1. Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
2. Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
3. Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
4. Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada