共查询到19条相似文献，搜索用时 171 毫秒
1.
选择素及其在胚胎附植中的作用 总被引：1，自引：0，他引：1
选择素是已知的细胞黏附分子(CAMs)家族之一,共有3个成员组成,其主要生理功能是在炎症发生时介导白细胞与血管内皮细胞之间的起始黏附。近年来研究资料显示,选择素还在受精、肿瘤细胞转移和胚胎附植等过程中发挥着重要的作用,其中滋养层L-选择素介导胚泡滋养层与子宫之间的相互作用,在胚胎附植时发挥桥梁作用。 相似文献
2.
结合素(bindin)属于配子识别蛋白的重要种类之一,是雄性海洋生物精巢或精子中特有的凝集素样的不溶性颗粒蛋白。在海洋生物体外受精过程中,当顶体反应发生时,精子释放出成熟的bindin蛋白可特异性地识别特定卵子表面的蛋白受体,进而促进精卵结合,在保障海洋生物体外受精准确性和维系海洋生物物种独立性、稳定性等方面具有重要意义。棘皮动物属后口动物,是无脊椎动物的高等类别,棘皮动物的受精生物学和性别选择机制一直是基础生物学研究和水产养殖研究的热点和焦点内容。本研究中就近年来棘皮动物结合素bindin基因的结构信息、生物功能以及分子进化特点进行综述,以期为进一步了解棘皮动物结合素bindin的功能、分子进化特点及其在棘皮动物配子识别和性别选择中的作用提供参考。 相似文献
3.
日粮中添加精氨酸可促进怀孕母猪胎盘生长发育,提高怀孕母猪繁殖性能。胎盘生长发育主要为滋养层细胞增殖、分化、侵润及融合等过程。因此,文章综述精氨酸及其代谢产物对滋养层细胞增殖、分化、生殖激素分泌和细胞生长因子表达调控作用及其相关信号通路影响等方面研究进展,旨在阐明精氨酸调控怀孕母猪胎盘滋养层细胞,促进怀孕母猪胎盘生长发育作用机理,以期为精氨酸在母猪繁殖营养应用提供科学依据。 相似文献
4.
通过研究6种中药生物碱对细菌内毒素（LPS）作用下猪血管内皮细胞分泌细胞因子血栓素B2（TXB2）,内皮素-1（ET-1）和E-选择素（E-selectin）的影响,拟探讨生物碱抗LPS的药理作用机制。培养猪血管内皮细胞至单层融合状态,加入LPS刺激,3 h后加入高、中、低3种浓度的6种中药生物碱青藤碱、防己诺林碱、水苏碱、川芎嗪、苦参碱和吴茱萸碱,继续培养21 h后收集细胞上清液,用ELISA测定TXB2,ET-1和E-selectin的含量。结果,水苏碱高剂量组和川芎嗪高剂量组的TXB2含量极显著低于LPS对照组,川芎嗪中剂量组和吴茱萸碱高剂量组显著低于LPS对照组;苦参碱高剂量组的ET-1含量极显著低于LPS对照组,青藤碱高剂量组显著低于LPS对照组;防己诺林碱高剂量组和吴茱萸碱中剂量组的E-selectin含量显著低于LPS对照组。结果提示六种中药生物碱具有明显的抗细菌内毒素作用,可在由TXB2,ET-1和E-selectin介导的机体凝血、休克和炎症等病理损伤过程中发挥治疗作用。 相似文献
5.
刀豆凝集素提取分离条件的优化及其凝集活性 总被引：1，自引：0，他引：1
凝集素是一类多价的、非免疫来源的、对糖及其缀合物高度专一识别的蛋白质[1]。它们广泛存在于各种生物体中,并且在病毒、细菌、支原体、寄生虫的感染,在细胞与可溶性组分之间的寻靶作用,在受精作用,在癌细胞的转移、生长、分化等过程中,都起着重要作用[2,3]。豆科植物凝集素具 相似文献
6.
目的：研究表皮生长因子受体(EGFR)在妊娠滋养细胞疾病的表达及其临床意义。方法：采用免疫组化方法，检测石蜡包埋的l05例妊娠滋养细胞疾病和20例正常早孕绒毛组织EGFR蛋白表达水平。结果：EGFR蛋白在妊娠滋养细胞疾病和正常早孕绒毛中均有不同程度的表达，在合体滋养层中，妊娠滋养细胞疾病和正常早孕绒毛组织均强烈表达EGFR蛋白，它们之间的表达差异无显著性。在细胞滋养层，正常早孕绒毛EGFR蛋白表达显著高于葡萄胎(P＜0．01)，葡萄胎EGFR蛋白表达显著高于侵蚀性葡萄胎和绒癌(P＜0．01)，EGFR蛋白表达在侵蚀性葡萄胎和绒癌之间差异无显著性(P＞0．05)。EGFR蛋白表达水平与滋养细胞肿瘤临床指标无关。结论：EGFR表达降低反映了在妊娠滋养细胞疾病发生发展过程中EGFR起重要作用。 相似文献
7.
