SITE OF BIOSYNTHESES OF SULFUR COMPOUNDS IN GROWING COLONIES OF ASPERGILLUS NIGER

Abstract

The mycelial mat of Asperillus niger grown for 60hr on the cellophane-agar was briefly labeled with ³⁵S-sulfate, and the change in specific activities of choline sulfate and sulfur-protein contained in the mat was followed during the course of its cultivation on the "cold" medium.
From the characteristic pattern of the change in the specific activities, it was inferred that the biosyntheses of these S-compounds take place on, at least, two sites in the upper and lower layers of the mycelial mat.
Proteins obtained from the upper layer was found to be richer in cyst(e)ine content than that from the lower layer. The cellular differentation of mold colonies during sporulation was discussed with reference to the specific nature of the chemical composition of conidia.