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Sample records for plant mitochondria cytoplasmic

  1. 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.

  2. Pollen mitochondria in cytoplasmically male sterile tobacco zygotic and embryonic cells

    International Nuclear Information System (INIS)

    Symillides, Y.

    1985-09-01

    An attempt is being made to establish cytoplasmic organelles transmission during the process of fertilization, by using tobacco grain pollen labelled with leucine 14 C and tritiated thymidine. Through autoradiography the fate of pollen germination and its entry into the embryo sac has been studied. A few days after fertilization, labelled cytoplasmic organelles - mainly mitochondria - were detected in the embryo sac. However, labelling was not observed in cytoplasmic organelles by using tritiated thymidine. For more conclusive results labelled DNA incorporated in cytoplasmic organelles have to be traced during the embryo and endosperm development

  3. Binding of host-selective toxin analogs to mitochondria from normal and Texas male sterile cytoplasm maize

    International Nuclear Information System (INIS)

    Frantzen, K.A.; Daly, J.M.; Knoche, H.W.

    1987-01-01

    Tritium-labeled toxin analogs were prepared by reduction with NaB 3 H 4 of either the toxin from Helminthosporium maydis race T or a toxin component from Phyllosticta maydis. These reduced analogs had high radiochemical specific activities, high biological activities, and plant specificities identical to the native toxins. A filtration assay was developed to test the binding of these labeled analogs to isolated mitochondria. Binding was not energy dependent nor was there measurable matrical uptake. The analogs were shown to be lipophilic, a characteristic which gave rise to considerable nondisplaceable binding. Under conditions limiting nondisplaceable binding, the displaceable binding was shown to be linear with respect to toxin concentration and unsaturable. No significant differences were observed in the binding characteristics between the mitochondria from normal and male-sterile (Texas) cytoplasm maize. The findings suggest that, at physiologically relevant concentrations, these toxin analogs permeate the membranes of susceptible and resistant mitochondria alike. The lack of demonstrable specific binding does not rule out the involvement of a classical receptor site but does indicate that other kinds of molecular interactions may be involved in the mechanisms for toxicity and specificity

  4. Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

    Science.gov (United States)

    Peremyslov, Valera V; Cole, Rex A; Fowler, John E; Dolja, Valerian V

    2015-01-01

    Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

  5. 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....

  6. Cytoplasmic streaming velocity as a plant size determinant.

    Science.gov (United States)

    Tominaga, Motoki; Kimura, Atsushi; Yokota, Etsuo; Haraguchi, Takeshi; Shimmen, Teruo; Yamamoto, Keiichi; Nakano, Akihiko; Ito, Kohji

    2013-11-11

    Cytoplasmic streaming is active transport widely occurring in plant cells ranging from algae to angiosperms. Although it has been revealed that cytoplasmic streaming is generated by organelle-associated myosin XI moving along actin bundles, the fundamental function in plants remains unclear. We generated high- and low-speed chimeric myosin XI by replacing the motor domains of Arabidopsis thaliana myosin XI-2 with those of Chara corallina myosin XI and Homo sapiens myosin Vb, respectively. Surprisingly, the plant sizes of the transgenic Arabidopsis expressing high- and low-speed chimeric myosin XI-2 were larger and smaller, respectively, than that of the wild-type plant. This size change correlated with acceleration and deceleration, respectively, of cytoplasmic streaming. Our results strongly suggest that cytoplasmic streaming is a key determinant of plant size. Furthermore, because cytoplasmic streaming is a common system for intracellular transport in plants, our system could have applications in artificial size control in plants. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. 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...

  8. Hydrodynamic flow in the cytoplasm of plant cells.

    NARCIS (Netherlands)

    Esseling-Ozdoba, A.; Houtman, D.; Lammeren, A.A. van; Eiser, E.; Emons, A.M.C.

    2008-01-01

    Plant cells show myosin-driven organelle movement, called cytoplasmic streaming. Soluble molecules, such as metabolites do not move with motor proteins but by diffusion. However, is all of this streaming active motor-driven organelle transport? Our recent simulation study (Houtman et al., 2007)

  9. Hydrodynamic flow in the cytoplasm of plant cells

    NARCIS (Netherlands)

    Esseling-Ozdoba, A.; Houtman, D.; van Lammeren, A.A.M.; Eiser, E.; Emons, A.M.C.

    2008-01-01

    Plant cells show myosin-driven organelle movement, called cytoplasmic streaming. Soluble molecules, such as metabolites do not move with motor proteins but by diffusion. However, is all of this streaming active motor-driven organelle transport? Our recent simulation study (Houtman et al., 2007)

  10. Hydrodynamic flow in the cytoplasm of plant cells

    NARCIS (Netherlands)

    Esseling-Ozdoba, A.; Houtman, D.; Lammeren, van A.A.M.; Eiser, E.; Emons, A.M.C.

    2008-01-01

    Plant cells show myosin-driven organelle movement, called cytoplasmic streaming. Soluble molecules, such as metabolites do not move with motor proteins but by diffusion. However, is all of this streaming active motor-driven organelle transport? Our recent simulation study ( Houtman et al., 2007 )

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Actin and myosin regulate cytoplasm stiffness in plant cells: a study using optical tweezers

    NARCIS (Netherlands)

    Honing, van der H.S.; Ruijter, de N.C.A.; Emons, A.M.C.; Ketelaar, T.

    2010-01-01

    Here, we produced cytoplasmic protrusions with optical tweezers in mature BY-2 suspension cultured cells to study the parameters involved in the movement of actin filaments during changes in cytoplasmic organization and to determine whether stiffness is an actin-related property of plant cytoplasm.

  13. Prediction of Chlamydia pneumoniae protein localization in host mitochondria and cytoplasm and possible involvements in lung cancer etiology: a computational approach

    Directory of Open Access Journals (Sweden)

    Aws Alshamsan

    2017-12-01

    Full Text Available Collecting evidence suggests that the intercellular infection of Chlamydia pneumoniae in lungs contributes to the etiology of lung cancer. Many proteins of Chlamydia pneumoniae outmanoeuvre the various system of the host. The infection may regulate various factors, which can influence the growth of lung cancer in affected persons. In this in-silico study, we predict potential targeting of Chlamydia pneumoniae proteins in mitochondrial and cytoplasmic comportments of host cell and their possible involvement in growth and development of lung cancer. Various cellular activities are controlled in mitochondria and cytoplasm, where the localization of Chlamydia pneumoniae proteins may alter the normal functioning of host cells. The rationale of this study is to find out and explain the connection between Chlamydia pneumoniae infection and lung cancer. A sum of 183 and 513 proteins were predicted to target in mitochondria and cytoplasm of host cell out of total 1112 proteins of Chlamydia pneumoniae. In particular, many targeted proteins may interfere with normal growth behaviour of host cells, thereby altering the decision of program cell death. Present article provides a potential connection of Chlamydia pneumoniae protein targeting and proposed that various targeted proteins may play crucial role in lung cancer etiology through diverse mechanisms.

  14. 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.

  15. DNA maintenance in plastids and mitochondria of plants

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    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.

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

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    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.

  17. 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....

  18. 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.

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

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    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.

  20. In Vivo Imaging of Diacylglycerol at the Cytoplasmic Leaflet of Plant Membranes.

    Science.gov (United States)

    Vermeer, Joop E M; van Wijk, Ringo; Goedhart, Joachim; Geldner, Niko; Chory, Joanne; Gadella, Theodorus W J; Munnik, Teun

    2017-07-01

    Diacylglycerol (DAG) is an important intermediate in lipid biosynthesis and plays key roles in cell signaling, either as a second messenger itself or as a precursor of phosphatidic acid. Methods to identify distinct DAG pools have proven difficult because biochemical fractionation affects the pools, and concentrations are limiting. Here, we validate the use of a genetically encoded DAG biosensor in living plant cells. The sensor is composed of a fusion between yellow fluorescent protein and the C1a domain of protein kinase C (YFP-C1aPKC) that specifically binds DAG, and was stably expressed in suspension-cultured tobacco BY-2 cells and whole Arabidopsis thaliana plants. Confocal imaging revealed that the majority of the YFP-C1aPKC fluorescence did not locate to membranes but was present in the cytosol and nucleus. Treatment with short-chain DAG or PMA (phorbol-12-myristate-13-acetate), a phorbol ester that binds the C1a domain of PKC, caused the recruitment of the biosensor to the plasma membrane. These results indicate that the biosensor works and that the basal DAG concentration in the cytoplasmic leaflet of membranes (i.e. accessible to the biosensor) is in general too low, and confirms that the known pools in plastids, the endoplasmic reticulum and mitochondria are located at the luminal face of these compartments (i.e. inaccessible to the biosensor). Nevertheless, detailed further analysis of different cells and tissues discovered four novel DAG pools, namely at: (i) the trans-Golgi network; (ii) the cell plate during cytokinesis; (iii) the plasma membrane of root epidermal cells in the transition zone, and (iv) the apex of growing root hairs. The results provide new insights into the spatiotemporal dynamics of DAG in plants and offer a new tool to monitor this in vivo. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. 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.

  2. Mitochondria as a Possible Place for Initial Stages of Steroid Biosynthesis in Plants

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    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.

  3. Probing cytoplasmic organization and the actin cytoskeleton of plant cells with optical tweezers

    NARCIS (Netherlands)

    Ketelaar, T.; Honing, van der H.S.; Emons, A.M.C.

    2010-01-01

    In interphase plant cells, the actin cytoskeleton is essential for intracellular transport and organization. To fully understand how the actin cytoskeleton functions as the structural basis for cytoplasmic organization, both molecular and physical aspects of the actin organization have to be

  4. 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....

  5. Cytoplasmic Acidification and Secondary Metabolite Production in Different Plant Cell Suspensions (A Comparative Study).

    Science.gov (United States)

    Hagendoorn, MJM.; Wagner, A. M.; Segers, G.; Van Der Plas, LHW.; Oostdam, A.; Van Walraven, H. S.

    1994-10-01

    In this study, a correlation is described between low cytoplasmic pH, measured with the fluorescent probes 2[prime],7[prime]-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (acetoxymethyl ester) and bis- [3-propyl-5-oxoisoxazol-4-yl]pentamethine oxonol, and the production of secondary metabolites for several plant cell-suspension systems. Anthraquinone production in Morinda citrifolia suspensions is negligible in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D), whereas with naphthalene acetic acid (NAA) a significant accumulation is realized. NAA-grown cells showed a lower cytoplasmic pH than did 2,4-D-grown cells. Addition of 2,4-D or parachlorophenoxy acetic acid to NAA-grown cells resulted in an inhibition of anthraquinone production and an increase of the cytoplasmic pH, whereas addition of parachlorophenyl acetic acid had no effect on either parameter. Lignin production in Petunia hybrida cells could be induced by subculturing them in a medium without iron. These cells showed a lower cytoplasmic pH than control cells. Addition of Fe3+ led to a decreased lignin content and an increased cytoplasmic pH. Two cell lines of Linum flavum showed a different level of coniferin and lignin concentration in their cells. Cells that accumulated coniferin and lignin had a lower cytoplasmic pH than cells that did not accumulate these secondary metabolites. Apparently, in different species and after different kinds of treatment there is a correlation between acidification of the cytoplasm and the production of different secondary metabolites. The possible role of this acidification in secondary metabolite production is discussed.

  6. 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

  7. Plant vegetative and animal cytoplasmic actins share functional competence for spatial development with protists.

    Science.gov (United States)

    Kandasamy, Muthugapatti K; McKinney, Elizabeth C; Roy, Eileen; Meagher, Richard B

    2012-05-01

    Actin is an essential multifunctional protein encoded by two distinct ancient classes of genes in animals (cytoplasmic and muscle) and plants (vegetative and reproductive). The prevailing view is that each class of actin variants is functionally distinct. However, we propose that the vegetative plant and cytoplasmic animal variants have conserved functional competence for spatial development inherited from an ancestral protist actin sequence. To test this idea, we ectopically expressed animal and protist actins in Arabidopsis thaliana double vegetative actin mutants that are dramatically altered in cell and organ morphologies. We found that expression of cytoplasmic actins from humans and even a highly divergent invertebrate Ciona intestinalis qualitatively and quantitatively suppressed the root cell polarity and organ defects of act8 act7 mutants and moderately suppressed the root-hairless phenotype of act2 act8 mutants. By contrast, human muscle actins were unable to support prominently any aspect of plant development. Furthermore, actins from three protists representing Choanozoa, Archamoeba, and green algae efficiently suppressed all the phenotypes of both the plant mutants. Remarkably, these data imply that actin's competence to carry out a complex suite of processes essential for multicellular development was already fully developed in single-celled protists and evolved nonprogressively from protists to plants and animals.

  8. Plant cytoplasmic GAPDH: redox post-translational modifications and moonlighting properties

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    Mirko eZaffagnini

    2013-11-01

    Full Text Available Glyceraldehyde-3-phosphate dehydrogenase (GAPDH is a ubiquitous enzyme involved in glycolysis and shown, particularly in animal cells, to play additional roles in several unrelated non-metabolic processes such as control of gene expression and apoptosis. This functional versatility is regulated, in part at least, by redox post-translational modifications that alter GAPDH catalytic activity and influence the subcellular localization of the enzyme. In spite of the well established moonlighting (multifunctional properties of animal GAPDH, little is known about non-metabolic roles of GAPDH in plants. Plant cells contain several GAPDH isoforms with different catalytic and regulatory properties, located both in the cytoplasm and in plastids, and participating in glycolysis and the Calvin-Benson cycle. A general feature of all GAPDH proteins is the presence of an acidic catalytic cysteine in the active site that is overly sensitive to oxidative modifications, including glutathionylation and S-nitrosylation. In Arabidopsis, oxidatively-modified cytoplasmic GAPDH has been successfully used as a tool to investigate the role of reduced glutathione, thioredoxins and glutaredoxins in the control of different types of redox post-translational modifications. Oxidative modifications inhibit GAPDH activity, but might enable additional functions in plant cells. Mounting evidence support the concept that plant cytoplasmic GAPDH may fulfill alternative, non-metabolic functions that are triggered by redox post-translational modifications of the protein under stress conditions. The aim of this review is to detail the molecular mechanisms underlying the redox regulation of plant cytoplasmic GAPDH in the light of its crystal structure, and to provide a brief inventory of the well known redox-dependent multi-facetted properties of animal GAPDH, together with the emerging roles of oxidatively-modified GAPDH in stress signaling pathways in plants.

  9. 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

  10. The role of non-coding RNAs in cytoplasmic male sterility in flowering plants

    Czech Academy of Sciences Publication Activity Database

    Štorchová, Helena

    2017-01-01

    Roč. 18, č. 11 (2017), č. článku 2429. E-ISSN 1422-0067 R&D Projects: GA ČR GA16-09220S Institutional support: RVO:61389030 Keywords : Cytoplasmic male sterility * Gene expression * Global transcriptome * Non-coding RNA * Pollen development Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 3.226, year: 2016

  11. 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.

  12. 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

  13. The absence of A-to-I editing in the anticodon of plant cytoplasmic tRNA (Arg) ACG demands a relaxation of the wobble decoding rules.

    Science.gov (United States)

    Aldinger, Carolin A; Leisinger, Anne-Katrin; Gaston, Kirk W; Limbach, Patrick A; Igloi, Gabor L

    2012-10-01

    It is a prevalent concept that, in line with the Wobble Hypothesis, those tRNAs having an adenosine in the first position of the anticodon become modified to an inosine at this position. Sequencing the cDNA derived from the gene coding for cytoplasmic tRNA (Arg) ACG from several higher plants as well as mass spectrometric analysis of the isoacceptor has revealed that for this kingdom an unmodified A in the wobble position of the anticodon is the rule rather than the exception. In vitro translation shows that in the plant system the absence of inosine in the wobble position of tRNA (Arg) does not prevent decoding. This isoacceptor belongs to the class of tRNA that is imported from the cytoplasm into the mitochondria of higher plants. Previous studies on the mitochondrial tRNA pool have demonstrated the existence of tRNA (Arg) ICG in this organelle. In moss the mitochondrial encoded distinct tRNA (Arg) ACG isoacceptor possesses the I34 modification. The implication is that for mitochondrial protein biosynthesis A-to-I editing is necessary and occurs by a mitochondrion-specific deaminase after import of the unmodified nuclear encoded tRNA (Arg) ACG.

  14. The multiplicity of dehydrogenases in the electron transport chain of plant mitochondria

    DEFF Research Database (Denmark)

    Rasmusson, Allan G; Geisler, Daniela A; Møller, Ian Max

    2008-01-01

    The electron transport chain in mitochondria of different organisms contains a mixture of common and specialised components. The specialised enzymes form branches to the universal electron path, especially at the level of ubiquinone, and allow the chain to adjust to different cellular and metabolic...... and their consequences for the understanding of electron transport and redundancy of electron paths...... requirements. In plants, specialised components have been known for a long time. However, recently, the known number of plant respiratory chain dehydrogenases has increased, including both components specific to plants and those with mammalian counterparts. This review will highlight the novel branches...

  15. Cytological study of radiation induced alterations in cytoplasmic factors controlling male sterility in corn. Progress report, February 28, 1975--December 1, 1975

    International Nuclear Information System (INIS)

    Edwardson, J.R.

    1975-01-01

    Progress is reported on the following research projects: cytoplasmic constituents of the embryo of various gymnosperms and angiosperms; cytoplasmic male sterility in corn; modification of cytoplasmic sterility factors using gamma radiation, EMS, and ethidium bromide; selection for sterile, blight-resistant corn plants; electron microscopy study of abnormal mitochondria in cytoplasm of corn; cytoplasmic male sterility in Petunia; non-Mendelian variegation in Petunia and Nicotiana; graft transmission of cytoplasmic male sterility; cytoplasmic male sterility in Vicia faba; and studies on Blakeslee's I virus in Datura

  16. Reactive nitrogen species in mitochondria and their implications in plant energy status and hypoxic stress tolerance

    Directory of Open Access Journals (Sweden)

    Kapuganti Jagadis Gupta

    2016-03-01

    Full Text Available Hypoxic and anoxic conditions result in the energy crisis that leads to cell damage. Since mitochondria are the primary organelles for energy production, the support of these organelles in a functional state is an important task during oxygen deprivation. Plant mitochondria adapted the strategy to survive under hypoxia by keeping electron transport operative even without oxygen via the use of nitrite as a terminal electrons acceptor. The process of nitrite reduction to nitric oxide (NO in the mitochondrial electron transport chain recycles NADH and leads to a limited rate of ATP production. The produced ATP alongside with the ATP generated by fermentation supports the processes of transcription and translation required for hypoxic survival and recovery of plants. Non-symbiotic hemoglobins (called phytoglobins in plants scavenge NO and thus contribute to regeneration of NAD+ and nitrate required for the operation of anaerobic energy metabolism. This overall operation represents an important strategy of biochemical adaptation that results in the improvement of energy status and thereby in protection of plants in the conditions of hypoxic stress.

  17. Positive Selection Driving Cytoplasmic Genome Evolution of the Medicinally Important Ginseng Plant Genus Panax.

    Science.gov (United States)

    Jiang, Peng; Shi, Feng-Xue; Li, Ming-Rui; Liu, Bao; Wen, Jun; Xiao, Hong-Xing; Li, Lin-Feng

    2018-01-01

    Panax L. (the ginseng genus) is a shade-demanding group within the family Araliaceae and all of its species are of crucial significance in traditional Chinese medicine. Phylogenetic and biogeographic analyses demonstrated that two rounds of whole genome duplications accompanying with geographic and ecological isolations promoted the diversification of Panax species. However, contributions of the cytoplasmic genomes to the adaptive evolution of Panax species remained largely uninvestigated. In this study, we sequenced the chloroplast and mitochondrial genomes of 11 accessions belonging to seven Panax species. Our results show that heterogeneity in nucleotide substitution rate is abundant in both of the two cytoplasmic genomes, with the mitochondrial genome possessing more variants at the total level but the chloroplast showing higher sequence polymorphisms at the genic regions. Genome-wide scanning of positive selection identified five and 12 genes from the chloroplast and mitochondrial genomes, respectively. Functional analyses further revealed that these selected genes play important roles in plant development, cellular metabolism and adaptation. We therefore conclude that positive selection might be one of the potential evolutionary forces that shaped nucleotide variation pattern of these Panax species. In particular, the mitochondrial genes evolved under stronger selective pressure compared to the chloroplast genes.

  18. Cytoplasmic streaming in plant cells emerges naturally by microfilament self-organization.

    Science.gov (United States)

    Woodhouse, Francis G; Goldstein, Raymond E

    2013-08-27

    Many cells exhibit large-scale active circulation of their entire fluid contents, a process termed cytoplasmic streaming. This phenomenon is particularly prevalent in plant cells, often presenting strikingly regimented flow patterns. The driving mechanism in such cells is known: myosin-coated organelles entrain cytoplasm as they process along actin filament bundles fixed at the periphery. Still unknown, however, is the developmental process that constructs the well-ordered actin configurations required for coherent cell-scale flow. Previous experimental works on streaming regeneration in cells of Characean algae, whose longitudinal flow is perhaps the most regimented of all, hint at an autonomous process of microfilament self-organization driving the formation of streaming patterns during morphogenesis. Working from first principles, we propose a robust model of streaming emergence that combines motor dynamics with both microscopic and macroscopic hydrodynamics to explain how several independent processes, each ineffectual on its own, can reinforce to ultimately develop the patterns of streaming observed in the Characeae and other streaming species.

  19. The Pseudomonas syringae type III effector HopG1 targets mitochondria, alters plant development, and suppresses plant innate immunity

    Science.gov (United States)

    Block, Anna; Guo, Ming; Li, Guangyong; Elowsky, Christian; Clemente, Thomas E.; Alfano, James R.

    2009-01-01

    Summary The bacterial plant pathogen Pseudomonas syringae uses a type III protein secretion system to inject type III effectors into plant cells. Primary targets of these effectors appear to be effector-triggered immunity (ETI) and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). The type III effector HopG1 is a suppressor of ETI that is broadly conserved in bacterial plant pathogens. Here we show that HopG1 from P. syringae pv. tomato DC3000 also suppresses PTI. Interestingly, HopG1 localizes to plant mitochondria, suggesting that its suppression of innate immunity may be linked to a perturbation of mitochondrial function. While HopG1 possesses no obvious mitochondrial signal peptide, its N-terminal two-thirds was sufficient for mitochondrial localization. A HopG1-GFP fusion lacking HopG1’s N-terminal 13 amino acids was not localized to the mitochondria reflecting the importance of the N-terminus for targeting. Constitutive expression of HopG1 in Arabidopsis thaliana, Nicotiana tabacum (tobacco) and Lycopersicon esculentum (tomato) dramatically alters plant development resulting in dwarfism, increased branching and infertility. Constitutive expression of HopG1 in planta leads to reduced respiration rates and an increased basal level of reactive oxygen species. These findings suggest that HopG1’s target is mitochondrial and that effector/target interaction promotes disease by disrupting mitochondrial functions. PMID:19863557

  20. Balanced nuclear and cytoplasmic activities of EDS1 are required for a complete plant innate immune response.

    Directory of Open Access Journals (Sweden)

    Ana V García

    2010-07-01

    Full Text Available An important layer of plant innate immunity to host-adapted pathogens is conferred by intracellular nucleotide-binding/oligomerization domain-leucine rich repeat (NB-LRR receptors recognizing specific microbial effectors. Signaling from activated receptors of the TIR (Toll/Interleukin-1 Receptor-NB-LRR class converges on the nucleo-cytoplasmic immune regulator EDS1 (Enhanced Disease Susceptibility1. In this report we show that a receptor-stimulated increase in accumulation of nuclear EDS1 precedes or coincides with the EDS1-dependent induction and repression of defense-related genes. EDS1 is capable of nuclear transport receptor-mediated shuttling between the cytoplasm and nucleus. By enhancing EDS1 export from inside nuclei (through attachment of an additional nuclear export sequence (NES or conditionally releasing EDS1 to the nucleus (by fusion to a glucocorticoid receptor (GR in transgenic Arabidopsis we establish that the EDS1 nuclear pool is essential for resistance to biotrophic and hemi-biotrophic pathogens and for transcriptional reprogramming. Evidence points to post-transcriptional processes regulating receptor-triggered accumulation of EDS1 in nuclei. Changes in nuclear EDS1 levels become equilibrated with the cytoplasmic EDS1 pool and cytoplasmic EDS1 is needed for complete resistance and restriction of host cell death at infection sites. We propose that coordinated nuclear and cytoplasmic activities of EDS1 enable the plant to mount an appropriately balanced immune response to pathogen attack.

  1. Regulation of Cytoplasmic and Vacuolar Volumes by Plant Cells in Suspension Culture

    DEFF Research Database (Denmark)

    Owens, Trevor; Poole, Ronald J

    1979-01-01

    Quantitative microscopical measurements have been made of the proportion of cell volume occupied by cytoplasm in a cell suspension culture derived from cotyledons of bush bean (cv. Contender). On a 7-day culture cycle, the content of cytoplasm varies from 25% at the time of transfer to 45% at the...

  2. Analysis of genetic effects of nuclear-cytoplasmic interaction on quantitative traits: genetic model for diploid plants.

    Science.gov (United States)

    Han, Lide; Yang, Jian; Zhu, Jun

    2007-06-01

    A genetic model was proposed for simultaneously analyzing genetic effects of nuclear, cytoplasm, and nuclear-cytoplasmic interaction (NCI) as well as their genotype by environment (GE) interaction for quantitative traits of diploid plants. In the model, the NCI effects were further partitioned into additive and dominance nuclear-cytoplasmic interaction components. Mixed linear model approaches were used for statistical analysis. On the basis of diallel cross designs, Monte Carlo simulations showed that the genetic model was robust for estimating variance components under several situations without specific effects. Random genetic effects were predicted by an adjusted unbiased prediction (AUP) method. Data on four quantitative traits (boll number, lint percentage, fiber length, and micronaire) in Upland cotton (Gossypium hirsutum L.) were analyzed as a worked example to show the effectiveness of the model.

  3. Plant Vegetative and Animal Cytoplasmic Actins Share Functional Competence for Spatial Development with Protists[W][OA

    Science.gov (United States)

    Kandasamy, Muthugapatti K.; McKinney, Elizabeth C.; Roy, Eileen; Meagher, Richard B.

    2012-01-01

    Actin is an essential multifunctional protein encoded by two distinct ancient classes of genes in animals (cytoplasmic and muscle) and plants (vegetative and reproductive). The prevailing view is that each class of actin variants is functionally distinct. However, we propose that the vegetative plant and cytoplasmic animal variants have conserved functional competence for spatial development inherited from an ancestral protist actin sequence. To test this idea, we ectopically expressed animal and protist actins in Arabidopsis thaliana double vegetative actin mutants that are dramatically altered in cell and organ morphologies. We found that expression of cytoplasmic actins from humans and even a highly divergent invertebrate Ciona intestinalis qualitatively and quantitatively suppressed the root cell polarity and organ defects of act8 act7 mutants and moderately suppressed the root-hairless phenotype of act2 act8 mutants. By contrast, human muscle actins were unable to support prominently any aspect of plant development. Furthermore, actins from three protists representing Choanozoa, Archamoeba, and green algae efficiently suppressed all the phenotypes of both the plant mutants. Remarkably, these data imply that actin’s competence to carry out a complex suite of processes essential for multicellular development was already fully developed in single-celled protists and evolved nonprogressively from protists to plants and animals. PMID:22589468

  4. Novel nuclear-cytoplasmic interaction in wheat (Triticum aestivum) induces vigorous plants

    Science.gov (United States)

    Interspecific hybridization can be considered an accelerator of evolution, otherwise a slow process, solely dependent on mutation and recombination. Upon interspecific hybridization, several novel interactions between nuclear and cytoplasmic genomes emerge which provide additional sources of diversi...

  5. 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.

  6. Plant Rho-type (Rop) GTPase-dependent activation of receptor-like cytoplasmic kinases in vitro.

    Science.gov (United States)

    Dorjgotov, Dulguun; Jurca, Manuela E; Fodor-Dunai, Csilla; Szucs, Attila; Otvös, Krisztina; Klement, Eva; Bíró, Judit; Fehér, Attila

    2009-04-02

    Plants have evolved distinct mechanisms to link Rho-type (Rop) GTPases to downstream signaling pathways as compared to other eukaryotes. Here, experimental data are provided that members of the Medicago, as well as Arabidopsis, receptor-like cytoplasmic kinase family (RLCK Class VI) were strongly and specifically activated by GTP-bound Rop GTPases in vitro. Deletion analysis indicated that the residues implicated in the interaction might be distributed on various parts of the kinases. Using a chimaeric Rop GTPase protein, the importance of the Rho-insert region in kinase activation could also be verified. These data strengthen the possibility that RLCKs may serve as Rop GTPase effectors in planta.

  7. 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....

  8. Actin based processes that could determine the cytoplasmic architecture of plant cells

    NARCIS (Netherlands)

    Honing, van der H.S.; Emons, A.M.C.; Ketelaar, M.J.

    2007-01-01

    Actin polymerisation can generate forces that are necessary for cell movement, such as the propulsion of a class of bacteria, including Listeria, and the protrusion of migrating animal cells. Force generation by the actin cytoskeleton in plant cells has not been studied. One process in plant cells

  9. Origins of the plant chloroplasts and mitochondria based on comparisons of 5S ribosomal RNAs

    Science.gov (United States)

    Delihas, N.; Fox, G. E.

    1987-01-01

    In this paper, we provide macromolecular comparisons utilizing the 5S ribosomal RNA structure to suggest extant bacteria that are the likely descendants of chloroplast and mitochondria endosymbionts. The genetic stability and near universality of the 5S ribosomal gene allows for a useful means to study ancient evolutionary changes by macromolecular comparisons. The value in current and future ribosomal RNA comparisons is in fine tuning the assignment of ancestors to the organelles and in establishing extant species likely to be descendants of bacteria involved in presumed multiple endosymbiotic events.

  10. Heritable effect of plant water availability conditions on restoration of male fertility in the ‘9E’ CMS-inducing cytoplasm of sorghum

    Directory of Open Access Journals (Sweden)

    Lev Aleksandrovich Elkonin

    2012-05-01

    Full Text Available Heritable changes of phenotype arising in plant ontogenesis by the influence of environmental factors belong to the most intriguing genetic phenomena. Studying restoration of male fertility in the ‘9E’ type of CMS-inducing cytoplasm of sorghum and related CMS-inducing cytoplasms, A4 and M35-1A, in some hybrid combinations, we found an unusual inheritance pattern: the Rf-genes functioned in the self-pollinated progenies of F1 hybrids (up to F10 but did not or poorly expressed in backcrosses of these hybrids to CMS-lines with the same cytoplasm type. In experiments on parallel growing of the same F1 hybrid combinations in the ‘dry plot’ and in the ‘irrigated plot’, it was found that high level of plant water availability during panicle and pollen developmental stages significantly increased male fertility of F1 and testcross hybrid populations, in which fertility-restoring genes were in heterozygote state, whereas in F2 populations the influences of water availability conditions cause less pronounce effects. Similarly, male-sterile F1 plants, being transferred from the ‘dry plot’ to greenhouse, produced male-fertile panicles. In addition, male-sterile plants from F2 families, which segregated-out as recessives, being transferred to greenhouse also produced male-fertile panicles. In the progenies of these revertants that were grown in field conditions and in the ‘dry plot’, stable inheritance of male fertility for 3 cycles of self-pollination was observed, and a number of stable fertile lines in the ‘9E’ cytoplasm were obtained. However, in test-crosses of these fertile lines to CMS-lines with the ‘9E’ cytoplasm restoration of male fertility was not observed, except the progeny of one revertant that behaved as fertility-restorer line. These data suggest that the functional state of fertility-restoring genes for the ‘9E’ sorghum cytoplasm is epigenetically-regulated trait established by the influence of environmental

  11. Expression of the nuclear gene TaF(A)d is under mitochondrial retrograde regulation in anthers of male sterile wheat plants with timopheevii cytoplasm.

    Science.gov (United States)

    Xu, Pei; Yang, Yuwen; Zhang, Zhengzhi; Chen, Weihua; Zhang, Caiqin; Zhang, Lixia; Zou, Sixiang; Ma, Zhengqiang

    2008-01-01

    Alterations of mitochondrial-encoded subunits of the F(o)F(1)-ATP synthase are frequently associated with cytoplasmic male sterility (CMS) in plants; however, little is known about the relationship of the nuclear encoded subunits of this enzyme with CMS. In the present study, the full cDNA of the gene TaF(A)d that encodes the putative F(A)d subunit of the F(o)F(1)-ATP synthase was isolated from the wheat (Triticum aestivum) fertility restorer '2114' for timopheevii cytoplasm-based CMS. The deduced 238 amino acid polypeptide is highly similar to its counterparts in dicots and other monocots but has low homology to its mammalian equivalents. TaF(A)d is a single copy gene in wheat and maps to the short arm of the group 6 chromosomes. Transient expression of the TaF(A)d-GFP fusion in onion epidermal cells demonstrated TaF(A)d's mitochondrial location. TaF(A)d was expressed abundantly in stem, leaf, anther, and ovary tissues of 2114. Nevertheless, its expression was repressed in anthers of CMS plants with timopheevii cytoplasm. Genic male sterility did not affect its expression in anthers. The expression of the nuclear gene encoding the 20 kDa subunit of F(o) was down-regulated in a manner similar to TaF(A)d in the T-CMS anthers while that of genes encoding the 6 kDa subunit of F(o) and the gamma subunit of F(1) was unaffected. These observations implied that TaF(A)d is under mitochondrial retrograde regulation in the anthers of CMS plants with timopheevii cytoplasm.

  12. Transcript Lifetime Is Balanced between Stabilizing Stem-Loop Structures and Degradation-Promoting Polyadenylation in Plant Mitochondria

    Science.gov (United States)

    Kuhn, Josef; Tengler, Ulrike; Binder, Stefan

    2001-01-01

    To determine the influence of posttranscriptional modifications on 3′ end processing and RNA stability in plant mitochondria, pea atp9 and Oenothera atp1 transcripts were investigated for the presence and function of 3′ nonencoded nucleotides. A 3′ rapid amplification of cDNA ends approach initiated at oligo(dT)-adapter primers finds the expected poly(A) tails predominantly attached within the second stem or downstream of the double stem-loop structures at sites of previously mapped 3′ ends. Functional studies in a pea mitochondrial in vitro processing system reveal a rapid removal of the poly(A) tails up to termini at the stem-loop structure but little if any influence on further degradation of the RNA. In contrast 3′ poly(A) tracts at RNAs without such stem-loop structures significantly promote total degradation in vitro. To determine the in vivo identity of 3′ nonencoded nucleotides more accurately, pea atp9 transcripts were analyzed by a direct anchor primer ligation-reverse transcriptase PCR approach. This analysis identified maximally 3-nucleotide-long nonencoded extensions most frequently of adenosines combined with cytidines. Processing assays with substrates containing homopolymer stretches of different lengths showed that 10 or more adenosines accelerate RNA processivity, while 3 adenosines have no impact on RNA life span. Thus polyadenylation can generally stimulate the decay of RNAs, but processivity of degradation is almost annihilated by the stabilizing effect of the stem-loop structures. These antagonistic actions thus result in the efficient formation of 3′ processed and stable transcripts. PMID:11154261

  13. The Cytoplasmic Carbonic Anhydrases βCA2 and βCA4 Are Required for Optimal Plant Growth at Low CO2.

    Science.gov (United States)

    DiMario, Robert J; Quebedeaux, Jennifer C; Longstreth, David J; Dassanayake, Maheshi; Hartman, Monica M; Moroney, James V

    2016-05-01

    Carbonic anhydrases (CAs) are zinc metalloenzymes that interconvert CO2 and HCO3 (-) In plants, both α- and β-type CAs are present. We hypothesize that cytoplasmic βCAs are required to modulate inorganic carbon forms needed in leaf cells for carbon-requiring reactions such as photosynthesis and amino acid biosynthesis. In this report, we present evidence that βCA2 and βCA4 are the two most abundant cytoplasmic CAs in Arabidopsis (Arabidopsis thaliana) leaves. Previously, βCA4 was reported to be localized to the plasma membrane, but here, we show that two forms of βCA4 are expressed in a tissue-specific manner and that the two proteins encoded by βCA4 localize to two different regions of the cell. Comparing transfer DNA knockout lines with wild-type plants, there was no reduction in the growth rates of the single mutants, βca2 and βca4 However, the growth rate of the double mutant, βca2βca4, was reduced significantly when grown at 200 μL L(-1) CO2 The reduction in growth of the double mutant was not linked to a reduction in photosynthetic rate. The amino acid content of leaves from the double mutant showed marked reduction in aspartate when compared with the wild type and the single mutants. This suggests the cytoplasmic CAs play an important but not previously appreciated role in amino acid biosynthesis. © 2016 American Society of Plant Biologists. All Rights Reserved.

  14. Complete genome sequence and integrated protein localization and interaction map for alfalfa dwarf virus, which combines properties of both cytoplasmic and nuclear plant rhabdoviruses

    Energy Technology Data Exchange (ETDEWEB)

    Bejerman, Nicolás, E-mail: n.bejerman@uq.edu.au [Instituto de Patología Vegetal (IPAVE), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria INTA, Camino a 60 Cuadras k 5,5, Córdoba X5020ICA (Argentina); Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD 4072 (Australia); Giolitti, Fabián; Breuil, Soledad de; Trucco, Verónica; Nome, Claudia; Lenardon, Sergio [Instituto de Patología Vegetal (IPAVE), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria INTA, Camino a 60 Cuadras k 5,5, Córdoba X5020ICA (Argentina); Dietzgen, Ralf G. [Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD 4072 (Australia)

    2015-09-15

    Summary: We have determined the full-length 14,491-nucleotide genome sequence of a new plant rhabdovirus, alfalfa dwarf virus (ADV). Seven open reading frames (ORFs) were identified in the antigenomic orientation of the negative-sense, single-stranded viral RNA, in the order 3′-N-P-P3-M-G-P6-L-5′. The ORFs are separated by conserved intergenic regions and the genome coding region is flanked by complementary 3′ leader and 5′ trailer sequences. Phylogenetic analysis of the nucleoprotein amino acid sequence indicated that this alfalfa-infecting rhabdovirus is related to viruses in the genus Cytorhabdovirus. When transiently expressed as GFP fusions in Nicotiana benthamiana leaves, most ADV proteins accumulated in the cell periphery, but unexpectedly P protein was localized exclusively in the nucleus. ADV P protein was shown to have a homotypic, and heterotypic nuclear interactions with N, P3 and M proteins by bimolecular fluorescence complementation. ADV appears unique in that it combines properties of both cytoplasmic and nuclear plant rhabdoviruses. - Highlights: • The complete genome of alfalfa dwarf virus is obtained. • An integrated localization and interaction map for ADV is determined. • ADV has a genome sequence similarity and evolutionary links with cytorhabdoviruses. • ADV protein localization and interaction data show an association with the nucleus. • ADV combines properties of both cytoplasmic and nuclear plant rhabdoviruses.

  15. Complete genome sequence and integrated protein localization and interaction map for alfalfa dwarf virus, which combines properties of both cytoplasmic and nuclear plant rhabdoviruses

    International Nuclear Information System (INIS)

    Bejerman, Nicolás; Giolitti, Fabián; Breuil, Soledad de; Trucco, Verónica; Nome, Claudia; Lenardon, Sergio; Dietzgen, Ralf G.

    2015-01-01

    Summary: We have determined the full-length 14,491-nucleotide genome sequence of a new plant rhabdovirus, alfalfa dwarf virus (ADV). Seven open reading frames (ORFs) were identified in the antigenomic orientation of the negative-sense, single-stranded viral RNA, in the order 3′-N-P-P3-M-G-P6-L-5′. The ORFs are separated by conserved intergenic regions and the genome coding region is flanked by complementary 3′ leader and 5′ trailer sequences. Phylogenetic analysis of the nucleoprotein amino acid sequence indicated that this alfalfa-infecting rhabdovirus is related to viruses in the genus Cytorhabdovirus. When transiently expressed as GFP fusions in Nicotiana benthamiana leaves, most ADV proteins accumulated in the cell periphery, but unexpectedly P protein was localized exclusively in the nucleus. ADV P protein was shown to have a homotypic, and heterotypic nuclear interactions with N, P3 and M proteins by bimolecular fluorescence complementation. ADV appears unique in that it combines properties of both cytoplasmic and nuclear plant rhabdoviruses. - Highlights: • The complete genome of alfalfa dwarf virus is obtained. • An integrated localization and interaction map for ADV is determined. • ADV has a genome sequence similarity and evolutionary links with cytorhabdoviruses. • ADV protein localization and interaction data show an association with the nucleus. • ADV combines properties of both cytoplasmic and nuclear plant rhabdoviruses

  16. Cooperation and competition between adenylate kinase, nucleoside diphosphokinase, electron transport, and ATP synthase in plant mitochondria studied by 31P-nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Roberts, J.K.M.; Aubert, S.; Gout, E.; Bligny, R.; Douce, R.

