Isolation of bacteriophage active against all types of Mycobacterium tuberculosis.

in a combination of amino acids. It was subsequently found that a mixture of phenylalanine and cysteine promoted partial reversal of the inhibition, but that in the presence of a B vitamin supplement, the activity of the cysteine was less pronounced, whereas a mixture of phenylalanine and glutamic acid showed even greater activity. The activity of the vitamin supplement resided in its niacin and pantothenic acid content, as shown in table 1, in which the values represent the percentage of the growth obtained in identical cultures lacking the inhibitor. Growth was measured turbidimetrically after incubation for 16 hr at 37 C. Tyrosine and 3,4-dihydroxyphenylalanine were completely inactive. A mixture of pantothenate, niacin, glutamic acid, and phenylalanine gave 85 per cent release of the pipradrol inhibition, and nothing that we have been able to identify in the yeast extract further potentiated this effect.