Consulta: subjectFacets:"Harmful algae"
Registros recuperados: 16
Data/hora: 07/06/2024 09:43:06

Cellular and biochemical responses of the oyster Crassostrea gigas to controlled exposures to metals and Alexandrium minutum
Provedor de dados: 5
Autores: Haberkorn, Hansy; Lambert, Christophe; Le Goic, Nelly; Quere, Claudie; Bruneau, A; Riso, Ricardo; Auffret, Michel; Soudant, Philippe.
Effects of simultaneous exposure of Pacific oyster, Crassostrea gigas, to both a harmful dinoflagellate that produces Paralytic Shellfish Toxins (PST), Alexandrium minutum, and cadmium (Cd) and copper (Cu), were assessed. Oysters were exposed to a mix of Cd-Cu with two different diets (i.e. A. minutum or Tisochrysis lutea) and compared to control oysters fed A. minutum or T. lutea, respectively, without metal addition. Metals and PST accumulations, digestive gland lipid composition, and cellular and biochemical hemolymph variables were measured after 4 days of exposure. Oysters exposed to Cd-Cu accumulated about thirty-six times less PSTs than oysters exposed to A. minutum alone. Exposure to Cd-Cu induced significant changes in neutral lipids (increase in...
Tipo: Text
Palavras-chave: Harmful algae; Metals; Oysters; Toxin accumulation; Physiological effects.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00169/28071/26286.pdf

Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios
Provedor de dados: 5
Autores: Abi-khalil, Celina; Lopez-joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc.
The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium...
Tipo: Text
Palavras-chave: Harmful algae; Environment; Interaction; Pathogens; Defense; Paralytic shellfish toxin.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00309/42016/41308.pdf

Changes in the annual harmful algal blooms of     Alexandrium minutum     : effects of environmental conditions and drainage basin inputs in the Rance estuary (Brittany, France)
Provedor de dados: 5
Autores: Le Bec, Claude; Legendre, Aurelie; Messiaen, Gregory.
Time series of physico-chemical data and concentrations (cell L-1) of the toxic dinoflagellate Alexandrium minutum collected in the Rance macrotidal estuary (Brittany, France) were analyzed to understand the physico-chemical processes of the estuary and their relation to changes in bloom development from 1996 to 2009. The construction of the tidal power plant in the north and the presence of a lock in the south have greatly altered hydrodynamics, blocking the zone of maximum turbidity upstream, in the narrowest part of the estuary. Alexandrium minutum occurs in the middle part of the estuary. Most physical and chemical parameters of the Rance estuary are similar to those observed elsewhere in Brittany with water temperatures between 15–18 °C, slightly...
Tipo: Text
Palavras-chave: Harmful algae; Dinoflagellate; Nutrients; Eutrophication; Drainage basin; Land runoff.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00341/45257/44698.pdf

Dynamics of phytoplankton communities in eutrophying tropical shrimp ponds affected by vibriosis
Provedor de dados: 5
Autores: Lemonnier, Hugues; Lantoine, Francois; Courties, Claude; Guillebault, Delphine; Nezan, Elisabeth; Chomerat, Nicolas; Escoubeyrou, Karine; Galinie, Christian; Blockmans, Bernard; Laugier, Thierry.
Tropical shrimp aquaculture systems in New Caledonia regularly face major crises resulting from outbreaks of Vibrio infections. Ponds are highly dynamic and challenging environments and display a wide range of trophic conditions. In farms affected by vibriosis, phytoplankton biomass and composition are highly variable. These conditions may promote the development of harmful algae increasing shrimp susceptibility to bacterial infections. Phytoplankton compartment before and during mortality outbreaks was monitored at a shrimp farm that has been regularly and highly impacted by these diseases. Combining information from flow cytometry, microscopy, pigment and phylogenetic analysis, the presence of Picocyanobacteria, Prasinophyceae and Diatomophyceae were...
Tipo: Text
Palavras-chave: Tropical aquaculture pond; Litopenaeus stylirostris; Vibriosis; Eutrophication; Phytoplankton; Harmful algae.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00343/45411/44986.pdf

