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苏云金芽胞杆菌(Bacillus thuringiensis,Bt)制剂是目前产量最大、应用最广泛的微生物杀虫剂,但在施用过程中易受紫外线的影响而缩短持效期,成为Bt制剂应用受限的主要原因之一。本研究以纳米Mg(OH)2为载体,将其与Bt杀虫晶体蛋白进行负载,研究纳米Mg(OH)2负载Bt杀虫晶体蛋白后的生物杀虫活性及抗紫外能力。以共沉淀法制备纳米Mg(OH)2,利用X-射线粉末衍射(X-ray powder diffraction,XRD)对其尺寸进行表征,通过谢乐公式计算得出合成的纳米颗粒在101面的尺寸为12 nm。扫描电镜(scanning electron microscope,SEM)的结果表明,纳米颗粒为较规则的片状结构且分散均匀,与Cry蛋白负载后,其形貌没有发生明显的变化。以高效杀蚊Bt菌株LLP29为供试菌株,利用碱溶法获得Bt杀虫晶体蛋白。通过十二烷基硫酸钠聚丙烯酰胺(sodium dodecyl sulfonate-polyacrylamide gelelectrophoresis,SDS-PAGE)和生物活性测试结果表明,Bt杀虫晶体蛋白与纳米Mg(OH)2进行一定负载后,能有效地提高其Cry蛋白的杀虫活性,同时增强抗紫外辐射能力,有效地保护蛋白结构免受破坏。本研究为获得生物相容性好、环境友好的纳米Bt高效制剂提供了理论基础。
Bacillus thuringiensis (Bt) is currently the largest and most widely used microbial insecticide, but it is susceptible to ultraviolet light and shortens the duration of persistence during application, which is the main reason for the limited application of Bt preparation one. In this study, nano-Mg (OH) 2 was used as a carrier to load Bt insecticidal crystal protein. The biocidal activity and UV-resistance of Bt insecticidal crystal protein loaded with Mg (OH) 2 were studied. Nanometer Mg (OH) 2 was prepared by co-precipitation method and its size was characterized by X-ray powder diffraction (XRD). The size of synthesized nano-particles on the 101 surface was 12 nm. The results of scanning electron microscopy (SEM) showed that the nanoparticles were more regular sheet-like structure and dispersed evenly, and the morphology of the nanoparticles did not change significantly after loading with Cry protein. Bt insecticidal crystal protein was obtained by alkaline solution with efficient killing mosquito Bt strain LLP29 as tested strain. SDS-PAGE and bioassay results showed that Bt insecticidal crystal protein and nano-Mg (OH) 2 could effectively increase Its Cry protein insecticidal activity, while enhancing the ability of UV radiation, effectively protect the protein structure from damage. This study provides a theoretical basis for obtaining a highly biocompatible and environment-friendly nano-Bt high efficiency preparation.