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Staphylococcus enterotoxin Mehling, Agnes E.

Abstract

The constituents of a synthetic medium and the conditions required by staphylococcus strain 12069 alpha for good toxin production have been determined. Because essentially all the components of the medium are dialyzable, dialysis for 24 hours was found to produce an average reduction of 98.34 per cent of the solids, but an average reduction of 53 per cent of the potency. Various methods of concentrating the toxin were studied. Vacuum distillation experiments indicated an almost complete loss of potency. "Desi-vac" treatment produced a loss of approximately 50 per cent, and a product which varied in weight content, stability, toxicity, and response to purification. Lyophilization produced a loss of approximately 20 per cent, and a product which reacted more consistently to further treatment. The freezing method of concentration was shown to be applicable to the problem. The concentrated toxic filtrates were subjected to additional purification procedures. The toxin was adsorbed from solution by "Norit", but its elution was not achieved. Ethanol, methanol, and acetone precipitation experiments were performed, but only the methanol treatment showed any evidence that would warrant further investigation Cadmium chloride precipitation removed the active component from filtrates, but residual cadmium proved too toxic in animal tests to permit the degree of separation of enterotoxin to be determined. The probable polysaccharide nature of enterotoxin was demonstrated by enzyme experiments upon crude toxic filtrates, but further study was prevented because of the extremely small yields of relatively purified material. Enterotoxin purified by acid precipitation at pH 3.5 gave a negative Biuret and a positive Molisch reaction. The low antigenic power demonstrated by the relatively pure filtrates was also indicative of the non-protein nature of the toxin. The acid precipitation at pH 3.5 of dialyzed and concentrated filtrates produced a material whose soluble fraction was found to have an average weight of 150 gamma per cat test dose, and a nitrogen content of less than 2 per cent. The recovery of enterotoxic potency in material treated by dialysis, concentration, and precipitation, averaged 7.33 per cent of the original.

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