    1997-01-01

    Nucleotide metabolism in potato (Solanum tuberosum) mitochondria was studied using 31P-nuclear magnetic resonance spectroscopy and the O2 electrode. Immediately following the addition of ADP, ATP synthesis exceeded the rate of oxidative phosphorylation, fueled by succinate oxidation, due to mitochondrial adenylate kinase (AK) activity two to four times the maximum activity of ATP synthase. Only when the AK reaction approached equilibrium was oxidative phosphorylation the primary mechanism for net ATP synthesis. A pool of sequestered ATP in mitochondria enabled AK and ATP synthase to convert AMP to ATP in the presence of exogenous inorganic phosphate. During this conversion, AK activity can indirectly influence rates of oxidation of both succinate and NADH via changes in mitochondrial ATP. Mitochondrial nucleoside diphosphokinase, in cooperation with ATP synthase, was found to facilitate phosphorylation of nucleoside diphosphates other than ADP at rates similar to the maximum rate of oxidative phosphorylation. These results demonstrate that plant mitochondria contain all of the machinery necessary to rapidly regenerate nucleoside triphosphates from AMP and nucleoside diphosphates made during cellular biosynthesis and that AK activity can affect both the amount of ADP available to ATP synthase and the level of ATP regulating electron transport

  17. A rice chloroplast transit peptide sequence does not alter the cytoplasmic localization of sheep serotonin N-acetyltransferase expressed in transgenic rice plants.

    Science.gov (United States)

    Byeon, Yeong; Lee, Hyoung Yool; Lee, Kyungjin; Back, Kyoungwhan

    2014-09-01

    Ectopic overexpression of melatonin biosynthetic genes of animal origin has been used to generate melatonin-rich transgenic plants to examine the functional roles of melatonin in plants. However, the subcellular localization of these proteins expressed in the transgenic plants remains unknown. We studied the localization of sheep (Ovis aries) serotonin N-acetyltransferase (OaSNAT) and a translational fusion of a rice SNAT transit peptide to OaSNAT (TS:OaSNAT) in plants. Laser confocal microscopy analysis revealed that both OaSNAT and TS:OaSNAT proteins were localized to the cytoplasm even with the addition of the transit sequence to OaSNAT. Transgenic rice plants overexpressing the TS:OaSNAT fusion transgene exhibited high SNAT enzyme activity relative to untransformed wild-type plants, but lower activity than transgenic rice plants expressing the wild-type OaSNAT gene. Melatonin levels in both types of transgenic rice plant corresponded well with SNAT enzyme activity levels. The TS:OaSNAT transgenic lines exhibited increased seminal root growth relative to wild-type plants, but less than in the OaSNAT transgenic lines, confirming that melatonin promotes root growth. Seed-specific OaSNAT expression under the control of a rice prolamin promoter did not confer high levels of melatonin production in transgenic rice seeds compared with seeds from transgenic plants expressing OaSNAT under the control of the constitutive maize ubiquitin promoter. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Cytoplasniic differentiation during microsporogenesis in higher plants

    Directory of Open Access Journals (Sweden)

    H. Dichinnson

    2014-01-01

    Full Text Available Conspicuous cytoplasmic dedifferentiation in the pollen mother cells takes place early in the meiotic prophase of many plants. This event involves the removal of much of the cytoplasmic RNA. and the differentiation of both plastids and mitochondria to approaching the sole expression of their genomes. Much of the RNA removed from the cytoplasm passes to the nucleoplasm where it is utilised in the construction of a new `generation' of ribusomes. These new ribosomes are incorporated into cytoplasmic `nuclewhich disintegrate in the post-meiotic cytoplasm, restoring its ribosomes to pre-prophase levels. These changes are interpreted as evidence of a process by which the cytoplasm is cleansed of sporophytic control elements, both for the expression of the new gametophytic genome, and in the female cells of higher plants, for transmission to the new generation. The absence of control elements (presumably long-term messenger RNA from the cytoplasm would result in the dedifferentiation observed in the organelles, and the low levels of reserves in these cells presumably results in characteristically lengthy and unusual redifferentiation of both plastids and mitochondria, once information-carrying molecules again enter the cytosol.

  19. Beet yellow stunt virus in cells of Sonchus oleraceus L. and its relation to host mitochondria.

    Science.gov (United States)

    Esau, K

    1979-10-15

    In Sonchus oleraceus L. (Asteraceae) infected with the beet yellow stunt virus (BYSV) the virions are found in phloem cells, including the sieve elements. In parenchymatous phloem cells, the virus is present mainly in the cytoplasm. In some parenchymatous cells, containing massive accumulations of virus, the flexuous rodlike virus particles are found partly inserted into mitochondrial cristae. The mitochondrial envelope is absent where virus is present in the cristae. A similar relation between virus and host mitochondria apparently has not been recorded for any other plant virus.

  20. 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.

  1. 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...

  2. 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.

  3. Metabolic reconstructions identify plant 3-methylglutaconyl-CoA hydratase that is crucial for branched-chain amino acid catabolism in mitochondria.

    Science.gov (United States)

    Latimer, Scott; Li, Yubing; Nguyen, Thuong T H; Soubeyrand, Eric; Fatihi, Abdelhak; Elowsky, Christian G; Block, Anna; Pichersky, Eran; Basset, Gilles J

    2018-05-09

    The proteinogenic branched-chain amino acids (BCAAs) leucine, isoleucine and valine are essential nutrients for mammals. In plants, BCAAs double as alternative energy sources when carbohydrates become limiting, the catabolism of BCAAs providing electrons to the respiratory chain and intermediates to the tricarboxylic acid cycle. Yet, the actual architecture of the degradation pathways of BCAAs is not well understood. In this study, gene network modeling in Arabidopsis and rice, and plant-prokaryote comparative genomics detected candidates for 3-methylglutaconyl-CoA hydratase (4.2.1.18), one of the missing plant enzymes of leucine catabolism. Alignments of these protein candidates sampled from various spermatophytes revealed non-homologous N-terminal extensions that are lacking in their bacterial counterparts, and green fluorescent protein-fusion experiments demonstrated that the Arabidopsis protein, product of gene At4g16800, is targeted to mitochondria. Recombinant At4g16800 catalyzed the dehydration of 3-hydroxymethylglutaryl-CoA into 3-methylglutaconyl-CoA, and displayed kinetic features similar to those of its prokaryotic homolog. When at4g16800 knockout plants were subjected to dark-induced carbon starvation, their rosette leaves displayed accelerated senescence as compared to control plants, and this phenotype was paralleled by a marked increase in the accumulation of free and total leucine, isoleucine and valine. The seeds of the at4g16800 mutant showed a similar accumulation of free BCAAs. These data suggest that 3-methylglutaconyl-CoA hydratase is not solely involved in the degradation of leucine, but is also a significant contributor to that of isoleucine and valine. Furthermore, evidence is shown that unlike the situation observed in Trypanosomatidae, leucine catabolism does not contribute to the formation of the terpenoid precursor mevalonate. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights

  4. Cytoplasmic Streaming - Skylab Student Experiment ED-63

    Science.gov (United States)

    1973-01-01

    This chart describes the Skylab student experiment (ED-63), Cytoplasmic Streaming, proposed by Cheryl A. Peitz of Arapahoe High School, Littleton, Colorado. Experiment ED-63 was to observe the effect of zero-gravity on cytoplasmic streaming in the aquatic plant named Elodea, commonly called water weed or water thyme. The phenomenon of cytoplasmic streaming is not well understood, but it is recognized as the circulation mechanism of the internal materials or cytoplasm of a cell. Cytoplasm is a gelatinous substance that has the ability to change its viscosity and flow, carrying various cell materials with it. The activity can be stimulated by sunlight or heat. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  5. Interaction of plant cell signaling molecules, salicylic acid and jasmonic acid, with the mitochondria of Helicoverpa armigera.

    Science.gov (United States)

    Akbar, S M D; Sharma, H C; Jayalakshmi, S K; Sreeramulu, K

    2012-02-01

    The cotton bollworm, Helicoverpa armigera is a polyphagous pest in Asia, Africa, and the Mediterranean Europe. Salicylic acid (SA) and jasmonic acid (JA) are the cell signaling molecules produced in response to insect attack in plants. The effect of these signaling molecules was investigated on the oxidative phosphorylation and oxidative stress of H. armigera. SA significantly inhibited the state III and state IV respiration, respiratory control index (RCI), respiratory complexes I and II, induced mitochondrial swelling, and cytochrome c release in vitro. Under in vivo conditions, SA induced state IV respiration as well as oxidative stress in time- and dose-dependent manner, and also inhibited the larval growth. In contrast, JA did not affect the mitochondrial respiration and oxidative stress. SA affected the growth and development of H. armigera, in addition to its function as signaling molecules involved in both local defense reactions at feeding sites and the induction of systemic acquired resistance in plants.

  6. The molecular mechanism and physiological role of cytoplasmic streaming.

    Science.gov (United States)

    Tominaga, Motoki; Ito, Kohji

    2015-10-01

    Cytoplasmic streaming occurs widely in plants ranging from algae to angiosperms. However, the molecular mechanism and physiological role of cytoplasmic streaming have long remained unelucidated. Recent molecular genetic approaches have identified specific myosin members (XI-2 and XI-K as major and XI-1, XI-B, and XI-I as minor motive forces) for the generation of cytoplasmic streaming among 13 myosin XIs in Arabidopsis thaliana. Simultaneous knockout of these myosin XI members led to a reduced velocity of cytoplasmic streaming and marked defects of plant development. Furthermore, the artificial modifications of myosin XI-2 velocity changed plant and cell sizes along with the velocity of cytoplasmic streaming. Therefore, we assume that cytoplasmic streaming is one of the key regulators in determining plant size. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. 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

  8. Plant cyclopeptide RA-V kills human breast cancer cells by inducing mitochondria-mediated apoptosis through blocking PDK1–AKT interaction

    International Nuclear Information System (INIS)

    Fang, Xian-Ying; Chen, Wei; Fan, Jun-Ting; Song, Ran; Wang, Lu; Gu, Yan-Hong; Zeng, Guang-Zhi; Shen, Yan; Wu, Xue-Feng; Tan, Ning-Hua; Xu, Qiang; Sun, Yang

    2013-01-01

    In the present paper, we examined the effects of a natural cyclopeptide RA-V on human breast cancer cells and the underlying mechanisms. RA-V significantly inhibited the growth of human breast cancer MCF-7, MDA-MB-231 cells and murine breast cancer 4T1 cells. In addition, RA-V triggered mitochondrial apoptotic pathway which was indicated by the loss of mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase cascade. Further study showed that RA-V dramatically inhibited phosphorylation of AKT and 3-phosphoinositide dependent protein kinase 1 (PDK1) in MCF-7 cells. Moreover, RA-V disrupted the interaction between PDK1 and AKT in MCF-7 cells. Furthermore, RA-V-induced apoptosis could be enhanced by phosphatidylinositol 3-kinase inhibitor or attenuated by over-expression of AKT in all the three kinds of breast cancer cells. Taken together, this study shows that RA-V, which can induce mitochondria-mediated apoptosis, exerts strong anti-tumor activity against human breast cancer. The underlying anti-cancer mechanism of RA-V is related to the blockage of the interaction between PDK1 and AKT. - Highlights: ► Plant cyclopeptide RA-V kills human breast cancer cells. ► RA-V triggered mitochondrial apoptotic pathway in human breast cancer cells. ► RA-V inhibited phosphorylation of AKT and PDK1 in breast cancer MCF-7 cells. ► Its mechanism is related to the blockage of the interaction between PDK1 and AKT

  9. Plant cyclopeptide RA-V kills human breast cancer cells by inducing mitochondria-mediated apoptosis through blocking PDK1–AKT interaction

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xian-Ying; Chen, Wei [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing (China); Fan, Jun-Ting [State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming (China); Song, Ran; Wang, Lu [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing (China); Gu, Yan-Hong [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Zeng, Guang-Zhi [State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming (China); Shen, Yan; Wu, Xue-Feng [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing (China); Tan, Ning-Hua, E-mail: nhtan@mail.kib.ac.cn [State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming (China); Xu, Qiang, E-mail: molpharm@163.com [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing (China); Sun, Yang, E-mail: yangsun@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing (China)

    2013-02-15

    In the present paper, we examined the effects of a natural cyclopeptide RA-V on human breast cancer cells and the underlying mechanisms. RA-V significantly inhibited the growth of human breast cancer MCF-7, MDA-MB-231 cells and murine breast cancer 4T1 cells. In addition, RA-V triggered mitochondrial apoptotic pathway which was indicated by the loss of mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase cascade. Further study showed that RA-V dramatically inhibited phosphorylation of AKT and 3-phosphoinositide dependent protein kinase 1 (PDK1) in MCF-7 cells. Moreover, RA-V disrupted the interaction between PDK1 and AKT in MCF-7 cells. Furthermore, RA-V-induced apoptosis could be enhanced by phosphatidylinositol 3-kinase inhibitor or attenuated by over-expression of AKT in all the three kinds of breast cancer cells. Taken together, this study shows that RA-V, which can induce mitochondria-mediated apoptosis, exerts strong anti-tumor activity against human breast cancer. The underlying anti-cancer mechanism of RA-V is related to the blockage of the interaction between PDK1 and AKT. - Highlights: ► Plant cyclopeptide RA-V kills human breast cancer cells. ► RA-V triggered mitochondrial apoptotic pathway in human breast cancer cells. ► RA-V inhibited phosphorylation of AKT and PDK1 in breast cancer MCF-7 cells. ► Its mechanism is related to the blockage of the interaction between PDK1 and AKT.

  10. RNA editing makes mistakes in plant mitochondria: editing loses sense in transcripts of a rps19 pseudogene and in creating stop codons in coxI and rps3 mRNAs of Oenothera.

    Science.gov (United States)

    Schuster, W; Brennicke, A

    1991-01-01

    An intact gene for the ribosomal protein S19 (rps19) is absent from Oenothera mitochondria. The conserved rps19 reading frame found in the mitochondrial genome is interrupted by a termination codon. This rps19 pseudogene is cotranscribed with the downstream rps3 gene and is edited on both sides of the translational stop. Editing, however, changes the amino acid sequence at positions that were well conserved before editing. Other strange editings create translational stops in open reading frames coding for functional proteins. In coxI and rps3 mRNAs CGA codons are edited to UGA stop codons only five and three codons, respectively, downstream to the initiation codon. These aberrant editings in essential open reading frames and in the rps19 pseudogene appear to have been shifted to these positions from other editing sites. These observations suggest a requirement for a continuous evolutionary constraint on the editing specificities in plant mitochondria. Images PMID:1762921

  11. Uniparental Inheritance Promotes Adaptive Evolution in Cytoplasmic Genomes.

    Science.gov (United States)

    Christie, Joshua R; Beekman, Madeleine

    2017-03-01

    Eukaryotes carry numerous asexual cytoplasmic genomes (mitochondria and plastids). Lacking recombination, asexual genomes should theoretically suffer from impaired adaptive evolution. Yet, empirical evidence indicates that cytoplasmic genomes experience higher levels of adaptive evolution than predicted by theory. In this study, we use a computational model to show that the unique biology of cytoplasmic genomes-specifically their organization into host cells and their uniparental (maternal) inheritance-enable them to undergo effective adaptive evolution. Uniparental inheritance of cytoplasmic genomes decreases competition between different beneficial substitutions (clonal interference), promoting the accumulation of beneficial substitutions. Uniparental inheritance also facilitates selection against deleterious cytoplasmic substitutions, slowing Muller's ratchet. In addition, uniparental inheritance generally reduces genetic hitchhiking of deleterious substitutions during selective sweeps. Overall, uniparental inheritance promotes adaptive evolution by increasing the level of beneficial substitutions relative to deleterious substitutions. When we assume that cytoplasmic genome inheritance is biparental, decreasing the number of genomes transmitted during gametogenesis (bottleneck) aids adaptive evolution. Nevertheless, adaptive evolution is always more efficient when inheritance is uniparental. Our findings explain empirical observations that cytoplasmic genomes-despite their asexual mode of reproduction-can readily undergo adaptive evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  12. Uniparental Inheritance Promotes Adaptive Evolution in Cytoplasmic Genomes

    Science.gov (United States)

    Christie, Joshua R.; Beekman, Madeleine

    2017-01-01

    Eukaryotes carry numerous asexual cytoplasmic genomes (mitochondria and plastids). Lacking recombination, asexual genomes should theoretically suffer from impaired adaptive evolution. Yet, empirical evidence indicates that cytoplasmic genomes experience higher levels of adaptive evolution than predicted by theory. In this study, we use a computational model to show that the unique biology of cytoplasmic genomes—specifically their organization into host cells and their uniparental (maternal) inheritance—enable them to undergo effective adaptive evolution. Uniparental inheritance of cytoplasmic genomes decreases competition between different beneficial substitutions (clonal interference), promoting the accumulation of beneficial substitutions. Uniparental inheritance also facilitates selection against deleterious cytoplasmic substitutions, slowing Muller’s ratchet. In addition, uniparental inheritance generally reduces genetic hitchhiking of deleterious substitutions during selective sweeps. Overall, uniparental inheritance promotes adaptive evolution by increasing the level of beneficial substitutions relative to deleterious substitutions. When we assume that cytoplasmic genome inheritance is biparental, decreasing the number of genomes transmitted during gametogenesis (bottleneck) aids adaptive evolution. Nevertheless, adaptive evolution is always more efficient when inheritance is uniparental. Our findings explain empirical observations that cytoplasmic genomes—despite their asexual mode of reproduction—can readily undergo adaptive evolution. PMID:28025277

  13. 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

  14. Cytoplasmic male sterility of rice with boro II cytoplasm is caused by a cytotoxic peptide and is restored by two related PPR motif genes via distinct modes of mRNA silencing.

    Science.gov (United States)

    Wang, Zhonghua; Zou, Yanjiao; Li, Xiaoyu; Zhang, Qunyu; Chen, Letian; Wu, Hao; Su, Dihua; Chen, Yuanling; Guo, Jingxin; Luo, Da; Long, Yunming; Zhong, Yang; Liu, Yao-Guang

    2006-03-01

    Cytoplasmic male sterility (CMS) and nucleus-controlled fertility restoration are widespread plant reproductive features that provide useful tools to exploit heterosis in crops. However, the molecular mechanism underlying this kind of cytoplasmic-nuclear interaction remains unclear. Here, we show in rice (Oryza sativa) with Boro II cytoplasm that an abnormal mitochondrial open reading frame, orf79, is cotranscribed with a duplicated atp6 (B-atp6) gene and encodes a cytotoxic peptide. Expression of orf79 in CMS lines and transgenic rice plants caused gametophytic male sterility. Immunoblot analysis showed that the ORF79 protein accumulates specifically in microspores. Two fertility restorer genes, Rf1a and Rf1b, were identified at the classical locus Rf-1 as members of a multigene cluster that encode pentatricopeptide repeat proteins. RF1A and RF1B are both targeted to mitochondria and can restore male fertility by blocking ORF79 production via endonucleolytic cleavage (RF1A) or degradation (RF1B) of dicistronic B-atp6/orf79 mRNA. In the presence of both restorers, RF1A was epistatic over RF1B in the mRNA processing. We have also shown that RF1A plays an additional role in promoting the editing of atp6 mRNAs, independent of its cleavage function.

  15. 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...

  16. Cytoplasmic Z-RNA

    International Nuclear Information System (INIS)

    Zarling, D.A.; Calhoun, C.J.; Hardin, C.C.; Zarling, A.H.

    1987-01-01

    Specific immunochemical probes for Z-RNA were generated and characterized to search for possible Z-RNA-like double helices in cells. Z-RNA was detected in the cytoplasm of fixed protozoan cells by immunofluorescence microscopy using these anti-Z-RNA IgCs. In contrast, autoimmune or experimentally elicited anti-DNA antibodies, specifically reactive with B-DNA or Z-DNA, stained the nuclei. Pre-or nonimmune IgGs did not bind to the cells. RNase A or T1 digestion eliminated anti-Z-RNA IgG binding to cytoplasmic determinants; however, DNase I or mung bean nuclease had no effect. Doxorubicin and ethidium bromide prevented anti-Z-RNA antibody binding; however, actinomycin D, which does not bind double-stranded RNA, did not. Anti-Z-RNA immunofluorescence was specifically blocked in competition assays by synthetic Z-RNA but not Z-DNA, A-RNA, or single-stranded RNAs. Thus, some cytoplasmic sequences in fixed cells exist in the left-handed Z-RNA conformation

  17. Transcripts of the NADH-dehydrogenase subunit 3 gene are differentially edited in Oenothera mitochondria.

    Science.gov (United States)

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

    1990-01-01

    A number of cytosines are altered to be recognized as uridines in transcripts of the nad3 locus in mitochondria of the higher plant Oenothera. Such nucleotide modifications can be found at 16 different sites within the nad3 coding region. Most of these alterations in the mRNA sequence change codon identities to specify amino acids better conserved in evolution. Individual cDNA clones differ in their degree of editing at five nucleotide positions, three of which are silent, while two lead to codon alterations specifying different amino acids. None of the cDNA clones analysed is maximally edited at all possible sites, suggesting slow processing or lowered stringency of editing at these nucleotides. Differentially edited transcripts could be editing intermediates or could code for differing polypeptides. Two edited nucleotides in an open reading frame located upstream of nad3 change two amino acids in the deduced polypeptide. Part of the well-conserved ribosomal protein gene rps12 also encoded downstream of nad3 in other plants, is lost in Oenothera mitochondria by recombination events. The functional rps12 protein must be imported from the cytoplasm since the deleted sequences of this gene are not found in the Oenothera mitochondrial genome. The pseudogene sequence is not edited at any nucleotide position. Images Fig. 3. Fig. 4. Fig. 7. PMID:1688531

  18. Cytoplasmic Streaming in the Drosophila Oocyte.

    Science.gov (United States)

    Quinlan, Margot E

    2016-10-06

    Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.

  19. 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.

  20. 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...

  1. 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.

  2. 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

  3. Cytoplasmic Male Sterility of Rice with Boro II Cytoplasm Is Caused by a Cytotoxic Peptide and Is Restored by Two Related PPR Motif Genes via Distinct Modes of mRNA Silencing[W

    Science.gov (United States)

    Wang, Zhonghua; Zou, Yanjiao; Li, Xiaoyu; Zhang, Qunyu; Chen, Letian; Wu, Hao; Su, Dihua; Chen, Yuanling; Guo, Jingxin; Luo, Da; Long, Yunming; Zhong, Yang; Liu, Yao-Guang

    2006-01-01

    Cytoplasmic male sterility (CMS) and nucleus-controlled fertility restoration are widespread plant reproductive features that provide useful tools to exploit heterosis in crops. However, the molecular mechanism underlying this kind of cytoplasmic–nuclear interaction remains unclear. Here, we show in rice (Oryza sativa) with Boro II cytoplasm that an abnormal mitochondrial open reading frame, orf79, is cotranscribed with a duplicated atp6 (B-atp6) gene and encodes a cytotoxic peptide. Expression of orf79 in CMS lines and transgenic rice plants caused gametophytic male sterility. Immunoblot analysis showed that the ORF79 protein accumulates specifically in microspores. Two fertility restorer genes, Rf1a and Rf1b, were identified at the classical locus Rf-1 as members of a multigene cluster that encode pentatricopeptide repeat proteins. RF1A and RF1B are both targeted to mitochondria and can restore male fertility by blocking ORF79 production via endonucleolytic cleavage (RF1A) or degradation (RF1B) of dicistronic B-atp6/orf79 mRNA. In the presence of both restorers, RF1A was epistatic over RF1B in the mRNA processing. We have also shown that RF1A plays an additional role in promoting the editing of atp6 mRNAs, independent of its cleavage function. PMID:16489123

  4. 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

  5. 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.

  6. 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...

  7. 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.

  8. Cytoplasmic influence of nucleolar development

    International Nuclear Information System (INIS)

    Ghosh, Sibdas

    1974-01-01

    The role of cytoplasmic factors on the development of nucleolus in nucleus has been investigated in Ehrlich mouse ascites tumour cells using tritiated thymidine/uridine for autoradiography. It is inferred from the observations that the cytoplasmic factors has some but not absolute control over the development of nucleolus. (M.G.B.)

  9. 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

  10. 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.

  11. 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.

  12. Cellular Subcompartments through Cytoplasmic Streaming.

    Science.gov (United States)

    Pieuchot, Laurent; Lai, Julian; Loh, Rachel Ann; Leong, Fong Yew; Chiam, Keng-Hwee; Stajich, Jason; Jedd, Gregory

    2015-08-24

    Cytoplasmic streaming occurs in diverse cell types, where it generally serves a transport function. Here, we examine streaming in multicellular fungal hyphae and identify an additional function wherein regimented streaming forms distinct cytoplasmic subcompartments. In the hypha, cytoplasm flows directionally from cell to cell through septal pores. Using live-cell imaging and computer simulations, we identify a flow pattern that produces vortices (eddies) on the upstream side of the septum. Nuclei can be immobilized in these microfluidic eddies, where they form multinucleate aggregates and accumulate foci of the HDA-2 histone deacetylase-associated factor, SPA-19. Pores experiencing flow degenerate in the absence of SPA-19, suggesting that eddy-trapped nuclei function to reinforce the septum. Together, our data show that eddies comprise a subcellular niche favoring nuclear differentiation and that subcompartments can be self-organized as a consequence of regimented cytoplasmic streaming. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Genetic expression of induced rice sterility under alien-cytoplasm

    International Nuclear Information System (INIS)

    Wang Naiyuan; Cai Zhijun; Liang Kangjing; Li Yu

    2005-01-01

    Rice restorer lines were treated with 60 Co γ-ray and 4 male sterile mutants obtained with the fertility of controlled by 4 non-allelic recessive genes, respectively. Sixty combinations were made by using male sterile plants/fertile plants as male parents, and 15 different cytoplasmic substitution lines of the same cell nucleus as female parents. The result showed that F 1 spikelets were normal and fertile, and different numbers of male sterile plants were segregated in F 2 . Complete fertility genotype was not found among interactions between induced male sterile genes and alien-cytoplasms. (authors)

  14. 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

  15. 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.

  16. 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.

  17. The application of GBS markers for extending the dense genetic map of rye (Secale cereale L.) and the localization of the Rfc1 gene restoring male fertility in plants with the C source of sterility-inducing cytoplasm.

    Science.gov (United States)

    Milczarski, Paweł; Hanek, Monika; Tyrka, Mirosław; Stojałowski, Stefan

    2016-11-01

    Genotyping by sequencing (GBS) is an efficient method of genotyping in numerous plant species. One of the crucial steps toward the application of GBS markers in crop improvement is anchoring them on particular chromosomes. In rye (Secale cereale L.), chromosomal localization of GBS markers has not yet been reported. In this paper, the application of GBS markers generated by the DArTseq platform for extending the high-density map of rye is presented. Additionally, their application is used for the localization of the Rfc1 gene that restores male fertility in plants with the C source of sterility-inducing cytoplasm. The total number of markers anchored on the current version of the map is 19,081, of which 18,132 were obtained from the DArTseq platform. Numerous markers co-segregated within the studied mapping population, so, finally, only 3397 unique positions were located on the map of all seven rye chromosomes. The total length of the map is 1593 cM and the average distance between markers is 0.47 cM. In spite of the resolution of the map being not very high, it should be a useful tool for further studies of the Secale cereale genome because of the presence on this map of numerous GBS markers anchored for the first time on rye chromosomes. The Rfc1 gene was located on high-density maps of the long arm of the 4R chromosome obtained for two mapping populations. Genetic maps were composed of DArT, DArTseq, and PCR-based markers. Consistent mapping results were obtained and DArTs tightly linked to the Rfc1 gene were successfully applied for the development of six new PCR-based markers useful in marker-assisted selection.

  18. 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.

  19. Induction of cytoplasmic male sterility by gamma-ray and chemical mutagens in sugar beets

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Toshiro [Hokkaido Univ., Sapporo (Japan). Faculty of Agriculture

    1982-03-01

    Male sterile plants appeared in the population of N cytoplasm sugar beet strains, H-19 and H-2002, when their dry seeds were exposed to 50 kR gamma-ray, and the male sterility was maintained up to the M/sub 4/ generation through the mother plants. Cytoplasmic inheritance was confirmed by the reciprocal crossings between plants with normal phenotype from gamma-strains (progeneis of the male mutants which transmitted male sterility through the mother plants) and H-19 or H-1001. The crossing experiments suggested that various kinds of cytoplasm were induced by gamma-ray irradiation, and that different nuclear genes were responsible for the respective cytoplasms. A specific relationship between the pollen restoring genes and the sterile cytoplasms was established, and was named ''one set of pollen restoring genes for one cytoplasm''. It is probable that the cytoplasmic mutation occurred in normal cytoplasm strains and the specific combination between the altered cytoplasm and the recessive nuclear gene produced male sterility. Ethyl methane sulphonate, ethidium bromide, acriflavine and streptomycin were also effective in inducing cytoplasmic mutation in sugar beets.

  20. Induction of cytoplasmic male sterility by gamma-ray and chemical mutagens in sugar beets

    International Nuclear Information System (INIS)

    Kinoshita, Toshiro

    1982-01-01

    Male sterile plants appeared in the population of N cytoplasm sugar beet strains, H-19 and H-2002, when their dry seeds were exposed to 50 kR gamma-ray, and the male sterility was maintained up to the M 4 generation through the mother plants. Cytoplasmic inheritance was confirmed by the reciprocal crossings between plants with normal phenotype from gamma-strains (progeneis of the male mutants which transmitted male sterility through the mother plants) and H-19 or H-1001. The crossing experiments suggested that various kinds of cytoplasm were induced by gamma-ray irradiation, and that different nuclear genes were responsible for the respective cytoplasms. A specific relationship between the pollen restoring genes and the sterile cytoplasms was established, and was named ''one set of pollen restoring genes for one cytoplasm''. It is probable that the cytoplasmic mutation occurred in normal cytoplasm strains and the specific combination between the altered cytoplasm and the recessive nuclear gene produced male sterility. Ethyl methane sulphonate, ethidium bromide, acriflavine and streptomycin were also effective in inducing cytoplasmic mutation in sugar beets. (Kaihara, S.)

  1. 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...

  2. 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.

  3. Metabolic reconstructions identify plant 3-methylglutaconyl-CoA hydratase that is crucial for branched-chain amino acid catabolism in mitochondria

    Science.gov (United States)

    The proteinogenic branched-chain amino acids (BCAAs) leucine, isoleucine, and valine are essential nutrients for mammals. In plants, they double as alternative energy sources when carbohydrates become limiting, the catabolism of BCAAs providing electrons to the respiratory chain and intermediates...

  4. A potyvirus vector efficiently targets recombinant proteins to chloroplasts, mitochondria and nuclei in plant cells when expressed at the amino terminus of the polyprotein.

    Science.gov (United States)

    Majer, Eszter; Navarro, José-Antonio; Daròs, José-Antonio

    2015-09-01

    Plant virus-based expression systems allow quick and efficient production of recombinant proteins in plant biofactories. Among them, a system derived from tobacco etch virus (TEV; genus potyvirus) permits coexpression of equimolar amounts of several recombinant proteins. This work analyzed how to target recombinant proteins to different subcellular localizations in the plant cell using this system. We constructed TEV clones in which green fluorescent protein (GFP), with a chloroplast transit peptide (cTP), a nuclear localization signal (NLS) or a mitochondrial targeting peptide (mTP) was expressed either as the most amino-terminal product or embedded in the viral polyprotein. Results showed that cTP and mTP mediated efficient translocation of GFP to the corresponding organelle only when present at the amino terminus of the viral polyprotein. In contrast, the NLS worked efficiently at both positions. Viruses expressing GFP in the amino terminus of the viral polyprotein produced milder symptoms. Untagged GFPs and cTP and NLS tagged amino-terminal GFPs accumulated to higher amounts in infected tissues. Finally, viral progeny from clones with internal GFPs maintained the extra gene better. These observations will help in the design of potyvirus-based vectors able to coexpress several proteins while targeting different subcellular localizations, as required in plant metabolic engineering. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Role of mitochondria in modulation of spontaneous Ca2+ waves in freshly dispersed interstitial cells of Cajal from the rabbit urethra.

    Science.gov (United States)

    Sergeant, Gerard P; Bradley, Eamonn; Thornbury, Keith D; McHale, Noel G; Hollywood, Mark A

    2008-10-01

    Interstitial cells of Cajal (ICC) isolated from the rabbit urethra exhibit pacemaker activity that results from spontaneous Ca(2+) waves. The purpose of this study was to investigate if this activity was influenced by Ca(2+) uptake into mitochondria. Spontaneous Ca(2+) waves were recorded using a Nipkow spinning disk confocal microscope and spontaneous transient inward currents (STICs) were recorded using the whole-cell patch clamp technique. Disruption of the mitochondrial membrane potential with the electron transport chain inhibitors rotenone (10 microm) and antimycin A (5 microm) abolished Ca(2+) waves and increased basal Ca(2+) levels. Similar results were achieved when mitochondria membrane potential was collapsed using the protonophores FCCP (0.2 microm) and CCCP (1 microm). Spontaneous Ca(2+) waves were not inhibited by the ATP synthase inhibitor oligomycin (1 microm), suggesting that these effects were not attributable to an effect on ATP levels. STICs recorded under voltage clamp at -60 mV were also inhibited by CCCP and antimycin A. Dialysis of cells with the mitochondrial uniporter inhibitor RU360 (10 microm) also inhibited STICS. Stimulation of Ca(2+) uptake into mitochondria using the plant flavonoid kaempferol (10 microm) induced a series of propagating Ca(2+) waves. The kaempferol-induced activity was inhibited by application of caffeine (10 mm) or removal of extracellular Ca(2+), but was not significantly affected by the IP(3) receptor blocker 2-APB (100 microm). These data suggest that spontaneous Ca(2+) waves in urethral ICC are regulated by buffering of cytoplasmic Ca(2+) by mitochondria.

  10. 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

  11. 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.

  12. Labeling of Complex III peptides in beef heart mitochondria and submitochondrial particles by diazonium bensene [35S]sulfonate

    International Nuclear Information System (INIS)

    Mendel-Hartvig, I.; Nelson, B.D.

    1978-01-01

    The labeling of Complex III peptides in DABS-treated mitochondria and submitochondrial particles from beef heart is reported. The results are consistent with the labeling of the two core proteins on the matrix surface of the inner membrane, and of a 29 000 molecular weight peptide on the cytoplasmic surface. (Auth.)

  13. Transgenic expression of an unedited mitochondrial orfB gene product from wild abortive (WA) cytoplasm of rice (Oryza sativa L.) generates male sterility in fertile rice lines.

    Science.gov (United States)

    Chakraborty, Anirban; Mitra, Joy; Bhattacharyya, Jagannath; Pradhan, Subrata; Sikdar, Narattam; Das, Srirupa; Chakraborty, Saikat; Kumar, Sachin; Lakhanpaul, Suman; Sen, Soumitra K

    2015-06-01

    Over-expression of the unedited mitochondrial orfB gene product generates male sterility in fertile indica rice lines in a dose-dependent manner. Cytoplasmic male sterility (CMS) and nuclear-controlled fertility restoration are widespread developmental features in plant reproductive systems. In self-pollinated crop plants, these processes often provide useful tools to exploit hybrid vigour. The wild abortive CMS has been employed in the majority of the "three-line" hybrid rice production since 1970s. In the present study, we provide experimental evidence for a positive functional relationship between the 1.1-kb unedited orfB gene transcript, and its translated product in the mitochondria with male sterility. The generation of the 1.1-kb unedited orfB gene transcripts increased during flowering, resulting in low ATP synthase activity in sterile plants. Following insertion of the unedited orfB gene into the genome of male-fertile plants, the plants became male sterile in a dose-dependent manner with concomitant reduction of ATPase activity of F1F0-ATP synthase (complex V). Fertility of the transgenic lines and normal activity of ATP synthase were restored by down-regulation of the unedited orfB gene expression through RNAi-mediated silencing. The genetic elements deciphered in this study could further be tested for their use in hybrid rice development.

  14. 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.

  15. 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

  16. 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

  17. 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...

  18. Whole Mitochondrial Genome Sequencing and Re-Examination of a Cytoplasmic Male Sterility-Associated Gene in Boro-Taichung-Type Cytoplasmic Male Sterile Rice.

    Science.gov (United States)

    Kazama, Tomohiko; Toriyama, Kinya

    2016-01-01

    Nuclear genome substitutions between subspecies can lead to cytoplasmic male sterility (CMS) through incompatibility between nuclear and mitochondrial genomes. Boro-Taichung (BT)-type CMS rice was obtained by substituting the nuclear genome of Oryza sativa subsp. indica cultivar Chinsurah Boro II with that of Oryza sativa subsp. japonica cultivar Taichung 65. In BT-type CMS rice, the mitochondrial gene orf79 is associated with male sterility. A complete sequence of the Boro-type mitochondrial genome responsible for BT-type CMS has not been determined to date. Here, we used pyrosequencing to construct the Boro-type mitochondrial genome. The contiguous sequences were assembled into five circular DNA molecules, four of which could be connected into a single circle. The two resulting subgenomic circles were unable to form a reliable master circle, as recombination between them was scarcely detected. We also found an unequal abundance of DNA molecules for the two loci of atp6. These results indicate the presence of multi-partite DNA molecules in the Boro-type mitochondrial genome. Expression patterns were investigated for Boro-type mitochondria-specific orfs, which were not found in the mitochondria from the standard japonica cultivar Nipponbare. Restorer of fertility 1 (RF1)-dependent RNA processing has been observed in orf79-containing RNA but was not detected in other Boro-type mitochondria-specific orfs, supporting the conclusion that orf79 is a unique CMS-associated gene in Boro-type mitochondria.

  19. Mechanisms for cytoplasmic organization: an overview.

    Science.gov (United States)

    Pagliaro, L

    2000-01-01

    One of the basic characteristics of life is the intrinsic organization of cytoplasm, yet we know surprisingly little about the manner in which cytoplasmic macromolecules are arranged. It is clear that cytoplasm is not the homogeneous "soup" it was once envisioned to be, but a comprehensive model for cytoplasmic organization is not available in modern cell biology. The premise of this volume is that phase separation in cytoplasm may play a role in organization at the subcellular level. Other mechanisms for non-membrane-bounded intracellular organization have previously been proposed. Some of these will be reviewed in this chapter. Multiple mechanisms, involving phase separation, specific intracellular targeting, formation of macromolecular complexes, and channeling, all could well contribute to cytoplasmic organization. Temporal and spatial organization, as well as composition, are likely to be important in defining the characteristics of cytoplasm.

  20. 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.

  1. Labelling of human resting lymphocytes by continuous infusion of (/sup 3/H)thymidine. 1. Characterization of cytoplasmic label

    Energy Technology Data Exchange (ETDEWEB)

    Schick, P; Trepel, F; Maisel, K H; Past, W; Reisert, I; Begemann, H; Pilgrim, C [Ulm Univ. (Germany, F.R.)

    1978-01-01

    After continuous /sup 3/H-TdR infusion in vivo or incubation with /sup 3/H-TdR in vitro human blood lymphocytes were examined by light-microscopic and electron-microscopic autoradiography. Using relatively long autoradiographic exposure times (50-300 days) not only nuclear but also cytoplasmic labelling was visualized, the cytoplasmic label being present in up to 96% of the cells. The cytoplasmic label was predominantly associated with the mitochondria and was removed from the cells nearly completely by treatment with DNase but not with RNase or cold perchloric acid. It is concluded that this cytoplasmic label mainly represents /sup 3/H-TdR incorporated into mitochondrial DNA which is continuously renewed in an average turnover time of 14 days or less. This value is compatible with a turnover time of 11 days for mitochondrial DNA in mammalian cells reported in the literature.

  2. Comparative analysis of mitochondrial genomes between a wheat K-type cytoplasmic male sterility (CMS) line and its maintainer line.

