MINIMAL BROTH, DAVIS

Nutritional mutants of Escherichia coli obtained by the exposure of wild type E. coli to ultra violet light need a nutritionally complete medium to grow. Minimal media can be supplemented with the desired additives to study nutritional characters of the nutritional mutants. Minimal media are the formulations of Davis as described by Lederberg. Minimal media contain the necessary nutrients only for the growth of wild type E. coli strains. By the random isolation method described by Lederberg, nutritional mutants derived from irradiated cultures of wild type E. coli can be isolated. These mutants can also be isolated by the use of penicillin as described by Davis and Lederberg. Bacillus subtilis mutants can be isolated by these techniques and by the penicillin technique also, as described by Nester et al.

for isolation and characterization of nutritional mutants of Escherichia coli