Midgut Bacteria in Aedes aegypti and Vector Competence

描述(申请人提供)：登革热是世界上最重要的节肢动物传播的病毒疾病。没有有效的疫苗可用，蚊子控制仍然是唯一的预防选择。登革热病毒向人类宿主的传播完全取决于是否有合格的蚊子媒介，通常是埃及伊蚊。众所周知，昆虫肠道中的微生物在昆虫生物学中起着非常重要的作用，并能影响一些昆虫病原体的生长。将转基因技术应用于节肢动物传播的疾病控制方面正在做出相当大的努力，重点是种群替换。一个主要的焦点是使用这些技术来产生携带破坏其传播病原体能力的基因的蚊子。另一种可能性是副转基因，即能够在蚊子中肠定居的细菌将被用来携带和表达抗病原体效应基因，从而防止蚊子将疾病传播给人类。Ae.中肠正常菌群的研究现状。埃及伊蚊，对健康的潜在影响是有限的。该项目的长期目标是加深对Ae之间相互关系的理解。埃及伊蚊种群及其天然中肠细菌区系。这项研究将主要在印度浦那大学与Yogesh Shouche博士合作完成，作为NIH第二号补助金的延伸。RO1-AI059342。这个项目的具体目的是：调查中肠细菌对Ae健身的作用。埃及伊蚊。这包括以下努力：1)比较成虫的中肠细菌区系。埃及伊蚊在实验室菌株和野外分离株中，2)检查中肠细菌对Ae的影响。埃及伊蚊生活史特征，以及3)中肠细菌对登革热病毒易感性的影响。埃及伊蚊。细菌鉴定将通过从可培养细菌和中肠总内容物(包括不可培养物种)中扩增和测序12S和16S rRNA基因来确定。中肠细菌对健康的影响将在接受抗生素治疗的成年人中进行检查，以确定几个生活史特征，包括发育时间、成人身体大小、血粉大小、繁殖力、生育力和成年寿命。女性登革热耐药株和易感株对登革热病毒易感性的研究埃及伊蚊的菌落将在正常和抗生素治疗的个体中进行比较。与公共卫生相关：登革热对25亿人构成威胁，估计每年有5000万登革热病例和约2.4万人死于更严重的出血性形式。没有疫苗可用，疾病预防依赖于控制蚊子媒介，主要是埃及伊蚊。这项拟议的研究将提供有关中肠细菌对蚊子生物学的影响的有价值的新信息，包括支持登革热病毒并将其传播给人类的能力。

DESCRIPTION (provided by applicant): Dengue is the most important arthropod-borne viral disease in the world. No effective vaccines are available and mosquito control remains the only prevention option. Transmission of dengue virus to a human host is totally dependent upon availability of a competent mosquito vector, usually Aedes aegypti. It is well known that microbes in the insect gut play a very important role in the biology of insects, and can influence growth of some insect pathogens. Considerable effort is being directed toward applying transgenesis technology to arthropod-borne disease control, with an emphasis on population replacement. A major focus is to use these techniques to generate mosquitoes that carry genes that disrupt their ability to transmit pathogens. Another possibility is paratransgenesis, wherein bacteria capable of colonizing the mosquito midgut would be used to carry and express anti-pathogen effector genes and thereby prevent disease transmission to humans by the mosquito. The present knowledge on normal midgut bacterial flora in Ae. aegypti and the potential effects on fitness is limited. The long-term objectives of this project are to develop an understanding of the interrelationships between Ae. aegypti populations and their natural midgut bacterial flora. This research will be done primarily in India at Pune University in collaboration with Dr. Yogesh Shouche, as an extention of NIH Grant No. RO1-AI059342. The specific aim of this project is to: Investigate the role of midgut bacteria on fitness in Ae. aegypti. This includes efforts to: 1) compare midgut bacterial flora of adult Ae. aegypti in laboratory strains and field isolates, 2) examine the impact of midgut bacteria on Ae. aegypti life history traits, and 3) determine the effect of midgut bacteria on dengue virus susceptibility in Ae. aegypti. Bacterial identity will be determined by amplification and sequencing of the 12S and 16S rRNA genes from both culturable bacteria and total midgut contents, which will include unculturable species. The impact of midgut bacteria on fitness will be examined among antibiotic treated adults for several life history traits including development time, adult body size, bloodmeal size, fecundity, fertility, and adult longevity. Dengue virus susceptibility of females from dengue refractory and susceptible Ae. aegypti colonies will be compared among normal and antibiotic treated individuals. PUBLIC HEALTH RELEVANCE: Dengue is a threat to >2.5 billion people, with estimates of 50 million cases of dengue fever and ~24,000 deaths due to the more severe hemorrhagic form each year. No vaccines are available and disease prevention is dependent on controlling the mosquito vector, primarily Aedes aegypti. The proposed research will provide valuable new information regarding the influence of midgut bacteria on the biology of the mosquito, including the ability to support and transmit the dengue virus to humans.