Regulative influence of o-aminobenzoic acid (OABA) on the biosynthesis of nourseothricin in cultures of Streptomyces noursei JA 3890b. V. Effect of OABA on cytochrome levels and amino acid transport.

o-Aminobenzoic acid (OABA) known by its stimulatory effect on streptothricin biosynthesis by Streptomyces noursei JA 3890b was found to suppress specifically the formation of cytochrome a-type terminal oxidase while the levels of the b- and c-type cytochromes apparently remained unaffected. This change was coupled to decreased capacity of transport of u-14C-L-alanine and u-14C-L-glutamic acid into the mycelium, giving rise to delay of amino acid catabolism and decreased production of nitrogen catabolites within the cell. The above results provide supporting evidence for conjectures recently published by us concerning the control by nitrogen catabolites of the secondary metabolism of this strain. As a summary a scheme is proposed showing several hypothetic mechanisms by which nitrogen catabolite regulation of nourseothricin production could be accomplished.