Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath Export

@article{citeulike:3759692, abstract = {Methylococcus capsulatus strain Bath, a methane-oxidizing bacterium, and ammonia-oxidizing bacteria (AOB) carry out the first step of nitrification, the oxidation of ammonia to nitrite, through the intermediate hydroxylamine. AOB use hydroxylamine oxidoreductase (HAO) to produce nitrite. M. capsulatus Bath was thought to oxidize hydroxylamine with cytochrome P460 (cytL), until the recent discovery of an hao gene in its genome. We used quantitative PCR analyses of cDNA from M. capsulatus Bath incubated with CH4 or CH4 plus 5 mM (NH4)2SO4 to determine whether cytL and hao transcript levels change in response to ammonia. While mRNA levels for cytL were not affected by ammonia, hao mRNA levels increased by 14.5- and 31-fold in duplicate samples when a promoter proximal region of the transcript was analyzed, and by sixfold when a region at the distal end of the transcript was analyzed. A conserved open reading frame, orf2, located 3' of hao in all known AOB genomes and in M. capsulatus Bath, was cotranscribed with hao and showed increased mRNA levels in the presence of ammonia. These data led to designating this gene pair as haoAB, with the role of haoB still undefined. We also determined mRNA levels for additional genes that encode proteins involved in N-oxide detoxification: cytochrome c'-beta (CytS) and nitric oxide (NO) reductase (NorCB). Whereas cytS mRNA levels increased in duplicate samples by 28.5- and 40-fold in response to ammonia, the cotranscribed norC-norB mRNA did not increase. Our results strongly suggest that M. capsulatus Bath possesses a functional, ammonia-responsive HAO involved in nitrification.}, author = {Poret-Peterson, Amisha T. and Graham, James E. and Gulledge, Jay and Klotz, Martin G.}, citeulike-article-id = {3759692}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/ismej.2008.71}, citeulike-linkout-1 = {http://dx.doi.org/10.1038/ismej200871a}, day = {24}, doi = {10.1038/ismej.2008.71}, journal = {ISME J}, keywords = {evolution, hao, methanotrophy, methylococcus, nitrification, qpcr}, month = {July}, number = {12}, pages = {1213--1220}, posted-at = {2008-12-09 14:46:54}, priority = {2}, publisher = {International Society for Microbial Ecology}, title = {Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath}, url = {http://dx.doi.org/10.1038/ismej.2008.71}, volume = {2}, year = {2008} }

TY - JOUR ID - citeulike:3759692 L3 - citeulike-article-id:3759692 N2 - Methylococcus capsulatus strain Bath, a methane-oxidizing bacterium, and ammonia-oxidizing bacteria (AOB) carry out the first step of nitrification, the oxidation of ammonia to nitrite, through the intermediate hydroxylamine. AOB use hydroxylamine oxidoreductase (HAO) to produce nitrite. M. capsulatus Bath was thought to oxidize hydroxylamine with cytochrome P460 (cytL), until the recent discovery of an hao gene in its genome. We used quantitative PCR analyses of cDNA from M. capsulatus Bath incubated with CH4 or CH4 plus 5 mM (NH4)2SO4 to determine whether cytL and hao transcript levels change in response to ammonia. While mRNA levels for cytL were not affected by ammonia, hao mRNA levels increased by 14.5- and 31-fold in duplicate samples when a promoter proximal region of the transcript was analyzed, and by sixfold when a region at the distal end of the transcript was analyzed. A conserved open reading frame, orf2, located 3' of hao in all known AOB genomes and in M. capsulatus Bath, was cotranscribed with hao and showed increased mRNA levels in the presence of ammonia. These data led to designating this gene pair as haoAB, with the role of haoB still undefined. We also determined mRNA levels for additional genes that encode proteins involved in N-oxide detoxification: cytochrome c'-beta (CytS) and nitric oxide (NO) reductase (NorCB). Whereas cytS mRNA levels increased in duplicate samples by 28.5- and 40-fold in response to ammonia, the cotranscribed norC-norB mRNA did not increase. Our results strongly suggest that M. capsulatus Bath possesses a functional, ammonia-responsive HAO involved in nitrification. IS - 12 JF - ISME J EP - 1220 TI - Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath PB - International Society for Microbial Ecology VL - 2 SP - 1213 KW - evolution KW - hao KW - methanotrophy KW - methylococcus KW - nitrification KW - qpcr AU - Poret-Peterson, Amisha AU - Graham, James AU - Gulledge, Jay AU - Klotz, Martin PY - 2008/07/24/ UR - http://dx.doi.org/10.1038/ismej.2008.71 ER -