共查询到20条相似文献,搜索用时 31 毫秒
1.
《Bioorganic & medicinal chemistry letters》2014,24(7):1692-1694
Antitumor effects of a known bis(imino-quinolyl)palladium(II) complex 1 and its newly synthesized platinum(II) analogue 2 were evaluated against human breast (MCF-7) and human colon (HT-29) cancer cell lines. The complexes gave cytotoxicity profiles that were better than the reference drug cisplatin. The highest cytotoxic activities were pronounced in complex 2 across the two examined cancer cell lines. Both compounds represent potential active drugs based on bimetallic complexes. 相似文献
2.
Previous studies revealed that Mn(II) is accumulated in cultured glial cells to concentrations far above those present in whole brain or in culture medium. The data indicated that Mn(II) moves across the plasma membrane into the cytoplasm by facilitated diffusion or counter-ion transport with Ca(II), then into mitochondria by active transport. The fact that 1–10 M Mn(II) ions activate brain glutamine synthetase makes important the regulation of Mn(II) transport in the CNS. Since Cu(II) and Zn(II) caused significant changes in the accumulation of Mn(II) by glia, the mechanisms by which these ions alter the uptake and efflux of Mn(II) ions has been investigated systematically under chemically defined conditions. The kinetics of [54MN]-Mn(II) uptake and efflux were determined and compared under four different sets of conditions: no adducts, Cu(II) or Zn(II) added externally, and with cells preloaded with Cu(II) or Zn(II) in the presence and absence of external added metal ions. Zn(II) ions inhibit the initial velocity of Mn(II) uptake, increase total Mn(II) accumulated, but do not alter the rate or extent Mn(II) efflux. Cu(II) ions increase both the initial velocity and the net Mn(II) accumulated by glia, with little effect on rate or extent of Mn(II) efflux. These results predict that increases in Cu(II) or Zn(II) levels may also increase the steady-state levels of Mn(II) in the cytoplasmic fraction of glial cells, which may in turn alter the activity of Mn(II)-sensitive enzymes in this cell compartment. 相似文献
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4.
Mariana Dennehy Susana H. Tarulli Sandra D. Mandolesi Gustavo A. Echeverría Eduardo E. Castellano 《Inorganica chimica acta》2007,360(10):3169-3181
The title compounds, for short Ag6(tsac)6 (1) and [Cu4(tsac)4(MeCN)2] · 2MeCN (2), were prepared by the reaction of thiosaccharin with Ag(I) or Cu(II) salts in different solvents. The new complexes were characterized by FT-IR, Raman, UV-Vis and NMR spectroscopy. Their crystal and molecular structures were determined by X-ray diffraction methods. The structures were solved from 1621 (1) and 7080 (2) reflections with I > 2σ(I) and refined to agreement R1-factors of 0.0261 (1) and 0.0456 (2). Ag6(tsac)6 molecule derives from the clustering of six Ag(tsac) moieties related to each other through the crystallographic 3-bar (S6) symmetry operations of the space group. This results in a highly regular molecular structure where the silver atoms are at the corners of an octahedral core slightly compressed along one of its three-fold axis [inter-metallic Ag?Ag contacts of 3.1723(4) and 3.1556(4) Å]. The six thiosaccharinate ligands bridge neighboring Ag atoms along the C3-axis through Ag-N bonds [d(Ag-N) = 2.285(2) Å] at one end and bifurcated Ag-S(thione)-Ag bonds [Ag-S distances of 2.4861(7) and 2.5014(8) Å] at the other end. In contrast, the 2 compound is arranged in the lattice as an irregular tetrameric copper complex [Cu4(tsac)4(MeCN)2] where the metals show different environments. Two copper ions are four-fold coordinated to three tsac ions through the N-atom of one tsac [Cu-N distances of 2.112(3) and 2.064(3) Å] and the thione sulfur atom of the other two [Cu-S distances in the range from 2.284(1) to 2.358(1) Å] and to a MeCN solvent molecule [Cu-N distances of 1.983(4) and 2.052(3) Å]. The other two copper ions are in three-fold environment, one trans-coordinated to two tsac ions [Cu-N distances of 1.912(3) and 1.920(3) Å] and to the thione S-atom of a third ligand [d(Cu-S) = 2.531(1) Å], the other one to the thione sulfur atom of three tsac ligands [Cu-S distances in the range from 2.229(1) to 2.334(1) Å]. The clustering renders the metals to short distances from each other, the shorter Cu?Cu distance being 2.6033(7) Å, as to presume the existence of weak inter-metallic interaction within the cluster. 相似文献
5.
