高效液相色谱法测定甲维盐和吡虫啉在番茄及其土壤中的残留量

为建立同时检测番茄及其土壤中甲维盐和吡虫啉残留的快速分析方法,采用丙酮/水（1∶1, V/V）提取样品,经硅胶和活性炭混合物层析柱净化,HPLC-UV 检测,对甲维盐和吡虫啉在番茄及其土壤中的残留进行了检测。结果表明：1）甲维盐和吡虫啉的混合标样添加量为0．05～1．0 mg/kg 时,甲维盐在番茄和土壤中的添加回收率分别为82．54％～86．60％和82．50％～96．21％,相对偏差分别为0．96％～3．30％和0．79％～3．93％;吡虫啉在番茄和土壤中的添加回收率分别为83．25％～94．20％和90．52％～98．39％,相对偏差分别为0．71％～1．78％和0．80％～3．24％,说明该方法的准确度和精密度均符合农药残留分析的要求,适合番茄及其土壤中甲维盐和吡虫啉的残留量检测。2）采用该方法对2013年番茄及其土壤中甲维盐、吡虫啉的残留状况进行检测表明,施药5 d 后的番茄甲维盐残留量为0．03～0．05 mg/kg,吡虫啉残留量为0．05～0．10 mg/kg;施药5 d 后,土壤中甲维盐的残留量为0．03～0．05 mg/kg,吡虫啉的残留量为0．04～0．08 mg/kg。两种农药在番茄和土壤中的残留量均未超过我国在番茄中最高残留限量标准的规定。     

甲基毒死蜱在甘蓝及土壤上的残留动态研究

采用气质联机（GC-MS）分析技术测定甲基毒死蜱在甘蓝及土壤上的残留消解动态和最终残留量。结果表明：喷施40％甲基毒死蜱乳油（有效成分720g／hm^2），甘蓝和土壤上的原始沉积量分别为3．50～5．82mg/kg和1．10～2．21mg/kg，半衰期为0．4～1．2d和3d，对甘蓝施药3次，最后1次施药距采收7d，采收时测得甘蓝上残留量为0．02～0．03mg/kg，说明甲基毒死蜱属于易降解农药。     

吡虫啉在白菜和土壤中的残留动态

采用Eclise XDB-C18色谱柱建立以乙腈-水为流动相的高效液相色谱条件,测定了吡虫啉在白菜及土壤中的残留动态.结果表明,吡虫啉在白菜和土壤中消解较快,其半衰期分别为2.02 d和4.31 d.吡虫啉在白菜和土壤中的最终残留量(21 d)分别为0.13 mg/kg和0.025 mg/kg,此值低于FAO规定的吡虫啉在十字花科蔬菜和土壤中的最低限量标准.     

油菜及土壤中乙草胺的残留研究

研究了乙草胺在油菜叶和土壤中的降解动态以及收获时油菜籽和土壤中的最终残留量。样品采用甲醇提取，弗罗里硅土净化，GC—ECD分析测定。方法的回收率为88．7％～116％，变异系数在5．9％～15％。方法的最低检出浓度为，油菜叶0．01mg／kg，油菜籽0．01mg／kg，土壤0．005mg／kg。乙草胺在油菜叶和土壤中的半衰期分别为1．3～1．5d和3．6—5．5d。在油菜苗期以有效成分810g/hm^2和1620g／hm^2施用乙草胺1次，乙草胺在收获的油菜籽中的最终残留量〈0．01mg／kg，土壤中的最终残留量最高为0．021mg／kg。乙草胺在油菜上使用是安全的。     

番茄及土壤中百菌清残留量的动态研究

采用气相色谱（GC-ECD）法研究了天津、吉林两地百菌清在番茄果实及土壤中残留量的动态变化。结果表明：在番茄果实上，百菌清的半衰期为3d，10-11d可降解90％以上；在土壤中，百菌清的半衰期为5～7d，16-24d可降解90％以上。最终残留试验的结果表明，按推荐剂量和高剂量分别施药3次和5次，于最后一次施药后的1、3、7d进行采收，番茄上百菌清的残留量分别为0～0．936mg／kg，符合国家标准GB2763的规定。     

吡虫啉在茶叶和茶园土壤中的残留研究

研究了吡虫啉在茶叶和茶园土壤中的残留分析方法及残留动态.样品采用二氯甲烷超声提取,中性氧化铝层析柱净化,反相液相色谱测定,方法的添加回收率鲜叶为75.8%～89.1%,土壤为81.8%～105.1%,变异系数分别为3.8%～5.5%和5.0%～5.9%,最低检测浓度鲜茶叶为0.01 mg/kg,土壤为0.003mg/kg.吡虫啉在鲜茶叶和土壤中的半衰期分别是1.9～2.2 d和3.7～2.8 d,在鲜茶叶中的降解速度快于在土壤中的降解速度.     

