Forearc carbon sink reduces long-term volatile recycling into the mantle.

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Development of a new integrative toxicity index based on an improvement of the sea urchin embryo toxicity test.

The sea urchin embryo toxicity test is classically used to assess the noxious effects of contaminated marine waters and sediments. In Italian guidelines on quality of dredged sediments, the standard toxicity criteria used for this assay are based on a single endpoint at 48 hours of development, corresponding to the pluteus stage. Different typologies of abnormalities, including those which occur at earlier stages, are not categorized, thus preventing the evaluation of the actual teratogenic hazards. A new integrative toxicity index has been developed in this study based on the analysis of two developmental stages, at 24 and 48h post-fertilization, and the differentiation between development delays and germ layers impairments: the new toxicity index is calculated by integrating the frequency of abnormal embryos with the severity of such abnormalities. When tested on dredged sediments, the evaluation of increasing levels of toxicity affecting embryonic outcomes enhanced the capability to discriminate different samples, appearing particularly relevant to validate the sea urchin embryo toxicity assay, and supporting its utility in practical applications such as the sediments classification in harbor areas.

Effects of harmful dinoflagellate Ostreopsis cf. ovata exposure on immunological, histological and oxidative responses of mussels Mytilus galloprovincialis.

In the last decade massive blooms of the Ostreopsis cf. ovata have occurred in the Mediterranean basin, posing great concern to both environmental and human health. Biotoxicological and chemical studies demonstrated that O. cf. ovata produces palytoxin and ovatoxins; besides direct respiratory effects on humans due to inhalation of marine toxic aerosols, O. cf. ovata blooms can cause adverse effects on benthic invertebrates. The main aim of this study was to highlight the role of immunological, cellular and oxidative mechanisms in modulating the toxicity induced by O. cf. ovata in mussels Mytilus galloprovincialis. Organisms were exposed in laboratory condition to O. cf. ovata and analysed after 7 and 14 days of exposure. Obtained results demonstrated a clear involvement of the immune system with a significant decrement of granulocytes respect to the hyalinocytes type cells, a diminished phagocytosis activity and a reduced lysosomal membrane stability in haemocytes, after both 7 and 14 days of exposure. Histological analyses showed a decrease of the digestive gland wall thickness, dilatation of the tubules, haemocytes infiltration into the digestive gland and a decrement of neutral lipid levels in exposed mussels; similar results suggest a possible inhibition of the feeding activity, with a consequent induction of authophagic phenomena and utilization of stored reserve products such as neutral lipids. Antioxidant parameters revealed a limited role of O. cf. ovata to induce oxidative stress in mussels exposed under laboratory conditions excepting for a certain increase of catalase, glutathione reductase and glutathione peroxidases activities, and a significantly higher capability to neutralize peroxyl radicals in mussels exposed for 14 days. Although the obtained results suggest a non-specific response of mussels to the O. cf. ovata exposure, observed effects on the general health status of exposed mussels should be adequately considered when assessing the ecological relevance of these algal blooms.

Alterations of ROS pathways in scleroderma begin at stem cell level.

Scleroderma is a chronic systemic autoimmune disease (primarily of the skin) characterized by fibrosis (or hardening), vascular alterations and autoantibodies production.There are currently no effective therapies against this devastating and often lethal disorder. Despite the interest for the immunomodulatory effects of mesenchymal stem cells (MSCs) in autoimmune diseases, the role of MSCs in scleroderma is still unknown. A pivotal role in scleroderma onset is played by oxidative stress associated with the accumulation of great amounts of reactive oxygen species (ROS). This study depicts some phenotypic and functional features of MSCs isolated from the skin of healthy and scleroderma patients; the ROS production and accumulation, the expression of ERK1/2 and the effects of the stimulation with PDGF, were analyzed in MSCs; results were compared to those observed in primary fibroblasts (Fbs) isolated from the same subjects. We found that the pro-oxidant environment exerted by scleroderma affects MSCs, which are still able to counteract the ROS accumulation by improving the antioxidant defenses. On the contrary, scleroderma fibroblasts show a disruption of these mechanisms, with consequent ROS increase and the activation of the cascade triggered by scleroderma auto-antibodies against PDGFR.

Polystyrene nanoplastics in the marine mussel Mytilus galloprovincialis.