Nirmal K. Shee F.A. Oluwafunmilayo Adekunle Michael G.B. Drew 《Inorganica chimica acta》2011,366(1):198-202
Reaction of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) with Cu(ClO4)2·6H2O in methanol in 3:1 M ratio at room temperature yields light green [CuL3](ClO4)2·H2O (1). The X-ray crystal structure of the hemi acetonitrile solvate [CuL3](ClO4)2·0.5CH3CN has been determined which shows Jahn-Teller distortion in the CuN6 core present in the cation [CuL3]2+. Complex 1 gives an axial EPR spectrum in acetonitrile-toluene glass with g|| = 2.262 (A|| = 169 × 10−4 cm−1) and g⊥ = 2.069. The Cu(II/I) potential in 1 in CH2Cl2 at a glassy carbon electrode is 0.32 V versus NHE. This potential does not change with the addition of extra L in the medium implicating generation of a six-coordinate copper(I) species [CuL3]+ in solution. B3LYP/LanL2DZ calculations show that the six Cu-N bond distances in [CuL3]+ are 2.33, 2.25, 2.32, 2.25, 2.28 and 2.25 Å while the ideal Cu(I)-N bond length in a symmetric Cu(I)N6 moiety is estimated as 2.25 Å. Reaction of L with Cu(CH3CN)4ClO4 in dehydrated methanol at room temperature even in 4:1 M proportion yields [CuL2]ClO4 (2). Its 1H NMR spectrum indicates that the metal in [CuL2]+ is tetrahedral. The Cu(II/I) potential in 2 is found to be 0.68 V versus NHE in CH2Cl2 at a glassy carbon electrode. In presence of excess L, 2 yields the cyclic voltammogram of 1. From 1H NMR titration, the free energy of binding of L to [CuL2]+ to produce [CuL3]+ in CD2Cl2 at 298 K is estimated as −11.7 (±0.2) kJ mol−1. 相似文献
6.
An investigation into the feasibility of removing Cu(II) and Cr(IV) from solution with basidiomycete (Gloeophylum sepiarium, Pleurotus sp.)-colonized sawdust was undertaken. Obeche (Triplochyton scleroxylon) sawdust exposed to the basidiomycetes for 1–3 months reduced the concentration of the metals in the solution to 22.0–84.4 mg/l. The supernatant from the centrifuged mixture of a solution of 100 mg metal ions/l and aqueous extract of a 3-month basidiomycete-degraded obeche sawdust contained lower concentration of the metal ions (38.6–75.4 mg/l). Unextracted sawdust of pigmented tropical timbers, African mahogany (Khaya ivorensis), black afara (Terminalia ivorensis) and camwood (Baphia nitida) exposed to the test basidiomycetes, removed Cu and Cr significantly better than the extracted sawdust. It is hypothesised that some products of basidiomycete wood-degradative activities were ligands which immobilized the test metals. 相似文献
7.
本文报道从人血浆脂蛋白Lp(a)中,分离纯化载脂蛋白(a)。收集富含Lp(a)的混合血浆,超离心,获密度1.05g/ml至1.08g/ml的粗制Lp(a),经过Bio-Gel A5m层析后,证明纯化后的Lp(a)仅与apo(a)抗血清反应,经DTT处理过的Lp(a),在琼脂糖电泳中的泳动率由胶β位移到β位,在印迹免疫反应中,对apo(a)的抗血清反应依然显示在前β位,SDS聚丙烯凝胶电脉的迁移率慢 相似文献
8.
Shirato M Tozawa S Maeda D Watanabe M Nakagama H Masutani M 《Biochemical and biophysical research communications》2007,355(2):451-456
Poly(ADP-ribose) is a biopolymer synthesized by poly(ADP-ribose) polymerases. Recent findings suggest the possibility for modulation of cellular functions including cell death and mitosis by poly(ADP-ribose). Derivatization of poly(ADP-ribose) may be useful for investigating the effects of poly(ADP-ribose) on various cellular processes. We prepared poly(etheno ADP-ribose) (poly(epsilonADP-ribose)) by converting the adenine moiety of poly(ADP-ribose) to 1-N(6)-etheno adenine residues. Poly(epsilonADP-ribose) is shown to be highly resistant to digestion by poly(ADP-ribose) glycohydrolase (Parg). On the other hand, poly(epsilonADP-ribose) could be readily digested by phosphodiesterase. Furthermore, poly(epsilonADP-ribose) inhibited Parg activity to hydrolyse ribose-ribose bonds of poly(ADP-ribose). This study suggests the possibility that poly(epsilonADP-ribose) might be a useful tool for studying the poly(ADP-ribose) dynamics and function of Parg. This study also implies that modification of the adenine moiety of poly(ADP-ribose) abrogates the susceptibility to digestion by Parg. 相似文献
9.
