摘要

Most of the amino acids tested enhanced the growth of Tolypothrix scytonemoides (Gardner) Geitler at 1 mM, but at 10 mM these amino acids completely inhibited growth. The organism grew at both 1 and 10 mM of cysteine and methionine but when arginine, asparagine and aspartate were tested an inhibitory effect at both concentrations were observed. Maximum photosynthetic rate was observed in the presence of 1 mM tyrosine and respiratory rate was greatest in the presence of 1 mM valine. Aspartate, serine, threonine and tyrosine, at 1 mM caused complete inhibition of nitrogenase. The glutamine synthetase activity was highest in the cells of an unamended medium. The amount of exogenous carbohydrates was greatest in cells grown in the presence of 1 mM methionine. Considerably higher amounts of carbohydrates were also obtained with cells grown in 1 mM of glycine, histidine, lysine, phenylalanine, tryptophan, and 10 mM of methionine. Cells grown in asparagine, aspartate, serine, and threonine did not release carbohydrates.