感染番茄斑萎病毒和番茄环纹斑点病毒的植物叶片细胞病理变化观察

应用透射电子显微镜观察比较了番茄斑萎病毒（ TSWV）和番茄环纹斑点病毒（ TZSV）感病植物叶片的细胞超微结构,发现两种病毒在病变细胞内的形态及细胞病理变化特征相似,但病毒含量及细胞受损程度存在明显差异。与TSWV相比,TZSV侵染细胞的病变程度更为严重,叶绿体产生大的囊泡,片层结构被破坏,线粒体也发生囊泡化,而TSWV侵染的细胞内线粒体保存相对完好。高压冷冻－冷冻置换制备的样品细胞病理结构与常规化学固定的相似,但对膜结构的保存更加良好。该结果从细胞病理学上证明了TZSV在田间对农作物造成的危害更加严重。     

植物病毒感染寄主叶绿体的形态结构变化

植物病毒侵染系统寄主后产生显著的花叶症状 ,细胞内叶绿体结构和功能遭到破坏。在褪绿部位叶绿体发育不良 ,基粒类囊体垛叠差 ,体积变小、数量减少 ,有的发生团聚或接合 ,成熟叶绿体往往肿胀、片层松散 ,甚至整体瓦解。现已了解烟草花叶病毒 TMV、黄瓜花叶病毒 CMV、马铃薯 Y病毒 PVY的外壳蛋白 CP存在于被侵染的寄主细胞叶绿体中 ,特异性结合在类囊体膜的光系统 上 ,阻止了电子在传递链中的传递 ,推测电子传递链中断导致氧原子积累 ,降解叶绿体 ,是导致花叶症状的决定性因素。我们在植物病毒的细胞病理学研究中 ,对芜菁花叶病毒 Tu…     

应用高压冷冻-冷冻置换技术研究受Potyvirus侵染的寄主细胞超微结构

应用高压冷冻-冷冻置换技术（HPF-FS）制备了马铃薯Y病毒属的小西葫芦黄花叶病毒（ZYMV）和大豆花叶病毒（SMV）侵染寄主植物叶细胞的超薄切片样品,并与传统化学固定方法进行比较。透射电镜观察结果显示：病毒粒子和内含体的形态分布在两种方法处理的样品中无明显差异,但高压冷冻样品的细胞超微结构精细,细胞壁与细胞质之间边界清晰,质膜平滑而完整,细胞基质丰富;细胞核和叶绿体、线粒体等形态饱满,高尔基体潴泡结构及分泌小泡清晰,在ZYMV感染细胞的叶绿体中观察到囊泡结构。而化学处理的样品普遍存在细胞结构的收缩和变形,特别是质膜褶皱,与细胞壁分离,叶绿体呈梭形,片层结构发生改变,高尔基体潴泡结构及分泌小泡相当少见。实验结果有利于正确区别病毒所引起的细胞病理变化和化学处理而产生的人工假象。     

大蒜病毒原与其寄主细胞病理变化的电镜研究

电镜检查发现田间4个品种栽培大蒜各部位组织都含大量线形病毒粒子,长度为300nm～2200nm,但较多的集中在750nm和600nm两个范围内。感病大蒜叶组织细胞质大量存在着圆柱状内含体,内含体显然与内质网、质膜和胞间连丝有关。病毒粒子散布在细胞质中,有些附着在内含体上,未见病毒聚集体。病变细胞严重空泡化,有些细胞质中出现大量含纤维状物的小囊泡和类似内质网膨大的结构,同时伴随着大量病毒粒子。叶绿体和根细胞中的前质体产生特殊泡状腔结构,细胞核中未见内含体和病毒粒子。     

病毒感染电镜诊断和病毒分类命名的新进展

病毒感染电镜诊断和病毒分类命名的新进展陈德蕙张贺秋王国华（军事医学科学院基础医学研究所，北京１００８５０）电镜是检出病毒感染和对病毒进行分类、鉴定的有力工具。从理论上讲，电镜可以检出任何在体外或体内组织细胞内复制、增殖的病毒及其所产生的细胞病变，并提...     

