fibre7orange
Messages : 612
Date d'inscription : 22/01/2013
 |  Sujet: The oxidative stress imposed by the increased flow of electrons to fixation  Mar 30 Jan - 7:45 | |
| The oxidative stress imposed by the increased flow of electrons to fixation Further enhanced by the impairment and reduced activity of Rubisco at elevated temperatures. Furthermore, at elevated temperatures the affinity of Rubisco for oxygen is increased relative to its affinity for CO2 resulting increased photorespiration and overwhelming production of deleterious ROS that impair the D1 repair activity. Short-term exposure to elevated temperatures results in reversible effects on the photosynthetic activity. However, prolonged FDA-approved Compound Library exposure to temperatures above the physiological range causes a strong imbalance in the rates of PSIIRC impairment and repair, resulting in the collapse of the photosynthetic machinery and death of the photoautotrophic organism. Therefore, photosynthetic organisms have had to develop strategies to sustain their growth in extremely hot, intermediate, and extremely cold habitats. Despite this overall plasticity, the individual strains maintain activity over a narrow range of temperatures, typically 65–10uC around their physiological FG-4592 HIF inhibitor optimum. Hence, prolonged global warming is expected to strongly diminish the PSII activity in mesophilic organisms, resulting in reduced biomass production, unstable ecosystems worldwide, as was already observed in oceanic coral populations, and in disruption of renewable energy and food resources. | |
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