Some eukaryotes, such as plant and fungi, are capable of utilizing nitrate as the sole nitrogen source. Once transported into the cell, nitrate is reduced to ammonium by the consecutive action of nitrate and nitrite reductase. How nitrate assimilation is balanced with nitrate and nitrite efflux is unknown, as are the proteins involved. The nitrate assimilatory yeast Hansenula polymorpha was use...

When tobacco is provided with a high nitrate supply, only a small amount of the nitrate taken up by the roots is immediately assimilated inside the roots, while the majority is transported to the leaves where it is reduced to ammonium. To elucidate the importance of root nitrate assimilation, tobacco plants have been engineered that showed no detectable nitrate reductase activity in the roots. ...

The inorganic aerosol system of sulfate, nitrate, and ammonium can respond non-linearly to changes in precursor sulfur dioxide (SO2) emissions. The potential increase in nitrate, when sulfate is reduced and the associated ammonia is released, can negate the sulfate mass reduction. Current regional-scale air quality models do not reproduce the present-day levels of total ammonia and total nitrat...

This study investigated differences in sensitivity to nitrate of soybean (Glycine max cv. Davis) symbioses with 16 different Rhizobium japonicum strains. When nitrate (20 mM) was added to established symbioses, there were no significant differences in the degree of inhibition of acetylene reduction for any of the 16 strains. When nitrate was present during the establishment of nodules, high lev...

In humans dietary circulating nitrate accumulates rapidly in saliva through active transport in the salivary glands. By this mechanism resulting salivary nitrate concentrations are 10-20 times higher than in plasma. In the oral cavity nitrate is reduced by commensal bacteria to nitrite, which is subsequently swallowed and further metabolized to nitric oxide (NO) and other bioactive nitrogen oxi...

Nitrate-reducing Fe(II)-oxidizing microorganisms were described for the first time ca. 20 years ago. Most pure cultures of nitrate-reducing Fe(II) oxidizers can oxidize Fe(II) only under mixotrophic conditions, i.e., when an organic cosubstrate is provided. A small number of nitrate-reducing Fe(II)-oxidizing cultures have been proposed to grow autotrophically, but unambiguous evidence for autot...

BACKGROUND Exposure to chemotherapeutic agents such as acetaminophen may lead to serious liver injury. Calcium deregulation, angiotensin II production and xanthine oxidase activity are suggested to play mechanistic roles in such injury. OBJECTIVE This study evaluates the possible protective effects of the calcium channel blocker amlodipine, the angiotensin converting enzyme inhibitor lisinopr...

The present interest in the determination of thiocyanate in serum, following the injection or ingestion of its salts, is twofold. First, in order to control hypertension by administering thiocyanate, the dosage must be regulated by frequently checking serum levels, as pointed out by Barker (1) and Wald, Lindberg, and Barker (2). Secondly, the determination of extracellular fluid, as originally ...