Functional characterization of VscCD, an important component of the type â
¢ secretion system of Vibrio harveyi.
Microb Pathog
; 157: 104965, 2021 Aug.
Article
em En
| MEDLINE
| ID: mdl-34015493
ABSTRACT
Vibrio harveyi is a Gram-negative bacterium that occurs widely in the ocean and a kind of pathogenic bacteria associated with vibriosis in grouper. We investigated whether the VscCD protein of the type â
¢ secretion system (T3SS) was important for pathogenicity of V. harveyi. Mutations to the vscC and vscD genes (ΔvscCD) and complementation of the ΔvscCD mutant (C-ΔvscCD) were created. Moreover, the biological characteristics of the wild-type (WT) and mutant strains of V. harveyi 345 were compared. The results showed that deletion of the vscCD genes had no effect on bacterial growth, swimming/swarming ability, secretion of extracellular protease, or biofilm formation. However, as compared with the V. harveyi 345 pMMB207 (WT+) and complementary (C-ΔvscCD) strains, the ΔvscCD pMMB207 (ΔvscCD+) mutant displayed decreased resistance to acid stress, H2O2, and antibiotics. In addition, infection of the pearl gentian grouper (âEpinephelus fuscoguttatus × âEpinephelus lanceolatu) showed that as compared with the WT+ and C-ΔvscCD strains, the ΔvscCD+ strain significantly reduced cumulative mortality of the host. The colonization ability of the ΔvscCD+ mutant in the spleen and liver tissues of the pearl gentian grouper was significantly lower than that of the WT+ and C-ΔvscCD strains. In the early stage of infection with the ΔvscCD+ strain, the expression levels of IL-1ß, IL-16, TLR3, TNF-α, MHC-Iα, and CD8α were up-regulated to varying degrees. As compared with the WT+ and C-ΔvscCD strains, luxR expression was significantly up-regulated in the ΔvscCD+ strain, while the expression of vcrH and vp1668 was significantly down-regulated. As an important component of the T3SS, VscCD seemed to play a significant role in the pathogenesis of V. harveyi.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vibrio
/
Vibrioses
/
Doenças dos Peixes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Microb Pathog
Assunto da revista:
DOENCAS TRANSMISSIVEIS
/
MICROBIOLOGIA
Ano de publicação:
2021
Tipo de documento:
Article