Objective: To clone,identify and express the Shigalike toxin 2B(Stx2B) subunit gene of EHEC O157∶H7.Methods: A pair of primers were designed based on the Stx2B subunit gene sequence of EHEC O157∶H7.The Stx2B gene was amplified from the EHEC O157∶H7 chromosome by PCR and cloned into the pMD18-T vector.Thereafter,the gene was cut from the pMD18-T vector and cloned into the prokaryotic expression plasmid pET-28a vector.Then the recombinant plasmids were transformed into E. coli BL21(DE3) and the transformed host strain induced by IPTG.The expression protein was detected by SDS-PAGE and Western-blot analyses.Results: The Stx2B gene was successfully cloned into pMD18-T and pET-28a vectors,and the expressed protein identified by SDS-PAGE and Western blot.The molecular mass(Mr) of the expressed product was about 7 500,and the expression rate about 40%. Conclusion: The Stx2B gene was successfully cloned and effectively expressed in the prokaryotic expression system.

Objective To observe the effects of Chlamys farreri skirt glycosaminoglycan(SS-GAG) on the expressions of c-myc and TNF-? genes so as to explore the anti-atherosclerosis(AS) mechanism of SS-GAG.Methods The cell proliferation model of vascular smooth muscle cells(VSMC) was established by basic fibroblast growth factor(bFGF) induction.In Situ hybridization marked by non-isotope was applied to determine the effects of SS-GAG on the mRNA levels of c-myc and TNF in proliferative VSMC.Results The mRNA levels of c-myc and TNF in low dose group and high group of SS-GAG were obviously lower than that of model group(P

Based on their inherent relationship,some independent and verifying experiments of medical immunology were intergrated into a series of comprehensive and open experiments,which was embodied in the preparations of antiserum.so as to set up a new experiment teaching system emphasizing the training of student comprehensive capability.Achievements in training students'scientific research capacity,innovative motivation and practical working ability have been obtained and the results could provide valuable experience for innovation and reform of medical immunology experiment teaching model and method.