Secretion of Ipa proteins by Shigella flexneri: Inducer molecules and kinetics of activation
Secretion of Ipa proteins by Shigella flexneri: Inducer molecules and kinetics of activation
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DOI：
10.1128/iai.65.10.4005-4010.1997
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发表时间：
1997-10-01
影响因子：
3.1
通讯作者：
Parsot, C
中科院分区：
文献类型：
--
作者：
Bahrani, FK;Sansonetti, PJ;Parsot, C
福氏志贺菌的III型Mxi-Spa分泌机制负责分泌Ipa蛋白，其参与细菌进入上皮细胞。ipa蛋白在实验室培养基中生长的细菌内积累，并且当细菌与真核细胞接触时，它们的分泌被激活。在这项研究中，我们已经确定了一组化合物，包括刚果红，埃文斯蓝，和直接橙子，这是能够诱导分泌的Ipa蛋白的细菌悬浮在磷酸盐缓冲盐水。刚果红激活Ipa分泌的动力学参数通过用酶联免疫吸附测定法测量分泌的IpaC的量和通过研究Ipa蛋白对蛋白酶K降解的敏感性的增加来确定。Ipa分泌发生在37 ℃，用5至10 μ M刚果红获得，并在30分钟内完成。此外，在整个生长指数期收获的细菌中观察到刚果红对Ipa分泌的激活，但在稳定期收获的细菌中没有观察到。刚果红和刚果红相关化合物与Mxi-Spa分泌装置的相互作用可能是特异性疏水相互作用，类似于刚果红与淀粉样蛋白结合的相互作用。
The type III Mxi-Spa secretion machinery of Shigella flexneri is responsible for secretion of Ipa proteins, which are involved in the entry of bacteria into epithelial cells. Ipa proteins accumulate within bacteria growing in laboratory media, and their secretion is activated upon contact of bacteria with eukaryotic cells. In this study, we have identified a group of chemical compounds, including Congo red, Evans blue, and direct orange, which are able to induce secretion of Ipa proteins by bacteria suspended in phosphate-buffered saline. Parameters of kinetics of activation of Ipa secretion by Congo red were determined by measuring by enzyme-linked immunosorbent assay the amount of IpaC secreted and by investigating the increase in susceptibility of Ipa proteins to proteinase K degradation. Ipa secretion occurred at 37 degrees C, was obtained with 5 to 10 mu M Congo red, and was complete within 30 min, In addition, activation of Ipa secretion by Congo red was observed with bacteria harvested throughout the exponential phase of growth but not with bacteria in the stationary phase. The interactions of Congo red and Congo red-related compounds with the Mxi-Spa secretion apparatus might be specific hydrophobic interactions similar to those involved in binding of Congo red to amyloid proteins.