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通过盆栽试验,采用原子吸收分光光度法和非损伤微测技术,研究了NaHCO3胁迫(300 mmol·L-1)对大洋洲滨藜、四翅滨藜和宁夏枸杞3种灌木离子吸收及运转的影响.结果表明: 随着NaHCO3浓度升高,两种滨藜和宁夏枸杞叶片中Na+含量升高,300 mmol·L-1NaHCO3胁迫下,宁夏枸杞叶肉细胞Na+的外排增加,两种滨藜净Na+外排降低;随着胁迫时间的延长,大洋洲滨藜和宁夏枸杞叶片的K+含量下降,Na+/K+升高,四翅滨藜叶片K+含量升高,Na+/K+降低;随着浓度的升高,宁夏枸杞叶片积累Ca2+减少,Na+/Ca2+高于对照,叶肉细胞Ca2+外排;两种滨藜叶Ca2+含量总体呈升高趋势,叶肉细胞Ca2+表现为内流.在NaHCO3胁迫下,3种灌木通过不同的策略来消除Na+毒害.宁夏枸杞叶片Na+的积累抑制了对Ca2+的吸收;两种滨藜Ca2+的内流促使细胞质中游离Ca2+增加,增加的细胞质\[Ca2+\]cyt防治质膜H+ ATPase去极化,限制K+的外排,从而维持细胞内Na+/K+的平衡,其中四翅滨藜调控Na+/K+平衡的能力较强. 相似文献
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为揭示长苞香蒲(Typha domingensis)对盐生湿地生态系统中Na+和K+的吸收与转运特征,探讨长苞香蒲对盐生湿地的生态修复效果,该研究采用人工模拟盐生湿地的方法,设置CK(对照)、T1(浇灌100 mmol·L-1盐水)、T2(浇灌200 mmol·L-1盐水)及T3(浇灌300 mmol·L-1盐水)4种不同盐浓度的人工湿地生态系统,并分别于5月5日(开始盐胁迫处理,S0)、5月30日(S1)、6月30日(S2)和7月30日(S3)测量其株高和干重、植株地上与地下部分Na+和K+的含量以及底泥和水体中Na+和K+的含量以分析长苞香蒲对盐碱湿地的脱盐作用。结果表明:(1)各处理的长苞香蒲的株高和干重随着处理时间的延长呈增加趋势,但与CK相比,各处理生长量随盐浓度升高出现下降趋势。(2)高浓度盐处理(T3)使长苞香蒲的地上部分和地下部分的Na+分别增加了2.5... 相似文献
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Ca2+泵(Ca2+-ATPase)是调节细胞内Ca2+浓度的重要蛋白质之一. Ca2+泵在转运Ca2+的过程中经历一系列构象变化. 其中,E1状态为外向的Ca2+高亲和状态,E2状态则为内向的Ca2+低亲和状态. 目前,骨骼肌内质网Ca2+泵转运Ca2+过程中的几个中间状态,包括E1-2Ca2+,E1-ATP,E1-P-ADP,E2-Pi和E2状态的三维晶体结构已经解析. 介绍这几种状态的晶体结构,并分析Ca2+泵在执行功能过程中结构与功能的关系. 相似文献
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[目的] 为探究重金属对淡水绿藻生长的影响。[方法] 选取对水质检测具有明显指示作用的普通小球藻(Chlorella vulgaris)为实验材料,CdCl2·2H2O和CrCl3·7H2O提供重金属离子,探究不同浓度Cr3+和Cd2+在单一和复合胁迫下对藻细胞浓度、叶绿素a及相关抗氧化酶活性的影响。[结果] 随着Cr3+和Cd2+浓度不断增加,藻细胞浓度呈先增长后下降趋势;叶绿素a含量呈现先下降后升高再下降的现象,浓度为1 mg/L的单一和复合胁迫下有最大值,且毒性作用表现为Cr3+ < Cd2+ < Cr3++Cd2+;与藻细胞膜相关的丙二醛(MDA)和过氧化氢(H2O2)含量随着重金属离子浓度的增大而增长;重金属离子浓度低于10 mg/L时对藻细胞内抗氧化酶系统中的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)表现为促进作用,而大于10 mg/L时具有抑制作用。[结论] 结果表明在单一或复合重金属胁迫下,普通小球藻会充分调动与抗逆性相关的酶来维持自身的正常生长。 相似文献
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川楝素是我国学者从驱蛔中药中分离、鉴定的一个三萜化合物,已证明具选择地影响神经递质释放,有效地对抗肉毒中毒,促进细胞分化、凋亡,抑制肿瘤增殖,抑制昆虫发育和取食,影响K+、Ca2+通道活动等多种生物效应. 综述了证明川楝素抑制多种K+通道,选择地易化L型Ca2+通道和进而升高胞内Ca+浓度的研究资料,并对川楝素产生这些生物效应的机制进行了讨论. 相似文献
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本文用微电极细胞内电位记录、通道阻断剂和放射性同位素等技术发现,锌离子可诱发爆发波放电(BD),钠通道阻断剂——河豚毒素对BD无效应,而钙通道阻断剂——Ca2+则可使BD消失,Cd2+可使[65Zn2+]i量减少。以上结果说明,Zn2+诱发BD的产生机理很可能是Zn2+代替Ca2+通过钙通道进入胞内引起的。 相似文献
