2024-03-29T06:30:17Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/400612022-11-17T02:08:08Zhdl_2115_20051hdl_2115_144Detection of UVBR-sensitive and -tolerant bacteria in surface waters of the western North PacificKataoka, TakafumiHodoki, YoshikuniSuzuki, KojiSaito, HiroakiHigashi, SeigoUVBRThymine dimerPhylotypeDGGEImmunocaptureMarine bacteria431In order to evaluate the effects of solar ultraviolet radiation (UVR) on eubacterial community composition, we examined the tolerance of eubacterial phylotypes to solar UV radiation in surface waters of the western North Pacific during September 2005. Bromodeoxyuridine (BrdU), a halogenated thymine analogue, was used for labeling newly synthesized DNA in proliferating cells. Thymine dimers (TD), which are specifically formed in DNA by biologically harmful ultraviolet B radiation (UVBR; 280-315 nm), were also applied to detect UVB damaged genomes selectively. PCR-denaturing gradient gel electrophoresis (PCR-DGGE) on the labeled samples revealed that UVBR-resistant cells showing active synthesis of DNA without accumulating TD, varied among phylotypes. In addition, UVBR-sensitive band positions with TD indicated inter-specific variations in sensitivity to UVBR. Phylogenetic analysis revealed that 12 DNA sequences were classified into 8 phylogenetic groups: 3 Rosecbacter, 1 Sphingomonas, 2 Gammaproteobacteria, 1 Actinobacteria, 1 Synechococcus, 2 Prochlorococcus, 1 plastid and 1 another group. A UVBR-resistant phylotype was affiliated to Erythrobacter sp. (previously designated as Sphingomonas sp.), which was distributed in warmer waters from the south of Oyashio to Kuroshio regions. A UVBR-sensitive phylotype was affiliated to Pseudoalteromonas sp. in Gammaproteobacteria. Dominant heterotrophic eubacteria were composed of both sensitive and resistant phylotypes. This is the first report on TD accumulated eubacterial phylotypes in oceanic surface waters.Elsevier B.V.Journal Articleapplication/pdfhttp://hdl.handle.net/2115/40061https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/40061/1/JPPB95-2_108-116.pdf1011-1344Journal of Photochemistry and Photobiology B : Biology9521081162009-05-04enginfo:pmid/19285879info:doi/10.1016/j.jphotobiol.2009.02.004author