title: The respiratory chain is the cell's Achilles' heel during UVA inactivation in Escherichia coli.
abstract: Solar disinfection (SODIS) is used as an effective and inexpensive tool to improve the microbiological quality of drinking water in developing countries where no other means are available. Solar UVA light is the agent that inactivates bacteria during the treatment. Damage to bacterial membranes plays a crucial role in the inactivation process. This study showed that even slightly irradiated cells (after less than 1 h of simulated sunlight) were strongly affected in their ability to maintain essential parts of their energy metabolism, in particular of the respiratory chain (activities of NADH oxidase, succinate oxidase and lactate oxidase were measured). The cells' potential to generate ATP was also strongly inhibited. Many essential enzymes of carbon metabolism (glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase and malate dehydrogenase) and defence against oxidative stress (catalases and glutathione-disulfide reductase) were reduced in their activity during SODIS. The work suggests that damage to membrane enzymes is a likely cause of membrane dysfunction (loss of membrane potential and increased membrane permeability) during UVA irradiation. In this study, the first targets on the way to cell death were found to be the respiratory chain and F(1)F(0) ATPase.
authors.affiliation: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland.|Eawag, Swiss Federal Institute of Aquatic Science and Technology, PO Box 611, CH-8600 Dübendorf, Switzerland.
authors.forename: Franziska
authors.initials: F
authors.lastname: Bosshard
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, PO Box 611, CH-8600 Dübendorf, Switzerland.
authors.forename: Margarete
authors.initials: M
authors.lastname: Bucheli
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, PO Box 611, CH-8600 Dübendorf, Switzerland.
authors.forename: Yves
authors.initials: Y
authors.lastname: Meur
authors.affiliation: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland.|Eawag, Swiss Federal Institute of Aquatic Science and Technology, PO Box 611, CH-8600 Dübendorf, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Egli
mesh_terms: D004579:Electron Transport / Q000528:radiation effects; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects*; D029968:Escherichia coli Proteins / Q000378:metabolism; D050296:Microbial Viability / Q000528:radiation effects*; D013472:Sunlight; D014466:Ultraviolet Rays
chemical_list: D029968:Escherichia coli Proteins