing a more desulfated polymer, in particular in position 4 of the galactosamine unit. Simultaneously, the amount of unsaturated non-sulfated disaccharide increased with an overall decrease of the charge density.

Animals↗

PubMedDate not supplied

Ciliary ultrastructure of polyplacophorans (Mollusca, Amphineura, Polyplacophora).

This study is part of a series of papers aiming to investigate the phylogenetic significance of ciliary ultrastructure among molluscs and to test the hypothesis of a relationship between Xenoturbella and the molluscs. The ultrastructure of the ciliary apparatus on the gills of the polyplacophorans Leptochiton asellus and Tonicella rubra was studied. The gill cilia of the two species are similar in shape. The free part of the cilium is long with a slender distal part. There are two ciliary rootlets. One of them is short, broad and placed on the anterior face of the basal body. The other rootlet is conical and has a vertical orientation. Among the mollusca, two ciliary rootlets in the ciliary apparatus of multiciliate ectodermal cells have only been reported from the Chaetodermomorpha and Neomeniomorpha. This character state is likely plesiomorphic for the Mollusca and indicates a basal (nonderived) position of these taxa among the molluscs. No possible synapomorphic character with Xenoturbella bocki was found.

Animals↗

PubMed1995

From Polyplacophora to Cephalopoda: comparative analysis of nitric oxide signalling in mollusca.

The distribution of putative nitric oxide synthase (NOS)-containing cells has been analysed using NADPH-d histochemistry in the CNS and peripheral tissues in more than 2D ecologically and systematically different molluscan genera representing 3 main classes of the phylum MOLLUSCA: Polyplacophora (Lepidopleurus, Lepidozona, Katharina), Gastropoda (Littorina, Lymnaea, Aplexa, Physa, Planorbarius, Planorbis, Helisoma, Biomphalaria, Helix, Limax, Cepaea, Bulla, Aplysia, Phyllaplysia, Philine, Pleurobranchea, Tritonia, Armina, Flabellina, Cadlina) and Cephalopoda (Octopus, Sepia, Rossia, Loligo). Several species were used for more detailed immunohistochemical, biochemical, biophysical and physiological studies to further assay of NOS activity and to analyse functional roles of nitric oxide (NO) in these animals. The main conclusions of our comparative analysis and literature survey can be summarised as following: (i) There is strong evidence for the presence of NO-dependent signalling pathways in different molluscan species. (ii) We hypothesise that a general tendency in the evolution of NADPH-d-reactive cells in Mollusca is a migration of nitrergic function from periphery to the CNS. Also, different isoforms of NOS appear to be present in any one species. (iii) One of the main functional targets of NO signalling is the feeding system. However, there are obvious differences between predators (many labelled central motoneurons) and herbivorous species (many labelled peripheral putative sensory cells) as well as between land/freshwater and marine animals. Nevertheless, in all species tested NO-activated feeding-like motor patterns in the buccal ganglia. Additional functional and cellular targets for NO in molluscs are also considered. We briefly review neuromodulatory mechanisms of NO action and we consider molluscs as useful model systems for investigations of the roles of NO.

Animals↗

PubMed2006

All the three ParaHox genes are present in Nuttallochiton mirandus (Mollusca: polyplacophora): evolutionary considerations.

The ParaHox gene cluster contains three homeobox genes, Gsx, Xlox and Cdx and has been demonstrated to be an evolutionary sister of the Hox gene cluster. Among deuterostomes the three genes are found in the majority of taxa, whereas among protostomes they have so far been isolated only in the phylum Sipuncula. We report the partial sequences of all three ParaHox genes in the polyplacophoran Nuttallochiton mirandus, the first species of the phylum Mollusca where all ParaHox genes have been isolated. This finding has phylogenetic implications for the phylum Mollusca and for its relationships with the other lophotrochozoan taxa.

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↗

PubMed2005

Analysis and characterization of the transcriptional unit of a new Mytilus galloprovincialis (Mollusca: Bivalvia) hsp70 gene.

