菜蚜对白菜孤丁病传毒效能差异的研究

白菜孤丁(芜菁花叶)是京、津秋菜上的重要病毒病害,以蚜虫为主要传毒介体。以白菜为寄主的桃蚜(Myzus persicae(Sulz))和菜缢管蚜(Hyadaphis erysimi pseudobrassicae(Davi))(=Rhopalosiphum pseudobrassicae Davis)都能传毒(裘维蕃1957,Kennedy 1962)。由于芜菁花叶病毒是口针系病毒(即“非持久性”病毒)(Kennedy 1962),蚜虫的得毒与传     

不同CO_2浓度条件下灰飞虱体内RSV的定量检测

灰飞虱的群体带毒率及体内条纹病毒(rice stripe virus,RSV)的准确检测是预测水稻条纹叶枯病在CO2浓度升高背景下能否大发生的重要参考依据之一。本研究应用quali-fiedRT-PCR(qRT-PCR)测定不同CO2浓度条件下灰飞虱体内的RSV含量。结果表明:在试验的3个CO2浓度梯度(370、470和570μl.L-1)下,470μl.L-1的CO2浓度最适合RSV在灰飞虱体内的增殖,此方法与现已普遍应用的酶联免疫检测法(enzyme-linkedi mmu-nosorbnent assay,ELISA)和斑点免疫结合检测法(dotimmunobinding assay,DIBA)相比,具有快速、灵敏和特异性强的优点,且不需制备抗血清,适于普及应用。     

点免疫结合测定法检测谷氨酸产生菌噬菌体污染

点免疫结合测定法(简称DIBA法)是近几年建立的检测抗原抗体的新方法。关于用该法对照常规双扩法、对流免疫电泳法检测某些动、植物病毒从而表现出很高的灵敏度方面已有一些报道,但尚未见到有关用DIBA法检测噬菌体方面的有关材料。本文仅以谷氨酸产生菌T_(613)噬菌体为抗原,制备特异抗血清;并用DIBA法对照SPA法检测T_(613)菌噬菌体,发现在抗原抗体反应中DIBA法比SPA法具很高的灵敏度。现将结果报道如下。材料与方法一、材料 1、T_(613)菌噬菌体裂解液。 2、T_(613)菌噬菌体抗血清。 3、冻干酶联葡萄球菌A蛋白(HRP     

禾谷缢管蚜在三个小麦品种上取食行为的EPG比较

应用刺探电位图谱（EPG）技术对禾谷缢管蚜Rhopalosiphum padi在不同小麦品种(Ww2730、小偃22和Batis)苗期的取食行为进行了比较研究。结果表明：在小偃22上蚜虫开始取食的第1次刺探时间最晚,且持续时间最短;在Ww2730上取食受到机械阻力的个体最多,且出现F波的几率和持续时间最长;两品种上蚜虫在木质部主动摄取汁液（G波）花费的时间最长。 在Batis上,蚜虫口针第1次到达韧皮部时需要分泌较多水溶性唾液(E1波),但随后只需分泌较少的水溶性唾液就可以成功取食,而且被动吸食韧皮部汁液的时间（E2波）最长。蚜虫口针在到达小偃22韧皮部取食之前,出现多次的口针试探、回撤,并且多次、多量分泌水溶性唾液（E1波）;虽然蚜虫在小偃22上口针最先到达韧皮部,但被动吸食韧皮部汁液的时间（E2波）最短。由此得出结论：小偃22表皮部、韧皮部存在阻碍禾谷缢管蚜取食的物理和生化因素; 禾谷缢管蚜在Ww2730取食遇到更多的是细胞间机械阻力; Batis是较感蚜的品种。     

桃蚜、萝卜蚜的种内密度和种间竞争效应

在温室内不同密度条件下,研究了桃蚜和萝卜蚜在甘蓝上的种内密度效应和种间竞争作用。结果表明：单独饲养时,在5头／株和10头／株密度下,两种蚜虫种内密度效应均较弱;而在15头／株时,桃蚜和萝卜蚜的寿命和产蚜量都随之显降低,说明当两种蚜虫达到一定的拥挤程度时,种内密度对种群均产生一定的负效应。两种蚜虫共存时,单头产蚜量均比单独饲养时显下降,种问竞争作用明显。在10、15头／株密度下,桃蚜的竞争作用大于萝卜蚜,萝卜蚜的寿命和单头产蚜量都极显低于桃蚜。     

麦长管蚜对E-β-法尼烯的嗅觉行为反应

【目的】测定麦长管蚜Sitobion avenae Fabricius对E-β-法尼烯(E-β-farnesene,EβF)矿物油溶液反应的最低阈值浓度,为EβF的田间应用提供依据。【方法】观察麦长管蚜3龄若蚜对不同浓度EβF的逃逸行为和"Y"型管嗅觉行为反应。每天定时分5次(9:00,11:30,14:00,16:30和19:00)滴加10μL EβF于滤纸上,滤纸用牙签固定于麦苗盆中心,持续处理5 d。每盆麦苗处理前接1龄若蚜15头。记录成蚜翅型及2周后蚜虫总数量。【结果】随着EβF浓度升高,麦长管蚜3龄若蚜3 min内逃离数显著增加,有翅蚜比例显著增加,种群个体数量显著下降,驱避效果明显增强。EβF浓度为200 ng/μL和≥600 ng/μL使蚜虫逃离数显著增加(P0.05)。"Y"型管选择行为测试结果表明,EβF≥600 ng/μL对3龄若蚜具有极显著的驱避作用(P0.01)。与对照相比,EβF≥600 ng/μL处理极显著提高了有翅蚜比例(P0.01);EβF≥400 ng/μL极显著抑制蚜虫种群个体数量增长(P0.01),但与600 ng/μL处理差异不显著。【结论】600 ng/μL EβF矿物油溶液为麦长管蚜驱避剂的最低阈值浓度。     

