Resin to Propolis: Biological origins and role in honey bee social immunity and health

在树脂生产植物和利用它们的各种生物之间，已经进化出了许多迷人的生态相互作用。本研究将探讨蜜蜂如何选择和利用树脂的药理特性，以造福于蜂群的健康。蜜蜂是本地和农业生态系统中最重要的传粉者。自2006年以来，美国每年平均损失超过30%的蜜蜂种群，因此促进蜜蜂的自然防御能力和养蜂业的经济健康是非常重要的。蜜蜂收集树脂并将其沉积在蜂巢中，在那里它被称为蜂胶。巢内壁的蜂胶包膜作为包围蜂群的外部抗菌层，有利于蜜蜂的免疫防御和蜂群水平的社会免疫。本研究将探讨树脂中植物衍生的化学成分是否对蜜蜂的一般微生物和特定病原体提供重要的菌落防御。此外，它将确定蜜蜂是否增加树脂收集和/或在细菌病原体攻击后将树脂的植物来源转换为具有更大生物活性的树脂。将追求四个目标：1)确定蜂胶包膜是否对细菌病原体，类芽孢杆菌幼虫有活性，类芽孢杆菌是田间菌落中美国腐殖病的病原体。研究结果将揭示促进蜜蜂健康的新方法，并解释自然收集的化合物在减轻蜜蜂疾病中的作用。2)量化蜜蜂是否增加树脂收集以应对细菌病原体的挑战。这些研究将揭示群体中相对罕见的蜜蜂收集树脂的行为机制，这些蜜蜂的觅食选择有助于群体层面的社会免疫。3)通过代谢物指纹图谱分析鉴定蜂胶配方中所用树脂的植物来源。这些分析的发现将建立生物活性物质的来源与其对蜜蜂健康的最终影响之间的联系。这一联系将为未来研究全球蜜蜂亚种中树脂使用与健康之间的关系提供见解。4)利用生物测定驱动的纯化和基于代谢组学的方法鉴定蜂胶中抑制蜜蜂细菌病原体生长的生物活性成分。现代生物检测引导的化学分离将有助于发现以前未知的抗菌物质，并为树脂在植物-动物相互作用的生态学和进化中的药理作用开辟新的研究途径。这项研究将吸引和教育从应用养蜂到代谢组学分析和分子遗传学等学科的学生。通过与威斯康辛大学河瀑布分校的生物学教授合作，参加BEE课程（蜜蜂强化教育）的本科生将分析蜂浆处理过的蜂群中蜜蜂的病毒水平，这将帮助他们将微生物学，生态学，植物学和分子生物学概念与相关的“现实世界”传粉者减少问题联系起来。PI的研究、教学和推广工作相结合，确保这项研究将被翻译并传播给不同的受众，包括科学家、传统和非传统学生、养蜂人和公众。

A number of fascinating ecological interactions have evolved between resin producing plants and the wide array of organisms that exploit them. This research will explore how honey bees, Apis mellifera, select and exploit the pharmacological properties of resin to benefit the health of the colony. Honey bees are the most important pollinators of native and agro-ecosystems. Due to the average annual loss of over 30% of the U.S. honey bee colonies since 2006, it is important to promote the natural defenses of honey bees and the economic health of the beekeeping industry. Honey bees collect resin and deposit it in the nest where it is called propolis. A propolis envelope lining the inner walls of the nest acts as an external antimicrobial layer surrounding the colony, benefiting bee immune defenses and colony-level social immunity. This research will explore if plant-derived chemical components in resin provide an important colony defense against both general microorganisms and specific pathogens of honey bees. Further it will determine if bees increase resin collection and/or switch botanical sources of resin to those with greater biological activity after challenge with a bacterial pathogen. Four objectives will be pursued: 1) Determine if the propolis envelope is active against the bacterial pathogen, Paenibacillus larvae, the causative agent of American foulbrood disease in field colonies. Findings will reveal novel approaches to promote honey bee health and explain the function of naturally collected compounds in mitigating diseases of honey bees. 2) Quantify if honey bees increase resin collection in response to challenge with a bacterial pathogen. These studies will shed light on the behavioral mechanisms underlying the collection of resin by a relatively rare subset of bees in the colony whose foraging choices contribute to social immunity at the colony level. 3) Identify the botanical sources of resins used by honey bees for propolis formulation by metabolite fingerprinting analysis. Findings from these analyses will establish the link between the origin of the biologically active substances and their ultimate impacts on honey bee health. This link will provide insight for future studies into the relationship between resin use and health among honey bee subspecies across the globe. 4) Identify bioactive components of propolis that inhibit growth of a honey bee bacterial pathogen using both bioassay-driven purification and metabolomics-based methods. Modern bioassay-guided chemical isolation will facilitate the discovery of previously unknown antimicrobial substances and open new research avenues into the role of resins as pharmacological agents in the ecology and evolution of plant-animal interactions. This research will attract and educate students in disciplines from applied beekeeping to metabolomic analyses and molecular genetics. Through a collaboration with Biology professors at the University of Wisconsin, River Falls, undergraduates participating in the BEE course (Bees Enhancing Education) the will analyze virus levels in bees from propolis-treated colonies, which will help them connect microbiology, ecology, botany, and molecular biology concepts to the relevant, "real-world" problem of pollinator decline. The PI's combined research, teaching, and extension appointments ensure that this research will be translated and disseminated to a diverse audience including scientists, traditional and non-traditional students, beekeepers, and the general public.