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1.
Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper
culture conditions, which is designated as totipotency. As a result, plant cells can easily regenerate new tissues or organs
from a wide variety of explants. However, the mechanism by which plant cells have such remarkable regeneration ability is
still largely unknown. In this study, we used a set of meristem-specific marker genes to analyze the patterns of stem cell
differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro. Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis. 相似文献
2.
A recombinant cell line (NIH3T3:pLtkSN) was made by infecting parental cells (NIH3T3) with a recombinant retrovirus (pLtkSN) encoding herpes simplex virus thymidine kinase (HSVtk) gene. The cells expressing HSVtk (NIH3T3:pLtkSN) grew 2.3 times more than the parental cells (NIH3T3) in Dulbecco's Modified Eagles Media containing 10% (v/v) horse serum. The NIH3T3:pLtkSN cells also showed a significant enhancement in the maximal cell concentration and the specific growth rate even at 2.5% serum concentration. The specific O2 uptake rate of NIH3T3 was 2.1 times greater than that of NIH3T3:pLtkSN. Under both O2-limited and O2-unlimited conditions, it appears that HSVtk plays an important role in enhancing the growth characteristics of animal cells. 相似文献
3.
Xiao-Guo Xiang Wei-Tao Jin De-Zhu Li André Schuiteman Wei-Chang Huang Jian-Wu Li Xiao-Hua Jin Zhen-Yu Li 《PloS one》2014,9(1)
Collabieae (Orchidaceae) is a long neglected tribe with confusing tribal and generic delimitation and little-understood phylogenetic relationships. Using plastid matK, psaB, rbcL, and trnH-psbA DNA sequences and morphological evidence, the phylogenetic relationships within the tribe Collabieae were assessed as a basis for revising their tribal and generic delimitation. Collabieae (including the previously misplaced mycoheterotrophic Risleya) is supported as monophyletic and nested within a superclade that also includes Epidendreae, Podochileae, Cymbidieae and Vandeae. Risleya is nested in Collabiinae and sister to Chrysoglossum, a relationship which, despite their great vegetative differences, is supported by floral characters. Ania is a distinct genus supported by both morphological and molecular evidence, while redefined Tainia includes Nephelaphyllum and Mischobulbum. Calanthe is paraphyletic and consists four clades; the genera Gastrorchis, Phaius and Cephalantheropsis should be subsumed within Calanthe. Calanthe sect. Ghiesbreghtia is nested within sect. Calanthe, to which the disputed Calanthe delavayi belongs as well. Our results indicate that, in Collabieae, habit evolved from being epiphytic to terrestrial. 相似文献
4.
5.
Jianhua Zhang Mei Liu Hongjian Jin Liandong Deng Jinfeng Xing Anjie Dong 《AAPS PharmSciTech》2010,11(2):894-903
Lactate esters are widely used as food additives, perfume materials, medicine additives, and personal care products. The objective
of this work was to investigate the effect of a series of lactate esters as penetration enhancers on the in vitro skin permeation of four drugs with different physicochemical properties, including ibuprofen, salicylic acid, dexamethasone
and 5-fluorouracil. The saturated donor solutions of the evaluated drugs in propylene glycol were used in order to keep a
constant driving force with maximum thermodynamic activity. The permeability coefficient (K
p), skin concentration of drugs (SC), and lag time (T), as well as the enhancement ratios for K
p and SC were recorded. All results indicated that lactate esters can exert a significant influence on the transdermal delivery
of the model drugs and there is a structure-activity relationship between the tested lactate esters and their enhancement
effects. The results also suggested that the lactate esters with the chain length of fatty alcohol moieties of 10–12 are more
effective enhancers. Furthermore, the enhancement effect of lactate esters increases with a decrease of the drug lipophilicity,
which suggests that they may be more efficient at enhancing the penetration of hydrophilic drugs than lipophilic drugs. The
influence of the concentration of lactate esters was evaluated and the optimal concentration is in the range of 5∼10 wt.%.
