Harwood, Caroline

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.

One of our goals is to develop the metabolically versatile phototrophic bacterium Rhodopseudomonas palustris as a biocatalyst for the production of hydrogen, a biofuel. We are working to define the metabolic networks that lead to hydrogen generation. The metabolic modules of nitrogen metabolism, photosynthesis, biodegradation and oxygen respiration all contribute to these networks, and we are defining the essential components in each network, how they are regulated, and what the rate limiting steps are in order to be able to effectively predict and maximize bio-hydrogen production. Our second 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 grow 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. Somehow this secondary messenger signals cells to turn on the expression of genes needed for biofilm formation. We want to understand the mechanism of cyclic di-GMP signaling.