目的:比较五味子木脂素成分对CCl4致L02肝细胞损伤的保护作用,筛选出护肝作用最大的主活性成分。方法:体外培养L02细胞,分别以不同浓度五味子甲素、乙素、丙素、醇甲、醇乙、酯甲对细胞加以保护,CCl4体外诱导细胞损伤;MTT法测定细胞存活率;通过试剂盒的方法分别检测各组细胞上清液中谷丙转氨酶(ALT)和谷草转氨酶(AST)活力。结果:CCl4最佳造模浓度为80mmoL·L-(1P0.01);5～20μmoL·L-1的五味子木脂素单体均能增加L02肝细胞存活率(P0.01);考察浓度为20μmol·L-1时,均可抑制CCl4引起ALT、AST活性的升高(P0.05或P0.01);结论:通过比较得出五味子乙素护肝作用最强。 相似文献
8.
《山东省农业管理干部学院学报》2016,(3):29-31
把氨基寡糖素水剂,也就是所谓的海岛素运用在水稻上,进行小区之间的比较,全面观察海岛素在水稻生长过程中发挥的重要作用,能够有效的促进水稻的生长、加强抵抗性,进一步增加其产量,通过试验找到使用海岛素的科学方式。 相似文献
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10.
以MTT法测定紫草素对乳腺癌细胞株MCF-7等的生长抑制作用,并通过形态学分析、Hoechst荧光染色、流式细胞术及免疫印迹等观察紫草素诱导乳腺癌细胞凋亡的形态学、生化特征改变及凋亡的可能机制.结果表明:紫草素对乳腺癌细胞株有显著抑制生长作用,效应呈时间和剂量的依赖性,24h半数抑制浓度(IC50)均在10μmol·L-1以下.紫草素诱导MCF-7等乳腺癌细胞发生典型的细胞凋亡,细胞周期阻滞于S期,凋亡过程中产生了85ku大小的PARP裂解片段,此效应可被广谱caspase抑制剂抑制,表明紫草素可能经caspase途径诱导MCF-7细胞发生凋亡. 相似文献
11.
炎症反应与白细胞迁移 总被引：2，自引：0，他引：2
人体自我防御中,白细胞定向迁移是先天性免疫必不可少的步骤。然而白细胞在创伤部位的募集也导致了炎症反应的发生。白细胞的移动和它周围微环境的变化精确地调控着一系列级联事件。趋化因子在白细胞迁移过程中起着重要的作用,对介导细胞黏附和迁移的趋化因子的深入研究将有助于对疾病病理状态的了解和控制。 相似文献
12.
How stem cells are recruited to and maintained in their niches is crucial to understanding their regulation and use in regenerative medicine. Here, we demonstrate that DE-cadherin-mediated cell adhesion is required for anchoring germline stem cells (GSCs) in their niches in the Drosophila ovary. Two major components of this adhesion process, DE-cadherin and Armadillo/beta-catenin, accumulate at high levels in the junctions between GSCs and cap cells, one of the niche components. Removal of these proteins from GSCs results in stem cell loss. Furthermore, DE-cadherin is required for recruiting GSCs to their niche. Our study demonstrates that anchorage of GSCs in their niche by DE-cadherin-mediated adhesion is important for stem cell maintenance and function. 相似文献
13.
The mechanisms that control localization of marginal zone (MZ) B cells are poorly understood. Here we show that MZ B cells express elevated levels of the integrins LFA-1 (alphaLbeta2) and alpha4beta1 and that they bind to the ligands ICAM-1 and VCAM-1. These ligands are expressed within the MZ in a lymphotoxin-dependent manner. Combined inhibition of LFA-1 and alpha4beta1 causes a rapid and selective release of B cells from the MZ. Furthermore, lipopolysaccharide-triggered MZ B cell relocalization involves down-regulation of integrin-mediated adhesion. These studies identify key requirements for MZ B cell localization and establish a role for integrins in peripheral lymphoid tissue compartmentalization. 相似文献
14.
