Predicting Chemical Transformations of Extracellular Biochemicals: The Role of Iron and Manganese (Hydr)Oxides

预测细胞外生化物质的化学转化：铁和锰（氢）氧化物的作用

• 批准号: 0719787
• 负责人: Alan Stone
• 金额: $ 20万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0719787&HistoricalAwards=false
• 关键词: Predicting; Chemical; Transformations; Extracellular; Biochemicals

Biochemicals produced by organisms perform a diverse array of functions in the surrounding environment. Concentrations are decreased through biodegradation, the action of extracellular enzymes, and chemical reactions with dissolved and particulate-bound geochemicals.Hypotheses: (1) Iron and manganese (hydr)oxides, prevalent in soils and sediments, are major sinks for excreted biochemicals. (2) Pathways and rates of these chemical reactions can be predicted based on knowledge of the identity, number, and arrangement of reactive functional groups within the biochemical structure.Objective: develop an understanding of relationships between biochemical structure and chemical reactivity that can serve as the basis for predicting pathways and rates of reaction. To illustrate our approach, consider the antibiotics penicillic acid, produced by fungi, and patulin, produced by mold. For these chemicals to persist long enough in soils to kill pathogenic or competitor bacteria, they must be resistant to oxidation by iron and manganese (hydr)oxides. In addition to studying the two biochemicals directly, we will also examine substructures Y1 and Y2 to learn more about how the arrangement of functional groups affect pathways and rates of oxidation by iron and manganese (hydr)oxides. Quorum-sensing (QS) signal compounds and QS inhibitor compounds are important aspects of this work. Oxidation and hydrolysis reactions involving Fe(OH)3(ferrihydrite) and FeOOH(goethite) will be emphasized.Intellectual Merit: The proposed work serves as a bridge between geochemistry, physical organic chemistry, and microbiology/ecology. It facilitates a new activity: predicting pathways and rates of chemical transformation for newly-discovered biochemicals as a function of their structure/functional groups and prevalent geochemical conditions. Greater appreciation for the geochemical context for particular extracellular biochemicals, in turn, will encourage molecular biologists to seek novel natural products and regulatory mechanisms.Broader Impacts: The nature of the proposed work entices students to cross traditional disciplinary boundaries, and engages them in new lines of inquiry. Undergraduates have changed their professional trajectories while in the PI's laboratory, e.g. from Chemical Engineering to Plant Science, from Chemistry to Environmental Engineering, from Geography to Environmental Chemistry. Nine of the PI's thirteen PhD graduates are women. One is now performing postdoctoral work in Molecular Biology. For this project, we seek recruits from underrepresented backgrounds that have these professional trajectories in mind.One goal for the proposed work is to write tutorials at different levels, one for high school students and the general public, one for undergraduates, one for graduate students and researchers. In this way, individuals will have access to information that had not been available to them previously, and will be inspired to branch out and explore new fields.

生物体产生的生物化学物质在周围环境中发挥着各种各样的功能。 通过生物降解、细胞外酶的作用以及与溶解的和颗粒结合的地球化学物质的化学反应，浓度降低。 (2)这些化学反应的途径和速率可以预测的基础上的身份，数量和反应性官能团的生化结构内的安排的知识。目标：发展的生化结构和化学反应性之间的关系，可以作为预测的基础上的途径和反应速率的理解。 为了说明我们的方法，考虑由真菌产生的抗生素青霉素酸和由霉菌产生的展青霉素。 为了使这些化学物质在土壤中持续足够长的时间以杀死致病菌或竞争细菌，它们必须能抵抗铁和锰（氢）氧化物的氧化。 除了直接研究这两种生化物质外，我们还将研究亚结构Y1和Y2，以了解更多关于官能团的排列如何影响铁和锰（氢）氧化物氧化的途径和速率。 群体感应（QS）信号化合物和QS抑制剂化合物是这项工作的重要方面。 涉及Fe（OH）3（水铁矿）和FeOOH（针铁矿）的氧化和水解反应将被强调。智力优点：拟议的工作作为地球化学，物理有机化学和微生物学/生态学之间的桥梁。 它促进了一项新的活动：预测新发现的生物化学物质的化学转化途径和速率，作为其结构/官能团和普遍的地球化学条件的函数。 对特定细胞外生物化学物质的地球化学背景的更高评价，反过来，将鼓励分子生物学家寻求新的天然产物和调控机制。更广泛的影响：拟议工作的性质诱使学生跨越传统的学科界限，并从事新的调查路线。 在PI的实验室里，本科生改变了他们的专业轨迹，例如从化学工程到植物科学，从化学到环境工程，从地理到环境化学。 PI的13名博士毕业生中有9名是女性。 其中一人现在从事分子生物学博士后工作。 在这个项目中，我们寻找那些具有这些职业轨迹的低代表性背景的人。拟议工作的一个目标是编写不同层次的教程，一个针对高中生和普通公众，一个针对本科生，一个针对研究生和研究人员。 通过这种方式，个人将能够获得他们以前无法获得的信息，并将受到启发，进行分支和探索新的领域。