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Sample records for respiration oxidative phosphorylation

  1. Oxidative phosphorylation revisited

    DEFF Research Database (Denmark)

    Nath, Sunil; Villadsen, John

    2015-01-01

    The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic...

  2. Inhibition of oxidative phosphorylation in ascites tumor mitochondria and cells by intramitochondrial Ca2+.

    Science.gov (United States)

    Villalobo, A; Lehninger, A L

    1980-03-25

    Accumulation of Ca2+ (+ phosphate) by respiring mitochondria from Ehrlich ascites or AS30-D hepatoma tumor cells inhibits subsequent phosphorylating respiration in response to ADP. The respiratory chain is still functional since a proton-conducting uncoupler produces a normal stimulation of electron transport. The inhibition of phosphorylating respiration is caused by intramitochondrial Ca2+ (+ phosphate). ATP + Mg2+ together, but not singly, prevents the inhibitory action of Ca2+. Neither AMP, GTP, GDP, nor any other nucleoside 5'-triphosphate or 5'-diphosphate could replace ATP in this effect. Phosphorylating respiration on NAD(NADP)-linked substrates was much more susceptible to the inhibitory effect of intramitochondrial Ca2+ than succinate-linked respiration. Significant inhibition of oxidative phosphorylation is given by the endogenous Ca2+ present in freshly isolated tumor mitochondria. The phosphorylating respiration of permeabilized Ehrlich ascites tumor cells is also inhibited by Ca2+ accumulated by the mitochondria in situ. Possible causes of the Ca2+-induced inhibition of oxidative phosphorylation are considered.

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

    International Nuclear Information System (INIS)

    Egana, E.; Diaz, G.

    1975-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-11-01

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

  5. Peroxides and radiation impairment of oxidative phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Dovgii, I E; Akoev, I G

    1975-09-01

    An increase in the peroxidase activity of the mitochondria and a simultaneous rise in the amount of peroxide compounds, which are half lipid-like substances, are detected within the first 10 minutes after irradiation (1000 r). A mechanism of radiation impairment of oxidative phosphorylation is connected with the penetration of its inhibitors to the mitochondria due to the disturbed permeability of membranes affected by peroxides.

  6. Respiration and phosphorylation in liver and kidney mitochondria of rats exposed to high-energy gamma and beta radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mokhoreva, S I; Vetlugina, N S

    1973-01-01

    The effect of whole-body irradiation with ..gamma.. rays (radiation source /sup 60/Co) at 40 rad and ..beta.. rays (source, a linear accelerator, electron energy 25 MeV) at 43 rad on oxidative phosphorylation in liver and kidney mitochondria was studied in rats. Gamma radiation gradually slowed the esterification of phosphate and respiratory rate during the oxidation of succinate in the liver and kidney mitochondria. The decrease was largest on day 15 after irradiation. However, the P/O ratio did not decrease by more than 10 to 12 percent. Despite the oxidation of glutamate in the mitochondria, respiration, phosphate consumption, and P/O ratio scarcely changed. Irradiation with electrons slowed the rate of oxidation of succinate and glutamate in liver mitochondria within 3 to 7 days. Phosphate consumption decreased at the same time so that the P/O ratio remained unchanged. Beta irradiation had virtually no effect on liver mitochondria. There is a discussion of the mechanism of action of high-energy radiation on the phosphorylation system of the mitochondria.

  7. Modelling the Krebs cycle and oxidative phosphorylation.

    Science.gov (United States)

    Korla, Kalyani; Mitra, Chanchal K

    2014-01-01

    The Krebs cycle and oxidative phosphorylation are the two most important sets of reactions in a eukaryotic cell that meet the major part of the total energy demands of a cell. In this paper, we present a computer simulation of the coupled reactions using open source tools for simulation. We also show that it is possible to model the Krebs cycle with a simple black box with a few inputs and outputs. However, the kinetics of the internal processes has been modelled using numerical tools. We also show that the Krebs cycle and oxidative phosphorylation together can be combined in a similar fashion - a black box with a few inputs and outputs. The Octave script is flexible and customisable for any chosen set-up for this model. In several cases, we had no explicit idea of the underlying reaction mechanism and the rate determining steps involved, and we have used the stoichiometric equations that can be easily changed as and when more detailed information is obtained. The script includes the feedback regulation of the various enzymes of the Krebs cycle. For the electron transport chain, the pH gradient across the membrane is an essential regulator of the kinetics and this has been modelled empirically but fully consistent with experimental results. The initial conditions can be very easily changed and the simulation is potentially very useful in a number of cases of clinical importance.

  8. Parkinson's disease associated with impaired oxidative phosphorylation

    International Nuclear Information System (INIS)

    Finsterer, J.; Jarius, C.; Baumgartner, M.

    2001-01-01

    Parkinson's disease may be due to primary or secondary oxidative phosphorylation (OXPHOS) defects. In a 76-year-old man with Parkinson's disease since 1992, slightly but recurrently elevated creatine phosphokinase, recurrently elevated blood glucose, thickening of the left ventricular myocardium, bifascicular block and hypacusis were found. Cerebral MRI showed atrophy, periventricular demyelination, multiple, disseminated, supra- and infratentorial lacunas, and haemosiderin deposits in both posterior horns. Muscle biopsy showed typical features of an OXPHOS defect. Whether the association of Parkinson's disease and impaired OXPHOS was causative or coincidental remains unknown. Possibly, the mitochondrial defect acted as an additional risk factor for Parkinson's disease or the OXPHOS defect worsened the preexisting neurological impairments by a cumulative or synergistic mechanism. In conclusion, this case shows that Parkinson's disease may be associated with a mitochondrially or nuclearly encoded OXPHOS defect, manifesting as hypacusis, myopathy, axonal polyneuropathy, cardiomyopathy and recurrent subclinical ischaemic strokes and haemorrhages. (orig.)

  9. 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.

  10. Reduced coupling of oxidative phosphorylation in vivo precedes electron transport chain defects due to mild oxidative stress in mice.

    Directory of Open Access Journals (Sweden)

    Michael P Siegel

    Full Text Available Oxidative stress and mitochondrial function are at the core of many degenerative conditions. However, the interaction between oxidative stress and in vivo mitochondrial function is unclear. We used both pharmacological (2 week paraquat (PQ treatment of wild type mice and transgenic (mice lacking Cu, Zn-superoxide dismutase (SOD1(-/- models to test the effect of oxidative stress on in vivo mitochondrial function in skeletal muscle. Magnetic resonance and optical spectroscopy were used to measure mitochondrial ATP and oxygen fluxes and cell energetic state. In both models of oxidative stress, coupling of oxidative phosphorylation was significantly lower (lower P/O at rest in vivo in skeletal muscle and was dose-dependent in the PQ model. Despite this reduction in efficiency, in vivo mitochondrial phosphorylation capacity (ATPmax was maintained in both models, and ex vivo mitochondrial respiration in permeabilized muscle fibers was unchanged following PQ treatment. In association with the reduced P/O, PQ treatment led to a dose-dependent reduction in PCr/ATP ratio and increased phosphorylation of AMPK. These results indicate that oxidative stress uncouples oxidative phosphorylation in vivo and results in energetic stress in the absence of defects in the mitochondrial electron transport chain.

  11. Interaction of butylated hydroxyanisole with mitochondrial oxidative phosphorylation.

    Science.gov (United States)

    Fusi, F; Sgaragli, G; Murphy, M P

    1992-03-17

    The antioxidant, butylated hydroxyanisole (BHA), has a number of effects on mitochondrial oxidative phosphorylation. In this study we apply the novel approach developed by Brand (Brand MD, Biochim Biophys Acta 1018: 128-133, 1990) to investigate the site of action of BHA on oxidative phosphorylation in rat liver mitochondria. Using this approach we show that BHA increases the proton leak through the mitochondrial inner membrane and that it also inhibits the delta p (proton motive force across the mitochondrial inner membrane) generating system, but has no effect on the phosphorylation system. This demonstrates that compounds having pleiotypic effects on mitochondrial oxidative phosphorylation in vitro can be analysed and their many effects distinguished. This approach is of general use in analysing many other compounds of pharmacological interest which interact with mitochondria. The implications of these results for the mechanism of interaction of BHA with mitochondrial oxidative phosphorylation are discussed.

  12. Rosamines targeting the cancer oxidative phosphorylation pathway.

    Directory of Open Access Journals (Sweden)

    Siang Hui Lim

    Full Text Available Reprogramming of energy metabolism is pivotal to cancer, so mitochondria are potential targets for anticancer therapy. A prior study has demonstrated the anti-proliferative activity of a new class of mitochondria-targeting rosamines. This present study describes in vitro cytotoxicity of second-generation rosamine analogs, their mode of action, and their in vivo efficacies in a tumor allografted mouse model. Here, we showed that these compounds exhibited potent cytotoxicity (average IC50<0.5 µM, inhibited Complex II and ATP synthase activities of the mitochondrial oxidative phosphorylation pathway and induced loss of mitochondrial transmembrane potential. A NCI-60 cell lines screen further indicated that rosamine analogs 4 and 5 exhibited potent antiproliferative effects with Log10GI50 = -7 (GI50 = 0.1 µM and were more effective against a colorectal cancer sub-panel than other cell lines. Preliminary in vivo studies on 4T1 murine breast cancer-bearing female BALB/c mice indicated that treatment with analog 5 in a single dosing of 5 mg/kg or a schedule dosing of 3 mg/kg once every 2 days for 6 times (q2d×6 exhibited only minimal induction of tumor growth delay. Our results suggest that rosamine analogs may be further developed as mitochondrial targeting agents. Without a doubt proper strategies need to be devised to enhance tumor uptake of rosamines, i.e. by integration to carrier molecules for better therapeutic outcome.

  13. Genetics Home Reference: combined oxidative phosphorylation deficiency 1

    Science.gov (United States)

    ... a severe condition that primarily impairs neurological and liver function. Most people with combined oxidative phosphorylation deficiency 1 have severe brain dysfunction (encephalopathy) that worsens over time; they also have difficulty ...

  14. Oxidative stress negatively affects human sperm mitochondrial respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Pinto Provenzano, Sara; Montagna, Daniela Domenica; Coppola, Lamberto; Zara, Vincenzo

    2013-07-01

    To correlate the level of oxidative stress in serum and seminal fluid and the level of sperm deoxyribonucleic acid (DNA) fragmentation with sperm mitochondrial respiratory efficiency. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. A possible relationship between sperm mitochondrial respiratory efficiency, the level of oxidative stress, and the level of sperm DNA fragmentation was investigated. Sperm motility was positively correlated with mitochondrial respiration but negatively correlated with oxidative stress and DNA fragmentation. Interestingly, sperm mitochondrial respiratory activity was negatively affected by oxidative stress and DNA fragmentation. Our data indicate that sperm mitochondrial respiration is decreased in patients with high levels of reactive oxygen species by an uncoupling between electron transport and adenosine triphosphate synthesis. This reduction in mitochondrial functionality might be 1 of the reasons responsible for the decrease in spermatozoa motility. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Cardiac, Skeletal, and smooth muscle mitochondrial respiration

    DEFF Research Database (Denmark)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I

    2014-01-01

    , skeletal, and smooth muscle was harvested from a total of 22 subjects (53±6 yrs) and mitochondrial respiration assessed in permeabilized fibers. Complex I+II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac, skeletal, to smooth muscle (54±1; 39±4; 15......±1 pmol•s(-1)•mg (-1), prespiration rates were normalized by CS (respiration...... per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, Complex I state 2 normalized for CS activity, an index of non-phosphorylating respiration per mitochondrial content, increased progressively from cardiac, skeletal...

  16. 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.

  17. Training-induced adaptation of oxidative phosphorylation in skeletal muscles.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2003-08-15

    Muscle training/conditioning improves the adaptation of oxidative phosphorylation in skeletal muscles to physical exercise. However, the mechanisms underlying this adaptation are still not understood fully. By quantitative analysis of the existing experimental results, we show that training-induced acceleration of oxygen-uptake kinetics at the onset of exercise and improvement of ATP/ADP stability due to physical training are mainly caused by an increase in the amount of mitochondrial proteins and by an intensification of the parallel activation of ATP usage and ATP supply (increase in direct stimulation of oxidative phosphorylation complexes accompanying stimulation of ATP consumption) during exercise.

  18. Genetic defects in the oxidative phosphorylation (OXPHOS) system.

    NARCIS (Netherlands)

    Janssen, R.J.R.J.; Heuvel, L.P.W.J. van den; Smeitink, J.A.M.

    2004-01-01

    The oxidative phosphorylation (OXPHOS) system consists of five multiprotein complexes and two mobile electron carriers embedded in the lipid bilayer of the mitochondrial inner membrane. With the exception of complex II and the mobile carriers, the other parts of the OXPHOS system are under dual

  19. The upper and lower limits of the mechanistic stoichiometry of mitochondrial oxidative phosphorylation. Stoichiometry of oxidative phosphorylation.

    Science.gov (United States)

    Beavis, A D; Lehninger, A L

    1986-07-15

    Determination of the intrinsic or mechanistic P/O ratio of oxidative phosphorylation is difficult because of the unknown magnitude of leak fluxes. Applying a new approach developed to overcome this problem (see our preceding paper in this journal), the relationships between the rate of O2 uptake [( Jo)3], the net rate of phosphorylation (Jp), the P/O ratio, and the respiratory control ratio (RCR) have been determined in rat liver mitochondria when the rate of phosphorylation was systematically varied by three specific means. (a) When phosphorylation is titrated with carboxyatractyloside, linear relationships are observed between Jp and (Jo)3. These data indicate that the upper limit of the mechanistic P/O ratio is 1.80 for succinate and 2.90 for 3-hydroxybutyrate oxidation. (b) Titration with malonate or antimycin yields linear relationships between Jp and (Jo)3. These data give the lower limit of the mechanistic P/O ratio of 1.63 for succinate and 2.66 for 3-hydroxybutyrate oxidation. (c) Titration with a protonophore yields linear relationships between Jp, (Jo)3, and (Jo)4 and between P/O and 1/RCR. Extrapolation of the P/O ratio to 1/RCR = 0 yields P/O ratios of 1.75 for succinate and 2.73 for 3-hydroxybutyrate oxidation which must be equal to or greater than the mechanistic stoichiometry. When published values for the H+/O and H+/ATP ejection ratios are taken into consideration, these measurements suggest that the mechanistic P/O ratio is 1.75 for succinate oxidation and 2.75 for NADH oxidation.

  20. Training-induced adaptation of oxidative phosphorylation in skeletal muscles.

    OpenAIRE

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2003-01-01

    Muscle training/conditioning improves the adaptation of oxidative phosphorylation in skeletal muscles to physical exercise. However, the mechanisms underlying this adaptation are still not understood fully. By quantitative analysis of the existing experimental results, we show that training-induced acceleration of oxygen-uptake kinetics at the onset of exercise and improvement of ATP/ADP stability due to physical training are mainly caused by an increase in the amount of mitochondrial protein...

  1. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

    Science.gov (United States)

    Anderson, I. C.; Levine, J. S.

    1986-01-01

    An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

  2. Osteoblast-like MC3T3-E1 Cells Prefer Glycolysis for ATP Production but Adipocyte-like 3T3-L1 Cells Prefer Oxidative Phosphorylation.

    Science.gov (United States)

    Guntur, Anyonya R; Gerencser, Akos A; Le, Phuong T; DeMambro, Victoria E; Bornstein, Sheila A; Mookerjee, Shona A; Maridas, David E; Clemmons, David E; Brand, Martin D; Rosen, Clifford J

    2018-06-01

    Mesenchymal stromal cells (MSCs) are early progenitors that can differentiate into osteoblasts, chondrocytes, and adipocytes. We hypothesized that osteoblasts and adipocytes utilize distinct bioenergetic pathways during MSC differentiation. To test this hypothesis, we compared the bioenergetic profiles of preosteoblast MC3T3-E1 cells and calvarial osteoblasts with preadipocyte 3T3L1 cells, before and after differentiation. Differentiated MC3T3-E1 osteoblasts met adenosine triphosphate (ATP) demand mainly by glycolysis with minimal reserve glycolytic capacity, whereas nondifferentiated cells generated ATP through oxidative phosphorylation. A marked Crabtree effect (acute suppression of respiration by addition of glucose, observed in both MC3T3-E1 and calvarial osteoblasts) and smaller mitochondrial membrane potential in the differentiated osteoblasts, particularly those incubated at high glucose concentrations, indicated a suppression of oxidative phosphorylation compared with nondifferentiated osteoblasts. In contrast, both nondifferentiated and differentiated 3T3-L1 adipocytes met ATP demand primarily by oxidative phosphorylation despite a large unused reserve glycolytic capacity. In sum, we show that nondifferentiated precursor cells prefer to use oxidative phosphorylation to generate ATP; when they differentiate to osteoblasts, they gain a strong preference for glycolytic ATP generation, but when they differentiate to adipocytes, they retain the strong preference for oxidative phosphorylation. Unique metabolic programming in mesenchymal progenitor cells may influence cell fate and ultimately determine the degree of bone formation and/or the development of marrow adiposity. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Research.

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

    Science.gov (United States)

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

    2015-06-01

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

  4. Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation

    NARCIS (Netherlands)

    Sutton, N.B.; Atashgahi, S.; Saccenti, E.; Grotenhuis, J.T.C.; Smidt, H.; Rijnaarts, H.H.M.

    2015-01-01

    While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the

  5. Importance of glycolysis and oxidative phosphorylation in advanced melanoma

    Directory of Open Access Journals (Sweden)

    Ho Jonhan

    2012-10-01

    Full Text Available Abstract Serum lactate dehydrogenase (LDH is a prognostic factor for patients with stage IV melanoma. To gain insights into the biology underlying this prognostic factor, we analyzed total serum LDH, serum LDH isoenzymes, and serum lactate in up to 49 patients with metastatic melanoma. Our data demonstrate that high serum LDH is associated with a significant increase in LDH isoenzymes 3 and 4, and a decrease in LDH isoenzymes 1 and 2. Since LDH isoenzymes play a role in both glycolysis and oxidative phosphorylation (OXPHOS, we subsequently determined using tissue microarray (TMA analysis that the levels of proteins associated with mitochondrial function, lactate metabolism, and regulators of glycolysis were all elevated in advanced melanomas compared with nevic melanocytes. To investigate whether in advanced melanoma, the glycolysis and OXPHOS pathways might be linked, we determined expression of the monocarboxylate transporters (MCT 1 and 4. Analysis of a nevus-to-melanoma progression TMA revealed that MCT4, and to a lesser extend MCT1, were elevated with progression to advanced melanoma. Further analysis of human melanoma specimens using the Seahorse XF24 extracellular flux analyzer indicated that metastatic melanoma tumors derived a large fraction of energy from OXPHOS. Taken together, these findings suggest that in stage IV melanomas with normal serum LDH, glycolysis and OXPHOS may provide metabolic symbiosis within the same tumor, whereas in stage IV melanomas with high serum LDH glycolysis is the principle source of energy.

  6. Oxidative Phosphorylation System in Gastric Carcinomas and Gastritis

    Science.gov (United States)

    Skaria, Tom; Wessler, Silja; Cover, Timothy L.; Posselt, Gernot; Sperl, Wolfgang; Kofler, Barbara

    2017-01-01

    Switching of cellular energy production from oxidative phosphorylation (OXPHOS) by mitochondria to aerobic glycolysis occurs in many types of tumors. However, the significance of this switching for the development of gastric carcinoma and what connection it may have to Helicobacter pylori infection of the gut, a primary cause of gastric cancer, are poorly understood. Therefore, we investigated the expression of OXPHOS complexes in two types of human gastric carcinomas (“intestinal” and “diffuse”), bacterial gastritis with and without metaplasia, and chemically induced gastritis by using immunohistochemistry. Furthermore, we analyzed the effect of HP infection on several key mitochondrial proteins. Complex I expression was significantly reduced in intestinal type (but not diffuse) gastric carcinomas compared to adjacent control tissue, and the reduction was independent of HP infection. Significantly, higher complex I and complex II expression was present in large tumors. Furthermore, higher complex II and complex III protein levels were also obvious in grade 3 versus grade 2. No differences of OXPHOS complexes and markers of mitochondrial biogenesis were found between bacterially caused and chemically induced gastritis. Thus, intestinal gastric carcinomas, but not precancerous stages, are frequently characterized by loss of complex I, and this pathophysiology occurs independently of HP infection. PMID:28744336

  7. Oxidative Phosphorylation System in Gastric Carcinomas and Gastritis.

    Science.gov (United States)

    Feichtinger, René G; Neureiter, Daniel; Skaria, Tom; Wessler, Silja; Cover, Timothy L; Mayr, Johannes A; Zimmermann, Franz A; Posselt, Gernot; Sperl, Wolfgang; Kofler, Barbara

    2017-01-01

    Switching of cellular energy production from oxidative phosphorylation (OXPHOS) by mitochondria to aerobic glycolysis occurs in many types of tumors. However, the significance of this switching for the development of gastric carcinoma and what connection it may have to Helicobacter pylori infection of the gut, a primary cause of gastric cancer, are poorly understood. Therefore, we investigated the expression of OXPHOS complexes in two types of human gastric carcinomas ("intestinal" and "diffuse"), bacterial gastritis with and without metaplasia, and chemically induced gastritis by using immunohistochemistry. Furthermore, we analyzed the effect of HP infection on several key mitochondrial proteins. Complex I expression was significantly reduced in intestinal type (but not diffuse) gastric carcinomas compared to adjacent control tissue, and the reduction was independent of HP infection. Significantly, higher complex I and complex II expression was present in large tumors. Furthermore, higher complex II and complex III protein levels were also obvious in grade 3 versus grade 2. No differences of OXPHOS complexes and markers of mitochondrial biogenesis were found between bacterially caused and chemically induced gastritis. Thus, intestinal gastric carcinomas, but not precancerous stages, are frequently characterized by loss of complex I, and this pathophysiology occurs independently of HP infection.

  8. Small structural changes on a hydroquinone scaffold determine the complex I inhibition or uncoupling of tumoral oxidative phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Urra, Félix A., E-mail: felix.urra@qf.uchile.cl [Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, Casilla 7, Santiago (Chile); Córdova-Delgado, Miguel [Departamento de Química Orgánica y Físico-Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1 (Chile); Lapier, Michel; Orellana-Manzano, Andrea [Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, Casilla 7, Santiago (Chile); Acevedo-Arévalo, Luis; Pessoa-Mahana, Hernán; González-Vivanco, Jaime M. [Departamento de Química Orgánica y Físico-Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1 (Chile); Martínez-Cifuentes, Maximiliano [Instituto de Química de Recursos Naturales, Universidad de Talca, Casilla 747, Talca (Chile); and others

    2016-01-15

    Mitochondria participate in several distinctiveness of cancer cell, being a promising target for the design of anti-cancer compounds. Previously, we described that ortho-carbonyl hydroquinone scaffold 14 inhibits the complex I-dependent respiration with selective anti-proliferative effect on mouse mammary adenocarcinoma TA3/Ha cancer cells; however, the structural requirements of this hydroquinone scaffold to affect the oxidative phosphorylation (OXPHOS) of cancer cells have not been studied in detail. Here, we characterize the mitochondrial metabolism of TA3/Ha cancer cells, which exhibit a high oxidative metabolism, and evaluate the effect of small structural changes of the hydroquinone scaffold 14 on the respiration of this cell line. Our results indicate that these structural changes modify the effect on OXPHOS, obtaining compounds with three alternative actions: inhibitors of complex I-dependent respiration, uncoupler of OXPHOS and compounds with both actions. To confirm this, the effect of a bicyclic hydroquinone (9) was evaluated in isolated mitochondria. Hydroquinone 9 increased mitochondrial respiration in state 4o without effects on the ADP-stimulated respiration (state 3{sub ADP}), decreasing the complexes I and II-dependent respiratory control ratio. The effect on mitochondrial respiration was reversed by 6-ketocholestanol addition, indicating that this hydroquinone is a protonophoric uncoupling agent. In intact TA3/Ha cells, hydroquinone 9 caused mitochondrial depolarization, decreasing intracellular ATP and NAD(P)H levels and GSH/GSSG ratio, and slightly increasing the ROS levels. Moreover, it exhibited selective NAD(P)H availability-dependent anti-proliferative effect on cancer cells. Therefore, our results indicate that the ortho-carbonyl hydroquinone scaffold offers the possibility to design compounds with specific actions on OXPHOS of cancer cells. - Highlights: • Small changes on a hydroquinone scaffold modify the action on OXPHOS of cancer

  9. The thermodynamic efficiency of ATP synthesis in oxidative phosphorylation.

    Science.gov (United States)

    Nath, Sunil

    2016-12-01

    As the chief energy source of eukaryotic cells, it is important to determine the thermodynamic efficiency of ATP synthesis in oxidative phosphorylation (OX PHOS). Previous estimates of the thermodynamic efficiency of this vital process have ranged from Lehninger's original back-of-the-envelope calculation of 38% to the often quoted value of 55-60% in current textbooks of biochemistry, to high values of 90% from recent information theoretic considerations, and reports of realizations of close to ideal 100% efficiencies by single molecule experiments. Hence this problem has been reinvestigated from first principles. The overall thermodynamic efficiency of ATP synthesis in the mitochondrial energy transduction OX PHOS process has been found to lie between 40 and 41% from four different approaches based on a) estimation using structural and biochemical data, b) fundamental nonequilibrium thermodynamic analysis, c) novel insights arising from Nath's torsional mechanism of energy transduction and ATP synthesis, and d) the overall balance of cellular energetics. The torsional mechanism also offers an explanation for the observation of a thermodynamic efficiency approaching 100% in some experiments. Applications of the unique, molecular machine mode of functioning of F 1 F O -ATP synthase involving direct inter-conversion of chemical and mechanical energies in the design and fabrication of novel, man-made mechanochemical devices have been envisaged, and some new ways to exorcise Maxwell's demon have been proposed. It is hoped that analysis of the fundamental problem of energy transduction in OX PHOS from a fresh perspective will catalyze new avenues of research in this interdisciplinary field. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Megacomplex organization of the oxidative phosphorylation system by structural analysis of respiratory supercomplexes from potato

    NARCIS (Netherlands)

    Bultema, Jelle B.; Braun, Hans-Peter; Boekema, Egbert J.; Kouřil, Roman

    The individual protein complexes of the oxidative phosphorylation system (OXPHOS complexes 1 to V) specifically interact and form defined supramolecular structures, the so-called "respiratory supercomplexes". Some supercomplexes appear to associate into larger structures, or megacomplexes, such as a

  11. Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria

    DEFF Research Database (Denmark)

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2013-01-01

    The effect of acetone, acetonitrile, dimethyl sulfoxide (DMSO), ethanol and methanol on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria has been studied. All the organic solvents inhibited the oxidative phosphorylation in a concentration dependent manner, but with differences...... in potencies. Among the tested organic solvents, acetonitrile and acetone were more potent than ethanol, methanol, and DMSO. There was no significant difference in oxidative phosphorylation, compared to controls, when the concentrations of acetone was below 1% (v/v), of acetonitrile below 2% (v/v), of DMSO...... below 10% (v/v), of ethanol below 5% or of methanol below 2%, respectively. There was complete inhibition of oxidative phosphorylation at 50% (v/v) of acetone, acetonitrile and ethanol. But in the case of DMSO and methanol there were some residual activities observed at the 50% concentration level. DMSO...

  12. Heritable oxidative phosphorylation differences in a pollutant resistant Fundulus heteroclitus population

    International Nuclear Information System (INIS)

    Du, Xiao; Crawford, Douglas L.; Nacci, Diane E.; Oleksiak, Marjorie F.

    2016-01-01

    Highlights: • Laboratory reared fish from a highly polluted and clean reference population were compared. • Oxidative phosphorylation (e.g., State 3, enzymes, and proton LEAK) was quantified. • Laboratory reared F3 fish from polluted population displayed higher routine metabolism and complex II activity but lower complex I enzyme activity. • Enhanced OxPhos metabolism and toxicity resistance were retained in laboratory reared F3 fish from the polluted population. - Abstract: Populations can adapt to stress including recent anthropogenic pollution. Our published data suggests heritable differences in hepatocyte oxidative phosphorylation (OxPhos) metabolism in field-caught killifish (Fundulus heteroclitus) from the highly polluted Elizabeth River, VA, USA, relative to fish from a nearby, relatively unpolluted reference site in King’s Creek VA. Consistent with other studies showing that Elizabeth River killifish are resistant to some of the toxic effects of certain contaminants, OxPhos measurements in hepatocytes from field-caught King’s Creek but not field-caught Elizabeth River killifish were altered by acute benzo [a] pyrene exposures. To more definitively test whether the enhanced OxPhos metabolism and toxicity resistance are heritable, we measured OxPhos metabolism in a laboratory-reared F3 generation from the Elizabeth River population versus a laboratory-reared F1 generation from the King’s Creek population and compared these results to previous data from the field-caught fish. The F3 Elizabeth River fish compared to F1 King’s Creek fish had significantly higher State 3 respiration (routine metabolism) and complex II activity, and significantly lower complex I activity. The consistently higher routine metabolism in the F3 and field-caught Elizabeth River fish versus F1 and field-caught King’s Creek fish implies a heritable change in OxPhos function. The observation that LEAK, E-State, Complex I and Complex II were different in laboratory bred

  13. Heritable oxidative phosphorylation differences in a pollutant resistant Fundulus heteroclitus population

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xiao, E-mail: xdu@rsmas.miami.edu [Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 (United States); Crawford, Douglas L. [Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 (United States); Nacci, Diane E. [Population Ecology Branch, Atlantic Ecology Division, Office of Research and Development, U.S. Environmental Protection Agency, 27 Tarzwell Dr., Narragansett, RI 02882 (United States); Oleksiak, Marjorie F., E-mail: moleksiak@rsmas.miami.edu [Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 (United States)

    2016-08-15

    Highlights: • Laboratory reared fish from a highly polluted and clean reference population were compared. • Oxidative phosphorylation (e.g., State 3, enzymes, and proton LEAK) was quantified. • Laboratory reared F3 fish from polluted population displayed higher routine metabolism and complex II activity but lower complex I enzyme activity. • Enhanced OxPhos metabolism and toxicity resistance were retained in laboratory reared F3 fish from the polluted population. - Abstract: Populations can adapt to stress including recent anthropogenic pollution. Our published data suggests heritable differences in hepatocyte oxidative phosphorylation (OxPhos) metabolism in field-caught killifish (Fundulus heteroclitus) from the highly polluted Elizabeth River, VA, USA, relative to fish from a nearby, relatively unpolluted reference site in King’s Creek VA. Consistent with other studies showing that Elizabeth River killifish are resistant to some of the toxic effects of certain contaminants, OxPhos measurements in hepatocytes from field-caught King’s Creek but not field-caught Elizabeth River killifish were altered by acute benzo [a] pyrene exposures. To more definitively test whether the enhanced OxPhos metabolism and toxicity resistance are heritable, we measured OxPhos metabolism in a laboratory-reared F3 generation from the Elizabeth River population versus a laboratory-reared F1 generation from the King’s Creek population and compared these results to previous data from the field-caught fish. The F3 Elizabeth River fish compared to F1 King’s Creek fish had significantly higher State 3 respiration (routine metabolism) and complex II activity, and significantly lower complex I activity. The consistently higher routine metabolism in the F3 and field-caught Elizabeth River fish versus F1 and field-caught King’s Creek fish implies a heritable change in OxPhos function. The observation that LEAK, E-State, Complex I and Complex II were different in laboratory bred

  14. Influence of rapid changes in cytosolic pH on oxidative phosphorylation in skeletal muscle: theoretical studies.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2002-07-01

    Cytosolic pH in skeletal muscle may vary significantly because of proton production/consumption by creatine kinase and/or proton production by anaerobic glycolysis. A computer model of oxidative phosphorylation in intact skeletal muscle developed previously was used to study the kinetic effect of these variations on the oxidative phosphorylation system. Two kinds of influence were analysed: (i) via the change in pH across the inner mitochondrial membrane and (ii) via the shift in the equilibrium of the creatine kinase-catalysed reaction. Our simulations suggest that cytosolic pH has essentially no impact on the steady-state fluxes and most metabolite concentrations. On the other hand, rapid acidification/alkalization of cytosol causes a transient decrease/increase in the respiration rate. Furthermore, changes in pH seem to affect significantly the kinetic properties of transition between resting state and active state. An increase in pH brought about by proton consumption by creatine kinase at the onset of exercise lengthens the transition time. At intensive exercise levels this pH increase could lead to loss of the stability of the system, if not compensated by glycolytic H+ production. Thus our theoretical results stress the importance of processes/mechanisms that buffer/compensate for changes in cytosolic proton concentration. In particular, we suggest that the second main role of anaerobic glycolysis, apart from additional ATP supply, may be maintaining the stability of the system at intensive exercise.

  15. Effect of respiration and manganese on oxidative stress resistance of Lactobacillus plantarum WCFS1

    NARCIS (Netherlands)

    Watanabe, M.; Veen, van der S.; Nakajima, H.; Abee, T.

    2012-01-01

    Lactobacillus plantarum is a facultatively anaerobic bacterium that can perform respiration under aerobic conditions in the presence of haem, with vitamin K2 acting as a source of menaquinone. We investigated growth performance and oxidative stress resistance of Lb. plantarum WCFS1 cultures grown in

  16. Temperatures In Compost Landfill Covers As Result Of Methane Oxidation And Compost Respiration

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Merono, A. R.; Pedersen, Rasmus Broen

    2011-01-01

    This study investigated the influence of the temperature on methane (CH4) oxidation and respiration in compost sampled at a full scale biocover implemented at Klintholm landfill exhibiting high temperatures. Compost material was collected at Klintholm landfill and incubated with and without CH4...

  17. Limits to sustainable muscle performance: interaction between glycolysis and oxidative phosphorylation.

    Science.gov (United States)

    Conley, K E; Kemper, W F; Crowther, G J

    2001-09-01

    This paper proposes a mechanism responsible for setting the sustainable level of muscle performance. Our contentions are that the sustainable work rate is determined (i) at the muscle level, (ii) by the ability to maintain ATP supply and (iii) by the products of glycolysis that may inhibit the signal for oxidative phosphorylation. We argue below that no single factor 'limits' sustainable performance, but rather that the flux through and the interaction between glycolysis and oxidative phosphorylation set the level of sustainable ATP supply. This argument is based on magnetic resonance spectroscopy measurements of the sources and sinks for energy in vivo in human muscle and rattlesnake tailshaker muscle during sustained contractions. These measurements show that glycolysis provides between 20% (human muscle) and 40% (tailshaker muscle) of the ATP supply during sustained contractions in these muscles. We cite evidence showing that this high glycolytic flux does not reflect an O(2) limitation or mitochondria operating at their capacity. Instead, this flux reflects a pathway independent of oxidative phosphorylation for ATP supply during aerobic exercise. The consequence of this high glycolytic flux is accumulation of H(+), which we argue inhibits the rise in the signal activating oxidative phosphorylation, thereby restricting oxidative ATP supply to below the oxidative capacity. Thus, both glycolysis and oxidative phosphorylation play important roles in setting the highest steady-state ATP synthesis flux and thereby determine the sustainable level of work by exercising muscle.

  18. Did Respiration or Photosynthesis Come First

    International Nuclear Information System (INIS)

    Broda, E.

    1979-01-01

    The similarity of the mechanisms in photosynthetic and in oxidative phosphorylation suggests a common origin ( convers ion hypothesis). It is proposed that an early form of electron flow with oxidative phosphorylation ("prerespiration"), to terminal electron acceptors available in a reducing biosphere, was supplemented by a photocatalyst capable of a redox reaction. In this way, cyclic photophosphorylation arose. Further stages in evolution were reverse electron flow powered by ATP, to make NADH as a reductant for CO2 , and subsequently noncyclic electron flow. These processes concomitantly provided the oxidants indispensable for full development of oxidative phosphorylation, i.e. for normal respiration: sulphate, O2 and with participation of the nitrificants, nitrite and nitrate. Thus, prerespiration preceded photosynthesis, and this preceded respiration. It is also suggested that nonredox photoprocesses of the Halobacterium type are not part of the mainstream of bioenergetic evolution. They do not lead to photoprocesses with electron flow. (author)

  19. The Stromal Microenvironment Modulates Mitochondrial Oxidative Phosphorylation in Chronic Lymphocytic Leukemia Cells

    Directory of Open Access Journals (Sweden)

    Hima V. Vangapandu

    2017-10-01

    Full Text Available Peripheral blood chronic lymphocytic leukemia (CLL cells are replicationally quiescent mature B-cells. In short-term cultures, supporting stromal cells provide a survival advantage to CLL cells by inducing transcription and translation without promoting proliferation. We hypothesized that the stromal microenvironment augments malignant B cells' metabolism to enable the cells to cope with their energy demands for transcription and translation. We used extracellular flux analysis to assess the two major energy-generating pathways, mitochondrial oxidative phosphorylation (OxPhos and glycolysis, in primary CLL cells in the presence of three different stromal cell lines. OxPhos, measured as the basal oxygen consumption rate (OCR and maximum respiration capacity, was significantly higher in 28 patients' CLL cells cocultured with bone marrow–derived NK.Tert stromal cells than in CLL cells cultured alone (P = .004 and <.0001, respectively. Similar OCR induction was observed in CLL cells cocultured with M2-10B4 and HS-5 stromal lines. In contrast, heterogeneous changes in the extracellular acidification rate (a measure of glycolysis were observed in CLL cells cocultured with stromal cells. Ingenuity Pathway Analysis of CLL cells' metabolomics profile indicated stroma-mediated stimulation of nucleotide synthesis. Quantitation of ribonucleotide pools showed a significant two-fold increase in CLL cells cocultured with stromal cells, indicating that the stroma may induce CLL cellular bioenergy and the RNA building blocks necessary for the transcriptional requirement of a prosurvival phenotype. The stroma did not impact the proliferation index (Ki-67 staining of CLL cells. Collectively, these data suggest that short-term interaction (≤24 hours with stroma increases OxPhos and bioenergy in replicationally quiescent CLL cells.

  20. Respiration sensor made from indium tin oxide-coated conductive fabrics

    Science.gov (United States)

    Kim, Sun Hee; Lee, Joo Hyeon; Jee, Seung Hyun

    2015-02-01

    Conductive fabrics with new properties and applications have been the subject of extensive research over the last few years, with wearable respiration sensors attracting much attention. Different methods can be used to obtain fabrics that are electrically conducting, an essential property for various applications. For instance, fabrics can be coated with conductive polymers. Here, indium tin oxide (ITO)-coated conductive fabrics with cross-linked polyvinyl alcohol (C-PVA) were prepared using a doctor-blade. The C-PVA was employed in the synthesis to bind ITO on the fabrics with the highest possible mechanical strength. The feasibility of a respiration sensor prepared using the ITO-coated conductive fabric was investigated. The ITO-coated conductive fabric with the C-PVA was demonstrated to have a high potential for use in respiration sensors.

  1. The role of nitric oxide in muscle fibers with oxidative phosphorylation defects

    International Nuclear Information System (INIS)

    Tengan, Celia H.; Kiyomoto, Beatriz H.; Godinho, Rosely O.; Gamba, Juliana; Neves, Afonso C.; Schmidt, Beny; Oliveira, Acary S.B.; Gabbai, Alberto A.

    2007-01-01

    NO has been pointed as an important player in the control of mitochondrial respiration, especially because of its inhibitory effect on cytochrome c oxidase (COX). However, all the events involved in this control are still not completely elucidated. We demonstrate compartmentalized abnormalities on nitric oxide synthase (NOS) activity on muscle biopsies of patients with mitochondrial diseases. NOS activity was reduced in the sarcoplasmic compartment in COX deficient fibers, whereas increased activity was found in the sarcolemma of fibers with mitochondrial proliferation. We observed increased expression of neuronal NOS (nNOS) in patients and a correlation between nNOS expression and mitochondrial content. Treatment of skeletal muscle culture with an NO donor induced an increase in mitochondrial content. Our results indicate specific roles of NO in compensatory mechanisms of muscle fibers with mitochondrial deficiency and suggest the participation of nNOS in the signaling process of mitochondrial proliferation in human skeletal muscle

  2. Accurate determination of the oxidative phosphorylation affinity for ADP in isolated mitochondria.

    Directory of Open Access Journals (Sweden)

    Gilles Gouspillou

    Full Text Available BACKGROUND: Mitochondrial dysfunctions appear strongly implicated in a wide range of pathologies. Therefore, there is a growing need in the determination of the normal and pathological integrated response of oxidative phosphorylation to cellular ATP demand. The present study intends to address this issue by providing a method to investigate mitochondrial oxidative phosphorylation affinity for ADP in isolated mitochondria. METHODOLOGY/PRINCIPAL FINDINGS: The proposed method is based on the simultaneous monitoring of substrate oxidation (determined polarographically and phosphorylation (determined using the glucose-hexokinase glucose-6-phosphate dehydrogenase-NADP(+ enzymatic system rates, coupled to the determination of actual ADP and ATP concentrations by bioluminescent assay. This enzymatic system allows the study of oxidative phosphorylation during true steady states in a wide range of ADP concentrations. We demonstrate how the application of this method allows an accurate determination of mitochondrial affinity for ADP from both oxidation (K(mVox and phosphorylation (K(mVp rates. We also demonstrate that determination of K(mVox leads to an important overestimation of the mitochondrial affinity for ADP, indicating that mitochondrial affinity for ADP should be determined using phosphorylation rate. Finally, we show how this method allows the direct and precise determination of the mitochondrial coupling efficiency. Data obtained from rat skeletal muscle and liver mitochondria illustrate the discriminating capabilities of this method. CONCLUSIONS/SIGNIFICANCE: Because the proposed method allows the accurate determination of mitochondrial oxidative phosphorylation affinity for ADP in isolated mitochondria, it also opens the route to a better understanding of functional consequences of mitochondrial adaptations/dysfunctions arising in various physiological/pathophysiological conditions.