Genbacev OD Prakobphol A Foulk RA Krtolica AR Ilic D Singer MS Yang ZQ Kiessling LL Rosen SD Fisher SJ 《Science (New York, N.Y.)》2003,299(5605):405-408
Trophoblast adhesion to the uterine wall is the requisite first step of implantation and, subsequently, placentation. At the maternal-fetal interface, we investigated the expression of selectin adhesion systems that enable leukocyte capture from the bloodstream. On the maternal side, human uterine epithelial cells up-regulated selectin oligosaccharide-based ligands during the window of receptivity. On the fetal side, human trophoblasts expressed L-selectin. This ligand-receptor system was functional, because beads coated with the selectin ligand 6-sulfo sLe(x) bound to trophoblasts, and trophoblasts bound to ligand-expressing uterine luminal epithelium in tissue sections. These results suggest that trophoblast L-selectin mediates interactions with the uterus and that this adhesion mechanism may be critical to establishing human pregnancy. 相似文献
15.
Human monocytic cell lines derived from cord leukocytes by co-cultivation with irradiated CM-S cells 总被引：1，自引：0，他引：1
The CM-S cell line was established from the bone marrow of a child with congenital hypoplastic anemia and resembles its monocyte-macrophage lineage. Lethally x-irradiated CM-S cells from various passages and clones, representing different stages in the progression of the transformed growth phenotype, were tested for their ability to affect the survival and proliferation of normal human cord or adult blood leukocytes in co-culture. One clone, CM-SM, which is tumorigenic in athymic mice, consistently immortalized umbilical cord mononuclear cells but did not immortalize adult peripheral blood leukocytes. Six autonomous monocyte-like diploid cell lines were obtained and all were found to be of cord origin. Three lines were tumorigenic in athymic mice. Attempts to immortalize human leukocytes with cell-free supernatants from CM-S cells were unsuccessful. 相似文献
16.
Endothelial expression of a mononuclear leukocyte adhesion molecule during atherogenesis 总被引：109，自引：0，他引：109
An inducible rabbit endothelial adhesion molecule that is selective for mononuclear leukocytes has been identified. This adhesion protein was expressed on the surface of activated cultured endothelium in two forms, 118 and 98 kilodaltons, the amino-terminal sequence of each being highly homologous to human VCAM-1. In dietary hypercholesterolemic and Watanabe heritable hyperlipidemic rabbit models of atherosclerosis, this adhesion molecule was found to be expressed in a localized fashion by aortic endothelium that overlies early foam cell lesions. This lesion-localized expression suggests a potential endothelium-dependent mechanism for mononuclear leukocyte recruitment during atherogenesis and may provide a molecular marker for early atherosclerosis. 相似文献
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18.
Trans-endocytosis of CD80 and CD86: a molecular basis for the cell-extrinsic function of CTLA-4 总被引：1，自引：0，他引：1
Qureshi OS Zheng Y Nakamura K Attridge K Manzotti C Schmidt EM Baker J Jeffery LE Kaur S Briggs Z Hou TZ Futter CE Anderson G Walker LS Sansom DM 《Science (New York, N.Y.)》2011,332(6029):600-603
Cytotoxic T lymphocyte antigen 4 (CTLA-4) is an essential negative regulator of T cell immune responses whose mechanism of action is the subject of debate. CTLA-4 shares two ligands (CD80 and CD86) with a stimulatory receptor, CD28. Here, we show that CTLA-4 can capture its ligands from opposing cells by a process of trans-endocytosis. After removal, these costimulatory ligands are degraded inside CTLA-4-expressing cells, resulting in impaired costimulation via CD28. Acquisition of CD86 from antigen-presenting cells is stimulated by T cell receptor engagement and observed in vitro and in vivo. These data reveal a mechanism of immune regulation in which CTLA-4 acts as an effector molecule to inhibit CD28 costimulation by the cell-extrinsic depletion of ligands, accounting for many of the known features of the CD28-CTLA-4 system. 相似文献
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目的探讨白藜芦醇对辐射导致小鼠骨髓损伤的修复作用。方法 80只小鼠随机分为正常组、模型组、实验组和对照组,每组20只。除正常组外,其余各组以辐射造成小鼠骨髓型急性损伤模型;实验组和对照组分别腹腔注射白藜芦醇100mg/kg和甲基强的松龙100mg/kg,正常组和模型组则腹腔注射等量生理盐水,连续治疗7d,检测小鼠外周血白细胞、骨髓单个核细胞以及骨髓CD34＋细胞数。结果给药后实验组的白细胞计数、骨髓单个核细胞数和CD34＋细胞百分率与给药前比较差异均有统计学意义（P〈0.05）,且均高于同一时间点的模型组（P〈0.05）。实验组各时间点的白细胞数、骨髓单个核细胞数和CD34＋细胞百分率与对照组比较差异均无统计学意义（P〉0.05）。结论白藜芦醇可增加放射损伤小鼠白细胞、骨髓单个核细胞和CD34＋细胞的数目,加快骨髓造血功能的恢复。 相似文献