Study On The Regulation Of Matrine To AI-2 Signaling Molecule Of Quorum Sensing System Of Staphylococcus Epidermidis

Antibiotics play an important role in treatment bacterial infection for a long time.But due to using antibiotics indiscriminately and irrationally,bacteria have serious drug resistance,even arisen multi drug resistant strains.Along with deeping research on the mechanism of bacterial drug resistance,it was found that drug resistance and bacterial biofilm have a great relationship.Once the biofilm is formed,bacterial resistance to antibiotics is increased over 1000 times than that of planktonic bacteria.Bacterial quorum sensing system can regulate the bacterial biofilm formation,AI-2 signaling molecule play an important role in quorum sensing,thus quorum sensing signaling molecule was a new target for inhibiting biofilm.This study chosen AI-2 signaling molecule as a research object,to study the formation rules of AI-2 signaling molecule and the effect characteristics of drug on AI-2 signaling molecule,then lay a foundation for the mechanism of traditional Chinese medicine inhibit bacterial biofilm.First,we used different culture methods to culture planktonic and biofilm bacteria of Staphylococcus epidermidis;then used spectrophotometer and XTT method to test growth curve of planktonic bacteria and biofilm bacteria respectively.We detected transcription level of luxS gene in this two different growth pattern by real-time PCR,and measured AI-2 signaling molecule activity by V.harveyi bioluminescence assay.We use these methods to study the chang rule of AI-2 signaling molecule activity and relative expression of luxS gene in different growth parttern.Mainly research how antibiotics,matrine and other traditional Chinese medicine regulate biofilm formation and AI-2 signaling molecule activity in two different cultivation mode of Staphylococcus epidermidis.Then study how glycerol monolaurate,n-nonanoic acid and combined use of matrine and this two compounds effect on biofilm formation and AI-2 signaling molecule.The result showed that AI-2 signaling molecule and the relative expression of luxS gene have different growth characteristics in this two different cultivating modes:in planktonic bacteria,AI-2 signaling molecule activity and the relative expression of luxS gene has positive correlation with bacteria growth process,however in biofilm bacteria there was negative correlation.It was found that the drugs have regulation function on the AI-2 signaling molecule after the drugs being used in the Staphylococcus epidermis AI-2 signaling molecule.And the inhibition of the drugs on the planktonic bacteria AI-2 signaling molecule was better than that of the biofilm bacteria.The inhibition of traditional Chinese medicine on AI-2 signaling molecule was better than antibiotics on AI-2 signaling molecule.Meanwhile,we found that durgs had inhibitory effect on biofilm bacteria to some extent.Glycerol monolaurate,n-nonanoic acid and composite of this two compound have inhibition on biofilm bacteria and AI-2 signaling molecule,and this compound have synergistic effect on inhibiting biofilm bacteria and AI-2 signaling molecule with matrine.