The role of periplasmic antioxidant enzymes (superoxide dismutase and thiol peroxidase) of the Shiga toxin-producing Escherichia coli O157:H7 in the formation of biofilms
The role of periplasmic antioxidant enzymes (superoxide dismutase and thiol peroxidase) of the Shiga toxin-producing Escherichia coli O157:H7 in the formation of biofilms
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DOI：
10.1002/pmic.200600320
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发表时间：
2006-12-01
期刊：
影响因子：
3.4
通讯作者：
Park, Woojun
中科院分区：
文献类型：
--
作者：
Kim, Young Hoon;Lee, Yunho;Park, Woojun
本研究探讨了周质氧化防御蛋白，铜，锌超氧化物歧化酶（SodC）和巯基过氧化物酶（Tpx）的作用，从滋贺毒素生产大肠杆菌O 157：H7（STEC）在生物膜的形成。蛋白质组学分析显示，在生物膜条件下生长的STEC细胞中，两种周质抗氧化系统（SodC和Tpx）的表达水平均显著高于非生物膜条件下。它们的生长阶段依赖的基因表达的分析表明，高水平的sodC的表达发生在稳定期，并强烈诱导tpx基因的表达仅在指数生长期。外源过氧化氢减少STEC sodC和tpx突变体的有氧生长超过其亲本菌株。这两个突变体也显示出显着减少，其附着在生物（HT-29上皮细胞）和非生物表面（聚苯乙烯和聚氯乙烯微孔板）在静态有氧生长。然而，在有氧生长条件下，野生型和突变体的生长速率相似。与STEC sodC和tpx突变体相比，仅在玻璃毛细管中的野生型STEC细胞在连续流动培养条件下观察到STEC生物膜的形成。据我们所知，这是第一个突变研究，以显示sodC和tpx基因产物的贡献，形成一个E。coli O 157：H7生物膜。这些结果还表明，这些生物膜是生理异质性的，并且在指数和静止生长阶段的氧化应激防御在STEC生物膜的形成中起重要作用。
This study examined the role of the periplasmic oxidative defense proteins, copper, zinc superoxide dismutase (SodC), and thiol peroxidase (Tpx), from the Shiga toxin-producing Escherichia coli O157:H7 (STEC) in the formation of biofilms. Proteomic analyses have shown significantly higher expression levels of both periplasmic antioxidant systems (SodC and Tpx) in STEC cells grown under biofilm conditions than under planktonic conditions. An analysis of their growth phase-dependent gene expression indicated that a high level of the sodC expression occurred during the stationary phase and that the expression of the tpx gene was strongly induced only during the exponential growth phase. Exogenous hydrogen peroxide reduced the aerobic growth of the STEC sodC and tpx mutants by more than that of their parental strain. The two mutants also displayed significant reductions in their attachment to both biotic (HT-29 epithelial cell) and abiotic surfaces (polystyrene and polyvinyl chloride microplates) during static aerobic growth. However, the growth rates of both wild-type and mutants were similar under aerobic growth conditions. The formation of an STEC biofilm was only observed with the wild-type STEC cells in glass capillary tubes under continuous flow-culture conditions compared with the STEC sodC and tpx mutants. To the best of our knowledge, this is the first mutational study to show the contribution of sodC and tpx gene products to the formation of an E. coli O157:H7 biofilm. These results also suggest that these biofilms are physiologically heterogeneous and that oxidative stress defenses in both the exponential and stationary growth stages play important roles in the formation of STEC biofilms.