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Sample records for isolated mitochondrial outer

  1. Mitochondrial dysfunction underlying outer retinal diseases

    DEFF Research Database (Denmark)

    Lefevere, Evy; Toft-Kehler, Anne Katrine; Vohra, Rupali

    2017-01-01

    Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer...

  2. Destabilization of the Outer and Inner Mitochondrial Membranes by Core and Linker Histones

    Science.gov (United States)

    Cascone, Annunziata; Bruelle, Celine; Lindholm, Dan; Bernardi, Paolo; Eriksson, Ove

    2012-01-01

    Background Extensive DNA damage leads to apoptosis. Histones play a central role in DNA damage sensing and may mediate signals of genotoxic damage to cytosolic effectors including mitochondria. Methodology/Principal Findings We have investigated the effects of histones on mitochondrial function and membrane integrity. We demonstrate that both linker histone H1 and core histones H2A, H2B, H3, and H4 bind strongly to isolated mitochondria. All histones caused a rapid and massive release of the pro-apoptotic intermembrane space proteins cytochrome c and Smac/Diablo, indicating that they permeabilize the outer mitochondrial membrane. In addition, linker histone H1, but not core histones, permeabilized the inner membrane with a collapse of the membrane potential, release of pyridine nucleotides, and mitochondrial fragmentation. Conclusions We conclude that histones destabilize the mitochondrial membranes, a mechanism that may convey genotoxic signals to mitochondria and promote apoptosis following DNA damage. PMID:22523586

  3. Localization of MRP-1 to the outer mitochondrial membrane by the chaperone protein HSP90β.

    Science.gov (United States)

    Roundhill, Elizabeth; Turnbull, Doug; Burchill, Susan

    2016-05-01

    Overexpression of plasma membrane multidrug resistance-associated protein 1 (MRP-1) in Ewing's sarcoma (ES) predicts poor outcome. MRP-1 is also expressed in mitochondria, and we have examined the submitochondrial localization of MRP-1 and investigated the mechanism of MRP-1 transport and role of this organelle in the response to doxorubicin. The mitochondrial localization of MRP-1 was examined in ES cell lines by differential centrifugation and membrane solubilization by digitonin. Whether MRP-1 is chaperoned by heat shock proteins (HSPs) was investigated by immunoprecipitation, immunofluorescence microscopy, and HSP knockout using small hairpin RNA and inhibitors (apoptozole, 17-AAG, and NVPAUY). The effect of disrupting mitochondrial MRP-1-dependent efflux activity on the cytotoxic effect of doxorubicin was investigated by counting viable cell number. Mitochondrial MRP-1 is glycosylated and localized to the outer mitochondrial membrane, where it is coexpressed with HSP90. MRP-1 binds to both HSP90 and HSP70, although only inhibition of HSP90β decreases expression of MRP-1 in the mitochondria. Disruption of mitochondrial MRP-1-dependent efflux significantly increases the cytotoxic effect of doxorubicin (combination index, MRP-1 is expressed in the outer mitochondrial membrane and is a client protein of HSP90β, where it may play a role in the doxorubicin-induced resistance of ES.-Roundhill, E., Turnbull, D., Burchill, S. Localization of MRP-1 to the outer mitochondrial membrane by the chaperone protein HSP90β. © FASEB.

  4. The mitochondrial outer membrane protein MDI promotes local protein synthesis and mtDNA replication.

    Science.gov (United States)

    Zhang, Yi; Chen, Yong; Gucek, Marjan; Xu, Hong

    2016-05-17

    Early embryonic development features rapid nuclear DNA replication cycles, but lacks mtDNA replication. To meet the high-energy demands of embryogenesis, mature oocytes are furnished with vast amounts of mitochondria and mtDNA However, the cellular machinery driving massive mtDNA replication in ovaries remains unknown. Here, we describe a Drosophila AKAP protein, MDI that recruits a translation stimulator, La-related protein (Larp), to the mitochondrial outer membrane in ovaries. The MDI-Larp complex promotes the synthesis of a subset of nuclear-encoded mitochondrial proteins by cytosolic ribosomes on the mitochondrial surface. MDI-Larp's targets include mtDNA replication factors, mitochondrial ribosomal proteins, and electron-transport chain subunits. Lack of MDI abolishes mtDNA replication in ovaries, which leads to mtDNA deficiency in mature eggs. Targeting Larp to the mitochondrial outer membrane independently of MDI restores local protein synthesis and rescues the phenotypes of mdi mutant flies. Our work suggests that a selective translational boost by the MDI-Larp complex on the outer mitochondrial membrane might be essential for mtDNA replication and mitochondrial biogenesis during oogenesis. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  5. From Isolated to Networked: A Paradigmatic Shift in Mitochondrial Physiology

    OpenAIRE

    Aon, Miguel A.

    2010-01-01

    A new paradigm of mitochondrial function in networks is emerging which includes, without undermining, the glorious and still useful paradigm of the isolated mitochondrion. The mitochondrial network paradigm introduces new concepts, tools, and analytical techniques. Among them is that mitochondrial function in networks exhibits interdependence and multiplicative effects based on synchronization mechanisms, which involve communication between mitochondrial neighbors. The collective dynamics of ...

  6. Outer Mitochondrial Membrane Localization of Apoptosis-Inducing Factor: Mechanistic Implications for Release

    Directory of Open Access Journals (Sweden)

    Seong-Woon Yu

    2009-10-01

    Full Text Available Poly(ADP-ribose polymerase-1-dependent cell death (known as parthanatos plays a pivotal role in many clinically important events including ischaemia/reperfusion injury and glutamate excitotoxicity. A recent study by us has shown that uncleaved AIF (apoptosis-inducing factor, but not calpain-hydrolysed truncated-AIF, was rapidly released from the mitochondria during parthanatos, implicating a second pool of AIF that might be present in brain mitochondria contributing to the rapid release. In the present study, a novel AIF pool is revealed in brain mitochondria by multiple biochemical analyses. Approx. 30% of AIF loosely associates with the outer mitochondrial membrane on the cytosolic side, in addition to its main localization in the mitochondrial intermembrane space attached to the inner membrane. Immunogold electron microscopic analysis of mouse brain further supports AIF association with the outer, as well as the inner, mitochondrial membrane in vivo. In line with these observations, approx. 20% of uncleaved AIF rapidly translocates to the nucleus and functionally causes neuronal death upon NMDA (N-methyl-d-aspartate treatment. In the present study we show for the first time a second pool of AIF in brain mitochondria and demonstrate that this pool does not require cleavage and that it contributes to the rapid release of AIF. Moreover, these results suggest that this outer mitochondrial pool of AIF is sufficient to cause cell death during parthanatos. Interfering with the release of this outer mitochondrial pool of AIF during cell injury paradigms that use parthanatos hold particular promise for novel therapies to treat neurological disorders.

  7. The novel 2Fe–2S outer mitochondrial protein mitoNEET displays conformational flexibility in its N-terminal cytoplasmic tethering domain

    International Nuclear Information System (INIS)

    Conlan, Andrea R.; Paddock, Mark L.; Axelrod, Herbert L.; Cohen, Aina E.; Abresch, Edward C.; Wiley, Sandra; Roy, Melinda; Nechushtai, Rachel; Jennings, Patricia A.

    2009-01-01

    The crystal structure of the anti-diabetic drug target mitoNEET obtained from a GFP fusion construct (1.4 Å resolution, R factor = 20.2%) shows that the CDGSH 2Fe–2S binding domains are superimposable with previously determined non-fused constructs. However, there is considerable flexibility in the position of the outer mitochondrial tethering arms resulting in two different conformations in the crystal structure. A primary role for mitochondrial dysfunction is indicated in the pathogenesis of insulin resistance. A widely used drug for the treatment of type 2 diabetes is pioglitazone, a member of the thiazolidinedione class of molecules. MitoNEET, a 2Fe–2S outer mitochondrial membrane protein, binds pioglitazone [Colca et al. (2004 ▶), Am. J. Physiol. Endocrinol. Metab.286, E252–E260]. The soluble domain of the human mitoNEET protein has been expressed C-terminal to the superfolder green fluorescent protein and the mitoNEET protein has been isolated. Comparison of the crystal structure of mitoNEET isolated from cleavage of the fusion protein (1.4 Å resolution, R factor = 20.2%) with other solved structures shows that the CDGSH domains are superimposable, indicating proper assembly of mitoNEET. Furthermore, there is considerable flexibility in the position of the cytoplasmic tethering arms, resulting in two different conformations in the crystal structure. This flexibility affords multiple orientations on the outer mitochondrial membrane

  8. The voltage-dependent anion selective channel 1 (VDAC1 topography in the mitochondrial outer membrane as detected in intact cell.

    Directory of Open Access Journals (Sweden)

    Marianna F Tomasello

    Full Text Available Voltage-Dependent Anion selective Channel maintains the permeability of the outer mitochondrial membrane and is relevant in bioenergetic metabolism and apoptosis. The structure of the protein was shown to be a β-barrel formed by 19 strands. The topology or sideness of the pore has been predicted with various approaches but a general consensus was never reached. This is an important issue since VDAC is considered receptor of Hexokinase and Bcl-2. We fused at VDAC1 C-terminus two tags separated by a caspase cleavage site. Activation in cellulo of caspases was used to eventually separate the two reporters. This experiment did not require the isolation of mitochondria and limited the possibility of outer membrane rupture due to similar procedures. Our results show that the C-terminus end of VDAC faces the mitochondrial inter-membrane space.

  9. Metabolic remodeling precedes mitochondrial outer membrane permeabilization in human glioma xenograft cells.

    Science.gov (United States)

    Ponnala, Shivani; Chetty, Chandramu; Veeravalli, Krishna Kumar; Dinh, Dzung H; Klopfenstein, Jeffrey D; Rao, Jasti S

    2012-02-01

    Glioma cancer cells adapt to changing microenvironment and shift from mitochondrial oxidative phosphorylation to aerobic glycolysis for their metabolic needs irrespective of oxygen availability. In the present study, we show that silencing MMP-9 in combination with uPAR/cathepsin B switch the glycolytic metabolism of glioma cells to oxidative phosphorylation (OXPHOS) and generate reactive oxygen species (ROS) to predispose glioma cells to mitochondrial outer membrane permeabilization. shRNA for MMP-9 and uPAR (pMU) as well as shRNA for MMP-9 and cathepsin B (pMC) activated complexes of mitochondria involved in OXPHOS and inhibited glycolytic hexokinase expression. The decreased interaction of hexokinase 2 with mitochondria in the treated cells indicated the inhibition of glycolysis activation. Overexpression of Akt reversed the pMU- and pMC-mediated OXPHOS to glycolysis switch. The OXPHOS un-coupler oligomycin A altered the expression levels of the Bcl-2 family of proteins; treatment with pMU or pMC reversed this effect and induced mitochondrial outer membrane permeabilization. In addition, our results show changes in mitochondrial pore transition to release cytochrome c due to changes in the VDAC-Bcl-XL and BAX-BAK interaction with pMU and pMC treatments. Taken together, our results suggest that pMU and pMC treatments switch glioma cells from the glycolytic to the OXPHOS pathway through an inhibitory effect on Akt, ROS induction and an increase of cytosolic cytochrome c accumulation. These results demonstrate the potential of pMU and pMC as therapeutic candidates for the treatment of glioma.

  10. Eukaryote-wide sequence analysis of mitochondrial β-barrel outer membrane proteins

    Directory of Open Access Journals (Sweden)

    Fujita Naoya

    2011-01-01

    Full Text Available Abstract Background The outer membranes of mitochondria are thought to be homologous to the outer membranes of Gram negative bacteria, which contain 100's of distinct families of β-barrel membrane proteins (BOMPs often forming channels for transport of nutrients or drugs. However, only four families of mitochondrial BOMPs (MBOMPs have been confirmed to date. Although estimates as high as 100 have been made in the past, the number of yet undiscovered MBOMPs is an open question. Fortunately, the recent discovery of a membrane integration signal (the β-signal for MBOMPs gave us an opportunity to look for undiscovered MBOMPs. Results We present the results of a comprehensive survey of eukaryotic protein sequences intended to identify new MBOMPs. Our search employs recent results on β-signals as well as structural information and a novel BOMP predictor trained on both bacterial and mitochondrial BOMPs. Our principal finding is circumstantial evidence suggesting that few MBOMPs remain to be discovered, if one assumes that, like known MBOMPs, novel MBOMPs will be monomeric and β-signal dependent. In addition to this, our analysis of MBOMP homologs reveals some exceptions to the current model of the β-signal, but confirms its consistent presence in the C-terminal region of MBOMP proteins. We also report a β-signal independent search for MBOMPs against the yeast and Arabidopsis proteomes. We find no good candidates MBOMPs in yeast but the Arabidopsis results are less conclusive. Conclusions Our results suggest there are no remaining MBOMPs left to discover in yeast; and if one assumes all MBOMPs are β-signal dependent, few MBOMP families remain undiscovered in any sequenced organism.

  11. Peripheral-type benzodiazepine receptor: a protein of mitochondrial outer membranes utilizing porphyrins as endogenous ligands

    International Nuclear Information System (INIS)

    Snyder, S.H.; Verma, A.; Trifiletti, R.R.

    1987-01-01

    The peripheral-type benzodiazepine receptor is a site identified by its nanomolar affinity for [ 3 H]diazepam, similar to the affinity of diazepam for the central-type benzodiazepine receptor in the brain. The peripheral type benzodiazepine receptor occurs in many peripheral tissues but has discrete localizations as indicated by autoradiographic studies showing uniquely high densities of the receptors in the adrenal cortex and in Leydig cells of the testes. Subcellular localization studies reveal a selective association of the receptors with the outer membrane of mitochondria. Photoaffinity labeling of the mitochondrial receptor with [ 3 H]flunitrazepam reveals two discrete labeled protein bands of 30 and 35 kDa, respectively. The 35-kDa band appears to be identical with the voltage-dependent anion channel protein porin. Fractionation of numerous peripheral tissues reveals a single principal endogenous ligand for the receptor, consisting of porphyrins, which display nanomolar affinity. Interactions of porphyrins with the mitochondrial receptor may clarify its physiological role and account for many pharmacological actions of benzodiazepines

  12. The pro-apoptotic BH3-only protein Bim interacts with components of the translocase of the outer mitochondrial membrane (TOM).

    Science.gov (United States)

    Frank, Daniel O; Dengjel, Jörn; Wilfling, Florian; Kozjak-Pavlovic, Vera; Häcker, Georg; Weber, Arnim

    2015-01-01

    The pro-apoptotic Bcl-2-family protein Bim belongs to the BH3-only proteins known as initiators of apoptosis. Recent data show that Bim is constitutively inserted in the outer mitochondrial membrane via a C-terminal transmembrane anchor from where it can activate the effector of cytochrome c-release, Bax. To identify regulators of Bim-activity, we conducted a search for proteins interacting with Bim at mitochondria. We found an interaction of Bim with Tom70, Tom20 and more weakly with Tom40, all components of the Translocase of the Outer Membrane (TOM). In vitro import assays performed on tryptically digested yeast mitochondria showed reduced Bim insertion into the outer mitochondrial membrane (OMM) indicating that protein receptors may be involved in the import process. However, RNAi against components of TOM (Tom40, Tom70, Tom22 or Tom20) by siRNA, individually or in combination, did not consistently change the amount of Bim on HeLa mitochondria, either at steady state or upon de novo-induction. In support of this, the individual or combined knock-downs of TOM receptors also failed to alter the susceptibility of HeLa cells to Bim-induced apoptosis. In isolated yeast mitochondria, lack of Tom70 or the TOM-components Tom20 or Tom22 alone did not affect the import of Bim into the outer mitochondrial membrane. In yeast, expression of Bim can sensitize the cells to Bax-dependent killing. This sensitization was unaffected by the absence of Tom70 or by an experimental reduction in Tom40. Although thus the physiological role of the Bim-TOM-interaction remains unclear, TOM complex components do not seem to be essential for Bim insertion into the OMM. Nevertheless, this association should be noted and considered when the regulation of Bim in other cells and situations is investigated.

  13. The pro-apoptotic BH3-only protein Bim interacts with components of the translocase of the outer mitochondrial membrane (TOM.

    Directory of Open Access Journals (Sweden)

    Daniel O Frank

    Full Text Available The pro-apoptotic Bcl-2-family protein Bim belongs to the BH3-only proteins known as initiators of apoptosis. Recent data show that Bim is constitutively inserted in the outer mitochondrial membrane via a C-terminal transmembrane anchor from where it can activate the effector of cytochrome c-release, Bax. To identify regulators of Bim-activity, we conducted a search for proteins interacting with Bim at mitochondria. We found an interaction of Bim with Tom70, Tom20 and more weakly with Tom40, all components of the Translocase of the Outer Membrane (TOM. In vitro import assays performed on tryptically digested yeast mitochondria showed reduced Bim insertion into the outer mitochondrial membrane (OMM indicating that protein receptors may be involved in the import process. However, RNAi against components of TOM (Tom40, Tom70, Tom22 or Tom20 by siRNA, individually or in combination, did not consistently change the amount of Bim on HeLa mitochondria, either at steady state or upon de novo-induction. In support of this, the individual or combined knock-downs of TOM receptors also failed to alter the susceptibility of HeLa cells to Bim-induced apoptosis. In isolated yeast mitochondria, lack of Tom70 or the TOM-components Tom20 or Tom22 alone did not affect the import of Bim into the outer mitochondrial membrane. In yeast, expression of Bim can sensitize the cells to Bax-dependent killing. This sensitization was unaffected by the absence of Tom70 or by an experimental reduction in Tom40. Although thus the physiological role of the Bim-TOM-interaction remains unclear, TOM complex components do not seem to be essential for Bim insertion into the OMM. Nevertheless, this association should be noted and considered when the regulation of Bim in other cells and situations is investigated.

  14. Frequency response for electromotility of isolated outer hair cells of the guinea pig

    NARCIS (Netherlands)

    Wit, HP; vanDijk, P; Segenhout, HM

    1996-01-01

    Frequency and impulse responses were determined for isolated guinea pig outer hair cells by electrically stimulating the cells between two wire electrodes with white noise. Cells were attached to the bottom of a small culture dish at one end while the other end was freely moving. Results have the

  15. Clearing the outer mitochondrial membrane from harmful proteins via lipid droplets

    Czech Academy of Sciences Publication Activity Database

    Bischof, J.; Salzmann, M.; Streubel, M.K.; Hašek, Jiří; Geltinger, F.; Duschl, J.; Bresgen, N.; Briza, P.; Hašková, Danuša; Lejsková, Renata; Sopjani, M.; Richter, K.; Rinnerthaler, M.

    2017-01-01

    Roč. 3, March 20 (2017), č. článku 17016. E-ISSN 2058-7716 R&D Projects: GA ČR(CZ) GA16-05497S; GA MŠk(CZ) 7AMB16AT006 Institutional support: RVO:61388971 Keywords : mitochondrial membrane * harmful protein s * lipid droplets Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology

  16. Mitochondrial expression and activity of P-glycoprotein under oxidative stress in outer blood-retinal barrier

    Directory of Open Access Journals (Sweden)

    Yue-Hong Zhang

    2017-07-01

    Full Text Available AIM: To investigate the role of oxidative stress in regulating the functional expression of P-glycoprotein (P-gp in mitochondria of D407 cells. METHODS: D407 cells were exposed to different ranges of concentrations of H2O2. The mitochondrial location of P-gp in the cells subjected to oxidative stress was detected by confocal analysis. Expression of P-gp in isolated mitochondria was assessed by Western blot. The pump activity of P-gp was evaluated by performing the efflux study on isolated mitochondria with Rhodamine 123 (Rho-123 alone and in the presence of P-gp inhibitor (Tariquidar using flow cytometry analysis. The cells were pretreated with 10 mmol/L N-acetylcysteine (NAC for 30min before exposing to H2O2, and analyzed the mitochondrial extracts by Western blot and flow cytometry. RESULTS: P-gp was co-localized in the mitochondria by confocal laser scanning microscopy, and it was also detected in the mitochondria of D407 cells using Western blot. Exposure to increasing concentrations of H2O2 led to gradually increased expression and location of P-gp in the mitochondria of cells. Rho-123 efflux assay showed higher uptake of Rho-123 on isolated mitochondria in the presence of Tariquidar both in normal and oxidative stress state. H2O2 up-regulated P-gp in D407 cells, which could be reversed by NAC treatment. CONCLUSION: H2O2 could up-regulate the functional expression of P-gp in mitochondria of D407 cells, while antioxidants might suppress oxidative-stress-induced over-expression of functional P-gp. It is indicative that limiting the mitochondrial P-gp transport in retinal pigment epithelium cells would be to improve the effect of mitochondria-targeted antioxidant therapy in age-related macular degeneration-like retinopathy.

  17. Low altitude observations of the energetic electrons in the outer radiation belt during isolated substorms

    International Nuclear Information System (INIS)

    Varga, L.; Venkatesan, D.; Johns Hopkins Univ., Laurel, MD; Meng, C.I.

    1985-01-01

    The low energy (1-20 keV) detector registering particles onboard the polar-orbiting low altitude (approx. 850 km) DMSP-F2 and -F3 satellites also records high energy electrons penetrating the detector walls. Thus the dynamics of this electron population at L=3.5 can be studied during isolated periods of magnetospheric substorms identified by the indices of auroral electrojet (AE), geomagnetic (Ksub(p)) and ring current (Dsub(st)). Temporal changes in the electron flux during the substorms are observed to be an additional contribution riding over the top of the pre-storm (or geomagnetically quiet-time) electron population; the duration of the interval of intensity variations is observed to be about the same as that of the enhancement of the AE index. This indicates the temporal response of the outer radiation belt to the substorm activity, since the observation was made in the ''horns'' of the outer radiation belt. The observed enhanced radiation at low altitude may associate with the instantaneous increase and/or dumping of the outer radiation belt energetic electrons during each isolated substorm activity. (author)

  18. Protective effect of taurine on the light-induced disruption of isolated frog rod outer segments

    International Nuclear Information System (INIS)

    Pasantes-Morales, H.; Ademe, R.M.; Quesada, O.

    1981-01-01

    Isolated frog rod outer segments (ROS) incubated in a Krebs-bicarbonate medium, and illuminated for 2 h, show a profound alteration in their structure. This is characterized by distention of discs, vesiculation, and a marked swelling. The light-induced ROS disruption requires the presence of bicarbonate and sodium chloride. Replacement of bicarbonate by TRIS or HEPES protects ROS structure. Also, substitution of sodium chloride by sucrose or choline chloride maintains unaltered the ROS structure. Deletion of calcium, magnesium, or phosphate does not modify the effect produced by illumination. An increased accumulation of labeled bicarbonate and tritiated water is observed in illuminated ROS, as compared with controls in the dark. The presence of taurine, GABA, or glycine, at concentrations of 5-25 mM, effectively counteracts the light-induced ROS disruption. Taurine (25 mM) reduces labeled bicarbonate and tritiated water levels to those observed in the dark incubated ROS

  19. Ca2+ and Mg2+-enhanced reduction of arsenazo III to its anion free radical metabolite and generation of superoxide anion by an outer mitochondrial membrane azoreductase.

    Science.gov (United States)

    Moreno, S N; Mason, R P; Docampo, R

    1984-12-10

    At the concentrations usually employed as a Ca2+ indicator, arsenazo III underwent a one-electron reduction by rat liver mitochondria to produce an azo anion radical as demonstrated by electron-spin resonance spectroscopy. Either NADH or NADPH could serve as a source of reducing equivalents for the production of this free radical by intact rat liver mitochondria. Under aerobic conditions, addition of arsenazo III to rat liver mitochondria produced an increase in electron flow from NAD(P)H to molecular oxygen, generating superoxide anion. NAD(P)H generated from endogenous mitochondrial NAD(P)+ by intramitochondrial reactions could not be used for the NAD(P)H azoreductase reaction unless the mitochondria were solubilized by detergent or anaerobiosis. In addition, NAD(P)H azoreductase activity was higher in the crude outer mitochondrial membrane fraction than in mitoplasts and intact mitochondria. The steady-state concentration of the azo anion radical and the arsenazo III-stimulated cyanide-insensitive oxygen consumption were enhanced by calcium and magnesium, suggesting that, in addition to an enhanced azo anion radical-stabilization by complexation with the metal ions, enhanced reduction of arsenazo III also occurred. Accordingly, addition of cations to crude outer mitochondrial membrane preparations increased arsenazo III-stimulated cyanide-insensitive O2 consumption, H2O2 formation, and NAD(P)H oxidation. Antipyrylazo III was much less effective than arsenazo III in increasing superoxide anion formation by rat liver mitochondria and gave a much weaker electron spin resonance spectrum of an azo anion radical. These results provide direct evidence of an azoreductase activity associated with the outer mitochondrial membrane and of a stimulation of arsenazo III reduction by cations.

  20. Stabilization of mitochondrial membrane potential prevents doxorubicin-induced cardiotoxicity in isolated rat heart

    International Nuclear Information System (INIS)

    Montaigne, David; Marechal, Xavier; Baccouch, Riadh; Modine, Thomas; Preau, Sebastien; Zannis, Konstantinos; Marchetti, Philippe; Lancel, Steve; Neviere, Remi

    2010-01-01

    The present study was undertaken to examine the effects of doxorubicin on left ventricular function and cellular energy state in intact isolated hearts, and, to test whether inhibition of mitochondrial membrane potential dissipation would prevent doxorubicin-induced mitochondrial and myocardial dysfunction. Myocardial contractile performance and mitochondrial respiration were evaluated by left ventricular tension and its first derivatives and cardiac fiber respirometry, respectively. NADH levels, mitochondrial membrane potential and glucose uptake were monitored non-invasively via epicardial imaging of the left ventricular wall of Langendorff-perfused rat hearts. Heart performance was reduced in a time-dependent manner in isolated rat hearts perfused with Krebs-Henseleit solution containing 1 μM doxorubicin. Compared with controls, doxorubicin induced acute myocardial dysfunction (dF/dt max of 105 ± 8 mN/s in control hearts vs. 49 ± 7 mN/s in doxorubicin-treated hearts; *p < 0.05). In cardiac fibers prepared from perfused hearts, doxorubicin induced depression of mitochondrial respiration (respiratory control ratio of 4.0 ± 0.2 in control hearts vs. 2.2 ± 0.2 in doxorubicin-treated hearts; *p < 0.05) and cytochrome c oxidase kinetic activity (24 ± 1 μM cytochrome c/min/mg in control hearts vs. 14 ± 3 μM cytochrome c/min/mg in doxorubicin-treated hearts; *p < 0.05). Acute cardiotoxicity induced by doxorubicin was accompanied by NADH redox state, mitochondrial membrane potential, and glucose uptake reduction. Inhibition of mitochondrial permeability transition pore opening by cyclosporine A largely prevented mitochondrial membrane potential dissipation, cardiac energy state and dysfunction. These results suggest that in intact hearts an impairment of mitochondrial metabolism is involved in the development of doxorubicin cardiotoxicity.

  1. Isolation of suberin from birch outer bark and cork using ionic liquids: A new source of macromonomers

    OpenAIRE

    Ferreira, Rui; Garcia, Helga; Sousa, Andreia F.; Freire, Carmen S. R.; Silvestre, Armando J. D.; Rebelo, Luis Paulo N.; Pereira, Cristina Silva

    2013-01-01

    Cholinium hexanoate, a biocompatible and biodegradable ionic liquid, was recently demonstrated to efficiently and selectively extract suberin domains from cork, combining high extraction efficiency with isolation of a partial depolymerised material. In the present paper, we report a comparative study of the characterisation of suberin extracted from birch outer bark and from cork using cholinium hexanoate. It became apparent that both extracted suberin samples showed still a cross-linked natu...

  2. A proteomic screen reveals the mitochondrial outer membrane protein Mdm34p as an essential target of the F-box protein Mdm30p.

    Science.gov (United States)

    Ota, Kazuhisa; Kito, Keiji; Okada, Satoshi; Ito, Takashi

    2008-10-01

    Ubiquitination plays various critical roles in eukaryotic cellular regulation and is mediated by a cascade of enzymes including ubiquitin protein ligase (E3). The Skp1-Cullin-F-box protein complex comprises the largest E3 family, in each member of which a unique F-box protein binds its targets to define substrate specificity. Although genome sequencing uncovers a growing number of F-box proteins, most of them have remained as "orphans" because of the difficulties in identification of their substrates. To address this issue, we tested a quantitative proteomic approach by combining the stable isotope labeling by amino acids in cell culture (SILAC), parallel affinity purification (PAP) that we had developed for efficient enrichment of ubiquitinated proteins, and mass spectrometry (MS). We applied this SILAC-PAP-MS approach to compare ubiquitinated proteins between yeast cells with and without over-expressed Mdm30p, an F-box protein implicated in mitochondrial morphology. Consequently, we identified the mitochondrial outer membrane protein Mdm34p as a target of Mdm30p. Furthermore, we found that mitochondrial defects induced by deletion of MDM30 are not only recapitulated by a mutant Mdm34p defective in interaction with Mdm30p but alleviated by ubiquitination-mimicking forms of Mdm34p. These results indicate that Mdm34p is a physiologically important target of Mdm30p.

  3. Tissue specific phosphorylation of mitochondrial proteins isolated from rat liver, heart muscle, and skeletal muscle

    DEFF Research Database (Denmark)

    Bak, Steffen; León, Ileana R; Jensen, Ole Nørregaard

    2013-01-01

    -specific phosphorylation sites were identified in tissue-specific enzymes such as those encoded by HMGCS2, BDH1, PCK2, CPS1, and OTC in liver mitochondria, and CKMT2 and CPT1B in heart and skeletal muscle. Kinase prediction showed an important role for PKA and PKC in all tissues but also for proline-directed kinases......Phosphorylation of mitochondrial proteins in a variety of biological processes is increasingly being recognized and may contribute to the differences in function and energy demands observed in mitochondria from different tissues such as liver, heart, and skeletal muscle. Here, we used a combination...... of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC-MS/MS on isolated mitochondria to investigate the tissue-specific mitochondrial phosphoproteomes of rat liver, heart, and skeletal muscle. In total, we identified 899 phosphorylation sites in 354 different mitochondrial proteins including...

  4. Bax-mediated mitochondrial outer membrane permeabilization (MOMP), distinct from the mitochondrial permeability transition, is a key mechanism in diclofenac-induced hepatocyte injury: Multiple protective roles of cyclosporin A.

    Science.gov (United States)

    Siu, Woen Ping; Pun, Pamela Boon Li; Latchoumycandane, Calivarathan; Boelsterli, Urs A

    2008-03-15

    Diclofenac, a widely used nonsteroidal anti-inflammatory drug, has been associated with rare but severe cases of clinical hepatotoxicity. Diclofenac causes concentration-dependent cell death in human hepatocytes (after 24-48 h) by mitochondrial permeabilization via poorly defined mechanisms. To explore whether the cyclophilin D (CyD)-dependent mitochondrial permeability transition (mPT) and/or the mitochondrial outer membrane permeabilization (MOMP) was primarily involved in mediating cell death, we exposed immortalized human hepatocytes (HC-04) to apoptogenic concentrations of diclofenac (>500 microM) in the presence or absence of inhibitors of upstream mediators. The CyD inhibitor, cyclosporin A (CsA, 2 microM) fully inhibited diclofenac-induced cell injury, suggesting that mPT was involved. However, CyD gene silencing using siRNA left the cells susceptible to diclofenac toxicity, and CsA still protected the CyD-negative cells from lethal injury. Diclofenac induced early (9 h) activation of Bax and Bak and caused mitochondrial translocation of Bax, indicating that MOMP was involved in cell death. Inhibition of Bax protein expression by using siRNA significantly protected HC-04 from diclofenac-induced cell injury. Diclofenac also induced early Bid activation (tBid formation, 6 h), which is an upstream mechanism that initiates Bax activation and mitochondrial translocation. Bid activation was sensitive to the Ca2+ chelator, BAPTA. In conclusion, we found that Bax/Bak-mediated MOMP is a key mechanism of diclofenac-induced lethal cell injury in human hepatocytes, and that CsA can prevent MOMP through inhibition of Bax activation. These data support our concept that the Ca2+-Bid-Bax-MOMP axis is a critical pathway in diclofenac (metabolite)-induced hepatocyte injury.

  5. Bax-mediated mitochondrial outer membrane permeabilization (MOMP), distinct from the mitochondrial permeability transition, is a key mechanism in diclofenac-induced hepatocyte injury: Multiple protective roles of cyclosporin A

    International Nuclear Information System (INIS)

    Siu, W.P.; Pun, Pamela Boon Li; Latchoumycandane, Calivarathan; Boelsterli, Urs A.

    2008-01-01

    Diclofenac, a widely used nonsteroidal anti-inflammatory drug, has been associated with rare but severe cases of clinical hepatotoxicity. Diclofenac causes concentration-dependent cell death in human hepatocytes (after 24-48 h) by mitochondrial permeabilization via poorly defined mechanisms. To explore whether the cyclophilin D (CyD)-dependent mitochondrial permeability transition (mPT) and/or the mitochondrial outer membrane permeabilization (MOMP) was primarily involved in mediating cell death, we exposed immortalized human hepatocytes (HC-04) to apoptogenic concentrations of diclofenac (> 500 μM) in the presence or absence of inhibitors of upstream mediators. The CyD inhibitor, cyclosporin A (CsA, 2 μM) fully inhibited diclofenac-induced cell injury, suggesting that mPT was involved. However, CyD gene silencing using siRNA left the cells susceptible to diclofenac toxicity, and CsA still protected the CyD-negative cells from lethal injury. Diclofenac induced early (9 h) activation of Bax and Bak and caused mitochondrial translocation of Bax, indicating that MOMP was involved in cell death. Inhibition of Bax protein expression by using siRNA significantly protected HC-04 from diclofenac-induced cell injury. Diclofenac also induced early Bid activation (tBid formation, 6 h), which is an upstream mechanism that initiates Bax activation and mitochondrial translocation. Bid activation was sensitive to the Ca 2+ chelator, BAPTA. In conclusion, we found that Bax/Bak-mediated MOMP is a key mechanism of diclofenac-induced lethal cell injury in human hepatocytes, and that CsA can prevent MOMP through inhibition of Bax activation. These data support our concept that the Ca 2+ -Bid-Bax-MOMP axis is a critical pathway in diclofenac (metabolite)-induced hepatocyte injury

  6. Mitochondrial function in type I cells isolated from rabbit arterial chemoreceptors.

    Science.gov (United States)

    Duchen, M R; Biscoe, T J

    1992-05-01

    1. In this, and the accompanying paper (Duchen & Biscoe, 1992), we test the hypothesis that the oxygen sensitivity of mitochondrial electron transport forms a basis for transduction in the carotid body, the primary peripheral arterial oxygen sensor. We here describe for isolated type I cells the changes in autofluorescence of mitochondrial NAD(P)H that accompany changes in PO2. 2. NAD(P)H autofluorescence (excitation, 340-360 nm; emission peak, 450 nm) increased with anoxia, reflecting a rise in the NAD(P)H/NAD(P) ratio. Graded increases in autofluorescence were seen in response to graded decreases in PO2, suggesting that mitochondrial function is progressively altered below a PO2 of about 60 mmHg. 3. A mitochondrial origin for the NAD(P)H autofluorescence was suggested by the mutual exclusion of the responses to anoxia and cyanide. 4. Oxidized flavoproteins fluoresce when excited at 450 nm with an emission peak at 550 nm. The small signals obtained under these conditions increased with uncoupler and showed a graded decrease with falling PO2 reflecting a rise in the FADH/FAD ratio. 5. Hypoxia raises [Ca2+]i. The hypoxia-induced changes in mitochondrial function were not secondary to this rise. A brief K(+)-induced depolarization leads to a transient increase in [Ca2+]i. At the same time there is a rapid decrease in NAD(P)H autofluorescence followed by an increase that far outlasts the rise in [Ca2+]i. This delayed increase in autofluorescence was smaller than was the increase with anoxia, even though K(+)-induced depolarization raised [Ca2+]i more than does anoxia. In Ca(2+)-free solutions the depolarization-induced changes were abolished, while those associated with hypoxia were maintained. 6. The changes of autofluorescence with K(+)-induced depolarization appear to reflect (i) oxidation of NAD(P)H by stimulation of respiration following mitochondrial Ca2+ uptake and (ii) reduction of NAD(P) by the Ca(2+)-dependent activation of mitochondrial dehydrogenases. This

  7. Differential Permeabilization Effects of Ca2+ and Valinomycin on the Inner and Outer Mitochondrial Membranes as Revealed by Proteomics Analysis of Proteins Released from Mitochondria*S⃞

    Science.gov (United States)

    Yamada, Akiko; Yamamoto, Takenori; Yamazaki, Naoshi; Yamashita, Kikuji; Kataoka, Masatoshi; Nagata, Toshihiko; Terada, Hiroshi; Shinohara, Yasuo

    2009-01-01

    It is well established that cytochrome c is released from mitochondria when the permeability transition (PT) of this organelle is induced by Ca2+. Our previous study showed that valinomycin also caused the release of cytochrome c from mitochondria but without inducing this PT (Shinohara, Y., Almofti, M. R., Yamamoto, T., Ishida, T., Kita, F., Kanzaki, H., Ohnishi, M., Yamashita, K., Shimizu, S., and Terada, H. (2002) Permeability transition-independent release of mitochondrial cytochrome c induced by valinomycin. Eur. J. Biochem. 269, 5224–5230). These results indicate that cytochrome c may be released from mitochondria with or without the induction of PT. In the present study, we examined the protein species released from valinomycin- and Ca2+-treated mitochondria by LC-MS/MS analysis. As a result, the proteins located in the intermembrane space were found to be specifically released from valinomycin-treated mitochondria, whereas those in the intermembrane space and in the matrix were released from Ca2+-treated mitochondria. These results were confirmed by Western analysis. Furthermore to examine how the protein release occurred, we examined the correlation between the species of released proteins and those of the abundant proteins in mitochondria. Consequently most of the proteins released from mitochondria treated with either agent were highly expressed proteins in mitochondria, indicating that the release occurred not selectively but in a manner dependent on the concentration of the proteins. Based on these results, the permeabilization effects of Ca2+ and valinomycin on the inner and outer mitochondrial membranes are discussed. PMID:19218587

  8. Inner Super-Earths, Outer Gas Giants: How Pebble Isolation and Migration Feedback Keep Jupiters Cold

    Science.gov (United States)

    Fung, Jeffrey; Lee, Eve J.

    2018-06-01

    The majority of gas giants (planets of masses ≳102 M ⊕) are found to reside at distances beyond ∼1 au from their host stars. Within 1 au, the planetary population is dominated by super-Earths of 2–20 M ⊕. We show that this dichotomy between inner super-Earths and outer gas giants can be naturally explained should they form in nearly inviscid disks. In laminar disks, a planet can more easily repel disk gas away from its orbit. The feedback torque from the pile-up of gas inside the planet’s orbit slows down and eventually halts migration. A pressure bump outside the planet’s orbit traps pebbles and solids, starving the core. Gas giants are born cold and stay cold: more massive cores are preferentially formed at larger distances, and they barely migrate under disk feedback. We demonstrate this using two-dimensional hydrodynamical simulations of disk–planet interaction lasting up to 105 years: we track planet migration and pebble accretion until both come to an end by disk feedback. Whether cores undergo runaway gas accretion to become gas giants or not is determined by computing one-dimensional gas accretion models. Our simulations show that in an inviscid minimum mass solar nebula, gas giants do not form inside ∼0.5 au, nor can they migrate there while the disk is present. We also explore the dependence on disk mass and find that gas giants form further out in less massive disks.

  9. Mitochondrial outer membrane permeabilization increases reactive oxygen species production and decreases mean sperm velocity but is not associated with DNA fragmentation in human sperm.

    Science.gov (United States)

    Treulen, F; Uribe, P; Boguen, R; Villegas, J V

    2016-02-01

    Does induction of mitochondrial outer membrane permeabilization (MOMP) in vitro affect specific functional parameters of human spermatozoa? Our findings show that MOMP induction increases intracellular reactive oxygen species (ROS) and decreases mean sperm velocity but does not alter DNA integrity. MOMP in somatic cells is related to a variety of apoptotic traits, such as alteration of mitochondrial membrane potential (ΔΨm), and increase in ROS production and DNA fragmentation. Although the presence of these apoptotic features has been reported in spermatozoa, to date the effects of MOMP on sperm function and DNA integrity have not been analysed. The study included spermatozoa from fertile donors. Motile sperm were obtained using the swim-up method. The highly motile sperm were collected and diluted with human tubal fluid to a final cell concentration of 5 × 10(6) ml(-1). To induce MOMP, selected sperm were treated at 37°C for 4 h with a mimetic of a Bcl-2 pro-apoptotic protein, ABT-737. MOMP was evaluated by relocating of cytochrome c. In addition, the effect of ABT-737 on mitochondrial inner membrane permeabilization was assessed using the calcein-AM/cobalt chloride method. In turn, ΔΨm was evaluated with JC-1 staining, intracellular ROS production with dihydroethidium, sperm motility was analysed by computer-assisted sperm analysis and DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. Measurements were performed by flow cytometry. MOMP was associated with ΔΨm dissipation (P < 0.05), increased ROS production (P < 0.05) and decreased mean sperm velocity (P < 0.05), but it was not associated with DNA fragmentation. MOMP did not induce a large increase in ROS, which could explain the negligible effect of MOMP on sperm DNA fragmentation under our experimental conditions. The study was carried out in vitro using highly motile sperm, selected by swim-up, from healthy donors. The results obtained in this

  10. Assessing Mitochondrial Bioenergetics in Isolated Mitochondria from Various Mouse Tissues Using Seahorse XF96 Analyzer.

    Science.gov (United States)

    Iuso, Arcangela; Repp, Birgit; Biagosch, Caroline; Terrile, Caterina; Prokisch, Holger

    2017-01-01

    Working with isolated mitochondria is the gold standard approach to investigate the function of the electron transport chain in tissues, free from the influence of other cellular factors. In this chapter, we outline a detailed protocol to measure the rate of oxygen consumption (OCR) with the high-throughput analyzer Seahorse XF96. More importantly, this protocol wants to provide practical tips for handling many different samples at once, and take a real advantage of using a high-throughput system. As a proof of concept, we have isolated mitochondria from brain, heart, liver, muscle, kidney, and lung of a wild-type mouse, and measured basal respiration (State II), ADP-stimulated respiration (State III), non-ADP-stimulated respiration (State IV o ), and FCCP-stimulated respiration (State III u ) using respiratory substrates specific to the respiratory chain complex I (RCCI) and complex II (RCCII). Mitochondrial purification and Seahorse runs were performed in less than eight working hours.

  11. A protocol for isolating insect mitochondrial genomes: a case study of NUMT in Melipona flavolineata (Hymenoptera: Apidae).

    Science.gov (United States)

    Françoso, Elaine; Gomes, Fernando; Arias, Maria Cristina

    2016-07-01

    Nuclear mitochondrial DNA insertions (NUMTs) are mitochondrial DNA sequences that have been transferred into the nucleus and are recognized by the presence of indels and stop codons. Although NUMTs have been identified in a diverse range of species, their discovery was frequently accidental. Here, our initial goal was to develop and standardize a simple method for isolating NUMTs from the nuclear genome of a single bee. Subsequently, we tested our new protocol by determining whether the indels and stop codons of the cytochrome c oxidase subunit I (COI) sequence of Melipona flavolineata are of nuclear origin. The new protocol successfully demonstrated the presence of a COI NUMT. In addition to NUMT investigations, the protocol described here will also be very useful for studying mitochondrial mutations related to diseases and for sequencing complete mitochondrial genomes with high read coverage by Next-Generation technology.

  12. The mitochondrial outer membrane protein mitoNEET is a redox enzyme catalyzing electron transfer from FMNH2 to oxygen or ubiquinone.

    Science.gov (United States)

    Wang, Yiming; Landry, Aaron P; Ding, Huangen

    2017-06-16

    Increasing evidence suggests that mitoNEET, a target of the type II diabetes drug pioglitazone, is a key regulator of energy metabolism in mitochondria. MitoNEET is anchored to the mitochondrial outer membrane via its N-terminal α helix domain and hosts a redox-active [2Fe-2S] cluster in its C-terminal cytosolic region. The mechanism by which mitoNEET regulates energy metabolism in mitochondria, however, is not fully understood. Previous studies have shown that mitoNEET specifically interacts with the reduced flavin mononucleotide (FMNH 2 ) and that FMNH 2 can quickly reduce the mitoNEET [2Fe-2S] clusters. Here we report that the reduced mitoNEET [2Fe-2S] clusters can be readily oxidized by oxygen. In the presence of FMN, NADH, and flavin reductase, which reduces FMN to FMNH 2 using NADH as the electron donor, mitoNEET mediates oxidation of NADH with a concomitant reduction of oxygen. Ubiquinone-2, an analog of ubiquinone-10, can also oxidize the reduced mitoNEET [2Fe-2S] clusters under anaerobic or aerobic conditions. Compared with oxygen, ubiquinone-2 is more efficient in oxidizing the mitoNEET [2Fe-2S] clusters, suggesting that ubiquinone could be an intrinsic electron acceptor of the reduced mitoNEET [2Fe-2S] clusters in mitochondria. Pioglitazone or its analog NL-1 appears to inhibit the electron transfer activity of mitoNEET by forming a unique complex with mitoNEET and FMNH 2 The results suggest that mitoNEET is a redox enzyme that may promote oxidation of NADH to facilitate enhanced glycolysis in the cytosol and that pioglitazone may regulate energy metabolism in mitochondria by inhibiting the electron transfer activity of mitoNEET. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Isolation and Identification of Outer Membrane Proteins of Helicobacter Pylori of Iranian Patient by SDS-PAGE

    Directory of Open Access Journals (Sweden)

    M. Doosty

    1998-04-01

    Full Text Available The function of Helicobacter pylori (H.pylori is confirmed as one of the factors which motivates gastric and duodenal ulcer and gastritis. Various methods are used to diagnose the infection. Serological tests are the easiest and most harmless for the patients. Probably, H.pylori strains in Iran are different from the strains in other countries. Hence, it seems neccessary to design a specific serological test to recognize and identify different strains of bacterial antigenic proteins of Iranian patients."nSince the most manifest and specific to these bacterial antigens are the "Outer Membrane Protein" (OMP, therefore, the first necessary step is to separate and purify H.pylori OMP and then to identify antigenic proteins."nIn this study, we received bacteria colony that belonged to 15 patients with gastric or duodenal ulcer, which had been growed in blood agar or brucella broth. After processing such as washing, freezing and defreezing, sonicating, centrifugation with high speed (10,000 g and treatment with sarcosyl, the sarcosyl insoluble fraction was extracted. Sodium Dodecyl Sulfate - Poly Acrylamide Gel Electrophoresis (SDS-PAGE was preformed. From all 15 OMP specimens, we isolated protein bands."nThe first two bands with higher MW, were major bands and the two lighter bands were the minor bands. Approximate MW of these 4 proteins are equal to 67000, 61000, 30000 and 17000 dalton

  14. Suberin fatty acids isolated from outer birch bark improve moisture barrier properties of cellulose ether films intended for tablet coatings.

    Science.gov (United States)

    Heinämäki, Jyrki; Halenius, Anna; Paavo, Maaja; Alakurtti, Sami; Pitkänen, Pauliina; Pirttimaa, Minni; Paaver, Urve; Kirsimäe, Kalle; Kogermann, Karin; Yliruusi, Jouko

    2015-07-15

    We showed that the addition of suberin fatty acids (SFAs) even at small concentrations significantly improves the water vapor barrier properties of hydroxypropyl methylcellulose (HPMC) films. SFAs were isolated from the outer birch bark using extractive hydrolysis. The effects of SFAs on the film formation of aqueous HPMC were investigated with free films plasticized with polyethylene glycol (PEG 400). Special attention was paid on the physical solid-state, moisture barrier and mechanical stress-strain properties of films intended for tablet film coatings. Topography and surface morphology, glass transition temperature (Tg), tensile strength, Young's modulus, and water vapor permeation (WVP) of films were studied. The addition of SFAs lowered the Tg of films suggesting partial enhancement in film plasticization. The WVP of films decreased with increasing SFAs concentration up to 15% (calculated as a % w/w from a polymer weight). The WVP value for a non-suberized reference film and suberized film plasticized with PEG 400 was 2.13×10(-6) and 0.69[×10(-6) g/(mm(2)×h)×mm/Pa], respectively. The addition of SFAs impaired the mechanical stress-strain properties of HPMC films by reducing the deformation capacity of film. In conclusion, the film properties and performance of aqueous HPMC can be modified by including SFAs in the films. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Outer Membrane Protein A Conservation among Orientia tsutsugamushi Isolates Suggests Its Potential as a Protective Antigen and Diagnostic Target

    Directory of Open Access Journals (Sweden)

    Sean M. Evans

    2018-06-01

    Full Text Available Scrub typhus threatens one billion people in the Asia-Pacific area and cases have emerged outside this region. It is caused by infection with any of the multitude of strains of the bacterium Orientia tsutsugamushi. A vaccine that affords heterologous protection and a commercially-available molecular diagnostic assay are lacking. Herein, we determined that the nucleotide and translated amino acid sequences of outer membrane protein A (OmpA are highly conserved among 51 O. tsutsugamushi isolates. Molecular modeling revealed the predicted tertiary structure of O. tsutsugamushi OmpA to be very similar to that of the phylogenetically-related pathogen, Anaplasma phagocytophilum, including the location of a helix that contains residues functionally essential for A. phagocytophilum infection. PCR primers were developed that amplified ompA DNA from all O. tsutsugamushi strains, but not from negative control bacteria. Using these primers in quantitative PCR enabled sensitive detection and quantitation of O. tsutsugamushi ompA DNA from organs and blood of mice that had been experimentally infected with the Karp or Gilliam strains. The high degree of OmpA conservation among O. tsutsugamushi strains evidences its potential to serve as a molecular diagnostic target and justifies its consideration as a candidate for developing a broadly-protective scrub typhus vaccine.

  16. Mitochondrial DNA structure of an isolated Tunisian Berber population and its relationship with Mediterranean populations.

    Science.gov (United States)

    Ben Halim, Nizar; Hsouna, Sana; Lasram, Khaled; Chargui, Mariem; Khemira, Laaroussi; Saidane, Rachid; Abdelhak, Sonia; Kefi, Rym

    2018-02-01

    Douiret is an isolated Berber population from South-Eastern Tunisia. The strong geographic and cultural isolation characterising this population might have contributed to remarkable endogamy and consanguinity, which were practiced for several centuries. The objective of this study is to evaluate the mitochondrial DNA (mtDNA) genetic structure of Douiret and to compare it to other Mediterranean populations with a special focus on major haplogroup T. Genomic DNA was extracted from blood samples of 58 unrelated individuals collected from the different patrilineal lineages of the population. The hypervariable region 1 of the mtDNA was amplified and sequenced. For comparative analyses, additional HVS1 sequences (n = 4857) were compiled from previous studies. The maternal background of the studied sample from Douiret was mainly of Eurasian origin (74%) followed by Sub-Saharan (17%) and North African (3%) lineages. Douiret harbours the highest frequency of haplogroup T in the Mediterranean region, assigned to the unique subclade T1a (38%). Phylogenetic analysis showed an outlier position of Douiret at the Mediterranean level. The genetic structure of Douiret highlights the presence of founders, most likely of Near/Middle Eastern origin, who conquered this area during the Middle/Late Upper Palaeolithic and Neolithic dispersals.

  17. Molecular characterization of Taenia multiceps isolates from Gansu Province, China by sequencing of mitochondrial cytochrome C oxidase subunit 1.

    Science.gov (United States)

    Li, Wen Hui; Jia, Wan Zhong; Qu, Zi Gang; Xie, Zhi Zhou; Luo, Jian Xun; Yin, Hong; Sun, Xiao Lin; Blaga, Radu; Fu, Bao Quan

    2013-04-01

    A total of 16 Taenia multiceps isolates collected from naturally infected sheep or goats in Gansu Province, China were characterized by sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The complete cox1 gene was amplified for individual T. multiceps isolates by PCR, ligated to pMD18T vector, and sequenced. Sequence analysis indicated that out of 16 T. multiceps isolates 10 unique cox1 gene sequences of 1,623 bp were obtained with sequence variation of 0.12-0.68%. The results showed that the cox1 gene sequences were highly conserved among the examined T. multiceps isolates. However, they were quite different from those of the other Taenia species. Phylogenetic analysis based on complete cox1 gene sequences revealed that T. multiceps isolates were composed of 3 genotypes and distinguished from the other Taenia species.

  18. Mitochondrial genomic comparison of Clonorchis sinensis from South Korea with other isolates of this species.

    Science.gov (United States)

    Wang, Daxi; Young, Neil D; Koehler, Anson V; Tan, Patrick; Sohn, Woon-Mok; Korhonen, Pasi K; Gasser, Robin B

    2017-07-01

    Clonorchiasis is a neglected tropical disease that affects >35 million people mainly in China, Vietnam, South Korea and some parts of Russia. The disease-causing agent, Clonorchis sinensis, is a liver fluke of humans and other piscivorous animals, and has a complex aquatic life cycle involving snails and fish intermediate hosts. Chronic infection in humans causes liver disease and associated complications including malignant bile duct cancer. Central to control and to understanding the epidemiology of this disease is knowledge of the specific identity of the causative agent as well as genetic variation within and among populations of this parasite. Although most published molecular studies seem to suggest that C. sinensis represents a single species and that genetic variation within the species is limited, karyotypic variation within C. sinensis among China, Korea (2n=56) and Russian Far East (2n=14) suggests that this taxon might contain sibling species. Here, we assessed and applied a deep sequencing-bioinformatic approach to sequence and define a reference mitochondrial (mt) genome for a particular isolate of C. sinensis from Korea (Cs-k2), to confirm its specific identity, and compared this mt genome with homologous data sets available for this species. Comparative analyses revealed consistency in the number and structure of genes as well as in the lengths of protein-coding genes, and limited genetic variation among isolates of C. sinensis. Phylogenetic analyses of amino acid sequences predicted from mt genes showed that representatives of C. sinensis clustered together, with absolute nodal support, to the exclusion of other liver fluke representatives, but sub-structuring within C. sinensis was not well supported. The plan now is to proceed with the sequencing, assembly and annotation of a high quality draft nuclear genome of this defined isolate (Cs-k2) as a basis for a detailed investigation of molecular variation within C. sinensis from disparate

  19. Analysis of outer membrane vesicle associated proteins isolated from the plant pathogenic bacterium Xanthomonas campestris pv. campestris

    Directory of Open Access Journals (Sweden)

    Niehaus Karsten

    2008-06-01

    Full Text Available Abstract Background Outer membrane vesicles (OMVs are released from the outer membrane of many Gram-negative bacteria. These extracellular compartments are known to transport compounds involved in cell-cell signalling as well as virulence associated proteins, e.g. the cytolysine from enterotoxic E. coli. Results We have demonstrated that Xanthomonas campestris pv. campestris (Xcc releases OMVs into the culture supernatant during growth. A proteome study identified 31 different proteins that associate with the OMV fraction of which half are virulence-associated. A comparison with the most abundant outer membrane (OM proteins revealed that some proteins are enriched in the OMV fraction. This may be connected to differences in the LPS composition between the OMVs and the OM. Furthermore, a comparison of the OMV proteomes from two different culture media indicated that the culture conditions have an impact on the protein composition. Interestingly, the proteins that are common to both culture conditions are mainly involved in virulence. Conclusion Outer membrane vesicles released from the OM of Xcc contain membrane- and virulence-associated proteins. Future experiments will prove whether these structures can serve as "vehicles" for the transport of virulence factors into the host membrane.

  20. Oleuropein isolated from Fraxinus rhynchophylla inhibits glutamate-induced neuronal cell death by attenuating mitochondrial dysfunction.

    Science.gov (United States)

    Kim, Mi Hye; Min, Ju-Sik; Lee, Joon Yeop; Chae, Unbin; Yang, Eun-Ju; Song, Kyung-Sik; Lee, Hyun-Shik; Lee, Hong Jun; Lee, Sang-Rae; Lee, Dong-Seok

    2017-04-27

    Glutamate-induced neurotoxicity is related to excessive oxidative stress accumulation and results in the increase of neuronal cell death. In addition, glutamate has been reported to lead to neurodegenerative diseases, including Parkinson's and Alzheimer's diseases.It is well known that Fraxinus rhynchophylla contains a significant level of oleuropein (Ole), which exerts various pharmacological effects. However, the mechanism of neuroprotective effects of Ole is still poorly defined. In this study, we aimed to investigate whether Ole prevents glutamate-induced toxicity in HT-22 hippocampal neuronal cells. The exposure of the glutamate treatment caused neuronal cell death through an alteration of Bax/Bcl-2 expression and translocation of mitochondrial apoptosis-inducing factor (AIF) to the cytoplasm of HT-22 cells. In addition, glutamate induced an increase in dephosphorylation of dynamin-related protein 1 (Drp1), mitochondrial fragmentation, and mitochondrial dysfunction. The pretreatment of Ole decreased Bax expression, increased Bcl-2 expression, and inhibited the translocation of mitochondrial AIF to the cytoplasm. Furthermore, Ole amended a glutamate-induced mitochondrial dynamic imbalance and reduced the number of cells with fragmented mitochondria, regulating the phosphorylation of Drp1 at amino acid residue serine 637. In conclusion, our results show that Ole has a preventive effect against glutamate-induced toxicity in HT-22 hippocampal neuronal cells. Therefore, these data imply that Ole may be an efficient approach for the treatment of neurodegenerative diseases.

  1. Evidence for Amino Acid Snorkeling from a High-Resolution, In Vivo Analysis of Fis1 Tail-Anchor Insertion at the Mitochondrial Outer Membrane.

    Science.gov (United States)

    Keskin, Abdurrahman; Akdoğan, Emel; Dunn, Cory D

    2017-02-01

    Proteins localized to mitochondria by a carboxyl-terminal tail anchor (TA) play roles in apoptosis, mitochondrial dynamics, and mitochondrial protein import. To reveal characteristics of TAs that may be important for mitochondrial targeting, we focused our attention upon the TA of the Saccharomyces cerevisiae Fis1 protein. Specifically, we generated a library of Fis1p TA variants fused to the Gal4 transcription factor, then, using next-generation sequencing, revealed which Fis1p TA mutations inhibited membrane insertion and allowed Gal4p activity in the nucleus. Prompted by our global analysis, we subsequently analyzed the ability of individual Fis1p TA mutants to localize to mitochondria. Our findings suggest that the membrane-associated domain of the Fis1p TA may be bipartite in nature, and we encountered evidence that the positively charged patch at the carboxyl terminus of Fis1p is required for both membrane insertion and organelle specificity. Furthermore, lengthening or shortening of the Fis1p TA by up to three amino acids did not inhibit mitochondrial targeting, arguing against a model in which TA length directs insertion of TAs to distinct organelles. Most importantly, positively charged residues were more acceptable at several positions within the membrane-associated domain of the Fis1p TA than negatively charged residues. These findings, emerging from the first high-resolution analysis of an organelle targeting sequence by deep mutational scanning, provide strong, in vivo evidence that lysine and arginine can "snorkel," or become stably incorporated within a lipid bilayer by placing terminal charges of their side chains at the membrane interface. Copyright © 2017 by the Genetics Society of America.

  2. Dextran strongly increases the Michaelis constants of oxidative phosphorylation and of mitochondrial creatine kinase in heart mitochondria

    NARCIS (Netherlands)

    Gellerich, F.N.; Laterveer, F.D.; Korzeniewski, B.; Zierz, S.; Nicolaij, K.

    1998-01-01

    Macromolecules restore the morphological changes which occur upon isolation of mitochondria in normally used isolation media. It was shown that in the presence of dextrans the permeability of mitochondrial outer membrane for adenine nucleotides decreases which may have considerable implications for

  3. Mitochondrial myopathies.

    Science.gov (United States)

    DiMauro, Salvatore

    2006-11-01

    Our understanding of mitochondrial diseases (defined restrictively as defects of the mitochondrial respiratory chain) is expanding rapidly. In this review, I will give the latest information on disorders affecting predominantly or exclusively skeletal muscle. The most recently described mitochondrial myopathies are due to defects in nuclear DNA, including coenzyme Q10 deficiency and mutations in genes controlling mitochondrial DNA abundance and structure, such as POLG, TK2, and MPV17. Barth syndrome, an X-linked recessive mitochondrial myopathy/cardiopathy, is associated with decreased amount and altered structure of cardiolipin, the main phospholipid of the inner mitochondrial membrane, but a secondary impairment of respiratory chain function is plausible. The role of mutations in protein-coding genes of mitochondrial DNA in causing isolated myopathies has been confirmed. Mutations in tRNA genes of mitochondrial DNA can also cause predominantly myopathic syndromes and--contrary to conventional wisdom--these mutations can be homoplasmic. Defects in the mitochondrial respiratory chain impair energy production and almost invariably involve skeletal muscle, causing exercise intolerance, cramps, recurrent myoglobinuria, or fixed weakness, which often affects extraocular muscles and results in droopy eyelids (ptosis) and progressive external ophthalmoplegia.

  4. Noninvasive diagnostics of mitochondrial disorders in isolated lymphocytes with high resolution respirometry

    Czech Academy of Sciences Publication Activity Database

    Pecina, Petr; Houšťková, H.; Mráček, Tomáš; Pecinová, Alena; Nůsková, Hana; Tesařová, M.; Hansíková, H.; Janota, J.; Zeman, J.; Houštěk, Josef

    2014-01-01

    Roč. 2, Dec (2014), s. 62-71 ISSN 2214-6474 R&D Projects: GA MZd(CZ) NT12370; GA ČR(CZ) GAP303/11/0970; GA ČR(CZ) GB14-36804G Institutional support: RVO:67985823 Keywords : lymphocytes * respirometry * oxidative phosphorylation * mitochondrial diseases * diagnostics Subject RIV: FG - Pediatrics

  5. Isolation and characterization of a Ca/sup 2 +/ carrier candidate from calf heart inner mitochondrial membrane

    Energy Technology Data Exchange (ETDEWEB)

    Jeng, A.Y.

    1979-01-01

    A protein was isolated from calf heart inner mitochondrial membrane with the aid of an electron paramagnetic resonance assay based on the relative binding properties of Ca/sup 2 +/, Mn/sup 2 +/, and Mg/sup 2 +/ to the protein. Partial delipidation of the protein was performed by using either the organic solvent extraction procedure or the silicic acid column chromatography. Control experiments indicated that the Ca/sup 2 +/ transport properties of the isolated protein were not due to the contaminating phospholipids. A complete delipidation procedure was developd by using Sephadex LH-20 column chromatography. Further characterization of the physical and chemical properties of the delipidated protein showed that delipidated protein becomes more hydrophobic in the presence of Ca/sup 2 +/ and alkaline pH in the organic solvent extraction experiments. Two possible models of calciphorin-mediated Ca/sup 2 +/ transport in mitochondria are proposed. (PCS)

  6. A defect in the thymidine kinase 2 gene causing isolated mitochondrial myopathy without mtDNA depletion.

    Science.gov (United States)

    Leshinsky-Silver, E; Michelson, M; Cohen, S; Ginsberg, M; Sadeh, M; Barash, V; Lerman-Sagie, T; Lev, D

    2008-07-01

    Isolated mitochondrial myopathies (IMM) are either due to primary defects in mtDNA, in nuclear genes that control mtDNA abundance and structure such as thymidine kinase 2 (TK2), or due to CoQ deficiency. Defects in the TK2 gene have been found to be associated with mtDNA depletion attributed to a depleted mitochondrial dNTP pool in non-dividing cells. We report an unusual case of IMM, homozygous for the H90N mutation in the TK2 gene but unlike other cases with the same mutation, does not demonstrate mtDNA depletion. The patient's clinical course is relatively mild and a muscle biopsy showed ragged red muscle fibers with a mild decrease in complexes I and an increase in complexes IV and II activities. This report extends the phenotypic expression of TK2 defects and suggests that all patients who present with an IMM even with normal quantities of mtDNA should be screened for TK2 mutations.

  7. TMEM70 mutations cause isolated ATP synthase deficiency and neonatal mitochondrial encephalocardiomyopathy

    Czech Academy of Sciences Publication Activity Database

    Čížková, Alena; Stránecký, V.; Mayr, J. A.; Tesařová, M.; Havlíčková, Vendula; Paul, Jan; Ivánek, R.; Kuss, A. W.; Hansíková, H.; Kaplanová, Vilma; Vrbacký, Marek; Hartmannová, H.; Nosková, L.; Honzík, T.; Drahota, Zdeněk; Magner, M.; Hejzlarová, Kateřina; Sperl, W.; Zeman, J.; Houštěk, Josef; Kmoch, S.

    2008-01-01

    Roč. 40, č. 11 (2008), s. 1288-1290 ISSN 1061-4036 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR GD305/08/H037; GA ČR(CZ) GD303/03/H065 Grant - others:Univerzita Karlova(CZ) 97807 Institutional research plan: CEZ:AV0Z50110509 Keywords : ATPase biogenesis * TMEM70 * mitochondrial disease Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 30.259, year: 2008

  8. Genetic variability among Trichuris ovis isolates from different hosts in Guangdong Province, China revealed by sequences of three mitochondrial genes.

    Science.gov (United States)

    Wang, Yan; Liu, Guo-Hua; Li, Jia-Yuan; Xu, Min-Jun; Ye, Yong-Gang; Zhou, Dong-Hui; Song, Hui-Qun; Lin, Rui-Qing; Zhu, Xing-Quan

    2013-02-01

    This study examined sequence variation in three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1), NADH dehydrogenase subunit 5 (nad5) and cytochrome b (cytb), among Trichuris ovis isolates from different hosts in Guangdong Province, China. A portion of the cox1 (pcox1), nad5 (pnad5) and cytb (pcytb) genes was amplified separately from individual whipworms by PCR, and was subjected to sequencing from both directions. The size of the sequences of pcox1, pnad5 and pcytb was 618, 240 and 464 bp, respectively. Although the intra-specific sequence variations within T. ovis were 0-0.8% for pcox1, 0-0.8% for pnad5 and 0-1.9% for pcytb, the inter-specific sequence differences among members of the genus Trichuris were significantly higher, being 24.3-26.5% for pcox1, 33.7-56.4% for pnad5 and 24.8-26.1% for pcytb, respectively. Phylogenetic analyses using combined sequences of pcox1, pnad5 and pcytb, with three different computational algorithms (maximum likelihood, maximum parsimony and Bayesian inference), indicated that all of the T. ovis isolates grouped together with high statistical support. These findings demonstrated the existence of intra-specific variation in mtDNA sequences among T. ovis isolates from different hosts, and have implications for studying molecular epidemiology and population genetics of T. ovis.

  9. Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae employing mitochondrial COI gene sequence data

    Directory of Open Access Journals (Sweden)

    Monte Tainá CC

    2012-11-01

    Full Text Available Abstract Background The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode’s main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI gene sequences. Methods The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship. Results The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8 from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, São Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7. Conclusion The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions.

  10. Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae) employing mitochondrial COI gene sequence data

    Science.gov (United States)

    2012-01-01

    Background The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode’s main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Methods The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship. Results The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8) from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, São Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7. Conclusion The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions. PMID:23130987

  11. Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae) employing mitochondrial COI gene sequence data.

    Science.gov (United States)

    Monte, Tainá C C; Simões, Raquel O; Oliveira, Ana Paula M; Novaes, Clodoaldo F; Thiengo, Silvana C; Silva, Alexandre J; Estrela, Pedro C; Maldonado, Arnaldo

    2012-11-06

    The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode's main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship. The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8) from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, São Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7. The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions.

  12. From outer space to Earth-The social significance of isolated and confined environment research in human space exploration

    Science.gov (United States)

    Tachibana, Koji; Tachibana, Shoichi; Inoue, Natsuhiko

    2017-11-01

    Human space exploration requires massive budgets every fiscal year. Especially under severe financial constraint conditions, governments are forced to justify to society why spending so much tax revenue for human space exploration is worth the cost. The value of human space exploration might be estimated in many ways, but its social significance and cost-effectiveness are two key ways to gauge that worth. Since these measures should be applied country by country because sociopolitical conditions differ in each country and must be taken into consideration, the study on the social significance of human space exploration must take the coloration of a case-study. This paper, focusing on the case of Japan with surveying Japanese literary and national documents as well as taking its sociopolitical conditions into account, examines the social significance of human space exploration. First, we give an overview of the circumstances surrounding Japan's human space exploration program. Derived from the statements of such relevant parties as scholars, journalists, policy makers, and astronauts, this overview indicates that the main concerns about human space exploration in Japan are its social significance and cost-effectiveness (Section 1). Next, an overview of behavioral science-an essential field for human space exploration (referred to in this paper as space behavioral science) that provides support for astronauts-is presented from the perspective of stress research in isolated and confined environments (Section 2). We then give two examples of where such knowledge from space behavioral science research has been applied to terrestrial isolated and confined environments. One is JAXA's support in 2009 for people who were vulnerable to infection by a new strain of flu and accordingly placed in an isolated and confined facility under the Infectious Disease Law and the Quarantine Law. The other is NASA's support in 2010 for Chilean mine workers who were trapped 700 m

  13. Outer magnetosphere

    International Nuclear Information System (INIS)

    Schardt, A.W.; Behannon, K.W.; Lepping, R.P.; Carbary, J.F.; Eviatar, A.; Siscoe, G.L.

    1984-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc

  14. Mitochondrial bioenergetics during the initiation of mercuric chloride-induced renal activity. II. Functional alterations of renal cortical mitochondria isolated after mercuric chloride treatment

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg, J.M. (Veterans Administration Medical Center, Ann Arbor, MI); Harding, P.G.; Humes, H.D.

    1982-01-01

    The mitochondrial functional defects occurring in the early stages of nephrotoxic renal injury secondary to mercuric chloride have been characterized. No loss of cellular integrity or major mitochondrial structural alterations occurred within the first 3 hr after a subcutaneous injection of 5 mg/kg of HgCl/sub 2/. At 3 h, levels of Hg/sup 2 +/ in renal cortex and isolated renal cortical mitochondria were 1.87 and 0.72 nmol/mg of protein, respectively. Much evidence suggested that this Hg/sup 2 +/ had reached the mitochondria in situ and not during the isolation process. Mitochondria isolated beginning 1 h after treatment with HgCl/sub 2/ showed depressed ADP uptake. At 2 h, inhibitions of State 3 and 2,4-dinitrophenol uncoupled respiration were detected. Inhibition of 2,4-dinitrophenol-activated mitochondrial ATPase activity was present when measured on mitochondria isolated at 3 h. These effects were not reversed by 2 mM dithioerythritol, 50 mg/ml of albumin or 5 mM MgCl/sub 2/. Analysis of the data in the context of information available on the in vitro effects of HgCl/sub 2/ (Weinberg, J.M., Harding, P.G., and Humes, H.D. (1982) J. Biol. Chem. 257, 60-67) indicated that the mitochondrial functional effects could not be attributed to interaction of the mitochondria with Hg/sup 2 +/ during their isolation. These studies implicate compromised mitochondrial bioenergetic function as one of the earliest intracellular effects of Hg/sup 2 +/ in the production of nephrotoxicity but suggest that the intracellular process involves events in addition to those seen with direct exposure of mitochondria to Hg/sup 2 +/ in vitro.

