Ammonia triggers the promotion of oxidative stress in the aquatic macrophyte Myriophyllum mattogrossense

• Published in: Chemosphere (Oxford) 2007, Vol.66 (4), p.708-714
• Main Authors: Nimptsch, Jorge, Pflugmacher, Stephan
• Format: Article
• Language: English
• Subjects: Ammonia; Ammonia - toxicity; ammonium nitrogen; Animal, plant and microbial ecology; Antioxidants; Applied ecology; Aquatic macrophytes; Biological and medical sciences; catalase; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Enzyme Activators - toxicity; enzyme activity; Eutrophication; Eutrophication - drug effects; Fundamental and applied biological sciences. Psychology; glutathione; glutathione peroxidase; glutathione transferase; guaiacol peroxidase; lipid peroxidation; Lipid Peroxidation - drug effects; macrophytes; Myriophyllum; Myriophyllum mattogrossense; Oxidative stress; Oxidative Stress - drug effects; peroxidases; phytotoxicity; Plants - drug effects; Plants - enzymology; ROS; Water Pollutants, Chemical - toxicity; water pollution
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2006.07.064

The effect of increased ammonia content on sub-acute biochemical responses was assessed in the rooted submersed aquatic macrophyte Myriophyllum mattogrossense (common name: “Brazil Milfoil” or “Matogrosso Milfoil”), in a seven day aquarium experiment. The pH and temperature were monitored in order to determine the proportions of both ionized ( NH 4 + ) and un-ionized (NH 3) forms of ammonia. Specific activities of several enzymes such as catalase (CAT), guaiacol peroxidase (POD), glutathione peroxidase (GPx) and glutathione S-transferase (GST’s) were measured as well as the content of the soluble antioxidant glutathione and lipid peroxidation were determined as these parameters are considered as indicators of cell-level disorder. The results showed that ammonia is able to generate oxidative stress, expressed through an elevated GSH content and the enhancement of CAT, POD, GPx and GST’s activities in treatments with elevated ammonia content. As the toxic mechanism of ammonia is a complex phenomenon, this work adds an additional point of view to explain in parts the oxidative stress generating effect of ammonia promoting oxidative stress. Additionally the different modes of action proposed by other research groups are discussed, thus trying to combine the various points of view.