Percorrer por autor "Bebianno, Maria João"
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- 2-D difference gel electrophoresis approach to assess protein expression profiles in Bathymodiolus azoricus from Mid-Atlantic Ridge hydrothermal ventsPublication . Company, Rui; Antúnez, Oreto; Bebianno, Maria João; Cajaraville, Miren P.; Torreblanca, AmparoHydrothermal vent mussels Bathymodiolus azoricus are naturally exposed to toxic chemical species originated directly from vent chimneys. The amount of toxic elements varies significantly among vent sites along the Mid-Atlantic Ridge and B. azoricus must be able to adapt to changes in hydrothermal fluid composition, temperature and pressure. The aim of this work was to study changes in the proteome in the "gill-bacteria complex" of mussels B. azoricus from three hydrothermal vent sites with distinct environmental characteristics using 2-D Fluorescence Difference Gel Electrophoresis (2-D DIGE). Results showed that 31 proteins had different expression profiles among vent sites and both cluster and principal component analysis confirm a clear separation of mussels between sites. This suggests the existence of specific parameters grouping individuals from the same hydrothermal site. Protein spots of the more abundant differentially expressed proteins were excised, digested with trypsin and identified by mass spectrometry. All identified proteins (actin, ubiquinone, S-adenosylhomocysteine hydrolase, cysteine peptidases, chaperonin and catalase) have been related previously with oxidative stress conditions and are known to be affected by ROS inducing stressors, including metals. Results point out to specific adaptations at the proteome level of B. azoricus depending on the level of toxicants present in their environment.
- A mussel watch in the Ria Formosa lagoonPublication . Morgado, M. E.; Bebianno, Maria JoãoThe present work analyzes the concentrations of various metals (Ag, Cd, Cr, Cu, Ni, Pb and Zn) in the edible part of the mussel Mytilus galloprovincialis from the Ria Formosa lagoon (Portugal). Mussels of a similar size (5-7 cm) were collected. The results indicate that the dispersion and accumulation of metals in mussels is influenced essentially by the sources of pollution and the bioavailability of the metal. The highest concentrations of Ag, Cu and Ni occurred in the mussels from sites 1, 6 and 7, which are mainly related to inputs from urban discharges. The highest concentrations of Cr were found in the mussels from sites 2 and 5, located near urban discharges and metallic structures. The highest concentrations of Pb were recorded in the mussels from site 9, associated with fuel from boats and diffuse inputs of this metal. The mussels at sites 3, 4 and 9 presented the highest concentrations of Zn and Cd, probably caused by physical and chemical processes that occur in the boundary between the lagoon and the ocean. The concentrations of Ag and Ni in the mussels of Ria Formosa are relatively low when compared to other geographical locations. The concentrations of Cd, Cr, Cu and Pb accumulated in the mussels reveal low contamination. As for the concentration of Zn, the values in the Ria Formosa mussels are higher in the eastern part of the lagoon than in the western part, revealing signs of contamination by this metal.
- Accumulation and toxicity of copper oxide nanoparticles in the digestive gland of Mytilus galloprovincialisPublication . Gomes, Tânia; Pereira, Catarina Guerreiro; Cardoso, Cátia; Pinheiro, José Paulo; Cancio, I.; Bebianno, Maria JoãoGiven the wide use of CuO nanoparticles in various industrial and commercial applications they will inevitably end up in the aquatic environment. However, little information exists on their biological effects in bivalve species. Accordingly, mussels Mytilus galloprovincialis were exposed to 10 g Cu L−1 as CuO nanoparticles and Cu2+ for 15 days, and biomarkers of oxidative stress (superoxide dismutase, catalase and glutathione peroxidase), damage (lipid peroxidation) and metal exposure (metallothionein) were determined along with Cu accumulation in the digestive glands of mussels. Cu was linearly accumulated with time of exposure in mussels exposed to CuO nanoparticles, while in those exposed to Cu2+ elimination was significant by day 15. Both forms of Cu cause oxidative stress with distinct modes of action. Exposure to CuO nanoparticles induces lower SOD activity in digestive glands compared to those exposed to Cu2+, while CAT was only activated after 7 days of exposure to nano and ionic Cu, with contradictory effects after 15 days of exposure and GPX activities were similar. Lipid peroxidation levels increased in both Cu forms despite different antioxidant efficiency. Moreover, a linear induction of metallothionein was detected with time in mussels exposed to CuO nanoparticles, directly related to Cu accumulation, whereas in those exposed to Cu2+ metallothionein was only induced after 15 days of exposure. Since only a small fraction of soluble Cu fraction was released from CuO nanoparticles, the observed effects seem to be related to the nano form of Cu, with aggregation as a key factor. Overall, our results show that the digestive gland is susceptible to CuO nanoparticles related oxidative stress, and is also the main tissue for their accumulation.
