Rapid determination of Corynebacterium diphtheriae toxigenicity by counterimmunoelectrophoresis.

Genetic Factors in Corynebacterium Diphtheriae Conversion1

The conversion to toxigenicity of nontoxigenic Corynebacterium diphtheriae strain C4 requires the active and continued participation of a specific bacteriophage (Groman, 1953, 1955). The facts supporting this statement are: (1) lysogenization with 3 phage results in a simultaneous change to toxigenicity, and (2) reversion of toxngemnc cells to the nonlysogenic state results in a return to the n...

A modified toxigenicity test for Corynebacterium diphtheriae.

Determination of Corynebacterium diphtheriae toxigenicity by a colorimetric tissue culture assay.

Chinese hamster ovary (CHO) cell cultures in microtiter wells are sensitive to growth inhibition and killing by picogram quantities of diphtheria toxin. In the absence of biologically active toxin, the CHO cell culture produces sufficient acidic metabolites to change the phenol red pH indicator from pink to yellow within 56 h. In the presence of 10 pg of toxin per well, growth inhibition can be...

Tissue culture method for toxigenicity testing of Corynebacterium diphtheriae.

A method for toxigenicity testing of Corynebacterium diphtheriae in tissue cultures was developed. Results were obtained by comparing destruction of the monkey kidney or, preferably, rabbit kidney monolayer by 0.1 ml of the C. diphtheriae culture in Elek's broth containing 20% rabbit serum with the appearance after the addition of 0.2 ml of a mixture of the C. diphtheriae culture and diphtheria...

Evidence for the induced nature of the change from nontoxigenicity to toxigenicity in Corynebacterium diphtheriae as a result of exposure to specific bacteriophage.

It was reported by Freeman (1951) and Freeman and Morse (1952) that exposure of certain nontoiigenic strains of Corynebacterium diphtheriae to specific bacteriophage resulted in the appearance of toxigenic C. diphtheriae which were resistant to the bacteriophage. It was established further by Freeman (1951) that all toxigenic cells isolated from the resistant growth were lysogenic, carrying a p...