  3. Tyrosine phosphorylation in T cells is regulated by phosphatase activity: studies with phenylarsine oxide.

    OpenAIRE

    Garcia-Morales, P; Minami, Y; Luong, E; Klausner, R D; Samelson, L E

    1990-01-01

    Activation of T cells induces rapid tyrosine phosphorylation on the T-cell receptor zeta chain and other substrates. These phosphorylations can be regulated by a number of protein-tyrosine kinases (ATP: protein-tyrosine O-phosphotransferase, EC 2.7.1.112) and protein-tyrosine-phosphatases (protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48). In this study, we demonstrate that phenylarsine oxide can inhibit tyrosine phosphatases while leaving tyrosine kinase function intact. We use this ...

  4. Effects of ionization and nitrous oxide on grated carrot respiration

    International Nuclear Information System (INIS)

    Chervin, C.

    1992-06-01

    Two treatments (nitrous oxide and irradiation) have been applied on grated carrots to reduce the respiratory crisis induced by wounding. Nitrous oxide inhibited cytochrome c oxidase; but, it neither diminished O 2 consumption of the tissues, nor modified atmospheres in a favourable way for conservation of grated carrots, stored in plastic bags (in the conditions chosen for this study). On the contrary, irradiation inhibited simultaneously the respiratory crisis and the ethylene production, both induced by wounding. This behaviour led to a lower consumption of sugars in irradiated tissues and to the generation of atmospheres, which were better adapted to the conservation needs (it was necessary to use plastic film with high permeability). Finally, an applied study demonstrated that irradiation, by permitting a less denaturing preparation than industrial process, allowed the conservation of produces with a better quality (nutritional, sensory and microbiological). Biochemical analyses have been validated by sensory analyses

  5. Protein kinase A governs oxidative phosphorylation kinetics and oxidant emitting potential at complex I

    Directory of Open Access Journals (Sweden)

    Daniel Stephen Lark

    2015-11-01

    Full Text Available The mitochondrial electron transport system (ETS is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC/cyclic AMP (cAMP/Protein kinase A (PKA axis, has recently been revealed as a potential mechanism regulating the ETS. However, the governance of cAMP/PKA signaling and its implications on ETS function are incompletely understood. In contrast to prior reports using exogenous bicarbonate, we provide evidence that endogenous CO2 produced by increased tricarboxylic acid (TCA cycle flux is insufficient to increase mitochondrial cAMP levels, and that exogenous addition of membrane permeant 8Br-cAMP does not enhance mitochondrial respiratory capacity. We also report important non-specific effects of commonly used inhibitors of sAC which preclude their use in studies of mitochondrial function. In isolated liver mitochondria, inhibition of PKA reduces complex I-, but not complex II-supported respiratory capacity. In permeabilized myofibers, inhibition of PKA lowers both the Km and Vmax for complex I-supported respiration as well as succinate-supported H2O2 emitting potential. In summary, the data provided here improve our understanding of how mitochondrial cAMP production is regulated, illustrate a need for better tools to examine the impact of sAC activity on mitochondrial biology, and suggest that cAMP/PKA signaling contributes to the governance of electron flow through complex I of the ETS.

  6. Mitochondrial oxidative phosphorylation efficiency is upregulated during fasting in two major oxidative tissues of ducklings.

    Science.gov (United States)

    Monternier, Pierre-Axel; Teulier, Loïc; Drai, Jocelyne; Bourguignon, Aurore; Collin-Chavagnac, Delphine; Hervant, Frédéric; Rouanet, Jean-Louis; Roussel, Damien

    2017-10-01

    Fasted endothermic vertebrates must develop physiological responses to maximize energy conservation and survival. The aim of this study was to determine the effect of 1-wk. fasting in 5-wk. old ducklings (Cairina moschata) from whole-body resting metabolic rate and body temperature to metabolic phenotype of tissues and mitochondrial coupling efficiency. At the level of whole organism, the mass-specific metabolic rate of ducklings was decreased by 40% after 1-wk. of fasting, which was associated with nocturnal Tb declines and shallow diurnal hypothermia during fasting. At the cellular level, fasting induced a large reduction in liver, gastrocnemius (oxidative) and pectoralis (glycolytic) muscle masses together with a fuel selection towards lipid oxidation and ketone body production in liver and a lower glycolytic phenotype in skeletal muscles. At the level of mitochondria, fasting induced a reduction of oxidative phosphorylation activities and an up-regulation of coupling efficiency (+30% on average) in liver and skeletal muscles. The present integrative study shows that energy conservation in fasted ducklings is mainly achieved by an overall reduction in mitochondrial activity and an increase in mitochondrial coupling efficiency, which would, in association with shallow hypothermia, increase the conservation of endogenous fuel stores during fasting. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Ecosystem respiration, methane and nitrous oxide fluxes from ecotopes in a rewetted extracted peatland in Sweden

    Directory of Open Access Journals (Sweden)

    S. Jordan

    2016-09-01

    Full Text Available Ecosystem respiration (carbon dioxide; CO2, methane (CH4 and nitrous oxide (N2O fluxes to the atmosphere were determined using an opaque closed chamber method within various ecotopes (vegetation covered, bare peat and open water in a rewetted extracted peatland and within an adjacent open poor fen in Sweden. Ecotopes had a significant impact on CO2 and CH4 fluxes to the atmosphere. Ecosystem respiration and CH4 emissions from the bare peat site, the constructed shallow lake and the open poor fen were low but were much higher from ecotopes with Eriophorum vaginatum tussocks and Eriophorum angustifolium. A combination of vascular plant cover and high soil temperatures enhanced ecosystem respiration, while a combination of vascular plant cover, high water table levels and high soil temperatures enhanced CH4 emissions. N2O emissions contributed little to total greenhouse gas (GHG fluxes from the soil-plant-water systems to the atmosphere. However, the overall climate impact of CH4 emissions from the study area did not exceed the impact of soil and plant respiration. With regard to management of extracted peatlands, the construction of a nutrient-poor shallow lake showed great potential for lowering GHG fluxes to the atmosphere.

  8. Rethinking anaerobic As(III) oxidation in filters: Effect of indigenous nitrate respirers.

    Science.gov (United States)

    Cui, Jinli; Du, Jingjing; Tian, Haixia; Chan, Tingshan; Jing, Chuanyong

    2018-04-01

    Microorganisms play a key role in the redox transformation of arsenic (As) in aquifers. In this study, the impact of indigenous bacteria, especially the prevailing nitrate respirers, on arsenite (As(III)) oxidation was explored during groundwater filtration using granular TiO 2 and subsequent spent TiO 2 anaerobic landfill. X-ray absorption near edge structure spectroscopy analysis showed As(III) oxidation (46% in 10 days) in the presence of nitrate in the simulated anaerobic landfills. Meanwhile, iron (Fe) species on the spent TiO 2 were dominated by amorphous ferric arsenate, ferrihydrite and goethite. The Fe phase showed no change during the anaerobic landfill incubation. Batch incubation experiments implied that the indigenous bacteria completely oxidized As(III) to arsenate (As(V)) in 10 days using nitrate as the terminal electron acceptor under anaerobic conditions. The bacterial community analysis indicated that various kinds of microbial species exist in groundwater matrix. Phylogenetic tree analysis revealed that Proteobacteria was the dominant phylum, with Hydrogenophaga (34%), Limnohabitans (16%), and Simplicispira (7%) as the major bacterial genera. The nitrate respirers especially from the Hydrogenophaga genus anaerobically oxidized As(III) using nitrate as an electron acceptor instead of oxygen. Our study implied that microbes can facilitate the groundwater As oxidation using nitrate on the adsorptive media. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and Caucasians in the arctic winter.

    Science.gov (United States)

    Gnaiger, E; Boushel, R; Søndergaard, H; Munch-Andersen, T; Damsgaard, R; Hagen, C; Díez-Sánchez, C; Ara, I; Wright-Paradis, C; Schrauwen, P; Hesselink, M; Calbet, J A L; Christiansen, M; Helge, J W; Saltin, B

    2015-12-01

    During evolution, mitochondrial DNA haplogroups of arctic populations may have been selected for lower coupling of mitochondrial respiration to ATP production in favor of higher heat production. We show that mitochondrial coupling in skeletal muscle of traditional and westernized Inuit habituating northern Greenland is identical to Danes of western Europe haplogroups. Biochemical coupling efficiency was preserved across variations in diet, muscle fiber type, and uncoupling protein-3 content. Mitochondrial phenotype displayed plasticity in relation to lifestyle and environment. Untrained Inuit and Danes had identical capacities to oxidize fat substrate in arm muscle, which increased in Danes during the 42 days of acclimation to exercise, approaching the higher level of the Inuit hunters. A common pattern emerges of mitochondrial acclimatization and evolutionary adaptation in humans at high latitude and high altitude where economy of locomotion may be optimized by preservation of biochemical coupling efficiency at modest mitochondrial density, when submaximum performance is uncoupled from VO2max and maximum capacities of oxidative phosphorylation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Calcium Co-regulates Oxidative Metabolism and ATP Synthase-dependent Respiration in Pancreatic Beta Cells

    Science.gov (United States)

    De Marchi, Umberto; Thevenet, Jonathan; Hermant, Aurelie; Dioum, Elhadji; Wiederkehr, Andreas

    2014-01-01

    Mitochondrial energy metabolism is essential for glucose-induced calcium signaling and, therefore, insulin granule exocytosis in pancreatic beta cells. Calcium signals are sensed by mitochondria acting in concert with mitochondrial substrates for the full activation of the organelle. Here we have studied glucose-induced calcium signaling and energy metabolism in INS-1E insulinoma cells and human islet beta cells. In insulin secreting cells a surprisingly large fraction of total respiration under resting conditions is ATP synthase-independent. We observe that ATP synthase-dependent respiration is markedly increased after glucose stimulation. Glucose also causes a very rapid elevation of oxidative metabolism as was followed by NAD(P)H autofluorescence. However, neither the rate of the glucose-induced increase nor the new steady-state NAD(P)H levels are significantly affected by calcium. Our findings challenge the current view, which has focused mainly on calcium-sensitive dehydrogenases as the target for the activation of mitochondrial energy metabolism. We propose a model of tight calcium-dependent regulation of oxidative metabolism and ATP synthase-dependent respiration in beta cell mitochondria. Coordinated activation of matrix dehydrogenases and respiratory chain activity by calcium allows the respiratory rate to change severalfold with only small or no alterations of the NAD(P)H/NAD(P)+ ratio. PMID:24554722

  11. Circles within circles: crosstalk between protein Ser/Thr/Tyr-phosphorylation and Met oxidation

    Science.gov (United States)

    Background: Reversible posttranslational protein modifications such as phosphorylation of Ser/Thr/Tyr and Met oxidation are critical for both metabolic regulation and cellular signalling. Although these modifications are typically studied individually, herein we describe the potential for cross-talk...

  12. Biological Significance of the Suppression of Oxidative Phosphorylation in Induced Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Cheng Zhang

    2017-11-01

    Full Text Available We discovered that induced pluripotent stem cell (iPSC clones generated from aged tissue donors (A-iPSCs fail to suppress oxidative phosphorylation. Compared to embryonic stem cells (ESCs and iPSCs generated from young donors (Y-iPSCs, A-iPSCs show poor expression of the pluripotent stem cell-specific glucose transporter 3 (GLUT3 and impaired glucose uptake, making them unable to support the high glucose demands of glycolysis. Persistent oxidative phosphorylation in A-iPSCs generates higher levels of reactive oxygen species (ROS, which leads to excessive elevation of glutathione (a ROS-scavenging metabolite and a blunted DNA damage response. These phenotypes were recapitulated in Y-iPSCs by inhibiting pyruvate dehydrogenase kinase (PDK or supplying citrate to activate oxidative phosphorylation. In addition, oxidative phosphorylation in A-iPSC clones depletes citrate, a nuclear source of acetyl group donors for histone acetylation; this consequently alters histone acetylation status. Expression of GLUT3 in A-iPSCs recovers the metabolic defect, DNA damage response, and histone acetylation status.

  13. IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION

    Science.gov (United States)

    IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION.T. L. Knuckles1 R. Jaskot2, J. Richards2, and K.Dreher2.1Department of Molecular and Biomedical Sciences, College of Veterinary Medicin...

  14. Evaluation of respiration in compost landfill biocovers intended for methane oxidation

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Pedicone, Alessio; Pedersen, Gitte Bukh

    2011-01-01

    A low-cost alternative approach to reduce landfill gas (LFG) emissions is to integrate compost into the landfill cover design in order to establish a biocover that is optimized for biological oxidation of methane (CH4). A laboratory and field investigation was performed to quantify respiration...... in an experimental compost biocover in terms of oxygen (O2) consumption and carbon dioxide (CO2) production and emission rates. O2 consumption and CO2 production rates were measured in batch and column experiments containing compost sampled from a landfill biowindow at Fakse landfill in Denmark. Column gas...... concentration profiles were compared to field measurements. Column studies simulating compost respiration in the biowindow showed average CO2 production and O2 consumption rates of 107±14gm−2d−1 and 63±12gm−2d−1, respectively. Gas profiles from the columns showed elevated CO2 concentrations throughout...

  15. Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation.

    Science.gov (United States)

    Sutton, Nora B; Atashgahi, Siavash; Saccenti, Edoardo; Grotenhuis, Tim; Smidt, Hauke; Rijnaarts, Huub H M

    2015-01-01

    While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose

  16. Ribosome-dependent ATPase interacts with conserved membrane protein in Escherichia coli to modulate protein synthesis and oxidative phosphorylation.

    Directory of Open Access Journals (Sweden)

    Mohan Babu

    Full Text Available Elongation factor RbbA is required for ATP-dependent deacyl-tRNA release presumably after each peptide bond formation; however, there is no information about the cellular role. Proteomic analysis in Escherichia coli revealed that RbbA reciprocally co-purified with a conserved inner membrane protein of unknown function, YhjD. Both proteins are also physically associated with the 30S ribosome and with members of the lipopolysaccharide transport machinery. Genome-wide genetic screens of rbbA and yhjD deletion mutants revealed aggravating genetic interactions with mutants deficient in the electron transport chain. Cells lacking both rbbA and yhjD exhibited reduced cell division, respiration and global protein synthesis as well as increased sensitivity to antibiotics targeting the ETC and the accuracy of protein synthesis. Our results suggest that RbbA appears to function together with YhjD as part of a regulatory network that impacts bacterial oxidative phosphorylation and translation efficiency.

  17. Fipronil is a powerful uncoupler of oxidative phosphorylation that triggers apoptosis in human neuronal cell line SHSY5Y.

    Science.gov (United States)

    Vidau, Cyril; González-Polo, Rosa A; Niso-Santano, Mireia; Gómez-Sánchez, Rubén; Bravo-San Pedro, José M; Pizarro-Estrella, Elisa; Blasco, Rafael; Brunet, Jean-Luc; Belzunces, Luc P; Fuentes, José M

    2011-12-01

    Fipronil is a phenylpyrazole insecticide known to elicit neurotoxicity via an interaction with ionotropic receptors, namely GABA and glutamate receptors. Recently, we showed that fipronil and other phenylpyrazole compounds trigger cell death in Caco-2 cells. In this study, we investigated the mode of action and the type of cell death induced by fipronil in SH-SY5Y human neuroblastoma cells. Flow cytometric and western blot analyses demonstrated that fipronil induces cellular events belonging to the apoptosis process, such as mitochondrial potential collapse, cytochrome c release, caspase-3 activation, nuclear condensation and phosphatidylserine externalization. In addition, fipronil induces a rapid ATP depletion with concomitant activation of anaerobic glycolysis. This cellular response is characteristic of mitochondrial injury associated with a defect of the respiration process. Therefore, we also investigated the effect of fipronil on the oxygen consumption in isolated mitochondria. Interestingly, we show for the first time that fipronil is a strong uncoupler of oxidative phosphorylation at relative low concentrations. Thus in this study, we report a new mode of action by which the insecticide fipronil could triggers apoptosis. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Lipid raft proteome reveals that oxidative phosphorylation system is associated with the plasma membrane.

    Science.gov (United States)

    Kim, Bong-Woo; Lee, Chang Seok; Yi, Jae-Sung; Lee, Joo-Hyung; Lee, Joong-Won; Choo, Hyo-Jung; Jung, Soon-Young; Kim, Min-Sik; Lee, Sang-Won; Lee, Myung-Shik; Yoon, Gyesoon; Ko, Young-Gyu

    2010-12-01

    Although accumulating proteomic analyses have supported the fact that mitochondrial oxidative phosphorylation (OXPHOS) complexes are localized in lipid rafts, which mediate cell signaling, immune response and host-pathogen interactions, there has been no in-depth study of the physiological functions of lipid-raft OXPHOS complexes. Here, we show that many subunits of OXPHOS complexes were identified from the lipid rafts of human adipocytes, C2C12 myotubes, Jurkat cells and surface biotin-labeled Jurkat cells via shotgun proteomic analysis. We discuss the findings of OXPHOS complexes in lipid rafts, the role of the surface ATP synthase complex as a receptor for various ligands and extracellular superoxide generation by plasma membrane oxidative phosphorylation complexes.

  19. BCL-2 inhibition targets oxidative phosphorylation and selectively eradicates quiescent human leukemia stem cells

    Science.gov (United States)

    Lagadinou, Eleni D.; Sach, Alexander; Callahan, Kevin; Rossi, Randall M.; Neering, Sarah J.; Minhajuddin, Mohammad; Ashton, John M.; Pei, Shanshan; Grose, Valerie; O’Dwyer, Kristen M.; Liesveld, Jane L.; Brookes, Paul S.; Becker, Michael W.; Jordan, Craig T.

    2013-01-01

    Summary Most forms of chemotherapy employ mechanisms involving induction of oxidative stress, a strategy that can be effective due to the elevated oxidative state commonly observed in cancer cells. However, recent studies have shown that relative redox levels in primary tumors can be heterogeneous, suggesting that regimens dependent on differential oxidative state may not be uniformly effective. To investigate this issue in hematological malignancies, we evaluated mechanisms controlling oxidative state in primary specimens derived from acute myelogenous leukemia (AML) patients. Our studies demonstrate three striking findings. First, the majority of functionally-defined leukemia stem cells (LSCs) are characterized by relatively low levels of reactive oxygen species (termed “ROS-low”). Second, ROS-low LSCs aberrantly over-express BCL-2. Third, BCL-2 inhibition reduced oxidative phosphorylation and selectively eradicated quiescent LSCs. Based on these findings, we propose a model wherein the unique physiology of ROS-low LSCs provides an opportunity for selective targeting via disruption of BCL-2-dependent oxidative phosphorylation. PMID:23333149

  20. Hepatic mitochondrial oxidative phosphorylation is normal in obese patients with and without type 2 diabetes

    DEFF Research Database (Denmark)

    Lund, Michael Taulo; Kristensen, Marianne Dalsgaard; Hansen, Merethe

    2016-01-01

    INTRODUCTION: Obese patients with (T2DM) and without (OB) type 2 diabetes are characterized by high hepatic lipid content and hepatic insulin resistance. This may be linked to impaired hepatic mitochondrial oxidative phosphorylation (OXPHOS) capacity. The aim of the present study was to investiga...... role in the development of obesity-induced type 2 diabetes. This article is protected by copyright. All rights reserved....

  1. Telmisartan activates endothelial nitric oxide synthase via Ser1177 phosphorylation in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Masahiro Myojo

    Full Text Available Because endothelial nitric oxide synthase (eNOS has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177 in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172 and eNOS and the concentration of intracellular guanosine 3',5'-cyclic monophosphate (cGMP. Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.

  2. Impaired cardiac mitochondrial oxidative phosphorylation and enhanced mitochondrial oxidative stress in feline hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Christiansen, Liselotte Bruun; Dela, Flemming; Koch, Jørgen

    2015-01-01

    respiration with complex I-linked nonfatty acid substrates and with fatty acid substrates, respectively, was significantly lower in the hearts of HCM cats compared with control cats. Mitochondrial ROS release during state 3 with complex I-linked substrates and thiobarbituric acid-reactive substances...

  3. Chlorogenic acid ameliorates endotoxin-induced liver injury by promoting mitochondrial oxidative phosphorylation

    International Nuclear Information System (INIS)

    Zhou, Yan; Ruan, Zheng; Zhou, Lili; Shu, Xugang; Sun, Xiaohong; Mi, Shumei; Yang, Yuhui; Yin, Yulong

    2016-01-01

    Acute or chronic hepatic injury is a common pathology worldwide. Mitochondrial dysfunction and the depletion of adenosine triphosphate (ATP) play important roles in liver injury. Chlorogenic acids (CGA) are some of the most abundant phenolic acids in human diet. This study was designed to test the hypothesis that CGA may protect against chronic lipopolysaccharide (LPS)-induced liver injury by modulating mitochondrial energy generation. CGA decreased the activities of serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase. The contents of ATP and adenosine monophosphate (AMP), as well as the ratio of AMP/ATP, were increased after CGA supplementation. The activities of enzymes that are involved in glycolysis were reduced, while those of enzymes involved in oxidative phosphorylation were increased. Moreover, phosphorylated AMP-activated protein kinase (AMPK), and mRNA levels of AMPK-α, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial DNA transcription factor A were increased after CGA supplementation. Collectively, these findings suggest that the hepatoprotective effect of CGA might be associated with enhanced ATP production, the stimulation of mitochondrial oxidative phosphorylation and the inhibition of glycolysis. - Highlights: • Dietary supplementation with chlorogenic acid (CGA) improved endotoxin-induced liver injury. • Chlorogenic acid enhances ATP increase and shifts energy metabolism, which is correlated with up-regulation AMPK and PGC-1α. • The possible mechanism of CGA on mitochondrial biogenesis was correlated with up-regulation AMPK and PGC-1α.

  4. Chlorogenic acid ameliorates endotoxin-induced liver injury by promoting mitochondrial oxidative phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yan [State Key Laboratory of Food Science and Technology and School of Food Science, Nanchang University, Nanchang 330047 (China); College of Food Safety, Guizhou Medical University, Guiyang 550025 (China); Ruan, Zheng, E-mail: ruanzheng@ncu.edu.cn [State Key Laboratory of Food Science and Technology and School of Food Science, Nanchang University, Nanchang 330047 (China); Zhou, Lili; Shu, Xugang [State Key Laboratory of Food Science and Technology and School of Food Science, Nanchang University, Nanchang 330047 (China); Sun, Xiaohong [College of Food Safety, Guizhou Medical University, Guiyang 550025 (China); Mi, Shumei; Yang, Yuhui [State Key Laboratory of Food Science and Technology and School of Food Science, Nanchang University, Nanchang 330047 (China); Yin, Yulong, E-mail: yinyulong@isa.ac.cn [State Key Laboratory of Food Science and Technology and School of Food Science, Nanchang University, Nanchang 330047 (China); Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China)

    2016-01-22

    Acute or chronic hepatic injury is a common pathology worldwide. Mitochondrial dysfunction and the depletion of adenosine triphosphate (ATP) play important roles in liver injury. Chlorogenic acids (CGA) are some of the most abundant phenolic acids in human diet. This study was designed to test the hypothesis that CGA may protect against chronic lipopolysaccharide (LPS)-induced liver injury by modulating mitochondrial energy generation. CGA decreased the activities of serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase. The contents of ATP and adenosine monophosphate (AMP), as well as the ratio of AMP/ATP, were increased after CGA supplementation. The activities of enzymes that are involved in glycolysis were reduced, while those of enzymes involved in oxidative phosphorylation were increased. Moreover, phosphorylated AMP-activated protein kinase (AMPK), and mRNA levels of AMPK-α, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial DNA transcription factor A were increased after CGA supplementation. Collectively, these findings suggest that the hepatoprotective effect of CGA might be associated with enhanced ATP production, the stimulation of mitochondrial oxidative phosphorylation and the inhibition of glycolysis. - Highlights: • Dietary supplementation with chlorogenic acid (CGA) improved endotoxin-induced liver injury. • Chlorogenic acid enhances ATP increase and shifts energy metabolism, which is correlated with up-regulation AMPK and PGC-1α. • The possible mechanism of CGA on mitochondrial biogenesis was correlated with up-regulation AMPK and PGC-1α.

  5. Nitric oxide partitioning into mitochondrial membranes and the control of respiration at cytochrome c oxidase

    Science.gov (United States)

    Shiva, Sruti; Brookes, Paul S.; Patel, Rakesh P.; Anderson, Peter G.; Darley-Usmar, Victor M.

    2001-06-01

    An emerging and important site of action for nitric oxide (NO) within cells is the mitochondrial inner membrane, where NO binds to and inhibits members of the electron transport chain, complex III and cytochrome c oxidase. Although it is known that inhibition of cytochrome c oxidase by NO is competitive with O2, the mechanisms that underlie this phenomenon remain unclear, and the impact of both NO and O2 partitioning into biological membranes has not been considered. These properties are particularly interesting because physiological O2 tensions can vary widely, with NO having a greater inhibitory effect at low O2 tensions (mitochondrial membranes in the absence of substrate, in a nonsaturable process that is O2 dependent. This consumption modulates inhibition of cytochrome c oxidase by NO and is enhanced by the addition of exogenous membranes. From these data, it is evident that the partition of NO into mitochondrial membranes has a major impact on the ability of NO to control mitochondrial respiration. The implications of this conclusion are discussed in the context of mitochondrial lipid:protein ratios and the importance of NO as a regulator of respiration in pathophysiology.

  6. Effects of Anthropogenic Pollution on the Oxidative Phosphorylation Pathway of Hepatocytes from Natural Populations of Fundulus heteroclitus

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xiao; Crawford, Douglas L.; Oleksiak, Marjorie F., E-mail: moleksiak@rsmas.miami.edu

    2015-08-15

    Highlights: • Fish from a highly polluted and clean reference population were compared. • Oxidative phosphorylation (e.g., State 3, enzymes, and proton LEAK) was quantified. • Polluted fish had lower LEAK, enzyme III and enzyme IV but higher enzyme I. • Exposures to PAH and PCB only affected individuals from the reference population. - Abstract: Persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), potentially target mitochondria and cause toxicity. We compared the effects of POPs on mitochondrial respiration by measuring oxidative phosphorylation (OxPhos) metabolism in hepatocytes isolated from lab-depurated Fundulus heteroclitus from a Superfund site contaminated with PAHs (Elizabeth River VA, USA) relative to OxPhos metabolism in individuals from a relatively clean, reference population (King’s Creek VA, USA). In individuals from the polluted Elizabeth River population, OxPhos metabolism displayed lower LEAK and lower activities in complex III, complex IV, and E State, but higher activity in complex I compared to individuals from the reference King’s Creek population. To test the supposition that these differences were due to or related to the chronic PAH contamination history of the Elizabeth River population, we compared the OxPhos functions of undosed individuals from the polluted and reference populations to individuals from these populations dosed with a PAH {benzo [α] pyrene (BaP)} or a PCB {PCB126 (3,3′,4,4′,5-pentachlorobiphenyl)}, respectively. Exposure to PAH or PCB affected OxPhos in the reference King’s Creek population but had no detectable effects on the polluted Elizabeth River population. Thus, PAH exposure significantly increased LEAK, and exposure to PCB126 significantly decreased State 3, E state and complex I activity in the reference King’s Creek population. These data strongly implicate an evolved tolerance in the Elizabeth River fish where dosed

  7. Effects of Anthropogenic Pollution on the Oxidative Phosphorylation Pathway of Hepatocytes from Natural Populations of Fundulus heteroclitus

    International Nuclear Information System (INIS)

    Du, Xiao; Crawford, Douglas L.; Oleksiak, Marjorie F.

    2015-01-01

    Highlights: • Fish from a highly polluted and clean reference population were compared. • Oxidative phosphorylation (e.g., State 3, enzymes, and proton LEAK) was quantified. • Polluted fish had lower LEAK, enzyme III and enzyme IV but higher enzyme I. • Exposures to PAH and PCB only affected individuals from the reference population. - Abstract: Persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), potentially target mitochondria and cause toxicity. We compared the effects of POPs on mitochondrial respiration by measuring oxidative phosphorylation (OxPhos) metabolism in hepatocytes isolated from lab-depurated Fundulus heteroclitus from a Superfund site contaminated with PAHs (Elizabeth River VA, USA) relative to OxPhos metabolism in individuals from a relatively clean, reference population (King’s Creek VA, USA). In individuals from the polluted Elizabeth River population, OxPhos metabolism displayed lower LEAK and lower activities in complex III, complex IV, and E State, but higher activity in complex I compared to individuals from the reference King’s Creek population. To test the supposition that these differences were due to or related to the chronic PAH contamination history of the Elizabeth River population, we compared the OxPhos functions of undosed individuals from the polluted and reference populations to individuals from these populations dosed with a PAH {benzo [α] pyrene (BaP)} or a PCB {PCB126 (3,3′,4,4′,5-pentachlorobiphenyl)}, respectively. Exposure to PAH or PCB affected OxPhos in the reference King’s Creek population but had no detectable effects on the polluted Elizabeth River population. Thus, PAH exposure significantly increased LEAK, and exposure to PCB126 significantly decreased State 3, E state and complex I activity in the reference King’s Creek population. These data strongly implicate an evolved tolerance in the Elizabeth River fish where dosed

  8. Factors influencing radiation-induced impairment of rat liver mitochondrial oxidative phosphorylation

    International Nuclear Information System (INIS)

    Alexander, K.C.; Aiyar, A.S.; Sreenivasan, A.

    1975-01-01

    The influence of some experimental conditions on the radiation-induced impairment of oxidative phosphorylation in rat liver mitochondria has been studied. Shielding of the liver during whole body irradiation of the animal does not significantly alter the decreased efficiency of phosphorylation. There exists a great disparity in the in vivo and in vitro radiation doses required for the manifestation of damage to liver mitochondria. While these observations point to the abscopal nature of the radiation effects, direct involvement of the adrenals has been ruled out by studies with adrenalectomised rats. Prior administration of the well known radio-protective agents, serotonin or 2-aminoethyl isothiouronium bromide hydrobromide, is effective in preventing the derangement of mitochondrial function following radioexposure. The hypocholesterolemic drug ethyl-α-p-chlorophenoxy isobutyrate, which is known to influence hepatic mitochondrial turnover, does not afford any significant protection against either mitochondrial damage or the mortality of the animals due to whole body irradiation. (author)

  9. A comprehensive protein-protein interactome for yeast PAS kinase 1 reveals direct inhibition of respiration through the phosphorylation of Cbf1.

    Science.gov (United States)

    DeMille, Desiree; Bikman, Benjamin T; Mathis, Andrew D; Prince, John T; Mackay, Jordan T; Sowa, Steven W; Hall, Tacie D; Grose, Julianne H

    2014-07-15

    Per-Arnt-Sim (PAS) kinase is a sensory protein kinase required for glucose homeostasis in yeast, mice, and humans, yet little is known about the molecular mechanisms of its function. Using both yeast two-hybrid and copurification approaches, we identified the protein-protein interactome for yeast PAS kinase 1 (Psk1), revealing 93 novel putative protein binding partners. Several of the Psk1 binding partners expand the role of PAS kinase in glucose homeostasis, including new pathways involved in mitochondrial metabolism. In addition, the interactome suggests novel roles for PAS kinase in cell growth (gene/protein expression, replication/cell division, and protein modification and degradation), vacuole function, and stress tolerance. In vitro kinase studies using a subset of 25 of these binding partners identified Mot3, Zds1, Utr1, and Cbf1 as substrates. Further evidence is provided for the in vivo phosphorylation of Cbf1 at T211/T212 and for the subsequent inhibition of respiration. This respiratory role of PAS kinase is consistent with the reported hypermetabolism of PAS kinase-deficient mice, identifying a possible molecular mechanism and solidifying the evolutionary importance of PAS kinase in the regulation of glucose homeostasis. © 2014 DeMille et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  10. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?

    Science.gov (United States)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I; Trinity, Joel D; Hyngstrom, John R; Garten, Ryan S; Diakos, Nikolaos A; Ives, Stephen J; Dela, Flemming; Larsen, Steen; Drakos, Stavros; Richardson, Russell S

    2014-08-01

    Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 ± 1, 39 ± 4, and 15 ± 1 pmol·s(-1)·mg(-1), P respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 ± 0.7, 3.2 ± 0.4, and 1.6 ± 0.3 pmol·s(-1)·mg(-1), P respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.

  11. [Features of noradrenaline stimulation of rat liver mitochondria respiration by ADP and calcium ions].

    Science.gov (United States)

    Stefankiv, Iu S; Babskyĭ, A M; Shostakovska, Y V

    1995-01-01

    A single administration of a physiological dose of noradrenaline to animals. in contrast to adrenaline, stimulates the respiration of mitochondria not only under oxidation of FAD-dependent Krebbs cycle substrate of the succinase but also HAD-dependent substrate of alpha-ketoglutarate. In the both cases the phosphorylation rate increases, since the action of noradrenaline, separating the respiration and oxidative phosphorylation, was not found. Noradrenaline increases the capacity of mitochondria to more actively absorb calcium ions under oxidation of succinate than under that of alpha-ketoglutarate.

  12. Oxidative phosphorylation in a thermophilic, facultative chemoautotroph, Hydrogenophilus thermoluteolus, living prevalently in geothermal niches.

    Science.gov (United States)

    Wakai, Satoshi; Masanari, Misa; Ikeda, Takumi; Yamaguchi, Naho; Ueshima, Saori; Watanabe, Kaori; Nishihara, Hirofumi; Sambongi, Yoshihiro

    2013-04-01

    Hydrogenophilus is a thermophilic, facultative chemoautotroph, which lives prevalently in high temperature geothermal niches. Despite the environmental distribution, little is known about its oxidative phosphorylation. Here, we show that inverted membrane vesicles derived from Hydrogenophilus thermoluteolus cells autotrophically cultivated with H2 formed a proton gradient on the addition of succinate, dl-lactate, and NADH, and exhibited oxidation activity toward these three organic compounds. These indicate the capability of mixotrophic growth of this bacterium. Biochemical analysis demonstrated that the same vesicles contained an F-type ATP synthase. The F1 sector of the ATP synthase purified from H. thermoluteolus membranes exhibited optimal ATPase activity at 65°C. Transformed Escherichia coli membranes expressing H. thermoluteolus F-type ATP synthase exhibited the same temperature optimum for the ATPase. These findings shed light on H. thermoluteolus oxidative phosphorylation from the aspects of membrane bioenergetics and ATPase biochemistry, which must be fundamental and advantageous in the biogeochemical cycles occurred in the high temperature geothermal niches. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. A novel mechanism involved in the coupling of mitochondrial biogenesis to oxidative phosphorylation

    Directory of Open Access Journals (Sweden)

    Jelena Ostojić

    2014-01-01

    Full Text Available Mitochondria are essential organelles that are central to a multitude of cellular processes, including oxidative phosphorylation (OXPHOS, which produces most of the ATP in animal cells. Thus it is important to understand not only the mechanisms and biogenesis of this energy production machinery but also how it is regulated in both physiological and pathological contexts. A recent study by Ostojić et al. [Cell Metabolism (2013 18, 567-577] has uncovered a regulatory loop by which the biogenesis of a major enzyme of the OXPHOS pathway, the respiratory complex III, is coupled to the energy producing activity of the mitochondria.

  14. Uncoupling of oxidative phosphorylation by curcumin: Implication of its cellular mechanism of action

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Han Wern; Lim, Hwee Ying [Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119260 (Singapore); Wong, Kim Ping, E-mail: bchsitkp@nus.edu.sg [Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119260 (Singapore)

    2009-11-06

    Curcumin is a phytochemical isolated from the rhizome of turmeric. Recent reports have shown curcumin to have antioxidant, anti-inflammatory and anti-tumor properties as well as affecting the 5'-AMP activated protein kinase (AMPK), mTOR and STAT-3 signaling pathways. We provide evidence that curcumin acts as an uncoupler. Well-established biochemical techniques were performed on isolated rat liver mitochondria in measuring oxygen consumption, F{sub 0}F{sub 1}-ATPase activity and ATP biosynthesis. Curcumin displays all the characteristics typical of classical uncouplers like fccP and 2,4-dinitrophenol. In addition, at concentrations higher than 50 {mu}M, curcumin was found to inhibit mitochondrial respiration which is a characteristic feature of inhibitory uncouplers. As a protonophoric uncoupler and as an activator of F{sub 0}F{sub 1}-ATPase, curcumin causes a decrease in ATP biosynthesis in rat liver mitochondria. The resulting change in ATP:AMP could disrupt the phosphorylation status of the cell; this provides a possible mechanism for its activation of AMPK and its downstream mTOR and STAT-3 signaling.

  15. Uncoupling of oxidative phosphorylation by curcumin: Implication of its cellular mechanism of action

    International Nuclear Information System (INIS)

    Lim, Han Wern; Lim, Hwee Ying; Wong, Kim Ping

    2009-01-01

    Curcumin is a phytochemical isolated from the rhizome of turmeric. Recent reports have shown curcumin to have antioxidant, anti-inflammatory and anti-tumor properties as well as affecting the 5'-AMP activated protein kinase (AMPK), mTOR and STAT-3 signaling pathways. We provide evidence that curcumin acts as an uncoupler. Well-established biochemical techniques were performed on isolated rat liver mitochondria in measuring oxygen consumption, F 0 F 1 -ATPase activity and ATP biosynthesis. Curcumin displays all the characteristics typical of classical uncouplers like fccP and 2,4-dinitrophenol. In addition, at concentrations higher than 50 μM, curcumin was found to inhibit mitochondrial respiration which is a characteristic feature of inhibitory uncouplers. As a protonophoric uncoupler and as an activator of F 0 F 1 -ATPase, curcumin causes a decrease in ATP biosynthesis in rat liver mitochondria. The resulting change in ATP:AMP could disrupt the phosphorylation status of the cell; this provides a possible mechanism for its activation of AMPK and its downstream mTOR and STAT-3 signaling.

  16. Hydrocortisone and insulin effect on oxidative phosphorylation in mitochondria of liver and spleen th rats exposed to fast neutrons

    International Nuclear Information System (INIS)

    Sutkovoj, D.A.; Alferov, A.N.; Letov, V.N.

    1979-01-01

    Total-body exposure of rats to fast neutrons (100 rad) elicits an increase in the content of 11-oxycorticosteroids in blood plasma and an appreciable decrease in the respiratory and phosphorylation activity of liver and spleen mitochondria. Administration of hydrocortisone (50 mg/kg) and particularly insulin (2 units/kg) intensifies energy generation in the liver. In the spleen, a beneficial effect was only produced by insulin. Glucocorticoid considerably aggravates the postradiation impairment of oxidative phosphorylation

  17. CNTF-ACM promotes mitochondrial respiration and oxidative stress in cortical neurons through upregulating L-type calcium channel activity.

    Science.gov (United States)

    Sun, Meiqun; Liu, Hongli; Xu, Huanbai; Wang, Hongtao; Wang, Xiaojing

    2016-09-01

    A specialized culture medium termed ciliary neurotrophic factor-treated astrocyte-conditioned medium (CNTF-ACM) allows investigators to assess the peripheral effects of CNTF-induced activated astrocytes upon cultured neurons. CNTF-ACM has been shown to upregulate neuronal L-type calcium channel current activity, which has been previously linked to changes in mitochondrial respiration and oxidative stress. Therefore, the aim of this study was to evaluate CNTF-ACM's effects upon mitochondrial respiration and oxidative stress in rat cortical neurons. Cortical neurons, CNTF-ACM, and untreated control astrocyte-conditioned medium (UC-ACM) were prepared from neonatal Sprague-Dawley rat cortical tissue. Neurons were cultured in either CNTF-ACM or UC-ACM for a 48-h period. Changes in the following parameters before and after treatment with the L-type calcium channel blocker isradipine were assessed: (i) intracellular calcium levels, (ii) mitochondrial membrane potential (ΔΨm), (iii) oxygen consumption rate (OCR) and adenosine triphosphate (ATP) formation, (iv) intracellular nitric oxide (NO) levels, (v) mitochondrial reactive oxygen species (ROS) production, and (vi) susceptibility to the mitochondrial complex I toxin rotenone. CNTF-ACM neurons displayed the following significant changes relative to UC-ACM neurons: (i) increased intracellular calcium levels (p ACM (p ACM promotes mitochondrial respiration and oxidative stress in cortical neurons through elevating L-type calcium channel activity.

