Neuroendocrine regulation of structure and function in the endostyle of amphioxus, Branchiostoma belcheri

Using histological and histochemical methods the structure of the endostyle in amphioxus at different gonadal developmental stages is studied, and the immunocytochemical localization of thyroglobulin (Tg) and thyrotropin (TSH) in the endostyle, Hatschek's pit and brain vesicle is investigated. The results not only confirm the previous report that the endostyle is composed of 6 zones and the cells of zone 5 are thyroid hormone synthesizing cells, but also find the thyroxine synthesis in and secretion from zone 3. In addition, the epithelial cells in Hatschek's pit and the neural cells in brain vesicle are immunopositive for TSH, and the immunoactivity is correlated with gonadal cycle. The present study may provide morphological proof for the hypothesis that the secretory activity of thyroid cells is regulated by TSH from Hatschek's pit and brain vesicle.     

Importance of NPA motifs in the expression and function of water channel aquaporin-1

The asparagine-proline-alanine sequences (NPA motifs) are highly conserved in aquaporin water channel family. Crystallographic studies of AQP1 structure demonstrated that the two NPA motifs are in the narrow central constriction of the channel, serving to bind water molecules for selective and effi-cient water passage. To investigate the importance of the two NPA motifs in the structure, function and biogenesis of aquaporin water channels, we generated AQP1 mutations with NPA1 deletion, NPA2 de-letion and NPA1,2 double deletion. The coding sequences of the three mutated cDNAs were subcloned into the mammalian expression vector pcDNA3.1 to form expression plasmids. We established stably transfected CHO cell lines expressing these AQP1 mutants. Immunofluorescence indicated that all the three mutated AQP1 proteins are expressed normally on the plasma membrane of stably transfected CHO cells, suggesting that deletion of NPA motifs does not influence the expression and intracellular processing of AQP1. Functional analysis demonstrated that NPA1 or NPA2 deletion reduced AQP1 water permeability by 49.6% and 46.7%, respectively, while NPA1,2 double deletion had little effect on AQP1 water permeability. These results provide evidence that NPA motifs are important for water per-meation but not essential for the expression, intracellular processing and the basic structure of AQP1 water channel.     

Isolation of tomato proteinase inhibitor Ⅱ gene and the function of its intron

The genomic DNA sequence of tomato proteinase inhibitor Ⅱ gene (named tin2i, whose accession number in GenBank is AF007240) was isolated by PCR techniques. The intron sequence (TPI), with a length of 109 bp, owns typical structures of GT/AG dinucleotides at both ends and high content of AT base pairs which accounts for 80.7% of the total nucleotides. As shown by recombination experiment, the TPI sequence could efficiently promote the expression of the reporter gene gusA and this effect was independent of the position and orientation of the intron, thus showing its role as an enhancer. Such experiments as gel retardation assays, GUS histochemical staining and GUS fluorometric assays further demonstrated that TPI sequence maybe has promoter-like activity.     

Roles of a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism in ABA signal production in Arabidopsis

ABA, acting as a stress signal, plays crucial roles in plant resistance to water stress. Because ABA signal production is based on ABA biosynthesis, the regulation of NCED, a key enzyme in the ABA biosynthesis pathway, is normally thought of as the sole factor controlling ABA signal production. Here we demonstrate that ABA catabolism in combination with a synergistic regulation of ABA biosynthesis plays a crucial role in governing ABA signal production. Water stress induced a significant accumulation of ABA, which exhibited different patterns in detached and attached leaves. ABA catabolism followed a temporal trend of exponential decay for both basic and stress ABA, and there was little difference in the catabolic half-lives of basic ABA and stress ABA. Thus, the absolute rate of ABA catabolism, i.e. the amount of ABA catabolized per unit time, increases with increased ABA accumulation. From the dynamic processes of ABA biosynthesis and catabolism, it can be inferred that stress ABA accumulation may be governed by a synergistic regulation of all the steps in the ABA biosynthesis pathway. Moreover, to maintain an elevated level of stress ABA sustained activation of NCED3 should be required. This inference was supported by further findings that the genes encoding major enzymes in the ABA biosynthesis pathway, e.g. NCED3, AAO3 and ABA3 were all activated by water stress, and with ABA accumulation progressing, the expressions of NCED3, AAO3 and ABA3 remained activated. Data on ABA catabolism and gene expression jointly indicate that ABA signal production is controlled by a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism.     

