research

1. Marine microbiomesAll environments on Earth have distinct communities of microorganisms, or “microbiomes,” that are integral to ecosystem function. Microbiomes regulate processes like nutrient cycling and the health of higher organisms, and often contain thousands of different species. The ocean is home to many different microbiomes, including those in the water column and sediments, and attached to particles or animals. However, most microbes have yet to be cultured in a laboratory. Instead, we rely on DNA and RNA sequencing to answer basic questions about who is present and what their functional roles are. Large-scale sequence data analysis is also commonly referred to as “-omics” in reference to terms like genomics, metagenomics, and transcriptomics, which are the analysis of whole genomes, environmental DNA, and gene expression, respectively. As a postdoc at Georgia Tech, I am applying bioinformatic tools to marine and aquarium systems to understand how communities are shaped by competition, respond to perturbations, and impact the health of their environment.

Field work in the Bahamas, 2013.

2. Microbial chemical ecology​Bacteria produce small chemical compounds with a wide range of bioactivities, including antibiotic and anticancer properties. These compounds, also known as “secondary metabolites” or “natural products,” have been studied for decades as an avenue for drug discovery. I am interested in their ecological roles - why bacteria produce them in nature. My Ph.D. work focused on the chemical ecology of marine sediment-inhabiting bacteria called Actinomycetes, which are particularly "talented" with their chemistry. Actinomycetes make a huge range of antibiotics, many of which, such as streptomycin and erythromycin, are used in the clinic. I studied three species that are differentiated in part by their "secondary metabolome," or chemical repertoire. Understanding why and how microbes produce these small molecules has important implications for drug discovery, preventing antibiotic resistance, and understanding the fundamentals fundamentals of microbial ecology and evolution.

​3. Host-associated symbiontsAll animals, from ants to humans, have internal and external microbiomes that play important roles in regulating host health. Insects are among the most well-studied host-microbiome systems, and the human microbiome is an active area of research because of linkages between the gut microbiome and diseases. Marine invertebrate microbiomes, in contrast, are poorly understood. At Georgia Tech, I am studying how the gut microbiome of the tropical crab Caphyra rotundifrons helps it process toxic molecules found in its preferred food, the alga Chlorodesmis fastigiata. I am also examining the microbiome of the bryozoan Bugula neritina for evidence of symbiotic production of anti-cancer molecules called bryostatins. The role of symbiotic bacteria in producing, processing, or ​degrading bioactive compounds is an exciting new field in microbial chemical ecology and the marine invertebrates are ideal systems for discovery in these areas.

The tropical crab Caphyra rotundifrons spends most of its life in a tuft of the alga Chlorodesmis fastigiata, which contains toxic chemicals that deter most herbivores. It is thought that the C. rotundifrons diet consists almost exclusively of C. fastigiata, suggesting that the crab gut is specially adapted to detoxify or process the deterrent compounds. I am currently studying the microbiome of both partners in this mutualism to better understand the role of microbes in facilitating the crab's tolerance to the alga. The field component of this research was conducted in Mo'orea, French Polynesia.