    Science.gov (United States)

    Liu, Huitao; Cui, Peng; Zhan, Kehui; Lin, Qiang; Zhuo, Guoyin; Guo, Xiaoli; Ding, Feng; Yang, Wenlong; Liu, Dongcheng; Hu, Songnian; Yu, Jun; Zhang, Aimin

    2011-03-29

    Plant mitochondria, semiautonomous organelles that function as manufacturers of cellular ATP, have their own genome that has a slow rate of evolution and rapid rearrangement. Cytoplasmic male sterility (CMS), a common phenotype in higher plants, is closely associated with rearrangements in mitochondrial DNA (mtDNA), and is widely used to produce F1 hybrid seeds in a variety of valuable crop species. Novel chimeric genes deduced from mtDNA rearrangements causing CMS have been identified in several plants, such as rice, sunflower, pepper, and rapeseed, but there are very few reports about mtDNA rearrangements in wheat. In the present work, we describe the mitochondrial genome of a wheat K-type CMS line and compare it with its maintainer line. The complete mtDNA sequence of a wheat K-type (with cytoplasm of Aegilops kotschyi) CMS line, Ks3, was assembled into a master circle (MC) molecule of 647,559 bp and found to harbor 34 known protein-coding genes, three rRNAs (18 S, 26 S, and 5 S rRNAs), and 16 different tRNAs. Compared to our previously published sequence of a K-type maintainer line, Km3, we detected Ks3-specific mtDNA (> 100 bp, 11.38%) and repeats (> 100 bp, 29 units) as well as genes that are unique to each line: rpl5 was missing in Ks3 and trnH was absent from Km3. We also defined 32 single nucleotide polymorphisms (SNPs) in 13 protein-coding, albeit functionally irrelevant, genes, and predicted 22 unique ORFs in Ks3, representing potential candidates for K-type CMS. All these sequence variations are candidates for involvement in CMS. A comparative analysis of the mtDNA of several angiosperms, including those from Ks3, Km3, rice, maize, Arabidopsis thaliana, and rapeseed, showed that non-coding sequences of higher plants had mostly divergent multiple reorganizations during the mtDNA evolution of higher plants. The complete mitochondrial genome of the wheat K-type CMS line Ks3 is very different from that of its maintainer line Km3, especially in non

  3. Comparative analysis of mitochondrial genomes between a wheat K-type cytoplasmic male sterility (CMS line and its maintainer line

    Directory of Open Access Journals (Sweden)

    Liu Dongcheng

    2011-03-01

    Full Text Available Abstract Background Plant mitochondria, semiautonomous organelles that function as manufacturers of cellular ATP, have their own genome that has a slow rate of evolution and rapid rearrangement. Cytoplasmic male sterility (CMS, a common phenotype in higher plants, is closely associated with rearrangements in mitochondrial DNA (mtDNA, and is widely used to produce F1 hybrid seeds in a variety of valuable crop species. Novel chimeric genes deduced from mtDNA rearrangements causing CMS have been identified in several plants, such as rice, sunflower, pepper, and rapeseed, but there are very few reports about mtDNA rearrangements in wheat. In the present work, we describe the mitochondrial genome of a wheat K-type CMS line and compare it with its maintainer line. Results The complete mtDNA sequence of a wheat K-type (with cytoplasm of Aegilops kotschyi CMS line, Ks3, was assembled into a master circle (MC molecule of 647,559 bp and found to harbor 34 known protein-coding genes, three rRNAs (18 S, 26 S, and 5 S rRNAs, and 16 different tRNAs. Compared to our previously published sequence of a K-type maintainer line, Km3, we detected Ks3-specific mtDNA (> 100 bp, 11.38% and repeats (> 100 bp, 29 units as well as genes that are unique to each line: rpl5 was missing in Ks3 and trnH was absent from Km3. We also defined 32 single nucleotide polymorphisms (SNPs in 13 protein-coding, albeit functionally irrelevant, genes, and predicted 22 unique ORFs in Ks3, representing potential candidates for K-type CMS. All these sequence variations are candidates for involvement in CMS. A comparative analysis of the mtDNA of several angiosperms, including those from Ks3, Km3, rice, maize, Arabidopsis thaliana, and rapeseed, showed that non-coding sequences of higher plants had mostly divergent multiple reorganizations during the mtDNA evolution of higher plants. Conclusion The complete mitochondrial genome of the wheat K-type CMS line Ks3 is very different from that of

  4. Tissue specific structural variations of mitochondria of fish ectoparasite Argulus bengalensis Ramakrishna, 1951 (Crustacea: Branchiura: Functional implications

    Directory of Open Access Journals (Sweden)

    Anirban Banerjee

    2014-05-01

    Full Text Available We studied the fine structure of some classical and six variant mitochondria from different tissues viz. proboscis gland, spinal gland, ovary, testis, and muscle of a fish ectoparasite, Argulus bengalensis. In the proboscis gland and spinal gland, mitochondria are protected within vesicle to preserve their structure and activity from exposure to glandular synthesis for its parasitic mode of feeding. In the oocytes, mitochondria are larger and cylindrical in appearance. Oocyte mitochondria are highly dynamic and exhibit frequent fission and fusion. Those are clustered in the cytoplasm of previtellogenic oocytes which prepare for different synthetic activities for successful reproductive investment. In contrast, mitochondrial abundance is less in the male gametic lineage. The spermatocytes and the nurse cells in the testis have an unusual type of mitochondria, nebenkern which is formed by the fusions of number of mitochondria. A completely different type of mitochondrion is discovered in the flagellum of the spermatozoa. It is provided with fifteen numbers of singlet microtubules at its outer periphery which is a salient feature of the flagellum of this Branchiuran genus. This unique mitochondrion uses the microtubule tract for its movement to distribute energy efficiently along the axoneme. Such mitochondrion and microtubular association provide evidence in favor of phylogenetic relationship between Argulus and pentastomid Raillietiella. In striated muscle of thoracic appendages, mitochondria maintain tight junctions with the endoplasmic reticulum and remain in close apposition of the myofibrils which helps in Ca2+ uptake for stimulating continuous muscular activity required for ventilation of respiratory structures of the parasites.

  5. A physical perspective on cytoplasmic streaming.

    Science.gov (United States)

    Goldstein, Raymond E; van de Meent, Jan-Willem

    2015-08-06

    Organisms show a remarkable range of sizes, yet the dimensions of a single cell rarely exceed 100 µm. While the physical and biological origins of this constraint remain poorly understood, exceptions to this rule give valuable insights. A well-known counterexample is the aquatic plant Chara, whose cells can exceed 10 cm in length and 1 mm in diameter. Two spiralling bands of molecular motors at the cell periphery drive the cellular fluid up and down at speeds up to 100 µm s(-1), motion that has been hypothesized to mitigate the slowness of metabolite transport on these scales and to aid in homeostasis. This is the most organized instance of a broad class of continuous motions known as 'cytoplasmic streaming', found in a wide range of eukaryotic organisms-algae, plants, amoebae, nematodes and flies-often in unusually large cells. In this overview of the physics of this phenomenon, we examine the interplay between streaming, transport and cell size and discuss the possible role of self-organization phenomena in establishing the observed patterns of streaming.

  6. Genetic variation among the male sterile cytoplasms induced by gamma irradiation in sugar beets

    International Nuclear Information System (INIS)

    Mikami, Tetsuo; Kinoshita, Toshiro; Takahashi, Man-emon

    1976-01-01

    In sugar beets, cytoplasmic male sterility was induced artificially by radiation treatment. In the present study, four kinds of male sterile strain made from the strain H-2002 with normal cytoplasms were used, and the mode of inheritance of the sterility maintained by these strains was confirmed. Also the hereditary mechanism of pollen fructification recovery was studied, and the newly induced heterotypic property of sterile cytoplasms was examined in comparison with naturally found sterile strains. In each of four produced strains, the male sterility was inherited down to M 4 lines stably through mother plants, and it was presumed that the sterility was caused by highly stable cytoplasmic mutation. In each strain, two pairs of nuclear genes took part in the recovery of pollen fructification, but the mode of action of two genes was different. As the result of mating for verification with O type strain to S cytoplasm strain, it seemed that at least the function as O type was not shown to three strains of γ-60, γ-114 and γ-165, and in the sterile cytoplasms of these three strains, the action of fructification recovery genes different from X and Z arose. It was presumed that the genes of X locus did not take effect in these induced cytoplasms. The possibility that at least four kinds of male sterile cytoplasms different from S were induced from normal cytoplasms by artificial mutation was proved indirectly. (Kako, I.)

  7. 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.

  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, 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

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. Characterization of cytoplasmic male sterility of rice with Lead Rice cytoplasm in comparison with that with Chinsurah Boro II cytoplasm.

    Science.gov (United States)

    Itabashi, Etsuko; Kazama, Tomohiko; Toriyama, Kinya

    2009-02-01

    Rice with LD-type cytoplasmic male sterility (CMS) possesses the cytoplasm of 'Lead Rice' and its fertility is recovered by a nuclear fertility restorer gene Rf1. Rf1 promotes processing of a CMS-associated mitochondrial RNA of atp6-orf79, which consists of atp6 and orf79, in BT-CMS with the cytoplasm of 'Chinsurah Boro II'. In this study, we found that LD-cytoplasm contained a sequence variant of orf79 downstream of atp6. Northern blot analysis showed that atp6-orf79 RNA of LD-cytoplasm was co-transcribed and was processed in the presence of Rf1 in the same manner as in BT-cytoplasm. Western blot analysis showed that the ORF79 peptide did not accumulate in an LD-CMS line, while ORF79 accumulated in a BT-CMS line and was diminished by Rf1. These results suggest that accumulation of ORF79 is not the cause of CMS in LD-cytoplasm and the mechanism of male-sterility induction/fertility restoration in LD-CMS is different from that in BT-CMS.

  15. 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.

  16. Hydrodynamic property of the cytoplasm is sufficient to mediate cytoplasmic streaming in the Caenorhabiditis elegans embryo

    Science.gov (United States)

    Niwayama, Ritsuya; Shinohara, Kyosuke; Kimura, Akatsuki

    2011-01-01

    Cytoplasmic streaming is a type of intracellular transport widely seen in nature. Cytoplasmic streaming in Caenorhabditis elegans at the one-cell stage is bidirectional; the flow near the cortex (“cortical flow”) is oriented toward the anterior, whereas the flow in the central region (“cytoplasmic flow”) is oriented toward the posterior. Both cortical flow and cytoplasmic flow depend on non-muscle-myosin II (NMY-2), which primarily localizes in the cortex. The manner in which NMY-2 proteins drive cytoplasmic flow in the opposite direction from remote locations has not been fully understood. In this study, we demonstrated that the hydrodynamic properties of the cytoplasm are sufficient to mediate the forces generated by the cortical myosin to drive bidirectional streaming throughout the cytoplasm. We quantified the flow velocities of cytoplasmic streaming using particle image velocimetry (PIV) and conducted a three-dimensional hydrodynamic simulation using the moving particle semiimplicit method. Our simulation quantitatively reconstructed the quantified flow velocity distribution resolved through PIV analysis. Furthermore, our PIV analyses detected microtubule-dependent flows during the pronuclear migration stage. These flows were reproduced via hydrodynamic interactions between moving pronuclei and the cytoplasm. The agreement of flow dynamics in vivo and in simulation indicates that the hydrodynamic properties of the cytoplasm are sufficient to mediate cytoplasmic streaming in C. elegans embryos. PMID:21730185

  17. Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

    DEFF Research Database (Denmark)

    Joseph, Bindu; Corwin, Jason A.; Li, Baohua

    2013-01-01

    Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes...... was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation...... in metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation....

  18. Dynamics of vegetative cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana

    Science.gov (United States)

    Kuang, A.; Musgrave, M. E.

    1996-01-01

    Ultrastructural changes of pollen cytoplasm during generative cell formation and pollen maturation in Arabidopsis thaliana were studied. The pollen cytoplasm develops a complicated ultrastructure and changes dramatically during these stages. Lipid droplets increase after generative cell formation and their organization and distribution change with the developmental stage. Starch grains in amyloplasts increase in number and size during generative and sperm cell formation and decrease at pollen maturity. The shape and membrane system of mitochondria change only slightly. Dictyosomes become very prominent, and numerous associated vesicles are observed during and after sperm cell formation. Endoplasmic reticulum appears extensively as stacks during sperm cell formation. Free and polyribosomes are abundant in the cytoplasm at all developmental stages although they appear denser at certain stages and in some areas. In mature pollen, all organelles are randomly distributed throughout the vegetative cytoplasm and numerous small particles appear. Organization and distribution of storage substances and appearance of these small particles during generative and sperm cell formation and pollen maturation are discussed.

  19. 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...

  20. 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.

  1. Molecular characterization of cytoplasmic male sterility (CMS) in perennial ryegrass ( Lolium perenne L.)

    DEFF Research Database (Denmark)

    Islam, Md. Shofiqul; Møller, Ian Max; Studer, Bruno

    2011-01-01

    to increase biomass yield, improve nutritional value and tolerance towards abiotic and biotic stress. Cytoplasmic male sterility (CMS) is an efficient tool to control pollination for hybrid seed production. In order to identify the causative polymorphism of the CMS phenotype, a cytoplasmic male sterile plant...

  2. 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

  3. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    instances of curious sex ratios exemplify an important principle: the fitness ..... markable transition - the whole means of sex determination has changed. No longer ... to the cytoplasmic symbiont is self-evident; the symbionts simply increase the.

  4. 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

  5. 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.

  6. Ultrastructural and biochemical evidence for the presence of mature steroidogenic acute regulatory protein (StAR) in the cytoplasm of human luteal cells.

    Science.gov (United States)

    Sierralta, Walter D; Kohen, Paulina; Castro, Olga; Muñoz, Alex; Strauss, Jerome F; Devoto, Luigi

    2005-10-20

    The distribution of the steroidogenic acute regulatory protein (StAR) inside thecal and granulosa-lutein cells of human corpus luteum (CL) was assessed by immunoelectron microscopy. We found greater levels of StAR immunolabeling in steroidogenic cells from early- and mid-than in late luteal phase CL and lower levels in cells from women treated with a GnRH antagonist in the mid-luteal phase. Immunoelectron microscopy revealed significant levels of StAR antigen in the mitochondria and in the cytoplasm of luteal cells. The 30 kDa mature StAR protein was present in both mitochondria and cytosol (post-mitochondrial) fractions from homogenates of CL at different ages, whereas cytochrome c and mitochondrial HSP70 were detected only in the mitochondrial fraction. Therefore, we hypothesized that either appreciable processing of StAR 37 kDa pre-protein occurs outside the mitochondria, or mature StAR protein is selectively released into the cytoplasm after mitochondrial processing. The presence of mature StAR in the cytoplasm is consonant with the notion that StAR acts on the outer mitochondrial membrane to effect sterol import, and that StAR may interact with other cytoplasmic proteins involved in cholesterol metabolism, including hormone sensitive lipase.

  7. 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

  8. 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.

  9. Cytoplasmic male sterility (CMS) in hybrid breeding in field crops.

    Science.gov (United States)

    Bohra, Abhishek; Jha, Uday C; Adhimoolam, Premkumar; Bisht, Deepak; Singh, Narendra P

    2016-05-01

    A comprehensive understanding of CMS/Rf system enabled by modern omics tools and technologies considerably improves our ability to harness hybrid technology for enhancing the productivity of field crops. Harnessing hybrid vigor or heterosis is a promising approach to tackle the current challenge of sustaining enhanced yield gains of field crops. In the context, cytoplasmic male sterility (CMS) owing to its heritable nature to manifest non-functional male gametophyte remains a cost-effective system to promote efficient hybrid seed production. The phenomenon of CMS stems from a complex interplay between maternally-inherited (mitochondrion) and bi-parental (nucleus) genomic elements. In recent years, attempts aimed to comprehend the sterility-inducing factors (orfs) and corresponding fertility determinants (Rf) in plants have greatly increased our access to candidate genomic segments and the cloned genes. To this end, novel insights obtained by applying state-of-the-art omics platforms have substantially enriched our understanding of cytoplasmic-nuclear communication. Concomitantly, molecular tools including DNA markers have been implicated in crop hybrid breeding in order to greatly expedite the progress. Here, we review the status of diverse sterility-inducing cytoplasms and associated Rf factors reported across different field crops along with exploring opportunities for integrating modern omics tools with CMS-based hybrid breeding.

  10. 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

  11. Cadmium Disrupts Subcellular Organelles, Including Chloroplasts, Resulting in Melatonin Induction in Plants

    Directory of Open Access Journals (Sweden)

    Hyoung-Yool Lee

    2017-10-01

    Full Text Available Cadmium is a well-known elicitor of melatonin synthesis in plants, including rice. However, the mechanisms by which cadmium induces melatonin induction remain elusive. To investigate whether cadmium influences physical integrities in subcellular organelles, we treated tobacco leaves with either CdCl2 or AlCl3 and monitored the structures of subcellular organelles—such as chloroplasts, mitochondria, and the endoplasmic reticulum (ER—using confocal microscopic analysis. Unlike AlCl3 treatment, CdCl2 (0.5 mM treatment significantly disrupted chloroplasts, mitochondria, and ER. In theory, the disruption of chloroplasts enabled chloroplast-expressed serotonin N-acetyltransferase (SNAT to encounter serotonin in the cytoplasm, leading to the synthesis of N-acetylserotonin followed by melatonin synthesis. In fact, the disruption of chloroplasts by cadmium, not by aluminum, gave rise to a huge induction of melatonin in rice leaves, which suggests that cadmium-treated chloroplast disruption plays an important role in inducing melatonin in plants by removing physical barriers, such as chloroplast double membranes, allowing SNAT to gain access to the serotonin substrate enriched in the cytoplasm.

  12. Calcium controls the formation of vacuoles from mitochondria to regulate microspore development in wheat.

    Science.gov (United States)

    Li, Dong Xiao; Hu, Hai Yan; Li, Gan; Ru, Zhen Gang; Tian, Hui Qiao

    2017-09-01

    Potassium antimonite was used to investigate the localisation of calcium in developing wheat anthers to examine the relationship between Ca 2+ and pollen development. During anther development, calcium precipitate formation increased in anther wall cells prior to microspore mother cell meiosis and appeared in microspores, suggesting the presence of a calcium influx from anther wall cells into the locule. Initially, the precipitates in microspore cytoplasm primarily accumulated in the mitochondria and destroyed their inner membranes (cisterns) to become small vacuoles, which expanded and fused, ultimately becoming a large vacuole during microspore vacuolisation. After microspore division and large vacuole decomposition, many calcium precipitates again accumulated in the small vacuoles, indicating that calcium from the large vacuole moved back into the cytoplasm of bicellular pollen.

  13. 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.

  14. 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.

  15. 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.

  16. Identification of the TaBTF3 gene in wheat (Triticum aestivum L.) and the effect of its silencing on wheat chloroplast, mitochondria and mesophyll cell development.

    Science.gov (United States)

    Ma, Hong-Zhen; Liu, Guo-Qin; Li, Cheng-Wei; Kang, Guo-Zhang; Guo, Tian-Cai

    2012-10-05

    The full-length cDNA (882bp) and DNA (1742bp) sequences encoding a basic transcription factor 3, designated as TaBTF3, were first isolated from common wheat (Triticum aestivum L.). Subcellular localization studies revealed that the TaBTF3 protein was mainly located in the cytoplasm and nucleus. In TaBTF3-silenced transgenic wheat seedlings obtained using the Virus-induced gene silencing (VIGS) method, the chlorophyll pigment content was markedly reduced. However, the malonaldehyde (MDA) and H(2)O(2) contents were enhanced, and the structure of the wheat mesophyll cell was seriously damaged. Furthermore, transcripts of the chloroplast- and mitochondrial-encoded genes were significantly reduced in TaBTF3-silenced transgenic wheat plants. These results suggest that the TaBTF3 gene might function in the development of the wheat chloroplast, mitochondria and mesophyll cell. This paper is the first report to describe the involvement of TaBTF3 in maintaining the normal plant mesophyll cell structure. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. 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.

  18. Misfolded SOD1 associated with motor neuron mitochondria alters mitochondrial shape and distribution prior to clinical onset.

    Directory of Open Access Journals (Sweden)

    Christine Vande Velde

    Full Text Available Mutations in superoxide dismutase (SOD1 are causative for inherited amyotrophic lateral sclerosis. A proportion of SOD1 mutant protein is misfolded onto the cytoplasmic face of mitochondria in one or more spinal cord cell types. By construction of mice in which mitochondrially targeted enhanced green fluorescent protein is selectively expressed in motor neurons, we demonstrate that axonal mitochondria of motor neurons are primary in vivo targets for misfolded SOD1. Mutant SOD1 alters axonal mitochondrial morphology and distribution, with dismutase active SOD1 causing mitochondrial clustering at the proximal side of Schmidt-Lanterman incisures within motor axons and dismutase inactive SOD1 producing aberrantly elongated axonal mitochondria beginning pre-symptomatically and increasing in severity as disease progresses. Somal mitochondria are altered by mutant SOD1, with loss of the characteristic cylindrical, networked morphology and its replacement by a less elongated, more spherical shape. These data indicate that mutant SOD1 binding to mitochondria disrupts normal mitochondrial distribution and size homeostasis as early pathogenic features of SOD1 mutant-mediated ALS.

  19. Cytoplasmic Estrogen Receptor in breast cancer

    Science.gov (United States)

    Welsh, Allison W.; Lannin, Donald R.; Young, Gregory S.; Sherman, Mark E.; Figueroa, Jonine D.; Henry, N. Lynn; Ryden, Lisa; Kim, Chungyeul; Love, Richard R.; Schiff, Rachel; Rimm, David L.

    2011-01-01

    Purpose In addition to genomic signaling, it is accepted that ERα has non-nuclear signaling functions, which correlate with tamoxifen resistance in preclinical models. However, evidence for cytoplasmic ER localization in human breast tumors is less established. We sought to determine the presence and implications of non-nuclear ER in clinical specimens. Experimental Design A panel of ERα-specific antibodies (SP1, MC20, F10, 60c, 1D5) were validated by western blot and quantitative immunofluorescent (QIF) analysis of cell lines and patient controls. Then eight retrospective cohorts collected on tissue microarrays were assessed for cytoplasmic ER. Four cohorts were from Yale (YTMA 49, 107, 130, 128) and four others (NCI YTMA 99, South Swedish Breast Cancer Group SBII, NSABP B14, and a Vietnamese Cohort) from other sites around the world. Results Four of the antibodies specifically recognized ER by western and QIF, showed linear increases in amounts of ER in cell line series with progressively increasing ER, and the antibodies were reproducible on YTMA 49 with pearson’s correlations (r2 values)ranging from 0.87-0.94. One antibody with striking cytoplasmic staining (MC20) failed validation. We found evidence for specific cytoplasmic staining with the other 4 antibodies across eight cohorts. The average incidence was 1.5%, ranging from 0 to 3.2%. Conclusions Our data shows ERα present in the cytoplasm in a number of cases using multiple antibodies, while reinforcing the importance of antibody validation. In nearly 3,200 cases, cytoplasmic ER is present at very low incidence, suggesting its measurement is unlikely to be of routine clinical value. PMID:21980134

  20. Consequences of cytoplasmic irradiation. Studies from microbeam

    International Nuclear Information System (INIS)

    Zhou, Hongning; Hong, Mei; Chai, Yunfei; Hei, Tom K.

    2009-01-01

    The prevailing dogma for radiation biology is that genotoxic effects of ionizing radiation such as mutations and carcinogenesis are attributed mainly to direct damage to the nucleus. However, with the development of microbeam that can target precise positions inside the cells, accumulating evidences have shown that energy deposit by radiation in nuclear DNA is not required to trigger the damage, extra-nuclear or extra-cellular radiation could induce the similar biological effects as well. This review will summarize the biological responses after cytoplasm irradiated by microbeam, and the possible mechanisms involved in cytoplasmic irradiation. (author)

  1. 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

  2. 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

  3. Fisetin Induces Apoptosis of HSC3 Human Oral Cancer Cells Through Endoplasmic Reticulum Stress and Dysfunction of Mitochondria-mediated Signaling Pathways.

    Science.gov (United States)

    Shih, Yung-Luen; Hung, Fang-Ming; Lee, Ching-Hsiao; Yeh, Ming-Yang; Lee, Mei-Hui; Lu, Hsu-Feng; Chen, Yung-Liang; Liu, Jia-You; Chung, Jing-Gung

    2017-01-01

    Oral cancer has been reported to be one of the major cancer-related diseases in human populations and the treatment of oral cancer is still unsatisfied. Fisetin, is a flavonoid from plants and has several biological activities such as antioxidant, anti-inflammatory and anticancer function, but its cytotoxicity in human oral cancer cells is unknown. In the present study, we investigated fisetin-induced cytotoxic effects on HSC3 human oral cancer cells in vitro. Materials and Methods/Results: We used flow cytometric assay to show fisetin induced apoptotic cell death through increased reactive oxygen species and Ca 2+ , but reduced the mitochondrial membrane potential and increased caspase-8, -9 and -3 activities in HSC3 cells. Furthermore, we also used 4' 6-diamidino-2-phenylindole staining to show that fisetin induced chromatin condensation (apoptotic cell death), and Comet assay to show that fisetin induced DNA damage in HSC3 cells. Western blotting was used to examine the levels of apoptotic-associated protein and results indicated that fisetin increased expression of pro-apoptotic proteins such as B-cell lymphoma 2 (BCL2) antagonist/killer (BAK) and BCL2-associated X (BAX) but reduced that of anti-apoptotic protein such as BCL2 and BCL-x, and increased the cleaved forms of caspase-3, -8 and -9, and cytochrome c, apoptosis-inducing factor (AIF) and endonuclease G (ENDO G) in HSC3 cells. Confocal microscopy showed that fisetin increased the release of cytochrome c, AIF and ENDO G from mitochondria into the cytoplasm. Based on these observations, we suggest that fisetin induces apoptotic cell death through endoplasmic reticulum stress- and mitochondria-dependent pathways. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  4. Detection of antineutrophil cytoplasmic antibodies (ANCAs)

    DEFF Research Database (Denmark)

    Damoiseaux, Jan; Csernok, Elena; Rasmussen, Niels

    2017-01-01

    of diagnosis) from 251 patients with ANCA-associated vasculitis (AAV), including granulomatosis with polyangiitis and microscopic polyangiitis, and from 924 disease controls were tested for the presence of cytoplasmic pattern/perinuclear pattern and atypical ANCA (A-ANCA) by indirect immunofluorescence (IIF...

  5. How crowded is the prokaryotic cytoplasm?

    NARCIS (Netherlands)

    Spitzer, Jan; Poolman, Bert; Ferguson, Stuart

    2013-01-01

    We consider biomacromolecular crowding within the cytoplasm of prokaryotic cells as a two-phase system of 'supercrowded' cytogel and 'dilute' cytosol; we simplify and quantify this model for a coccoid cell over a wide range of biomacromolecular crowding. The key result shows that the supercrowded

  6. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Curious Sex Ratios and Cytoplasmic Genes Microbes Can Distort the Sex Ratio of Populations. Stephen J Freeland Laurence D Hurst. General Article Volume 2 Issue 6 June 1997 pp 68-78 ...

  7. 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),

  8. Ultrastructural changes in aster yellows phytoplasma affected Limonium sinuatum Mill. plants II. Pathology of cortex parenchyma cells

    Directory of Open Access Journals (Sweden)

    Anna Rudzińska-Langwald

    2014-01-01

    Full Text Available In Limonium sinuatum Mill, plants with severe symptoms of aster yellows infection phytoplasmas were present not only in the phloem but also in some cortex parenchymas cells. These parenchyma cells were situated at some distance from the conducting bundles. The phytoplasmas were observed directly in parenchyma cells cytoplasm. The number of phytoplasmas present in each selected cell varies. The cells with a small number of phytoplasmas show little pathological changes compared with the unaffected cells of the same zone of the stem as well with the cells of healthy plants. The cells filled with a number of phytoplasmas had their protoplast very much changed. The vacuole was reduced and in the cytoplasm a reduction of the number of ribosomes was noted and regions of homogenous structure appeared. Mitochondria were moved in the direction of the tonoplast and plasma membrane. Compared to the cells unaffected by phytoplasma, the mitochondria were smaller and had an enlarged cristae internal space. The chloroplasts from affected cells had a very significant reduction in size and the tylacoids system had disappeared. The role of these changes for creating phytoplasma friendly enviroment is discused.

  9. Production of ABA responses requires both the nuclear and cytoplasmic functional involvement of PYR1

    International Nuclear Information System (INIS)

    Park, EunJoo; Kim, Tae-Houn

    2017-01-01

    Abscisic acid (ABA) enhances stress tolerant responses in plants against unfavorable environmental conditions. In Arabidopsis, ABA promotes interactions between PYR/PYL/RCARs and PP2C, thereby allowing SnRK2s to phosphorylate downstream components required for the regulation of gene expression or for gating ion channels. Because PYR1 is known to localize to nucleus and cytoplasm it is a question whether nuclear or cytoplasmic PYR1 confer different functions to the ABA signaling pathway, as has been previously shown for regulatory proteins. In order to answer this question, transgenic lines expressing nuclear PYR1 were generated in an ABA insensitive mutant background. Enforced nuclear expression of PYR1 was examined by confocal microscopy and western blot analysis. Physiological analyses of the transgenic lines demonstrated that nuclear PYR1 is sufficient to generate ABA responses, such as, the inhibition of seed germination, root growth inhibition, the induction of gene expression, and stomatal closing movement. However, for the full recovery of ABA responses in the mutant background cytoplasmic PYR1 was required. The study suggests both nuclear and cytoplasmic PYR1 participate in the control of ABA signal transduction. - Highlights: • Nuclear and cytoplasmic functions of PYR1 were studied in the mutant which lacked majority of ABA responses. • Nuclear PYR1 reconstituted partially the ABA responses during seed germination, root growth, and guard cell movement. • Both the nuclear and cytoplasmic functions of PYR1 were required for the full generation of ABA responses.

  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. 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

  12. 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.

  13. Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Takahashi

    Full Text Available A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells.

  14. 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.

  15. 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.

  16. The effect of 2,4-D and ABA on respiration of isolated mitochondria from maize coleoptiles

    Directory of Open Access Journals (Sweden)

    Ewa Raczek

    2014-01-01

    Full Text Available The susceptibility of isolated maize mitochondria to the growth regulators: 2,4-dichlorophenoxyacetic acid (2,4-D and abscisic acid (ABA was studied. It was found that 2,4-D (a herbicide inhibits respiration in mitochondria, as do other herbicides or phenoxy-acids. In the entire range of concentrations used (10-3-10-9 M, 2,4-D introduced into the medium before the respiration reaction was begun, or during it, limited the intensity of succinate oxidation. It did not, however, markedly change phosphorylation properties. Uncoupling of oxidative phosphorylation took place only after preincubation of mitochondria with 2,4-D and was the result of the destruction of mitochondrial membranes. ABA (a growth inhibitor of plants caused a similar response in maize mitochondria. Preincubation of mitochondria with ABA lead to the uncoupling of oxidative phosphorylation. Whereas ABA introduced during respiration (state 4 respiration or before its onset, lowered the oxidative potential of mitochondria, it also changed the pattern of state 4-3-4 transition after addition of ADP (it was especially visible at high concentrations, which indicates that the coupling of oxidative phosphorylation with the respiratory chain has faltered. It seems that this negative effect of 2,4-D and ABA on respiration of isolated maize mitochondria is connected with the inhibitory effect of these growth regulators on the growth of maize coleoptiles. Interference in the organization mitochondrial membranes results in a lowered supply of ATP - a source of energy needed in elongation processes.

  17. 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

  18. Non-coding RNA may be associated with cytoplasmic male sterility in Silene vulgaris

    Czech Academy of Sciences Publication Activity Database

    Stone, James D.; Koloušková, Pavla; Sloan, D.B.; Štorchová, Helena

    2017-01-01

    Roč. 68, č. 7 (2017), s. 1599-1612 ISSN 0022-0957 R&D Projects: GA ČR(CZ) GA16-09220S Institutional support: RVO:61389030 Keywords : Cytoplasmic male sterility * Editing * Mitochondrion * Non-coding RNA * Silene vulgaris * Splicing * Transcriptome Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

  19. 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...

  20. Xenopus egg cytoplasm with intact actin.

    Science.gov (United States)

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts. © 2014 Elsevier Inc. All rights reserved.

  1. Cytoplasmic lipid bodies of human neutrophilic leukocytes

    International Nuclear Information System (INIS)

    Weller, P.F.; Ackerman, S.J.; Nicholson-Weller, A.; Dvorak, A.M.

    1989-01-01

    The morphology and function of cytoplasmic lipid bodies in human neutrophils were evaluated. By transmission electron microscopy, neutrophil lipid bodies were cytoplasmic inclusions, usually several microns in diameter, that occasionally coalesced to attain a diameter up to 7 microM. Neutrophil lipid bodies were not enveloped by membrane but were often surrounded by a more electron-dense shell at their periphery. Normal peripheral blood neutrophils contained an average of approximately one lipid body per cell. Lipid bodies appeared in greater numbers in neutrophils from inflammatory lesions. Perturbation of neutrophils during conventional methods of cell isolation and purification modestly increased lipid body numbers in neutrophils, whereas incubation of neutrophils with 1 microM oleic acid rapidly induced lipid body formation over 30 to 60 minutes. After granulocytes were incubated for 2 hours with 3H-fatty acids, including arachidonic, oleic, and palmitic acids, electron microscopic autoradiography demonstrated that lipid bodies represented the predominant intracellular sites of localization of each of the three 3H-fatty acids. There was lesser labeling noted in the perinuclear cisterna, but not in cell membranes. Virtually all of each of the three 3H-fatty acids incorporated by the neutrophils were esterified into chromatographically resolved classes of neutral lipids or phospholipids. These findings indicate that cytoplasmic lipid bodies are more prominent in neutrophils in vivo engaged in inflammatory responses and that these organelles in human neutrophils function as sites of deposition of esterified, incorporated fatty acids

  2. Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation.

    Directory of Open Access Journals (Sweden)

    Eugénie Ansseau

    Full Text Available Hundreds of double homeobox (DUX genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD. In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain and DUX1 (which is limited to the double homeodomain. Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs. Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs

  3. Discovery of global genomic re-organization based on comparison of two newly sequenced rice mitochondrial genomes with cytoplasmic male sterility-related genes

    Directory of Open Access Journals (Sweden)

    Yamada Mari

    2010-03-01

    Full Text Available Abstract Background Plant mitochondrial genomes are known for their complexity, and there is abundant evidence demonstrating that this organelle is important for plant sexual reproduction. Cytoplasmic male sterility (CMS is a phenomenon caused by incompatibility between the nucleus and mitochondria that has been discovered in various plant species. As the exact sequence of steps leading to CMS has not yet been revealed, efforts should be made to elucidate the factors underlying the mechanism of this important trait for crop breeding. Results Two CMS mitochondrial genomes, LD-CMS, derived from Oryza sativa L. ssp. indica (434,735 bp, and CW-CMS, derived from Oryza rufipogon Griff. (559,045 bp, were newly sequenced in this study. Compared to the previously sequenced Nipponbare (Oryza sativa L. ssp. japonica mitochondrial genome, the presence of 54 out of 56 protein-encoding genes (including pseudo-genes, 22 tRNA genes (including pseudo-tRNAs, and three rRNA genes was conserved. Two other genes were not present in the CW-CMS mitochondrial genome, and one of them was present as part of the newly identified chimeric ORF, CW-orf307. At least 12 genomic recombination events were predicted between the LD-CMS mitochondrial genome and Nipponbare, and 15 between the CW-CMS genome and Nipponbare, and novel genetic structures were formed by these genomic rearrangements in the two CMS lines. At least one of the genomic rearrangements was completely unique to each CMS line and not present in 69 rice cultivars or 9 accessions of O. rufipogon. Conclusion Our results demonstrate novel mitochondrial genomic rearrangements that are unique in CMS cytoplasm, and one of the genes that is unique in the CW mitochondrial genome, CW-orf307, appeared to be the candidate most likely responsible for the CW-CMS event. Genomic rearrangements were dynamic in the CMS lines in comparison with those of rice cultivars, suggesting that 'death' and possible 'birth' processes of the

  4. Antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitis

    NARCIS (Netherlands)

    Kallenberg, Cees G. M.

    Purpose of reviews This review focuses on recent advance in the diagnosis pathogenesis and treatment of antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitis. Recent findings Antineutrophil cytoplasmic autoantibodies are closely associated with Wegener's granulomatosis and

  5. 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...

  6. 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.

  7. 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.

  8. Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells.

    Directory of Open Access Journals (Sweden)

    Sae Tanaka

    Full Text Available Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble and SAHS (Secretory Abundant Heat Soluble proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble, as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments.

  9. 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.

  10. 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

  11. 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.

  12. 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....

  13. Optical tweezers for the micromanipulation of plant cytoplasm and organelles

    NARCIS (Netherlands)

    Hawes, C.; Osterrieder, A.; Sparkes, I.A.; Ketelaar, T.

    2010-01-01

    Laser tweezers, often known as optical tweezers or optical traps, permit the capturing and micromanipulation of microscopic particles along X, Y and Z axes using the radiation pressure generated by a focused laser beam, normally in the infrared region of the spectrum. For trapping to be successful,

  14. Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment.

    Science.gov (United States)

    Xia, J. H.; Roberts, JKM.

    1996-05-01

    We tested the hypothesis that H+ extrusion contributes to cytoplasmic pH regulation and tolerance of anoxia in maize (Zea mays) root tips. We studied root tips of whole seedlings that were acclimated to a low-oxygen environment by pretreatment in 3% (v/v) O2. Acclimated root tips characteristically regulate cytoplasmic pH near neutrality and survive prolonged anoxia, whereas nonacclimated tips undergo severe cytoplasmic acidosis and die much more quickly. We show that the plasma membrane H+-ATPase can operate under anoxia and that net H+ extrusion increases when cytoplasmic pH falls. However, at an external pH near 6.0, H+ extrusion contributes little to cytoplasmic pH regulation. At more acidic external pH values, net H+ flux into root tips increases dramatically, leading to a decrease in cytoplasmic pH and reduced tolerance of anoxia. We present evidence that, under these conditions, H+ pumps are activated to partly offset acidosis due to H+ influx and, thereby, contribute to cytoplasmic pH regulation and tolerance of anoxia. The regulation of H+ extrusion under anoxia is discussed with respect to the acclimation response and mechanisms of intracellular pH regulation in aerobic plant cells.

  15. An improved, simple, inexpensive and highly flexible hydroponic setup for root mitochondria isolation from arabidopsis and nicotiana pants

    International Nuclear Information System (INIS)

    Hameed, M. W.; Udddin, A.

    2015-01-01

    Hydroponic setups are frequently developed and improved as they are convenient platforms for studying whole plant physiology. Mostly, the available systems produce small amounts of plant material and are therefore, unsuitable for studies requiring large quantities of plant material like isolation of mitochondria. To address this issue, we have modified a hydroponic setup that can sustain hundreds of Arabidopsis and tobacco plants until adult plants are established. The setup is very flexible and easy to construct. It is based on the use of recyclable and sterilizable plastic-net-pots and media containers, which are easily available from the local suppliers. The modified seed-pots and styrofoam sheets facilitate the transfer and harvesting of seedlings. We have used the Percoll based two-step density gradient centrifugation method for the isolation of root mitochondria from the hydroponically grown plants. (author)

  16. 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.

  17. 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.

  18. Structure and function of initiator methionine tRNA from the mitochondria of Neurospora crassa

    International Nuclear Information System (INIS)

    Heckman, J.E.; Hecker, L.I.; Schwartzbach, S.D.; Barnett, W.E.; Baumstark, B.; RajBhandary, U.L.

    1978-01-01

    Initiator methionine tRNA from the mitochondria of Neurospora crassa has been purified and sequenced. This mitochondrial tRNA can be aminoacylated and formylated by E. coli enzymes, and is capable of initiating protein synthesis in E. coli extracts. The nucleotide composition of the mitochondrial initiator tRNA (the first mitochondrial tRNA subjected to sequence analysis) is very rich in A + U, like that reported for total mitochondrial tRNA. In two of the unique features which differentiate procaryotic from eucaryotic cytoplasmic initiator tRNAs, the mitochondrial tRNA appears to resemble the eucaryotic initiator tRNAs. Thus unlike procaryotic initiator tRNAs in which the 5' terminal nucleotide cannot form a Watson-Crick base pair to the fifth nucleotide from 3' end, the mitochondrial tRNA can form such a base pair; and like the eucaryotic cytoplasmic initiator tRNAs, the mitochondrial initiator tRNA lacks the sequence - T psiCG(or A) in loop IV. The corresponding sequence in the mitochondrial tRNA, however, is -UGCA- and not -AU(or psi)CG- as found in all eucaryotic cytoplasmic initiator tRNAs. In spite of some similarity of the mitochondrial initiator tRNA to both eucaryotic and procaryotic initiator tRNAs, the mitochondrial initiator tRNA is basically different from both these tRNAs. Between these two classes of initiator tRNAs, however, it is more homologous in sequence to procaryotic (56 to 60%) than to eucaryotic cytoplasmic initiator tRNAs

  19. 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.

  20. 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.

  1. Wild Nicotiana Species as a Source of Cytoplasmic Male Sterility in Nicotianatabacum

    Directory of Open Access Journals (Sweden)

    Nikova V

    2014-12-01

    Full Text Available The results of our experiments executed to obtain tobacco male sterile lines through interspecific hybridization are summarized. Ten wild species from the genus Nicotiana: N. excelsior (exc, N. amplexicaulis (amp, N. rustica (rus, Nicotianaglauca (gla, N. velutina (vel, N. benthamiana (ben, N. maritima (mar, N. paniculata (pan, N. longiflora (lon and N. africana (afr were used as cytoplasmic donors and N. tabacum, cv. HarmanliiskaBasma (HB as a donor of the nucleus. Genetic effects of cytoplasmic-nuclear interaction of the studied species are discussed. Our results suggested that cytoplasmic male sterility (CMS was expressed when the cytoplasms of the above mentioned wild Nicotiana species were combined with the nucleus of N. tabacum. The 10 sources of CMS obtained in tobacco were characterized by altered flower phenotypes. Flowers are classified into types according the stamen, pistil and corolla modification. All these CMS sources were backcrossed to Oriental tobaccos, cvs. Tekne, Nevrokop B-12, Kroumovgrad 90 and Djebel 576, to develop corresponding CMS lines. The investigated cytoplasms produced compete male sterility in all those cultivars. The CMS lines preserved flower types, specific for every “sterile” cytoplasm. The extent of male organ modifications varied from apparently normal (but pollenless stamens in CMS (pan, (afr, some plants of (vel (mar through different degrees of malformations (shriveled anther on shortened filaments (lon, pinnate-like anthers on filaments of normal length (amp, petal - (ben, pistil- or stigma-like structures (rus, (gla to lack of male reproductive organs in (exc and in some plants of (vel, (mar, (rus and (gla. Most of the above mentioned cytoplasms had normal female gametophyte and good seed productivity. Alterations of the pistils were observed in CMS (rus, (exc and (ben causing reduction of the seed set. Electrophoresis of seed proteins of the tobacco cultivars and their CMS lines also suggested that

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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)

  7. 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

  8. 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.