莴笋感染番茄斑萎病毒(TSWV)——病毒粒子分布与亚细胞病变特征

莴笋是西藏昌都市露地栽培的主要蔬菜种类之一,近年来斑萎病发生普遍,发病率达到了80%以上,引起严重的经济损失,前期研究表明发病植株受到番茄斑萎病毒(TSWV)侵染。为明确该区域莴笋感染TSWV不同时期病毒粒体分布与亚细胞病变的特征,为病毒病的精准诊断与绿色防控提供依据,本研究采集了西藏昌都市卡若区莴笋不同发病时期的样品,应用TSWV-N基因序列设计引物,通过RT-PCR扩增克隆与测序分析,根据N基因序列推导N蛋白氨基酸序列比对,明确采集样品受到TSWV侵染。采集不同发病时期的样品进行负染色和超薄切片制样透射电子显微镜观察,发现早期感病叶片(症状为轻微褪绿)中病毒粒体相对含量较少,TSWV粒体分布于细胞质中,叶绿体噬锇颗粒明显增加,线粒体嵴膜部分降解,少部分细胞的液泡内有较多TSWV粒体聚集于细胞质内的囊泡中;中期感病叶片(褪绿或黄化斑)中,病毒粒体相对含量较高,较多TSWV粒体聚集于细胞质内质网池中,叶绿体膜系统降解,噬锇颗粒增加,线粒体增多;后期感病叶片(坏死斑)中,病毒粒体相对含量高,叶绿体、线粒体等细胞器降解,有大量TSWV病毒粒体聚集于残存的细胞质内囊泡中。TSWV粒体相对含量...     

植物光诱导延迟发光介导的酸性环境污染监测

酸雨和大气污染会对植物叶片内叶绿体的结构和功能产生影响，而植物光诱导延迟发光（DLE）被认为主要产生于叶绿体的PSⅡ中。利用自制的弱光探测系统，以生长周期长、叶片面积大的紫荆花叶片作为实验材料，研究了模拟酸雨和SO2对其DLE特性的影响。结果发现，绿色植物叶片光诱导DLE强度的变化能很好地反映植物叶片中叶绿体完整性以及叶绿体功能的变化。凶此，可以用DLE强度的变化来表征环境对植物的胁迫程度，有望为环境污染监测及生物学评价提供新的手段。     

两种球状病毒感染寄主植物的超微结构研究

电子显微镜观察受蚕豆萎蔫病毒(Broad bean wilt virus简称BBWV)感染的昆诺阿藜呈现系统花叶的褪绿斑区域,发现BBWV粒子集中在细胞的叶绿体中,有的叶绿体较小,片层发育不良,有的结构肿胀,叶绿体空泡化。BBWV使筛管细胞的细胞壁增生,筛板两侧有旁泡体出现,还使薄壁细胞的细胞壁呈瘠状衍生,细胞质有空泡出现。     

水稻矮缩病毒云南、浙江分离株侵染水稻植株的细胞病理比较研究

为探讨水稻矮缩病毒（RDV）不同分离株侵染寄主植物的细胞病理学变化,验证RDV部分基因差异是否引起致病性差异,本文应用超薄切片电镜技术比较观察RDV云南分离株和浙江分离株侵染水稻的细胞病理.结果显示,RDV云南分离株侵染的水稻叶片中充满病毒粒体的细胞呈条带状分布,呈现出明显的侵染中心.在充满病毒粒体的细胞周围,相邻细胞不同程度地病变,叶绿体膜系统消失,部分叶绿体中含有病毒颗粒,线粒体残体及细胞质中有分散或聚集的病毒粒体,细胞核中未见病毒粒体;离侵染中心较远的细胞中亚细胞结构较完整.RDV浙江分离株侵染的水稻叶片中部分细胞充满病毒粒体,无明显的条带状分布,其他细胞病理特征与RDV云南分离株侵染的水稻叶片相似.这些结果表明,RDV不同分离株侵染寄主植株的细胞病理特征无显著差异,对其致病性的差异需进一步研究.     

