Access to the full text of the published version may require a subscription. Recent decades have seen a strong increase in the promise and uses of nanotechnology. This is correlated with their growing release in the environment and there is concern that nanomaterials may endanger ecosystems. Silver nanoparticles (AgNPs) have some of the most varied applications, making their release into the environment unavoidable. In order to assess their potential toxicity in aquatic environments, the acute toxicity of citrate-coated AgNPs to Daphnia magna was measured and compared to that of AgNO 3 . AgNPs were found to be ten times less toxic by mass than silver ions, and most of this toxicity was removed by ultracentrifuging. At the protein level, the two forms of silver had different impacts. RightsBoth increased protein thiol content, while only AgNP increased carbonyl levels. In 2DE of samples labelled for carbonyls, no feature was significantly affected by both compounds, indicating different modes of toxicity. Identified proteins showed functional overlap between the two compounds:vitellogenins (vtg) were present in most features identified, indicating their role as a general stress sensor.In addition to vtg, hemoglobin levels were increased by the AgNP exposure while 14-3-3 protein (a regulatory protein) carbonylation levels were reduced by AgNO 3 . Overall, this study confirms the previously observed lower acute toxicity of AgNPs, while demonstrating that the toxicity of both forms of silver follow somewhat different biologic pathways, potentially leading to different interactions with natural compounds or pollutants in the aquatic environment.

Human pharmaceuticals (e.g. the lipid regulator gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac) are an emerging environmental threat in the aquatic environment. This study aimed to evaluate sublethal effects of these two commonly found pharmaceuticals on the protein profiles of marine mussels (Mytilus spp.). Mytilus spp. was exposed to environmentally relevant and elevated concentrations (1 and 1000 µg/l respectively) of both drugs for 14 days. In addition, mussels were maintained for seven days post treatment to examine the potential of blue mussels to recover from such an exposure. Differential protein expression signatures (PES) in the digestive gland of mussels were obtained using two-dimensional gel electrophoresis after 7, 14, and 21 days of exposure. Twelve spots were significantly increased or decreased by gemfibrozil and/or diclofenac, seven of which were successfully identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. These proteins were involved in energy metabolism, oxidative stress response, protein folding, and immune responses. Changes in the PES over time suggested that mussels were still experiencing oxidative stress for up to seven days post exposure. In addition, a suite of biomarkers comprising glutathione transferase, lipid peroxidation, and DNA damage were studied. An oxidative stress response was confirmed by biomarker responses. To our knowledge, this is the first investigation using proteomics to assess the potential effects of human pharmaceuticals on a non-target species in an environmentally-relevant model. The successful application of this proteomic approach supports its potential use in pollution biomonitoring and highlights its ability to aid in the discovery of new biomarkers.

Developing innovative industries in rural communities requires researching valuable finished products using local natural resources and feasible equipment and technology. Resources like seaweed are popular in today's global cosmetic ingredient and biotechnology market and are commonly found growing in remote communities, making it an ideal opportunity for rural economic development. This study focuses on the antioxidantrich polyphenol compounds found in the seaweed species Ascophyllum nodosum, local to Que´bec's North Shore coastline. Different processing technologies were compared to optimize polyphenol yields, including different preservation methods as well as bioextraction techniques that are applicable and accessible to remote regions. Analyses of extracts were performed using different colorimetric assays to measure total polyphenols and phlorotannins, as well as to estimate antioxidant activity. Results from the study found that the samples immediately frozen displayed higher polyphenol concentration and the highest antioxidant activity. Analysis also showed that a microwaveassisted extraction method improved polyphenol yield efficiency for water extractions. However, the conventional solvent extraction method using 75% (v/v aq.) 1,3-propanediol solvent resulted in the highest phenolic content, totalling 9.8% (w/w) of its dry weight, and the optimal antioxidant activity.

