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Sample records for mitochondria occurs independently

  1. In vivo imaging reveals mitophagy independence in the maintenance of axonal mitochondria during normal aging.

    Science.gov (United States)

    Cao, Xu; Wang, Haiqiong; Wang, Zhao; Wang, Qingyao; Zhang, Shuang; Deng, Yuanping; Fang, Yanshan

    2017-10-01

    Mitophagy is thought to be a critical mitochondrial quality control mechanism in neurons and has been extensively studied in neurological disorders such as Parkinson's disease. However, little is known about how mitochondria are maintained in the lengthy neuronal axons in the context of physiological aging. Here, we utilized the unique Drosophila wing nerve model and in vivo imaging to rigorously profile changes in axonal mitochondria during aging. We revealed that mitochondria became fragmented and accumulated in aged axons. However, lack of Pink1 or Parkin did not lead to the accumulation of axonal mitochondria or axonal degeneration. Further, unlike in in vitro cultured neurons, we found that mitophagy rarely occurred in intact axons in vivo, even in aged animals. Furthermore, blocking overall mitophagy by knockdown of the core autophagy genes Atg12 or Atg17 had little effect on the turnover of axonal mitochondria or axonal integrity, suggesting that mitophagy is not required for axonal maintenance; this is regardless of whether the mitophagy is PINK1-Parkin dependent or independent. In contrast, downregulation of mitochondrial fission-fusion genes caused age-dependent axonal degeneration. Moreover, Opa1 expression in the fly head was significantly decreased with age, which may underlie the accumulation of fragmented mitochondria in aged axons. Finally, we showed that adult-onset, neuronal downregulation of the fission-fusion, but not mitophagy genes, dramatically accelerated features of aging. We propose that axonal mitochondria are maintained independently of mitophagy and that mitophagy-independent mechanisms such as fission-fusion may be central to the maintenance of axonal mitochondria and neural integrity during normal aging. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  2. Pifithrin-α provides neuroprotective effects at the level of mitochondria independently of p53 inhibition.

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    Neitemeier, Sandra; Ganjam, Goutham K; Diemert, Sebastian; Culmsee, Carsten

    2014-12-01

    Impaired mitochondrial integrity and function are key features of intrinsic death pathways in neuronal cells. Therefore, key regulators of intrinsic death pathways acting upstream of mitochondria are potential targets for therapeutic approaches of neuroprotection. The tumor suppressor p53 is a well-established regulator of cellular responses towards different kinds of lethal stress, including oxidative stress. Recent reports suggested that p53 may affect mitochondrial integrity and function through both, transcriptional activation of mitochondria-targeted pro-death proteins and direct effects at the mitochondrial membrane. In the present study, we compared the effects of pharmacological inhibition of p53 by pifithrin-α with those of selective p53 gene silencing by RNA interference. Using MTT assay and real-time cell impedance measurements we confirmed the protective effect of both strategies against glutamate-induced oxidative stress in immortalized mouse hippocampal HT-22 neurons. Further, we observed full restoration of mitochondrial membrane potential and inhibition of glutamate-induced mitochondrial fragmentation by pifithrin-α which was, in contrast, not achieved by p53 gene silencing. Downregulation of p53 by siRNA decreased p53 transcriptional activity and reduced expression levels of p21 mRNA, while pifithrin-α did not affect these endpoints. These results suggest a neuroprotective effect of pifithrin-α which occurred at the level of mitochondria and independently of p53 inhibition.

  3. [Oxidative power and intracellular distribution of mitochondria control cell oxygen regime when arterial hypoxemia occurs].

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    Liabakh, E G; Lissov, P N

    2012-01-01

    The regulatory impact of the mitochondria spatial distribution and enlargement in their oxidative power qO2 on the tissue oxygenation of skeletal muscle during hypoxia were studied. Investigations were performed by the mathematical modeling of 3D O2 diffusion-reaction in muscle fiber. The oxygen consumption rate VO2 and tissue pO2 were analyzed in response to a decrease in arterial blood oxygen concentration from 19.5 to 10 vol. % at a moderate load (3.5 ml/min per 100 g). The cells with evenly (case 1) and unevenly (case 2) distributed mitochondria were considered. According to calculations due to a rise in mitochondria oxidative power from 3.5 to 6.5 ml/min. per 100 g of tissue it is possible to maintain muscle oxygen V(O2) at constant level of 3.5 ml/min per 100 g despite a decrease in O2 delivery. Minimum value of tissue pO2 was about 0 and an area of hypoxia appeared inside the cell in case 1. But hypoxia disappeared and minimum value of pO2 increased from 0 to 4 mm Hg if mitochondria were distributed unevenly (case 2). It is shown that the possibilities of such regulation were limited and depended on the ratio of "the degree of hypoxemia--the level of oxygen delivery." It was assumed that an increase in mitochondria enzyme activity and mitochondria migration to the places of the greatest oxygen consumption rate can improve oxygen regime in the cells in terms of their adaptation to hypoxia. It is possible that changes in mitochondrial oxidative power and their intracellular redistribution may be considered as a new dimension in regulation of cell oxygen regime.

  4. Telomere-independent functions of telomerase in nuclei, cytoplasm, and mitochondria

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    Chiodi, Ilaria; Mondello, Chiara, E-mail: mondello@igm.cnr.it [Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia (Italy)

    2012-09-28

    Telomerase canonical activity at telomeres prevents telomere shortening, allowing chromosome stability and cellular proliferation. To perform this task, the catalytic subunit (telomerase reverse transcriptase, TERT) of the enzyme works as a reverse transcriptase together with the telomerase RNA component (TERC), adding telomeric repeats to DNA molecule ends. Growing evidence indicates that, besides the telomeric-DNA synthesis activity, TERT has additional functions in tumor development and is involved in many different biological processes, among which cellular proliferation, gene expression regulation, and mitochondrial functionality. TERT has been shown to act independently of TERC in the Wnt-β-catenin signaling pathway, regulating the expression of Wnt target genes, which play a role in development and tumorigenesis. Moreover, TERT RNA-dependent RNA polymerase activity has been found, leading to the genesis of double-stranded RNAs that act as precursor of silencing RNAs. In mitochondria, a TERT TERC-independent reverse transcriptase activity has been described that could play a role in the protection of mitochondrial integrity. In this review, we will discuss some of the extra-telomeric functions of telomerase.

  5. Differential protection by wildtype vs. organelle-specific Bcl-2 suggests a combined requirement of both the ER and mitochondria in ceramide-mediated caspase-independent programmed cell death

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    Belka Claus

    2009-10-01

    Full Text Available Abstract Background Programmed cell death (PCD is essential for development and homeostasis of multicellular organisms and can occur by caspase-dependent apoptosis or alternatively, by caspase-independent PCD (ciPCD. Bcl-2, a central regulator of apoptosis, localizes to both mitochondria and the endoplasmic reticulum (ER. Whereas a function of mitochondrial and ER-specific Bcl-2 in apoptosis has been established in multiple studies, corresponding data for ciPCD do not exist. Methods We utilized Bcl-2 constructs specifically localizing to mitochondria (Bcl-2 ActA, the ER (Bcl-2 cb5, both (Bcl-2 WT or the cytosol/nucleus (Bcl-2 ΔTM and determined their protective effect on ceramide-mediated ciPCD in transiently and stably transfected Jurkat cells. Expression of the constructs was verified by immunoblots. Ceramide-mediated ciPCD was induced by treatment with human recombinant tumor necrosis factor and determined by flow cytometric measurement of propidium iodide uptake as well as by optical analysis of cell morphology. Results Only wildtype Bcl-2 had the ability to efficiently protect from ceramide-mediated ciPCD, whereas expression of Bcl-2 solely at mitochondria, the ER, or the cytosol/nucleus did not prevent ceramide-mediated ciPCD. Conclusion Our data suggest a combined requirement for both mitochondria and the ER in the induction and the signaling pathways of ciPCD mediated by ceramide.

  6. Differential protection by wildtype vs. organelle-specific Bcl-2 suggests a combined requirement of both the ER and mitochondria in ceramide-mediated caspase-independent programmed cell death

    International Nuclear Information System (INIS)

    Deerberg, Andrea; Sosna, Justyna; Thon, Lutz; Belka, Claus; Adam, Dieter

    2009-01-01

    Programmed cell death (PCD) is essential for development and homeostasis of multicellular organisms and can occur by caspase-dependent apoptosis or alternatively, by caspase-independent PCD (ciPCD). Bcl-2, a central regulator of apoptosis, localizes to both mitochondria and the endoplasmic reticulum (ER). Whereas a function of mitochondrial and ER-specific Bcl-2 in apoptosis has been established in multiple studies, corresponding data for ciPCD do not exist. We utilized Bcl-2 constructs specifically localizing to mitochondria (Bcl-2 ActA), the ER (Bcl-2 cb5), both (Bcl-2 WT) or the cytosol/nucleus (Bcl-2 ΔTM) and determined their protective effect on ceramide-mediated ciPCD in transiently and stably transfected Jurkat cells. Expression of the constructs was verified by immunoblots. Ceramide-mediated ciPCD was induced by treatment with human recombinant tumor necrosis factor and determined by flow cytometric measurement of propidium iodide uptake as well as by optical analysis of cell morphology. Only wildtype Bcl-2 had the ability to efficiently protect from ceramide-mediated ciPCD, whereas expression of Bcl-2 solely at mitochondria, the ER, or the cytosol/nucleus did not prevent ceramide-mediated ciPCD. Our data suggest a combined requirement for both mitochondria and the ER in the induction and the signaling pathways of ciPCD mediated by ceramide

  7. Coxsackievirus-mediated hyperglycemia is enhanced by reinfection and this occurs independent of T cells

    International Nuclear Information System (INIS)

    Horwitz, Marc S.; Ilic, Alex; Fine, Cody; Rodriguez, Enrique; Sarvetnick, Nora

    2003-01-01

    The induction of autoimmunity by viruses has been hypothesized to occur by a number of mechanisms. Coxsackievirus B4 (CB4) induces hyperglycemia in SJL mice resembling diabetes in humans. While virus is effectively cleared within 2 weeks, hyperglycemia does not appear until about 8-12 weeks postinfection at a time when replicative virus is no longer detectable. In SJL mice, reinfection with CB4 enhanced the development of hyperglycemia. As predicted, the immune system responded more rapidly to the second infection and virus was cleared more swiftly. However, while infiltrating T cells were found within the pancreas, depletion of the CD4 T cell population prior to secondary infection or use of CD8 knock-out mice had no effect on the development of virus-mediated hyperglycemia. In conclusion, enhanced hyperglycemia induced by CB4 occurs independent of the T cell response

  8. Frontal cortex gray matter volume alterations in pathological gambling occur independently from substance use disorder.

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    Zois, Evangelos; Kiefer, Falk; Lemenager, Tagrid; Vollstädt-Klein, Sabine; Mann, Karl; Fauth-Bühler, Mira

    2017-05-01

    Neuroimaging in pathological gambling (PG) allows studying brain structure independent of pharmacological/neurotoxic effects occurring in substance addiction. Because of high comorbidity of PG with substance use disorder (SUD), first results on structural deficits in PG are controversial. The current investigation is the first to examine gray matter (GM) volume alterations in PG controlling for the impact of SUD by comparing non-comorbid (PG PURE ) and two comorbid (PG ALCOHOL and PG POLY ) groups. Two hundred and five individuals were included in the analysis: 107 patients diagnosed with PG and 98 healthy controls (HCs). We employed voxel-based morphometry to look for GM volume differences between the groups controlling for age, smoking and depression. GM decreases in the superior medial and orbital frontal cortex occur independently of substance use in PG PURE compared with HCs. The frontal pattern of GM decrease was comparable with PG ALCOHOL group where additionally GM volume was decreased in the anterior cingulate but increased in the amygdala. Moreover, regions in PG ALCOHOL + POLY with reduced GM volume were the medial frontal, anterior cingulate and occipital lobe regions. PG ALCOHOL + POLY not only exhibited structural deficits in comparison with HCs but also relative to PG PURE in the precuneus and post-central gyrus. We demonstrated specific frontal cortex GM deficits in PG without SUD comorbidities. Whereas some target regions reported in earlier studies might result from comorbid substance abuse, there seems to be a core set of frontal alterations associated with addicted gambling behaviour independent of toxic substance effects. © 2016 Society for the Study of Addiction.

  9. Inhibition of early T cell cytokine production by arsenic trioxide occurs independently of Nrf2.

    Directory of Open Access Journals (Sweden)

    Kelly R VanDenBerg

    Full Text Available Nuclear factor erythroid 2-related factor 2 (Nrf2 is a stress-activated transcription factor that induces a variety of cytoprotective genes. Nrf2 also mediates immunosuppressive effects in multiple inflammatory models. Upon activation, Nrf2 dissociates from its repressor protein, Keap1, and translocates to the nucleus where it induces Nrf2 target genes. The Nrf2-Keap1 interaction is disrupted by the environmental toxicant and chemotherapeutic agent arsenic trioxide (ATO. The purpose of the present study was to determine the effects of ATO on early events of T cell activation and the role of Nrf2 in those effects. The Nrf2 target genes Hmox-1, Nqo-1, and Gclc were all upregulated by ATO (1-2 μM in splenocytes derived from wild-type, but not Nrf2-null, mice, suggesting that Nrf2 is activated by ATO in splenocytes. ATO also inhibited IFNγ, IL-2, and GM-CSF mRNA and protein production in wild-type splenocytes activated with the T cell activator, anti-CD3/anti-CD28. However, ATO also decreased production of these cytokines in activated splenocytes from Nrf2-null mice, suggesting the inhibition is independent of Nrf2. Interestingly, ATO inhibited TNFα protein secretion, but not mRNA expression, in activated splenocytes suggesting the inhibition is due to post-transcriptional modification. In addition, c-Fos DNA binding was significantly diminished by ATO in wild-type and Nrf2-null splenocytes activated with anti-CD3/anti-CD28, consistent with the observed inhibition of cytokine production by ATO. Collectively, this study suggests that although ATO activates Nrf2 in splenocytes, inhibition of early T cell cytokine production by ATO occurs independently of Nrf2 and may instead be due to impaired AP-1 DNA binding.

  10. Independent occurence of gastric tumor and intestinal metaplasia by x-irradiation

    International Nuclear Information System (INIS)

    Watanabe, Hiromitsu; Ito, Akihiro

    1986-01-01

    The selective occurence of gastric tumors and intestinal metaplasias in the stomach by X-irradiation were described both in mice and rats. The appearance of both lesions was greatly influenced by animal's strains in both species and also by the sex in rats. A few gastric tumors were observed in the animals given a high does with spilt into low doses of X-irradiation. The adequate dose for gastric tumorigenesis may be around 20 Gy in mice and 15 Gy in rats. A good relationship between X-ray dose and incidence of gastric tumor was observed in ICR mice. Frequency of intestinal metaplasia by X-irradiation was much higher in rats compared to that in mice. X-ray dose requested for moderate and induction of intestinal metaplasia was decreased with a dose which was induced erosion and gastric tumor. It has been empirically clarified that an elevation of pH value in the gastric juice is one of the principal factors responsible for the development of intestinal metaplasia in the gastric mucosa among the conditions thus for introduced. In this article, we have introduced the relevant examples about intestinal metaplasia without carcinogenic insult, and the relationship between gastric tumor and intestinal metaplasia were described. The intestinal metaplasia was not always observed within or adjacent to neoplastic gastric glands. A combined treatment of X-ray and MNNG was not effective for gastric tumor and frequency of intestinal metaplasia was inversely related to the incidence of gastric tumors. In conclusion, occurrence of gastric tumor and intestinal metaplasia may be independent, and intestinal metaplasia might not be a prerequite for the occurrence of gastric tumor. (author)

  11. Ozone-induced gene expression occurs via ethylene-dependent and -independent signalling.

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    Grimmig, Bernhard; Gonzalez-Perez, Maria N; Leubner-Metzger, Gerhard; Vögeli-Lange, Regina; Meins, Fred; Hain, Rüdiger; Penuelas, Josep; Heidenreich, Bernd; Langebartels, Christian; Ernst, Dieter; Sandermann, Heinrich

    2003-03-01

    Recent studies suggest that ethylene is involved in signalling ozone-induced gene expression. We show here that application of ozone increased glucuronidase (GUS) expression of chimeric reporter genes regulated by the promoters of the tobacco class I beta-1,3-glucanases (GLB and Gln2) and the grapevine resveratrol synthase (Vst1) genes in transgenic tobacco leaves. 5'-deletion analysis of the class I beta-1,3-glucanase promoter revealed that ozone-induced gene regulation is mainly mediated by the distal enhancer region containing the positively acting ethylene-responsive element (ERE). In addition, application of 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, blocked ozone-induced class I beta-1,3-glucanase promoter activity. Enhancer activity and ethylene-responsiveness depended on the integrity of the GCC boxes, cis-acting elements present in the ERE of the class I beta-1,3-glucanase and the basic-type pathogenesis-related PR-1 protein (PRB-1b) gene promoters. The minimal PRB-1b promoter containing only the ERE with intact GCC boxes, was sufficient to confer 10-fold ozone inducibility to a GUS-reporter gene, while a substitution mutation in the GCC box abolished ozone responsiveness. The ERE region of the class I beta-1,3-glucanase promoter containing two intact GCC boxes confered strong ozone inducibility to a minimal cauliflower mosaic virus (CaMV) 35S RNA promoter, whereas two single-base substitution in the GCC boxes resulted in a complete loss of ozone inducibility. Taken together, these datastrongly suggest that ethylene is signalling ozone-induced expression of class I beta-l,3-glucanase and PRB-1b genes. Promoter analysis of the stilbene synthase Vst1 gene unravelled different regions for ozone and ethylene-responsiveness. Application of 1-MCP blocked ethylene-induced Vst1 induction, but ozone induction was not affected. This shows that ozone-induced gene expression occurs via at least two different signalling mechanisms and suggests an

  12. Anticipation of visual form independent of knowing where the form will occur/

    DEFF Research Database (Denmark)

    Bruhn, Pernille; Bundesen, Claus

    2012-01-01

    We investigated how selective preparation for specific forms is affected by concurrent preknowledge of location when upcoming visual stimuli are anticipated. In three experiments, participants performed a two-choice response time (RT) task in which they discriminated between standard upright...... of our effects suggested that preknowledge of form and location, respectively, affected two functionally independent, serial stages of processing. We suggest that the two stages were, first, direction of attention to the stimulus location and, subsequently, discrimination between upright and rotated...... stimuli. Presumably, preknowledge of location advanced the point in time at which attention was directed at the stimulus location, whereas preknowledge of form reduced the time subsequently taken for stimulus discrimination....

  13. Rapid bursts of androgen-binding protein (Abp) gene duplication occurred independently in diverse mammals.

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    Laukaitis, Christina M; Heger, Andreas; Blakley, Tyler D; Munclinger, Pavel; Ponting, Chris P; Karn, Robert C

    2008-02-12

    The draft mouse (Mus musculus) genome sequence revealed an unexpected proliferation of gene duplicates encoding a family of secretoglobin proteins including the androgen-binding protein (ABP) alpha, beta and gamma subunits. Further investigation of 14 alpha-like (Abpa) and 13 beta- or gamma-like (Abpbg) undisrupted gene sequences revealed a rich diversity of developmental stage-, sex- and tissue-specific expression. Despite these studies, our understanding of the evolution of this gene family remains incomplete. Questions arise from imperfections in the initial mouse genome assembly and a dearth of information about the gene family structure in other rodents and mammals. Here, we interrogate the latest 'finished' mouse (Mus musculus) genome sequence assembly to show that the Abp gene repertoire is, in fact, twice as large as reported previously, with 30 Abpa and 34 Abpbg genes and pseudogenes. All of these have arisen since the last common ancestor with rat (Rattus norvegicus). We then demonstrate, by sequencing homologs from species within the Mus genus, that this burst of gene duplication occurred very recently, within the past seven million years. Finally, we survey Abp orthologs in genomes from across the mammalian clade and show that bursts of Abp gene duplications are not specific to the murid rodents; they also occurred recently in the lagomorph (rabbit, Oryctolagus cuniculus) and ruminant (cattle, Bos taurus) lineages, although not in other mammalian taxa. We conclude that Abp genes have undergone repeated bursts of gene duplication and adaptive sequence diversification driven by these genes' participation in chemosensation and/or sexual identification.

  14. Spontaneous food allergy in Was-/- mice occurs independent of FcεRI-mediated mast cell activation.

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    Lexmond, W S; Goettel, J A; Sallis, B F; McCann, K; Rings, E H H M; Jensen-Jarolim, E; Nurko, S; Snapper, S B; Fiebiger, E

    2017-12-01

    Food allergies are a growing health problem, and the development of therapies that prevent disease onset is limited by the lack of adjuvant-free experimental animal models. We compared allergic sensitization in patients with food allergy or Wiskott-Aldrich syndrome (WAS) and defined whether spontaneous disease in Was -/- mice recapitulates the pathology of a conventional disease model and/or human food allergy. Comparative ImmunoCAP ISAC microarray was performed in patients with food allergy or WAS. Spontaneous food allergy in Was -/- mice was compared to an adjuvant-based model in wild-type mice (WT-OVA/alum). Intestinal and systemic anaphylaxis was assessed, and the role of the high-affinity IgE Fc receptor (FcεRI) in allergic sensitization was evaluated using Was -/- Fcer1a -/- mice. Polysensitization to food was detected in both WAS and food-allergic patients which was recapitulated in the Was -/- model. Oral administration of ovalbumin (OVA) in Was -/- mice induced low titers of OVA-specific IgE compared to the WT-OVA/alum model. Irrespectively, 79% of Was -/- mice developed allergic diarrhea following oral OVA challenge. Systemic anaphylaxis occurred in Was -/- mice (95%) with a mortality rate >50%. Spontaneous sensitization and intestinal allergy occurred independent of FcεRI expression on mast cells (MCs) and basophils. Was -/- mice provide a model of food allergy with the advantage of mimicking polysensitization and low food-antigen IgE titers as observed in humans with clinical food allergy. This model will facilitate studies on aberrant immune responses during spontaneous disease development. Our results imply that therapeutic targeting of the IgE/FcεRI activation cascade will not affect sensitization to food. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

  15. Independent Versus Co-occurring Substance Use in Relation to Gambling Outcomes in Older Adolescents and Young Adults.

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    Cronce, Jessica M; Bittinger, Joyce N; Di Lodovico, Cory M; Liu, Junny

    2017-05-01

    Gambling is prevalent among college students and can be associated with significant negative consequences. Students who report gambling also tend to report use of alcohol and cannabis, but little research has explored the associated risks of using these substances in relation to gambling episodes. This study explored associations between the independent and co-occurring use of alcohol and cannabis before/during gambling episodes and gambling outcomes. Students (n = 1,834) completed an online survey that included measures of gambling frequency, amount lost, negative gambling consequences, gambling problem severity, and substance use. As hypothesized, individuals who reported using either alcohol or cannabis alone or both substances before/while gambling endorsed greater gambling quantity, frequency, negative consequences, and problem severity than individuals who used alcohol and cannabis in general but denied use of either substance before/while gambling. Use of both substances compared to use of alcohol alone was associated with greater gambling quantity, frequency, and negative consequences, although these groups did not differ on gambling problem severity. Cannabis use alone was no different on any outcome than use of both substances, and alcohol use alone was no different than cannabis use alone on any outcome. Use of cannabis alone before/while gambling may confer the same level of risk for negative gambling outcomes as use of both cannabis and alcohol. Prevention efforts may, therefore, benefit from targeting cannabis use in relation to gambling. Additional investigation is needed in light of recent and upcoming state legislation on the legalization of cannabis. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  16. Cadmium-induced glutathionylation of actin occurs through a ROS-independent mechanism: Implications for cytoskeletal integrity

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    Choong, Grace; Liu, Ying; Xiao, Weiqun; Templeton, Douglas M., E-mail: doug.templeton@utoronto.ca

    2013-10-15

    Cadmium disrupts the actin cytoskeleton in rat mesangial cells, and we have previously shown that this involves a complex interplay involving activation of kinase signaling, protein translocation, and disruption of focal adhesions. Here we investigate the role that glutathionylation of actin plays in Cd{sup 2+}-associated cytoskeletal reorganization. Low concentrations of Cd{sup 2+} (0.5–2 μM) caused an increase in actin glutathionylation by 6 h, whereas at higher concentrations glutathionylation remained at basal levels. Although oxidation with diamide increased glutathionylation, reactive oxygen species (ROS) were not involved in the Cd{sup 2+}-dependent effect, as only Cd{sup 2+} concentrations above 2 μM were sufficient to increase ROS. However, low [Cd{sup 2+}] increased total glutathione levels without affecting the ratio of reduced/oxidized glutathione, and inhibition of glutathione synthesis suppressed actin glutathionylation. Cadmium increased the activity of the enzyme glutaredoxin, which influences the equilibrium between glutathionylated and deglutathionylated proteins and thus may influence levels of glutathionylated actin. Together these observations show that cadmium-dependent effects on actin glutathionylation are affected by glutathione metabolism and not by direct effects of ROS on thiol chemistry. In vitro polymerization assays with glutathionylated actin show a decreased rate of polymerization. In contrast, immunofluorescence of cytoskeletal structure in intact cells suggests that increases in actin glutathionylation accompanying increased glutathione levels occurring under low Cd{sup 2+} exposure are protective in vivo, with cytoskeletal disruption ensuing only when higher Cd{sup 2+} concentrations increase ROS levels and prevent an increase in actin–glutathione conjugates. - Highlights: • Cadmium disrupts the actin cytoskeleton in mesangial cells. • Cadmium induces glutathionylation of actin at low concentrations.

  17. Cadmium-induced glutathionylation of actin occurs through a ROS-independent mechanism: Implications for cytoskeletal integrity

    International Nuclear Information System (INIS)

    Choong, Grace; Liu, Ying; Xiao, Weiqun; Templeton, Douglas M.

    2013-01-01

    Cadmium disrupts the actin cytoskeleton in rat mesangial cells, and we have previously shown that this involves a complex interplay involving activation of kinase signaling, protein translocation, and disruption of focal adhesions. Here we investigate the role that glutathionylation of actin plays in Cd 2+ -associated cytoskeletal reorganization. Low concentrations of Cd 2+ (0.5–2 μM) caused an increase in actin glutathionylation by 6 h, whereas at higher concentrations glutathionylation remained at basal levels. Although oxidation with diamide increased glutathionylation, reactive oxygen species (ROS) were not involved in the Cd 2+ -dependent effect, as only Cd 2+ concentrations above 2 μM were sufficient to increase ROS. However, low [Cd 2+ ] increased total glutathione levels without affecting the ratio of reduced/oxidized glutathione, and inhibition of glutathione synthesis suppressed actin glutathionylation. Cadmium increased the activity of the enzyme glutaredoxin, which influences the equilibrium between glutathionylated and deglutathionylated proteins and thus may influence levels of glutathionylated actin. Together these observations show that cadmium-dependent effects on actin glutathionylation are affected by glutathione metabolism and not by direct effects of ROS on thiol chemistry. In vitro polymerization assays with glutathionylated actin show a decreased rate of polymerization. In contrast, immunofluorescence of cytoskeletal structure in intact cells suggests that increases in actin glutathionylation accompanying increased glutathione levels occurring under low Cd 2+ exposure are protective in vivo, with cytoskeletal disruption ensuing only when higher Cd 2+ concentrations increase ROS levels and prevent an increase in actin–glutathione conjugates. - Highlights: • Cadmium disrupts the actin cytoskeleton in mesangial cells. • Cadmium induces glutathionylation of actin at low concentrations. • Glutathionylation requires glutathione

  18. Respiration and substrate transport rates as well as reactive oxygen species production distinguish mitochondria from brain and liver.

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    Gusdon, Aaron M; Fernandez-Bueno, Gabriel A; Wohlgemuth, Stephanie; Fernandez, Jenelle; Chen, Jing; Mathews, Clayton E

    2015-09-10

    Aberrant mitochondrial function, including excessive reactive oxygen species (ROS) production, has been implicated in the pathogenesis of human diseases. The use of mitochondrial inhibitors to ascertain the sites in the electron transport chain (ETC) resulting in altered ROS production can be an important tool. However, the response of mouse mitochondria to ETC inhibitors has not been thoroughly assessed. Here we set out to characterize the differences in phenotypic response to ETC inhibitors between the more energetically demanding brain mitochondria and less energetically demanding liver mitochondria in commonly utilized C57BL/6J mice. We show that in contrast to brain mitochondria, inhibiting distally within complex I or within complex III does not increase liver mitochondrial ROS production supported by complex I substrates, and liver mitochondrial ROS production supported by complex II substrates occurred primarily independent of membrane potential. Complex I, II, and III enzymatic activities and membrane potential were equivalent between liver and brain and responded to ETC. inhibitors similarly. Brain mitochondria exhibited an approximately two-fold increase in complex I and II supported respiration compared with liver mitochondria while exhibiting similar responses to inhibitors. Elevated NADH transport and heightened complex II-III coupled activity accounted for increased complex I and II supported respiration, respectively in brain mitochondria. We conclude that important mechanistic differences exist between mouse liver and brain mitochondria and that mouse mitochondria exhibit phenotypic differences compared with mitochondria from other species.

  19. PKC-Dependent GlyT1 Ubiquitination Occurs Independent of Phosphorylation: Inespecificity in Lysine Selection for Ubiquitination.

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    Susana P Barrera

    Full Text Available Neurotransmitter transporter ubiquitination is emerging as the main mechanism for endocytosis and sorting of cargo into lysosomes. In this study, we demonstrate PKC-dependent ubiquitination of three different isoforms of the glycine transporter 1 (GlyT1. Incubation of cells expressing transporter with the PKC activator phorbol ester induced a dramatic, time-dependent increase in GlyT1 ubiquitination, followed by accumulation of GlyT1 in EEA1 positive early endosomes. This occurred via a mechanism that was abolished by inhibition of PKC. GlyT1 endocytosis was confirmed in both retinal sections and primary cultures of mouse amacrine neurons. Replacement of only all lysines in the N-and C-termini to arginines prevented ubiquitination and endocytosis, displaying redundancy in the mechanism of ubiquitination. Interestingly, a 40-50% reduction in glycine uptake was detected in phorbol-ester stimulated cells expressing the WT-GlyT1, whereas no significant change was for the mutant protein, demonstrating that endocytosis participates in the reduction of uptake. Consistent with previous findings for the dopamine transporter DAT, ubiquitination of GlyT1 tails functions as sorting signal to deliver transporter into the lysosome and removal of ubiquitination sites dramatically attenuated the rate of GlyT1 degradation. Finally, we showed for the first time that PKC-dependent GlyT1 phosphorylation was not affected by removal of ubiquitination sites, suggesting separate PKC-dependent signaling events for these posttranslational modifications.

  20. Citrate and succinate uptake by potato mitochondria

    International Nuclear Information System (INIS)

    Jung, D.W.; Laties, G.G.

    1979-01-01

    Potato mitochondria, in the absence of respiration, have a very low capacity for uptake by exchange with endogenous anions, taking up only 2.4 nanomoles citrate and 2.0 nanomoles succinate per milligram protein. Maximum citrate uptake of over 17 nanomoles per milligram protein occurs in the presence of inorganic phosphate, a dicarboxylic acid, and an external energy source (NADH), conditions where net anion accumulation proceeds, mediated by the interlinking of the inorganic phosphate, dicarboxylate, and tricarboxylate carriers. Maximum succinate uptake in the absence of respiratory inhibitors requires only added inorganic phosphate. Compounds which inhibit respiration (antimycin), the exchange carriers (mersalyl and benzylmalonate), or the establishment of the membrane proton motive force (uncouplers) reduce substrate accumulation. A potent inhibitor of the citrate carrier in animal mitochondria, 1,2,3-benzenetricarboxylic acid, does not inhibit citrate uptake in potato mitochondria. Citrate uptake is reduced by concurrent ADP phosphorylation and this reduction is sensitive to oligomycin. The initiation of state 3 after a 3-minute substrate state results in a reduction of the steady-state of citrate uptake by approximately 50%. Accumulation of succinate initially is inhibited by increasing sucrose concentration in the reaction medium from 50 to 400 millimolar. Limited substrate uptake is one of the factors responsible for the often observed depressed initial state 3 respiration rates in many mitochondrial preparations. Since nonlimiting levels of substrate in the matrix cannot be attained by energy-independent exchange, a dependence on respiration for adequate uptake results. Substrate limitation therefore occurs in the matrix for the period of time needed for energy-dependent accumulation of nonlimiting levels

  1. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

    Science.gov (United States)

    Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

    2015-01-01

    Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

  2. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Elisabetta Iessi

    Full Text Available Ezrin belongs to the ERM (ezrin-radixin-moesin protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells.

  3. Mitochondria in neutrophil apoptosis

    NARCIS (Netherlands)

    van Raam, B. J.; Verhoeven, A. J.; Kuijpers, T. W.

    2006-01-01

    Central in the regulation of the short life span of neutrophils are their mitochondria. These organelles hardly contribute to the energy status of neutrophils but play a vital role in the apoptotic process. Not only do the mitochondria contain cytotoxic proteins that are released during apoptosis

  4. Development of the mouse dermal adipose layer occurs independently of subcutaneous adipose tissue and is marked by restricted early expression of FABP4.

    Directory of Open Access Journals (Sweden)

    Kamila Wojciechowicz

    Full Text Available The laboratory mouse is a key animal model for studies of adipose biology, metabolism and disease, yet the developmental changes that occur in tissues and cells that become the adipose layer in mouse skin have received little attention. Moreover, the terminology around this adipose body is often confusing, as frequently no distinction is made between adipose tissue within the skin, and so called subcutaneous fat. Here adipocyte development in mouse dorsal skin was investigated from before birth to the end of the first hair follicle growth cycle. Using Oil Red O staining, immunohistochemistry, quantitative RT-PCR and TUNEL staining we confirmed previous observations of a close spatio-temporal link between hair follicle development and the process of adipogenesis. However, unlike previous studies, we observed that the skin adipose layer was created from cells within the lower dermis. By day 16 of embryonic development (e16 the lower dermis was demarcated from the upper dermal layer, and commitment to adipogenesis in the lower dermis was signalled by expression of FABP4, a marker of adipocyte differentiation. In mature mice the skin adipose layer is separated from underlying subcutaneous adipose tissue by the panniculus carnosus. We observed that the skin adipose tissue did not combine or intermix with subcutaneous adipose tissue at any developmental time point. By transplanting skin isolated from e14.5 mice (prior to the start of adipogenesis, under the kidney capsule of adult mice, we showed that skin adipose tissue develops independently and without influence from subcutaneous depots. This study has reinforced the developmental link between hair follicles and skin adipocyte biology. We argue that because skin adipocytes develop from cells within the dermis and independently from subcutaneous adipose tissue, that it is accurately termed dermal adipose tissue and that, in laboratory mice at least, it represents a separate adipose depot.

  5. Working memory updating occurs independently of the need to maintain task-context: accounting for triggering updating in the AX-CPT paradigm.

    Science.gov (United States)

    Kessler, Yoav; Baruchin, Liad J; Bouhsira-Sabag, Anat

    2017-01-01

    Theoretical models suggest that maintenance and updating are two functional states of working memory (WM), which are controlled by a gate between perceptual information and WM representations. Opening the gate enables updating WM with input, while closing it enables keeping the maintained information shielded from interference. However, it is still unclear when gate opening takes place, and what is the external signal that triggers it. A version of the AX-CPT paradigm was used to examine a recent proposal in the literature, suggesting that updating is triggered whenever the maintenance of the context is necessary for task performance (context-dependent tasks). In four experiments using this paradigm, we show that (1) a task-switching cost takes place in both context-dependent and context-independent trials; (2) task-switching is additive to the dependency effect, and (3) unlike switching cost, the dependency effect is not affected by preparation and, therefore, does not reflect context-updating. We suggest that WM updating is likely to be triggered by a simple mechanism that occurs in each trial of the task regardless of whether maintaining the context is needed or not. The implications for WM updating and its relationship to task-switching are discussed.

  6. Mitochondria in Lung Diseases

    Science.gov (United States)

    Aravamudan, Bharathi; Thompson, Michael A.; Pabelick, Christina M.; Prakash, Y. S.

    2014-01-01

    Summary Mitochondria are autonomous cellular organelles that oversee a variety of functions such as metabolism, energy production, calcium buffering, and cell fate determination. Regulation of their morphology and diverse activities beyond energy production are being recognized as playing major roles in cellular health and dysfunction. This review is aimed at summarizing what is known regarding mitochondrial contributions to pathogenesis of lung diseases. Emphasis is given to understanding the importance of structural and functional aspects of mitochondria in both normal cellular function (based on knowledge from other cell types) and in development and modulation of lung diseases such as asthma, COPD, cystic fibrosis and cancer. Emerging techniques that allow examination of mitochondria, and potential strategies to target mitochondria in the treatment of lung diseases are also discussed. PMID:23978003

  7. F227. PSYCHOLOGICAL TRAUMA OCCURRING DURING ADOLESCENCE IS ASSOCIATED WITH AN INCREASED RISK OF GREATER WAIST CIRCUMFERENCE IN EARLY PSYCHOSIS PATIENTS INDEPENDENTLY OF MEDICATION

    Science.gov (United States)

    Alameda, Luis; Levier, Axel; Golay, Philippe; Gholam-Rezaee, Mehdi; Vandenberghe, Frederik; Delacretaz, Aurélie; Glatard, Anaïs; Dubath, Céline; Do, Kim Q; Eap, Chin B; Conus, Philippe

    2018-01-01

    Abstract Background The high prevalence of obesity in patients suffering from psychosis is a major concern as it dramatically increases the mortality rates of such patients in the long term. The mechanisms by which these patients develop overweight are poorly understood. It has been suggested that exposure to Childhood Trauma (CT) may play a role in the risk for obesity; however, whether this is the case for Early Psychosis (EP) patients and independently of the impact of medication has yet to be investigated. In addition, it is unknown whether the age at the time of exposure to CT can modulate the link between CT and obesity in EP patients. Methods 136 EP patients aged 18–35 were recruited from the Treatment and Early Intervention in Psychosis Program (TIPP-Lausanne). Body Mass Index (BMI), Weight Gain (WG) and Waist Circumference (WC) were measured and monitored prospectively after psychotropic prescription during a follow-up period of 1 year (patients were assessed at baseline, after 1, 2, 3, 6 months and 1 year of antipsychotic treatment). Patients were classified into Early-Trauma if they had faced at least one experience of abuse (physical, sexual, or emotional) or neglect (physical or emotional) before age 12, and Late-Trauma if the exposure had occurred between ages 12 and 16. Linear Mixed effect models with a random intercept were used to investigate the impact of Trauma (early or late) on the metabolic parameters longitudinally, Marko Chain Monte Carlo (MCMC) method was used to adjust these models with sufficiently large number of MCMC iterations. Models were adjusted for age, socioeconomic status, baseline BMI, medication intake prior to the first assessment and during the treatment phase, and by the diagnosis of depression. Results Patients were more likely to have a diagnosis of Schizophrenia (61%; N=83), they had a mean age of 26 at the time of first assessment, and exposure to 1 or more forms of traumatic experiences before 16 years of age was

  8. 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

  9. Sex-specific differences in mitochondria biogenesis, morphology, respiratory function, and ROS homeostasis in young mouse heart and brain.

    Science.gov (United States)

    Khalifa, Abdel Rahman M; Abdel-Rahman, Engy A; Mahmoud, Ali M; Ali, Mohamed H; Noureldin, Maha; Saber, Saber H; Mohsen, Mahmoud; Ali, Sameh S

    2017-03-01

    Sex-specific differences in mitochondrial function and free radical homeostasis are reported in the context of aging but not well-established in pathogeneses occurring early in life. Here, we examine if sex disparity in mitochondria function, morphology, and redox status starts early and hence can be implicated in sexual dimorphism in cardiac as well as neurological disorders prevalent at young age. Although mitochondrial activity in the heart did not significantly vary between sexes, female brain exhibited enhanced respiration and higher reserve capacity. This was associated with lower H 2 O 2 production in female cardiac and brain tissues. Using transmission electron microscopy, we found that the number of female cardiac mitochondria is moderately greater (117 ± 3%, P  = 0.049, N  = 4) than male's, which increased significantly for cortical mitochondria (134 ± 4%, P  = 0.001, N  = 4). However, male's cardiac mitochondria exhibited fragmented, circular, and smaller mitochondria relative to female's mitochondria, while no morphologic sex-dependent differences were observed in cortical mitochondria. No sex differences were detected in Nox2 and Nox4 proteins or O 2 -consuming/H 2 O 2 -producing activities in brain homogenate or synaptosomes. However, a strong trend of increased EPR-detected NOX superoxide in male synaptosomes hinted at higher superoxide dismutase activity in female brains, which was confirmed by two independent protocols. We also provide direct evidence that respiring mitochondria generally produce an order-of-magnitude lower reactive oxygen species (ROS) proportions than currently estimated. Our results indicate that sex differences in mitochondrial biogenesis, bioenergetics, and morphology may start at young age and that sex-dependent SOD capacity may be responsible for differences in ROS homeostasis in heart and brain. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological

  10. Mitochondria: more than just a powerhouse.

    Science.gov (United States)

    McBride, Heidi M; Neuspiel, Margaret; Wasiak, Sylwia

    2006-07-25

    Pioneering biochemical studies have long forged the concept that the mitochondria are the 'energy powerhouse of the cell'. These studies, combined with the unique evolutionary origin of the mitochondria, led the way to decades of research focusing on the organelle as an essential, yet independent, functional component of the cell. Recently, however, our conceptual view of this isolated organelle has been profoundly altered with the discovery that mitochondria function within an integrated reticulum that is continually remodeled by both fusion and fission events. The identification of a number of proteins that regulate these activities is beginning to provide mechanistic details of mitochondrial membrane remodeling. However, the broader question remains regarding the underlying purpose of mitochondrial dynamics and the translation of these morphological transitions into altered functional output. One hypothesis has been that mitochondrial respiration and metabolism may be spatially and temporally regulated by the architecture and positioning of the organelle. Recent evidence supports and expands this idea by demonstrating that mitochondria are an integral part of multiple cell signaling cascades. Interestingly, proteins such as GTPases, kinases and phosphatases are involved in bi-directional communication between the mitochondrial reticulum and the rest of the cell. These proteins link mitochondrial function and dynamics to the regulation of metabolism, cell-cycle control, development, antiviral responses and cell death. In this review we will highlight the emerging evidence that provides molecular definition to mitochondria as a central platform in the execution of diverse cellular events.

  11. Functional Mitochondria in Health and Disease.

    Science.gov (United States)

    Herst, Patries M; Rowe, Matthew R; Carson, Georgia M; Berridge, Michael V

    2017-01-01

    The ability to rapidly adapt cellular bioenergetic capabilities to meet rapidly changing environmental conditions is mandatory for normal cellular function and for cancer progression. Any loss of this adaptive response has the potential to compromise cellular function and render the cell more susceptible to external stressors such as oxidative stress, radiation, chemotherapeutic drugs, and hypoxia. Mitochondria play a vital role in bioenergetic and biosynthetic pathways and can rapidly adjust to meet the metabolic needs of the cell. Increased demand is met by mitochondrial biogenesis and fusion of individual mitochondria into dynamic networks, whereas a decrease in demand results in the removal of superfluous mitochondria through fission and mitophagy. Effective communication between nucleus and mitochondria (mito-nuclear cross talk), involving the generation of different mitochondrial stress signals as well as the nuclear stress response pathways to deal with these stressors, maintains bioenergetic homeostasis under most conditions. However, when mitochondrial DNA (mtDNA) mutations accumulate and mito-nuclear cross talk falters, mitochondria fail to deliver critical functional outputs. Mutations in mtDNA have been implicated in neuromuscular and neurodegenerative mitochondriopathies and complex diseases such as diabetes, cardiovascular diseases, gastrointestinal disorders, skin disorders, aging, and cancer. In some cases, drastic measures such as acquisition of new mitochondria from donor cells occurs to ensure cell survival. This review starts with a brief discussion of the evolutionary origin of mitochondria and summarizes how mutations in mtDNA lead to mitochondriopathies and other degenerative diseases. Mito-nuclear cross talk, including various stress signals generated by mitochondria and corresponding stress response pathways activated by the nucleus are summarized. We also introduce and discuss a small family of recently discovered hormone-like mitopeptides

  12. Functional Mitochondria in Health and Disease

    Directory of Open Access Journals (Sweden)

    Patries M. Herst

    2017-11-01

    Full Text Available The ability to rapidly adapt cellular bioenergetic capabilities to meet rapidly changing environmental conditions is mandatory for normal cellular function and for cancer progression. Any loss of this adaptive response has the potential to compromise cellular function and render the cell more susceptible to external stressors such as oxidative stress, radiation, chemotherapeutic drugs, and hypoxia. Mitochondria play a vital role in bioenergetic and biosynthetic pathways and can rapidly adjust to meet the metabolic needs of the cell. Increased demand is met by mitochondrial biogenesis and fusion of individual mitochondria into dynamic networks, whereas a decrease in demand results in the removal of superfluous mitochondria through fission and mitophagy. Effective communication between nucleus and mitochondria (mito-nuclear cross talk, involving the generation of different mitochondrial stress signals as well as the nuclear stress response pathways to deal with these stressors, maintains bioenergetic homeostasis under most conditions. However, when mitochondrial DNA (mtDNA mutations accumulate and mito-nuclear cross talk falters, mitochondria fail to deliver critical functional outputs. Mutations in mtDNA have been implicated in neuromuscular and neurodegenerative mitochondriopathies and complex diseases such as diabetes, cardiovascular diseases, gastrointestinal disorders, skin disorders, aging, and cancer. In some cases, drastic measures such as acquisition of new mitochondria from donor cells occurs to ensure cell survival. This review starts with a brief discussion of the evolutionary origin of mitochondria and summarizes how mutations in mtDNA lead to mitochondriopathies and other degenerative diseases. Mito-nuclear cross talk, including various stress signals generated by mitochondria and corresponding stress response pathways activated by the nucleus are summarized. We also introduce and discuss a small family of recently discovered hormone

  13. On Cellular Darwinism: Mitochondria.

    Science.gov (United States)

    Bull, Larry

    2016-01-01

    The significant role of mitochondria within cells is becoming increasingly clear. This letter uses the NKCS model of coupled fitness landscapes to explore aspects of organelle-nucleus coevolution. The phenomenon of mitochondrial diversity is allowed to emerge under a simple intracellular evolutionary process, including varying the relative rate of evolution by the organelle. It is shown how the conditions for the maintenance of more than one genetic variant of mitochondria are similar to those previously suggested as needed for the original symbiotic origins of the relationship using the NKCS model.

  14. The Aging Mitochondria

    Directory of Open Access Journals (Sweden)

    Pierre Theurey

    2018-01-01

    Full Text Available Mitochondrial dysfunction is a central event in many pathologies and contributes as well to age-related processes. However, distinguishing between primary mitochondrial dysfunction driving aging and a secondary mitochondrial impairment resulting from other cell alterations remains challenging. Indeed, even though mitochondria undeniably play a crucial role in aging pathways at the cellular and organismal level, the original hypothesis in which mitochondrial dysfunction and production of free radicals represent the main driving force of cell degeneration has been strongly challenged. In this review, we will first describe mitochondrial dysfunctions observed in aged tissue, and how these features have been linked to mitochondrial reactive oxygen species (ROS–mediated cell damage and mitochondrial DNA (mtDNA mutations. We will also discuss the clues that led to consider mitochondria as the starting point in the aging process, and how recent research has showed that the mitochondria aging axis represents instead a more complex and multifactorial signaling pathway. New working hypothesis will be also presented in which mitochondria are considered at the center of a complex web of cell dysfunctions that eventually leads to cell senescence and death.

  15. Social Learning in the Real-World: 'Over-Imitation' Occurs in Both Children and Adults Unaware of Participation in an Experiment and Independently of Social Interaction.

    Directory of Open Access Journals (Sweden)

    Andrew Whiten

    Full Text Available The current study avoided the typical laboratory context to determine instead whether over-imitation-the disposition to copy even visibly, causally unnecessary actions-occurs in a real-world context in which participants are unaware of being in an experiment. We disguised a puzzle-box task as an interactive item available to the public within a science engagement zone of Edinburgh Zoo. As a member of the public approached, a confederate acting as a zoo visitor retrieved a reward from the box using a sequence of actions containing both causally relevant and irrelevant elements. Despite the absence of intentional demonstration, or social pressure to copy, a majority of both child and even adult observers included all causally irrelevant actions in their reproduction. This occurred even though causal irrelevance appeared manifest because of the transparency of the puzzle-box. That over-imitation occurred so readily in a naturalistic context, devoid of social interaction and pressure, suggests that humans are opportunistic social learners throughout the lifespan, copying the actions of other individuals even when these actions are not intentionally demonstrated, and their causal significance is not readily apparent. The disposition to copy comprehensively, even when a mere onlooker, likely provides humans, irrespective of their age, with a powerful mechanism to extract maximal information from the social environment.

  16. Mitochondria and Endothelial Function

    Science.gov (United States)

    Kluge, Matthew A.; Fetterman, Jessica L.; Vita, Joseph A.

    2013-01-01

    In contrast to their role in other cell types with higher energy demands, mitochondria in endothelial cells primarily function in signaling cellular responses to environmental cues. This article provides an overview of key aspects of mitochondrial biology in endothelial cells, including subcellular location, biogenesis, dynamics, autophagy, ROS production and signaling, calcium homeostasis, regulated cell death, and heme biosynthesis. In each section, we introduce key concepts and then review studies showing the importance of that mechanism to endothelial control of vasomotor tone, angiogenesis, and inflammatory activation. We particularly highlight the small number of clinical and translational studies that have investigated each mechanism in human subjects. Finally, we review interventions that target different aspects of mitochondrial function and their effects on endothelial function. The ultimate goal of such research is the identification of new approaches for therapy. The reviewed studies make it clear that mitochondria are important in endothelial physiology and pathophysiology. A great deal of work will be needed, however, before mitochondria-directed therapies are available for the prevention and treatment of cardiovascular disease. PMID:23580773

  17. Vergence-mediated changes in the axis of eye rotation during the human vestibulo-ocular reflex can occur independent of eye position.

    Science.gov (United States)

    Migliaccio, Americo A; Cremer, Phillip D; Aw, Swee T; Halmagyi, G Michael; Curthoys, Ian S; Minor, Lloyd B; Todd, Michael J

    2003-07-01

    The aim of this study was to determine whether vergence-mediated changes in the axis of eye rotation in the human vestibulo-ocular reflex (VOR) would obey Listing's Law (normally associated with saccadic eye movements) independent of the initial eye position. We devised a paradigm for disassociating the saccadic velocity axis from eye position by presenting near and far targets that were centered with respect to one eye. We measured binocular 3-dimensional eye movements using search coils in ten normal subjects and 3-dimensional linear head acceleration using Optotrak in seven normal subjects. The stimuli consisted of passive, unpredictable, pitch head rotations with peak acceleration of approximately 2000 degrees /s(2 )and amplitude of approximately 20 degrees. During the pitch head rotation, each subject fixated straight ahead with one eye, whereas the other eye was adducted 4 degrees during far viewing (94 cm) and 25 degrees during near viewing (15 cm). Our data showed expected compensatory pitch rotations in both eyes, and a vergence-mediated horizontal rotation only in the adducting eye. In addition, during near viewing we observed torsional eye rotations not only in the adducting eye but also in the eye looking straight ahead. In the straight-ahead eye, the change in torsional eye velocity between near and far viewing, which began approximately 40 ms after the start of head rotation, was 10+/-6 degrees /s (mean +/- SD). This change in torsional eye velocity resulted in a 2.4+/-1.5 degrees axis tilt toward Listing's plane in that eye. In the adducting eye, the change in torsional eye velocity between near and far viewing was 16+/-6 degrees /s (mean +/- SD) and resulted in a 4.1+/-1.4 degrees axis tilt. The torsional eye velocities were conjugate and both eyes partially obeyed Listing's Law. The axis of eye rotation tilted in the direction of the line of sight by approximately one-third of the angle between the line of sight and a line orthogonal to Listing

  18. Cerebral blood flow modulation by Basal forebrain or whisker stimulation can occur independently of large cytosolic Ca2+ signaling in astrocytes.

    Science.gov (United States)

    Takata, Norio; Nagai, Terumi; Ozawa, Katsuya; Oe, Yuki; Mikoshiba, Katsuhiko; Hirase, Hajime

    2013-01-01

    We report that a brief electrical stimulation of the nucleus basalis of Meynert (NBM), the primary source of cholinergic projection to the cerebral cortex, induces a biphasic cerebral cortical blood flow (CBF) response in the somatosensory cortex of C57BL/6J mice. This CBF response, measured by laser Doppler flowmetry, was attenuated by the muscarinic type acetylcholine receptor antagonist atropine, suggesting a possible involvement of astrocytes in this type of CBF modulation. However, we find that IP3R2 knockout mice, which lack cytosolic Ca2+ surges in astrocytes, show similar CBF changes. Moreover, whisker stimulation resulted in similar degrees of CBF increase in IP3R2 knockout mice and the background strain C57BL/6J. Our results show that neural activity-driven CBF modulation could occur without large cytosolic increases of Ca2+ in astrocytes.

  19. Toxicity of polyhydroxylated fullerene to mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li-Yun [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Gao, Jia-Ling [Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434023 (China); Gao, Tian; Dong, Ping; Ma, Long; Jiang, Feng-Lei [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu, Yi, E-mail: yiliuchem@whu.edu.cn [State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2016-01-15

    Highlights: • Fullerenol-induced mitochondrial dysfunction was investigated at mitochondrial level. • Fullerenol disturbed mitochondrial inner membrane in polar protein regions. • Fullerenol affected the inner membrane and respiration chain of mitochondria. - Abstract: Mitochondrial dysfunction is considered as a crucial mechanism of nanomaterial toxicity. Herein, we investigated the effects of polyhydroxylated fullerene (C{sub 60}(OH){sub 44}, fullerenol), a model carbon-based nanomaterial with high water solubility, on isolated mitochondria. Our study demonstrated that fullerenol enhanced the permeabilization of mitochondrial inner membrane to H{sup +} and K{sup +} and induced mitochondrial permeability transition (MPT). The fullerenol-induced swelling was dose-dependent and could be effectively inhibited by MPT inhibitors such as cyclosporin A (CsA), adenosine diphosphate (ADP), ruthenium red (RR) and ethylenediaminetetraacetic acid (EDTA). After treating the mitochondria with fullerenol, the mitochondrial membrane potential (MMP) was found collapsed in a concentration-independent manner. The fluorescence anisotropy of hematoporphyrin (HP) changed significantly with the addition of fullerenol, while that of 1,6-diphenyl-hexatriene (DPH) changed slightly. Moreover, a decrease of respiration state 3 and increase of respiration state 4 were observed when mitochondria were energized with complex II substrate succinate. The results of transmission electron microscopy (TEM) provided direct evidence that fullerenol damaged the mitochondrial ultrastructure. The investigations can provide comprehensive information to elucidate the possible toxic mechanism of fullerenols at subcellular level.

  20. Natural selection of mitochondria during somatic lifetime promotes healthy aging

    DEFF Research Database (Denmark)

    Rodell, Anders; Rasmussen, Lene J; Bergersen, Linda H

    2013-01-01

    Stimulation of mitochondrial biogenesis during life-time challenges both eliminates disadvantageous properties and drives adaptive selection of advantageous phenotypic variations. Intermittent fission and fusion of mitochondria provide specific targets for health promotion by brief temporal...... stressors, interspersed with periods of recovery and biogenesis. For mitochondria, the mechanisms of selection, variability, and heritability, are complicated by interaction of two independent genomes, including the multiple copies of DNA in each mitochondrion, as well as the shared nuclear genome of each...

  1. α-Synuclein-induced dopaminergic neurodegeneration in a rat model of Parkinson's disease occurs independent of ATP13A2 (PARK9).

    Science.gov (United States)

    Daniel, Guillaume; Musso, Alessandra; Tsika, Elpida; Fiser, Aris; Glauser, Liliane; Pletnikova, Olga; Schneider, Bernard L; Moore, Darren J

    2015-01-01

    Mutations in the ATP13A2 (PARK9) gene cause early-onset, autosomal recessive Parkinson's disease (PD) and Kufor-Rakeb syndrome. ATP13A2 mRNA is spliced into three distinct isoforms encoding a P5-type ATPase involved in regulating heavy metal transport across vesicular membranes. Here, we demonstrate that three ATP13A2 mRNA isoforms are expressed in the normal human brain and are modestly increased in the cingulate cortex of PD cases. ATP13A2 can mediate protection toward a number of stressors in mammalian cells and can protect against α-synuclein-induced toxicity in cellular and invertebrate models of PD. Using a primary cortical neuronal model combined with lentiviral-mediated gene transfer, we demonstrate that human ATP13A2 isoforms 1 and 2 display selective neuroprotective effects toward toxicity induced by manganese and hydrogen peroxide exposure through an ATPase-independent mechanism. The familial PD mutations, F182L and G504R, abolish the neuroprotective effects of ATP13A2 consistent with a loss-of-function mechanism. We further demonstrate that the AAV-mediated overexpression of human ATP13A2 is not sufficient to attenuate dopaminergic neurodegeneration, neuropathology, and striatal dopamine and motoric deficits induced by human α-synuclein expression in a rat model of PD. Intriguingly, the delivery of an ATPase-deficient form of ATP13A2 (D513N) to the substantia nigra is sufficient to induce dopaminergic neuronal degeneration and motor deficits in rats, potentially suggesting a dominant-negative mechanism of action. Collectively, our data demonstrate a distinct lack of ATP13A2-mediated protection against α-synuclein-induced neurotoxicity in the rat nigrostriatal dopaminergic pathway, and limited neuroprotective capacity overall, and raise doubts about the potential of ATP13A2 as a therapeutic target for PD. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. β cell membrane remodelling and procoagulant events occur in inflammation-driven insulin impairment: a GLP-1 receptor dependent and independent control.

    Science.gov (United States)

    Gleizes, Céline; Kreutter, Guillaume; Abbas, Malak; Kassem, Mohamad; Constantinescu, Andrei Alexandru; Boisramé-Helms, Julie; Yver, Blandine; Toti, Florence; Kessler, Laurence

    2016-02-01

    Inflammation and hyperglycaemia are associated with a prothrombotic state. Cell-derived microparticles (MPs) are the conveyors of active procoagulant tissue factor (TF) and circulate at high concentration in diabetic patients. Liraglutide, a glucagon-like peptide (GLP)-1 analogue, is known to promote insulin secretion and β-cell preservation. In this in vitro study, we examined the link between insulin impairment, procoagulant activity and plasma membrane remodelling, under inflammatory conditions. Rin-m5f β-cell function, TF activity mediated by MPs and their modulation by 1 μM liraglutide were examined in a cell cross-talk model. Methyl-β-cyclodextrine (MCD), a cholesterol depletor, was used to evaluate the involvement of raft on TF activity, MP shedding and insulin secretion as well as Soluble N-éthylmaleimide-sensitive-factor Attachment protein Receptor (SNARE)-dependent exocytosis. Cytokines induced a two-fold increase in TF activity at MP surface that was counteracted by liraglutide. Microparticles prompted TF activity on the target cells and a two-fold decrease in insulin secretion via protein kinase A (PKA) and p38 signalling, that was also abolished by liraglutide. Large lipid raft clusters were formed in response to cytokines and liraglutide or MCD-treated cells showed similar patterns. Cells pre-treated by saturating concentration of the GLP-1r antagonist exendin (9-39), showed a partial abolishment of the liraglutide-driven insulin secretion and liraglutide-decreased TF activity. Measurement of caspase 3 cleavage and MP shedding confirmed the contribution of GLP-1r-dependent and -independent pathways. Our results confirm an integrative β-cell response to GLP-1 that targets receptor-mediated signalling and membrane remodelling pointing at the coupling of insulin secretion and inflammation-driven procoagulant events. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and

  3. Ribosomal protein S14 transcripts are edited in Oenothera mitochondria.

    Science.gov (United States)

    Schuster, W; Unseld, M; Wissinger, B; Brennicke, A

    1990-01-01

    The gene encoding ribosomal protein S14 (rps14) in Oenothera mitochondria is located upstream of the cytochrome b gene (cob). Sequence analysis of independently derived cDNA clones covering the entire rps14 coding region shows two nucleotides edited from the genomic DNA to the mRNA derived sequences by C to U modifications. A third editing event occurs four nucleotides upstream of the AUG initiation codon and improves a potential ribosome binding site. A CGG codon specifying arginine in a position conserved in evolution between chloroplasts and E. coli as a UGG tryptophan codon is not edited in any of the cDNAs analysed. An inverted repeat 3' of an unidentified open reading frame is located upstream of the rps14 gene. The inverted repeat sequence is highly conserved at analogous regions in other Oenothera mitochondrial loci. Images PMID:2326162

  4. 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.

  5. Mature Erythrocytes of Iguana iguana (Squamata, Iguanidae Possess Functional Mitochondria.

    Directory of Open Access Journals (Sweden)

    Giuseppina Di Giacomo

    Full Text Available Electron microscopy analyses of Iguana iguana blood preparations revealed the presence of mitochondria within erythrocytes with well-structured cristae. Fluorescence microscopy analyses upon incubation with phalloidin-FITC, Hoechst 33342 and mitochondrial transmembrane potential (Δψm-sensitive probe MitoTracker Red indicated that mitochondria i widely occur in erythrocytes, ii are polarized, and iii seem to be preferentially confined at a "perinuclear" region, as confirmed by electron microscopy. The analysis of NADH-dependent oxygen consumption showed that red blood cells retain the capability to consume oxygen, thereby providing compelling evidence that mitochondria of Iguana erythrocytes are functional and capable to perform oxidative phosphorylation.

  6. Mature Erythrocytes of Iguana iguana (Squamata, Iguanidae) Possess Functional Mitochondria.

    Science.gov (United States)

    Di Giacomo, Giuseppina; Campello, Silvia; Corrado, Mauro; Di Giambattista, Livia; Cirotti, Claudia; Filomeni, Giuseppe; Gentile, Gabriele

    2015-01-01

    Electron microscopy analyses of Iguana iguana blood preparations revealed the presence of mitochondria within erythrocytes with well-structured cristae. Fluorescence microscopy analyses upon incubation with phalloidin-FITC, Hoechst 33342 and mitochondrial transmembrane potential (Δψm)-sensitive probe MitoTracker Red indicated that mitochondria i) widely occur in erythrocytes, ii) are polarized, and iii) seem to be preferentially confined at a "perinuclear" region, as confirmed by electron microscopy. The analysis of NADH-dependent oxygen consumption showed that red blood cells retain the capability to consume oxygen, thereby providing compelling evidence that mitochondria of Iguana erythrocytes are functional and capable to perform oxidative phosphorylation.

  7. Calcium regulates cell death in cancer: Roles of the mitochondria and mitochondria-associated membranes (MAMs).

    Science.gov (United States)

    Danese, Alberto; Patergnani, Simone; Bonora, Massimo; Wieckowski, Mariusz R; Previati, Maurizio; Giorgi, Carlotta; Pinton, Paolo

    2017-08-01

    Until 1972, the term 'apoptosis' was used to differentiate the programmed cell death that naturally occurs in organismal development from the acute tissue death referred to as necrosis. Many studies on cell death and programmed cell death have been published and most are, at least to some degree, related to cancer. Some key proteins and molecular pathways implicated in cell death have been analyzed, whereas others are still being actively researched; therefore, an increasing number of cellular compartments and organelles are being implicated in cell death and cancer. Here, we discuss the mitochondria and subdomains of the endoplasmic reticulum (ER) that interact with mitochondria, the mitochondria-associated membranes (MAMs), which have been identified as critical hubs in the regulation of cell death and tumor growth. MAMs-dependent calcium (Ca 2+ ) release from the ER allows selective Ca 2+ uptake by the mitochondria. The perturbation of Ca 2+ homeostasis in cancer cells is correlated with sustained cell proliferation and the inhibition of cell death through the modulation of Ca 2+ signaling. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Glutathione and Mitochondria

    Directory of Open Access Journals (Sweden)

    Vicent eRibas

    2014-07-01

    Full Text Available Glutathione (GSH is the main nonprotein thiol in cells whose functions are dependent on the redox-active thiol of its cysteine moiety that serves as a cofactor for a number of antioxidant and detoxifying enzymes. While synthesized exclusively in the cytosol from its constituent amino acids, GSH is distributed in different compartments, including mitochondria where its concentration in the matrix equals that of the cytosol. This feature and its negative charge at physiological pH imply the existence of specific carriers to import GSH from the cytosol to the mitochondrial matrix, where it plays a key role in defense against respiration-induced reactive oxygen species and in the detoxification of lipid hydroperoxides and electrophiles. Moreover, as mitochondria play a central strategic role in the activation and mode of cell death, mitochondrial GSH has been shown to critically regulate the level of sensitization to secondary hits that induce mitochondrial membrane permeabilization and release of proteins confined in the intermembrane space that once in the cytosol engage the molecular machinery of cell death. In this review, we summarize recent data on the regulation of mitochondrial GSH and its role in cell death and prevalent human diseases, such as cancer, fatty liver disease and Alzheimer’s disease.

  9. Drought occurence

    Science.gov (United States)

    John W. Coulston

    2007-01-01

    Why Is Drought Important? Drought is an important forest disturbance that occurs regularly in the Western United States and irregularly in the Eastern United States (Dale and others 2001). Moderate drought stress tends to slow plant growth while severedrought stress can also reduce photosynthesis (Kareiva and others 1993). Drought can also interact with...

  10. Interorganelle Communication between Mitochondria and the Endolysosomal System

    Directory of Open Access Journals (Sweden)

    Gonzalo Soto-Heredero

    2017-11-01

    Full Text Available The function of mitochondria and lysosomes has classically been studied separately. However, evidence has now emerged of intense crosstalk between these two organelles, such that the activity or stress status of one organelle may affect the other. Direct physical contacts between mitochondria and the endolysosomal compartment have been reported as a rapid means of interorganelle communication, mediating lipid or other metabolite exchange. Moreover, mitochondrial derived vesicles can traffic obsolete mitochondrial proteins into the endolysosomal system for their degradation or secretion to the extracellular milieu as exosomes, representing an additional mitochondrial quality control mechanism that connects mitochondria and lysosomes independently of autophagosome formation. Here, we present what is currently known about the functional and physical communication between mitochondria and lysosomes or lysosome-related organelles, and their role in sustaining cellular homeostasis.

  11. Biochemistry of Mitochondria

    Directory of Open Access Journals (Sweden)

    Filiz Koc

    2003-02-01

    Full Text Available Mitochondria are energy source of cells. They have external and internal membranes, cristas and matrix. External membranes consist of specialized transport proteins. They have monoamine oxidase and citokrome-c reductase which both play role in KREBS cycle as catalyst and many enzymes which are necessary for phospholipid and phosphoric acid synthesis. Enzymes of electron transport chain and oxidative phosphorylation are located in the internal membranes. Also, here, there are transport systems for specific substances, such as ATP, ADP, P1, pyruvate, succinate, malate, citrate, and -ketoglutarate . Matrix; having gel-like consistency, contains a large number of enzymes. [Archives Medical Review Journal 2003; 12(0.100: 1-13

  12. Aging and mitochondria.

    Science.gov (United States)

    Gadaleta, M N; Cormio, A; Pesce, V; Lezza, A M; Cantatore, P

    1998-10-01

    Aging is a complex physiological phenomenon and several different theories have been elaborated about its origin. Among such theories, the 'mitochondrial theory of aging', which has gained a large support, indicates the accumulation of somatic mutations of mitochondrial DNA leading to the decline of mitochondrial functionality as one of the driving forces for the process itself. In this review data on rat and man from our laboratory and from recent literature have been thoroughly examined and compared in order to provide the 'state-of-the-art' on the role of mitochondria in aging. Alterations of structure and expression of mitochondrial genome with aging, to find out the eventual relevant changes of mitochondrial biogenesis, have been studied in rat whereas the relationship between cytochrome c oxidase activity and 'common deletion' has been studied in man. Results on the effect of acetyl-L-carnitine on the mitochondrial functionality are also reported.

  13. Do the mitochondria of malaria parasites behave like the phoenix after return in the mosquito? Regeneration of degenerated mitochondria is required for successful Plasmodium infection.

    Science.gov (United States)

    Bongaerts, Ger

    2005-01-01

    Mitochondria are energy generators in eukaryotic organisms like man and the pathogenic malaria parasites, the Plasmodium spp. From the moment a mosquito-mediated malaria infection occurs in man the parasite multiplies profusely, but eventually the oxygen supply becomes the limiting factor in this process. Consequently, the parasite will increasingly generate energy (and lactic acid) from sugar fermentation. Simultaneously, the cristate structure of Plasmodium mitochondria degenerates and becomes acristate. The degenerated acristate mitochondria of mammalian Plasmodium parasites seem to be able to revitalise by transforming to cristate mitochondria inside the oxygen-rich mosquito, like the rebirth of the old phoenix. In this way the infectivity of the parasite is revitalised.

  14. Mitochondria in health and disease

    DEFF Research Database (Denmark)

    Durhuus, Jon Ambæk; Madsen, Claus Desler; Rasmussen, Lene Juel

    2015-01-01

    The primary role of mitochondria was long considered to be production of cellular energy. However, as the understanding of mitochondria in disease is ever expanding, so is their additional function for a healthy organism. Mitochondrial dysfunction is linked to a range of pathologies, including...... (SMRM) was titled "Mitochondria in Health and Disease". The conference was organized by Gayathri N, K Thangaraj, and KK Singh and was held at the National Institute of Mental Health & Neuro Sciences (NIMHANS) in Bangalore, India, from the 19th to 20th of December 2013. The meeting featured...

  15. Connecting Mitochondria, Metabolism, and Stem Cell Fate

    Science.gov (United States)

    Wanet, Anaïs; Arnould, Thierry; Najimi, Mustapha

    2015-01-01

    As sites of cellular respiration and energy production, mitochondria play a central role in cell metabolism. Cell differentiation is associated with an increase in mitochondrial content and activity and with a metabolic shift toward increased oxidative phosphorylation activity. The opposite occurs during reprogramming of somatic cells into induced pluripotent stem cells. Studies have provided evidence of mitochondrial and metabolic changes during the differentiation of both embryonic and somatic (or adult) stem cells (SSCs), such as hematopoietic stem cells, mesenchymal stem cells, and tissue-specific progenitor cells. We thus propose to consider those mitochondrial and metabolic changes as hallmarks of differentiation processes. We review how mitochondrial biogenesis, dynamics, and function are directly involved in embryonic and SSC differentiation and how metabolic and sensing pathways connect mitochondria and metabolism with cell fate and pluripotency. Understanding the basis of the crosstalk between mitochondria and cell fate is of critical importance, given the promising application of stem cells in regenerative medicine. In addition to the development of novel strategies to improve the in vitro lineage-directed differentiation of stem cells, understanding the molecular basis of this interplay could lead to the identification of novel targets to improve the treatment of degenerative diseases. PMID:26134242

  16. Melatonin, mitochondria and hypertension.

    Science.gov (United States)

    Baltatu, Ovidiu C; Amaral, Fernanda G; Campos, Luciana A; Cipolla-Neto, Jose

    2017-11-01

    Melatonin, due to its multiple means and mechanisms of action, plays a fundamental role in the regulation of the organismal physiology by fine tunning several functions. The cardiovascular system is an important site of action as melatonin regulates blood pressure both by central and peripheral interventions, in addition to its relation with the renin-angiotensin system. Besides, the systemic management of several processes, melatonin acts on mitochondria regulation to maintain a healthy cardiovascular system. Hypertension affects target organs in different ways and cellular energy metabolism is frequently involved due to mitochondrial alterations that include a rise in reactive oxygen species production and an ATP synthesis decrease. The discussion that follows shows the role played by melatonin in the regulation of mitochondrial physiology in several levels of the cardiovascular system, including brain, heart, kidney, blood vessels and, particularly, regulating the renin-angiotensin system. This discussion shows the putative importance of using melatonin as a therapeutic tool involving its antioxidant potential and its action on mitochondrial physiology in the cardiovascular system.

  17. Interaction theory of mammalian mitochondria.

    Science.gov (United States)

    Nakada, K; Inoue, K; Hayashi, J

    2001-11-09

    We generated mice with deletion mutant mtDNA by its introduction from somatic cells into mouse zygotes. Expressions of disease phenotypes are limited to tissues expressing mitochondrial dysfunction. Considering that all these mice share the same nuclear background, these observations suggest that accumulation of the mutant mtDNA and resultant expressions of mitochondrial dysfunction are responsible for expression of disease phenotypes. On the other hand, mitochondrial dysfunction and expression of clinical abnormalities were not observed until the mutant mtDNA accumulated predominantly. This protection is due to the presence of extensive and continuous interaction between exogenous mitochondria from cybrids and recipient mitochondria from embryos. Thus, we would like to propose a new hypothesis on mitochondrial biogenesis, interaction theory of mitochondria: mammalian mitochondria exchange genetic contents, and thus lost the individuality and function as a single dynamic cellular unit. Copyright 2001 Academic Press.

  18. Protonmotive force in muscle mitochondria

    International Nuclear Information System (INIS)

    Stumpf, D.A.; Haas, R.; Eguren, L.A.; Parks, J.K.; Eilert, R.E.