Concerns about plastic pollution and its toxicity towards animals and people are growing. Polystyrene (PS) is a plastic polymer highly produced in Europe for packaging purposes and building insulation amongst others. Whatever their source-illegal dumping, improper waste management, or a lack of treatment for the removal of plastic debris from wastewater treatment plants-PS products ultimately end up in the marine environment. Nanoplastics (<1000 nm) are the new focus for plastic pollution, gaining broad interest. Whether primary or secondary, their small size permits nanoparticles to cross cellular boundaries, consequently leading to adverse toxic effects. An in vitro assay of Mytilus galloprovincialis haemocytes exposed to 10 µg/L of polystyrene nanoplastics (PS-NPs; 50 nm) for 24 h was used to test cellular viability along with the luminescence inhibition (LC50) of Aliivibrio fischeri bacteria to evaluate acute toxicity. Cellular viability of mussel haemocytes decreased significantly after a 24 h exposure and PS-NPs LC50 range from 180 to 217, µg/L. In addition, a 28-day exposure of the marine bivalve M. galloprovincialis to PS-NPs (10 µg/L; 50 nm) was performed to evaluate the neurotoxic effects and the uptake of these plastic particles in three bivalve tissues (gills, digestive gland, and gonads). The ingestion of PS-NPs was time- and tissue-specific, suggesting that PS-NPs are ingested through the gills and then translocated through the mussel bloodstream, to the digestive gland and gonads where the highest amount of ingested PS-NPs was reported. Ingested PS-NPs may compromise the digestive glands' key metabolic function and impair mussels' gametogenic and reproductive success. Data on acetylcholinesterase inhibition and those previously obtained on a wide range of cellular biomarkers were elaborated through weighted criteria providing a synthetic assessment of cellular hazard from PS-NPs.

Effect of biologic therapies targeting tumour necrosis factor-α on cutaneous mesenchymal stem cells in psoriasis.

BACKGROUND: Psoriasis is a Th1 immune-mediated, inflammatory disease, in which skin lesions appear many years before the related metabolic and cardiovascular comorbidities, according to the theory of the 'psoriatic march'. Inducible nitric oxide synthetase (iNOS), tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) are directly implicated in determining both skin lesions and systemic involvement in psoriasis. Reactive oxygen species actively promote the secretion of inflammatory Th1 cytokines directly involved in the pathogenesis of psoriasis. OBJECTIVES: Evaluation of VEGF expression and production, nitric oxide (NO) production, iNOS expression, and the antioxidant response of mesenchymal stem cells (MSCs), both before and after 12 weeks of treatment with the TNF-α inhibitors adalimumab or etanercept. METHODS: Biochemical, morphological and immunohistochemical analyses were performed in MSCs isolated from nonlesional, perilesional and lesional skin of patients with psoriasis, before and after treatment. RESULTS: The treatments were able to reduce the expression and production of VEGF, the expression of iNOS and the production of NO in MSCs of patients with psoriasis. TNF-α inhibitors also reduced the oxidative damage in MSC membrane and proteins, several antioxidant systems responded to treatments with a general inhibition of activities (glutathione S-transferase and catalase) and these effects were also supported by a general decrease of total oxyradical scavenging capacity towards hydroxyl radicals and peroxynitrite. CONCLUSIONS: TNF-α inhibitors are able to change the physiopathological pathway of psoriasis, and our results suggest their therapeutic effects already take place at the level of MSCs, which probably represent the cells primarily involved in the 'psoriatic march'.

Do microplastic contaminated seafood consumption pose a potential risk to human health?

Microplastics are present in all parts of the ocean and can have deleterious effects on marine resources. The aim of this work was to map the presence of microplastics in commercial marine species such as bivalves (mussels Mytilus galloprovincialis and clams Scrobicularia plana), crabs (Carcinus maenas) as well as fish (Mullus surmuletus) to relate microplastics levels to pollution sources, assess possible impact on marine food chains and on human health. These species were collected from several sites of the Ria Formosa lagoon and along the south coast of Portugal. A quantitative assessment (number, size and color) and typology of microplastics were made in these species. Only one green fragment of polypropylene was detected in the gills of the crabs, while a blue polyethylene fragment was detected in the hepatopancreas of the mullets. Moreover, no microplastics were present in S. plana nor in the crabs whole soft tissues. Among mussels, 86% of microplastics were present from all sites and the number, size and color were site specific. Mussels from the west side of the coast (Sites 1-3) had the highest levels of MPs per mussel and per weight compared to the other sites, probably related to the impact of touristic activity, fishing gears, fresh water and sewage effluents along with the hydrodynamics of the area.

