自组装短肽对角膜碱烧伤的作用

目的研究自组装短肽材料1%RADAl6-I水溶液对大鼠和兔角膜碱烧伤的作用.方法用1 mol/L NaOH溶液造SD大鼠和兔角膜碱烧伤模型,左眼每口滴加短肽水凝胶10μ1(2次/d),右眼为空白对照.在烧伤后的不同时间段(7、10、14d)处死大鼠,第7 d处死兔,取角膜行HE染色,光学显微镜观察结果.结果短肽水凝胶治疗组角膜上皮重生较快,皮下纤维排列较好,空白对照组皮下仍有较大空洞,皮下纤维排列紊乱,说明短肽材料能促进角膜恢复.     

桃PGIP基因及其启动子的克隆与分析

桃流胶病是一种严重危害桃树的真菌性病害,为研究PGIP基因在桃抗流胶病及抗其它真菌性病害中的作用,本研究以桃抗流胶病品种‘南京白沙'叶片为材料,对其PGIP基因及启动子序列进行克隆与分析.克隆测序获得了‘南京白沙'桃PGIP基因cDNA序列(GenBank登录号:HQ453972)和PGIP基因组DNA序列以及起始密码子上游453 bp的启动子序列(GenBank登录号:HQ453974),并将该PGIP基因命名为PpPGIP2.‘南京白沙'桃PpPGIP2序列分析显示,该DNA序列具有完整的阅读框,无内含子,与GenBank中登录的李属PGIP基因序列同源性在93%～98%之间,与测序完成的桃全基因组中该基因的序列同源性为96%;PpPGIP2编码的氨基酸序列分析显示,该氨基酸序列含有2个典型的亮氨酸重复序列,信号肽为第1～第24个氨基酸残基;PGIP基因的序列聚类图显示,除了科、属、种间的同源性差异外,桃的种内PGIP基因同源性也有较大差异;PpPGIP2启动子序列分析发现3个抗病相关元件,分别为:GT1CONSENSUS、SEBFCONSSTPR10A和WBOXATNPR1,另外还有与激素调控、胁迫有关的调控元件.本研究对‘南京白沙'桃PGIP基因和启动子的克隆与分析,将为进一步研究桃PGIP基因的表达调控及其功能分析提供参考.     

组胺H1受体功能及调节机制研究进展

组胺1型受体(H1R]受体作为组胺最主要的受体亚型,广泛分布于中枢和外周神经末梢,随着各类新型H1受体桔抗剂的发现和基因敲除动物的应用,H1R的功能研究及其活化调节机制研究也不断深入.组胺通过H1R参与调节机体多种重要的生理病理功能,如参与炎症反应、疼痛反应、血管调节、认知功能、睡眠清醒节律、饮食节律和肥胖等.H1R活化可激活磷脂酶C(PLC),PLC水解1,4,5-磷脂酰二磷酸盐产生甘油二酯(DAG)和肌醇三磷酸(IP3),后者激活细胞内Ca2+通道,活化氮氧化物合成酶,最终生成NO和鸟苷酸环化酶(cGMP),并引起钾通道开放,导致超极化;也可激活磷脂酶A2(PLA2)形成花生四烯酸(AA).H1R可通过活化其基因转录水平进行上调.本文就近十年来国外相关进展情况做一综述.     

双重荧光染色监测听毛细胞游离钙

豚鼠耳蜗分离外毛细胞经fluo-3和fura-red染色后,用激光扫描共聚焦显微镜监测其胞内游离钙的空间分布和动态变化,以fluo-3/fura-red荧光比值大小指示游离钙浓度的高低。外毛细胞胞内游离钙呈不均匀分布,荧光比值分别为细胞质1.71±0.85,质膜1.61±0.75,表皮板1.47±0.65及胞核1.39±0.66,显示细胞质游离钙浓度最高而胞核游离钙浓度最低。静息状态下连续扫描时荧光比值变化小于0.1,而在受到机械刺激后荧光比值增加幅度达0.3—1.2。实验结果表明,fluo-3和fura-red双发射比例法能更准确反映听毛细胞胞内钙的空间分布和动态变化,第二信使钙可能参与了听毛细胞的机械-电换能过程,研究了换能过程中听毛细胞钙信号的时空模式。     

