Yahr is honored for important work on the genetics and physiology of Pseudomonas aeruginosa and Escherichia coli, research that is already suggesting new paths for treating infections caused by these microorganisms.
While still a graduate student, Yahr discovered the type III secretion system in P. aeruginosa. This system acts like a syringe to inject toxins from P. aeruginosa into the host cell. In addition, he defined the genes required for this system to function, key elements governing its expression, and several of the virulence factors it secreted. As a result of this groundbreaking research, one of the type III proteins has been identified as a possible vaccine candidate for the treatment of Pseudomonas infections in patients with cystic fibrosis, AIDS, or other disorders, for whom treatment options are often quite limited.
Yahr's other research interests have important clinical implications as well. As a postdoctoral fellow at Dartmouth Medical School, Hanover, New Hampshire, he became interested in improving the technology for studying the twin-arginine translocation (TAT) system, a poorly understood mechanism for moving folded preproteins across or into the inner membrane of E. coli. He developed a TAT translocation assay that is now being used in several laboratories in the United States and Europe. TAT translocation has recently been identified as a factor in P. aeruginosa virulence as well, so Yahr's assay is both innovative and timely.
A graduate of the University of Wisconsin-Stevens Point, where he earned a B.S. degree in biology, Yahr received his M.S. and Ph.D. degrees in microbiology from the Medical College of Wisconsin, Milwaukee.
The Merck Irving S. Sigal Memorial Awards will be presented at the 104th General Meeting of the American Society for Microbiology (ASM), May 23–27, 2004, in New Orleans, Louisiana. ASM is the largest single life science society, composed of over 42,000 scientists, teachers, physicians, and health professionals. Its mission is to promote research and training in the microbiological sciences and to assist communication between scientists, policymakers, and the public to improve health, economic well-being, and the environment.