title: Isolation and characterization of an early colonizing Rhizobium sp. R8 from a household toilet bowl.
abstract: The bacterial community structure was compared between the third days', one week', and three weeks' biofilm samples from the surface of a household toilet bowl. It was found that the PCR-DGGE band pattern of 16S rRNA gene was dramatically changed after the third day and was not further changed until three weeks. This result suggests that there are early and late colonizing bacterial groups. One of the early colonizers isolated from the third days' sample was Rhizobium sp. R8, a closest relative to Rhizobium giardinii, which exhibited the highest biofilm formation activity in an artificial urine condition. R8 produced extracellular polysaccharides containing galactose, glucose, and mannose at the molar ratio of 8:1:1, which were probably responsible for the biofilm formation. Its excelled biofilm formation and urease activities together with the lack of nodulation and nitrogen fixing genes in R8 suggest that this strain has been specifically adapted to urine condition in a toilet bowl.
authors.affiliation: a Graduate School of Environmental Science , Hokkaido University , Sapporo 060-0810 , Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Fukano
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Gomi
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Osaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Morikawa
mesh_terms: D001483:Base Sequence; D018441:Biofilms; D006794:Household Articles / Q000295:instrumentation; D059013:Microbial Consortia / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D012336:RNA, Ribosomal, 16S; D012231:Rhizobium / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D014510:Urease / Q000378:metabolism
chemical_list: D011135:Polysaccharides, Bacterial; D012336:RNA, Ribosomal, 16S; D014510:Urease
keywords: Rhizobium; biofilms; exopolysaccharides; toilet bowls; urease