排序方式: 共有37条查询结果,搜索用时 15 毫秒
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研究了Chitosan(聚氨基葡糖)对红豆杉悬浮培养细胞PAL(苯丙氨酸解氨酶)活性及Taxol(紫杉醇)生物合成的影响.种胚来源的红豆杉细胞培养在改良MS液体培养基中,于培养的第18d添加不同浓度的Chitosan.Chitosan浓度为100~1000mg·L-1时对红豆杉细胞PAL活性有明显的诱导作用,且诱导作用随浓度的增加而增强,在诱导作用下PAL活性在16h达到峰值;Chitosan浓度在100mg·L-1时对红豆杉细胞的生长基本无抑制作用,增产效果最显著(约为对照组的10倍),Chitosan可作为Taxol合成的诱导子. 相似文献
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The first distinct mark of rodent implantation is the increased vascular permeability and significant angiogenesis at the
sites of blastocyst implantation, but its mechanism is not clearly defined. Vascular endothelial growth factor (VEGF) is the
key mediator for angiogenesis during embryogenesis and adult span and also serves as a vascular permeability factor. The aim
of this study is to explore VEGF regulation mechanism and the possible role that VEGF plays in implantation by studying the
VEGF expression and angiogenesis in the rat uterus during estrous cycle, ovarioectomized and peri-implantation stages usingin situ message RNA hybridization and confocal laser scanning techniques. The results indicated that VEGF was regulated by ovarian
steroid hormones. VEGF expression before implantation was localized at luminal epithelium, shifted to stroma as implantation
initiated and extensively located at the decidualizing stroma region after implantation. Bandeiraea simplicifolia-1 (BS-1)
agglutinin and antibody against von Willebrand factor (vWF) were used to mark the endothelial cells and blood vessels. The
results showed that the active angiogenesis occurred during the implantation process and this effect was probably mediated
by VEGF. The results suggest that under the regulation of ovarian steroid hormones, VEGF plays an essential role in angiogenesis
and increasing vascular permeability in endometrium, which are necessary for successful implantation. 相似文献
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Nan Zhang Peiheng Zhou Shifeng Zou Xiaolong Weng Jianliang Xie Longjiang Deng 《自然科学进展(英文版)》2014,24(2):128-133
In this paper, a dual-band mid-infrared metamaterial absorber was proposed to improve the energy absorption efficiency. Up to 99% absorption was obtained at 9.03 and 11.83 μm in the simulation, and each absorption band can be tuned by the dielectric spacing layer, i.e., the dielectric constant and its thickness. The dual-band absorption mechanism was analyzed, and the quite well absorption performance at large incident angles was also presented. The results of this study can be applied in the field of thermal absorbing and solar energy harvesting. 相似文献
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章龙江 《应用基础与工程科学学报》1995,(4)
本文将Lockhart-Martinelli关系式推广到水平管中的气体和非牛顿液体两相流动,得出了修正的L-M参数X.在内径为20.02和22.22mm的水平圆管中进行了压降,持液率和流型的实验研究,气相介质为空气,液相为聚丙烯酰胺(PAM)溶液,用修正的L-M参数X关联的压降和持液率的计算式与实验数据吻合较好。 相似文献
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中国红豆杉悬浮细胞固定化培养生产紫杉醇 总被引:2,自引:0,他引:2
对海藻酸钠包埋法固定中国红豆杉悬浮细胞的条件进行研究,建立了一套合适的固定化操作条件,即海藻酸钠浓度为30g/L,聚乙烯醇(PVA)浓度为80g/L,CaCl2浓度为20g/L,包埋密度为0.2kg/L,接种密度为0.1kg/L.在此基础上,对中国红豆杉细胞固定化培养的培养基进行了优化,结果表明,从红豆杉树皮中分离出的真菌培养物作为诱导物能限制细胞生长,且明显促进紫杉醇合成,并诱导紫杉醇分泌到培养液中.在培养基中适量地添加前体亦能提高紫杉醇的产量.对红豆杉细胞固定化培养中紫杉醇合成与分泌进行了动力学研究. 相似文献
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从油田注水联合处理站里分离得到的一株嗜热、耐酸、异养型硫酸盐还原菌,编号为CW-01.该菌株兼性厌氧、革兰氏阳性、有极生鞭毛、直或弯曲的短杆状,能产孢子.主要生理生化特性包括:生长pH范围为2.8~11,最佳生长pH为5~6.5,最佳生长盐度为1.3%,最佳生长温度37℃,在15~50℃下培养基中均能使测试瓶有黑色沉淀物产生.如果以硫酸盐为电子受体,则可以在乙酸盐、丙酸盐、乳酸盐、丙酮酸盐、丁酸盐、琥珀酸盐、苹果酸盐、延胡索酸盐、戊酸盐、己酸盐、庚酸盐、辛酸盐、癸酸盐、十三烷基酸盐、十五烷基酸盐、棕榈酸盐、十七烷基酸盐、酵母粉和乙醇等电子供体中生长,也能够利用葡萄糖、果糖作为唯一碳源生长.在乳酸盐为电子供体时,能够在硫酸钠、硫代硫酸钠、亚硫酸钠等电子受体中生长.从腐蚀防治的角度对该菌株的腐蚀速率、耐1227性质以及生长曲线也进行了测定.通过16s rDNA测序(GenBank上的AC号为:AY742958)以及系列比对分析:该菌属于细菌界(Bactetia)、厚壁菌门(Firmicutes)、梭菌纲(Clostridia)、梭菌目(Clostridiales)、蛋白胨链球菌科(Peptococcaceae)、脱硫肠状菌属(Desulfotomaculum),与该属中的种Desulfotomaculum putei相似性达到98%. 相似文献
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