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91.
β1,3-N-乙酰氨基葡萄糖转移酶-2,-8(β3GnT-2, β3GnT-8)共同参与多聚N-乙酰氨基乳糖([Galβ1→4GlcNAcβ1→3]n)的合成,从而使得细胞表面的相应糖链结 构延长进而影响细胞的恶性转化.已有研究表明,在全反式维甲酸诱导人白血病细胞株 HL-60分化过程中β3GnT-2,-8的表达上调,但其分子机制不明.本文旨在探讨ATRA诱导 HL-60分化过程中,转录因子Ets-1对β3GnT-2,-8表达调控的分子机制.采用10-6 mol/L ATRA 诱导人白血病细胞株HL-60向粒系分化,RT-PCR检测到细胞中Ets-1的表达 明显增加;进一步采用染色质免疫沉淀(ChIP)结合电泳迁移率变动实验(EMSA)检测 证实,有活化的Ets-1结合至β3GnT-2/-8基因调控区. 以上结果表明,转录因子Ets-1对 人白血病细胞株HL-60分化过程中β3GnT-2,-8基因有表达调控作用. 相似文献
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无血清无饲养层条件下培养小鼠胚胎干细胞 总被引:2,自引:0,他引:2
目的研究在无血清无饲养层条件下小鼠胚胎干细胞的培养方法,为最终建立无血清无饲养层培养系统打下基础。方法比较小鼠胚胎干细胞ES-S8株在无血清培养体系和有血清培养体系中的生长情况,分析ES-S8细胞克隆形成效率,测定其生长速度;然后在撤去血清和饲养层的条件下培养ES-S8细胞,进行AKP染色和表面标记物SSEA-1免疫荧光检测。结果ES-S8细胞在无血清培养条件下细胞生长速度减缓,克隆形成率降低,但AKP染色、SSEA-1免疫荧光均显阳性;在无血清无饲养层条件下ES-S8细胞培养仍能形成克隆,且AKP染色、SSEA-1免疫荧光均显阳性。结论研究表明ES-S8细胞能够在无血清无饲养层的培养条件下生长,保持其良好的未分化特性。 相似文献
94.
Reproduction diversity of Enteromorpha prolifera 总被引:1,自引:0,他引:1
Enteromorpha prolifera (Muell.) J. Agardh (Chlorophyta, Ulvophyceae), which is distributed widely in the Inter-tidal zone of the ocean, is one of the most common fouling green algae. However, the present understandings of the life history of E. prolifera have been insufficient to explain their seasonal abundances. Thus it is essential to investigate how many.reproductive strategies are likely to contribute to the successful colonization and flourishing of the green alga. In the present study the reproduction diversity of E. prolifera was observed and studied systematically by culturing chopped tissues. Our results showed that there are in total seven pathways of reproduction for E. prolifera including sexual, asexual and vegetative reproduction. It was Indicated that the variety of the reproductive ways and the large quantity of reproductive cells produced and released during the reproductive season are the two key factors that facilitate colonization of E. prolifera. The reproduction of the alga E. prolifera mainly depends on asexual methods. The results presented here contribute to increasing our understanding about how the opportunistic macroalgae successfully maintain colonization and excessive growth. 相似文献
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Linglan M Chao L Chunxiang Q Sitao Y Jie L Fengqing G Fashui H 《Biological trace element research》2008,122(2):168-178
Characterized by a photocatalysis property, nanoanatase is closely related to the photosynthesis of spinach. It could not
only improve light absorbance, transformation from light energy to electron energy, and active chemical energy, but also promote
carbon dioxide (CO2) assimilation of spinach. However, the molecular mechanism of carbon reaction promoted by nanoanatase remains largely unclear.
