Classes of Anabaena variabilis mutants with oxygen-sensitive nitrogenase activity
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چکیده
منابع مشابه
The Effect of Activated Oxygen Species on Nitrogenase of Anabaena variabilis
The heterocyst-forming cyanobacterium Anabaena variabilis (ATCC 29413) is deficient in catalase activity, but especially heterocysts are rich in superoxide dismutase and peroxidases. It exhibits a light-dependent methylviologen-catalyzed oxygen uptake which is accompanied by a massive release o f hydrogen peroxide. Methylviologen caused a transient concentrationdependent inhibition o f nitrogen...
متن کاملRNA 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 ...
متن کاملCharacterization of genes for a second Mo-dependent nitrogenase in the cyanobacterium Anabaena variabilis.
Anabaena variabilis ATCC 29413 is a filamentous heterocystous cyanobacterium that fixes nitrogen under a variety of environmental conditions. Under aerobic growth conditions, nitrogen fixation depends upon differentiation of heterocysts and expression of either a Mo-dependent nitrogenase or a V-dependent nitrogenase in those specialized cells. Under anaerobic conditions, a second Mo-dependent n...
متن کاملCross-functionality of nitrogenase components NifH1 and VnfH in Anabaena variabilis.
Anabaena variabilis fixes nitrogen under aerobic growth conditions in differentiated cells called heterocysts using either a Mo nitrogenase or a V nitrogenase. The nifH1 gene, which encodes the dinitrogenase reductase of the Mo nitrogenase that is expressed only in heterocysts, is cotranscribed with nifD1 and nifK1, which together encode the Mo dinitrogenase. These genes were expressed in the p...
متن کاملThe Expression of a Third Nitrogenase in the Cyanobacterium Anabaena variabilis
Physiological experiments indicate that Anabaena variabilis can express either a Vor a Fe-nitrogenase in addition to the conventional, Mo-containing enzyme complex. The occur rence o f the Fe-nitrogenase in A. variabilis can also be concluded from D N A -D N A hybridiza tion experiments using cloned anfW or nifW probes coding for the smaller subunit (= nitroge nase reductase) o f the Fe-nitr...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1978
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.136.2.688-692.1978