Assessing the efficiency and eco-sustainability of bioremediation strategies for the reclamation of highly contaminated marine sediments.

Coastal sediments subjected to high anthropogenic impacts can accumulate large amounts of polycyclic aromatic hydrocarbons (PAHs) and metals, demanding effective and eco-sustainable remediation solutions. In this study, we carried out bioremediation experiments on marine sediments highly contaminated with PAHs and metals. In particular, we investigated the effects of biostimulation (by the addition of inorganic nutrients), bioaugmentation (by the addition of fungi belonging to Aspergillus sp.) and microbial fuel cell-based strategies on PAH degradation and on changes in metal partitioning. Results reported here indicate that all biotreatments determined a significant decrease of PAH concentrations (at least 60%) in a relatively short time interval (few weeks) and that biostimulation was the most effective approach (>90%). Biostimulation determined a faster degradation rate of high than low molecular weight PAHs, indicating a preferential biodegradation of specific PAH congeners. At the same time, the biotreatments changed the partitioning of metals, including their solubilization, suggesting the need of parallel environmental risk assessment. Our findings also suggest that ex situ biotreatments can have a lower carbon footprint than current management options of contaminated sediments (i.e., landfill disposal and/or disposal in confined aquatic facilities), but integration with other strategies for metal removal (e.g. through bioleaching) from sediments is needed for their safe re-use. Overall, results presented here provide new insights into the development of effective and eco-sustainable bioremediation strategies for the reclamation of highly contaminated marine sediments.

Cellular responses in the cyprinid Leuciscus cephalus from a contaminated freshwater ecosystem.

The response of wild chubs (Leuciscus cephalus) to chemical pollution was assessed in a metal contaminated river (Cecina River, Italy) through a wide battery of biomarkers which included: Comet assay detecting DNA strand breaks; diffusion assay for apoptosis induction; micronucleus test assessing chromosomal alterations; ethoxyresorufin O-deethylase (EROD) activity for the induction of cytochrome P 4501A; acetylcholinesterase (AChE) activity responsive to pesticide exposure; vitellogenin gene expression in males revealing estrogenic effects. Bioaccumulation of mercury, chromium and polycyclic aromatic hydrocarbons (PAHs) was also determined. Levels of mercury and PAHs were higher in tissues of chubs sampled from the most downstream station, reflecting an anthropogenic pollution of industrial origin. Otherwise, accumulation of Cr was quite similar in fish along the entire course of Cecina River confirming a natural origin due to local geochemical features. Biomarker responses revealed a significant increase of apoptotic cells, DNA stand breaks and micronucleus frequency in chubs from the more impacted sites. A slight EROD induction and AChE inhibition were only seen at the most downstream station demonstrating a limited impact due to PAHs and pesticides. On the other hand, the induction of vitellogenin gene in male chubs was measured in all the sites, suggesting a diffuse estrogenic effect. This study confirmed the utility of large batteries of biomarkers in biomonitoring studies and the suitability of wild chub as bioindicator organism for river basins.

Long-term exposure of Mytilus galloprovincialis to diclofenac, Ibuprofen and Ketoprofen: Insights into bioavailability, biomarkers and transcriptomic changes.

Non-steroidal anti-inflammatory drugs (NSAIDs) represent a growing concern for marine ecosystems due to their ubiquitous occurrence and documented adverse effects on non-target organisms. Despite the remarkable efforts to elucidate bioaccumulation and ecotoxicological potential under short-term conditions, limited and fragmentary information is available for chronic exposures. In this study bioavailability, molecular and cellular effects of diclofenac (DIC), ibuprofen (IBU) and ketoprofen (KET) were investigated in mussels Mytilus galloprovincialis exposed to the realistic environmental concentration of 2.5 µg/L for up to 60 days. Results indicated a significant accumulation of DIC and IBU but without a clear time-dependent trend; on the other hand, KET concentrations were always below the detection limit. Analyses of a large panel of molecular, biochemical and cellular biomarkers highlighted that all investigated NSAIDs caused alterations of immunological parameters, genotoxic effects, modulation of lipid metabolism and changes in cellular turn-over. This study provided the evidence of long-term ecotoxicological potential of NSAIDs, further unraveling the possible hazard for wild marine organisms.

Effects of blood lipid lowering pharmaceuticals (bezafibrate and gemfibrozil) on immune and digestive gland functions of the bivalve mollusc, Mytilus galloprovincialis.

