• Title/Summary/Keyword: mitochondria

Search Result 1,648, Processing Time 0.025 seconds

POSSIBLE INVOLVEMENT OF Fe-S CENTERS AS MAJOR ENDOGENOUS PHOTOSENSITIZERS IN HIGH LIGHT-CAUSED LOSS OF MEMBRANE STRUCTURE AND FUNCTION OF MITOCHONDRIA

  • Kim, Chang-Sook;Jung, Jin
    • Journal of Photoscience
    • /
    • 제1권1호
    • /
    • pp.9-14
    • /
    • 1994
  • Exposure of isolated intact mitochondria to near UV to visible light resulted in not only loss of respiration, the most well-documented phenomenon regarding phototoxic effects in the respiring organelles, but also lipid peroxidation of membranes and mitochondrial swelling; these turned out to be O$_2$-dependent and thus prevented by anaerobiosis, enhanced by a partial deuteration of the suspension medium, and suppressed by the presence of a singlet oxygen ($^1O_2$) scavenger. Measurements of the spectral dependence of such detrimental effects of light on mitochondrial structure and function revealed that all the resulting spectra bear a significant resemblance to the action spectrum for photogeneration of $^1O_2$ from mitochondrial membranes, which in turn carries the spectral characteristics of light absorption by mitochondrial Fe-S centers. Futhermore, destructing the Fe-S centers by a mercurial treatment of mitochondria brought about a striking reduction of the light-induced membrane peroxidation and swelling of mitochondria. These results are consistent with the suggestion that the impairment of functional, structural integrity of mitochondria caused by strong irradiation is directly related to the production of $^1O_2$ in mitochondria, photosensitized by the Fe-S centers. This paper also presents kinetic data which indicate that, among various membrane-bound protein systems associated with mitochondrial energy metabolism, the respiratory chain is the primary target for photodamage.

  • PDF

미토콘드리아 크리스테에 존재하는 cytochrome-c-oxidase의 단백질 소단위 분포에 관한 연구 (A Study on the Distribution of Cytochrome-c-oxidase Subunit in the Cristae of Mitochondria)

  • 김수진;이지현;정차권
    • Applied Microscopy
    • /
    • 제24권4호
    • /
    • pp.41-51
    • /
    • 1994
  • The topology of the enzyme has been investigated by biochemical studies including chemical labeling and cross linking. Thirteen subunits(polypeptides) of the cytochrome-c-oxidase have localistic characteristics of existing in the matrix side or cytoplasmic side in the mitochondria. In order to observe the distribution of the enzyme subunit on the mitochondria membrane, immunogold-labeling methods were employed. Antibody was obtained from the serum of immunized rabbit with enzyme subunit antigen which was obtained from cytochrome-c-oxidase of the beef heart muscle mitochondria. Beef heart muscle tissue as a tissue antigen was stained with immunized rabbit IgG and protein A gold complex. Electron microscopy has identified the existance of cytochrome-c-oxidase subunit $Mt_I,\;Mt_{II}\;and\;Mt_{III}$ on the membrane of cristae and outer chamber of mitochondria and the subunit $C_{IV}$ on the membrane of cristae and matrix of mitochondria. Particularly, the subunit $C_{IV}$ was also observed to exist in the sarcoplasm of muscle tissue.

