Use of Biomarkers of Oxidative Stress and Genotoxity in Allium cepa for Evaluation of Aquatic Pollution
Geremias, R.1; Bortolotto, T.2; Teixeira, G.A.2; Felipe, K.B.3; Fachini, J.M.3; Ávila, T.V.3; Wilhelm-Filho, D.4; Laranjeira, M.C.M.1; Pedrosa, R.C.3; Fávere, V.T.1
1Depto de Química, CFM, UFSC, SC; 2Depto de Ciências Biológicas, UNESC, SC; 3Depto de Bioquímica, CCB, UFSC, SC; 4Depto Ecologia-Zoologia, CCB, UFSC, SC
Allium cepa has been used as a bioindicator organism in the evaluation of ambient contamination because it presents fast cellular proliferation and growth, an important cellular differentiation and it is constituted of eukaryotic cells. This work proposed to evaluate biomarkers of oxidative stress and genotoxity in Allium cepa exposed to contaminated aquatic environments (samples of acid coal mine drainage-AMD). It was determined pH and the concentration of Al, Fe, Mn, Zn, Cu, Cd, Pb and SO4-2 in AMD. Allium cepa (n = 6) was exposed to AMD (10% of dilution) and to mineral water as negative control (NC) for 7 days. In the end of the exposition, it was evaluated the percentage of inhibition of the growth of roots and the fragmentation of DNA (Comet Assay) by the damage index (DI) in the meristematic cells. Also, it was evaluated the reduced glutathione levels (GSH), lipoperoxidation of membranes (TBARS), carbonylated protein (CP) and the catalase activity (CAT) in stem. The results was showed that AMD presented expressive acidity (pH = 2.80) and high concentration of Al (30.60 mg L-1), Fe (15.88 mg L-1), Mn (11.43 mg L-1) and SO4-2 (2,175 mg L-1). It was observed significant inhibition of the growth in ADM-exposed A. cepa’s roots (93.14%) when it was compared to the NC. Also, the statistical analyses (P<0.05) was showed that DNA fragmentation (ID = 232.4 ± 17.4), the GSH (0.908 ± 0.119 mM.g-1) and TBARS levels (64.0 ± 5.38 ηmol.g-1) and the CAT activity (61.03 ± 6.71 µmol.min-1.g-1) were increased significantly in AMD-exposed A. cepa’s stems when they were compared to NC (DI = 141.4 ± 8.76; GSH = 0.319 ± 0.079 mM.g-1; TBARS = 10.19 ± 4.52 ηmol.g-1; CAT = 30.79 ± 9.64 µmol.min-1.g-1). Curiously, there was not significant difference in the CP levels between the ADM-exposed group (37.838 ± 9.623 µmol.mg-1) and the NC (23.939 ± 4.007 µmol.mg-1). In conclusion, the indicators of oxidative stress and genotoxity in Allium cepa are able to distinguish contaminated aquatic environments to uncontaminated. They can consist important molecular tools for biomonitoring these environments
|