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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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Related in: MedlinePlus

Growth media influences biofilm disassembly.Confocal micrographs of S. aureus SH1000 biofilms grown in TSBg media (A) for 30 hours readily disassemble upon exposure to biofilm matrix degrading enzymes proteinase K, dispersin B, and DNaseI at 0.2 µg/mL each. S. aureus biofilms grown in PNG media (B) for 30 hours fail to disassemble upon exposure to matrix-degrading enzymes. Images are representative of three separate experiments and each side of a grid square represents 20 µm. (C) Biofilms at the air-liquid interface of test tube cultures withstand 1% SDS exposure when grown in PNG media but disassemble when grown in TSBg. Top images show stained test tube biofilms; graph below is quantification of biofilm biomass. * P<0.002 compared to no SDS treatment.
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ppat-1002744-g001: Growth media influences biofilm disassembly.Confocal micrographs of S. aureus SH1000 biofilms grown in TSBg media (A) for 30 hours readily disassemble upon exposure to biofilm matrix degrading enzymes proteinase K, dispersin B, and DNaseI at 0.2 µg/mL each. S. aureus biofilms grown in PNG media (B) for 30 hours fail to disassemble upon exposure to matrix-degrading enzymes. Images are representative of three separate experiments and each side of a grid square represents 20 µm. (C) Biofilms at the air-liquid interface of test tube cultures withstand 1% SDS exposure when grown in PNG media but disassemble when grown in TSBg. Top images show stained test tube biofilms; graph below is quantification of biofilm biomass. * P<0.002 compared to no SDS treatment.

Mentions: Biofilms that persist in the human body are often resistant to conventional antimicrobial treatment prior to dispersal. To gain insight into how the S. aureus biofilm matrix affects disassembly under different growth conditions, we grew S. aureus flow cell biofilms with various lab media. Next we used enzymes known to target primary matrix components in order to test biofilm resistance (Fig. 1A & 1B). These enzymes include proteinase K (protein), DNaseI (DNA), and dispersin B (polysaccharide). By using a variety of degradative enzymes, we expected to observe complete biofilm eradication. Biofilms grown in tryptic soy broth supplemented with glucose (TSBg) rapidly disassembled after enzymatic treatment (Fig. 1A). However, biofilms grown in peptone-NaCl-glucose (PNG) media did not disassemble after the same enzymatic treatment (Fig. 1B).


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

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

Growth media influences biofilm disassembly.Confocal micrographs of S. aureus SH1000 biofilms grown in TSBg media (A) for 30 hours readily disassemble upon exposure to biofilm matrix degrading enzymes proteinase K, dispersin B, and DNaseI at 0.2 µg/mL each. S. aureus biofilms grown in PNG media (B) for 30 hours fail to disassemble upon exposure to matrix-degrading enzymes. Images are representative of three separate experiments and each side of a grid square represents 20 µm. (C) Biofilms at the air-liquid interface of test tube cultures withstand 1% SDS exposure when grown in PNG media but disassemble when grown in TSBg. Top images show stained test tube biofilms; graph below is quantification of biofilm biomass. * P<0.002 compared to no SDS treatment.
© Copyright Policy
Related In: Results  -  Collection

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

ppat-1002744-g001: Growth media influences biofilm disassembly.Confocal micrographs of S. aureus SH1000 biofilms grown in TSBg media (A) for 30 hours readily disassemble upon exposure to biofilm matrix degrading enzymes proteinase K, dispersin B, and DNaseI at 0.2 µg/mL each. S. aureus biofilms grown in PNG media (B) for 30 hours fail to disassemble upon exposure to matrix-degrading enzymes. Images are representative of three separate experiments and each side of a grid square represents 20 µm. (C) Biofilms at the air-liquid interface of test tube cultures withstand 1% SDS exposure when grown in PNG media but disassemble when grown in TSBg. Top images show stained test tube biofilms; graph below is quantification of biofilm biomass. * P<0.002 compared to no SDS treatment.
Mentions: Biofilms that persist in the human body are often resistant to conventional antimicrobial treatment prior to dispersal. To gain insight into how the S. aureus biofilm matrix affects disassembly under different growth conditions, we grew S. aureus flow cell biofilms with various lab media. Next we used enzymes known to target primary matrix components in order to test biofilm resistance (Fig. 1A & 1B). These enzymes include proteinase K (protein), DNaseI (DNA), and dispersin B (polysaccharide). By using a variety of degradative enzymes, we expected to observe complete biofilm eradication. Biofilms grown in tryptic soy broth supplemented with glucose (TSBg) rapidly disassembled after enzymatic treatment (Fig. 1A). However, biofilms grown in peptone-NaCl-glucose (PNG) media did not disassemble after the same enzymatic treatment (Fig. 1B).

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