Three types of DNA: approximately 2700 bp polydeoxyguanylic olydeoxycytidylic acid [poly(dG)-poly(dC)], approximately 2700 bp polydeoxyadenylic polydeoxythymidylic acid [poly(dA)-poly(dT)] and 2686 bp linear plasmid pUC19 were deposited on a mica surface and imaged by atomic force microscopy. Contour length measurements show that the average length of poly(dG)-poly(dC) is approximately 30% shorter than that of poly(dA)-poly(dT) and the plasmid. This led us to suggest that individual poly(dG)-poly(dC) molecules are immobilized on mica under ambient conditions in a form which is likely related to the A-form of DNA in contrast to poly(dA)-poly(dT) and random sequence DNA which are immobilized in a form that is related to the DNA B-form. 相似文献
10.
The mitogen-activated protein kinase (MAPK) cascade is one of the major and evolutionally conserved signaling pathways and plays a pivotal role in the regulation of stress and developmental signals in plants.Here,we identified one gene,GhMPK6,encoding an MAPK protein in cotton.GFP fluorescence assay demonstrated that GhMAPK6 is a cytoplasm localized protein.Quantitative RT-PCR analysis revealed that mRNA accumulation of GhMPK6 was significantly promoted by abscisic acid (ABA).Overexpression of GhMPK6 gene in the T-DNA insertion mutant atmkkl (SALK_015914) conferred a wild-type phenotype to the transgenic plants in response to ABA.Under ABA treatment,cotyledon greening/expansion in GhMPK6 transgenic lines and wild type was significantly inhibited,whereas the atmkkl mutant showed a relatively high cotyledon greening/expansion ratio.Furthermore,CAT1 expression and H2O2 levels in leaves of GhMPK6 transgenic lines and wild type were remarkably higher than those of atmkkl mutant with ABA treatment.Collectively,our results suggested that GhMPK6 may play an important role in ABA-induced CAT1 expression and H2O2 production. 相似文献
11.
The effect of copper(II), lead(II) and chromium(VI) ions on the growth and bioaccumulation properties of Aspergillus niger was investigated as a function of initial pH and initial metal ion concentration. The optimum pH values for growth and metal ion accumulation were determined as 5.0, 4.5 and 3.5 for copper(II), lead(II) and chromium(VI) ions, respectively. Although all metal ion concentrations caused an inhibition effect on the growth of A. niger, it was capable of removing of copper(II) and lead(II) with a maximum specific uptake capacity of 15.6 and 34.4 mg g−1 at 100 mg dm−3 initial copper(II) and lead(II) concentration, respectively. Growth of A. niger was highly effected by chromium(VI) ions and inhibited by 75 mg dm−3 initial chromium(VI) concentration since some inhibition occurred at lower concentrations. 相似文献
12.
The stability constants of Am+3, Cm3+ and Eu3+ with ortho silicate, were measured at pH 3.50 and in ionic strengths of 0.20-1.00 M (NaClO4) by the solvent extraction method. The Am+3, Cm3+ and Eu3+ forms 1:1 complex with ortho silicate ion at pH 3.60 with the stability constant (log β1) value of 8.02 ± 0.10, 7.78 ± 0.08 and 7.81 ± 0.11, respectively. The stability of these metal ions decrease with increased ionic strength from 0.20 to 1.00 M (NaClO4) for silicic acid concentrations of 0.002-0.020 M. Increasing silicic acid concentration above 0.02 M increased the amount of M3+ extracted into the organic phase, contrary to the trend usually observed for increased ligand concentration in solvent extraction. This reversed trend is likely due to the extraction of cationic species of silicic acid by HDEHP. Aging time (60-300 min) had no effect on the stability constant of these metal ions for 0.002-0.020 M silicic acid at pH 3.50 and I = 0.20 M (NaClO4).The fraction of polymeric silicic acid present in solutions of 0.20-4.50 M NaClO4 solutions at pH 3.0-10.0, T = 0-60 °C and aging time = 5-300 min was measured for determination of the silicomolybdate reaction to ascertain the proper conditions to study metal-silicate complexation. 相似文献
13.
