Cruz-García Claribel, Murray Alison E, Klappenbach Joel A, Stewart Valley, Tiedje James M
Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824-1325, USA.
J Bacteriol. 2007 Jan;189(2):656-62. doi: 10.1128/JB.01194-06. Epub 2006 Nov 10.
Anaerobic cultures of Shewanella oneidensis MR-1 grown with nitrate as the sole electron acceptor exhibited sequential reduction of nitrate to nitrite and then to ammonium. Little dinitrogen and nitrous oxide were detected, and no growth occurred on nitrous oxide. A mutant with the napA gene encoding periplasmic nitrate reductase deleted could not respire or assimilate nitrate and did not express nitrate reductase activity, confirming that the NapA enzyme is the sole nitrate reductase. Hence, S. oneidensis MR-1 conducts respiratory nitrate ammonification, also termed dissimilatory nitrate reduction to ammonium, but not respiratory denitrification.
以硝酸盐作为唯一电子受体培养的希瓦氏菌MR-1的厌氧培养物表现出硝酸盐依次还原为亚硝酸盐，然后再还原为铵。检测到少量的氮气和一氧化二氮，且在一氧化二氮上未发生生长。编码周质硝酸盐还原酶的napA基因缺失的突变体无法呼吸或同化硝酸盐，也不表达硝酸盐还原酶活性，这证实了NapA酶是唯一的硝酸盐还原酶。因此，希瓦氏菌MR-1进行呼吸性硝酸盐氨化作用，也称为异化硝酸盐还原为铵，但不进行呼吸性反硝化作用。
