Photoinactivation and Photoreactivation of Constitutive and Adaptive Respiratory Systems of Azotobacter

摘要

The study was designed to elucidate the effects of ultraviolet and visible radiations on the functional oxidative adjustments of the bacterium, Azotobacter agile. The activities of adaptive and constitutive oxidation systems of azotobacter cells were found to be inhibited by ultraviolet irradiation. This inhibition could be reversed by exposing the irradiated cells to visible light. It is speculated that the normal steric orientation of respiratory enzymes within the cell and/or permeability to acetic and succinic acid molecules depends on the integrity of certain purine and pyrimidine structures of the cell. Absorption of ultraviolet radiation by these structures may result in their modifications and a consequent diminution of adaptive and oxidative activity. The subsequent absorption of visible radiation by the inactivated cells may result in a rearrangement of enzyme structure and/or permeability barriers with a consequent restoration of respiratory activity. The observation of the photoinactivation and photoreactivation of both constitutive and adaptive respiratory systems represents a new parameter in the study of functional adaptations, and photoinactivation and reactivation phenomena. (Author)