1. Department of Biology, New York University, New York, New York.
2. Present address: Department of Neuroscience, Lerner Research Institute of the Cleveland Clinic Foundation, Cleveland, Ohio.
3. Center for Neural Science, New York University, New York, New York.
4. NYU Cancer Center, New York University, New York, New York.
5. Department of Microbiology, New York University, New York, New York.
6. Department of Microbiology, Mount Sinai School of Medicine, New York, New York.