[Selective method of isolating mutants sensitive to ultraviolet radiation from a culture of Rhodopseudomonas sphaeroides].

The method of penicillin selection used after UV-irradiation (lambda = 254 nm) allows one to select UV-sensitive mutants (uvs-mutants) of the phototrophous bacterium Rhodopseudomonas sphaeroides induced by nitrosomethylurea with an effectiveness greater by an order of magnitude. Over 30% of the uvs-mutants obtained using this method had an elevated sensitivity not only to far-UV (F-UV, lambda = 254 nm) but also to near-UV (N-UV, lambda greater than 280 nm) UV-irradiation. No correlation was found in the degree of sensitivity to F-UV and N-UV-irradiation of the uvs-mutants. Mutants highly sensitive to the lethal action of N-UV were isolated.