EAGER: Exploratory Studies of Metabolic Water in Plants and Microorganisms

在呼吸过程中，水在生物体的细胞中产生。这个项目试图了解这种水对植物和土壤微生物的重要性。当外部供水不足时，这种新陈代谢水可能是至关重要的。该项目将检验代谢水对植物抵御干旱和修复干旱对植物水分运输系统造成的损害的重要性这一想法。该项目还将测试代谢水为土壤微生物提供在干燥土壤中维持活动的手段的想法。该项目将采用新的技术，通过一种化学上不同形式的氧来提供代谢水的示踪剂，这种氧可以区分代谢水和非新陈代谢产生的水。这项研究中开发的监测复杂活组织新陈代谢的技术，在研究人类疾病和癌症检测的线粒体疾病方面具有潜在的应用。本科生将积极参与这项研究，接受微生物和植物生态学以及呼吸代谢方面的培训。在动物、植物和好氧微生物的呼吸代谢过程中，会产生代谢水。尽管代谢水在某些动物中的重要性已得到充分认识，但对代谢水在微生物和植物中的生理或生态意义几乎一无所知。该项目假设，新陈代谢水对土壤微生物的水平衡有重要贡献，通过提供减缓干燥和推迟休眠开始的内部水源，延长干燥土壤中的活动时间。对于植物来说，假设代谢水通过在正压下提供局部水源来帮助栓塞的血管细胞恢复水的运输功能，从而有助于栓塞细胞的重新填充。为了验证这些假设，该项目使用了一套创新的观察、实验和建模活动。一种关键的实验方法是在空气中孵化富含氧稳定同位素18-O的氧气气体，产生富含18-O的代谢水，这种水可以通过其独特的同位素组成与环境水区分开来。18-O研究还采用了两种尖端成像技术：高分辨率X射线计算机断层扫描，以显示栓塞血管的再充盈情况，以及稳定同位素拉曼光谱，以定位细胞和组织中标记的18-O代谢水。来自这些研究的新见解将在理解植物和微生物的中央能量代谢和水分关系的相互作用方面具有变革性。

Water is produced in the cells of organisms during respiration. This project seeks to understand the importance of this water for plants and soil microorganisms. This metabolic water is potentially of vital importance when external water supply is low. The project will test the idea that metabolic water is important to plants in withstanding drought and repairing drought-induced damage to the plant water transport system. The project will also test the idea that metabolic water provides a means for soil microbes to sustain activity in dry soils. The project will employ novel techniques based on providing a tracer for metabolic water via a chemically distinct form of oxygen that allows distinguishing metabolic water from water that is not produced by metabolism. The techniques developed in this study to monitor metabolism in complex living tissues have potential applications for studying mitochondrial disorders underlying human disease and cancer detection. Undergraduate students will be active participants in the research, receiving training in microbial and plant ecology, and respiratory metabolism. Metabolic water is produced during respiratory metabolism in animals, plants, and aerobic microorganisms. Although its vital importance is well recognized in some animals, virtually nothing is known about the physiological or ecological significance of metabolic water in microorganisms and plants. The project hypothesizes that metabolic water contributes importantly to the water balance of soil microorganisms, prolonging activity in drying soils by providing an internal source of water that slows desiccation and delays the onset of dormancy. For plants, it's hypothesized that metabolic water contributes to the recovery of water transport function in embolized vascular cells by providing a local source of water under positive pressure that contributes to refilling of embolized cells. To test these hypotheses, the project uses a suite of innovative observations, experiments, and modeling activities. A key experimental methodology involves incubations in air containing oxygen gas enriched in the stable isotope of oxygen, 18-O, resulting in 18-O enriched metabolic water that can be distinguished from environmental water by its distinctive isotopic composition. The 18-O studies are augmented with two cutting-edge imaging techniques: high-resolution x-ray computed tomography to visualize refilling of embolized vessels, and stable isotope Raman spectroscopy to locate 18-O labeled metabolic water within cells and tissues. New insights from these studies will be transformational in terms of understanding the interaction of central energy metabolism and water relations in plants and microorganisms.