Susceptibility to SP-A-Mediated Membrane Permeabilization Is Dependent on Intact Flagellum Structure but Independent of Flagellar-Mediated Swimming Motility.

<p>(A) Wild-type <i>P. aeruginosa</i> strain PA14 and its isogenic derivative δ<i>motAB</i>, δ<i>motCD</i> and δ<i>motAB</i>, δ<i>motCD</i> were tested for swimming motility and susceptibility to SP-A-mediate membrane permeabilization. Mutant strains δ<i>motAB</i> and δ<i>motCD</i> were motile, but δ<i>motAB</i>, δ<i>motCD</i> was nonmotile on swimming motility agar plate. (B) All δ<i>motAB</i>, δ<i>motCD</i> and δ<i>motAB</i>, δ<i>motCD</i> mutant strains were resistant to SP-A-mediated membrane permeabilization, indicating that susceptibility to SP-A is independent of flagellar-mediated motility. (C) The <i>flgK</i> mutant, which could not assemble flagellum, was nonmotile. (D) The <i>flgK</i> mutant was susceptible to SP-A-mediated membrane permeabilization. Data were the mean±SE, <i>n</i> = 8 for each bacterial strain. The difference in membrane permeabilization between <i>flgK</i> and PA14 was significant from 31^st-min onward. *<i>p</i><0.05.