Pore formation activity of Cry1Ab toxin from Bacillus thuringiensis in an improved membrane vesicle preparation from Manduca sexta midgut cell microvilli

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• 作者：Bravo ; Alejandra ; Miranda ; Raú ; l ; G&oacute ; mez ; Isabel ; Sober&oacute ; n ; Mario
• 关键词：Bacillus thuringiensis ; Pore formation ; Microvilli ; Brush border membrane vesicle
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2002
• 出版时间：May 3, 2002
• 年：2002
• 卷：1562
• 期：1-2
• 页码：63-69
• 全文大小：186 K

文摘

The pore formation activity of Cry1Ab toxin is analyzed in an improved membrane preparation from apical microvilli structures of Manduca sexta midgut epithelium cells (MEC). A novel methodology is described to isolate MEC and brush border membrane vesicles (BBMV) from purified microvilli structures. The specific enrichment of apical membrane enzyme markers aminopeptidase (APN) and alkaline phosphatase (APh) were 35- and 22-fold, respectively, as compared to the whole midgut cell homogenate. Ligand-blot and Western-blot experiments showed that Cry1A specific receptors were also enriched. The pore formation activity of Cry1Ab toxin was fourfold higher in the microvilli membrane fraction that showed low intrinsic K⁺ channels and higher APN and APh activities than in the basal-lateral membrane fraction harboring high intrinsic K⁺ channels. These data suggest that basal-lateral membrane was separated from apical membrane.