  18. Expression of oxidative phosphorylation components in mitochondria of long-living Ames dwarf mice.

    Science.gov (United States)

    Brown-Borg, Holly M; Johnson, W Thomas; Rakoczy, Sharlene G

    2012-02-01

    Reduced signaling of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) pathway is associated with extended life span in several species. Ames dwarf mice are GH-deficient and live >50% longer than wild-type littermates. Previously, we have shown that tissues from Ames mice exhibit elevated levels of antioxidative enzymes, less H(2)O(2) production, and lower oxidative damage suggesting that mitochondrial function may differ between genotypes. To explore the relationship between hormone deficiency and mitochondria in mice with extended longevity, we evaluated activity, protein, and gene expression of oxidative phosphorylation components in dwarf and wild-type mice at varying ages. Liver complex I + III activity was higher in dwarf mice compared to wild-type mice. The activity of I + III decreased between 3 and 20 months of age in both genotypes with greater declines in wild-type mice in liver and skeletal muscle. Complex IV activities in the kidney were elevated in 3- and 20-month-old dwarf mice relative to wild-type mice. In Ames mice, protein levels of the 39 kDa complex I subunit were elevated at 20 months of age when compared to wild-type mouse mitochondria for every tissue examined. Kidney and liver mitochondria from 20-month-old dwarf mice had elevated levels of both mitochondrially-encoded and nuclear-encoded complex IV proteins compared to wild-type mice (p dwarf mice. Overall, we found that several components of the oxidative phosphorylation (OXPHOS) system were elevated in Ames mice. Mitochondrial to nuclear DNA ratios were not different between genotypes despite the marked increase in PGC-1α levels in dwarf mice. The increased OXPHOS activities, along with lower ROS production in dwarf mice, predict enhanced mitochondrial function and efficiency, two factors likely contributing to long-life in Ames mice.

  19. Comparison of physical chemical properties of powders and respirable aerosols of industrial mixed uranium and plutonium oxide fuels

    International Nuclear Information System (INIS)

    Eidson, A.F.

    1982-01-01

    Studies were performed to characterize physical and chemical properties which may be important in determining the metabolism of accidentally released, inhaled aerosols of industrial mixed uranium and plutonium oxide fuels and to compare the properties of bulk powders and the respirable fraction they include. X-ray diffraction measurements showed that analysis of mixed-oxide powders from four process steps served to characterize their respirable fractions. IR spectroscopy was useful as a method to detect organic binders that were not observed by X-ray diffraction methods. Both X-ray diffraction and IR spectroscopy methods can be used in combination to identify the sources of a complex aerosol that might be released from more than one fabrication step. Isotopic distributions in powders and aerosols showed that information important for radiation dose to tissue calculations or Pu lung burden estimates can be obtained by analysis of powders. (U.K.)

  20. Ferroxitosis: A cell death from modulation of oxidative phosphorylation and PKM2-dependent glycolysis in melanoma

    Science.gov (United States)

    Lakhter, Alexander J.; Hamilton, James; Dagher, Pierre C.; Mukkamala, Suresh; Hato, Takashi; Dong, X. Charlie; Mayo, Lindsey D.; Harris, Robert A.; Shekhar, Anantha; Ivan, Mircea; Brustovetsky, Nickolay; Naidu, Samisubbu R.

    2014-01-01

    Reliance on glycolysis is a characteristic of malignancy, yet the development of resistance to BRAF inhibitors in melanoma is associated with gain of mitochondrial function. Concurrent attenuation of oxidative phosphorylation and HIF-1α/PKM2-dependent glycolysis promotes a non-apoptotic, iron- and oxygen-dependent cell death that we term ferroxitosis. The redox cycling agent menadione causes a robust increase in oxygen consumption, accompanied by significant loss of intracellular ATP and rapid cell death. Conversely, either hypoxic adaptation or iron chelation prevents menadione-induced ferroxitosis. Ectopic expression of K213Q HIF-1α mutant blunts the effects of menadione. However, knockdown of HIF-1α or PKM2 restores menadione-induced cytotoxicity in hypoxia. Similarly, exposure of melanoma cells to shikonin, a menadione analog and a potential PKM2 inhibitor, is sufficient to induce ferroxitosis under hypoxic conditions. Collectively, our findings reveal that ferroxitosis curtails metabolic plasticity in melanoma. PMID:25587028

  1. Reliability of maximal mitochondrial oxidative phosphorylation in permeabilized fibers from the vastus lateralis employing high-resolution respirometry

    DEFF Research Database (Denmark)

    Cardinale, Daniele A; Gejl, Kasper D; Ørtenblad, Niels

    2018-01-01

    The purpose was to assess the impact of various factors on methodological errors associated with measurement of maximal oxidative phosphorylation (OXPHOS) in human skeletal muscle determined by high-resolution respirometry in saponin-permeabilized fibers. Biopsies were collected from 25 men...

  2. 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.

  3. 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.

  4. The active site of oxidative phosphorylation and the origin of hyperhomocysteinemia in aging and dementia.

    Science.gov (United States)

    McCully, Kilmer S

    2015-01-01

    The active site of oxidative phosphorylation and adenosine triphosphate (ATP) synthesis in mitochondria is proposed to consist of two molecules of thioretinamide bound to cobalamin, forming thioretinaco, complexed with ozone, oxygen, nicotinamide adenine dinucleotide. and inorganic phosphate, TR2CoO3O2NAD(+)H2PO4(-). Reduction of the pyridinium nitrogen of the nicotinamide group by an electron from electron transport complexes initiates polymerization of phosphate with adenosine diphosphate, yielding nicotinamide riboside and ATP bound to thioretinaco ozonide oxygen. A second electron reduces oxygen to hydroperoxyl radical, releasing ATP from the active site. A proton gradient is created within F1F0 ATPase complexes of mitochondria by reaction of protons with reduced nicotinamide riboside and with hydroperoxyl radical, yielding reduced nicotinamide riboside and hydroperoxide. The hyperhomocysteinemia of aging and dementia is attributed to decreased synthesis of adenosyl methionine by thioretinaco ozonide and ATP, causing decreased allosteric activation of cystathionine synthase and decreased allosteric inhibition of methylenetetrahydrofolate reductase and resulting in dysregulation of methionine metabolism. © 2015 by the Association of Clinical Scientists, Inc.

  5. Mechanism of neem limonoids-induced cell death in cancer: Role of oxidative phosphorylation.

    Science.gov (United States)

    Yadav, Neelu; Kumar, Sandeep; Kumar, Rahul; Srivastava, Pragya; Sun, Leimin; Rapali, Peter; Marlowe, Timothy; Schneider, Andrea; Inigo, Joseph R; O'Malley, Jordan; Londonkar, Ramesh; Gogada, Raghu; Chaudhary, Ajay K; Yadava, Nagendra; Chandra, Dhyan

    2016-01-01

    We have previously reported that neem limonoids (neem) induce multiple cancer cell death pathways. Here we dissect the underlying mechanisms of neem-induced apoptotic cell death in cancer. We observed that neem-induced caspase activation does not require Bax/Bak channel-mediated mitochondrial outer membrane permeabilization, permeability transition pore, and mitochondrial fragmentation. Neem enhanced mitochondrial DNA and mitochondrial biomass. While oxidative phosphorylation (OXPHOS) Complex-I activity was decreased, the activities of other OXPHOS complexes including Complex-II and -IV were unaltered. Increased reactive oxygen species (ROS) levels were associated with an increase in mitochondrial biomass and apoptosis upon neem exposure. Complex-I deficiency due to the loss of Ndufa1-encoded MWFE protein inhibited neem-induced caspase activation and apoptosis, but cell death induction was enhanced. Complex II-deficiency due to the loss of succinate dehydrogenase complex subunit C (SDHC) robustly decreased caspase activation, apoptosis, and cell death. Additionally, the ablation of Complexes-I, -III, -IV, and -V together did not inhibit caspase activation. Together, we demonstrate that neem limonoids target OXPHOS system to induce cancer cell death, which does not require upregulation or activation of proapoptotic Bcl-2 family proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Metabolic reprogramming during neuronal differentiation from aerobic glycolysis to neuronal oxidative phosphorylation.

    Science.gov (United States)

    Zheng, Xinde; Boyer, Leah; Jin, Mingji; Mertens, Jerome; Kim, Yongsung; Ma, Li; Ma, Li; Hamm, Michael; Gage, Fred H; Hunter, Tony

    2016-06-10

    How metabolism is reprogrammed during neuronal differentiation is unknown. We found that the loss of hexokinase (HK2) and lactate dehydrogenase (LDHA) expression, together with a switch in pyruvate kinase gene splicing from PKM2 to PKM1, marks the transition from aerobic glycolysis in neural progenitor cells (NPC) to neuronal oxidative phosphorylation. The protein levels of c-MYC and N-MYC, transcriptional activators of the HK2 and LDHA genes, decrease dramatically. Constitutive expression of HK2 and LDHA during differentiation leads to neuronal cell death, indicating that the shut-off aerobic glycolysis is essential for neuronal survival. The metabolic regulators PGC-1α and ERRγ increase significantly upon neuronal differentiation to sustain the transcription of metabolic and mitochondrial genes, whose levels are unchanged compared to NPCs, revealing distinct transcriptional regulation of metabolic genes in the proliferation and post-mitotic differentiation states. Mitochondrial mass increases proportionally with neuronal mass growth, indicating an unknown mechanism linking mitochondrial biogenesis to cell size.

  7. Salinity-dependent nickel accumulation and effects on respiration, ion regulation and oxidative stress in the galaxiid fish, Galaxias maculatus.

    Science.gov (United States)

    Blewett, Tamzin A; Wood, Chris M; Glover, Chris N

    2016-07-01

    Inanga (Galaxias maculatus) are a euryhaline and amphidromous Southern hemisphere fish species inhabiting waters highly contaminated in trace elements such as nickel (Ni). Ni is known to exert its toxic effects on aquatic biota via three key mechanisms: inhibition of respiration, impaired ion regulation, and stimulation of oxidative stress. Inanga acclimated to freshwater (FW), 50% seawater (SW) or 100% SW were exposed to 0, 150 or 2000 μg Ni L(-1), and tissue Ni accumulation, metabolic rate, ion regulation (tissue ions, calcium (Ca) ion influx), and oxidative stress (catalase activity, protein carbonylation) were measured after 96 h. Ni accumulation increased with Ni exposure concentration in gill, gut and remaining body, but not in liver. Only in the gill was Ni accumulation affected by exposure salinity, with lower branchial Ni burdens in 100% and 50% SW inanga, relative to FW fish. There were no Ni-dependent effects on respiration, or Ca influx, and the only Ni-dependent effect on tissue ion content was on gill potassium. Catalase activity and protein carbonylation were affected by Ni, primarily in FW, but only at 150 μg Ni L(-1). Salinity therefore offsets the effects of Ni, despite minimal changes in Ni bioavailability. These data suggest only minor effects of Ni in inanga, even at highly elevated environmental Ni concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Overexpression of mitochondrial oxodicarboxylate carrier (ODC1 preserves oxidative phosphorylation in a yeast model of Barth syndrome

    Directory of Open Access Journals (Sweden)

    Maxence de Taffin de Tilques

    2017-04-01

    Full Text Available Cardiolipin (CL is a diglycerol phospholipid mostly found in mitochondria where it optimizes numerous processes, including oxidative phosphorylation (OXPHOS. To function properly, CL needs to be unsaturated, which requires the acyltransferase tafazzin. Loss-of-function mutations in this protein are responsible for Barth syndrome (BTHS, presumably because of a diminished OXPHOS capacity. Here, we show that overexpressing Odc1p, a conserved oxodicarboxylic acid carrier located in the mitochondrial inner membrane, fully restores oxidative phosphorylation in a yeast model (taz1Δ of BTHS. The rescuing activity involves the recovery of normal expression of key components that sustain oxidative phosphorylation, including cytochrome c and electron transport chain complexes IV and III, which are strongly downregulated in taz1Δ yeast. Interestingly, overexpression of Odc1p was also shown previously to rescue yeast models of mitochondrial diseases caused by defects in the assembly of ATP synthase and by mutations in the MPV17 protein that result in hepatocerebral mitochondrial DNA depletion syndrome. These findings define the transport of oxodicarboxylic acids across the inner membrane as a potential therapeutic target for a large spectrum of mitochondrial diseases, including BTHS.

  9. Gene expression patterns of oxidative phosphorylation complex I subunits are organized in clusters.

    Directory of Open Access Journals (Sweden)

    Yael Garbian

    Full Text Available After the radiation of eukaryotes, the NUO operon, controlling the transcription of the NADH dehydrogenase complex of the oxidative phosphorylation system (OXPHOS complex I, was broken down and genes encoding this protein complex were dispersed across the nuclear genome. Seven genes, however, were retained in the genome of the mitochondrion, the ancient symbiote of eukaryotes. This division, in combination with the three-fold increase in subunit number from bacteria (N = approximately 14 to man (N = 45, renders the transcription regulation of OXPHOS complex I a challenge. Recently bioinformatics analysis of the promoter regions of all OXPHOS genes in mammals supported patterns of co-regulation, suggesting that natural selection favored a mechanism facilitating the transcriptional regulatory control of genes encoding subunits of these large protein complexes. Here, using real time PCR of mitochondrial (mtDNA- and nuclear DNA (nDNA-encoded transcripts in a panel of 13 different human tissues, we show that the expression pattern of OXPHOS complex I genes is regulated in several clusters. Firstly, all mtDNA-encoded complex I subunits (N = 7 share a similar expression pattern, distinct from all tested nDNA-encoded subunits (N = 10. Secondly, two sub-clusters of nDNA-encoded transcripts with significantly different expression patterns were observed. Thirdly, the expression patterns of two nDNA-encoded genes, NDUFA4 and NDUFA5, notably diverged from the rest of the nDNA-encoded subunits, suggesting a certain degree of tissue specificity. Finally, the expression pattern of the mtDNA-encoded ND4L gene diverged from the rest of the tested mtDNA-encoded transcripts that are regulated by the same promoter, consistent with post-transcriptional regulation. These findings suggest, for the first time, that the regulation of complex I subunits expression in humans is complex rather than reflecting global co-regulation.

  10. Oxidative phosphorylation-dependent regulation of cancer cell apoptosis in response to anticancer agents.

    Science.gov (United States)

    Yadav, N; Kumar, S; Marlowe, T; Chaudhary, A K; Kumar, R; Wang, J; O'Malley, J; Boland, P M; Jayanthi, S; Kumar, T K S; Yadava, N; Chandra, D

    2015-11-05

    Cancer cells tend to develop resistance to various types of anticancer agents, whether they adopt similar or distinct mechanisms to evade cell death in response to a broad spectrum of cancer therapeutics is not fully defined. Current study concludes that DNA-damaging agents (etoposide and doxorubicin), ER stressor (thapsigargin), and histone deacetylase inhibitor (apicidin) target oxidative phosphorylation (OXPHOS) for apoptosis induction, whereas other anticancer agents including staurosporine, taxol, and sorafenib induce apoptosis in an OXPHOS-independent manner. DNA-damaging agents promoted mitochondrial biogenesis accompanied by increased accumulation of cellular and mitochondrial ROS, mitochondrial protein-folding machinery, and mitochondrial unfolded protein response. Induction of mitochondrial biogenesis occurred in a caspase activation-independent mechanism but was reduced by autophagy inhibition and p53-deficiency. Abrogation of complex-I blocked DNA-damage-induced caspase activation and apoptosis, whereas inhibition of complex-II or a combined deficiency of OXPHOS complexes I, III, IV, and V due to impaired mitochondrial protein synthesis did not modulate caspase activity. Mechanistic analysis revealed that inhibition of caspase activation in response to anticancer agents associates with decreased release of mitochondrial cytochrome c in complex-I-deficient cells compared with wild type (WT) cells. Gross OXPHOS deficiencies promoted increased release of apoptosis-inducing factor from mitochondria compared with WT or complex-I-deficient cells, suggesting that cells harboring defective OXPHOS trigger caspase-dependent as well as caspase-independent apoptosis in response to anticancer agents. Interestingly, DNA-damaging agent doxorubicin showed strong binding to mitochondria, which was disrupted by complex-I-deficiency but not by complex-II-deficiency. Thapsigargin-induced caspase activation was reduced upon abrogation of complex-I or gross OXPHOS deficiency

  11. Xenobiotics that affect oxidative phosphorylation alter differentiation of human adipose-derived stem cells at concentrations that are found in human blood

    Directory of Open Access Journals (Sweden)

    Laura Llobet

    2015-11-01

    Full Text Available Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture or other human activities affect oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, such as ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. By contrast, the environmental chemical pollutant tributyltin chloride, which inhibits the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as postulated by the obesogen hypothesis.

  12. Linear programming model can explain respiration of fermentation products

    Science.gov (United States)

    Möller, Philip; Liu, Xiaochen; Schuster, Stefan

    2018-01-01

    Many differentiated cells rely primarily on mitochondrial oxidative phosphorylation for generating energy in the form of ATP needed for cellular metabolism. In contrast most tumor cells instead rely on aerobic glycolysis leading to lactate to about the same extent as on respiration. Warburg found that cancer cells to support oxidative phosphorylation, tend to ferment glucose or other energy source into lactate even in the presence of sufficient oxygen, which is an inefficient way to generate ATP. This effect also occurs in striated muscle cells, activated lymphocytes and microglia, endothelial cells and several mammalian cell types, a phenomenon termed the “Warburg effect”. The effect is paradoxical at first glance because the ATP production rate of aerobic glycolysis is much slower than that of respiration and the energy demands are better to be met by pure oxidative phosphorylation. We tackle this question by building a minimal model including three combined reactions. The new aspect in extension to earlier models is that we take into account the possible uptake and oxidation of the fermentation products. We examine the case where the cell can allocate protein on several enzymes in a varying distribution and model this by a linear programming problem in which the objective is to maximize the ATP production rate under different combinations of constraints on enzymes. Depending on the cost of reactions and limitation of the substrates, this leads to pure respiration, pure fermentation, and a mixture of respiration and fermentation. The model predicts that fermentation products are only oxidized when glucose is scarce or its uptake is severely limited. PMID:29415045

  13. Linear programming model can explain respiration of fermentation products.

    Science.gov (United States)

    Möller, Philip; Liu, Xiaochen; Schuster, Stefan; Boley, Daniel

    2018-01-01

    Many differentiated cells rely primarily on mitochondrial oxidative phosphorylation for generating energy in the form of ATP needed for cellular metabolism. In contrast most tumor cells instead rely on aerobic glycolysis leading to lactate to about the same extent as on respiration. Warburg found that cancer cells to support oxidative phosphorylation, tend to ferment glucose or other energy source into lactate even in the presence of sufficient oxygen, which is an inefficient way to generate ATP. This effect also occurs in striated muscle cells, activated lymphocytes and microglia, endothelial cells and several mammalian cell types, a phenomenon termed the "Warburg effect". The effect is paradoxical at first glance because the ATP production rate of aerobic glycolysis is much slower than that of respiration and the energy demands are better to be met by pure oxidative phosphorylation. We tackle this question by building a minimal model including three combined reactions. The new aspect in extension to earlier models is that we take into account the possible uptake and oxidation of the fermentation products. We examine the case where the cell can allocate protein on several enzymes in a varying distribution and model this by a linear programming problem in which the objective is to maximize the ATP production rate under different combinations of constraints on enzymes. Depending on the cost of reactions and limitation of the substrates, this leads to pure respiration, pure fermentation, and a mixture of respiration and fermentation. The model predicts that fermentation products are only oxidized when glucose is scarce or its uptake is severely limited.

  14. Seeking homeostasis: Temporal trends in respiration, oxidation, and calcium in SOD1 G93A Amyotrophic Lateral Sclerosis mice

    Directory of Open Access Journals (Sweden)

    Cameron W Irvin

    2015-07-01

    Full Text Available Impairments in mitochondria, oxidative regulation, and calcium homeostasis have been well documented in numerous amyotrophic lateral sclerosis (ALS experimental models, especially in the superoxide dismutase 1 glycine 93 to alanine (SOD1 G93A transgenic mouse. However, the timing of these deficiencies has been debatable. In a systematic review of 45 articles, we examine experimental measurements of cellular respiration, mitochondrial mechanisms, oxidative markers, and calcium regulation. We evaluate the quantitative magnitude and statistical temporal trend of these aggregated assessments in high transgene copy SOD1 G93A mice compared to wild type mice. Analysis of overall trends reveals cellular respiration, intracellular ATP, and corresponding mitochondrial elements (Cox, cytochrome c, complex I, enzyme activity are depressed for the entire lifespan of the SOD1 G93A mouse. Oxidant markers (H2O2, 8OH2’dG, MDA are initially similar to wild type but are double that of wild type by the time of symptom onset despite early post-natal elevation of protective heat shock proteins. All aspects of calcium regulation show early disturbances, although a notable and likely compensatory convergence to near wild type levels appears to occur between 40-80 days (pre-onset, followed by a post-onset elevation in intracellular calcium. The identified temporal trends and compensatory fluctuations provide evidence that the cause of ALS may lay within failed homeostatic regulation, itself, rather than any one particular perturbing event or cellular mechanism. We discuss the vulnerabilities of motoneurons to regulatory instability and possible hypotheses regarding failed regulation and its potential treatment in ALS.

  15. Inhibition of oxidative phosphorylation for enhancing citric acid production by Aspergillus niger.

    Science.gov (United States)

    Wang, Lu; Zhang, Jianhua; Cao, Zhanglei; Wang, Yajun; Gao, Qiang; Zhang, Jian; Wang, Depei

    2015-01-16

    The spore germination rate and growth characteristics were compared between the citric acid high-yield strain Aspergillus niger CGMCC 5751 and A. niger ATCC 1015 in media containing antimycin A or DNP. We inferred that differences in citric acid yield might be due to differences in energy metabolism between these strains. To explore the impact of energy metabolism on citric acid production, the changes in intracellular ATP, NADH and NADH/NAD+ were measured at various fermentation stages. In addition, the effects of antimycin A or DNP on energy metabolism and citric acid production was investigated by CGMCC 5751. By comparing the spore germination rate and the extent of growth on PDA plates containing antimycin A or DNP, CGMCC 5751 was shown to be more sensitive to antimycin A than ATCC 1015. The substrate-level phosphorylation of CGMCC 5751 was greater than that of ATCC 1015 on PDA plates with DNP. DNP at tested concentrations had no apparent effect on the growth of CGMCC 5751. There were no apparent effects on the mycelial morphology, the growth of mycelial pellets or the dry cell mass when 0.2 mg L(-1) antimycin A or 0.1 mg L(-1) DNP was added to medium at the 24-h time point. The concentrations of intracellular ATP, NADH and NADH/NAD+ of CGMCC 5751 were notably lower than those of ATCC 1015 at several fermentation stages. Moreover, at 96 h of fermentation, the citric acid production of CGMCC 5751 reached up to 151.67 g L(-1) and 135.78 g L(-1) by adding 0.2 mg L(-1) antimycin A or 0.1 mg L(-1) DNP, respectively, at the 24-h time point of fermentation. Thus, the citric acid production of CGMCC 5751 was increased by 19.89% and 7.32%, respectively. The concentrations of intracellular ATP, NADH and NADH/NAD+ of the citric acid high-yield strain CGMCC 5751 were notably lower than those of ATCC 1015. The excessive ATP has a strong inhibitory effect on citric acid accumulation by A. niger. Increasing NADH oxidation and appropriately reducing the concentration of

  16. Expression of genes belonging to the interacting TLR cascades, NADPH-oxidase and mitochondrial oxidative phosphorylation in septic patients.

    Directory of Open Access Journals (Sweden)

    Laura A Nucci

    Full Text Available Sepsis is a complex disease that is characterized by activation and inhibition of different cell signaling pathways according to the disease stage. Here, we evaluated genes involved in the TLR signaling pathway, oxidative phosphorylation and oxidative metabolism, aiming to assess their interactions and resulting cell functions and pathways that are disturbed in septic patients.Blood samples were obtained from 16 patients with sepsis secondary to community acquired pneumonia at admission (D0, and after 7 days (D7, N = 10 of therapy. Samples were also collected from 8 healthy volunteers who were matched according to age and gender. Gene expression of 84 genes was performed by real-time polymerase chain reactions. Their expression was considered up- or down-regulated when the fold change was greater than 1.5 compared to the healthy volunteers. A p-value of ≤ 0.05 was considered significant.Twenty-two genes were differently expressed in D0 samples; most of them were down-regulated. When gene expression was analyzed according to the outcomes, higher number of altered genes and a higher intensity in the disturbance was observed in non-survivor than in survivor patients. The canonical pathways altered in D0 samples included interferon and iNOS signaling; the role of JAK1, JAK2 and TYK2 in interferon signaling; mitochondrial dysfunction; and superoxide radical degradation pathways. When analyzed according to outcomes, different pathways were disturbed in surviving and non-surviving patients. Mitochondrial dysfunction, oxidative phosphorylation and superoxide radical degradation pathway were among the most altered in non-surviving patients.Our data show changes in the expression of genes belonging to the interacting TLR cascades, NADPH-oxidase and oxidative phosphorylation. Importantly, distinct patterns are clearly observed in surviving and non-surviving patients. Interferon signaling, marked by changes in JAK-STAT modulation, had prominent changes in

  17. Mitochondrial NAD(PH in vivo: identifying natural indicators of oxidative phosphorylation in the 31P magnetic resonance spectrum.

    Directory of Open Access Journals (Sweden)

    Kevin eConley

    2016-03-01

    Full Text Available Natural indicators provide intrinsic probes of metabolism, biogenesis and oxidative protection. Nicotinamide adenine dinucleotide metabolites (NAD(P are one class of indicators that have roles as co-factors in oxidative phosphorylation, glycolysis and anti-oxidant protection, as well as signaling in the mitochondrial biogenesis pathway. These many roles are made possible by the distinct redox states (NAD(P+ and NAD(PH, which are compartmentalized between cell and mitochondria. Here we provide evidence for detection of NAD(P+ and NAD(PH in separate mitochondrial and cell pools in vivo in human tissue by phosphorus magnetic resonance spectroscopy (31P MRS. These NAD(P pools are identified by chemical standards (NAD+, NADP+ and NADH and by physiological tests. A unique resonance reflecting mitochondrial NAD(PH is revealed by the changes elicited by elevation of mitochondrial oxidation. The decline of NAD(PH with oxidation is matched by a stoichiometric rise in the NAD(P+ peak. This unique resonance also provides a measure of the improvement in mitochondrial oxidation that parallels the greater phosphorylation found after exercise training in these elderly subjects. The implication is that the dynamics of the mitochondrial NAD(PH peak provides an intrinsic probe of the reversal of mitochondrial dysfunction in elderly muscle. Thus non-invasive detection of NAD(P+ and NAD(PH in cell vs. mitochondria yield natural indicators of redox compartmentalization and sensitive intrinsic probes of the improvement of mitochondrial function with an intervention in human tissues in vivo. These natural indicators hold the promise of providing mechanistic insight into metabolism and mitochondrial function in vivo in a range of tissues in health, disease and with treatment.

  18. Abnormal mitochondrial respiration in failed human myocardium.

    Science.gov (United States)

    Sharov, V G; Todor, A V; Silverman, N; Goldstein, S; Sabbah, H N

    2000-12-01

    Chronic heart failure (HF) is associated with morphologic abnormalities of cardiac mitochondria including hyperplasia, reduced organelle size and compromised structural integrity. In this study, we examined whether functional abnormalities of mitochondrial respiration are also present in myocardium of patients with advanced HF. Mitochondrial respiration was examined using a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles obtained from myocardium of failed explanted human hearts due to ischemic (ICM, n=9) or idiopathic dilated (IDC, n=9) cardiomyopathy. Myocardial specimens from five normal donor hearts served as controls (CON). Basal respiratory rate, respiratory rate after addition of the substrates glutamate and malate (V(SUB)), state 3 respiration (after addition of ADP, V(ADP)) and respiration after the addition of atractyloside (V(AT)) were measured in scar-free muscle bundles obtained from the subendocardial (ENDO) and subepicardial (EPI) thirds of the left ventricular (LV) free wall, interventricular septum and right ventricular (RV) free wall. There were no differences in basal and substrate-supported respiration between CON and HF regardless of etiology. V(ADP)was significantly depressed both in ICM and IDC compared to CON in all the regions studied. The respiratory control ratio, V(ADP)/V(AT), was also significantly decreased in HF compared to CON. In both ICM and IDC, V(ADP)was significantly lower in ENDO compared to EPI. The results indicate that mitochondrial respiration is abnormal in the failing human heart. The findings support the concept of low myocardial energy production in HF via oxidative phosphorylation, an abnormality with a potentially impact on global cardiac performance. Copyright 2000 Academic Press.

  19. Anaerobic Respiration Using a Complete Oxidative TCA Cycle Drives Multicellular Swarming in Proteus mirabilis

    Science.gov (United States)

    Alteri, Christopher J.; Himpsl, Stephanie D.; Engstrom, Michael D.; Mobley, Harry L. T.

    2012-01-01

    ABSTRACT Proteus mirabilis rapidly migrates across surfaces using a periodic developmental process of differentiation alternating between short swimmer cells and elongated hyperflagellated swarmer cells. To undergo this vigorous flagellum-mediated motility, bacteria must generate a substantial proton gradient across their cytoplasmic membranes by using available energy pathways. We sought to identify the link between energy pathways and swarming differentiation by examining the behavior of defined central metabolism mutants. Mutations in the tricarboxylic acid (TCA) cycle (fumC and sdhB mutants) caused altered patterns of swarming periodicity, suggesting an aerobic pathway. Surprisingly, the wild-type strain swarmed on agar containing sodium azide, which poisons aerobic respiration; the fumC TCA cycle mutant, however, was unable to swarm on azide. To identify other contributing energy pathways, we screened transposon mutants for loss of swarming on sodium azide and found insertions in the following genes that involved fumarate metabolism or respiration: hybB, encoding hydrogenase; fumC, encoding fumarase; argH, encoding argininosuccinate lyase (generates fumarate); and a quinone hydroxylase gene. These findings validated the screen and suggested involvement of anaerobic electron transport chain components. Abnormal swarming periodicity of fumC and sdhB mutants was associated with the excretion of reduced acidic fermentation end products. Bacteria lacking SdhB were rescued to wild-type pH and periodicity by providing fumarate, independent of carbon source but dependent on oxygen, while fumC mutants were rescued by glycerol, independent of fumarate only under anaerobic conditions. These findings link multicellular swarming patterns with fumarate metabolism and membrane electron transport using a previously unappreciated configuration of both aerobic and anaerobic respiratory chain components. PMID:23111869

  20. Rat Aquaporin-5 Is pH-Gated Induced by Phosphorylation and Is Implicated in Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Claudia Rodrigues

    2016-12-01

    Full Text Available Aquaporin-5 (AQP5 is a membrane water channel widely distributed in human tissues that was found up-regulated in different tumors and considered implicated in carcinogenesis in different organs and systems. Despite its wide distribution pattern and physiological importance, AQP5 short-term regulation was not reported and mechanisms underlying its involvement in cancer are not well defined. In this work, we expressed rat AQP5 in yeast and investigated mechanisms of gating, as well as AQP5’s ability to facilitate H2O2 plasma membrane diffusion. We found that AQP5 can be gated by extracellular pH in a phosphorylation-dependent manner, with higher activity at physiological pH 7.4. Moreover, similar to other mammalian AQPs, AQP5 is able to increase extracellular H2O2 influx and to affect oxidative cell response with dual effects: whereas in acute oxidative stress conditions AQP5 induces an initial higher sensitivity, in chronic stress AQP5 expressing cells show improved cell survival and resistance. Our findings support the involvement of AQP5 in oxidative stress and suggest AQP5 modulation by phosphorylation as a novel tool for therapeutics.

  1. Dysfunctional oxidative phosphorylation makes malignant melanoma cells addicted to glycolysis driven by the (V600E)BRAF oncogene

    DEFF Research Database (Denmark)

    Hall, Arnaldur; Meyle, Kathrine Damm; Lange, Marina Krarup

    2013-01-01

    basis for this addiction is largely unknown. Here we provide evidence for a metabolic rationale behind the addiction to (V600E)BRAF in two malignant melanoma cell lines. Both cell lines display a striking addiction to glycolysis due to underlying dysfunction of oxidative phosphorylation (OXPHOS......). Notably, even minor reductions in glycolytic activity lead to increased OXPHOS activity (reversed Warburg effect), however the mitochondria are unable to sustain ATP production. We show that (V600E)BRAF upholds the activity of glycolysis and therefore the addiction to glycolysis de facto becomes...

  2. Dysfunctional oxidative phosphorylation makes malignant melanoma cells addicted to glycolysis driven by the V600EBRAF oncogene

    DEFF Research Database (Denmark)

    Hall, Arnaldur; Meyle, Kathrine Damm; Lange, Marina Krarup

    2013-01-01

    basis for this addiction is largely unknown. Here we provide evidence for a metabolic rationale behind the addiction to V600EBRAF in two malignant melanoma cell lines. Both cell lines display a striking addiction to glycolysis due to underlying dysfunction of oxidative phosphorylation (OXPHOS). Notably......, even minor reductions in glycolytic activity lead to increased OXPHOS activity (reversed Warburg effect), however the mitochondria are unable to sustain ATP production. We show that V600EBRAF upholds the activity of glycolysis and therefore the addiction to glycolysis de facto becomes an addiction to V...

  3. Convergent signaling pathways – interaction between methionine oxidation and serine/threonine/tyrosine O-phosphorylation

    Science.gov (United States)

    Oxidation of Methionine (Met) to Met sulfoxide (MetSO) is a frequently found reversible post-translational modification. It has been presumed that the major functional role for oxidation-labile Met residues is to protect proteins/cells from oxidative stress. However, Met oxidation has been establi...

  4. Changes in mitochondrial respiration in the human placenta over gestation.

    Science.gov (United States)

    Holland, Olivia J; Hickey, Anthony J R; Alvsaker, Anna; Moran, Stephanie; Hedges, Christopher; Chamley, Lawrence W; Perkins, Anthony V

    2017-09-01

    Placental mitochondria are subjected to micro-environmental changes throughout gestation, in particular large variations in oxygen. How placental mitochondrial respiration adapts to changing oxygen concentrations remains unexplored. Additionally, placental tissue is often studied in culture; however, the effect of culture on placental mitochondria is unclear. Placental tissue was obtained from first trimester and term (laboured and non-laboured) pregnancies, and selectively permeabilized to access mitochondria. Respirometry was used to compare respiration states and substrate use in mitochondria. Additionally, explants of placental tissue were cultured for four, 12, 24, 48, or 96 h and respiration measured. Mitochondrial respiration decreased at 11 weeks compared to earlier gestations (p = 0.05-0.001), and mitochondrial content increased at 12-13 weeks compared to 7-10 weeks (p = 0.042). In term placentae, oxidative phosphorylation (OXPHOS) through mitochondrial complex IV (p Respiration was increased (p ≤ 0.006-0.001) in laboured compared to non-laboured placenta. After four hours of culture, respiration was depressed compared to fresh tissue from the same placenta and continued to decline with time in culture. Markers of apoptosis were increased, while markers of autophagy, mitochondrial biogenesis, and mitochondrial membrane potential were decreased after four hours of culture. Respiration and mitochondrial content alter over gestation/with labour. Decreased respiration at 11 weeks and increased mitochondrial content at 12-13 weeks may relate to onset of maternal blood flow, and increased respiration as a result of labour may be an adaptation to ischaemia-reperfusion. At term, mitochondria were more susceptible to changes in respiratory function relative to first trimester when cultured in vitro, perhaps reflecting changes in metabolic demands as gestation progresses. Metabolic plasticity of placental mitochondria has relevance to placenta

  5. The HK2 Dependent "Warburg Effect" and Mitochondrial Oxidative Phosphorylation in Cancer: Targets for Effective Therapy with 3-Bromopyruvate.

    Science.gov (United States)

    Lis, Paweł; Dyląg, Mariusz; Niedźwiecka, Katarzyna; Ko, Young H; Pedersen, Peter L; Goffeau, Andre; Ułaszewski, Stanisław

    2016-12-15

    This review summarizes the current state of knowledge about the metabolism of cancer cells, especially with respect to the "Warburg" and "Crabtree" effects. This work also summarizes two key discoveries, one of which relates to hexokinase-2 (HK2), a major player in both the "Warburg effect" and cancer cell immortalization. The second discovery relates to the finding that cancer cells, unlike normal cells, derive as much as 60% of their ATP from glycolysis via the "Warburg effect", and the remaining 40% is derived from mitochondrial oxidative phosphorylation. Also described are selected anticancer agents which generally act as strong energy blockers inside cancer cells. Among them, much attention has focused on 3-bromopyruvate (3BP). This small alkylating compound targets both the "Warburg effect", i.e., elevated glycolysis even in the presence oxygen, as well as mitochondrial oxidative phosphorylation in cancer cells. Normal cells remain unharmed. 3BP rapidly kills cancer cells growing in tissue culture, eradicates tumors in animals, and prevents metastasis. In addition, properly formulated 3BP shows promise also as an effective anti-liver cancer agent in humans and is effective also toward cancers known as "multiple myeloma". Finally, 3BP has been shown to significantly extend the life of a human patient for which no other options were available. Thus, it can be stated that 3BP is a very promising new anti-cancer agent in the process of undergoing clinical development.

  6. Glyoxalase I reduces glycative and oxidative stress and prevents age-related endothelial dysfunction through modulation of endothelial nitric oxide synthase phosphorylation.

    Science.gov (United States)

    Jo-Watanabe, Airi; Ohse, Takamoto; Nishimatsu, Hiroaki; Takahashi, Masao; Ikeda, Yoichiro; Wada, Takehiko; Shirakawa, Jun-ichi; Nagai, Ryoji; Miyata, Toshio; Nagano, Tetsuo; Hirata, Yasunobu; Inagi, Reiko; Nangaku, Masaomi

    2014-06-01

    Endothelial dysfunction is a major contributor to cardiovascular disease (CVD), particularly in elderly people. Studies have demonstrated the role of glycation in endothelial dysfunction in nonphysiological models, but the physiological role of glycation in age-related endothelial dysfunction has been poorly addressed. Here, to investigate how vascular glycation affects age-related endothelial function, we employed rats systemically overexpressing glyoxalase I (GLO1), which detoxifies methylglyoxal (MG), a representative precursor of glycation. Four groups of rats were examined, namely young (13 weeks old), mid-age (53 weeks old) wild-type, and GLO1 transgenic (WT/GLO1 Tg) rats. Age-related acceleration in glycation was attenuated in GLO1 Tg rats, together with lower aortic carboxymethyllysine (CML) and urinary 8-hydroxydeoxyguanosine (8-OHdG) levels. Age-related impairment of endothelium-dependent vasorelaxation was attenuated in GLO1 Tg rats, whereas endothelium-independent vasorelaxation was not different between WT and GLO1 Tg rats. Nitric oxide (NO) production was decreased in mid-age WT rats, but not in mid-age GLO1 Tg rats. Age-related inactivation of endothelial NO synthase (eNOS) due to phosphorylation of eNOS on Thr495 and dephosphorylation on Ser1177 was ameliorated in GLO1 Tg rats. In vitro, MG increased phosphorylation of eNOS (Thr495) in primary human aortic endothelial cells (HAECs), and overexpression of GLO1 decreased glycative stress and phosphorylation of eNOS (Thr495). Together, GLO1 reduced age-related endothelial glycative and oxidative stress, altered phohphorylation of eNOS, and attenuated endothelial dysfunction. As a molecular mechanism, GLO1 lessened inhibitory phosphorylation of eNOS (Thr495) by reducing glycative stress. Our study demonstrates that blunting glycative stress prevents the long-term impact of endothelial dysfunction on vascular aging. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons

  7. Oxygen supply and oxidative phosphorylation limitation in rat myocardium in situ.

    Science.gov (United States)

    Kreutzer, U; Mekhamer, Y; Chung, Y; Jue, T

    2001-05-01

    The 1H-NMR signal of the proximal histidyl-N(delta)H of deoxymyoglobin is detectable in the in situ rat myocardium and can reflect the intracellular PO2. Under basal normoxic conditions, the cellular PO2 is sufficient to saturate myoglobin (Mb). No proximal histidyl signal of Mb is detectable. On ligation of the left anterior descending coronary artery, the Mb signal at 78 parts/million (ppm) appears, along with a peak shoulder assigned to the corresponding signal of Hb. During dopamine infusion up to 80 microg. kg(-1) x min(-1), both the heart rate-pressure product (RPP) and myocardial oxygen consumption (MVO2) increase by about a factor of 2. Coronary flow increases by 84%, and O2 extraction (arteriovenous O2 difference) rises by 31%. Despite the increased respiration and work, no deoxymyoglobin signal is detected, implying that the intracellular O2 level still saturates MbO2, well above the PO2 at 50% saturation of Mb. The phosphocreatine (PCr) level decreases, however, during dopamine stimulation, and the ratio of the change in P(i) over PCr (DeltaP(i)/PCr) increases by 0.19. Infusion of either pyruvate, as the primary substrate, or dichloroacetate, a pyruvate dehydrogenase activator, abolishes the change in DeltaP(i)/PCr. Intracellular O2 supply does not limit MVO2, and the role of ADP in regulating respiration in rat myocardium in vivo remains an open question.