A dynamic, architectural plant model simulating resource-dependent growth

BACKGROUND AND AIMS: Physiological and architectural plant models have originally been developed for different purposes and therefore have little in common, thus making combined applications difficult. There is, however, an increasing demand for crop models that simulate the genetic and resource-dependent variability of plant geometry and architecture, because man is increasingly able to transform plant production systems through combined genetic and environmental engineering. MODEL: GREENLAB is presented, a mathematical plant model that simulates interactions between plant structure and function. Dual-scale automaton is used to simulate plant organogenesis from germination to maturity on the basis of organogenetic growth cycles that have constant thermal time. Plant fresh biomass production is computed from transpiration, assuming transpiration efficiency to be constant and atmospheric demand to be the driving force, under non-limiting water supply. The fresh biomass is then distributed among expanding organs according to their relative demand. Demand for organ growth is estimated from allometric relationships (e.g. leaf surface to weight ratios) and kinetics of potential growth rate for each organ type. These are obtained through parameter optimization against empirical, morphological data sets by running the model in inverted mode. Potential growth rates are then used as estimates of relative sink strength in the model. These and other 'hidden' plant parameters are calibrated using the non-linear, least-square method. KEY RESULTS AND CONCLUSIONS: The model reproduced accurately the dynamics of plant growth, architecture and geometry of various annual and woody plants, enabling 3D visualization. It was also able to simulate the variability of leaf size on the plant and compensatory growth following pruning, as a result of internal competition for resources. The potential of the model's underlying concepts to predict the plant's phenotypic plasticity is discussed.     

Allometric growth and carbon storage in the mangrove Sonneratia apetala

Allometric growth reflects different allocation patterns and relationships of different components or traits of a plant and is closely related to ecosystem carbon storage. As an introduced species, the growth and carbon storage of Sonneratia apetala are still unclear. To derive allometric relationships of the mangrove S. apetala and to estimate carbon storage in mangrove ecosystems, we harvested 12 individual Sonneratia apetala trees from four different diameter classes in the Futian National Nature Reserve, Guangdong, China. Allometric growth models were fitted. The results showed that diameter at breast height (DBH) and wood density were better variables for predicting plant biomass (including above- and below-ground biomass) than plant height. There were significant power function relationships between biomass and DBH, with a mean allometric exponent of 2.22, and stem biomass accounted for 97% of the variation in S. apetala total biomass. Nearly isometric scaling relationships were developed between stem biomass and other biomass components. To better understand the carbon stocks of the S. apetala ecosystem, we categorized all trees into five age classes and quantified vegetation carbon storage. The S. apetala vegetation carbon storage ranged from 96.48 to 215.35 Mg C ha^?1, and the carbon storage significantly increased with stand age. The allometric equations developed in this study are useful to estimate biomass and carbon storage of S. apetala ecosystems.

     

玉米及马齿苋叶片SOD活性诱导研究

以玉米幼苗及马齿苋作材料,通过甘露醇、H2O2、臭氧和强光等胁迫后,用NBT光化还原抑制法测定叶中SOD活性的变化。臭氧和强光能诱导玉米叶片SOD活性增加。0.5mol／L甘露醇处理玉米叶片12h,SOD活性上升,至48h后下降;在该甘露醇溶液中另外加入10^-2mol/L H2O2;处理12h后SOD活性基本不变。对玉米叶片单独用10^-2mol/L H2O2诱导,30min内SOD活性上升到最高值,随着处理时间的延长又逐渐下降。用耐强光、耐干旱的野生马齿苋作为材料,与玉米相比,其叶片SOD基础活性低于后者;若予以正午强光结合渗透胁迫2h,其叶中SOD活性增幅超过玉米,从种间比较的角度旁证了SOD在抗逆性中的作用。推测植物中存在比活性氧更为直接的物理诱导机制。     

