Silicibacter pomeroyi sp. nov. and Roseovarius nubinhibens sp. nov., dimethylsulfoniopropionate-demethylating bacteria from marine environments

1 Departamento de Microbiología y Biología Celular, Facultad de Farmacia, Universidad de La Laguna, 38071 La Laguna, Tenerife, Spain 2 Departments of Marine Sciences, University of Georgia, Athens, GA 30602, USA 3 Departments of Microbiology, University of Georgia, Athens, GA 30602, USA 4 Institüt für Mikrobiologie, Universität Göttingen, 37077 Göttingen, Germany 5 Institüt für Biochemie, Genetik und Mikrobiologie, Universität Regensburg, D-93040 Regensburg, Germany 6 Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA 7 Department of Marine Sciences, University of South Alabama, Mobile, AL 36688, USA Correspondence Mary Ann Moran mmoran{at}uga.edu Three Gram-negative, rod-shaped, aerobic bacteria that were capable of degrading dimethylsulfoniopropionate (DMSP) were isolated from marine waters. These isolates (DSS-3 T , DSS-10 and ISM T ) exhibited the ability to demethylate and cleave DMSP, as well as to degrade other sulfur compounds related to DMSP that are cycled in marine environments. Intracellular poly- -hydroxybutyrate inclusions, surface blebs and one polar, complex flagellum that rotated exclusively in the clockwise direction were observed for DSS-3 T . The outer membrane of ISM T was separated from the cytoplasm at the poles in a toga-like morphology. The primary fatty acid in both strains was C 18 : 1 7 c . DNA G+C contents for the isolates were 68·0±0·1, 68·1±0·1 and 66·0±0·2 mol% for DSS-3 T , DSS-10 and ISM T , respectively. 16S rRNA gene sequence analyses placed these organisms within the Roseobacter lineage of the - Proteobacteria . Closely related species were Silicibacter lacuscaerulensis and Ruegeria atlantica (DSS-3 T and DSS-10) and Roseovarius tolerans (ISM T ). Neither DSS-3 T nor ISM T exhibited 16S rRNA similarity >97 % or DNA–DNA hybridization values >45 % to their nearest described relatives. Genotypic and phenotypic analyses support the creation of two novel species: Silicibacter pomeroyi sp. nov. with strain DSS-3 T (=ATCC 700808 T =DSM 15171 T ) as the type strain, and Roseovarius nubinhibens sp. nov. with strain ISM T (=ATCC BAA-591 T =DSM 15170 T ) as the type strain. Abbreviations: DMS, dimethylsulfide; DMSP, dimethylsulfoniopropionate;; ITS, internal transcribed spacer; MeSH, methanethiol; PHB, poly- -hydroxybutyrate Published online ahead of print on 7 February 2003 as DOI 10.1099/ijs.0.02491-0. The GenBank/EMBL/DDBJ accession numbers for the 16S rDNA sequences of strains DSS-