  8. Two weeks of metformin treatment enhances mitochondrial respiration in skeletal muscle of AMPK kinase dead but not wild type mice

    DEFF Research Database (Denmark)

    Kristensen, Jonas Møller; Larsen, Steen; Helge, Jørn Wulff

    2013-01-01

    signaling. We investigated this by two weeks of oral metformin treatment of muscle specific kinase dead a(2) (KD) AMPK mice and wild type (WT) littermates. We measured mitochondrial respiration and protein activity and expressions of key enzymes involved in mitochondrial carbohydrate and fat metabolism...... and oxidative phosphorylation. Mitochondrial respiration, HAD and CS activity, PDH and complex I-V and cytochrome c protein expression were all reduced in AMPK KD compared to WT tibialis anterior muscles. Surprisingly, metformin treatment only enhanced respiration in AMPK KD mice and thereby rescued...... the respiration defect compared to the WT mice. Metformin did not influence protein activities or expressions in either WT or AMPK KD mice.We conclude that two weeks of in vivo metformin treatment enhances mitochondrial respiration in the mitochondrial deficient AMPK KD but not WT mice. The improvement seems...

  9. Impact of hypoxia stress on the physiological responses of sea cucumber Apostichopus japonicus: respiration, digestion, immunity and oxidative damage

    Directory of Open Access Journals (Sweden)

    Da Huo

    2018-04-01

    Full Text Available Hypoxia is one of the most frequently occurring stressors confronted by industrial cultures of sea cucumber and can cause large economic losses and resource degradation. However, its responsive mechanisms are still lacking. In this paper, the physiological responses of Apostichopus japonicus to oxygen deficiency was illustrated, including induced oxidative response and immune defense and changed digestive enzymes activities. Significantly increased activities of alpha-amylase (AMS, acid phosphatase (ACP, lactate dehydrogenase, catalase, peroxidase, succinate dehydrogenase and higher content of malondialdehyde, and decreased activities of lipase and trypsin (TRY were observed after hypoxia exposure (dissolved oxygen [DO] 2 mg/L. Expressions of key genes showed that AMS, peptidase, ACP, alkaline phosphatase, lysozyme, heat shock protein 70 and glutathione peroxidase were increased and TRY was decreased under hypoxia. With the decline of the DO level, the decreased tendency of oxygen consumption rates was different in varied weight groups. Moreover, respiratory trees were observed degraded under long-term hypoxia stress, thus leading a negative effect of respiration. These results could help to develop a better understanding of the responsive mechanism of sea cucumber under hypoxia stress and provide a theoretical basis for the prevention of hypoxia risk.

  10. In yeast redistribution of Sod1 to the mitochondrial intermembrane space provides protection against respiration derived oxidative stress.

    Science.gov (United States)

    Klöppel, Christine; Michels, Christine; Zimmer, Julia; Herrmann, Johannes M; Riemer, Jan

    2010-12-03

    The antioxidative enzyme copper-zinc superoxide dismutase (Sod1) is an important cellular defence system against reactive oxygen species (ROS). While the majority of this enzyme is localized to the cytosol, about 1% of the cellular Sod1 is present in the intermembrane space (IMS) of mitochondria. These amounts of mitochondrial Sod1 are increased for certain Sod1 mutants that are linked to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). To date, only little is known about the physiological function of mitochondrial Sod1. Here, we use the model system Saccharomyces cerevisiae to generate cells in which Sod1 is exclusively localized to the IMS. We find that IMS-localized Sod1 can functionally substitute wild type Sod1 and that it even exceeds the protective capacity of wild type Sod1 under conditions of mitochondrial ROS stress. Moreover, we demonstrate that upon expression in yeast cells the common ALS-linked mutant Sod1(G93A) becomes enriched in the mitochondrial fraction and provides an increased protection of cells from mitochondrial oxidative stress. Such an effect cannot be observed for the catalytically inactive mutant Sod1(G85R). Our observations suggest that the targeting of Sod1 to the mitochondrial IMS provides an increased protection against respiration-derived ROS. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Genomic Analysis of Anaerobic Respiration in the Archaeon Halobacterium sp. Strain NRC-1: Dimethyl Sulfoxide and Trimethylamine N-Oxide as Terminal Electron Acceptors†

    OpenAIRE

    Müller, Jochen A.; DasSarma, Shiladitya

    2005-01-01

    We have investigated anaerobic respiration of the archaeal model organism Halobacterium sp. strain NRC-1 by using phenotypic and genetic analysis, bioinformatics, and transcriptome analysis. NRC-1 was found to grow on either dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO) as the sole terminal electron acceptor, with a doubling time of 1 day. An operon, dmsREABCD, encoding a putative regulatory protein, DmsR, a molybdopterin oxidoreductase of the DMSO reductase family (DmsEABC), and...

  12. 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.

  13. The Low Energy-Coupling Respiration in Zymomonas mobilis Accelerates Flux in the Entner-Doudoroff Pathway.

    Directory of Open Access Journals (Sweden)

    Reinis Rutkis

    Full Text Available Performing oxidative phosphorylation is the primary role of respiratory chain both in bacteria and eukaryotes. Yet, the branched respiratory chains of prokaryotes contain alternative, low energy-coupling electron pathways, which serve for functions other than oxidative ATP generation (like those of respiratory protection, adaptation to low-oxygen media, redox balancing, etc., some of which are still poorly understood. We here demonstrate that withdrawal of reducing equivalents by the energetically uncoupled respiratory chain of the bacterium Zymomonas mobilis accelerates its fermentative catabolism, increasing the glucose consumption rate. This is in contrast to what has been observed in other respiring bacteria and yeast. This effect takes place after air is introduced to glucose-consuming anaerobic cell suspension, and can be simulated using a kinetic model of the Entner-Doudoroff pathway in combination with a simple net reaction of NADH oxidation that does not involve oxidative phosphorylation. Although aeration hampers batch growth of respiring Z. mobilis culture due to accumulation of toxic byproducts, nevertheless under non-growing conditions respiration is shown to confer an adaptive advantage for the wild type over the non-respiring Ndh knock-out mutant. If cells get occasional access to limited amount of glucose for short periods of time, the elevated glucose uptake rate selectively improves survival of the respiring Z. mobilis phenotype.

  14. Glutaredoxin-2 is required to control oxidative phosphorylation in cardiac muscle by mediating deglutathionylation reactions.

    Science.gov (United States)

    Mailloux, Ryan J; Xuan, Jian Ying; McBride, Skye; Maharsy, Wael; Thorn, Stephanie; Holterman, Chet E; Kennedy, Christopher R J; Rippstein, Peter; deKemp, Robert; da Silva, Jean; Nemer, Mona; Lou, Marjorie; Harper, Mary-Ellen

    2014-05-23

    Glutaredoxin-2 (Grx2) modulates the activity of several mitochondrial proteins in cardiac tissue by catalyzing deglutathionylation reactions. However, it remains uncertain whether Grx2 is required to control mitochondrial ATP output in heart. Here, we report that Grx2 plays a vital role modulating mitochondrial energetics and heart physiology by mediating the deglutathionylation of mitochondrial proteins. Deletion of Grx2 (Grx2(-/-)) decreased ATP production by complex I-linked substrates to half that in wild type (WT) mitochondria. Decreased respiration was associated with increased complex I glutathionylation diminishing its activity. Tissue glucose uptake was concomitantly increased. Mitochondrial ATP output and complex I activity could be recovered by restoring the redox environment to that favoring the deglutathionylated states of proteins. Grx2(-/-) hearts also developed left ventricular hypertrophy and fibrosis, and mice became hypertensive. Mitochondrial energetics from Grx2 heterozygotes (Grx2(+/-)) were also dysfunctional, and hearts were hypertrophic. Intriguingly, Grx2(+/-) mice were far less hypertensive than Grx2(-/-) mice. Thus, Grx2 plays a vital role in modulating mitochondrial metabolism in cardiac muscle, and Grx2 deficiency leads to pathology. As mitochondrial ATP production was restored by the addition of reductants, these findings may be relevant to novel redox-related therapies in cardiac disease. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Identification of KCa3.1 channel as a novel regulator of Oxidative phosphorylation in a subset of pancreatic carcinoma cell lines

    DEFF Research Database (Denmark)

    Kovalenko, Ilya; Glasauer, Andrea; Schöckel, Laura

    2016-01-01

    , our goal was to identify novel transporters or channels that regulate oxidative phosphorylation (OxPhos) in PDAC in order to characterize novel potential drug targets for the treatment of these cancers. We set up a Seahorse Analyzer XF based siRNA screen and identified previously described as well...

  16. Endothelial Nitric Oxide Synthase Phosphorylation at Threonine 495 and Mitochondrial Reactive Oxygen Species Formation in Response to a High H2O2 Concentration

    DEFF Research Database (Denmark)

    Guterbaum, Thomas Jeremy; Braunstein, Thomas Hartig; Fossum, A

    2013-01-01

    Hydrogen peroxide (H₂O₂) is produced in vessels during ischemia/reperfusion and during inflammation, both leading to vascular dysfunction. We investigated cellular pathways involved in endothelial nitric oxide synthase (eNOS) phosphorylation at Threonine 495 (Thr(495)) in human umbilical vein end...

  17. Analysis of effects of 2,2',5,5'-tetracholorobiphenyl on the flux control in oxidative phosphorylation system in rat liver mitochondria.

    NARCIS (Netherlands)

    Mildaziene, V.; Nauciene, Z.; Baniene, R.; Demin, O.V.; Krab, K.

    2002-01-01

    Modular kinetic analysis reveals that the environmental pollutant 2,2′,5,5′tetrachlorobiphenyl (2,2′,5,5′-TCB) affects a large number of steps in oxidative phosphorylation in rat liver mitochondria. 2,2′,5,5′-TCB increases membrane permeability to ions, and inhibits NADH dehydrogenase, cytochrome

  18. Ob/ob mouse livers show decreased oxidative phosphorylation efficiencies and anaerobic capacities after cold ischemia.

    Directory of Open Access Journals (Sweden)

    Michael J J Chu

    Full Text Available BACKGROUND: Hepatic steatosis is a major risk factor for graft failure in liver transplantation. Hepatic steatosis shows a greater negative influence on graft function following prolonged cold ischaemia. As the impact of steatosis on hepatocyte metabolism during extended cold ischaemia is not well-described, we compared markers of metabolic capacity and mitochondrial function in steatotic and lean livers following clinically relevant durations of cold preservation. METHODS: Livers from 10-week old leptin-deficient obese (ob/ob, n = 9 and lean C57 mice (n = 9 were preserved in ice-cold University of Wisconsin solution. Liver mitochondrial function was then assessed using high resolution respirometry after 1.5, 3, 5, 8, 12, 16 and 24 hours of storage. Metabolic marker enzymes for anaerobiosis and mitochondrial mass were also measured in conjunction with non-bicarbonate tissue pH buffering capacity. RESULTS: Ob/ob and lean mice livers showed severe (>60% macrovesicular and mild (<30% microvesicular steatosis on Oil Red O staining, respectively. Ob/ob livers had lower baseline enzymatic complex I activity but similar adenosine triphosphate (ATP levels compared to lean livers. During cold storage, the respiratory control ratio and complex I-fueled phosphorylation deteriorated approximately twice as fast in ob/ob livers compared to lean livers. Ob/ob livers also demonstrated decreased ATP production capacities at all time-points analyzed compared to lean livers. Ob/ob liver baseline lactate dehydrogenase activities and intrinsic non-bicarbonate buffering capacities were depressed by 60% and 40%, respectively compared to lean livers. CONCLUSIONS: Steatotic livers have impaired baseline aerobic and anaerobic capacities compared to lean livers, and mitochondrial function indices decrease particularly from after 5 hours of cold preservation. These data provide a mechanistic basis for the clinical recommendation of shorter cold storage durations in

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  20. Increased platelet mitochondrial respiration after cardiac arrest and resuscitation as a potential peripheral biosignature of cerebral bioenergetic dysfunction.

    Science.gov (United States)

    Ferguson, Michael A; Sutton, Robert M; Karlsson, Michael; Sjövall, Fredrik; Becker, Lance B; Berg, Robert A; Margulies, Susan S; Kilbaugh, Todd J

    2016-06-01

    Cardiac arrest (CA) results in a sepsis-like syndrome with activation of the innate immune system and increased mitochondrial bioenergetics. To determine if platelet mitochondrial respiration increases following CA in a porcine pediatric model of asphyxia-associated ventricular fibrillation (VF) CA, and if this readily obtained biomarker is associated with decreased brain mitochondrial respiration. CA protocol: 7 min of asphyxia, followed by VF, protocolized titration of compression depth to systolic blood pressure of 90 mmHg and vasopressor administration to a coronary perfusion pressure greater than 20 mmHg. platelet integrated mitochondrial electron transport system (ETS) function evaluated pre- and post-CA/ROSC four hours after return of spontaneous circulation (ROSC). Secondary outcome: correlation of platelet mitochondrial bioenergetics to cerebral bioenergetic function. Platelet maximal oxidative phosphorylation (OXPHOSCI+CII), P respiration through Complex II (OXPHOSCII, P respiration was not due to uncoupling, as the LEAKCI + CII respiration (mitochondrial respiration independent of ATP-production) was unchanged after CA/ROSC. Larger increases in platelet mitochondrial respiratory control ratio (RCR) compared to pre-CA RCR were significantly correlated with lower RCRs in the cortex (P respiration. Platelet mitochondrial respiration is significantly increased four hours after ROSC. Future studies will identify mechanistic relationships between this serum biomarker and altered cerebral bioenergetics function following cardiac arrest.

  1. Hypoxia-Like Signatures Induced by BCR-ABL Potentially Alter the Glutamine Uptake for Maintaining Oxidative Phosphorylation.

    Directory of Open Access Journals (Sweden)

    Pallavi Sontakke

    Full Text Available The Warburg effect is probably the most prominent metabolic feature of cancer cells, although little is known about the underlying mechanisms and consequences. Here, we set out to study these features in detail in a number of leukemia backgrounds. The transcriptomes of human CB CD34+ cells transduced with various oncogenes, including BCR-ABL, MLL-AF9, FLT3-ITD, NUP98-HOXA9, STAT5A and KRASG12V were analyzed in detail. Our data indicate that in particular BCR-ABL, KRASG12V and STAT5 could impose hypoxic signaling under normoxic conditions. This coincided with an upregulation of glucose importers SLC2A1/3, hexokinases and HIF1 and 2. NMR-based metabolic profiling was performed in CB CD34+ cells transduced with BCR-ABL versus controls, both cultured under normoxia and hypoxia. Lactate and pyruvate levels were increased in BCR-ABL-expressing cells even under normoxia, coinciding with enhanced glutaminolysis which occurred in an HIF1/2-dependent manner. Expression of the glutamine importer SLC1A5 was increased in BCR-ABL+ cells, coinciding with an increased susceptibility to the glutaminase inhibitor BPTES. Oxygen consumption rates also decreased upon BPTES treatment, indicating a glutamine dependency for oxidative phosphorylation. The current study suggests that BCR-ABL-positive cancer cells make use of enhanced glutamine metabolism to maintain TCA cell cycle activity in glycolytic cells.

  2. Human Leukemic Cells performing Oxidative Phosphorylation (OXPHOS Generate an Antioxidant Response Independently of Reactive Oxygen species (ROS Production

    Directory of Open Access Journals (Sweden)

    Abrar Ul Haq Khan

    2016-01-01

    Full Text Available Tumor cell metabolism is altered during leukemogenesis. Cells performing oxidative phosphorylation (OXPHOS generate reactive oxygen species (ROS through mitochondrial activity. To limit the deleterious effects of excess ROS, certain gene promoters contain antioxidant response elements (ARE, e.g. the genes NQO-1 and HO-1. ROS induces conformational changes in KEAP1 and releases NRF2, which activates AREs. We show in vitro and in vivo that OXPHOS induces, both in primary leukemic cells and cell lines, de novo expression of NQO-1 and HO-1 and also the MAPK ERK5 and decreases KEAP1 mRNA. ERK5 activates the transcription factor MEF2, which binds to the promoter of the miR-23a–27a–24-2 cluster. Newly generated miR-23a destabilizes KEAP1 mRNA by binding to its 3′UTR. Lower KEAP1 levels increase the basal expression of the NRF2-dependent genes NQO-1 and HO-1. Hence, leukemic cells performing OXPHOS, independently of de novo ROS production, generate an antioxidant response to protect themselves from ROS.

  3. Insulin acutely improves mitochondrial function of rat and human skeletal muscle by increasing coupling efficiency of oxidative phosphorylation.

    Science.gov (United States)

    Nisr, Raid B; Affourtit, Charles

    2014-02-01

    Insulin is essential for the regulation of fuel metabolism and triggers the uptake of glucose by skeletal muscle. The imported glucose is either stored or broken down, as insulin stimulates glycogenesis and ATP synthesis. The mechanism by which ATP production is increased is incompletely understood at present and, generally, relatively little functional information is available on the effect of insulin on mitochondrial function. In this paper we have exploited extracellular flux technology to investigate insulin effects on the bioenergetics of rat (L6) and human skeletal muscle myoblasts and myotubes. We demonstrate that a 20-min insulin exposure significantly increases (i) the cell respiratory control ratio, (ii) the coupling efficiency of oxidative phosphorylation, and (iii) the glucose sensitivity of anaerobic glycolysis. The improvement of mitochondrial function is explained by an insulin-induced immediate decrease of mitochondrial proton leak. Palmitate exposure annuls the beneficial mitochondrial effects of insulin. Our data improve the mechanistic understanding of insulin-stimulated ATP synthesis, and reveal a hitherto undisclosed insulin sensitivity of cellular bioenergetics that suggests a novel way of detecting insulin responsiveness of cells. © 2013.

  4. Mitochondrial toxicity of selective COX-2 inhibitors via inhibition of oxidative phosphorylation (ATP synthesis) in rat liver mitochondria

    DEFF Research Database (Denmark)

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2016-01-01

    Cyclooxygenase-2 (COX-2) inhibitors (coxibs) are non-steroidal anti-inflammatory drugs (NSAIDs) designed to selectively inhibit COX-2. However, drugs of this therapeutic class are associated with drug induced liver injury (DILI) and mitochondrial injury is likely to play a role. The effects...... of selective COX-2 inhibitors on inhibition of oxidative phosphorylation (ATP synthesis) in rat liver mitochondria were investigated. The order of potency of inhibition of ATP synthesis was: lumiracoxib (IC50: 6.48 ± 2.74 μM)>celecoxib (IC50: 14.92 ± 6.40 μM)>valdecoxib (IC50: 161.4 ± 28.6 μM)>rofecoxib (IC50...... correlation (with r(2)=0.921) was observed between the potency of inhibition of ATP synthesis and the log P values. The in vitro metabolism of coxibs in rat liver mitochondria yielded for each drug substance a major single metabolite and identified a hydroxy metabolite with each of the coxibs...

  5. Silencing of PINK1 expression affects mitochondrial DNA and oxidative phosphorylation in dopaminergic cells.

    Directory of Open Access Journals (Sweden)

    Matthew E Gegg

    Full Text Available Mitochondrial dysfunction has been implicated in the pathogenesis of Parkinson's disease (PD. Impairment of the mitochondrial electron transport chain (ETC and an increased frequency in deletions of mitochondrial DNA (mtDNA, which encodes some of the subunits of the ETC, have been reported in the substantia nigra of PD brains. The identification of mutations in the PINK1 gene, which cause an autosomal recessive form of PD, has supported mitochondrial involvement in PD. The PINK1 protein is a serine/threonine kinase localized in mitochondria and the cytosol. Its precise function is unknown, but it is involved in neuroprotection against a variety of stress signalling pathways.In this report we have investigated the effect of silencing PINK1 expression in human dopaminergic SH-SY5Y cells by siRNA on mtDNA synthesis and ETC function. Loss of PINK1 expression resulted in a decrease in mtDNA levels and mtDNA synthesis. We also report a concomitant loss of mitochondrial membrane potential and decreased mitochondrial ATP synthesis, with the activity of complex IV of the ETC most affected. This mitochondrial dysfunction resulted in increased markers of oxidative stress under basal conditions and increased cell death following treatment with the free radical generator paraquat.This report highlights a novel function of PINK1 in mitochondrial biogenesis and a role in maintaining mitochondrial ETC activity. Dysfunction of both has been implicated in sporadic forms of PD suggesting that these may be key pathways in the development of the disease.

  6. Platelet content of nitric oxide synthase 3 phosphorylated at Serine 1177 is associated with the functional response of platelets to aspirin.

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    Javier Modrego

    Full Text Available OBJECTIVE: To analyse if platelet responsiveness to aspirin (ASA may be associated with a different ability of platelets to generate nitric oxide (NO. PATIENTS/METHODS: Platelets were obtained from 50 patients with stable coronary ischemia and were divided into ASA-sensitive (n = 26 and ASA-resistant (n = 24 using a platelet functionality test (PFA-100. RESULTS: ASA-sensitive platelets tended to release more NO (determined as nitrite + nitrate than ASA-resistant platelets but it did not reach statistical significance. Protein expression of nitric oxide synthase 3 (NOS3 was higher in ASA-sensitive than in ASA-resistant platelets but there were no differences in the platelet expression of nitric oxide synthase 2 (NOS2 isoform. The highest NOS3 expression in ASA-sensitive platelets was independent of the presence of T-to-C mutation at nucleotide position -786 (T(-786 → C in the NOS3-coding gene. However, platelet content of phosphorylated NOS3 at Serine (Ser(1177, an active form of NOS3, was higher in ASA-sensitive than in ASA-resistant platelets. The level of platelet NOS3 Ser(1177 phosphorylation was positively associated with the closure time in the PFA-100 test. In vitro, collagen failed to stimulate the aggregation of ASA-sensitive platelets, determined by lumiaggregometry, and it was associated with a significant increase (p = 0.018 of NOS3 phosphorylation at Ser(1177. On the contrary, collagen stimulated the aggregation of ASA-resistant platelets but did not significantly modify the platelet content of phosphorylated NOS3 Ser(1177. During collagen stimulation the release of NO from ASA-sensitive platelets was significantly enhanced but it was not modified in ASA-resistant platelets. CONCLUSIONS: Functional platelet responsiveness to ASA was associated with the platelet content of phosphorylated NOS3 at Ser(1177.

  7. Protein kinase Cα phosphorylates a novel argininosuccinate synthase site at serine 328 during calcium-dependent stimulation of endothelial nitric-oxide synthase in vascular endothelial cells.

    Science.gov (United States)

    Haines, Ricci J; Corbin, Karen D; Pendleton, Laura C; Eichler, Duane C

    2012-07-27

    Endothelial nitric-oxide synthase (eNOS) utilizes l-arginine as its principal substrate, converting it to l-citrulline and nitric oxide (NO). l-Citrulline is recycled to l-arginine by two enzymes, argininosuccinate synthase (AS) and argininosuccinate lyase, providing the substrate arginine for eNOS and NO production in endothelial cells. Together, these three enzymes, eNOS, AS, and argininosuccinate lyase, make up the citrulline-NO cycle. Although AS catalyzes the rate-limiting step in NO production, little is known about the regulation of AS in endothelial cells beyond the level of transcription. In this study, we showed that AS Ser-328 phosphorylation was coordinately regulated with eNOS Ser-1179 phosphorylation when bovine aortic endothelial cells were stimulated by either a calcium ionophore or thapsigargin to produce NO. Furthermore, using in vitro kinase assay, kinase inhibition studies, as well as protein kinase Cα (PKCα) knockdown experiments, we demonstrate that the calcium-dependent phosphorylation of AS Ser-328 is mediated by PKCα. Collectively, these findings suggest that phosphorylation of AS at Ser-328 is regulated in accordance with the calcium-dependent regulation of eNOS under conditions that promote NO production and are in keeping with the rate-limiting role of AS in the citrulline-NO cycle of vascular endothelial cells.

  8. L-Arginine Enhances Protein Synthesis by Phosphorylating mTOR (Thr 2446 in a Nitric Oxide-Dependent Manner in C2C12 Cells

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    Ruxia Wang

    2018-01-01

    Full Text Available Muscle atrophy may arise from many factors such as inactivity, malnutrition, and inflammation. In the present study, we investigated the stimulatory effect of nitric oxide (NO on muscle protein synthesis. Primarily, C2C12 cells were supplied with extra L-arginine (L-Arg in the culture media. L-Arg supplementation increased the activity of inducible nitric oxide synthase (iNOS, the rate of protein synthesis, and the phosphorylation of mTOR (Thr 2446 and p70S6K (Thr 389. L-NAME, an NOS inhibitor, decreased NO concentrations within cells and abolished the stimulatory effect of L-Arg on protein synthesis and the phosphorylation of mTOR and p70S6K. In contrast, SNP (sodium nitroprusside, an NO donor, increased NO concentrations, enhanced protein synthesis, and upregulated mTOR and p70S6K phosphorylation, regardless of L-NAME treatment. Blocking mTOR with rapamycin abolished the stimulatory effect of both L-Arg and SNP on protein synthesis and p70S6K phosphorylation. These results indicate that L-Arg stimulates protein synthesis via the activation of the mTOR (Thr 2446/p70S6K signaling pathway in an NO-dependent manner.

  9. Effect of testosterone on markers of mitochondrial oxidative phosphorylation and lipid metabolism in muscle of aging men with subnormal bioavailable testosterone

    DEFF Research Database (Denmark)

    Petersson, Stine J; Christensen, Louise L; Kristensen, Jonas M

    2014-01-01

    therapy on regulators of mitochondrial biogenesis and markers of OxPhos and lipid metabolism in the skeletal muscle of aging men with subnormal bioavailable testosterone levels. METHODS: Skeletal muscle biopsies were obtained before and after treatment with either testosterone gel (n=12) or placebo (n=13......) for 6 months. Insulin sensitivity and substrate oxidation were assessed by euglycemic-hyperinsulinemic clamp and indirect calorimetry. Muscle mRNA levels and protein abundance and phosphorylation of enzymes involved in mitochondrial biogenesis, OxPhos, and lipid metabolism were examined by quantitative......: The beneficial effect of testosterone treatment on lipid oxidation is not explained by increased abundance or phosphorylation-dependent activity of enzymes known to regulate mitochondrial biogenesis or markers of OxPhos and lipid metabolism in the skeletal muscle of aging men with subnormal bioavailable...

  10. Comparative analysis of respiratory chain and oxidative phosphorylation in Leishmania tarentolae, Crithidia fasciculata, Phytomonas serpens and procyclic stage of Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Verner, Zdeněk; Čermáková, P.; Škodová, Ingrid; Kováčová, B.; Lukeš, Julius; Horváth, A.

    2014-01-01

    Roč. 193, č. 1 (2014), s. 55-65 ISSN 0166-6851 R&D Projects: GA ČR GAP305/12/2261; GA MŠk(CZ) EE2.3.30.0032; GA MŠk LH12104 Institutional support: RVO:60077344 Keywords : mitochondrion * oxidative phosphorylation * Trypanosoma * Leishmania * Phytomonas * Crithidia Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.787, year: 2014

  11. Pulmonary Oxidative Stress, Inflammation and Cancer: Respirable Particulate Matter, Fibrous Dusts and Ozone as Major Causes of Lung Carcinogenesis through Reactive Oxygen Species Mechanisms

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    Spyridon Loridas

    2013-08-01

    Full Text Available Reactive oxygen or nitrogen species (ROS, RNS and oxidative stress in the respiratory system increase the production of mediators of pulmonary inflammation and initiate or promote mechanisms of carcinogenesis. The lungs are exposed daily to oxidants generated either endogenously or exogenously (air pollutants, cigarette smoke, etc.. Cells in aerobic organisms are protected against oxidative damage by enzymatic and non-enzymatic antioxidant systems. Recent epidemiologic investigations have shown associations between increased incidence of respiratory diseases and lung cancer from exposure to low levels of various forms of respirable fibers and particulate matter (PM, at occupational or urban air polluting environments. Lung cancer increases substantially for tobacco smokers due to the synergistic effects in the generation of ROS, leading to oxidative stress and inflammation with high DNA damage potential. Physical and chemical characteristics of particles (size, transition metal content, speciation, stable free radicals, etc. play an important role in oxidative stress. In turn, oxidative stress initiates the synthesis of mediators of pulmonary inflammation in lung epithelial cells and initiation of carcinogenic mechanisms. Inhalable quartz, metal powders, mineral asbestos fibers, ozone, soot from gasoline and diesel engines, tobacco smoke and PM from ambient air pollution (PM10 and PM2.5 are involved in various oxidative stress mechanisms. Pulmonary cancer initiation and promotion has been linked to a series of biochemical pathways of oxidative stress, DNA oxidative damage, macrophage stimulation, telomere shortening, modulation of gene expression and activation of transcription factors with important role in carcinogenesis. In this review we are presenting the role of ROS and oxidative stress in the production of mediators of pulmonary inflammation and mechanisms of carcinogenesis.

  12. EXPERIMENTAL SUBSTANTIATION OF PERMEABILIZED HEPATOCYTES MODEL FOR INVESTIGATION OF MITOCHONDRIA IN SITU RESPIRATION.

    Science.gov (United States)

    Merlavsky, V M; Manko, B O; Ikkert, O V; Manko, V V

    2015-01-01

    To verify experimentally the model of permeabilized hepatocytes, the degree of cell permeability was assessed using trypan blue and polarographycally determined cell respiration rate upon succinate (0.35 mM) and a-ketoglutarate (1 mM) oxidation. Oxidative phosphorylation was stimulated by ADP (750 μM). Hepatocyte permeabilization depends on digitonin concentraion in medium and on the number of cells in suspension. Thus, the permeabilization of 0.9-1.7 million cells/ml was completed by 25 μg/ml of digitonin, permeabilization of 2.0-3.0 million cells/ml--by 50 μg/ml of digitonin and permeabilization of 4.0-5.6 million cells/ml--by 100 μg/ml. Thus, the higher is the suspension density, the higher digitonin concentration is required. Treatment of hepatocytes with digitonin resulted in a decrease of endogenous respiration rate to a minimum upon 20-22 μg of digitonin per 1 million cells. Supplementation of permeabilized hepatocytes with α-ketoglutarate maintained stable respiration rate, on the level higher than endogenous respiration at the corresponding digitonin concentration, unlike the intact cells. Respiration rate of permeabilized hepatocytes at the simultaneous addition of α-ketoglutarate and ADP increased to the level of intact cell respiration, irrespective of digitonin concentration. Addition of solely succinate and especially succinate plus ADP markedly intensified the respiration of permeabilized hepatocytes to the level higher than that of intact cells. The dependence of succinate-stimulated respiration on digitonin concentration reached maximum at 20-22 αg of digitonin per 1 million cells. Optimal ratio of digitonin amount and the cell number in suspension is expected to be different in various tissues.

  13. Mitochondrial Respiration in Insulin-Producing β-Cells: General Characteristics and Adaptive Effects of Hypoxia.

    Science.gov (United States)

    Hals, Ingrid K; Bruerberg, Simon Gustafson; Ma, Zuheng; Scholz, Hanne; Björklund, Anneli; Grill, Valdemar

    2015-01-01

    To provide novel insights on mitochondrial respiration in β-cells and the adaptive effects of hypoxia. Insulin-producing INS-1 832/13 cells were exposed to 18 hours of hypoxia followed by 20-22 hours re-oxygenation. Mitochondrial respiration was measured by high-resolution respirometry in both intact and permeabilized cells, in the latter after establishing three functional substrate-uncoupler-inhibitor titration (SUIT) protocols. Concomitant measurements included proteins of mitochondrial complexes (Western blotting), ATP and insulin secretion. Intact cells exhibited a high degree of intrinsic uncoupling, comprising about 50% of oxygen consumption in the basal respiratory state. Hypoxia followed by re-oxygenation increased maximal overall respiration. Exploratory experiments in peremabilized cells could not show induction of respiration by malate or pyruvate as reducing substrates, thus glutamate and succinate were used as mitochondrial substrates in SUIT protocols. Permeabilized cells displayed a high capacity for oxidative phosphorylation for both complex I- and II-linked substrates in relation to maximum capacity of electron transfer. Previous hypoxia decreased phosphorylation control of complex I-linked respiration, but not in complex II-linked respiration. Coupling control ratios showed increased coupling efficiency for both complex I- and II-linked substrates in hypoxia-exposed cells. Respiratory rates overall were increased. Also previous hypoxia increased proteins of mitochondrial complexes I and II (Western blotting) in INS-1 cells as well as in rat and human islets. Mitochondrial effects were accompanied by unchanged levels of ATP, increased basal and preserved glucose-induced insulin secretion. Exposure of INS-1 832/13 cells to hypoxia, followed by a re-oxygenation period increases substrate-stimulated respiratory capacity and coupling efficiency. Such effects are accompanied by up-regulation of mitochondrial complexes also in pancreatic islets

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  15. Combining metal oxide affinity chromatography (MOAC and selective mass spectrometry for robust identification of in vivo protein phosphorylation sites

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    Weckwerth Wolfram

    2005-11-01

    Full Text Available Abstract Background Protein phosphorylation is accepted as a major regulatory pathway in plants. More than 1000 protein kinases are predicted in the Arabidopsis proteome, however, only a few studies look systematically for in vivo protein phosphorylation sites. Owing to the low stoichiometry and low abundance of phosphorylated proteins, phosphorylation site identification using mass spectrometry imposes difficulties. Moreover, the often observed poor quality of mass spectra derived from phosphopeptides results frequently in uncertain database hits. Thus, several lines of evidence have to be combined for a precise phosphorylation site identification strategy. Results Here, a strategy is presented that combines enrichment of phosphoproteins using a technique termed metaloxide affinity chromatography (MOAC and selective ion trap mass spectrometry. The complete approach involves (i enrichment of proteins with low phosphorylation stoichiometry out of complex mixtures using MOAC, (ii gel separation and detection of phosphorylation using specific fluorescence staining (confirmation of enrichment, (iii identification of phosphoprotein candidates out of the SDS-PAGE using liquid chromatography coupled to mass spectrometry, and (iv identification of phosphorylation sites of these enriched proteins using automatic detection of H3PO4 neutral loss peaks and data-dependent MS3-fragmentation of the corresponding MS2-fragment. The utility of this approach is demonstrated by the identification of phosphorylation sites in Arabidopsis thaliana seed proteins. Regulatory importance of the identified sites is indicated by conservation of the detected sites in gene families such as ribosomal proteins and sterol dehydrogenases. To demonstrate further the wide applicability of MOAC, phosphoproteins were enriched from Chlamydomonas reinhardtii cell cultures. Conclusion A novel phosphoprotein enrichment procedure MOAC was applied to seed proteins of A. thaliana and to

  16. Erection capability is potentiated by long-term sildenafil treatment: role of blood flow-induced endothelial nitric-oxide synthase phosphorylation.

    Science.gov (United States)

    Musicki, Biljana; Champion, Hunter C; Becker, Robyn E; Liu, Tongyun; Kramer, Melissa F; Burnett, Arthur L

    2005-07-01

    Despite demonstrated clinical efficacy of sildenafil for the temporary treatment of erectile dysfunction, the possibility that sildenafil used long-term durably augments erectile ability remains unclear. We investigated whether continuous long-term administration of sildenafil at clinically relevant levels to aged rats "primes" the penis for improved erectile ability and involves nitric oxide (NO) or RhoA/Rho-kinase signaling pathways. In aged, but not young rats, sildenafil prolonged erection and increased the protein expressions of phosphorylated endothelial NO synthase (eNOS) at serine-1177 and phosphorylated Akt at serine-473 in penes. Only in the young rat penis, protein expressions of phosphodiesterase-5 and phosphomyosin phosphatase target subunit 1, a marker of Rho-kinase activity, were increased by sildenafil. Sildenafil inhibited phosphodiesterase-5 activity in penes of young and aged rats coincident with assayed free plasma levels of the drug equivalent to clinically therapeutic measurements. We conclude that erectile ability can be enhanced under preconditions of erectile impairment by long-term inhibition of phosphodiesterase-5 and that the effect is mediated by Akt-dependent eNOS phosphorylation. The lack of erectile ability enhancement in young rats by long-term phosphodiesterase-5 inhibition may relate to restrained NO signaling by phosphodiesterase-5 up-regulation, lack of incremental Akt and eNOS phosphorylation, and heightened Rho-kinase signaling in the penis.

  17. Tobacco Smoke: Involvement of Reactive Oxygen Species and Stable Free Radicals in Mechanisms of Oxidative Damage, Carcinogenesis and Synergistic Effects with Other Respirable Particles

    Directory of Open Access Journals (Sweden)

    Konstantinos Fiotakis

    2009-02-01

    Full Text Available Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR and spin- trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2·- and hydroxyl (HO· radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2’-deoxyguanosine (a biomarker for carcinogenesis.Also, we observed synergistic effects in the generation of HO·, through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc. and ambient particulate matter (PM, such as PM10, PM2.5 and diesel exhaust particles (DEP. The highest synergistic effects was observed with the asbestos fibres (freshly grounded, PM2.5 and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and “bio-filters” with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase.

  18. Tobacco Smoke: Involvement of Reactive Oxygen Species and Stable Free Radicals in Mechanisms of Oxidative Damage, Carcinogenesis and Synergistic Effects with Other Respirable Particles

    Science.gov (United States)

    Valavanidis, Athanasios; Vlachogianni, Thomais; Fiotakis, Konstantinos

    2009-01-01

    Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS) in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR) and spin-trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2•−) and hydroxyl (HO•) radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT) solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2’-deoxyguanosine (a biomarker for carcinogenesis). Also, we observed synergistic effects in the generation of HO•, through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc.) and ambient particulate matter (PM), such as PM10, PM2.5 and diesel exhaust particles (DEP). The highest synergistic effects was observed with the asbestos fibres (freshly grounded), PM2.5 and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and “bio-filters” with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase. PMID:19440393

  19. [State of mitochondrial respiration and calcium capacity in livers of rats with different resistance to hypoxia after injections of L-arginine].

    Science.gov (United States)

    Kurhaliuk, N M

    2001-01-01

    In experiments on rats with different resistance to hypoxia are investigated processes of mitochondrial respiration, oxidative phosphorylation and calcium capacity in liver under precursor nitric oxide L-arginine (600 mg/kg) and blockator nitric oxide synthase L-NNA (35 mg/kg) injections. We are used next substrates of oxidation: 0.35 mM succinate, 1 mM alpha-ketoglutarate, 1 mM alpha-ketoglutarate and 2 mM malonic acid. Increasing of ADP-stimulation respiration states under exogenous L-arginine injection, decreasing efficacy of respiration processes (respiration control on Chance and ADP/O) under such substrates oxidation, testify to oxide energy support decreasing and reversing nitric oxide inhibit in such conditions. This will be used as mechanism cell regulation succinate dehydrogenase activity. It has shown that L-arginine injection increase calcium mitochondrial capacity low resistance to hypoxia rats using substrates of oxidation succinate and alpha-ketoglutarate to control meanings of high resistance rats. Effects of nitric oxide precursor influence on this processes limit NO-synthase inhibitor L-NNA.

  20. Phosphorylation of Icariin Can Alleviate the Oxidative Stress Caused by the Duck Hepatitis Virus A through Mitogen-Activated Protein Kinases Signaling Pathways

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    Wen Xiong

    2017-09-01

    Full Text Available The duck virus hepatitis (DVH caused by the duck hepatitis virus A (DHAV has produced extensive economic losses to the duck industry. The currently licensed commercial vaccine has shown some defects and does not completely prevent the DVH. Accordingly, a new alternative treatment for this disease is urgently needed. Previous studies have shown that icariin (ICA and its phosphorylated derivative (pICA possessed good anti-DHAV effects through direct and indirect antiviral pathways, such as antioxidative stress. But the antioxidant activity showed some differences between ICA and pICA. The aim of this study is to prove that ICA and pICA attenuate oxidative stress caused by DHAV in vitro and in vivo, and to investigate their mechanism of action to explain their differences in antioxidant activities. In vivo, the dynamic deaths, oxidative evaluation indexes and hepatic pathological change scores were detected. When was added the hinokitiol which showed the pro-oxidative effect as an intervention method, pICA still possessed more treatment effect than ICA. The strong correlation between mortality and oxidative stress proves that ICA and pICA alleviate oxidative stress caused by DHAV. This was also demonstrated by the addition of hydrogen peroxide (H2O2 as an intervention method in vitro. pICA can be more effective than ICA to improve duck embryonic hepatocytes (DEHs viability and reduce the virulence of DHAV. The strong correlation between TCID50 and oxidative stress demonstrates that ICA and pICA can achieve anti-DHAV effects by inhibiting oxidative stress. In addition, the superoxide dismutase (SOD and glutathione peroxidase (GSH-Px of ICA and pICA showed significant difference. pICA could significantly inhibit the phosphorylation of p38, extra cellular signal regulated Kinase (ERK 1/2 and c-Jun N-terminal kinase (JNK, which were related to mitogen-activated protein kinases (MAPKs signaling pathways. Ultimately, compared to ICA, pICA exhibited more

  1. Oxidative phosphorylation is essential for felid sperm function, but is substantially lower in cheetah (Acinonyx jubatus) compared to domestic cat (Felis catus) ejaculate.

