1. University of California Center for Laboratory Safety, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
2. Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
3. Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Drive, Los Angeles, California 90095, United States