MSB - Investigating the Relationship Between Structural Diversity and Functional Resilience to Stress in Ammonia-Oxidizers

“该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。“这个项目将评估允许氨氧化细菌对压力做出反应的基本因素。一个生态框架的基础上在社区层面的差异基因表达将与确定性的数学模型，以准确地表征化学应激氨氧化细菌的功能，如果发现是相关的，氨氧化古菌。操作假设是氨氧化剂对压力的弹性是压力系统中微生物系统发育多样性的函数，并且这种弹性是由于菌株之间以生长为代价对压力抗性的能量投资的差异而产生的。该项目采用全细胞生理指标和微生物生态学方法，跟踪重金属镉和铜干扰下氨氧化菌的群落多样性、物种优势度、种群水平活性和差异基因表达的变化。将维持含有细菌群落的制药厂规模的反应器，并将其暴露于铜和镉，并分析生物反应器中微生物的行为。该项目将对硝化作用经常受到化学压力的系统产生更广泛的影响，包括用氯胺消毒的饮用水管道和水产养殖处理系统，其中氨的去除是优化鱼类生产的关键。随着世界范围内许多河口水质的恶化，越来越多的生物处理系统正在实施脱氮。脱氮工艺的关键是氨氧化。实验工作的结果将允许用于设计废水处理系统的当前计算机模型得到扩展和改进，从而激励设计更强大的脱氮处理系统。最后，该计划的参与者将把各种项目活动整合到现有的外展计划中，为小学生开发环境微生物学和工程学习模块，帮助他们了解微生物如何伤害和帮助人类。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." This project will evaluate the basic factors that allow ammonia oxidizing bacteria to respond to stress. An ecological framework based in differential gene expression at the community level will be integrated with deterministic mathematical models to accurately characterize the function of chemically stressed ammonia oxidizing bacteria and, if found to be relevant, ammonia oxidizing archaea. The operating hypothesis is that the resilience of ammonia oxidizers to stress is a function of microbial phylogenetic diversity in the stressed system and this resilience arises due to differences among strains in their investment of energy towards stress resistance at the expense of growth. The project uses whole cell physiological indicators and microbial ecology methods to follow the changes in the community diversity, species dominance, population-level activity, and differential gene expression of ammonia oxidizers perturbed with the heavy metals cadmium and copper. Laboratory-scale reactors containing bacterial communities will be maintained and exposed to copper and cadmium, and the behavior of the microorganisms in the bioreactors will be analyzed. This project will have broader impacts for systems where nitrification is often chemically stressed, including drinking water pipes that are disinfected with chloramines and aquaculture treatment systems where ammonia removal is key to optimum fish production. An increasing number of biotreatment systems are implementing nitrogen removal, as the water quality in many estuaries is deteriorating worldwide. Key to the nitrogen removal process is ammonia oxidation. Results from the experimental work will allow current computer models that are used to design wastewater treatment systems to be expanded and improved, thereby motivating the design of more robust nitrogen removal treatment systems. Finally, the participants in this program will integrate various project activities into an existing outreach program that develops environmental microbiology and engineering learning modules for grade school children to help them understand how microorganisms both harm and help humans.