Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.
Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
NPJ Biofilms Microbiomes. 2023 Feb 2;9(1):7. doi: 10.1038/s41522-023-00375-7.
Pel exopolysaccharide biosynthetic loci are phylogenetically widespread biofilm matrix determinants in bacteria. In Pseudomonas aeruginosa, Pel is crucial for cell-to-cell interactions and reducing susceptibility to antibiotic and mucolytic treatments. While genes encoding glycoside hydrolases have long been linked to biofilm exopolysaccharide biosynthesis, their physiological role in biofilm development is unclear. Here we demonstrate that the glycoside hydrolase activity of P. aeruginosa PelA decreases adherent biofilm biomass and is responsible for generating the low molecular weight secreted form of the Pel exopolysaccharide. We show that the generation of secreted Pel contributes to the biomechanical properties of the biofilm and decreases the virulence of P. aeruginosa in Caenorhabditis elegans and Drosophila melanogaster. Our results reveal that glycoside hydrolases found in exopolysaccharide biosynthetic systems can help shape the soft matter attributes of a biofilm and propose that secreted matrix components be referred to as matrix associated to better reflect their influence.
聚酮糖生物合成基因座在细菌中是广泛存在的生物膜基质决定因素。在铜绿假单胞菌中，Pel 对于细胞间相互作用至关重要，并降低了对抗生素和粘液溶解治疗的敏感性。虽然编码糖苷水解酶的基因长期以来一直与生物膜胞外多糖生物合成有关，但它们在生物膜发育中的生理作用尚不清楚。在这里，我们证明了铜绿假单胞菌 PelA 的糖苷水解酶活性降低了附着生物膜的生物量，并负责产生 Pel 胞外多糖的低分子量分泌形式。我们表明，分泌的 Pel 的产生有助于生物膜的生物力学特性，并降低了铜绿假单胞菌在秀丽隐杆线虫和黑腹果蝇中的毒力。我们的结果表明，在胞外多糖生物合成系统中发现的糖苷水解酶可以帮助塑造生物膜的软物质特性，并提出将分泌基质成分称为基质相关物，以更好地反映它们的影响。