1.5％苦参·蛇床素水剂在番茄和土壤中的最终残留及消解动态

采用PSA固相萃取-高效液相色谱(HPLC)法,研究了露地和大棚条件下1.5%苦参·蛇床素水剂在番茄和土壤中的消解动态及最终残留,为番茄栽培中农药的安全使用提供参考。结果表明,2种栽培模式下苦参碱和蛇床子素的消解半衰期分别为5.18～6.70 d(番茄)、7.45～8.08 d(土壤)和1.70～1.99 d(番茄)、2.30～2.67 d(土壤)。距末次施药后1、3、7 d采样,苦参碱在番茄中的残留量为ND～0.427 4 mg/kg(露地)、0.010 2～0.522 8 mg/kg(大棚);蛇床子素在番茄中的残留量为ND～0.388 7 mg/kg(露地)、ND～0.395 2 mg/kg(大棚)。苦参碱和蛇床子素均属易降解农药,二者在大棚番茄和土壤中的消解半衰期均长于其在露地。在相同施药剂量、次数和采收间隔期下,除个别情况外,苦参碱和蛇床子素在大棚番茄和土壤中的最终残留量均高于其在露地的相应值。     

25 %施保克乳油在芒果防腐保鲜贮藏后残留消解动态分析

气相色谱分析25％施保克乳油在芒果防腐保鲜贮藏后的残留消解动态，方法回收率为90．6％～95．3％。施保克处理芒果后果皮中的原始沉积量：广西为4．1126-4．8267mg／kg，广东为3．8218-4．4563mg／kg；半衰期：广西13．0～13．5d，广东为14d，经30d后两地的分解率均大于92．68％。最终残留量，以最高浓度2000mg／kg浸果。贮藏期10～30d，果肉中的残留：广西小于0．0563mg／kg，广东小于0．0623mg／kg；全果中残留，广西0．0699-0．6414mg／kg，广东0．0607-0．5847mg／kg。经10d后广西、广东两地的全果残留分别为0．5752-0．6414mg／k和0．5847-0．5858mg／kg。按FAO／WHO规定，施保克在芒果中MRL值为2mg／kg，经两年两地试验其残留量均低于此值。施保克25％乳油浸芒果贮藏保鲜，其安全间隔期在10d以上是安全的。     

烯酰吗啉在土壤及番茄中残留量的气相色谱分析

为明确烯酰吗啉在土壤及番茄中的残留状况,建立了气相色谱测定土壤和番茄中烯酰吗啉残留量的分析方法。样品用乙腈振荡提取,再用乙酸乙酯萃取,经中性氧化铝层析柱净化后,通过火焰离子化检测器检测,外标法定量。结果表明：在0．5～15mg／L范围内,烯酰吗啉的峰面积与其质量浓度间呈良好的线性关系,相关系数为0．9996。在添加水平为0．5～5．0mg／kg范围内,土壤和番茄中烯酰吗啉平均回收率分别为85．4％～92．7％、89．8％-99．3％,相对标准偏差分别为1．61％～6．59％和1．62％～2．32％。经检测,烯酰吗啉在番茄上的残留量未超过韩国最高残留限量标准。     

腐霉利在番茄上的残留分析

为了评价腐霉利在番茄上的残留状况。指导腐霉利的科学合理使用,本试验选择50％腐霉利可湿性粉剂推荐剂量500．0、750．0g／hm2（有效成分）,连续施药2～3次,间隔5d,最后一次施药3、7、10d后采集番茄样品进行残留检测。结果表明,腐霉利在番茄上的残留量为0．075-0．256mg／kg,小于GB2763—2012规定的农药最高残留量（2mg／kg）：结合番茄成熟期长,建议腐霉利在番茄上的安全间隔期为10d。     

