The advantages and challenges of a glucose and fructose-rich diet

富含葡萄糖和果糖饮食的优点和挑战

• 批准号: RGPIN-2020-06344
• 负责人: Welch, Kenneth
• 金额: $ 4.01万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717756
• 关键词: advantages; challenges; glucose; fructose; rich

My lab seeks to understand the diversity of animal form and function through the lens of energetics and metabolic biochemistry. My general research program focuses on birds (typically hummingbirds) and new world bats because these animals are among the smallest endotherms, are volant, and thus face exceptional challenges to maintaining metabolic homeostasis, while containing species with a rich diversity of dietary ecologies. The makeup of a nectarivore (and to a lesser extent, frugivorous) diet is deceptively simple, composed almost exclusively of glucose, fructose, and the disaccharide sucrose. However, this simplistic diet imposes incredible challenges to energy homeostasis. Pathways for the absorption, transport, and direct oxidation of dietary carbohydrate in most vertebrates are extremely limited. Further, a high sugar diet is invariably pathogenic in most animals. However, work from my group has shown how dietary sugar uptake and oxidation pathways, the so-called “sugar oxidation cascade” are enhanced in these animals to facilitate high rates of both immediate oxidation, and conversion of sugars to fat to fuel future needs. In particular, hummingbirds and nectar bats show remarkable abilities to use not just glucose, but also fructose; an ability absent in other groups. Still, little is known about how these animals orchestrate or prioritize the use of glucose and fructose components in their diet while simultaneously dealing with associated oxidative and glycation stress. Within bats, this question is particularly interesting because frugivory and nectarivory have evolved independently in several lineages, and preliminary data from my lab shows that they may use component sugars in distinct ways. My group will use and integrative suite of approaches to explore, 1) the relative use of glucose and fructose to fuel immediate and future energy needs in relation to dietary ecology in neotropical bats and 2) the role of carbohydrate transporters in the differential use and regulation of flux of these sugars. Additionally, I will 3) examine whether the potential endogenous capacities for building antioxidant defense or the ability to tolerate or avoid the deleterious consequences of glycation stress are correlated with evolution of nectarivory or frugivory in bats. Results from this proposed work will reveal the ways in which diet and metabolic physiology co-evolve among neotropical bats. Our findings will help both physiologists and ecologists to contextualize interspecific variation in foraging and locomotor behaviour as well as energetics, and will inform predictions regarding how environmental challenges may differentially affect bat survival and performance via bats' abilities to match fuel and energy intake to demand.

我的实验室试图通过能量学和代谢生物化学的透镜来理解动物形态和功能的多样性。我的一般研究项目主要集中在鸟类（通常是蜂鸟）和新大陆蝙蝠，因为这些动物是最小的恒温动物之一，是volant，因此面临着特殊的挑战，以维持代谢稳态，同时包含具有丰富多样性的饮食生态物种。 食蜜动物（在较小程度上也是食果动物）的饮食结构看似简单，几乎完全由葡萄糖、果糖和双糖蔗糖组成。然而，这种简单的饮食对能量平衡提出了难以置信的挑战。在大多数脊椎动物中，膳食碳水化合物的吸收、运输和直接氧化途径极其有限。此外，高糖饮食在大多数动物中总是致病的。然而，我的小组的工作已经表明，饮食中的糖摄取和氧化途径，即所谓的“糖氧化级联”，在这些动物中是如何增强的，以促进高速率的立即氧化和糖转化为脂肪，以满足未来的需求。特别是蜂鸟和花蜜蝙蝠表现出非凡的能力，不仅使用葡萄糖，而且还使用果糖;其他群体缺乏这种能力。尽管如此，人们对这些动物如何在饮食中协调或优先使用葡萄糖和果糖成分，同时处理相关的氧化和糖化应激知之甚少。在蝙蝠中，这个问题特别有趣，因为食果性和食蜜性在几个谱系中独立进化，我实验室的初步数据显示，它们可能以不同的方式使用糖。 我的小组将使用一套综合的方法来探索，1）葡萄糖和果糖的相对使用，以满足新热带蝙蝠饮食生态学中当前和未来的能量需求，2）碳水化合物转运蛋白在这些糖的差异使用和流量调节中的作用。此外，我将研究是否潜在的内源性抗氧化防御能力或耐受或避免糖化应激的有害后果的能力与蝙蝠的食蜜性或食果性进化相关。 这项工作的结果将揭示新热带蝙蝠的饮食和代谢生理学共同进化的方式。我们的研究结果将有助于生理学家和生态学家将觅食和运动行为以及能量学的种间变化置于情境中，并将告知有关环境挑战如何通过蝙蝠将燃料和能量摄入与需求相匹配的能力来差异化地影响蝙蝠生存和表现的预测。