Fate and effects of graphene oxide alone and with sorbed benzo(a)pyrene in mussels Mytilus galloprovincialis

Graphene oxide (GO) has gained a great scientific and economic interest due to its unique properties. As incorporation of GO in consumer products is rising, it is expected that GO will end up in oceans. Due to its high surface to volume ratio, GO can adsorb persistent organic pollutants (POPs), such as benzo(a)pyrene (BaP), and act as carrier of POPs, increasing their bioavailability to marine organisms. Thus, uptake and effects of GO in marine biota represent a major concern. This work aimed to assess the potential hazards of GO, alone or with sorbed BaP (GO+BaP), and BaP alone in marine mussels after 7 days of exposure. GO was detected through Raman spectroscopy in the lumen of the digestive tract and in feces of mussels exposed to GO and GO+BaP while BaP was bioaccumulated in mussels exposed to GO+BaP, but especially in those exposed to BaP. Overall, GO acted as a carrier of BaP to mussels but GO appeared to protect mussels towards BaP accumulation. Some effects observed in mussels exposed to GO+BaP were due to BaP carried onto GO nanoplatelets. Enhanced toxicity of GO+BaP with respect to GO and/or BaP or to controls were identified for other biological responses, demonstrating the complexity of interactions between GO and BaP.

Effects of microplastics alone or with sorbed oil compounds from the water accommodated fraction of a North Sea crude oil on marine mussels (Mytilus galloprovincialis)

Microplastics (MPs) can adsorb persistent organic pollutants such as oil hydrocarbons and may facilitate their transfer to organisms (Trojan horse effect). The aim of this study was to examine the effects of a 21 day dietary exposure to polystyrene MPs of 4.5 μm at 1000 particles/mL, alone and with sorbed oil compounds from the water accommodated fraction (WAF) of a naphthenic North Sea crude oil at two dilutions (25 % and 100 %), on marine mussels. An additional group of mussels was exposed to 25 % WAF for comparison. PAHs were accumulated in mussels exposed to WAF but not in those exposed to MPs with sorbed oil compounds from WAF (MPs-WAF), partly due to the low concentration of PAHs in the studied crude oil. Exposure to MPs or to WAF alone altered the activity of enzymes involved in aerobic (isocitrate dehydrogenase) and biotransformation metabolism (glutathione S-transferase). Prevalence of oocyte atresia and volume density of basophilic cells were higher and absorption efficiency lower in mussels exposed to MPs and to WAF than in controls. After 21 days MPs caused DNA damage (Comet assay) in mussel hemocytes. In conclusion, a Trojan horse effect was not observed but both MPs and oil WAF caused an array of deleterious effects on marine mussels at different levels of biological organization.

Cell and tissue level responses in mussels Mytilus galloprovincialis dietarily exposed to PVP/PEI coated Ag nanoparticles at two seasons

Silver nanoparticles (Ag NPs) are present in numerous consumer products due to their antimicrobial and other unique properties, thus concerns about their potential input into aquatic ecosystems are increasing. Toxicity of Ag NPs in waterborne exposed aquatic organisms has been widely investigated, but studies assessing the potential toxic effects caused after ingestion through the food web, especially at low realistic concentrations, remain scarce. Moreover, it is not well known whether season may influence toxic effects of Ag NPs. The main objective of this study was to determine cell and tissue level responses in mussels Mytilus galloprovincialis dietarily exposed to poly-N-vinyl-2-pirrolidone/polyethyleneimine (PVP/PEI) coated 5 nm Ag NPs for 1, 7 and 21 days both in autumn and spring. Mussels were fed every day with microalgae Isochrysis galbana exposed for 24 h to a low dose (1 μg Ag/L Ag NPs) in spring and to a higher dose (10 μg Ag/L Ag NPs) in spring and autumn. Mussels fed with microalgae exposed to the high dose accumulated Ag significantly after 21 days in both seasons, higher levels being measured in autumn compared to spring. Intralysosomal metal accumulation measured in mussel digestive gland and time- and dose-dependent reduction of mussels health status was similar in both seasons. DNA strand breaks increased significantly in hemocytes at both exposure doses along the 21 days in spring and micronuclei frequency showed an increasing trend after 1 and 7 days of exposure to 1 μg Ag/L Ag NPs in spring and to 10 μg Ag/L in both seasons. Values decreased after 21 days of exposure in all the cases. In conclusion, PVP/PEI coated 5 nm Ag NPs ingested through the food web were significantly accumulated in mussel tissues and caused adverse cell and tissue level effects both in autumn and in spring.

