Research Interests

Microbial community structure and function

In the Angenent Lab, I am working on quantifying the relationships between microbial communities, their environment, and their function. Some interesting questions include: (1) What aspects of microbial community structure can be predicted by environmental parameters, and vice-versa, what can we infer about the function of a community by measuring its structure? (2) How do community dynamics and population dynamics differ between different systems? How do dynamics and stochasticity differ among different taxonomical divisions or trophic functions? (3) In addition to genotyping a community (measuring its gene content), how can the environmental conditions and phylogenetic structure influence phenotype (the content of enzymes and other proteins)? Finding answers to these questions may ultimately allow us to engineer novel bioenergy technologies, develop environmental remediation strategies, and understand the interaction between pollutants, land use, climate change, and the microbial communities that form the foundation of natural ecosystems.

My research approach focuses on the use of next-generation sequencing along with LC-MS/MS to measure phylogenetic structure, metagenomic content, and the abundance of specific peptides to quantify microbial dynamics in natural and engineered systems. These interdisciplinary, integrative objectives require developing a number of applications and drawing new connections among the fields of bioinformatics, analytical chemistry and computational ecology. The experimental systems I am currently working with are anaerobic bioreactors that produce methane (natural gas) from organic wastes.

Pharmaceutically-active contaminants in the environment

My dissertation research was on the fate of pharmaceutical pollutants in environmental systems, focused mainly on the mechanisms and kinetics of photochemical reactions (reactions initiated by the absorption of sunlight). I am still particularly interested in the fate of antibiotics and antimicrobial compounds, and the effects these compounds and their degradation products have on microbial ecology and the selection for resistance genes in the environment.

Publications

Werner, J. J.; Ptak, A. C.; Rahm, B. G.; Zhang, S.; Richardson, R. E., 2009. Absolute quantification of Dehalococcoides proteins: Enzyme bioindicators of chlorinated ethene dehalorespiration. In Press, Environmental Microbiology.

Werner, J. J.; McNeill, K.; Arnold, W. A., 2009. Photolysis of chlortetracycline on a clay surface. Journal of Agricultural & Food Chemistry (ASAP).

Werner, J. J.; Chintapalli, M.; Ludeen, R. A.; Wammer, K. H.; McNeill, K.; Arnold, W. A., 2007. Environmental photochemistry of tylosin: efficient, reversible photoisomerization to a less-active isomer followed by photolysis. Jounal of Agricultural & Food Chemistry 55:7062-7068. [link]

Werner, J. J.; Arnold, W. A.; McNeill, K., 2006. Water hardness as a photochemical parameter: photolysis of tetracycline as a function of calcium concentration, magnesium concentration and pH. Environmental Science & Technology 40:7236-7241 (Special Issue on Emerging Contaminants). [link]

Werner, J. J.; McNeill, K.; Arnold, W. A., 2005. Environmental photodegradation of mefenamic acid. Chemosphere 58: 1339-1346. [link]

Packer, J. L.; Werner, J. J.; Latch, D. E.; McNeill, K.; Arnold, W. A., 2003. Photochemical fate of pharmaceuticals in the environment: Naproxen, diclofenac, clofibric acid, and ibuprofen. Aquatic Sciences 64:342-351 (Special Issue on Photochemical Processes in the Hydrosphere). [link]