Department of Chemistry

Visiting Speaker

Professor  James E. Penner-Hahn

Department of Chemistry and Biophysics, University of Michigan

will present a seminar entitled:

"Inorganic Physiology: Distribution and Speciation of Metal Ions in Biological Systems"

Abstract:
Metal ions play a critical role in virtually all biological processes, including catalysis, electron transport, structural stability, and cellular signaling.  In the absence of sufficient metal, critical cellular functions fail or less efficient mechanisms are triggered, frequently leading to pathological conditions.  Many metals are both bio-essential and toxic, the details being dependent on the metal, concentration, and organism; others are exclusively toxic.  Consequently, metal ion levels within cells are tightly regulated, and a complex set of machinery has evolved to control the uptake, storage, and efflux of metals.  A critical piece of information for understanding the control of metal metabolism is direct measurement of the concentration and speciation of metal ions, both in tissue and also on the sub-cellular length scale.  Modern x-ray microprobe and nanoprobe beam lines make it possible to determine absolute metal concentrations with a spatial resolution as good as ~100 nm and ~mM detection limits.  In favorable circumstances, spatially-resolved metal speciation can be determined using x-ray absorption spectroscopy.  We have used these methods together with conventional x-ray absorption spectroscopy to investigate metal ions in a variety of biological environments.

Acknowledgements: Supported in part by NIH GM70545 and GM38047.  Synchrotron beam time at the Advanced Photon Sources is supported in part by the US Department of Energy.

Friday, June 12, 2009 at 3:00 p.m.  ST 135     Department Contact: Dr. F. Jalilehvand