About the Authors
Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: DAG RvdH KCM. Performed the experiments: RvdH KCM MRC. Analyzed the data: DAG RvdH KCM MRC. Wrote the paper: DAG RvdH.