EAGER: Alternative defensive mechanisms of autotrophs from harmful reactive oxygen species

EAGER：自养生物免受有害活性氧的替代防御机制

• 批准号: 1664052
• 负责人: Hidetoshi Urakawa
• 金额: $ 5.4万
• 依托单位: Florida Gulf Coast University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1664052&HistoricalAwards=false
• 关键词: EAGER; Alternative; defensive; mechanisms; autotrophs

Cyanobacteria (also known as blue-green algae) are capable of thriving in a variety of environments. Ecological disturbances often favor growth of cyanobacteria because of their capability to adapt to rapid changes in the environment. Sometimes changes in environmental conditions can result in dense populations of cyanobacteria, (algal bloom) and they may also produce high concentrations of toxins (cyanotoxins) that kill fish and are a hazard to humans. The goal of this EArly-concept Grant for Exploratory Research (EAGER) project is to test whether cyanotoxins have an important alternative biochemical and ecological function, namely, to protect the cyanobacteria by removing hydrogen peroxide. If this proves to be true, it would transform our understanding of the structure and function of freshwater lakes. The results from this EAGER project may also lead to more effective and economical management of harmful cyanobacerial blooms. Cyanotoxins released during harmful algal blooms can pose health risks, and require millions of dollars to decontaminate freshwater supplies. The project will also include research training opportunities for undergraduate and graduate students, with efforts to broaden participation in science.One of the most important environmental gradients is formed by oxygen, and its availability is fundamental to the distribution patterns of life. Cyanobacteria were the first lineage to establish oxygen-producing photosynthesis. Cyanobacterial photosynthesis captures solar energy, but it comes at the risk of producing reactive oxygen species such as hydrogen peroxide. The development of a cellular process capable of handling intracellular reactive oxygen molecules was key to the evolution of cyanobacterial photosynthesis. This EAGER project will test an intriguing hypothesis about why cyanobacteria produce cyanotoxins, that they function to sequester hydrogen peroxide, or otherwise convert it to a non-reactive form. In this project, toxic and non-toxic cyanobacterial strains will be compared with respect to hydrogen peroxide production. A new hydrogen peroxide microsensor will be used to examine the microscale distribution of hydrogen peroxide in thin surface lake water to determine whether (consistent with the hypothesis) it is inversely proportional with the abundance of toxin-producing cyanobacteria. Finally, studies will determine whether the ability to isolate and grow novel cyanobacteria in culture can be improved by adding alpha-keto acids to scavenge any hydrogen peroxide produced by cells.

蓝藻（也称为蓝绿藻）能够在各种环境中繁衍生息。生态干扰通常有利于蓝藻的生长，因为它们能够适应环境的快速变化。有时，环境条件的变化会导致蓝藻密集繁殖（藻华），它们还可能产生高浓度的毒素（蓝藻毒素），从而杀死鱼类并对人类造成危害。这个早期概念探索性研究资助（EAGER）项目的目标是测试蓝藻毒素是否具有重要的替代生化和生态功能，即通过去除过氧化氢来保护蓝藻。如果这被证明是正确的，它将改变我们对淡水湖的结构和功能的理解。 该 EAGER 项目的结果还可能导致对有害蓝藻水华进行更有效和更经济的管理。有害藻华期间释放的蓝藻毒素可能会造成健康风险，并且需要数百万美元来净化淡水供应。该项目还将包括为本科生和研究生提供研究培训机会，努力扩大科学参与。最重要的环境梯度之一是由氧气形成的，其可用性对于生命的分布模式至关重要。蓝细菌是第一个建立产氧光合作用的谱系。蓝藻光合作用捕获太阳能，但有产生过氧化氢等活性氧的风险。能够处理细胞内活性氧分子的细胞过程的发展是蓝藻光合作用进化的关键。这个 EAGER 项目将测试一个有趣的假设，即蓝藻为何会产生蓝藻毒素，它们的功能是隔离过氧化氢，或以其他方式将其转化为非反应性形式。在该项目中，将比较有毒和无毒蓝藻菌株的过氧化氢产量。一种新的过氧化氢微传感器将用于检查稀表层湖水中过氧化氢的微观分布，以确定它是否与产生毒素的蓝细菌的丰度成反比（与假设一致）。最后，研究将确定是否可以通过添加α-酮酸来清除细胞产生的过氧化氢来提高在培养物中分离和培养新型蓝细菌的能力。

项目成果

Wetland management using microbial indicators

• DOI: 10.1016/j.ecoleng.2017.07.022
• 发表时间: 2017-11
• 期刊: Ecological Engineering
• 影响因子: 3.8
• 作者: H. Urakawa;A. Bernhard

Stress response of a marine ammonia-oxidizing archaeon informs physiological status of environmental populations

• DOI: 10.1038/ismej.2017.186
• 发表时间: 2017-10
• 期刊: The ISME Journal
• 作者: W. Qin;Shady A. Amin;Rachel A Lundeen;K. Heal;Willm Martens-Habbena;S. Turkarslan;H. Urakawa;Kyle C Costa;E. Hendrickson;Tony Wang;David AC Beck;Sonia M. Tiquia-Arashiro;F. Taub;Andrew D Holmes;Neeraja Vajrala;P. Berube;Todd M Lowe;James W. Moffett;A. Devol;N. Baliga;D. Arp;L. Sayavedra-Soto;M. Hackett;E. Armbrust;A. Ingalls;David A. Stahl

Ecological response of nitrification to oil spills and its impact on the nitrogen cycle

• DOI: 10.1111/1462-2920.14391
• 发表时间: 2018-10
• 期刊: Environmental Microbiology
• 影响因子: 5.1
• 作者: H. Urakawa;Suja S. Rajan;M. Feeney;P. Sobecky;B. Mortazavi

Hydrogen peroxide measurements in subtropical aquatic systems and their implications for cyanobacterial blooms

• DOI: 10.1016/j.ecoleng.2019.07.011
• 发表时间: 2019-11
• 期刊: Ecological Engineering
• 影响因子: 3.8
• 作者: Luka K. Ndungu;J. H. Steele;Taylor L. Hancock;Richard D. Bartleson;E. Milbrandt;M. Parsons;H. Urakawa-H.

Complete Genome Sequence of Microcystis aeruginosa FD4, Isolated from a Subtropical River in Southwest Florida

• DOI: 10.1128/mra.00813-20
• 发表时间: 2020-09
• 期刊: Microbiology Resource Announcements
• 影响因子: 0.8
• 作者: H. Urakawa;Taylor L. Hancock;J. H. Steele;Elizabeth K. Dahedl;Haruka E. Urakawa;Luka K. Ndungu;Lauren E. Krausfeldt;B. Rosen;J. Lopez