    Science.gov (United States)

    Terrell, Kimberly A; Wildt, David E; Anthony, Nicola M; Bavister, Barry D; Leibo, S P; Penfold, Linda M; Marker, Laurie L; Crosier, Adrienne E

    2011-09-01

    Compared with the normospermic domestic cat, sperm metabolic function is compromised in the teratospermic cat and cheetah, but the pathway(s) involved in this deficiency are unknown. Glycolysis is essential for sperm motility, yet it appears to function normally in spermatozoa of either species regardless of structural morphology. We conducted a comparative study to further understand the mechanisms of energy production in felid spermatozoa, with the hypothesis that oxidative phosphorylation is required for normal sperm function and is impaired in teratospermic ejaculates. Electroejaculates from both species were stained with MitoTracker to quantify mitochondrial membrane potential (MMP) or were incubated to assess changes in sperm function (motility, acrosomal integrity, and lactate production) after mitochondrial inhibition with myxothiazol. Sperm midpiece dimensions also were quantified. Sperm mitochondrial fluorescence (directly proportional to MMP) was ~95% lower in the cheetah compared with the normospermic and teratospermic cat, despite the cheetah having a 10% longer midpiece. In both species, MMP was increased 5-fold in spermatozoa with retained cytoplasm compared with structurally normal cells. Inhibition of oxidative phosphorylation impaired sperm function in both species, but a 100-fold higher inhibitor concentration was required in the cat compared with the cheetah. Collectively, findings revealed that oxidative phosphorylation was required for sperm function in the domestic cat and cheetah. This pathway of energy production appeared markedly less active in the cheetah, indicating a species-specific vulnerability to mitochondrial dysfunction. The unexpected, cross-species linkage between retained cytoplasmic droplets and elevated MMP may reflect increased concentrations of metabolic enzymes or substrates in these structures.

  2. Lymphocyte-specific protein tyrosine kinase (Lck) interacts with CR6-interacting factor 1 (CRIF1) in mitochondria to repress oxidative phosphorylation

    International Nuclear Information System (INIS)

    Vahedi, Shahrooz; Chueh, Fu-Yu; Chandran, Bala; Yu, Chao-Lan

    2015-01-01

    Many cancer cells exhibit reduced mitochondrial respiration as part of metabolic reprogramming to support tumor growth. Mitochondrial localization of several protein tyrosine kinases is linked to this characteristic metabolic shift in solid tumors, but remains largely unknown in blood cancer. Lymphocyte-specific protein tyrosine kinase (Lck) is a key T-cell kinase and widely implicated in blood malignancies. The purpose of our study is to determine whether and how Lck contributes to metabolic shift in T-cell leukemia through mitochondrial localization. We compared the human leukemic T-cell line Jurkat with its Lck-deficient derivative Jcam cell line. Differences in mitochondrial respiration were measured by the levels of mitochondrial membrane potential, oxygen consumption, and mitochondrial superoxide. Detailed mitochondrial structure was visualized by transmission electron microscopy. Lck localization was evaluated by subcellular fractionation and confocal microscopy. Proteomic analysis was performed to identify proteins co-precipitated with Lck in leukemic T-cells. Protein interaction was validated by biochemical co-precipitation and confocal microscopy, followed by in situ proximity ligation assay microscopy to confirm close-range (<16 nm) interaction. Jurkat cells have abnormal mitochondrial structure and reduced levels of mitochondrial respiration, which is associated with the presence of mitochondrial Lck and lower levels of mitochondrion-encoded electron transport chain proteins. Proteomics identified CR6-interacting factor 1 (CRIF1) as the novel Lck-interacting protein. Lck association with CRIF1 in Jurkat mitochondria was confirmed biochemically and by microscopy, but did not lead to CRIF1 tyrosine phosphorylation. Consistent with the role of CRIF1 in functional mitoribosome, shRNA-mediated silencing of CRIF1 in Jcam resulted in mitochondrial dysfunction similar to that observed in Jurkat. Reduced interaction between CRIF1 and Tid1, another key component

  3. The cellular and compartmental profile of mouse retinal glycolysis, tricarboxylic acid cycle, oxidative phosphorylation, and ~P transferring kinases.

    Science.gov (United States)

    Rueda, Elda M; Johnson, Jerry E; Giddabasappa, Anand; Swaroop, Anand; Brooks, Matthew J; Sigel, Irena; Chaney, Shawnta Y; Fox, Donald A

    2016-01-01

    The homeostatic regulation of cellular ATP is achieved by the coordinated activity of ATP utilization, synthesis, and buffering. Glucose is the major substrate for ATP synthesis through glycolysis and oxidative phosphorylation (OXPHOS), whereas intermediary metabolism through the tricarboxylic acid (TCA) cycle utilizes non-glucose-derived monocarboxylates, amino acids, and alpha ketoacids to support mitochondrial ATP and GTP synthesis. Cellular ATP is buffered by specialized equilibrium-driven high-energy phosphate (~P) transferring kinases. Our goals were twofold: 1) to characterize the gene expression, protein expression, and activity of key synthesizing and regulating enzymes of energy metabolism in the whole mouse retina, retinal compartments, and/or cells and 2) to provide an integrative analysis of the results related to function. mRNA expression data of energy-related genes were extracted from our whole retinal Affymetrix microarray data. Fixed-frozen retinas from adult C57BL/6N mice were used for immunohistochemistry, laser scanning confocal microscopy, and enzymatic histochemistry. The immunoreactivity levels of well-characterized antibodies, for all major retinal cells and their compartments, were obtained using our established semiquantitative confocal and imaging techniques. Quantitative cytochrome oxidase (COX) and lactate dehydrogenase (LDH) activity was determined histochemically. The Affymetrix data revealed varied gene expression patterns of the ATP synthesizing and regulating enzymes found in the muscle, liver, and brain. Confocal studies showed differential cellular and compartmental distribution of isozymes involved in glucose, glutamate, glutamine, lactate, and creatine metabolism. The pattern and intensity of the antibodies and of the COX and LDH activity showed the high capacity of photoreceptors for aerobic glycolysis and OXPHOS. Competition assays with pyruvate revealed that LDH-5 was localized in the photoreceptor inner segments. The

  4. Nitric oxide generated by ionizing radiation and EGF is implicated in EGF receptor phosphorylation in A549 lung carcinoma cells

    International Nuclear Information System (INIS)

    Park, In Chul; Lee, Hyung Chahn; Rhee, Chang Hun; Hong, Seok Il

    2004-01-01

    Although it has been demonstrated that ionizing radiation (IR) control various cell functions in a different cell types, the mechanisms of its action via NO are not well understood. NO may potentially affect every type of mammalian cells, owing to its ubiquitous production and participate in the control of cell proliferation in a great variety of cell types. The epidermal growth factor (EGF) receptor is a transmembrane glycoprotein of Mr 170,000. When EGF binds to its receptor, the receptor is dimerized and autophosphorylated at the carboxyl-terminal tyrosine 992, 1608, 1086, 1148 and 1173. This phosphorylated receptor initiates a series of signal tranduction events through interacting proteins of SH2 family including Shc, Grb2 and Sos, which in turn trigger ativation of MAPK cascades. Although the number of signaling events mediated by IR-induced NO is growing, it is still unclear how NO activate cellular signaling events. Thus, we examined the effect of NO on cellular phosphorylation and found that NO was produced by ionizing radiation in A549 lung adenocarcinoma cells and enhances the unique tyrosine phosphorylation on EGF receptor

  5. Overexpression of pig selenoprotein S blocks OTA-induced promotion of PCV2 replication by inhibiting oxidative stress and p38 phosphorylation in PK15 cells

    Science.gov (United States)

    Gan, Fang; Hu, Zhihua; Huang, Yu; Xue, Hongxia; Huang, Da; Qian, Gang; Hu, Junfa; Chen, Xingxiang; Wang, Tian; Huang, Kehe

    2016-01-01

    Porcine circovirus type 2 (PCV2) is the primary cause of porcine circovirus disease, and ochratoxin A (OTA)-induced oxidative stress promotes PCV2 replication. In humans, selenoprotein S (SelS) has antioxidant ability, but it is unclear whether SelS affects viral infection. Here, we stably transfected PK15 cells with pig pCDNA3.1-SelS to overexpress SelS. Selenium (Se) at 2 or 4 μM and SelS overexpression blocked the OTA-induced increases of PCV2 DNA copy number and infected cell numbers. SelS overexpression also increased glutathione (GSH), NF-E2-related factor 2 (Nrf2) mRNA, and γ-glutamyl-cysteine synthetase mRNA levels; decreased reactive oxygen species (ROS) levels; and inhibited p38 phosphorylation in PCV2-infected PK15 cells, regardless of OTA treatment. Buthionine sulfoximine reversed all of the above SelS-induced changes. siRNA-mediated SelS knockdown decreased Nrf2 mRNA and GSH levels, increased ROS levels, and promoted PCV2 replication in OTA-treated PK15 cells. These data indicate that pig SelS blocks OTA-induced promotion of PCV2 replication by inhibiting the oxidative stress and p38 phosphorylation in PK15 cells. PMID:26943035

  6. The HK2 Dependent “Warburg Effect” and Mitochondrial Oxidative Phosphorylation in Cancer: Targets for Effective Therapy with 3-Bromopyruvate

    Directory of Open Access Journals (Sweden)

    Paweł Lis

    2016-12-01

    Full Text Available This review summarizes the current state of knowledge about the metabolism of cancer cells, especially with respect to the “Warburg” and “Crabtree” effects. This work also summarizes two key discoveries, one of which relates to hexokinase-2 (HK2, a major player in both the “Warburg effect” and cancer cell immortalization. The second discovery relates to the finding that cancer cells, unlike normal cells, derive as much as 60% of their ATP from glycolysis via the “Warburg effect”, and the remaining 40% is derived from mitochondrial oxidative phosphorylation. Also described are selected anticancer agents which generally act as strong energy blockers inside cancer cells. Among them, much attention has focused on 3-bromopyruvate (3BP. This small alkylating compound targets both the “Warburg effect”, i.e., elevated glycolysis even in the presence oxygen, as well as mitochondrial oxidative phosphorylation in cancer cells. Normal cells remain unharmed. 3BP rapidly kills cancer cells growing in tissue culture, eradicates tumors in animals, and prevents metastasis. In addition, properly formulated 3BP shows promise also as an effective anti-liver cancer agent in humans and is effective also toward cancers known as “multiple myeloma”. Finally, 3BP has been shown to significantly extend the life of a human patient for which no other options were available. Thus, it can be stated that 3BP is a very promising new anti-cancer agent in the process of undergoing clinical development.

  7. JNK Phosphorylates SIRT6 to Stimulate DNA Double-Strand Break Repair in Response to Oxidative Stress by Recruiting PARP1 to DNA Breaks

    Directory of Open Access Journals (Sweden)

    Michael Van Meter

    2016-09-01

    Full Text Available The accumulation of damage caused by oxidative stress has been linked to aging and to the etiology of numerous age-related diseases. The longevity gene, sirtuin 6 (SIRT6, promotes genome stability by facilitating DNA repair, especially under oxidative stress conditions. Here we uncover the mechanism by which SIRT6 is activated by oxidative stress to promote DNA double-strand break (DSB repair. We show that the stress-activated protein kinase, c-Jun N-terminal kinase (JNK, phosphorylates SIRT6 on serine 10 in response to oxidative stress. This post-translational modification facilitates the mobilization of SIRT6 to DNA damage sites and is required for efficient recruitment of poly (ADP-ribose polymerase 1 (PARP1 to DNA break sites and for efficient repair of DSBs. Our results demonstrate a post-translational mechanism regulating SIRT6, and they provide the link between oxidative stress signaling and DNA repair pathways that may be critical for hormetic response and longevity assurance.

  8. Methylene blue improves mitochondrial respiration and decreases oxidative stress in a substrate-dependent manner in diabetic rat hearts.

    Science.gov (United States)

    Duicu, Oana M; Privistirescu, Andreea; Wolf, Adrian; Petruş, Alexandra; Dănilă, Maria D; Raţiu, Corina D; Muntean, Danina M; Sturza, Adrian

    2017-11-01

    Diabetic cardiomyopathy has been systematically associated with compromised mitochondrial energetics and increased generation of reactive oxygen species (ROS) that underlie its progression to heart failure. Methylene blue is a redox drug with reported protective effects mainly on brain mitochondria. The purpose of the present study was to characterize the effects of acute administration of methylene blue on mitochondrial respiration, H 2 O 2 production, and calcium sensitivity in rat heart mitochondria isolated from healthy and 2 months (streptozotocin-induced) diabetic rats. Mitochondrial respiratory function was assessed by high-resolution respirometry. H 2 O 2 production and calcium retention capacity were measured spectrofluorimetrically. The addition of methylene blue (0.1 μmol·L -1 ) elicited an increase in oxygen consumption of mitochondria energized with complex I and II substrates in both normal and diseased mitochondria. Interestingly, methylene blue elicited a significant increase in H 2 O 2 release in the presence of complex I substrates (glutamate and malate), but had an opposite effect in mitochondria energized with complex II substrate (succinate). No changes in the calcium retention capacity of healthy or diabetic mitochondria were found in the presence of methylene blue. In conclusion, in cardiac mitochondria isolated from diabetic and nondiabetic rat hearts, methylene blue improved respiratory function and elicited a dichotomic, substrate-dependent effect on ROS production.

  9. The impact of respiration and oxidative stress response on recombinant α-amylase production by Saccharomyces cerevisiae.

    Science.gov (United States)

    Martínez, José L; Meza, Eugenio; Petranovic, Dina; Nielsen, Jens

    2016-12-01

    Studying protein production is important for fundamental research on cell biology and applied research for biotechnology. Yeast Saccharomyces cerevisiae is an attractive workhorse for production of recombinant proteins as it does not secrete many endogenous proteins and it is therefore easy to purify a secreted product. However, recombinant production at high rates represents a significant metabolic burden for the yeast cells, which results in oxidative stress and ultimately affects the protein production capacity. Here we describe a method to reduce the overall oxidative stress by overexpressing the endogenous HAP1 gene in a S. cerevisiae strain overproducing recombinant α-amylase. We demonstrate how Hap1p can activate a set of oxidative stress response genes and meanwhile contribute to increase the metabolic rate of the yeast strains, therefore mitigating the negative effect of the ROS accumulation associated to protein folding and hence increasing the production capacity during batch fermentations.

  10. The impact of respiration and oxidative stress response on recombinant α-amylase production by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Martinez Ruiz, José Luis; Meza, Eugenio; Petranovic, Dina

    2016-01-01

    by overexpressing the endogenous HAP1 gene in a S. cerevisiae strain overproducing recombinant α-amylase. We demonstrate how Hap1p can activate a set of oxidative stress response genes and meanwhile contribute to increase the metabolic rate of the yeast strains, therefore mitigating the negative effect of the ROS...

  11. Mitochondrial respiration and ROS emission during β-oxidation in the heart: An experimental-computational study.

    Science.gov (United States)

    Cortassa, Sonia; Sollott, Steven J; Aon, Miguel A

    2017-06-01

    Lipids are main fuels for cellular energy and mitochondria their major oxidation site. Yet unknown is to what extent the fuel role of lipids is influenced by their uncoupling effects, and how this affects mitochondrial energetics, redox balance and the emission of reactive oxygen species (ROS). Employing a combined experimental-computational approach, we comparatively analyze β-oxidation of palmitoyl CoA (PCoA) in isolated heart mitochondria from Sham and streptozotocin (STZ)-induced type 1 diabetic (T1DM) guinea pigs (GPs). Parallel high throughput measurements of the rates of oxygen consumption (VO2) and hydrogen peroxide (H2O2) emission as a function of PCoA concentration, in the presence of L-carnitine and malate, were performed. We found that PCoA concentration PCoA > 600 nmol/mg mito prot, in both control and diabetic animals. Also, for the first time, we show that an integrated two compartment mitochondrial model of β-oxidation of long-chain fatty acids and main energy-redox processes is able to simulate the relationship between VO2 and H2O2 emission as a function of lipid concentration. Model and experimental results indicate that PCoA oxidation and its concentration-dependent uncoupling effect, together with a partial lipid-dependent decrease in the rate of superoxide generation, modulate H2O2 emission as a function of VO2. Results indicate that keeping low levels of intracellular lipid is crucial for mitochondria and cells to maintain ROS within physiological levels compatible with signaling and reliable energy supply.

  12. Far-infrared radiation acutely increases nitric oxide production by increasing Ca2+ mobilization and Ca2+/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

    International Nuclear Information System (INIS)

    Park, Jung-Hyun; Lee, Sangmi; Cho, Du-Hyong; Park, Young Mi; Kang, Duk-Hee; Jo, Inho

    2013-01-01

    Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser 1179 phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser 1179 phosphorylation. •FIR increases intracellular Ca 2+ levels. •Thermo-sensitive TRPV Ca 2+ channels are unlikely to be involved in the FIR-mediated eNOS-Ser 1179 phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser 1179 ) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca 2+ levels. Treatment with KN-93, a selective inhibitor of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser 1179 phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser 1179 phosphorylation. This study suggests that FIR radiation increases NO

  13. Far-infrared radiation acutely increases nitric oxide production by increasing Ca{sup 2+} mobilization and Ca{sup 2+}/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung-Hyun; Lee, Sangmi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Cho, Du-Hyong [Department of Neuroscience, School of Medicine, Konkuk University, Seoul 143-701 (Korea, Republic of); Park, Young Mi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Kang, Duk-Hee [Division of Nephrology, Department of Internal Medicine, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Jo, Inho, E-mail: inhojo@ewha.ac.kr [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of)

    2013-07-12

    Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser{sup 1179} phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser{sup 1179} phosphorylation. •FIR increases intracellular Ca{sup 2+} levels. •Thermo-sensitive TRPV Ca{sup 2+} channels are unlikely to be involved in the FIR-mediated eNOS-Ser{sup 1179} phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser{sup 1179}) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca{sup 2+} levels. Treatment with KN-93, a selective inhibitor of Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. This

  14. Hyperthyroidism stimulates mitochondrial proton leak and ATP turnover in rat hepatocytes but does not change the overall kinetics of substrate oxidation reactions.

    Science.gov (United States)

    Harper, M E; Brand, M D

    1994-08-01

    Thyroid hormones have well-known effects on oxidative phosphorylation, but there is little quantitative information on their important sites of action. We have used top-down elasticity analysis, an extension of metabolic control analysis, to identify the sites of action of thyroid hormones on oxidative phosphorylation in rat hepatocytes. We divided the oxidative phosphorylation system into three blocks of reactions: the substrate oxidation subsystem, the phosphorylating subsystem, and the mitochondrial proton leak subsystem and have identified those blocks of reactions whose kinetics are significantly changed by hyperthyroidism. Our results show significant effects on the kinetics of the proton leak and the phosphorylating subsystems. Quantitative analyses revealed that 43% of the increase in resting respiration rate in hyperthyroid hepatocytes compared with euthyroid hepatocytes was due to differences in the proton leak and 59% was due to differences in the activity of the phosphorylating subsystem. There were no significant effects on the substrate oxidation subsystem. Changes in nonmitochondrial oxygen consumption accounted for -2% of the change in respiration rate. Top-down control analysis revealed that the distribution of control over the rates of mitochondrial oxygen consumption, ATP synthesis and consumption, and proton leak and over mitochondrial membrane potential (delta psi m) was similar in hepatocytes from hyperthyroid and littermate-paired euthyroid controls. The results of this study include the first complete top-down elasticity and control analyses of oxidative phosphorylation in hepatocytes from hyperthyroid rats.

  15. Glycolysis and mitochondrial respiration in mouse LDHC-null sperm.

    Science.gov (United States)

    Odet, Fanny; Gabel, Scott; London, Robert E; Goldberg, Erwin; Eddy, Edward M

    2013-04-01

    We demonstrated previously that a knockout (KO) of the lactate dehydrogenase type C (Ldhc) gene disrupted male fertility and caused a considerable reduction in sperm glucose consumption, ATP production, and motility. While that study used mice with a mixed genetic background, the present study used C57BL/6 (B6) and 129S6 (129) Ldhc KO mice. We found that B6 KO males were subfertile and 129 KO males were infertile. Sperm from 129 wild-type (WT) mice have a lower glycolytic rate than sperm from B6 WT mice, resulting in a greater reduction in ATP production in 129 KO sperm than in B6 KO sperm. The lower glycolytic rate in 129 sperm offered a novel opportunity to examine the role of mitochondrial respiration in sperm ATP production and motility. We observed that in media containing a mitochondrial substrate (pyruvate or lactate) as the sole energy source, ATP levels and progressive motility in 129 KO sperm were similar to those in 129 WT sperm. However, when glucose was added, lactate was unable to maintain ATP levels or progressive motility in 129 KO sperm. The rate of respiration (ZO2) was high when 129 KO or WT sperm were incubated with lactate alone, but addition of glucose caused a reduction in ZO2. These results indicate that in the absence of glucose, 129 sperm can produce ATP via oxidative phosphorylation, but in the presence of glucose, oxidative phosphorylation is suppressed and the sperm utilize aerobic glycolysis, a phenomenon known as the Crabtree effect.

  16. Biochemistry of storage lesions of red cell and platelet concentrates: A continuous fight implying oxidative/nitrosative/phosphorylative stress and signaling.

    Science.gov (United States)

    Rinalducci, Sara; Zolla, Lello

    2015-06-01

    The mechanisms responsible for the reduced lifespan of transfused red blood cells (RBCs) and platelets (PLTs) are still under investigation, however one explanation refers to the detrimental biochemical changes occurring during ex vivo storage of these blood products. A myriad of historical and more recent studies has contributed to advance our understanding of storage lesion. Without any doubts, proteomics had great impact on transfusion medicine by profiling the storage-dependent changes in the total detectable protein pool of both RBCs and PLTs. This review article focuses on the role of oxidative/nitrosative stress in developing RBC and PLT storage lesions, with a special glance at its biochemistry and cross-talk with phosphorylative signal transduction. In this sense, we enlighten the potential contribution of new branches of proteomics in identifying novel points of intervention for the improvement of blood product quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Transferrin receptor regulates pancreatic cancer growth by modulating mitochondrial respiration and ROS generation

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Seung Min, E-mail: smjeong@catholic.ac.kr [Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Hwang, Sunsook; Seong, Rho Hyun [School of Biological Sciences and Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2016-03-11

    The transferrin receptor (TfR1) is upregulated in malignant cells and its expression is associated with cancer progression. Because of its pre-eminent role in cell proliferation, TfR1 has been an important target for the development of cancer therapy. Although TfR1 is highly expressed in pancreatic cancers, what it carries out in these refractory cancers remains poorly understood. Here we report that TfR1 supports mitochondrial respiration and ROS production in human pancreatic ductal adenocarcinoma (PDAC) cells, which is required for their tumorigenic growth. Elevated TfR1 expression in PDAC cells contributes to oxidative phosphorylation, which allows for the generation of ROS. Importantly, mitochondrial-derived ROS are essential for PDAC growth. However, exogenous iron supplement cannot rescue the defects caused by TfR1 knockdown. Moreover, we found that TfR1 expression determines PDAC cells sensitivity to oxidative stress. Together, our findings reveal that TfR1 can contribute to the mitochondrial respiration and ROS production, which have essential roles in growth and survival of pancreatic cancer. - Highlights: • Pancreatic ductal adenocarcinoma (PDAC) exhibits an elevated transferrin receptor (TfR1) expression in comparison with non-transformed pancreatic cells. • TfR1 is required for PDAC growth by regulating mitochondrial respiration and ROS production. • TfR1 functions as a determinant of cell viability to oxidative stress in PDAC cells.

  18. Transferrin receptor regulates pancreatic cancer growth by modulating mitochondrial respiration and ROS generation

    International Nuclear Information System (INIS)

    Jeong, Seung Min; Hwang, Sunsook; Seong, Rho Hyun

    2016-01-01

    The transferrin receptor (TfR1) is upregulated in malignant cells and its expression is associated with cancer progression. Because of its pre-eminent role in cell proliferation, TfR1 has been an important target for the development of cancer therapy. Although TfR1 is highly expressed in pancreatic cancers, what it carries out in these refractory cancers remains poorly understood. Here we report that TfR1 supports mitochondrial respiration and ROS production in human pancreatic ductal adenocarcinoma (PDAC) cells, which is required for their tumorigenic growth. Elevated TfR1 expression in PDAC cells contributes to oxidative phosphorylation, which allows for the generation of ROS. Importantly, mitochondrial-derived ROS are essential for PDAC growth. However, exogenous iron supplement cannot rescue the defects caused by TfR1 knockdown. Moreover, we found that TfR1 expression determines PDAC cells sensitivity to oxidative stress. Together, our findings reveal that TfR1 can contribute to the mitochondrial respiration and ROS production, which have essential roles in growth and survival of pancreatic cancer. - Highlights: • Pancreatic ductal adenocarcinoma (PDAC) exhibits an elevated transferrin receptor (TfR1) expression in comparison with non-transformed pancreatic cells. • TfR1 is required for PDAC growth by regulating mitochondrial respiration and ROS production. • TfR1 functions as a determinant of cell viability to oxidative stress in PDAC cells.

  19. Preservation Analysis of Macrophage Gene Coexpression Between Human and Mouse Identifies PARK2 as a Genetically Controlled Master Regulator of Oxidative Phosphorylation in Humans

    Directory of Open Access Journals (Sweden)

    Veronica Codoni

    2016-10-01

    Full Text Available Macrophages are key players involved in numerous pathophysiological pathways and an in-depth characterization of their gene regulatory networks can help in better understanding how their dysfunction may impact on human diseases. We here conducted a cross-species network analysis of macrophage gene expression data between human and mouse to identify conserved networks across both species, and assessed whether such networks could reveal new disease-associated regulatory mechanisms. From a sample of 684 individuals processed for genome-wide macrophage gene expression profiling, we identified 27 groups of coexpressed genes (modules. Six modules were found preserved (P < 10−4 in macrophages from 86 mice of the Hybrid Mouse Diversity Panel. One of these modules was significantly [false discovery rate (FDR = 8.9 × 10−11] enriched for genes belonging to the oxidative phosphorylation (OXPHOS pathway. This pathway was also found significantly (FDR < 10−4 enriched in susceptibility genes for Alzheimer, Parkinson, and Huntington diseases. We further conducted an expression quantitative trait loci analysis to identify SNP that could regulate macrophage OXPHOS gene expression in humans. This analysis identified the PARK2 rs192804963 as a trans-acting variant influencing (minimal P-value = 4.3 × 10−8 the expression of most OXPHOS genes in humans. Further experimental work demonstrated that PARK2 knockdown expression was associated with increased OXPHOS gene expression in THP1 human macrophages. This work provided strong new evidence that PARK2 participates to the regulatory networks associated with oxidative phosphorylation and suggested that PARK2 genetic variations could act as a trans regulator of OXPHOS gene macrophage expression in humans.

  20. Hepatocytes Determine the Hypoxic Microenvironment and Radiosensitivity of Colorectal Cancer Cells Through Production of Nitric Oxide That Targets Mitochondrial Respiration

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Heng; Verovski, Valeri N.; Leonard, Wim; Law, Ka Lun; Vermeersch, Marieke; Storme, Guy; Van den Berge, Dirk; Gevaert, Thierry; Sermeus, Alexandra [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium); De Ridder, Mark, E-mail: mark.deridder@uzbrussel.be [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium)

    2013-03-01

    Purpose: To determine whether host hepatocytes may reverse hypoxic radioresistance through nitric oxide (NO)-induced oxygen sparing, in a model relevant to colorectal cancer (CRC) liver metastases. Methods and Materials: Hepatocytes and a panel of CRC cells were incubated in a tissue-mimetic coculture system with diffusion-limited oxygenation, and oxygen levels were monitored by an oxygen-sensing fluorescence probe. To activate endogenous NO production, cocultures were exposed to a cytokine mixture, and the expression of inducible nitric oxide synthase was analyzed by reverse transcription–polymerase chain reaction, Western blotting, and NO/nitrite production. The mitochondrial targets of NO were examined by enzymatic activity. To assess hypoxic radioresponse, cocultures were irradiated and reseeded for colonies. Results: Resting hepatocytes consumed 10-40 times more oxygen than mouse CT26 and human DLD-1, HT29, HCT116, and SW480 CRC cells, and thus seemed to be the major effectors of hypoxic conditioning. As a result, hepatocytes caused uniform radioprotection of tumor cells at a 1:1 ratio. Conversely, NO-producing hepatocytes radiosensitized all CRC cell lines more than 1.5-fold, similar to the effect of selective mitochondrial inhibitors. The radiosensitizing effect was associated with a respiratory self-arrest of hepatocytes at the level of aconitase and complex II, which resulted in profound reoxygenation of tumor cells through oxygen sparing. Nitric oxide–producing hepatocytes were at least 10 times more active than NO-producing macrophages to reverse hypoxia-induced radioresistance. Conclusions: Hepatocytes were the major determinants of the hypoxic microenvironment and radioresponse of CRC cells in our model of metabolic hypoxia. We provide evidence that reoxygenation and radiosensitization of hypoxic CRC cells can be achieved through oxygen sparing induced by endogenous NO production in host hepatocytes.

  1. Hepatocytes Determine the Hypoxic Microenvironment and Radiosensitivity of Colorectal Cancer Cells Through Production of Nitric Oxide That Targets Mitochondrial Respiration

    International Nuclear Information System (INIS)

    Jiang, Heng; Verovski, Valeri N.; Leonard, Wim; Law, Ka Lun; Vermeersch, Marieke; Storme, Guy; Van den Berge, Dirk; Gevaert, Thierry; Sermeus, Alexandra; De Ridder, Mark

    2013-01-01

    Purpose: To determine whether host hepatocytes may reverse hypoxic radioresistance through nitric oxide (NO)-induced oxygen sparing, in a model relevant to colorectal cancer (CRC) liver metastases. Methods and Materials: Hepatocytes and a panel of CRC cells were incubated in a tissue-mimetic coculture system with diffusion-limited oxygenation, and oxygen levels were monitored by an oxygen-sensing fluorescence probe. To activate endogenous NO production, cocultures were exposed to a cytokine mixture, and the expression of inducible nitric oxide synthase was analyzed by reverse transcription–polymerase chain reaction, Western blotting, and NO/nitrite production. The mitochondrial targets of NO were examined by enzymatic activity. To assess hypoxic radioresponse, cocultures were irradiated and reseeded for colonies. Results: Resting hepatocytes consumed 10-40 times more oxygen than mouse CT26 and human DLD-1, HT29, HCT116, and SW480 CRC cells, and thus seemed to be the major effectors of hypoxic conditioning. As a result, hepatocytes caused uniform radioprotection of tumor cells at a 1:1 ratio. Conversely, NO-producing hepatocytes radiosensitized all CRC cell lines more than 1.5-fold, similar to the effect of selective mitochondrial inhibitors. The radiosensitizing effect was associated with a respiratory self-arrest of hepatocytes at the level of aconitase and complex II, which resulted in profound reoxygenation of tumor cells through oxygen sparing. Nitric oxide–producing hepatocytes were at least 10 times more active than NO-producing macrophages to reverse hypoxia-induced radioresistance. Conclusions: Hepatocytes were the major determinants of the hypoxic microenvironment and radioresponse of CRC cells in our model of metabolic hypoxia. We provide evidence that reoxygenation and radiosensitization of hypoxic CRC cells can be achieved through oxygen sparing induced by endogenous NO production in host hepatocytes

  2. Nrf2 impacts cellular bioenergetics by controlling substrate availability for mitochondrial respiration

    Directory of Open Access Journals (Sweden)

    Kira M. Holmström

    2013-06-01

    Transcription factor Nrf2 and its repressor Keap1 regulate a network of cytoprotective genes involving more than 1% of the genome, their best known targets being drug-metabolizing and antioxidant genes. Here we demonstrate a novel role for this pathway in directly regulating mitochondrial bioenergetics in murine neurons and embryonic fibroblasts. Loss of Nrf2 leads to mitochondrial depolarisation, decreased ATP levels and impaired respiration, whereas genetic activation of Nrf2 increases the mitochondrial membrane potential and ATP levels, the rate of respiration and the efficiency of oxidative phosphorylation. We further show that Nrf2-deficient cells have increased production of ATP in glycolysis, which is then used by the F1Fo-ATPase for maintenance of the mitochondrial membrane potential. While the levels and in vitro activities of the respiratory complexes are unaffected by Nrf2 deletion, their activities in isolated mitochondria and intact live cells are substantially impaired. In addition, the rate of regeneration of NADH after inhibition of respiration is much slower in Nrf2-knockout cells than in their wild-type counterparts. Taken together, these results show that Nrf2 directly regulates cellular energy metabolism through modulating the availability of substrates for mitochondrial respiration. Our findings highlight the importance of efficient energy metabolism in Nrf2-mediated cytoprotection.

  3. Far-infrared radiation acutely increases nitric oxide production by increasing Ca(2+) mobilization and Ca(2+)/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179.

    Science.gov (United States)

    Park, Jung-Hyun; Lee, Sangmi; Cho, Du-Hyong; Park, Young Mi; Kang, Duk-Hee; Jo, Inho

    2013-07-12

    Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser(1179)) in a time-dependent manner (up to 40min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca(2+) levels. Treatment with KN-93, a selective inhibitor of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser(1179) phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser(1179) phosphorylation. This study suggests that FIR radiation increases NO production via increasing CaMKII-mediated eNOS-Ser(1179) phosphorylation but TRPV channels may not be involved in this pathway. Our results may provide the molecular mechanism by which FIR radiation improves endothelial function. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Hyperglycemia induced damage to mitochondrial respiration in renal mesangial and tubular cells: Implications for diabetic nephropathy

    Directory of Open Access Journals (Sweden)

    Anna Czajka

    2016-12-01

    Full Text Available Damage to renal tubular and mesangial cells is central to the development of diabetic nephropathy (DN, a complication of diabetes which can lead to renal failure. Mitochondria are the site of cellular respiration and produce energy in the form of ATP via oxidative phosphorylation, and mitochondrial dysfunction has been implicated in DN. Since the kidney is an organ with high bioenergetic needs, we postulated that hyperglycemia causes damage to renal mitochondria resulting in bioenergetic deficit. The bioenergetic profiles and the effect of hyperglycemia on cellular respiration of human primary mesangial (HMCs and proximal tubular cells (HK-2 were compared in normoglycemic and hyperglycemic conditions using the seahorse bio-analyzer. In normoglycemia, HK-2 had significantly lower basal, ATP-linked and maximal respiration rates, and lower reserve capacity compared to HMCs. Hyperglycemia caused a down-regulation of all respiratory parameters within 4 days in HK-2 but not in HMCs. After 8 days of hyperglycemia, down-regulation of respiratory parameters persisted in tubular cells with compensatory up-regulated glycolysis. HMCs had reduced maximal respiration and reserve capacity at 8 days, and by 12 days had compromised mitochondrial respiration despite which they did not enhance glycolysis. These data suggest that diabetes is likely to lead to a cellular deficit in ATP production in both cell types, although with different sensitivities, and this mechanism could significantly contribute to the cellular damage seen in the diabetic kidney. Prevention of diabetes induced damage to renal mitochondrial respiration may be a novel therapeutic approach for the prevention/treatment of DN.

  5. Exposure to high glutamate concentration activates aerobic glycolysis but inhibits ATP-linked respiration in cultured cortical astrocytes.

    Science.gov (United States)

    Shen, Yao; Tian, Yueyang; Shi, Xiaojie; Yang, Jianbo; Ouyang, Li; Gao, Jieqiong; Lu, Jianxin

    2014-08-01

    Astrocytes play a key role in removing the synaptically released glutamate from the extracellular space and maintaining the glutamate below neurotoxic level in the brain. However, high concentration of glutamate leads to toxicity in astrocytes, and the underlying mechanisms are unclear. The purpose of this study was to investigate whether energy metabolism disorder, especially impairment of mitochondrial respiration, is involved in the glutamate-induced gliotoxicity. Exposure to 10-mM glutamate for 48 h stimulated glycolysis and respiration in astrocytes. However, the increased oxygen consumption was used for proton leak and non-mitochondrial respiration, but not for oxidative phosphorylation and ATP generation. When the exposure time extended to 72 h, glycolysis was still activated for ATP generation, but the mitochondrial ATP-linked respiration of astrocytes was reduced. The glutamate-induced astrocyte damage can be mimicked by the non-metabolized substrate d-aspartate but reversed by the non-selective glutamate transporter inhibitor TBOA. In addition, the glutamate toxicity can be partially reversed by vitamin E. These findings demonstrate that changes of bioenergetic profile occur in cultured cortical astrocytes exposed to high concentration of glutamate and highlight the role of mitochondria respiration in glutamate-induced gliotoxicity in cortical astrocytes. Copyright © 2014 John Wiley & Sons, Ltd.

  6. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency

    International Nuclear Information System (INIS)

    Ribeiro, Mariana P.C.; Silva, Filomena S.G.; Santos, Armanda E.; Santos, Maria S.; Custódio, José B.A.

    2013-01-01

    Endoxifen (EDX) is a key active metabolite of tamoxifen (TAM) with higher affinity and specificity to estrogen receptors that also inhibits aromatase activity. It is safe and well tolerated by healthy humans, but its use requires toxicological characterization. In this study, the effects of EDX on mitochondria, the primary targets for xenobiotic-induced toxicity, were monitored to clarify its potential side effects. EDX up to 30 nmol/mg protein did not affect the mitochondrial oxidative phosphorylation. At 50 nmol EDX/mg protein, EDX decreased the ADP phosphorylation rate and a partial collapse of mitochondrial membrane potential (Δψ), that parallels a state 4 stimulation, was observed. As the stimulation of state 4 was not inhibited by oligomycin and 50 nmol EDX/mg protein caused a slight decrease in the light scattering of mitochondria, these data suggest that EDX promotes membrane permeabilization to protons, whereas TAM at the same concentration induced mitochondrial membrane disruption. Moreover, EDX at 10 nmol/mg protein prevented and reversed the Ca 2+ -induced depolarization of ΔΨ and the release of mitochondrial Ca 2+ , similarly to cyclosporine A, indicating that EDX did not affect Ca 2+ uptake, but directly interfered with the proteins of the mitochondrial permeability transition (MPT) megacomplex, inhibiting MPT induction. At this concentration, EDX exhibited antioxidant activity that may account for the protective effect against MPT pore opening. In conclusion, EDX within the range of concentrations reached in tissues did not significantly damage the bioenergetic functions of mitochondria, contrarily to the prodrug TAM, and prevented the MPT pore opening and the oxidative stress in mitochondria, supporting that EDX may be a less toxic drug for women with breast carcinoma. - Highlights: ► Mitochondria are important targets of Endoxifen. ► Endoxifen prevents mitochondrial permeability transition. ► Endoxifen prevents oxidative stress in

  7. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Mariana P.C.; Silva, Filomena S.G.; Santos, Armanda E. [Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra (Portugal); Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra (Portugal); Santos, Maria S. [Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra (Portugal); Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra (Portugal); Custódio, José B.A., E-mail: custodio@ci.uc.pt [Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra (Portugal); Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra (Portugal)

    2013-02-15

    Endoxifen (EDX) is a key active metabolite of tamoxifen (TAM) with higher affinity and specificity to estrogen receptors that also inhibits aromatase activity. It is safe and well tolerated by healthy humans, but its use requires toxicological characterization. In this study, the effects of EDX on mitochondria, the primary targets for xenobiotic-induced toxicity, were monitored to clarify its potential side effects. EDX up to 30 nmol/mg protein did not affect the mitochondrial oxidative phosphorylation. At 50 nmol EDX/mg protein, EDX decreased the ADP phosphorylation rate and a partial collapse of mitochondrial membrane potential (Δψ), that parallels a state 4 stimulation, was observed. As the stimulation of state 4 was not inhibited by oligomycin and 50 nmol EDX/mg protein caused a slight decrease in the light scattering of mitochondria, these data suggest that EDX promotes membrane permeabilization to protons, whereas TAM at the same concentration induced mitochondrial membrane disruption. Moreover, EDX at 10 nmol/mg protein prevented and reversed the Ca{sup 2+}-induced depolarization of ΔΨ and the release of mitochondrial Ca{sup 2+}, similarly to cyclosporine A, indicating that EDX did not affect Ca{sup 2+} uptake, but directly interfered with the proteins of the mitochondrial permeability transition (MPT) megacomplex, inhibiting MPT induction. At this concentration, EDX exhibited antioxidant activity that may account for the protective effect against MPT pore opening. In conclusion, EDX within the range of concentrations reached in tissues did not significantly damage the bioenergetic functions of mitochondria, contrarily to the prodrug TAM, and prevented the MPT pore opening and the oxidative stress in mitochondria, supporting that EDX may be a less toxic drug for women with breast carcinoma. - Highlights: ► Mitochondria are important targets of Endoxifen. ► Endoxifen prevents mitochondrial permeability transition. ► Endoxifen prevents oxidative

  8. Respirator field performance factors

    International Nuclear Information System (INIS)

    Skaggs, B.J.; DeField, J.D.; Strandberg, S.W.; Sutcliffe, C.R.

