超强毒RB1B株马立克氏病UL49基因的克隆和序列分析

鸡马立克氏病病毒UL49基因编码的被膜蛋白VP22在病毒的复制和传播过程中具有非常重要的作用。根据已发表的MDV-1 Md5株的序列,从马立克氏病超强毒RB1B株感染的鸡胚成纤维细胞中提取病毒基因组DNA,经PCR扩增UL49基因并克隆入pMD18-T Simple载体。RB1B株UL49基因经核酸序列测定分析,全长为750碱基。将RB1B株与Md5株和GA株的UL49进行比较,发现马立克氏病病毒强毒株间的UL49基因高度同源,为利用RB1B的UL49基因作为基因治疗的靶序列奠定了理论基础。     

无致病性马立克氏病病毒和致弱马立克氏病病毒疫苗的传染性和免疫性

用MDV-19疫苗(无致病性马立克病病毒)、AM-1(致弱马立克氏病病毒)疫苗和NSW1/70(火鸡疱疹病毒)疫苗接种免疫具有不同免疫史的亲代的雏鸡,然后以马立克氏病强毒攻击,比较其反应和保护力。MDV—19疫苗免疫的有母源抗体     

蛋鸡马立克氏病的诊断与防治

鸡马立克氏病是由B型疱疹病毒引起的以淋巴样胞增生为特征的肿瘤性传染病.该病引起瘫痪、多发性神经炎、神经淋巴瘤病、灰眼、虹膜炎、眼色素层炎、内脏淋巴瘤病和皮肤型白血病等.鸡马立克氏病引起鸡群免疫抑制和高死亡率,给养鸡户带来巨大损失,马立克氏病一年四季均可发病,是严重危害养鸡生产的传染病之一.     

应用羽囊琼脂扩散法检查鸡马立克氏病的试验报告

一、经大体剖检和组织学检查确诊为马立克氏病的病鸡,采其羽囊与确诊为马立克氏病病鸡的血清作琼脂扩散试验,筛选出阳性反应显著的血清,作为鸡马立克氏病阳性血清。用此种阳性血清与其他受检鸡的羽囊作琼脂扩散试验,以检查鸡的马立克氏病。在三批试验中,第一批由马立克氏病鸡群中剔出的病鸡,检出的阳性率为60％(61/102个);第二批四群发生马立克氏病的鸡群共检查284个,阳性率由10％(5/151个)至58％(26/54个);三群无马立克氏病病史的鸡群,共抽查80个,阳性率由0％(0/20个)至6.3％(2/30个)。试验结果表明,应用此法大部分马立克氏病鸡可被检出。二、阳性反应鸡可确诊为马立克氏病。但由于有少数马立克氏病的病鸡应用此法检查并不出现反应,所以呈现阴性反应的鸡则不能完全排除无马立克氏病的感染。本法除可检出有症状的病鸡外,不少无症状的感染鸡,亦可被检出。三、在发病的鸡群中,用此法检查以剔除阳性鸡,初步表明可以减少本病传染的机会,起到缩小或阻止疫情发展的作用。于对防制本病起到显著作用。四、用羽囊浸液或直接用羽囊作琼脂扩散试验检查马立克氏病,敏感度高,方法简单易行,且毋须特殊设备,在基层兽医单位和鸡场内均可进行。因此,是一种较为理想的检查鸡马立克氏病的血清学方法。     

马立克氏病鸡MDV血清基因的克隆与鉴定

[目的]克隆马立克氏病鸡MDV血清基因,并对其进行鉴定。[方法]从潜伏期感染马立克氏病鸡淋巴组织中提取基因组DNA,采用梯度PCR扩增马立克氏病毒的L-meq基因。将其插入pMD18-T克隆载体并进行测序,并用DNAman软件进行序列分析。[结果]获得的DNA片段的序列与已发表的L-meq基因序列相一致,表明该试验成功获得了目的基因。[结论]该研究可为鸡马立克氏病的预防与治疗提供新思路和新方法。     

