[Transforming activity of phage T4r+ DNA, treated with ultraviolet light, nitrous acid, hydroxylamine and visible light in the presence of methylene blue].

The efficiency of phages T4rIIB-638v+ and T4rIIB-638v- transformation by native and denatured DNA treated with UV, nitrous acid, hydroxylamine and visible light in the presence of methylene blue is studied. A greater transformation efficiency of UV-irradiated T4r+ phage native and denatured DNA was observed in the v+ recipient as compared with v- recipients. Denatured donor DNA treated with nitrous acid has higher transformation activity in spheroplasts infected with T4v+ phage than in those infected with T4v- phage. Native donor DNA, treated with methylene blue and visible light-irradiated, developed a decrease of the transformation activity in T4v- phage-infected spheroplasts as compared with T4v+ phage-infected spheroplasts. Hydroxylamine treatment of native and denatured donor DNA did not reveal any differences in the transforming activity for v+ and v- recipients. Denatured donor DNA was more resistant to the effect of hydroxylamine than native DNA.