Signal transduction protein P(II) is dephosphorylated in Synechocystis sp. strain PCC 6803 by protein phosphatase PphA. To determine the impact of PphA-mediated P(II) dephosphorylation on physiology, the phenotype of a PphA-deficient mutant was analyzed. Mutants lacking either PphA or P(II) were impaired in efficient utilization of nitrate as the nitrogen source. Under conditions of limiting ph...

The respiratory control of adhE, which encodes ethanol (alcohol) dehydrogenase in Escherichia coli, was examined at the transcriptional level by using various phi (adhE'-lacZ) adhE+ merodiploid strains. Expression of the adhE'-lacZ operon fusion was increased about eightfold by anaerobic growth. Under anaerobic growth conditions, provision of nitrate lowered the level of expression. Nitrate rep...

Reduction of nitrate takes place when the stored energy in the form of colour centres is released during dissolution of g-irradiated crystalline potassium fluoride in aqueous potassium nitrate solution. Various parameters like dose, amount and storage time of irradiated potassium fluoride which control the yield of nitrite have been studied. Similarly, the effect of concentration of potassium n...

Here, we investigate the functionality of the oxygen-responsive nitrogen regulation system NreABC in the human pathogen Staphylococcus aureus and evaluate its role in anaerobic gene regulation and virulence factor expression. Deletion of nreABC resulted in severe impairment of dissimilatory nitrate and nitrite reduction and led to a small-colony phenotype in the presence of nitrate during anaer...

Nitrate in food stuff can be reduced to nitrite and may form nitrosamines which are known as carcinogenic substances. Thus, its concentration has to be controlled by highly sensitive methods. In this work a new and fast differential pulse polarographic (DPP) method is established for the determination of nitrate. According to the reduction potentials V(II) was found most suitable for the reduct...

Preliminary work revealed that nitrate reductase in crude extracts prepared from leaves of certain corn genotypes as well as soybeans could utilize NADPH as well as NADH as the electron donor. Isoelectric focusing and diethylaminoethyl cellulose chromatography confirmed previous findings that NADH and NADPH activities could not be separated, which suggests the involvement of a single enzyme. Ni...

It was previously reported that three soybean (Glycine max [L.] Merr.) nodulation mutants (NOD1-3, NOD2-4, and NOD3-7) were partially tolerant to nitrate when nitrate was supplied simultaneously with inoculation at the time of transplanting. The current study evaluated the effect of short-term nitrate treatment on nitrogenase activity (C(2)H(2) reduction per plant and per nodule weight) and on ...

Five sets of microcosm batch experiments were performed to evaluate mechanisms of nitrate removal in constructed wetlands. The study evaluated biological denitrification activity as a function of 1) electron donors carbon and sulfur 2) wetland sediment depth 3) oxygen and abiotic reactions and 4) carbon addition and attached populations from wetland bulrushes. Wetland-water-only controls amende...