BIOQUIMICA MATTHEWS PDF

Biofilms are communities of bacteria that grow encased in an extracellular matrix that often contains proteins. The spatial organization and the molecular interactions between matrix scaffold proteins remain in most cases largely unknown. Here, we report that Bap protein of Staphylococcus aureus self-assembles into functional amyloid aggregates to build the biofilm matrix in response to environmental conditions. Specifically, Bap is processed and fragments containing at least the N-terminus of the protein become aggregation-prone and self-assemble into amyloid-like structures under acidic pHs and low concentrations of calcium. The molten globule-like state of Bap fragments is stabilized upon binding of the cation, hindering its self-assembly into amyloid fibers. These findings define a dual function for Bap, first as a sensor and then as a scaffold protein to promote biofilm development under specific environmental conditions.

Author:Gardanos Tojagore
Country:Dominican Republic
Language:English (Spanish)
Genre:Business
Published (Last):19 February 2015
Pages:110
PDF File Size:7.78 Mb
ePub File Size:4.59 Mb
ISBN:836-6-60768-734-2
Downloads:21009
Price:Free* [*Free Regsitration Required]
Uploader:Arashirr



Biofilms are communities of bacteria that grow encased in an extracellular matrix that often contains proteins. The spatial organization and the molecular interactions between matrix scaffold proteins remain in most cases largely unknown. Here, we report that Bap protein of Staphylococcus aureus self-assembles into functional amyloid aggregates to build the biofilm matrix in response to environmental conditions.

Specifically, Bap is processed and fragments containing at least the N-terminus of the protein become aggregation-prone and self-assemble into amyloid-like structures under acidic pHs and low concentrations of calcium. The molten globule-like state of Bap fragments is stabilized upon binding of the cation, hindering its self-assembly into amyloid fibers.

These findings define a dual function for Bap, first as a sensor and then as a scaffold protein to promote biofilm development under specific environmental conditions. Since the pH-driven multicellular behavior mediated by Bap occurs in coagulase-negative staphylococci and many other bacteria exploit Bap-like proteins to build a biofilm matrix, the mechanism of amyloid-like aggregation described here may be widespread among pathogenic bacteria.

The authors have declared that no competing interests exist. Fig Summary illustrating the effect of pH and calcium in Bap-mediated multicellular behavior. This site needs JavaScript to work properly. Please enable it to take advantage of the complete set of features! Clipboard, Search History, and several other advanced features are temporarily unavailable. Search: Search. Advanced Clipboard. Create file Cancel. Email citation To:. Format: Summary Summary text Abstract Abstract text. Send email Cancel.

Add to Collections Create a new collection Add to an existing collection. Name your collection: Name must be less than characters. Choose a collection: Unable to load your collection due to an error Please try again. Add Cancel. Add to My Bibliography My Bibliography. Unable to load your delegates due to an error Please try again. Your saved search Name of saved search:. Search terms:. Test search terms. Would you like email updates of new search results? Email: change. Frequency: Monthly Weekly Daily.

Which day? Send at most: 1 item 5 items 10 items 20 items 50 items items items. Send even when there aren't any new results. Optional text in email:. Save Cancel. Create a file for external citation management software Create file Cancel. Full-text links Cite Favorites. Abstract Biofilms are communities of bacteria that grow encased in an extracellular matrix that often contains proteins. Conflict of interest statement The authors have declared that no competing interests exist.

Figures Fig 1. Culture pH determines Bap-mediated aggregation. Fig 1. Cell wall extracts taken at different points of the growth curve from S. Bap-related insoluble aggregates are indicated by a red arrow.

B Growth curve of S. D Bacterial clumping and biofilm formation of S. For bacterial clumping upper panel , bacteria were culture overnight with agitation rpm.

For biofilm formation, S. Cell clumps and biofilm formation from 3 independent experiments were quantified S1A Fig. Fig 2. Proteolytic cleavage of Bap protein….

Proteolytic cleavage of Bap protein allows the formation of Bap-aggregates. A Structural organization of Bap. Green lines correspond to peptides obtained by the MS analysis of the Bap-related insoluble aggregates.

B Summary of the peptides corresponding mostly to the N-terminal region of Bap as identified by MS analysis. Amino acid sequences and positions of identified peptides are shown. C Insoluble material retained in the native gel pocket that was subjected to MS analysis. D Cell wall extracts from S. Fig 3. Region B of Bap is….

Region B of Bap is sufficient to promote biofilm development. A Structural organization of Bap chimeric proteins. S, signal peptide; A, region A; B, region B. C Biofilm formation in microtiter plates under static conditions. D Biofilm formed on glass slides under flow culture conditions using microfermentors. E Bacterial clumping of S. G Bacterial clumping of S. For assays performed with S.

Cell clumps and biofilm from 3 independent experiments were quantified S1B Fig. Fig 4. B Bacterial clumping of S. Table shows the diffusion coefficient D of each population and its corresponding radius R. Pd polydispersity percentage of the corresponding detected population. Fig 5. Percentage of each secondary structure is detailed in the table. B Increase in ThT fluorescence emission upon binding to 0. Free ThT emission spectrum is represented in solid line. C Shift in CR absorbance spectrum upon binding to 0.

Free CR absorbance spectrum is represented in solid line. D Increase in ProteoStat fluorescence emission upon binding to 0. Free Proteostat emission spectrum is represented in solid line. Fig 6. Bap forms amyloid-like fibers.

Protein was incubated 24 h in phosphate-citrate buffer pH 4. D Electron micrographs of S. E Electron micrographs of negatively stained S. G Immunogold labeled samples from S. Fibers are shown at higher magnification in F and H. Fig 7. Biological relevance of Bap amyloids. A Effect of Bap fibers in S. Adhesion of S. Bacterial adhesion was determined after 1 hour of infection. B In vivo biofilm formation of S. Catheters were infected with equal numbers of the strains, and bacteria were recovered from implanted catheters and counted after 4 or 10 days post-infection.

Statistical analysis was performed using the Mann—Whitney test. Fig 8. A Bacterial clumping of S.

KRFTIGUNGSBUNGEN LWS PDF

ISBN 13: 9788490353929

The system can't perform the operation now. Try again later. Citations per year. Duplicate citations. The following articles are merged in Scholar. Their combined citations are counted only for the first article.

CUERPO POETICO JACQUES LECOQ PDF

Nutrition in Health and Disease 11ª Ed.

.

Related Articles