石蒜凝集素基因转化切花菊及抗蚜性鉴定

以切花菊'神马'叶片为外植体,采用根癌农杆菌介导法将长筒石蒜凝集素基因LLA导入菊花.结果表明,'神马'叶片对潮霉素(Hyg)十分敏感,叶盘再生筛选以8～10 mg·L~(-1)为宜,生根筛选以18 mg·L~(-1)为宜;羧苄青霉素抑菌浓度早期以500 mg·L~(-1)为宜,后期以250～300 mg·L~(-1)为宜.Hyg抗性再生植株经PCR、RT-PCR检测初步证实外源基因已转入7个转化株系的植物基因组DNA中并发生转录.转基因植株幼苗人工接种蚜虫实验表明,不同转化株系的抗蚜性差异较大,蚜口密度抑制率为12.2%～76.8%不等,平均蚜口密度抑制率为41.8%.     

高粱抗蚜研究进展

高粱(Sorghum bicolour)是世界上最重要的粮食、饲料、酿造和能源作物之一, 也是C₄植物研究的模式植物。蚜虫是农业生产上的重要害虫, 几乎危害所有的栽培作物。危害高粱的蚜虫主要包括高粱蚜(Melanaphis sacchari)、麦二叉蚜(Schizaphis graminum)和玉米蚜(Rhopalosiphum maidis)。高粱的抗蚜资源尚不丰富且缺乏深入系统的研究。目前研究较多的是麦二叉蚜的抗性遗传方面, 已定位20个抗性QTLs, 单一QTL对抗性差异贡献率最高可达80.3%, 对高粱蚜和玉米蚜的研究尚需进一步加强。高粱的理化特性与其抗蚜性能相关, 故可与育种实践相结合。高粱和蚜虫(Acyrthosiphon pisum)的全基因组测序工作已经完成, 这将有助于蚜虫-植物间的相互作用关系及植物对蚜虫的抗性机制研究。目前已克隆到2个抗蚜基因, 且多个抗蚜基因(位点)已被定位在染色体上。该文重点综述了上述研究成果并对高粱抗蚜的研究前景进行了展望。     

矿物油处理对马铃薯长管蚜定向和取食行为的影响（英文）

大田和实验室研究均表明矿物油的施用可有效降低蚜虫对非持久性病毒的传播。我们分别于矿物油喷施马铃薯植株24 h和7 d后,调查其对马铃薯长管蚜Macrosiphum euphorbiae行为的影响;采用暗室生测法调查了蚜虫对处理的植物挥发性化合物的反应;采用刺探电位技术（EPG）评价了矿物油处理对蚜虫取食行为的影响。结果表明：矿物油处理导致植物对寄主的引诱作用失效,这种效果至少持续24 h。矿物油处理马铃薯植株24 h和7 d后,蚜虫对处理植株的取食行为发生改变。开始记录至第1次刺探所需时间降低,但只在处理7 d后显著降低,提示矿物油处理有助于蚜虫口针的穿刺。然而,流涎阶段以及韧皮部汁液吸食阶段（摄食阶段）显著缩短。本研究中观察到的蚜虫行为的改变不能充分解释施用矿物油的大田中为什么出现7 d 的保护作用,因此可能还存在其他的机制。     

高梁抗蚜研究进展

高粱(Sorghum bicolour)是世界上最重要的粮食、饲料、酿造和能源作物之一,也是C4植物研究的模式植物.蚜虫是农业生产上的重要害虫,几乎危害所有的栽培作物.危害高粱的蚜虫主要包括高粱蚜(Melanaphis sacchan)、麦二叉蚜(Schizaphis graminum)和玉米蚜(Rhopalosiphum maidis).高粱的抗蚜资源尚不丰富且缺乏深入系统的研究.目前研究较多的是麦二叉蚜的抗性遗传方面,已定位20个抗性QTLs,单一QTL对抗性差异贡献率最高可达80.3％,对高粱蚜和玉米蚜的研究尚需进一步加强.高粱的理化特性与其抗蚜性能相关,故可与育种实践相结合.高粱和蚜虫(Acyrthosiphon pisum)的全基因组测序工作已经完成,这将有助于蚜虫-植物间的相互作用关系及植物对蚜虫的抗性机制研究.目前已克隆到2个抗蚜基因,且多个抗蚜基因(位点)已被定位在染色体上.该文重点综述了上述研究成果并对高粱抗蚜的研究前景进行了展望.     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.