Project description:The synthesis of complex sugars is a key aspect of microbial biology. Cyclic β-1,2-glucan (CβG) is a circular polysaccharide critical for host interactions of many bacteria, including major pathogens of humans (Brucella) and plants (Agrobacterium). CβG is produced by the cyclic glucan synthase (Cgs), a multi-domain membrane protein. So far, its structure as well as the mechanism underlining the synthesis have not been clarified. Here we use cryo-electron microscopy (cryo-EM) and functional approaches to study Cgs from A. tumefaciens. We determine the structure of this complex protein machinery and clarify key aspects of CβG synthesis, revealing a distinct mechanism that uses a tyrosine-linked oligosaccharide intermediate in cycles of polymerization and processing of the glucan chain. Our research opens possibilities for combating pathogens that rely on polysaccharide virulence factors and may lead to synthetic biology approaches for producing complex cyclic sugars.
Project description:Analysis of transcriptional profiles in mDC sorted from apheresed PBMC and stimulated for 6 hours with cyclic glucan or LPS. The hypothesis tested is that cyclic glucan induces maturation and T cell-activation transcripts in human mDC. Total RNA extracted from mDC sorted from apheresed PBMC and activated for 6 hours with cyclic glucan or LPS.
Project description:Analysis of transcriptional profiles in mDC sorted from apheresed PBMC and stimulated for 6 hours with cyclic glucan or LPS. The hypothesis tested is that cyclic glucan induces maturation and T cell-activation transcripts in human mDC.
Project description:We established a bacteria infective intestinal inflammation in turbot (Scophthalmus maximus). And found that β-glucan could significantly alleviate the phenotype of turbot intestinal inflammation. We performed single cell transcriptome analysis to study bacteria infective intestinal inflammation and the effects of β-glucan. Furthermore, we revealed that β-glucan through activates Th17 cells to alleviate intestinal inflammation in turbot.
Project description:Bacterial exopolysaccharide (EPS) formation is crucial for biofilm formation, protection against environmental factors or as storage compounds. EPSs produced by lactic acid bacteria (LAB) are appropriate for applications in food fermentation or the pharmaceutical industry, yet the dynam-ics of formation and degradation thereof are rather poorly described. This study focuses on car-bohydrate active enzymes, including glycosyl transferases (GT) and glycoside hydrolases (GH), and their roles in the formation and potential degradation of O2-substituted (1,3)-β-D-glucan of Levilactobacillus (L.) brevis TMW 1.2112. The fermentation broth of L. brevis TMW 1.2112 was ana-lyzed for changes in viscosity, β-glucan and D-glucose concentrations during exponential, sta-tionary and early death phase. While the viscosity reached its maximum during stationary phase and subsequently decreased, the β-glucan concentration only increased to a plateau. Results were correlated with secretome and proteome data to identify involved enzymes and pathways. The suggested pathway for β-glucan biosynthesis involved a β-1,3 glucan synthase (GT2) and en-zymes from maltose phosphorylase (MP) operons. The decreased viscosity appeared to be associ-ated with cell lysis as the β-glucan concentration did not decrease most likely due to missing ex-tracellular carbohydrate active enzymes. In addition, an operon was discovered containing known moonlighting genes, all of which were detected in both proteome and secretome samples.
Project description:To evaluate the DC genome-wide gene expression in response to beta-glucan and its regulation by IL-1 receptor antagonist (IL-1RA) we used a whole genome microarray. The gene expression profiling was performed in DC left untreated or exposed to beta-glucan for 4 and 12 h, in absence or presence of IL-1RA. This strategy allowed the identification of early/immediate and late/secondary genes regulated by beta-glucan in an IL-1-dependent and -independent manner. Human monocyte-derived DC were obtained by a 6/7-d cultures of freshly isolated monocytes with recombinant human IL-4 (10 ng/ml) and GM-CSF (50 ng/ml). Beta-glucan-associated gene expression and its regulation by IL-1RA in human DC was measured in cells left untreated or at 4 and 12 h after exposure to 10 ug/ml of particulate beta-glucan in absence or presence of 2.5 ug/ml of IL-1RA. Five different conditions (Untreated 0h, beta-glucan 4h, IL-1RA + beta-glucan 4h, beta-glucan 12h, and IL-1RA + beta-glucan 12h) were tested using DC from three different donors.
Project description:The goal of this study was to define the impact of beta-glucan (CLEC7A agonist), anti-CD40 (agonist) and the combination of beta-glucan and anti-CD40 on the intra-tumoral immune landscape of mouse orthotopic pancreatic tumors using single-cell RNA sequencing.
Project description:beta-glucan induced glycolysis in HIF-1 depedent manner. We reported that beta-glucan injection in mice led to upregulated glycolysis. HIF-1a plays a major role in this process. Mice receives beta-glucan via ip for 4 days. Splenocytes were isolated for RNA sequencing.
Project description:Induction of trained immunity by beta-glucan affects myeloid cells and their bone marrow progenitors. In particular, broad epigenetic alterations in trained myeloid cells have been demonstrated. In this study, we performed single cell ATAC sequencing in GMP and neutrophils from beta-glucan treated mice, as compared to control-treated mice, in order to investigate the impact of trained immunity on the epigenetic profile of GMP and neutrophils.
Project description:We found that beta-glucan treatment induces early induction of transcripts associated with inflammation and metabolism. Several days after beta-glucan treatment, genes associated with differentation and housekeeping remain upregulated. LPS treatment induces a strong inflammatory response. Beta-glucan did not significantly alter the macrophage response to LPS.