[The influence of the antivitamine pyrithiamine on the metabolism of the thiamin-autotrophic Serratia marcescens].

A new method is described for the quantitative microbiological analysis of the thiamine analog pyrithiamine present in biological material. The method uses a mutant of Lactobacillus fermenti (ATCC 9338) stimulated by pyrithiamine. By this specific method it is found that Serratia marcescens is able to consume and to phosphorylate the antivitamine (presumably to pyrithiamine monophosphate). The uptake of the analog influences neither the generation time of Serratia marcescens nor the biomass of the culture, nor the total amounts of carbohydrate and protein within the cells. On the contrary, pyrithiamin stimulates the exponential death-rate k and decreases the quantity of neutral fats. The carbon source glycerol is consumed at a higher rate, which is paralleled by an increased total amount of pyruvate as well as by an increased biosynthesis of acetoin.