Outer membrane exchange regulates developmental sporulation.

An A+S− strain (DK8615) designated A+ Tra+ was sporulation proficient and arbitrarily set at a 100%; while a nonmotile strain (A− Tra+; DK8601) did not sporulate. The traA::km mutation (Tra−) was crossed into these strains (DW1415 and DW1419, respectively) and their sporulation efficiencies did not significantly change. A-motile and nonmotile strains were then mixed at a 1∶1 ratio and sporulation of the A+ strain was blocked in a Tra+ dependent manner. Development was conducted on TPM starvation agar and cells were harvested after 5 days and viable spores determined in triplicate, averaged and error bars shown.