DIONNE, S., J.A. GAGNÉ, D. GILBERT, C. ROULEAU, 2011. Processus consultatif scientifique régional sur l’examen du plan de suivi écologique de la zone de protection marine Estuaire du Saint-Laurent, 3-5 Mai 2011, Institut Maurice-Lamontagne, Mont-Joli, Qc ; Regional Science Advisory Process on the Review of the St. Lawrence Estuary Marine Protected Area Ecological Monitoring Plan, Mai 3-5, 2011, Maurice Lamontagne Institute, Mont-Joli, Qc. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2011/037, 18 p.

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PINHO, G.L.L., A. BIANCHINI, C. ROULEAU, 2011. Whole-body autoradiography : an efficient technique to study copper accumulation and body distribution in small organisms. Chemosphere, 85: 1-6.

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Copepods have been widely used to evaluate toxicity of metals present in marine environments. However, a technical difficulty is to understand the possible routes of metal uptake and to identify in which tissues or organs metals are being accumulated. Traditional techniques are hard to be employed once each organ has to be analyzed separately. Autoradiography is an alternative technique to circumvent this limitation, since metal distribution in tissues can be visualized and quantified, even in small organisms like copepods. In the present study, accumulation and distribution of ⁶⁴Cu in the copepod Calanus hyperboreus was studied using autoradiography. Copepods were exposed for 2 h to copper (2.3 mg L^-1; 1.08 MBq ⁶⁴Cu mg^-1 Cu) and then allowed to depurate for 2 h in clean seawater. Total ⁶⁴Cu was determined by gamma-spectrometry after a metal exposure and a depuration period. ⁶⁴Cu distribution was determined based on images generated by autoradiography. Metal accumulation was observed on all external surfaces of the copepods, being accumulated mostly on the ventral region, followed by dorsal, urossoma and internal regions. After depuration, radioactivity levels had a decrease in the sum of external body surface. Our results show that copper uptake by C. hyperboreus is fast and that a non-negligible proportion of the accumulated metal can reach internal tissues, which may lead to detrimental physiological effects. Moreover, whole-body autoradiography was demonstrated to be an efficient technique to study copper accumulation and body distribution in a very small organism such as the copepod C. hyperboreus.©2011 Elsevier Ltd.

VALDEZ DOMINGOS, F.X., C.A. OLIVEIRA RIBEIRO, É PELLETIER, C. ROULEAU, 2011. Tissue distribution and depuration kinetics of waterborne 14C-labeled light PAHs in mummichog (Fundulus heteroclitus). Environ. Sci. Technol., 45(7): 2684-2690.

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Light polycyclic aromatic hydrocarbons (PAHs) of petrogenic origin are commonly found in estuaries and coastal areas. Though they are known to be toxic to fish, little is known about their uptake and tissue distribution. This paper reports on the results of a study on uptake, elimination, and tissue distribution of three waterborne ¹⁴C-labeled PAHs in the mummichog, Fundulus heteroclitus, using whole-body autoradiography. After a 24 h exposure to 1 μCi•3 L^–1 of ¹⁴C-naphthalene, ¹⁴C-1-naphthol, and ¹⁴C-phenanthrene, fish were transferred to clean water and tissue distribution examined after 0, 1, 3, 7, 14, and 21 days of depuration. All compounds were readily accumulated by fish and were also rapidly eliminated (t_0.5 range = 1.1 to 3.0 days). Most of the radioactivity in naphthalene- and phenanthrene-treated fish was found in gall bladder >> liver > intestinal lumen. In naphthol-exposed fish, an important labeling of some brain areas was observed. Brain of naphthalene-exposed fish was also labeled after 24 h depuration, indicating that exposure to naphthalene may result in metabolite accumulation in the brain. This is the first study showing that naphthalene, naphthol, and/or unidentified metabolite(s) can accumulate in brain tissues, which may impair normal brain function.©2011 American Chemical Society

AL-SID-CHEIKH, M., É. PELLETIER, C. ROULEAU, 2011. Synthesis and characterization of [110mAg]-nanoparticles with application to whole-body autoradiography of aquatic. Appl. Radiat. Isot., 69(10): 1415-1421.

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Silver nanoparticles (AgNp) were synthesized using aqueous solution of silver nitrate ([^110mAg]NO₃) with poly(allylamine) as a reducing agent and a stabilizer of the AgNp suspension. Nanoparticles were characterized by absorption spectroscopy, particle size analysis, atomic force microscopy (AFM), and transmission (TEM) electron microscopy. Different size nanoparticles (10–30 nm and 70–90 nm) were obtained by varying the polymer concentration and reaction time. The application of [^110mAg]AgNP to environmental studies, using nuclear techniques such as in vivo gamma counting and whole-body autoradiography, is demonstrated and discussed.©2011 Elsevier Ltd.

