Abstract
Effects of the nucleic acid derivatives on the acid production of dairy lactic acid bacteria, including Streptococcus lactis, Str. cremoris, Str. thermophilus, Lactobacillus casei, L. acidophilus and L. bulgaricus, were investigated. It was found that the acid production of Lactobacilli was influenced by the addition of the nucleic acid derivatives to milk, but that of Lactic Streptococci was influenced little. There was a correlation between the structure of the nucleic acid derivatives and their effect on the acid production of Lactobacilli. Nucleic acid derivatives having pyrimidine base, except cytidine-mono-phosphate which had an inhibitory effect on the growth of L. bulgaricus, did not exert any significant influence on the growth of Lactobacilli. Nucleic acid derivatives having purine base had a great influence on the growth of Lactobacilli, especially on that of L. bulgaricus. Chemicals having adenosine and hypoxanthine base had a stimulative effect on the growth of L. bulgaricus, while chemicals having guanine base had an inhibitory effect. The increasing order of effectiveness of these chemicals was as follows: base<nucleoside<nucleotide.
The stimulative effect of adenosine-mono-phosphate and the inhibitory effect of guanosine-mono-phosphate were studied in more detail and their mechanisms were discussed.