Metal complexes of d-glucose (d-Glc) from large cation containing dibromo-dichloro salts of dipositive metals [NEt4]2[MBr2Cl2] (M = Mn, Co, Ni, Cu and Zn) and the disodium salt of glucose were synthesized from a MeOH:MeCN mixture. The complexes were characterized by UV-vis absorption, circular dichroism, IR and proton magnetic resonance spectroscopies, and by elemental analysis, and were found to be Na[M(d-Glc)(OMe)Cl]. Cyclic voltammetric studies of these complexes, in the acidic to neutral pH range, indicated no dissociation, even in highly acidic conditions.This paper is dedicated to Professor Richard H. Holm (Harvard University) on the occasion of his 60th birthday. 相似文献
14.
在室内(25±1℃,L:D=16:8光周期,RH=40%~60%)条件下,研究了茶足柄瘤蚜茧蜂Lysiphlebus testaceipes(Cresson)对苜蓿蚜Aphis craccivora(Koch)若蚜的寄生功能反应。结果表明:苜蓿蚜的龄期对茶足柄瘤蚜茧蜂的寄生作用有很大影响,用功能反应HollingⅡ模型模拟,其模拟方程为Na=1.118 N/(1+0.0184 N)。通过该方程可明确单头雌成蜂在24 h内最多寄生60.60头苜蓿蚜,其寄生1头苜蓿蚜所需时间为0.396 h。在5个温度梯度下,茶足柄瘤蚜茧蜂对苜蓿蚜的寄生功能反应均符合HollingⅡ模型,但不同温度下的功能反应参数有明显的差异。此外茶足柄瘤蚜茧蜂自身密度对寄生有一定的干扰作用,其干扰作用通过Hassell-Varley模型拟合,方程为a=0.0621P-0.3062,表明茶足柄瘤蚜茧蜂雌蜂的发现域随着自身密度的增加而逐渐变小,寄生蜂雌蜂个体间的相互干扰效应降低了寄生效能。 相似文献
15.
生长激素和生长激素受体的多样性 总被引:8,自引:0,他引:8
生长激素及其受体对动物生长发育起着重要的作用。转录过程选择性剪接和存在多种降解途径可能是GH或GHR产生多样性的原因。随着GH结构形态的改变,其功能也在发生变化。GH基因的多样性对鸡的抗病选择性反应与产蛋性能有相关,GH和GHR基因的多样性会影响奶牛的产奶生产性能。GHR的分子多样性可能导致动物生长发育模式的变异,例如动物的矮小病。 相似文献
16.
乳腺癌转移中的磷脂酰胆碱和溶血磷脂酰胆碱分析 总被引:1,自引:0,他引:1
我们以前曾报道花生四烯酸(arachidonic acid,AA)代谢产物可以促进乳腺癌细胞增殖和迁移。为了进一步寻找维持高转移乳腺癌细胞中AA高水平代谢的内源机制,深入探求AA代谢促进乳腺癌细胞转移的分子机理,我们应用HPLC/ESI/MSn技术检测和分析了乳腺癌MCF-7和高转移乳腺癌LM-MCF-7细胞中溶血磷脂酰胆碱(lysophosphatidylcholines,LysoPCs)和磷脂酰胆碱(phosphatidylcholines,PCs)的成分和含量。我们发现了10种LysoPC的含量在LM-MCF-7细胞中显著高于MCF-7细胞,有6种PC可水解产生AA,它们在LM-MCF-7细胞中的含量显著低于MCF-7细胞,提示这些溶血磷脂含量的升高和磷脂含量的降低可能与乳腺癌转移相关。在LM-MCF-7细胞中,COX-2抑制剂吲哚美辛(indomethacin,Indo)和LOX抑制剂(nordihydroguaiaretic acid,NDGA)共同作用可明显下调cPLA2的活性,应用HPLC-ESI-MSn技术比较cPLA2活性下调前后LM-MCF-7细胞中LysoPC和PC含量的变化,发现其中4种PC可被cPLA2水解产生AA。我们还发现,细胞内LysoPC与PC的比值可以反映cPLA2的活性。通过以上研究我们进一步证实了由cPLA2活性调节的AA释放及代谢对乳腺癌转移具有重要作用。 相似文献
17.
