Functional Gene Mutation And Expression As Well As Differentially Expressed Proteins Analysis Of The Naturally Occurred Mismatch Repair(MMR) System Deficient Foodborne Salmonella Hypermutators

Mismatch repair(MMR) system deficient Salmonella can not only exhibit promoted gene mutation opportunity, but also the frequency of horizontal gene transfer(HGT) to acquire antibiotic resistance and pathogenicity, and is great potential hazard to food safety and public health.In this study, mutation and expression of 20 genes associated with the mutation frequency,multi-drug resistance(MDR) and pathogenicity, and the proteomes of four MMR system deficient foodborne Salmonella hypermutators were analyzed for more information about this bacterium.Various numbers and types of mutations were detected in TolC, ParC, MutS, MutL, MutT,UvrD, HilA and OmpF, among which, mutations were commonly detected from MutL. In the contrary, genes AcrA, AcrB, AcrE, MarA, MarR, DnaQ, Gyr A, ParE, MutH, OmpR, SoxS did not identified mutation with amino acid substitution. Expression levels of mutS, marR and parC of the hypermutators increased, while those of acrB and mut H decreased. Mutation frequencies of the hypermutators were detected increased while the expression levels of their mutS, mutL, and uvrD decreased.One hundred and thirty seven differentially expressed protein spots and 110 specific proteins expressed only in hypermutators and 86 specific proteins expressed only in Salmonella typhimurium LT2, of which 68 spots were successfully identified based MS. A total of 38 spots were up-regulated in four hypermutators, whereas 11 spots were down-regulated and 19 spots were specific proteins. Some of 30 S ribosomal protein S1, S2 and S6 families and glycerol kinase,SSU ribosomal protein S2 p, molecular chaperone Dnak, short-chain dehydrogenase, periplasmic protein, phosphoglycerate kinase were simultaneously up-regulated, while elongation factor Ts,F0F1 ATP synthase subunit beta, 50 S ribosomal protein L7/L12, lysyl-tRNA synthetase,alpha-hilical coiled coil protein and flagellin were down-regulated in hypermutators. ExceptSalmonella typhimurium LT2, the specific proteins of elongation factor Tu, transcriptional regulator, OmpX, Omp A glycerol kinase, peptidase PmbA in 31, Omp A, flagellin, periplasmic protein, phosphoglyceromutase in 1171 R, Flagellar synthesis, isocitrate dehydrogenase, Protein yciF in S8XC001 a, and ranscription termination factor Rho and cold shock protein in 103 D were identified only in hypermutators.Our data comprehensively deciphered the proteomes, functional gene mutations and expression associated with increased mutation and multi-drug resistance in MMR system deficient Salmonella, and supported helpful information for food safety control.