Human endothelial cell growth and phenotypic expression on three dimensional poly(lactide-co-glycolide) sintered microsphere scaffolds for bone tissue engineering

Bone tissue engineering offers promising alternatives to repair and restore tissues. Our laboratory has employed poly(lactide-co-glycolide) PLAGA microspheres to develop a three dimensional (3-D) porous bioresorbable scaffold with a biomimetic pore structure. Osseous healing and integration with the surrounding tissue depends in part on new blood vessel formation within the porous structure. Since endothelial cells play a key role in angiogenesis (formation of new blood vessels from pre-existing vasculature), the purpose of this study was to better understand human endothelial cell attachment, viability, growth, and phenotypic expression on sintered PLAGA microsphere scaffold. Scanning electron microscopy (SEM) examination showed cells attaching to the surface of microspheres and bridging the pores between the microspheres. Cell proliferation studies indicated that cell number increased during early stages and reached a plateau between days 10 and 14. Immunofluorescent staining for actin showed that cells were proliferating three dimensionally through the scaffolds while staining for PECAM-1 (platelet endothelial cell adhesion molecule) displayed typical localization at cell-cell contacts. Gene expression analysis showed that endothelial cells grown on PLAGA scaffolds maintained their normal characteristic phenotype. The cell proliferation and phenotypic expression were independent of scaffold pore architecture. These results demonstrate that PLAGA sintered microsphere scaffolds can support the growth and biological functions of human endothelial cells. The insights from this study should aid future studies aimed at enhancing angiogenesis in three dimensional tissue engineered scaffolds.     

Screening of the antigen epitopes of basic fibroblast growth factor by phage display

In order to investigate the epitope of basic fibroblast growth factor (bFGF) and its immunogenicity, the epitopes of bFGF were screened from the phage display library with monoclonal antibody GF22, which can neutralize the bio-activity of bFGF. By three rounds of screening, the positive phage clones with bFGF epitopes were selected, which can effectively block the bFGF to bind with GF22. Sequence analysis showed that the epitopes shared a highly conservative sequence (Leu-Pro-Pro/Leu-Gly-His-Phe/Ile-Lys). The sequence of PPGHFK was located at 22-27 of the bFGF. The specific immuno-response of mouse could be highly induced by phage clones with the epitopes. And the anti-bFGF activity induced by LPGHFK was 3 times higher than the original sequence, which showed that the mimetic peptide LPLGHIK might be used as a tumor vaccine in the prevention and treatment of tumor.     

鸡减蛋综合征病毒(EDSV)基因组右末端结构的分析

从中国发病鸡中分离的鸡减蛋综合征病毒（ＥｇｇＤｒｏｐＳｙｎｄｒｏｍＶｉｒｕｓ,ＥＤＳＶ）弱毒株（ＡＡ－２）,其基因组全长约为３３ｋｂ。用限制性内切酶ＨｉｎｄⅢ水解ＥＤＳＶ全基因组,构建了以ｐＢｌｕｅｓｃｒｉｐｔⅡ（ＫＳ＋）为载体的右末端片段的克隆（约４．２ｋｂ）,对其进行了序列测定和结构分析。该片段全长４１８３个碱基对（ｂｐ）,位于基因组右末端８７．３ｍ．ｕ．－１００ｍ．ｕ．。结果显示,该片段与哺乳动物腺病毒右末端Ｅ４区结构不同,与禽Ⅰ型腺病毒代表株ＣＥＬＯ右末端片段亦无同源性。本文为深入了解ＥＤＳＶ基因组结构特点,ＥＤＳＶ与其他腺病毒基因结构与功能的进化关系和ＥＤＳＶ载体的构建奠定了分子生物学基础