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991.
对培养15,25和35d的新疆紫草培养细胞的电镜观察结果表明:紫草素的合成部位在内质网上;色素颗粒通过两种方式分泌到细胞外,一是与细胞膜融合,通过细胞壁释放到细胞外,二是通过细胞裂解大量排出细胞外。不产色素细胞的生长和结构变化情况与产色素细胞都相类似,只是未见大量的色素颗粒。 相似文献
992.
取材于妊娠终止胚胎生殖腺或生殖嵴及其周围组织,用DMEM+NCS培养液体外培养,分离由人PGCs转化成的类ES细胞,并将其与同源胚胎成纤维细胞一起用胰蛋白酶+EDTA的无钙镁PBS液消化传代。在原代培养12h观察到胞体较大、边缘不整、贴壁分裂增殖的PGCs样细胞,48h后观察到26处紧密排列呈鸟巢状的类ES细胞集落及集落团。第6d传代成功,第16d传至第4代。结果表明,体外培养附植后胚胎能够建成人的类ES细胞系。 相似文献
993.
994.
High oxalate consumption has been recognized as a risk factor for renal calcium oxalate stones in companion animals (dogs and cats). However, the cellular signaling involved in oxalate-induced dysfunction in renal tubular epithelial cells remains not fully elucidated. In this study, Mardin–Darby canine kidney (MDCK) cells, an epithelial cell line derived from canine kidney tubule, were tested for cell proliferation activity and barrier function after being exposed to sodium oxalate (NaOx). Further, the involvement of Wnt/β-catenin in NaOx-induced renal epithelial barrier dysfunction was evaluated. MDCK cells treated with NaOx exhibited reduction in cell proliferation and migration. Besides, NaOx exposure led to a decrease in transepithelial electrical resistance and an increase in paracellular permeability. The deleterious effects of NaOx on epithelial barrier function were related to the suppressed abundance of tight junction proteins including zonula occludens, occludin, and claudin-1. Of note, protein levels of β-catenin and phosphorylated (p)-β-catenin (Ser552) in MDCK cells were repressed by NaOx, indicating inhibitory effects on Wnt/β-catenin signaling. An inhibition of glycogen synthase kinase-3β (GSK-3β) by SB216763 enhanced the abundance of β-catenin and p-β-catenin (Ser552), and protected against epithelial barrier dysfunction in NaOx-treated MDCK cells. The results revealed a critical role of Wnt/β-catenin signaling in the epithelial barrier function of MDCK cells. Activation of Wnt/β-catenin signaling might be a potential therapeutic target for the treatment of oxalate-linked renal stones. 相似文献
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996.
Bacterial cells may be immobilized in soil through adsorption to a variety of soil particles. These associations affect the
interaction of native soil microbes with their nutrient sources and control at least in part the distribution of foreign bacteria
entering the soil system. To observe the relationship between soil structure and adsorption of amended bacterial cells, a
series of intact cores of Freehold fine sandy loam were inoculated with suspensions of Arthrobacter crystallopoietes cells at concentrations ranging from 106 to 108 cells per ml. The cells were cultivated in a glucose-based medium to induce spherical cell formation. Following inoculation,
the soil cores were rinsed with sterile water (30–40 ml h–1), flushed with thiazine red R to stain the bacterial cells, and then prepared for examination by common micromorphological
techniques. The use of fluorescence, polarizing, and reflected light microscopy of soil thin sections, allowed direct, qualitative
determinations of microbial distribution and associations with soil components. A. crystallopoietes cells were detected throughout the length of the soil columns. Soil pores did not appear to be clogged by the spherical A. crystallopoietes cells. Adsorption of amended bacteria was governed by the presence of both variably charged mineral oxides and organic matter
within the intergrain microaggregates and occurred along coated mineral surfaces. Amendment of non-inoculated soil columns
with 0.2% (w/v) solution of glucose demonstrated that the staining and sectioning procedure was sufficiently sensitive to
detect growth of indigenous bacterial populations and their distributions within the soil matrix.
Received; 6 April 1997 相似文献
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998.
连云鹏 《广西农业生物科学》1999,18(4):287-290
从室温下存放2 年以上的紫色非硫光合细菌的培养液中分离出PNSB菌株C。对该菌株的生物学特性、内光合膜结构和细胞的不对称分裂方式进行了研究。菌株C细胞中含有细菌叶绿素a。具有层状并与细胞质膜平行的内光合膜系统。细胞横切面显示内光合膜系统呈环形复瓦状结构。细胞纵横切面显示内光合膜是一完全的整体。菌株C以细胞的不对称分裂方式进行繁殖, 并以细胞的缢缩完成分裂。据此, 菌株C被鉴定为红假单胞菌属 (Rhodopseudom onas) 的成员。 相似文献
999.
木材细胞壁的构造及其主成分的堆积过程 总被引:3,自引:2,他引:1
赵广杰 《北京林业大学学报》1999,21(1):72-79
该文对有关木材细胞壁构造和木材细胞壁形成过程的主要研究做了归纳,尤其是对木质部形成和分化机理,木材细胞壁主成分的堆积过程的最新研究成果做了比较详细的介绍.这些研究对于我们清理迄今为止在木材构造方面的研究工作,确定21世纪中国木材解剖学研究方向有一定帮助和借鉴 相似文献
1000.