    1985-01-01

    The Industrial Hygiene Group assisted OSHA and the NRC in measurements of respirator performance under field conditions. They reviewed problems associated with sampling aerosols within the respirator in order to determine fit factors (FFs) or field performance factor (FPF). In addition, they designed an environmental chamber study to determine the effects of temperature and humidity on a respirator wearer

  9. [Endoplasmic-mitochondrial Ca(2+)-functional unit: dependence of respiration of secretory cells on activity of ryanodine- and IP3 - sensitive Ca(2+)-channels].

    Science.gov (United States)

    Velykopols'ka, O Iu; Man'ko, B O; Man'ko, V V

    2012-01-01

    Using Clark oxygen electrode, dependence of mitochondrial functions on Ca(2+)-release channels activity of Chironomus plumosus L. larvae salivary glands suspension was investigated. Cells were ATP-permeabilized in order to enable penetration of exogenous oxidative substrates. Activation of plasmalemmal P2X-receptors (as well as P2Y-receptors) per se does not modify the endogenous respiration of salivary gland suspension. That is, Ca(2+)-influx from extracellular medium does not influence functional activity of mitochondria, although they are located along the basal part of the plasma membrane. Activation of RyRs intensifies endogenous respiration and pyruvate-malate-stimulated respiration, but not succinate-stimulated respiration. Neither activation of IP3Rs (via P2Y-receptors activation), nor their inhibition alters endogenous respiration. Nevertheless, IP3Rs inhibition by 2-APB intensifies succinate-stimulated respiration. All abovementioned facts testify that Ca2+, released from stores via channels, alters functional activity of mitochondria, and undoubtedly confirm the existence of endoplasmic-mitochondrial Ca(2+)-functional unit in Ch. plumosus larvae salivary glands secretory cells. In steady state of endoplasmic-mitochondrial Ca(2+)-functional unit the spontaneous activity of IP3Rs is observed; released through IP3Rs, Ca2+ is accumulated in mitochondria via uniporter and modulates oxidative processes. Activation of RyRs induces the transition of endoplasmic-mitochondrial Ca(2+)-functional unit to the active state, which is required to intensify cell respiration and oxidative phosphorylation. As expected, the transition of endoplasmic-mitochondrial Ca(2+)-functional unit to inactivated state (i. e. inhibition of Ca(2+)-release channels at excessive [Ca2+]i) limits the duration of signal transduction, has protective nature and prevents apoptosis.

  10. The A2b adenosine receptor antagonist PSB-603 promotes oxidative phosphorylation and ROS production in colorectal cancer cells via adenosine receptor-independent mechanism.

    Science.gov (United States)

    Mølck, Christina; Ryall, James; Failla, Laura M; Coates, Janine L; Pascussi, Jean-Marc; Heath, Joan K; Stewart, Gregory; Hollande, Frédéric

    2016-12-01

    Adenosine is a multifaceted regulator of tumor progression. It modulates immune cell activity as well as acting directly on tumor cells. The A 2b adenosine receptor (A 2b -AR) is thought to be an important mediator of these effects. In this study we sought to analyze the contribution of the A 2b -AR to the behavior of colorectal cancer cells. The A 2b -AR antagonist PSB-603 changed cellular redox state without affecting cellular viability. Quantification of cellular bioenergetics demonstrated that PSB-603 increased basal oxygen consumption rates, indicative of enhanced mitochondrial oxidative phosphorylation. Unexpectedly, pharmacological and genetic approaches to antagonize AR-related signalling of PSB-603 did not abolish the response, suggesting that it was AR-independent. PSB-603 also induced acute increases in reactive oxygen species, and PSB-603 synergized with chemotherapy treatment to increase colorectal cancer cell death, consistent with the known link between cellular metabolism and chemotherapy response. PSB-603 alters cellular metabolism in colorectal cancer cells and increases their sensitivity to chemotherapy. Although requiring more mechanistic insight into its A 2b -AR-independent activity, our results show that PSB-603 may have clinical value as an anti-colorectal cancer therapeutic. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. 3-Monochloro-1,2-propanediol (3-MCPD) induces apoptosis via mitochondrial oxidative phosphorylation system impairment and the caspase cascade pathway

    International Nuclear Information System (INIS)

    Peng, Xiaoli; Gan, Jing; Wang, Qian; Shi, Zhenqiang; Xia, Xiaodong

    2016-01-01

    3-Monochloro-1,2-propanediol (3-MCPD) is the most toxic chloropropanols compounds in foodstuff which mainly generated during thermal processing. Kidney is one of the primary target organs for 3-MCPD. Using human embryonic kidney cell (HEK293FT) as an in vitro model, we found that 3-MCPD caused concentration-dependent increase in cytoxicity as assessed by dye uptake, lactatedehydrogenase (LDH) leakage and MTT assays. HEK293FT cell treated with 3-MCPD suffered the decrease of mitochondrial membrane potential and the impairment of mitochondrial oxidative phosphorylation system, especially the reduced amount of mRNA expression and protein synthesis of electron transport chain complex II, complex IV, and complex III. More importantly, energy release (ATP synthesis) was significantly inhibited by 3-MCPD resulting from the down regulation expressions of ATP synthase (ATP6 and ATP8), as well as the loss of transmembrane potential required for synthesis of ATP. The decreased ratio of mitochondrial apoptogenic factors Bax/Bcl-2 and the cytochrome-c release from mitochondria to cytosol followed by the activation of apoptotic initiators caspase 9 and apoptotic executioners (caspase 3, caspase 6 and caspase 7) leading to apoptosis. The activation of caspase 8 and caspase 2 implied that there were probably other factors to induce the caspase-dependent apoptosis.

  12. 3-Monochloro-1,2-propanediol (3-MCPD) induces apoptosis via mitochondrial oxidative phosphorylation system impairment and the caspase cascade pathway.

    Science.gov (United States)

    Peng, Xiaoli; Gan, Jing; Wang, Qian; Shi, Zhenqiang; Xia, Xiaodong

    2016-11-30

    3-Monochloro-1,2-propanediol (3-MCPD) is the most toxic chloropropanols compounds in foodstuff which mainly generated during thermal processing. Kidney is one of the primary target organs for 3-MCPD. Using human embryonic kidney cell (HEK293FT) as an in vitro model, we found that 3-MCPD caused concentration-dependent increase in cytoxicity as assessed by dye uptake, lactatedehydrogenase (LDH) leakage and MTT assays. HEK293FT cell treated with 3-MCPD suffered the decrease of mitochondrial membrane potential and the impairment of mitochondrial oxidative phosphorylation system, especially the reduced amount of mRNA expression and protein synthesis of electron transport chain complex II, complex IV, and complex III. More importantly, energy release (ATP synthesis) was significantly inhibited by 3-MCPD resulting from the down regulation expressions of ATP synthase (ATP6 and ATP8), as well as the loss of transmembrane potential required for synthesis of ATP. The decreased ratio of mitochondrial apoptogenic factors Bax/Bcl-2 and the cytochrome-c release from mitochondria to cytosol followed by the activation of apoptotic initiators caspase 9 and apoptotic executioners (caspase 3, caspase 6 and caspase 7) leading to apoptosis. The activation of caspase 8 and caspase 2 implied that there were probably other factors to induce the caspase-dependent apoptosis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Increased heme synthesis in yeast induces a metabolic switch from fermentation to respiration even under conditions of glucose repression.

    Science.gov (United States)

    Zhang, Tiantian; Bu, Pengli; Zeng, Joey; Vancura, Ales

    2017-10-13

    Regulation of mitochondrial biogenesis and respiration is a complex process that involves several signaling pathways and transcription factors as well as communication between the nuclear and mitochondrial genomes. Under aerobic conditions, the budding yeast Saccharomyces cerevisiae metabolizes glucose predominantly by glycolysis and fermentation. We have recently shown that altered chromatin structure in yeast induces respiration by a mechanism that requires transport and metabolism of pyruvate in mitochondria. However, how pyruvate controls the transcriptional responses underlying the metabolic switch from fermentation to respiration is unknown. Here, we report that this pyruvate effect involves heme. We found that heme induces transcription of HAP4 , the transcriptional activation subunit of the Hap2/3/4/5p complex, required for growth on nonfermentable carbon sources, in a Hap1p- and Hap2/3/4/5p-dependent manner. Increasing cellular heme levels by inactivating ROX1 , which encodes a repressor of many hypoxic genes, or by overexpressing HEM3 or HEM12 induced respiration and elevated ATP levels. Increased heme synthesis, even under conditions of glucose repression, activated Hap1p and the Hap2/3/4/5p complex and induced transcription of HAP4 and genes required for the tricarboxylic acid (TCA) cycle, electron transport chain, and oxidative phosphorylation, leading to a switch from fermentation to respiration. Conversely, inhibiting metabolic flux into the TCA cycle reduced cellular heme levels and HAP4 transcription. Together, our results indicate that the glucose-mediated repression of respiration in budding yeast is at least partly due to the low cellular heme level. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Choosing the right respirator

    International Nuclear Information System (INIS)

    Bidwell, J.

    1997-01-01

    Selecting respirators to help protect workers from airborne contaminants can be a confusing process. The consequences of selecting the incorrect respirator can be intimidating, and worker safety and health may be dramatically and irreparably affected if an inappropriate respirator is chosen. When used in the workplace, a formal respiratory protection program must be established covering the basic requirements outlined in the OSHA Respiratory Protection Standard (29 CFR 1910.134). Education and training must be properly emphasized and conducted periodically. Maintenance, cleaning, and storage programs must be established and routinely followed for reusable respirators. The process of establishing a respiratory protection program can be broken down into four basic steps: Identify respiratory hazards and concentrations; understand the contaminants effects on workers' health; select appropriate respiratory protection; and train in proper respirator use and maintenance. These four steps are the foundation for establishing a basic respirator protection program. Be sure to consult state and federal OSHA requirements to ensure that the program complies. Leading industrial respirator manufacturers should be able to assist with on-site training and education in this four-step process, in addition to helping employers train their workers and conduct respirator fit testing

  15. 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+.

  16. Effects of ionization and nitrous oxide on grated carrot respiration; Effets de l`ionisation et du protoxyde d`azote sur la respiration de carottes rapees. Amelioration de la conservation de produits de 4eme gamme

    Energy Technology Data Exchange (ETDEWEB)

    Chervin, C.

    1992-06-01

    Two treatments (nitrous oxide and irradiation) have been applied on grated carrots to reduce the respiratory crisis induced by wounding. Nitrous oxide inhibited cytochrome c oxidase; but, it neither diminished O{sub 2} consumption of the tissues, nor modified atmospheres in a favourable way for conservation of grated carrots, stored in plastic bags (in the conditions chosen for this study). On the contrary, irradiation inhibited simultaneously the respiratory crisis and the ethylene production, both induced by wounding. This behaviour led to a lower consumption of sugars in irradiated tissues and to the generation of atmospheres, which were better adapted to the conservation needs (it was necessary to use plastic film with high permeability). Finally, an applied study demonstrated that irradiation, by permitting a less denaturing preparation than industrial process, allowed the conservation of produces with a better quality (nutritional, sensory and microbiological). Biochemical analyses have been validated by sensory analyses.

  17. Direct Effects of (−-Epicatechin and Procyanidin B2 on the Respiration of Rat Heart Mitochondria

    Directory of Open Access Journals (Sweden)

    Dalia M. Kopustinskiene

    2015-01-01

    Full Text Available Flavonol (−-epicatechin and its derived dimer procyanidin B2, present in high amounts in cocoa products, have been shown to exert beneficial effects on the heart and cardiovascular system; however, their mechanism of action has not been fully elucidated. We studied effects of (−-epicatechin and procyanidin B2 on the oxidative phosphorylation of isolated rat heart mitochondria. (−-Epicatechin and procyanidin B2 had stimulating effect (up to 30% compared to control on substrate-driven (State 2 mitochondrial respiration. Their effect was dependent on the respiratory substrates used. (−-Epicatechin at higher concentrations (from 0.27 µg/mL significantly decreased (up to 15% substrate- and ADP-driven (State 3 mitochondrial respiration in case of pyruvate and malate oxidation only. Procyanidin B2 (0.7–17.9 ng/mL inhibited State 3 respiration rate up to 19%, the most profound effect being expressed with succinate as the substrate. (−-Epicatechin at concentrations of 0.23 µg/mL and 0.46 µg/mL prevented loss of the cytochrome c from mitochondria when substrate was succinate, supporting the evidence of membrane stabilizing properties of this flavonol. Thus, both (−-epicatechin and procyanidin B2 directly influenced mitochondrial functions and the observed effects could help to explain cardiometabolic risk reduction ascribed to the consumption of modest amounts of cocoa products.

  18. Transcription, Signaling Receptor Activity, Oxidative Phosphorylation, and Fatty Acid Metabolism Mediate the Presence of Closely Related Species in Distinct Intertidal and Cold-Seep Habitats.

    Science.gov (United States)

    Van Campenhout, Jelle; Vanreusel, Ann; Van Belleghem, Steven; Derycke, Sofie

    2015-12-03

    Bathyal cold seeps are isolated extreme deep-sea environments characterized by low species diversity while biomass can be high. The Håkon Mosby mud volcano (Barents Sea, 1,280 m) is a rather stable chemosynthetic driven habitat characterized by prominent surface bacterial mats with high sulfide concentrations and low oxygen levels. Here, the nematode Halomonhystera hermesi thrives in high abundances (11,000 individuals 10 cm(-2)). Halomonhystera hermesi is a member of the intertidal Halomonhystera disjuncta species complex that includes five cryptic species (GD1-5). GD1-5's common habitat is characterized by strong environmental fluctuations. Here, we compared the transcriptomes of H. hermesi and GD1, H. hermesi's closest relative. Genes encoding proteins involved in oxidative phosphorylation are more strongly expressed in H. hermesi than in GD1, and many genes were only observed in H. hermesi while being completely absent in GD1. Both observations could in part be attributed to high sulfide concentrations and low oxygen levels. Additionally, fatty acid elongation was also prominent in H. hermesi confirming the importance of highly unsaturated fatty acids in this species. Significant higher amounts of transcription factors and genes involved in signaling receptor activity were observed in GD1 (many of which were completely absent in H. hermesi), allowing fast signaling and transcriptional reprogramming which can mediate survival in dynamic intertidal environments. GC content was approximately 8% higher in H. hermesi coding unigenes resulting in differential codon usage between both species and a higher proportion of amino acids with GC-rich codons in H. hermesi. In general our results showed that most pathways were active in both environments and that only three genes are under natural selection. This indicates that also plasticity should be taken in consideration in the evolutionary history of Halomonhystera species. Such plasticity, as well as possible

  19. Respiration in Aquatic Insects.

    Science.gov (United States)

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  20. Sustained oxidative stress causes late acute renal failure via duplex regulation on p38 MAPK and Akt phosphorylation in severely burned rats.

    Directory of Open Access Journals (Sweden)

    Yafei Feng

    Full Text Available BACKGROUND: Clinical evidence indicates that late acute renal failure (ARF predicts high mortality in severely burned patients but the pathophysiology of late ARF remains undefined. This study was designed to test the hypothesis that sustained reactive oxygen species (ROS induced late ARF in a severely burned rat model and to investigate the signaling mechanisms involved. MATERIALS AND METHODS: Rats were exposed to 100°C bath for 15 s to induce severe burn injury (40% of total body surface area. Renal function, ROS generation, tubular necrosis and apoptosis, and phosphorylation of MAPK and Akt were measured during 72 hours after burn. RESULTS: Renal function as assessed by serum creatinine and blood urea nitrogen deteriorated significantly at 3 h after burn, alleviated at 6 h but worsened at 48 h and 72 h, indicating a late ARF was induced. Apoptotic cells and cleavage caspase-3 in the kidney went up slowly and turned into significant at 48 h and 72 h. Tubular cell ROS production shot up at 6 h and continuously rose during the 72-h experiment. Scavenging ROS with tempol markedly attenuated tubular apoptosis and renal dysfunction at 72 h after burn. Interestingly, renal p38 MAPK phosphorylation elevated in a time dependent manner whereas Akt phosphorylation increased during the first 24 h but decreased at 48 h after burn. The p38 MAPK specific inhibitor SB203580 alleviated whereas Akt inhibitor exacerbated burn-induced tubular apoptosis and renal dysfunction. Furthermore, tempol treatment exerted a duplex regulation through inhibiting p38 MAPK phosphorylation but further increasing Akt phosphorylation at 72 h postburn. CONCLUSIONS: These results demonstrate that sustained renal ROS overproduction induces continuous tubular cell apoptosis and thus a late ARF at 72 h after burn in severely burned rats, which may result from ROS-mediated activation of p38 MAPK but a late inhibition of Akt phosphorylation.

  1. Impaired activity of CCA-adding enzyme TRNT1 impacts OXPHOS complexes and cellular respiration in SIFD patient-derived fibroblasts.

    Science.gov (United States)

    Liwak-Muir, Urszula; Mamady, Hapsatou; Naas, Turaya; Wylie, Quinlan; McBride, Skye; Lines, Matthew; Michaud, Jean; Baird, Stephen D; Chakraborty, Pranesh K; Holcik, Martin

    2016-06-18

    SIFD (Sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay) is a novel form of congenital sideroblastic anemia associated with B-cell immunodeficiency, periodic fevers, and developmental delay caused by mutations in the CCA-adding enzyme TRNT1, but the precise molecular pathophysiology is not known. We show that the disease causing mutations in patient-derived fibroblasts do not affect subcellular localization of TRNT1 and show no gross morphological differences when compared to control cells. Analysis of cellular respiration and oxidative phosphorylation (OXPHOS) complexes demonstrates that both basal and maximal respiration rates are decreased in patient cells, which may be attributed to an observed decrease in the abundance of select proteins of the OXPHOS complexes. Our data provides further insight into cellular pathophysiology of SIFD.

  2. [ATP-synthetase activity, respiration and cytochromes of rat heart mitochondria in aging and hyperthyroidism].

    Science.gov (United States)

    Lemeshko, V V; Kaliman, P A; Belostotskaia, L I; Uchitel', A A

    1982-04-01

    The ATP-synthetase activity, the rate of oxygen uptake under different metabolic conditions, the tightness of coupling of respiration to oxidative phosphorylation and the cytochrome contents in heart mitochondria of rats from different age groups were studied under normal conditions and in hyperthyroidism. It was found that heart mitochondria of aged animals did not practically differ in terms of their functional activity from those of the young animals. Administration of thyroxin to the animals from all age groups produced no significant effects on the state of mitochondria, increasing the rate of ATP synthesis on alpha-glycerophosphate, which was especially well-pronounced in aged animals, and the cytochrome content in 1-month-old rats.

  3. Glycolysis-respiration relationships in a neuroblastoma cell line.

    Science.gov (United States)

    Swerdlow, Russell H; E, Lezi; Aires, Daniel; Lu, Jianghua

    2013-04-01

    Although some reciprocal glycolysis-respiration relationships are well recognized, the relationship between reduced glycolysis flux and mitochondrial respiration has not been critically characterized. We concomitantly measured the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of SH-SY5Y neuroblastoma cells under free and restricted glycolysis flux conditions. Under conditions of fixed energy demand ECAR and OCR values showed a reciprocal relationship. In addition to observing an expected Crabtree effect in which increasing glucose availability raised the ECAR and reduced the OCR, a novel reciprocal relationship was documented in which reducing the ECAR via glucose deprivation or glycolysis inhibition increased the OCR. Substituting galactose for glucose, which reduces net glycolysis ATP yield without blocking glycolysis flux, similarly reduced the ECAR and increased the OCR. We further determined how reduced ECAR conditions affect proteins that associate with energy sensing and energy response pathways. ERK phosphorylation, SIRT1, and HIF1a decreased while AKT, p38, and AMPK phosphorylation increased. These data document a novel intracellular glycolysis-respiration effect in which restricting glycolysis flux increases mitochondrial respiration. Since this effect can be used to manipulate cell bioenergetic infrastructures, this particular glycolysis-respiration effect can practically inform the development of new mitochondrial medicine approaches. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Increased oxidative stress and anaerobic energy release, but blunted Thr172-AMPKα phosphorylation, in response to sprint exercise in severe acute hypoxia in humans.

    Science.gov (United States)

    Morales-Alamo, David; Ponce-González, Jesús Gustavo; Guadalupe-Grau, Amelia; Rodríguez-García, Lorena; Santana, Alfredo; Cusso, Maria Roser; Guerrero, Mario; Guerra, Borja; Dorado, Cecilia; Calbet, José A L

    2012-09-01

    AMP-activated protein kinase (AMPK) is a major mediator of the exercise response and a molecular target to improve insulin sensitivity. To determine if the anaerobic component of the exercise response, which is exaggerated when sprint is performed in severe acute hypoxia, influences sprint exercise-elicited Thr(172)-AMPKα phosphorylation, 10 volunteers performed a single 30-s sprint (Wingate test) in normoxia and in severe acute hypoxia (inspired Po(2): 75 mmHg). Vastus lateralis muscle biopsies were obtained before and immediately after 30 and 120 min postsprint. Mean power output and O(2) consumption were 6% and 37%, respectively, lower in hypoxia than in normoxia. O(2) deficit and muscle lactate accumulation were greater in hypoxia than in normoxia. Carbonylated skeletal muscle and plasma proteins were increased after the sprint in hypoxia. Thr(172)-AMPKα phosphorylation was increased by 3.1-fold 30 min after the sprint in normoxia. This effect was prevented by hypoxia. The NAD(+)-to-NADH.H(+) ratio was reduced (by 24-fold) after the sprints, with a greater reduction in hypoxia than in normoxia (P exercise in human skeletal muscle is altered in severe acute hypoxia, which abrogated Thr(172)-AMPKα phosphorylation, likely due to lower LKB1 activation by SIRT1.

  5. Mitochondrial complex III defects contribute to inefficient respiration and ATP synthesis in the myocardium of Trypanosoma cruzi-infected mice.

    Science.gov (United States)

    Wen, Jian-Jun; Garg, Nisha Jain

    2010-01-01

    In this study, we conducted a thorough analysis of mitochondrial bioenergetic function as well as the biochemical and molecular factors that are deregulated and contribute to compromised adenosine triphosphate (ATP) production in the myocardium during Trypanosoma cruzi infection. We show that ADP-stimulated state 3 respiration and ATP synthesis supported by pyruvate/malate (provides electrons to complex I) and succinate (provides electrons to complex II) substrates were significantly decreased in left ventricular tissue and isolated cardiac mitochondria of infected mice. The decreased mitochondrial ATP synthesis in infected murine hearts was not a result of uncoupling between the electron-transport chain and oxidative phosphorylation and decreased availability of the intermediary metabolites (e.g., NADH). The observed decline in the activities of complex-I, -IV, and -V was not physiologically relevant and did not contribute to compromised respiration and ATP synthesis in infected myocardium. Instead, complex III activity was decreased above the threshold level and contributed to respiratory-chain inefficiency and the resulting decline in mitochondrial ATP synthesis in infected myocardium. The loss in complex III activity occurred as a consequence of cytochrome b depletion. Treatment of infected mice with phenyl-alpha-tert-butyl nitrone (PBN, antioxidant) was beneficial in preserving the mtDNA-encoded cytochrome b expression, and subsequently resulted in improved complex III activity, mitochondrial respiration, and ATP production in infected myocardium. Overall, we provide novel data on the mechanism(s) involved in cardiac bioenergetic inefficiency during T. cruzi infection.

  6. Cattle respiration facility

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Lund, Peter; Weisbjerg, Martin Riis

    2012-01-01

    In Denmark, the emission rate of methane from dairy cows has been calculated using the IPCC standard values for dairy cows in Western countries, due to the lack of national data. Therefore, four respiration chambers for dairy cows were built with the main purpose of measuring methane, but also...

  7. Induction of mitochondrial biogenesis and respiration is associated with mTOR regulation in hepatocytes of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA)

    Energy Technology Data Exchange (ETDEWEB)

    Hagland, Hanne R.; Nilsson, Linn I.H. [Department of Biomedicine, University of Bergen (Norway); Burri, Lena [Institute of Medicine, University of Bergen, Haukeland University Hospital (Norway); Nikolaisen, Julie [Department of Biomedicine, University of Bergen (Norway); Berge, Rolf K. [Institute of Medicine, University of Bergen, Haukeland University Hospital (Norway); Department of Heart Disease, Haukeland University Hospital (Norway); Tronstad, Karl J., E-mail: karl.tronstad@biomed.uib.no [Department of Biomedicine, University of Bergen (Norway)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer We investigated mechanisms of mitochondrial regulation in rat hepatocytes. Black-Right-Pointing-Pointer Tetradecylthioacetic acid (TTA) was employed to activate mitochondrial oxidation. Black-Right-Pointing-Pointer Mitochondrial biogenesis and respiration were induced. Black-Right-Pointing-Pointer It was confirmed that PPAR target genes were induced. Black-Right-Pointing-Pointer The mechanism involved activation mTOR. -- Abstract: The hypolipidemic effect of peroxisome proliferator-activated receptor (PPAR) activators has been explained by increasing mitochondrial fatty acid oxidation, as observed in livers of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA). PPAR-activation does, however, not fully explain the metabolic adaptations observed in hepatocytes after treatment with TTA. We therefore characterized the mitochondrial effects, and linked this to signalling by the metabolic sensor, the mammalian target of rapamycin (mTOR). In hepatocytes isolated from TTA-treated rats, the changes in cellular content and morphology were consistent with hypertrophy. This was associated with induction of multiple mitochondrial biomarkers, including mitochondrial DNA, citrate synthase and mRNAs of mitochondrial proteins. Transcription analysis further confirmed activation of PPAR{alpha}-associated genes, in addition to genes related to mitochondrial biogenesis and function. Analysis of mitochondrial respiration revealed that the capacity of both electron transport and oxidative phosphorylation were increased. These effects coincided with activation of the stress related factor, ERK1/2, and mTOR. The protein level and phosphorylation of the downstream mTOR actors eIF4G and 4E-BP1 were induced. In summary, TTA increases mitochondrial respiration by inducing hypertrophy and mitochondrial biogenesis in rat hepatocytes, via adaptive regulation of PPARs as well as mTOR.

  8. Heat production of pig platelets in relation with glycolysis and respiration.

    Science.gov (United States)

    Nanri, H; Minakami, S

    1983-01-01

    Heat production of pig platelets was measured on a flow microcalorimeter with simultaneous measurements of the oxygen consumption and metabolite change of the suspension. The heat production associated with the glycolytic reaction was estimated from the decrease in the heat production caused by the addition of sodium fluoride. The glycolytic heat production was about -75 kJ per mol of lactate formed, which is the sum of the enthalpy values for the conversion of glucose to lactic acid and that for the neutralization of the acid. The heat production due to the respiration was estimated from the heat production of the cells at various pH. The respiratory heat production was about -475 kJ per mol oxygen consumed, which agrees with the enthalpy change for the non-phosphorylating respiration of mitochondria or for the complete oxidation of glucose or fatty acids. The heat production of the cells increased by the alkalinization of the medium, and the increase of the heat production was parallel with the increase in the lactate formation.

  9. Respirators. Does your face fit

    Energy Technology Data Exchange (ETDEWEB)

    Caro, N M; Else, D

    1981-04-01

    The authors carried out a survey of face sizes of men and women of four different ethnic origins and carried out face-seal leakage trials on four corresponding test panels. No single respirator design is likely to fit all members of the workforce, and it may be necessary to stock respirators from more than one manufacturers.Three or four different respirators or size of respirator may be needed. However, the use of lossely-fitting respirators such as Airsteam helmets could remove the necessity for exhaustive fitting procedures.

  10. Hepatocyte-protective effect of nectandrin B, a nutmeg lignan, against oxidative stress: Role of Nrf2 activation through ERK phosphorylation and AMPK-dependent inhibition of GSK-3β

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jae-Sook; Kim, Eun-Kyung; Choi, Yong-Won [Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do 15588 (Korea, Republic of); Oh, Won Keun [College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University (Korea, Republic of); Kim, Young-Mi, E-mail: ymikim12@hanyang.ac.kr [Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do 15588 (Korea, Republic of)

    2016-09-15

    Oxidative stress can contribute to the development and progression of liver diseases, such as drug-induced or alcoholic liver injury, nonalcoholic fatty liver disease, and nonalcoholic steatohepatitis. Nectandrin B is a bioactive lignan isolated from nutmeg extract. To date, little information is available about its pharmacological activities in the liver. This study investigated the hepatocyte-protective effect of nectandrin B against tert-butylhydroperoxide-induced oxidative injury and the underlying molecular mechanism. The cell viability assay revealed that nectandrin B prevents apoptosis stimulated by tert-butylhydroperoxide in both HepG2 cells and primary mouse hepatocytes. Nectandrin B also attenuated ROS production and restored the depleted glutathione level. Real-time PCR and immunoblot analyses showed that the expression of glutamate-cysteine ligase, an enzyme responsible for the glutathione biosynthesis, was induced by nectandrin B, indicating its indirect antioxidative effect. The NF-E2-related factor-2 (Nrf2) regulates gene expression of an array of antioxidant enzymes in hepatocytes. Nectandrin B stimulated Nrf2 activation as evidenced by its enhanced nuclear accumulation and increased antioxidant response element (ARE)-luciferase activity. Intriguingly, the hepatocyte-protective effect of nectandrin B against oxidative damage was completely abrogated by Nrf2 knockdown using Nrf2 specific siRNA. Nectandrin B promoted ERK activation, but inactivated GSK-3β through the AMPK-mediated inhibitory phosphorylation. The enforced overexpression of dominant-negative mutant of MEK1 or AMPKα, or wild-type GSK-3β inhibited the increase in the NQO1-ARE-luciferase activity stimulated by nectandrin B, suggesting that both ERK and AMPK-GSK-3β signalings are involved in the activation of Nrf2/ARE pathway by nectandrin B. Consistent with this, cytoprotection and restoration of glutathione level by nectandrin B was also blocked by the overexpression of dominant

  11. Neuroprotective effects of Arctium lappa L. roots against glutamate-induced oxidative stress by inhibiting phosphorylation of p38, JNK and ERK 1/2 MAPKs in PC12 cells.

    Science.gov (United States)

    Tian, Xing; Sui, Shuang; Huang, Jin; Bai, Jun-Peng; Ren, Tian-Shu; Zhao, Qing-Chun

    2014-07-01

    Many studies have shown that glutamate-induced oxidative stress can lead to neuronal cell death involved in the development of neurodegenerative diseases. In this work, protective effects of ethyl acetate extract (EAE) of Arctium lappa L. roots against glutamate-induced oxidative stress in PC12 cells were evaluated. Also, the effects of EAE on antioxidant system, mitochondrial pathway, and signal transduction pathway were explored. Pretreatment with EAE significantly increased cell viability, activities of GSH-Px and SOD, mitochondrial membrane potential and reduced LDH leakage, ROS formation, and nuclear condensation in a dose-dependent manner. Furthermore, western blot results revealed that EAE increased the Bcl-2/Bax ratio, and inhibited the up-regulation of caspase-3, release of cytochrome c, phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase 1/2 (ERK 1/2). Therefore, our results indicate that EAE may be a promising neuroprotective agent for the prevention and treatment of neurodegenerative diseases implicated with oxidative stress. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Effect of Dinitrophenol on the Heats of Respiration of Germinating Seeds of Prosopis juliflora, Kochia scoparia, and Oxyria digyna

    Science.gov (United States)

    Lacher, John R.; Amador, Albert; Snow, K.

    1966-01-01

    During a 36-hour period, the rate of absorption of oxygen, respiration quotient, and rate of evolution of heat have been measured using seeds of Prosopis juliflora, Kochia scoparia, and Oxyria digyna. The results obtained in pure water were compared with those obtained in dilute solutions of dinitrolphenol. The data appear to be reproducible to ± 10% at the end of the 36-hour period and are independent of the amount of seeds used, provided it was 0.05 g or less. For a given amount of oxygen absorbed, more heat was liberated when the seeds were in a dinitrophenol solution. The results permit an estimate to be made of the heat energy stored in oxidative phosphorylation. PMID:16656420

  13. Respirable dust and respirable silica exposure in Ontario gold mines.

    Science.gov (United States)

    Verma, Dave K; Rajhans, Gyan S; Malik, Om P; des Tombe, Karen

    2014-01-01

    A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978-1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7-8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978-1979, the industry wide mean respirable dust was about 1 mg/m(3), and the mean respirable silica was 0.08 mg/m(3.)The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers' compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

  14. Cytosolic phospholipase A2 alpha amplifies early cyclooxygenase-2 expression, oxidative stress and MAP kinase phosphorylation after cerebral ischemia in mice

    Directory of Open Access Journals (Sweden)

    Koehler Raymond C

    2010-07-01

    Full Text Available Abstract Background The enzyme cytosolic phospholipase A2 alpha (cPLA2α has been implicated in the progression of cerebral injury following ischemia and reperfusion. Previous studies in rodents suggest that cPLA2α enhances delayed injury extension and disruption of the blood brain barrier many hours after reperfusion. In this study we investigated the role of cPLA2α in early ischemic cerebral injury. Methods Middle cerebral artery occlusion (MCAO was performed on cPLA2α+/+ and cPLA2α-/- mice for 2 hours followed by 0, 2, or 6 hours of reperfusion. The levels of cPLA2α, cyclooxygenase-2, neuronal morphology and reactive oxygen species in the ischemic and contralateral hemispheres were evaluated by light and fluorescent microscopy. PGE2 content was compared between genotypes and hemispheres after MCAO and MCAO and 6 hours reperfusion. Regional cerebral blood flow was measured during MCAO and phosphorylation of relevant MAPKs in brain protein homogenates was measured by Western analysis after 6 hours of reperfusion. Results Neuronal cPLA2α protein increased by 2-fold immediately after MCAO and returned to pre-MCAO levels after 2 hours reperfusion. Neuronal cyclooxygenase-2 induction and PGE2 concentration were greater in cPLA2α+/+ compared to cPLA2α-/- ischemic cortex. Neuronal swelling in ischemic regions was significantly greater in the cPLA2α+/+ than in cPLA2α-/- brains (+/+: 2.2 ± 0.3 fold vs. -/-: 1.7 ± 0.4 fold increase; P 2α+/+ ischemic core than in cPLA2α-/- (+/+: 7.12 ± 1.2 fold vs. -/-: 3.1 ± 1.4 fold; P 2α+/+, but not cPLA2α-/-, had disruption of neuron morphology and decreased PGE2 content. Phosphorylation of the MAPKs-p38, ERK 1/2, and MEK 1/2-was significantly greater in cPLA2a+/+ than in cPLA2α-/- ischemic cortex 6 hours after reperfusion. Conclusions These results indicate that cPLA2α modulates the earliest molecular and injury responses after cerebral ischemia and have implications for the potential clinical

  15. Activated Macrophages as a Novel Determinant of Tumor Cell Radioresponse: The Role of Nitric Oxide-Mediated Inhibition of Cellular Respiration and Oxygen Sparing

    International Nuclear Information System (INIS)

    Jiang Heng; De Ridder, Mark; Verovski, Valeri N.; Sonveaux, Pierre; Jordan, Benedicte F.; Law, Kalun; Monsaert, Christinne; Van den Berge, Dirk L.; Verellen, Dirk; Feron, Olivier; Gallez, Bernard; Storme, Guy A.

    2010-01-01

    Purpose: Nitric oxide (NO), synthesized by the inducible nitric oxide synthase (iNOS), is known to inhibit metabolic oxygen consumption because of interference with mitochondrial respiratory activity. This study examined whether activation of iNOS (a) directly in tumor cells or (b) in bystander macrophages may improve radioresponse through sparing of oxygen. Methods and Materials: EMT-6 tumor cells and RAW 264.7 macrophages were exposed to bacterial lipopolysaccharide plus interferon-γ, and examined for iNOS expression by reverse transcription polymerase chain reaction, Western blotting and enzymatic activity. Tumor cells alone, or combined with macrophages were subjected to metabolic hypoxia and analyzed for radiosensitivity by clonogenic assay, and for oxygen consumption by electron paramagnetic resonance and a Clark-type electrode. Results: Both tumor cells and macrophages displayed a coherent picture of iNOS induction at transcriptional/translational levels and NO/nitrite production, whereas macrophages showed also co-induction of the inducible heme oxygenase-1, which is associated with carbon monoxide (CO) and bilirubin production. Activation of iNOS in tumor cells resulted in a profound oxygen sparing and a 2.3-fold radiosensitization. Bystander NO-producing, but not CO-producing, macrophages were able to block oxygen consumption by 1.9-fold and to radiosensitize tumor cells by 2.2-fold. Both effects could be neutralized by aminoguanidine, a metabolic iNOS inhibitor. An improved radioresponse was clearly observed at macrophages to tumor cells ratios ranging between 1:16 to 1:1. Conclusions: Our study is the first, as far as we are aware, to provide evidence that iNOS may induce radiosensitization through oxygen sparing, and illuminates NO-producing macrophages as a novel determinant of tumor cell radioresponse within the hypoxic tumor microenvironment.

  16. Mitochondrial oxidative function and type 2 diabetes

    DEFF Research Database (Denmark)

    Rabøl, Rasmus; Boushel, Robert; Dela, Flemming

    2006-01-01

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

  17. Sevoflurane-induced Preconditioning Impact of Protocol and Aprotinin Administration on Infarct Size and Endothelial Nitric-Oxide Synthase Phosphorylation in the Rat Heart In Vivo

    NARCIS (Netherlands)

    Fräßdorf, Jan; Huhn, Ragnar; Weber, Nina C.; Ebel, Dirk; Wingert, Nadja; Preckel, Benedikt; Toma, Octavian; Schlack, Wolfgang; Hollmann, Markus W.

    2010-01-01

    Background Sevoflurane induces preconditioning (SevoPC) 1 he effect of aprotinin and the involvement of endothelial nitric-oxide synthase (NOS) on SevoPC are unknown We investigated (1) whether SevoPC is strengthened by multiple preconditioning cycles (2) whether SevoPC is blocked by aprotinin, and

  18. [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.

  19. Altered expression of genes involved in mitochondrial oxidative phosphorylation and insulin signaling in skeletal muscle of obese women with polycystic ovary syndrome (PCOS)

    DEFF Research Database (Denmark)

    Skov, Vibe

    be of similar importance for insulin resistance in the polycystic ovary syndrome (PCOS).   Materials and methods: Using the HG-U133 Plus 2.0 expression array from Affymetrix, we analyzed gene expression in skeletal muscle from obese women with PCOS (n=16) and age- and body mass index-matched control women (n=13...... a sum statistic and conducting a permutation test. Subsequently, we performed biological pathway analysis using Gene Set Enrichment Analysis (GSEA) and Gene Microarray Pathway Profiler (GenMAPP).   Results: Women with PCOS were characterized by fasting hyperinsulinemia and impaired insulin...... validated by quantitative real-time PCR and immunoblot analyses.   Conclusion: Our results, for the first time, provide evidence for an association between insulin resistance and impaired mitochondrial oxidative metabolism in skeletal muscle in women with PCOS. Furthermore, differential expression of genes...

  20. Mitochondrial respiration scavenges extramitochondrial superoxide anion via a nonenzymatic mechanism.

    OpenAIRE

    Guidot, D M; Repine, J E; Kitlowski, A D; Flores, S C; Nelson, S K; Wright, R M; McCord, J M

    1995-01-01

    We determined that mitochondrial respiration reduced cytosolic oxidant stress in vivo and scavenged extramitochondrial superoxide anion (O2-.) in vitro. First, Saccharomyces cerevisiae deficient in both the cytosolic antioxidant cupro-zinc superoxide dismutase (Cu,Zn-SOD) and electron transport (Rho0 state) grew poorly (P 0.05) in all yeast. Seco...

