Abstract
From samples of uncultivated soil obtained in several localities, a microörganism has been isolated in pure culture, by methods previously described, 1 which decomposes the specific carbohydrate of pneumococcus type VIII. Although marked cross precipitation is obtained with pneumococcus type-VIII specific carbohydrate in type-III antiserum 2 and, conversely, with type-III carbohydrate in type-VIII antiserum, strains of soil bacteria (B. palustris) 1 which decompose the carbohydrate of pneumococcus type III do not act on that of type VIII.
The two microörganisms correspond closely in morphology, cultural characters, and in the production of a soluble enzyme; and the new culture should also be classified as B. palustris. The vegetative cells are Gram-negative motile rods with peritrichal flagella, usually 6 in number. They vary in width from 0.6 to 0.8μ and in length from 2.5 to 3μ. Oval spores wider than the vegetative cells are formed. Colonies on blood agar are from 1 to 2 mm. in diameter, smooth, moist with somewhat raised crenated edges. The colonies are of 2 types—one, white and opaque; the other, gray and semitranslucent.
Other cultural characters are also very similar to those displayed by the microörganism which utilizes the carbohydrate of pneumococcus type III. Growth was obtained in mineral medium containing 1% of dextrose, saccharose, maltose, dextrin, salicin, xylose, and galactose, but change in the reaction of the medium was negligible. No growth was present in mineral medium containing lactose, inulin, and mannite. The optimal temperature for growth appeared to be about 29°C, but it took place up to 40°C. Maximum growth and enzyme action were obtained at from pH 7.0 to 7.5, although both were present over a wide range. It was possible to concentrate the soluble enzyme by ultrafiltration through a 9 1/2% acetic-acid nitrocellulose membrane. 3
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