小菜蛾为害不同生育期秋甘蓝对产量的影响及经济阈值研究

采用笼罩法测定了小菜蛾在秋甘蓝不同生育期为害造成的产量损失,建立了产量损失率与小菜蛾虫口密度的回归关系式。结果表明,在秋甘蓝苗期、莲座期、结球始期和结球中后期秋甘蓝损失率(y)与小菜蛾虫口密度(x)关系式分别为:y=9.480 6x-2.586 2,y=3.621 8x-0.790 2,y=-0.210 7x2+6.698 1x-1.906 5和y=0.081 1x2-0.147 9x+0.405 4。根据经济阈值模型,秋甘蓝不同生育阶段的小菜蛾幼虫经济阈值分别为苗期0.54头/株,莲座期0.91头/株,结球始期0.67头/株,结球中后期6.08头/株。该研究为秋甘蓝小菜蛾的防治策略和经济阈值的确定提供了科学依据。     

草地贪夜蛾核型多角体病毒对草地贪夜蛾的毒力及其侵染特征

为明确草地贪夜蛾核型多角体病毒（Spodoptera frugiperda multiple nucleopolyhedrovirus,SfMNPV）对草地贪夜蛾Spodoptera frugiperda 的毒力及其体内外侵染特性,于室内测定SfMNPV对草地贪夜蛾的毒力,采用苏木精-伊红（hematoxylin-eosin,HE）染色分析SfMNPV侵染后草地贪夜蛾的组织病理学特征,通过实时荧光定量PCR（real-time fluorescence quantitative PCR,qPCR）技术分析SfMNPV在草地贪夜蛾体内和Sf9细胞系中的复制特征。结果表明,SfMNPV对草地贪夜蛾2龄幼虫的LC₅₀和LT₅₀分别为7.39×10⁵ OBs/mL和3.82 d;SfMNPV可侵染草地贪夜蛾幼虫的真皮、气管、脂肪体和中肠等组织,未侵染肌肉组织;SfMNPV侵染96 h后草地贪夜蛾体内SfMNPV基因组拷贝数最大,为3.91×10⁶ 拷贝数/ng,SfMNPV侵染96 h后Sf9细胞培养上清液中SfMNPV基因组拷贝数最大,为2.08×10⁷ 拷贝数/mL。     

蒋白纹枯病菌菌丝融合群及其致病性测定

菌丝融合型测定结果表明，32个茭白纹枯病菌菌株隶属于两个菌丝融合群：30个属AG1群，占测定菌株的93．95％，其中AG1-IA、AG1－IC两亚群菌株依次为24与6，有两菌株为AG4，占6．25％。显然，AG1－IA为优势融合群，占测定菌株的75％。融合群致病性测定结果表明，AG1－IA致病性强，AG1－IC弱，AG4基本不致病。茭白与水稻两种纹枯病菌交互接种，其发病基本一致。由此，作者认为这两种纹枯病菌为同一病原物，或者说茭白、水稻是同一病原物的两个寄主植物。     

宁夏灌区玉米平播密植模式下的农田蛾类多样性研究

为了解宁夏灌区玉米平播密植模式下田间蛾类昆虫的组成及发生时序动态,对灌区玉米田进行灯诱监测,获得蛾类昆虫标本10科42种。明确了该种植模式下蛾类以夜蛾科(Noctuidae)和草螟科(Crambidae)昆虫为主要类群,优势种为旋幽夜蛾(Discestra trifolii)、草地螟(Loxostege sticticalis)、亚洲玉米螟(Ostrinia furnacalis)和小地老虎(Agrotis ypsilon)。刀夜蛾(Simyra nervosa)为宁夏新记录的种类。8月下旬蛾类群落多样性水平最高,Shannon-Wiener指数、均匀度指数、丰富度指数及优势度指数依次为2.509 8、0.868 3、4.492 4、0.089 9。不同阶段蛾类群落相似性水平均很低,其中以7月上旬与7月中旬相似性水平最高,为0.526 3;相异性以6月中旬与7月上旬最高,为0.888 9。     

