A derivative of Bacillus megaterium QM B1551 cured of all seven resident plasmids was mutated to Lac-. Transposon Tn917 carrying lac2 and cat was then used to isolate four spo: : fucZ-cat fusion mutants by screening for colonies expressing the fusion in stationary phase. The sporulation frequencies of the mutants ranged from lo-' to Macrolide, lincosamide and streptogramin B resistance (MLS') of the mutants cotransduced 100% with the sporulation defect and all four mutations mapped near trp by transduction in the order: trp-hisH-spo. All four mutants isolated were defective early in sporulation since P-galactosidase could be detected between zero and 2 h after the end of exponential growth. Electron microscopy of two of the mutants expressing the enzyme at t,-t2 revealed a defect prior to or just at the beginning of septum formation in one, and after completion of septum formation in the other. Little or no synthesis of dipicolinic acid, glucose dehydrogenase or alkaline phosphatase was detected in the mutants, but each was neutral protease positive. These results show that the mutations were in at least two early genes expressed before glucose dehydrogenase production. This study represents the first genetic characterization of sporulation mutants in B. megaterium and also demonstrates that gene fusion technology can be used in this species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.