中成药中甘草成份的免疫学检测方法的研究

通过 ELISA和免疫印迹法分析确定了甘草蛋白 ( GRP)的特异性 ,并建立 GRP的竞争型含量分析 ELISA法 .该 ELISA法显示了良好的特异性、再现性 ( c.v.=3.9% )和检测限 ( 4 μg· L- 1 ) ,证明 GRP为甘草的特异性成分 .用该法测定 GRP同 HPLC法测定甘草甜素在三种中成药中的含量相比呈现良好的相关性 .该法简便精确快速并可同时进行大样本分析 ,为中成药中甘草成份的分析提供一种新方法 .     

The Shigella flexneri effector OspI deamidates UBC13 to dampen the inflammatory response

Many bacterial pathogens can enter various host cells and then survive intracellularly, transiently evade humoral immunity, and further disseminate to other cells and tissues. When bacteria enter host cells and replicate intracellularly, the host cells sense the invading bacteria as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) by way of various pattern recognition receptors. As a result, the host cells induce alarm signals that activate the innate immune system. Therefore, bacteria must modulate host inflammatory signalling and dampen these alarm signals. How pathogens do this after invading epithelial cells remains unclear, however. Here we show that OspI, a Shigella flexneri effector encoded by ORF169b on the large plasmid and delivered by the type ΙΙΙ secretion system, dampens acute inflammatory responses during bacterial invasion by suppressing the tumour-necrosis factor (TNF)-receptor-associated factor 6 (TRAF6)-mediated signalling pathway. OspI is a glutamine deamidase that selectively deamidates the glutamine residue at position 100 in UBC13 to a glutamic acid residue. Consequently, the E2 ubiquitin-conjugating activity required for TRAF6 activation is inhibited, allowing S. flexneri OspI to modulate the diacylglycerol-CBM (CARD-BCL10-MALT1) complex-TRAF6-nuclear-factor-κB signalling pathway. We determined the 2.0 ? crystal structure of OspI, which contains a putative cysteine-histidine-aspartic acid catalytic triad. A mutational analysis showed this catalytic triad to be essential for the deamidation of UBC13. Our results suggest that S. flexneri inhibits acute inflammatory responses in the initial stage of infection by targeting the UBC13-TRAF6 complex.     

高产DHA海洋真菌Thraustochytrium sp.N4-103脂肪酸组成及其18S rRNA基因的克隆与序列分析

采用松花粉垂钓法分离到一株docosahexaenoic acid(DHA)高产菌Thraustochytrium sp．N4-103．该菌株细胞油脂的脂肪酸组型为47．3％DHA，11．6％C22：5(n-6)，9．4％C20：5(n-3)，9．1％C20：4(n-6)和22．6％C16：0；单细胞油脂由42．6％极性脂肪，45．3％中性脂肪和12．1％糖脂组成．细胞生长与DHA合成的最佳务件：碳源为葡萄糖，氮源为酵母膏，温度为25℃。利用PCR技术分离得到N4-103菌株18S rRNA基因并进行了克隆测序，序列含有Thraustochytrids的特征插入片段．依据18S rRNA基因序列所构建的遗传进化树表明该菌是一株与Thraustochytrium sp．KK17-3具有紧密亲源关系的未报道的破囊壶菌。