LACOUE-LABARTHE, T., R. VILLANUEVA, C. ROULEAU, F. OBERHÄNSLI, J.-L. TEYSSIÉ, R. JEFFREE, P. BUSTAMANTE, 2011. Radioisotopes demonstrate the contrasting bioaccumulation capacities of heavey metals in embryonic stages of cephalopod species. PLoS ONE, 6(11): 1-5 art no e27653.

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Cephalopods play a key role in many marine trophic food webs and also constitute alternative fishery resources in the context of the ongoing decline in finfish stocks. Most coastal cephalopod species of commercial importance migrate into shallow waters during the breeding season to lay their eggs, and are consequently subjected to coastal contamination. Eggs of common cuttlefish Sepia officinalis, European squid Loligo vulgaris, common octopus Octopus vulgaris and the sepiolid Rossia macrosoma were exposed during embryonic development to dissolved ^110mAg, ¹⁰⁹Cd, ⁶⁰Co, ⁵⁴Mn and ⁶⁵Zn in order to determine their metal accumulation efficiencies and distribution among different egg compartments. Cuttlefish eggs, in which hard shells enclose the embryos, showed the lowest concentration factor (CF) values despite a longer duration of exposure. In contrast, octopus eggs, which are only protected by the chorionic membrane, accumulated the most metal. Uptake appears to be linked to the selective retention properties of the egg envelopes with respect to each element. The study also demonstrated that the octopus embryo accumulated ^110mAg directly from the dissolved phase and also indirectly through assimilation of the contaminated yolk. These results raise questions regarding the potential contrasting vulnerability of early life stages of cephalopods to the metallic contamination of coastal waters.©2011 PLoS ONE

BEACH, D.G., M.A. QUILLIAM, C. ROULEAU, R.P. CROLL, J. HELLOU, 2010. Bioaccumulation and biotransformation of pyrene and 1-hydroxypyrene by the Marine Whelk Buccinum undatum. Environ. Toxicol. Chem., 29(4): 779-788.

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The fates of a phenolic contaminant and its hydrocarbon precursor have rarely been compared, especially in an invertebrate species. Two groups of i>Buccinum undatum were exposed to equimolar amounts of pyrene and 1-hydroxypyrene over 15 d through their diets. Tissue extracts from the muscle and visceral mass were analyzed by liquid chromatography with fluorescence and mass spectrometry detection. Nine biotransformation products were detected in animals from both exposures. These included 1-hydroxypyrene, pyrene-1-sulfate, pyrene-1-glucuronide, pyrene glucose sulfate, two isomers each of pyrenediol sulfate and pyrenediol disulfate, and one isomer of pyrenediol glucuronide sulfate. These compounds represent a more complex metabolic pathway for pyrene than is typically reported. Diconjugated metabolites were as important in animals exposed to pyrene as in those exposed to 1-hydroxypyrene. Biotransformation products represented >90 % of the material detected in the animals and highlight the importance of analyzing metabolites when assessing exposure. A mean of only 2 to 3 % of the body burden was present in muscle compared with the visceral mass of both groups. The analytical methods were sufficiently sensitive to detect biotransformation products both in laboratory control whelks and in those sampled offshore. The tissue distribution of [¹⁴C]pyrene was also studied by autoradiography. Radioactivity was present primarily in the digestive and excretory system of the whelks and not in the gonads or muscle tissue.©2009 SETAC

ZUYKOV, M., E. PELLETIER, C. ROULEAU, L. POPOV, S.W. FOWLER, M. ORLOVA, 2009. Autoradiographic study on the distribution of 241Am in the shell of the freshwater Zebra Mussel Dreissena polymorpha. Microchim. Acta, 167(3-4): 173-178.

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Autoradiography was used to identify α-track distributions in a series of shell sections from live mussels Dreissena polymorpha Pallas and dissected shells of dead mussels obtained from laboratory experiments using relatively high concentrations of ²⁴¹Am in the exposure media, a required condition for successful use of this autoradiographic technique. A comparable distribution of α-tracks was recorded on autoradiographs from both live and dead shells suggesting that metabolism does not lead to any sizable changes in the process of ²⁴¹Am adsorption (present in the extrapallial fluid) onto the inner surface of shell. Autoradiographs showed a preferential accumulation of ²⁴¹Am in the organic periostracum, whereas the outer and inner shell layers were characterized by a relatively low α-tracks density. No α-tracks were observed in the central part of the shell in any of the samples. These observations will be useful for the development of a general model to explain bioaccumulation and biosorption processes of radionuclides into mollusk shells.©2009 Elsevier B.V.

LACOUE-LABARTHE, T., M. WARNAU, M. METIAN, F. OBERHÄNSLI, C. ROULEAU, P. BUSTAMANTE, 2009. Biokinetics of Hg and Pb accumulation in the encapsulated egg of the Common Cuttlefish Sepia officinalis : radiotracer experiments. Sci. Total Environ., 407(24): 6188-6195.

