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George A. O'Toole, PhD

Professor of Microbiology and Immunology

Microbiology and Immunology

University of Wisconsin - Madison, Ph.D., 1994
Cornell University, B.S., 1988

After postdoctoral work at the University of Wisconsin-Madison and Harvard Medical School, Dr. O'Toole joined the faculty of the Department of Microbiology at Dartmouth Medical School in 1999

Immunology Program
Molecular and Cellular Biology Graduate Programs
Molecular Pathogenesis Program


Contact Information:

Dartmouth Medical School
Vail Building - HB 7550
Hanover NH 03755

Phone: 603-650-1248
Fax: 603-650-1318
Email: George.A.Otoole@Dartmouth.Edu

Professional Interests:

The main focus of the O’Toole laboratory is the study of complex surface-attached bacterial communities known as biofilms. Biofilms can form on a wide variety of surfaces including catheter lines, surgical implants, contact lenses, the lungs of patients with cystic fibrosis, industrial and drinking water pipelines, and on the surfaces of plant roots. In most natural, clinical, and industrial settings bacteria live predominantly in biofilms and not as planktonic (free-swimming) cells such as those typically studied in the laboratory. Bacteria growing in biofilm communities are of great interest to the medical community, because these bacteria become highly resistant to antibiotics by an as yet unknown mechanism. Although much has been learned about the types of microbes that can form biofilms, the morphology of these communities, and their chemical/physical properties, until recently little was known about the molecular genetic basis of biofilm formation or antibiotic resistance.

Studies in the O’Toole lab focus on:
• The molecular genetic basis of biofilm formation.
• The role of the intracellular signaling molecule c-di-GMP in controlling biofilm formation by pseudomonads.
• The signal transduction pathways regulating biofilm formation.
• The mechanisms by which biofilms form on biotic, or living surfaces, and why these biofilms are so highly resistant to antibiotics. We have developed a novel model system for studying biofilms on airway epithelial cells, and these studies are done, in particular, in the context of cystic fibrosis.
• The role of lysogenic phages in impacting biofilm formation.

Recent collaborative studies with Dr. Bruce Stanton’s group here at Dartmouth have explored questions of host-pathogen interactions, using the interplay between the bacterial pathogen Pseudomonas aeruginosa and airway epithelial cells as a model system. We are particularly interested in the role of the toxin, Cif, in altering epithelial cell biology and protein trafficking. We are also studying mechanisms by which P. aeruginosa delivers toxins to host cells.

Please visit the O'Toole Lab Home Page.

Selected Publications:


Cyanide Toxicity to Burkholderia cenocepacia Is Modulated by Polymicrobial Communities and Environmental Factors.
Bernier SP, Workentine ML, Li X, Magarvey NA, O'Toole GA, Surette MG
Front Microbiol. 2016;7:725. doi: 10.3389/fmicb.2016.00725. Epub 2016 May 18.
PMID: 27242743

Classic Spotlight: Cyclic Di-GMP, the Molecule That Makes the Bacterial World Stop Going 'Round.
O'Toole GA
J Bacteriol. 2016 Jun 1;198(11):1553. doi: 10.1128/JB.00190-16. Epub 2016 May 13.
PMID: 27179064

PilZ Domain Protein FlgZ Mediates Cyclic Di-GMP-Dependent Swarming Motility Control in Pseudomonas aeruginosa.
Baker AE, Diepold A, Kuchma SL, Scott JE, Ha DG, Orazi G, Armitage JP, O'Toole GA
J Bacteriol. 2016 Jul 1;198(13):1837-46. doi: 10.1128/JB.00196-16. Epub 2016 Jun 13.
PMID: 27114465

The Inhibitory Site of a Diguanylate Cyclase Is a Necessary Element for Interaction and Signaling with an Effector Protein.
Dahlstrom KM, Giglio KM, Sondermann H, O'Toole GA
J Bacteriol. 2016 Jun 1;198(11):1595-603. doi: 10.1128/JB.00090-16. Epub 2016 May 13.
PMID: 27002135

Sensational biofilms: surface sensing in bacteria.
O'Toole GA, Wong GC
Curr Opin Microbiol. 2016 Apr;30:139-46. doi: 10.1016/j.mib.2016.02.004. Epub 2016 Mar 8.
PMID: 26968016

Friendly Fire: Biological Functions and Consequences of Chromosomal Targeting by CRISPR-Cas Systems.
Heussler GE, O'Toole GA
J Bacteriol. 2016 May 15;198(10):1481-6. doi: 10.1128/JB.00086-16. Epub 2016 Apr 28.
PMID: 26929301

Species-dependent hydrodynamics of flagellum-tethered bacteria in early biofilm development.
Bennett RR, Lee CK, De Anda J, Nealson KH, Yildiz FH, O'Toole GA, Wong GC, Golestanian R
J R Soc Interface. 2016 Feb;13(115):20150966. doi: 10.1098/rsif.2015.0966.
PMID: 26864892

Classic Spotlight: Quorum Sensing and the Multicellular Life of Unicellular Organisms.
O'Toole GA
J Bacteriol. 2016 Feb;198(4):601. doi: 10.1128/JB.00956-15. Epub 2016 Jan 29.
PMID: 26825965

Cystic Fibrosis Lung Infections: Polymicrobial, Complex, and Hard to Treat.
Filkins LM, O'Toole GA
PLoS Pathog. 2015 Dec;11(12):e1005258. doi: 10.1371/journal.ppat.1005258. Epub 2015 Dec 31.
PMID: 26719892

Iron-dependent gene expression in Actinomyces oris.
Mule MP, Giacalone D, Lawlor K, Golden A, Cook C, Lott T, Aksten E, O'Toole GA, Bergeron LJ
J Oral Microbiol. 2015;7:29800. doi: 10.3402/jom.v7.29800. Epub 2015 Dec 16.
PMID: 26685151