发育期黄肉桃色素、质体细胞学和叶绿素荧光的变化

为探究发育期黄果肉桃果实质体发育情况，以黄肉桃‘23－40’为研究对象，对发育期桃果实，分别采用分光光度法测定色素变化，冷冻切片法观察质体的形态，Mini?Imaging?PAM叶绿素荧光成像仪测定不同区域叶绿素荧光。结果表明：（1）随着果实发育，光合色素组分处于动态变化之中，叶绿素a（ Chl． a）、叶绿素b（ Chl． b）含量、Chl． a／b和Chl．（a＋b）／Car．（类胡萝卜素）均下降，而类胡萝卜素（Car．）和花青素（Ant．）含量上升。（2）盛花后65天，桃果实表皮下第4～12层果肉细胞分布大量叶绿体，且叶绿体数量由外向内逐渐减少；随着发育，叶绿体体积缩小，数量下降，类胡萝卜素的积累使质体由绿色向黄色转变，果实成熟后，质体类囊体解体，叶绿体转化为有色体。（3）随着果实发育，桃中果皮捕光能力和光合潜力逐渐减弱，叶绿体的光能利用效率先上升后下降；且果实中果皮外侧的荧光活性比内侧强，成熟桃果实中果皮基本不具备光合能力。这些结果暗示黄肉桃发育过程中色素成分含量、质体形态分布和光合能力具有时空差异。     

百合病毒病原的检测诊断

应用电镜和ELISA检测查明浙江丽水和杭州栽培的百合受到黄瓜花叶病毒(CMV)及多种线状病毒侵染。寄主反应测定显示侵染百合的植物病毒寄主范围都很窄,不能通过汁液摩擦接种侵染昆诺藜、苋色藜、普通烟、心叶烟等6科12种指示植物。在64个ELISA检测样品中有26个受到CMV侵染,侵染率达40．6％;在75个负染色检测样品中有58个观察到线状病毒,侵染率达77．3％;在40个被线状病毒侵染的样品中有27个观察到细胞质风轮状内舍体,表明受到马铃薯Y病毒属成员的侵染,侵染率达67．5％。从不同线状病毒粒子形态及所引起的细胞病理变化来看,可能分属于马铃薯Y病毒属、麝香石竹潜隐病毒属和马铃薯X病毒属。     

基于主成分分析和人工神经网络的五味子质量鉴定方法研究

提出了一种采用近红外光谱技术结合人工神经网络对中药五味子质量进行鉴别的新方法.利用近红外光谱仪获得了3种不同来源地五味子合计90个样本的光谱曲线,采用主成分分析法对光谱数据进行了聚类分析,并结合人工神经网络技术建立了五味子甲素、五味子乙素和五味子醇甲三种木脂素类化合物的分析模型.主成分分析表明,前5个主成分的累积贡献率为98.75%,具有很好的聚类作用.在主成分分析的基础上,取前5个主成分的18个吸收峰作为网络的输入节点,取3项指标作为输出节点,建立了一个18(输入节点)-10(隐含层节点)-3(输出节点)的三层人工神经网络模型.五味子甲素、五味子乙素和五味子醇甲三项指标的人工神经网络模型预测值的平均相对误差分别为4.07%、2.65%和6.15%,与高效液相色谱法测定值的符合程度很高.该模型具有很好的预测能力,可用于大批量五味子的质量检测和五味子生产加工过程中的质量控制.     

Identifying Discriminative Amino Acids Within the Hemagglutinin of Human Influenza A H5N1 Virus Using a Decision Tree

Recently, the H5N1 virus has had an increasingly important impact on human life. This is because more and more people are becoming infected with this virus, and the possibility of a serious pandemic with human to human transmission is looming. This might occur if the genome of this influenza virus mutates either by antigenic drift or by antigenic shift, especially if there is a mutation of the hemagglutinin (HA) glycoprotein. The HA is the surface glycoprotein, and it binds to sialic acid of the host cell surface receptor. Thus, the combination of HA and sialic acid are central to whether influenza virus infects humans. In this study, we selected 497 HA protein sequences from the National Center for Biotechnology Information (NCBI) Influenza Resource database, and used a decision tree method to identify discriminative amino acids in the HA protein sequences that may possibly influence the binding of HA to sialic acid. Four such amino acid positions at 54, 55, 241, and 281 were identified and these may play an important role in infection by H5N1 influenza virus.      

