Chlorate resistant mutants of Pseudomonas stutzeri affected in respiratory and assimilatory nitrate utilization and expression of cytochrome cd1 |
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Authors: | Walter G. Zumft,Sandor Blü mle,Cornelia Braun,Heinz Kö rner |
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Affiliation: | Lehrstuhl für Mikrobiologie, Universität Karlsruhe, Karlsruhe, F.R.G. |
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Abstract: | Abstract Chlorate-resistant mutants were generated by random insertion of the transposon Tn5 into genomic DNA of Pseudomonas stutzeri ZoBell strain and selected for loss of nitrate respiration (Nar phenotype). The mutants were differentiated by restriction-fragment analysis, by assaying for nitrate assimilation and for molybdenum co-factor activity, and by the amount of respiratory nitrate reductase. Two mutants, lacking both nitrate respiration and nitrate assimilation, over-produced an inactive nitrate reductase but synthesized in the presence of nitrate only a reduced amount of respiratory nitrite reductase (cytochrome cd 1). Expression of cytochrome cd 1 in these mutants was specifically induced by nitrate, suggesting a sensor system for this substrate. |
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Keywords: | Pseudomonas stutzeri Nitrite sensor Denitrification Respiratory nitrite reductase Molybdenum co-factor Transposon Tn5 Chlorate resistance |
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