  15. Nuclear and mitochondrial DNA reveals isolation of imperilled grey nurse shark populations (Carcharias taurus).

    Science.gov (United States)

    Ahonen, H; Harcourt, R G; Stow, A J

    2009-11-01

    Loss of sharks and other upper-trophic marine predators has sparked worldwide concern for the stability of ocean ecosystems. The grey nurse (ragged-tooth or sand tiger) shark (Carcharias taurus) is Vulnerable on a global scale, Critically Endangered in Australia and presumed extinct in parts of its historical range. We used 193 muscle and fin samples collected from six extant populations to assess global mtDNA and microsatellite diversity and the degree of global population genetic structure. Control region mtDNA diversity was low in every population, and two populations (eastern Australia and Japan) contained only a single mtDNA haplotype. Genetic signatures of recent losses of genetic variation were not yet apparent at microsatellite loci, indicating that this low mtDNA variation is not a result of anthropogenic population declines. Population differentiation was substantial between each population pair except Brazil and South Africa, F(ST) values ranged from 0.050 to 0.699 and 0.100 to 1.00 for microsatellite and mitochondrial data respectively. Bayesian analysis clearly partitioned individuals into five of the populations from which they were sampled. Our data imply a low frequency of immigrant exchange among each of these regions and we suggest that each be recognized as a distinct evolutionary significant unit. In contrast to pelagic species such as whale shark and white shark that may cross ocean basins and where cooperative international efforts are necessary for conservation, grey nurse shark, like many coastal species, need to be managed regionally.

  16. Dependence of mitochondrial and cytosolic adenine nucleotides on oxygen partial pressure in isolated hepatocytes. Application of a new rapid high pressure filtration technique for fractionation.

    OpenAIRE

    Hummerich, H; de Groot, H; Noll, T; Soboll, S

    1988-01-01

    By using a new rapid high pressure filtration technique, mitochondrial and cytosolic ATP and ADP contents were determined in isolated hepatocytes at different oxygen partial pressures. At 670 mmHg, subcellular adenine nucleotide contents and ATP/ADP ratios were comparable with values obtained with the digitonin fractionation technique. However at lower oxygen partial pressure ADP appears to be rephosphorylated during digitonin fractionation whereas with high pressure filtration fractionation ...

  17. Mitochondrial shaping cuts.

    Science.gov (United States)

    Escobar-Henriques, Mafalda; Langer, Thomas

    2006-01-01

    A broad range of cellular processes are regulated by proteolytic events. Proteolysis has now also been established to control mitochondrial morphology which results from the balanced action of fusion and fission. Two out of three known core components of the mitochondrial fusion machinery are under proteolytic control. The GTPase Fzo1 in the outer membrane of mitochondria is degraded along two independent proteolytic pathways. One controls mitochondrial fusion in vegetatively growing cells, the other one acts upon mating factor-induced cell cycle arrest. Fusion also depends on proteolytic processing of the GTPase Mgm1 by the rhomboid protease Pcp1 in the inner membrane of mitochondria. Functional links of AAA proteases or other proteolytic components to mitochondrial dynamics are just emerging. This review summarises the current understanding of regulatory roles of proteolytic processes for mitochondrial plasticity.

  18. Mitofilin complexes : conserved organizers of mitochondrial membrane architecture

    NARCIS (Netherlands)

    Zerbes, Ralf M.; van der Klei, Ida J.; Veenhuis, Marten; Pfanner, Nikolaus; van der Laan, Martin; Bohnert, Maria

    2012-01-01

    Mitofilin proteins are crucial organizers of mitochondrial architecture. They are located in the inner mitochondrial membrane and interact with several protein complexes of the outer membrane, thereby generating contact sites between the two membrane systems of mitochondria. Within the inner

  19. Mitochondrial ceramide-rich macrodomains functionalize Bax upon irradiation.

    Directory of Open Access Journals (Sweden)

    Hyunmi Lee

    Full Text Available Evidence indicates that Bax functions as a "lipidic" pore to regulate mitochondrial outer membrane permeabilization (MOMP, the apoptosis commitment step, through unknown membrane elements. Here we show mitochondrial ceramide elevation facilitates MOMP-mediated cytochrome c release in HeLa cells by generating a previously-unrecognized mitochondrial ceramide-rich macrodomain (MCRM, which we visualize and isolate, into which Bax integrates.MCRMs, virtually non-existent in resting cells, form upon irradiation coupled to ceramide synthase-mediated ceramide elevation, optimizing Bax insertion/oligomerization and MOMP. MCRMs are detected by confocal microscopy in intact HeLa cells and isolated biophysically as a light membrane fraction from HeLa cell lysates. Inhibiting ceramide generation using a well-defined natural ceramide synthase inhibitor, Fumonisin B1, prevented radiation-induced Bax insertion, oligomerization and MOMP. MCRM deconstruction using purified mouse hepatic mitochondria revealed ceramide alone is non-apoptogenic. Rather Bax integrates into MCRMs, oligomerizing therein, conferring 1-2 log enhanced cytochrome c release. Consistent with this mechanism, MCRM Bax isolates as high molecular weight "pore-forming" oligomers, while non-MCRM membrane contains exclusively MOMP-incompatible monomeric Bax.Our recent studies in the C. elegans germline indicate that mitochondrial ceramide generation is obligate for radiation-induced apoptosis, although a mechanism for ceramide action was not delineated. Here we demonstrate that ceramide, generated in the mitochondrial outer membrane of mammalian cells upon irradiation, forms a platform into which Bax inserts, oligomerizes and functionalizes as a pore. We posit conceptualization of ceramide as a membrane-based stress calibrator, driving membrane macrodomain organization, which in mitochondria regulates intensity of Bax-induced MOMP, and is pharmacologically tractable in vitro and in vivo.

  20. Spitzer/IRAC view of Sh 2-284. Searching for evidence of triggered star formation in an isolated region in the outer Milky Way

    NARCIS (Netherlands)

    Puga, E.; Hony, S.; Neiner, C.; Lenorzer, A.; Hubert, A.M.; Waters, L.B.F.M.; Cusano, F.; Ripepi, V.

    2009-01-01

    Aims. Using Spitzer/IRAC observations of a region to be observed by the CoRoT satellite, we have unraveled a new complex star-forming region at low metallicity in the outer Galaxy. We perform a study of S284 in order to outline the chain of events in this star-forming region. Methods. We used

  1. Mitochondrial respiratory control is lost during growth factor deprivation.

    Science.gov (United States)

    Gottlieb, Eyal; Armour, Sean M; Thompson, Craig B

    2002-10-01

    The ability of cells to maintain a bioenergetically favorable ATP/ADP ratio confers a tight balance between cellular events that consume ATP and the rate of ATP production. However, after growth factor withdrawal, the cellular ATP/ADP ratio declines. To investigate these changes, mitochondria from growth factor-deprived cells isolated before the onset of apoptosis were characterized in vitro. Mitochondria from growth factor-deprived cells have lost their ability to undergo matrix condensation in response to ADP, which is accompanied by a failure to perform ADP-coupled respiration. At the time of analysis, mitochondria from growth factor-deprived cells were not depleted of cytochrome c and cytochrome c-dependent respiration was unaffected, demonstrating that the inhibition of the respiratory rate is not due to loss of cytochrome c. Agents that disrupt the mitochondrial outer membrane, such as digitonin, or maintain outer membrane exchange of adenine nucleotide, such as Bcl-x(L), restored ADP-dependent control of mitochondrial respiration. Together, these data suggest that the regulation of mitochondrial outer membrane permeability contributes to respiratory control.

  2. Comparative studies of Yersinia pestis outer membrane isolation techniques and their potential use in plague epidemiology Estudo comparativo de técnicas de isolamento de membrana externa de Yersinia pestis e seu uso na epidemiologia da peste

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme Coutinho Abath

    1990-04-01

    Full Text Available In the present study three techniques for obtaining outer membrane enriched fractions from Yersinia pestis were evaluated. The techniques analysed were: differential solubilization of the cytoplasmic membrane with Sarkosyl or Triton X-100, and centrifugation in sucrose density gradients. The sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE of outer membrane isolated by the different methods resulted in similar protein patterns. The measurement of NADH-dehydrogenase and succinate dehydrogenase (inner membrane enzymes indicated that the outer membrane preparations obtained by the three methods were pure enough for analytical studies. In addition, preliminary evidences on the potential use of outer membrane proteins for the identification of geographic variants of Y. pestis wild isolates are presented.No presente estudo três técnicas para isolamento de frações enriquecidas em membrana externa de Y. pestis foram avaliadas. As técnicas utilizadas foram: centrifugação em gradiente de densidade em sacarose e solubilização diferencial com Sarkosyl ou Triton X-100. A análise por eletroforese em gel de poliacrilamida na presença de dodecil sulfato de sódio (SDS-PAGE das membranas externas extraídas pelos diferentes métodos evidenciou perfis protéicos semelhantes. A determinação das atividades de NADH-desidrogenase e succinato-desidrogenase (enzimas de membrana interna indicou que todas as preparações estudadas eram adequadas a estudos analíticos. Obteve-se evidências preliminares sobre o possível uso de perfis protéicos de membrana externa na identificação de variantes geográficos entre isolados selvagens de Y. pestis.

  3. Patterns in nuclear and mitochondrial DNA reveal historical and recent isolation in the black-tailed godwit (Limosa limosa)

    NARCIS (Netherlands)

    Trimbos, Krijn B.; Doorenweerd, Camiel; Kraaijeveld, Ken; Musters, C.J.M.; Groen, Niko M.; Knijff, Peter de; Piersma, Theunis; de Snoo, Geert R.

    2014-01-01

    On the basis of morphological differences, three subspecies of Black-tailed Godwit (Limosa limosa) have been recognized (L. l. limosa, L. l. islandica and L. l. melanuroides). In previous studies mitochondrial DNA (mtDNA) sequence data showed minimal genetic divergence between the three subspecies

  4. A free-living amoeba with unusual pattern of mitochondrial structure isolated from Atlantic salmon, Salmo salar L

    Czech Academy of Sciences Publication Activity Database

    Dyková, Iva; Veverková, Marie; Fiala, Ivan; Macháčková, Blanka

    2002-01-01

    Roč. 41, - (2002), s. 415-419 ISSN 0065-1583 R&D Projects: GA AV ČR IAA6022202 Institutional research plan: CEZ:AV0Z6022909 Keywords : free-living amoeba * mitochondrial cristae * Salmo salar Subject RIV: EA - Cell Biology Impact factor: 0.446, year: 2002

  5. Patterns in Nuclear and Mitochondrial DNA Reveal Historical and Recent Isolation in the Black-Tailed Godwit (Limosa limosa)

    NARCIS (Netherlands)

    Trimbos, K.B.; Doorenweerd, C.; Kraaijeveld, K.; Musters, C.J.M.; Groen, N.M.; Kniff, de P.; Piersma, T.; Snoo, de G.R.

    2014-01-01

    On the basis of morphological differences, three subspecies of Black-tailed Godwit (Limosa limosa) have been recognized (L. l. limosa, L. l. islandica and L. l. melanuroides). In previous studies mitochondrial DNA (mtDNA) sequence data showed minimal genetic divergence between the three subspecies

  6. Patterns in Nuclear and Mitochondrial DNA Reveal Historical and Recent Isolation in the Black-Tailed Godwit (

    NARCIS (Netherlands)

    Trimbos, K.B.; Doorenweerd, C.; Kraaijeveld, K.; Musters, C.J.M.; Groen, N.M.; de Knijff, P.; Piersma, T.; de Snoo, G.R.

    2014-01-01

    On the basis of morphological differences, three subspecies of Black-tailed Godwit (Limosa limosa) have been recognized (L. l. limosa, L. l. islandica and L. l. melanuroides). In previous studies mitochondrial DNA (mtDNA) sequence data showed minimal genetic divergence between the three subspecies

  7. Relative mitochondrial membrane potential and [Ca2+]i in type I cells isolated from the rabbit carotid body.

    Science.gov (United States)

    Duchen, M R; Biscoe, T J

    1992-05-01

    1. In the accompanying paper (Duchen & Biscoe, 1992) we have described graded changes in autofluorescence derived from mitochondrial NAD(P)H in type I cells of the carotid body in response to changes of PO2 over a physiologically significant range. These observations suggest that mitochondrial function in these cells is unusually sensitive to oxygen and could play a role in oxygen sensing. We have now explored further the relationships between hypoxia, mitochondrial membrane potential (delta psi m) and [Ca2+]i. 2. The fluorescence of Rhodamine 123 (Rh 123) accumulated within mitochondria is quenched by delta psi m. Mitochondrial depolarization thus increases the fluorescence signal. Blockade of electron transport (CN-, anoxia, rotenone) and uncoupling agents (e.g. carbonyl cyanide p-trifluoromethoxy-phenylhydrazone; FCCP) increased fluorescence by up to 80-120%, while fluorescence was reduced by blockade of the F0 proton channel of the mitochondrial ATP synthase complex (oligomycin). 3. delta psi m depolarized rapidly with anoxia, and was usually completely dissipated within 1-2 min. The depolarization of delta psi m with anoxia (or CN-) and repolarization on reoxygenation both followed a time course well characterized as the sum of two exponential processes. Oligomycin (0.2-2 micrograms/ml) hyperpolarized delta psi m and abolished the slower components of both the depolarization with anoxia and of the subsequent repolarization. These data (i) illustrate the role of the F1-F0 ATP synthetase in slowing the rate of dissipation of delta psi m on cessation of electron transport, (ii) confirm blockade of the ATP synthetase by oligomycin at these concentrations, and (iii) indicate significant accumulation of intramitochondrial ADP during 1-2 min of anoxia. 4. Depolarization of delta psi m was graded with graded changes in PO2 below about 60 mmHg. The stimulus-response curves thus constructed strongly resemble those for [Ca2+]i and NAD(P)H with PO2. The change in delta

  8. Molecular basis for mitochondrial signaling

    CERN Document Server

    2017-01-01

    This book covers recent advances in the study of structure, function, and regulation of metabolite, protein and ion translocating channels, and transporters in mitochondria. A wide array of cutting-edge methods are covered, ranging from electrophysiology and cell biology to bioinformatics, as well as structural, systems, and computational biology. At last, the molecular identity of two important channels in the mitochondrial inner membrane, the mitochondrial calcium uniporter and the mitochondrial permeability transition pore have been established. After years of work on the physiology and structure of VDAC channels in the mitochondrial outer membrane, there have been multiple discoveries on VDAC permeation and regulation by cytosolic proteins. Recent breakthroughs in structural studies of the mitochondrial cholesterol translocator reveal a set of novel unexpected features and provide essential clues for defining therapeutic strategies. Molecular Basis for Mitochondrial Signaling covers these and many more re...

  9. Mitochondrial Disease

    OpenAIRE

    Bulent Kurt; Turgut Topal

    2013-01-01

    Mitochondria are the major energy source of cells. Mitochondrial disease occurs due to a defect in mitochondrial energy production. A valuable energy production in mitochondria depend a healthy interconnection between nuclear and mitochondrial DNA. A mutation in nuclear or mitochondrial DNA may cause abnormalities in ATP production and single or multiple organ dysfunctions, secondarily. In this review, we summarize mitochondrial physiology, mitochondrial genetics, and clinical expression and ...

  10. Contribution of liver mitochondrial membrane-bound glutathione transferase to mitochondrial permeability transition pores

    International Nuclear Information System (INIS)

    Hossain, Quazi Sohel; Ulziikhishig, Enkhbaatar; Lee, Kang Kwang; Yamamoto, Hideyuki; Aniya, Yoko

    2009-01-01

    We recently reported that the glutathione transferase in rat liver mitochondrial membranes (mtMGST1) is activated by S-glutathionylation and the activated mtMGST1 contributes to the mitochondrial permeability transition (MPT) pore and cytochrome c release from mitochondria [Lee, K.K., Shimoji, M., Quazi, S.H., Sunakawa, H., Aniya, Y., 2008. Novel function of glutathione transferase in rat liver mitochondrial membrane: role for cytochrome c release from mitochondria. Toxcol. Appl. Pharmacol. 232, 109-118]. In the present study we investigated the effect of reactive oxygen species (ROS), generator gallic acid (GA) and GST inhibitors on mtMGST1 and the MPT. When rat liver mitochondria were incubated with GA, mtMGST1 activity was increased to about 3 fold and the increase was inhibited with antioxidant enzymes and singlet oxygen quenchers including 1,4-diazabicyclo [2,2,2] octane (DABCO). GA-mediated mtMGST1 activation was prevented by GST inhibitors such as tannic acid, hematin, and cibacron blue and also by cyclosporin A (CsA). In addition, GA induced the mitochondrial swelling which was also inhibited by GST inhibitors, but not by MPT inhibitors CsA, ADP, and bongkrekic acid. GA also released cytochrome c from the mitochondria which was inhibited completely by DABCO, moderately by GST inhibitors, and somewhat by CsA. Ca 2+ -mediated mitochondrial swelling and cytochrome c release were inhibited by MPT inhibitors but not by GST inhibitors. When the outer mitochondrial membrane was isolated after treatment of mitochondria with GA, mtMGST1 activity was markedly increased and oligomer/aggregate of mtMGST1 was observed. These results indicate that mtMGST1 in the outer mitochondrial membrane is activated by GA through thiol oxidation leading to protein oligomerization/aggregation, which may contribute to the formation of ROS-mediated, CsA-insensitive MPT pore, suggesting a novel mechanism for regulation of the MPT by mtMGST1

  11. Phenylpropanoids isolated from Piper sarmentosum Roxb. induce apoptosis in breast cancer cells through reactive oxygen species and mitochondrial-dependent pathways.

    Science.gov (United States)

    Hematpoor, Arshia; Paydar, Mohammadjavad; Liew, Sook Yee; Sivasothy, Yasodha; Mohebali, Nooshin; Looi, Chung Yeng; Wong, Won Fen; Azirun, Mohd Sofian; Awang, Khalijah

    2018-01-05

    The aim of the present study is to isolate bioactive compounds from the roots of Piper sarmentosum and examine the mechanism of action using human breast cancer cell line (MDA-MB-231). Bioassay guided-fractionation of methanolic extract led to the isolation of asaricin (1) and isoasarone (2). Asaricin (1) and isoasarone (2) had significant cytotoxicity towards MDA-MB-231. MCF-10A (human normal breast epithelial cells) cells are less sensitive than MDA-MB-231, but they respond to the treatment with the same unit of measurement. Both compounds increase reactive oxygen species (ROS), decrease mitochondrial membrane potential (MMP) and enhance cytochrome c release in treated MDA-MB-231 cells. Isoasarone (2) markedly elevated caspase -8 and -3/7 activities and caused a decline in nuclear NF-κB translocation, suggesting extrinsic, death receptor-linked apoptosis pathway. Quantitative PCR results of MDA-MB-231 treated with asaricin (1) and isoasarone (2) showed altered expression of Bcl-2: Bax level. The inhibitory potency of these isolates may support the therapeutic uses of these compounds in breast cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Protective effects of physical exercise on MDMA-induced cognitive and mitochondrial impairment.

    Science.gov (United States)

    Taghizadeh, Ghorban; Pourahmad, Jalal; Mehdizadeh, Hajar; Foroumadi, Alireza; Torkaman-Boutorabi, Anahita; Hassani, Shokoufeh; Naserzadeh, Parvaneh; Shariatmadari, Reyhaneh; Gholami, Mahdi; Rouini, Mohammad Reza; Sharifzadeh, Mohammad

    2016-10-01

    Debate continues about the effect of 3, 4-methylenedioxymethamphetamine (MDMA) on cognitive and mitochondrial function through the CNS. It has been shown that physical exercise has an important protective effect on cellular damage and death. Therefore, we investigated the effect of physical exercise on MDMA-induced impairments of spatial learning and memory as well as MDMA effects on brain mitochondrial function in rats. Male wistar rats underwent short-term (2 weeks) or long-term (4 weeks) treadmill exercise. After completion of exercise duration, acquisition and retention of spatial memory were evaluated by Morris water maze (MWM) test. Rats were intraperitoneally (I.P) injected with MDMA (5, 10, and 15mg/kg) 30min before the first training trial in 4 training days of MWM. Different parameters of brain mitochondrial function were measured including the level of ROS production, mitochondrial membrane potential (MMP), mitochondrial swelling, mitochondrial outermembrane damage, the amount of cytochrome c release from the mitochondria, and ADP/ATP ratio. MDMA damaged the spatial learning and memory in a dose-dependent manner. Brain mitochondria isolated from the rats treated with MDMA showed significant increase in ROS formation, collapse of MMP, mitochondrial swelling, and outer membrane damage, cytochrome c release from the mitochondria, and finally increased ADP/ATP ratio. This study also found that physical exercise significantly decreased the MDMA-induced impairments of spatial learning and memory and also mitochondrial dysfunction. The results indicated that MDMA-induced neurotoxicity leads to brain mitochondrial dysfunction and subsequent oxidative stress is followed by cognitive impairments. However, physical exercise could reduce these deleterious effects of MDMA through protective effects on brain mitochondrial function. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Demographics, diet, movements, and survival of an isolated, unmanaged raccoon Procyon lotor (Procyonidae, Carnivora) population on the Outer Banks of North Carolina

    Science.gov (United States)

    Parsons, Arielle Waldstein; Simons, Theodore R.; O'Connell, Allan F.; Stoskopf, Michael K.

    2012-01-01

    Raccoons (Procyon lotor) are highly adaptable meso-carnivores that inhabit many environments, including the Atlantic barrier islands, where their role as predators of declining, beach-nesting bird and turtle species is of particular interest. Population models that improve our understanding of predator-prey dynamics are receiving increasing attention in the literature; however, their effective application requires site-specific information on population parameters. We studied an unharvested raccoon population on the Outer Banks of North Carolina and evaluated spatial and seasonal differences in a number of population/demographic factors of raccoons inhabiting areas of high and low human activity. Raccoons denned and foraged primarily in salt marsh habitats but shifted their movements in response to changes in seasonal resource conditions. The population was skewed toward older animals and exhibited delayed breeding, typical of populations at high density with few sources of mortality. Diet and movement analysis indicated shorebird and turtle predation was attributed to a small number of individual raccoons. Although seasonal resources appeared adequate to sustain a high population density of raccoons, poor body condition and low recruitment suggested a population near carrying capacity.

  14. Mitochondrial localization of the low level p53 protein in proliferative cells

    Energy Technology Data Exchange (ETDEWEB)

    Ferecatu, Ioana; Bergeaud, Marie; Rodriguez-Enfedaque, Aida; Le Floch, Nathalie [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Oliver, Lisa [INSERM U601, Universite de Nantes, Faculte de Medecine, Nantes Cedex (France); Rincheval, Vincent; Renaud, Flore [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Vallette, Francois M. [INSERM U601, Universite de Nantes, Faculte de Medecine, Nantes Cedex (France); Mignotte, Bernard [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Vayssiere, Jean-Luc, E-mail: jean-luc.vayssiere@uvsq.fr [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France)

    2009-10-02

    p53 protein plays a central role in suppressing tumorigenesis by inducing cell cycle arrest or apoptosis through transcription-dependent and -independent mechanisms. Emerging publications suggest that following stress, a fraction of p53 translocates to mitochondria to induce cytochrome c release and apoptosis. However, the localization of p53 under unstressed conditions remains largely unexplored. Here we show that p53 is localized at mitochondria in absence of apoptotic stimuli, when cells are proliferating, localization observed in various cell types (rodent and human). This is also supported by acellular assays in which p53 bind strongly to mitochondria isolated from rat liver. Furthermore, the mitochondria subfractionation study and the alkaline treatment of the mitochondrial p53 revealed that the majority of mitochondrial p53 is present in the membranous compartments. Finally, we identified VDAC, a protein of the mitochondrial outer-membrane, as a putative partner of p53 in unstressed/proliferative cells.

  15. Mitochondrial localization of the low level p53 protein in proliferative cells

    International Nuclear Information System (INIS)

    Ferecatu, Ioana; Bergeaud, Marie; Rodriguez-Enfedaque, Aida; Le Floch, Nathalie; Oliver, Lisa; Rincheval, Vincent; Renaud, Flore; Vallette, Francois M.; Mignotte, Bernard; Vayssiere, Jean-Luc

    2009-01-01

    p53 protein plays a central role in suppressing tumorigenesis by inducing cell cycle arrest or apoptosis through transcription-dependent and -independent mechanisms. Emerging publications suggest that following stress, a fraction of p53 translocates to mitochondria to induce cytochrome c release and apoptosis. However, the localization of p53 under unstressed conditions remains largely unexplored. Here we show that p53 is localized at mitochondria in absence of apoptotic stimuli, when cells are proliferating, localization observed in various cell types (rodent and human). This is also supported by acellular assays in which p53 bind strongly to mitochondria isolated from rat liver. Furthermore, the mitochondria subfractionation study and the alkaline treatment of the mitochondrial p53 revealed that the majority of mitochondrial p53 is present in the membranous compartments. Finally, we identified VDAC, a protein of the mitochondrial outer-membrane, as a putative partner of p53 in unstressed/proliferative cells.

  16. Saponins isolated from Asparagus induce apoptosis in human hepatoma cell line HepG2 through a mitochondrial-mediated pathway

    Science.gov (United States)

    Ji, Y.; Ji, C.; Yue, L.; Xu, H.

    2012-01-01

    Objective Many scientific studies have shown that Asparagus officinalis has an antitumour effect and enhances human immunity, but the active components and the antitumour mechanisms are unclear. We investigated the effects of saponins isolated from Asparagus on proliferation and apoptosis in the human hepatoma cell line HepG2. Methods HepG2 cells were treated with varying concentrations of Asparagus saponins at various times. Using mtt and flow cytometry assays, we evaluated the effects of Asparagus saponins on the growth and apoptosis of HepG2 cells. Transmission electron microscopy was used to observe the morphology of cell apoptosis. Confocal laser scanning microscopy was used to analyze intracellular calcium ion concentration, mitochondrial permeability transition pore (mptp), and mitochondrial membrane potential (mmp). Spectrophotometry was applied to quantify the activity of caspase-9 and caspase-3. Flow cytometry was used to investigate the levels of reactive oxygen species (ros) and pH, and the expressions of Bcl2, Bax, CytC, and caspase-3, in HepG2 cells. Results Asparagus saponins inhibited the growth of HepG2 cells in a dose-dependent manner. The median inhibitory concentration (IC50) was 101.15 mg/L at 72 hours. The apoptosis morphology at 72 hours of treatment was obvious, showing cell protuberance, concentrated cytoplasm, and apoptotic bodies. The apoptotic rates at 72 hours were 30.9%, 51.7%, and 62.1% (for saponin concentrations of 50 mg/L, 100 mg/L, 200 mg/L). Treatment with Asparagus saponins for 24 hours increased the intracellular level of ros and Ca2+, lowered the pH, activated intracellular mptp, and decreased mmp in a dose-dependent manner. Treatment also increased the activity of caspase-9 and caspase-3, downregulated the expression of Bcl2, upregulated the expression of Bax, and induced release of CytC and activation of caspase-3. Conclusions Asparagus saponins induce apoptosis in HepG2 cells through a mitochondrial-mediated and caspase

  17. Mitochondrial shape governs BAX-induced membrane permeabilization and apoptosis.

    Science.gov (United States)

    Renault, Thibaud T; Floros, Konstantinos V; Elkholi, Rana; Corrigan, Kelly-Ann; Kushnareva, Yulia; Wieder, Shira Y; Lindtner, Claudia; Serasinghe, Madhavika N; Asciolla, James J; Buettner, Christoph; Newmeyer, Donald D; Chipuk, Jerry E

    2015-01-08

    Proapoptotic BCL-2 proteins converge upon the outer mitochondrial membrane (OMM) to promote mitochondrial outer membrane permeabilization (MOMP) and apoptosis. Here we investigated the mechanistic relationship between mitochondrial shape and MOMP and provide evidence that BAX requires a distinct mitochondrial size to induce MOMP. We utilized the terminal unfolded protein response pathway to systematically define proapoptotic BCL-2 protein composition after stress and then directly interrogated their requirement for a productive mitochondrial size. Complementary biochemical, cellular, in vivo, and ex vivo studies reveal that Mfn1, a GTPase involved in mitochondrial fusion, establishes a mitochondrial size that is permissive for proapoptotic BCL-2 family function. Cells with hyperfragmented mitochondria, along with size-restricted OMM model systems, fail to support BAX-dependent membrane association and permeabilization due to an inability to stabilize BAXα9·membrane interactions. This work identifies a mechanistic contribution of mitochondrial size in dictating BAX activation, MOMP, and apoptosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Hybridization, mitochondrial DNA phylogeography, and prediction of the early stages of reproductive isolation: lessons from New Zealand cicadas (genus Kikihia).

    Science.gov (United States)

    Marshall, David C; Hill, Kathy B R; Cooley, John R; Simon, Chris

    2011-07-01

    One of the major tenets of the modern synthesis is that genetic differentiation among subpopulations is translated over time into genetic differentiation among species. Phylogeographic exploration is therefore essential to the study of speciation because it can reveal the presence of subpopulations that may go on to become species or that may already represent cryptic species. Acoustic species-specific mating signals provide a significant advantage for the recognition of cryptic or incipient species. Because the majority of species do not have such easily recognized premating signals, data from acoustically signaling species can serve as a valuable heuristic tool. Acoustic signals are also convenient tools for recognizing hybridization events. Here, we demonstrate that evidence of hybridization in the form of intermediate song phenotypes is present in many contact zones between species of the New Zealand grass cicadas of the Kikihia muta species complex and that recurring mitochondrial DNA (mtDNA) introgression has created misleading patterns that make it difficult to identify certain taxa using song or mtDNA alone. In one case, introgression appears to have occurred between allopatric taxa by dispersal of introgressed populations of an intermediary species ("hybridization by proxy"). We also present a comparison of mtDNA-tree- and song-based taxonomies obtained for the K. muta complex. We find that 12 mtDNA candidate species are identified using shifts in phylogenetic branching rate found by a single-threshold mixed Yule-coalescent lineage model, while only 7 candidate species are identified using songs. Results from the Yule-coalescent model are dependent on factors such as the number of modeled thresholds and the inclusion of duplicate haplotypes. Genetic distances within song species reach a maximum at about 0.028 substitutions/site when likely cases of hybridization and introgression are excluded. Large genetic breaks or "gaps" are not observed between some

  19. Subamolide B Isolated from Medicinal Plant Cinnamomum subavenium Induces Cytotoxicity in Human Cutaneous Squamous Cell Carcinoma Cells through Mitochondrial and CHOP-Dependent Cell Death Pathways

    Directory of Open Access Journals (Sweden)

    Shu-Yi Yang

    2013-01-01

    Full Text Available Subamolide B is a butanolide isolated from Cinnamomum subavenium, a medicinal plant traditionally used to treat various ailments including carcinomatous swelling. We herein reported for the first time that subamolide B potently induced cytotoxicity against diverse human skin cancer cell lines while sparing nonmalignant cells. Mechanistic studies on human cutaneous squamous cell carcinoma (SCC cell line SCC12 highlighted the involvement of apoptosis in subamolide B-induced cytotoxicity, as evidenced by the activation of caspases-8, -9, -4, and -3, the increase in annexin V-positive population, and the partial restoration of cell viability by cotreatment with the pan-caspase inhibitor z-VAD-fmk. Additionally, subamolide B evoked cell death pathways mediated by FasL/Fas, mitochondria, and endoplasmic reticulum (ER stress, as supported by subamolide B-induced FasL upregulation, BCL-2 suppression/cytosolic release of cytochrome c, and UPR activation/CHOP upregulation, respectively. Noteworthy, ectopic expression of c-FLIPL or dominant-negative mutant of FADD failed to impair subamolide B-induced cytotoxicity, whereas BCL-2 overexpression or CHOP depletion greatly rescued subamolide B-stimulated cells. Collectively, these results underscored the central role of mitochondrial and CHOP-mediated cell death pathways in subamolide B-induced cytotoxicity. Our findings further implicate the potential of subamolide B for cutaneous SCC therapy or as a lead compound for developing novel chemotherapeutic agents.

  20. Genetic diversity and relatedness of Fasciola spp. isolates from different hosts and geographic regions revealed by analysis of mitochondrial DNA sequences.

    Science.gov (United States)

    Ai, L; Weng, Y B; Elsheikha, H M; Zhao, G H; Alasaad, S; Chen, J X; Li, J; Li, H L; Wang, C R; Chen, M X; Lin, R Q; Zhu, X Q

    2011-09-27

    The present study examined sequence variability in a portion of the mitochondrial cytochrome c oxidase subunit 1 (pcox1) and NADH dehydrogenase subunits 4 and 5 (pnad4 and pnad5) among 39 isolates of Fasciola spp., from different hosts from China, Niger, France, the United States of America, and Spain; and their phylogenetic relationships were re-constructed. Intra-species sequence variations were 0.0-1.1% for pcox1, 0.0-2.7% for pnad4, and 0.0-3.3% for pnad5 for Fasciola hepatica; 0.0-1.8% for pcox1, 0.0-2.5% for pnad4, and 0.0-4.2% for pnad5 for Fasciola gigantica, and 0.0-0.9% for pcox1, 0.0-0.2% for pnad4, and 0.0-1.1% for pnad5 for the intermediate Fasciola form. Whereas, nucleotide differences were 2.1-2.7% for pcox1, 3.1-3.3% for pnad4, and 4.2-4.8% for pnad5 between F. hepatica and F. gigantica; were 1.3-1.5% for pcox1, 2.1-2.9% for pnad4, 3.1-3.4% for pnad5 between F. hepatica and the intermediate form; and were 0.9-1.1% for pcox1, 1.4-1.8% for pnad4, 2.2-2.4% for pnad5 between F. gigantica and the intermediate form. Phylogenetic analysis based on the combined sequences of pcox1, pnad4 and pnad5 revealed distinct groupings of isolates of F. hepatica, F. gigantica, or the intermediate Fasciola form irrespective of their origin, demonstrating the usefulness of the mtDNA sequences for the delineation of Fasciola species, and reinforcing the genetic evidence for the existence of the intermediate Fasciola form. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Mitochondrial disease and endocrine dysfunction.

    Science.gov (United States)

    Chow, Jasmine; Rahman, Joyeeta; Achermann, John C; Dattani, Mehul T; Rahman, Shamima

    2017-02-01

    Mitochondria are critical organelles for endocrine health; steroid hormone biosynthesis occurs in these organelles and they provide energy in the form of ATP for hormone production and trafficking. Mitochondrial diseases are multisystem disorders that feature defective oxidative phosphorylation, and are characterized by enormous clinical, biochemical and genetic heterogeneity. To date, mitochondrial diseases have been found to result from >250 monogenic defects encoded across two genomes: the nuclear genome and the ancient circular mitochondrial genome located within mitochondria themselves. Endocrine dysfunction is often observed in genetic mitochondrial diseases and reflects decreased intracellular production or extracellular secretion of hormones. Diabetes mellitus is the most frequently described endocrine disturbance in patients with inherited mitochondrial diseases, but other endocrine manifestations in these patients can include growth hormone deficiency, hypogonadism, adrenal dysfunction, hypoparathyroidism and thyroid disease. Although mitochondrial endocrine dysfunction frequently occurs in the context of multisystem disease, some mitochondrial disorders are characterized by isolated endocrine involvement. Furthermore, additional monogenic mitochondrial endocrine diseases are anticipated to be revealed by the application of genome-wide next-generation sequencing approaches in the future. Understanding the mitochondrial basis of endocrine disturbance is key to developing innovative therapies for patients with mitochondrial diseases.

  2. Postzygotic isolation involves strong mitochondrial and sex-specific effects in Tigriopus californicus, a species lacking heteromorphic sex chromosomes.

    Science.gov (United States)

    Foley, B R; Rose, C G; Rundle, D E; Leong, W; Edmands, S

    2013-11-01

    Detailed studies of the genetics of speciation have focused on a few model systems, particularly Drosophila. The copepod Tigriopus californicus offers an alternative that differs from standard animal models in that it lacks heteromorphic chromosomes (instead, sex determination is polygenic) and has reduced opportunities for sexual conflict, because females mate only once. Quantitative trait loci (QTL) mapping was conducted on reciprocal F2 hybrids between two strongly differentiated populations, using a saturated linkage map spanning all 12 autosomes and the mitochondrion. By comparing sexes, a possible sex ratio distorter was found but no sex chromosomes. Although studies of standard models often find an excess of hybrid male sterility factors, we found no QTL for sterility and multiple QTL for hybrid viability (indicated by non-Mendelian adult ratios) and other characters. Viability problems were found to be stronger in males, but the usual explanations for weaker hybrid males (sex chromosomes, sensitivity of spermatogenesis, sexual selection) cannot fully account for these male viability problems. Instead, higher metabolic rates may amplify deleterious effects in males. Although many studies of standard speciation models find the strongest genetic incompatibilities to be nuclear-nuclear (specifically X chromosome-autosome), we found the strongest deleterious interaction in this system was mito-nuclear. Consistent with the snowball theory of incompatibility accumulation, we found that trigenic interactions in this highly divergent cross were substantially more frequent (>6×) than digenic interactions. This alternative system thus allows important comparisons to studies of the genetics of reproductive isolation in more standard model systems.

  3. The Outer Space Treaty

    Science.gov (United States)

    Johnson, Christopher Daniel

    2018-01-01

    Negotiated at the United Nations and in force since 1967, the Outer Space Treaty has been ratified by over 100 countries and is the most important and foundational source of space law. The treaty, whose full title is "Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies," governs all of humankind's activities in outer space, including activities on other celestial bodies and many activities on Earth related to outer space. All space exploration and human spaceflight, planetary sciences, and commercial uses of space—such as the global telecommunications industry and the use of space technologies such as position, navigation, and timing (PNT), take place against the backdrop of the general regulatory framework established in the Outer Space Treaty. A treaty is an international legal instrument which balances rights and obligations between states, and exists as a kind of mutual contract of shared understandings, rights, and responsibilities between them. Negotiated and drafted during the Cold War era of heightened political tensions, the Outer Space Treaty is largely the product of efforts by the United States and the USSR to agree on certain minimum standards and obligations to govern their competition in "conquering" space. Additionally, the Outer Space Treaty is similar to other treaties, including treaties governing the high seas, international airspace, and the Antarctic, all of which govern the behavior of states outside of their national borders. The treaty is brief in nature and only contains 17 articles, and is not comprehensive in addressing and regulating every possible scenario. The negotiating states knew that the Outer Space Treaty could only establish certain foundational concepts such as freedom of access, state responsibility and liability, non-weaponization of space, the treatment of astronauts in distress, and the prohibition of non-appropriation of

  4. Bcl-xL knockout attenuates mitochondrial respiration and causes oxidative stress that is compensated by pentose phosphate pathway activity

    NARCIS (Netherlands)

    Pfeiffer, Annika; Schneider, Julia; Bueno, Diones; Dolga, Amalia; Voss, Timo-Daniel; Lewerenz, Jan; Wüllner, Verena; Methner, Axel

    2017-01-01

    Bcl-xL is an anti-apoptotic protein that localizes to the outer mitochondrial membrane and influences mitochondrial bioenergetics by controlling Ca2+ influx into mitochondria. Here, we analyzed the effect of mitochondrial Bcl-xL on mitochondrial shape and function in knockout (KO), wild type and

  5. Atorvastatin affects negatively respiratory function of isolated endothelial mitochondria.

    Science.gov (United States)

    Broniarek, Izabela; Jarmuszkiewicz, Wieslawa

    2018-01-01

    The purpose of this research was to elucidate the direct effects of two popular blood cholesterol-lowering drugs used to treat cardiovascular diseases, atorvastatin and pravastatin, on respiratory function, membrane potential, and reactive oxygen species formation in mitochondria isolated from human umbilical vein endothelial cells (EA.hy926 cell line). Hydrophilic pravastatin did not significantly affect endothelial mitochondria function. In contrast, hydrophobic calcium-containing atorvastatin induced a loss of outer mitochondrial membrane integrity, an increase in hydrogen peroxide formation, and reductions in maximal (phosphorylating or uncoupled) respiratory rate, membrane potential and oxidative phosphorylation efficiency. The atorvastatin-induced changes indicate an impairment of mitochondrial function at the level of ATP synthesis and at the level of the respiratory chain, likely at complex I and complex III. The atorvastatin action on endothelial mitochondria was highly dependent on calcium ions and led to a disturbance in mitochondrial calcium homeostasis. Uptake of calcium ions included in atorvastatin molecule induced mitochondrial uncoupling that enhanced the inhibition of the mitochondrial respiratory chain by atorvastatin. Our results indicate that hydrophobic calcium-containing atorvastatin, widely used as anti-atherosclerotic agent, has a direct negative action on isolated endothelial mitochondria. Copyright © 2017. Published by Elsevier Inc.

  6. Mitochondrial cardiomyopathies

    Directory of Open Access Journals (Sweden)

    Ayman W. El-Hattab

    2016-07-01

    Full Text Available Mitochondria are found in all nucleated human cells and perform a variety of essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA while more than 99% of them are encoded by nuclear DNA (nDNA. Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs of various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20-40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular noncompaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain (ETC complexes subunits and their assembly factors, mitochondrial tRNAs, rRNAs, ribosomal proteins, and translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia.

  7. Saturn's outer magnetosphere

    Science.gov (United States)

    Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

    1983-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  8. The potato tuber mitochondrial proteome

    DEFF Research Database (Denmark)

    Salvato, Fernanda; Havelund, Jesper Foged; Chen, Mingjie

    2014-01-01

    Mitochondria are called the powerhouses of the cell. To better understand the role of mitochondria in maintaining and regulating metabolism in storage tissues, highly purified mitochondria were isolated from dormant potato tubers (Solanum tuberosum 'Folva') and their proteome investigated. Proteins...... manner using normalized spectral counts including as many as 5-fold more "extreme" proteins (low mass, high isoelectric point, hydrophobic) than previous mitochondrial proteome studies. We estimate that this compendium of proteins represents a high coverage of the potato tuber mitochondrial proteome...

  9. Rapid isolation of microsatellite DNAs and identification of polymorphic mitochondrial DNA regions in the fish rotan (Perccottus glenii) invading European Russia

    Science.gov (United States)

    King, Timothy L.; Eackles, Michael S.; Reshetnikov, Andrey N.

    2015-01-01

    Human-mediated translocations and subsequent large-scale colonization by the invasive fish rotan (Perccottus glenii Dybowski, 1877; Perciformes, Odontobutidae), also known as Amur or Chinese sleeper, has resulted in dramatic transformations of small lentic ecosystems. However, no detailed genetic information exists on population structure, levels of effective movement, or relatedness among geographic populations of P. glenii within the European part of the range. We used massively parallel genomic DNA shotgun sequencing on the semiconductor-based Ion Torrent Personal Genome Machine (PGM) sequencing platform to identify nuclear microsatellite and mitochondrial DNA sequences in P. glenii from European Russia. Here we describe the characterization of nine nuclear microsatellite loci, ascertain levels of allelic diversity, heterozygosity, and demographic status of P. glenii collected from Ilev, Russia, one of several initial introduction points in European Russia. In addition, we mapped sequence reads to the complete P. glenii mitochondrial DNA sequence to identify polymorphic regions. Nuclear microsatellite markers developed for P. glenii yielded sufficient genetic diversity to: (1) produce unique multilocus genotypes; (2) elucidate structure among geographic populations; and (3) provide unique perspectives for analysis of population sizes and historical demographics. Among 4.9 million filtered P. glenii Ion Torrent PGM sequence reads, 11,304 mapped to the mitochondrial genome (NC_020350). This resulted in 100 % coverage of this genome to a mean coverage depth of 102X. A total of 130 variable sites were observed between the publicly available genome from China and the studied composite mitochondrial genome. Among these, 82 were diagnostic and monomorphic between the mitochondrial genomes and distributed among 15 genome regions. The polymorphic sites (N = 48) were distributed among 11 mitochondrial genome regions. Our results also indicate that sequence reads generated

  10. Mitochondrial Myopathies

    Science.gov (United States)

    ... noting “soft signs” in unaffected relatives. These include deaf- ness, short stature, migraine headaches and PEO. Muscle ... mitochondrial defects and provide valuable information for family planning. Perhaps most important, knowing the genetic defects that ...

  11. Cigarette smoke decreases mitochondrial porin expression and steroidogenesis

    International Nuclear Information System (INIS)

    Bose, Mahuya; Whittal, Randy M.; Gairola, C. Gary; Bose, Himangshu S.

    2008-01-01

    Steroidogenic acute regulatory protein (StAR) facilitates the movement of cholesterol from the outer to inner mitochondrial membrane for steroidogenesis. Here, we investigated the effect of cigarette smoke (CS) on steroidogenesis using adrenal mitochondria isolated from mice chronically exposed to CS. Steroidogenesis was decreased approximately 78% in CS-exposed mitochondria, as measured by synthesis of the steroid hormone precursor pregnenolone. This effect was accompanied by decreased mitochondrial import of 35 S-StAR. Further characterization of the imported 35 S-StAR by native gradient PAGE revealed the presence of a high molecular weight complex in both control and CS-exposed groups. Following density gradient fractionation of 35 S-StAR that had been extracted from control mitochondria, precursor StAR could be found in fractions 2-6 and smaller-sized StAR complexes in fractions 6-13. In the CS-exposed group, the appearance of precursor shifted from fraction 1-6 and the smaller complexes in fractions 6-9 disappeared. Mass spectrometric analysis revealed that the 35 S-StAR-associated protein complex was composed of several resident matrix proteins as well as the OMM resident, VDAC. VDAC expression was greatly reduced by CS, and blockage of VDAC with Koenig's polyanion decreased pregnenolone synthesis in isolated mitochondria. Taken together, these results suggest that VDAC may participate in steroidogenesis by promoting StAR interaction with the OMM and that CS may inhibit steroidogenesis by reducing VDAC-StAR interactions

  12. TPS for Outer Planets

    Science.gov (United States)

    Venkatapathy, Ethiraj; Ellerby, D.; Gage, P.; Gasch, M.; Hwang, H.; Prabhu, D.; Stackpoole, M.; Wercinski, Paul

    2018-01-01

    This invited talk will provide an assessment of the TPS needs for Outer Planet In-situ missions to destinations with atmosphere. The talk will outline the drivers for TPS from destination, science, mission architecture and entry environment. An assessment of the readiness of the TPS, both currently available and under development, for Saturn, Titan, Uranus and Neptune are provided. The challenges related to sustainability of the TPS for future missions are discussed.

  13. Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics

    Science.gov (United States)

    Tan, Dun-Xian; Manchester, Lucien C.; Qin, Lilan; Reiter, Russel J.

    2016-01-01

    Melatonin has been speculated to be mainly synthesized by mitochondria. This speculation is supported by the recent discovery that aralkylamine N-acetyltransferase/serotonin N-acetyltransferase (AANAT/SNAT) is localized in mitochondria of oocytes and the isolated mitochondria generate melatonin. We have also speculated that melatonin is a mitochondria-targeted antioxidant. It accumulates in mitochondria with high concentration against a concentration gradient. This is probably achieved by an active transportation via mitochondrial melatonin transporter(s). Melatonin protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting the mitochondrial permeability transition pore (MPTP), and activating uncoupling proteins (UCPs). Thus, melatonin maintains the optimal mitochondrial membrane potential and preserves mitochondrial functions. In addition, mitochondrial biogenesis and dynamics is also regulated by melatonin. In most cases, melatonin reduces mitochondrial fission and elevates their fusion. Mitochondrial dynamics exhibit an oscillatory pattern which matches the melatonin circadian secretory rhythm in pinealeocytes and probably in other cells. Recently, melatonin has been found to promote mitophagy and improve homeostasis of mitochondria. PMID:27999288

  14. Intraradical Dynamics of Two Coexisting Isolates of the Arbuscular Mycorrhizal Fungus Glomus intraradices Sensu Lato as Estimated by Real-Time PCR of Mitochondrial DNA

    Czech Academy of Sciences Publication Activity Database

    Krak, Karol; Janoušková, Martina; Caklová, Petra; Vosátka, Miroslav; Štorchová, Helena

    2012-01-01

    Roč. 78, č. 10 (2012), s. 3630-3637 ISSN 0099-2240 R&D Projects: GA ČR GA526/09/0838 Institutional support: RVO:67985939 ; RVO:61389030 Keywords : real-time PCR * mitochondrial DNA * coexistence Subject RIV: EF - Botanics; EF - Botanics (UEB-Q) Impact factor: 3.678, year: 2012

  15. Ion selectivity of the cation transport system of isolated intact cattle rod outer segments: evidence for a direct communication between the rod plasma membrane and the rod disk membranes.

    Science.gov (United States)

    Schnetkamp, P P

    1980-05-08

    The ion selectivity of cation transport through the plasma membrane of isolated intact cattle rod outer segments (rods) is investigated by means of 45Ca-exchange experiments and light-scattering experiments. These techniques appear to provide complementary information: the 45Ca experiments (45Ca fluxes in rods) describe electroneutral antiport, whereas the light-scattering experiments (shrinkage and swelling of rods upon hypertonic shocks with various electrolytes) reveal electrogenic uniport. Electroneutral symport of ions (salt transport) does not take place without addition of external ionophores and application of salts of weak acids. 1. Intact rods recover from a hypertonic shock in the presence of FCCP when lithium, sodium and potassium acetate are applied, but not when ammonium chloride, calcium and magnesium acetate are used. This indicates that the plasma membrane of isolated intact cattle rods is relatively permeable to net transport of Na+, Li+ and K+, and relatively impermeable to net transport of Cl-, Mg2+ and Ca2+ under conditions that do not give rise to diffusion potentials. 2. Rapid (t1/2 exchange diffusion of internal 45Ca with external Na+, Ca2+, Sr2+ and Ba2+, respectively. 3. All tested cations lower the rate of 45Ca uptake. The latter can be described by a single rate constant indicating a homogeneous rod preparation and a homogeneous endogenous Ca2+ pool. However, only those cations which stimulate 45Ca efflux from preloaded rods lower the final equilibrium of 45Ca uptake. Except for the effects of K+, Rb+ and Cs+ the reduction of the rate of 45Ca uptake by external cations appears to arise from competition for a common site on the plasms membrane. The observed affinities for this site do not correlate with actual transport (as indicated by the ability to stimulate 45Ca efflux). 4. K+ increases the affinity of the exchange diffusion system to Ca2+ from 1 microM to 0.15 microM and changes the relative affinities with respect to Ca2+ for the

  16. Outer Continental Shelf Lands Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data represents geographic terms used within the Outer Continental Shelf Lands Act (OCSLA or Act). The Act defines the United States outer continental shelf...

  17. Management of outer space

    Science.gov (United States)

    Perek, Lubos

    1993-10-01

    Various aspects of space-environment management are discussed. Attention is called to the fact that, while space radio communications are already under an adequate management by the International Communications Union, the use of nuclear power sources is regulated by the recently adopted set of principles, and space debris will be discussed in the near future at the UN COPUOS, other aspects of management of outer space received little or no attention of the international community. These include the competency of crews and technical equipment of spacecraft launched by newcomers to space exploration; monitoring of locations and motions of space objects (now in national hands), with relevant data made accessible through a computer network; and the requirement to use space only for beneficial purposes and not for promoting narrow and debatable interests damaging the outer space environment and impeding on astronomical observations. It is suggested that some of these tasks would be best performed by an international space agency within the UN system of organizations.

  18. Mitochondrial Fusion Proteins and Human Diseases

    Directory of Open Access Journals (Sweden)

    Michela Ranieri

    2013-01-01

    Full Text Available Mitochondria are highly dynamic, complex organelles that continuously alter their shape, ranging between two opposite processes, fission and fusion, in response to several stimuli and the metabolic demands of the cell. Alterations in mitochondrial dynamics due to mutations in proteins involved in the fusion-fission machinery represent an important pathogenic mechanism of human diseases. The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1 and 2 (MFN2, located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1, in the inner membrane. An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. While these disorders can still be considered rare, defective mitochondrial dynamics seem to play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, for example, Alzheimer’s and Parkinson’s diseases. This review provides an overview of the basic molecular mechanisms involved in mitochondrial fusion and focuses on the alteration in mitochondrial DNA amount resulting from impairment of mitochondrial dynamics. We also review the literature describing the main disorders associated with the disruption of mitochondrial fusion.

  19. Mitofilin complexes: conserved organizers of mitochondrial membrane architecture.

    Science.gov (United States)

    Zerbes, Ralf M; van der Klei, Ida J; Veenhuis, Marten; Pfanner, Nikolaus; van der Laan, Martin; Bohnert, Maria

    2012-11-01

    Mitofilin proteins are crucial organizers of mitochondrial architecture. They are located in the inner mitochondrial membrane and interact with several protein complexes of the outer membrane, thereby generating contact sites between the two membrane systems of mitochondria. Within the inner membrane, mitofilins are part of hetero-oligomeric protein complexes that have been termed the mitochondrial inner membrane organizing system (MINOS). MINOS integrity is required for the maintenance of the characteristic morphology of the inner mitochondrial membrane, with an inner boundary region closely apposed to the outer membrane and cristae membranes, which form large tubular invaginations that protrude into the mitochondrial matrix and harbor the enzyme complexes of the oxidative phosphorylation machinery. MINOS deficiency comes along with a loss of crista junction structures and the detachment of cristae from the inner boundary membrane. MINOS has been conserved in evolution from unicellular eukaryotes to humans, where alterations of MINOS subunits are associated with multiple pathological conditions.

  20. Nucleotide sequence preservation of human mitochondrial DNA

    International Nuclear Information System (INIS)

    Monnat, R.J. Jr.; Loeb, L.A.

    1985-01-01

    Recombinant DNA techniques have been used to quantitate the amount of nucleotide sequence divergence in the mitochondrial DNA population of individual normal humans. Mitochondrial DNA was isolated from the peripheral blood lymphocytes of five normal humans and cloned in M13 mp11; 49 kilobases of nucleotide sequence information was obtained from 248 independently isolated clones from the five normal donors. Both between- and within-individual differences were identified. Between-individual differences were identified in approximately = to 1/200 nucleotides. In contrast, only one within-individual difference was identified in 49 kilobases of nucleotide sequence information. This high degree of mitochondrial nucleotide sequence homogeneity in human somatic cells is in marked contrast to the rapid evolutionary divergence of human mitochondrial DNA and suggests the existence of mechanisms for the concerted preservation of mammalian mitochondrial DNA sequences in single organisms

  1. Stable Transmission of Borrelia burgdorferi Sensu Stricto on the Outer Banks of North Carolina.

    Science.gov (United States)

    Levine, J F; Apperson, C S; Levin, M; Kelly, T R; Kakumanu, M L; Ponnusamy, L; Sutton, H; Salger, S A; Caldwell, J M; Szempruch, A J

    2017-08-01

    The spirochaete (Borrelia burgdorferi) associated with Lyme disease was detected in questing ticks and rodents during a period of 18 years, 1991-2009, at five locations on the Outer Banks of North Carolina. The black-legged tick (Ixodes scapularis) was collected at varied intervals between 1991 and 2009 and examined for B. burgdorferi. The white-footed mouse (Peromyscus leucopus), house mouse (Mus musculus) marsh rice rat (Oryzomys palustris), marsh rabbit (Sylvilagus palustris), eastern cottontail (Sylvilagus floridanus) and six-lined racerunner (Cnemidophorus sexlineatus) were live-trapped, and their tissues cultured to isolate spirochaetes. Borrelia burgdorferi isolates were obtained from questing adult I. scapularis and engorged I. scapularis removed from P. leucopus, O. palustris and S. floridanus. The prevalence of B. burgdorferi infection was variable at different times and sites ranging from 7 to 14% of examined questing I. scapularis. Mitochondrial (16S) rRNA gene phylogenetic analysis from 65 adult I. scapularis identified 12 haplotypes in two major clades. Nine haplotypes were associated with northern/Midwestern I. scapularis populations and three with southern I. scapularis populations. Sixteen isolates obtained from tick hosts in 2005 were confirmed to be B. burgdorferi by amplifying and sequencing of 16S rRNA and 5S-23S intergenic spacer fragments. The sequences had 98-99% identity to B. burgdorferi sensu stricto strains B31, JD1 and M11p. Taken together, these studies indicate that B. burgdorferi sensu stricto is endemic in questing I. scapularis and mammalian tick hosts on the Outer Banks of North Carolina. © 2016 Blackwell Verlag GmbH.

  2. Outer atmospheric research

    International Nuclear Information System (INIS)

    Anderson, J.L.

    1988-01-01

    The region above the earth from about 90 km to 150 km is a major part of the upper or outer atmosphere. It is relatively unexplored, being too high for balloons or aircraft and too low for persistent orbiting spacecraft. However, the concept of a tethered subsatellite, deployed downward from an orbiting, more massive craft such as the Space Shuttle, opens the possibility of a research capability that could provide global mapping of this region. The need for research in this thick spherical shell above the earth falls into two major categories: (1) scientific data for understanding and modeling the global atmosphere and thereby determining its role in the earth system, and (2) engineering data for the design of future aerospace vehicles that will operate there. This paper presents an overview and synthesis of the currently perceived research needs and the state-of-the-art of the proposed tethered research capability. 16 references

  3. Regulation of mitochondrial respiration by inorganic phosphate; comparing permeabilized muscle fibers and isolated mitochondria prepared from type-1 and type-2 rat skeletal muscle

    DEFF Research Database (Denmark)

    Scheibye-Knudsen, Morten; Quistorff, Bjørn

    2008-01-01

    ADP is generally accepted as a key regulator of oxygen consumption both in isolated mitochondria and in permeabilized fibers from skeletal muscle. The present study explored inorganic phosphate in a similar regulatory role. Saponin permeabilized fibers and isolated mitochondria from type-I and type...

  4. Selective imipenem resistance in Pseudomonas aeruginosa associated with diminished outer membrane permeability.

    OpenAIRE

    Studemeister, A E; Quinn, J P

    1988-01-01

    The permeability of the outer membranes of imipenem-susceptible and imipenem-resistant clinical isolates of Pseudomonas aeruginosa was investigated by the liposome swelling assay. Sugars and cephaloridine penetrated rapidly, whereas imipenem penetrated poorly into liposomes constructed from porin-rich outer membrane fractions of the resistant isolates.

  5. Vacuum Outer-Gap Structure in Pulsar Outer Magnetospheres

    International Nuclear Information System (INIS)

    Gui-Fang, Lin; Li, Zhang

    2009-01-01

    We study the vacuum outer-gap structure in the outer magnetosphere of rotation-powered pulsars by considering the limit of trans-field height through a pair production process. In this case, the trans-field height is limited by the photon-photon pair production process and the outer boundary of the outer gap can be extended outside the light cylinder. By solving self-consistently the Poisson equation for electrical potential and the Boltzmann equations of electrons/positrons and γ-rays in a vacuum outer gap for the parameters of Vela pulsar, we obtain an approximate geometry of the outer gap, i.e. the trans-field height is limited by the pair-production process and increases with the radial distance to the star and the width of the outer gap starts at the inner boundary (near the null charge surface) and ends at the outer boundary which locates inside or outside the light cylinder depending on the inclination angle. (geophysics, astronomy, and astrophysics)

  6. What Is Mitochondrial DNA?

    Science.gov (United States)

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  7. Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis Propriedades adesivas de uma estrutura externa de Clostridium perfringens tipo A isolada de leitões com enterite catarral

    Directory of Open Access Journals (Sweden)

    Elizabeth Pelosi Teixeira

    1999-07-01

    Full Text Available One strain (S32 of Clostridium perfringens type A was isolated from a case of catarrhal enteritis of piglets. This strain was able to adhere to HeLa cells showing an adherence index (AI of 25.15 ± 1.26 (mean ± 1 standard error of the mean. Treatment of the bacterial cells with trypsin (0.25mg/ml decreased in 70%-80% the AI and metaperiodate (10mg/ml abolished completely the adherence, suggesting that the structure responsible for this phenomenon was probably a glycoprotein. Heating of bacterial suspensions (100ºC/5 min before carrying out the adhesion test decreased the AI rendering it equal to the negative controls. Rabbit homologous S32 antiserum inhibited the adherence up to dilutions of 1: 640, at least. The piglet ileal loop assay, carried out with strains S32 and Jab-1 (negative control demonstrated that the strain S32 was able to adhere to the intestinal epithelial cells when examined after Gram staining. Transmission electron microcopy (TEM demonstrated that S32 strain displayed a loose fibrillar material not seen with Jab-1. Stabilization of the bacterial cells with homologous antiserum of strain S32, followed by staining with rhuteniun red, revealed loose long fibrillar material on the outer surface of the cells, that sometimes could be seen spreading out from the cells and linking bacterial cells. The question whether this structure might be an adhesin for this strain of Cl. perfringes type A, perhaps playing a role in the pathogenesis of the catarrhal enteritis of piglets, is dependent on further studies.Uma amostra (S32 de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitões. Esta amostra foi capaz de aderir a células HeLa mostrando um índice de adesão (AI de 25,15 ± 1,26 (media ± 1 erro padrão da media. Tratamento das células bacterianas com tripsina (0,25mg/ml diminuiu 70%-80% e metaperiodato (10mg/ml aboliu significantemente a adesão, sugerindo que a estrutura responsável por esta

  8. Evidence for high genetic diversity of NAD1 and COX1 mitochondrial haplotypes among triclabendazole resistant and susceptible populations and field isolates of Fasciola hepatica (liver fluke) in Australia.

    Science.gov (United States)

    Elliott, T; Muller, A; Brockwell, Y; Murphy, N; Grillo, V; Toet, H M; Anderson, G; Sangster, N; Spithill, T W

    2014-02-24

    In recent years, the global incidence of Fasciola hepatica (liver fluke) infections exhibiting resistance to triclabendazole (TCBZ) has increased, resulting in increased economic losses for livestock producers and threatening future control. The development of TCBZ resistance and the worldwide discovery of F. hepatica population diversity has emphasized the need to further understand the genetic structure of drug susceptible and resistant Fasciola populations within Australia. In this study, the genetic diversity of liver flukes was estimated by sequencing mitochondrial DNA (mtDNA) encoding the NAD1 (530 bp) and COX1 (420 bp) genes of 208 liver flukes (F. hepatica) collected from three populations: field isolates obtained from abattoirs from New South Wales (NSW) and Victoria (Vic); three TCBZ-resistant fluke populations from NSW and Victoria; and the well-established TCBZ-susceptible Sunny Corner laboratory isolate. Overall nucleotide diversity for all flukes analysed of 0.00516 and 0.00336 was estimated for the NAD1 and COX1 genes respectively. Eighteen distinct haplotypes were established for the NAD1 gene and six haplotypes for the COX1 gene, resulting in haplotype diversity levels of 0.832 and 0.482, respectively. One field isolate showed a similar low level of haplotype diversity as seen in the Sunny Corner laboratory isolate. Analysis of TCBZ-resistant infrapopulations from 3 individual cattle grazing one property revealed considerable sequence parasite diversity between cattle. Analysis of parasite TCBZ-resistant infrapopulations from sheep and cattle revealed haplotypes unique to each host, but no significant difference between parasite populations. Fst analysis of fluke populations revealed little differentiation between the resistant and field populations. This study has revealed a high level of diversity in field and drug resistant flukes in South-Eastern Australia. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Properties of the mitochondrial carrier of adenine-nucleotide after purification. Study of the transport protein under isolated form and reincorporated form in phospho-lipidic vesicles

    International Nuclear Information System (INIS)

    Brandolin, Gerard

    1983-01-01

    The first part of this research thesis addresses the reconstitution of the ADP/ATP transport by incorporation of the specific carrier, isolated in presence of detergent, in phospholipids vesicles. Fundamental properties of the reconstituted transport are identical to that of transport in mitochondria, notably as far as the exchange stoichiometry, the turn over and the transport Km are concerned, as well as the asymmetric orientation of the carrier in the membrane. The second part of this research addresses the study of interactions of specific ligands with the ADP/ATP transport protein in presence of detergent. The study of the variations of the intrinsic fluorescence of the isolated ADP/ATP carrier highlights conformational changes exclusively induced by the presence of transportable nucleotides which are modulated in a different manner by carboxy-atractyloside or bongkrekic acid. Moreover, by using the isolated protein, a detailed analysis of binding parameters of fluorescent analogues of ATP is reported [fr

  10. A mitochondrial cytochrome b mutation causing severe respiratory chain enzyme deficiency in humans and yeast.

    NARCIS (Netherlands)

    Blakely, E.L.; Mitchell, A.L.; Fisher, N.; Meunier, B.; Nijtmans, L.G.J.; Schaefer, A.M.; Jackson, M.J.; Turnbull, D.M.; Taylor, R.W.

    2005-01-01

    Whereas the majority of disease-related mitochondrial DNA mutations exhibit significant biochemical and clinical heterogeneity, mutations within the mitochondrially encoded human cytochrome b gene (MTCYB) are almost exclusively associated with isolated complex III deficiency in muscle and a clinical

  11. Outer membrane protein functions as integrator of protein import and DNA inheritance in mitochondria

    Science.gov (United States)

    Käser, Sandro; Oeljeklaus, Silke; Týč, Jiří; Vaughan, Sue; Warscheid, Bettina; Schneider, André

    2016-01-01

    Trypanosomatids are one of the earliest diverging eukaryotes that have fully functional mitochondria. pATOM36 is a trypanosomatid-specific essential mitochondrial outer membrane protein that has been implicated in protein import. Changes in the mitochondrial proteome induced by ablation of pATOM36 and in vitro assays show that pATOM36 is required for the assembly of the archaic translocase of the outer membrane (ATOM), the functional analog of the TOM complex in other organisms. Reciprocal pull-down experiments and immunofluorescence analyses demonstrate that a fraction of pATOM36 interacts and colocalizes with TAC65, a previously uncharacterized essential component of the tripartite attachment complex (TAC). The TAC links the single-unit mitochondrial genome to the basal body of the flagellum and mediates the segregation of the replicated mitochondrial genomes. RNAi experiments show that pATOM36, in line with its dual localization, is not only essential for ATOM complex assembly but also for segregation of the replicated mitochondrial genomes. However, the two functions are distinct, as a truncated version of pATOM36 lacking the 75 C-terminal amino acids can rescue kinetoplast DNA missegregation but not the lack of ATOM complex assembly. Thus, pATOM36 has a dual function and integrates mitochondrial protein import with mitochondrial DNA inheritance. PMID:27436903

  12. Protosappanin B protects PC12 cells against oxygen-glucose deprivation-induced neuronal death by maintaining mitochondrial homeostasis via induction of ubiquitin-dependent p53 protein degradation.

    Science.gov (United States)

    Zeng, Ke-Wu; Liao, Li-Xi; Zhao, Ming-Bo; Song, Fang-Jiao; Yu, Qian; Jiang, Yong; Tu, Peng-Fei

    2015-03-15

    Protosappanin B (PTB) is a bioactive dibenzoxocin derivative isolated from Caesalpinia sappan L. Here, we investigated the neuroprotective effects and the potential mechanisms of PTB on oxygen-glucose deprivation (OGD)-injured PC12 cells. Results showed that PTB significantly increased cell viability, inhibited cell apoptosis and up-regulated the expression of growth-associated protein 43 (a marker of neural outgrowth). Moreover, our study revealed that PTB effectively maintained mitochondrial homeostasis by up-regulation of mitochondrial membrane potential (MMP), inhibition of cytochrome c release from mitochondria and inactivation of mitochondrial caspase-9/3 apoptosis pathway. Further study showed that PTB significantly promoted cytoplasmic component degradation of p53 protein, a key negative regulator for mitochondrial function, resulting in a release of Bcl-2 from p53-Bcl-2 complex and an enhancing translocation of Bcl-2 to mitochondrial outer membrane. Finally, we found the degradation of p53 protein was induced by PTB via activation of a MDM2-dependent ubiquitination process. Taken together, our findings provided a new viewpoint of neuronal protection strategy for anoxia and ischemic injury with natural small molecular dibenzoxocin derivative by activating ubiquitin-dependent p53 protein degradation as well as increasing mitochondrial function. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The mitochondrial genome of Paragonimus westermani (Kerbert, 1878, the Indian isolate of the lung fluke representative of the family Paragonimidae (Trematoda

    Directory of Open Access Journals (Sweden)

    Devendra K. Biswal

    2014-08-01

    Full Text Available Among helminth parasites, Paragonimus (zoonotic lung fluke gains considerable importance from veterinary and medical points of view because of its diversified effect on its host. Nearly fifty species of Paragonimus have been described across the globe. It is estimated that more than 20 million people are infected worldwide and the best known species is Paragonimus westermani, whose type locality is probably India and which infects millions of people in Asia causing disease symptoms that mimic tuberculosis. Human infections occur through eating raw crustaceans containing metacercarie or ingestion of uncooked meat of paratenic hosts such as pigs. Though the fluke is known to parasitize a wide range of mammalian hosts representing as many as eleven families, the status of its prevalence, host range, pathogenic manifestations and its possible survivors in nature from where the human beings contract the infection is not well documented in India. We took advantage of the whole genome sequence data for P. westermani, generated by Next Generation Sequencing, and its comparison with the existing data for the P. westermani for comparative mt DNA phylogenomic analyses. Specific primers were designed for the 12 protein coding genes with the aid of existing P. westermani mtDNA as the reference. The Ion torrent next generation sequencing platform was harnessed to completely sequence the mitochondrial genome, and applied innovative approaches to bioinformatically assemble and annotate it. A strategic PCR primer design utilizing the whole genome sequence data from P. westermani enabled us to design specific primers capable of amplifying all regions of the mitochondrial genome from P. westermani. Assembly of NGS data from libraries enriched in mtDNA sequence by PCR gave rise to a total of 11 contigs spanning the entire 14.7 kb mt DNA sequence of P. westermani available at NCBI. We conducted gap-filling by traditional Sanger sequencing to fill in the gaps

  14. Acute Zonal Cone Photoreceptor Outer Segment Loss.

    Science.gov (United States)

    Aleman, Tomas S; Sandhu, Harpal S; Serrano, Leona W; Traband, Anastasia; Lau, Marisa K; Adamus, Grazyna; Avery, Robert A

    2017-05-01

    The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if

  15. Turbine airfoil with outer wall thickness indicators

    Science.gov (United States)

    Marra, John J; James, Allister W; Merrill, Gary B

    2013-08-06

    A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

  16. Mitochondrial benzodiazepine receptors regulate steroid biosynthesis.

    OpenAIRE

    Mukhin, A G; Papadopoulos, V; Costa, E; Krueger, K E

    1989-01-01

    Recent observations on the steroid synthetic capability within the brain open the possibility that benzodiazepines may influence steroid synthesis in nervous tissue through interactions with peripheral-type benzodiazepine recognition sites, which are highly expressed in steroidogenic cells and associated with the outer mitochondrial membrane. To examine this possibility nine molecules that exhibit a greater than 10,000-fold difference in their affinities for peripheral-type benzodiazepine bin...

  17. Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H

    DEFF Research Database (Denmark)

    Larsen, Steen; Díez-Sánchez, Carmen; Rabøl, Rasmus

    2014-01-01

    and determined their mitochondrial haplogroup, mitochondrial oxidative phosphorylation capacity (OXPHOS), mitochondrial content (citrate synthase (CS)) and VO2max. Intrinsic mitochondrial function is calculated as mitochondrial OXPHOS capacity divided by mitochondrial content (CS). Haplogroup H showed a 30......% higher intrinsic mitochondrial function compared with the other haplo group U. There was no relationship between haplogroups and VO2max. In skeletal muscle from men with mitochondrial haplogroup H, an increased intrinsic mitochondrial function is present....

  18. Long-term tracing of Rhizophagus irregularis isolate BEG140 inoculated on Phalaris arundinacea in a coal mine spoil bank, using mitochondrial large subunit rDNA markers

    Czech Academy of Sciences Publication Activity Database

    Sýkorová, Zuzana; Börstler, B.; Zvolenská, Soňa; Fehrer, Judith; Gryndler, Milan; Vosátka, Miroslav; Redecker, D.

