1. Department of Pathology, Division of Microbiology and Immunology, University of Utah Medical School, Salt Lake City, Utah 84112
2. Institute for Genome Sciences, University of Maryland, School of Medicine, Department of Microbiology and Immunology, Baltimore, Maryland 21201
3. Department of Biological Sciences, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065
4. Biology Department, Brookhaven National Laboratory, Upton, New York 11793
5. Department of Medicine, Health Science Center, Stony Brook University, Stony Brook, New York 11794
6. Department of Medicine, University of Medicine and Dentistry of New Jersey—New Jersey Medical School, Newark, New Jersey 07103