Structure and function of Rac genes in higher plants

As the sole ubiquitous signal GTP-binding protein in higher plants, Rac genes act as pivotal molecular switches and participate in regulations of many life activities, such as cell morphogenesis and polarity growth, programmed cell death, production of H2O2, cell differentiation, and hormone reaction. Based on our work on rice Rac genes, this paper summarizes the researches on Rac genes in higher plant of the last ten years. It will help us to understand the relation between the signal tranduction and the biological functions of plant Rac.     

Transitional function of DG to CA3 in the hippocampus

Using single cell channel model, the transmission features of CA3-DG network in the hippocampus are investigated. The influence of the stimulation on discharge pattern of pyramidal neurons is analyzed, which shows that it starts with period spiking discharges, followed by period-doubling bifurcation to chaos, and period 3 discharge evolving into chaos, and ultimately a period of bursting discharges. By the synaptic model, the CA3-DG network model is constructed, which analyzes the summation of postsynaptic currents in the network, the influence of postsynaptic current on discharge rhythm as well as the mechanism of bursting discharges. The strong capacity of spatiotemporal encoding in the network indicates the features of CA3 network during the information transmission process in the hippocampus. The modeling result with time delay of the synaptic transmission is in accordance with the experimental phenomena of action potential in the hippocampus.     

Simulation study and function analysis of the dynamic aortic valve

The dynamic aortic valve (DAV) is a new left ventricular assist device, a micro-axial blood pump implemented at the position of the aortic valve, pumping blood from the left ventricle into the aortic artery. The present dynamic aortic valve operates at 7 different rotation speeds, ranging from 3000 r/min (speed 1) to 9000 r/min (speed 7). Because in vivo experiments need a lot of live animals and take a long period of time, modeling and simulation have been widely used to simulate and analyze hydra-dynamic property of the DAV and its assisting effects. With the measurements from the mock circulatory loop, a mathematic model of the DAV is established and embedded into the previously developed canine circulatory system. Using this model, the effect of the DAV on the failing heart at each rotation speed level is investigated. The vital cardiac variables are computed and compared with in vivo experimental results, which are in good agreement with an acceptable difference mostly 15%. The establishment of the DAV model and its simulation are useful for further improvement of the DAV device.     

Interacting domains of the HN and F Proteins of paramyxovirus

Binding sialates to hemagglutinin-neuraminidase （HN） activates （triggers） the fusion protein （F） to start the membrane fusion process of paramyxovirus, but the mechanism by which the HN and F associate with each other to induce membrane fusion is still unclear. It is noteworthy to study the interaction domains of HN and F of paramyxovirus. To screen interacting domains of the HN and F proteins of Avian parainfluenza virus-2 （APIV-2） and identify the structure of binding proteins, the GST pull-down assay and mass spectroscopy （MS） and circular dichroism （CD） experiments were performed in this study. The study revealed that the globular head region of HN protein tends to form a complex with either the heptad repeat 1 （HR1） or the heptad repeat 2 （HR2） of F protein respectively. This paper discusses the novel fusion mechanism induced by paramyxovirus HN and F proteins.     

The expression and function of VEGF at embryo implantation “window” in the mouse

Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen that plays a critical role in angiogenesis. Recent reports indicated that VEGF was closely involved in embryo implantation and embryonic vasculogenesis. However, very little information is available about the detailed expression and function of VEGF at implantation “window”. In this work, VEGFs were primarily present on uterine epithelial cell monolayer and blastocysts including the outgrew trophoblasts at implantation window. VEGF antibodies decreased the number of mice embryos implanted and the percentage of blastocysts with attachment and outgrowth in a co-culture model in a dose-dependant manner. These findings demonstrate that VEGF is one of the essential cytokines for embryo implanta-tion in mouse. VEGF may act as a local mediator to regulate the maternal-fetal interaction, and facilitate blastocyst implantation.     

Photometric modeling of the Moon using Lommel-Seeliger function and Chang’E-1 IIM data

The imaging intefferometer （IIM） aboard the Chang＇E-1 lunar orbiter is the first multispectral imaging spectrometer for Chinese lunar missions. Before science applications （e.g., FeO and TiO= mapping） of the IIM raw data, the radiance variation due to changes in illumination and viewing geometry has to be removed from the radiometrically calibrated IIM Level 2A images. To achieve this, we fit the IIM Level 2A radiance data with a Lornmel-Seeliger photometric model consisting of an exponential term and a fourth order polynomial in the phase function, without distinguishing between lunar maria and highlands. The exponential and the fourth order polynomial parameters are derived separately by fitting to two datasets divided at a solar phase angle threshold, avoiding a decrease in the phase function close to zero phase angle. Different phase angle thresholds result in coincident fitting curves between 20° and 75°, while large discrepancies occur at other phase angles. Then the derived photometric model is used to normalize the IIM Level 2A data to radiance values at an incidence and phase angle of 30° and emission angle of 0°. Our photometric model is validated by comparing two photometrically normalized IIM radiance spectra covering the same areas, showing a relative deviation consistent with the IIM preflight calibration.     

Establishment of widely expressed<Emphasis Type="Italic">hb1f</Emphasis> transgenic mouse lineage and its morphologic analysis

Human nuclear receptor hB1F is a novel member of the fushi tarazu factor Ⅰ subfamily of nuclear receptor superfamily. The studies about its homologous genes indicate that hB1F may play a key role in regulating the metabolic homeostasis of cholesterol. After obtaining the founder mice carrying the trausgeue of hblf by microiujectiou, each founder was mated to normal C57 mouse and the positive F1 by PCR identification of the same founder were iutercrossed within sisters and brothers to establish the trausgeuic mouse lineage. The results of F1, F2 and offspring of test cross identification showed that the widely expressed hb1f trausgeuic mouse lineage was established successfully in this study. The tissue morphology of the trausgeuic lineage was also analyzed preliminarily.     

重组乙肝表面抗原结合蛋白(SBP)的制备及功能研究

先前的研究发现乙肝病毒表面抗原结合蛋白(Hepatitis B virus surface antigen binding protein,SBP)能够与乙肝病毒表面抗原结合并促进HBsAg与肝细胞的亲和性,为进一步探索该分子对免疫应答的调节功能,构建了表达载体pBV-SBP,并在E.coliDH5α中表达重组SBP.以Balb/c小鼠为试验对象,分为SBP试验组和对照组,首次注射乙肝疫苗21 d后,测定两组小鼠血清中抗乙肝疫苗抗体的效价.结果显示SBP试验组小鼠血清中抗乙肝疫苗抗体效价的平均值约为对照组的3.0倍(P<0.01),表明SBP能够显著提高乙肝疫苗的免疫效力,在试验期间Balb/c小鼠总体IgG水平未见显著变化.     

乙型肝炎病毒携带者孕妇与正常孕妇妊娠结局比较

目的探索妊娠合并乙肝病毒感染的妊娠结局及孕晚期肌注乙肝免疫球蛋白对预防乙肝病毒感染作用。方法对2003年11月至2004年11月本院孕产妇妊娠结局分析。结果(1)妊娠合并乙肝病毒感染者胎膜早破、胎儿窘迫、剖宫率升高;(2)对乙肝病毒携带者孕晚期肌注乙肝免疫球蛋白新生儿感染为8%,比文献报道低。结论妊娠合并乙肝病毒感染易发生胎膜早破、胎儿窘迫,使剖宫产率升高,孕晚期肌注乙肝免疫球蛋白,对预防乙肝病毒感染有一定作用。     

带His-tag的乙肝病毒融合抗原在毕赤氏酵母中的表达

乙肝病毒融合抗原SpreS1（简称SS1抗原）较S抗原有更强的免疫原性,可望有更好的临床应用前景．为了便于表达产物的纯化,利用化学合成的寡聚核苷酸链和PCR扩增,在SS1基因的5’端和3’端分别融合了6His-EK和6His的编码序列,将其重组质粒pPIC3.5k-6His-EK-SS1,pPIC3．5k-SS1-6His转化毕赤氏酵母菌GS115,筛选鉴定得到的重组酵母工程菌进行诱导培养,然后采用镍离子柱（Ni-NTA Basin）纯化表达产物,纯化的蛋白样品经ELISA效价测定、SDS-PAGE和Western Blot分析,结果表明融合抗原基因6His-EK-SS1和SS1-6His在毕赤氏酵母中均能表达,纯化的产物仍有免疫原性,所用的纯化方法简便有效．     

慢性乙型肝炎患者外周血CD45RA+,CD45RO+T淋巴细胞亚群的特点及临床意义

目的 探讨慢性乙型肝炎患者外周血CD4＋CD45RA＋，CD4＋CD45RO＋，CD8＋CD45RA＋和CD8＋CD45RO＋T淋巴细胞亚群的特点及及其与肝病病情的关系．方法 采集46例轻中度慢性乙型肝炎患者、58例重度慢性乙型肝炎患者和30例健康人的外周抗凝血，应用流式细胞技术三色荧光分析法对其外周血中CD4＋CD45RA＋，CD4＋CD45RO＋，CD8＋CD45RA＋和CD8＋CD45RO＋T淋巴细胞亚群进行检测，结果轻中、重度慢性乙型肝楚患者与正常人相比．其外周血中CD4＋，CD8＋T细胞均无明显改变；CD8＋CD45RA＋T细胞均明显降低，CD8＋CD45RO＋T细胞均明显增高，而CD4＋CD45RA＋，CD4＋CD45RO＋T细胞均无明显改变；重度慢性乙型肝炎患者与轻中度慢性乙型肝炎患者相比，CD8＋CD45RA＋T细胞明显降低（P〈0．05），CD8＋CD45RO＋T细胞明显升高（P〈0．05）．结论乙型肝炎慢性化过程中，CD8＋CD45RO＋T细胞起重要作用且与慢性乙型肝炎患者病情的进展呈正相关；检测CD4＋CD45RA＋．CD4＋CD45RO＋．CD8＋CD45RA＋和CD8＋CD45RO＋T淋巴细胞亚群比检测CD4＋和CD8＋T细胞亚群能使我们更加正确、充分、全面地了解慢性乙型肝炎的发病机制和预后，从而有效地指导临床治疗。     

首都师范大学新生HBsAg携带情况调查分析

本文对我校１９９４年外地４６５名新生作乙型肝炎表面抗原及肝功能坚携带情况作了初步探讨分析，结果男生高于女生，农村学生高于城市学生，南方省市地区高于其它省市地区。并对其原因及防治措施进行了讨论。     

乙型病毒性肝炎数学模型及其控制

针对乙型肝炎病毒的传播方式以及各种状态间的转化模式,建立由微分方程表达的乙型肝炎数学模型.分析表明,如果该模型有正平衡点,则疾病消除点不稳定,此时该传染病将会蔓延,因此应对疾病实施有效控制:在采取母婴阻断和新出生婴儿免疫控制方法的基础上,再对易感人群施加免疫控制.构造出一个Lyapunov函数,应用Lyapunov稳定性理论,证明了施加上述控制后,该传染病模型在疾病消除点全局渐近稳定,即乙肝病毒最终可以灭绝,并得出了乙肝病毒最终消除的免疫条件.     

SRAP标记遗传距离与小麦F1产量相关性的研究

为探讨利用小麦亲本间遗传距离预测F1产量的可行性,以大田农艺性状表现优良的36个小麦品系配成50个组合为材料,研究SRAP分子标记遗传距离(GD)与50个杂交组合的F1产量的相关性.结果表明:分子标记距离与全部杂交组合F1产量相关程度低,但分析各区组内的相关关系时,存在高度正相关.当不改变母本的各组合中,GD与F1产量之间相关关系数在05以上的占786%;当不改变父本的各组合中,GD与F1产量之间相关关系数在0.5以上的占56.3%.