Blocking Phosphatidylcholine Utilization in Pseudomonas aeruginosa, via Mutagenesis of Fatty Acid, Glycerol and Choline Degradation Pathways, Confirms the Importance of This Nutrient Source In Vivo

摘要: Pseudomonas aeruginosa can grow to very high-cell-density (HCD) during infection of the cystic fibrosis (CF) lung. Phosphatidylcholine (PC), major component lung surfactant, has been hypothesized support HCD growth P. in vivo. The phosphorylcholine headgroup, a glycerol molecule, and two long-chain fatty acids (FAs) are released by enzymatic cleavage PC bacterial phospholipase C lipases. Three different pathways, choline, glycerol, acid degradation then involved these components. Here, we identified five potential FA (Fad) related fadBA-operons (fadBA1-5, each encoding 3-hydroxyacyl-CoA dehydrogenase acyl-CoA thiolase). Through mutagenesis analyses, showed that three (fadBA145) dominant medium-chain Fad. triple fadBA145 mutant also reduced ability degrade vitro. We have previously shown partially blocking Fad, via fadBA5 fadDs, could significantly reduce replicate on vitro, as well mouse However, no studies assessed mutants, defective choline and/or conjunction with or Hence, constructed additional mutants (ΔfadBA145ΔglpD, ΔfadBA145ΔbetAB, ΔfadBA145ΔbetABΔglpD) FA, and, therefore, PC. analysis BALB/c model significant inability utilize resulted decreased replication fitness competitiveness vivo compared complement strain, although there was little variation typical virulence factor production (e.g., hemolysin, lipase, protease levels). This further supports hypothesis surfactant serves an important nutrient for CF infection.