Tina Osswald 《Inorganica chimica acta》2010,363(3):474-480
The synthesis, characterization, and application in asymmetric catalytic cyclopropanation of Rh(III) and Ir(III) complexes containing (Sa,RC,RC)-O,O′-[1,1′-binaphthyl-2,2′-diyl]-N,N′-bis[1-phenyl-ethyl]phosphoramidite (1) are reported. The X-ray structures of the half-sandwich complexes [MCl2(C5Me5)(1,κP)] (M = Rh, 2a; M = Ir, 2b) show that the metal-phosphoramidite bond is significantly shorter in the Ir(III) analog. Chloride abstraction from 2a (with CF3SO3SiMe3 or with CF3SO3Me) and from 2b (with AgSbF6) gives the cationic species [MCl(C5Me5)(1,2-η-1,κP)]+ (M = Rh, 3a; M = Ir, 3b), which display a secondary interaction between the metal and a dangling phenethyl group (NCH(CH3)Ph) of the phosphoramidite ligand, as indicated by NMR spectroscopic studies. Complexes 3a and 3b slowly decompose in solution. In the case of 3b, the binuclear species [Ir2Cl3(C5Me5)2]+ is slowly formed, as indicated by an X-ray study. Preliminary catalytic tests showed that 3a cyclopropanates styrene with moderate yield (35%) and diastereoselectivity (70:30 trans:cis ratio) and with 32% ee (for the trans isomer). 相似文献
18.
The helix-helix transitions which occur in poly(dG-dC) · poly(dG-dC) and in poly (dG-m5dC) · poly(dG-m5dC) are commonly assumed to be changes between the right-handed A- or B-DNA double helices and the left-handed Z-DNA structure.
The mechanisms for such transconformations are highly improbable, especially when they are supposed to be active in long polynucleotide
chains organised in semicrystalline fibres. The present alternative possibility assumes that rather than the Z-DNA it is a
right-handed double helix (S-DNA) which actually takes part in these form transitions. Two molecular models of this S form,
in good agreement with X-ray measurements, are proposed. They present alternating C(2′)-endo and C(3′)-endo sugar puckering like the “alternating B-DNA” put forward some years ago. Dihedral angles, sets of atomic coordinates and
stereo views of the two S-DNA structures are given, together with curves of calculated diffracted intensities. Furthermore,
we question the possibility of obtaining semicrystalline fibres with triple helices of poly(dA) · 2poly(dT) in a way which
renders X-ray diffraction efficient. It is suggested that, up to now, only double helices of poly(dA) · poly(dT) can actually
be observed by fibre X-ray diffraction measurements.
Received: 30 March 1999 / Revised version: 30 June 1999 / Accepted: 30 June 1999 相似文献
19.
灵长类(除猕猴属外)在中国的分布 总被引:2,自引:0,他引:2
本文从动态动物地理学观点对中国灵长类(不包括猕猴)的分布进行了分析,提出:(1)中国灵长类自更新世时的分布呈现向南退缩的总趋势,并随气候的变迁而波动,晚更新世向南退缩最为明显;(2)根据Jablonski等认为,我国特有种金丝猴的不连续分布,是由于青藏高原抬升的影响。作者总结了迄今所知的金丝猴生态地理分化特点,对此假说未提出异议,(3)由于除猕猴以外的我国灵长类生态上与森林环境有密切联系,而森林被破坏直接对灵长类在我国分布区的缩小与岛状断裂影响最大,近期可能绝灭的地点甚多。 相似文献
20.
By the reaction of [Ag3(dppm)3I2]I with (NH4)2WS4 in MeCN/DMF (1:1), a trigonal bipyramid-shaped cluster [Ag3 I (dppm)2 WS4] (1) was isolated [dppm = bis (diphenylphosphino) methane]. By the reaction of (NH4)2WS4 with AgSCN and dppm in MeCN/DMF (1:1) in the presence of 1,10-phenathroline, an insect-shaped cluster [Ag4 (SCN)2 (dppm)4WS4]·H2O (2) was synthesized. Compounds 1 and 2 were characterized by single-crystal X-ray diffraction, luminescence, IR, UV-Vis, 1H and 31P NMR spectroscopy. In 1, and μ3-I are coordinated to three Ag atoms, which are further bridged by two dppm ligands. In 2, Ag1 and Ag4 are coordinated by two P atoms from two dppm ligands, one μ3-S from and one S atom from SCN− while Ag2 and Ag3 are coordinated by one μ2-S atom and one μ3-S atom from , two P atoms from two dppm ligands. 相似文献