Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas
Oyster-farming in France is mainly based on pacific cupped oysters, Crassostrea gigas culture. Currently, oyster culture is confronted by several abnormal episodes of mass mortality affecting all life stages. These outbeaks involve, among other factors, infectious agents including bacteria of the ge...
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fttriple:oai:gotriple.eu:10670/1.7lg16g 2023-05-15T15:58:03+02:00 Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas Étude de la pathogénèse de Vibrio aestuarianus, une bactérie affectant l’huître creuse Crassostrea gigas Parizadeh, Leila La Rochelle Travers, Marie-Agnès 2018-11-08 http://www.theses.fr/2018LAROS027 fr fre 10670/1.7lg16g http://www.theses.fr/2018LAROS027 other Theses.fr Huître creuse C. gigas V. aestuarianus Pathogenèse Cycle d'infectieux Virulence bactérienne Régulation de l’expression des gènes Cupped oysters Pathogenesis Infectious cycle Bacterial virulence Regulation of gene expression geo envir Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2018 fttriple 2023-01-22T17:05:41Z Oyster-farming in France is mainly based on pacific cupped oysters, Crassostrea gigas culture. Currently, oyster culture is confronted by several abnormal episodes of mass mortality affecting all life stages. These outbeaks involve, among other factors, infectious agents including bacteria of the genus Vibrio. In France, since 2000, V. aestuarianus is known as a bacterium that impacts the survival of C. gigas. Since 2011, its detection frequency in adult oyster mortalities cases reported by REPAMO network (REseau de PAthologie des Mollusques), is constantly increasing. In this context, to study V. aestuarianus disease development in C. gigas, an experimental infection model based on immersion in sea water containing freshly shed bacteria was developed. By monitoring the presence of strain 12/016 (virulent strain) and its mutant 12/016 ΔvarS (non-virulent strain) in the seawater, in the different tissues and in the haemolymph of live and moribund animals, we showed that the infectious cycle consists of several successive phases: I) rapid penetration of the bacterium into the host (less than 24 hours) and initial colonization of the haemolymph and gills, II) 3-4 days of incubation during which the virulent strain multiplies in whole oyster tissues and III) acute mortalities (animal death due to septicemia). At this stage, recruitment and haemocyte lysis as well as different tissue lesions such as lysis of the sub-epithelial connective tissue in the mantle and atrophy of digestive diverticula were observed. On the other hand, relative expression of 18 virulence genes (known in other Vibrion) were analyzed by RT-QPCR. Virulence factors are regulated differently during different stages of infection and vam metalloprotease is significantly over-expressed in the haemolymph of infected animals at day 4 post infection (intermediate stage of infection) compared to its level of expression at day 1 post infection (early stage). L’ostréiculture française repose essentiellement sur l’élevage de l’huître creuse, Crassostrea ... Thesis Crassostrea gigas Pacific oyster Unknown Pacific |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
French |
topic |
Huître creuse C. gigas V. aestuarianus Pathogenèse Cycle d'infectieux Virulence bactérienne Régulation de l’expression des gènes Cupped oysters Pathogenesis Infectious cycle Bacterial virulence Regulation of gene expression geo envir |
spellingShingle |
Huître creuse C. gigas V. aestuarianus Pathogenèse Cycle d'infectieux Virulence bactérienne Régulation de l’expression des gènes Cupped oysters Pathogenesis Infectious cycle Bacterial virulence Regulation of gene expression geo envir Parizadeh, Leila Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
topic_facet |
Huître creuse C. gigas V. aestuarianus Pathogenèse Cycle d'infectieux Virulence bactérienne Régulation de l’expression des gènes Cupped oysters Pathogenesis Infectious cycle Bacterial virulence Regulation of gene expression geo envir |
description |
Oyster-farming in France is mainly based on pacific cupped oysters, Crassostrea gigas culture. Currently, oyster culture is confronted by several abnormal episodes of mass mortality affecting all life stages. These outbeaks involve, among other factors, infectious agents including bacteria of the genus Vibrio. In France, since 2000, V. aestuarianus is known as a bacterium that impacts the survival of C. gigas. Since 2011, its detection frequency in adult oyster mortalities cases reported by REPAMO network (REseau de PAthologie des Mollusques), is constantly increasing. In this context, to study V. aestuarianus disease development in C. gigas, an experimental infection model based on immersion in sea water containing freshly shed bacteria was developed. By monitoring the presence of strain 12/016 (virulent strain) and its mutant 12/016 ΔvarS (non-virulent strain) in the seawater, in the different tissues and in the haemolymph of live and moribund animals, we showed that the infectious cycle consists of several successive phases: I) rapid penetration of the bacterium into the host (less than 24 hours) and initial colonization of the haemolymph and gills, II) 3-4 days of incubation during which the virulent strain multiplies in whole oyster tissues and III) acute mortalities (animal death due to septicemia). At this stage, recruitment and haemocyte lysis as well as different tissue lesions such as lysis of the sub-epithelial connective tissue in the mantle and atrophy of digestive diverticula were observed. On the other hand, relative expression of 18 virulence genes (known in other Vibrion) were analyzed by RT-QPCR. Virulence factors are regulated differently during different stages of infection and vam metalloprotease is significantly over-expressed in the haemolymph of infected animals at day 4 post infection (intermediate stage of infection) compared to its level of expression at day 1 post infection (early stage). L’ostréiculture française repose essentiellement sur l’élevage de l’huître creuse, Crassostrea ... |
author2 |
La Rochelle Travers, Marie-Agnès |
format |
Thesis |
author |
Parizadeh, Leila |
author_facet |
Parizadeh, Leila |
author_sort |
Parizadeh, Leila |
title |
Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
title_short |
Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
title_full |
Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
title_fullStr |
Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
title_full_unstemmed |
Pathogenesis of Vibrio aestuarianus, a bacterium affecting the Pacific oyster Crassostrea gigas |
title_sort |
pathogenesis of vibrio aestuarianus, a bacterium affecting the pacific oyster crassostrea gigas |
publishDate |
2018 |
url |
http://www.theses.fr/2018LAROS027 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Crassostrea gigas Pacific oyster |
genre_facet |
Crassostrea gigas Pacific oyster |
op_source |
Theses.fr |
op_relation |
10670/1.7lg16g http://www.theses.fr/2018LAROS027 |
op_rights |
other |
_version_ |
1766393771885330432 |