Six strains of Gram-negative, rod-shaped, non-spore-forming bacteria were isolated from the Mediterranean Sea. 16S rRNA gene sequence analysis indicated that the strains were affiliated within the alphaproteobacterial genus Brevundimonas, with Brevundimonas intermedia (99?4 %) and Brevundimonas vesicularis (99?2 %) as their closest relatives. This affiliation was supported by chemotaxonomic data (major polar lipids: phosphatidyl diacylglycerol, sulfoquinovosyl diacylglycerol and phosphatidyl glucopyranosyl diacylglycerol; major fatty acids: C 18 : 1 , C 16 : 0 , C 16 : 1 , C 15 : 0 , C 17 : 1 v8c, 11-Me-C 18 : 1 v5t). The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of the strains from all recognized Brevundimonas species. The strains therefore represent a novel species, for which the name Brevundimonas mediterranea sp. nov. is proposed, with the type strain V4.BO.10 T (=LMG 21911 T =CIP 107934 T ).Two species originally described as Pseudomonas diminuta and Pseudomonas vesicularis were reclassified by Segers et al.(1994) into a new genus Brevundimonas with Brevundimonas diminuta as the type species of the genus. In 1999 several species were transferred from the genus Caulobacter to Brevundimonas and the description of the genus Brevundimonas was emended . Brevundimonas species are characterized and differentiated from Caulobacter species by the presence of certain glycoand polar lipids, outer-membrane proteins and an increased salt tolerance, but members of the genus show diverse cell morphologies and substrate specificities. Although some marine Brevundimonas strains have been described (Stahl et al., 1992;Yokoyama et al., 1996;Abraham et al., 2002), no marine Brevundimonas species has been named to date. Here we describe six strains isolated from marine water samples, which we propose are representatives of a novel species, Brevundimonas mediterranea sp. nov. SamplingMarine water samples were taken aboard the ship Thetys II

Arcicella aquatica NO-502 T , obtained from a neuston film on a freshwater lake and belonging to the phylum Bacteroidetes, is characterized by ring-forming cells. The bacterium is a strict aerobe, with optimal growth between 28 and 30 6C. Carbohydrates, but no organic acids or amino acids, are used as substrates. The G+C content of strain T From a freshwater neuston film a slow-growing bacterial isolate, NO-502 T , was obtained which formed rings consisting of several bacterial cells. Such a morphology is also known from some other bacterial genera, including Flectobacillus. In 1994, Nikitin and colleagues described this isolate as 'Arcocella aquatica' (Nikitin et al., 1994); however, no type species was deposited in a public culture collection and the description remained invalid. The aim of this note is to describe the genus and species validly and to give further information on the phylogenetic position of the type strain, NO-502Strain T was isolated on a medium containing 0?1 % peptone, yeast extract and glucose each at pH 7?0-7?2 from a neuston film of a freshwater lake near Moscow, Russia. Cells are polymorphic, showing vibrioid, curved and spiral-shaped cells.

No abstract

Nucleotide sequences of 5s ribosomal RNA (rRNA) isolated from 19 strains of Gram-negative methylotrophic bacteria were determined. Comparison of these sequences allowed construction of a tentative phylogenetic tree and showed that the bacteria analysed belong to the Proteobacteria and fell into several clusters, including obligate methanotrophs, obligate methylotrophs and several groups of facultative methylotrophs. Taxonomic relations between methylotrophic and non-methylotrophic bacteria are discussed, and the polyphyletic nature of methylotrophy as a taxonomic feature is highlighted.

No abstract