Genotoxic effects of p,p′‐DDT (1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane) and its metabolites in Zebra mussel (D. polymorpha) by SCGE assay and micronucleus test

Abstract

This is the first study to evaluate the potential genotoxicity of p,p'-DDT (1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane) and its metabolites (p,p'-DDD and p,p'-DDE) in the sentinel mollusc Zebra mussel (Dreissena polymorpha). DNA damage was measured using the single cell gel electrophoresis (SCGE) assay and the micronucleus test (MN test), which represent two of the more sensitive biomarkers for genotoxicity evaluation. Three different concentrations (0.1, 2, and 10 mug/L) of each compound were administered in water for 168 hr, maintaining mussels at constant laboratory conditions and collecting several specimens every 48 hr for biochemical analyses. At the same time, the bioaccumulation process and the concentration/effect relationship were checked by GC-MS/MS analyses of mussel soft tissues. The SCGE assay results showed a clear and significant (P < 0.05) relationship between DNA injuries and tested doses for all the homologues throughout the 7-day exposure period. The final DNA damage due to p,p'-DDE was almost double that of the other two homologues that showed the same toxicity pattern. The micronucleus frequency analysis confirmed the genotoxicity potential of the three homologues and p,p'-DDE showed the highest irreversible DNA damage. The capability of Zebra mussels to biotransform the administered compound in the other homologues was demonstrated by multiple regression analyses carried out between the MN frequencies and the concentrations of the different homologues in the mussel soft tissues. A greater genotoxic potential of the p,p'-DDE with respect to the other two chemicals was revealed.

Does zebra mussel (Dreissena polymorpha) represent the freshwater counterpart of Mytilus in ecotoxicological studies? A critical review

“…The Micronucleus (MN) test was the first genetic biomarker applied on the zebra mussel (Table 2), as reported by Mersch et al (1996b), who investigated the induction of micronuclei (MN) in D. polymorpha hemocytes and gill cells exposed to four different clastogen compounds (mitomycin C, bleomycin, dimethylarsinic acid and potassium chromate). Accordingly, further researches have been used this biomarker for testing genotoxicity of environmental pollutants (Table 2), showing significant increases of MN frequency in zebra mussel hemocytes caused by the exposure to various chemicals, such as B[a]P (Binelli et al, 2008b), p,p'-DDT and its p,p'-homologues (p,p'-DDD and p,p'-DDE, respectively; Binelli et al, 2008c), several PBDEs (BDE-47, -100, -154, -209; Riva et al, 2007;Parolini and Binelli, 2012a), personal care products (Binelli et al, 2008d), pharmaceuticals (Binelli et al, 2009a;Parolini et al, 2010Parolini et al, , 2011aParolini and Binelli, 2012b) and, recently, also some illicit drugs Parolini et al, 2013a;Binelli, 2013, 2014). MN test shows a fixed genetic damage, but the exposure to pollutants can also induce primary lesions, inducing DNA fragmentation as single or double strand breaks.…”

Toxicological effects of benzo(a)pyrene, DDT and their mixture on the green mussel Perna viridis revealed by proteomic and metabolomic approaches

“…BaP and DDT can result in several adverse biological effects in aquatic organisms, including bivalve molluscs (Binelli et al, 2008;Haritash and Kaushik, 2009;Maria et al, 2013). Green mussel, Perna viridis is widely distributed from oceanic waters to estuarine systems, and is a dominant inter-tidal species on polluted rocky shores.…”

Genotoxic Effect of Chronic Exposure to DDT on Lymphocytes, Oral Mucosa and Breast Cells of Female Rats

“…This test can also be used in those tissues where exfoliated cells have been obtained [14,15]. On the other hand, the practice of the single cell electrophoresis test (comet assay) has obtained an increasing acceptance in the genetic toxicology field [16,17]; some of its advantages are: damage detection at an individual cell level, high sensitivity (mainly under alkaline conditions), as well as the possibility to use enzymes or antibodies to detect specific types of damage [17,18]. Oxidative stress is one of the best known causes of cellular damage, mostly due to the formation of free radicals that damage cell DNA [19]; in recent years malondialdehyde (MDA) concentration has been used as an oxidative stress biomarker [20].…”