Assembly and Development of the Pseudomonas aeruginosa Biofilm Matrix

PLoS Pathogens

Matthew R. Parsek¹  Daniel J. Wozniak²  Luyan Ma²  Haiping Lu²  Matthew Conover²  Kenneth Bayles³ 

[1] Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America;Microbiology and Immunology, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America;Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America

关键词: Bacterial biofilms;    Pseudomonas aeruginosa;    Cell staining;    Extracellular matrix;    Biofilms;    Lectins;    Cellulases;    Swimming;   

DOI  :  10.1371/journal.ppat.1000354

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Virtually all cells living in multicellular structures such as tissues and organs are encased in an extracellular matrix. One of the most important features of a biofilm is the extracellular polymeric substance that functions as a matrix, holding bacterial cells together. Yet very little is known about how the matrix forms or how matrix components encase bacteria during biofilm development. Pseudomonas aeruginosa forms environmentally and clinically relevant biofilms and is a paradigm organism for the study of biofilms. The extracellular polymeric substance of P. aeruginosa biofilms is an ill-defined mix of polysaccharides, nucleic acids, and proteins. Here, we directly visualize the product of the polysaccharide synthesis locus (Psl exopolysaccharide) at different stages of biofilm development. During attachment, Psl is anchored on the cell surface in a helical pattern. This promotes cell–cell interactions and assembly of a matrix, which holds bacteria in the biofilm and on the surface. Chemical dissociation of Psl from the bacterial surface disrupted the Psl matrix as well as the biofilm structure. During biofilm maturation, Psl accumulates on the periphery of 3-D-structured microcolonies, resulting in a Psl matrix-free cavity in the microcolony center. At the dispersion stage, swimming cells appear in this matrix cavity. Dead cells and extracellular DNA (eDNA) are also concentrated in the Psl matrix-free area. Deletion of genes that control cell death and autolysis affects the formation of the matrix cavity and microcolony dispersion. These data provide a mechanism for how P. aeruginosa builds a matrix and subsequently a cavity to free a portion of cells for seeding dispersal. Direct visualization reveals that Psl is a key scaffolding matrix component and opens up avenues for therapeutics of biofilm-related complications.

【 授权许可】

CC BY