Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan, ROC. cllu@mail.nctu.edu.tw|Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan, ROC. cllu@mail.nctu.edu.tw|Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan, ROC. cllu@mail.nctu.edu.tw|Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan, ROC. cllu@mail.nctu.edu.tw