Ultraviolet inactivation and excision-repair in Bacillus subtilis I. Construction and characterization of a transformable eightfold auxotrophic strain and two ultraviolet-sensitive derivatives

An eightfold auxotrophic strain of Bacillus subtilis was constructed. It was about equally well transformable for all markers. When this strain was used as recipient in transformation, single marker transformation frequencies of 0.5–2.0% were obtained. The markers were located relatively to each other using marker frequency analysis. Two UV-sensitive derivatives, equally well transformable as the parental multiple auxotroph, were isolated. One was highly sensitive to UV irradiation, was host cell reactivation-negative and did not show DNA breakdown or recovery of DNA synthesis after exposure to UV. Using UV-inactivated transforming DNA, this strain's transformability was strongly reduced as compared with both the UV-resistant parental strain and the other, moderately UV-sensitive, strain.