利用siRNA高通量测序技术筛查蚊子体内携带的RNA病毒

昆虫可以利用小干扰RNA(siRNA)机制干扰体内RNA病毒的增殖,从而获得对该病毒的免疫能力。通过第二代测序技术对蚊子的小RNA进行高通量测序,再通过生物信息学方法寻找其中的RNA病毒序列,发现在我国云南地区的白纹伊蚊和致倦库蚊体内存在Marayo,Omsk hemorrhagic fever和Ilheus等RNA病毒的基因片段。至此建立了发现媒介昆虫体内携带病毒的一种新方法,可用于媒介昆虫携带RNA病毒的本底调查。     

白纹伊蚊溴氰菊酯抗性和敏感品系羧酸酯酶性质比较

本文对白纹伊蚊Aedes albopictus溴氰菊酯抗性品系和敏感品系羧酸酯酶的生物化学性质进行了比较。白纹伊蚊抗性品系和敏感品系羧酸酯酶随底物浓度(α-乙酸萘酯或β-乙酸萘酯)的变化比活力变化趋势一致,但抗性品系对这2种底物的比活力均高于敏感品系,抗性品系羧酸酯酶的米氏常数和最大反应速度与敏感品系有显著差异。胆碱酯酶抑制剂测定结果表明,抗性品系羧酸酯酶对敌敌畏和磷酸三苯酯的敏感性高于敏感品系,对残杀威的敏感性低于敏感品系。2个品系羧酸酯酶对脱叶磷的敏感性差异不大。说明羧酸酯酶可能与白纹伊蚊对溴氰菊酯抗性有关。     

几种驱避化合物对白纹伊蚊寄主搜寻能力的影响

研究了白纹伊蚊Aedes albopictus在含不同浓度的驱避化合物的空间内停留不同时间后,对其寄主搜寻能力的影响。结果显示：在密闭空间中, 分别以0.013～0.500 μg/cm³浓度的柠檬醛、丁香酚、芳樟醇、香叶醇、茴香醛处理白纹伊蚊24～96 h后,试蚊均出现不同程度的定向寄主抑制,其中以茴香醛及香叶醇抑制效果最佳,但香茅醛各处理组试蚊均未受到影响。白纹伊蚊搜寻定向寄主能力受到抑制的个体,在实验室正常饲养后,可逐渐恢复;但茴香醛0.250 μg/cm³处理试虫96 h后,一直未能恢复正常的吸血行为。研究结果提示,茴香醛与香叶醇作为优良的空间驱避剂,在白纹伊蚊防控技术领域可发挥重要作用。     

埃及伊蚊浓核病毒(AaeDV)对致倦库蚊的致病性研究

致倦库蚊(Culex quinquefasciatus)是西尼罗病毒(West Nile virus,WNV)、圣路易斯脑炎病毒等重要的媒介。蚊浓核病毒(Mosquito densovirus,MDV)是特异性感染蚊类的病毒,对蚊虫具有明显的致病性。为研究MDV对致倦库蚊的致病效应,我们使用不同浓度埃及伊蚊浓核病毒(Aedes aegypti densovirus,AaeDV)感染致倦库蚊不同发育阶段的幼虫、蛹与成蚊,测定其感染率与死亡率,结果证实AaeDV对致倦库蚊1~2龄幼虫、3~4龄幼虫、蛹和雌雄成蚊的感染率分别为93.33%±2.49%、66%±3.74%、2.67%±0.94%、23.33%±3.40%和24.00%±1.63%,感染率与其发育阶段有关而与性别无关。AaeDV对幼虫的杀伤效果具有剂量依赖性,且与发育阶段有关,在1×1011拷贝/mL浓度下,新孵化龄幼虫和3~4龄幼虫的死亡率高达95.33%±0.74%和61.67%±2.07%。因此AaeDV对致倦库蚊具有生物防制的潜在价值。     

我国蚊虫体内感染的Wolbachia的wsp基因序列测定与分析

测定了我国尖音库蚊复合组和白纹伊蚊蚊虫体内感染的Wolbachia株的wsp基因序列。核苷酸和氨基酸的同源性及系统关系分析表明,我国尖音库蚊复合组和白纹伊蚊中Wolbachia株的wsp基因序列与Pip组其它株的核苷酸及氨基酸同源性分别为98%～100%和97%～100%, 属B大组Wolbachia中的Pip组。     

从贵州白纹伊蚊体内分离到一株2型登革病毒

从贵州省独山县麻尾镇白纹伊蚊标本中分离到一株病毒,用抗DEN 14型单克隆抗体经间接免疫荧光法和RTPCR产物酶切分型鉴定为DEN2,并对其 NS1和E基因RTPCR产物进行部分基因序列测定,与DEN2 NGC株比较,麻尾株的NS1基因区有7个碱基发生点突变,E基因区有1个碱基的插入,两个序列被GenBank收录,编号分别为AY277402、AY278226;麻尾分离株与其他9株DEN2型病毒进行系统发育关系的分析,结果显示与D243株系统进化关系最近;证明贵州省存在DEN感染的自然循环。     

白纹伊蚊感染登革Ⅱ型病毒后的屏障

以高、低两种浓度病毒液分别经胸接种和经口感染海南株白纹伊蚊Aedes albopictus后,经不同时间内对蚊虫中肠、脑、神经节和涎腺进行IFA染色检查.比较各器官感染率后可知该蚊存在中肠感染屏障(mesenteronal infection barrier MIB)、中肠释放屏障(mesenteronal escape barrier,MEB)和涎腺感染屏障(salivary gland infection barrier,SGIB)并且各屏障率分别与时间及剂量呈负相关.     

Evaluations of larvicidal activity of medicinal plant extracts to Aedes aegypti （Diptera： Culicidae） and other effects on a non target fish

A preliminary study was conducted to investigate the effects of the extracts of 112 medicinal plant species, collected from the southern part of Thailand, on Aedes aegypti. Studies on larvicidal properties of plant extracts against the fourth instar larvae revealed that extracts of 14 species showed evidence of larvicidal activity. Eight out of the 14 plant species showed 100% mosquito larvae mortality. The LC50 values were less than 100μg/mL （4.1μg/ mL-89.4μg/mL）. Six plant species were comparatively more effective against the fourth instar larvae at very low concentrations. These extracts demonstrated no or very low toxicity to guppy fish （Poecilia reticulata）, which was selected to represent most common non-target organism found in habitats ofAe. aegypti, at concentrations active to mosquito larvae. Three medicinal plants with promising larvicidal activity, having LC50 and LC50 values being 4.1 and 16.4 μg/mL for Mammea siamensis, 20.2 and 34.7 μg/mL forAnethum graveolens and 67.4 and 110.3μg/mL forAnnona muricata, respectively, were used to study the impact of the extracts on the life cycle ofAe. aegypti. These plants affected pupal and adult mortality and also affected the reproductive potential of surviving adults by reducing the number of eggs laid and the percentage of egg hatchability. When each larval stage was treated with successive extracts at the LC50 value, the first instar larvae were found to be very susceptible to A. muricata and the second instar larvae were found to be susceptible to A. graveolens, while the third and fourth instar larvae were found to be susceptible to M. siamensis. These extracts delayed larval development and inhibited adult emergence and had no adverse effects on P. reticulata at LC50 and LC50 values, except for the M. siamensis extract at its LC50 value.     

基孔肯雅热

基孔肯雅热(Chikungunya fever,CHIK)是由基孔肯雅病毒(Chikungunya virus,CHIKV)病毒引起的,伊蚊叮咬传播的,以发热、关节疼痛等为主要特征的自限性传染性疾病。1952年在坦桑尼亚发生的暴发流行中首次分离CHIKV[1-2],亚洲地区于