Oleispira antarctica gen. nov., sp. nov., a novel hydrocarbonoclastic marine bacterium isolated from Antarctic coastal sea water The taxonomic characteristics of two bacterial strains, RB-8 T and RB-9, isolated from hydrocarbondegrading enrichment cultures obtained from Antarctic coastal marine environments (Rod Bay, Ross Sea), were determined. These bacteria were psychrophilic, aerobic and Gram-negative with polar flagella. Growth was not observed in the absence of NaCl, occurred only at concentrations of Na + above 20 mM and was optimal at an NaCl concentration of 3-5 % (w/v). The major cellular fatty acids were monounsaturated straight-chain fatty acids. The strains were able to synthesize the polyunsaturated fatty acid eicosapentaenoic acid (20 : 5v3) at low temperatures. The DNA G+C contents were 41-42 mol%. The strains formed a distinct phyletic line within the c-Proteobacteria, with less than 89?6 % sequence identity to their closest relatives within the Bacteria with validly published names. Both isolates exhibited a restricted substrate profile, with a preference for aliphatic hydrocarbons, that is typical of marine hydrocarbonoclastic micro-organisms such as Alcanivorax, Marinobacter and Oleiphilus. On the basis of ecophysiological properties, G+C content, 16S rRNA gene sequences and fatty acid composition, a novel genus and species within the c-Proteobacteria are proposed, Oleispira antarctica gen. nov., sp. nov.; strain RB-8 T (=DSM 14852 T =LMG 21398 T ) is the type strain. INTRODUCTIONHydrocarbon-degrading micro-organisms usually exist in very low abundance in the absence of oil pollution. A pollution event is rapidly followed by a bloom of these micro-organisms, the populations of which expand to nearly complete dominance of the viable microbial community during the period of contamination (Margesin & Schinner, 1999;Harayama et al., 1999). The properties of hydrocarbon compounds depend on the ambient temperature. Short-chain alkanes become less volatile and more water-soluble at low temperatures, whereas longer-chain compounds precipitate under cold conditions as waxes, respectively rendering them bioavailable and inaccessible to microbes. Such behaviour at low temperatures obviously reflects the establishment of specific oil-based marine microbial communities at these temperatures that are somehow different from those observed in a temperate climate. The most important permanently cold habitat is the ocean, since the temperature of more than 90 % of the seawater volume is below 5 uC. Genera that are typically well represented in cold, petroleum-contaminated sites are Acinetobacter, Arthrobacter, Mycobacterium, Pseudomonas, Rhodococcus and Sphingomonas, many of which can grow solely on hydrocarbon compounds and have been previously characterized as petroleum degraders of terrestrial origin (Rosenberg et al., 1992;MacCormack & Fraile, 1997). Although the role of these microbes is evident in the petroleum-degradation process in cold marine environments, Abbreviations: PLFA, phospholipid fatty acid; ...

An aerobic, heterotrophic, Gram-negative, curved bacterial strain, designated MIL-1 T , was isolated by extinction dilution from an n-tetradecane enrichment culture that was established from sea water/sediment samples collected in the harbour of Milazzo, Italy. In the primary enrichment, the isolate formed creamy-white, medium-sized colonies on the surface of the agar. The isolate did not grow in the absence of NaCl; growth was optimal at 2?7 % NaCl. Only a narrow spectrum of organic compounds, including aliphatic hydrocarbons (C 7 -C 20 ), their oxidized derivatives and acetate, were used as growth substrates. The isolate was not able to grow under denitrifying conditions. The DNA G+C content and genome size of strain MIL-1 T were estimated to be 53?2 mol% and 2?2 Mbp, respectively. The major cellular and phospholipid fatty acids were palmitoleic, palmitic and oleic acids (33?5, 29?5 and 11?0 % and 18, 32 and 31 %, respectively). 3-Hydroxy lauric acid was the only hydroxy fatty acid detected. Thirteen different compounds that belonged to two types of phospholipid (phosphatidylethylamine and phosphatidylglycerol) were identified. 16S rRNA gene sequence analysis revealed that this isolate represents a distinct phyletic lineage within the c-Proteobacteria and has about 94?4 % sequence similarity to Oceanobacter kriegii (the closest bacterial species with a validly published name). The deduced protein sequence of the putative alkane hydrolase, AlkB, of strain MIL-1 T is related to the corresponding enzymes of Alcanivorax borkumensis and Pseudomonas oleovorans (81 and 80 % similarity, respectively). On the basis of the analyses performed, Thalassolituus oleivorans gen. nov., sp. nov. is described. Strain MIL-1 T (=DSM 14913 T =LMG 21420 T ) is the type and only strain of T. oleivorans.

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In San Biagio of Belpasso, approximately 20 km south of Mt. Etna, in the area of contact between volcanic and sedimentary formations, a number of small (3- 60 cm in diameter) active mud eruptions discharge CO2-rich gases, mud and NaCl brines. They can be described as mini-volcanoes owing to their typical conic shapes and continuously bubbling peak craters. Samples were collected from the active peak craters at a depth of 20 cm and DNA was immediately extracted and amplified with universal 16S rRNA gene-specific primers, followed by cloning procedure. A total of 140 bacterial clones obtained were screened and clustered by restriction fragment length polymorphism (RFLP) analysis. The pool of 16S rRNA sequences representing each RFLP cluster was subjected to phylogenetic analysis. All of the 33 sequences analysed were affiliated with the kingdom of Eubacteria; 28 sequences (77% of all clones) affiliated with the Proteobacteria, two sequences (19% of all clones) were affiliated with Actinobacteria and three sequences (4% of all clones) were affiliated with the Flexibacter-Cytophaga-Bacteroides division. The data obtained suggest that the microorganisms phylogenetically affiliated to autotrophic methane oxidizers and heterotrophic hydrocarbon degraders belonging to the gamma-subclass of Proteobacteria are major constituents of the microbial communities of the saline volcanic muds. Overall, the composition of the microbial community of the San Biagio mud volcano resembles the compositions of marine microbial communities, which might indicate that wind-blown seawater vapour acted as an inoculum for microbial community described in present work.

Aims: An analytical protocol has been developed and applied for the detection of glucuronidase activity in marine waters as a rapid alternative approach to assess the microbiological quality of seawaters. Methods and Results: The fluorogenic substrate 4-methylumbelliferyl-b-D-glucuronide is cleaved to a fluorescent product, methylumbelliferone, by the enzyme b-glucuronidase, specific to Escherichia coli and closely related enterobacterial species (Shigella). The results suggest that this test is related to E. coli numbers, as estimated by immunofluorescence, more significantly than to faecal coliform numbers, obtained from culture media. Conclusions: The determination of the potential rate of glucuronidase activity may be used as a diagnostic tool for the indirect estimation of the presence of E. coli in seawaters. Significance and Impact of the Study: The method may be particularly useful in the early warning of seawater pollution, allowing the screening of coastal areas with different contamination levels in reduced time.