title: [Studies on isolation, purification and antibacterial activities of beta-defensin in Yak neutrophils].
abstract: OBJECTIVE
  To isolate and purify beta-defensin from the neutrophils of Yak.
  
  
  METHODS
  The method of percoll gradient centrifugation was employed to purify neutrophils from Yak peripheral blood. The crude extraction from Yak neutrophils was isolated respectively through a way of extraction by 50 mL/L acetic acid, acid soluble extract of Yak neutrophils was obtained. Then it was further purified by Bio-Gel P-10 Polyacrylamide gel filtration and RP-HPLC, and 9 out of 22 apices showed antibacterial activity. 9 apices showing antibacterial activity were selected to be analyzed by mass spectrograph.The antibacterial activities of the extracts from every step were analyzed by agarose radial diffusion assay.
  
  
  RESULTS
  The molecular weight of the purified Yak BNBD-1-3 was determined to be 4.2, 4.6 and 4.8 kDa by mass spectrograph. BNBD-1-3 from Yak neutrophils were able to effectively kill Escherichia coli, Staphylococcus aureus and Bacillus subtilis.
  
  
  CONCLUSIONS
  Yak neutrophils have beta-defensin which have broad-spectrum antimicrobial activity, Yak defensin has an important part in innate immunity.
authors.affiliation: College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China. dkz@xbmu.edu.cn
authors.forename: Kai-zhong
authors.initials: KZ
authors.lastname: Dong
authors.forename: Si-jiu
authors.initials: SJ
authors.lastname: Yu
authors.forename: Ju-tian
authors.initials: JT
authors.lastname: Yang
authors.forename: Dong-mei
authors.initials: DM
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Cai
authors.forename: Xiao-fang
authors.initials: XF
authors.lastname: Luo
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D002417:Cattle / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects; D013058:Mass Spectrometry; D008970:Molecular Weight; D009504:Neutrophils / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects; D023083:beta-Defensins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D023083:beta-Defensins