The fission yeast Schizosaccharomyces pombe undergoes a switch from yeast to filamentous invasive growth in response to certain environmental stimuli. Among them is ammonium limitation. Amt1, one of the three ammonium transporters in this yeast, is required for the ammonium limitation-induced morphological transition; however, the underlying molecular mechanism remains to be understood. Cells l...

The ammonium permease Mep2 induces a switch from unicellular yeast to filamentous growth in response to nitrogen limitation in Saccharomyces cerevisiae and Candida albicans. In S. cerevisiae, the function of Mep2 and other ammonium permeases depends on the protein kinase Npr1. Mutants lacking NPR1 cannot grow on low concentrations of ammonium and do not filament under limiting nitrogen conditio...

In this study we examined the mechanism by which ammonium bicarbonate inhibits mycotoxigenic fungi. Elevated extracellular pH, alone, was not responsible for the antifungal activity. Although conidia of Penicillium griseofulvum and Fusarium graminearum had internal pH (pHi) values as high as 8.0 in buffer at an external pH (pHo) of 9.5, their viability was not markedly affected. The pHi values ...

1. We used two separate approaches to estimate ambient ammonium cycling in the north and south branches of Kings Creek, a prairie stream. Chamber experiments were conducted to determine ammonium uptake and mineralization rates associated with epilithic biofilms and filamentous algae collected from the streams. A series of short-term whole-stream ammonium addition experiments were also conducted...

in order to study a the effect of different levels of ammonium sulfate on photosynthesis pigments, essential oil content and components in summer savory, an experiment was conducted based on randomized complete block design (rcbd) with five treatments and three replications on karaj climate conditions. the treatments included five levels of ammonium sulfate consist of: control (without fertiliz...

hours to several days. We changed the concentration of ammonium hydroxide from 1 mmol/L to 2 mmol/L. We again prepared a standard solution of uric acid at the same molar ratio of 1.7:1 with this concentration of 2-mmol/L ammonium hydroxide. With this ammonium hydroxide concentration, uric acid dissolved completely in a few minutes. The standard solution was stable at least 3 months stored in a ...

l-Glutamate uptake, thiourea uptake, and methylammonium uptake and the intracellular ammonium concentration were measured in wild-type and mutant cells of Aspergillus nidulans held in various concentrations of ammonium and urea. The levels of l-glutamate uptake, thiourea uptake, nitrate reductase, and hypoxanthine dehydrogenase activity are determined by the extracellular ammonium concentration...

animal models for h.pylori infection have been developed to clarify the pathogenesis, testing new therapies and developing vaccines against human h.pylori infection. although rats have been used extensively for gastric ulceration and acid secretion studies, the animal is not normally infected with h.pylori.several chemicals such as ethanol and ammonium hydroxide can induce gastric erosion and i...

Ammonium and nitrate are the prevalent nitrogen sources for growth and development of higher plants. 15N-uptake studies demonstrated that ammonium is preferred up to 20-fold over nitrate by Arabidopsis plants. To study the regulation and complex kinetics of ammonium uptake, we isolated two new ammonium transporter (AMT) genes and showed that they functionally complemented an ammonium uptake-def...