title: Crp-dependent cytochrome bd oxidase confers nitrite resistance to Shewanella oneidensis.
abstract: Shewanella oneidensis is able to respire on a variety of organic and inorganic substrates, including nitrate and nitrite. Conversion of nitrate to nitrite and nitrite to ammonium is catalysed by periplasmic nitrate and nitrite reductases (NAP and NRF) respectively. Global regulator Crp (cyclic AMP receptor protein) is essential for growth of S. oneidensis on both nitrate and nitrite. In this study, we discovered that crp mutants are not only severely deficient in nitrate or nitrite respiration, but are also hypersensitive to nitrite. This hypersusceptibility phenotype is independent of nitrite respiration. Using random transposon mutagenesis, we obtained 73 Δcrp suppressor strains resistant to nitrite. Transposon insertion sites in 24 suppressor strains were exclusively mapped in the region upstream of the cyd operon encoding a cytochrome bd oxidase, resulting in expression of the operon now driven by a Crp-independent promoter. Further investigation indicated that the promoter in suppressor strains comes from the transposon. Mutational analysis of the cydB gene (encoding the essential subunit II of the bd oxidase) confirmed that the cytochrome bd oxidase confers nitrite resistance to S. oneidensis.
authors: Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors: Huihui
authors: H
authors: Fu
authors: Haijiang
authors: H
authors: Chen
authors: Jixuan
authors: J
authors: Wang
authors: Guangqi
authors: G
authors: Zhou
authors: Haiyan
authors: H
authors: Zhang
authors: Lili
authors: L
authors: Zhang
authors: Haichun
authors: H
authors: Gao
mesh_terms: D000332:Aerobiosis / Q000502:physiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D049109:Cell Proliferation / Q000187:drug effects; D002373:Cyclic AMP Receptor Protein / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D004251:DNA Transposable Elements / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D023061:Gene Order; D008969:Molecular Sequence Data; D009566:Nitrates / Q000494:pharmacology; D009573:Nitrites / Q000494:pharmacology*; D009876:Operon / Q000235:genetics; D010100:Oxygen / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D020592:Shewanella / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002373:Cyclic AMP Receptor Protein; D004251:DNA Transposable Elements; D009566:Nitrates; D009573:Nitrites; D003576:Electron Transport Complex IV; D010100:Oxygen