Isolation and Purification of Cationic Proteins from Microaerophilous Stationary Phase Culture Supernatants of Babesia bigemina

Abstract

Tewari, A.K., Mishra, A.K. and Rao, J.R. 2000. Isolation and purification of cationic proteins from microaerophilous stationary phase culture supernatants of Babesia bigemina. J. Appl. Anim. Res., 18: 41–48.

Babesia bigemina was maintained in short-term culture by microaerophilous stationary phase culture system. The pooled 3 day culture supernatants were centrifuged at 12000 × g for 30 min and the supernatant collected was filtered through 0.45 μm millipore filter. A two-step protocol was used for purification of cationic babesial proteins by ammonium sulphate precipitation and CM-cellulose chromatography. Five polypeptides were identified as cationic babesial proteins in Coomassie blue stained polyacrylamide gradient gel (5–15%) under reducing conditions in the molecular weight range (Mr) of 150 to 48 kDa. The partially purified babesial merozoite antigen revealed major polypeptides in the Mr of 255 to 75 kDa with an overwhelming contamination of host corpuscular proteins of 290-28 kDa.

Key words:

• Babesia bigemina
• MASP culture
• purification
• cation-exchange
• chromatography