1. Key Laboratory of Resources Biology and Biotechnology in Western China; Ministry of Education; Faculty of Life Sciences; Northwest University; Xi'an; Shaanxi; 710069; China
2. Department of Oral Biology; Department of Medical Microbiology; University of Manitoba; 780 Bannatyne Ave.; Winnipeg; MB; R3E 0W2; Canada
3. Department of Medicine; Farncombe Family Digestive Health Research Institute; McMaster University; Hamilton; ON; L8S 4K1; Canada