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为了探讨重金属Cd2+和Cu2+胁迫对泥蚶消化酶活性的影响,运用酶学分析的方法,按《渔业水质标准》(GB 11607)规定的Cd2+、Cu2+最高限量值的1、2、5、10倍设置重金属离子Cd2+、Cu2+浓度及其组合,研究了在重金属Cd2+、Cu2+胁迫下,30d内泥蚶3种消化酶活性的变化规律。结果表明:与空白对照组相比,在重金属Cd2+、Cu2+或其组合的胁迫下,较低浓度组泥蚶的淀粉酶活性实验前期增强(即被诱导),实验后期减弱(即被抑制),较高浓度组泥蚶的淀粉酶活性从实验一开始就减弱,并保持在较低水平,毒性比较,同一重金属高浓度 > 低浓度,不同重金属及其组合Cu2+ > (Cd2++Cu2+)组合 > Cd2+;泥蚶脂肪酶的活性实验前期增强,实验后期转为微减弱或减弱,毒性比较,同一重金属高浓度 > 低浓度,不同重金属及其组合(Cd2++Cu2+)组合 > Cu2+ > Cd2+;泥蚶胃蛋白酶的活性实验前期增强,且活性呈现升高-降低-再升高-再降低的变化,实验后期分别表现微增强、微减弱和减弱,毒性比较,同一重金属高浓度 > 低浓度,不同重金属及其组合(Cd2++Cu2+)组合 > Cu2+ > Cd2+。可见:环境中的Cd2+和Cu2+对泥蚶的消化酶活性起着明显的影响作用。 相似文献
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用单细胞阳离子测定系统研究了SeO2-3对巨噬细胞内游离Ca2+和Mg2+的影响.实验结果表明:SeO2-3高于10-4mol/L时,有显著的细胞毒性.SeO2-3对细胞的毒性作用使细胞内游离Ca2+和Mg2+的浓度升高但Ca2+浓度的升高速率比Mg2+快.还有,高于10-4mol/L的SeO2-3对红细胞膜上的Ca2+-ATP酶活性有明显抑制作用. 相似文献
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以胭脂草(Rivina humilis)为材料,采用溶液培养法,研究系列浓度的锰铁复合胁迫对其若干逆境生理指标的影响。结果表明,当锰铁复合胁迫浓度为6 mmol/L Mn2++0.5 mmol/L Fe2+时,叶绿素含量和可溶性糖含量均极显著高于对照,并达最大值;与此同时,MDA含量极显著降低,并达呈最小值。该组合处理能维持胭脂草较高水平的保护酶(SOD、POD、CAT)活性。由此说明,适宜浓度的锰铁复合处理,能在一定程度上缓解单一金属的毒害作用,提高胭脂草对锰铁复合胁迫环境的耐受性。 相似文献
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Two new zincophosphites [C6H14N2]0.5[Zn(H2PO3)2] 1 and [C4H12N2]0.5[(CH3)2NH2][Zn2(HPO3)3] 2 have been solvothermally synthesized in mixed solvents of N,N-dimethylformamide (DMF) and 1,4-dioxane (DOA), respectively. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a neutral inorganic chain formed by ZnO4 and HPO2(OH) units. Interestingly, the left- and right-handed hydrogen-bonded helical chains are alternately formed via the hydrogen-bonds between two adjacent chains. Compound 2 exhibits a layer structure with 4- and 12-MRs formed by ZnO4 and HPO3 units, in which two kinds of organic amine molecules both act as countercations to compensate the overall negative electrostatic charge of the anionic network. 相似文献
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The title compounds were made by reacting bis(diphenylphosphino)methane (dppm) with reduced solutions of OsCl64? and Ru2OCl104?. The crystal and molecular structures of these compounds have been determined form three-dimensional X-ray study. The cis-isomers crystallize with one CHCl3 per molecule of the complex. All three compounds crystallize in the monoclinic space group P21/n with unit cell dimensions as follows: Cis-OsCl2(dppm)2·CHCl3: a = 13.415(4) Å, b = 22.859(4) Å, c = 16.693(3) Å, β = 105.77(3)°, V = 4926(3) Å3, Z = 4. cis-RuCl2(dppm)2·CHCl3: a = 13.442(3) Å, b = 22.833(7) Å, c = 16.750(4) Å, β = 105.53(2)°, V = 4953(3) Å3, Z = 4. trans-RuCl2(dppm)2: a = 11.368(7) Å, b = 10.656(6) Å, c = 18.832(12) Å; β = 103.90(6)°, V = 2213(7) Å3; Z = 2. The structures were refined to R = 0.044 (Rw = 0.055) for cis-OsCl2(dppm)2·CHCl3; R = 0.065 (Rw = 0.079) for cis-RuCl2(dppm)2·CHCl3 and R = 0.028 (Rw = 0.038) for trans-RuCl2(dppm)2. The complexes are six coordinate with stable four-membered chelate rings. The PMP angle in the chelate rings is ca. 71° in each case. 相似文献
