胎牛血清促进色素上皮衍生因子在皮肤角质形成细胞和成纤维细胞中的表达

下载PDF阅读器目的:探讨表皮角质形成细胞和真皮成纤维细胞中色素上皮衍生因子(PEDF) 表达的影响因素.方法:体外培养角质形成细胞和成纤维细胞,并以10%FBS(胎牛血清)刺激,通过免疫荧光和Western blot检测PEDF的表达.结果:PEDF大多位于细胞浆中,但在细胞核中也有少量表达.细胞浆中PEDF并非均质型分布,而是呈细颗粒状集聚.10%FBS促进角质形成细胞和成纤维细胞中PEDF的集聚和表达,而且这一分布形式不受组胺和佛波肉豆蔻醋酸(PMA) 的影响.结论:10% FBS促进角质形成细胞和成纤维细胞中PEDF的集聚和表达.

Expression of VEGFR-2 on HaCaT cells is regulated by VEGF and plays an active role in mediating VEGF induced effects

Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 play important roles in mitogenesis and chemotaxis of endothelial cells. In normal human skin, VEGF is expressed and secreted by epidermal keratinocytes. Emerging data suggest that keratin

Immunolocalization and expression of vascular endothelial growth factor receptors (VEGFRs) and neuropilins (NRPs) on Keratinocytes in human epidermis

Vascular endothelial growth factor (VEGF) plays an important role in normal and pathological angiogenesis. VEGF receptors (VEGFRs, including VEGFR-1, VEGFR-2, and VEGFR-3) and neuropilins (NRPs, including NRP-1 and NRF-2) are high-affinity receptors for V

Expression of human epidermal growth factor gene in cyanobacteria

The human epidermal growth factor (hEGF) is a small single-chain polypeptide of 53 amino acid residues. It can stimulate the proliferation of many cell types, mainly those of epidermal and epithelial tissues both in vivo and in vitro. A vector pRL-hEGF was constructed using plasmids pRL-489 and pUC-hEGF. The synthetic hEGF gene was recombined into the downstream of strong promoter psbA in plasmids pRL-489. Then, the vector was introduced into Synechococcus sp. PCC 7002 and Anabaena sp. PCC 7120 by triparental conjugative transfer. The transformation was confirmed by PCR amplification. The pRL-hEGF is thought to be retained as a plasmid form in the transgenic Anabaena sp. PCC 7120, since it can be recovered. However, it has been integrated into the chromosome of Synechococcus sp. PCC 7002 as there is no duplication origin in the pRL-hEGF in this cyanobacterium. and plasmid cannot be isolated from the Synechococcus sp. PCC 7002 either. The radioimmunoassay (RIA) proved that the hEGF gene has been expressed as the protein existed in these two strains of transgenic cyanobacteria, and the hEGF protein in Anabaena sp. PCC 7002 could be secreted into the medium.

Phenoloxidase, a marker enzyme for differentiation of the neural ectoderm and the epidermal ectoderm during embryonic development of amphioxus Branchiostoma belcheri tsingtaunese

The development of phenoloxidase during amphioxus embryogenesis was spectrophotometrically and histochemically studied for the first time in the present study. It was found that (1) PO activity initially appeared in the general ectoderm including the neural ectoderm and the epidermal ectoderm at the early neurala stage but not in the mesoderm or the endoderm, and (2) PO activity disappeared in the neural plate cells but remained unchanged in the epidermal cells when the neural plate was morphologically quite distinct from the rest of the ectoderm. It is apparent that PO could serve as a marker enzyme for differentiation of the neural ectoderm from the epidermal ectoderm during embryonic development of amphioxus. (C) 2000 Elsevier Science ireland Ltd. All rights reserved.

Forced Dissociation of Selectin-ligand Complexes Using Steered Molecular Dynamics Simulation

