Thermodynamic models predict that sulfate aerosol (S(VI) ≡ H2SO4(aq)+HSO−4 +SO 2− 4 ) should take up available ammonia (NH3) quantitatively as ammonium (NH+4 ) until the ammonium sulfate stoichiometry (NH4)2SO4 is close to being reached. This uptake of ammonia has important implications for aerosol mass, hygroscopicity, and acidity. When ammonia is in excess, the ammonium–sulfate aerosol ratio ...

A series of polymerizable quaternary ammonium compounds were synthesized with the aim of using them as immobilized antibacterial agents in methacrylate dental composites, and their structures were characterized by FT-IR, (1)H-NMR, and (13)C-NMR analysis. Their antibacterial activities against the oral bacterium Streptococcus mutans were evaluated in vitro by a Minimum Inhibitory Concentration t...

The title compound, C(36)H(30)NP(2) (+)·I(-), was obtained accidently from crystallization of a reaction mixture containing [(Ph(3)P)(2)N]OH and B(OH)(3), which was contaminated with MeI. There are two independent [(Ph(3)P)(2)N](+) cations and two I(-) anions within the asymmetric unit. The central PNP angles are non-linear [137.6 (2) and 134.4 (2)°] and the phenyl substituents on P centres ado...

The reaction of 1-naphthyl-methyl-amine and hydro-chloric acid in a 1:1 molar ratio resulted in the formation of the 1:1 proton-transfer compound, C(11)H(12)N(+)·Cl(-). In the crystal, the ions are linked by N-H⋯Cl hydrogen bonds into a sheet pattern in the ab plane such that each Cl(-) ion is bonded to three NH groups from the naphthylmethylammonium ion.

A standard diet was supplemented with ammonium acetate (20%, w/w). The effect on liver protein degradation of oral administration of the ammonium diet to rats for 6 weeks has been studied. It is shown that lysosomal proteolysis is markedly decreased (by 62%) while non-lysosomal proteolysis is inhibited by 11%. This is the first report showing that ammonium ingestion inhibits liver proteolysis.

The niaD gene of the fungus Aspergillus nidulans encodes an assimilatory nitrate reductase and exogenous ammonium represses its expression. Under anoxic conditions, however, A. nidulans expressed niaD even in the presence of ammonium and used the gene product for dissimilatory nitrate reduction (ammonia fermentation). This transcription regulation mechanism under anaerobiosis is critical for th...

New evidences have recently emerged from studies in yeast and in higher eukaryotes showing the importance of nutrient balance in dietary regimes and its effects on longevity regulation.We have previously shown that manipulation of ammonium concentration in the culture and/or aging medium can drastically affect chronological lifespan (CLS)of Saccharomyces cerevisiae, especially in amino acid res...

In response to nitrogen starvation, diploid cells of the budding yeast Saccharomyces cerevisiae differentiate into a filamentous, pseudohyphal growth form. This dimorphic transition is regulated by the Galpha protein GPA2, by RAS2, and by elements of the pheromone-responsive MAP kinase cascade, yet the mechanisms by which nitrogen starvation is sensed remain unclear. We have found that MEP2, a ...

Cyanide assimilation by the beta-cyanoalanine pathway produces asparagine, aspartate and ammonium, allowing cyanide to serve as alternate or supplemental source of nitrogen. Experiments with wheat and sorghum examined the enrichment of (15)N from cyanide as a function of external cyanide concentration in the presence or absence of nitrate and/or ammonium. Cyanogenic nitrogen became enriched in ...