Abstract
The thiamine requiring strain of E. coli 70-23 showed a maximum growth in the Davis' culture medium with 10^<-10〜-11> mole/tube (final concentration of 2 x 10^<-8〜-9>M) of thiamine, but did not respond well in the medium containing both of pyrimidine and thiazole moieties of thiamine. However, in the existence of 2 x 10^<-5>M pyrimidinyl-nicotinic acid(Pm-NiA)or heteropyrithaimine (HPT), and of 2 x 10^<-4>M pyrimidinyl-cysteine (Pm-CySH) or its sulfoxide (Pm-CySH→O), the bacteria responded well. Pyrithiamine showed an antithiamine activity for growth of the bacteria at the concentration of 2 x 10^<-3>M, but was utilized by the bacteria at 2 x 10^<-4>M. The antithiamine activity was eliminated after preincubation for 48 hours or addition of 2 x 10^<-3〜-7>M thiamine. The existence of thiamine in the harvested bacteria grown in the Davis' culture medium with 2 x 10^<-5>M Pm-NiA was observed by thin layer chromato-graphy. The amount of thiamine was estimated by the microbiological assay with L. fermenti as 0.27 μg/g wet bacteria, which was around 10^<-3> times of concentration to the amount of thiamine in bacteria cultured in medium with 2 x 10^<-5>M thiamine. The mechanism of changes of the thiamine related compounds in the medium into thiamine by the bacteria during cultivation was discussed. (Received May 6,1972)
