Picroside III,an Active Ingredient of Picrorhiza scrophulariiflora,Ameliorates Experimental Colitis by Protecting Intestinal Barrier Integrity

This study aims to explore the protective effects of Picroside III, an active ingredient of Picrorhiza scrophulariiflora, on the intestinal epithelial barrier in tumor necrosis factor-α (TNF-α) induced Caco-2 cells and dextran sulfate sodium (DSS) induced colitis in mice. Results show that Picroside III significantly alleviated clinical signs of colitis including body weight loss, disease activity index increase, colon shortening, and colon tissue damage. It also increased claudin-3, ZO-1 and occludin expressions and decreased claudin-2 expression in the colon tissues of mice with colitis. In vitro, Picroside III also significantly promoted wound healing, decreased the permeability of cell monolayer, upregulated the expressions of claudin-3, ZO-1 and occludin and downregulated the expression of claudin-2 in TNF-α treated Caco-2 cells. Mechanism studies show that Picroside III significantly promoted AMP-activated protein kinase (AMPK) phosphorylation in vitro and in vivo, and blockade with AMPK could significantly attenuate the upregulation of Picroside III in ZO-1 and occludin expressions and the downregulation of claudin-2 expression in TNF-α treated Caco-2 cells. In conclusion, this study demonstrates that Picroside III attenuated DSS-induced colitis by promoting colonic mucosal wound healing and epithelial barrier function recovery via the activation of AMPK.     

红细胞4．1蛋白与血型糖蛋白C／D结合位点研究进展

红细胞膜骨架与脂双层间存在着相互作用,其中带4.1蛋白与血型糖蛋白C/D间的相互作用对维持正常红细胞的形态和机械稳定性起着重要作用,研究表明,带4.1蛋白在血型糖蛋白C、D上的结合位点分别位于血型糖蛋白C的第82～98位氨基酸残基和血型糖蛋白D的第61～77位氨基酸残基．     

盐或低温胁迫对花生幼苗下胚轴ATP酶和质膜中PIP2含量的影响

经６％－１２％Ｄｅｘｔｒａｎ Ｔ７０密度梯度离心,获得了纯度较高的７ｄ龄花生幼苗下胚轴质膜和液泡膜制剂。１５０ｍｍｏｌ／Ｌ ＮａＣｌ或１０℃低温处理花生幼苗２４ｈ,其下胚轴质膜上的Ｍｇ＾２＋激活的ＡＴＰａｓｅ活性分别提高了３７．６％和１７．２％;Ｃａ＾２＋－ＡＴＰａｓｅ活性分别提高４５．８％和３３．６％。上述盐或低温处理也提高了液泡膜上Ｍｇ＾２＋激活的ＡＴＰａｓｅ活性,分别为对照的１４１．２％和１     

Processing of Procarboxypeptidase E into Carboxypeptidase E Occurs in Secretory Vesicles

Abstract: Carboxypeptidase E (CPE) functions in the posttranslational processing of bioactive peptides. Like other peptide processing enzymes, CPE is initially produced as a precursor ("proCPE") that undergoes posttranslational processing at a site containing five adjacent Arg residues near the N-terminus and at other sites near the C-terminus of proCPE. The time course of the N-terminal processing step suggests that this conversion occurs in either the Golgi apparatus or the secretory vesicles. To delineate further the site of proCPE processing, pulse/chase analysis was performed under conditions that block transit out of the Golgi apparatus (brefeldin A, carbonyl cyanide m -chlorophenylhydrazone, or 20°C) or that block acidification of vesicles (chloroquine, monensin, or ammonium chloride). The results of these analysis suggest that efficient proCPE processing requires an acidic post-Golgi compartment. To test whether known processing enzymes can perform this cleavage, purified proCPE was incubated with furin, prohormone convertase 1, or a dynorphin converting enzyme, and the products were analyzed on denaturing polyacrylamide gels. Furin cleaves proCPE within the N-terminal region, although the reaction is not very efficient, requiring relatively large amounts of furin or long incubation times. The other two peptide processing enzymes did not cleave proCPE, whereas a relatively small amount of secretory granule extract was able to convert proCPE into CPE. Taken together, these findings suggest that the conversion of proCPE into CPE occurs primarily in secretory vesicles.     

On line estimation of oxygen uptake rate for insect cells growing in a modified spinner flask

The simple design of traditional spinner flasks makes the on-line estimation of cellular metabolism impossible. An on-line estimation system has been developed and used for the monitoring of oxygen uptake rate (OUR) for insect cells growing in a modified spinner flask. Neglect of oxygen desorption from culture media is a common source of error in OUR measurements for Sf21 cells. Therefore, an algorithm was developed to compensate for the affect of such desorption process on the determination of OUR. A modified spinner flask was successfully used as a low-volume bioreactor for insect cell cultivation and the OUR measurement developed here is both convenient and reliable.     

Ca~（2＋）对叶绿素a／b钙结合蛋白波谱学特性的影响（Ⅱ）

用钙螯合亲和层析分离纯化得到的叶绿素ａ／ｂ钙结合蛋白,其荧光发射峰在６８０±１ｎｍ,钙结合后导致荧光发射峰强度降低。当再加入ＥＧＴＡ,螯合钙后,其荧光发射峰强度得以部分恢复。该蛋白在结合钙后,其圆二色谱也发生变化。这些结果表明该蛋白质的构象在结合钙后发生了变化。该蛋白质的荧光激发光谱在４４０ｎｍ和４７０ｎｍ处的激发峰表明此蛋白结合有叶绿素ａ和叶绿索ｂ。本文对叶绿素ａ／ｂ钙结合蛋白在光系统Ⅱ中的可能功能进行了讨论。     

小麦中期染色体银染蛋白的分析

对小麦中期染色体中银染蛋白的大小、形状和分布频率进行图像分析,看到：染色体顺的银染蛋白以颗粒状的形式存在,其大小不同,分布不均匀,数量差异也较大;从形状来看,大的银粒为点状,小的银粒有的为点状,有的实际为短纤维状,结果表明：染色体骨架在小麦中是真实存在的,骨架蛋白以颗粒和纤维状的形式分布于整个染色体中。     

畜禽遗传资源冷冻保存中的取样方法探讨

本文基于遗传学和数理统计原理,提出了运用冷冻生殖细胞的方法长期保存畜禽遗传资源时,冷冻生殖细胞的4种取样方法,并推证了其误差公式和最低保存数量的估计公式。最后通过实例对公式的实际应用作了说明和讨论分析。