靶向表达的逆转录病毒载体LN.ALBTRS.TK的构建

目的构建出在肝细胞中具靶向表达潜能的逆转录TK基因载体。方法用p2335A-1中的一段2.0kb的人白蛋白组织特异性转录调节序列(ALBTRS)取代pSTK中的SV40启动子,所构建的载体命名为LN.ALBTRS.TK。结果载体LN.ALBTRS.TK的结构中,含有ALBTRS启动子,具有在表达白蛋白的肝细胞中特异表达的潜能,载体经酶切鉴定表明结构符合要求。结论成功地构建出具靶向表达潜能的逆转录载体LN.ALBTRS.TK。     

Malaria vector control strategies. What is appropriate towards sustainable global eradication?

Malaria a mosquito-borne disease caused by Plasmodium remains to be a main global burden despite concerted efforts to eliminate it. While diverse control strategies have been put in place for mosquito-borne diseases, vector control continues to be a critical component in infection prevention. Vector control majorly focuses on the eradication of mosquitoes using a variety of chemical insecticides that includes organochlorides, carbamates, organophosphates, and pyrethroids. The use of conventional insecticide-based as mosquito control strategies poses several challenges such as the widespread development of insecticide resistance, environmental damage concerns, and effects on non-target organisms. These challenges create a demand for the development and use of alternative pest control strategies that are sustainable, safer, and environmentally friendly to mosquito vector management. This review provides insight into alternative sustainable interventions for mosquito vector control in the form of biorational pesticides. Biorational pesticides are pesticides that have little or no effect on humans and environments and include entomopathogenic microorganisms, insect growth regulators, and endosymbiotic bacteria. It also puts into perspective their environmental impacts, benefits, and challenges. Further, countries like Sri Lanka, that are certified as malaria free by World Health Organization (WHO) incorporated the use of entomopathogenic bacteria, insect growth regulators and larvivorous fish in their national vector control programs leading to the successful elimination of malaria in 2016. We therefore highlight success stories of the countries that have implemented these interventions bringing out the lessons for countries that are battling malaria epidemics.     

扩张型心肌病患者左心室能量损耗及室壁剪应力的血流向量成像评价

目的应用血流向量成像（VFM）技术定量评估扩张型心肌病（DCM）患者的左心功能异常。 方法选取2019年1月至2019年4月于武汉亚洲心脏病医院确诊DCM的患者29例为DCM组,同期匹配健康志愿者32例为对照组。VFM模式下获取两组心尖四腔心、三腔心切面二维彩色多普勒血流动态图,脱机分析对比不同切面等容收缩期（P0）、快速射血期（P1）、等容舒张期（P2）、快速充盈期（P3）、心房收缩期（P4）能量损耗（EL）及各节段室壁剪应力（WSS）平均值的差异,评估DCM患者左心室血流动力学的改变。 结果与对照组相比,DCM组在P0、P1及P3期EL均减低［分别为（2.24±1.33）J/（s·m³）vs（1.39±0.49）J/（s·m³）、（6.14±3.58）J/（s·m³）vs（4.17±2.12）J/（s·m³）、（10.38±6.67）J/（s·m³）vs（4.92±2.73）J/（s·m³）,均P＜0.05］。DCM组左心室壁在P0期基底段［（0.45±0.30）N/m² vs（0.23±0.13）N/m²］,P1、P2期基底段和中间段［分别为（1.24±0.39）N/m² vs（0.93±0.40）N/m²、（0.55±0.30）N/m² vs（0.36±0.23）N/m²,（0.29±0.08）N/m² vs（0.12±0.05）N/m²、（0.14±0.08）N/m² vs（0.10±0.06）N/m²］,P3期各节段［分别为（0.60±0.24）N/m² vs（0.26±0.08）N/m²、（0.47±0.29）N/m² vs（0.14±0.04）N/m²、（0.13±0.06）N/m² vs（0.06±0.02）N/m²］以及P4期基底段［（0.40±0.15）N/m² vs（0.25±0.12）N/m²］的WSS较对照组均减低（均P＜0.05）。对照组WSS同一时相呈现基底段＞中间段＞心尖段,而DCM组P0、P2和P4期基底段与中间段WSS差异无统计学意义（均P＞0.05）。对照组WSS同一节段P0→P1→P2→P3→P4期表现为升高－减低－升高－减低改变（均P＜0.05）,而DCM组WSS仅基底段P0→P1→P2→P3期表现为升高－减低－升高趋势（均P＜0.05）,余节段WSS在各时相间变化差异均无统计学意义（均P＞0.05）。 结论VFM技术中的EL及WSS作为新的血流动力学量化参数,可评估DCM患者左心室功能异常。     

Trypanosoma cruzi infection in Triatoma sordida before and after community-wide residual insecticide spraying in the Argentinean Chaco

Triatoma sordida is a secondary vector of Trypanosoma cruzi in the Gran Chaco and Cerrado eco-regions where it frequently infests peridomestic and domestic habitats. In a well-defined area of the humid Argentine Chaco, very few T. sordida were found infected when examined by optical microscopic examination (OM). In order to further assess the role of T. sordida and the relative magnitude of subpatent bug infections, we examined the insects for T. cruzi infection, parasite Discrete Typing Units (DTUs) and bloodmeal sources using various molecular techniques. Among 205 bugs with a negative or no OM-based diagnosis, the prevalence of infection determined by kDNA-PCR was nearly the same in bugs captured before (6.3%) and 4 months after insecticide spraying (6.4%). On average, these estimates were sixfold higher than the prevalence of infection based on OM (1.1%). Only TcI was identified, a DTU typically associated with opossums and rodents. Chickens and turkeys were the only bloodmeal sources identified in the infected specimens and the main local hosts at the bugs’ capture sites. As birds are refractory to T. cruzi infection, further studies are needed to identify the infectious bloodmeal hosts. The persistent finding of infected T. sordida after community-wide insecticide spraying highlights the need of sustained vector surveillance to effectively prevent T. cruzi transmission in the domestic and peridomestic habitats.     

