title: Rare bacterium of new genus isolated with prolonged enrichment culture.
abstract: Dynamic change in microbial flora was monitored with an oxygen electrode. The 1st phase microorganisms, which first grew well in LB medium, were followed by the 2nd phase microorganisms, which supposedly assimilated microbial cells of the 1st phase and their metabolites. In a similar way, a change in microbial flora was observed from the 1st phase to the 4th phase in 84 hr. Based on this observation, prolonged enrichment culture was done for as long as two months to increase the ratio of existence of rare microorganisms. From these culture liquids, four slow-growing bacteria (provisionally named Shinshu-ah1, -ah2, -ah3, and -ah4), which formed scarcely visible small colonies, were isolated. Sequence analysis of their 16S rDNA showed that Shinshu-ah1 had 97% homology with Bradyrhizobium japonicum and uncultured alpha proteobacterium clone blaii 16, Shinshu-ah2 91% with Rasbo bacterium, Alpha proteobacterium 34619, Bradyrhizobium genosp. P, Afipia felis and an unidentified bacterium, Shinshu-ah3 99% with Methylobacterium mesophilicum, and Shinshu-ah4 95% with Agromyces ramosus DSM 43045. Phylogenetic study indicated that Shinshu-ah2 had a possibility to form a new family, Shinshu-ah1 a new genus, and Shinshu-ah4 a new species.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Shinshu University, Minamiminowa, Nagano, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Hashizume
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Fudou
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Jojima
authors.forename: Ryohsuke
authors.initials: R
authors.lastname: Nakai
authors.forename: Akira
authors.initials: A
authors.lastname: Hiraishi
authors.forename: Akira
authors.initials: A
authors.lastname: Tabuchi
authors.forename: Kikuo
authors.initials: K
authors.lastname: Sen
authors.forename: Hiroshiro
authors.initials: H
authors.lastname: Shibai
mesh_terms: D020622:Afipia / Q000235:genetics; D001431:Bacteriological Techniques / Q000379:methods*; D020369:Bradyrhizobium / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D002455:Cell Division; D003470:Culture Media; D004275:DNA, Ribosomal / Q000235:genetics; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D020580:Methylobacterium / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010100:Oxygen; D010802:Phylogeny; D020560:Proteobacteria / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S; D012689:Sequence Homology, Nucleic Acid
chemical_list: D003470:Culture Media; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D010100:Oxygen