  • PDF

Effects of ATP and ADP on iron uptake in rat heart mitochondria

  • Kim, Mi-Sun;Song, Eun-Sook
    • Animal cells and systems
    • /
    • 제14권4호
    • /
    • pp.245-252
    • /
    • 2010
  • Iron uptake in mitochondria and fractionated mitochondria compartments was studied to understand iron transport in heart mitochondria. The inner membrane is most active in iron uptake. Mitochondrial uptake was dependent on iron concentration and the amount of mitochondria. Iron transport was inversely proportional to pH in the range of 6.0 to 8.0. Iron transport reached a maximum after 30 min of incubation at $37^{\circ}C$. Iron uptake was inhibited by 1 mM ATP and stimulated by 1 mM ADP. The oxidative phosphorylation inhibitor oligomycin inhibited iron uptake, but rotenone and antimycin A did not. The divalent ions $Mg^{2+}$, $Cu^{2+}$, $Mn^{2+}$, and $Zn^{2+}$ suppressed iron uptake at $10\;{\mu}M$ and stimulated it at 1 mM. The divalent ion $Ca^{2+}$ stimulated iron uptake at $10\;{\mu}M$ and suppressed it at 1 mM, competing with iron. The uptake of calcium was stimulated by 10 to $1000\;{\mu}M$ ATP, while iron uptake was stimulated reciprocally by 10 to $1000\;{\mu}M$ ADP, suggesting that these ions have movements similar to those of ATP and ADP.

Role of Annexin A5 on Mitochondria-Dependent Apoptosis Induced by Tetramethoxystilbene in Human Breast Cancer Cells

  • Hong, Mihye;Park, Nahee;Chun, Young-Jin
    • Biomolecules & Therapeutics
    • /
    • 제22권6호
    • /
    • pp.519-524
    • /
    • 2014
  • We have previously shown that 2,4,3',5'-tetramethoxystilbene (TMS), a trans-stilbene analogue, induces apoptosis in human cancer cells. However, the detailed mechanisms of mitochondria-dependent apoptosis induced by TMS are not fully understood. In the present study, the possible roles of annexin A5 in TMS-mediated apoptosis were investigated in MCF7 human breast cancer cells. Quantitative real-time PCR analysis and Western blot analysis showed that the expression of annexin A5 was strongly increased in TMS-treated cells. TMS caused a strong translocation of annexin A5 from cytosol into mitochondria. Confocal laser scanning microscopic analysis clearly showed that TMS induced translocation of annexin A5 into mitochondria. TMS increased the expression and oligomerization of voltage-dependent anion channel (VDAC) 1, which may promote mitochondria-dependent apoptosis through disruption of mitochondrial membrane potential. When cells were treated with TMS, the levels of Bax, and Bak as well as annexin A5 were strongly enhanced. Moreover, we found that the cytosolic release of apoptogenic factors such as cytochrome c, or apoptosis-inducing factor (AIF) in mitochondria was markedly increased. Annexin A5 depletion by siRNA led to decreased proapoptotic factors such as Bax, Bak, and annexin A5. Taken together, our results indicate that annexin A5 may play an important role in TMS-mediated mitochondrial apoptosis through the regulation of proapoptotic proteins and VDAC1 expression.

Mitochondria의 Calcium Uptake에 미치는 Ouabain의 영향 (Effect of Ouabain on the Interaction of Mitochondria with Calcium)

  • 홍사악;박찬웅;김명석;정명희
    • 대한약리학회지
    • /
    • 제8권1호
    • /
    • pp.67-75
    • /
    • 1972
  • Many studies on the mechanism of the inotropic action of cardiac glycosides have shown the possible intimate relationship between the mobilization of intracellular calcium and inotropic effect. Evidence obtained from recent studies suggests that cardiac glycosides may increase the intracellular $Ca^{++}$ concentration through the release of this ion from cellular or intracellular membrane. It seemed imperative to study the effect of ouabain on the interaction between mitochondria and $Ca^{++}$, because mitochondria are known to have a rather powerful $Ca^{++}$ pump mechanism which may have an important role on the regulation of intracellular $Ca^{++}$ concentration. The present investigations was made into the effect of ouabain on $Ca^{++}$ untake of mitochondria in the presence of ATP and its dependence on $K^+$ and $Na^+$ in the medium. The results are summarized as follows: 1. The rate of rise in the turbidity of superprecipitation was solely influenced by ionic strength of the medium, not by the species of ion, i.e. $Na^+$ or $K^+$. The higher ionic strength suppressed and the lower enhanced the rate of superprecipitation respectively. 2. No effect of ouabain was found on the rate of superprecipitation. 3. Mitochondria depressed the rate of superpretipitation, and the depressed rate of superprecipitation by mitochondria was reversed by ouabain, and the degree of this reversal was almost identical in $Na^+$ and $K^+$ medium. 4. $Ca^{++}$ uptake of mitochondria was inhibited by ouabain in the presence of ATP and the degree of inhibition showed the dose-response manner in terms of concentration of ouabain. 5. In the absence of ATP, mitochondria took or the $Ca^{++}$ in initial period but released it later. Such uptake and release of $Ca^{++}$ was not influenced by ouabain. 6. It is suggested that intracellular calcium mobilization by ouabain through the action upon the mitochondria was due to inhibition on ATP-dependent $Ca^{++}$ uptake by this agent, not to the action upon so called binding.

