Evidence for a Regulatory Link of Nitrogen Fixation and Photosynthesis in Rhodobacter capsulatus via HvrA
AUTOR(ES)
Kern, Monika
FONTE
American Society for Microbiology
RESUMO
A Rhodobacter capsulatus reporter strain, carrying a constitutively expressed nifA gene and a nifH-lacZ gene fusion, was used for random transposon Tn5 mutagenesis to search for genes required for the NtrC-independent ammonium repression of NifA activity. A mutation in hvrA, which is known to be involved in low-light activation of the photosynthetic apparatus, released both ammonium and oxygen control of nifH expression in this reporter strain, demonstrating a regulatory link of nitrogen fixation and photosynthesis via HvrA. In addition, a significant increase in bacteriochlorophyll a (BChla) content was found in cells under nitrogen-fixing conditions. HvrA was not involved in this up-regulation of BChla. Instead, the presence of active nitrogenase seemed to be sufficient for this process, since no increase in BChla content was observed in different nif mutants.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=107117Documentos Relacionados
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