In sum, lactate esters as a penetration enhancer for some drugs are of interest for transdermal administration when the safety
of penetration enhancers is a prime consideration. 相似文献
6.
7.
Xiao LiWei Xing Shuping Zhuo Jin ZhouFeng Li Shi-Zhang QiaoGao-Qing Lu 《Bioresource technology》2011,102(2):1118-1123
Series of nanoporous carbons are prepared from sunflower seed shell (SSS) by two different strategies and used as electrode material for electrochemical double-layer capacitor (EDLC). The surface area and pore-structure of the nanoporous carbons are characterized intensively using N2 adsorption technique. The results show that the pore-structure of the carbons is closely related to activation temperature and dosage of KOH. Electrochemical measurements show that the carbons made by impregnation-activation process have better capacitive behavior and higher capacitance retention ratio at high drain current than the carbons made by carbonization-activation process, which is due to that there are abundant macroscopic pores and less interior micropore surface in the texture of the former. More importantly, the capacitive performances of these carbons are much better than ordered mesoporous carbons and commercial wood-based active carbon, thus highlighting the success of preparing high performance electrode material for EDLC from SSS. 相似文献
8.
Zenghui Hu Yingbai Shen Fanyi Shen Youqing Luo Xiaohua Su 《Trees - Structure and Function》2009,23(5):1003-1011
Interplant communication has been widely demonstrated in plants, especially in herbaceous plants. In this study, mechanical
damage was shown to affect the levels of pyrochatechol, chlorogenic acid, gallic acid and p-hydroxyl benzoic acid in poplar (Populus simonii × P. pyramidalis ‘Opera 8277’) cuttings, indicating the activation of defense response. In neighboring intact cuttings, the levels of those
phenolics also varied when compared to the control, suggesting the interplant communication between poplar cuttings. Three
volatiles, methyl jasmonate, methyl salicylate and benzothiazole, were detected in volatiles emitted from mechanically damaged
poplar cuttings. All of them can induce changes in the levels of four phenolics. Therefore, they could act as airborne signals
between P. simonii × P. pyramidalis ‘Opera 8277’ cuttings. The different change patterns of phenolic contents induced by different volatiles imply that the defense
response activated in neighboring plants may be regulated by multiple signaling pathways. The results also suggest that the
entire defense response of plants involves a variety of airborne signals in wound-induced volatiles. 相似文献
9.
10.
Shaohui Ji Lifang Jin Xiangyu Guo Weizhi Ji 《In vitro cellular & developmental biology. Animal》2010,46(8):693-701
Studies with hepatic progenitor cells from non-human primates would allow better understanding of their human counterparts. In this study, rhesus monkey liver epithelial progenitor cells (mLEPCs) were derived from a small piece of newborn livers in chemical defined serum-free medium. Digested hepatic cells were treated in Ca2+-containing medium to form cell aggregates. Two types of cell aggregates were generated: elongated spindle cells and polygonal epithelial cells. Elongated spindle cells were expressed as vimentin and brachyury, and they were disappeared within 5 d in our cultures. The remaining type consisted of small polygonal epithelial cells that expressed cytokeratin 7 (CK7), CK8, CK18, nestin, CD49f, and E-cad, the markers of hepatic stem cells, but were negative for α-fetoprotein, albumin, and CK19. They can proliferate and be passaged, if on laminin or rat tail collagen gel, to initiate colonies. When cultured with dexamethasone and oncostatin M, the expression of mature hepatocyte markers, such as α-1-antitrypsin, intracytoplasmic glycogen storage, indocyanine green uptake, and lipid droplet generation, were induced in differentiated cells. If transferred onto mouse embryonic fibroblasts feeders, they gave rise to CK19-positive cholangiocytes with formation of doughnut-like structure. Thus, mLEPCs with bipotency were derived from newborn monkey liver and may serve as a preclinical model for assessment of cell therapy in humans. 相似文献