Isolation and characterization of a pigment-deficient mutant of the thermal cyanobacterium Hapalosiphon welwitschii

A pigment-deficient yellow mutant of the thermophilic cyanobacterium Hapalosiphon welwitschii was isolated following exposure to 1 mu g/ml kanamycin. The mutant occurred as a single cell or in a group of two to four thick-walled densely granular spore-like cells. It grew more slowly than the wild type in nitrate. nitrite or ammonium supplemented medium. The mutant was revertible to the wild type following treatment with the mutagenic agent N-methyl-N'nitro-N-nitrosoguanidine.