BIOSYNTHESIS OF OOSPOREIN IN BEAUVERIA BASSIANA (BALS.) VUILL

Abstract

Substrates labeled with carbon-14 were used to investigate the biosynthesis of oosporein in cultures of Beauveria bassiana. Acetate-1-14C and acetate-2-14C were good precursors. Degradation of the pigment by oxidation with chromic acid gave acetic acid which was labeled in the carboxyl and methyl carbon atoms, respectively, with little randomization. It also indicated that six labeled atoms of the first substrate and eight of the second had been incorporated. DL-Mevalonic acid-2-14C, shikimic acid-U-14C, and L-methionine-methyl-14C were not incorporated. Formate-14C was incorporated but did not label the methyl substituents preferentially. Short-term feeding experiments provided evidence that both acetate and malonate units participate in the biosynthesis of oosporein. Orsellinic acid-2-14C, its ethyl ester, and orcinol-3-14C were incorporated into oosporein without randomization of the label.