  9. 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.

  10. Analysis of cytoplasmic effects and fine-mapping of a genic male sterile line in rice.

    Directory of Open Access Journals (Sweden)

    Peng Qin

    Full Text Available Cytoplasm has substantial genetic effects on progeny and is important for yield improvement in rice breeding. Studies on the cytoplasmic effects of cytoplasmic male sterility (CMS show that most types of CMS have negative effects on yield-related traits and that these negative effects vary among CMS. Some types of genic male sterility (GMS, including photo-thermo sensitive male sterility (PTMS, have been widely used in rice breeding, but the cytoplasmic effects of GMS remain unknown. Here, we identified a GMS mutant line, h2s, which exhibited small, white anthers and failed to produce mature pollen. Unlike CMS, the h2s had significant positive cytoplasmic effects on the seed set rate, weight per panicle, yield, and general combining ability (GCA for plant height, seed set rate, weight per panicle, and yield. These effects indicated that h2s cytoplasm may show promise for the improvement of rice yield. Genetic analysis suggested that the phenotype of h2s was controlled by a single recessive locus. We mapped h2s to a 152 kb region on chromosome 6, where 22 candidate genes were predicted. None of the 22 genes had previously been reported to be responsible for the phenotypes of h2s. Sequencing analysis showed a 12 bp deletion in the sixth exon of Loc_Os06g40550 in h2s in comparison to wild type, suggesting that Loc_Os06g40550 is the best candidate gene. These results lay a strong foundation for cloning of the H2S gene to elucidate the molecular mechanism of male reproduction.

  11. 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.

  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. Age-associated metabolic and morphologic changes in mitochondria of individual mouse and hamster oocytes.

    Directory of Open Access Journals (Sweden)

    Fatma Simsek-Duran

    Full Text Available BACKGROUND: In human oocytes, as in other mammalian ova, there is a significant variation in the pregnancy potential, with approximately 20% of oocyte-sperm meetings resulting in pregnancies. This frequency of successful fertilization decreases as the oocytes age. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. In this study, we have examined mitochondrial biogenesis in both hamster (Mesocricetus auratus and mouse (Mus musculus ova as models for understanding the effects of aging on mitochondrial structure and energy production within the mammalian oocyte. METHODOLOGY/PRINCIPAL FINDINGS: Individual metaphase II oocytes from a total of 25 young and old mice and hamsters were collected from ovarian follicles after hormone stimulation and prepared for biochemical or structural analysis. Adenosine triphosphate levels and mitochondrial DNA number were determined within individual oocytes from young and old animals. In aged hamsters, oocyte adenosine triphosphate levels and mitochondrial DNA molecules were reduced 35.4% and 51.8%, respectively. Reductions of 38.4% and 44% in adenosine triphosphate and mitochondrial genomes, respectively, were also seen in aged mouse oocytes. Transmission electron microscopic (TEM analysis showed that aged rodent oocytes had significant alterations in mitochondrial and cytoplasmic lamellae structure. CONCLUSIONS/SIGNIFICANCE: In both mice and hamsters, decreased adenosine triphosphate in aged oocytes is correlated with a similar decrease in mtDNA molecules and number of mitochondria. Mitochondria in mice and hamsters undergo significant morphological change with aging including mitochondrial vacuolization, cristae alterations, and changes in cytoplasmic lamellae.

  14. 2010 GORDON RESEARCH CONFERENCE ON MITOCHONDRIA & CHLOROPLASTS, LUCCA, ITALY, JULY 11-16, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Alice Barkan

    2010-07-16

    The 2010 GRC on Mitochondria & Chloroplasts will assemble an international group of molecular, structural and cellular biologists, biochemists and geneticists investigating a broad spectrum of fundamental problems related to the biology of these organelles in animal, plant and fungal cells. This field has witnessed an extraordinary expansion in recent years, fueled by the discovery of the role of mitochondria in human disease and ageing, and of the synergy of chloroplasts and mitochondria in energetic output, the identification of novel factors involved in organelle division, movement, signaling and acclimation to changing environmental conditions, and by the powerful tools of organelle proteomics. The 2010 GRC will highlight advances in the elucidation of molecular mechanisms of organelle biogenesis including regulation of genome structure, evolution and expression, organellar protein import, assembly and turnover of respiratory and photosynthetic complexes, bidirectional signaling between organelles and nucleus, organelle morphology and dynamics, and the integration of cellular metabolism. We will also explore progress in mechanisms of disease and ageing/ senescence in animals and plants. The organellar field has forged new fronts toward a global and comprehensive understanding of mitochondrial and chloroplast biology at the molecular level. Many of the molecules under study in model organisms are responsible for human diseases, providing significant impetus for a meeting that encourages interactions between mammalian, fungal and plant organellar biologists.

  15. Sequencing and annotation of the chloroplast DNAs and identification of polymorphisms distinguishing normal male-fertile and male-sterile cytoplasms of onion.

    Science.gov (United States)

    von Kohn, Christopher; Kiełkowska, Agnieszka; Havey, Michael J

    2013-12-01

    Male-sterile (S) cytoplasm of onion is an alien cytoplasm introgressed into onion in antiquity and is widely used for hybrid seed production. Owing to the biennial generation time of onion, classical crossing takes at least 4 years to classify cytoplasms as S or normal (N) male-fertile. Molecular markers in the organellar DNAs that distinguish N and S cytoplasms are useful to reduce the time required to classify onion cytoplasms. In this research, we completed next-generation sequencing of the chloroplast DNAs of N- and S-cytoplasmic onions; we assembled and annotated the genomes in addition to identifying polymorphisms that distinguish these cytoplasms. The sizes (153 538 and 153 355 base pairs) and GC contents (36.8%) were very similar for the chloroplast DNAs of N and S cytoplasms, respectively, as expected given their close phylogenetic relationship. The size difference was primarily due to small indels in intergenic regions and a deletion in the accD gene of N-cytoplasmic onion. The structures of the onion chloroplast DNAs were similar to those of most land plants with large and small single copy regions separated by inverted repeats. Twenty-eight single nucleotide polymorphisms, two polymorphic restriction-enzyme sites, and one indel distributed across 20 chloroplast genes in the large and small single copy regions were selected and validated using diverse onion populations previously classified as N or S cytoplasmic using restriction fragment length polymorphisms. Although cytoplasmic male sterility is likely associated with the mitochondrial DNA, maternal transmission of the mitochondrial and chloroplast DNAs allows for polymorphisms in either genome to be useful for classifying onion cytoplasms to aid the development of hybrid onion cultivars.

  16. An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems.

    Science.gov (United States)

    Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

    2016-01-01

    A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming. (1) Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming.

  17. Comparison of Gene Expression Profiles in Human Germinal Vesicle Before and After Cytoplasmic Transfer From Mature Oocytes in Iranian Infertile Couples

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    Fatemeh Sadat Hoseini

    2016-08-01

    Full Text Available Objective: To evaluate the effect of cytoplasm transfer from mature oocytes to germinal vesicle(GVs on promoting the maturation of cytoplasm of GV at the mRNA level.Materials and methods: Sixty six in vitro fertilization (IVF operations between June 2012 and November 2013 were included in this study. Totally 120 GVs were obtained. Normal GVs were categorized into 3 groups (n = 40 randomly: the first comprised oocytes that did not receive the cytoplasm of mature oocytes; the second group comprised oocytes that did not receive the cytoplasm of mature oocytes but were incubated for 24 h; and the third group comprised oocytes that received 10-15% the cytoplasm of mature oocytes and were then incubated for 24 h. Each group was separately analyzed by quantitative polymerase chain reaction (qPCR and the expression levels of selected genes were assessed.Results: The expression levels of genes involved in the cytoplasmic maturity, and energy-producing mitochondria were significantly higher in the pooled oocytes of 2nd control group than those of the 1st control and intervention groups (p < 0.001. The genes involved in the meiosis, spindle check point, DNA repairing and cell cycle checkpoint did not have any expression in the 1st and intervention groups; however, these genes were expressed in the 2nd group, significantly. In the 2nd group, the highest expression level was observed for genes involved in the DNA repairing and cell cycle checkpoint. In the intervention group, none of the genes were expressed except for energy-producing mitochondria gene; even in this case, the expression level of this gene in this group of oocytes was significantly lower than that in other groups (p < 0.001. After 24 h meiosis assumption was significantly higher in the third group than in the second group (95% vs. 68%, p < 0.001.Conclusion: The cytoplasm transfer technique is not effective in cytoplasmic maturity of the recipient GV oocytes. In contrast, 24-hr in

  18. Impaired succinic dehydrogenase activity of rat Purkinje cell mitochondria during aging.

    Science.gov (United States)

    Fattoretti, P; Bertoni-Freddari, C; Caselli, U; Paoloni, R; Meier-Ruge, W

    1998-03-16

    The perikaryal Purkinje cell mitochondria positive to the copper ferrocyanide histochemical reaction for succinic dehydrogenase (SDH) have been investigated by means of semiautomatic morphometric methods in rats of 3, 12 and 24 months of age. The number of organelles/microm3 of Purkinje cell cytoplasm (Numeric density: Nv), the average mitochondrial volume (V) and the mitochondrial volume fraction (Volume density: Vv) were the ultrastructural parameters taken into account. Nv was significantly higher at 12 than at 3 and 24 months of age. V was significantly decreased at 12 and 24 months of age, but no difference was envisaged between adult and old rats. Vv was significantly decreased in old animals vs. the other age groups. In young and old rats, the percentage of organelles larger than 0.32 microm3 was 13.5 and 11%, respectively, while these enlarged mitochondria accounted for less than 1% in the adult group. Since SDH activity is of critical importance when energy demand is high, the marked decrease of Vv supports an impaired capacity of the old Purkinje cells to match actual energy supply at sustained transmission of the nervous impulse. However, the high percentage of enlarged organelles found in old rats may witness a morphofunctional compensatory response.

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

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    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.

  20. Cytoplasmic male sterility contributes to hybrid incompatibility between subspecies of Arabidopsis lyrata.

    Science.gov (United States)

    Aalto, Esa A; Koelewijn, Hans-Peter; Savolainen, Outi

    2013-10-03

    In crosses between evolutionarily diverged populations, genomic incompatibilities may result in sterile hybrids, indicating evolution of reproductive isolation. In several plant families, crosses within a population can also lead to male sterile progeny because of conflict between the maternally and biparentally inherited genomes. We examined hybrid fertility between subspecies of the perennial outcrossing self-incompatible Lyrate rockcress (Arabidopsis lyrata) in large reciprocal F2 progenies and three generations of backcrosses. In one of the reciprocal F2 progenies, almost one-fourth of the plants were male-sterile. Correspondingly, almost one-half of the plants in one of the four reciprocal backcross progenies expressed male sterility. In an additional four independent F2 and backcross families, three segregated male sterility. The observed asymmetrical hybrid incompatibility is attributable to male sterility factors in one cytoplasm, for which the other population lacks effective fertility restorers. Genotyping of 96 molecular markers and quantitative trait locus mapping revealed that only 60% of the plants having the male sterile cytoplasm and lacking the corresponding restorers were phenotypically male-sterile. Genotyping data showed that there is only one restorer locus, which mapped to a 600-kb interval at the top of chromosome 2 in a region containing a cluster of pentatricopeptide repeat genes. Male fertility showed no trade-off with seed production. We discuss the role of cytoplasm and genomic conflict in incipient speciation and conclude that cytoplasmic male sterility-lowering hybrid fitness is a transient effect with limited potential to form permanent reproductive barriers between diverged populations of hermaphrodite self-incompatible species.

  1. 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

  2. Immunocytochemical analysis of the subcellular distribution of ferritin in Imperata cylindrica (L.) Raeuschel, an iron hyperaccumulator plant.

    Science.gov (United States)

    de la Fuente, Vicenta; Rodríguez, Nuria; Amils, Ricardo

    2012-05-01

    Ferritin is of interest at the structural and functional level not only as storage for iron, a critical element, but also as a means to prevent cell damage produced by oxidative stress. The main objective of this work was to confirm by immunocytochemistry the presence and the subcellular distribution of the ferritin detected by Mösbauer spectroscopy in Imperata cylindrica, a plant which accumulates large amounts of iron. The localization of ferritin was performed in epidermal, parenchymal and vascular tissues of shoots and leaves of I. cylindrica. The highest density of immunolabeling in shoots appeared in the intracellular space of cell tissues, near the cell walls and in the cytoplasm. In leaves, ferritin was detected in the proximity of the dense network of the middle lamella of cell walls, following a similar path to that observed in shoots. Immunolabeling was also localized in chloroplasts. The abundance of immunogold labelling in mitochondria for I. cylindrica was rather low, probably because the study dealt with tissues from old plants. These results further expand the localization of ferritin in cell components other than chloroplasts and mitochondria in plants. Copyright © 2011 Elsevier GmbH. All rights reserved.

  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. Regulation of autophagy by cytoplasmic p53.

    Science.gov (United States)

    Tasdemir, Ezgi; Maiuri, M Chiara; Galluzzi, Lorenzo; Vitale, Ilio; Djavaheri-Mergny, Mojgan; D'Amelio, Marcello; Criollo, Alfredo; Morselli, Eugenia; Zhu, Changlian; Harper, Francis; Nannmark, Ulf; Samara, Chrysanthi; Pinton, Paolo; Vicencio, José Miguel; Carnuccio, Rosa; Moll, Ute M; Madeo, Frank; Paterlini-Brechot, Patrizia; Rizzuto, Rosario; Szabadkai, Gyorgy; Pierron, Gérard; Blomgren, Klas; Tavernarakis, Nektarios; Codogno, Patrice; Cecconi, Francesco; Kroemer, Guido

    2008-06-01

    Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53(-/-) cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.

  7. Cytoplasmic Dynein Promotes HIV-1 Uncoating

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    Paulina Pawlica

    2014-11-01

    Full Text Available Retroviral capsid (CA cores undergo uncoating during their retrograde transport (toward the nucleus, and/or after reaching the nuclear membrane. However, whether HIV-1 CA core uncoating is dependent upon its transport is not understood. There is some evidence that HIV-1 cores retrograde transport involves cytoplasmic dynein complexes translocating on microtubules. Here we investigate the role of dynein-dependent transport in HIV-1 uncoating. To interfere with dynein function, we depleted dynein heavy chain (DHC using RNA interference, and we over-expressed p50/dynamitin. In immunofluorescence microscopy experiments, DHC depletion caused an accumulation of CA foci in HIV-1 infected cells. Using a biochemical assay to monitor HIV-1 CA core disassembly in infected cells, we observed an increase in amounts of intact (pelletable CA cores upon DHC depletion or p50 over-expression. Results from these two complementary assays suggest that inhibiting dynein-mediated transport interferes with HIV-1 uncoating in infected cells, indicating the existence of a functional link between HIV-1 transport and uncoating.

  8. Antineutrophil cytoplasm antibody: positivity and clinical correlation.

    Science.gov (United States)

    Martínez Téllez, Goitybell; Torres Rives, Bárbara; Rangel Velázquez, Suchiquil; Sánchez Rodríguez, Vicky; Ramos Ríos, María Antonia; Fuentes Smith, Lisset Evelyn

    2015-01-01

    To determine positivity and clinical correlation of anti-neutrophil cytoplasmic antibodies (ANCA), taking into account the interference of antinuclear antibodies (ANA). A prospective study was conducted in the Laboratory of Immunology of the National Cuban Center of Medical Genetic during one year. Two hounded sixty-seven patients with indication for ANCA determination were included. ANCA and ANA determinations with different cut off points and assays were determined by indirect immunofluorescense. Anti proteinase 3 and antimyeloperoxidase antibodies were determined by ELISA. Most positivity for ANCA was seen in patients with ANCA associated, primary small-vessel vasculitides, rheumatoid arthritis and systemic lupus erythematosus. Presence of ANCA without positivity for proteinase 3 and myeloperoxidase was higher in patients with ANA and little relation was observed between the perinuclear pattern confirmed in formalin and specificity by myeloperoxidase. Highest sensibility and specificity values for vasculitides diagnostic were achieved by ANCA determination using indirect immunofluorescense with a cut off 1/80 and confirming antigenic specificities with ELISA. ANCA can be present in a great number of chronic inflammatory or autoimmune disorders in the population studied. This determination using indirect immunofluorescence and following by ELISA had a great value for vasculitis diagnosis. Anti mieloperoxidasa assay has a higher utility than the formalin assay when ANA is present. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

  9. 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

  10. NDV-induced apoptosis in absence of Bax; evidence of involvement of apoptotic proteins upstream of mitochondria

    Directory of Open Access Journals (Sweden)

    Molouki Aidin

    2012-08-01

    Full Text Available Abstract Background Recently it was shown that following infection of HeLa cells with Newcastle disease virus (NDV, the matrix (M protein binds to Bax and subsequently the intrinsic pathway of apoptosis is activated. Moreover, there was very little alteration on mRNA and protein levels of Bax and Bcl-2 after infection with NDV. Finding In order to further investigate the role of members of the Bcl-2 family, Bax-knockout and wild-type HCT116 cells were infected with NDV strain AF2240. Although both cells underwent apoptosis through the activation of the intrinsic pathway and the release of cytochrome c from mitochondria, the percentage of dead Bax-knockout cells was significantly lower than wt cells (more than 10% at 48 h post-infection. In a parallel experiment, the effect of NDV on HT29 cells, that are originally Bcl-2-free, was studied. Apoptosis in HT29 cells was associated with Bax redistribution from cytoplasm to mitochondria, similar to that of HeLa and wt HCT116 cells. Conclusion Although the presence of Bax during NDV-induced apoptosis contributes to a faster cell death, it was concluded that other apoptotic protein(s upstream of mitochondria are also involved since cancer cells die whether in the presence or absence of Bax. Therefore, the classic Bax/Bcl-2 ratio may not be a major determinant in NDV-induced apoptosis.

  11. 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

  12. Mitochondria: Target organelles for estrogen action

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    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.

  13. Molecular studies of functional aspects of plant mitochondria. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Siedow, J.N.

    1992-03-03

    The goal of this research is to characterize the mechanism by which a protein encoded by mitochondrial genome of cms-T maize (URF13) interacts with a family of the compounds produced by certain fungi (T-toxins) to permeabilize biological membranes. The research carried out during the current funding period has focused on the structure of URF13, and the results support the validity of the three-helix model of URF13 and provide direct evidence for the oligomeric nature of at least some of the URF13 molecules in the membrane. In addition, the toxin binding studies have provided insight into the dynamic nature of the T-toxin:URF13 interaction and the extent to which Asp-39 is crucial to the interaction that leads to membrane pore formation. Additional knowledge of the structure of URF13 is needed if the nature of the interaction between URF13 and T-toxin to produce a hydrophilic pore within the membrane is to ultimately be understood.

  14. Molecular studies of functional aspects of plant mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Siedow, J.N.

    1992-03-03

    The goal of this research is to characterize the mechanism by which a protein encoded by mitochondrial genome of cms-T maize (URF13) interacts with a family of the compounds produced by certain fungi (T-toxins) to permeabilize biological membranes. The research carried out during the current funding period has focused on the structure of URF13, and the results support the validity of the three-helix model of URF13 and provide direct evidence for the oligomeric nature of at least some of the URF13 molecules in the membrane. In addition, the toxin binding studies have provided insight into the dynamic nature of the T-toxin:URF13 interaction and the extent to which Asp-39 is crucial to the interaction that leads to membrane pore formation. Additional knowledge of the structure of URF13 is needed if the nature of the interaction between URF13 and T-toxin to produce a hydrophilic pore within the membrane is to ultimately be understood.

  15. Berberine as a promising safe anti-cancer agent - is there a role for mitochondria?

    Science.gov (United States)

    Diogo, Catia V; Machado, Nuno G; Barbosa, Inês A; Serafim, Teresa L; Burgeiro, Ana; Oliveira, Paulo J

    2011-06-01

    Metabolic regulation is largely dependent on mitochondria, which play an important role in energy homeostasis. Imbalance between energy intake and expenditure leads to mitochondrial dysfunction, characterized by a reduced ratio of energy production (ATP production) to respiration. Due to the role of mitochondrial factors/events in several apoptotic pathways, the possibility of targeting that organelle in the tumor cell, leading to its elimination is very attractive, although the safety issue is problematic. Berberine, a benzyl-tetra isoquinoline alkaloid extracted from plants of the Berberidaceae family, has been extensively used for many centuries, especially in the traditional Chinese and Native American medicine. Several evidences suggest that berberine possesses several therapeutic uses, including anti-tumoral activity. The present review supplies evidence that berberine is a safe anti-cancer agent, exerting several effects on mitochondria, including inhibition of mitochondrial Complex I and interaction with the adenine nucleotide translocator which can explain several of the described effects on tumor cells.

  16. Construction of a bacterial artificial chromosome library of S-type CMS maize mitochondria

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to isolate mitochondrial genes easily, we have developed a new method to construct S-type CMS maize mitochondrial gene library by means of embedding mitochondria and enzymatic digesting mitochondria in situ, preparing mtDNA by electrophoresis, digesting LMP agarose with β-agarase, using BAC vector and electroporation. About 2 500 white clones of Mo17 CMS-J mitochondrial gene library were obtained with the average size of 18.24 kb, ranging from 5 to 40 kb, 63.6% inserts came from mitochondrial genome and represented 48 ′ mitochondrial genome equivalents. All the probes had detected the positive clones in the gene library. It is helpful to elucidating the maize mitochondrial genome structure and mechanism of S-type CMS, and may give some valuable reference to the construction of other plant mitochondrial genome library.

  17. Antineutrophil Cytoplasmic Antibodies, Autoimmune Neutropenia, and Vasculitis

    Science.gov (United States)

    Grayson, Peter C.; Sloan, J. Mark; Niles, John L.; Monach, Paul A.; Merkel, Peter A.

    2011-01-01

    Objectives Reports of an association between antineutrophil cytoplasmic antibodies (ANCA) and autoimmune neutropenia have rarely included cases of proven vasculitis. A case of ANCA-associated vasculitis (AAV) with recurrent neutropenia is described and relevant literature on the association between ANCA, neutropenia, and vasculitis is reviewed. Methods Longitudinal clinical assessments and laboratory findings are described in a patient with AAV and recurrent episodes of profound neutropenia from December 2008 – October 2010. A PubMed database search of the medical literature was performed for papers published from 1960 through October 2010 to identify all reported cases of ANCA and neutropenia. Results A 49 year-old man developed recurrent neutropenia, periodic fevers, arthritis, biopsy-proven cutaneous vasculitis, sensorineural hearing loss, epididymitis, and positive tests for ANCA with specificity for antibodies to both proteinase 3 and myeloperoxidase. Antineutrophil membrane antibodies were detected during an acute neutropenic phase and were not detectable in a post-recovery sample, whereas ANCA titers did not seem to correlate with neutropenia. An association between ANCA and neutropenia has been reported in 74 cases from 24 studies in the context of drug/toxin exposure, underlying autoimmune disease, or chronic neutropenia without underlying autoimmune disease. In these cases, the presence of atypical ANCA patterns and other antibodies were common; however, vasculitis was uncommon and when it occurred was usually limited to the skin and in cases of underlying toxin exposure. Conclusions ANCA is associated with autoimmune neutropenia, but systemic vasculitis rarely occurs in association with ANCA and neutropenia. The interaction between neutrophils and ANCA may provide insight into understanding both autoimmune neutropenia and AAV. PMID:21507463

  18. Antineutrophil Cytoplasmic Antibodies Associated With Infective Endocarditis

    Science.gov (United States)

    Langlois, Vincent; Lesourd, Anais; Girszyn, Nicolas; Ménard, Jean-Francois; Levesque, Hervé; Caron, Francois; Marie, Isabelle

    2016-01-01

    Abstract To determine the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in patients with infective endocarditis (IE) in internal medicine; and to compare clinical and biochemical features and outcome between patients exhibiting IE with and without ANCA. Fifty consecutive patients with IE underwent ANCA testing. The medical records of these patients were reviewed. Of the 50 patients with IE, 12 exhibited ANCA (24%). ANCA-positive patients with IE exhibited: longer duration between the onset of first symptoms and IE diagnosis (P = 0.02); and more frequently: weight loss (P = 0.017) and renal impairment (P = 0.08), lower levels of C-reactive protein (P = 0.0009) and serum albumin (P = 0.0032), involvement of both aortic and mitral valves (P = 0.009), and longer hospital stay (P = 0.016). Under multivariate analysis, significant factors for ANCA-associated IE were: longer hospital stay (P = 0.004), lower level of serum albumin (P = 0.02), and multiple valve involvement (P = 0.04). Mortality rate was 25% in ANCA patients; death was because of IE complications in all these patients. Our study identifies a high prevalence of ANCA in unselected patients with IE in internal medicine (24%). Our findings further underscore that ANCA may be associated with a subacute form of IE leading to multiple valve involvement and more frequent renal impairment. Because death was due to IE complications in all patients, our data suggest that aggressive therapy may be required to improve such patients’ outcome. PMID:26817911

  19. 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.

  20. 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

  1. 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

  2. Effect of drought stress on male fertility restoration in A3 CMS-inducing cytoplasm of sorghum

    Directory of Open Access Journals (Sweden)

    Valentin V. Kozhemyakin

    2017-08-01

    Full Text Available Use of cytoplasmic male sterility (CMS in hybrid breeding requires effective male fertility-restoring lines. In sorghum, very few restoring lines that can restore fertility in A3 CMS have been reported. To identify the reasons for this deficiency, F1 and F2 hybrids of an A3 CMS line crossed with the line IS1112C, a donor of fertility-restoring (Rf genes for A3 cytoplasm, and testcrosses of fertile plants to A3 CMS lines were grown under contrasting water availability regimes in dryland and irrigated field plots. In the irrigated plots the frequency of fertile plants in testcrosses was twice that in dryland plots (P < 0.05. Fertile plants from the F2 family grown in the irrigated plots showed significantly higher restoration ability than fertile plants from the same family grown in dryland plots. F3 plants from the F2 family grown in irrigated plots yielded on average a sixfold higher frequency of fertile plants in testcrosses than F3 plants derived from dryland plots (P < 0.01. Fertility of testcross hybrids correlated negatively with air vapor pressure deficit (VPD at flowering (r = −0.96; P < 0.01 suggesting that VPD is a trigger for downregulation of Rf genes for A3 cytoplasm.

  3. Coupled Ca2+/H+ transport by cytoplasmic buffers regulates local Ca2+ and H+ ion signaling.

    Science.gov (United States)

    Swietach, Pawel; Youm, Jae-Boum; Saegusa, Noriko; Leem, Chae-Hun; Spitzer, Kenneth W; Vaughan-Jones, Richard D

    2013-05-28

    Ca(2+) signaling regulates cell function. This is subject to modulation by H(+) ions that are universal end-products of metabolism. Due to slow diffusion and common buffers, changes in cytoplasmic [Ca(2+)] ([Ca(2+)]i) or [H(+)] ([H(+)]i) can become compartmentalized, leading potentially to complex spatial Ca(2+)/H(+) coupling. This was studied by fluorescence imaging of cardiac myocytes. An increase in [H(+)]i, produced by superfusion of acetate (salt of membrane-permeant weak acid), evoked a [Ca(2+)]i rise, independent of sarcolemmal Ca(2+) influx or release from mitochondria, sarcoplasmic reticulum, or acidic stores. Photolytic H(+) uncaging from 2-nitrobenzaldehyde also raised [Ca(2+)]i, and the yield was reduced following inhibition of glycolysis or mitochondrial respiration. H(+) uncaging into buffer mixtures in vitro demonstrated that Ca(2+) unloading from proteins, histidyl dipeptides (HDPs; e.g., carnosine), and ATP can underlie the H(+)-evoked [Ca(2+)]i rise. Raising [H(+)]i tonically at one end of a myocyte evoked a local [Ca(2+)]i rise in the acidic microdomain, which did not dissipate. The result is consistent with uphill Ca(2+) transport into the acidic zone via Ca(2+)/H(+) exchange on diffusible HDPs and ATP molecules, energized by the [H(+)]i gradient. Ca(2+) recruitment to a localized acid microdomain was greatly reduced during intracellular Mg(2+) overload or by ATP depletion, maneuvers that reduce the Ca(2+)-carrying capacity of HDPs. Cytoplasmic HDPs and ATP underlie spatial Ca(2+)/H(+) coupling in the cardiac myocyte by providing ion exchange and transport on common buffer sites. Given the abundance of cellular HDPs and ATP, spatial Ca(2+)/H(+) coupling is likely to be of general importance in cell signaling.

  4. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    International Nuclear Information System (INIS)

    Gou, Ke-Mian; Chang, Chia-Chun; Shen, Qing-Ji; Sung, Li-Ying; Liu, Ji-Long

    2014-01-01

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus

  5. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Gou, Ke-Mian [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193 (China); Chang, Chia-Chun [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Shen, Qing-Ji [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); Sung, Li-Ying, E-mail: liyingsung@ntu.edu.tw [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan, ROC (China); Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom)

    2014-04-15

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

  6. Pediatric Inflammatory Bowel Disease with Cytoplasmic Staining of Antineutrophil Cytoplasmic Antibodies

    Directory of Open Access Journals (Sweden)

    Omar I. Saadah

    2013-01-01

    Full Text Available Background. It is unusual for the antineutrophil cytoplasmic antibody with cytoplasmic pattern (cANCA to present in patients with inflammatory bowel disease (IBD without vasculitis. The purpose of this study was to describe the occurrence and characteristics of pediatrics IBD with cANCA. Methods. A retrospective review of pediatric IBD associated with cANCA serology in patients from King Abdulaziz University Hospital, Saudi Arabia, between September 2002 and February 2012. Results. Out of 131 patients with IBD screened for cANCAs, cANCA was positive in 7 (5.3% patients of whom 4 had ulcerative colitis and 3 had Crohn's disease. The median age was 8.8 years (2–14.8 years. Six (86% were males. Of the 7 patients, 5 (71% were Saudi Arabians and 2 were of Indian ethnicity. The most common symptoms were diarrhea, abdominal pain, weight loss, and rectal bleeding. None had family history or clinical features suggestive of vasculitis involving renal and respiratory systems. No difference in the disease location or severity was observed between cANCA positive and cANCA negative patients apart from male preponderance in cANCA positive patients. Conclusion. The occurrence of cANCA in pediatric IBD is rare. Apart from male preponderance, there were no peculiar characteristics for the cANCA positive patients.

  7. 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

  8. 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'.

  9. 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.

  10. 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.

  11. 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.

  12. Development of new semidwarf sources for rice with different cytoplasms (CV Basmati 370 and Gloria)

    Energy Technology Data Exchange (ETDEWEB)

    Deus, J E; Suarez, E [Instituto de Investigaciones del Arroz, Bauta, Havana (Cuba); Fuentes, J L; Alvarez, A; Padron, E [Centro de Estudios Aplicados al Desarrollo Nuclear, Miramar, Playa, Havana (Cuba)

    2001-05-01

    In Cuba semidwarf rice varieties grow on 98% of the area. Virtually all carry the same Dee-geo-won-gen dwarfing gene. Also, most if not all the cultivars have the same cytoplasm. The induced mutations approach was undertaken in order to generate alternative genetic sources of dwarfing with different cytoplasms and to improve the grain quality of Cuban rice. The seeds of two varieties, Basmati 370 and Gloria, were irradiated with 200 and 300 Gy of {sup 60}Co gamma rays. In several generations of selection, progeny testing and preliminary yield tests 10 mutants (6 from Basmati 370 and 4 from Gloria), whose yields exceeded the source cultivars, have been advanced to replicated yield trials. Some of the mutant lines are also resistant to lodging and to blast (Pyricularis grisea). It is concluded the induced mutations can be used successfully to improve plant type and other agronomic traits in rice. The induced mutants will be used also in hybridization programs. (author)

  13. Development of new semidwarf sources for rice with different cytoplasms (CV Basmati 370 and Gloria)

    International Nuclear Information System (INIS)

    Deus, J.E.; Suarez, E.; Fuentes, J.L.; Alvarez, A.; Padron, E.

    2001-01-01

    In Cuba semidwarf rice varieties grow on 98% of the area. Virtually all carry the same Dee-geo-won-gen dwarfing gene. Also, most if not all the cultivars have the same cytoplasm. The induced mutations approach was undertaken in order to generate alternative genetic sources of dwarfing with different cytoplasms and to improve the grain quality of Cuban rice. The seeds of two varieties, Basmati 370 and Gloria, were irradiated with 200 and 300 Gy of 60 Co gamma rays. In several generations of selection, progeny testing and preliminary yield tests 10 mutants (6 from Basmati 370 and 4 from Gloria), whose yields exceeded the source cultivars, have been advanced to replicated yield trials. Some of the mutant lines are also resistant to lodging and to blast (Pyricularis grisea). It is concluded the induced mutations can be used successfully to improve plant type and other agronomic traits in rice. The induced mutants will be used also in hybridization programs. (author)

  14. Cytomorphology and Cytochemical Localization of K-type and T-type Cytoplasmic Male Sterile Pollens in Wheat

    Institute of Scientific and Technical Information of China (English)

    YAO Ya-qin; ZHANG Gai-sheng; LIU Hong-wei; WANG Jun-wei

    2003-01-01

    By using the technology of microscopy,electron microscopy and enzyme cytochemical localization, comparison was made of the cytomorphology, ATPase and cytochrome oxidase activity in pollens during microspore formation and pollen development, for K-type cytoplasmic male sterile (CMS) lines, T-type CMS lines and their maintainer lines on wheat. The results indicated that pollen abortion of the T-type CMS lines mainly occurred at the later mononucleate pollen stage, and cytomorphological changes of the abortive pollen began with a vacuolar membrane, and pollen aborting was related to a lack of ATPase activity in the nucleus and nucleolus during the mononucleate pollen stage. Pollen abortion of the K-type CMS lines took place mainly during the later binucleate and trinucleate stages, and cytomorphological changes of the abortion first began with mitochondria. The abortion was related to intine disruption.

  15. Refractory disease in antineutrophil cytoplasmic antibodies associated vasculitis

    NARCIS (Netherlands)

    Rutgers, Abraham; Kallenberg, Cornelis

    Purpose of review Induction treatment of antineutrophil cytoplasmic antibodies (ANCA) associated vasculitis (AAV) is not always successful and nonresponding patients are considered refractory. Recent findings Refractory disease should be subdefined to the treatment that was received.

  16. Cytoplasmic ATR Activation Promotes Vaccinia Virus Genome Replication

    Directory of Open Access Journals (Sweden)

    Antonio Postigo

    2017-05-01

    Full Text Available In contrast to most DNA viruses, poxviruses replicate their genomes in the cytoplasm without host involvement. We find that vaccinia virus induces cytoplasmic activation of ATR early during infection, before genome uncoating, which is unexpected because ATR plays a fundamental nuclear role in maintaining host genome integrity. ATR, RPA, INTS7, and Chk1 are recruited to cytoplasmic DNA viral factories, suggesting canonical ATR pathway activation. Consistent with this, pharmacological and RNAi-mediated inhibition of canonical ATR signaling suppresses genome replication. RPA and the sliding clamp PCNA interact with the viral polymerase E9 and are required for DNA replication. Moreover, the ATR activator TOPBP1 promotes genome replication and associates with the viral replisome component H5. Our study suggests that, in contrast to long-held beliefs, vaccinia recruits conserved components of the eukaryote DNA replication and repair machinery to amplify its genome in the host cytoplasm.

  17. Evaluation of cytoplasmic genetic effects for production and ...

    African Journals Online (AJOL)

    uvp

    2014-12-03

    Dec 3, 2014 ... Cytoplasmic genetic effects are transmitted directly only from mother to offspring through mitochondrial DNA. Normal genetic .... inheritance in three synthetic lines of beef cattle differing in mature size. J. Anim. Sci. 69, 745.

  18. Vasculitis and antineutrophil cytoplasmic autoantibodies associated with propylthiouracil therapy

    NARCIS (Netherlands)

    Dolman, K. M.; Gans, R. O.; Vervaat, T. J.; Zevenbergen, G.; Maingay, D.; Nikkels, R. E.; Donker, A. J.; von dem Borne, A. E.; Goldschmeding, R.

    1993-01-01

    Vasculitis is a rare complication of propylthiouracil therapy. Antineutrophil cytoplasmic antibodies (ANCA) have been described in association with several vasculitic disorders. We report detection of ANCA against human neutrophil elastase, proteinase 3, and myeloperoxidase in serum from six

  19. Transcriptome analysis of cytoplasmic male sterility and restoration in CMS-D8 cotton.

    Science.gov (United States)

    Suzuki, Hideaki; Rodriguez-Uribe, Laura; Xu, Jiannong; Zhang, Jinfa

    2013-10-01

    A global view of differential expression of genes in CMS-D8 of cotton was presented in this study which will facilitate the understanding of cytoplasmic male sterility in cotton. Cytoplasmic male sterility (CMS) is a maternally inherited trait in higher plants which is incapable of producing functional pollen. However, the male fertility can be restored by one or more nuclear-encoded restorer genes. A genome-wide transcriptome analysis of CMS and restoration in cotton is currently lacking. In this study, Affymetrix GeneChips© Cotton Genome Array containing 24,132 transcripts was used to compare differentially expressed (DE) genes of flower buds at the meiosis stage between CMS and its restorer cotton plants conditioned by the D8 cytoplasm. A total of 458 (1.9 %) of DE genes including 127 up-regulated and 331 down-regulated ones were identified in the CMS-D8 line. Quantitative RT-PCR was used to validate 10 DE genes selected from seven functional categories. The most frequent DE gene group was found to encode putative proteins involved in cell wall expansion, such as pectinesterase, pectate lyase, pectin methylesterase, glyoxal oxidase, polygalacturonase, indole-3-acetic acid-amino synthetase, and xyloglucan endo-transglycosylase. Genes in cytoskeleton category including actin, which plays a key role in cell wall expansion, cell elongation and cell division, were also highly differentially expressed between the fertile and CMS plants. This work represents the first study in utilizing microarray to identify CMS-related genes by comparing overall DE genes between fertile and CMS plants in cotton. The results provide evidence that many CMS-associated genes are mainly involved in cell wall expansion. Further analysis will be required to elucidate the molecular mechanisms of male sterility which will facilitate the development of new hybrid cultivars in cotton.

  20. Bovine lactoferricin causes apoptosis in Jurkat T-leukemia cells by sequential permeabilization of the cell membrane and targeting of mitochondria

    International Nuclear Information System (INIS)

    Mader, Jamie S.; Richardson, Angela; Salsman, Jayme; Top, Deniz; Antueno, Roberto de; Duncan, Roy; Hoskin, David W.

    2007-01-01

    Bovine lactoferricin (LfcinB) is a cationic antimicrobial peptide that kills Jurkat T-leukemia cells by the mitochondrial pathway of apoptosis. However, the process by which LfcinB triggers mitochondria-dependent apoptosis is not well understood. Here, we show that LfcinB-induced apoptosis in Jurkat T-leukemia cells was preceded by LfcinB binding to, and progressive permeabilization of the cell membrane. Colloidal gold electron microscopy revealed that LfcinB entered the cytoplasm of Jurkat T-leukemia cells prior to the onset of mitochondrial depolarization. LfcinB was not internalized by endocytosis because endocytosis inhibitors did not prevent LfcinB-induced cytotoxicity. Furthermore, intracellular delivery of LfcinB via fusogenic liposomes caused the death of Jurkat T-leukemia cells, as well as normal human fibroblasts. Collectively, these findings suggest that LfcinB caused damage to the cell membrane that allowed LfcinB to enter the cytoplasm of Jurkat T-leukemia cells and mediate cytotoxicity. In addition, confocal microscopy showed that intracellular LfcinB co-localized with mitochondria in Jurkat T-leukemia cells, while flow cytometry and colloidal gold electron microscopy showed that LfcinB rapidly associated with purified mitochondria. Furthermore, purified mitochondria treated with LfcinB rapidly lost transmembrane potential and released cytochrome c. We conclude that LfcinB-induced apoptosis in Jurkat T-leukemia cells resulted from cell membrane damage and the subsequent disruption of mitochondrial membranes by internalized LfcinB

  1. Activity and functional interaction of alternative oxidase and uncoupling protein in mitochondria from tomato fruit

    Directory of Open Access Journals (Sweden)

    F.E. Sluse

    2000-03-01

    Full Text Available Cyanide-resistant alternative oxidase (AOX is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP is much more widespread than previously believed, not only in tissues of higher animals but also in plants and in an amoeboid protozoan. The redox energy-dissipating pathway (AOX and the proton electrochemical gradient energy-dissipating pathway (UCP lead to the same final effect, i.e., a decrease in ATP synthesis and an increase in heat production. Studies with green tomato fruit mitochondria show that both proteins are present simultaneously in the membrane. This raises the question of a specific physiological role for each energy-dissipating system and of a possible functional connection between them (shared regulation. Linoleic acid, an abundant free fatty acid in plants which activates UCP, strongly inhibits cyanide-resistant respiration mediated by AOX. Moreover, studies of the evolution of AOX and UCP protein expression and of their activities during post-harvest ripening of tomato fruit show that AOX and plant UCP work sequentially: AOX activity decreases in early post-growing stages and UCP activity is decreased in late ripening stages. Electron partitioning between the alternative oxidase and the cytochrome pathway as well as H+ gradient partitioning between ATP synthase and UCP can be evaluated by the ADP/O method. This method facilitates description of the kinetics of energy-dissipating pathways and of ATP synthase when state 3 respiration is decreased by limitation of oxidizable substrate.

