Molecular Mechanisms of Dietary Modulation of Intestinal Enzymes in Birds

鸟类肠道酶饮食调节的分子机制

• 批准号: 1354893
• 负责人: William Karasov
• 金额: $ 57.5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1354893&HistoricalAwards=false
• 关键词: Molecular; Mechanisms; Dietary; Modulation; Intestinal

Many birds and mammals are omnivorous, eating a wide variety of foods depending on changing availability or nutritional requirements, and the production of digestive enzymes may increase with availability of substrate in the diet. This mode of regulation maximizes the digestibility of substrates when they are at high dietary levels and minimizes the cost of synthesizing excess enzyme when the substrate is at low levels. Building on past NSF-supported research, the PI will test hypotheses about the molecular regulatory basis of intestinal enzymatic flexibility. Research on digestive enzyme regulation in birds will either strengthen what may be an emerging generality (if in agreement with rodent studies) or transform current thinking about regulation of digestive enzymes. The enhanced understanding will also improve predictions about birds' abilities to respond to changes in diet that occur due to habitat alterations or climate change.Project I focuses on house sparrow (Passer domesticus) juveniles, which do exhibit intestinal carboydrase flexibility, and adults, which do not. The goal is to identify key molecular players and their rates of change in dietary modulation of intestinal carbohydrases and aminopeptidase-N in the juveniles, and test whether the carbohydrase expression regulatory machinery is silenced in the adults switched between diets. Project II focuses on comparison of wild omnivorous representatives from passerine, nonpasserine, and rodent clades. The goal is to test for differences in underlying gene expression regulatory mechanisms and their rates of change. Using tissues harvested from animals fed contrasting diets, the PI will test for molecular mechanisms underlying enzymatic patterns of response and the time-course for regulatory responses. The research supports international collaboration and also training at postdoctoral, graduate, undergraduates and high school levels. Data from these studies will be shared at national and international scientific conferences and through peer-reviewed publications.

许多鸟类和哺乳动物是杂食性的，根据不断变化的可用性或营养需求吃各种各样的食物，并且消化酶的产生可能会随着饮食中底物的可用性而增加。当底物处于高饮食水平时，这种调节模式最大限度地提高了底物的消化率，并且当底物水平较低时，将合成过量酶的成本降至最低。 在过去 NSF 支持的研究的基础上，PI 将测试有关肠道酶灵活性的分子调节基础的假设。对鸟类消化酶调节的研究要么会加强可能正在出现的普遍性（如果与啮齿动物研究一致），要么会改变当前关于消化酶调节的想法。 加深的理解还将提高对鸟类对因栖息地改变或气候变化而发生的饮食变化做出反应的能力的预测。项目I重点关注家麻雀（Passer Domesticus）幼鸟，它们确实表现出肠道碳化酶灵活性，而成鸟则没有。目标是确定幼鱼肠道碳水化合物酶和氨肽酶-N 饮食调节中的关键分子参与者及其变化率，并测试在不同饮食之间切换的成鱼中碳水化合物酶表达调节机制是否被沉默。 项目 II 的重点是对来自雀形目、非雀形目和啮齿动物分支的野生杂食性代表进行比较。 目标是测试潜在基因表达调控机制及其变化率的差异。 PI 将使用从喂食对比饮食的动物身上采集的组织来测试酶促反应模式的分子机制以及调节反应的时间进程。该研究支持国际合作以及博士后、研究生、本科生和高中水平的培训。 这些研究的数据将在国家和国际科学会议上以及通过同行评审的出版物进行共享。