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Take-aki Koizumi 《Inorganica chimica acta》2008,361(7):2131-2138
The molecular structure of an o-phenylenediamine unit-containing oligophenylene (1), Ph-Ph′-Ph′(2,3-NH2)-Ph′-Ph (Ph = phenyl; Ph′ = p-phenylene; Ph′(2,3-NH2) = 2,3-diamino-p-phenylene), was determined by X-ray crystallography. 1 has a twisted structure, and forms an intermolecular C-H?π interaction network. The -NH2 group of 1 was air-oxidized to an imine, NH, group in the presence of [RuCl2(bpy)2] (bpy = 2,2′-bipyridyl) and gave a ruthenium(II)-benzoquinone diimine complex [Ru(2)(bpy)2](PF6)2 (2: Ph-Ph′-Ph′(2,3-imine)-Ph′-Ph). The molecular structure of [Ru(2)(bpy)2](PF6)2 was confirmed by X-ray crystallography. [Ru(2)(bpy)2](PF6)2 underwent two-step electrochemical reduction with E1/2 = −0.889 V and −1.531 V versus Fc+/Fc. The E1/2’s were located at higher potentials by 91 mV and 117 mV, respectively, than those of reported [Ru(bqdi)(bpy)2](PF6)2 (bqdi = benzoquinone diimine). Electrochemical oxidation of [Ru(2)(bpy)2](PF6)2 occurred at a lower potential by 180 mV than that of [Ru(bqdi)(bpy)2](PF6)2. Occurrence of the easier reduction and oxidation of [Ru(2)(bpy)2](PF6)2 than those of [Ru(bqdi)(bpy)2](PF6)2 is ascribed to the presence of a large π-conjugation system in 2. 相似文献
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Following on from our recent enforced geometry optimization (EGO) investigation of isomerization in cis-stilbene (J Comput Chem, in press) we report the discovery of two interesting new, symmetrical “fused sandwich” isomers of both cis-stilbene and the related cis-azobenzene. The isomers were obtained by applying external forces to pairs of carbon atoms from each of the benzene rings
in cis-stilbene and cis-azobenzene simultaneously, and are all at least 100 kcal mol-1 higher in energy than the starting material. Each new structure was characterized as a minimum by vibrational analysis. Despite
their high energy, all of the new isomers appear to be kinetically stable with respect to rearrangement back to cis-stilbene or cis-azobenzene, respectively. 相似文献
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Vito Di Noto Roberto Zannetti Silvano Bresadola Antonio Marigo Carla Marega 《Inorganica chimica acta》1991,190(2)
