Sivan Arun, Shriram Ananganallur Nagarajan, Muruganandam Nagarajan, Thamizhmani Ramanathan
Regional Medical Research Centre (Indian Council of Medical Research), Post Bag No. 13, Port Blair, Andaman & Nicobar Islands 744 101, India.
Regional Medical Research Centre (Indian Council of Medical Research), Post Bag No. 13, Port Blair, Andaman & Nicobar Islands 744 101, India.
Acta Trop. 2017 Mar;167:121-127. doi: 10.1016/j.actatropica.2016.12.017. Epub 2016 Dec 24.
Climatic changes are responsible, to a certain extent for the occurrence and spread of arboviral pathogens world over. Temperature is one of the important abiotic factors influencing the physiological processes of mosquitoes. Several genes of heat shock protein (HSP) families are known to be expressed in mosquitoes, which aid in overcoming stress induced by elevated temperature. In order to understand expression of HSP family genes in the Andaman population of Aedes aegypti and Aedes albopictus, we used quantitative real-time polymerase chain reaction (qPCR) to examine expression levels of HSPs in response to thermal stress under laboratory and in actual field conditions. HSP genes AeaHsp26, AeaHsp83 and AeaHsc70 were examined by comparing relative transcript expression levels at 31°C, 33°C, 34°C, 37°C and 39°C respectively. Enhanced up-regulation of HSPs was evident in third instar larvae of Ae. aegypti with rise in water temperatures (31°C, 33°C, 34°C) in the containers in the nature and thermally stressed (37°C and 39°C) in laboratory conditions. In Ae. albopictus up-regulation of HSPs was observed in field conditions at 34°C only and when thermally treated at 37°C, while down regulation was evident in larvae subjected to thermal stress in laboratory at 39°C. Data on expression levels revealed that larvae of Ae. aegypti was tolerant to thermal stress, while Ae. albopictus larvae was sensitive to heat shock treatment. Statistical analysis indicated that AeaHsp83 genes were significantly up-regulated in Ae. aegypti larvae after 360min exposure to high temperature (39°C). The difference in expression levels of AeaHsp26, AeaHsc70 and AeaHsp83 genes in Ae. albopictus larvae was statistically significant between different exposure temperatures. All of these genes were significantly up-regulated at 37°C. These results indicate that AeaHsp26, AeaHsc70 and AeaHsp83 are important markers of stress and perhaps function as proteins conferring protection and enhance survival of the Andaman population of both the Aedine species. Biological implications of these findings could impact the vector competencies.
气候变化在一定程度上导致了虫媒病毒病原体在全球的发生和传播。温度是影响蚊子生理过程的重要非生物因素之一。已知热休克蛋白（HSP）家族的几个基因在蚊子中表达，有助于克服高温诱导的应激。为了了解埃及伊蚊和白纹伊蚊安达曼种群中HSP家族基因的表达情况，我们使用定量实时聚合酶链反应（qPCR）来检测在实验室和实际野外条件下热应激反应中HSPs的表达水平。通过比较分别在31°C、33°C、34°C、37°C和39°C时的相对转录本表达水平，检测了HSP基因AeaHsp26、AeaHsp83和AeaHsc70。随着自然环境中容器水温升高（31°C、33°C、34°C）以及实验室热应激条件下（37°C和39°C），埃及伊蚊三龄幼虫中HSPs的上调增强明显。在白纹伊蚊中，仅在野外条件下34°C时以及37°C热处理时观察到HSPs上调，而在实验室39°C热应激的幼虫中下调明显。表达水平数据显示，埃及伊蚊幼虫对热应激有耐受性，而白纹伊蚊幼虫对热休克处理敏感。统计分析表明，在暴露于高温（39°C）360分钟后，埃及伊蚊幼虫中的AeaHsp83基因显著上调。白纹伊蚊幼虫中AeaHsp26、AeaHsc70和AeaHsp83基因在不同暴露温度下的表达水平差异具有统计学意义。所有这些基因在37°C时均显著上调。这些结果表明，AeaHsp26、AeaHsc70和AeaHsp83是应激的重要标志物，可能作为赋予保护作用并提高这两种伊蚊安达曼种群存活率的蛋白质发挥作用。这些发现的生物学意义可能会影响媒介能力。
