Vitamin C Inhibits Benzo[a]pyrene-Induced Cell Cycle Changes Partly via Cyclin D1/E2F Pathway in Human Embryo Lung Fibroblasts

INTRODUCTION Polycyclic aromatic hydrocarbons (PAHs) such as B[a]P are widespread environmental contaminants formed as byproducts of combustion[1]. PAHs have been found to be potent mammary carcinogens in rodents[2-3]. It is believed that B[a]P requires biological activation through oxidative metabolism to be carcinogenic. The ultimate carcinogenic metabolite has been considered to be the cytochrome P450 isozyme- and microsomal epoxide hydrolase- derived metabolite, BPDE, which forms…     

bFGF、EGF和NGF对人角膜内皮细胞生长调控的实验研究

目的：探讨碱性成纤维细胞生长因子（Basicfibroblastgrowthfacfor，bFGF）、表皮细胞生长因子（Epidermalgrowthfactor，EGF）和神经细胞生长因子（Nervegrowthfactor，NGF）对体外培养的人角膜内皮细胞的生长调控作用。方法：将相同数量的人角膜内皮细胞接种于96孔板。加入浓度分别为0ng／ml、1ng／ml、3ng／ml、10ng／ml、30ng／ml、100ng／ml的EGF、bFGF和NGF进行培养。5天后MTT法用检测增殖情况。结果：在0ng／ml、1ng／ml、3ng／ml、10ng／ml、30ng／ml、100ng／ml浓度下bFGF组的平均OD值分别为：0．224±0．045、0．239±0．040、0．262±0．0342、0．278±0．0319、0．281±0．0324、0．260±0．0310。EGF组的平均OD值分别为：0．228±0．0304、0．245±0．0418、0．267±0．0454、0．275±0．0347、0．271±0．0449、0．250±0．0253。NGF组的平均OD值分别为：0．216±0．0187、0．228±0．0226、0．231±O．0225、0．242±0．0279、0．245±0．0294、0．247±0．0349。结论：bFGF在30ng／ml范围内对内皮细胞生长有促进作用，并具有剂量依赖性。高于100ng／ml时促生长作用降低。EGF在10ng／ml范围内对内皮细胞生长有促进作用，并具有剂量依赖性。高于30ng／ml时促生长作用降低。NGF本次实验剂量范用内对角膜内皮细胞生长无明显作用。     

Expression and characterization of Gag protein of HIV-1 （CN） in Pichia pastoris

To express the core protein of HIV-1 of Chinese prevalent strata （HIV-1[CN]） in Pichia pastoris, the fulllength gag gene was inserted into the secretory expression vector pHILS1. Linearized recombinant plasmid pHILGAG by Sal I was electrotransformed into the yeast strain GS115, and the yeast transformants were identified by PCR. To induce the interest protein to be expressed, the PCR positive transformants were inoculated in the medium of BMGY and BMMY, mRNA of the strain was detected by RT-PCR, and the expressed protein was analyzed by SDS-PAGE, Western blotting and thin layer scanning. mRNA （1.3 kb） was amplified by RT-PCR. SDS-PAGE and Western blotting analysis showed that the molecular mass of the expressed protein was 55 kDa, which was similar to the expected value, and the expressed protein could react with McAb to HIV-1 p24. Thin layer scanning analysis demonstrated that the whole amount of the expressed protein was approximately 13% of the soluble protein in the supernatant. The recombinant yeast had good genetic stability. The optimal expression conditions of the engineering yeast were as follows： BMMY medium, 80%-90% of dissolved oxygen, 1% methanol, and 3-day-cultivation course. Gag proteins were expressed under the optimal expression condition and purified via gel filtration chromatography. The purity of the interest protein was up to 85%. After the purified proteins were inoculated into BALB/c mice, the anti-HIV-1 antibodies in the immunized mice could be detected by Western blotting.