Consulta: creatorFacets:"Haberkorn, Hansy"
Registros recuperados: 12
Data/hora: 03/06/2024 08:20:37

Comparative study of three analysis methods (TTGE, flow cytometry and HPLC) for xenobiotic impact assessment on phytoplankton communities
Provedor de dados: 5
Autores: Stachowski-haberkorn, Sabine; Quiniou, Louis; Beker, Beatriz; Haberkorn, Hansy; Marie, Dominique; De La Broise, Denis.
The impacts of the fungicide Opus(A (R)) (epoxiconazole) on marine phytoplankton communities were assessed in a 12-day field experiment using in situ microcosms maintained underwater at 6 m depth. Three community analysis methods were compared for their sensitivity threshold in fungicide impact detection. When phytoplankton communities were exposed to 1 mu g l(-1) of epoxiconazole, no effects could be demonstrated using TTGE (Temporal Temperature Gradient gel Electrophoresis), flow cytometry or HPLC. When exposed to 10 mu g l(-1), TTGE fingerprints from PCR amplified 18S rDNA of communities exhibited significant differences compared with controls (ANOSIM, P = 0.028). Neither flow cytometry counts, nor HPLC pigment profiles allowed to show significant...
Tipo: Text
Palavras-chave: Microcosm; Phytoplankton community; Epoxiconazole; TTGE; Flow cytometry; HPLC.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00088/19888/17547.pdf

Effects of Alexandrium minutum exposure upon physiological and hematological variables of diploid and triploid oysters, Crassostrea gigas
Provedor de dados: 5
Autores: Haberkorn, Hansy; Lambert, Christophe; Le Goic, Nelly; Gueguen, Marielle; Moal, Jeanne; Palacios, Elena; Lassus, Patrick; Soudant, Philippe.
The effects of an artificial bloom of the toxin-producing dinoflagellate, Alexandrium minutum, upon physiological parameters of the Pacific oyster, Crassostrea gigas, were assessed. Diploid and triploid oysters were exposed to cultured A. minutum and compared to control diploid and triploid oysters fed T. Isochrysis. Experiments were repeated twice, in April and mid-May 2007, to investigate effects of maturation stage on oyster responses to A. minutum exposure. Oyster maturation stage, Paralytic Shellfish Toxin (PST) accumulation, as well as several digestive gland and hematological variables, were assessed at the ends of the exposures. In both experiments, triploid oysters accumulated more PSTs (approximately twice) than diploid oysters. Significant...
Tipo: Text
Palavras-chave: Oysters; Ploidy; Physiology; Harmful-algal bloom; Alexandrium minutum; PST accumulation.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00003/11378/7988.pdf

Communautés du phytoplancton. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Belin, Catherine; Haberkorn, Hansy; Ménesguen, Alain.
Tipo: Text
Palavras-chave: Mers celtiques; Communautés du phytoplancton; Biocénoses; Modélisation écologique; Synthèse bibliographique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43935/43508.pdf

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

Communautés du phytoplancton. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Belin, Catherine; Haberkorn, Hansy; Menesguen, Alain.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Communautés du phytoplancton; Biocénoses; Modélisation écologique; Synthèse bibliographique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43832/43406.pdf

Modelling of paralytic shellfish toxin biotransformations in the course of Crassostrea gigas detoxification kinetics
Provedor de dados: 5
Autores: Gueguen, Marielle; Baron, Regis; Bardouil, Michele; Truquet, Philippe; Haberkorn, Hansy; Lassus, Patrick; Barille, Laurent; Amzil, Zouher.
The aim of this study was to evaluate the importance of biotransformation of paralytic shellfish toxins during the detoxification process in contaminated oysters. Mathematical models based upon the detoxification patterns of digestive gland and other tissues were developed. It was demonstrated that biotransformations do not seem to play an important role in digestive gland or other tissue detoxification kinetics with our data set. Moreover, different toxin transfers from digestive gland toward other tissues were investigated. No significant transfer was highlighted in our data set. These first conclusions were drawn after comparing the results obtained from 13 biotransformations and identifiable transfer scenarios. Finally, to determine a more robust...
Tipo: Text
Palavras-chave: Detoxification kinetics modelling; Biotransformation of saxitoxin analogues; Oyster.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00049/16047/14309.pdf