First overview of the Culicoides Latreille (Diptera: Ceratopogonidae) livestock associated species of Reunion Island,Indian Ocean

This study establishes the first faunistic inventory of livestock associated Culicoides (Diptera: Ceratopogonidae) species of Reunion Island (Indian Ocean), where bluetongue and epizootic hemorrhagic disease are regularly recorded. Single night-catches were performed at 41 sites using light suction traps at altitudes ranging from 0 to 1525 m, from March to April 2005. Five species were recorded: Culicoides imicola, Culicoides bolitinos, Culicoides enderleini, Culicoides grahamii, and Culicoides kibatiensis, among which at least the first three species are known to be involved in virus transmission to ruminants and equids. This is the first record of C. bolitinos, C. kibatiensis, and C. enderleini on the island. C. imicola was the most abundant species along the sea coast. C. bolitinos was more abundant inland and on two sites on the east coast. C. kibatiensis and C. grahamii were less abundant than the other three species and limited to two foci.     

促血管生成素-1基因重组腺病毒载体的构建及鉴定

目的构建携带小鼠促血管生成素-1(Ang-1)基因的重组腺病毒载体并鉴定。方法化学合成小鼠Ang-1基因经PCR扩增后亚克隆至穿梭质粒,重组质粒转化感受态细胞,所得转化子经PCR电泳分析并测序鉴定,携带外源基因的腺病毒穿梭质粒与携带腺病毒大部分基因组的辅助包装质粒共转染人胚肾细胞系HEK 293细胞,反复冻融获取重组腺病毒,终点稀释法测定重组腺病毒滴度,所得腺病毒转染293T细胞48 h收集培养上清,通过Western Blot分析Ang-1蛋白的表达。结果 PCR产物电泳分析可见大小约1.5 kbp的特征性条带,测序结果显示基因序列与Gen Bank提供的Ang-1序列一致,经HEK293细胞包装后腺病毒滴度为1×109pfu/ml,转染293T细胞后培养上清Western Blot分析可见大小58 k D特征性条带,即转染后能分泌正确大小的重组Ang-1蛋白。结论 Ang-1基因重组腺病毒载体可成功构建,为进一步研究Ang-1蛋白对造血干细胞动员及血管新生的作用提供实验依据。     

Leishmania infantum DNA detection in Phlebotomus tobbi in a new northern focus of visceral leishmaniasis in Iran

Objective

To identify the vector(s), the parasite and the species composition of sand flies in the district during May-October 2012.

Methods

For reaching our objectives we used polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphism.

Results

Two species of Phlebotomus sergenti and Phlebotomus tobbi were the most prevalent among 8 species identified comprising 51.1% and 32.9% respectively. Among the 160 specimens of female sand flies tested by polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphisms, only 1 out of 80 Phlebotomus tobbi (1.25%) were positive to Leishmania infantum parasites.

Conclusions

Our finding showed that Phlebotomus tobbi may play as a vector to circulate the parasite of Leishmania infantum among reservoir(s) and human.     

Lessons learned from previous dengue outbreaks

Dengue is an important tropical infection caused by an arbovirus dengue. As a mosquito borne infection, this disease is widely spread in several tropical endemic countries. Millions of world populations are at risk for this arboviral infection. Each year, thousands of dengue infections are reported and there are several death cases. Each year, the outbreaks of dengue emerge in several countries and this implies the global importance of this infection. Fighting with dengue outbreak is important in public health. In this specific chapter, the author discussed lessons learned from previous dengue outbreaks.     

Evaluation of the mosquitocidal effect of Birbira (Mellitia ferruginea) seed extract against Anopheles arabiensis (Diptera: Culicidae) from Ethiopia

Mosquito control using insecticides has been the most successful intervention known to reduce malaria prevalence and/or incidence. However, over time success has been hampered due to the development of resistance by mosquitoes against chemical insecticides recommended for public health use. Development of effective botanical mosquitocidal compounds however can be potential alternatives tool in malaria vector control. Thus, the present study aimed at investigating the mosquitocidal effect of “Birbira” (Mellitia ferruginea) seed extract against the primary malaria vector, Anopheles arabiensis from Ethiopia. The mosquitocidal activity of M. ferruginea was assessed following WHO susceptibility test procedure. Methanol extract of M. ferruginea seeds was evaluated against third & fourth instar larvae, pupae and, non-blood fed 3–5 days old laboratory strains and field populations of A. arabiensis under laboratory condition. Mortality was then recorded after 24 h exposure. The seed extract of M. ferruginea showed high mosquitocidal activity against larvae, pupae and adult stages of both the laboratory strain and field population of A. arabiensis. The LC₅₀ values for larvae and pupae population from a laboratory strains was, respectively, 14.7 and 41.33 mg/L. While the LC₅₀ values for the larvae and a pupa of the field population were, respectively, 30.88 and 74.54 mg/L. In addition, the LC₉₉ and LD₉₉ values were also identified. The findings of this study indicated that, the extract could be applied on mosquito breeding sites. The plant extract could be also used for indoor residual sprays after conducting the persistency test.