  2. The different fates of mitochondria and chloroplasts during dark-induced senescence in Arabidopsis leaves.

    Science.gov (United States)

    Keech, Olivier; Pesquet, Edouard; Ahad, Abdul; Askne, Anna; Nordvall, Dag; Vodnala, Sharvani Munender; Tuominen, Hannele; Hurry, Vaughan; Dizengremel, Pierre; Gardeström, Per

    2007-12-01

    Senescence is an active process allowing the reallocation of valuable nutrients from the senescing organ towards storage and/or growing tissues. Using Arabidopsis thaliana leaves from both whole darkened plants (DPs) and individually darkened leaves (IDLs), we investigated the fate of mitochondria and chloroplasts during dark-induced leaf senescence. Combining in vivo visualization of fates of the two organelles by three-dimensional reconstructions of abaxial parts of leaves with functional measurements of photosynthesis and respiration, we showed that the two experimental systems displayed major differences during 6 d of dark treatment. In whole DPs, organelles were largely retained in both epidermal and mesophyll cells. However, while the photosynthetic capacity was maintained, the capacity of mitochondrial respiration decreased. In contrast, IDLs showed a rapid decline in photosynthetic capacity while maintaining a high capacity for mitochondrial respiration throughout the treatment. In addition, we noticed an unequal degradation of organelles in the different cell types of the senescing leaf. From these data, we suggest that metabolism in leaves of the whole DPs enters a 'stand-by mode' to preserve the photosynthetic machinery for as long as possible. However, in IDLs, mitochondria actively provide energy and carbon skeletons for the degradation of cell constituents, facilitating the retrieval of nutrients. Finally, the heterogeneity of the degradation processes involved during senescence is discussed with regard to the fate of mitochondria and chloroplasts in the different cell types.

  3. Cytoplasmic chromatin triggers inflammation in senescence and cancer.

    Science.gov (United States)

    Dou, Zhixun; Ghosh, Kanad; Vizioli, Maria Grazia; Zhu, Jiajun; Sen, Payel; Wangensteen, Kirk J; Simithy, Johayra; Lan, Yemin; Lin, Yanping; Zhou, Zhuo; Capell, Brian C; Xu, Caiyue; Xu, Mingang; Kieckhaefer, Julia E; Jiang, Tianying; Shoshkes-Carmel, Michal; Tanim, K M Ahasan Al; Barber, Glen N; Seykora, John T; Millar, Sarah E; Kaestner, Klaus H; Garcia, Benjamin A; Adams, Peter D; Berger, Shelley L

    2017-10-19

    Chromatin is traditionally viewed as a nuclear entity that regulates gene expression and silencing. However, we recently discovered the presence of cytoplasmic chromatin fragments that pinch off from intact nuclei of primary cells during senescence, a form of terminal cell-cycle arrest associated with pro-inflammatory responses. The functional significance of chromatin in the cytoplasm is unclear. Here we show that cytoplasmic chromatin activates the innate immunity cytosolic DNA-sensing cGAS-STING (cyclic GMP-AMP synthase linked to stimulator of interferon genes) pathway, leading both to short-term inflammation to restrain activated oncogenes and to chronic inflammation that associates with tissue destruction and cancer. The cytoplasmic chromatin-cGAS-STING pathway promotes the senescence-associated secretory phenotype in primary human cells and in mice. Mice deficient in STING show impaired immuno-surveillance of oncogenic RAS and reduced tissue inflammation upon ionizing radiation. Furthermore, this pathway is activated in cancer cells, and correlates with pro-inflammatory gene expression in human cancers. Overall, our findings indicate that genomic DNA serves as a reservoir to initiate a pro-inflammatory pathway in the cytoplasm in senescence and cancer. Targeting the cytoplasmic chromatin-mediated pathway may hold promise in treating inflammation-related disorders.

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

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    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.

  5. 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.

  6. 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....

  7. 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.

  8. GABA transaminases from Saccharomyces cerevisiae and Arabidopsis thaliana complement function in cytosol and mitochondria.

    Science.gov (United States)

    Cao, Juxiang; Barbosa, Jose M; Singh, Narendra; Locy, Robert D

    2013-07-01

    GABA transaminase (GABA-T) catalyses the conversion of GABA to succinate semialdehyde (SSA) in the GABA shunt pathway. The GABA-T from Saccharomyces cerevisiae (ScGABA-TKG) is an α-ketoglutarate-dependent enzyme encoded by the UGA1 gene, while higher plant GABA-T is a pyruvate/glyoxylate-dependent enzyme encoded by POP2 in Arabidopsis thaliana (AtGABA-T). The GABA-T from A. thaliana is localized in mitochondria and mediated by an 18-amino acid N-terminal mitochondrial targeting peptide predicated by both web-based utilities TargetP 1.1 and PSORT. Yeast UGA1 appears to lack a mitochondrial targeting peptide and is localized in the cytosol. To verify this bioinformatic analysis and examine the significance of ScGABA-TKG and AtGABA-T compartmentation and substrate specificity on physiological function, expression vectors were constructed to modify both ScGABA-TKG and AtGABA-T, so that they express in yeast mitochondria and cytosol. Physiological function was evaluated by complementing yeast ScGABA-TKG deletion mutant Δuga1 with AtGABA-T or ScGABA-TKG targeted to the cytosol or mitochondria for the phenotypes of GABA growth defect, thermosensitivity and heat-induced production of reactive oxygen species (ROS). This study demonstrates that AtGABA-T is functionally interchangeable with ScGABA-TKG for GABA growth, thermotolerance and limiting production of ROS, regardless of location in mitochondria or cytosol of yeast cells, but AtGABA-T is about half as efficient in doing so as ScGABA-TKG. These results are consistent with the hypothesis that pyruvate/glyoxylate-limited production of NADPH mediates the effect of the GABA shunt in moderating heat stress in Saccharomyces. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Cytoplasmic vacuolation in cultured rat astrocytes induced by an organophosphorus agent requires extracellular signal-regulated kinase activation

    International Nuclear Information System (INIS)

    Isobe, Ichiro; Maeno, Yoshitaka; Nagao, Masataka; Iwasa, Mineo; Koyama, Hiroyoshi; Seko-Nakamura, Yoshimi; Monma-Ohtaki, Jun

    2003-01-01

    There are various toxic chemicals that cause cell death. However, in certain cases deleterious agents elicit various cellular responses prior to cell death. To determine the cellular mechanisms by which such cellular responses are induced is important, but sufficient attention has not been paid to this issue to date. In this study, we showed the characteristic effects of an organophosphorus (OP) agent, bis(pinacolyl methyl)phosphonate (BPMP), which we synthesized for the study of OP nerve agents, on cultured rat astrocytes. Morphologically, BPMP induced cytoplasmic vacuolation and stellation in the rat astrocytes. Cytoplasmic vacuolation is a cell pathological change observed, for example, in vacuolar degeneration, and stellation has been reported in astrocytic reactions against various stimuli. By pretreatment with cycloheximide, a protein synthesis inhibitor, stellation was inhibited, although vacuolation was not. Cell staining with a mitochondrion-selective dye indicated that the vacuolation probably occurs in the mitochondria that are swollen and vacuolatred in the center. Interestingly, the extracellular signal-regulated kinase (ERK) cascade inhibitor inhibited vacuolation and, to some extent, stellation. These results suggest that the ERK signaling cascade is important for the induction of mitochondrial vacuolation. We expect that a detailed study of these astrocytic reactions will provide us new perspectives regarding the variation and pathological significance of cell morphological changes, such as vacuolar degeneration, and also the mechanisms underlying various neurological disorders

  10. Protein synthesis and the recovery of both survival and cytoplasmic ''petite'' mutation in ultraviolet-treated yeast cells

    International Nuclear Information System (INIS)

    Heude, M.; Chanet, R.

    1975-01-01

    The contribution of mitochondrial proteins in the repair of UV-induced lethal and cytoplasmic genetic damages was studied in dark liquid-held exponential and stationary phase yeast cells. This was performed by using the specific inhibitors, erythromycin and chloramphenicol. It was shown that mitochondrial proteins are involved in the recovery and survival of UV-treated exponential phase cells, but not in the recovery of stationary phase cells. Mitochondrial proteins are partly implicated in the mechanisms leading to the restoration of the e + genotype in UV-irradiated dark liquid-held exponential phase cells. Here again, in stationary phase cells, mitochondrial enzymes do not seem to participate in the negative liquid-holding process for the e - induction, as shown by inhibiting mitochondrial protein synthesis of both mitochondrial and nuclear protein synthesis. When cells are grown in glycerol, the response after dark liquid-holding of the UV-treated cells in the different growth stages are similar to that found for glucose-grown cells. In other words, the fate of cytoplasmic genetic damage in particular is not correlated with the repressed or derepressed state of the mitochondria

  11. Development of Novel Cytoplasmic Male Sterile Source from Dongxiang Wild Rice (Oryza rufipogon

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    Xian-hua SHEN

    2013-09-01

    Full Text Available This study was conducted to develop and characterize a novel cytoplasmic male sterile (CMS source which was identified from Dongxiang wild rice (Oryza rufipogon by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm (CMS-WA. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm (CMS-HL and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.

  12. The DEAD box helicase RDE-12 promotes amplification of RNAi in cytoplasmic foci in C. elegans.

    Science.gov (United States)

    Yang, Huan; Vallandingham, Jim; Shiu, Philip; Li, Hua; Hunter, Craig P; Mak, Ho Yi

    2014-04-14

    RNAi is a potent mechanism for downregulating gene expression. Conserved RNAi pathway components are found in animals, plants, fungi, and other eukaryotes. In C. elegans, the RNAi response is greatly amplified by the synthesis of abundant secondary small interfering RNAs (siRNAs). Exogenous double-stranded RNA is processed by Dicer and RDE-1/Argonaute into primary siRNA that guides target mRNA recognition. The RDE-10/RDE-11 complex and the RNA-dependent RNA polymerase RRF-1 then engage the target mRNA for secondary siRNA synthesis. However, the molecular link between primary siRNA production and secondary siRNA synthesis remains largely unknown. Furthermore, it is unclear whether the subcellular sites for target mRNA recognition and degradation coincide with sites where siRNA synthesis and amplification occur. In the C. elegans germline, cytoplasmic P granules at the nuclear pores and perinuclear Mutator foci contribute to target mRNA surveillance and siRNA amplification, respectively. We report that RDE-12, a conserved phenylalanine-glycine (FG) domain-containing DEAD box helicase, localizes in P granules and cytoplasmic foci that are enriched in RSD-6 but are excluded from the Mutator foci. Our results suggest that RDE-12 promotes secondary siRNA synthesis by orchestrating the recruitment of RDE-10 and RRF-1 to primary siRNA-targeted mRNA in distinct cytoplasmic compartments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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...

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

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    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. Nucleocapsid Protein from Fig Mosaic Virus Forms Cytoplasmic Agglomerates That Are Hauled by Endoplasmic Reticulum Streaming

    Science.gov (United States)

    Ishikawa, Kazuya; Miura, Chihiro; Maejima, Kensaku; Komatsu, Ken; Hashimoto, Masayoshi; Tomomitsu, Tatsuya; Fukuoka, Misato; Yusa, Akira; Yamaji, Yasuyuki

    2014-01-01

    throughout the cell, and we performed live imaging and ultrastructural analysis to identify the mechanism of motility. We provide evidence that cytoplasmic protein agglomerates were passively dragged by actomyosin-mediated streaming of the endoplasmic reticulum (ER) in plant cells. In virus-infected cells, NP agglomerates were surrounded by the ER membranes, indicating that NP agglomerates form the basis of enveloped virus particles in close proximity to the ER. Our work provides a sophisticated model of macromolecular trafficking in plant cells and improves our understanding of the formation of enveloped particles of negative-strand RNA viruses. PMID:25320328

  2. Disruption of reducing pathways is not essential for efficient disulfide bond formation in the cytoplasm of E. coli

    Directory of Open Access Journals (Sweden)

    Hatahet Feras

    2010-09-01

    Full Text Available Abstract Background The formation of native disulfide bonds is a complex and essential post-translational modification for many proteins. The large scale production of these proteins can be difficult and depends on targeting the protein to a compartment in which disulfide bond formation naturally occurs, usually the endoplasmic reticulum of eukaryotes or the periplasm of prokaryotes. It is currently thought to be impossible to produce large amounts of disulfide bond containing protein in the cytoplasm of wild-type bacteria such as E. coli due to the presence of multiple pathways for their reduction. Results Here we show that the introduction of Erv1p, a sulfhydryl oxidase and FAD-dependent catalyst of disulfide bond formation found in the inter membrane space of mitochondria, allows the efficient formation of native disulfide bonds in heterologously expressed proteins in the cytoplasm of E. coli even without the disruption of genes involved in disulfide bond reduction, for example trxB and/or gor. Indeed yields of active disulfide bonded proteins were higher in BL21 (DE3 pLysSRARE, an E. coli strain with the reducing pathways intact, than in the commercial Δgor ΔtrxB strain rosetta-gami upon co-expression of Erv1p. Conclusions Our results refute the current paradigm in the field that disruption of at least one of the reducing pathways is essential for the efficient production of disulfide bond containing proteins in the cytoplasm of E. coli and open up new possibilities for the use of E. coli as a microbial cell factory.

  3. Diverse accumulation of several dehydrin-like proteins in cauliflower (Brassica oleracea var. botrytis), Arabidopsis thaliana and yellow lupin (Lupinus luteus) mitochondria under cold and heat stress.

    Science.gov (United States)

    Rurek, Michal

    2010-08-18

    Dehydrins represent hydrophilic proteins acting mainly during cell dehydration and stress response. Dehydrins are generally thermostable; however, the so-called dehydrin-like (dehydrin-related) proteins show variable thermolability. Both groups immunoreact with antibodies directed against the K-segment of dehydrins. Plant mitochondrial dehydrin-like proteins are poorly characterized. The purpose of this study was to extend previous reports on plant dehydrins by comparing the level of immunoprecipitated dehydrin-like proteins in cauliflower (Brassica oleracea var. botrytis), Arabidopsis thaliana and yellow lupin (Lupinus luteus) mitochondria under cold and heat stress. All the analyzed plant species showed constitutive accumulation of thermostable mitochondrial putative dehydrins ranging from 50 to 70 kDa. The mitochondrial dehydrin-like proteins observed in cauliflower and Arabidopsis ranged from 10 to 100 kDa and in lupin imbibed seeds and hypocotyls--from 20 to 90 kDa. Cold treatment increased mainly the accumulation of 10-100 kDa cauliflower and Arabidopsis dehydrin-like proteins, in the patterns different in cauliflower leaf and inflorescence mitochondria. However, in lupin mitochondria, cold affected mainly 25-50 kDa proteins and seemed to induce the appearance of some novel dehydrin-like proteins. The influence of frost stress on cauliflower leaf mitochondrial dehydrin- like proteins was less significant. The impact of heat stress was less significant in lupin and Arabidopsis than in cauliflower inflorescence mitochondria. Cauliflower mitochondrial dehydrin-like proteins are localized mostly in the mitochondrial matrix; it seems that some of them may interact with mitochondrial membranes. All the results reveal an unexpectedly broad spectrum of dehydrin-like proteins accumulated during some abiotic stress in the mitochondria of the plant species analyzed. They display only limited similarity in size to those reported previously in maize, wheat and rye

  4. Ca2+ transport in plant cells and mechanisms of transformation of phytochrome-induced photosignals

    Science.gov (United States)

    Volotovski, Igor D.

    1995-01-01

    The recent data on the influence of phytochrome on the efficiency of Ca2+ translocation across the membranes of oat protoplasts are given. Ca2+ uptake in the protoplasts was shown to be influenced by the red light (R) illumination. This effect was reverted by the following far-red light (FR) illumination. To elucidate the sensitivity to phytochrome-controlling action the screening between the mechanisms of Ca2+ transport across the plasma membranes of oat protoplasts, Na+/Ca2+ and Ca2+/H+ exchangers, Ca2+-pump and Ca2+-channel was done. It was established that phytochrome modulated the activity of Na+/Ca2+-exchanger and Ca2+-pump. The light-mediated oscillations of cytoplasmic Ca2+ concentration in the oat protoplasts were demonstrated using fluorescence probe quin2 loaded into the cells and laser monitoring of fluorescence signal. The evidences were obtained that the oscillations were not the result of the elevation of cytoplasmic Ca2+ concentration and had no connection with Ca2+ pool of mitochondria. The possibility of the relation between the Ca2+ oscillations and phosphoinositide metabolism in plant cell membranes is analyzed. The mechanisms of transformation of primary phytochrome signal into biological effects were discussed.

  5. Lack of FTSH4 Protease Affects Protein Carbonylation, Mitochondrial Morphology, and Phospholipid Content in Mitochondria of Arabidopsis: New Insights into a Complex Interplay.

    Science.gov (United States)

    Smakowska, Elwira; Skibior-Blaszczyk, Renata; Czarna, Malgorzata; Kolodziejczak, Marta; Kwasniak-Owczarek, Malgorzata; Parys, Katarzyna; Funk, Christiane; Janska, Hanna

    2016-08-01

    FTSH4 is one of the inner membrane-embedded ATP-dependent metalloproteases in mitochondria of Arabidopsis (Arabidopsis thaliana). In mutants impaired to express FTSH4, carbonylated proteins accumulated and leaf morphology was altered when grown under a short-day photoperiod, at 22°C, and a long-day photoperiod, at 30°C. To provide better insight into the function of FTSH4, we compared the mitochondrial proteomes and oxyproteomes of two ftsh4 mutants and wild-type plants grown under conditions inducing the phenotypic alterations. Numerous proteins from various submitochondrial compartments were observed to be carbonylated in the ftsh4 mutants, indicating a widespread oxidative stress. One of the reasons for the accumulation of carbonylated proteins in ftsh4 was the limited ATP-dependent proteolytic capacity of ftsh4 mitochondria, arising from insufficient ATP amount, probably as a result of an impaired oxidative phosphorylation (OXPHOS), especially complex V. In ftsh4, we further observed giant, spherical mitochondria coexisting among normal ones. Both effects, the increased number of abnormal mitochondria and the decreased stability/activity of the OXPHOS complexes, were probably caused by the lower amount of the mitochondrial membrane phospholipid cardiolipin. We postulate that the reduced cardiolipin content in ftsh4 mitochondria leads to perturbations within the OXPHOS complexes, generating more reactive oxygen species and less ATP, and to the deregulation of mitochondrial dynamics, causing in consequence the accumulation of oxidative damage. © 2016 American Society of Plant Biologists. All Rights Reserved.

  6. 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.

  7. Cytoplasmic Flow Enhances Organelle Dispersion in Eukaryotic Cells

    Science.gov (United States)

    Koslover, Elena; Mogre, Saurabh; Chan, Caleb; Theriot, Julie

    The cytoplasm of a living cell is an active environment through which intracellular components move and mix. We explore, using theoretical modeling coupled with microrheological measurements, the efficiency of particle dispersion via different modes of transport within this active environment. In particular, we focus on the role of cytoplasmic flow over different scales in contributing to organelle transport within two different cell types. In motile neutrophil cells, we show that bulk fluid flow associated with rapid cell deformation enhances particle transport to and from the cell periphery. In narrow fungal hyphae, localized flows due to hydrodynamic entrainment are shown to contribute to optimally efficient organelle dispersion. Our results highlight the importance of non-traditional modes of transport associated with flow of the cytoplasmic fluid in the distribution of organelles throughout eukaryotic cells.

  8. Organelle Simple Sequence Repeat Markers Help to Distinguish Carpelloid Stamen and Normal Cytoplasmic Male Sterile Sources in Broccoli

    Science.gov (United States)

    Shu, Jinshuai; Liu, Yumei; Li, Zhansheng; Zhang, Lili; Fang, Zhiyuan; Yang, Limei; Zhuang, Mu; Zhang, Yangyong; Lv, Honghao

    2015-01-01

    We previously discovered carpelloid stamens when breeding cytoplasmic male sterile lines in broccoli (Brassica oleracea var. italica). In this study, hybrids and multiple backcrosses were produced from different cytoplasmic male sterile carpelloid stamen sources and maintainer lines. Carpelloid stamens caused dysplasia of the flower structure and led to hooked or coiled siliques with poor seed setting, which were inherited in a maternal fashion. Using four distinct carpelloid stamens and twelve distinct normal stamens from cytoplasmic male sterile sources and one maintainer, we used 21 mitochondrial simple sequence repeat (mtSSR) primers and 32 chloroplast SSR primers to identify a mitochondrial marker, mtSSR2, that can differentiate between the cytoplasm of carpelloid and normal stamens. Thereafter, mtSSR2 was used to identify another 34 broccoli accessions, with an accuracy rate of 100%. Analysis of the polymorphic sequences revealed that the mtSSR2 open reading frame of carpelloid stamen sterile sources had a deletion of 51 bases (encoding 18 amino acids) compared with normal stamen materials. The open reading frame is located in the coding region of orf125 and orf108 of the mitochondrial genomes in Brassica crops and had the highest similarity with Raphanus sativus and Brassica carinata. The current study has not only identified a useful molecular marker to detect the cytoplasm of carpelloid stamens during broccoli breeding, but it also provides evidence that the mitochondrial genome is maternally inherited and provides a basis for studying the effect of the cytoplasm on flower organ development in plants. PMID:26407159

  9. Mitochondrial redox biology and homeostasis in plants.

    Science.gov (United States)

    Noctor, Graham; De Paepe, Rosine; Foyer, Christine H

    2007-03-01

    Mitochondria are key players in plant cell redox homeostasis and signalling. Earlier concepts that regarded mitochondria as secondary to chloroplasts as the powerhouses of photosynthetic cells, with roles in cell proliferation, death and ageing described largely by analogy to animal paradigms, have been replaced by the new philosophy of integrated cellular energy and redox metabolism involving mitochondria and chloroplasts. Thanks to oxygenic photosynthesis, plant mitochondria often operate in an oxygen- and carbohydrate-rich environment. This rather unique environment necessitates extensive flexibility in electron transport pathways and associated NAD(P)-linked enzymes. In this review, mitochondrial redox metabolism is discussed in relation to the integrated cellular energy and redox function that controls plant cell biology and fate.

  10. A novel mitochondrial orf147 causes cytoplasmic male sterility in pigeonpea by modulating aberrant anther dehiscence.

    Science.gov (United States)

    Bhatnagar-Mathur, Pooja; Gupta, Ranadheer; Reddy, Palakolanu Sudhakar; Reddy, Bommineni Pradeep; Reddy, Dumbala Srinivas; Sameerkumar, C V; Saxena, Rachit Kumar; Sharma, Kiran K

    2018-05-01

    A novel open reading frame (ORF) identified and cloned from the A4 cytoplasm of Cajanus cajanifolius induced partial to complete male sterility when introduced into Arabidopsis and tobacco. Pigeonpea (Cajanus cajan L. Millsp.) is the only legume known to have commercial hybrid seed technology based on cytoplasmic male sterility (CMS). We identified a novel ORF (orf147) from the A4 cytoplasm of C. cajanifolius that was created via rearrangements in the CMS line and co-transcribes with the known and unknown sequences. The bi/poly-cistronic transcripts cause gain-of-function variants in the mitochondrial genome of CMS pigeonpea lines having distinct processing mechanisms and transcription start sites. In presence of orf147, significant repression of Escherichia coli growth indicated its toxicity to the host cells and induced partial to complete male sterility in transgenic progenies of Arabidopsis thaliana and Nicotiana tabacum where phenotype co-segregated with the transgene. The male sterile plants showed aberrant floral development and reduced lignin content in the anthers. Gene expression studies in male sterile pigeonpea, Arabidopsis and tobacco plants confirmed down-regulation of several anther biogenesis genes and key genes involved in monolignol biosynthesis, indicative of regulation of retrograde signaling. Besides providing evidence for the involvement of orf147 in pigeonpea CMS, this study provides valuable insights into its function. Cytotoxicity and aberrant programmed cell death induced by orf147 could be important for mechanism underlying male sterility that offers opportunities for possible translation for these findings for exploiting hybrid vigor in other recalcitrant crops as well.

  11. 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.

  12. Bioimaging of Fluorescence-Labeled Mitochondria in Subcutaneously Grafted Murine Melanoma Cells by the “In Vivo Cryotechnique”

    Science.gov (United States)

    Lei, Ting; Huang, Zheng; Ohno, Nobuhiko; Wu, Bao; Sakoh, Takashi; Saitoh, Yurika; Saiki, Ikuo

    2014-01-01

    The microenvironments of organs with blood flow affect the metabolic profiles of cancer cells, which are influenced by mitochondrial functions. However, histopathological analyses of these aspects have been hampered by technical artifacts of conventional fixation and dehydration, including ischemia/anoxia. The purpose of this study was to combine the in vivo cryotechnique (IVCT) with fluorescent protein expression, and examine fluorescently labeled mitochondria in grafted melanoma tumors. The intensity of fluorescent proteins was maintained well in cultured B16-BL6 cells after cryotechniques followed by freeze-substitution (FS). In the subcutaneous tumors of mitochondria-targeted DsRed2 (mitoDsRed)-expressing cells, a higher number of cancer cells were found surrounding the widely opened blood vessels that contained numerous erythrocytes. Such blood vessels were immunostained positively for immunoglobulin M and ensheathed by basement membranes. MitoDsRed fluorescence was detected in scattering melanoma cells using the IVCT-FS method, and the total mitoDsRed volume in individual cancer cells was significantly decreased with the expression of markers of hypoxia. MitoDsRed was frequently distributed throughout the cytoplasm and in processes extending along basement membranes. IVCT combined with fluorescent protein expression is a useful tool to examine the behavior of fluorescently labeled cells and organelles. We propose that the mitochondrial volume is dynamically regulated in the hypoxic microenvironment and that mitochondrial distribution is modulated by cancer cell interactions with basement membranes. PMID:24394469

  13. The cytotoxic effect of oxybuprocaine on human corneal epithelial cells by inducing cell cycle arrest and mitochondria-dependent apoptosis.

    Science.gov (United States)

    Fan, W-Y; Wang, D-P; Wen, Q; Fan, T-J

    2017-08-01

    Oxybuprocaine (OBPC) is a widely used topical anesthetic in eye clinic, and prolonged and repeated usage of OBPC might be cytotoxic to the cornea, especially to the outmost corneal epithelium. In this study, we characterized the cytotoxic effect of OBPC on human corneal epithelial (HCEP) cells and investigated its possible cellular and molecular mechanisms using an in vitro model of non-transfected HCEP cells. Our results showed that OBPC at concentrations ranging from 0.025% to 0.4% had a dose- and time-dependent cytotoxicity to HCEP cells. Moreover, OBPC arrested the cells at S phase and induced apoptosis of these cells by inducing plasma membrane permeability, phosphatidylserine externalization, DNA fragmentation, and apoptotic body formation. Furthermore, OBPC could trigger the activation of caspase-2, -3, and -9, downregulate the expression of Bcl-xL, upregulate the expression of Bax along with the cytoplasmic amount of mitochondria-released apoptosis-inducing factor, and disrupt mitochondrial transmembrane potential. Our results suggest that OBPC has a dose- and time-dependent cytotoxicity to HCEP cells by inducing cell cycle arrest and cell apoptosis via a death receptor-mediated mitochondria-dependent proapoptotic pathway, and this novel finding provides new insights into the acute cytotoxicity and its toxic mechanisms of OBPC on HCEP cells.

  14. Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments

    International Nuclear Information System (INIS)

    Patheja, Pooja; Sahu, Khageswar

    2017-01-01

    Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MφCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MφCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation.

  15. Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments

    Energy Technology Data Exchange (ETDEWEB)

    Patheja, Pooja, E-mail: pooja.patheja8@gmail.com [Laser Biomedical Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh (India); Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra (India); Sahu, Khageswar [Laser Biomedical Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh (India)

    2017-06-15

    Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MφCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MφCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation.

  16. The antimicrobial peptides lactoferricin B and magainin 2 cross over the bacterial cytoplasmic membrane and reside in the cytoplasm.

    Science.gov (United States)

    Haukland, H H; Ulvatne, H; Sandvik, K; Vorland, L H

    2001-11-23

    The localization of immunolabelled antimicrobial peptides was studied using transmission electron microscopy. Staphylococcus aureus and Escherichia coli were exposed to lactoferricin B (17-41), lactoferricin B (17-31) and D-lactoferricin B (17-31). E. coli was also exposed to cecropin P1 and magainin 2. The lactoferricins were found in the cytoplasm of both bacteria. In S. aureus the amount of cytoplasmic lactoferricin B (17-41) was time- and concentration-dependent, reaching a maximum within 30 min. Cecropin P1 was confined to the cell wall, while magainin 2 was found in the cytoplasm of E. coli. The finding of intracellularly localized magainin is not reported previously.

  17. Role of mitochondria in radiation sensitivity

    International Nuclear Information System (INIS)

    Indo, Hiroko; Tomita, Kazuo; Majima, Hideyuki; Matsui, Hirofumi; Ozawa, Toshihiko

    2007-01-01

    This paper describes mainly the role of mitochondrial (Mt) manganese superoxide dismutase (MnSOD) for deciding the radiation sensitivity of cells. The fact that Mt concerns with apoptosis has been shown by the finding that change in Mt membrane potential relates with the cell death. Mt has the electron transport system to yield the cellular energy molecule (ATP) and from which electrons are leaked out in 2-3%, a considerably large proportion in a cell. The electrons react with oxygen nearby to yield SO (O 2 ·- ), which in turn induces apoptosis through oxidation stress (OS). On the other hand, MnSOD is transported in Mt from cytoplasm and excludes the reactive oxygen species (ROS) like SO. Studies by MnSOD gene-deletion, knockout, cDNA-transfection, and transgenesis have indicated MnSOD is essential for keeping life and resistance to OS. Authors have shown that overexpression of Mt MnSOD protects against radiation-induced cell death, suggesting that Mt participates in radiation sensitivity where SO is involved. Interestingly, MnSOD activity is low in cancer cells, its overexpression results in tumor suppression and MnSOD is a target in leukemia therapy. When MTS (Mt targeting sequence, necessary for the enzyme to enter Mt)-deleted MnSOD is transfected, cells lack resistance to radiation, indicating the enzyme must be present in Mt. Mt DNA damage leading to electron transport system impairment is found to increase ROS, and to be reversed by the transfection of MnSOD gene. Studies of Mt DNA damage in cancer cells where aerobic glycolysis is actively operated, are currently in progress lively, and are thought to promote the development of diagnosis and treatment of cancer. (R.T.)

  18. Cytoplasmic transduction peptide (CTP): New approach for the delivery of biomolecules into cytoplasm in vitro and in vivo

    International Nuclear Information System (INIS)

    Kim, Daeyou; Jeon, Choonju; Kim, Jeong-Hwan; Kim, Mi-Seon; Yoon, Cheol-Hee; Choi, In-Soo; Kim, Sung-Hoon; Bae, Yong-Soo

    2006-01-01

    The protein transduction domain (PTD) of HIV-1 TAT has been extensively documented with regard to its membrane transduction potential, as well as its efficient delivery of biomolecules in vivo. However, the majority of PTD and PTD-conjugated molecules translocate to the nucleus rather than to the cytoplasm after transduction, due to the functional nuclear localization sequence (NLS). Here, we report a cytoplasmic transduction peptide (CTP), which was deliberately designed to ensure the efficient cytoplasmic delivery of the CTP-fused biomolecules. In comparison with PTD, CTP and its fusion partners exhibited a clear preference for cytoplasmic localization, and also markedly enhanced membrane transduction potential. Unlike the mechanism underlying PTD-mediated transduction, CTP-mediated transduction occurs independently of the lipid raft-dependent macropinocytosis pathway. The CTP-conjugated Smac/DIABLO peptide (Smac-CTP) was also shown to be much more efficient than Smac-PTD in the blockage of the antiapoptotic properties of XIAP, suggesting that cytoplasmic functional molecules can be more efficiently targeted by CTP-mediated delivery. In in vivo trafficking studies, CTP-fused β-gal exhibited unique organ tropisms to the liver and lymph nodes when systemically injected into mice, whereas PTD-β-gal exhibited no such tropisms. Taken together, our findings implicate CTP as a novel delivery peptide appropriate for (i) molecular targeting to cytoplasmic compartments in vitro, (ii) the development of class I-associated CTL vaccines, and (iii) special drug delivery in vivo, without causing any untoward effects on nuclear genetic material

  19. Subcellular impact of sonoporation on plant cells: issues to be addressed in ultrasound-mediated gene transfer.

    Science.gov (United States)

    Qin, Peng; Xu, Lin; Cai, Ping; Hu, Yaxin; Yu, Alfred C H

    2013-01-01

    Sonoporation (membrane perforation via ultrasonic cavitation) is known to be realizable in plant cells on a reversible basis. However, cell viability may concomitantly be affected over the process, and limited knowledge is now available on how such cytotoxic impact comes about. This work has investigated how sonoporation may affect plant cells at a subcellular level and in turn activate programmed cell death (PCD). Tobacco BY-2 cells were used as the plant model, and sonoporation was applied through a microbubble-mediated approach with 100:1 cell-to-bubble ratio, free-field peak rarefaction pressure of either 0.4 or 0.9 MPa, and 1 MHz ultrasound frequency (administered in pulsed standing-wave mode at 10% duty cycle, 1 kHz pulse repetition frequency, and 1 min duration). Fluoroscopy results showed that sonoporated tobacco cells may undergo plasma membrane depolarization and reactive oxygen species elevation (two cellular disruption events closely connected to PCD). It was also found that the mitochondria of sonoporated tobacco cells may lose their outer membrane potential over time (observed using confocal microscopy) and consequently release stores of cytochrome-c proteins (determined by Western Blotting) into the cytoplasm to activate PCD. These findings provide insight into the underlying mechanisms responsible for sonoporation-induced cytotoxicity in plant cells. They should be taken into account when using this membrane perforation approach for gene transfection applications in plant biotechnology. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. 2012 Gordon Research Conference, Mitochondria and Chloroplasts, July 29 - Aug 3 2012

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, Alice [Univ. of Oregon, Eugene, OR (United States)

    2012-08-03

    The 2012 Gordon Research Conference on Mitochondria and Chloroplasts will assemble an international group of scientists investigating fundamental properties of these organelles, and their integration into broader physiological processes. The conference will emphasize the many commonalities between mitochondria and chloroplasts: their evolution from bacterial endosymbionts, their genomes and gene expression systems, their energy transducing membranes whose proteins derive from both nuclear and organellar genes, the challenge of maintaining organelle integrity in the presence of the reactive oxygen species that are generated during energy transduction, their incorporation into organismal signaling pathways, and more. The conference will bring together investigators working in animal, plant, fungal and protozoan systems who specialize in cell biology, genetics, biochemistry, physiology, proteomics, genomics, and structural biology. As such, this conference will provide a unique forum that engenders cross-disciplinary discussions concerning the biogenesis, dynamics, and regulation of these key cellular structures. By fostering interactions among mammalian, fungal and plant organellar biologists, this conference also provides a conduit for the transmission of mechanistic insights obtained in model organisms to applications in medicine and agriculture. The 2012 conference will highlight areas that are moving rapidly and emerging themes. These include new insights into the ultrastructure and organization of the energy transducing membranes, the coupling of organellar gene expression with the assembly of photosynthetic and respiratory complexes, the regulatory networks that couple organelle biogenesis with developmental and physiological signals, the signaling events through which organellar physiology influences nuclear gene expression, and the roles of organelles in disease and development.

  1. Genetics and biology of cytoplasmic male sterility (CMS) and its applications in forage and turf grass breeding

    OpenAIRE

    Islam Mohamed Shofiqul; Studer Bruno; Møller Ian Max; Asp Torben

    2014-01-01

    Hybrid breeding can exploit heterosis and thus offers opportunities to maximize yield quality and resistance traits in crop species. Cytoplasmic male sterility (CMS) is a widely applied tool for efficient hybrid seed production. Encoded in the mitochondrial genome CMS is maternally inherited and thus it can be challenging to apply in breeding schemes of allogamous self incompatible plant species such as perennial ryegrass. Starting with a general introduction to the origin and the function of...

  2. Mutagenesis-based research aimed at obtaining resistance to Helminthosporium maydis, straint T, in maize with Texas male sterile cytoplasm

    International Nuclear Information System (INIS)

    Cornu, A.; Vuillaume, E.; Cassini, R.; Berville, A.

    1977-01-01

    Mutagenesis was used on the French line F7T, with Texas male sterile cytoplasm, in order to obtain plants resistant to Helminthosporium maydis. The M 3 seedlings were screened for resistance either by using a fungus culture filtrate or through contamination with the fungus itself. In the first tests, carried out after the seeds had been treated with an aqueous solution of EMS, a number of families exhibiting original types of resistance to Helminthosporium maydis, strain T, were isolated. (author)

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Animal models of antineutrophil cytoplasm antibody-associated vasculitis.

    LENUS (Irish Health Repository)

    Salama, Alan D

    2012-01-01

    To provide an update on the experimental models that have been developed recapitulating clinical antineutrophil cytoplasm antibody (ANCA) associated vasculitis. The application of the models in the study of pathogenesis, and the therapeutic implications of this, are covered in the article by van Timmeren and Heeringa in this issue.

  8. Nuclear proteins hijacked by mammalian cytoplasmic plus strand RNA viruses

    International Nuclear Information System (INIS)

    Lloyd, Richard E.

    2015-01-01

    Plus strand RNA viruses that replicate in the cytoplasm face challenges in supporting the numerous biosynthetic functions required for replication and propagation. Most of these viruses are genetically simple and rely heavily on co-opting cellular proteins, particularly cellular RNA-binding proteins, into new roles for support of virus infection at the level of virus-specific translation, and building RNA replication complexes. In the course of infectious cycles many nuclear-cytoplasmic shuttling proteins of mostly nuclear distribution are detained in the cytoplasm by viruses and re-purposed for their own gain. Many mammalian viruses hijack a common group of the same factors. This review summarizes recent gains in our knowledge of how cytoplasmic RNA viruses use these co-opted host nuclear factors in new functional roles supporting virus translation and virus RNA replication and common themes employed between different virus groups. - Highlights: • Nuclear shuttling host proteins are commonly hijacked by RNA viruses to support replication. • A limited group of ubiquitous RNA binding proteins are commonly hijacked by a broad range of viruses. • Key virus proteins alter roles of RNA binding proteins in different stages of virus replication

  9. The transmission of cytoplasmic genes in Aspergillus nidulans

    NARCIS (Netherlands)

    Coenen, A.

    1997-01-01


    Introduction

    This manuscript concerns the spread of selfish cytoplasmic genes in the fungus Aspergillus nidulans. A.nidulans is a common soil fungus that grows vegetatively by forming a network (mycelium) of hyphae and reproduces

  10. Cytoplasmic Domains and Voltage-Dependent Potassium Channel Gating

    Science.gov (United States)

    Barros, Francisco; Domínguez, Pedro; de la Peña, Pilar

    2012-01-01

    The basic architecture of the voltage-dependent K+ channels (Kv channels) corresponds to a transmembrane protein core in which the permeation pore, the voltage-sensing components and the gating machinery (cytoplasmic facing gate and sensor–gate coupler) reside. Usually, large protein tails are attached to this core, hanging toward the inside of the cell. These cytoplasmic regions are essential for normal channel function and, due to their accessibility to the cytoplasmic environment, constitute obvious targets for cell-physiological control of channel behavior. Here we review the present knowledge about the molecular organization of these intracellular channel regions and their role in both setting and controlling Kv voltage-dependent gating properties. This includes the influence that they exert on Kv rapid/N-type inactivation and on activation/deactivation gating of Shaker-like and eag-type Kv channels. Some illustrative examples about the relevance of these cytoplasmic domains determining the possibilities for modulation of Kv channel gating by cellular components are also considered. PMID:22470342

  11. Actin polymerisation at the cytoplasmic face of eukaryotic nuclei

    Directory of Open Access Journals (Sweden)

    David-Watine Brigitte

    2006-05-01

    Full Text Available Abstract Background There exists abundant molecular and ultra-structural evidence to suggest that cytoplasmic actin can physically interact with the nuclear envelope (NE membrane system. However, this interaction has yet to be characterised in living interphase cells. Results Using a fluorescent conjugate of the actin binding drug cytochalasin D (CD-BODIPY we provide evidence that polymerising actin accumulates in vicinity to the NE. In addition, both transiently expressed fluorescent actin and cytoplasmic micro-injection of fluorescent actin resulted in accumulation of actin at the NE-membrane. Consistent with the idea that the cytoplasmic phase of NE-membranes can support this novel pool of perinuclear actin polymerisation we show that isolated, intact, differentiated primary hepatocyte nuclei support actin polymerisation in vitro. Further this phenomenon was inhibited by treatments hindering steric access to outer-nuclear-membrane proteins (e.g. wheat germ agglutinin, anti-nesprin and anti-nucleoporin antibodies. Conclusion We conclude that actin polymerisation occurs around interphase nuclei of living cells at the cytoplasmic phase of NE-membranes.

