title: Description of Shewanella glacialipiscicola sp. nov. and Shewanella algidipiscicola sp. nov., isolated from marine fish of the Danish Baltic Sea, and proposal that Shewanella affinis is a later heterotypic synonym of Shewanella colwelliana.
abstract: Two novel species belonging to the genus Shewanella are described on the basis of a polyphasic taxonomic approach. A total of 40 strains of Gram-negative, psychrotolerant, H2S-producing bacteria were isolated from marine fish (cod and plaice) caught in the Baltic Sea off Denmark. Strains belonging to group 1 (seven strains) were a lactate-assimilating variant of Shewanella morhuae with a G+C content of 44 mol%. The strains of group 2 (33 strains) utilized lactate, N-acetylglucosamine and malate but did not produce DNase or ornithine decarboxylase. Their G+C content was 47 mol%. Phylogenetic analysis of the 16S rRNA gene sequence data placed the two novel species within the genus Shewanella. Group 1 showed greatest sequence similarity with S. morhuae ATCC BAA-1205T (99.9 %). However, gyrB gene sequence analysis and DNA-DNA hybridization differentiated these isolates from S. morhuae, with 95.6 % sequence similarity and less than 57 % DNA relatedness, respectively. Group 2 strains shared more than 99 % 16S rRNA gene sequence similarity with the type strains of Shewanella colwelliana and Shewanella affinis, but gyrB sequence similarity ( approximately 85 %) and the results of DNA hybridization ( approximately 28 %) indicated that the new isolates represented a novel species. Furthermore, when compared to each other, the type strains of S. colwelliana and S. affinis had almost identical gyrB sequences and significantly high DNA reassociation values (76-83 %), indicating that they belonged to the same species. Based on the conclusions of this study, we propose the novel species Shewanella glacialipiscicola sp. nov. (type strain T147T=LMG 23744T=NBRC 102030T) for group 1 strains and Shewanella algidipiscicola sp. nov. (type strain S13T=LMG 23746T=NBRC 102032T) for group 2 strains, and we propose that Shewanella affinis as a later heterotypic synonym of Shewanella colwelliana.
authors.affiliation: National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama 236-8648, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Satomi
authors.affiliation: Danish Institute for Fisheries Research, Department of Seafood Research, Søltofts Plads, c/o Technical University of Denmark, Bldg 221, DK-2800 Kgs Lyngby, Denmark.
authors.forename: Birte Fonnesbech
authors.initials: BF
authors.lastname: Vogel
authors.affiliation: California Institute of Technology, Jet Propulsion Laboratory, Biotechnology and Planetary Protection Group, 89-2 Oak Grove Drive, Pasadena, CA 91109, USA.
authors.forename: Kasthuri
authors.initials: K
authors.lastname: Venkateswaran
authors.affiliation: Danish Institute for Fisheries Research, Department of Seafood Research, Søltofts Plads, c/o Technical University of Denmark, Bldg 221, DK-2800 Kgs Lyngby, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Gram
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D015373:Bacterial Typing Techniques; D001482:Base Composition; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003718:Denmark; D005399:Fishes / Q000382:microbiology*; D020459:Genes, rRNA; D006862:Hydrogen Sulfide / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D020592:Shewanella / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D008293:Malates; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; C030298:malic acid; D027081:DNA Gyrase; D000117:Acetylglucosamine; D006862:Hydrogen Sulfide