PMID: 697499Jun 26, 1978Paper

Nitrate and nitrite reductase negative mutants of N2-fixing Azospirillum spp

Archives of Microbiology
L M MagalhãesJ Döbereiner

Abstract

Chlorate resistant spontaneous mutants of Azospirillum spp. (syn. Spirillum lipoferum) were selected in oxygen limited, deep agar tubes with chlorate. Among 20 mutants from A. brasilense and 13 from A. lipoferum all retained their functional nitrogenase and 11 from each species were nitrate reductase negative (nr-). Most of the mutants were also nitrite reductase negative (nir-), only 3 remaining nir+. Two mutants from nr+ nir+ parent strains lost only nir and became like the nr+ nir- parent strain of A. brasilense. No parent strain or nr+ mutant showed any nitrogenase activity with 10 mM NO3-. In all nr- mutants, nitrogenase was unaffected by 10 mM NO3-. Nitrite inhibited nitrogenase activity of all parent strains and mutants including those which were nir-. It seems therefore, that inhibition of nitrogenase by nitrate is dependent on nitrate reduction. Under aerobic conditions, where nitrogenase activity is inhibited by oxygen, nitrate could be used as sole nitrogen source for growth of the parent strains and one mutant (nr- nir-) and nitritite of the parent strains and 10 mutants (all types). This indicates the loss of both assimilatory and dissimilatory nitrate reduction but only dissimilatory nitrite reduction in the mutan...Continue Reading

References

Sep 1, 1976·Journal of Bacteriology·Y OkonR H Burris
Jan 1, 1976·Zeitschrift für allgemeine Mikrobiologie·K MotoharaM Ishimoto
Feb 1, 1977·Journal of Bacteriology·J D PaganA H Gibson
Mar 1, 1977·Canadian Journal of Microbiology·C A Neyra, J Döbereiner
Mar 1, 1977·Canadian Journal of Microbiology·C A Neyra, P Van Berkum
Dec 1, 1957·Biochimica Et Biophysica Acta·G M CHENIAE, H L EVANS
Jun 1, 1975·Proceedings of the National Academy of Sciences of the United States of America·J F Von Bülow, J Döbereiner

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Citations

Jan 1, 1980·Molecular & General Genetics : MGG·M PolsinelliE Gallori
Mar 1, 1982·Microbiological Reviews·R Knowles
Aug 30, 2005·Anais Da Academia Brasileira De Ciências·José I Baldani, Vera L D Baldani
Apr 1, 1983·Applied and Environmental Microbiology·C A Carlson, J L Ingraham
Sep 1, 1980·Microbiological Reviews·P van Berkum, B B Bohlool

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