In this study, we report that the amounts of Rubisco activase (rca) mRNA in the nanoanatase-treated spinach were increased
by about 51%, whereas bulk-TiO2 treatment produced an increase of only 5%. Accordingly, the protein level of Rubisco activase from the nanoanatase-treated
spinach was increased by 42% compared with the control; however, bulk-TiO2 treatment resulted in a 5% improvement. Further analysis indicated that the activity of Rubisco activase in the nanoanatase-treated
spinach was significantly higher than the control by up to 2.75 times, and bulk-TiO2 treatment had no such significant effects. Together, one of the molecular mechanisms of carbon reaction promoted by nanoanatase
is that the nanoanatase treatment results in the enhancement of rca mRNA expressions, protein levels, and activities of Rubisco
activase, thereby leading to the improvement of Rubisco carboxylation and the high rate of photosynthetic carbon reaction. 相似文献
97.
Ce3+ in various concentrations was added to superoxide dismutase (SOD) from rat eryhrocyte in vitro to gain insight into the mechanism
of molecular interactions between Ce3+ and SOD. The results showed that the reaction between SOD and Ce3 was two order, which meant that the SOD activity was markedly accelerated by a low concentration of Ce3+ and inhibited by a high concentration of Ce3+. The spectroscopic assays suggested that the Ce3+ was determined to directly bind to SOD; the binding site of Ce3+ to SOD was 0.96, and the binding constants (K
A) were 6.78 × 105 and 1.68 × 105L·mol−1; the binding Ce3+ entirely altered the secondary structure of SOD. It implied that the Ce3+ coordination created a new metal ion-active site form in SOD, thus leading to an enhancement in SOD activity. 相似文献
98.
Wei Zhou Jianyi Zhu Songdong Shen Shan Lu Jinfeng Wang Jianrong Xu Pu Xu 《Journal of applied phycology》2008,20(5):991-999
Nuclear divisions of carpospores, conchocelis and conchospores of Porphyra yezoensis, P. haitanensis, P. katadai var. hemiphylla and P. oligospermatangia from China were investigated. The observations showed diploid chromosome numbers of 2n = 6 for P. yezoensis and P. oligospermatangia, and 2n = 10 for P. haitanensis and P. katadai var. hemiphylla. For all four species, somatic pairing of chromosome sets was observed in late prophase. Sister chromosomes separated at
anaphase as mitosis took place in carpospores, conchocelis filamentous cells, conchosporangial branch cells and sporangial
cells (conchospore formation). Chromosome configurations of tetrad and ring-shaped in conchospore germination were observed,
demonstrating the occurrence of meiosis. The characteristics of diploid nuclear division in 2n = 6 species are the same as
those of 2n = 10 species. The influence of somatic pairing on nuclear division of diploid cells in Porphyra was discussed. 相似文献
99.
利用 DNA 同源重组技术使家蚕核型多角体病毒的多角体蛋白基因取代 v-cath 、 ChiA 两基因的部分编码区域和共同的启动子区域,获得了 v-cath 、 ChiA 两基因同时失活的、可形成多角体的、并能表达人粒细胞 - 巨噬细胞集落刺激因子的重组病毒 BmNPVpolh+CP-ChiA-GMCSF+. 研究结果显示: v-cath 、 ChiA 两基因的失活不影响病毒的复制及多角体的形成,但感染细胞的存活时间比野生病毒感染的多 2 天,可明显改善外源基因在培养细胞和家蚕中的表达水平;感染 BmNPV polh+CP-ChiA-GMCSF+的家蚕幼虫体表保持正常,无野生病毒感染后引起的破皮流脓现象 . 相似文献
100.
《Inorganica chimica acta》2001,312(1-2):245-248
The structure of the title compound has been determined by X-ray diffraction at 190 K. The complex has an all trans configuration with an elongated tetragonally distorted octahedral CuO6 chromophore. The elongated axis corresponding to the trans-Cu–O(ether) bonds. The ligand molecules are bidentate via the carboxyl and the 3-ether O atoms; the 6-ether O atoms are not coordinated and are remote from the Cu centres. The bond lengths to the Cu centres are Cu–O(ether) 2.355 Å, Cu–O(Carboxyl) 1.933 Å and Cu–OH2 1.995 Å.The EPR spectrum of both the powder and frozen solution forms is typical of a rhombic system with a dx2−y21 electronic configuration. There were no significant differences in spectra recorded over the temperature range 77 K to room temperature. These results are discussed in relation to earlier published results on closely related oxa-carboxyl complexes. 相似文献