Evaluation of biological activity of the glycolipids by device cultured cells

将该装置培养的细胞应用于糖结合物、多糖等材料的生物活性评价。以细菌脂多糖(LPS)中的脂类A为模型化合物，将其定位于革兰氏阴性菌的外膜上，作为其生物活性中心。研究了培养细胞产生细胞因子(肿瘤坏死因子-α)的生物活性。从胡萝卜欧文氏菌的脂多糖中分离纯化了均一类脂蛋白A。此外，还制备了用于细胞评价的高灵敏度探针，并对脂类A的信号转导进行了研究。研究了抗菌肽与类脂A在分子水平上的相互作用，以阐明其表达机制和失活方法。脂质A诱导单核细胞产生细胞因子的实验表明，两种多肽抑制肿瘤坏死因子-α产生的能力与其生物物理参数如相变、分子排列等的特征变化有关，修饰后的多肽表达更强，这显然与更多的阳性氨基酸和更多的疏水氨基酸有关，导致了中和两亲性脂质A聚集体所需的更强的两亲性。通过本研究，揭示了类脂A生物活性的分子水平机制。这将导致败血症和其他由细菌感染引起的综合征的治疗。

The device cultured cells were applied for biological activity evaluation of glycoconjugates, polysaccharides, and other materials. Lipid A from bacterial lipopolysaccharide(LPS) was used as a model compound that is a biological active center of LPS which located on the outer membrane of Gram-negative bacteria. As a biological activity, cytokine(tumor necrosis factor, TNF-α) production by cultured cells was studied. Homogeneous lipid A samples were isolated and purified from LPS of Erwinia carotovora. In addition, preparation of highly sensitive probe for cell evaluation and study for signal transduction by lipid A was performed. The molecular level interaction of lipid A with antimicrobial peptides was investigated to elucidate the expression mechanisms and deactivation methods. The lipid A induced cytokine production in mononuclear cells showed that the ability of the two peptides to inhibit a TNF-α production correlates with characteristic changes of the biophysical parameters as phase transition, molecular arrangement, etc. These are much stronger expressed for the modified peptide, which apparently is connected with the higher number of positive as well as more hydrophobic amino acids, leading to a stronger amphiphilicity necessary to neutralize the amphiphilic lipid A aggregates. By this study, molecular level mechanism of biological activity for lipid A was introduced. This will lead to the remedy of sepsis and other syndromes introduced by bacterial infection.