    1982-01-01

    The protonmotive force (delta p) of muscle mitochondria was measured by estimating the distribution of 14C-labeled TPMP (trimethylphenylphosphonium iodide) and 14C-labeled acetate across the inner membrane of muscle mitochondria. The matrix volume was simultaneously determined using 3H-labeled H2O and 3H-labeled mannitol and repeated drying to distinguish the label in these 2 compounds. Rapid separation of mitochondria from the incubation medium by centrifugation through silicone oil avoids the problems of potential anaerobic conditions associated with conventional centrifugation and large volumes of trapped media associated with filtration. The value for delta p (mean +/- SD) was 192+/- 26 mV in 30 determinations with rat muscle mitochondria during state 4. Measurement of oxygen consumption allowed calculation of membrane conductance (Cm,H+) which was 0.49 +/- 0.18 nmol of H+/min/mg protein/mV. The values for delta p and Cm,H+ are reported for a variety of experimental conditions and are consistent with Mitchell's chemiosmotic theory. Biopsy specimens obtained from human muscle gave state-4 delta p values of 197+/- 30 mV (n .5) and Cm,H+ values of 0.52 +/- 0.12 nmol of H+/min/mg/mV (n . 4). This delta p assay is the first described for coupled mammalian muscle mitochondria and will be useful in assessing membrane function

  19. A conserved endoplasmic reticulum membrane protein complex (EMC facilitates phospholipid transfer from the ER to mitochondria.

    Directory of Open Access Journals (Sweden)

    Sujoy Lahiri

    2014-10-01

    Full Text Available Mitochondrial membrane biogenesis and lipid metabolism require phospholipid transfer from the endoplasmic reticulum (ER to mitochondria. Transfer is thought to occur at regions of close contact of these organelles and to be nonvesicular, but the mechanism is not known. Here we used a novel genetic screen in S. cerevisiae to identify mutants with defects in lipid exchange between the ER and mitochondria. We show that a strain missing multiple components of the conserved ER membrane protein complex (EMC has decreased phosphatidylserine (PS transfer from the ER to mitochondria. Mitochondria from this strain have significantly reduced levels of PS and its derivative phosphatidylethanolamine (PE. Cells lacking EMC proteins and the ER-mitochondria tethering complex called ERMES (the ER-mitochondria encounter structure are inviable, suggesting that the EMC also functions as a tether. These defects are corrected by expression of an engineered ER-mitochondrial tethering protein that artificially tethers the ER to mitochondria. EMC mutants have a significant reduction in the amount of ER tethered to mitochondria even though ERMES remained intact in these mutants, suggesting that the EMC performs an additional tethering function to ERMES. We find that all Emc proteins interact with the mitochondrial translocase of the outer membrane (TOM complex protein Tom5 and this interaction is important for PS transfer and cell growth, suggesting that the EMC forms a tether by associating with the TOM complex. Together, our findings support that the EMC tethers ER to mitochondria, which is required for phospholipid synthesis and cell growth.

  20. Immobilization of Mitochondria on Graphene

    Science.gov (United States)

    2013-08-29

    poly-L-lysine has also been reported for immobilization of yeast mitochondria. Coating was performed by repetitive washing of cover slips with 0.02...of Poly-L-lysine Applications of PLL PLL is a production of bacterial fermentation and is used as a food preservative. In biology, PLL is used in

  1. Mitochondria in aging cell differentiation

    Czech Academy of Sciences Publication Activity Database

    Palková, Zdena; Váchová, Libuše

    2016-01-01

    Roč. 8, č. 7 (2016), s. 1287-1288 ISSN 1945-4589 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : mitochondria * cell differentiation * retrograde signaling Subject RIV: EE - Microbiology, Virology Impact factor: 4.867, year: 2016

  2. Exogenous ether lipids predominantly target mitochondria

    DEFF Research Database (Denmark)

    Kuerschner, Lars; Richter, Doris; Hannibal-Bach, Hans Kristian

    2012-01-01

    Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high......, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria...

  3. Skeletal Muscle Estrogen Receptor Activation in Response to Eccentric Exercise Up-Regulates Myogenic-Related Gene Expression Independent of Differing Serum Estradiol Levels Occurring during the Human Menstrual Cycle.

    Science.gov (United States)

    Haines, Mackenzie; McKinley-Barnard, Sarah K; Andre, Thomas L; Gann, Josh J; Hwang, Paul S; Willoughby, Darryn S

    2018-03-01

    This study sought to determine if the differences in serum estradiol we have previously observed to occur during the mid-follicular (MF) and mid-luteal (ML) phases of the female menstrual cycle could be attributed to estrogen-induced receptor activation and subsequent effects on myogenic-related genes which may otherwise impact muscle regeneration in response to eccentric exercise. Twenty-two physically-active females (20.9 ± 1.4 years, 63.5 ± 9.0 kg, 1.65 ± 0.08 m) underwent an eccentric exercise bout of the knee extensors during the MF and ML phases of their 28-day menstrual cycle. Prior to (PRE), at 6 (6HRPOST), and 24 (24HRPOST) hours post-exercise for each session, participants had muscle biopsies obtained. Skeletal muscle estradiol and estrogen receptor-α (ER-α) content and ER-DNA binding were determined with ELISA. Real-time PCR was used to assess ER-α, Myo-D, and cyclin D1 mRNA expression. Data were analyzed utilizing a 2 x 3 repeated measures univariate analyses of variance (ANOVA) for each criterion variable (p ≤ .05). Skeletal muscle estradiol levels were not significantly impacted by either menstrual phase (p > 0.05); however, both ER-α mRNA and protein were significantly increased during MF (p < 0.05). ER-DNA binding and Myo-D mRNA expression increased significantly in both menstrual phases in response to exercise but were not different from one another; however, cyclin D1 mRNA expression was significantly greater during MF. This study demonstrates that skeletal muscle ER-α activation in response to eccentric exercise up-regulates myogenic-related gene expression independent of serum estradiol levels occurring during the human menstrual cycle.

  4. Doubly uniparental inheritance of mitochondria as a model system for studying germ line formation.

    Directory of Open Access Journals (Sweden)

    Liliana Milani

    Full Text Available BACKGROUND: Doubly Uniparental Inheritance (DUI of mitochondria occurs when both mothers and fathers are capable of transmitting mitochondria to their offspring, in contrast to the typical Strictly Maternal Inheritance (SMI. DUI was found in some bivalve molluscs, in which two mitochondrial genomes are inherited, one through eggs, the other through sperm. During male embryo development, spermatozoon mitochondria aggregate in proximity of the first cleavage furrow and end up in the primordial germ cells, while they are dispersed in female embryos. METHODOLOGY/PRINCIPAL FINDINGS: We used MitoTracker, microtubule staining and transmission electron microscopy to examine the mechanisms of this unusual distribution of sperm mitochondria in the DUI species Ruditapes philippinarum. Our results suggest that in male embryos the midbody deriving from the mitotic spindle of the first division concurs in positioning the aggregate of sperm mitochondria. Furthermore, an immunocytochemical analysis showed that the germ line determinant Vasa segregates close to the first cleavage furrow. CONCLUSIONS/SIGNIFICANCE: In DUI male embryos, spermatozoon mitochondria aggregate in a stable area on the animal-vegetal axis: in organisms with spiral segmentation this zone is not involved in cleavage, so the aggregation is maintained. Moreover, sperm mitochondria reach the same embryonic area in which also germ plasm is transferred. In 2-blastomere embryos, the segregation of sperm mitochondria in the same region with Vasa suggests their contribution in male germ line formation. In DUI male embryos, M-type mitochondria must be recognized by egg factors to be actively transferred in the germ line, where they become dominant replacing the Balbiani body mitochondria. The typical features of germ line assembly point to a common biological mechanism shared by DUI and SMI organisms. Although the molecular dynamics of the segregation of sperm mitochondria in DUI species are unknown

  5. Fe-S Cluster Biogenesis in Isolated Mammalian Mitochondria

    Science.gov (United States)

    Pandey, Alok; Pain, Jayashree; Ghosh, Arnab K.; Dancis, Andrew; Pain, Debkumar

    2015-01-01

    Iron-sulfur (Fe-S) clusters are essential cofactors, and mitochondria contain several Fe-S proteins, including the [4Fe-4S] protein aconitase and the [2Fe-2S] protein ferredoxin. Fe-S cluster assembly of these proteins occurs within mitochondria. Although considerable data exist for yeast mitochondria, this biosynthetic process has never been directly demonstrated in mammalian mitochondria. Using [35S]cysteine as the source of sulfur, here we show that mitochondria isolated from Cath.A-derived cells, a murine neuronal cell line, can synthesize and insert new Fe-35S clusters into aconitase and ferredoxins. The process requires GTP, NADH, ATP, and iron, and hydrolysis of both GTP and ATP is necessary. Importantly, we have identified the 35S-labeled persulfide on the NFS1 cysteine desulfurase as a genuine intermediate en route to Fe-S cluster synthesis. In physiological settings, the persulfide sulfur is released from NFS1 and transferred to a scaffold protein, where it combines with iron to form an Fe-S cluster intermediate. We found that the release of persulfide sulfur from NFS1 requires iron, showing that the use of iron and sulfur for the synthesis of Fe-S cluster intermediates is a highly coordinated process. The release of persulfide sulfur also requires GTP and NADH, probably mediated by a GTPase and a reductase, respectively. ATP, a cofactor for a multifunctional Hsp70 chaperone, is not required at this step. The experimental system described here may help to define the biochemical basis of diseases that are associated with impaired Fe-S cluster biogenesis in mitochondria, such as Friedreich ataxia. PMID:25398879

  6. Nitric oxide and mitochondria in metabolic syndrome

    Science.gov (United States)

    Litvinova, Larisa; Atochin, Dmitriy N.; Fattakhov, Nikolai; Vasilenko, Mariia; Zatolokin, Pavel; Kirienkova, Elena

    2015-01-01

    Metabolic syndrome (MS) is a cluster of metabolic disorders that collectively increase the risk of cardiovascular disease. Nitric oxide (NO) plays a crucial role in the pathogeneses of MS components and is involved in different mitochondrial signaling pathways that control respiration and apoptosis. The present review summarizes the recent information regarding the interrelations of mitochondria and NO in MS. Changes in the activities of different NO synthase isoforms lead to the formation of metabolic disorders and therefore are highlighted here. Reduced endothelial NOS activity and NO bioavailability, as the main factors underlying the endothelial dysfunction that occurs in MS, are discussed in this review in relation to mitochondrial dysfunction. We also focus on potential therapeutic strategies involving NO signaling pathways that can be used to treat patients with metabolic disorders associated with mitochondrial dysfunction. The article may help researchers develop new approaches for the diagnosis, prevention and treatment of MS. PMID:25741283

  7. Apoptosis in Drosophila: which role for mitochondria?

    Science.gov (United States)

    Clavier, Amandine; Rincheval-Arnold, Aurore; Colin, Jessie; Mignotte, Bernard; Guénal, Isabelle

    2016-03-01

    It is now well established that the mitochondrion is a central regulator of mammalian cell apoptosis. However, the importance of this organelle in non-mammalian apoptosis has long been regarded as minor, mainly because of the absence of a crucial role for cytochrome c in caspase activation. Recent results indicate that the control of caspase activation and cell death in Drosophila occurs at the mitochondrial level. Numerous proteins, including RHG proteins and proteins of the Bcl-2 family that are key regulators of Drosophila apoptosis, constitutively or transiently localize in mitochondria. These proteins participate in the cell death process at different levels such as degradation of Diap1, a Drosophila IAP, production of mitochondrial reactive oxygen species or stimulation of the mitochondrial fission machinery. Here, we review these mitochondrial events that might have their counterpart in human.

  8. [Mitochondria inheritance in yeast saccharomyces cerevisiae].

    Science.gov (United States)

    Fizikova, A Iu

    2011-01-01

    The review is devoted to the main mechanisms of mitochondria inheritance in yeast Saccharonmyces cerevisiae. The genetic mechanisms of functionally active mitochondria inheritance in eukaryotic cells is one of the most relevant in modem researches. A great number of genetic diseases are associated with mitochondria dysfunction. Plasticity of eukaryotic cell metabolism according to the environmental changes is ensured by adequate mitochondria functioning by means of ATP synthesis coordination, reactive oxygen species accumulation, apoptosis regulation and is an important factor of cell adaptation to stress. Mitochondria participation in important for cell vitality processes masters the presence of accurate mechanisms of mitochondria functions regulation according to environment fluctuations. The mechanisms of mitochondria division and distribution are highly conserved. Baker yeast S. cerevisiae is an ideal model object for mitochondria researches due to energetic metabolism lability, ability to switch over respiration to fermentation, and petite-positive phenotype. Correction of metabolism according to the environmental changes is necessary for cell vitality. The influence of respiratory, carbon, amino acid and phosphate metabolism on mitochondria functions was shown. As far as the mechanisms that stabilize functions of mitochondria and mtDNA are highly conserve, we can project yeast regularities on higher eukaryotes systems. This makes it possible to approximate understanding the etiology and pathogenesis of a great number of human diseases.

  9. Mitochondria and Neurotransmission: Evacuating the Synapse

    OpenAIRE

    Hollenbeck, Peter J.

    2005-01-01

    An abundance of mitochondria has been the hallmark of synapses since their first ultrastructural description 50 years ago. Mitochondria have been shown to be essential for synaptic form and function in many systems, but until recently it has not been clear exactly what role(s) they play in neurotransmission. Now, evidence from the nervous system of Drosophila identifies the specific subcellular events that are most dependent upon nearby mitochondria.

  10. Mitochondria in biology and medicine

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Rasmussen, Lene Juel

    2012-01-01

    pathologies (Luft, 1994). Since 1959, the understanding of mitochondrial cytopathies has evolved immensely and mitochondrial cytopathies are now known to be the largest group of metabolic diseases and to be resulting in a wide variety of pathologies. "Mitochondria in Biology and Medicine" was the title...... of the first annual conference of Society of Mitochondrial Research and Medicine - India. The conference was organized by A. S. Sreedhar, Keshav Singh and Kumarasamy Thangaraj, and was held at The Centre for Cellular and Molecular Biology (CCMB) Hyderabad, India, during 9-10 December 2011. The conference...

  11. Dynamic survey of mitochondria by ubiquitin

    Science.gov (United States)

    Escobar-Henriques, Mafalda; Langer, Thomas

    2014-01-01

    Ubiquitin is a post-translational modifier with proteolytic and non-proteolytic roles in many biological processes. At mitochondria, it performs regulatory homeostatic functions and contributes to mitochondrial quality control. Ubiquitin is essential for mitochondrial fusion, regulates mitochondria-ER contacts, and participates in maternal mtDNA inheritance. Under stress, mitochondrial dysfunction induces ubiquitin-dependent responses that involve mitochondrial proteome remodeling and culminate in organelle removal by mitophagy. In addition, many ubiquitin-dependent mechanisms have been shown to regulate innate immune responses and xenophagy. Here, we review the emerging roles of ubiquitin at mitochondria. PMID:24569520

  12. Melatonin, mitochondria, and the skin.

    Science.gov (United States)

    Slominski, Andrzej T; Zmijewski, Michal A; Semak, Igor; Kim, Tae-Kang; Janjetovic, Zorica; Slominski, Radomir M; Zmijewski, Jaroslaw W

    2017-11-01

    The skin being a protective barrier between external and internal (body) environments has the sensory and adaptive capacity to maintain local and global body homeostasis in response to noxious factors. An important part of the skin response to stress is its ability for melatonin synthesis and subsequent metabolism through the indolic and kynuric pathways. Indeed, melatonin and its metabolites have emerged as indispensable for physiological skin functions and for effective protection of a cutaneous homeostasis from hostile environmental factors. Moreover, they attenuate the pathological processes including carcinogenesis and other hyperproliferative/inflammatory conditions. Interestingly, mitochondria appear to be a central hub of melatonin metabolism in the skin cells. Furthermore, substantial evidence has accumulated on the protective role of the melatonin against ultraviolet radiation and the attendant mitochondrial dysfunction. Melatonin and its metabolites appear to have a modulatory impact on mitochondrion redox and bioenergetic homeostasis, as well as the anti-apoptotic effects. Of note, some metabolites exhibit even greater impact than melatonin alone. Herein, we emphasize that melatonin-mitochondria axis would control integumental functions designed to protect local and perhaps global homeostasis. Given the phylogenetic origin and primordial actions of melatonin, we propose that the melatonin-related mitochondrial functions represent an evolutionary conserved mechanism involved in cellular adaptive response to skin injury and repair.

  13. RNA Editing in Plant Mitochondria

    Science.gov (United States)

    Hiesel, Rudolf; Wissinger, Bernd; Schuster, Wolfgang; Brennicke, Axel

    1989-12-01

    Comparative sequence analysis of genomic and complementary DNA clones from several mitochondrial genes in the higher plant Oenothera revealed nucleotide sequence divergences between the genomic and the messenger RNA-derived sequences. These sequence alterations could be most easily explained by specific post-transcriptional nucleotide modifications. Most of the nucleotide exchanges in coding regions lead to altered codons in the mRNA that specify amino acids better conserved in evolution than those encoded by the genomic DNA. Several instances show that the genomic arginine codon CGG is edited in the mRNA to the tryptophan codon TGG in amino acid positions that are highly conserved as tryptophan in the homologous proteins of other species. This editing suggests that the standard genetic code is used in plant mitochondria and resolves the frequent coincidence of CGG codons and tryptophan in different plant species. The apparently frequent and non-species-specific equivalency of CGG and TGG codons in particular suggests that RNA editing is a common feature of all higher plant mitochondria.

  14. The role of uncoupling protein 3 regulating calcium ion uptake into mitochondria during sarcopenia

    Science.gov (United States)

    Nikawa, Takeshi; Choi, Inho; Haruna, Marie; Hirasaka, Katsuya; Maita Ohno, Ayako; Kondo Teshima, Shigetada

    Overloaded mitochondrial calcium concentration contributes to progression of mitochondrial dysfunction in aged muscle, leading to sarcopenia. Uncoupling protein 3 (UCP3) is primarily expressed in the inner membrane of skeletal muscle mitochondria. Recently, it has been reported that UCP3 is associated with calcium uptake into mitochondria. However, the mechanisms by which UCP3 regulates mitochondrial calcium uptake are not well understood. Here we report that UCP3 interacts with HS-1 associated protein X-1 (Hax-1), an anti-apoptotic protein that is localized in mitochondria, which is involved in cellular responses to calcium ion. The hydrophilic sequences within the loop 2, matrix-localized hydrophilic domain of mouse UCP3 are necessary for binding to Hax-1 of the C-terminal domain in adjacent to mitochondrial innermembrane. Interestingly, these proteins interaction occur the calcium-dependent manner. Indeed, overexpression of UCP3 significantly enhanced calcium uptake into mitochondria on Hax-1 endogenously expressing C2C12 myoblasts. In addition, Hax-1 knock-down enhanced calcium uptake into mitochondria on both UCP3 and Hax-1 endogenously expressing C2C12 myotubes, but not myoblasts. Finally, the dissociation of UCP3 and Hax-1 enhances calcium uptake into mitochondria in aged muscle. These studies identify a novel UCP3-Hax-1 complex regulates the influx of calcium ion into mitochondria in muscle. Thus, the efficacy of UCP3-Hax-1 in mitochondrial calcium regulation may provide a novel therapeutic approach against mitochondrial dysfunction-related disease containing sarcopenia.

  15. Your mitochondria are what you eat

    DEFF Research Database (Denmark)

    Jørgensen, Wenche; Rud, Kasper Abildgaard; Mortensen, Ole Hartvig

    2017-01-01

    of the mitochondria. Here, we report that rat muscle mitochondria does show the normal Randle‐type fat‐carbohydrate interaction seen in vivo. The mechanism behind this metabolic flexibility at the level of the isolated mitochondria is a regulation of the flux‐ratio: pyruvate dehydrogenase (PDH)/β‐oxidation to suit...... the actual substrate availability, with the PDH flux as the major point of regulation. We further report that this regulatory mechanism of carbohydrate‐fat metabolic interaction surprisingly is lost in mitochondria obtained from animals exposed for 12 weeks to a HF‐ or a HS diet as compared to rats given...... a normal chow diet. The mechanism seems to be a loss of the PDH flux decrease seen in controls, when fatty acid is supplied as substrate in addition to pyruvate, and vice versa for the supply of pyruvate as substrate to mitochondria oxidizing fatty acid. Finally, we report that the calculated TCA flux...

  16. Potassium channels in brain mitochondria.

    Science.gov (United States)

    Bednarczyk, Piotr

    2009-01-01

    Potassium channels are the most widely distributed class of ion channels. These channels are transmembrane proteins known to play important roles in both normal and pathophysiological functions in all cell types. Various potassium channels are recognised as potential therapeutic targets in the treatment of Parkinson's disease, Alzheimer's disease, brain/spinal cord ischaemia and sepsis. In addition to their importance as therapeutic targets, certain potassium channels are known for their beneficial roles in anaesthesia, cardioprotection and neuroprotection. Some types of potassium channels present in the plasma membrane of various cells have been found in the inner mitochondrial membrane as well. Potassium channels have been proposed to regulate mitochondrial membrane potential, respiration, matrix volume and Ca(+) ion homeostasis. It has been proposed that mitochondrial potassium channels mediate ischaemic preconditioning in various tissues. However, the specificity of a pharmacological agents and the mechanisms underlying their effects on ischaemic preconditioning remain controversial. The following potassium channels from various tissues have been identified in the inner mitochondrial membrane: ATP-regulated (mitoK(ATP)) channel, large conductance Ca(2+)-regulated (mitoBK(Ca)) channel, intermediate conductance Ca(2+)-regulated (mitoIK(Ca)) channel, voltage-gated (mitoKv1.3 type) channel, and twin-pore domain (mitoTASK-3) channel. It has been shown that increased potassium flux into brain mitochondria induced by either the mitoK(ATP) channel or mitoBK(Ca) channel affects the beneficial effects on neuronal cell survival under pathological conditions. Recently, differential distribution of mitoBK(Ca) channels has been observed in neuronal mitochondria. These findings may suggest a neuroprotective role for the mitoBK(Ca) channel in specific brain structures. This minireview summarises current data on brain mitochondrial potassium channels and the efforts to identify

  17. Parkin suppresses Drp1-independent mitochondrial division

    International Nuclear Information System (INIS)

    Roy, Madhuparna; Itoh, Kie; Iijima, Miho; Sesaki, Hiromi

    2016-01-01

    The cycle of mitochondrial division and fusion disconnect and reconnect individual mitochondria in cells to remodel this energy-producing organelle. Although dynamin-related protein 1 (Drp1) plays a major role in mitochondrial division in cells, a reduced level of mitochondrial division still persists even in the absence of Drp1. It is unknown how much Drp1-mediated mitochondrial division accounts for the connectivity of mitochondria. The role of a Parkinson’s disease-associated protein—parkin, which biochemically and genetically interacts with Drp1—in mitochondrial connectivity also remains poorly understood. Here, we quantified the number and connectivity of mitochondria using mitochondria-targeted photoactivatable GFP in cells. We show that the loss of Drp1 increases the connectivity of mitochondria by 15-fold in mouse embryonic fibroblasts (MEFs). While a single loss of parkin does not affect the connectivity of mitochondria, the connectivity of mitochondria significantly decreased compared with a single loss of Drp1 when parkin was lost in the absence of Drp1. Furthermore, the loss of parkin decreased the frequency of depolarization of the mitochondrial inner membrane that is caused by increased mitochondrial connectivity in Drp1-knockout MEFs. Therefore, our data suggest that parkin negatively regulates Drp1-indendent mitochondrial division. -- Highlights: •A Drp1-mediated mechanism accounts for ∼95% of mitochondrial division. •Parkin controls the connectivity of mitochondria via a mechanism that is independent of Drp1. •In the absence of Drp1, connected mitochondria transiently depolarize. •The transient depolarization is independent of calcium signaling and uncoupling protein 2.

  18. Parkin suppresses Drp1-independent mitochondrial division

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Madhuparna, E-mail: mroy17@jhmi.edu; Itoh, Kie, E-mail: kito5@jhmi.edu; Iijima, Miho, E-mail: miijima@jhmi.edu; Sesaki, Hiromi, E-mail: hsesaki@jhmi.edu

    2016-07-01

    The cycle of mitochondrial division and fusion disconnect and reconnect individual mitochondria in cells to remodel this energy-producing organelle. Although dynamin-related protein 1 (Drp1) plays a major role in mitochondrial division in cells, a reduced level of mitochondrial division still persists even in the absence of Drp1. It is unknown how much Drp1-mediated mitochondrial division accounts for the connectivity of mitochondria. The role of a Parkinson’s disease-associated protein—parkin, which biochemically and genetically interacts with Drp1—in mitochondrial connectivity also remains poorly understood. Here, we quantified the number and connectivity of mitochondria using mitochondria-targeted photoactivatable GFP in cells. We show that the loss of Drp1 increases the connectivity of mitochondria by 15-fold in mouse embryonic fibroblasts (MEFs). While a single loss of parkin does not affect the connectivity of mitochondria, the connectivity of mitochondria significantly decreased compared with a single loss of Drp1 when parkin was lost in the absence of Drp1. Furthermore, the loss of parkin decreased the frequency of depolarization of the mitochondrial inner membrane that is caused by increased mitochondrial connectivity in Drp1-knockout MEFs. Therefore, our data suggest that parkin negatively regulates Drp1-indendent mitochondrial division. -- Highlights: •A Drp1-mediated mechanism accounts for ∼95% of mitochondrial division. •Parkin controls the connectivity of mitochondria via a mechanism that is independent of Drp1. •In the absence of Drp1, connected mitochondria transiently depolarize. •The transient depolarization is independent of calcium signaling and uncoupling protein 2.

  19. Mitochondria: role of citrulline and arginine supplementation in MELAS syndrome.

    Science.gov (United States)

    El-Hattab, Ayman W; Emrick, Lisa T; Chanprasert, Sirisak; Craigen, William J; Scaglia, Fernando

    2014-03-01

    Mitochondria are found in all nucleated human cells and generate most of the cellular energy. Mitochondrial disorders result from dysfunctional mitochondria that are unable to generate sufficient ATP to meet the energy needs of various organs. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a frequent maternally inherited mitochondrial disorder. There is growing evidence that nitric oxide (NO) deficiency occurs in MELAS syndrome and results in impaired blood perfusion that contributes significantly to several complications including stroke-like episodes, myopathy, and lactic acidosis. Both arginine and citrulline act as NO precursors and their administration results in increased NO production and hence can potentially have therapeutic utility in MELAS syndrome. Citrulline raises NO production to a greater extent than arginine, therefore, citrulline may have a better therapeutic effect. Controlled studies assessing the effects of arginine or citrulline supplementation on different clinical aspects of MELAS syndrome are needed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. An alternative membrane transport pathway for phosphate and adenine nucleotides in mitochondria and its possible function

    Science.gov (United States)

    Reynafarje, Baltazar; Lehninger, Albert L.

    1978-01-01

    This paper describes the properties and a possible biological role of a transport process across the inner membrane of rat liver mitochondria resulting in the exchange of ATP4- (out) for ADP3- (in) + 0.5 phosphate2- (in). This transmembrane exchange reaction, designated as the ATP-ADP-phosphate exchange, is specific for the ligands shown, electroneutral, insensitive to N-ethylmaleimide or mersalyl, inhibited by atractyloside, and appears to occur only in the direction as written. It is thus distinct from the well-known phosphate-hydroxide and phosphate-dicarboxylate exchange systems, which are inhibited by mersalyl, and from the ATP-ADP exchanger, which does not transport phosphate. During ATP hydrolysis by mitochondria, half of the phosphate formed from ATP passes from the matrix to the medium by the mersalyl-insensitive ATP-ADP-phosphate exchange and the other half by the well-known mersalyl-sensitive phosphate-hydroxide exchange. These and other considerations have led to a hypothesis for the pathway and stoichiometry of ATP-dependent reverse electron transport, characterized by a requirement of 1.33 molecules of ATP per pair of electrons reversed and by the utilization of a different membrane transport pathway for phosphate and adenine nucleotides than is taken in forward electron flow and oxidative phosphorylation. The possible occurrence of independent pathways for ATP-forming forward electron flow and ATP-consuming reverse electron flow is consonant with the fact that the opposing degradative and synthetic pathways in the central routes of cell metabolism generally have different pathways that are independently regulated. PMID:283393

  1. Peroxisome-mitochondria interplay and disease.

    Science.gov (United States)

    Schrader, Michael; Costello, Joseph; Godinho, Luis F; Islinger, Markus

    2015-07-01

    Peroxisomes and mitochondria are ubiquitous, highly dynamic organelles with an oxidative type of metabolism in eukaryotic cells. Over the years, substantial evidence has been provided that peroxisomes and mitochondria exhibit a close functional interplay which impacts on human health and development. The so-called "peroxisome-mitochondria connection" includes metabolic cooperation in the degradation of fatty acids, a redox-sensitive relationship, an overlap in key components of the membrane fission machineries and cooperation in anti-viral signalling and defence. Furthermore, combined peroxisome-mitochondria disorders with defects in organelle division have been revealed. In this review, we present the latest progress in the emerging field of peroxisomal and mitochondrial interplay in mammals with a particular emphasis on cooperative fatty acid β-oxidation, redox interplay, organelle dynamics, cooperation in anti-viral signalling and the resulting implications for disease.

  2. Mechanisms of communication between mitochondria and lysosomes.

    Science.gov (United States)

    Raimundo, Nuno; Fernández-Mosquera, Lorena; Yambire, King Faisal; Diogo, Cátia V

    2016-10-01

    Mitochondria and lysosomes have long been studied in the context of their classic functions: energy factory and recycle bin, respectively. In the last twenty years, it became evident that these organelles are much more than simple industrial units, and are indeed in charge of many of cellular processes. Both mitochondria and lysosomes are now recognized as far-reaching signaling platforms, regulating many key aspects of cell and tissue physiology. It has furthermore become clear that mitochondria and lysosomes impact each other. The mechanisms underlying the cross-talk between these organelles are only now starting to be addressed. In this review, we briefly summarize how mitochondria, lysosomes and the lysosome-related process of autophagy affect each other in physiology and pathology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Isolation of Mitochondria from Potato Tubers

    DEFF Research Database (Denmark)

    Havelund, Jesper F.; Salvato, Fernanda; Chen, Mingjie

    2014-01-01

    One way to study the function of plant mitochondria is to extract them from plant tissues in an uncontaminated, intact and functional form. The reductionist assumption is that the components present in such a preparation and the in vitro measurable functions or activities reliably reflect...... the in vivo properties of the organelle inside the plant cell. Here, we describe a method to isolate mitochondria from a relatively homogeneous plant tissue, the dormant potato tuber. The homogenization is done using a juice extractor, which is a relatively gentle homogenization procedure where...... the mitochondria are only exposed to strong shearing forces once. After removal of starch and large tissue pieces by filtration, differential centrifugation is used to remove residual starch as well as larger organelles. The crude mitochondria are then first purified by using a step Percoll gradient...

  4. Exogenous ether lipids predominantly target mitochondria.

    Directory of Open Access Journals (Sweden)

    Lars Kuerschner

    Full Text Available Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid tagging. Polyfosine, a fluorescent analogue of the anti-neoplastic ether lipid edelfosine, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria in ether lipid metabolism and intracellular ether lipid trafficking.

  5. Mitochondria-meditated pathways of organ failure upon inflammation

    Directory of Open Access Journals (Sweden)

    Andrey V. Kozlov

    2017-10-01

    Full Text Available Liver failure induced by systemic inflammatory response (SIRS is often associated with mitochondrial dysfunction but the mechanism linking SIRS and mitochondria-mediated liver failure is still a matter of discussion. Current hypotheses suggest that causative events could be a drop in ATP synthesis, opening of mitochondrial permeability transition pore, specific changes in mitochondrial morphology, impaired Ca2+ uptake, generation of mitochondrial reactive oxygen species (mtROS, turnover of mitochondria and imbalance in electron supply to the respiratory chain. The aim of this review is to critically analyze existing hypotheses, in order to highlight the most promising research lines helping to prevent liver failure induced by SIRS. Evaluation of the literature shows that there is no consistent support that impaired Ca++ metabolism, electron transport chain function and ultrastructure of mitochondria substantially contribute to liver failure. Moreover, our analysis suggests that the drop in ATP levels has protective rather than a deleterious character. Recent data suggest that the most critical mitochondrial event occurring upon SIRS is the release of mtROS in cytoplasm, which can activate two specific intracellular signaling cascades. The first is the mtROS-mediated activation of NADPH-oxidase in liver macrophages and endothelial cells; the second is the acceleration of the expression of inflammatory genes in hepatocytes. The signaling action of mtROS is strictly controlled in mitochondria at three points, (i at the site of ROS generation at complex I, (ii the site of mtROS release in cytoplasm via permeability transition pore, and (iii interaction with specific kinases in cytoplasm. The systems controlling mtROS-signaling include pro- and anti-inflammatory mediators, nitric oxide, Ca2+ and NADPH-oxidase. Analysis of the literature suggests that further research should be focused on the impact of mtROS on organ failure induced by inflammation

  6. Heat Shock Protein HSP27 Secretion by Ovarian Cancer Cells Is Linked to Intracellular Expression Levels, Occurs Independently of the Endoplasmic Reticulum Pathway and HSP27’s Phosphorylation Status, and Is Mediated by Exosome Liberation

    Directory of Open Access Journals (Sweden)

    Matthias B. Stope

    2017-01-01

    Full Text Available The heat shock protein HSP27 has been correlated in ovarian cancer (OC patients with aggressiveness and chemoresistance and, therefore, represents a promising potential biomarker for OC diagnosis, prognosis, and treatment response. Notably, secretion of soluble HSP27 has been described by a few cell types and may take place as well in OC cells. Therefore, we studied HSP27 secretion mechanisms under diverse cellular conditions in an OC cell model system. Secretion of HSP27 was characterized after overexpression of HSP27 by transfected plasmids and after heat shock. Intra- and extracellular HSP27 amounts were assessed by Western blotting and ELISA. Protein secretion was blocked by brefeldin A and the impact of the HSP27 phosphorylation status was analyzed overexpressing HSP27 phosphomutants. The present study demonstrated that HSP27 secretion by OVCAR-3 and SK-OV-3 cells depends on intracellular HSP27 concentrations. Moreover, HSP27 secretion is independent of the endoplasmic reticulum secretory pathway and HSP27 phosphorylation. Notably, analysis of OC cell-born exosomes not only confirmed the concentration-dependent correlation of HSP27 expression and secretion but also demonstrated a concentration-dependent incorporation of HSP27 protein into exosomes. Thus, secreted HSP27 may become more important as an extracellular factor which controls the tumor microenvironment and might be a noninvasive biomarker.

  7. Do the mitochondria of malaria parasites behave like the phoenix after return in the mosquito? Regeneration of degenerated mitochondria is required for successful Plasmodium infection.

    NARCIS (Netherlands)

    Bongaerts, G.P.A.

    2005-01-01

    Mitochondria are energy generators in eukaryotic organisms like man and the pathogenic malaria parasites, the Plasmodium spp. From the moment a mosquito-mediated malaria infection occurs in man the parasite multiplies profusely, but eventually the oxygen supply becomes the limiting factor in this

  8. Photothermal imaging of skeletal muscle mitochondria.

    Science.gov (United States)

    Tomimatsu, Toru; Miyazaki, Jun; Kano, Yutaka; Kobayashi, Takayoshi

    2017-06-01

    The morphology and topology of mitochondria provide useful information about the physiological function of skeletal muscle. Previous studies of skeletal muscle mitochondria are based on observation with transmission, scanning electron microscopy or fluorescence microscopy. In contrast, photothermal (PT) microscopy has advantages over the above commonly used microscopic techniques because of no requirement for complex sample preparation by fixation or fluorescent-dye staining. Here, we employed the PT technique using a simple diode laser to visualize skeletal muscle mitochondria in unstained and stained tissues. The fine mitochondrial network structures in muscle fibers could be imaged with the PT imaging system, even in unstained tissues. PT imaging of tissues stained with toluidine blue revealed the structures of subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria and the swelling behavior of mitochondria in damaged muscle fibers with sufficient image quality. PT image analyses based on fast Fourier transform (FFT) and Grey-level co-occurrence matrix (GLCM) were performed to derive the characteristic size of mitochondria and to discriminate the image patterns of normal and damaged fibers.

  9. Neuroprotection by inhibiting the c-Jun N-terminal kinase pathway after cerebral ischemia occurs independently of interleukin-6 and keratinocyte-derived chemokine (KC/CXCL1 secretion

    Directory of Open Access Journals (Sweden)

    Benakis Corinne

    2012-04-01

    Full Text Available Abstract Background Cerebral ischemia is associated with the activation of glial cells, infiltration of leukocytes and an increase in inflammatory mediators in the ischemic brain and systemic circulation. How this inflammatory response influences lesion size and neurological outcome remains unclear. D-JNKI1, an inhibitor of the c-Jun N-terminal kinase pathway, is strongly neuroprotective in animal models of stroke. Intriguingly, the protection mediated by D-JNKI1 is high even with intravenous administration at very low doses with undetectable drug levels in the brain, pointing to a systemic mode of action, perhaps on inflammation. Findings We evaluated whether D-JNKI1, administered intravenously 3 h after the onset of middle cerebral artery occlusion (MCAO, modulates secretion of the inflammatory mediators interleukin-6 and keratinocyte-derived chemokine in the plasma and from the spleen and brain at several time points after MCAO. We found an early release of both mediators in the systemic circulation followed by an increase in the brain and went on to show a later systemic increase in vehicle-treated mice. Release of interleukin-6 and keratinocyte-derived chemokine from the spleen of mice with MCAO was not significantly different from sham mice. Interestingly, the secretion of these inflammatory mediators was not altered in the systemic circulation or brain after successful neuroprotection with D-JNKI1. Conclusions We demonstrate that neuroprotection with D-JNKI1 after experimental cerebral ischemia is independent of systemic and brain release of interleukin-6 and keratinocyte-derived chemokine. Furthermore, our findings suggest that the early systemic release of interleukin-6 and keratinocyte-derived chemokine may not necessarily predict an unfavorable outcome in this model.

  10. A deficiency of apoptosis inducing factor (AIF in Harlequin mouse heart mitochondria paradoxically reduces ROS generation during ischemia-reperfusion

    Directory of Open Access Journals (Sweden)

    Qun eChen

    2014-07-01

    Full Text Available Background and Aims: AIF (apoptosis inducing factor is a flavin and NADH containing protein located within mitochondria required for optimal function of the respiratory chain. AIF may function as an antioxidant within mitochondria, yet when released from mitochondria it activates caspase-independent cell death. The Harlequin (Hq mouse has a markedly reduced content of AIF, providing an experimental model to query if the main role of AIF in the exacerbation of cell death is enhanced mitochondrial generation of reactive oxygen species (ROS or the activation of cell death programs. We asked if the ROS generation is altered in Hq heart mitochondria at baseline or following ischemia-reperfusion (IR.Methods: Buffer perfused mouse hearts underwent 30 min ischemia and 30 min reperfusion. Mitochondrial function including oxidative phosphorylation and H2O2 generation was measured. Immunoblotting was used to determine the contents of AIF and PAR [poly(ADP-ribose] in cell fractions.Results: There were no differences in the release of H2O2 between wild type (WT and Hq heart mitochondria at baseline. IR increased H2O2 generation from WT but not from Hq mitochondria compared to corresponding time controls. The complex I activity was decreased in WT but not in Hq mice following IR. The relocation of AIF from mitochondria to nucleus was increased in WT but not in Hq mice. IR activated PARP-1 only in WT mice. Cell injury was decreased in Hq mouse heart following in vitro IR.Conclusion: A deficiency of AIF within mitochondria does not increase ROS production during IR, indicating that AIF functions less as an antioxidant within mitochondria. The decreased cardiac injury in Hq mouse heart accompanied by less AIF translocation to the nucleus suggests that AIF relocation, rather than the AIF content within mitochondria, contributes to cardiac injury during IR.

  11. Betulinic acid-induced mitochondria-dependent cell death is counterbalanced by an autophagic salvage response

    NARCIS (Netherlands)

    Potze, L.; Mullauer, F. B.; Colak, S.; Kessler, J. H.; Medema, J. P.

    2014-01-01

    Betulinic acid (BetA) is a plant-derived pentacyclic triterpenoid that exerts potent anti-cancer effects in vitro and in vivo. It was shown to induce apoptosis via a direct effect on mitochondria. This is largely independent of proapoptotic BAK and BAX, but can be inhibited by cyclosporin A (CsA),

  12. Co-Occurring Disorders

    Science.gov (United States)

    ... the mental health field. Alcohol and Drug Abuse, Addiction and Co-occurring Disorders: Co-occurring Disorders and ... 500 Montgomery Street, Suite 820 Alexandria, VA 22314 Phone (703) 684.7722 Toll Free (800) 969.6642 ...

  13. Nicotine facilitates nicotinic acetylcholine receptor targeting to mitochondria but makes them less susceptible to selective ligands.

    Science.gov (United States)

    Uspenska, Kateryna; Lykhmus, Olena; Gergalova, Galyna; Chernyshov, Volodymyr; Arias, Hugo R; Komisarenko, Sergiy; Skok, Maryna

    2017-08-24

    Several nicotinic acetylcholine receptor (nAChR) subtypes are expressed in mitochondria to regulate the internal pathway of apoptosis in ion channel-independent manner. However, the mechanisms of nAChR activation in mitochondria and targeting to mitochondria are still unknown. Nicotine has been shown to favor nAChR pentamer assembly, folding, and maturation on the way of biosynthesis. The idea of the present work was to determine whether nicotine affects the content, glycosylation, and function of mitochondrial nAChRs. Experiments were performed in isolated liver mitochondria from mice, that either consumed or not nicotine with the drinking water (200μL/L) for 7days. Mitochondria detergent lysates were studied by sandwich or lectin ELISA for the presence and carbohydrate composition of different nAChR subunits. Intact mitochondria were examined by flow cytometry for the binding of fluorescently labeled α-cobratoxin and were tested in functional assay of cytochrome c release under the effect of either Ca 2+ or wortmannin in the presence or absence of nAChR-selective ligands, including PNU-282987 (1nM), dihydro-β-erythroidine (DhβE, 1μM), PNU-120596 (0.3, 3, or 10μM) and desformylflustrabromine hydrochloride (dFBr, 0.001, 0.3, or 1μM). It was found that nicotine consumption increased the ratio of mitochondrial vs non-mitochondrial nAChRs in the liver, enhanced fucosylation of mitochondrial nAChRs, but prevented the binding of α-cobratoxin and the cytochrome c release-attenuating effects of nAChR-specific agonists, antagonists, or positive allosteric modulators. It is concluded that nicotine consumption in vivo favors nAChR glycosylation and trafficking to mitochondria but makes them less susceptible to the effects of specific ligands. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. An analysis of the effects of Mn2+ on oxidative phosphorylation in liver, brain, and heart mitochondria using state 3 oxidation rate assays

    International Nuclear Information System (INIS)

    Gunter, Thomas E.; Gerstner, Brent; Lester, Tobias; Wojtovich, Andrew P.; Malecki, Jon; Swarts, Steven G.; Brookes, Paul S.; Gavin, Claire E.; Gunter, Karlene K.

    2010-01-01

    Manganese (Mn) toxicity is partially mediated by reduced ATP production. We have used oxidation rate assays-a measure of ATP production-under rapid phosphorylation conditions to explore sites of Mn 2+ inhibition of ATP production in isolated liver, brain, and heart mitochondria. This approach has several advantages. First, the target tissue for Mn toxicity in the basal ganglia is energetically active and should be studied under rapid phosphorylation conditions. Second, Mn may inhibit metabolic steps which do not affect ATP production rate. This approach allows identification of inhibitions that decrease this rate. Third, mitochondria from different tissues contain different amounts of the components of the metabolic pathways potentially resulting in different patterns of ATP inhibition. Our results indicate that Mn 2+ inhibits ATP production with very different patterns in liver, brain, and heart mitochondria. The primary Mn 2+ inhibition site in liver and heart mitochondria, but not in brain mitochondria, is the F 1 F 0 ATP synthase. In mitochondria fueled by either succinate or glutamate + malate, ATP production is much more strongly inhibited in brain than in liver or heart mitochondria; moreover, Mn 2+ inhibits two independent sites in brain mitochondria. The primary site of Mn-induced inhibition of ATP production in brain mitochondria when succinate is substrate is either fumarase or complex II, while the likely site of the primary inhibition when glutamate plus malate are the substrates is either the glutamate/aspartate exchanger or aspartate aminotransferase.

  15. THE ISLAMIC ETHICS OF MITOCHONDRIA TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    Anke Iman Bouzenita

    2017-12-01

    Full Text Available ABSTRACT: Biotechnology has opened a new chapter with the advent of mitochondria transplantation for cell-based therapy. Mitochondrial transplantation was successfully led to birth; however, cytoplasmic transplantation has caused apprehension, since the mixing of human ooplasm from two different maternal sources may generate mitochondrial DNA (mtDNA heteroplasmy in the offspring. Islamic legal verdicts on human cloning and somatic cell transfer have been overweighing explicit as to its prohibition, due to the change of creation, mixing of lineage and other evaluations. Is mitochondria transplantation equivalent to human cloning in that genetic information is proliferated and does it, therefore, take the same legal rule? Are there possible benefits (masalih for medical treatment that may render mitochondria transplantation permissible, or are possible harms (mafasid overweighing? Or is it a completely different procedure, taking a different rule? The paper will investigate into these questions and discuss the dimensions of Islamic ethics on the issue.

  16. Redox interplay between mitochondria and peroxisomes

    Directory of Open Access Journals (Sweden)

    Celien eLismont

    2015-05-01

    Full Text Available Reduction-oxidation or ‘redox’ reactions are an integral part of a broad range of cellular processes such as gene expression, energy metabolism, protein import and folding, and autophagy. As many of these processes are intimately linked with cell fate decisions, transient or chronic changes in cellular redox equilibrium are likely to contribute to the initiation and progression of a plethora of human diseases. Since a long time, it is known that mitochondria are major players in redox regulation and signaling. More recently, it has become clear that also peroxisomes have the capacity to impact redox-linked physiological processes. To serve this function, peroxisomes cooperate with other organelles, including mitochondria. This review provides a comprehensive picture of what is currently known about the redox interplay between mitochondria and peroxisomes in mammals. We first outline the pro- and antioxidant systems of both organelles and how they may function as redox signaling nodes. Next, we critically review and discuss emerging evidence that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. Key issues include possible physiological roles, messengers, and mechanisms. We also provide examples of how data mining of publicly-available datasets from ‘omics’ technologies can be a powerful means to gain additional insights into potential redox signaling pathways between peroxisomes and mitochondria. Finally, we highlight the need for more studies that seek to clarify the mechanisms of how mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress. The outcome of such studies may open up exciting new avenues for the community of researchers working on cellular responses to organelle-derived oxidative stress, a research field in which the role of peroxisomes is currently highly underestimated and an issue of

  17. The effect of anthralin (dithranol) on mitochondria.

    Science.gov (United States)

    Morlière, P; Dubertret, L; Sa e Melo, T; Salet, C; Fosse, M; Santus, R

    1985-05-01

    The short-term effect of topical application of anthralin (dithranol) on normal human skin was investigated by electron microscopy. Mitochondria appeared markedly damaged. By contrast other cellular structures, particularly the nuclear and cytoplasmic membranes were unchanged. In vitro experiments were therefore performed on isolated rat liver mitochondria and it was shown that anthralin acts as an uncoupler of oxidative phosphorylation. These results suggest that anthralin can inhibit the adenosine triphosphate supply in epidermal cells. This loss of energy supply in keratinocytes could explain, at least in part, the therapeutic efficiency of anthralin in psoriasis.

  18. Lactate oxidation in human skeletal muscle mitochondria

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Meinild, Anne-Kristine; Nordsborg, Nikolai B

    2013-01-01

    of four separate and specific substrate titration protocols, the respirometric analysis revealed that mitochondria were capable of oxidizing lactate in the absence of exogenous LDH. The titration of lactate and NAD(+) into the respiration medium stimulated respiration (P = 0.003). The addition...... of exogenous LDH failed to increase lactate-stimulated respiration (P = 1.0). The results further demonstrate that human skeletal muscle mitochondria cannot directly oxidize lactate within the mitochondrial matrix. Alternately, these data support previous claims that lactate is converted to pyruvate within...

  19. Mitochondria in biology and medicine--2012

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Rasmussen, Lene Juel

    2014-01-01

    as biomarkers for the diseases and most important, it opens the possibility of a treatment or a cure for a disease. "Mitochondria in Biology and Medicine" was the title of the second annual conference of Society of Mitochondrial Research and Medicine-India. The conference was organized by Rana P. Singh, Keshav...

  20. Psychological Stress and Mitochondria: A Systematic Review.

    Science.gov (United States)

    Picard, Martin; McEwen, Bruce S

    Mitochondria are multifunctional life-sustaining organelles that represent a potential intersection point between psychosocial experiences and biological stress responses. This article provides a systematic review of the effects of psychological stress on mitochondrial structure and function. A systematic review of the literature investigating the effects of psychological stress on mitochondrial function was conducted. The review focused on experimentally controlled studies allowing us to draw causal inference about the effect of induced psychological stress on mitochondria. A total of 23 studies met the inclusion criteria. All studies involved male laboratory animals, and most demonstrated that acute and chronic stressors influenced specific facets of mitochondrial function, particularly within the brain. Nineteen studies showed significant adverse effects of psychological stress on mitochondria and four found increases in function or size after stress. In humans, only six observational studies were available, none with experimental designs, and most only measured biological markers that do not directly reflect mitochondrial function, such as mitochondrial DNA copy number. Overall, evidence supports the notion that acute and chronic stressors influence various aspects of mitochondrial biology, and that chronic stress exposure can lead to molecular and functional recalibrations among mitochondria. Limitations of current animal and human studies are discussed. Maladaptive mitochondrial changes that characterize this subcellular state of stress are termed mitochondrial allostatic load. Prospective studies with sensitive measures of specific mitochondrial outcomes will be needed to establish the link between psychosocial stressors, emotional states, the resulting neuroendocrine and immune processes, and mitochondrial energetics relevant to mind-body research in humans.

  1. A non-toxic fluorogenic dye for mitochondria labeling.

    Science.gov (United States)

    Han, Junyan; Han, Myung Shin; Tung, Ching-Hsuan

    2013-11-01

    Mitochondria, powerhouses of cells, are responsible for many critical cellular functions, such as cell energy metabolism, reactive oxygen species production, and apoptosis regulation. Monitoring mitochondria morphology in live cells temporally and spatially could help with the understanding of the mechanisms of mitochondrial functional regulation and the pathogenesis of mitochondria-related diseases. A novel non-cytotoxic fluorogenic compound, AcQCy7, was developed as a mitochondria-specific dye. AcQCy7 emitted no fluorescent signal outside of cells, but it became fluorescent after intracellular hydrolysis of the acetyl group. The hydrolyzed fluorescent product was well retained in mitochondria, enabling long-lasting fluorescence imaging of mitochondria without cell washing. A 2-day culture study using AcQCy7 showed no sign of cytotoxicity, whereas a commonly used mitochondria-staining probe, Mitochondria Tracker Green, caused significant cell death even at a much lower concentration. Apoptosis-causing mitochondria fission was monitored clearly in real time by AcQCy7. A simple add-and-read mitochondria specific dye AcQCy7 has been validated in various cell models. Bright mitochondria specific fluorescent signal in treated cells lasted several days without noticeable toxicity. The probe AcQCy7 has been proofed to be a non-toxic agent for long-term mitochondria imaging. © 2013.

  2. Early Decrease in Respiration and Uncoupling Event Independent of Cytochrome c Release in PC12 Cells Undergoing Apoptosis

    Science.gov (United States)

    Berghella, Libera; Ferraro, Elisabetta

    2012-01-01

    Cytochrome c is a key molecule in mitochondria-mediated apoptosis. It also plays a pivotal role in cell respiration. The switch between these two functions occurs at the moment of its release from mitochondria. This process is therefore extremely relevant for the fate of the cell. Since cytochrome c mediates respiration, we studied the changes in respiratory chain activity during the early stages of apoptosis in order to contribute to unravel the mechanisms of cytochrome c release. We found that, during staurosporine (STS)- induced apoptosis in PC12 cells, respiration is affected before the release of cytochrome c, as shown by a decrease in the endogenous uncoupled respiration and an uncoupling event, both occurring independently of cytochrome c release. The decline in the uncoupled respiration occurs also upon Bcl-2 overexpression (which inhibits cytochrome c release), while the uncoupling event is inhibited by Bcl-2. We also observed that the first stage of nuclear condensation during STS-induced apoptosis does not depend on the release of cytochrome c into the cytosol and is a reversibile event. These findings may contribute to understand the mechanisms affecting mitochondria during the early stages of apoptosis and priming them for the release of apoptogenic factors. PMID:22666257

  3. A mitochondria-targeted mass spectrometry probe to detect glyoxals: implications for diabetes☆

    Science.gov (United States)

    Pun, Pamela Boon Li; Logan, Angela; Darley-Usmar, Victor; Chacko, Balu; Johnson, Michelle S.; Huang, Guang W.; Rogatti, Sebastian; Prime, Tracy A.; Methner, Carmen; Krieg, Thomas; Fearnley, Ian M.; Larsen, Lesley; Larsen, David S.; Menger, Katja E.; Collins, Yvonne; James, Andrew M.; Kumar, G.D. Kishore; Hartley, Richard C.; Smith, Robin A.J.; Murphy, Michael P.

    2014-01-01

    The glycation of protein and nucleic acids that occurs as a consequence of hyperglycemia disrupts cell function and contributes to many pathologies, including those associated with diabetes and aging. Intracellular glycation occurs after the generation of the reactive 1,2-dicarbonyls methylglyoxal and glyoxal, and disruption of mitochondrial function is associated with hyperglycemia. However, the contribution of these reactive dicarbonyls to mitochondrial damage in pathology is unclear owing to uncertainties about their levels within mitochondria in cells and in vivo. To address this we have developed a mitochondria-targeted reagent (MitoG) designed to assess the levels of mitochondrial dicarbonyls within cells. MitoG comprises a lipophilic triphenylphosphonium cationic function, which directs the molecules to mitochondria within cells, and an o-phenylenediamine moiety that reacts with dicarbonyls to give distinctive and stable products. The extent of accumulation of these diagnostic heterocyclic products can be readily and sensitively quantified by liquid chromatography–tandem mass spectrometry, enabling changes to be determined. Using the MitoG-based analysis we assessed the formation of methylglyoxal and glyoxal in response to hyperglycemia in cells in culture and in the Akita mouse model of diabetes in vivo. These findings indicated that the levels of methylglyoxal and glyoxal within mitochondria increase during hyperglycemia both in cells and in vivo, suggesting that they can contribute to the pathological mitochondrial dysfunction that occurs in diabetes and aging. PMID:24316194

  4. A mitochondria-targeted mass spectrometry probe to detect glyoxals: implications for diabetes.

    Science.gov (United States)

    Pun, Pamela Boon Li; Logan, Angela; Darley-Usmar, Victor; Chacko, Balu; Johnson, Michelle S; Huang, Guang W; Rogatti, Sebastian; Prime, Tracy A; Methner, Carmen; Krieg, Thomas; Fearnley, Ian M; Larsen, Lesley; Larsen, David S; Menger, Katja E; Collins, Yvonne; James, Andrew M; Kumar, G D Kishore; Hartley, Richard C; Smith, Robin A J; Murphy, Michael P

    2014-02-01

    The glycation of protein and nucleic acids that occurs as a consequence of hyperglycemia disrupts cell function and contributes to many pathologies, including those associated with diabetes and aging. Intracellular glycation occurs after the generation of the reactive 1,2-dicarbonyls methylglyoxal and glyoxal, and disruption of mitochondrial function is associated with hyperglycemia. However, the contribution of these reactive dicarbonyls to mitochondrial damage in pathology is unclear owing to uncertainties about their levels within mitochondria in cells and in vivo. To address this we have developed a mitochondria-targeted reagent (MitoG) designed to assess the levels of mitochondrial dicarbonyls within cells. MitoG comprises a lipophilic triphenylphosphonium cationic function, which directs the molecules to mitochondria within cells, and an o-phenylenediamine moiety that reacts with dicarbonyls to give distinctive and stable products. The extent of accumulation of these diagnostic heterocyclic products can be readily and sensitively quantified by liquid chromatography-tandem mass spectrometry, enabling changes to be determined. Using the MitoG-based analysis we assessed the formation of methylglyoxal and glyoxal in response to hyperglycemia in cells in culture and in the Akita mouse model of diabetes in vivo. These findings indicated that the levels of methylglyoxal and glyoxal within mitochondria increase during hyperglycemia both in cells and in vivo, suggesting that they can contribute to the pathological mitochondrial dysfunction that occurs in diabetes and aging. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Effect of heavy water on isolated rat liver mitochondria

    International Nuclear Information System (INIS)

    Huebner, G.

    1981-01-01

    The rate of O 2 consumption by isolated rat liver mitochondria was determined polarographically with a Clark electrode at 25 0 C in the active (state 3), strongly coupled (state 4) and decoupled state of the mitochondria in media containing H 2 16 O, D 2 16 O or H 2 18 O. The results confirm the value of the D 2 O isotope effect in the form on an O 2 -consumption inhibition. In H 2 18 O no isotope effect has been detected in the state of controlled respiration. In contrast, a strongly marked inverse isotope effect has been found in the active state after ADP addition and in the decoupled state after DNP addition. This inverse isotope effect occurs in reactions involving a preceding equilibrium. According to the chemiosmotic hypothesis of oxidative phosphorylation the formation of hydronium ions is part of this reaction. The equilibrium constant k 2 = 0.9774 for the hydronium ion in H 2 16 O and H 2 18 O implies that the formation of the hydronium ion in H 2 18 O is preferred to that in H 2 16 O. The high inverse H 2 18 O isotope effect respiration shows that the formation of H 3 O + contributes to the vectorial proton transport, probably as a preceding equilibrium, and that in the active state of the respiratory chain this reaction may be the rate-determining step. (author)

  6. Lipid droplets interact with mitochondria using SNAP23

    DEFF Research Database (Denmark)

    Jägerström, Sara; Polesie, Sam; Wickström, Ylva

    2009-01-01

    peroxisomes and the endoplasmic reticulum. We have used electron and confocal microscopy to demonstrate that LD form complexes with mitochondria in NIH 3T3 fibroblasts. Using an in vitro system of purified LD and mitochondria, we also show the formation of the LD-mitochondria complex, in which cytosolic...... factors are involved. Moreover, the presence of LD markers in mitochondria isolated by subcellular fractionations is demonstrated. Finally, ablation of SNAP23 using siRNA reduced complex formation and beta oxidation, which suggests that the LD-mitochondria complex is functional in the cell....

  7. Erythroid cell mitochondria receive endosomal iron by a "kiss-and-run" mechanism.

    Science.gov (United States)

    Hamdi, Amel; Roshan, Tariq M; Kahawita, Tanya M; Mason, Anne B; Sheftel, Alex D; Ponka, Prem

    2016-12-01

    In erythroid cells, more than 90% of transferrin-derived iron enters mitochondria where ferrochelatase inserts Fe 2+ into protoporphyrin IX. However, the path of iron from endosomes to mitochondrial ferrochelatase remains elusive. The prevailing opinion is that, after its export from endosomes, the redox-active metal spreads into the cytosol and mysteriously finds its way into mitochondria through passive diffusion. In contrast, this study supports the hypothesis that the highly efficient transport of iron toward ferrochelatase in erythroid cells requires a direct interaction between transferrin-endosomes and mitochondria (the "kiss-and-run" hypothesis). Using a novel method (flow sub-cytometry), we analyze lysates of reticulocytes after labeling these organelles with different fluorophores. We have identified a double-labeled population definitively representing endosomes interacting with mitochondria, as demonstrated by confocal microscopy. Moreover, we conclude that this endosome-mitochondrion association is reversible, since a "chase" with unlabeled holotransferrin causes a time-dependent decrease in the size of the double-labeled population. Importantly, the dissociation of endosomes from mitochondria does not occur in the absence of holotransferrin. Additionally, mutated recombinant holotransferrin, that cannot release iron, significantly decreases the uptake of 59 Fe by reticulocytes and diminishes 59 Fe incorporation into heme. This suggests that endosomes, which are unable to provide iron to mitochondria, cause a "traffic jam" leading to decreased endocytosis of holotransferrin. Altogether, our results suggest that a molecular mechanism exists to coordinate the iron status of endosomal transferrin with its trafficking. Besides its contribution to the field of iron metabolism, this study provides evidence for a new intracellular trafficking pathway of organelles. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Visual light effects on mitochondria: The potential implications in relation to glaucoma.

    Science.gov (United States)

    Osborne, Neville N; Núñez-Álvarez, Claudia; Del Olmo-Aguado, Susana; Merrayo-Lloves, Jesús

    2017-09-01

    Light of different wave-lengths have the potential to interact with four major mitochondrial protein complexes that are involved in the generation of ATP. Neurones of the central nervous system have an absolute dependence on mitochondrial generated ATP. Laboratory studies show that short-wave or blue light (400-480nm) that impinges on the retina affect flavin and cytochrome constituents associated with mitochondria to decrease the rate of ATP formation, stimulate ROS and results in cell death. This suggests that blue light could potentially have a negative influence on retinal ganglion cell (RGC) mitochondria that are abundant and not shielded by macular pigments as occurs for photoreceptor mitochondria. This might be of significance in glaucoma where it is likely that RGC mitochondria are already affected and therefore be more susceptible to blue light. Thus simply filtering out some natural blue light from entering the eye might be beneficial for the treatment of glaucoma. Long-wave or red light (650-800nm) affects mitochondrial complex IV or cytochrome oxidase to increase the rate of formation of ATP and ROS causing the generation of a number of beneficial factors. Significantly, laboratory studies show that increasing the normal amount of natural red light reaching rat RGC mitochondria in situ, subjected to ischemia, proved to be beneficial. A challenge now is to test whether extra red light delivered to the human retina can slow-down RGC loss in glaucoma. Such a methodology has also the advantage of being non-invasive. One very exciting possibility might be in the production of a lens where solar UV light is convertes to add to the amount of natural red light entering the eye. Copyright © 2016 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  9. Cardiovascular Disease, Mitochondria, and Traditional Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Jie Wang

    2015-01-01

    Full Text Available Recent studies demonstrated that mitochondria play an important role in the cardiovascular system and mutations of mitochondrial DNA affect coronary artery disease, resulting in hypertension, atherosclerosis, and cardiomyopathy. Traditional Chinese medicine (TCM has been used for thousands of years to treat cardiovascular disease, but it is not yet clear how TCM affects mitochondrial function. By reviewing the interactions between the cardiovascular system, mitochondrial DNA, and TCM, we show that cardiovascular disease is negatively affected by mutations in mitochondrial DNA and that TCM can be used to treat cardiovascular disease by regulating the structure and function of mitochondria via increases in mitochondrial electron transport and oxidative phosphorylation, modulation of mitochondrial-mediated apoptosis, and decreases in mitochondrial ROS. However further research is still required to identify the mechanism by which TCM affects CVD and modifies mitochondrial DNA.

  10. Fluoroacetylcarnitine: metabolism and metabolic effects in mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Bremer, J; Davis, E J

    1973-01-01

    The metabolism and metabolic effects of fluoroacetylcarnitine have been investigated. Carnitineacetyltransferase transfers the fluoro-acetyl group of fluoroacetylcarnitine nearly as rapidly to CoA as the acetyl group of acetylcarnitine. Fluorocitrate is then formed by citrate synthase, but this second reaction is relatively slow. The fluorocitrate formed intramitochondrially inhibits the metabolism of citrate. In heart and skeletal muscle mitochondria the accumulated citrate inhibits citrate synthesis and the ..beta..-oxidation of fatty acids. Free acetate is formed, presumably because accumulated acetyl-CoA is hydrolyzed. In liver mitochondria the accumulation of citrate leads to a relatively increased rate of ketogenesis. Increased ketogenesis is obtained also upon the addition of citrate to the reaction mixture.

  11. Effect of simvastatin on vascular tone in porcine coronary artery: Potential role of the mitochondria

    International Nuclear Information System (INIS)

    Almukhtar, H.; Garle, M.J.; Smith, P.A.; Roberts, R.E.

    2016-01-01

    Statins induce acute vasorelaxation which may contribute to the overall benefits of statins in the treatment of cardiovascular disease. The mechanism underlying this relaxation is unknown. As statins have been shown to alter mitochondrial function, in this study we investigated the role of mitochondria in the relaxation to simvastatin. Relaxation of porcine coronary artery segments by statins was measured using isolated tissue baths. Mitochondrial activity was determined by measuring changes in rhodamine 123 fluorescence. Changes in intracellular calcium levels were determined in freshly isolated smooth muscle cells with Fluo-4 using standard epifluorescent imaging techniques. Simvastatin, but not pravastatin, produced a slow relaxation of the coronary artery, which was independent of the endothelium. The relaxation was attenuated by the mitochondrial complex I inhibitor rotenone (10 μM) and the complex III inhibitor myxothiazol (10 μM), or a combination of the two. The complex III inhibitor antimycin A (10 μM) produced a similar time-dependent relaxation of the porcine coronary artery, which was attenuated by rotenone. Changes in rhodamine 123 fluorescence showed that simvastatin (10 μM) depolarized the membrane potential of mitochondria in both isolated mitochondria and intact blood vessels. Simvastatin and antimycin A both inhibited calcium-induced contractions in isolated blood vessels and calcium influx in smooth muscle cells and this inhibition was prevented by rotenone. In conclusion, simvastatin produces an endothelium-independent relaxation of the porcine coronary artery which is dependent, in part, upon effects on the mitochondria. The effects on the mitochondria may lead to a reduction in calcium influx and hence relaxation of the blood vessel. - Highlights: • Simvastatin produces a relaxation of the porcine coronary artery. • This relaxation is inhibited by mitochondrial complex inhibitors. • Simvastatin alters mitochondrial membrane potential

  12. Effect of simvastatin on vascular tone in porcine coronary artery: Potential role of the mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Almukhtar, H.; Garle, M.J.; Smith, P.A.; Roberts, R.E., E-mail: richard.roberts@nottingham.ac.uk

    2016-08-15

    Statins induce acute vasorelaxation which may contribute to the overall benefits of statins in the treatment of cardiovascular disease. The mechanism underlying this relaxation is unknown. As statins have been shown to alter mitochondrial function, in this study we investigated the role of mitochondria in the relaxation to simvastatin. Relaxation of porcine coronary artery segments by statins was measured using isolated tissue baths. Mitochondrial activity was determined by measuring changes in rhodamine 123 fluorescence. Changes in intracellular calcium levels were determined in freshly isolated smooth muscle cells with Fluo-4 using standard epifluorescent imaging techniques. Simvastatin, but not pravastatin, produced a slow relaxation of the coronary artery, which was independent of the endothelium. The relaxation was attenuated by the mitochondrial complex I inhibitor rotenone (10 μM) and the complex III inhibitor myxothiazol (10 μM), or a combination of the two. The complex III inhibitor antimycin A (10 μM) produced a similar time-dependent relaxation of the porcine coronary artery, which was attenuated by rotenone. Changes in rhodamine 123 fluorescence showed that simvastatin (10 μM) depolarized the membrane potential of mitochondria in both isolated mitochondria and intact blood vessels. Simvastatin and antimycin A both inhibited calcium-induced contractions in isolated blood vessels and calcium influx in smooth muscle cells and this inhibition was prevented by rotenone. In conclusion, simvastatin produces an endothelium-independent relaxation of the porcine coronary artery which is dependent, in part, upon effects on the mitochondria. The effects on the mitochondria may lead to a reduction in calcium influx and hence relaxation of the blood vessel. - Highlights: • Simvastatin produces a relaxation of the porcine coronary artery. • This relaxation is inhibited by mitochondrial complex inhibitors. • Simvastatin alters mitochondrial membrane potential

  13. Response of skeletal muscle mitochondria to hypoxia.

    Science.gov (United States)

    Hoppeler, Hans; Vogt, Michael; Weibel, Ewald R; Flück, Martin

    2003-01-01

    This review explores the current concepts relating the structural and functional modifications of skeletal muscle mitochondria to the molecular mechanisms activated when organisms are exposed to a hypoxic environment. In contrast to earlier assumptions it is now established that permanent or long-term exposure to severe environmental hypoxia decreases the mitochondrial content of muscle fibres. Oxidative muscle metabolism is shifted towards a higher reliance on carbohydrates as a fuel, and intramyocellular lipid substrate stores are reduced. Moreover, in muscle cells of mountaineers returning from the Himalayas, we find accumulations of lipofuscin, believed to be a mitochondrial degradation product. Low mitochondrial contents are also observed in high-altitude natives such as Sherpas. In these subjects high-altitude performance seems to be improved by better coupling between ATP demand and supply pathways as well as better metabolite homeostasis. The hypoxia-inducible factor 1 (HIF-1) has been identified as a master regulator for the expression of genes involved in the hypoxia response, such as genes coding for glucose transporters, glycolytic enzymes and vascular endothelial growth factor (VEGF). HIF-1 achieves this by binding to hypoxia response elements in the promoter regions of these genes, whereby the increase of HIF-1 in hypoxia is the consequence of a reduced degradation of its dominant subunit HIF-1a. A further mechanism that seems implicated in the hypoxia response of muscle mitochondria is related to the formation of reactive oxygen species (ROS) in mitochondria during oxidative phosphorylation. How exactly ROS interfere with HIF-1a as well as MAP kinase and other signalling pathways is debated. The current evidence suggests that mitochondria themselves could be important players in oxygen sensing.

  14. Oxidative damage and aging: spotlight on mitochondria.

    Science.gov (United States)

    Linford, Nancy J; Schriner, Samuel E; Rabinovitch, Peter S

    2006-03-01

    Whereas free radical damage has been proposed as a key component in the tissue degeneration associated with aging, there has been little evidence that free radical damage limits life span in mammals. The current research shows that overexpression of the antioxidant enzyme catalase in mitochondria can extend mouse life span. These results highlight the importance of mitochondrial damage in aging and suggest that when targeted appropriately, boosting antioxidant defenses can increase mammalian life span.

  15. Pyruvate transport by thermogenic-tissue mitochondria.

    OpenAIRE

    Proudlove, M O; Beechey, R B; Moore, A L

    1987-01-01

    1. Mitochondria isolated from the thermogenic spadices of Arum maculatum and Sauromatum guttatum plants oxidized external NADH, succinate, citrate, malate, 2-oxoglutarate and pyruvate without the need to add exogenous cofactors. 2. Oxidation of substrates was virtually all via the alternative oxidase, the cytochrome pathway constituting only 10-20% of the total activity, depending on the stage of spadix development. 3. During later stages of spadix development, pyruvate oxidation was enhanced...

  16. Regulation of protein phosphorylation in oat mitochondria

    International Nuclear Information System (INIS)

    Pike, C.; Kopeck, K.; Sceppa, E.

    1989-01-01

    We sought to identify phosphorylated proteins in isolated oat mitocchondria and to characterize the enzymatic and regulatory properties of the protein kinase(s). Mitochondria from oats (Avena sativa L. cv. Garry) were purified on Percoll gradients. Mitochondria were incubated with 32 P-γ-ATP; proteins were separated by SDS-PAGE. A small number of bands was detected on autoradiograms, most prominently at 70 kD and 42 kD; the latter band has been tentatively identified as a subunit of the pyruvate dehydrogenase complex, a well-known phosphoprotein. The protein kinase(s) could also phosphorylate casein, but not histone. Spermine enhanced the phosphorylation of casein and inhibited the phosphorylation of the 42 kD band. These studies were carried out on both intact and burst mitochondria. Control by calcium and other ions was investigated. The question of the action of regulators on protein kinase or protein phosphatase was studied by the use of 35 S-adenosine thiotriphosphate

  17. Mitochondria in anthropology and forensic medicine.

    Science.gov (United States)

    Grzybowski, Tomasz; Rogalla, Urszula

    2012-01-01

    Mitochondria's role in crucial metabolic pathways is probably the first answer which comes to our minds for the question: what do these tiny organelles serve for? However, specific features of their DNA made them extremely useful also in the field of anthropology and forensics. MtDNA analyses became a milestone in the complex task of unraveling earliest human migrations. Evidence provided by these experiments left no doubts on modern humans origins pointing to Africa being our cradle. It also contributed to interpretation of putative ways of our dispersal around Asia and Americas thousands years ago. On the other hand, analysis of mtDNA is well established and valuable tool in forensic genetics. When other definitely more popular markers give no answer on identity, it is the time to employ information carried by mitochondria. This chapter summarizes not only current reports on the role of mitochondria in forensics and reconstruction of modern humans phylogeny, but also calls one's attention to a broad range of difficulties and constraints associated with mtDNA analyses.

  18. Role of mitochondria in parvovirus pathology.

    Directory of Open Access Journals (Sweden)

    Jonna Nykky

    Full Text Available Proper functioning of the mitochondria is crucial for the survival of the cell. Viruses are able to interfere with mitochondrial functions as they infect the host cell. Parvoviruses are known to induce apoptosis in infected cells, but the role of the mitochondria in parvovirus induced cytopathy is only partially known. Here we demonstrate with confocal and electron microscopy that canine parvovirus (CPV associated with the mitochondrial outer membrane from the onset of infection. During viral entry a transient depolarization of the mitochondrial transmembrane potential and increase in ROS level was detected. Subsequently, mitochondrial homeostasis was normalized shortly, as detected by repolarization of the mitochondrial membrane and decrease of ROS. Indeed, activation of cell survival signalling through ERK1/2 cascade was observed early in CPV infected cells. At 12 hours post infection, concurrent with the expression of viral non-structural protein 1, damage to the mitochondrial structure and depolarization of its membrane were apparent. Results of this study provide additional insight of parvovirus pathology and also more general information of virus-mitochondria association.

