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921.
滋养层细胞凋亡调控的研究 总被引:1,自引:0,他引:1
胎盘滋养层是母体与胎儿之间进行氧气、营养物质和代谢物交换的组织。大量研究证实 ,滋养层细胞凋亡是正常妊娠过程中存在的一种生理现象 ,具有重要的生理意义。滋养层细胞的凋亡受到Bcl 2家族蛋白、Fas FasL系统、p5 3蛋白及细胞因子等多种因素的调控。本文主要介绍滋养层细胞凋亡的调控及滋养层细胞凋亡与妊娠相关疾病的研究进展。 相似文献
922.
Summary. In an effort to gain a greater understanding of nectar production, we studied the dynamic mechanisms of starch accumulation and transformation and nectar transportation in the Cucumis sativus L. female flower. Starch, which is the main precursor of nectar, accumulates in the epidermis and underlying parenchyma, with the most active accumulation occurring in the parenchyma cells within 3 days prior to anthesis. Thereafter, the starch was successively hydrolyzed and the hydrolyte was transported from the amyloplasts to vacuoles, suggesting that amyloplasts and vacuoles are the centers of nectar production. In addition, we observed few plasmodesmata and the presence of invaginated plasmalemma and electron-dense material in the intercellular spaces, suggesting that the apoplast system is involved in nectar transportation in an ATPase-dependent fashion.Correspondence and reprints: College of Life Sciences, Peking University, Beijing, 100871, Peoples Republic of China 相似文献
923.
Xiaoyan L Yi L Peng L Songsheng Q Ziniu Y 《Journal of biochemical and biophysical methods》2004,59(3):267-274
A novel microcalorimetric technique based on the bacterial heat output was applied to evaluate the special growth model, the protein expression and the generation time of Bacillus thuringiensis for the first time. The thermogenic curves of the aerobic metabolism of B. thuringiensis strains YBT-833, YBT-1520 and YBT-833-2-1 were determined by using an LKB-2277 BioActivity Monitor. The analysis of the thermogenic curves indicated both the mutant strain and the wild-type strains followed the same linear growth model during sporulation. The metabolism heat output revealed heat output was correlated to the yield of the insecticidal crystal proteins (ICPs) very well, the more protein product, and the less heat output. Based on the data acquired, we proposed that this method could be a useful tool in monitoring the fermentation of B. thuringiensis. 相似文献
924.
A universal primer PCR (UPPCR) combined with denaturing gradient gel electrophoresis (DGGE) was evaluated as a method permitting the rapid detection of pathogens. The results show that this method is efficient at amplifying the conserved regions of bacterial 16S rRNA genes with universal primers and can detect causative bacterial pathogens rapidly. Six species of bacteria from fisheries (Pseudomonas fluorescens, Vibrio anguillarum, Aeromonas hydrophila, Vibrio fluvialis, Providencia rettgeri and Aeromonas sobria) were examined. Our results indicate that the approach we undertook can be adopted not only for axenic bacterial populations but also for mixed communities as well. Furthermore, we were able to achieve the rapid detection of multiple bacteria a single in sample. In addition, UPPCR-DGGE was shown to be better than previously reported UPPCR-single-stranded conformation polymorphism (SSCP)-based methods for the rapid detection of bacterial pathogens. 相似文献
925.
Guo T Adang AE Dong G Fitzpatrick D Geng P Ho KK Jibilian CH Kultgen SG Liu R McDonald E Saionz KW Valenzano KJ van Straten NC Xie D Webb ML 《Bioorganic & medicinal chemistry letters》2004,14(7):1717-1720
Potent small molecule biaryl diketopiperazine FSH receptor agonists such as 10c (EC(50)=13 nM) and 11f (EC(50)=1.2 nM) were discovered through the design, synthesis and evaluation of three biaryl diketopiperazine optimization libraries with over 300 compounds. These libraries were prepared via solid-phase parallel synthesis using a cyclization-release method. 相似文献
926.
Xia P Yin ZJ Chen Y Zhang Q Zhang B Xia Y Yang ZY Kilgore N Wild C Morris-Natschke SL Lee KH 《Bioorganic & medicinal chemistry letters》2004,14(12):3341-3343
Two 1-thia-DCK analogues (9a and 9b) were synthesized and evaluated for inhibition of HIV-1 replication in H9 lymphocytes. Compound 9a showed excellent anti-HIV activity with an EC(50) value of 0.00012 microM and therapeutic index of 1408000. Compound 9b was less active with EC(50) and TI values of 3.11 microM and 62.3, respectively. The bioassay results indicated that thia-DCK analogues merit attention as potential HIV-1 inhibitors. 相似文献
927.
Zhang XL Liu M Xie P Wan S Tao Ye J Zhou X Wu J 《Bioorganic & medicinal chemistry letters》2004,14(14):3789-3792
We first synthesized N-pentafluorobenzyl-1-deoxynojirimycin (5F-DNM), one new derivative of 1-deoxynojirimycin (DNM). Effects on human peripheral blood mononuclear cells (PMBC) and secretion of cytokines from human PBMC by 5F-DNM were investigated. It was first found that 5F-DNM remarkably inhibited the secretion of interleukin-4 (IL-4) and had a specific inhibition on the expression of CD4 molecules. 5F-DNM, much less toxic than cyclosporin A, might be used as a new candidate of immunosuppressant for specifically treating Th2-mediated immune diseases. 相似文献
928.
In this study the chemical modification of paroxetine was employed to determine which structural differences between the paroxetine-like and femoxetine-like selective serotonin reuptake inhibitors is responsible for the differential potency of these agents in the inhibition of Staphylococcus aureus multidrug efflux pump systems. 相似文献
929.
Peng X Zhang A Kula NS Baldessarini RJ Neumeyer JL 《Bioorganic & medicinal chemistry letters》2004,14(22):5635-5639
A series of novel fluoroalkyl-containing tropane derivatives (6-8, 10-14, 17, and 18) were synthesized from cocaine. Novel compounds were evaluated for affinity and selectivity in competitive radioligand binding assays selective for cerebral serotonin (5-HT), dopamine (DA), and norepinephrine (NE) transporters (SERT, DAT, and NET). The nortropane-fluoroalkyl esters (7, 10, 11) were most potent for SERT (K(i): 0.18, 0.24, and 0.30 nM, respectively). Tosylate esters 17 and 18, synthesized as precursors for [(18)F]-labeled, Positron Emission Tomography (PET) imaging agents, also showed high affinity for DAT. 相似文献
930.
Beng?Ti?TeyEmail author Kok?Hoe?Yong Hong?Puay?Ong Tau?Chuan?Ling Swee?Tin?Ong Yan?Peng?Tan Arbakariya?Ariff Wen?Siang?Tan 《Biotechnology and Bioprocess Engineering》2004,9(5):374-378
The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed
(150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production ofEscherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at PH 7, 37°C and at a rotational speed of
250 rpm which is 0.927 h−1. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the
highest growth rate (0.927 h−1) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C.
The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of
the protein yield for theE. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher
compared to the lowest yield achieved, at 30°C. 相似文献