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

点击翻译按钮获取中文摘要

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.