Bioaccumulation, cellular and molecular effects in adult zebrafish after exposure to cadmium sulphide nanoparticles and to ionic cadmium

Few works have addressed the effects provoked by the exposure to cadmium containing nanoparticles (NPs) on adult zebrafish (Danio rerio). We studied the effects of CdS NPs (5 nm) or ionic cadmium (10 μg Cd/L) after 3 and 21 d of exposure and at 6 months post-exposure (mpe). Acute toxicity was recorded after exposure to both forms of cadmium. Significant cadmium accumulation was measured in the whole fish after both treatments and autometallography showed a higher accumulation of metal in the intestine than that in the liver. Histopathological alterations, such as inflammation in gills and vacuolization in the liver, were detected after the exposure to both cadmium forms and, in a lower extent, at 6 mpe. X-ray analysis proved the presence of CdS NPs in these organs. The hepatic transcriptome analysis revealed that gene ontology terms such as "immune response" or "actin binding" were over-represented after 21 d of exposure to ionic cadmium respect to CdS NPs treatment. Exposure to CdS NPs caused a significant effect on pathways involved in the immune response and oxidative stress, while the exposure to ionic cadmium affected significantly pathways involved in DNA damage and repair and in the energetic metabolism. Oxidative damage to liver proteins was detected after the exposure to ionic cadmium, while a stronger destabilization of the hepatocyte lysosomal membrane was recorded under exposure to CdS NPs. In summary, although ionic cadmium provoked stronger effects than CdS NPs, both cadmium forms exerted an array of lethal and sublethal effects to zebrafish.

Impacts of dietary exposure to different sized polystyrene microplastics alone and with sorbed benzo[a]pyrene on biomarkers and whole organism responses in mussels Mytilus galloprovincialis

Due to their hydrophobicity and relatively large surface area, microplastics (MPs) can act as carriers of hydrophobic pollutants in the ocean and may facilitate their transfer to organisms. This study examined effects of dietary exposure to polystyrene MPs of 0.5 and 4.5 μm alone and with sorbed benzo[a]pyrene (BaP) on mussels Mytilus galloprovincialis in order to elucidate the effects of MP size and the presence of sorbed BaP on the organism. MPs were provided daily, mixed with algae, during 26 days at equivalent mass (0.058 mg/L), corresponding to 1000 particles/mL for 4.5 μm MPs and to 7.44 × 10⁵ particles/mL for 0.5 μm MPs. Effects were determined on early cellular biomarkers in hemocytes, structure and cell type composition of digestive tubules (DTs), histopathology and whole organism responses (condition index (CI), clearance rate (CR), food absorption efficiency (AE), respiration rate (RR) and scope for growth (SFG)). BaP concentrations in mussels increased with time, in particular when sorbed to smaller MPs. Large MPs were abundant in the lumen of stomach and DTs, but were also occasionally found within epithelial cells. Effects in all treatments increased with exposure time. MPs with sorbed BaP were more toxic than MPs alone according to hemocyte viability and catalase activity and to the quantitative structure of DT epithelium. Higher toxicity of small MPs compared to larger ones was recorded for DNA damage and cell composition of DTs. At tissue level a slight increase in prevalence of inflammatory responses occurred in all exposed groups. At whole organism level a compensatory effect was observed on absorption efficiency across MP treatments at day 26, resulting in increased SFG in mussels exposed to small MPs with sorbed BaP. This could be related to an increased energy need to deal with stress observed in biomarkers. Further work is required to understand the Trojan horse effect of a variety of plastic type, size, shape combinations together with a wide variety of pollutants.

Season influences the transcriptomic effects of dietary exposure to PVP/PEI coated Ag nanoparticles on mussels Mytilus galloprovincialis

Toxicity of AgNPs has been widely studied in waterborne exposed aquatic organisms. However, toxic effects caused by AgNPs ingested through the diet and depending on the season are still unexplored. The first cell response after exposure to xenobiotics occurs at gene transcription level. Thus, the aim of this study was to assess transcription level effects in the digestive gland of female mussels after dietary exposure to AgNPs both in autumn and in spring. Mussels were fed daily for 21 days with Isochrysis galbana microalgae previously exposed for 24 h to a dose close to environmentally relevant concentrations of 1 μg Ag/L PVP/PEI coated 5 nm AgNPs (in spring) and to a higher dose of 10 μg Ag/L of the same AgNPs both in autumn and in spring. After 1 and 21 days, mussels RNA was hybridized in a custom microarray containing 7806 annotated genes. Mussels were more responsive to the high dose compared to the low dose of AgNPs and a higher number of probes were altered in autumn than in spring. In both seasons, significantly regulated genes were involved in the cytoskeleton and lipid transport and metabolism COG categories, among others, while genes involved in carbohydrate transport and metabolism were specifically altered in autumn. Overall, transcription patterns were differently altered depending on the exposure time and season, indicating that season should be considered in ecotoxicological studies of metal nanoparticles in mussels.

Changes in protein expression in mussels Mytilus galloprovincialis dietarily exposed to PVP/PEI coated silver nanoparticles at different seasons

Potential toxic effects of Ag NPs ingested through the food web and depending on the season have not been addressed in marine bivalves. This work aimed to assess differences in protein expression in the digestive gland of female mussels after dietary exposure to Ag NPs in autumn and spring. Mussels were fed daily with microalgae previously exposed for 24 h to 10 μg/L of PVP/PEI coated 5 nm Ag NPs. After 21 days, mussels significantly accumulated Ag in both seasons and Ag NPs were found within digestive gland cells and gills. Two-dimensional electrophoresis distinguished 104 differentially expressed protein spots in autumn and 142 in spring. Among them, chitinase like protein-3, partial and glyceraldehyde-3-phosphate dehydrogenase, that are involved in amino sugar and nucleotide sugar metabolism, carbon metabolism, glycolysis/gluconeogenesis and the biosynthesis of amino acids KEGG pathways, were overexpressed in autumn but underexpressed in spring. In autumn, pyruvate metabolism, citrate cycle, cysteine and methionine metabolism and glyoxylate and dicarboxylate metabolism were altered, while in spring, proteins related to the formation of phagosomes and hydrogen peroxide metabolism were differentially expressed. Overall, protein expression signatures depended on season and Ag NPs exposure, suggesting that season significantly influences responses of mussels to NP exposure.

