People | Lisa A. Waidner

• Ph.D., Marine Biological Sciences, University of Delaware College of Marine and Earth Studies, 2007.
• M.S., Applied Molecular Biology, University of Maryland Baltimore, 1993.
• B.S., Biological Sciences, University of Maryland Baltimore County, 1991.

Physiology and ecology of phototrophic and photoheterotrophic aquatic bacteria.

Current projects include the investigation of phototrophy in aerobic and anaerobic anoxygenic phototrophs.  

One project focuses on the oxidation of sulfur by the green sulfur bacterium, Chlorobium tepidum, and the effect of sulfur oxidation gene mutations on photosynthetic efficiency.

One goal of this project is to delete genes from the C. tepidum genome that are involved in anaerobic sulfur oxidation.  I have developed a unique pulsed-field gel electrophoresis assay to localize in vitro transposon mutations in the C. tepidum genome.  Subsequent to mutating individual genes, the lab determines phenotypic responses.  The fluorescence profiles of the chlorosomes and inner antenna complexes in intact mutant cells will be studied.  Other phenotypic characterizations will include growth rates, sulfur oxidation, and acetate utilization.

We are also interested in the effect of light on the energy production and organic matter consumption by aerobic anoxygenic phototrophs (AAP).  Since particle-associated bacteria may be responsible for a high proportion of microbial remineralization of organic matter in the seas, the effect of phototrophy in the heterotrophic bacterial community can be important.  We are currently investigating a group of AAP bacteria isolated from seawater of the Delaware Bay.  We hope to determine particle-attachment preferences, pigment production, and light-stimulated uptake of organic matter by these  representative coastal AAP bacteria.

Another aspect of this project is to measure total bacteriochlorophyll a and total AAP bacterial abundances in a series of diel studies at the MOPE observatory sites at the mouth of the Delaware Bay.

1. Rate and fidelity of DNA-binding by bacteriophage T4 gene 32 protein.
2. Phylogenetic and functional diversity of cultured and uncultured hydrothermal vent bacteria.
3. Diversity, abundance, and distribution of aerobic anoxygenic phototrophic bacteria in estuaries.