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Title:   Author  item
                                            YUN, JI-A - Hannam Universityitem
                                            CHOI, SEONG-HO - Hannam Universityitem
                                            Bearson, Bradley

                                                         - *Brad*item
                                            LEE, IN SOO - Hannam University
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 4/16/2012
                                    Publication  Date: 5/3/2012
                                    Citation: Yun, J., Choi, S., Bearson, B.L., Lee, I. 2012. The alternate sigma factor RpoS protects against silver ion toxicity in Salmonella enterica serovar Typhimurium. International Meeting of the Microbiological Society of Korea; 5/3-4/12; Seoul, Republic of Korea. p. 41.Interpretive Summary:
                                Technical Abstract: The alternative sigma factor, RpoS controls the expression of many stress response genes, including genes involved in acid and oxidative stresses. In this study, we demonstrated metal tolerance in S. enterica serovar Typhimurium, and silver ion showed the highest toxicity among the tested metal ions. Silver ion was able to inhibit bacterial growth or confer lethal effects to S. Typhimurium, with a minimal inhibitory concentration of 0.4 uM. Furthermore, an rpoS mutant displayed a dramatic susceptibility in a silver nitrate environment compared with the wild type strain. The rpoS mutant had a 4 log decrease in viability after 2 hours of exposure to silver ion. The gene expression of rpoS was analyzed using the beta-galactosidase assay and real time PCR. Based on the data, rpoS gene transcription was 4 times higher (Miller Units) in the silver containing medium. The tolerance and protective mechanisms of S. Typhimurium against metal toxicity, especially silver, is potentially related to an oxidative stress response including induction of rpoS.


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