THE RELATION OF CALCIUM AND OTHER CONSTITUENTS OF A DEFINED MEDIUM TO PROLIFERATION OF LACTIC STREPTOCOCCUS BACTERIOPHAGE

Abstract

Using turbidity as a measure of S. lactis growth and the limiting dilution method in litmus milk (3 tubes per dilution) as an indication of bacteriophage multiplication, the omission of individual amino acids, purine and pyrimidine bases and vitamins from a defined medium affected similarly the multiplication of bacteria and bacteriophages of 2 S. lactis-bacteriophage combinations. Eight bacteriophages failed to multiply on their hosts in the defined medium, even in cases where the medium was supplemented with all of the completely characterized vitamins of the B complex and even after addition of yeast extract, tomato juice, and hydrolyzed casein. It then was discovered that when Ca was available, the completely defined medium supported the multiplication of these bacteriophages. In the medium supplemented with 0.1% CaCl2, it was necessary to prevent the loss of C by decreasing the K phosphate content to 0.1% and either sterilizing the complete medium by filtration or autoclaving the potassium phosphate separately from the other components.