Response Mechanisms to Oxidative Stress in Yeast and Filamentous Fungi

Oxidative stress is defined as a disturbance in the balance between the production of reactive oxygen species (ROS) and antioxidant defences, and thereby the ROS level exceeds the antioxidant capacity needed to maintain the intracellular redox environment in a reduced state. ROS are produced as a result of normal cellular metabolism as well as environmental factors. They display stronger reactivity than molecular oxygen and have the capacity to damage cellular components, which leads to disturbance in cellular homeostasis. The ability to detect environmental signals, perform signal transduction and trigger the response is a fundamental feature of all cells and organisms. This chapter reviews factors causing oxidative stress and the complex system of stress response including not only rapid transcriptional changes but also activation of the response to damage, which enables the cell to survive or trigger the cell death pathway.