Light-Induced Proton Release by the Cyanobacterium Anabaena variabilis

Bioenergetics Studies of the Cyanobacterium Anabaena variabilis

A cell-free system exhibiting both photophosphorylation (P /2e = 1) and oxidative phosphoryla­ tion (P/O up to 0 .8 ) is described for the cyanobacterium Anabaena variabilis. NADH and N A D PH were found to be equally effective as electron donors for oxidative phosphorylation. Low concentrations of U H D B T , an inhibitor of the cytochrome blc complex of mitochondria and chloroplasts. were fou...

RNA processing of nitrogenase transcripts in the cyanobacterium Anabaena variabilis.

Little is known about the regulation of nitrogenase genes in cyanobacteria. Transcription of the nifH1 and vnfH genes, encoding dinitrogenase reductases for the heterocyst-specific Mo-nitrogenase and the alternative V-nitrogenase, respectively, was studied by using a lacZ reporter. Despite evidence for a transcription start site just upstream of nifH1 and vnfH, promoter fragments that included ...

Components of the proton electrochemical potential gradient in Anabaena variabilis.

Effect of Monochromatic Light on Proton Efflux of the Blue-Green Alga Anabaena variabilis.

Light-induced proton efflux of Anabaena variabilis was found to be biphasic, the second phase being inhibited by the ATPase inhibitor nitrofen (2,4-dichloro-1-[4-nitrophenoxy]benzene). The first, fast phase was triggered by monochromatic light of 707 nanometers, whereas the second, slower phase was not. With 707 nanometers, light, respiratory O(2) uptake was inhibited. Using light composed of t...

Regulation of nitrogenase gene expression by transcript stability in the cyanobacterium Anabaena variabilis.

The nitrogenase gene cluster in cyanobacteria has been thought to comprise multiple operons; however, in Anabaena variabilis, the promoter for the first gene in the cluster, nifB1, appeared to be the primary promoter for the entire nif cluster. The structural genes nifHDK1 were the most abundant transcripts; however, their abundance was not controlled by an independent nifH1 promoter, but rathe...