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The uptake of various 14C labelled compounds like (1-14C) glucose, (1-14C) acetate, (2-14C) uracil, (1-14C) leucine and (14C-CH3) methionine was studied in Aspergillus parasiticus. A comparative study of asparagine deficient, zinc deficient and SLS cultures revealed different growth patterns. High lipid levels under zinc and asparagine deficiency were observed. During the stationary phase the synthesis of proteins and DNA declined. The uptake of 14C labelled glucose, methionine and acetate was maximum in asparagine deficient cultures during the transitional and stationary phase of growth. Maximum uptake of labelled methionine and glucose occured during the exponential growth phase (45 h). The uptake of labelled leucine was highest under asparagine deficiency during the exponential and transitional phases but reached a minimum during stationary phase. The uptake of labelled uracil remained high throughout in the asparagine deficient cultures. The mechanism of inhibition of aflatoxin biosynthesis in the absence of zinc and asparagine seems to be different.

The effect of lithium on growth and aflatoxin production in chemically defined medium was studied on three aflatoxigenic strains of Asperigillus flavus group. The three strains used differed in their aflatoxin producing capacities. The possible mechanism of lithium induced stimulation of aflatoxin biosynthesis is discussed.

Wachsester vol nAspergillus flavus enthalten Palmitinsäure, Ölsäure und Oleylalkohole als Hauptkomponenten. Das Maximum der Aufnahme von markiertem (1—14C)-acetat in Wachsester wurde vom 2. Tage ab des Wachstums beobachtet (ungefähr 19%), während der Einbau in die Aflatoxine vom 10. Tage ab beobachtet wurde, wenn der Einbau in die Wachsester beträchtlich abnimmt. Die Wachsesterhydrolysate enthalten Vorstufen von Aflatoxin B1. Ein Neuntel der Radioaktivität des Aflatoxins ist auf die Ölsäure zurückzuführen. Es wird daher postuliert, daß der Pilz die Wachsester in die Aflatoxine metaboliert.

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Some biochemical properties ofTrigonella foenum-groecuminfected withPeronospora trifoliorumhave been investigated. Qualitative changes were observed in lipids, coumarins, amino acids and indole compounds only. A quantitative study of the phosphate content was also carried out. Neutral lipids did not show any significant changes. In addition to the fourteen phospholipid bands, the infected leaves contained a new band corresponding in Rfto phosphatidic acid or polyglycerophosphate. Seven coumarins were present in both the extracts. In addition 3-hydroxy coumarin, 5-hydroxy-4-methylcoumarin and 7-hydroxy-4-methyl-coumarin were detected in infected leaves. Higher levels of indole acetic acid and three of its derivatives were observed due to infection. Infection altered the free amino acid content. Tryptophan appeared and the total phosphate content increased. Increase in phenols and indoles suggest a higher respiratory rate whereas a higher content of inorganic phosphate suggests uncoupling of phosphorylation from respiration.