- Adaptation of the antioxidant defence system in hydrothermal-vent mussels (Bathymodiolus azoricus) transplanted between two Mid-Atlantic Ridge sitesPublication . Company, Rui; Serafim, Angela; Cosson, Richard; Fiala-Medioni, Aline; Dixon, David R.; Bebianno, Maria JoãoThe vent mussel Bathymodiolus azoricus is the dominant member of the Northern Mid-Atlantic Ridge (MAR) hydrothermal megafauna, and lives in an environment characterized by temporal and spatial variations in the levels of heavy metals, methane and hydrogen sulphide, substances which are known to increase reactive oxygen species levels in the tissues of exposed organisms. To evaluate the effects of two contrasting hydrothermal environments on the antioxidant defence system of this vent mussel species, a 2-week transplant experiment was carried out involving mussels collected from the relatively deep (2300 m), and chemical rich, Rainbow vent field. These were transplanted to the shallower (1700 m), and relatively less toxic, Lucky Strike vent field. To achieve this objective, levels of superoxide dismutase, catalase (CAT), total glutathione peroxidase (GPx), selenium-dependent glutathione peroxidase and lipid peroxidation (LPO) were measured in the gills and mantle tissues of resident and transplant mussels before and after the transplant experiment. With the exception of CAT, the gills of the transplanted mussels had significantly higher antioxidant enzyme activity compared with the basal levels in the donor (Rainbow) and recipient (Lucky Strike) populations; whereas the antioxidant enzyme levels in the mantle tissues of the transplants reflected the baseline levels of activity in the native Lucky Strike mussels after 2 weeks. In contrast, LPO levels were significantly higher in both tissue types in the transplants than in either the source or the recipient populations, which suggested a response to hydrostatic pressure change (note, the transplant animals were brought to the surface for transportation between the two vent fields). The fact that the Rainbow mussels survived the transplant experience indicates that B. azoricus has a very robust constitution, which enables it to cope behaviourally, physiologically and genetically with the extreme conditions found in its naturally contaminated deep-sea environment.
- Adaptation to metal toxicity: a comparison of hydrothermal vent and coastal shrimpsPublication . Gonzalez-Rey, Maria; Serafim, Angela; Company, Rui; Bebianno, Maria JoãoRainbow vent field is one of the most metal-contaminated hydrothermal sites on the Mid-Atlantic Ridge near the Azores region. Two hydrothermal shrimp species dominate the fauna at the Rainbow site along with the mussel Bathymodiolus azoricus. Although the levels of essential and non-essential metals in these shrimps have been studied, the biological consequences of a metal-rich environment are still largely unknown. Therefore, the aim of this study was to determine the levels of metal-binding proteins - metallothioneins (MT) and the activities of antioxidant enzymes - superoxide dismutase, catalase, total glutathione peroxidase and selenium-dependent glutathione peroxidase in two hydrothermal vent shrimps (Mirocaris fortunata and Rimicaris exoculata) collected from the Rainbow site and to compare them with two coastal shrimps (Palaemon elegans and Palaemonetes varians) from a south Portugal lagoon (Ria Formosa) to evaluate their different adaptation strategies towards metals in their environment. Results show significant differences in MT levels and antioxidant enzymatic activities between vent and coastal shrimps and also between shrimp species collected from the same site. This suggests that biochemical responses in both vent and coastal shrimps are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently confer successful adaptation for survival in a metal-extreme environment.