Fibrates are hypolipidemic pharmaceuticals that have been detected as contaminants in wastewaters and surface waters. In this work, the possible effects of two fibrates, Bezafibrate (BEZA) and Gemfibrozil (GEM) in the bivalve mollusc Mytilus spp were investigated. In the immune cells, the hemocytes, addition of both compounds in vitro induced rapid lysosomal membrane destabilization, extracellular lysozyme release, NO production and decreased phagocytic activity. The effect of fibrates were partly mediated by activation of ERK and p38 MAPKs (Mitogen Activated Protein Kinases), as demonstrated by the use of specific inhibitors of different kinases. The effects of fibrates on hemocyte function were confirmed in vivo, in the hemocytes of mussels injected with 0.01, 0.1 and 1 nmol/animal (corresponding to nominal concentrations of 3.61, 36.18 and 361.8ng/g dry weight for BEZA and of 2.50, 25.03 and 250.35 ng/g dry weight for GEM, respectively) and sampled at 24h post-injection. Both compounds induced a concentration-dependent lysosomal destabilization and extracellular lysozyme release; an increase in phagocytosis was observed at the highest concentration. In vivo exposure to fibrates also induced significant effects on mussel digestive gland, the key metabolic organ in bivalves. Both BEZA and GEM increased the activity of the glycolytic enzymes phosphofructokinase (PFK) and pyruvate kinase (PK), and of Glutathione transferase (GST) glutathione reductase (GSR), and total glutathione content. A significant increase in the peroxisomal enzyme catalase was observed; however, BEZA exposure decreased Palmytoyl CoA oxidase activity, whereas GEM was ineffective. The results indicate that in mussels environmental concentrations of hypolipidemic drugs can affect the immune function, as well as glycolysis, redox balance and peroxisomal function.

An in vitro study on the free radical scavenging capacity of ergothioneine: comparison with reduced glutathione, uric acid and trolox.

BACKGROUND: Treatment of oxidative stress-related pathologies is a possible therapeutical strategy for the future. Natural product with antioxidant properties could trigger this goal. The aim of this in vitro study was to assess the antioxidant activity of the natural product ergothioneine (EGT), a compound of plant origin, which is assimilated and conserved by mammals in erythrocytes, kidney, seminal fluid and liver. METHODS: We measured the antioxidant activity of EGT as its ability to antagonize the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) by hydroxyl radical, peroxyl radicals and peroxynitrite. The results are expressed as total oxyradical scavenging capacity (TOSC) units. Glutathione (GSH), uric acid and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), the water-soluble analog of vitamin E, were used as the reference antioxidants. RESULTS: EGT was the most active scavenger of free radicals as compared to classic antioxidants as GSH, uric acid and trolox. In particular, the highest antioxidant capacity exhibited by EGT vs. peroxyl radicals (5.53 +/- 1.27 units) resulted 25% higher than the value obtained with the reference antioxidant trolox (4.4 +/- 0.6 units, P < 0.01). The scavenging capacity of EGT towards hydroxyl radicals (0.34 +/- 0.09 units) was 60% higher, as compared to uric acid (0.21 +/- 0.04 units, P < 0.001), which represent the reference antioxidant vs. hydroxyl radicals. Finally, EGT showed the highest antioxidant activity also towards peroxynitrite (5.2 +/- 1.0 units), with a scavenging capacity 10% higher than that of uric acid (4.7 +/- 0.9 units, P < 0.05). CONCLUSIONS: This study showed that EGT has potent intrinsic anti-hydroxyl, anti-peroxyl and anti-peroxynitrite radicals antioxidant activity, as compared to classic molecules with antioxidant capacity as GSH, trolox and uric acid. This appears of interest, given the increasing use of non-vitamins cocktails for therapeutical approaches to many oxidative-induced pathologies.

Cellular biomarkers for monitoring estuarine environments: transplanted versus native mussels.

