Cadmium-Induced Cyto- and Genotoxicity are Organ-Dependent in Lettuce

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Monteiro, C (Author) Other; Santos, C (Author) Other; Pinho, S (Author) Other; Oliveira, H (Author) Other; Pedrosa, T (Author) Other; Dias, MC (Author) Other

Journal

Title: Chemical Research in Toxicology

Vol. 25

Pages: 1423-1434

ISSN: 0893-228X

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 59 Citations

Scopus - 67 Citations

Other information

Authenticus ID: P-002-8C5

DOI: 10.1021/tx300039t

Abstract (EN): Cadmium is a priority pollutant. Its mechanisms and effects within different plant organs remain unclear. Here, cyto-genotoxicity biomarkers were evaluated in roots and leaves after Cd exposure (0, 1, 10, and 50 mu M) of the model crop Lactuca sativa L. (cv. "Reine de Mai"). Overall, superoxide dismutase (SOD) and catalase (CAT) activities were stimulated in leaves, where Cd accumulation was lower in comparison to that in roots. In roots, SOD and peroxidase (POX, APX) activities were stimulated. Moreover, in both organs glutathione reductase (GR) was not affected by Cd. Overall, the H2O2 content increased in both organs, while the total antioxidant capacity decreased in leaves and increased in roots with Cd concentrations. In both organs, lipid and protein oxidation rose with consequent increase of membrane permeability. Simultaneously, the comet assay showed that tail moment, tail length, and % tail DNA were maximum for 1 mu M. For 10 mu M, shorter tails were found suggesting induced Cd-DNA adducts that lead to DNA-DNA/DNA-protein cross-links, and/or formation of longer DNA fragments, and/or impairment of DNA repair mechanisms, while at 50 mu M, nucleoids sensitivity to the technique was evident. This result was consistent with the maximum micronuclei frequency found for the 10 mu M Cd dose in roots, suggesting that the surviving cells in this organ had an increase of mitotic catastrophe and that DNA repair systems for blocking cell cycle were dysfunctional. In lower Cd concentrations, root cells might have developed strategies to repair damaged DNA by blocking the cell cycle at specific checkpoints, thus avoiding mitotic catastrophe. Roots at 1 mu M showed a cell cycle blockage trend at the G(2) checkpoint, while those at higher concentrations presented S phase delay. We finally discuss a general model of Cd-organ interaction covering these cyto- and genotoxic effects and the potential use of this cultivar in phytoremediation strategies.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12