Host preferences of phlebotomine sand flies at a hypoendemic focus of canine leishmaniasis in central Italy

A survey was carried out on phlebotomine sand flies and their feeding habits at a hypoendemic focus of Leishmania infantum in Macerata province, central Italy. During two consecutive years (2000-2001), 1465 sand fly specimens (42.5% of which were males) were collected from a variety of diurnal resting sites in the municipality of Camerino. The most prevalent species was Phlebotomus perniciosus (76.6%), followed by P. papatasi (10.4%), Sergentomyia minuta (9.1%), Phlebotomus perfiliewi (3.3%) and P. mascittii (0.5%). Among the 842 females collected, 578 (68.6%) were blood-fed. Based on the results of blood meal analyses, P. perniciosus fed on man, dogs, equines, sheep and birds; P. perfiliewi on dogs, equines, sheep and birds; P. papatasi on dogs, equines and birds. Two specimens of P. mascittii fed on equines. Forage ratios (FRs) and host selectivity indices gave different results for the large domestic animals. More than 95% of the specimens collected inside a stable, dog kennel, sheep pen and chicken house were found to have fed on the animals housed in the respective shelters. In addition, at one collecting site where almost all the hosts mentioned above were present simultaneously, both P. perniciosus and P. perfiliewi were found to have fed on all five species, indicating that host choice was probably related to its availability (i.e. number and size) rather than specific attractiveness. The feeding habits of the two Leishmania vectors may have implications for the epidemiology of leishmaniasis in urban and peri-urban areas, where sand fly females deprived of other vertebrate hosts (particularly the larger species) may begin to bite humans and dogs more frequently.     

多顺反子腺病毒表达载体PCA13/FasL-IRES-iNOS的构建和鉴定

背景：腺病毒具有免疫原性，可被机体快速免疫清除，导致目的基因失去表达，这是其作为基因治疗载体的主要缺陷。一些特定的细胞，如角膜上皮细胞和睾丸Sertoli细胞能表达和分泌Fas配体(FasL)，诱导带有Fas分子的免疫细胞发生凋亡。目的：构建FasL和诱导型一氧化氮合酶(iNOS)共表达PCA13质粒用于腺病毒的包装，以进一步观察FasL对腺病毒载体的免疫保护作用。方法：利用内源性核糖体进驻位点(IRES)，通过感受态细胞的制备和转化、质粒抽提、琼脂糖凝胶电泳以及限制性内切酶等多种基因工程技术，经多步亚克隆后完成能同时表达：FasL和iNOS基因的多顺反子腺病毒表达载体PCA13／FasL-IRES-iNOS的构建。结果：新质粒PCA13／FasL-IRES-iNOS经限制性内切酶酶切后得到1600bp(600bp FasL，1000bp IRES)和4000bp(iNOS)的相应基因片断，基因序列经测定与基因文库报道相符。结论：成功构建了多顺反子腺病毒表达载体PCA13／FasL-IRES-iNOS，为门脉高压症的基因治疗打下了基础。     

腺相关病毒载体转导基因至愈合肌腱及载体组织反应的研究

目的 探讨腺相关病毒(AAV)载体转导碱性成纤维细胞牛长因子(bFGF)基因对肌腱愈合的影响,并观察腺病毒、AAV以及脂质体一质粒三种基因治疗载体应用于肌腱所产生的组织反应.方法 取13只成年白色来亨鸡的双侧巾趾趾深屈肌腱(26根),随机分为实验组和对照组,每组13根,实验组肌腱完全切断后注射AAV2-bFGF并以改良Kessler法修复,对照组不注射AAV2-bFGF,仪以改良Kessler法修复.第4周未行免疫组织化学染色,第8周术测定趾屈曲功.将6只成年新西兰白兔的趾深屈肌腱(36根)分成二组,每组12根,分别注射10μL的腺病毒、AAV2和脂质体.质粒载体,术后第3、7、14天分别取肌腱,进行石蜡切片、HE染色.结果 AAV2-bFGF可以在术后4周显著地提高肌腱bFGF的表达,而且不增加趾屈曲阻力(粘连形成).所测屈曲功第8周末实验组为(0.052±0.031)J,对照组为(0.049±0.035)J,两组问差异无统计学意义(t=0.31266,P=0.8984).脂质体-质粒载体组肌腱组织反廊重于腺病毒载体组,AAV2载体组肌腱组织反应最轻,在腱外膜处有组织反应,而腱内膜区域几乎无组织反应.结论 用AAV2载体转bFGF基因至肌腱能有效增加愈合肌腱的bFGF.在三种所研究的载体中,腺病毒和AAV2载体引起的组织反应比脂质体.质粒载体轻.AAV2引起的组织反应最轻.AAV2可能会成为肌腱的转基因良好载体.     

慢病毒载体表达外源PON1对小鼠巨噬细胞的影响

目的:为探讨对氧磷酯酶1(PON1)在机体代谢性疾病中的作用及机制,本实验构建含人源性PON1基因的慢病毒表达载体,研究其表达分泌PON1的能力及对小鼠巨噬细胞的影响。方法:根据人肝cDNA文库的PON1序列设计特定引物,定点诱变PCR获得两端为PmeⅠ内切酶位点的目的基因,经酶切连接到pWPI-GFP载体上,筛选及DNA测序鉴定。磷酸钙法瞬时转染293T细胞,荧光显微镜观察GFP表达反映转染效率,Western Blotting检测细胞培养基中PON1分泌表达量,采用对氧磷为底物检测PON1活性。含PON1的培养基与小鼠腹腔巨噬细胞共孵育,ELISA法检测氧化条件下细胞分泌肿瘤坏死因子α(TNF-α)、白细胞介素-6(IL-6)的水平。结果:构建的pWPI-PON1慢病毒表达载体序列正确,高效转染293T细胞(转染效率可达到80%-90%)可有效分泌表达PON1至培养基,显著提高培养基PON1活性,与对照组相比,培养基中PON1可明显抑制巨噬细胞炎症因子TNF-α、IL-6的分泌(P<0.01)。结论:pWPI-PON1慢病毒载体高效表达分泌的外源PON1能有效降低巨噬细胞的炎症反应。     

靶向载脂蛋白M基因小干扰RNA表达载体构建及其功能

目的设计和构建载脂蛋白M基因特异性的小干扰RNA体内表达载体,筛选抑制载脂蛋白M表达的有效小干扰RNA,并初步探讨载脂蛋白M的功能。方法以载脂蛋白M为目的基因,以产生小干扰RNA质粒载体pSilencerTM2.1-U6为表达模板,细胞内转录合成4条小干扰RNA,并构建携带荧光素酶报告基因的重组质粒载体plucF-载脂蛋白。将重组质粒载体plucF-载脂蛋白与产生小干扰RNA的质粒pSilencerTM2.1-U6共转染293T细胞,定量测量荧光素酶活性,初步筛选出抑制荧光素酶表达的有效小干扰RNA,然后将小干扰RNA转染L-02,逆转录聚合酶链反应检测载脂蛋白M mRNA的表达,进一步证实小干扰RNA对载脂蛋白M表达的抑制效果,酶联免疫吸附法检测有效小干扰RNA对载脂蛋白AⅠ、载脂蛋白B和载脂蛋白E合成和分泌的影响。结果合成的4条小干扰RNA中有2条抑制荧光素酶表达,抑制效率分别为86%和91%,并特异性抑制肝细胞载脂蛋白M mRNA的表达;有效小干扰RNA能够有效抑制载脂蛋白AⅠ合成和分泌(P<0.05),而载脂蛋白B和载脂蛋白E的含量无明显改变(P>0.05)。结论成功构建并筛选到针对载脂蛋白M基因表达的有效小干扰RNA质粒,为研究冠心病的发病机制奠定基础。     

