In the coming years, our goal is to understand how motile microbes, such as P. aeruginosa, regulate the transition to a biofilm lifestyle. A key aspect of this transition is the regulation (perhaps ?modulation? is a better word) of the three surface behaviors of this microbe: flagellar mediated swarming, TFP-mediated twitching motility and EPS-dependent biofilm formation. The experiments proposed below seek to understand the mechanism(s) underlying the coordination of these surface behaviors. An integral aspect of this work is defining how this microbe detects surface engagement; our work on PilY1 is allowing us to dissect one such ?surface sensing? pathway. My group has already made contributions to this exciting area of microbiology, and we will continue to do so in the come funding period by (i) completing studies proposed in the original application and (ii) breaking open new areas of research. To address the latter, I propose to incorporate a new formal and funded collaboration into years 6?10 of the project with Dr. Gerard Wong at UCLA. We have already co-published five papers with a 6th paper in press at PNAS. We propose the following studies to continue to test the central hypothesis that cdG levels are up-regulated in response to cell-to-substratum contact, leading to reduced motility and promotion of biofilm formation.
Aim 1. Test the hypothesis that a protein-protein interaction cascade signals from PilY1 to SadC to modulate c-di-GMP levels.
Aim 2. Test the hypothesis that SadC coordinates swarming and twitching motility via inner membrane complexes.
Aim 3. Test the hypothesis that stator swapping drives distinct behaviors during early attachment.
Aim 4. Test the hypothesis that modulation of flagellar- and TFP-mediated motility contributes to the formation of polymicrobial communities.
Aim 5. Test the hypothesis that c-di-GMP signaling is required to maintain mature biofilms.

Public Health Relevance

Bacterial biofilm-based infections are estimated to cause upwards of a billion dollars annually in increased medical costs. The work we propose here will reveal mechanisms whereby these communities form, and thus provide insight into how to prevent such infections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI083256-12
Application #
9955169
Study Section
Special Emphasis Panel (NSS)
Program Officer
Lu, Kristina
Project Start
2019-08-01
Project End
2024-07-31
Budget Start
2020-08-01
Budget End
2021-07-31
Support Year
12
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755
Lee, Calvin K; de Anda, Jaime; Baker, Amy E et al. (2018) Multigenerational memory and adaptive adhesion in early bacterial biofilm communities. Proc Natl Acad Sci U S A 115:4471-4476
O'Toole, George A (2018) Cystic Fibrosis Airway Microbiome: Overturning the Old, Opening the Way for the New. J Bacteriol 200:
Limoli, Dominique H; Whitfield, Gregory B; Kitao, Tomoe et al. (2017) Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection. MBio 8:
de Anda, Jaime; Lee, Ernest Y; Lee, Calvin K et al. (2017) High-Speed ""4D"" Computational Microscopy of Bacterial Surface Motility. ACS Nano 11:9340-9351
Ribbe, Jan; Baker, Amy E; Euler, Sebastian et al. (2017) Role of Cyclic Di-GMP and Exopolysaccharide in Type IV Pilus Dynamics. J Bacteriol 199:
Orazi, Giulia; O'Toole, George A (2017) Pseudomonas aeruginosa Alters Staphylococcus aureus Sensitivity to Vancomycin in a Biofilm Model of Cystic Fibrosis Infection. MBio 8:
Bernier, Steve P; Hum, Courtney; Li, Xiang et al. (2017) Pseudomonas aeruginosa-Derived Rhamnolipids and Other Detergents Modulate Colony Morphotype and Motility in the Burkholderia cepacia Complex. J Bacteriol 199:
Baker, Amy E; O'Toole, George A (2017) Bacteria, Rev Your Engines: Stator Dynamics Regulate Flagellar Motility. J Bacteriol 199:
Armitage, Judith P; Becker, Anke; Christie, Peter J et al. (2017) Classic Spotlights: Selected Highlights from the First 100 Years of the Journal of Bacteriology. J Bacteriol 199:
O'Toole, George A (2017) Special Meeting Sections for the ASM Conference on Mechanisms of Interbacterial Cooperation and Competition. J Bacteriol 199:

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