The role of WaaL ligases of Yersinia enterocolitica O:3 and O:8 in lipopolysaccharide biosynthesis and stress adaptation
Aim. The aim of current studies was to estimate participation of WaaL ligases in lipopolysaccharide (LPS) biosynthesis of Yersinia enterocolitica O:3 and O:8 (YeO3, YeO8) and determine the role of ligases for bacterial growth in conditions of osmotic pressure. Methods. The single and double waaL mutants were created by allelic exchange strategy. Phenotypes of created mutants were visualized by silver-stained DOC-PAGE and immunoblotting with specific OC and O-Ag monoclonal antibodies. The growth media with 3,5% NaCl was used as a sensitivity assay. Results. Deletion of waaLOS gene from YeO3 genome has a marked effect on OC ligation either in single or double mutants. The waaLPS deletion has an opposite effect on the OPS ligation – barely detected increasing of OPS bands. A dramatic decreasing of growth potential in hypertonic medium was observed only in YeO3 double ligase mutant. Conclusions. The importance of WaaL ligase for environmental stress resistance was detected only for YeO3 double mutant. Single ligase gene deletions not affect the osmotic resistance of bacteria, which could be explained as compensation of damaged ligase function by another ligase.
Key words: Yersinia enterocolitica, LPS, WaaL ligases, osmotic pressure.