| 19800687 |
Silva D, Cortez-Moreira M, Cunha Bastos VL, Cunha Bastos J, Martins Cortez C: The interaction of methyl-parathion with serum and albumin of the neo-tropical fish Piaractus mesopotamicus. Ecotoxicol Environ Saf. 2010 Jan;73(1):32-7. Epub 2009 Oct 3.
The interaction of methyl-parathion with serum and albumin of pacu, Piaractus mesopotamicus, was studied, using the fluorescence quenching technique. Pacu is a neo-tropical fish specie inhabitant of rivers from western regions of Brazil. Methyl-parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous pesticide still used in agriculture and fish farming in many countries. The quenching of fluorescence can be mathematically expressed by the Stern-Volmer equation to calculate quenching constants. Stern-Volmer curves analysis is able to give important information about the pesticide-albumin interaction. Our results showed that the serum quenching reached 10% when the molar ratio of pesticide/albumin was about 7:1 for the three temperatures of the experiment. For the pure albumin quenching of 10%, methyl-parathion concentrations were 6, 7 and 9 times higher than albumin at 20, 25 and 30 degrees C, respectively. The calculated Stern-Volmer constants at 25 degrees C were 9.73x10 (3)(+/-4.9x10 (2)) M (-1) for serum and 9.20x10 (3)(+/-2.0x10 (2)) M (-1) for albumin. It was observed that albumin quenching is the phenomenon contributing to the quenching of the pacu serum fluorescence for methyl-parathion concentration lower than 10microM, suggesting that the protein is the most important carrier for the pesticide in serum. |
177(2,2,4,7) |