FIG. 1.

Swimming motility of mini-Mu mutant strains in M agar with tetracycline. All strains were derivatives of strain LM1017. Plates A and B contain the strains indicated in the top row at the left and were incubated at 30°C for 10 and 24 h, respectively. Plates C and D contain the strains indicated in the lower row on the left and were incubated at 30°C for 12 and 24 h, respectively. Strain LM5053 was not inoculated in plates B or D. The control strain LM5053 was tetracycline-resistant and exhibited wild-type motility.