College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P.R.China.|School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.|School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.|College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P.R.China.|Department of microbiology and immunology research, University of Michigan Medical School, Ann Arbor, Michigan, USA.|School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.