    2012-01-01

    Roč. 22, č. 1 (2012), s. 69-80 ISSN 0940-6360 R&D Projects: GA MŠk 1M0571; GA ČR GPP504/10/P021 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50200510 Keywords : Rhizophagus irregularis * inoculation * isolate tracing Subject RIV: EF - Botanics Impact factor: 2.955, year: 2012

  19. Mitochondrial Respiration and Oxygen Tension.

    Science.gov (United States)

    Shaw, Daniel S; Meitha, Karlia; Considine, Michael J; Foyer, Christine H

    2017-01-01

    Measurements of respiration and oxygen tension in plant organs allow a precise understanding of mitochondrial capacity and function within the context of cellular oxygen metabolism. Here we describe methods that can be routinely used for the isolation of intact mitochondria, and the determination of respiratory electron transport, together with techniques for in vivo determination of oxygen tension and measurement of respiration by both CO 2 production and O 2 consumption that enables calculation of the respiratory quotient [CO 2 ]/[O 2 ].

  20. Mitochondrial Protein Synthesis, Import, and Assembly

    Science.gov (United States)

    Fox, Thomas D.

    2012-01-01

    The mitochondrion is arguably the most complex organelle in the budding yeast cell cytoplasm. It is essential for viability as well as respiratory growth. Its innermost aqueous compartment, the matrix, is bounded by the highly structured inner membrane, which in turn is bounded by the intermembrane space and the outer membrane. Approximately 1000 proteins are present in these organelles, of which eight major constituents are coded and synthesized in the matrix. The import of mitochondrial proteins synthesized in the cytoplasm, and their direction to the correct soluble compartments, correct membranes, and correct membrane surfaces/topologies, involves multiple pathways and macromolecular machines. The targeting of some, but not all, cytoplasmically synthesized mitochondrial proteins begins with translation of messenger RNAs localized to the organelle. Most proteins then pass through the translocase of the outer membrane to the intermembrane space, where divergent pathways sort them to the outer membrane, inner membrane, and matrix or trap them in the intermembrane space. Roughly 25% of mitochondrial proteins participate in maintenance or expression of the organellar genome at the inner surface of the inner membrane, providing 7 membrane proteins whose synthesis nucleates the assembly of three respiratory complexes. PMID:23212899

  1. BID is cleaved by caspase-8 within a native complex on the mitochondrial membrane

    NARCIS (Netherlands)

    Schug, Z. T.; Gonzalvez, F.; Houtkooper, R. H.; Vaz, F. M.; Gottlieb, E.

    2011-01-01

    Caspase-8 stably inserts into the mitochondrial outer membrane during extrinsic apoptosis. Inhibition of caspase-8 enrichment on the mitochondria impairs caspase-8 activation and prevents apoptosis. However, the function of active caspase-8 on the mitochondrial membrane remains unknown. In this

  2. Altered Mitochondrial Dynamics and TBI Pathophysiology

    Directory of Open Access Journals (Sweden)

    Tara Diane Fischer

    2016-03-01

    Full Text Available Mitochondrial function is intimately linked to cellular survival, growth, and death. Mitochondria not only generate ATP from oxidative phosphorylation, but also mediate intracellular calcium buffering, generation of reactive oxygen species (ROS, and apoptosis. Electron leakage from the electron transport chain, especially from damaged or depolarized mitochondria, can generate excess free radicals that damage cellular proteins, DNA, and lipids. Furthermore, mitochondrial damage releases pro-apoptotic factors to initiate cell death. Previous studies have reported that traumatic brain injury (TBI reduces mitochondrial respiration, enhances production of ROS, and triggers apoptotic cell death, suggesting a prominent role of mitochondria in TBI pathophysiology. Mitochondria maintain cellular energy homeostasis and health via balanced processes of fusion and fission, continuously dividing and fusing to form an interconnected network throughout the cell. An imbalance of these processes, particularly an excess of fission, can be detrimental to mitochondrial function, causing decreased respiration, ROS production, and apoptosis. Mitochondrial fission is regulated by the cytosolic GTPase, dynamin-related protein 1 (Drp1, which translocates to the mitochondrial outer membrane to initiate fission. Aberrant Drp1 activity has been linked to excessive mitochondrial fission and neurodegeneration. Measurement of Drp1 levels in purified hippocampal mitochondria showed an increase in TBI animals as compared to sham controls. Analysis of cryo-electron micrographs of these mitochondria also showed that TBI caused an initial increase in the length of hippocampal mitochondria at 24 hours post-injury, followed by a significant decrease in length at 72 hours. Post-TBI administration of Mdivi-1, a pharmacological inhibitor of Drp1, prevented this decrease in mitochondria length. Mdivi-1 treatment also reduced the loss of newborn neurons in the hippocampus and improved

  3. Reduction of brain mitochondrial β-oxidation impairs complex I and V in chronic alcohol intake: the underlying mechanism for neurodegeneration.

    Directory of Open Access Journals (Sweden)

    James Haorah

    Full Text Available Neuropathy and neurocognitive deficits are common among chronic alcohol users, which are believed to be associated with mitochondrial dysfunction in the brain. The specific type of brain mitochondrial respiratory chain complexes (mRCC that are adversely affected by alcohol abuse has not been studied. Thus, we examined the alterations of mRCC in freshly isolated mitochondria from mice brain that were pair-fed the ethanol (4% v/v and control liquid diets for 7-8 weeks. We observed that alcohol intake severely reduced the levels of complex I and V. A reduction in complex I was associated with a decrease in carnitine palmitoyltransferase 1 (cPT1 and cPT2 levels. The mitochondrial outer (cPT1 and inner (cPT2 membrane transporter enzymes are specialized in acylation of fatty acid from outer to inner membrane of mitochondria for ATP production. Thus, our results showed that alterations of cPT1 and cPT2 paralleled a decrease β-oxidation of palmitate and ATP production, suggesting that impairment of substrate entry step (complex I function can cause a negative impact on ATP production (complex V function. Disruption of cPT1/cPT2 was accompanied by an increase in cytochrome C leakage, while reduction of complex I and V paralleled a decrease in depolarization of mitochondrial membrane potential (ΔΨ, monitored by JC-1 fluorescence and ATP production in alcohol intake. We noted that acetyl-L-carnitine (ALC, a cofactor of cPT1 and cPT2 prevented the adverse effects of alcohol while coenzyme Q10 (CoQ10 was not very effective against alcohol insults. These results suggest that understanding the molecular, biochemical, and signaling mechanisms of the CNS mitochondrial β-oxidation such as ALC can mitigate alcohol related neurological disorders.

  4. Reduction of brain mitochondrial β-oxidation impairs complex I and V in chronic alcohol intake: the underlying mechanism for neurodegeneration.

    Science.gov (United States)

    Haorah, James; Rump, Travis J; Xiong, Huangui

    2013-01-01

    Neuropathy and neurocognitive deficits are common among chronic alcohol users, which are believed to be associated with mitochondrial dysfunction in the brain. The specific type of brain mitochondrial respiratory chain complexes (mRCC) that are adversely affected by alcohol abuse has not been studied. Thus, we examined the alterations of mRCC in freshly isolated mitochondria from mice brain that were pair-fed the ethanol (4% v/v) and control liquid diets for 7-8 weeks. We observed that alcohol intake severely reduced the levels of complex I and V. A reduction in complex I was associated with a decrease in carnitine palmitoyltransferase 1 (cPT1) and cPT2 levels. The mitochondrial outer (cPT1) and inner (cPT2) membrane transporter enzymes are specialized in acylation of fatty acid from outer to inner membrane of mitochondria for ATP production. Thus, our results showed that alterations of cPT1 and cPT2 paralleled a decrease β-oxidation of palmitate and ATP production, suggesting that impairment of substrate entry step (complex I function) can cause a negative impact on ATP production (complex V function). Disruption of cPT1/cPT2 was accompanied by an increase in cytochrome C leakage, while reduction of complex I and V paralleled a decrease in depolarization of mitochondrial membrane potential (ΔΨ, monitored by JC-1 fluorescence) and ATP production in alcohol intake. We noted that acetyl-L-carnitine (ALC, a cofactor of cPT1 and cPT2) prevented the adverse effects of alcohol while coenzyme Q10 (CoQ10) was not very effective against alcohol insults. These results suggest that understanding the molecular, biochemical, and signaling mechanisms of the CNS mitochondrial β-oxidation such as ALC can mitigate alcohol related neurological disorders.

  5. Role of mitochondrial ATP-sensitive potassium channel-mediated PKC-ε in delayed protection against myocardial ischemia/reperfusion injury in isolated hearts of sevoflurane-preconditioned rats

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C. [Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou (China); Institute of Neuroscience, Soochow University, Suzhou (China); Hu, S.M. [Institute of Neuroscience, Soochow University, Suzhou (China); Xie, H.; Qiao, S.G. [Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou (China); Liu, H. [Department of Anesthesiology and Pain Medicine, University of California Davis Health System, Davis, CA (United States); Liu, C.F. [Institute of Neuroscience, Soochow University, Suzhou (China)

    2015-03-27

    This study aimed to determine the role of mitochondrial adenosine triphosphate-sensitive potassium (mitoK{sub ATP}) channels and protein kinase C (PKC)-ε in the delayed protective effects of sevoflurane preconditioning using Langendorff isolated heart perfusion models. Fifty-four isolated perfused rat hearts were randomly divided into 6 groups (n=9). The rats were exposed for 60 min to 2.5% sevoflurane (the second window of protection group, SWOP group) or 33% oxygen inhalation (I/R group) 24 h before coronary occlusion. The control group (CON) and the sevoflurane group (SEVO) group were exposed to 33% oxygen and 2.5% sevoflurane for 60 min, respectively, without coronary occlusion. The mitoK{sub ATP} channel inhibitor 5-hydroxydecanoate (5-HD) was given 30 min before sevoflurane preconditioning (5-HD+SWOP group). Cardiac function indices, infarct sizes, serum cardiac troponin I (cTnI) concentrations, and the expression levels of phosphorylated PKC-ε (p-PKC-ε) and caspase-8 were measured. Cardiac function was unchanged, p-PKC-ε expression was upregulated, caspase-8 expression was downregulated, cTnI concentrations were decreased, and the infarcts were significantly smaller (P<0.05) in the SWOP group compared with the I/R group. Cardiac function was worse, p-PKC-ε expression was downregulated, caspase-8 expression was upregulated, cTnI concentration was increased and infarcts were larger in the 5-HD+SWOP group (P<0.05) compared with the SWOP group. The results suggest that mitoK{sub ATP} channels are involved in the myocardial protective effects of sevoflurane in preconditioning against I/R injury, by regulating PKC-ε phosphorylation before ischemia, and by downregulating caspase-8 during reperfusion.

  6. Efficient isolation of pure and functional mitochondria from mouse tissues using automated tissue disruption and enrichment with anti-TOM22 magnetic beads.

    Directory of Open Access Journals (Sweden)

    Andras Franko

    Full Text Available To better understand molecular mechanisms regulating changes in metabolism, as observed e.g. in diabetes or neuronal disorders, the function of mitochondria needs to be precisely determined. The usual isolation methods such as differential centrifugation result in isolates of highly variable quality and quantity. To fulfill the need of a reproducible isolation method from solid tissues, which is suitable to handle parallel samples simultaneously, we developed a protocol based on anti-TOM22 (translocase of outer mitochondrial membrane 22 homolog antibody-coupled magnetic beads. To measure oxygen consumption rate in isolated mitochondria from various mouse tissues, a traditional Clark electrode and the high-throughput XF Extracellular Flux Analyzer were used. Furthermore, Western blots, transmission electron microscopic and proteomic studies were performed to analyze the purity and integrity of the mitochondrial preparations. Mitochondrial fractions isolated from liver, brain and skeletal muscle by anti-TOM22 magnetic beads showed oxygen consumption capacities comparable to previously reported values and little contamination with other organelles. The purity and quality of isolated mitochondria using anti-TOM22 magnetic beads was compared to traditional differential centrifugation protocol in liver and the results indicated an obvious advantage of the magnetic beads method compared to the traditional differential centrifugation technique.

  7. The CMS Outer Hadron Calorimeter

    CERN Document Server

    Acharya, Bannaje Sripathi; Banerjee, Sunanda; Banerjee, Sudeshna; Bawa, Harinder Singh; Beri, Suman Bala; Bhandari, Virender; Bhatnagar, Vipin; Chendvankar, Sanjay; Deshpande, Pandurang Vishnu; Dugad, Shashikant; Ganguli, Som N; Guchait, Monoranjan; Gurtu, Atul; Kalmani, Suresh Devendrappa; Kaur, Manjit; Kohli, Jatinder Mohan; Krishnaswamy, Marthi Ramaswamy; Kumar, Arun; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mondal, Naba Kumar; Nagaraj, P; Narasimham, Vemuri Syamala; Patil, Mandakini Ravindra; Reddy, L V; Satyanarayana, B; Sharma, Seema; Singh, B; Singh, Jas Bir; Sudhakar, Katta; Tonwar, Suresh C; Verma, Piyush

    2006-01-01

    The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with a outer calorimeter to ensure high energy shower containment in CMS and thus working as a tail catcher. Fabrication, testing and calibrations of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing $\\et$ measurements at LHC energies. The outer hadron calorimeter has a very good signal to background ratio even for a minimum ionising particle and can hence be used in coincidence with the Resistive Plate Chambers of the CMS detector for the muon trigger.

  8. Origin of Outer Solar System

    Science.gov (United States)

    Holman, Matthew J.; Lindstrom, David (Technical Monitor)

    2005-01-01

    Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

  9. Nuclear fuel grid outer strap

    International Nuclear Information System (INIS)

    Duncan, R.; Craver, J.E.

    1989-01-01

    This patent describes a nuclear reactor fuel assembly grid. It comprises a first outer grip strap segment end. The first end having a first tab arranged in substantially the same plane as the plane defined by the first end; a second outer grip strap end. The second end having a second slot arranged in substantially the same plane as the plane defined by the second end, with the tab being substantially disposed in the slot, defining a socket therebetween; and a fort tine interposed substantially perpendicularly in the socket

  10. The expanding phenotype of mitochondrial myopathy.

    Science.gov (United States)

    DiMauro, Salvatore; Gurgel-Giannetti, Juliana

    2005-10-01

    Our understanding of mitochondrial diseases (defined restrictively as defects in the mitochondrial respiratory chain) continues to progress apace. In this review we provide an update of information regarding disorders that predominantly or exclusively affect skeletal muscle. Most recently described mitochondrial myopathies are due to defects in nuclear DNA, including coenzyme Q10 deficiency, and mutations in genes that control mitochondrial DNA (mtDNA) abundance and structure such as POLG and TK2. Barth syndrome, an X-linked recessive mitochondrial myopathy/cardiopathy, is associated with altered lipid composition of the inner mitochondrial membrane, but a putative secondary impairment of the respiratory chain remains to be documented. Concerning the 'other genome', the role played by mutations in protein encoding genes of mtDNA in causing isolated myopathies has been confirmed. It has also been confirmed that mutations in tRNA genes of mtDNA can cause predominantly myopathic syndromes and - contrary to conventional wisdom - these mutations can be homoplasmic. Defects in the mitochondrial respiratory chain impair energy production and almost invariably involve skeletal muscle, causing exercise intolerance, myalgia, cramps, or fixed weakness, which often affects extraocular muscles and results in droopy eyelids (ptosis) and progressive external ophthalmoplegia.

  11. Getting Sloshed in Outer Space

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Getting Sloshed in Outer Space - Liquid Behavior in Microgravity. N Ananthkrishnan. General Article Volume 12 Issue 12 December 2007 pp 40-45. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Outer space structure and development

    International Nuclear Information System (INIS)

    Zeldovich, J.; Novikov, I.

    1975-01-01

    A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses. (J.K.)

  13. Outer space structure and development

    Energy Technology Data Exchange (ETDEWEB)

    Zeldovich, J; Novikov, I

    1975-10-01

    A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses.

  14. Plasmas in the outer heliosphere

    Science.gov (United States)

    Belcher, J. W.; Richardson, J. D.; Lazarus, A. J.; Gazis, P. R.; Barnes, A.

    1995-01-01

    We review the observed properties of the solar wind in the outer heliosphere, including observations from Voyager and the Pioneers, as well as from inner heliospheric probes as appropriate. These observations are crucial to modeling of the heliosphere and its interactions with the interstellar medium, since the wind ram pressure and its temporal variations are important in understanding the distance to the termination shock and heliopause and how those boundaries might vary in time. We focus on results since Solar Wind 7. Among the issues we will discuss are: (1) the time scales for and statistical properties of variations in the ram pressure in the outer heliosphere, and how those variations might affect the morphology of the heliospheric/interstellar medium interface; (2) the question of possible solar wind slowing in the outer heliosphere due to the pick-up of interstellar ions; (3) the issue of whether there is bulk heating of the solar wind associated either with interstellar ion pick-up or with continued heating due to stream-stream interactions; (4) evidence for latitudinal variations in solar wind properties; and (5) the 1.3 year periodicities apparent in the outer heliosphere, and the close correspondence with similar variations seen with inner heliospheric probes.

  15. Outer Synchronization of Complex Networks by Impulse

    International Nuclear Information System (INIS)

    Sun Wen; Yan Zizong; Chen Shihua; Lü Jinhu

    2011-01-01

    This paper investigates outer synchronization of complex networks, especially, outer complete synchronization and outer anti-synchronization between the driving network and the response network. Employing the impulsive control method which is uncontinuous, simple, efficient, low-cost and easy to implement in practical applications, we obtain some sufficient conditions of outer complete synchronization and outer anti-synchronization between two complex networks. Numerical simulations demonstrate the effectiveness of the proposed impulsive control scheme. (general)

  16. The dynamic equilibrium between ATP synthesis and ATP consumption is lower in isolated mitochondria from myotubes established from type 2 diabetic subjects compared to lean control

    DEFF Research Database (Denmark)

    Minet, Ariane D; Gaster, Michael

    2011-01-01

    compared to lean control. The ATP synthesis rate without ATP consumption was not different between groups and there were no significant gender differences. The mitochondrial dysfunction in type 2 diabetes in vivo is partly based on a primarily impaired ATP synthesis....... or not in the mitochondria of diabetic skeletal muscle from subjects with type 2 diabetes. ATP synthesis was measured on mitochondria isolated from cultured myotubes established from lean (11/9), obese (9/11) and subjects with type 2 diabetes (9/11) (female/male, n=20 in each group), precultured under normophysiological...... selects the mitochondria based on an antibody recognizing the mitochondrial outer membrane and not by size through gradient centrifugation. The dynamic equilibrium between ATP synthesis and ATP consumption is 35% lower in isolated mitochondria from myotubes established from type 2 diabetic subjects...

  17. Mechanistic perspective of mitochondrial fusion: tubulation vs. fragmentation.

    Science.gov (United States)

    Escobar-Henriques, Mafalda; Anton, Fabian

    2013-01-01

    Mitochondrial fusion is a fundamental process driven by dynamin related GTPase proteins (DRPs), in contrast to the general SNARE-dependence of most cellular fusion events. The DRPs Mfn1/Mfn2/Fzo1 and OPA1/Mgm1 are the key effectors for fusion of the mitochondrial outer and inner membranes, respectively. In order to promote fusion, these two DRPs require post-translational modifications and proteolysis. OPA1/Mgm1 undergoes partial proteolytic processing, which results in a combination between short and long isoforms. In turn, ubiquitylation of mitofusins, after oligomerization and GTP hydrolysis, promotes and positively regulates mitochondrial fusion. In contrast, under conditions of mitochondrial dysfunction, negative regulation by proteolysis on these DRPs results in mitochondrial fragmentation. This occurs by complete processing of OPA1 and via ubiquitylation and degradation of mitofusins. Mitochondrial fragmentation contributes to the elimination of damaged mitochondria by mitophagy, and may play a protective role against Parkinson's disease. Moreover, a link of Mfn2 to Alzheimer's disease is emerging and mutations in Mfn2 or OPA1 cause Charcot-Marie-Tooth type 2A neuropathy or autosomal-dominant optic atrophy. Here, we summarize our current understanding on the molecular mechanisms promoting or inhibiting fusion of mitochondrial membranes, which is essential for cellular survival and disease control. This article is part of a Special Issue entitled: Mitochondrial dynamics and physiology. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Mitochondrial benzodiazepine receptors regulate steroid biosynthesis

    International Nuclear Information System (INIS)

    Mukhin, A.G.; Papadopoulos, V.; Costa, E.; Krueger, K.E.

    1989-01-01

    Recent observations on the steroid synthetic capability within the brain open the possibility that benzodiazepines may influence steroid synthesis in nervous tissue through interactions with peripheral-type benzodiazepine recognition sites, which are highly expressed in steroidogenic cells and associated with the outer mitochondrial membrane. To examine this possibility nine molecules that exhibit a greater than 10,000-fold difference in their affinities for peripheral-type benzodiazepine binding sites were tested for their effects on a well-established steroidogenic model system, the Y-1 mouse adrenal tumor cell line. 4'-Chlorodiazepam, PK 11195, and PK 14067 stimulated steroid production by 2-fold in Y-1 cells, whereas diazepam, flunitrazepam, zolpidem, and PK 14068 displayed a lower (1.2- to 1.5-fold) maximal stimulation. In contrast, clonazepam and flumazenil did not stimulate steroid synthesis. The potencies of these compounds to inhibit 3 H-labeled PK 11195 binding to peripheral-type benzodiazepine recognition sites correlated with their potencies to stimulate steroid production. Similar findings were observed in bovine and rat adrenocortical cell preparations. These results suggest that ligands of the peripheral-type benzodiazepine recognition site acting on this mitochondrial receptor can enhance steroid production. This action may contribute specificity to the pharmacological profile of drugs preferentially acting on the benzodiazepine recognition site associated with the outer membrane of certain mitochondrial populations

  19. Mitochondrial benzodiazepine receptors regulate steroid biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mukhin, A.G.; Papadopoulos, V.; Costa, E.; Krueger, K.E. (Georgetown Univ. School of Medicine, Washington, DC (USA))

    1989-12-01

    Recent observations on the steroid synthetic capability within the brain open the possibility that benzodiazepines may influence steroid synthesis in nervous tissue through interactions with peripheral-type benzodiazepine recognition sites, which are highly expressed in steroidogenic cells and associated with the outer mitochondrial membrane. To examine this possibility nine molecules that exhibit a greater than 10,000-fold difference in their affinities for peripheral-type benzodiazepine binding sites were tested for their effects on a well-established steroidogenic model system, the Y-1 mouse adrenal tumor cell line. 4{prime}-Chlorodiazepam, PK 11195, and PK 14067 stimulated steroid production by 2-fold in Y-1 cells, whereas diazepam, flunitrazepam, zolpidem, and PK 14068 displayed a lower (1.2- to 1.5-fold) maximal stimulation. In contrast, clonazepam and flumazenil did not stimulate steroid synthesis. The potencies of these compounds to inhibit {sup 3}H-labeled PK 11195 binding to peripheral-type benzodiazepine recognition sites correlated with their potencies to stimulate steroid production. Similar findings were observed in bovine and rat adrenocortical cell preparations. These results suggest that ligands of the peripheral-type benzodiazepine recognition site acting on this mitochondrial receptor can enhance steroid production. This action may contribute specificity to the pharmacological profile of drugs preferentially acting on the benzodiazepine recognition site associated with the outer membrane of certain mitochondrial populations.

  20. Turbine airfoil with a compliant outer wall

    Science.gov (United States)

    Campbell, Christian X [Oviedo, FL; Morrison, Jay A [Oviedo, FL

    2012-04-03

    A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation in the outer layer is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a support structure. The outer layer may be a compliant layer configured such that the outer layer may thermally expand and thereby reduce the stress within the outer layer. The outer layer may be formed from a nonplanar surface configured to thermally expand. In another embodiment, the outer layer may be planar and include a plurality of slots enabling unrestricted thermal expansion in a direction aligned with the outer layer.

  1. Mitochondrial haplogroups in patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Duhn, Pernille Hurup; Sode, Jacob; Hagen, Christian Munch

    2017-01-01

    Objective To describe the distribution of specific mitochondrial DNA (mtDNA) haplogroups (hgs) in a cohort of patients with rheumatoid arthritis (RA). Methods Two-hundred nineteen consecutive patients with RA had mtDNA isolated from their blood, sequenced and haplotyped. Patients were diagnosed...

  2. PREVENTION OF PHOSPHATE - INDUCED MITOCHONDRIAL SWELLING

    Science.gov (United States)

    Kroll, Arnold J.; Kuwabara, Toichiro

    1962-01-01

    The prevention of phosphate-induced mitochondrial swelling in the whole retina of the rabbit was studied with the electron microscope. It was found that a mixture of ATP, Mg++, and bovine serum albumin protected the mitochondria in vitro. This finding confirmed the results obtained spectrophotometrically with isolated rat liver mitochondria by Lehninger. PMID:13927020

  3. Loss of VPS13C Function in Autosomal-Recessive Parkinsonism Causes Mitochondrial Dysfunction and Increases PINK1/Parkin-Dependent Mitophagy.

    Science.gov (United States)

    Lesage, Suzanne; Drouet, Valérie; Majounie, Elisa; Deramecourt, Vincent; Jacoupy, Maxime; Nicolas, Aude; Cormier-Dequaire, Florence; Hassoun, Sidi Mohamed; Pujol, Claire; Ciura, Sorana; Erpapazoglou, Zoi; Usenko, Tatiana; Maurage, Claude-Alain; Sahbatou, Mourad; Liebau, Stefan; Ding, Jinhui; Bilgic, Basar; Emre, Murat; Erginel-Unaltuna, Nihan; Guven, Gamze; Tison, François; Tranchant, Christine; Vidailhet, Marie; Corvol, Jean-Christophe; Krack, Paul; Leutenegger, Anne-Louise; Nalls, Michael A; Hernandez, Dena G; Heutink, Peter; Gibbs, J Raphael; Hardy, John; Wood, Nicholas W; Gasser, Thomas; Durr, Alexandra; Deleuze, Jean-François; Tazir, Meriem; Destée, Alain; Lohmann, Ebba; Kabashi, Edor; Singleton, Andrew; Corti, Olga; Brice, Alexis

    2016-03-03

    Autosomal-recessive early-onset parkinsonism is clinically and genetically heterogeneous. The genetic causes of approximately 50% of autosomal-recessive early-onset forms of Parkinson disease (PD) remain to be elucidated. Homozygozity mapping and exome sequencing in 62 isolated individuals with early-onset parkinsonism and confirmed consanguinity followed by data mining in the exomes of 1,348 PD-affected individuals identified, in three isolated subjects, homozygous or compound heterozygous truncating mutations in vacuolar protein sorting 13C (VPS13C). VPS13C mutations are associated with a distinct form of early-onset parkinsonism characterized by rapid and severe disease progression and early cognitive decline; the pathological features were striking and reminiscent of diffuse Lewy body disease. In cell models, VPS13C partly localized to the outer membrane of mitochondria. Silencing of VPS13C was associated with lower mitochondrial membrane potential, mitochondrial fragmentation, increased respiration rates, exacerbated PINK1/Parkin-dependent mitophagy, and transcriptional upregulation of PARK2 in response to mitochondrial damage. This work suggests that loss of function of VPS13C is a cause of autosomal-recessive early-onset parkinsonism with a distinctive phenotype of rapid and severe progression. Copyright © 2016 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  4. The Effects of Urethane on Rat Outer Hair Cells

    Directory of Open Access Journals (Sweden)

    Mingyu Fu

    2016-01-01

    Full Text Available The cochlea converts sound vibration into electrical impulses and amplifies the low-level sound signal. Urethane, a widely used anesthetic in animal research, has been shown to reduce the neural responses to auditory stimuli. However, the effects of urethane on cochlea, especially on the function of outer hair cells, remain largely unknown. In the present study, we compared the cochlear microphonic responses between awake and urethane-anesthetized rats. The results revealed that the amplitude of the cochlear microphonic was decreased by urethane, resulting in an increase in the threshold at all of the sound frequencies examined. To deduce the possible mechanism underlying the urethane-induced decrease in cochlear sensitivity, we examined the electrical response properties of isolated outer hair cells using whole-cell patch-clamp recording. We found that urethane hyperpolarizes the outer hair cell membrane potential in a dose-dependent manner and elicits larger outward current. This urethane-induced outward current was blocked by strychnine, an antagonist of the α9 subunit of the nicotinic acetylcholine receptor. Meanwhile, the function of the outer hair cell motor protein, prestin, was not affected. These results suggest that urethane anesthesia is expected to decrease the responses of outer hair cells, whereas the frequency selectivity of cochlea remains unchanged.

  5. CoMIC, the hidden dynamics of mitochondrial inner compartments.

    Science.gov (United States)

    Cho, Bongki; Sun, Woong

    2017-12-01

    Mitochondria have evolutionarily, functionally and structurally distinct outer- (OMM) and inner-membranes (IMM). Thus, mitochondrial morphology is controlled by independent but coordinated activity of fission and fusion of the OMM and IMM. Constriction and division of the OMM are mediated by endocytosis-like machineries, which include dynamin-related protein 1 with additional cytosolic vesicle scissoring machineries such as actin filament and Dynamin 2. However, structural alteration of the IMM during mitochondrial division has been poorly understood. Recently, we found that the IMM and the inner compartments undergo transient and reversible constriction prior to the OMM division, which we termed CoMIC, Constriction of Mitochondrial Inner Compartment. In this short review, we further discuss the evolutionary perspective and the regulatory mechanism of CoMIC during mitochondrial division. [BMB Reports 2017; 50(12): 597-598].

  6. Hapalindole H Induces Apoptosis as an Inhibitor of NF-ĸB and Affects the Intrinsic Mitochondrial Pathway in PC-3 Androgen-insensitive Prostate Cancer Cells.

    Science.gov (United States)

    Acuña, Ulyana Muñoz; Mo, Shunyan; Zi, Jiachen; Orjala, Jimmy; DE Blanco, Esperanza J Carcache

    2018-06-01

    Prostate cancer presents the highest incidence rates among all cancers in men. Hapalindole H (Hap H), isolated from Fischerella muscicola (UTEX strain number LB1829) as part of our natural product anticancer drug discovery program, was found to be significantly active against prostate cancer cells. In this study, Hap H was tested for nuclear factor-kappa B (NF-ĸB) inhibition and selective cytotoxic activity against different cancer cell lines. The apoptotic effect was assessed on PC-3 prostate cancer cells by fluorescence-activated cell sorting analysis. The underlying mechanism that induced apoptosis was studied and the effect of Hap H on mitochondria was evaluated and characterized using western blot and flow cytometric analysis. Hap H was identified as a potent NF-ĸB inhibitor (0.76 μM) with selective cytotoxicity against the PC-3 prostate cancer cell line (0.02 μM). The apoptotic effect was studied on PC-3 cells. The results showed that treatment of PC-3 cells with Hap H reduced the formation of NAD(P)H, suggesting that the function of the outer mitochondrial membrane was negatively affected. Thus, the mitochondrial transmembrane potential was assessed in Hap H treated cells. The results showed that the outer mitochondrial membrane was disrupted as an increased amount of JC-1 monomers were detected in treated cells (78.3%) when compared to untreated cells (10.1%), also suggesting that a large number of treated cells went into an apoptotic state. Hap H was found to have potent NF-ĸB p65-inhibitory activity and induced apoptosis through the intrinsic mitochondrial pathway in hormone-independent PC-3 prostate cancer cells. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  7. Reversible infantile mitochondrial diseases.

    Science.gov (United States)

    Boczonadi, Veronika; Bansagi, Boglarka; Horvath, Rita

    2015-05-01

    Mitochondrial diseases are usually severe and progressive conditions; however, there are rare forms that show remarkable spontaneous recoveries. Two homoplasmic mitochondrial tRNA mutations (m.14674T>C/G in mt-tRNA(Glu)) have been reported to cause severe infantile mitochondrial myopathy in the first months of life. If these patients survive the first year of life by extensive life-sustaining measures they usually recover and develop normally. Another mitochondrial disease due to deficiency of the 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) causes severe liver failure in infancy, but similar to the reversible mitochondrial myopathy, within the first year of life these infants may also recover completely. Partial recovery has been noted in some other rare forms of mitochondrial disease due to deficiency of mitochondrial tRNA synthetases and mitochondrial tRNA modifying enzymes. Here we summarize the clinical presentation of these unique reversible mitochondrial diseases and discuss potential molecular mechanisms behind the reversibility. Understanding these mechanisms may provide the key to treatments of potential broader relevance in mitochondrial disease, where for the majority of the patients no effective treatment is currently available.

  8. Ubiquitination of specific mitochondrial matrix proteins

    International Nuclear Information System (INIS)

    Lehmann, Gilad; Ziv, Tamar; Braten, Ori; Admon, Arie; Udasin, Ronald G.; Ciechanover, Aaron

    2016-01-01

    Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems – at least partially – in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.

  9. Ubiquitination of specific mitochondrial matrix proteins

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Gilad [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ziv, Tamar [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Braten, Ori [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Admon, Arie [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Udasin, Ronald G. [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ciechanover, Aaron, E-mail: aaroncie@tx.technion.ac.il [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel)

    2016-06-17

    Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems – at least partially – in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.

  10. Preliminary X-ray crystallographic studies of yeast mitochondrial protein Tom70p

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yunkun [Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States); McCombs, Debbie; Nagy, Lisa; DeLucas, Lawrence [Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States); Sha, Bingdong, E-mail: bdsha@uab.edu [Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States)

    2006-03-01

    Tom70p is an important translocase of the outer membrane complex member and a major surface receptor of the protein-translocation machinery in the outer mitochondrial membrane. To investigate the mechanism by which Tom70p functions to deliver the mitochondrial protein precursors, the cytosolic fragment of yeast Tom70p (cTom70p) has been crystallized. Protein translocations across mitochondrial membranes play critical roles in mitochondrion biogenesis. Protein transport from the cell cytosol to the mitochondrial matrix is carried out by the translocase of the outer membrane (TOM) complex and the translocase of the inner membrane (TIM) complexes. Tom70p is an important TOM-complex member and a major surface receptor of the protein-translocation machinery in the outer mitochondrial membrane. To investigate the mechanism by which Tom70p functions to deliver the mitochondrial protein precursors, the cytosolic fragment of yeast Tom70p (cTom70p) was crystallized. The crystals diffract to 3.2 Å using a synchrotron X-ray source and belong to space group P2{sub 1}, with unit-cell parameters a = 44.89, b = 168.78, c = 83.41 Å, α = 90.00, β = 102.74, γ = 90.00°. There are two Tom70p molecules in one asymmetric unit, which corresponds to a solvent content of approximately 51%. Structure determination by MAD methods is under way.

  11. WORKSHOP: Inner space - outer space

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    During the first week of May, the Fermilab theoretical astrophysics group hosted an international conference on science at the interface of particle physics and cosmology/astrophysics. The conference (Inner Space-Outer Space) was attended by a very diverse group of more than 200 physical scientists, including astronomers, astrophysicists, cosmologists, low-temperature physicists, and elementary particle theorists and experimentalists. The common interest which brought this diverse group to gether is the connection between physics on the smallest scale probed by man - the realm of elementary particle physics - and physics on the largest scale imaginable (the entire Universe) - the realm of cosmology

  12. WORKSHOP: Inner space - outer space

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-09-15

    During the first week of May, the Fermilab theoretical astrophysics group hosted an international conference on science at the interface of particle physics and cosmology/astrophysics. The conference (Inner Space-Outer Space) was attended by a very diverse group of more than 200 physical scientists, including astronomers, astrophysicists, cosmologists, low-temperature physicists, and elementary particle theorists and experimentalists. The common interest which brought this diverse group to gether is the connection between physics on the smallest scale probed by man - the realm of elementary particle physics - and physics on the largest scale imaginable (the entire Universe) - the realm of cosmology.

  13. Outer scale of atmospheric turbulence

    Science.gov (United States)

    Lukin, Vladimir P.

    2005-10-01

    In the early 70's, the scientists in Italy (A.Consortini, M.Bertolotti, L.Ronchi), USA (R.Buser, Ochs, S.Clifford) and USSR (V.Pokasov, V.Lukin) almost simultaneously discovered the phenomenon of deviation from the power law and the effect of saturation for the structure phase function. During a period of 35 years we have performed successively the investigations of the effect of low-frequency spectral range of atmospheric turbulence on the optical characteristics. The influence of the turbulence models as well as a outer scale of turbulence on the characteristics of telescopes and systems of laser beam formations has been determined too.

  14. Human skeletal muscle mitochondrial capacity.

    Science.gov (United States)

    Rasmussen, U F; Rasmussen, H N

    2000-04-01

    Under aerobic work, the oxygen consumption and major ATP production occur in the mitochondria and it is therefore a relevant question whether the in vivo rates can be accounted for by mitochondrial capacities measured in vitro. Mitochondria were isolated from human quadriceps muscle biopsies in yields of approximately 45%. The tissue content of total creatine, mitochondrial protein and different cytochromes was estimated. A number of activities were measured in functional assays of the mitochondria: pyruvate, ketoglutarate, glutamate and succinate dehydrogenases, palmitoyl-carnitine respiration, cytochrome oxidase, the respiratory chain and the ATP synthesis. The activities involved in carbohydrate oxidation could account for in vivo oxygen uptakes of 15-16 mmol O2 min-1 kg-1 or slightly above the value measured at maximal work rates in the knee-extensor model of Saltin and co-workers, i.e. without limitation from the cardiac output. This probably indicates that the maximal oxygen consumption of the muscle is limited by the mitochondrial capacities. The in vitro activities of fatty acid oxidation corresponded to only 39% of those of carbohydrate oxidation. The maximal rate of free energy production from aerobic metabolism of glycogen was calculated from the mitochondrial activities and estimates of the DeltaG or ATP hydrolysis and the efficiency of the actin-myosin reaction. The resultant value was 20 W kg-1 or approximately 70% of the maximal in vivo work rates of which 10-20% probably are sustained by the anaerobic ATP production. The lack of aerobic in vitro ATP synthesis might reflect termination of some critical interplay between cytoplasm and mitochondria.

  15. Mechanisms of ER Stress-Mediated Mitochondrial Membrane Permeabilization.

    LENUS (Irish Health Repository)

    Gupta, Sanjeev

    2010-01-01

    During apoptosis, the process of mitochondrial outer membrane permeabilization (MOMP) represents a point-of-no-return as it commits the cell to death. Here we have assessed the role of caspases, Bcl-2 family members and the mitochondrial permeability transition pore on ER stress-induced MOMP and subsequent cell death. Induction of ER stress leads to upregulation of several genes such as Grp78, Edem1, Erp72, Atf4, Wars, Herp, p58ipk, and ERdj4 and leads to caspase activation, release of mitochondrial intermembrane proteins and dissipation of mitochondrial transmembrane potential (DeltaPsim). Mouse embryonic fibroblasts (MEFs) from caspase-9, -2 and, -3 knock-out mice were resistant to ER stress-induced apoptosis which correlated with decreased processing of pro-caspase-3 and -9. Furthermore, pretreatment of cells with caspase inhibitors (Boc-D.fmk and DEVD.fmk) attenuated ER stress-induced loss of DeltaPsim. However, only deficiency of caspase-9 and -2 could prevent ER stress-mediated loss of DeltaPsim. Bcl-2 overexpression or pretreatment of cells with the cell permeable BH4 domain (BH4-Tat) or the mitochondrial permeability transition pore inhibitors, bongkrekic acid or cyclosporine A, attenuated the ER stress-induced loss of DeltaPsim. These data suggest a role for caspase-9 and -2, Bcl-2 family members and the mitochondrial permeability transition pore in loss of mitochondrial membrane potential during ER stress-induced apoptosis.

  16. High-throughput respirometric assay identifies predictive toxicophore of mitochondrial injury

    Energy Technology Data Exchange (ETDEWEB)

    Wills, Lauren P. [MitoHealth Inc., Charleston, SC 29403 (United States); Beeson, Gyda C.; Trager, Richard E.; Lindsey, Christopher C. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425 (United States); Beeson, Craig C. [MitoHealth Inc., Charleston, SC 29403 (United States); Peterson, Yuri K. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425 (United States); Schnellmann, Rick G., E-mail: schnell@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425 (United States); Ralph H. Johnson VA Medical Center, Charleston, SC 29401 (United States)

    2013-10-15

    Many environmental chemicals and drugs negatively affect human health through deleterious effects on mitochondrial function. Currently there is no chemical library of mitochondrial toxicants, and no reliable methods for predicting mitochondrial toxicity. We hypothesized that discrete toxicophores defined by distinct chemical entities can identify previously unidentified mitochondrial toxicants. We used a respirometric assay to screen 1760 compounds (5 μM) from the LOPAC and ChemBridge DIVERSet libraries. Thirty-one of the assayed compounds decreased uncoupled respiration, a stress test for mitochondrial dysfunction, prior to a decrease in cell viability and reduced the oxygen consumption rate in isolated mitochondria. The mitochondrial toxicants were grouped by chemical similarity and two clusters containing four compounds each were identified. Cheminformatic analysis of one of the clusters identified previously uncharacterized mitochondrial toxicants from the ChemBridge DIVERSet. This approach will enable the identification of mitochondrial toxicants and advance the prediction of mitochondrial toxicity for both drug discovery and risk assessment. - Highlights: • Respirometric assay conducted in RPTC to create mitochondrial toxicant database. • Chemically similar mitochondrial toxicants aligned as mitochondrial toxicophores • Mitochondrial toxicophore identifies five novel mitochondrial toxicants.

  17. High-throughput respirometric assay identifies predictive toxicophore of mitochondrial injury

    International Nuclear Information System (INIS)

    Wills, Lauren P.; Beeson, Gyda C.; Trager, Richard E.; Lindsey, Christopher C.; Beeson, Craig C.; Peterson, Yuri K.; Schnellmann, Rick G.

    2013-01-01

    Many environmental chemicals and drugs negatively affect human health through deleterious effects on mitochondrial function. Currently there is no chemical library of mitochondrial toxicants, and no reliable methods for predicting mitochondrial toxicity. We hypothesized that discrete toxicophores defined by distinct chemical entities can identify previously unidentified mitochondrial toxicants. We used a respirometric assay to screen 1760 compounds (5 μM) from the LOPAC and ChemBridge DIVERSet libraries. Thirty-one of the assayed compounds decreased uncoupled respiration, a stress test for mitochondrial dysfunction, prior to a decrease in cell viability and reduced the oxygen consumption rate in isolated mitochondria. The mitochondrial toxicants were grouped by chemical similarity and two clusters containing four compounds each were identified. Cheminformatic analysis of one of the clusters identified previously uncharacterized mitochondrial toxicants from the ChemBridge DIVERSet. This approach will enable the identification of mitochondrial toxicants and advance the prediction of mitochondrial toxicity for both drug discovery and risk assessment. - Highlights: • Respirometric assay conducted in RPTC to create mitochondrial toxicant database. • Chemically similar mitochondrial toxicants aligned as mitochondrial toxicophores • Mitochondrial toxicophore identifies five novel mitochondrial toxicants

  18. Reperfusion promotes mitochondrial dysfunction following focal cerebral ischemia in rats.

    Directory of Open Access Journals (Sweden)

    Jun Li

    Full Text Available BACKGROUND AND PURPOSE: Mitochondrial dysfunction has been implicated in the cell death observed after cerebral ischemia, and several mechanisms for this dysfunction have been proposed. Reperfusion after transient cerebral ischemia may cause continued and even more severe damage to the brain. Many lines of evidence have shown that mitochondria suffer severe damage in response to ischemic injury. The purpose of this study was to observe the features of mitochondrial dysfunction in isolated mitochondria during the reperfusion period following focal cerebral ischemia. METHODS: Male Wistar rats were subjected to focal cerebral ischemia. Mitochondria were isolated using Percoll density gradient centrifugation. The isolated mitochondria were fixed for electron microscopic examination; calcium-induced mitochondrial swelling was quantified using spectrophotometry. Cyclophilin D was detected by Western blotting. Fluorescent probes were used to selectively stain mitochondria to measure their membrane potential and to measure reactive oxidative species production using flow cytometric analysis. RESULTS: Signs of damage were observed in the mitochondrial morphology after exposure to reperfusion. The mitochondrial swelling induced by Ca(2+ increased gradually with the increasing calcium concentration, and this tendency was exacerbated as the reperfusion time was extended. Cyclophilin D protein expression peaked after 24 hours of reperfusion. The mitochondrial membrane potential was decreased significantly during the reperfusion period, with the greatest decrease observed after 24 hours of reperfusion. The surge in mitochondrial reactive oxidative species occurred after 2 hours of reperfusion and was maintained at a high level during the reperfusion period. CONCLUSIONS: Reperfusion following focal cerebral ischemia induced significant mitochondrial morphological damage and Ca(2+-induced mitochondrial swelling. The mechanism of this swelling may be mediated by

  19. Mitochondrial Reactive Oxygen Species in Lipotoxic Hearts Induce Post-Translational Modifications of AKAP121, DRP1, and OPA1 That Promote Mitochondrial Fission.

    Science.gov (United States)

    Tsushima, Kensuke; Bugger, Heiko; Wende, Adam R; Soto, Jamie; Jenson, Gregory A; Tor, Austin R; McGlauflin, Rose; Kenny, Helena C; Zhang, Yuan; Souvenir, Rhonda; Hu, Xiao X; Sloan, Crystal L; Pereira, Renata O; Lira, Vitor A; Spitzer, Kenneth W; Sharp, Terry L; Shoghi, Kooresh I; Sparagna, Genevieve C; Rog-Zielinska, Eva A; Kohl, Peter; Khalimonchuk, Oleh; Schaffer, Jean E; Abel, E Dale

    2018-01-05

    Cardiac lipotoxicity, characterized by increased uptake, oxidation, and accumulation of lipid intermediates, contributes to cardiac dysfunction in obesity and diabetes mellitus. However, mechanisms linking lipid overload and mitochondrial dysfunction are incompletely understood. To elucidate the mechanisms for mitochondrial adaptations to lipid overload in postnatal hearts in vivo. Using a transgenic mouse model of cardiac lipotoxicity overexpressing ACSL1 (long-chain acyl-CoA synthetase 1) in cardiomyocytes, we show that modestly increased myocardial fatty acid uptake leads to mitochondrial structural remodeling with significant reduction in minimum diameter. This is associated with increased palmitoyl-carnitine oxidation and increased reactive oxygen species (ROS) generation in isolated mitochondria. Mitochondrial morphological changes and elevated ROS generation are also observed in palmitate-treated neonatal rat ventricular cardiomyocytes. Palmitate exposure to neonatal rat ventricular cardiomyocytes initially activates mitochondrial respiration, coupled with increased mitochondrial polarization and ATP synthesis. However, long-term exposure to palmitate (>8 hours) enhances ROS generation, which is accompanied by loss of the mitochondrial reticulum and a pattern suggesting increased mitochondrial fission. Mechanistically, lipid-induced changes in mitochondrial redox status increased mitochondrial fission by increased ubiquitination of AKAP121 (A-kinase anchor protein 121) leading to reduced phosphorylation of DRP1 (dynamin-related protein 1) at Ser637 and altered proteolytic processing of OPA1 (optic atrophy 1). Scavenging mitochondrial ROS restored mitochondrial morphology in vivo and in vitro. Our results reveal a molecular mechanism by which lipid overload-induced mitochondrial ROS generation causes mitochondrial dysfunction by inducing post-translational modifications of mitochondrial proteins that regulate mitochondrial dynamics. These findings provide a

  20. Mitochondrial morphology and cardiovascular disease

    OpenAIRE

    Ong, Sang-Bing; Hausenloy, Derek J.

    2010-01-01

    Mitochondria are dynamic and are able to interchange their morphology between elongated interconnected mitochondrial networks and a fragmented disconnected arrangement by the processes of mitochondrial fusion and fission, respectively. Changes in mitochondrial morphology are regulated by the mitochondrial fusion proteins (mitofusins 1 and 2, and optic atrophy 1) and the mitochondrial fission proteins (dynamin-related peptide 1 and mitochondrial fission protein 1) and have been implicated in a...

  1. Changes in outer membrane proteins of nontypable Haemophilus influenzae in patients with chronic obstructive pulmonary disease

    NARCIS (Netherlands)

    Groeneveld, K.; van Alphen, L.; Eijk, P. P.; Jansen, H. M.; Zanen, H. C.

    1988-01-01

    Five individual colonies of Haemophilus influenzae were isolated from each of one to three cultures of sputum collected from 18 patients with chronic obstructive pulmonary disease (COPD). The isolates were studied to investigate whether the major outer membrane proteins (MOMPs) changed during

  2. Mitochondrial oxidative function and type 2 diabetes

    DEFF Research Database (Denmark)

    Rabøl, Rasmus; Boushel, Robert; Dela, Flemming

    2006-01-01

    The cause of insulin resistance and type 2 diabetes is unknown. The major part of insulin-mediated glucose disposal takes place in the skeletal muscle, and increased amounts of intramyocellular lipid has been associated with insulin resistance and linked to decreased activity of mitochondrial...... oxidative phosphorylation. This review will cover the present knowledge and literature on the topics of the activity of oxidative enzymes and the electron transport chain (ETC) in skeletal muscle of patients with type 2 diabetes. Different methods of studying mitochondrial function are described, including...... biochemical measurements of oxidative enzyme and electron transport activity, isolation of mitochondria for measurements of respiration, and ATP production and indirect measurements of ATP production using nuclear magnetic resonance (NMR) - spectroscopy. Biochemical markers of mitochondrial content are also...

  3. Clueless, a protein required for mitochondrial function, interacts with the PINK1-Parkin complex in Drosophila

    Directory of Open Access Journals (Sweden)

    Aditya Sen

    2015-06-01

    Full Text Available Loss of mitochondrial function often leads to neurodegeneration and is thought to be one of the underlying causes of neurodegenerative diseases such as Parkinson's disease (PD. However, the precise events linking mitochondrial dysfunction to neuronal death remain elusive. PTEN-induced putative kinase 1 (PINK1 and Parkin (Park, either of which, when mutated, are responsible for early-onset PD, mark individual mitochondria for destruction at the mitochondrial outer membrane. The specific molecular pathways that regulate signaling between the nucleus and mitochondria to sense mitochondrial dysfunction under normal physiological conditions are not well understood. Here, we show that Drosophila Clueless (Clu, a highly conserved protein required for normal mitochondrial function, can associate with Translocase of the outer membrane (TOM 20, Porin and PINK1, and is thus located at the mitochondrial outer membrane. Previously, we found that clu genetically interacts with park in Drosophila female germ cells. Here, we show that clu also genetically interacts with PINK1, and our epistasis analysis places clu downstream of PINK1 and upstream of park. In addition, Clu forms a complex with PINK1 and Park, further supporting that Clu links mitochondrial function with the PINK1-Park pathway. Lack of Clu causes PINK1 and Park to interact with each other, and clu mutants have decreased mitochondrial protein levels, suggesting that Clu can act as a negative regulator of the PINK1-Park pathway. Taken together, these results suggest that Clu directly modulates mitochondrial function, and that Clu's function contributes to the PINK1-Park pathway of mitochondrial quality control.

  4. Ischemic preconditioning improves mitochondrial tolerance to experimental calcium overload.

    Science.gov (United States)

    Crestanello, Juan A; Doliba, Nicolai M; Babsky, Andriy M; Doliba, Natalia M; Niibori, Koki; Whitman, Glenn J R; Osbakken, Mary D

    2002-04-01

    Ca(2+) overload leads to mitochondrial uncoupling, decreased ATP synthesis, and myocardial dysfunction. Pharmacologically opening of mitochondrial K(ATP) channels decreases mitochondrial Ca(2+) uptake, improving mitochondrial function during Ca(2+) overload. Ischemic preconditioning (IPC), by activating mitochondrial K(ATP) channels, may attenuate mitochondrial Ca(2+) overload and improve mitochondrial function during reperfusion. The purpose of these experiments was to study the effect of IPC (1) on mitochondrial function and (2) on mitochondrial tolerance to experimental Ca(2+) overload. Rat hearts (n = 6/group) were subjected to (a) 30 min of equilibration, 25 min of ischemia, and 30 min of reperfusion (Control) or (b) two 5-min episodes of ischemic preconditioning, 25 min of ischemia, and 30 min of reperfusion (IPC). Developed pressure (DP) was measured. Heart mitochondria were isolated at end-Equilibration (end-EQ) and at end-Reperfusion (end-RP). Mitochondrial respiratory function (state 2, oxygen consumption with substrate only; state 3, oxygen consumption stimulated by ADP; state 4, oxygen consumption after cessation of ADP phosphorylation; respiratory control index (RCI, state 3/state 4); rate of oxidative phosphorylation (ADP/Deltat), and ADP:O ratio) was measured with polarography using alpha-ketoglutarate as a substrate in the presence of different Ca(2+) concentrations (0 to 5 x 10(-7) M) to simulate Ca(2+) overload. IPC improved DP at end-RP. IPC did not improve preischemic mitochondrial respiratory function or preischemic mitochondrial response to Ca(2+) loading. IPC improved state 3, ADP/Deltat, and RCI during RP. Low Ca(2+) levels (0.5 and 1 x 10(-7) M) stimulated mitochondrial function in both groups predominantly in IPC. The Control group showed evidence of mitochondrial uncoupling at lower Ca(2+) concentrations (1 x 10(-7) M). IPC preserved state 3 at high Ca(2+) concentrations. The cardioprotective effect of IPC results, in part, from

  5. Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Maynard, Scott; Keijzers, Guido; Gram, Martin

    2013-01-01

    . Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production...

  6. Highly rearranged mitochondrial genome in Nycteria parasites (Haemosporidia) from bats.

    Science.gov (United States)

    Karadjian, Gregory; Hassanin, Alexandre; Saintpierre, Benjamin; Gembu Tungaluna, Guy-Crispin; Ariey, Frederic; Ayala, Francisco J; Landau, Irene; Duval, Linda

    2016-08-30

    Haemosporidia parasites have mostly and abundantly been described using mitochondrial genes, and in particular cytochrome b (cytb). Failure to amplify the mitochondrial cytb gene of Nycteria parasites isolated from Nycteridae bats has been recently reported. Bats are hosts to a diverse and profuse array of Haemosporidia parasites that remain largely unstudied. There is a need to obtain more molecular data from chiropteran parasites. Such data would help to better understand the evolutionary history of Haemosporidia, which notably include the Plasmodium parasites, malaria's agents. We use next-generation sequencing to obtain the complete mitochondrial genome of Nycteria parasites from African Nycteris grandis (Nycteridae) and Rhinolophus alcyone (Rhinolophidae) and Asian Megaderma spasma (Megadermatidae). We report four complete mitochondrial genomes, including two rearranged mitochondrial genomes within Haemosporidia. Our results open outlooks into potentially undiscovered Haemosporidian diversity.

  7. Statistics of the outer radiation belt

    International Nuclear Information System (INIS)

    Rodgers, D.J.; Johnstone, A.D.

    1996-01-01

    The highly variable electron flux levels in the outer radiation belt come about by competition between time-dependent source and loss mechanisms. In order to identify some of the different mechanisms involved, we examine the statistics of the variability of fluxes at geostationary orbit. Data from the SEM-2 analyzer on Meteosat-3 and from GOES-7 are used. Correlation analysis is used to find time-delays between changes in flux at different energies. We see that low energy flux is added to this region during sub-storms and that higher energy fluxes appear after 2 or 3 days. Whilst the timescale for this process is brief compared to a complete cycle of the open-quote Recirculation close-quote energization process, it is consistent with the timescale of its final step endash outward radial diffusion. By isolating periods when no new injection of plasma occurs, we make an assessment of flux loss rates in a quiet magnetosphere. copyright 1996 American Institute of Physics

  8. Cold acclimation increases mitochondrial oxidative capacity without inducing mitochondrial uncoupling in goldfish white skeletal muscle

    Directory of Open Access Journals (Sweden)

    Reinaldo Sousa Dos Santos

    2012-11-01

    Goldfish have been used for cold acclimation studies, which have focused on changes in glycolytic and oxidative enzymes or alterations in lipid composition in skeletal muscle. Here we examine the effects of cold acclimation on the functional properties of isolated mitochondria and permeabilized fibers from goldfish white skeletal muscle, focusing on understanding the types of changes that occur in the mitochondrial respiratory states. We observed that cold acclimation promoted a significant increase in the mitochondrial oxygen consumption rates. Western blot analysis showed that UCP3 was raised by ∼1.5-fold in cold-acclimated muscle mitochondria. Similarly, we also evidenced a rise in the adenine nucleotide translocase content in cold-acclimated muscle mitochondria compared to warm-acclimated mitochondria (0.96±0.05 vs 0.68±0.02 nmol carboxyatractyloside mg−1 protein. This was followed by a 2-fold increment in the citrate synthase activity, which suggests a higher mitochondrial content in cold-acclimated goldfish. Even with higher levels of UCP3 and ANT, the effects of activator (palmitate and inhibitors (carboxyatractyloside and GDP on mitochondrial parameters were similar in both warm- and cold-acclimated goldfish. Thus, we propose that cold acclimation in goldfish promotes an increase in functional oxidative capacity, with higher mitochondrial content without changes in the mitochondrial uncoupling pathways.

  9. Localization of mRNAs coding for mitochondrial proteins in the yeast Saccharomyces cerevisiae

    OpenAIRE

    Gadir, Noga; Haim-Vilmovsky, Liora; Kraut-Cohen, Judith; Gerst, Jeffrey E.

    2011-01-01

    Targeted mRNA localization is a likely determinant of localized protein synthesis. To investigate whether mRNAs encoding mitochondrial proteins (mMPs) localize to mitochondria and, thus, might confer localized protein synthesis and import, we visualized endogenously expressed mMPs in vivo for the first time. We determined the localization of 24 yeast mMPs encoding proteins of the mitochondrial matrix, outer and inner membrane, and intermembrane space and found that many mMPs colocalize with m...

  10. Analysis of regional brain mitochondrial bioenergetics and susceptibility to mitochondrial inhibition utilizing a microplate based system

    Science.gov (United States)

    Sauerbeck, Andrew; Pandya, Jignesh; Singh, Indrapal; Bittman, Kevin; Readnower, Ryan; Bing, Guoying; Sullivan, Patrick

    2012-01-01

    The analysis of mitochondrial bioenergetic function typically has required 50–100 μg of protein per sample and at least 15 min per run when utilizing a Clark-type oxygen electrode. In the present work we describe a method utilizing the Seahorse Biosciences XF24 Flux Analyzer for measuring mitochondrial oxygen consumption simultaneously from multiple samples and utilizing only 5 μg of protein per sample. Utilizing this method we have investigated whether regionally based differences exist in mitochondria isolated from the cortex, striatum, hippocampus, and cerebellum. Analysis of basal mitochondrial bioenergetics revealed that minimal differences exist between the cortex, striatum, and hippocampus. However, the cerebellum exhibited significantly slower basal rates of Complex I and Complex II dependent oxygen consumption (p < 0.05). Mitochondrial inhibitors affected enzyme activity proportionally across all samples tested and only small differences existed in the effect of inhibitors on oxygen consumption. Investigation of the effect of rotenone administration on Complex I dependent oxygen consumption revealed that exposure to 10 pM rotenone led to a clear time dependent decrease in oxygen consumption beginning 12 min after administration (p < 0.05). These studies show that the utilization of this microplate based method for analysis of mitochondrial bioenergetics is effective at quantifying oxygen consumption simultaneously from multiple samples. Additionally, these studies indicate that minimal regional differences exist in mitochondria isolated from the cortex, striatum, or hippocampus. Furthermore, utilization of the mitochondrial inhibitors suggests that previous work indicating regionally specific deficits following systemic mitochondrial toxin exposure may not be the result of differences in the individual mitochondria from the affected regions. PMID:21402103

  11. The mitochondrial elongation factors MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Tong; Yu, Rong [Department of Oncology–Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm (Sweden); Jin, Shao-Bo [Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm (Sweden); Han, Liwei [Department of Oncology–Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm (Sweden); Lendahl, Urban [Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm (Sweden); Zhao, Jian, E-mail: Jian.Zhao@ki.se [Department of Oncology–Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm (Sweden); Nistér, Monica [Department of Oncology–Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm (Sweden)

    2013-11-01

    Mitochondria are dynamic organelles whose morphology is regulated by a complex balance of fission and fusion processes, and we still know relatively little about how mitochondrial dynamics is regulated. MIEF1 (also called MiD51) has recently been characterized as a key regulator of mitochondrial dynamics and in this report we explore the functions of its paralog MIEF2 (also called MiD49), to learn to what extent MIEF2 is functionally distinct from MIEF1. We show that MIEF1 and MIEF2 have many functions in common. Both are anchored in the mitochondrial outer membrane, recruit Drp1 from the cytoplasm to the mitochondrial surface and cause mitochondrial fusion, and MIEF2, like MIEF1, can interact with Drp1 and hFis1. MIEF1 and MIEF2, however, also differ in certain aspects. MIEF1 and MIEF2 are differentially expressed in human tissues during development. When overexpressed, MIEF2 exerts a stronger fusion-promoting effect than MIEF1, and in line with this, hFis1 and Mff can only partially revert the MIEF2-induced fusion phenotype, whereas MIEF1-induced fusion is reverted to a larger extent by hFis1 and Mff. MIEF2 forms high molecular weight oligomers, while MIEF1 is largely present as a dimer. Furthermore, MIEF1 and MIEF2 use distinct domains for oligomerization: in MIEF1, the region from amino acid residues 109–154 is required, whereas oligomerization of MIEF2 depends on amino acid residues 1 to 49, i.e. the N-terminal end. We also show that oligomerization of MIEF1 is not required for its mitochondrial localization and interaction with Drp1. In conclusion, our data suggest that the mitochondrial regulators MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics. - Highlights: • MIEF1 and MIEF2 recruit Drp1 to mitochondria and cause mitochondrial fusion. • MIEF2, like MIEF1, can interact with Drp1 and hFis1. • MIEF1 and MIEF2 are differentially expressed in human tissues during development. • MIEF2 exerts a stronger fusion

  12. The mitochondrial elongation factors MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics

    International Nuclear Information System (INIS)

    Liu, Tong; Yu, Rong; Jin, Shao-Bo; Han, Liwei; Lendahl, Urban; Zhao, Jian; Nistér, Monica

    2013-01-01

    Mitochondria are dynamic organelles whose morphology is regulated by a complex balance of fission and fusion processes, and we still know relatively little about how mitochondrial dynamics is regulated. MIEF1 (also called MiD51) has recently been characterized as a key regulator of mitochondrial dynamics and in this report we explore the functions of its paralog MIEF2 (also called MiD49), to learn to what extent MIEF2 is functionally distinct from MIEF1. We show that MIEF1 and MIEF2 have many functions in common. Both are anchored in the mitochondrial outer membrane, recruit Drp1 from the cytoplasm to the mitochondrial surface and cause mitochondrial fusion, and MIEF2, like MIEF1, can interact with Drp1 and hFis1. MIEF1 and MIEF2, however, also differ in certain aspects. MIEF1 and MIEF2 are differentially expressed in human tissues during development. When overexpressed, MIEF2 exerts a stronger fusion-promoting effect than MIEF1, and in line with this, hFis1 and Mff can only partially revert the MIEF2-induced fusion phenotype, whereas MIEF1-induced fusion is reverted to a larger extent by hFis1 and Mff. MIEF2 forms high molecular weight oligomers, while MIEF1 is largely present as a dimer. Furthermore, MIEF1 and MIEF2 use distinct domains for oligomerization: in MIEF1, the region from amino acid residues 109–154 is required, whereas oligomerization of MIEF2 depends on amino acid residues 1 to 49, i.e. the N-terminal end. We also show that oligomerization of MIEF1 is not required for its mitochondrial localization and interaction with Drp1. In conclusion, our data suggest that the mitochondrial regulators MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics. - Highlights: • MIEF1 and MIEF2 recruit Drp1 to mitochondria and cause mitochondrial fusion. • MIEF2, like MIEF1, can interact with Drp1 and hFis1. • MIEF1 and MIEF2 are differentially expressed in human tissues during development. • MIEF2 exerts a stronger fusion

  13. Mitochondrial-targeted DNA delivery using a DF-MITO-Porter, an innovative nano carrier with cytoplasmic and mitochondrial fusogenic envelopes

    International Nuclear Information System (INIS)

    Yamada, Yuma; Kawamura, Eriko; Harashima, Hideyoshi

    2012-01-01

    Mitochondrial gene therapy has the potential for curing a variety of diseases that are associated with mitochondrial DNA mutations and/or defects. To achieve this, it will be necessary to deliver therapeutic agents into the mitochondria in diseased cells. A number of mitochondrial drug delivery systems have been reported to date. However, reports of mitochondrial-targeted DNA delivery are limited. To achieve this, the therapeutic agent must be taken up by the cell (1), after which, the multi-processes associated with intracellular trafficking must be sophisticatedly regulated so as to release the agent from the endosome and deliver it to the cytosol (2) and to pass through the mitochondrial membrane (3). We report herein on the mitochondrial delivery of oligo DNA as a model therapeutic using a Dual Function (DF)-MITO-Porter, an innovative nano carrier designed for mitochondrial delivery. The critical structural elements of the DF-MITO-Porter include mitochondria-fusogenic inner envelopes and endosome-fusogenic outer envelopes, modified with octaarginine which greatly assists in cellular uptake. Inside the cell, the carrier passes through the endosomal and mitochondrial membranes via step-wise membrane fusion. When the oligo DNA was packaged in the DF-MITO-Porter, cellular uptake efficiency was strongly enhanced. Intracellular observation using confocal laser scanning microscopy showed that the DF-MITO-Porter was effectively released from endosomes. Moreover, the findings confirmed that the mitochondrial targeting activity of the DF-MITO-Porter was significantly higher than that of a carrier without outer endosome-fusogenic envelopes. These results support the conclusion that mitochondrial-targeted DNA delivery using a DF-MITO-Porter can be achieved when intracellular trafficking is optimally regulated.

  14. Mitochondrial-targeted DNA delivery using a DF-MITO-Porter, an innovative nano carrier with cytoplasmic and mitochondrial fusogenic envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yuma; Kawamura, Eriko; Harashima, Hideyoshi, E-mail: harasima@pharm.hokudai.ac.jp [Hokkaido University, Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences (Japan)

    2012-08-15

    Mitochondrial gene therapy has the potential for curing a variety of diseases that are associated with mitochondrial DNA mutations and/or defects. To achieve this, it will be necessary to deliver therapeutic agents into the mitochondria in diseased cells. A number of mitochondrial drug delivery systems have been reported to date. However, reports of mitochondrial-targeted DNA delivery are limited. To achieve this, the therapeutic agent must be taken up by the cell (1), after which, the multi-processes associated with intracellular trafficking must be sophisticatedly regulated so as to release the agent from the endosome and deliver it to the cytosol (2) and to pass through the mitochondrial membrane (3). We report herein on the mitochondrial delivery of oligo DNA as a model therapeutic using a Dual Function (DF)-MITO-Porter, an innovative nano carrier designed for mitochondrial delivery. The critical structural elements of the DF-MITO-Porter include mitochondria-fusogenic inner envelopes and endosome-fusogenic outer envelopes, modified with octaarginine which greatly assists in cellular uptake. Inside the cell, the carrier passes through the endosomal and mitochondrial membranes via step-wise membrane fusion. When the oligo DNA was packaged in the DF-MITO-Porter, cellular uptake efficiency was strongly enhanced. Intracellular observation using confocal laser scanning microscopy showed that the DF-MITO-Porter was effectively released from endosomes. Moreover, the findings confirmed that the mitochondrial targeting activity of the DF-MITO-Porter was significantly higher than that of a carrier without outer endosome-fusogenic envelopes. These results support the conclusion that mitochondrial-targeted DNA delivery using a DF-MITO-Porter can be achieved when intracellular trafficking is optimally regulated.

  15. Outer grid strap protruding spring repair apparatus

    International Nuclear Information System (INIS)

    Widener, W.H.

    1987-01-01

    This patent describes a nuclear fuel assembly grid spring repair apparatus for repairing a spring formed on an outer strap of a fuel assembly grid and having a portion protruding outwardly beyond the strap, the apparatus comprising: (a) a support frame defining an opening and having means defining a guide channel extending along the opening in a first direction; (b) means mounted on the frame and being adjustable for attaching the frame to the outer strap of the support grid so that the frame opening is aligned with the outwardly protruding spring on the outer strap; (c) an outer slide having a passageway defined therethrough and being mounted in the guide channel for reciprocable movement along the frame opening in the first direction for aligning the passageway with the outwardly protruding portion of the spring on the outer strap. The outer slide also has means defining a guide way extending along the passageway in a second direction generally orthogonal to the first direction; (d) a spring reset mechanism being operable for resetting the protruding spring to a nonprotruding position relative to the outer strap when the mechanism is aligned with the protruding portion of the spring; and (e) an inner slide supporting the spring reset mechanism and being mounted to the guide way for reciprocable movement along the passageway of the outer slide in the second direction for aligning the spring reset mechanism with the protruding portion of the spring on the outer strap

  16. Mechanism of neuroprotective mitochondrial remodeling by PKA/AKAP1.

    Directory of Open Access Journals (Sweden)

    Ronald A Merrill

    2011-04-01

    Full Text Available Mitochondrial shape is determined by fission and fusion reactions catalyzed by large GTPases of the dynamin family, mutation of which can cause neurological dysfunction. While fission-inducing protein phosphatases have been identified, the identity of opposing kinase signaling complexes has remained elusive. We report here that in both neurons and non-neuronal cells, cAMP elevation and expression of an outer-mitochondrial membrane (OMM targeted form of the protein kinase A (PKA catalytic subunit reshapes mitochondria into an interconnected network. Conversely, OMM-targeting of the PKA inhibitor PKI promotes mitochondrial fragmentation upstream of neuronal death. RNAi and overexpression approaches identify mitochondria-localized A kinase anchoring protein 1 (AKAP1 as a neuroprotective and mitochondria-stabilizing factor in vitro and in vivo. According to epistasis studies with phosphorylation site-mutant dynamin-related protein 1 (Drp1, inhibition of the mitochondrial fission enzyme through a conserved PKA site is the principal mechanism by which cAMP and PKA/AKAP1 promote both mitochondrial elongation and neuronal survival. Phenocopied by a mutation that slows GTP hydrolysis, Drp1 phosphorylation inhibits the disassembly step of its catalytic cycle, accumulating large, slowly recycling Drp1 oligomers at the OMM. Unopposed fusion then promotes formation of a mitochondrial reticulum, which protects neurons from diverse insults.

  17. Developing a biological dosimeter based on mitochondrial DNA

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S; Carlisle, S M; Unrau, P; Deugau, K V [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1996-12-31

    Direct measurement of deoxyribonucleic acid (DNA) damage from ionizing radiation may be advantageous in determining radiation radiation exposures and assessing their effects on atomic radiation workers. The mitochondrial DNA molecule is one potential cellular DNA target which is: fully defined and sequenced; present in many copies per cell; not vital to cellular survival; and less subject to DNA repair than nuclear DNA. A method is described to isolate and analyse normal mitochondrial DNA. We describe the developments needed to determine DNA damage in mitochondrial DNA. The target is to make a biological dosimeter. (author). 6 refs., 3 figs.

  18. Developing a biological dosimeter based on mitochondrial DNA

    International Nuclear Information System (INIS)

    Adams, S.; Carlisle, S.M.; Unrau, P.; Deugau, K.V.