The redox status of cells is involved in the regulation of several cellular stress-response pathways. It is frequently altered by xenobiotics, as well as by environmental stressors. As such, there is an increasing interest in understanding the redox status of proteins in different scenarios. Recent advances in proteomics enable researchers to measure oxidative lesions in a wide range of proteins. This opens the door to the sensitive detection of toxicity targets and helps decipher the molecular impact of pollutants and environmental stressors. The present study applies the measurement of protein carbonyls, the most common oxidative lesion of proteins, to gel-based proteomics in Daphnia magna. Daphnids were exposed to copper and paraquat, 2 well-known pro-oxidants. Catalase activity was decreased by paraquat, whereas global measurement of protein carbonyls and thiols indicated no change with treatment. Despite the absence of observed oxidative stress, 2-dimensional electrophoresis of the daphnid proteins and measurement of their carbonylation status revealed that 32 features were significantly affected by the treatments, showing higher sensitivity than single measurements. Identified proteins affected by copper indicated a decrease in the heat-shock response, whereas paraquat affected glycolysis. The present study demonstrates the applicability of redox-proteomics in daphnids, and indicates that the heat-shock response plays a counterintuitive role in metal resistance in daphnids.

Proteomics studies of kidney and related tissues have relevance to chronic kidney disease, and redox proteomics, in particular, represents an under-exploited toolkit for identification of novel biomarkers in this commonly occurring pathology.

Multixenobiotic resistance (MXR) proteins are known to be present in most living organisms, but only a few studies have been conducted on echinoderms and especially on their circulating cells, the coelomocytes. The objective of the present study was to investigate the presence of MXR activity in coelomocytes of the sea urchin Strongylocentrotus droebachiensis, the sea star Leptasterias polaris and the sea cucumber Cucumaria frondosa. Cells were exposed to fluorescent substrates (1 µM Rhodamine B [RB] The combination RB + MK induced a fluorescence increase in S. droebachiensis and C. frondosa coelomocytes. Finally, the combination CAM + MK induced a fluorescence diminution in L. polaris coelomocytes and S. droebachiensis vibratile cells. This difference in fluorescence incorporation indicated an MXR-like activity in coelomocytes, probably due to the presence of a P-glycoprotein (Pgp) and a multidrug resistance-associated protein (MRP)-like transporter. Western blot analysis was also carried out (Ab C219 and Ab C9) in order to detect potential MXR proteins using anti-MXR antibodies. Both Pgp and MRP were detected, but could not be further discriminated. MXR activity was clearly demonstrated in coelomocytes of S. droebachiensis, L. polaris and C. frondosa, although the identity of proteins responsible for this activity needs to be confirmed. KEY WORDS: Multixenobiotic resistance · MXR · Echinoderms · Coelomocytes · P-glycoprotein · Pgp · Multidrug resistance-associated proteins · MRPsResale or republication not permitted without written consent of the publisher Aquat Biol 12: 81-96, 2011 Pgp is known to be the primary active transporter of unmodified xenobiotics (Zaja et al. 2007), transporting mostly large and moderately hydrophobic cations (Litman et al. 2001). It is widely distributed in tissues and has a variety of physiological roles in healthy cells, such as lipid transport, intracellular cholesterol trafficking and the cytotoxic activity of NK and T cells (Johnstone et al. 2000). Among the family of MRPs, MRP1 facilitates the extrusion of numerous glutathione, glucuronate and sulphate conjugates. MRP1 is a ubiquitous protein taking part in various physiological functions including defence against xenobiotics and endogenous toxic metabolites, leukotrienemediated inflammatory responses, as well as protection from the toxic effect of oxidative stress (Bakos & Homolya 2007).A combination of substrates and inhibitors is often used to indicate MXR activity (Neyfakh 1988, Cornwall et al. 1995, Marin et al. 2004). Since some substrates and inhibitors are more specific to one MXR protein than to another, it is sometimes possible to discriminate the proteins involved. For example, Rhodamine B (RB) is often used as a Pgp substrate (Minier & Moore 1996, Reungpatthanaphong et al. 2003, Zaja et al. 2006) and a similar molecule, Rhodamine 123, is used as a Pgp-and MRP-like substrate (Hollo et al. 1996, Daoud et al. 2000. Calcein-AM (CAM) is also known as a substrate for both Pgp-like and MRP-like proteins,...