Discovery of natural products capable of inducing porcine host defense peptide gene expression using cell-based high throughput screening

Background: In-feed antibiotics are being phased out in livestock production worldwide. Alternatives to antibiotics are urgently needed to maintain animal health and production performance. Host defense peptides(HDPs) are known for their broad-spectrum antimicrobial and immunomodulatory capabilities. Enhancing the synthesis of endogenous HDPs represents a promising antibiotic alternative strategy to disease control and prevention.Methods: To identify natural products with an ability to stimulate the synthesis of endogenous HDPs, we performed a high-throughput screening of 1261 natural products using a newly-established stable luciferase reporter cell line known as IPEC-J2/pBD3-luc. The ability of the hit compounds to induce HDP genes in porcine IPEC-J2 intestinal epithelial cells, 3 D4/31 macrophages, and jejunal explants were verified using RT-qPCR. Augmentation of the antibacterial activity of porcine 3 D4/31 macrophages against a Gram-negative bacterium(enterotoxigenic E. coli) and a Gram-positive bacterium(Staphylococcus aureus) were further confirmed with four selected HDP-inducing compounds.Results: A total of 48 natural products with a minimum Z-score of 2.0 were identified after high-throughput screening,with 21 compounds giving at least 2-fold increase in luciferase activity in a follow-up dose-response experiment.Xanthohumol and deoxyshikonin were further found to be the most potent in inducing p BD3 m RNA expression,showing a minimum 10-fold increase in IPEC-J2, 3 D4/31 cells, and jejunal explants. Other compounds such as isorhapontigenin and calycosin also enhanced p BD3 m RNA expression by at least 10-fold in both IPEC-J2 cel s and jejunal explants, but not 3 D4/31 cells. In addition to p BD3, other porcine HDP genes such as p BD2, PG1-5, and p EP2 C were induced to different magnitudes by xanthohumol, deoxyshikonin, isorhapontigenin, and calycosin, although clear gene-and cel type-specific patterns of regulation were observed. Desirably, these four compounds had a minimum effect on the expression of several representative inflammatory cytokine genes. Furthermore, when used at HDP-inducing concentrations, these compounds showed no obvious direct antibacterial activity, but significantly augmented the antibacterial activity of 3 D4/31 macrophages(P 0.05) against both Gram-negative and Gram-positive bacteria.Conclusions: Our results indicate that these newly-identified natural HDP-inducing compounds have the potential to be developed as novel alternatives to antibiotics for prophylactic and therapeutic treatment of infectious diseases in livestock production.     

20%高效氯氰菊酯·辛硫磷微乳剂的研制

本文主要对20%高效氯氰菊酯·辛硫磷微乳剂的配方进行了研究,筛选出较优的表面活性剂、助表面活性剂,确定其最佳配方和制备方法,进而对20%高效氯氰菊酯·辛硫磷微乳剂质量指标和性能进行了测试、分析出了不同水质对其的影响,并对效益进行了分析。     

青藏高原表土磁化率空间分布特征及影响因素

土壤磁化率是古环境重建的常用代用指标，对表土磁化率与现代环境的关系研究有助于理解磁化率产生差异的原因。当前，区域尺度上土壤磁化率变化成因认知的缺乏限制了磁化率作为古环境重建重要代用指标的精准应用。本研究系统调查了青藏高原的254个样点表层(发生层A层)土样，测定土壤磁化率和其他土壤属性，结合母质、气候、地形和植被等数据，阐明青藏高原地区土壤磁化率空间变化特征，及其主要影响因素。结果表明：(1)不同母质类型之间，表层土壤磁化率(χlf)无显著差异，百分频率磁化率(χfd%)差异显著，黄土和砂页岩风化物>冰碛物和结晶盐风化物，其他母质类型之间无显著差异；不同土地利用之间，表层土壤χlf无显著差异，χfd%差异显著：森林和旱地>草地>荒地。(2)各因子对土壤磁化率影响，植被>理化性质>地形>母质。(3)空间分布上，东南部的χlf和χfd%均显示较高值。χlf空间分布呈由东南向西北降低的趋势，高值区位于东南部边缘，低值区位于腹地。χfd%空间分布规律与χlf相似，高值区位于东部偏南，低值区位于西部。此外，χlf和χfd%的空间分布规律与青藏高原植被分区相吻合。因此，磁化率能更好地指示植被空间分布。     

陇东地区旱地玉米套种柴胡高效栽培技术规程

玉米套种柴胡是陇东地区近年来试验研究推出的高效新技术，经济效益显著，为了使该技术的推广应用能发挥出最大效益。从范围、规范性引用文件、术语和定义、播前准备、播种、田间管理、病虫害防治、收获、残膜回收等方面规范了陇东地区旱地玉米套种柴胡高效栽培技术。     

天山雪莲rbcS基因启动子的克隆及序列分析

以天山雪莲(S.involucrata Kar.et Kir.)为材料,根据已获得的天山雪莲1,5-二磷酸核酮糖羧化/加氧酶小亚基基因组序列设计引物,采用热不对称交错PCR(TAIL-PCR)和高效TAIL-PCR(hiTAIL-PCR)扩增到rbcS基因5′上游启动子序列,长为1 668bp。用PlantCare和PLACE软件序列分析表明,该序列具有启动子的基本元件TATA-box、CA AT-box,包含多个胁迫诱导元件,如光诱导元件、赤霉素、低温诱导元件,昼夜节律调控元件等。构建pBI-PsikrbcS-GUS植物表达载体,并成功将其转化进入农杆菌。sikrbcS基因启动子的克隆与分析为进一步研究雪莲1,5-二磷酸核酮糖羧化/加氧酶小亚基基因的表达调控奠定了基础。     

谷子光敏色素家族基因的生物信息学及表达模式分析

光敏色素(PHY)是植物体重要的光感受器,在光形态建成中发挥重要作用.为挖掘新型模式植物谷子的光敏色素基因,通过BLAST从xiaomi基因组中共鉴定出4个SiPHYs,命名为SiPHY-1、SiPHY-2、SiPHY-3、SiPHY-4.利用生物信息学方法对SiPHYs的基因结构、理化性质、系统进化、启动子顺式作用元件和不同时期不同组织的表达谱进行分析,并采用RT-qPCR分析6个品种(系)在不同光周期下SiPHYs差异表达.结果表明,4个SiPHYs分布在8号和9号染色体上,除SiPHY-2外其余3个成员均为酸性亲水性蛋白;系统进化显示,SiPHY-1和SiPHY-2为PHYA亚族,SiPHY-3为PHYB亚族,SiPHY-4为PHYC亚族,且SiPHYs与狗尾草SvPHYs、玉米Zm-PHYs、高粱SbPHYs的亲缘关系近,与拟南芥AtPHYs亲缘关系较远;SiPHYs的顺式作用元件中光响应元件占比最多.表达谱分析结果显示,SiPHY-1可能与谷子的种子萌发有关,SiPHY-3可能与谷子形态建成有关,SiPHY-4可以调控谷子的抽穗开花期;进一步对6个品种(系)不同光周期下的差异表达显示,SiPHY-1在晋谷21和大同红谷中差异显著,SiPHY-3在大同红谷中差异显著,SiPHY-4在晋谷21、xiaomi、黄粟和xiaomi4中差异显著,而Si-PHY-2在不同光周期和不同材料中表达量均很低或不表达,说明SiPHY表达量受光周期和基因型的影响.