Mostly Microbes and Infection

  Highlights • We have discovered an alternative mechanism mediated by insoluble dietary fiber that contributes to the prevention of colorectal tumorigenesis, potentially accounting for the paradoxical role of SCFAs. • Microbial enzyme encoded by K12373 promotes tumorigenic glycosphingolipid GM3 production, which can be suppressed by high-fiber diet. • As a key node in glycosphingolipid metabolism, K12373 directs metabolic flux primarily towards the GM3 branch and, to a lesser extent, the Gb3 branch, thus illustrating a classic metabolic branch point model in microbiome-host interaction.

  Abstract Porphyromonas gingivalis  is a keystone pathogen in periodontitis, known for its ability to invade gingival epithelial cells and persist intracellularly. Conventional antimicrobials are often ineffective against intracellular pathogens, and natural products remain poorly explored in this context. Here, we investigated the antimicrobial effects of  Boswellia serrata  extract and its bioactive compounds on the dynamics of  P. gingivalis  infection in human gingival epithelial cells. During early times of infection,  B. serrata  extracts stimulated phagocytosis and increased bacterial internalization, suggesting modulation of epithelial uptake mechanisms. At later times of infection,  B. serrata  increased production of reactive oxygen species (ROS) in host cells and markedly reduced intracellular bacterial load. The antimicrobial effect was abolished by the ROS scavenger N-acetylcysteine, confirming a role for oxidative mechanis...

  Highlights • Chickpea oligosaccharides are broadly utilized by gut commensal bacteria. • Algal polysaccharide use is limited to specific Bacteroidota species. • Algae and chickpea fibers enhance short-chain faty acid production. • Transcriptomics reveal coordinated genes for raffinose metabolism.

 Chronic inflammation can be a silent killer, but your diet can play a role in tamping it down.

  Highlights • Avs5 is activated at the early phage infection vesicle • Avs5 hydrolyzes NAD +  to block jumbo phage nucleus formation • Divergent Avs5 clades sense JADA to inhibit jumbo phage infection • JADA is an essential early phage protein with a novel protein fold

  Highlights • Ketogenic diet (KD) alleviates sepsis-induced lung injury via the gut microbiota • KD-enriched lactobacilli produce azelaic acid (AZA) that migrates to sepsis lung • Lung AZA induces MerTK +  macrophages via PPAR-γ toward efferocytosis • AZA associates with improved clinical outcomes in patients with sepsis

  Highlights • Intratumor bacteria promote breast cancer metastatic recurrence in a preclinical model • Cytosolic bacteria induce immune suppressive neutrophils via cGAS-STING-IL-17B • Intra- and extracellular bacteria can play opposite roles in determining neutrophil states • A bacteria invasion signature is associated with poor prognosis in breast cancer patients