  • PDF

허혈 및 재관류가 흰쥐 및 고양이 심장에 미치는 영향에 관한 형태계측학적 연구 (A Quantitative Ultrastructural Study on the Effects of Ischemia and Reperfusion on the Rat and Cat Hearts)

  • 박영식;엄창섭;서영석
    • Applied Microscopy
    • /
    • 제22권1호
    • /
    • pp.42-54
    • /
    • 1992
  • To understand the structural changes of the myocardial myocytes and endothelial cells in ischemic and reperfused heart, and to elucidate their roles in those conditions, the authors observed cat and rat myocardium ultrastructurally and evaluated them with morphometric techniques. In cat, mild ischemia and moderate degree reperfusion injury was induced by ligation of the anterior interventricular branch of left coronary artery and reperfusion. In rat, severe ischemia and irreversible reperfusion iniury was made using in vitro Langendorff techniques. In normal cat myocytes, the volume densities of cytoplasm, myofibrils, mitochondria, sarcoplasmic reticulum and T tubules were $0.11{\pm}0.013,\;0.51{\pm}0.096,\;0.25{\pm}0.082,\;0.09{\pm}0.008,\;0.02{\pm}0.010$ (Mean${\pm}$S.D.) respectively, and the myofibril/mitochondria ratio was $2.33{\pm}1.379$. The numerical density and average volume of mitochondria were $0.76{\pm}0.210/{\mu}m^3$ and $0.33{\pm}0.057{\mu}m^3$ respectively. In normal cat endothelial cells, the volume densities of cytoplasm, cytoplasmic vesicles, tubular systems (including endoplasmic reticulum and Golgi apparatus) and mitochondria were $0.43{\pm}0.023,\;0.28{\pm}0.007,\;0.22{\pm}0.021,\;0.03{\pm}0.014$ respectively. The mean thickness of endothelial cells was $230{\pm}45.2{\mu}m$. The numerical density and average volume of cytoplasmic vesicles were $508{\pm}55.0/{\mu}m^3,\;578{\pm}104.8nm^3$ respectively. In cat myocytes which received mild ischemic injury, the volume densities of organelles were not changed significantly in ischemic and reperfusion states. In reperfusion group myocytes, the numerical density of mitochondria was decreased significantly and the average volume was increased significantly. In endothelial cells, the volume density of tubular system in ischemic group and the average volume of cytoplasmic vesicles in reperfusion group were increased significantly. In rat myocytes which received severe ischemic injury, the volume density and average volume of mitochondria were increased significantly, and the volume density of sarcoplasmic reticulum and numerical density of mitochondria were decreased significantly in both ischemic and reperfusion groups. In ischemic and reperfused endothelial cells, the volume density and numerical density of cytoplasmic vesicles, the volume density of cytoplasm were decreased significantly. The volume densities of tubular system were increased significantly in both ischemic and reperfused groups. The volume density of mitochondria in ischemic group and the average volume of cytoplasmic vesicles in reperfusion group showed significant increase. The authors, based on the above observations, conclude that the mitochondria of myocytes and the cytoplasmic vesicles of endothelia are the first group of targets in ischemic and reperfusion injury and in this respect, the degree of ischemic insult is not significant. The role of myocyte mitochondria in reperfusion injury may be insignificant, but endothelial cells may contribute actively to reperfusion injury.

