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Registros recuperados: 6
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A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum ArchiMer
Long, Marc; Tallec, Kevin; Soudant, Philippe; Lambert, Christophe; Le Grand, Fabienne; Sarthou, Geraldine; Jolley, Dianne; Hegaret, Helene.
Harmful microalgal blooms are a threat to aquatic organisms, ecosystems and human health. Toxic dinoflagellates of the genus Alexandrium are known to produce paralytic shellfish toxins and to release bioactive extracellular compounds (BECs) with potent cytotoxic, hemolytic, ichtyotoxic and allelopathic activity. Negative allelochemical interactions refer to the chemicals that are released by the genus Alexandrium and that induce adverse effects on the physiology of co-occurring protists and predators. Releasing BECs gives the donor a competitive advantage that may help to form dense toxic blooms of phytoplankton. However BECs released by Alexandrium minutum are uncharacterized and it is impossible to quantify them using classical chemical methods....
Tipo: Text Palavras-chave: Harmful algal bloom; Alexandrium; Allelopathy; Cytotoxicity; PAM fluorometry; Bioassay.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00453/56424/58116.pdf
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Allelochemicals from Alexandrium minutum induce rapid inhibition of metabolism and modify the membranes from Chaetoceros muelleri ArchiMer
Long, Marc; Tallec, Kevin; Soudant, Philippe; Le Grand, Fabienne; Donval, Anne; Lambert, Christophe; Sarthou, Geraldine; Jolley, Dianne F.; Hegaret, Helene.
Allelochemical interactions are likely to be a contributing factor explaining the success of large blooms of the harmful marine dinoflagellate Alexandrium, however, the physiological mechanisms of allelochemical interactions remain poorly described. Here we investigated the sub-lethal effects (on an hourly scale) of a filtrate containing allelochemicals from Alexandrium minutum on the physiology of the common diatom Chaetoceros muelleri. The filtrate induced deleterious effects to the diatom physiology within only 30 min of exposure. Esterase activity and photosynthesis were drastically inhibited, with up to 34% of the population being metabolically inactive and up to 30% reduction in photosystem II quantum yield when exposed to the filtrate. In addition,...
Tipo: Text Palavras-chave: Allelopathy; Alexandrium; Metabolism; Photoinhibition; Lipids; Pigments.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00460/57133/59748.pdf
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Cellular responses of Pacific oyster ( Crassostrea gigas ) gametes exposed in vitro to polystyrene nanoparticles ArchiMer
Gonzalez-fernandez, Carmen; Tallec, Kevin; Le Goic, Nelly; Lambert, Christophe; Soudant, Philippe; Huvet, Arnaud; Suquet, Marc; Berchel, Mathieu; Paul-pont, Ika.
While the detection and quantification of nano-sized plastic in the environment remains a challenge, the growing number of polymer applications mean that we can expect an increase in the release of nanoplastics into the environment by indirect outputs. Today, very little is known about the impact of nano-sized plastics on marine organisms. Thus, the objective of this study was to investigate the toxicity of polystyrene nanoplastics (NPs) on oyster (Crassostrea gigas) gametes. Spermatozoa and oocytes were exposed to four NPs concentrations ranging from 0.1 to 100 mg L−1 for 1, 3 and 5 h. NPs coated with carboxylic (PS-COOH) and amine groups (PS-NH2) were used to determine how surface properties influence the effects of nanoplastics. Results demonstrated the...
Tipo: Text Palavras-chave: Nanoplastics; Oysters; Gametes; Cellular responses.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00443/55459/56976.pdf
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Constraints and Priorities for Conducting Experimental Exposures of Marine Organisms to Microplastics ArchiMer
Paul-pont, Ika; Tallec, Kevin; Gonzalez-fernandez, Carmen; Lambert, Christophe; Vincent, Dorothee; Mazurais, David; Zambonino-infante, Jose-luis; Brotons, Guillaume; Lagarde, Fabienne; Fabioux, Caroline; Soudant, Philippe; Huvet, Arnaud.
Marine plastic pollution is a major environmental issue. Given their ubiquitous nature and small dimensions, ingestion of microplastic (MP) and nanoplastic (NP) particles and their subsequent impact on marine life are a growing concern worldwide. Transfers along the trophic chain, including possible translocation, for which the hazards are less understood, are also a major preoccupation. Effects of MP ingestion have been studied on animals through laboratory exposure, showing impacts on feeding activity, reserve depletion and inflammatory responses, with consequences for fitness, notably reproduction. However, most experimental studies have used doses of manufactured virgin microspheres that may not be environmentally realistic. As for most...
Tipo: Text Palavras-chave: Microplastics; Nanoplastics; Experimental exposure; Impacts; Marine organisms; Physiology.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00449/56088/57621.pdf
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Nanoplastics impaired oyster free living stages, gametes and embryos ArchiMer
Tallec, Kevin; Huvet, Arnaud; Di Poi, Carole; Gonzalez-fernandez, Carmen; Lambert, Christophe; Petton, Bruno; Le Goic, Nelly; Berchel, Mathieu; Soudant, Philippe; Paul-pont, Ika.
In the marine environment, most bivalve species base their reproduction on external fertilization. Hence, gametes and young stages face many threats, including exposure to plastic wastes which represent more than 80% of the debris in the oceans. Recently, evidence has been produced on the presence of nanoplastics in oceans, thus motivating new studies of their impacts on marine life. Because no information is available about their environmental concentrations, we performed dose-response exposure experiments with polystyrene particles to assess the extent of micro/nanoplastic toxicity. Effects of polystyrene with different sizes and functionalization (plain 2-μm, 500-nm and 50-nm; COOH-50 nm and NH2-50 nm) were assessed on three key reproductive steps...
Tipo: Text Palavras-chave: Oyster; Embryos; Gametes; Microplastics; Nanoplastics.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00453/56419/58090.pdf
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Surface functionalization determines behavior of nanoplastic solutions in model aquatic environments ArchiMer
Tallec, Kevin; Blard, Océane; González-fernández, Carmen; Brotons, Guillaume; Berchel, Mathieu; Soudant, Philippe; Huvet, Arnaud; Paul-pont, Ika.
Plastic debris are classified as a function of their size and recently a new class was proposed, the nanoplastics. Nano-sized plastics have a much greater surface area to volume ratio than larger particles, which increases their reactivity in aquatic environment, making them potentially more toxic. Only little information is available about their behavior whereas it crucially influences their toxicity. Here, we used dynamic light scattering (DLS) to explore the influence of environmental factors (fresh- and saltwater, dissolved organic matter) on the behavior (surface charge and aggregation state) of three different nano-polystyrene beads (50 nm), with (i) no surface functionalization (plain), (ii) a carboxylic or (iii) an amine functionalization. Overall,...
Tipo: Text Palavras-chave: Nanoplastic; Dynamic light scattering; Behavior; Aggregation; Salinity; Organic matter.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00485/59652/62684.pdf
Registros recuperados: 6
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