温度对斯氏按蚊传疟能力的影响及分子机制初探
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摘要
目的研究环境温度对按蚊传疟能力的影响,并通过比较分析不同温度下斯氏按蚊天然免疫关键分子TEP1转录水平,初步探讨相关分子机制,为气候变化对疟疾传播和流行的影响提供理论依据。方法本研究利用斯氏按蚊-约氏疟原虫动物模型,分别在24℃和28℃的环境温度下利用约氏疟原虫感染斯氏按蚊,感染后9 d解剖蚊中肠,荧光显微镜下观察疟原虫卵囊发育情况并计数,比较不同温度条件下疟原虫感染率和感染度。然后,利用荧光定量PCR方法比较不同温度条件下,感染前后不同时间点的斯氏按蚊TEP1分子的转录水平。结果在24℃的环境温度下,斯氏按蚊的感染率为91.7%,感染度为(403.9±37.09)个/蚊。在28℃的环境温度下,斯氏按蚊的感染率为38.8%,感染度为(38.63±13.91)个/蚊。24℃组的按蚊感染率和感染度均显著高于28℃组(P<0.001)。于吸血感染当天但尚未吸血时和吸血感染疟原虫后的第5天、第7天及第9天,斯氏按蚊的TEP1转录水平在28℃的条件下均高于24℃,提示斯氏按蚊TEP1参与的感染前基础免疫力和疟原虫感染中后期的免疫杀伤力28℃组均高于24℃组。结论环境温度对按蚊传疟能力的影响较大,24℃较28℃的环境更适宜于约氏疟原虫感染斯氏按蚊;TEP1参与的天然免疫反应可能是温度对按蚊传疟能力影响的原因和分子机制之一。
Objective To study the impact of ambient temperature on the vector competence of Anopheles stephensi to malaria parasites, and to preliminarily investigate the related molecular mechanism by comparative analysis of the transcriptional level of TEP1, a key molecule of Anopheles stephensi innate immunity at different temperatures, which will provide a theoretical reference for the impact of climate change on transmission and epidemic of malaria.Methods Animal model of Anopheles stephensi-Plasmodium yoelii was used in this study. Anopheles stephensi was infected by Plasmodium yoelii at 24 ℃ and 28 ℃, respectively. The midgut of Anopheles stephensi was dissected 9 days after infection. The development of the oocysts of Plasmodium yoelii was observed and counted under fluorescence microscope and the infection rates and densities under different temperature conditions were compared. Then, the transcriptional levels of TEP1 of Anopheles stephensi at different time points before and after infection were compared between 24 ℃ and 28 ℃ groups by Real-time PCR.Results The infection rate and density of Anopheles stephensi were 91.7% and(403.9 ± 37.09)/mosquitoat 24 ℃, and 38.8% and(38.63± 13.91)/mosquitoat 28 ℃, respectively. Both the infection rate and density were significantly higher at 24 ℃ than those at 28 ℃(P < 0.001). The transcriptional level of Anopheles stephensi TEP1 at 28 ℃ was higher than that at 24 ℃ before blood feeding and on day 5, day 7 and day 9 post blood feeding. It indicated that the TEP1 involved basal immunity before infection and immune killing ability in the mid to late period post infection was higher at 28 ℃ than 24 ℃.Conclusion Ambient temperature has a great impact on the vector competence of Anopheles stephensi to malaria parasites. And the environment of 24 ℃ is more suitable than 28 ℃ for the transmission of Anopheles stephensi to Plasmodium yoelii. The TEP1 involved immune response is probably one of the cause and molecular mechanism of the impact of temperature on the vector competence of Anopheles stephensi to malaria parasites.
Objective To study the impact of ambient temperature on the vector competence of Anopheles stephensi to malaria parasites, and to preliminarily investigate the related molecular mechanism by comparative analysis of the transcriptional level of TEP1, a key molecule of Anopheles stephensi innate immunity at different temperatures, which will provide a theoretical reference for the impact of climate change on transmission and epidemic of malaria.Methods Animal model of Anopheles stephensi-Plasmodium yoelii was used in this study. Anopheles stephensi was infected by Plasmodium yoelii at 24 ℃ and 28 ℃, respectively. The midgut of Anopheles stephensi was dissected 9 days after infection. The development of the oocysts of Plasmodium yoelii was observed and counted under fluorescence microscope and the infection rates and densities under different temperature conditions were compared. Then, the transcriptional levels of TEP1 of Anopheles stephensi at different time points before and after infection were compared between 24 ℃ and 28 ℃ groups by Real-time PCR.Results The infection rate and density of Anopheles stephensi were 91.7% and(403.9 ± 37.09)/mosquitoat 24 ℃, and 38.8% and(38.63± 13.91)/mosquitoat 28 ℃, respectively. Both the infection rate and density were significantly higher at 24 ℃ than those at 28 ℃(P < 0.001). The transcriptional level of Anopheles stephensi TEP1 at 28 ℃ was higher than that at 24 ℃ before blood feeding and on day 5, day 7 and day 9 post blood feeding. It indicated that the TEP1 involved basal immunity before infection and immune killing ability in the mid to late period post infection was higher at 28 ℃ than 24 ℃.Conclusion Ambient temperature has a great impact on the vector competence of Anopheles stephensi to malaria parasites. And the environment of 24 ℃ is more suitable than 28 ℃ for the transmission of Anopheles stephensi to Plasmodium yoelii. The TEP1 involved immune response is probably one of the cause and molecular mechanism of the impact of temperature on the vector competence of Anopheles stephensi to malaria parasites.
