高密度脂蛋白（High-density Lipoprotein， HDL）是血浆中重要的脂蛋白，其主要成分为载脂蛋白AⅠ(Apoliprotein AⅠ， ApoAⅠ为了大量制备该蛋白，首先尝试利用Pichia pastoris表达系统高效表达ApoAⅠ。通过PCR扩增获得天然含人载脂蛋白ApoAⅠ的基因片断，将其插入到P.pastoris分泌型载体pPIC9K上，BglⅡ酶切线性化后电转化P.pastoris GS115，将获得的1000多个转化子依次在含不同G418浓度的YPD平板筛选高抗性转化子，得到的22个高抗性转化子经甲醇诱导，SDS-PAGE检测得到6株高表达菌。然后对其中的高表达菌株AP16的培养及诱导条件进行了优化，结果显示：接种后培养24-28h，转入诱导阶段，培养基pH值在7-7.5，菌体密度OD600=80左右，以1%甲醇诱导96h最有利于ApoAⅠ的表达，表达水平达160mg/L。14L发酵罐结果显示表达水平与摇瓶相当，均高于其它表达系统，为大批量制备奠定了基础。

用分子克隆手段获得D2氨基酸氧化酶基因后，对其在不同表达系统如大肠杆菌系统、酿酒酵母和克鲁维乳酸酵母、博伊丁假丝酵母、巴斯德毕赤氏酵母系统及动物细胞内的表达作了介绍。

以HepG2.2. 2.15细胞株为模型，以其分泌的HBsAg、HBeAg、HBV DNA及细胞存活率为观察指标，综合评价天然多肽类抗生素恩拉霉素体外抗HBV 效果。结果表明恩拉霉素对HBsAg和HBeAg的50%抑制浓度IC50分别为27μg/mL 和34μg/mL，治疗指数（TI）分别为5.9 和4.6。Southern结果显示，50μg/mL恩拉霉素对细胞内游离HBVDNA抑制率为56.8%。

Using an acyl-acyl carrier protein (ACP) as a starter unit, type Ⅱ polyketide synthases (PKSs) generate a wide range of polyketide products by successive decarboxylative condensation with the two-carkon donor malonyl (ACP). In vitro experimetts have demonstrated that polketide biosynthesis in reconstituted PKS systems requires the fatty acid synthase (FAS) enzyme malonyl CoA: ACP acyltransferase (FabD) from streptomycets. It has also been shown that holo-ACPs from a typeII PKS can catalyze self -malonylation in the presence of malonyl CoA and negate this FabD requirement. The relative roles of FabD an ACP self -malonylatin in PKS biosynthesis in vivo are still not known. Results: We have examined the ACO specificity of the Streptomyces glaucescens FabD and shown that it reacts specifically with monomeric forms of ACP, with comparable kcat IKM values for ACPs from both type II PJS and FAS systems. Incubations of tetracenomycin ACP(TcmM) withthe Escherichia coli FAS ACP (Acp P) unexpectedly revaled that, in addition to the selfmalonylation process, TcmM can catalyze the malonylation of AcpP. The ACP is two value for the TcmM-catalyzed malonylation of S. glaucescens FAS ACP is two orders of magnitude smaller than that observed for the Fabd-CAtalyzed process. Conclusion: The abilityof APKS ACP to catalyze malonylation of a FAS ACP is a surprising finding and demonstrates for the first time that PKS ACP and FabD can catalyze the same reation. The differences in the acatalytic efficiency of these two proteins rationalizes in vitro observations that FabD-independent polyketide biosynthesis proceeds only at high concentrations of a PKS ACP.

Entry of human immunodeficiency virus type 1 (HIV-1) requires CD4 and one of a family of related seven-transmembrane-domain coreceptors. Macrophage-tropic HIV-1 isolates are generally specific for CCR5, a receptor for the CC chemokines RANTES, MIP-1a, and MIP-1b, while T-cell line-tropic viruses tend to use CXCR4 (also known as fusin, LESTR, or HUMSTR). Like HIV-1, simian immunodeficiency virus (SIV) requires CD4 on the target cell surface; however, whether it also requires a coreceptor is not known. We report here that several genetically divergent SIV isolates, including SIVmac, SIVsmSL92a, SIVsmLib-1, and SIVcpz-GAB, can use human and rhesus CCR5 for entry. CXCR4 did not facilitate entry of any of the simian viruses tested, nor did any of the other known chemokine receptors. Moreover, SIVmac251 that had been extensively passaged in a human transformed T-cell line retained its use of CCR5. Rhesus and human CCR5 differed at only eight amino acid residues, four of which were in regions of the receptor that could be exposed, two in the amino-terminal extracellular region and two in the second extracellular loop. The human coreceptor was as active as the simian for SIV entry. In addition, HIV-1 was able to use the rhesus homologs of the human coreceptors, CCR5 and CXCR4. The SIV strains tested were specific for CCR5 regardless of whether they were able to replicate in transformed T-cell lines or macrophages and whether they were phenotypically syncytium inducing or noninducing in MT-2 cells. However, SIV replication was not restricted to cells expressing CCR5. SIV strains replicated efficiently in the human transformed lymphoid cell line CEMx174, which does not express detectable amounts of transcripts of CCR5. SIV also replicated in human peripheral blood mononuclear cells that were genetically deficient in CCR5. These findings indicated that, in addition to CCR5, SIV can use one or more unknown coreceptors that are expressed on human PBMCs and CEMx174 cells.