Damage to DNA caused by UV-B radiation in the desert cyanobacterium Scytonema javanicum and the effects of exogenous chemicals on the process

• Published in: Chemosphere (Oxford) Vol. 88; no. 4; pp. 413 - 417
• Main Authors: Wang, Gaohong, Deng, Songqiang, Li, Cheng, Liu, Yongding, Chen, Lanzhou, Hu, Chaozhen
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2012; Elsevier
• Subjects: acids; adverse effects; Animal, plant and microbial ecology; Antioxidants; Antioxidants - pharmacology; Applied ecology; Biological and medical sciences; Cyanobacteria; Cyanobacteria - drug effects; Cyanobacteria - genetics; Cyanobacteria - metabolism; Cyanobacteria - radiation effects; Desert Climate; Desert soil cyanobacteria; deserts; DNA; DNA Damage; DNA, Bacterial; DNA, Bacterial - drug effects; DNA, Bacterial - genetics; DNA, Bacterial - radiation effects; drug effects; Ecotoxicology, biological effects of pollution; electron transfer; Exogenous chemicals; exposure duration; Fundamental and applied biological sciences. Psychology; General aspects; genetics; global positioning systems; glyphosate; Herbicides; Herbicides - toxicity; metabolism; pharmacology; photosynthesis; Photosynthesis - drug effects; Photosynthesis - radiation effects; radiation effects; reactive oxygen species; Reactive Oxygen Species - metabolism; ROS; Scytonema; Scytonema javanicum; Soil Microbiology; soil microorganisms; Superoxide Dismutase; Superoxide Dismutase - metabolism; toxicity; ultraviolet radiation; Ultraviolet Rays; Ultraviolet Rays - adverse effects; UV-B; MCPA-Na; DNA damage; SOD; GPS; MDA; ASC; NAC; UV-B; Herbicides; Exogenous chemicals; Desert soil cyanobacteria; Fv/Fm; ROS; Exogenous; Agricultural chemical product; Toxicity; UVB radiation; Pesticides; Genotoxicity; Herbicide; Soils; DNA; Cyanobacteria; Bacteria; Desert; Damage; Organic compounds
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2012.02.056

► UV-B radiation induced DNA damage in cyanobacteria. ► Antioxidants NAC and ASC decreased DNA damage and ROS under UV-B. ► Herbicides (GPS and MCPA) increased DNA damage and ROS under UV-B. ► DNA damage induction and chemicals effects were mediated by ROS regulation. Radiation with UV-B increased the damage to DNA in Scytonema javanicum, a desert-dwelling soil microorganism, and the level of damage varied with the intensity of UV-B radiation and duration of exposure. Production of reactive oxygen species (ROS) also increased because of the radiation. Different exogenous chemicals (ascorbate acid, ASC; N-acetylcysteine, NAC; glyphosate, GPS; and 2-methyl-4-chlorophenoxyacetic acid, MCPA-Na) differed in their effect on the extent of DNA damage and ROS production: whereas NAC and ASC protected the DNA from damage and resulted in reduced ROS production, the herbicides (GPS and MCPA-Na) increased the extent of damage, lowered the rate of photosynthesis, and differed in their effect on ROS production. The chemicals probably have different mechanisms to exercise their effects: NAC and ASC probably function as antioxidant agents or as precursors of other antioxidant molecules that protect the DNA and photosynthetic apparatus directly from the ROS produced as a result of UV-B radiation, and GPS and MCPA-Na probably disrupt the normal metabolism in S. javanicum to induce the leaking of ROS into the photosynthetic electron transfer pathway following UV-B radiation, and thereby damage the DNA. Such mechanisms have serious implications for the use of environment-friendly herbicides, which, because they can destroy DNA, may prove harmful to soil microorganisms.