  19. Mitochondria and the evolutionary roots of cancer

    International Nuclear Information System (INIS)

    Davila, Alfonso F; Zamorano, Pedro

    2013-01-01

    Cancer disease is inherent to, and widespread among, metazoans. Yet, some of the hallmarks of cancer such as uncontrolled cell proliferation, lack of apoptosis, hypoxia, fermentative metabolism and free cell motility (metastasis) are akin to a prokaryotic lifestyle, suggesting a link between cancer disease and evolution. In this hypothesis paper, we propose that cancer cells represent a phenotypic reversion to the earliest stage of eukaryotic evolution. This reversion is triggered by the dysregulation of the mitochondria due to cumulative oxidative damage to mitochondrial and nuclear DNA. As a result, the phenotype of normal, differentiated cells gradually reverts to the phenotype of a facultative anaerobic, heterotrophic cell optimized for survival and proliferation in hypoxic environments. This phenotype matches the phenotype of the last eukaryotic common ancestor (LECA) that resulted from the endosymbiosis between an α-proteobacteria (which later became the mitochondria) and an archaebacteria. As such, the evolution of cancer within one individual can be viewed as a recapitulation of the evolution of the eukaryotic cell from fully differentiated cells to LECA. This evolutionary model of cancer is compatible with the current understanding of the disease, and explains the evolutionary basis for most of the hallmarks of cancer, as well as the link between the disease and aging. It could also open new avenues for treatment directed at reestablishing the synergy between the mitochondria and the cancerous cell. (paper)

  20. Plasmodium falciparum mitochondria import tRNAs along with an active phenylalanyl-tRNA synthetase.

    Science.gov (United States)

    Sharma, Arvind; Sharma, Amit

    2015-02-01

    The Plasmodium falciparum protein translation enzymes aminoacyl-tRNA synthetases (aaRSs) are an emergent family of drug targets. The aaRS ensemble catalyses transfer of amino acids to cognate tRNAs, thus providing charged tRNAs for ribosomal consumption. P. falciparum proteome expression relies on a total of 36 aaRSs for the three translationally independent compartments of cytoplasm, apicoplast and mitochondria. In the present study, we show that, of this set of 36, a single genomic copy of mitochondrial phenylalanyl-tRNA synthetase (mFRS) is targeted to the parasite mitochondria, and that the mFRS gene is exclusive to malaria parasites within the apicomplexan phyla. Our protein cellular localization studies based on immunofluorescence data show that, along with mFRS, P. falciparum harbours two more phenylalanyl-tRNA synthetase (FRS) assemblies that are localized to its apicoplast and cytoplasm. The 'extra' mFRS is found in mitochondria of all asexual blood stage parasites and is competent in aminoacylation. We show further that the parasite mitochondria import tRNAs from the cytoplasmic tRNA pool. Hence drug targeting of FRSs presents a unique opportunity to potentially stall protein production in all three parasite translational compartments.

  1. The Parkinson disease-related protein DJ-1 counteracts mitochondrial impairment induced by the tumour suppressor protein p53 by enhancing endoplasmic reticulum-mitochondria tethering.

    Science.gov (United States)

    Ottolini, Denis; Calì, Tito; Negro, Alessandro; Brini, Marisa

    2013-06-01

    DJ-1 was first identified as an oncogene. More recently, mutations in its gene have been found causative for autosomal recessive familial Parkinson disease. Numerous studies support the DJ-1 role in the protection against oxidative stress and maintenance of mitochondria structure; however, the mechanism of its protective function remains largely unknown. We investigated whether mitochondrial Ca(2+) homeostasis, a key parameter in cell physiology, could be a target for DJ-1 action. Here, we show that DJ-1 modulates mitochondrial Ca(2+) transients induced upon cell stimulation with an 1,4,5-inositol-tris-phosphate agonist by favouring the endoplasmic reticulum (ER)-mitochondria tethering. A reduction of DJ-1 levels results in mitochondria fragmentation and decreased mitochondrial Ca(2+) uptake in stimulated cells. To functionally couple these effects with the well-recognized cytoprotective role of DJ-1, we investigated its action in respect to the tumour suppressor p53. p53 overexpression in HeLa cells impairs their ability to accumulate Ca(2+) in the mitochondrial matrix, causes alteration of the mitochondrial morphology and reduces ER-mitochondria contact sites. Mitochondrial impairments are independent from Drp1 activation, since the co-expression of the dominant negative mutant of Drp1 failed to abolish them. DJ-1 overexpression prevents these alterations by re-establishing the ER-mitochondria tethering. Similarly, the co-expression of the pro-fusion protein Mitofusin 2 blocks the effects induced by p53 on mitochondria, confirming that the modulation of the ER-mitochondria contact sites is critical to mitochondria integrity. Thus, the impairment of ER-mitochondria communication, as a consequence of DJ-1 loss-of-function, may be detrimental for mitochondria-related processes and be at the basis of mitochondrial dysfunction observed in Parkinson disease.

  2. Are Independent Probes Truly Independent?

    Science.gov (United States)

    Camp, Gino; Pecher, Diane; Schmidt, Henk G.; Zeelenberg, Rene

    2009-01-01

    The independent cue technique has been developed to test traditional interference theories against inhibition theories of forgetting. In the present study, the authors tested the critical criterion for the independence of independent cues: Studied cues not presented during test (and unrelated to test cues) should not contribute to the retrieval…

  3. BioMEMS for mitochondria medicine

    Science.gov (United States)

    Padmaraj, Divya

    A BioMEMS device to study cell-mitochondrial physiological functionalities was developed. The pathogenesis of many diseases including obesity, diabetes and heart failure as well as aging has been linked to functional defects of mitochondria. The synthesis of Adenosine Tri Phosphate (ATP) is determined by the electrical potential across the inner mitochondrial membrane and by the pH difference due to proton flux across it. Therefore, electrical characterization by E-fields with complementary chemical testing was used here. The BioMEMS device was fabricated as an SU-8 based microfluidic system with gold electrodes on SiO2/Si wafers for electromagnetic interrogation. Ion Sensitive Field Effect Transistors (ISFETs) were incorporated for proton studies important in the electron transport chain, together with monitoring Na+, K+ and Ca++ ions for ion channel studies. ISFETs are chemically sensitive Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices and their threshold voltage is directly proportional to the electrolytic H+ ion variation. These ISFETs (sensitivity ˜55 mV/pH for H+) were further realized as specific ion sensitive Chemical Field Effect Transistors (CHEMFETs) by depositing a specific ion sensitive membrane on the gate. Electrodes for dielectric spectroscopy studies of mitochondria were designed as 2- and 4-probe structures for optimized operation over a wide frequency range. In addition, to limit polarization effects, a 4-electrode set-up with unique meshed pickup electrodes (7.5x7.5 mum2 loops with 4 mum wires) was fabricated. Sensitivity of impedance spectroscopy to membrane potential changes was confirmed by studying the influence of uncouplers and glucose on mitochondria. An electrical model was developed for the mitochondrial sample, and its frequency response correlated with impedance spectroscopy experiments of sarcolemmal mitochondria. Using the mesh electrode structure, we obtained a reduction of 83.28% in impedance at 200 Hz. COMSOL

  4. Localization of mitochondria in living cells with rhodamine 123.

    Science.gov (United States)

    Johnson, L V; Walsh, M L; Chen, L B

    1980-01-01

    The laser dye rhodamine 123 is shown to be a specific probe for the localization of mitochondria in living cells. By virtue of its selectivity for mitochondria and its fluorescent properties, the detectability of mitochondria stained with rhodamine 123 is significantly improved over that provided by conventional light microscopic techniques. With the use of rhodamine 123, it is possible to detect alterations in mitochondrial distribution following transformation by Rous sarcoma virus and changes in the shape and organization of mitochondria induced by colchicine treatment. Images PMID:6965798

  5. Intra- and Intercellular Quality Control Mechanisms of Mitochondria

    Directory of Open Access Journals (Sweden)

    Yoshimitsu Kiriyama

    2017-12-01

    Full Text Available Mitochondria function to generate ATP and also play important roles in cellular homeostasis, signaling, apoptosis, autophagy, and metabolism. The loss of mitochondrial function results in cell death and various types of diseases. Therefore, quality control of mitochondria via intra- and intercellular pathways is crucial. Intracellular quality control consists of biogenesis, fusion and fission, and degradation of mitochondria in the cell, whereas intercellular quality control involves tunneling nanotubes and extracellular vesicles. In this review, we outline the current knowledge on the intra- and intercellular quality control mechanisms of mitochondria.

  6. Enzymic synthesis of γ-coniceine in Conium maculatum chloroplasts and mitochondria.

    Science.gov (United States)

    Roberts, M F

    1981-08-01

    Further studies of the transaminase responsible for the first committed step in alkaloid formation in Conium maculatum have shown the L-alanine: 5-ketooctanal transaminase to occur in both the mitochondria and chloroplast. Experiments suggest that these enzymes are the isoenzymes Transaminase A and B respectively previously isolated by the author. It is suggested that the chloroplast enzyme is normally responsible for alkaloid production.

  7. Changes in calcium uptake rate by rat cardiac mitochondria during postnatal development.

    Science.gov (United States)

    Bassani, R A; Fagian, M M; Bassani, J W; Vercesi, A E

    1998-10-01

    Ca2+ uptake, transmembrane electrical potential (Deltapsim) and oxygen consumption were measured in isolated ventricular mitochondria of rats from 3 days to 5 months of age. Estimated values of ruthenium red-sensitive, succinate-supported maximal rate of Ca2+ uptake (Vmax, expressed as nmol Ca2+/min/mg protein) were higher in neonates and gradually fell during postnatal development (from 435+/-24 at 3-6 days, to 156+/-10 in adults,Palpha-ketoglutarate as substrates) and state 3ADP (alpha-ketoglutarate-supported) respiration rates, as well as Deltapsim values (approximately-150 mV). Respiration-independent Deltapsim and Ca2+ uptake, supported by valinomycin-induced K+ efflux were also investigated at these ages. A transient Deltapsim (approximately -30 mV) was evoked by valinomycin in both neonatal and adult mitochondria. Respiration-independent Ca2+ uptake was also transient, but its initial rate was significantly higher in neonates than in adults (49. 4+/-10.0v 28.0+/-5.7 mmol Ca2+/min/mg protein,P<0.01). These results indicate that Ca2+ uptake capacity of rat cardiac mitochondria is remarkably high just after birth and declines over the first weeks of postnatal life, without change in apparent affinity of the transporter. Increased mitochondrial Ca2+ uptake rate in neonates appears to be related to the uniporter itself, rather than to modification of the driving force of the transport. Copyright 1998 Academic Press

  8. The Rise of Mitochondria in Medicine

    Science.gov (United States)

    Picard, Martin; Wallace, Douglas C; Burelle, Yan

    2016-01-01

    Once considered exclusively the cell's powerhouse, mitochondria are now recognized to perform multiple essential cellular functions beyond energy production, impacting most areas of cell biology and medicine. Since the emergence of molecular biology and the discovery of pathogenic mitochondrial DNA defects in the 1980's, research advances have revealed a number of common human diseases which share an underlying pathogenesis involving mitochondrial dysfunction. Mitochondria undergo function-defining dynamic shape changes, communicate with each other, regulate gene expression within the nucleus, modulate synaptic transmission within the brain, release molecules that contribute to oncogenic transformation and trigger inflammatory responses systemically, and influence the regulation of complex physiological systems. Novel “mitopathogenic” mechanisms are thus being uncovered across a number of medical disciplines including genetics, oncology, neurology, immunology, and critical care medicine. Increasing knowledge of the bioenergetic aspects of human disease has provided new opportunities for diagnosis, therapy, prevention, and in connecting various domains of medicine. In this article, we overview specific aspects of mitochondrial biology that have contributed to – and likely will continue to enhance the progress of modern medicine. PMID:27423788

  9. Mitochondria: Target organelles for estrogen action

    Directory of Open Access Journals (Sweden)

    Małgorzata Chmielewska

    2017-06-01

    Full Text Available Estrogens belong to a group of sex hormones, which have been shown to act in multidirectional way. Estrogenic effects are mediated by two types of intracellular receptors: estrogen receptor 1 (ESR1 and estrogen receptor 2 (ESR2. There are two basic mechanisms of estrogen action: 1 classical-genomic, in which the ligand-receptor complex acts as a transcriptional factor and 2 a nongenomic one, which is still not fully understood, but has been seen to lead to distinct biological effects, depending on tissue and ligand type. It is postulated that nongenomic effects may be associated with membrane signaling and the presence of classical nuclear receptors within the cell membrane. Estrogens act in a multidirectional way also within cell organelles. It is assumed that there is a mechanism which manages the migration of ESR into the mitochondrial membrane, wherein the exogenous estrogen affect the morphology of mitochondria. Estrogen, through its receptor, can directly modulate mitochondrial gene expression. Moreover, by regulating the level of reactive oxygen species, estrogens affect the biology of mitochondria. The considerations presented in this paper indicate the pleiotropic effects of estrogens, which represent a multidirectional pathway of signal transduction.

  10. Gastrointestinal dysfunction in autism spectrum disorder: the role of the mitochondria and the enteric microbiome

    Directory of Open Access Journals (Sweden)

    Richard E. Frye

    2015-05-01

    Full Text Available Autism spectrum disorder (ASD affects a significant number of individuals worldwide with the prevalence continuing to grow. It is becoming clear that a large subgroup of individuals with ASD demonstrate abnormalities in mitochondrial function as well as gastrointestinal (GI symptoms. Interestingly, GI disturbances are common in individuals with mitochondrial disorders and have been reported to be highly prevalent in individuals with co-occurring ASD and mitochondrial disease. The majority of individuals with ASD and mitochondrial disorders do not manifest a primary genetic mutation, raising the possibility that their mitochondrial disorder is acquired or, at least, results from a combination of genetic susceptibility interacting with a wide range of environmental triggers. Mitochondria are very sensitive to both endogenous and exogenous environmental stressors such as toxicants, iatrogenic medications, immune activation, and metabolic disturbances. Many of these same environmental stressors have been associated with ASD, suggesting that the mitochondria could be the biological link between environmental stressors and neurometabolic abnormalities associated with ASD. This paper reviews the possible links between GI abnormalities, mitochondria, and ASD. First, we review the link between GI symptoms and abnormalities in mitochondrial function. Second, we review the evidence supporting the notion that environmental stressors linked to ASD can also adversely affect both mitochondria and GI function. Third, we review the evidence that enteric bacteria that are overrepresented in children with ASD, particularly Clostridia spp., produce short-chain fatty acid metabolites that are potentially toxic to the mitochondria. We provide an example of this gut–brain connection by highlighting the propionic acid rodent model of ASD and the clinical evidence that supports this animal model. Lastly, we discuss the potential therapeutic approaches that could be

  11. The import of the transcription factor STAT3 into mitochondria depends on GRIM-19, a component of the electron transport chain.

    Science.gov (United States)

    Tammineni, Prasad; Anugula, Chandrashekhar; Mohammed, Fareed; Anjaneyulu, Murari; Larner, Andrew C; Sepuri, Naresh Babu Venkata

    2013-02-15

    The signal transducer and activator of transcription 3 (STAT3), a nuclear transcription factor, is also present in mitochondria and regulates cellular respiration in a transcriptional-independent manner. The mechanism of STAT3 import into mitochondria remains obscure. In this report we show that mitochondrial-localized STAT3 resides in the inner mitochondrial membrane. In vitro import studies show that the gene associated with retinoid interferon induced cell mortality 19 (GRIM-19), a complex I subunit that acts as a chaperone to recruit STAT3 into mitochondria. In addition, GRIM-19 enhances the integration of STAT3 into complex I. A S727A mutation in STAT3 reduces its import and assembly even in the presence of GRIM-19. Together, our studies unveil a novel chaperone function for GRIM-19 in the recruitment of STAT3 into mitochondria.

  12. 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

  13. Electronic microscopy evidence for mitochondria as targets for Cd/Se/Te-based quantum dot 705 toxicity in vivo

    Directory of Open Access Journals (Sweden)

    Chia-Hua Lin

    2012-07-01

    Full Text Available The safety of quantum dots (QDs 705 was evaluated in this study. Mice were treated with QD705 (intravenous at a single dose of (40 pmol for 4, 12, 16, and 24 weeks. Effects of QD705 on kidneys were examined. While there was a lack of histopathology, reduction in renal functions was detected at 16 weeks. Electron microscopic examination revealed alterations in proximal convoluted tubule (PCT cell mitochondria at even much earlier time, including disorientation and reduction of mitochondrial number (early change, mitochondrial swelling, and later compensatory mitochondrial hypertrophy (enlargement mitochondria: giant mitochondria with hyperplastic inner cristae as well as mitochondrial hyperplasia (increase in mitochondrial biogenesis and numbers were observed. Such changes probably represent compensatory attempts of the mitochondria for functional loss or reduction of mitochondria in QD705 treated animals. Moreover, degeneration of mitochondria (myelin-figure and cytoplasmic membranous body formation and degradation of cytoplasmic materials (isolated cytoplasmic pockets of degenerated materials and focal cytoplasmic degradation also occurred in later time points (16–24 weeks. Such mitochondrial changes were not identical with those induced by pure cadmium. Taken together, we suggest that mitochondria appeared to be the target of QD705 toxicity and specific mitochondrial markers may be useful parameters for toxicity assessments of QDs or other metal-based nanomaterials.

  14. Endurance training increases the efficiency of rat skeletal muscle mitochondria.

    Science.gov (United States)

    Zoladz, Jerzy A; Koziel, Agnieszka; Woyda-Ploszczyca, Andrzej; Celichowski, Jan; Jarmuszkiewicz, Wieslawa

    2016-10-01

    Endurance training enhances mitochondrial oxidative capacity, but its effect on mitochondria functioning is poorly understood. In the present study, the influence of an 8-week endurance training on the bioenergetic functioning of rat skeletal muscle mitochondria under different assay temperatures (25, 35, and 42 °C) was investigated. The study was performed on 24 adult 4-month-old male Wistar rats, which were randomly assigned to either a treadmill training group (n = 12) or a sedentary control group (n = 12). In skeletal muscles, endurance training stimulated mitochondrial biogenesis and oxidative capacity. In isolated mitochondria, endurance training increased the phosphorylation rate and elevated levels of coenzyme Q. Moreover, a decrease in mitochondrial uncoupling, including uncoupling protein-mediated proton leak, was observed after training, which could explain the increased reactive oxygen species production (in nonphosphorylating mitochondria) and enhanced oxidative phosphorylation efficiency. At all studied temperatures, endurance training significantly augmented H2O2 production (and coenzyme Q reduction level) in nonphosphorylating mitochondria and decreased H2O2 production (and coenzyme Q reduction level) in phosphorylating mitochondria. Endurance training magnified the hyperthermia-induced increase in oxidative capacity and attenuated the hyperthermia-induced decline in oxidative phosphorylation efficiency and reactive oxygen species formation of nonphosphorylating mitochondria via proton leak enhancement. Thus, endurance training induces both quantitative and qualitative changes in muscle mitochondria that are important for cell signaling as well as for maintaining muscle energy homeostasis, especially at high temperatures.

  15. Transport of N-acetylglutamate in rat-liver mitochondria

    NARCIS (Netherlands)

    Meijer, A. J.; van Woerkom, G. M.; Wanders, R. J.; Lof, C.

    1982-01-01

    The permeability properties of the rat-liver mitochondrial membrane for N-acetylglutamate, the activator of carbamoyl-phosphate synthetase (ammonia), were studied. 1. Transport of N-acetylglutamate into the mitochondria was only observed in partially or fully de-energized mitochondria and when the

  16. Functional characterization of mitochondria in neutrophils: a role restricted to apoptosis

    NARCIS (Netherlands)

    Maianski, N. A.; Geissler, J.; Srinivasula, S. M.; Alnemri, E. S.; Roos, D.; Kuijpers, T. W.

    2004-01-01

    Mitochondria are known to combine life-supporting functions with participation in apoptosis by controlling caspase activity. Here, we report that in human blood neutrophils the mitochondria are different, because they preserve mainly death-mediating abilities. Neutrophil mitochondria hardly

  17. Arsenate uncoupling of oxidative phosphorylation in isolated plant mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Wickes, W A; Wiskich, J T

    1976-01-01

    The uncoupling by arsenate of beetroot and cauliflower bud mitochondria showed the following characteristics: arsenate stimulation of respiration above the rate found with phosphate; inhibition of arsenate-stimulated respiration by phosphate; enhancement of arsenate-stimulated respiration by ADP; only partial prevention of this ADP-enhanced respiration by atractyloside; inhibition by oligomycin of the arsenate-stimulated respiration back to the phosphate rate; and the absence of any stimulatory effect of ADP in the presence of oligomycin. These results are qualitatively analogous to those reported for arsenate uncoupling in rat liver mitochondria. Arsenate stimulated malate oxidation, presumably by stimulating malate entry, in both beetroot and cauliflower bud mitochondria; however, high rates of oxidation, and presumably entry, were only sustained with arsenate in beetroot mitochondria. NADH was oxidized rapidly in cauliflower bud mitochondria in the presence of arsenate, showing that arsenate did not inhibit electron transfer processes.

  18. Pathophysiology of mitochondrial lipid oxidation: Role of 4-hydroxynonenal (4-HNE) and other bioactive lipids in mitochondria.

    Science.gov (United States)

    Xiao, Mengqing; Zhong, Huiqin; Xia, Lin; Tao, Yongzhen; Yin, Huiyong

    2017-10-01

    Mitochondrial lipids are essential for maintaining the integrity of mitochondrial membranes and the proper functions of mitochondria. As the "powerhouse" of a cell, mitochondria are also the major cellular source of reactive oxygen species (ROS). Oxidative stress occurs when the antioxidant system is overwhelmed by overproduction of ROS. Polyunsaturated fatty acids in mitochondrial membranes are primary targets for ROS attack, which may lead to lipid peroxidation (LPO) and generation of reactive lipids, such as 4-hydroxynonenal. When mitochondrial lipids are oxidized, the integrity and function of mitochondria may be compromised and this may eventually lead to mitochondrial dysfunction, which has been associated with many human diseases including cancer, cardiovascular diseases, diabetes, and neurodegenerative diseases. How mitochondrial lipids are oxidized and the underlying molecular mechanisms and pathophysiological consequences associated with mitochondrial LPO remain poorly defined. Oxidation of the mitochondria-specific phospholipid cardiolipin and generation of bioactive lipids through mitochondrial LPO has been increasingly recognized as an important event orchestrating apoptosis, metabolic reprogramming of energy production, mitophagy, and immune responses. In this review, we focus on the current understanding of how mitochondrial LPO and generation of bioactive lipid mediators in mitochondria are involved in the modulation of mitochondrial functions in the context of relevant human diseases associated with oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Uncoupling effect of palmitate is exacerbated in skeletal muscle mitochondria of sea-acclimatized king penguins (Aptenodytes patagonicus).

    Science.gov (United States)

    Rey, Benjamin; Duchamp, Claude; Roussel, Damien

    2017-09-01

    In king penguin juveniles, the environmental transition from a terrestrial to a marine habitat, occurring at fledging, drastically stimulates lipid catabolism and the remodelling of muscle mitochondria to sustain extensive swimming activity and thermoregulation in the cold circumpolar oceans. However, the exact nature of these mechanisms remains only partially resolved. Here we investigated, in vitro, the uncoupling effect of increasing doses of fatty acids in pectoralis muscle intermyofibrillar mitochondria isolated, either from terrestrial never-immersed or experimentally cold water immersed pre-fledging king penguins or from sea-acclimatized fledged penguins. Mitochondria exhibited much greater palmitate-induced uncoupling respiration and higher maximal oxidative capacity after acclimatization to marine life. Such effects were not reproduced experimentally after repeated immersions in cold water, suggesting that the plasticity of mitochondrial characteristics may not be primarily driven by cold exposure per se but by other aspects of sea acclimatization. Copyright © 2017. Published by Elsevier Inc.

  20. Phospholipid fatty acids in mitochondria and microsomes of wheat and rice seedling roots during aeration and anaerobiosis

    International Nuclear Information System (INIS)

    Chirkova, T.V.; Sinyutina, N.F.; Blyudzin, Yu.A.; Barskii, I.E.; Smetannikova, S.V.

    1989-01-01

    Mitochondrial and microsomal fractions were isolated from the roots after residence of wheat and rice seedlings under conditions of aeration or anaerobiosis and used to determine the percentage ratio of phospholipid fatty acids (PFA), their content, and the rate of incorporation of [2- 14 C]-acetate into them. In rice mitochondria under anaerobic influence, the ratio of unsaturated to saturated PFA was higher than the level that occurred in the control plants and PFA content remained close to the control level throughout the entire course of exposure. On the other hand, these indices declined in wheat mitochondria and microsomes of both plants. Anoxia also powerfully inhibited incorporation of labelled acetate into PFA of both membrane fractions in wheat and rice seedlings alike. Probably indicating adaptive reorganizations in composition of the main groups of PFA and inhibition of their decomposition in rice mitochondria, the obtained data are discussed in relation to greater resistance to temporary anaerobiosis in rice as compared with wheat

  1. Mitochondria in cancer: not just innocent bystanders.

    Science.gov (United States)

    Frezza, Christian; Gottlieb, Eyal

    2009-02-01

    The first half of the 20th century produced substantial breakthroughs in bioenergetics and mitochondria research. During that time, Otto Warburg observed abnormally high glycolysis and lactate production in oxygenated cancer cells, leading him to suggest that defects in mitochondrial functions are at the heart of malignant cell transformation. Warburg's hypothesis profoundly influenced the present perception of cancer metabolism, positioning what is termed aerobic glycolysis in the mainstream of clinical oncology. While some of his ideas stood the test of time, they also frequently generated misconceptions regarding the biochemical mechanisms of cell transformation. This review examines experimental evidence which supports or refutes the Warburg effect and discusses the possible advantages conferred on cancer cells by 'metabolic transformation'.

  2. Mitochondria, cognitive impairment, and Alzheimer's disease.

    Science.gov (United States)

    Mancuso, M; Calsolaro, V; Orsucci, D; Carlesi, C; Choub, A; Piazza, S; Siciliano, G

    2009-07-06

    To date, the beta amyloid (Abeta) cascade hypothesis remains the main pathogenetic model of Alzheimer's disease (AD), but its role in the majority of sporadic AD cases is unclear. The "mitochondrial cascade hypothesis" could explain many of the biochemical, genetic, and pathological features of sporadic AD. Somatic mutations in mitochondrial DNA (mtDNA) could cause energy failure, increased oxidative stress, and accumulation of Abeta, which in a vicious cycle reinforce the mtDNA damage and the oxidative stress. Despite the evidence of mitochondrial dysfunction in AD, no causative mutations in the mtDNA have been detected so far. Indeed, results of studies on the role of mtDNA haplogroups in AD are controversial. In this review we discuss the role of the mitochondria, and especially of the mtDNA, in the cascade of events leading to neurodegeneration, dementia, and AD.

  3. Melatonin, mitochondria, and the metabolic syndrome.

    Science.gov (United States)

    Cardinali, Daniel P; Vigo, Daniel E

    2017-11-01

    A number of risk factors for cardiovascular disease including hyperinsulinemia, glucose intolerance, dyslipidemia, obesity, and elevated blood pressure are collectively known as metabolic syndrome (MS). Since mitochondrial activity is modulated by the availability of energy in cells, the disruption of key regulators of metabolism in MS not only affects the activity of mitochondria but also their dynamics and turnover. Therefore, a link of MS with mitochondrial dysfunction has been suspected since long. As a chronobiotic/cytoprotective agent, melatonin has a special place in prevention and treatment of MS. Melatonin levels are reduced in diseases associated with insulin resistance like MS. Melatonin improves sleep efficiency and has antioxidant and anti-inflammatory properties, partly for its role as a metabolic regulator and mitochondrial protector. We discuss in the present review the several cytoprotective melatonin actions that attenuate inflammatory responses in MS. The clinical data that support the potential therapeutical value of melatonin in human MS are reviewed.

  4. Mitochondria and Energetic Depression in Cell Pathophysiology

    Directory of Open Access Journals (Sweden)

    Stephan Zierz

    2009-05-01

    Full Text Available Mitochondrial dysfunction is a hallmark of almost all diseases. Acquired or inherited mutations of the mitochondrial genome DNA may give rise to mitochondrial diseases. Another class of disorders, in which mitochondrial impairments are initiated by extramitochondrial factors, includes neurodegenerative diseases and syndromes resulting from typical pathological processes, such as hypoxia/ischemia, inflammation, intoxications, and carcinogenesis. Both classes of diseases lead to cellular energetic depression (CED, which is characterized by decreased cytosolic phosphorylation potential that suppresses the cell’s ability to do work and control the intracellular Ca2+ homeostasis and its redox state. If progressing, CED leads to cell death, whose type is linked to the functional status of the mitochondria. In the case of limited deterioration, when some amounts of ATP can still be generated due to oxidative phosphorylation (OXPHOS, mitochondria launch the apoptotic cell death program by release of cytochrome c. Following pronounced CED, cytoplasmic ATP levels fall below the thresholds required for processing the ATP-dependent apoptotic cascade and the cell dies from necrosis. Both types of death can be grouped together as a mitochondrial cell death (MCD. However, there exist multiple adaptive reactions aimed at protecting cells against CED. In this context, a metabolic shift characterized by suppression of OXPHOS combined with activation of aerobic glycolysis as the main pathway for ATP synthesis (Warburg effect is of central importance. Whereas this type of adaptation is sufficiently effective to avoid CED and to control the cellular redox state, thereby ensuring the cell survival, it also favors the avoidance of apoptotic cell death. This scenario may underlie uncontrolled cellular proliferation and growth, eventually resulting in carcinogenesis.

  5. The Myriad Roles of Miro in the Nervous System: Axonal Transport of Mitochondria and Beyond

    Directory of Open Access Journals (Sweden)

    Bingwei eLu

    2014-10-01

    Full Text Available Mitochondrial rho GTPase (Miro is a mitochondrial outer membrane protein containing two GTPase domains and two helix-loop-helix Ca2+-binding domains called EF hands. Pioneering genetic studies in Drosophila first revealed a key function of Miro in regulating the axonal transport of mitochondria, during which Miro forms a multi-protein transport complex with Milton and Kinesin heavy chain (KHC to link trafficking mitochondria with the microtubule cytoskeleton. Recent studies showed that through binding to the EF hands of Miro and causing conformational changes of Miro and alteration of protein-protein interactions within the transport complex, Ca2+ can alter the engagement of mitochondria with the microtubule (MT/kinesin network, offering one mechanism to match mitochondrial distribution with neuronal activity. Despite the importance of the Miro/Milton/Kinesin complex in regulating mitochondrial transport in metazoans, not all components of the transport complex are conserved in lower organisms, and transport-independent functions of Miro are emerging. Here we review the diverse functions of the evolutionarily conserved Miro proteins that are relevant to the development, maintenance, and functioning of the nervous system and discuss the potential contribution of Miro dysfunction to the pathogenesis of diseases of the nervous system.

  6. Are maternal mitochondria the selfish entities that are masters of the cells of eukaryotic multicellular organisms?

    Science.gov (United States)

    Barlow, Peter W; Baldelli, E; Baluška, Frantisek

    2009-01-01

    The Energide concept, as well as the endosymbiotic theory of eukaryotic cell organization and evolution, proposes that present-day cells of eukaryotic organisms are mosaics of specialized and cooperating units, or organelles. Some of these units were originally free-living prokaryotes, which were engulfed during evolutionary time. Mitochondria represent one of these types of previously independent organisms, the Energide, is another type. This new perspective on the organization of the cell has been further expanded to reveal the concept of a public milieu, the cytosol, in which Energides and mitochondria live, each with their own private internal milieu. The present paper discusses how the endosymbiotic theory implicates a new hypothesis about the hierarchical and communicational organization of the integrated prokaryotic components of the eukaryotic cell and provides a new angle from which to consider the theory of evolution and its bearing upon cellular complexity. Thus, it is proposed that the “selfish gene” hypothesis of Dawkins1 is not the only possible perspective for comprehending genomic and cellular evolution. Our proposal is that maternal mitochondria are the selfish “master” entities of the eukaryotic cell with respect not only to their propagation from cell-to-cell and from generation-to-generation but also to their regulation of all other cellular functions. However, it should be recognized that the concept of “master” and “servant” cell components is a metaphor; in present-day living organisms their organellar components are considered to be interdependent and inseparable. PMID:19513277

  7. Tumor-Selective Cytotoxicity of Nitidine Results from Its Rapid Accumulation into Mitochondria

    Directory of Open Access Journals (Sweden)

    Hironori Iwasaki

    2017-01-01

    Full Text Available We identified a nitidine- (NTD- accumulating organelle and evaluated the net cytotoxicity of accumulated NTD. To evaluate tumor cell selectivity of the drug, we evaluated its selective cytotoxicity against 39 human cancer cell lines (JFCR39 panel, and the profile was compared with those of known anticancer drugs. Organelle specificity of NTD was visualized using organelle-targeted fluorescent proteins. Real-time analysis of cell growth, proliferation, and cytotoxicity was performed using the xCELLigence system. Selectivity of NTD in the JFCR39 panel was evaluated. Mitochondria-specific accumulation of NTD was observed. Real-time cytotoxicity analysis suggested that the mechanism of NTD-induced cell death is independent of the cell cycle. Short-term treatment indicated that this cytotoxicity only resulted from the accumulation of NTD into the mitochondria. The results from the JFCR39 panel indicated that NTD-mediated cytotoxicity resulted from unique mechanisms compared with those of other known anticancer drugs. These results suggested that the cytotoxicity of NTD is only induced by its accumulation in mitochondria. The drug triggered mitochondrial dysfunction in less than 2 h. Similarity analysis of the selectivity of NTD in 39 tumor cell lines strongly supported the unique tumor cell specificity of NTD. Thus, these features indicate that NTD may be a promising antitumor drug for new combination chemotherapies.

  8. A survey of the interaction of calcium ions with mitochondria from different tissues and species

    Science.gov (United States)

    Carafoli, Ernesto; Lehninger, Albert L.

    1971-01-01

    A survey was made of the capacity of mitochondria isolated from a number of different tissues and species to accumulate Ca2+ from the suspending medium during electron transport. The species examined included the rat, mouse, rabbit, hamster, guinea pig, cow, chicken, turtle, blowfly, yeast and Neurospora crassa. The tissues examined included vertebrate liver, kidney, brain, heart, spleen, thyroid and adrenal cortex, and the flight muscle of the blowfly. The mitochondria from all vertebrate tissues examined showed: (a) stimulation of State 4 respiration by added Ca2+ (Ca2+/~ activation ratio about 2.0), accompanied by accumulation of Ca2+ and ejection of H+, with a H+/Ca2+ ratio about 1.0; (b) a requirement of phosphate for accumulation of large amounts of Ca2+; (c) respiration-independent high-affinity binding sites for Ca2+; (d) endogenous Ca2+, which is largely released by uncoupling agents. However, mitochondria from yeast and blowfly flight muscle are unable to accumulate Ca2+ in a respiration-dependent process and possess no high-affinity Ca2+-binding sites. These findings support the view that the high-affinity sites represent the ligand-binding sites of a specific Ca2+ `permease' or transport system in the membrane. The relatively high affinity for Ca2+, which equals or exceeds the affinity for ADP, and the generally uniform characteristics of Ca2+ transport in all the vertebrate mitochondria tested strongly suggest that respiration-linked Ca2+ accumulation plays a general and fundamental role in vertebrate cell physiology. PMID:5129264

  9. Protein oxidation in plant mitochondria as a stress indicator

    DEFF Research Database (Denmark)

    Møller, I.M.; Kristensen, B.K.

    2004-01-01

    oxidation of cysteine and methionine side chains is an important mechanism for regulating enzyme activity. Mitochondria from both mammalian and plant tissues contain a number of oxidised proteins, but the relative abundance of these post-translationally modified forms is as yet unknown......, as are the consequences of the modification for the properties and turnover time of the proteins. Specific proteins appear to be particularly vulnerable to oxidative carbonylation in the matrix of plant mitochondria; these include several enzymes of the Krebs cycle, glycine decarboxylase, superoxide dismutase and heat...... shock proteins. Plant mitochondria contain a number of different proteases, but their role in removing oxidatively damaged proteins is, as yet, unclear....

  10. Bacterial infection increases risk of carcinogenesis by targeting mitochondria

    DEFF Research Database (Denmark)

    Strickertsson, Jesper A.B.; Desler, Claus; Rasmussen, Lene Juel

    2017-01-01

    pathways, and compares the impact of the bacterial alteration of mitochondrial function to that of cancer. Bacterial virulence factors have been demonstrated to induce mutations of mitochondrial DNA (mtDNA) and to modulate DNA repair pathways of the mitochondria. Furthermore, virulence factors can induce...... or impair the intrinsic apoptotic pathway. The effect of bacterial targeting of mitochondria is analogous to behavior of mitochondria in a wide array of tumours, and this strongly suggests that mitochondrial targeting of bacteria is a risk factor for carcinogenesis....

  11. Pathology of mitochondria in MELAS syndrome: an ultrastructural study.

    Science.gov (United States)

    Felczak, Paulina; Lewandowska, Eliza; Stępniak, Iwona; Ołdak, Monika; Pollak, Agnieszka; Lechowicz, Urszula; Pasennik, Elżbieta; Stępień, Tomasz; Wierzba-Bobrowicz, Teresa

    Ultrastructural changes in skeletal muscle biopsy in a 24-year-old female patient with clinically suspected mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) syndrome are presented. We observed proliferation and/or pleomorphism of mitochondria in skeletal muscle and smooth muscle cells of arterioles, as well as in pericytes of capillaries. Paracrystalline inclusions were found only in damaged mitochondria of skeletal muscle. Genetic testing revealed a point mutation in A3243G tRNALeu(UUR) typical for MELAS syndrome. We conclude that differentiated pathological changes of mitochondria in the studied types of cells may be associated with the different energy requirements of these cells.

  12. Tributyltin interacts with mitochondria and induces cytochrome c release.

    Science.gov (United States)

    Nishikimi, A; Kira, Y; Kasahara, E; Sato, E F; Kanno, T; Utsumi, K; Inoue, M

    2001-01-01

    Although triorganotins are potent inducers of apoptosis in various cell types, the critical targets of these compounds and the mechanisms by which they lead to cell death remain to be elucidated. There are two major pathways by which apoptotic cell death occurs: one is triggered by a cytokine mediator and the other is by a mitochondrion-dependent mechanism. To elucidate the mechanism of triorganotin-induced apoptosis, we studied the effect of tributyltin on mitochondrial function. We found that moderately low doses of tributyltin decrease mitochondrial membrane potential and induce cytochrome c release by a mechanism inhibited by cyclosporine A and bongkrekic acid. Tributyltin-induced cytochrome c release is also prevented by dithiols such as dithiothreitol and 2,3-dimercaptopropanol but not by monothiols such as GSH, N-acetyl-L-cysteine, L-cysteine and 2-mercaptoethanol. Further studies with phenylarsine oxide agarose revealed that tributyltin interacts with the adenine nucleotide translocator, a functional constituent of the mitochondrial permeability transition pore, which is selectively inhibited by dithiothreitol. These results suggest that, at low doses, tributyltin interacts selectively with critical thiol residues in the adenine nucleotide translocator and opens the permeability transition pore, thereby decreasing membrane potential and releasing cytochrome c from mitochondria, a series of events consistent with established mechanistic models of apoptosis. PMID:11368793

  13. DNA maintenance in plastids and mitochondria of plants

    Directory of Open Access Journals (Sweden)

    Delene J Oldenburg

    2015-10-01

    Full Text Available The DNA molecules in plastids and mitochondria of plants have been studied for over 40 years. Here, we review the data on the circular or linear form, replication, repair, and persistence of the organellar DNA (orgDNA in plants. The bacterial origin of orgDNA appears to have profoundly influenced ideas about the properties of chromosomal DNA molecules in these organelles to the point of dismissing data inconsistent with ideas from the 1970s. When found at all, circular genome-sized molecules comprise a few percent of orgDNA. In cells active in orgDNA replication, most orgDNA is found as linear and branched-linear forms larger than the size of the genome, likely a consequence of a virus-like DNA replication mechanism. In contrast to the stable chromosomal DNA molecules in bacteria and the plant nucleus, the molecular integrity of orgDNA declines during leaf development at a rate that varies among plant species. This decline is attributed to degradation of damaged-but-not-repaired molecules, with a proposed repair cost-saving benefit most evident in grasses. All orgDNA maintenance activities are proposed to occur on the nucleoid tethered to organellar membranes by developmentally-regulated proteins.

  14. Independent preferences

    DEFF Research Database (Denmark)

    Vind, Karl

    1991-01-01

    A simple mathematical result characterizing a subset of a product set is proved and used to obtain additive representations of preferences. The additivity consequences of independence assumptions are obtained for preferences which are not total or transitive. This means that most of the economic ...... theory based on additive preferences - expected utility, discounted utility - has been generalized to preferences which are not total or transitive. Other economic applications of the theorem are given...

  15. Neurosteroids: oligodendrocyte mitochondria convert cholesterol to pregnenolone

    International Nuclear Information System (INIS)

    Hu, Z.Y.; Bourreau, E.; Jung-Testas, I.; Robel, P.; Baulieu, E.E.

    1987-01-01

    Oligodendrocyte mitochondria from 21-day-old Sprague-Dawley male rats were incubated with 100 nM [ 3 H]cholesterol. It yielded [ 3 H]pregnenolone at a rate of 2.5 +/- 0.7 and 5-[ 3 H]pregnene-3β,20α-diol at a rate of 2.5 +/- 1.1 pmol per mg of protein per hr. Cultures of glial cells from 19- to 21-day-old fetuses (a mixed population of astrocytes and oligodendrocytes) were incubated for 24 hr with [ 3 H]mevalonolactone. [ 3 H]Cholesterol, [ 3 H]pregnenolone, and 5-[ 3 H]pregnene-3β,20α-diol were characterized in cellular extracts. The formation of the 3 H-labeled steroids was increased by dibutyryl cAMP (0.2 mM) added to the culture medium. The active cholesterol side-chain cleavage mechanism, recently suggested immunohistochemically and already observed in cultures of C6 glioma cells, reinforces the concept of neurosteroids applied to Δ 5 -3β-hydroxysteroids previously isolated from brain

  16. Mitochondria-targeted nutraceuticals in sports medicine: a new perspective.

    Science.gov (United States)

    Ostojic, Sergej M

    2017-01-01

    Since mitochondria have been recognized as the cells' key organelles involved in the energy utilization during exercise, targeting the organelle with specifically designed compounds (mitochondria-targeted nutraceuticals, MTNs) may have a great promise in the prevention and treatment of heavy exercise-related mitochondrial dysfunction. In vitro studies suggested that MTNs have antioxidant effects at the molecular level, and might boost mitochondrial biogenesis and organelle bioenergetics, with both processes are known to positively affect exercise performance and recovery. However, while there are a number of different MTNs evaluated for a potential benefit as a therapy for mitochondria-related diseases and conditions, only few human studies evaluated the possible impact of novel MTNs in the field of sports medicine. This mini review summarizes recent research findings regarding the efficacy of different mitochondria-targeted nutritional agents, emphasizing their roles in sports medicine.

  17. Redox conditions and protein oxidation in plant mitochondria

    DEFF Research Database (Denmark)

    Møller, Ian Max; Kasimova, Marina R.; Krab, Klaas

    2005-01-01

    Redox conditions and protein oxidation in plant mitochondria NAD(P)H has a central position in respiratory metabolism. It is produced by a large number of enzymes, e.g. the Krebs cycle dehydrogenases, in the mitochondrial matrix and is oxidised by, amongst others, the respiratory chain. Most...... of this NAD(P)H appears to be bound to proteins, in fact free NAD(P)H – an important parameter in metabolic regulation - has never been observed in mitochondria. We have estimated free and bound NAD(P)H in isolated plant mitochondria under different metabolic conditions. The fluorescence spectra of free...... and bound NADH was determined and used to deconvolute fluorescence spectra of actively respiring mitochondria. Most of the mitochondrial NADH is bound in states 2 and 4. The amount of free NADH is lower but relatively constant even increasing a little in state 3 where it is about equal to bound NADH...

  18. The destiny of Ca(2+) released by mitochondria.

    Science.gov (United States)

    Takeuchi, Ayako; Kim, Bongju; Matsuoka, Satoshi

    2015-01-01

    Mitochondrial Ca(2+) is known to regulate diverse cellular functions, for example energy production and cell death, by modulating mitochondrial dehydrogenases, inducing production of reactive oxygen species, and opening mitochondrial permeability transition pores. In addition to the action of Ca(2+) within mitochondria, Ca(2+) released from mitochondria is also important in a variety of cellular functions. In the last 5 years, the molecules responsible for mitochondrial Ca(2+) dynamics have been identified: a mitochondrial Ca(2+) uniporter (MCU), a mitochondrial Na(+)-Ca(2+) exchanger (NCLX), and a candidate for a mitochondrial H(+)-Ca(2+) exchanger (Letm1). In this review, we focus on the mitochondrial Ca(2+) release system, and discuss its physiological and pathophysiological significance. Accumulating evidence suggests that the mitochondrial Ca(2+) release system is not only crucial in maintaining mitochondrial Ca(2+) homeostasis but also participates in the Ca(2+) crosstalk between mitochondria and the plasma membrane and between mitochondria and the endoplasmic/sarcoplasmic reticulum.

  19. Characterization of DNA-binding proteins from pea mitochondria

    DEFF Research Database (Denmark)

    Hatzack, F.A.; Dombrowski, S.; Brennicke, A.

    1998-01-01

    We studied transcription initiation in the mitochondria of higher plants, with particular respect to promoter structures. Conserved elements of these promoters have been successfully identified by in vitro transcription systems in different species, whereas the involved protein components are still...

  20. SEGMENTATION OF MITOCHONDRIA IN ELECTRON MICROSCOPY IMAGES USING ALGEBRAIC CURVES.

    Science.gov (United States)

    Seyedhosseini, Mojtaba; Ellisman, Mark H; Tasdizen, Tolga

    2013-01-01

    High-resolution microscopy techniques have been used to generate large volumes of data with enough details for understanding the complex structure of the nervous system. However, automatic techniques are required to segment cells and intracellular structures in these multi-terabyte datasets and make anatomical analysis possible on a large scale. We propose a fully automated method that exploits both shape information and regional statistics to segment irregularly shaped intracellular structures such as mitochondria in electron microscopy (EM) images. The main idea is to use algebraic curves to extract shape features together with texture features from image patches. Then, these powerful features are used to learn a random forest classifier, which can predict mitochondria locations precisely. Finally, the algebraic curves together with regional information are used to segment the mitochondria at the predicted locations. We demonstrate that our method outperforms the state-of-the-art algorithms in segmentation of mitochondria in EM images.

  1. TU-F-CAMPUS-T-04: Using Gold Nanoparticles to Target Mitochondria in Radiation Therapy

    International Nuclear Information System (INIS)

    McNamara, A; McMahon, S; Lin, Y; Paganetti, H; Schuemann, J; Kuncic, Z

    2015-01-01

    Purpose: The mitochondrion, like the cell nucleus, contains genetic material and plays several critical roles that determine the cell viability, including neutralization of free radicals within the cell. Studies have shown that irradiated cells with impaired mitochondria will incur more damage to the cell nucleus. This study investigates the potential use of GNPs to enhance radiation-induced damage to the organelle. Methods: The compositions of the organelles of a JURKAT cell were determined experimentally. Using Monte Carlo simulations, we investigate the significance of dose enhancement in a monoenergetic (10–50 keV and 6 MeV) x-ray irradiated cell cytoplasm, consisting of the experimentally determined composition. We also investigate the track structure of secondary electrons in the mitochondria using Geant4-DNA in the presence and absence of GNPs for incident protons and photons. The biological effect was determined using an approach based on the local effect model, assuming the mitochondrial DNA (mtDNA) was the primary target. Results: Adding 0.01% of gold to the cell cytoplasm material can cause substantial dose enhancement, dependent on the incident x-ray energy. Track structure Monte Carlo (MC) simulations show an increased number of ionization events within the mitochondrion structure. The close proximity of GNPs to the mtDNA storing nucleoid may cause the mtDNA to receive doses above ∼100 Gy for keV x-rays, leading to mitochondrial dysfunction. Conclusion: A substantial increase in ionization events can occur in the mitochondria in the presence of GNPs. If GNPs can be delivered to tumors and attached to a sufficient number of mitochondria inside the tumor cells, mitochondrial induced cell death could be a prevalent cause of cell death. The biological structures developed here will be included in the biological MC toolkit, TOPAS-nBio

  2. Physiology of pepper fruit and the metabolism of antioxidants: chloroplasts, mitochondria and peroxisomes

    Science.gov (United States)

    Palma, José M.; Sevilla, Francisca; Jiménez, Ana; del Río, Luis A.; Corpas, Francisco J.; Álvarez de Morales, Paz; Camejo, Daymi M.

    2015-01-01

    Background and Aims Pepper (Capsicum annuum) contains high levels of antioxidants, such as vitamins A and C and flavonoids. However, information on the role of these beneficial compounds in the physiology of pepper fruit remains scarce. Recent studies have shown that antioxidants in ripe pepper fruit play a key role in responses to temperature changes, and the redox state at the time of harvest affects the nutritional value for human consumption. In this paper, the role of antioxidant metabolism of pepper fruit during ripening and in the response to low temperature is addressed, paying particular attention to ascorbate, NADPH and the superoxide dismutase enzymatic system. The participation of chloroplasts, mitochondria and peroxisomes in the ripening process is also investigated. Scope and Results Important changes occur at a subcellular level during ripening of pepper fruit. Chloroplasts turn into chromoplasts, with drastic conversion of their metabolism, and the role of the ascorbate–glutathione cycle is essential. In mitochondria from red fruits, higher ascorbate peroxidase (APX) and Mn-SOD activities are involved in avoiding the accumulation of reactive oxygen species in these organelles during ripening. Peroxisomes, whose antioxidant capacity at fruit ripening is substantially affected, display an atypical metabolic pattern during this physiological stage. In spite of these differences observed in the antioxidative metabolism of mitochondria and peroxisomes, proteomic analysis of these organelles, carried out by 2-D electrophoresis and MALDI-TOF/TOF and provided here for the first time, reveals no changes between the antioxidant metabolism from immature (green) and ripe (red) fruits. Conclusions Taken together, the results show that investigation of molecular and enzymatic antioxidants from cell compartments, especially chloroplasts, mitochondria and peroxisomes, is a useful tool to study the physiology of pepper fruit, particularly in the context of

  3. TU-F-CAMPUS-T-04: Using Gold Nanoparticles to Target Mitochondria in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, A [Massachusetts General Hospital & Harvard Med. Sch., Boston, MA (United States); McMahon, S [Massachusetts General Hospital, Boston, Ma (United States); Lin, Y [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Paganetti, H; Schuemann, J [Massachusetts General Hospital, Boston, MA (United States); Kuncic, Z [University of Sydney, Sydney, NSW (Australia)

    2015-06-15

    Purpose: The mitochondrion, like the cell nucleus, contains genetic material and plays several critical roles that determine the cell viability, including neutralization of free radicals within the cell. Studies have shown that irradiated cells with impaired mitochondria will incur more damage to the cell nucleus. This study investigates the potential use of GNPs to enhance radiation-induced damage to the organelle. Methods: The compositions of the organelles of a JURKAT cell were determined experimentally. Using Monte Carlo simulations, we investigate the significance of dose enhancement in a monoenergetic (10–50 keV and 6 MeV) x-ray irradiated cell cytoplasm, consisting of the experimentally determined composition. We also investigate the track structure of secondary electrons in the mitochondria using Geant4-DNA in the presence and absence of GNPs for incident protons and photons. The biological effect was determined using an approach based on the local effect model, assuming the mitochondrial DNA (mtDNA) was the primary target. Results: Adding 0.01% of gold to the cell cytoplasm material can cause substantial dose enhancement, dependent on the incident x-ray energy. Track structure Monte Carlo (MC) simulations show an increased number of ionization events within the mitochondrion structure. The close proximity of GNPs to the mtDNA storing nucleoid may cause the mtDNA to receive doses above ∼100 Gy for keV x-rays, leading to mitochondrial dysfunction. Conclusion: A substantial increase in ionization events can occur in the mitochondria in the presence of GNPs. If GNPs can be delivered to tumors and attached to a sufficient number of mitochondria inside the tumor cells, mitochondrial induced cell death could be a prevalent cause of cell death. The biological structures developed here will be included in the biological MC toolkit, TOPAS-nBio.

  4. Oxidoreductive capability of boar sperm mitochondria in fresh semen and during their preservation in BTS extender.

    Science.gov (United States)

    Gaczarzewicz, Dariusz; Piasecka, Małgorzata; Udała, Jan; Błaszczyk, Barbara; Laszczyńska, Maria; Kram, Andrzej

    2003-07-01

    The purpose of our study was to determine the effect of dilution and liquid-preservation of boar sperm on oxidoreductive capability of their mitochondria. The semen was diluted with BTS extender produced from water purified by destillation or by reverse osmosis. The spermatozoa were stored over a four-day period at 16-18 degrees C. The function of sperm mitochondria was assessed using the screening cytochemical test for NADH-dependent oxidoreductases (diaphorase/NADH, related to flavoprotein). Morphological assessment of cytochemical reaction was carried out using a light microscope. The intensity of the reaction was evaluated by means of a computer image analysing system (Quantimet 600S), measuring the integrated optical density (IOD) and mean optical density (MOD) of the reaction product (formazans) occurring in the sperm midpieces. In the non-diluted semen, intensive cytochemical reaction throughout the length of the sperm midpiece was observed. Furthermore, spermatozoa with the intensive reaction displayed the high optical density values. After dilution the semen with two variants of experimental extender, and as the conservation time expired, the cytochemical reaction was less intensive. Moreover, the absence of formazan deposits in various parts of the sperm midpiece was also noted. These morphological features corresponded to low values of optical density. These findings suggest that the dilution of semen and the time of sperm preservation may be critical factors that handicap energy metabolism of sperm mitochondria. The type of water used in preparing BTS extender does not have any significant effect on the oxidoreductive capability of sperm boar mitochondria.

  5. WHITE PANICLE3, a Novel Nucleus-Encoded Mitochondrial Protein, Is Essential for Proper Development and Maintenance of Chloroplasts and Mitochondria in Rice

    Directory of Open Access Journals (Sweden)

    Hongchang Li

    2018-06-01

    Full Text Available Mitochondria and chloroplasts are interacting organelles that play important roles in plant development. In addition to a small number proteins encoded by their own genomes, the majority of mitochondrial and chloroplast proteins are encoded in the cell nucleus and imported into the organelle. As a consequence, coordination between mitochondria, chloroplasts, and the nucleus is of crucial importance to plant cells. Variegated mutants are chloroplast-defective mutants and are considered to be ideal models for studying the intercommunication between these organelles. Here, we report the isolation of WHITE PANICLE3 (WP3, a nuclear gene involved in variegation, from a naturally occurring white panicle rice mutant. Disrupted expression of WP3 in the mutant leads to severe developmental defects in both chloroplasts and mitochondria, and consequently causes the appearance of white-striped leaves and white panicles in the mutant plants. Further investigation showed that WP3 encodes a protein most likely targeted to mitochondria and is specifically expressed in rice panicles. Interestingly, we demonstrate that the recessive white-panicle phenotype in the wp3 mutant is inherited in a typical Mendelian manner, while the white-striped leaf phenotype in wp3 is maternally inherited. Our data collectively suggest that the nucleus-encoded mitochondrial protein, WP3, plays an essential role in the regulation of chloroplast development in rice panicles by maintaining functional mitochondria. Therefore, the wp3 mutant is an excellent model in which to explore the communication between the nucleus, mitochondria, and chloroplasts in plant cells.

  6. The rhizome of Reclinomonas americana, Homo sapiens, Pediculus humanus and Saccharomyces cerevisiae mitochondria

    Directory of Open Access Journals (Sweden)

    Raoult Didier

    2011-10-01

    Full Text Available Abstract Background Mitochondria are thought to have evolved from eubacteria-like endosymbionts; however, the origin of the mitochondrion remains a subject of debate. In this study, we investigated the phenomenon of chimerism in mitochondria to shed light on the origin of these organelles by determining which species played a role in their formation. We used the mitochondria of four distinct organisms, Reclinomonas americana, Homo sapiens, Saccharomyces cerevisiae and multichromosome Pediculus humanus, and attempted to identify the origin of each mitochondrial gene. Results Our results suggest that the origin of mitochondrial genes is not limited to the Rickettsiales and that the creation of these genes did not occur in a single event, but through multiple successive events. Some of these events are very old and were followed by events that are more recent and occurred through the addition of elements originating from current species. The points in time that the elements were added and the parental species of each gene in the mitochondrial genome are different to the individual species. These data constitute strong evidence that mitochondria do not have a single common ancestor but likely have numerous ancestors, including proto-Rickettsiales, proto-Rhizobiales and proto-Alphaproteobacteria, as well as current alphaproteobacterial species. The analysis of the multichromosome P. humanus mitochondrion supports this mechanism. Conclusions The most plausible scenario of the origin of the mitochondrion is that ancestors of Rickettsiales and Rhizobiales merged in a proto-eukaryotic cell approximately one billion years ago. The fusion of the Rickettsiales and Rhizobiales cells was followed by gene loss, genomic rearrangements and the addition of alphaproteobacterial elements through ancient and more recent recombination events. Each gene of each of the four studied mitochondria has a different origin, while in some cases, multichromosomes may allow for

  7. Repercussion of mitochondria deformity induced by anti-Hsp90 drug 17AAG in human tumor cells

    KAUST Repository

    Vishal, Chaturvedi

    2011-06-07

    Inhibiting Hsp90 chaperone roles using 17AAG induces cytostasis or apoptosis in tumor cells through destabilization of several mutated cancer promoting proteins. Although mitochondria are central in deciding the fate of cells, 17AAG induced effects on tumor cell mitochondria were largely unknown. Here, we show that Hsp90 inhibition with 17AAG first affects mitochondrial integrity in different human tumor cells, neuroblastoma, cervical cancer and glial cells. Using human neuroblastoma tumor cells, we found the early effects associated with a change in mitochondrial membrane potential, elongation and engorgement of mitochondria because of an increased matrix vacuolization. These effects are specific to Hsp90 inhibition as other chemotherapeutic drugs did not induce similar mitochondrial deformity. Further, the effects are independent of oxidative damage and cytoarchitecture destabilization since cytoskeletal disruptors and mitochondrial metabolic inhibitors also do not induce similar deformity induced by 17AAG. The 1D PAGE LC MS/ MS mitochondrial proteome analysis of 17AAG treated human neuroblastoma cells showed a loss of 61% proteins from membrane, metabolic, chaperone and ribonucleoprotein families. About 31 unmapped protein IDs were identified from proteolytic processing map using Swiss-Prot accession number, and converted to the matching gene name searching the ExPASy proteomics server. Our studies display that Hsp90 inhibition effects at first embark on mitochondria of tumor cells and compromise mitochondrial integrity. the author(s), publisher and licensee Libertas Academica Ltd.

  8. The Evolutionary History of MAPL (Mitochondria-Associated Protein Ligase and Other Eukaryotic BAM/GIDE Domain Proteins.

    Directory of Open Access Journals (Sweden)

    Jeremy G Wideman

    Full Text Available MAPL (mitochondria-associated protein ligase, also called MULAN/GIDE/MUL1 is a multifunctional mitochondrial outer membrane protein found in human cells that contains a unique BAM (beside a membrane domain and a C-terminal RING-finger domain. MAPL has been implicated in several processes that occur in animal cells such as NF-kB activation, innate immunity and antiviral signaling, suppression of PINK1/parkin defects, mitophagy in skeletal muscle, and caspase-dependent apoptosis. Previous studies demonstrated that the BAM domain is present in diverse organisms in which most of these processes do not occur, including plants, archaea, and bacteria. Thus the conserved function of MAPL and its BAM domain remains an open question. In order to gain insight into its conserved function, we investigated the evolutionary origins of MAPL by searching for homologues in predicted proteomes of diverse eukaryotes. We show that MAPL proteins with a conserved BAM-RING architecture are present in most animals, protists closely related to animals, a single species of fungus, and several multicellular plants and related green algae. Phylogenetic analysis demonstrated that eukaryotic MAPL proteins originate from a common ancestor and not from independent horizontal gene transfers from bacteria. We also determined that two independent duplications of MAPL occurred, one at the base of multicellular plants and another at the base of vertebrates. Although no other eukaryote genome examined contained a verifiable MAPL orthologue, BAM domain-containing proteins were identified in the protists Bigelowiella natans and Ectocarpus siliculosis. Phylogenetic analyses demonstrated that these proteins are more closely related to prokaryotic BAM proteins and therefore likely arose from independent horizontal gene transfers from bacteria. We conclude that MAPL proteins with BAM-RING architectures have been present in the holozoan and viridiplantae lineages since their very beginnings

  9. Independent Directors

    DEFF Research Database (Denmark)

    Ringe, Wolf-Georg

    2013-01-01

    This paper re-evaluates the corporate governance concept of ‘board independence’ against the disappointing experiences during the 2007-08 financial crisis. Independent or outside directors had long been seen as an essential tool to improve the monitoring role of the board. Yet the crisis revealed...... that they did not prevent firms' excessive risk taking; further, these directors sometimes showed serious deficits in understanding the business they were supposed to control, and remained passive in addressing structural problems. A closer look reveals that under the surface of seemingly unanimous consensus...

  10. Mitochondria and Mitochondrial ROS in Cancer: Novel Targets for Anticancer Therapy.

    Science.gov (United States)

    Yang, Yuhui; Karakhanova, Svetlana; Hartwig, Werner; D'Haese, Jan G; Philippov, Pavel P; Werner, Jens; Bazhin, Alexandr V

    2016-12-01

    Mitochondria are indispensable for energy metabolism, apoptosis regulation, and cell signaling. Mitochondria in malignant cells differ structurally and functionally from those in normal cells and participate actively in metabolic reprogramming. Mitochondria in cancer cells are characterized by reactive oxygen species (ROS) overproduction, which promotes cancer development by inducing genomic instability, modifying gene expression, and participating in signaling pathways. Mitochondrial and nuclear DNA mutations caused by oxidative damage that impair the oxidative phosphorylation process will result in further mitochondrial ROS production, completing the "vicious cycle" between mitochondria, ROS, genomic instability, and cancer development. The multiple essential roles of mitochondria have been utilized for designing novel mitochondria-targeted anticancer agents. Selective drug delivery to mitochondria helps to increase specificity and reduce toxicity of these agents. In order to reduce mitochondrial ROS production, mitochondria-targeted antioxidants can specifically accumulate in mitochondria by affiliating to a lipophilic penetrating cation and prevent mitochondria from oxidative damage. In consistence with the oncogenic role of ROS, mitochondria-targeted antioxidants are found to be effective in cancer prevention and anticancer therapy. A better understanding of the role played by mitochondria in cancer development will help to reveal more therapeutic targets, and will help to increase the activity and selectivity of mitochondria-targeted anticancer drugs. In this review we summarized the impact of mitochondria on cancer and gave summary about the possibilities to target mitochondria for anticancer therapies. J. Cell. Physiol. 231: 2570-2581, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Amino acid codes in mitochondria as possible clues to primitive codes

    Science.gov (United States)

    Jukes, T. H.

    1981-01-01

    Differences between mitochondrial codes and the universal code indicate that an evolutionary simplification has taken place, rather than a return to a more primitive code. However, these differences make it evident that the universal code is not the only code possible, and therefore earlier codes may have differed markedly from the previous code. The present universal code is probably a 'frozen accident.' The change in CUN codons from leucine to threonine (Neurospora vs. yeast mitochondria) indicates that neutral or near-neutral changes occurred in the corresponding proteins when this code change took place, caused presumably by a mutation in a tRNA gene.

  12. Mitochondria: 3-bromopyruvate vs. mitochondria? A small molecule that attacks tumors by targeting their bioenergetic diversity.

    Science.gov (United States)

    Galina, Antonio

    2014-09-01

    Enhanced glycolysis, the classic bioenergetic phenotype of cancer cells was described by Otto Warburg approximately 90 years ago. However, the Warburg hypothesis does not necessarily imply mitochondrial dysfunction. The alkyl-halogen, 3-bromopyruvate (3BP), would not be expected to have selective targets for cancer therapy due to its high potential reactivity toward many SH side groups. Contrary to predictions, 3BP interferes with glycolysis and oxidative phosphorylation in cancer cells without side effects in normal tissues. The mitochondrial hexokinase II has been claimed as the main target. This "Organelle in focus" article presents a historical view of the use of 3BP in biochemistry and its effects on ATP-producing pathways of cancer cells. I will discuss how the alkylated enzymes contribute to the cooperative collapse of mitochondria and apoptosis. Perspectives for targeting 3BP to bioenergetics enzymes for cancer treatment will be considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Fluoxetine and the mitochondria: A review of the toxicological aspects.

    Science.gov (United States)

    de Oliveira, Marcos Roberto

    2016-09-06

    Fluoxetine (a selective serotonin reuptake inhibitor (SSRI)) is used as an antidepressant by modulating the levels of serotonin in the synaptic cleft. Nevertheless, fluoxetine also induces undesirable effects, such as anxiety, sexual dysfunction, sleep disturbances, and gastrointestinal impairments. Fluoxetine has been viewed as an agent that may interfere with cell fate by triggering apoptosis. On the other hand, fluoxetine intake has been associated with increased cancer risk. Nonetheless, data remain contradictory and no conclusions were taken. Several studies demonstrated that fluoxetine interacts with mitochondria triggering apoptosis and/or altering mitochondrial function by modulating the activity of respiratory chain components and enzymes of the Krebs cycle. Furthermore, fluoxetine affects mitochondria-related redox parameters in different experimental models. In this review, data demonstrating the effects of fluoxetine upon mammalian mitochondria are described and discussed, as well as several unsolved questions in this field of research are addressed. A separate section deals with future needs regarding the research involving the impact of fluoxetine treatment upon mitochondria and mitochondria-related signaling. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. CA V is present in rat kidney mitochondria

    International Nuclear Information System (INIS)

    Dodgson, S.J.; Contino, L.C.

    1987-01-01

    Guinea pig liver mitochondria contain the unique carbonic anhydrase isozyme, CA V. Prior to sacrifice, 15 rats and 15 guinea pigs were either fed normal lab chow (group 1), starved 48 hours (group 2) or fed normal lab chow and given to drink only water with added HCl, pH 2.5 (group 3). Mitochondria were prepared from excised livers and kidneys. CA V activity of disrupted mitochondria was measured by 18 O-mass spectrometric technique at pH 7.4, 37 0 C, 25 mM NaHCO 3 . Mass spectrometric CA assays with intact kidney mitochondria localize CA V activity to the matrix, as was found for liver mitochondria. It has been shown in hepatocytes prepared from starved guinea pigs and rats that inhibition of CA V results in decreased rate of gluconeogenesis from pyruvate. These present results are in line with the published observation that rat kidneys are much more gluconeogenic than guinea pig, and that this is increased by starvation and acidosis

  15. Are mitochondria a permanent source of reactive oxygen species?

    Science.gov (United States)

    Staniek, K; Nohl, H

    2000-11-20

    The observation that in isolated mitochondria electrons may leak out of the respiratory chain to form superoxide radicals (O(2)(radical-)) has prompted the assumption that O(2)(radical-) formation is a compulsory by-product of respiration. Since mitochondrial O(2)(radical-) formation under homeostatic conditions could not be demonstrated in situ so far, conclusions drawn from isolated mitochondria must be considered with precaution. The present study reveals a link between electron deviation from the respiratory chain to oxygen and the coupling state in the presence of antimycin A. Another important factor is the analytical system applied for the detection of activated oxygen species. Due to the presence of superoxide dismutase in mitochondria, O(2)(radical-) release cannot be realistically determined in intact mitochondria. We therefore followed the release of the stable dismutation product H(2)O(2) by comparing most frequently used H(2)O(2) detection methods. The possible interaction of the detection systems with the respiratory chain was avoided by a recently developed method, which was compared with conventional methods. Irrespective of the methods applied, the substrates used for respiration and the state of respiration established, intact mitochondria could not be made to release H(2)O(2) from dismutating O(2)(radical-). Although regular mitochondrial respiration is unlikely to supply single electrons for O(2)(radical-) formation our study does not exclude the possibility of the respiratory chain becoming a radical source under certain conditions.

  16. Ca2+-associated triphasic pH changes in mitochondria during brown adipocyte activation.

    Science.gov (United States)

    Hou, Yanyan; Kitaguchi, Tetsuya; Kriszt, Rókus; Tseng, Yu-Hua; Raghunath, Michael; Suzuki, Madoka

    2017-08-01

    Brown adipocytes (BAs) are endowed with a high metabolic capacity for energy expenditure due to their high mitochondria content. While mitochondrial pH is dynamically regulated in response to stimulation and, in return, affects various metabolic processes, how mitochondrial pH is regulated during adrenergic stimulation-induced thermogenesis is unknown. We aimed to reveal the spatial and temporal dynamics of mitochondrial pH in stimulated BAs and the mechanisms behind the dynamic pH changes. A mitochondrial targeted pH-sensitive protein, mito-pHluorin, was constructed and transfected to BAs. Transfected BAs were stimulated by an adrenergic agonist, isoproterenol. The pH changes in mitochondria were characterized by dual-color imaging with indicators that monitor mitochondrial membrane potential and heat production. The mechanisms of pH changes were studied by examining the involvement of electron transport chain (ETC) activity and Ca 2+ profiles in mitochondria and the intracellular Ca 2+ store, the endoplasmic reticulum (ER). A triphasic mitochondrial pH change in BAs upon adrenergic stimulation was revealed. In comparison to a thermosensitive dye, we reveal that phases 1 and 2 of the pH increase precede thermogenesis, while phase 3, characterized by a pH decrease, occurs during thermogenesis. The mechanism of pH increase is partially related to ETC. In addition, the pH increase occurs concurrently with an increase in mitochondrial Ca 2+ . This Ca 2+ increase is contributed to by an influx from the ER, and it is further involved in mitochondrial pH regulation. We demonstrate that an increase in mitochondrial pH is implicated as an early event in adrenergically stimulated BAs. We further suggest that this pH increase may play a role in the potentiation of thermogenesis.

  17. Oxidation mechanisms occurring in wines

    OpenAIRE

    Oliveira, Carla Maria; Ferreira, António César Silva; Freitas, Victor De; Silva, Artur M. S.

    2011-01-01

    The present review aims to show the state of the art on the oxidation mechanisms occurring in wines, as well as the methods to monitor, classify and diagnose wine oxidation. Wine oxidation can be divided in enzymatic oxidation and non-enzymatic oxidation. Enzymatic oxidation almost entirely occurs in grape must and is largely correlated with the content of hydroxycinnamates, such as caffeoyltartaric acid and paracoumaroyltartaric acid, and flavan-3-ols. Non-enzymatic oxidation, al...

  18. Aspirin Induces Apoptosis through Release of Cytochrome c from Mitochondria

    Directory of Open Access Journals (Sweden)

    Katja C. Zimmermann

    2000-01-01

    Full Text Available Nonsteroidal anti-inflammatory drugs (NSAID reduce the risk for cancer, due to their anti proliferative and apoptosis-inducing effects. A critical pathway for apoptosis involves the release of cytochrome c from mitochondria, which then interacts with Apaf-1 to activate caspase proteases that orchestrate cell death. In this study we found that treatment of a human cancer cell line with aspirin induced caspase activation and the apoptotic cell morphology, which was blocked by the caspase inhibitor zVAD-fmk. Further analysis of the mechanism underlying this apoptotic event showed that aspirin induces translocation of Bax to the mitochondria and triggers release of cytochrome c into the cytosol. The release of cytochrome c from mitochondria was inhibited by overexpression of the antiapoptotic protein Bcl-2 and cells that lack Apaf-1 were resistant to aspirin-induced apoptosis. These data provide evidence that the release of cytochrome c is an important part of the apoptotic mechanism of aspirin.

  19. Doxorubicin Action on Mitochondria: Relevance to Osteosarcoma Therapy?

    Science.gov (United States)

    Armstrong, Jo; Dass, Crispin R

    2018-01-01

    The mitochondria may very well determine the final commitment of the cell to death, particularly in times of energy stress. Cancer chemotherapeutics such as the anthracycline doxorubicin perturb mitochondrial structure and function in tumour cells, as evidenced in osteosarcoma, for which doxorubicin is used clinically as frontline therapy. This same mechanism of cell inhibition is also pertinent to doxorubicin's primary cause of side-effects, that to the cardiac tissue, culminating in such dire events as congestive heart failure. Reactive oxygen species are partly to blame for this effect on the mitochondria, which impact the electron transport chain. As this review highlights that, there is much more to be learnt about the mitochondria and how it is affected by such effective but toxic drugs as doxorubicin. Such information will aid researchers who search for cancer treatment able to preserve mitochondrial number and function in normal cells. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. [Organization of mitochondria in the growing hyphae of Neurospora crassa].

    Science.gov (United States)

    Potapova, T V; Boĭtsova, L Iu; Golyshev, S A; Popinako, A V

    2013-01-01

    In vivo fluorescent labeling of mitochondria in Neurospora crassa showed the concentration of filamentous mitochondria within 30 μm of apex in growing hyphae. These mitochondrial assemblies propagated forward with the elongation of hyphae, split and segregated as the growing tip bifurcated and formed de novo when new branches formed farther away from the apex. The efficiency of the mitochondria concentration in the apical 30 μm zone is related to the growth rate and identical in hyphae cultivated in glucose- and sorbitol-containing media. The obtained data are discussed in connection with the behavior of microtubules in growing hyphae as well as with the electric heterogeneity of N. crassa hyphal apex described previously.

  1. RECQL4 localizes to mitochondria and preserves mitochondrial DNA integrity

    DEFF Research Database (Denmark)

    Croteau, Deborah L; Rossi, Marie L; Canugovi, Chandrika

    2012-01-01

    in premature aging. There is no information about whether any of the RecQ helicases play roles in mitochondrial biogenesis, which is strongly implicated in the aging process. Here, we used microscopy to visualize RECQL4 in mitochondria. Fractionation of human and mouse cells also showed that RECQL4 was present...... in mitochondria. Q-PCR amplification of mitochondrial DNA demonstrated that mtDNA damage accumulated in RECQL4-deficient cells. Microarray analysis suggested that mitochondrial bioenergetic pathways might be affected in RTS. Measurements of mitochondrial bioenergetics showed a reduction in the mitochondrial......Q helicase to be found in both human and mouse mitochondria, and the loss of RECQL4 alters mitochondrial integrity....