Relationship between valve activity, microalgae concentration in the water and toxin accumulation in the digestive gland of the Pacific oyster Crassostrea gigas exposed to Alexandrium minutum
Provedor de dados: 5
Autores: Haberkorn, Hansy; Tran, Damien; Massabuau, Jean-charles; Ciret, Pierre; Savar, Veronique; Soudant, Philippe.
The complexity of the relationships between Alexandrium minutum (Am.) concentration in the water ([A.m.](w)), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP](dg)) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters' valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10 x 10(3) cells ml(-1) (experiment-1) and 5 x 10(3) cells ml(-1) (experiment-2): 100% Am.; 50% A.m.-50% H.t.; 25% A.m.-75% H.t.; 100% H.t. At the end of experiment-2, [PSP](dg) were measured. At 10 x 103 cells ml(-1), the microalgal ingestion decreased...
Tipo: Text
Palavras-chave: Harmful algae; Oysters; Behavioral responses; Algae concentration; Toxin accumulation.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00041/15195/12617.pdf

Effects of Alexandrium minutum exposure on nutrition-related processes and reproductive output in oysters Crassostrea gigas
Provedor de dados: 5
Autores: Haberkorn, Hansy; Lambert, Christophe; Le Goic, Nelly; Moal, Jeanne; Suquet, Marc; Gueguen, Marielle; Sunila, Inke; Soudant, Philippe.
This study assessed the effects of an artificial bloom of the toxin-producing dinoflagellate, Alexandrium minutum, upon nutrition related processes and reproductive output of the Pacific oyster, Crassostrea gigas. Oysters were exposed to A. minutum, Paralytic Shellfish Toxins (PST) producer and compared to a control batch of oysters fed Isochrysis galbana clone Tahitian (T.Iso). The experiment was performed in June 2008, when oysters were found ripe. Several physiological variables of oysters, such as PSTs accumulation, digestive gland and histological observations as well as spermatozoa quality, were measured at the end of the exposure. Results indicate that the digestive gland was greatly impacted upon A. minutum exposure. Monoacylglycerol and...
Tipo: Text
Palavras-chave: Harmful algae; Alexandrium minutum; Oyster; Nutrition-related processes; Reproductive output.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00008/11927/8653.pdf

Influence of sudden salinity variation on the physiology and domoic acid production by two strains of   Pseudo-nitzschia australis
Provedor de dados: 5
Autores: Ayache, Nour; Hervé, Fabienne; Martin-jézéquel, Veronique; Amzil, Zouher; Caruana, Amandine.
Several coastal countries including France have experienced serious and increasing problems related to Pseudo‐nitzschia toxic blooms. These toxic blooms occur in estuarine and coastal waters potentially subject to fluctuations in salinity. In this study, we document for the first time the viability, growth, photosynthetic efficiency and toxin production of two strains of Pseudo‐nitzschia australis grown under conditions with sudden salinity changes. Following salinity variation, the two strains survived over a restricted salinity range of 30 to 35, with favorable physiological responses, as the growth, effective quantum yield and toxin content were high compared to the other conditions. In addition, high cellular quotas of domoic acid (DA) were observed at...
Tipo: Text
Palavras-chave: Amnesic shellfish poisoning; Domoic acid; Harmful algae; Pseudo-nitzschia australis; Salinity stress.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00462/57385/59465.pdf

Atlas of modern dinoflagellate cyst distributions in the Black Sea Corridor: From Aegean to Aral Seas, including Marmara, Black, Azov and Caspian Seas
Provedor de dados: 5
Autores: Mudie, Peta J.; Marret, Fabienne; Mertens, Kenneth; Shumilovskikh, Lyudmila; Leroy, Suzanne A. G.
We present the first comprehensive taxonomic and environmental study of dinoflagellate cysts in 185 surface sediment samples from the Black Sea Corridor (BSC) which is a series of marine basins extending from the Aegean to the Aral Seas (including Marmara, Black, Azov and Caspian Seas). For decades, these low-salinity, semi-enclosed or endorheic basins have experienced large-scale changes because of intensive agriculture and industrialisation, with consequent eutrophication and increased algal blooms. The BSC atlas data provide a baseline for improved understanding of linkages between surface water conditions and dinoflagellate cyst (dinocyst) distribution, diversity and morphological variations. By cross-reference to dinocyst occurrences in sediment cores...
Tipo: Text
Palavras-chave: Phytoplankton; Harmful algae; Biodiversity; Paleoceanography; Surface samples.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00387/49824/50408.pdf

