Metabolomics to assess oxidative stress in Chlamydomonas reinhardtii

A wide variety of chemicals displaying various modes of action induce the formation of reactive oxygen species or oxidative stress. Oxidative stress is of special importance for photo­synthesizing organisms like the green alga Chlamydomonas reinhardtii that harvest light for carbon fixation. If the balance between light harvesting and energy utilization is upset, then surplus reactive oxygen species (ROS) can be produced that will cause damage to DNA, RNA, proteins and lipids. However, despite a wealth of data on chemical, physical and biological stressors, on toxicological pathways and concentration-dependent responses, biochemical pathways relating oxidative stress to short- or long-term damaging effects are still unknown. Metabolomic profiling and targeted metabolomics will help obtain a better understanding of oxidative stress response, and help linking molecular modes of action to physiological endpoints. The great advantage is that a metabolome reacts fast, compared to physiological endpoints, making diagnostic biomarkers, identified by metabolomics profiling, ideal for predicting phenotypic properties long before these features become apparent.

For this we have started to

• establish global and targeted metabolomics at Eawag
• map the integrative metabolomic response of Chlamydomonas reinhardtii to ROS inducing chemicals and oxidative stress (global profiling) and identify the key response mechanisms
• compare the metabolomic profile generated after short- and long-term sublethal exposure to oxidative stressors (paraquat, norflurazon, Ag, Pb) and determine differences in profiles that would indicate different biochemical pathways being activated under short- and long-term exposure.

Data analysis will be aimed at identifying biochemical pathways and networks activated by oxidative stress and link those to physiological endpoints such as growth and photosynthetic activity, thus leading to a better understanding of oxidative stress response.

Funding

Eawag discretionary funds