东营地区常见病媒生物生态习性研究

目的通过开展鼠类、蝇类、蚊类和蜚蠊类等常见病媒生物生态学研究,为科学控制提供依据。方法选择不同生境分别采用夹夜法、捕蝇笼、CO2紫外线灯诱和粘蟑板诱捕法对鼠类、蝇类、蚊类和蜚蠊类进行全年连续性监测,将捕获的病媒生物鉴定分类,计算密度,从中发现其生态规律。结果调查发现,居民区和畜牧养殖厂主要分布褐家鼠和小家鼠,农田中主要以黑线姬鼠、小仓鼠和小家鼠为主,其构成比分别为58.3%、25.0%和16.7%。蝇类密度监测表明,该地区家蝇和丝光丽蝇为优势种类,与其它蝇类的构成比为70%以上,有明显季节高峰。蚊类结果显示,淡色库蚊占整个蚊种的90%以上,刺扰伊蚊、三带喙库蚊和中华按蚊也占有较大的比例,其它蚊种很少。蜚蠊类监测结果显示,本地区德国小蠊为优势种类,蜚蠊类的季节消长与气温关系密切,本地区全年均可发现蜚蠊,7～9月份为高峰季节。结论不同鼠类在不同生态环境发生量不同,这与鼠类的个体差异和生态习性有关。蝇类发生量与温度、湿度和降雨量密切相关,不同季节表现出不同种的蝇类优势种群。淡色库蚊为当地的优势种群,也是入室骚扰吸血的主要蚊种。德国小蠊为当地蜚蠊主要种类,在室内温度满足的条件下可以全年发生和活动。     

鼠疫自然疫源地构成成分及其作用分析

摘要:鼠疫是由鼠疫耶尔森菌引起的一种发病急、传染性强、病死率高的自然疫源性疾病。鼠疫自然疫源地指在合适的地理景观条件下,由鼠疫耶尔森菌、宿主、媒介在长期的共同进化中相互适应而形成的特殊生态系统。研究鼠疫自然疫源地的构成成分及其作用,对了解鼠疫自然疫源地性质和结构,维持鼠疫生态系统平衡,有效预防和控制鼠疫疫情有着重要意义。     

慢病毒载体在基因工程中的应用

慢病毒载体可有效转导分裂和非分裂的细胞,将大型基因片段插入宿主细胞染色质并维持长期稳定的转基因表达,是应用广泛的基因转移载体.此文对慢病毒载体的发展及其在基因治疗、诱导多能干细胞、细胞成像、转基因动物及动物模型等基因工程方面的应用进行综述.     

2007年中蒙联合鼠疫宿主动物及媒介调查

〔目的〕通过对中蒙两国部分鼠疫自然疫源地地区鼠疫宿主动物及媒介昆虫联合调查,了解中蒙存在鼠疫宿主多样性的情况,以便分析鼠疫流行的潜在危险性,为进一步监控疫情和应对鼠疫突发卫生事件提供依据;同时为进一步掌握疫源地鼠疫宿主动物和媒介的演变规律提供数据。〔方法〕采用单公顷一日弓形夹法、5m夹线法和枪击方式捕获啮齿动物,对捕获的啮齿动物进行检蚤和检测,并探洞采集洞干蚤,分类鉴定,统计分析。〔结果〕中蒙相应调查地区鼠疫宿主动物和媒介种类及多样性存在较大差别。〔结论〕毗邻国家检疫部门、防疫单位和科研部门应紧密配合,互相协作,扩大合作领域,以促进揭开鼠疫进化演变奥秘的步伐。     

Ecological questions concerning rickettsiae

The past ten years were characterized by the appearance of several new transmissible spotted fever group (SFG) rickettsioses, e.g. Israeli, Japanese and Astrakhan fevers. The factors responsible for their establishment probably include the introduction of chemicals from industry, agriculture and the timber industry into natural habitats. Such factors may influence the pathogenicity of these rickettsiae. In this case, in addition to the human influence, the mechanism of the circulation of the agents under natural conditions of both abiotic (climate, etc.) and biotic (flora and fauna) components may play a decisive role. The modern management of breeding domestic animals, indoor and outdoor maintenance, seasonal migrations, new animal foods, stress, etc., can be important factors affecting the biological properties of the Q fever agent. Nonpathogenic rickettsiae, rickettsia-like symbionts and other microorganisms circulating in nature may also influence the pathogenic rickettsiae. Studies on their interrelationships in hosts and vectors may markedly contribute to the understanding of the circulation of pathogenic rickettsiae in nature. Recognition of factors causing the appearance of new rickettsial agents or differences in pathogenicity of rickettsial strains is important not only for the prognosis of rickettsial diseases but also for the prognosis of other infectious diseases.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Disease, Pietany, C.S.F.R., 1–6 October, 1990.