狐狸传染性脑炎中和试验监测方法的建立和应用

本研究建立了狐狸传染性脑炎中和试验方法,采用该方法对疫苗免疫狐狸进行抗体水平动态监测。结果表明:该方法特异性强,重复性好,适用于狐狸传染性脑炎活疫苗免疫效果评价。     

丙酸钙的生产工艺研究

综述了高效饲料防腐剂丙酸钙的制备方法,确定了以鸡蛋壳为原料,中和法制备丙酸钙的最佳工艺条件:反应温度为50℃,丙酸过量程度为50%,反应时间为45min,经过滤、浓缩,烘干得粉末状白色无水丙酸钙晶体,其产率可达90%以上。     

中和温度对鸡新城疫、鸡传染性支气管炎二联活疫苗中鸡传染性支气管炎病毒含量影响的研究

采用分别测定每羽份疫苗成品和每0．1mL半成品胚液鸡胚半数感染量(EID50)的方法探讨了中和温度对鸡新城疫、鸡传染性支气管炎二联活疫苗中鸡传染性支气管炎病毒含量的影响。结果显示，中和温度对该二联活疫苗中鸡传染性支气管炎病毒的EID50有显著的影响。测定病毒含量时，中和条件以中和温度控制在20℃、中和时间45～60min较为合适。     

标准鸭肝炎I型血清对鸭肝炎野毒株的免疫保护试验

为探讨珠江三角洲及其附近地区鸭肝炎免疫失败的原因，对从该地区分离到的鸭肝炎野毒SN株等6个毒株在7日龄雏鸭、10日龄鸭胚上作免疫保护试验、交叉中和试验。试验结果表明，标准鸭肝炎I型（DH－1）血清对部分野毒株（SN株、Z株、SF株）的免疫保护指数较低，明显低于相应野毒株血清的保护指数，表明该校区部分鸭肝炎野毒的原性已发生改变。这一免疫保护试验结论得到了交叉中和试验结果的支持。根据试验结果，采取若干有代表性鸭肝炎野毒性与标准DH－I型毒株，制备鸭肝炎高名血清或高免卵黄抗体用于临床免疫防治，并注意排除一些其他因素的干扰，使临床免疫保护率达到96％。     

二次中和法制取脱皮双低菜籽复合氨基酸工艺研究

为得到高质量的菜籽复合氨基酸,以脱皮菜籽粕为原料,研究了硫酸水解制备复合氨基酸的新工艺-二次中和法,解决了氨基酸脱色和副产品植酸的利用问题.水解的最佳工艺参数为:硫酸浓度12mol/L,菜籽粕与硫酸溶液的比例为1:6,水解18h;用Ca(OH)2乳液中和,第一次中和和脱色的最佳pH值为2～4,第二次中和的最佳pH值为6.5～7.0,第二次中和可获得副产品植酸钙.中和后的溶液经减压浓缩,喷雾干燥,制得复合氨基酸产品.复合氨基酸得率35.19%,植酸钙得率11.73%,复合氨基酸产品中未检出OZT和ITC.     

猪流行性腹泻病毒3种抗原卵黄抗体的制备

【目的】探讨猪流行性腹泻病毒(PEDV)3种不同抗原制备的卵黄抗体对PEDV的中和能力,为抗猪流行性腹泻卵黄抗体的制备提供新的方法和理论基础。【方法】根据PEDV S糖蛋白基因设计引物扩增PEDVS534基因(636~789位氨基酸)和PEDV COE基因(499~638位氨基酸),并构建原核表达质粒pET32a-PEDV S534和pET32a-COE,分别转化表达菌株BL21(DE3)进行诱导表达。以原核表达的PEDV S534蛋白、COE蛋白以及PEDV灭活病毒为抗原,分别免疫产蛋鸡并制备卵黄抗体,通过病毒中和试验评价各卵黄抗体的中和效力。【结果】成功表达了PEDV S534蛋白和COE蛋白,Western-Blotting分析显示,2种蛋白均具有很好的免疫原性;制备的3种特异性卵黄抗体均具有一定的病毒中和能力,PEDV S534蛋白特异性卵黄抗体的中和效价为1∶12,COE蛋白特异性卵黄抗体的中和效价为1∶25,而PEDV灭活病毒的卵黄抗体中和效价达到1∶120。【结论】PEDV灭活病毒的中和能力最强,其次为COE蛋白特异性卵黄抗体,PEDV S534卵黄抗体的中和能力较弱。     

