Metabolomic Characterization of a cf. Neolyngbya Cyanobacterium from the South China Sea Reveals Wenchangamide A,a Lipopeptide with In Vitro Apoptotic Potential in Colon Cancer Cells

Metabolomics can be used to study complex mixtures of natural products, or secondary metabolites, for many different purposes. One productive application of metabolomics that has emerged in recent years is the guiding direction for isolating molecules with structural novelty through analysis of untargeted LC-MS/MS data. The metabolomics-driven investigation and bioassay-guided fractionation of a biomass assemblage from the South China Sea dominated by a marine filamentous cyanobacteria, cf. Neolyngbya sp., has led to the discovery of a natural product in this study, wenchangamide A (1). Wenchangamide A was found to concentration-dependently cause fast-onset apoptosis in HCT116 human colon cancer cells in vitro (24 h IC₅₀ = 38 μM). Untargeted metabolomics, by way of MS/MS molecular networking, was used further to generate a structural proposal for a new natural product analogue of 1, here coined wenchangamide B, which was present in the organic extract and bioactive sub-fractions of the biomass examined. The wenchangamides are of interest for anticancer drug discovery, and the characterization of these molecules will facilitate the future discovery of related natural products and development of synthetic analogues.     

中泰非英语专业学生英语词义发现策略对比研究

词义发现策略是英语词汇学习和记忆策略的重要内容。本文旨在对中国和泰国非英语专业学生在英语学习过程中使用词义发现策略的总体情况进行对比研究。399名来自中泰两所大学的非英语专业的学生参加了这项研究。数据收集方法包括“词汇发现策略调查问卷”和词汇水平测试。研究发现：中泰非英语专业学生词义发现策略的总体使用频率不是很高;在三类词义发现策略的使用上,中国学生在猜词策略和社会策略的使用上高于泰国学生,而泰国学生在词典策略的使用上高于中国学生;中泰非英语专业学生词义发现策略使用的性别差异不明显;猜词策略和词典策略能够较好地预测英语词汇水平测试成绩。     

The OryzaSNP Project-SNP Discovery in Diverse Rice

The OryzaSNP project （http：//www.oryzasnp.org） is undertaking SNP discovery across the entire rice genome for 20 diverse varieties （McNally et al., 2006）. These varieties include representatives from the indica, tropical and temperate japonicas, aus, deepwater, and aromatic types of rice. SNPs are identified by array-based re-sequencing technology using very high-density oligomer arrays at Perlegen （Patil et al., 2001; Hinds et al., 2005）. SNPs arc called as those bases where hybridization of the target line differs from that of the Nipponbare reference genome. Release 4 of the Nipponbare sequence （The International Rice Genome Sequencing Project, 2005） was first masked for repetitive DNA, the segments remaining after masking were each blasted to the unmasked genome, and those that gave a single or a few hits were selected. After this filtering, 100 Mb of the rice genome is tiled onto arrays for SNP detection. Since long-range PCR is being used to prepare target DNA for hybridization, amplicons were chosen that span both unique sequence and TIGR gene models （Yuan et al., 2005） to define the final sequence for tiling. There is usually at least one LR-PCR amplicon in every 100 kb window. From this analysis,     

Emerging Strategies and Integrated Systems Microbiology Technologies for Biodiscovery of Marine Bioactive Compounds

Marine microorganisms continue to be a source of structurally and biologically novel compounds with potential use in the biotechnology industry. The unique physiochemical properties of the marine environment (such as pH, pressure, temperature, osmolarity) and uncommon functional groups (such as isonitrile, dichloroimine, isocyanate, and halogenated functional groups) are frequently found in marine metabolites. These facts have resulted in the production of bioactive substances with different properties than those found in terrestrial habitats. In fact, the marine environment contains a relatively untapped reservoir of bioactivity. Recent advances in genomics, metagenomics, proteomics, combinatorial biosynthesis, synthetic biology, screening methods, expression systems, bioinformatics, and the ever increasing availability of sequenced genomes provides us with more opportunities than ever in the discovery of novel bioactive compounds and biocatalysts. The combination of these advanced techniques with traditional techniques, together with the use of dereplication strategies to eliminate known compounds, provides a powerful tool in the discovery of novel marine bioactive compounds. This review outlines and discusses the emerging strategies for the biodiscovery of these bioactive compounds.     

Biological characterization of sulfoxaflor, a novel insecticide

BACKGROUND: The commercialization of new insecticides is important for ensuring that multiple effective product choices are available. In particular, new insecticides that exhibit high potency and lack insecticidal cross‐resistance are particularly useful in insecticide resistance management (IRM) programs. Sulfoxaflor possesses these characteristics and is the first compound under development from the novel sulfoxamine class of insecticides. RESULTS: In the laboratory, sulfoxaflor demonstrated high levels of insecticidal potency against a broad range of sap‐feeding insect species. The potency of sulfoxaflor was comparable with that of commercial products, including neonicotinoids, for the control of a wide range of aphids, whiteflies (Homoptera) and true bugs (Heteroptera). Sulfoxaflor performed equally well in the laboratory against both insecticide‐susceptible and insecticide‐resistant populations of sweetpotato whitefly, Bemisia tabaci Gennadius, and brown planthopper, Nilaparvata lugens (Stål), including populations resistant to the neonicotinoid insecticide imidacloprid. These laboratory efficacy trends were confirmed in field trials from multiple geographies and crops, and in populations of insects with histories of repeated exposure to insecticides. In particular, a sulfoxaflor use rate of 25 g ha^?1 against cotton aphid (Aphis gossypii Glover) outperformed acetamiprid (25 g ha^?1) and dicrotophos (560 g ha^?1). Sulfoxaflor (50 g ha^?1) provided a control of sweetpotato whitefly equivalent to that of acetamiprid (75 g ha^?1) and imidacloprid (50 g ha^?1) and better than that of thiamethoxam (50 g ha^?1). CONCLUSION: The novel chemistry of sulfoxaflor, its unique biological spectrum of activity and its lack of cross‐resistance highlight the potential of sulfoxaflor as an important new tool for the control of sap‐feeding insect pests. Copyright © 2010 Society of Chemical Industry     

《植物病理学》课程教改的探索与实践

在植物病理学的教学中,经过多年的教学探索实践表明,启发式教学能够调动学生的学习积极性、提高学生分析问题和解决问题的能力;自主式教学可以拓宽学生的知识面、了解本学科的最新进展;发现式教学可以激发学生的智力潜力、培养学生自我激励的内在动机、增强学生的责任心;自我评价式教学不但可以提高学生与他人的交流技巧,而且可以提高学生的人文修养。