Temperature-sensitive mutants of Mycoplasma gallisepticum

Mycoplasma gallisepticum (MG) S6 strain was treated with nitrosoguanidine to obtain temperature-sensitive mutants. Of the 101 colonies screened, 4 were found to be temperature sensitive. These mutants and the wild type organisms were serologically and morphologically identical. Three of the 4 mutants failed to produce air sac lesions when inoculated directly into air sacs of the chicken.