`MO: Exploring the Symbiotic Association Between Tropical Social Insects and Actinomycetes

微生物病原体引起植物和动物的致命疾病，因此是自然选择的重要因素。生物体使用各种方法来保护自己免受病原体的侵害，包括形态结构（例如，植物细胞壁，昆虫的外骨骼），生理过程（例如，免疫系统）和行为。最近对真菌生长的蚂蚁的研究发现了一种以前很少被认识到的宿主防御方法：宿主与放线菌目中产生抗生素的细菌的共生关系。放线菌是革兰氏阳性的丝状细菌，以其产生强效抗生素的能力而闻名。事实上，制药上使用的大多数已知抗生素都来自放线菌。理论预测，群居昆虫特别容易受到寄生虫的攻击，因为它们的种群中有高密度的基因同质个体生活在温暖潮湿的环境中（增加了传播率）。这个微生物观察项目探索了这样一个假设，即社会性昆虫经常与产生抗生素的放线菌共生，以帮助抵御微生物病原体。这一假设将通过结合对两个热带地理位置：波多黎各和哥斯达黎加的群居昆虫的密集实地抽样来检验。该项目的三个具体目标是：i)使用生物脂标记描述与热带群居昆虫相关的广泛微生物群落，ii)通过培养依赖和培养独立方法的结合检测这些微生物群落中的放线菌，以及iii)通过活昆虫菌落和共生微生物的实验工作记录放线菌在宿主防御中的功能作用。该研究将有助于进一步了解放线菌在自然界中的分布和多样性，并描述与热带社会昆虫多样性相关的广泛微生物群落组成。获得的结果将提供关于群居昆虫和产生抗生素的放线菌之间共生关系的起源和维持的见解，并揭示这种类型的宿主防御机制在自然界中是多么普遍。此外，该项目将对热带微生物生态学和共生领域的培训、教育和基础设施产生直接和持久的影响。在美国国家科学基金会国际科学与工程办公室的共同资助下，微生物学和生态学将在国际范围内整合，包括3所不同的大学（威斯康星大学、波多黎各大学和哥斯达黎加大学），并在全球范围内将我们的发现发布在互联网上。每年，数千名K-12学生将在威斯康星州麦迪逊市和哥斯达黎加参加有关微生物和社会性昆虫之间共生关系的展览。在哥斯达黎加产生的更广泛影响包括：按照Daniel Janzen博士创建的外展计划培训当地的副分类学家，以及为改善Área de Conservación瓜纳卡斯特（ACG）的微生物设施作出额外贡献。该MO还将通过在波多黎各大学提供本科和研究生水平的研究经验，直接影响代表性不足的学生。最后，这项研究可能会导致开发新的来源，以发现可能在农业和医学上有应用的新型抗生素。

Microbial pathogens cause virulent diseases in plants and animals, and thus are important agents of natural selection. Organisms use various methods to defend themselves from pathogens, including morphological structures (e.g., plant cell walls, exoskeleton in insects), physiological processes (e.g., immune systems), and behavior. Recent research on fungus-growing ants identified a previously poorly recognized approach to host defense: the symbiotic association of a host with antibiotic-producing bacteria in the order Actinomycetales. Actinomycetes are Gram-positive, filamentous bacteria that are well known for their ability to produce potent antibiotics. Indeed, the majority of known antibiotics used pharmaceutically are derived from actinomycetes. Theory predicts social insects to be especially vulnerable to parasites, given that their colonies harbor a high density of genetically homogenous individuals (increasing transmission rates) living in warm, moist conditions. This microbial observatory project explores the hypothesis that social insects frequently engage in symbiotic associations with antibiotic-producing actinomycetes to help defend against microbial pathogens. This hypothesis will be examined by combining intensive field sampling of social insects from two tropical geographic locations: Puerto Rico and Costa Rica. The three specific goals of this project are to: i) describe the broad microbial community associated with tropical social insects using biolipid markers, ii) detect actinomycetes within these microbial communities through a combination of culture-dependent and culture-independent methods, and iii) document the functional role of actinomycetes in host defense through experimental work with live insect colonies and symbiotic microorganisms. This study will provide greater understanding of the distribution and diversity of actinomycetes in nature as well as describe the broad microbial community composition associated with a diverse collection of tropical social insects. The results obtained will provide insights about the origin and maintenance of symbiotic associations between social insects and antibiotic-producing actinomycetes, as well as reveal how common this type of host defense mechanism is in nature. In addition, this project will have immediate and long lasting impacts in training, education, and infrastructure in the fields of tropical microbial ecology and symbiosis. With co-funding support from the NSF Office of International Science and Engineering, microbiology and ecology will be integrated on an international scale, including 3 different universities (U. of Wisconsin, U. of Puerto Rico and U. of Costa Rica) and worldwide by posting our findings on the internet. Thousands of K-12 students will be exposed each year to exhibits on symbiotic associations between microbes and social insects, both in Madison, WI and in Costa Rica. Broader impacts in Costa Rica include the training of local parataxonomists, following the outreach program created by Dr. Daniel Janzen, and additional contributions towards improvements of microbiology facilities within the Área de Conservación Guanacaste (ACG). This MO will also impact underrepresented students directly by providing undergraduate and graduate level research experiences at U. of Puerto Rico. Finally, this research could lead to the development of new sources for discovering novel antibiotics that may have applications in agriculture and medicine.