. Growth is observed from pH 5 to pH 8, the optimum being at pH 6. The salinity range for growth is 10-50 g NaCl l N1 , the optimum being at 30 g l N1 . The isolate is able to grow on a broad spectrum of carbohydrates or complex proteinaceous substrates, and growth is stimulated by L-cystine and elemental sulfur. The GMC content of the genomic DNA is 29O1 mol %. According to phylogenetic analysis of the 16S rDNA gene, the strain is placed within the order Thermotogales, in the bacterial domain. On the basis of 16S rDNA sequence comparisons and morphological, physiological and genotypic characteristics, it is proposed that the isolate be described as a novel species of the genus Marinitoga, with Marinitoga piezophila sp. nov. as the type species. The type strain is KA3 T (l DSM 14283 T l JCM 11233 T ).

The whole-cell protein inventory of the deep-sea barophilic hyperthermophile Thermococcus barophilus was examined by one-dimensional SDS gradient gel electrophoresis when grown under different pressure conditions at 85 degrees C (Topt). One protein (P60) with a molecular mass of approximately 60 kDa was prominent at low pressures (0.3 MPa hydrostatic pressure and 0.1 MPa atmospheric pressure) but not at deep-sea pressures (10, 30, and 40 MPa). About 17 amino acids were sequenced from the N-terminal end of the protein. Sequence homology analysis in the GenBank database showed that P60 most closely resembled heat-shock proteins in some sulfur-metabolizing Archaea. A high degree of amino acid identity (81%-93%) to thermosome subunits in Thermococcales strains was found. Another protein (P35) with molecular mass of approximately 35.5 kDa was induced at 40 MPa hydrostatic pressure but not under low-pressure conditions. No amino acid sequence homology was found for this protein when the 40 amino acids from the N-terminal end were compared with homologous regions of proteins from databases. A PTk diagram was generated for T. barophilus. The results suggest that Phabitat is about 35 MPa, which corresponds to the in situ pressure where the strain was obtained.

Aims: To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate. Methods and Results: The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus. Conclusions: The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas. Significance and Impact of the Study: For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species.

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Skaftárkatlar are two subglacial lakes located beneath the Vatnajökull ice cap in Iceland associated with geothermal and volcanic activity. Previous studies of these lakes with ribosomal gene (16S rDNA) tag sequencing revealed a limited diversity of bacteria adapted to cold, dark, and nutrient-poor waters. In this study, we present analyses of metagenomes from the lake which give new insights into its microbial ecology. Analyses of the 16S rDNA genes in the metagenomes confirmed the existence of a low-diversity core microbial assemblage in the lake and insights into the potential metabolisms of the dominant members. Seven taxonomic genera, Sulfuricurvum, Sulfurospirillum, Acetobacterium, Pelobacter/Geobacter, Saccharibacteria, Caldisericum, and an unclassified member of Prolixibacteraceae, comprised more than 98% of the rDNA reads in the library. Functional characterisation of the lake metagenomes revealed complete metabolic pathways for sulphur cycling, nitrogen metabolism, carbon fixation via the reverse Krebs cycle, and acetogenesis. These results show that chemolithoautotrophy constitutes the main metabolism in this subglacial ecosystem. This assemblage and its metabolisms are not reflected in enrichment cultures, demonstrating the importance of in situ investigations of this environment.