  1. Flux control analysis of mitochondrial oxidative phosphorylation in rat skeletal muscle: pyruvate and palmitoyl-carnitine as substrates give different control patterns

    DEFF Research Database (Denmark)

    Fritzen, Anette J; Grunnet, Niels; Quistorff, Bjørn

    2007-01-01

    was associated with the ADP-generating system, i.e., 0.58 +/- 0.05 with pyruvate, but significantly lower, 0.40 +/- 0.05, with palmitoyl-carnitine as substrate. The flux control coefficients of complex I, III and IV, the ATP synthase, the ATP/ADP carrier and the P(i) carrier were 0.070 +/- 0.03, 0.083 +/- 0.......04, 0.054 +/- 0.01, 0.11 +/- 0.03, 0.090 +/- 0.03 and 0.026 +/- 0.01, respectively, with pyruvate as substrate. With palmitoyl-carnitine all control coefficients were significantly different, except for the P(i) carrier (i.e., 0.024 +/- 0.001, 0.036 +/- 0.01, 0.052 +/- 0.02, 0.020 +/- 0.002, 0.034 +/- 0.......02 and 0.012 +/- 0.002, respectively), probably caused by the shift from NADH to FADH(2) oxidation. The sum of flux control coefficients was not significantly different from unity with pyruvate, while only 0.58 with palmitoyl-carnitine, indicating significant control contributions from the enzymes involved...

  2. Respiration in spiders (Araneae).

    Science.gov (United States)

    Schmitz, Anke

    2016-05-01

    Spiders (Araneae) are unique regarding their respiratory system: they are the only animal group that breathe simultaneously with lungs and tracheae. Looking at the physiology of respiration the existence of tracheae plays an important role in spiders with a well-developed tracheal system. Other factors as sex, life time, type of prey capture and the high ability to gain energy anaerobically influence the resting and the active metabolic rate intensely. Most spiders have metabolic rates that are much lower than expected from body mass; but especially those with two pairs of lungs. Males normally have higher resting rates than females; spiders that are less evolved and possess a cribellum have lower metabolic rates than higher evolved species. Freely hunting spiders show a higher energy turnover than spiders hunting with a web. Spiders that live longer than 1 year will have lower metabolic rates than those species that die after 1 year in which development and reproduction must be completed. Lower temperatures and starvation, which most spiders can cope with, will decrease the metabolic rate as well.

  3. About phosphorylation of lappaconitine

    International Nuclear Information System (INIS)

    Burdelnaya, E.V.; Turmukhambetov, A.Zh.

    2005-01-01

    In the article chemical modifications of alkaloid lappaconitine are investigated. It was shown that synthesis of the phosphorylated derivatives are the ways to create new biologically active compounds. Interaction of lappaconitine with phosphorus pentachloride was used to obtain new phosphoric derivatives of alkaloid. The composition and structure of the new phosphorus-containing compounds were confirmed by elemental analysis: IR, UV and 13 C, 1 H, 31 P NMR -spectroscopy

  4. Estimation of microbial respiration rates in groundwater by geochemical modeling constrained with stable isotopes

    International Nuclear Information System (INIS)

    Murphy, E.M.

    1998-01-01

    Changes in geochemistry and stable isotopes along a well-established groundwater flow path were used to estimate in situ microbial respiration rates in the Middendorf aquifer in the southeastern United States. Respiration rates were determined for individual terminal electron acceptors including O 2 , MnO 2 , Fe 3+ , and SO 4 2- . The extent of biotic reactions were constrained by the fractionation of stable isotopes of carbon and sulfur. Sulfur isotopes and the presence of sulfur-oxidizing microorganisms indicated that sulfate is produced through the oxidation of reduced sulfur species in the aquifer and not by the dissolution of gypsum, as previously reported. The respiration rates varied along the flow path as the groundwater transitioned between primarily oxic to anoxic conditions. Iron-reducing microorganisms were the largest contributors to the oxidation of organic matter along the portion of the groundwater flow path investigated in this study. The transition zone between oxic and anoxic groundwater contained a wide range of terminal electron acceptors and showed the greatest diversity and numbers of culturable microorganisms and the highest respiration rates. A comparison of respiration rates measured from core samples and pumped groundwater suggests that variability in respiration rates may often reflect the measurement scales, both in the sample volume and the time-frame over which the respiration measurement is averaged. Chemical heterogeneity may create a wide range of respiration rates when the scale of the observation is below the scale of the heterogeneity

  5. Mitochondrial Respiration and Oxygen Tension.

    Science.gov (United States)

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

    2017-01-01

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

  6. Respirable versus inhalable dust sampling

    International Nuclear Information System (INIS)

    Hondros, J.

    1987-01-01

    The ICRP uses a total inhalable dust figure as the basis of calculations on employee lung dose. This paper was written to look at one aspect of the Olympic Dam dust situation, namely, the inhalable versus respirable fraction of the dust cloud. The results of this study will determine whether it is possible to use respirable dust figures, as obtained during routine monitoring to help in the calculations of employee exposure to internal radioactive contaminants

  7. Interpreting, measuring, and modeling soil respiration

    Science.gov (United States)

    Michael G. Ryan; Beverly E. Law

    2005-01-01

    This paper reviews the role of soil respiration in determining ecosystem carbon balance, and the conceptual basis for measuring and modeling soil respiration. We developed it to provide background and context for this special issue on soil respiration and to synthesize the presentations and discussions at the workshop. Soil respiration is the largest component of...

  8. A mechanical breathing simulator for respirator test

    International Nuclear Information System (INIS)

    Murata, Mikio; Ikezawa, Yoshio; Yoshida, Yoshikazu

    1976-01-01

    A mechanical breathing simulator has been developed to produce the human respiration for use in respirator test. The respirations were produced through the strokes of piston controlled by a rockerarm with adjustable fulcrum. The respiration rate was governed by motor-speed control, independent of the tidal volume achieved by adjustment of the piston stroke. By the breather, the simulated respirations for work rate 0, 208, 415, 622 and 830 kg-m/min could be produced through the typical dummy head. (auth.)

  9. Occurrence of trace elements in respirable coal dust

    International Nuclear Information System (INIS)

    Sahoo, B.N.

    1991-01-01

    Inhalation of fine particles of coal dust contributes significantly to the occurrence of the disease, pneumoconiosis, prevailing in coal mining community. It is not presently known whether only the coal dust or specific chemical compounds or synergistic effects of several compounds associated with respirable coal dust is responsible for the disease, pneumoconiosis. The present paper describes the quantitative determination of ten minor and trace elements in respirable coal dust particles by atomic absorption spectrophotometric methods. The respirable coal dust samples are collected at the mine atmosphere during drilling in coal scams by using Messrs. Casella's Hexlet apparatus specially designed and fitted with horizontal elutriator to collect the respirable coal dust fraction simulating as near as possible to the lung's retention of the coal miners. After destruction of organic matter by wet oxidation and filtering off clay and silica, Fe, Ca, Mg, Na, K, Mn, Cu, Zn, Cd, and Ni were determined directly in the resulting solution by atomic absorption spectrophotometric procedures. The results show that the trace metals are more acute in lower range of size spectrum. Correlation coefficient, enrichment factor and linear regression values and their inverse relationship between the slope and EF values suggest that, in general, the trace metals in respirable particulates are likely to be from coal derived source if their concentrations are likewise high in the coal. The trace metal analytical data of respirable particulates fitted well to the linear regressive equation. The results of the studies are of importance as it may throw some light on the respirable lung disease 'pneumoconiosis' which are predominant in coal mining community. (author). 13 refs., 6 tabs

  10. Phosphatidylserine transport by Ups2-Mdm35 in respiration-active mitochondria.

    Science.gov (United States)

    Miyata, Non; Watanabe, Yasunori; Tamura, Yasushi; Endo, Toshiya; Kuge, Osamu

    2016-07-04

    Phosphatidylethanolamine (PE) is an essential phospholipid for mitochondrial functions and is synthesized mainly by phosphatidylserine (PS) decarboxylase at the mitochondrial inner membrane. In Saccharomyces cerevisiae, PS is synthesized in the endoplasmic reticulum (ER), such that mitochondrial PE synthesis requires PS transport from the ER to the mitochondrial inner membrane. Here, we provide evidence that Ups2-Mdm35, a protein complex localized at the mitochondrial intermembrane space, mediates PS transport for PE synthesis in respiration-active mitochondria. UPS2- and MDM35-null mutations greatly attenuated conversion of PS to PE in yeast cells growing logarithmically under nonfermentable conditions, but not fermentable conditions. A recombinant Ups2-Mdm35 fusion protein exhibited phospholipid-transfer activity between liposomes in vitro. Furthermore, UPS2 expression was elevated under nonfermentable conditions and at the diauxic shift, the metabolic transition from glycolysis to oxidative phosphorylation. These results demonstrate that Ups2-Mdm35 functions as a PS transfer protein and enhances mitochondrial PE synthesis in response to the cellular metabolic state. © 2016 Miyata et al.

  11. Properties of phosphorylated thymidylate synthase

    DEFF Research Database (Denmark)

    Frączyk, Tomasz; Ruman, Tomasz; Wilk, Piotr

    2015-01-01

    by (31)P NMR to be modified only on histidine residues, like potassium phosphoramidate (KPA)-phosphorylated TS proteins. NanoLC-MS/MS, enabling the use of CID and ETD peptide fragmentation methods, identified several phosphohistidine residues, but certain phosphoserine and phosphothreonine residues were...... also implicated. Molecular dynamics studies, based on the mouse TS crystal structure, allowed one to assess potential of several phosphorylated histidine residues to affect catalytic activity, the effect being phosphorylation site dependent....

  12. Facepiece leakage and fitting of respirators

    International Nuclear Information System (INIS)

    White, J.M.

    1978-05-01

    The ways in which airborne contaminants can penetrate respirators and the factors which affect the fit of respirators are discussed. The fit of the respirator to the face is shown to be the most critical factor affecting the protection achieved by the user. Qualitative and quantitative fit testing techniques are described and their application to industrial respirator programs is examined. Quantitative measurement of the leakage of a respirator while worn can be used to numerically indicate the protection achieved. These numbers, often referred to as protection factors, are sometimes used as the basis for selecting suitable respirators and this practice is reviewed. (author)

  13. General Instructions for Disposable Respirators

    Centers for Disease Control (CDC) Podcasts

    2009-04-09

    This podcast, intended for the general public, demonstrates how to put on and take off disposable respirators that are to be used in areas affected by the influenza outbreak.  Created: 4/9/2009 by CDC, National Institute for Occupational Safety and Health (NIOSH).   Date Released: 4/29/2009.

  14. Use of Facemasks and Respirators

    Centers for Disease Control (CDC) Podcasts

    2007-05-15

    This program demonstrates the differences of facemasks and respirators that are to be used in public settings during an influenza pandemic.  Created: 5/15/2007 by CDC, National Institute for Occupational Safety and Health (NIOSH).   Date Released: 5/25/2007.

  15. Phosphorylation of chicken growth hormone

    International Nuclear Information System (INIS)

    Aramburo, C.; Montiel, J.L.; Donoghue, D.; Scanes, C.G.; Berghman, L.R.

    1990-01-01

    The possibility that chicken growth hormone (cGH) can be phosphorylated has been examined. Both native and biosynthetic cGH were phosphorylated by cAMP-dependent protein kinase (and γ- 32 P-ATP). The extent of phosphorylation was however less than that observed with ovine prolactin. Under the conditions employed, glycosylated cGH was not phosphorylated. Chicken anterior pituitary cells in primary culture were incubated in the presence of 32 P-phosphate. Radioactive phosphate was incorporated in vitro into the fraction immunoprecipitable with antisera against cGH. Incorporation was increased with cell number and time of incubation. The presence of GH releasing factor (GRF) increased the release of 32 P-phosphate labeled immunoprecipitable GH into the incubation media but not content of immunoprecipitable GH in the cells. The molecular weight of the phosphorylated immunoreactive cGH in the cells corresponded to cGH dimer

  16. Mitochondrial Respiration Is Reduced in Atherosclerosis, Promoting Necrotic Core Formation and Reducing Relative Fibrous Cap Thickness.

    Science.gov (United States)

    Yu, Emma P K; Reinhold, Johannes; Yu, Haixiang; Starks, Lakshi; Uryga, Anna K; Foote, Kirsty; Finigan, Alison; Figg, Nichola; Pung, Yuh-Fen; Logan, Angela; Murphy, Michael P; Bennett, Martin

    2017-12-01

    Mitochondrial DNA (mtDNA) damage is present in murine and human atherosclerotic plaques. However, whether endogenous levels of mtDNA damage are sufficient to cause mitochondrial dysfunction and whether decreasing mtDNA damage and improving mitochondrial respiration affects plaque burden or composition are unclear. We examined mitochondrial respiration in human atherosclerotic plaques and whether augmenting mitochondrial respiration affects atherogenesis. Human atherosclerotic plaques showed marked mitochondrial dysfunction, manifested as reduced mtDNA copy number and oxygen consumption rate in fibrous cap and core regions. Vascular smooth muscle cells derived from plaques showed impaired mitochondrial respiration, reduced complex I expression, and increased mitophagy, which was induced by oxidized low-density lipoprotein. Apolipoprotein E-deficient (ApoE -/- ) mice showed decreased mtDNA integrity and mitochondrial respiration, associated with increased mitochondrial reactive oxygen species. To determine whether alleviating mtDNA damage and increasing mitochondrial respiration affects atherogenesis, we studied ApoE -/- mice overexpressing the mitochondrial helicase Twinkle (Tw + /ApoE -/- ). Tw + /ApoE -/- mice showed increased mtDNA integrity, copy number, respiratory complex abundance, and respiration. Tw + /ApoE -/- mice had decreased necrotic core and increased fibrous cap areas, and Tw + /ApoE -/- bone marrow transplantation also reduced core areas. Twinkle increased vascular smooth muscle cell mtDNA integrity and respiration. Twinkle also promoted vascular smooth muscle cell proliferation and protected both vascular smooth muscle cells and macrophages from oxidative stress-induced apoptosis. Endogenous mtDNA damage in mouse and human atherosclerosis is associated with significantly reduced mitochondrial respiration. Reducing mtDNA damage and increasing mitochondrial respiration decrease necrotic core and increase fibrous cap areas independently of changes in

  17. 78 FR 18535 - Respirator Certification Fees

    Science.gov (United States)

    2013-03-27

    ... facepiece respirators. The North American respiratory protection market generated revenues around $1,830 million in 2007, the most recent data available.\\4\\ A summary of market segmentation, by respirator type... management. Of the U.S. respirator market of products approved by NIOSH, approximately 35 percent of approval...

  18. Band 3 Erythrocyte Membrane Protein Acts as Redox Stress Sensor Leading to Its Phosphorylation by p72 Syk

    Directory of Open Access Journals (Sweden)

    Antonella Pantaleo

    2016-01-01

    Full Text Available In erythrocytes, the regulation of the redox sensitive Tyr phosphorylation of band 3 and its functions are still partially defined. A role of band 3 oxidation in regulating its own phosphorylation has been previously suggested. The current study provides evidences to support this hypothesis: (i in intact erythrocytes, at 2 mM concentration of GSH, band 3 oxidation, and phosphorylation, Syk translocation to the membrane and Syk phosphorylation responded to the same micromolar concentrations of oxidants showing identical temporal variations; (ii the Cys residues located in the band 3 cytoplasmic domain are 20-fold more reactive than GSH; (iii disulfide linked band 3 cytoplasmic domain docks Syk kinase; (iv protein Tyr phosphatases are poorly inhibited at oxidant concentrations leading to massive band 3 oxidation and phosphorylation. We also observed that hemichromes binding to band 3 determined its irreversible oxidation and phosphorylation, progressive hemolysis, and serine hyperphosphorylation of different cytoskeleton proteins. Syk inhibitor suppressed the phosphorylation of band 3 also preventing serine phosphorylation changes and hemolysis. Our data suggest that band 3 acts as redox sensor regulating its own phosphorylation and that hemichromes leading to the protracted phosphorylation of band 3 may trigger a cascade of events finally leading to hemolysis.

  19. Effect of phosphorylation on antioxidant activities of pumpkin (Cucurbita pepo, Lady godiva) polysaccharide.

    Science.gov (United States)

    Song, Yi; Ni, Yuanying; Hu, Xiaosong; Li, Quanhong

    2015-11-01

    Phosphorylated derivatives of pumpkin polysaccharide with different degree of substitution were synthesized using POCl3 and pyridine. Antioxidant activities and cytoprotective effects of unmodified polysaccharide and phosphorylated derivatives were investigated employing various in vitro systems. Results showed that high ratio of POCl3/pyridine could increase the degree of substitution and no remarkable degradation occurred in the phosphorylation process. Characteristic absorption of phosphorylation appeared both in the IR and (31)P NMR spectrum. The df values between 2.27 and 2.55 indicated the relatively expanded conformation of the phosphorylated derivatives. All the phosphorylated polysaccharides exhibited higher antioxidant activities. H2O2-induced oxidative damages on rat thymic lymphocyte were also prevented by the derivatives. In general, phosphorylation could improve the antioxidant activities of pumpkin polysaccharide both in vitro and in a cell system. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Metformin induces oxidative stress in white adipocytes and raises uncoupling protein 2 levels.

    Science.gov (United States)

    Anedda, Andrea; Rial, Eduardo; González-Barroso, M Mar

    2008-10-01

    Metformin is a drug widely used to treat type 2 diabetes. It enhances insulin sensitivity by improving glucose utilization in tissues like liver or muscle. Metformin inhibits respiration, and the decrease in cellular energy activates the AMP-activated protein kinase that in turn switches on catabolic pathways. Moreover, metformin increases lipolysis and beta-oxidation in white adipose tissue, thereby reducing the triglyceride stores. The uncoupling proteins (UCPs) are transporters that lower the efficiency of mitochondrial oxidative phosphorylation. UCP2 is thought to protect against oxidative stress although, alternatively, it could play an energy dissipation role. The aim of this work was to analyse the involvement of UCP2 on the effects of metformin in white adipocytes. We studied the effect of this drug in differentiating 3T3-L1 adipocytes and found that metformin causes oxidative stress since it increases the levels of reactive oxygen species (ROS) and lowers the aconitase activity. Variations in UCP2 protein levels parallel those of ROS. Metformin also increases lipolysis in these cells although only when the levels of ROS and UCP2 have decreased. Hence, UCP2 does not appear to be needed to facilitate fatty acid oxidation. Furthermore, treatment of C57BL/6 mice with metformin also augmented the levels of UCP2 in epididymal white adipose tissue. We conclude that metformin treatment leads to the overexpression of UCP2 in adipocytes to minimize the oxidative stress that is probably due to the inhibition of respiration caused by the drug.

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

    Science.gov (United States)

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

    2015-11-01

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

  2. Contribution of Root Respiration to Soil Respiration in Sugarcane Plantation in Thailand

    OpenAIRE

    Wilaiwan Sornpoon; Sebastien Bonnet; Poonpipope Kasemsap; Savitri Garivait

    2013-01-01

    The understanding on the contribution of root respiration to total soil respiration is still very limited, especially for sugarcane. In this study, trenching experiments in sugarcane plantations were conducted to separate and investigate soil respiration for this crop. The measurements were performed for the whole growing period of 344 days to quantify root respiration. The obtained monitoring data showed that the respiration rate is increasing with the age of the plant, accounting for up to ...

  3. Role of phosphate and other proton-donating anions in respiration-coupled transport of Ca2+ by mitochondria.

    Science.gov (United States)

    Lehninger, A L

    1974-04-01

    Measurements of extra oxygen consumption, (45)Ca(2+) uptake, and the osmotic expansion of the matrix compartment show that not all permeant anions are capable of supporting and accompanying the energy-dependent transport of Ca(2+) from the medium into the matrix in respiring rat-liver mitochondria. Phosphate, arsenate, acetate, butyrate, beta-hydroxybutyrate, lactate, and bicarbonate + CO(2) supported Ca(2+) uptake, whereas the permeant anions, nitrate, thiocyanate, chlorate, and perchlorate, did not. The active anions share a common denominator, the potential ability to donate a proton to the mitochondrial matrix; the inactive anions lack this capacity. Phosphate and the other active permeant anions move into the matrix in response to the alkaline-inside electrochemical gradient of protons generated across the mitochondrial membrane by electron transport, thus forming a negative-inside anion gradient. It is postulated that the latter gradient is the immediate "pulling" force for the influx of Ca(2+) on the electrogenic Ca(2+) carrier in respiring mitochondria under intracellular conditions. Since mitochondria in the cell are normally exposed to an excess of phosphate (and the bicarbonate-CO(2) system), particularly in state 4, inward transport of these proton-yielding anions probably precedes and is necessary for inward transport of Ca(2+) and other cations under biological conditions. These observations indicate that a negative-inside gradient of phosphate generated by electron transport is a common step and provides the immediate motive power not only for (a) the inward transport of dicarboxylates and tricarboxylates and (b) the energy-dependent exchange of external ADP(3-) for internal ATP(4-) during oxidative phosphorylation, as has already been established, but also for (c) the inward transport of Ca(2+), K(+), and other cations.

  4. Lymphocyte respiration in children with Trisomy 21

    Directory of Open Access Journals (Sweden)

    Aburawi Elhadi H

    2012-12-01

    Full Text Available Abstract Background This study measured lymphocyte mitochondrial O2 consumption (cellular respiration in children with trisomy 21. Methods Peripheral blood mononuclear cells were isolated from whole blood of trisomy 21 and control children and these cells were immediately used to measure cellular respiration rate. [O2] was determined as a function of time from the phosphorescence decay rates (1/τ of Pd (II-meso-tetra-(4-sulfonatophenyl-tetrabenzoporphyrin. In sealed vials containing lymphocytes and glucose as a respiratory substrate, [O2] declined linearly with time, confirming the zero-order kinetics of O2 conversion to H2O by cytochrome oxidase. The rate of respiration (k, in μM O2 min-1, thus, was the negative of the slope of [O2] vs. time. Cyanide inhibited O2 consumption, confirming that oxidation occurred in the mitochondrial respiratory chain. Results For control children (age = 8.8 ± 5.6 years, n = 26, the mean (± SD value of kc (in μM O2 per min per 107 cells was 1.36 ± 0.79 (coefficient of variation, Cv = 58%; median = 1.17; range = 0.60 to 3.12; -2SD = 0.61. For children with trisomy 21 (age = 7.2 ± 4.6 years, n = 26, the values of kc were 0.82 ± 0.62 (Cv = 76%; median = 0.60; range = 0.20 to 2.80, pp6.1 mU/L. Fourteen of 26 (54% children with trisomy 21 had kc values of 0.20 to 0.60 (i.e., kc positively correlated with body-mass index (BMI, R >0.302, serum creatinine (R >0.507, blood urea nitrogen (BUN, R >0.535 and albumin (R >0.446. Conclusions Children with trisomy 21 in this study have reduced lymphocyte bioenergetics. The clinical importance of this finding requires further studies.

  5. Cisplatin cytotoxicity is dependent on mitochondrial respiration in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Santhipriya Inapurapu

    2017-01-01

    Full Text Available Objective(s: To understand the role of mitochondrial respiration in cisplatin sensitivity, we have employed wild-type and mitochondrial DNA depleted Rho0 yeast cells. Materials and Methods: Wild type and Rho0 yeast cultured in fermentable and non-fermentable sugar containing media, were studied for their sensitivity against cisplatin by monitoring growth curves, oxygen consumption, pH changes in cytosol/mitochondrial compartments, reactive oxygen species production and respiratory control ratio. Results: Wild-type yeast grown on glycerol exhibited heightened sensitivity to cisplatin than yeast grown on glucose. Cisplatin (100 μM, although significantly reduced the growth of wild- type cells, only slightly altered the growth rate of Rho0 cells. Cisplatin treatment decreased both pHcyt and pHmit to a similar extent without affecting the pH difference. Cisplatin dose-dependently increased the oxidative stress in wild-type, but not in respiration-deficient Rho0 strain. Cisplatin decreased the respiratory control ratio. Conclusion: These results suggest that cisplatin toxicity is influenced by the respiratory capacity of the cells and the intracellular oxidative burden. Although cisplatin per se slightly decreased the respiration of yeast cells grown in glucose, it did not disturb the mitochondrial chemiosmotic gradient.

  6. Hyperoxia decreases glycolytic capacity, glycolytic reserve and oxidative phosphorylation in MLE-12 cells and inhibits complex I and II function, but not complex IV in isolated mouse lung mitochondria.

    Directory of Open Access Journals (Sweden)

    Kumuda C Das

    Full Text Available High levels of oxygen (hyperoxia are frequently used in critical care units and in conditions of respiratory insufficiencies in adults, as well as in infants. However, hyperoxia has been implicated in a number of pulmonary disorders including bronchopulmonary dysplasia (BPD and adult respiratory distress syndrome (ARDS. Hyperoxia increases the generation of reactive oxygen species (ROS in the mitochondria that could impair the function of the mitochondrial electron transport chain. We analyzed lung mitochondrial function in hyperoxia using the XF24 analyzer (extracellular flux and optimized the assay for lung epithelial cells and mitochondria isolated from lungs of mice. Our data show that hyperoxia decreases basal oxygen consumption rate (OCR, spare respiratory capacity, maximal respiration and ATP turnover in MLE-12 cells. There was significant decrease in glycolytic capacity and glycolytic reserve in MLE-12 cells exposed to hyperoxia. Using mitochondria isolated from lungs of mice exposed to hyperoxia or normoxia we have shown that hyperoxia decreased the basal, state 3 and state3 μ (respiration in an uncoupled state respirations. Further, using substrate or inhibitor of a specific complex we show that the OCR via complex I and II, but not complex IV was decreased, demonstrating that complexes I and II are specific targets of hyperoxia. Further, the activities of complex I (NADH dehydrogenase, NADH-DH and complex II (succinate dehydrogenase, SDH were decreased in hyperoxia, but the activity of complex IV (cytochrome oxidase, COX remains unchanged. Taken together, our study show that hyperoxia impairs glycolytic and mitochondrial energy metabolism in in tact cells, as well as in lungs of mice by selectively inactivating components of electron transport system.

  7. Management effects on European cropland respiration

    DEFF Research Database (Denmark)

    Eugster, Werner; Moffat, Antje M.; Ceschia, Eric

    2010-01-01

    Increases in respiration rates following management activities in croplands are considered a relevant anthropogenic source of CO2. In this paper, we quantify the impact of management events on cropland respiration fluxes of CO2 as they occur under current climate and management conditions. Our....... This allowed us to address the question of how management activities influence ecosystem respiration. This was done by comparing respiration fluxes during 7, 14, and 28 days after the management with those observed during the matching time period before management. Median increases in respiration ranged from...... than management alone are also important at a given site. Temperature is the climatic factor that showed best correlation with site-specific respiration fluxes. Therefore, the effect of temperature changes between the time periods before and after management were taken into account for a subset of 13...

  8. Effects of respirator use on worker performance

    Energy Technology Data Exchange (ETDEWEB)

    Cardarelli, R. [Yankee Atomic Electric Co., Bolton, MA (United States)

    1995-03-01

    In 1993, EPRI funded Yankee Atomic Electric Company to examine the effects of respirator use on worker efficiency. Phase I of Yankee`s effort was to develop a study design to determine respirator effects. Given success in Phase I, a larger population will be tested to determine if a stasitically significant respirator effect on performance can be measured. This paper summarizes the 1993 EPRI/Yankee Respirator Effects of Pilot Study, and describes the study design for the 1994 EPRI/Yankee Respirator Study to be conducted at the Oyster Creek Nuclear Power Plant. Also described is a summary of respirator effect studies that have been conducted during the last ten (10) years.

  9. SMG-1 kinase attenuates mitochondrial ROS production but not cell respiration deficits during hyperoxia.

    Science.gov (United States)

    Resseguie, Emily A; Brookes, Paul S; O'Reilly, Michael A

    Supplemental oxygen (hyperoxia) used to treat individuals in respiratory distress causes cell injury by enhancing the production of toxic reactive oxygen species (ROS) and inhibiting mitochondrial respiration. The suppressor of morphogenesis of genitalia (SMG-1) kinase is activated during hyperoxia and promotes cell survival by phosphorylating the tumor suppressor p53 on serine 15. Here, we investigate whether SMG-1 and p53 blunt this vicious cycle of progressive ROS production and decline in mitochondrial respiration seen during hyperoxia. Human lung adenocarcinoma A549 and H1299 or colon carcinoma HCT116 cells were depleted of SMG-1, UPF-1, or p53 using RNA interference, and then exposed to room air (21% oxygen) or hyperoxia (95% oxygen). Immunoblotting was used to evaluate protein expression; a Seahorse Bioanalyzer was used to assess cellular respiration; and flow cytometry was used to evaluate fluorescence intensity of cells stained with mitochondrial or redox sensitive dyes. Hyperoxia increased mitochondrial and cytoplasmic ROS and suppressed mitochondrial respiration without changing mitochondrial mass or membrane potential. Depletion of SMG-1 or its cofactor, UPF1, significantly enhanced hyperoxia-induced mitochondrial but not cytosolic ROS abundance. They did not affect mitochondrial mass, membrane potential, or hyperoxia-induced deficits in mitochondrial respiration. Genetic depletion of p53 in A549 cells and ablation of the p53 gene in H1299 or HCT116 cells revealed that SMG-1 influences mitochondrial ROS through activation of p53. Our findings show that hyperoxia does not promote a vicious cycle of progressive mitochondrial ROS and dysfunction because SMG-1-p53 signaling attenuates production of mitochondrial ROS without preserving respiration. This suggests antioxidant therapies that blunt ROS production during hyperoxia may not suffice to restore cellular respiration.

  10. Respirators: Supervisors Self-Study #43442

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-20

    This course, Respirators: Supervisors Self-Study (#43442), addresses training requirements for supervisors of respirator wearers as specified by the American National Standard Institute (ANSI) Standard for Respiratory Protection, ANSI Z88.2, and as incorporated by reference in the Department of Energy (DOE) Worker Health and Safety Rule, 10 Code of Federal Regulations (CFR) 851. This course also presents the responsibilities of supervisors of respirator wearers at Los Alamos National Laboratory (LANL).

  11. Glycogen phosphorylation and Lafora disease.

    Science.gov (United States)

    Roach, Peter J

    2015-12-01

    Covalent phosphorylation of glycogen, first described 35 years ago, was put on firm ground through the work of the Whelan laboratory in the 1990s. But glycogen phosphorylation lay fallow until interest was rekindled in the mid 2000s by the finding that it could be removed by a glycogen-binding phosphatase, laforin, and that mutations in laforin cause a fatal teenage-onset epilepsy, called Lafora disease. Glycogen phosphorylation is due to phosphomonoesters at C2, C3 and C6 of glucose residues. Phosphate is rare, ranging from 1:500 to 1:5000 phosphates/glucose depending on the glycogen source. The mechanisms of glycogen phosphorylation remain under investigation but one hypothesis to explain C2 and perhaps C3 phosphate is that it results from a rare side reaction of the normal synthetic enzyme glycogen synthase. Lafora disease is likely caused by over-accumulation of abnormal glycogen in insoluble deposits termed Lafora bodies in neurons. The abnormality in the glycogen correlates with elevated phosphorylation (at C2, C3 and C6), reduced branching, insolubility and an enhanced tendency to aggregate and become insoluble. Hyperphosphorylation of glycogen is emerging as an important feature of this deadly childhood disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Model Construction and Analysis of Respiration in Halobacterium salinarum.

    Directory of Open Access Journals (Sweden)

    Cherryl O Talaue

    Full Text Available The archaeon Halobacterium salinarum can produce energy using three different processes, namely photosynthesis, oxidative phosphorylation and fermentation of arginine, and is thus a model organism in bioenergetics. Compared to its bacteriorhodopsin-driven photosynthesis, less attention has been devoted to modeling its respiratory pathway. We created a system of ordinary differential equations that models its oxidative phosphorylation. The model consists of the electron transport chain, the ATP synthase, the potassium uniport and the sodium-proton antiport. By fitting the model parameters to experimental data, we show that the model can explain data on proton motive force generation, ATP production, and the charge balancing of ions between the sodium-proton antiporter and the potassium uniport. We performed sensitivity analysis of the model parameters to determine how the model will respond to perturbations in parameter values. The model and the parameters we derived provide a resource that can be used for analytical studies of the bioenergetics of H. salinarum.

  13. Model Construction and Analysis of Respiration in Halobacterium salinarum.

    Science.gov (United States)

    Talaue, Cherryl O; del Rosario, Ricardo C H; Pfeiffer, Friedhelm; Mendoza, Eduardo R; Oesterhelt, Dieter

    2016-01-01

    The archaeon Halobacterium salinarum can produce energy using three different processes, namely photosynthesis, oxidative phosphorylation and fermentation of arginine, and is thus a model organism in bioenergetics. Compared to its bacteriorhodopsin-driven photosynthesis, less attention has been devoted to modeling its respiratory pathway. We created a system of ordinary differential equations that models its oxidative phosphorylation. The model consists of the electron transport chain, the ATP synthase, the potassium uniport and the sodium-proton antiport. By fitting the model parameters to experimental data, we show that the model can explain data on proton motive force generation, ATP production, and the charge balancing of ions between the sodium-proton antiporter and the potassium uniport. We performed sensitivity analysis of the model parameters to determine how the model will respond to perturbations in parameter values. The model and the parameters we derived provide a resource that can be used for analytical studies of the bioenergetics of H. salinarum.

  14. Carnosine inhibits the proliferation of human gastric cancer SGC-7901 cells through both of the mitochondrial respiration and glycolysis pathways.

    Directory of Open Access Journals (Sweden)

    Yao Shen

    Full Text Available Carnosine, a naturally occurring dipeptide, has been recently demonstrated to possess anti-tumor activity. However, its underlying mechanism is unclear. In this study, we investigated the effect and mechanism of carnosine on the cell viability and proliferation of the cultured human gastric cancer SGC-7901 cells. Carnosine treatment did not induce cell apoptosis or necrosis, but reduced the proliferative capacity of SGC-7901 cells. Seahorse analysis showed SGC-7901 cells cultured with pyruvate have active mitochondria, and depend on mitochondrial oxidative phosphorylation more than glycolysis pathway for generation of ATP. Carnosine markedly decreased the absolute value of mitochondrial ATP-linked respiration, and reduced the maximal oxygen consumption and spare respiratory capacity, which may reduce mitochondrial function correlated with proliferative potential. Simultaneously, carnosine also reduced the extracellular acidification rate and glycolysis of SGC-7901 cells. Our results suggested that carnosine is a potential regulator of energy metabolism of SGC-7901 cells both in the anaerobic and aerobic pathways, and provided a clue for preclinical and clinical evaluation of carnosine for gastric cancer therapy.

  15. Propofol directly increases tau phosphorylation.

    Directory of Open Access Journals (Sweden)

    Robert A Whittington

    2011-01-01

    Full Text Available In Alzheimer's disease (AD and other tauopathies, the microtubule-associated protein tau can undergo aberrant hyperphosphorylation potentially leading to the development of neurofibrillary pathology. Anesthetics have been previously shown to induce tau hyperphosphorylation through a mechanism involving hypothermia-induced inhibition of protein phosphatase 2A (PP2A activity. However, the effects of propofol, a common clinically used intravenous anesthetic, on tau phosphorylation under normothermic conditions are unknown. We investigated the effects of a general anesthetic dose of propofol on levels of phosphorylated tau in the mouse hippocampus and cortex under normothermic conditions. Thirty min following the administration of propofol 250 mg/kg i.p., significant increases in tau phosphorylation were observed at the AT8, CP13, and PHF-1 phosphoepitopes in the hippocampus, as well as at AT8, PHF-1, MC6, pS262, and pS422 epitopes in the cortex. However, we did not detect somatodendritic relocalization of tau. In both brain regions, tau hyperphosphorylation persisted at the AT8 epitope 2 h following propofol, although the sedative effects of the drug were no longer evident at this time point. By 6 h following propofol, levels of phosphorylated tau at AT8 returned to control levels. An initial decrease in the activity and expression of PP2A were observed, suggesting that PP2A inhibition is at least partly responsible for the hyperphosphorylation of tau at multiple sites following 30 min of propofol exposure. We also examined tau phosphorylation in SH-SY5Y cells transfected to overexpress human tau. A 1 h exposure to a clinically relevant concentration of propofol in vitro was also associated with tau hyperphosphorylation. These findings suggest that propofol increases tau phosphorylation both in vivo and in vitro under normothermic conditions, and further studies are warranted to determine the impact of this anesthetic on the acceleration of

  16. [Effects of Tillage on Soil Respiration and Root Respiration Under Rain-Fed Summer Corn Field].

    Science.gov (United States)

    Lu, Xing-li; Liao, Yun-cheng

    2015-06-01

    To explore the effects of different tillage systems on soil respiration and root respiration under rain-fed condition. Based on a short-term experiment, this paper investigated soil respiration in summer corn growth season under four tillage treatments including subsoiling tillage (ST), no tillage (NT), rotary tillage (RT) and moldboard plow tillage (CT). The contribution of root respiration using root exclusion method was also discussed. The results showed that soil respiration rate presented a single peak trend under four tillage methods during the summer corn growing season, and the maximum value was recorded at the heading stage. The trends of soil respiration were as follows: heading stage > flowering stage > grain filling stage > maturity stage > jointing stage > seedling stage. The trends of soil respiration under different tillage systems were as follows: CT > ST > RT > NT. There was a significant correlation between soil respiration rate and soil temperatures (P soil respiration using exponential function equation. However, there was no significant correlation between soil respiration rate and soil moisture. Root respiration accounted for 45.13%-56.86% of the proportion of soil respiratio n with the mean value 51.72% during the summer corn growing season under different tillage systems. Therefore, root exclusion method could be used to study the contribution of crop growth to carbon emission, to compare effects of different tillage systems on the contribution of root respiration provides the bases for selecting the measures to slow down the decomposition of soil carbon.

  17. Molecular Characterization of Bacterial Respiration on Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Robert C.

    2013-04-26

    The overall aim of this project was to contribute to our fundamental understanding of proteins and biological processes under extreme environmental conditions. We sought to define the biochemical and physiological mechanisms that underlie biodegradative and other cellular processes in normal, extreme, and engineered environments. Toward that end, we sought to understand the substrate oxidation pathways, the electron transport mechanisms, and the modes of energy conservation employed during respiration by bacteria on soluble iron and insoluble sulfide minerals. In accordance with these general aims, the specific aims were two-fold: To identify, separate, and characterize the extracellular biomolecules necessary for aerobic respiration on iron under strongly acidic conditions; and to elucidate the molecular principles whereby these bacteria recognize and adhere to their insoluble mineral substrates under harsh environmental conditions. The results of these studies were described in a total of nineteen manuscripts. Highlights include the following: 1. The complete genome of Acidithiobacillus ferrooxidans ATCC 23270 (type strain) was sequenced in collaboration with the DOE Joint Genome Institute; 2. Genomic and mass spectrometry-based proteomic methods were used to evaluate gene expression and in situ microbial activity in a low-complexity natural acid mine drainage microbial biofilm community. This was the first effort to successfully analyze a natural community using these techniques; 3. Detailed functional and structural studies were conducted on rusticyanin, an acid-stable electron transfer protein purified from cell-free extracts of At. ferrooxidans. The three-dimensional structure of reduced rusticyanin was determined from a combination of homonuclear proton and heteronuclear 15N- and 13C-edited NMR spectra. Concomitantly, the three-dimensional structure of oxidized rusticyanin was determined by X-ray crystallography to a resolution of 1.9 A by multiwavelength

  18. Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

    Science.gov (United States)

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

    2016-11-07

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

  19. Elemental Concentration of Inhalable and Respirable Particulate ...

    African Journals Online (AJOL)

    20537 and respirable foam for I.O.M sampler. The elemental composition (Co, Ni, Zn, Cu, Fe, Pb, Cr, Mn and Cd) were analyzed by using Atomic Absorption Spectrophotometric (AAS). The data generated were subjected to descriptive analysis. In inhalable fraction,the enrichment factor ranged from 1-73.3 while in respirable ...

  20. Respirators: APR Issuer Self Study 33461

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Laboratory

    2016-07-13

    Respirators: APR Issuer Self-Study (course 33461) is designed to introduce and familiarize employees selected as air-purifying respirator (APR) issuers at Los Alamos National Laboratory (LANL) with the responsibilities, limitations, procedures, and resources for issuing APRs at LANL. The goal is to enable these issuers to consistently provide proper, functioning APRs to authorized users

  1. SYMPOSIUM ON PLANT PROTEIN PHOSPHORYLATION

    Energy Technology Data Exchange (ETDEWEB)

    JOHN C WALKER

    2011-11-01

    Protein phosphorylation and dephosphorylation play key roles in many aspects of plant biology, including control of cell division, pathways of carbon and nitrogen metabolism, pattern formation, hormonal responses, and abiotic and biotic responses to environmental signals. A Symposium on Plant Protein Phosphorylation was hosted on the Columbia campus of the University of Missouri from May 26-28, 2010. The symposium provided an interdisciplinary venue at which scholars studying protein modification, as it relates to a broad range of biological questions and using a variety of plant species, presented their research. It also provided a forum where current international challenges in studies related to protein phosphorylation could be examined. The symposium also stimulated research collaborations through interactions and networking among those in the research community and engaged students and early career investigators in studying issues in plant biology from an interdisciplinary perspective. The proposed symposium, which drew 165 researchers from 13 countries and 21 States, facilitated a rapid dissemination of acquired knowledge and technical expertise regarding protein phosphorylation in plants to a broad range of plant biologists worldwide.

