Fibronectin purification from human plasma in a packed-bed column system with gelatin immobilized PHEMA microspheres

Bioaffinity chromatography has a unique and powerful role that is used as a purification tool in the production of therapeutic plasma protein derivatives. In this study, a bioaffinity-ligand, i.e. gelatin, was covalently immobilized with PHEMA microspheres (150-200 μm in diameter). The affinity sorbent carrying 7.5 mg gelatin g^-1 polymer was then used to separate fibronectin from human plasma in a packed-bed column system. Fibronectin separation from human plasma on unmodified PHEMA microspheres was 0.45 mg g^-1, while much higher adsorption values, up to 21.8 mg g^-1, were obtained with gelatin-immobilized microspheres. The fibronectin adsorption capacity of the microspheres decreased with an increase in the recirculation rate of plasma. Fibronectin adsorption increased with decreasing temperature, and the maximum adsorption achieved at 4°C (26.3 mg fibronectin g^-1). Up to 94.7% of the adsorbed fibronectin was desorbed by using 2 M urea in the presence of 1 M sodium chloride as elution agent. The adsorption-desorption cycle was repeated ten times using the same affinity column. There was no remarkable reduction in the adsorption capacity of the gelatin-immobilized PHEMA microspheres.     

丰肉结海绵相关链霉菌LS298活性代谢产物研究

目的对我国南海丰肉结海绵相关链霉菌LS298的活性代谢产物进行研究。方法采用硅胶柱、凝胶柱及HPLC等色谱方法对LS298发酵产物进行分离纯化;通过核磁共振、质谱等波谱分析手段对分离得到的化合物进行结构鉴定;以滤纸片扩散法及MTT法分别检测其抗菌和抗肿瘤活性。结果分离得到12个化合物。分别为尿嘧啶核苷、2'-脱氧尿嘧啶核苷、邻苯二甲酸正丁二酯、邻苯二甲酸二(2-乙基己)酯、3-甲酰胺-吲哚、环(脯氨酸-缬氨酸)、环(脯氨酸-苯丙氨酸)、环(脯氨酸-酪氨酸)、环(脯氨酸-亮氨酸)、meleagrin、5-hydroxyectoine和echinomycin。其中,3-甲酰胺-吲哚系首次从微生物中分离得到;meleagrin系首次从放线菌中分离得到。初步的药理研究表明,化合物echinomycin不仅具有较强的抗菌活性,亦具有很强的体外抗肿瘤活性。结论化合物echinomycin是链霉菌LS298的主要抗菌和抗肿瘤活性成分之一。     

DNA-responsive uniform latex particles based on p-chloromethylstyrene

In this study, DNA binding properties of poly(ethylenimine) (PEI)-attached uniform poly(p-chloromethystyrene) (PCMS) particles were investigated. Spherical PCMS latex particles with an average size of 1.75 μm were obtained by the dispersion polymerization of p-chloromethylstyrene (CMS). PEI was covalently attached onto the PCMS particles via a direct chemical reaction between amine and chloromethyl groups, with the equilibrium binding capacities up to 41 mg PEI/g PCMS. In aqueous media, PEI attached-uniform PCMS particles showed an irreversible aggregation behaviour in the presence of DNA. To predict unknown DNA concentration, the aggregation response of these particles to the presence of DNA was quantified by spectrophotometry. Plain PCMS and PEI attacheduniform PCMS particles were also utilized as sorbents in DNA adsorption experiments conducted at +4°C in a phosphate buffer medium at pH 7.4. DNA immobilization capacities up to 45 mg DNA/g PCMS could be achieved with the PEI attached particles.