Project description:DNA, RNA and protein were extracted from the culture and subjected to massive parallel sequencing and nano-LC-MS-MS respectively Combination of these methods enabled the reconstruction of the complete genome sequence of M oxyfera from the metagenome and identification of the functionally relevant enzymes and genes
Project description:Catheter-associated urinary tract infections (CAUTI) account for 40% of all nosocomial infections and can lead to significant life-threatening complications such as bacteremia. Microbial biofilms play an important role in the development and pathogenesis of CAUTI, and these biofilms are often polymicrobial. Proteus mirabilis and Enterococcus faecalis are two of the most common causes of CAUTI, and they often persistently co-colonize the catheterized urinary tract. We previously demonstrated that co-culture of E. faecalis with P. mirabilis increased biofilm biomass, antimicrobial resistance, and disease severity. In this study, we uncover the metabolic interplay that drives biofilm enhancement and examine the contribution of this polymicrobial interaction to CAUTI severity. Through compositional and proteomic biofilm analyses, we determined that the increase in biofilm biomass stems from an increase in the protein fraction of the polymicrobial biofilm matrix. We further observed an enrichment in proteins associated with ornithine and arginine metabolism in polymicrobial biofilms compared to single-species biofilms. By testing mutants of E. faecalis and P. mirabilis, we found that L-ornithine secreted by the E. faecalis ArcD antiporter promotes L-arginine biosynthesis in P. mirabilis via ArgF, which ultimately fuels production of proteins that facilitate contact-dependent interactions to enhance biofilm biomass. We further demonstrate that ArcD and ArgF are not important for urinary tract colonization by either species when alone, but ornithine/arginine interplay is critical for the increased disease severity that occurs during coinfection. This study provides deeper insight into the polymicrobial interactions occurring during CAUTI and highlights how these interactions can have significant impacts on pathogenesis and bacterial persistence.
Project description:NF-kB is a transcriptional factor that consists in homo and heterodimers of the large family of Rel subunits. Among the most important functions for NF-kB, initiation of immunological/inflammatory responses and regulation of cell proliferation/apoptosis which are the major features of severe infections. Although the role of NF-kB is crucial in host defense against pathogens, mice deficient for individual subunits of NF-kB have not been explored in murine models of polymicrobial infection. In this report, we have investigated in vivo the consequences of cRel subunit deficiency in the survival to polymicrobial infection. We have also approached the underlying mechanisms of the host defense by analyzing cytokine production, bacterial clearance and the distribution of innate and adaptive immune cells. Absence of cRel enhances mice mortality to polymicrobial sepsis. The decreased survival of cRel-/- animals upon infection is not related to altered local mechanisms of innate defense such as the peritoneal recruitment of the Gr.1+CD11b+ phagocytic cells and the bacterial clearance. However, cRel deficiency allows to altered systemic cytokine response associated to sustained loss of the lymphoïd subset CD8a+ of spleen dendritic cells, key antigen-presenting cells for the initiation of the adaptive immunity. Genome-wide analysis of the systemic host response to polymicrobial sepsis reveals inflammatory/immune and apoptotic gene signatures associated to cRel subunit. In this study we identified the NF-kB member cRel, as a key factor which plays a critical role in survival to polymicrobial sepsis and also as a regulatory transcription subunit controlling the inflammatory and the adaptive immune responses in severe infection.
Project description:In this study we examined an anaerobic digester reactor fed with cellulose in order to identify cellulose degrading microorganisms using a culture independent approach. A metagenome was linked to the newly synthesized proteins involved by cellulose, by investigation of labelled proteins (Protein-SIP). The study aims at identifying microorganisms involved in the degradation of plant-based biomass.
Project description:We systematically assessed the transcriptomic changes of circulating leukocytes from whole blood of mice that had undergone polymicrobial sepsis. We systematically assessed the transcriptomic changes of liver tissue of mice that had undergone polymicrobial sepsis. Data indicate strong dissimilarities in early gene expression during murine sepsis affecting several pathways such as Toll-like receptor signalling, MAPK signalling, cytokine-cytokine receptor interaction, chemokine-signalling, and apoptosis during murine sepsis.
Project description:Metagenome data from soil samples were collected at 0 to 10cm deep from 2 avocado orchards in Channybearup, Western Australia, in 2024. Amplicon sequence variant (ASV) tables were constructed based on the DADA2 pipeline with default parameters.