Web2.0,以个人为中心的互联网时代的到来

本文介绍了Web2．0的知识和背景，对Web2．0出现的基础以及典型技术和应用作了阐述，同时对其作出了前景展望。     

市级综合气象信息分析与管理系统的设计与实现

以抚顺地区3个国家基本站50余年气象资料为依托，采用Microsoft Excel工作表实现由气候和农业气候2部分构成的气象与农业综合信息处理系统的基本思路、方法、内容、用途和使用情况。为了实现气候分析及应用的科学化、客观化、系统化、规范化、程序化及连续化的业务目标，按业务流程设计与实现的，包括资料处理、气候趋势模拟、气候预测、气候鉴定、季节性信息化处理、农作物产量预报、气候生产潜力分析等一系列内容在内的系统建设。关键是解决了大量的计算问题，建立了区域性通用模式。     

Multi-variable grey model (MGM (1,n,q)) based on genetic algorithm and its application in urban water consumption

Urban water consumption has some characteristics of grey because it is influenced by economy, population, standard of living and so on. The multi-variable grey model （MGM（1,n））, as the expansion and complement of GM（1,1） model, reveals the relationship between restriction and stimulation among variables, and the genetic algorithm has the whole optimal and parallel characteristics. In this paper, the parameter q of MGM（1,n） model was optimized, and a multi-variable grey model （MGM（1 ,n,q）） was built by using the genetic algorithm. The model was validated by examining the urban water consumption from 1990 to 2003 in Dalian City. The result indicated that the multi-variable grey model （MGM（1,n,q）） based on genetic algorithm was better than MGM（1,n） model, and the MGM（1,n） model was better than MGM（1,1） model.     

Molecular detection of virulence genes in Campylobacter species isolated from livestock production systems in South Africa

Campylobacter species are a major cause of foodborne bacterial infections in both developed and developing countries worldwide. Campylobacter jejuni is responsible for the majority of infections. This study was conducted to identify virulenceassociated genes in Campylobacter species isolated from livestock production systems in South Africa. A total of 250 fecal samples consisting of cattle(n=50), chickens(n=50), goats(n=50), sheep(n=50) and pigs(n=50) were randomly collected from livestock in Eastern Cape and KwaZulu-Natal provinces of South Africa between April and October 2018. The samples were analyzed for the presence of virulence genes in Campylobacter species using molecular PCR-based methods. It was found that 77 and 23% of Campylobacter jejuni and Campylobacter coli respectively were isolated from all the livestock samples. There were positive significant(P0.05) correlations amongst all the virulence genes that were investigated. Chisquare and Fisher's exact tests were implemented to test for the effect of livestock species on the presence or absence of virulence genes. The study demonstrated that most of livestock species can potentially cause zoonotic infections and food poisoning due to the high prevalence of Campylobacter. The high prevalence of virulence genes highlights the significance of Campylobacter in livestock production systems in South Africa. This requires the implementation of one-health approaches to reduce the impact of foodborne and zoonotic diseases for the welfare of human and animal health.     

不同施肥水平对木薯氮磷钾养分积累、分配及其产量的影响

 【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异，探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料，采用“3414”方案，在粤北翁源进行大田试验。试验共设14个处理。【结果】施肥处理的氮素主要分配到地上部，不施肥处理的氮素则主要分配到根部；不同施肥处理的磷素均主要分配到地上部；不施肥处理和不施钾处理的钾素主要分配到根部，不施氮处理的钾素在根、冠间分配较均衡。在木薯不同生长阶段，植株氮磷钾含量均呈下降趋势，但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理。处理N2P2K2的氮、磷、钾含量和积累量在各生育期均为最大，不施肥处理（N0P0K0）的氮、磷、钾含量和积累量在各生育期均为最小（P＜0.05）。产量最高的是N2P3K2处理，为22 694.06 kg·hm-2，其次是N2P2K2处理，为21 417.87 kg·hm-2。【结论】木薯产量、氮磷钾养分积累及其在根冠间的分配，对施肥水平高度敏感, 适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量，又可以提高产量。在粤北坡岗地木薯生产中，氮素最重要，在氮素得到满足的条件下，磷素较钾素更重要。在本试验条件下，氮磷钾养分最佳用量为358.80 kgN·hm-2、89.10 kg P2O5·hm-2和187.50 kg K2O·hm-2。     

