title: Presence of two different active nirS nitrite reductase genes in a denitrifying Thauera sp. from a high-nitrate-removal-rate reactor.
abstract: The nirS nitrite reductase genes were studied in two strains (strains 27 and 28) isolated from two denitrifying reactors and characterized as Thauera according to their 16S rRNA gene sequences. Strain 28 contains a single nirS sequence, which is related to the nirS of Thauera mechernichensis, and strain 27 contains two nirS sequences; one is similar to the nirS sequence from Thauera mechernichensis (gene 2), but the second one (gene 8) is from a separate clade with nirS from Pseudomonas stutzeri, Azoarcus species, Alcaligenes faecalis, and other Thauera species. Both genes were expressed, but gene 8 was constitutively expressed while gene 2 was positively regulated by nitrate.
authors.affiliation: Cátedra de Microbiología, Facultad de Química, UDELAR, Gral. Flores 2124, CC 1157, Montevideo, Uruguay. cetchebe@fq.edu.uy
authors.forename: Claudia
authors.initials: C
authors.lastname: Etchebehere
authors.forename: James
authors.initials: J
authors.lastname: Tiedje
mesh_terms: D019149:Bioreactors; D004269:DNA, Bacterial / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D020628:Thauera / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D012336:RNA, Ribosomal, 16S; D009572:Nitrite Reductases