探析鸡马立克氏病防制方法

鸡马立克氏病存在于世界所有养禽国家和地区,其危害随着养鸡业的集约化而增大。鸡群中一旦发生该病,即可引起大批死亡,甚至全群覆没,是中国三大重点控制的疫病之一。鸡马立克氏病防制一直是理论和实践研究的热点。笔者分析了鸡马立克氏病防制现状,基于理论和生产实践,提出了鸡马立克氏病防制方法的改进与建议。     

鸡马立克氏病毒Ⅰ型毒株的分离和鉴定

从鸡马立克氏病（ＭＤ）疫苗免疫的发病鸡群中采集肝、脾、血液等病料，经鸭胚成纤维细胞（ＤＥＦ）培养盲传数代，分离到１株（ＭＤＶ）暂定名为沪Ｘ株。该病毒在ＤＥＦ培养上出现典型的ＭＤＶ细胞病变。电镜下病毒大小为１００ｎｍ左右，呈椭圆半开圆形，位于细胞核内。细胞培养物经饱和硫酸铵浓缩后，与标准的马立克氏阳性血清出现琼扩沉淀线。病毒按种ＳＰＦ鸡后，鸡群主要表现内脏肿瘤，并回收到ＭＤＶ，表明分离的沪Ｘ株具有致病性，属于马立克氏疱疹病毒Ⅰ型     

蛋鸡群发生马立克氏病继发H9亚型禽流感的诊治

马立克氏病是一种重要的免疫抑制病,严重影响养鸡业的健康发展。通过对一例发生马立克氏病继发H9亚型禽流感的蛋鸡群的症状进行分析、剖检变化及实验室诊断,提出了治疗和预防措施,为马立克氏病和H9亚型禽流感的防治提供参考。     

一起鸡马立克氏病诊断与防治

鸡马立克氏病是一种常出现在鸡群中的淋巴组织增生性疾病,主要是由于马立克氏病病毒诱发,病鸡主要特征是淋巴肿瘤出现在病鸡皮肤、肌肉、性腺、外周神经等部位。虽然畜禽养殖目前有多种疫苗可用于预防鸡马立克氏病,但现实中由于多种因素的制约,常导致鸡马立克氏病免疫失败。本文就一起鸡马立克氏病的诊断与防治进行探讨。     

鸡马立克氏病的治疗

鸡马立克氏病(MD)是鸡常见的一种淋巴组织增生性疾病,是由马立克氏疱疹病毒引起的具有高度传染性的肿瘤疾病,主要危害3-5月龄的鸡,死亡率可高达80%,尤其是未经马立克氏病疫苗免疫的鸡群更易爆此本病。     

Seed Health Status of Sweet Corn (Zea mays L. saccharata Sturt) from Five Areas in China and Effect on Field Seedling Emergence

The health status of 18 sweet corn (Zea mays L. saccharata Sturt) hybrids classified to two types, collected from five areas in China, was examined by PDA method, and factors influencing seed health and relationships between seed health and field seedling emergence were studied. Seventeen fungal genera were isolated and Fusarium was the most frequently isolated. There were significant differences both in incidence of Fusarium and in percentage of infected seeds among 18hybrids. Research also showed that significant and consistent differences both in seed-borne fungal taxa and in percentage of infected seeds existed between two types of sweet corn. Sugar enhanced corn is more slightly infected than super sweet corn both in fungal taxa (13 and 16, respectively) and in percentage of infected seeds (62.0 and 79.2%, respectively).There were also significant differences both in seed-borne fungal taxa and in percentage of infected seeds among five areas. Seeds from South China were most severely infected, for there were 14 fungal genera detected and the percentage of infected seeds was highly 99.1% while those from Northwest China were slightly infected, for there were 10 fungal genera detected and the percentage of infected seeds was only 14.3%. Further research showed that there were significant negative correlations both between incidence of Fusarium and percentage of field seedling emergence and between percentage of infected seeds and percentage of field seedling emergence. Percentage of field seedling emergence could be estimated by regression equations built by regression analysis.     

