Investigations were done on the usefulness of Envirologix CrylAb/CrylAc Plate kits for quantitative analysis of Bt toxin content in transgenic rice grains. Two transgenic rice lines: Kemingdao 1 (KMD1) and Kemingdao 2...Investigations were done on the usefulness of Envirologix CrylAb/CrylAc Plate kits for quantitative analysis of Bt toxin content in transgenic rice grains. Two transgenic rice lines: Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2), transformed with a crylAb gene, and their parental variety, cv. Xiushui 11, were used as positive and negative samples. Results showed that the correlation coefficients as high as 0. 985 - 0. 998, significant at probability level of 0. 05 or 0.01, were obtained for linear regression equations by using the appended calibrators of the kits. No significant differences were detected for values of same rice sample obtained from different trials or by using different lots of the product (kit). The detectable Bt toxin content by this method could be as low as 0.5 ng/g. The Envirologix Kit could be useful for rapid quantitative detection of Bt toxin in rice grains because of its preciseness, simplicity and time saving.展开更多
为了构建对敏感和类钙粘蛋白突变的抗性昆虫都具有高杀虫活性的毒素,将Cry1Ac毒素结构域I中α1和α2之间插入一个α胰凝乳蛋白酶作用位点,并分析突变体毒素在苏云金芽孢杆菌中形成伴孢晶体、目标蛋白的表达情况,以及鉴定突变体毒素的杀...为了构建对敏感和类钙粘蛋白突变的抗性昆虫都具有高杀虫活性的毒素,将Cry1Ac毒素结构域I中α1和α2之间插入一个α胰凝乳蛋白酶作用位点,并分析突变体毒素在苏云金芽孢杆菌中形成伴孢晶体、目标蛋白的表达情况,以及鉴定突变体毒素的杀虫活性。结果发现:4个突变体蛋白都能在苏云金芽孢杆菌中表达产生约130 k Da的目标蛋白,但不能形成有规则的伴孢晶体。这可能是由于突变体蛋白在Bt生长的平稳期达到最高,在衰亡期开始被降解造成的。4个突变体中,Cry1Acm4在培养48 h时产量最高,而且其对甜菜夜蛾杀虫活性比野生型高1.6倍,但是其产量只有野生型毒素产量的十分之一。尽管由于Cry1Acm4的表达量较低而使其实际应用的价值不大,但这种构建突变体的方法对研究高毒力的Cry1Ac毒素提供一种新的思路。展开更多
The potential effects of insect-resistant, genetically engineered （GE） crops on non-target organisms, especially on predators and parasitoids, must be evaluated before their commercial cultivation. The effects of GE...The potential effects of insect-resistant, genetically engineered （GE） crops on non-target organisms, especially on predators and parasitoids, must be evaluated before their commercial cultivation. The effects of GE maize that produces CrylAc toxin on the parasitoid Macrocentrus cingulum were assessed by direct bioassay and indirect bioassay. In the indirect bioassay, parasitism rate, cocoon weight and the number of M. cingu- lure progeny produced per host were significantly reduced when M. cingulum-parasitized CrylAc-susceptible Ostriniafurnacalis were fed a diet containing purified CrylAc; how- ever, life-table parameters of M. cingulum were not adversely affected when the same assay was performed with Cry 1Ac-resistant （9. furnacalis. These results indicated that the detrimental effects detected with a CrylAc-susceptible host were mediated by poor host quality. In a direct bioassay, no difference in life-table parameters were detected when M. cingulum adults were directly fed a 20% honey solution with or without CrylAc; however, survival and longevity were significantly reduced when M. cingulum adults were fed a honey solution containing potassium arsenate, which was used as a positive control. The stability and bioactivity of CrylAc toxin in the food sources and CrylAc toxin uptake by the host insect and parasitoid were confirmed by enzyme-linked immunosorbent assay and sensitive-insect bioassays. Our results demonstrate that M. cingulum is not sensitive to CrylAc toxin at concentrations exceeding those encountered in Bacillus thuringiensis maize fields. This study also demonstrates the power of using resistant hosts when assess- ing the risk of genetically modified plants on non-target organisms and will be useful for assessing other non-target impacts.展开更多
文摘Investigations were done on the usefulness of Envirologix CrylAb/CrylAc Plate kits for quantitative analysis of Bt toxin content in transgenic rice grains. Two transgenic rice lines: Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2), transformed with a crylAb gene, and their parental variety, cv. Xiushui 11, were used as positive and negative samples. Results showed that the correlation coefficients as high as 0. 985 - 0. 998, significant at probability level of 0. 05 or 0.01, were obtained for linear regression equations by using the appended calibrators of the kits. No significant differences were detected for values of same rice sample obtained from different trials or by using different lots of the product (kit). The detectable Bt toxin content by this method could be as low as 0.5 ng/g. The Envirologix Kit could be useful for rapid quantitative detection of Bt toxin in rice grains because of its preciseness, simplicity and time saving.
文摘为了构建对敏感和类钙粘蛋白突变的抗性昆虫都具有高杀虫活性的毒素,将Cry1Ac毒素结构域I中α1和α2之间插入一个α胰凝乳蛋白酶作用位点,并分析突变体毒素在苏云金芽孢杆菌中形成伴孢晶体、目标蛋白的表达情况,以及鉴定突变体毒素的杀虫活性。结果发现:4个突变体蛋白都能在苏云金芽孢杆菌中表达产生约130 k Da的目标蛋白,但不能形成有规则的伴孢晶体。这可能是由于突变体蛋白在Bt生长的平稳期达到最高,在衰亡期开始被降解造成的。4个突变体中,Cry1Acm4在培养48 h时产量最高,而且其对甜菜夜蛾杀虫活性比野生型高1.6倍,但是其产量只有野生型毒素产量的十分之一。尽管由于Cry1Acm4的表达量较低而使其实际应用的价值不大,但这种构建突变体的方法对研究高毒力的Cry1Ac毒素提供一种新的思路。
文摘The potential effects of insect-resistant, genetically engineered （GE） crops on non-target organisms, especially on predators and parasitoids, must be evaluated before their commercial cultivation. The effects of GE maize that produces CrylAc toxin on the parasitoid Macrocentrus cingulum were assessed by direct bioassay and indirect bioassay. In the indirect bioassay, parasitism rate, cocoon weight and the number of M. cingu- lure progeny produced per host were significantly reduced when M. cingulum-parasitized CrylAc-susceptible Ostriniafurnacalis were fed a diet containing purified CrylAc; how- ever, life-table parameters of M. cingulum were not adversely affected when the same assay was performed with Cry 1Ac-resistant （9. furnacalis. These results indicated that the detrimental effects detected with a CrylAc-susceptible host were mediated by poor host quality. In a direct bioassay, no difference in life-table parameters were detected when M. cingulum adults were directly fed a 20% honey solution with or without CrylAc; however, survival and longevity were significantly reduced when M. cingulum adults were fed a honey solution containing potassium arsenate, which was used as a positive control. The stability and bioactivity of CrylAc toxin in the food sources and CrylAc toxin uptake by the host insect and parasitoid were confirmed by enzyme-linked immunosorbent assay and sensitive-insect bioassays. Our results demonstrate that M. cingulum is not sensitive to CrylAc toxin at concentrations exceeding those encountered in Bacillus thuringiensis maize fields. This study also demonstrates the power of using resistant hosts when assess- ing the risk of genetically modified plants on non-target organisms and will be useful for assessing other non-target impacts.