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Uptake and depuration kinetics of dissolved ²⁰³Hg and ²¹⁰Pb were determined during the entire embryonic development of the eggs of the cuttlefish, Sepia officinalis (50d at 17 °C). ²⁰³Hg and ²¹⁰Pb were accumulated continuously by the eggs all along the development time reaching load/concentration ratio (LCR) of 467 ± 43 and 1301 ± 126 g, respectively. During the first month, most of the 203Hg and 210Pb remained associated with the eggshell indicating that the latter acted as an efficient shield against metal penetration. From this time onwards, ²⁰³Hg accumulated in the embryo, indicating that it passed through the eggshell, whereas ²¹⁰Pb did not cross the chorion during the whole exposure time. It also demonstrated that translocation of Hg associated with the inner layers of the eggshell is a significant source of exposure for the embryo. This study highlighted that the maturing embryo could be subjected to the toxic effects of Hg in the coastal waters where the embryonic development is taking place.©2009 Elsevier B.V.

FROUIN, H., J. PELLERIN, M. FOURNIER, E. PELLETIER, P. RICHARD, N. PICHAUD, C. ROULEAU, F. GARNEROT, 2007. Physiological effects of polycyclic aromatic hydrocarbons on soft-shell clam Mya arenaria. Aquat. Toxicol., 82(2): 120-134.

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The aim of this study was to investigate the effects of polycyclic aromatic hydrocarbons (PAHs) on the physiological status of the bivalve Mya arenaria. Specimens were exposed to four different sources of PAHs: aluminium smelter soot, sediment from an industrial discharge pound, charcoal fine particles and dietary PAHs assessed by feeding clams with phytoplankton freshly impregnated with dissolved PAHs. The exposure period lasted 30 days and bivalves were let to recover for an additional 20 days. At days 8, 15, 30 and 50, immune parameters (phagocytic activity and efficiency) were monitored in haemocytes. Oxidative stress measures such as catalase and lipid peroxidation were quantified in digestive gland as well as concentrations of bioaccumulated PAHs. In a second experiment, clams were exposed to [¹⁴C]-pyrene via the phytoplankton, and the tissue distribution of radiolabelled compound was studied. Glycogen levels in gonad and digestive gland were also measured and gametogenesis stages were investigated. Results showed a high bioaccumulation in clams exposed to dietary PAHs and contaminated sediments. Tissue distribution of [¹⁴C]-pyrene revealed that the radiolabelled compound persisted mainly in the gonad during 14 days. A decrease of phagocytosis was observed in contaminated male clams. The lipid peroxidation (malondialdehyde) was found to increase in the digestive gland tissues of clams exposed to dietary PAHs, smelter soot and discharge, but no differences were observed in the catalase activity. A delay in gametogenesis occurred in all exposed males and in females contaminated with coke dust and dietary PAHs. Males were more sensitive than females to PAH exposure. A dysfunction in steroid synthesis is suspected to occur due to the exposure to all sources of PAHs. © 2007 Elsevier B.V. All rights reserved.

EDGINTON, A.N., C. ROULEAU, G.R. STEPHENSON, H.J. BOERMANS, 2007. 2,4-D butoxyethyl ester kinetics in embryos of Xenopus laevis: the role of the embryonic jelly coat in reducing chemical absorption. Arch. Environ. Contam. Toxicol., 52: 113-120.

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The role of the jelly coat in providing a protective barrier to chemical absorption was studied using the embryos of the amphibian, <iXenopus laevis. Embryos with or without a jelly coat were water exposed to the butoxyethyl ester of 2,4-dichlorophenoxyacetic acid (2,4-D BEE) and the rates of uptake, metabolism, distribution, and excretion were determined. The water uptake clearance rates were slower for embryos with a jelly coat (1.5-4.5 ml_water·g _embryo ^-1 ·h^-1 or 0.040-0.022 ml_water·h^-1 per embryo) in comparison to dejellied embryos (14-21 ml_water·g _embryo ^-1 ·h^-1 0.0066-0.021 ml_water·h_{water·h^-1 per embryo). This accounted for the much lower residues in embryos with a jelly coat than in dejellied embryos during 8 h of exposure. Despite quantitative differences in uptake, once 2,4-D BEE had entered the embryos, metabolism and distribution were similar between the two test groups. 2,4-D BEE was metabolized to 2,4-dichlorophenoxyacetic acid (2,4-D) with half-lives ranging from 35 to 42 minutes. The radioactive residues, as determined by whole body autoradiography, appeared throughout the embryo with a slight accumulation in the blastocoel. Furthermore, 35 % of the radioactive residues were located in the jelly coat and 65 % in the developing embryo. Based on a slower 2,4-D elimination in embryos with a jelly coat, the diffusive properties that decreased 2,4-D BEE uptake appeared to similarly decrease elimination of its metabolite. The common practice of removing jelly coats prior to embryonic amphibian toxicity studies, as in the widely used Frog Embryo Teratogenesis Assay-Xenopus</> (FETAX), is discouraged based on the kinetic differences observed in this study.© 2007 Springer Science+Business Media, Inc.}