1. The Medical College of Dalian University, Dalian Economic & Technical Development Zone, Dalian 116622, China
2. Department of Biochemistry and Molecular Biology, Dalian Medical University, 9 Western Section, Lvshun South Street, Lvshunkou District, Dalian 116044, China
3. Departments of Medicine and Medical Microbiology, Creighton University, 601 N 30th Street, Omaha, NE 68131, USA