Biological functions of arlS gene of two-component signal transduction system in Staphylococcus epidermidis
Objective To investigate biological functions of arlS gene deletion which encodes a histidine kinase and is located in the arlS/R two-component signal transduction system of S. epidermidis. Methods A plasmid pBT2-△arlS was constructed with inserting erythromycin resistance gene (ermB). Then S. epidermidis 1457 transformed with pBT2-AarlS by electroporation was continuously subcultured at 43℃until arlS deletion strain (SE1457-△arlS) was selected by homologous recombination. Effect of the arlS mutant on biofilm formation was examined by a semi-quantitative microtiter plate assay. Bacterial growth curve was determined by measuring the value of A595. The bacteriolytic activities of supematants from overnight culture were measured, and Triton X-100-induced autolysis of SE1457-△arlS was performed. Results The plasmid pBT2-△arlS was constructed and arlS gene was deleted from the genome of S. epidermidis 1457 strain. The growth curve of wild type 5. epidermidis strain and SE1457-△arlS were similar, which indicates that arlS mutant has no obvious effect on the proliferation of S. epidermidis . However, as compared with wild type strain, SE1457-△arlS has lower capacity of biofilm formation. After induction by 0. 1%Triton X-100, the lytic percentage of SE1457-△arlS and the wild strain was 97.83% and 55.38% respectively. However, bacteriolytic activity of the overnight culture supernatant from SE1457-△arlS is lower than that of the wild strain. Conclusion arlS gene of the arlS/R two-component signal transduction system of S. epidermidis can regulate bacterial biofilm formation, autolysis and extracellular bacteno-lytic activity.