My time is divided between being course director for the Medical Microbiology and Immunology course, lecturing in several other courses, and committee assignments at the College of Medicine and on the University level. My long-term research interests have been in bacterial toxins and their contribution to the virulence of the organisms producing them. Specifically I have been involved in elucidating the interaction of diphtheria and pseudomonas exotoxins with sensitive mammalian cells, both in vivo and in tissue culture. The questions asked bridge the fields of Microbiology and Cell Biology. They allow definition of the mechanism of action of the toxins and are useful probes to study internalization and processing of protein ligands.