    1995-01-01

    Direct measurement of deoxyribonucleic acid (DNA) damage from ionizing radiation may be advantageous in determining radiation radiation exposures and assessing their effects on atomic radiation workers. The mitochondrial DNA molecule is one potential cellular DNA target which is: fully defined and sequenced; present in many copies per cell; not vital to cellular survival; and less subject to DNA repair than nuclear DNA. A method is described to isolate and analyse normal mitochondrial DNA. We describe the developments needed to determine DNA damage in mitochondrial DNA. The target is to make a biological dosimeter. (author). 6 refs., 3 figs

  19. Hyperglycemia Alters the Schwann Cell Mitochondrial Proteome and Decreases Coupled Respiration in the Absence of Superoxide Production

    OpenAIRE

    Zhang, Liang; Yu, Cuijuan; Vasquez, Francisco E.; Galeva, Nadya; Onyango, Isaac; Swerdlow, Russell H.; Dobrowsky, Rick T.

    2010-01-01

    Hyperglycemia-induced mitochondrial dysfunction contributes to sensory neuron pathology in diabetic neuropathy. Although Schwann cells (SCs) also undergo substantial degeneration in diabetic neuropathy, the effect of hyperglycemia on SC mitochondrial proteome and mitochondrial function has not been examined. Stable isotope labeling with amino acids in cell culture (SILAC) was used to quantify the temporal effect of hyperglycemia on the mitochondrial proteome of primary SCs isolated from neona...

  20. Hepatocellular toxicity of benzbromarone: Effects on mitochondrial function and structure

    International Nuclear Information System (INIS)

    Felser, Andrea; Lindinger, Peter W.; Schnell, Dominik; Kratschmar, Denise V.; Odermatt, Alex; Mies, Suzette; Jenö, Paul; Krähenbühl, Stephan

    2014-01-01

    Highlights: • Benzbromarone impairs the electron transport chain and uncouples mitochondria. • Benzbromarone impairs mitochondrial β-oxidation by inhibiting fatty acid activation. • Benzbromarone disrupts the mitochondrial network and induces apoptosis. - Abstract: Benzbromarone is an uricosuric structurally related to amiodarone and a known mitochondrial toxicant. The aim of the current study was to improve our understanding in the molecular mechanisms of benzbromarone-associated hepatic mitochondrial toxicity. In HepG2 cells and primary human hepatocytes, ATP levels started to decrease in the presence of 25–50 μM benzbromarone for 24–48 h, whereas cytotoxicity was observed only at 100 μM. In HepG2 cells, benzbromarone decreased the mitochondrial membrane potential starting at 50 μM following incubation for 24 h. Additionally, in HepG2 cells, 50 μM benzbromarone for 24 h induced mitochondrial uncoupling,and decreased mitochondrial ATP turnover and maximal respiration. This was accompanied by an increased lactate concentration in the cell culture supernatant, reflecting increased glycolysis as a compensatory mechanism to maintain cellular ATP. Investigation of the electron transport chain revealed a decreased activity of all relevant enzyme complexes. Furthermore, treatment with benzbromarone was associated with increased cellular ROS production, which could be located specifically to mitochondria. In HepG2 cells and in isolated mouse liver mitochondria, benzbromarone also reduced palmitic acid metabolism due to an inhibition of the long-chain acyl CoA synthetase. In HepG2 cells, benzbromarone disrupted the mitochondrial network, leading to mitochondrial fragmentation and a decreased mitochondrial volume per cell. Cell death occurred by both apoptosis and necrosis. The study demonstrates that benzbromarone not only affects the function of mitochondria in HepG2 cells and human hepatocytes, but is also associated with profound changes in mitochondrial

  1. Epilepsy and Mitochondrial Dysfunction

    Directory of Open Access Journals (Sweden)

    Russell P. Saneto DO, PhD

    2017-10-01

    Full Text Available Epilepsy is a common manifestation of mitochondrial disease. In a large cohort of children and adolescents with mitochondrial disease (n = 180, over 48% of patients developed seizures. The majority (68% of patients were younger than 3 years and medically intractable (90%. The electroencephalographic pattern of multiregional epileptiform discharges over the left and right hemisphere with background slowing occurred in 62%. The epilepsy syndrome, infantile spasms, was seen in 17%. Polymerase γ mutations were the most common genetic etiology of seizures, representing Alpers-Huttenlocher syndrome (14%. The severity of disease in those patients with epilepsy was significant, as 13% of patients experienced early death. Simply the loss of energy production cannot explain the development of seizures or all patients with mitochondrial dysfunction would have epilepsy. Until the various aspects of mitochondrial physiology that are involved in proper brain development are understood, epilepsy and its treatment will remain unsatisfactory.

  2. Mitochondrial matrix delivery using MITO-Porter, a liposome-based carrier that specifies fusion with mitochondrial membranes

    International Nuclear Information System (INIS)

    Yasuzaki, Yukari; Yamada, Yuma; Harashima, Hideyoshi

    2010-01-01

    Mitochondria are the principal producers of energy in cells of higher organisms. It was recently reported that mutations and defects in mitochondrial DNA (mtDNA) are associated with various mitochondrial diseases including a variety of neurodegenerative and neuromuscular diseases. Therefore, an effective mitochondrial gene therapy and diagnosis would be expected to have great medical benefits. To achieve this, therapeutic agents need to be delivered into the innermost mitochondrial space (mitochondrial matrix), which contains the mtDNA pool. We previously reported on the development of MITO-Porter, a liposome-based carrier that introduces macromolecular cargos into mitochondria via membrane fusion. In this study, we provide a demonstration of mitochondrial matrix delivery and the visualization of mitochondrial genes (mtDNA) in living cells using the MITO-Porter. We first prepared MITO-Porter containing encapsulated propidium iodide (PI), a fluorescent dye used to stain nucleic acids to detect mtDNA. We then confirmed the emission of red-fluorescence from PI by conjugation with mtDNA, when the carriers were incubated in the presence of isolated rat liver mitochondria. Finally, intracellular observation by confocal laser scanning microscopy clearly verified that the MITO-Porter delivered PI to the mitochondrial matrix.

  3. Characterization of Botrytis cinerea isolates from chickpea: DNA ...

    African Journals Online (AJOL)

    Administrator

    2010-11-15

    Nov 15, 2010 ... 2Department of Plant Sciences, University of Hyderabad, Hyderabad 500 046, India. ... similarity of the isolates varied from 14-44%, and the isolates were separated ..... application to human mitochondrial DNA restriction sites.

  4. Improved method of measurement for outer leak

    International Nuclear Information System (INIS)

    Xu Guang

    2012-01-01

    Pneumatic pipeline is installed for the airborne radioactivity measurement equipment, air tightness and outer leak rate are essential for the testing of the characteristics, both in the national criteria and ISO standards, an improved practical method is available for the measurement of the outer air leak rate based on the engineering experiences for the equipment acceptance and testing procedure. (authors)

  5. The plant mitochondrial proteome

    DEFF Research Database (Denmark)

    Millar, A.H.; Heazlewood, J.L.; Kristensen, B.K.

    2005-01-01

    The plant mitochondrial proteome might contain as many as 2000-3000 different gene products, each of which might undergo post-translational modification. Recent studies using analytical methods, such as one-, two- and three-dimensional gel electrophoresis and one- and two-dimensional liquid...... context to be defined for them. There are indications that some of these proteins add novel activities to mitochondrial protein complexes in plants....

  6. Mitochondrial signaling in health and disease

    National Research Council Canada - National Science Library

    Orrenius, Sten; Packer, Lester; Cadenas, Enrique

    2012-01-01

    .... The text covers themes essential for the maintenance of mitochondrial activity, including electron transport and energy production, mitochondrial biogenesis and dynamics, mitochondrial signaling...

  7. Bcl-xL regulates mitochondrial energetics by stabilizing the inner membrane potential.

    Science.gov (United States)

    Chen, Ying-Bei; Aon, Miguel A; Hsu, Yi-Te; Soane, Lucian; Teng, Xinchen; McCaffery, J Michael; Cheng, Wen-Chih; Qi, Bing; Li, Hongmei; Alavian, Kambiz N; Dayhoff-Brannigan, Margaret; Zou, Shifa; Pineda, Fernando J; O'Rourke, Brian; Ko, Young H; Pedersen, Peter L; Kaczmarek, Leonard K; Jonas, Elizabeth A; Hardwick, J Marie

    2011-10-17

    Mammalian Bcl-x(L) protein localizes to the outer mitochondrial membrane, where it inhibits apoptosis by binding Bax and inhibiting Bax-induced outer membrane permeabilization. Contrary to expectation, we found by electron microscopy and biochemical approaches that endogenous Bcl-x(L) also localized to inner mitochondrial cristae. Two-photon microscopy of cultured neurons revealed large fluctuations in inner mitochondrial membrane potential when Bcl-x(L) was genetically deleted or pharmacologically inhibited, indicating increased total ion flux into and out of mitochondria. Computational, biochemical, and genetic evidence indicated that Bcl-x(L) reduces futile ion flux across the inner mitochondrial membrane to prevent a wasteful drain on cellular resources, thereby preventing an energetic crisis during stress. Given that F(1)F(O)-ATP synthase directly affects mitochondrial membrane potential and having identified the mitochondrial ATP synthase β subunit in a screen for Bcl-x(L)-binding partners, we tested and found that Bcl-x(L) failed to protect β subunit-deficient yeast. Thus, by bolstering mitochondrial energetic capacity, Bcl-x(L) may contribute importantly to cell survival independently of other Bcl-2 family proteins.

  8. Mitochondrial base excision repair assays

    DEFF Research Database (Denmark)

    Maynard, Scott; de Souza-Pinto, Nadja C; Scheibye-Knudsen, Morten

    2010-01-01

    The main source of mitochondrial DNA (mtDNA) damage is reactive oxygen species (ROS) generated during normal cellular metabolism. The main mtDNA lesions generated by ROS are base modifications, such as the ubiquitous 8-oxoguanine (8-oxoG) lesion; however, base loss and strand breaks may also occur....... Many human diseases are associated with mtDNA mutations and thus maintaining mtDNA integrity is critical. All of these lesions are repaired primarily by the base excision repair (BER) pathway. It is now known that mammalian mitochondria have BER, which, similarly to nuclear BER, is catalyzed by DNA...... glycosylases, AP endonuclease, DNA polymerase (POLgamma in mitochondria) and DNA ligase. This article outlines procedures for measuring oxidative damage formation and BER in mitochondria, including isolation of mitochondria from tissues and cells, protocols for measuring BER enzyme activities, gene...

  9. Trichothecene Mycotoxins Inhibit Mitochondrial Translation—Implication for the Mechanism of Toxicity

    Directory of Open Access Journals (Sweden)

    Susan McCormick

    2011-12-01

    Full Text Available Fusarium head blight (FHB reduces crop yield and results in contamination of grains with trichothecene mycotoxins. We previously showed that mitochondria play a critical role in the toxicity of a type B trichothecene. Here, we investigated the direct effects of type A and type B trichothecenes on mitochondrial translation and membrane integrity in Saccharomyces cerevisiae. Sensitivity to trichothecenes increased when functional mitochondria were required for growth, and trichothecenes inhibited mitochondrial translation at concentrations, which did not inhibit total translation. In organello translation in isolated mitochondria was inhibited by type A and B trichothecenes, demonstrating that these toxins have a direct effect on mitochondrial translation. In intact yeast cells trichothecenes showed dose-dependent inhibition of mitochondrial membrane potential and reactive oxygen species, but only at doses higher than those affecting mitochondrial translation. These results demonstrate that inhibition of mitochondrial translation is a primary target of trichothecenes and is not secondary to the disruption of mitochondrial membranes.

  10. Comparison of brain mitochondrial cytochrome c oxidase activity with cyanide LD(50) yields insight into the efficacy of prophylactics.

    Science.gov (United States)

    Marziaz, Mandy L; Frazier, Kathryn; Guidry, Paul B; Ruiz, Robyn A; Petrikovics, Ilona; Haines, Donovan C

    2013-01-01

    Cyanide inhibits cytochrome c oxidase, the terminal oxidase of the mitochondrial respiratory pathway, therefore inhibiting the cell oxygen utilization and resulting in the condition of histotoxic anoxia. The enzyme rhodanese detoxifies cyanide by utilizing sulfur donors to convert cyanide to thiocyanate, and new and improved sulfur donors are actively sought as researchers seek to improve cyanide prophylactics. We have determined brain cytochrome c oxidase activity as a marker for cyanide exposure for mice pre-treated with various cyanide poisoning prophylactics, including sulfur donors thiosulfate (TS) and thiotaurine (TT3). Brain mitochondria were isolated by differential centrifugation, the outer mitochondrial membrane was disrupted by a maltoside detergent, and the decrease in absorbance at 550 nm as horse heart ferrocytochrome c (generated by the dithiothreitol reduction of ferricytochrome c) was oxidized was monitored. Overall, the TS control prophylactic treatment provided significant protection of the cytochrome c oxidase activity. The TT3-treated mice showed reduced cytochrome c oxidase activity even in the absence of cyanide. In both treatment series, addition of exogenous Rh did not significantly enhance the prevention of cytochrome c oxidase inhibition, but the addition of sodium nitrite did. These findings can lead to a better understanding of the protection mechanism by various cyanide antidotal systems. Copyright © 2011 John Wiley & Sons, Ltd.

  11. Proteomics of Aggregatibacter actinomycetemcomitans Outer Membrane Vesicles.

    Directory of Open Access Journals (Sweden)

    Thomas Kieselbach

    Full Text Available Aggregatibacter actinomycetemcomitans is an oral and systemic pathogen associated with aggressive forms of periodontitis and with endocarditis. Outer membrane vesicles (OMVs released by this species have been demonstrated to deliver effector proteins such as cytolethal distending toxin (CDT and leukotoxin (LtxA into human host cells and to act as triggers of innate immunity upon carriage of NOD1- and NOD2-active pathogen-associated molecular patterns (PAMPs. To improve our understanding of the pathogenicity-associated functions that A. actinomycetemcomitans exports via OMVs, we studied the proteome of density gradient-purified OMVs from a rough-colony type clinical isolate, strain 173 (serotype e using liquid chromatography-tandem mass spectrometry (LC-MS/MS. This analysis yielded the identification of 151 proteins, which were found in at least three out of four independent experiments. Data are available via ProteomeXchange with identifier PXD002509. Through this study, we not only confirmed the vesicle-associated release of LtxA, and the presence of proteins, which are known to act as immunoreactive antigens in the human host, but we also identified numerous additional putative virulence-related proteins in the A. actinomycetemcomitans OMV proteome. The known and putative functions of these proteins include immune evasion, drug targeting, and iron/nutrient acquisition. In summary, our findings are consistent with an OMV-associated proteome that exhibits several offensive and defensive functions, and they provide a comprehensive basis to further disclose roles of A. actinomycetemcomitans OMVs in periodontal and systemic disease.

  12. Mitochondrial respiration in human viable platelets-Methodology and influence of gender, age and storage

    DEFF Research Database (Denmark)

    Sjövall, Fredrik; Ehinger, Johannes K H; Marelsson, Sigurður E

    2013-01-01

    Studying whole cell preparations with intact mitochondria and respiratory complexes has a clear benefit compared to isolated or disrupted mitochondria due to the dynamic interplay between mitochondria and other cellular compartments. Platelet mitochondria have a potential to serve as a source...... of human viable mitochondria when studying mitochondrial physiology and pathogenic mechanisms, as well as for the diagnostics of mitochondrial diseases. The objective of the present study was to perform a detailed evaluation of platelet mitochondrial respiration using high-resolution respirometry. Further...

  13. Incorporation of squalene into rod outer segments

    International Nuclear Information System (INIS)

    Keller, R.K.; Fliesler, S.J.

    1990-01-01

    We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from [ 3 H]acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms

  14. Small RNAs controlling outer membrane porins

    DEFF Research Database (Denmark)

    Valentin-Hansen, Poul; Johansen, Jesper; Rasmussen, Anders A

    2007-01-01

    are key regulators of environmental stress. Recent work has revealed an intimate interplay between small RNA regulation of outer membrane proteins and the stress-induced sigmaE-signalling system, which has an essential role in the maintenance of the integrity of the outer membrane.......Gene regulation by small non-coding RNAs has been recognized as an important post-transcriptional regulatory mechanism for several years. In Gram-negative bacteria such as Escherichia coli and Salmonella, these RNAs control stress response and translation of outer membrane proteins and therefore...

  15. Mitochondrial dysfunction in obesity.

    Science.gov (United States)

    de Mello, Aline Haas; Costa, Ana Beatriz; Engel, Jéssica Della Giustina; Rezin, Gislaine Tezza

    2018-01-01

    Obesity leads to various changes in the body. Among them, the existing inflammatory process may lead to an increase in the production of reactive oxygen species (ROS) and cause oxidative stress. Oxidative stress, in turn, can trigger mitochondrial changes, which is called mitochondrial dysfunction. Moreover, excess nutrients supply (as it commonly is the case with obesity) can overwhelm the Krebs cycle and the mitochondrial respiratory chain, causing a mitochondrial dysfunction, and lead to a higher ROS formation. This increase in ROS production by the respiratory chain may also cause oxidative stress, which may exacerbate the inflammatory process in obesity. All these intracellular changes can lead to cellular apoptosis. These processes have been described in obesity as occurring mainly in peripheral tissues. However, some studies have already shown that obesity is also associated with changes in the central nervous system (CNS), with alterations in the blood-brain barrier (BBB) and in cerebral structures such as hypothalamus and hippocampus. In this sense, this review presents a general view about mitochondrial dysfunction in obesity, including related alterations, such as inflammation, oxidative stress, and apoptosis, and focusing on the whole organism, covering alterations in peripheral tissues, BBB, and CNS. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Multifunctional Mitochondrial AAA Proteases.

    Science.gov (United States)

    Glynn, Steven E

    2017-01-01

    Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle.

  17. Caffeine and acetaminophen association: Effects on mitochondrial bioenergetics.

    Science.gov (United States)

    Gonçalves, Débora F; de Carvalho, Nelson R; Leite, Martim B; Courtes, Aline A; Hartmann, Diane D; Stefanello, Sílvio T; da Silva, Ingrid K; Franco, Jéferson L; Soares, Félix A A; Dalla Corte, Cristiane L

    2018-01-15

    Many studies have been demonstrating the role of mitochondrial function in acetaminophen (APAP) hepatotoxicity. Since APAP is commonly consumed with caffeine, this work evaluated the effects of the combination of APAP and caffeine on hepatic mitochondrial bioenergetic function in mice. Mice were treated with caffeine (20mg/kg, intraperitoneal (i.p.)) or its vehicle and, after 30minutes, APAP (250mg/kg, i.p.) or its vehicle. Four hours later, livers were removed, and the parameters associated with mitochondrial function and oxidative stress were evaluated. Hepatic cellular oxygen consumption was evaluated by high-resolution respirometry (HRR). APAP treatment decreased cellular oxygen consumption and mitochondrial complex activities in the livers of mice. Additionally, treatment with APAP increased swelling of isolated mitochondria from mice livers. On the other hand, caffeine administered with APAP was able to improve hepatic mitochondrial bioenergetic function. Treatment with APAP increased lipid peroxidation and reactive oxygen species (ROS) production and decreased glutathione levels in the livers of mice. Caffeine administered with APAP was able to prevent lipid peroxidation and the ROS production in mice livers, which may be associated with the improvement of mitochondrial function caused by caffeine treatment. We suggest that the antioxidant effects of caffeine and/or its interactions with mitochondrial bioenergetics may be involved in its beneficial effects against APAP hepatotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Sam37 is crucial for formation of the mitochondrial TOM-SAM supercomplex, thereby promoting β-barrel biogenesis.

    Science.gov (United States)

    Wenz, Lena-Sophie; Ellenrieder, Lars; Qiu, Jian; Bohnert, Maria; Zufall, Nicole; van der Laan, Martin; Pfanner, Nikolaus; Wiedemann, Nils; Becker, Thomas

    2015-09-28

    Biogenesis of mitochondrial β-barrel proteins requires two preprotein translocases, the general translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). TOM and SAM form a supercomplex that promotes transfer of β-barrel precursors. The SAM core complex contains the channel protein Sam50, which cooperates with Sam35 in precursor recognition, and the peripheral membrane protein Sam37. The molecular function of Sam37 has been unknown. We report that Sam37 is crucial for formation of the TOM-SAM supercomplex. Sam37 interacts with the receptor domain of Tom22 on the cytosolic side of the mitochondrial outer membrane and links TOM and SAM complexes. Sam37 thus promotes efficient transfer of β-barrel precursors to the SAM complex. We conclude that Sam37 functions as a coupling factor of the translocase supercomplex of the mitochondrial outer membrane. © 2015 Wenz et al.

  19. Intracellular diffusion restrictions in isolated cardiomyocytes from rainbow trout

    Directory of Open Access Journals (Sweden)

    Birkedal Rikke

    2009-12-01

    Full Text Available Abstract Background Restriction of intracellular diffusion of adenine nucleotides has been studied intensively on adult rat cardiomyocytes. However, their cause and role in vivo is still uncertain. Intracellular membrane structures have been suggested to play a role. We therefore chose to study cardiomyocytes from rainbow trout (Oncorhynchus mykiss, which are thinner and have fewer intracellular membrane structures than adult rat cardiomyocytes. Previous studies suggest that trout permeabilized cardiac fibers also have diffusion restrictions. However, results from fibers may be affected by incomplete separation of the cells. This is avoided when studying permeabilized, isolated cardiomyocytes. The aim of this study was to verify the existence of diffusion restrictions in trout cardiomyocytes by comparing ADP-kinetics of mitochondrial respiration in permeabilized fibers, permeabilized cardiomyocytes and isolated mitochondria from rainbow trout heart. Experiments were performed at 10, 15 and 20°C in the absence and presence of creatine. Results Trout cardiomyocytes hypercontracted in the solutions used for mammalian cardiomyocytes. We developed a new solution in which they retained their shape and showed stable steady state respiration rates throughout an experiment. The apparent ADP-affinity of permeabilized cardiomyocytes was different from that of fibers. It was higher, independent of temperature and not increased by creatine. However, it was still about ten times lower than in isolated mitochondria. Conclusions The differences between fibers and cardiomyocytes suggest that results from trout heart fibers were affected by incomplete separation of the cells. However, the lower ADP-affinity of cardiomyocytes compared to isolated mitochondria indicate that intracellular diffusion restrictions are still present in trout cardiomyocytes despite their lower density of intracellular membrane structures. The lack of a creatine effect indicates that

  20. Mitochondrial Dynamics: Coupling Mitochondrial Fitness with Healthy Aging.

    Science.gov (United States)

    Sebastián, David; Palacín, Manuel; Zorzano, Antonio

    2017-03-01

    Aging is associated with a decline in mitochondrial function and the accumulation of abnormal mitochondria. However, the precise mechanisms by which aging promotes these mitochondrial alterations and the role of the latter in aging are still not fully understood. Mitochondrial dynamics is a key process regulating mitochondrial function and quality. Altered expression of some mitochondrial dynamics proteins has been recently associated with aging and with age-related alterations in yeast, Caenorhabditis elegans, mice, and humans. Here, we review the link between alterations in mitochondrial dynamics, aging, and age-related impairment. We propose that the dysregulation of mitochondrial dynamics leads to age-induced accumulation of unhealthy mitochondria and contributes to alterations linked to aging, such as diabetes and neurodegeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. WBSCR16 Is a Guanine Nucleotide Exchange Factor Important for Mitochondrial Fusion

    Directory of Open Access Journals (Sweden)

    Guorui Huang

    2017-07-01

    Full Text Available Regulated inter-mitochondrial fusion/fission is essential for maintaining optimal mitochondrial respiration and control of apoptosis and autophagy. In mammals, mitochondrial fusion is controlled by outer membrane GTPases MFN1 and MFN2 and by inner membrane (IM GTPase OPA1. Disordered mitochondrial fusion/fission contributes to various pathologies, and MFN2 or OPA1 mutations underlie neurodegenerative diseases. Here, we show that the WBSCR16 protein is primarily associated with the outer face of the inner mitochondrial membrane and is important for mitochondrial fusion. We provide evidence of a WBSCR16/OPA1 physical interaction in the intact cell and of a WBSCR16 function as an OPA1-specific guanine nucleotide exchange factor (GEF. Homozygosity for a Wbscr16 mutation causes early embryonic lethality, whereas neurons of mice heterozygous for the mutation have mitochondria with reduced membrane potential and increased susceptibility to fragmentation upon exposure to stress, suggesting roles for WBSCR16 deficits in neuronal pathologies.

  2. Analysis of proteins in Chlamydia trachomatis L2 outer membrane complex, COMC

    DEFF Research Database (Denmark)

    Birkelund, Svend; Morgan-Fisher, Marie; Timmerman, Evy

    2009-01-01

    The protein composition and N-terminal sequences of proteins in the outer membrane of Chlamydia trachomatis L2 were analysed following isolation of N-terminal peptides using combined fractional diagonal chromatography and identification by liquid chromatography tandem MS. Acetylation of primary a...

  3. Oscillations of the Outer Boundary of the Outer Radiation Belt During Sawtooth Oscillations

    Directory of Open Access Journals (Sweden)

    Jae-Hun Kim

    2006-09-01

    Full Text Available We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours sudden flux increases followed by slow flux decreases at the energy levels of ˜50-400 keV. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases due to the dipolarization (the stretching on the nightside as the sawtooth flux increases (decreases. This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

  4. Mitochondrial Dysfunction in Gliomas

    Czech Academy of Sciences Publication Activity Database

    Katsetos, C.D.; Anni, H.; Dráber, Pavel

    2013-01-01

    Roč. 20, č. 3 (2013), s. 216-227 ISSN 1071-9091 R&D Projects: GA MŠk LH12050 Institutional support: RVO:68378050 Keywords : gliomas * mitochondrial dysfunction * microtubule proteins Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.883, year: 2013

  5. Mitochondrial dysfunction in epilepsy

    Czech Academy of Sciences Publication Activity Database

    Folbergrová, Jaroslava; Kunz, W.S.

    2012-01-01

    Roč. 12, č. 1 (2012), s. 35-40 ISSN 1567-7249 R&D Projects: GA ČR(CZ) GA309/05/2015; GA ČR GA309/08/0292 Institutional research plan: CEZ:AV0Z50110509 Keywords : epilepsy * mitochondrial dysfunction * neurodegeneration Subject RIV: FH - Neurology Impact factor: 4.025, year: 2012

  6. Elastocapillary Instability in Mitochondrial Fission

    Science.gov (United States)

    Gonzalez-Rodriguez, David; Sart, Sébastien; Babataheri, Avin; Tareste, David; Barakat, Abdul I.; Clanet, Christophe; Husson, Julien

    2015-08-01

    Mitochondria are dynamic cell organelles that constantly undergo fission and fusion events. These dynamical processes, which tightly regulate mitochondrial morphology, are essential for cell physiology. Here we propose an elastocapillary mechanical instability as a mechanism for mitochondrial fission. We experimentally induce mitochondrial fission by rupturing the cell's plasma membrane. We present a stability analysis that successfully explains the observed fission wavelength and the role of mitochondrial morphology in the occurrence of fission events. Our results show that the laws of fluid mechanics can describe mitochondrial morphology and dynamics.

  7. Mitochondrial events responsible for morphine's cardioprotection against ischemia/reperfusion injury

    International Nuclear Information System (INIS)

    He, Haiyan; Huh, Jin; Wang, Huihua; Kang, Yi; Lou, Jianshi; Xu, Zhelong

    2016-01-01

    Morphine may induce cardioprotection by targeting mitochondria, but little is known about the exact mitochondrial events that mediate morphine's protection. We aimed to address the role of the mitochondrial Src tyrosine kinase in morphine's protection. Isolated rat hearts were subjected to 30 min ischemia and 2 h of reperfusion. Morphine was given before the onset of ischemia. Infarct size and troponin I release were measured to evaluate cardiac injury. Oxidative stress was evaluated by measuring mitochondrial protein carbonylation and mitochondrial ROS generation. HL-1 cells were subjected to simulated ischemia/reperfusion and LDH release and mitochondrial membrane potential (ΔΨm) were measured. Morphine reduced infarct size as well as cardiac troponin I release which were aborted by the selective Src tyrosine kinase inhibitors PP2 and Src-I1. Morphine also attenuated LDH release and prevented a loss of ΔΨm at reperfusion in a Src tyrosine kinase dependent manner in HL-1 cells. However, morphine failed to reduce LDH release in HL-1 cells transfected with Src siRNA. Morphine increased mitochondrial Src phosphorylation at reperfusion and this was abrogated by PP2. Morphine attenuated mitochondrial protein carbonylation and mitochondrial superoxide generation at reperfusion through Src tyrosine kinase. The inhibitory effect of morphine on the mitochondrial complex I activity was reversed by PP2. These data suggest that morphine induces cardioprotection by preventing mitochondrial oxidative stress through mitochondrial Src tyrosine kinase. Inhibition of mitochondrial complex I at reperfusion by Src tyrosine kinase may account for the prevention of mitochondrial oxidative stress by morphine. - Highlights: • Morphine induced mito-Src phosphorylation and reduced infarct size in rat hearts. • Morphine failed to reduce I/R-induced LDH release in Src-silencing HL-1 cells. • Morphine prevented mitochondria damage caused by I/R through Src. • Morphine reduced

  8. Mitochondrial events responsible for morphine's cardioprotection against ischemia/reperfusion injury

    Energy Technology Data Exchange (ETDEWEB)

    He, Haiyan [Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070 (China); Department of Pharmacology, Tianjin Medical University, Tianjin 300070 (China); Huh, Jin [Department of Anesthesia and Pain Medicine, Medical College, Kangwon National University, Chuncheon City (Korea, Republic of); Wang, Huihua [Department of Anesthesiology, The Second Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province (China); Kang, Yi; Lou, Jianshi [Department of Pharmacology, Tianjin Medical University, Tianjin 300070 (China); Xu, Zhelong, E-mail: zxu@tmu.edu.cn [Department of Physiology & Pathophysiology, Tianjin Medical University, Tianjin 300070 (China)

    2016-01-01

    Morphine may induce cardioprotection by targeting mitochondria, but little is known about the exact mitochondrial events that mediate morphine's protection. We aimed to address the role of the mitochondrial Src tyrosine kinase in morphine's protection. Isolated rat hearts were subjected to 30 min ischemia and 2 h of reperfusion. Morphine was given before the onset of ischemia. Infarct size and troponin I release were measured to evaluate cardiac injury. Oxidative stress was evaluated by measuring mitochondrial protein carbonylation and mitochondrial ROS generation. HL-1 cells were subjected to simulated ischemia/reperfusion and LDH release and mitochondrial membrane potential (ΔΨm) were measured. Morphine reduced infarct size as well as cardiac troponin I release which were aborted by the selective Src tyrosine kinase inhibitors PP2 and Src-I1. Morphine also attenuated LDH release and prevented a loss of ΔΨm at reperfusion in a Src tyrosine kinase dependent manner in HL-1 cells. However, morphine failed to reduce LDH release in HL-1 cells transfected with Src siRNA. Morphine increased mitochondrial Src phosphorylation at reperfusion and this was abrogated by PP2. Morphine attenuated mitochondrial protein carbonylation and mitochondrial superoxide generation at reperfusion through Src tyrosine kinase. The inhibitory effect of morphine on the mitochondrial complex I activity was reversed by PP2. These data suggest that morphine induces cardioprotection by preventing mitochondrial oxidative stress through mitochondrial Src tyrosine kinase. Inhibition of mitochondrial complex I at reperfusion by Src tyrosine kinase may account for the prevention of mitochondrial oxidative stress by morphine. - Highlights: • Morphine induced mito-Src phosphorylation and reduced infarct size in rat hearts. • Morphine failed to reduce I/R-induced LDH release in Src-silencing HL-1 cells. • Morphine prevented mitochondria damage caused by I/R through Src. • Morphine

  9. Insight into mitochondrial structure and function from electron tomography.

    Science.gov (United States)

    Frey, T G; Renken, C W; Perkins, G A

    2002-09-10

    In recent years, electron tomography has provided detailed three-dimensional models of mitochondria that have redefined our concept of mitochondrial structure. The models reveal an inner membrane consisting of two components, the inner boundary membrane (IBM) closely apposed to the outer membrane and the cristae membrane that projects into the matrix compartment. These two components are connected by tubular structures of relatively uniform size called crista junctions. The distribution of crista junction sizes and shapes is predicted by a thermodynamic model based upon the energy of membrane bending, but proteins likely also play a role in determining the conformation of the inner membrane. Results of structural studies of mitochondria during apoptosis demonstrate that cytochrome c is released without detectable disruption of the outer membrane or extensive swelling of the mitochondrial matrix, suggesting the formation of an outer membrane pore large enough to allow passage of holo-cytochrome c. The possible compartmentation of inner membrane function between the IBM and the cristae membrane is also discussed.

  10. Characterization of mitochondrial respiratory chain energetics in the vestibular nucleus complex.

    Science.gov (United States)

    Ashton, John C; Khalessi, Amirala; Kapoor, Mohit; Clarkson, Andrew; Sammut, Ivan A; Darlington, Cynthia L; Smith, Paul F

    2005-04-01

    Despite having very high neuronal firing rates, the VNC does not have unusually high mitochondrial activity in vitro. This study is the first in which functionally active mitochondria from the hindbrain have been isolated and characterized. Neurons in the vestibular nucleus complex (VNC) have exceptionally high spontaneous firing rates. Neuronal mitochondria generate adenosine triphosphate critical for maintaining the membrane potentials required for axon firing. We therefore hypothesized a high rate of mitochondrial activity in the VNC. To test this hypothesis, we compared mitochondrial activity in the VNC with mitochondrial activity from another area of the hindbrain, the cerebellum. Mitochondrial respiratory activity was assessed by measuring oxidative phosphorylation and mitochondrial respiratory enzyme complex activity. Assay results were not significantly different in the VNC compared to those obtained with the cerebellum or with rat brain mitochondria in previous studies.

  11. Quantifying small molecule phenotypic effects using mitochondrial morpho-functional fingerprinting and machine learning

    Science.gov (United States)

    Blanchet, Lionel; Smeitink, Jan A. M.; van Emst-de Vries, Sjenet E.; Vogels, Caroline; Pellegrini, Mina; Jonckheere, An I.; Rodenburg, Richard J. T.; Buydens, Lutgarde M. C.; Beyrath, Julien; Willems, Peter H. G. M.; Koopman, Werner J. H.

    2015-01-01

    In primary fibroblasts from Leigh Syndrome (LS) patients, isolated mitochondrial complex I deficiency is associated with increased reactive oxygen species levels and mitochondrial morpho-functional changes. Empirical evidence suggests these aberrations constitute linked therapeutic targets for small chemical molecules. However, the latter generally induce multiple subtle effects, meaning that in vitro potency analysis or single-parameter high-throughput cell screening are of limited use to identify these molecules. We combine automated image quantification and artificial intelligence to discriminate between primary fibroblasts of a healthy individual and a LS patient based upon their mitochondrial morpho-functional phenotype. We then evaluate the effects of newly developed Trolox variants in LS patient cells. This revealed that Trolox ornithylamide hydrochloride best counterbalanced mitochondrial morpho-functional aberrations, effectively scavenged ROS and increased the maximal activity of mitochondrial complexes I, IV and citrate synthase. Our results suggest that Trolox-derived antioxidants are promising candidates in therapy development for human mitochondrial disorders.

  12. Outer planet probe cost estimates: First impressions

    Science.gov (United States)

    Niehoff, J.

    1974-01-01

    An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

  13. Identification of two products of mitochondrial protein synthesis associated with mitochondrial adenosine triphosphatase from Neurospora crassa

    International Nuclear Information System (INIS)

    Jackl, G.; Sebald, W.

    1975-01-01

    Soluble mitochondrial ATPase (F 1 ) isolated from Neurospora crassa is resolved by dodecyl-sulfate-gel electrophoresis into five polypeptide bands with apparent molecular weights of 59,000, 55,000, 36,000, 15,000 and 12,000. At least nine further polypeptides remain associated with ATPase after disintegration of mitochondria with Triton X-100 as shown by the analysis of an immunoprecipitate obtained with antiserum to F 1 ATPase. Two of the associated polypeptides with apparent molecular weights of 19,000 and 11,000 are translated on mitochondrial ribosomes, as demonstrated by incorporation in vivo of radioactive leucine in the presence of specific inhibitors of mitochondrial (chloramphenicol) and extramitochondrial (cycloheximide) protein synthesis. The appearance of mitochondrial translation products in the immunoprecipitated ATPase complex is inhibited by cycloheximide. The same applies for some of the extramitochondrial translation products in the presence of chloramphenicol. This suggests that both types of polypeptides are necessary for the assembly of the ATPase complex. (orig.) [de

  14. Use the Protonmotive Force: Mitochondrial Uncoupling and Reactive Oxygen Species.

    Science.gov (United States)

    Berry, Brandon J; Trewin, Adam J; Amitrano, Andrea M; Kim, Minsoo; Wojtovich, Andrew P

    2018-04-04

    Mitochondrial respiration results in an electrochemical proton gradient, or protonmotive force (pmf), across the mitochondrial inner membrane. The pmf is a form of potential energy consisting of charge (∆ψ m ) and chemical (∆pH) components, that together drive ATP production. In a process called uncoupling, proton leak into the mitochondrial matrix independent of ATP production dissipates the pmf and energy is lost as heat. Other events can directly dissipate the pmf independent of ATP production as well, such as chemical exposure or mechanisms involving regulated mitochondrial membrane electrolyte transport. Uncoupling has defined roles in metabolic plasticity and can be linked through signal transduction to physiologic events. In the latter case, the pmf impacts mitochondrial reactive oxygen species (ROS) production. Although capable of molecular damage, ROS also have signaling properties that depend on the timing, location, and quantity of their production. In this review, we provide a general overview of mitochondrial ROS production, mechanisms of uncoupling, and how these work in tandem to affect physiology and pathologies, including obesity, cardiovascular disease, and immunity. Overall, we highlight that isolated bioenergetic models-mitochondria and cells-only partially recapitulate the complex link between the pmf and ROS signaling that occurs in vivo. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Mitochondrial introgression suggests extensive ancestral hybridization events among Saccharomyces species.

    Science.gov (United States)

    Peris, David; Arias, Armando; Orlić, Sandi; Belloch, Carmela; Pérez-Través, Laura; Querol, Amparo; Barrio, Eladio

    2017-03-01

    Horizontal gene transfer (HGT) in eukaryotic plastids and mitochondrial genomes is common, and plays an important role in organism evolution. In yeasts, recent mitochondrial HGT has been suggested between S. cerevisiae and S. paradoxus. However, few strains have been explored given the lack of accurate mitochondrial genome annotations. Mitochondrial genome sequences are important to understand how frequent these introgressions occur, and their role in cytonuclear incompatibilities and fitness. Indeed, most of the Bateson-Dobzhansky-Muller genetic incompatibilities described in yeasts are driven by cytonuclear incompatibilities. We herein explored the mitochondrial inheritance of several worldwide distributed wild Saccharomyces species and their hybrids isolated from different sources and geographic origins. We demonstrated the existence of several recombination points in mitochondrial region COX2-ORF1, likely mediated by either the activity of the protein encoded by the ORF1 (F-SceIII) gene, a free-standing homing endonuclease, or mostly facilitated by A+T tandem repeats and regions of integration of GC clusters. These introgressions were shown to occur among strains of the same species and among strains of different species, which suggests a complex model of Saccharomyces evolution that involves several ancestral hybridization events in wild environments. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Mitochondrial nucleoid interacting proteins support mitochondrial protein synthesis.

    Science.gov (United States)

    He, J; Cooper, H M; Reyes, A; Di Re, M; Sembongi, H; Litwin, T R; Gao, J; Neuman, K C; Fearnley, I M; Spinazzola, A; Walker, J E; Holt, I J

    2012-07-01

    Mitochondrial ribosomes and translation factors co-purify with mitochondrial nucleoids of human cells, based on affinity protein purification of tagged mitochondrial DNA binding proteins. Among the most frequently identified proteins were ATAD3 and prohibitin, which have been identified previously as nucleoid components, using a variety of methods. Both proteins are demonstrated to be required for mitochondrial protein synthesis in human cultured cells, and the major binding partner of ATAD3 is the mitochondrial ribosome. Altered ATAD3 expression also perturbs mtDNA maintenance and replication. These findings suggest an intimate association between nucleoids and the machinery of protein synthesis in mitochondria. ATAD3 and prohibitin are tightly associated with the mitochondrial membranes and so we propose that they support nucleic acid complexes at the inner membrane of the mitochondrion.

  17. Inhibition of NAPDH Oxidase 2 (NOX2 Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Leroy C Joseph

    Full Text Available Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity.

  18. MITOCHONDRIAL NEUROGASTROINTESTINAL ENCEPHALOMYOPATHY (MNGIE

    Directory of Open Access Journals (Sweden)

    P. Ayatollahi

    2006-06-01

    Full Text Available Mitochondrial neurogastrointestinal encephalo-myopathy (MNGIE is a rare autosomal recessive disease caused by thymidine phosphorylase (TP gene mutation. Here we report a patient with MNGIE in whom sensorimotor polyneuropathy was the first presenting symptom and had a fluctuating course. This 26-year-old female patient developed acute-onset demyelinating polyneuropathy from the age of 6 with two relapses later on. In addition, she had gastrointestinal symptoms (diarrhea, recurrent abdominal pain, progressive weight loss and ophthalmoparesis. Brain magnetic resonance imaging showed white matter abnormalities, and muscle biopsy showed ragged red fibers. This constellation of clinical and laboratory findings raised the diagnosis of mitochondrial neurogastrointestinal encephalomyopathy (MNGIE. This report highlights the uncommon clinical characteristics of this rare disease.

  19. 27 CFR 9.207 - Outer Coastal Plain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Outer Coastal Plain. 9.207... Outer Coastal Plain. (a) Name. The name of the viticultural area described in this section is “Outer Coastal Plain”. For purposes of part 4 of this chapter, “Outer Coastal Plain” is a term of viticultural...

  20. The mitochondrial uncoupling proteins

    OpenAIRE

    Ledesma, Amalia; de Lacoba, Mario García; Rial, Eduardo

    2002-01-01

    The uncoupling proteins (UCPs) are transporters, present in the mitochondrial inner membrane, that mediate a regulated discharge of the proton gradient that is generated by the respiratory chain. This energy-dissipatory mechanism can serve functions such as thermogenesis, maintenance of the redox balance, or reduction in the production of reactive oxygen species. Some UCP homologs may not act as true uncouplers, however, and their activity has yet to be defined. The UCPs are integral membrane...

  1. Isolation and quantification of major chlorogenic acids in three major instant coffee brands and their potential effects on H2O2-induced mitochondrial membrane depolarization and apoptosis in PC-12 cells

    Science.gov (United States)

    Coffee is a most consumed drink worldwide. In this paper, from three commercially available instant coffees, major chlorogenic acids were isolated and quantified using HPLC and NMR spectroscopic methods. Also, their anti-oxidant and anti-inflammatory activities were determined using DPPH-radical sca...

  2. Mitochondrial transcription factor A (Tfam) gene sequencing and mitochondrial evaluation in inherited retinal dysplasia in miniature schnauzer dogs.

    Science.gov (United States)

    Bauer, Bianca S; Forsyth, George W; Sandmeyer, Lynne S; Grahn, Bruce H

    2011-04-01

    Mitochondrial transcription factor A (Tfam) has been implicated in the pathogenesis of retinal dysplasia in miniature schnauzer dogs and it has been proposed that affected dogs have altered mitochondrial numbers, size, and morphology. To test these hypotheses the Tfam gene of affected and normal miniature schnauzer dogs with retinal dysplasia was sequenced and lymphocyte mitochondria were quantified, measured, and the morphology was compared in normal and affected dogs using transmission electron microscopy. For Tfam sequencing, retina, retinal pigment epithelium (RPE), and whole blood samples were collected. Total RNA was isolated from the retina and RPE and reverse transcribed to make cDNA. Genomic DNA was extracted from white blood cell pellets obtained from the whole blood samples. The Tfam coding sequence, 5' promoter region, intron1 and the 3' non-coding sequence of normal and affected dogs were amplified using polymerase chain reaction (PCR), cloned and sequenced. For electron microscopy, lymphocytes from affected and normal dogs were photographed and the mitochondria within each cross-section were identified, quantified, and the mitochondrial area (μm²) per lymphocyte cross-section was calculated. Lastly, using a masked technique, mitochondrial morphology was compared between the 2 groups. Sequencing of the miniature schnauzer Tfam gene revealed no functional sequence variation between affected and normal dogs. Lymphocyte and mitochondrial area, mitochondrial quantification, and morphology assessment also revealed no significant difference between the 2 groups. Further investigation into other candidate genes or factors causing retinal dysplasia in the miniature schnauzer is warranted.

  3. MITOCHONDRIAL BKCa CHANNEL

    Directory of Open Access Journals (Sweden)

    Enrique eBalderas

    2015-03-01

    Full Text Available Since its discovery in a glioma cell line 15 years ago, mitochondrial BKCa channel (mitoBKCa has been studied in brain cells and cardiomyocytes sharing general biophysical properties such as high K+ conductance (~300 pS, voltage-dependency and Ca2+-sensitivity. Main advances in deciphering the molecular composition of mitoBKCa have included establishing that it is encoded by the Kcnma1 gene, that a C-terminal splice insert confers mitoBKCa ability to be targeted to cardiac mitochondria, and evidence for its potential coassembly with β subunits. Notoriously, β1 subunit directly interacts with cytochrome c oxidase and mitoBKCa can be modulated by substrates of the respiratory chain. mitoBKCa channel has a central role in protecting the heart from ischemia, where pharmacological activation of the channel impacts the generation of reactive oxygen species and mitochondrial Ca2+ preventing cell death likely by impeding uncontrolled opening of the mitochondrial transition pore. Supporting this view, inhibition of mitoBKCa with Iberiotoxin, enhances cytochrome c release from glioma mitochondria. Many tantalizing questions remain. Some of them are: how is mitoBKCa coupled to the respiratory chain? Does mitoBKCa play non-conduction roles in mitochondria physiology? Which are the functional partners of mitoBKCa? What are the roles of mitoBKCa in other cell types? Answers to these questions are essential to define the impact of mitoBKCa channel in mitochondria biology and disease.

  4. Replicating animal mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Emily A. McKinney

    2013-01-01

    Full Text Available The field of mitochondrial DNA (mtDNA replication has been experiencing incredible progress in recent years, and yet little is certain about the mechanism(s used by animal cells to replicate this plasmid-like genome. The long-standing strand-displacement model of mammalian mtDNA replication (for which single-stranded DNA intermediates are a hallmark has been intensively challenged by a new set of data, which suggests that replication proceeds via coupled leading-and lagging-strand synthesis (resembling bacterial genome replication and/or via long stretches of RNA intermediates laid on the mtDNA lagging-strand (the so called RITOLS. The set of proteins required for mtDNA replication is small and includes the catalytic and accessory subunits of DNA polymerase y, the mtDNA helicase Twinkle, the mitochondrial single-stranded DNA-binding protein, and the mitochondrial RNA polymerase (which most likely functions as the mtDNA primase. Mutations in the genes coding for the first three proteins are associated with human diseases and premature aging, justifying the research interest in the genetic, biochemical and structural properties of the mtDNA replication machinery. Here we summarize these properties and discuss the current models of mtDNA replication in animal cells.

  5. Adaptive changes in renal mitochondrial redox status in diabetic nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Putt, David A.; Zhong, Qing; Lash, Lawrence H., E-mail: l.h.lash@wayne.edu

    2012-01-15

    Nephropathy is a serious and common complication of diabetes. In the streptozotocin (STZ)-treated rat model of diabetes, nephropathy does not typically develop until 30 to 45 days post-injection, although hyperglycemia occurs within 24 h. We tested the hypothesis that chronic hyperglycemia results in a modest degree of oxidative stress that is accompanied by compensatory changes in certain antioxidants and mitochondrial redox status. We propose that as kidneys progress to a state of diabetic nephropathy, further adaptations occur in mitochondrial redox status. Basic parameters of renal function in vivo and several parameters of mitochondrial function and glutathione (GSH) and redox status in isolated renal cortical mitochondria from STZ-treated and age-matched control rats were examined at 30 days and 90 days post-injection. While there was no effect of diabetes on blood urea nitrogen, measurement of other, more sensitive parameters, such as urinary albumin and protein, and histopathology showed significant and progressive worsening in diabetic rats. Thus, renal function is compromised even prior to the onset of frank nephropathy. Changes in mitochondrial respiration and enzyme activities indicated existence of a hypermetabolic state. Higher mitochondrial GSH content and rates of GSH transport into mitochondria in kidneys from diabetic rats were only partially due to changes in expression of mitochondrial GSH carriers and were mostly due to higher substrate supply. Although there are few clear indicators of oxidative stress, there are several redox changes that occur early and change further as nephropathy progresses, highlighting the complexity of the disease. Highlights: ►Adaptive changes in renal mitochondrial and redox status in diabetic rats. ►Modest renal dysfunction even prior to onset of nephropathy. ►Elevated concentrations of mitochondrial GSH in diabetic kidneys. ►Change in GSH due partly to increased protein expression of transporter.

  6. Adaptive changes in renal mitochondrial redox status in diabetic nephropathy

    International Nuclear Information System (INIS)

    Putt, David A.; Zhong, Qing; Lash, Lawrence H.

    2012-01-01

    Nephropathy is a serious and common complication of diabetes. In the streptozotocin (STZ)-treated rat model of diabetes, nephropathy does not typically develop until 30 to 45 days post-injection, although hyperglycemia occurs within 24 h. We tested the hypothesis that chronic hyperglycemia results in a modest degree of oxidative stress that is accompanied by compensatory changes in certain antioxidants and mitochondrial redox status. We propose that as kidneys progress to a state of diabetic nephropathy, further adaptations occur in mitochondrial redox status. Basic parameters of renal function in vivo and several parameters of mitochondrial function and glutathione (GSH) and redox status in isolated renal cortical mitochondria from STZ-treated and age-matched control rats were examined at 30 days and 90 days post-injection. While there was no effect of diabetes on blood urea nitrogen, measurement of other, more sensitive parameters, such as urinary albumin and protein, and histopathology showed significant and progressive worsening in diabetic rats. Thus, renal function is compromised even prior to the onset of frank nephropathy. Changes in mitochondrial respiration and enzyme activities indicated existence of a hypermetabolic state. Higher mitochondrial GSH content and rates of GSH transport into mitochondria in kidneys from diabetic rats were only partially due to changes in expression of mitochondrial GSH carriers and were mostly due to higher substrate supply. Although there are few clear indicators of oxidative stress, there are several redox changes that occur early and change further as nephropathy progresses, highlighting the complexity of the disease. Highlights: ►Adaptive changes in renal mitochondrial and redox status in diabetic rats. ►Modest renal dysfunction even prior to onset of nephropathy. ►Elevated concentrations of mitochondrial GSH in diabetic kidneys. ►Change in GSH due partly to increased protein expression of transporter.

  7. TOM9.2 Is a Calmodulin-Binding Protein Critical for TOM Complex Assembly but Not for Mitochondrial Protein Import in Arabidopsis thaliana.

    Science.gov (United States)

    Parvin, Nargis; Carrie, Chris; Pabst, Isabelle; Läßer, Antonia; Laha, Debabrata; Paul, Melanie V; Geigenberger, Peter; Heermann, Ralf; Jung, Kirsten; Vothknecht, Ute C; Chigri, Fatima

    2017-04-03

    The translocon on the outer membrane of mitochondria (TOM) facilitates the import of nuclear-encoded proteins. The principal machinery of mitochondrial protein transport seems conserved in eukaryotes; however, divergence in the composition and structure of TOM components has been observed between mammals, yeast, and plants. TOM9, the plant homolog of yeast Tom22, is significantly smaller due to a truncation in the cytosolic receptor domain, and its precise function is not understood. Here we provide evidence showing that TOM9.2 from Arabidopsis thaliana is involved in the formation of mature TOM complex, most likely by influencing the assembly of the pore-forming subunit TOM40. Dexamethasone-induced RNAi gene silencing of TOM9.2 results in a severe reduction in the mature TOM complex, and the assembly of newly imported TOM40 into the complex is impaired. Nevertheless, mutant plants are fully viable and no obvious downstream effects of the loss of TOM complex, i.e., on mitochondrial import capacity, were observed. Furthermore, we found that TOM9.2 can bind calmodulin (CaM) in vitro and that CaM impairs the assembly of TOM complex in the isolated wild-type mitochondria, suggesting a regulatory role of TOM9.2 and a possible integration of TOM assembly into the cellular calcium signaling network. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  8. Import of desired nucleic acid sequences using addressing motif of mitochondrial ribosomal 5S-rRNA for fluorescent in vivo hybridization of mitochondrial DNA and RNA.

    Science.gov (United States)

    Zelenka, Jaroslav; Alán, Lukáš; Jabůrek, Martin; Ježek, Petr

    2014-04-01

    Based on the matrix-addressing sequence of mitochondrial ribosomal 5S-rRNA (termed MAM), which is naturally imported into mitochondria, we have constructed an import system for in vivo targeting of mitochondrial DNA (mtDNA) or mt-mRNA, in order to provide fluorescence hybridization of the desired sequences. Thus DNA oligonucleotides were constructed, containing the 5'-flanked T7 RNA polymerase promoter. After in vitro transcription and fluorescent labeling with Alexa Fluor(®) 488 or 647 dye, we obtained the fluorescent "L-ND5 probe" containing MAM and exemplar cargo, i.e., annealing sequence to a short portion of ND5 mRNA and to the light-strand mtDNA complementary to the heavy strand nd5 mt gene (5'-end 21 base pair sequence). For mitochondrial in vivo fluorescent hybridization, HepG2 cells were treated with dequalinium micelles, containing the fluorescent probes, bringing the probes proximally to the mitochondrial outer membrane and to the natural import system. A verification of import into the mitochondrial matrix of cultured HepG2 cells was provided by confocal microscopy colocalizations. Transfections using lipofectamine or probes without 5S-rRNA addressing MAM sequence or with MAM only were ineffective. Alternatively, the same DNA oligonucleotides with 5'-CACC overhang (substituting T7 promoter) were transcribed from the tetracycline-inducible pENTRH1/TO vector in human embryonic kidney T-REx®-293 cells, while mitochondrial matrix localization after import of the resulting unlabeled RNA was detected by PCR. The MAM-containing probe was then enriched by three-order of magnitude over the natural ND5 mRNA in the mitochondrial matrix. In conclusion, we present a proof-of-principle for mitochondrial in vivo hybridization and mitochondrial nucleic acid import.

  9. Outer-2-independent domination in graphs

    Indian Academy of Sciences (India)

    independent dominating set of a graph is a set of vertices of such that every vertex of ()\\ has a neighbor in and the maximum vertex degree of the subgraph induced by ()\\ is at most one. The outer-2-independent domination ...

  10. Intershell correlations in photoionization of outer shells

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Chernysheva, L.V. [A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Drukarev, E.G. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute, St. Petersburg 188300 (Russian Federation)

    2016-02-15

    We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

  11. Outer-2-independent domination in graphs

    Indian Academy of Sciences (India)

    Outer-2-independent domination in graphs. MARCIN KRZYWKOWSKI1,2,∗, DOOST ALI MOJDEH3 and MARYEM RAOOFI4. 1Department of Pure and Applied Mathematics, University of Johannesburg,. Johannesburg, South Africa. 2Faculty of Electronics, Telecommunications and Informatics, Gdansk University.

  12. Intershell correlations in photoionization of outer shells

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Chernysheva, L.V.; Drukarev, E.G.

    2016-01-01

    We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

  13. Mitochondrial functionality in female reproduction

    Directory of Open Access Journals (Sweden)

    Łukasz Gąsior

    2017-01-01

    Full Text Available In most animal species female germ cells are the source of mitochondrial genome for the whole body of individuals. As a source of mitochondrial DNA for future generations the mitochondria in the female germ line undergo dynamic quantitative and qualitative changes. In addition to maintaining the intact template of mitochondrial genome from one generation to another, mitochondrial role in oocytes is much more complex and pleiotropic. The quality of mitochondria determines the ability of meiotic divisions, fertilization ability, and activation after fertilization or sustaining development of a new embryo. The presence of normal number of functional mitochondria is also crucial for proper implantation and pregnancy maintaining. This article addresses issues of mitochondrial role and function in mammalian oocyte and presents new approaches in studies of mitochondrial function in female germ cells.

  14. Influenza virus PB1-F2 protein induces cell death through mitochondrial ANT3 and VDAC1.

    Directory of Open Access Journals (Sweden)

    Dmitriy Zamarin

    2005-09-01

    Full Text Available The influenza virus PB1-F2 is an 87-amino acid mitochondrial protein that previously has been shown to induce cell death, although the mechanism of apoptosis induction has remained unclear. In the process of characterizing its mechanism of action we found that the viral PB1-F2 protein sensitizes cells to apoptotic stimuli such as tumor necrosis factor alpha, as demonstrated by increased cleavage of caspase 3 substrates in PB1-F2-expressing cells. Moreover, treatment of purified mouse liver mitochondria with recombinant PB1-F2 protein resulted in cytochrome c release, loss of the mitochondrial membrane potential, and enhancement of tBid-induced mitochondrial permeabilization, suggesting a possible mechanism for the observed cellular sensitization to apoptosis. Using glutathione-S-transferase pulldowns with subsequent mass spectrometric analysis, we identified the mitochondrial interactors of the PB1-F2 protein and showed that the viral protein uniquely interacts with the inner mitochondrial membrane adenine nucleotide translocator 3 and the outer mitochondrial membrane voltage-dependent anion channel 1, both of which are implicated in the mitochondrial permeability transition during apoptosis. Consistent with this interaction, blockers of the permeability transition pore complex (PTPC inhibited PB1-F2-induced mitochondrial permeabilization. Based on our findings, we propose a model whereby the proapoptotic PB1-F2 protein acts through the mitochondrial PTPC and may play a role in the down-regulation of the host immune response to infection.

  15. Translation of mitochondrial proteins in digitonin-treated rat hepatocytes

    International Nuclear Information System (INIS)

    Kuzela, S.; Wielburski, A.; Nelson, B.D.

    1981-01-01

    Although it is now clear that up to 13 peptides may be encoded in mammalian mitochondrial DNA there is little agreement concerning the numbers of stable translation products detectable in these mitochondria. Part of this uncertainty is due to the low rates of labeling of mammalian mitochondrial translations products resulting from the relatively slow growth rates of mammalian cells. Indeed, it is often necessary to isolate mammalian mitochondria in order to analyze their translation products, and the isolation procedures could conceivably lead to artifacts from proteolysis or from the early release of nascent peptides. To circumvent this problem, it would be desirable to have available a mammalian system which combines the advantage of high rates of labeling of mitochondrial proteins with rapid preparation times. The authors report the novel use of digitonin-treated rat hepatocytes, which provide such a system. This preparation, which is complete in <10 min, does not carry out cytosolic protein synthesis, but labels mitochondrial translation products at rates much higher than intact cells or isolated, in vitro labeled mitochondria. (Auth.)

  16. Mitochondrial Dynamics in Diabetic Cardiomyopathy

    Science.gov (United States)

    Galloway, Chad A.

    2015-01-01

    Abstract Significance: Cardiac function is energetically demanding, reliant on efficient well-coupled mitochondria to generate adenosine triphosphate and fulfill the cardiac demand. Predictably then, mitochondrial dysfunction is associated with cardiac pathologies, often related to metabolic disease, most commonly diabetes. Diabetic cardiomyopathy (DCM), characterized by decreased left ventricular function, arises independently of coronary artery disease and atherosclerosis. Dysregulation of Ca2+ handling, metabolic changes, and oxidative stress are observed in DCM, abnormalities reflected in alterations in mitochondrial energetics. Cardiac tissue from DCM patients also presents with altered mitochondrial morphology, suggesting a possible role of mitochondrial dynamics in its pathological progression. Recent Advances: Abnormal mitochondrial morphology is associated with pathologies across diverse tissues, suggesting that this highly regulated process is essential for proper cell maintenance and physiological homeostasis. Highly structured cardiac myofibers were hypothesized to limit alterations in mitochondrial morphology; however, recent work has identified morphological changes in cardiac tissue, specifically in DCM. Critical Issues: Mitochondrial dysfunction has been reported independently from observations of altered mitochondrial morphology in DCM. The temporal relationship and causative nature between functional and morphological changes of mitochondria in the establishment/progression of DCM is unclear. Future Directions: Altered mitochondrial energetics and morphology are not only causal for but also consequential to reactive oxygen species production, hence exacerbating oxidative damage through reciprocal amplification, which is integral to the progression of DCM. Therefore, targeting mitochondria for DCM will require better mechanistic characterization of morphological distortion and bioenergetic dysfunction. Antioxid. Redox Signal. 22, 1545–1562. PMID

  17. Muscle regeneration in mitochondrial myopathies

    DEFF Research Database (Denmark)

    Krag, T O; Hauerslev, S; Jeppesen, T D

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  18. Modification of Salmonella Lipopolysaccharides Prevents the Outer Membrane Penetration of Novobiocin

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, Thatyane M.; Martynowycz, Michael W.; Andreev, Konstantin; Kuzmenko, Ivan; Nikaido, Hiroshi; Gidalevitz, David

    2015-12-01

    Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate lipopolysaccharides from isogenic mutants of Salmonella sp., one lacking the modification, the other fully modified. These lipopolysaccharides were reconstituted asmonolayers at the air-water interface, and their properties, aswell as their interaction with a large lipophilic drug, novobiocin, was studied. X-ray reflectivity showed that the drug penetrated the monolayer of the unmodified lipopolysaccharides reaching the hydrophobic region,butwas prevented fromthis penetration intothemodified lipopolysaccharides.Results correlatewith behavior of bacterial cells, which become resistant to antibiotics after PhoPQ-regulated modifications. Grazing incidence x-ray diffraction showed that novobiocin produced a striking increase in crystalline coherence length, and the size of the near-crystalline domains.

  19. 大黄鱼三种病原弧菌外膜蛋白交叉保护性抗原筛选%Selection of cross-protective antigens from outer membrane proteins of three pathogenic vibrios isolated from infected large yellow croaker (Pseudosciaena crocea)

    Institute of Scientific and Technical Information of China (English)

    张崇文; 毛芝娟; 于涟

    2012-01-01

    弧菌是海水养殖环境中常见的条件性致病菌,弧菌病的暴发给水产养殖业造成了严重损失.鉴于水生动物尤其是鱼类弧菌病的发生常常是多种(血清型或亚种)弧菌的混合感染,筛选具有潜在的交叉保护性蛋白抗原,作为制备多价疫苗或联合疫苗的侯选成分具有重要意义.文中从患病大黄鱼中分离到8株弧菌,经生理生化和分子生物学鉴定分别为6株哈维氏弧菌Vibrio harveyi,1株溶藻弧菌Vibrio alginolyticus和1株副溶血弧菌Vibrio parahaemolyticus.选择典型的不同种的弧菌为代表,提取其外膜蛋白,经SDS-PAGE和Western blotting分析,确定它们大约在45 kDa、35 kDa、22 kDa处出现了3条共同的免疫印迹条带,表明它们很有可能含有共同的能够彼此交叉保护的抗原.利用双向电泳和免疫印迹相结合的方法,借助于MALDI-TOF-MS质谱分析技术,发现溶藻弧菌V.alginolyticus的一种功能未知的孔蛋白(Porin,GenBank Accession No.ZP_01260407)和副溶血弧菌V.parahaemolyticus的一种麦芽糖孔蛋白的前体蛋白(Maltoporin precursor,GenBank Accession No.NP_801154)能够和哈维氏弧菌V.harveyi全菌多抗产生免疫反应,表明这两种蛋白可以作为3种弧菌的交叉保护性抗原,以此制备的疫苗可望对3种弧菌的感染产生交叉保护作用.%Vibrios are universal conditioned-pathogenic bacteria in marine culture environment, and the outbreak of vibrio disease resulted in a serious damage to aquaculture. Considering that vibrio disease in aquatic species, especially fishes, usually originated from mixed infection of different species (serotypes or subspecies) of vibrios, it is important to select the potential cross-protective protein antigens as candidates of polyvalent or combined vaccines. In present research, several strains of vibrios were isolated from infected large yellow croaker (Pseudosciaena crocea) and subsequently identified as six strains of V. harveyi, one V

  20. Ca2+-mobilizing agonists increase mitochondrial ATP production to accelerate cytosolic Ca2+ removal: aberrations in human complex I deficiency.

    NARCIS (Netherlands)

    Visch, H.J.; Koopman, W.J.H.; Zeegers, D.; Emst-de Vries, S.E. van; Kuppeveld, F.J.M. van; Heuvel, L.W. van den; Smeitink, J.A.M.; Willems, P.H.G.M.

    2006-01-01

    Previously, we reported that both the bradykinin (Bk)-induced increase in mitochondrial ATP concentration ([ATP]M) and the rate of cytosolic Ca2+ removal are significantly decreased in skin fibroblasts from a patient with an isolated complex I deficiency. Here we demonstrate that the mitochondrial

  1. Dynamics of enhanced mitochondrial respiration in female compared with male rat cerebral arteries.

    Science.gov (United States)

    Rutkai, Ibolya; Dutta, Somhrita; Katakam, Prasad V; Busija, David W

    2015-11-01

    Mitochondrial respiration has never been directly examined in intact cerebral arteries. We tested the hypothesis that mitochondrial energetics of large cerebral arteries ex vivo are sex dependent. The Seahorse XFe24 analyzer was used to examine mitochondrial respiration in isolated cerebral arteries from adult male and female Sprague-Dawley rats. We examined the role of nitric oxide (NO) on mitochondrial respiration under basal conditions, using N(ω)-nitro-l-arginine methyl ester, and following pharmacological challenge using diazoxide (DZ), and also determined levels of mitochondrial and nonmitochondrial proteins using Western blot, and vascular diameter responses to DZ. The components of mitochondrial respiration including basal respiration, ATP production, proton leak, maximal respiration, and spare respiratory capacity were elevated in females compared with males, but increased in both male and female arteries in the presence of the NOS inhibitor. Although acute DZ treatment had little effect on mitochondrial respiration of male arteries, it decreased the respiration in female arteries. Levels of mitochondrial proteins in Complexes I-V and the voltage-dependent anion channel protein were elevated in female compared with male cerebral arteries. The DZ-induced vasodilation was greater in females than in males. Our findings show that substantial sex differences in mitochondrial respiratory dynamics exist in large cerebral arteries and may provide the mechanistic basis for observations that the female cerebral vasculature is more adaptable after injury. Copyright © 2015 the American Physiological Society.

  2. Effect of organic synthetic food colours on mitochondrial respiration.

    Science.gov (United States)

    Reyes, F G; Valim, M F; Vercesi, A E

    1996-01-01

    Eleven organic synthetic dyes, currently or formerly used as food colours in Brazil, were tested to determine their effect on mitochondrial respiration in mitochondria isolated from rat liver and kidney. The compounds tested were: Erythrosine, Ponceau 4R, Allura Red, Sunset yellow, Tartrazine, Amaranth, Brilliant Blue, Blue, Fast Red E, Orange GGN and Scarlet GN. All food colours tested inhibited mitochondrial respiration (State III respiration, uncoupled) supported either by alpha-ketoglutarate or succinate. This inhibition varied largely, e.g. from 100% to 16% for Erythrosine and Tartrazine respectively, at a concentration of 0.1 mg food colour per mitochondrial protein. Both rat liver and kidney mitochondria showed similar patterns of inhibition among the food colours tested. This effect was dose related and the concentration to give 50% inhibition was determined for some of the dyes. The xanthene dye Erythrosine, which showed the strongest effect, was selected for further investigation on mitochondria in vivo.

  3. Inheritance of the yeast mitochondrial genome

    DEFF Research Database (Denmark)

    Piskur, Jure

    1994-01-01

    Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast......Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast...

  4. Performance of the LHCb Outer Tracker

    CERN Document Server

    Arink, R; Bachmann, S.; Bagaturia, Y.; Band, H.; Bauer, Th.; Berkien, A.; Farber, Ch.; Bien, A.; Blouw, J.; Ceelie, L.; Coco, V.; Deckenhoff, M.; Deng, Z.; Dettori, F.; van Eijk, D.; Ekelhof, R.; Gersabeck, E.; Grillo, L.; Hulsbergen, W.D.; Karbach, T.M.; Koopman, R.; Kozlinskiy, A.; Langenbruch, Ch.; Lavrentyev, V.; Linn, Ch.; Merk, M.; Merkel, J.; Meissner, M.; Michalowski, J.; Morawski, P.; Nawrot, A.; Nedos, M.; Pellegrino, A.; Polok, G.; van Petten, O.; Rovekamp, J.; Schimmel, F.; Schuylenburg, H.; Schwemmer, R.; Seyfert, P.; Serra, N.; Sluijk, T.; Spaan, B.; Spelt, J.; Storaci, B.; Szczekowski, M.; Swientek, S.; Tolk, S.; Tuning, N.; Uwer, U.; Wiedner, D.; Witek, M.; Zeng, M.; Zwart, A.

    2014-01-01

    The LHCb Outer Tracker is a gaseous detector covering an area of 5x6 m2 with 12 double layers of straw tubes. The detector with its services are described together with the commissioning and calibration procedures. Based on data of the first LHC running period from 2010 to 2012, the performance of the readout electronics and the single hit resolution and efficiency are presented. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 um. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.

  5. The Outer Space as an Educational Motivation

    Science.gov (United States)

    Pérez-Pérez, Melquíades; Hernández-López, Montserrat

    2017-06-01

    STEAM is an educational approach to learning that uses Science, Technology, Engineering, the Arts and Mathematics as access points for guiding student inquiry, dialogue, and critical thinking. The end results are students who take thoughtful risks, engage in experiential learning, persist in problem-solving, embrace collaboration, and work through the creative process. The Outer Space is a window to the past and the future of our travel around the history of the Universe and can be used as a educational tool in primary and secondary education. This paper talks about the integration of the resources of European Space Agency, Space Awareness, Nuclio, Scientix and Schoolnet as motivation to integrate STEAM methodology in secondary education. Keywords: STEAM, outer space, motivation, methodology

  6. The Outer Banks of North Carolina

    Science.gov (United States)

    Dolan, Robert; Lins, Harry F.; Smith, Jodi Jones

    2016-12-27

    The Outer Banks of North Carolina are excellent examples of the nearly 300 barrier islands rimming the Atlantic and Gulf coasts of the United States. These low, sandy islands are among the most dynamic natural landscapes occupied by man. Beach sands move offshore, onshore, and along the shore in the direction of the prevailing longshore currents. In this way, sandy coasts continuously adjust to different tide, wave, and current conditions and to rising sea level that causes the islands to migrate landward.Despite such changes, barrier islands are of considerable environmental importance. The Outer Banks are home to diverse natural ecosystems that are adapted to the harsh coastal environment. Native species tend to be robust and many are specifically adapted to withstand salt spray, periodic saltwater flooding, and the islands’ well-drained sandy soil. The Outer Banks provide an important stopover for birds on the Atlantic flyway, and many species inhabit the islands year round. In addition, Outer Banks beaches provide an important nesting habitat for five endangered or threatened sea turtle species.European explorers discovered North Carolina’s barrier islands in the 16th century, although the islands were not permanently settled until the middle 17th century. By the early 19th century, shipbuilding and lumber industries were among the most successful, until forest resources were depleted. Commercial fishing eventually followed, and it expanded considerably after the Civil War. By the Great Depression, however, little industry existed on the Outer Banks. In response to the effects of a severe hurricane in 1933, the National Park Service and the Civilian Conservation Corps proposed a massive sand-fixation program to stabilize the moving sand and prevent storm waves from sweeping across the entire width of some sections of the islands. Between 1933 and 1940, this program constructed sand fencing on 185 kilometers (115 miles) of beach and planted grass seedlings

  7. Cryovolcanism in the outer solar system

    Science.gov (United States)

    Geissler, Paul E.