青枯雷尔氏菌在芝麻植株内的分布及消长动态

芝麻青枯病是我国南方芝麻生产上的重要土传病害。通过测定健康植株、不同发病时期的自然病株及人工接种病株内不同部位青枯雷尔氏菌数量,旨在明确病菌在芝麻植株内的分布及消长动态。结果表明:发病初期,病株内青枯雷尔氏菌总数量随着病情的发展而增加,之后随着病情严重度的加重而下降。病菌的致病力则随着病情发展呈现持续上升的趋势。检测的所有芝麻健株各部位均无青枯雷尔氏菌分布,说明芝麻植株不存在无症状侵染现象。青枯雷尔氏菌在芝麻病株内的分布呈现丰富的多态性,自然病圃和灌根接种的Ⅱ类、Ⅲ类病株各部位菌量分布随着植株高度的升高而递减,但其Ⅰ类病株中下部菌量却高于基部。针刺接种的Ⅰ类、Ⅱ类和Ⅲ类病株,接种点以下的根部和基部均有青枯雷尔氏菌分布,说明青枯雷尔氏菌不仅可随植物蒸腾向上扩散,也可向下蔓延。     

陕西关中地区花卉植物根结线虫调查

对300种植物的调查表明:其中9科11种植物有根结线虫为害。对受害严重的5种植物病原线虫进行了鉴定。观赏石榴(Punica granatum var.nigra Hort.)被南方根结线虫(Meloidogyne incognita)为害;连翅(Forsythia suspensa)、雀舌黄杨(Buxus bodinieri)被北方根结线虫(M.hapla)和花生根结线虫(M.arenaria)为害;紫珠(Callicarpa dichotoma)、豆瓣黄杨(Buxus sinica)被北方根结线虫(M.hapla)为害。除连翅为国内北方新记录外,其它均为国内新记录。     

鸡J亚群白血病病毒与网状内皮增殖病病毒混合感染发病机理的研究

通过人工感染建立了ALV—J、REV单独感染和混合感染1日龄肉仔鸡的病理模型。初步研究表明混合感染使试验鸡的生长发育障碍、免疫器官萎缩、对细菌易感性及死亡率等指标显著升高。 动态病理学研究表明：REV感染主要引起骨髓网状细胞及淋巴样细胞弥漫性或灶状浸润,ALV—J感染主要引起骨髓髓系细胞灶状或弥漫性显著增生,混合感染时骨髓病变与REV感染基本一致,但相对较严重,并见ALV—J感染病变。各病毒感染组免疫器官均发生了严重的实质萎缩性病变,病变以混合感染组最重,REV组次之。在某些组织器官ALV—J组见嗜酸性粒细胞样的瘤细胞浸润增生,REV组见网状细胞及淋巴细胞样瘤细胞浸润增生,而混合感染组见以上两种瘤细胞增生。从混合感染组的病变来看,在致病性上ALV—J与REV之间的确存在明显的协同促进作用,导致机体的免疫抑制加重,但混合感染早期尚未发现REV对ALV—J致瘤的促进作用。     

斯氏线虫S.carpocapsae BJ对森林革蜱产卵量及其侵入部位的研究

用线虫浓度为8000 IJ/ml的斯氏线虫S.carpocapsae BJ品系侵染森林革蜱饱血雌蜱。实验期间统计饱血雌蜱的产卵量,用解剖镜观察线虫进入蜱体内的部位。结果表明,经线虫侵染后,平均每只蜱的产卵量为(327.0±11.0)个,而对照中每只蜱的产卵量为(4420.6±282.6)个;经线虫侵染后饱血雌蜱的死亡率高达90%。线虫的侵染使雌蜱的产卵量显著减少。线虫主要从蜱的口器、肛门、气门和生殖孔及节间膜处入侵。     

基于稻曲球结构分析稻曲菌的侵染部位和侵染时期

对田间采集的稻曲病病粒进行解剖分析,结果显示厚垣孢子层未形成的稻曲病病粒可分离出完整雌雄蕊;典型的稻曲球均可解剖出完整子房,且子房绿色未见明显膨大。雄性不育的水稻品系受稻曲病为害产生典型症状,其解剖结果与正常水稻品系相同。由此推测稻曲菌侵染水稻雌蕊发生在水稻开花之前,并直接从子房获得营养形成稻曲球。     

