title: Shewanella hafniensis sp. nov. and Shewanella morhuae sp. nov., isolated from marine fish of the Baltic Sea.
abstract: Two novel species belonging to the genus Shewanella are described on the basis of their phenotypic characteristics, phylogenetic analyses of 16S rRNA and gyrB gene sequences and levels of DNA-DNA hybridization. A total of 47 strains belonging to two novel Gram-negative, psychrotolerant, H2S-producing bacterial species were isolated from marine fish (cod and flounder) caught from the Baltic Sea off Denmark. The phenotypic characteristics of strains belonging to group 1 (14 strains) indicated that these represented a non-sucrose-assimilating variant of Shewanella baltica with a DNA G+C content of 47.0 mol%. Strains of group 2 (33 isolates) did not utilize the carbon substrates assimilated by S. baltica except gluconate, N-acetylglucosamine and malate. Their DNA G+C content was 44.0 mol%. Phylogenetic analysis of the 16S rRNA gene sequence data placed the two novel species within the genus Shewanella. Group 1 strains showed greatest sequence similarity to Shewanella putrefaciens ATCC 8071T (99.0 %) and with S. baltica NCTC 10375(T) (98.3 %). However, gyrB gene sequence analysis showed these isolates to share only 90.0 % sequence similarity with S. putrefaciens ATCC 8071T and 93.9 % with S. baltica NCTC 10375T. Similarly, DNA-DNA hybridization experiments revealed DNA relatedness levels of 38 % between the group 1 isolates and S. putrefaciens ATCC 8071T and 43 % with S. baltica NCTC 10375T. The group 2 strains shared less than 97 % 16S rRNA gene sequence similarities with recognized Shewanella species. Comparisons between the two novel species indicated 16S rRNA gene sequence similarity of approximately 98 %, gyrB gene sequence similarity of approximately 89 % and DNA-DNA reassociation values of 20-34 %. Based on the evidence presented, two novel species, Shewanella hafniensis sp. nov. (type strain P010T = ATCC BAA-1207T = NBRC 100975T) and Shewanella morhuae sp. nov. (type strain U1417T = ATCC BAA-1205T = NBRC 100978T), are described.
authors.affiliation: National Research Institute of Fisheries Science, Fisheries Research Agency, Yokohama, 236-8648, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Satomi
authors.forename: Birte Fonnesbech
authors.initials: BF
authors.lastname: Vogel
authors.forename: Lone
authors.initials: L
authors.lastname: Gram
authors.forename: Kasthuri
authors.initials: K
authors.lastname: Venkateswaran
mesh_terms: D000818:Animals; D001482:Base Composition; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry; D003718:Denmark; D005432:Flounder / Q000382:microbiology*; D048388:Gadiformes / Q000382:microbiology*; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D020592:Shewanella / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification / Q000502:physiology; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D027081:DNA Gyrase