Adaptation of the Propionic-Acid Bacteria to Vitamin B(1) Synthesis Including a Method of Assay.

In a paper dealing with the nutrition of the propionic-acid bacteria Wood, Andersen, and Werkman (1938) report that one species Propionibacterium pentosaceum (49W), can be "trained" to grow as well in the absence of vitamin B1 as in its presence. Their data show that adaptation occurred after continuous serial transfer in an ammonium sulfate medium containing only ether extract of yeast extract as a stimulant; the organism gradually acquired the ability to dispense with vitamin B1. They did not determine whether the organism, "trained" to dispense with the vitamin, acquires the ability to synthesize it, or whether its metabolism is diverted so that the vitamin is no longer required. The present study was undertaken to determine which of the two possibilities occurs. It has been found that the organism acquires the ability to synthesize vitamin B1. A bacteriological method of assay of vitamin B1 employed in the study is also described.