Dietary exposure of mussels to PVP/PEI coated Ag nanoparticles causes Ag accumulation in adults and abnormal embryo development in their offspring

Toxicity of silver nanoparticles (Ag NPs) to aquatic organisms has been widely studied. However, the potential toxic effects of Ag NPs ingested through the food web, especially at environmentally relevant concentrations, as well as the potential effects on the offspring remain unknown. The aims of this work were to screen the cytotoxicity of Poly N‑vinyl‑2‑pirrolidone/Polyethyleneimine (PVP/PEI) coated 5 nm Ag NPs in hemocytes exposed in vitro and to assess the effects of dietary exposure to Ag NPs on mussels growth, immune status, gonad condition, reproductive success and offspring embryo development. For this, mussels Mytilus galloprovincialis were fed daily with microalgae Isochrysis galbana previously exposed for 24 h to a dose close to environmentally relevant concentrations (1 μg Ag/L Ag NPs) and to a high dose of 10 μg Ag/L Ag NPs. After 24 h of in vitro exposure, Ag NPs were cytotoxic to mussel hemocytes starting at 1 mg Ag/L (LC50: 2.05 mg Ag/L). Microalgae significantly accumulated Ag after the exposure to both doses and mussels fed for 21 days with microalgae exposed to 10 μg Ag/L Ag NPs significantly accumulated Ag in the digestive gland and gills. Sperm motility and fertilization success were not affected but exposed females released less eggs than non-exposed ones. The percentage of abnormal embryos was significantly higher than in control individuals after parental exposure to both doses. Overall, results indicate that Ag NPs taken up through the diet can significantly affect ecologically relevant endpoints such as reproduction success and embryo development in marine mussels.

Bioaccumulation, tissue and cell distribution, biomarkers and toxicopathic effects of CdS quantum dots in mussels, Mytilus galloprovincialis

The bioaccumulation, cell, tissue distribution, and biological effects of 5 nm glutathione-capped CdS quantum dots (CdS QDs) in mussels was compared to bulk and aqueous Cd forms through a two-tier experimental approach. In the 1st tier, mussels were exposed for 3 d to 0.05, 0.5 and 5 mg Cd/l (QDs, bulk, aqueous), bioaccumulation, distribution and lysosomal responses were investigated. In the 2nd tier, mussels were exposed for 21 d to the same forms at the lowest effective concentration selected after Tier 1 (0.05 mg Cd/l), biomarkers and toxicopathic effects were investigated. Accumulation was comparable in QDs and aqueous Cd exposed mussels after 3 d. After 21 d, QDs exposed mussels accumulated less than mussels exposed to aqueous Cd and localised in the endo-lysosomal system and released to the alveoli lumen (21 d) after exposure to QDs and aqueous Cd. Intracellular levels of Cd increased on exposure to QDs and aqueous Cd, and to a lesser extent to bulk, and accompanied by the up-regulation of metallothionein 10 (1 d) and 20 (1, 21 d). Lysosomal membrane destabilisation depended on Cd²⁺ released by all forms but was marked after exposure to aqueous Cd (1 d). Toxicopathic effects (vacuolisation, loss of digestive cells and haemocytic infiltration) were evident after exposure to QDs (1 d) and aqueous Cd (21 d). Toxicity most likely depended on the ionic load resulting from Cd²⁺ release from the different forms of Cd; yet nanoparticle-specific effects of QDs cannot be disregarded.

Waterborne exposure of adult zebrafish to silver nanoparticles and to ionic silver results in differential silver accumulation and effects at cellular and molecular levels

Effects of silver nanoparticles (Ag NPs) on freshwater species have been reported in several studies, but there is not information on the potential long-term consequences of a previous exposure. In this work, we investigated the long-term effects of maltose-coated Ag NPs (20 nm) and of ionic silver (10 μg/L) after 21 days of exposure and at 6 months post-exposure (mpe) in adult zebrafish. Exposure resulted in significant silver accumulation in the whole body of fish exposed to ionic silver, but not in those exposed to Ag NPs. However, autometallography revealed metal accumulation in the liver and intestine of fish treated with the two silver forms and especially in the intestine of fish exposed to Ag NPs. X-ray microanalysis showed the presence of silver in gills, liver and intestine and of Ag NPs in gill and liver cells. Inflammation and hyperplasia were evident in the gills after both treatments and these histopathological conditions remained at 6 mpe. According to the hepatic transcriptome analysis, at 3 days ionic silver regulated a larger number of transcripts (410) than Ag NPs (129), while at 21 days Ag NPs provoked a stronger effect (799 vs 165 regulated sequences). Gene ontology terms such as "metabolic processes" and "response to stimulus" appeared enriched after all treatments, while "immune system" or "reproductive processes" were specifically enriched after the exposure to Ag NPs. This suggests that the toxicity of Ag NPs may not be solely related to the release of Ag ions, but also to the NP form. No evident effects were found on protein oxidation or on hepatocyte lysosomal membrane stability during exposure, but effects recorded on liver lysosomes and persistent damage on gill tissue at 6 mpe could indicate potential for long-term effects in exposed fish.

