A Gram-negative, non-motile, non-spore-forming, short rod-shaped bacterium (UST950701-009PT) was isolated from a marine biofilm in Hong Kong waters. Colonies are pink in colour, convex with a smooth surface and entire edge. Brown diffusible pigment is produced. Whitish colonies, with otherwise identical morphology, emerge from every culture upon ageing. The white colonies can be maintained as separate cultures (UST950701-009W) without turning pink. UST950701-009PT and UST950701-009W have identical 16S rRNA gene sequences and similar G+C (65·9–66·2 mol%) and fatty acid (86·22–88·52 % 18 : 1ω7c) contents. Phylogenetic analysis of the 16S rRNA gene sequence places UST950701-009PT within the Rhodobacter group of the α-subclass of the Proteobacteria. The nearest neighbours belong to the genus Loktanella, with similarity values ranging from 94·5 to 95·5 %. Data on G+C and fatty acid contents support the affiliation to the genus Loktanella. UST950701-009PT and -009W are heterotrophic, strictly aerobic and require NaCl for growth (2·0–14·0 %). Both grow in pH 5·0–10·0 and at 8–44 °C. Both are positive in oxidase, catalase and β-galactosidase tests, but they differ in the pattern of carbohydrate oxidation and assimilation. Molecular evidence together with phenotypic characteristics shows that UST950701-009PT constitutes a novel species within the genus Loktanella. The name Loktanella hongkongensis sp. nov. is proposed; the type strain is UST950701-009PT (=NRRL B-41039T=JCM 12479T) and a morphovar is UST950701-009W (=NRRL B-41040=JCM 12480).

) is proposed as the type strain of Roseivirga spongicola sp. nov. In an earlier study, it was suggested that the genus Marinicola is a later heterotypic synonym of the genus Roseivirga. However, a formal proposal to reclassify [Marinicola] seohaensis, the only member of the genus Marinicola, has not yet been made. The results of phylogenetic analyses in this study support the reclassification of [Marinicola] seohaensis as Roseivirga seohaensis comb. nov.Many marine sponges harbour large quantities of live bacteria. Bacterial numbers in sponges have been estimated to be as high as 10 8 cells (g tissue) 21 or up to 57 % of tissue volume (Hentschel et al., 2003). These bacteria can be maternal in origin or captured from sea water as the sponges filter feed (Imhoff & Stohr, 2003). The bacteria associated with sponges are believed to play essential roles in their survival and fitness. For example, the bioactive metabolitesThe GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains UST030701-097T and UST030701-084 T are DQ080995 and DQ080996, respectively. Tables detailing the results of API 20E, 20NE and 50CH tests and MicroLog 3 tests for strains UST030701-097 T and UST030701-084 T and scanning electron micrographs of cells of the two strains are available as supplementary material in IJSEM Online. G 2006 IUMS Printed in Great Britain

Many soft-bodied sessile marine invertebrates such as sponges and soft corals defend themselves against fouling directly through the production of antifouling compounds, or indirectly through regulating the epibiotic microbes that affect larval settlement. In this study, 10beta-formamidokalihinol-A and kalihinol A were isolated and purified from the marine sponge Acanthella cavernosa (Dendy). The results indicated that both compounds inhibited the growth of bacteria isolated from the natural environment whereas kalihinol A suppressed larval settlement of a major fouling polychaete, Hydroides elegans with an EC50 of 0.5 microg ml(-1). Kalihinol A was incorporated in Phytagel that was exposed to the bacterial consortia in natural seawater for biofilm formation. Biofilms that developed on the Phytagel surfaces were analysed for bacterial abundance and bacterial species composition using a DNA fingerprinting technique, terminal restriction fragment length polymorphism (T-RFLP). The results showed that kalihinol A only slightly reduced bacterial abundance (t-test, p = 0.0497), but modified the bacterial species composition of the biofilms. Inhibition of H. elegans larval settlement was observed when biofilms developed under the influence of kalihinol A were exposed to larvae, suggesting that compounds like kalihinol A from the sponge A. cavernosa may change bacterial community composition on the sponge surface, which in turn, modulates larval settlement of fouling organisms.