Developmental instability is associated with estrogenic endocrine disruption in the Chilean native fish species, Trichomycterus areolatus.

Endocrine disrupting compounds (EDCs) are widespread contaminants that alter the normal functioning of the endocrine system. While they cause dysfunctions in essential biological processes, it is unclear whether EDCs also impact developmental stability. In the present study, we investigated the occurrence of estrogenic endocrine disrupting compounds in a small watershed of south-central Chile impacted by anthropogenic activities. Then, we assessed their relationship with internal levels of estrogenic active compounds and fluctuating asymmetry (FA), a proxy of developmental stability in organisms with bilateral symmetry, in a native fish species (Trichomycterus areolatus). Yeast estrogenic screen assays were performed to measure estrogenic activity in river sediments and in male fish tissues collected from 17 sites along the Chillán watershed, and geometric morphometrics used to estimate fluctuating asymmetry based on the shapes of 248 fish skulls. Estrogenic activity was detected both in sediments and male fish tissues at concentrations of up to 1005 ng and 83 ng 17ß-estradiol equivalent/kg dw, respectively. No significant correlation was found between the two. However, fish tissue estrogenicity, water temperature and dissolved oxygen explained >80% of the FA population variation. By showing a significant relationship between estrogenic activity and FA of T. areolatus, our results indicate that developmental stability can be altered by estrogenic endocrine disruption, and that FA can be a useful indicator of sub-lethal stress in T. areolatus populations.

Cloning and expression of a GST-pi gene in Mytilus galloprovincialis. Attempt to use the GST-pi transcript as a biomarker of pollution.

Glutathione S-transferase is involved in the detoxication of many chemical compounds. Northern blot analysis of mRNA GST gene from the mussel Mytilus galloprovincialis shows the presence of a transcript of 850 bp (GenBank accession no. Gi:22094808 and AF527010). The cDNA cloned sequence is constituted by an ORF of 621 bp encoding for a protein of 23,700 Da present in the gills and digestive gland of M galloprovincialis. The sequence, called Mg (M. galloprovincialis) GST-p, is clearly related to the pi class GST. M. galloprovincialis treated with Cd (200 microg/L) and BaP (100 microg/L) or co-treated with Cd and BaP take up cadmium in the gills (16.2 +/- 4.2 and 12.6 +/- 1.2 microg Cd/g dry wt. after exposure to Cd and Cd + BaP, respectively) and in the digestive gland. The transcription of GST-pi gene, by semi-quantitative RT-PCR, shows the lowest value in the digestive glands of mussels exposed to BaP, whereas the treatment with cadmium and the co-treatment with cadmium and BaP evoke GST-pi gene expression higher than controls. Mussels collected from six sites along the south coast of Portugal show different GST-pi transcription levels, some of which are related to their pollutant content.

Metal bioaccumulation and metallothionein concentrations in larvae of Crassostrea gigas.

Larval stages of bivalve molluscs are highly sensitive to pollutants. Oysters from a hatchery from Normandy (English Channel) were induced to spawn, and fertilized eggs were exposed to copper or cadmium for 24 h. Metal accumulation (from 0.125 to 5 microg Cu L(-1) and from 25 to 200 microg Cd L(-1)) and MT concentrations were measured in larvae. Compared to controls, larvae accumulated copper and cadmium with an increase in MT concentrations particularly with cadmium (i.e. 130.96 ng Cu (mg protein)(-1) and 12.69 microg MT (mg protein)(-1) at 1 microg Cu L(-1) versus 23.19 ng Cu (mg protein)(-1) and 8.92 microg MT (mg protein)(-1) in control larvae; 334.3 ng Cd (mg protein)(-1) and 11.70 microg MT (mg protein)(-1) at 200 microg Cd L(-1) versus 0.87 ng Cd (mg protein)(-1) and 4.60 microg MT (mg protein)(-1) in control larvae). Larvae were also obtained from oysters of a clean area (Arcachon Bay) and a polluted zone (Bidassoa estuary) and exposed to copper in the laboratory, their MT concentration was measured as well as biomarkers of oxidative stress. Biomarker responses and sensitivity to copper for the larvae from Arcachon oysters were higher than for those from Bidassoa.