Accumulation of α-Alanine and of Pyruvate in Diphtherial Culture Filtrate and its Relation to Iron Deficiency of Medium

IT was shown by Linggood and Woiwod¹ that marked changes, particularly an increase in the quantity of α-alanine, occurred in the chromatograms of a casein hydrolysate medium before and after the growth of a strain of C. diphtheriae under conditions favourable for toxin production. While studying the effect of iron on the amino-acid metabolism of a strain of C. diphtheriae in a simplified, chemically defined medium developed in our laboratory^2,3, we have also found that several amino-acids, especially α-alanine, appear and accumulate in the culture filtrate when the medium is deficient in iron. In further experiments, it has also been demonstrated that an accumulation of pyruvate takes place under the same conditions, and that the amounts of α-alanine and pyruvate appearing in the filtrates, decrease with the increasing iron content of the medium.