In developed countries, estuarine environments are often subjected to chemical pollution, whose biological impact is profitably evaluated by the use of multi-biomarker approaches on sentinel species. In this paper, we investigate genotoxicity and lysosomal alterations in the Mediterranean mussel (Mytilus galloprovincialis), from the estuary of the River Cecina (Tuscany, Italy), selected as "pilot basin" within the Water Frame Directive (2000/60 European Community). Both native and 1 month transplanted mussels were used in order to compare these two approaches in terms of sensitiveness of specific biomarker responses. Genotoxic effects were evaluated as strand breaks, by single cell gel electrophoresis (or Comet assay), and as chromosomal alterations, by the micronucleus test in gill cells. Lysosomal alterations were assessed by the neutral red retention time (in haemocytes), lipofuscin accumulation and ultrastructure (in digestive cells). Heavy metal bioaccumulation was also analysed. Mussels from the River Cecina showed a general alteration of all the biomarkers investigated, accompanied by an elevation of tissue metal levels. However, some differences in specific responses occurred between transplanted and native mussels. Early biomarkers, such as those based on DNA and lysosomal membrane integrity, were induced at similar degree in native and transplanted mussels; while alterations resulting from cumulative events, as the increase of micronuclei frequency were much more elevated in native specimens (23.1+/-7.6) than in transplanted (9.3+/-4.7) and reference ones (5.8+/-5.2). Similarly, the comparison between lipofuscin accumulation and mean lysosomal diameter in impacted and control sites, gave significant differences exclusively with transplanted mussels. These results suggest that the parallel use of caged and native mussels in environmental biomonitoring can improve the characterization of the study area.

Arsenic speciation and susceptibility to oxidative stress in the fanworm Sabella spallanzanii (Gmelin) (Annelida, Sabellidae) under naturally acidified conditions: An in situ transplant experiment in a Mediterranean CO2 vent system.

The fanworm Sabella spallanzanii (Gmelin, 1791) (Annelida, Sabellidae) is considered tolerant to several types of stressors but is generally absent from the CO2 vents. A peculiar characteristic of this species is the elevated content of arsenic in the gills, particularly dimethylarsinic acid (DMA), stored as an anti-predatory compound. In this study, modulation of trace metal levels, chemical speciation of arsenic and oxidative stress biomarkers were quantified in S. spallanzanii after a 30days transplant experiment into naturally acidified conditions in a Mediterranean vent system. No significant bioaccumulation of metals was observed in the thoracic tissues and branchial crowns after the translocation period, whereas variations occurred in the relative abundance of different arsenic compounds with the appearance of inorganic forms. The antioxidant system of translocated polychaetes exhibited a significant decrease of enzymatic activities of both catalase and glutathione peroxidases, and the impairment of the overall capability to neutralize hydroxyl radicals (OH). This highlighted an oxidative challenge primarily on the detoxification pathway of hydrogen peroxide. Overall low pH-elevated pCO2 may have detrimental effects on arsenic metabolism and oxidative status of S. spallanzanii, supporting the hypothesis of species-specific differences in vulnerability to ocean acidification.

Transcriptional and cellular effects of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in experimentally exposed mussels, Mytilus galloprovincialis.

The aim of the present investigation was to provide new insights on accumulation and possible adverse effects of various non-steroidal anti-inflammatory drugs (NSAIDs) in mussels, Mytilus galloprovincialis, exposed to an environmentally realistic concentration (0.5µg/L) of individual compounds, Acetaminophen (AMP), Diclofenac (DIC), Ibuprofen (IBU), Ketoprofen (KET) or Nimesulide (NIM). The measurement of drugs in mussel tissues was integrated with both functional alterations at cellular level and transcriptomic responses. Results indicated the capability of mussels to accumulate DIC and NIM, while AMP, IBU and KET were always below detection limit. A large panel of ecotoxicological biomarkers revealed the early onset of alterations induced by tested NSAIDs on immunological responses, lipid metabolism and DNA integrity. The gene transcription analysis through DNA microarrays, supported cellular biomarker results, with clear modulation of a large number of genes involved in the arachidonic acid and lipid metabolism, immune responses, cell cycle and DNA repair. The overall results indicated an ecotoxicological concern for pharmaceuticals in M. galloprovincialis, with transcriptional responses appearing as sensitive exposure biomarkers at low levels of exposure: such changes, however, are not always paralleled by corresponding functional effects, suggesting caution when interpreting observed effects in terms of perturbed cellular pathways. Fascinating similarities can also be proposed in the mode of action of NSAIDs between bivalves and vertebrate species.

Ecotoxicological potential of non-steroidal anti-inflammatory drugs (NSAIDs) in marine organisms: Bioavailability, biomarkers and natural occurrence in Mytilus galloprovincialis.

