【摘要】 目的探讨表皮葡萄球菌atlE基因编码的AtlE蛋白介导生物膜起始黏附的相关机制。方法采用RT-PCR法检测表皮葡萄球菌atlE基因在不同时期的表达水平,用紫外分光光度计检测DNA的方法检测了相应时期的胞外DNA的释放量,并用DNA酶(DNaseⅠ)研究表皮葡萄球菌胞外DNA在生物膜形成和起始黏附中的作用;采用pBT2质粒同源重组敲除的方法构建了表皮葡萄球菌1457的atlE基因突变株,研究atlE基因敲除突变对起始黏附能力、生物膜形成及胞外DNA释放能力的影响。结果表皮葡萄球菌atlE基因的表达与胞外DNA的释放量有相关性;DNA酶能影响未成熟生物膜且能降低起始黏附能力;ΔatlE菌株胞外DNA的释放减少,起始黏附能力明显降低,不形成生物膜。结论表皮葡萄球菌atlE基因编码的AtlE蛋白能通过释放胞外DNA在表皮葡萄球菌的生物膜起作用。更多还原

【Abstract】 Purpose To illuminate the mechanism of Staphylococcus epidermidis AtlE protein encoded by atlE gene mediating primary attachment. Methods S.epidermidis atlE gene expression level at different phases was detected by RT-PCR,and the accumulation of extracellular DNA at different phases was assessed by spectrophotometric measurements of light absorbance by DNA;DNase Ⅰ was used to study the function of extracellular DNA in biofilm formation and primary attachment.The effects of atlE gene deletion on initial adherent capacity,biofilm formation and extracellular DNA release were studied by construction of atlE deletion mutant via homologous recombination. Results There existed the correlation between atlE gene expression and the quantity of extracellular DNA releasing into the medium,and DNase Ⅰ affected biofilm formation and reduced initial adherent capacity of S.epidermidis.The atlE mutant strain displayed the reduced capacity of extracellular DNA release and initial adherence and biofilm-formation deficiency. Conclusions AtlE protein plays an indirect role in S.epidermidis biofilm formation by releasing extracellular DNA.更多还原