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Surviving in a toxic world: transcriptomics and gene expression profiling in response to environmental pollution in the critically endangered European eel

Jose Martin Pujolar1*, Ilaria AM Marino1, Massimo Milan2, Alessandro Coppe1, Gregory E Maes3, Fabrizio Capoccioni4, Eleonora Ciccotti4, Lieven Bervoets5, Adrian Covaci56, Claude Belpaire7, Gordon Cramb8, Tomaso Patarnello2, Luca Bargelloni2, Stefania Bortoluzzi1 and Lorenzo Zane1

Author Affiliations

1 Department of Biology, University of Padova, I-35131, Padova, Italy

2 Department of Comparative Biomedicine and Food Science, University of Padova, I-35020, Legnaro, Italy

3 Laboratory of Biodiversity and Evolutionary Genomics, Katholieke Universiteit Leuven (KU Leuven), B-3000, Leuven, Belgium

4 Department of Biology, Università Roma Tor Vergata, I-00133, Rome, Italy

5 Department of Biology, University of Antwerp, B-2020, Antwerpen, Belgium

6 Toxicological Center, University of Antwerp, B-2610, Wilrijk, Belgium

7 Research Institute for Nature and Forest, B-1560, Groenendaal-Hoeilaart, Belgium

8 School of Medicine, University of St. Andrews, KY16 9TF, Fife, United Kingdom

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BMC Genomics 2012, 13:507  doi:10.1186/1471-2164-13-507

Published: 25 September 2012



Genomic and transcriptomic approaches have the potential for unveiling the genome-wide response to environmental perturbations. The abundance of the catadromous European eel (Anguilla anguilla) stock has been declining since the 1980s probably due to a combination of anthropogenic and climatic factors. In this paper, we explore the transcriptomic dynamics between individuals from high (river Tiber, Italy) and low pollution (lake Bolsena, Italy) environments, which were measured for 36 PCBs, several organochlorine pesticides and brominated flame retardants and nine metals.


To this end, we first (i) updated the European eel transcriptome using deep sequencing data with a total of 640,040 reads assembled into 44,896 contigs (Eeelbase release 2.0), and (ii) developed a transcriptomic platform for global gene expression profiling in the critically endangered European eel of about 15,000 annotated contigs, which was applied to detect differentially expressed genes between polluted sites. Several detoxification genes related to metabolism of pollutants were upregulated in the highly polluted site, including genes that take part in phase I of the xenobiotic metabolism (CYP3A), phase II (glutathione-S-transferase) and oxidative stress (glutathione peroxidase). In addition, key genes in the mitochondrial respiratory chain and oxidative phosphorylation were down-regulated at the Tiber site relative to the Bolsena site.


Together with the induced high expression of detoxification genes, the suggested lowered expression of genes supposedly involved in metabolism suggests that pollution may also be associated with decreased respiratory and energy production.

Anguilla anguilla; European eel; Transcriptome; Microarrays; Pollution