The role of DNA base excision repair in filamentation in Escherichia coli K-12 adhered to epithelial HEp-2 cells
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Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species generated by chemical and physical agents or by metabolism which can react with DNA and cause a variety of mutations. Epithelial cells are typically the first type of host cell to come into contact with potential microbial invaders. In this work, we have evaluated whether the adherence to human epithelial cells causes DNA damage and associated filamentation. Experiments concerning adherence to HEp-2 cells were carried out with mutants deficient in BER that were derived from Escherichia coli K-12. Since the removal of mannose during bacterial interaction with HEp-2 cells allows adhesion through mannose-sensitive adhesins, the experiments were also performed in the presence and the absence of mannose. Our results showed enhanced filamentation for the single xth (BW9091) and triple xth nfo nth (BW535) mutants in adherence assays with HEp-2 cells performed without d-mannose. The increased filamentation growth was inhibited by complementation of BER mutants with a wild type xth gene. Moreover, we measured SOS induction of bacteria adhered to HEp-2 cells in the presence and absence of d-mannose through of SOS-chromotest assay and we observed a higher β-galactosidase expression in the absence of mannose. In this context, data showed evidence that bacterial attachment to HEp-2 epithelial surfaces can generate DNA lesions and SOS induction.
KeywordsBase excision repair Escherichia coli K-12 adherence HEp-2 cells SOS response Filamentation
This work was supported by grant from FAPERJ, CNPq, CAPES, SR-2/UERJ and Programa de Núcleo de Excelência (PRONEX) of the Brazilian Ministry of Science and Technology. We thank Bernard Weiss for generously providing the bacterial strains and plasmids. We are also grateful to Maria Angélica Pereira da Silva and Wagner Oliveira Brito for technical assistance.
- Friedberg EC, Walker GC, Siede W, Wood RD, Schultz RA, Ellenberger T (2006) DNA repair and mutagenesis 2nd edn. ASM Press, Washinton DCGoogle Scholar
- Justice SS, Hunstad DA, Cegelski L, Hultgreen SJ (2008) Morphological plasticity as a bacterial survival strategy. Nature 6:162–168Google Scholar
- Sambrook J, Russell DW (2001) Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, LondonGoogle Scholar
- Wallace SS (1997) Oxidative damage to DNA and its repair. In: Scandalios JG (ed) Oxidative stress and the molecular biology of antioxidant defenses. Cold Spring Harbor Laboratory, Cold Spring Harbor, pp 49–90Google Scholar
- Xianhua Y, Feng Y, Wheatcroft R, Chambers J, Gong J, Gyles CL (2011) Adherence of Escherichia coli O157: H7 to epithelial cells in vitro and in pig gut loops is affected by bacterial culture conditions. Can J Vet Res 75(2):81–88Google Scholar