- Analysis of proteins from marine molluscsPublication . Chora, Suze; Bebianno, Maria João; Roméo, MichèleApplication of the two-dimensional gel electrophoresis (2DE) protocols which were developed for samples of mammalian origin gives unsatisfactory results when used in samples from marine molluscs. This chapter describes a detailed protocol of 2DE that can be applied to these organisms, especially for Ruditapes decussatus and Bathymodiolus azoricus.
- Antioxidant and lipid peroxidation responses in Mytilus galloprovincialis exposed to mixtures of benzo(a)pyrene and copperPublication . Maria, Vera L.; Bebianno, Maria JoãoThis study aimed to assess the antioxidant system potential and lipid peroxidative effects, in the gill and digestive gland of Mytilus galloprovincialis exposed to individual and binary mixtures of benzo(a)pyrene (BaP) and Cu for 7 days. Data demonstrated that in mussels exposed to BaP antioxidant enzymes (catalase--CAT, total glutathione peroxidase--tGPx, glutathione S-transferase--GST and glutathione reductase--GR) and lipid peroxidation (LPO) increased in the gill. On the contrary, in the digestive gland inhibitory antioxidant effects (superoxide dismutase-SOD, GR, metallothioneins-MT) and no changes in LPO levels were detected. Cu was also a potent oxidant agent since MT and LPO levels increased in mussel gill, despite no LPO effect in the digestive gland. For both single contaminants the organ specificity and distinct physiologic/metabolism roles were evident in terms of antioxidant capacity. Gill SOD inhibition, MT and GST unchanged was a result of "simple independent action" of exposure to BaP and Cu. "Interactions" in the binary mixtures, led to absence of changes in LPO effects. In the digestive gland, BaP and Cu interactions were also responsible for the GST and LPO enhancement (antagonistic effects). The current findings demonstrate the differences in antioxidant responses where the organ dependency highlights each contaminant particular mode of action. Generally, in the gill "non-interactive" effects occurred with the lowest Cu concentration while "interactions" exist for the mixture with the highest Cu concentrations. In the digestive gland, "interactions" and "no interaction" effects occurred in all the binary mixtures. Complex contaminant mixtures interact differently based on target tissue which may lead to an imbalance in the mussels health status.
- Antioxidant biochemical responses to long-term copper exposure in Bathymodiolus azoricus from Menez-Gwen hydrothermal ventPublication . Company, Rui; Serafim, Angela; Cosson, Richard P.; Fiala-Médioni, Aline; Camus, Lionel; Colaço, Ana; Serrão-Santos, Ricardo; Bebianno, Maria JoãoCopper (Cu) is essential to various physiological processes in marine organisms. However, at high concentrations this redox-active transition metal may enhance the formation of reactive oxygen species (ROS) and subsequently initiate oxidative damage. High concentrations of Cu may increase oxidative damage to lipids, proteins and DNA. Bathymodiolus azoricus is a Mytilid bivalve very common in hydrothermal environments near the Azores Triple Junction continuously exposed to high metal concentrations, including Cu, emanating from the vent fluids. The knowledge of antioxidant defence system and other stress related biomarkers in these organisms is still scarce. The aim of this work was to study the effect of Cu (25 microg l(-1); 24 days exposure; 6 days depuration) on the antioxidant stress biomarkers in the gills and mantle of B. azoricus. The expression of stress related biomarkers was tissue-dependent and results suggest that other factors than metal exposure may influence stress biomarkers, since little variation in antioxidant enzymes activities, MT concentrations, LPO and total oxyradical scavenging capacity (TOSC) occurred in both control and Cu-exposed mussels. Moreover, there is a general tendency for these parameters to increase with time, in both control and Cu-exposed mussels, suggesting that reactive oxygen species (ROS) formation is not metal dependent, and may be related with poor physiological conditions of the animals after long periods in adverse conditions compared to those in hydrothermal environments.
