Studies on the Tryptophan Metabolism of Bacteria II. Tryptophan metabolism of B. typhosus

It is well known that tryptophan is necessary for the growth of B. typhosus. The anthor analyzed this requirement of tryptophan from the point of view of the nutritive requirement of B. typhosus. The results were as follows: 1) Of ten strains, seven strains require tryptophan for growth, three strains do not. 2) S-58 which requires tryptophan utilizes no amino acid singlely as N source and S-60 which does not require tryptophan utilizes singlely glutamic acid, cystine and aspartic acid. Glutamic acid is especially utilized by S-60. 3) S-58 does not grow in the absence of tryptophan and grows scarcely in the absence of cystine and grows a little in the absence of aspartic acid. On the contrary S-60 grows in the presence or absence of tryptophan and grows scarcely in the absence of cystine and grows a little in fhe absence of aspartic acid. 4) Tryptophan has the effect on growth at 10(-8) Mol. From this and the fact that above mensioned the strain which requires tryptophan could not grow in the absence of tryptophan tryptophan is fouud to be “growth factor” fot the strain. 5) Indole is found to be approximately equally effective as tryptophan. 6) Indole acetic acid and skatole is more weak effective compared with indole