我国常见蜱的生物学特性及其传播疾病研究进展

蜱是以吸食动物血液为生的寄生生物,可以传播多种病原体,引起宿主患病。我国蜱种多样,分布广泛,多种蜱具有医学重要性。现就我国常见蜱种的生物学特性及其可传播疾病作一综述。     

Larval membrane antigens protect Hereford cattle against infestation with Boophilus microplus

Hereford cattle (Bos taurus) were immunized with antigens solubilized with Triton X-100 from larval membranes of the cattle tick (Boophilus microplus). Based on tick egg production compared to control cattle, vaccinated cattle were protected (78%) against challenge with 2 x 20,000 tick larvae. The soluble Triton X-100 extract of tick larval membranes was further purified by immunoaffinity chromatography, using immunoglobulin ligands (IgG1 and IgG2) from three immune steers, previously vaccinated with membrane antigens from the midgut of partly engorged adult female ticks. Cattle vaccinated with these purified antigens were protected in two separate experiments (80 and 89% respectively), against challenge with 2 x 20,000 larval ticks compared to control cattle. Whole larval membranes used as vaccines in cattle reduced the amount of eggs produced from ticks by 47% compared to control cattle, but this difference was not significant.     

长角血蜱和微小扇头蜱的形态与分子生物学鉴定

目的 建立鉴定长角血蜱和微小扇头蜱的形态学和分子生物学相结合的方法.方法 采集自湖北和河南省布尼亚新病毒疫区家养动物体表寄生的蜱及草丛、灌木中的蜱;先以形态学鉴定,后用PCR方法扩增得到蜱的12S rDNA,测序后进行同源性和系统进化分析.结果 形态学方法鉴定采集到两种蜱:长角血蜱(Haemaphysalis longicornis)和微小扇头蜱(Rhipicephalus microplus).蜱的12S rDNA经克隆、测序,用PAUP 4.0软件构建系统发生树,湖北、河南省两种蜱的12S rDNA序列分别与长角血蜱和微小扇头蜱聚类,与形态学鉴定结果一致.结论 在传统形态学分类的基础上结合分子生物学鉴定方法能更准确地鉴定蜱的种类.     

中华硬蜱和微小牛蜱不同发育阶段蛋白质、糖、脂的比较研究

本文应用盘状电泳方法对中华硬蜱和微小牛蜱不同发育阶段的蛋白质、糖、脂进行了比较研究。结果表明,两种不同属种硬蜱的成虫、幼虫和虫卵的蛋白质、糖、脂电泳图谱都有明显差别;两种硬蜱各自的不同发育阶段的蛋白质、糖、脂电泳图谱也具有明显差异。     

Immunoglobulin G binding proteins in male Rhipicephalus appendiculatus ticks

Three abundant immunoglobulin G binding proteins (IGBPs) of29kDa (IGBP-MA), 25kDa (IGBP-MB), and 21 kDa (IGBP-MC) were isolated from partly fed male Rhipicephalus appendiculatus ticks using an agar-ose-IgG column. After separating the proteins by SDS-PA GE, each individual IGBP band was cutou tfrom the gel and used to raise antiserum in guinea pigs. Using immuno-blotting, each of the three IGBPs was shown to be antigenically distinct, and specific for feeding male R. appendiculatus ticks. They were detected in the salivary glands of male ticks that had been feeding in either the presence of absence of female ticks, and appeared to be glycoproteins. The smallest protein, IGBP-MC, bound to guinea pig IgG (on which species the ticks were fed) and also bound to human and bovine IgG, whereas IGBP-MA and possibly IGBP-MB only bound to guinea pig IgG. The function of IGBPs in tick salivary glands and their significance in male ticks are discussed.     