  • PDF

Mitochondrially Targeted Bcl-2 and Bcl-XL Chimeras Elicit Different Apoptotic Responses

  • Liu, Sen;Pereira, Natasha Ann;Teo, Joong Jiat;Miller, Peter;Shah, Priya;Song, Zhiwei
    • Molecules and Cells
    • /
    • 제24권3호
    • /
    • pp.378-387
    • /
    • 2007
  • The Bcl-2 family of proteins interacts at the mitochondria to regulate apoptosis. However, the anti-apoptotic Bcl-2 and $Bcl-X_L$ are not completely localized to the mitochondria. In an attempt to generate Bcl-2 and $Bcl-X_L$ chimeras that are constitutively localized to the mitochondria, we substituted their C-terminal transmembrane tail or both the C-terminal transmembrane tail and the adjacent loop with the equivalent regions from Bak or Bax mutant (BaxS184V) as these regions determine the mitochondrial localization of Bak and Bax. The effects of these substitutions on subcellular localization and their activities were assessed following expression in HeLa and CHO K1 cells. The substitution of the C-terminal tail or the C-terminal tail and the adjacent loop of Bcl-2 with the equivalent regions from Bak or the Bax mutant resulted in its association with the mitochondria. This change in subcellular localization of Bcl-2 chimeras triggered cells to undergo apoptotic-like cell death. The localization of this Bcl-2 chimera to the mitochondria may be associated with the disruption of mitochondrial membrane potential. Unlike Bcl-2, the loop structure adjacent to the C-terminal tail in $Bcl-X_L$ is crucial for its localization. To localize the $Bcl-X_L$ chimeras to the mitochondria, the loop structure next to the C-terminal tail in $Bcl-X_L$ protein must remain intact and cannot be substituted by the loop from Bax or Bak. The chimeric $Bcl-X_L$ with both its C-terminal tail and the loop structure replaced by the equivalent regions of Bak or Bax mutant localized throughout the entire cytosol. The $Bcl-X_L$ chimeras that are targeted to the mitochondria and the wild type $Bcl-X_L$ provided same protection against cell death under several death inducing conditions.

논우렁이[Cipangopaludina chinensis malleata (Reeve)]의 精蟲形成 過程에 관한 電子顯微鏡的 硏究 (Electron Microscopic Study on the Spermiogenesis of Cipangopaludina chinensis malleata (Reeve))

  • Kim, Ju-Hee;Park, Won-Chul
    • 한국동물학회지
    • /
    • 제29권2호
    • /
    • pp.121-140
    • /
    • 1986
  • 논우렁이(Cipangopaludina chinensis malleata (Reeve))의 精蟲形成 過程은 核과 細胞質의 變化로부터 시작한다. 核內의 染色質은 stacking 되기 시작하였으며 細胞質에서는 mitochondria의 모임과 軸絲의 出現이 되었다. 그런後에 細胞質은 突出되기 시작하였고, 核은 突部分으로 移動되었다. 精蟲形成過程中에 全 細胞質에서 나타나는 電子密度가 높은 物質들은 分解되거나 細胞間隙으로 exocytosis 되었다. 특히, mitochondria가 軸絲사이에 存在하며, 차츰 頭部쪽으로 移動되어지기 시작하였다. 그리고 exocytosis後에 電子密度가 높은 物質이 軸絲를 둘러싸기 시작했다. 이들 物質이 release되어 顆粒狀態로 微細小管이나 axonemal doublet 微細小管들을 通해서 각 部位로 移動되어졌다. 이러한 顆粒들은 glycogen을 함유하고 있으며 尾部의 바깥층을 이루고 있었다. 終局에 가서는 凝縮된 核은 螺旋形으로 變化하며 頸部는 cylinderical shape로 되고 中片의 mitochondria가 規則的인 lamellar屬으로 變化하여 완전히 成熟된 精蟲으로 되었다. 그러므로, 이러한 現象은 精蟲形成 過程의 特異한 過程을 나타낸다. 頭部의 染色質의 濃縮, 頭部의 螺旋狀 形態로 變化하는 것과 細胞性 物質이 mitochondria와 微細小管에 의하여 尾部의 각 部分으로 移動과 轉移되는 것이다.

