Expression of three efflux pumps
AuthorWheeler, David Michael
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Drug efflux is a major mechanism of resistance to drugs in both cancer cells and pathogenic microorganisms. Consequently, there is an urgent need to understand the structure, function, and expression of the multidrug resistance pumps involved so that inhibitors can be designed to block drug extrusion. One of the most frequently employed resistance strategies in both prokaryotes and eukaryotes is the use of protein efflux pumps, reducing the intracellular drug concentration to sub-toxic levels. The plant signaling molecule salicylate has been shown to increase levels of resistance for several antibiotics and induce expression of multiple genes involved in antibiotic resistance. In this study using Erwinia chrysanthemi 3937 DE, salicylate increased antibiotic resistance of novobiocin and naladixic acid but had no affect on the detergents deoxycholate and sodium dodecyl sulfate resistance levels. Northern hybridization revealed that deoxycholate, sodium dodecyl sulfate, and salicylate increased emr, acr, yceE, and tolC expression while showing no increase for the antibiotics novobiocin and naladixic acid. This represents the first time efflux pump expression and native antibiotic resistance levels have been observed in E. chrysanthemi. This data will help in the further research of efflux pumps and their involvement in plant pathogenesis of E. chrysanthemi.