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, AND HARLYN 0. HALVORSON. Effect of gene position on the timing of enzyme synthesis in synchronous cultures of yeast. J. Bacteriol. 92:652-661.-In synchronously growing cultures of Saccharomyces cerevisiae, enzyme synthesis is periodic. The effect of various factors on the timing of a-glucosidase synthesis has been investigated. The period of the cell cycle during which ac-glucosidase is synthesized is unaffected by the method employed to induce synchrony, as well as other environmental conditions. However, a definite relationship exists between the number of nonallelic structural genes present for a-glucosidase and the number of periods of synthesis during the cell cycle. It is concluded that the periodic synthesis of enzymes observed in synchronously growing cultures of yeast is probably the result of an ordered process of transcription of the various structural genes.

A mycelial extract of Trichoderma reesei (P-12) was separated into four fractions by high performance liquid chromatography (HPLC). Out of these, two were found to exhibit antifungal activity when tested against plant pathogenic fungi. The level of antifungal compounds was higher in media containing glucose as the carbon source as compared to one containing cellulose. The synthesis of these antifungal compounds started after 3 days of inoculation at 30~ and continued upto 8 days. No further increase was recorded beyond this period.

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