The reaction of α-MgCl2 with boiling ethyl acetate affords MgCI2(CH3COOC2H5)2·
(CH3COOC2H5), which is obtained as crystals suitable for X-ray analysis only from the mother liquor. M=315.5, orthorhombic, space group P21221 (No. 18), a=25.077(3), b=8.616(1), c=7.345(1) Å, V=1587.0(3) Å3, Z=4, Dx=1.32 g cm−3,λ A(Mo Kα)=0.71069 Å, μ=4.17 cm−1, F(000)=664, T=298 K, observed reflections: 1667, R=0.059 and Rw=0.069. The structure is composed of polymeric chains of MgCl2(CH3COOC2H5)2 and the ethyl acetate molecules occupy a mutually trans position. 相似文献
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Pavel A. Abramov Rita Hernandez-Molina Alexander V. Virovets Pedro Gili Vladimir P. Fedin 《Inorganica chimica acta》2010,363(13):3330-3337
Reaction of [Mo2O2(μ-S)2(H2O)6]2+ with Mo(CO)6 or metallic Mo under hydrothermal conditions (140 °C, 4 M HCl) gives oxido-sulfido cluster aqua complex [Mo3(μ3-S)(μ-O)2(μ-S)(H2O)9]4+ (1). Similarly, [W3(μ3-S)(μ-O)2(μ-S)(H2O)9]4+ (2) is obtained from [W2O2(μ-S)2(H2O)6]2+ and W(CO)6. While reaction of [Mo2O2(μ-S)2(H2O)6]2+ with W(CO)6 mainly proceeds as simple reduction to give 1, [W2O2(μ-S)2(H2O)6]2+ with Mo(CO)6 produces new mixed-metal cluster [W2Mo(μ3-S)(μ-O)2(μ-S)(H2O)9]4+ (3) as main product. From solutions of 1 in HCl supramolecular adduct with cucurbit[6]uril (CB[6]) {[Mo3O2S2(H2O)6Cl3]2CB[6]}Cl2⋅18H2O (4) was isolated and structurally characterized. The aqua complexes were converted into acetylacetonates [M3O2S2(acac)3(py)3]PF6 (M3 = Mo3, W3, W2Mo; 5a-c), which were characterized by X-ray single crystal analysis, electrospray ionization mass spectrometry and 1H NMR spectroscopy. Crystal structure of (H5O2)(Me4N)4[W3(μ3-S)(μ2-S)(μ2-O)2(NCS)9] (6), obtained from 2, is also reported. 相似文献
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Several niobium and tantalum compounds were prepared that contain either the diamidoamine ligand, [(3,4,5-F3C6H2NCH2CH2)2NMe]2− ([F3N2NMe]2−), or the triamidoamine ligand, [(3,5-Cl2C6H3NCH2CH2)3N]3− ([Cl2N2NMe]3−). The former include [F3N2NMe]TaCl3, [F3N2NMe]NbCl3, [F3N2NMe]TaMe3, [F3N2NMe]NbMe3, [(F3N2NMe)TaMe2][MeB(C6F5)3], [F3N2NMe]Ta(CHSiMe3)(CH2SiMe3), [F3N2NMe]Ta(CH2-t-Bu)Cl2, [F3N2NMe]Ta(CH-t-Bu)(CH3), and [F3N2NMe]Ta(η2-C2H4)(CH2CH3). The latter include [Cl2N2NMe]TaCl2, [Cl2N2NMe]TaMe2, [Cl2N2NMe]Ta(η2-C2H4), and [Cl2N2NMe]Ta(η2-C2H2).X-ray diffraction studies were carried out on [F3N2NMe]Ta(CHSiMe3)(CH2SiMe3), [F3N2NMe]Ta(η2-C2H4)(CH2CH3), and [Cl2N2NMe]TaMe2.. 相似文献
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