Toxicology tailored low density oligonucleotide microarray for the thicklip grey mullets (Chelon labrosus): Biomarker gene transcription profile after caging in a polluted harbour

In aquatic organisms inhabiting polluted waters genes are activated to build an adaptive/compensatory defence against the possible effects of pollutants. Such responses can be used as biomarkers of exposure to chemical compounds, outlining the molecular mechanisms activated under specific pollution scenarios. With the aim of exploiting such approach in environmental health assessment, toxicologically relevant gene fragments were sequenced in the thicklip grey mullet (Chelon labrosus) and a toxicologically tailored low-density (160 genes) oligonucleotide microarray was customised. The tool was validated comparing organ/sex specific gene expression profiles and characterising responses under laboratory exposure to model chemicals. Finally, juvenile mullets were caged in a polluted harbour and hepatic gene expression profiles analysed after 5 and 21 days of deployment. Cages were deployed in the inner (IH) and outer (OH) Pasaia harbour, Bay of Biscay. Mussels (Mytilus galloprovincialis) were also caged as biological matrix for chemical bioaccumulation analysis and stress biomarkers measurements. Slightly higher concentrations of chemicals (metals, tributyltin, PAHs, phthalates) were quantified in IH than in OH, fish bile metabolites also revealing higher availability of PAHs in IH. Lysosome membrane stability in mussels was reduced, indicating stress condition in both sites. The developed microarray discriminated mullets showing distinctive expression profiles depending on site and deployment time. Genes related to immune and hypoxia responses were regulated comparing IH and OH at day 5. Phase I and II biotransformation genes, such as cyp2, cyp3 and ugt, were up-regulated in IH, together with the aryl hydrocarbon receptor 2 (ahr2) and the ahr repressor. Similarly, TBT-binding proteins and genes involved in lipid metabolism (pparγ, cyp7) were up-regulated with deployment time. Even if nowadays higher throughput approaches for gene expression analyses are available, the developed mullet tool constitutes a comprehensive tool to assess molecular responses of mullets exposed to pollutants, although it remains to be explored whether it can be applied to assess pollutant exposure in active pollution monitorings and in environmental health assessment.

Changes in metallothionein transcription levels in the mussel Mytilus galloprovincialis exposed to CdTe quantum dots

Quantum dots (QDs) are a class of engineered nanoparticles (ENPs) with several biomedical, industrial and commercial applications. However, their metabolism and detoxification process in aquatic invertebrates and environmental health hazards remain unclear. This study investigate the transcriptional changes of metallothioneins (MTs) isoforms (mt10IIIa and mt20IV) induced by CdTe QDs, in comparison with its dissolved counterpart, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and to the same Cd concentration (10 µg Cd L^-1) of dissolved Cd for 14 days and mt transcription levels were measured by real time quantitative PCR (qPCR). Tissue specific mt transcription patterns were observed in mussels exposed to both Cd forms, wherein the gills were a more sensitive organ compared to the digestive gland. No significant changes were observed in mt10IIIa transcription levels in mussels exposed to both Cd forms. In contrast, transcription of mt20IV was tissue and exposure time dependent, with higher mt20IV mRNA levels in mussels exposed to QDs and dissolved Cd when compared to unexposed mussels. Multivariate analysis indicates particle-specific effects after 14 days of exposure and a dual role of MTs in the QD metabolism and in the protection against oxidative stress in mussels exposed to Cd-based ENPs.

Effects of dietary crude oil exposure on molecular and physiological parameters related to lipid homeostasis in polar cod (Boreogadus saida)

Polar cod is an abundant Arctic key species, inhabiting an ecosystem that is subjected to rapid climate change and increased petroleum related activities. Few studies have investigated biological effects of crude oil on lipid metabolism in this species, despite lipids being a crucial compound for Arctic species to adapt to the high seasonality in food abundance in their habitat. This study examines the effects of dietary crude oil exposure on transcription levels of genes related to lipid metabolism (peroxisome proliferator-activated receptors [ppar-α, ppar-γ], retinoic X receptor [rxr-β], palmitoyl-CoA oxidase [aox1], cytochrome P4507A1 [cyp7α1]), reproduction (vitellogenin [vtg-β], gonad aromatase [cyp19a1]) and biotransformation (cytochrome P4501A1 [cyp1a1], aryl hydrocarbon receptor [ahr2]). Exposure effects were also examined through plasma chemistry parameters. Additional fish were exposed to a PPAR-α agonist (WY-14,643) to investigate the role of PPAR-α in their lipid metabolism. The dose-dependent up-regulation of cyp1a1 reflected the activation of genes related to PAH biotransformation upon crude oil exposure. The crude oil exposure did not significantly alter the mRNA expression of genes involved in lipid homeostasis except for cyp7α1 transcription levels. Plasma levels of cholesterol and alanine transaminase showed significant alterations in fish exposed to crude oil at the end of the experiment. WY exposure induced a down-regulation of ppar-α, an effect contrary to studies performed on other fish species. In conclusion, this study showed clear effects of dietary crude oil exposure at environmentally relevant concentrations on xenobiotic biotransformation but revealed only weak alterations in the lipid metabolism of polar cod.

