STUDIES ON THE AEROBIC MESOPHILIC BACTERIA WITH DISTICTLY BULGED SPORANGIUM : Ⅰ. NUTRITIONAL REQUIREMENTS OF BACILLUS THIAMINOLYTICUS

B. thiaminolyticus and B.alvei grow well in a synthetic medium containing 17 amino acids, glucoce and salts. Among strains teated it could be observed that there were different amino acids requirement depending on the variety of strains belonging to the same species, but that the indispensable amino acids for all strains of B.thiaminolyicus tested were leucine, isoleucine, proline and asparagine and for those of B.alvei isoleucine, valine, tryptophan and methiomine.　A amall amount of glucose stimulated the growth both species in synthetic medium, but 0.5 to 1.0 per cent of the sugar inhibited the growth of B. thiaminolyticus but not that of B. alvie. Thiamin alone inhibits the growth of B. thiaminolyticus, but in the presence of vitamin mixture the growth may be initiated late and finally reaches to a level comparable to that of growth in the medium which contains pyeimidine and thiazole moieties of thiamin and vitamin mixture. This medium permits the best growth to B.thiaminolyticus of may media tested. These observations indicate that thiamin is inhibitory for the bacterial growth and that after initiation of growth, thiamin breaksdown and the resulting products promote growth. The inhibitory effect of ”Oxythiamin”, may be due to the inability of the thiaminase to attack this anti-thiamin. The inhibitory effect of amino-thiazole indicates that thiazole plays an important role in the metabolism of B. thiaminolyticus. ”Heteropyrithiamin” was found by Fujita et al.10) to be produced from thiamin and pyridine by the enzymatic activity of thiaminase, and pyrimidyl compounds analogous with the ”Heterpyrithiamin” wrer considered by them to be produced from thiamin in matural conditions without pyridine. The fact that the ”Heteropyrithiamin” promotes the growth of the organisms, suggests that the enzyme products in natural conditions may have favorable effects on the growth of B. thiaminolyticus. The author demonstrated that an unknown substance by means of shaking withconcenteated sodium hydroxide, was produced by B. thiaminolyticus. Therefore, thiamin in the cultures of the B. thiaminolyticus must be assayed after this mialeading substance has been removed by preliminaty butanol extraction.