Received: 21 April, 2009 Accepted: 8 July, 2009

  Abstract

  Background & Aims: Dimethoate as an organophosphorus compound is commonly used for crop production which is neurotoxic in human. Pseudomonas family harbor organophosphate degrading plasmids have been known as tools for cleaning environmental pollutions.

  Materials & Methods: Pseudomonas Putida was isolated from contaminated soil being identified and optimally cultured in mineral medium and was enriched with dimethoate. Bacterial utilization of dimethoate was determined by acetylcholine esterase inhibition (toxicity). The degrading plasmids for hydrolytic enzymes were deleted by acridine orange and transferred from resistance to sensitive strain.

  Results : Dimethoate was optimally utilized at 0.8 g/L concentration in mineral solution. The maximum dimethoate concentration tolerate by this bacterium was up 4.0 g/L in nutrient broth. The bacterial growth increased more than 2 folds in medium containing dimethoate in comparison with inorganic phosphate. Total proteins’ content that increased up to 357 mg/L was used as a known neuro-toxicity marker. Acetylcholine esterase activity was decreased by dimethoate in concentrations of 0.2 - 2.0 g/L in linear order but the inhibitory effect of dimethoate residue decreased 50-95% in P. Putida culture containing 2.0 g/L dimethoate after 48 - 96 hrs respectively. The resistance strain was lost degrading plasmids by acridine orange. The resistance plasmids were also transferred to sensitive strains.

  Conclusion : The mentioned plasmids express organophosphorus degrading enzymes and are supposed as effective techniques for cleaning of organophosphorus compounds as anti-nerve poisons and may be applicator of adverse effects of organophosphoruse compounds by modern technologies.

  Keywords : Biodegradation, Dimethoate, Organophosphorus utilization, Anti acetyl choline esterase

  Address : Clinical Biochemistry Department, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran Tel: (+98 241) 4240300

  Email: nazarian@zums.ac.ir

  Source: UMJ 2009: 20(3): 240 ISSN: 1027-3727