Large-scale isolation and partial characterization of plasmid DNA from B. larvae.

Large-scale preparation of plasmid DNA from two Bacillus larvae strains 423 and 728, honey-bee pathogens, is described. The isolated plasmid DNAs were analyzed by restriction enzyme mapping. No difference in the resulting maps was found for six restriction enzymes. The plasmid DNAs were also compared by Southern blot hybridization and by electron microscopy. The results confirmed the identity of these plasmid DNAs. All these data suggest that B. larvae strains harbor the same plasmid.