Transcriptional regulation of Nostoc hydrogenases: Effects of oxygen, hydrogen, and nickel

The transcription of structural genes encoding two hydrogenases in N-2-fixing cultures of the cyanobacteria Nostoc muscorum and Nostoc sp. strain PCC 73102 were examined by reverse transcription-PCR. A low level of oxygen and addition of nickel induce higher transcript levels of both hydrogenases, whereas molecular hydrogen has a positive effect on the transcription of the genes encoding only the uptake hydrogenase.