FACTORS AFFECTING YIELDS OF ALPHA-HORMONES OF PHYTOPHTHORA-PARASITICAOBTAINED BY ADSORPTION

The conditions for improved yields of the alpha hormones of Phytophtho ra parasitica compared with those of the original technique establishe d by Ko are described. Both hormones alpha 1 and alpha 2 were adsorbed on the Millipore filter by exposing both sides of the filter directly to freshly inoculated 40% V-8 agar blocks for 4 days. Usage of polyca rbonate membrane in the original method to maintain sterility of the f ilter was replaced by sterilization of the filter with ethanol. Among five organic solvents tested, 95% ethanol was the most effective in ex tracting both alpha hormones from the Millipore filter. A 1-min shakin g of the hormone-loaded filter with 95% ethanol was sufficient to extr act ca. 95% of hormones alpha 1 and alpha 2. Results on the solubility properties suggest that the alpha hormones of Phytophthora parasitica are lipid-like natural products and that hormone alpha 2 is more pola r than hormone alpha 1.