Collaborative Research:Host and microbial contributions to wax ester lipid digestion in Arctic whales

这个项目将促进对寄主和肠道相关微生物对北极生活的弓头鲸的主要猎物脂肪蜡酯消化的贡献的了解。脂肪的消化和储存是所有食物分子中能量含量最高的，对哺乳动物的生理(即热平衡、生长和繁殖)是必不可少的。尽管这一过程很重要，但人们对海洋动物如何消化蜡酯知之甚少。蜡酯是海洋食物链中一种丰富的脂肪。弓头鲸严重依赖蜡酯消化和脂肪积累，但仍然在寒冷的环境中茁壮成长，比地球上任何其他哺乳动物都活得更长。因此，这项工作将扩展关于弓头鲸、微生物组和消化过程的知识，超越目前在包括人类在内的其他哺乳动物中已知的知识。这项研究将为科学家提供一个框架，以研究由于气候变化而导致的猎物变化如何影响鲸鱼的消化和脂肪增加。该小组将通过新闻稿和在线杂志分享的可公开获取的叙述，广泛地传达项目调查结果。阿拉斯加原住民猎人和他们的家人是这个项目不可或缺的一部分，他们还拥有关于弓头鲸的广泛传统和有记录的知识。为了加强科学家、管理者和利益相关者社区之间的合作关系，该团队将与阿拉斯加州乌恰格维克的捕鲸船长协会及其家人就该项目举行对话。乌恰格维克是美国最北部的城市，拥有土著自给弓头鲸狩猎活动，爱斯基摩人中约有60%是伊尼乌皮亚特人。该项目还将对本科生进行新兴宿主-微生物组研究方法的培训。该项目汇集了脂类组学、微生物生态学、鲸鱼生理学和基因组学方面的专业知识，以解决宿主、胃肠道微生物及其相互作用如何在蜡酯类脂肪消化中发挥作用，这是海洋动物中未被研究的基本代谢过程。研究人员计划围绕两个目标进行实验和分析：1)检查以宿主为基础的蜡酯消化的酶潜力；2)确定肠道相关微生物是否消化蜡酯。这些分析将产生鲸鱼蜡酯消化的概念性模型，基于宿主和微生物的相互作用和过程。具体地说，该团队计划对自给自足捕捞的弓头鲸的胃肠道内多达五个不同部位收集的消化液和肠道内容物进行实验，以检查同位素标记的蜡酯的水解性，以及宿主和微生物群落对消化的贡献。该项目有可能促进和产生关于蜡酯微生物水解的知识，蜡酯是海洋中一种相当重要和丰富的脂肪，目前尚不知道其微生物降解源。研究结果可用于预测气候变化如何影响弓头鲸的摄食生态。研究人员将与阿拉斯加原住民开展公共教育推广活动，交流有关弓头鲸的知识，并将结果提交给阿拉斯加爱斯基摩捕鲸委员会。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will advance understanding about the contribution of host and gut-associated microorganisms to the digestion of wax esters, a major prey lipid, in the Arctic-dwelling bowhead whale. Digestion and storage of lipids, the most energy containing of all food molecules, are essential to the physiology (i.e., heat balance, growth, and reproduction) of mammals. Despite the importance of this process, there is little knowledge about how marine animals digest wax esters, an abundant lipid in the marine food web. The bowhead whale is critically dependent on wax ester digestion and fat accumulation, but nonetheless thrives in a freezing environment and lives longer than any other mammal on Earth. Thus, this work will extend knowledge about bowhead whale, microbiome and digestive processes beyond what is currently known in other mammals, including humans. This research will provide scientists with a framework to investigate how changes in prey, due to changing climate, may impact whale digestion and fat gain. The team will communicate project findings broadly through publicly accessible narratives shared through press releases and an on-line magazine. The Native Alaskan hunters and their families are an integral part of this project and also possess extensive traditional and recorded knowledge about the bowhead whale. To strengthen partnerships between scientists, managers, and stakeholder communities, the team will hold conversations about this project with the Whaling Captain’s Association and their families in Utqiagvik, Alaska, the northernmost U.S. city that hosts Native subsistence bowhead whale hunts, and has a population of approximately 60% Iñupiat Eskimos. This project will also train undergraduates in emerging host-microbiome research methods.This project brings together expertise in lipidomics, microbial ecology, whale physiology and genomics to address how the host, gastrointestinal tract microorganisms, and their interactions play a role in wax ester lipid digestion, a fundamental metabolic process that is understudied in marine animals. The investigators plan to conduct experiments and analyses centered on two aims: 1) to examine the enzymatic potential for host-based digestion of wax esters and 2) to determine if gut-associated microorganisms digest wax esters. These analyses will result in a conceptual model for wax ester digestion in whales, based on host and microbial interactions and processes. Specifically, the team plans to conduct experiments with digestive fluids and intestinal contents collected from up to five different sites within the gastrointestinal tract of subsistence-harvested bowhead whales to examine the hydrolysis of isotope-labeled wax esters, and the contributions of the host and the microbial community to digestion. This project has the potential to advance and produce knowledge on microbial hydrolysis of wax esters, a lipid of considerable importance and abundance in the ocean, for which no microbial degradation sources are yet known. Results may be applied to predicting how climate change may affect bowhead whale feeding ecology. The researchers will engage in public education outreach activities with Native Alaskans to exchange knowledge about bowhead whales and by presenting results to the Alaska Eskimo Whaling Commission.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.