Acute toxicity, bioaccumulation and effects of dietary transfer of silver from brine shrimp exposed to PVP/PEI-coated silver nanoparticles to zebrafish

The extensive use and release to the aquatic environment of silver nanoparticles (NPs) could lead to their incorporation into the food web. Brine shrimp larvae of 24h showed low sensitivity to the exposure to PVP/PEI-coated Ag NPs (5nm), with EC₅₀ values at 24h of 19.63mgAgL^-1, but they significantly accumulated silver after 24h of exposure to 100μgL^-1 of Ag NPs. Thus, to assess bioaccumulation and effects of silver transferred by the diet in zebrafish, brine shrimp larvae were exposed to 100ngL^-1 of Ag NPs as an environmentally relevant concentration or to 100μgL^-1 as a potentially effective concentration and used to feed zebrafish for 21days. Autometallography revealed a dose- and time-dependent metal accumulation in the intestine and in the liver of zebrafish. Three-day feeding with brine shrimps exposed to 100ngL^-1 of Ag NPs was enough to impair fish health as reflected by the significant reduction of lysosomal membrane stability and the presence of vacuolization and necrosis in the liver. However, dietary exposure to 100μgL^-1 of Ag NPs for 3days did not significantly alter gene transcription levels, neither in the liver nor in the intestine. After 21days, biological processes such as lipid transport and localization, cellular response to chemical stimulus and response to xenobiotic stimulus were significantly altered in the liver. Overall, these results indicate an effective dietary transfer of silver and point out to liver as the main target organ for Ag NP toxicity in zebrafish after dietary exposure.

Integrative assessment of the effects produced by Ag nanoparticles at different levels of biological complexity in Eisenia fetida maintained in two standard soils (OECD and LUFA 2.3)

There is a potential risk to increase the release of silver nanoparticles (Ag NPs) into the environment: For instance. in soils receiving sludge models estimate 0.007 mg Ag NPs kg^-1 that will annually increase due to sludge or sludge incineration residues land-disposal. Thus, the concern about the hazards of nanosilver to soils and soil invertebrates is growing. Studies performed up to now have been focused in traditional endpoints, used limit range concentrations and employed different soil types that differ in physico-chemical characteristics. Presently, effects of Ag NPs have been measured at different levels of biological complexity in Eisenia fetida, exposed for 3 and 14 d to high but sublethal (50 mg Ag NPs kg^-1) and close to modeled environmental concentrations (0.05 mg Ag NPs kg^-1). Since characteristics of the exposure matrix may limit the response of the organisms to these concentrations, experiments were carried out in OECD and LUFA soils, the most used standard soils. High concentrations of Ag NPs increased catalase activity and DNA damage in OECD soils after 14 d while in LUFA 2.3 soils produced earlier effects (weight loss, decrease in cell viability and increase in catalase activity at day 3). At day 14, LUFA 2.3 (low clay and organic matter-OM-) could have provoked starvation of earthworms, masking Ag NPs toxicity. The concentration close to modeled environmental concentrations produced effects uniquely in LUFA 2.3 soil. Accurate physico-chemical characteristics of the standard soils are crucial to assess the toxicity exerted by Ag NPs in E. fetida since low clay and OM contents can be considered toxicity enhancers.

Hepatic gene transcription profiles in turbot (Scophthalmus maximus) experimentally exposed to heavy fuel oil nº 6 and to styrene

Oil and chemical spills in the marine environment, although sporadic, are highly dangerous to biota inhabiting coastal and estuarine areas. Effects of spilled compounds in exposed organisms occur at different biological organization levels: from molecular, cellular or tissue levels to the physiological one. The present study aims to determine the specific hepatic gene transcription profiles observed in turbot juveniles under exposure to fuel oil n °6 and styrene vs controls using an immune enriched turbot (Scophthalmus maximus) oligo-microarray containing 2716 specific gene probes. After 3 days of exposure, fuel oil specifically induced aryl hydrocarbon receptor mediated transcriptional response through up-regulation of genes, such as ahrr and cyp1a1. More gene transcripts were regulated after 14 days of exposure involved in ribosomal biosynthesis, immune modulation, and oxidative response among the most significantly regulated functional pathways. On the contrary, gene transcription alterations caused by styrene did not highlight any significantly regulated molecular or metabolic pathway. This was also previously reported at cell and tissue level where no apparent responses were distinguishable. For the fuel oil experiment, obtained specific gene profiles could be related to changes in cell-tissue organization in the same individuals, such as increased hepatocyte vacuolization, decrease in melano-macrophage centers and the regulation of leukocyte numbers. In conclusion, the mode of action reflected by gene transcription profiles analyzed hereby in turbot livers could be linked with the responses previously reported at higher biological organization levels. Molecular alterations described hereby could be preceding observed alterations at cell and tissue levels.

Effects of PVP/PEI coated and uncoated silver NPs and PVP/PEI coating agent on three species of marine microalgae

In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5nm Ag NPs and uncoated 47nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72h in artificial seawater, 47nm Ag NPs formed around 1400nm size aggregates while PVP/PEI coated 5nm Ag NPs reached around 90nm. Ag⁺ release in seawater was around 3% for 47nm Ag NPs and 30% for PVP/PEI coated 5nm Ag NPs. PVP/PEI coated 5nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics.