    2015-01-01

    Cryovolcanism is defined as the extrusion of liquids and vapors of materials that would be frozen solid at the planetary surface temperatures of the icy bodies of the outer solar system. Active cryovolcanism is now known to occur on Saturn's moon Enceladus and on Neptune's moon Triton and is suspected on Jupiter's moon Europa, while evidence for past cryovolcanic activity is widespread throughout the outer solar system. This chapter examines the mechanisms and manifestations of cryovolcanism, beginning with a review of the materials that make up these unusual ‘‘magmas’’ and the means by which they might erupt and concluding with a volcanologist's tour of the farthest reaches of the solar system.

  8. Protection of nuclear facilities against outer aggressions

    International Nuclear Information System (INIS)

    Aussourd, P.; Candes, P.; Le Quinio, R.

    1976-01-01

    The various types of outer aggressions envisaged in safety analysis for nuclear facilities are reviewed. These outer aggressions are classified as natural and non-natural phenomena, the latter depending on the human activities in the vicinity of nuclear sites. The principal natural phenomena able to constitute aggressions are atmospheric phenomena (strong winds, snow storms, hail, frosting mists), hydrologie phenomena such as tides, surges, flood, low waters, and geologic phenomena such as earthquakes. Artificial phenomena are concerned with aircraft crashes, projectiles, fire, possible ruptures of dams, and intentional human aggressions. The protection against intentional human aggressions is of two sorts: first, the possibility of access to the installations mostly sensitive to sabotage are to be prevented or reduced, secondly redundant circuits and functions must be separated for preventing their simultaneous destruction in the case when sabotage actors have reach the core of the facility [fr

  9. Outer crust of nonaccreting cold neutron stars

    International Nuclear Information System (INIS)

    Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen

    2006-01-01

    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars

  10. Boundary layers of the earth's outer magnetosphere

    Science.gov (United States)

    Eastman, T. E.; Frank, L. A.

    1984-01-01

    The magnetospheric boundary layer and the plasma-sheet boundary layer are the primary boundary layers of the earth's outer magnetosphere. Recent satellite observations indicate that they provide for more than 50 percent of the plasma and energy transport in the outer magnetosphere although they constitute less than 5 percent by volume. Relative to the energy density in the source regions, plasma in the magnetospheric boundary layer is predominantly deenergized whereas plasma in the plasma-sheet boundary layer has been accelerated. The reconnection hypothesis continues to provide a useful framework for comparing data sampled in the highly dynamic magnetospheric environment. Observations of 'flux transfer events' and other detailed features near the boundaries have been recently interpreted in terms of nonsteady-state reconnection. Alternative hypotheses are also being investigated. More work needs to be done, both in theory and observation, to determine whether reconnection actually occurs in the magnetosphere and, if so, whether it is important for overall magnetospheric dynamics.

  11. Boundary layers of the earth's outer magnetosphere

    International Nuclear Information System (INIS)

    Eastman, T.E.; Frank, L.A.

    1984-01-01

    The magnetospheric boundary layer and the plasma-sheet boundary layer are the primary boundary layers of the earth's outer magnetosphere. Recent satellite observations indicate that they provide for more than 50 percent of the plasma and energy transport in the outer magnetosphere although they constitute less than 5 percent by volume. Relative to the energy density in the source regions, plasma in the magnetospheric boundary layer is predominantly deenergized whereas plasma in the plasma-sheet boundary layer has been accelerated. The reconnection hypothesis continues to provide a useful framework for comparing data sampled in the highly dynamic magnetospheric environment. Observations of flux transfer events and other detailed features near the boundaries have been recently interpreted in terms of nonsteady-state reconnection. Alternative hypotheses are also being investigated. More work needs to be done, both in theory and observation, to determine whether reconnection actually occurs in the magnetosphere and, if so, whether it is important for overall magnetospheric dynamics. 30 references

  12. Differential Rotation within the Earth's Outer Core

    Science.gov (United States)

    Hide, R.; Boggs, D. H.; Dickey, J. O.

    1998-01-01

    Non-steady differential rotation drive by bouyancy forces within the Earth's liquid outer core (OC) plays a key role not only in the generation of the main geomagnetic field by the magnetohydrodynamic (MHD) dynamo process but also in the excitation of irregular fluctuations in the angular speed of rotation of the overlying solid mantle, as evidenced by changes in the length of the day (LOD) on decadal and longer timescales (1-8).

  13. Fluxgate magnetometers for outer planets exploration

    Science.gov (United States)

    Acuna, M. H.

    1974-01-01

    The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

  14. Outer Limits of Biotechnologies: A Jewish Perspective

    Directory of Open Access Journals (Sweden)

    John D. Loike

    2018-01-01

    Full Text Available A great deal of biomedical research focuses on new biotechnologies such as gene editing, stem cell biology, and reproductive medicine, which have created a scientific revolution. While the potential medical benefits of this research may be far-reaching, ethical issues related to non-medical applications of these technologies are demanding. We analyze, from a Jewish legal perspective, some of the ethical conundrums that society faces in pushing the outer limits in researching these new biotechnologies.

  15. Understanding mitochondrial myopathies: a review

    Directory of Open Access Journals (Sweden)

    Abhimanyu S. Ahuja

    2018-05-01

    Full Text Available Mitochondria are small, energy-producing structures vital to the energy needs of the body. Genetic mutations cause mitochondria to fail to produce the energy needed by cells and organs which can cause severe disease and death. These genetic mutations are likely to be in the mitochondrial DNA (mtDNA, or possibly in the nuclear DNA (nDNA. The goal of this review is to assess the current understanding of mitochondrial diseases. This review focuses on the pathology, causes, risk factors, symptoms, prevalence data, symptomatic treatments, and new research aimed at possible preventions and/or treatments of mitochondrial diseases. Mitochondrial myopathies are mitochondrial diseases that cause prominent muscular symptoms such as muscle weakness and usually present with a multitude of symptoms and can affect virtually all organ systems. There is no cure for these diseases as of today. Treatment is generally supportive and emphasizes symptom management. Mitochondrial diseases occur infrequently and hence research funding levels tend to be low in comparison with more common diseases. On the positive side, quite a few genetic defects responsible for mitochondrial diseases have been identified, which are in turn being used to investigate potential treatments. Speech therapy, physical therapy, and respiratory therapy have been used in mitochondrial diseases with variable results. These therapies are not curative and at best help with maintaining a patient’s current abilities to move and function.

  16. Effect of the antitumoral alkylating agent 3-bromopyruvate on mitochondrial respiration: role of mitochondrially bound hexokinase.

    Science.gov (United States)

    Rodrigues-Ferreira, Clara; da Silva, Ana Paula Pereira; Galina, Antonio

    2012-02-01

    The alkylating agent 3-Bromopyruvate (3-BrPA) has been used as an anti-tumoral drug due to its anti-proliferative property in hepatomas cells. This propriety is believed to disturb glycolysis and respiration, which leads to a decreased rate of ATP synthesis. In this study, we evaluated the effects of the alkylating agent 3-BrPA on the respiratory states and the metabolic steps of the mitochondria of mice liver, brain and in human hepatocarcinoma cell line HepG2. The mitochondrial membrane potential (ΔΨ(m)), O(2) consumption and dehydrogenase activities were rapidly dissipated/or inhibited by 3-BrPA in respiration medium containing ADP and succinate as respiratory substrate. 3-BrPA inhibition was reverted by reduced glutathione (GSH). Respiration induced by yeast soluble hexokinase (HK) was rapidly inhibited by 3-BrPA. Similar results were observed using mice brain mitochondria that present HK naturally bound to the outer mitochondrial membrane. When the adenine nucleotide transporter (ANT) was blocked by the carboxyatractiloside, the 3-BrPA effect was significantly delayed. In permeabilized human hepatoma HepG2 cells that present HK type II bound to mitochondria (mt-HK II), the inhibiting effect occurred faster when the endogenous HK activity was activated by 2-deoxyglucose (2-DOG). Inhibition of mt-HK II by glucose-6-phosphate retards the mitochondria to react with 3-BrPA. The HK activities recovered in HepG2 cells treated or not with 3-BrPA were practically the same. These results suggest that mitochondrially bound HK supporting the ADP/ATP exchange activity levels facilitates the 3-BrPA inhibition reaction in tumors mitochondria by a proton motive force-dependent dynamic equilibrium between sensitive and less sensitive SDH in the electron transport system.

  17. Mitochondrial DNA repair and aging

    International Nuclear Information System (INIS)

    Mandavilli, Bhaskar S.; Santos, Janine H.; Van Houten, Bennett

    2002-01-01

    The mitochondrial electron transport chain plays an important role in energy production in aerobic organisms and is also a significant source of reactive oxygen species that damage DNA, RNA and proteins in the cell. Oxidative damage to the mitochondrial DNA is implicated in various degenerative diseases, cancer and aging. The importance of mitochondrial ROS in age-related degenerative diseases is further strengthened by studies using animal models, Caenorhabditis elegans, Drosophila and yeast. Research in the last several years shows that mitochondrial DNA is more susceptible to various carcinogens and ROS when compared to nuclear DNA. DNA damage in mammalian mitochondria is repaired by base excision repair (BER). Studies have shown that mitochondria contain all the enzymes required for BER. Mitochondrial DNA damage, if not repaired, leads to disruption of electron transport chain and production of more ROS. This vicious cycle of ROS production and mtDNA damage ultimately leads to energy depletion in the cell and apoptosis

  18. Mitochondrial Dysfunction in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    P. C. Keane

    2011-01-01

    Full Text Available Parkinson's disease (PD is a progressive, neurodegenerative condition that has increasingly been linked with mitochondrial dysfunction and inhibition of the electron transport chain. This inhibition leads to the generation of reactive oxygen species and depletion of cellular energy levels, which can consequently cause cellular damage and death mediated by oxidative stress and excitotoxicity. A number of genes that have been shown to have links with inherited forms of PD encode mitochondrial proteins or proteins implicated in mitochondrial dysfunction, supporting the central involvement of mitochondria in PD. This involvement is corroborated by reports that environmental toxins that inhibit the mitochondrial respiratory chain have been shown to be associated with PD. This paper aims to illustrate the considerable body of evidence linking mitochondrial dysfunction with neuronal cell death in the substantia nigra pars compacta (SNpc of PD patients and to highlight the important need for further research in this area.

  19. Mitochondrial DNA repair and aging

    Energy Technology Data Exchange (ETDEWEB)

    Mandavilli, Bhaskar S.; Santos, Janine H.; Van Houten, Bennett

    2002-11-30

    The mitochondrial electron transport chain plays an important role in energy production in aerobic organisms and is also a significant source of reactive oxygen species that damage DNA, RNA and proteins in the cell. Oxidative damage to the mitochondrial DNA is implicated in various degenerative diseases, cancer and aging. The importance of mitochondrial ROS in age-related degenerative diseases is further strengthened by studies using animal models, Caenorhabditis elegans, Drosophila and yeast. Research in the last several years shows that mitochondrial DNA is more susceptible to various carcinogens and ROS when compared to nuclear DNA. DNA damage in mammalian mitochondria is repaired by base excision repair (BER). Studies have shown that mitochondria contain all the enzymes required for BER. Mitochondrial DNA damage, if not repaired, leads to disruption of electron transport chain and production of more ROS. This vicious cycle of ROS production and mtDNA damage ultimately leads to energy depletion in the cell and apoptosis.

  20. Endocrine disorders in mitochondrial disease.

    Science.gov (United States)

    Schaefer, Andrew M; Walker, Mark; Turnbull, Douglass M; Taylor, Robert W

    2013-10-15

    Endocrine dysfunction in mitochondrial disease is commonplace, but predominantly restricted to disease of the endocrine pancreas resulting in diabetes mellitus. Other endocrine manifestations occur, but are relatively rare by comparison. In mitochondrial disease, neuromuscular symptoms often dominate the clinical phenotype, but it is of paramount importance to appreciate the multi-system nature of the disease, of which endocrine dysfunction may be a part. The numerous phenotypes attributable to pathogenic mutations in both the mitochondrial (mtDNA) and nuclear DNA creates a complex and heterogeneous catalogue of disease which can be difficult to navigate for novices and experts alike. In this article we provide an overview of the endocrine disorders associated with mitochondrial disease, the way in which the underlying mitochondrial disorder influences the clinical presentation, and how these factors influence subsequent management. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  1. MITOCHONDRIAL DYNAMICS IN PRE- AND POSTPUBERTAL PIG OOCYTES BEFORE AND AFTER IN VITRO MATURATION

    DEFF Research Database (Denmark)

    Pedersen, H. S.; Løvendahl, P.; Nikolaisen, N. K.

    2013-01-01

    Oocytes from prepubertal (PRE) or postpubertal (POST) pigs are used in, for example, somatic cell nuclear transfer and in vitro fertilization. Here we describe mitochondrial dynamics in pig oocytes of different sizes before and after in vitro maturation (IVM), isolated from PRE or POST animals....... In PRE oocytes, inside-zona pellucida diameter was measured before and after IVM (μm; small: ≤110, medium: >110, large: ≥120) and used for evaluation of (1) mitochondrial numbers before maturation and (2) mitochondrial morphology and location before and after maturation in comparison with POST oocytes....... Oocytes were processed for transmission electron microscopy (Acta Anat. 129:12). For assessment of mitochondrial numbers, paired dissector sections were collected at uniform intervals throughout the oocyte, and in each set of dissector sections a known area fraction was sampled for mitochondrial counting...

  2. Insulin increases phosphorylation of mitochondrial proteins in human skeletal muscle in vivo

    DEFF Research Database (Denmark)

    Zhao, Xiaolu; Bak, Steffen; Pedersen, Andreas James Thestrup

    2014-01-01

    , we investigated the effect of insulin on the phosphorylation of mitochondrial proteins in human skeletal muscle in vivo. Using a combination of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC−MS/MS, we compared the phosphoproteomes of isolated mitochondria from skeletal muscle samples...... obtained from healthy individuals before and after 4 h of insulin infusion. In total, we identified 207 phosphorylation sites in 95 mitochondrial proteins. Of these phosphorylation sites, 45% were identified in both basal and insulin-stimulated samples. Insulin caused a 2-fold increase in the number...... of different mitochondrial phosphopeptides (87 ± 7 vs 40 ± 7, p = 0.015) and phosphoproteins (46 ± 2 vs 26 ± 3, p = 0.005) identified in each mitochondrial preparation. Almost half of the mitochondrial phosphorylation sites (n = 94) were exclusively identified in the insulin-stimulated state and included...

  3. Unchanged mitochondrial phenotype, but accumulation of lipids in the myometrium in obese pregnant women

    DEFF Research Database (Denmark)

    Gam, Christiane Marie Bourgin Folke; Larsen, Lea Hüche; Mortensen, Ole Hartvig

    2017-01-01

    myometrial mitochondrial capacity or quantity could contribute as a pathophysiological mechanism to labour dystocia. Data did not support reduced myometrial mitochondrial capacity or quantity in the myometrium at term in obese women, but a reduced myocyte density with increased triglyceride content...... to reduced mitochondrial capacity or quantity, could be a possible mechanism leading to reduced efficiency of uterine contractility during labour. In the present study of 36 women having an elective Caesarean section at term, obesity did not change mitochondrial phenotype in the myometrial myocyte obtained...... in obese women. In conclusion no indication of myometrial mitochondrial dysfunction in the isolated state was found, but the observed increase of lipid content might play a role in the pathophysiological mechanisms behind labour dystocia in obese women....

  4. Mitochondrial function in human skeletal muscle following high-altitude exposure

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Boushel, Robert; Wright-Paradis, Cynthia

    2013-01-01

    Studies regarding mitochondrial modifications in human skeletal muscle following acclimatization to high altitude are conflicting, and these inconsistencies may be due to the prevalence of representing mitochondrial function through static and isolated measurements of specific mitochondrial...... characteristics. The aim of this study, therefore, was to investigate mitochondrial function in response to high-altitude acclimatization through measurements of respiratory control in the vastus lateralis muscle. Skeletal muscle biopsies were obtained from 10 lowland natives prior to and again after a total of 9......-11 days of exposure to 4559 m. High-resolution respirometry was performed on the muscle samples to compare respiratory chain function and respiratory capacities. Respirometric analysis revealed that mitochondrial function was largely unaffected, because high-altitude exposure did not affect the capacity...

  5. Oxidative stress and mitochondrial impairment can be separated from lipofuscin accumulation in aged human skeletal muscle

    DEFF Research Database (Denmark)

    Hütter, Eveline; Skovbro, Mette; Lener, Barbara

    2007-01-01

    According to the free radical theory of aging, reactive oxygen species (ROS) act as a driving force of the aging process, and it is generally believed that mitochondrial dysfunction is a major source of increased oxidative stress in tissues with high content of mitochondria, such as muscle or brain....... However, recent experiments in mouse models of premature aging have questioned the role of mitochondrial ROS production in premature aging. To address the role of mitochondrial impairment and ROS production for aging in human muscles, we have analyzed mitochondrial properties in muscle fibres isolated...... from the vastus lateralis of young and elderly donors. Mitochondrial respiratory functions were addressed by high-resolution respirometry, and ROS production was analyzed by in situ staining with the redox-sensitive dye dihydroethidium. We found that aged human skeletal muscles contain fully functional...

  6. Direct Regulation of Mitochondrial RNA Synthesis by Thyroid Hormone

    Science.gov (United States)

    Enríquez, José A.; Fernández-Silva, Patricio; Garrido-Pérez, Nuria; López-Pérez, Manuel J.; Pérez-Martos, Acisclo; Montoya, Julio

    1999-01-01

    We have analyzed the influence of in vivo treatment and in vitro addition of thyroid hormone on in organello mitochondrial DNA (mtDNA) transcription and, in parallel, on the in organello footprinting patterns at the mtDNA regions involved in the regulation of transcription. We found that thyroid hormone modulates mitochondrial RNA levels and the mRNA/rRNA ratio by influencing the transcriptional rate. In addition, we found conspicuous differences between the mtDNA dimethyl sulfate footprinting patterns of mitochondria derived from euthyroid and hypothyroid rats at the transcription initiation sites but not at the mitochondrial transcription termination factor (mTERF) binding region. Furthermore, direct addition of thyroid hormone to the incubation medium of mitochondria isolated from hypothyroid rats restored the mRNA/rRNA ratio found in euthyroid rats as well as the mtDNA footprinting patterns at the transcription initiation area. Therefore, we conclude that the regulatory effect of thyroid hormone on mitochondrial transcription is partially exerted by a direct influence of the hormone on the mitochondrial transcription machinery. Particularly, the influence on the mRNA/rRNA ratio is achieved by selective modulation of the alternative H-strand transcription initiation sites and does not require the previous activation of nuclear genes. These results provide the first functional demonstration that regulatory signals, such as thyroid hormone, that modify the expression of nuclear genes can also act as primary signals for the transcriptional apparatus of mitochondria. PMID:9858589

  7. mtDNA depletion myopathy: elucidation of the tissue specificity in the mitochondrial thymidine kinase (TK2) deficiency.

    Science.gov (United States)

    Saada, Ann; Shaag, Avraham; Elpeleg, Orly

    2003-05-01

    Decreased mitochondrial thymidine kinase (TK2) activity is associated with mitochondrial DNA (mtDNA) depletion and respiratory chain dysfunction and is manifested by isolated, fatal skeletal myopathy. Other tissues such as liver, brain, heart, and skin remain unaffected throughout the patients' life. In order to elucidate the mechanism of tissue specificity in the disease we have investigated the expression of the mitochondrial deoxynucleotide carrier, the mtDNA content and the activity of TK2 in mitochondria of various tissues. Our results suggest that low basal TK2 activity combined with a high requirement for mitochondrial encoded proteins in muscle predispose this tissue to the devastating effect of TK2 deficiency.

  8. 75 FR 1076 - Outer Continental Shelf Civil Penalties

    Science.gov (United States)

    2010-01-08

    ... initiate civil penalty proceedings; however, violations that cause injury, death, or environmental damage... DEPARTMENT OF THE INTERIOR Minerals Management Service Outer Continental Shelf Civil Penalties... daily civil penalty assessment. SUMMARY: The Outer Continental Shelf Lands Act requires the MMS to...

  9. Issues concerning outer space investments in international law ...

    African Journals Online (AJOL)

    Issues concerning outer space investments in international law. ... Recent improvements in technology have in essence increased the viability of outer space as the next frontier for international investment and development. In addition to ... Key words: Outer Space, Investments, International Law, International Space Station ...

  10. A highly rearranged mitochondrial genome in Nycteria parasites (Haemosporidia) from bats

    OpenAIRE

    Karadjian , Gregory; Hassanin , Alexandre; Saintpierre , Benjamin; Gembu Tungaluna , Guy-Crispin; Ariey , Frederic; Ayala , Francisco J.; Landau , Irene; Duval , Linda

    2016-01-01

    International audience; Haemosporidia parasites have mostly and abundantly been described using mitochondrial genes, and in particular cytochrome b (cytb). Failure to amplify the mitochondrial cytb gene of Nycteria parasites isolated from Nycteridae bats has been recently reported. Bats are hosts to a diverse and profuse array of Haemosporidia parasites that remain largely unstudied. There is a need to obtain more molecular data from chiropteran parasites. Such data would help to better under...

  11. Mitochondrial Genomes of Kinorhyncha: trnM Duplication and New Gene Orders within Animals

    OpenAIRE

    Popova, Olga V.; Mikhailov, Kirill V.; Nikitin, Mikhail A.; Logacheva, Maria D.; Penin, Aleksey A.; Muntyan, Maria S.; Kedrova, Olga S.; Petrov, Nikolai B.; Panchin, Yuri V.; Aleoshin, Vladimir V.

    2016-01-01

    Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha-an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the earl...

  12. Preliminary crystallographic studies of yeast mitochondrial peripheral membrane protein Tim44p

    Energy Technology Data Exchange (ETDEWEB)

    Josyula, Ratnakar [Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States); Jin, Zhongmin [SER-CAT, APS, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); McCombs, Deborah; DeLucas, Lawrence [Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States); Sha, Bingdong, E-mail: bdsha@uab.edu [Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham (United States)

    2006-02-01

    Tim44p is an essential mitochondrial peripheral membrane protein. To investigate the mechanism by which Tim44p functions in the TIM23 translocon to deliver the mitochondrial protein precursors, the yeast Tim44p has been crystallized. Protein translocations across mitochondrial membranes play critical roles in mitochondrion biogenesis. Protein transport from the cell cytosol to the mitochondrial matrix is carried out by the translocase of the outer membrane (TOM) complex and the translocase of the inner membrane (TIM) complexes. Tim44p is an essential mitochondrial peripheral membrane protein and a major component of the TIM23 translocon. To investigate the mechanism by which Tim44p functions in the TIM23 translocon to deliver the mitochondrial protein precursors, the yeast Tim44p was crystallized. The crystals diffract to 3.2 Å using a synchrotron X-ray source and belong to space group P6{sub 3}22, with unit-cell parameters a = 124.25, c = 77.83 Å. There is one Tim44p molecule in one asymmetric unit, which corresponds to a solvent content of approximately 43%. Structure determination by MAD methods is under way.

  13. Lophotrochozoan mitochondrial genomes

    Energy Technology Data Exchange (ETDEWEB)

    Valles, Yvonne; Boore, Jeffrey L.

    2005-10-01

    Progress in both molecular techniques and phylogeneticmethods has challenged many of the interpretations of traditionaltaxonomy. One example is in the recognition of the animal superphylumLophotrochozoa (annelids, mollusks, echiurans, platyhelminthes,brachiopods, and other phyla), although the relationships within thisgroup and the inclusion of some phyla remain uncertain. While much ofthis progress in phylogenetic reconstruction has been based on comparingsingle gene sequences, we are beginning to see the potential of comparinglarge-scale features of genomes, such as the relative order of genes.Even though tremendous progress is being made on the sequencedetermination of whole nuclear genomes, the dataset of choice forgenome-level characters for many animals across a broad taxonomic rangeremains mitochondrial genomes. We review here what is known aboutmitochondrial genomes of the lophotrochozoans and discuss the promisethat this dataset will enable insight into theirrelationships.

  14. Complete mitochondrial genome of freshwater shark Wallago attu (Bloch & Schneider) from Indus River Sindh, Pakistan.

    Science.gov (United States)

    Laghari, Muhammad Younis; Lashari, Punhal; Xu, Peng; Zhao, Zixia; Jiang, Li; Narejo, Naeem Tariq; Xin, Baoping; Sun, Xiaowen; Zhang, Yan

    2016-01-01

    Complete mitochondrial genome of fresh water giant catfish, Wallago attu, was isolated by LA PCR (TakaRa LAtaq, Dalian, China); and sequenced by Sanger's method to obtain the complete mitochondrial genome. The complete mitogenome was 15,639 bp in length and contains 13 typical vertebrate protein-coding genes, 2 rRNA and 22 tRNA genes. The whole genome base composition was estimated to be 31.17% A, 28.15% C, 15.55% G and 25.12% T. The complete mitochondrial genome of catfish, W. attu, provides the fundamental tools for genetic breeding.

  15. Complete mitochondrial genome of the Freshwater Catfish Rita rita (Siluriformes, Bagridae).

    Science.gov (United States)

    Lashari, Punhal; Laghari, Muhammad Younis; Xu, Peng; Zhao, Zixia; Jiang, Li; Narejo, Naeem Tariq; Deng, Yulin; Sun, Xiaowen; Zhang, Yan

    2015-01-01

    The complete mitochondrial genome of Catfish, Rita rita, was isolated by LA PCR (TakaRa LAtaq, Dalian, China); and sequenced by Sanger's method to obtain the complete mitochondrial genome, which is listed Critically Endangered and Red Listed species. The complete mitogenome was 16,449 bp in length and contains 13 typical vertebrate protein-coding genes, 2 rRNA and 22 tRNA genes. The whole genome base composition was estimated to be 33.40% A, 27.43% C, 14.26% G and 24.89% T. The complete mitochondrial genome of catfish, Rita rita provides the basis for genetic breeding and conservation studies.

  16. Dark matter in the outer solar system

    Science.gov (United States)

    Owen, T.; Cruikshank, D.; De Bergh, C.; Geballe, T.

    1994-01-01

    There are now a large number of small bodies in the outer solar system that are known to be covered with dark material. Attempts to identify that material have been thwarted by the absence of discrete absorption features in the reflection spectra of these planetesimals. An absorption at 2.2 micrometers that appeared to be present in several objects has not been confirmed by new observations. Three absorptions in the spectrum of the unusually red planetesimal 5145 Pholus are well-established, but their identity remains a mystery.

  17. Inner and Outer Life at Work

    DEFF Research Database (Denmark)

    Lundgaard Andersen, Linda

    2012-01-01

    involving people to people interactions offered by psychodynamic theories and methods take up a pivotal position. Psychoanalytic organisational and work life research explores how work, organisations and individuals are affected by psychic dynamics, the influence of the unconscious in the forms of human...... development and interaction situated in a societal context. Based on this substantial work I draw upon two influential psychoanalytical positions—the British Tavistock position and German psychoanalytic social psychology in order to situate and identify how to understand the inner and outer life at work...

  18. The urgency of outer territories anthropology

    Directory of Open Access Journals (Sweden)

    Miloš Milenković

    2016-02-01

    Full Text Available In the context of transforming a part of Serbian anthropology into social theoretic management of identity, I suggest both comparative historiographic and ethnographic learning from societies with similar post-colonial experience, with the aim to include the discipline into an urgent defense of Serbia and Belgrade from further ethno-profiteering interests of elites in/from outer territories, left over on the ruins of our ill judged, resource incompatible, exaggerated or immoral twentieth century adventures. Serbian anthropology, written by anthropologists to whom Serbia and Belgrade are "homeland" by origin or civilized choice, should play the key role in the defense of Serbian citizens from the interest of elites in/from the outer "homelands", particularly by revealing the processes for which it is, as a discipline, most expert at – the professionalization of ethnicity, interactive and hybrid nature of identity, instrumental nature of tradition and the identity politics in general. Having in mind the latest attempt, a particularly successful one, conducted by the end of the 20th and the beginning of the 21st century that the lives, health, well-being, dignity and future of persons born in and loyal to the interest of Serbia and Belgrade, in large scale, thoroughly and long term be sacrificed and dedicated to the interests of ethno-profiteering elites in/from outer territories, in this article I point to the possibility to, along with the comparative learning from the above mentioned post-colonial experiences, delicate experiences of urgent anthropology be applied as well as the rich tradition of collective research. This text analyzes the results of first such research, that represenst the initial, praiseworthy and a brave step in the wise striving to engage social sciences and humanities in a search of expert and not mythical/daily-political solutions of the key problem of the Serbian nation – that of how to settle the interests of the

  19. The potato tuber mitochondrial proteome

    DEFF Research Database (Denmark)

    Møller, Ian Max; Salvato, Fernanda; Havelund, Jesper

    We are testing the hypothesis that oxidized peptides are released from stressed mitochondria and contribute to retrograde signalling (Møller IM & Sweetlove LJ 2010 Trends Plant Sci 15, 370-374). However, there is a large gap between the number of experimentally verified mitochondrial proteins (~450......) and in silico-predicted mitochondrial proteins (2000-3000). Thus, before starting to look for oxidized peptides, we wanted to expand the current compendium of plant mitochondrial proteins while obtaining what could be termed the "baseline proteome" from our model organelle, the potato tuber mitochondrion. Its...

  20. Obesity augments the age-induced increase in mitochondrial capacity for H(2) O(2) release in Zucker fatty rats

    DEFF Research Database (Denmark)

    Hey-Mogensen, Martin; Jeppesen, Jacob; Madsen, K

    2012-01-01

    determined and related to citrate synthase activity to determine intrinsic mitochondrial function. Mitochondrial-specific super-oxide dismuthase (MnSOD) protein content was determined in isolated mitochondria and muscle homogenate. Catalase protein content was determined in muscle homogenate. Results: Young...... was associated with increased mitochondrial hydrogenperoxide release. MnSOD tended to be higher in the obese strain in the isolated mitochondria. Regardless of age, catalase protein content was significantly lower in the obese rats. Conclusions: This study shows that the augmented increase in obesity and insulin...

  1. Mitochondrial Bioenergetics During Ischemia and Reperfusion.

    Science.gov (United States)

    Consolini, Alicia E; Ragone, María I; Bonazzola, Patricia; Colareda, Germán A

    2017-01-01

    During ischemia and reperfusion (I/R) mitochondria suffer a deficiency to supply the cardiomyocyte with chemical energy, but also contribute to the cytosolic ionic alterations especially of Ca 2+ . Their free calcium concentration ([Ca 2+ ]m) mainly depends on mitochondrial entrance through the uniporter (UCam) and extrusion in exchange with Na + (mNCX) driven by the electrochemical gradient (ΔΨm). Cardiac energetic is frequently estimated by the oxygen consumption, which determines metabolism coupled to ATP production and to the maintaining of ΔΨm. Nevertheless, a better estimation of heart energy consumption is the total heat release associated to ATP hydrolysis, metabolism, and binding reactions, which is measurable either in the presence or the absence of oxygenation or perfusion. Consequently, a mechano-calorimetrical approach on isolated hearts gives a tool to evaluate muscle economy. The mitochondrial role during I/R depends on the injury degree. We investigated the role of the mitochondrial Ca 2+ transporters in the energetic of hearts stunned by a model of no-flow I/R in rat hearts. This chapter explores an integrated view of previous and new results which give evidences to the mitochondrial role in cardiac stunning by ischemia o hypoxia, and the influence of thyroid alterations and cardioprotective strategies, such as cardioplegic solutions (high K-low Ca, pyruvate) and the phytoestrogen genistein in both sex. Rat ventricles were perfused in a flow-calorimeter at either 30 °C or 37 °C to continuously measure the left ventricular pressure (LVP) and total heat rate (Ht). A pharmacological treatment was done before exposing to no-flow I and R. The post-ischemic contractile (PICR as %) and energetical (Ht) recovery and muscle economy (Eco: P/Ht) were determined during stunning. The functional interaction between mitochondria (Mit) and sarcoplasmic reticulum (SR) was evaluated with selective mitochondrial inhibitors in hearts reperfused with Krebs-10 m

  2. Characterization of canine mitochondrial protein expression in natural and induced forms of idiopathic dilated cardiomyopathy.

    Science.gov (United States)

    Lopes, Rosana; Solter, Philip F; Sisson, D David; Oyama, Mark A; Prosek, Robert

    2006-06-01

    To map canine mitochondrial proteins and identify qualitative and quantitative differences in heart mitochondrial protein expression between healthy dogs and dogs with naturally occurring and induced dilated cardiomyopathy (DCM). Left ventricle samples were obtained from 7 healthy dogs, 7 Doberman Pinschers with naturally occurring DCM, and 7 dogs with induced DCM. Fresh and frozen mitochondrial fractions were isolated from the left ventricular free wall and analyzed by 2-dimensional electrophoresis. Protein spots that increased or decreased in density by >or= 2-fold between groups were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or quadrupole selecting, quadrupole collision cell, time-of-flight mass spectrometry. Within narrow pH gradients of control canine heart mitochondrial samples, a total of 1,528 protein spots were revealed. Forty subunits of heart mitochondrial proteins that differ significantly from control tissues were altered in tissue specimens from dogs with naturally occurring and induced forms of DCM. The most affected heart mitochondrial proteins in both groups were those of oxidative phosphorylation (55%). Upregulation of manganese superoxide dismutase was suggestive of heart oxidative injury in tissue specimens from dogs with both forms of DCM. Evidence of apoptosis was associated with overexpression of the heart mitochondrial voltage-dependent anion channel-2 protein and endonuclease G in tissue specimens from dogs with induced DCM. Alterations of heart mitochondrial proteins related to oxidative phosphorylation dysfunction were more prevalent in tissue specimens from dogs with induced or naturally occurring DCM, compared with those of control dogs.

  3. Strain specific variation of outer membrane proteins of wild Yersinia pestis strains subjected to different growth temperatures

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme Coutinho Abath

    1990-03-01

    Full Text Available Three Yersinia pestis strains isolated from humans and one laboratory strain (EV76 were grown in rich media at 28§C and 37§C and their outer membrane protein composition compared by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-Page. Several proteins with molecular weights ranging from 34 kDa to 7 kDa were observed to change in relative abundance in samples grown at different temperatures. At least seven Y. pestis outer membrane proteins showed a temperature-dependent and strain-specific behaviour. Some differences between the outer membrane proteins of full-pathogenic wild isolates and the EV76 strain could aldso be detected and the relevance of this finding on the use of laboratory strains as a reference to the study of Y. pestis biological properties is discuted.

  4. Decidual cell polyploidization necessitates mitochondrial activity.

    Directory of Open Access Journals (Sweden)

    Xinghong Ma

    Full Text Available Cellular polyploidy has been widely reported in nature, yet its developmental mechanism and function remain poorly understood. In the present study, to better define the aspects of decidual cell polyploidy, we isolated pure polyploid and non-polyploid decidual cell populations from the in vivo decidual bed. Three independent RNA pools prepared for each population were then subjected to the Affymetrix gene chip analysis for the whole mouse genome transcripts. Our data revealed up-regulation of 1015 genes and down-regulation of 1207 genes in the polyploid populations, as compared to the non-polyploid group. Comparative RT-PCR and in situ hybridization results indeed confirmed differential expressional regulation of several genes between the two populations. Based on functional enrichment analyses, up-regulated polyploidy genes appeared to implicate several functions, which primarily include cell/nuclear division, ATP binding, metabolic process, and mitochondrial activity, whereas that of down-regulated genes primarily included apoptosis and immune processes. Further analyses of genes that are related to mitochondria and bi-nucleation showed differential and regional expression within the decidual bed, consistent with the pattern of polyploidy. Consistently, studies revealed a marked induction of mitochondrial mass and ATP production in polyploid cells. The inhibition of mitochondrial activity by various pharmacological inhibitors, as well as by gene-specific targeting using siRNA-mediated technology showed a dramatic attenuation of polyploidy and bi-nucleation development during in vitro stromal cell decidualization, suggesting mitochondria play a major role in positive regulation of decidual cell polyploidization. Collectively, analyses of unique polyploidy markers and molecular signaling networks may be useful to further characterize functional aspects of decidual cell polyploidy at the site of implantation.

  5. Interspecific Comparison and annotation of two complete mitochondrial genome sequences from the plant pathogenic fungus Mycosphaerella graminicola

    Energy Technology Data Exchange (ETDEWEB)

    Millenbaugh, Bonnie A; Pangilinan, Jasmyn L.; Torriani, Stefano F.F.; Goodwin, Stephen B.; Kema, Gert H.J.; McDonald, Bruce A.

    2007-12-07

    The mitochondrial genomes of two isolates of the wheat pathogen Mycosphaerella graminicola were sequenced completely and compared to identify polymorphic regions. This organism is of interest because it is phylogenetically distant from other fungi with sequenced mitochondrial genomes and it has shown discordant patterns of nuclear and mitochondrial diversity. The mitochondrial genome of M. graminicola is a circular molecule of approximately 43,960 bp containing the typical genes coding for 14 proteins related to oxidative phosphorylation, one RNA polymerase, two rRNA genes and a set of 27 tRNAs. The mitochondrial DNA of M. graminicola lacks the gene encoding the putative ribosomal protein (rps5-like), commonly found in fungal mitochondrial genomes. Most of the tRNA genes were clustered with a gene order conserved with many other ascomycetes. A sample of thirty-five additional strains representing the known global mt diversity was partially sequenced to measure overall mitochondrial variability within the species. Little variation was found, confirming previous RFLP-based findings of low mitochondrial diversity. The mitochondrial sequence of M. graminicola is the first reported from the family Mycosphaerellaceae or the order Capnodiales. The sequence also provides a tool to better understand the development of fungicide resistance and the conflicting pattern of high nuclear and low mitochondrial diversity in global populations of this fungus.

  6. Heating of the outer solar atmosphere

    International Nuclear Information System (INIS)

    Parker, E.N.

    1983-01-01

    The author discusses the idea that there must be a source of magnetic fields somewhere below the solar surface. He starts by considering present day ideas about the sun's internal structure. The sun has a radius of approximately 700,000 km, of which the outer 100,000 km or so is the convective zone, according to mixing-length models. The dynamo is believed to operate in the convective zone, across which there may be a 5-10% variation in the angular velocity. There are the stretched east-west fields similar to the ones in the earth's core. Associated with these are poloidal fields which contribute to a net dipole moment of the sun and are generated by a dynamo. The author shows that essentially no magnetic field configuration has an equilibrium; they dissipate quickly in spite of the high conductivity in fluid motions and heating. This is probably the major part of the heating of the sun's outer atmosphere. (Auth.)

  7. Cosmics in the LHCb Outer Tracker

    CERN Document Server

    Aaij, Roel

    2010-01-01

    The LHCb experiment at the Large Hadron Collider studies the decay of B mesons to test the description of CP violation in the Standard Model and to search for new physics. The decay $B_s \\to \\mu^+ \\mu^-$ has been identified as very promising in the search for new physics. An excellent invariant mass resolution is required to suppress backgrounds to this decay. This in turn requires a momentum resolution of dp/p = 0.4%. The Outer Tracker is part of the LHCb tracking system and has been commissioned with cosmic muons. The noise in the Outer Tracker is shown to be less than 0.05%. To use drift time information in the reconstruction of cosmic tracks, the event time must be known. Four methods to obtain the event time are studied and compared. It is shown that the event time can be obtained with a resolution better than 2.6 ns. Using drift time information, tracks are reconstructed with a resolution of 344 $\\mu$m. Knowledge of the event time enables the calibration of electronic time offsets and the r(t)– relati...

  8. Gamma rays from pulsar outer gaps

    International Nuclear Information System (INIS)

    Chiang, J.; Romani, R.W.; Cheng Ho

    1993-01-01

    We describe a gamma ray pulsar code which computes the high energy photon emissivities from vacuum gaps in the outer magnetosphere, after the model outlined by Cheng, Ho and Ruderman (1986) and Ho (1989). Pair-production due to photon-photon interactions and radiation processes including curvature, synchrotron and inverse Compton processes are computed with an iterative scheme which converges to self-consistent photon and particle distributions for a sampling of locations in the outer magnetosphere. We follow the photons from these distributions as they propagate through the pulsar magnetosphere toward a distant observer. We include the effects of relativistic aberration, time-of-flight delays and reabsorption by photon-photon pair-production to determine an intensity map of the high energy pulsar emission on the sky. Using data from radio and optical observations to constrain the geometry of the magnetosphere as well as the possible observer viewing angles, we derive light curves and phase dependent spectra which can be directly compared to data from the Compton Observatory. Observations for Crab, Vela and the recently identified gamma ray pulsars Geminga, PSR1706-44 aNd PSR 1509-58 will provide important tests of our model calculations, help us to improve our picture of the relevant physics at work in pulsar magnetospheres and allow us to comment on the implications for future pulsar discoveries

  9. Residual Stress Testing of Outer 3013 Containers

    International Nuclear Information System (INIS)

    Dunn, K.

    2004-01-01

    A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container

  10. Radioiodination of an outer membrane protein in intact Rickettsia prowazekii

    International Nuclear Information System (INIS)

    Smith, D.K.; Winkler, H.H.

    1980-01-01

    Intact Rickettsia prowazekii was radiolabeled with the glucose oxidase-lactoperoxidase method of iodination. Separation of the rickettsial extract into cytoplasmic, outer and inner membrane fractions demonstrated that the outer membrane was preferentially labeled. Analysis of the polypeptides of these fractions on high-resolution slab polyacrylamide gels showed that most of the 125 I was in polypeptide T49, an outer membrane constituent. Additional outer membrane polypeptides were iodinated in broken envelope preparations, demonstrating that T49 is uniquely accessible to the external environment and the asymmetric polypeptide organization of the outer membrane

  11. Granzyme A Cleaves a Mitochondrial Complex I Protein to Initiate Caspase-Independent Cell Death

    Science.gov (United States)

    Martinvalet, Denis; Dykxhoorn, Derek M.; Ferrini, Roger; Lieberman, Judy

    2010-01-01

    SUMMARY The killer lymphocyte protease granzyme A (GzmA) triggers caspase-independent target cell death with morphological features of apoptosis. We previously showed that GzmA acts directly on mitochondria to generate reactive oxygen species (ROS) and disrupt the transmembrane potential (ΔΨm) but does not permeabilize the mitochondrial outer membrane. Mitochondrial damage is critical to GzmA-induced cell death since cells treated with superoxide scavengers are resistant to GzmA. Here we find that GzmA accesses the mitochondrial matrix to cleave the complex I protein NDUFS3, an iron-sulfur subunit of the NADH:ubiquinone oxidoreductase complex I, after Lys56 to interfere with NADH oxidation and generate superoxide anions. Target cells expressing a cleavage site mutant of NDUFS3 are resistant to GzmA-mediated cell death but remain sensitive to GzmB. PMID:18485875

  12. A novel mutation in the mitochondrial DNA cytochrome b gene (MTCYB) in a patient with mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes syndrome.

    Science.gov (United States)

    Emmanuele, Valentina; Sotiriou, Evangelia; Rios, Purificación Gutierrez; Ganesh, Jaya; Ichord, Rebecca; Foley, A Reghan; Akman, H Orhan; Dimauro, Salvatore

    2013-02-01

    Mutations in the mitochondrial DNA cytochrome b gene (MTCYB) have been commonly associated with isolated mitochondrial myopathy and exercise intolerance, rarely with multisystem disorders, and only once with a parkinsonism/mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) overlap syndrome. Here, we describe a novel mutation (m.14864 T>C) in MTCYB in a 15-year-old girl with a clinical history of migraines, epilepsy, sensorimotor neuropathy, and strokelike episodes, a clinical picture reminiscent of MELAS.  The mutation, which changes a highly conserved cysteine to arginine at amino acid position 40 of cytochrome b, was heteroplasmic in muscle, blood, fibroblasts, and urinary sediment from the patient but absent in accessible tissues from her asymptomatic mother. This case demonstrates that MTCYB must be included in the already long list of mitochondrial DNA genes that have been associated with the MELAS phenotype.

  13. Mitochondrial contribution to lipofuscin formation

    Directory of Open Access Journals (Sweden)

    Jeannette König

    2017-04-01

    Moreover, we observed that Lon protease downregulation is linked to a higher lipofuscinogenesis whereas the application of the mitochondrial-targeted antioxidant mitoTEMPO is able to prevent the accumulation of this protein aggregate.

  14. Localization of cytochromes in the outer membrane of Desulfovibrio vulgaris (Hildenborough) and their role in anaerobic biocorrosion.

    Science.gov (United States)

    Van Ommen Kloeke, F; Bryant, R D; Laishley, E J

    1995-12-01

    A protocol was developed whereby the outer and cytoplasmic membranes of the sulfate-reducing bacterium Desulfovibrio vulgaris (Hildenborough) were isolated and partially characterized. The isolated outer membrane fractions from cultures grown under high (100 ppm) and low (5 ppm) Fe2+ conditions were compared by SDS-PAGE electrophoresis, and showed that several protein bands were derepressed under the low iron conditions, most notably at 50 kDa, and 77.5 kDa. Outer membrane isolated from low iron cultured cells was found to contain two proteins, 77.5 kDa and 62.5 kDa in size, that reacted with a heme-specific stain and were referred to as high molecular weight cytochromes. Studies conducted on the low iron isolated outer membrane by a phosphate/mild steel hydrogen evolution system showed that addition of the membrane fraction caused an immediate acceleration in H2 production. A new model for the anaerobic biocorrosion of mild steel is proposed.

  15. Mitochondrial uncouplers with an extraordinary dynamic range.

    Science.gov (United States)

    Lou, Phing-How; Hansen, Birgit S; Olsen, Preben H; Tullin, Søren; Murphy, Michael P; Brand, Martin D

    2007-10-01

    We have discovered that some weak uncouplers (typified by butylated hydroxytoluene) have a dynamic range of more than 10(6) in vitro: the concentration giving measurable uncoupling is less than one millionth of the concentration causing full uncoupling. They achieve this through a high-affinity interaction with the mitochondrial adenine nucleotide translocase that causes significant but limited uncoupling at extremely low uncoupler concentrations, together with more conventional uncoupling at much higher concentrations. Uncoupling at the translocase is not by a conventional weak acid/anion cycling mechanism since it is also caused by substituted triphenylphosphonium molecules, which are not anionic and cannot protonate. Covalent attachment of the uncoupler to a mitochondrially targeted hydrophobic cation sensitizes it to membrane potential, giving a small additional effect. The wide dynamic range of these uncouplers in isolated mitochondria and intact cells reveals a novel allosteric activation of proton transport through the adenine nucleotide translocase and provides a promising starting point for designing safer uncouplers for obesity therapy.

  16. Mitochondrial PKA mediates sperm motility.

    Science.gov (United States)

    Mizrahi, Rashel; Breitbart, Haim

    2014-12-01

    Mitochondria are the major source of ATP to power sperm motility. Phosphorylation of mitochondrial proteins has been proposed as a major regulatory mechanism for mitochondrial bioenergetics. Sperm motility was measured by a computer-assisted analyzer, protein detection by western blotting, membrane potential by tetramethylrhodamine, cellular ATP by luciferase assay and localization of PKA by immuno-electron microscopy. Bicarbonate is essential for the creation of mitochondrial electro-chemical gradient, ATP synthesis and sperm motility. Bicarbonate stimulates PKA-dependent phosphorylation of two 60kDa proteins identified as Tektin and glucose-6-phosphate isomerase. This phosphorylation was inhibited by respiration inhibition and phosphorylation could be restored by glucose in the presence of bicarbonate. However, this effect of glucose cannot be seen when the mitochondrial ATP/ADP exchanger was inhibited indicating that glycolytic-produced ATP is transported into the mitochondria and allows PKA-dependent protein phosphorylation inside the mitochondria. Bicarbonate activates mitochondrial soluble adenylyl cyclase (sAC) which catalyzes cAMP production leading to the activation of mitochondrial PKA. Glucose can overcome the lack of ATP in the absence of bicarbonate but it cannot affect the mitochondrial sAC/PKA system, therefore the PKA-dependent phosphorylation of the 60kDa proteins does not occur in the absence of bicarbonate. Production of CO2 in Krebs cycle, which is converted to bicarbonate is essential for sAC/PKA activation leading to mitochondrial membrane potential creation and ATP synthesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Mitochondrial dysfunction and organophosphorus compounds

    Energy Technology Data Exchange (ETDEWEB)

    Karami-Mohajeri, Somayyeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: Mohammad.Abdollahi@UToronto.Ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2013-07-01

    Organophosphorous (OPs) pesticides are the most widely used pesticides in the agriculture and home. However, many acute or chronic poisoning reports about OPs have been published in the recent years. Mitochondria as a site of cellular oxygen consumption and energy production can be a target for OPs poisoning as a non-cholinergic mechanism of toxicity of OPs. In the present review, we have reviewed and criticized all the evidences about the mitochondrial dysfunctions as a mechanism of toxicity of OPs. For this purpose, all biochemical, molecular, and morphological data were retrieved from various studies. Some toxicities of OPs are arisen from dysfunction of mitochondrial oxidative phosphorylation through alteration of complexes I, II, III, IV and V activities and disruption of mitochondrial membrane. Reductions of adenosine triphosphate (ATP) synthesis or induction of its hydrolysis can impair the cellular energy. The OPs disrupt cellular and mitochondrial antioxidant defense, reactive oxygen species generation, and calcium uptake and promote oxidative and genotoxic damage triggering cell death via cytochrome C released from mitochondria and consequent activation of caspases. The mitochondrial dysfunction induced by OPs can be restored by use of antioxidants such as vitamin E and C, alpha-tocopherol, electron donors, and through increasing the cytosolic ATP level. However, to elucidate many aspect of mitochondrial toxicity of Ops, further studies should be performed. - Highlights: • As a non-cholinergic mechanism of toxicity, mitochondria is a target for OPs. • OPs affect action of complexes I, II, III, IV and V in the mitochondria. • OPs reduce mitochondrial ATP. • OPs promote oxidative and genotoxic damage via release of cytochrome C from mitochondria. • OP-induced mitochondrial dysfunction can be restored by increasing the cytosolic ATP.

  18. Mitochondrial dysfunction and organophosphorus compounds

    International Nuclear Information System (INIS)

    Karami-Mohajeri, Somayyeh; Abdollahi, Mohammad

    2013-01-01

    Organophosphorous (OPs) pesticides are the most widely used pesticides in the agriculture and home. However, many acute or chronic poisoning reports about OPs have been published in the recent years. Mitochondria as a site of cellular oxygen consumption and energy production can be a target for OPs poisoning as a non-cholinergic mechanism of toxicity of OPs. In the present review, we have reviewed and criticized all the evidences about the mitochondrial dysfunctions as a mechanism of toxicity of OPs. For this purpose, all biochemical, molecular, and morphological data were retrieved from various studies. Some toxicities of OPs are arisen from dysfunction of mitochondrial oxidative phosphorylation through alteration of complexes I, II, III, IV and V activities and disruption of mitochondrial membrane. Reductions of adenosine triphosphate (ATP) synthesis or induction of its hydrolysis can impair the cellular energy. The OPs disrupt cellular and mitochondrial antioxidant defense, reactive oxygen species generation, and calcium uptake and promote oxidative and genotoxic damage triggering cell death via cytochrome C released from mitochondria and consequent activation of caspases. The mitochondrial dysfunction induced by OPs can be restored by use of antioxidants such as vitamin E and C, alpha-tocopherol, electron donors, and through increasing the cytosolic ATP level. However, to elucidate many aspect of mitochondrial toxicity of Ops, further studies should be performed. - Highlights: • As a non-cholinergic mechanism of toxicity, mitochondria is a target for OPs. • OPs affect action of complexes I, II, III, IV and V in the mitochondria. • OPs reduce mitochondrial ATP. • OPs promote oxidative and genotoxic damage via release of cytochrome C from mitochondria. • OP-induced mitochondrial dysfunction can be restored by increasing the cytosolic ATP

  19. A mitochondrially targeted compound delays aging in yeast through a mechanism linking mitochondrial membrane lipid metabolism to mitochondrial redox biology

    Directory of Open Access Journals (Sweden)

    Michelle T. Burstein

    2014-01-01

    Full Text Available A recent study revealed a mechanism of delaying aging in yeast by a natural compound which specifically impacts mitochondrial redox processes. In this mechanism, exogenously added lithocholic bile acid enters yeast cells, accumulates mainly in the inner mitochondrial membrane, and elicits an age-related remodeling of phospholipid synthesis and movement within both mitochondrial membranes. Such remodeling of mitochondrial phospholipid dynamics progresses with the chronological age of a yeast cell and ultimately causes significant changes in mitochondrial membrane lipidome. These changes in the composition of membrane phospholipids alter mitochondrial abundance and morphology, thereby triggering changes in the age-related chronology of such longevity-defining redox processes as mitochondrial respiration, the maintenance of mitochondrial membrane potential, the preservation of cellular homeostasis of mitochondrially produced reactive oxygen species, and the coupling of electron transport to ATP synthesis.

  20. Melatonin and human mitochondrial diseases

    Directory of Open Access Journals (Sweden)

    Reza Sharafati-Chaleshtori

    2017-01-01

    Full Text Available Mitochondrial dysfunction is one of the main causative factors in a wide variety of complications such as neurodegenerative disorders, ischemia/reperfusion, aging process, and septic shock. Decrease in respiratory complex activity, increase in free radical production, increase in mitochondrial synthase activity, increase in nitric oxide production, and impair in electron transport system and/or mitochondrial permeability are considered as the main factors responsible for mitochondrial dysfunction. Melatonin, the pineal gland hormone, is selectively taken up by mitochondria and acts as a powerful antioxidant, regulating the mitochondrial bioenergetic function. Melatonin increases the permeability of membranes and is the stimulator of antioxidant enzymes including superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase. It also acts as an inhibitor of lipoxygenase. Melatonin can cause resistance to oxidation damage by fixing the microsomal membranes. Melatonin has been shown to retard aging and inhibit neurodegenerative disorders, ischemia/reperfusion, septic shock, diabetes, cancer, and other complications related to oxidative stress. The purpose of the current study, other than introducing melatonin, was to present the recent findings on clinical effects in diseases related to mitochondrial dysfunction including diabetes, cancer, gastrointestinal diseases, and diseases related to brain function.

  1. Mitochondrial Metabolism in Aging Heart

    Science.gov (United States)

    Lesnefsky, Edward J.; Chen, Qun; Hoppel, Charles L.

    2016-01-01

    Altered mitochondrial metabolism is the underlying basis for the increased sensitivity in the aged heart to stress. The aged heart exhibits impaired metabolic flexibility, with a decreased capacity to oxidize fatty acids and enhanced dependence on glucose metabolism. Aging impairs mitochondrial oxidative phosphorylation, with a greater role played by the mitochondria located between the myofibrils, the interfibrillar mitochondria. With aging, there is a decrease in activity of complexes III and IV, which account for the decrease in respiration. Furthermore, aging decreases mitochondrial content among the myofibrils. The end result is that in the interfibrillar area there is an approximate 50% decrease in mitochondrial function, affecting all substrates. The defective mitochondria persist in the aged heart, leading to enhanced oxidant production and oxidative injury and the activation of oxidant signaling for cell death. Aging defects in mitochondria represent new therapeutic targets, whether by manipulation of the mitochondrial proteome, modulation of electron transport, activation of biogenesis or mitophagy, or the regulation of mitochondrial fission and fusion. These mechanisms provide new ways to attenuate cardiac disease in elders by preemptive treatment of age-related defects, in contrast to the treatment of disease-induced dysfunction. PMID:27174952

  2. ROS-mediated PARP activity undermines mitochondrial function after permeability transition pore opening during myocardial ischemia-reperfusion.

    Science.gov (United States)

    Schriewer, Jacqueline M; Peek, Clara Bien; Bass, Joseph; Schumacker, Paul T

    2013-04-18

    Ischemia-reperfusion (I/R) studies have implicated oxidant stress, the mitochondrial permeability transition pore (mPTP), and poly(ADP-ribose) polymerase (PARP) as contributing factors in myocardial cell death. However, the interdependence of these factors in the intact, blood-perfused heart is not known. We therefore wanted to determine whether oxidant stress, mPTP opening, and PARP activity contribute to the same death pathway after myocardial I/R. A murine left anterior descending coronary artery (LAD) occlusion (30 minutes) and release (1 to 4 hours) model was employed. Experimental groups included controls and antioxidant-treated, mPTP-inhibited, or PARP-inhibited hearts. Antioxidant treatment prevented oxidative damage, mPTP opening, ATP depletion, and PARP activity, placing oxidant stress as the proximal death trigger. Genetic deletion of cyclophilin D (CypD(-/-)) prevented loss of total NAD(+) and PARP activity, and mPTP-mediated loss of mitochondrial function. Control hearts showed progressive mitochondrial depolarization and loss of ATP from 1.5 to 4 hours of reperfusion, but not outer mitochondrial membrane rupture. Neither genetic deletion of PARP-1 nor its pharmacological inhibition prevented the initial mPTP-mediated depolarization or loss of ATP, but PARP ablation did allow mitochondrial recovery by 4 hours of reperfusion. These results indicate that oxidant stress, the mPTP, and PARP activity contribute to a single death pathway after I/R in the heart. PARP activation undermines cell survival by preventing mitochondrial recovery after mPTP opening early in reperfusion. This suggests that PARP-mediated prolongation of mitochondrial depolarization contributes significantly to cell death via an energetic crisis rather than by mitochondrial outer membrane rupture.

  3. Sequencing and comparing whole mitochondrial genomes ofanimals

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.; Macey, J. Robert; Medina, Monica

    2005-04-22

    Comparing complete animal mitochondrial genome sequences is becoming increasingly common for phylogenetic reconstruction and as a model for genome evolution. Not only are they much more informative than shorter sequences of individual genes for inferring evolutionary relatedness, but these data also provide sets of genome-level characters, such as the relative arrangements of genes, that can be especially powerful. We describe here the protocols commonly used for physically isolating mtDNA, for amplifying these by PCR or RCA, for cloning,sequencing, assembly, validation, and gene annotation, and for comparing both sequences and gene arrangements. On several topics, we offer general observations based on our experiences to date with determining and comparing complete mtDNA sequences.

  4. Mitochondrial bioenergetics during the initiation of mercuric chloride-induced renal injury. I. Direct effects of in vitro mercuric chloride on renal cortical mitochondrial function

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg, J.M. (Veterans Administration Medical Center, Ann Arbor, MI); Harding, P.G.; Humes, H.D.

    1982-01-01

    Increasing data suggest that mitochondrial dysfunction may be an important early component of nephrotoxin-induced changes in renal cell function and viability. This study was designed to obtain more detailed information about the effects on several basic bioenergetic parameters of the direct interaction of Hg/sup 2 +/ with renal cortical mitochondria in vitro as a necessary prelude to studies of mitochondrial functional changes after treatment with mercuric chloride in vivo. Beginning at a threshhold level of 2 nmol of Hg/sup 2 +//mg of mitochondrial protein Hg/sup 2 +/ induced marked stimulation of State 4 respiration, mild inhibition of State 3 respiration, and 2,4-dinitrophenol uncoupled respiration, a striking increase in atractyloside-insensitive ADP uptake and stimulation of both basal- and Mg/sup 2 +/-activated oligomycin-sensitive mitochondrial ATPase activity. These effects of Hg/sup 2 +/ could be prevented and reversed by the sulfhydryl reagent dithioerythritol and by albumin but were not affected by Mg/sup 2 +/. Detailed studies on the addition of HgCl/sub 2/ to the preparation at different stages of the mitochondrial isolation procedure demonstrated that the presence of other proteins decreased mitochondrial Hg/sup 2 +/ binding, that the Hg/sup 2 +/ was not readily washed off the mitochondria by nonprotein-containing solutions, and that prolonged exposure of mitochondria to Hg/sup 2 +/ during the isolation procedure did not markedly alter its functional effects on their reversibility as assessed on the final mitochondrial preparation. These data provide an important basis for critically assessing the changes in function of mitochondria isolated after in vivo treatment with mercuric chloride.

  5. Recurrent Neural Network for Computing Outer Inverse.

    Science.gov (United States)

    Živković, Ivan S; Stanimirović, Predrag S; Wei, Yimin

    2016-05-01

    Two linear recurrent neural networks for generating outer inverses with prescribed range and null space are defined. Each of the proposed recurrent neural networks is based on the matrix-valued differential equation, a generalization of dynamic equations proposed earlier for the nonsingular matrix inversion, the Moore-Penrose inversion, as well as the Drazin inversion, under the condition of zero initial state. The application of the first approach is conditioned by the properties of the spectrum of a certain matrix; the second approach eliminates this drawback, though at the cost of increasing the number of matrix operations. The cases corresponding to the most common generalized inverses are defined. The conditions that ensure stability of the proposed neural network are presented. Illustrative examples present the results of numerical simulations.

  6. Ageing of the LHCb outer tracker

    CERN Document Server

    Blom, M R; Tuning, N

    2009-01-01

    The modules of the LHCb outer tracker have shown to suffer severe gain loss under moderate irradiation. This process is called ageing. Ageing of the modules results from contamination of the gas system by glue, araldite AY 103-1, used in their construction. In this thesis the ageing process will be shown. The schemes known to reduce, reverse, or prevent ageing have been investigated to determine their effect on the detector performance. The addition of O2 to the gas mixture lowers the detector response by an acceptable amount and does not affect the gas transport properties significantly. The ageing rate is decreased after extensive flushing and HV training could eventually repair the irradiation damage. The risks of HV training have been assessed. Furthermore, several gaseous and aquatic additions have been tested for their capability to prevent, or moderate ageing, but none showed significant improvement.

  7. The fate of the outer plasmasphere

    International Nuclear Information System (INIS)

    Elphic, R.C.; Thomsen, M.F.; Borovsky, J.E.

    1997-01-01

    Both the solar wind and the ionosphere contribute to Earth close-quote s magnetospheric plasma environment. However, it is not widely appreciated that the plasmasphere is a large reservoir of ionospheric ions that can be tapped to populate the plasma sheet. We employ empirical models of high-latitude ionospheric convection and the geomagnetic field to describe the transport of outer plasmasphere flux tubes from the dayside, over the polar cap and into the magnetotail during the early phases of a geomagnetic storm. We calculate that this process can give rise to high densities of cold plasma in the magnetotail lobes and in the near-Earth plasma sheet during times of enhanced geomagnetic activity, and especially during storms. This model can help explain both polar cap ionization patches and the presence of cold flowing ions downtail.copyright 1997 American Geophysical Union

  8. Impulsive ion acceleration in earth's outer magnetosphere

    International Nuclear Information System (INIS)

    Baker, D.N.; Belian, R.D.

    1985-01-01

    Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions are not of dominant importance for magnetotail plasma dynamics, they serve as an important tracer population. Their absolute intensity and brief temporal appearance bespeaks a strong and rapid acceleration process in the near-tail, very probably involving large induced electric fields substantially greater than those associated with cross-tail potential drops. Subsequent to their impulsive acceleration, these ions are injected into the outer trapping regions forming ion ''drift echo'' events, as well as streaming tailward away from their acceleration site in the near-earth plasma sheet. Most auroral ion acceleration processes occur (or are greatly enhanced) during the time that these global magnetospheric events are occurring in the magnetotail. A qualitative model relating energetic ion populations to near-tail magnetic reconnection at substorm onset followed by global redistribution is quite successful in explaining the primary observational features. Recent measurements of the elemental composition and charge-states have proven valuable for showing the source (solar wind or ionosphere) of the original plasma population from which the ions were accelerated

  9. Antigen sequence typing of outer membrane protein (fetA gene of Neisseria meningitidis serogroup A from Delhi & adjoining areas

    Directory of Open Access Journals (Sweden)

    S Dwivedi

    2014-01-01

    Full Text Available Background & objectives: Meningitis caused by Neisseria meningitidis is a fatal disease. Meningococcal meningitis is an endemic disease in Delhi and irregular pattern of outbreaks has been reported in India. All these outbreaks were associated with serogroup A. Detailed molecular characterization of N. meningitidis is required for the management of this fatal disease. In this study, we characterized antigenic diversity of surface exposed outer membrane protein (OMP FetA antigen of N. meningitidis serogroup A isolates obtained from cases of invasive meningococcal meningitis in Delhi, India. Methods: Eight isolates of N. meningitidis were collected from cerebrospinal fluid during October 2008 to May 2011 from occasional cases of meningococcal meningitis. Seven isolates were from outbreaks of meningococcal meningitis in 2005-2006 in Delhi and its adjoining areas. These were subjected to molecular typing of fetA gene, an outer membrane protein gene. Results: All 15 N. meningitides isolates studied were serogroup A. This surface exposed porin is putatively under immune pressure. Hence as a part of molecular characterization, genotyping was carried out to find out the diversity in outer membrane protein (FetA gene among the circulating isolates of N. meningitidis. All 15 isolates proved to be of the same existing allele type of FetA variable region (VR when matched with global database. The allele found was F3-1 for all the isolates. Interpretation & conclusions: There was no diversity reported in the outer membrane protein FetA in the present study and hence this protein appeared to be a stable molecule. More studies on molecular characterization of FetA antigen are required from different serogroups circulating in different parts of the world.

  10. Mitochondrial Nucleoid: Shield and Switch of the Mitochondrial Genome

    Science.gov (United States)

    2017-01-01

    Mitochondria preserve very complex and distinctively unique machinery to maintain and express the content of mitochondrial DNA (mtDNA). Similar to chromosomes, mtDNA is packaged into discrete mtDNA-protein complexes referred to as a nucleoid. In addition to its role as a mtDNA shield, over 50 nucleoid-associated proteins play roles in mtDNA maintenance and gene expression through either temporary or permanent association with mtDNA or other nucleoid-associated proteins. The number of mtDNA(s) contained within a single nucleoid is a fundamental question but remains a somewhat controversial issue. Disturbance in nucleoid components and mutations in mtDNA were identified as significant in various diseases, including carcinogenesis. Significant interest in the nucleoid structure and its regulation has been stimulated in relation to mitochondrial diseases, which encompass diseases in multicellular organisms and are associated with accumulation of numerous mutations in mtDNA. In this review, mitochondrial nucleoid structure, nucleoid-associated proteins, and their regulatory roles in mitochondrial metabolism are briefly addressed to provide an overview of the emerging research field involving mitochondrial biology. PMID:28680532

  11. Subdominant Outer Membrane Antigens in Anaplasma marginale: Conservation, Antigenicity, and Protective Capacity Using Recombinant Protein.

    Directory of Open Access Journals (Sweden)

    Deirdre R Ducken

    Full Text Available Anaplasma marginale is a tick-borne rickettsial pathogen of cattle with a worldwide distribution. Currently a safe and efficacious vaccine is unavailable. Outer membrane protein (OMP extracts or a defined surface protein complex reproducibly induce protective immunity. However, there are several knowledge gaps limiting progress in vaccine development. First, are these OMPs conserved among the diversity of A. marginale strains circulating in endemic regions? Second, are the most highly conserved outer membrane proteins in the immunogens recognized by immunized and protected animals? Lastly, can this subset of OMPs recognized by antibody from protected vaccinates and conserved among strains recapitulate the protection of outer membrane vaccines? To address the first goal, genes encoding OMPs AM202, AM368, AM854, AM936, AM1041, and AM1096, major subdominant components of the outer membrane, were cloned and sequenced from geographically diverse strains and isolates. AM202, AM936, AM854, and AM1096 share 99.9 to 100% amino acid identity. AM1041 has 97.1 to 100% and AM368 has 98.3 to 99.9% amino acid identity. While all four of the most highly conserved OMPs were recognized by IgG from animals immunized with outer membranes, linked surface protein complexes, or unlinked surface protein complexes and shown to be protected from challenge, the highest titers and consistent recognition among vaccinates were to AM854 and AM936. Consequently, animals were immunized with recombinant AM854 and AM936 and challenged. Recombinant vaccinates and purified outer membrane vaccinates had similar IgG and IgG2 responses to both proteins. However, the recombinant vaccinates developed higher bacteremia after challenge as compared to adjuvant-only controls and outer membrane vaccinates. These results provide the first evidence that vaccination with specific antigens may exacerbate disease. Progressing from the protective capacity of outer membrane formulations to

  12. Storm/substorm signatures in the outer belt

    International Nuclear Information System (INIS)

    Korth, A.; Friedel, R.H.W.; Mouikis, C.; Fennell, J.F.

    1998-01-01

    The response of the ring current region is compared for periods of storm and substorm activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and substorm (AE) activity and examine compositional changes. Substorm activity leads to the intensification of the ring current at higher L (L ∼ 6) and lower ring current energies compared to storms (L ∼ 4). The O + /H + ratio during substorms remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated substorms with an AE ∼ 900 nT lead to a ΔDst of ∼ 30 nT, but do not contribute to Dst during storm main phase as substorm injections do not form a symmetric ring current during such disturbed times

  13. Outer membrane vesicles enhance the carcinogenic potential of Helicobacter pylori.

    Science.gov (United States)

    Chitcholtan, Kenny; Hampton, Mark B; Keenan, Jacqueline I

    2008-12-01

    Chronic Helicobacter pylori infection is associated with an increased risk of gastric carcinogenesis. These non-invasive bacteria colonize the gastric mucosa and constitutively shed small outer membrane vesicles (OMV). In this study, we investigated the direct effect of H.pylori OMV on cellular events associated with carcinogenesis. We observed increased micronuclei formation in AGS human gastric epithelial cells treated with OMV isolated from a toxigenic H.pylori strain (60190). This effect was absent in OMV from strain 60190v:1 that has a mutant vacA, indicating VacA-dependent micronuclei formation. VacA induces intracellular vacuolation, and reduced acridine orange staining indicated disruption in the integrity of these vacuoles. This was accompanied by an alteration in iron metabolism and glutathione (GSH) loss, suggesting a role for oxidative stress in genomic damage. Increasing intracellular GSH levels with a GSH ester abrogated the VacA-mediated increase in micronuclei formation. In conclusion, OMV-mediated delivery of VacA to the gastric epithelium may constitute a new mechanism for H.pylori-induced gastric carcinogenesis.

  14. Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival of Vibrio cholerae and Suppresses Viability of Acanthamoeba castellanii

    Directory of Open Access Journals (Sweden)

    Soni Priya Valeru

    2014-01-01

    Full Text Available Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive inside Acanthamoeba castellanii. It has been shown that V. cholerae expresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA and outer membrane vesicles (OMVs in survival of V. cholerae alone and during its interaction with A. castellanii. The results showed that an OmpA mutant of V. cholerae survived longer than wild-type V. cholerae when cultivated alone. Cocultivation with A. castellanii enhanced the survival of both bacterial strains and OmpA protein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of the OmpA mutant of V. cholerae decreased the viability of A. castellanii and this bacterial strain released more OMVs than wild-type V. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from the OmpA mutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule for OmpA in survival of V. cholerae and OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment.

  15. Formation and Regulation of Mitochondrial Membranes

    Directory of Open Access Journals (Sweden)

    Laila Cigana Schenkel

    2014-01-01

    Full Text Available Mitochondrial membrane phospholipids are essential for the mitochondrial architecture, the activity of respiratory proteins, and the transport of proteins into the mitochondria. The accumulation of phospholipids within mitochondria depends on a coordinate synthesis, degradation, and trafficking of phospholipids between the endoplasmic reticulum (ER and mitochondria as well as intramitochondrial lipid trafficking. Several studies highlight the contribution of dietary fatty acids to the remodeling of phospholipids and mitochondrial membrane homeostasis. Understanding the role of phospholipids in the mitochondrial membrane and their metabolism will shed light on the molecular mechanisms involved in the regulation of mitochondrial function and in the mitochondrial-related diseases.

