1. Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
2. Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
3. Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
4. Department of Biology, University of Texas at San Antonio, San Antonio, Texas, USA
5. Department of Biology, Texas Christian University, Fort Worth, Texas, USA
6. Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
7. Department of Pathology, Duke University School of Medicine, Durham, North Carolina, USA