  • PDF

전기자극이 흰쥐의 정상 가자미근 형태에 미치는 영향 (Effects of Electrical Stimulation on Normal Soleus Muscle in Rat)

  • 박래준
    • The Journal of Korean Physical Therapy
    • /
    • 제6권1호
    • /
    • pp.61-74
    • /
    • 1994
  • 전기자극이 흰쥐의 정상근에 어떠한 영향을 미치는지를 알아보기 위하여 좌골신경의 표적근인 가자미근을 이용하여 조직계측학적, 조직화학, 전자현미경적 관찰을 하였다. 정상적으로 활동하는 흰쥐의 골격근을 매일 전기자극한 결과 전기자극군은 자극을 시작한 후 2주까지는 근섬유의 굵기와 무게가 증가하고 그 이후로는 큰 변화가 없었다. 특히 근섬유의 종류별로는 적색섬유(red muscle fiber)의 채적밀도가 증가하였고 백색섬유(white muscle fiber)는 줄어드는 양상을 보였다. 조직화학적 검사 결과 전기자극군은 근섬유가 다소비대(hypertrophy)해지고 내근주막과 외근주막 사이가 좁아져 있었다. 정상근에서는 당원이 근섬유의 뚜렷한 구별없이 양성반응을 보였으나 실험군은 특정 근섬유에만 반응이 나타났었다. 또한 NADH-TR반응 결과 전기자극군은 적색섬유가 유의하게 증가하여 생체계측학적 결과와 일치하였고 미세구조적 관찰 결과 정상근의 적색섬유는 근섬유와 평행으로 mitochondria가 형성되어 있었고 백색섬유에서는 근절부위에서 관찰되었다. 그러나 전기자극군에서는 적색섬유는 근초부위에 mitochondria가 많이 관찰되고 백색섬유도 근절부위에 작은 mitochondria의 수가 증가되는 것을 관찰할 수 있었다.

  • PDF

진핵생물과 원핵생물의 미토콘드리아 관련 보존적 유전자 비교 (Comparison of Mitochondria-related Conserved Genes in Eukaryotes and Prokaryotes)

  • 이동근
    • 생명과학회지
    • /
    • 제24권7호
    • /
    • pp.791-797
    • /
    • 2014
  • 원핵과 진핵생물에 공통 보존적인 OG (Orthologous Group of proteins)를 미토콘드리아 관련 OG와 비관련 OG로 나누어 분석하였다. 62개의 원핵-진핵생물 공통적 COG (Clusters of OG)중 20개가 미토콘드리아 관련 OG였고 이들은 모두 번역관련 OG로 생명현상에서의 단백질의 중요성을 확인할 수 있었다. 세포내 절대기생체인 뇌회백염원충은 비교대상 다른 생물들 모두에 공통적인 미토콘드리아 관련 OG가 전혀 없었다. 뇌회백염원충을 제외한 6개 진핵생물과 원핵생물 63종에 모두 보존적인 미토콘드리아 관련 OG는 17개였다. Phylogenetic tree의 distance 분석을 수행하니 보존적 OG가 원핵생물에서 미토콘드리아 관련 OG와 비관련 OG 등 각각 2개의 그룹으로 나누어 졌고(p<0.001, paired t-test) 진핵생물은 그렇지 않았다(p>0.05, paired t-test). 보존성이 가장 높은 ortholog는 미토콘드리아 관련 OG에서는 COG0048-KOG1750 (ribosomal small subunit S12)이었고, 미토콘드리아 비관련 OG에서는 COG0100-KOG0407 (ribosomal small subunit S11)이었다. 본 연구결과는 진화관계 등의 기초학문적 연구와 치료제 개발 등의 자료가 될 수 있을 것이다.