Impact of Roundup on the marine microbial community, as shown by an in situ microcosm experiment
Provedor de dados: 5
Autores: Stachowski-haberkorn, Sabine; Becker, Beatriz; Marie, Dominique; Haberkorn, Hansy; Coroller, Louis; De La Broise, Denis.
The effects of the herbicide Roundup (R) (glyphosate) on natural marine microbial communities were assessed in a 7-day field experiment using microcosms. Bottles were maintained underwater at 6 m depth, and 10% of their water content was changed every other day. The comparison of control microcosms and surrounding surface water showed that the microcosm system tested here can be considered as representative of the natural surrounding environment. A temporal temperature gradient gel electrophoresis (TTGE) was run on 165 and 18S rDNA-amplified extracts from the whole microbial community. Cluster analysis of the 16S gel showed differences between control and treatment fingerprints for Roundup at 1 mu g L-1 (ANOSIM,p=0.055; R=0.53), and 10 mu g L-1 (ANOSIM,...
Tipo: Text
Palavras-chave: Microcosm; Marine microbial communities; Glyphosate; TTGE; Flow cytometry.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00088/19887/17546.pdf

Les communautés du phytoplancton. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Belin, Catherine; Haberkorn, Hansy; Ménesguen, Alain.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Phytoplancton; Communautés; Fréquence des blooms; Modélisation écologique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44014/43586.pdf

Influence of Crassostrea gigas (Thunberg) sexual maturation stage and ploidy on uptake of paralytic phycotoxins
Provedor de dados: 5
Autores: Gueguen, Marielle; Baron, Regis; Bardouil, Michele; Haberkorn, Hansy; Soudant, Philippe; Truquet, Philippe; Lassus, Patrick.
The purpose of this study was to assess paralytic phycotoxin uptake in diploid and triploid oysters at two stages of their sexual cycle corresponding to their status in early summer (June) and winter (November). Samples of diploid and triploid oysters were exposed to a toxic culture of Alexandrium minutum for 4 days in each season. No significant differences in filtration or clearance rates were observed during either November or June experiments. When diploid oysters were at resting stage (November), toxin uptake showed no significant difference between the ploidy classes. In contrast, when the diploid oysters were at the peak of their sexual maturation (June), the triploid oysters were seen to accumulate almost double the amount of paralytic toxins as...
Tipo: Text
Palavras-chave: Paralytic shellfish poisoning; Crassostrea gigas; Diploid; Triploid; Contamination.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19796/17487.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

Exposure to toxic Alexandrium minutum activates the detoxifying and antioxidant systems in gills of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Fabioux, Caroline; Sulistiyani, Yeni; Haberkorn, Hansy; Hegaret, Helene; Amzil, Zouher; Soudant, Philippe.
Harmful algal blooms of Alexandrium spp. dinoflagellates regularly occur in French coastal waters contaminating shellfish. Studies have demonstrated that toxic Alexandrium spp. disrupt behavioural and physiological processes in marine filter-feeders, but molecular modifications triggered by phycotoxins are less well understood. This study analyzed the mRNA levels of 7 genes encoding antioxidant/detoxifying enzymes in gills of Pacific oysters (Crassostrea gigas) exposed to a cultured, toxic strain of A. minutum, a producer of paralytic shellfish toxins (PST) or fed Tisochrysis lutea (T. lutea, formerly Isochrysis sp., clone Tahitian (T. iso)), a non-toxic control diet, in four repeated experiments. Transcript levels of sigma-class glutathione S-transferase...
Tipo: Text
Palavras-chave: Crassostrea gigas; Alexandrium minutum; Paralytic shellfish toxins; Antioxidant enzymes; Detoxification enzymes; MRNA.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38601/38623.pdf