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Caroline Harwood
Professor of Microbiology

Email: csh5@u.washington.edu
Phone:(206) 221-2848
Office Location: Health Sciences K-335B
Campus Box: 357735






Caroline (Carrie) Harwood received her Ph.D. in microbiology from the University of Massachusetts and completed postdoctoral work at Yale University. She held academic appointments at Cornell University and the University of Iowa before moving to the University of Washington in 2005. Dr. Harwood is an elected member of the National Academy of Sciences, the American Association for the Advancement of Sciences and the American Academy of Microbiology. She received the Procter & Gamble Award in Applied and Environmental Microbiology in 2010.

In my laboratory we are interested in understanding how bacteria integrate diverse environmental signals and diverse metabolic modules to function at the whole cell level. We rely heavily on genome sequencing, mutant construction and analysis and transcriptome analysis for our work.

A major area of interest is in sensory signal transduction and biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa. The lungs of most cystic fibrosis patients become chronically infected with the bacterium P. aeruginosa and this persistent infection causes severe lung damage. P. aeruginosa is damaging to lungs in part because it is able to form biofilms in the environment of the lung. We have been studying a signal transduction complex comprised of six proteins that controls biofilm formation by modulating intracellular levels of a secondary intracellular messenger called cyclic di-GMP. This signal transduction system somehow senses surfaces. We want to know how P. aeruginosa senses surfaces and how it translates this information via c-di-GMP to initiate biofilm formation.

A second area of emphasis involves the metabolically versatile photosynthetic bacterium Rhodopseudomonas palustris also known as Rpal. Rpal is an excellent model organism for studying bacterial mechanisms of long-term survival and also for studying regulation of photosynthesis. It stays alive for periods of months in a starved non-growing state as long as it is provided with light. Our goal is to generate foundational knowledge that will improve our ability to use non-growing photosynthetic bacteria as biocatalysts to convert inexpensive feedstock compounds to hydrogen gas or other biofuels. Towards this end we are trying to understand signal transduction cascades involved in the regulation of photosynthesis at low light. We are also working to define genes that are important for long term survival of non-growing cells.

A final more recent interest, developed in collaboration with E. Peter Greenberg in the Department, is in novel quorum sensing signals for bacterial cell-to-cell communication. We are also exploring signaling between bacteria and the plant Populus.

Selected Publications:

O'Connor, J., N. Kuwada, V. Huangyutitham, P. Wiggins, and C. S. Harwood. 2012. Surface sensing and lateral subcellular localization of WspA, the receptor in a chemosensory-like system leading to c-di-GMP production. Mol. Microbiol. In Press.

Phattasukol, S., M.C. Radey, C. R. Lappala, Y, Oda, H. Hirakawa, M. J. Brittnacher, and C. S. Harwood. 2012. Identification of a p-coumarate degradation regulon in Rhodopseudomonas palustris using Xpression, an integrated tool for prokaryotic RNA-seq data processing. Appl. Environ. Microbiol. In Press

Hirakawa, H., C. S. Harwood, K. B. Pechter, A. L. Schaefer and E. P. Greenberg. 2012. An antisense RNA that affects Rhodopseudomonas palustris quorum-sensing signal receptor expression. Proc. Natl. Acad. Sci. USA. 109:12141-6.

Baraquet, C., K. Murikami, M. R. Parsekj and C. S. Harwood. 2012. The FleQ protein from Pseudomonas aeruginosa functions as both a repressor and an activator to control gene expression from the pel operon promoter in response to c-di-GMP. Nucleic Acids Research. May 11.

Heiniger, E. K., Y. Oda, S. K. Samanta and C. S. Harwood. 2012. How post-translational modification of nitrogenase is circumvented in Rhodopseudomonas palustris strains that produce hydrogen gas constitutively. Applied and Environ. Microbiol.78:1023-32.

Lindmann, A., G. Pessi, A. L. Schaefer, M. E. Mattmann, Q.H. Christensen, A. Kessler, H. Hennecke, H. E. Blackwell, E. P. Greenberg and C. S. Harwood. 2011. Quorum sensing in the soybean root-nodulating bacterium Bradyrhizobium japonicum: identification of isovaleryl-homoserine lactone, an unusual branched-chain signal. Proc. Natl. Acad. Sci. USA. 108:16750-16770.

Ahlgrn, N. S., C. S. Harwood, A. L. Schaefer, E. Griaud, and E. P. Greenberg.. Aryl-homoserine lactone quorum sensing in stem-nodulating photosynthetic bradyrhizobia. Proc. Natl. Acad. Sci. USA. 108:7183-7188.

McKinlay, J. B. and C. S. Harwood. 2010. Carbon dioxide fixation as a central redox cofactor recycling mechanism in bacteria. Proc. Natl. Acad. Sci. USA. 107:11669-11675.

Rey, F.E. and C. S. Harwood. 2010. FixK, a global regulator of microaerobic growth, controls photosynthesis in Rhodopseudomonas palustris. Mol. Microbiol. 75:1007-1020.

Schaefer, A. L., E. P. Greenberg, C. M. Oliver, Y. Oda, J. J. Huang, G. Bittan-Banin, C. M. Peres, S. Schmidt, K. Juhaszova, J.R. Sufrin and C. S. Harwood. 2008. A new class of homoserine lactone quorum-sensing signals. Nature. 454:595-599.

Hickman, J. W. and C. S. Harwood. 2008. Identification of FleQ from Pseudomonas aeruginosa as a c-di-GMP-responsive transcription factor. Mol. Microbiol. 69:376-389.





Department of Microbiology · University of Washington · Box 357735 · Seattle WA 98195-7735

phone: (206) 543-5824 · fax: (206) 543-8297 · micro@u.washington.edu