FIG. 2.

(A) TEM of an A. hydrophila AH-3 defined mutant in pomB₂ (AH-4470) grown at 25°C on liquid medium (1) and grown at 25°C on swarm agar (2). Bacteria were gently placed onto Fonvard-coated copper grids and negatively stained using 2% uranyl acetate. Bar, 1 μm. (B) Swarming motility observed for A. hydrophila AH-3 (1), pomB₂ mutant AH-4470 (2), pomB-pomB₂ double mutant AH-4472 (3), and double mutant AH-4472 complemented with plasmid pACYC-POMAB (4a) or pACYC-POMA₂B₂ (4b) independently. The pomA₂B₂ double mutant AH-4471 shows the same TEM result and swarming phenotype as pomB₂ mutant AH-4470. The double mutants AH-4473 (pomAB-A₂B₂) and AH-4452 (pomAB-B₂) show the same swarming phenotype as the AH-4472 mutant (pomB-B₂).