Our lab studies the ecology of microorganisms that are of significance to public health. Because only a fraction of environmentally derived organisms can be grown in the laboratory, science is limited to a rudimentary understanding of the basic chemical, physical and biological principles governing their abundance, diversity and metabolic activities in nature.
We design and use molecular probes to detect organisms in situ, circumventing the need for laboratory cultivation. Because these techniques are based on genotypic traits, they are a much more accurate means of identifying organisms than are classical methods, based on phenotypic analysis.
One area of current interest is the development of a reliable method to track sources of fecal pollution in watersheds. A PCR-based detection method is being validated for use in discriminating bacteria that are of human or ruminant origin. In conjunction with these studies, we are examining the ability of different detection methods, both classical and molecular, to predict the presence of the pathogenic protozoan Cryptosporidium in source waters.
Another area of current research examines environmental factors governing the production of the hepatotoxin, microcystin, by Microcystis aeruginosa. Field studies have included PCR-based methods designed to forecast cyanobacterial blooms in the Hudson River Estuary and the effect of light intensity on the transcription of a toxin-specific gene. Proposed studies involve the development of a fluorescence-based immunolocalization procedure for microcystin, which will permit in situ identification of toxin-containing cyanobacterial cells, thereby facilitating an understanding of ecological variables influencing its production.