Ether-soluble "oils" of specific gravity > 1 were produced extracellularly in yields of over 16 gm./liter fermentation mixture by strains of Ustilago zeae growing in shaken flasks on medium containing cerelose, urea, and sugar beet molasses. The bulk of the oily material was shown to be a glycoside of mannose and erythritol, and in addition, itaconic acid and dianthrone were shown to be present. Yields of itaconic acid as determined by a bromine–iodine method at pH 1.2 (Friedkin) reached values of over 15 gm./liter but such values were considerably higher than those indicated by quantitative isolation of this acid. One hundred and eighty isolates of Ustilago were grown on medium with and without calcium carbonate and some 45 isolates produced extracellular oily material, 98 produced ustilagic acid, and 50 produced both crystals and oil. Ether-soluble substances from freeze-dried fermentation mixtures of different isolates ranged from 1 to 12 gm./liter, while methanol-soluble substances from ether-extracted freeze-dried fermentation mixtures ranged from 1 to 45 gm./liter.

No abstract

The fatty acid compositions of the mycelia of a parasitic species of Pythium and of various hosts are reported. The Pythium spp. contained high concentrations of myristic acid and low concentrations of linoleic and linolenic acids in comparison with concentrations in other fungi tested. Appreciable amounts of unsaturated C20 acids, uncommon in fungi, were found in the Phycomycetes tested. Vegetable oils and other fats of widely varying fatty acid compositions were all effective in stimulating sexual reproduction of the Pythium sp. It was concluded that substance(s) other than fatty acids present in the vegetable oils were responsible for the stimulation observed. The most active fraction in sunflower seed oil was isolated and identified as a phytosterol, probably β-sitosterol. The results of testing for stimulatory activity a series of structurally related compounds indicated that the sexual reproduction of the Pythium sp. studied required the presence of a substance such as β-sitosterol or cholesterol or one with similar structure and which similarly satisfied certain specific structural requirements regarding length of the C17 side chain, stereochemistry, and position of the oxygenated function. β-Sitosterol and cholesterol were effective at 0.2 γ/ml in potato dextrose agar.

No abstract

The antibiotic activity of Ustilago zeae (PRL 119) cultures is associated mainly with the culture solids and it has been shown that a mixture of glucolipids, called ustilagic acid and produced in good yields by the fungus, is responsible for part, if not all, of the observed activity. The antibiotic activity of ustilagic acid corresponds to that originally attributed to ustizeain B and therefore these two are considered to be identical. All samples of ustilagic acid obtained showed antibiotic activity and it has not been possible by paper chromatography to separate an active principle from the acid. Recrystallization of ustilagic acid did not alter its antibiotic properties. Alkaline hydrolysis of the acid destroyed its activity. Heating the culture mixture for up to an hour at temperatures less than 100° C. did not alter materially the antibiotic properties of the mixture or of the acid extracted therefrom. The antifungal spectrum is broad and the antibacterial spectrum includes more Gram-positive than Gram-negative organisms. Preliminary tests with rats indicated that ustilagic acid is nontoxic when administered orally up to at least 5% of the diet, and with mice, orally up to at least 1% of the diet or intraperitoneally in amounts up to 1.5 gm. per kgm. of body weight.