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Vabret A.,University of Caen Lower Normandy | Miszczak F.,Laboratoire Departemental Franck Duncombe
Revue Francophone des Laboratoires

Viral tropism is defined as the group of target cells which can be infected by this virus. Knowing viral tropism is knowing the target organ, and the animal species used as host. The variation of tropism allow for virus to evolve, cross species barriers, and infect a new host. Coronavirus family is a very large group of viruses which infect birds and mammals. These RNA viruses can rapidly evolve. In the history of coronaviruses, several examples of variations of tropism have been described, and have as consequences the emergence of a new infection (coronavirus associated with SARS, porcine respiratory coronavirus), or a new expression of the clinical presentation of the infection (fatal infectious peritonitis in cats and ferrets).. © 2010 - Elsevier Masson SAS - Tous droits réservés. Source

Klein C.,University of Caen Lower Normandy | Claquin P.,University of Caen Lower Normandy | Bouchart V.,Laboratoire Departemental Franck Duncombe | Le Roy B.,University of Caen Lower Normandy | Veron B.,University of Caen Lower Normandy
Harmful Algae

Temporal variations in the Pseudo-nitzschia assemblage were characterized in the Baie des Veys (Normandy, France) from July 2007 to July 2008. This study describes the succession of Pseudo-nitzschia species. Six species were identified, Pseudo-nitzschia americana, P. australis, P. delicatissima, P. fraudulenta, P. multistriata, and P. pungens and their occurrences were related to physical, chemical and biological factors. Pseudo-nitzschia spp. were observed during the whole year, the higher abundance (38 × 103 cell L-1) and diversity were found in September while the lowest (0.9 × 103 cell L-1) were observed from October to the end of February. P. americana and P. australis were only seen in September and were positively correlated with high chlorophyll a, temperature and Si(OH)4 concentrations. P. delicatissima and P. fraudulenta were more abundant under high NO3 and low Si(OH)4 concentrations and associated with low chlorophyll a concentrations. P. multistriata appeared in October and in November 2007 and its abundance was correlated with NH4 while P. pungens abundance was not related to any environmental factors tested suggesting high acclimation capacities. In September 2007, P. australis was observed and domoic acid (7.1 ng DA L-1) was measured in the phytoplankton samples. During this period, the phytoplankton population was mostly limited by PO4 and NO3 concentrations. On 17 September a heavy rainfall (15.6 mm) affected the nutrient stocks resulting in Si(OH)4 and NO3 limitations. Our results suggest that this Si(OH)4 limitation might have promoted the production of domoic acid by P. australis. This study presents the first results on Pseudo-nitzschia successions and particulate domoic acid concentrations on the French coasts. This work especially highlights the beginning of autumn as a potential risk period for ASP events linked to P. australis development in the Baie de Seine. © 2009 Elsevier B.V. All rights reserved. Source

Buron N.,ADRIA NORMANDIE | Buron N.,University of Caen Lower Normandy | Coton M.,ADRIA NORMANDIE | Legendre P.,Laboratoire Departemental Franck Duncombe | And 5 more authors.
International Journal of Food Microbiology

Different Lactobacillus collinoides and Brettanomyces/Dekkera anomala cider strains were studied for their ability to produce volatile phenols in synthetic medium. All strains were able to produce 4-ethylcatechol (4-EC), 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) from caffeic, p-coumaric and ferulic acids, respectively. Interestingly, D. anomala and L. collinoides were also able to produce 4-EC, 4-EP and 4-EG in cider conditions. The quantities of ethylphenols produced by these two species were similar in both tested ciders. The impact of precursor quantities was studied and it showed that the addition of caffeic and p-coumaric acids in ciders allowed for higher 4-EC and 4-EP production by D. anomala and L. collinoides. In parallel, D. anomala and L. collinoides strains were isolated from a phenolic off-flavour defective bottled cider after ethylphenol production hence confirming the implication of these two species in this cider spoilage. Finally, detection thresholds of the main ethylphenols were determined in ciders by orthonasal and retronasal sampling. The 4-EC and 4-EP detection thresholds (close to 20-25. mg/l and 1.5-2.0. mg/l, respectively) were matrix dependant. © 2011 Elsevier B.V. Source

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