Polyphosphate-deficient mutants of Anacystis nidulans

Polyphosphate-deficient mutants of Anacystis nidulans have been isolated by either ethyl methanesulfonate (EMS) or N-methyl nitrosoguanidine (NTG) mutagenesis and penicillin-enrichment techniques. Mutagenised stock was preincubated in a medium lacking sulfate, then transferred to a phosphate-lacking medium before penicillin treatment. Many single-colony isolates, in contrast to wild-type, show little growth in absence of phosphate, and have altered polyphosphate, and have altered polyphosphate kinase levels indicating that the lesions affect either the activity or the expression of this enzyme. In these same mutants radioactive phosphate incorporation is severely retarded. Electron micrographs confirm the absence of polyphosphate granules in some mutants.