  12. Experimental Analysis of Cell Function Using Cytoplasmic Streaming

    Science.gov (United States)

    Janssens, Peter; Waldhuber, Megan

    2012-01-01

    This laboratory exercise investigates the phenomenon of cytoplasmic streaming in the fresh water alga "Nitella". Students use the fungal toxin cytochalasin D, an inhibitor of actin polymerization, to investigate the mechanism of streaming. Students use simple statistical methods to analyze their data. Typical student data are provided. (Contains 3…

  13. Endoplasmic-reticulum-mediated microtubule alignment governs cytoplasmic streaming.

    Science.gov (United States)

    Kimura, Kenji; Mamane, Alexandre; Sasaki, Tohru; Sato, Kohta; Takagi, Jun; Niwayama, Ritsuya; Hufnagel, Lars; Shimamoto, Yuta; Joanny, Jean-François; Uchida, Seiichi; Kimura, Akatsuki

    2017-04-01

    Cytoplasmic streaming refers to a collective movement of cytoplasm observed in many cell types. The mechanism of meiotic cytoplasmic streaming (MeiCS) in Caenorhabditis elegans zygotes is puzzling as the direction of the flow is not predefined by cell polarity and occasionally reverses. Here, we demonstrate that the endoplasmic reticulum (ER) network structure is required for the collective flow. Using a combination of RNAi, microscopy and image processing of C. elegans zygotes, we devise a theoretical model, which reproduces and predicts the emergence and reversal of the flow. We propose a positive-feedback mechanism, where a local flow generated along a microtubule is transmitted to neighbouring regions through the ER. This, in turn, aligns microtubules over a broader area to self-organize the collective flow. The proposed model could be applicable to various cytoplasmic streaming phenomena in the absence of predefined polarity. The increased mobility of cortical granules by MeiCS correlates with the efficient exocytosis of the granules to protect the zygotes from osmotic and mechanical stresses.

  14. Magnetite nanoparticles as reporters for microcarrier processing in cytoplasm

    Energy Technology Data Exchange (ETDEWEB)

    Reibetanz, Uta, E-mail: uta.reibetanz@medizin.uni-leipzig.de [Translational Centre for Regenerative Medicine (TRM) Leipzig, Universitaet Leipzig, Philipp-Rosenthal-Strasse 55, 04103 Leipzig (Germany); Institute for Medical Physics and Biophysics, Medical Faculty, Universitaet Leipzig, Haertelstrasse 16-18, 04107 Leipzig (Germany); Jankuhn, Steffen, E-mail: jankuhn@uni-leipzig.de [Division of Nuclear Solid State Physics, Faculty of Physics and Geosciences, Universitaet Leipzig, Linnestrasse 5, 04103 Leipzig (Germany); Office for Environmental Protection and Occupational Safety, Universitaet Leipzig, Ritterstrasse 24, 04109 Leipzig (Germany)

    2011-10-15

    The development and therapeutic application of drug delivery systems based on colloidal microcarriers layer-by-layer coated with biopolyelectrolytes requires the investigation of their processing inside the cell for the successful and efficient transport and release of the active agents. The present study is focused on the time-dependent multilayer decomposition and the subsequent release of active agents to the cytoplasm. Magnetite nanoparticles (MNP) were used as reporter agents integrated into the protamine sulfate/dextran sulfate basis multilayer on colloidal SiO{sub 2} cores. This functionalization allows the monitoring of the multilayer decomposition due to the detection of the MNP release, visualized by means of proton-induced X-ray emission (PIXE) by elemental distribution of Si and Fe. The direct correlation between the microcarrier localization in endolysosomes and cytoplasm of HEK293T/17 cells via confocal laser scanning microscopy (CLSM) and the elemental distribution (PIXE) allows tracing the fate of the MNP-coated microcarriers in cytoplasm, and thus the processing of the multilayer. Microcarrier/cell co-incubation experiments of 6 h, 24 h, 48 h, and 72 h show that a MNP release and a slight expansion into the cytoplasm occurs after a longer co-incubation of 72 h.

  15. Stabilization and Degradation Mechanisms of Cytoplasmic Ataxin-1

    Directory of Open Access Journals (Sweden)

    Mayumi F. Kohiyama

    2015-01-01

    Full Text Available Aggregation-prone proteins in neurodegenerative disease disrupt cellular protein stabilization and degradation pathways. The neurodegenerative disease spinocerebellar ataxia type 1 (SCA1 is caused by a coding polyglutamine expansion in the Ataxin-1 gene ( ATXN1 , which gives rise to the aggregation-prone mutant form of ATXN1 protein. Cerebellar Purkinje neurons, preferentially vulnerable in SCA1, produce ATXN1 protein in both cytoplasmic and nuclear compartments. Cytoplasmic stabilization of ATXN1 by phosphorylation and 14-3-3-mediated mechanisms ultimately drive translocation of the protein to the nucleus where aggregation may occur. However, experimental inhibition of phosphorylation and 14-3-3 binding results in rapid degradation of ATXN1, thus preventing nuclear translocation and cellular toxicity. The exact mechanism of cytoplasmic ATXN1 degradation is currently unknown; further investigation of degradation may provide future therapeutic targets. This review examines the present understanding of cytoplasmic ATXN1 stabilization and potential degradation mechanisms during normal and pathogenic states.

  16. Cytoplasmic tail of coronavirus spike protein has intracellular

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/jbsc/042/02/0231-0244. Keywords. Coronavirus spike protein trafficking; cytoplasmic tail signal; endoplasmic reticulum–Golgi intermediate complex; lysosome. Abstract. Intracellular trafficking and localization studies of spike protein from SARS and OC43 showed that SARS spikeprotein is ...

  17. Nuclear proteins hijacked by mammalian cytoplasmic plus strand RNA viruses

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, Richard E., E-mail: rlloyd@bcm.edu

    2015-05-15

    Plus strand RNA viruses that replicate in the cytoplasm face challenges in supporting the numerous biosynthetic functions required for replication and propagation. Most of these viruses are genetically simple and rely heavily on co-opting cellular proteins, particularly cellular RNA-binding proteins, into new roles for support of virus infection at the level of virus-specific translation, and building RNA replication complexes. In the course of infectious cycles many nuclear-cytoplasmic shuttling proteins of mostly nuclear distribution are detained in the cytoplasm by viruses and re-purposed for their own gain. Many mammalian viruses hijack a common group of the same factors. This review summarizes recent gains in our knowledge of how cytoplasmic RNA viruses use these co-opted host nuclear factors in new functional roles supporting virus translation and virus RNA replication and common themes employed between different virus groups. - Highlights: • Nuclear shuttling host proteins are commonly hijacked by RNA viruses to support replication. • A limited group of ubiquitous RNA binding proteins are commonly hijacked by a broad range of viruses. • Key virus proteins alter roles of RNA binding proteins in different stages of virus replication.

  18. Intracellular position of mitochondria and chloroplasts in bundle sheath and mesophyll cells of C3 grasses in relation to photorespiratory CO2 loss

    Directory of Open Access Journals (Sweden)

    Yuto Hatakeyama

    2016-10-01

    Full Text Available In C3 plants, photosynthetic efficiency is reduced by photorespiration. A part of CO2 fixed during photosynthesis in chloroplasts is lost from mitochondria during photorespiration by decarboxylation of glycine by glycine decarboxylase (GDC. Thus, the intracellular position of mitochondria in photosynthetic cells is critical to the rate of photorespiratory CO2 loss. We investigated the intracellular position of mitochondria in parenchyma sheath (PS and mesophyll cells of 10 C3 grasses from 3 subfamilies (Ehrhartoideae, Panicoideae, and Pooideae by immunostaining for GDC and light and electron microscopic observation. Immunostaining suggested that many mitochondria were located in the inner half of PS cells and on the vacuole side of chloroplasts in mesophyll cells. Organelle quantification showed that 62–75% of PS mitochondria were located in the inner half of cells, and 62–78% of PS chloroplasts were in the outer half. In mesophyll cells, 61–92% of mitochondria were positioned on the vacuole side of chloroplasts and stromules. In PS cells, such location would reduce the loss of photorespiratory CO2 by lengthening the path of CO2 diffusion and allow more efficient fixation of CO2 from intercellular spaces. In mesophyll cells, it would facilitate scavenging by chloroplasts of photorespiratory CO2 released from mitochondria. Our data suggest that the PS cells of C3 grasses have already acquired an initial structure leading to proto-Kranz and further C3–C4 intermediate anatomy. We also found that in the Pooideae, organelle positioning in PS cells on the phloem side resembles that in mesophyll cells.

  19. 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.

  20. 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.

  1. [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.

  2. 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....

  3. 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.

  4. Analysis of embryo, cytoplasm and maternal effects on fatty acid components in soybean (Glycine max Merill.)

    Institute of Scientific and Technical Information of China (English)

    NING Hailong; LI Wenxia; LI Wenbin

    2007-01-01

    The quality of oil determined by the constituents and proportion of fatty acid components,and the understanding of heredity of fatty acid components are of importance to breeding good quality soybean varieties.Embryo,cytoplasmic and maternal effects and genotype×environment interaction effects for quality traits of soybean [Glycine max (L.) Merrill.] seeds were analyzed using a general genetic model for quantitative traits of seeds with parents,F1 and F2,of 20 crosses from a diallel mating design of five parents planted in the field in 2003 and 2004 in Harbin,China.The interaction effects of palmitic,stearic,and linoleic acid contents were larger than the genetic main effects,while the genetic main effects were equal to interaction effects for linolenic and oleic acid content.Among all kinds of genetic main effects,the embryo effects were the largest for palmitic,stearic,and linoleic acids,while the cytoplasm effects were the largest for oleic and linolenic acids.Among all kinds of interaction effects,the embryo interaction effects were the largest for fatty acids.The sum of additive and additive× environment effects were larger than that of dominance and dominance×environment effects for the linolenic acid content,but not for other quality traits.The general heritabilities were the main parts of heritabilities for palmitic and oleic acid contents,but the interaction was more important for stearic,linoleic,and linolenic acid contents.For the general heritability,maternal and cytoplasm heritabilities were the main components for palmitic,oleic,and linolenic acid contents.It was shown for the interaction heritabilities that the embryo interaction heritabilities were more important for oleic and linolenic acid contents,while the maternal interaction heritabilities were more important for linoleic acid content.Among selection response components,the maternal and cytoplasm general responses and/or interaction responses were more important for palmitic

  5. 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.

  6. Ginsenoside Rb1 Attenuates Oxygen-Glucose Deprivation-Induced Apoptosis in SH-SY5Y Cells via Protection of Mitochondria and Inhibition of AIF and Cytochrome c Release

    Directory of Open Access Journals (Sweden)

    Pengfei Ge

    2013-10-01

    Full Text Available To investigate the role of mitochondria in the protective effects of ginsenoside Rb1 on cellular apoptosis caused by oxygen-glucose deprivation, in this study, MTT assay, TUNEL staining, flow cytometry, immunocytochemistry and western blotting were used to examine the cellular viability, apoptosis, ROS level, mitochondrial membrane potential, and the distribution of apoptosis inducing factor, cytochrome c, Bax and Bcl-2 in nucleus, mitochondria and cytoplasm. We found that pretreatment with GRb1 improved the cellular viability damaged by OGD. Moreover, GRb1 inhibited apoptosis in SH-SY5Y cells induced by OGD. Further studies showed that the elevation of cellular reactive oxygen species levels and the reduction of mitochondrial membrane potential caused by OGD were both counteracted by GRb1. Additionally, GRb1 not only suppressed the translocation of apoptosis inducing factor into nucleus and cytochrome c into cytoplasm, but also inhibited the increase of Bax within mitochondria and alleviated the decrease of mitochondrial Bcl-2. Our study indicates that the protection of GRb1 on OGD-induced apoptosis in SH-SY5Y cells is associated with its protection on mitochondrial function and inhibition of release of AIF and cytochrome c.

  7. 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

  8. First cytoplasmic loop of glucagon-like peptide-1 receptor can function at the third cytoplasmic loop position of rhodopsin.

    Science.gov (United States)

    Yamashita, Takahiro; Tose, Koji; Shichida, Yoshinori

    2008-01-01

    G protein-coupled receptors (GPCRs) are classified into several families based on their amino acid sequences. In family 1, GPCRs such as rhodopsin and adrenergic receptor, the structure-function relationship has been extensively investigated to demonstrate that exposure of the third cytoplasmic loop is essential for selective G protein activation. In contrast, much less is known about other families. Here we prepared chimeric mutants between Gt-coupled rhodopsin and Gi/Go- and Gs-coupled glucagon-like peptide-1 (GLP-1) receptor of family 2 and tried to identify the loop region that functions at the third cytoplasmic loop position of rhodopsin. We succeeded in expressing a mutant having the first cytoplasmic loop of GLP-1 receptor and found that this mutant activated Gi and Go efficiently but did not activate Gt. Moreover, the rhodopsin mutant having the first loop of Gs-coupled secretin receptor of family 2 decreased the Gi and Go activation efficiencies. Therefore, the first loop of GLP-1 receptor would share a similar role to the third loop of rhodopsin in G protein activation. This result strongly suggested that different families of GPCRs have maintained molecular architectures of their ancestral types to generate a common mechanism, namely exposure of the cytoplasmic loop, to activate peripheral G protein.

  9. 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...

  10. 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

  11. Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes

    Science.gov (United States)

    Johannes, E.; Collings, D. A.; Rink, J. C.; Allen, N. S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

  12. Mitochondrial Iron Transport and Homeostasis in Plants

    Directory of Open Access Journals (Sweden)

    Anshika eJain

    2013-09-01

    Full Text Available Iron (Fe is an essential nutrient for plants and although the mechanisms controlling iron uptake from the soil are relatively well understood, comparatively little is known about subcellular trafficking of iron in plant cells. Mitochondria represent a significant iron sink within cells, as iron is required for the proper functioning of respiratory chain protein complexes. Mitochondria are a site of Fe-S cluster synthesis, and possibly heme synthesis as well. Here we review recent insights into the molecular mechanisms controlling mitochondrial iron transport and homeostasis. We focus on the recent identification of a mitochondrial iron uptake transporter in rice and a possible role for metalloreductases in iron uptake by mitochondria. In addition, we highlight recent advances in mitochondrial iron homeostasis with an emphasis on the roles of frataxin and ferritin in iron trafficking and storage within mitochondria.

  13. Upon Infection the Cellular WD Repeat-containing Protein 5 (WDR5) Localizes to Cytoplasmic Inclusion Bodies and Enhances Measles Virus Replication.

    Science.gov (United States)

    Ma, Dzwokai; George, Cyril X; Nomburg, Jason; Pfaller, Christian K; Cattaneo, Roberto; Samuel, Charles E

    2017-12-13

    Replication of negative-strand RNA viruses occurs in association with discrete cytoplasmic foci called inclusion bodies. Whereas inclusion bodies represent a prominent subcellular structure induced by viral infection, our knowledge of the cellular protein components involved in inclusion body formation and function is limited. Using measles virus-infected HeLa cells, we found that the WD repeat-containing protein 5 (WDR5), a subunit of histone H3 lysine 4 methyltransferases, was selectively recruited to virus-induced inclusion bodies. Furthermore, WDR5 was found in complexes containing viral proteins associated with RNA replication. WDR5 was not detected with mitochondria, stress granules, or other known secretory or endocytic compartments of infected cells. WDR5 deficiency decreased both viral protein production and infectious virus yields. Interferon production was modestly increased in WDR5 deficient cells. Thus, our study identifies WDR5 as a novel viral inclusion body-associated cellular protein and suggests a role for WDR5 in promoting viral replication. IMPORTANCE Measles virus is a human pathogen that remains a global concern with more than 100,000 measles-related deaths annually despite the availability of an effective vaccine. As measles continues to cause significant morbidity and mortality, understanding the virus-host interactions at the molecular level that affect virus replication efficiency is important for development and optimization of treatment procedures. Measles virus is an RNA virus that encodes six genes and replicates in the cytoplasm of infected cells in discrete cytoplasmic replication bodies, though little is known of the biochemical nature of these structures. Here we show that the cellular protein WDR5 is enriched in the cytoplasmic viral replication factories and enhances virus growth. WDR5-containing protein complex includes viral proteins responsible for viral RNA replication. Thus, we have identified WDR5 as a host factor that

  14. Genetic analysis of the cytoplasmic dynein subunit families.

    Science.gov (United States)

    Pfister, K Kevin; Shah, Paresh R; Hummerich, Holger; Russ, Andreas; Cotton, James; Annuar, Azlina Ahmad; King, Stephen M; Fisher, Elizabeth M C

    2006-01-01

    Cytoplasmic dyneins, the principal microtubule minus-end-directed motor proteins of the cell, are involved in many essential cellular processes. The major form of this enzyme is a complex of at least six protein subunits, and in mammals all but one of the subunits are encoded by at least two genes. Here we review current knowledge concerning the subunits, their interactions, and their functional roles as derived from biochemical and genetic analyses. We also carried out extensive database searches to look for new genes and to clarify anomalies in the databases. Our analysis documents evolutionary relationships among the dynein subunits of mammals and other model organisms, and sheds new light on the role of this diverse group of proteins, highlighting the existence of two cytoplasmic dynein complexes with distinct cellular roles.

  15. Genetic analysis of the cytoplasmic dynein subunit families.

    Directory of Open Access Journals (Sweden)

    K Kevin Pfister

    2006-01-01

    Full Text Available Cytoplasmic dyneins, the principal microtubule minus-end-directed motor proteins of the cell, are involved in many essential cellular processes. The major form of this enzyme is a complex of at least six protein subunits, and in mammals all but one of the subunits are encoded by at least two genes. Here we review current knowledge concerning the subunits, their interactions, and their functional roles as derived from biochemical and genetic analyses. We also carried out extensive database searches to look for new genes and to clarify anomalies in the databases. Our analysis documents evolutionary relationships among the dynein subunits of mammals and other model organisms, and sheds new light on the role of this diverse group of proteins, highlighting the existence of two cytoplasmic dynein complexes with distinct cellular roles.

  16. Amorphous areas in the cytoplasm of Dendrobium tepal cells

    Science.gov (United States)

    van Doorn, Wouter G.; Kirasak, Kanjana; Ketsa, Saichol

    2013-01-01

    In Dendrobium flowers some tepal mesophyll cells showed cytoplasmic areas devoid of large organelles. Such amorphous areas comprised up to about 40% of the cross-section of a cell. The areas were not bound by a membrane. The origin of these areas is not known. We show data suggesting that they can be formed from vesicle-like organelles. The data imply that these organelles and other material become degraded inside the cytoplasm. This can be regarded as a form of autophagy. The amorphous areas became surrounded by small vacuoles, vesicles or double membranes. These seemed to merge and thereby sequester the areas. Degradation of the amorphous areas therefore seemed to involve macroautophagy. PMID:23823702

  17. 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.

  18. 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.

  19. 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, ...

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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...

  5. 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...

  6. 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.

  7. 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 ...

  8. Algorithms for Cytoplasm Segmentation of Fluorescence Labelled Cells

    OpenAIRE

    Carolina Wählby; Joakim Lindblad; Mikael Vondrus; Ewert Bengtsson; Lennart Björkesten

    2002-01-01

    Automatic cell segmentation has various applications in cytometry, and while the nucleus is often very distinct and easy to identify, the cytoplasm provides a lot more challenge. A new combination of image analysis algorithms for segmentation of cells imaged by fluorescence microscopy is presented. The algorithm consists of an image pre?processing step, a general segmentation and merging step followed by a segmentation quality measurement. The quality measurement consists of a statistical ana...

  9. Nucleoporin Nup98 mediates galectin-3 nuclear-cytoplasmic trafficking

    Energy Technology Data Exchange (ETDEWEB)

    Funasaka, Tatsuyoshi, E-mail: funasaka@staff.kanazawa-u.ac.jp [Laboratory of Molecular and Cellular Biology, Department of Biology, Faculty of Natural Systems, Institute of Science and Engineering, Kanazawa University, Ishikawa (Japan); Balan, Vitaly; Raz, Avraham [Department of Oncology and Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI (United States); Wong, Richard W., E-mail: rwong@staff.kanazawa-u.ac.jp [Laboratory of Molecular and Cellular Biology, Department of Biology, Faculty of Natural Systems, Institute of Science and Engineering, Kanazawa University, Ishikawa (Japan); Bio-AFM Frontier Research Center, Kanazawa Kanazawa University, Ishikawa (Japan)

    2013-04-26

    Highlights: •Nuclear pore protein Nup98 is a novel binding partner of galectin-3. •Nup98 transports galectin-3 into cytoplasm. •Nup98 depletion leads to galectin-3 nuclear transport and induces growth retardation. •Nup98 may involve in ß-catenin pathway through interaction with galectin-3. -- Abstract: Nucleoporin Nup98 is a component of the nuclear pore complex, and is important in transport across the nuclear pore. Many studies implicate nucleoporin in cancer progression, but no direct mechanistic studies of its effect in cancer have been reported. We show here that Nup98 specifically regulates nucleus–cytoplasm transport of galectin-3, which is a ß-galactoside-binding protein that affects adhesion, migration, and cancer progression, and controls cell growth through the ß-catenin signaling pathway in cancer cells. Nup98 interacted with galectin-3 on the nuclear membrane, and promoted galectin-3 cytoplasmic translocation whereas other nucleoporins did not show these functions. Inversely, silencing of Nup98 expression by siRNA technique localized galectin-3 to the nucleus and retarded cell growth, which was rescued by Nup98 transfection. In addition, Nup98 RNA interference significantly suppressed downstream mRNA expression in the ß-catenin pathway, such as cyclin D1 and FRA-1, while nuclear galectin-3 binds to ß-catenin to inhibit transcriptional activity. Reduced expression of ß-catenin target genes is consistent with the Nup98 reduction and the galectin-3–nucleus translocation rate. Overall, the results show Nup98’s involvement in nuclear–cytoplasm translocation of galectin-3 and ß-catenin signaling pathway in regulating cell proliferation, and the results depicted here suggest a novel therapeutic target/modality for cancers.

  10. 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

  11. Mutant p53 protein localized in the cytoplasm inhibits autophagy.

    Science.gov (United States)

    Morselli, Eugenia; Tasdemir, Ezgi; Maiuri, Maria Chiara; Galluzzi, Lorenzo; Kepp, Oliver; Criollo, Alfredo; Vicencio, José Miguel; Soussi, Thierry; Kroemer, Guido

    2008-10-01

    The knockout, knockdown or chemical inhibition of p53 stimulates autophagy. Moreover, autophagy-inducing stimuli such as nutrient depletion, rapamycin or lithium cause the depletion of cytoplasmic p53, which in turn is required for the induction of autophagy. Here, we show that retransfection of p53(-/-) HCT 116 colon carcinoma cells with wild type p53 decreases autophagy down to baseline levels. Surprisingly, one third among a panel of 22 cancer-associated p53 single amino acid mutants also inhibited autophagy when transfected into p53(-/-) cells. Those variants of p53 that preferentially localize to the cytoplasm effectively repressed autophagy, whereas p53 mutants that display a prominently nuclear distribution failed to inhibit autophagy. The investigation of a series of deletion mutants revealed that removal of the DNA-binding domain from p53 fails to interfere with its role in the regulation of autophagy. Altogether, these results identify the cytoplasmic localization of p53 as the most important feature for p53-mediated autophagy inhibition. Moreover, the structural requirements for the two biological activities of extranuclear p53, namely induction of apoptosis and inhibition of autophagy, are manifestly different.

  12. Cytoplasmic Control of Sense-Antisense mRNA Pairs

    Directory of Open Access Journals (Sweden)

    Flore Sinturel

    2015-09-01

    Full Text Available Transcriptome analyses have revealed that convergent gene transcription can produce many 3′-overlapping mRNAs in diverse organisms. Few studies have examined the fate of 3′-complementary mRNAs in double-stranded RNA-dependent nuclear phenomena, and nothing is known about the cytoplasmic destiny of 3′-overlapping messengers or their impact on gene expression. Here, we demonstrate that the complementary tails of 3′-overlapping mRNAs can interact in the cytoplasm and promote post-transcriptional regulatory events including no-go decay (NGD in Saccharomyces cerevisiae. Genome-wide experiments confirm that these messenger-interacting mRNAs (mimRNAs form RNA duplexes in wild-type cells and thus have potential roles in modulating the mRNA levels of their convergent gene pattern under different growth conditions. We show that the post-transcriptional fate of hundreds of mimRNAs is controlled by Xrn1, revealing the extent to which this conserved 5′-3′ cytoplasmic exoribonuclease plays an unexpected but key role in the post-transcriptional control of convergent gene expression.

  13. Cytoplasmic Control of Sense-Antisense mRNA Pairs.

    Science.gov (United States)

    Sinturel, Flore; Navickas, Albertas; Wery, Maxime; Descrimes, Marc; Morillon, Antonin; Torchet, Claire; Benard, Lionel

    2015-09-22

    Transcriptome analyses have revealed that convergent gene transcription can produce many 3'-overlapping mRNAs in diverse organisms. Few studies have examined the fate of 3'-complementary mRNAs in double-stranded RNA-dependent nuclear phenomena, and nothing is known about the cytoplasmic destiny of 3'-overlapping messengers or their impact on gene expression. Here, we demonstrate that the complementary tails of 3'-overlapping mRNAs can interact in the cytoplasm and promote post-transcriptional regulatory events including no-go decay (NGD) in Saccharomyces cerevisiae. Genome-wide experiments confirm that these messenger-interacting mRNAs (mimRNAs) form RNA duplexes in wild-type cells and thus have potential roles in modulating the mRNA levels of their convergent gene pattern under different growth conditions. We show that the post-transcriptional fate of hundreds of mimRNAs is controlled by Xrn1, revealing the extent to which this conserved 5'-3' cytoplasmic exoribonuclease plays an unexpected but key role in the post-transcriptional control of convergent gene expression. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Cytoplasmic streaming in Drosophila oocytes varies with kinesin activity and correlates with the microtubule cytoskeleton architecture.

    Science.gov (United States)

    Ganguly, Sujoy; Williams, Lucy S; Palacios, Isabel M; Goldstein, Raymond E

    2012-09-18

    Cells can localize molecules asymmetrically through the combined action of cytoplasmic streaming, which circulates their fluid contents, and specific anchoring mechanisms. Streaming also contributes to the distribution of nutrients and organelles such as chloroplasts in plants, the asymmetric position of the meiotic spindle in mammalian embryos, and the developmental potential of the zygote, yet little is known quantitatively about the relationship between streaming and the motor activity which drives it. Here we use Particle Image Velocimetry to quantify the statistical properties of Kinesin-dependent streaming during mid-oogenesis in Drosophila. We find that streaming can be used to detect subtle changes in Kinesin activity and that the flows reflect the architecture of the microtubule cytoskeleton. Furthermore, based on characterization of the rheology of the cytoplasm in vivo, we establish estimates of the number of Kinesins required to drive the observed streaming. Using this in vivo data as the basis of a model for transport, we suggest that the disordered character of transport at mid-oogenesis, as revealed by streaming, is an important component of the localization dynamics of the body plan determinant oskar mRNA.

  15. Effect of physical and chemical mutagens and male sterile cytoplasm of chaisma frequency in pearl millet inbreds and hybrids

    International Nuclear Information System (INIS)

    Singh, B.D.; Singh, R.B.; Singh, R.M.; Vijay Laxmi

    1977-01-01

    Chiasma frequency was recorded in normal and treated [10, 20, 30 Kr γ-rays, 0.2% ethyl methane-sulphonate (EMS) and 10 Kr γ-rays + 0.2% EMS] populations of 7 inbreds and 3 hybrids of pearl millet. Inbreds in general showed lower chiasma frequency than hybrids. However, inbred Bi13B showed the highest chiasma frequency. The male sterile cytoplasm reduced the chaisma frequency and increased the among-plant-variability in the inbreds and, therefore, possibly in the hybrids which had male sterile cytoplasm. γ-rays were more effective than EMS in reducing chiasma frequency. In most of the genotypes 10Kr γ-rays and 0.2% EMS promoted chiasma frequency. The combination treatments showed greater effect than γ-rays and EMS applied individually. Hybrids as a group, showed lower variation for chiasma number than inbreds in response to the mutagenic treatments. (author)

  16. The effect of ionizing irradiation on motion of cytoplasm in cells of Elodea canadensis

    International Nuclear Information System (INIS)

    Tordyiya, N.V.; Grodzyins'kij, D.M.; Danil'chenko, O.O.

    1999-01-01

    The effect of acute irradiation on the velocity of cytoplasm is investigated. It is shown that, for small doses, there is a strong nonlinearity between the velocity of cytoplasm and dose. The nonlinear behavior disappears with increasing a dose

  17. Multi-Scale Characean Experimental System: From Electrophysiology of Membrane Transporters to Cell-to-Cell Connectivity, Cytoplasmic Streaming and Auxin Metabolism

    Science.gov (United States)

    Beilby, Mary J.

    2016-01-01

    The morphology of characean algae could be mistaken for a higher plant: stem-like axes with leaf-like branchlets anchored in the soil by root-like rhizoids. However, all of these structures are made up of giant multinucleate cells separated by multicellular nodal complexes. The excised internodal cells survive long enough for the nodes to give rise to new thallus. The size of the internodes and their thick cytoplasmic layer minimize impalement injury and allow specific micro-electrode placement. The cell structure can be manipulated by centrifugation, perfusion of cell contents or creation of cytoplasmic droplets, allowing access to both vacuolar and cytoplasmic compartments and both sides of the cell membranes. Thousands of electrical measurements on intact or altered cells and cytoplasmic droplets laid down basis to modern plant electrophysiology. Furthermore, the giant internodal cells and whole thalli facilitate research into many other plant properties. As nutrients have to be transported from rhizoids to growing parts of the thallus and hormonal signals need to pass from cell to cell, Characeae possess very fast cytoplasmic streaming. The mechanism was resolved in the characean model. Plasmodesmata between the internodal cells and nodal complexes facilitate transport of ions, nutrients and photosynthates across the nodes. The internal structure was found to be similar to those of higher plants. Recent experiments suggest a strong circadian influence on metabolic pathways producing indole-3-acetic acid (IAA) and serotonin/melatonin. The review will discuss the impact of the characean models arising from fragments of cells, single cells, cell-to-cell transport or whole thalli on understanding of plant evolution and physiology. PMID:27504112

  18. Live Cell Imaging Reveals Differential Modifications to Cytoplasmic Dynein Properties by Phospho- and Dephospho-mimic Mutations of the Intermediate Chain 2C S84

    Science.gov (United States)

    Blasier, Kiev R.; Humsi, Michael K.; Ha, Junghoon; Ross, Mitchell W.; Smiley, W. Russell; Inamdar, Nirja A.; Mitchell, David J.; Lo, Kevin W.-H.; Pfister, K. Kevin

    2014-01-01

    Cytoplasmic dynein is a multi-subunit motor protein responsible for intracellular cargo transport toward microtubule minus ends. There are multiple isoforms of the dynein intermediate chain (DYNC1I, IC) which is encoded by two genes. One way to regulate cytoplasmic dynein is by IC phosphorylation. The IC-2C isoform is expressed in all cells and the functional significance of phosphorylation on IC-2C serine 84 was investigated using live cell imaging of fluorescent protein-tagged wild type IC-2C (WT) and phospho- and dephospho-mimic mutant isoforms in axonal transport model systems. Both mutations modulated dynein functional properties. The dephospho-mimic mutant IC-2C S84A had greater co-localization with mitochondria than IC-2C wild-type (WT) or the phospho-mimic mutant IC-2C S84D. The dephospho-mimic mutant IC-2C S84A was also more likely to be motile than the phospho-mimic mutant IC-2C S84D or IC-2C WT. In contrast, the phospho-mimic mutant IC-2C S84D mutant was more likely to move in the retrograde direction than was the IC-2C S84A mutant. The phospho-mimic IC-2C S84D was also as likely as IC-2C WT to co-localize with mitochondria. Both the S84D phospho- and S84A, dephospho-mimic mutants were found to be capable of microtubule minus end directed (retrograde) movement in axons. They were also observed to be passively transported in the anterograde direction. These data suggest that the IC-2C S84 has a role in modulating dynein properties. PMID:24798412

  19. DMPD: Negative regulation of cytoplasmic RNA-mediated antiviral signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18703349 Negative regulation of cytoplasmic RNA-mediated antiviral signaling. Komur...Show Negative regulation of cytoplasmic RNA-mediated antiviral signaling. PubmedID 18703349 Title Negative r...egulation of cytoplasmic RNA-mediated antiviral signaling. Authors Komuro A, Bamm

  20. 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.

  1. 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

  2. Impacts of high ATP supply from chloroplasts and mitochondria on the leaf metabolism of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Chao eLiang

    2015-10-01

    Full Text Available Chloroplasts and mitochondria are the major ATP producing organelles in plant leaves. Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2 is a phosphatase dually targeted to the outer membranes of both organelles and it plays a role in the import of selected nuclear-encoded proteins into these two organelles. Overexpression (OE of AtPAP2 in Arabidopsis thaliana accelerates plant growth and promotes flowering, seed yield and biomass at maturity. Measurement of ADP/ATP/NADP+/NADPH contents in the leaves of 20-day-old OE and wild-type lines at the end of night and at 1 and 8 h following illumination in a 16/8 h photoperiod revealed that the ATP levels and ATP/NADPH ratios were significantly increased in the OE line at all three time points. The AtPAP2 OE line is therefore a good model to investigate the impact of high energy on the global molecular status of Arabidopsis. In this study, transcriptome, proteome and metabolome profiles of the high ATP transgenic line were examined and compared with those of wild-type plants. A comparison of OE and WT at the end of the night provide valuable information on the impact of higher ATP output from mitochondria on plant physiology, as mitochondrial respiration is the major source of ATP in the dark in leaves. Similarly, comparison of OE and WT following illumination will provide information on the impact of higher energy output from chloroplasts on plant physiology. Overexpression of AtPAP2 was found to significantly affect the transcript and protein abundances of genes encoded by the two organellar genomes. For example, the protein abundances of many ribosomal proteins encoded by the chloroplast genome were higher in the AtPAP2 OE line under both light and dark conditions, while the protein abundances of multiple components of the photosynthetic complexes were lower. RNA-seq data also showed that the transcription of the mitochondrial genome is greatly affected by the availability of energy. These data

  3. Cytoplasmic TRADD Confers a Worse Prognosis in Glioblastoma

    Directory of Open Access Journals (Sweden)

    Sharmistha Chakraborty

    2013-08-01

    Full Text Available Tumor necrosis factor receptor 1 (TNFR1-associated death domain protein (TRADD is an important adaptor in TNFR1 signaling and has an essential role in nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB activation and survival signaling. Increased expression of TRADD is sufficient to activate NF-κB. Recent studies have highlighted the importance of NF-κB activation as a key pathogenic mechanism in glioblastoma multiforme (GBM, the most common primary malignant brain tumor in adults.We examined the expression of TRADD by immunohistochemistry (IHC and find that TRADD is commonly expressed at high levels in GBM and is detected in both cytoplasmic and nuclear distribution. Cytoplasmic IHC TRADD scoring is significantly associated with worse progression-free survival (PFS both in univariate and multivariate analysis but is not associated with overall survival (n = 43 GBMs. PFS is a marker for responsiveness to treatment. We propose that TRADD-mediated NF-κB activation confers chemoresistance and thus a worse PFS in GBM. Consistent with the effect on PFS, silencing TRADD in glioma cells results in decreased NF-κB activity, decreased proliferation of cells, and increased sensitivity to temozolomide. TRADD expression is common in glioma-initiating cells. Importantly, silencing TRADD in GBM-initiating stem cell cultures results in decreased viability of stem cells, suggesting that TRADD may be required for maintenance of GBM stem cell populations. Thus, our study suggests that increased expression of cytoplasmic TRADD is both an important biomarker and a key driver of NF-κB activation in GBM and supports an oncogenic role for TRADD in GBM.

  4. Binders of intravenously administered zinc 65 in rat liver cytoplasm

    International Nuclear Information System (INIS)

    Stortenbeek, A.J.; Hamer, C.J.A. van den.

    1976-01-01

    The fate of intravenously injected trace amounts of 65 Zn 2+ in the rat was studied over a period of ten days after injection. Tissue distributions were determined and a special study was made of 65 Zn-binders in liver cytoplasm. A total of six 65 Zn-binding fractions was found and a tentative identification of the main 65 Zn-binders in these six fractions is given using the collected data regarding their apparent molecular weight, time dependent prominence and content of stable zinc

  5. AtTZF gene family localizes to cytoplasmic foci

    OpenAIRE

    Pomeranz, Marcelo; Lin, Pei-Chi; Finer, John; Jang, Jyan-Chyun

    2010-01-01

    In eukaryotes, mRNA turnover and translational repression represent important regulatory steps in gene expression. Curiously, when under cellular stresses, factors involved in these processes aggregate into cytoplasmic foci known as Processing bodies (P-bodies) and Stress Granules (SGs). In animals, CCCH Tandem Zinc Finger (TZF) proteins play important roles in mRNA decay within P-bodies. TTP, a P-body localized mammalian TZF, can bind to the 3'UTRs of mRNAs containing AU-rich elements (AREs)...

  6. [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.

  7. 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)

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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.

  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. Dose enhancement effects to the nucleus and mitochondria from gold nanoparticles in the cytosol

    Science.gov (United States)

    McNamara, AL; Kam, WW-Y; Scales, N; McMahon, SJ; Bennett, JW; Byrne, HL; Schuemann, J; Paganetti, H; Banati, R; Kuncic, Z

    2016-01-01

    Gold nanoparticles (GNPs) have shown potential as dose enhancers for radiation therapy. Since damage to the genome affects the viability of a cell, it is generally assumed that GNPs have to localise within the cell nucleus. In practice, however, GNPs tend to localise in the cytoplasm yet still appear to have a dose enhancing effect on the cell. Whether this effect can be attributed to stress-induced biological mechanisms or to physical damage to extra-nuclear cellular targets is still unclear. There is however growing evidence to suggest that the cellular response to radiation can also be influenced by indirect processes induced when the nucleus is not directly targeted by radiation. The mitochondrion in particular may be an effective extra-nuclear radiation target given its many important functional roles in the cell. To more accurately predict the physical effect of radiation within different cell organelles, we measured the full chemical composition of a whole human lymphocytic JURKAT cell as well as two separate organelles; the cell nucleus and the mitochondrion. The experimental measurements found that all three biological materials had similar ionisation energies ~ 70 eV, substantially lower than that of liquid water ~ 78 eV. Monte Carlo simulations for 10 – 50 keV incident photons showed higher energy deposition and ionisation numbers in the cell and organelle materials compared to liquid water. Adding a 1% mass fraction of gold to each material increased the energy deposition by a factor of ~ 1.8 when averaged over all incident photon energies. Simulations of a realistic compartmentalised cell show that the presence of gold in the cytosol increases the energy deposition in the mitochondrial volume more than within the nuclear volume. We find this is due to sub-micron delocalisation of energy by photoelectrons, making the mitochondria a potentially viable indirect radiation target for GNPs that localise to the cytosol. PMID:27435339

  15. Assembly of the membrane domain of ATP synthase in human mitochondria.

    Science.gov (United States)

    He, Jiuya; Ford, Holly C; Carroll, Joe; Douglas, Corsten; Gonzales, Evvia; Ding, Shujing; Fearnley, Ian M; Walker, John E

    2018-03-20

    The ATP synthase in human mitochondria is a membrane-bound assembly of 29 proteins of 18 kinds. All but two membrane components are encoded in nuclear genes, synthesized on cytoplasmic ribosomes, and imported into the matrix of the organelle, where they are assembled into the complex with ATP6 and ATP8, the products of overlapping genes in mitochondrial DNA. Disruption of individual human genes for the nuclear-encoded subunits in the membrane portion of the enzyme leads to the formation of intermediate vestigial ATPase complexes that provide a description of the pathway of assembly of the membrane domain. The key intermediate complex consists of the F 1 -c 8 complex inhibited by the ATPase inhibitor protein IF 1 and attached to the peripheral stalk, with subunits e, f, and g associated with the membrane domain of the peripheral stalk. This intermediate provides the template for insertion of ATP6 and ATP8, which are synthesized on mitochondrial ribosomes. Their association with the complex is stabilized by addition of the 6.8 proteolipid, and the complex is coupled to ATP synthesis at this point. A structure of the dimeric yeast F o membrane domain is consistent with this model of assembly. The human 6.8 proteolipid (yeast j subunit) locks ATP6 and ATP8 into the membrane assembly, and the monomeric complexes then dimerize via interactions between ATP6 subunits and between 6.8 proteolipids (j subunits). The dimers are linked together back-to-face by DAPIT (diabetes-associated protein in insulin-sensitive tissue; yeast subunit k), forming long oligomers along the edges of the cristae.

