Calendar
Calendar
Seminar Series: Fall 2006
All seminars are Fridays, 3-4pm Druckenmiller room 20 unless otherwise noted.
November 3, 2006
Cynthia M. Friend
Chair, Department of Chemistry and Chemical Biology, Harvard University
Theodore Williams Richards Professor of Chemistry
Department of Chemistry and Chemical Biology
Professor of Materials Science
Division of Engineering and Applied Science
Associate Director of Materials Research Science and Engineering Center
Seminar: Chemistry on the Edge-Surfaces
Abstract: Surfaces are ubiquitous and are key elements of many aspects of our lives and the economy. Our studies of Au surfaces will be used to illustrate how atoms are mobile on an atomic scale, even though the surfaces are solid. The role of this mobility in promoting important chemical reactions and determining the properties of these materials will be discussed.
3-4 PM Druckenmiller room 20
General Lecture: The Changing Landscape: Developing a Career in Science
Abstract: The beauty of science is the constant evolution of our understanding of nature. Advances in science are promoted by new technological developments, educational approaches, modes of doing research, and the influx of new talent. Examples of the development of new methods for scientific research will be used to illustrate how the nature of questions and our approach to answering them change. At the same time, the tremendous impact on society of some of these developments will be discussed. Finally, the role of the scientist and how to approach becoming a scientist will be discussed.
7:30 PM
November 10, 2006
Jim Morken
Professor of Chemistry, Boston College
October 27, 2006
Heidi Bialk
Postdoctoral Research Fellow
Department of Chemistry & Biochemistry
Old Dominion University
Two-dimensional NMR Studies of the Chemical Incorporation of Sulfonamide Antimicrobials into Humic Substances
Abstract: Sulfonamide antimicrobials are synthetic agents applied extensively in both human and veterinary medicine. These antimicrobials are introduced into soil and water environments via the disposal of human and animal waste, run-off and infiltration of agricultural fields, biosolids application, and effluent irrigation. The primary concern with the release of antibiotics is an increase in selective pressure that could potentially lead to the proliferation of resistant pathogens. Evaluation of the risks posed by sulfonamides requires an understanding of the mechanisms governing their fate in soil and water environments. One potentially important mechanism is covalent cross-coupling or chemical incorporation of sulfonamides into humic substances by nucleophilic addition or radical-radical coupling. Naturally occurring phenoloxidases (e.g., peroxidases, laccases) present in soil can mediate the cross-coupling of xenobiotic moieties (e.g., aromatic amines and phenols) into humic substances. We previously demonstrated the nucleophilic addition of sulfamethazine to the model humic constituent, syringic acid, when incubated with Arthromyces ramosus peroxidase (ARP) (Bialk et al. Environ. Sci. Technol. 2005, 39, 4436-4473). The primary objective of this study was to determine whether sulfonamide antimicrobials cross-couple with complex humic substances while in the presence of ARP. A secondary objective was to determine the nature of the covalent linkage formed. We employed isotopically labelled sulfonamides in these experiments, [phenyl-13C6]-sulfamethazine and 15N-sulfapyridine (15N-SPD), to allow detection of covalent linkages formed with humic material by nuclear magnetic resonance (NMR) spectroscopy. Two-dimensional 1H-13C heteronuclear single quantum correlation (HSQC) and 1H-15N heteronuclear multiple bond coherence (HMBC) NMR experiments were conducted to detect covalent bond formation occurring via the anilinic nitrogen common to all sulfonamides. 15N chemical shifts indicated that 15N-SPD reacted with humic substances to form anilinohydroquinones and anilinoquinones. Such covalent linkages may not only diminish the antibiotic potency of bound sulfonamides but also result in their immobilization. These studies therefore suggest that phenoloxidases may play an important role in the detoxification of sulfonamide antimicrobials in soil.
2:30PM REFRESHMENTS Druckenmiller Room 26
3:00PM SEMINAR Druckenmiller Room 20
September 15, 2006
Ernie Levroney '96
Bowdoin Alum, UCLA Ph.D.
September 22, 2006
Summer Research Poster Presentations
Druckenmiller Atrium (Bio, Chem and Biochem students)
Tuesday October 10, 2006
Harold McGee
Harold McGee writes about the chemistry of food and cooking. His book On Food and Cooking: The Science and Lore of the Kitchen was named best food reference book by two culinary associations. Bon Appetit magazine named him food writer of the year in 2005
Sponsored by the Chemistry & Biochemistry departments and the Annie Talbot Cole Lectureship Fund
Cleaveland 151 7:00 pm
Open to the public
October 20, 2006
Adria Elskus
Associate Professor of Biological Sciences and Cooperating Associate Professor of Marine Sciences, University of Maine.
USGS Research Fishery Biologist/Toxicologist