New Nuclear SNP Markers Unravel the Genetic Structure and Effective Population Size of Albacore Tuna (Thunnus alalunga)

In the present study we have investigated the population genetic structure of albacore (Thunnus alalunga, Bonnaterre 1788) and assessed the loss of genetic diversity, likely due to overfishing, of albacore population in the North Atlantic Ocean. For this purpose, 1,331 individuals from 26 worldwide locations were analyzed by genotyping 75 novel nuclear SNPs. Our results indicated the existence of four genetically homogeneous populations delimited within the Mediterranean Sea, the Atlantic Ocean, the Indian Ocean and the Pacific Ocean. Current definition of stocks allows the sustainable management of albacore since no stock includes more than one genetic entity. In addition, short- and long-term effective population sizes were estimated for the North Atlantic Ocean albacore population, and results showed no historical decline for this population. Therefore, the genetic diversity and, consequently, the adaptive potential of this population have not been significantly affected by overfishing.

Combined effects of thermal stress and Cd on lysosomal biomarkers and transcription of genes encoding lysosomal enzymes and HSP70 in mussels, Mytilus galloprovincialis

In estuaries and coastal areas, intertidal organisms may be subject to thermal stress resulting from global warming, together with pollution. In the present study, the combined effects of thermal stress and exposure to Cd were investigated in the endo-lysosomal system of digestive cells in mussels, Mytilus galloprovincialis. Mussels were maintained for 24h at 18°C and 26°C seawater temperature in absence and presence of 50 μg Cd/L seawater. Cadmium accumulation in digestive gland tissue, lysosomal structural changes and membrane stability were determined. Semi-quantitative PCR was applied to reveal the changes elicited by the different experimental conditions in hexosaminidase (hex), β-glucuronidase (gusb), cathepsin L (ctsl) and heat shock protein 70 (hsp70) gene transcription levels. Thermal stress provoked lysosomal enlargement whilst Cd-exposure led to fusion of lysosomes. Both thermal stress and Cd-exposure caused lysosomal membrane destabilisation. hex, gusb and ctsl genes but not hsp70 gene were transcriptionally up-regulated as a result of thermal stress. In contrast, all the studied genes were transcriptionally down-regulated in response to Cd-exposure. Cd bioaccumulation was comparable at 18°C and 26°C seawater temperatures but interactions between thermal stress and Cd-exposure were remarkable both in lysosomal biomarkers and in gene transcription. hex, gusb and ctsl genes, reacted to elevated temperature in absence of Cd but not in Cd-exposed mussels. Therefore, thermal stress resulting from global warming might influence the use and interpretation of lysosomal biomarkers in marine pollution monitoring programmes and, vice versa, the presence of pollutants may condition the capacity of mussels to respond against thermal stress in a climate change scenario.

Molecular cloning and measurement of telomerase reverse transcriptase (TERT) transcription patterns in tissues of European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua) during aging

Telomerase is a reverse transcriptase ribonucleoprotein that maintains the ends of linear chromosomes. This enzyme plays a major role in cell processes like proliferation, differentiation and tumorigenesis, being associated with aging and survival of species. In this study, the gene coding for TERT (Telomerase Reverse Transcriptase) of two commercial fish species, European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua), has been partially cloned. A fragment of 1581bp (hake) and 633bp (cod) showed high homology (identity 74%, query cover 99%, E-value=0) with known Perciformes TERT sequences. TERT transcription patterns were assessed by qRT-PCR in different tissues of hake (brain, ovary, testis, muscle, skin, gills, liver and kidney) and cod (brain, muscle and skin) of different sizes/ages in order to understand its role in the physiological aging of teleosts. TERT was found to be ubiquitously transcribed in all tissues and size/age groups studied in both species. Significantly higher relative transcription levels (p<0.05) were found with increasing size/age of M. merluccius in the kidney, muscle, skin and gonad, the latter exhibiting particularly high relative transcription levels. Male hakes showed higher TERT relative transcription levels in the brain, gonad and liver than females, although these differences were not statistically significant (p<0.05). In G. morhua, higher TERT relative transcription levels were recorded in the muscle and brain of fry and juvenile individuals. Therefore, TERT relative transcription pattern exhibited a higher telomerase demand in early developmental stages and also in mature stages, suggesting tissue renewal or regeneration processes as a conserved mechanism for maintaining long-term cell proliferation capacity and preventing senescence. Thus, it can be concluded that TERT relative transcription level was species and tissue specific and changed with the age of fishes.