  16. 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....

  17. 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....

  18. The Genetic Variability of Floral and Agronomic Characteristics of Newly-Bred Cytoplasmic Male Sterile Rice

    Directory of Open Access Journals (Sweden)

    Raafat El-Namaky

    2018-05-01

    Full Text Available Male sterility enabled commercialization of heterosis in rice but low seed set remains a constraint on hybrid dissemination. We evaluated 216 F6 maintainer lines for agronomic and floral characteristics in augmented design and selected 15 maintainer lines, which were testcrossed with IR58025A. Five backcrosses were conducted to transfer cytoplasmic male sterility (CMS to select maintainer lines. Newly-bred BC5:6 CMS lines were evaluated for outcrossing rates and agronomic characteristics. There were highly significant differences among 216 F6 maintainer lines for characteristics whose genotypic variance was higher than environmental variance. The phenotypic coefficient of variation was almost the same as the genotypic coefficient of variation, indicating that most phenotypic variation was due to genetics. There were highly significant differences among CMS lines for number of days to 50% flowering and maturity; stigma exertion; panicle exertion, length and weight; spikelet fertility; tillers per plant; plant height; grains per panicle; grain yield per plant; and 1000-grain weight, but not for pollen and panicle sterility during dry and wet seasons. Three CMS lines (CMS3, CMS12, and CMS14, exhibited high outcrossing rates (56.17%, 51.42% and 48.44%, respectively, which had a highly significant, positive correlation with stigma exertion (0.97, spikelet opening angle (0.82, and panicle exertion (0.95.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. Chronic fluoxetine treatment directs energy metabolism towards the citric acid cycle and oxidative phosphorylation in rat hippocampal nonsynaptic mitochondria.

    Science.gov (United States)

    Filipović, Dragana; Costina, Victor; Perić, Ivana; Stanisavljević, Andrijana; Findeisen, Peter

    2017-03-15

    Fluoxetine (Flx) is the principal treatment for depression; however, the precise mechanisms of its actions remain elusive. Our aim was to identify protein expression changes within rat hippocampus regulated by chronic Flx treatment versus vehicle-controls using proteomics. Fluoxetine-hydrohloride (15mg/kg) was administered daily to adult male Wistar rats for 3weeks, and cytosolic and nonsynaptic mitochondrial hippocampal proteomes were analyzed. All differentially expressed proteins were functionally annotated according to biological process and molecular function using Uniprot and Blast2GO. Our comparative study revealed that in cytosolic and nonsynaptic mitochondrial fractions, 60 and 3 proteins respectively, were down-regulated, and 23 and 60 proteins, respectively, were up-regulated. Proteins differentially regulated in cytosolic and nonsynaptic mitochondrial fractions were primarily related to cellular and metabolic processes. Of the identified proteins, the expressions of calretinin and parvalbumine were confirmed. The predominant molecular functions of differentially expressed proteins in both cell hippocampal fractions were binding and catalytic activity. Most differentially expressed proteins in nonsynaptic mitochondria were catalytic enzymes involved in the pyruvate metabolism, citric acid cycle, oxidative phosphorylation, ATP synthesis, ATP transduction and glutamate metabolism. Results indicate that chronic Flx treatment may influence proteins involved in calcium signaling, cytoskeletal structure, chaperone system and stimulates energy metabolism via the upregulation of GAPDH expression in cytoplasm, as well as directing energy metabolism toward the citric acid cycle and oxidative phosphorylation in nonsynaptic mitochondria. This approach provides new insight into the chronic effects of Flx treatment on protein expression in a key brain region associated with stress response and memory. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Plant mitochondrial genome: “A sweet and safe home'' for transgene

    African Journals Online (AJOL)

    Aghogho

    2010-12-27

    Dec 27, 2010 ... mitochondria, transcription is mediated by at least one nuclear encoded RNA polymerase, having the RNA ... RNA editing was first discovered in plant mito- chondria (Covello and Gray, 1989; Heisel et al., ... yeast mitochondria lacking endogenous mtDNA. Proc. Natl. Acad. Sci. USA, 85: 7288-7292. Fox TD ...

  6. Protein synthesis and the recovery of both survival and cytoplasmic "petite" mutation in ultraviolet-treated yeast cells. II. Mitochondrial protein synthesis.

    Science.gov (United States)

    Heude, M; Chanet, R

    1975-04-01

    The contribution of mitochondrial proteins in the repair of UV-induced lethal and cytoplasmic genetic damages was studied in dark liquid held exponential and stationary phase yeast cells. This was performed by using the specific inhibitors, erythromycin (ER) anc chloramphenicol (CAP). It was shown that mitochondrial proteins are involved in the recovery of stationary phase cells. Mitochondrial proteins are partly implicated in the mechanisms leading to the restoration of the (see article) genotype in UV-irradiated dark liquid held exponential phase cells. Here again, in stationary phase cells, mitochondrial enzymes do not seem to participate in the negative liquid holding (NLH) process for the (see article) induction, as shown by inhibiting mitochondrial protein synthesis or both mitochondrial and nuclear protein synthesis. When cells are grown in glycerol, the response after dark liquid holding of UV-treated cells in the different growth stages are similar to that found for glucose-grown cells. In other words, the fate of cytoplasmic genetic damage, in particular, is not correlated with the repressed or derepressed state of the mitochondria.

  7. Endogenous Mouse Dicer Is an Exclusively Cytoplasmic Protein.

    Directory of Open Access Journals (Sweden)

    Christian Much

    2016-06-01

    Full Text Available Dicer is a large multi-domain protein responsible for the ultimate step of microRNA and short-interfering RNA biogenesis. In human and mouse cell lines, Dicer has been shown to be important in the nuclear clearance of dsRNA as well as the establishment of chromatin modifications. Here we set out to unambiguously define the cellular localization of Dicer in mice to understand if this is a conserved feature of mammalian Dicer in vivo. To this end, we utilized an endogenously epitope tagged Dicer knock-in mouse allele. From primary mouse cell lines and adult tissues, we determined with certainty by biochemical fractionation and confocal immunofluorescence microscopy that endogenous Dicer is exclusively cytoplasmic. We ruled out the possibility that a fraction of Dicer shuttles to and from the nucleus as well as that FGF or DNA damage signaling induce Dicer nuclear translocation. We also explored Dicer localization during the dynamic and developmental context of embryogenesis, where Dicer is ubiquitously expressed and strictly cytoplasmic in all three germ layers as well as extraembryonic tissues. Our data exclude a direct role for Dicer in the nuclear RNA processing in the mouse.

  8. Endogenous Mouse Dicer Is an Exclusively Cytoplasmic Protein.

    Science.gov (United States)

    Much, Christian; Auchynnikava, Tania; Pavlinic, Dinko; Buness, Andreas; Rappsilber, Juri; Benes, Vladimir; Allshire, Robin; O'Carroll, Dónal

    2016-06-01

    Dicer is a large multi-domain protein responsible for the ultimate step of microRNA and short-interfering RNA biogenesis. In human and mouse cell lines, Dicer has been shown to be important in the nuclear clearance of dsRNA as well as the establishment of chromatin modifications. Here we set out to unambiguously define the cellular localization of Dicer in mice to understand if this is a conserved feature of mammalian Dicer in vivo. To this end, we utilized an endogenously epitope tagged Dicer knock-in mouse allele. From primary mouse cell lines and adult tissues, we determined with certainty by biochemical fractionation and confocal immunofluorescence microscopy that endogenous Dicer is exclusively cytoplasmic. We ruled out the possibility that a fraction of Dicer shuttles to and from the nucleus as well as that FGF or DNA damage signaling induce Dicer nuclear translocation. We also explored Dicer localization during the dynamic and developmental context of embryogenesis, where Dicer is ubiquitously expressed and strictly cytoplasmic in all three germ layers as well as extraembryonic tissues. Our data exclude a direct role for Dicer in the nuclear RNA processing in the mouse.

  9. Algorithms for Cytoplasm Segmentation of Fluorescence Labelled Cells

    Directory of Open Access Journals (Sweden)

    Carolina Wählby

    2002-01-01

    Full Text Available Automatic cell segmentation has various applications in cytometry, and while the nucleus is often very distinct and easy to identify, the cytoplasm provides a lot more challenge. A new combination of image analysis algorithms for segmentation of cells imaged by fluorescence microscopy is presented. The algorithm consists of an image pre‐processing step, a general segmentation and merging step followed by a segmentation quality measurement. The quality measurement consists of a statistical analysis of a number of shape descriptive features. Objects that have features that differ to that of correctly segmented single cells can be further processed by a splitting step. By statistical analysis we therefore get a feedback system for separation of clustered cells. After the segmentation is completed, the quality of the final segmentation is evaluated. By training the algorithm on a representative set of training images, the algorithm is made fully automatic for subsequent images created under similar conditions. Automatic cytoplasm segmentation was tested on CHO‐cells stained with calcein. The fully automatic method showed between 89% and 97% correct segmentation as compared to manual segmentation.

  10. iTRAQ-Based Proteomics Analyses of Sterile/Fertile Anthers from a Thermo-Sensitive Cytoplasmic Male-Sterile Wheat with Aegilops kotschyi Cytoplasm

    Directory of Open Access Journals (Sweden)

    Gaoming Zhang

    2018-05-01

    Full Text Available A “two-line hybrid system” was developed, previously based on thermo-sensitive cytoplasmic male sterility in Aegilops kotschyi (K-TCMS, which can be used in wheat breeding. The K-TCMS line exhibits complete male sterility and it can be used to produce hybrid wheat seeds during the normal wheat-growing season; it propagates via self-pollination at high temperatures. Isobaric tags for relative and absolute quantification-based quantitative proteome and bioinformatics analyses of the TCMS line KTM3315A were conducted under different fertility conditions to understand the mechanisms of fertility conversion in the pollen development stages. In total, 4639 proteins were identified, the differentially abundant proteins that increased/decreased in plants with differences in fertility were mainly involved with energy metabolism, starch and sucrose metabolism, phenylpropanoid biosynthesis, protein synthesis, translation, folding, and degradation. Compared with the sterile condition, many of the proteins that related to energy and phenylpropanoid metabolism increased during the anther development stage. Thus, we suggest that energy and phenylpropanoid metabolism pathways are important for fertility conversion in K-TCMS wheat. These findings provide valuable insights into the proteins involved with anther and pollen development, thereby, helping to further understand the mechanism of TCMS in wheat.

  11. Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments.

    Science.gov (United States)

    Patheja, Pooja; Sahu, Khageswar

    2017-06-15

    Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MɸCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MɸCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. In vivo effect of interleukin-1beta and interleukin-1RA on oocyte cytoplasmic maturation, ovulation, and early embryonic development in the mare

    Directory of Open Access Journals (Sweden)

    Gérard Nadine

    2005-06-01

    Full Text Available Abstract A growing body of evidence suggests that the interleukin-1 system is involved in periovulatory events. Previous work from our lab demonstrated that in the mare, interleukin-1beta (IL-1beta increases the ovulatory rate of metaphase II oocytes. The present study was conducted to analyze in vivo the effect of IL-1 on oocyte cytoplasmic maturation, ovulation and pregnancy rate. In the present work, IL-1beta (experiment 1, n = 13; experiment 2, n = 25 and interleukin-1RA (IL-1RA; experiment 1, n = 25 were injected intrafollicularly by using the transvaginal ultrasound-guided injection method. Injections were performed on cyclic mares when the diameter of the growing dominant follicle reached 30–34 mm. In experiment 1, mares were inseminated the day of the treatment and all the other day until ovulation. The time of ovulation was determined and a pregnancy diagnosis was performed 14 days after ovulation of the injected follicle. In experiment 2, the cumulus-oocyte complex from each injected follicle was collected by transvaginal ultrasound-guided aspiration 38 h after the intrafollicular injection. Oocyte nuclear stage and oocyte cytoplasmic maturation were assessed by analyzing chromatin configuration, cortical granules migration and mitochondria distribution under a confocal microscope. The results from experiment 1 confirm that an intrafollicular injection of 1 microgram IL-1beta induces ovulation in the mare whereas IL-1RA has no effect at the dose used in the present study. Furthemore, we demonstrated, that in our experimental conditions, IL-1beta and IL-1RA induced a decrease in embryo development. Experiment 2 leads us to observe that IL-1beta is unable to induce cortical granules migration and remodelling of mitochondria, that commonly occurs during oocyte maturation, whereas it acts on nuclear maturation. This result may explain the decrease in embryo development we observed after IL-1beta intrafollicular injection. In conclusion

  13. Analysis of embryo, cytoplasmic and maternal genetic correlations ...

    Indian Academy of Sciences (India)

    rapeseed meal have been applied to high-valued animal feed ingredients. Several results have confirmed that plant protein is more beneficial to humans than animal protein (Friedman ...... plant proteins of diets for non-ruminants. In Recent ...

  14. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  15. Propylthiouracil-Induced Vasculitis With Antineutrophil Cytoplasmic Antibody.

    Science.gov (United States)

    Criado, Paulo Ricardo; Grizzo Peres Martins, Ana Claudia; Gaviolli, Camila Fatima; Alavi, Afsaneh

    2015-06-01

    Propylthiouracil (PTU)-associated vasculitis is a potentially life-threatening disease with a recent increase in the reported cases in the medical literature. This increase may suggest that some earlier cases have been unrecognized or assigned to an alternative nosology category. Although the skin can be the only organ affected by PTU-associated vasculitis, there are many reports with multiple-system involvement. Classically, the symptoms appear under a tetrad of fever, sore throat, arthralgia, and skin lesions. Cutaneous lesions in reported cases of PTU vasculitis have most commonly consisted of retiform acral, purpuric plaques, or nodules. We report a case of perinuclear antineutrophil cytoplasmic antibody-associated vasculitis developed during treatment with PTU for Grave's disease. © The Author(s) 2014.

  16. Investigation of radiation enhanced reactivation of cytoplasmic replicating human virus

    International Nuclear Information System (INIS)

    Bockstahler, L.E.; Haynes, K.F.; Stafford, J.E.

    1976-01-01

    When monolayers of CV-1 monkey kidney cells were exposed to ultraviolet (uv) radiation (0 to 200 erg/nm 2 ) or x rays (0 to 10 krads) before infection with uv-irradiated herpes simplex virus, an increase in the infectivity of this nuclear replicating virus occurred as measured by plaque formation. These phenomena are known as uv (Weigle) reactivation (WR) and x-ray reactivation (x-ray R). In this study the presence of WR and x-ray R was examined in CV-1 cells infected with uv-irradiated vaccinia virus or poliovirus, both cytoplasmic replicating viruses. Little or no WR or x-ray R was observed for either of these viruses. These results suggest that WR and x-ray R in mammalian cells may be restricted to viruses which are synthesized in the cell nucleus

  17. [Antineutrophil cytoplasmic antibodies associated with infective endocarditis: Literature review].

    Science.gov (United States)

    Langlois, V; Marie, I

    2017-07-01

    Antineutrophil cytoplasmic antibodies (ANCA) associated with infective endocarditis are a rare disorder. The condition can mimic primary systemic vasculitis (i.e. granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis). Thus, a wrong diagnosis of valvular involvement related to primary systemic vasculitis can be made in patients exhibiting ANCA associated with infective endocarditis. Because treatment of both conditions is different, this wrong diagnosis will lead to dramatic consequences in these latter patients. This review reports the state of knowledge and proposes an algorithm to follow when confronted to a possible case of ANCA associated with infective endocarditis. Copyright © 2016 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  18. Structural Basis for Redox Regulation of Cytoplasmic and Chloroplastic Triosephosphate Isomerases from Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Laura Margarita López-Castillo

    2016-12-01

    Full Text Available In plants triosephosphate isomerase (TPI interconverts glyceraldehyde 3-phosphate (G3P and dihydroxyacetone phosphate (DHAP during glycolysis, gluconeogenesis, and the Calvin-Benson cycle. The nuclear genome of land plants encodes two tpi genes, one gene product is located in the cytoplasm and the other is imported into the chloroplast. Herein we report the crystal structures of the TPIs from the vascular plant Arabidopsis thaliana (AtTPIs and address their enzymatic modulation by redox agents. Cytoplasmic TPI (cTPI and chloroplast TPI (pdTPI share more than 60% amino acid identity and assemble as (β-α8 dimers with high structural homology. cTPI and pdTPI harbor two and one accessible thiol groups per monomer respectively. cTPI and pdTPI present a cysteine at an equivalent structural position (C13 and C15 respectively and cTPI also contains a specific solvent accessible cysteine at residue 218 (cTPI-C218. Site directed mutagenesis of residues pdTPI-C15, cTPI-C13 and cTPI-C218 to serine substantially decreases enzymatic activity, indicating that the structural integrity of these cysteines is necessary for catalysis. AtTPIs exhibit differential responses to oxidative agents, cTPI is susceptible to oxidative agents such as diamide and H2O2, whereas pdTPI is resistant to inhibition. Incubation of AtTPIs with the sulfhydryl conjugating reagents methylmethane thiosulfonate (MMTS and glutathione inhibits enzymatic activity. However, the concentration necessary to inhibit pdTPI is at least two orders of magnitude higher than the concentration needed to inhibit cTPI. Western-blot analysis indicates that residues cTPI-C13, cTPI-C218, and pdTPI-C15 conjugate with glutathione. In summary, our data indicate that AtTPIs could be redox regulated by the derivatization of specific AtTPI cysteines (cTPI-C13 and pdTPI-C15 and cTPI-C218. Since AtTPIs have evolved by gene duplication, the higher resistance of pdTPI to redox agents may be an adaptive consequence to

  19. 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....

  20. Appearance of newly formed mRNA and rRNA as ribonucleoprotein-particles in the cytoplasmic subribosomal fraction of pea embryos

    International Nuclear Information System (INIS)

    Takahashi, Noribumi; Takaiwa, Fumio; Fukuei, Keisuke; Sakamaki, Tadashi; Tanifuji, Shigeyuki

    1977-01-01

    Incorporation studies with 3 H-uridine or 3 H-adenosine showed that germinating pea embryos synthesize all types of poly A(+) RNA, rRNA and 4-5S RNA at the early stage of germination. After the pulse labeling for 30 min, only heterodisperse RNA and 4-5S RNA appeared in the cytoplasm as labeled RNA species. At this time the radioactivity was associated with cytoplasmic structures heavier than 80S and RNP particles of 68-70S, 52-55S, 36-38S and 20-22S which are presumed to be free mRNP particles in plants. When the pulse-labeled embryos were incubated for a further 60 min in an isotope-free medium, the labeled 17S and 25S rRNA emerged in the cytoplasm, together with labeled heterodisperse and 4-5S RNAs. More radioactivity accumulated in the regions of the polysome, 62-65S and 38-42S particles. The results of analysis of RNAs extracted from the whole cytoplasm, polysome or subribosomal fractions indicated that small subunits of newly formed ribosomes appear more rapidly in the cytoplasm than new large subunits, which accumulate for a while as free particles in the cytoplasm than are incorporated into polysomes. The actinomycin treatment which caused preferential inhibition of rRNA synthesis reduced the accumulation of free, newly formed ribosome subunits and partially permitted detection of the presumed mRNP particles in the subribosomal region even after the chase treatment. (auth.)

  1. A complete mitochondrial genome sequence of Ogura-type male-sterile cytoplasm and its comparative analysis with that of normal cytoplasm in radish (Raphanus sativus L.

    Directory of Open Access Journals (Sweden)

    Tanaka Yoshiyuki

    2012-07-01

    Full Text Available Abstract Background Plant mitochondrial genome has unique features such as large size, frequent recombination and incorporation of foreign DNA. Cytoplasmic male sterility (CMS is caused by rearrangement of the mitochondrial genome, and a novel chimeric open reading frame (ORF created by shuffling of endogenous sequences is often responsible for CMS. The Ogura-type male-sterile cytoplasm is one of the most extensively studied cytoplasms in Brassicaceae. Although the gene orf138 has been isolated as a determinant of Ogura-type CMS, no homologous sequence to orf138 has been found in public databases. Therefore, how orf138 sequence was created is a mystery. In this study, we determined the complete nucleotide sequence of two radish mitochondrial genomes, namely, Ogura- and normal-type genomes, and analyzed them to reveal the origin of the gene orf138. Results Ogura- and normal-type mitochondrial genomes were assembled to 258,426-bp and 244,036-bp circular sequences, respectively. Normal-type mitochondrial genome contained 33 protein-coding and three rRNA genes, which are well conserved with the reported mitochondrial genome of rapeseed. Ogura-type genomes contained same genes and additional atp9. As for tRNA, normal-type contained 17 tRNAs, while Ogura-type contained 17 tRNAs and one additional trnfM. The gene orf138 was specific to Ogura-type mitochondrial genome, and no sequence homologous to it was found in normal-type genome. Comparative analysis of the two genomes revealed that radish mitochondrial genome consists of 11 syntenic regions (length >3 kb, similarity >99.9%. It was shown that short repeats and overlapped repeats present in the edge of syntenic regions were involved in recombination events during evolution to interconvert two types of mitochondrial genome. Ogura-type mitochondrial genome has four unique regions (2,803 bp, 1,601 bp, 451 bp and 15,255 bp in size that are non-syntenic to normal-type genome, and the gene orf138

  2. CORSEN, a new software dedicated to microscope-based 3D distance measurements: mRNA-mitochondria distance, from single-cell to population analyses.

    Science.gov (United States)

    Jourdren, Laurent; Delaveau, Thierry; Marquenet, Emelie; Jacq, Claude; Garcia, Mathilde

    2010-07-01

    Recent improvements in microscopy technology allow detection of single molecules of RNA, but tools for large-scale automatic analyses of particle distributions are lacking. An increasing number of imaging studies emphasize the importance of mRNA localization in the definition of cell territory or the biogenesis of cell compartments. CORSEN is a new tool dedicated to three-dimensional (3D) distance measurements from imaging experiments especially developed to access the minimal distance between RNA molecules and cellular compartment markers. CORSEN includes a 3D segmentation algorithm allowing the extraction and the characterization of the cellular objects to be processed--surface determination, aggregate decomposition--for minimal distance calculations. CORSEN's main contribution lies in exploratory statistical analysis, cell population characterization, and high-throughput assays that are made possible by the implementation of a batch process analysis. We highlighted CORSEN's utility for the study of relative positions of mRNA molecules and mitochondria: CORSEN clearly discriminates mRNA localized to the vicinity of mitochondria from those that are translated on free cytoplasmic polysomes. Moreover, it quantifies the cell-to-cell variations of mRNA localization and emphasizes the necessity for statistical approaches. This method can be extended to assess the evolution of the distance between specific mRNAs and other cellular structures in different cellular contexts. CORSEN was designed for the biologist community with the concern to provide an easy-to-use and highly flexible tool that can be applied for diverse distance quantification issues.

  3. Cytoplasmic Nucleation and Atypical Branching Nucleation Generate Endoplasmic Microtubules in Physcomitrella patens[OPEN

    Science.gov (United States)

    Nakaoka, Yuki; Kimura, Akatsuki; Tani, Tomomi; Goshima, Gohta

    2015-01-01

    The mechanism underlying microtubule (MT) generation in plants has been primarily studied using the cortical MT array, in which fixed-angled branching nucleation and katanin-dependent MT severing predominate. However, little is known about MT generation in the endoplasm. Here, we explored the mechanism of endoplasmic MT generation in protonemal cells of Physcomitrella patens. We developed an assay that utilizes flow cell and oblique illumination fluorescence microscopy, which allowed visualization and quantification of individual MT dynamics. MT severing was infrequently observed, and disruption of katanin did not severely affect MT generation. Branching nucleation was observed, but it showed markedly variable branch angles and was occasionally accompanied by the transport of nucleated MTs. Cytoplasmic nucleation at seemingly random locations was most frequently observed and predominated when depolymerized MTs were regrown. The MT nucleator γ-tubulin was detected at the majority of the nucleation sites, at which a single MT was generated in random directions. When γ-tubulin was knocked down, MT generation was significantly delayed in the regrowth assay. However, nucleation occurred at a normal frequency in steady state, suggesting the presence of a γ-tubulin-independent backup mechanism. Thus, endoplasmic MTs in this cell type are generated in a less ordered manner, showing a broader spectrum of nucleation mechanisms in plants. PMID:25616870

  4. Molecular Characterization of Bombyx mori Cytoplasmic Polyhedrosis Virus Genome Segment 4

    Science.gov (United States)

    Ikeda, Keiko; Nagaoka, Sumiharu; Winkler, Stefan; Kotani, Kumiko; Yagi, Hiroaki; Nakanishi, Kae; Miyajima, Shigetoshi; Kobayashi, Jun; Mori, Hajime

    2001-01-01

    The complete nucleotide sequence of the genome segment 4 (S4) of Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) was determined. The 3,259-nucleotide sequence contains a single long open reading frame which spans nucleotides 14 to 3187 and which is predicted to encode a protein with a molecular mass of about 130 kDa. Western blot analysis showed that S4 encodes BmCPV protein VP3, which is one of the outer components of the BmCPV virion. Sequence analysis of the deduced amino acid sequence of BmCPV VP3 revealed possible sequence homology with proteins from rice ragged stunt virus (RRSV) S2, Nilaparvata lugens reovirus S4, and Fiji disease fijivirus S4. This may suggest that plant reoviruses originated from insect viruses and that RRSV emerged more recently than other plant reoviruses. A chimeric protein consisting of BmCPV VP3 and green fluorescent protein (GFP) was constructed and expressed with BmCPV polyhedrin using a baculovirus expression vector. The VP3-GFP chimera was incorporated into BmCPV polyhedra and released under alkaline conditions. The results indicate that specific interactions occur between BmCPV polyhedrin and VP3 which might facilitate BmCPV virion occlusion into the polyhedra. PMID:11134312

  5. Phosphorylation of the dimeric cytoplasmic domain of the phytosulfokine receptor, PSKR1

    KAUST Repository

    Muleya, V.; Marondedze, Claudius; Wheeler, J. I.; Thomas, Ludivine; Mok, Y.-F.; Griffin, M. D. W.; Manallack, D. T.; Kwezi, L.; Lilley, K. S.; Gehring, Christoph A; Irving, H. R.

    2016-01-01

    Phytosulfokines (PSKs) are plant peptide hormones that co-regulate plant growth, differentiation and defense responses. PSKs signal through a plasma membrane localized leucine-rich repeat receptor-like kinase (phytosulfokine receptor 1, PSKR1) that also contains a functional cytosolic guanylate cyclase with its cyclase catalytic center embedded within the kinase domain. To functionally characterize this novel type of overlapping dual catalytic function, we investigated the phosphorylation of PSKR1 in vitro Tandem mass spectrometry of the cytoplasmic domain of PSKR1 (PSKR1cd) revealed at least 11 phosphorylation sites (8 serines, 2 threonines and 1 tyrosine) within the PSKR1cd. Phosphomimetic mutations of three serine residues (Ser686, Ser696 and Ser698) in tandem at the juxta-membrane position resulted in enhanced kinase activity in the on-mutant that was suppressed in the off-mutant, but both mutations reduced guanylate cyclase activity. Both the on and off phosphomimetic mutations of the phosphotyrosine (Tyr888) residue in the activation loop suppressed kinase activity, while neither mutation affected guanylate cyclase activity. Size exclusion and analytical ultracentrifugation analysis of the PSKR1cd suggest that it is reversibly dimeric in solution, which was further confirmed by biflourescence complementation. Taken together, these data suggest that in this novel type of receptor domain architecture, specific phosphorylation and dimerization are possibly essential mechanisms for ligand-mediated catalysis and signaling.

  6. Phosphorylation of the dimeric cytoplasmic domain of the phytosulfokine receptor, PSKR1

    KAUST Repository

    Muleya, V.

    2016-08-04

    Phytosulfokines (PSKs) are plant peptide hormones that co-regulate plant growth, differentiation and defense responses. PSKs signal through a plasma membrane localized leucine-rich repeat receptor-like kinase (phytosulfokine receptor 1, PSKR1) that also contains a functional cytosolic guanylate cyclase with its cyclase catalytic center embedded within the kinase domain. To functionally characterize this novel type of overlapping dual catalytic function, we investigated the phosphorylation of PSKR1 in vitro Tandem mass spectrometry of the cytoplasmic domain of PSKR1 (PSKR1cd) revealed at least 11 phosphorylation sites (8 serines, 2 threonines and 1 tyrosine) within the PSKR1cd. Phosphomimetic mutations of three serine residues (Ser686, Ser696 and Ser698) in tandem at the juxta-membrane position resulted in enhanced kinase activity in the on-mutant that was suppressed in the off-mutant, but both mutations reduced guanylate cyclase activity. Both the on and off phosphomimetic mutations of the phosphotyrosine (Tyr888) residue in the activation loop suppressed kinase activity, while neither mutation affected guanylate cyclase activity. Size exclusion and analytical ultracentrifugation analysis of the PSKR1cd suggest that it is reversibly dimeric in solution, which was further confirmed by biflourescence complementation. Taken together, these data suggest that in this novel type of receptor domain architecture, specific phosphorylation and dimerization are possibly essential mechanisms for ligand-mediated catalysis and signaling.

  7. Agronomic Performance of Flue-Cured Tobacco F1 Hybrids Obtained with Different Sources of Male Sterile Cytoplasm

    Directory of Open Access Journals (Sweden)

    Berbec A

    2014-12-01

    Full Text Available Four cytoplasmic male sterile (cms F1flue-cured hybrids cv. Wiaelica × cv. Virginia Golta (VG, the male fertile analogue and the parental varieties were tested at two locations in Poland in a replicated field trial. The cms sources in the hybrids wereN. suaveolens,N. amplexicaulis,N. bigeloviiand aN. tabacumcms mutant. Under the slight to moderate pressure from black root rot present at the trial sites the hybrids showed a moderate tolerance of the disease characteristic of VG as opposed to medium strong susceptibility of Wislica. Apart from the effect of black root rot tolerance the vegetative vigor of the hybrids (plant height, leaf size, earliness was affected by cytoplasm source. The F1hybrid withN. suaveolens cytoplasm flowered approximately three days later than the remaining hybrids. Of the cms hybrids tested cmsN. bigelovii produced the tallest plants with largest mid-position leaves. Yields of cured leaves were largely influenced by black root rot and were generally higher in VG and in the hybrids than in Wislica. Leaf yields and curability were generally little affected by cms source under low pressure from black root rot. At the site with a relatively high level of black root rot infestation the yields of cmsN. suaveolens were slightly lower but the percentage of light grades slightly higher compared to those of other cms hybrids. CmsN. suaveolens was the best hybrid in terms of money returns at the low black root rot field but it was the poorest hybrid performer under high pressure from the disease. Contents of nitrogen, sugars, nicotine and ash was little affected by source of cms. There was an increased incidence of potato virus Y (PVY and white spots in cmsN. suaveolens and, to a lesser extent, in cmsN. bigelovii as compared to the remaining disease-free entries.

  8. 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

  9. 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

  10. 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)

  11. 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.

  12. 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.

  13. Water diffusion in cytoplasmic streaming in Elodea internodal cells under the effect of antimitotic agents.

    Science.gov (United States)

    Vorob'ev, Vladimir N; Anisimov, Alexander V; Dautova, Nailya R

    2008-07-01

    The translational displacement of the cytoplasmic water in Elodea stem cells resulting from protein motor activity was measured using the NMR method. A 24-h treatment with vincristine results in a reduction of the translational displacement of the cytoplasmic water. With a constant cytoplasmic streaming velocity, the dynamics of the translational displacement of the cytoplasmic water under the effect of taxol are characterized by a continuous increase at a concentration of 0.05 mM, and reaching a plateau at a concentration of 0.5 mM.

  14. Crystallization and preliminary crystallographic analysis of Arabidopsis thaliana BRI1-associated kinase 1 (BAK1) cytoplasmic domain

    International Nuclear Information System (INIS)

    Gao, Jian; Ma, Yuanyuan; Sun, Yuna; Zhao, Huadong; Hong, Dapeng; Yan, Liming; Lou, Zhiyong

    2012-01-01

    The cytoplasmic domain of BRI1-associated kinase 1 from A. thaliana has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 2.6 Å resolution. BRI1-associated kinase 1 (BAK1) is a member of the plant receptor-like kinase (RLK) superfamily. BAK1 has been shown to initiate brassinosteroid (BR) signalling and innate immune responses in plants by forming receptor complexes with both brassinosteroid-insensitive 1 (BRI1) and flagellin-sensing 2 (FLS2). To gain a better understanding of the structural details and the mechanism of action of the BAK1 kinase domain, recombinant BAK1 cytoplasmic domain has been expressed, purified and crystallized at 291 K using PEG 3350 as a precipitant. A 2.6 Å resolution data set was collected from a single flash-cooled crystal at 100 K. This crystal belonged to space group C2, with unit-cell parameters a = 70.3, b = 75.6, c = 71.9 Å, β = 93.1°. Assuming the presence of one molecule in the asymmetric unit, the Matthews coefficient was 2.6 Å 3 Da −1

  15. Investigations on the mechanism of oxygen-dependent plant processes: ethylene biosynthesis and cyanide-resistant respiration

    International Nuclear Information System (INIS)

    Stegink, S.J.

    1985-01-01

    Two oxygen-dependent plant processes were investigated. A cell-free preparation from pea (Pisum sativum L., cv. Alaska) was used to study ethylene biosynthesis from 1-aminocyclopropane-1-carboxylic acid. Mitochondrial cyanide-resistant respiration was investigated in studies with 14 C-butyl gallate and other respiratory effectors. Ethylene biosynthesis was not due to a specific enzyme, or oxygen radicals. Rather, hydrogen peroxide, generated at low levels, coupled with endogenous manganese produced ethylene. 14 C-butyl gallate bound specifically to mitochondria from cyanide-sensitive and -resistant higher plants and Neurospora crassa mitochondria. The amount of gallate bound was similar for all higher plant mitochondria. Rat liver mitochondria bound very little 14 C-butyl gallate. Plant mitochondria in which cyanide-resistance was induced bound as much 14 C-butyl gallate as before induction. However mitochondria from recently harvested white potato tubers did not bind the gallate. The observations suggest that an engaging factor couples with a gallate binding site in the mitochondrial membrane. With skunk cabbage spadix mitochondria the I 5 0 for antimycin A inhibition of oxygen uptake was decreased by salicylhydroxamic acid pretreatment; this was also true for reverse order additions. No shift was observed with mung bean hypocotyl or Jerusalem artichoke tuber mitochondria

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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)

  4. Cytoplasmic and nuclear DNA markers as powerful tools in ...

    African Journals Online (AJOL)

    Plants are distinguished among eukaryotes in possessing two DNA-containing organelles, the mitochondrion and the plastid, whereas, most eucaryotes contain only the mitochondrial genome. Recently, both organelles are used efficiently in population studies as plant geneticists developed molecular techniques that ...

  5. 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

  6. Effect of expressing an anti-HIV lectin, Griffithsin, in different plant cellular compartments

    CSIR Research Space (South Africa)

    Stark, T

    2010-08-01

    Full Text Available of subcellular targeting of GRFT in tobacco on expression levels and plant cell viability • Integration vector • Deconstructed viral vector © CSIR 2010 Slide 8 Subcellular location Nucleus Nucleolus Endoplasmic reticulum Vacuole Mitochondria Golgi...

  7. Protein carbonylation in plants

    DEFF Research Database (Denmark)

    Møller, Ian Max; Havelund, Jesper; Rogowska-Wrzesinska, Adelina

    2017-01-01

    This chapter provides an overview of the current knowledge on protein carbonylation in plants and its role in plant physiology. It starts with a brief outline of the turnover and production sites of reactive oxygen species (ROS) in plants and the causes of protein carbonylation. This is followed...... by a description of the methods used to study protein carbonylation in plants, which is also very brief as the methods are similar to those used in studies on animals. The chapter also focuses on protein carbonylation in plants in general and in mitochondria and in seeds in particular, as case stories where...... specific carbonylated proteins have been identified. Protein carbonylation appears to accumulate at all stages of seed development and germination investigated to date. In some cases, such as seed aging, it is probably simply an accumulation of oxidative damage. However, in other cases protein...

  8. Anti-neutrophil cytoplasmic antibodies stimulate release of neutrophil microparticles.

    LENUS (Irish Health Repository)

    Hong, Ying

    2012-01-01

    The mechanisms by which anti-neutrophil cytoplasmic antibodies (ANCAs) may contribute to the pathogenesis of ANCA-associated vasculitis are not well understood. In this study, both polyclonal ANCAs isolated from patients and chimeric proteinase 3-ANCA induced the release of neutrophil microparticles from primed neutrophils. These microparticles expressed a variety of markers, including the ANCA autoantigens proteinase 3 and myeloperoxidase. They bound endothelial cells via a CD18-mediated mechanism and induced an increase in endothelial intercellular adhesion molecule-1 expression, production of endothelial reactive oxygen species, and release of endothelial IL-6 and IL-8. Removal of the neutrophil microparticles by filtration or inhibition of reactive oxygen species production with antioxidants abolished microparticle-mediated endothelial activation. In addition, these microparticles promoted the generation of thrombin. In vivo, we detected more neutrophil microparticles in the plasma of children with ANCA-associated vasculitis compared with that in healthy controls or those with inactive vasculitis. Taken together, these results support a role for neutrophil microparticles in the pathogenesis of ANCA-associated vasculitis, potentially providing a target for future therapeutics.

  9. Lessons from Animal Models of Cytoplasmic Intermediate Filament Proteins.

    Science.gov (United States)

    Bouameur, Jamal-Eddine; Magin, Thomas M

    Cytoplasmic intermediate filaments (IFs) represent a major cytoskeletal network contributing to cell shape, adhesion and migration as well as to tissue resilience and renewal in numerous bilaterians, including mammals. The observation that IFs are dispensable in cultured mammalian cells, but cause tissue-specific, life-threatening disorders, has pushed the need to investigate their function in vivo. In keeping with human disease, the deletion or mutation of murine IF genes resulted in highly specific pathologies. Epidermal keratins, together with desmin, are essential to protect corresponding tissues against mechanical force but also participate in stabilizing cell adhesion and in inflammatory signalling. Surprisingly, other IF proteins contribute to tissue integrity to a much lesser extent than anticipated, pointing towards their role in stress situations. In support, the overexpression of small chaperones or the interference with inflammatory signalling in several settings has been shown to rescue severe tissue pathologies that resulted from the expression of mutant IF proteins. It stills remains an open issue whether the wide range of IF disorders share similar pathomechanisms. Moreover, we lack an understanding how IF proteins participate in signalling processes. Now, with a large number of mouse models in hand, the next challenge will be to develop organotypic cell culture models to dissect pathomechanisms at the molecular level, to employ Crispr/Cas-mediated genome engineering to optimize models and, finally, to combine available animal models with medicinal chemistry for the development of molecular therapies.

  10. Sexy sons: a dead end for cytoplasmic genes.

    Science.gov (United States)

    Zeh, Jeanne A

    2004-08-07

    Critics of sexual conflict theory argue that females may gain a net reproductive benefit from mating with manipulative males because the direct costs that they suffer may be offset by the production of sexy, i.e. manipulative, sons. However, this exclusive focus on nuclear gene effects represents an incomplete view of female fitness. Females differ fundamentally from males in transmitting not only nuclear genes but also a wide range of cytoplasmic genetic elements (CGEs) that can have profound effects, from male killing to influencing development of the nervous system and cognitive ability. Maternal transmission of CGEs has two major implications for sexual selection. First, the evolution of male fitness traits, such as sperm competitive ability, may be constrained because response to selection on mitochondrial genomes can occur only through the female line. Second, CGEs bear the direct costs of male manipulation but gain no indirect benefits when females produce sexy sons. This should result in perpetual antagonistic coevolution between nuclear genes involved in male manipulation and CGEs that promote female resistance to male sexually selected traits. Explicit consideration of the consequences of selection acting on CGEs is therefore necessary for a better understanding of the relationship between sexual selection and sexual conflict.

  11. Nuclear counterparts of the cytoplasmic mitochondrial 12S rRNA gene: a problem of ancient DNA and molecular phylogenies.

    Science.gov (United States)

    van der Kuyl, A C; Kuiken, C L; Dekker, J T; Perizonius, W R; Goudsmit, J

    1995-06-01

    Monkey mummy bones and teeth originating from the North Saqqara Baboon Galleries (Egypt), soft tissue from a mummified baboon in a museum collection, and nineteenth/twentieth-century skin fragments from mangabeys were used for DNA extraction and PCR amplification of part of the mitochondrial 12S rRNA gene. Sequences aligning with the 12S rRNA gene were recovered but were only distantly related to contemporary monkey mitochondrial 12S rRNA sequences. However, many of these sequences were identical or closely related to human nuclear DNA sequences resembling mitochondrial 12S rRNA (isolated from a cell line depleted in mitochondria) and therefore have to be considered contamination. Subsequently in a separate study we were able to recover genuine mitochondrial 12S rRNA sequences from many extant species of nonhuman Old World primates and sequences closely resembling the human nuclear integrations. Analysis of all sequences by the neighbor-joining (NJ) method indicated that mitochondrial DNA sequences and their nuclear counterparts can be divided into two distinct clusters. One cluster contained all temporary cytoplasmic mitochondrial DNA sequences and approximately half of the monkey nuclear mitochondriallike sequences. A second cluster contained most human nuclear sequences and the other half of monkey nuclear sequences with a separate branch leading to human and gorilla mitochondrial and nuclear sequences. Sequences recovered from ancient materials were equally divided between the two clusters. These results constitute a warning for when working with ancient DNA or performing phylogenetic analysis using mitochondrial DNA as a target sequence: Nuclear counterparts of mitochondrial genes may lead to faulty interpretation of results.

