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951.
You Li Eric S. Ho Samuel I. Gunderson Megerditch Kiledjian 《Nucleic acids research》2009,37(7):2227-2237
mRNA decapping is a critical step in the control of mRNA stability and gene expression and is carried out by the Dcp2 protein. Dcp2 is an RNA-binding protein that must bind the RNA in order to recognize the cap for hydrolysis. We previously demonstrated that a 60 nucleotide (nt) element at the 5′ end of the mRNA encoding Rrp41 is preferentially bound and decapped by Dcp2. Here, we demonstrate that enhanced decapping of this element is dependent on the structural integrity of its first 33 nt and not its primary sequence. The structure consists of a stem-loop positioned <10 nt from the 5′ end of the mRNA. The generality of a stem-loop structure in enhanced Dcp2-mediated decapping was underscored by the identification of additional potential Dcp2 substrate mRNAs by a global analysis of human mRNAs containing a similar predicted stem-loop structure at their respective 5′ end. These studies suggest a general role for 5′ stem-loops in enhancing decapping activity and the utilization of this structure as a predictive tool for Dcp2 target substrates. These studies also demonstrate that Dcp2 alone in the absence of additional proteins can preferentially associate with and modulate mRNA decapping. 相似文献
952.
953.
Fei You Ting Han Jing-zhong Wu Bao-kang Huang Lu-ping Qin 《Biochemical Systematics and Ecology》2009,37(3):162-165
Endophytes were isolated from roots of wild Rehmannia glutinosa to screen the strains with antifungal metabolites. A strain identified as Verticillium sp. was selected for chemical and biological investigations because of the strong antifungal activity of the crude extract against Pyricularia oryzae P-2b. Chemical investigations of culture broth afforded three compounds: 2,6-dihydroxy-2-methyl-7-(prop-1E-enyl)-1-benzofuran-3(2H)-one, massariphenone and ergosterol peroxide. The metabolites were isolated by silica gel and Sephadex LH-20, 2,6-dihydroxy-2-methyl-7-(prop-1E-enyl)-1-benzofuran-3(2H)-one was reported for the first time and the chemical structure was established following the analysis of NMR, UV, IR, MS data. 2,6-Dihydroxy-2-methyl-7-(prop-1E-enyl)-1-benzofuran-3(2H)-one and ergosterol peroxide displayed clear inhibition of the growth of three pathogens as well as Verticillium sp. 相似文献
954.
Lupei Du Minyong Li Qian Yang Yiqun Tang Qidong You Lin Xia 《Bioorganic & medicinal chemistry letters》2009,19(5):1477-1480
The combination of IKr and IKs blockade could lead to synergistic and safe class III anti-arrhythmic effect with the enhanced efficacy and reduced risk. On the rationale of structural hybridization of azimilide and HMR-1556, a novel series of IKr and IKs dual blockers were designed, synthesized and evaluated in vitro. One compound, 3r (CPUY11018), deserves further evaluation for its potent anti-arrhythmic activity and favorable cardiovascular profile. 相似文献
955.
A series of pyrazole-bridged heterometallic 3d-4f complexes, [CuDy(ipdc)2(H2O)4] · (2H2O)(H3O+) (1) and [CuLn(pdc)(ipdc)(H2O)4] · H3O+ (Ln = Ho (2), Er (3), Yb (4); H3ipdc = 4-iodo-3,5-pyrazoledicarboxylic acid; H3pdc = 3,5-pyrazoledicarboxylic acid), {[Cu3Ln4(ipdc)6(H2O)16] · xH2O}n (Ln = Sm (5), x = 8.5; Ln = Eu (6), x = 7; Ln = Gd (7), Tb (8), x = 9), have been synthesized and structurally characterized. Ligand H3ipdc was in situ obtained by iodination of ligand H3pdc. Complexes 1-4 are pyrazole-bridged heterometallic dinuclear complexes, and 2-4 are isostructural. Complexes 5-8 are isostructural and comprised of an unusual infinite one-dimensional tape-like chain based on pyrazole-bridged heterometallic dinuclear units. The magnetic properties of compounds 1-4, 7 and 8 have been investigated through the magnetic measurement over the temperature range of 1.8-300 K. 相似文献
956.
A facile synthetic procedure has been used to prepare one five-coordinate and four six-coordinate copper(II) complexes of 4′-chloro-2,2′:6′,2″-terpyridine (tpyCl) ligand with different counterions (, , , , and ) in high yields. They are formulated as [Cu(tpyCl-κ3N,N′,N′′)(SO4-κO)(H2O-κO)] · 2H2O (1), trans-[Cu(tpyCl-κ3N,N′,N″)(NO3-κO)2(H2O-κO)] (2), [Cu(tpyCl-κ3N,N′,N″)2](BF4)2 (3), [Cu(tpyCl-κ3N,N′,N″)2](PF6)2 (4) and [Cu(tpyCl-κ3N,N′,N″)2](ClO4)2 (5) and versatile interactions in supramolecular level including coordinative bonding, O-H?O, O-H?Cl, C-H?F, and C-H?Cl hydrogen bonding, π-π stacking play essential roles in forming different frameworks of 1-5. It is concluded that the difference of coordination abilities of the counterions used and the experimental conditions codominate the resulting complexes with 1:1 or 1:2 ratio of metal and ligand. 相似文献
957.
