Wax Ester and Triacylglycerol Production in : Role in Osmostress Protection, Reactive Oxygen Species, and Antibiotic Sensitivity.

Wax esters (WEs) are neutral lipids that are produced by many different bacteria as potential carbon and energy storage compounds. Comparatively little is known about the role of WE in pathogenic bacteria. The opportunistic pathogen is a major cause of hospital-acquired infections worldwide. Salt and desiccation resistance foster infections such as urinary tract infections and allow for reinfection when bacteria are taken up from dry surfaces in the hospital environment. Here we report on WE and triacylglycerol (TAG) production in as a response to nitrogen limitation and high salt stress. Fatty acids and fatty alcohols with chain lengths of C and C were identified as the most prominent WE constituents. We identified the terminal key enzyme of WE biosynthesis, the bifunctional wax ester synthase/acylCoA:diacylglycerol acyltransferase (WS/DGAT) encoded by the gene, and demonstrated that transcription of and production of WS/DGAT are independent of the nitrogen concentration. A mutant was impaired in growth in the presence of high salt concentration and was more sensitive to imipenem and reactive oxygen species.