Effects of nitrapyrin [2-chloro-6-(trichloromethyl)pyridine] on the obligate methanotroph Methylosinus trichosporium OB3b

Abstract

Nitrapyrin inhibited growth, CH4 oxidation, and NH4+ oxidation, but not the oxidation of CH3OH, HCHO, or HCOONa, by Methylosinus trichosporium OB3b, suggesting that nitrapyrin acts against the methane monooxygenase enzyme system. The inhibition of CH4 oxidation could be reversed by repeated washing of nitropyrin-inhibited cells, indicating that its effect is bacteriostatic. The addition of Cu2+ did not release the inhibition. Methane oxidation was also inhibited by 6-chloro-2-picoline. These data suggest that the mode of action of nitrapyrin on M. trichosporium is different from that on chemoautotrophic NH4+ oxidizers or methanogens.