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Functional amyloids composed of phenol soluble modulins stabilize Staphylococcus aureus biofilms.

Schwartz K, Syed AK, Stephenson RE, Rickard AH, Boles BR - PLoS Pathog. (2012)

Bottom Line: Mutants unable to produce PSMs were susceptible to biofilm disassembly by matrix degrading enzymes and mechanical stress.Previous work has associated PSMs with biofilm disassembly, and we present data showing that soluble PSM peptides disperse biofilms while polymerized peptides do not.This work suggests the PSMs' aggregation into amyloid fibers modulates their biological activity and role in biofilms.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
Staphylococcus aureus is an opportunistic pathogen that colonizes the skin and mucosal surfaces of mammals. Persistent staphylococcal infections often involve surface-associated communities called biofilms. Here we report the discovery of a novel extracellular fibril structure that promotes S. aureus biofilm integrity. Biochemical and genetic analysis has revealed that these fibers have amyloid-like properties and consist of small peptides called phenol soluble modulins (PSMs). Mutants unable to produce PSMs were susceptible to biofilm disassembly by matrix degrading enzymes and mechanical stress. Previous work has associated PSMs with biofilm disassembly, and we present data showing that soluble PSM peptides disperse biofilms while polymerized peptides do not. This work suggests the PSMs' aggregation into amyloid fibers modulates their biological activity and role in biofilms.

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Mutants unable to produce α and βPSMs fail to form fibers during biofilm growth.TEM micrographs of S. aureus biofilm cells grown for five days in PNG media. (A) wildtype (strain SH1000), (B) Δαβpsm (strain BB2388), (C) Δαβpsm complemented (strain BB2408). (D–F) TEM micrographs of fiber preparations from wildtype (D), Δαβpsm (E), and Δαβpsm complemented (F). Bars indicate 500 nm.
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ppat-1002744-g005: Mutants unable to produce α and βPSMs fail to form fibers during biofilm growth.TEM micrographs of S. aureus biofilm cells grown for five days in PNG media. (A) wildtype (strain SH1000), (B) Δαβpsm (strain BB2388), (C) Δαβpsm complemented (strain BB2408). (D–F) TEM micrographs of fiber preparations from wildtype (D), Δαβpsm (E), and Δαβpsm complemented (F). Bars indicate 500 nm.

Mentions: We generated an ΔαβPSM double-knockout mutant and assessed fiber production. TEM analysis of biofilm cells revealed that this mutant did not produce fibers after five days of growth in PNG media (Fig. 5B) compared to the wildtype parent strain grown under the same conditions (Fig. 5A). In addition, fibers could be isolated from wildtype (Fig. 5D) but not mutant biofilms (Fig. 5E). Fiber production was complemented by expression of the αpsm and βpsm operons in trans (Fig. 5C & 5F).


Functional amyloids composed of phenol soluble modulins stabilize Staphylococcus aureus biofilms.

Schwartz K, Syed AK, Stephenson RE, Rickard AH, Boles BR - PLoS Pathog. (2012)

Mutants unable to produce α and βPSMs fail to form fibers during biofilm growth.TEM micrographs of S. aureus biofilm cells grown for five days in PNG media. (A) wildtype (strain SH1000), (B) Δαβpsm (strain BB2388), (C) Δαβpsm complemented (strain BB2408). (D–F) TEM micrographs of fiber preparations from wildtype (D), Δαβpsm (E), and Δαβpsm complemented (F). Bars indicate 500 nm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369951&req=5

ppat-1002744-g005: Mutants unable to produce α and βPSMs fail to form fibers during biofilm growth.TEM micrographs of S. aureus biofilm cells grown for five days in PNG media. (A) wildtype (strain SH1000), (B) Δαβpsm (strain BB2388), (C) Δαβpsm complemented (strain BB2408). (D–F) TEM micrographs of fiber preparations from wildtype (D), Δαβpsm (E), and Δαβpsm complemented (F). Bars indicate 500 nm.
Mentions: We generated an ΔαβPSM double-knockout mutant and assessed fiber production. TEM analysis of biofilm cells revealed that this mutant did not produce fibers after five days of growth in PNG media (Fig. 5B) compared to the wildtype parent strain grown under the same conditions (Fig. 5A). In addition, fibers could be isolated from wildtype (Fig. 5D) but not mutant biofilms (Fig. 5E). Fiber production was complemented by expression of the αpsm and βpsm operons in trans (Fig. 5C & 5F).

Bottom Line: Mutants unable to produce PSMs were susceptible to biofilm disassembly by matrix degrading enzymes and mechanical stress.Previous work has associated PSMs with biofilm disassembly, and we present data showing that soluble PSM peptides disperse biofilms while polymerized peptides do not.This work suggests the PSMs' aggregation into amyloid fibers modulates their biological activity and role in biofilms.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
Staphylococcus aureus is an opportunistic pathogen that colonizes the skin and mucosal surfaces of mammals. Persistent staphylococcal infections often involve surface-associated communities called biofilms. Here we report the discovery of a novel extracellular fibril structure that promotes S. aureus biofilm integrity. Biochemical and genetic analysis has revealed that these fibers have amyloid-like properties and consist of small peptides called phenol soluble modulins (PSMs). Mutants unable to produce PSMs were susceptible to biofilm disassembly by matrix degrading enzymes and mechanical stress. Previous work has associated PSMs with biofilm disassembly, and we present data showing that soluble PSM peptides disperse biofilms while polymerized peptides do not. This work suggests the PSMs' aggregation into amyloid fibers modulates their biological activity and role in biofilms.

Show MeSH
Related in: MedlinePlus