Project description:To understand the molecular mechanisms induced by deoxycholate (DCA) during biofilm formation and to identify factors implicated in the strong density of biofilms in this condition, we performed a transcriptomic analysis using microarrays. The microarrays were used to compare C. difficile transcription profiles of a 48 h biofilm (in BHISG medium) treated with DCA with an untreated biofilm.
Project description:The objective of our study was to characterize the response of C. difficle to deoxycholate. When C. difficile was grown in the presence of deoxycholate, we observed an increase in biofilm formation. We then analyzed the transcriptome of the DCA-induced biofilm and cells grown in the absence of deoxycholate. The transcriptome analysis was then confirmed using phenotypic assays and gene-deletion strains.
Project description:The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesised that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is still poorly understood. It has been shown that specific molecules such as deoxycholate (DCA) or metronidazole induce biofilm formation, but the mechanisms involved remain elusive. In this study, we describe the role of the lipoprotein CD1687 in the DCA-induced biofilm formation of C. difficile. We showed that the expression of CD1687, which is part of an operon within the CD1685-CD1689 gene cluster, is controlled by multiple transcription starting sites induced for some of them in response to DCA. Only CD1687 is required for biofilm formation and the overexpression of CD1687 is sufficient to induce biofilm formation. Using RNAseq analysis, we showed that CD1687 affects the expression of transporters and metabolic pathways and we identified several potential binding partners by pull-down assay, including transport-associated extracellular proteins. We then demonstrated that CD1687 is surface exposed in C. difficile, and this localization is required for DCA-induced biofilm formation. Given this localization and that C. difficile forms eDNA-rich biofilms, we confirmed that CD1687 binds DNA in a non-specific manner. We thus hypothesize that CD1687 is a component of the downstream response to DCA leading to biofilm formation by promoting interaction between the cells and the biofilm matrix by binding eDNA.
Project description:we report that succinate, a metabolite abundantly produced by the dysbiotic gut microbiota, induces in vitro biofilm formation of C. difficile strains. We characterized the morphology and spatial composition of succinate- induced biofilms, and compared to non-induced or deoxycholate-induced biofilms, biofilms induced by succinate are significantly thicker, structurally more complex, and poorer in proteins and exopolysaccharides (EPS).
Project description:Transcriptional analysis of Clostridium difficile R20291 in biofilm formation, planktonic state and grown on blood agar RNA sequencing was performed on Clostridium difficile R20291 in three different conditions: Biofilm formation, plantonic state and grown on blood agar plates. Each condtion has 3 replicates.
Project description:The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesised that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is still poorly understood. It has been shown that specific molecules such as deoxycholate (DCA) or metronidazole induce biofilm formation, but the mechanisms involved remain elusive. In this study, we describe the role of the lipoprotein CD1687 in the DCA-induced biofilm formation of C. difficile. We showed that the expression of CD1687, which is part of an operon within the CD1685-CD1689 gene cluster, is controlled by multiple transcription starting sites induced for some of them in response to DCA. Only CD1687 is required for biofilm formation and the overexpression of CD1687 is sufficient to induce biofilm formation. Using RNAseq analysis, we showed that CD1687 affects the expression of transporters and metabolic pathways and we identified several potential binding partners by pull-down assay, including transport-associated extracellular proteins. We then demonstrated that CD1687 is surface exposed in C. difficile, and this localization is required for DCA-induced biofilm formation. Given this localization and that C. difficile forms eDNA-rich biofilms, we confirmed that CD1687 binds DNA in a non-specific manner. We thus hypothesize that CD1687 is a component of the downstream response to DCA leading to biofilm formation by promoting interaction between the cells and the biofilm matrix by binding eDNA.
Project description:Candida species are components of the normal intestinal microbiota and are under constant exposure to bacterial metabolites, including secondary bile salts. Here, we examined the effect of a secondary bile salt, sodium deoxycholate (NaDCA), on the formation of biofilms by Candida tropicalis. In contrast to C. albicans, C. tropicalis tended to maintain its absolute biofilm biomass and surface hydrophobicity in the presence of NaDCA. Fluorescent 3D microscopic imaging of the biofilm revealed that NaDCA treatment reduced filamentous projection to the top of the biofilm. RNA-seq analysis revealed that some genes, especially those associated with iron metabolism, were differentially expressed in NaDCA-treated C. tropicalis. Although NaDCA altered the appearance of C. tropicalis biofilms, analysis of the expression of key virulence factor genes encoding agglutinin-like sequences and candidalysin revealed that these genes were less affected by NaDCA in C. tropicalis than in C. albicans. High-iron exposure had a negative effect on C. tropicalis biofilm biomass. These results suggest a difference in the intestinal niche occupied by C. albicans and C. tropicalis according to the local availability of secondary bile salts.