EffectS Of Synergism Between PVY and PVX on Vi rus Titer and Cell Ultrastructure in Tobacco Plants

The viruses titer and the ultrastructure of infected cells in tobacco host (Nicotiana tabacum cv.Samsun), which doubly infected with potato virus Y necrosis strain (PVYN) and potato virus X (PVX), were studied under greenhouse conditions. The results indicated that PVYN and PVX interacted synergistically, and tobacco plants which doubly infected with PVX and PVYN could greatly increase symptom severity as compared with that induced by the single virus. As determined by triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA), the titer of PVX in the tobacco leaves infected with both PVYN and PVX was up to 9.10 times higher than the plants infected with PVX only. No significant differences in PVYN titer were detected between singly and doubly infected plants. The enhancement of PVX titer in doubly infected plants was evident in greenhouse and was independent of the virus strains, tested seasons, intervals between PVYN and PVX inoculation. When sections of doubly infected leaves were examined with an electron microscope, it could be frequently found that cells contained pinwheels and large masses of PVX-like particles, pinwheels and laminate inclusions, or all three structures, most of them were swollen, and their chloroplast and other organella were destructed heavily. This suggested that doubly infected cells were involved in the enhancement phenomenon,which seemed to be the result of an increase in the amount of PVX synthesized in them.     

白粉病在小麦穗部的发生及穗叶抗性关系的研究

研究表明,随着小麦白粉病流行频率的提高,该病对小麦穗部的危害几乎与其对叶部的危害同等重要。供试的119个品种中,穗叶发病情况呈四种类型:I、穗叶均不发病;Ⅱ、穗病叶不病;Ⅲ、叶病穗不病;Ⅳ、穗叶均发病。以表现第Ⅳ类型的品种数最多,占95.8％。对表现第Ⅳ类型的品种穗叶病情资料所做的统计分析表明,穗部抗性与叶部抗性呈极显著的正相关(r=0.625)。     

PVY/PVX协生作用对病毒浓度及寄主细胞超微结构的影响

 以烟草品种三生烟 (N .tabacumcv .Samsun)为测试寄主 ,采用酶联免疫检测实验 (TAS ELISA)和电镜观察的方法 ,在温室条件下研究了马铃薯Y病毒 (PVY)和马铃薯X病毒 (PVX)复合侵染所引起的寄主症状和病毒浓度变化的特点、不同条件下复合侵染时病毒浓度的变化规律以及复合侵染对寄主细胞超微结构的影响。结果表明 ,PVY/PVX在烟草植株内发生了协生作用 ,PVY是协生病毒 ,PVX是被协生病毒。与单独侵染相比 ,PVY和PVX的复合侵染使烟草植株症状明显加重。PVY在复合侵染植株中的浓度与在单独侵染植株中相比 ,没有明显的变化 ,而PVX在复合侵染植株中的浓度明显高于在单独侵染植株中的浓度。这种现象不受PVY株系、处理季节和接种次序的影响。但是 ,不同PVY株系、不同处理季节或不同接种次序对PVY/PVX协生作用中PVX浓度的影响程度存在着一定的差异。电镜观察表明 ,与不接种病毒或单独侵染的植株相比 ,受复合侵染的烟草叶片细胞超微结构发生了明显的病理学变化。细胞肿胀 ,叶绿体、线粒体等细胞器受到严重损伤 ,细胞质内有风轮状、薄片状的内含体 ,由于在细胞质中常常有大量纤维状的PVX病毒粒子聚集体存在 ,这意味着PVX浓度的增加可能是在复合侵染的细胞中病毒大量繁殖的结果。     

华山松对蚜虫及螨侵害产生的生化响应

对受蚜虫侵害的华山松根、茎、叶的生化指标进行测定，并与正常华山松各指标对照，结果得出：华山松受蚜虫或螨类侵害后，其含糖量、酚类物质含量比正常华山松低；过氧化物酶和多酚氧化酶活性都比正常华山松高。受侵害的华山松与正常植株同一器官相比较，叶和根的变化较大，茎的变化较小。