Interaction between Bacteroides and HG-type pectins with different molecular weights

Area of Science:

• Microbiome research
• Nutritional science
• Biochemistry

Background:

• Pectins, particularly HG-chains, are abundant polysaccharides.
• Bacteroides species metabolize polysaccharides via polysaccharide utilization loci (PUL).
• The impact of pectin structure on Bacteroides metabolism is not fully understood.

Purpose of the Study:

• To investigate how different molecular weight HG-type pectins affect Bacteroides species.
• To analyze the resulting metabolite profiles and metabolic pathway activation.
• To understand the structure-activity relationship between pectins and gut microbiota.

Main Methods:

• Utilized citrus (CP) and pomelo (PP) pectins of varying molecular weights.
• Identified and cultured specific Bacteroides species (e.g., B. thetaiotaomicron A4, B. caccae K9).
• Employed non-targeted metabolomics, short-chain fatty acids analysis, and transcriptomic studies.

Main Results:

• B. thetaiotaomicron A4 and B. caccae K9 utilized pectins, with propionic acid production affected by pectin molecular weight.
• CP pectin use led to enrichment of carbohydrates, amino acids, peptides, amines, and upregulated sphingolipid and drug metabolism pathways via specific PULs.
• PP pectin use resulted in similar metabolite enrichment and upregulated sphingolipid and pyrimidine metabolism pathways.

Conclusions:

• HG-type pectin molecular weight differentially influences Bacteroides gene expression and metabolic pathways.
• Distinct pectin structures lead to varied metabolite profiles in gut bacteria.
• Findings contribute to understanding pectin-microbiota interactions and inform precision nutrition.