Cell growth and lincomycin production were measured in batch cultures of Streptomyces lincolnensis in chemically defined media. In these fermentations the specific rate of antibiotic production was maximal during growth and always declined at the end of the growth phase. It was found that both phosphate and ammonium salts, while required for cell growth, had negative effects on antibiotic produ...

Inhibition of purified AMP-deaminase from chicken breast muscle by phosphate esters and inorganic phosphate has been investigated. When tested at a concentration of 3 mM, in the presence of 0.15 M potassium chloride, the order of effectiveness as inhibitors of deaminase activity was: 2,3diphosphoglyceric acid, 3-phosphoglyceric acid, 2-phosphoglyceric acid, 2-phosphoenolpyruvate, fructose 1,6di...

The specific activities of enzymes catalyzing the ammonium-dependent carbamyl phosphate synthesis (NH(3)-CPS) and the glutamine-dependent carbamyl phosphate synthesis (GLN-CPS) were increased during germination by approximately 5-and 1.7-fold respectively in the presence of 35 mm urea. The increase of NH(3)-CPS and GLN-CPS levels occurred immediately after the onset of germination and prior to ...

Soybean cell suspension cultures grew on defined media with ammonium as the sole nitrogen source if Krebs cycle acids were added. Satisfactory growth was obtained with ammonium salts of citrate, malate, fumarate, or succinate, when compared with the regular medium containing nitrate and ammonium. Little or no growth occurred when ammonium salts of shikimate, tartrate, acetate, carbonate, or sul...

To understand the molecular interactions between N,N-dimethylformamide with two families of ionic liquids, the thermophysical properties such as densities and ultrasonic sound speeds have been measured over the entire composition range at 25 C under atmospheric pressure. The materials investigated in the present study include two families of ionic liquids, viz., ammonium salts and imidazolium s...

A method is presented for the efficient evaluation of long-range electrostatic forces in combined quantum mechanical and molecular mechanical (QM/MM) calculations of periodic systems. The QM/MM-Ewald method is a linear-scaling electrostatic method that utilizes the particle mesh Ewald algorithm for calculation of point charge interactions of molecular mechanical atoms and a real-space multipola...

Two ammonium-inducible, chloroplast-localized NADP-specific glutamate dehydrogenase isoenzymes were purified to homogeneity from Chlorella sorokiniana. These isoenzymes were homopolymers of either alpha- or beta-subunits with molecular weights of 55,500 or 53,000, respectively. The alpha-isoenzyme was preferentially induced at low ammonium concentrations (2 millimolar or lower), whereas only th...

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eli...

Thirty-nine soils from northern New South Wales were used to examine the effects of phosphate buffer capacity on (i) the extraction of labile phosphate by four soil tests, (ii) the relationships between the four soil tests, and (iii) the critical level of each soil test required for near-maximum yield of wheat under field conditions. The results confirmed the principle, recently proposed by the...