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Karray S, Marchand J, Geffard A, Rebai T, Denis F, Chénais B, Hamza-Chaffai A. Metal Contamination and Biomarkers in Cerastoderma glaucum: A Multi-level Approach. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2023; 84:484-503. [PMID: 37119272 DOI: 10.1007/s00244-023-00999-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 04/17/2023] [Indexed: 06/01/2023]
Abstract
In this study, we focused on evaluating the responses of the cockle, Cerastoderma glaucum to in situ exposures to metals at three sites in the Gulf of Gabes in the coastal zone of Tunisia differing in levels of metal contamination. Firstly, we examined the general physiological state of the organisms. Secondly, we evaluated the bioaccumulation of several metals (Cd, Cu, Zn, Ni) in the cockles. Thirdly, we focused on evaluating histologically changes in gametogenesis and sexual maturity of the organisms. Finally, we determined the expression of seven key genes encoding enzymes or proteins involved in responses to different types of environmental stressors. Results showed a decrease in the general physiological status of the cockles, including a reduced condition index, sex ratios skewed to females (70% and 80% females in the intermediate and the contaminated site, respectively) and greater mortalities in tests under anoxic conditions (i.e., stress on stress test) in cockles collected from the most contaminated site (LT50 = 2.88 days) compared to the cockles from the intermediate site (LT50 = 5 days) and the less contaminated site (LT50 = 6 days). Results for metal bioaccumulation showed that the levels of Cd, Cu, Zn and Ni in cockles were consistent with the contaminant gradient, with the highest levels in cockles from the most contaminated site (1.04; 4.92; 52.76 and 13.81 µg/g dw, respectively), followed by those from the intermediate site (0.34; 2.94; 36.94; 17.40 µg/g dw, respectively) and then the less contaminated site (0.065; 1.27; 21.62 and 5.40 µg/g dw, respectively). Results from the gametogenesis and maturity index showed few differences in the reproductive cycle of cockles collected from the three study sites. There were different patterns of gene expression that were divided into three groups in terms of responses: (1) expression of genes involved in metal detoxification, ATP Binding Cassette Subfamily B Member 1 (ABCB1) and metallothionein MT) and genes for superoxide dismutases (i.e., Mn SOD and CuZn SOD), which did not show any difference in their levels of expression; (2) heat shock protein 70 (HSP70) gene expression, which decreased in cockles according to the pollution gradient, and (3) expression of catalase (CAT) and cytochrome oxidase subunit 1 (COI) genes was threefold and 1000-fold higher in cockles from intermediate and most contaminated sites compared to the less contaminated site. Therefore, changes in overall physiological condition, sex ratios and expression of HSP70, CAT and COI genes may be appropriate biomarkers for in situ studies of the impacts of metals in cockles. However, these biomarkers should be coupled to proteomics studies.
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Affiliation(s)
- Sahar Karray
- Université du Maine - Le Mans, EA 2460 Mer Molécules Santé, Institut Universitaire Mer et Littoral - FR3473 CNRS, 72085, Le Mans Cedex, France.
- Laboratoire d'Ecotoxicologie Marine et Environnementale, Université de Sfax, Sfax, Tunisia.
| | - Justine Marchand
- Université du Maine - Le Mans, EA 2460 Mer Molécules Santé, Institut Universitaire Mer et Littoral - FR3473 CNRS, 72085, Le Mans Cedex, France
| | - Alain Geffard
- Université de Reims-Champagne Ardenne, EA 4689 Interactions Animal Environnement, BP 1039, 51687, Reims Cedex 2, France
| | - Tarek Rebai
- Laboratoire d'histologie à la faculté de médecine de Sfax, Université de Sfax, Sfax, Tunisia
| | - Françoise Denis
- Université du Maine - Le Mans, EA 2460 Mer Molécules Santé, Institut Universitaire Mer et Littoral - FR3473 CNRS, 72085, Le Mans Cedex, France
- UMR 7208 CNRS-MNHN-IRD-UPMC Biologie des Organismes et des Ecosystèmes Aquatiques (BOREA), Concarneau, France
| | - Benoît Chénais
- Université du Maine - Le Mans, EA 2460 Mer Molécules Santé, Institut Universitaire Mer et Littoral - FR3473 CNRS, 72085, Le Mans Cedex, France
| | - Amel Hamza-Chaffai
- Laboratoire d'Ecotoxicologie Marine et Environnementale, Université de Sfax, Sfax, Tunisia
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