Effect of salivary gland extracts from the tick,Boophilus microplus,on leucocytes from Brahman and Hereford cattle

The effect of salivary gland extract (SGE) from Boophilus microplus on peripheral blood lymphocytes, neutrophils and monocytes from Brahman (Bos indicus) and Hereford (Bos taurus) cattle was investigated. SGE (8 micro g) significantly inhibited the proliferation response of lymphocytes to concanavalin A from both Brahman and Hereford cattle by 89% and 41%, respectively. The difference in inhibition between the two breeds was highly significant (P < 0.01), whilst at 1 micro g of SGE, significant inhibition of lymphocytes occurred only in Hereford cattle (34%). Flow cytometric analysis of monocytes and neutrophils showed that SGE (40 micro g) significantly reduced both the proportion of cells actively phagocytosing Escherichia coli labelled with fluorescein isothiocyanate (E. coli-FITC) and the uptake of E. coli-FITC in Brahman cattle. However, in Hereford cattle, a significant depression in uptake was only observed in neutrophils. The proportion of monocytes and neutrophils with oxidative activity was significantly suppressed in the presence of SGE in both breeds of cattle. These results indicate that peripheral blood leucocytes from different breeds of cattle respond differently to SGE.     

室内饲养条件下三种硬蜱产卵和孵化特性的比较研究

目的:为了认识微小牛蜱和扇头蜱之间的关系。方法:在室内饲养条件下对微小牛蜱(Boophilusmi-croplus)、镰形扇头蜱指名亚种(Rhipicephalushaemaphysaloideshaemaphysaloides)和猛突血蜱(Haemaphysalismontgomeryi)的产卵和孵化特性进行了比较研究。结果:三种硬蜱在产卵期天数上差异不明显(p>0.05),而在孵化期上有极显著差异(p<0.01);微小牛蜱和镰形扇头蜱间除了吸血后体重(p<0.05)、产卵前期(p<0.01)、孵化期(p<0.01)外,其余参数均差异不明显(p>0.05);猛突血蜱与微小牛蜱间仅在产卵前期和产卵期天数上差异不显著(p>0.05),与镰形扇头蜱间仅在产卵期天数上差异不明显(p>0.05),其余各项参数间都有显著或极显著差异;猛突血蜱的生殖效率和孵化率均明显高于微小牛蜱和镰形扇头蜱(p<0.05)。此外,三种硬蜱不仅日产卵量曲线相似,而且产卵量与吸血后体重之间均存在着极显著的正相关关系(r>0.93,p<0.01)。结论:微小牛蜱和扇头蜱之间有较高的相似度。     

豫西地区莱姆病血清学及病原学研究

目的　了解豫西地区有关人群血清中是否存在抗莱姆病螺旋体抗体及可能存在的生物媒介。方法　采用间接或直接免疫荧光技术 ,对人血清相关抗体及蜱中肠带菌情况进行研究。结果　豫西地区人群中存在莱姆病自然感染 ,人群感染率为 13.5 3% ;蜱类调查显示 ,长角血蜱和微小牛蜱的中肠带菌阳性率为 2 6 .0 0 % ,这两种蜱可能为传播媒介 ;并从褐家鼠和黄胸鼠的血清中也检测到莱姆病抗体。结论　初步显示豫西地区存在莱姆病疫源地。     

镰形扇头蜱半饱血雌蜱cDNA文库的构建

目的 为了筛选抗蜱及蜱传疾病基因工程疫苗的抗原候选分子,构建了镰形扇头蜱半饱血雌蜱cDNA表达文库。方法 用Frizol试剂提取镰形扇头蜱半饱血雌蜱总RNA,经反转录合成cDNA第一链,应用长链PCR(LD-PCR)扩增方法,合成双链cDNA。双链cDNA(ds cDNA)在Sfi I内切酶的作用下,形成两端分别带有Sfi I A和Sfi I B的粘性末端。经CHROMA SPIN-400柱纯化,收集500bp以上的双链cDNA片段,将其连接于带有Sfi工A和Sfl I B末端的λTriplEx2噬菌体载体,经体外包装后,以XL1-Blue为受体菌构建cDNA噬菌体表达文库。结果 经测定,库容量为4.2×106,重组率为96％。扩增后的文库滴度为2.04×1010pfu/ml。通过对文库中随机挑选的15个克隆进行序列分析,获得一个编码线粒体ATP酶第6亚基蛋白的全长cDNA序列。结论 结果显示,镰形扇头蜱半饱血雌蜱cDNA表达文库已构建成功。