Relationship of Growth-Phase to the Reducing Activity of Bacterial Cells

Abstract

IN the course of an investigation¹ on the reduction of formaldehyde by a strain of Pseudomonas æruginosa, it was demonstrated that treatment of the bacteria with single amino-acids that were able to support adequately their growth in culture media, prior to the addition of formaldehyde, considerably enhanced the subsequent rate of uptake of the latter compound by the organism. This rise in reducing activity was assumed to be related to processes preparatory to cell multiplication. Pollock and Wainwright² found that the nitratase activity of washed suspensions of the coliform organism ‘1433’ was markedly stimulated in the presence of tryptic meat broth or a mixture of eighteen amino-acids. They suggested that, in accordance with Spiegelman and Dunn's theory³, the external supply of nitrogen would serve as a source for the synthesis of more enzyme protein.