1. Department of Microbiology; B103 Chemical and Life Sciences Laboratory; University of Illinois; 601 S. Goodwin Ave Urbana IL 61801 USA
2. College of Life Science; South China Agricultural University; Guangzhou 510642 China
3. Department of Biochemistry; B103 Chemical and Life Sciences Laboratory; University of Illinois; 601 S. Goodwin Ave Urbana IL 61801 USA