Two new ruthenium (II) complexes containing coupled di(2-pyridyl) and 1,3-dithiole units, cis-[Ru(Medpydt)2(NCS)2] (2, Medpydt = dimethyl 2-(di(2-pyridyl)methylene)-1,3-dithiole-4,5-dicarboxylate) and cis-[Ru(H2dpydt)2(NCS)2] (3, H2dpydt = 2-(di(2-pyridyl)methylene)-1,3-dithiole-4,5-dicarboxylate), have been synthesized and characterized. The structure of complex 2 has been determined by X-ray crystallography. There exist intermolecular H-bonding interactions between carbomethoxy groups on neighboring pyridine rings giving rise to 2D H-bonded arrays. The metal-to-ligand charge-transfer (MLCT) absorptions were observed around 480 nm. Redox properties of ruthenium complexes have been investigated by cyclic voltammetry. Solar cells involving thin films of anatase TiO2 impregnated with cis-[Ru(H2dpydt)2(NCS)2] were prepared, and the photovoltaic performance was preliminarily investigated. 相似文献
958.
959.
Qian Wang Wen‐Lin Li Pu You Juan Su Ming‐Hua Zhu Dong‐Fu Xie Hai‐Yin Zhu Zhi‐Ying He Jian‐Xiu Li Xiao‐Yan Ding Xin Wang Yi‐Ping Hu 《Journal of cellular biochemistry》2009,106(1):16-24
BMI‐1 (B‐cell‐specific Moloney murine leukemia virus integration site 1), a novel oncogene, has attracted much attention in recent years for its involvement in the initiation of a variety of tumors. Recent evidence showed that BMI‐1 was highly expressed in neoplastic skin lesions. However, whether dysregulated BMI‐1 expression is causal for the transformation of skin cells remains unknown. In this study, we stably expressed BMI‐1 in a human keratinocyte cell line, HaCaT. The expression of wild‐type BMI‐1 induced the malignant transformation of HaCaT cells in vitro. More importantly, we found that expression of BMI‐1 promoted formation of squamous cell carcinomas in vivo. Furthermore, we showed that BMI‐1 expression led to the downregulation of tumore suppressors, such as p16INK4a and p14ARF, cell adhesion molecules, such as E‐Cadherin, and differentiation related factor, such as KRT6. Therefore, our findings demonstrated that dysregulated BMI‐1 could indeed lead to keratinocytes transformation and tumorigenesis, potentially through promoting cell cycle progression and increasing cell mobility. J. Cell. Biochem. 106: 16–24, 2009. © 2008 Wiley‐Liss, Inc. 相似文献
960.
The effects of fresh thalli, culture filtrate, water-soluble extract and dry powder of two species of macroalgae, Ulva pertusa (Chlorophyta) and Gracilaria lemaneiformis (Rhodophyta), on the growth of a bloom-forming microalga, Heterosigma akashiwo, were studied in co-culture under controlled laboratory conditions. Both fresh thalli and culture filtrate of U. pertusa and G. lemaneiformis, particularly in the form of fresh thalli, significantly inhibited microalgal growth; indeed, the microalga was completely
killed during the course of the experiment. A clear concentration-dependent relationship was observed between the initial
concentration of fresh thalli (either U. pertusa or G. lemaneiformis) and its inhibitory effect on H. akashiwo. Simultaneous nutrient assays showed that nitrate and phosphate were almost exhausted in G. lemaneiformis fresh thalli co-culture but remained well above nutrient limitation for microalgal growth in U. pertusa co-culture, in which the microalgal cells were completely killed. However, daily f/2 medium repletion would obviously alleviate
the growth inhibition in G. lemaneiformis co-culture. Since the present study was carried out under controlled conditions, fluctuations in environmental factors (i.e.,
light, temperature, carbon limitation, bacterial presence and pH) were limited during the experiment. We thus concluded that
allelopathy was the most likely explanation for microalgal growth inhibition in U. pertusa co-culture, while the combined roles of allelopathy and nutrient limitation were responsible for growth inhibition in G. lemaneiformis co-culture. Similarly, macroalgal water-soluble extracts and dry powders affected the co-cultured H. akashiwo greatly, with more obvious effects observed in water-soluble extract co-cultures. A dose-dependent relationship was also
observed over the course of the experiment. It can be concluded that macroalgal thalli contain some bioactive compounds. The
results of the present study suggest that U. pertusa and G. lemaneiformis, especially in the form of fresh thalli, effectively inhibit the growth of H. akashiwo and could thus be potential candidates for use in the control and mitigation of H. akashiwo blooms. 相似文献