Selection and molecular characterization of Bacillus thuringiensis strains efficient against soybean looper (Chrysodeixis includens) and Spodoptera species

ABSTRACT Soybean looper (Chrysodeixis includens) and Spodoptera group are important defoliators insects responsible for significant yield losses in soybean, cotton and maize in Brazil. Bioinsecticides and transgenic plants expressing insecticidal proteins from Bacillus thuringiensis are among the most used sustainable control methods for pest control in agriculture, especially for several lepidopteran species. To provide new components for insect control, this study aimed to select and characterize B. thuringiensis strains toxic to C. includens, S. cosmioides, S. eridania, and S. frugiperda. We performed initial bioassays with fifty B. thuringiensis strains for C. includens and selected four strains - 1608A, 726, 773, and 775E - that caused high larval mortality (100%) to be tested against Spodoptera species. These strains harbored cry insecticidal genes, megaplasmids, absence of β-exotoxin and showed two major proteins about 65 and 130 kDa in SDS-page attributed to Cry protein classes toxic to lepidopteran species. The 1608A and 775E strains also showed high toxicity to Spodoptera species that demonstrate great potential for B. thuringiensis-based bioproduct development and as sources of new insecticidal genes for transgenic crops for multiple pest control relevant in the Brazilian agricultural system.

The Study and Design Methods of Serum-Free Medium for Animal Cells / 中国生物工程杂志

With the expanding scale of animal cell culture and increasing demand of biopharmaceutical,the development of serum-free medium based on cell lines and products has become a major task in the field of cell engineer.The statistical methods and tools are popular in the processes of design medium and can be used to evaluate the multiple factors and their interaction scientifically and effectively.The novel microarray and proteomic analysis can improve the performance of identifying the role of medium.The aim is to provide some idea for serum-free medium study through systematically summarizing the newly and commonly used serum-free medium study and design approaches and their characteristics.

An Emerging Method for Characterizing Microbial Ecology-T-Rflp Technique / 微生物学通报

Terminal restriction fragment length polymorphism(T-RFLP) is a resent molecular approach that can assess subtle genetic differences between strains as well as provide insight into the structure and function of microbial communities. This method overcomes the confinement of conventional culture-dependent methods and has both high sensitivity and throughput making it ideal for comparative analyses. Though there is still no application in our country, more and more investigators are highlighting it. In this article, the fundamental principle of this technique is introduced. The recent application and the development of this technique are also summed up .