Regulation of nitrogen fixation in Azospirillum brasilense
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چکیده
منابع مشابه
Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense.
NifA protein activates transcription of nitrogen fixation operons by the alternative sigma 54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS) located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST)-NifA fusion pr...
متن کامل(Methyl)ammonium transport in the nitrogen-fixing bacterium Azospirillum brasilense.
An ammonium transporter of Azospirillum brasilense was characterized. In contrast to most previously reported putative prokaryotic NH4+ transporter genes, A. brasilense amtB is not part of an operon with glnB or glnZ which, in A. brasilense, encode nitrogen regulatory proteins PII and PZ, respectively. Sequence analysis predicts the presence of 12 transmembrane domains in the deduced AmtB prote...
متن کاملRegulation of nitrogenase activity by oxygen in Azospirillum brasilense and Azospirillum lipoferum.
The nitrogenase activity of the microaerophilic bacteria Azospirillum brasilense and A. lipoferum was completely inhibited by 2.0 kPa of oxygen (approximately 0.02 atm of O2) in equilibrium with the solution. The activity could be partially recovered at optimal oxygen concentrations of 0.2 kPa. In contrast to the NH4+ switch off, no covalent modification of the nitrogenase reductase (Fe protein...
متن کاملIntermediary carbon metabolism of Azospirillum brasilense.
Azospirillum brasilense Sp 7 grew rapidly in AZO medium containing reduced nitrogen and succinate as an energy source, with a doubling time of 43 min. No growth was measured with glucose as the sole carbon source. In contrast, Azospirillum lipoferum Sp 59b could grow in media containing either succinate or glucose with a doubling time of 69 min and 223 min, respectively. Warburg-Barcroft respir...
متن کاملNH(4)-Excreting Azospirillum brasilense Mutants Enhance the Nitrogen Supply of a Wheat Host.
Spontaneous ethylenediamine-resistant mutants of Azospirillum brasilense were selected on the basis of their excretion of NH(4). Two mutants exhibited no repression of their nitrogenase enzyme systems in the presence of high (20 mM) concentrations of NH(4). The nitrogenase activities of these mutants on nitrogen-free minimal medium were two to three times higher than the nitrogenase activity of...
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ژورنال
عنوان ژورنال: FEMS Microbiology Letters
سال: 1997
ISSN: 0378-1097
DOI: 10.1016/s0378-1097(97)00187-0