Azaspiracid Toxins: Toxicological Profile
Provedor de dados: 5
Autores: Hess, Philipp; Twiner, Michael J; Kilcoyne, Jane; Sosa, Sylvio.
Azaspiracids (AZAs) are a toxin group that originate from marine dinoflagellates of the genera Azadinium and Amphidoma. After accumulation of these toxins in edible marine organisms and their subsequent consumption, humans develop a gastrointestinal syndrome referred to as azaspiracid shellfish poisoning (AZP). This syndrome is very similar to diarrheic shellfish poisoning (DSP), with main symptoms appearing after a few hours from consumption and including diarrhea, vomiting, and stomach cramps. Due to extensive metabolism in shellfish, more than 30 analogues have been reported to date, and purified compounds for selected analogues have recently been made available for toxicological studies. Currently, only AZA1, AZA2, and AZA3 are regulated in Europe and...
Tipo: Text
Palavras-chave: Azaspiracids; Azaspiracid shellfish poisoning; Harmful algae; Azadinium; Shellfish.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00320/43146/42744.pdf

Overview of eutrophication indicators to assess environmental status within the European Marine Strategy Framework Directive
Provedor de dados: 5
Autores: Ferreira, Joao G.; Andersen, Jesper H.; Borja, Angel; Bricker, Suzanne B.; Camp, Jordi; Da Silva, Margarida Cardoso; Garces, Esther; Heiskanen, Anna-stiina; Humborg, Christoph; Ignatiades, Lydia; Lancelot, Christiane; Menesguen, Alain; Tett, Paul; Hoepffner, Nicolas; Claussen, Ulrich.
In 2009, following approval of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), the European Commission (EC) created task groups to develop guidance for eleven quality descriptors that form the basis for evaluating ecosystem function. The objective was to provide European countries with practical guidelines for implementing the MSFD, and to produce a Commission Decision that encapsulated key points of the work in a legal framework. This paper presents a review of work carried out by the eutrophication task group, and reports our main findings to the scientific community. On the basis of an operational, management-oriented definition, we discuss the main methodologies that could be used for coastal and marine eutrophication assessment....
Tipo: Text
Palavras-chave: Eutrophication; Chlorophyll; Dissolved oxygen; Harmful algae; Marine; Coastal; Assessment methods; Europe; Marine Strategy Framework Directive; Water Framework Directive.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00039/15055/12609.pdf

The role of hydrographic parameters, measured from a ship of opportunity, in bloom formation of Karenia mikimotoi in the English Channel
Provedor de dados: 5
Autores: Hartman, S.e.; Hartman, M. C.; Hydes, D.j.; Smythe-wright, D.; Gohin, Francis; Lazure, Pascal.
Unusually high chlorophyll values (~ 14 mg chl m− 3 at 5 m depth), recorded on a ship of opportunity (SOO) in July 2010, indicated the occurrence of a potential Harmful Algal Bloom (HAB) in the Western approaches of the English Channel. This bloom, located at 49.7°N, 3.2°W was observed via complementary datasets. These included data from samples collected for microscopic phytoplankton identification, information from satellite maps to follow geographical bloom development and in situ data to identify hydrographic factors related to bloom initiation. The relationships between chlorophyll-fluorescence, temperature, salinity and wind speed were examined. The intense summer bloom predominantly consisted of the dinoflagellate Karenia mikimotoi and followed an...
Tipo: Text
Palavras-chave: Karenia mikimotoi; Harmful algae; Wind speed; Temperature; Low salinity water; French Atlantic rivers; English Channel; Ferry-box.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00199/31033/29437.pdf