引文
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[12]于莎莎,王英,李秋霞,等.大劣按蚊卵黄蛋白原cDNA的克隆及转录水平研究[J].中国热带医学,2017,17(4):336-339.
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[14]MURDOCK C C,BLANFORD S,LUCKHART S,et al.Ambient temperature and dietary supplementation interact to shape mosquito vector competence for malaria[J].J Insect Physiol,2014,67:37-44.
[15]CLAYTON A M,DONG Y M,DIMOPOULOS G.The Anopheles innate immune system in the Defense against malaria infection[J].J Innate Immun,2014,6(2):169-181.
[16]SHOKAL U,ELEFTHERIANOS I.Evolution and function of thioester-containing proteins and the complement system in the innate immune response[J].Front Immunol,2017,8:759.
[17]王英,黄复生.疟原虫在蚊体内发育及蚊抗疟原虫感染的分子机制[J].国际医学寄生虫病杂志,2007,35(4):202-207.
[18]LUNDE T M,BAYOH M N,LINDTJ?RN B.How malaria models relate temperature to malaria transmission[J].Parasit Vectors,2013,6:20.
[2]WANG D Q,LI S G,CHENG Z B,et al.Transmission risk from imported plasmodium vivax malaria in the China-myanmar border region[J].Emerging Infect Dis,2015,21(10):1861-1864.
[3]ZHOU G F,SUN L,XIA R J,et al.Clinical malaria along the Chinamyanmar border,Yunnan province,China,january 2011-august2012[J].Emerging Infect Dis,2014,20(4):675-678.
[4]杨恒林,肖宁,杨亚明,等.中缅和中老边境地区消除疟疾的挑战、机遇与对策[J].中国热带医学,2017,17(4):321-324,335.
[5]MURRAY C J,ROSENFELD L C,LIM S S,et al.Global malaria mortality between 1980 and 2010:A systematic analysis[J].Lancet,2012,379(9814):413-431.
[6]滕卫平,俞善贤,胡波,等.气候变化对中国疟疾传播范围与强度的影响[J].科技通报,2013,29(7):38-42.
[7]王伟明,李菊林,周华云,等.不同温度条件对中华按蚊发育的影响[J].中国血吸虫病防治杂志,2010,22(3):260-263.
[8]刘体亚,石敏,刘林,等.疟疾与气候因素关系的分析[J].中华全科医学,2011,9(4):604-605,608.
[9]金浩,姚宝龙.气候变化对疟疾流行特征影响的研究进展[J].国际医学寄生虫病杂志,2011,38(2):110-112.
[10]胡晓飞,姜晓梅,谢佳,等.TEP1分子在蚊天然免疫中的研究进展[J].中国病原生物学杂志,2009,4(1):59-61.
[11]于莎莎,王英,艾国平.TEP1分子在按蚊抗疟原虫感染中作用机制的研究进展[J].热带病与寄生虫学,2013,11(3):178-180.
[12]于莎莎,王英,李秋霞,等.大劣按蚊卵黄蛋白原cDNA的克隆及转录水平研究[J].中国热带医学,2017,17(4):336-339.
[13]BECK-JOHNSON L M,NELSON W A,PAAIJMANS K P,et al.The effect of temperature on Anopheles mosquito population dynamics and the potential for malaria transmission[J].PLoS One,2013,8(11):e79276.
[14]MURDOCK C C,BLANFORD S,LUCKHART S,et al.Ambient temperature and dietary supplementation interact to shape mosquito vector competence for malaria[J].J Insect Physiol,2014,67:37-44.
[15]CLAYTON A M,DONG Y M,DIMOPOULOS G.The Anopheles innate immune system in the Defense against malaria infection[J].J Innate Immun,2014,6(2):169-181.
[16]SHOKAL U,ELEFTHERIANOS I.Evolution and function of thioester-containing proteins and the complement system in the innate immune response[J].Front Immunol,2017,8:759.
[17]王英,黄复生.疟原虫在蚊体内发育及蚊抗疟原虫感染的分子机制[J].国际医学寄生虫病杂志,2007,35(4):202-207.
[18]LUNDE T M,BAYOH M N,LINDTJ?RN B.How malaria models relate temperature to malaria transmission[J].Parasit Vectors,2013,6:20.