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Biosensor of reactive oxygen species using E.Coli
Active oxygen (O2-) is produced from oxygen (O2) by receiving a single electron (e-). The 90% of the active oxygen produced in cells comes from electron transport system in mitochondria. Although most of active oxygen produced in this process is released as water (H2O) by receiving another electron, few of them are released to cytoplasm as active oxygen.
Active oxygen is very unstable and has high oxidizing power that is utilized as defense system against infected bacteria in vivo. However, excess active oxygen is also harmful to the organisms. It oxidizes nucleic acids, lipids or proteins that can damage cells and tissues. The damage could at least partially cause Parkinson’s disease, Alzheimer’s disease, diabetes, cancer and other diseases related to aging. Therefore development of sensitive and economical detecting system for active oxygen would help us to understand these diseases.
Although influence of active oxygen on ecosystem is not fully understood yet, excess active oxygen in environment is very likely harmful to organisms. To detect harmful substances in high sensitivity or to study their influence on ecosystem, we sometimes carry out bioassay, using organisms typically found in the environment. Different from chemical and physical detection system, the direct effects on the organisms can be tested by the bioassay. However, the sensitive and economical bioassay system to detect active oxygen in environment has not been developed yet.
The bacteria grow fast in the simple medium and we can cultivate it easily at low cost. Therefore our team aimed at developing the technique to detect active oxygen in vivo and to quantify oxidative stress in the environment by creating biosensor system using E.Coli.
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