Studies onHolothuria polii (Echinodermata) antibacterial proteins. I. Evidence for and activity of a coelomocyte lysozyme

Summary Lysozyme activity has been detected in coelomocyte lysate of the echinodermHolothuria polii. The bacteriolytic reaction was stable when the lysate was heated in acidic buffer but heat-labile in alkaline medium. An incubation temperature of 35°C, acidic pH values (5.2 and 6.2) and an ionic strength of 0.175 were found to be the best conditions for the coelomocyte enzymatic activity. A low level of lysozyme was also evidenced in cell-free coelomic fluid where it could represent a basal defense level of bacteriolytic molecules released by the coelomocytes.Acknowledgments. This work was supported in part by a grant from MRES (C. C.). The authors thank M. Lasségues and F. Lassalles for their help and criticism.     

Effects of antisense CENP-Bon the proliferation of HeLa (Tet-off) cells

In order to study the change of the expression of centromere protein B (CENP-B) caused by anfisense tcansfection, proto-eukaryotically expressed fused protein GST-CENP-B (65 ku) was injected into mouse, and a peculiar anti-CENP-B serum MaCenpB was collected. A strain of transfected HeLa Tet-off cell HaCb, which contains antisense CENP-B expressing vector pBI-EGFP-as-CenpB, was prepared. Northern blot and Western blot were used to analyze the repression of internal CENP-B in transfected cells. According to the growth curve, the proliferation of HeLa (Tet-off) is repressed by antisense CENP-B, and the multiplication time is prolonged for 32.81 h. The analysis of flow cytometry revealed that, compared with HeLa (Tet-off), the G1 cell population of HaCb is increased (△G1 = 9%) while S fraction is decreased (△S = 11%), but the G2/M phase is nearly unchanged (△G2/M=3%). In the meanwhile, the mitotic index of HaCb declines greatly compared with that of HeLa (Tet-off). Immunofluorescence showed that the assembling of centromeres in HaCb cell is arrested. These results suggest that a normal expression of CENP-B may be necessary for cell proliferation.     

植物GRAS蛋白的结构与功能

GRAS蛋白是近年来研究较多的一大类植物体中特有的蛋白家族，目前仅在拟南芥中即分离出38种蛋白质，其中不少蛋白的结构与功能已得了清晰的认识，它们的功能函盖了从分生组织的生长到激素与光的信号转导的调控的广大范围，本文对植物GRAS蛋白的结构与功能进行综述．     

爱滋病病毒全序列回文结构的研究

统计分析了爱滋病病毒全序列中中间间隔S从0到100、侧翼序列长度L从4开始的所有回文结构,通过分析不同S、L的回文结构的频数以及AT含量,发现回文结构的AT含量普遍高于全序列的AT含量.有三种辅助蛋白(Vif、Vpu、Nef)存在于病毒颗粒内,我们找出编码这三种蛋白的DNA序列,并统计出它们的回文结构,分析它们的AT含量及回文数密度(平均每1000个碱基中包含的回文数),并与丙型肝炎病毒序列回文结构进行对比.发现编码Vpu (HIV-1特有的蛋白)蛋白序列的回文结构在AT含量,和回文数密度方面均显示其特性.由此推测高AT含量的回文结构在HIV-1中起到重要作用.     

Testosterone secretion by Mongolian gerbil interstitial cells during short-term incubation depends on androgen precursors and serum proteins but not on gonadotrophins

Summary Interstitial cells from the testes of the Mongolian gerbil have been used to investigate the effects of serum proteins on testosterone production stimulated by hCG and steroidal precursors. Short-term incubation of interstitial cells with progesterone or DHEA resulted in a rapid increase of testosterone secretion; this effect was even more pronounced in the presence of calf serum. On the other hand, addition of hCG (10 mIU) had no significant effect on testosterone release during the 30-min incubation. These results demonstrate that the magnitude of the steroidogenic response of short-term incubated interstitial cells is a complex function, mainly of precursor concentrations and binding capacities of serum proteins but not of gonadotrophins.8 October 1986     

Intracellular sterol trafficking

Summary Sterols are acquired by cells either biosynthetically by the interaction of cytoplasmic and endoplasmic reticulum elements, or by endocytosis. The subcellular distribution of sterols, however, argues that sterols are trafficked quickly from sites of acquisition to target membranes, particularly the plasma membrane. The mechanisms mediating this movement might include aqueous diffusion, vesicles of either a unique pathway or of the protein secretory pathway, or carrier proteins. These mechanisms are discussed and the limited data concerning each are presented. Finally, a theory is proposed which describes how sterols and other membrane reinforcing molecules might have driven the evolution of intracellular membranes, thus establishing the dynamic membrane system of modern eukaryotes.     

食用菜籽蛋白的提取及其功能特性的研究

研究了食用菜籽蛋白的提取方法及其功能特性，并对其应用前景进行了讨论。     

昆虫几丁质酶的进化与保守性质的比较基因组学研究

昆虫几丁质酶家族属于第18家族糖苷键水解酶,主要参与昆虫蜕皮、细胞增殖和免疫等生理过程。在7个物种基因组数据中通过BLASTP和PSI-BLAST的方法获得131条chitinase和chitinase-like的同源蛋白质,利用隐马尔科夫算法,找到了几丁质蛋白的保守模体区域。通过进化树分析,将所选的蛋白分为9组,与糖苷水解酶18催化结构域和几丁质结合结构域的特性一致。通过PAML软件计算出几丁质酶的正向选择位点,发现了豌豆蚜虫中的A.pisum xp003243674.1为一条新的几丁质酶蛋白。对深入研究昆虫几丁质酶结构与功能很有帮助。     

有机溶剂沉淀法去除子宫内膜癌血清高丰度蛋白的比较研究

建立了一种简便有效、成本低廉的去除子宫内膜癌血清高丰度蛋白的方法．运用3种不同的有机溶剂（不同体积倍数）处理子宫内膜癌血清样品,SDS．PAGE电泳检测去除高丰度蛋白．结果表明：不同的有机溶剂沉淀法都能去除血清样品中绝大部分的高、中丰度蛋白,但低丰度蛋白质保留、减弱及丢失的现象不一．用1倍体积乙腈可有效去除子宫内膜癌血清样品中的绝大部分高丰度蛋白,同时保留较多的小分子量蛋白．