title: Occurrence and diversity of mesophilic Shewanella strains isolated from the North-West Pacific Ocean.
abstract: Although bacteria of the genus Shewanella belong to one of the readily cultivable groups of "Gammaproteobacteria", little is known about the occurrence and abundance of these microorganisms in the marine ecosystem. Studies revealed that of 654 isolates obtained from marine invertebrates (ophiuroid Amphiopholis kochii, sipuncula Phascolosoma japonicum, and holothurian Apostichopus japonicus, Cucumaria japonica), seawater and sediments of the North-West Pacific Ocean (i.e. the Sea of Japan and Iturup Is, Kurile Islands), 10.7% belonged to the genus Shewanella. The proportion of viable Shewanella species varied from 4% to 20% depending on the source of isolation. From the isolation study, representative strains of different phenotypes (from seventy presumptive Shewanella strains) were selected for detailed characterization using phenotypic, chemotaxonomic, and phylogenetic testing. 16S rDNA sequence-based phylogenetic analysis confirmed the results of tentative identification and placed the majority of these strains within only a few species of the genus Shewanella with 98-99% of 16S rDNA sequences identity mainly with S. japonica and S. colwelliana, suggesting that the strains studied might belong to these species. Numerically dominant strains of S. japonica were metabolically active and produced proteinases (gelatinases, caseinases), lipases, amylases, agarases, and alginases. Shewanella strains studied demonstrated weak antimicrobial and antifungal activities that might be an indication of their passive role in the colonization on living and non-living surfaces.
authors.affiliation: Pacific Institute of Bioorganic Chemistry of the Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia. eivanova@swin.edu.au
authors.forename: Elena P
authors.initials: EP
authors.lastname: Ivanova
authors.forename: Tomoo
authors.initials: T
authors.lastname: Sawabe
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Zhukova
authors.forename: Nataliya M
authors.initials: NM
authors.lastname: Gorshkova
authors.forename: Olga I
authors.initials: OI
authors.lastname: Nedashkovskaya
authors.forename: Karin
authors.initials: K
authors.lastname: Hayashi
authors.forename: Galina M
authors.initials: GM
authors.lastname: Frolova
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Sergeev
authors.forename: Konstantin G
authors.initials: KG
authors.lastname: Pavel
authors.forename: Valery V
authors.initials: VV
authors.lastname: Mikhailov
authors.forename: Dan V
authors.initials: DV
authors.lastname: Nicolau
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D005227:Fatty Acids / Q000032:analysis; D019015:Geologic Sediments / Q000382:microbiology; D007448:Invertebrates / Q000382:microbiology; D010140:Pacific Ocean; D010641:Phenotype; D010802:Phylogeny; D011809:Quinones / Q000032:analysis; D021521:Ribotyping; D012623:Seawater / Q000382:microbiology; D020592:Shewanella / Q000145:classification* / Q000302:isolation & purification; D013045:Species Specificity; D014871:Water Microbiology
chemical_list: D005227:Fatty Acids; D011809:Quinones