Regulation of xenobiotic transporter genes in liver and brain of juvenile thicklip grey mullets (Chelon labrosus) after exposure to Prestige-like fuel oil and to perfluorooctane sulfonate

Xenobiotic transport proteins are involved in cellular defence against accumulation of xenobiotics participating in multixenobiotic resistance (MXR). In order to study the transcriptional regulation of MXR genes in fish exposed to common chemical pollutants we selected the thicklip grey mullet (Chelon labrosus), since mugilids are widespread in highly degraded estuarine environments where they have to survive through development and adulthood. Partial sequences belonging to genes coding for members of 3 different families of ATP binding cassette (ABC) transporter proteins (ABCB1; ABCB11; ABCC2; ABCC3; ABCG2) and a vault protein (major vault protein, MVP) were amplified and sequenced from mullet liver. Their liver and brain transcription levels were examined in juvenile mullets under exposure to perfluorooctane sulfonate (PFOS) and to fresh (F) and weathered (WF) Prestige-like heavy fuel oil for 2 and 16 days. In liver, PFOS significantly up-regulated transcription of abcb1, abcb11 and abcg2 while in brain only abcb11 was up-regulated. Both fuel treatments significantly down-regulated abcb11 in liver at day 2 while abcc2 was only down-regulated by WF. mvp was significantly up-regulated by F and down-regulated by WF at day 2 in the liver. At day 16 only a significant up-regulation of abcb1 in the F group was recorded. Brain abcc3 and abcg2 were down-regulated by both fuels at day 2, while abcb1 and abcc2 were only down-regulated by F exposure. After 16 days of exposure only abcb11 and abcg2 were regulated. In conclusion, exposure to organic xenobiotics significantly alters transcription levels of genes participating in xenobiotic efflux, especially after short periods of exposure. Efflux transporter gene transcription profiling could thus constitute a promising tool to assess exposure to common pollutants.

Copolymerization of acenaphthylene with methacrylic monomers

The copolymerization of acenaphthylene with methylmethacrylate, ethylmethacrylate, butylmethacrylete, iso-butylmethacrylate and cyclohexylmethacrylate has been carried out in tetrahydrofuran at 323 K and the composition of the copolymers has been determined by size exclusion chromatography using a double RI-UV detector system. Several methods have been applied to obtain the reactivity ratios of the copolymerization process. The glass transition temperature of the copolymers has been obtained by DSC and the thermal stability has been studied by thermogravimetry. Analysis of the degradation volatile products reveals that copolymers degrade mainly by depolymerization.

Reutilization of thermostable polyester wastes by means of agglomeration with phenolic resins

We report on the possibility of obtaining organic polymeric matrixes allowing the development of new high performance fire-resistant products by recycling downsized thermostable waste materials. Phenolic resins have been used as binders for recycled waste. Furthermore, considering that reinforced plastic triturations have superior properties (chemical, mechanical, water resistance, etc.) to wood agglomerates, significant advantages over conventional materials are anticipated. In summary, we propose a viable solution to some of the known problems caused by the consumption of wood and to the needs of strengthened plastic processing engineering. Using resins as a binder, several fire-resistant prototypes were prepared from polyester waste, and their mechanical properties, thermal stability, and fire-resistant properties were analyzed.

Effects of exposure to Prestige-like heavy fuel oil and to perfluorooctane sulfonate on conventional biomarkers and target gene transcription in the thicklip grey mullet Chelon labrosus

Thicklip grey mullets Chelon labrosus inhabit coastal and estuarine areas where they can be chronically exposed to commonly released pollutants such as polycyclic aromatic hydrocarbons (PAHs) and perfluorinated compounds. These pollutants can also originate from accidental spills, such as the Prestige oil spill in 2002, which resulted in the release of a heavy fuel oil that affected coastal ecosystems in the Bay of Biscay. Peroxisome proliferation (PP), induced biotransformation metabolism, immunosuppression and endocrine disruption are some of the possible biological effects caused by such chemicals. With the aim of studying the effects of organic toxic chemicals on such biological processes at the transcriptional and at the cell/tissue level, juvenile mullets were exposed to the typical mammalian peroxisome proliferator perfluorooctane sulfonate (PFOS), and to fresh (F) and weathered (WF) Prestige-like heavy fuel oil for 2 and 16 days. First, fragments of genes relevant to biotransformation, immune/inflammatory and endocrine disruption processes were cloned using degenerate primers. Fuel oil elicited a significant PP response as proved by the transcriptional upregulation of palmitoyl-CoA oxidase (aox1), peroxisome proliferator activated receptor alpha (pparalpha) and retinoic X receptor, by the AOX1 activity induction and by the increased peroxisomal volume density. PFOS only elicited a significant induction of AOX1 activity at day 2 and of PPARalpha mRNA expression at day 16. All treatments significantly increased catalase mRNA expression at day 16 in liver and at day 2 in gill. Cyp1a transcription (liver and gill) and EROD activity were induced in fuel oil treated organisms. In the case of phase II metabolism only hepatic glutathione S-transferase mRNA was overexpressed in mullets exposed to WF for 16 days. Functionally, this response was reflected in a significant accumulation of bile PAH metabolites. WF treated fish accumulated mainly high molecular weight metabolites while F exposure resulted in accumulation of mainly low molecular ones. Fuel oil significantly regulated immune response related complement component C3 and hepcidin transcription followed by a significant regulation of inflammatory response related apolipoprotein-A1 and fatty acid binding protein mRNAs at day 16. These responses were accompanied by a significant hepatic inflammatory response with lymphocyte accumulations (IRLA) and accumulation of melanomacrophage centers (MMC). PFOS did not elicit any transcriptional response in the studied biotransformation and immune related genes, although histologically significant effects were recorded in IRLA and MMC. A significant reduction of lysosomal membrane stability was observed in all exposed animals. No endocrine disruption effects were observed in liver while brain aromatase mRNA was overexpressed after all treatments at day 2 and estrogen receptor alpha was downregulated under WF exposure at day 16. These results show new molecular and cellular biomarkers of exposure to organic chemicals and demonstrate that in mullets PP could be regulated through molecular mechanisms similar to those in rodents, although the typical mammalian peroxisome proliferator PFOS and heavy fuel oil follow divergent mechanisms of action.

