Biological nitrogen fixation (BNF) is the biological process by which the atmospheric nitrogen (N2) is converted to ammonia by an enzyme called nitrogenase. It is the major source of the biosphere nitrogen and as such has an important ecological and agronomical role, accounting for 65 % of the nitrogen used in agriculture worldwide. The most important source of fixed nitrogen is the symbiotic a...

The specific activity of Neurospora crassa glutamine synthetase varies according to the nitrogen source in which the organism is grown. In a poor nitrogen source such as glutamate, the specific activity of the enzyme is higher than that found in good nitrogen sources such as ammonium or glutamine. These differences in specific enzyme activity correspond to differences in enzyme concentration. T...

low grade grape juice concentrate was used as carbon source for xanthan production. significant factors affecting xanthan concentration, productivity and viscosity were investigated using plackett-burman design. based on the obtained results, carbon and nitrogen concentrations, inoculum size and agitation rate, were assumed as significant factors. broth culture viscosity and xanthan concentrati...

Simultaneous static-mode mass spectrometric measurements of nitrogen, carbon, helium, neon, and argon, extracted from the same aliquot of sample by high-resolution stepped combustion, have been made for a suite of five lunar soils. Noble gas isotope ratios show that the majority of noble gases are derived from a solar wind source; for example, at peak release temperatures of 500–600 C, Ne/Ne = ...

Problem statement: In today’s scenario, microalgae are widely recognized as a promising source for biofuel production as a renewable source of energy. They are exceedingly rich in oil, which can be converted to biofuel. This paper deals with one of the method to enhance the lipid content in microalgae. Approach: Microalga, Chlorella pyrenoidosa, was grown autotrophically in batch culture and th...

Background & Aims of the Study: In this research, Long-Term Hydrologic Impact Assessment model is selected for simulation of runoff and NPS pollution. The aim of this study is modeling of non-point source pollution by L-THIA model in Zayandehrood watershed in 2015. Materials & Methods: In this study, analytical survey and investigation of references in the context of libr...

Urease represents a critical virulence factor for some bacterial species through its alkalizing effect, which helps neutralize the acidic microenvironment of the pathogen. In addition, urease serves as a nitrogen source provider for bacterial growth. Pathogenic mycobacteria express a functional urease, but its role during infection has yet to be characterized. In this study, we constructed a ur...

The GATA family proteins Gln3p and Gat1p mediate nitrogen catabolite repression (NCR)-sensitive transcription in Saccharomyces cerevisiae. When cells are cultured with a good nitrogen source (glutamine, ammonia), Gln3p and Gat1p are restricted to the cytoplasm, whereas with a poor nitrogen source (proline), they localize to the nucleus, bind to the GATA sequences of NCR-sensitive gene promoters...