红苕饲粮中添加铜和/或喹乙醇对猪生产性能及某些血液生化指标的影响

选体重约38公斤的长白(♂)×成华(♀)杂交猪20头,随机分为四组,饲予四种不同的饲粮,研究饲粮中添加铜和/或喹乙醇对猪生产性能和某些血液生化指标的影响。结果表明:基础组、加铜组、加喹乙醇组和两者同时加组全期日增重分别为674、761、796、678克,日采食量分别为2.50、2.65、2.74、2.40公斤,饲料利用率分别为3.73、3.49,3.44、3.54,添加铜和/或喹乙醇对试验第65天血清铜兰蛋白、尿素氨及屠宰率、背膘厚和眼肌面积无显著影响(p>0.05);添加铜使65天血清碱性碱酸酶活性极显著增高(p<0.01),添加喹乙醇有使之升高的趋势,两者同时添加时,碱性酸磷酶活性降低。     

Current progress on genetic interactions of rice with rice blast and sheath blight fungi

Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens of rice resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.     

Virus Location and Lymphocyte Apoptosis in Lymph Nodes of Piglets Infected with PCV-2

The present study has been performed to understand the location of the virus, type of apoptotic cells, and their relation to lymph nodes of piglets infected with porcine circovirus type Ⅱ （PCV-2）. Nine 32-day-old conventional piglets free of infection with PCV-2 were used, and distributed into three groups： control group （n = 3）, piglets inoculated with PCV-2 alone （PCV-2, n = 3）, and PCV-2 inoculated and KLH immunostimulated group （PCV-2 ＋ KLH, n = 3）. Superficial inguinal lymph nodes from all piglets were collected for histological examination after 32 days postinoculation, and immunohistochemistry for PCV-2 detection. Location of apoptotic cells was detected with TdT-mediated dUTP nick end labeling （TUNEL） and cell cycle, and the apoptotic rates were measured by flow cytometry. The characteristic histopathological lesions of the piglets in PCV-2 and PCV-2 ＋ KLH were lymphocyte depletions in the cortex and paracortex of the lymph nodes, epithelioid-like macrophage infiltration, and intracytoplasmic inclusion bodies presented in epithelioid-like macrophages. PCV-2 was mainly found in epithelioid-like macrophages by immunohistochemistry. In the lymph nodes, lymphocytes presented higher apoptotic rates in the cortex by TUNEL, special B-cell areas, and similar apoptotic cells were found in this compartment in the control. The apoptotic rates of the lymph nodes were 0.41, 3.34, and 4.88% in the control, PCV-2, and PCV-2 ＋ KLH groups by flow cytometry, respectively. The apoptotic rates of lymph nodes for PCV-2 and PCV-2 ＋ KLH piglets were significantly higher than those for the control group （P〈0.05 and P〈0.01）. The proliferation index （PI） was 0.17_＋0.01, 0.12_＋0.01 and 0.12_＋0.04 in the control, PCV-2, and PCV-2 ＋ KLH group, the PI of the control group was higher than that of the other groups, but without the statistical difference. PCV-2 can induce lymphocyte depletion in lymph nodes of piglets by blocking cell proliferation and promoting apoptosis. This is one o     

锌对镉·汞复合污染下豌豆幼苗生长的影响

以豌豆为试验材料,采用水培方法研究了锌对镉、汞复合污染下的豌豆种子萌发与生长的影响。结果显示,锌浓度≤100.0 mg/L时促进豌豆种子的萌发,锌浓度为200.0和300.0 mg/L时抑制豌豆种子的萌发。当镉、汞的浓度为3.0 mg/L时,100.0 mg/L锌的解毒效应最明显,表现为能够促进镉、汞胁迫下豌豆种子萌发和幼苗生长,降低豌豆幼苗根尖细胞畸变率,提高豌豆幼苗的叶绿素含量及过氧化物酶活性;但当锌浓度≥200.0 mg/L时,与镉、汞协同迫害豌豆幼苗的生长。     

仙人掌超氧化物歧化酶提取与纯化研究

以仙人掌为试验材料,采用硫酸铵分级沉淀法得到超氧化物歧化酶（Superoxide Dismutase,SOD）粗酶液。然后用Sephadex（葡聚糖凝胶）G-75层析柱层析对粗酶液进行进一步纯化,最后用邻苯三酚法测定酶活力,并对酶活力主要影响因素（包括pH值、温度、抑制剂）进行了研究。结果显示仙人掌SOD酶比活力为751.56U.mg-1。pH值为7.5~8.5时酶活力最大,稳定性也好。温度维持在25~30℃时酶活力最高。由于过氧化氢和氰化钾均能使仙人掌SOD的酶活力显著下降,因而可以初步判断从仙人掌中提取到的SOD是Cu.Zn-SOD。