- Antioxidant systems and lipid peroxidation in from Mid-Atlantic Ridge hydrothermal vent fieldsPublication . Bebianno, Maria João; Company, Rui; Serafim, Angela; Camus, L.; Cosson, R.; Fialamedoni, A.Enzymatic defenses involved in protection from oxygen radical damage were determined in gills and mantle of Bathymodiolus azoricus collected from three contrasting Mid-Atlantic Ridge (MAR) hydrothermal vent fields (Menez-Gwen, Lucky Strike and Rainbow). The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx) (total and Se-dependent), and levels of total oxyradical scavenging capacity (TOSC), metallothioneins (MT) and lipid peroxidation (LPO) were determined in B. azoricus tissues and the impact of metal concentrations on these antioxidant systems and lipid peroxidation assessed. SOD, CAT, TOSC, MTs and LPO levels were higher in B. azoricus gills while glutathione peroxidases (total and Se-dependent) were higher in the mantle, and with the exception of CAT, were of the same order of magnitude as in other molluscs. TOSC levels from Menez-Gwen indicate that the vent environment at this site is less stressful and the formation of ROS in mussels is effectively counteracted by the antioxidant defense system. TOSC depletion indicates an elevated ROS production in molluscs at the other two vent sites. Cytosolic SOD, GPx and LPO were more relevant at Lucky Strike (Bairro Alto) where levels of essential (Cu and Zn) and toxic metals (Cd and Ag) were highest in the organisms. CAT activity and LPO were predominant at the Rainbow vent site, where an excess of Fe in mussel tissues and in vent fluids (the highest of all three vent sites) may have contributed to increased LPO. Therefore, three distinct pathways for antioxidant enzyme systems and LPO based on environmental metal speciation of MAR vent fields are proposed for Bathymodiolus gills. At Menez-Gwen, TOSC towards peroxyl and hydroxyl radicals and peroxynitrite are predominant, while at Lucky Strike cytosolic SOD activity and GPx are the main antioxidant mechanisms. Finally at Rainbow, catalase and lipid peroxidation are dominant, suggesting that resistance of mussels to metal toxicity at these vent fields decreases in the sequence Menez-Gwen > Lucky Strike and Rainbow.
- Are litter, plastic and microplastic quantities increasing in the ocean?Publication . Galgani, Francois; Brien, Aleke Stoefen-o; Weis, Judith; Ioakeimidis, Christos; Schuyler, Qamar; Makarenko, Iryna; Griffiths, Huw; Bondareff, Joan; Vethaak, Dick; Deidun, Alan; Sobral, Paula; Topouzelis, Konstantinos; Vlahos, Penny; Lana, Fernanda; Hassellov, Martin; Gerigny, Olivia; Arsonina, Bera; Ambulkar, Archis; Azzaro, Maurizio; Bebianno, Maria JoãoWhilst both plastic production and inputs at sea have increased since the 1950s, several modelling studies predict a further increase in the coming years in these respective quantities. We compiled scientific literature on trends in marine litter, consisting largely of plastic and microplastics in the ocean, understanding that monitoring programs or assessments for these aspects are varied, frequently focusing on limited components of the marine environment in different locations, and covering a wide spectrum of marine litter types, with limited standardization. Here we discuss how trends in the amounts of litter in the marine environment can be compared with the information provided by models. Increasing amounts of plastic are found in some regions, especially in remote areas, but many repeated surveys and monitoring efforts have failed to demonstrate any consistent real temporal trend. An observed steady state situation of plastic quantities in many marine compartments and the fate and transport of plastic in the marine environment remain areas for much needed further research.