1. Department of Chemistry, University of Akron, Akron, OH 44325‐3601, USA, Fax: +1‐330‐972‐6085
2. Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas 77555, USA
3. Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
4. Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
5. Department of Pediatrics and Molecular Microbiology andMicrobial Pathogenesis, Washington University School of Medicine, St. Louis, MO 63110, USA