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...

Nishida, Shoki (Kanazawa University, Kanazawa, Japan), and Gizo Nakagawara. Relationship between toxigenicity and sporulating potency of Clostridium novyi. J. Bacteriol. 89:993-995. 1965.-The less toxigenic the strains, the stronger was the sporulating potency of Clostridium novyi strains isolated. This was confirmed by investigation of the toxigenicity of substrains of C. novyi 140 possessing ...

Nishida, Shoki (Kanazawa University, Kanazawa, Japan), and Masaaki Imaizumi. Toxigenicity of Clostridium histolyticum. J. Bacteriol. 91:477-483. 1966.-From 234 soil samples, 21 strains of Clostridium histolyticum of different levels of alpha-toxigenicity were isolated by a new method specially designed for the isolation of this species. The alpha-toxigenicity of freshly isolated strains and of ...

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...

clostridium diffcile is part of the normal intestinal flora in a small proportion of healthy persons. when exposed to antibiotics, the normal enteric flora is altered, permitting the overgrowth of these relatively resistant organisms. proliferation of the organisms with localized production of their toxins leads to disease (pseudomembran colitis or antibiotic associated diarrhea). in this study...

Sanada, Ichiro (Kanazawa University, Kanazawa, Japan), and Shoki Nishida. Isolation of Clostridium tetani from soil. J. Bacteriol. 89:626-629. 1965.-The higher the temperatures applied to soil specimens, the weaker the toxigenicity of Clostridium tetani strains isolated from them. The glucose- and maltose-fermenting ability of these isolates was inversely proportional to their toxigenicity. The...

In a previous report (Groman, 1953a) it was concluded that toxigenic Corynebacterium diphtheriae which are recovered following exposure of a nontoxigenic strain to specific bacteriophage result from a direct conversion to toxigenicity' rather than from selection of toxigenic mutants. This conclusion was supported and strengthened by the work of Barksdale and Pappenheimer (1954) in their study o...

Evolutionary theory may contribute to practical solutions for control of disease by identifying interventions that may cause pathogens to evolve to reduced virulence. Theory predicts, for example, that pathogens transmitted by water or arthropod vectors should evolve to relatively high levels of virulence because such pathogens can gain the evolutionary benefits of relatively high levels of hos...

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...