Myrtle Shaw

Cultivation of Coxsackie Virus in Embryonated Eggs and in Chick Tissue Cultures

Summary Among 29 strains of Coxsackie virus tested in embryonated eggs, one strain, serologically Group A, Type 2, exhibited unusual pathogenicity for chick embryos. Of 16 strains tested, the same strain, 3 other Type 2 strains, and a Group A, Type 4 strain grew readily in vitro on embryo chick tissue. These results suggest that strain differences are a primary factor in adaptation to growth in embryonated eggs or tissue culture.

Serologic Studies of Theiler's Mouse Encephalomyelitis Virus

Summary Satisfactory antisera to various Theiler strains were prepared in hamsters. Using Theiler-free suckling mice in neutralization tests, reciprocal cross reactions between GD VII and TO strains were demonstrated. Serologic differences within the TO group were also noted, the titer of a serum being in each case higher for the homologous than the heterologous strains.

A Microörganism which Decomposes the Specific Carbohydrate of Pneumococcus Type VIII

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

Action of Microorganisms from Soil on Type-Specific and Nontype-Specific Pneumococcus Type-I Carbohydrates

The report of Avery and Dubos 1 that the specific carbohydrate of pneumococcus type III was split by an enzyme from a soil microorganism appeared to offer a new approach to the study of relationships and differences between chemically and immunologically different preparations of the specific carbohydrates. Organisms which decompose the specific carbohydrates of pneumococcus types II and III were described in a previous report. 2 We now have in pure culture a microorganism which utilizes to some extent the specific carbohydrate of pneumococcus type I. As in the study of the bacteria that decomposed the carbohydrates of pneumococcus types II and III, the precipitation test with antipneumococcus serum was used as an indication of the presence or absence of the carbohydrate, but, unlike the results obtained with these microorganisms, the precipitation reaction never entirely disappeared. It has not yet been ascertained whether this residual reaction is due to an unused portion of the original carbohydrate or to products of decomposition, which might either be present in the original sample or be formed as a result of the action of the microorganism from the soil. In mixed culture, as it was first obtained from soil, this microorganism could not be cultivated on the purified specific carbohydrate, and, until it was isolated in pure culture, it had to be maintained on a mineral medium to which specific carbohydrate only partly purified had been added. In pure culture, the microorganism utilized the soluble specific substance obtained from broth culture and the specific carbohydrate isolated from pneumococcus type-I cells as well.

Cultivation of Egg-Adapted Theiler's Mouse Encephalomyelitis (TO) Virus in Chick Tissue Culture

Summary 1. An egg-adapted strain of Theilers mouse encephalomyelitis virus (TO) has been carried through 42 passages in vitro on embryonic chick tissue. Attempts to adapt the mouse passage virus directly to chick tissue culture were unsuccessful. Preliminary growth in embryonated eggs, followed by tests in mice of 20% embryo suspensions, facilitated the titration of tissue culture fluids. 2. One of 3 strains of approximately the same mouse-infective titer failed to adapt either to egg or tissue culture. 3. A representative strain of Theilers mouse encephalomyelitis (TO) virus obtained from the American Type Culture Collection also adapted to egg and tissue cultivation.