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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740734
• 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和代谢生物化学的角度来理解动物形式和功能的多样性。我的一般研究计划的重点是鸟类（通常是蜂鸟）和新世界蝙蝠，因为这些动物是最小的吸热者之一，是志愿者，因此面临着保持代谢稳态的非凡挑战，同时含有饮食生态多样性的物种。花蜜（较小程度上奶油）饮食的构成是看似简单的，几乎由葡萄糖，果糖和二糖蔗糖组成。但是，这种简单的饮食对能量稳态构成了令人难以置信的挑战。大多数脊椎动物中饮食碳水化合物吸收，运输和直接氧化的途径极为有限。此外，在大多数动物中，高糖饮食总是具有致病性。但是，我小组的工作表明，这些动物的饮食糖摄取和氧化途径，所谓的“糖氧化级联”如何增强，以促进高即时氧化的高速率，以及将糖转化为脂肪以促进未来需求。特别是，蜂鸟和花蜜蝙蝠不仅可以使用葡萄糖，而且还具有果糖。其他群体缺乏的能力。尽管如此，对于这些动物如何在饮食中使用葡萄糖和果糖成分的使用，同时处理相关的氧化和糖化胁迫，但知之甚少。在蝙蝠中，这个问题特别有趣，因为节俭和花蜜在几个谱系中独立发展，而我实验室的初步数据表明，它们可能以不同的方式使用零件糖。我的小组将使用探索方法和整合套件来探索，1）葡萄糖和果糖的相对使用在新热带蝙蝠的饮食生态学上促进了即时和未来的能量需求，以及2）碳水化合物转运蛋白在这些糖的氧化和调节中的作用。此外，我将3）检查建立抗氧化剂防御的潜在内源能力，还是耐受或避免糖化应力的有害后果的能力是否与蝙蝠中的蜜饯或淡化的能力相关。这项拟议的工作的结果将揭示新热带蝙蝠之间饮食和代谢生理共同进化的方式。我们的发现将有助于生理学家和生态学家在觅食和运动行为以及能量学方面的种间变化以及能量学的情况下，并将告知有关环境挑战如何通过蝙蝠匹配燃料和能量需求的能力来差异地影响BAT的生存和性能的预测。