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Satish Chandra 《The Journal of cell biology》1962,12(3):503-513
An electron microscope study of mitochondria in hamster liver and kidney cells has revealed that at some points the outer membrane of these organelles is continuous with the inner membrane. Also, at such points the discontinuous components of the membrane pairs have free endings. The outer and the inner membranes of a mitochondrion, therefore, may not be two different and distinct entities, as has been conventionally assumed, but may rather be a part of the same unit. Such a morphological structure would make the intramitochondrial substance accessible to the cytoplasmic substance through the intermembrane channel. This structure would also facilitate the swelling of a mitochondrion either by an unfolding of the cristae, or a sliding of the two membranes, or by both these processes occurring simultaneously. 相似文献
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以地塞米松(DEX)诱导小鼠胸腺细胞凋亡;利用PI和AnneXin V/PI流式细胞术分别检测细胞晚期和早期凋亡;利用JC-1和DiOC_6(3)/PI在细胞水平检测凋亡中线粒体膜电势(△ψm)变化:抽提线粒体,利用JC-1直接染色技术检测现存线粒体△ψm情况。实验结果显示,DEX显著诱导胸腺细胞早期和晚期凋亡,凋亡细胞主要来自G_0/G_1期;细胞水平可见DEX介导与△ψm相关的J-aggregate和DiOC_6(3)可染性降低,同时介导线粒体数量显著降低,6h细胞膜完整性无显著变化:单纯线粒体检测结果显示,多数线粒体维持正常△ψm。提示,DEX介导胸腺细胞凋亡中线粒体数量降低,现存线粒体多保持着正常△ψm以维持凋亡过程细胞能量供给。 相似文献
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光动力过程中线粒体膜电位和细胞存活关系 总被引:1,自引:0,他引:1
以1-anilionaphthalene-8-sulfonate(ANS)作荧光探针,通过其荧光光谱研究了苯硫基酞菁锌PcS)、苯硫基铝酞菁(AIPcS)和烷氧基铝酞菁(AIPc)这三种金属酞菁配合物作为光敏剂的光动力作用对癌细胞线粒体膜表面电位的影响.研究表明,光动力作用后线粒体膜表面电位降低,表面电荷数面密度增加.ZnPcS的影响最大,这与酶联免疫检测光动力作用后对癌细胞的杀伤效果相一致,提示细胞线粒体膜可能是金属酞菁配合物在光动力过程中的作用位点。通过比较细胞线粒体膜表面电位以及表面电荷数面密度与细胞存活之间的关系,阐述了光动力作用的物理学机制.同时,由于线粒体膜电位与细胞凋亡的密切关系,金属酞菁配合物对线粒体膜表面电位的影响提供了一个衡量药物疗效的判据。 相似文献
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The squid giant axon was placed in a shallow narrow trough and current was sent in at two electrodes in opposite sides of the trough and out at a third electrode several centimeters away. The potential difference across the membrane was measured between an inside fine capillary electrode with its tip in the axoplasm between the pair of polarizing electrodes, and an outside capillary electrode with its tip flush with the surface of one polarizing electrode. The initial transient was roughly exponential at the anode make and damped oscillatory at the sub-threshold cathode make with the action potential arising from the first maximum when threshold was reached. The constant change of membrane potential, after the initial transient, was measured as a function of the total polarizing current and from these data the membrane potential is obtained as a function of the membrane current density. The absolute value of the resting membrane resistance approached at low polarizing currents is about 23 ohm cm.2. This low value is considered to be a result of the puncture of the axon. The membrane was found to be an excellent rectifier with a ratio of about one hundred between the high resistance at the anode and the low resistance at the cathode for the current range investigated. On the assumption that the membrane conductance is a measure of its ion permeability, these experiments show an increase of ion permeability under a cathode and a decrease under an anode. 相似文献
