Abstract
Following previous work on the specific carbohydrates of the pneumococcus, a study of preparations from a type-VIII strain has been undertaken in order to determine differences in activity and chemical composition. This culture was isolated in 1930 from pneumonic sputum and has since been maintained at a maximum virulence by frequent mouse passage. It is agglutinated by type-III antiserum in low dilution and by type-VIII in high dilution.
Specific carbohydrate was prepared from the cellular sediment and also from the supernatant fluid of from 16- to 20-hour cultures grown in an infusion-free peptone broth 1 which contained 0.2% cane sugar. The cellular extracts were purified by methods similar to those reported for type-I pneumococcus. 2 The soluble specific substance was best removed from the broth concentrates by precipitation as the barium or calcium salt and by repeated alcoholic precipitations. Purification through the calcium salt resulted in the purest product yet obtained, but the yield was low.
The reactions which distinguished the cellular carbohydrate from the soluble specific substance of the type-I pneumococcus failed to indicate any difference in the type-VIII fractions prepared as described. Although both fractions induced purpura, neither was observed to have immunizing activity in mice; furthermore, precipitation tests with adsorbed sera showed no difference between them.
The type-VIII soluble specific substance was readily soluble in water and gave an acid reaction. It passed through collodion membranes rapidly but through cellophane slowly and only after prolonged dialysis. Analysis of one preparation gave 0.19% nitrogen, 0.06% phosphorus, 0.70% ash, and 3.90% moisture. The specific rotation was about +126°. Before hydrolysis there was no reduction of Fehling's solution, but, when boiled for 4 hours with 10% sulfuric acid, the polysaccharide yielded 69.5% of reducing sugars calculated as dextrose.
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