CORRELATION BETWEEN GENETIC TRANSFORMABILITY AND NON-PHOTOREACTIVABILITY IN BACILLUS SUBTILIS.

Kelner, Albert (Brandeis University, Waltham, Mass.). Correlation between genetic transformability and nonphotoreactivability in Bacillus subtilis. J. Bacteriol. 87:1295-1303. 1964.-Photoreactivation after ultraviolet irradiation was studied in the transformable Bacillus subtilis SB-1. Moderate photoreactivability (maximal increase in survival due to photoreactivating light, five- to tenfold) was found in (i) noncompetent vegatative cells produced in Brain Heart Infusion broth, and in (ii) the total viable cells of a competent culture grown in special competency-producing medium and tested either just before or after transformation with deoxyribonucleic acid. However, no, or only trace, photoreactivation (maximal increase in survival, 1.5- to 2-fold) was found in that fraction of a competent culture actually able to be transformed. This nonphotoreactivability was a temporary property of transformable cells, since clones derived from them were normally photoreactivable. Nonphotoreactivability is not explained by injury to transformants caused by photoreactivating light, although transformants are killed by very large doses of light. The findings in B. subtilis strengthen the idea that transformability is generally correlated with nonphotoreactivability.