Acute Oral Toxicity of Pinnatoxin G in Mice
Provedor de dados: 5
Autores: Sosa, Silvio; Pelin, Marco; Cavion, Federica; Herve, Fabienne; Hess, Philipp; Tubaro, Aurelia.
Pinnatoxin G (PnTx-G) is a marine cyclic imine toxin produced by the dinoflagellate Vulcanodinium rugosum, frequently detected in edible shellfish from Ingril Lagoon (France). As other pinnatoxins, to date, no human poisonings ascribed to consumption of PnTx-G contaminated seafood have been reported, despite its potent antagonism at nicotinic acetylcholine receptors and its high and fast-acting toxicity after intraperitoneal or oral administration in mice. The hazard characterization of PnTx-G by oral exposure is limited to a single acute toxicity study recording lethality and clinical signs in non-fasted mice treated by gavage or through voluntary food ingestion, which showed differences in PnTx-G toxic potency. Thus, an acute toxicity study was carried...
Tipo: Text
Palavras-chave: Vulcanodinium rugosum; Pinnatoxin G; Dinoflagellates; Harmful algae; Oral toxicity.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00605/71724/70190.pdf

The paralytic shellfish toxin, saxitoxin, enters the cytoplasm and induces apoptosis of oyster immune cells through a caspase-dependent pathway
Provedor de dados: 5
Autores: Abikhalil, Celina; Finkelstein, Darren S.; Conejero, Genevieve; Du Bois, Justin; Destoumieux-garzon, Delphine; Rolland, Jean-luc.
Exposure of the toxin-producing dinoflagellate Alexandrium catenella (A. catenella) was previously demonstrated to cause apoptosis of hemocytes in the oyster species Crassostrea gigas. In this work, a coumarin-labeled saxitoxin appeared to spread throughout the cytoplasm of the hemocytes. PSTs, including saxitoxin, were also shown to be directly responsible for inducing apoptosis in hemocytes, a process dependent on caspase activation and independent of reactive oxygen species (ROS) production. A series of in vitro labeling and microscopy experiments revealed that STX and analogs there of induced nuclear condensation, phosphatidylserine exposure, membrane permeability, and DNA fragmentation of hemocytes. Unlike in vertebrates, gonyautoxin-5 (GTX5), which...
Tipo: Text
Palavras-chave: Shellfish; Toxin; Harmful algae; Phytoplankton.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00391/50272/50905.pdf

Screening the toxicity and toxin content of blooms of the cyanobacterium Trichodesmium erythraeum (Ehrenberg) in northeast Brasil
Provedor de dados: 80
Autores: Proença,LAO; Tamanaha,MS; Fonseca,RS.
Blooms of the cyanobacterium Trichodesmium occur in massive colored patches over large areas of tropical and subtropical oceans. Recently, the interest in such events has increased given their role in major nitrogen and carbon dioxide oceanic fluxes. Trichodesmium occurs all along the Brazilian coast and patches frequently migrate towards the coast. In this paper we screen the toxicity and toxin content of Trichodesmium blooms off the coast of Bahia state. Four samples, collected from February to April 2007, were analyzed. Organisms were identified and assessed for toxicity by means of several methods. Analogues of microcystins, cylindrospermopsins and saxitoxins were analyzed using HPLC. Microcystins were also assayed through ELISA. Results showed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Saxitoxin; Microcystin; Harmful algae; Trichodesmium; Bloom.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992009000200004

Cyanobacteria, microcystins and cylindrospermopsin in public drinking supply reservoirs of Brazil
Provedor de dados: 42
Autores: BITTENCOURT-OLIVEIRA,MARIA DO CARMO; PICCIN-SANTOS,VIVIANE; MOURA,ARIADNE N.; ARAGÃO-TAVARES,NÍSIA K.C.; CORDEIRO-ARAÚJO,MICHELINE K.
Brazil has a history of blooms and contamination of freshwater systems by cyanobacterial toxins. The monitoring relevance of toxins from cyanobacteria in reservoirs for public supply is notorious given its high toxicity to mammals, included humans beings. The most recurrent toxins in Brazilian water bodies are microcystins (MC). However, the recent record of cylindrospermopsin (CYN) in northeastern Brazil, Pernambuco state, alerts us to the possibility that this could be escalating. This study reports occurrence of MC and CYN, quantified with ELISA, in 10 reservoirs, devoted to public drinking supply in northeastern Brazil. The composition and quantification of the cyanobacteria community associated with these water bodies is also presented. From 23...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bloom; Harmful algae; Monitoring; Toxin; Water quality.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000100297

Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables
Provedor de dados: 42
Autores: WOJCIECHOWSKI,JULIANA; PADIAL,ANDRÉ A.
One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Harmful algae; Reservoir; Management; Limnological variables; Temporal variation; Neotropics.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000401717