Research Interests

My background and broad research interests are in microbial genetics, bioenergetics, metalloprotein cofactor biosynthesis and functional genomics. My research career began investigating chemical inhibition of the proton-translocating NADH:NADP+ transhydrogenase from the photosynthetic bacterium Rhodospirillum rubrum. As a graduate student, my Ph.D. research investigated structure-function relationships in the nitric oxide reductase, a key enzyme of the bacterial nitrogen cycle, from Paracoccus denitrificans. My postdoctoral research then branched out into functional genomics and I was involved in the development and application of two high throughput projects to screen for protein-protein interactions and genetic interactions in the model bacterium Escherichia coli.

My group’s research leverages all of this experience in developing and applying high throughput functional genomics techniques in combination with classical low throughput biochemical and genetic approaches to characterize microbes and specific microbial processes of national importance.

My laboratory’s major research areas are:

• ENIGMA Science Focus Area. As part of ENIGMA the we utilize both functional genomics techniques in combination with biochemical and spectroscopic assays and phenotyping studies to more thoroughly characterize ENIGMA relevant microbes including Pseudomonas fluorescens strains isolated from the Oak Ridge field site and Desulfovibrio vulgaris, sulfate reducing bacteria which play a key role in the biogeochemical sulfur cycle. We are specifically interested in pathways and processes that are key to survival in specific environmental niches and how these organisms cope with naturally encountered stresses such as the the presence of oxygen, heavy metals and competing microbes.
• Iron-sulfur (FeS) cluster biosynthesis. FeS cluster biosynthesis is an evolutionarily conserved process, essential from bacteria to humans. My group has a long standing interest in characterizing novel factors which impact FeS cluster biosynthesis in E. coli, but which do not form part of canonical pathways. We are using genetic and biophysical interaction studies together with FeS enzyme turnover assays to uncover the cellular roles of these factors and the basis for observed epistatic interactions.
• Drosophila microbiome. In collaboration with other Biosciences Area groups we are applying a novel high throughput bacterial mutant fitness profiling assay to study host-microbiota interactions in the Drosophila gut. The fly microbiota represents a simple, tractable microbial community in a well characterized and readily reared host. By manipulating major Drosophila commensals we aim to apply microbial functional genomics tools to identify bacterial genes contributing to both host phenotypes and microbe survival (fitness) in the gut.

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