  2. Chatty Mitochondria: Keeping Balance in Cellular Protein Homeostasis.

    Science.gov (United States)

    Topf, Ulrike; Wrobel, Lidia; Chacinska, Agnieszka

    2016-08-01

    Mitochondria are multifunctional cellular organelles that host many biochemical pathways including oxidative phosphorylation (OXPHOS). Defective mitochondria pose a threat to cellular homeostasis and compensatory responses exist to curtail the source of stress and/or its consequences. The mitochondrial proteome comprises proteins encoded by the nuclear and mitochondrial genomes. Disturbances in protein homeostasis may originate from mistargeting of nuclear encoded mitochondrial proteins. Defective protein import and accumulation of mistargeted proteins leads to stress that triggers translation alterations and proteasomal activation. These cytosolic pathways are complementary to the mitochondrial unfolded protein response (UPRmt) that aims to increase the capacity of protein quality control mechanisms inside mitochondria. They constitute putative targets for interventions aimed at increasing the fitness, stress resistance, and longevity of cells and organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Mitochondria As the Target for the Modulatory Effect of Curcumin in Oxaliplatin-induced Toxicity in Isolated Rat Liver Mitochondria.

    Science.gov (United States)

    Waseem, Mohammad; Parvez, Suhel; Tabassum, Heena

    2017-01-01

    To explore hepatoprotective action of curcumin (CMN, a bioflavonoid) on oxaliplatin (Oxa)-triggered mitochondrial oxidative stress and respiratory chain complexes in liver of rats. Oxa is a ubiquitously utilized platinum-based chemotherapeutic agent commonly used for the treatment of colorectal cancer. Mitochondria have recently emerged as targets for anticancer drugs in several kinds of toxicity including hepatotoxicity that can lead to neoplastic disease. There is a dearth of evidence involving the role of mitochondria in mediating Oxa-evoked hepatotoxicity and its underlying mechanism is still debatable. The study was performed in mitochondria isolated from liver of Wistar rats. Oxa (200 μg/mL) and CMN (5 μmol) were incubated under in vitro conditions. Oxa evoked a significant increase in the membrane lipid peroxidation (LPO) levels, protein carbonyl (PC) contents, decrease in reduced glutathione (GSH) and nonprotein thiol (NP-SH) levels. Oxa also caused a marked decline in the activities of enzymatic antioxidants and respiratory chain enzymes (I, II, III and V) in liver mitochondria. CMN pre-treatment significantly prevented the activities of enzymatic antioxidants and mitochondrial respiratory chain enzymes. CMN also restored the LPO and PC contents, GSH and NP-SH levels in liver mitochondria. CMN intake might be effective in regulation of Oxa-evoked mitotoxicity during chemotherapy. Moreover, it is included in the armamentarium for anticancer agent-induced oxidative stress. Copyright © 2017 IMSS. Published by Elsevier Inc. All rights reserved.

  4. Alkyladenine DNA glycosylase (AAG) localizes to mitochondria and interacts with mitochondrial single-stranded binding protein (mtSSB).

    Science.gov (United States)

    van Loon, Barbara; Samson, Leona D

    2013-03-01

    Due to a harsh environment mitochondrial genomes accumulate high levels of DNA damage, in particular oxidation, hydrolytic deamination, and alkylation adducts. While repair of alkylated bases in nuclear DNA has been explored in detail, much less is known about the repair of DNA alkylation damage in mitochondria. Alkyladenine DNA glycosylase (AAG) recognizes and removes numerous alkylated bases, but to date AAG has only been detected in the nucleus, even though mammalian mitochondria are known to repair DNA lesions that are specific substrates of AAG. Here we use immunofluorescence to show that AAG localizes to mitochondria, and we find that native AAG is present in purified human mitochondrial extracts, as well as that exposure to alkylating agent promotes AAG accumulation in the mitochondria. We identify mitochondrial single-stranded binding protein (mtSSB) as a novel interacting partner of AAG; interaction between mtSSB and AAG is direct and increases upon methyl methanesulfonate (MMS) treatment. The consequence of this interaction is specific inhibition of AAG glycosylase activity in the context of a single-stranded DNA (ssDNA), but not a double-stranded DNA (dsDNA) substrate. By inhibiting AAG-initiated processing of damaged bases, mtSSB potentially prevents formation of DNA breaks in ssDNA, ensuring that base removal primarily occurs in dsDNA. In summary, our findings suggest the existence of AAG-initiated BER in mitochondria and further support a role for mtSSB in DNA repair. Copyright © 2012. Published by Elsevier B.V.

  5. Reciprocal enhancement of uptake and toxicity of cadmium and calcium in rainbow trout (Oncorhynchus mykiss) liver mitochondria

    International Nuclear Information System (INIS)

    Adiele, Reginald C.; Stevens, Don; Kamunde, Collins

    2010-01-01

    The interactive effects of cadmium (Cd) and calcium (Ca) on energy metabolism in rainbow trout liver mitochondria were studied to test the prediction that Ca would protect against Cd-induced mitochondrial liability. Isolated rainbow trout liver mitochondria were energized with malate and glutamate and exposed to increasing concentrations (5-100 μM) of Cd and Ca singly and in combination at 15 o C. Accumulation of Cd and Ca in the mitochondria and mitochondrial respiration (oxygen consumption) rates were measured. Additionally, un-energized mitochondria were incubated with low doses (1 μM) of Cd and Ca singly and in combination, with time-course measurements of cation accumulation/binding and oxygen consumption rates. In energized actively phosphorylating mitochondria, the uptake rates of both Cd and Ca were dose-dependent and enhanced when administered concurrently. Upon low-dose incubation, Cd accumulation was rapid and peaked in 5 min, while no appreciable uptake of Ca occurred. Functionally, the resting (state 4, ADP-limited) respiration rate was not affected in the dose-response exposure, but it decreased remarkably on low-dose incubation. Adenosine diphosphate (ADP)-stimulated respiration (state 3) rate was impaired dose-dependently with maximal inhibitions (at the highest dose, 100 μM) of 32, 64 and 73% for Ca, Cd, and combined exposures, respectively. The combined effects of Ca and Cd suggested synergistic (more than additive) action and partial additivity of effects at low and higher doses of the two cations, respectively. Moreover, on a molar basis, Cd was twice as toxic as Ca to rainbow trout liver mitochondria and when combined, approximately 90% of the effects were attributable to Cd. The coupling efficiency, as measured by respiratory control ratio (RCR) and phosphorylation efficiency, measured as ADP/O ratio, both decreased as the exposure dosage and duration increased. In addition, Cd and Ca exposure decreased mitochondrial proton leak (state 4

  6. New nanocomposites for SERS studies of living cells and mitochondria

    DEFF Research Database (Denmark)

    Sarycheva, A. S.; Brazhe, N. A.; Baizhumanov, A. A.

    2016-01-01

    A great enhancement in Raman scattering (SERS) from heme-containing submembrane biomolecules inside intact erythrocytes and functional mitochondria is demonstrated for the first time using silver–silica beads prepared using a new method involving aerosol pyrolysis with aqueous diamminesilver...... molecules. The SERS spectra of functional mitochondria are sensitive to the activity of the mitochondrial electron transport chain, thus making the method a novel label-free approach to monitor the redox state and conformation of cytochromes in their natural cell environment. The developed nanocomposites...

  7. Influence of Pulsed Electric Fields and Mitochondria-Cytoskeleton Interactions on Cell Respiration.

    Science.gov (United States)

    Goswami, Ishan; Perry, Justin B; Allen, Mitchell E; Brown, David A; von Spakovsky, Michael R; Verbridge, Scott S

    2018-06-19

    Pulsed electric fields with microsecond pulse width (μsPEFs) are used clinically; namely, irreversible electroporation/Nanoknife is used for soft tissue tumor ablation. The μsPEF pulse parameters used in irreversible electroporation (0.5-1 kV/cm, 80-100 pulses, ∼100 μs each, 1 Hz frequency) may cause an internal field to develop within the cell because of the disruption of the outer cell membrane and subsequent penetration of the electric field. An internal field may disrupt voltage-sensitive mitochondria, although the research literature has been relatively unclear regarding whether such disruptions occur with μsPEFs. This investigation reports the influence of clinically used μsPEF parameters on mitochondrial respiration in live cells. Using a high-throughput Agilent Seahorse machine, it was observed that μsPEF exposure comprising 80 pulses with amplitudes of 600 or 700 V/cm did not alter mitochondrial respiration in 4T1 cells measured after overnight postexposure recovery. To record alterations in mitochondrial function immediately after μsPEF exposure, high-resolution respirometry was used to measure the electron transport chain state via responses to glutamate-malate and ADP and mitochondrial membrane potential via response to carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. In addition to measuring immediate mitochondrial responses to μsPEF exposure, measurements were also made on cells permeabilized using digitonin and those with compromised cytoskeleton due to actin depolymerization via treatment with the drug latrunculin B. The former treatment was used as a control to tease out the effects of plasma membrane permeabilization, whereas the latter was used to investigate indirect effects on the mitochondria that may occur if μsPEFs impact the cytoskeleton on which the mitochondria are anchored. Based on the results, it was concluded that within the pulse parameters tested, μsPEFs alone do not hinder mitochondrial physiology but can be used

  8. Erythroid precursors from patients with low-risk myelodysplasia demonstrate ultrastructural features of enhanced autophagy of mitochondria

    NARCIS (Netherlands)

    Houwerzijl, E. J.; Pol, H-W D.; Blom, N. R.; van der Want, J. J. L.; de Wolf, J. Thm; Vellenga, E.

    Recent studies in erythroid cells have shown that autophagy is an important process for the physiological clearance of mitochondria during terminal differentiation. However, autophagy also plays an important role in removing damaged and dysfunctional mitochondria. Defective mitochondria and impaired

  9. Leber-opticusatrofie; een mitochondriaal overervende ziekte

    NARCIS (Netherlands)

    Oostra, R. J.; Bolhuis, P. A.; Wijburg, F. A.; Bleeker-Wagemakers, E. M.

    1995-01-01

    Leber hereditary optic neuropathy (LHON) is a heritable disorder, clinically characterized by rapidly progressive loss of central vision due to severe bilateral optic atrophy. The disease predominantly occurs in men. The clinical picture shows marked interpersonal variation. Recently it has been

  10. NSAIDs, Mitochondria and Calcium Signaling: Special Focus on Aspirin/Salicylates

    Directory of Open Access Journals (Sweden)

    Yoshihiro Suzuki

    2010-05-01

    Full Text Available Aspirin (acetylsalicylic acid is a well-known nonsteroidal anti-inflammatory drug (NSAID that has long been used as an anti-pyretic and analgesic drug. Recently, much attention has been paid to the chemopreventive and apoptosis-inducing effects of NSAIDs in cancer cells. These effects have been thought to be primarily attributed to the inhibition of cyclooxygenase activity and prostaglandin synthesis. However, recent studies have demonstrated unequivocally that certain NSAIDs, including aspirin and its metabolite salicylic acid, exert their anti-inflammatory and chemopreventive effects independently of cyclooxygenase activity and prostaglandin synthesis inhibition. It is becoming increasingly evident that two potential common targets of NSAIDs are mitochondria and the Ca2+ signaling pathway. In this review, we provide an overview of the current knowledge regarding the roles of mitochondria and Ca2+ in the apoptosis-inducing effects as well as some side effects of aspirin, salicylates and other NSAIDs, and introducing the emerging role of L-type Ca2+ channels, a new Ca2+ entry pathway in non-excitable cells that is up-regulated in human cancer cells.

  11. Ceramide-Induced Apoptosis in Renal Tubular Cells: A Role of Mitochondria and Sphingosine-1-Phoshate

    Science.gov (United States)

    Ueda, Norishi

    2015-01-01

    Ceramide is synthesized upon stimuli, and induces apoptosis in renal tubular cells (RTCs). Sphingosine-1 phosphate (S1P) functions as a survival factor. Thus, the balance of ceramide/S1P determines ceramide-induced apoptosis. Mitochondria play a key role for ceramide-induced apoptosis by altered mitochondrial outer membrane permeability (MOMP). Ceramide enhances oligomerization of pro-apoptotic Bcl-2 family proteins, ceramide channel, and reduces anti-apoptotic Bcl-2 proteins in the MOM. This process alters MOMP, resulting in generation of reactive oxygen species (ROS), cytochrome C release into the cytosol, caspase activation, and apoptosis. Ceramide regulates apoptosis through mitogen-activated protein kinases (MAPKs)-dependent and -independent pathways. Conversely, MAPKs alter ceramide generation by regulating the enzymes involving ceramide metabolism, affecting ceramide-induced apoptosis. Crosstalk between Bcl-2 family proteins, ROS, and many signaling pathways regulates ceramide-induced apoptosis. Growth factors rescue ceramide-induced apoptosis by regulating the enzymes involving ceramide metabolism, S1P, and signaling pathways including MAPKs. This article reviews evidence supporting a role of ceramide for apoptosis and discusses a role of mitochondria, including MOMP, Bcl-2 family proteins, ROS, and signaling pathways, and crosstalk between these factors in the regulation of ceramide-induced apoptosis of RTCs. A balancing role between ceramide and S1P and the strategy for preventing ceramide-induced apoptosis by growth factors are also discussed. PMID:25751724

  12. Cooperation of TOM and TIM23 complexes during translocation of proteins into mitochondria.

    Science.gov (United States)

    Waegemann, Karin; Popov-Čeleketić, Dušan; Neupert, Walter; Azem, Abdussalam; Mokranjac, Dejana

    2015-03-13

    Translocation of the majority of mitochondrial proteins from the cytosol into mitochondria requires the cooperation of TOM and TIM23 complexes in the outer and inner mitochondrial membranes. The molecular mechanisms underlying this cooperation remain largely unknown. Here, we present biochemical and genetic evidence that at least two contacts from the side of the TIM23 complex play an important role in TOM-TIM23 cooperation in vivo. Tim50, likely through its very C-terminal segment, interacts with Tom22. This interaction is stimulated by translocating proteins and is independent of any other TOM-TIM23 contact known so far. Furthermore, the exposure of Tim23 on the mitochondrial surface depends not only on its interaction with Tim50 but also on the dynamics of the TOM complex. Destabilization of the individual contacts reduces the efficiency of import of proteins into mitochondria and destabilization of both contacts simultaneously is not tolerated by yeast cells. We conclude that an intricate and coordinated network of protein-protein interactions involving primarily Tim50 and also Tim23 is required for efficient translocation of proteins across both mitochondrial membranes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Glucagon effects on the membrane potential and calcium uptake rate of rat liver mitochondria

    International Nuclear Information System (INIS)

    Wingrove, D.E.; Amatruda, J.M.; Gunter, T.E.

    1984-01-01

    It has been widely reported that the in vivo administration of glucagon to rats results in the stimulation of calcium influx in subsequently isolated liver mitochondria. The mechanism of this effect is investigated through simultaneous measurements of calcium uptake rate and mitochondrial membrane potential. This allows the measurement of the calcium uniporter conductance independent of hormonal effects on electron transport or respiration. Two experimental approaches are used. The first involves measuring the uptake of 40-50 nmol of Ca 2+ /mg of mitochondrial protein with the calcium dye antipyrylazo III; the second uses 45 Ca 2+ to follow uptake in the presence of 0.5 to 1.5 μM free calcium, buffered with HEDTA. In both cases a tetraphenyl phosphonium electrode is used to follow membrane potential, and membrane potential is varied using either malonate or butylmalonate in the presence of rotenone. The relative merits of these two approaches are discussed. The conductance of the calcium uniporter is found not to be stimulated by glucagon pretreatment. Also, the relative glucagon stimulation of both calcium influx and membrane potential is found to increase with increasing malonate concentration. These results imply that there is no direct stimulation of calcium uptake into liver mitochondria following glucagon treatment. The results are consistent with a glucagon stimulation of substrate transport, substrate oxidation, or a stimulation of electron transport resulting in an increased membrane potential and secondary stimulation of calcium uptake

  14. Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia.

    Directory of Open Access Journals (Sweden)

    Adrian B Hehl

    Full Text Available Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia is one of the earliest branching eukaryotes and harbors highly degenerated mitochondrial remnant organelles (mitosomes that lack a genome. Here we tested whether human Bax expressed in Giardia can be used to ablate mitosomes. We demonstrate that these organelles are neither targeted, nor compromised, by Bax. However, specialized compartments of the regulated secretory pathway are completely ablated by Bax. As a consequence, maturing cyst wall proteins that are sorted into these organelles are released into the cytoplasm, causing a developmental arrest and cell death. Interestingly, this ectopic cargo release is dependent on the carboxy-terminal 22 amino acids of Bax, and can be prevented by the Bax-inhibiting peptide Ku70. A C-terminally truncated Bax variant still localizes to secretory organelles, but is unable to permeabilize these membranes, uncoupling membrane targeting and cargo release. Even though mitosomes are too diverged to be recognized by Bax, off-target membrane permeabilization appears to be conserved and leads to cell death completely independently of mitochondria.

  15. Mitochondria can Power Cells to Life and Death

    Indian Academy of Sciences (India)

    molecular basis of pathogenicity and ... Mitochondria were discovered by R Altman in 1890 and the word was coined ... Diabetes mellitus ... 2 x 103 per cell) depending upon where and in which tissue they exist. They can .... is released, which then gears up other types of caspases to orchestrate .... Cellular Biology, CDFD.

  16. Rejuvenating cellular respiration for optimizing respiratory function: targeting mitochondria.

    Science.gov (United States)

    Agrawal, Anurag; Mabalirajan, Ulaganathan

    2016-01-15

    Altered bioenergetics with increased mitochondrial reactive oxygen species production and degradation of epithelial function are key aspects of pathogenesis in asthma and chronic obstructive pulmonary disease (COPD). This motif is not unique to obstructive airway disease, reported in related airway diseases such as bronchopulmonary dysplasia and parenchymal diseases such as pulmonary fibrosis. Similarly, mitochondrial dysfunction in vascular endothelium or skeletal muscles contributes to the development of pulmonary hypertension and systemic manifestations of lung disease. In experimental models of COPD or asthma, the use of mitochondria-targeted antioxidants, such as MitoQ, has substantially improved mitochondrial health and restored respiratory function. Modulation of noncoding RNA or protein regulators of mitochondrial biogenesis, dynamics, or degradation has been found to be effective in models of fibrosis, emphysema, asthma, and pulmonary hypertension. Transfer of healthy mitochondria to epithelial cells has been associated with remarkable therapeutic efficacy in models of acute lung injury and asthma. Together, these form a 3R model--repair, reprogramming, and replacement--for mitochondria-targeted therapies in lung disease. This review highlights the key role of mitochondrial function in lung health and disease, with a focus on asthma and COPD, and provides an overview of mitochondria-targeted strategies for rejuvenating cellular respiration and optimizing respiratory function in lung diseases. Copyright © 2016 the American Physiological Society.

  17. Mitochondria as Pharmacological Targets: The Discovery of Novel ...

    African Journals Online (AJOL)

    When food intake chronically exceeds the body's energy need, an efficient metabolism results in the storage of the excess energy as fat. Mitochondria are the main centre for energy production in eukaryotic cells. Mitochondrial proton cycling is responsible for a significant proportion of basal or standard metabolic rate, ...

  18. Mitochondria and aging: innocent bystanders or guilty parties?

    Science.gov (United States)

    Tońska, K; Sołyga, A; Bartnik, E

    2009-01-01

    There are many theories of aging and a number of them encompass the role of mitochondria in this process. Mitochondrial DNA mutations and deletions have been shown to accumulate in many tissues in mammals during aging. However, there is little evidence that these mutations could affect the functioning of aging tissues.

  19. 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.

  20. Mitochondria: An intriguing target for killing tumour-initiating cells

    Czech Academy of Sciences Publication Activity Database

    Yan, B.; Dong, L.; Neužil, Jiří

    2016-01-01

    Roč. 26, JAN 2016 (2016), s. 86-93 ISSN 1567-7249 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:86652036 Keywords : Tumour-initiating cells * ALPHA-TOCOPHERYL SUCCINATE * Therapeutic resistance * Mitochondria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.704, year: 2016

  1. Conserved genes encode guide RNAs in mitochondria of Crithidia fasciculata

    NARCIS (Netherlands)

    van der Spek, H.; Arts, G. J.; Zwaal, R. R.; van den Burg, J.; Sloof, P.; Benne, R.

    1991-01-01

    RNA editing is the post-transcriptional alteration of the nucleotide sequence of RNA, which in trypanosome mitochondria is characterized by the insertion and deletion of uridine residues. It has recently been proposed that the information for the sequence alteration in Leishmania tarentolae is

  2. Aprataxin localizes to mitochondria and preserves mitochondrial function

    DEFF Research Database (Denmark)

    Sykora, Peter; Croteau, Deborah L; Bohr, Vilhelm A

    2011-01-01

    aborted ligation reactions. We report herein that aprataxin localizes to mitochondria in human cells and we identify an N-terminal amino acid sequence that targets certain isoforms of the protein to this intracellular compartment. We also show that transcripts encoding this unique N-terminal stretch...

  3. Phosphorylation of formate dehydrogenase in potato tuber mitochondria

    DEFF Research Database (Denmark)

    Bykova, N.V.; Stensballe, A.; Egsgaard, H.

    2003-01-01

    Two highly phosphorylated proteins were detected after two-dimensional (blue native/SDS-PAGE) gel electrophoretic separation of the matrix fraction isolated from potato tuber mitochondria. These two phosphoproteins were identified by mass spectrometry as formate dehydrogenase (FDH) and the E1alpha...

  4. Mitochondria mediate septin cage assembly to promote autophagy of Shigella.

    Science.gov (United States)

    Sirianni, Andrea; Krokowski, Sina; Lobato-Márquez, Damián; Buranyi, Stephen; Pfanzelter, Julia; Galea, Dieter; Willis, Alexandra; Culley, Siân; Henriques, Ricardo; Larrouy-Maumus, Gerald; Hollinshead, Michael; Sancho-Shimizu, Vanessa; Way, Michael; Mostowy, Serge

    2016-07-01

    Septins, cytoskeletal proteins with well-characterised roles in cytokinesis, form cage-like structures around cytosolic Shigella flexneri and promote their targeting to autophagosomes. However, the processes underlying septin cage assembly, and whether they influence S. flexneri proliferation, remain to be established. Using single-cell analysis, we show that the septin cages inhibit S. flexneri proliferation. To study mechanisms of septin cage assembly, we used proteomics and found mitochondrial proteins associate with septins in S. flexneri-infected cells. Strikingly, mitochondria associated with S. flexneri promote septin assembly into cages that entrap bacteria for autophagy. We demonstrate that the cytosolic GTPase dynamin-related protein 1 (Drp1) interacts with septins to enhance mitochondrial fission. To avoid autophagy, actin-polymerising Shigella fragment mitochondria to escape from septin caging. Our results demonstrate a role for mitochondria in anti-Shigella autophagy and uncover a fundamental link between septin assembly and mitochondria. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  5. Lupeol induces S-phase arrest and mitochondria-mediated ...

    Indian Academy of Sciences (India)

    48

    Lupeol induces S-phase arrest and mitochondria-mediated apoptosis in cervical cancer cells. Nupoor Prasad1, Akash Sabarwal2, Umesh C. S. Yadav1, Rana P. Singh2,*. 1School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India. 2Cancer Biology Laboratory, School of Life Sciences, Jawaharlal ...

  6. Naturally Occurring Radioactive Materials (NORM)

    International Nuclear Information System (INIS)

    Gray, P.

    1997-01-01

    This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards they present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training)

  7. Naturally Occurring Radioactive Materials (NORM)

    Energy Technology Data Exchange (ETDEWEB)

    Gray, P. [ed.

    1997-02-01

    This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards they present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training).

  8. Ovarian ageing: the role of mitochondria in oocytes and follicles.

    Science.gov (United States)

    May-Panloup, Pascale; Boucret, Lisa; Chao de la Barca, Juan-Manuel; Desquiret-Dumas, Valérie; Ferré-L'Hotellier, Véronique; Morinière, Catherine; Descamps, Philippe; Procaccio, Vincent; Reynier, Pascal

    2016-11-01

    There is a great inter-individual variability of ovarian ageing, and almost 20% of patients consulting for infertility show signs of premature ovarian ageing. This feature, taken together with delayed childbearing in modern society, leads to the emergence of age-related ovarian dysfunction concomitantly with the desire for pregnancy. Assisted reproductive technology is frequently inefficacious in cases of ovarian ageing, thus raising the economic, medical and societal costs of the procedures. Ovarian ageing is characterized by quantitative and qualitative alteration of the ovarian oocyte reserve. Mitochondria play a central role in follicular atresia and could be the main target of the ooplasmic factors determining oocyte quality adversely affected by ageing. Indeed, the oocyte is the richest cell of the body in mitochondria and depends largely on these organelles to acquire competence for fertilization and early embryonic development. Moreover, the oocyte ensures the uniparental transmission and stability of the mitochondrial genome across the generations. This review focuses on the role played by mitochondria in ovarian ageing and on the possible consequences over the generations. PubMed was used to search the MEDLINE database for peer-reviewed original articles and reviews concerning mitochondria and ovarian ageing, in animal and human species. Searches were performed using keywords belonging to three groups: 'mitochondria' or 'mitochondrial DNA'; 'ovarian reserve', 'oocyte', 'ovary' or 'cumulus cells'; and 'ageing' or 'ovarian ageing'. These keywords were combined with other search phrases relevant to the topic. References from these articles were used to obtain additional articles. There is a close relationship, in mammalian models and humans, between mitochondria and the decline of oocyte quality with ageing. Qualitatively, ageing-related mitochondrial (mt) DNA instability, which leads to the accumulation of mtDNA mutations in the oocyte, plays a key role in

  9. Naturally occurring radionuclides in food

    International Nuclear Information System (INIS)

    Djujic, I.

    1995-01-01

    The naturally occurring radionuclides are the major source of radiation exposure to humans. The principal way of natural radiation exposure is the inhalation of 222 Rn decay products (about 85% of the total). The remainder is equally divided between internally deposited radionuclides, cosmic and terrestrial sources. In the present study, the content of 40 K, 210 Pb, 226 Ra, 230 Th, 232 Th and 238 U in representative food samples (milk, pork, beef, potatoes, wheat and corn flour) and samples of different food items that do not represent entire national production but provide interesting additional data for approximative calculation of naturally occurring radionuclide intake is presented. Daily weight of food eaten, participation of food groups, as well as daily intake by food of mentioned naturally occurring radionuclides in the Serbian diet was obtained on the base of house hold budget surveys. The result obtained for daily intake estimates in mBq for Serbian population are 78.1 ( 40 K), 38.2( 210 Pb), 52.3( 226 Ra), 2.0( 230 Th) and 12.5( 238 U). (author)

  10. 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.

  11. Early occurring and continuing effects

    International Nuclear Information System (INIS)

    Scott, B.R.; Hahn, F.F.

    1985-01-01

    This chapter deals with health-risk estimates for early and continuing effects of exposure to ionizing radiations that could be associated with light water nuclear power plants accidents. Early and continuing effects considered are nonneoplastic diseases and symptoms that normally occur soon after radiation exposure, but may also occur after years have passed. They are generally associated with relatively high (greater than 1 Gy) doses. For most of the effects considered, there is a practical dose threshold. Organs of primary interest, because of their high sensitivity or the likelihood of receiving a large radiation dose, are bone marrow, gastrointestinal tract, thyroid glands, lungs, skin, gonads, and eyes. In utero exposure of the fetus is also considered. New data and modeling techniques available since publication of the Reactor Safety Study (WASH 1400, 1975) were used along with data cited in the Study to develop improved health-risk models for morbidity and mortality. The new models are applicable to a broader range of accident scenarios, provide a more detailed treatment of dose protraction effects, and include morbidity effects not considered in the Reactor Safety Study. 115 references, 20 figures, 19 tables

  12. Naturally-occurring alpha activity

    Energy Technology Data Exchange (ETDEWEB)

    Mayneord, W V

    1960-12-01

    In view of the difficulties of assessing the significance of man-made radioactivity it is important to study for comparison the background of natural radioactivity against which the human race has evolved and lives. It is also important to define the present levels of activity so that it will be possible to detect and study as quickly as possible any changes which may occur owing to the release into the environment of new radioactive materials. Moreover, by the study of the behaviour of natural radioactivity light may be shed upon that of the artificially produced isotopes and a number of analogies traced between the two groups. These concepts have led to studies of naturally-occurring radioactive materials alongside a programme of research into fission products in food, water and air, as well as studies of the metabolism of both sets of materials in the human body. Since the last report there has been a useful increase in our knowledge of natural radioactivity in the biosphere, and its levels relative to the new man-made activities. These studies have necessitated technical developments, particularly in the methods of measuring and identifying alpha-ray emitters, to which group many of the more important natural radioactive materials belong.

  13. Dosis Facit Sanitatem—Concentration-Dependent Effects of Resveratrol on Mitochondria

    Directory of Open Access Journals (Sweden)

    Corina T. Madreiter-Sokolowski

    2017-10-01

    Full Text Available The naturally occurring polyphenol, resveratrol (RSV, is known for a broad range of actions. These include a positive impact on lifespan and health, but also pro-apoptotic anti-cancer properties. Interestingly, cell culture experiments have revealed a strong impact of RSV on mitochondrial function. The compound was demonstrated to affect mitochondrial respiration, structure and mass of mitochondria as well as mitochondrial membrane potential and, ultimately, mitochondria-associated cell death pathways. Notably, the mitochondrial effects of RSV show a very strict and remarkable concentration dependency: At low concentrations, RSV (<50 μM fosters cellular antioxidant defense mechanisms, activates AMP-activated protein kinase (AMPK- and sirtuin 1 (SIRT1-linked pathways and enhances mitochondrial network formation. These mechanisms crucially contribute to the cytoprotective effects of RSV against toxins and disease-related damage, in vitro and in vivo. However, at higher concentrations, RSV (>50 μM triggers changes in (sub-cellular Ca2+ homeostasis, disruption of mitochondrial membrane potential and activation of caspases selectively yielding apoptotic cancer cell death, in vitro and in vivo. In this review, we discuss the promising therapeutic potential of RSV, which is most probably related to the compound’s concentration-dependent manipulation of mitochondrial function and structure.

  14. Arsenic induces apoptosis in mouse liver is mitochondria dependent and is abrogated by N-acetylcysteine

    International Nuclear Information System (INIS)

    Santra, Amal; Chowdhury, Abhijit; Ghatak, Subhadip; Biswas, Ayan; Dhali, Gopal Krishna

    2007-01-01

    Arsenicosis, caused by arsenic contamination of drinking water supplies, is a major public health problem in India and Bangladesh. Chronic liver disease, often with portal hypertension occurs in chronic arsenicosis, contributes to the morbidity and mortality. The early cellular events that initiate liver cell injury due to arsenicosis have not been studied. Our aim was to identify the possible mechanisms related to arsenic-induced liver injury in mice. Liver injury was induced in mice by arsenic treatment. The liver was used for mitochondrial oxidative stress, mitochondrial permeability transition (MPT). Evidence of apoptosis was sought by TUNEL test, caspase assay and histology. Pretreatment with N-acetyl-L-cysteine (NAC) was done to modulate hepatic GSH level. Arsenic treatment in mice caused liver injury associated with increased oxidative stress in liver mitochondria and alteration of MPT. Altered MPT facilitated cytochrome c release in the cytosol, activation of caspase 9 and caspase 3 activities and apoptotic cell death. Pretreatment of NAC to arsenic-treated mice abrogated all these alteration suggesting a glutathione (GSH)-dependent mechanism. Oxidative stress in mitochondria and inappropriate MPT are important in the pathogenesis of arsenic induced apoptotic liver cell injury. The phenomenon is GSH dependent and supplementation of NAC might have beneficial effects

  15. Dissecting the integrative antioxidant and redox systems in plant mitochondria. Effect of stress and S-nitrosylation.

    Directory of Open Access Journals (Sweden)

    Juan José Lázaro

    2013-11-01

    Full Text Available Mitochondrial respiration provides the energy needed to drive metabolic and transport processes in cells. Mitochondria are a significant site of reactive oxygen species (ROS production in plant cells, and redox-system components obey fine regulation mechanisms that are essential in protecting the mitochondrial integrity. In addition to ROS, there are compelling indications that nitric oxide (NO. can be generated in this organelle by both reductive and oxidative pathways. ROS and reactive nitrogen species (RNS play a key role in signaling but they can also be deleterious via oxidation of macromolecules. The high production of ROS obligates mitochondria to be provided with a set of ROS scavenging mechanisms. The first line of mitochondrial antioxidants is composed of superoxide dismutase and the enzymes of the ascorbate-glutathione cycle, which are not only able to scavenge ROS but also to repair cell damage and possibly serve as redox sensors. The dithiol-disulfide exchanges form independent signaling nodes and act as antioxidant defense mechanisms as well as sensor proteins modulating redox signaling during development and stress adaptation. The presence of thioredoxin (Trx, peroxiredoxin (Prx and sulfiredoxin (Srx in the mitochondria has been recently reported. Cumulative results obtained from studies in salt stress models have demonstrated that these redox proteins play a significant role in the establishment of salt tolerance. The Trx/Prx/Srx system may be subjected to a fine regulated mechanism involving post-translational modifications, among which S-glutathionylation and S-nitrosylation seem to exhibit a critical role that is just beginning to be understood. This review summarizes our current knowledge in antioxidative systems in plant mitochondria, their interrelationships, mechanisms of compensation and some unresolved questions, with special focus on their response to abiotic stress.

  16. Evidence for loss of mitochondria in Microsporidia from a mitochondrial-type HSP70 in Nosema locustae.

    Science.gov (United States)

    Germot, A; Philippe, H; Le Guyader, H

    1997-08-01

    In molecular phylogenies based on ribosomal RNA, three amitochondriate protist lineages, Microsporidia, Metamonada (including diplomonads) and Parabasala (including trichomonads), are the earliest offshoots of the eukaryotic tree. As an explantation for the lack of mitochondria in these organisms, the hypothesis that they have diverged before the mitochondrial endosymbiosis is preferred to the less parsimonious hypothesis of several independent losses of the organelle. Nevertheless, if they had descended from mitochondrion-containing ancestors, it may be possible to find in their nuclear DNA genes that derive from the endosymbiont which gave rise to mitochondria. Based on similar evidence, secondary losses of mitochondria have recently been suggested for Entamoeba histolytica and for Trichomonas vaginalis. In this study, we have isolated a gene encoding a chaperone protein (HSP70, 70 kDa heat shock protein) from the microspordian Nosema locustae. In phylogenetic trees, this HSP70 was located within a group of sequences that in other lineages is targetted to the mitochondrial compartment, itself included in the proteobacterial clade. In addition, the N. locustae protein contained the GDAW(V) motif shared by mitochondrial and proteobacterial sequences, with only one conservative substitution. Moreover, microsporidia, a phylum which was assumed to emerge close to the base of the eukaryotic tree, appears as the sister-group of fungi in the HSP70 phylogeny, in agreement with some ultrastructural characters and phylogenies based on alpha- and beta-tubulins. Loss of mitochondria, now demonstrated for several amitochondriate groups, indicates that the common ancestor of all the extant eukaryotic species could have been a mitochondriate eukaryote.

  17. Naturally occurring methyl salicylate glycosides.

    Science.gov (United States)

    Mao, Ping; Liu, Zizhen; Xie, Meng; Jiang, Rui; Liu, Weirui; Wang, Xiaohong; Meng, Shen; She, Gaimei

    2014-01-01

    As an important part of non steroids anti-inflammation drug (NSAIDs), salicylate has developed from natural substance salicylic acid to natrium salicylicum, to aspirin. Now, methyl salicylate glycoside, a new derivative of salicylic acid, is modified with a -COOH group integrated one methyl radical into formic ether, and a -OH linked with a monosaccharide, a disaccharide or a trisaccharide unit by glycosidic linkage. It has the similar pharmacological activities, anti-inflammatory, analgesic, antipyretic and antithrombotic as the previous salicylates' without resulting in serious side effects, particularly the gastrointestinal toxicity. Owing to the superiority of those significant bioactivities, methyl salicylate glycosides have became a hot research area in NSAIDs for several years. This paper compiles all 9 naturally occurring methyl salicylate glycosides, their distribution of the resource and pharmacological mechanism, which could contribute to the new drug discovery.

  18. Mitochondria, Energetics, Epigenetics, and Cellular Responses to Stress

    Science.gov (United States)

    McAllister, Kimberly; Worth, Leroy; Haugen, Astrid C.; Meyer, Joel N.; Domann, Frederick E.; Van Houten, Bennett; Mostoslavsky, Raul; Bultman, Scott J.; Baccarelli, Andrea A.; Begley, Thomas J.; Sobol, Robert W.; Hirschey, Matthew D.; Ideker, Trey; Santos, Janine H.; Copeland, William C.; Tice, Raymond R.; Balshaw, David M.; Tyson, Frederick L.

    2014-01-01

    Background: Cells respond to environmental stressors through several key pathways, including response to reactive oxygen species (ROS), nutrient and ATP sensing, DNA damage response (DDR), and epigenetic alterations. Mitochondria play a central role in these pathways not only through energetics and ATP production but also through metabolites generated in the tricarboxylic acid cycle, as well as mitochondria–nuclear signaling related to mitochondria morphology, biogenesis, fission/fusion, mitophagy, apoptosis, and epigenetic regulation. Objectives: We investigated the concept of bidirectional interactions between mitochondria and cellular pathways in response to environmental stress with a focus on epigenetic regulation, and we examined DNA repair and DDR pathways as examples of biological processes that respond to exogenous insults through changes in homeostasis and altered mitochondrial function. Methods: The National Institute of Environmental Health Sciences sponsored the Workshop on Mitochondria, Energetics, Epigenetics, Environment, and DNA Damage Response on 25–26 March 2013. Here, we summarize key points and ideas emerging from this meeting. Discussion: A more comprehensive understanding of signaling mechanisms (cross-talk) between the mitochondria and nucleus is central to elucidating the integration of mitochondrial functions with other cellular response pathways in modulating the effects of environmental agents. Recent studies have highlighted the importance of mitochondrial functions in epigenetic regulation and DDR with environmental stress. Development and application of novel technologies, enhanced experimental models, and a systems-type research approach will help to discern how environmentally induced mitochondrial dysfunction affects key mechanistic pathways. Conclusions: Understanding mitochondria–cell signaling will provide insight into individual responses to environmental hazards, improving prediction of hazard and susceptibility to

  19. Bcl-xL-mediated remodeling of rod and cone synaptic mitochondria after postnatal lead exposure: electron microscopy, tomography and oxygen consumption.

    Science.gov (United States)

    Perkins, Guy A; Scott, Ray; Perez, Alex; Ellisman, Mark H; Johnson, Jerry E; Fox, Donald A

    2012-01-01

    and dark-adapted photoreceptor synaptic terminal QO(2). Bcl-xL partially blocked many of the lead-induced alterations relative to controls. However, spherules still had partially decreased abundance, whereas pedicles still had increased branching, increased crista segments per volume, and increased crista junction diameter. Moreover, photoreceptor and synaptic QO(2) were only partially recovered. These findings reveal cellular and compartmental specific differences in the structure and vulnerability of rod and cone inner segment and synaptic mitochondria to postnatal lead exposure. Spherule and pedicle mitochondria in lead-exposed mice displayed complex and distinguishing patterns of cristae and matrix damage and remodeling consistent with studies showing that synaptic mitochondria are more sensitive to Ca(2+) overload, oxidative stress, and ATP loss than non-synaptic mitochondria. The lead-induced decreases in QO(2) likely resulted from the decreased spherule cristae abundance and smaller cristae, perhaps due to Bax-mediated effects as they occurred in apoptotic rod inner segments. The increase in pedicle cristae abundance and CJ diameter could have resulted from increased Drp1-mediated fission, as small mitochondrial fragments were observed. The mechanisms of Bcl-xL-mediated remodeling might occur via interaction with formation of CJ protein 1 (Fcj1), whereas the partial protection of synaptic QO(2) might result from the enhanced efficiency of energy metabolism via Bcl-xL's direct interaction with the F1F0 ATP synthase and/or regulation of cellular redox status. These lead-induced alterations in photoreceptor synaptic terminal mitochondria likely underlie the persistent scotopic and mesopic deficits in lead-exposed children, workers, and experimental animals. Our findings stress the clinical and scientific importance of examining synaptic dysfunction following injury or disease during development, and developing therapeutic treatments that prevent synaptic

  20. What occurred in the reactors

    International Nuclear Information System (INIS)

    Kudo, Kazuhiko

    2013-01-01

    Described is what occurred in the reactors of Fukushima Daiichi Nuclear Power Plant at the Tohoku earthquake and tsunami (Mar. 11, 2011) from the aspect of engineering science. The tsunami attacked the Plant 1 hr after the quake. The Plant had reactors in buildings no.1-4 at 10 m height from the normal sea level which was flooded by 1.5-5.5 m high wave. All reactors in no.1-6 in the Plant were the boiling water type, and their core nuclear reactions were stopped within 3 sec due to the first quake by control rods inserted automatically. Reactors in no.1-5 lost their external AC power sources by the breakdown and subsequent submergence (no.1-4) of various equipments and in no.1, 2 and 4, the secondary DC power was then lost by the battery death. Although the isolation condenser started to cool the reactor in no.1 after DC cut, its valve was then kept closed to heat up the reactor, leading to the reaction of heated Zr in the fuel tube and water to yield H 2 which was accumulated in the building: the cause of hydrogen explosion on 12th. The reactor in no.2 had the reactor core isolation cooling system (RCIC) which operated normally for few hrs, then probably stopped to heat up the reactor, resulting in meltdown of the core but no explosion occurred because of the opened door of the blowout panel on the wall by the blast of no.1 explosion. The reactor in no.3 had RCIC and high pressure coolant injection system, but their works stopped to result in the core damage and H 2 accumulation leading to the explosion on 14th. The reactor in no.4 had not been operated because of its periodical annual examination, but was explored on 15th, of which cause was thought to be due to backward flow of H 2 from no.3. Finally, the author discusses about this accident from the industrial aspect of the design of safety level (defense in depth) on international views, and problems and tasks given. (T.T.)

  1. Earl occurring and continuing effects

    International Nuclear Information System (INIS)

    Scott, B.R.; Hahn, F.F.

    1989-01-01

    This chapter develops health-risk models for early and continuing effects of exposure to beta or gamma radiation that could be associated with light water nuclear power plant accidents. The main purpose of the chapter is to provide details on each health-risk model and on the data used. Early and continuing effects considered are prodromal symptoms and nonneoplastic diseases that usually occur soon after a brief radiation exposure. These effects are generally associated with relatively high (greater than 1 Gy) absorbed organ doses. For most of the effects considered, there is an absorbed organ dose threshold below which no effects are seen. Some information is provided on health effects observed in victims of the Chernobyl power plant accident. Organs of primary interest, because of their high sensitivity or their potential for receiving large doses, are bone marrow, gastrointestinal tract, thyroid glands, lungs, skin, gonads, and eyes. Exposure of the fetus is also considered. Additional data and modeling techniques available since publication of the Reactor Safety Study were used to obtain models for morbidity and mortality

  2. Does overtraining occur in triathletes?

    Directory of Open Access Journals (Sweden)

    I Margaritis

    2003-06-01

    Full Text Available 1. Objective: Long distance triathlon training is characterized by considerably high volume training loads. This volume can provoke an overtraining state. The aim of the study was to determine whether overtraining occurs in well-trained male triathletes in relation with their volume training loads. 2. Experimental design: A questionnaire investigation was completed two days before the Nice long-distance triathlon (October 1995: 4-km swim, 120-km bike ride and 30-km run. 3. Participants: Ninety-three well-trained male triathletes who took part in the triathlon race. 4. Measures: A questionnaire to relate clinical symptoms, which are known to appear in case of overtraining, was collected. 5. Results: 39.8% of the questioned triathletes reported a decrease in triathlon performances within the last month preceding the race. Moreover, these triathletes exhibited significantly more overtraining-relied symptoms than the others (5.9±3.8 vs 3.4±2.6, P<0.05. Surprisingly, the occurrence of overtraining in triathletes appears not to depend on the volume training loads. 6. Conclusions: These results suggest that overtraining has to be considered in the case of triathletes. This preliminary study evidences the need for further investigation in order to monitor triathletes training respond and prevent overtraining.

  3. [Acetylcholine activation of alpha-ketoglutarate oxidation in liver mitochondria].

    Science.gov (United States)

    Shostakovskaia, I V; Doliba, N M; Gordiĭ, S K; Babskiĭ, A M; Kondrashova, M N

    1986-01-01

    Activation of alpha-ketoglutarate oxidation in the rat liver mitochondria takes place 15 and 30 min after intraperitoneal injection of acetyl choline. This mediator in doses of 25, 50 and 100 micrograms per 100 g of body weight causes a pronounced stimulation of phosphorylation respiration rate and calcium capacity of mitochondria with alpha-ketoglutarate oxidation. Acetyl choline is found to have a moderate inhibitory action on oxidation of lower (physiological) concentrations of succinate. Its stimulating action on alpha-ketoglutarate oxidation is associated with activation of M-cholinoreceptors; atropine, a choline-blocker, removes completely this effect. It is supposed that alpha-ketoglutarate and succinate are included into the composition of two reciprocal hormonal-substrate nucleotide systems.

  4. Membrane potential of mitochondria from the liver of irradiated rats

    International Nuclear Information System (INIS)

    Fomenko, B.S.; Kaminin, A.N.; Elfimova, I.A.; Akoev, I.G.

    1977-01-01

    Measurements of the membrane potential of rat liver mitochondria 1 hour after irradiation with 800 R dose showed a decrease of its value. The potential decreased against the background of the activation of the generating mechanisms (the electron transport chain and ATP-ases). During energization of the membranes by the electron transport chain similar effect has been observed with different oxidation substrates (NAD linked substrates and succinate). It suggests that similar causative factors are at the basis of the changes observed. It is quite possible that the increase in the rate of both mitochondria respiration and ATP hydrolysis after the irradiation of animals was a consequence of the radiation-induced decrease in the potential value. (author)

  5. Mitochondria, Energy and Cancer: The Relationship with Ascorbic Acid

    Science.gov (United States)

    González, Michael J.; Rosario-Pérez, Glorivee; Guzmán, Angélica M.; Miranda-Massari, Jorge R.; Duconge, Jorge; Lavergne, Julio; Fernandez, Nadia; Ortiz, Norma; Quintero, Ana; Mikirova, Nina; Riordan, Neil H.; Ricart, Carlos M.

    2012-01-01

    Ascorbic Acid (AA) has been used in the prevention and treatment of cancer with reported effectiveness. Mitochondria may be one of the principal targets of ascorbate's cellular activity and it may play an important role in the development and progression of cancer. Mitochondria, besides generating adenosine triphosphate (ATP), has a role in apoptosis regulation and in the production of regulatory oxidative species that may be relevant in gene expression. At higher concentrations AA may increase ATP production by increasing mitochondrial electron flux, also may induce apoptotic cell death in tumor cell lines, probably via its pro-oxidant action In contrast, at lower concentrations AA displays antioxidant properties that may prevent the activation of oxidant-induced apoptosis. These concentration dependent activities of ascorbate may explain in part the seemingly contradictory results that have been reported previously. PMID:23565030

  6. The role of mitochondria in yeast programmed cell death

    International Nuclear Information System (INIS)

    Guaragnella, Nicoletta; Ždralević, Maša; Antonacci, Lucia; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

    2012-01-01

    Mammalian apoptosis and yeast programmed cell death (PCD) share a variety of features including reactive oxygen species production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid-induced PCD (AA-PCD) which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.

  7. The dynamic regulation of NAD metabolism in mitochondria

    Science.gov (United States)

    Stein, Liana Roberts; Imai, Shin-ichiro

    2012-01-01

    Mitochondria are intracellular powerhouses that produce ATP and carry out diverse functions for cellular energy metabolism. While the maintenance of an optimal NAD/NADH ratio is essential for mitochondrial function, it has recently become apparent that the maintenance of the mitochondrial NAD pool also has critical importance. The biosynthesis, transport, and catabolism of NAD and its key intermediates play an important role in the regulation of NAD-consuming mediators, such as sirtuins, poly-ADP-ribose polymerases, and CD38/157 ectoenzymes, in intra- and extracellular compartments. Mitochondrial NAD biosynthesis is also modulated in response to nutritional and environmental stimuli. In this article, we discuss this dynamic regulation of NAD metabolism in mitochondria to shed light on the intimate connection between NAD and mitochondrial function. PMID:22819213

  8. 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

  9. A cAMP/PKA/Kinesin-1 Axis Promotes the Axonal Transport of Mitochondria in Aging Drosophila Neurons.

    Science.gov (United States)

    Vagnoni, Alessio; Bullock, Simon L

    2018-04-23

    Mitochondria play fundamental roles within cells, including energy provision, calcium homeostasis, and the regulation of apoptosis. The transport of mitochondria by microtubule-based motors is critical for neuronal structure and function. This process allows local requirements for mitochondrial functions to be met and also facilitates recycling of these organelles [1, 2]. An age-related reduction in mitochondrial transport has been observed in neurons of mammalian and non-mammalian organisms [3-6], and has been proposed to contribute to the broader decline in neuronal function that occurs during aging [3, 5-7]. However, the factors that influence mitochondrial transport in aging neurons are poorly understood. Here we provide evidence using the tractable Drosophila wing nerve system that the cyclic AMP/protein kinase A (cAMP/PKA) pathway promotes the axonal transport of mitochondria in adult neurons. The level of the catalytic subunit of PKA decreases during aging, and acute activation of the cAMP/PKA pathway in aged flies strongly stimulates mitochondrial motility. Thus, the age-related impairment of transport is reversible. The expression of many genes is increased by PKA activation in aged flies. However, our results indicate that elevated mitochondrial transport is due in part to upregulation of the heavy chain of the kinesin-1 motor, the level of which declines during aging. Our study identifies evolutionarily conserved factors that can strongly influence mitochondrial motility in aging neurons. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  10. The oncolytic peptide LTX-315 induces cell death and DAMP release by mitochondria distortion in human melanoma cells

    Science.gov (United States)

    Eike, Liv-Marie; Yang, Nannan; Rekdal, Øystein; Sveinbjørnsson, Baldur

    2015-01-01

    Host defense peptides (HDPs) are naturally occurring molecules found in most species, in which they play a significant role in the first line defense against intruding pathogens, and several HDPs have been shown to possess anticancer activity. Structure-activity relationship studies on the HDP bovine lactoferricin revealed a de novo design of a nonamer peptide LTX-315, with oncolytic properties. In the present study, we investigated the oncolytic activity of LTX-315 in human melanoma cells (A375). LTX-315 induced a rapid plasma membrane disruption and cell death within 2 hours. At a low concentration, fluorescence-labeled LTX-315 was internalized and accumulated in cytoplasmic vacuoles in close proximity to the mitochondria. The mitochondrial membrane potential was shown to depolarize as a consequence of LTX-315 treatment and at ultrastructural level, the mitochondria morphology was significantly altered. Release of danger signals (DAMPs) such as ATP, Cytochrome C and HMGB1 into the cell supernatant of cultured cells was evident minutes after peptide treatment. The oncolytic effect of LTX-315 involving perturbation of both the cell membrane and the mitochondria with subsequent release of DAMPs may highlight the ability of LTX-315 to induce complete regression and long-term protective immune responses as previously reported in experimental animal models. PMID:26472184

  11. Genetic diversity, molecular phylogeny and selection evidence of the silkworm mitochondria implicated by complete resequencing of 41 genomes

    Directory of Open Access Journals (Sweden)

    Tellier Laurent C

    2010-03-01

    Full Text Available Abstract Background Mitochondria are a valuable resource for studying the evolutionary process and deducing phylogeny. A few mitochondria genomes have been sequenced, but a comprehensive picture of the domestication event for silkworm mitochondria remains to be established. In this study, we integrate the extant data, and perform a whole genome resequencing of Japanese wild silkworm to obtain breakthrough results in silkworm mitochondrial (mt population, and finally use these to deduce a more comprehensive phylogeny of the Bombycidae. Results We identified 347 single nucleotide polymorphisms (SNPs in the mt genome, but found no past recombination event to have occurred in the silkworm progenitor. A phylogeny inferred from these whole genome SNPs resulted in a well-classified tree, confirming that the domesticated silkworm, Bombyx mori, most recently diverged from the Chinese wild silkworm, rather than from the Japanese wild silkworm. We showed that the population sizes of the domesticated and Chinese wild silkworms both experience neither expansion nor contraction. We also discovered that one mt gene, named cytochrome b, shows a strong signal of positive selection in the domesticated clade. This gene is related to energy metabolism, and may have played an important role during silkworm domestication. Conclusions We present a comparative analysis on 41 mt genomes of B. mori and B. mandarina from China and Japan. With these, we obtain a much clearer picture of the evolution history of the silkworm. The data and analyses presented here aid our understanding of the silkworm in general, and provide a crucial insight into silkworm phylogeny.

  12. Fructose-Drinking Water Induced Nonalcoholic Fatty Liver Disease and Ultrastructural Alteration of Hepatocyte Mitochondria in Male Wistar Rat

    Directory of Open Access Journals (Sweden)

    Norshalizah Mamikutty

    2015-01-01

    Full Text Available Background. Nonalcoholic fatty liver disease (NAFLD is one of the complications of the metabolic syndrome. It encompasses a wide range of disease spectrum from simple steatosis to liver cirrhosis. Structural alteration of hepatic mitochondria might be involved in the pathogenesis of NAFLD. Aims. In the present study, we used a newly established model of fructose-induced metabolic syndrome in male Wistar rats in order to investigate the ultrastructural changes in hepatic mitochondria that occur with fructose consumption and their association with NAFLD pathogenesis. Methods. The concentration of fructose-drinking water (FDW used in this study was 20%. Six male Wistar rats were supplemented with FDW 20% for eight weeks. Body composition and metabolic parameters were measured before and after 8 weeks of FDW 20%. Histomorphology of the liver was evaluated and ultrastructural changes of mitochondria were assessed with transmission electron micrograph. Results. After 8 weeks of fructose consumption, the animals developed several features of the metabolic syndrome. Moreover, fructose consumption led to the development of macrovesicular hepatic steatosis and mitochondrial ultrastructural changes, such as increase in mitochondrial size, disruption of the cristae, and reduction of matrix density. Conclusion. We conclude that in male Wistar rat 8-week consumption of FDW 20% leads to NAFLD likely via mitochondrial structural alteration.

  13. The rapid mode of calcium uptake into heart mitochondria (RaM): comparison to RaM in liver mitochondria.

    Science.gov (United States)

    Buntinas, L; Gunter, K K; Sparagna, G C; Gunter, T E

    2001-04-02

    A mechanism of Ca(2+) uptake, capable of sequestering significant amounts of Ca(2+) from cytosolic Ca(2+) pulses, has previously been identified in liver mitochondria. This mechanism, the Rapid Mode of Ca(2+) uptake (RaM), was shown to sequester Ca(2+) very rapidly at the beginning of each pulse in a sequence [Sparagna et al. (1995) J. Biol. Chem. 270, 27510-27515]. The existence and properties of RaM in heart mitochondria, however, are unknown and are the basis for this study. We show that RaM functions in heart mitochondria with some of the characteristics of RaM in liver, but its activation and inhibition are quite different. It is feasible that these differences represent different physiological adaptations in these two tissues. In both tissues, RaM is highly conductive at the beginning of a Ca(2+) pulse, but is inhibited by the rising [Ca(2+)] of the pulse itself. In heart mitochondria, the time required at low [Ca(2+)] to reestablish high Ca(2+) conductivity via RaM i.e. the 'resetting time' of RaM is much longer than in liver. RaM in liver mitochondria is strongly activated by spermine, activated by ATP or GTP and unaffected by ADP and AMP. In heart, RaM is activated much less strongly by spermine and unaffected by ATP or GTP. RaM in heart is strongly inhibited by AMP and has a biphasic response to ADP; it is activated at low concentrations and inhibited at high concentrations. Finally, an hypothesis consistent with the data and characteristics of liver and heart is presented to explain how RaM may function to control the rate of oxidative phosphorylation in each tissue. Under this hypothesis, RaM functions to create a brief, high free Ca(2+) concentration inside mitochondria which may activate intramitochondrial metabolic reactions with relatively small amounts of Ca(2+) uptake. This hypothesis is consistent with the view that intramitochondrial [Ca(2+)] may be used to control the rate of ADP phosphorylation in such a way as to minimize the probability of

  14. Mitochondria as determinant of nucleotide pools and chromosomal stability

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Munch-Petersen, Birgitte; Stevnsner, Tinna

    2007-01-01

    Mitochondrial function plays an important role in multiple human diseases and mutations in the mitochondrial genome have been detected in nearly every type of cancer investigated to date. However, the mechanism underlying the interrelation is unknown. We used human cell lines depleted of mitochon...... mitochondrial activity. Our results suggest that mitochondria are central players in maintaining genomic stability and in controlling essential nuclear processes such as upholding a balanced supply of nucleotides....

  15. Functional Mitochondria Are Important for the Effect of Resveratrol

    DEFF Research Database (Denmark)

    Widlund, Anne Lykkegaard; Baral, Kaushal; Dalgaard, Louise Torp

    2017-01-01

    Resveratrol (Resv) is a polyphenol reported to modulate mitochondrial activity. The aim was to use HeLa and 143B cells to characterize the action of Resv on mitochondrial activity, cell size and proliferation using wild type (WT) and Rho 0 cells deficient in mitochondrial DNA. In both HeLa WT and......, but not in Rho 0 when treated with Resv. Overall, the findings presented indicate that functional mitochondria are a prerequisite for cell enlargement by Resv....

  16. Mitochondria: An Organelle of Bacterial Origin Controlling Inflammation

    Directory of Open Access Journals (Sweden)

    Alain Meyer

    2018-04-01

    Full Text Available Inflammation is a cellular and molecular response to infection and/or tissues injury. While a suited inflammatory response in intensity and time allows for killing pathogens, clearing necrotic tissue, and healing injury; an excessive inflammatory response drives various diseases in which inflammation and tissues damages/stress self-sustain each other. Microbes have been poorly implied in non-resolving inflammation, emphasizing the importance of endogenous regulation of inflammation. Mitochondria have been historically identified as the main source of cellular energy, by coupling the oxidation of fatty acids and pyruvate with the production of high amount of adenosine triphosphate by the electron transport chain. Mitochondria are also the main source of reactive oxygen species. Interestingly, research in the last decade has highlighted that since its integration in eukaryote cells, this organelle of bacterial origin has not only been tolerated by immunity, but has also been placed as a central regulator of cell defense. In intact cells, mitochondria regulate cell responses to critical innate immune receptors engagement. Downstream intracellular signaling pathways interact with mitochondrial proteins and are tuned by mitochondrial functioning. Moreover, upon cell stress or damages, mitochondrial components are released into the cytoplasm or the extra cellular milieu, where they act as danger signals when recognized by innate immune receptors. Finally, by regulating the energetic state of immunological synapse between dendritic cells and lymphocytes, mitochondria regulate the inflammation fate toward immunotolerance or immunogenicity. As dysregulations of these processes have been recently involved in various diseases, the identification of the underlying mechanisms might open new avenues to modulate inflammation.

  17. Modeling population dynamics of mitochondria in mammalian cells

    Science.gov (United States)

    Kornick, Kellianne; Das, Moumita

    Mitochondria are organelles located inside eukaryotic cells and are essential for several key cellular processes such as energy (ATP) production, cell signaling, differentiation, and apoptosis. All organisms are believed to have low levels of variation in mitochondrial DNA (mtDNA), and alterations in mtDNA are connected to a range of human health conditions, including epilepsy, heart failure, Parkinsons disease, diabetes, and multiple sclerosis. Therefore, understanding how changes in mtDNA accumulate over time and are correlated to changes in mitochondrial function and cell properties can have a profound impact on our understanding of cell physiology and the origins of some diseases. Motivated by this, we develop and study a mathematical model to determine which cellular parameters have the largest impact on mtDNA population dynamics. The model consists of coupled ODEs to describe subpopulations of healthy and dysfunctional mitochondria subject to mitochondrial fission, fusion, autophagy, and mutation. We study the time evolution and stability of each sub-population under specific selection biases and pressures by tuning specific terms in our model. Our results may provide insights into how sub-populations of mitochondria survive and evolve under different selection pressures. This work was supported by a Grant from the Moore Foundation.

  18. Molecular Strategies for Targeting Antioxidants to Mitochondria: Therapeutic Implications

    Science.gov (United States)

    2015-01-01

    Abstract Mitochondrial function and specifically its implication in cellular redox/oxidative balance is fundamental in controlling the life and death of cells, and has been implicated in a wide range of human pathologies. In this context, mitochondrial therapeutics, particularly those involving mitochondria-targeted antioxidants, have attracted increasing interest as potentially effective therapies for several human diseases. For the past 10 years, great progress has been made in the development and functional testing of molecules that specifically target mitochondria, and there has been special focus on compounds with antioxidant properties. In this review, we will discuss several such strategies, including molecules conjugated with lipophilic cations (e.g., triphenylphosphonium) or rhodamine, conjugates of plant alkaloids, amino-acid- and peptide-based compounds, and liposomes. This area has several major challenges that need to be confronted. Apart from antioxidants and other redox active molecules, current research aims at developing compounds that are capable of modulating other mitochondria-controlled processes, such as apoptosis and autophagy. Multiple chemically different molecular strategies have been developed as delivery tools that offer broad opportunities for mitochondrial manipulation. Additional studies, and particularly in vivo approaches under physiologically relevant conditions, are necessary to confirm the clinical usefulness of these molecules. Antioxid. Redox Signal. 22, 686–729. PMID:25546574

  19. Viral degradasome hijacks mitochondria to suppress innate immunity

    Science.gov (United States)

    Goswami, Ramansu; Majumdar, Tanmay; Dhar, Jayeeta; Chattopadhyay, Saurabh; Bandyopadhyay, Sudip K; Verbovetskaya, Valentina; Sen, Ganes C; Barik, Sailen

    2013-01-01

    The balance between the innate immunity of the host and the ability of a pathogen to evade it strongly influences pathogenesis and virulence. The two nonstructural (NS) proteins, NS1 and NS2, of respiratory syncytial virus (RSV) are critically required for RSV virulence. Together, they strongly suppress the type I interferon (IFN)-mediated innate immunity of the host cells by degrading or inhibiting multiple cellular factors required for either IFN induction or response pathways, including RIG-I, IRF3, IRF7, TBK1 and STAT2. Here, we provide evidence for the existence of a large and heterogeneous degradative complex assembled by the NS proteins, which we named “NS-degradasome” (NSD). The NSD is roughly ∼300-750 kD in size, and its degradative activity was enhanced by the addition of purified mitochondria in vitro. Inside the cell, the majority of the NS proteins and the substrates of the NSD translocated to the mitochondria upon RSV infection. Genetic and pharmacological evidence shows that optimal suppression of innate immunity requires mitochondrial MAVS and mitochondrial motility. Together, we propose a novel paradigm in which the mitochondria, known to be important for the innate immune activation of the host, are also important for viral suppression of the innate immunity. PMID:23877405

  20. Identification of nitric oxide in mitochondria of myometrium cell

    Directory of Open Access Journals (Sweden)

    Danylovych Yu. V.

    2015-06-01

    Full Text Available Aim. To demonstrate the possibility of NO synthesis in intact myocytes of uterus. Methods. Confocal scanning microscopy method, NO-sensitive fluorescent probe DAF-FM, MitoTracker Orange CM-H2TMRos. Results. The basal production of NO in intact myocytes was shown using DAF-FM. Incubation of myocytes with NO donor – sodium nitroprusside (SNP – led to an increase of the DAF-FM-T fluorescent signal. On the contrary, the addition of NO-synthase inhibitor – N-nitro-L-arginine (NA – results in the reduction of fluorescent intensity. It was demonstrated colocalizition of specific probe for mitochondria MitoTracker Orange CM-H2TMRos and NO-sensitive dye DAF-FM. Conclusions. For the first time it has been demonstrated the presence of NO in smooth muscle cell mitochondria using laser confocal microscopy, NO-sensitive probe DAF-FM and specific marker of the functionally active mitochondria MitoTracker Orange CM-H2TMRos.

  1. New Insights in the Amyloid-Beta Interaction with Mitochondria

    Directory of Open Access Journals (Sweden)

    Carlos Spuch

    2012-01-01

    Full Text Available Biochemical and morphological alterations of mitochondria may play an important role in the pathogenesis of Alzheimer’s disease (AD. Particularly, mitochondrial dysfunction is a hallmark of amyloid-beta-induced neuronal toxicity in Alzheimer’s disease. The recent emphasis on the intracellular biology of amyloid-beta and its precursor protein (APP has led researchers to consider the possibility that mitochondria-associated and mitochondrial amyloid-beta may directly cause neurotoxicity. Both proteins are known to localize to mitochondrial membranes, block the transport of nuclear-encoded mitochondrial proteins to mitochondria, interact with mitochondrial proteins, disrupt the electron transport chain, increase reactive oxygen species production, cause mitochondrial damage, and prevent neurons from functioning normally. In this paper, we will outline current knowledge of the intracellular localization of amyloid-beta. Moreover, we summarize evidence from AD postmortem brain as well as animal AD models showing that amyloid-beta triggers mitochondrial dysfunction through a number of pathways such as impairment of oxidative phosphorylation, elevation of reactive oxygen species production, alteration of mitochondrial dynamics, and interaction with mitochondrial proteins. Thus, this paper supports the Alzheimer cascade mitochondrial hypothesis such as the most important early events in this disease, and probably one of the future strategies on the therapy of this neurodegenerative disease.

  2. Developing CNS mitochondria oxidative phosphorylation P/O/ADP/O index for rats

    International Nuclear Information System (INIS)

    Egana, E.; Diaz, G.

    1975-01-01

    The effect of whole-body-gamma irradiation on developing CNS mitochondria oxidative phosphorylation was studied through the P/O/ADP/O index; three irradiation doses (5, 50 and 500 R) were employed at neonatal stage and both 'prompt' (10 min approx,) and 'delayed' (7 days for 500 R exposure, 21 days for 5 and 50 R) effects were observed. In the 'prompt' effects investigated after 500 R exposure, the oxidative phosphorylation diminished; the same occurred at 7 days with this dose ('delayed' effect). With doses of 5 and 50 R there was no alteration of oxidative phosphorylation as a 'prompt' effect, but it diminished at 21 days post irradiation. The uncoupling between respiration and oxidative phosphorylation should explain - at least, in part -these results. (author)

  3. Developing CNS mitochondria oxidative phosphorylation P/O/ADP/O index for rats

    Energy Technology Data Exchange (ETDEWEB)

    Egana, E; Diaz, G [Institute of Experimental Medicine, Santiago (Chile). Lab. of Neurochemistry

    1975-11-01

    The effect of whole-body-gamma irradiation on developing CNS mitochondria oxidative phosphorylation was studied through the P/O/ADP/O index; three irradiation doses (5, 50 and 500 R) were employed at neonatal stage and both 'prompt' (10 min approx,) and 'delayed' (7 days for 500 R exposure, 21 days for 5 and 50 R) effects were observed. In the 'prompt' effects investigated after 500 R exposure, the oxidative phosphorylation diminished; the same occurred at 7 days with this dose ('delayed' effect). With doses of 5 and 50 R there was no alteration of oxidative phosphorylation as a 'prompt' effect, but it diminished at 21 days post irradiation. The uncoupling between respiration and oxidative phosphorylation should explain - at least, in part -these results.

  4. The Injury and Therapy of Reactive Oxygen Species in Intracerebral Hemorrhage Looking at Mitochondria

    Directory of Open Access Journals (Sweden)

    Jie Qu

    2016-01-01

    Full Text Available Intracerebral hemorrhage is an emerging major health problem often resulting in death or disability. Reactive oxygen species (ROS have been identified as one of the major damaging factors in ischemic stroke. However, there is less discussion about ROS in hemorrhage stroke. Metabolic products of hemoglobin, excitatory amino acids, and inflammatory cells are all sources of ROS, and ROS harm the central nervous system through cell death and structural damage, especially disruption of the blood-brain barrier. We have considered the antioxidant system of the CNS itself and the drugs aiming to decrease ROS after ICH, and we find that mitochondria are key players in all of these aspects. Moreover, when the mitochondrial permeability transition pore opens, ROS-induced ROS release, which leads to extensive liberation of ROS and mitochondrial failure, occurs. Therefore, the mitochondrion may be a significant target for elucidating the problem of ROS in ICH; however, additional experimental support is required.

  5. Nipah virus entry can occur by macropinocytosis

    International Nuclear Information System (INIS)

    Pernet, Olivier; Pohl, Christine; Ainouze, Michelle; Kweder, Hasan; Buckland, Robin

    2009-01-01

    Nipah virus (NiV) is a zoonotic biosafety level 4 paramyxovirus that emerged recently in Asia with high mortality in man. NiV is a member, with Hendra virus (HeV), of the Henipavirus genus in the Paramyxoviridae family. Although NiV entry, like that of other paramyxoviruses, is believed to occur via pH-independent fusion with the host cell's plasma membrane we present evidence that entry can occur by an endocytic pathway. The NiV receptor ephrinB2 has receptor kinase activity and we find that ephrinB2's cytoplasmic domain is required for entry but is dispensable for post-entry viral spread. The mutation of a single tyrosine residue (Y304F) in ephrinB2's cytoplasmic tail abrogates NiV entry. Moreover, our results show that NiV entry is inhibited by constructions and drugs specific for the endocytic pathway of macropinocytosis. Our findings could potentially permit the rapid development of novel low-cost antiviral treatments not only for NiV but also HeV.

  6. Sulforaphane is a Nrf2-independent inhibitor of mitochondrial fission

    Directory of Open Access Journals (Sweden)

    Gary B. O'Mealey

    2017-04-01

    Full Text Available The KEAP1-Nrf2-ARE antioxidant system is a principal means by which cells respond to oxidative and xenobiotic stresses. Sulforaphane (SFN, an electrophilic isothiocyanate derived from cruciferous vegetables, activates the KEAP1-Nrf2-ARE pathway and has become a molecule-of-interest in the treatment of diseases in which chronic oxidative stress plays a major etiological role. We demonstrate here that the mitochondria of cultured, human retinal pigment epithelial (RPE-1 cells treated with SFN undergo hyperfusion that is independent of both Nrf2 and its cytoplasmic inhibitor KEAP1. Mitochondrial fusion has been reported to be cytoprotective by inhibiting pore formation in mitochondria during apoptosis, and consistent with this, we show Nrf2-independent, cytoprotection of SFN-treated cells exposed to the apoptosis-inducer, staurosporine. Mechanistically, SFN mitigates the recruitment and/or retention of the soluble fission factor Drp1 to mitochondria and to peroxisomes but does not affect overall Drp1 abundance. These data demonstrate that the beneficial properties of SFN extend beyond activation of the KEAP1-Nrf2-ARE system and warrant further interrogation given the current use of this agent in multiple clinical trials.

  7. Why Does Bureaucratic Corruption Occur in the EU?

    DEFF Research Database (Denmark)

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2013-01-01

    Why does bureaucratic corruption occur in the EU system? Several examples suggest that bureaucratic corruption exists and that the Commission’s anti-fraud agency, OLAF, is not a fully independent authority. We thus develop a novel interpretation of the principalsupervisor-agent model to cope...... with non-independent anti-fraud units. This model shows that corruption is likely to occur when the expected value to the client from bribing the agent is larger than the expected value to the principal of truth-telling by the supervisor. Overall, this analysis points to the risks of flawed incentives...

  8. Oxidation and reduction of pyridine nucleotides in alamethicin-permeabilized plant mitochondria

    DEFF Research Database (Denmark)

    Johansson, F.I.; Michalecka, A.M.; Møller, I.M.

    2004-01-01

    method to permearbilize mitochondria and study the highly branched electron-transport chain in potato tuber (Solanum tuberosum) and pea leaf (Pisum sativum) mitochondria. We show that AlaM permeabilized the inner membrane of plant mitochondria to NAD(P)H, allowing the quantification of internal NAD......M-treated mitochondria was much higher than what has been previously measured by other techniques. Our results also show a difference in substrate specificities for complex I in mitochondria as compared with inside-out submitochondrial particles. AlaM facilitated the passage of cofactors to and from the mitochondrial...... environment not only in plant mitochondria but also in other membrane-enclosed compartments, such as intact cells, chloroplasts and peroxisomes....

  9. Improving oocyte quality by transfer of autologous mitochondria from fully grown oocytes

    DEFF Research Database (Denmark)

    Kristensen, Stine Gry; Pors, Susanne Elisabeth; Andersen, Claus Yding

    2017-01-01

    options using autologous mitochondria to potentially augment pregnancy potential in ART. Autologous transfer of mitochondria from the patient's own germline cells has attracted much attention as a possible new treatment to revitalize deficient oocytes. IVF births have been reported after transfer...... of oogonial precursor cell-derived mitochondria; however, the source and quality of the mitochondria are still unclear. In contrast, fully grown oocytes are loaded with mitochondria which have passed the genetic bottleneck and are likely to be of high quality. An increased supply of such oocytes could...... with high quality mitochondria can be obtained from natural or stimulated ovaries and potentially be used to improve both quality and quantity of oocytes available for fertility treatment....

  10. Human cultured cells are capable to incorporate isolated plant mitochondria loaded with exogenous DNA

    Directory of Open Access Journals (Sweden)

    Laktionov P. P.

