Phosphatidylcholine (PC) is a ubiquitous membrane lipid in eukaryotes but has been found in only a limited number of prokaryotes. Both eukaryotes and prokaryotes synthesize PC by methylating phosphatidylethanolamine (PE) by use of a phospholipid methyltransferase (Pmt). Eukaryotes can synthesize PC by the activation of choline to form choline phosphate and then CDP-choline. The CDP-choline then...

Polymyxins are often the only option to treat acquired multidrug-resistant Pseudomonas aeruginosa. Polymyxin susceptibility in P. aeruginosa PAO1 is associated with the lipopolysaccharide structure that is determined by arnBCADTEF and modulated by phoPQ and pmrAB. We examined five clonally unrelated clinical isolates of polymyxin B-resistant P. aeruginosa to investigate the molecular basis of p...

SUMMARY Pseudomonas aeruginosa PAO1 was recently reported to exhibit an unusual property of dramatically reducing the efficiency of oxygen transfer from the gas phase into the liquid phase and thus causing oxygen limitation in the culture. In this work, we show that iron concentration in the culture plays a crucial role in evoking this phenomenon. The physiological responses of two P. aeruginos...

Bacterial persister cells are highly tolerant to antibiotics and cause chronic infections. However, little is known about the interaction between host immune systems with this subpopulation of metabolically inactive cells, and direct effects of host immune factors (in the absence of immune cells) on persister cells have not been studied. Here we report that human granulocyte macrophage-colony s...

The expression of many virulence factors in Pseudomonas aeruginosa is dependent upon environmental conditions, including iron levels, oxygen, temperature, and osmolarity. The virulence of P. aeruginosa PAO1 is influenced by the iron- and oxygen-regulated gene encoding the alternative sigma factor PvdS, which is regulated through the ferric uptake regulator (Fur). We observed that overexpression...

Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identi...

Plasmids encoding mercury resistance carried by Pseudomonas aeruginosa PAO1161 and PA103 were found to be involved in regulating the secretion of protease, phospholipase C, and alkaline phosphatase. Previously, mutations in Pseudomonas strains that caused pleiotropic effects on the production of extracellular enzymes were mapped to the bacterial chromosome. We show that pleiotropic changes in e...