Vachon Vincent, Schwartz Jean-Louis, Laprade Raynald
Groupe d'étude des protéines membranaires and Biocontrol Network, Université de Montréal, P.O. Box 6128, Centre Ville Station, Montreal, Quebec, Canada H3C 3J7.
J Invertebr Pathol. 2006 Jul;92(3):160-5. doi: 10.1016/j.jip.2006.06.001.
The effect of Bacillus thuringiensis toxins on the permeability of the luminal membrane of Manduca sexta midgut columnar epithelial cells is strongly influenced by several biophysical and biochemical factors, including pH, ionic strength, and divalent cations, suggesting an important role for electrostatic interactions. The influence of these factors can differ greatly, however, depending on the toxin being studied, even for closely related toxins such as Cry1Ac and Cry1Ca. In the present study, the possibility of using temperature changes as a tool for controlling the rate and extent of pore formation in midgut brush border membrane vesicles was evaluated. Lowering temperature gradually decreased the rate of pore formation, but had little effect on the permeability of vesicles previously incubated with toxin at room temperature. The formation of new pores, following incubation of the vesicles with toxin, could thus be almost abolished by rapidly cooling the vesicles to 2 degrees C. Using this approach, changes in the rate of pore formation could be more easily distinguished from alterations in the properties of the pores formed, thus allowing a more detailed analysis of the kinetics and mechanism of pore formation.
苏云金芽孢杆菌毒素对烟草天蛾中肠柱状上皮细胞腔膜通透性的影响受到多种生物物理和生化因素的强烈影响，包括pH值、离子强度和二价阳离子，这表明静电相互作用起着重要作用。然而，这些因素的影响可能差异很大，具体取决于所研究的毒素，即使是Cry1Ac和Cry1Ca等密切相关的毒素也是如此。在本研究中，评估了利用温度变化作为控制中肠刷状缘膜囊泡孔形成速率和程度的工具的可能性。降低温度会逐渐降低孔形成的速率，但对先前在室温下与毒素孵育的囊泡的通透性影响很小。因此，通过将囊泡快速冷却至2摄氏度，几乎可以消除囊泡与毒素孵育后新孔的形成。使用这种方法，可以更容易地区分孔形成速率的变化与已形成孔的性质的改变，从而更详细地分析孔形成的动力学和机制。
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