A Note on Conditions affecting the Production of Toxin and Porphyrins by the Diphtheria Bacillus

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Abstract
In cultures, grown in infusion-free peptone medium under varied conditions, and incubated at from 33[degree] to 35[degree]C under ordinary atmospheric conditions, demonstrable amts. of toxin and porphyrins usually appeared within the first 24-48 hrs., increasing up to about the 7th day. No appreciable decrease of either was observed in cultures incubated 3 weeks. Filtrates of cultures in sealed containers in which varying amts. of CO2 or oxygen were present varied in toxicity. Definite absorption bands occupying positions at or near those of the porphyrins were observed for the other extract of every toxic filtrate. However, certain differences in the position of the absorption maxima were noted in the spectra of ether extracts from toxic filtrates of cultures grown under atmospheric conditions, under reduced oxygen tension, and in an atmosphere of CO2. Potent toxins practically free from porphyrins were obtained in a medium containing 1.5% of ash-free charcoal preparation. Porphyrins extracted from a diphtheria toxin and added to medium as a filter-sterilized solution in an amount equivalent to that extracted from an equal volume of toxin did not appear to affect the growth or toxigenic activities of either the toxigenic or nontoxigenic strains tested.

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