EVIDENCE FOR A REGULATORY LINK OF NITROGEN-FIXATION AND PHOTOSYNTHESIS IN RHODOBACTER-CAPSULATUS VIA HVRA

Citation
M. Kern et al., EVIDENCE FOR A REGULATORY LINK OF NITROGEN-FIXATION AND PHOTOSYNTHESIS IN RHODOBACTER-CAPSULATUS VIA HVRA, Journal of bacteriology, 180(7), 1998, pp. 1965-1969
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ISSN journal
0021-9193
Volume
180
Issue
7
Year of publication
1998
Pages
1965 - 1969
Database
ISI
SICI code
0021-9193(1998)180:7<1965:EFARLO>2.0.ZU;2-Y
Abstract
A Rhodobacter capsulatus reporter strain, carrying a constitutively ex pressed nifA gene and a nifH-lacZ gene fusion, was used for random tra nsposon Tn5 mutagenesis to search for genes required for the NtrC-inde pendent ammonium repression-of NifA activity. A mutation in hvrA, whic h is known to be involved in low-light activation of the photosyntheti c apparatus, released both ammonium and oxygen control of nifH express ion in this reporter strain, demonstrating a regulatory link of nitrog en fixation and photosynthesis via HvrA In addition, a significant inc rease in bacteriochlorophyll a (BChla) content was found in cells unde r nitrogen-fixing conditions. HvrA was not involved in this up-regulat ion of BChla. Instead, the presence of active nitrogenase seemed to be sufficient for this process, since no increase in BChla content was o bserved in different nif mutants.