药用植物提取物对草莓灰霉病菌抑菌活性研究

用丙酮为溶剂提取7种药用植物材料粉末,得到提取物母液。采用生长速率法和叶片离体接菌法测试提取物对草莓灰霉病菌的室内抑菌作用。在供试的7种植物材料中,五味子对菌丝生长的抑制率最高,达到95.65%,其次为薏苡,抑菌率为91.30%,决明、酸浆的抑菌率均达到了85%以上。结合叶片离体接菌法的试验结果,认为五味子和酸浆可以作为重点进行深入研究。     

基于CRITIC-GR-TOPSIS法的烟台市水资源承载力综合评价

[目的]对山东省烟台市水资源承载具体状况进行定量与定性分析,提出相应提高水资源承载力的对策和建议,为实现烟台市水资源可持续发展提供科学参考.[方法]建立涵盖水资源、社会、经济和水环境4个准则层的评价指标体系,运用CRITIC-GR-TOPSIS法,对2003-2018年烟台市水资源承载力进行综合评价,以相对贴近度Cj作...     

自然感染日本血吸虫病耕牛血清循环抗原消长规律的研究

为了观察疫区自然感染日本血吸虫病耕牛血清循环抗原消长规律,本试验将血吸虫病非疫区的水、黄牛各１０头,转运至安徽省血吸虫病疫区,接受为期８周的自然感染。用斑点酶联免疫吸附试验测定牛血清循环抗原。结果,水、黄牛血清循环抗原滴度均于自然感染第４周后明显上升,水、黄牛自然感染第８周的血清循环抗原最高滴度分为１∶１０２４０和１∶５１２０,最低滴度则分别为１∶１２８０和１∶６４０,水牛循环抗原滴度高于黄牛。虫荷数与血清循环抗原滴度未见有相关性。     

河北进境种用动物衣原体血清学检测

衣原体病是一种重要的人畜共患病,给养殖业带来巨大的经济损失,同时严重威胁从业人员的身体健康。本研究对河北辖区引进的2批种鸡、2批种鸭及2批种猪进行抽样,使用间接血凝试验（IHA）检测引进种用动物的衣原体抗体。结果表明：衣原体IHA抗体阳性率为15.7%。在种鸡、种鸭和种猪中均检测到衣原体IHA抗体,阳性率分别为18.1%、4.2%和20%。这说明在引进种用动物中存在着较高的衣原体抗体阳性率,需要加强对该病的检测。     

The 16MΔvjbR as an ideal live attenuated vaccine candidate for differentiation between Brucella vaccination and infection

Brucellosis brings great economic burdens for developing countries. Live attenuated vaccines are the most efficient means for prevention and control of animal Brucellosis. However, the difficulties of differentiating of infection from vaccine immunization, which is essential for eradication programs, limit their applications. Therefore, the development of a vaccine that could differentiate infection from immunization will overcome the limitations and get extensive application. VjbR is a quorum sensing regulator involving in Brucella's intracellular survival. The vjbR∷Tn5 mutants have been proven effective against wild type strain challenge, implying its possibility of use in vaccine candidate development. To further evaluate this candidate gene, in the present study, the antigenicity of purified recombinant VjbR protein was analyzed. Antibodies to Brucella melitensis VjbR could be detected in sera from patients and animals with brucellosis but not in control ones, implying the potential use of this protein as a diagnostic antigen. Then a vjbR mutant of B. melitensis 16M was constructed by replacing the vjbR with kanamycin gene. The mutant showed reduced survival in macrophage and mice. Vaccination of BALB/c mice with 16MΔvjbR conferred significant protective immunity against B. melitensis strain 16M challenges, being equivalent to which induced by the license vaccine Rev.1. The vjbR deletion mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon and interleukin-10. The most importance is that, the use of vjbR mutants as vaccines in association with diagnostic tests based on the VjbR antigen would allow the serological differentiation between infected and vaccinated animals. These results suggest that 16MΔvjbR is an ideal live attenuated vaccine candidate against B. melitensis and deserves further evaluation for vaccine development.     

哺乳与保育仔猪腹泻的综合防治

<正>我国仔猪腹泻现象十分普遍,导致饲料报酬较低、成活率下降、生长发育停滞。引起腹泻发生的病因往往是多因素相互作用,呈多重感染或交叉混合感染,临床诊断防治困难,严重威胁着养猪业的健康发展。