Development and Optimization of a Digital AC-DC Electropenetrograph for Real-Time Recording of On-host Tick Feeding

堪萨斯州立大学（与美国农业部农业研究服务处和哈维马德学院合作）获得了一个奖项，设计、建造和测试一个数字交流-直流电穿透仪，以蜱虫为模型系统，研究吸血节肢动物的实时摄食行为。蜱虫和其他吸血节肢动物传播一系列医学和兽医上重要的病原体，其中许多因气候变化而日益恶化。对蜱虫取食行为进行基础研究的一个重要障碍是，由于蜱虫取食行为被掩盖在宿主皮肤表面之下，因此无法捕捉到观察结果并进行统计分析。蜱虫进食的持续时间长得令人难以置信（成年蜱虫需要7到10天），这进一步加剧了挑战。为了解决这一方法上的缺陷，该项目将开发一种用户和应用友好的数字交流-直流电渗透仪，使研究人员能够以前所未有的细节轻易地调查这些隐藏的行为。该项目汇集了一个跨学科的科学家团队，他们将共同支持12至20名本科生和一名博士后研究员的培训，让他们有机会从工程、计算机科学和生物学的不同角度探索这个新兴的研究兴趣领域。项目本科生和博士后将在项目科学家的指导下组成团队工作。尽可能广泛地招募学员，他们将与来自学术界、政府和工业界的科学家互动，为他们提供探索未来职业道路的机会。学员将参与这项研究的智力和身体方面，并将参与他们设计的迭代评估，使用节肢动物物种组合进行测试：蜱虫（项目模型吸血节肢动物）和蚜虫（电渗透研究的黄金标准昆虫）。项目科学家和学员还将有机会通过社区和科学传播参与平台和活动（如堪萨斯科学博览会）开发和提供相关内容和体验机会，与更广泛的受众分享项目目标。电渗透技术（EPG）是一项革命性的技术，用于研究刺吸植物食性昆虫的掩蔽摄食行为已有近65年的历史。然而，这种实时研究吸血节肢动物的基本行为的方法，包括持续极端时间（几天到几周）的蜱虫，几十年来一直困扰着生物学家。尽管使用现有的模拟交流-直流电渗透仪在蜱虫和蚊子摄食记录方面取得了初步成功，但该仪器在研究脊椎动物宿主上的吸血节肢动物时存在明显的物理局限性。开发一种更加用户友好和应用友好的数字交直流电渗透仪将解决这一挑战，并使突破性的研究能够检测、表征和量化蜱虫和其他吸血节肢动物的渐进和高度协调的摄食行为。然后可以进行假设驱动的研究来研究基本的摄食生物学，并研究宿主因素、媒介特征、病原体和化学干预如何特异性地改变隐藏的节肢动物的摄食行为。在这个项目中，数字交流-直流电渗透仪将在三个科学目标的过程中进行评估：(i)设计和建造一个原型数字交流-直流电渗透仪和相关软件，以记录蜱虫在未注射镇静剂的活体宿主上的摄食；（ii）迭代评估带有活刻度和活主机的原型仪器版本，并根据需要修改原型；（iii）展示数字交流-直流电渗透仪在使用行为阻断化合物时记录和统计比较蜱虫摄食行为的可用性。这项研究的成功完成将提供一种用户友好的、可商业化的仪器和相关软件，这将：1)加速电渗透技术从植物取食昆虫扩展到血液取食节肢动物，2)通过不断发展的数字仪器设计确保这一关键基础设施的持续可用性，3)通过开发相关的机器学习软件实现更快的高通量使用。项目成果将包括开发用户友好的数字交直流电渗透仪和支持“节肢动物物种灵活”软件。这种新颖的研究仪器将为广泛的研究人员提供新的机会，这些研究人员对提高动物和植物农业从血食性和植物食性节肢动物的恢复能力感兴趣。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

An award is made to Kansas State University (in collaboration with USDA Agricultural Research Service and Harvey Mudd College) to design, build, and test a digital AC-DC electropenetrograph to study the real-time feeding behaviors of blood-feeding arthropods, using ticks as the model system. Ticks and other blood-feeding arthropods transmit a wide array of medically- and veterinary-important pathogens, many of these increasingly exacerbated by climate change. An important obstacle to basic research on tick feeding behavior is the inability to capture observations and statistically analyze details of tick feeding behavior because it is masked below the surface of the host’s skin. The challenge is further compounded by the incredibly long durations over which ticks feed (~7 to 10 days for adult ticks). To address this methodological deficit, this project will develop a user- and application-friendly digital AC-DC electropenetrograph which will enable researchers to readily investigate these hidden behaviors in unprecedented detail. This project brings together a transdisciplinary team of scientists that will collectively support the training of 12 to 20 undergraduates and a postdoctoral researcher, giving them opportunities to explore this burgeoning area of research interest from diverse perspectives of engineering, computer science, and biology. Project undergraduates and the postdoctoral researcher will work in teams mentored and guided by project scientists. Trainees, recruited as broadly as possible, will interact with scientists from academia, government, and industry, affording them opportunities to investigate future career paths. Trainees will be involved in both intellectual and physical aspects of this research and will participate in the iterative evaluation of their designs tested using a combination of arthropod species: ticks (project model blood-feeding arthropod) and aphids (gold standard insect for electropenetrography research). Project scientists and trainees will also have opportunity to share project goals with broader audiences through development and delivery of related content and experiential opportunities through community and science communication engagement platforms and events (e.g. Kansas Science Fair).Electropenetrography (EPG) is a transformational technology that has been used for nearly 65 years to study the masked feeding behaviors of piercing-sucking, plant-feeding insects. However, such a means of studying the basic behaviors of blood-feeding arthropods in real time, including ticks that feed for extreme durations (days to weeks), has eluded biologists for decades. Despite initial success with tick and mosquito feeding recordings using the existing analog AC-DC electropenetrograph, this instrumentation presents notable physical limitations for working with blood-feeding arthropods on vertebrate hosts. Developing a more user- and application-friendly digital AC-DC electropenetrograph will solve this challenge and enable ground-breaking investigations to detect, characterize, and quantify the progressive and highly coordinated feeding behaviors performed by ticks and other blood-feeding arthropods. Hypothesis-driven studies can then be performed to study basic feeding biology and investigate how host factors, vector characteristics, pathogens, and chemical interventions specifically modify hidden arthropod blood-feeding behaviors. In this project, the digital AC-DC electropenetrograph will be evaluated over the course of three scientific objectives: (i) Design and build a prototype digital AC-DC electropenetrograph and associated software to record tick feeding on an unsedated live host; (ii) Iteratively evaluate versions of the prototype instrument with live ticks and live host, and modify prototype as needed; and, (iii) Demonstrate the usability of the digital AC-DC electropenetrograph to record and statistically compare tick feeding behaviors upon applications of a behavior-interdicting compound. Successful completion of this research will deliver a user-friendly, commercializable instrument and associated software that will: 1) accelerate expansion of electropenetrography from plant-feeding insects into blood-feeding arthropods, 2) ensure the continued availability of this crucial infrastructure through an evolved digital instrument design, and 3) allow faster high-throughput uses through development-associated machine learning software. Project outcomes will include development of a user-friendly, digital AC-DC electropenetrograph and supporting ‘arthropod species flexible’ software. This novel research instrument will spur new opportunity for a broad community of researchers interested in improving the resiliency of animal and plant agriculture from blood-feeding and plant feeding arthropods.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.