    2012-07-01

    Full Text Available Aim. To investigate the possibility of human cultured cells to incorporate isolated mitochondria together with exogenous DNA introduced into organelles. Methods. Two approaches were used for this purpose, fluorescent labelling of mitochondria and/or DNA with subsequent analysis of the cells subjected to incubation by microscopy or by quantitative PCR. Results. We have shown that human cultured cells lines, HeLa and HUVEC, are capable to uptake isolated plant mitochondria and that this process depends on the incubation time and concentration of organelles present in medium. The incorporated mitochondria can serve as vehicles to deliver exogenous DNA into human cells, this DNA is then distributed in different cell compartments. Conclusions. These results are preliminary and need further investigations, including testing the possibility of human cells to incorporate the mitochondria of human or animal origin and creating genetic construction which could provide certain selectivity or stability of the transferred exogenous DNA upon cell uptake of the mitochondria as vectors.

  11. Melatonin promotes Bax sequestration to mitochondria reducing cell susceptibility to apoptosis via the lipoxygenase metabolite 5-hydroxyeicosatetraenoic acid

    KAUST Repository

    Radogna, Flavia

    2015-03-01

    Extra-neurological functions of melatonin include control of the immune system and modulation of apoptosis. We previously showed that melatonin inhibits the intrinsic apoptotic pathway in leukocytes via stimulation of high affinity MT1/MT2 receptors, thereby promoting re-localization of the anti-apoptotic Bcl-2 protein to mitochondria. Here we show that Bcl-2 sequesters pro-apoptotic Bax into mitochondria in an inactive form after melatonin treatment, thus reducing cell propensity to apoptosis. Bax translocation and the anti-apoptotic effect of melatonin are strictly dependent on the presence of Bcl-2, and on the 5-lipoxygenase (5-LOX) metabolite 5-hydroxyeicosatetraenoic acid (5-HETE), which we have previously shown to be produced as a consequence of melatonin binding to its low affinity target calmodulin. Therefore, the anti-apoptotic effect of melatonin requires the simultaneous, independent interaction with high (MT1/MT2) and low (calmodulin) affinity targets, eliciting two independent signal transduction pathways converging into Bax sequestration and inactivation. MT1/MT2 vs. lipoxygenase pathways are activated by 10-9 vs. 10-5M melatonin, respectively; the anti-apoptotic effect of melatonin is achieved at 10-5M, but drops to 10-9M upon addition of exogenous 5-HETE, revealing that lipoxygenase activation is the rate-limiting pathway. Therefore, in areas of inflammation with increased 5-HETE levels, physiological nanomolar concentrations of melatonin may suffice to maintain leukocyte viability.

  12. Preservation of skeletal muscle mitochondrial content in older adults: relationship between mitochondria, fibre type and high-intensity exercise training.

    Science.gov (United States)

    Wyckelsma, Victoria L; Levinger, Itamar; McKenna, Michael J; Formosa, Luke E; Ryan, Michael T; Petersen, Aaron C; Anderson, Mitchell J; Murphy, Robyn M

    2017-06-01

    Ageing is associated with an upregulation of mitochondrial dynamics proteins mitofusin 2 (Mfn2) and mitochondrial dynamics protein 49 (MiD49) in human skeletal muscle with the increased abundance of Mfn2 being exclusive to type II muscle fibres. These changes occur despite a similar content of mitochondria, as measured by COXIV, NDUFA9 and complexes in their native states (Blue Native PAGE). Following 12 weeks of high-intensity training (HIT), older adults exhibit a robust increase in mitochondria content, while there is a decline in Mfn2 in type II fibres. We propose that the upregulation of Mfn2 and MiD49 with age may be a protective mechanism to protect against mitochondrial dysfunction, in particularly in type II skeletal muscle fibres, and that exercise may have a unique protective effect negating the need for an increased turnover of mitochondria. Mitochondrial dynamics proteins are critical for mitochondrial turnover and maintenance of mitochondrial health. High-intensity interval training (HIT) is a potent training modality shown to upregulate mitochondrial content in young adults but little is known about the effects of HIT on mitochondrial dynamics proteins in older adults. This study investigated the abundance of protein markers for mitochondrial dynamics and mitochondrial content in older adults compared to young adults. It also investigated the adaptability of mitochondria to 12 weeks of HIT in older adults. Both older and younger adults showed a higher abundance of mitochondrial respiratory chain subunits COXIV and NDUFA9 in type I compared with type II fibres, with no difference between the older adults and young groups. In whole muscle homogenates, older adults had higher mitofusin-2 (Mfn2) and mitochondrial dynamics protein 49 (MiD49) contents compared to the young group. Also, older adults had higher levels of Mfn2 in type II fibres compared with young adults. Following HIT in older adults, MiD49 and Mfn2 levels were not different in whole

  13. NIF-type iron-sulfur cluster assembly system is duplicated and distributed in the mitochondria and cytosol of Mastigamoeba balamuthi.

    Science.gov (United States)

    Nývltová, Eva; Šuták, Robert; Harant, Karel; Šedinová, Miroslava; Hrdy, Ivan; Paces, Jan; Vlček, Čestmír; Tachezy, Jan

    2013-04-30

    In most eukaryotes, the mitochondrion is the main organelle for the formation of iron-sulfur (FeS) clusters. This function is mediated through the iron-sulfur cluster assembly machinery, which was inherited from the α-proteobacterial ancestor of mitochondria. In Archamoebae, including pathogenic Entamoeba histolytica and free-living Mastigamoeba balamuthi, the complex iron-sulfur cluster machinery has been replaced by an ε-proteobacterial nitrogen fixation (NIF) system consisting of two components: NifS (cysteine desulfurase) and NifU (scaffold protein). However, the cellular localization of the NIF system and the involvement of mitochondria in archamoebal FeS assembly are controversial. Here, we show that the genes for both NIF components are duplicated within the M. balamuthi genome. One paralog of each protein contains an amino-terminal extension that targets proteins to mitochondria (NifS-M and NifU-M), and the second paralog lacks a targeting signal, thereby reflecting the cytosolic form of the NIF machinery (NifS-C and NifU-C). The dual localization of the NIF system corresponds to the presence of FeS proteins in both cellular compartments, including detectable hydrogenase activity in Mastigamoeba cytosol and mitochondria. In contrast, E. histolytica possesses only single genes encoding NifS and NifU, respectively, and there is no evidence for the presence of the NIF machinery in its reduced mitochondria. Thus, M. balamuthi is unique among eukaryotes in that its FeS cluster formation is mediated through two most likely independent NIF machineries present in two cellular compartments.

  14. Role of the mitochondria in immune-mediated apoptotic death of the human pancreatic β cell line βLox5.

    Directory of Open Access Journals (Sweden)

    Yaíma L Lightfoot

    Full Text Available Mitochondria are indispensable in the life and death of many types of eukaryotic cells. In pancreatic beta cells, mitochondria play an essential role in the secretion of insulin, a hormone that regulates blood glucose levels. Unregulated blood glucose is a hallmark symptom of diabetes. The onset of Type 1 diabetes is preceded by autoimmune-mediated destruction of beta cells. However, the exact role of mitochondria has not been assessed in beta cell death. In this study, we examine the role of mitochondria in both Fas- and proinflammatory cytokine-mediated destruction of the human beta cell line, βLox5. IFNγ primed βLox5 cells for apoptosis by elevating cell surface Fas. Consequently, βLox5 cells were killed by caspase-dependent apoptosis by agonistic activation of Fas, but only after priming with IFNγ. This beta cell line undergoes both apoptotic and necrotic cell death after incubation with the combination of the proinflammatory cytokines IFNγ and TNFα. Additionally, both caspase-dependent and -independent mechanisms that require proper mitochondrial function are involved. Mitochondrial contributions to βLox5 cell death were analyzed using mitochondrial DNA (mtDNA depleted βLox5 cells, or βLox5 ρ(0 cells. βLox5 ρ(0 cells are not sensitive to IFNγ and TNFα killing, indicating a direct role for the mitochondria in cytokine-induced cell death of the parental cell line. However, βLox5 ρ(0 cells are susceptible to Fas killing, implicating caspase-dependent extrinsic apoptotic death is the mechanism by which these human beta cells die after Fas ligation. These data support the hypothesis that immune mediators kill βLox5 cells by both mitochondrial-dependent intrinsic and caspase-dependent extrinsic pathways.

  15. Computational properties of mitochondria in T cell activation and fate.

    Science.gov (United States)

    Uzhachenko, Roman; Shanker, Anil; Dupont, Geneviève

    2016-11-01

    In this article, we review how mitochondrial Ca 2+ transport (mitochondrial Ca 2+ uptake and Na + /Ca 2+ exchange) is involved in T cell biology, including activation and differentiation through shaping cellular Ca 2+ signals. Based on recent observations, we propose that the Ca 2+ crosstalk between mitochondria, endoplasmic reticulum and cytoplasm may form a proportional-integral-derivative (PID) controller. This PID mechanism (which is well known in engineering) could be responsible for computing cellular decisions. In addition, we point out the importance of analogue and digital signal processing in T cell life and implication of mitochondrial Ca 2+ transport in this process. © 2016 The Authors.

  16. An ancestral bacterial division system is widespread in eukaryotic mitochondria

    Czech Academy of Sciences Publication Activity Database

    Leger, M.M.; Petrů, M.; Žárský, V.; Eme, L.; Vlček, Čestmír; Harding, T.; Lang, B.F.; Eliáš, M.; Doležal, P.; Roger, A. J.

    2015-01-01

    Roč. 112, č. 33 (2015), s. 10239-10246 ISSN 0027-8424 R&D Projects: GA ČR GA13-24983S; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:GA ČR GA13-29423S; GA MŠk(CZ) CZ.1.05/1.1.00/02.0109 Institutional support: RVO:68378050 Keywords : mitochondria * Min proteins * MinCDE * mitochondrial fission * mitochondrial division Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.423, year: 2015

  17. The role of mitochondria in carbon catabolite repression in yeast.

    Science.gov (United States)

    Haussmann, P; Zimmermann, F K

    1976-10-18

    The role of mitochondria in carbon catabolite repression in Saccharomyces cerevisiae was investigated by comparing normal, respiratory competent (RHO) strains with their mitochondrially inherited, respiratory deficient mutant derivatives (rho). Formation of maltase and invertase was used as an indicator system for the effect of carbon catabolite repression on carbon catabolic reactions. Fermentation rates for glucose, maltose and sucrose were the same in RHO and rho strains. Specific activities of maltase and invertase were usually higher in the rho-mutants. A very pronounced difference in invertase levels was observed when cells were grown on maltose; rho-mutants had around 30 times more invertase than their RHO parent strains. The fact that rho-mutants were much less sensitive to carbon catabolite repression of invertase synthesis than their RHO parents was used to search for the mitochondrial factor(s) or function(s) involved in carbon catabolite repression. A possible metabolic influence of mitochondria on this system of regulation was tested after growth of RHO strains under anaerobic conditions (no respiration nor oxidative phosphorylation), in the presence of KCN (respiration inhibited), dinitrophenol (uncoupling of oxidative phosphorylation) and of both inhibitors anaerobic conditions and dinitrophenol had no effect on the extent of invertase repression. KCN reduced the degree of repression but not to the level found in rho-mutants. A combination of both inhibitors gave the same results as with KCN alone. Erythromycin and chloramphenicol were used as specific inhibitors of mitochondrial protein synthesis. Erythromycin prevented the formation of mitochondrial respiratory systems but did not induce rho-mutants under the conditions used. However, repression of invertase was as strong as in the absence of the inhibitor. Chloramphenicol led only to a slight reduction of the respiratory systems and did not affect invertase levels. A combination of both

  18. Aging changes of macromolecular synthesis in the mitochondria of mouse hepatocytes as revealed by microscopic radioautography

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Tetsuji [Shinshu University, Matsumoto (Japan). Dept. of Anatomy and Cell Biology

    2007-07-01

    This mini-review reports aging changes of macromolecular synthesis in the mitochondria of mouse hepatocytes. We have observed the macromolecular synthesis, such as DNA, RNA and proteins, in the mitochondria of various mammalian cells by means of electron microscopic radioautography technique developed in our laboratory. The number of mitochondria per cell, number of labeled mitochondria per cell with 3H-thymidine, 3H-uridine and 3H-leucine, precursors for DNA, RNA and proteins, respectively, were counted and the labeling indices at various ages, from fetal to postnatal early days and several months to 1 and 2 years in senescence, were calculated, which showed variations due to aging. (author)

  19. Rapid efflux of Ca2+ from heart mitochondria in the presence of inorganic pyrophosphate.

    Science.gov (United States)

    Vercesi, A; Lehninger, A L

    1984-01-13

    Inorganic pyrophosphate (PPi) in the intracellular concentration range causes rapid efflux of Ca2+ from rat heart mitochondria oxidizing pyruvate + malate in a low Na+ medium. Half-maximal rates of Ca2+ efflux were given by 20 microM PPi. During and after PPi-stimulated Ca2+ efflux the mitochondria retain their structural integrity and complete respiratory control. Carboxyatractyloside inhibits PPi-stimulated Ca2+ efflux, indicating PPi must enter the matrix in order to promote Ca2+ efflux. Heart mitochondria have a much higher affinity for PPi uptake and PPi-induced Ca2+ efflux than liver mitochondria.

  20. Tributyltin induces apoptotic signaling in hepatocytes through pathways involving the endoplasmic reticulum and mitochondria

    International Nuclear Information System (INIS)

    Grondin, Melanie; Marion, Michel; Denizeau, Francine; Averill-Bates, Diana A.

    2007-01-01

    Tri-n-butyltin is a widespread environmental toxicant, which accumulates in the liver. This study investigates whether tri-n-butyltin induces pro-apoptotic signaling in rat liver hepatocytes through pathways involving the endoplasmic reticulum and mitochondria. Tri-n-butyltin activated the endoplasmic reticulum pathway of apoptosis, which was demonstrated by the activation of the protease calpain, its translocation to the plasma membrane, followed by cleavage of the calpain substrates, cytoskeletal protein vinculin, and caspase-12. Caspase-12 is localized to the cytoplasmic side of the endoplasmic reticulum and is involved in apoptosis mediated by the endoplasmic reticulum. Tri-n-butyltin also caused translocation of the pro-apoptotic proteins Bax and Bad from the cytosol to mitochondria, as well as changes in mitochondrial membrane permeability, events which can activate the mitochondrial death pathway. Tri-n-butyltin induced downstream apoptotic events in rat hepatocytes at the nuclear level, detected by chromatin condensation and by confocal microscopy using acridine orange. We investigated whether the tri-n-butyltin-induced pro-apoptotic events in hepatocytes could be linked to perturbation of intracellular calcium homeostasis, using confocal microscopy. Tri-n-butyltin caused changes in intracellular calcium distribution, which were similar to those induced by thapsigargin. Calcium was released from a subcellular compartment, which is likely to be the endoplasmic reticulum, into the cytosol. Cytosolic acidification, which is known to trigger apoptosis, also occurred and involved the Cl - /HCO 3 - exchanger. Pro-apoptotic events in hepatocytes were inhibited by the calcium chelator, Bapta-AM, and by a calpain inhibitor, which suggests that changes in intracellular calcium homeostasis are involved in tri-n-butyltin-induced apoptotic signaling in rat hepatocytes

  1. Euglena mitochondria and chloroplasts form tyrosine-O-sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Saidha, T.; Hanfstingl, U.; Schiff, J.A. (Brandeis Univ., Waltham, MA (USA))

    1989-04-01

    Mitochondria from light-grown wild-type Euglena gracilis var. bacillaris Cori or dark-grown mutant W{sub 10}BSmL incubated with {sup 35}SO{sub 4}{sup 2{minus}} and ATP, or with {sup 14}C-tyrosine, non-radioactive sulfate and ATP accumulate a labeled compound in the medium. Since this compound shows exact coelectrophoresis with tyrosine-O-sulfate (TOS) at pH 2.0, 5.8 or 8.0., yields sulfate and tyrosine on acid hydrolysis, and treatment with aryl sulfatase from Aerobacter aerogenes yields sulfate and tyrosine but no tyrosine methyl ester, it is identified as TOS. No TOS is found outside purified developing chloroplasts incubated with {sup 35}SO{sub 4}{sup 2{minus}} and ATP, but both chloroplasts and mitochondria form to {sup 35}S externally when incubated with adenosine 3{prime} phosphate 5{prime}phospho({sup 35}S) sulfate (PAP{sup 35}S). Since no tyrosine need be added, tyrosine is provided from endogenous sources. Although TOS is found in the free pool of Euglena cells it cannot be detected in proteins of cells or mucus ruling our sulfation of tyrosine of protein or incorporation of TOS into proteins. The system forming TOS is membrane-bound and may be involved in tyrosine transport.

  2. Pluripotent Stem Cell Metabolism and Mitochondria: Beyond ATP

    Directory of Open Access Journals (Sweden)

    Jarmon G. Lees

    2017-01-01

    Full Text Available Metabolism is central to embryonic stem cell (ESC pluripotency and differentiation, with distinct profiles apparent under different nutrient milieu, and conditions that maintain alternate cell states. The significance of altered nutrient availability, particularly oxygen, and metabolic pathway activity has been highlighted by extensive studies of their impact on preimplantation embryo development, physiology, and viability. ESC similarly modulate their metabolism in response to altered metabolite levels, with changes in nutrient availability shown to have a lasting impact on derived cell identity through the regulation of the epigenetic landscape. Further, the preferential use of glucose and anaplerotic glutamine metabolism serves to not only support cell growth and proliferation but also minimise reactive oxygen species production. However, the perinuclear localisation of spherical, electron-poor mitochondria in ESC is proposed to sustain ESC nuclear-mitochondrial crosstalk and a mitochondrial-H2O2 presence, to facilitate signalling to support self-renewal through the stabilisation of HIFα, a process that may be favoured under physiological oxygen. The environment in which a cell is grown is therefore a critical regulator and determinant of cell fate, with metabolism, and particularly mitochondria, acting as an interface between the environment and the epigenome.

  3. Action of diclofenac on kidney mitochondria and cells

    International Nuclear Information System (INIS)

    Ng, Lin Eng; Vincent, Annette S.; Halliwell, Barry; Wong, Kim Ping

    2006-01-01

    The mitochondrial membrane potential measured in isolated rat kidney mitochondria and in digitonin-permeabilized MDCK type II cells pre-energized with succinate, glutamate, and/or malate was reduced by micromolar diclofenac dose-dependently. However, ATP biosynthesis from glutamate/malate was significantly more compromised compared to that from succinate. Inhibition of the malate-aspartate shuttle by diclofenac with a resultant decrease in the ability of mitochondria to generate NAD(P)H was demonstrated. Diclofenac however had no effect on the activities of NADH dehydrogenase, glutamate dehydrogenase, and malate dehydrogenase. In conclusion, decreased NAD(P)H production due to an inhibition of the entry of malate and glutamate via the malate-aspartate shuttle explained the more pronounced decreased rate of ATP biosynthesis from glutamate and malate by diclofenac. This drug, therefore affects the bioavailability of two major respiratory complex I substrates which would normally contribute substantially to supplying the reducing equivalents for mitochondrial electron transport for generation of ATP in the renal cell

  4. Targeting Mitochondria to Counteract Age-Related Cellular Dysfunction

    Directory of Open Access Journals (Sweden)

    Corina T. Madreiter-Sokolowski

    2018-03-01

    Full Text Available Senescence is related to the loss of cellular homeostasis and functions, which leads to a progressive decline in physiological ability and to aging-associated diseases. Since mitochondria are essential to energy supply, cell differentiation, cell cycle control, intracellular signaling and Ca2+ sequestration, fine-tuning mitochondrial activity appropriately, is a tightrope walk during aging. For instance, the mitochondrial oxidative phosphorylation (OXPHOS ensures a supply of adenosine triphosphate (ATP, but is also the main source of potentially harmful levels of reactive oxygen species (ROS. Moreover, mitochondrial function is strongly linked to mitochondrial Ca2+ homeostasis and mitochondrial shape, which undergo various alterations during aging. Since mitochondria play such a critical role in an organism’s process of aging, they also offer promising targets for manipulation of senescent cellular functions. Accordingly, interventions delaying the onset of age-associated disorders involve the manipulation of mitochondrial function, including caloric restriction (CR or exercise, as well as drugs, such as metformin, aspirin, and polyphenols. In this review, we discuss mitochondria’s role in and impact on cellular aging and their potential to serve as a target for therapeutic interventions against age-related cellular dysfunction.

  5. Mitochondria and Reactive Oxygen Species: Physiology and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Subhashini Bolisetty

    2013-03-01

    Full Text Available The air that we breathe contains nearly 21% oxygen, most of which is utilized by mitochondria during respiration. While we cannot live without it, it was perceived as a bane to aerobic organisms due to the generation of reactive oxygen and nitrogen metabolites by mitochondria and other cellular compartments. However, this dogma was challenged when these species were demonstrated to modulate cellular responses through altering signaling pathways. In fact, since this discovery of a dichotomous role of reactive species in immune function and signal transduction, research in this field grew at an exponential pace and the pursuit for mechanisms involved began. Due to a significant number of review articles present on the reactive species mediated cell death, we have focused on emerging novel pathways such as autophagy, signaling and maintenance of the mitochondrial network. Despite its role in several processes, increased reactive species generation has been associated with the origin and pathogenesis of a plethora of diseases. While it is tempting to speculate that anti-oxidant therapy would protect against these disorders, growing evidence suggests that this may not be true. This further supports our belief that these reactive species play a fundamental role in maintenance of cellular and tissue homeostasis.

  6. Adenine nucleotide translocator transports haem precursors into mitochondria.

    Directory of Open Access Journals (Sweden)

    Motoki Azuma

    2008-08-01

    Full Text Available Haem is a prosthetic group for haem proteins, which play an essential role in oxygen transport, respiration, signal transduction, and detoxification. In haem biosynthesis, the haem precursor protoporphyrin IX (PP IX must be accumulated into the mitochondrial matrix across the inner membrane, but its mechanism is largely unclear. Here we show that adenine nucleotide translocator (ANT, the inner membrane transporter, contributes to haem biosynthesis by facilitating mitochondrial accumulation of its precursors. We identified that haem and PP IX specifically bind to ANT. Mitochondrial uptake of PP IX was inhibited by ADP, a known substrate of ANT. Conversely, ADP uptake into mitochondria was competitively inhibited by haem and its precursors, suggesting that haem-related porphyrins are accumulated into mitochondria via ANT. Furthermore, disruption of the ANT genes in yeast resulted in a reduction of haem biosynthesis by blocking the translocation of haem precursors into the matrix. Our results represent a new model that ANT plays a crucial role in haem biosynthesis by facilitating accumulation of its precursors into the mitochondrial matrix.

  7. Slower Dynamics and Aged Mitochondria in Sporadic Alzheimer's Disease

    Science.gov (United States)

    Gargini, Ricardo; García, Esther; Perry, George

    2017-01-01

    Sporadic Alzheimer's disease corresponds to 95% of cases whose origin is multifactorial and elusive. Mitochondrial dysfunction is a major feature of Alzheimer's pathology, which might be one of the early events that trigger downstream principal events. Here, we show that multiple genes that control mitochondrial homeostasis, including fission and fusion, are downregulated in Alzheimer's patients. Additionally, we demonstrate that some of these dysregulations, such as diminished DLP1 levels and its mitochondrial localization, as well as reduced STOML2 and MFN2 fusion protein levels, take place in fibroblasts from sporadic Alzheimer's disease patients. The analysis of mitochondrial network disruption using CCCP indicates that the patients' fibroblasts exhibit slower dynamics and mitochondrial membrane potential recovery. These defects lead to strong accumulation of aged mitochondria in Alzheimer's fibroblasts. Accordingly, the analysis of autophagy and mitophagy involved genes in the patients demonstrates a downregulation indicating that the recycling mechanism of these aged mitochondria might be impaired. Our data reinforce the idea that mitochondrial dysfunction is one of the key early events of the disease intimately related with aging. PMID:29201274

  8. Independence and Product Systems

    OpenAIRE

    Skeide, Michael

    2003-01-01

    Starting from elementary considerations about independence and Markov processes in classical probability we arrive at the new concept of conditional monotone independence (or operator-valued monotone independence). With the help of product systems of Hilbert modules we show that monotone conditional independence arises naturally in dilation theory.

  9. Dexamethasone-induced radioresistance occurring independent of human papilloma virus gene expression in cervical carcinoma cells

    International Nuclear Information System (INIS)

    Rutz, H.P.; Mariotta, M.; Mirimanoff, R.O.; Knebel Doeberitz, M. von

    1998-01-01

    The aim of this study was to investigate the role of HPV 18 E6 and E7 gene products with respect to radiosensitivity of two cervical carcinoma cell lines. The two cervical carcinoma lines C4-1 and SW 756 were used in which treatment with dexamethasone allows to modulate expression levels of HPV 18 E6 and E7 genes: Upregulation in C4-1, down-regulation in SW 756. Effects of treatment with dexamethasone on plating efficiency and radiosensitivity were assessed using a clonogenic assay. Treatment with dexamethasone increased plating efficiency of the C4-1 cells, but did not affect plating efficiency of SW 756 cells. Treatment with dexamethasone induced enhanced radioresistance in both cell lines. Thus, in C4-1 cells the observed changes in radioresistance correlate to the enhancement in expression of HPV 18 genes E6/E7, whereas in SW 756, a reduced expression correlates negatively with the enhanced radioresistance. (orig./MG) [de

  10. Dexamethasone-induced radioresistance occurring independent of human papilloma virus gene expression in cervical carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Rutz, H.P.; Mariotta, M.; Mirimanoff, R.O. [Lab. de Radiobiologie, Service de Radio-Oncologie, CHUV, Lausanne (Switzerland); Knebel Doeberitz, M. von [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Inst. fuer Virusforschung

    1998-02-01

    The aim of this study was to investigate the role of HPV 18 E6 and E7 gene products with respect to radiosensitivity of two cervical carcinoma cell lines. The two cervical carcinoma lines C4-1 and SW 756 were used in which treatment with dexamethasone allows to modulate expression levels of HPV 18 E6 and E7 genes: Upregulation in C4-1, down-regulation in SW 756. Effects of treatment with dexamethasone on plating efficiency and radiosensitivity were assessed using a clonogenic assay. Treatment with dexamethasone increased plating efficiency of the C4-1 cells, but did not affect plating efficiency of SW 756 cells. Treatment with dexamethasone induced enhanced radioresistance in both cell lines. Thus, in C4-1 cells the observed changes in radioresistance correlate to the enhancement in expression of HPV 18 genes E6/E7, whereas in SW 756, a reduced expression correlates negatively with the enhanced radioresistance. (orig./MG) [Deutsch] Das Ziel dieser Studie lag darin, die Rolle der HPV-18-Gene E6 und E7 in bezug auf die Strahlenempfindlichkeit von menschlichen Zervixkarzinomzellen zu untersuchen. Wir verwendeten zwei menschliche Zervixkarzinomzellinien, C4-1 und SW 756, in welchen die Expression der viralen Gene HPV 18 E6 und E7 mit Dexamethason moduliert werden kann: In C4-1 bewirkt die Behandlung mit Dexamethason eine Erhoehung der Expression dieser Gene, in SW 756 eine Verminderung. Die Wirkung auf die Wachstumsfaehigkeit der Zellen und auf die Wachstumshemmung durch die Bestrahlung wurde unter Verwendung eines klonogenen Assays bestimmt. Dexamethason bewirkte eine erhoehte Wachstumsfaehigkeit der C4-1 Zellen, ohne die Wachstumsfaehigkeit der SW-756-Zellen zu beeinflussen, wie schon frueher beschrieben. Die Resistenz beider Zellinien gegenueber Bestrahlung wurde erhoeht. Somit besteht in den C4-1-Zellen eine Korrelation der Expression der viralen Gene mit der Zunahme der Strahlenresistenz, wogegen in den SW-756-Zellen die Abnahme der Expression im Gegensatz zu einer Zunahme der Strahlenresistenz steht. (orig./MG)

  11. Shear-mediated dilation of the internal carotid artery occurs independent of hypercapnia

    DEFF Research Database (Denmark)

    Hoiland, Ryan L; Smith, Kurt J; Carter, Howard Henry

    2017-01-01

    preceded increases in diameter in both transient (time: 16.8 ± 13.2 vs. 59.4 ± 60.3 s, P time: 18.2 ± 14.2 vs. 110.3 ± 79.6 s, P dilation was positively correlated with shear rate area under the curve in the transient (r2 = 0.44, P ...Evidence for shear stress as a regulator of carotid artery dilation in response to increased arterial CO2 was recently demonstrated in humans during sustained elevations in CO2 (hypercapnia); however, the relative contributions of CO2 and shear stress to this response remains unclear. We examined...... the hypothesis that, after a 30-s transient increase in arterial CO2 tension and consequent increase in internal carotid artery shear stress, internal carotid artery diameter would increase, indicating shear-mediated dilation, in the absence of concurrent hypercapnia. In 27 healthy participants, partial...

  12. Full establishment of arbuscular mycorrhizal symbiosis in rice occurs independently of enzymatic jasmonate biosynthesis.

    Directory of Open Access Journals (Sweden)

    Caroline Gutjahr

    Full Text Available Development of the mutualistic arbuscular mycorrhiza (AM symbiosis between most land plants and fungi of the Glomeromycota is regulated by phytohormones. The role of jasmonate (JA in AM colonization has been investigated in the dicotyledons Medicago truncatula, tomato and Nicotiana attenuata and contradicting results have been obtained with respect to a neutral, promotive or inhibitory effect of JA on AM colonization. Furthermore, it is currently unknown whether JA plays a role in AM colonization of monocotyledonous roots. Therefore we examined whether JA biosynthesis is required for AM colonization of the monocot rice. To this end we employed the rice mutant constitutive photomorphogenesis 2 (cpm2, which is deficient in JA biosynthesis. Through a time course experiment the amount and morphology of fungal colonization did not differ between wild-type and cpm2 roots. Furthermore, no significant difference in the expression of AM marker genes was detected between wild type and cpm2. However, treatment of wild-type roots with 50 μM JA lead to a decrease of AM colonization and this was correlated with induction of the defense gene PR4. These results indicate that JA is not required for AM colonization of rice but high levels of JA in the roots suppress AM development likely through the induction of defense.

  13. EST analysis on pig mitochondria reveal novel expression differences between developmental and adult tissues

    DEFF Research Database (Denmark)

    Scheibye-Alsing, Karsten; Cirera, Susanna; Gilchrist, Michael J.

    2007-01-01

    BACKGROUND: The mitochondria are involved in many basic functions in cells of vertebrates, and can be considered the power generator of the cell. Though the mitochondria have been extensively studied there appear to be only few expression studies of mitochondrial genes involving a large number...

  14. Cellular characterization of human dermal fibroblasts, focus on mitochondria and maple syrup urine disease

    DEFF Research Database (Denmark)

    Fernandez-Guerra, Paula

    and functions are expressed in HDFs’ culture environment. Studies of molecular disease mechanisms often point to the involvement of mitochondria. Mitochondria are involved in the regulation of cell cycle and programmed cell death as well as cellular stress responses because they are the main producers...

  15. Kidney outer medulla mitochondria are more efficient compared to cortex mitochondria as a strategy to sustain ATP production in a suboptimal environment.

    Science.gov (United States)

    Schiffer, Tomas A; Gustafsson, Håkan; Palm, Fredrik

    2018-05-30

    The kidneys receive approximately 25% of cardiac output, which is a prerequisite in order to maintain sufficient glomerular filtration rate. However, both intrarenal regional renal blood flow and tissue oxygen levels are heterogeneous with decreasing levels in the inner part of the medulla. These differences in combination with the heterogeneous metabolic activity of the different nephron segment located in the different parts of the kidney may constitute a functional problem when challenged. The proximal tubule and the medullary thick ascending limb of Henle are considered to have the highest metabolic rate, which is relating to the high mitochondria content needed to sustain sufficient ATP production from oxidative phosphorylation in order to support high electrolyte transport activity in these nephron segments. Interestingly, the cells located in kidney medulla functions at the verge of hypoxia and the mitochondria may have adapted to the surrounding environment. However, little is known about intrarenal differences in mitochondria function. We therefore investigated functional differences between mitochondria isolated from kidney cortex and medulla of healthy normoglycemic rats were estimated using high-resolution respirometry. The results demonstrate that medullary mitochondria had a higher degree of coupling, are more efficient and have higher oxygen affinity, which would make them more suitable to function in an environment with limited oxygen supply. Furthermore, these results support the hypothesis that mitochondria of medullary cells have adapted to the normal hypoxic in vivo situation as a strategy of sustaining ATP production in a suboptimal environment.

  16. Effects of Various Kynurenine Metabolites on Respiratory Parameters of Rat Brain, Liver and Heart Mitochondria

    Directory of Open Access Journals (Sweden)

    Halina Baran*

    2016-01-01

    Full Text Available Previously, we demonstrated that the endogenous glutamate receptor antagonist kynurenic acid dose-dependently and significantly affected rat heart mitochondria. Now we have investigated the effects of L-tryptophan, L-kynurenine, 3-hydroxykynurenine and kynurenic, anthranilic, 3-hydroxyanthranilic, xanthurenic and quinolinic acids on respiratory parameters (ie, state 2, state 3, respiratory control index (RC and ADP/oxygen ratio in brain, liver and heart mitochondria of adult rats. Mitochondria were incubated with glutamate/malate (5 mM or succinate (10 mM and in the presence of L-tryptophan metabolites (1 mM or in the absence, as control. Kynurenic and anthranilic acids significantly reduced RC values of heart mitochondria in the presence of glutamate/malate. Xanthurenic acid significantly reduced RC values of brain mitochondria in the presence of glutamate/malate. Furthermore, 3-hydroxykynurenine and 3-hydroxyanthranilic acid decreased RC values of brain, liver and heart mitochondria using glutamate/malate. In the presence of succinate, 3-hydroxykynurenine and 3-hydroxyanthranilic acid affected RC values of brain mitochondria, whereas in liver and heart mitochondria only 3-hydroxykynurenine lowered RC values significantly. Furthermore, lowered ADP/oxygen ratios were observed in brain mitochondria in the presence of succinate with 3-hydroxykynurenine and 3-hydroxyanthranilic acid, and to a lesser extent with glutamate/malate. In addition, 3-hydroxyanthranilic acid significantly lowered the ADP/oxygen ratio in heart mitochondria exposed to glutamate/malate, while in the liver mitochondria only a mild reduction was found. Tests of the influence of L-tryptophan and its metabolites on complex I in liver mitochondria showed that only 3-hydroxykynurenine, 3-hydroxyanthranilic acid and L-kynurenine led to a significant acceleration of NADH-driven complex I activities. The data indicate that L-tryptophan metabolites had different effects on brain, liver

  17. Gene introduction into the mitochondria of Arabidopsis thaliana via peptide-based carriers

    Science.gov (United States)

    Chuah, Jo-Ann; Yoshizumi, Takeshi; Kodama, Yutaka; Numata, Keiji

    2015-01-01

    Available methods in plant genetic transformation are nuclear and plastid transformations because similar procedures have not yet been established for the mitochondria. The double membrane and small size of the organelle, in addition to its large population in cells, are major obstacles in mitochondrial transfection. Here we report the intracellular delivery of exogenous DNA localized to the mitochondria of Arabidopsis thaliana using a combination of mitochondria-targeting peptide and cell-penetrating peptide. Low concentrations of peptides were sufficient to deliver DNA into the mitochondria and expression of imported DNA reached detectable levels within a short incubation period (12 h). We found that electrostatic interaction with the cell membrane is not a critical factor for complex internalization, instead, improved intracellular penetration of mitochondria-targeted complexes significantly enhanced gene transfer efficiency. Our results delineate a simple and effective peptide-based method, as a starting point for the development of more sophisticated plant mitochondrial transfection strategies.

  18. The fate of paternal mitochondria in marmoset pre-implantation embryos.

    Science.gov (United States)

    Luetjens, C M; Wesselmann, R

    2008-06-01

    Sperm-derived mitochondria are integrated into the oocyte at fertilization but seem to vanish during the early cleavage phase. The developmental potential of pre-implantation embryos seems to be closely related to their ability to induce degeneration of these mitochondria, but the mechanisms underlying their loss of function are not yet understood. This study focuses on the fate of paternal mitochondria in pre-implantation embryos. Stimulation, collection and in vitro culture of oocytes from Callithrix jacchus, allows the study of the destiny of paternal mitochondria by utilizing immunostaining of pre-implantation embryos, fluorescence and laserscanning microscopy. Live pre-implantation embryos were stained with a fluorescence indicator reflecting mitochondrial membrane potential. Evidence indicating the loss of mitochondrial function was not found nor that apoptosis pathways were involved in the disappearance of paternally derived mitochondria. These findings may have implications for mitochondrially inherited diseases and could lead to new strategies for improving assisted reproduction.

  19. Effect of sclerin on amino acid incorporation into mitochondria isolated from rat liver

    International Nuclear Information System (INIS)

    Yamaguchi, Masanori; Satomura, Yukio

    1975-01-01

    Though sclerin (SCL) stimulated amino acid incorporation into the protein fraction of post mitochondrial supernatant of rat liver homogenate, it had no effect on the incorporation into the isolated mitochondria at pH 7.2, despite of its stimulating effect on mitochondrial oxidative phosphorylation. SCL stimulated amino acid incorporation into the mitochondria at pH 6.1, and to some extent maintained the activity on that in mitochondria during aging in hypotonic Tris-HCl buffer (pH 7.2). Since SCL prevented leakage of amino acids from the mitochondria into these buffers, it was suggested that SCL may protect a structure of mitochondrial membrane which appeared to have a significance on transport of amino acids. In liver slices, SCL stimulated amino acid incorporation only into the extra-mitochondrial fraction for the first 3 min, but gradually turned to simulate incorporation into mitochondria within 30 min. (auth.)

  20. Uncoupling and oxidative stress in liver mitochondria isolated from rats with acute iron overload

    Energy Technology Data Exchange (ETDEWEB)

    Pardo Andreu, G.L. [Centro de Quimica Farmaceutica, Departamento de Investigaciones Biomedicas, Ciudad de La Habana (Cuba); Inada, N.M.; Vercesi, A.E. [Universidade Estadual de Campinas, Departamento de Patologia Clinica, Faculdade de Ciencias Medicas, Campinas, SP (Brazil); Curti, C. [Universidade de Sao Paulo, Departamento de Fisica e Quimica, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, SP (Brazil)

    2009-01-15

    One hypothesis for the etiology of cell damage arising from iron overload is that its excess selectively affects mitochondria. Here we tested the effects of acute iron overload on liver mitochondria isolated from rats subjected to a single dose of i.p. 500 mg/kg iron-dextran. The treatment increased the levels of iron in mitochondria (from 21{+-}4 to 130{+-}7 nmol/mg protein) and caused both lipid peroxidation and glutathione oxidation. The mitochondria of iron-treated rats showed lower respiratory control ratio in association with higher resting respiration. The mitochondrial uncoupling elicited by iron-treatment did not affect the phosphorylation efficiency or the ATP levels, suggesting that uncoupling is a mitochondrial protective mechanism against acute iron overload. Therefore, the reactive oxygen species (ROS)/H{sup +} leak couple, functioning as a mitochondrial redox homeostatic mechanism could play a protective role in the acutely iron-loaded mitochondria. (orig.)

  1. Specificity of DNA import into isolated mitochondria from plants and mammals

    Directory of Open Access Journals (Sweden)

    Koulintchenko M. V.

    2014-01-01

    Full Text Available Aim. Investigation of different features of DNA import into plant and human mitochondria, for a better understanding of mitochondrial genetics and generation of biotechnological tools. Methods. DNA up-take experiments with isolated plant mitochondria, using as substrates various sequences associated or not with the specific terminal inverted repeats (TIRs present at each end of the plant mitochondrial linear plasmids. Results. It was established that the DNA import efficiency has a non-linear dependence on DNA size. It was shown that import into plant mitochondria of DNA molecules of «medium» sizes, i. e. between 4 and 7 kb, barely has any sequence specificity: neither TIRs from the 11.6 kb Brassica plasmid, nor TIRs from the Zea mays S-plasmids influenced DNA import into Solanum tuberosum mitochondria. Conclusions. The data obtained support the hypothesis about species-specific import mechanism operating under the mitochondrial linear plasmids transfer into plant mitochondria.

  2. Nanopreparations for mitochondria targeting drug delivery system: Current strategies and future prospective

    Directory of Open Access Journals (Sweden)

    Zhenjie Wang

    2017-11-01

    Full Text Available Mitochondria are a novel and promising therapeutic target for diagnosis, treatment and prevention of a lot of human diseases such as cancer, metabolic diseases and neurodegenerative disease. Owing to the mitochondrial special bilayer structure and highly negative potential nature, therapeutic molecules have multiple difficulties in reaching mitochondria. To overcome multiple barriers for targeting mitochondria, the researchers developed various pharmaceutical preparations such as liposomes, polymeric nanoparticles and inorganic nanoparticles modified by mitochondriotropic moieties like dequalinium (DQA, triphenylphosphonium (TPP, mitochondrial penetrating peptides (MPPs and mitochondrial protein import machinery that allow specific targeting. The targeted formulations exhibited enhanced pharmacological effect and better therapeutic effect than their untargeted counterpart both in vitro and in vivo. Nanocarriers may be used for bio-therapeutic delivery into specific mitochondria that possess a great potential treatment of mitochondria related diseases.

  3. Effect of sclerin on amino acid incorporation into mitochondria isolated from rat liver

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, M; Satomura, Y [Osaka City Univ. (Japan). Faculty of Science

    1975-08-01

    Though sclerin (SCL) stimulated amino acid incorporation into the protein fraction of post mitochondrial supernatant of rat liver homogenate, it had no effect on the incorporation into the isolated mitochondria at pH 7.2, despite of its stimulating effect on mitochondrial oxidative phosphorylation. SCL stimulated amino acid incorporation into the mitochondria at pH 6.1, and to some extent maintained the activity on that in mitochondria during aging in hypotonic Tris-HCl buffer (pH 7.2). Since SCL prevented leakage of amino acids from the mitochondria into these buffers, it was suggested that SCL may protect a structure of mitochondrial membrane which appeared to have a significance on transport of amino acids. In liver slices, SCL stimulated amino acid incorporation only into the extra-mitochondrial fraction for the first 3 min, but gradually turned to simulate incorporation into mitochondria within 30 min.

  4. Huperzine A protects isolated rat brain mitochondria against beta-amyloid peptide.

    Science.gov (United States)

    Gao, Xin; Zheng, Chun Yan; Yang, Ling; Tang, Xi Can; Zhang, Hai Yan

    2009-06-01

    Our previous work in cells and animals showed that mitochondria are involved in the neuroprotective effect of huperzine A (HupA). In this study, the effects of HupA on isolated rat brain mitochondria were investigated. In addition to inhibiting the Abeta(25-35) (40 microM)-induced decrease in mitochondrial respiration, adenosine 5'-triphosphate (ATP) synthesis, enzyme activity, and transmembrane potential, HupA (0.01 or 0.1 microM) effectively prevented Abeta-induced mitochondrial swelling, reactive oxygen species increase, and cytochrome c release. More interestingly, administration of HupA to isolated mitochondria promoted the rate of ATP production and blocked mitochondrial swelling caused by normal osmosis. These results indicate that HupA protects mitochondria against Abeta at least in part by preserving membrane integrity and improving energy metabolism. These direct effects on mitochondria further extend the noncholinergic functions of HupA.

  5. UCP3 is associated with Hax-1 in mitochondria in the presence of calcium ion

    International Nuclear Information System (INIS)

    Hirasaka, Katsuya; Mills, Edward M.; Haruna, Marie; Bando, Aki; Ikeda, Chika; Abe, Tomoki; Kohno, Shohei; Nowinski, Sara M.; Lago, Cory U.; Akagi, Ken-ichi; Tochio, Hidehito; Ohno, Ayako; Teshima-Kondo, Shigetada; Okumura, Yuushi; Nikawa, Takeshi

    2016-01-01

    Uncoupling protein 3 (UCP3) is known to regulate energy dissipation, proton leakage, fatty acid oxidation, and oxidative stress. To identify the putative protein regulators of UCP3, we performed yeast two-hybrid screens. Here we report that UCP3 interacted with HS-1 associated protein X-1 (Hax-1), an anti-apoptotic protein that was localized in the mitochondria, and is involved in cellular responses to Ca"2"+. The hydrophilic sequences within loop 2, and the matrix-localized hydrophilic domain of mouse UCP3, were necessary for binding to Hax-1 at the C-terminal domain, adjacent to the mitochondrial inner membrane. Interestingly, interaction of these proteins occurred in a calcium-dependent manner. Moreover, the NMR spectrum of the C-terminal domain of Hax-1 was dramatically changed by removal of Ca"2"+, suggesting that the C-terminal domain of Hax-1 underwent a Ca"2"+-induced conformational change. In the Ca"2"+-free state, the C-terminal Hax-1 tended to unfold, suggesting that Ca"2"+ binding may induce protein folding of the Hax-1 C-terminus. These results suggested that the UCP3-Hax-1 complex may regulate mitochondrial functional changes caused by mitochondrial Ca"2"+. - Highlights: • UCP3 interacts with Hax-1. • The interaction of UCP3 and Hax-1 occurs in a calcium-dependent manner. • The C-terminal domain of Hax-1 undergoes a calcium-induced conformational change.

  6. Proteomic profiling of mitochondria: what does it tell us about the ageing brain?

    Science.gov (United States)

    Ingram, Thomas; Chakrabarti, Lisa

    2016-12-13

    Mitochondrial dysfunction is evident in numerous neurodegenerative and age-related disorders. It has also been linked to cellular ageing, however our current understanding of the mitochondrial changes that occur are unclear. Functional studies have made some progress reporting reduced respiration, dynamic structural modifications and loss of membrane potential, though there are conflicts within these findings. Proteomic analyses, together with functional studies, are required in order to profile the mitochondrial changes that occur with age and can contribute to unravelling the complexity of the ageing phenotype. The emergence of improved protein separation techniques, combined with mass spectrometry analyses has allowed the identification of age and cell-type specific mitochondrial changes in energy metabolism, antioxidants, fusion and fission machinery, chaperones, membrane proteins and biosynthesis pathways. Here, we identify and review recent data from the analyses of mitochondria from rodent brains. It is expected that knowledge gained from understanding age-related mitochondrial changes of the brain should lead to improved biomarkers of normal ageing and also age-related disease progression.

  7. Correlation between chloride flux via the mitochondria-rich cells and transepithelial water movement in isolated frog skin (Rana esculenta)

    DEFF Research Database (Denmark)

    Nielsen, Robert

    1995-01-01

    Antidiuretic hormone; chloride transport; electroosmosis; Frog skin; Intercalated cells; Local osmosis; Mitochondria-rich cells.......Antidiuretic hormone; chloride transport; electroosmosis; Frog skin; Intercalated cells; Local osmosis; Mitochondria-rich cells....

  8. Analysis of the behavior of mitochondria in the ovaries of the earthworm Dendrobaena veneta Rosa 1839.

    Directory of Open Access Journals (Sweden)

    Justyna Faron

    Full Text Available We examined six types of cells that form the ovary of the earthworm Dendrobena veneta ogonia, prooocytes, vitellogenic oocytes, trophocytes, fully grown postvitellogenic oocytes and somatic cells of the gonad. The quantitative stereological method revealed a much higher "volume density" of mitochondria in all of the types of germ-line cells except for the somatic cells. Fluorescent vital stain JC-1, however, showed a much higher oxidative activity of mitochondria in the somatic cells than in the germ-line cells. The distribution of active and inactive mitochondria within the studied cells was assessed using the computer program ImageJ. The analysis showed a higher luminosity of inactive mitochondria in all of the types of germ-line cells and a higher luminosity of active mitochondria in somatic cells. The OXPHOS activity was found in somatic cells mitochondria and in the peripheral mitochondria of the vitellogenic oocytes. The detection of reactive oxygen species (ROS revealed a differentiated distribution of ROS in the different cell types. The amount of ROS substances was lower in somatic cells than in younger germ-line cells. The ROS level was also low in the cytoplasm of fully grown postwitellogenic oocytes. The distribution of the MnSOD enzyme that protects mitochondria against destructive role of ROS substances was high in the oogonia and in prooocytes and it was very high in vitellogenic and postvitellogenic oocytes. However, a much lower level of this protective enzyme was observed in the trophocytes and the lowest level was found in the cytoplasm of somatic cells. The lower mitochondrial activity and higher level of MnSOD activity in germ-line cells when compared to somatic cells testifies to the necessity of the organisms to protect the mitochondria of oocytes against the destructive role of the ROS that are produced during oxidative phosphorylation. The protection of the mitochondria in oocytes is essential for the transfer of healthy

  9. Obesity-exposed oocytes accumulate and transmit damaged mitochondria due to an inability to activate mitophagy.

    Science.gov (United States)

    Boudoures, Anna L; Saben, Jessica; Drury, Andrea; Scheaffer, Suzanne; Modi, Zeel; Zhang, Wendy; Moley, Kelle H

    2017-06-01

    Mitochondria are the most prominent organelle in the oocyte. Somatic cells maintain a healthy population of mitochondria by degrading damaged mitochondria via mitophagy, a specialized autophagy pathway. However, evidence from previous work investigating the more general macroautophagy pathway in oocytes suggests that mitophagy may not be active in the oocyte. This would leave the vast numbers of mitochondria - poised to be inherited by the offspring - vulnerable to damage. Here we test the hypothesis that inactive mitophagy in the oocyte underlies maternal transmission of dysfunctional mitochondria. To determine whether oocytes can complete mitophagy, we used either CCCP or AntimycinA to depolarize mitochondria and trigger mitophagy. After depolarization, we did not detect co-localization of mitochondria with autophagosomes and mitochondrial DNA copy number remained unchanged, indicating the non-functional mitochondrial population was not removed. To investigate the impact of an absence of mitophagy in oocytes with damaged mitochondria on offspring mitochondrial function, we utilized in vitro fertilization of high fat high sugar (HF/HS)-exposed oocytes, which have lower mitochondrial membrane potential and damaged mitochondria. Here, we demonstrate that blastocysts generated from HF/HS oocytes have decreased mitochondrial membrane potential, lower metabolites involved in ATP generation, and accumulation of PINK1, a mitophagy marker protein. This mitochondrial phenotype in the blastocyst mirrors the phenotype we show in HF/HS exposed oocytes. Taken together, these data suggest that the mechanisms governing oocyte mitophagy are fundamentally distinct from those governing somatic cell mitophagy and that the absence of mitophagy in the setting of HF/HS exposure contributes to the oocyte-to-blastocyst transmission of dysfunctional mitochondria. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Involvement of S6K1 in mitochondria function and structure in HeLa cells.

    Science.gov (United States)

    Park, Jisoo; Tran, Quangdon; Mun, Kisun; Masuda, Kouhei; Kwon, So Hee; Kim, Seon-Hwan; Kim, Dong-Hoon; Thomas, George; Park, Jongsun

    2016-12-01

    The major biological function of mitochondria is to generate cellular energy through oxidative phosphorylation. Apart from cellular respiration, mitochondria also play a key role in signaling processes, including aging and cancer metabolism. It has been shown that S6K1-knockout mice are resistant to obesity due to enhanced beta-oxidation, with an increased number of large mitochondria. Therefore, in this report, the possible involvement of S6K1 in regulating mitochondria dynamics and function has been investigated in stable lenti-shS6K1-HeLa cells. Interestingly, S6K1-stably depleted HeLa cells showed phenotypical changes in mitochondria morphology. This observation was further confirmed by detailed image analysis of mitochondria shape. Corresponding molecular changes were also observed in these cells, such as the induction of mitochondrial fission proteins (Drp1 and Fis1). Oxygen consumption is elevated in S6K1-depeleted HeLa cells and FL5.12 cells. In addition, S6K1 depletion leads to enhancement of ATP production in cytoplasm and mitochondria. However, the relative ratio of mitochondrial ATP to cytoplasmic ATP is actually decreased in lenti-shS6K1-HeLa cells compared to control cells. Lastly, induction of mitophagy was found in lenti-shS6K1-HeLa cells with corresponding changes of mitochondria shape on electron microscope analysis. Taken together, our results indicate that S6K1 is involved in the regulation of mitochondria morphology and function in HeLa cells. This study will provide novel insights into S6K1 function in mitochondria-mediated cellular signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Dynamic movement of cytochrome c from mitochondria into cytosol and peripheral circulation in massive hepatic cell injury.

    Science.gov (United States)

    Kobayashi, Yoshinori; Mori, Masaaki; Naruto, Takuya; Kobayashi, Naoki; Sugai, Toshiyuki; Imagawa, Tomoyuki; Yokota, Shumpei

    2004-12-01

    In the process of apoptosis, it is known that the transition of cytochrome c from mitochondria into the cytosol occurs, and tumor necrosis factor (TNF)-alpha is one of the molecules responsible for this event. But in the state of hypercytokine induced by D-galactosamine (D-GaIN)/Lipopolysaccharide (LPS), the localization of cytochrome c is little known. Rats were administrated with D-GaIN(700 mg/kg)/LPS(200 microg/kg). Blood and tissue samples were collected and examined for levels of pro-inflammatory cytokines, the apoptosis of liver cells, and the localization of cytochrome c. Before administration of D-GaIN/LPS, cytochrome c was definitely localized in the mitochondria. At 2 h after simultaneous administration of D-GaIN/LPS, cytochrome c had accumulated in the cytosol following abrupt increases of plasma TNF-alpha. Massive cell destruction due to apoptosis proved by Terminal deoxynucleo-tidyl transferase-mediated dUTP nick end labeling staining was observed in liver tissue 4 h later and markedly increased levels of cytochrome c were detected in the plasma 12 h after D-GaIN/LPS administration. Liver injury induced by simultaneous administration of D-GaIN/LPS was closely associated with the production of TNF-alpha, and also with the dynamic movement of cytochrome c from the mitochondria into the cytosol, and then into the systemic circulation. The detection of plasma cytochrome c levels may be a useful clinical tool for the detection of apoptosis in vivo.

  12. Mitochondria, Cybrids, Aging, and Alzheimer’s Disease

    Science.gov (United States)

    Swerdlow, Russell H.; Koppel, Scott; Weidling, Ian; Hayley, Clay; Ji, Yan; Wilkins, Heather M.

    2018-01-01

    Mitochondrial and bioenergetic function change with advancing age and may drive aging phenotypes. Mitochondrial and bioenergetic changes are also documented in various age-related neurodegenerative diseases, including Alzheimer’s disease (AD). In some instances AD mitochondrial and bioenergetic changes are reminiscent of those observed with advancing age, but are greater in magnitude. Mitochondrial and bioenergetic dysfunction could, therefore, link neurodegeneration to brain aging. Interestingly, mitochondrial defects in AD patients are not brain-limited, and mitochondrial function can be linked to classic AD histologic changes including amyloid precursor protein processing to beta amyloid. Also, transferring mitochondria from AD subjects to cell lines depleted of endogenous mitochondrial DNA (mtDNA) creates cytoplasmic hybrid (cybrid) cell lines that recapitulate specific biochemical, molecular, and histologic AD features. Such findings have led to the formulation of a “mitochondrial cascade hypothesis” that places mitochondrial dysfunction at the apex of the AD pathology pyramid. Data pertinent to this premise are reviewed. PMID:28253988

  13. The genome and transcriptome of perennial ryegrass mitochondria

    DEFF Research Database (Denmark)

    Islam, Md. Shofiqul; Studer, Bruno; Byrne, Stephen

    2013-01-01

    Background: Perennial ryegrass (Lolium perenne L.) is one of the most important forage and turf grass species of temperate regions worldwide. Its mitochondrial genome is inherited maternally and contains genes that can influence traits of agricultural importance. Moreover, the DNA sequence...... and annotation of the complete mitochondrial genome from perennial ryegrass. Results: Intact mitochondria from perennial ryegrass leaves were isolated and used for mtDNA extraction. The mitochondrial genome was sequenced to a 167-fold coverage using the Roche 454 GS-FLX Titanium platform, and assembled...... of mitochondrial genomes has been established and compared for a large number of species in order to characterize evolutionary relationships.Therefore, it is crucial to understand the organization of the mitochondrial genome and how it varies between and within species. Here, we report the first de novo assembly...

  14. Sensitivity of mitochondria of the mouse liver cells to radiation

    International Nuclear Information System (INIS)

    Shima, Akihiro

    1974-01-01

    In order to study the sensitivity of mitochondria (Mt) of the liver cells to radiation, 0.4 mg of riboflavine (RF) was intraperitoneally injected into mice which had been fed RF deficient food for 13 weeks. Three hours later 400 R of X-ray (190 KVP, 25 mA, 0.5 mmCu, 0.5 mmAl filter, FSD 61.5 cm, and HVL 0.80 mmCu) were irradiated to the whole body, and giant Mt of the liver cells were observed. When the liver cells were observed 24 hours after injection, neither giant Mt nor mitotic findings of Mt were found. All Mt observed were small (1.2 μ), although mice received 400 R of X-ray. (Serizawa, K.)

  15. Sensitivity of mitochondria of the mouse liver cells to radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shima, A [Tokyo Univ. (Japan). Faculty of Science

    1974-06-01

    In order to study the sensitivity of mitochondria (Mt) of the liver cells to radiation, 0.4 mg of riboflavine (RF) was intraperitoneally injected into mice which had been fed RF deficient food for 13 weeks. Three hours later 400 R of X-ray (190 KVP, 25 mA, 0.5 mmCu, 0.5 mmAl filter, FSD 61.5 cm, and HVL 0.80 mmCu) were irradiated to the whole body, and giant Mt of the liver cells were observed. When the liver cells were observed 24 hours after injection, neither giant Mt nor mitotic findings of Mt were found. All Mt observed were small (1.2 ..mu..), although mice received 400 R of X-ray.

  16. Aerobic mitochondria of parasitic protists: Diverse genomes and complex functions.

    Science.gov (United States)

    Zíková, Alena; Hampl, Vladimír; Paris, Zdeněk; Týč, Jiří; Lukeš, Julius

    In this review the main features of the mitochondria of aerobic parasitic protists are discussed. While the best characterized organelles are by far those of kinetoplastid flagellates and Plasmodium, we also consider amoebae Naegleria and Acanthamoeba, a ciliate Ichthyophthirius and related lineages. The simplistic view of the mitochondrion as just a power house of the cell has already been abandoned in multicellular organisms and available data indicate that this also does not apply for protists. We discuss in more details the following mitochondrial features: genomes, post-transcriptional processing, translation, biogenesis of iron-sulfur complexes, heme metabolism and the electron transport chain. Substantial differences in all these core mitochondrial features between lineages are compatible with the view that aerobic protists harbor organelles that are more complex and flexible than previously appreciated. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Abnormal mitochondria in Rett syndrome: one case report.

    Science.gov (United States)

    Mak, S C; Chi, C S; Chen, C H; Shian, W J

    1993-08-01

    A 6-year-9-month-old girl with the characteristic features of Rett syndrome is reported. Clinically, she had microcephaly, psychomotor arrest, deterioration of communication, autistic behaviour, loss of language development, gait apraxia and stereotyped hand washing movement. Amino acid and organic acid analysis were normal. An abnormal rise in serum lactate was noted 120 minutes after oral glucose loading. Muscle biopsy was performed and there was no specific finding noted under light microscope. Electron microscopic evaluation revealed mild accumulation of mitochondria at subsarcolemmal area with abnormal tubular cristae. The cause of Rett syndrome remains obscure. Several articles concerning abnormal mitochondrial morphology or respiratory enzymes have been reported. The exact pathogenesis requires further investigation.

  18. Are Independent Fiscal Institutions Really Independent?

    Directory of Open Access Journals (Sweden)

    Slawomir Franek

    2015-08-01

    Full Text Available In the last decade the number of independent fiscal institutions (known also as fiscal councils has tripled. They play an important oversight role over fiscal policy-making in democratic societies, especially as they seek to restore public finance stability in the wake of the recent financial crisis. Although common functions of such institutions include a role in analysis of fiscal policy, forecasting, monitoring compliance with fiscal rules or costing of spending proposals, their roles, resources and structures vary considerably across countries. The aim of the article is to determine the degree of independence of such institutions based on the analysis of the independence index of independent fiscal institutions. The analysis of this index values may be useful to determine the relations between the degree of independence of fiscal councils and fiscal performance of particular countries. The data used to calculate the index values will be derived from European Commission and IMF, which collect sets of information about characteristics of activity of fiscal councils.

  19. The effect of the coupled oxidation of substrate on the permeability of blowfly flight-muscle mitochondria to potassium and other cations.

    Science.gov (United States)

    Hansford, R G; Lehninger, A L

    1972-02-01

    1. Blowfly flight-muscle mitochondria respiring in the absence of phosphate acceptor (i.e. in state 4) take up greater amounts of K(+), Na(+), choline, phosphate and Cl(-) (but less NH(4) (+)) than non-respiring control mitochondria. 2. Uptake of cations is accompanied by an increase in the volume of the mitochondrial matrix, determined with the use of [(14)C]-sucrose and (3)H(2)O. The osmolarity of the salt solution taken up was approximately that of the suspending medium. 3. The [(14)C]sucrose-inaccessible space decreased with increasing osmolarity of potassium chloride in the suspending medium, confirming that the blowfly mitochondrion behaves as an osmometer. 4. Light-scattering studies showed that both respiratory substrate and a permeant anion such as phosphate or acetate are required for rapid and massive entry of K(+), which occurs in an electrophoretic process rather than in exchange for H(+). The increase in permeability to K(+) and other cations is probably the result of a large increase in the exposed area of inner membrane surface in these mitochondria, with no intrinsic increase in the permeability per unit area. 5. No increase in permeability to K(+) and other cations occurs during phosphorylation of ADP in state 3 respiration.

  20. Mitochondria recycle nitrite back to the bioregulator nitric monoxide

    International Nuclear Information System (INIS)

    Nohl, H.; Staniek, K.; Sobhian, B.; Bahrami, S.; Redl, H.; Kozlov, A.V.

    2000-01-01

    Nitric monoxide (NO) exerts a great variety of physiological functions. L-Arginine supplies amino groups which are transformed to NO in various NO-synthase-active isoenzyme complexes. NO-synthesis is stimulated under various conditions increasing the tissue of stable NO-metabolites. The major oxidation product found is nitrite. Elevated nitrite levels were reported to exist in a variety of diseases including HIV, reperfusion injury and hypovolemic shock. Denitrifying bacteria such as Paracoccus denitrificans have a membrane bound set of cytochromes (cyt cd 1 , cyt bc) which were shown to be involved in nitrite reduction activities. Mammalian mitochondria have similar cytochromes which form part of the respiratory chain. Like in bacteria quinols are used as reductants of these types of cytochromes. The observation of one-e - divergence from this redox-couple to external dioxygen made us to study whether this site of the respiratory chain may also recycle nitrite back to its bioactive form NO. Thus, the aim of the present study was therefore to confirm the existence of a reductive pathway which reestablishes the existence of the bioregulator NO from its main metabolite NO 2 - . Our results show that respiring mitochondria readily reduce added nitrite to NO which was made visible by nitrosylation of deoxyhemoglobin. The adduct gives characteristic triplet-ESR-signals. Using inhibitors of the respiratory chain for chemical sequestration of respiratory segments we were able to identify the site where nitrite is reduced. The results confirm the ubiquinone/cyt bc 1 couple as the reductant site where nitrite is recycled. The high affinity of NO to the heme-iron of cytochrome oxidase will result in an impairment of mitochondrial energy-production. ''Nitrite tolerance'' of angina pectoris patients using NO-donors may be explained in that way. (author)

  1. Mitochondria Targeting with Luminescent Rhenium(I) Complexes.

    Science.gov (United States)

    Skiba, Joanna; Bernaś, Tytus; Trzybiński, Damian; Woźniak, Krzysztof; Ferraro, Giarita; Marasco, Daniela; Merlino, Antonello; Shafikov, Marsel Z; Czerwieniec, Rafał; Kowalski, Konrad

    2017-05-15

    Two new neutral fac -[Re(CO)₃(phen)L] compounds ( 1 , 2 ), with phen = 1,10-phenanthroline and L = O₂C(CH₂)₅CH₃ or O₂C(CH₂)₄C≡CH, were synthetized in one-pot procedures from fac -[Re(CO)₃(phen)Cl] and the corresponding carboxylic acids, and were fully characterized by IR and UV-Vis absorption spectroscopy, ¹H- and 13 C-NMR, mass spectrometry and X-ray crystallography. The compounds, which display orange luminescence, were used as probes for living cancer HeLa cell staining. Confocal microscopy revealed accumulation of both dyes in mitochondria. To investigate the mechanism of mitochondrial staining, a new non-emissive compound, fac -[Re(CO)₃(phen)L], with L = O₂C(CH₂)₃((C₅H₅)Fe(C₅H₄), i.e., containing a ferrocenyl moiety, was synthetized and characterized ( 3 ). 3 shows the same mitochondrial accumulation pattern as 1 and 2 . Emission of 3 can only be possible when ferrocene-containing ligand dissociates from the metal center to produce a species containing the luminescent fac -[Re(CO)₃(phen)]⁺ core. The release of ligands from the Re center was verified in vitro through the conjugation with model proteins. These findings suggest that the mitochondria accumulation of compounds 1 - 3 is due to the formation of luminescent fac -[Re(CO)₃(phen)]⁺ products, which react with cellular matrix molecules giving secondary products and are uptaken into the negatively charged mitochondrial membranes. Thus, reported compounds feature a rare dissociation-driven mechanism of action with great potential for biological applications.

  2. Mitochondria Targeting with Luminescent Rhenium(I Complexes

    Directory of Open Access Journals (Sweden)

    Joanna Skiba

    2017-05-01

    Full Text Available Two new neutral fac-[Re(CO3(phenL] compounds (1,2, with phen = 1,10-phenanthroline and L = O2C(CH25CH3 or O2C(CH24C≡CH, were synthetized in one-pot procedures from fac-[Re(CO3(phenCl] and the corresponding carboxylic acids, and were fully characterized by IR and UV-Vis absorption spectroscopy, 1H- and 13C-NMR, mass spectrometry and X-ray crystallography. The compounds, which display orange luminescence, were used as probes for living cancer HeLa cell staining. Confocal microscopy revealed accumulation of both dyes in mitochondria. To investigate the mechanism of mitochondrial staining, a new non-emissive compound, fac-[Re(CO3(phenL], with L = O2C(CH23((C5H5Fe(C5H4, i.e., containing a ferrocenyl moiety, was synthetized and characterized (3. 3 shows the same mitochondrial accumulation pattern as 1 and 2. Emission of 3 can only be possible when ferrocene-containing ligand dissociates from the metal center to produce a species containing the luminescent fac­[Re(CO3(phen]+ core. The release of ligands from the Re center was verified in vitro through the conjugation with model proteins. These findings suggest that the mitochondria accumulation of compounds 1–3 is due to the formation of luminescent fac-[Re(CO3(phen]+ products, which react with cellular matrix molecules giving secondary products and are uptaken into the negatively charged mitochondrial membranes. Thus, reported compounds feature a rare dissociation-driven mechanism of action with great potential for biological applications.

  3. Ca(2+-dependent regulation of the Ca(2+ concentration in the myometrium mitochondria. II. Ca(2+ effects on mitochondria membranes polarization and [Ca(2+](m

    Directory of Open Access Journals (Sweden)

    L. G. Babich

    2017-06-01

    Full Text Available It is known that Ca2+ accumulation in the mitochondria undergoes complex regulation by Ca2+ itself. But the mechanisms of such regulation are still discussed. In this paper we have shown that Ca ions directly or indirectly regulate the level of myometrium mitochondria membranes polarization. The additions of 100 µM Ca2+ were accompanied by depolarization of the mitochondria membranes. The following experiments were designed to study the impact of Ca2+ on the myometrium mitochondria [Ca2+]m. Isolated myometrium mitochondria were preincubated without or with 10 μM Са2+ followed by 100 μM Са2+ addition. Experiments were conducted in three mediums: without ATP and Mg2+ (0-medium, in the presence of 3 mM Mg2+ (Mg-medium and 3 mM Mg2+ + 3 mM ATP (Mg,ATP-medium. It was shown that the effects of 10 μM Са2+ addition were different in different mediums, namely in 0- and Mg-medium the [Ca2+]m values increased, whereas in Mg,ATP-medium statistically reliable changes were not registered. Preincubation of mitochondria with 10 μM Са2+ did not affect the [Ca2+]m value after the addition of 100 μM Са2+. The [Ca2+]m values after 100 μM Са2+ addition were the same in 0- and Mg,ATP-mediums and somewhat lower in Mg-medium. Preliminary incubation of mitochondria with 10 μM Са2+ in 0- and Mg-mediums reduced changes of Fluo 4 normalized fluorescence values that were induced by 100 μM Са2+ additions, but in Mg,ATP-medium such differences were not recorded. It is concluded that Са2+ exchange in myometrium mitochondria is regulated by the concentration of Ca ions as in the external medium, so in the matrix of mitochondria. The medium composition had a significant impact on the [Са2+]m values in the absence of exogenous cation. It is suggested that light increase of [Са2+]m before the addition of 100 μM Са2+ may have a positive effect on the functional activity of the mitochondria.

  4. Qualitative and quantitative modifications of root mitochondria during senescence of above-ground parts of Arabidopis thaliana.

    Science.gov (United States)

    Fanello, Diego Darío; Bartoli, Carlos Guillermo; Guiamet, Juan José

    2017-05-01

    This work studied modifications experienced by root mitochondria during whole plant senescence or under light deprivation, using Arabidopsis thaliana plants with YFP tagged to mitochondria. During post-bolting development, root respiratory activity started to decline after aboveground organs (i.e., rosette leaves) had senesced. This suggests that carbohydrate starvation may induce root senescence. Similarly, darkening the whole plant induced a decrease in respiration of roots. This was partially due to a decrease in the number of total mitochondria (YFP-labelled mitochondria) and most probably to a decrease in the quantity of mitochondria with a developed inner membrane potential (ΔΨm, i.e., Mitotracker red- labelled mitochondria). Also, the lower amount of mitochondria with ΔΨm compared to YFP-labelled mitochondria at 10d of whole darkened plant, suggests the presence of mitochondria in a "standby state". The experiments also suggest that small mitochondria made the main contribution to the respiratory activity that was lost during root senescence. Sugar supplementation partially restored the respiration of mitochondria after 10d of whole plant dark treatment. These results suggest that root senescence is triggered by carbohydrate starvation, with loss of ΔΨm mitochondria and changes in mitochondrial size distribution. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. MICOS and phospholipid transfer by Ups2-Mdm35 organize membrane lipid synthesis in mitochondria.

    Science.gov (United States)

    Aaltonen, Mari J; Friedman, Jonathan R; Osman, Christof; Salin, Bénédicte; di Rago, Jean-Paul; Nunnari, Jodi; Langer, Thomas; Tatsuta, Takashi

    2016-06-06

    Mitochondria exert critical functions in cellular lipid metabolism and promote the synthesis of major constituents of cellular membranes, such as phosphatidylethanolamine (PE) and phosphatidylcholine. Here, we demonstrate that the phosphatidylserine decarboxylase Psd1, located in the inner mitochondrial membrane, promotes mitochondrial PE synthesis via two pathways. First, Ups2-Mdm35 complexes (SLMO2-TRIAP1 in humans) serve as phosphatidylserine (PS)-specific lipid transfer proteins in the mitochondrial intermembrane space, allowing formation of PE by Psd1 in the inner membrane. Second, Psd1 decarboxylates PS in the outer membrane in trans, independently of PS transfer by Ups2-Mdm35. This latter pathway requires close apposition between both mitochondrial membranes and the mitochondrial contact site and cristae organizing system (MICOS). In MICOS-deficient cells, limiting PS transfer by Ups2-Mdm35 and reducing mitochondrial PE accumulation preserves mitochondrial respiration and cristae formation. These results link mitochondrial PE metabolism to MICOS, combining functions in protein and lipid homeostasis to preserve mitochondrial structure and function. © 2016 Aaltonen et al.

  6. The antineoplastic agent α-bisabolol promotes cell death by inducing pores in mitochondria and lysosomes.

    Science.gov (United States)

    Rigo, Antonella; Vinante, Fabrizio

    2016-08-01

    The sesquiterpene α-bisabolol (α-BSB) has been shown to be an effective cytotoxic agent for a variety of human cancer cells in culture and animal models. However, much of its intracellular action remains elusive. We evaluated the cytotoxic action of α-BSB against CML-T1, Jurkat and HeLa cell lines, as preclinical models for myeloid, lymphoid and epithelial neoplasias. The approach included single cell analysis (flow cytometry, immunocytology) combined with cytotoxicity and proliferation assays to characterize organelle damage, autophagy, cytostatic effect, and apoptosis. The study focuses on the relevant steps in the cytotoxic cascade triggered by α-BSB: (1) the lipid rafts through which α-BSB enters the cells, (2) the opening of pores in the mitochondria and lysosomes, (3) the activation of both caspase-dependent and caspase-independent cell death pathways, (4) the induction of autophagy and (5) apoptosis. The effectiveness of α-BSB as an agent against tumor cells is grounded on its capability to act on different layers of cell regulation to elicit different concurrent death signals, thereby neutralizing a variety of aberrant survival mechanisms leading to treatment resistance in neoplastic cell.

  7. Central Bank independence

    Directory of Open Access Journals (Sweden)

    Vasile DEDU

    2012-08-01

    Full Text Available In this paper we present the key aspects regarding central bank’s independence. Most economists consider that the factor which positively influences the efficiency of monetary policy measures is the high independence of the central bank. We determined that the National Bank of Romania (NBR has a high degree of independence. NBR has both goal and instrument independence. We also consider that the hike of NBR’s independence played an important role in the significant disinflation process, as headline inflation dropped inside the targeted band of 3% ± 1 percentage point recently.

  8. Organizing Independent Student Work

    Directory of Open Access Journals (Sweden)

    Zhadyra T. Zhumasheva

    2015-03-01

    Full Text Available This article addresses issues in organizing independent student work. The author defines the term “independence”, discusses the concepts of independent learner work and independent learner work under the guidance of an instructor, proposes a classification of assignments to be done independently, and provides methodological recommendations as to the organization of independent student work. The article discusses the need for turning the student from a passive consumer of knowledge into an active creator of it, capable of formulating a problem, analyzing the ways of solving it, coming up with an optimum outcome, and proving its correctness. The preparation of highly qualified human resources is the primary condition for boosting Kazakhstan’s competitiveness. Independent student work is a means of fostering the professional competence of future specialists. The primary form of self-education is independent work.

