Segregation of the ability to degrade lupanine in Pseudomonas lupanini

Two types of mutants differing in the ability to degrade lupanine were obtained from the JD1 strain of Pseudomonas lupanini: lus growing slowly on lupanine, and lun unable to utilize lupanine as a source of carbon and nitrogen. The mutation rate for the spontaneous lus mutants was 0.28%, and for the mitomycin C-induced lus mutants, 3-24%. Rifampicin induced solely lun mutation. The plasmid nature of the lupanine degradation pathway is discussed.