Genetic Analysis of Fusion Recombinants and Presence of Noncomplementing Diploids in Bacillus megaterium

Publisher Website
Google Scholar
Abstract
Genetic analysis in B. megaterium was done using the technique of protoplast fusion that was previously successfully applied in Staphylococcus and Streptomyces. Efficient production of protoplasts, fusion and regeneration techniques were established. Variability in numbers and types of recombinants using 2, 3- and 4-factor crosses was observed throughout these studies. No linkages were detected, even between loci known to be linked by cotransduction with bacteriophage MP13. These results were similar to those reported by Alfoldi et. al. using B. megaterium strain 216, even though the experimental design was significantly changed. During initial subculturing, segregants were observed in a 1:2:2 ratio of noncomplementing diploids:parental-1:parental-2. The ratio changed dramatically after 7 subcultures. Double recombinants appeared after 9 subcultures. These results corroborate those reported in B. subtilis and suggest that there is a locus-inactivation phenomenon present in Bacillus which is not evident in Streptomyces or Staphylococcus. Until the mechanism is elucidated, protoplast fusion should not be used for chromosomal mapping in B. megaterium. However, it can be used to transfer plasmids among the bacilli at a frequency of 10-5-10-6 per regenerated protoplast.

This publication has 21 references indexed in Scilit: