Fig 5.

Mutants of lipid transport proteins MlaA and MlaZ or the lipase MlaY fail to degrade cardiolipin upon treatment with sphingosine and are relatively resistant to sphingosine. (A) To determine cardiolipin, the P. aeruginosa MlaA and MlaZ mutants, which are mutants of the lipid transport machinery for phospholipids, and the MlaY mutant, which functions as a lipase, and the corresponding wild-type strain were incubated with 1, 5, or 10 µM sphingosine for 15 min or left untreated; the bacteria were pelleted and extracted; and cardiolipin was determined as above. Mean ± SD, n = 5, ^***P <0.001, ANOVA, and post hoc Tukey test. (B) 10,000 CFU of the above-described bacterial P. aeruginosa strains were incubated with 1, 5, or 10 µM sphingosine for 45 min or left untreated, and CFU were counted after o/n culture on agar plates. Given are the mean ± SD of five independent experiments; ^***P <0.001, ANOVA, post hoc Tukey test.