Soybean (Gcine nax L. cv Williams) seeds were sown in pots containing a 1:1 perlite-vermiculite mixture and grown under greenhouse coditions. Nodules were initiated with a nitrate reductase expressing strain of Rhizobiumjaponicwn, USDA 110, or with nitrate reductase nonexpressing mutants (NR108, NR303) derived from USDA 110. Nodules initiated with either type of strain were normal in appearance...

The enzyme systems which catalyze the reduction of nitrate to nitrite have generally been classified into two broad types: (a) assimilatory nitrate reductase, which is responsible for the first step in the reduction of nitrate for the ultimate biosynthesis of nitrogen-containing cell constituents (e.g., amino acids aind purines and pyrimidines), and (b) respiratory or dissimilatory nitrate redu...

Assimilatory nitrate reductase was particle-bound in extracts from Azotobacter vinelandii. Nitrate reduction by particle fractions was dependent on NADPH and a particle-bound electron carrier. When the enzyme was solubilized from the particles by treatment with detergents, the particle-bound electron carrier could be substituted by ferredoxin or flavodoxin. Flavodoxin reduced at the expense of ...

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) compete for nitrate in natural and engineered environments. A known important factor in this microbial competition is the ratio of available electron donor and elector acceptor, here expressed as Ac/N ratio (acetate/nitrate-nitrogen). We studied the impact of the Ac/N ratio on the nitrate reduction pathways in chemostat enri...

Nitrate is a very important aerosol component, thus elucidation of its characteristics and formation mechanisms is essential and important for effective reduction of aerosol pollution. In this work, highly time-resolved submicron aerosol (PM1) data measured by Aerodyne aerosol mass spectrometers (AMS) in Nanjing, Beijing and Lanzhou during both summer and winter were integrated to investigate t...

The reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate oxidoreductase (EC 1.6.6.2) from Aspergillus nidulans was purified over 200-fold by use of salt fractionation, gel filtration, and ion-exchange chromatography. The purified enzyme was specific for NADPH and catalyzed reduction of nitrate, cytochrome c from isolated mitochondria of Aspergillus, and mammalian cytochrome c. An...

Ruminal methane production is among the main targets for greenhouse gas (GHG) mitigation for the animal agriculture industry. Many compounds have been evaluated for their efficacy to suppress enteric methane production by ruminal microorganisms. Of these, nitrate as an alternative hydrogen sink has been among the most promising, but it suffers from variability in efficacy for reasons that are n...

Nitrate uptake, reduction, and translocation were examined in intact, 14-day-old, nitrogen-depleted wheat (Triticum vulgare var. Knox) seedlings during a 9-hour exposure to 0.2 mm Ca (NO(3))(2). The nitrate uptake rate was low during the initial 3-hour period, increased during the 3- to 6-hour period, and then declined. By the 3rd hour, 14% of the absorbed nitrate had been reduced, and this inc...

The influence of nitrate and nitrite on growth of Corynebacterium glutamicum under aerobic conditions in shake flasks was analysed. When dissolved oxygen became limiting at higher cell densities, nitrate was reduced almost stoichiometrically to nitrite by nitrate reductase (NarGHJI). The nitrite concentration also declined slowly, presumably as a result of several reactions including reduction ...