  16. Identification of immunogenic outer membrane proteins of Haemophilus influenzae type b in the infant rat model system

    International Nuclear Information System (INIS)

    Hansen, E.J.; Frisch, C.F.; McDade, R.L. Jr.; Johnston, K.H.

    1981-01-01

    Outer membrane proteins of Haemophilus influenzae type b which are immunogenic in infant rats were identified by a radioimmunoprecipitation method. Intact cells of H. influenzae type b were radioiodinated by a lactoperoxidase-catalyzed procedure, and an outer membrane-containing fraction was prepared from these cells. These radioiodinated outer membranes were mixed with sera obtained from rats convalescing from systemic H. influenzae type b disease induced at 6 days of age, and the resultant (antibody-outer membrane protein antigen) complexes were extracted from these membranes by treatment with nonionic detergent and ethylenediaminetetraacetic acid. These soluble antibody-antigen complexes were isolated by means of adsorption to protein A-bearing staphylococci, and the radioiodinated protein antigens were identified by gel electrophoresis followed by autoradiography. Infant rats were shown to mount a readily detectable antibody response to several different proteins present in the outer membrane of H. influenzae type b. Individual infant rats were found to vary both qualitatively and quantitatively in their immune response to these immunogenic outer membrane proteins

  17. Mitochondrial DNA levels in Huntington disease leukocytes and dermal fibroblasts.

    Science.gov (United States)

    Jędrak, Paulina; Krygier, Magdalena; Tońska, Katarzyna; Drozd, Małgorzata; Kaliszewska, Magdalena; Bartnik, Ewa; Sołtan, Witold; Sitek, Emilia J; Stanisławska-Sachadyn, Anna; Limon, Janusz; Sławek, Jarosław; Węgrzyn, Grzegorz; Barańska, Sylwia

    2017-08-01

    Huntington disease (HD) is an inherited neurodegenerative disorder caused by mutations in the huntingtin gene. Involvement of mitochondrial dysfunctions in, and especially influence of the level of mitochondrial DNA (mtDNA) on, development of this disease is unclear. Here, samples of blood from 84 HD patients and 79 controls, and dermal fibroblasts from 10 HD patients and 9 controls were analysed for mtDNA levels. Although the type of mitochondrial haplogroup had no influence on the mtDNA level, and there was no correlation between mtDNA level in leukocytes in HD patients and various parameters of HD severity, some considerable differences between HD patients and controls were identified. The average mtDNA/nDNA relative copy number was significantly higher in leukocytes, but lower in fibroblasts, of symptomatic HD patients relative to the control group. Moreover, HD women displayed higher mtDNA levels in leukocytes than HD men. Because this is the largest population analysed to date, these results might contribute to explanation of discrepancies between previously published studies concerning levels of mtDNA in cells of HD patients. We suggest that the size of the investigated population and type of cells from which DNA is isolated could significantly affect results of mtDNA copy number estimation in HD. Hence, these parameters should be taken into consideration in studies on mtDNA in HD, and perhaps also in other diseases where mitochondrial dysfunction occurs.

  18. Two potential Petunia hybrida mitochondrial DNA replication origins show structural and in vitro functional homology with the animal mitochondrial DNA heavy and light strand replication origins

    NARCIS (Netherlands)

    Haas, Jan M. de; Hille, Jacques; Kors, Frank; Meer, Bert van der; Kool, Ad J.; Folkerts, Otto; Nijkamp, H. John J.

    1991-01-01

    Four Petunia hybrida mitochondrial (mt) DNA fragments have been isolated, sequenced, localized on the physical map and analyzed for their ability to initiate specific DNA synthesis. When all four mtDNA fragments were tested as templates in an in vitro DNA synthesizing lysate system, developed from

  19. Antibodies against Shigella flexneri adhesion molecule outer ...

    African Journals Online (AJOL)

    OMP) as an adhesion factor and examine its ability to cross-react with the OMPs of other Shigella species. Methods: OMP was isolated from the bacterium S. flexneri after shaving the pili using a pili bacterial cutter in a solution of 0.5 ...

  20. Mitochondrial quality control pathways as determinants of metabolic health

    NARCIS (Netherlands)

    Held, Ntsiki M.; Houtkooper, Riekelt H.

    2015-01-01

    Mitochondrial function is key for maintaining cellular health, while mitochondrial failure is associated with various pathologies, including inherited metabolic disorders and age-related diseases. In order to maintain mitochondrial quality, several pathways of mitochondrial quality control have

  1. Hyperglycemia decreases mitochondrial function: The regulatory role of mitochondrial biogenesis

    International Nuclear Information System (INIS)

    Palmeira, Carlos M.; Rolo, Anabela P.; Berthiaume, Jessica; Bjork, James A.; Wallace, Kendall B.

    2007-01-01

    Increased generation of reactive oxygen species (ROS) is implicated in 'glucose toxicity' in diabetes. However, little is known about the action of glucose on the expression of transcription factors in hepatocytes, especially those involved in mitochondrial DNA (mtDNA) replication and transcription. Since mitochondrial functional capacity is dynamically regulated, we hypothesized that stressful conditions of hyperglycemia induce adaptations in the transcriptional control of cellular energy metabolism, including inhibition of mitochondrial biogenesis and oxidative metabolism. Cell viability, mitochondrial respiration, ROS generation and oxidized proteins were determined in HepG2 cells cultured in the presence of either 5.5 mM (control) or 30 mM glucose (high glucose) for 48 h, 96 h and 7 days. Additionally, mtDNA abundance, plasminogen activator inhibitor-1 (PAI-1), mitochondrial transcription factor A (TFAM) and nuclear respiratory factor-1 (NRF-1) transcripts were evaluated by real time PCR. High glucose induced a progressive increase in ROS generation and accumulation of oxidized proteins, with no changes in cell viability. Increased expression of PAI-1 was observed as early as 96 h of exposure to high glucose. After 7 days in hyperglycemia, HepG2 cells exhibited inhibited uncoupled respiration and decreased MitoTracker Red fluorescence associated with a 25% decrease in mtDNA and 16% decrease in TFAM transcripts. These results indicate that glucose may regulate mtDNA copy number by modulating the transcriptional activity of TFAM in response to hyperglycemia-induced ROS production. The decrease of mtDNA content and inhibition of mitochondrial function may be pathogenic hallmarks in the altered metabolic status associated with diabetes

  2. Prospects for therapeutic mitochondrial transplantation.

    Science.gov (United States)

    Gollihue, Jenna L; Rabchevsky, Alexander G

    2017-07-01

    Mitochondrial dysfunction has been implicated in a multitude of diseases and pathological conditions- the organelles that are essential for life can also be major players in contributing to cell death and disease. Because mitochondria are so well established in our existence, being present in all cell types except for red blood cells and having the responsibility of providing most of our energy needs for survival, then dysfunctional mitochondria can elicit devastating cellular pathologies that can be widespread across the entire organism. As such, the field of "mitochondrial medicine" is emerging in which disease states are being targeted therapeutically at the level of the mitochondrion, including specific antioxidants, bioenergetic substrate additions, and membrane uncoupling agents. New and compelling research investigating novel techniques for mitochondrial transplantation to replace damaged or dysfunctional mitochondria with exogenous healthy mitochondria has shown promising results, including tissue sparing accompanied by increased energy production and decreased oxidative damage. Various experimental techniques have been attempted and each has been challenged to accomplish successful transplantation. The purpose of this review is to present the history of mitochondrial transplantation, the different techniques used for both in vitro and in vivo delivery, along with caveats and pitfalls that have been discovered along the way. Results from such pioneering studies are promising and could be the next big wave of "mitochondrial medicine" once technical hurdles are overcome. Copyright © 2017 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  3. Will Outer Tropical Cyclone Size Change due to Anthropogenic Warming?

    Science.gov (United States)

    Schenkel, B. A.; Lin, N.; Chavas, D. R.; Vecchi, G. A.; Knutson, T. R.; Oppenheimer, M.

    2017-12-01

    Prior research has shown significant interbasin and intrabasin variability in outer tropical cyclone (TC) size. Moreover, outer TC size has even been shown to vary substantially over the lifetime of the majority of TCs. However, the factors responsible for both setting initial outer TC size and determining its evolution throughout the TC lifetime remain uncertain. Given these gaps in our physical understanding, there remains uncertainty in how outer TC size will change, if at all, due to anthropogenic warming. The present study seeks to quantify whether outer TC size will change significantly in response to anthropogenic warming using data from a high-resolution global climate model and a regional hurricane model. Similar to prior work, the outer TC size metric used in this study is the radius in which the azimuthal-mean surface azimuthal wind equals 8 m/s. The initial results from the high-resolution global climate model data suggest that the distribution of outer TC size shifts significantly towards larger values in each global TC basin during future climates, as revealed by 1) statistically significant increase of the median outer TC size by 5-10% (p<0.05) according to a 1,000-sample bootstrap resampling approach with replacement and 2) statistically significant differences between distributions of outer TC size from current and future climate simulations as shown using two-sample Kolmogorov Smirnov testing (p<<0.01). Additional analysis of the high-resolution global climate model data reveals that outer TC size does not uniformly increase within each basin in future climates, but rather shows substantial locational dependence. Future work will incorporate the regional mesoscale hurricane model data to help focus on identifying the source of the spatial variability in outer TC size increases within each basin during future climates and, more importantly, why outer TC size changes in response to anthropogenic warming.

  4. Resveratrol induces mitochondrial biogenesis in endothelial cells.

    Science.gov (United States)

    Csiszar, Anna; Labinskyy, Nazar; Pinto, John T; Ballabh, Praveen; Zhang, Hanrui; Losonczy, Gyorgy; Pearson, Kevin; de Cabo, Rafael; Pacher, Pal; Zhang, Cuihua; Ungvari, Zoltan

    2009-07-01

    Pathways that regulate mitochondrial biogenesis are potential therapeutic targets for the amelioration of endothelial dysfunction and vascular disease. Resveratrol was shown to impact mitochondrial function in skeletal muscle and the liver, but its role in mitochondrial biogenesis in endothelial cells remains poorly defined. The present study determined whether resveratrol induces mitochondrial biogenesis in cultured human coronary arterial endothelial cells (CAECs). In CAECs resveratrol increased mitochondrial mass and mitochondrial DNA content, upregulated protein expression of electron transport chain constituents, and induced mitochondrial biogenesis factors (proliferator-activated receptor-coactivator-1alpha, nuclear respiratory factor-1, mitochondrial transcription factor A). Sirtuin 1 (SIRT1) was induced, and endothelial nitric oxide (NO) synthase (eNOS) was upregulated in a SIRT1-dependent manner. Knockdown of SIRT1 (small interfering RNA) or inhibition of NO synthesis prevented resveratrol-induced mitochondrial biogenesis. In aortas of type 2 diabetic (db/db) mice impaired mitochondrial biogenesis was normalized by chronic resveratrol treatment, showing the in vivo relevance of our findings. Resveratrol increases mitochondrial content in endothelial cells via activating SIRT1. We propose that SIRT1, via a pathway that involves the upregulation of eNOS, induces mitochondrial biogenesis. Resveratrol induced mitochondrial biogenesis in the aortas of type 2 diabetic mice, suggesting the potential for new treatment approaches targeting endothelial mitochondria in metabolic diseases.

  5. Isolation of rat adrenocortical mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Solinas, Paola [Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Department of Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Fujioka, Hisashi [Electron Microscopy Facility, Department of Pharmacology, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Tandler, Bernard [Department of Biological Sciences, School of Dental Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Hoppel, Charles L., E-mail: charles.hoppel@case.edu [Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Department of Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States)

    2012-10-12

    Highlights: Black-Right-Pointing-Pointer A method for isolation of adrenocortical mitochondria from the adrenal gland of rats is described. Black-Right-Pointing-Pointer The purified isolated mitochondria show excellent morphological integrity. Black-Right-Pointing-Pointer The properties of oxidative phosphorylation are excellent. Black-Right-Pointing-Pointer The method increases the opportunity of direct analysis of adrenal mitochondria from small animals. -- Abstract: This report describes a relatively simple and reliable method for isolating adrenocortical mitochondria from rats in good, reasonably pure yield. These organelles, which heretofore have been unobtainable in isolated form from small laboratory animals, are now readily accessible. A high degree of mitochondrial purity is shown by the electron micrographs, as well as the structural integrity of each mitochondrion. That these organelles have retained their functional integrity is shown by their high respiratory control ratios. In general, the biochemical performance of these adrenal cortical mitochondria closely mirrors that of typical hepatic or cardiac mitochondria.

  6. Using Yeast to Easily Determine Mitochondrial Functionality with 1-(4,5-Dimethylthiazol-2-yl)-3,5-Diphenyltetrazolium Bromide (MTT) Assay

    Science.gov (United States)

    Sanchez, Norma Silvia; Konigsberg, Mina

    2006-01-01

    Mitochondrial respiration is an important topic in biochemical courses, but at the same time it is a very arduous and challenging subject for the students to comprehend. In teaching laboratories, experiments are also difficult to perform because mitochondrial isolation as well as oxygen consumption determinations require expensive equipment,…

  7. Metabolic Characterization of Intact Cells Reveals Intracellular Amyloid Beta but Not Its Precursor Protein to Reduce Mitochondrial Respiration

    Science.gov (United States)

    Schaefer, Patrick M.; von Einem, Bjoern; Walther, Paul; Calzia, Enrico; von Arnim, Christine A. F.

    2016-01-01

    One hallmark of Alzheimer´s disease are senile plaques consisting of amyloid beta (Aβ), which derives from the processing of the amyloid precursor protein (APP). Mitochondrial dysfunction has been linked to the pathogenesis of Alzheimer´s disease and both Aβ and APP have been reported to affect mitochondrial function in isolated systems. However, in intact cells, considering a physiological localization of APP and Aβ, it is pending what triggers the mitochondrial defect. Thus, the aim of this study was to dissect the impact of APP versus Aβ in inducing mitochondrial alterations with respect to their subcellular localization. We performed an overexpression of APP or beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), increasing APP and Aβ levels or Aβ alone, respectively. Conducting a comprehensive metabolic characterization we demonstrate that only APP overexpression reduced mitochondrial respiration, despite lower extracellular Aβ levels compared to BACE overexpression. Surprisingly, this could be rescued by a gamma secretase inhibitor, oppositionally indicating an Aβ-mediated mitochondrial toxicity. Analyzing Aβ localization revealed that intracellular levels of Aβ and an increased spatial association of APP/Aβ with mitochondria are associated with reduced mitochondrial respiration. Thus, our data provide marked evidence for a prominent role of intracellular Aβ accumulation in Alzheimer´s disease associated mitochondrial dysfunction. Thereby it highlights the importance of the localization of APP processing and intracellular transport as a decisive factor for mitochondrial function, linking two prominent hallmarks of neurodegenerative diseases. PMID:28005987

  8. Identification of a mitochondrial target of thiazolidinedione insulin sensitizers (mTOT--relationship to newly identified mitochondrial pyruvate carrier proteins.

    Directory of Open Access Journals (Sweden)

    Jerry R Colca

    Full Text Available Thiazolidinedione (TZD insulin sensitizers have the potential to effectively treat a number of human diseases, however the currently available agents have dose-limiting side effects that are mediated via activation of the transcription factor PPARγ. We have recently shown PPARγ-independent actions of TZD insulin sensitizers, but the molecular target of these molecules remained to be identified. Here we use a photo-catalyzable drug analog probe and mass spectrometry-based proteomics to identify a previously uncharacterized mitochondrial complex that specifically recognizes TZDs. These studies identify two well-conserved proteins previously known as brain protein 44 (BRP44 and BRP44 Like (BRP44L, which recently have been renamed Mpc2 and Mpc1 to signify their function as a mitochondrial pyruvate carrier complex. Knockdown of Mpc1 or Mpc2 in Drosophila melanogaster or pre-incubation with UK5099, an inhibitor of pyruvate transport, blocks the crosslinking of mitochondrial membranes by the TZD probe. Knockdown of these proteins in Drosophila also led to increased hemolymph glucose and blocked drug action. In isolated brown adipose tissue (BAT cells, MSDC-0602, a PPARγ-sparing TZD, altered the incorporation of (13C-labeled carbon from glucose into acetyl CoA. These results identify Mpc1 and Mpc2 as components of the mitochondrial target of TZDs (mTOT and suggest that understanding the modulation of this complex, which appears to regulate pyruvate entry into the mitochondria, may provide a viable target for insulin sensitizing pharmacology.

  9. Characterization of mitochondrial proteome in a severe case of ETF-QO deficiency.

    Science.gov (United States)

    Rocha, H; Ferreira, R; Carvalho, J; Vitorino, R; Santa, C; Lopes, L; Gregersen, N; Vilarinho, L; Amado, F

    2011-12-10

    Multiple acyl-CoA dehydrogenase deficiency (MADD) is a mitochondrial fatty acid oxidation disorder caused by mutations that affect electron transfer flavoprotein (ETF) or ETF:ubiquinone oxidoreductase (ETF-QO) or even due to unidentified disturbances of riboflavin metabolism. Besides all the available data on the molecular basis of FAO disorders, including MADD, the pathophysiological mechanisms underlying clinical phenotype development, namely at the mitochondrial level, are poorly understood. In order to contribute to the elucidation of these mechanisms, we isolated mitochondria from cultured fibroblasts, from a patient with a severe MADD presentation due to ETF-QO deficiency, characterize its mitochondrial proteome and compare it with normal controls. The used approach (2-DE-MS/MS) allowed the positive identification of 287 proteins in both patient and controls, presenting 35 of the significant differences in their relative abundance. Among the differentially expressed are proteins associated to binding/folding functions, mitochondrial antioxidant enzymes as well as proteins associated to apoptotic events. The overexpression of chaperones like Hsp60 or mitochondrial Grp75, antioxidant enzymes and apoptotic proteins reflects the mitochondrial response to a complete absence of ETF-QO. Our study provides a global perspective of the mitochondrial proteome plasticity in a severe case of MADD and highlights the main molecular pathways involved in its pathogenesis. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. The role of p38 in mitochondrial respiration in male and female mice.

    Science.gov (United States)

    Ju, Xiaohua; Wen, Yi; Metzger, Daniel; Jung, Marianna

    2013-06-07

    p38 is a mitogen-activated protein kinase and mediates cell growth, cell differentiation, and synaptic plasticity. The aim of this study is to determine the extent to which p38 plays a role in maintaining mitochondrial respiration in male and female mice under a normal condition. To achieve this aim, we have generated transgenic mice that lack p38 in cerebellar Purkinje neurons by crossing Pcp2 (Purkinje cell protein 2)-Cre mice with p38(loxP/loxP) mice. Mitochondria from cerebellum were then isolated from the transgenic and wild-type mice to measure mitochondrial respiration using XF24 respirometer. The mRNA and protein expression of cytochrome c oxidase (COX) in cerebellum were also measured using RT-PCR and immunoblot methods. Separately, HT22 cells were used to determine the involvement of 17β-estradiol (E2) and COX in mitochondrial respiration. The genetic knockout of p38 in Purkinje neurons suppressed the mitochondrial respiration only in male mice and increased COX expression only in female mice. The inhibition of COX by sodium azide (SA) sharply suppressed mitochondrial respiration of HT22 cells in a manner that was protected by E2. These data suggest that p38 is required for the mitochondrial respiration of male mice. When p38 is below a normal level, females may maintain mitochondrial respiration through COX up-regulation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Mitochondrial impairment by PPAR agonists and statins identified via immunocaptured OXPHOS complex activities and respiration

    International Nuclear Information System (INIS)

    Nadanaciva, Sashi; Dykens, James A.; Bernal, Autumn; Capaldi, Roderick A.; Will, Yvonne

    2007-01-01

    Mitochondrial impairment is increasingly implicated in the etiology of toxicity caused by some thiazolidinediones, fibrates, and statins. We examined the effects of members of these drug classes on respiration of isolated rat liver mitochondria using a phosphorescent oxygen sensitive probe and on the activity of individual oxidative phosphorylation (OXPHOS) complexes using a recently developed immunocapture technique. Of the six thiazolidinediones examined, ciglitazone, troglitazone, and darglitazone potently disrupted mitochondrial respiration. In accord with these data, ciglitazone and troglitazone were also potent inhibitors of Complexes II + III, IV, and V, while darglitazone predominantly inhibited Complex IV. Of the six statins evaluated, lovastatin, simvastatin, and cerivastatin impaired mitochondrial respiration the most, with simvastatin and lovastatin impairing multiple OXPHOS Complexes. Within the class of fibrates, gemfibrozil more potently impaired respiration than fenofibrate, clofibrate, or ciprofibrate. Gemfibrozil only modestly inhibited Complex I, fenofibrate inhibited Complexes I, II + III, and V, and clofibrate inhibited Complex V. Our findings with the two complementary methods indicate that (1) some members of each class impair mitochondrial respiration, whereas others have little or no effect, and (2) the rank order of mitochondrial impairment accords with clinical adverse events observed with these drugs. Since the statins are frequently co-prescribed with the fibrates or thiazolidinediones, various combinations of these three drug classes were also analyzed for their mitochondrial effects. In several cases, the combination additively uncoupled or inhibited respiration, suggesting that some combinations are more likely to yield clinically relevant drug-induced mitochondrial side effects than others

  12. Endogenous ovarian hormones affect mitochondrial efficiency in cerebral endothelium via distinct regulation of PGC-1 isoforms.

    Science.gov (United States)

    Kemper, Martin F; Zhao, Yuanzi; Duckles, Sue P; Krause, Diana N

    2013-01-01

    Mitochondria support the energy-intensive functions of brain endothelium but also produce damaging-free radicals that lead to disease. Previously, we found that estrogen treatment protects cerebrovascular mitochondria, increasing capacity for ATP production while decreasing reactive oxygen species (ROS). To determine whether these effects occur specifically in endothelium in vivo and also explore underlying transcriptional mechanisms, we studied freshly isolated brain endothelial preparations from intact and ovariectomized female mice. This preparation reflects physiologic influences of circulating hormones, hemodynamic forces, and cell-cell interactions of the neurovascular unit. Loss of ovarian hormones affected endothelial expression of the key mitochondrial regulator family, peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1), but in a unique way. Ovariectomy increased endothelial PGC-1α mRNA but decreased PGC-1β mRNA. The change in PGC-1β correlated with decreased mRNA for crucial downstream mitochondrial regulators, nuclear respiratory factor 1 and mitochondrial transcription factor A, as well as for ATP synthase and ROS protection enzymes, glutamate-cysteine ligase and manganese superoxide dismutase. Ovariectomy also decreased mitochondrial biogenesis (mitochondrial/nuclear DNA ratio). These results indicate ovarian hormones normally act through a distinctive regulatory pathway involving PGC-1β to support cerebral endothelial mitochondrial content and guide mitochondrial function to favor ATP coupling and ROS protection.

  13. Polyethylenimine-mediated impairment of mitochondrial membrane potential, respiration and membrane integrity

    DEFF Research Database (Denmark)

    Larsen, Anna Karina; Malinska, Dominika; Koszela-Piotrowska, Izabela

    2012-01-01

    The 25 kDa branched polyethylenimine (PEI) is a highly efficient synthetic polycation used in transfection protocols, but also triggers mitochondrial-mediated apoptotic cell death processes where the mechanistic issues are poorly understood. We now demonstrate that PEI in a concentration- and time......-dependent manner can affect functions (membrane potential, swelling and respiration) and ultrastructural integrity of freshly isolated rat liver mitochondria. The threshold concentration for detection of PEI-mediated impairment of rat liver mitochondrial functions is 3 µg/mL, however, lower PEI levels still exert...... some effects on mitochondrial morphology and respiration, and these may be related to the inherent membrane perturbing properties of this polycation. The PEI-mediated mitochondrial swelling phase is biphasic, with a fast decaying initial period (most prominent from 4 µg/mL PEI) followed by a slower...

  14. Mitochondrial role in cell aging

    Science.gov (United States)

    Miquel, J.; Fleming, J.; Economos, A. C.; Johnson, J. E., Jr.

    1980-01-01

    The experimental studies on the mitochondria of insect and mammalian cells are examined with a view to an analysis of intrinsic mitochondrial senescence, and its relation to the age-related changes in other cell organelles. The fine structural and biochemical data support the concept that the mitochondria of fixed postmitotic cells may be the site of intrinsic aging because of the attack by free radicals and lipid peroxides originating in the organelles as a by-product of oxygen reduction during respiration. Although the cells have numerous mechanisms for counteracting lipid peroxidation injury, there is a slippage in the antioxidant protection. Intrinsic mitochondrial aging could thus be considered as a specific manifestation of oxygen toxicity. It is proposed that free radical injury renders an increasing number of the mitochondria unable to divide, probably because of damage to the lipids of the inner membrane and to mitochondrial DNA.

  15. Redox Regulation of Mitochondrial Function

    Science.gov (United States)

    Handy, Diane E.

    2012-01-01

    Abstract Redox-dependent processes influence most cellular functions, such as differentiation, proliferation, and apoptosis. Mitochondria are at the center of these processes, as mitochondria both generate reactive oxygen species (ROS) that drive redox-sensitive events and respond to ROS-mediated changes in the cellular redox state. In this review, we examine the regulation of cellular ROS, their modes of production and removal, and the redox-sensitive targets that are modified by their flux. In particular, we focus on the actions of redox-sensitive targets that alter mitochondrial function and the role of these redox modifications on metabolism, mitochondrial biogenesis, receptor-mediated signaling, and apoptotic pathways. We also consider the role of mitochondria in modulating these pathways, and discuss how redox-dependent events may contribute to pathobiology by altering mitochondrial function. Antioxid. Redox Signal. 16, 1323–1367. PMID:22146081

  16. Genetics of mitochondrial dysfunction and infertility.

    Science.gov (United States)

    Demain, L A M; Conway, G S; Newman, W G

    2017-02-01

    Increasingly, mitochondria are being recognized as having an important role in fertility. Indeed in assisted reproductive technologies mitochondrial function is a key indicator of sperm and oocyte quality. Here, we review the literature regarding mitochondrial genetics and infertility. In many multisystem disorders caused by mitochondrial dysfunction death occurs prior to sexual maturity, or the clinical features are so severe that infertility may be underreported. Interestingly, many of the genes linked to mitochondrial dysfunction and infertility have roles in the maintenance of mitochondrial DNA or in mitochondrial translation. Studies on populations with genetically uncharacterized infertility have highlighted an association with mitochondrial DNA deletions, whether this is causative or indicative of poor functioning mitochondria requires further examination. Studies on the impact of mitochondrial DNA variants present conflicting data but highlight POLG as a particularly interesting candidate gene for both male and female infertility. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Mitochondrial DNA and Cancer Epidemiology Workshop

    Science.gov (United States)

    A workshop to review the state-of-the science in the mitochondrial DNA field and its use in cancer epidemiology, and to develop a concept for a research initiative on mitochondrial DNA and cancer epidemiology.

  18. Comparative transcriptional and translational analysis of leptospiral outer membrane protein expression in response to temperature.

    Science.gov (United States)

    Lo, Miranda; Cordwell, Stuart J; Bulach, Dieter M; Adler, Ben

    2009-12-08

    Leptospirosis is a global zoonosis affecting millions of people annually. Transcriptional changes in response to temperature were previously investigated using microarrays to identify genes potentially expressed upon host entry. Past studies found that various leptospiral outer membrane proteins are differentially expressed at different temperatures. However, our microarray studies highlighted a divergence between protein abundance and transcript levels for some proteins. Given the abundance of post-transcriptional expression control mechanisms, this finding highlighted the importance of global protein analysis systems. To complement our previous transcription study, we evaluated differences in the proteins of the leptospiral outer membrane fraction in response to temperature upshift. Outer membrane protein-enriched fractions from Leptospira interrogans grown at 30 degrees C or overnight upshift to 37 degrees C were isolated and the relative abundance of each protein was determined by iTRAQ analysis coupled with two-dimensional liquid chromatography and tandem mass spectrometry (2-DLC/MS-MS). We identified 1026 proteins with 99% confidence; 27 and 66 were present at elevated and reduced abundance respectively. Protein abundance changes were compared with transcriptional differences determined from the microarray studies. While there was some correlation between the microarray and iTRAQ data, a subset of genes that showed no differential expression by microarray was found to encode temperature-regulated proteins. This set of genes is of particular interest as it is likely that regulation of their expression occurs post-transcriptionally, providing an opportunity to develop hypotheses about the molecular dynamics of the outer membrane of Leptospira in response to changing environments. This is the first study to compare transcriptional and translational responses to temperature shift in L. interrogans. The results thus provide an insight into the mechanisms used by L

  19. Diglycolic acid, the toxic metabolite of diethylene glycol, chelates calcium and produces renal mitochondrial dysfunction in vitro.

    Science.gov (United States)

    Conrad, Taylor; Landry, Greg M; Aw, Tak Yee; Nichols, Royce; McMartin, Kenneth E

    2016-07-01

    Diethylene glycol (DEG) has caused many cases of acute kidney injury and deaths worldwide. Diglycolic acid (DGA) is the metabolite responsible for the renal toxicity, but its toxic mechanism remains unclear. To characterize the mitochondrial dysfunction produced from DGA by examining several mitochondrial processes potentially contributing to renal cell toxicity. The effect of DGA on mitochondrial membrane potential was examined in normal human proximal tubule (HPT) cells. Isolated rat kidney mitochondria were used to assess the effects of DGA on mitochondrial function, including respiratory parameters (States 3 and 4), electron transport chain complex activities and calcium-induced opening of the mitochondrial permeability transition pore. DGA was compared with ethylene glycol tetraacetic acid (EGTA) to determine calcium chelating ability. DGA cytotoxicity was assessed using lactate dehydrogenase leakage from cultured proximal tubule cells. DGA decreased the mitochondrial membrane potential in HPT cells. In rat kidney mitochondria, DGA decreased State 3 respiration, but did not affect State 4 respiration or the ADP/O ratio. DGA reduced glutamate/malate respiration at lower DGA concentrations (0.5 mmol/L) than succinate respiration (100 mmol/L). DGA inhibited Complex II activity without altering Complex I, III or IV activities. DGA blocked calcium-induced mitochondrial swelling, indicating inhibition of the calcium-dependent mitochondrial permeability transition. DGA and EGTA reduced the free calcium concentration in solution in an equimolar manner. DGA toxicity and mitochondrial dysfunction occurred as similar concentrations. DGA inhibited mitochondrial respiration, but without uncoupling oxidative phosphorylation. The more potent effect of DGA on glutamate/malate respiration and the inhibition of mitochondrial swelling was likely due to its chelation of calcium. These results indicate that DGA produces mitochondrial dysfunction by chelating calcium to

  20. Common effects of lithium and valproate on mitochondrial functions: protection against methamphetamine-induced mitochondrial damage

    OpenAIRE

    Bachmann, Rosilla F.; Wang, Yun; Yuan, Peixiong; Zhou, Rulun; Li, Xiaoxia; Alesci, Salvatore; Du, Jing; Manji, Husseini K.

    2009-01-01

    Accumulating evidence suggests that mitochondrial dysfunction plays a critical role in the progression of a variety of neurodegenerative and psychiatric disorders. Thus, enhancing mitochondrial function could potentially help ameliorate the impairments of neural plasticity and cellular resilience associated with a variety of neuropsychiatric disorders. A series of studies was undertaken to investigate the effects of mood stabilizers on mitochondrial function, and against mitochondrially media...

  1. Human C4orf14 interacts with the mitochondrial nucleoid and is involved in the biogenesis of the small mitochondrial ribosomal subunit.

    Science.gov (United States)

    He, J; Cooper, H M; Reyes, A; Di Re, M; Kazak, L; Wood, S R; Mao, C C; Fearnley, I M; Walker, J E; Holt, I J

    2012-07-01

    The bacterial homologue of C4orf14, YqeH, has been linked to assembly of the small ribosomal subunit. Here, recombinant C4orf14 isolated from human cells, co-purified with the small, 28S subunit of the mitochondrial ribosome and the endogenous protein co-fractionated with the 28S subunit in sucrose gradients. Gene silencing of C4orf14 specifically affected components of the small subunit, leading to decreased protein synthesis in the organelle. The GTPase of C4orf14 was critical to its interaction with the 28S subunit, as was GTP. Therefore, we propose that C4orf14, with bound GTP, binds to components of the 28S subunit facilitating its assembly, and GTP hydrolysis acts as the release mechanism. C4orf14 was also found to be associated with human mitochondrial nucleoids, and C4orf14 gene silencing caused mitochondrial DNA depletion. In vitro C4orf14 is capable of binding to DNA. The association of C4orf14 with mitochondrial translation factors and the mitochondrial nucleoid suggests that the 28S subunit is assembled at the mitochondrial nucleoid, enabling the direct transfer of messenger RNA from the nucleoid to the ribosome in the organelle.

  2. Obesity-induced down-regulation of the mitochondrial translocator protein (TSPO) impairs placental steroid production.

    Science.gov (United States)

    Lassance, Luciana; Haghiac, Maricela; Minium, Judi; Catalano, Patrick; Hauguel-de Mouzon, Sylvie

    2015-01-01

    Low concentrations of estradiol and progesterone are hallmarks of adverse pregnancy outcomes as is maternal obesity. During pregnancy, placental cholesterol is the sole source of sex steroids. Cholesterol trafficking is the limiting step in sex steroid biosynthesis and is mainly mediated by the translocator protein (TSPO), present in the mitochondrial outer membrane. The objective of the study was to investigate the effects of maternal obesity in placental sex steroid biosynthesis and TSPO regulation. One hundred forty-four obese (body mass index 30-35 kg/m(2)) and 90 lean (body mass index 19-25 kg/m(2)) pregnant women (OP and LP, respectively) recruited at scheduled term cesarean delivery. Placenta and maternal blood were collected. This study was conducted at MetroHealth Medical Center (Cleveland, Ohio). Maternal metabolic components (fasting glucose, insulin, leptin, estradiol, progesterone, and total cholesterol) and placental weight were measured. Placenta (mitochondria and membranes separated) and cord blood cholesterol values were verified. The expression and regulation of TSPO and mitochondrial function were analyzed. Plasma estradiol and progesterone concentrations were significantly lower (P < .04) in OP as compared with LP women. Maternal and cord plasma cholesterol were not different between groups. Placental citrate synthase activity and mitochondrial DNA, markers of mitochondrial density, were unchanged, but the mitochondrial cholesterol concentrations were 40% lower in the placenta of OP. TSPO gene and protein expressions were decreased 2-fold in the placenta of OP. In vitro trophoblast activation of the innate immune pathways with lipopolysaccharide and long-chain saturated fatty acids reduced TSPO expression by 2- to 3-fold (P < .05). These data indicate that obesity in pregnancy impairs mitochondrial steroidogenic function through the negative regulation of mitochondrial TSPO.

  3. Mitochondrial quality control in cardiac diseases.

    Directory of Open Access Journals (Sweden)

    Juliane Campos

    2016-10-01

    Full Text Available Disruption of mitochondrial homeostasis is a hallmark of cardiac diseases. Therefore, maintenance of mitochondrial integrity through different surveillance mechanisms is critical for cardiomyocyte survival. In this review, we discuss the most recent findings on the central role of mitochondrial quality control processes including regulation of mitochondrial redox balance, aldehyde metabolism, proteostasis, dynamics and clearance in cardiac diseases, highlighting their potential as therapeutic targets.

  4. Mitochondrial fusion through membrane automata.

    Science.gov (United States)

    Giannakis, Konstantinos; Andronikos, Theodore

    2015-01-01

    Studies have shown that malfunctions in mitochondrial processes can be blamed for diseases. However, the mechanism behind these operations is yet not sufficiently clear. In this work we present a novel approach to describe a biomolecular model for mitochondrial fusion using notions from the membrane computing. We use a case study defined in BioAmbient calculus and we show how to translate it in terms of a P automata variant. We combine brane calculi with (mem)brane automata to produce a new scheme capable of describing simple, realistic models. We propose the further use of similar methods and the test of other biomolecular models with the same behaviour.

  5. Effect of remifentanil on mitochondrial oxygen consumption of cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Siamak Djafarzadeh

    Full Text Available During sepsis, liver dysfunction is common, and failure of mitochondria to effectively couple oxygen consumption with energy production has been described. In addition to sepsis, pharmacological agents used to treat septic patients may contribute to mitochondrial dysfunction. This study addressed the hypothesis that remifentanil interacts with hepatic mitochondrial oxygen consumption. The human hepatoma cell line HepG2 and their isolated mitochondria were exposed to remifentanil, with or without further exposure to tumor necrosis factor-α (TNF-α. Mitochondrial oxygen consumption was measured by high-resolution respirometry, Caspase-3 protein levels by Western blotting, and cytokine levels by ELISA. Inhibitory κBα (IκBα phosphorylation, measurement of the cellular ATP content and mitochondrial membrane potential in intact cells were analysed using commercial ELISA kits. Maximal cellular respiration increased after one hour of incubation with remifentanil, and phosphorylation of IκBα occurred, denoting stimulation of nuclear factor κB (NF-κB. The effect on cellular respiration was not present at 2, 4, 8 or 16 hours of incubation. Remifentanil increased the isolated mitochondrial respiratory control ratio of complex-I-dependent respiration without interfering with maximal respiration. Preincubation with the opioid receptor antagonist naloxone prevented a remifentanil-induced increase in cellular respiration. Remifentanil at 10× higher concentrations than therapeutic reduced mitochondrial membrane potential and ATP content without uncoupling oxygen consumption and basal respiration levels. TNF-α exposure reduced respiration of complex-I, -II and -IV, an effect which was prevented by prior remifentanil incubation. Furthermore, prior remifentanil incubation prevented TNF-α-induced IL-6 release of HepG2 cells, and attenuated fragmentation of pro-caspase-3 into cleaved active caspase 3 (an early marker of apoptosis. Our data suggest that

  6. Myocardial mitochondrial and contractile function are preserved in mice lacking adiponectin.

    Directory of Open Access Journals (Sweden)

    Martin Braun

    Full Text Available Adiponectin deficiency leads to increased myocardial infarct size following ischemia reperfusion and to exaggerated cardiac hypertrophy following pressure overload, entities that are causally linked to mitochondrial dysfunction. In skeletal muscle, lack of adiponectin results in impaired mitochondrial function. Thus, it was our objective to investigate whether adiponectin deficiency impairs mitochondrial energetics in the heart. At 8 weeks of age, heart weight-to-body weight ratios were not different between adiponectin knockout (ADQ-/- mice and wildtypes (WT. In isolated working hearts, cardiac output, aortic developed pressure and cardiac power were preserved in ADQ-/- mice. Rates of fatty acid oxidation, glucose oxidation and glycolysis were unchanged between groups. While myocardial oxygen consumption was slightly reduced (-24% in ADQ-/- mice in isolated working hearts, rates of maximal ADP-stimulated mitochondrial oxygen consumption and ATP synthesis in saponin-permeabilized cardiac fibers were preserved in ADQ-/- mice with glutamate, pyruvate or palmitoyl-carnitine as a substrate. In addition, enzymatic activity of respiratory complexes I and II was unchanged between groups. Phosphorylation of AMP-activated protein kinase and SIRT1 activity were not decreased, expression and acetylation of PGC-1α were unchanged, and mitochondrial content of OXPHOS subunits was not decreased in ADQ-/- mice. Finally, increasing energy demands due to prolonged subcutaneous infusion of isoproterenol did not differentially affect cardiac contractility or mitochondrial function in ADQ-/- mice compared to WT. Thus, mitochondrial and contractile function are preserved in hearts of mice lacking adiponectin, suggesting that adiponectin may be expendable in the regulation of mitochondrial energetics and contractile function in the heart under non-pathological conditions.

  7. Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

    Science.gov (United States)

    Kandel, Judith; Angelin, Alessia A; Wallace, Douglas C; Eckmann, David M

    2016-11-07

    An abundance of research suggests that cellular mitochondrial and cytoskeletal disruption are related, but few studies have directly investigated causative connections between the two. We previously demonstrated that inhibiting microtubule and microfilament polymerization affects mitochondrial motility on the whole-cell level in fibroblasts. Since mitochondrial motility can be indicative of mitochondrial function, we now further characterize the effects of these cytoskeletal inhibitors on mitochondrial potential, morphology and respiration. We found that although they did not reduce mitochondrial inner membrane potential, cytoskeletal toxins induced significant decreases in basal mitochondrial respiration. In some cases, basal respiration was only affected after cells were pretreated with the calcium ionophore A23187 in order to stress mitochondrial function. In most cases, mitochondrial morphology remained unaffected, but extreme microfilament depolymerization or combined intermediate doses of microtubule and microfilament toxins resulted in decreased mitochondrial lengths. Interestingly, these two particular exposures did not affect mitochondrial respiration in cells not sensitized with A23187, indicating an interplay between mitochondrial morphology and respiration. In all cases, inducing maximal respiration diminished differences between control and experimental groups, suggesting that reduced basal respiration originates as a largely elective rather than pathological symptom of cytoskeletal impairment. However, viability experiments suggest that even this type of respiration decrease may be associated with cell death.

  8. Mitochondrial Energy and Redox Signaling in Plants

    Science.gov (United States)

    Schwarzländer, Markus

    2013-01-01

    Abstract Significance: For a plant to grow and develop, energy and appropriate building blocks are a fundamental requirement. Mitochondrial respiration is a vital source for both. The delicate redox processes that make up respiration are affected by the plant's changing environment. Therefore, mitochondrial regulation is critically important to maintain cellular homeostasis. This involves sensing signals from changes in mitochondrial physiology, transducing this information, and mounting tailored responses, by either adjusting mitochondrial and cellular functions directly or reprogramming gene expression. Recent Advances: Retrograde (RTG) signaling, by which mitochondrial signals control nuclear gene expression, has been a field of very active research in recent years. Nevertheless, no mitochondrial RTG-signaling pathway is yet understood in plants. This review summarizes recent advances toward elucidating redox processes and other bioenergetic factors as a part of RTG signaling of plant mitochondria. Critical Issues: Novel insights into mitochondrial physiology and redox-regulation provide a framework of upstream signaling. On the other end, downstream responses to modified mitochondrial function have become available, including transcriptomic data and mitochondrial phenotypes, revealing processes in the plant that are under mitochondrial control. Future Directions: Drawing parallels to chloroplast signaling and mitochondrial signaling in animal systems allows to bridge gaps in the current understanding and to deduce promising directions for future research. It is proposed that targeted usage of new technical approaches, such as quantitative in vivo imaging, will provide novel leverage to the dissection of plant mitochondrial signaling. Antioxid. Redox Signal. 18, 2122–2144. PMID:23234467

  9. Mitochondrial mutations drive prostate cancer aggression

    DEFF Research Database (Denmark)

    Hopkins, Julia F.; Sabelnykova, Veronica Y.; Weischenfeldt, Joachim

    2017-01-01

    Nuclear mutations are well known to drive tumor incidence, aggression and response to therapy. By contrast, the frequency and roles of mutations in the maternally inherited mitochondrial genome are poorly understood. Here we sequence the mitochondrial genomes of 384 localized prostate cancer...... in prostate cancer, and suggest interplay between nuclear and mitochondrial mutational profiles in prostate cancer....

  10. LILBID-mass spectrometry of the mitochondrial preprotein translocase TOM

    International Nuclear Information System (INIS)

    Mager, Frauke; Lintzel, Julia; Nussberger, Stephan; Sokolova, Lucie; Brutschy, Bernhard

    2010-01-01

    In the present work we applied a novel mass spectrometry method termed laser-induced liquid bead ion desorption mass spectrometry (LILBID-MS) to the outer mitochondrial membrane protein translocon TOM to analyze its subunit composition and stoichiometry. With TOM core complex, purified at high pH, we demonstrate that a TOM core complex of Neurospora crassa is composed of at least two Tom40 and Tom22 molecules, respectively, and more than five small Tom subunits between 5.5 and 6.4 kDa. We show that the multiprotein complex has a total molecular mass higher than 170 depending on the number of Tom5, Tom6 and Tom7 molecules bound.

  11. LILBID-mass spectrometry of the mitochondrial preprotein translocase TOM

    Science.gov (United States)

    Mager, Frauke; Sokolova, Lucie; Lintzel, Julia; Brutschy, Bernhard; Nussberger, Stephan

    2010-11-01

    In the present work we applied a novel mass spectrometry method termed laser-induced liquid bead ion desorption mass spectrometry (LILBID-MS) to the outer mitochondrial membrane protein translocon TOM to analyze its subunit composition and stoichiometry. With TOM core complex, purified at high pH, we demonstrate that a TOM core complex of Neurospora crassa is composed of at least two Tom40 and Tom22 molecules, respectively, and more than five small Tom subunits between 5.5 and 6.4 kDa. We show that the multiprotein complex has a total molecular mass higher than 170 depending on the number of Tom5, Tom6 and Tom7 molecules bound.

  12. Probes of the Mitochondrial cAMP-dependent Protein Kinase

    Science.gov (United States)

    Shell, Jennifer R.; Lawrence, David S.

    2013-01-01

    The development of a fluorescent assay to detect activity of the mitochondrial cAMP-dependent protein kinase (PKA) is described. A peptide-based sensor was utilized to quantify the relative amount of PKA activity present in each compartment of the mitochondria (the outer membrane, the intermembrane space, and the matrix). In the process of validating this assay, we discovered that PKA activity is regulated by the protease calpain. Upon exposure of bovine heart mitochondria to digitonin, Ca2+, and a variety of electron transport chain inhibitors, the regulatory subunits of the PKA holoenzyme (R2C2) are digested, releasing active catalytic subunits. This proteolysis is attenuated by calpain inhibitor I (ALLN). PMID:23410952

  13. The mitochondrial genome of the entomoparasitic green alga helicosporidium.

    Directory of Open Access Journals (Sweden)

    Jean-François Pombert

    Full Text Available BACKGROUND: Helicosporidia are achlorophyllous, non-photosynthetic protists that are obligate parasites of invertebrates. Highly specialized, these pathogens feature an unusual cyst stage that dehisces inside the infected organism and releases a filamentous cell displaying surface projections, which will penetrate the host gut wall and eventually reproduce in the hemolymph. Long classified as incertae sedis or as relatives of other parasites such as Apicomplexa or Microsporidia, the Helicosporidia were surprisingly identified through molecular phylogeny as belonging to the Chlorophyta, a phylum of green algae. Most phylogenetic analyses involving Helicosporidia have placed them within the subgroup Trebouxiophyceae and further suggested a close affiliation between the Helicosporidia and the genus Prototheca. Prototheca species are also achlorophyllous and pathogenic, but they infect vertebrate hosts, inducing protothecosis in humans. The complete plastid genome of an Helicosporidium species was recently described and is a model of compaction and reduction. Here we describe the complete mitochondrial genome sequence of the same strain, Helicosporidium sp. ATCC 50920 isolated from the black fly Simulium jonesi. METHODOLOGY/PRINCIPAL FINDINGS: The circular mapping 49343 bp mitochondrial genome of Helicosporidium closely resembles that of the vertebrate parasite Prototheca wickerhamii. The two genomes share an almost identical gene complement and display a level of synteny that is higher than any other sequenced chlorophyte mitochondrial DNAs. Interestingly, the Helicosporidium mtDNA feature a trans-spliced group I intron, and a second group I intron that contains two open reading frames that appear to be degenerate maturase/endonuclease genes, both rare characteristics for this type of intron. CONCLUSIONS/SIGNIFICANCE: The architecture, genome content, and phylogeny of the Helicosporidium mitochondrial genome are all congruent with its close

  14. 46 CFR 154.170 - Outer hull steel plating.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Outer hull steel plating. 154.170 Section 154.170... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Hull Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the...

  15. Outer space and nuclear deterrence: problems and prospects

    International Nuclear Information System (INIS)

    Gasparini Alves, P.

    1993-01-01

    The presentation deals with the role of outer-space applications and prospects for near future developments in nuclear deterrence. Outer space capabilities of United Sates, Russian Federation, Belarus, Kazakhstan, Ukraine, China, and United Kingdom as well as other states are analyzed. Conceptual problems of offensive and defensive doctrines are reviewed together with legal implications

  16. Long-Lived Glass Mirrors For Outer Space

    Science.gov (United States)

    Bouquet, Frank L.; Maag, Carl R.; Heggen, Philip M.

    1988-01-01

    Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.

  17. Newborns' Face Recognition: Role of Inner and Outer Facial Features

    Science.gov (United States)

    Turati, Chiara; Macchi Cassia, Viola; Simion, Francesca; Leo, Irene

    2006-01-01

    Existing data indicate that newborns are able to recognize individual faces, but little is known about what perceptual cues drive this ability. The current study showed that either the inner or outer features of the face can act as sufficient cues for newborns' face recognition (Experiment 1), but the outer part of the face enjoys an advantage…

  18. Using Förster-Resonance Energy Transfer to Measure Protein Interactions Between Bcl-2 Family Proteins on Mitochondrial Membranes.

    Science.gov (United States)

    Pogmore, Justin P; Pemberton, James M; Chi, Xiaoke; Andrews, David W

    2016-01-01

    The Bcl-2 family of proteins regulates the process of mitochondrial outer membrane permeabilization, causing the release of cytochrome c and committing a cell to apoptosis. The majority of the functional interactions between these proteins occur at, on, or within the mitochondrial outer membrane, complicating structural studies of the proteins and complexes. As a result most in vitro studies of these protein-protein interactions use truncated proteins and/or detergents which can cause artificial interactions. Herein, we describe a detergent-free, fluorescence-based, in vitro technique to study binding between full-length recombinant Bcl-2 family proteins, particularly cleaved BID (cBID) and BCL-XL, on the membranes of purified mitochondria.

  19. Zinc-dependent multi-conductance channel activity in mitochondria isolated from ischemic brain.

    Science.gov (United States)

    Bonanni, Laura; Chachar, Mushtaque; Jover-Mengual, Teresa; Li, Hongmei; Jones, Adrienne; Yokota, Hidenori; Ofengeim, Dimitry; Flannery, Richard J; Miyawaki, Takahiro; Cho, Chang-Hoon; Polster, Brian M; Pypaert, Marc; Hardwick, J Marie; Sensi, Stefano L; Zukin, R Suzanne; Jonas, Elizabeth A

    2006-06-21

    Transient global ischemia is a neuronal insult that induces delayed cell death. A hallmark event in the early post-ischemic period is enhanced permeability of mitochondrial membranes. The precise mechanisms by which mitochondrial function is disrupted are, as yet, unclear. Here we show that global ischemia promotes alterations in mitochondrial membrane contact points, a rise in intramitochondrial Zn2+, and activation of large, multi-conductance channels in mitochondrial outer membranes by 1 h after insult. Mitochondrial channel activity was associated with enhanced protease activity and proteolytic cleavage of BCL-xL to generate its pro-death counterpart, deltaN-BCL-xL. The findings implicate deltaN-BCL-xL in large, multi-conductance channel activity. Consistent with this, large channel activity was mimicked by introduction of recombinant deltaN-BCL-xL to control mitochondria and blocked by introduction of a functional BCL-xL antibody to post-ischemic mitochondria via the patch pipette. Channel activity was also inhibited by nicotinamide adenine dinucleotide, indicative of a role for the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. In vivo administration of the membrane-impermeant Zn2+ chelator CaEDTA before ischemia or in vitro application of the membrane-permeant Zn2+ chelator tetrakis-(2-pyridylmethyl) ethylenediamine attenuated channel activity, suggesting a requirement for Zn2+. These findings reveal a novel mechanism by which ischemic insults disrupt the functional integrity of the outer mitochondrial membrane and implicate deltaN-BCL-xL and VDAC in the large, Zn2+-dependent mitochondrial channels observed in post-ischemic hippocampal mitochondria.

  20. Insulin Resistance and Mitochondrial Dysfunction.

    Science.gov (United States)

    Gonzalez-Franquesa, Alba; Patti, Mary-Elizabeth

    2017-01-01

    Insulin resistance precedes and predicts the onset of type 2 diabetes (T2D) in susceptible humans, underscoring its important role in the complex pathogenesis of this disease. Insulin resistance contributes to multiple tissue defects characteristic of T2D, including reduced insulin-stimulated glucose uptake in insulin-sensitive tissues, increased hepatic glucose production, increased lipolysis in adipose tissue, and altered insulin secretion. Studies of individuals with insulin resistance, both with established T2D and high-risk individuals, have consistently demonstrated a diverse array of defects in mitochondrial function (i.e., bioenergetics, biogenesis and dynamics). However, it remains uncertain whether mitochondrial dysfunction is primary (critical initiating defect) or secondary to the subtle derangements in glucose metabolism, insulin resistance, and defective insulin secretion present early in the course of disease development. In this chapter, we will present the evidence linking mitochondrial dysfunction and insulin resistance, and review the potential for mitochondrial targets as a therapeutic approach for T2D.

  1. Renal disease and mitochondrial genetics.

    Science.gov (United States)

    Rötig, Agnès

    2003-01-01

    Respiratory chain (RC) deficiencies have long been regarded as neuromuscular diseases mainly originating from mutations in the mitochondrial DNA. Oxidative phosphorylation, i.e. adenosine triphosphate (ATP) synthesis-coupled electron transfer from substrate to oxygen through the RC, does not occur only in the neuromuscular system. Therefore, a RC deficiency can theoretically give rise to any symptom, in any organ or tissue, at any age and with any mode of inheritance, owing to the dual genetic origin of RC enzymes (nuclear DNA and mitochondrial DNA). Mitochondrial diseases can give rise to various syndromes or association, namely, neurologic and neuromuscular diseases, cardiac, renal, hepatic, hematological and endocrin or dermatological presentations. The most frequent renal symptom is proximal tubular dysfunction with a more or less complete de Toni-Debre-Fanconi Syndrome. A few patients have been reported with tubular acidosis, Bartter Syndrome, chronic tubulointerstitial nephritis or nephrotic syndrome. The diagnosis of a RC deficiency is difficult when only renal symptoms are present, but should be easier when another, seemingly unrelated symptom is observed. Metabolic screening for abnormal oxidoreduction status in plasma, including lactate/pyruvate and ketone body molar ratios, can help to identify patients for further investigations. These include the measurement of oxygen consumption by mitochondria and the assessment of mitochondrial respiratory enzyme activities by spectrophotometric studies. Any mode of inheritance can be observed: sporadic, autosomal dominant or recessive, or maternal inheritance.

  2. Mitochondrial function, ornamentation, and immunocompetence.

    Science.gov (United States)

    Koch, Rebecca E; Josefson, Chloe C; Hill, Geoffrey E

    2017-08-01

    Understanding the mechanisms that link ornamental displays and individual condition is key to understanding the evolution and function of ornaments. Immune function is an aspect of individual quality that is often associated with the expression of ornamentation, but a general explanation for why the expression of some ornaments seems to be consistently linked to immunocompetence remains elusive. We propose that condition-dependent ornaments may be linked to key aspects of immunocompetence through co-dependence on mitochondrial function. Mitochondrial involvement in immune function is rarely considered outside of the biomedical literature, but the role of mitochondria as the primary energy producers of the cell and the centres of biosynthesis, the oxidative stress response, and cellular signalling place them at the hub of a variety of immune pathways. A promising new mechanistic explanation for correlations between a wide range of ornamental traits and the properties of individual quality is that mitochondrial function may be the 'shared pathway' responsible for links between ornament production and individual condition. Herein, we first review the role of mitochondria as both signal transducers and metabolic regulators of immune function. We then describe connections between hormonal pathways and mitochondria, with implications for both immune function and the expression of ornamentation. Finally, we explore the possibility that ornament expression may link directly to mitochondrial function. Considering condition-dependent traits within the framework of mitochondrial function has the potential to unify central tenets within the study of sexual selection, eco-immunology, oxidative stress ecology, stress and reproductive hormone biology, and animal physiology. © 2016 Cambridge Philosophical Society.

  3. Mitochondrial rejuvenation after induced pluripotency.

    Directory of Open Access Journals (Sweden)

    Steven T Suhr

    2010-11-01

    Full Text Available As stem cells of the early embryo mature and differentiate into all tissues, the mitochondrial complement undergoes dramatic functional improvement. Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands. It has recently been reported that when the stem cell type known as induced pluripotent stem cells (IPSCs are re-differentiated for several weeks in vitro, the mitochondrial complement progressively re-acquires properties approximating input fibroblasts, suggesting that despite the observation that IPSC conversion "resets" some parameters of cellular aging such as telomere length, it may have little impact on other age-affected cellular systems such as mitochondria in IPSC-derived cells.We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts. This observation likely stems from two aspects of our experimental design: 1 that the input cell lines used were of advanced cellular age and contained an inefficient mitochondrial complement, and 2 the re-derived fibroblasts were produced using an extensive differentiation regimen that may more closely mimic the degree of growth and maturation found in a developing mammal.These results - coupled with earlier data from our laboratory - suggest that IPSC conversion not only resets the "biological clock", but can also rejuvenate the energetic capacity of derived cells.

  4. Genetic polymorphisms of Echinococcus tapeworms in China as determined by mitochondrial and nuclear DNA sequences ✩

    Science.gov (United States)

    Nakao, Minoru; Li, Tiaoying; Han, Xiumin; Ma, Xiumin; Xiao, Ning; Qiu, Jiamin; Wang, Hu; Yanagida, Tetsuya; Mamuti, Wulamu; Wen, Hao; Moro, Pedro L.; Giraudoux, Patrick; Craig, Philip S.; Ito, Akira

    2009-01-01

    The genetic polymorphisms of Echinococcus spp. in the eastern Tibetan Plateau and the Xinjiang Uyghur Autonomous Region were evaluated by DNA sequencing analyses of genes for mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear elongation factor-1 alpha (ef1a). We collected 68 isolates of Echinococcus granulosus sensu stricto (s.s.) from Xinjiang and 113 isolates of E. granulosus s. s., 49 isolates of Echinococcus multilocularis and 34 isolates of Echinococcus shiquicus from the Tibetan Plateau. The results of molecular identification by mitochondrial and nuclear markers were identical, suggesting the infrequency of introgressive hybridization. A considerable intraspecific variation was detected in mitochondrial cox1 sequences. The parsimonious network of cox1 haplotypes showed star-like features in E. granulosus s. s. and E. multilocularis, but a divergent feature in E. shiquicus. The cox1 neutrality indexes computed by Tajima's D and Fu's Fs tests showed high negative values in E. granulosus s. s. and E. multilocularis, indicating significant deviations from neutrality. In contrast, the low positive values of both tests were obtained in E. shiquicus. These results suggest the following hypotheses: (i) recent founder effects arose in E. granulosus and E. multilocularis after introducing particular individuals into the endemic areas by anthropogenic movement or natural migration of host mammals, and (ii) the ancestor of E. shiquicus was segregated into the Tibetan Plateau by colonizing alpine mammals and its mitochondrial locus has evolved without bottleneck effects. PMID:19800346

  5. A novel method for determining human ex vivo submaximal skeletal muscle mitochondrial function

    DEFF Research Database (Denmark)

    Hey-Mogensen, Martin; Gram, Martin; Jensen, Martin Borch

    2015-01-01

    previously used. Muscle biopsies were taken from 64 old or young male subjects (60-70 or 20-30 years old). Aged subjects were recruited as trained or untrained. Muscle biopsies were used for isolation of mitochondria and subsequent measurements of DNA repair, antioxidant capacity and mitochondrial protein...

  6. Phylogenetic Analysis of Phytophthora Species Based on Mitochondrial and Nuclear DNA Sequences

    NARCIS (Netherlands)

    Kroon, L.P.N.M.; Bakker, F.T.; Bosch, van den G.B.M.; Bonants, P.J.M.; Flier, W.G.

    2004-01-01

    A molecular phylogenetic analysis of the genus Phytophthora was performed, 113 isolates from 48 Phytophthora species were included in this analysis. Phylogenetic analyses were performed on regions of mitochondrial (cytochrome c oxidase subunit 1; NADH dehydrogenase subunit 1) and nuclear gene

  7. Characterization of the Respiration-Induced Yeast Mitochondrial Permeability Transition Pore

    OpenAIRE

    Bradshaw, Patrick C.; Pfeiffer, Douglas R.

    2013-01-01

    When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable throug...

  8. Repression of mitochondrial translation, respiration and a metabolic cycle-regulated gene, SLF1, by the yeast Pumilio-family protein Puf3p.

    Directory of Open Access Journals (Sweden)

    Marc Chatenay-Lapointe

    Full Text Available Synthesis and assembly of the mitochondrial oxidative phosphorylation (OXPHOS system requires genes located both in the nuclear and mitochondrial genomes, but how gene expression is coordinated between these two compartments is not fully understood. One level of control is through regulated expression mitochondrial ribosomal proteins and other factors required for mitochondrial translation and OXPHOS assembly, which are all products of nuclear genes that are subsequently imported into mitochondria. Interestingly, this cadre of genes in budding yeast has in common a 3'-UTR element that is bound by the Pumilio family protein, Puf3p, and is coordinately regulated under many conditions, including during the yeast metabolic cycle. Multiple functions have been assigned to Puf3p, including promoting mRNA degradation, localizing nucleus-encoded mitochondrial transcripts to the outer mitochondrial membrane, and facilitating mitochondria-cytoskeletal interactions and motility. Here we show that Puf3p has a general repressive effect on mitochondrial OXPHOS abundance, translation, and respiration that does not involve changes in overall mitochondrial biogenesis and largely independent of TORC1-mitochondrial signaling. We also identified the cytoplasmic translation factor Slf1p as yeast metabolic cycle-regulated gene that is repressed by Puf3p at the post-transcriptional level and promotes respiration and extension of yeast chronological life span when over-expressed. Altogether, these results should facilitate future studies on which of the many functions of Puf3p is most relevant for regulating mitochondrial gene expression and the role of nuclear-mitochondrial communication in aging and longevity.

  9. High Fat Diet-Induced Changes in Mouse Muscle Mitochondrial Phospholipids Do Not Impair Mitochondrial Respiration Despite Insulin Resistance

    Science.gov (United States)

    Hulshof, Martijn F. M.; van den Berg, Sjoerd A. A.; Schaart, Gert; van Dijk, Ko Willems; Smit, Egbert; Mariman, Edwin C. M.

    2011-01-01

    Background Type 2 diabetes mellitus and muscle insulin resistance have been associated with reduced capacity of skeletal muscle mitochondria, possibly as a result of increased intake of dietary fat. Here, we examined the hypothesis that a prolonged high-fat diet consumption (HFD) increases the saturation of muscle mitochondrial membrane phospholipids causing impaired mitochondrial oxidative capacity and possibly insulin resistance. Methodology C57BL/6J mice were fed an 8-week or 20-week low fat diet (10 kcal%; LFD) or HFD (45 kcal%). Skeletal muscle mitochondria were isolated and fatty acid (FA) composition of skeletal muscle mitochondrial phospholipids was analyzed by thin-layer chromatography followed by GC. High-resolution respirometry was used to assess oxidation of pyruvate and fatty acids by mitochondria. Insulin sensitivity was estimated by HOMA-IR. Principal Findings At 8 weeks, mono-unsaturated FA (16∶1n7, 18∶1n7 and 18∶1n9) were decreased (−4.0%, p<0.001), whereas saturated FA (16∶0) were increased (+3.2%, p<0.001) in phospholipids of HFD vs. LFD mitochondria. Interestingly, 20 weeks of HFD descreased mono-unsaturated FA while n-6 poly-unsaturated FA (18∶2n6, 20∶4n6, 22∶5n6) showed a pronounced increase (+4.0%, p<0.001). Despite increased saturation of muscle mitochondrial phospholipids after the 8-week HFD, mitochondrial oxidation of both pyruvate and fatty acids were similar between LFD and HFD mice. After 20 weeks of HFD, the increase in n-6 poly-unsaturated FA was accompanied by enhanced maximal capacity of the electron transport chain (+49%, p = 0.002) and a tendency for increased ADP-stimulated respiration, but only when fuelled by a lipid-derived substrate. Insulin sensitivity in HFD mice was reduced at both 8 and 20 weeks. Conclusions/Interpretation Our findings do not support the concept that prolonged HF feeding leads to increased saturation of skeletal muscle mitochondrial phospholipids resulting in a decrease in

  10. High fat diet-induced changes in mouse muscle mitochondrial phospholipids do not impair mitochondrial respiration despite insulin resistance.

    Directory of Open Access Journals (Sweden)

    Joris Hoeks

    Full Text Available BACKGROUND: Type 2 diabetes mellitus and muscle insulin resistance have been associated with reduced capacity of skeletal muscle mitochondria, possibly as a result of increased intake of dietary fat. Here, we examined the hypothesis that a prolonged high-fat diet consumption (HFD increases the saturation of muscle mitochondrial membrane phospholipids causing impaired mitochondrial oxidative capacity and possibly insulin resistance. METHODOLOGY: C57BL/6J mice were fed an 8-week or 20-week low fat diet (10 kcal%; LFD or HFD (45 kcal%. Skeletal muscle mitochondria were isolated and fatty acid (FA composition of skeletal muscle mitochondrial phospholipids was analyzed by thin-layer chromatography followed by GC. High-resolution respirometry was used to assess oxidation of pyruvate and fatty acids by mitochondria. Insulin sensitivity was estimated by HOMA-IR. PRINCIPAL FINDINGS: At 8 weeks, mono-unsaturated FA (16∶1n7, 18∶1n7 and 18∶1n9 were decreased (-4.0%, p<0.001, whereas saturated FA (16∶0 were increased (+3.2%, p<0.001 in phospholipids of HFD vs. LFD mitochondria. Interestingly, 20 weeks of HFD descreased mono-unsaturated FA while n-6 poly-unsaturated FA (18∶2n6, 20∶4n6, 22∶5n6 showed a pronounced increase (+4.0%, p<0.001. Despite increased saturation of muscle mitochondrial phospholipids after the 8-week HFD, mitochondrial oxidation of both pyruvate and fatty acids were similar between LFD and HFD mice. After 20 weeks of HFD, the increase in n-6 poly-unsaturated FA was accompanied by enhanced maximal capacity of the electron transport chain (+49%, p = 0.002 and a tendency for increased ADP-stimulated respiration, but only when fuelled by a lipid-derived substrate. Insulin sensitivity in HFD mice was reduced at both 8 and 20 weeks. CONCLUSIONS/INTERPRETATION: Our findings do not support the concept that prolonged HF feeding leads to increased saturation of skeletal muscle mitochondrial phospholipids resulting in a decrease in

  11. Analysis of long-chain fatty acid binding activity in vesicles of the outer membrane generated from Escherchia coli

    International Nuclear Information System (INIS)

    Black, P.N.

    1987-01-01

    Escherichia coli transports long-chain fatty acids across the dual membrane by a high affinity, saturable, energy-dependent process. The fadL gene codes for an outer membrane protein which appears to act specifically as a long-chain fatty acid binding protein when fatty acid utilization is blocked by mutation. In an effort to understand the function of the fadL gene product, FLP, membranes have been isolated from fadL + and fadL - strains following osmotic lysis. Following isolation, total membranes were separated into inner and outer membrane fractions and assayed for long-chain fatty acid binding activity. Outer membrane vesicles were incubated 2-5 min at 37 0 C with 3 H oleate (C/sub 18:1/), cooled to 0 0 C, and centrifuged through a Lipidex 100 column for 3 min to remove the unbound fatty acid. The level of fatty acid binding was quantitated by scintillation counting of the eluate. Outer membrane vesicles generated from a fadL + strain bind 325 pmol fatty acid/mg protein whereas vesicles generated for a mutant strain bind 175 pmol fatty acid/mg protein. These data suggest that FLP acts at least as a long-chain fatty acid binding protein on the surface of the cell

  12. Dioxin-induced acute cardiac mitochondrial oxidative damage and increased activity of ATP-sensitive potassium channels in Wistar rats

    International Nuclear Information System (INIS)

    Pereira, Susana P.; Pereira, Gonçalo C.; Pereira, Cláudia V.; Carvalho, Filipa S.; Cordeiro, Marília H.; Mota, Paula C.; Ramalho-Santos, João; Moreno, António J.; Oliveira, Paulo J.

    2013-01-01

    The environmental dioxin 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is classified as a Group 1 human carcinogen and teratogenic agent. We hypothesize that TCDD-induced oxidative stress may also interfere with mitochondrial ATP-sensitive potassium channels (mitoKATP), which are known to regulate and to be regulated by mitochondrial redox state. We investigated the effects of an acute treatment of male Wistar rats with TCDD (50 μg/kg i.p.) and measured the regulation of cardiac mitoKATP. While the function of cardiac mitochondria was slightly depressed, mitoKATP activity was 52% higher in animals treated with TCDD. The same effects were not observed in liver mitochondria isolated from the same animals. Our data also shows that regulation of mitochondrial ROS production by mitoKATP activity is different in both groups. To our knowledge, this is the first report to show that TCDD increases mitoKATP activity in the heart, which may counteract the increased oxidative stress caused by the dioxin during acute exposure. -- Highlights: •Acute TCDD treatment of Wistar rats causes cardiac oxidative stress. •Acute TCDD treatment causes cardiac mitochondrial alterations. •Mitochondrial liver vs. heart alterations are distinct. •TCDD treatment resulted in altered activity of cardiac mitochondrial K-ATP channels. -- Dioxin alters the regulation of cardiac mitochondrial ATP-sensitive potassium channels and disturbs mitochondrial physiology

  13. Prevention of an arms race in outer space

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The space age may be the to have begun in 1957, when for the first time a man-made object was lofted into orbit round the Earth. Since that date, the new problems of outer space have been discussed in the United Nations, particularly in the General Assembly, in the Committee on the Peaceful Uses of Outer Space and its subsidiary bodies, and in the Conference on Disarmament. The discussions have contributed to the conclusion of a number of international agreements concerning both military and peaceful aspects of the use of outer space. This paper reports that according to the 1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, known as the outer space Treaty, outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means (article II), and the parties undertake not to place in orbit around the earth any objects carrying nuclear weapons or any other kinds of weapons of ass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner (article IV). Detailed norms for States' actions in this environment are included in the 1979 Agreement Governing the Activities of States on the Moon and other Celestial Bodies to ensure that the Moon and other celestial bodies within the solar system, other than Earth, are used exclusively for peaceful purposes

  14. Changes in mitochondrial electron transport chain activity during insect metamorphosis.

    Science.gov (United States)

    Chamberlin, M E

    2007-02-01

    The midgut of the tobacco hornworm (Manduca sexta) is a highly aerobic tissue that is destroyed by programmed cell death during larval-pupal metamorphosis. The death of the epithelium begins after commitment to pupation, and the oxygen consumption of isolated midgut mitochondria decreases soon after commitment. To assess the role of the electron transport chain in this decline in mitochondrial function, the maximal activities of complexes I-IV of the respiratory chain were measured in isolated midgut mitochondria. Whereas there were no developmental changes in the activity of complex I or III, activities of complexes II and IV [cytochrome c oxidase (COX)] were higher in mitochondria from precommitment than postcommitment larvae. This finding is consistent with a higher rate of succinate oxidation in mitochondria isolated from precommitment larvae and reveals that the metamorphic decline in mitochondrial respiration is due to the targeted destruction or inactivation of specific sites within the mitochondria, rather than the indiscriminate destruction of the organelles. The COX turnover number (e- x s(-1) x cytochrome aa3(-1)) was greater for the enzyme from precommitment than postcommitment larvae, indicating a change in the enzyme structure and/or its lipid environment during the early stages of metamorphosis. The turnover number of COX in the intact mitochondria (in organello COX) was also lower in postcommitment larvae. In addition to changes in the protein or membrane phospholipids, the metamorphic decline in this rate constant may be a result of the observed loss of endogenous cytochrome c.