一株新分离犬细小病毒灭活疫苗的制备及免疫效果研究

JL0911株犬细小病毒是由军事兽医研究所流行病与病毒病防控技术实验室分离得到的一株新型犬细小病毒,其主要抗原位点上的氨基酸序列较国内先前分离到的其他株有较大差异,不能被归入目前已有的CPV-2a、CPV-2b、CPV-2c三个类型。本研究旨在利用JL0911株犬细小病毒研制灭活疫苗,并评价其免疫原性。试验采用10^5.5 TCID₅₀/mL的犬细小病毒JL0911,以甲醛灭活后,加入1/4体积的纳米佐剂,制备了犬细小病毒灭活疫苗。取1.5 mL上述疫苗,通过肌肉注射免疫普通家犬,免疫前后不同时间均采集血清,在F81细胞系上测定犬细小病毒的中和抗体。结果显示,免疫后14 d,试验犬血中细小病毒中和抗体效价较免疫前有显著提高,最高可由0提高至2⁹,表明本试验分离的JL0911株犬细小病毒具有生产犬细小病毒灭活疫苗的潜在价值。     

Sulfated Galactan from Palisada flagellifera Inhibits Toxic Effects of Lachesis muta Snake Venom

In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse the evolution of all the toxic effects is performed by injection of antivenom. However, such therapy does not effectively neutralize tissue damage or any other local effect, since in most cases victims delay seeking appropriate medical care. In this way, alternative therapies are in demand, and molecules from natural sources have been exhaustively tested. In this paper, we analyzed the inhibitory effect of a sulfated galactan obtained from the red seaweed Palisada flagellifera against some toxic activities of L. muta venom. Incubation of sulfated galactan with venom resulted in inhibition of hemolysis, coagulation, proteolysis, edema and hemorrhage. Neutralization of hemorrhage was also observed when the galactan was administered after or before the venom injection; thus mimicking a real in vivo situation. Moreover, the galactan blocked the edema caused by a phospholipase A₂ isolated from the same venom. Therefore, the galactan from P. flagellifera may represent a promising tool to treat envenomation by L. muta as a coadjuvant for the conventional antivenom.     

Effect of wood ash fertilization on soil chemical properties and stand nutrient status and growth of some coniferous stands in Finland

The effects of wood ash or wood ash plus nitrogen (N) fertilization on soil chemical properties, needle nutrient concentrations and tree growth were studied in five coniferous stands, aged 31–75 yrs, after 5 and 10 yrs. In each experiment 3 t ha^?1 of loose wood ash was applied to three replicated plots (30×30 m). In three of the experiments 120–150 kg N ha^?1 was applied together with the same wood ash (WAN). These three experiments also included a stand-specific fertilization (SSF) treatment, which consisted of 120, 150 or 180 kg N ha^?1. Five years after wood ash or WAN application the pH increase in the humus layer was 1–1.7 pH-units and in the 0–5 cm mineral soil layer 0.3–0.4 pH-units. The increase was approximately the same 10 yrs after application, and was also associated with an increase in pH in the 5–10 cm mineral soil layer. Wood ash or WAN significantly increased both the total and extractable calcium and magnesium concentrations in the humus layer on all the sites. Wood ash or WAN had an increasing effect on the boron concentrations, but a decreasing effect on the manganese concentrations in the needles. Wood ash had no significant effect on the volume growth. The trees on the WAN plots grew as well as or slightly better than those on the SSF plots.     

基于气象要素的冬小麦分期播种对比分析

本文利用山东省泰安农业气象试验站2019-2020与2020-2021年冬小麦分期播种试验实测数据以及同期气象观测资料,分析不同播期气象条件对冬小麦生长及产量的影响。结果表明：（1）对于泰科麦31品种小麦,日照时数在冬小麦出苗-开花阶段起重要作用,发育期天数与日照时数呈显著正相关,即在冬小麦出苗后日照越充足,苗情越好;抽穗期后日照条件差,对冬小麦灌浆速率起限制作用。（2）越冬过程的开始主要受日最高气温及其持续时间的影响,越冬期持续时间的长短则受日最低气温及其持续时间的影响。（3）适量的降水对冬小麦灌浆速率起促进作用。（4）各播期处理的冬小麦灌浆过程均符合 Logistic 生长规律,灌浆速率与各气象要素之间关系在不同播期的表现不同。（5）冬小麦千粒重受前期生长状况与越冬期积温、负积温影响,冬小麦越冬期低温持续时间短有利于冬小麦产量的提高;千粒重与日照时数呈显著正相关。