MAPLE team members

My job duties are to provide leadership for the Department of Animal Sciences in research and education activities dealing with the roles of microorganisms in animal production systems. Although microorganisms are invisible to the naked eye they have a major impact on the production efficiency, economic viability and environmental compatibility of all animal production systems. For these reasons, our Department has a social responsibility to conduct high quality research that provides new, unbiased, and useful information about the microbiology of food animal production systems. My research activities are funded in these areas by competitively-awarded Federal grants, and I will teach microbiology classes in the Departments of Animal Sciences and Microbiology.

Research in my laboratory concentrates on delineating the mechanisms used by ruminal and other gastrointestinal microorganisms to metabolize proteins and polysaccharides (e.g. starch, cellulose, xylan). Through the use of biochemical, genetic and physiological methods, we have elucidated the means these organisms employ to digest and assimilate these complex polymers and have examined how various species present in these environments interact to form complex food webs that are ultimately responsible for what happens in nature. More recently, my research program has focused on the ecophysiology of animal waste systems; identifying the organisms present, determining their activities in the metabolism of available substrates, and elucidating their role in the production of gaseous emissions (odors). This research employs a combination of conventional microbiological analyses with modern, molecular approaches (i.e. DNA sequence analysis, diagnostic probes) to accomplish this. I also serve as the Research Leader for the Fermentation Biochemistry Research Unit at the National Center for Agricultural Utilization Research (USDA-ARS) which conducts broad-based microbiological research aimed at developing bioproducts and bioprocesses for the conversion of agricultural commodities into biofuels and chemicals, enzymes, and polymers.

My research interests are in the area of ruminal microbiology, with a special emphasis on protozoology and protozoal ecology. I have developed methods for the long-term cultivation of ruminal protozoa, and in collaboration with other scientists, cDNA clones of the genes encoding the small subunit ribosomal RNA's for 8 different species of ruminal protozoa have been obtained. Phylogenetic analyses of these sequences suggest that the ruminal protozoa are monophyletic, that is, all species arise from the same ancestry. In addition to my interests in ruminal protozoology and ecology, I am also conduct studies to isolate and characterize gastrointestinal bacteria and fungi involved with polysaccharide degradation. I also teach a class in ruminal and gastrointestinal microbiology.

My research interests are in the area of ruminal biochemistry and metabolism. I use a combination of continuous culture systems and whole animal studies to examine how the efficiency of microbial protein synthesis is influenced by different feeding regimes. I have used tracer (¹⁵N) technologies to examine nitrogen recycling in the rumen. In the future, I plan to utilize quantitative PCR techniques to study the role of ruminal protozoa in nitrogen turnover in dairy cattle. I am also involved with the teaching of several courses, including "Ruminant Nutrition", "Ruminant Physiology, Nutrition, and Metabolism" and "Advanced Nutrient Utilization I (carbohydrates and fats)".

My research interests are in early intestinal development of poultry and the effects of

early microbial exposure on intestinal maturation in the young turkey poult. This interaction is becoming increasingly important with the current ban on feed grade antibiotics in Europe and the negative perceptions rampant in North America about agricultural uses of antibiotics. I currently teach a graduate-level course in Protein and Amino Acid nutrition.

I am interested in developing fundamental knowledge on the microbial population of swine waste and the swine intestinal tract. This knowledge will be applied towards understanding the relationship between the microbial populations and the production of odorous compounds, and developing improved methods for reducing odor production. Specific objectives are: (1) Identify the major bacterial species of swine manure handling facilities (i.e., pits) and the pig intestinal tract (feces) using 16S rDNA gene cloning, sequencing, and analyses; (2) Conduct conventional microbiological isolation, identification and characterization of bacterial species in swine waste handling facilities (i.e., pits) and the pig intestinal tract (feces); (3) Perform physiological examination of the production of odor associated chemicals by the predominant bacteria of swine feces and waste storage pits; and (4) Develop hybridization analyses for identification of population shifts in swine feces and waste handling facilities. I am also carrying out analyses of antibiotic resistant bacteria from the swine feces and manure storage pits by isolation of pure cultures and PCR identification of specific antibiotic resistance genes.

Senior Research Associate, The Ohio State University

PhD in Molecular Biology, New Mexico State University

Postdoctoral Fellow in Molecular Microbial Ecology, University of British Columbia, Canada

My research interests center on the microbial ecology inside (the gastrointestinal track) and outside (the surrounding environments) of farm animals. Both culturing-based and culturing-independent molecular methodologies (e.g. quantitative PCR, RISA, DGGE, SARST-V1, metagenomics cloning, etc.) are used to analyze individual microbial populations, which have important impact on farm animal production, and microbial communities in the context of enhancing feed/additive utilization, improving antibiotic applications, designing more effective probiotics cultures, and minimizing environmental contamination by farm animal production. I am currently examining the microbial (eubacterial and methanogenic) diversity in the rumen and population dynamics in response to dietary manipulations. Another on-going project is focused on the ecology of antimicrobial resistance to tetracyclines and erythromycines in relation to antibiotic usage in food-animal production. In collaboration with Dr. Jeffery Firkins, ruminal protozoan populations and communities are also being analyzed using molecular techniques, to better understand the roles that rumen protozoa play in ruminal protein metabolism.