  12. Effect of gamma-radiation on functioning of bean hypocotyl mitochondria: lipids and lipid-dependent enzymes of the electron transfer chain (ETC)

    Energy Technology Data Exchange (ETDEWEB)

    Pai, K U; Gaur, B K [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

    1982-05-01

    A brief note presents the results of a study of the effect of ..gamma..-radiation on NADH-cytochrome c-reductase and succinate-cytochrome c-reductase of mitochondria from bean hypocotyl segments. About 2.5 cm long hypocotyl segments of 5-day-old kidney bean plants were exposed to 250 and 500 kR /sup 60/Co ..gamma..-rays at an exposure rate of 10 kR per min., maintaining the segments at 0 - 5/sup 0/C during irradiation. The results suggest that radiation adversely affects phospholipids, thereby lowering the activity of the dependent ETC enzymes in mitochondria. The results also indicate a possible radiation-induced destruction of the lipid moiety of co-enzyme Q/sub 10/.

  13. Alamethicin permeabilizes the plasma membrane and mitochondria but not the tonoplast in tobacco (Nicotiana tabacum L. cv Bright Yellow) suspension cells

    DEFF Research Database (Denmark)

    Matic, S.; Geisler, D.A.; Møller, I.M.

    2005-01-01

    remained intact, as indicated by an unaffected tonoplast proton gradient. Low-flux permeabilization of plasma membranes and mitochondria at moderate AlaM concentrations was reversible and did not affect cell vigour. Higher AlaM concentrations induced cell death. After the addition of catalase that removes...... concentrations. Possible uses and limitations of this method for plant cell research are discussed.......The ion channel-forming peptide AlaM (alamethicin) is known to permeabilize isolated mitochondria as well as animal cells. When intact tobacco (Nicotiana tabacum L.) Bright Yellow-2 cells were treated with AlaM, the cells became permeable for low-molecular-mass molecules as shown by induced leakage...

  14. Floral Nectary Anatomy and Ultrastructure in Mycoheterotrophic Plant, Epipogium aphyllum Sw. (Orchidaceae

    Directory of Open Access Journals (Sweden)

    Emilia Święczkowska

    2015-01-01

    Full Text Available Epipogium aphyllum is a European-Asian obligatory mycoheterotrophic orchid containing no chlorophyll. Flowers are not resupinate with a sack-shape spur and cordate lip, which is divided into two parts: the basal (hypochile and distal one (epichile. The floral analysis provides strong evidence to conclude that nectar is secreted on the upper surface of pink-coloured papillate ridges and epidermal (adaxial cells at different place in spur, especially at the apex. The exudation on papillae has been observed through the entire anthesis and it has been stained on polysaccharides, proteins, and lipids. The dense cytoplasm of papillae contains profuse endoplasmic reticulum, plentiful vesicles (bigger ones with tannin-like materials, numerous mitochondria, sometimes dictyosomes, starch grains, and plastids with tubular structures. The large electron-dense bodies in cell walls are structurally the same as tannin-like materials from vesicles that are in contact with plasmalemma. The rupture of thin layer of swelled cuticle is caused by pressure of gathered substances exuded due to granulocrine secretion. The idioblasts with raphides occur mainly in tepals tissue. The dynamic changes of the nectar exudation, released through endocrine secretion, have been noticeable during the anthesis: both on the lip and inside the spur. The nectar secretion is not dependent on the colour form of E. aphyllum blooming shoots. The floral biology and ultrastructure differ from mycoheterotrophic plants known up to date.

  15. TRIM5α association with cytoplasmic bodies is not required for antiretroviral activity

    International Nuclear Information System (INIS)

    Song, Byeongwoon; Diaz-Griffero, Felipe; Park, Do Hyun; Rogers, Thomas; Stremlau, Matthew; Sodroski, Joseph

    2005-01-01

    The tripartite motif (TRIM) protein, TRIM5α, restricts infection by particular retroviruses. Many TRIM proteins form cytoplasmic bodies of unknown function. We investigated the relationship between cytoplasmic body formation and the structure and antiretroviral activity of TRIM5α. In addition to diffuse cytoplasmic staining, the TRIM5α proteins from several primate species were located in cytoplasmic bodies of different sizes; by contrast, TRIM5α from spider monkeys did not form cytoplasmic bodies. Despite these differences, all of the TRIM5α proteins exhibited the ability to restrict infection by particular retroviruses. Treatment of cells with geldanamycin, an Hsp90 inhibitor, resulted in disappearance or reduction of the TRIM5α-associated cytoplasmic bodies, yet exerted little effect on the restriction of retroviral infection. Studies of green fluorescent protein-TRIM5α fusion proteins indicated that no TRIM5α domain is specifically required for association with cytoplasmic bodies. Apparently, the formation of cytoplasmic bodies is not required for the antiretroviral activity of TRIM5α

  16. High viscosity and anisotropy characterize the cytoplasm of fungal dormant stress resistant spores

    NARCIS (Netherlands)

    Dijksterhuis, J.; Nijsse, J.; Hoekstra, F.A.; Golovina, E.A.

    2007-01-01

    Ascospores of the fungus Talaromyces macrosporus are dormant and extremely stress resistant, whereas fungal conidia¿the main airborne vehicles of distribution¿are not. Here, physical parameters of the cytoplasm of these types of spores were compared. Cytoplasmic viscosity and level of anisotropy as

  17. Effect of wild Helianthus cytoplasms on agronomic and oil characteristics of cultivated sunflower (H. annuus L.)

    Science.gov (United States)

    Sunflower (Helianthus annuus L.) productions reliance on a single source of cytoplasmic male-sterility, PET1, derived from H. petiolaris Nutt., makes the crop genetically vulnerable. Twenty diverse cytoplasmic substitution lines from annual and perennial wild species were compared with the inbred li...

  18. 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...

  19. 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...

  20. 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.

  1. 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

  2. ING1 induces apoptosis through direct effects at the mitochondria

    DEFF Research Database (Denmark)

    Bose, P; Thakur, S; Thalappilly, S

    2013-01-01

    The ING family of tumor suppressors acts as readers and writers of the histone epigenetic code, affecting DNA repair, chromatin remodeling, cellular senescence, cell cycle regulation and apoptosis. The best characterized member of the ING family, ING1,interacts with the proliferating cell nuclear....... Bioinformatic analysis of the yeast interactome indicates that yeast ING proteins interact with 64 mitochondrial proteins. Also, sequence analysis of ING1 reveals the presence of a BH3-like domain. These data suggest a model in which stress-induced cytoplasmic relocalization of ING1 by14-3-3 induces ING1-BAX...

  3. 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.

  4. 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.)

  5. 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.)

  6. 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.

  7. 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.

  8. 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.

  9. The effects of methylglyoxal-bis(guanylhydrazone) on spermine binding and transport in liver mitochondria.

    Science.gov (United States)

    Toninello, A; Via, L D; Di Noto, V; Mancon, M

    1999-12-15

    This study evaluated the effect of the anticancer drug methylglyoxal-bis(guanylhydrazone) (MGBG) on the binding of the polyamine spermine to the mitochondrial membrane and its transport into the inner compartment of this organelle. Spermine binding was studied by applying a new thermodynamic treatment of ligand-receptor interactions (Di Noto et al., Macromol Theory Simul 5: 165-181, 1996). Results showed that MGBG inhibited the binding of spermine to the site competent for the first step in polyamine transport; the interaction of spermine with this site, termed S1, also mediates the inhibitory effect of the polyamine on the mitochondrial permeability transition (Dalla Via et al., Biochim Biophys Acta 1284: 247-252, 1996). In the presence of 1 mM MGBG, the binding capacity and affinity of this site were reduced by about 2.6-fold; on the contrary, the binding capacity of the S2 site, which is most likely responsible for the internalization of cytoplasmic proteins (see Dalla Via et al., reference cited above), increased by about 1.3-fold, and its binding affinity remained unaffected. MGBG also inhibited the initial rate of spermine transport in a dose-dependent manner by establishing apparently sigmoidal kinetics. Consequently, the total extent of spermine accumulation inside mitochondria was inhibited. This inhibition in transport seems to reflect a conformational change at the level of the channel protein constituting the polyamine transport system, rather than competitive inhibition at the inner active site of the channel, thereby excluding the possibility that the polyamine and drug use the same transport pathway. Furthermore, it is suggested that, in the presence of MGBG, the S2 site is able to participate in residual spermine transport. MGBG also strongly inhibits deltapH-dependent spermine efflux, resulting in a complete block in the bidirectional flux of the polyamine and its sequestration inside the matrix space. The effects of MGBG on spermine accumulation

  10. 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....

  11. Cytoplasmic p21 is a potential predictor for cisplatin sensitivity in ovarian cancer

    International Nuclear Information System (INIS)

    Xia, Xi; Weng, Yanjie; Liao, Shujie; Han, Zhiqiang; Liu, Ronghua; Zhu, Tao; Wang, Shixuan; Xu, Gang; Meng, Li; Zhou, Jianfeng; Ma, Ding; Ma, Quanfu; Li, Xiao; Ji, Teng; Chen, Pingbo; Xu, Hongbin; Li, Kezhen; Fang, Yong; Weng, Danhui

    2011-01-01

    P21 (WAF1/Cip1) binds to cyclin-dependent kinase complexes and inhibits their activities. It was originally described as an inhibitor of cancer cell proliferation. However, many recent studies have shown that p21 promotes tumor progression when accumulated in the cell cytoplasm. So far, little is known about the correlation between cytoplasmic p21 and drug resistance. This study was aimed to investigate the role of p21 in the cisplatin resistance of ovarian cancer. RT-PCR, western blot and immunofluorescence were used to detect p21 expression and location in cisplatin-resistant ovarian cancer cell line C13* and its parental line OV2008. Regulation of cytoplasmic p21 was performed through transfection of p21 siRNA, Akt2 shRNA and Akt2 constitutively active vector in the two cell lines; their effects on cisplatin-induced apoptosis were evaluated by flow cytometry. Tumor tissue sections of clinical samples were analyzed by immunohistochemistry. p21 predominantly localizes to the cytoplasm in C13* compared to OV2008. Persistent exposure to low dose cisplatin in OV2008 leads to p21 translocation from nuclear to cytoplasm, while it had not impact on p21 localization in C13*. Knockdown of cytoplasmic p21 by p21 siRNA transfection in C13* notably increased cisplatin-induced apoptosis through activation of caspase 3. Inhibition of p21 translocation into the cytoplasm by transfection of Akt2 shRNA into C13* cells significantly increased cisplatin-induced apoptosis, while induction of p21 translocation into the cytoplasm by transfection of constitutively active Akt2 in OV2008 enhanced the resistance to cisplatin. Immunohistochemical analysis of clinical ovarian tumor tissues demonstrated that cytoplasmic p21 was negatively correlated with the response to cisplatin based treatment. Cytoplasmic p21 is a novel biomarker of cisplatin resistance and it may represent a potential therapeutic target for ovarian tumors that are refractory to conventional treatment

  12. Functional Marker Assisted Improvement of Stable Cytoplasmic Male Sterile Lines of Rice for Bacterial Blight Resistance

    Directory of Open Access Journals (Sweden)

    Jegadeesan Ramalingam

    2017-06-01

    Full Text Available Bacterial blight (BB, caused by Xanthomonas oryzae pv.oryzae is one among the major diseases in rice, which in severe condition cause losses up to 60% in total yield. Marker assisted pyramiding of three broad spectrum BB resistance genes (xa5, xa13, and Xa21 in prominent rice varieties is the most economical and effective strategy for the management of the BB disease. We report here the pyramiding of three genes (xa5, xa13, and Xa21 in maintainer lines (CO 2B, CO 23B, and CO 24B of three promising wild abortive cytoplasmic male sterile lines (CO 2A, CO 23A, and CO 24A through functional markers assisted back cross breeding. IRBB60 with xa5, xa13, and Xa21 genes is used as a donor parent. BC2F1 and BC2F2 generations from a cross of CO 2B, CO 23B, and CO 24B with IRBB60 were evaluated for bacterial blight and non-fertility restoration. In BC2F1, plants with all three resistance genes (xa5, xa13, and Xa21 and high parent genome recovery was identified. In BC2F2, plants with all resistance genes and without fertility restorer (Rf3 and Rf4 were selected. Based on agronomic traits, BB resistance and maintenance of sterility, two plants each in CO 2B × IRBB60, CO 24B × IRBB60 and one plant in CO 23B × IRBB60 combinations were identified. The identified lines were crossed with respective male sterile lines for conversion of improved B line into CMS line through back-crossing, in addition to selfing. The plants with high recurrent genome and phenotypically similar to parental lines and sterile are being used for the hybrid rice development program. Currently, using these lines (improved CMS line, test crosses were made to develop new rice hybrids. Hybrids combinations viz., CO 23A × AD08009R and CO 24A × IET20898R were found to be stable at different locations with high yield. The R line used in this study has been introgressed with xa5, xa13, and Xa21 genes in a separate breeding program. These new hybrids with resistance against bacterial blight

  13. 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.

  14. Architecture and permeability of post-cytokinesis plasmodesmata lacking cytoplasmic sleeves.

    Science.gov (United States)

    Nicolas, William J; Grison, Magali S; Trépout, Sylvain; Gaston, Amélia; Fouché, Mathieu; Cordelières, Fabrice P; Oparka, Karl; Tilsner, Jens; Brocard, Lysiane; Bayer, Emmanuelle M

    2017-06-12

    Plasmodesmata are remarkable cellular machines responsible for the controlled exchange of proteins, small RNAs and signalling molecules between cells. They are lined by the plasma membrane (PM), contain a strand of tubular endoplasmic reticulum (ER), and the space between these two membranes is thought to control plasmodesmata permeability. Here, we have reconstructed plasmodesmata three-dimensional (3D) ultrastructure with an unprecedented level of 3D information using electron tomography. We show that within plasmodesmata, ER-PM contact sites undergo substantial remodelling events during cell differentiation. Instead of being open pores, post-cytokinesis plasmodesmata present such intimate ER-PM contact along the entire length of the pores that no intermembrane gap is visible. Later on, during cell expansion, the plasmodesmata pore widens and the two membranes separate, leaving a cytosolic sleeve spanned by tethers whose presence correlates with the appearance of the intermembrane gap. Surprisingly, the post-cytokinesis plasmodesmata allow diffusion of macromolecules despite the apparent lack of an open cytoplasmic sleeve, forcing the reassessment of the mechanisms that control plant cell-cell communication.

  15. Autophagy in plant pathogenic fungi.

    Science.gov (United States)

    Liu, Xiao-Hong; Xu, Fei; Snyder, John Hugh; Shi, Huan-Bin; Lu, Jian-Ping; Lin, Fu-Cheng

    2016-09-01

    Autophagy is a conserved cellular process that degrades cytoplasmic constituents in vacuoles. Plant pathogenic fungi develop special infection structures and/or secrete a range of enzymes to invade their plant hosts. It has been demonstrated that monitoring autophagy processes can be extremely useful in visualizing the sequence of events leading to pathogenicity of plant pathogenic fungi. In this review, we introduce the molecular mechanisms involved in autophagy. In addition, we explore the relationship between autophagy and pathogenicity in plant pathogenic fungi. Finally, we discuss the various experimental strategies available for use in the study of autophagy in plant pathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 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...

  17. 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.)

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Urinary Biomarkers in Relapsing Antineutrophil Cytoplasmic Antibody-associated Vasculitis

    Science.gov (United States)

    Lieberthal, Jason G.; Cuthbertson, David; Carette, Simon; Hoffman, Gary S.; Khalidi, Nader A.; Koening, Curry L.; Langford, Carol A.; Maksimowicz-McKinnon, Kathleen; Seo, Philip; Specks, Ulrich; Ytterberg, Steven R.; Merkel, Peter A.; Monach, Paul A.

    2015-01-01

    Objective Glomerulonephritis (GN) is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but tools for early detection of renal involvement are imperfect. We investigated 4 urinary proteins as markers of active renal AAV: alpha-1 acid glycoprotein (AGP), kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), and neutrophil gelatinase-associated lipocalin (NGAL). Methods Patients with active renal AAV (n = 20), active nonrenal AAV (n = 16), and AAV in longterm remission (n = 14) were identified within a longitudinal cohort. Urinary biomarker concentrations (by ELISA) were normalized for urine creatinine. Marker levels during active AAV were compared to baseline remission levels (from 1–4 visits) for each patient. Areas under receiver-operating characteristic curves (AUC), sensitivities, specificities, and likelihood ratios (LR) comparing disease states were calculated. Results Baseline biomarker levels varied among patients. All 4 markers increased during renal flares (p < 0.05). MCP-1 discriminated best between active renal disease and remission: a 1.3-fold increase in MCP-1 had 94% sensitivity and 89% specificity for active renal disease (AUC = 0.93, positive LR 8.5, negative LR 0.07). Increased MCP-1 also characterized 50% of apparently nonrenal flares. Change in AGP, KIM-1, or NGAL showed more modest ability to distinguish active renal disease from remission (AUC 0.71–0.75). Hematuria was noted in 83% of active renal episodes, but also 43% of nonrenal flares and 25% of remission samples. Conclusion Either urinary MCP-1 is not specific for GN in AAV, or it identifies early GN not detected by standard assessment and thus has potential to improve care. A followup study with kidney biopsy as the gold standard is needed. PMID:23547217

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  7. Novel CMS lines in pigeonpea [Cajanus cajan (L. Millspaugh] derived from cytoplasmic substitutions, and their effective restoration and deployment in hybrid breeding

    Directory of Open Access Journals (Sweden)

    Abhishek Bohra

    2017-02-01

    Full Text Available The availability of stable cytoplasmic male sterile (CMS or A lines coupled with a robust restoration system (R lines is an essential prerequisite for efficient hybrid breeding. CMS-enabled hybrid technology holds immense potential to enhance the long-stagnant productivity of pigeonpea. In the present investigation, cytoplasmic substitutions were made in the nuclear backgrounds of early-maturing pigeonpea varieties or lines. Three new CMS lines (ICPL 88039A, Pusa 992A, and DPP 3-2A resulted from genetic crosses involving cytoplasmic donors from A2 (GT 288A and A4 (ICPA 2089 categories. In addition to visual inspection of anthers, pollen-staining techniques and scanning electron microscopy (SEM analysis were used to confirm pollen sterility. Further, given the relevance of the plant mitochondrial genome to CMS manifestation, 25 mitochondrion-specific DNA markers were assayed on these newly developed A lines and isogenic maintainer (B lines. DNA polymorphism between Pusa 992A and Pusa 992B as revealed by the nad7a_del marker confirmed the successful combination of sterilizing cytoplasm (A4 and nonrestoring nuclear background (Pusa 992. Such cytoplasm-specific DNA markers are required for A2-CMS as well. Further, to assess restoration ability, potential restorers were crossed with these CMS lines, and as a consequence, promising A × R combinations exhibiting 100% pollen fertility could be identified. In parallel, we also analyzed the inheritance patterns underlying fertility restoration using ICPL 88039A-derived F2 and BC1F1 populations, and established a monogenic dominant model to explain the phenomenon of A2-CMS restoration. In summary, we report the successful development of new CMS lines and describe their effective deployment in hybrid breeding of pigeonpea.

  8. Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV1

    Science.gov (United States)

    Bartoli, Carlos G.; Pastori, Gabriela M.; Foyer, Christine H.

    2000-01-01

    Ascorbic acid is synthesized from galactono-γ-lactone (GL) in plant tissues. An improved extraction procedure involving ammonium sulfate precipitation of membrane proteins from crude leaf homogenates yielded a simple, quick method for determining tissue activities of galactono-γ-lactone dehydrogenase (GLDH). Total foliar ascorbate and GLDH activity decreased with leaf age. Subcellular fractionation experiments using marker enzymes demonstrated that 80% of the total GLDH activity was located on the inner mitochondrial membrane, and 20% in the microsomal fraction. Specific antibody raised against potato (Solanum tuberosum L.) tuber GLDH recognized a 56-kD polypeptide in extracts from the mitochondrial membranes but failed to detect the equivalent polypeptide in microsomes. We demonstrate that isolated intact mitochondria synthesize ascorbate in the presence of GL. GL stimulated mitochondrial electron transport rates. The respiration inhibitor antimycin A stimulated ascorbate biosynthesis, while cyanide inhibited both respiration and ascorbate production. GL-dependent oxygen uptake was observed in isolated intact mitochondria. This evidence suggests that GLDH delivers electrons to the mitochondrial electron transport chain between complexes III and IV. PMID:10806250

  9. Enhanced Autophagy and Reduced Expression of Cathepsin D Are Related to Autophagic Cell Death in Epstein-Barr Virus-Associated Nasal Natural Killer/T-Cell Lymphomas: An Immunohistochemical Analysis of Beclin-1, LC3, Mitochondria (AE-1), and Cathepsin D in Nasopharyngeal Lymphomas

    International Nuclear Information System (INIS)

    Hasui, Kazuhisa; Wang, Jia; Jia, Xinshan; Tanaka, Masashi; Nagai, Taku; Matsuyama, Takami; Eizuru, Yoshito

    2011-01-01

    This study investigated autophagy in 37 cases of nasopharyngeal lymphomas including 23 nasal natural killer (NK)/T-cell lymphomas (NKTCL), 3 cytotoxic T-cell lymphomas (cytotoxic-TML) and 9 B-cell lymphomas (BML) by means of antigen-retrieval immunohistochemistry of beclin-1, LC3, mitochondria (AE-1) and cathepsin D. Peculiar necrosis was noted in EBV + lymphomas comprising 21 NKTCL, 2 cytotoxic-TML and 1 BML. Lymphomas without peculiar necrosis showed high expression of beclin-1, macrogranular cytoplasmal stain of LC3 with sporadic nuclear stain, a hallmark of autophagic cell death (ACD), some aggregated mitochondria and high expression of cathepsin D, suggesting a state of growth with enhanced autophagy with sporadic ACD. EBV + NKTCL with the peculiar necrosis, showed significantly low level of macrogranular staining of LC3, aggregated mitochondria and low expression of cathepsin D in the cellular areas when degenerative lymphoma cells showed decreased beclin-1, significantly advanced LC3-labeled autophagy, residual aggregated mitochondria and significantly reduced expression of cathepsin D, suggesting advanced autophagy with regional ACD. Consequently it was suggested that enhanced autophagy and reduced expression of lysosomal enzymes induced regional ACD under EBV infection in NKTCL

  10. Marker-Assisted Backcrossing to Develop an Elite Cytoplasmic Male Sterility Line in Rice

    Directory of Open Access Journals (Sweden)

    Asadollah Ahmadikhah

    2015-07-01

    Full Text Available Cytoplasmic male sterility (CMS is a cornerstone of hybrid production in many crops. In three-line hybrid systems, use of CMS, maintainer, and fertility restorer lines is necessary for production of hybrid seeds. Limited resources of CMS and low variation of CMS lines cause genetic vulnerability to pathogens. Therefore, diversifying the CMS sources is indispensible for a sustainable production system of hybrid seed. In this study, we attempted for the first time to transfer CMS into maintainer line Yosen B in restricted generations using the marker-assisted backcrossing (MABC method. The resultant F hybrid of IR68897 A/Yosen B cross was backcrossed to Yosen B, and CMS plants in each backcross generation (from BCF to BCF were selected based on phenotyping test and MABC. Molecular assessment of backcross progenies was conducted using a mitochondrial CMS-specific marker and 34 polymorphic nuclear simple-sequence repeat (SSR markers in early generations (from BCF to BCF and was continued using 9 additional SSRs and 82 inter-simple sequence repeat (ISSR markers in BCF. A MABC strategy could successfully recover the recurrent parent genome (RPG in BCF generation, and decreased heterozygosity of final CMS plants. Restorability test with known wild-abortive restorer lines (viz. IR36 and IR24 showed that combination of Yosen A × IR24 could produce highly fertile F hybrid. Evaluation of some important agronomic traits of the final CMS line (BCF at field condition showed that it was comparable to the original maintainer fertile counterpart. Phenotypic and marker-assisted selections could considerably decrease the time needed for full recovery of RPG so that final CMS line could show a high similarity to original fertile counterpart.

  11. Mitochondrial ORF79 levels determine pollen abortion in cytoplasmic male sterile rice.

    Science.gov (United States)

    Kazama, Tomohiko; Itabashi, Etsuko; Fujii, Shinya; Nakamura, Takahiro; Toriyama, Kinya

    2016-03-01

    Cytoplasmic male sterility (CMS) is an important agricultural trait characterized by lack of functional pollen, and caused by ectopic and defective mitochondrial gene expression. The pollen function in CMS plants is restored by the presence of nuclear-encoded restorer of fertility (Rf) genes. Previously, we cloned Rf2, which restores the fertility of Lead Rice (LD)-type CMS rice. However, neither the function of Rf2 nor the identity of the mitochondrial gene causing CMS has been determined in LD-CMS rice. Here, we show that the mitochondrial gene orf79 acts as a CMS-associated gene in LD-CMS rice, similar to its role in BT-CMS rice originating from Chinsurah Boro II, and Rf2 weakly restores fertility in BT-CMS rice. We also show that RF2 promotes degradation of atp6-orf79 RNA in a different manner from that of RF1, which is the Rf gene product in BT-CMS rice. The amount of ORF79 protein in LD-CMS rice was one-twentieth of the amount in BT-CMS rice. The difference in ORF79 protein levels probably accounts for the mild and severe pollen defects in LD-CMS and BT-CMS rice, respectively. In the presence of Rf2, accumulation of ORF79 was reduced to almost zero and 25% in LD-CMS and BT-CMS rice, respectively, which probably accounts for the complete and weak fertility restoration abilities of Rf2 in LD-CMS and BT-CMS rice, respectively. These observations indicate that the amount of ORF79 influences the pollen fertility in two strains of rice in which CMS is induced by orf79. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  12. Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2015-01-01

    Full Text Available The bulk of ATP synthesis in plants is performed by ATP synthase, the main bioenergetics engine of cells, operating both in mitochondria and in chloroplasts. The reaction mechanism of ATP synthase has been studied in detail for over half a century; however, its optimal performance depends also on the steady delivery of ATP synthase substrates and the removal of its products. For mitochondrial ATP synthase, we analyze here the provision of stable conditions for (i the supply of ADP and Mg2+, supported by adenylate kinase (AK equilibrium in the intermembrane space, (ii the supply of phosphate via membrane transporter in symport with H+, and (iii the conditions of outflow of ATP by adenylate transporter carrying out the exchange of free adenylates. We also show that, in chloroplasts, AK equilibrates adenylates and governs Mg2+ contents in the stroma, optimizing ATP synthase and Calvin cycle operation, and affecting the import of inorganic phosphate in exchange with triose phosphates. It is argued that chemiosmosis is not the sole component of ATP synthase performance, which also depends on AK-mediated equilibrium of adenylates and Mg2+, adenylate transport and phosphate release and supply.

  13. 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

  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. 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.

  16. Molecular cloning and characterization of a cytoplasmic cyclophilin ...

    African Journals Online (AJOL)

    Jane

    2011-08-08

    Aug 8, 2011 ... In real-time qPCR analysis, the Sc-CyP gene showed induced expression under ... signaling pathway was also existed in plants (Luan et al.,. 1993). ... Construction of prokaryotic expression vector of Sc-CyP gene. pET29a (+) ...

  17. Studying genome heterogeneity within the arbuscular mycorrhizal fungal cytoplasm

    NARCIS (Netherlands)

    Boon, E.; Halary, S.; Bapteste, E.; Hijri, M.

    2015-01-01

    Although heterokaryons have been reported in nature, multicellular organisms are generally assumed genetically homogeneous. Here, we investigate the case of arbuscular mycorrhizal fungi (AMF) that form symbiosis with plant roots. The growth advantages they confer to their hosts are of great

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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...

  3. Conformational alterations resulting from mutations in cytoplasmic domains of the alpha subunit of the Na,K-ATPase

    DEFF Research Database (Denmark)

    Blostein, R; Daly, S E; MacAulay, Nanna

    1998-01-01

    This paper summarizes experiments concerned with the functional consequences of mutations in cytoplasmic regions of the alpha 1 subunit of the Na,K-ATPase, in particular the amino terminus, the first cytoplasmic loop between transmembrane segments M2 and M3, and the major cytoplasmic loop between...

  4. Proteomic response of Bacillus subtilis to lantibiotics reflects differences in interaction with the cytoplasmic membrane

    NARCIS (Netherlands)

    Wenzel, M.; Kohl, B.; Münch, D.; Raatschen, N.; Albada, H.B.; Hamoen, L.; Metzler-Nolte, N.; Sahl, H.G.; Bandow, J.E.

    2012-01-01

    Mersacidin, gallidermin, and nisin are lantibiotics, antimicrobial peptides containing lanthionine. They show potent antibacterial activity. All three interfere with cell wall biosynthesis by binding lipid II, but they display different levels of interaction with the cytoplasmic membrane. On one end

  5. Cytoplasmic Dynein Regulation by Subunit Heterogeneity and Its Role in Apical Transport

    Science.gov (United States)

    Tai, Andrew W.; Chuang, Jen-Zen; Sung, Ching-Hwa

    2001-01-01

    Despite the existence of multiple subunit isoforms for the microtubule motor cytoplasmic dynein, it has not yet been directly shown that dynein complexes with different compositions exhibit different properties. The 14-kD dynein light chain Tctex-1, but not its homologue RP3, binds directly to rhodopsin's cytoplasmic COOH-terminal tail, which encodes an apical targeting determinant in polarized epithelial Madin-Darby canine kidney (MDCK) cells. We demonstrate that Tctex-1 and RP3 compete for binding to dynein intermediate chain and that overexpressed RP3 displaces endogenous Tctex-1 from dynein complexes in MDCK cells. Furthermore, replacement of Tctex-1 by RP3 selectively disrupts the translocation of rhodopsin to the MDCK apical surface. These results directly show that cytoplasmic dynein function can be regulated by its subunit composition and that cytoplasmic dynein is essential for at least one mode of apical transport in polarized epithelia. PMID:11425878

  6. Organization of the cytoplasmic reticulum in the central vacuole of parenchyma cells in Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Tomasz J. Wodzicki

    2015-01-01

    Full Text Available An elaborate and complex cytoplasmic reticulum composed of fine filaments and lamellae ranging from 0.1 to 4 microns in size is revealed by viewing the central vacuole of onion bulb parenchyma cells with the scanning election microscope. The larger cytoplasmic strands, visible with the light microscope, are composed of numerous smaller filaments (some tubular which might explain the observed bidirectional movement of particles in these larger strands. The finely divided cytoplasmic network of filaments is continuous with the parietal cytoplasm inclosing the vacuolar sap. In these highly vacuolated cells the mass of the protoplast is in the form of an intravacuolar reticulum immersed in the cell sap. The probable significance of the vacuolar sap in relation to physiological processes of the cell is discussed.

  7. Characterization of Novel Cytoplasmic PARP in the Brain of Octopus vulgaris

    Science.gov (United States)

    DE LISA, EMILIA; DE MAIO, ANNA; MOROZ, LEONID L.; MOCCIA, FRANCESCO; MENNELLA, MARIA ROSARIA FARAONE; DI COSMO, ANNA

    2014-01-01

    Recent investigation has focused on the participation of the poly (ADP-ribose) polymerase (PARP) reaction in the invertebrate central nervous system (CNS) during the process of long-term memory (LTM). In this paper, we characterize, localize, and assign a possible role to a cytoplasmic PARP in the brain of Octopus vulgaris. PARP activity was assayed in optic lobes, supraesophageal mass, and optic nerves. The highest levels of enzyme were found in the cytoplasmic fraction. Hyper-activation of the enzyme was detected in Octopus brain after visual discrimination training. Finally, cytoplasmic PARP was found to inhibit Octopus vulgaris actin polymerization. We propose that the cytoplasmic PARP plays a role in vivo to induce the cytoskeletonal reorganization that occurs during learning-induced neuronal plasticity. PMID:22815366

  8. Evaluation of antineutrophil cytoplasmic antibody seroconversion induced by minocycline, sulfasalazine, or penicillamine

    NARCIS (Netherlands)

    Choi, HK; Slot, MC; Pan, GL; Weissbach, CA; Niles, JL; Merkel, PA

    Objective, Case reports have suggested that minocycline, sulfasalazine, and penicillamine are associated with antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis, This study evaluated ANCA seroconversion due to these agents in serum samples prospectively collected in randomized,

  9. Activation of chromatin degradation by a protein factor of thymocyte cytoplasm of irradiated mice

    International Nuclear Information System (INIS)

    Soldatenkov, V.A.; Filippovich, I.V.

    1986-01-01

    A cytoplasmic thymocyte fraction isolated 1 h after irradiation of mice accelerates chromatin degradation in isolated nuclei. Treatment of the cytoplasmic fraction by heat and injection of cycloheximide to mice prevent the acceleration of DNA degradation. The analysis of the chromatin degradation products and the kinetics of this process at acid and alkaline pH shows that activation of DNA degradation in thymocytes by a factor obtained from the irradiated cell cytoplasm is specific for a Ca 2+ , Mg 2+ -dependent enzyme. The time- and dose-dependent parameters of the appearance in the thymocyte cytoplasm of the factor influencing degradation of chromatin are in a good agreement with both the time of the onset of its postirradiation degradation and the dose dependence of this process

  10. Anticorpos contra o citoplasma de neutrófilos Antineutrophil cytoplasmic antibodies

    Directory of Open Access Journals (Sweden)

    Ari Stiel Radu

    2005-07-01

    Full Text Available A descoberta do marcador sorológico denominado anticorpo anticitoplasma de neutrófilos revolucionou o diagnóstico e o seguimento das vasculites pulmonares, especialmente da granulomatose de Wegener. Seu padrão pode ser citoplasmático e perinuclear. Sua titulação auxilia no diagnóstico e no seguimento das vasculites pulmonares.The discovery of the serological markers known as antineutrophil cytoplasmic antibodies revolutionized the diagnosis and follow-up treatment of the various forms of pulmonary vasculitis, especially that of Wegener's granulomatosis. The antineutrophil cytoplasmic antibodies pattern can be cytoplasmic or perinuclear. Determination of antineutrophil cytoplasmic antibodies titers aids the diagnosis and follow-up treatment of pulmonary vasculitis.

  11. The Protective Effect of Cell Wall and Cytoplasmic Fraction of Selenium Enriched Yeast on 1, 2-Dimethylhydrazine-induced Damage in Liver

    Directory of Open Access Journals (Sweden)

    Mitra Dadrass

    2014-02-01

    Full Text Available Background: 1, 2-Dimethylhydrazine (DMH enhances lipid peroxidation rate by tumor mitochondria than normal tissue counterpart and causes many disorders in antioxidant system in liver. It also increases the level of enzymes that metabolize toxin in liver and colon. The aim of this study was to evaluate the alteration of liver and its enzymes after DMH injection and evaluate protective effect of cell wall and cytoplasmic fractions of Saccharomyces cereviseae enriched with selenium (Se on these tissues. Materials and Methods: Forty eight female rats were prepared and acclimatized to the laboratory conditions for two weeks, and all animals received 1, 2- dimethyl hydrazine chloride (40 mg/kg body weight twice a week for 4 weeks except healthy control. At first colon carcinoma (aberrant crypt foci confirmed by light microscope. Then the changes resulting from injection of DMH on liver of animals in initial and advanced stages of colon cancer were examined. In addition, the protective effect of cell wall and cytoplasmic fractions of Selenium-enriched S. cerevisiae were investigated in two phases. First phase in initial stage and second phase in advanced stage of colon cancer were performed respectively. Forty weeks following the first DMH injection, all survived animals were sacrificed. Then, colon and liver removed and exsanguinated by heart puncture. For measuring the levels of enzymes (AST, ALT, and ALP, a commercial kit (Parsazmoon, Iran and an autoanalyzer (BT 3000 Pluse, Italy were used. Results: The results showed that subcutaneous injection of DMH increased the ALT, AST, and ALP levels up to 78.5, 161.38, and 275.88 U/L compared to the control, respectively. Moreover, statistical analysis in both phases of experiment revealed that the enzyme levels were decreased in the treated groups in comparison with the DMH-injected group, while the levels of these enzymes were lower in the control group. Conclusion: It should be concluded that

  12. The membrane-cytoplasm interface of integrin alpha subunits is critical for receptor latency.

    OpenAIRE

    Briesewitz, R; Kern, A; Smilenov, L B; David, F S; Marcantonio, E E

    1996-01-01

    Localization of integrin receptors to focal contact sites occurs upon ligand binding. This activity is latent, since unoccupied integrin receptors do not localize to focal contacts. Deletion analysis has revealed that the alpha cytoplasmic domains is required for the maintenance of integrin receptor latency. Our current hypothesis for the mechanism of integrin post-ligand binding events is that there is a change in relationship of alpha and beta cytoplasmic domains, which overcomes receptor l...

  13. Control of cytoplasmic and nuclear protein kinase A by phosphodiesterases and phosphatases in cardiac myocytes

    Science.gov (United States)

    Haj Slimane, Zeineb; Bedioune, Ibrahim; Lechêne, Patrick; Varin, Audrey; Lefebvre, Florence; Mateo, Philippe; Domergue-Dupont, Valérie; Dewenter, Matthias; Richter, Wito; Conti, Marco; El-Armouche, Ali; Zhang, Jin; Fischmeister, Rodolphe; Vandecasteele, Grégoire

    2014-01-01

    Aims The cAMP-dependent protein kinase (PKA) mediates β-adrenoceptor (β-AR) regulation of cardiac contraction and gene expression. Whereas PKA activity is well characterized in various subcellular compartments of adult cardiomyocytes, its regulation in the nucleus remains largely unknown. The aim of the present study was to compare the modalities of PKA regulation in the cytoplasm and nucleus of cardiomyocytes. Methods and results Cytoplasmic and nuclear cAMP and PKA activity were measured with targeted fluorescence resonance energy transfer probes in adult rat ventricular myocytes. β-AR stimulation with isoprenaline (Iso) led to fast cAMP elevation in both compartments, whereas PKA activity was fast in the cytoplasm but markedly slower in the nucleus. Iso was also more potent and efficient in activating cytoplasmic than nuclear PKA. Similar slow kinetics of nuclear PKA activation was observed upon adenylyl cyclase activation with L-858051 or phosphodiesterase (PDE) inhibition with 3-isobutyl-1-methylxantine. Consistently, pulse stimulation with Iso (15 s) maximally induced PKA and myosin-binding protein C phosphorylation in the cytoplasm, but marginally activated PKA and cAMP response element-binding protein phosphorylation in the nucleus. Inhibition of PDE4 or ablation of the Pde4d gene in mice prolonged cytoplasmic PKA activation and enhanced nuclear PKA responses. In the cytoplasm, phosphatase 1 (PP1) and 2A (PP2A) contributed to the termination of PKA responses, whereas only PP1 played a role in the nucleus. Conclusion Our study reveals a differential integration of cytoplasmic and nuclear PKA responses to β-AR stimulation in cardiac myocytes. This may have important implications in the physiological and pathological hypertrophic response to β-AR stimulation. PMID:24550350

  14. Adenosine Triphosphate (ATP Is a Candidate Signaling Molecule in the Mitochondria-to-Nucleus Retrograde Response Pathway

    Directory of Open Access Journals (Sweden)

    Zhengchang Liu

    2013-03-01

    Full Text Available Intracellular communication from the mitochondria to the nucleus is achieved via the retrograde response. In budding yeast, the retrograde response, also known as the RTG pathway, is regulated positively by Rtg1, Rtg2, Rtg3 and Grr1 and negatively by Mks1, Lst8 and two 14-3-3 proteins, Bmh1/2. Activation of retrograde signaling leads to activation of Rtg1/3, two basic helix-loop-helix leucine zipper transcription factors. Rtg1/3 activation requires Rtg2, a cytoplasmic protein with an N-terminal adenosine triphosphate (ATP binding domain belonging to the actin/Hsp70/sugar kinase superfamily. The critical regulatory step of the retrograde response is the interaction between Rtg2 and Mks1. Rtg2 binds to and inactivates Mks1, allowing for activation of Rtg1/3 and the RTG pathway. When the pathway is inactive, Mks1 has dissociated from Rtg2 and bound to Bmh1/2, preventing activation of Rtg1/3. What signals association or disassociation of Mks1 and Rtg2 is unknown. Here, we show that ATP at physiological concentrations dissociates Mks1 from Rtg2 in a highly cooperative fashion. We report that ATP-mediated dissociation of Mks1 from Rtg2 is conserved in two other fungal species, K. lactis and K. waltii. Activation of Rtg1/3 upregulates expression of genes encoding enzymes catalyzing the first three reactions of the Krebs cycle, which is coupled to ATP synthesis through oxidative phosphorylation. Therefore, we propose that the retrograde response is an ATP homeostasis pathway coupling ATP production with ATP-mediated repression of the retrograde response by releasing Mks1 from Rtg2.

  15. 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...

  16. 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

  17. 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

  18. 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+.

  19. 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.

  20. 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