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991.
992.
Analysis of 16 flavonoids and 3 other phenols in 177 samples of the genus
Rhododendron was carried out by HPTLC silica gel plate-stepwise development and
polyamide thin layer. The result reveals that the presence of monoglycosides of quercetin is a
general character of flavonoids in the Chinese rhododendrons; some taxa are characterized by
presence or absence of certain glycosides; although myricetin, and gossypetin are generally
rare in this genus, they are concentrated in some taxa, and therefore they are valuable in
chemotaxonomy. The significance of quantitative and semi-quantitative assessment of chem-ical characters for chemotaxonomy of Rhododendron is also discussed. 相似文献
993.
Lepidophylloides sp. and Saportaea cf. nervosa Halle were found in the Permian coal bearing strata (Lower Shihhotse Formation) from Huaibei coal field, Anhui, China. Lepidophylloides sp., leaves are linear. The longest one is more than 13cm in length. The specimens obtained show about 3–16mm width with single vein. The epidermal cells are re. ctangular with smooth walls. Stomata align in regular rows, widely spread, particularly, in the lower cuticle. Saportaea cf. nervosa Halle The lamina stomata composed of two reniform guard cells are slightly sunken, the lamina of Saportaea of. nervosa Halle is in broal shoveled shape with 5.6 cm in length, and 6.5 cm in width. Petiole is 1.6cm in length and about 8mm in width. At the upper end of the petiole, it divides into two branches. The veins appear from the branches of the petiole and divide by repeated dichotomy. In the upper part of the lamina, the veins become numerous (about 13 per centimetre). The epidermal cells are elongated polygonat to polygonal, with smooth walls. Stomata surrounded by 5-8 subsidiary cells. 相似文献
994.
he changes of Mn2+ contents in Anabaena variabilis were probed by EPR. Treatments with CaCl2 and Ca (NO3)2 at high concentrations induced the release of bound Mn and the decrease of oxygen-evolving activity of the cyanobacterium. When the release percentage of bound Mn reached up to 57%, the oxygen-evolving activity decreased to zero. MgCl2 treatment resulted in less effectiveness than CaCl2 MnCl2 at high concentration inhibited cyanobacterial oxygen evolution, as the indication of EGTA. In the comparision with control the low temperature fluorescence emission spectra of the cyanobacterium treated by CaCl2, MgCl2 and MnCl2 changed with the shoulder disappearance at 686 nm and the decline of ratio of F730/F695 The possible competitive substitutions among ions at their binding sites in oxygen-evolving complex were discussed. 相似文献
995.
996.
The Impact of Genetic Removal of GFAP and/or Vimentin on Glutamine Levels and Transport of Glucose and Ascorbate in Astrocytes 总被引:12,自引:0,他引:12
Pekny Milos Eliasson Camilla Siushansian Ramin Ding Mei Dixon S. Jeffrey Pekna Marcela Wilson John X. Hamberger Anders 《Neurochemical research》1999,24(11):1357-1362
The importance of the intermediate filament (IF) proteins glial fibrillary acidic protein (GFAP) and vimentin for astrocyte function was studied by investigating astrocytes prepared from GFAP-/-and/or vimentin-/- mice. The rate of glucose uptake through facilitative hexose transporters was not affected by depletion of GFAP or vimentin. Similarly, the absence of these IF proteins did not affect ascorbate uptake, under control or cyclic AMP-stimulated conditions, or ascorbate efflux through volume-sensitive organic anion channels. However, compared with wild-type astrocytes, glutamine concentrations were increased up to 200% in GFAP-/- astrocytes and up to 150% in GFAP+/-astrocytes and this increase was not dependent on the presence of vimentin. GFAP-/- astrocytes in culture still contain IFs (made of vimentin and nestin), whereas GFAP-/-vim-/- cultured astrocytes lack IFs. Thus, glutamine levels appear to correlate inversely with GFAP, rather than depend on the presence of IFs per se. Furthermore, the effect of GFAP is dose-dependent since the glutamine concentration in GFAP+/- astrocytes falls between those in wild-type and GFAP-/-astrocytes. 相似文献
997.
土壤水分含量的理论分析及预测模型 总被引:5,自引:0,他引:5
本文应用物理学中的电介质和电磁理论,分析和研究土壤的组成成分,得到了反映土壤水分含量的理论表达式,并在自行研制的测试仪器上,对相关变量进行测量,由此建立了土壤水分含量的预测模型,统计检验和国代结果显示了理论模型和预测模型的合理性. 相似文献
998.
从紫果西番莲(Pasifloraedulis)、杂交种西番莲(P.edulisXP.edulisvar.flavicarpa)、黄果西番莲(P.edulisvar.flavicarpa)、转心莲(P.caerulea)及龙珠果(P.foetida)分离到的5个黄瓜花叶病毒(CMV)分离物(PE、PE2、PEf、PC、PF)所作的生物学性质、理化特性和血清学关系的比较研究结果表明,5个分离物在寄主反应及血清学性质上存在不同,而在病毒粒体形态、体外抗性、蚜虫传毒和病毒外壳蛋白分子量方面无明显差异。根据5个分离物的寄主反应和血清学关系,可将其区分为CMV的两个亚组,其中PE、PE2、PC和PF属CMV亚组I,PEf属CMV亚组I。 相似文献
999.
1000.
Qian Wang Jin Liu Josephine M Janssen Francesca Tasca Hailiang Mei Manuel A F V Gonalves 《Nucleic acids research》2021,49(20):11986
Prime editing is a recent precision genome editing modality whose versatility offers the prospect for a wide range of applications, including the development of targeted genetic therapies. Yet, an outstanding bottleneck for its optimization and use concerns the difficulty in delivering large prime editing complexes into cells. Here, we demonstrate that packaging prime editing constructs in adenoviral capsids overcomes this constrain resulting in robust genome editing in both transformed and non-transformed human cells with up to 90% efficiencies. Using this cell cycle-independent delivery platform, we found a direct correlation between prime editing activity and cellular replication and disclose that the proportions between accurate prime editing events and unwanted byproducts can be influenced by the target-cell context. Hence, adenovector particles permit the efficacious delivery and testing of prime editing reagents in human cells independently of their transformation and replication statuses. The herein integrated gene delivery and gene editing technologies are expected to aid investigating the potential and limitations of prime editing in numerous experimental settings and, eventually, in ex vivo or in vivo therapeutic contexts. 相似文献