We isolated, analysed and characterized the transcriptional unit of an hsp70 gene of Mytilus galloprovincialis (Mollusca: Bivalvia). Sequence analysis of a total of 3653 bp, revealed a 1914 bp ORF encoding for a 637-amino acid polypeptide that exhibits all the characteristic signatures of the cytoplasmic members of the HSP70 family. The ORF is not interrupted by introns and its 5'-flanking region contains five putative heat shock elements (HSEs), both indicating for an inducible hsp70 gene. Furthermore, nucleotide and amino acid sequence alignments with HSP70 genes from several molluscan and non-molluscan species confirmed that the newly isolated gene, the first complete in the genus Mytilus and in the Mollusca phylum, is a cytoplasmic and inducible hsp70 gene.

Amino Acid Sequence↗

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↗

PubMedDate not supplied

Microstructure of Monoplacophora (Mollusca) shell examined by low-voltage field emission scanning electron and atomic force microscopy.

The shell of Micropilina arntzi (Mollusca: Monoplacophora), a primitive molluscan class, was examined by using field emission scanning electron microscopy (FESEM) at low voltage and atomic force microscopy (AFM). The use of these two techniques allowed the observation of fine details of Micropilina arntzi shell and contributed to bring new features concerning the study of molluscan shell microtexture. Imaging with low-voltage FESEM provided well-defined edge contours of shell structures, while analyzing the sample with AFM gave information about the step height of stacked internal structures as well as the dimension of the particles present in their surface at a nanometric level. The shell microstructure of Monoplacophora species presents different patterns and may be a taxonomic implication in the systematic studies of the group.

Animals↗

PubMed2004

Repetitive DNAs in the slug Milax nigricans: association of ribosomal (18S-28S and 5S rDNA) and (TTAGGG)n telomeric sequences in the slug M. nigricans (Mollusca: Gastropoda: Pulmonata).

Spermatocyte chromosomes of the slug Milax nigricans (Mollusca: Gastropoda: Pulmonata) were studied using silver staining (Ag-NOR) and fluorescent in situ hybridization (FISH) with four repetitive DNA probes [18S rDNA, 5S rDNA, (TTAGGG)n and (GATA)n]. Silver impregnation was inadequate to localize the chromosome sites of nucleolus organizer regions (NORs) since no silver dots occurred on the chromosomes at spermatogonial metaphase and a diffuse silver stainability could be observed on the bivalents at metaphase-I. Unlike silver staining, single-colour rDNA FISH consistently mapped major ribosomal sites (18S-28S rDNA) on two small-sized chromosomes in spermatogonial cells and on the correspondent metaphase-I bivalent in spermatocytes. While telomeric (TTAGGG)n sequence hybridized to all chromosomes, (GATA)n probe localized abundant hybridization sites, dispersed throughout the genome. Simultaneous double-colour FISH demonstrated a close chromosomal association of 18S-28S rDNA, 5S rDNA and (TTAGGG)n.

Animals↗

PubMed2004

Phylogenetic relationships among Opisthobranchia (Mollusca: Gastropoda) based on mitochondrial cox 1, trnV, and rrnL genes.

We reconstructed the phylogenetic relationships among 37 species representing seven main lineages within Opisthobranchia (Mollusca: Gastropoda) based on a mitochondrial fragment that included partial cox 1, complete trnV, and partial rrnL genes (about 2500 bp). Phylogenetic analyses confirmed tentatively that all studied main opisthobranch lineages conformed monophyletic groups except Nudibranchia. The sacoglossan Ascobulla was placed as the most basal lineage of opisthobranchs. The basommatophoran pulmonate Siphonaria was recovered within Opisthobranchia between Ascobulla and the remaining opisthobranchs. The latter were divided into two different lineages that await formal description: on one side, Cephalaspidea, Tylodinoidea, and Anaspidea (sharing features in the reproductive, digestive, and circulatory systems) were grouped together and, on the other Architectibranchia and Nudipleura (sharing similarities in the circulatory system) were recovered as sister group taxa. Two well-supported clades were recovered within Nudipleura: Pleuroanthobranchia (new taxon) and Cladobranchia. Pleuroanthobranchia (Pleurobranchoidea plus Anthobranchia) was defined by the presence of blood gland, the presence of calcareous spicules in the integument and the presence of a caecum with an opening directly into the stomach. The new molecular phylogeny provided a robust framework for comparative studies, and prompted a revision of the morphological synapomorphies diagnosing the main clades within opisthobranchs.

Amino Acid Sequence↗