Consulta: creatorFacets:"Thomas-guyon, Helene"
Registros recuperados: 6
Data/hora: 19/05/2024 10:36:36

Comparison of hemocyte parameters in the pericardial cavity and the adductor muscle sinus in the Pacific oyster, Crassostrea gigas using two types of flow cytometers
Provedor de dados: 5
Autores: Gagnaire, Beatrice; Duchemin, M; Auffret, Mathieu; Thomas-guyon, Helene; Renault, Tristan.
Parameters of hemocyte populations have been considered as relevant indicators of bivalve health and are currently used in immunotoxicological studies. Hemocytes in hemolymph can be collected by puncturing either the pericardial cavity or the adductor muscle sinus with a syringe. Flow cytometry is a methodological approach that is increasingly being used in laboratories for the study of hemocyte parameters in aquatic invertebrates. However, various protocols for hemocyte processing in laboratories equipped with different types of cytometers have been published. In this context, two flow cytometers ( EPICS XL4 (R), Beckman Coulter and FacsCalibur (R), Becton Dickinson) and two sites of hemocyte collection ( pericardial cavity and adductor muscle sinus) were...
Tipo: Text
Palavras-chave: Crassostrea gigas; Phagocytosis; Hemocytes; Flow cytometry.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3898.pdf

Demonstration of a true phenoloxidase activity and activation of a ProPO cascade in Pacific oyster, Crassostrea gigas (Thunberg) in vitro
Provedor de dados: 5
Autores: Hellio, Claire; Bado Nilles, Anne; Gagnaire, Beatrice; Renault, Tristan; Thomas-guyon, Helene.
The prophenoloxidase (ProPO) system is the origin of melanin production and is considered to be an innate defence mechanism in invertebrates. In different bivalve species, phenoloxidase (PO) is present in the haemolymph as an inactive form of ProPO. The present study focuses on the Pacific adult oyster, Crassostrea gigas, an economically important bivalve species along French coasts. The results indicate that many factors may inhibit the PO-like activity. These include: phenylthiourea (PTU), sodium diethylthiocarbamate (DETC), beta-mercaptoethanol and tropolone, which repressed the spontaneous PO activity. The activation of PO-like activity in C. gigas acellular fraction by lipopolysaccharide (LPS) involved participation of other factors, including at...
Tipo: Text
Palavras-chave: Prophenoloxidase; Phenoloxidase; Oyster; Immunity; Defence; Crassostrea gigas.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2926.pdf

Detection of early effects of a single herbicide (diuron) and a mix of herbicides and pharmaceuticals (diuron, isoproturon, ibuprofen) on immunological parameters of Pacific oyster (Crassostrea gigas) spat
Provedor de dados: 5
Autores: Luna-acosta, Andrea; Renault, Tristan; Thomas-guyon, Helene; Faury, Nicole; Saulnier, Denis; Budzinski, Helene; Le Menach, K.; Pardon, P.; Fruitier-arnaudin, I.; Bustamante, Paco.
In the context of massive summer mortality events of the Pacific oyster Crassostrea gigas, the aim of this study was to investigate the early effects on genes, enzymes and haemocyte parameters implicated in immune defence mechanisms in C. gigas oysters exposed to a potentially hostile environment, i.e. to an herbicide alone or within a mixture. Following 2 h of exposure to the herbicide diuron at 1 mu g L-1 the repression of different genes implicated in immune defence mechanisms in the haemocytes and the inhibition of enzyme activities, such as laccase-type phenoloxidase (PO) in the plasma, were observed. The inhibition of superoxide dismutase (SOD) activity in the plasma was also observed after 6 and 24 h of exposure. In the mixture with the herbicides...
Tipo: Text
Palavras-chave: Bivalve; Pollution; Gene expression; Laccase; Superoxide dismutase; Phagocytosis.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00083/19435/17475.pdf

Effects of 16 pure hydrocarbons and two oils on haemocyte and haemolymphatic parameters in the Pacific oyster, Crassostrea gigas (Thunberg)
Provedor de dados: 5
Autores: Bado Nilles, A; Gagnaire, Beatrice; Thomas-guyon, Helene; Le Floch, S; Renault, Tristan.
The in vitro effects of polycyclic aromatic hydrocarbons (PAHs) on haemocyte and haemolymphatic parameters of the Pacific oyster, Crassostrea gigas, were tested using field concentrations (10(-7) and 10(-9) mg mL(-1)) observed in the Marennes-Oleron Basin (Charente-Maritime, France) and high concentrations (10(-3) and 10(-5) mg mL(-1)) observed during oil spills. As a first step, the effects of pollutants, after a 24 h contamination period, were monitored on individual and pooled haemolymph samples and similar results were observed for both sample types. In a second step, haemolymphs from 45 oysters were withdrawn and pooled. Eighteen pollutants were tested in vitro after a 4 and 24 h contamination period and 10 of them showed significant modulations of...
Tipo: Text
Palavras-chave: Toxicity; PAHs; Pacific oyster; Spectrophotometry; Flow cytometry; Haemocyte activity.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4696.pdf

Effects of cadmium on aneuploidy and hemocyte parameters in the Pacific oyster, Crassostrea gigas
Provedor de dados: 5
Autores: Bouilly, Karine; Gagnaire, Beatrice; Bonnard, Marc; Thomas-guyon, Helene; Renault, Tristan; Miramand, Pierre; Lapegue, Sylvie.
Pacific oysters, Crassostrea gigas, are commonly reared in estuaries where they are exposed to anthropogenic pollution. Much research has been made on the toxicity of cadmium to aquatic organisms because the compound recurrently contaminates their environment. Our study examined the influence of cadmium on aneuploidy level (lowered chromosome number in a percentage of somatic cells) and hemocyte parameters in C. gigas at different stages of life. Adults and juveniles were exposed to two different concentrations of cadmium. The first concentration applied was equivalent to a peak value found in Marennes-Oleron bay (Charente-Maritime, France; 50 ng L-1) and the second was 10 times higher (500 ng L-1). Exposure to 50 ng L-1 cadmium caused a significant...
Tipo: Text
Palavras-chave: Phenoloxidase; Flow cytometry; Hemocytes; Aneuploidy; Crassostrea gigas; Cadmium.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1687.pdf

First evidence of a potential antibacterial activity involving a laccase-type enzyme of the phenoloxidase system in Pacific oyster Crassostrea gigas haemocytes
Provedor de dados: 5
Autores: Luna-acosta, Andrea; Saulnier, Denis; Pommier, Mylene; Haffner, Philippe; De Decker, Sophie; Renault, Tristan; Thomas-guyon, Helene.
Phenoloxidases (POs) are a group of copper proteins including tyrosinase, catecholase and laccase. In several insects and crustaceans, antibacterial substances are produced through the PO cascade, participating in the direct killing of invading microorganisms. However, although POs are widely recognised as an integral part of the invertebrate immune defence system, experimental evidence is lacking that these properties are conserved in molluscs, and more particularly in the Pacific oyster Crassostrea gigas. In the present study, Vibrio splendidus LGP32 and Vibrio aestuarianus 02/041 growths were affected, after being treated with C. gigas haemocyte lysate supernatant (HLS), and either a common substrate of POs, l-3,4-dihydroxyphenylalanine (l-DOPA), to...
Tipo: Text
Palavras-chave: Phenoloxidases; Antibacterial activity; Vibrio; Bivalve; Immunity.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00045/15598/13001.pdf