The Influence of Certain Derivatives of Vitamin B12 upon the Groth of Micro-Organisms

Abstract

SUMMARY: Seven analogues of vitamin B₁₂ were examined for their influence upon the growth of Ochromonas malhamensis, Euglena gracilis, Lactobacillus leichmannii ATCC 4797 and Escherichia coli 113–3. The analogues were active in promoting the growth of E. gracilis and L. leichmannii, but were essentially inactive for O. malhamensis. For E. coli three of the analogues were active and four inactive. In O. malhamensis and in E. coli, the ‘inactive’ analogues antagonized the growth-promoting action of cyanocobalamin, apparently by saturating the cells’ mechanism for ‘binding’ the vitamin and so preventing its uptake.