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ADENINE NUCLEOTIDE-INDUCED CONTRACTION OF THE INNER MITOCHONDRIAL MEMBRANE : I. General Characterization 总被引:5,自引:1,他引:4
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The inner membranes of isolated bovine heart mitochondria undergo pronounced contraction upon being exposed to exogenous adenosine diphosphate (ADP), adenosine triphosphate (ATP), and certain other high-energy phosphate compounds. Contraction results in decrease of inner membrane expanse which in turn results in decrease of intracristal space and increase of mitochondrial optical density (OD). The magnitude of the OD change appears to be proportional to the degree of contraction Half-maximal contraction can be achieved with ADP or ATP at concentrations as low as about 0 3 µM. Atractyloside at concentrations as low as about 1.2 nmol/mg mitochondrial protein completely inhibits the contraction. It is concluded from these and other observations that inner membrane contraction occurs as a result of adenine nucleotide binding to the carrier involved in the exchange of adenine nucleotides across the inner mitochondrial membrane. 相似文献
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脱落酸对线粒体Na^+—K^+ATPase活性的影响 总被引:3,自引:0,他引:3
在提取大豆(Glycine m ax)黄化子叶的线粒体时,于清洗和悬浮介质中加入ABA,发现40 μm ol/L(±) ABA 对线粒体膜结合Na+ -K+ ATPase 活性及线粒体吸氧速率有明显的促进作用。ABA 可使16℃与27℃培养的大豆子叶线粒体膜结合Na+ -K+ ATPase Arrhenius图的折点温度分别下降6.3℃和5.9℃,并将该酶的底物动力学曲线由正协同曲线转变为非协同曲线。表明ABA 可降低线粒体的膜相变温度 相似文献
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外源胆固醇对水稻根端线粒体膜流动性的影响 总被引:2,自引:0,他引:2
应用荧光探剂 1,6-二苯基-1,3,5-己三烯(DPH)观察外源胆固醇对水稻极端线粒体膜流动性的影响。结果表明,无论外源胆固醇通过水培根系吸收或是直接添加给予水稻根端线粒体,都能使DPH与线粒体结合后的荧光强度减弱,使荧光偏振度和微粘度降低,增加水稻根端线粒体膜流动性。 相似文献
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EXPANSION OF THE INNER MEMBRANE COMPARTMENT AND ITS RELATION TO MITOCHONDRIAL VOLUME AND ION TRANSPORT 总被引:9,自引:7,他引:2
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L. Packer J. M. Wrigglesworth P. A. G. Fortes B. C Pressman 《The Journal of cell biology》1968,39(2):382-391
Glutaraldehyde has been used to fix mitochondria undergoing rapid volume changes associated with energized ion transport under oscillatory state conditions and valinomycin-induced potassium uptake. Fixation was found to prevent structural changes which normally occur during ion accumulation or loss. By correlating packed volume measurements with electron microscopy, it is shown that changes in volume associated with ion movements reflect changes in the inner membrane compartment and that this compartment can be related to the sucrose inaccessible space. The method can therefore be used to accurately determine volume changes that arise from ion translocation. 相似文献
