Fifteen of 23 ATCC strains and 2 of 9 clinical isolates of Xanthomonas maltophilia, all of which grew aerobically on ammonia, but not nitrate, as a sole nitrogen source, reduced nitrate to nitrite. X. maltophilia failed to grow anaerobically on complex medium with or without nitrate, so it is considered an obligate aerobe. Nitrate-reducing strains contained reduced methyl viologen nitrate reduc...

Respiratory reduction of nitrate and nitrite is encoded in Thermus thermophilus by the respective transferable gene clusters. Nitrate is reduced by a heterotetrameric nitrate reductase (Nar) encoded along transporters and regulatory signal transduction systems within the nitrate respiration conjugative element (NCE). The nitrite respiration cluster (nic) encodes homologues of nitrite reductase ...

Klebsiella aerogenes W70 could grow aerobically with nitrate or nitrite as the sole nitrogen source. The assimilatory nitrate reductase and nitrite reductase responsible for this ability required the presence of either nitrate or nitrite as an inducer, and both enzymes were repressed by ammonia. The repression by ammonia, which required the NTR (nitrogen regulatory) system (A. Macaluso, E. A. B...

Induction, energy gain, effect on growth, and interaction of nitrate and nitrite reduction of Bradyrhizobium sp. (Lupinus) USDA 3045 were characterized. Both nitrate and nitrite were reduced in air, although nitrite reduction was insensitive to ammonium inhibition. Anaerobic reduction of both ions was shown to be linked with energy conservation. A dissimilatory ammonification process was detect...

It is becoming recognized that leghaemoglobin constitutes an important buffer for the cytotoxic nitric oxide radical (NO(*)) in root nodules, although the sources of this NO(*) within nodules are unclear. In Bradyrhizobium japonicum bacteroids, NO(*) can be produced through the denitrification process, during which nitrate is reduced to nitrite by the periplasmic nitrate reductase Nap, and nitr...

Intragenic complementation has been observed between apoenzyme nitrate reductase-deficient mutants (nia) of Nicotiana plumbaginifolia. In vivo as in vitro, the NADH-nitrate reductase (NR) activity in plants heterozygous for two different nia alleles was lower than in the wild type plant, but the plants were able to grow on nitrate as a sole nitrogen source. NR activity, absent in extracts of ho...

narK mutants of Escherichia coli produce wild-type levels of nitrate reductase but, unlike the wild-type strain, do not accumulate nitrite when grown anaerobically on a glucose-nitrate medium. Comparison of the rates of nitrate and nitrite metabolism in cultures growing anaerobically on glucose-nitrate medium revealed that a narK mutant reduced nitrate at a rate only slightly slower than that i...

Mycobacterium fortuitum and Mycobacterium chelonei are distinguished unambiguously by the combined use of five test characters: nitrate reductase, beta-glucosidase, acid production from fructose, penicillinase, and trehalase. Typically, M. fortuitum was nitrate reductase positive, beta-glucosidase positive; M. chelonei was nitrate reductase negative, beta-glucosidase negative, penicillinase pos...

A comparative study has been carried out of the growth of two lines of Datura innoxia (Mill.) cells, designated DI-6 and NR1, their resistance to chlorate, and their ability to assimilate nitrate in sterile culture. The NR1 cell line was isolated from DI-6 cultures by first growing the latter in a nitrate-based medium for 5 days and then transferring the cells to a medium containing 2 grams lit...