Selectin-ligand interactions are crucial to such biological processes as inflammatory cascade or tumor metastasis. How transient formation and dissociation of selectin-ligand bonds in blood flow are coupled to molecular conformation at atomic level, however, has not been well understood. In this study, steered molecular dynamics (SMD) simulations were used to elucidate the intramolecular and intermolecular conformational evolutions involved in forced dissociation of three selectin-ligand systems: the construct consisting of P-selectin lectin (Lec) and epidermal growth factor (EGF)-like domains (P-LE) interacting with synthesized sulfoglycopeptide or SGP-3, P-LE with sialyl Lewis X (sLeX), and E-LE with sLeX. SMD simulations were based on newly built-up force field parameters including carbohydrate units and sulfated tyrosine(s) using an analogy approach. The simulations demonstrated that the complex dissociation was coupled to the molecular extension. While the intramolecular unraveling in P-LESGP-3 system mainly resulted from the destroy of the two anti-parallel sheets of EGF domain and the breakage of hydrogen-bond cluster at the Lec-EGF interface, the intermolecular dissociation was mainly determined by separation of fucose (FUC) from Ca2+ ion in all three systems. Conformational changes during forced dissociations depended on pulling velocities and forces, as well as on how the force was applied. This work provides an insight into better understanding of conformational changes and adhesive functionality of selectin-ligand interactions under external forces.

Microfluidic effects of transporting signaling components in cell coculture chips

A theoretical model has been developed to investigate the microfluidic transport of the signaling chemicals in the cell coculture chips. Using an epidermal growth factor (EGF)-like growth factor as the sample chemical, the effects of velocities and channel geometry were studied for the continuous-flow microchannel bioreactors. It is found that different perfusion velocities must be applied in the parallel channels to facilitate the communication, i.e., transport of the signaling component, between the coculture channels. Such communication occurs in a unidirectional way because the signaling chemicals can only flow from the high velocity area to the low velocity area. Moreover, the effect of the transport of the signaling component between the coculture channels on the growth of the monolayer cells and the multicellular tumor spheroid (MTS) in the continuous-flow coculture environment were simulated using 3D models. The numerical results demonstrated that the concentration gradients will induce the heterogeneous growth of the cells and the MTSs, which should be taken into account in designing the continuous-flow perfusion bioreactor for the cell coculture research.

榧属（Torrya Arn.）分类研究及其在红豆杉科中的系统位置

本论文对榧属(TorreyI)的研究历史作了回顾．以形态性状为依据，结合叶片的解剖，花粉表面的电镜观察，以及种子蛋白的电泳等，对榧属的系统分类进行了研究。结果表明： l、支持根据种子胚乳深皱与微皱分榧属为两个组的观点． 2、从叶片气孔带乳突的特征及种子蛋白电泳带的类型，似可支持榧属两组的建立． 3、根据各种榧树叶肉组织中石细胞的观察，不支持将石细胞的有无作为分组的特征。 4、云南榧与巴山榧叶的解剖特征有较多相似性，但在石细胞的含量、栅栏组织细胞层数及结晶大小等方面存在差别．考虑到其他性状及地理分布，认为将云南榧改为巴山榧的变种较为自然。 5、本属植物花粉形态较为一致，种问无明显的差别．对组和种的划分无重要参考价值． 6、经研究订正，榧属共6种2变种和11个栽培变种。其中1新变种（九龙山榧），1改级新组合（云南榧），6个新载培变种。 7、结合前人的研究，作者归纳出红豆杉科植物的进化趋势，支持榧属为进化类群的观点。

银杏类植物的叶表皮特征及其气孔频度对大气CO2浓度的指示

本文以跨越漫长地质历史时期的银杏类植物为研究对象，首次尝试在大的时间尺度上利用单一植物类群的气孔频度估测古大气CO2浓度的变化趋势。 一、借助多种研究手段对现代银杏（Ginkgo biloba）和9种化石银杏的叶表皮特征进行调查，并对现代银杏叶片蜡质晶体的形态结构和气孔发育过程进行了研究。应用荧光显微镜观察晚三叠世一种拜拉植物的角质层特征，根据其气孔下生型和平直的表皮细胞垂周壁等特点建 立新种—宁蒗拜拉（Baiera ninglangensis sp. nov.）。 二、在大气CO2浓度相对稳定的条件下，对不同条件下（不同季节，长短枝间，不同冠层间，不同叶片面积，雌雄树间）银杏叶片气孔密度和气孔指数的调查结果表明，其它环境因子对银杏气孔频度的影响很有限，而且通过一定的采样、测量和分析策略，可以排除其他环境和生物因子对气孔特征的影响。 三、74年间，大气CO2浓度上升55μmol•mol-1的同时，银杏的气孔密度降低了27%。而3属8种中生代和新生代银杏类植物在9个时间点的气孔密度和气孔指数都低于现存最近对应种的值，意味着当时的大气CO2浓度都高于目前的水平。根据最新评估标准，以气孔比率定量估算各个地质时代的大气CO2浓度，与前人的工作以及通过地球物理化学方法获得的显生宙大气CO2浓度进行比较。