  9. Translocation of iron from lysosomes to mitochondria during acetaminophen-induced hepatocellular injury: Protection by starch-desferal and minocycline.

    Science.gov (United States)

    Hu, Jiangting; Kholmukhamedov, Andaleb; Lindsey, Christopher C; Beeson, Craig C; Jaeschke, Hartmut; Lemasters, John J

    2016-08-01

    , minocycline 1h after APAP decreased cell killing by half. In conclusion, release of Fe(2+) from lysosomes followed by uptake into mitochondria via MCFU occurs during APAP hepatotoxicity. Mitochondrial iron then catalyzes toxic hydroxyl radical formation, which triggers the MPT and cell killing. The efficacy of minocycline post-treatment shows minocycline as a possible therapeutic agent against APAP hepatotoxicity. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. A new hypothesis of pathogenesis based on the divorce between mitochondria and their host cells: possible relevance for Alzheimer's disease.

    Science.gov (United States)

    Agnati, L F; Guidolin, D; Baluska, F; Leo, G; Barlow, P W; Carone, C; Genedani, S

    2010-06-01

    On the basis of not only the endosymbiotic theory of eukaryotic cell organization and evolution but also of observations of transcellular communication via Tunneling NanoTubes (TNTs), the hypothesis is put forward that when mitochondria, which were once independently living prokaryote-like organisms, are subjected to detrimental genetic, toxic, or environmental conditions, including age-related endogenous factors, they can regress towards their original independent state. At that point, they can become potentially pathogenic intruders within their eukaryotic host cell. Because of the protoplasmic disequilibrium caused by an altered, or mutated, mitochondral population, certain host cells with a minimal capacity for self-renewal, such as dopaminergic neurons, risk a loss of function and degenerate. It is also proposed that altered mitochondria, as well as their mutated mtDNA, can migrate, via TNTs, into adjacent cells. In this way, neurodegenerative states are propagated between cells (glia and/or neurons) of the Central Nervous System (CNS) and that this leads to conditions such as Alzheimer's and Parkinson's disease. This proposal finds indirect support from observations on rotenone-poisoned glioblastoma cells which have been co-cultured with non-poisoned cells. Immunocytochemical techniques revealed that mitochondria, moving along the TNTs, migrated from the poisoned cells towards the healthy cells. It has also been demonstrated by means of immunocytochemistry that, in glioblastoma cell cultures, Amyloid Precursor Protein (APP) is present in TNTs, hence it may migrate from one cell to neighbouring cells. This datum may be of high relevance for a better understanding of Alzheimer's Disease (AD) since molecular, cellular, and animal model studies have revealed that the formation of amyloid beta (Abeta) and other derivatives of the APP are key pathogenic factors in AD, causing mitochondrial dysfunction, free radical generation, oxidative damage, and inflammation

  11. Role of mitochondria-associated hexokinase II in cancer cell death induced by 3-Bromopyruvate

    Science.gov (United States)

    Chen, Zhao; Zhang, Hui; Lu, Weiqin; Huang, Peng

    2009-01-01

    Summary It has long been observed that cancer cells rely more on glycolysis to generate ATP and actively use certain glycolytic metabolic intermediates for biosynthesis. Hexokinase II (HKII) is a key glycolytic enzyme that plays a role in the regulation of the mitochondria-initiated apoptotic cell death. As a potent inhibitor of hexokinase, 3-bromopyruvate (3-BrPA) is known to inhibit cancer cell energy metabolism and trigger cell death, supposedly through depletion of cellular ATP. The current study showed that 3-BrPA caused a covalent modification of HKII protein and directly triggered its dissociation from mitochondria, leading to a specific release of apoptosis-inducing factor (AIF) from the mitochondria to cytosol and eventual cell death. Co-immunoprecipitation revealed a physical interaction between HKII and AIF. Using a competitive peptide of HKII, we showed that the dissociation of hexokinase II from mitochondria alone could cause apoptotic cell death, especially in the mitochondria-deficient ρ0 cells that highly express HKII. Interestingly, the dissociation of HKII itself did no directly affect the mitochondrial membrane potential, ROS generation, and oxidative phosphorylation. Our study suggests that the physical association between HKII and AIF is important for the normal localization of AIF in the mitochondria, and disruption of this protein complex by 3-BrPA leads to their release from the mitochondria and eventual cell death. PMID:19285479

  12. Mitochondria-Associated Membranes As Networking Platforms and Regulators of Cancer Cell Fate

    Directory of Open Access Journals (Sweden)

    Maria Livia Sassano

    2017-08-01

    Full Text Available The tight cross talk between two essential organelles of the cell, the endoplasmic reticulum (ER and mitochondria, is spatially and functionally regulated by specific microdomains known as the mitochondria-associated membranes (MAMs. MAMs are hot spots of Ca2+ transfer between the ER and mitochondria, and emerging data indicate their vital role in the regulation of fundamental physiological processes, chief among them mitochondria bioenergetics, proteostasis, cell death, and autophagy. Moreover, and perhaps not surprisingly, it has become clear that signaling events regulated at the ER–mitochondria intersection regulate key processes in oncogenesis and in the response of cancer cells to therapeutics. ER–mitochondria appositions have been shown to dynamically recruit oncogenes and tumor suppressors, modulating their activity and protein complex formation, adapt the bioenergetic demand of cancer cells and to regulate cell death pathways and redox signaling in cancer cells. In this review, we discuss some emerging players of the ER–mitochondria contact sites in mammalian cells, the key processes they regulate and recent evidence highlighting the role of MAMs in shaping cell-autonomous and non-autonomous signals that regulate cancer growth.

  13. Why translation counts for mitochondria - retrograde signalling links mitochondrial protein synthesis to mitochondrial biogenesis and cell proliferation.

    Science.gov (United States)

    Battersby, Brendan J; Richter, Uwe

    2013-10-01

    Organelle biosynthesis is a key requirement for cell growth and division. The regulation of mitochondrial biosynthesis exhibits additional layers of complexity compared with that of other organelles because they contain their own genome and dedicated ribosomes. Maintaining these components requires gene expression to be coordinated between the nucleo-cytoplasmic compartment and mitochondria in order to monitor organelle homeostasis and to integrate the responses to the physiological and developmental demands of the cell. Surprisingly, the parameters that are used to monitor or count mitochondrial abundance are not known, nor are the signalling pathways. Inhibiting the translation on mito-ribosomes genetically or with antibiotics can impair cell proliferation and has been attributed to defects in aerobic energy metabolism, even though proliferating cells rely primarily on glycolysis to fuel their metabolic demands. However, a recent study indicates that mitochondrial translational stress and the rescue mechanisms that relieve this stress cause the defect in cell proliferation and occur before any impairment of oxidative phosphorylation. Therefore, the process of mitochondrial translation in itself appears to be an important checkpoint for the monitoring of mitochondrial homeostasis and might have a role in establishing mitochondrial abundance within a cell. This hypothesis article will explore the evidence supporting a role for mito-ribosomes and translation in a mitochondria-counting mechanism.

  14. Effects of Ca2+ on oxidative phosphorylation in mitochondria from the thermogenic organ of marlin.

    Science.gov (United States)

    O'Brien, J; Block, B A

    1996-12-01

    Mitochondria from the muscle-derived thermogenic (heater) organ and oxidative red muscle of the blue marlin (Makaira nigricans) were studied in order to evaluate aspects of the mechanism of thermogenesis in heater tissue. We investigated whether short-term Ca(2+)-induced uncoupling of mitochondria contributes to the thermogenic cycle of the heater organ by enhancing the respiration rate. Specific electrodes were used to obtain simultaneous measurements of oxygen consumption and Ca2+ fluxes on isolated mitochondria, and the effects of various concentrations of Ca2+ on respiration rates and the ADP phosphorylated/atomic oxygen consumed (P/O) ratio were examined. Addition of Ca2+ in excess of 10 mumol l-1 to respiring heater organ or red muscle mitochondria partially inhibited state 3 respiration and reduced the P/O ratio, indicating that the mitochondria were partially uncoupled. These effects were blocked by 2 mumol l-1 Ruthenium Red. In heater organ mitochondria, state 3 respiration rate and the P/O ratio were not significantly reduced by 1 mumol l-1 free Ca2+, a concentration likely to be near the maximum achieved in a stimulated cell. This indicates that transient increases in cytosolic Ca2+ concentration may not significantly reduce the P/O ratio of heater organ mitochondria. The activity of 2-oxoglutarate dehydrogenase in heater organ mitochondria was stimulated by approximately 15% by Ca2+ concentrations between 0.2 and 1 mumol l-1. These results suggest that heater organ mitochondria are able to maintain a normal P/O ratio and should maintain ATP output during transient increases in Ca2+ concentration, supporting a model in which an ATP-consuming process drives thermogenesis. Activation of mitochondrial dehydrogenases by low levels of Ca2+ may also enhance respiration and contribute to thermogenesis.

  15. Melatonin as a mitochondria-targeted antioxidant: one of evolution's best ideas.

    Science.gov (United States)

    Reiter, Russel J; Rosales-Corral, Sergio; Tan, Dun Xian; Jou, Mei Jie; Galano, Annia; Xu, Bing

    2017-11-01

    Melatonin is an ancient antioxidant. After its initial development in bacteria, it has been retained throughout evolution such that it may be or may have been present in every species that have existed. Even though it has been maintained throughout evolution during the diversification of species, melatonin's chemical structure has never changed; thus, the melatonin present in currently living humans is identical to that present in cyanobacteria that have existed on Earth for billions of years. Melatonin in the systemic circulation of mammals quickly disappears from the blood presumably due to its uptake by cells, particularly when they are under high oxidative stress conditions. The measurement of the subcellular distribution of melatonin has shown that the concentration of this indole in the mitochondria greatly exceeds that in the blood. Melatonin presumably enters mitochondria through oligopeptide transporters, PEPT1, and PEPT2. Thus, melatonin is specifically targeted to the mitochondria where it seems to function as an apex antioxidant. In addition to being taken up from the circulation, melatonin may be produced in the mitochondria as well. During evolution, mitochondria likely originated when melatonin-forming bacteria were engulfed as food by ancestral prokaryotes. Over time, engulfed bacteria evolved into mitochondria; this is known as the endosymbiotic theory of the origin of mitochondria. When they did so, the mitochondria retained the ability to synthesize melatonin. Thus, melatonin is not only taken up by mitochondria but these organelles, in addition to many other functions, also probably produce melatonin as well. Melatonin's high concentrations and multiple actions as an antioxidant provide potent antioxidant protection to these organelles which are exposed to abundant free radicals.

  16. EFFECT OF ACTIVE ACCUMULATION OF CALCIUM AND PHOSPHATE IONS ON THE STRUCTURE OF RAT LIVER MITOCHONDRIA

    Science.gov (United States)

    Greenawalt, John W.; Rossi, Carlo S.; Lehninger, Albert L.

    1964-01-01

    Rat liver mitochondria allowed to accumulate maximal amounts of Ca++ and HPO4 = ions from the suspending medium in vitro during respiration have a considerably higher specific gravity than normal mitochondria and may be easily separated from the latter by isopycnic centrifugation in density gradients of sucrose or cesium chloride. When the mitochondria are allowed to accumulate less than maximal amounts of Ca++ and HPO4 = from the medium, they have intermediate specific gravities which are roughly proportional to their content of calcium phosphate. Maximally "loaded" mitochondria are relatively homogeneous with respect to specific gravity. Correlated biochemical and electron microscopic studies show that Ca++-loaded mitochondria contain numerous dense granules, of which some 85 per cent are over 500 A in diameter. These granules are electron-opaque not only following fixation and staining with heavy metal reagents, but also following fixation with formaldehyde, demonstrating that the characteristic granules in Ca++-loaded mitochondria have intrinsic electron-opacity. The dense granules are almost always located within the inner compartment of the mitochondria and not in the space between the inner and outer membranes. They are frequently located at or near the cristae and they often show electron-transparent "cores." Such granules appear to be made up of clusters of smaller dense particles, but preliminary x-ray diffraction analysis and electron diffraction studies have revealed no evidence of crystallinity in the deposits. The electron-opaque granules decrease in number when the Ca++-loaded mitochondria are incubated with 2,4-dinitrophenol; simultaneously there is discharge of Ca++ and phosphate from the mitochondria into the medium. PMID:14228516

  17. Structure of cells chloroplasts and mitochondria of cotton leaves following gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Arslanova, S V [AN Uzbekskoj SSR, Tashkent. Inst. Ehksperimental' noj Biologii Rastenij

    1975-01-01

    The article investigates the structural changes in the plastides and mitochondria of cotton leaf cells after irradiation. Cotton seeds that had been moistened for 24 hours were irradiated by a gamma source with a dose of 10 kR (intensity: 19 R/s.). For the study of the plastides and mitochondria of the leaf cells samples were taken in the cotyledonous leaf and flowering phases of the cotton. The cells of the cotton leaf mesophillum in the standard consists of chloroplast with developed interior structures. Study of the ultrastructure of the cells of the mesophilic tissue of the cotyledonous leaf in irradiated cotton plants showed that the chloroplastide membranes are not damaged. A change in the form of the chloroplasts, an accumulation of starch and plastic substances in the chloroplasts, and a reduction in the number of inter-grain bonds were noted. It was discovered that gamma irradiation produces an excessive build-up of starch in the chloroplasts. The mitochondria are often located close to the plastides. The optical density is typical of the matrix of the mitochondria in non-irradiated plants. After cotton seeds that have sprouted are irradiated with a dose of 10 kR in the cotyledonous leaf phase, part of the mitochondria swells. The matrix becomes more transparent, and the number of chrysts decreases. Part of the mitochondria remains intact. The optical density and internal membranes of the mitochondria remain the same as in the control group. The disturbances of the chloroplast and the mitochondria are also observed in the budding and flowering phases (under conditions of a natural day). It was noted that a shortened day facilitated to some extent a normalization of metabolism, and this produced in turn a normal development of the chloroplasts, leaf mitochondria and ATF generation, which reduces the final biological effect of the radiation.

  18. Polyamine conjugation of curcumin analogues toward the discovery of mitochondria-directed neuroprotective agents.

    Science.gov (United States)

    Simoni, Elena; Bergamini, Christian; Fato, Romana; Tarozzi, Andrea; Bains, Sandip; Motterlini, Roberto; Cavalli, Andrea; Bolognesi, Maria Laura; Minarini, Anna; Hrelia, Patrizia; Lenaz, Giorgio; Rosini, Michela; Melchiorre, Carlo

    2010-10-14

    Mitochondria-directed antioxidants 2-5 were designed by conjugating curcumin congeners with different polyamine motifs as vehicle tools. The conjugates emerged as efficient antioxidants in mitochondria and fibroblasts and also exerted a protecting role through heme oxygenase-1 activation. Notably, the insertion of a polyamine function into the curcumin-like moiety allowed an efficient intracellular uptake and mitochondria targeting. It also resulted in a significant decrease in the cytotoxicity effects. 2-5 are therefore promising molecules for neuroprotectant lead discovery.

  19. Raman probing of lipids, proteins, and mitochondria in skeletal myocytes: a case study on obesity

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A.; Nikelshparg, Evelina I.; Prats, Clara

    2017-01-01

    We propose a novel approach to assess simultaneously lipid composition in lipid droplets, the redox state of cytochromes, and the relative amount of [Fe–S] clusters in the electron transport chain in the mitochondria of skeletal myocytes by means of near-infrared Raman spectroscopy. Mitochondria...... technique allows to estimate qualitatively the relative amount of cholesterol and unsaturated lipids, ordering of lipid phase in lipid droplets, changes in the redox state of c-type and b-type cytochromes, and the relative amount of [Fe–S] clusters in the mitochondria of intact myocytes. The proposed...

  20. Gamma radiation effect on the mitochondria ultrastructure in different radiosensitive types of cotton plants

    Energy Technology Data Exchange (ETDEWEB)

    Arslanov, S V

    1973-01-01

    When germinated seeds are irradiated with a dose of 10 krad, the mitochondrial ultrastructure is disrupted in the early-ripening 1306-DV and the late-ripening S-1622 varieties of the cotton-plant. The mitochondria exhibited swelling, breakdown of internal structure and vacuolation. In the S-1622 variety the mitochondria shrink owing to their small number and larger size and to the smaller number of cristae. Changes in the ultrafine organization of mitochondria lead to inhibition of carbohydrate oxidation through the Krebs cycle and intensification of oxidation through the pentosophosphate cycle.

  1. Mitochondrial Ca2+ influx and efflux rates in guinea pig cardiac mitochondria: low and high affinity effects of cyclosporine A.

    Science.gov (United States)

    Wei, An-Chi; Liu, Ting; Cortassa, Sonia; Winslow, Raimond L; O'Rourke, Brian

    2011-07-01

    Ca(2+) plays a central role in energy supply and demand matching in cardiomyocytes by transmitting changes in excitation-contraction coupling to mitochondrial oxidative phosphorylation. Matrix Ca(2+) is controlled primarily by the mitochondrial Ca(2+) uniporter and the mitochondrial Na(+)/Ca(2+) exchanger, influencing NADH production through Ca(2+)-sensitive dehydrogenases in the Krebs cycle. In addition to the well-accepted role of the Ca(2+)-triggered mitochondrial permeability transition pore in cell death, it has been proposed that the permeability transition pore might also contribute to physiological mitochondrial Ca(2+) release. Here we selectively measure Ca(2+) influx rate through the mitochondrial Ca(2+) uniporter and Ca(2+) efflux rates through Na(+)-dependent and Na(+)-independent pathways in isolated guinea pig heart mitochondria in the presence or absence of inhibitors of mitochondrial Na(+)/Ca(2+) exchanger (CGP 37157) or the permeability transition pore (cyclosporine A). cyclosporine A suppressed the negative bioenergetic consequences (ΔΨ(m) loss, Ca(2+) release, NADH oxidation, swelling) of high extramitochondrial Ca(2+) additions, allowing mitochondria to tolerate total mitochondrial Ca(2+) loads of >400nmol/mg protein. For Ca(2+) pulses up to 15μM, Na(+)-independent Ca(2+) efflux through the permeability transition pore accounted for ~5% of the total Ca(2+) efflux rate compared to that mediated by the mitochondrial Na(+)/Ca(2+) exchanger (in 5mM Na(+)). Unexpectedly, we also observed that cyclosporine A inhibited mitochondrial Na(+)/Ca(2+) exchanger-mediated Ca(2+) efflux at higher concentrations (IC(50)=2μM) than those required to inhibit the permeability transition pore, with a maximal inhibition of ~40% at 10μM cyclosporine A, while having no effect on the mitochondrial Ca(2+) uniporter. The results suggest a possible alternative mechanism by which cyclosporine A could affect mitochondrial Ca(2+) load in cardiomyocytes, potentially

  2. A complex effect of arsenite on the formation of alpha-ketoglutarate in rat liver mitochondria.

    Science.gov (United States)

    Lenartowicz, E

    1990-12-01

    This investigation presents disturbances of the mitochondrial metabolism by arsenite, a hydrophilic dithiol reagent known as an inhibitor of mitochondrial alpha-keto acid dehydrogenases. Arsenite at concentrations of 0.1-1.0 mM was shown to induce a considerable oxidation of intramitochondrial NADPH, NADH, and glutathione without decreasing the mitochondrial membrane potential. The oxidation of NAD(P)H required the presence of phosphate and was sensitive to ruthenium red, but occurred without the addition of calcium salts. Mitochondrial reactions producing alpha-ketoglutarate from glutamate and isocitrate were modulated by arsenite through various mechanisms: (i) both glutamate transaminations, with oxaloacetate and with pyruvate, were inhibited by accumulating alpha-ketoglutarate; however, at low concentrations of alpha-ketoglutarate the aspartate aminotransferase reaction was stimulated due to the increase of NAD+ content; (ii) the oxidation of isocitrate was stimulated at its low concentration only, due to the oxidation of NADPH and NADH; this oxidation was prevented by concentrations of citrate or isocitrate greater than 1 mM; (iii) the conversion of isocitrate to citrate was suppressed, presumably as a result of the decrease of Mg2+ concentration in mitochondria. Thus the depletion of mitochondrial vicinal thiol groups in hydrophilic domains disturbs the mitochondrial metabolism not only by the inhibition of alpha-keto acid dehydrogenases but also by the oxidation of NAD(P)H and, possibly, by the change in the ion concentrations.

  3. DNA copy number, including telomeres and mitochondria, assayed using next-generation sequencing

    Directory of Open Access Journals (Sweden)

    Jackson Stuart

    2010-04-01

    Full Text Available Abstract Background DNA copy number variations occur within populations and aberrations can cause disease. We sought to develop an improved lab-automatable, cost-efficient, accurate platform to profile DNA copy number. Results We developed a sequencing-based assay of nuclear, mitochondrial, and telomeric DNA copy number that draws on the unbiased nature of next-generation sequencing and incorporates techniques developed for RNA expression profiling. To demonstrate this platform, we assayed UMC-11 cells using 5 million 33 nt reads and found tremendous copy number variation, including regions of single and homogeneous deletions and amplifications to 29 copies; 5 times more mitochondria and 4 times less telomeric sequence than a pool of non-diseased, blood-derived DNA; and that UMC-11 was derived from a male individual. Conclusion The described assay outputs absolute copy number, outputs an error estimate (p-value, and is more accurate than array-based platforms at high copy number. The platform enables profiling of mitochondrial levels and telomeric length. The assay is lab-automatable and has a genomic resolution and cost that are tunable based on the number of sequence reads.

  4. Effect of cadmium on electron and energy transfer reactions in corn mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R J; Bittell, J E; Koeppe, D E

    1973-01-01

    The effects of cadmium on isolated corn shoot mitochondria were determined. In the absence of phosphate cadmium stimulated the oxidation of exogenous NADH optimally at 0.025 mM, but was inhibitory at 0.1 mM and above. The presence of phosphate negated the cadmium stimulation of exogenous NADH oxidation and permitted inhibitions only at higher cadmium concentrations. Succinate or malate + pyruvate oxidation in the absence of phosphate was inhibited to a greater extent by cadmium than when phosphate was present. ADP/O and respiratory control ratios were reduced by cadmium but generally were less sensitive to cadmium than state 4 or minus phosphate respiration. The data suggest that the site of cadmium effect is likely to be early in electron transport. Cadmium had a pronounced effect on mitochondrial swelling under either passive or active conditions. When succinate or exogenous NADH were being oxidized swelling occurred at 0.05 mM cadmium, but with malate + pyruvate the cadmium concentration had to exceed 1.0 mM. Phosphate (2 mM) prevented the swelling. Dithiothreitol, a SH group protector, prevented any effect of cadmium on swelling or respiration which suggests that sulfhydryl groups are likely involved in the cadmium-membrane interaction.

  5. Brain mitochondria as a primary target in the development of treatment strategies for Alzheimer disease.

    Science.gov (United States)

    Aliev, Gjumrakch; Palacios, Hector H; Walrafen, Brianna; Lipsitt, Amanda E; Obrenovich, Mark E; Morales, Ludis

    2009-10-01

    Alzheimer's disease (AD) and cerebrovascular accidents are two leading causes of age-related dementia. Increasing evidence supports the idea that chronic hypoperfusion is primarily responsible for the pathogenesis that underlies both disease processes. In this regard, hypoperfusion appears to induce oxidative stress (OS), which is largely due to reactive oxygen species (ROS), and over time initiates mitochondrial failure which is known as an initiating factor of AD. Recent evidence indicates that chronic injury stimulus induces hypoperfusion seen in vulnerable brain regions. This reduced regional cerebral blood flow (CBF) then leads to energy failure within the vascular endothelium and associated brain parenchyma, manifested by damaged mitochondrial ultrastructure (the formation of large number of immature, electron-dense "hypoxic" mitochondria) and by overproduction of mitochondrial DNA (mtDNA) deletions. Additionally, these mitochondrial abnormalities co-exist with increased redox metal activity, lipid peroxidation, and RNA oxidation. Interestingly, vulnerable neurons and glial cells show mtDNA deletions and oxidative stress markers only in the regions that are closely associated with damaged vessels, and, moreover, brain vascular wall lesions linearly correlate with the degree of neuronal and glial cell damage. We summarize the large body of evidence which indicates that sporadic, late-onset AD results from a vascular etiology by briefly reviewing mitochondrial damage and vascular risk factors associated with the disease and then we discuss the cerebral microvascular changes reason for the energy failure that occurs in normal aging and, to a much greater extent, AD.

  6. Ion transport by mitochondria-rich cells in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Ussing, H H; Spring, K R

    1987-01-01

    The optical sectioning video imaging technique was used for measurements of the volume of mitochondria-rich (m.r.) cells of the isolated epithelium of toad skin. Under short-circuit conditions, cell volume decreased by about 14% in response to bilateral exposure to Cl-free (gluconate substitution....... Unilateral exposure to a Cl-free solution did not prevent ouabain-induced cell swelling. It is concluded that m.r. cells have an amiloride-blockable Na conductance in the apical membrane, a ouabain-sensitive Na pump in the basolateral membrane, and a passive Cl permeability in both membranes. From...... the initial rate of ouabain-induced cell volume increase the active Na current carried by a single m.r. cell was estimated to be 9.9 +/- 1.3 pA. Voltage clamping of the preparation in the physiological range of potentials (0 to -100 mV, serosa grounded) resulted in a cell volume increase with a time course...

  7. Branchial mitochondria-rich cells in the dogfish Squalus acanthias.

    Science.gov (United States)

    Wilson, Jonathan M; Morgan, John D; Vogl, A Wayne; Randall, David J

    2002-06-01

    In marine teleost fishes, the gill mitochondria-rich cells (MRCs) are responsible for NaCl elimination; however, in elasmobranch fishes, the specialized rectal gland is considered to be the most important site for salt secretion. The role of the gills in elasmobranch ion regulation, although clearly shown to be secondary, is not well characterized. In the present study, we investigated some morphological properties of the branchial MRCs and the localization, and activity of the important ionoregulatory enzyme Na(+)/K(+)-ATPase, under control conditions and following rectal gland removal (1 month) in the spiny dogfish, Squalus acanthias. A clear correlation can be made between MRC numbers and the levels of Na(+)/K(+)-ATPase activity in crude gill homogenates (r(2)=-0.69). Strong Na(+)/K(+)-ATPase immunoreactivity is also clearly associated with the basolateral membrane of these MRCs. In addition, the dogfish were able to maintain ionic balance after rectal gland removal. These results all suggest a possible role of the dogfish gill in salt secretion. MRCs were, however, unresponsive to rectal gland removal in terms of changes in number, fine structure and Na(+)/K(+)-ATPase activity, as might be expected if they were compensating for the loss of salt secretion by the rectal gland. Thus, the specific role that these MRCs play in ion regulation in the dogfish remains to be determined

  8. Homeostasis of the protonmotive force in phosphorylating mitochondria.

    Science.gov (United States)

    Duszyński, J; Bogucka, K; Wojtczak, L

    1984-12-18

    The relationship between the respiration rate and the magnitude of the electrochemical proton potential (delta mu H+) in rat liver mitochondria was investigated. (1) Under the active-state conditions, the action of inhibitors of either phosphorylation (oligomycin) or respiration (rotenone, malonate) on the respiration and delta mu H+ was measured. Both inhibitors diminished the respiration, whereas rotenone resulted in a decrease of delta mu H+, and oligomycin produced an increase of this potential. The effect of the inhibitors was much more pronounced on the respiration rate than on delta mu H+; for example, the excess of oligomycin produced a 90% inhibition of the respiration while delta mu H+ was changed only by 9%. (2) Under the resting-state conditions, small concentrations of the uncoupler stimulated the respiration while changing delta mu H+ to a relatively small extent. The uncoupler concentrations which doubled and tripled the respiration rate produced only 5 and 9% decrease of delta mu H+, respectively. (3) The present results enabled us to propose a model describing the interrelationship between respiration and delta mu H+.

  9. The role of mitochondria for the regulation of cardiac alternans

    Directory of Open Access Journals (Sweden)

    Stela M Florea

    2010-11-01

    Full Text Available Electromechanical and Ca alternans is a beat-to-beat alternation of action potential duration, contraction strength and Ca transient amplitude observed in cardiac myocytes at regular stimulation frequency. Ca alternans is a multifactorial process that is causally linked to cardiac arrhythmias. At the cellular level, conditions that increase fractional release from the sarcoplasmic reticulum or reduce diastolic Ca sequestration favor the occurrence of alternans. Mitochondria play a significant role in cardiac excitation-contraction coupling and Ca signaling by providing the energy for contraction and ATP-dependent processes and possibly by serving as Ca buffering organelles. Here we tested the hypothesis that impairment of mitochondrial function generates conditions that favor the occurrence of Ca alternans. Alternans were elicited by electrical pacing (>1 Hz in single cat atrial myocytes and intracellular Ca ([Ca]i was measured with the fluorescent Ca indicator Indo-1. The degree of alternans was quantified as the alternans ratio (AR=1-S/L, where S/L is the ratio of the small to the large amplitude of a pair of alternating Ca transients. Dissipation of mitochondrial membrane potential (with FCCP as well as inhibition of mitochondrial F1/F0-ATP synthase (oligomycin, electrontransport chain (rotenone, antimycin, CN-, Ca-dependent dehydrogenases and mitochondrial Ca uptake or extrusion, all enhanced AR and lowered the threshold for the occurrence of Ca alternans. The data indicate that impairment of mitochondrial function adversely affects cardiac Ca cycling leading to proarrhythmic Ca alternans.

  10. Strigolactones Stimulate Arbuscular Mycorrhizal Fungi by Activating Mitochondria

    Science.gov (United States)

    Besserer, Arnaud; Puech-Pagès, Virginie; Kiefer, Patrick; Gomez-Roldan, Victoria; Jauneau, Alain; Roy, Sébastien; Portais, Jean-Charles; Roux, Christophe; Bécard, Guillaume

    2006-01-01

    The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10 −13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants. PMID:16787107

  11. Strigolactones stimulate arbuscular mycorrhizal fungi by activating mitochondria.

    Directory of Open Access Journals (Sweden)

    Arnaud Besserer

    2006-07-01

    Full Text Available The association of arbuscular mycorrhizal (AM fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10(-13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants.

  12. Are Synonymous Substitutions in Flowering Plant Mitochondria Neutral?

    Science.gov (United States)

    Wynn, Emily L; Christensen, Alan C

    2015-10-01

    Angiosperm mitochondrial genes appear to have very low mutation rates, while non-gene regions expand, diverge, and rearrange quickly. One possible explanation for this disparity is that synonymous substitutions in plant mitochondrial genes are not truly neutral and selection keeps their occurrence low. If this were true, the explanation for the disparity in mutation rates in genes and non-genes needs to consider selection as well as mechanisms of DNA repair. Rps14 is co-transcribed with cob and rpl5 in most plant mitochondrial genomes, but in some genomes, rps14 has been duplicated to the nucleus leaving a pseudogene in the mitochondria. This provides an opportunity to compare neutral substitution rates in pseudogenes with synonymous substitution rates in the orthologs. Genes and pseudogenes of rps14 have been aligned among different species and the mutation rates have been calculated. Neutral substitution rates in pseudogenes and synonymous substitution rates in genes are significantly different, providing evidence that synonymous substitutions in plant mitochondrial genes are not completely neutral. The non-neutrality is not sufficient to completely explain the exceptionally low mutation rates in land plant mitochondrial genomes, but selective forces appear to play a small role.

  13. Respiratory analysis of coupled mitochondria in cryopreserved liver biopsies

    Directory of Open Access Journals (Sweden)

    Mercedes García-Roche

    2018-07-01

    Full Text Available The aim of this work was to develop a cryopreservation method of small liver biopsies for in situ mitochondrial function assessment. Herein we describe a detailed protocol for tissue collection, cryopreservation, high-resolution respirometry using complex I and II substrates, calculation and interpretation of respiratory parameters. Liver biopsies from cow and rat were sequentially frozen in a medium containing dimethylsulfoxide as cryoprotectant and stored for up to 3 months at −80 °C. Oxygen consumption rate studies of fresh and cryopreserved samples revealed that most respiratory parameters remained unchanged. Additionally, outer mitochondrial membrane integrity was assessed adding cytochrome c, proving that our cryopreservation method does not harm mitochondrial structure. In sum, we present a reliable way to cryopreserve small liver biopsies without affecting mitochondrial function. Our protocol will enable the transport and storage of samples, extending and facilitating mitochondrial function analysis of liver biopsies. Keywords: Cryopreservation, Mitochondria, Biopsy, Oxygen consumption rate, High-resolution respirometry, Mitochondrial function

  14. Accounting for Independent Schools.

    Science.gov (United States)

    Sonenstein, Burton

    The diversity of independent schools in size, function, and mode of operation has resulted in a considerable variety of accounting principles and practices. This lack of uniformity has tended to make understanding, evaluation, and comparison of independent schools' financial statements a difficult and sometimes impossible task. This manual has…

  15. The effect of alpha-tocopheryl succinate on succinate respiration in rat liver mitochondria

    Czech Academy of Sciences Publication Activity Database

    Sobotka, O.; Drahota, Zdeněk; Kučera, O.; Endlicher, R.; Rauchová, Hana; Červinková, Z.

    2015-01-01

    Roč. 64, Suppl.5 (2015), S609-S615 ISSN 0862-8408 Institutional support: RVO:67985823 Keywords : tocopheryl succinate * Complex II * liver * mitochondria * homogenate * hepatocytes Subject RIV: ED - Physiology Impact factor: 1.643, year: 2015

  16. PEGylated anticancer-carbon nanotubes complex targeting mitochondria of lung cancer cells

    Science.gov (United States)

    Kim, Sang-Woo; Lee, Yeon Kyung; Lee, Jong Yeon; Hong, Jeong Hee; Khang, Dongwoo

    2017-11-01

    Although activating apoptosis in cancer cells by targeting the mitochondria is an effective strategy for cancer therapy, insufficient targeting of the mitochondria in cancer cells restricts the availability in clinical treatment. Here, we report on a polyethylene glycol-coated carbon nanotube (CNT)-ABT737 nanodrug that improves the mitochondrial targeting of lung cancer cells. The polyethylene glycol-coated CNT-ABT737 nanodrug internalized into the early endosomes via macropinocytosis and clathrin-mediated endocytosis in advance of early endosomal escape and delivered into the mitochondria. Cytosol release of the nanodrug led to apoptosis of lung cancer cells by abruption of the mitochondrial membrane potential, inducing Bcl-2-mediated apoptosis and generating intracellular reactive oxygen species. As such, this study provides an effective strategy for increasing the anti-lung cancer efficacy by increasing mitochondria accumulation rate of cytosol released anticancer nanodrugs.

  17. Inherited complex I deficiency is associated with faster protein diffusion in the matrix of moving mitochondria

    NARCIS (Netherlands)

    Koopman, W.J.H.; Distelmaier, F.; Hink, M.A.; Verkaart, S.; Wijers, M.; Fransen, J.; Smeitink, J.A.M.; Willems, P.H.G.M.

    2008-01-01

    Mitochondria continuously change shape, position, and matrix configuration for optimal metabolite exchange. It is well established that changes in mitochondrial metabolism influence mitochondrial shape and matrix configuration. We demonstrated previously that inhibition of mitochondrial complex I

  18. Ultrastructural and functional abnormalities of mitochondria in cultivated fibroblasts from α -mannosidosis patiens

    Czech Academy of Sciences Publication Activity Database

    Brantová, O.; Asfaw, B.; Sládková, J.; Poupětová, H.; Živný, J.; Magner, M.; Krůšek, Jan; Veselá, K.; Hansíková, H.; Ledvinová, J.; Tesařová, M.; Zeman, J.

    2009-01-01

    Roč. 64, č. 2 (2009), s. 394-401 ISSN 0006-3088 Institutional research plan: CEZ:AV0Z50110509 Keywords : mitochondria * endoplasmatic reticulum * ultrastructure Subject RIV: ED - Physiology Impact factor: 0.617, year: 2009

  19. THE ROLE OF MITOCHONDRIA IN THE DEVELOPMENT AND PROGRESSION OF LUNG CANCER

    Directory of Open Access Journals (Sweden)

    Emily R Roberts

    2013-03-01

    Mitochondrial dysfunction in cancer has expanded to include defects in mitochondrial genomics and biogenesis, apoptotic signaling and mitochondrial dynamics. This review will focus on the role of mitochondria and their influence on cancer initiation, progression and treatment in the lung.

  20. Thioredoxin-2 (TRX-2) is an essential gene regulating mitochondria-dependent apoptosis.

    Science.gov (United States)

    Tanaka, Toru; Hosoi, Fumihito; Yamaguchi-Iwai, Yuko; Nakamura, Hajime; Masutani, Hiroshi; Ueda, Shugo; Nishiyama, Akira; Takeda, Shunichi; Wada, Hiromi; Spyrou, Giannis; Yodoi, Junji

    2002-04-02

    Thioredoxin-2 (Trx-2) is a mitochondria-specific member of the thioredoxin superfamily. Mitochondria have a crucial role in the signal transduction for apoptosis. To investigate the biological significance of Trx-2, we cloned chicken TRX-2 cDNA and generated clones of the conditional Trx-2-deficient cells using chicken B-cell line, DT40. Here we show that TRX-2 is an essential gene and that Trx-2-deficient cells undergo apoptosis upon repression of the TRX-2 transgene, showing an accumulation of intracellular reactive oxygen species (ROS). Cytochrome c is released from mitochondria, while caspase-9 and caspase-3, but not caspase-8, are activated upon inhibition of the TRX-2 transgene. In addition, Trx-2 and cytochrome c are co-immunoprecipitated in an in vitro assay. These results suggest that mitochondrial Trx-2 is essential for cell viability, playing a crucial role in the scavenging ROS in mitochondria and regulating the mitochondrial apoptosis signaling pathway.

  1. Xanthurenic acid translocates proapoptotic Bcl-2 family proteins into mitochondria and impairs mitochondrial function

    Directory of Open Access Journals (Sweden)

    Hess Otto M

    2004-04-01

    Full Text Available Abstract Background Xanthurenic acid is an endogenous molecule produced by tryptophan degradation, produced in the cytoplasm and mitochondria. Its accumulation can be observed in aging-related diseases, e.g. senile cataract and infectious disease. We previously reported that xanthurenic acid provokes apoptosis, and now present a study of the response of mitochondria to xanthurenic acid. Results Xanthurenic acid at 10 or 20 μM in culture media of human aortic smooth muscle cells induces translocation of the proteins Bax, Bak, Bclxs, and Bad into mitochondria. In 20 μM xanthurenic acid, Bax is also translocated to the nucleus. In isolated mitochondria xanthurenic acid leads to Bax and Bclxs oligomerization, accumulation of Ca2+, and increased oxygen consumption. Conclusion Xanthurenic acid interacts directly with Bcl-2 family proteins, inducing mitochondrial pathways of apoptosis and impairing mitochondrial functions.

  2. Temperature controls oxidative phosphorylation and reactive oxygen species production through uncoupling in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Jarmuszkiewicz, Wieslawa; Woyda-Ploszczyca, Andrzej; Koziel, Agnieszka; Majerczak, Joanna; Zoladz, Jerzy A

    2015-06-01

    Mitochondrial respiratory and phosphorylation activities, mitochondrial uncoupling, and hydrogen peroxide formation were studied in isolated rat skeletal muscle mitochondria during experimentally induced hypothermia (25 °C) and hyperthermia (42 °C) compared to the physiological temperature of resting muscle (35 °C). For nonphosphorylating mitochondria, increasing the temperature from 25 to 42 °C led to a decrease in membrane potential, hydrogen peroxide production, and quinone reduction levels. For phosphorylating mitochondria, no temperature-dependent changes in these mitochondrial functions were observed. However, the efficiency of oxidative phosphorylation decreased, whereas the oxidation and phosphorylation rates and oxidative capacities of the mitochondria increased, with increasing assay temperature. An increase in proton leak, including uncoupling protein-mediated proton leak, was observed with increasing assay temperature, which could explain the reduced oxidative phosphorylation efficiency and reactive oxygen species production. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. A Novel Mitochondria-Dependent Apoptotic Pathway (MAP) in Prostate Cancer (Pca) Cells

    National Research Council Canada - National Science Library

    Chandra, Dhyan

    2004-01-01

    ...) are also up-regulated (Chandra et al., J. Biol. Chem., 277, 50842-54; 2002). Later, when the apoptotic machinery is activated, I notice that there is prominent localization of active caspase-9 and -3 in the mitochondria...

  4. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients

    Directory of Open Access Journals (Sweden)

    Adler Charles

    2009-07-01

    Full Text Available Abstract Correction to Nural H, He P, Beach T, Sue L, Xia W, Shen Y. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients Molecular Neurodegeneration 2009, 4:23.

  5. Two-Photon Probes for Lysosomes and Mitochondria: Simultaneous Detection of Lysosomes and Mitochondria in Live Tissues by Dual-Color Two-Photon Microscopy Imaging.

    Science.gov (United States)

    Lim, Chang Su; Hong, Seung Taek; Ryu, Seong Shick; Kang, Dong Eun; Cho, Bong Rae

    2015-10-01

    Novel two-photon (TP) probes were developed for lysosomes (PLT-yellow) and mitochondria (BMT-blue and PMT-yellow). These probes emitted strong TP-excited fluorescence in cells at widely separated wavelength regions and displayed high organelle selectivity, good cell permeability, low cytotoxicity, and pH insensitivity. The BMT-blue and PLT-yellow probes could be utilized to detect lysosomes and mitochondria simultaneously in live tissues by using dual-color two-photon microscopy, with minimum interference from each other. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Edaravone Decreases Paraquat Toxicity in A549 Cells and Lung Isolated Mitochondria

    OpenAIRE

    Shokrzadeh, Mohammad; Shaki, Fatemeh; Mohammadi, Ebrahim; Rezagholizadeh, Neda; Ebrahimi, Fatemeh

    2014-01-01

    Edaravone, an antioxidant and radical scavenger, showed protective effects against oxidative stress-like condition. Paraquat (PQ) is toxic herbicide considerable evidence suggests that oxidative stress and mitochondrial dysfunction contribute to PQ toxicity. In this study, protective effect of edaravone against PQ induced toxicity and reactive oxygen species (ROS) generation in A549 cells and lung isolated mitochondria were evaluated. A549 cells and lung isolated mitochondria were divided int...

  7. A Powerful Mitochondria-Targeted Iron Chelator Affords High Photoprotection against Solar Ultraviolet A Radiation

    OpenAIRE

    Reelfs, Olivier; Abbate, Vincenzo; Hider, Robert C.; Pourzand, Charareh

    2016-01-01

    Mitochondria are the principal destination for labile iron, making these organelles particularly susceptible to oxidative damage on exposure to ultraviolet A (UVA, 320?400 nm), the oxidizing component of sunlight. The labile iron-mediated oxidative damage caused by UVA to mitochondria leads to necrotic cell death via adenosine triphosphate depletion. Therefore, targeted removal of mitochondrial labile iron via highly specific tools from these organelles may be an effective approach to protect...

  8. Radioprotective effects of Asparagus racemosus extracts against free radical damage in rat liver mitochondria

    International Nuclear Information System (INIS)

    Boloor, K.K.; Kamat, J.P.; Devasagayam, T.P.A.; Venkatachalam, S.R.

    2000-01-01

    The possible antioxidant effect of the extracts of Asparagus racemosus against membrane damage induced by free radicals generated during γ-radiation was examined in rat liver/brain mitochondria. These extracts displayed significant antioxidant properties in mitochondria against oxidation of both lipids and proteins as assessed by lipid peroxidation, protein oxidation and depletion of thiols. The inhibitory effect of the extracts, rich in polysaccharides like galactose, was more than that of the established antioxidants glutathione and ascorbic acid. (author)

  9. “Pulling the plug” on cellular copper: The role of mitochondria in copper export

    OpenAIRE

    Leary, Scot C.; Winge, Dennis R.; Cobine, Paul A.

    2008-01-01

    Mitochondria contain two enzymes, Cu, Zn superoxide dismutase (Sod1) and cytochrome c oxidase (CcO), that require copper as a cofactor for their biological activity. The copper used for their metallation originates from a conserved, bioactive pool contained within the mitochondrial matrix, the size of which changes in response to either genetic or pharmacological manipulation of cellular copper status. Its dynamic nature implies molecular mechanisms exist that functionally couple mitochondria...

  10. Mitochondria from rat uterine smooth muscle possess ATP-sensitive potassium channel

    Directory of Open Access Journals (Sweden)

    Olga B. Vadzyuk

    2018-03-01

    Full Text Available The objective of this study was to detect ATP-sensitive K+ uptake in rat uterine smooth muscle mitochondria and to determine possible effects of its activation on mitochondrial physiology. By means of fluorescent technique with usage of K+-sensitive fluorescent probe PBFI (potassium-binding benzofuran isophthalate we showed that accumulation of K ions in isolated mitochondria from rat myometrium is sensitive to effectors of KATP-channel (ATP-sensitive K+-channel – ATP, diazoxide, glibenclamide and 5HD (5-hydroxydecanoate. Our data demonstrates that K+ uptake in isolated myometrium mitochondria results in a slight decrease in membrane potential, enhancement of generation of ROS (reactive oxygen species and mitochondrial swelling. Particularly, the addition of ATP into incubation medium led to a decrease in mitochondrial swelling and ROS production, and an increase in membrane potential. These effects were eliminated by diazoxide. If blockers of KATP-channel were added along with diazoxide, the effects of diazoxide were removed. So, we postulate the existence of KATP-channels in rat uterus mitochondria and assume that their functioning may regulate physiological conditions of mitochondria, such as matrix volume, ROS generation and polarization of mitochondrial membrane. Keywords: ATP-sensitive potassium channel, Diazoxide, 5-hydroxydecanoate, Myometrium, Mitochondria, Mitochondrial swelling, Mitochondrial membrane potential, ROS

  11. Mitochondria morphologic changes and metabolic effects of rat hippocampus after microwave irradiation

    International Nuclear Information System (INIS)

    Zhao Li; Peng Ruiyun; Gao Yabing; Wang Shuiming; Wang Lifeng; Dong Qi; Xu Xinping; Ma Junjie

    2007-01-01

    Objective: To investigate the effect of microwave on mitochondria morphologic and metabolism of rat hippocampus. Methods: 30 male rats were exposed to microwave with the average power density of 30 mW/cm 2 . Rats were sacrificed at 6 h, 1 d, 3 d and 7 d after irradiation. Electron microscope, enzymatic activity staining and spectrophotometer were used to study ultrastructure change of hippocampus mitochondria and activity of ATPase, SDH and MAO. Mitochondrial ATP, ADP and AMP contents were measured by high performance liquid chromatography (HPLC). Results: At 6 h after microwave radiation, the sizes and shapes of hippocampus mitochondria were abnormal and the injury of mitochondria was aggravated at 1 and 3 d after radiation. The mitochondria presented swell, cavitation including disorder, shortness and decrease of crest. The activity of SDH and content of ATP were decreased at 6 h, most serious at 3 d(P<0.01), and recovered at 7 d after radiation. The activity of ATPase and MAO increased notably at 1 d and 3 d after radiation (P<0.01). Conclusions: Microwave can damage the structure and function of mitochondria in rat hippocampus, and cause the energy metabolism of enzyme disorder. (authors)

  12. Diabetes-Induced Dysfunction of Mitochondria and Stem Cells in Skeletal Muscle and the Nervous System

    Science.gov (United States)

    Fujimaki, Shin; Kuwabara, Tomoko

    2017-01-01

    Diabetes mellitus is one of the most common metabolic diseases spread all over the world, which results in hyperglycemia caused by the breakdown of insulin secretion or insulin action or both. Diabetes has been reported to disrupt the functions and dynamics of mitochondria, which play a fundamental role in regulating metabolic pathways and are crucial to maintain appropriate energy balance. Similar to mitochondria, the functions and the abilities of stem cells are attenuated under diabetic condition in several tissues. In recent years, several studies have suggested that the regulation of mitochondria functions and dynamics is critical for the precise differentiation of stem cells. Importantly, physical exercise is very useful for preventing the diabetic alteration by improving the functions of both mitochondria and stem cells. In the present review, we provide an overview of the diabetic alterations of mitochondria and stem cells and the preventive effects of physical exercise on diabetes, focused on skeletal muscle and the nervous system. We propose physical exercise as a countermeasure for the dysfunction of mitochondria and stem cells in several target tissues under diabetes complication and to improve the physiological function of patients with diabetes, resulting in their quality of life being maintained. PMID:29036909

  13. Calculation of ion currents across the inner membrane of functionally intact mitochondria

    Science.gov (United States)

    Kane, Daniel A; Pavlov, Evgeny V

    2013-01-01

    Mitochondrial ion transport systems play a central role in cell physiology. Rates of Ca2+ and K+ transport across the inner mitochondrial membrane have been derived from the measurement of ion accumulation over time within functional isolated mitochondria or mitochondria of cultured cells. Alternatively, the electrical currents generated by ionic flux have been directly measured in purified and swollen mitochondrial samples (mitoplasts) or reconstituted channels, and typically range from 1 pA to several 100s pA. However, the direct electrophysiological approach necessarily requires extensive processing of the mitochondria prior to measurement, which can only be performed on isolated mitoplasts. To compare rates of mitochondrial ion transport measured in electrophysiological experiments to those measured in intact mitochondria and cells, we converted published rates of mitochondrial ion uptake into units of ionic current. We estimate that for monovalent ions, uptake by intact mitochondria at the rate of 1 nmol ∙ mg−1 protein ∙ min−1 is equivalent to 0.2 fA of current per whole single mitochondrion (0.4 fA for divalent ions). In intact mitochondria, estimated rates of electrogenic cation uptake are limited to 1–100 fA of integral current per single mitochondrion. These estimates are orders of magnitude lower than the currents through mitochondrial channels directly measured via patch-clamp or artificial lipid bilayer approaches. PMID:24037064

  14. UCP3 is associated with Hax-1 in mitochondria in the presence of calcium ion

    Energy Technology Data Exchange (ETDEWEB)

    Hirasaka, Katsuya, E-mail: hirasaka@nagasaki-u.ac.jp [Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki (Japan); Department of Nutritional Physiology, Institute of Health Biosciences, University of Tokushima, Tokushima (Japan); Mills, Edward M. [Division of Pharmacology/Toxicology, University of Texas at Austin, Austin, TX (United States); Haruna, Marie; Bando, Aki; Ikeda, Chika; Abe, Tomoki [Department of Nutritional Physiology, Institute of Health Biosciences, University of Tokushima, Tokushima (Japan); Kohno, Shohei; Nowinski, Sara M. [Division of Pharmacology/Toxicology, University of Texas at Austin, Austin, TX (United States); Lago, Cory U. [Translational Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Akagi, Ken-ichi [Section of Laboratory Equipment, National Institute of Biomedical Innovation, Osaka (Japan); Tochio, Hidehito [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Ohno, Ayako; Teshima-Kondo, Shigetada [Department of Nutritional Physiology, Institute of Health Biosciences, University of Tokushima, Tokushima (Japan); Okumura, Yuushi [Department of Nutrition and Health, Sagami Woman' s University, Kanagawa (Japan); Nikawa, Takeshi [Department of Nutritional Physiology, Institute of Health Biosciences, University of Tokushima, Tokushima (Japan)

    2016-03-25

    Uncoupling protein 3 (UCP3) is known to regulate energy dissipation, proton leakage, fatty acid oxidation, and oxidative stress. To identify the putative protein regulators of UCP3, we performed yeast two-hybrid screens. Here we report that UCP3 interacted with HS-1 associated protein X-1 (Hax-1), an anti-apoptotic protein that was localized in the mitochondria, and is involved in cellular responses to Ca{sup 2+}. The hydrophilic sequences within loop 2, and the matrix-localized hydrophilic domain of mouse UCP3, were necessary for binding to Hax-1 at the C-terminal domain, adjacent to the mitochondrial inner membrane. Interestingly, interaction of these proteins occurred in a calcium-dependent manner. Moreover, the NMR spectrum of the C-terminal domain of Hax-1 was dramatically changed by removal of Ca{sup 2+}, suggesting that the C-terminal domain of Hax-1 underwent a Ca{sup 2+}-induced conformational change. In the Ca{sup 2+}-free state, the C-terminal Hax-1 tended to unfold, suggesting that Ca{sup 2+} binding may induce protein folding of the Hax-1 C-terminus. These results suggested that the UCP3-Hax-1 complex may regulate mitochondrial functional changes caused by mitochondrial Ca{sup 2+}. - Highlights: • UCP3 interacts with Hax-1. • The interaction of UCP3 and Hax-1 occurs in a calcium-dependent manner. • The C-terminal domain of Hax-1 undergoes a calcium-induced conformational change.

  15. Broad genomic and transcriptional analysis reveals a highly derived genome in dinoflagellate mitochondria

    Directory of Open Access Journals (Sweden)

    Keeling Patrick J

    2007-09-01

    Full Text Available Abstract Background Dinoflagellates comprise an ecologically significant and diverse eukaryotic phylum that is sister to the phylum containing apicomplexan endoparasites. The mitochondrial genome of apicomplexans is uniquely reduced in gene content and size, encoding only three proteins and two ribosomal RNAs (rRNAs within a highly compacted 6 kb DNA. Dinoflagellate mitochondrial genomes have been comparatively poorly studied: limited available data suggest some similarities with apicomplexan mitochondrial genomes but an even more radical type of genomic organization. Here, we investigate structure, content and expression of dinoflagellate mitochondrial genomes. Results From two dinoflagellates, Crypthecodinium cohnii and Karlodinium micrum, we generated over 42 kb of mitochondrial genomic data that indicate a reduced gene content paralleling that of mitochondrial genomes in apicomplexans, i.e., only three protein-encoding genes and at least eight conserved components of the highly fragmented large and small subunit rRNAs. Unlike in apicomplexans, dinoflagellate mitochondrial genes occur in multiple copies, often as gene fragments, and in numerous genomic contexts. Analysis of cDNAs suggests several novel aspects of dinoflagellate mitochondrial gene expression. Polycistronic transcripts were found, standard start codons are absent, and oligoadenylation occurs upstream of stop codons, resulting in the absence of termination codons. Transcripts of at least one gene, cox3, are apparently trans-spliced to generate full-length mRNAs. RNA substitutional editing, a process previously identified for mRNAs in dinoflagellate mitochondria, is also implicated in rRNA expression. Conclusion The dinoflagellate mitochondrial genome shares the same gene complement and fragmentation of rRNA genes with its apicomplexan counterpart. However, it also exhibits several unique characteristics. Most notable are the expansion of gene copy numbers and their arrangements

  16. Preventing Mitochondrial Diseases: Embryo-Sparing Donor-Independent Options.

    Science.gov (United States)

    Adashi, Eli Y; Cohen, I Glenn

    2018-05-01

    Mutant mitochondrial DNA gives rise to a broad range of incurable inborn maladies. Prevention may now be possible by replacing the mutation-carrying mitochondria of zygotes or oocytes at risk with donated unaffected counterparts. However, mitochondrial replacement therapy is being held back by theological, ethical, and safety concerns over the loss of human zygotes and the involvement of a donor. These concerns make it plain that the identification, validation, and regulatory adjudication of novel embryo-sparing donor-independent technologies remains a pressing imperative. This Opinion highlights three emerging embryo-sparing donor-independent options that stand to markedly allay theological, ethical, and safety concerns raised by mitochondrial replacement therapy. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Probabilistic conditional independence structures

    CERN Document Server

    Studeny, Milan

    2005-01-01

    Probabilistic Conditional Independence Structures provides the mathematical description of probabilistic conditional independence structures; the author uses non-graphical methods of their description, and takes an algebraic approach.The monograph presents the methods of structural imsets and supermodular functions, and deals with independence implication and equivalence of structural imsets.Motivation, mathematical foundations and areas of application are included, and a rough overview of graphical methods is also given.In particular, the author has been careful to use suitable terminology, and presents the work so that it will be understood by both statisticians, and by researchers in artificial intelligence.The necessary elementary mathematical notions are recalled in an appendix.

  18. Drill machine guidance using natural occurring radiation

    International Nuclear Information System (INIS)

    Dahl, H.D.; Schroeder, R.L.; Williams, B.J.

    1980-01-01

    A drilling machine guidance system is described which uses only the naturally occuring radiation within the seam or stratum of interest. The apparatus can be used for guiding horizontal drilling machines through coal seams and the like. (U.K.)

  19. Multiple Primary Cancers: Simultaneously Occurring Prostate ...

    African Journals Online (AJOL)

    2016-05-20

    May 20, 2016 ... occurring prostate cancer and other primary tumors-our experience and literature ..... thyroid cancers, pancreatic tumors, renal cancers, and melanoma. ... Hsing AW, Yeboah E, Biritwum R, Tettey Y, De Marzo AM,. Adjei A, et ...

  20. GENE TRANSFER IN TOBACCO MITOCHONDRIA IN VITRO AND IN VIVO

    Directory of Open Access Journals (Sweden)

    Katyshev A.I.

    2012-08-01

    Full Text Available Earlier, we had showed that isolated mitochondria from different organisms can import DNA. Exploiting this mechanism, we assessed the possibility of genes transfer in tobacco mitochondria in vitro and in vivo. Whereas homologous recombination is a rare occasion in higher plant nuclei, recombination between the large direct repeats in plant mitochondrial genome generates its multipartite structure. Following transfection of isolated organelles with constructs composed of a partial gfp gene flanked by mitochondrial DNA fragments, we showed the homologous recombination of imported DNA with the resident DNA and the integration of the reporter gene. The recombination yielded an insertion of a continuous exogenous DNA fragment including the gfp sequence and at least the 0.5 kb of the flanking sequence on each side. Using of transfection constructs carrying multiple sequences homologous to mitochondrial DNA could be suitable for insertion of a target gene into any region of the mitochondrial genome, which turns this approach to be of a general and methodical importance. Usually mitochondrial reactive oxygen species (ROS level is under strict control of the antioxidant system including the Mn-containing superoxide dismutase (MnSOD. MnSOD is presented in multiple forms encoded by several genes in plants. Possibly, this enzyme, beside its catalytic function, fulfills as well some unknown biochemical functions. Thus, one of maize SOD enzymes (SOD3.4 could bind with mitochondrial DNA. Another SOD form (SOD3.1 is located in close proximity to mitochondrial respiratory complexes, where ROS are generated. To study possible physiological functions of this enzyme, we cloned the maize SOD3.1 gene. Compared to the SOD3.4, this enzyme didn't demonstrate DNA-binding activity. At the same time, SOD3.1 didn't show non-specific DNA-hydrolyzing activity as Cu/ZnSOD does. It means that this enzyme might have some DNA protective function. We made NtPcob-sod3.1-IGR

  1. High Dietary Fat Selectively Increases Catalase Expression within Cardiac Mitochondria*

    Science.gov (United States)

    Rindler, Paul M.; Plafker, Scott M.; Szweda, Luke I.; Kinter, Michael

    2013-01-01

    Obesity is a predictor of diabetes and cardiovascular disease. One consequence of obesity is dyslipidemia characterized by high blood triglycerides. It has been proposed that oxidative stress, driven by utilization of lipids for energy, contributes to these diseases. The effects of oxidative stress are mitigated by an endogenous antioxidant enzyme network, but little is known about its response to high fat utilization. Our experiments used a multiplexed quantitative proteomics method to measure antioxidant enzyme expression in heart tissue in a mouse model of diet-induced obesity. This experiment showed a rapid and specific up-regulation of catalase protein, with subsequent assays showing increases in activity and mRNA. Catalase, traditionally considered a peroxisomal protein, was found to be present in cardiac mitochondria and significantly increased in content and activity during high fat feeding. These data, coupled with the fact that fatty acid oxidation enhances mitochondrial H2O2 production, suggest that a localized catalase increase is needed to consume excessive mitochondrial H2O2 produced by increased fat metabolism. To determine whether the catalase-specific response is a common feature of physiological conditions that increase blood triglycerides and fatty acid oxidation, we measured changes in antioxidant expression in fasted versus fed mice. Indeed, a similar specific catalase increase was observed in mice fasted for 24 h. Our findings suggest a fundamental metabolic process in which catalase expression is regulated to prevent damage while preserving an H2O2-mediated sensing of diet composition that appropriately adjusts insulin sensitivity in the short term as needed to prioritize lipid metabolism for complete utilization. PMID:23204527

  2. The role of cholesterol in the association of endoplasmic reticulum membranes with mitochondria

    International Nuclear Information System (INIS)

    Fujimoto, Michiko; Hayashi, Teruo; Su, Tsung-Ping

    2012-01-01

    Highlights: ► The endoplasmic reticulum subdomain termed MAM associates with mitochondria. ► The biophysical role of lipids in the MAM–mitochondria association is unknown. ► The in vitro membrane association assay was used to examine the role of lipids. ► Cholesterol was found to negatively regulate the association. -- Abstract: The unique endoplasmic reticulum (ER) subdomain termed the mitochondria-associated ER membrane (MAM) engages the physical connection between the ER and the mitochondrial outer membrane and plays a role in regulating IP 3 receptor-mediated Ca 2+ influx and the phospholipid transport between the two organelles. The MAM contains certain signaling and membrane-tethering proteins but also lipids including cholesterol. The biophysical role of lipids at the MAM, specifically in the physical interaction between the MAM of the ER and mitochondria, remains not totally clarified. Here we employed the in vitro membrane association assay to investigate the role of cholesterol in the association between MAMs and mitochondria. The purified MAMs and mitochondria were mixed in vitro in a test tube and then the physical association of the two subcellular organelles was quantified indirectly by measuring the presence of the MAM-specific protein sigma-1 receptors in the mitochondria fraction. Purified MAMs contained free cholesterol approximately 7 times higher than that in microsomes. We found that depletion of cholesterol in MAMs with methyl-β-cyclodextrin (MβC) significantly increases the association between MAMs and mitochondria, whereas MβC saturated with cholesterol does not change the association. 14 C-Serine pulse-labeling demonstrated that the treatment of living cells with MβC decreases the level of de novo synthesized 14 C-phosphatidylserine (PtSer) and concomitantly increases greatly the synthesis of 14 C-phosphatidylethanolamine (PtEt). Apparently, cholesterol depletion increased the PtSer transport from MAMs to mitochondria. Our

  3. The role of cholesterol in the association of endoplasmic reticulum membranes with mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Michiko [Cellular Stress Signaling Unit, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States); Hayashi, Teruo, E-mail: thayashi@mail.nih.gov [Cellular Stress Signaling Unit, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States); Su, Tsung-Ping, E-mail: tsu@intra.nida.nih.gov [Cellular Pathobiology Section, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer The endoplasmic reticulum subdomain termed MAM associates with mitochondria. Black-Right-Pointing-Pointer The biophysical role of lipids in the MAM-mitochondria association is unknown. Black-Right-Pointing-Pointer The in vitro membrane association assay was used to examine the role of lipids. Black-Right-Pointing-Pointer Cholesterol was found to negatively regulate the association. -- Abstract: The unique endoplasmic reticulum (ER) subdomain termed the mitochondria-associated ER membrane (MAM) engages the physical connection between the ER and the mitochondrial outer membrane and plays a role in regulating IP{sub 3} receptor-mediated Ca{sup 2+} influx and the phospholipid transport between the two organelles. The MAM contains certain signaling and membrane-tethering proteins but also lipids including cholesterol. The biophysical role of lipids at the MAM, specifically in the physical interaction between the MAM of the ER and mitochondria, remains not totally clarified. Here we employed the in vitro membrane association assay to investigate the role of cholesterol in the association between MAMs and mitochondria. The purified MAMs and mitochondria were mixed in vitro in a test tube and then the physical association of the two subcellular organelles was quantified indirectly by measuring the presence of the MAM-specific protein sigma-1 receptors in the mitochondria fraction. Purified MAMs contained free cholesterol approximately 7 times higher than that in microsomes. We found that depletion of cholesterol in MAMs with methyl-{beta}-cyclodextrin (M{beta}C) significantly increases the association between MAMs and mitochondria, whereas M{beta}C saturated with cholesterol does not change the association. {sup 14}C-Serine pulse-labeling demonstrated that the treatment of living cells with M{beta}C decreases the level of de novo synthesized {sup 14}C-phosphatidylserine (PtSer) and concomitantly increases greatly the synthesis of

  4. Localization of age-related macular degeneration-associated ARMS2 in cytosol, not mitochondria

    Science.gov (United States)

    Wang, Gaofeng; Spencer, Kylee L.; Court, Brenda L.; Olson, Lana M.; Scott, William K.; Haines, Jonathan L.; Pericak-Vance, Margaret A.

    2010-01-01

    PURPOSE To analyze the relationship between ARMS2 and HTRA1 in the association with age-related macular degeneration (AMD) in an independent case-control dataset, and to investigate the subcellular localization of the ARMS2 protein in an in vitro system. METHOD Two SNPs in ARMS2 and HTRA1 were genotyped in 685 cases and 269 controls by Taqman Assay. Allelic association was tested by a χ2 test. A likelihood ratio test (LRT) of full vs. reduced models was utilized to analyze the interaction between ARMS2 and smoking and HTRA1 and smoking, after adjusting for CFH and age. Immunofluorescence and immunoblot were applied to localize ARMS2 in retinal epithelial ARPE-19 cells and COS7 cell transfected by ARMS2 constructs. RESULT Both significantly associated SNP rs10490924 and rs11200638 (P<0.0001) are in strong linkage disequilibrium (LD) (D′=0.97, r2=0.93) that generates virtually identical association test and odds ratios. In separate logistic regression models the interaction effect for both smoking with ARMS2 and with HTRA1 was not statistically significant. Immunofluorescence and immunoblot show that both endogenous and exogenous ARMS2 are mainly distributed in the cytosol, not the mitochondria. Comparing to wild type, ARMS2 A69S is more likely to be associated with cytoskeleton in COS7 cells. CONCLUSIONS The significant associations in ARMS2 and HTRA1 are with polymorphisms in strong LD that confer virtually identical risks, preventing differentiation at the statistical level. We found that ARMS2 was mainly distributed in the cytosol, not in mitochondrial outer membrane as previously reported, suggesting that ARMS2 may not confer risk to AMD through the mitochondrial pathway. PMID:19255159

  5. Feedback regulation of mitochondria by caspase-9 in the B cell receptor-mediated apoptosis.

    Science.gov (United States)

    Eeva, J; Nuutinen, U; Ropponen, A; Mättö, M; Eray, M; Pellinen, R; Wahlfors, J; Pelkonen, J

    2009-12-01

    During the germinal centre reaction (GC), B cells with non-functional or self-reactive antigen receptors are negatively selected by apoptosis to generate B cell repertoire with appropriate antigen specificities. We studied the molecular mechanism of Fas/CD95- and B cell receptor (BCR)-induced apoptosis to shed light on the signalling events involved in the negative selection of GC B cells. As an experimental model, we used human follicular lymphoma (FL) cell line HF1A3, which originates from a GC B cell, and transfected HF1A3 cell lines overexpressing Bcl-x(L), c-FLIP(long) or dominant negative (DN) caspase-9. Fas-induced apoptosis was dependent on the caspase-8 activation, since the overexpression of c-FLIP(long), a natural inhibitor of caspase-8 activation, blocked apoptosis induced by Fas. In contrast, caspase-9 activation was not involved in Fas-induced apoptosis. BCR-induced apoptosis showed the typical characteristics of mitochondria-dependent (intrinsic) apoptosis. Firstly, the activation of caspase-9 was involved in BCR-induced DNA fragmentation, while caspase-8 showed only marginal role. Secondly, overexpression of Bcl-x(L) could block all apoptotic changes induced by BCR. As a novel finding, we demonstrate that caspase-9 can enhance the cytochrome-c release and collapse of mitochondrial membrane potential (DeltaPsi(m)) during BCR-induced apoptosis. The requirement of different signalling pathways in apoptosis induced by BCR and Fas may be relevant, since Fas- and BCR-induced apoptosis can thus be regulated independently, and targeted to different subsets of GC B cells.

  6. Mitochondria-Targeted Nitroxide, Mito-CP, Suppresses Medullary Thyroid Carcinoma Cell Survival In Vitro and In Vivo

    Science.gov (United States)

    Starenki, Dmytro

    2013-01-01

    Context: Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor mainly caused by mutations in the RET proto-oncogene. For MTC therapy, the U.S. Food and Drug Administration recently approved vandetanib and cabozantinib, multikinase inhibitors targeting RET and other tyrosine kinase receptors of vascular endothelial growth factor, epidermal growth factor, or hepatocyte growth factor. Nevertheless, not all patients with the progressive MTC respond to these drugs, requiring the development of additional therapeutic modalities that have distinct activity. Objective: We aimed to evaluate mitochondria-targeted carboxy-proxyl (Mito-CP), a mitochondria-targeted redox-sensitive agent, for its tumor-suppressive efficacy against MTC. Design: In vitro cultures of 2 human MTC cell lines, TT and MZ-CRC-1, and TT xenografts in mice were treated with Mito-CP in comparison with vandetanib. The effects on cell survival/death, RET expression, mitochondrial integrity, and oxidative stress were determined. Results: Contrary to vandetanib, Mito-CP induced RET downregulation and strong cytotoxic effects in both cell lines in vitro, including caspase-dependent apoptosis. These effects were accompanied by mitochondrial membrane depolarization, decreased oxygen consumption, and increased oxidative stress in cells. Intriguingly, Mito-CP–induced cell death, but not RET downregulation, was partially inhibited by the reactive oxygen species scavenger, N-acetyl-cysteine, indicating that Mito-CP mediates tumor-suppressive effects via redox-dependent as well as redox-independent mechanisms. Orally administered Mito-CP effectively suppressed TT xenografts in mice, with an efficacy comparable to vandetanib and relatively low toxicity to animals. Conclusion: Our results suggest that Mito-CP can effectively suppress MTC cell growth/survival via a mechanism distinct from vandetanib effects. Mitochondrial targeting may be a potential strategy for MTC therapy. PMID:23509102

  7. Ca2+ Transport by Mitochondria from L1210 Mouse Ascites Tumor Cells

    Science.gov (United States)

    Reynafarje, Baltazar; Lehninger, Albert L.

    1973-01-01

    Mitochondria isolated from the ascites form of L1210 mouse leukemia cells readily accumulate Ca2+ from the suspending medium and eject H+ during oxidation of succinate in the presence of phosphate and Mg2+, with normal stoichiometry between Ca2+ uptake and electron transport. Ca2+ loads up to 1600 ng-atoms per mg of protein are attained. As is the case in mitochondria from normal tissues, Ca2+ uptake takes precedence over oxidative phosphorylation. However, Ca2+ transport by the L-1210 mitochondria is unusual in other respects, which may possibly have general significance in tumor cells. The apparent affinity of the L1210 mitochondria for Ca2+ in stimulation of oxygen uptake is about 3-fold greater than in normal liver mitochondria; moreover, the maximal rate of Ca2+ transport is also considerably higher. Furthermore, when Ca2+ pulses are added to L1210 mitochondria in the absence of phosphate or other permeant anions, much larger amounts of Ca2+ are bound and H+ ejected per atom of oxygen consumed than in the presence of phosphate; up to 7 Ca2+ ions are bound per pair of electrons passing each energy-conserving site of the electron-transport chain. Such “superstoichiometry” of Ca2+ uptake can be accounted for by two distinct types of respiration-dependent interaction of Ca2+ with the L1210 mitochondria. One is the stimulation of oxygen consumption, which is achieved by relatively low concentrations of Ca2+ (Km ≅ 8 μM) and is accompanied by binding of Ca2+ up to 40 ng-atoms per mg of protein. The second process, also dependent on electron transport, is the binding of further Ca2+ from the medium in exchange with previously stored membrane-bound protons, in which the affinity for Ca2+ is much lower (Km ≅ 120 μM). PMID:4515933

  8. Determination of natural occurring radionuclides concentrations

    International Nuclear Information System (INIS)

    Stajic, J.; Markovic, V.; Krstic, D.; Nikezic, D.

    2011-01-01

    Tobacco smoke contains certain concentrations of naturally occurring radionuclides from radioactive chains of uranium and thorium - 214 Pb, 214 Bi, 228 Ac, 208 Tl, 226 Ra, 232 Th and 40 K. Inhaling of tobacco smoke leads to internal exposure of man. In order to estimate absorbed dose of irradiation it is necessary to determine concentrations of radionuclides present in the tobacco leaves. In this paper specific activities of naturally occurring radionuclides were measured in tobacco samples from cigarettes which are used in Serbia. [sr

  9. When modularization fails to occur: a developmental perspective.

    Science.gov (United States)

    D'Souza, Dean; Karmiloff-Smith, Annette

    2011-05-01

    We argue that models of adult cognition defined in terms of independently functioning modules cannot be applied to development, whether typical or atypical. The infant brain starts out highly interconnected, and it is only over developmental time that neural networks become increasingly specialized-that is, relatively modularized. In the case of atypical development, even when behavioural scores fall within the normal range, they are frequently underpinned by different cognitive and neural processes. In other words, in neurodevelopmental disorders the gradual process of relative modularization may fail to occur.

  10. Features of the postirradiation regeneration of liver mitochondria of gamma-irradiated mice treated with the Testudo horsfieldi spleen extract

    Energy Technology Data Exchange (ETDEWEB)

    Turdyev, A.A.; Ivanov, V.I.; Trifonov, Yu.A.; Abbasova, I.A.; Usmanov, R.B.

    A study was made of the effect of a drug prepared from a spleen extract of Testudo horsfieldi on energy metabolism and lipid composition of liver mitochondria of irradiated mice (2.06 x 10/sup -1/ C/kg). It was shown that the decompensated low-energy state of liver mitochondria of the exposed mice was changed into the state of the compensated low-energy shift: the physicochemical properties of lipid microenvironment of mitochondria proteins were partially restored.

