Genetic Engineering Laboratory;
Academy of Military Medical Seienees;
Changehun 130062;
P. R. China;
College of Animal Seienee and Veterinary Medieine;
Liaoning Medieal University;
Jinzhou 121001;
P. R. China;
College of Animal Seienee and Veterinary Medieine;
Yunnan Agrieultural University;
Kunming 650201;
P R. China;
Key Laboratory for Moleeular Enzymology and Engineering of Ministry of Edueation;
Jilin University;
Changehun 130021;
P. R. China;