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Seguin V.,University of Caen Lower Normandy | Gente S.,University of Caen Lower Normandy | Heutte N.,University of Caen Lower Normandy | Verite P.,University of Rouen | And 4 more authors.
World Mycotoxin Journal | Year: 2014

Mycophenolic acid is considered as an immunosuppressive pharmaceutical drug, but also as a mycotoxin due to its undesirable presence in various feedstuffs. Although Penicillium brevicompactum has been historically identified as the major producer of mycophenolic acid, this study reports for the first time the production of mycophenolic acid by isolates of Eurotium repens collected from agricultural and indoor environments. Fungal identification was achieved by scanning electron microscopy and molecular techniques, and mycophenolic acid production was confirmed by two analytical methods (gas and liquid chromatography coupled to mass spectrometry). These findings suggest that mycophenolic acid production and immunosuppressive properties of other closely related Eurotium should be evaluated in future studies.

Jouaux A.,French National Center for Scientific Research | Jouaux A.,University of Caen Lower Normandy | Lafont M.,French National Center for Scientific Research | Lafont M.,University of Caen Lower Normandy | And 7 more authors.
BMC Genomics | Year: 2013

Background: Massive mortalities have been observed in France since 2008 on spat and juvenile Pacific oysters, Crassostrea gigas. A herpes virus called OsHV-1, easily detectable by PCR, has been implicated in the mortalities as demonstrated by the results of numerous field studies linking mortality with OsHV-1 prevalence. Moreover, experimental infections using viral particles have documented the pathogenicity of OsHV-1 but the physiological responses of host to pathogen are not well known.Results: The aim of this study was to understand mechanisms brought into play against the virus during infection in the field. A microarray assay has been developed for a major part of the oyster genome and used for studying the host transcriptome across mortality on field. Spat with and without detectable OsHV-1 infection presenting or not mortality respectively were compared by microarray during mortality episodes. In this study, a number of genes are regulated in the response to pathogen infection on field and seems to argue to an implication of the virus in the observed mortality. The result allowed establishment of a hypothetic scheme of the host cell's infection by, and response to, the pathogen.Conclusions: This response shows a " sensu stricto" innate immunity through genic regulation of the virus OsHV-1 life cycle, but also others biological processes resulting to complex interactions between host and pathogens in general. © 2013 Jouaux et al.; licensee BioMed Central Ltd.

Martenot C.,Laboratoire Frank Duncombe | Fourour S.,Laboratoire Frank Duncombe | Oden E.,Laboratoire Frank Duncombe | Jouaux A.,University of Caen Lower Normandy | And 3 more authors.
Aquaculture | Year: 2012

Since the summer of 2008, the mortality of young Pacific oysters Crassotrea gigas has been greatly increased on the French coast and may be linked to a microvariant of the Ostreid Herpesvirus 1 (OsHV-1), named OsHV-1 μVar. This variant is mainly characterized by a deletion of 12 consecutive nucleotides followed by a deletion of one adenine in a microsatellite area located in the C region. The present study is the continuity of a previous study that was conducted on oysters collected from July 2008 to June 2010 (Martenot et al., 2011). The purpose of the current survey is to determine the genotype of oyster samples collected from July 2010 to August 2011 and samples taken before 2008. The OsHV-1 μVar was detected in 98% of characterized samples and the two new forms of microvariants were found in the remaining 2%. The first genotype has 15. bp successive deletions and the second genotype is similar to the OsHV-1 reference with an insertion of three nucleotides. The OsHV-1 μVar δ9 previously described in the literature was detected in a sample originating in Brittany. These observations reinforce the possibility of the emergence of different OsHV-1 variants. © 2011.

Since the 1990s, high mortality rates of young Pacific oysters Crassostrea gigas have been regularly recorded in France and affect mainly spat (oysters less than 1 year old). Pathogens infecting marine bivalve mollusks have been studied particularly due to their economic and ecologic impacts on the farmed and wild oysters. A herpes virus belonging to the family Malacoherpesviridae and called Ostreid Herpesvirus-1 (OsHV-1) has been detected in infected oysters. Since the summer 2008, the mortality of spat has greatly increased on the French coast (with a mortality rate ranging from 40 to 80%) and may be linked to a variant of the OsHV-1, named OsHV-1 μVar. Few variants of the OsHV-1 and genotypes closed to the OsHV-1 μVar have been described in several areas in the world. However, the OsHV-1 μVar is predominant in analyzed samples and the reference genotype of the OsHV-1 has not been detected since 2008. The causes of the emergence of the OsHV-1 μVar and its rapid spreading in the world are currently unknown.

During the summer of 2007, an outbreak of equine viral arteritis (EVA) occurred in Normandy (France). After investigation, a link was suggested between an EAV carrier stallion (A) and the index premise of the outbreak. The full-length nucleotide sequence analysis of a study reference strain (F27) isolated from the lung of a foal revealed a 12,710 nucleotides EAV genome with unique molecular hallmarks in the 5UTR leader sequence and the ORF1a sequence encoding the non-structural protein 2. The evolution of the viral population in the persistently infected Stallion A was then studied by cloning ORFs 3 and 5 of the EAV genome from four sequential semen samples which were collected between 2000 and 2007. Molecular analysis of the clones confirmed the likely implication of Stallion A in the origin of this outbreak through the yearly emergence of new variants genetically similar to the F27 strain.

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Loading Laboratoire Frank Duncombe collaborators