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ADENINE NUCLEOTIDE-INDUCED CONTRACTION OF THE INNER MITOCHONDRIAL MEMBRANE : II. Effect of Bongkrekic Acid 总被引:1,自引:0,他引:1
In bovine heart mitochondria bongkrekic acid at concentrations as low as about 4 nmol/mg protein (a) completely inhibits phosphorylation of exogenous adenosine diphosphate (ADP) and dephosphorylation of exogenous adenosine triphosphate (ATP), (b) completely reverses atractyloside inhibition of inner membrane contraction induced by exogenous adenine nucleotides, and (c) decreases the amount of adenine nucleotide required to elicit maximal exogenous adenine nucleotide-induced inner membrane contraction to a level which appears to correspond closely with the concentration of contractile, exogenous adenine nucleotide binding sites Bongkrekic acid at concentrations greater than 4 nmol/mg protein induces inner membrane contraction which seems to depend on the presence of endogenous ADP and/or ATP. The findings appear to be consistent with the interpretations (a) that the inner mitochondrial membrane contains two types of contractile, adenine nucleotide binding sites, (b) that the two sites differ markedly with regard to adenine nucleotide affinity, (c) that the high affinity site is identical with the adenine nucleotide exchange carrier, (d) that the low affinity site is accessible exclusively to endogenous adenine nucleotides and is largely unoccupied in the absence of bongkrekic acid, and (e) that bongkrekic acid increases the affinity of both sites in proportion to the amount of the antibiotic bound to the inner membrane. 相似文献
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氨基酸对蟾蜍卵母细胞膜电位的影响及其作用机制 总被引:1,自引:0,他引:1
本文采用微电极细胞内记录方法观察了23种氨基酸处理后蟾蜍卵母细胞膜电位的变化。丙氨酸、亮氨酸和赖氨酸可致膜电位去极化和膜K~+通透性降低,而色氨酸可致膜电位超极化和膜K~+通透性增加。其他19个氨基酸未见对膜电位有何作用。丙氨酸、亮氨酸和赖氨酸于引起去极化同时,还使卵母细胞孕酮含量成倍增加和卵母细胞趋于成熟。这些作用可被1mmol/L 丁酰 cAMP(db-cAMP)或 50μmol/L 雌二醇完全阻断。另一方面,色氨酸能阻断孕酮(10μmol/L)所致的去极化,但对 db-cAMP 所致的超极化无作用。本文讨论了氨基酸和甾类激素对卵母细胞成熟的调节作用。 相似文献
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研究了Merocyanine540对亚线粒体能量化过程膜电位变化的荧光响应的“on-off”机制,揭示了其快、慢双相反应的特征,探讨了该荧光响应的影响因素,如膜结合二聚体对膜上单体荧光的猝灭,探针与膜的相对浓度以及激发波长的影响。 相似文献
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呼吸链底物和抑制剂对线粒体内膜流动性的影响 总被引:4,自引:0,他引:4
用DPH和ANS标记大鼠肝线粒体内膜,以稳态荧光偏振法,研究了呼吸链底物和抑制剂对内膜流动性的影响。1.苹果酸+谷氨酸、琥珀酸分别为底物,均能引起内膜流动性增加。2.琥珀酸对含心磷脂的脂质体的膜流动性无影响。3.在鱼藤酮存在的条件下,苹果酸+谷氨酸对内膜流动性的增加作用消失,但琥珀酸的作用仍然存在。有氰化钾时则琥珀酸的作用消失。4.不论外加底物存在与否,鱼藤酮使内膜的流动性下降,而氰化钾则使之增加。抗霉素A亦可使内膜的流动性增加。上述结果表明:线粒体内膜流动性与其功能密切相关。电子沿呼吸链传递使线粒体内膜流动性增加,这种变化可能与呼吸链成分的氧化还原态有关。 相似文献
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运动性疲劳状态下大鼠心肌线粒体内膜变化的研究 总被引:5,自引:0,他引:5
采用递增负荷力竭性运动模型,观察了Sprague-Dawley大鼠急性运动至力竭后心肌线粒体内膜流动性、NADH-CoQ还原酶及ATP酶活性的变化。结果表明,大鼠心肌线粒体内膜荧光偏振值较安静时显著增高(P<0.01),示膜流动性降低。线粒体内膜NADH-CoQ还原酶和肌线粒体内膜功能改变,其膜流动性和呼吸链酶活性变化,可能是运动性疲劳的重要膜分子制之一。 相似文献
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膜脂状态在Mg~2+对线粒体H~+-ATP酶影响中的作用 总被引:2,自引:1,他引:1
对猪心线粒体H-ATP酶体系中膜脂在Mg~(2 )的激活功能中起极重要的作用。通过DPH外源荧光探针和5-NSESR探针测膜脂表层Mg~(2 )作用影响的研究表明Mg~(2 )首先对膜脂作用,增加膜脂的有序性。TU颗粒和复合体的酶、色氨酸残基内源荧光偏振度测定的结果表明Mg~(2 )可进而影响内嵌蛋Fo,最终导致F_1上功能位点的构象和功能的变化。但膜脂的原始状态对Mg~(2 )起作用是重要的。 相似文献