1. The Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of Education School of Pharmaceutical Sciences Jiangnan University Lihu Avenue 1800 Wuxi 214122 P.R. China
2. School of Biology and Chemistry, Key Laboratory of Chemical Synthesis and Environmental Pollution Control-Remediation Technology of Guizhou Province Xingyi Normal University for Nationalities Xingyi 562400 China