  11. Independent technical review, handbook

    International Nuclear Information System (INIS)

    1994-02-01

    Purpose Provide an independent engineering review of the major projects being funded by the Department of Energy, Office of Environmental Restoration and Waste Management. The independent engineering review will address questions of whether the engineering practice is sufficiently developed to a point where a major project can be executed without significant technical problems. The independent review will focus on questions related to: (1) Adequacy of development of the technical base of understanding; (2) Status of development and availability of technology among the various alternatives; (3) Status and availability of the industrial infrastructure to support project design, equipment fabrication, facility construction, and process and program/project operation; (4) Adequacy of the design effort to provide a sound foundation to support execution of project; (5) Ability of the organization to fully integrate the system, and direct, manage, and control the execution of a complex major project

  12. Independent technical review, handbook

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    Purpose Provide an independent engineering review of the major projects being funded by the Department of Energy, Office of Environmental Restoration and Waste Management. The independent engineering review will address questions of whether the engineering practice is sufficiently developed to a point where a major project can be executed without significant technical problems. The independent review will focus on questions related to: (1) Adequacy of development of the technical base of understanding; (2) Status of development and availability of technology among the various alternatives; (3) Status and availability of the industrial infrastructure to support project design, equipment fabrication, facility construction, and process and program/project operation; (4) Adequacy of the design effort to provide a sound foundation to support execution of project; (5) Ability of the organization to fully integrate the system, and direct, manage, and control the execution of a complex major project.

  13. Detection of Harmonic Occurring using Kalman Filtering

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar; Shoro, Ghulam Mustafa; Imran, Raja Muhammed

    2014-01-01

    /current characteristic. These harmonics are not to be allowed to grow beyond a certain limit to avoid any grave consequence to the customer’s main supply. Filters can be implemented at the power source or utility location to eliminate these harmonics. In this paper we detect the instance at which these harmonics occur...

  14. Formal synthesis of naturally occurring norephedrine

    Indian Academy of Sciences (India)

    A concise and simple synthesis of 1-hydroxy-phenethylamine derivatives has been achieved following classical organic transformations using commercially available chiral pools. The said derivatives were explored for the synthesis of naturally occurring bio-active small molecules. Formal synthesis of norephedrine, virolin ...

  15. Percieved functions of naturally occurring autobiographical memories

    DEFF Research Database (Denmark)

    Treebak, L. S.; Henriksen, J. R.; Lundhus, S.

    2005-01-01

    The main empirical reference on functions of autobiographical memories is still Hyman & Faries (1992) who used the cue-word-method and retrospective judgements. We used diaries to sample naturally occurring autobiographical memories and participants? perceived use of these. Results partly replicate...

  16. A naturally occurring trap for antiprotons

    International Nuclear Information System (INIS)

    Eades, J.; Morita, N.; Ito, T.M.

    1993-05-01

    The phenomenon of delayed annihilation of antiprotons in helium is the first instance of a naturally occurring trap for antimatter in ordinary matter. Recent studies of this effect at CERN are summarized, and plans are described for laser excitation experiments to test its interpretation in terms of metastable exotic helium atom formation. (author)

  17. Jerky periods: myoclonus occurring solely during menses

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; Gelauff, Jeannette M.; van der Salm, Sandra M. A.; Tijssen, Marina A. J.; van Rootselaar, Anne-Fleur

    2013-01-01

    In this case report, we describe an unusual case of a patient with myoclonus only occurring during menses. A 41-year-old female, known to have neurological sequelae after a car accident 1 year earlier, presented with myoclonic movements of the right arm and hand only during menses. Brain magnetic

  18. Preferential flow occurs in unsaturated conditions

    Science.gov (United States)

    Nimmo, John R.

    2012-01-01

    Because it commonly generates high-speed, high-volume flow with minimal exposure to solid earth materials, preferential flow in the unsaturated zone is a dominant influence in many problems of infiltration, recharge, contaminant transport, and ecohydrology. By definition, preferential flow occurs in a portion of a medium – that is, a preferred part, whether a pathway, pore, or macroscopic subvolume. There are many possible classification schemes, but usual consideration of preferential flow includes macropore or fracture flow, funneled flow determined by macroscale heterogeneities, and fingered flow determined by hydraulic instability rather than intrinsic heterogeneity. That preferential flow is spatially concentrated associates it with other characteristics that are typical, although not defining: it tends to be unusually fast, to transport high fluxes, and to occur with hydraulic disequilibrium within the medium. It also has a tendency to occur in association with large conduits and high water content, although these are less universal than is commonly assumed. Predictive unsaturated-zone flow models in common use employ several different criteria for when and where preferential flow occurs, almost always requiring a nearly saturated medium. A threshold to be exceeded may be specified in terms of the following (i) water content; (ii) matric potential, typically a value high enough to cause capillary filling in a macropore of minimum size; (iii) infiltration capacity or other indication of incipient surface ponding; or (iv) other conditions related to total filling of certain pores. Yet preferential flow does occur without meeting these criteria. My purpose in this commentary is to point out important exceptions and implications of ignoring them. Some of these pertain mainly to macropore flow, others to fingered or funneled flow, and others to combined or undifferentiated flow modes.

  19. DISC1 Modulates Neuronal Stress Responses by Gate-Keeping ER-Mitochondria Ca2+ Transfer through the MAM

    Directory of Open Access Journals (Sweden)

    Sung Jin Park

    2017-12-01

    Full Text Available Summary: A wide range of Ca2+-mediated functions are enabled by the dynamic properties of Ca2+, all of which are dependent on the endoplasmic reticulum (ER and mitochondria. Disrupted-in-schizophrenia 1 (DISC1 is a scaffold protein that is involved in the function of intracellular organelles and is linked to cognitive and emotional deficits. Here, we demonstrate that DISC1 localizes to the mitochondria-associated ER membrane (MAM. At the MAM, DISC1 interacts with IP3R1 and downregulates its ligand binding, modulating ER-mitochondria Ca2+ transfer through the MAM. The disrupted regulation of Ca2+ transfer caused by DISC1 dysfunction leads to abnormal Ca2+ accumulation in mitochondria following oxidative stress, which impairs mitochondrial functions. DISC1 dysfunction alters corticosterone-induced mitochondrial Ca2+ accumulation in an oxidative stress-dependent manner. Together, these findings link stress-associated neural stimuli with intracellular ER-mitochondria Ca2+ crosstalk via DISC1, providing mechanistic insight into how environmental risk factors can be interpreted by intracellular pathways under the control of genetic components in neurons. : Park et al. show that DISC1 regulates ER-mitochondria Ca2+ transfer through mitochondria-associated ER membrane (MAM. DISC1 dysfunction at MAM increases ER-mitochondria Ca2+ transfer during oxidative stress and excessive amounts of corticosterone, which impairs mitochondrial function. Keywords: DISC1, MAM, mitochondria, Ca2+, IP3R1, oxidative stress

  20. Carprofen-induced oxidative stress in mitochondria of the colonic mucosa of the dog.

    Science.gov (United States)

    Snow, Lynne A; McConnico, Rebecca S; Morgan, Timothy W; Hartmann, Erica; Davidson, Jacqueline R; Hosgood, Giselle

    2014-07-01

    The purpose of the study was to compare the conductance and mannitol permeability of canine colonic mucosa in response to carprofen or 2,4-dinitrophenol (DNP) with or without tempol pretreatment. Ten colonic mucosa sections per dog were mounted in Ussing chambers. Treatments were done in duplicate. Mucosa was exposed to carprofen (200 μg/mL) or DNP (0.25 mM), both with and without tempol (1 mM) pretreatment. Conductance was calculated every 15 min for 240 min. Mannitol flux was calculated over 3 consecutive 60-minute periods. Histology or electron microscopy was done after exposure. Conductance over time, mannitol flux, frequency of histologic categories, and electron microscopic changes were analyzed for treatment effects. The mean ± standard deviation (SD) conductance over time for carprofen or DNP-treated colons was not significantly different from control regardless of tempol pretreatment. Period 3 mannitol fluxes for carprofen and DNP-treated colon were not significantly different, but were greater than control. Period 3 mannitol flux for tempol + carprofen was significantly less than tempol + DNP-treated colon. Sloughing of cells and erosions were seen in the mucosa of carprofen-treated colon. Mitochondrial damage was seen more often in carprofen-treated than DNP-treated or control colon. Tempol pretreatment resulted in more ruptured mitochondria in the carprofen-treated colon; however, other mitochondrial changes were not significantly affected by tempol pretreatment in either carprofen or DNP treated colon. Treatment with carprofen or DNP increased the mannitol flux, but pretreatment with tempol mitigated the carprofen effect. It is apparent that structural mitochondrial damage occurs in the canine colonic mucosa after carprofen and DNP exposure.

  1. Calcium Handling by Endoplasmic Reticulum and Mitochondria in a Cell Model of Huntington’s Disease

    Science.gov (United States)

    De Mario, Agnese; Scarlatti, Chiara; Costiniti, Veronica; Primerano, Simona; Lopreiato, Raffaele; Calì, Tito; Brini, Marisa; Giacomello, Marta; Carafoli, Ernesto

    2016-01-01

    Huntington disease (HD) is caused by the CAG (Q) expansion in exon 1 of the IT15 gene encoding a polyglutamine (poly-Q) stretch of the Huntingtin protein (Htt). In the wild type protein, the repeats specify a stretch of up 34 Q in the N-terminal portion of Htt. In the pathological protein (mHtt) the poly-Q tract is longer. Proteolytic cleavage of the protein liberates an N-terminal fragment containing the expanded poly-Q tract becomes harmful to cells, in particular to striatal neurons. The fragments cause the transcriptional dysfunction of genes that are essential for neuronal survival. Htt, however, could also have non-transcriptional effects, e.g. it could directly alter Ca2+ homeostasis and/or mitochondrial morphology and function. Ca2+ dyshomeostasis and mitochondrial dysfunction are considered important in the molecular aetiology of the disease. Here we have analyzed the effect of the overexpression of Htt fragments (18Q, wild type form, wtHtt and 150Q mutated form, mHtt) on Ca2+ homeostasis in striatal neuronal precursor cells (Q7/7). We have found that the transient overexpression of the Htt fragments increases Ca2+ transients in the mitochondria of cells stimulated with Ca2+-mobilizing agonists. The bulk Ca2+ transients in the cytosol were unaffected, but the Ca2+ content of the endoplasmic reticulum was significantly decreased in the case of mHtt expression. To rule out possible transcriptional effects due to the presence of mHtt, we have measured the mRNA level of a subunit of the respiratory chain complex II, whose expression is commonly altered in many HD models. No effects on the mRNA level was found suggesting that, in our experimental condition, transcriptional action of Htt is not occurring and that the effects on Ca2+ homeostasis were dependent to non-transcriptional mechanisms. PMID:26819834

  2. Calcium Handling by Endoplasmic Reticulum and Mitochondria in a Cell Model of Huntington's Disease.

    Science.gov (United States)

    De Mario, Agnese; Scarlatti, Chiara; Costiniti, Veronica; Primerano, Simona; Lopreiato, Raffaele; Calì, Tito; Brini, Marisa; Giacomello, Marta; Carafoli, Ernesto

    2016-01-06

    Huntington disease (HD) is caused by the CAG (Q) expansion in exon 1 of the IT15 gene encoding a polyglutamine (poly-Q) stretch of the Huntingtin protein (Htt). In the wild type protein, the repeats specify a stretch of up 34 Q in the N-terminal portion of Htt. In the pathological protein (mHtt) the poly-Q tract is longer. Proteolytic cleavage of the protein liberates an N-terminal fragment containing the expanded poly-Q tract becomes harmful to cells, in particular to striatal neurons. The fragments cause the transcriptional dysfunction of genes that are essential for neuronal survival. Htt, however, could also have non-transcriptional effects, e.g. it could directly alter Ca2+ homeostasis and/or mitochondrial morphology and function. Ca2+ dyshomeostasis and mitochondrial dysfunction are considered important in the molecular aetiology of the disease. Here we have analyzed the effect of the overexpression of Htt fragments (18Q, wild type form, wtHtt and 150Q mutated form, mHtt) on Ca2+ homeostasis in striatal neuronal precursor cells (Q7/7). We have found that the transient overexpression of the Htt fragments increases Ca2+ transients in the mitochondria of cells stimulated with Ca2+-mobilizing agonists. The bulk Ca2+ transients in the cytosol were unaffected, but the Ca2+ content of the endoplasmic reticulum was significantly decreased in the case of mHtt expression. To rule out possible transcriptional effects due to the presence of mHtt, we have measured the mRNA level of a subunit of the respiratory chain complex II, whose expression is commonly altered in many HD models. No effects on the mRNA level was found suggesting that, in our experimental condition, transcriptional action of Htt is not occurring and that the effects on Ca2+ homeostasis were dependent to non-transcriptional mechanisms.

  3. Warburg and Crabtree effects in premalignant Barrett's esophagus cell lines with active mitochondria.

    Directory of Open Access Journals (Sweden)

    Martin T Suchorolski

    Full Text Available BACKGROUND: Increased glycolysis is a hallmark of cancer metabolism, yet relatively little is known about this phenotype at premalignant stages of progression. Periodic ischemia occurs in the premalignant condition Barrett's esophagus (BE due to tissue damage from chronic acid-bile reflux and may select for early adaptations to hypoxia, including upregulation of glycolysis. METHODOLOGY/PRINCIPAL FINDINGS: We compared rates of glycolysis and oxidative phosphorylation in four cell lines derived from patients with BE (CP-A, CP-B, CP-C and CP-D in response to metabolic inhibitors and changes in glucose concentration. We report that cell lines derived from patients with more advanced genetically unstable BE have up to two-fold higher glycolysis compared to a cell line derived from a patient with early genetically stable BE; however, all cell lines preserve active mitochondria. In response to the glycolytic inhibitor 2-deoxyglucose, the most glycolytic cell lines (CP-C and CP-D had the greatest suppression of extra-cellular acidification, but were able to compensate with upregulation of oxidative phosphorylation. In addition, these cell lines showed the lowest compensatory increases in glycolysis in response to mitochondrial uncoupling by 2,4-dinitrophenol. Finally, these cell lines also upregulated their oxidative phosphorylation in response to glucose via the Crabtree effect, and demonstrate a greater range of modulation of oxygen consumption. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that cells from premalignant Barrett's esophagus tissue may adapt to an ever-changing selective microenvironment through changes in energy metabolic pathways typically associated with cancer cells.

  4. Mitochondria and ageing: role in heart, skeletal muscle and adipose tissue

    Science.gov (United States)

    Boengler, Kerstin; Kosiol, Maik; Mayr, Manuel; Schulz, Rainer

    2017-01-01

    Abstract Age is the most important risk factor for most diseases. Mitochondria play a central role in bioenergetics and metabolism. In addition, several lines of evidence indicate the impact of mitochondria in lifespan determination and ageing. The best‐known hypothesis to explain ageing is the free radical theory, which proposes that cells, organs, and organisms age because they accumulate reactive oxygen species (ROS) damage over time. Mitochondria play a central role as the principle source of intracellular ROS, which are mainly formed at the level of complex I and III of the respiratory chain. Dysfunctional mitochondria generating less ATP have been observed in various aged organs. Mitochondrial dysfunction comprises different features including reduced mitochondrial content, altered mitochondrial morphology, reduced activity of the complexes of the electron transport chain, opening of the mitochondrial permeability transition pore, and increased ROS formation. Furthermore, abnormalities in mitochondrial quality control or defects in mitochondrial dynamics have also been linked to senescence. Among the tissues affected by mitochondrial dysfunction are those with a high‐energy demand and thus high mitochondrial content. Therefore, the present review focuses on the impact of mitochondria in the ageing process of heart and skeletal muscle. In this article, we review different aspects of mitochondrial dysfunction and discuss potential therapeutic strategies to improve mitochondrial function. Finally, novel aspects of adipose tissue biology and their involvement in the ageing process are discussed. PMID:28432755

  5. The Rice Mitochondria Proteome and its Response During Development and to the Environment

    Directory of Open Access Journals (Sweden)

    Shaobai eHuang

    2013-02-01

    Full Text Available Rice (Oryza sativa L. is both a major crop species and the key model grass for molecular and physiological research. Mitochondria are important in rice, as in all crops, as the main source of ATP for cell maintenance and growth. However, the practical significance of understanding the function of mitochondria in rice is increased by the widespread farming practice of using hybrids to boost rice production. This relies on cytoplasmic male-sterile (CMS lines with abortive pollen caused by dysfunctional mitochondria. We provide an overview of what is known about the mitochondrial proteome of rice seedlings. To date, more than 320 proteins have been identified in purified rice mitochondria using mass spectrometry. The insights from this work include a broad understanding of the major subunits of mitochondrial respiratory complexes and TCA cycle enzymes, carbon and nitrogen metabolism enzymes as well as details of the supporting machinery for biogenesis and the subset of stress-responsive mitochondrial proteins. Many proteins with unknown functions have also been found in rice mitochondria. Proteomic analysis has also revealed the features of rice mitochondrial protein presequences required for mitochondrial targeting, as well as cleavage site features for processing of precursors after import. Changes in the abundance of rice mitochondrial proteins in response to different stresses, especially anoxia and light, are summarized. Future research on quantitative analysis of the rice mitochondrial proteomes at the spatial and developmental level, its response to environmental stresses and recent advances in understanding of basis of rice CMS systems are highlighted.

  6. Dual peptide conjugation strategy for improved cellular uptake and mitochondria targeting.

    Science.gov (United States)

    Lin, Ran; Zhang, Pengcheng; Cheetham, Andrew G; Walston, Jeremy; Abadir, Peter; Cui, Honggang

    2015-01-21

    Mitochondria are critical regulators of cellular function and survival. Delivery of therapeutic and diagnostic agents into mitochondria is a challenging task in modern pharmacology because the molecule to be delivered needs to first overcome the cell membrane barrier and then be able to actively target the intracellular organelle. Current strategy of conjugating either a cell penetrating peptide (CPP) or a subcellular targeting sequence to the molecule of interest only has limited success. We report here a dual peptide conjugation strategy to achieve effective delivery of a non-membrane-penetrating dye 5-carboxyfluorescein (5-FAM) into mitochondria through the incorporation of both a mitochondrial targeting sequence (MTS) and a CPP into one conjugated molecule. Notably, circular dichroism studies reveal that the combined use of α-helix and PPII-like secondary structures has an unexpected, synergistic contribution to the internalization of the conjugate. Our results suggest that although the use of positively charged MTS peptide allows for improved targeting of mitochondria, with MTS alone it showed poor cellular uptake. With further covalent linkage of the MTS-5-FAM conjugate to a CPP sequence (R8), the dually conjugated molecule was found to show both improved cellular uptake and effective mitochondria targeting. We believe these results offer important insight into the rational design of peptide conjugates for intracellular delivery.

  7. A Powerful Mitochondria-Targeted Iron Chelator Affords High Photoprotection against Solar Ultraviolet A Radiation.

    Science.gov (United States)

    Reelfs, Olivier; Abbate, Vincenzo; Hider, Robert C; Pourzand, Charareh

    2016-08-01

    Mitochondria are the principal destination for labile iron, making these organelles particularly susceptible to oxidative damage on exposure to ultraviolet A (UVA, 320-400 nm), the oxidizing component of sunlight. The labile iron-mediated oxidative damage caused by UVA to mitochondria leads to necrotic cell death via adenosine triphosphate depletion. Therefore, targeted removal of mitochondrial labile iron via highly specific tools from these organelles may be an effective approach to protect the skin cells against the harmful effects of UVA. In this work, we designed a mitochondria-targeted hexadentate (tricatechol-based) iron chelator linked to mitochondria-homing SS-like peptides. The photoprotective potential of this compound against UVA-induced oxidative damage and cell death was evaluated in cultured primary skin fibroblasts. Our results show that this compound provides unprecedented protection against UVA-induced mitochondrial damage, adenosine triphosphate depletion, and the ensuing necrotic cell death in skin fibroblasts, and this effect is fully related to its potent iron-chelating property in the organelle. This mitochondria-targeted iron chelator has therefore promising potential for skin photoprotection against the deleterious effects of the UVA component of sunlight. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Swelling and functional disorders of isolated liver mitochondria induced by ultraviolet light exposure

    International Nuclear Information System (INIS)

    Sayanagi, Hideaki

    1977-01-01

    Biochemical and morphological disruption of liver mitochondria exposed to ultraviolet light were discussed. The mitochondria was prepared from rat liver, and the suspension was exposed to a broad spectrum ultraviolet light. The ultraviolet exposure of isolated rat liver mitochondria prepared from group 1 (regular laboratory chow), caused the great acceleration of swelling of mitochondria and the loss of the ability to couple the phosphorylation with respiration chain. The irradiated mitochondria produced an increase of lipid peroxide which was proportional to the dose of ultraviolet energy. By the use of a difference spectra technic, the absorption bands of cytochrome b, c (c 1 ), and flavoprotein were found to decrease in absorption after ultraviolet exposure. However, mitochondrial suspension prepared from rat in group 2 (regular chow supplemented with 3 mg% riboflavin free form), 3 (with 3 mg% riboflavin tetrabutyrate), 4 (with 5 mg% glutathione (GSH)), provided some degree of protection against the above deleterious effects of ultraviolet radiation. The irradiation effects could be reduced in the irradiated mitochondrial suspension which was incubated with riboflavin and GSH respectively after exposure. Riboflavin B 2 tetrabutyrate was found to show the significant effect of anti-oxidation. Riboflavin free-form was also active in this respect but to a lesser extent. (auth.)

  9. Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis

    International Nuclear Information System (INIS)

    Graaf, Aniek O. de; Heuvel, Lambert P. van den; Dijkman, Henry B.P.M.; Abreu, Ronney A. de; Birkenkamp, Kim U.; Witte, Theo de; Reijden, Bert A. van der; Smeitink, Jan A.M.; Jansen, Joop H.

    2004-01-01

    Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity

  10. Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis.

    Science.gov (United States)

    de Graaf, Aniek O; van den Heuvel, Lambert P; Dijkman, Henry B P M; de Abreu, Ronney A; Birkenkamp, Kim U; de Witte, Theo; van der Reijden, Bert A; Smeitink, Jan A M; Jansen, Joop H

    2004-10-01

    Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity.

  11. Plasma Amino Acids Stimulate Uncoupled Respiration of Muscle Subsarcolemmal Mitochondria in Lean but Not Obese Humans.

    Science.gov (United States)

    Kras, Katon A; Hoffman, Nyssa; Roust, Lori R; Patel, Shivam H; Carroll, Chad C; Katsanos, Christos S

    2017-12-01

    Obesity is associated with mitochondrial dysfunction in skeletal muscle. Increasing the plasma amino acid (AA) concentrations stimulates mitochondrial adenosine triphosphate (ATP) production in lean individuals. To determine whether acute elevation in plasma AAs enhances muscle mitochondrial respiration and ATP production in subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria in obese adults. Assessment of SS and IMF mitochondrial function during saline (i.e., control) and AA infusions. Eligible participants were healthy lean (body mass index, mass index >30 kg/m2; age 35 ± 3 years; n = 11) subjects. Single trial of saline infusion followed by AA infusion. SS and IMF mitochondria were isolated from muscle biopsies collected at the end of the saline and AA infusions. Mitochondrial respiration and ATP production. AA infusion increased adenosine 5'-diphosphate (ADP)-stimulated respiration and ATP production rates of SS mitochondria in the lean (P lean subjects only (P lean or obese subjects (P > 0.05). Increasing the plasma AA concentrations enhances the capacity for respiration and ATP production of muscle SS, but not IMF, mitochondria in lean individuals, in parallel with increases in uncoupled respiration. However, neither of these parameters increases in muscle SS or IMF mitochondria in obese individuals. Copyright © 2017 Endocrine Society

  12. Changes in oxidative properties of Kalanchoe blossfeldiana leaf mitochondria during development of Crassulacean acid metabolism.

    Science.gov (United States)

    Rustin, P; Queiroz-Claret, C

    1985-06-01

    Kalanchoe blossfeldiana plants grown under long days (16 h light) exhibit a C3-type photosynthetic metabolism. Switching to short days (9 h light) leads to a gradual development of Crassulacean acid metabolism (CAM). Under the latter conditions, dark CO2 fixation produces large amounts of malate. During the first hours of the day, malate is rapidly decarboxylated into pyruvate through the action of a cytosolic NADP(+)-or a mitochondrial NAD(+)-dependent malic enzyme. Mitochondria were isolated from leaves of plants grown under long days or after treatment by an increasing number of short days. Tricarboxylic acid cycle intermediates as well as exogenous NADH and NADPH were readily oxidized by mitochondria isolated from the two types of plants. Glycine, known to be oxidized by C3-plant mitochondria, was still oxidized after CAM establishment. The experiments showed a marked parallelism in the increase of CAM level and the increase in substrate-oxidation capacity of the isolated mitochondria, particularly the capacity to oxidize malate in the presence of cyanide. These simultaneous variations in CAM level and in mitochondrial properties indicate that the mitochondrial NAD(+)-malic enzyme could account at least for a part of the oxidation of malate. The studies of whole-leaf respiration establish that mitochondria are implicated in malate degradation in vivo. Moreover, an increase in cyanide resistance of the leaf respiration has been observed during the first daylight hours, when malate was oxidized to pyruvate by cytosolic and mitochondrial malic enzymes.

  13. Model-Independent Diffs

    DEFF Research Database (Denmark)

    Könemann, Patrick

    just contain a list of strings, one for each line, whereas the structure of models is defined by their meta models. There are tools available which are able to compute the diff between two models, e.g. RSA or EMF Compare. However, their diff is not model-independent, i.e. it refers to the models...

  14. All Those Independent Variables.

    Science.gov (United States)

    Meacham, Merle L.

    This paper presents a case study of a sixth grade remedial math class which illustrates the thesis that only the "experimental attitude," not the "experimental method," is appropriate in the classroom. The thesis is based on the fact that too many independent variables exist in a classroom situation to allow precise measurement. The case study…

  15. Bayesian Independent Component Analysis

    DEFF Research Database (Denmark)

    Winther, Ole; Petersen, Kaare Brandt

    2007-01-01

    In this paper we present an empirical Bayesian framework for independent component analysis. The framework provides estimates of the sources, the mixing matrix and the noise parameters, and is flexible with respect to choice of source prior and the number of sources and sensors. Inside the engine...

  16. Independent safety organization

    International Nuclear Information System (INIS)

    Kato, W.Y.; Weinstock, E.V.; Carew, J.F.; Cerbone, R.J.; Guppy, J.G.; Hall, R.E.; Taylor, J.H.

    1985-01-01

    Brookhaven National Laboratory has conducted a study on the need and feasibility of an independent organization to investigate significant safety events for the Office for Analysis and Evaluation of Operational Data, USNRC. The study consists of three parts: the need for an independent organization to investigate significant safety events, alternative organizations to conduct investigations, and legislative requirements. The determination of need was investigated by reviewing current NRC investigation practices, comparing aviation and nuclear industry practices, and interviewing a spectrum of representatives from the nuclear industry, the regulatory agency, and the public sector. The advantages and disadvantages of alternative independent organizations were studied, namely, an Office of Nuclear Safety headed by a director reporting to the Executive Director for Operations (EDO) of NRC; an Office of Nuclear Safety headed by a director reporting to the NRC Commissioners; a multi-member NTSB-type Nuclear Safety Board independent of the NRC. The costs associated with operating a Nuclear Safety Board were also included in the study. The legislative requirements, both new authority and changes to the existing NRC legislative authority, were studied. 134 references

  17. Desmin common mutation is associated with multi-systemic disease manifestations and depletion of mitochondria and mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Elizabeth eMcCormick

    2015-06-01

    Full Text Available Desmin (DES is a major muscle scaffolding protein that also functions to anchor mitochondria. Pathogenic DES mutations, however, have not previously been recognized as a cause of multi-systemic mitochondrial disease. Here, we describe a 45-year-old man who presented to The Children’s Hospital of Philadelphia Mitochondrial-Genetics Diagnostic Clinic for evaluation of progressive cardiac, neuromuscular, gastrointestinal, and mood disorders. Muscle biopsy at age 45 was remarkable for cytoplasmic bodies, as well as ragged red fibers and SDH positive/COX negative fibers that were suggestive of a mitochondrial myopathy. Muscle also showed significant reductions in mitochondrial content (16% of control mean for citrate synthase activity and mitochondrial DNA (35% of control mean. His family history was significant for cardiac conduction defects and myopathy in multiple maternal relatives. Multiple single gene and panel-based sequencing studies were unrevealing. Whole exome sequencing identified a known pathogenic p.S13F mutation in DES that had previously been associated with desmin-related myopathy. Desmin-related myopathy is an autosomal dominant disorder characterized by right ventricular hypertrophic cardiomyopathy, myopathy, and arrhythmias. However, neuropathy, gastrointestinal dysfunction, and depletion of both mitochondria and mitochondrial DNA have not previously been widely recognized in this disorder. Recognition that mitochondrial dysfunction occurs in desmin-related myopathy clarifies the basis for the multi-systemic manifestations, as are typical of primary mitochondrial disorders. Understanding the mitochondrial pathophysiology of desmin-related myopathy highlights the possibility of new therapies for the otherwise untreatable and often fatal class of disease. We postulate that drug treatments aimed at improving mitochondrial biogenesis or reducing oxidative stress may be effective therapies to ameliorate the effects of desmin

  18. A permeability transition in liver mitochondria and liposomes induced by α,ω-dioic acids and Ca(2+).

    Science.gov (United States)

    Dubinin, Mikhail V; Samartsev, Victor N; Astashev, Maxim E; Kazakov, Alexey S; Belosludtsev, Konstantin N

    2014-11-01

    The article examines the molecular mechanism of the Ca(2+)-dependent cyclosporin A (CsA)-insensitive permeability transition in rat liver mitochondria induced by α,ω-dioic acids. The addition of α,ω-hexadecanedioic acid (HDA) to Ca(2+)-loaded liver mitochondria was shown to induce a high-amplitude swelling of the organelles, a drop of membrane potential and the release of Ca(2+) from the matrix, the effects being insensitive to CsA. The experiments with liposomes loaded with sulforhodamine B (SRB) revealed that, like palmitic acid (PA), HDA was able to cause permeabilization of liposomal membranes. However, the kinetics of HDA- and PA-induced release of SRB from liposomes was different, and HDA was less effective than PA in the induction of SRB release. Using the method of ultrasound interferometry, we also showed that the addition of Ca(2+) to HDA-containing liposomes did not change the phase state of liposomal membranes-in contrast to what was observed when Ca(2+) was added to PA-containing vesicles. It was suggested that HDA/Ca(2+)- and PA/Ca(2+)-induced permeability transition occurs by different mechanisms. Using the method of dynamic light scattering, we further revealed that the addition of Ca(2+) to HDA-containing liposomes induced their aggregation/fusion. Apparently, these processes result in a partial release of SRB due to the formation of fusion pores. The possibility that this mechanism underlies the HDA/Ca(2+)-induced permeability transition of the mitochondrial membrane is discussed.

  19. Designing inhibitors of cytochrome c/cardiolipin peroxidase complexes: mitochondria-targeted imidazole-substituted fatty acids.

    Science.gov (United States)

    Jiang, Jianfei; Bakan, Ahmet; Kapralov, Alexandr A; Silva, K Ishara; Huang, Zhentai; Amoscato, Andrew A; Peterson, James; Garapati, Venkata Krishna; Saxena, Sunil; Bayir, Hülya; Atkinson, Jeffrey; Bahar, Ivet; Kagan, Valerian E

    2014-06-01

    Mitochondria have emerged as the major regulatory platform responsible for the coordination of numerous metabolic reactions as well as cell death processes, whereby the execution of intrinsic apoptosis includes the production of reactive oxygen species fueling oxidation of cardiolipin (CL) catalyzed by cytochrome (Cyt) c. As this oxidation occurs within the peroxidase complex of Cyt c with CL, the latter represents a promising target for the discovery and design of drugs with antiapoptotic mechanisms of action. In this work, we designed and synthesized a new group of mitochondria-targeted imidazole-substituted analogs of stearic acid TPP-n-ISAs with various positions of the attached imidazole group on the fatty acid (n = 6, 8, 10, 13, and 14). By using a combination of absorption spectroscopy and EPR protocols (continuous wave electron paramagnetic resonance and electron spin echo envelope modulation) we demonstrated that TPP-n-ISAs indeed were able to potently suppress CL-induced structural rearrangements in Cyt c, paving the way to its peroxidase competence. TPP-n-ISA analogs preserved the low-spin hexa-coordinated heme-iron state in Cyt c/CL complexes whereby TPP-6-ISA displayed a significantly more effective preservation pattern than TPP-14-ISA. Elucidation of these intermolecular stabilization mechanisms of Cyt c identified TPP-6-ISA as an effective inhibitor of the peroxidase function of Cyt c/CL complexes with a significant antiapoptotic potential realized in mouse embryonic cells exposed to ionizing irradiation. These experimental findings were detailed and supported by all-atom molecular dynamics simulations. Based on the experimental data and computation predictions, we identified TPP-6-ISA as a candidate drug with optimized antiapoptotic potency. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Natural occurring radioactive substances. Vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Emara, A E [National Center for radiation Research and Technology Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    Naturally occurring radioactive substances produced by cosmic rays of those of terrestrial origin are surveyed. The different radioactive decay series are discussed. Special emphasis is given to the element radium as regards its properties and distribution in different environmental samples. The properties of naturally occurring k-40 and its distribution in different natural media are also outlined. Induced radionuclides which are formed as a result of the interaction of cosmic rays with the constituents of the atmosphere are mentioned. In this respect the intensity of natural background radiation and the dose at different locations and levels is surveyed. Some regions of exceptionally high radioactivity which result in high exposure rates are mentioned. Monazite deposits and water springs are mentioned in some detail. The Oklo phenomenon as a natural reactor is also discussed. 8 tabs.

  1. Natural occurring radioactive substances. Vol. 1

    International Nuclear Information System (INIS)

    Emara, A.E.

    1996-01-01

    Naturally occurring radioactive substances produced by cosmic rays of those of terrestrial origin are surveyed. The different radioactive decay series are discussed. Special emphasis is given to the element radium as regards its properties and distribution in different environmental samples. The properties of naturally occurring k-40 and its distribution in different natural media are also outlined. Induced radionuclides which are formed as a result of the interaction of cosmic rays with the constituents of the atmosphere are mentioned. In this respect the intensity of natural background radiation and the dose at different locations and levels is surveyed. Some regions of exceptionally high radioactivity which result in high exposure rates are mentioned. Monazite deposits and water springs are mentioned in some detail. The Oklo phenomenon as a natural reactor is also discussed. 8 tabs

  2. Jerky Periods - Myoclonus Occurring Solely During Menses

    OpenAIRE

    Arthur W. Buijink; Jeannette M. Gelauff; Sandra M. van der Salm; Marina A. Tijssen; Anne-Fleur van Rootselaar

    2013-01-01

    Background: In this case report, we describe an unusual case of a patient with myoclonus only occurring during menses. Case Report: A 41-year-old female, known to have neurological sequelae after a car accident 1 year earlier, presented with myoclonic movements of the right arm and hand only during menses. Brain magnetic resonance imaging is compatible with head trauma. Electromyography shows brief irregular bursts with a duration of about 20 ms. Discussion: This appears to be the first descr...

  3. Heptachlor induced mitochondria-mediated cell death via impairing electron transport chain complex III

    International Nuclear Information System (INIS)

    Hong, Seokheon; Kim, Joo Yeon; Hwang, Joohyun; Shin, Ki Soon; Kang, Shin Jung

    2013-01-01

    Highlights: •Heptachlor inhibited mitochondrial electron transport chain complex III activity. •Heptachlor promoted generation of reactive oxygen species. •Heptachlor induced Bax activation. •Heptachlor induced mitochondria-mediated and caspase-dependent apoptosis. -- Abstract: Environmental toxins like pesticides have been implicated in the pathogenesis of Parkinson’s disease (PD). Epidemiological studies suggested that exposures to organochlorine pesticides have an association with an increased PD risk. In the present study, we examined the mechanism of toxicity induced by an organochlorine pesticide heptachlor. In a human dopaminergic neuroblastoma SH-SY5Y cells, heptachlor induced both morphological and functional damages in mitochondria. Interestingly, the compound inhibited mitochondrial electron transport chain complex III activity. Rapid generation of reactive oxygen species and the activation of Bax were then detected. Subsequently, mitochondria-mediated, caspase-dependent apoptosis followed. Our results raise a possibility that an organochlorine pesticide heptachlor can act as a neurotoxicant associated with PD

  4. Mitochondria and α-Synuclein: Friends or Foes in the Pathogenesis of Parkinson's Disease?

    Science.gov (United States)

    Faustini, Gaia; Bono, Federica; Valerio, Alessandra; Pizzi, Marina; Spano, PierFranco; Bellucci, Arianna

    2017-12-08

    Parkinson's disease (PD) is a movement disorder characterized by dopaminergic nigrostriatal neuron degeneration and the formation of Lewy bodies (LB), pathological inclusions containing fibrils that are mainly composed of α-synuclein. Dopaminergic neurons, for their intrinsic characteristics, have a high energy demand that relies on the efficiency of the mitochondria respiratory chain. Dysregulations of mitochondria, deriving from alterations of complex I protein or oxidative DNA damage, change the trafficking, size and morphology of these organelles. Of note, these mitochondrial bioenergetics defects have been related to PD. A series of experimental evidence supports that α-synuclein physiological action is relevant for mitochondrial homeostasis, while its pathological aggregation can negatively impinge on mitochondrial function. It thus appears that imbalances in the equilibrium between the reciprocal modulatory action of mitochondria and α-synuclein can contribute to PD onset by inducing neuronal impairment. This review will try to highlight the role of physiological and pathological α-synuclein in the modulation of mitochondrial functions.

  5. Biochemistry, proteomics, and phosphoproteomics of plant mitochondria from non-photosynthetic cells

    DEFF Research Database (Denmark)

    Havelund, Jesper; Thelen, Jay J.; Møller, Ian Max

    2013-01-01

    of mitochondria and general biochemical properties such as oxidative phosphorylation. We will then mention a few adaptive properties in response to water stress, seed maturation and germination and the ability to function under hypoxic conditions. The discussion will mainly focus on Arabidopsis cell cultures......Mitochondria fulfill some basic roles in all plant cells. They supply the cell with energy in the form of ATP and reducing equivalents (NAD(P)H) and they provide the cell with intermediates for a range of biosynthetic pathways. In addition to this, mitochondria contribute to a number of specialized......, etiolated germinating rice seedlings and potato tubers as model plants. It will cover the general proteome as well as the posttranslational modification protein phosphorylation. To date 64 phosphorylated mitochondrial proteins with a total of 103 phosphorylation sites have been identified....

  6. Lateral release of proteins from the TOM complex into the outer membrane of mitochondria.

    Science.gov (United States)

    Harner, Max; Neupert, Walter; Deponte, Marcel

    2011-07-15

    The TOM complex of the outer membrane of mitochondria is the entry gate for the vast majority of precursor proteins that are imported into the mitochondria. It is made up by receptors and a protein conducting channel. Although precursor proteins of all subcompartments of mitochondria use the TOM complex, it is not known whether its channel can only mediate passage across the outer membrane or also lateral release into the outer membrane. To study this, we have generated fusion proteins of GFP and Tim23 which are inserted into the inner membrane and, at the same time, are spanning either the TOM complex or are integrated into the outer membrane. Our results demonstrate that the TOM complex, depending on sequence determinants in the precursors, can act both as a protein conducting pore and as an insertase mediating lateral release into the outer membrane.

  7. Mitochondria and the non-genetic origins of cell-to-cell variability: More is different.

    Science.gov (United States)

    Guantes, Raúl; Díaz-Colunga, Juan; Iborra, Francisco J

    2016-01-01

    Gene expression activity is heterogeneous in a population of isogenic cells. Identifying the molecular basis of this variability will improve our understanding of phenomena like tumor resistance to drugs, virus infection, or cell fate choice. The complexity of the molecular steps and machines involved in transcription and translation could introduce sources of randomness at many levels, but a common constraint to most of these processes is its energy dependence. In eukaryotic cells, most of this energy is provided by mitochondria. A clonal population of cells may show a large variability in the number and functionality of mitochondria. Here, we discuss how differences in the mitochondrial content of each cell contribute to heterogeneity in gene products. Changes in the amount of mitochondria can also entail drastic alterations of a cell's gene expression program, which ultimately leads to phenotypic diversity. Also watch the Video Abstract. © 2015 WILEY Periodicals, Inc.

  8. One-year high fat diet affects muscle-but not brain mitochondria

    DEFF Research Database (Denmark)

    Joergensen, Tenna; Grunnet, Niels; Quistorff, Bjørn

    2015-01-01

    It is well known that few weeks of high fat (HF) diet may induce metabolic disturbances and mitochondrial dysfunction in skeletalmuscle. However, little is known about the effects of long-term HF exposure and effects on brain mitochondria are unknown. Wistarrats were fed either chow (13E% fat......) or HF diet (60E% fat) for 1 year. The HF animals developed obesity, dyslipidemia, insulinresistance, and dysfunction of isolated skeletal muscle mitochondria: state 3 and state 4 were 30% to 50% increased (P .... Adding also succinate in state 3 resulted in ahigher substrate control ratio (SCR) with PC, but a lower SCR with pyruvate (P mitochondria from the same animal showed no changes with the substrates relevant...

  9. Probing cytochrome c in living mitochondria with surface-enhanced Raman spectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A.; Evlyukhin, Andrey B.; Goodilin, Eugene A.

    2015-01-01

    Selective study of the electron transport chain components in living mitochondria is essential for fundamental biophysical research and for the development of new medical diagnostic methods. However, many important details of inter- and intramembrane mitochondrial processes have remained in shadow...... due to the lack of non-invasive techniques. Here we suggest a novel label-free approach based on the surface-enhanced Raman spectroscopy (SERS) to monitor the redox state and conformation of cytochrome c in the electron transport chain in living mitochondria. We demonstrate that SERS spectra of living...... mitochondria placed on hierarchically structured silver-ring substrates provide exclusive information about cytochrome c behavior under modulation of inner mitochondrial membrane potential, proton gradient and the activity of ATP-synthetase. Mathematical simulation explains the observed enhancement of Raman...

  10. Heptachlor induced mitochondria-mediated cell death via impairing electron transport chain complex III

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seokheon; Kim, Joo Yeon; Hwang, Joohyun [Department of Molecular Biology, Sejong University, Seoul 143-747 (Korea, Republic of); Shin, Ki Soon [Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kang, Shin Jung, E-mail: sjkang@sejong.ac.kr [Department of Molecular Biology, Sejong University, Seoul 143-747 (Korea, Republic of)

    2013-08-09

    Highlights: •Heptachlor inhibited mitochondrial electron transport chain complex III activity. •Heptachlor promoted generation of reactive oxygen species. •Heptachlor induced Bax activation. •Heptachlor induced mitochondria-mediated and caspase-dependent apoptosis. -- Abstract: Environmental toxins like pesticides have been implicated in the pathogenesis of Parkinson’s disease (PD). Epidemiological studies suggested that exposures to organochlorine pesticides have an association with an increased PD risk. In the present study, we examined the mechanism of toxicity induced by an organochlorine pesticide heptachlor. In a human dopaminergic neuroblastoma SH-SY5Y cells, heptachlor induced both morphological and functional damages in mitochondria. Interestingly, the compound inhibited mitochondrial electron transport chain complex III activity. Rapid generation of reactive oxygen species and the activation of Bax were then detected. Subsequently, mitochondria-mediated, caspase-dependent apoptosis followed. Our results raise a possibility that an organochlorine pesticide heptachlor can act as a neurotoxicant associated with PD.

  11. ATP synthesis is impaired in isolated mitochondria from myotubes established from type 2 diabetic subjects

    DEFF Research Database (Denmark)

    Minet, Ariane D; Gaster, Michael

    2010-01-01

    To date, it is unknown whether mitochondrial dysfunction in skeletal muscle from subjects with type 2 diabetes is based on primarily reduced mitochondrial mass and/or a primarily decreased mitochondrial ATP synthesis. Mitochondrial mass were determined in myotubes established from eight lean, eight...... mass and the ATP synthesis rate, neither at baseline nor during acute insulin stimulation, were not different between groups. The ratio of ATP synthesis rate at hexokinase versus ATP synthesis rate at baseline was lower in diabetic mitochondria compared to lean mitochondria. Thus the lower content...... obese and eight subjects with type 2 diabetes precultured under normophysiological conditions. Furthermore, mitochondria were isolated and ATP production was measured by luminescence at baseline and during acute insulin stimulation with or without concomitant ATP utilization by hexokinase. Mitochondrial...

  12. [ATP-synthetase activity, respiration and cytochromes of rat heart mitochondria in aging and hyperthyroidism].

    Science.gov (United States)

    Lemeshko, V V; Kaliman, P A; Belostotskaia, L I; Uchitel', A A

    1982-04-01

    The ATP-synthetase activity, the rate of oxygen uptake under different metabolic conditions, the tightness of coupling of respiration to oxidative phosphorylation and the cytochrome contents in heart mitochondria of rats from different age groups were studied under normal conditions and in hyperthyroidism. It was found that heart mitochondria of aged animals did not practically differ in terms of their functional activity from those of the young animals. Administration of thyroxin to the animals from all age groups produced no significant effects on the state of mitochondria, increasing the rate of ATP synthesis on alpha-glycerophosphate, which was especially well-pronounced in aged animals, and the cytochrome content in 1-month-old rats.

  13. Ca(2+)-dependent nonspecific permeability of the inner membrane of liver mitochondria in the guinea fowl (Numida meleagris).

    Science.gov (United States)

    Vedernikov, Aleksander A; Dubinin, Mikhail V; Zabiakin, Vladimir A; Samartsev, Victor N

    2015-06-01

    This comparative study presents the results of the induction of Ca(2+)-dependent nonspecific permeability of the inner membrane (pore opening) of rat and guinea fowl liver mitochondria by mechanisms that are both sensitive and insensitive to cyclosporin A (CsA). It was established that energized rat and guinea fowl liver mitochondria incubated with 1 mM of inorganic phosphate (Pi) are capable of swelling upon addition of at least 125 and 875 nmol of CaCl2 per 1 mg protein, respectively. Under these conditions, the Ca(2+) release from the mitochondria of these animals and a drop in Δψ are observed. All of these processes are inhibited by 1 μM of CsA. FCCP, causing organelle de-energization, induces pore opening in rat and guinea fowl liver mitochondria upon addition of 45 и 625 nmol of CaCl2 per 1 mg protein, respectively. These results suggest the existence of a CsA-sensitive mechanism for the induction of Ca(2+)-dependent pores in guinea fowl liver mitochondria, which has been reported in rat liver mitochondria. However, guinea fowl liver mitochondria have a significantly greater resistance to Ca(2+) as a pore inducer compared to rat liver mitochondria. It was found that the addition of α,ω-hexadecanedioic acid (HDA) to rat and guinea fowl liver mitochondria incubated with CsA and loaded with Ca(2+) causes organelle swelling and Ca(2+) release from the matrix. It is assumed that in contrast to the CsA-sensitive pore, the CsA-insensitive pore induced by HDA in the inner membrane of guinea fowl liver mitochondria, as well as in rat liver mitochondria, is lipid in nature.

  14. Deregulation of Mitochondria-Shaping Proteins Opa-1 and Drp-1 in Manganese-Induced Apoptosis

    Science.gov (United States)

    Alaimo, Agustina; Gorojod, Roxana M.; Beauquis, Juan; Muñoz, Manuel J.; Saravia, Flavia; Kotler, Mónica L.

    2014-01-01

    Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn)-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis. This knowledge may

  15. Deregulation of mitochondria-shaping proteins Opa-1 and Drp-1 in manganese-induced apoptosis.

    Directory of Open Access Journals (Sweden)

    Agustina Alaimo

    Full Text Available Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis

  16. Deregulation of mitochondria-shaping proteins Opa-1 and Drp-1 in manganese-induced apoptosis.

    Science.gov (United States)

    Alaimo, Agustina; Gorojod, Roxana M; Beauquis, Juan; Muñoz, Manuel J; Saravia, Flavia; Kotler, Mónica L

    2014-01-01

    Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn)-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis. This knowledge may

  17. Quantum independent increment processes

    CERN Document Server

    Franz, Uwe

    2005-01-01

    This volume is the first of two volumes containing the revised and completed notes lectures given at the school "Quantum Independent Increment Processes: Structure and Applications to Physics". This school was held at the Alfried-Krupp-Wissenschaftskolleg in Greifswald during the period March 9 – 22, 2003, and supported by the Volkswagen Foundation. The school gave an introduction to current research on quantum independent increment processes aimed at graduate students and non-specialists working in classical and quantum probability, operator algebras, and mathematical physics. The present first volume contains the following lectures: "Lévy Processes in Euclidean Spaces and Groups" by David Applebaum, "Locally Compact Quantum Groups" by Johan Kustermans, "Quantum Stochastic Analysis" by J. Martin Lindsay, and "Dilations, Cocycles and Product Systems" by B.V. Rajarama Bhat.

  18. Quantum independent increment processes

    CERN Document Server

    Franz, Uwe

    2006-01-01

    This is the second of two volumes containing the revised and completed notes of lectures given at the school "Quantum Independent Increment Processes: Structure and Applications to Physics". This school was held at the Alfried-Krupp-Wissenschaftskolleg in Greifswald in March, 2003, and supported by the Volkswagen Foundation. The school gave an introduction to current research on quantum independent increment processes aimed at graduate students and non-specialists working in classical and quantum probability, operator algebras, and mathematical physics. The present second volume contains the following lectures: "Random Walks on Finite Quantum Groups" by Uwe Franz and Rolf Gohm, "Quantum Markov Processes and Applications in Physics" by Burkhard Kümmerer, Classical and Free Infinite Divisibility and Lévy Processes" by Ole E. Barndorff-Nielsen, Steen Thorbjornsen, and "Lévy Processes on Quantum Groups and Dual Groups" by Uwe Franz.

  19. Independent random sampling methods

    CERN Document Server

    Martino, Luca; Míguez, Joaquín

    2018-01-01

    This book systematically addresses the design and analysis of efficient techniques for independent random sampling. Both general-purpose approaches, which can be used to generate samples from arbitrary probability distributions, and tailored techniques, designed to efficiently address common real-world practical problems, are introduced and discussed in detail. In turn, the monograph presents fundamental results and methodologies in the field, elaborating and developing them into the latest techniques. The theory and methods are illustrated with a varied collection of examples, which are discussed in detail in the text and supplemented with ready-to-run computer code. The main problem addressed in the book is how to generate independent random samples from an arbitrary probability distribution with the weakest possible constraints or assumptions in a form suitable for practical implementation. The authors review the fundamental results and methods in the field, address the latest methods, and emphasize the li...

  20. Jerky periods: myoclonus occurring solely during menses.

    Science.gov (United States)

    Buijink, Arthur W G; Gelauff, Jeannette M; van der Salm, Sandra M A; Tijssen, Marina A J; van Rootselaar, Anne-Fleur

    2013-01-01

    In this case report, we describe an unusual case of a patient with myoclonus only occurring during menses. A 41-year-old female, known to have neurological sequelae after a car accident 1 year earlier, presented with myoclonic movements of the right arm and hand only during menses. Brain magnetic resonance imaging is compatible with head trauma. Electromyography shows brief irregular bursts with a duration of about 20 ms. This appears to be the first description of myoclonus appearing only during menses. We suggest a cortical origin for myoclonus.

  1. Jerky Periods - Myoclonus Occurring Solely During Menses

    Directory of Open Access Journals (Sweden)

    Arthur W. Buijink

    2013-05-01

    Full Text Available Background: In this case report, we describe an unusual case of a patient with myoclonus only occurring during menses. Case Report: A 41-year-old female, known to have neurological sequelae after a car accident 1 year earlier, presented with myoclonic movements of the right arm and hand only during menses. Brain magnetic resonance imaging is compatible with head trauma. Electromyography shows brief irregular bursts with a duration of about 20 ms. Discussion: This appears to be the first description of myoclonus appearing only during menses. We suggest a cortical origin for myoclonus.

  2. [Features of noradrenaline stimulation of rat liver mitochondria respiration by ADP and calcium ions].

    Science.gov (United States)

    Stefankiv, Iu S; Babskyĭ, A M; Shostakovska, Y V

    1995-01-01

    A single administration of a physiological dose of noradrenaline to animals. in contrast to adrenaline, stimulates the respiration of mitochondria not only under oxidation of FAD-dependent Krebbs cycle substrate of the succinase but also HAD-dependent substrate of alpha-ketoglutarate. In the both cases the phosphorylation rate increases, since the action of noradrenaline, separating the respiration and oxidative phosphorylation, was not found. Noradrenaline increases the capacity of mitochondria to more actively absorb calcium ions under oxidation of succinate than under that of alpha-ketoglutarate.

  3. The peroxisome-mitochondria connection : identification and characterization of novel membrane proteins shared by both organelles

    OpenAIRE

    Castro, Inês Gomes de Oliveira e

    2011-01-01

    Dissertação de mestrado em Biologia Celular e Molecular apresentada ao Departamento Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra. Peroxisomes and mitochondria are known to act in concert, sharing a growing number of proteins and cellular functions. This connection includes metabolic cooperations and cross-talk (e.g. in fatty acid β-oxidation), a novel putative vesicular trafficking pathway from mitochondria to peroxisomes, an overlap in key components o...

  4. The effect of amixin and agmatine on cytochrome c release from isolated mitochondria

    Directory of Open Access Journals (Sweden)

    K. R. Uspenska

    2017-02-01

    Full Text Available Mitochondrial nicotinic acetylcholine receptors (nAChRs control permeability transition pore formation and cytochrome c release in the presence of apoptogenic factors. This study demonstrates that pharmacological agents amixin and agmatine affect mitochondrial nAChR functioning: they slightly suppress cytochrome c release from mouse brain and liver mitochondria stimulated with apoptogenic dose of Са2+ and prevent the effect of α7 nAChR agonist PNU282987. We conclude that mitochondria may be one of therapeutic targets of amixin and agmatine.

  5. Binding of in vivo administrated 125-I-triiodothyronine by the rat liver mitochondria

    International Nuclear Information System (INIS)

    Fiedorowicz, K.; Nauman, A.; Nauman, J.

    1979-01-01

    In vivo administrated 125 I-triiodothyronine ( 125 I-T 3 ) was bound by the rat liver mitochondria. About 10 % of hormone was bound with external mitochondrial membrane while the remaining part with matrix and inner mitochondrial membrane. The highest accumulation of 125 I-T 3 in mitochondria was observed 30 min after injection while in the whole liver homogenate the highest hormone accumulation appeared 15 min post injection. Mitochondrial binding sites have a great capacity for T 3 which makes impossible estimation of the kinetic parameters of triiodothyronine-mitochondrium interaction by means of saturation and displacement of 125 I-T 3 . (author)

  6. Electron transfer and photophosphorylation in mitochondria of buckwheat after irradiation of seeds with. gamma. -rays

    Energy Technology Data Exchange (ETDEWEB)

    Guseva, V A; Kurganova, L N; Gorlanova, T M [Gor' kovskij Gosudarstvennyj Univ. (USSR)

    1974-11-01

    Pre-sowing irradiation of seeds at 500 R activates the transfer of electrons by photosynthetic electron transfer path of isolated buchwheat chloroplasts in the ontogenesis and stimulates the conjugated photosynthetic phosphorilation. An increased content of NADPxH/sub 2/ is observed along with an elevated level of ATP production. Intensification of oxidative phosphorilation and growth of the P/O ratio of mitochondria has been shown in the ''irradiated'' plants, together with a concomitant increase of ATPhase activity in chloroplasts and mitochondria.

  7. Chlamydomonas reinhardtii: the model of choice to study mitochondria from unicellular photosynthetic organisms.

    Science.gov (United States)

    Funes, Soledad; Franzén, Lars-Gunnar; González-Halphen, Diego

    2007-01-01

    Chlamydomonas reinhardtii is a model organism to study photosynthesis, cellular division, flagellar biogenesis, and, more recently, mitochondrial function. It has distinct advantages in comparison to higher plants because it is unicellular, haploid, and amenable to tetrad analysis, and its three genomes are subject to specific transformation. It also has the possibility to grow either photoautotrophically or heterotrophically on acetate, making the assembly of the photosynthetic machinery not essential for cell viability. Methods developed allow the isolation of C. reinhardtii mitochondria free of thylakoid contaminants. We review the general procedures used for the biochemical characterization of mitochondria from this green alga.

  8. Inhibition of ATP synthesis by fenbufen and its conjugated metabolites in rat liver mitochondria

    DEFF Research Database (Denmark)

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2016-01-01

    in the drug induced liver injury (DILI) by fenbufen, the inhibitory effect of fenbufen and its conjugated metabolites on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria was investigated. Fenbufen glucuronide (F-GlcA), fenbufen-N-acetyl cysteine-thioester (F-NAC) and fenbufen...... and fenbufen show any protective effect on fenbufen mediated inhibition of oxidative phosphorylation. Inclusion of NADPH in mitochondrial preparations with fenbufen did not modulate the inhibitory effects, suggesting no role of CYP mediated oxidative metabolites on the ATP synthesis in isolated mitochondria...

  9. International exploration by independents

    International Nuclear Information System (INIS)

    Bertagne, R.G.

    1991-01-01

    Recent industry trends indicate that the smaller US independents are looking at foreign exploration opportunities as one of the alternatives for growth in the new age of exploration. It is usually accepted that foreign finding costs per barrel are substantially lower than domestic because of the large reserve potential of international plays. To get involved overseas requires, however, an adaptation to different cultural, financial, legal, operational, and political conditions. Generally foreign exploration proceeds at a slower pace than domestic because concessions are granted by the government, or are explored in partnership with the national oil company. First, a mid- to long-term strategy, tailored to the goals and the financial capabilities of the company, must be prepared; it must be followed by an ongoing evaluation of quality prospects in various sedimentary basins, and a careful planning and conduct of the operations. To successfully explore overseas also requires the presence on the team of a minimum number of explorationists and engineers thoroughly familiar with the various exploratory and operational aspects of foreign work, having had a considerable amount of onsite experience in various geographical and climatic environments. Independents that are best suited for foreign expansion are those that have been financially successful domestically, and have a good discovery track record. When properly approached foreign exploration is well within the reach of smaller US independents and presents essentially no greater risk than domestic exploration; the reward, however, can be much larger and can catapult the company into the big leagues

  10. International exploration by independent

    International Nuclear Information System (INIS)

    Bertragne, R.G.

    1992-01-01

    Recent industry trends indicate that the smaller U.S. independents are looking at foreign exploration opportunities as one of the alternatives for growth in the new age of exploration. Foreign finding costs per barrel usually are accepted to be substantially lower than domestic costs because of the large reserve potential of international plays. To get involved in overseas exploration, however, requires the explorationist to adapt to different cultural, financial, legal, operational, and political conditions. Generally, foreign exploration proceeds at a slower pace than domestic exploration because concessions are granted by a country's government, or are explored in partnership with a national oil company. First, the explorationist must prepare a mid- to long-term strategy, tailored to the goals and the financial capabilities of the company; next, is an ongoing evaluation of quality prospects in various sedimentary basins, and careful planning and conduct of the operations. To successfully explore overseas also requires the presence of a minimum number of explorationists and engineers thoroughly familiar with the various exploratory and operational aspects of foreign work. Ideally, these team members will have had a considerable amount of on-site experience in various countries and climates. Independents best suited for foreign expansion are those who have been financially successful in domestic exploration. When properly approached, foreign exploration is well within the reach of smaller U.S. independents, and presents essentially no greater risk than domestic exploration; however, the reward can be much larger and can catapult the company into the 'big leagues.'

  11. Agent independent task planning

    Science.gov (United States)

    Davis, William S.

    1990-01-01

    Agent-Independent Planning is a technique that allows the construction of activity plans without regard to the agent that will perform them. Once generated, a plan is then validated and translated into instructions for a particular agent, whether a robot, crewmember, or software-based control system. Because Space Station Freedom (SSF) is planned for orbital operations for approximately thirty years, it will almost certainly experience numerous enhancements and upgrades, including upgrades in robotic manipulators. Agent-Independent Planning provides the capability to construct plans for SSF operations, independent of specific robotic systems, by combining techniques of object oriented modeling, nonlinear planning and temporal logic. Since a plan is validated using the physical and functional models of a particular agent, new robotic systems can be developed and integrated with existing operations in a robust manner. This technique also provides the capability to generate plans for crewmembers with varying skill levels, and later apply these same plans to more sophisticated robotic manipulators made available by evolutions in technology.

  12. International exploration by independents

    International Nuclear Information System (INIS)

    Bertagne, R.G.

    1992-01-01

    Recent industry trends indicate that the smaller U.S. independents are looking at foreign exploration opportunities as one of the alternatives for growth in the new age of exploration. The problems of communications and logistics caused by different cultures and by geographic distances must be carefully evaluated. A mid-term to long-term strategy tailored to the goals and the financial capabilities of the company should be prepared and followed by a careful planning of the operations. This paper addresses some aspects of foreign exploration that should be considered before an independent venture into the foreign field. It also provides some guidelines for conducting successful overseas operations. When properly assessed, foreign exploration is well within the reach of smaller U.S. independents and presents no greater risk than domestic exploration; the rewards, however, can be much larger. Furthermore, the Oil and Gas Journal surveys of the 300 largest U.S. petroleum companies show that companies with a consistent foreign exploration policy have fared better financially during difficult times

  13. Leachability of naturally occurring radioactive materials

    International Nuclear Information System (INIS)

    Desideri, D.; Feduzi, L.; Meli, M.A.; Roselli, C.

    2006-01-01

    Naturally occurring radioactive materials (NORM) are present in the environment and can be concentrated by technical activities, particularly those involving natural resources. These NORM deposits are highly stable and very insoluble under environmental conditions at the earth's surface. However, reducing or oxidant conditions or pH changes may enable a fraction of naturally occurring radionuclides to eventually be released to the environment. Leachability of 210 Pb and 210 Po was determined in three samples coming from a refractories production plant (dust, sludge, finished product), in one dust sample from a steelwork and in one ash sample coming from an electric power station. A sequential extraction method consisting of five operationally-defined fractions was used. The average leaching potential observed in the samples from the refractory industry is very low (mean values: 5.8% for 210 Pb and 1.7% for 210 Po). The 210 Pb and 210 Po leachability increases for the ash sample coming from an electric power plant using carbon (17.8% for 210 Pb and 10.0% for 210 Po); for the dust sample coming from a steelwork, the percent soluble fraction is 41.1% for 210 Pb and 8.5% for 210 Po. For all samples the results obtained show that 210 Pb is slightly more soluble than 210 Po. (author)

  14. Carbon monoxide improves neuronal differentiation and yield by increasing the functioning and number of mitochondria.

    Science.gov (United States)

    Almeida, Ana S; Sonnewald, Ursula; Alves, Paula M; Vieira, Helena L A

    2016-08-01

    The process of cell differentiation goes hand-in-hand with metabolic adaptations, which are needed to provide energy and new metabolites. Carbon monoxide (CO) is an endogenous cytoprotective molecule able to inhibit cell death and improve mitochondrial metabolism. Neuronal differentiation processes were studied using the NT2 cell line, which is derived from human testicular embryonic teratocarcinoma and differentiates into post-mitotic neurons upon retinoic acid treatment. CO-releasing molecule A1 (CORM-A1) was used do deliver CO into cell culture. CO treatment improved NT2 neuronal differentiation and yield, since there were more neurons and the total cell number increased following the differentiation process. CO supplementation enhanced the mitochondrial population in post-mitotic neurons derived from NT2 cells, as indicated by an increase in mitochondrial DNA. CO treatment during neuronal differentiation increased the extent of the classical metabolic change that occurs during neuronal differentiation, from glycolytic to more oxidative metabolism, by decreasing the ratio of lactate production and glucose consumption. The expression of pyruvate and lactate dehydrogenases was higher, indicating an augmented oxidative metabolism. Moreover, these findings were corroborated by an increased percentage of (13) C incorporation from [U-(13) C]glucose into the tricarboxylic acid cycle metabolites malate and citrate, and also glutamate and aspartate in CO-treated cells. Finally, under low levels of oxygen (5%), which enhances glycolytic metabolism, some of the enhancing effects of CO on mitochondria were not observed. In conclusion, our data show that CO improves neuronal and mitochondrial yield by stimulation of tricarboxylic acid cycle activity, and thus oxidative metabolism of NT2 cells during the process of neuronal differentiation. The process of cell differentiation is coupled with metabolic adaptations. Carbon monoxide (CO) is an endogenous cytoprotective

  15. Identification of the site where the electron transfer chain of plant mitochondria is stimulated by electrostatic charge screening.

    NARCIS (Netherlands)

    Krab, K.; Wagner, M.J.; Wagner, A.M.; Moller, I.M.

    2000-01-01

    Modular kinetic analysis was used to determine the sites in plant mitochondria where charge-screening stimulates the rate of electron transfer from external NAD(P)H to oxygen. In mitochondria isolated from potato (Solanum tuberosum L.) tuber callus, stimulation of the rate of oxygen uptake was

  16. A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

    International Nuclear Information System (INIS)

    Park, So Jung; Park, Young Jun; Shin, Ji Hyun; Kim, Eun Sung; Hwang, Jung Jin; Jin, Dong-Hoon; Kim, Jin Cheon; Cho, Dong-Hyung

    2011-01-01

    Highlights: → We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. → Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. → Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. → Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactive chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.

  17. Comparative studies on mitochondria isolated from neuron-enriched and glia-enriched fractions of rabbit and beef brain.

    Science.gov (United States)

    Hamberger, A; Blomstrand, C; Lehninger, A L

    1970-05-01

    Fractions enriched in neuronal and glial cells were obtained from dispersions of whole beef brain and rabbit cerebral cortex by large-scale density gradient centrifugation procedures. The fractions were characterized by appropriate microscopic observation. Mitochondria were then isolated from these fractions by differential centrifugation of their homogenates. The two different types of mitochondria were characterized with respect to certain enzyme activities, respiratory rate, rate of protein synthesis, and their buoyant density in sucrose gradients. The mitochondria from the neuron-enriched fraction were distinguished by a higher rate of incorporation of amino acids into protein, higher cytochrome oxidase activity, and a higher buoyant density in sucrose density gradients. Mitochondria from the glia-enriched fraction showed relatively high monoamine oxidase and Na(+)- and K(+)-stimulated ATPase activities. The rates of oxidation of various substrates and the acceptor control ratios did not differ appreciably between the two types of mitochondria. The difference in the buoyant density of mitochondria isolated from the neuron-enriched and glia-enriched cell fractions was utilized in attempts to separate neuronal and glial mitochondria from the mixed mitochondria obtained from whole brain homogenates in shallow sucrose gradients. The appearance of two peaks of cytochrome oxidase, monoamine oxidase, and protein concentration in such gradients shows the potential feasibility of such an approach.

  18. Organelle-cytoskeleton relationships in fibroblasts: mitochondria, Golgi apparatus, and endoplasmic reticulum in phases of movement and growth

    DEFF Research Database (Denmark)

    Couchman, J R; Rees, D A

    1982-01-01

    When fibroblasts first emerge from explants of embryonic chick heart, most mitochondria are clustered tightly around the nucleus, with very few extending towards the leading lamella. Although cytoplasmic microtubules are well displayed, mitochondria do not obviously codistribute with them. As the...

  19. Possible role of non-bilayer lipids in the structure of mitochondria. A freeze-fracture electron microscopy study

    NARCIS (Netherlands)

    Venetie, R. van; Verkleij, A.J.

    1982-01-01

    The possible role of non-bilayer phospholipids on the structure of isolated rat liver mitochondria has been morphologically studied. Freshly isolated freeze-fractured mitochondria show smooth fracture faces with particles, representing the limiting membranes. The frequency and size of the particles

  20. Wegener's granulomatosis occurring de novo during pregnancy.

    Science.gov (United States)

    Alfhaily, F; Watts, R; Leather, A

    2009-01-01

    Wegener's granulomatosis (WG) is rarely diagnosed during the reproductive years and uncommonly manifests for the first time during pregnancy. We report a case of de novo WG presenting at 30 weeks gestation with classical symptoms of WG (ENT, pulmonary). The diagnosis was confirmed by radiological, laboratory, and histological investigations. With a multidisciplinary approach, she had a successful vaginal delivery of a healthy baby. She was treated successfully by a combination of steroids, azathioprine and intravenous immunoglobulin in the active phase of disease for induction of remission and by azathioprine and steroids for maintenance of remission. The significant improvement in her symptoms allowed us to continue her pregnancy to 37 weeks when delivery was electively induced. Transplacental transmission of PR3-ANCA occurred but the neonate remained well. This case of de novo WG during pregnancy highlights the seriousness of this disease and the challenge in management of such patients.

  1. Lupeol induces S-phase arrest and mitochondria-mediated ...

    Indian Academy of Sciences (India)

    Nupoor Prasad

    2018-03-22

    Mar 22, 2018 ... 99% of cervical cancer occurs due to infection with HPV-16 .... the culture medium, which was found non-toxic to the cells. .... containing 5% non-fat milk for 1 h at room temperature or ..... and inactivate them (Hinds 2003).

  2. Formation and utilization of acetoin, an unusual product of pyruvate metabolism by Ehrlich and AS30-D tumor mitochondria.

    Science.gov (United States)

    Baggetto, L G; Lehninger, A L

    1987-07-15

    [14C]Pyruvate was rapidly non-oxidatively decarboxylated by Ehrlich tumor mitochondria at a rate of 40 nmol/min/mg of protein in the presence or absence of ADP. A search for decarboxylation products led to significant amounts of acetoin formed when Ehrlich tumor mitochondria were incubated with 1 mM [14C] pyruvate in the presence of ATP. Added acetoin to aerobic tumor mitochondria was rapidly utilized in the presence of ATP at a rate of 65 nmol/min/mg of protein. Citrate has been found as a product of acetoin utilization and was exported from the tumor mitochondria. Acetoin has been found in the ascitic liquid of Ehrlich and AS30-D tumor-bearing animals. These unusual reactions were not observed in control rat liver mitochondria.

  3. Independence in appearance

    DEFF Research Database (Denmark)

    Warming-Rasmussen, Bent; Quick, Reiner; Liempd, Dennis van

    2011-01-01

    In the wake of the financial crisis, the EU Commission has published a Green Paper on the future role of the audit function in Europe. The Green Paper lists a number of proposals for tighter rules for audits and auditors in order to contribute to stabilizing the financial system. The present...... article presents research contributions to the question whether the auditor is to continue to provide both audit and non-audit services (NAS) to an audit client. Research results show that this double function for the same audit client is a problem for stakeholders' confidence in auditor independence...

  4. Unique hepatic cytosolic arginase evolved independently in ureogenic freshwater air-breathing teleost, Heteropneustes fossilis.

    Directory of Open Access Journals (Sweden)

    Shilpee Srivastava

    Full Text Available Hepatic cytosolic arginase (ARG I, an enzyme of the urea cycle operating in the liver of ureotelic animals, is reported to be present in an ammoniotelic freshwater air-breathing teleost, Heteropneustes fossilis which has ureogenic potential. Antibodies available against mammalian ARG I showed no cross reactivity with the H. fossilis ARG I. We purified unique ARG I from H. fossilis liver. Purified ARG I is a homotrimer with molecular mass 75 kDa and subunit molecular mass of 24 kDa. The pI value of the enzyme was 8.5. It showed maximum activity at pH 10.5 and 55°C. The Km of purified enzyme for L-arginine was 2.65±0.39 mM. L-ornithine and N(ω-hydroxy-L-arginine showed inhibition of the ARG I activity, with Ki values 0.52±0.02mM and 0.08±0.006mM, respectively. Antibody raised against the purified fish liver ARG I showed exclusive specificity, and has no cross reactivity against fish liver ARG II and mammalian liver ARG I and ARG II. We found another isoform of arginase bound to the outer membrane of the mitochondria which was released by 150-200 mM KCl in the extraction medium. This isoform was immunologically different from the soluble cytosolic and mitochondrial arginase. The results of present study support that hepatic cytosolic arginase evolved in this ureogenic freshwater teleost, H. fossilis. Phylogenetic analysis confirms an independent evolution event that occurred much after the evolution of the cytosolic arginase of ureotelic vertebrates.

  5. Naturally occurring, tumor-specific, therapeutic proteins.

    Science.gov (United States)

    Argiris, Konstantinos; Panethymitaki, Chrysoula; Tavassoli, Mahvash

    2011-05-01

    The emerging approach to cancer treatment known as targeted therapies offers hope in improving the treatment of therapy-resistant cancers. Recent understanding of the molecular pathogenesis of cancer has led to the development of targeted novel drugs such as monoclonal antibodies, small molecule inhibitors, mimetics, antisense and small interference RNA-based strategies, among others. These compounds act on specific targets that are believed to contribute to the development and progression of cancers and resistance of tumors to conventional therapies. Delivered individually or combined with chemo- and/or radiotherapy, such novel drugs have produced significant responses in certain types of cancer. Among the most successful novel compounds are those which target tyrosine kinases (imatinib, trastuzumab, sinutinib, cetuximab). However, these compounds can cause severe side-effects as they inhibit pathways such as epidermal growth factor receptor (EGFR) or platelet-derived growth factor receptor, which are also important for normal functions in non-transformed cells. Recently, a number of proteins have been identified which show a remarkable tumor-specific cytotoxic activity. This toxicity is independent of tumor type or specific genetic changes such as p53, pRB or EGFR aberrations. These tumor-specific killer proteins are either derived from common human and animal viruses such as E1A, E4ORF4 and VP3 (apoptin) or of cellular origin, such as TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) and MDA-7 (melanoma differentiation associated-7). This review aims to present a current overview of a selection of these proteins with preferential toxicity among cancer cells and will provide an insight into the possible mechanism of action, tumor specificity and their potential as novel tumor-specific cancer therapeutics.

  6. Introduction to naturally occurring radioactive material

    International Nuclear Information System (INIS)

    Egidi, P.

