Serological investigations of peste des petits ruminants among cattle in the Sudan

Tropical Animal Health and Production - During 2015 and 2016, from five different States of the Sudan, a total of 1000 cattle sera were purposively collected from many herds of apparently healthy...     

基质分散固相萃取-QuEChERS耦合HPLC法测定棉花叶片中吡虫啉及其相关代谢物

建立了QuEChERS前处理的棉花叶片中吡虫啉及其代谢物含量的高效液相色谱（HPLC）分析方法。在QuEChERS前处理方法的基础上,确定了乙腈作为提取剂,盐析材料为1.00 g氯化钠、4.00 g无水硫酸镁、0.50 g柠檬酸二钠和1.00 g柠檬酸钠,净化材料为25 mg的N-丙基乙二胺（PSA）,在2%乙腈-甲醇∶水=3∶7条件下HPLC法进行定量测定。结果表明：棉花叶片中的吡虫啉及其4种代谢物吡虫啉脲、烯式吡虫啉、吡虫啉胍和6-氯烟酸的平均加标回收率为92.84%~110.90%,相对标准偏差（RSD）在0.15%~6.99%之间,检出限（LOD）分别为0.0044、0.042、0.0011、0.091 mg·kg^-1和0.0066 mg·kg^-1,定量限（LOQ）分别为0.015、0.19、0.0059、0.036 mg·kg^-1和0.028 mg·kg^-1。该分析方法前处理简便、快速、准确,可为棉花叶片中吡虫啉及其代谢物残留的测定提供参考。     

Identification of spider mites from Moringa oleifera using molecular techniques

Moringa oleifera plants are highly nutritious and had since attracted much attention for serving as alternative crops in marginal communities in developing countries. Generally, claims abound that moringa plants are pest-free, with ISO precluding the use of unregistered products. However, moringa seedlings are often attacked by an unidentified aggressive spider mite (Tetranychus species) under humid greenhouse conditions, resulting in outright withering of seedlings, with the potential of decimating an entire moringa orchard. Thus, molecular techniques were used to identify the spider mites on moringa to the species level in order to allow for the development of management strategies. Spider mite strains from moringa and adjacent sweet stem sorghum (Sorghum bicolor) seedlings were collected and mitochondrial cytochrome c oxidase subunit I (COI) gene used for molecular identification. DNA sequences were generated and subjected to Blastn search on the National Center for Biotechnology Information database, with the neighbour-joining method used to establish the relative closeness of the test strains to Tetranychus species. Phylogenetically, the test spider mite was, Tetranychus urticae, closely related to T. urticae strains in Lineage I, which is dominated by the Mediterranean haplotypes. The derived information would allow for the development of appropriate management strategies of this pest on moringa seedlings using various products for eventual registration.     

重金属单一污染对龙须草生长与生理生化特性的影响

试验研究了不同处理水平下Cd、Pb、Cu、Zn、As单一污染对龙须草生长和生理生化特性的影响。结果表明:龙须草地下部对重金属的抗性大干地上部,种植龙须草的污染土壤中Cd、Pb、Cu的土壤临界值可分别设定为10mg／kg、300mg／kg和100mg／kg;龙须草叶绿素含量随重金属处理浓度的增加呈先升后降趋势,但其总叶绿素含量和叶绿素a／b值均低于对照;龙须草SOD活性随Zn、As单一污染处理浓度的增加呈先升后降趋势,而随其他3种重金属处理浓度的增加呈下降趋势;龙须草CAT和POD的活性随As处理浓度的增加呈上升趋势,而随其他4种重金属处理浓度的增加呈先升后降趋势。     

Solar wind outflow and the chromospheric magnetic network

Observations of outflow velocities in coronal holes (regions of open coronal magnetic field) have recently been obtained with the Solar and Heliospheric Observatory (SOHO) spacecraft. Velocity maps of Ne7+ from its bright resonance line at 770 angstroms, formed at the base of the corona, show a relationship between outflow velocity and chromospheric magnetic network structure, suggesting that the solar wind is rooted at its base to this structure, emanating from localized regions along boundaries and boundary intersections of magnetic network cells. This apparent relation to the chromospheric magnetic network and the relatively large outflow velocity signatures will improve understanding of the complex structure and dynamics at the base of the corona and the source region of the solar wind.     

玉米铁微营养生物有效性与生物强化的研究进展

综述了玉米子粒中铁的分析方法、生物有效性及其影响因素、铁生物强化的传统与分子育种途径的研究进展,并对HarvestPlus项目与组织作了概略的介绍。