Pelagicoccus mobilis gen. nov., sp. nov., Pelagicoccus albus sp. nov. and Pelagicoccus litoralis sp. nov., three novel members of subdivision 4 within the phylum 'Verrucomicrobia', isolated from seawater by in situ cultivation

1 Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-0032, Japan 2 Marine Biotechnology Institute Co. Ltd, 3-75-1 Heita, Kamaishi, Iwate 026-0001, Japan Correspondence Jaewoo Yoon aa57058{at}mail.ecc.u-tokyo.ac.jp Five Gram-negative, white-pigmented, spherical, chemoheterotrophic bacteria were isolated from seawater from Japan and the Republic of Palau by use of an in situ cultivation technique. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the five novel isolates, 02PA-Ca-133 T , YM14-201 T , H-MN57 T , H-MN48 and MN1-156, were closely affiliated to members of subdivision 4 within the phylum ‘ Verrucomicrobia ’. The novel isolates shared 96–100 % sequence similarity with each other and showed less than 90 % similarity with the cultivated strains of subdivision 4. DNA–DNA relatedness values between strains 02PA-Ca-133 T , YM14-201 T and H-MN57 T were less than 70 %; the value commonly accepted as the threshold for the phylogenetic definition of a species. Antibiotic susceptibility tests and amino acid analysis of cell-wall hydrolysates indicated that the novel isolates did not contain muramic acid or diaminopimelic acid in their cell walls, suggesting that these strains lack peptidoglycan. The DNA G+C contents of the five strains were 51–57 mol%. The major menaquinone was MK-7 and C 16 : 0 , C 16 : 1 7 c and anteiso-C 15 : 0 were the major fatty acids. On the basis of polyphasic taxonomic evidence, it is concluded that these strains should be classified as representing a new genus and three novel species in subdivision 4 of the phylum ‘ Verrucomicrobia ’, for which the names Pelagicoccus mobilis gen. nov., sp. nov. [type strain 02PA-Ca-133 T (=MBIC08004 T =IAM 15422 T =KCTC 13126 T )], Pelagicoccus albus sp. nov. [type strain YM14-201 T (=MBIC08272 T =IAM 15421 T =KCTC 13124 T )] and Pelagicoccus litoralis sp. nov. [type strain H-MN57 T (=MBIC08273 T =IAM 15423 T =KCTC 13125 T )] are proposed. Abbreviations: ONPG, o-nitrophenol - D -galactosidase; PUF, polyurethane foam; TEM, transmission electron microscopy The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains 02PA-Ca-133 T , YM14-201 T and H-MN57 T are AB286015 , AB286016 and AB286017 , respectively. Details of the composition of the ‘P’ medium used in the paper are available as supplementary material with the online version of this paper. Present address: Okinawa Prefecture Collaboration of Regi