Comparison of an enzyme-linked immunospecific assay (ELISA) with the cold complement fixation test for the serodiagnosis of Brucella ovis infection

An enzyme-linked immunospecific assay (ELISA) for the serodiagnosis of Brucella ovis infection in sheep is described and compared with the cold complement fixation (CF) test. ELISA was performed in microtiter plates, using horse-radish peroxidase conjugated to anti-normal sheep serum globulins, and hydrogen peroxide plus o-phenylenediamine as substrate. A heated, cell-free B. ovis extract was used as antigen in both tests. ELISA was easier to perform, distinguished better between positive and negative sera, and did not need heat-inactivated sera.     

宁南山区旱地紫花苜蓿土壤水分及产量动态研究

对宁南山区旱地紫花苜蓿土壤水分及产量动态进行了研究。结果表明,随苜蓿草龄的延长,土壤深层水分亏缺严重草地底层与中层对表层水分具有明显的补偿作用;伏秋降对水冬前土壤蓄水亦有重要作用;产量随草延长呈中间高两头低的态热,６－８年以后草地须及时更新。     

水稻田间育秧水肥药变量喷灌装置设计与试验

为解决南方水稻工厂化田间育秧水肥药人工管理作业中存在的灌溉均匀性差、化肥和农药浪费以及劳动强度大等问题,该研究设计了一种水稻田间育秧水肥药变量喷灌装置,阐述了水肥药变量喷灌装置总体结构和工作原理,进行了关键部件设计与试验;以可编程逻辑控制器（programmable logic controller,PLC）为控制核心,构建了注肥量在线调控及整机变量喷灌控制系统。采用Box-Behnken试验设计方法,对装置喷灌均匀性与主要影响因素进行试验研究,应用单目标优化方法对喷灌关键参数进行优化,并通过验证试验,得到最优参数组合为：干管入口水压0.20 MPa、球阀开度90°、喷头喷角80°,此时装置的喷灌均匀性为92.69%;构建了氯化钾肥液质量浓度与电导率（electrical conductance,EC）值的线性模型,开展了装置变量灌溉施肥性能试验,3种喷灌等级下各作业区的肥液EC值分别为1.65、1.66和1.68 mS/cm,平均喷灌强度分别为900.85、1092.04和1263.67 mm/h,施肥均匀系数分别为85.21%、87.86%和91.62%。采用水肥药变量喷灌装置开展水稻育秧田间管理试验,华航51常规稻和广8优165杂交稻的秧苗长势均匀度均高于95%,成毯性良好,各项素质指标满足机插作业要求。所设计的水肥药变量喷灌装置能够满足水稻田间育秧水肥药变量喷灌作业要求,对提高水稻工厂化田间育秧机械化水平、保证秧苗质量具有实际应用价值。     

Dihydroartemisinin enhances radiotherapy efficiency in H22 cell tumor-bearing mice by regulating PI3K/AKT signaling pathway

AIM To study the effect of dihydroartemisinin （DHA） on the radiotherapy efficiency in hepatocellular carcinoma H22 cell tumor-bearing mice and the role of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （AKT） signaling pathway in this process. METHODS A model of H22 cell tumor-bearing mice was established. The mice was divided into model group, single radiotherapy group, 5-fluorouracil （5-FU） group, and low-, medium- and high-dose DHA groups. The body weight and tumor volume in each group were measured every other day. At the end of administration, blood was collected from the tail of the mice and the animals were killed by neck removal immediately. The synergistic effect of DHA on radiotherapy was determined, and tumor growth inhibitory rate was calculated. The degree of lymphocyte transformation and natural killer （NK） cell activity were measured by MTT, the serum levels of interleukin-2 （IL-2） and IL-4 were measured by ELISA, and the protein levels of PI3K, AKT and p-AKT were determined by Western blot. RESULTS The H22 cell tumor-bearing mouse model was successfully constructed. Compared with model group, the TGT₃ （tumor growth time to reach 3 times of volume） of single radiotherapy group was remarkably increased （P<0.05）, while tumor weight, lymphocyte transformation degree, NK cell activity, IL-2 and IL-4 levels, PI3K protein level and AKT phosphorylation level were remarkably decreased （P<0.05）. Compared with single radiotherapy group, TGT₃, EF （enhancement factor）, tumor inhibitory rate, lymphocyte transformation degree, NK cell activity, IL-2 level and IL-4 level were increased with the increase in DHA dose （P<0.05）, and the PI3K protein level and AKT phosphorylation level were decreased （P<0.05）. CONCLUSION DHA may enhance the immunity of tumor-bearing mice by inhibiting the activity of PI3K/AKT signaling pathway, thereby enhancing the efficacy of radiotherapy.     

