Wang Haiyan, Ye Qingfu, Gan Jay, Wu Jianmin
Institute of Nuclear Agricultural Sciences, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China.
J Agric Food Chem. 2008 Jun 25;56(12):4659-64. doi: 10.1021/jf800162s. Epub 2008 May 31.
Adsorption on a soil matrix of the insecticidal protein from Bacillus thuringiensis ( Bt) transgenic plants affects their accumulation and release and, hence, bioavailability in soil. Cry1Ab protein isolated from Bt transgenic rice was used to evaluate the adsorption and desorption on bentone, kaolin, and humic acids (HAs). The adsorption equilibrium of Cry1Ab protein was reached within 1-2 h for bentone and kaolin and within 4-8 h for HAs. The adsorption isotherms were better described by linear expressions ( R (2) >/= 0.973) rather than by the Freundlich model. No saturation was observed, even at the maximum concentration used (3.71 microg mL (-1)). The adsorbed protein was not easily desorbed at the used protein concentrations (0.18-3.71 microg mL (-1)); more than 50-70%, 70-80%, and 90% of the adsorbed protein remained on HAs, kaolin, and bentone, respectively, after washing with water. Adsorption and desorption of the Cry1Ab protein were further studied using five soils, and the isotherms were also well-described by linear equations ( p < 0.05). Adsorption of the Cry1Ab protein on soils was positively related to the soil organic matter content.
来自苏云金芽孢杆菌（Bt）转基因植物的杀虫蛋白在土壤基质上的吸附会影响其积累和释放，进而影响其在土壤中的生物有效性。从Bt转基因水稻中分离出的Cry1Ab蛋白用于评估其在膨润土、高岭土和腐殖酸（HAs）上的吸附和解吸情况。Cry1Ab蛋白在膨润土和高岭土上1 - 2小时内达到吸附平衡，在腐殖酸上4 - 8小时内达到吸附平衡。吸附等温线用线性表达式（R(2)≥0.973）比用弗伦德利希模型描述得更好。即使在使用的最大浓度（3.71微克/毫升(-1)）下也未观察到饱和现象。在所使用的蛋白质浓度（0.18 - 3.71微克/毫升(-1)）下，吸附的蛋白质不易解吸；用水洗涤后，分别有超过50 - 70%、70 - 80%和90%吸附在腐殖酸、高岭土和膨润土上的蛋白质仍留在上面。使用五种土壤进一步研究了Cry1Ab蛋白的吸附和解吸情况，等温线也能用线性方程很好地描述（p < 0.05）。Cry1Ab蛋白在土壤上的吸附与土壤有机质含量呈正相关。