  15. Chlamydomonas outer arm dynein alters conformation in response to Ca2+.

    Science.gov (United States)

    Sakato, Miho; Sakakibara, Hitoshi; King, Stephen M

    2007-09-01

    We have previously shown that Ca(2+) directly activates ATP-sensitive microtubule binding by a Chlamydomonas outer arm dynein subparticle containing the beta and gamma heavy chains (HCs). The gamma HC-associated LC4 light chain is a member of the calmodulin family and binds 1-2 Ca(2+) with K(Ca) = 3 x 10(-5) M in vitro, suggesting it may act as a Ca(2+) sensor for outer arm dynein. Here we investigate interactions between the LC4 light chain and gamma HC. Two IQ consensus motifs for binding calmodulin-like proteins are located within the stem domain of the gamma heavy chain. In vitro experiments indicate that LC4 undergoes a Ca(2+)-dependent interaction with the IQ motif domain while remaining tethered to the HC. LC4 also moves into close proximity of the intermediate chain IC1 in the presence of Ca(2+). The sedimentation profile of the gamma HC subunit changed subtly upon Ca(2+) addition, suggesting that the entire complex had become more compact, and electron microscopy of the isolated gamma subunit revealed a distinct alteration in conformation of the N-terminal stem in response to Ca(2+) addition. We propose that Ca(2+)-dependent conformational change of LC4 has a direct effect on the stem domain of the gamma HC, which eventually leads to alterations in mechanochemical interactions between microtubules and the motor domain(s) of the outer dynein arm.

  16. High thermal conductivity connector having high electrical isolation

    Science.gov (United States)

    Nieman, Ralph C.; Gonczy, John D.; Nicol, Thomas H.

    1995-01-01

    A method and article for providing a low-thermal-resistance, high-electrical-isolation heat intercept connection. The connection method involves clamping, by thermal interference fit, an electrically isolating cylinder between an outer metallic ring and an inner metallic disk. The connection provides durable coupling of a heat sink and a heat source.

  17. Isolated galaxies

    International Nuclear Information System (INIS)

    Einasto, Maret

    1990-01-01

    To test for the possible presence of really isolated galaxies, which form a randomly distributed population in voids, we compare the distribution of most isolated galaxies in an observed sample with distributions of the same number of random points using the nearest neighbour test. The results show that the random population of really isolated galaxies does not exist - even the most isolated galaxies are connected with systems of galaxies, forming their outlying parts. (author)

  18. Interactions of copper and thermal stress on mitochondrial bioenergetics in rainbow trout, Oncorhynchus mykiss

    International Nuclear Information System (INIS)

    Sappal, Ravinder; MacDonald, Nicole; Fast, Mark; Stevens, Don; Kibenge, Fred; Siah, Ahmed; Kamunde, Collins

    2014-01-01

    Highlights: • Interacting effects of Cu and temperature were investigated in rainbow trout liver mitochondria. • Mitochondrial functional indices are highly sensitive to temperature change. • High and low temperatures sensitize mitochondria to adverse effects of Cu. • Cu induces a highly temperature-sensitive mitochondrial permeability transition pore. • Cu-imposed mitochondrial membrane potential dissipation is mediated by reactive oxygen species. - Abstract: Thermal stress may influence how organisms respond to concurrent or subsequent chemical, physical and biotic stressors. To unveil the potential mechanisms via which thermal stress modulates metals-induced bioenergetic disturbances, the interacting effects of temperature and copper (Cu) were investigated in vitro. Mitochondria isolated from rainbow trout livers were exposed to a range of Cu concentrations at three temperatures (5, 15 and 25 °C) with measurement of mitochondrial complex I (mtCI)-driven respiratory flux indices and uncoupler-stimulated respiration. Additional studies assessed effects of temperature and Cu on mtCI enzyme activity, induction of mitochondrial permeability transition pore (MPTP), swelling kinetics and mitochondrial membrane potential (MMP). Maximal and basal respiration rates, as well as the proton leak, increased with temperature with the Q 10 effects being higher at lower temperatures. The effect of Cu depended on the mitochondrial functional state in that the maximal respiration was monotonically inhibited by Cu exposure while low and high Cu concentrations stimulated and inhibited the basal respiration/proton leak, respectively. Importantly, temperature exacerbated the effects of Cu by lowering the concentration of the metal required for toxicity and causing loss of thermal dependence of mitochondrial respiration. Mitochondrial complex I activity was inhibited by Cu but was not affected by incubation temperature. Compared with the calcium (Ca) positive control, Cu

  19. Interactions of copper and thermal stress on mitochondrial bioenergetics in rainbow trout, Oncorhynchus mykiss

    Energy Technology Data Exchange (ETDEWEB)

    Sappal, Ravinder [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); MacDonald, Nicole [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); Fast, Mark [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); Stevens, Don [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); Kibenge, Fred [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada); Siah, Ahmed [British Columbia Centre for Aquatic Health Sciences, 871A Island Highway, Campbell River, BC V9W 2C2 (Canada); Kamunde, Collins, E-mail: ckamunde@upei.ca [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3 (Canada)

    2014-12-15

    Highlights: • Interacting effects of Cu and temperature were investigated in rainbow trout liver mitochondria. • Mitochondrial functional indices are highly sensitive to temperature change. • High and low temperatures sensitize mitochondria to adverse effects of Cu. • Cu induces a highly temperature-sensitive mitochondrial permeability transition pore. • Cu-imposed mitochondrial membrane potential dissipation is mediated by reactive oxygen species. - Abstract: Thermal stress may influence how organisms respond to concurrent or subsequent chemical, physical and biotic stressors. To unveil the potential mechanisms via which thermal stress modulates metals-induced bioenergetic disturbances, the interacting effects of temperature and copper (Cu) were investigated in vitro. Mitochondria isolated from rainbow trout livers were exposed to a range of Cu concentrations at three temperatures (5, 15 and 25 °C) with measurement of mitochondrial complex I (mtCI)-driven respiratory flux indices and uncoupler-stimulated respiration. Additional studies assessed effects of temperature and Cu on mtCI enzyme activity, induction of mitochondrial permeability transition pore (MPTP), swelling kinetics and mitochondrial membrane potential (MMP). Maximal and basal respiration rates, as well as the proton leak, increased with temperature with the Q{sub 10} effects being higher at lower temperatures. The effect of Cu depended on the mitochondrial functional state in that the maximal respiration was monotonically inhibited by Cu exposure while low and high Cu concentrations stimulated and inhibited the basal respiration/proton leak, respectively. Importantly, temperature exacerbated the effects of Cu by lowering the concentration of the metal required for toxicity and causing loss of thermal dependence of mitochondrial respiration. Mitochondrial complex I activity was inhibited by Cu but was not affected by incubation temperature. Compared with the calcium (Ca) positive control

  20. Comparative analysis of the mitochondrial genome of the fungus Colletotrichum lindemuthianum, the causal agent of anthracnose in common beans.

    Science.gov (United States)

    de Queiroz, Casley Borges; Santana, Mateus Ferreira; Pereira Vidigal, Pedro M; de Queiroz, Marisa Vieira

    2018-03-01

    Fungi of the genus Colletotrichum are economically important and are used as models in plant-pathogen interaction studies. In this study, the complete mitochondrial genomes of two Colletotrichum lindemuthianum isolates were sequenced and compared with the mitochondrial genomes of seven species of Colletotrichum. The mitochondrial genome of C. lindemuthianum is a typical circular molecule 37,446 bp (isolate 89 A 2 2-3) and 37,440 bp (isolate 83.501) in length. The difference of six nucleotides between the two genomes is the result of a deletion in the ribosomal protein S3 (rps3) gene in the 83.501 isolate. In addition, substitution of adenine for guanine within the rps3 gene in the mitochondrial genome of the 83.501 isolate was observed. Compared to the previously sequenced C. lindemuthianum mitochondrial genome, an exon no annotated in the cytochrome c oxidase I (cox1) gene and a non-conserved open reading frame (ncORF) were observed. The size of the mitochondrial genomes of the seven species of Colletotrichum was highly variable, being attributed mainly to the ncORF, ranging from one to 10 and also from introns ranging from one to 11 and which encode a total of up to nine homing endonucleases. This paper reports for the first time by means of transcriptome that then ncORFs are transcribed in Colletotrichum spp. Phylogeny data revealed that core mitochondrial genes could be used as an alternative in phylogenetic relationship studies in Colletotrichum spp. This work contributes to the genetic and biological knowledge of Colletotrichum spp., which is of great economic and scientific importance.

  1. Polypeptide Translocation Through the Mitochondrial TOM Channel: Temperature-Dependent Rates at the Single-Molecule Level.

    Science.gov (United States)

    Mahendran, Kozhinjampara R; Lamichhane, Usha; Romero-Ruiz, Mercedes; Nussberger, Stephan; Winterhalter, Mathias

    2013-01-03

    The TOM protein complex facilitates the transfer of nearly all mitochondrial preproteins across outer mitochondrial membranes. Here we characterized the effect of temperature on facilitated translocation of a mitochondrial presequence peptide pF1β. Ion current fluctuations analysis through single TOM channels revealed thermodynamic and kinetic parameters of substrate binding and allowed determining the energy profile of peptide translocation. The activation energy for the on-rate and off-rate of the presequence peptide into the TOM complex was symmetric with respect to the electric field and estimated to be about 15 and 22 kT per peptide. These values are above that expected for free diffusion of ions in water (6 kT) and reflect the stronger interaction in the channel. Both values are in the range for typical enzyme kinetics and suggest one process without involving large conformational changes within the channel protein.

  2. Ultrasonic examination of defects close to the outer surface

    International Nuclear Information System (INIS)

    Benoist, P.; Serre, M.; Champigny, F.

    1986-11-01

    During the examination of a pressurized water reactor vessel with an in Service Inspection Machine (MIS), various welds are scanned with immersion ultrasonic focused transducers from the inside of the vessel. Defects close to the outer surface are sometimes detected, and sizing with the successive 6 dB drop method leads to oversize some indications; this is caused by various reflections on the outer wall; the corner echo is of particular importance here. CEA and EDF have started an experimental program in order to study the response of volumetric and planar defects located near the outer surface. We present here the first results obtained with artificial defects. 2 refs

  3. Structural Aspects of Bacterial Outer Membrane Protein Assembly.

    Science.gov (United States)

    Calmettes, Charles; Judd, Andrew; Moraes, Trevor F

    2015-01-01

    The outer membrane of Gram-negative bacteria is predominantly populated by β-Barrel proteins and lipid anchored proteins that serve a variety of biological functions. The proper folding and assembly of these proteins is essential for bacterial viability and often plays a critical role in virulence and pathogenesis. The β-barrel assembly machinery (Bam) complex is responsible for the proper assembly of β-barrels into the outer membrane of Gram-negative bacteria, whereas the localization of lipoproteins (Lol) system is required for proper targeting of lipoproteins to the outer membrane.

  4. Genetic characteristics of mitochondrial DNA was associated with colorectal carcinogenesis and its prognosis.

    Directory of Open Access Journals (Sweden)

    Jae-Ho Lee

    Full Text Available Clinical value of mitochondrial DNA has been described in colorectal cancer (CRC. To clarify its role in colorectal carcinogenesis, mitochondrial microsatellite instability (mtMSI and other markers were investigated in CRCs and their precancerous lesions, as a multitier genetic study. DNA was isolated from paired normal and tumoral tissues in 78 tubular adenomas (TAs, 34 serrated polyps (SPs, and 100 CRCs. mtMSI, nucleus microsatellite instability (nMSI, KRAS mutation, and BRAF mutation were investigated in these tumors and their statistical analysis was performed. mtMSI was found in 30% of CRCs and 21.4% of precancerous lesions. Mitochondrial copy number was higher in SPs than TAs and it was associated with mtMSI in low grade TAs. KRAS and BRAF mutations were mutually exclusive in TAs and SPs. CRCs with mtMSI showed shorter overall survival times than the patients without mtMSI. In CRCs without nMSI or BRAF mutation, mtMSI was a more accurate marker for predicting prognosis. The genetic change of mitochondrial DNA is an early and independent event in colorectal precancerous lesions and mtMSI and mitochondrial contents are associated with the tubular adenoma-carcinoma sequence, resulting in poor prognosis. This result suggested that the genetic change in mitochondrial DNA appears to be a possible prognosis marker in CRC.

  5. Antioxidant effect of exercise: Exploring the role of the mitochondrial complex I superassembly

    Directory of Open Access Journals (Sweden)

    J.R. Huertas

    2017-10-01

    Full Text Available Mitochondrial respiratory complexes become assembled into supercomplexes (SC under physiological conditions. One of the functional roles of these entities is the limitation of reactive oxygen species (ROS produced by complex I (CI of the respiratory chain. We sought to determine whether the systemic antioxidant effect of exercise is mediated by the assembly of mitochondrial CIs into SCs in rats. Male Wistar rats were exercise trained or remained sedentary for ten weeks; then, blood samples were collected, and the gastrocnemius muscle was isolated. The assembly of mitochondrial SCs and the lipid peroxidation of the mitochondrial and plasmatic fractions were assessed. Our results demonstrate that exercise induced the assembly of CI into SCs in the gastrocnemius and induced a systemic decrease in lipid peroxidation. We also found an inverse association between the superassembly of CIs and mitochondrial lipid peroxidation (p < 0.01 and protein carbonyls (p < 0.05. We conclude that exercise induces the chronic assembly of CIs into SCs, which provide mitochondrial protection against oxidative damage, at least in the studied muscle. Given the relevant role that mitochondria play in health and disease, these findings should help to elucidate the role of exercise as a therapeutic approach for metabolic diseases.

  6. Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation.

    Science.gov (United States)

    Agrimi, Gennaro; Mena, Maria C; Izumi, Kazuki; Pisano, Isabella; Germinario, Lucrezia; Fukuzaki, Hisashi; Palmieri, Luigi; Blank, Lars M; Kitagaki, Hiroshi

    2014-03-01

    Although the decrease in pyruvate secretion by brewer's yeasts during fermentation has long been desired in the alcohol beverage industry, rather little is known about the regulation of pyruvate accumulation. In former studies, we developed a pyruvate under-secreting sake yeast by isolating a strain (TCR7) tolerant to ethyl α-transcyanocinnamate, an inhibitor of pyruvate transport into mitochondria. To obtain insights into pyruvate metabolism, in this study, we investigated the mitochondrial activity of TCR7 by oxigraphy and (13) C-metabolic flux analysis during aerobic growth. While mitochondrial pyruvate oxidation was higher, glycerol production was decreased in TCR7 compared with the reference. These results indicate that mitochondrial activity is elevated in the TCR7 strain with the consequence of decreased pyruvate accumulation. Surprisingly, mitochondrial activity is much higher in the sake yeast compared with CEN.PK 113-7D, the reference strain in metabolic engineering. When shifted from aerobic to anaerobic conditions, sake yeast retains a branched mitochondrial structure for a longer time than laboratory strains. The regulation of mitochondrial activity can become a completely novel approach to manipulate the metabolic profile during fermentation of brewer's yeasts. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  7. A Role for Mitochondrial Phosphoenolpyruvate Carboxykinase (PEPCK-M) in the Regulation of Hepatic Gluconeogenesis*

    Science.gov (United States)

    Stark, Romana; Guebre-Egziabher, Fitsum; Zhao, Xiaojian; Feriod, Colleen; Dong, Jianying; Alves, Tiago C.; Ioja, Simona; Pongratz, Rebecca L.; Bhanot, Sanjay; Roden, Michael; Cline, Gary W.; Shulman, Gerald I.; Kibbey, Richard G.

    2014-01-01

    Synthesis of phosphoenolpyruvate (PEP) from oxaloacetate is an absolute requirement for gluconeogenesis from mitochondrial substrates. Generally, this reaction has solely been attributed to the cytosolic isoform of PEPCK (PEPCK-C), although loss of the mitochondrial isoform (PEPCK-M) has never been assessed. Despite catalyzing the same reaction, to date the only significant role reported in mammals for the mitochondrial isoform is as a glucose sensor necessary for insulin secretion. We hypothesized that this nutrient-sensing mitochondrial GTP-dependent pathway contributes importantly to gluconeogenesis. PEPCK-M was acutely silenced in gluconeogenic tissues of rats using antisense oligonucleotides both in vivo and in isolated hepatocytes. Silencing PEPCK-M lowers plasma glucose, insulin, and triglycerides, reduces white adipose, and depletes hepatic glycogen, but raises lactate. There is a switch of gluconeogenic substrate preference to glycerol that quantitatively accounts for a third of glucose production. In contrast to the severe mitochondrial deficiency characteristic of PEPCK-C knock-out livers, hepatocytes from PEPCK-M-deficient livers maintained normal oxidative function. Consistent with its predicted role, gluconeogenesis rates from hepatocytes lacking PEPCK-M are severely reduced for lactate, alanine, and glutamine, but not for pyruvate and glycerol. Thus, PEPCK-M has a direct role in fasted and fed glucose homeostasis, and this mitochondrial GTP-dependent pathway should be reconsidered for its involvement in both normal and diabetic metabolism. PMID:24497630

  8. A role for mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) in the regulation of hepatic gluconeogenesis.

    Science.gov (United States)

    Stark, Romana; Guebre-Egziabher, Fitsum; Zhao, Xiaojian; Feriod, Colleen; Dong, Jianying; Alves, Tiago C; Ioja, Simona; Pongratz, Rebecca L; Bhanot, Sanjay; Roden, Michael; Cline, Gary W; Shulman, Gerald I; Kibbey, Richard G

    2014-03-14

    Synthesis of phosphoenolpyruvate (PEP) from oxaloacetate is an absolute requirement for gluconeogenesis from mitochondrial substrates. Generally, this reaction has solely been attributed to the cytosolic isoform of PEPCK (PEPCK-C), although loss of the mitochondrial isoform (PEPCK-M) has never been assessed. Despite catalyzing the same reaction, to date the only significant role reported in mammals for the mitochondrial isoform is as a glucose sensor necessary for insulin secretion. We hypothesized that this nutrient-sensing mitochondrial GTP-dependent pathway contributes importantly to gluconeogenesis. PEPCK-M was acutely silenced in gluconeogenic tissues of rats using antisense oligonucleotides both in vivo and in isolated hepatocytes. Silencing PEPCK-M lowers plasma glucose, insulin, and triglycerides, reduces white adipose, and depletes hepatic glycogen, but raises lactate. There is a switch of gluconeogenic substrate preference to glycerol that quantitatively accounts for a third of glucose production. In contrast to the severe mitochondrial deficiency characteristic of PEPCK-C knock-out livers, hepatocytes from PEPCK-M-deficient livers maintained normal oxidative function. Consistent with its predicted role, gluconeogenesis rates from hepatocytes lacking PEPCK-M are severely reduced for lactate, alanine, and glutamine, but not for pyruvate and glycerol. Thus, PEPCK-M has a direct role in fasted and fed glucose homeostasis, and this mitochondrial GTP-dependent pathway should be reconsidered for its involvement in both normal and diabetic metabolism.

  9. On the Existence of Regular and Irregular Outer Moons Orbiting the Pluto–Charon System

    Energy Technology Data Exchange (ETDEWEB)

    Michaely, Erez; Perets, Hagai B.; Grishin, Evgeni [Physics Department, Technion—Israel Institute of Technology, Haifa 3200004 (Israel)

    2017-02-10

    The dwarf planet Pluto is known to host an extended system of five co-planar satellites. Previous studies have explored the formation and evolution of the system in isolation, neglecting perturbative effects by the Sun. Here we show that secular evolution due to the Sun can strongly affect the evolution of outer satellites and rings in the system, if such exist. Although precession due to extended gravitational potential from the inner Pluto–Charon binary quench such secular evolution up to a {sub crit} ∼ 0.0035 au (∼0.09 R {sub Hill} the Hill radius; including all of the currently known satellites), outer orbits can be significantly altered. In particular, we find that co-planar rings and satellites should not exist beyond a {sub crit}; rather, satellites and dust particles in these regions secularly evolve on timescales ranging between 10{sup 4} and 10{sup 6} years, and quasi-periodically change their inclinations and eccentricities through secular evolution (Lidov–Kozai oscillations). Such oscillations can lead to high inclinations and eccentricities, constraining the range where such satellites (and dust particles) can exist without crossing the orbits of the inner satellites or crossing the outer Hill stability range. Outer satellites, if such exist are therefore likely to be irregular satellites, with orbits limited to be non-circular and/or highly inclined. Current observations, including the recent data from the New-Horizons mission explored only inner regions (<0.0012 au) and excluded the existence of additional satellites; however, the irregular satellites discussed here should reside farther, in the yet uncharted regions around Pluto.

  10. On the Existence of Regular and Irregular Outer Moons Orbiting the Pluto–Charon System

    International Nuclear Information System (INIS)

    Michaely, Erez; Perets, Hagai B.; Grishin, Evgeni

    2017-01-01

    The dwarf planet Pluto is known to host an extended system of five co-planar satellites. Previous studies have explored the formation and evolution of the system in isolation, neglecting perturbative effects by the Sun. Here we show that secular evolution due to the Sun can strongly affect the evolution of outer satellites and rings in the system, if such exist. Although precession due to extended gravitational potential from the inner Pluto–Charon binary quench such secular evolution up to a crit ∼ 0.0035 au (∼0.09 R Hill the Hill radius; including all of the currently known satellites), outer orbits can be significantly altered. In particular, we find that co-planar rings and satellites should not exist beyond a crit ; rather, satellites and dust particles in these regions secularly evolve on timescales ranging between 10 4 and 10 6 years, and quasi-periodically change their inclinations and eccentricities through secular evolution (Lidov–Kozai oscillations). Such oscillations can lead to high inclinations and eccentricities, constraining the range where such satellites (and dust particles) can exist without crossing the orbits of the inner satellites or crossing the outer Hill stability range. Outer satellites, if such exist are therefore likely to be irregular satellites, with orbits limited to be non-circular and/or highly inclined. Current observations, including the recent data from the New-Horizons mission explored only inner regions (<0.0012 au) and excluded the existence of additional satellites; however, the irregular satellites discussed here should reside farther, in the yet uncharted regions around Pluto.

  11. Autophagy capacity and sub-mitochondrial heterogeneity shape Bnip3-induced mitophagy regulation of apoptosis.

    Science.gov (United States)

    Choe, Sehyo Charley; Hamacher-Brady, Anne; Brady, Nathan Ryan

    2015-08-08

    Mitochondria are key regulators of apoptosis. In response to stress, BH3-only proteins activate pro-apoptotic Bcl2 family proteins Bax and Bak, which induce mitochondrial outer membrane permeabilization (MOMP). While the large-scale mitochondrial release of pro-apoptotic proteins activates caspase-dependent cell death, a limited release results in sub-lethal caspase activation which promotes tumorigenesis. Mitochondrial autophagy (mitophagy) targets dysfunctional mitochondria for degradation by lysosomes, and undergoes extensive crosstalk with apoptosis signaling, but its influence on apoptosis remains undetermined. The BH3-only protein Bnip3 integrates apoptosis and mitophagy signaling at different signaling domains. Bnip3 inhibits pro-survival Bcl2 members via its BH3 domain and activates mitophagy through its LC3 Interacting Region (LIR), which is responsible for binding to autophagosomes. Previously, we have shown that Bnip3-activated mitophagy prior to apoptosis induction can reduce mitochondrial activation of caspases, suggesting that a reduction to mitochondrial levels may be pro-survival. An outstanding question is whether organelle dynamics and/or recently discovered subcellular variations of protein levels responsible for both MOMP sensitivity and crosstalk between apoptosis and mitophagy can influence the cellular apoptosis decision event. To that end, here we undertook a systems biology analysis of mitophagy-apoptosis crosstalk at the level of cellular mitochondrial populations. Based on experimental findings, we developed a multi-scale, hybrid model with an individually adaptive mitochondrial population, whose actions are determined by protein levels, embedded in an agent-based model (ABM) for simulating subcellular dynamics and local feedback via reactive oxygen species signaling. Our model, supported by experimental evidence, identified an emergent regulatory structure within canonical apoptosis signaling. We show that the extent of mitophagy is

  12. Atmospheric Mining in the Outer Solar System: Outer Planet Orbital Transfer and Lander Analyses

    Science.gov (United States)

    Palaszewski, Bryan

    2016-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and deuterium can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and deuterium were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. Analyses of orbital transfer vehicles (OTVs), landers, and the issues with in-situ resource utilization (ISRU) mining factories are included. Preliminary observations are presented on near-optimal selections of moon base orbital locations, OTV power levels, and OTV and lander rendezvous points. For analyses of round trip OTV flights from Uranus to Miranda or Titania, a 10- Megawatt electric (MWe) OTV power level and a 200 metricton (MT) lander payload were selected based on a relative short OTV trip time and minimization of the number of lander flights. A similar optimum power level is suggested for OTVs flying from low orbit around Neptune to Thalassa or Triton. Several moon base sites at Uranus and Neptune and the OTV requirements to support them are also addressed.

  13. Mitochondrial disorders in congenital myopathies

    Directory of Open Access Journals (Sweden)

    D. A. Kharlamov

    2014-01-01

    Full Text Available The literature review gives data on the role of mitochondrial disorders in the pathogenesis of congenital myopathies: congenital muscular dystrophies and congenital structural myopathies. It describes changes in congenital muscular dystrophies with type VI collagen, in myodystrophy with giant mitochondria, in congenital central core myopathies, myotubular myopathy, etc. Clinical and experimental findings are presented. Approaches to therapy for energy disorders in congenital myopathies are depicted.

  14. UCP2 muscle gene transfer modifies mitochondrial membrane potential.

    Science.gov (United States)

    Marti, A; Larrarte, E; Novo, F J; Garcia, M; Martinez, J A

    2001-01-01

    The aim of this work was to evaluate the effect of uncoupling protein 2 (UCP2) muscle gene transfer on mitochondrial activity. Five week-old male Wistar rats received an intramuscular injection of plasmid pXU1 containing UCP2 cDNA in the right tibialis anterior muscles. Left tibialis anterior muscles were injected with vehicle as control. Ten days after DNA injection, tibialis anterior muscles were dissected and muscle mitochondria isolated and analyzed. There were two mitochondrial populations in the muscle after UCP2 gene transfer, one of low fluorescence and complexity and the other, showing high fluorescence and complexity. UCP2 gene transfer resulted in a 3.6 fold increase in muscle UCP2 protein levels compared to control muscles assessed by Western blotting. Furthermore, a significant reduction in mitochondria membrane potential assessed by spectrofluorometry and flow cytometry was observed. The mitochondria membrane potential reduction might account for a decrease in fluorescence of the low fluorescence mitochondrial subpopulation. It has been demonstrated that UCP2 muscle gene transfer in vivo is associated with a lower mitochondria membrane potential. Our results suggest the potential involvement of UCP2 in uncoupling respiration. International Journal of Obesity (2001) 25, 68-74

  15. Tributyltin (TBT) and mitochondrial respiration in mussel digestive gland.

    Science.gov (United States)

    Nesci, Salvatore; Ventrella, Vittoria; Trombetti, Fabiana; Pirini, Maurizio; Pagliarani, Alessandra

    2011-06-01

    The toxicity of organotins and especially tri-n-butyltin (TBT) on mitochondria is well known. However as far as we are aware, effects on mitochondrial respiration are unexplored in mollusks. In this work mitochondria isolated from the digestive gland of Mytilus galloprovincialis and susceptive to the classical respiratory chain inhibitors, were assayed in the presence of micromolar TBT concentrations to investigate mitochondrial respiratory activities. Intact and freeze-thawed mitochondria were used. TBT significantly inhibited oxygen consumption in the presence of glutamate/malate or succinate as substrates. Conversely cytochrome c oxidase activity (complex IV), assayed both polarographically and spectrophotometrically, was unaffected. The addition of 1,4-dithioerythritol (DTE) decreased the TBT-driven inhibition of complexes I and III. The TBT capability of covalent binding to thiol groups of mitochondrial proteins in a dose-dependent manner was confirmed by the aid of Ellman's reagent. Data strongly suggests that TBT may prevent the electron transfer from complexes I and III to downhill respiratory chain complexes by binding to critical SH residues. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Induced pluripotent stem cells with a pathological mitochondrial DNA deletion

    Science.gov (United States)

    Cherry, Anne B. C.; Gagne, Katelyn E.; McLoughlin, Erin M.; Baccei, Anna; Gorman, Bryan; Hartung, Odelya; Miller, Justine D.; Zhang, Jin; Zon, Rebecca L.; Ince, Tan A.; Neufeld, Ellis J.; Lerou, Paul H.; Fleming, Mark D.; Daley, George Q.; Agarwal, Suneet

    2013-01-01

    In congenital mitochondrial DNA (mtDNA) disorders, a mixture of normal and mutated mtDNA (termed heteroplasmy) exists at varying levels in different tissues, which determines the severity and phenotypic expression of disease. Pearson marrow pancreas syndrome (PS) is a congenital bone marrow failure disorder caused by heteroplasmic deletions in mtDNA. The cause of the hematopoietic failure in PS is unknown, and adequate cellular and animal models are lacking. Induced pluripotent stem (iPS) cells are particularly amenable for studying mtDNA disorders, as cytoplasmic genetic material is retained during direct reprogramming. Here we derive and characterize iPS cells from a patient with PS. Taking advantage of the tendency for heteroplasmy to change with cell passage, we isolated isogenic PS-iPS cells without detectable levels of deleted mtDNA. We found that PS-iPS cells carrying a high burden of deleted mtDNA displayed differences in growth, mitochondrial function, and hematopoietic phenotype when differentiated in vitro, compared to isogenic iPS cells without deleted mtDNA. Our results demonstrate that reprogramming somatic cells from patients with mtDNA disorders can yield pluripotent stem cells with varying burdens of heteroplasmy that might be useful in the study and treatment of mitochondrial diseases. PMID:23400930

  17. Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.

    Science.gov (United States)

    Weitzel, Erik K; Tasker, Ron; Brownell, William E

    2003-09-01

    Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell's lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations.

  18. Inner and Outer Recursive Neural Networks for Chemoinformatics Applications.

    Science.gov (United States)

    Urban, Gregor; Subrahmanya, Niranjan; Baldi, Pierre

    2018-02-26

    Deep learning methods applied to problems in chemoinformatics often require the use of recursive neural networks to handle data with graphical structure and variable size. We present a useful classification of recursive neural network approaches into two classes, the inner and outer approach. The inner approach uses recursion inside the underlying graph, to essentially "crawl" the edges of the graph, while the outer approach uses recursion outside the underlying graph, to aggregate information over progressively longer distances in an orthogonal direction. We illustrate the inner and outer approaches on several examples. More importantly, we provide open-source implementations [available at www.github.com/Chemoinformatics/InnerOuterRNN and cdb.ics.uci.edu ] for both approaches in Tensorflow which can be used in combination with training data to produce efficient models for predicting the physical, chemical, and biological properties of small molecules.

  19. Photoreceptor atrophy in acute zonal occult outer retinopathy

    DEFF Research Database (Denmark)

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.

    2006-01-01

    Purpose: To assess retinal morphology in acute zonal occult outer retinopathy (AZOOR). Methods: Three patients with a normal ophthalmoscopic fundus appearance, a history of photopsia, and visual field loss compatible with AZOOR were examined using optical coherence tomography, automated perimetry...

  20. Biguanides sensitize leukemia cells to ABT-737-induced apoptosis by inhibiting mitochondrial electron transport

    Science.gov (United States)

    Velez, Juliana; Pan, Rongqing; Lee, Jason T.C.; Enciso, Leonardo; Suarez, Marta; Duque, Jorge Eduardo; Jaramillo, Daniel; Lopez, Catalina; Morales, Ludis; Bornmann, William; Konopleva, Marina; Krystal, Gerald; Andreeff, Michael; Samudio, Ismael

    2016-01-01

    Metformin displays antileukemic effects partly due to activation of AMPK and subsequent inhibition of mTOR signaling. Nevertheless, Metformin also inhibits mitochondrial electron transport at complex I in an AMPK-independent manner, Here we report that Metformin and rotenone inhibit mitochondrial electron transport and increase triglyceride levels in leukemia cell lines, suggesting impairment of fatty acid oxidation (FAO). We also report that, like other FAO inhibitors, both agents and the related biguanide, Phenformin, increase sensitivity to apoptosis induction by the bcl-2 inhibitor ABT-737 supporting the notion that electron transport antagonizes activation of the intrinsic apoptosis pathway in leukemia cells. Both biguanides and rotenone induce superoxide generation in leukemia cells, indicating that oxidative damage may sensitize toABT-737 induced apoptosis. In addition, we demonstrate that Metformin sensitizes leukemia cells to the oligomerization of Bak, suggesting that the observed synergy with ABT-737 is mediated, at least in part, by enhanced outer mitochondrial membrane permeabilization. Notably, Phenformin was at least 10-fold more potent than Metformin in abrogating electron transport and increasing sensitivity to ABT-737, suggesting that this agent may be better suited for targeting hematological malignancies. Taken together, our results suggest that inhibition of mitochondrial metabolism by Metformin or Phenformin is associated with increased leukemia cell susceptibility to induction of intrinsic apoptosis, and provide a rationale for clinical studies exploring the efficacy of combining biguanides with the orally bioavailable derivative of ABT-737, Venetoclax. PMID:27283492

  1. Orphan nuclear receptor TR3 acts in autophagic cell death via mitochondrial signaling pathway.

    Science.gov (United States)

    Wang, Wei-jia; Wang, Yuan; Chen, Hang-zi; Xing, Yong-zhen; Li, Feng-wei; Zhang, Qian; Zhou, Bo; Zhang, Hong-kui; Zhang, Jie; Bian, Xue-li; Li, Li; Liu, Yuan; Zhao, Bi-xing; Chen, Yan; Wu, Rong; Li, An-zhong; Yao, Lu-ming; Chen, Ping; Zhang, Yi; Tian, Xu-yang; Beermann, Friedrich; Wu, Mian; Han, Jiahuai; Huang, Pei-qiang; Lin, Tianwei; Wu, Qiao

    2014-02-01

    Autophagy is linked to cell death, yet the associated mechanisms are largely undercharacterized. We discovered that melanoma, which is generally resistant to drug-induced apoptosis, can undergo autophagic cell death with the participation of orphan nuclear receptor TR3. A sequence of molecular events leading to cellular demise is launched by a specific chemical compound, 1-(3,4,5-trihydroxyphenyl)nonan-1-one, newly acquired from screening a library of TR3-targeting compounds. The autophagic cascade comprises TR3 translocation to mitochondria through interaction with the mitochondrial outer membrane protein Nix, crossing into the mitochondrial inner membrane through Tom40 and Tom70 channel proteins, dissipation of mitochondrial membrane potential by the permeability transition pore complex ANT1-VDAC1 and induction of autophagy. This process leads to excessive mitochondria clearance and irreversible cell death. It implicates a new approach to melanoma therapy through activation of a mitochondrial signaling pathway that integrates a nuclear receptor with autophagy for cell death.

  2. Mitochondrial Drugs for Alzheimer Disease

    Directory of Open Access Journals (Sweden)

    Xiongwei Zhu

    2009-12-01

    Full Text Available Therapeutic strategies for Alzheimer disease (AD have yet to offer a diseasemodifying effect to stop the debilitating progression of neurodegeneration and cognitive decline. Rather, treatments thus far are limited to agents that slow disease progression without halting it, and although much work towards a cure is underway, a greater understanding of disease etiology is certainly necessary for any such achievement. Mitochondria, as the centers of cellular metabolic activity and the primary generators of reactive oxidative species in the cell, received particular attention especially given that mitochondrial defects are known to contribute to cellular damage. Furthermore, as oxidative stress has come to the forefront of AD as a causal theory, and as mitochondrial damage is known to precede much of the hallmark pathologies of AD, it seems increasingly apparent that this metabolic organelle is ultimately responsible for much, if not all of disease pathogenesis. In this review, we review the role of neuronal mitochondria in the pathogenesis of AD and critically assess treatment strategies that utilize this upstream access point as a method for disease prevention. We suspect that, with a revived focus on mitochondrial repair and protection, an effective and realistic therapeutic agent can be successfully developed.

  3. Stimulated human mast cells secrete mitochondrial components that have autocrine and paracrine inflammatory actions.

    Directory of Open Access Journals (Sweden)

    Bodi Zhang

    Full Text Available Mast cells are hematopoietically-derived tissue immune cells that participate in acquired and innate immunity, as well as in inflammation through release of many chemokines and cytokines, especially in response to the pro-inflammatory peptide substance P (SP. Inflammation is critical in the pathogenesis of many diseases, but the trigger(s is often unknown. We investigated if mast cell stimulation leads to secretion of mitochondrial components and whether these could elicit autocrine and/or paracrine inflammatory effects. Here we show that human LAD2 mast cells stimulated by IgE/anti-IgE or by the SP led to secretion of mitochondrial particles, mitochondrial (mt mtDNA and ATP without cell death. Mitochondria purified from LAD2 cells and, when mitochondria added to mast cells trigger degranulation and release of histamine, PGD(2, IL-8, TNF, and IL-1β. This stimulatory effect is partially inhibited by an ATP receptor antagonist and by DNAse. These results suggest that the mitochondrial protein fraction may also contribute. Purified mitochondria also stimulate IL-8 and vascular endothelial growth factor (VEGF release from cultured human keratinocytes, and VEGF release from primary human microvascular endothelial cells. In order to investigate if mitochondrial components could be secreted in vivo, we injected rats intraperiotoneally (ip with compound 48/80, which mimicks the action of SP. Peritoneal mast cells degranulated and mitochondrial particles were documented by transimission electron microscopy outside the cells. We also wished to investigate if mitochondrial components secreted locally could reach the systemic circulation. Administration ip of mtDNA isolated from LAD2 cells in rats was detected in their serum within 4 hr, indicating that extravascular mtDNA could enter the systemic circulation. Secretion of mitochondrial components from stimulated live mast cells may act as "autopathogens" contributing to the pathogenesis of inflammatory

  4. Proposal for the LHCb outer tracker front-end electronics

    CERN Document Server

    Deppe, H; Feuerstack-Raible, M; Srowig, A; Stange, U; Hommels, B; Sluijk, T

    2001-01-01

    A market survey on available TDCs for reading out the LHCb Outer Tracker has left over only one TDC, which is not optimal for this purpose. Hence, a new readout architecture which is based on a TDC to be developed anew has been defined. This system fits optimal the requirements of the LHCb Outer Tracker and also should be much cheaper. The system and its main issues are described in this paper.

  5. Developments for the outer tracking system of the LHCb experiment

    CERN Document Server

    Bachmann, S; Haas, T; Uwer, U; Walter, M; Wiedner, D

    2004-01-01

    The outer tracking system of the LHCb experiment is discussed. The outer tracking system (OT) is made of three stations and every station is made up of four detecting planes with a double layer of straw tubes. The straw tubes are mounted in detector module boxes made up of sandwich panels. The use of a counting gas with a high drift velocity is suggested to cope with high bunch crossing rate at the LHCb experiment. (Edited abstract) 3 Refs.

  6. Inner and outer cylinders of the CMS vacuum tank.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the already installed outer cylinder, through which this photo was taken.

  7. Star laws: legal controls on armed conflict in outer space

    International Nuclear Information System (INIS)

    Stephens, Dale

    2016-01-01

    An undeclared military space race is unfolding yet there is no clear understanding of how international las operates in the field of armed conflict in outer space. In conjunction with McGill University Law School, Montreal, Canada, a 'Manual on international law applicable to military uses of outer space' has been drafted. This article looks at types of space weapons, previous space treaties and discusses humanitarian law.

  8. Fisetin Confers Cardioprotection against Myocardial Ischemia Reperfusion Injury by Suppressing Mitochondrial Oxidative Stress and Mitochondrial Dysfunction and Inhibiting Glycogen Synthase Kinase 3β Activity

    Directory of Open Access Journals (Sweden)

    Karthi Shanmugam

    2018-01-01

    Full Text Available Acute myocardial infarction (AMI is the leading cause of morbidity and mortality worldwide. Timely reperfusion is considered an optimal treatment for AMI. Paradoxically, the procedure of reperfusion can itself cause myocardial tissue injury. Therefore, a strategy to minimize the reperfusion-induced myocardial tissue injury is vital for salvaging the healthy myocardium. Herein, we investigated the cardioprotective effects of fisetin, a natural flavonoid, against ischemia/reperfusion (I/R injury (IRI using a Langendorff isolated heart perfusion system. I/R produced significant myocardial tissue injury, which was characterized by elevated levels of lactate dehydrogenase and creatine kinase in the perfusate and decreased indices of hemodynamic parameters. Furthermore, I/R resulted in elevated oxidative stress, uncoupling of the mitochondrial electron transport chain, increased mitochondrial swelling, a decrease of the mitochondrial membrane potential, and induction of apoptosis. Moreover, IRI was associated with a loss of the mitochondrial structure and decreased mitochondrial biogenesis. However, when the animals were pretreated with fisetin, it significantly attenuated the I/R-induced myocardial tissue injury, blunted the oxidative stress, and restored the structure and function of mitochondria. Mechanistically, the fisetin effects were found to be mediated via inhibition of glycogen synthase kinase 3β (GSK3β, which was confirmed by a biochemical assay and molecular docking studies.

  9. Fisetin Confers Cardioprotection against Myocardial Ischemia Reperfusion Injury by Suppressing Mitochondrial Oxidative Stress and Mitochondrial Dysfunction and Inhibiting Glycogen Synthase Kinase 3β Activity.

    Science.gov (United States)

    Shanmugam, Karthi; Ravindran, Sriram; Kurian, Gino A; Rajesh, Mohanraj

    2018-01-01

    Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality worldwide. Timely reperfusion is considered an optimal treatment for AMI. Paradoxically, the procedure of reperfusion can itself cause myocardial tissue injury. Therefore, a strategy to minimize the reperfusion-induced myocardial tissue injury is vital for salvaging the healthy myocardium. Herein, we investigated the cardioprotective effects of fisetin, a natural flavonoid, against ischemia/reperfusion (I/R) injury (IRI) using a Langendorff isolated heart perfusion system. I/R produced significant myocardial tissue injury, which was characterized by elevated levels of lactate dehydrogenase and creatine kinase in the perfusate and decreased indices of hemodynamic parameters. Furthermore, I/R resulted in elevated oxidative stress, uncoupling of the mitochondrial electron transport chain, increased mitochondrial swelling, a decrease of the mitochondrial membrane potential, and induction of apoptosis. Moreover, IRI was associated with a loss of the mitochondrial structure and decreased mitochondrial biogenesis. However, when the animals were pretreated with fisetin, it significantly attenuated the I/R-induced myocardial tissue injury, blunted the oxidative stress, and restored the structure and function of mitochondria. Mechanistically, the fisetin effects were found to be mediated via inhibition of glycogen synthase kinase 3 β (GSK3 β ), which was confirmed by a biochemical assay and molecular docking studies.

  10. Presence of a mitochondrial-type 70-kDa heat shock protein in Trichomonas vaginalis suggests a very early mitochondrial endosymbiosis in eukaryotes

    Science.gov (United States)

    Germot, Agnès; Philippe, Hervé; Le Guyader, Hervé

    1996-01-01

    Molecular phylogenetic analyses, based mainly on ribosomal RNA, show that three amitochondriate protist lineages, diplomonads, microsporidia, and trichomonads, emerge consistently at the base of the eukaryotic tree before groups having mitochondria. This suggests that these groups could have diverged before the mitochondrial endosymbiosis. Nevertheless, since all these organisms live in anaerobic environments, the absence of mitochondria might be due to secondary loss, as demonstrated for the later emerging eukaryote Entamoeba histolytica. We have now isolated from Trichomonas vaginalis a gene encoding a chaperone protein (HSP70) that in other lineages is addressed to the mitochondrial compartment. The phylogenetic reconstruction unambiguously located this HSP70 within a large set of mitochondrial sequences, itself a sister-group of α-purple bacteria. In addition, the T. vaginalis protein exhibits the GDAWV sequence signature, so far exclusively found in mitochondrial HSP70 and in proteobacterial dnaK. Thus mitochondrial endosymbiosis could have occurred earlier than previously assumed. The trichomonad double membrane-bounded organelles, the hydrogenosomes, could have evolved from mitochondria. PMID:8962101

  11. Presence of a mitochondrial-type 70-kDa heat shock protein in Trichomonas vaginalis suggests a very early mitochondrial endosymbiosis in eukaryotes.

    Science.gov (United States)

    Germot, A; Philippe, H; Le Guyader, H

    1996-12-10

    Molecular phylogenetic analyses, based mainly on ribosomal RNA, show that three amitochondriate protist lineages, diplomonads, microsporidia, and trichomonads, emerge consistently at the base of the eukaryotic tree before groups having mitochondria. This suggests that these groups could have diverged before the mitochondrial endosymbiosis. Nevertheless, since all these organisms live in anaerobic environments, the absence of mitochondria might be due to secondary loss, as demonstrated for the later emerging eukaryote Entamoeba histolytica. We have now isolated from Trichomonas vaginalis a gene encoding a chaperone protein (HSP70) that in other lineages is addressed to the mitochondrial compartment. The phylogenetic reconstruction unambiguously located this HSP70 within a large set of mitochondrial sequences, itself a sister-group of alpha-purple bacteria. In addition, the T. vaginalis protein exhibits the GDAWV sequence signature, so far exclusively found in mitochondrial HSP70 and in proteobacterial dnaK. Thus mitochondrial endosymbiosis could have occurred earlier than previously assumed. The trichomonad double membrane-bounded organelles, the hydrogenosomes, could have evolved from mitochondria.

  12. Targeted Transgenic Overexpression of Mitochondrial Thymidine Kinase (TK2) Alters Mitochondrial DNA (mtDNA) and Mitochondrial Polypeptide Abundance

    Science.gov (United States)

    Hosseini, Seyed H.; Kohler, James J.; Haase, Chad P.; Tioleco, Nina; Stuart, Tami; Keebaugh, Erin; Ludaway, Tomika; Russ, Rodney; Green, Elgin; Long, Robert; Wang, Liya; Eriksson, Staffan; Lewis, William

    2007-01-01

    Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-γ. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK1) were used to study NRTI mitochondrial toxicity. Echocardiography and nuclear magnetic resonance imaging defined cardiac performance and structure. TK gene copy and enzyme activity, mitochondrial (mt) DNA and polypeptide abundance, succinate dehydrogenase and cytochrome oxidase histochemistry, and electron microscopy correlated with transgenesis, mitochondrial structure, and biogenesis. Antiretroviral combinations simulated therapy. Untreated hTK1 or TK2 TGs exhibited normal left ventricle mass. In TK2 TGs, cardiac TK2 gene copy doubled, activity increased 300-fold, and mtDNA abundance doubled. Abundance of the 17-kd subunit of complex I, succinate dehydrogenase histochemical activity, and cristae density increased. NRTIs increased left ventricle mass 20% in TK2 TGs. TK activity increased 3 logs in hTK1 TGs, but no cardiac phenotype resulted. NRTIs abrogated functional effects of transgenically increased TK2 activity but had no effect on TK2 mtDNA abundance. Thus, NRTI mitochondrial phosphorylation by TK2 is integral to clinical NRTI mitochondrial toxicity. PMID:17322372

  13. THE OUTER MEMBRANE OF PATHOGENIC REPRESENTATIVES OF THE LEPTOSPIRA GENIUS

    Directory of Open Access Journals (Sweden)

    A. N. Vaganova

    2011-01-01

    Full Text Available Abstract. Pathogenic leptospires can infect wide spectrum of hosts and they can survive in the environment long time. The outer membrane is the cellular component participated in interaction of microorganisms and environment. In present time several proteins located in the outer membrane of leptospires which are responsible for colonization of host organism, protection from influence of immune system of host, transport of substances in to the cell and other processes have been described. The outer membrane contains proteins and lipopolysaccharide molecules which have citotoxic effect. It was shown that regulation of protein composition of membranes depends on several factors of environment such as temperature, osmolarity, presence of certain substances in environment. Lipopolysaccharide and protein molecules of outer membranes have antigenic properties. These molecules can be used in practice as the components of vaccine against leptospiroses and diagnostic tools. Current review summarize information concerning structural organization of the outer membrane of leptospires, diversities of incoming parts of molecules and regulation of their synthesis. Moreover, perspectives of practical using of the outer membrane components in diagnostics and prevention of leptospiroses are presented.

  14. Return of the mitochondrial DNA : Case study of mitochondrial genome evolution in the genus Fusarium

    NARCIS (Netherlands)

    Brankovics, Balázs

    2018-01-01

    Mitochondrial DNA played a prominent role in the fields of population genetics, systematics and evolutionary biology, due to its favorable characteristics, such as, uniparental inheritance, fast evolution and easy accessibility. However, the mitochondrial sequences have been mostly neglected in

  15. miR-27 regulates mitochondrial networks by directly targeting the mitochondrial fission factor.

    Science.gov (United States)

    Tak, Hyosun; Kim, Jihye; Jayabalan, Aravinth Kumar; Lee, Heejin; Kang, Hoin; Cho, Dong-Hyung; Ohn, Takbum; Nam, Suk Woo; Kim, Wook; Lee, Eun Kyung

    2014-11-28

    Mitochondrial morphology is dynamically regulated by forming small, fragmented units or interconnected networks, and this is a pivotal process that is used to maintain mitochondrial homeostasis. Although dysregulation of mitochondrial dynamics is related to the pathogenesis of several human diseases, its molecular mechanism is not fully elucidated. In this study, we demonstrate the potential role of miR-27 in the regulation of mitochondrial dynamics. Mitochondrial fission factor (MFF) mRNA is a direct target of miR-27, whose ectopic expression decreases MFF expression through binding to its 3'-untranslated region. Expression of miR-27 results in the elongation of mitochondria as well as an increased mitochondrial membrane potential and mitochondrial ATP level. Our results suggest that miR-27 is a novel regulator affecting morphological mitochondrial changes by targeting MFF.

  16. Mitochondrial Stress Signaling Promotes Cellular Adaptations

    Directory of Open Access Journals (Sweden)

    Jayne Alexandra Barbour

    2014-01-01

    Full Text Available Mitochondrial dysfunction has been implicated in the aetiology of many complex diseases, as well as the ageing process. Much of the research on mitochondrial dysfunction has focused on how mitochondrial damage may potentiate pathological phenotypes. The purpose of this review is to draw attention to the less well-studied mechanisms by which the cell adapts to mitochondrial perturbations. This involves communication of stress to the cell and successful induction of quality control responses, which include mitophagy, unfolded protein response, upregulation of antioxidant and DNA repair enzymes, morphological changes, and if all else fails apoptosis. The mitochondrion is an inherently stressful environment and we speculate that dysregulation of stress signaling or an inability to switch on these adaptations during times of mitochondrial stress may underpin mitochondrial dysfunction and hence amount to pathological states over time.

  17. Changes in mitochondrial function by lipid peroxidation and their inhibition by biscoclaurin alkaloid

    International Nuclear Information System (INIS)

    Aono, K.; Shiraishi, N.; Arita, T.; Inouye, B.; Nakazawa, T.; Utsumi, K.

    1981-01-01

    During in vitro investigation of changes in mitochondrial function accompanying lipid peroxidation, it was found that cepharanthine, a biscoclaurin alkaloid, protects against such change. Results obtained were as follows: (1) Fe2+ induces lipid peroxidation of isolated mitochondria, resulting in diminished oxidative phosphorylation. (2) This diminishment largely depends on deterioration of ion compartmentation of the membrane and an increase in latent ATPase activity. (3) The Fe2+-induced deterioration in ion compartmentation is inhibited by cepharanthine. (4) Cepharanthine inhibits the mitochondrial lipid peroxidation induced by Fe2+. (5) Cepharanthine inhibits the lipid peroxidation of soybean lecithin liposomes by 60Co-irradiation

  18. Important mitochondrial proteins in human omental adipose tissue show reduced expression in obesity

    Directory of Open Access Journals (Sweden)

    Peter W. Lindinger

    2015-09-01

    Full Text Available Obesity is associated with impaired mitochondrial function. This study compares mitochondrial protein expression in omental fat in obese and non-obese humans. Omental adipose tissue was obtained by surgical biopsy, adipocytes were purified and mitochondria isolated. Using anion-exchange chromatography, SDS-PAGE and mass-spectrometry, 128 proteins with potentially different abundances in patient groups were identified, 62 of the 128 proteins are mainly localized in the mitochondria. Further quantification of 12 of these 62 proteins by immune dot blot analysis revealed four proteins citrate synthase, HADHA, LETM1 and mitofilin being inversely associated with BMI, and mitofilin being inversely correlated with gender.

  19. Important mitochondrial proteins in human omental adipose tissue show reduced expression in obesity.

    Science.gov (United States)

    Lindinger, Peter W; Christe, Martine; Eberle, Alex N; Kern, Beatrice; Peterli, Ralph; Peters, Thomas; Jayawardene, Kamburapola J I; Fearnley, Ian M; Walker, John E

    2015-09-01

    Obesity is associated with impaired mitochondrial function. This study compares mitochondrial protein expression in omental fat in obese and non-obese humans. Omental adipose tissue was obtained by surgical biopsy, adipocytes were purified and mitochondria isolated. Using anion-exchange chromatography, SDS-PAGE and mass-spectrometry, 128 proteins with potentially different abundances in patient groups were identified, 62 of the 128 proteins are mainly localized in the mitochondria. Further quantification of 12 of these 62 proteins by immune dot blot analysis revealed four proteins citrate synthase, HADHA, LETM1 and mitofilin being inversely associated with BMI, and mitofilin being inversely correlated with gender.

  20. Mitochondrial DNA mutations in human tumor cells

    OpenAIRE

    LI, HUI; HONG, ZE-HUI

    2012-01-01

    Mitochondria play significant roles in cellular energy metabolism, free radical generation and apoptosis. The dysfunction of mitochondria is correlated with the origin and progression of tumors; thus, mutations in the mitochondrial genome that affect mitochondrial function may be one of the causal factors of tumorigenesis. Although the role of mitochondrial DNA (mtDNA) mutations in carcinogenesis has been investigated extensively by various approaches, the conclusions remain controversial to ...

  1. Habitual physical activity in mitochondrial disease.

    Directory of Open Access Journals (Sweden)

    Shehnaz Apabhai

    Full Text Available Mitochondrial disease is the most common neuromuscular disease and has a profound impact upon daily life, disease and longevity. Exercise therapy has been shown to improve mitochondrial function in patients with mitochondrial disease. However, no information exists about the level of habitual physical activity of people with mitochondrial disease and its relationship with clinical phenotype.Habitual physical activity, genotype and clinical presentations were assessed in 100 patients with mitochondrial disease. Comparisons were made with a control group individually matched by age, gender and BMI.Patients with mitochondrial disease had significantly lower levels of physical activity in comparison to matched people without mitochondrial disease (steps/day; 6883±3944 vs. 9924±4088, p = 0.001. 78% of the mitochondrial disease cohort did not achieve 10,000 steps per day and 48% were classified as overweight or obese. Mitochondrial disease was associated with less breaks in sedentary activity (Sedentary to Active Transitions, % per day; 13±0.03 vs. 14±0.03, p = 0.001 and an increase in sedentary bout duration (bout lengths/fraction of total sedentary time; 0.206±0.044 vs. 0.187±0.026, p = 0.001. After adjusting for covariates, higher physical activity was moderately associated with lower clinical disease burden (steps/day; r(s = -0.49; 95% CI -0.33, -0.63, P<0.01. There were no systematic differences in physical activity between different genotypes mitochondrial disease.These results demonstrate for the first time that low levels of physical activity are prominent in mitochondrial disease. Combined with a high prevalence of obesity, physical activity may constitute a significant and potentially modifiable risk factor in mitochondrial disease.

  2. Mitochondrial Diseases: Clinical Features- Management of Patients

    Directory of Open Access Journals (Sweden)

    Filiz Koc

    2003-02-01

    Full Text Available Mitochondria are unique organells which their own DNA in cells. Human mitochondrial DNA is circular, double-stranded molecule and small. Because all mitochondria are contributed by the ovum during the formation of the zygote, the mitochondrial genom is transmitted by maternal inheritance. Multisystem disorders such as deafness, cardiomyopathy, miyopathy can be seen in mitochondrial diseases. [Archives Medical Review Journal 2003; 12(0.100: 14-31

  3. Habitual physical activity in mitochondrial disease.

    Science.gov (United States)

    Apabhai, Shehnaz; Gorman, Grainne S; Sutton, Laura; Elson, Joanna L; Plötz, Thomas; Turnbull, Douglass M; Trenell, Michael I

    2011-01-01

    Mitochondrial disease is the most common neuromuscular disease and has a profound impact upon daily life, disease and longevity. Exercise therapy has been shown to improve mitochondrial function in patients with mitochondrial disease. However, no information exists about the level of habitual physical activity of people with mitochondrial disease and its relationship with clinical phenotype. Habitual physical activity, genotype and clinical presentations were assessed in 100 patients with mitochondrial disease. Comparisons were made with a control group individually matched by age, gender and BMI. Patients with mitochondrial disease had significantly lower levels of physical activity in comparison to matched people without mitochondrial disease (steps/day; 6883±3944 vs. 9924±4088, p = 0.001). 78% of the mitochondrial disease cohort did not achieve 10,000 steps per day and 48% were classified as overweight or obese. Mitochondrial disease was associated with less breaks in sedentary activity (Sedentary to Active Transitions, % per day; 13±0.03 vs. 14±0.03, p = 0.001) and an increase in sedentary bout duration (bout lengths/fraction of total sedentary time; 0.206±0.044 vs. 0.187±0.026, p = 0.001). After adjusting for covariates, higher physical activity was moderately associated with lower clinical disease burden (steps/day; r(s) = -0.49; 95% CI -0.33, -0.63, Pphysical activity between different genotypes mitochondrial disease. These results demonstrate for the first time that low levels of physical activity are prominent in mitochondrial disease. Combined with a high prevalence of obesity, physical activity may constitute a significant and potentially modifiable risk factor in mitochondrial disease.

  4. Piracetam improves mitochondrial dysfunction following oxidative stress

    OpenAIRE

    Keil, Uta; Scherping, Isabel; Hauptmann, Susanne; Schuessel, Katin; Eckert, Anne; Müller, Walter E

    2005-01-01

    Mitochondrial dysfunction including decrease of mitochondrial membrane potential and reduced ATP production represents a common final pathway of many conditions associated with oxidative stress, for example, hypoxia, hypoglycemia, and aging.Since the cognition-improving effects of the standard nootropic piracetam are usually more pronounced under such pathological conditions and young healthy animals usually benefit little by piracetam, the effect of piracetam on mitochondrial dysfunction fol...

  5. Mitochondrial Dynamics in Cardiovascular Health and Disease

    OpenAIRE

    Ong, Sang-Bing; Hall, Andrew R.; Hausenloy, Derek J.

    2013-01-01

    Significance: Mitochondria are dynamic organelles capable of changing their shape and distribution by undergoing either fission or fusion. Changes in mitochondrial dynamics, which is under the control of specific mitochondrial fission and fusion proteins, have been implicated in cell division, embryonic development, apoptosis, autophagy, and metabolism. Although the machinery for modulating mitochondrial dynamics is present in the cardiovascular system, its function there has only recently be...

  6. Common effects of lithium and valproate on mitochondrial functions: protection against methamphetamine-induced mitochondrial damage.

    Science.gov (United States)

    Bachmann, Rosilla F; Wang, Yun; Yuan, Peixiong; Zhou, Rulun; Li, Xiaoxia; Alesci, Salvatore; Du, Jing; Manji, Husseini K

    2009-07-01

    Accumulating evidence suggests that mitochondrial dysfunction plays a critical role in the progression of a variety of neurodegenerative and psychiatric disorders. Thus, enhancing mitochondrial function could potentially help ameliorate the impairments of neural plasticity and cellular resilience associated with a variety of neuropsychiatric disorders. A series of studies was undertaken to investigate the effects of mood stabilizers on mitochondrial function, and against mitochondrially mediated neurotoxicity. We found that long-term treatment with lithium and valproate (VPA) enhanced cell respiration rate. Furthermore, chronic treatment with lithium or VPA enhanced mitochondrial function as determined by mitochondrial membrane potential, and mitochondrial oxidation in SH-SY5Y cells. In-vivo studies showed that long-term treatment with lithium or VPA protected against methamphetamine (Meth)-induced toxicity at the mitochondrial level. Furthermore, these agents prevented the Meth-induced reduction of mitochondrial cytochrome c, the mitochondrial anti-apoptotic Bcl-2/Bax ratio, and mitochondrial cytochrome oxidase (COX) activity. Oligoarray analysis demonstrated that the gene expression of several proteins related to the apoptotic pathway and mitochondrial functions were altered by Meth, and these changes were attenuated by treatment with lithium or VPA. One of the genes, Bcl-2, is a common target for lithium and VPA. Knock-down of Bcl-2 with specific Bcl-2 siRNA reduced the lithium- and VPA-induced increases in mitochondrial oxidation. These findings illustrate that lithium and VPA enhance mitochondrial function and protect against mitochondrially mediated toxicity. These agents may have potential clinical utility in the treatment of other diseases associated with impaired mitochondrial function, such as neurodegenerative diseases and schizophrenia.

  7. Inner-membrane proteins PMI/TMEM11 regulate mitochondrial morphogenesis independently of the DRP1/MFN fission/fusion pathways.

    Science.gov (United States)

    Rival, Thomas; Macchi, Marc; Arnauné-Pelloquin, Laetitia; Poidevin, Mickael; Maillet, Frédéric; Richard, Fabrice; Fatmi, Ahmed; Belenguer, Pascale; Royet, Julien

    2011-03-01

    Mitochondria are highly dynamic organelles that can change in number and morphology during cell cycle, development or in response to extracellular stimuli. These morphological dynamics are controlled by a tight balance between two antagonistic pathways that promote fusion and fission. Genetic approaches have identified a cohort of conserved proteins that form the core of mitochondrial remodelling machineries. Mitofusins (MFNs) and OPA1 proteins are dynamin-related GTPases that are required for outer- and inner-mitochondrial membrane fusion respectively whereas dynamin-related protein 1 (DRP1) is the master regulator of mitochondrial fission. We demonstrate here that the Drosophila PMI gene and its human orthologue TMEM11 encode mitochondrial inner-membrane proteins that regulate mitochondrial morphogenesis. PMI-mutant cells contain a highly condensed mitochondrial network, suggesting that PMI has either a pro-fission or an anti-fusion function. Surprisingly, however, epistatic experiments indicate that PMI shapes the mitochondria through a mechanism that is independent of drp1 and mfn. This shows that mitochondrial networks can be shaped in higher eukaryotes by at least two separate pathways: one PMI-dependent and one DRP1/MFN-dependent.

  8. Physiological Levels of Nitric Oxide Diminish Mitochondrial Superoxide. Potential Role of Mitochondrial Dinitrosyl Iron Complexes and Nitrosothiols

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    Sergey I. Dikalov

    2017-11-01

    Full Text Available Mitochondria are the major source of superoxide radicals and superoxide overproduction contributes to cardiovascular diseases and metabolic disorders. Endothelial dysfunction and diminished nitric oxide levels are early steps in the development of these pathological conditions. It is known that physiological production of nitric oxide reduces oxidative stress and inflammation, however, the precise mechanism of “antioxidant” effect of nitric oxide is not clear. In this work we tested the hypothesis that physiological levels of nitric oxide diminish mitochondrial superoxide production without inhibition of mitochondrial respiration. In order to test this hypothesis we analyzed effect of low physiological fluxes of nitric oxide (20 nM/min on superoxide and hydrogen peroxide production by ESR spin probes and Amplex Red in isolated rat brain mitochondria. Indeed, low levels of nitric oxide substantially attenuated both basal and antimycin A-stimulated production of reactive oxygen species in the presence of succinate or glutamate/malate as mitochondrial substrates. Furthermore, slow releasing NO donor DPTA-NONOate (100 μM did not change oxygen consumption in State 4 and State 3. However, the NO-donor strongly inhibited oxygen consumption in the presence of uncoupling agent CCCP, which is likely associated with inhibition of the over-reduced complex IV in uncoupled mitochondria. We have examined accumulation of dinitrosyl iron complexes and nitrosothiols in mitochondria treated with fast-releasing NO donor MAHMA NONOate (10 μM for 30 min until complete release of NO. Following treatment with NO donor, mitochondria were frozen for direct detection of dinitrosyl iron complexes using Electron Spin Resonance (ESR while accumulation of nitrosothiols was measured by ferrous-N-Methyl-D-glucamine dithiocarbamate complex, Fe(MGD2, in lysed mitochondria. Treatment of mitochondria with NO-donor gave rise to ESR signal of dinitrosyl iron complexes while ESR

  9. Natural variation in life history and aging phenotypes is associated with mitochondrial DNA deletion frequency in Caenorhabditis briggsae

    Directory of Open Access Journals (Sweden)

    Smith Samson W

    2011-01-01

    Full Text Available Abstract Background Mutations that impair mitochondrial functioning are associated with a variety of metabolic and age-related disorders. A barrier to rigorous tests of the role of mitochondrial dysfunction in aging processes has been the lack of model systems with relevant, naturally occurring mitochondrial genetic variation. Toward the goal of developing such a model system, we studied natural variation in life history, metabolic, and aging phenotypes as it relates to levels of a naturally-occurring heteroplasmic mitochondrial ND5 deletion recently discovered to segregate among wild populations of the soil nematode, Caenorhabditis briggsae. The normal product of ND5 is a central component of the mitochondrial electron transport chain and integral to cellular energy metabolism. Results We quantified significant variation among C. briggsae isolates for all phenotypes measured, only some of which was statistically associated with isolate-specific ND5 deletion frequency. We found that fecundity-related traits and pharyngeal pumping rate were strongly inversely related to ND5 deletion level and that C. briggsae isolates with high ND5 deletion levels experienced a tradeoff between early fecundity and lifespan. Conversely, oxidative stress resistance was only weakly associated with ND5 deletion level while ATP content was unrelated to deletion level. Finally, mean levels of reactive oxygen species measured in vivo showed a significant non-linear relationship with ND5 deletion level, a pattern that may be driven by among-isolate variation in antioxidant or other compensatory mechanisms. Conclusions Our findings suggest that the ND5 deletion may adversely affect fitness and mitochondrial functioning while promoting aging in natural populations, and help to further establish this species as a useful model for explicit tests of hypotheses in aging biology and mitochondrial genetics.

  10. Targeted Modification of Mitochondrial ROS Production Converts High Glucose-Induced Cytotoxicity to Cytoprotection: Effects on Anesthetic Preconditioning.

    Science.gov (United States)

    Sedlic, Filip; Muravyeva, Maria Y; Sepac, Ana; Sedlic, Marija; Williams, Anna Marie; Yang, Meiying; Bai, Xiaowen; Bosnjak, Zeljko J

    2017-01-01

    Contradictory reports on the effects of diabetes and hyperglycemia on myocardial infarction range from cytotoxicity to cytoprotection. The study was designed to investigate acute effects of high glucose-driven changes in mitochondrial metabolism and osmolarity on adaptive mechanisms and resistance to oxidative stress of isolated rat cardiomyocytes. We examined the effects of high glucose on several parameters of mitochondrial bioenergetics, including changes in oxygen consumption, mitochondrial membrane potential, and NAD(P)H fluorometry. Effects of high glucose on the endogenous cytoprotective mechanisms elicited by anesthetic preconditioning (APC) and the mediators of cell injury were also tested. These experiments included real-time measurements of reactive oxygen species (ROS) production and mitochondrial permeability transition pore (mPTP) opening in single cells by laser scanning fluorescence confocal microscopy, and cell survival assay. High glucose rapidly enhanced mitochondrial energy metabolism, observed by increase in NAD(P)H fluorescence intensity, oxygen consumption, and mitochondrial membrane potential. This substantially elevated production of ROS, accelerated opening of the mPTP, and decreased survival of cells exposed to oxidative stress. Abrogation of high glucose-induced mitochondrial hyperpolarization with 2,4 dinitrophenol (DNP) significantly, but not completely, attenuated ROS production to a level similar to hyperosmotic mannitol control. DNP treatment reversed high glucose-induced cytotoxicity to cytoprotection. Hyperosmotic mannitol treatment also induced cytoprotection. High glucose abrogated APC-induced mitochondrial depolarization, delay in mPTP opening and cytoprotection. In conclusion, high glucose-induced mitochondrial hyperpolarization abolishes APC and augments cell injury. Attenuation of high glucose-induced ROS production by eliminating mitochondrial hyperpolarization protects cardiomyocytes. J. Cell. Physiol. 232: 216-224, 2017

  11. Tempol, a Superoxide Dismutase Mimetic Agent, Ameliorates Cisplatin-Induced Nephrotoxicity through Alleviation of Mitochondrial Dysfunction in Mice

    Science.gov (United States)

    Ahmed, Lamiaa A.; Shehata, Nagwa I.; Abdelkader, Noha F.; Khattab, Mahmoud M.

    2014-01-01

    Background Mitochondrial dysfunction is a crucial mechanism by which cisplatin, a potent chemotherapeutic agent, causes nephrotoxicity where mitochondrial electron transport complexes are shifted mostly toward imbalanced reactive oxygen species versus energy production. In the present study, the protective role of tempol, a membrane-permeable superoxide dismutase mimetic agent, was evaluated on mitochondrial dysfunction and the subsequent damage induced by cisplatin nephrotoxicity in mice. Methods and Findings Nephrotoxicity was assessed 72 h after a single i.p. injection of cisplatin (25 mg/kg) with or without oral administration of tempol (100 mg/kg/day). Serum creatinine and urea as well as glucosuria and proteinuria were evaluated. Both kidneys were isolated for estimation of oxidative stress markers, adenosine triphosphate (ATP) content and caspase-3 activity. Moreover, mitochondrial oxidative phosphorylation capacity, complexes I–IV activities and mitochondrial nitric oxide synthase (mNOS) protein expression were measured along with histological examinations of renal tubular damage and mitochondrial ultrastructural changes. Tempol was effective against cisplatin-induced elevation of serum creatinine and urea as well as glucosuria and proteinuria. Moreover, pretreatment with tempol notably inhibited cisplatin-induced oxidative stress and disruption of mitochondrial function by restoring mitochondrial oxidative phosphorylation, complexes I and III activities, mNOS protein expression and ATP content. Tempol also provided significant protection against apoptosis, tubular damage and mitochondrial ultrastructural changes. Interestingly, tempol did not interfere with the cytotoxic effect of cisplatin against the growth of solid Ehrlich carcinoma. Conclusion This study highlights the potential role of tempol in inhibiting cisplatin-induced nephrotoxicity without affecting its antitumor activity via amelioration of oxidative stress and mitochondrial dysfunction

  12. Tempol, a superoxide dismutase mimetic agent, ameliorates cisplatin-induced nephrotoxicity through alleviation of mitochondrial dysfunction in mice.

