Homeostasis of Prokaryotes in Natural Environments

自然环境中原核生物的稳态

• 批准号: 1257571
• 负责人: James Cotner
• 金额: $ 52.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1257571&HistoricalAwards=false
• 关键词: Homeostasis; Prokaryotes; Natural; Environments

Phosphorus is one of the most abundant elements in living organisms but it is not very abundant on the Earth's surface. Scientists and medical practitioners have a general idea of how much is required by living things, but they do not really know how much phosphorus is too little and how much is too much. How do organisms, communities and ecosystems fundamentally change when there is too much or too little of this essential element present? This is an important issue because for the past century, humans have fertilized both terrestrial and aquatic ecosystems with excessive quantities of phosphorus as well as nitrogen. On the other hand, how do organisms deal with a lack of phosphorus in the environment? Are organisms able to substitute arsenic, an element that is typically thought to be toxic, for phosphorus? The answers to these questions have important implications for understanding how life originated and evolved on the early Earth in a relatively phosphorus-poor world. The goal of the proposed study is to understand how organisms regulate their biomass phosphorus composition in environments where phosphorus availability is extremely high, extremely low and/or extremely variable. How important is it to be able to store excess phosphorus and how important is it to be able to 'make do' with less? These questions will be examined by studying bacteria isolated from lakes in the agriculturally impacted upper Midwest. The central hypothesis is that phosphorus-rich environments select for bacteria that grow fast and are not able to vary the amount of phosphorus they require whereas phosphorus-poor environments select for bacteria that grow slowly and can vary the amount of phosphorus they require. The ability of both of these kinds of bacteria will also be examined to see if they can substitute arsenic for phosphorus. What happens when both of these 'flavors' of bacteria are present in the environment and what are the implications of this for other organisms in their community and in ecosystems?Broader impacts: This work will train undergraduates, a graduate student and a post-doctoral fellow. A graduate student and post-doctoral fellow will work with the PI both on the research-focused aspects of this project as well as a transformational program that was developed at the Mayo Clinic in Rochester, MN called InSciedOut. In the InSciedOut program, scientists work directly with elementary school teachers and students on a project-based science curriculum. Also, the bacterial isolates from this project will be used in a new course on Practical Genomics at the University of Minnesota. Outreach activities will be focused on a set of lectures focused on microbes and the oceans for the Minnesota International Center's Great Decisions Lecture Series.

磷是生物体中最丰富的元素之一，但地球表面的含量并不丰富。科学家和医生对于生物需要多少磷有一个大致的了解，但他们并不真正知道多少磷是太少，多少是过多。当这种基本元素过多或过少时，生物体、群落和生态系统会如何从根本上发生变化？这是一个重要问题，因为在过去的一个世纪里，人类向陆地和水生生态系统施肥了过量的磷和氮。另一方面，生物体如何应对环境中磷的缺乏？生物体能否用砷（一种通常被认为有毒的元素）代替磷？这些问题的答案对于理解生命如何在早期地球上相对贫磷的世界中起源和进化具有重要意义。拟议研究的目的是了解生物体如何在磷利用率极高、极低和/或变化极大的环境中调节其生物量磷组成。能够储存过量的磷有多重要，以及能够用更少的磷来“凑合”有多重要？这些问题将通过研究从受农业影响的中西部北部湖泊中分离出来的细菌来检验。中心假设是，富磷环境选择生长快速且无法改变其所需磷量的细菌，而贫磷环境选择生长缓慢且可以改变其所需磷量的细菌。还将检查这两种细菌的​​能力，看看它们是否可以用砷代替磷。当环境中存在这两种细菌“味道”时会发生什么？这对其群落和生态系统中的其他生物体有何影响？更广泛的影响：这项工作将培训本科生、研究生和博士后。一名研究生和博士后研究员将与 PI 合作，致力于该项目的研究重点以及由明尼苏达州罗切斯特市梅奥诊所开发的名为 InSciedOut 的转型项目。在 InSciedOut 项目中，科学家直接与小学教师和学生一起研究基于项目的科学课程。此外，该项目的细菌分离物将用于明尼苏达大学实用基因组学的新课程。外展活动将集中于明尼苏达国际中心重大决策讲座系列的一系列以微生物和海洋为主题的讲座。