Glugea heraldi n. sp. (Microsporida, Glugeidae) from the seahorse Hippocampus erectus Perry

Abstract. A new species of Microsporida, Glugea heraldi , is described from the seahorse Hippocampus erectus . Measurements of fixed spores and notes on the histopathology of parasitized tissue are given.     

紫甘薯多酚氧化酶性质探讨

甘薯是世界上一种重要的粮食和能源作物,由于加工过程中其组织中的多酚氧化酶易催化多酚类物质氧化成黑色素,严重影响了其加工品质.以济薯18为材料,研究了pH值、温度、底物浓度等对其多酚氧化酶(PPO)活性的影响.结果表明:紫甘薯济薯18中PPO活性在360 am处最大,其最适反应时间为11 min,最适pH值6.5,最适温...     

新疆野生樱桃李SSR体系的建立及应用

为建立适宜新疆野生樱桃李的SSR分子标记技术体系,通过对PCR反应程序、反应体系(DNA模板量、引物浓度、Mg2+浓度、dNTP浓度、Taq酶用量)以及退火温度进行了探索,建立了适宜野生樱桃李的SSR-PCR反应体系。结果表明:在25μL反应体系中,Mg2+1.0 mmol/L、引物0.5μmol/L、dNTPs 0.20 mmol/L、TaqDNA聚合酶1.0 U、模板DNA 30 ng、退火温度为60℃。SSR扩增程序:94℃预变性5 min,35个循环(94℃30 s,60℃1 min,72℃1 min),72℃延伸10 min,可筛选出稳定性好、多态性高的SSR引物。     

防治烟草根黑腐病拮抗芽孢菌株的筛选

由基生根串珠霉菌(Thielaviopsis basicola)引起的烟草根黑腐病是烟草生产上重要根部真菌病害,近年在我国烟草种植区有加重危害的趋势,目前防治措施主要依赖化学药剂,给卷烟卫生带来一系列问题[1].探索该病生物防治途径,克服农药残留和病原菌抗药性十分重要.芽孢杆菌是土壤和植物微生态区系的优势生物种群,具有优良生防特性[2],采用芽孢杆菌作为烟草根黑腐病生防因子尚未见报道.本研究从烟草根际土壤中分离筛选对烟草根黑腐病病菌有较强拮抗作用的芽孢菌株,研究其抑菌活性、控病作用及其分类学地位.     

芽胞杆菌CQBS03抑菌蛋白TasA基因的克隆及原核表达

为了探讨柑桔溃疡病生防菌芽胞杆菌Bacillus CQBS03菌株TasA基因的功能,采用PCR方法从CQBS03基因组DNA中扩增出编码TasA基因的全长DNA序列,并构建pEASY-E1/TasA原核表达载体,经大肠杆菌Escherichia coli表达获得TasA基因的融合表达蛋白,纸碟法检验融合蛋白对柑桔溃疡病菌Xanthomonas citri citri的抑制作用。结果显示,CQBS03菌株的TasA基因包含1个786 bp的完整开放阅读框（GenBank登录号为JQ309841）,编码261个氨基酸残基;该序列与来源于解淀粉芽胞杆菌B.amyloliquefaciens的1个已知同源TasA基因序列FJ713580的相似性达99.75%。原核表达产物经SDS-PAGE分析,检测到约31 kD的融合蛋白;纯化后的融合蛋白对柑桔溃疡病菌有明显的抑制作用,72 h后抑菌圈直径达11.5 mm。研究表明TasA基因是生防菌芽胞杆菌CQBS03抑制柑桔溃疡病菌的功能基因之一,并且该基因对原核表达宿主没有抑制作用,具有较好的开发利用前景。     

辣椒白粉病防治技术初探

采用引进新农药拿敌稳75%WG(水分散粒剂)开展其不同浓度防治辣椒白粉病试验,探讨辣椒白粉病最佳防治技术。试验结果表明:拿敌稳75%WG3000倍液防治辣椒白粉病,防效达95.27%;增产效果最明显,其平均株高、鲜株重、百果干重、每株总果数、单产、商品率均高于其它处理和当地对照药剂;经济效益比为1∶13.41。