    Directory of Open Access Journals (Sweden)

    Lamiaa A Ahmed

    Full Text Available Mitochondrial dysfunction is a crucial mechanism by which cisplatin, a potent chemotherapeutic agent, causes nephrotoxicity where mitochondrial electron transport complexes are shifted mostly toward imbalanced reactive oxygen species versus energy production. In the present study, the protective role of tempol, a membrane-permeable superoxide dismutase mimetic agent, was evaluated on mitochondrial dysfunction and the subsequent damage induced by cisplatin nephrotoxicity in mice.Nephrotoxicity was assessed 72 h after a single i.p. injection of cisplatin (25 mg/kg with or without oral administration of tempol (100 mg/kg/day. Serum creatinine and urea as well as glucosuria and proteinuria were evaluated. Both kidneys were isolated for estimation of oxidative stress markers, adenosine triphosphate (ATP content and caspase-3 activity. Moreover, mitochondrial oxidative phosphorylation capacity, complexes I-IV activities and mitochondrial nitric oxide synthase (mNOS protein expression were measured along with histological examinations of renal tubular damage and mitochondrial ultrastructural changes. Tempol was effective against cisplatin-induced elevation of serum creatinine and urea as well as glucosuria and proteinuria. Moreover, pretreatment with tempol notably inhibited cisplatin-induced oxidative stress and disruption of mitochondrial function by restoring mitochondrial oxidative phosphorylation, complexes I and III activities, mNOS protein expression and ATP content. Tempol also provided significant protection against apoptosis, tubular damage and mitochondrial ultrastructural changes. Interestingly, tempol did not interfere with the cytotoxic effect of cisplatin against the growth of solid Ehrlich carcinoma.This study highlights the potential role of tempol in inhibiting cisplatin-induced nephrotoxicity without affecting its antitumor activity via amelioration of oxidative stress and mitochondrial dysfunction.

  13. Mitochondrial DNA: A Blind Spot in Neuroepigenetics.

    Science.gov (United States)

    Manev, Hari; Dzitoyeva, Svetlana; Chen, Hu

    2012-04-01

    Neuroepigenetics, which includes nuclear DNA modifications such as 5-methylcytosine and 5-hydoxymethylcytosine and modifications of nuclear proteins such as histones, is emerging as the leading field in molecular neuroscience. Historically, a functional role for epigenetic mechanisms, including in neuroepigenetics, has been sought in the area of the regulation of nuclear transcription. However, one important compartment of mammalian cell DNA, different from nuclear but equally important for physiological and pathological processes (including in the brain), mitochondrial DNA has for the most part not had a systematic epigenetic characterization. The importance of mitochondria and mitochondrial DNA (particularly its mutations) in central nervous system physiology and pathology has long been recognized. Only recently have mechanisms of mitochondrial DNA methylation and hydroxymethylation, including the discovery of mitochondrial DNA-methyltransferases and the presence and the functionality of 5-methylcytosine and 5-hydroxymethylcytosine in mitochondrial DNA (e.g., in modifying the transcription of mitochondrial genome), been unequivocally recognized as a part of mammalian mitochondrial physiology. Here we summarize for the first time evidence supporting the existence of these mechanisms and we propose the term "mitochondrial epigenetics" to be used when referring to them. Currently, neuroepigenetics does not include mitochondrial epigenetics - a gap that we expect to close in the near future.

  14. Role of polyhydroxybutyrate in mitochondrial calcium uptake

    Science.gov (United States)

    Smithen, Matthew; Elustondo, Pia A.; Winkfein, Robert; Zakharian, Eleonora; Abramov, Andrey Y.; Pavlov, Evgeny

    2013-01-01

    Polyhydroxybutyrate (PHB) is a biological polymer which belongs to the class of polyesters and is ubiquitously present in all living organisms. Mammalian mitochondrial membranes contain PHB consisting of up to 120 hydroxybutyrate residues. Roles played by PHB in mammalian mitochondria remain obscure. It was previously demonstrated that PHB of the size similar to one found in mitochondria mediates calcium transport in lipid bilayer membranes. We hypothesized that the presence of PHB in mitochondrial membrane might play a significant role in mitochondrial calcium transport. To test this, we investigated how the induction of PHB hydrolysis affects mitochondrial calcium transport. Mitochondrial PHB was altered enzymatically by targeted expression of bacterial PHB hydrolyzing enzyme (PhaZ7) in mitochondria of mammalian cultured cells. The expression of PhaZ7 induced changes in mitochondrial metabolism resulting in decreased mitochondrial membrane potential in HepG2 but not in U87 and HeLa cells. Furthermore, it significantly inhibited mitochondrial calcium uptake in intact HepG2, U87 and HeLa cells stimulated by the ATP or by the application of increased concentrations of calcium to the digitonin permeabilized cells. Calcium uptake in PhaZ7 expressing cells was restored by mimicking calcium uniporter properties with natural electrogenic calcium ionophore - ferutinin. We propose that PHB is a previously unrecognized important component of the mitochondrial calcium uptake system. PMID:23702223

  15. The effect of mitochondrial calcium uniporter on mitochondrial fission in hippocampus cells ischemia/reperfusion injury

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lantao; Li, Shuhong; Wang, Shilei, E-mail: wshlei@aliyun.com; Yu, Ning; Liu, Jia

    2015-06-05

    The mitochondrial calcium uniporter (MCU) transports free Ca{sup 2+} into the mitochondrial matrix, maintaining Ca{sup 2+} homeostasis, thus regulates the mitochondrial morphology. Previous studies have indicated that there was closely crosstalk between MCU and mitochondrial fission during the process of ischemia/reperfusion injury. This study constructed a hypoxia reoxygenation model using primary hippocampus neurons to mimic the cerebral ischemia/reperfusion injury and aims to explore the exactly effect of MCU on the mitochondrial fission during the process of ischemia/reperfusion injury and so as the mechanisms. Our results found that the inhibitor of the MCU, Ru360, decreased mitochondrial Ca{sup 2+} concentration, suppressed the expression of mitochondrial fission protein Drp1, MIEF1 and Fis1, and thus improved mitochondrial morphology significantly. Whereas spermine, the agonist of the MCU, had no significant impact compared to the I/R group. This study demonstrated that the MCU regulates the process of mitochondrial fission by controlling the Ca{sup 2+} transport, directly upregulating mitochondrial fission proteins Drp1, Fis1 and indirectly reversing the MIEF1-induced mitochondrial fusion. It also provides new targets for brain protection during ischemia/reperfusion injury. - Highlights: • We study MCU with primary neuron culture. • MCU induces mitochondrial fission. • MCU reverses MIEF1 effect.

  16. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS mediated cardiomyocyte hypertrophy

    NARCIS (Netherlands)

    Tigchelaar, Wardit; Yu, Hongjuan; De Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Sillje, Herman H W

    2015-01-01

    Recently, a genetic variant in the mitochondrial exo/endo nuclease EXOG, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and

  17. The mitochondrial transcription factor A functions in mitochondrial base excision repair

    DEFF Research Database (Denmark)

    Canugovi, Chandrika; Maynard, Scott; Bayne, Anne-Cécile V

    2010-01-01

    Mitochondrial transcription factor A (TFAM) is an essential component of mitochondrial nucleoids. TFAM plays an important role in mitochondrial transcription and replication. TFAM has been previously reported to inhibit nucleotide excision repair (NER) in vitro but NER has not yet been detected i...

  18. Antibiotic Trapping by Plasmid-Encoded CMY-2 beta-Lactamase Combined with Reduced Outer Membrane Permeability as a Mechanism of Carbapenem Resistance in Escherichia coli

    NARCIS (Netherlands)

    Goessens, W.H.F.; van der Bij, A.K.; van Boxtel, R.; Pitout, J.D.D.; van Ulsen, J.P.; Melles, D.C.; Tommassen, J.

    2013-01-01

    A liver transplant patient was admitted with cholangitis, for which meropenem therapy was started. Initial cultures showed a carbapenem-susceptible (CS) Escherichia coli strain, but during admission, a carbapenem-resistant (CR) E. coli strain was isolated. Analysis of the outer membrane protein

  19. Antibiotic trapping by plasmid-encoded cmy-2-lactamase combined with reduced outer membrane permeability as a mechanism of carbapenem resistance in escherichia coli

    NARCIS (Netherlands)

    W.H.F. Goessens (Wil); A.K. van der Bij (Akke); R. van Boxtel (Ria); J.D.D. Pitout (J. D D); P. van Ulsen (Peter); D.C. Melles (Damian); J. Tommassen (Jan)

    2013-01-01

    textabstractA liver transplant patient was admitted with cholangitis, for which meropenem therapy was started. Initial cultures showed a carbapenem-susceptible (CS) Escherichia coli strain, but during admission, a carbapenem-resistant (CR) E. coli strain was isolated. Analysis of the outer membrane

  20. EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines.

    Science.gov (United States)

    Dikalov, Sergey I; Kirilyuk, Igor A; Voinov, Maxim; Grigor'ev, Igor A

    2011-04-01

    Superoxide (O₂ⁱ⁻) has been implicated in the pathogenesis of many human diseases, but detection of the O(2)(•-) radicals in biological systems is limited due to inefficiency of O₂ⁱ⁻ spin trapping and lack of site-specific information. This work studied production of extracellular, intracellular and mitochondrial O₂ⁱ⁻ in neutrophils, cultured endothelial cells and isolated mitochondria using a new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O₂ⁱ⁻, producing stable nitroxides and allowing site-specific cO₂ⁱ⁻ detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O₂ⁱ⁻. Inhibition of EPR signal by SOD2 over-expression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O₂ⁱ⁻ both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected an increase in cytoplasm O₂ⁱ⁻ stimulated by PMA, but only CM-H and mitoTEMPO-H showed an increase in rotenone-induced mitochondrial O₂ⁱ⁻. These data show that a new set of hydroxylamine spin probes provide unique information about site-specific production of the O₂ⁱ⁻ radical in extracellular or intracellular compartments, cytoplasm or mitochondria.

  1. Mitochondrial flash as a novel biomarker of mitochondrial respiration in the heart.

    Science.gov (United States)

    Gong, Guohua; Liu, Xiaoyun; Zhang, Huiliang; Sheu, Shey-Shing; Wang, Wang

    2015-10-01

    Mitochondrial respiration through electron transport chain (ETC) activity generates ATP and reactive oxygen species in eukaryotic cells. The modulation of mitochondrial respiration in vivo or under physiological conditions remains elusive largely due to the lack of appropriate approach to monitor ETC activity in a real-time manner. Here, we show that ETC-coupled mitochondrial flash is a novel biomarker for monitoring mitochondrial respiration under pathophysiological conditions in cultured adult cardiac myocyte and perfused beating heart. Through real-time confocal imaging, we follow the frequency of a transient bursting fluorescent signal, named mitochondrial flash, from individual mitochondria within intact cells expressing a mitochondrial matrix-targeted probe, mt-cpYFP (mitochondrial-circularly permuted yellow fluorescent protein). This mt-cpYFP recorded mitochondrial flash has been shown to be composed of a major superoxide signal with a minor alkalization signal within the mitochondrial matrix. Through manipulating physiological substrates for mitochondrial respiration, we find a close coupling between flash frequency and the ETC electron flow, as measured by oxygen consumption rate in cardiac myocyte. Stimulating electron flow under physiological conditions increases flash frequency. On the other hand, partially block or slowdown electron flow by inhibiting the F0F1 ATPase, which represents a pathological condition, transiently increases then decreases flash frequency. Limiting electron entrance at complex I by knocking out Ndufs4, an assembling subunit of complex I, suppresses mitochondrial flash activity. These results suggest that mitochondrial electron flow can be monitored by real-time imaging of mitochondrial flash. The mitochondrial flash frequency could be used as a novel biomarker for mitochondrial respiration under physiological and pathological conditions. Copyright © 2015 the American Physiological Society.

  2. Mitochondrial tRNA cleavage by tRNA-targeting ribonuclease causes mitochondrial dysfunction observed in mitochondrial disease

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Tetsuhiro, E-mail: atetsu@mail.ecc.u-tokyo.ac.jp; Shimizu, Ayano; Takahashi, Kazutoshi; Hidaka, Makoto; Masaki, Haruhiko, E-mail: amasaki@mail.ecc.u-tokyo.ac.jp

    2014-08-15

    Highlights: • MTS-tagged ribonuclease was translocated successfully to the mitochondrial matrix. • MTS-tagged ribonuclease cleaved mt tRNA and reduced COX activity. • Easy and reproducible method of inducing mt tRNA dysfunction. - Abstract: Mitochondrial DNA (mtDNA) is a genome possessed by mitochondria. Since reactive oxygen species (ROS) are generated during aerobic respiration in mitochondria, mtDNA is commonly exposed to the risk of DNA damage. Mitochondrial disease is caused by mitochondrial dysfunction, and mutations or deletions on mitochondrial tRNA (mt tRNA) genes are often observed in mtDNA of patients with the disease. Hence, the correlation between mt tRNA activity and mitochondrial dysfunction has been assessed. Then, cybrid cells, which are constructed by the fusion of an enucleated cell harboring altered mtDNA with a ρ{sup 0} cell, have long been used for the analysis due to difficulty in mtDNA manipulation. Here, we propose a new method that involves mt tRNA cleavage by a bacterial tRNA-specific ribonuclease. The ribonuclease tagged with a mitochondrial-targeting sequence (MTS) was successfully translocated to the mitochondrial matrix. Additionally, mt tRNA cleavage, which resulted in the decrease of cytochrome c oxidase (COX) activity, was observed.

  3. A Peptidomimetic Antibiotic Targets Outer Membrane Proteins and Disrupts Selectively the Outer Membrane in Escherichia coli.

    Science.gov (United States)

    Urfer, Matthias; Bogdanovic, Jasmina; Lo Monte, Fabio; Moehle, Kerstin; Zerbe, Katja; Omasits, Ulrich; Ahrens, Christian H; Pessi, Gabriella; Eberl, Leo; Robinson, John A

    2016-01-22

    Increasing antibacterial resistance presents a major challenge in antibiotic discovery. One attractive target in Gram-negative bacteria is the unique asymmetric outer membrane (OM), which acts as a permeability barrier that protects the cell from external stresses, such as the presence of antibiotics. We describe a novel β-hairpin macrocyclic peptide JB-95 with potent antimicrobial activity against Escherichia coli. This peptide exhibits no cellular lytic activity, but electron microscopy and fluorescence studies reveal an ability to selectively disrupt the OM but not the inner membrane of E. coli. The selective targeting of the OM probably occurs through interactions of JB-95 with selected β-barrel OM proteins, including BamA and LptD as shown by photolabeling experiments. Membrane proteomic studies reveal rapid depletion of many β-barrel OM proteins from JB-95-treated E. coli, consistent with induction of a membrane stress response and/or direct inhibition of the Bam folding machine. The results suggest that lethal disruption of the OM by JB-95 occurs through a novel mechanism of action at key interaction sites within clusters of β-barrel proteins in the OM. These findings open new avenues for developing antibiotics that specifically target β-barrel proteins and the integrity of the Gram-negative OM. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Living in the past: phylogeography and population histories of Indo-Pacific wrasses (genus Halichoeres in shallow lagoons versus outer reef slopes.

    Directory of Open Access Journals (Sweden)

    William B Ludt

    Full Text Available Sea level fluctuations during glacial cycles affect the distribution of shallow marine biota, exposing the continental shelf on a global scale, and displacing coral reef habitat to steep slopes on oceanic islands. In these circumstances we expect that species inhabiting lagoons should show shallow genetic architecture relative to species inhabiting more stable outer reefs. Here we test this expectation on an ocean-basin scale with four wrasses (genus Halichoeres: H. claudia (N = 194, with ocean-wide distribution and H. ornatissimus (N = 346, a Hawaiian endemic inhabit seaward reef slopes, whereas H. trimaculatus (N = 239 and H. margaritaceus (N = 118 inhabit lagoons and shallow habitats throughout the Pacific. Two mitochondrial markers (cytochrome oxidase I and control region were sequenced to resolve population structure and history of each species. Haplotype and nucleotide diversity were similar among all four species. The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations. Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations shallower histories in the outer slope species. We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands. In contrast, outer reef slope species have homogeneous and well-connected populations through their entire ranges regardless of sea level fluctuations. These findings contradict the hypothesis that shallow species are less genetically diverse as a consequence of glacial cycles.

  5. Roles of dynamin-related protein 1 in the regulation of mitochondrial fission and apoptosis in response to UV stimuli

    Science.gov (United States)

    Zhang, Zhenzhen; Feng, Jie; Wu, Shengnan

    2011-03-01

    Mitochondria are dynamic structures that frequently divide and fuse with one another to form interconnecting network. This network disintegrates into punctiform organelles during apoptosis. However, it remains unclear whether this event has a significant impact on the rate of cell death or only accompanies apoptosis as an epiphenomenon. In this study, we investigate the role of dynamin-related protein 1 (Drp1), a large GTPase that mediates outer mitochondrial membrane fission, in mitochondrial morphology and apoptosis in response to UV irradiation in human lung adenocarcinoma cells (ASTC-a-1) and HeLa cells. Using time-lapse fluorescent imaging, we find that Drp1 primarily distributes in cytosol under physiological conditions. After UV treatment, Drp1 translocates from cytosol to mitochondria, indicating the enhancement of Drp1 mitochondrial accumulation. Down-regulation of Drp1 by shRNA inhibits UV-induced apoptosis. Our results suggest that Drp1 is involved in the regulation of transition from a reticulo-tubular to a punctiform mitochondrial phenotype and mitochondrial fission plays an important role in UV-induced apoptosis.

  6. Targeted Transgenic Overexpression of Mitochondrial Thymidine Kinase (TK2) Alters Mitochondrial DNA (mtDNA) and Mitochondrial Polypeptide Abundance : Transgenic TK2, mtDNA, and Antiretrovirals

    OpenAIRE

    Hosseini, Seyed H.; Kohler, James J.; Haase, Chad P.; Tioleco, Nina; Stuart, Tami; Keebaugh, Erin; Ludaway, Tomika; Russ, Rodney; Green, Elgin; Long, Robert; Wang, Liya; Eriksson, Staffan; Lewis, William

    2007-01-01

    Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-γ. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK...

  7. Increased androgen levels in rats impair glucose-stimulated insulin secretion through disruption of pancreatic beta cell mitochondrial function.

    Science.gov (United States)

    Wang, Hongdong; Wang, Xiaping; Zhu, Yunxia; Chen, Fang; Sun, Yujie; Han, Xiao

    2015-11-01

    Although insulin resistance is recognized to contribute to the reproductive and metabolic phenotypes of polycystic ovary syndrome (PCOS), pancreatic beta cell dysfunction plays an essential role in the progression from PCOS to the development of type 2 diabetes. However, the role of insulin secretory abnormalities in PCOS has received little attention. In addition, the precise changes in beta cells and the underlying mechanisms remain unclear. In this study, we therefore attempted to elucidate potential mechanisms involved in beta cell alterations in a rat model of PCOS. Glucose-induced insulin secretion was measured in islets isolated from DHT-treated and control rats. Oxygen consumption rate (OCR), ATP production, and mitochondrial copy number were assayed to evaluate mitochondrial function. Glucose-stimulated insulin secretion is significantly decreased in islets from DHT-treated rats. On the other hand, significant reductions are observed in the expression levels of several key genes involved in mitochondrial biogenesis and in mitochondrial OCR and ATP production in DHT-treated rat islets. Meanwhile, we found that androgens can directly impair beta cell function by inducing mitochondrial dysfunction in vitro in an androgen receptor dependent manner. For the first time, our study demonstrates that increased androgens in female rats can impair glucose-stimulated insulin secretion partly through disruption of pancreatic beta cell mitochondrial function. This work has significance for hyperandrogenic women with PCOS: excess activation of the androgen receptor by androgens may provoke beta cell dysfunction via mitochondrial dysfunction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. NMR structure of temporin-1 ta in lipopolysaccharide micelles: mechanistic insight into inactivation by outer membrane.

    Directory of Open Access Journals (Sweden)

    Rathi Saravanan

    Full Text Available BACKGROUND: Antimicrobial peptides (AMPs play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a specialized lipid called lipopolysaccharide (LPS. The LPS layer is an efficient permeability barrier against anti-bacterial agents including AMPs. As a mode of protection, LPS can induce self associations of AMPs rendering them inactive. Temporins are a group of short-sized AMPs isolated from frog skin, and many of them are inactive against Gram negative bacteria as a result of their self-association in the LPS-outer membrane. PRINCIPAL FINDINGS: Using NMR spectroscopy, we have determined atomic resolution structure and characterized localization of temporin-1Ta or TA (FLPLIGRVLSGIL-amide in LPS micelles. In LPS micelles, TA adopts helical conformation for residues L4-I12, while residues F1-L3 are found to be in extended conformations. The aromatic sidechain of residue F1 is involved in extensive packing interactions with the sidechains of residues P3, L4 and I5. Interestingly, a number of long-range NOE contacts have been detected between the N-terminal residues F1, P3 with the C-terminal residues S10, I12, L13 of TA in LPS micelles. Saturation transfer difference (STD NMR studies demonstrate close proximity of residues including F1, L2, P3, R7, S10 and L13 with the LPS micelles. Notably, the LPS bound structure of TA shows differences with the structures of TA determined in DPC and SDS detergent micelles. SIGNIFICANCE: We propose that TA, in LPS lipids, forms helical oligomeric structures employing N- and C-termini residues. Such oligomeric structures may not be translocated across the outer membrane; resulting in the inactivation of the AMP. Importantly, the results of our studies will be useful for the development of antimicrobial agents with a

  9. Comparative transcriptional and translational analysis of leptospiral outer membrane protein expression in response to temperature.

    Directory of Open Access Journals (Sweden)

    Miranda Lo

    Full Text Available BACKGROUND: Leptospirosis is a global zoonosis affecting millions of people annually. Transcriptional changes in response to temperature were previously investigated using microarrays to identify genes potentially expressed upon host entry. Past studies found that various leptospiral outer membrane proteins are differentially expressed at different temperatures. However, our microarray studies highlighted a divergence between protein abundance and transcript levels for some proteins. Given the abundance of post-transcriptional expression control mechanisms, this finding highlighted the importance of global protein analysis systems. METHODOLOGY/PRINCIPAL FINDINGS: To complement our previous transcription study, we evaluated differences in the proteins of the leptospiral outer membrane fraction in response to temperature upshift. Outer membrane protein-enriched fractions from Leptospira interrogans grown at 30 degrees C or overnight upshift to 37 degrees C were isolated and the relative abundance of each protein was determined by iTRAQ analysis coupled with two-dimensional liquid chromatography and tandem mass spectrometry (2-DLC/MS-MS. We identified 1026 proteins with 99% confidence; 27 and 66 were present at elevated and reduced abundance respectively. Protein abundance changes were compared with transcriptional differences determined from the microarray studies. While there was some correlation between the microarray and iTRAQ data, a subset of genes that showed no differential expression by microarray was found to encode temperature-regulated proteins. This set of genes is of particular interest as it is likely that regulation of their expression occurs post-transcriptionally, providing an opportunity to develop hypotheses about the molecular dynamics of the outer membrane of Leptospira in response to changing environments. CONCLUSIONS/SIGNIFICANCE: This is the first study to compare transcriptional and translational responses to temperature

  10. Fluctuation-driven mechanotransduction regulates mitochondrial-network structure and function

    Science.gov (United States)

    Bartolák-Suki, Erzsébet; Imsirovic, Jasmin; Parameswaran, Harikrishnan; Wellman, Tyler J.; Martinez, Nuria; Allen, Philip G.; Frey, Urs; Suki, Béla

    2015-10-01

    Cells can be exposed to irregular mechanical fluctuations, such as those arising from changes in blood pressure. Here, we report that ATP production, assessed through changes in mitochondrial membrane potential, is downregulated in vascular smooth muscle cells in culture exposed to monotonous stretch cycles when compared with cells exposed to a variable cyclic stretch that incorporates physiological levels of cycle-by-cycle variability in stretch amplitude. Variable stretch enhances ATP production by increasing the expression of ATP synthase’s catalytic domain, cytochrome c oxidase and its tyrosine phosphorylation, mitofusins and PGC-1α. Such a fluctuation-driven mechanotransduction mechanism is mediated by motor proteins and by the enhancement of microtubule-, actin- and mitochondrial-network complexity. We also show that, in aorta rings isolated from rats, monotonous stretch downregulates--whereas variable stretch maintains--physiological vessel-wall contractility through mitochondrial ATP production. Our results have implications for ATP-dependent and mechanosensitive intracellular processes.

  11. Lactate dehydrogenase is not a mitochondrial enzyme in human and mouse vastus lateralis muscle

    DEFF Research Database (Denmark)

    Rasmussen, Hans N; van Hall, Gerrit; Rasmussen, Ulla F

    2002-01-01

    The presence of lactate dehydrogenase in skeletal muscle mitochondria was investigated to clarify whether lactate is a possible substrate for mitochondrial respiration. Mitochondria were prepared from 100 mg samples of human and mouse vastus lateralis muscle. All fractions from the preparation...... procedure were assayed for marker enzymes and lactate dehydrogenase (LDH). The mitochondrial fraction contained no LDH activity (detection limit approximately 0.05 % of the tissue activity) and the distribution of LDH activity among the fractions paralleled that of pyruvate kinase, i.e. LDH was fractionated...... as a cytoplasmic enzyme. Respiratory experiments with the mitochondrial fraction also indicated the absence of LDH. Lactate did not cause respiration, nor did it affect the respiration of pyruvate + malate. The major part of the native cytochrome c was retained in the isolated mitochondria, which, furthermore...

  12. High resolution respirometry analysis of polyethylenimine-mediated mitochondrial energy crisis and cellular stress

    DEFF Research Database (Denmark)

    Hall, Arnaldur; Larsen, Anna Karina; Parhamifar, Ladan

    2013-01-01

    and spectrophotometry analysis of cytochrome c oxidase activity we were able to identify complex IV (cytochrome c oxidase) as a likely specific site of PEI mediated inhibition within the electron transport system. Unraveling the mechanisms of PEI-mediated mitochondrial energy crisis is central for combinatorial design...... of PEI-mediated plasma membrane damage and subsequent ATP leakage to the extracellular medium. Studies with freshly isolated mouse liver mitochondria corroborated with bioenergetic findings and demonstrated parallel polycation concentration- and time-dependent changes in state 2 and state 4o oxygen flux...... as well as lowered ADP phosphorylation (state 3) and mitochondrial ATP synthesis. Polycation-mediated reduction of electron transport system activity was further demonstrated in 'broken mitochondria' (freeze-thawed mitochondrial preparations). Moreover, by using both high-resolution respirometry...

  13. The effect of aging on mitochondrial proteins in germinating soybean embryonic axes

    International Nuclear Information System (INIS)

    Furman, K.C.

    1988-01-01

    Aging-induced deterioration is a major problem associated with seed storage. Impairment of mitochondrial function is one of the first effects of aging. The composition and synthesis of nuclear and mito-coded mitochondrial proteins from soybean (Glycine max. L. Merr.) embryonic axes were studied to elucidate the cause of impaired respiratory development during germination of aged seeds. Axes excised from high vigor (HV) seeds and aged or low vigor (LV) seeds were protected from imbibition injury and germinated for various times, or excised from developing seeds, and then radiolabeled for one hour in [ 35 S]methionine. Mitochondria were then isolated and total mitochondrial protein was subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), followed by quantitative staining and fluorography of labeled polypeptides. Alternatively, an original two-dimensional native-to-denaturing gel electrophoretic technique was used to analyze native protein associations and to purify a 23 kD polypeptide

  14. Repeated static contractions increase mitochondrial vulnerability toward oxidative stress in human skeletal muscle

    DEFF Research Database (Denmark)

    Sahlin, Kent; Nielsen, Jens Steen; Mogensen, Martin

    2006-01-01

    Repeated static contractions (RSC) induce large fluctuations in tissue oxygen tension and increase the generation of reactive oxygen species (ROS). This study investigated the effect of RSC on muscle contractility, mitochondrial respiratory function, and in vitro sarcoplasmic reticulum (SR) Ca(2......+) kinetics in human muscle. Ten male subjects performed five bouts of static knee extension with 10-min rest in between. Each bout of RSC (target torque 66% of maximal voluntary contraction torque) was maintained to fatigue. Muscle biopsies were taken preexercise and 0.3 and 24 h postexercise from vastus...... lateralis. Mitochondria were isolated and respiratory function measured after incubation with H(2)O(2) (HPX) or control medium (Con). Mitochondrial function was not affected by RSC during Con. However, RSC exacerbated mitochondrial dysfunction during HPX, resulting in decreased respiratory control index...

  15. ANGULAR LIGHT-SCATTERING STUDIES ON ISOLATED MITOCHONDRIA

    Science.gov (United States)

    Gotterer, Gerald S.; Thompson, Thomas E.; Lehninger, Albert L.

    1961-01-01

    Angular light-scattering studies have been carried out on suspensions of isolated rat liver mitochondria. The angular scatter pattern has a large forward component, typical of large particles. Changes in dissymmetry and in the intensity of light scattered at 90° have been correlated with changes in optical density during the course of mitochondrial swelling and contraction. Such changes can be measured at mitochondrial concentrations much below those required for optical density measurements. Changes in mitochondrial geometry caused by factors "leaking" from mitochondria, not detectable by optical density measurements, have been demonstrated by measuring changes in dissymmetry. Angular light-scattering measurements therefore offer the advantages of increased sensitivity and of added indices of changes in mitochondrial conformation. PMID:19866589

  16. Software alignment of the LHCb Outer Tracker chambers

    Energy Technology Data Exchange (ETDEWEB)

    Deissenroth, Marc

    2010-04-21

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 {mu}m) for the translational degrees of freedom and of O(10{sup -2} - 10{sup -1} mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within {proportional_to} 90 {mu}m. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  17. AN OUTER ARM IN THE SECOND GALACTIC QUADRANT: STRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xinyu; Xu, Ye; Yang, Ji; Sun, Yan; Li, Facheng; Zhang, Shaobo; Zhou, Xin, E-mail: xydu@pmo.ac.cn, E-mail: xuye@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Science, Nanjing 210008 (China)

    2016-05-01

    The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l = [100, 150]°, b = [−3, 5]° has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas—this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115 GHz {sup 12}CO(1–0) data of MWISP at the LSR velocity ≃[−100, −60] km s{sup −1} and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ∼3.1 × 10{sup 6} M {sub ⊙}. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ∼13.°1. Besides combining both the CO data from MWISP and the 21 cm H i data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.

  18. Software alignment of the LHCb Outer Tracker chambers

    International Nuclear Information System (INIS)

    Deissenroth, Marc

    2010-01-01

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 μm) for the translational degrees of freedom and of O(10 -2 - 10 -1 mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within ∝ 90 μm. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  19. Overexpression of mitochondrial sirtuins alters glycolysis and mitochondrial function in HEK293 cells.

    Directory of Open Access Journals (Sweden)

    Michelle Barbi de Moura

    Full Text Available SIRT3, SIRT4, and SIRT5 are mitochondrial deacylases that impact multiple facets of energy metabolism and mitochondrial function. SIRT3 activates several mitochondrial enzymes, SIRT4 represses its targets, and SIRT5 has been shown to both activate and repress mitochondrial enzymes. To gain insight into the relative effects of the mitochondrial sirtuins in governing mitochondrial energy metabolism, SIRT3, SIRT4, and SIRT5 overexpressing HEK293 cells were directly compared. When grown under standard cell culture conditions (25 mM glucose all three sirtuins induced increases in mitochondrial respiration, glycolysis, and glucose oxidation, but with no change in growth rate or in steady-state ATP concentration. Increased proton leak, as evidenced by oxygen consumption in the presence of oligomycin, appeared to explain much of the increase in basal oxygen utilization. Growth in 5 mM glucose normalized the elevations in basal oxygen consumption, proton leak, and glycolysis in all sirtuin over-expressing cells. While the above effects were common to all three mitochondrial sirtuins, some differences between the SIRT3, SIRT4, and SIRT5 expressing cells were noted. Only SIRT3 overexpression affected fatty acid metabolism, and only SIRT4 overexpression altered superoxide levels and mitochondrial membrane potential. We conclude that all three mitochondrial sirtuins can promote increased mitochondrial respiration and cellular metabolism. SIRT3, SIRT4, and SIRT5 appear to respond to excess glucose by inducing a coordinated increase of glycolysis and respiration, with the excess energy dissipated via proton leak.

  20. Induction of mitochondrial biogenesis and respiration is associated with mTOR regulation in hepatocytes of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA)

    Energy Technology Data Exchange (ETDEWEB)

    Hagland, Hanne R.; Nilsson, Linn I.H. [Department of Biomedicine, University of Bergen (Norway); Burri, Lena [Institute of Medicine, University of Bergen, Haukeland University Hospital (Norway); Nikolaisen, Julie [Department of Biomedicine, University of Bergen (Norway); Berge, Rolf K. [Institute of Medicine, University of Bergen, Haukeland University Hospital (Norway); Department of Heart Disease, Haukeland University Hospital (Norway); Tronstad, Karl J., E-mail: karl.tronstad@biomed.uib.no [Department of Biomedicine, University of Bergen (Norway)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer We investigated mechanisms of mitochondrial regulation in rat hepatocytes. Black-Right-Pointing-Pointer Tetradecylthioacetic acid (TTA) was employed to activate mitochondrial oxidation. Black-Right-Pointing-Pointer Mitochondrial biogenesis and respiration were induced. Black-Right-Pointing-Pointer It was confirmed that PPAR target genes were induced. Black-Right-Pointing-Pointer The mechanism involved activation mTOR. -- Abstract: The hypolipidemic effect of peroxisome proliferator-activated receptor (PPAR) activators has been explained by increasing mitochondrial fatty acid oxidation, as observed in livers of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA). PPAR-activation does, however, not fully explain the metabolic adaptations observed in hepatocytes after treatment with TTA. We therefore characterized the mitochondrial effects, and linked this to signalling by the metabolic sensor, the mammalian target of rapamycin (mTOR). In hepatocytes isolated from TTA-treated rats, the changes in cellular content and morphology were consistent with hypertrophy. This was associated with induction of multiple mitochondrial biomarkers, including mitochondrial DNA, citrate synthase and mRNAs of mitochondrial proteins. Transcription analysis further confirmed activation of PPAR{alpha}-associated genes, in addition to genes related to mitochondrial biogenesis and function. Analysis of mitochondrial respiration revealed that the capacity of both electron transport and oxidative phosphorylation were increased. These effects coincided with activation of the stress related factor, ERK1/2, and mTOR. The protein level and phosphorylation of the downstream mTOR actors eIF4G and 4E-BP1 were induced. In summary, TTA increases mitochondrial respiration by inducing hypertrophy and mitochondrial biogenesis in rat hepatocytes, via adaptive regulation of PPARs as well as mTOR.

  1. Clonality, outer-membrane proteins profile and efflux pump in KPC- producing Enterobacter sp. in Brazil.

    Science.gov (United States)

    Rosa, Juliana Ferraz; Rizek, Camila; Marchi, Ana Paula; Guimaraes, Thais; Miranda, Lourdes; Carrilho, Claudia; Levin, Anna S; Costa, Silvia F

    2017-03-17

    Carbapenems resistance in Enterobacter spp. has increased in the last decade, few studies, however, described the mechanisms of resistance in this bacterium. This study evaluated clonality and mechanisms of carbapenems resistance in clinical isolates of Enterobacter spp. identified in three hospitals in Brazil (Hospital A, B and C) over 7-year. Antibiotics sensitivity, pulsed-field gel electrophoresis (PFGE), PCR for carbapenemase and efflux pump genes were performed for all carbapenems-resistant isolates. Outer-membrane protein (OMP) was evaluated based on PFGE profile. A total of 130 isolates of Enterobacter spp were analyzed, 44/105 (41, 9%) E. aerogenes and 8/25 (32,0%) E. cloacae were resistant to carbapenems. All isolates were susceptible to fosfomycin, polymyxin B and tigecycline. KPC was present in 88.6% of E. aerogenes and in all E. cloacae resistant to carbapenems. The carbapenems-resistant E. aerogenes identified in hospital A belonged to six clones, however, a predominant clone was identified in this hospital over the study period. There is a predominant clone in Hospital B and Hospital C as well. The mechanisms of resistance to carbapenems differ among subtypes. Most of the isolates co-harbored blaKPC, blaTEM and /or blaCTX associated with decreased or lost of 35-36KDa and or 39 KDa OMP. The efflux pump AcrAB-TolC gene was only identified in carbapenems-resistant E. cloacae. There was a predominant clone in each hospital suggesting that cross-transmission of carbapenems-resistant Enterobacter spp. was frequent. The isolates presented multiple mechanisms of resistance to carbapenems including OMP alteration.

  2. Deconstructing Mitochondrial Dysfunction in Alzheimer Disease

    Directory of Open Access Journals (Sweden)

    Vega García-Escudero

    2013-01-01

    Full Text Available There is mounting evidence showing that mitochondrial damage plays an important role in Alzheimer disease. Increased oxygen species generation and deficient mitochondrial dynamic balance have been suggested to be the reason as well as the consequence of Alzheimer-related pathology. Mitochondrial damage has been related to amyloid-beta or tau pathology or to the presence of specific presenilin-1 mutations. The contribution of these factors to mitochondrial dysfunction is reviewed in this paper. Due to the relevance of mitochondrial alterations in Alzheimer disease, recent works have suggested the therapeutic potential of mitochondrial-targeted antioxidant. On the other hand, autophagy has been demonstrated to play a fundamental role in Alzheimer-related protein stress, and increasing data shows that this pathway is altered in the disease. Moreover, mitochondrial alterations have been related to an insufficient clearance of dysfunctional mitochondria by autophagy. Consequently, different approaches for the removal of damaged mitochondria or to decrease the related oxidative stress in Alzheimer disease have been described. To understand the role of mitochondrial function in Alzheimer disease it is necessary to generate human cellular models which involve living neurons. We have summarized the novel protocols for the generation of neurons by reprogramming or direct transdifferentiation, which offer useful tools to achieve this result.

  3. Mitochondrial encephalomyopathy (MELAS) with mental disorder

    International Nuclear Information System (INIS)

    Suzuki, T.; Koizumi, J.; Shiraishi, H.; Ofuku, K.; Sasaki, M.; Hori, T.; Ishikawa, N.; Anno, I.; Ohkoshi, N.

    1990-01-01

    A case of mitochondrial encephalomyopathy (MELAS) with mental disorder is reported. The SPECT study using 123 I-iodoamphetamine (IMP) and MRI study revealed abnormality in the left parieto-occipital areas without abnormality in the brain CT or brain scintigram. These findings suggest a localized dysfunction of the brain capillary endothelium in association with the cerebral involvement of mitochondrial encephalomyopathy. (orig.)

  4. Emerging Therapeutic Approaches to Mitochondrial Diseases

    Science.gov (United States)

    Wenz, Tina; Williams, Sion L.; Bacman, Sandra R.; Moraes, Carlos T.

    2010-01-01

    Mitochondrial diseases are very heterogeneous and can affect different tissues and organs. Moreover, they can be caused by genetic defects in either nuclear or mitochondrial DNA as well as by environmental factors. All of these factors have made the development of therapies difficult. In this review article, we will discuss emerging approaches to…

  5. Mitochondrial epigenetics : an overlooked layer of regulation?

    NARCIS (Netherlands)

    van der Wijst, Monique G. P.; Rots, Marianne G.

    Despite decades of research, mitochondrial epigenetics remains a controversial notion. Recent findings, however, indicate that dysfunctional mitochondrial DNA (mtDNA) methylation could underlie aging and disease. Unraveling such a level of regulation will be essential in the understanding of and in

  6. Mitochondrial dynamics in mammalian health and disease.

    Science.gov (United States)

    Liesa, Marc; Palacín, Manuel; Zorzano, Antonio

    2009-07-01

    The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.

  7. Mitochondrial dysfunction and human immunodeficiency virus ...

    African Journals Online (AJOL)

    Human immunodeficiency virus (HIV) infection and the pharmacological treatment thereof have both been shown to affect mitochondrial function in a number of tissues, and each may cause specific organ pathology through specific mitochondrial pathways. HIV has been shown to kill various tissue cells by activation of ...

  8. Mitochondrial Mutations in Subjects with Psychiatric Disorders

    NARCIS (Netherlands)

    V. Sequeira (Vasco); S.M. Rollins; C. Magnan (Christophe); M. van Oven (Mannis); P. Baldi (Pierre); R.M. Myers (Richard M.); J.D. Barchas (Jack D.); A.F. Schatzberg (Alan F); S.J. Watson (Stanley J); H. Akil (Huda); W.E. Bunney (William E.); M.P. Vawter (Marquis)

    2015-01-01

    textabstractA considerable body of evidence supports the role of mitochondrial dysfunction in psychiatric disorders and mitochondrial DNA (mtDNA) mutations are known to alter brain energy metabolism, neurotransmission, and cause neurodegenerative disorders. Genetic studies focusing on common nuclear

  9. Mitochondrial mutations and polymorphisms in psychiatric disorders

    NARCIS (Netherlands)

    V. Sequeira (Vasco); M.V. Martin (Maureen); S.M. Rollins; E.A. Moon (Emily); W.E. Bunney (William E); F. MacCiardi (Fabio); S. Lupoli (Sara); G.D. Smith; J. Kelsoe (John); C.N. Magnan (Christophe); M. van Oven (Mannis); P. Baldi (Pierre); D.C. Wallace; M.P. Vawter (Marquis)

    2012-01-01

    textabstractMitochondrial deficiencies with unknown causes have been observed in schizophrenia (SZ) and bipolar disorder (BD) in imaging and postmortem studies. Polymorphisms and somatic mutations in mitochondrial DNA (mtDNA) were investigated as potential causes with next generation sequencing of

  10. Substrate specificity within a family of outer membrane carboxylate channels.

    Directory of Open Access Journals (Sweden)

    Elif Eren

    2012-01-01

    Full Text Available Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics. In such microorganisms, the majority of small molecules are taken up by members of the OprD outer membrane protein family. Here we show that OprD channels require a carboxyl group in the substrate for efficient transport, and based on this we have renamed the family Occ, for outer membrane carboxylate channels. We further show that Occ channels can be divided into two subfamilies, based on their very different substrate specificities. Our results rationalize how certain bacteria can efficiently take up a variety of substrates under nutrient-poor conditions without compromising membrane permeability. In addition, they explain how channel inactivation in response to antibiotics can cause resistance but does not lead to decreased fitness.

  11. Knitted outer gloves in primary hip and knee arthroplasty.

    Science.gov (United States)

    Tanner, J; Wraighte, P; Howard, P

    2006-01-01

    A randomised trial was carried out to determine the rate of perforation to inner gloves when comparing latex with knitted gloves during hip and knee arthroplasty. Members of the surgical team were randomised to wear either two pairs of latex gloves (standard double gloving) or a knitted glove on top of a latex glove. In addition, participants completed a visual analogue assessment of their overall satisfaction with the gloves. A total of 406 inner gloves were tested for perforations over a four-month period: 23% of inner gloves were perforated when latex outer gloves were used and 6% of inner gloves were perforated when knitted outer gloves were used. In total, there were 64 perforations to the inner gloves; only one of these perforations was detected by the glove wearer. Wearing knitted outer gloves during hip and knee arthroplasty statistically significantly reduces the risk of perforation to inner latex gloves (p<0.0001).

  12. Outer Planet Missions with Electric Propulsion Systems—Part I

    Directory of Open Access Journals (Sweden)

    Carlos Renato Huaura Solórzano

    2010-01-01

    Full Text Available For interplanetary missions, efficient electric propulsion systems can be used to increase the mass delivered to the destination. Outer planet exploration has experienced new interest with the launch of the Cassini and New Horizons Missions. At the present, new technologies are studied for better use of electric propulsion systems in missions to the outer planets. This paper presents low-thrust trajectories using the method of the transporting trajectory to Uranus, Neptune, and Pluto. They use nuclear and radio isotopic electric propulsion. These direct transfers have continuous electric propulsion of low power along the entire trajectory. The main goal of the paper is to optimize the transfers, that is, to provide maximum mass to be delivered to the outer planets.

  13. The outer magnetosphere. [composition and comparison with earth

    Science.gov (United States)

    Schardt, A. W.; Behannon, K. W.; Lepping, R. P.; Carbary, J. F.; Eviatar, A.; Siscoe, G. L.

    1984-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  14. Mitochondrial NUDIX hydrolases: A metabolic link between NAD catabolism, GTP and mitochondrial dynamics.

    Science.gov (United States)

    Long, Aaron; Klimova, Nina; Kristian, Tibor

    2017-10-01

    NAD + catabolism and mitochondrial dynamics are important parts of normal mitochondrial function and are both reported to be disrupted in aging, neurodegenerative diseases, and acute brain injury. While both processes have been extensively studied there has been little reported on how the mechanisms of these two processes are linked. This review focuses on how downstream NAD + catabolism via NUDIX hydrolases affects mitochondrial dynamics under pathologic conditions. Additionally, several potential targets in mitochondrial dysfunction and fragmentation are discussed, including the roles of mitochondrial poly(ADP-ribose) polymerase 1(mtPARP1), AMPK, AMP, and intra-mitochondrial GTP metabolism. Mitochondrial and cytosolic NUDIX hydrolases (NUDT9α and NUDT9β) can affect mitochondrial and cellular AMP levels by hydrolyzing ADP- ribose (ADPr) and subsequently altering the levels of GTP and ATP. Poly (ADP-ribose) polymerase 1 (PARP1) is activated after DNA damage, which depletes NAD + pools and results in the PARylation of nuclear and mitochondrial proteins. In the mitochondria, ADP-ribosyl hydrolase-3 (ARH3) hydrolyzes PAR to ADPr, while NUDT9α metabolizes ADPr to AMP. Elevated AMP levels have been reported to reduce mitochondrial ATP production by inhibiting the adenine nucleotide translocase (ANT), allosterically activating AMPK by altering the cellular AMP: ATP ratio, and by depleting mitochondrial GTP pools by being phosphorylated by adenylate kinase 3 (AK3), which uses GTP as a phosphate donor. Recently, activated AMPK was reported to phosphorylate mitochondria fission factor (MFF), which increases Drp1 localization to the mitochondria and promotes mitochondrial fission. Moreover, the increased AK3 activity could deplete mitochondrial GTP pools and possibly inhibit normal activity of GTP-dependent fusion enzymes, thus altering mitochondrial dynamics. Published by Elsevier Ltd.

  15. Loss of Mitochondrial Function Impairs Lysosomes.

    Science.gov (United States)

    Demers-Lamarche, Julie; Guillebaud, Gérald; Tlili, Mouna; Todkar, Kiran; Bélanger, Noémie; Grondin, Martine; Nguyen, Angela P; Michel, Jennifer; Germain, Marc

    2016-05-06

    Alterations in mitochondrial function, as observed in neurodegenerative diseases, lead to disrupted energy metabolism and production of damaging reactive oxygen species. Here, we demonstrate that mitochondrial dysfunction also disrupts the structure and function of lysosomes, the main degradation and recycling organelle. Specifically, inhibition of mitochondrial function, following deletion of the mitochondrial protein AIF, OPA1, or PINK1, as well as chemical inhibition of the electron transport chain, impaired lysosomal activity and caused the appearance of large lysosomal vacuoles. Importantly, our results show that lysosomal impairment is dependent on reactive oxygen species. Given that alterations in both mitochondrial function and lysosomal activity are key features of neurodegenerative diseases, this work provides important insights into the etiology of neurodegenerative diseases. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. The 2-oxoglutarate carrier promotes liver cancer by sustaining mitochondrial GSH despite cholesterol loading

    Directory of Open Access Journals (Sweden)

    Anna Baulies

    2018-04-01

    Full Text Available Cancer cells exhibit mitochondrial cholesterol (mt-cholesterol accumulation, which contributes to cell death resistance by antagonizing mitochondrial outer membrane (MOM permeabilization. Hepatocellular mt-cholesterol loading, however, promotes steatohepatitis, an advanced stage of chronic liver disease that precedes hepatocellular carcinoma (HCC, by depleting mitochondrial GSH (mGSH due to a cholesterol-mediated impairment in mGSH transport. Whether and how HCC cells overcome the restriction of mGSH transport imposed by mt-cholesterol loading to support mGSH uptake remains unknown. Although the transport of mGSH is not fully understood, SLC25A10 (dicarboxylate carrier, DIC and SLC25A11 (2-oxoglutarate carrier, OGC have been involved in mGSH transport, and therefore we examined their expression and role in HCC. Unexpectedly, HCC cells and liver explants from patients with HCC exhibit divergent expression of these mitochondrial carriers, with selective OGC upregulation, which contributes to mGSH maintenance. OGC but not DIC downregulation by siRNA depleted mGSH levels and sensitized HCC cells to hypoxia-induced ROS generation and cell death as well as impaired cell growth in three-dimensional multicellular HCC spheroids, effects that were reversible upon mGSH replenishment by GSH ethyl ester, a membrane permeable GSH precursor. We also show that OGC regulates mitochondrial respiration and glycolysis. Moreover, OGC silencing promoted hypoxia-induced cardiolipin peroxidation, which reversed the inhibition of cholesterol on the permeabilization of MOM-like liposomes induced by Bax or Bak. Genetic OGC knockdown reduced the ability of tumor-initiating stem-like cells to induce liver cancer. These findings underscore the selective overexpression of OGC as an adaptive mechanism of HCC to provide adequate mGSH levels in the face of mt-cholesterol loading and suggest that OGC may be a novel therapeutic target for HCC treatment. Keywords: Cholesterol

  17. Activation-dependent mitochondrial translocation of Foxp3 in human hepatocytes

    International Nuclear Information System (INIS)

    Rojas, Joselyn; Teran-Angel, Guillermo; Barbosa, Luisa; Peterson, Darrell L.; Berrueta, Lisbeth; Salmen, Siham

    2016-01-01

    Foxp3 is considered to be the master regulator for the development and function of regulatory T cells (Treg). Recently Foxp3, has been detected in extra lymphoid tissue, and in hepatocytes and has been associated with hepatocellular carcinoma (HCC), although its role has not been defined. Since it is expected that there is a relationship between protein localization, activity and cellular function, the aim of this study was to explore the subcellular localization of Foxp3 in resting and stimulated human hepatocytes. Foxp3 expression was measured by flow cytometry, subcellular fractioning, and immunofluorescence, and this data was used to track the shuttling of Foxp3 in different subcellular compartments in hepatocytes (HepG2 cell line), stimulated by using the PKC activators (PMA), core and preS1/2 antigen from hepatitis B virus (HBV). Our data shows that besides the nuclear location, mitochondrial translocation was detected after stimulation with PMA and at to a lesser extent, with preS1/2. In addition, Foxp3 is localizes at outer mitochondrial membrane. These results suggest a non-canonical role of Foxp3 in the mitochondrial compartment in human hepatocytes, and opens a new field about their role in liver damages during HBV infection. - Highlights: • The expression and subcellular distribution of Foxp3, is modulated by PMA and preS1/2. • PMA and preS1/2 increase Foxp3 expression on HepG2. • PMA and preS1/2 induce foxp3 enrichment at mitochondrial, microsomal and nuclear compartments. • Results suggest a non-canonical function of Foxp3 or a mitochondrial transcriptional activity.

  18. Activation-dependent mitochondrial translocation of Foxp3 in human hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, Joselyn; Teran-Angel, Guillermo; Barbosa, Luisa [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Peterson, Darrell L. [Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA (United States); Berrueta, Lisbeth, E-mail: lberruet@ula.ve [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Division of Preventive Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Salmen, Siham, E-mail: sihamsa@ula.ve [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of)

    2016-05-01

    Foxp3 is considered to be the master regulator for the development and function of regulatory T cells (Treg). Recently Foxp3, has been detected in extra lymphoid tissue, and in hepatocytes and has been associated with hepatocellular carcinoma (HCC), although its role has not been defined. Since it is expected that there is a relationship between protein localization, activity and cellular function, the aim of this study was to explore the subcellular localization of Foxp3 in resting and stimulated human hepatocytes. Foxp3 expression was measured by flow cytometry, subcellular fractioning, and immunofluorescence, and this data was used to track the shuttling of Foxp3 in different subcellular compartments in hepatocytes (HepG2 cell line), stimulated by using the PKC activators (PMA), core and preS1/2 antigen from hepatitis B virus (HBV). Our data shows that besides the nuclear location, mitochondrial translocation was detected after stimulation with PMA and at to a lesser extent, with preS1/2. In addition, Foxp3 is localizes at outer mitochondrial membrane. These results suggest a non-canonical role of Foxp3 in the mitochondrial compartment in human hepatocytes, and opens a new field about their role in liver damages during HBV infection. - Highlights: • The expression and subcellular distribution of Foxp3, is modulated by PMA and preS1/2. • PMA and preS1/2 increase Foxp3 expression on HepG2. • PMA and preS1/2 induce foxp3 enrichment at mitochondrial, microsomal and nuclear compartments. • Results suggest a non-canonical function of Foxp3 or a mitochondrial transcriptional activity.

  19. Induced mitochondrial membrane potential for modeling solitonic conduction of electrotonic signals.

    Directory of Open Access Journals (Sweden)

    R R Poznanski

    Full Text Available A cable model that includes polarization-induced capacitive current is derived for modeling the solitonic conduction of electrotonic potentials in neuronal branchlets with microstructure containing endoplasmic membranes. A solution of the nonlinear cable equation modified for fissured intracellular medium with a source term representing charge 'soakage' is used to show how intracellular capacitive effects of bound electrical charges within mitochondrial membranes can influence electrotonic signals expressed as solitary waves. The elastic collision resulting from a head-on collision of two solitary waves results in localized and non-dispersing electrical solitons created by the nonlinearity of the source term. It has been shown that solitons in neurons with mitochondrial membrane and quasi-electrostatic interactions of charges held by the microstructure (i.e., charge 'soakage' have a slower velocity of propagation compared with solitons in neurons with microstructure, but without endoplasmic membranes. When the equilibrium potential is a small deviation from rest, the nonohmic conductance acts as a leaky channel and the solitons are small compared when the equilibrium potential is large and the outer mitochondrial membrane acts as an amplifier, boosting the amplitude of the endogenously generated solitons. These findings demonstrate a functional role of quasi-electrostatic interactions of bound electrical charges held by microstructure for sustaining solitons with robust self-regulation in their amplitude through changes in the mitochondrial membrane equilibrium potential. The implication of our results indicate that a phenomenological description of ionic current can be successfully modeled with displacement current in Maxwell's equations as a conduction process involving quasi-electrostatic interactions without the inclusion of diffusive current. This is the first study in which solitonic conduction of electrotonic potentials are generated by

  20. A novel fission-independent role of dynamin-related protein 1 in cardiac mitochondrial respiration.

    Science.gov (United States)

    Zhang, Huiliang; Wang, Pei; Bisetto, Sara; Yoon, Yisang; Chen, Quan; Sheu, Shey-Shing; Wang, Wang

    2017-02-01

    Mitochondria in adult cardiomyocytes exhibit static morphology and infrequent dynamic changes, despite the high abundance of fission and fusion regulatory proteins in the heart. Previous reports have indicated that fusion proteins may bear functions beyond morphology regulation. Here, we investigated the role of fission protein, dynamin-related protein 1 (DRP1), on mitochondrial respiration regulation in adult cardiomyocytes. By using genetic or pharmacological approaches, we manipulated the activity or protein level of fission and fusion proteins and found they mildly influenced mitochondrial morphology in adult rodent cardiomyocytes, which is in contrast to their significant effect in H9C2 cardiac myoblasts. Intriguingly, inhibiting endogenous DRP1 by dominant-negative DRP1 mutation (K38A), shRNA, or Mdivi-1 suppressed maximal respiration and respiratory control ratio in isolated mitochondria from adult mouse heart or in adult cardiomyocytes from rat. Meanwhile, basal respiration was increased due to increased proton leak. Facilitating mitofusin-mediated fusion by S3 compound, however, failed to inhibit mitochondrial respiration in adult cardiomyocytes. Mechanistically, DRP1 inhibition did not affect the maximal activity of individual respiratory chain complexes or the assembly of supercomplexes. Knocking out cyclophilin D, a regulator of mitochondrial permeability transition pore (mPTP), abolished the effect of DRP1 inhibition on respiration. Finally, DRP1 inhibition decreased transient mPTP-mediated mitochondrial flashes, delayed laser-induced mPTP opening and suppressed mitochondrial reactive oxygen species (ROS). These results uncover a novel non-canonical function of the fission protein, DRP1 in maintaining or positively stimulating mitochondrial respiration, bioenergetics and ROS signalling in adult cardiomyocyte, which is likely independent of morphological changes. Published on behalf of the European Society of Cardiology. All rights reserved. © The

  1. Culture creates genetic structure in the Caucasus: Autosomal, mitochondrial, and Y-chromosomal variation in Daghestan

    Directory of Open Access Journals (Sweden)

    Harpending Henry C

    2008-07-01

    Full Text Available Abstract Background Near the junction of three major continents, the Caucasus region has been an important thoroughfare for human migration. While the Caucasus Mountains have diverted human traffic to the few lowland regions that provide a gateway from north to south between the Caspian and Black Seas, highland populations have been isolated by their remote geographic location and their practice of patrilocal endogamy. We investigate how these cultural and historical differences between highland and lowland populations have affected patterns of genetic diversity. We test 1 whether the highland practice of patrilocal endogamy has generated sex-specific population relationships, and 2 whether the history of migration and military conquest associated with the lowland populations has left Central Asian genes in the Caucasus, by comparing genetic diversity and pairwise population relationships between Daghestani populations and reference populations throughout Europe and Asia for autosomal, mitochondrial, and Y-chromosomal markers. Results We found that the highland Daghestani populations had contrasting histories for the mitochondrial DNA and Y-chromosome data sets. Y-chromosomal haplogroup diversity was reduced among highland Daghestani populations when compared to other populations and to highland Daghestani mitochondrial DNA haplogroup diversity. Lowland Daghestani populations showed Turkish and Central Asian affinities for both mitochondrial and Y-chromosomal data sets. Autosomal population histories are strongly correlated to the pattern observed for the mitochondrial DNA data set, while the correlation between the mitochondrial DNA and Y-chromosome distance matrices was weak and not significant. Conclusion The reduced Y-chromosomal diversity exhibited by highland Daghestani populations is consistent with genetic drift caused by patrilocal endogamy. Mitochondrial and Y-chromosomal phylogeographic comparisons indicate a common Near Eastern

  2. Mitochondrial Genomes of Kinorhyncha: trnM Duplication and New Gene Orders within Animals.

    Science.gov (United States)

    Popova, Olga V; Mikhailov, Kirill V; Nikitin, Mikhail A; Logacheva, Maria D; Penin, Aleksey A; Muntyan, Maria S; Kedrova, Olga S; Petrov, Nikolai B; Panchin, Yuri V; Aleoshin, Vladimir V

    2016-01-01

    Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha-an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the early-branching lineages of Ecdysozoa, and their mitochondrial genomes may be important for resolving evolutionary relations between major animal taxa. Here we present the results of sequencing and analysis of mitochondrial genomes from two members of Kinorhyncha, Echinoderes svetlanae (Cyclorhagida) and Pycnophyes kielensis (Allomalorhagida). Their mitochondrial genomes are circular molecules approximately 15 Kbp in size. The kinorhynch mitochondrial gene sequences are highly divergent, which precludes accurate phylogenetic inference. The mitogenomes of both species encode a typical metazoan complement of 37 genes, which are all positioned on the major strand, but the gene order is distinct and unique among Ecdysozoa or animals as a whole. We predict four types of start codons for protein-coding genes in E. svetlanae and five in P. kielensis with a consensus DTD in single letter code. The mitochondrial genomes of E. svetlanae and P. kielensis encode duplicated methionine tRNA genes that display compensatory nucleotide substitutions. Two distant species of Kinorhyncha demonstrate similar patterns of gene arrangements in their mitogenomes. Both genomes have duplicated methionine tRNA genes; the duplication predates the divergence of two species. The kinorhynchs share a few features pertaining to gene order that align them with Priapulida. Gene order analysis reveals that gene arrangement specific of Priapulida may be ancestral for Scalidophora, Ecdysozoa, and even Protostomia.

  3. Mitochondrial Genomes of Kinorhyncha: trnM Duplication and New Gene Orders within Animals.

    Directory of Open Access Journals (Sweden)

    Olga V Popova

    Full Text Available Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha-an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the early-branching lineages of Ecdysozoa, and their mitochondrial genomes may be important for resolving evolutionary relations between major animal taxa. Here we present the results of sequencing and analysis of mitochondrial genomes from two members of Kinorhyncha, Echinoderes svetlanae (Cyclorhagida and Pycnophyes kielensis (Allomalorhagida. Their mitochondrial genomes are circular molecules approximately 15 Kbp in size. The kinorhynch mitochondrial gene sequences are highly divergent, which precludes accurate phylogenetic inference. The mitogenomes of both species encode a typical metazoan complement of 37 genes, which are all positioned on the major strand, but the gene order is distinct and unique among Ecdysozoa or animals as a whole. We predict four types of start codons for protein-coding genes in E. svetlanae and five in P. kielensis with a consensus DTD in single letter code. The mitochondrial genomes of E. svetlanae and P. kielensis encode duplicated methionine tRNA genes that display compensatory nucleotide substitutions. Two distant species of Kinorhyncha demonstrate similar patterns of gene arrangements in their mitogenomes. Both genomes have duplicated methionine tRNA genes; the duplication predates the divergence of two species. The kinorhynchs share a few features pertaining to gene order that align them with Priapulida. Gene order analysis reveals that gene arrangement specific of Priapulida may be ancestral for Scalidophora, Ecdysozoa, and even

  4. Sleep disorders associated with primary mitochondrial diseases.

    Science.gov (United States)

    Ramezani, Ryan J; Stacpoole, Peter W

    2014-11-15

    Primary mitochondrial diseases are caused by heritable or spontaneous mutations in nuclear DNA or mitochondrial DNA. Such pathological mutations are relatively common in humans and may lead to neurological and neuromuscular complication that could compromise normal sleep behavior. To gain insight into the potential impact of primary mitochondrial disease and sleep pathology, we reviewed the relevant English language literature in which abnormal sleep was reported in association with a mitochondrial disease. We examined publication reported in Web of Science and PubMed from February 1976 through January 2014, and identified 54 patients with a proven or suspected primary mitochondrial disorder who were evaluated for sleep disturbances. Both nuclear DNA and mitochondrial DNA mutations were associated with abnormal sleep patterns. Most subjects who underwent polysomnography had central sleep apnea, and only 5 patients had obstructive sleep apnea. Twenty-four patients showed decreased ventilatory drive in response to hypoxia and/ or hyperapnea that was not considered due to weakness of the intrinsic muscles of respiration. Sleep pathology may be an underreported complication of primary mitochondrial diseases. The probable underlying mechanism is cellular energy failure causing both central neurological and peripheral neuromuscular degenerative changes that commonly present as central sleep apnea and poor ventilatory response to hyperapnea. Increased recognition of the genetics and clinical manifestations of mitochondrial diseases by sleep researchers and clinicians is important in the evaluation and treatment of all patients with sleep disturbances. Prospective population-based studies are required to determine the true prevalence of mitochondrial energy failure in subjects with sleep disorders, and conversely, of individuals with primary mitochondrial diseases and sleep pathology. © 2014 American Academy of Sleep Medicine.

  5. Study of Power Options for Jupiter and Outer Planet Missions

    Science.gov (United States)

    Landis, Geoffrey A.; Fincannon, James

    2015-01-01

    Power for missions to Jupiter and beyond presents a challenging goal for photovoltaic power systems, but NASA missions including Juno and the upcoming Europa Clipper mission have shown that it is possible to operate solar arrays at Jupiter. This work analyzes photovoltaic technologies for use in Jupiter and outer planet missions, including both conventional arrays, as well as analyzing the advantages of advanced solar cells, concentrator arrays, and thin film technologies. Index Terms - space exploration, spacecraft solar arrays, solar electric propulsion, photovoltaic cells, concentrator, Fresnel lens, Jupiter missions, outer planets.

  6. Colors of Outer Solar System Objects Measured with VATT

    Science.gov (United States)

    Romanishin, William; Tegler, S. C.; Consolmagno, G. J.

    2010-10-01

    Over the past 7 years, we have measured optical B-V and V-R colors for about 40 minor outer solar system objects using the 1.8-m Vatican Advanced Technology Telescope (VATT) located on Mt. Graham in southeast Arizona. We will present these colors and use them to update the discussion of colors of minor bodies in the outer solar system. We gratefully acknowledge funding from the NASA Planetary Astronomy Program to Northern Arizona University and the U. of Oklahoma which helped support this work.

  7. Photoprotective substance occurs primarily in outer layers of fish skin.

    Science.gov (United States)

    Fabacher, D L; Little, E E

    1998-01-01

    Methanol extracts of dorsal skin layers, eyes, gills, and livers from ultraviolet-B (UVB) radiation-sensitive and UVB-tolerant species of freshwater fish were examined for a substance that appears to be photoprotective. Significantly larger amounts of this substance were found in extracts of outer dorsal skin layers from both UVB-sensitive and UVB-tolerant fish when compared with extracts of inner dorsal skin layers. This substance occurred in minor amounts or was not detected in eye, gill, and liver extracts. The apparent primary function of this substance in fish is to protect the cells in outer dorsal skin layers from harmful levels of UVB radiation.

  8. Stability of marginally outer trapped surfaces and symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, Alberto; Mars, Marc, E-mail: acf@usal.e, E-mail: marc@usal.e [Facultad de Ciencias, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain)

    2009-09-07

    We study the properties of stable, strictly stable and locally outermost marginally outer trapped surfaces in spacelike hypersurfaces of spacetimes possessing certain symmetries such as isometries, homotheties and conformal Killings. We first obtain results for general diffeomorphisms in terms of the so-called metric deformation tensor and then particularize to different types of symmetries. In particular, we find restrictions at the surfaces on the vector field generating the symmetry. Some consequences are discussed. As an application, we present a result on non-existence of stable marginally outer trapped surfaces in slices of FLRW.

  9. Hypoxia-induced decrease of UCP3 gene expression in rat heart parallels metabolic gene switching but fails to affect mitochondrial respiratory coupling.

    Science.gov (United States)

    Essop, M Faadiel; Razeghi, Peter; McLeod, Chris; Young, Martin E; Taegtmeyer, Heinrich; Sack, Michael N

    2004-02-06

    Mitochondrial uncoupling proteins 2 and 3 (UCP2 and UCP3) are postulated to contribute to antioxidant defense, nutrient partitioning, and energy efficiency in the heart. To distinguish isotype function in response to metabolic stress we measured cardiac mitochondrial function and cardiac UCP gene expression following chronic hypobaric hypoxia. Isolated mitochondrial O(2) consumption and ATP synthesis rate were reduced but respiratory coupling was unchanged compared to normoxic groups. Concurrently, left ventricular UCP3 mRNA levels were significantly decreased with hypoxia (pheart as opposed to uncoupling of mitochondria. Moreover, the divergent hypoxia-induced regulation of UCP2 and UCP3 supports distinct mitochondrial regulatory functions of these inner mitochondrial membrane proteins in the heart in response to metabolic stress.

  10. Nrf2 impacts cellular bioenergetics by controlling substrate availability for mitochondrial respiration

    Directory of Open Access Journals (Sweden)

    Kira M. Holmström

    2013-06-01

    Transcription factor Nrf2 and its repressor Keap1 regulate a network of cytoprotective genes involving more than 1% of the genome, their best known targets being drug-metabolizing and antioxidant genes. Here we demonstrate a novel role for this pathway in directly regulating mitochondrial bioenergetics in murine neurons and embryonic fibroblasts. Loss of Nrf2 leads to mitochondrial depolarisation, decreased ATP levels and impaired respiration, whereas genetic activation of Nrf2 increases the mitochondrial membrane potential and ATP levels, the rate of respiration and the efficiency of oxidative phosphorylation. We further show that Nrf2-deficient cells have increased production of ATP in glycolysis, which is then used by the F1Fo-ATPase for maintenance of the mitochondrial membrane potential. While the levels and in vitro activities of the respiratory complexes are unaffected by Nrf2 deletion, their activities in isolated mitochondria and intact live cells are substantially impaired. In addition, the rate of regeneration of NADH after inhibition of respiration is much slower in Nrf2-knockout cells than in their wild-type counterparts. Taken together, these results show that Nrf2 directly regulates cellular energy metabolism through modulating the availability of substrates for mitochondrial respiration. Our findings highlight the importance of efficient energy metabolism in Nrf2-mediated cytoprotection.

  11. Renal Oxidative Stress Induced by Long-Term Hyperuricemia Alters Mitochondrial Function and Maintains Systemic Hypertension

    Directory of Open Access Journals (Sweden)

    Magdalena Cristóbal-García

    2015-01-01

    Full Text Available We addressed if oxidative stress in the renal cortex plays a role in the induction of hypertension and mitochondrial alterations in hyperuricemia. A second objective was to evaluate whether the long-term treatment with the antioxidant Tempol prevents renal oxidative stress, mitochondrial alterations, and systemic hypertension in this model. Long-term (11-12 weeks and short-term (3 weeks effects of oxonic acid induced hyperuricemia were studied in rats (OA, 750 mg/kg BW, OA+Allopurinol (AP, 150 mg/L drinking water, OA+Tempol (T, 15 mg/kg BW, or vehicle. Systolic blood pressure, renal blood flow, and vascular resistance were measured. Tubular damage (urine N-acetyl-β-D-glucosaminidase and oxidative stress markers (lipid and protein oxidation along with ATP levels were determined in kidney tissue. Oxygen consumption, aconitase activity, and uric acid were evaluated in isolated mitochondria from renal cortex. Short-term hyperuricemia resulted in hypertension without demonstrable renal oxidative stress or mitochondrial dysfunction. Long-term hyperuricemia induced hypertension, renal vasoconstriction, tubular damage, renal cortex oxidative stress, and mitochondrial dysfunction and decreased ATP levels. Treatments with Tempol and allopurinol prevented these alterations. Renal oxidative stress induced by hyperuricemia promoted mitochondrial functional disturbances and decreased ATP content, which represent an additional pathogenic mechanism induced by chronic hyperuricemia. Hyperuricemia-related hypertension occurs before these changes are evident.

  12. Adipose tissue mitochondrial dysfunction triggers a lipodystrophic syndrome with insulin resistance, hepatosteatosis, and cardiovascular complications.

    Science.gov (United States)

    Vernochet, Cecile; Damilano, Federico; Mourier, Arnaud; Bezy, Olivier; Mori, Marcelo A; Smyth, Graham; Rosenzweig, Anthony; Larsson, Nils-Göran; Kahn, C Ronald

    2014-10-01

    Mitochondrial dysfunction in adipose tissue occurs in obesity, type 2 diabetes, and some forms of lipodystrophy, but whether this dysfunction contributes to or is the result of these disorders is unknown. To investigate the physiological consequences of severe mitochondrial impairment in adipose tissue, we generated mice deficient in mitochondrial transcription factor A (TFAM) in adipocytes by using mice carrying adiponectin-Cre and TFAM floxed alleles. These adiponectin TFAM-knockout (adipo-TFAM-KO) mice had a 75-81% reduction in TFAM in the subcutaneous and intra-abdominal white adipose tissue (WAT) and interscapular brown adipose tissue (BAT), causing decreased expression and enzymatic activity of proteins in complexes I, III, and IV of the electron transport chain (ETC). This mitochondrial dysfunction led to adipocyte death and inflammation in WAT and a whitening of BAT. As a result, adipo-TFAM-KO mice were resistant to weight gain, but exhibited insulin resistance on both normal chow and high-fat diets. These lipodystrophic mice also developed hypertension, cardiac hypertrophy, and cardiac dysfunction. Thus, isolated mitochondrial dysfunction in adipose tissue can lead a syndrome of lipodystrophy with metabolic syndrome and cardiovascular complications. © FASEB.

  13. Apricot melanoidins prevent oxidative endothelial cell death by counteracting mitochondrial oxidation and membrane depolarization.

    Directory of Open Access Journals (Sweden)

    Annalisa Cossu

    Full Text Available The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs is the key step for the onset and progression of cardiovascular diseases (CVD, therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP, while the mitochondrial membrane potential (MMP was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial