Skip to Main content Skip to Navigation
Theses

Etude comparative des interactions Vibrio - phagocytes dans l'environnement marin

Abstract : Vibrio strains belonging to the Splendidus clade have been repeatedly found in juvenile diseased oysters affected by summer mortalities. V. tasmaniensis LGP32 is an intracellular pathogen of oyster hemocytes which has been reported to alter the oxidative burst and inhibit phagosome maturation.We here focus on the interactions between phagocytes and V. tasmaniensis LGP32, at molecular, cellular and environmental scales. In the first part of this work, we uncover anunknown antimicrobial mechanism of C. gigas hemocytes: the formation of DNA extracellular traps (ETs). These ETs are associated with antimicrobial histones and are able to entrap bacteria. As in vertebrates, ETs formation depends on reactive oxygen species production. In addition, the presence of ETs was confirmed in vivo and has been associated with antimicrobial histones accumulation in tissues, in response to injury or infection. In the second part of this work, we studied the interactions between V. tasmaniensis LGP32 and heterotrophic protists found in the oyster’s environment, such as amoebae and ciliates, which feed on microorganisms by phagocytosis. An important result of this workwas that V. tasmaniensis LGP32 resists to phagocytosis by environmental heterotrophic protists, as well as to oyster hemocytes. To our knowledge, this is the first mechanical description of an interaction between marine amoebae and marine pathogenic bacteria. As the amoebae were isolated from the direct environment of oysters, we can presume that the selective pressure exerted by environmental phagocytes could select for virulence and/or phagocytosis resistance traits in marine bacteria as in the case of V. tasmaniensis LGP32.
Complete list of metadatas

https://hal.archives-ouvertes.fr/tel-01260355
Contributor : Abes Star :  Contact
Submitted on : Tuesday, September 26, 2017 - 10:35:10 AM
Last modification on : Wednesday, May 29, 2019 - 11:40:04 AM

File

POIRIER_2015_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01260355, version 2

Collections

Citation

Aurore Poirier. Etude comparative des interactions Vibrio - phagocytes dans l'environnement marin. Microbiologie et Parasitologie. Université Montpellier, 2015. Français. ⟨NNT : 2015MONTS062⟩. ⟨tel-01260355v2⟩

Share

Metrics

Record views

298

Files downloads

1469