We examined nitrate assimilation and root gas fluxes in a wild-type barley (Hordeum vulgare L. cv Steptoe), a mutant (nar1a) deficient in NADH nitrate reductase, and a mutant (nar1a;nar7w) deficient in both NADH and NAD(P)H nitrate reductases. Estimates of in vivo nitrate assimilation from excised roots and whole plants indicated that the nar1a mutation influences assimilation only in the shoot...

1. A soluble reduced Methyl Viologen-dependent assimilatory nitrate reductase from Azotobacter vinelandii strain UW136 grown aerobically on nitrate was purified to homogeneity by the criteria of nitrate reductase activity staining, and coincidence of a Coomassie Blue-staining protein band on polyacrylamide gels run under non-denaturing conditions. The specific activity was 3 mumol of NO2- forme...

abstract lettuce is one of the best accumulators of heavy metals and nitrate between leafy vegetables. through this research, it was tried to decreased cadmium absorption with humic acid (ha) and studies the effect of ha on the accumulation and metabolism of nitrate. plants were grown in the peat/perlite and irrigated with hoagland solution with addition of cadmium (2 and 4 mg l -1) and ha (100...

NADH-nitrate reductase (NR) from the primary leaves and root tips of corn seedlings (var. W64A x W182E) were activated by extracts from corn scutella. The activator extracted in potassium phosphate buffer (pH 7.5) or 80% (v/v) ethanol and fractionated by Dowex 1 (acetate) and Dowex 50 (H(+)) resins was recovered in the cationic fraction. The activator was not detected in extracts from shoots, r...

A NADH-hydroxypyruvate reductase was located in peroxisomes isolated from spinach leaves. The enzyme was precipitated by between 15 to 23 g of (NH4)$04 per 100 ml and had a pH optimum at 6.4. It was also akive with NADPH at a pH optimum of 5.1, and the NADH:NADPH ratio of maximum activity was about 13:l. The reductase with either NADH or NADPH was about 4.3-fold more active with hydroxypyruvate...

Plasma membranes obtained by two-phase partitioning of microsomal fractions from spinach (Spinacea oleracea L. cv Medania) and sugar beet leaves (Beta vulgaris L.) contained relatively high NADH-ferricyanide reductase and NADH-nitrate reductase (NR; EC 1.6.6.1) activities. Both of these activities were latent. To investigate whether these activities were due to the same enzyme, plasma membrane ...

The present study was conducted to investigate the allelopathic activity of Rumex dentatus aqueous leaf extract on metabolites, reactive oxygen species (ROS), and enzymes activities in Portulaca oleraceae. results showed a reduction carbohydrates, protein, DNA, RNA contents. However, total phenolics, flavonoids, malondialdehyde were enhanced. ROS such as hydrogen peroxide, superoxide radicals, ...

Mutants of Salmonella typhimurium that lack the biosynthetic sulfite reductase (cysI and cysJ mutants) retain the ability to reduce sulfite for growth under anaerobic conditions (E. L. Barrett and G. W. Chang, J. Gen. Microbiol., 115:513-516, 1979). Here we report studies of sulfite reduction by a cysI mutant of S. typhimurium and purification of the associated anaerobic sulfite reductase. Sulf...