[Isolation and characterization of Proteus mirabilis mutants deficient in DNA degradation: function of endonuclease I in postmortem DNA degradation].

DNase deficient mutants of Proteus mirabilis selected for reduced toluene induced DNA degradation were isolated. Their defect in DNA degradation was shown not only after treatment by toluene but also in crude extracts after cell disintegration by ultrasonic and in untreated starved cultures. The degradation mutants behave just as the wild type with respect ot their in vivo functions proffed. The results inidcate that the affected DNase does not have an essential function in vivo but acts in postmortem DNA degradation. Probably the DNase in question concerns the endonuclease I of P. mirabilis described by Goebel and Helinski (1971 a, b).