58 research outputs found

    Atypical location of intracranial germinoma: a case report.

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    Bacterial communities associated with the wood-feeding gastropod <i>Pectinodonta</i> sp. (Patellogastropoda, Mollusca)

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    Even though their occurrence was reported a long time ago, sunken wood ecosystems at the deep-sea floor have only recently received specific attention. Accumulations of wood fragments in the deep sea create niches for a diverse fauna, but the significance of the wood itself as a food source remains to be evaluated. Pectinodonta sp. is a patellogastropod that exclusively occurs on woody substrates, where individuals excavate deep depressions, and is thus a potential candidate for a wood-eating lifestyle. Several approaches were used on Pectinodonta sampled close to Tongoa island (Vanuatu) to investigate its dietary habits. Host carbon is most likely derived from the wood material based on stable isotopes analyses, and high cellulase activity was measured in the digestive mass. Electron microscopy and FISH revealed the occurrence of two distinct and dense bacterial communities, in the digestive gland and on the gill. Gland-associated 16S rRNA gene bacterial phylotypes, confirmed by in situ hybridization, included members of three divisions (Alpha- and Gammaproteobacteria, Bacteroidetes), and were moderately related (90–96% sequence identity) to polymer-degrading and denitrifying bacteria. Gill-associated phylotypes included representatives of the Delta- and Epsilonproteobacteria. The possible involvement of these two bacterial communities in wood utilization by Pectinodonta sp. is discussed

    Guidelines for The management of patients with HIV infection. II. Pregnant women and children.

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    peer reviewedThe management of the HIV infected child is nearly identical to the adult. Nevertheless, there are many clinical, immunological and virological details. Difficulties evoked for the adult have an even bigger importance, in view of the foreseeable longevity of these children under treatment. The reduction of the mother to child transmission, thanks to the AZT-caesarean association, must be continued. The use of anti-retroviral drugs during pregnancy requires a sustained attention because of the potential risks and benefits for the foetus and mother. The long-term impact of these drugs, in children exposed during pregnancy, remains unknown. The follow-up of these children therefore remains important

    Some like it cold: biocatalysis at low temperatures

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    In the last few years, increased attention has been focused on a class of organisms called psychrophiles. These organisms, hosts of permanently cold habitats, often display metabolic fluxes more or less comparable to those exhibited by mesophilic organisms at moderate temperatures. Psychrophiles have evolved by producing, among other peculiarities, "cold-adapted" enzymes which have the properties to cope with the reduction of chemical reaction rates induced by low temperatures. Thermal compensation in these enzymes is reached, in most cases, through a high catalytic efficiency associated, however, with a low thermal stability. Thanks to recent advances provided by X-ray crystallography, structure modelling, protein engineering and biophysical studies, the adaptation strategies are beginning to be understood. The emerging picture suggests that psychrophilic enzymes are characterized by an improved flexibility of the structural components involved in the catalytic cycle, whereas other protein regions, if not implicated in catalysis, may be even more rigid than their mesophilic counterparts. Due to their attractive properties, i.e., a high specific activity and a low thermal stability, these enzymes constitute a tremendous potential for fundamental research and biotechnological applications. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved

    Diet and gut microorganisms of Munidopsis squat lobsters associated with natural woods and mesh-enclosed substrates in the deep South Pacific

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    Squat lobsters of the deep-sea genus Munidopsis are among the most regularly reported crustaceans associated with deep-sea wood falls. They are often thought to indirectly use these substrates for preying or scavenging wood-associated molluscs or annelids, albeit the species M. andamanica has been recently highlighted as a xylophagous specialist. In this work, we examined the feeding appendages, gut contents and gut lining of M. nitida, M. bispinoculata and M. pilosa specimens from natural sunken woods and compared them with specimens of the same species having survived and grown on different hard-to-digest substrates (i.e. woods, turtle shells and whale bones) experimentally submerged in the deep South Pacific. In both cases, all three species directly ingest large wood fragments deeply degraded by microorganisms, but M. nitida also feeds on experimentally submerged whale bone and turtle shell fragments. Munidopsis nitida is also the only species to host a resident gut microflora, but the bacterial morphotypes vary according to the ingested substrate. The results suggest that the three species are most probably opportunistic, bacterivorous detritivores and that M. nitida could be at the beginning of an evolutionary process towards xylophagy within the genus Munidopsis
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