    1997-01-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. Some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose-based standards. So when is TENORM a problem? Where is it a problem? That depends on when, where, and whom you talk to exclamation point We will start by reviewing background radioactivity, then we will proceed to the geology, mobility, and variability of these

  7. Introduction to naturally occurring radioactive material

    Energy Technology Data Exchange (ETDEWEB)

    Egidi, P.

    1997-08-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose

  8. Association between ROS production, swelling and the respirasome integrity in cardiac mitochondria.

    Science.gov (United States)

    Jang, Sehwan; Javadov, Sabzali

    2017-09-15

    Although mitochondrial Ca 2+ overload and ROS production play a critical role in mitochondria-mediated cell death, a cause-effect relationship between them remains elusive. This study elucidated the crosstalk between mitochondrial swelling, ROS production, and electron transfer chain (ETC) supercomplexes in rat heart mitochondria in response to Ca 2+ and tert-butyl hydroperoxide (TBH), a lipid-soluble organic peroxide. Results showed that ROS production induced by TBH was significantly increased in the presence of Ca 2+ in a dose-dependent manner. TBH markedly inhibited the state 3 respiration rate with no effect on the mitochondrial swelling. Ca 2+ exerted a slight effect on mitochondrial respiration that was greatly aggravated by TBH. Analysis of supercomplexes revealed a minor difference in the presence of TBH and/or Ca 2+ . However, incubation of mitochondria in the presence of high Ca 2+ (1 mM) or inhibitors of ETC complexes (rotenone and antimycin A) induced disintegration of the main supercomplex, respirasome. Thus, PTP-dependent swelling of mitochondria solely depends on Ca 2+ but not ROS. TBH has no effect on the respirasome while Ca 2+ induces disintegration of the supercomplex only at a high concentration. Intactness of individual ETC complexes I and III is important for maintenance of the structural integrity of the respirasome. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. A structured approach to the study of metabolic control principles in intact and impaired mitochondria.

    Science.gov (United States)

    Huber, Heinrich J; Connolly, Niamh M C; Dussmann, Heiko; Prehn, Jochen H M

    2012-03-01

    We devised an approach to extract control principles of cellular bioenergetics for intact and impaired mitochondria from ODE-based models and applied it to a recently established bioenergetic model of cancer cells. The approach used two methods for varying ODE model parameters to determine those model components that, either alone or in combination with other components, most decisively regulated bioenergetic state variables. We found that, while polarisation of the mitochondrial membrane potential (ΔΨ(m)) and, therefore, the protomotive force were critically determined by respiratory complex I activity in healthy mitochondria, complex III activity was dominant for ΔΨ(m) during conditions of cytochrome-c deficiency. As a further important result, cellular bioenergetics in healthy, ATP-producing mitochondria was regulated by three parameter clusters that describe (1) mitochondrial respiration, (2) ATP production and consumption and (3) coupling of ATP-production and respiration. These parameter clusters resembled metabolic blocks and their intermediaries from top-down control analyses. However, parameter clusters changed significantly when cells changed from low to high ATP levels or when mitochondria were considered to be impaired by loss of cytochrome-c. This change suggests that the assumption of static metabolic blocks by conventional top-down control analyses is not valid under these conditions. Our approach is complementary to both ODE and top-down control analysis approaches and allows a better insight into cellular bioenergetics and its pathological alterations.

  10. The free NADH concentration is kept constant in plant mitochondria under different metabolic conditions

    DEFF Research Database (Denmark)

    Kasimova, M.R.; Grigiene, J.; Krab, K.

    2006-01-01

    with fluorescence spectroscopy. The NADH content of actively respiring mitochondria (from potato tubers [Solanum tuberosum cv Bintje]) in different metabolic states was then measured by spectral decomposition analysis of fluorescence emission spectra. Most of the mitochondrial NADH is bound to proteins...... metabolism. These findings have far-reaching consequences for the interpretation of cellular metabolism....

  11. Discovery of a new mitochondria permeability transition pore (mPTP) inhibitor based on gallic acid.

    Science.gov (United States)

    Teixeira, José; Oliveira, Catarina; Cagide, Fernando; Amorim, Ricardo; Garrido, Jorge; Borges, Fernanda; Oliveira, Paulo J

    2018-12-01

    Pharmacological interventions targeting mitochondria present several barriers for a complete efficacy. Therefore, a new mitochondriotropic antioxidant (AntiOxBEN 3 ) based on the dietary antioxidant gallic acid was developed. AntiOxBEN 3 accumulated several thousand-fold inside isolated rat liver mitochondria, without causing disruption of the oxidative phosphorylation apparatus, as seen by the unchanged respiratory control ratio, phosphorylation efficiency, and transmembrane electric potential. AntiOxBEN 3 showed also limited toxicity on human hepatocarcinoma cells. Moreover, AntiOxBEN 3 presented robust iron-chelation and antioxidant properties in both isolated liver mitochondria and cultured rat and human cell lines. Along with its low toxicity profile and high antioxidant activity, AntiOxBEN 3 strongly inhibited the calcium-dependent mitochondrial permeability transition pore (mPTP) opening. From our data, AntiOxBEN 3 can be considered as a lead compound for the development of a new class of mPTP inhibitors and be used as mPTP de-sensitiser for basic research or clinical applications or emerge as a therapeutic application in mitochondria dysfunction-related disorders.

  12. Acrolein-induced cell death in PC12 cells: role of mitochondria-mediated oxidative stress.

    Science.gov (United States)

    Luo, Jian; Robinson, J Paul; Shi, Riyi

    2005-12-01

    Oxidative stress has been implicated in acrolein cytotoxicity in various cell types, including mammalian spinal cord tissue. In this study we report that acrolein also decreases PC12 cell viability in a reactive oxygen species (ROS)-dependent manner. Specifically, acrolein-induced cell death, mainly necrosis, is accompanied by the accumulation of cellular ROS. Elevating ROS scavengers can alleviate acrolein-induced cell death. Furthermore, we show that exposure to acrolein leads to mitochondrial dysfunction, denoted by the loss of mitochondrial transmembrane potential, reduction of cellular oxygen consumption, and decrease of ATP level. This raises the possibility that the cellular accumulation of ROS could result from the increased production of ROS in the mitochondria of PC12 cells as a result of exposure to acrolein. The acrolein-induced significant decrease of ATP production in mitochondria may also explain why necrosis, not apoptosis, is the dominant type of cell death. In conclusion, our data suggest that one possible mechanism of acrolein-induced cell death could be through mitochondria as its initial target. The subsequent increase of ROS then inflicts cell death and further worsens mitochondria function. Such mechanism may play an important role in CNS trauma and neurodegenerative diseases.

  13. Mitochondria as a Possible Place for Initial Stages of Steroid Biosynthesis in Plants

    Directory of Open Access Journals (Sweden)

    Elena K. Shematorova

    2014-12-01

    Full Text Available With the aim of thorough comparison of steroidogenic systems of plants and animals, transgenic plants of Solanaceae family expressing CYP11A1 cDNA encoding cytochrome P450SCC of mammalian mitochondria were further analysed. Positive effect of CYP11A1 on resistance of the transgenic tobacco plants to the infection by fungal phytopathogene Botrytis cinerea was for the first time detected. Subtle changes in mitochondria of the transgenic Nicotiana tabacum plants expressing mammalian CYP11A1 cDNA were demonstrated by transmissive electron microscopy. The main components of the electron transfer chain of plant mitochondria were for the first time cloned and characterized. It was established that plants from the Solanacea family (tomato, tobacco and potato contain two different genes with similar exon-intron structures (all contain 8 exons encoding mitochondrial type ferredoxins (MFDX, and one gene for mitochondrial ferredoxin reductase (MFDXR. The results obtained point out on profound relatedness of electron transfer chains of P450-dependent monooxygenases in mammalian and plant mitochondria and support our previous findings about functional compatability of steroidogenic systems of Plantae and Animalia.

  14. New method of plant mitochondria isolation and sub-fractionation for proteomic analyses

    Czech Academy of Sciences Publication Activity Database

    Hájek, Tomáš; Honys, David; Čapková, Věra

    2004-01-01

    Roč. 167, č. 3 (2004), s. 389-395 ISSN 0168-9452 R&D Projects: GA MŠk LZ1K03018 Institutional research plan: CEZ:AV0Z5038910 Keywords : plant mitochondria isolation * sub-fractionation * protein analysis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.389, year: 2004

  15. Biochemistry, proteomics and phosphoproteomics of plant mitochondria from non-photosynthetic cells

    Directory of Open Access Journals (Sweden)

    Jesper Foged Havelund

    2013-03-01

    Full Text Available Mitochondria fulfill some basic roles in all plant cells. They supply the cell with energy in the form of ATP and reducing equivalents (NAD(PH and they provide the cell with intermediates for a range of biosynthetic pathways. In addition to this, mitochondria contribute to a number of specialized functions depending on the tissue and cell type, as well as environmental conditions. We will here review the biochemistry and proteomics of mitochondria from non-green cells and organs, which differ from those of photosynthetic organs in a number of respects. We will briefly cover purification of mitochondria and general biochemical properties such as oxidative phosphorylation. We will then mention a few adaptive properties in response to water stress, seed maturation and germination and the ability to function under hypoxic conditions. The discussion will mainly focus on Arabidopsis cell cultures, etiolated germinating rice seedlings and potato tubers as model plants. It will cover the general proteome as well as the posttranslational modification protein phosphorylation. To date 64 phosphorylated mitochondrial proteins with a total of 103 phosphorylation sites have been identified.

  16. What cost mitochondria? The maintenance of functional mitochondrial DNA within and across generations

    NARCIS (Netherlands)

    Aanen, D.K.; Spelbrink, J.N.; Beekman, M.

    2014-01-01

    The peculiar biology of mitochondrial DNA (mtDNA) potentially has detrimental consequences for organismal health and lifespan. Typically, eukaryotic cells contain multiple mitochondria, each with multiple mtDNA genomes. The high copy number of mtDNA implies that selection on mtDNA functionality is

  17. Quantitative control of mitochondria transfer between live single cells using a microfluidic device

    Directory of Open Access Journals (Sweden)

    Ken-Ichi Wada

    2017-12-01

    Full Text Available Quantitative control of mitochondria transfer between live cells is a promising approach for genetic manipulation of mitochondrial DNA (mtDNA because single mitochondrion transfer to a mtDNA-less (ρ0 cell potentially leads to homoplasmy of mtDNA. In this paper, we describe a method for quantitative control of mitochondria transfer between live single cells. For this purpose, we fabricated novel microfluidic devices having cell paring structures with a 4.1, 5.6 or 10.0 μm-length microtunnel. When cells were fused through a microtunnel using the Sendai virus envelope-based method, a strictured cytoplasmic connection was achieved with a length corresponding to that of the microtunnel. Elongation of the cytoplasmic connection led to a decrease in mitochondria transfer to the fusion partner. Moreover, some cell pairs that fused through a 10.0 μm-length microtunnel showed single mitochondrion transfer. Fused cells were spontaneously disconnected from each other when they were recovered in a normal culture medium. These results suggest that our cell fusion method can perform quantitative control of mitochondria transfer that includes a single mitochondrion transfer.

  18. Toxic effects of carvacrol, caryophyllene oxide, and ascaridole from essential oil of Chenopodium ambrosioides on mitochondria

    International Nuclear Information System (INIS)

    Monzote, Lianet; Stamberg, Werner; Staniek, Katrin; Gille, Lars

    2009-01-01

    Chenopodium ambrosioides have been used for centuries in the Americas as a popular remedy for parasitic diseases. The essential oil of this plant possesses anthelmintic activity and is still used in some regions to treat parasitosis and leishmaniasis. However, the Chenopodium oil caused also some fatalities, leading to its commercial disuse. In this work, we studied the mechanism of toxicity of the essential oil and its major pure ingredients (carvacrol, caryophyllene oxide, and ascaridole, which was synthesized from α-terpinene) with respect to mammalian cells and mitochondria. We observed that all products, but especially caryophyllene oxide, inhibited the mitochondrial electron transport chain. This effect for carvacrol and caryophyllene oxide was mediated via direct complex I inhibition. Without Fe 2+ , ascaridole was less toxic to mammalian mitochondria than other major ingredients. However, evidence on the formation of carbon-centered radicals in the presence of Fe 2+ was obtained by ESR spin-trapping. Furthermore, it was shown that Fe 2+ potentiated the toxicity of ascaridole on oxidative phosphorylation of rat liver mitochondria. The increase of the α-tocopherol quinone/α-tocopherol ratio under these conditions indicated the initiation of lipid peroxidation by Fe 2+ -mediated ascaridole cleavage. Further ESR spin-trapping experiments demonstrated that in addition to Fe 2+ , reduced hemin, but not mitochondrial cytochrome c can activate ascaridole, explaining why ascaridole in peritoneal macrophages from BALB/c mice exhibited a higher toxicity than in isolated mitochondria.

  19. Electron microscopic radioautographic studies on macromolecular synthesis in mitochondria of animal cells in aging

    International Nuclear Information System (INIS)

    Nagata, Tetsuji

    2010-01-01

    Study aging changes of intramitochondrial DNA, RNA, protein synthesis of mouse organs during the development and aging, 30 groups of developing and aging mice (3 individuals each), from fetal day 19 to postnatal newborn at day 1, 3, 9, 14 and adult at month 1, 2, 6, 12 to 24, were injected with either 3 H-thymidine, 3 H-uriidine, or 3 H-leucine, sacrificed 1 h later and liver, adrenal, lung and testis tissues observed by electron microscopic radioautography. Accordingly, numbers of mitochondria per cell profile area, numbers of labeled mitochondria and the mitochondrial labeling index labeled with 3 H-labeled precursors showing DNA, RNA, protein synthesis in these cells (hepatocytes, 3 zones of the adrenal cortices - zona glomerulosa, fasciculata and reticularis -, adrenal medullary cells, pulmonary cells and testis cells) were counted per cells and compared among the respective developing and aging groups. The numbers of mitochondria in these cells increased from fetal day 19 to postnatal month 1 and 2. However, the numbers of labeled mitochondria and the labeling indices of intramitochondrial DNA, RNA, protein syntheses incorporating the 3 H-labeled precursors in the described tissue cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. These data support that the activity of intramitochnodrial DNA, RNA, protein syntheses in cells of these tissues increased and decreased by development and aging in mice. The intramitochondrial DNA, RNA and protein syntheses in some other organs were also reviewed and discussed. (author)

  20. Toxicity of Atorvastatin on Pancreas Mitochondria: A Justification for Increased Risk of Diabetes Mellitus.

    Science.gov (United States)

    Sadighara, Melina; Amirsheardost, Zahra; Minaiyan, Mohsen; Hajhashemi, Valiollah; Naserzadeh, Parvaneh; Salimi, Ahmad; Seydi, Enayatollah; Pourahmad, Jalal

    2017-02-01

    Statins (including atorvastatin) are a widely used class of drugs, and like all medications, they have a potential for adverse effects. Recently, it has been shown that statins also exert side effects on the pancreas. In vitro studies have suggested that this class of drugs induced a reduction in insulin secretion. Also, the use of statins is associated with a raised risk of diabetes mellitus (DM), but the mechanisms underlying statin-induced diabetes are poorly known. Literature data indicate that several statins are able to induce apoptosis signalling. This study was designed to examine the mechanism of atorvastatin on mitochondria obtained from rat pancreas. In our study, mitochondria were obtained from the pancreas and then exposed to atorvastatin and vehicle to investigate probable toxic effects. The results showed that atorvastatin (25, 50, 75, 100 and 125 μM) increased reactive oxygen species (ROS) production, mitochondrial swelling, collapse of mitochondrial membrane potential and cytochrome c release, the orchestrating factor for mitochondria-mediated apoptosis signalling. Atorvastatin also reduced the ATP levels. These results propose that the toxicity of atorvastatin on pancreas mitochondria is a key point for drug-induced apoptotic cell loss in the pancreas and therefore a justification for increased risk of DM. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  1. Preventive effect of dietary quercetin on disuse muscle atrophy by targeting mitochondria in denervated mice.

    Science.gov (United States)

    Mukai, Rie; Matsui, Naoko; Fujikura, Yutaka; Matsumoto, Norifumi; Hou, De-Xing; Kanzaki, Noriyuki; Shibata, Hiroshi; Horikawa, Manabu; Iwasa, Keiko; Hirasaka, Katsuya; Nikawa, Takeshi; Terao, Junji

    2016-05-01

    Quercetin is a major dietary flavonoid in fruits and vegetables. We aimed to clarify the preventive effect of dietary quercetin on disuse muscle atrophy and the underlying mechanisms. We established a mouse denervation model by cutting the sciatic nerve in the right leg (SNX surgery) to lack of mobilization in hind-limb. Preintake of a quercetin-mixed diet for 14days before SNX surgery prevented loss of muscle mass and atrophy of muscle fibers in the gastrocnemius muscle (GM). Phosphorylation of Akt, a key phosphorylation pathway of suppression of protein degradation, was activated in the quercetin-mixed diet group with and without SNX surgery. Intake of a quercetin-mixed diet suppressed the generation of hydrogen peroxide originating from mitochondria and elevated mitochondrial peroxisome proliferator-activated receptor-γ coactivator 1α mRNA expression as well as NADH dehydrogenase 4 expression in the GM with SNX surgery. Quercetin and its conjugated metabolites reduced hydrogen peroxide production in the mitochondrial fraction obtained from atrophied muscle. In C2C12 myotubes, quercetin reached the mitochondrial fraction. These findings suggest that dietary quercetin can prevent disuse muscle atrophy by targeting mitochondria in skeletal muscle tissue through protecting mitochondria from decreased biogenesis and reducing mitochondrial hydrogen peroxide release, which can be related to decreased hydrogen peroxide production and/or improvements on antioxidant capacity of mitochondria. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Subcellular Distribution of NAD+ between Cytosol and Mitochondria Determines the Metabolic Profile of Human Cells*

    Science.gov (United States)

    VanLinden, Magali R.; Dölle, Christian; Pettersen, Ina K. N.; Kulikova, Veronika A.; Niere, Marc; Agrimi, Gennaro; Dyrstad, Sissel E.; Palmieri, Ferdinando; Nikiforov, Andrey A.; Tronstad, Karl Johan; Ziegler, Mathias

    2015-01-01

    The mitochondrial NAD pool is particularly important for the maintenance of vital cellular functions. Although at least in some fungi and plants, mitochondrial NAD is imported from the cytosol by carrier proteins, in mammals, the mechanism of how this organellar pool is generated has remained obscure. A transporter mediating NAD import into mammalian mitochondria has not been identified. In contrast, human recombinant NMNAT3 localizes to the mitochondrial matrix and is able to catalyze NAD+ biosynthesis in vitro. However, whether the endogenous NMNAT3 protein is functionally effective at generating NAD+ in mitochondria of intact human cells still remains to be demonstrated. To modulate mitochondrial NAD+ content, we have expressed plant and yeast mitochondrial NAD+ carriers in human cells and observed a profound increase in mitochondrial NAD+. None of the closest human homologs of these carriers had any detectable effect on mitochondrial NAD+ content. Surprisingly, constitutive redistribution of NAD+ from the cytosol to the mitochondria by stable expression of the Arabidopsis thaliana mitochondrial NAD+ transporter NDT2 in HEK293 cells resulted in dramatic growth retardation and a metabolic shift from oxidative phosphorylation to glycolysis, despite the elevated mitochondrial NAD+ levels. These results suggest that a mitochondrial NAD+ transporter, similar to the known one from A. thaliana, is likely absent and could even be harmful in human cells. We provide further support for the alternative possibility, namely intramitochondrial NAD+ synthesis, by demonstrating the presence of endogenous NMNAT3 in the mitochondria of human cells. PMID:26432643

  3. Subcellular Distribution of NAD+ between Cytosol and Mitochondria Determines the Metabolic Profile of Human Cells.

    Science.gov (United States)

    VanLinden, Magali R; Dölle, Christian; Pettersen, Ina K N; Kulikova, Veronika A; Niere, Marc; Agrimi, Gennaro; Dyrstad, Sissel E; Palmieri, Ferdinando; Nikiforov, Andrey A; Tronstad, Karl Johan; Ziegler, Mathias

    2015-11-13

    The mitochondrial NAD pool is particularly important for the maintenance of vital cellular functions. Although at least in some fungi and plants, mitochondrial NAD is imported from the cytosol by carrier proteins, in mammals, the mechanism of how this organellar pool is generated has remained obscure. A transporter mediating NAD import into mammalian mitochondria has not been identified. In contrast, human recombinant NMNAT3 localizes to the mitochondrial matrix and is able to catalyze NAD(+) biosynthesis in vitro. However, whether the endogenous NMNAT3 protein is functionally effective at generating NAD(+) in mitochondria of intact human cells still remains to be demonstrated. To modulate mitochondrial NAD(+) content, we have expressed plant and yeast mitochondrial NAD(+) carriers in human cells and observed a profound increase in mitochondrial NAD(+). None of the closest human homologs of these carriers had any detectable effect on mitochondrial NAD(+) content. Surprisingly, constitutive redistribution of NAD(+) from the cytosol to the mitochondria by stable expression of the Arabidopsis thaliana mitochondrial NAD(+) transporter NDT2 in HEK293 cells resulted in dramatic growth retardation and a metabolic shift from oxidative phosphorylation to glycolysis, despite the elevated mitochondrial NAD(+) levels. These results suggest that a mitochondrial NAD(+) transporter, similar to the known one from A. thaliana, is likely absent and could even be harmful in human cells. We provide further support for the alternative possibility, namely intramitochondrial NAD(+) synthesis, by demonstrating the presence of endogenous NMNAT3 in the mitochondria of human cells. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Changes in NAD content of liver mitochondria from γ-irradiated chick embryos and chickens

    International Nuclear Information System (INIS)

    Dryanovskij, P.G.; Todorov, B.N.

    1977-01-01

    NAD content of liver mitochondria from chick embryos and chickens has been shown to decrease after irradiation with a dose of 1000 rad. The changes are better pronounced in the content of NAD than in that of NADH. The dynamics of changes in NAD and NADH contents are dependent on the embryo's age

  5. Saccharomyces cerevisiae mitochondria are required for optimal attractiveness to Drosophila melanogaster

    Science.gov (United States)

    Schiabor, Kelly M.; Quan, Allison S.; Eisen, Michael B.

    2014-01-01

    While screening a large collection of wild and laboratory yeast strains for their ability to attract Drosophila melanogaster adults, we noticed a large difference in fly preference for two nearly isogenic strains of Saccharomyces cerevisiae, BY4741 and BY4742. Using standard genetic analyses, we tracked the preference difference to the lack of mitochondria in the BY4742 strain used in the initial experiment. We used gas chromatography coupled with mass spectroscopy to examine the volatile compounds produced by BY4741 and the mitochondria-deficient BY4742, and found that they differed significantly. We observed that several ethyl esters are present at much higher levels in strains with mitochondria, even in fermentative conditions. We found that nitrogen levels in the substrate affect the production of these compounds, and that they are produced at the highest level by strains with mitochondria when fermenting natural fruit substrates. Collectively these observations demonstrate that core metabolic processes mediate the interaction between yeasts and insect vectors, and highlight the importance mitochondrial functions in yeast ecology. PMID:25462617

  6. Sensing the Stress: A Role for the UPRmt and UPRam in the Quality Control of Mitochondria

    Directory of Open Access Journals (Sweden)

    Sylvie Callegari

    2018-03-01

    Full Text Available Mitochondria exist as compartmentalized units, surrounded by a selectively permeable double membrane. Within is contained the mitochondrial genome and protein synthesis machinery, required for the synthesis of OXPHOS components and ultimately, ATP production. Despite their physical barrier, mitochondria are tightly integrated into the cellular environment. A constant flow of information must be maintained to and from the mitochondria and the nucleus, to ensure mitochondria are amenable to cell metabolic requirements and also to feedback on their functional state. This review highlights the pathways by which mitochondrial stress is signaled to the nucleus, with a particular focus on the mitochondrial unfolded protein response (UPRmt and the unfolded protein response activated by the mistargeting of proteins (UPRam. Although these pathways were originally discovered to alleviate proteotoxic stress from the accumulation of mitochondrial-targeted proteins that are misfolded or unimported, we review recent findings indicating that the UPRmt can also sense defects in mitochondrial translation. We further discuss the regulation of OXPHOS assembly and speculate on a possible role for mitochondrial stress pathways in sensing OXPHOS biogenesis.

  7. Electron microscopic radioautographic studies on macromolecular synthesis in mitochondria of animal cells in aging

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Tetsuji, E-mail: nagata@kowagakuen.ac.j [Shinshu Univ. School of Medicine, Matsumoto (Japan). Dept. of Anatomy and Cell Biology

    2010-07-01

    Study aging changes of intramitochondrial DNA, RNA, protein synthesis of mouse organs during the development and aging, 30 groups of developing and aging mice (3 individuals each), from fetal day 19 to postnatal newborn at day 1, 3, 9, 14 and adult at month 1, 2, 6, 12 to 24, were injected with either {sup 3}H-thymidine, {sup 3}H-uriidine, or {sup 3}H-leucine, sacrificed 1 h later and liver, adrenal, lung and testis tissues observed by electron microscopic radioautography. Accordingly, numbers of mitochondria per cell profile area, numbers of labeled mitochondria and the mitochondrial labeling index labeled with {sup 3}H-labeled precursors showing DNA, RNA, protein synthesis in these cells (hepatocytes, 3 zones of the adrenal cortices - zona glomerulosa, fasciculata and reticularis -, adrenal medullary cells, pulmonary cells and testis cells) were counted per cells and compared among the respective developing and aging groups. The numbers of mitochondria in these cells increased from fetal day 19 to postnatal month 1 and 2. However, the numbers of labeled mitochondria and the labeling indices of intramitochondrial DNA, RNA, protein syntheses incorporating the {sup 3}H-labeled precursors in the described tissue cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. These data support that the activity of intramitochnodrial DNA, RNA, protein syntheses in cells of these tissues increased and decreased by development and aging in mice. The intramitochondrial DNA, RNA and protein syntheses in some other organs were also reviewed and discussed. (author)

  8. Detection of PIWI and piRNAs in the mitochondria of mammalian cancer cells

    International Nuclear Information System (INIS)

    Kwon, ChangHyuk; Tak, Hyosun; Rho, Mina; Chang, Hae Ryung; Kim, Yon Hui; Kim, Kyung Tae; Balch, Curt; Lee, Eun Kyung; Nam, Seungyoon

    2014-01-01

    Highlights: • piRNA sequences were mapped to human mitochondrial (mt) genome. • We inspected small RNA-Seq datasets from somatic cell mt subcellular fractions. • Piwi and piRNA transcripts are present in mammalian somatic cancer cell mt fractions. - Abstract: Piwi-interacting RNAs (piRNAs) are 26–31 nt small noncoding RNAs that are processed from their longer precursor transcripts by Piwi proteins. Localization of Piwi and piRNA has been reported mostly in nucleus and cytoplasm of higher eukaryotes germ-line cells, where it is believed that known piRNA sequences are located in repeat regions of nuclear genome in germ-line cells. However, localization of PIWI and piRNA in mammalian somatic cell mitochondria yet remains largely unknown. We identified 29 piRNA sequence alignments from various regions of the human mitochondrial genome. Twelve out 29 piRNA sequences matched stem-loop fragment sequences of seven distinct tRNAs. We observed their actual expression in mitochondria subcellular fractions by inspecting mitochondrial-specific small RNA-Seq datasets. Of interest, the majority of the 29 piRNAs overlapped with multiple longer transcripts (expressed sequence tags) that are unique to the human mitochondrial genome. The presence of mature piRNAs in mitochondria was detected by qRT-PCR of mitochondrial subcellular RNAs. Further validation showed detection of Piwi by colocalization using anti-Piwil1 and mitochondria organelle-specific protein antibodies

  9. Transient Features in Nanosecond Pulsed Electric Fields Differentially Modulate Mitochondria and Viability

    Science.gov (United States)

    Beebe, Stephen J.; Chen, Yeong-Jer; Sain, Nova M.; Schoenbach, Karl H.; Xiao, Shu

    2012-01-01

    It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs), determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0–80 kV/cm) and short (15 ns) or long (150 ns) rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE) to determine mitochondria membrane potentials (ΔΨm). Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death. PMID:23284682

  10. Triage of oxidation-prone proteins by Sqstm1/p62 within the mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minjung [Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine and Samsung Biomedical Research Institute, Suwon-Si, Kyonggi-Do (Korea, Republic of); Shin, Jaekyoon, E-mail: jkshin@med.skku.ac.kr [Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine and Samsung Biomedical Research Institute, Suwon-Si, Kyonggi-Do (Korea, Republic of)

    2011-09-16

    Highlights: {yields} The mitochondrion contains its own protein quality control system. {yields} p62 localizes within the mitochondria and forms mega-dalton sized complexes. {yields} p62 interacts with oxidation-prone proteins and the proteins of quality control. {yields} In vitro delivery of p62 improves mitochondrial functions. {yields} p62 is implicated as a participant in mitochondrial protein quality control. -- Abstract: As the mitochondrion is vulnerable to oxidative stress, cells have evolved several strategies to maintain mitochondrial integrity, including mitochondrial protein quality control mechanisms and autophagic removal of damaged mitochondria. Involvement of an autophagy adaptor, Sqstm1/p62, in the latter process has been recently described. In the present study, we provide evidence that a portion of p62 directly localizes within the mitochondria and supports stable electron transport by forming heterogeneous protein complexes. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) of mitochondrial proteins co-purified with p62 revealed that p62 interacts with several oxidation-prone proteins, including a few components of the electron transport chain complexes, as well as multiple chaperone molecules and redox regulatory enzymes. Accordingly, p62-deficient mitochondria exhibited compromised electron transport, and the compromised function was partially restored by in vitro delivery of p62. These results suggest that p62 plays an additional role in maintaining mitochondrial integrity at the vicinity of target machineries through its function in relation to protein quality control.

  11. Oxaliplatin-induced Oxidative Stress Provokes Toxicity in Isolated Rat Liver Mitochondria.

    Science.gov (United States)

    Tabassum, Heena; Waseem, Mohammad; Parvez, Suhel; Qureshi, M Irfan

    2015-11-01

    Oxaliplatin is a widely employed platinum-derived chemotherapeutic agent commonly used for the treatment of colorectal cancer. Unfortunately, the benefit of this important drug is compromised by severe side effects such as neuropathy, ototoxicity, gastrointestinal toxicity, and hematological toxicity. Recently, few studies have also suggested the occurrence of hepatotoxicity in oxaliplatin-treated patients. Mitochondria have emerged as targets for anticancer drugs in various kinds of toxicity including hepatotoxicity that can lead to neoplastic disease. Oxidative stress is a well-established biomarker of mitochondrial toxicity. The purpose of this study was to investigate the dose-dependent damage caused by oxaliplatin on isolated liver mitochondria under in vitro conditions. The study was conducted in mitochondria isolated from liver of Wistar rats. Oxaliplatin was incubated with mitochondria in a dose-dependent manner under in vitro conditions. Oxidative stress indexes, non-enzymatic and enzymatic antioxidants were evaluated, looking at the overall armamentarium against the toxicity induced by oxaliplatin. Oxaliplatin caused a significant rise in the mitochondrial oxidative stress indexes lipid peroxidation and protein carbonyl. Alterations in the levels of non-enzymatic antioxidants and activities of enzymatic antioxidants were also observed. Oxidative stress plays an important role in the mitochondrial toxicity of oxaliplatin. The integrity of the hepatic tissue is compromised by the reactive oxygen species-mediated lipid peroxidation and protein carbonyl formation. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

  12. Study of oxidative and phosphorylative activity in mitochondria from cereal seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Plhak, F

    1973-01-01

    In the present paper the oxidative and phosphorylative activity of mitochondria isolated from rye, wheat, barley and corn seedlings are compared. Mitochondria from the shoots as well as from the roots of rye, wheat and corn oxidized succinate and in the presence of ATP or ADP exhibited the respiratory control which reached the values mostly of about 2. In the presence of ATP or ADP the decrease of inorganic phosphorus was contemporarily remarkable. The P/O ratio reached the values mostly of about 0.8 up to 1.0. The presence of ATP effected in some cases more favorable the respiratory control as well as the P/O ratio in comparison with ADP. With regard to the fact that a trapping hexokinase system was not added, the presence of endogenous hexokinase in mitochondria of experimental plants is presumed. The barley mitochondria exhibited the respiratory control as well, but instead of the decrease in inorganic phosphorus content in reaction mixture, an increase took place. It was caused by the presence of active ATP-ase which was not effectively inhibited by present NaF.

  13. Mitochondria-Targeted Antioxidant Prevents Cardiac Dysfunction Induced by Tafazzin Gene Knockdown in Cardiac Myocytes

    Directory of Open Access Journals (Sweden)

    Quan He

    2014-01-01

    Full Text Available Tafazzin, a mitochondrial acyltransferase, plays an important role in cardiolipin side chain remodeling. Previous studies have shown that dysfunction of tafazzin reduces cardiolipin content, impairs mitochondrial function, and causes dilated cardiomyopathy in Barth syndrome. Reactive oxygen species (ROS have been implicated in the development of cardiomyopathy and are also the obligated byproducts of mitochondria. We hypothesized that tafazzin knockdown increases ROS production from mitochondria, and a mitochondria-targeted antioxidant prevents tafazzin knockdown induced mitochondrial and cardiac dysfunction. We employed cardiac myocytes transduced with an adenovirus containing tafazzin shRNA as a model to investigate the effects of the mitochondrial antioxidant, mito-Tempo. Knocking down tafazzin decreased steady state levels of cardiolipin and increased mitochondrial ROS. Treatment of cardiac myocytes with mito-Tempo normalized tafazzin knockdown enhanced mitochondrial ROS production and cellular ATP decline. Mito-Tempo also significantly abrogated tafazzin knockdown induced cardiac hypertrophy, contractile dysfunction, and cell death. We conclude that mitochondria-targeted antioxidant prevents cardiac dysfunction induced by tafazzin gene knockdown in cardiac myocytes and suggest mito-Tempo as a potential therapeutic for Barth syndrome and other dilated cardiomyopathies resulting from mitochondrial oxidative stress.

  14. Phospholipase activity in rat liver mitochondria studied by the use of endogenous substrates.

    Science.gov (United States)

    Bjornstad, P

    1966-09-01

    The hydrolysis of endogenous phosphatidyl ethanolamine and lecithin in rat liver mitochondria has been studied by using mitochondria from rats injected with ethanolamine-1,2-(14)C or choline-1,2-(14)C. A phospholipase A-like enzyme has been demonstrated, which catalyzes the hydrolysis of one fatty acid ester linkage in phosphatidyl ethanolamine and lecithin. Phosphatidyl ethanolamine is hydrolyzed in preference to lecithin and the main reaction products are free fatty acids and lysophosphatidyl ethanolamine. The further breakdown of lysophospholipids appears to be limited in mitochondria, which indicates that lysophospholipase activity is mainly located extramitochondrially. The enzymic system is greatly stimulated by calcium ions, and also slightly by magnesium ions, while EDTA inhibits it almost completely. These findings are discussed in relation to previous observations on the effect of calcium and of EDTA on the functions of mitochondria. The possible function of the mitochondrial phospholipase for the formation of phospholipids with special fatty acids at the alpha- and -position is discussed.

  15. Polyhydroxybutyrate Targets Mammalian Mitochondria and Increases Permeability of Plasmalemmal and Mitochondrial Membranes

    Science.gov (United States)

    Elustondo, Pia A.; Angelova, Plamena R.; Kawalec, Michał; Michalak, Michał; Kurcok, Piotr; Abramov, Andrey Y.; Pavlov, Evgeny V.

    2013-01-01

    Poly(3-hydroxybutyrate) (PHB) is a polyester of 3-hydroxybutyric acid (HB) that is ubiquitously present in all organisms. In higher eukaryotes PHB is found in the length of 10 to 100 HB units and can be present in free form as well as in association with proteins and inorganic polyphosphate. It has been proposed that PHB can mediate ion transport across lipid bilayer membranes. We investigated the ability of PHB to interact with living cells and isolated mitochondria and the effects of these interactions on membrane ion transport. We performed experiments using a fluorescein derivative of PHB (fluo-PHB). We found that fluo-PHB preferentially accumulated inside the mitochondria of HeLa cells. Accumulation of fluo-PHB induced mitochondrial membrane depolarization. This membrane depolarization was significantly delayed by the inhibitor of the mitochondrial permeability transition pore - Cyclosporin A. Further experiments using intact cells as well as isolated mitochondria confirmed that the effects of PHB directly linked to its ability to facilitate ion transport, including calcium, across the membranes. We conclude that PHB demonstrates ionophoretic properties in biological membranes and this effect is most profound in mitochondria due to the selective accumulation of the polymer in this organelle. PMID:24086638

  16. Detection of PIWI and piRNAs in the mitochondria of mammalian cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, ChangHyuk, E-mail: netbuyer@hanmail.net [Cancer Genomics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Tak, Hyosun, E-mail: chuberry@naver.com [Department of Biochemistry, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Rho, Mina, E-mail: minarho@hanyang.ac.kr [Department of Computer Science, Hanyang University, Seoul 133-791 (Korea, Republic of); Chang, Hae Ryung, E-mail: heyhae@ncc.re.kr [New Experimental Therapeutics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Kim, Yon Hui, E-mail: yhkim@ncc.re.kr [New Experimental Therapeutics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Kim, Kyung Tae, E-mail: bioktkim@ncc.re.kr [Molecular Epidemiology Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Balch, Curt, E-mail: curt.balch@gmail.com [Medical Sciences Program, Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Bloomington, IN 47405 (United States); Lee, Eun Kyung, E-mail: leeek@catholic.ac.kr [Department of Biochemistry, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Nam, Seungyoon, E-mail: seungyoon.nam@ncc.re.kr [Cancer Genomics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of)

    2014-03-28

    Highlights: • piRNA sequences were mapped to human mitochondrial (mt) genome. • We inspected small RNA-Seq datasets from somatic cell mt subcellular fractions. • Piwi and piRNA transcripts are present in mammalian somatic cancer cell mt fractions. - Abstract: Piwi-interacting RNAs (piRNAs) are 26–31 nt small noncoding RNAs that are processed from their longer precursor transcripts by Piwi proteins. Localization of Piwi and piRNA has been reported mostly in nucleus and cytoplasm of higher eukaryotes germ-line cells, where it is believed that known piRNA sequences are located in repeat regions of nuclear genome in germ-line cells. However, localization of PIWI and piRNA in mammalian somatic cell mitochondria yet remains largely unknown. We identified 29 piRNA sequence alignments from various regions of the human mitochondrial genome. Twelve out 29 piRNA sequences matched stem-loop fragment sequences of seven distinct tRNAs. We observed their actual expression in mitochondria subcellular fractions by inspecting mitochondrial-specific small RNA-Seq datasets. Of interest, the majority of the 29 piRNAs overlapped with multiple longer transcripts (expressed sequence tags) that are unique to the human mitochondrial genome. The presence of mature piRNAs in mitochondria was detected by qRT-PCR of mitochondrial subcellular RNAs. Further validation showed detection of Piwi by colocalization using anti-Piwil1 and mitochondria organelle-specific protein antibodies.

  17. The Activity of Menkes Disease Protein ATP7A Is Essential for Redox Balance in Mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Ashima; Yang, Haojun; Duffy, Megan; Robinson, Emily; Conrad-Antoville, Arianrhod; Lu, Ya-Wen; Capps, Tony; Braiterman, Lelita; Wolfgang, Michael; Murphy, Michael P.; Yi, Ling; Kaler, Stephen G.; Lutsenko, Svetlana; Ralle, Martina

    2016-05-16

    Copper-transporting ATPase ATP7A is essential for mammalian copper homeostasis. Loss of ATP7A activity is associated with fatal Menkes disease and various other pathologies. In cells, ATP7A inactivation disrupts copper transport from the cytosol into the secretory pathway. Using fibroblasts from Menkes disease patients and mouse 3T3-L1 cells with a CRISPR/Cas9-inactivated ATP7A, we demonstrate that ATP7A dysfunction is also damaging to mitochondrial redox balance. In these cells, copper accumulates in nuclei, cytosol, and mitochondria, causing distinct changes in their redox environment. Quantitative imaging of live cells using GRX1-roGFP2 and HyPer sensors reveals highest glutathione oxidation and elevation of H2O2 in mitochondria, whereas the redox environment of nuclei and the cytosol is much less affected. Decreasing the H2O2 levels in mitochondria with MitoQ does not prevent glutathione oxidation; i.e. elevated copper and not H2O2 is a primary cause of glutathione oxidation. Redox misbalance does not significantly affect mitochondrion morphology or the activity of respiratory complex IV but markedly increases cell sensitivity to even mild glutathione depletion, resulting in loss of cell viability. Thus, ATP7A activity protects mitochondria from excessive copper entry, which is deleterious to redox buffers. Mitochondrial redox misbalance could significantly contribute to pathologies associated with ATP7A inactivation in tissues with paradoxical accumulation of copper (i.e. renal epithelia).

  18. Ketogenesis in rat-liver mitochondria: Stimulation by palmityl-coenzyme A

    NARCIS (Netherlands)

    Vaartjes, W.J.; Lopes-Cardozo, M.; Bergh, S.G. van den

    1972-01-01

    It is well-known that the movement of adenine nucleotides (AdN) across the inner mitochondrial membrane is markedly decreased both by unsaturated and by saturated long-chain fatty acids. A similar effect is displayed by palmityl-CoA as demonstrated recently with isolated mitochondria of rat

  19. Fungi of genus Alternaria occurring on tomato

    Directory of Open Access Journals (Sweden)

    Joanna Marcinkowska

    2013-12-01

    Full Text Available Tomato early blight in central Poland was caused by Alternaria solani (A. porri f. sp., solani and A. alernata (A. tenuis. A. alternata was isolated more often than A. solani. All isolates of A. solani in controlled conditions killed tomato seedlings, while pathogenic isolates of A. alternata caused only slight seedling blight. In greenhouse tests A. solani proved to be strongly pathogenic for leaves and stems of tomato but A. alternata was weakly pathogenic. The latter species attacked only injured fruits while, A. solanicould penetrate through undamaged peel of fruits. Both of these species caused the same type of symptoms; the differences consisted only in intensification of disease symptoms. During 1974 and 1975 field tomatoes were moderately attacked by early blight. Thebest development of this disease occurred by the turn of August and September. Determinate variety 'New Yorker' was distinguished by more severe infection of stem parts of tomato whereas the fruits of a stock variety 'Apollo' were more strongly attacked.

  20. Uranium occurence in California near Bucaramanga (Columbia)

    International Nuclear Information System (INIS)

    Heider Polania, J.

    1980-01-01

    The mining district of California, Bucaramanga, is on the west side of the Cordillera Oriental in the Santander massif region. The oldest rocks of the area form a complex of metamorphites and migmatites of the predevonic age. Amphibolite various types of paragneiss and orthogneiss are represented. Several stages of metamorphism can be documented in some rocks, as well as double anatexis. Triassic to jurassic quarz diorites and leukogranites show wide distribution. Porphyric rocks of granodioritic to granitic composition, to which the uranium mineralization is mainly bonded, intruded into the sediments of the lower cretaceous. Atomic absorption spectral analyses were carried out for the elements Cu, Zn and Li, as well as the uranium contents of some samples using fluorimetry. Uranium is primarily bonded to pitch blende and coffinite. The latter mostly occur in fine distribution grown in quarz and belong to the most recent mineralization phase. Autunite, meta-autunite, torbernite, meta-torbernite, zeunerite, meta-zeunerite and meta uranocircite detected as secondary uranium minerals. (orig./HP) [de

  1. Bioassay of naturally occurring allelochemicals for phytotoxicity.

    Science.gov (United States)

    Leather, G R; Einhellig, F A

    1988-10-01

    The bioassay has been one of the most widely used tests to demonstrate allelopathic activity. Often, claims that a particular plant species inhibits the growth of another are based entirely on the seed germination response to solvent extracts of the suspected allelopathic plant; few of these tests are of value in demonstrating allelopathy under natural conditions. The veracity of the bioassay for evaluating naturally occurring compounds for phytotoxicity depends upon the physiological and biochemical response capacity of the bioassay organism and the mechanism(s) of action of the allelochemicals. The possibility that more than one allelochemical, acting in concert at very low concentrations, may be responsible for an observed allelopathic effect makes it imperative that bioassays be extremely sensitive to chemical growth perturbation agents. Among the many measures of phytotoxicity of allelochemicals, the inhibition (or stimulation) of seed germination, radicle elongation, and/or seedling growth have been the parameters of choice for most investigations. Few of these assays have been selected with the view towards the possible mechanism of the allelopathic effect.

  2. Cannabinoid CB1 Receptors Are Localized in Striated Muscle Mitochondria and Regulate Mitochondrial Respiration

    Directory of Open Access Journals (Sweden)

    Juan Mendizabal-Zubiaga

    2016-10-01

    Full Text Available The cannabinoid type 1 (CB1 receptor is widely distributed in the brain and peripheral organs where it regulates cellular functions and metabolism. In the brain, CB1 is mainly localized on presynaptic axon terminals but is also found on mitochondria (mtCB1, where it regulates cellular respiration and energy production. Likewise, CB1 is localized on muscle mitochondria, but very little is known about it. The aim of this study was to further investigate in detail the distribution and functional role of mtCB1 in three different striated muscles. Immunoelectron microscopy for CB1 was used in skeletal muscles (gastrocnemius and rectus abdominis and myocardium from wild-type and CB1-KO mice. Functional assessments were performed in mitochondria purified from the heart of the mice and the mitochondrial oxygen consumption upon application of different acute delta-9-tetrahidrocannabinol (Δ9-THC concentrations (100 nM or 200 nM was monitored. About 26% of the mitochondrial profiles in gastrocnemius, 22% in the rectus abdominis and 17% in the myocardium expressed CB1. Furthermore, the proportion of mtCB1 versus total CB1 immunoparticles was about 60% in the gastrocnemius, 55% in the rectus abdominis and 78% in the myocardium. Importantly, the CB1 immunolabeling pattern disappeared in muscles of CB1-KO mice. Functionally, acute 100 nM or 200 nM THC treatment specifically decreased mitochondria coupled respiration between 12% and 15% in wild-type isolated mitochondria of myocardial muscles but no significant difference was noticed between THC treated and vehicle in mitochondria isolated from CB1-KO heart. Furthermore, gene expression of key enzymes involved in pyruvate synthesis, tricarboxylic acid (TCA cycle and mitochondrial respiratory chain was evaluated in the striated muscle of CB1-WT and CB1-KO. CB1-KO showed an increase in the gene expression of Eno3, Pkm2, and Pdha1, suggesting an increased production of pyruvate. In contrast, no significant

  3. The importance of board independence

    NARCIS (Netherlands)

    Zijl, N.J.M.

    2012-01-01

    Although the attributed importance of board independence is high, a clear definition of independence does not exist. Furthermore, the aim and consequences of independence are the subject of discussion and empirical evidence about the impact of independence is weak and disputable. Despite this lack

  4. Naturally occurring flavonoids against human norovirus surrogates.

    Science.gov (United States)

    Su, Xiaowei; D'Souza, Doris H

    2013-06-01

    Naturally occurring plant-derived flavonoids are reported to have antibacterial, antiviral, and pharmacological activities. The objectives of this study were to determine the antiviral effects of four flavonoids (myricetin, L-epicatechin, tangeretin, and naringenin) on the infectivity of food borne norovirus surrogates after 2 h at 37 °C. The lab-culturable surrogates, feline calicivirus (FCV-F9) at titers of ~7 log₁₀ PFU/ml (high titer) or ~5 log₁₀ PFU/ml (low titer) and murine norovirus (MNV-1) at ~5 log₁₀ PFU/ml, were mixed with equal volumes of myricetin, L-epicatechin, tangeretin, or naringenin at concentrations of 0.5 or 1 mM, and incubated for 2 h at 37 °C. Treatments of viruses were neutralized in cell culture medium containing 10 % heat-inactivated fetal bovine serum, serially diluted, and plaque assayed. Each treatment was replicated thrice and assayed in duplicate. FCV-F9 (low titer) was not found to be reduced by tangeretin or naringenin, but was reduced to undetectable levels by myricetin at both concentrations. Low titer FCV-F9 was also decreased by 1.40 log₁₀ PFU/ml with L-epicatechin at 0.5 mM. FCV-F9 at high titers was decreased by 3.17 and 0.72 log₁₀ PFU/ml with myricetin and L-epicatechin at 0.5 mM, and 1.73 log10 PFU/ml with myricetin at 0.25 mM, respectively. However, MNV-1 showed no significant inactivation by the four tested treatments. The antiviral effects of the tested flavonoids are dependent on the virus type, titer, and dose. Further research will focus on understanding the antiviral mechanism of myricetin and L-epicatechin.

  5. Differential dormancy of co-occurring copepods

    Science.gov (United States)

    Ohman, Mark D.; Drits, Aleksandr V.; Elizabeth Clarke, M.; Plourde, Stéphane

    1998-08-01

    Four species of planktonic calanoid copepods that co-occur in the California Current System ( Eucalanus californicus Johnson, Rhincalanus nasutus Giesbrecht, Calanus pacificus californicus Brodsky, and Metridia pacifica Brodsky) were investigated for evidence of seasonal dormancy in the San Diego Trough. Indices used to differentiate actively growing from dormant animals included developmental stage structure and vertical distribution; activity of aerobic metabolic enzymes (Citrate Synthase and the Electron Transfer System complex); investment in depot lipids (wax esters and triacylglycerols); in situ grazing activity from gut fluorescence; and egg production rates in simulated in situ conditions. None of the 4 species exhibited a canonical calanoid pattern of winter dormancy - i.e., synchronous developmental arrest as copepodid stage V, descent into deep waters, reduced metabolism, and lack of winter reproduction. Instead, Calanus pacificus californicus has a biphasic life history in this region, with an actively reproducing segment of the population in surface waters overlying a deep dormant segment in winter. Eucalanus californicus is dormant as both adult females and copepodid V's, although winter females respond relatively rapidly to elevated food and temperature conditions; they begin feeding and producing eggs within 2-3 days. Rhincalanus nasutus appears to enter dormancy as adult females, although the evidence is equivocal. Metridia pacifica shows no evidence of dormancy, with sustained active feeding, diel vertical migration behavior, and elevated activity of metabolic enzymes in December as well as in June. The four species also differ markedly in water content, classes of storage lipids, and specific activity of Citrate Synthase. These results suggest that copepod dormancy traits and structural composition reflect diverse adaptations to regional environmental conditions rather than a uniform, canonical series of traits that remain invariant among taxa

  6. The energy blockers 3-bromopyruvate and lonidamine: effects on bioenergetics of brain mitochondria.

    Science.gov (United States)

    Macchioni, Lara; Davidescu, Magdalena; Roberti, Rita; Corazzi, Lanfranco

    2014-10-01

    Tumor cells favor abnormal energy production via aerobic glycolysis and show resistance to apoptosis, suggesting the involvement of mitochondrial dysfunction. The differences between normal and cancer cells in their energy metabolism provide a biochemical basis for developing new therapeutic strategies. The energy blocker 3-bromopyruvate (3BP) can eradicate liver cancer in animals without associated toxicity, and is a potent anticancer towards glioblastoma cells. Since mitochondria are 3BP targets, in this work the effects of 3BP on the bioenergetics of normal rat brain mitochondria were investigated in vitro, in comparison with the anticancer agent lonidamine (LND). Whereas LND impaired oxygen consumption dependent on any complex of the respiratory chain, 3BP was inhibitory to malate/pyruvate and succinate (Complexes I and II), but preserved respiration from glycerol-3-phosphate and ascorbate (Complex IV). Accordingly, although electron flow along the respiratory chain and ATP levels were decreased by 3BP in malate/pyruvate- and succinate-fed mitochondria, they were not significantly influenced from glycerol-3-phosphate- or ascorbate-fed mitochondria. LND produced a decrease in electron flow from all substrates tested. No ROS were produced from any substrate, with the exception of 3BP-induced H(2)O(2) release from succinate, which suggests an antimycin-like action of 3BP as an inhibitor of Complex III. We can conclude that 3BP does not abolish completely respiration and ATP synthesis in brain mitochondria, and has a limited effect on ROS production, confirming that this drug may have limited harmful effects on normal cells.

  7. Reactive oxygen species and nitric oxide in plant mitochondria: origin and redundant regulatory systems.

    Science.gov (United States)

    Blokhina, Olga; Fagerstedt, Kurt V

    2010-04-01

    Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and fruit carbohydrates may be plenty, whereas oxygen levels are falling. Several enzymatic complexes in mitochondrial electron transport chain (ETC) are capable of reactive oxygen species (ROS) formation under physiological and pathological conditions. Inherently connected parameters such as the redox state of electron carriers in the ETC, ATP synthase activity and inner mitochondrial membrane potential, when affected by external stimuli, can give rise to ROS formation via complexes I and III, and by reverse electron transport (RET) from complex II. Superoxide radicals produced are quickly scavenged by superoxide dismutase (MnSOD), and the resulting H(2)O(2) is detoxified by peroxiredoxin-thioredoxin system or by the enzymes of ascorbate-glutathione cycle, found in the mitochondrial matrix. Arginine-dependent nitric oxide (NO)-releasing activity of enzymatic origin has been detected in plant mitochondria. The molecular identity of the enzyme is not clear but the involvement of mitochondria-localized enzymes responsible for arginine catabolism, arginase and ornithine aminotransferase has been shown in the regulation of NO efflux. Besides direct control by antioxidants, mitochondrial ROS production is tightly controlled by multiple redundant systems affecting inner membrane potential: NAD(P)H-dependent dehydrogenases, alternative oxidase (AOX), uncoupling proteins, ATP-sensitive K(+) channel and a number of matrix and intermembrane enzymes capable of direct electron donation to ETC. NO removal, on the other hand, takes place either by reactions with molecular oxygen or superoxide resulting in peroxynitrite, nitrite or nitrate

  8. Early transcriptional changes in cardiac mitochondria during chronic doxorubicin exposure and mitigation by dexrazoxane in mice

    Energy Technology Data Exchange (ETDEWEB)

    Vijay, Vikrant; Moland, Carrie L.; Han, Tao; Fuscoe, James C. [Personalized Medicine Branch, Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Lee, Taewon [Department of Mathematics, Korea University, Sejong (Korea, Republic of); Herman, Eugene H. [Toxicology and Pharmacology Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, The National Cancer Institute, 9609 Medical Center Drive, Rockville, MD 20850-9734 (United States); Jenkins, G. Ronald [Personalized Medicine Branch, Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Lewis, Sherry M. [Office of Scientific Coordination, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Cummings, Connie A. [UltraPath Imaging, 2228 Page Road, Durham, NC 27703 (United States); Gao, Yuan; Cao, Zhijun; Yu, Li-Rong [Biomarkers and Alternative Models Branch, Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Desai, Varsha G., E-mail: varsha.desai@fda.hhs.gov [Personalized Medicine Branch, Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States)

    2016-03-15

    Identification of early biomarkers of cardiotoxicity could help initiate means to ameliorate the cardiotoxic actions of clinically useful drugs such as doxorubicin (DOX). Since DOX has been shown to target mitochondria, transcriptional levels of mitochondria-related genes were evaluated to identify early candidate biomarkers in hearts of male B6C3F{sub 1} mice given a weekly intravenous dose of 3 mg/kg DOX or saline (SAL) for 2, 3, 4, 6, or 8 weeks (6, 9, 12, 18, or 24 mg/kg cumulative DOX doses, respectively). Also, a group of mice was pretreated (intraperitoneally) with the cardio-protectant, dexrazoxane (DXZ; 60 mg/kg) 30 min before each weekly dose of DOX or SAL. At necropsy a week after the last dose, increased plasma concentrations of cardiac troponin T (cTnT) were detected at 18 and 24 mg/kg cumulative DOX doses, whereas myocardial alterations were observed only at the 24 mg/kg dose. Of 1019 genes interrogated, 185, 109, 140, 184, and 451 genes were differentially expressed at 6, 9, 12, 18, and 24 mg/kg cumulative DOX doses, respectively, compared to concurrent SAL-treated controls. Of these, expression of 61 genes associated with energy metabolism and apoptosis was significantly altered before and after occurrence of myocardial injury, suggesting these as early genomics markers of cardiotoxicity. Much of these DOX-induced transcriptional changes were attenuated by pretreatment of mice with DXZ. Also, DXZ treatment significantly reduced plasma cTnT concentration and completely ameliorated cardiac alterations induced by 24 mg/kg cumulative DOX. This information on early transcriptional changes during DOX treatment may be useful in designing cardioprotective strategies targeting mitochondria. - Highlights: • Altered mitochondria-related gene expression before heart injury by doxorubicin • Dexrazoxane mitigated doxorubicin-induced early expression changes in mitochondria. • Dexrazoxane completely ameliorated doxorubicin-induced pathology in mouse heart.

  9. High Throughput Microplate Respiratory Measurements Using Minimal Quantities Of Isolated Mitochondria

    Science.gov (United States)

    Rogers, George W.; Brand, Martin D.; Petrosyan, Susanna; Ashok, Deepthi; Elorza, Alvaro A.; Ferrick, David A.; Murphy, Anne N.

    2011-01-01

    Recently developed technologies have enabled multi-well measurement of O2 consumption, facilitating the rate of mitochondrial research, particularly regarding the mechanism of action of drugs and proteins that modulate metabolism. Among these technologies, the Seahorse XF24 Analyzer was designed for use with intact cells attached in a monolayer to a multi-well tissue culture plate. In order to have a high throughput assay system in which both energy demand and substrate availability can be tightly controlled, we have developed a protocol to expand the application of the XF24 Analyzer to include isolated mitochondria. Acquisition of optimal rates requires assay conditions that are unexpectedly distinct from those of conventional polarography. The optimized conditions, derived from experiments with isolated mouse liver mitochondria, allow multi-well assessment of rates of respiration and proton production by mitochondria attached to the bottom of the XF assay plate, and require extremely small quantities of material (1–10 µg of mitochondrial protein per well). Sequential measurement of basal, State 3, State 4, and uncoupler-stimulated respiration can be made in each well through additions of reagents from the injection ports. We describe optimization and validation of this technique using isolated mouse liver and rat heart mitochondria, and apply the approach to discover that inclusion of phosphatase inhibitors in the preparation of the heart mitochondria results in a specific decrease in rates of Complex I-dependent respiration. We believe this new technique will be particularly useful for drug screening and for generating previously unobtainable respiratory data on small mitochondrial samples. PMID:21799747

  10. High throughput microplate respiratory measurements using minimal quantities of isolated mitochondria.

    Directory of Open Access Journals (Sweden)

    George W Rogers

    Full Text Available Recently developed technologies have enabled multi-well measurement of O(2 consumption, facilitating the rate of mitochondrial research, particularly regarding the mechanism of action of drugs and proteins that modulate metabolism. Among these technologies, the Seahorse XF24 Analyzer was designed for use with intact cells attached in a monolayer to a multi-well tissue culture plate. In order to have a high throughput assay system in which both energy demand and substrate availability can be tightly controlled, we have developed a protocol to expand the application of the XF24 Analyzer to include isolated mitochondria. Acquisition of optimal rates requires assay conditions that are unexpectedly distinct from those of conventional polarography. The optimized conditions, derived from experiments with isolated mouse liver mitochondria, allow multi-well assessment of rates of respiration and proton production by mitochondria attached to the bottom of the XF assay plate, and require extremely small quantities of material (1-10 µg of mitochondrial protein per well. Sequential measurement of basal, State 3, State 4, and uncoupler-stimulated respiration can be made in each well through additions of reagents from the injection ports. We describe optimization and validation of this technique using isolated mouse liver and rat heart mitochondria, and apply the approach to discover that inclusion of phosphatase inhibitors in the preparation of the heart mitochondria results in a specific decrease in rates of Complex I-dependent respiration. We believe this new technique will be particularly useful for drug screening and for generating previously unobtainable respiratory data on small mitochondrial samples.

  11. Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity.

    Directory of Open Access Journals (Sweden)

    Giovanni Dalmasso

    Full Text Available Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis and the removal of damaged mitochondria by selective autophagy (mitophagy. While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1 mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2 restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3 maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4 our model suggests sources of, and stress conditions

  12. Even a Chronic Mild Hyperglycemia Affects Membrane Fluidity and Lipoperoxidation in Placental Mitochondria in Wistar Rats

    Science.gov (United States)

    Figueroa-García, María del Consuelo; Espinosa-García, María Teresa; Martinez-Montes, Federico; Palomar-Morales, Martín; Mejía-Zepeda, Ricardo

    2015-01-01

    It is known the deleterious effects of diabetes on embryos, but the effects of diabetes on placenta and its mitochondria are still not well known. In this work we generated a mild hyperglycemia model in female wistar rats by intraperitoneal injection of streptozotocin in 48 hours-old rats. The sexual maturity onset of the female rats was delayed around 6–7 weeks and at 16 weeks-old they were mated, and sacrificed at day 19th of pregnancy. In placental total tissue and isolated mitochondria, the fatty acids composition was analyzed by gas chromatography, and lipoperoxidation was measured by thiobarbituric acid reactive substances. Membrane fluidity in mitochondria was measured with the excimer forming probe dipyrenylpropane and mitochondrial function was measured with a Clark-type electrode. The results show that even a chronic mild hyperglycemia increases lipoperoxidation and decreases mitochondrial function in placenta. Simultaneously, placental fatty acids metabolism in total tissue is modified but in a different way than in placental mitochondria. Whereas the chronic mild hyperglycemia induced a decrease in unsaturated to saturated fatty acids ratio (U/S) in placental total tissue, the ratio increased in placental mitochondria. The measurements of membrane fluidity showed that fluidity of placenta mitochondrial membranes increased with hyperglycemia, showing consistency with the fatty acids composition through the U/S index. The thermotropic characteristics of mitochondrial membranes were changed, showing lower transition temperature and activation energies. All of these data together demonstrate that even a chronic mild hyperglycemia during pregnancy of early reproductive Wistar rats, generates an increment of lipoperoxidation, an increase of placental mitochondrial membrane fluidity apparently derived from changes in fatty acids composition and consequently, mitochondrial malfunction. PMID:26630275

  13. Proteome Analysis of Subsarcolemmal Cardiomyocyte Mitochondria: A Comparison of Different Analytical Platforms

    Directory of Open Access Journals (Sweden)

    Francesco Giorgianni

    2014-05-01

    Full Text Available Mitochondria are complex organelles that play critical roles in diverse aspects of cellular function. Heart disease and a number of other pathologies are associated with perturbations in the molecular machinery of the mitochondria. Therefore, comprehensive, unbiased examination of the mitochondrial proteome represents a powerful approach toward system-level insights into disease mechanisms. A crucial aspect in proteomics studies is design of bioanalytical strategies that maximize coverage of the complex repertoire of mitochondrial proteins. In this study, we evaluated the performance of gel-based and gel-free multidimensional platforms for profiling of the proteome in subsarcolemmal mitochondria harvested from rat heart. We compared three different multidimensional proteome fractionation platforms: polymeric reversed-phase liquid chromatography at high pH (PLRP, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, and isoelectric focusing (IEF separations combined with liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS, and bioinformatics for protein identification. Across all three platforms, a total of 1043 proteins were identified. Among the three bioanalytical strategies, SDS-PAGE followed by LC-MS/MS provided the best coverage of the mitochondrial proteome. With this platform, 890 proteins with diverse physicochemical characteristics were identified; the mitochondrial protein panel encompassed proteins with various functional roles including bioenergetics, protein import, and mitochondrial fusion. Taken together, results of this study provide a large-scale view of the proteome in subsarcolemmal mitochondria from the rat heart, and aid in the selection of optimal bioanalytical platforms for differential protein expression profiling of mitochondria in health and disease.

  14. Autonomy, Independence, Inclusion

    Directory of Open Access Journals (Sweden)

    Filippo Angelucci

    2015-04-01

    Full Text Available The living environment must not only meet the primary needs of living, but also the expectations of improvement of life and social relations and people’s work. The need for a living environment that responds to the needs of users with their different abilities, outside of standardizations, is increasingly felt as autonomy, independence and well-being are the result of real usability and adaptability of the spaces. The project to improve the inclusivity of living space and to promote the rehabilitation of fragile users need to be characterized as an interdisciplinary process in which the integration of specialized contributions leads to adaptive customization of space solutions and technological that evolve with the changing needs, functional capacities and abilities of individuals.

  15. Saikosaponin d induces cell death through caspase-3-dependent, caspase-3-independent and mitochondrial pathways in mammalian hepatic stellate cells

    International Nuclear Information System (INIS)

    Chen, Ming-Feng; Huang, S. Joseph; Huang, Chao-Cheng; Liu, Pei-Shan; Lin, Kun-I; Liu, Ching-Wen; Hsieh, Wen-Chuan; Shiu, Li-Yen; Chen, Chang-Han

    2016-01-01

    Saikosaponin d (SSd) is one of the main active triterpene saponins in Bupleurum falcatum. It has a steroid-like structure, and is reported to have pharmacological activities, including liver protection in rat, cell cycle arrest and apoptosis induction in several cancer cell lines. However, the biological functions and molecular mechanisms of mammalian cells under SSd treatment are still unclear. The cytotoxicity and apoptosis of hepatic stellate cells (HSCs) upon SSd treatment were discovered by MTT assay, colony formation assay and flow cytometry. The collage I/III, caspase activity and apoptotic related genes were examined by quantitative PCR, Western blotting, immunofluorescence and ELISA. The mitochondrial functions were monitored by flow cytometry, MitoTracker staining, ATP production and XF24 bioenergetic assay. This study found that SSd triggers cell death via an apoptosis path. An example of this path might be typical apoptotic morphology, increased sub-G1 phase cell population, inhibition of cell proliferation and activation of caspase-3 and caspase-9. However, the apoptotic effects induced by SSd are partially blocked by the caspase-3 inhibitor, Z-DEVD-FMK, suggesting that SSd may trigger both HSC-T6 and LX-2 cell apoptosis through caspase-3-dependent and independent pathways. We also found that SSd can trigger BAX and BAK translocation from the cytosol to the mitochondria, resulting in mitochondrial function inhibition, membrane potential disruption. Finally, SSd also increases the release of apoptotic factors. The overall analytical data indicate that SSd-elicited cell death may occur through caspase-3-dependent, caspase-3-independent and mitochondrial pathways in mammalian HSCs, and thus can delay the formation of liver fibrosis by reducing the level of HSCs

  16. Information Needs While A Disaster Is Occurring

    Science.gov (United States)

    Perry, S. C.

    2010-12-01

    that rainfall intensity at their homes might be less than the intensity up in the mountains where the debris flows would start. Nor did they know that debris flows travel too quickly to be outrun. These and many other examples indicate need for social and natural scientists to increase awareness of what to expect when the disaster strikes. This information must be solidly understood before the event occurs - while a disaster is unfolding there are no teachable moments. Case studies indicate that even those who come into a disaster well educated about the phenomenon can struggle to apply what they know when the real situation is at hand. In addition, psychological studies confirm diminished ability to comprehend information at times of stress.

  17. Mechanisms of generation of local ΔpH in mitochondria and bacteria.

    Science.gov (United States)

    Medvedev, E S; Stuchebrukhov, A A

    2014-05-01

    The concepts of global and local coupling between proton generators, the enzymes of the respiratory chain, and the consumer, the ATP synthase, coexist in the theory of oxidative phosphorylation. Global coupling is trivial proton transport via the aqueous medium, whereas local coupling implies that the protons pumped are consumed before they escape to the bulk phase. In this work, the conditions for the occurrence of local coupling are explored. It is supposed that the membrane retains protons near its surface and that the proton current generated by the proton pumps rapidly decreases with increasing proton motive force (pmf). It is shown that the competition between the processes of proton translocation across the membrane and their dissipation from the surface to the bulk can result in transient generation of a local ΔpH in reply to a sharp change in pmf; the appearance of local ΔpH, in turn, leads to rapid recovery of the pmf, and hence, it provides for stabilization of the potential at the membrane. Two mechanisms of such kind are discussed: 1) pH changes in the surface area due to proton pumping develop faster than those due to proton escape to the bulk; 2) the former does not take place, but the protons leaving the surface do not equilibrate with the bulk immediately; rather, they give rise to a non-equilibrium concentration near the surface and, as a result, to a back proton flow to the surface. The first mechanism is more efficient, but it does not occur in mitochondria and neutrophilic bacteria, whereas the second can produce ΔpH on the order of unity. In the absence of proton retardation at the surface, local ΔpH does not arise, whereas the formation of global ΔpH is possible only at buffer concentration of less than 10 mM. The role of the mechanisms proposed in transitions between States 3 and 4 of the respiratory chain is discussed. The main conclusion is that surface protons, under conditions where they play a role, support stabilization of the

  18. Regulation of pyruvate oxidation in blowfly flight muscle mitochondria: requirement for ADP.

    Science.gov (United States)

    Bulos, B A; Thomas, B J; Shukla, S P; Sacktor, B

    1984-11-01

    Blowfly (Phormia regina) flight muscle mitochondria oxidized pyruvate ( + proline) in the presence of either ADP (coupled respiration) or carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP-uncoupled respiration). There was an absolute requirement for ADP (Km = 8.0 microM) when pyruvate oxidation was stimulated by FCCP in the presence of oligomycin. This requirement for ADP was limited to the oxidation of pyruvate; uncoupled alpha-glycerolphosphate oxidation proceeded maximally even in the absence of added ADP. Atractylate inhibited uncoupled pyruvate oxidation whether added before (greater than 99%) or after (95%) initiation of respiration with FCCP. In the presence of FCCP, oligomycin, and limiting concentrations of ADP (less than 110 microM), there was a shutoff in the uptake of oxygen. This inhibition of respiration was completely reversed by the addition of more ADP. Plots of net oxygen uptake as a function of the limiting ADP concentration were linear; the observed ADP/O ratio was 0.22 +/- 0.025. An ADP/O ratio of 0.2 was predicted if phosphorylation occurred only at the succinyl-CoA synthetase step of the tricarboxylate cycle. Experiments performed in the presence of limiting concentrations of ADP, and designed to monitor changes in the mitochondrial content of ADP and ATP, demonstrated that the shutoff in oxygen uptake was not due to the presence of a high intramitochondrial concentration of ATP. Indeed, ATP, added to the medium prior to the addition of FCCP, inhibited uncoupled pyruvate oxidation; the apparent KI was 0.8 mM. These results are consistent with the hypothesis that it is the intramitochondrial ATP/ADP ratio that is one of the controlling factors in determining the rate of flux through the tricarboxylate cycle. Changes in the mitochondrial content of citrate, isocitrate, alpha-ketoglutarate, and malate during uncoupled pyruvate oxidation in the presence of a limiting concentration of ADP were consistent with the hypothesis that the

  19. ERα36, a variant of estrogen receptor α, is predominantly localized in mitochondria of human uterine smooth muscle and leiomyoma cells.

    Directory of Open Access Journals (Sweden)

    Yitang Yan

    Full Text Available ERα36 is a naturally occurring, membrane-associated, isoform of estrogen receptor α. The expression of ERα36 is due to alternative splicing and different promoter usage. ERα36 is a dominant-negative effector of ERα66-mediated transactivational activities and has the potential to trigger membrane-initiated mitogenic, nongenomic, estrogen signaling; however, the subcellular localization of ERα36 remains controversial. To determine the cellular localization of ERα36 in estrogen-responsive human uterine smooth muscle (ht-UtSMC and leiomyoma (fibroid; ht-UtLM cells, we conducted systematic confocal microscopy and subcellular fractionation analysis using ERα36 antibodies. With Image J colocalizaton analysis plugin, confocal images were analyzed to obtain a Pearson's Correlation Coefficient (PCC to quantify signal colocalization of ERα36 with mitochondrial, endoplasmic reticulum, and cytoskeletal components in both cell lines. When cells were double-stained with an ERα36 antibody and a mitochondrial-specific dye, MitoTracker, the PCC for the two channel signals were both greater than 0.75, indicating strong correlation between ERα36 and mitochondrial signals in the two cell lines. A blocking peptide competition assay confirmed that the mitochondria-associated ERα36 signal detected by confocal analysis was specific for ERα36. In contrast, confocal images double-stained with an ERα36 antibody and endoplasmic reticulum or cytoskeletal markers, had PCCs that were all less than 0.4, indicating no or very weak signal correlation. Fractionation studies showed that ERα36 existed predominantly in membrane fractions, with minimal or undetected amounts in the cytosol, nuclear, chromatin, and cytoskeletal fractions. With isolated mitochondrial preparations, we confirmed that a known mitochondrial protein, prohibitin, was present in mitochondria, and by co-immunoprecipitation analysis that ERα36 was associated with prohibitin in ht-UtLM cells. The

  20. A BAX/BAK and cyclophilin D-independent intrinsic apoptosis pathway.

    Directory of Open Access Journals (Sweden)

    Sebastián Zamorano

    Full Text Available Most intrinsic death signals converge into the activation of pro-apoptotic BCL-2 family members BAX and BAK at the mitochondria, resulting in the release of cytochrome c and apoptosome activation. Chronic endoplasmic reticulum (ER stress leads to apoptosis through the upregulation of a subset of pro-apoptotic BH3-only proteins, activating BAX and BAK at the mitochondria. Here we provide evidence indicating that the full resistance of BAX and BAK double deficient (DKO cells to ER stress is reverted by stimulation in combination with mild serum withdrawal. Cell death under these conditions was characterized by the appearance of classical apoptosis markers, caspase-9 activation, release of cytochrome c, and was inhibited by knocking down caspase-9, but insensitive to BCL-X(L overexpression. Similarly, the resistance of BIM and PUMA double deficient cells to ER stress was reverted by mild serum withdrawal. Surprisingly, BAX/BAK-independent cell death did not require Cyclophilin D (CypD expression, an important regulator of the mitochondrial permeability transition pore. Our results suggest the existence of an alternative intrinsic apoptosis pathway emerging from a cross talk between the ER and the mitochondria.