侵染西瓜的黄瓜绿斑驳花叶病毒快速检测

黄瓜绿斑驳花叶病毒（ CGMMV）是危害西瓜生产的重要病害,造成西瓜果实腐烂,失去商业价值。应用透射电子显微镜和单抗dot?ELISA技术对采自浙江温岭的西瓜病叶进行快速病原检测,电镜负染色观察到病株汁液中存在大量刚直杆状的病毒粒子,超薄切片观察到细胞质内存在整齐排列的杆状病毒聚集体,与烟草花叶病毒属（ Tobamovirus）的形态特征相符;进一步采用dot?ELISA技术进行血清学检测,显示西瓜病叶与CGMMV特异性抗体呈阳性反应,检测结果表明感染西瓜的杆状病毒为CGMMV。从而为侵染西瓜的CGMMV提供快速检测途径。     

Budding of fowlpox and pigeonpox viruses at the surface of infected cells

Chick embryo fibroblasts and chorioallantoic membranes infected with fowlpox virus (FWPV) or pigeonpox virus (PPV) were examined by transmission and scanning electron microscopy. Immature virus particles were observed in finely granular areas, i.e. virus factories, of the cytoplasm. These particles had various forms depending on their stages of development. Many tubular structures were also seen in these regions. Mature virus particles with ellipsoidal or brick-shaped forms enclosing electron-dense cores were detected throughout the cytoplasm. Notably, there was a high frequency of virus budding at the cell surface, but only occasional virus wrapping in the cytoplasm. Another remarkable feature of the infected cells was accumulation of many virions just beneath the plasma membrane, indicating that this phenomenon is closely related to virus budding. Based on the observed frequency of budding, this mechanism seems to be the predominant way for FWPV and PPV to exit the cell.     

Poxvirus virions: their surface ultrastructure and interaction with the surface membrane of host cells

Virions of vaccinia and orf viruses were examined by ultrahigh-resolution scanning electron microscopy using a non-coating method. Intracellular mature particles of vaccinia virus appeared to be covered with a net and ultrastructurally their surface consists of many fine ridges and globules, while the surfaces of orf virus mature particles recovered from infected cells consist of spirally running protrusions. The ridge-like structures of vaccinia virus were presumed to correspond to surface tubules shown by negative staining of this virus, while the spiral protrusions of orf virus were presumed to correspond to spiral threads having a criss-cross appearance by the same staining. Using scanning electron microscopy in which the samples were prepared by the conventional method, we observed: (i) many virions, i.e. one or two hundreds, or occasionally more reaching about one thousand particles, of the IHD strain of vaccinia virus, (ii) many or a moderate number of virions, i.e. about one hundred or fewer particles, of the 58 strain of cowpox virus and (iii) rather few virions, i.e. several tens or fewer particles, of the Iwate strain of orf virus on the free surface of each cell infected with these viruses. It must be noted that the number of virions detected considerably differed in respective cells examined. Virus budding was frequently observed at the cell surface of monolayer cells infected with vaccinia virus but it was never detected with cowpox or orf virus, indicating a difference in the mechanism of virus release between vaccinia and the other two viruses. When whole cells infected with vaccinia virus were examined by a combination of high-voltage and scanning electron microscopies, virions on the cell surface and those inside the cells were clearly differentiated. All virions on the cell surface had an envelope, and some of the envelopes had a slack and/or one or more bulges.     

Ultra-high-resolution scanning electron microscopy of vaccinia virus and its recombinant carrying the gag gene of human immunodeficiency virus type 1.

FL cells infected with vaccinia virus or its recombinant carrying the gag gene of human immunodeficiency virus type 1 (HIV-1) were examined by ultra-high-resolution scanning electron microscopy. Virions, whether located extracellularly or intracellularly, had a brick-shaped or watermelon appearance as a whole. Extracellular virions observed on the surface of infected cells had variable surface ultrastructures depending on the manner in which particular virions were wrapped in cell membranes. Most of the intracellular naked virions adherent to the inner face of cell surface membranes clearly exhibited ridgy, rod-shaped or globular surface structures on their surface. HIV-like particles with a diameter of about 100 nm and virions of vaccinia virus were both observed distinctly on the surface of FL cells infected with the recombinant virus.     

The level of antibodies to Epstein-Barr virus antigens in the blood serum of the inhabitants of southern Siberia and the Far East

Antibodies to Epstein-Barr virus have been detected in sera from 1538 healthy adult persons living in the south of Siberia and Far East. It has been shown that the virus infectivity varied from 77% in Russians of the Yakutsk ASSR to 100% in Orochi and Russians residing in the territory of the Gorno-Altai Autonomous Province. Antibody levels to the Epstein-Barr virus for inhabitants of the south regions were higher than those for inhabitants of the north regions.