Tissue- and cell-specific expression of metallothionein genes in cadmium- and copper-exposed mussels analyzed by in situ hybridization and RT–PCR

Metallothioneins (MTs) are metal-inducible proteins that can be used as biomarkers of metal exposure. In mussels two families of MT isoforms (MT10 and MT20) have been characterized. In this study, mussels (Mytilus galloprovincialis) were exposed to 200 ppb Cd and 40 ppb Cu for 2 and 9 days to characterize the tissue and isoform specificity of metal-induced MT expression. Non-radioactive in situ hybridization demonstrated that both MT isoforms were mainly transcribed in digestive tubule epithelial cells, especially in basophilic cells. Weaker MT expression was detected in non-ciliated duct cells, stomach and gill epithelial cells, haemocytes, adipogranular cells, spermatic follicles and oocytes. RT-PCR resulted in cloning of a novel M. galloprovincialis isoform homologous to recently cloned Mytilus edulis intron-less MT10B isoform. In gills, Cd only affected MT10 gene expression after 2 days of exposure while increases in MT protein levels occurred at day 9. In the digestive gland, a marked increase of both isoforms, but especially of MT20, was accompanied by increased levels of MT proteins and basophilic cell volume density (Vv(BAS)) after 2 and 9 days and of intralysosomal metal accumulation in digestive cells after 9 days. Conversely, although metal was accumulated in digestive cells lysosomes and the Vv(BAS) increased in Cu-exposed mussels, Cu exposure did not produce an increase of MT gene expression or MT protein levels. These data suggest that MTs are expressed in a tissue-, cell- and isoform-specific way in response to different metals.

Cloning and expression pattern of peroxisomal enzymes in the mussel Mytilus galloprovincialis and in the thicklip grey mullet Chelon labrosus: generation of new tools to study peroxisome proliferation

Aquatic organisms living in coastal/estuarine areas show peroxisome proliferation after exposure to different environmentally relevant pollutants. In order to generate new tools to assess peroxisome proliferation in aquatic animals, peroxisomal enzymes were cloned using degenerate primers in the mussel Mytilus galloprovincialis and in the thicklip grey mullet Chelon labrosus. Fragments of catalase (CAT), thiolase (THIO), polyamine oxidase (POX) and xanthine oxidoreductase (XOR) were cloned and their expression pattern studied in different tissues by semi-quantitative RT-PCR. In mussels, CAT, THIO, POX and XOR were expressed in digestive gland, mantle and gills while in mullets CAT, THIO and POX were expressed in liver, spleen, brain, heart, muscle and gills. XOR was mainly expressed in liver and heart. Mature mullets showed the highest expression of peroxisomal enzymes in liver, spleen and brain, while in juveniles expression was mainly found in muscle tissues, liver and gills. Laboratory experiments of exposure to organic pollutants are being performed to study the usefulness of these tools to study peroxisome proliferation in pollution biomonitoring programmes.

Expression of peroxisome proliferator-activated receptors in zebrafish (Danio rerio) depending on gender and developmental stage

Peroxisome proliferator-activated receptors (PPARs) are members of the superfamily of nuclear hormone receptors involved in embryo development and differentiation of several tissues in mammals. The aim of the present study was to investigate the possible differential expression of the three PPAR subtypes (PPARalpha, PPARbeta, and PPARgamma) in relation to gender and developmental stage in zebrafish. For this purpose PPAR expression was assessed by immunohistochemistry in 7-day-old larvae, 1-month-old juveniles, and 1-year-old adults. Additionally, the activity of peroxisomal acyl-CoA oxidase (AOX), a gene regulated by PPARs, and the volume density of catalase-immunolabeled liver peroxisomes (V(VP)) was examined. No significant gender-related differences were detected in the tissue distribution of the three PPAR subtypes or in peroxisomal AOX activity and V(VP). The percentage of PPARbeta-positive hepatocytes was significantly higher in females than in males suggesting a specific regulatory role of this subtype in female zebrafish. The three PPAR subtypes were already expressed at the larval stage, with a similar tissue distribution pattern to that found in adults. For all stages, PPARalpha and PPARgamma were expressed at higher levels than PPARbeta, and PPARbeta immunolabeling was stronger in juveniles than in larval or adult stages. The percentages of hepatocyte nuclei immunolabeled for PPARs was higher in early developmental stages than in adults, similarly to AOX activity and V(VP). In conclusion, our results indicate that PPAR expression, the activity of its target gene AOX, and peroxisomal biogenesis are developmentally modulated in zebrafish.

[Fibrous hamartoma of the chest wall: apropos of a case]

Fibrous hamartoma of the child is one of the congenital fibromatosis. It is considered as an expansive, benign process, genuine of the settling site although changing in quantity, disposition and differentiation. The thoracic localization is very seldom found. Authors comment the most important features referring to this tumour.