Abstract
The growth of Lactobacillus fermenti was competitively inhibited by antithiamine compounds ; imidazolothiamine (I), benzylimidazolothiamine (II), butylimidazolothiamine (III) and triazinothiamine (IV) (Vitamins 32,383,1965 ; 33,488,1966 ; 34,289,375,1966). Thiamine uptake of Lactobacilli cells was inhibited by these compounds in the following order of inhibition : pyrithiamine > I ≒ II ≒ III > IV. Correlation between the growth-inhibition indices of the compounds and the uptake of thiamine by the cells in the presence of the compounds was shown in Fig. 1. The stronger inhibition to the growth of L. fermenti in the broth containing thiamine diphosphate than in the broth containing thiamine was shown by all the compounds. The stronger inhibition to cell-uptake of thiamine diphosphate than that of thiamine by the compounds was also demonstrated.
