Johnson L R, Davenport R, Balbach H, Schaeffer D J
Department of Veterinary Biosciences, University of Illinois, Urbana 61801.
Ecotoxicol Environ Saf. 1994 Feb;27(1):34-49. doi: 10.1006/eesa.1994.1005.
2,4,6-Trinitrotoluene (TNT) and compounds associated with its production are toxic and phototoxic to a wide range of biota. The planarian Dugesia dorotocephala, but not Daphnia magna, metabolized TNT (1 mg/liter) to 4-amino-2,6-dinitrotoluene (4A; 0.4 mg/liter) and 2-amino-4,6-dinitrotoluene (2A; 0.2 mg/liter). Coexposure to near-ultraviolet (nuv) light enhanced the toxicity of 2A more than that of TNT and 4A. The toxicities of TNT, 4A, and 2A to Du. dorotocephala were all decreased by glutathione (GSH) conjugation. This suggests that all had mechanisms of toxic action involving formation of quinone-GSH conjugates. Dark and light mechanisms for TNT and 2A depended on GSH conjugation, but the specific mechanisms may be different for each compound. The dark and light mechanisms of toxic action for 4A appeared to be fundamentally different in that the dark toxic mechanism of action was less dependent on GSH conjugation. Hemolysis studies using sheep erythrocytes showed that the light-enhanced toxic mechanism of action for TNT, 2A, and/or 4A did not involve cellular membrane damage in response to nuv-induced anions.
2,4,6-三硝基甲苯（TNT）及其相关生产化合物对多种生物群落具有毒性和光毒性。涡虫杜氏阔头涡虫（Dugesia dorotocephala）能将TNT（1毫克/升）代谢为4-氨基-2,6-二硝基甲苯（4A；0.4毫克/升）和2-氨基-4,6-二硝基甲苯（2A；0.2毫克/升），而大型溞（Daphnia magna）则不能。与TNT和4A相比，同时暴露于近紫外（nuv）光下会增强2A的毒性。谷胱甘肽（GSH）结合作用会降低TNT、4A和2A对杜氏阔头涡虫的毒性。这表明它们都具有涉及醌-GSH结合物形成的毒性作用机制。TNT和2A的黑暗和光照毒性机制均依赖于GSH结合作用，但每种化合物的具体机制可能不同。4A的黑暗和光照毒性作用机制似乎有根本差异，即黑暗毒性作用机制对GSH结合作用的依赖性较小。使用绵羊红细胞进行的溶血研究表明，TNT、2A和/或4A的光增强毒性作用机制不涉及对nuv诱导阴离子的细胞膜损伤。
