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- 作者：M.G. Leonardi ; P. Parenti ; M. Casartelli and B. Giordana
- 关键词：Key words ; CrylAa δ ; endotoxin — ; Bacillus thuringiensis— ; Bombyx mori larval midgut — ; K+/amino acid symporters — ; Brush border membrane vesicles — ; Isolated midgut
- 刊名：Journal of Membrane Biology
- 出版时间：October 1997
- 出版年：1997
- 期刊代码：145_0022-2631
- 类别：bio
- 卷：159
- 期：3
- 页码：209-217
- 数据来源：sp
摘要
We have examined the type of inhibition exerted by an activated preparation of the Bacillus thuringiensisδ-endotoxin CrylAa on K+-dependent leucine transport into midgut brush border membrane vesicles or epithelial cells of the isolated midgut from Bombyx mori to study its possible interaction with the amino acid symporter. K+ permeability and the cation-dependent amino acid translocation into brush border membrane vesicles were evaluated by monitoring the fluorescence of the voltage-sensitive cyanine dye 3,3′-dipropylthiadicarbocyanine iodide. The symporter ability to accept Na+ instead of K+ was exploited and the dissipation of an imposed inside-negative potential (K+ gradient in>out and valinomycin) was registered in the presence of a Na+ gradient (out>in) and of the amino acid. The fluorescence quenching dissipated more rapidly when the amino acid was present. Preincubation of brush border membrane vesicles with CrylAa caused a significant decrease of the amino acid-dependent recovery of fluorescence, whereas K+ permeability was sparely affected.