title: Isolation of novel bacteria and actinomycetes using soil-extract agar medium.
abstract: Novel bacteria were discovered using an isolation technique consisting of (i) selection of microorganisms that grew on soil-extract agar medium, but not on conventional media, and (ii) detection of small microbial colonies with a microscope. Three bacterial strains thus isolated were provisionally designated Shinshu-th1, -th2, -th 3, and five actinomycete strains, Shinshu-MS-01, -02, -03, -04, -05, respectively. Sequence analysis of their 16S rDNA showed that th1 had 95--96% homology with three unculturable bacteria, and th2 had 96% similarity to Bradyrhizobium sp., one unculturable and one unidentified bacterial strain. A phylogenetic study indicated that both strains were alpha-Proteobacteria belonging to the order Rhizobiales and the family Bradyrhizobiaceae. Since they had low homology (96%) with their close relatives, it is possible that th1 and th2 belong to a new genus. The actinomycetes Shinshu-MS-02 and -03 had 95--96% homology with four strains of Actinomadura, -04 had 95--96% similarity to Streptosporangium and Microbispora, and -05 had 97--98% homology with three strains of Acrocarpospora, Herbidospora and Planotetraspora. According to the phylogenetic study, both 02 and 03 are possibly new species of Actinomadura, -04 of Streptosporangium, and -05 of Acrocarpospora. Shinshu-th 3 and -MS-01 were identified as Mycobacterium cookii and Frankia sp., respectively, having 99% homology with these species.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Shinshu University, 8304 Minamiminowa, Kamiina, Nagano 399-4598, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Hamaki
authors.forename: Motomasa
authors.initials: M
authors.lastname: Suzuki
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Fudou
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Jojima
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kajiura
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: D039903:Actinobacteria / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D000362:Agar / Q000378:metabolism*; D041841:Bradyrhizobiaceae / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013045:Species Specificity
chemical_list: D012336:RNA, Ribosomal, 16S; D000362:Agar