Pharmaceuticals represent a major environmental concern since the knowledge on their occurrence, distribution and ecotoxicological potential is still limited particularly in coastal areas. In this study, bioaccumulation and cellular effects of various non steroidal anti-inflammatory drugs (NSAIDs) were investigated in mussels Mytilus galloprovincialis to reveal whether common molecules belonging to the same therapeutic class might cause different effects on non target organisms. Organisms exposed to environmental concentrations of acetaminophen (AMP), diclofenac (DIC), ibuprofen (IBU), ketoprofen (KET) and nimesulide (NIM) revealed a significant accumulation of DIC, IBU and NIM, while AMP and KET were always below detection limit. Nonetheless, for all tested NSAIDs, measurement of a large panel of ecotoxicological biomarkers highlighted impairment of immunological parameters, onset of genotoxicity and modulation of lipid metabolism, oxidative and neurotoxic effects. Laboratory results were integrated with a field study which provided the first evidence on the occurrence of DIC, IBU and NIM in tissues of wild mussels sampled during summer months from an unpolluted, touristic area of Central Adriatic Sea. Overall results demonstrated M. galloprovincialis as a good sentinel species for monitoring presence and ecotoxicological hazard of pharmaceuticals in the Mediterranean.

Antioxidant and oxidative stress related responses in the Mediterranean land snail Cantareus apertus exposed to the carbamate pesticide Carbaryl.

The aim of the present work was to study the alterations of the antioxidant defenses and the overall susceptibility to oxidative stress of the terrestrial snail Cantareus apertus exposed to the carbamate pesticide Carbaryl at a low environmentally realistic concentration. The animals were exposed to Lactuca sativa soaked for 1h in 1µM Carbaryl. The temporal dynamics of the responses was assessed by measurements at 3, 7 and 14days of exposure. C. apertus exposed to Carbaryl activates a number of enzymatic antioxidant responses, represented by the early induction of catalase, glutathione peroxidase, glutathione reductase, followed by a delayed induction of superoxide dismutase. Concomitantly, a derangement of the total oxyradical scavenging of the tissues was observed, suggesting an overall impairment of the tissue capability to neutralize ROS probably resulting from the overall negative balance between enzymatic antioxidant defense capability and oxidative stress intensity. This negative balance exposed the animals to the risk of oxidative stress damages including genotoxic damage. Compared to acetylcholinesterase inhibition, the antioxidant responses developed to Carbaryl exposure at the low concentration utilized showed a greater percentage variation in exposed organisms. The results pointed out the high sensitivity of the antioxidant and oxidative stress related responses to Carbaryl exposure at an environmental realistic concentration, demonstrating their usefulness in environmental monitoring and risk assessment. The study highlights also the usefulness of the terrestrial snail C. apertus as potential bioindicator species for assessing the risk of pesticide environmental contamination.

Antioxidant capacity of polychaetes occurring at a natural CO2 vent system: Results of an in situ reciprocal transplant experiment.

Ocean acidification (OA) is occurring at a fast rate, resulting in changes of carbonate chemistry in the oceans and in lowering of the pH. Previous studies have documented significant changes in the antioxidant defenses of marine species in response to OA. Here, selected polychaete species, Platynereis dumerilii, Polyophthalmus pictus and Syllis prolifera, were sampled from a natural CO2 vent system (pH = 7.3) and from a non-venting 'control' site (pH = 8.1), and reciprocally transplanted in these areas for 30 days. Total antioxidant capacity toward different forms of oxyradicals was compared in native and transplanted polychaetes: the aim was to assess whether the environmental conditions at the vent site would act as a prooxidant stressor, and the capability of polychaetes to modulate their antioxidant capacity to counteract a varied oxyradicals formation. None of the investigated species enhanced the antioxidant potential during the experiment. A significant reduction of the capability to neutralize different forms of oxyradicals was observed in P. pictus and, partially, in S. prolifera when transplanted from control to naturally-acidified conditions. On the other hand, populations of P. dumerilii originating from the vent and of S. prolifera from both control and acidified sites, showed higher constitutive antioxidant efficiency toward peroxyl radicals and peroxynitrite, which may allow them to cope with short-term and chronic exposure to higher oxidative pressure without further enhancement of antioxidant defenses. Since low pH - high pCO2 is the greatest environmental difference between the control and the vent sites, we suggest that the pro-oxidant challenge due to such peculiarities may have different biological consequences in different polychaete species. Some appear more susceptible to oxidative effects, while others acquire a long term acclimatization to vent conditions through the enhancement of their basal antioxidant protection.