Abstract
The results of chemical investigation of preparations of the group A substance in horse saliva 1 which indicated that their activity may depend upon carbohydrate groupings suggested testing the effect upon the saliva substance, of a microorganism known to attack carbohydrates.
The discovery of a bacterium producing an enzyme which destroys the polysaccharide of Pneumococcus type III was made by Avery and Dubos. 2 Several other bacteria capable of splitting Pneumococcus polysaccharides have been found since by Sickles and Shaw. 3 While the action of the Avery and Dubos bacterium appeared to be specific, a Myxococcus which decomposes a variety of bacterial polysaccharides 4 , 5 was isolated from vegetable matter by Morgan and Thaysen.
The strain of Myxobacterium was sent to us through the kindness of Dr. Morgan. The culture was maintained on an aqueous extract of rabbit feces, 50 gm. to the liter, to which were added 0.05% (NH4)2SO4 and 0.01% K2HPO4. The medium was used at pH 7.4 after Berkefeld filtration or in agar slants. The organism does not grow on most common nutrient media. The substance from horse saliva was dissolved in the fluid medium mentioned or in a simple mineral medium 2 in concentrations of 0.008% to 0.04%, and 3 cc. amounts were inoculated with 0.1 cc. of a 3 or 4 day fluid culture and kept at 37°C. The activity of the saliva preparation was determined by inhibition of the hemolysis of sheep cells by antisera prepared with human A blood.
In these experiments the substance was found to be destroyed during growth of the Myxococcus. Partial decomposition was noted after 2 days, and after a week only 2 to 10% of the original activity remained.
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