  2. Tyrosine phosphorylation in human lymphomas

    NARCIS (Netherlands)

    Haralambieva, E; Jones, M.; Roncador, GM; Cerroni, L; Lamant, L; Ott, G; Rosenwald, A; Sherman, C; Thorner, P; Kusec, R; Wood, KM; Campo, E; Falini, B; Ramsay, A; Marafioti, T; Stein, H; Kluin, PM; Pulford, K; Mason, DY

    2002-01-01

    In a previous study, we showed that the high level of protein tyrosine phosphorylation present in lymphomas containing an anaplastic lymphoma kinase (ALK) can be demonstrated in routinely processed paraffin tissue sections using immunolabelling techniques. In the present study we investigated

  3. Lipid peroxidation and cytotoxicity induced by respirable volcanic ash

    Energy Technology Data Exchange (ETDEWEB)

    Cervini-Silva, Javiera, E-mail: jcervini@correo.cua.uam.mx [Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana Unidad Cuajimalpa, México City (Mexico); Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Nieto-Camacho, Antonio [Laboratorio de Pruebas Biológicas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Gomez-Vidales, Virginia [Laboratorio de Resonancia Paramagnética Electrónica, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Ramirez-Apan, María Teresa [Laboratorio de Pruebas Biológicas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Palacios, Eduardo; Montoya, Ascención [Dirección de Investigación y Posgrado, Instituto Mexicano del Petróleo (Mexico); Kaufhold, Stephan [BGR Bundesansaltfür Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover (Germany); and others

    2014-06-01

    Highlights: • Respirable volcanic ash induces oxidative degradation of lipids in cell membranes. • Respirable volcanic ash triggers cytotoxicity in murin monocyle/macrophage cells. • Oxidative stress is surface controlled but not restricted by surface- Fe{sup 3+}. • Surface Fe{sup 3+} acts as a stronger inductor in allophanes vs phyllosilicates or oxides. • Registered cell-viability values were as low as 68.5 ± 6.7%. - Abstract: This paper reports that the main component of respirable volcanic ash, allophane, induces lipid peroxidation (LP), the oxidative degradation of lipids in cell membranes, and cytotoxicity in murin monocyle/macrophage cells. Naturally-occurring allophane collected from New Zealand, Japan, and Ecuador was studied. The quantification of LP was conducted using the Thiobarbituric Acid Reactive Substances (TBARS) assay. The cytotoxic effect was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay. Electron-Paramagnetic Resonance (EPR) determinations of naturally-occurring allophane confirmed the incorporation in the structure and clustering of structural Fe{sup 3+}, and nucleation and growth of small-sized Fe (oxyhydr)oxide or gibbsite. LP induced by allophane varied with time, and solid concentration and composition, reaching 6.7 ± 0.2 nmol TBARS mg prot{sup −1}. LP was surface controlled but not restricted by structural or surface-bound Fe{sup 3+}, because redox processes induced by soluble components other than perferryl iron. The reactivity of Fe{sup 3+} soluble species stemming from surface-bound Fe{sup 3+} or small-sized Fe{sup 3+} refractory minerals in allophane surpassed that of structural Fe{sup 3+} located in tetrahedral or octahedral sites of phyllosilicates or bulk iron oxides. Desferrioxamine B mesylate salt (DFOB) or ethylenediaminetetraacetic acid (EDTA) inhibited LP. EDTA acted as a more effective inhibitor, explained by multiple electron transfer pathways. Registered cell

  4. Bioavailability assessment of contaminants in soils via respiration and nitrification tests

    International Nuclear Information System (INIS)

    Hund-Rinke, Kerstin; Simon, Markus

    2008-01-01

    For the assessment of contaminated soils ecotoxicological tests are used to estimate the bioavailability of contaminants in soil samples. Terrestrial tests reveal the habitat function of soils, and parameters applied in tests involving microorganisms include respiration activity and potential ammonium oxidation. For such tests, the threshold values needed to assess the results have already been established in guidelines ISO 17155 and ISO 15685. In this paper, we discuss about the respiration activity and potential ammonium oxidation results obtained from a wide variety of soils with different physico-chemical properties and levels of contamination. These results show that microbial respiration and potential ammonium oxidation have different sensitivities to various classes of contaminants. We demonstrated that both organic and inorganic contaminants influence potential ammonium oxidation, whereas microbial respiration is predominantly affected by biodegradable organic contaminants. These differences might be useful for more detailed assessments of soil contamination, leading to different recommended actions depending on which parameter is affected. - The paper provides a further criterion for a more detailed assessment of soil contamination, leading to different recommended actions depending on which parameter is affected

  5. Bioavailability assessment of contaminants in soils via respiration and nitrification tests

    Energy Technology Data Exchange (ETDEWEB)

    Hund-Rinke, Kerstin [Fraunhofer Institute for Molecular Biology and Applied Ecology, Auf dem Aberg 1, 57392 Schmallenberg (Germany)], E-mail: kerstin.hund-rinke@ime.fraunhofer.de; Simon, Markus [Fraunhofer Institute for Molecular Biology and Applied Ecology, Auf dem Aberg 1, 57392 Schmallenberg (Germany)], E-mail: markus.simon@ime.fraunhofer.de

    2008-05-15

    For the assessment of contaminated soils ecotoxicological tests are used to estimate the bioavailability of contaminants in soil samples. Terrestrial tests reveal the habitat function of soils, and parameters applied in tests involving microorganisms include respiration activity and potential ammonium oxidation. For such tests, the threshold values needed to assess the results have already been established in guidelines ISO 17155 and ISO 15685. In this paper, we discuss about the respiration activity and potential ammonium oxidation results obtained from a wide variety of soils with different physico-chemical properties and levels of contamination. These results show that microbial respiration and potential ammonium oxidation have different sensitivities to various classes of contaminants. We demonstrated that both organic and inorganic contaminants influence potential ammonium oxidation, whereas microbial respiration is predominantly affected by biodegradable organic contaminants. These differences might be useful for more detailed assessments of soil contamination, leading to different recommended actions depending on which parameter is affected. - The paper provides a further criterion for a more detailed assessment of soil contamination, leading to different recommended actions depending on which parameter is affected.

  6. Tyrosine phosphorylation of WW proteins

    Science.gov (United States)

    Reuven, Nina; Shanzer, Matan

    2015-01-01

    A number of key regulatory proteins contain one or two copies of the WW domain known to mediate protein–protein interaction via proline-rich motifs, such as PPxY. The Hippo pathway components take advantage of this module to transduce tumor suppressor signaling. It is becoming evident that tyrosine phosphorylation is a critical regulator of the WW proteins. Here, we review the current knowledge on the involved tyrosine kinases and their roles in regulating the WW proteins. PMID:25627656

  7. BOREAS TE-5 Soil Respiration Data

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

    2000-01-01

    The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. Soil respiration data were collected from 26-May-94 to 07-Sep-94 in the BOREAS NSA and SSA to compare the soil respiration rates in different forest sites using a LI-COR 6200 soil respiration chamber (model 6299). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

  8. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    International Nuclear Information System (INIS)

    Gross, Benjamin J.; El-Naggar, Mohamed Y.

    2015-01-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions

  9. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces.

    Science.gov (United States)

    Gross, Benjamin J; El-Naggar, Mohamed Y

    2015-06-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  10. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Benjamin J. [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); El-Naggar, Mohamed Y., E-mail: mnaggar@usc.edu [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-0484 (United States); Department of Chemistry, University of Southern California, Los Angeles, California 90089-0484 (United States)

    2015-06-15

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  11. The diabetes medication Canagliflozin reduces cancer cell proliferation by inhibiting mitochondrial complex-I supported respiration

    Directory of Open Access Journals (Sweden)

    Linda A. Villani

    2016-10-01

    Full Text Available Objective: The sodium-glucose transporter 2 (SGLT2 inhibitors Canagliflozin and Dapagliflozin are recently approved medications for type 2 diabetes. Recent studies indicate that SGLT2 inhibitors may inhibit the growth of some cancer cells but the mechanism(s remain unclear. Methods: Cellular proliferation and clonogenic survival were used to assess the sensitivity of prostate and lung cancer cell growth to the SGLT2 inhibitors. Oxygen consumption, extracellular acidification rate, cellular ATP, glucose uptake, lipogenesis, and phosphorylation of AMP-activated protein kinase (AMPK, acetyl-CoA carboxylase, and the p70S6 kinase were assessed. Overexpression of a protein that maintains complex-I supported mitochondrial respiration (NDI1 was used to establish the importance of this pathway for mediating the anti-proliferative effects of Canagliflozin. Results: Clinically achievable concentrations of Canagliflozin, but not Dapagliflozin, inhibit cellular proliferation and clonogenic survival of prostate and lung cancer cells alone and in combination with ionizing radiation and the chemotherapy Docetaxel. Canagliflozin reduced glucose uptake, mitochondrial complex-I supported respiration, ATP, and lipogenesis while increasing the activating phosphorylation of AMPK. The overexpression of NDI1 blocked the anti-proliferative effects of Canagliflozin indicating reductions in mitochondrial respiration are critical for anti-proliferative actions. Conclusion: These data indicate that like the biguanide metformin, Canagliflozin not only lowers blood glucose but also inhibits complex-I supported respiration and cellular proliferation in prostate and lung cancer cells. These observations support the initiation of studies evaluating the clinical efficacy of Canagliflozin on limiting tumorigenesis in pre-clinical animal models as well epidemiological studies on cancer incidence relative to other glucose lowering therapies in clinical populations. Keywords: AMP

  12. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC

    DEFF Research Database (Denmark)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B

    2012-01-01

    The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antib......The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho......-related proline-alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and m...

  13. How much work is expended for respiration?

    Science.gov (United States)

    Johnson, A T

    1993-01-01

    The rate of work expended to move air in the respiratory system has been determined for five different airflow waveshapes, a non-linear respiratory model and five exercise levels. As expected, the rectangular waveshape was the most efficient. Model conditions were then changed one a time: (i) starting lung volume was allowed to vary, (ii) exhalation flow limitation was added, (iii) respiration was considered to be a metabolic burden determining part of the ventilation requirement and (iv) a respirator mask was added. Although there is no direct work advantage to varying initial lung volume, such volume changes appear to be dictated by the asymmetry of lung recoil pressure about the lung relaxation volume; allowing the work of respiration to become a metabolic burden clearly shows why respiratory waveforms change from rest to exercise; and, adding a respirator imposes a severe respiratory burden on the wearer engaging in moderate, heavy and very heavy exercise.

  14. Separating rhizosphere respiration from total soil respiration in two larch plantations in northeastern China.

    Science.gov (United States)

    Jiang, Lifen; Shi, Fuchen; Li, Bo; Luo, Yiqi; Chen, Jiquan; Chen, Jiakuan

    2005-09-01

    The potential capacity of soil to sequester carbon in response to global warming is strongly regulated by the ratio of rhizosphere respiration to respiration by soil microbial decomposers, because of their different temperature sensitivities. To quantify relative contributions of rhizosphere respiration to total soil respiration as influenced by forest stand development, we conducted a trenching study in two larch (Larix gmelini (Rupr.) Rupr.) plantations, aged 17 and 31 years, in northeastern China. Four plots in each plantation were randomly selected and trenched in early May 2001. Soil surface CO2 effluxes both inside and outside the plots were measured from May 2001 to August 2002. Soil respiration (i.e., the CO2 effluxes outside the trenched plots) varied similarly in the two plantations from 0.8 micromol m(-2) s(-1) in winter to 6.0 micromol m(-2) s(-1) in summer. Rhizosphere respiration (i.e., CO2 efflux outside the trenched plots minus that inside the plots) varied from 0.2 to 2.0 micromol m(-2) s(-1) in the old forest and from 0.3 to 4.0 micromol m(-2) s(-1) in the young forest over the seasons. Rhizosphere respiration, on average, accounted for 25% of soil respiration in the old forest and 65% in the young forest. Rhizosphere and soil respiration were significantly correlated with soil temperature but not with soil water content. We conclude that the role forests play in regulating climate change may depend on their age.

  15. Repression of mitochondrial translation, respiration and a metabolic cycle-regulated gene, SLF1, by the yeast Pumilio-family protein Puf3p.

    Directory of Open Access Journals (Sweden)

    Marc Chatenay-Lapointe

    Full Text Available Synthesis and assembly of the mitochondrial oxidative phosphorylation (OXPHOS system requires genes located both in the nuclear and mitochondrial genomes, but how gene expression is coordinated between these two compartments is not fully understood. One level of control is through regulated expression mitochondrial ribosomal proteins and other factors required for mitochondrial translation and OXPHOS assembly, which are all products of nuclear genes that are subsequently imported into mitochondria. Interestingly, this cadre of genes in budding yeast has in common a 3'-UTR element that is bound by the Pumilio family protein, Puf3p, and is coordinately regulated under many conditions, including during the yeast metabolic cycle. Multiple functions have been assigned to Puf3p, including promoting mRNA degradation, localizing nucleus-encoded mitochondrial transcripts to the outer mitochondrial membrane, and facilitating mitochondria-cytoskeletal interactions and motility. Here we show that Puf3p has a general repressive effect on mitochondrial OXPHOS abundance, translation, and respiration that does not involve changes in overall mitochondrial biogenesis and largely independent of TORC1-mitochondrial signaling. We also identified the cytoplasmic translation factor Slf1p as yeast metabolic cycle-regulated gene that is repressed by Puf3p at the post-transcriptional level and promotes respiration and extension of yeast chronological life span when over-expressed. Altogether, these results should facilitate future studies on which of the many functions of Puf3p is most relevant for regulating mitochondrial gene expression and the role of nuclear-mitochondrial communication in aging and longevity.

  16. 42 CFR 84.134 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.134... Respirators § 84.134 Respirator containers; minimum requirements. Supplied-air respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  17. 42 CFR 84.197 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.197... Cartridge Respirators § 84.197 Respirator containers; minimum requirements. Respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  18. 42 CFR 84.174 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.174... Air-Purifying Particulate Respirators § 84.174 Respirator containers; minimum requirements. (a) Except..., durable container bearing markings which show the applicant's name, the type of respirator it contains...

  19. Regulation of pyruvate oxidation in blowfly flight muscle mitochondria: requirement for ADP.

    Science.gov (United States)

    Bulos, B A; Thomas, B J; Shukla, S P; Sacktor, B

    1984-11-01

    Blowfly (Phormia regina) flight muscle mitochondria oxidized pyruvate ( + proline) in the presence of either ADP (coupled respiration) or carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP-uncoupled respiration). There was an absolute requirement for ADP (Km = 8.0 microM) when pyruvate oxidation was stimulated by FCCP in the presence of oligomycin. This requirement for ADP was limited to the oxidation of pyruvate; uncoupled alpha-glycerolphosphate oxidation proceeded maximally even in the absence of added ADP. Atractylate inhibited uncoupled pyruvate oxidation whether added before (greater than 99%) or after (95%) initiation of respiration with FCCP. In the presence of FCCP, oligomycin, and limiting concentrations of ADP (less than 110 microM), there was a shutoff in the uptake of oxygen. This inhibition of respiration was completely reversed by the addition of more ADP. Plots of net oxygen uptake as a function of the limiting ADP concentration were linear; the observed ADP/O ratio was 0.22 +/- 0.025. An ADP/O ratio of 0.2 was predicted if phosphorylation occurred only at the succinyl-CoA synthetase step of the tricarboxylate cycle. Experiments performed in the presence of limiting concentrations of ADP, and designed to monitor changes in the mitochondrial content of ADP and ATP, demonstrated that the shutoff in oxygen uptake was not due to the presence of a high intramitochondrial concentration of ATP. Indeed, ATP, added to the medium prior to the addition of FCCP, inhibited uncoupled pyruvate oxidation; the apparent KI was 0.8 mM. These results are consistent with the hypothesis that it is the intramitochondrial ATP/ADP ratio that is one of the controlling factors in determining the rate of flux through the tricarboxylate cycle. Changes in the mitochondrial content of citrate, isocitrate, alpha-ketoglutarate, and malate during uncoupled pyruvate oxidation in the presence of a limiting concentration of ADP were consistent with the hypothesis that the

  20. Respiration of Nitrate and Nitrite.

    Science.gov (United States)

    Cole, Jeffrey A; Richardson, David J

    2008-09-01

    Nitrate reduction to ammonia via nitrite occurs widely as an anabolic process through which bacteria, archaea, and plants can assimilate nitrate into cellular biomass. Escherichia coli and related enteric bacteria can couple the eight-electron reduction of nitrate to ammonium to growth by coupling the nitrate and nitrite reductases involved to energy-conserving respiratory electron transport systems. In global terms, the respiratory reduction of nitrate to ammonium dominates nitrate and nitrite reduction in many electron-rich environments such as anoxic marine sediments and sulfide-rich thermal vents, the human gastrointestinal tract, and the bodies of warm-blooded animals. This review reviews the regulation and enzymology of this process in E. coli and, where relevant detail is available, also in Salmonella and draws comparisons with and implications for the process in other bacteria where it is pertinent to do so. Fatty acids may be present in high levels in many of the natural environments of E. coli and Salmonella in which oxygen is limited but nitrate is available to support respiration. In E. coli, nitrate reduction in the periplasm involves the products of two seven-gene operons, napFDAGHBC, encoding the periplasmic nitrate reductase, and nrfABCDEFG, encoding the periplasmic nitrite reductase. No bacterium has yet been shown to couple a periplasmic nitrate reductase solely to the cytoplasmic nitrite reductase NirB. The cytoplasmic pathway for nitrate reduction to ammonia is restricted almost exclusively to a few groups of facultative anaerobic bacteria that encounter high concentrations of environmental nitrate.

  1. β-Glucan from Lentinus edodes inhibits nitric oxide and tumor necrosis factor-α production and phosphorylation of mitogen-activated protein kinases in lipopolysaccharide-stimulated murine RAW 264.7 macrophages.

    Science.gov (United States)

    Xu, Xiaojuan; Yasuda, Michiko; Nakamura-Tsuruta, Sachiko; Mizuno, Masashi; Ashida, Hitoshi

    2012-01-06

    Lentinan (LNT), a β-glucan from the fruiting bodies of Lentinus edodes, is well known to have immunomodulatory activity. NO and TNF-α are associated with many inflammatory diseases. In this study, we investigated the effects of LNT extracted by sonication (LNT-S) on the NO and TNF-α production in LPS-stimulated murine RAW 264.7 macrophages. The results suggested that treatment with LNT-S not only resulted in the striking inhibition of TNF-α and NO production in LPS-activated macrophage RAW 264.7 cells, but also the protein expression of inducible NOS (iNOS) and the gene expression of iNOS mRNA and TNF-α mRNA. It is surprising that LNT-S enhanced LPS-induced NF-κB p65 nuclear translocation and NF-κB luciferase activity, but severely inhibited the phosphorylation of JNK1/2 and ERK1/2. The neutralizing antibodies of anti-Dectin-1 and anti-TLR2 hardly affected the inhibition of NO production. All of these results suggested that the suppression of LPS-induced NO and TNF-α production was at least partially attributable to the inhibition of JNK1/2 and ERK1/2 activation. This work discovered a promising molecule to control the diseases associated with overproduction of NO and TNF-α.

  2. Phosphorylation regulates SIRT1 function.

    Directory of Open Access Journals (Sweden)

    Tsutomu Sasaki

    Full Text Available BACKGROUND: SIR2 is an NAD(+-dependent deacetylase [1]-[3] implicated in the regulation of lifespan in species as diverse as yeast [4], worms [5], and flies [6]. We previously reported that the level of SIRT1, the mammalian homologue of SIR2 [7], [8], is coupled to the level of mitotic activity in cells both in vitro and in vivo[9]. Cells from long-lived mice maintained SIRT1 levels of young mice in tissues that undergo continuous cell replacement by proliferating stem cells. Changes in SIRT1 protein level were not associated with changes in mRNA level, suggesting that SIRT1 could be regulated post-transcriptionally. However, other than a recent report on sumoylation [10] and identification of SIRT1 as a nuclear phospho-protein by mass spectrometry [11], post-translational modifications of this important protein have not been reported. METHODOLOGY/PRINCIPAL FINDINGS: We identified 13 residues in SIRT1 that are phosphorylated in vivo using mass spectrometry. Dephosphorylation by phosphatases in vitro resulted in decreased NAD(+-dependent deacetylase activity. We identified cyclinB/Cdk1 as a cell cycle-dependent kinase that forms a complex with and phosphorylates SIRT1. Mutation of two residues phosphorylated by Cyclin B/Cdk1 (threonine 530 and serine 540 disturbs normal cell cycle progression and fails to rescue proliferation defects in SIRT1-deficient cells [12], [13]. CONCLUSIONS/SIGNIFICANCE: Pharmacological manipulation of SIRT1 activity is currently being tested as a means of extending lifespan in mammals. Treatment of obese mice with resveratrol, a pharmacological activator of SIRT1, modestly but significantly improved longevity and, perhaps more importantly, offered some protection against the development of type 2 diabetes mellitus and metabolic syndrome [14]-[16]. Understanding the endogenous mechanisms that regulate the level and activity of SIRT1, therefore, has obvious relevance to human health and disease. Our results identify

  3. Soil Respiration And Respiration Partitioning In An Oak-Savannah With A History Of Fertilization

    Science.gov (United States)

    Morris, K. A.; Nair, R.; Schrumpf, M.; Migliavacca, M.

    2017-12-01

    Soil respiration is a combination of autotrophic and heterotrophic components. These components have different controls and structurally complex ecosystems such as oak-savannahs offer an opportunity to study strongly contrasting conditions (ie., soil from under trees versus open areas) in an environment with similar soil mineralogy and climatic patterns. To measure respiration coming from plant roots, fungal hyphae, and free-living microbes we established stations of soil cores comprised of three selectively permeable meshes under tree canopies and in open grassy areas of a Holm Oak (Quercus ilex) savannah in Extremadura, Spain. Large plots of this ecosystem had previously been fertilized as part of a stoichiometeric imbalance study (in 2015). Stations were installed in Dec. 2016 within four plots; control, N added, P added, and N+P added. Respiration from cores was measured in campaigns at key phenological stages with a portable Li-Cor 8100A unit. Six months after installation > 50% of soil respiration was attributable to free-living microbes. There is a persistent effect of the prior fertilization, resulting in increased soil respiration in open areas regardless of fertilizer type, while respiration from under tree canopies had a varied response. Soil under tree canopies showed distinct sensitivity to stoichiometric imbalance, meaning that addition of N or P alone either did not change respiration or decreased it slightly, while N+P stimulated respiration. We determined that respiration from free-living microbes is a major component of soil respiration even in the most active plant growing season. However, because of the lag between the time of fertilization and the time of measurement, it not possible to say whether treatment responses are due solely to nutrient status of the soil or whether changes in plant biomass and species composition also play a role. Additional work planned at the site will shed light on this uncertainty as well as the contribution of

  4. [Research progress on photosynthesis regulating and controlling soil respiration].

    Science.gov (United States)

    Jing, Yan-Li; Guan, De-Xin; Wu, Jia-Bing; Wang, An-Zhi; Yuan, Feng-Hui

    2013-01-01

    To understand the mechanisms of soil respiration and accurately estimate its magnitude are the crucial basis of evaluating global carbon balance. However, the previously built soil respiration forecast models usually neglect the physiological processes that photosynthesis supplies substrates for rhizospheric respiration, leading to the defect in evaluating the mechanisms of soil respiration. This paper summarized the research progress on the mechanisms of photosynthetic regulation and control of soil respiration, introduced the related main research methods, and discussed the existing problems and research hotspots.

  5. Phosphorylated nano-diamond/ Polyimide Nanocomposites

    International Nuclear Information System (INIS)

    Beyler-Çiǧil, Asli; Çakmakçi, Emrah; Kahraman, Memet Vezir

    2014-01-01

    In this study, a novel route to synthesize polyimide (PI)/phosphorylated nanodiamond films with improved thermal and mechanical properties was developed. Surface phosphorylation of nano-diamond was performed in dichloromethane. Phosphorylation dramatically enhanced the thermal stability of nano-diamond. Poly(amic acid) (PAA), which is the precursor of PI, was successfully synthesized with 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-oxydianiline (4,4'-ODA) in the solution of N,N- dimethylformamide (DMF). Pure BTDA-ODA polyimide films and phosphorylated nanodiamond containing BTDA-ODA PI films were prepared. The PAA displayed good compatibility with phosphorylated nano-diamond. The morphology of the polyimide (PI)/phosphorylated nano-diamond was characterized by scanning electron microscopy (SEM). Chemical structure of polyimide and polyimide (PI)/phosphorylated nano-diamond was characterized by FTIR. SEM and FTIR results showed that the phosphorylated nano-diamond was successfully prepared. Thermal properties of the polyimide (PI)/phosphorylated nanodiamond was characterized by thermogravimetric analysis (TGA). TGA results showed that the thermal stability of (PI)/phosphorylated nano-diamond film was increased

  6. Phosphorylation of Cytochrome c Threonine 28 Regulates Electron Transport Chain Activity in Kidney: IMPLICATIONS FOR AMP KINASE.

    Science.gov (United States)

    Mahapatra, Gargi; Varughese, Ashwathy; Ji, Qinqin; Lee, Icksoo; Liu, Jenney; Vaishnav, Asmita; Sinkler, Christopher; Kapralov, Alexandr A; Moraes, Carlos T; Sanderson, Thomas H; Stemmler, Timothy L; Grossman, Lawrence I; Kagan, Valerian E; Brunzelle, Joseph S; Salomon, Arthur R; Edwards, Brian F P; Hüttemann, Maik

    2017-01-06

    Mammalian cytochrome c (Cytc) plays a key role in cellular life and death decisions, functioning as an electron carrier in the electron transport chain and as a trigger of apoptosis when released from the mitochondria. However, its regulation is not well understood. We show that the major fraction of Cytc isolated from kidneys is phosphorylated on Thr 28 , leading to a partial inhibition of respiration in the reaction with cytochrome c oxidase. To further study the effect of Cytc phosphorylation in vitro, we generated T28E phosphomimetic Cytc, revealing superior behavior regarding protein stability and its ability to degrade reactive oxygen species compared with wild-type unphosphorylated Cytc Introduction of T28E phosphomimetic Cytc into Cytc knock-out cells shows that intact cell respiration, mitochondrial membrane potential (ΔΨ m ), and ROS levels are reduced compared with wild type. As we show by high resolution crystallography of wild-type and T28E Cytc in combination with molecular dynamics simulations, Thr 28 is located at a central position near the heme crevice, the most flexible epitope of the protein apart from the N and C termini. Finally, in silico prediction and our experimental data suggest that AMP kinase, which phosphorylates Cytc on Thr 28 in vitro and colocalizes with Cytc to the mitochondrial intermembrane space in the kidney, is the most likely candidate to phosphorylate Thr 28 in vivo We conclude that Cytc phosphorylation is mediated in a tissue-specific manner and leads to regulation of electron transport chain flux via "controlled respiration," preventing ΔΨ m hyperpolarization, a known cause of ROS and trigger of apoptosis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Phosphorylation of Cytochrome c Threonine 28 Regulates Electron Transport Chain Activity in Kidney: IMPLICATIONS FOR AMP KINASE

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, Gargi; Varughese, Ashwathy; Ji, Qinqin; Lee, Icksoo; Liu, Jenney; Vaishnav, Asmita; Sinkler, Christopher; Kapralov, Alexandr A.; Moraes, Carlos T.; Sanderson, Thomas H.; Stemmler, Timothy L.; Grossman, Lawrence I.; Kagan, Valerian E.; Brunzelle, Joseph S.; Salomon, Arthur R.; Edwards, Brian F. P.; Hüttemann, Maik

    2016-10-07

    Mammalian cytochrome c (Cytc) plays a key role in cellular life and death decisions, functioning as an electron carrier in the electron transport chain and as a trigger of apoptosis when released from the mitochondria. However, its regulation is not well understood. We show that the major fraction of Cytc isolated from kidneys is phosphorylated on Thr28, leading to a partial inhibition of respiration in the reaction with cytochrome c oxidase. To further study the effect of Cytc phosphorylation in vitro, we generated T28E phosphomimetic Cytc, revealing superior behavior regarding protein stability and its ability to degrade reactive oxygen species compared with wild-type unphosphorylated Cytc. Introduction of T28E phosphomimetic Cytc into Cytc knock-out cells shows that intact cell respiration, mitochondrial membrane potential (ΔΨm), and ROS levels are reduced compared with wild type. As we show by high resolution crystallography of wild-type and T28E Cytc in combination with molecular dynamics simulations, Thr28 is located at a central position near the heme crevice, the most flexible epitope of the protein apart from the N and C termini. Finally, in silico prediction and our experimental data suggest that AMP kinase, which phosphorylates Cytc on Thr28 in vitro and colocalizes with Cytc to the mitochondrial intermembrane space in the kidney, is the most likely candidate to phosphorylate Thr28 in vivo. We conclude that Cytc phosphorylation is mediated in a tissue-specific manner and leads to regulation of electron transport chain flux via “controlled respiration,” preventing ΔΨm hyperpolarization, a known cause of ROS and trigger of apoptosis.

  8. Plant Respiration and Climate Change Effects

    International Nuclear Information System (INIS)

    Bruhn, D.

    2002-04-01

    Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO 2 on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO 2 from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO 2 on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO 2 . These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO 2 . The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO 2 exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO 2 release. (au)

  9. Plant Respiration and Climate Change Effects

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, D

    2002-04-01

    Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO{sub 2} on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO{sub 2} from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO{sub 2} on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO{sub 2}. These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO{sub 2}. The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO{sub 2} exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO{sub 2} release. (au)

  10. Tyrosine phosphorylation in signal transduction

    International Nuclear Information System (INIS)

    Roberts, T.M.; Kaplan, D.; Morgan, W.; Keller, T.; Mamon, H.; Piwnica-Worms, H.; Druker, B.; Whitman, M.; Morrison, D.; Cohen, B.; Schaffhausen, B.; Cantley, L.; Rapp, U.

    1988-01-01

    Recent work has focused on the elucidation of the mechanisms by which membrane-bound tyrosine kinases transmit signals within the cell. To examine the role of tyrosine phosphorylation the authors have employed the following strategy. First, they have utilized antibodies to phosphotyrosine (anti-P.Tyr) to identify candidate substrates of various tyrosine kinases, such as pp60 c-src , the CSF- receptor, or the platelet-derived growth factor (PDGF) receptor. Second, they have attempted to characterize the biochemical properties of the putative substrates and to determine in what manner these properties are modified by phosphorylation on tyrosine residues. In this endeavor, they are recapitulating the classic biochemical analysis used to study the effect of kinases on metabolism. The final portion of our work consists of using modern molecular biological strategies to clone the genes or cDNAs for the substrates and overproduce the relevant proteins for studies in vitro in defined systems. This paper describes the first and second aspects of this strategy, the identification and characterization of novel substrate molecules

  11. Conformational Clusters of Phosphorylated Tyrosine.

    Science.gov (United States)

    Abdelrasoul, Maha; Ponniah, Komala; Mao, Alice; Warden, Meghan S; Elhefnawy, Wessam; Li, Yaohang; Pascal, Steven M

    2017-12-06

    Tyrosine phosphorylation plays an important role in many cellular and intercellular processes including signal transduction, subcellular localization, and regulation of enzymatic activity. In 1999, Blom et al., using the limited number of protein data bank (PDB) structures available at that time, reported that the side chain structures of phosphorylated tyrosine (pY) are partitioned into two conserved conformational clusters ( Blom, N.; Gammeltoft, S.; Brunak, S. J. Mol. Biol. 1999 , 294 , 1351 - 1362 ). We have used the spectral clustering algorithm to cluster the increasingly growing number of protein structures with pY sites, and have found that the pY residues cluster into three distinct side chain conformations. Two of these pY conformational clusters associate strongly with a narrow range of tyrosine backbone conformation. The novel cluster also highly correlates with the identity of the n + 1 residue, and is strongly associated with a sequential pYpY conformation which places two adjacent pY side chains in a specific relative orientation. Further analysis shows that the three pY clusters are associated with distinct distributions of cognate protein kinases.

  12. Threonine phosphorylation of rat liver glycogen synthase

    International Nuclear Information System (INIS)

    Arino, J.; Arro, M.; Guinovart, J.J.

    1985-01-01

    32 P-labeled glycogen synthase specifically immunoprecipitated from 32 P-phosphate incubated rat hepatocytes contains, in addition to [ 32 P] phosphoserine, significant levels of [ 32 P] phosphothreonine. When the 32 P-immunoprecipitate was cleaved with CNBr, the [ 32 P] phosphothreonine was recovered in the large CNBr fragment (CB-2, Mapp 28 Kd). Homogeneous rat liver glycogen synthase was phosphorylated by all the protein kinases able to phosphorylate CB-2 in vitro. After analysis of the immunoprecipitated enzyme for phosphoaminoacids, it was observed that only casein kinase II was able to phosphorylate on threonine and 32 P-phosphate was only found in CB-2. These results demonstrate that rat liver glycogen synthase is phosphorylated at threonine site(s) contained in CB-2 and strongly indicate that casein kinase II may play a role in the ''in vivo'' phosphorylation of liver glycogen synthase. This is the first protein kinase reported to phosphorylate threonine residues in liver glycogen synthase

  13. Identification of ATM Protein Kinase Phosphorylation Sites by Mass Spectrometry.

    Science.gov (United States)

    Graham, Mark E; Lavin, Martin F; Kozlov, Sergei V

    2017-01-01

    ATM (ataxia-telangiectasia mutated) protein kinase is a key regulator of cellular responses to DNA damage and oxidative stress. DNA damage triggers complex cascade of signaling events leading to numerous posttranslational modification on multitude of proteins. Understanding the regulation of ATM kinase is therefore critical not only for understanding the human genetic disorder ataxia-telangiectasia and potential treatment strategies, but essential for deciphering physiological responses of cells to stress. These responses play an important role in carcinogenesis, neurodegeneration, and aging. We focus here on the identification of DNA damage inducible ATM phosphorylation sites to understand the importance of autophosphorylation in the mechanism of ATM kinase activation. We demonstrate the utility of using immunoprecipitated ATM in quantitative LC-MS/MS workflow with stable isotope dimethyl labeling of ATM peptides for identification of phosphorylation sites.

  14. Autophagy Deficiency Compromises Alternative Pathways of Respiration following Energy Deprivation in Arabidopsis thaliana.

    Science.gov (United States)

    Barros, Jessica A S; Cavalcanti, João Henrique F; Medeiros, David B; Nunes-Nesi, Adriano; Avin-Wittenberg, Tamar; Fernie, Alisdair R; Araújo, Wagner L

    2017-09-01

    Under heterotrophic conditions, carbohydrate oxidation inside the mitochondrion is the primary energy source for cellular metabolism. However, during energy-limited conditions, alternative substrates are required to support respiration. Amino acid oxidation in plant cells plays a key role in this by generating electrons that can be transferred to the mitochondrial electron transport chain via the electron transfer flavoprotein/ubiquinone oxidoreductase system. Autophagy, a catabolic mechanism for macromolecule and protein recycling, allows the maintenance of amino acid pools and nutrient remobilization. Although the association between autophagy and alternative respiratory substrates has been suggested, the extent to which autophagy and primary metabolism interact to support plant respiration remains unclear. To investigate the metabolic importance of autophagy during development and under extended darkness, Arabidopsis ( Arabidopsis thaliana ) mutants with disruption of autophagy ( atg mutants) were used. Under normal growth conditions, atg mutants showed lower growth and seed production with no impact on photosynthesis. Following extended darkness, atg mutants were characterized by signatures of early senescence, including decreased chlorophyll content and maximum photochemical efficiency of photosystem II coupled with increases in dark respiration. Transcript levels of genes involved in alternative pathways of respiration and amino acid catabolism were up-regulated in atg mutants. The metabolite profiles of dark-treated leaves revealed an extensive metabolic reprogramming in which increases in amino acid levels were partially compromised in atg mutants. Although an enhanced respiration in atg mutants was observed during extended darkness, autophagy deficiency compromises protein degradation and the generation of amino acids used as alternative substrates to the respiration. © 2017 American Society of Plant Biologists. All Rights Reserved.

  15. Improving respiration measurements with gas exchange analyzers.

    Science.gov (United States)

    Montero, R; Ribas-Carbó, M; Del Saz, N F; El Aou-Ouad, H; Berry, J A; Flexas, J; Bota, J

    2016-12-01

    Dark respiration measurements with open-flow gas exchange analyzers are often questioned for their low accuracy as their low values often reach the precision limit of the instrument. Respiration was measured in five species, two hypostomatous (Vitis Vinifera L. and Acanthus mollis) and three amphistomatous, one with similar amount of stomata in both sides (Eucalyptus citriodora) and two with different stomata density (Brassica oleracea and Vicia faba). CO 2 differential (ΔCO 2 ) increased two-fold with no change in apparent R d , when the two leaves with higher stomatal density faced outside. These results showed a clear effect of the position of stomata on ΔCO 2 . Therefore, it can be concluded that leaf position is important to guarantee the improvement of respiration measurements increasing ΔCO 2 without affecting the respiration results by leaf or mass units. This method will help to increase the accuracy of leaf respiration measurements using gas exchange analyzers. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. Simplified pressure method for respirator fit testing.

    Science.gov (United States)

    Han, D; Xu, M; Foo, S; Pilacinski, W; Willeke, K

    1991-08-01

    A simplified pressure method has been developed for fit testing air-purifying respirators. In this method, the air-purifying cartridges are replaced by a pressure-sensing attachment and a valve. While wearers hold their breath, a small pump extracts air from the respirator cavity until a steady-state pressure is reached in 1 to 2 sec. The flow rate through the face seal leak is a unique function of this pressure, which is determined once for all respirators, regardless of the respirator's cavity volume or deformation because of pliability. The contaminant concentration inside the respirator depends on the degree of dilution by the flow through the cartridges. The cartridge flow varies among different brands and is measured once for each brand. The ratio of cartridge to leakflow is a measure of fit. This flow ratio has been measured on human subjects and has been compared to fit factors determined on the same subjects by means of photometric and particle count tests. The aerosol tests gave higher values of fit.

  17. The real limits to marine life: a further critique of the Respiration Index

    Science.gov (United States)

    Seibel, B. A.; Childress, J. J.

    2013-05-01

    The recently proposed "Respiration Index" (RI = log PO2/PCO2) suggests that aerobic metabolism is limited by the ratio of reactants (oxygen) to products (carbon dioxide) according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = -686 kcal mol-1), carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503), where ΔG = 0. Thus, a Respiration Index of -503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

  18. The real limits to marine life: a further critique of the Respiration Index

    Directory of Open Access Journals (Sweden)

    B. A. Seibel

    2013-05-01

    Full Text Available The recently proposed "Respiration Index" (RI = log PO2/PCO2 suggests that aerobic metabolism is limited by the ratio of reactants (oxygen to products (carbon dioxide according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = −686 kcal mol−1, carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503, where ΔG = 0. Thus, a Respiration Index of −503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

  19. Anaerobic respiration of Escherichia coli in the mouse intestine.

    Science.gov (United States)

    Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

    2011-10-01

    The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

  20. Mapping of p140Cap phosphorylation sites

    DEFF Research Database (Denmark)

    Repetto, Daniele; Aramu, Simona; Boeri Erba, Elisabetta

    2013-01-01

    phosphorylation and tunes its interactions with other regulatory molecules via post-translation modification. In this work, using mass spectrometry, we found that p140Cap is in vivo phosphorylated on tyrosine (Y) within the peptide GEGLpYADPYGLLHEGR (from now on referred to as EGLYA) as well as on three serine...... residues. Consistently, EGLYA has the highest score of in silico prediction of p140Cap phosphorylation. To further investigate the p140Cap function, we performed site specific mutagenesis on tyrosines inserted in EGLYA and EPLYA, a second sequence with the same highest score of phosphorylation. The mutant...

  1. Phosphorylation of human link proteins

    International Nuclear Information System (INIS)

    Oester, D.A.; Caterson, B.; Schwartz, E.R.

    1986-01-01

    Three link proteins of 48, 44 and 40 kDa were purified from human articular cartilage and identified with monoclonal anti-link protein antibody 8-A-4. Two sets of lower molecular weight proteins of 30-31 kDa and 24-26 kDa also contained link protein epitopes recognized by the monoclonal antibody and were most likely degradative products of the intact link proteins. The link proteins of 48 and 40 kDa were identified as phosphoproteins while the 44 kDa link protein did not contain 32 P. The phosphorylated 48 and 40 kDa link proteins contained approximately 2 moles PO 4 /mole link protein

  2. SIMAC - A phosphoproteomic strategy for the rapid separation of mono-phosphorylated from multiply phosphorylated peptides

    DEFF Research Database (Denmark)

    Thingholm, Tine E; Jensen, Ole N; Robinson, Phillip J

    2008-01-01

    spectrometric analysis, such as immobilized metal affinity chromatography or titanium dioxide the coverage of the phosphoproteome of a given sample is limited. Here we report a simple and rapid strategy - SIMAC - for sequential separation of mono-phosphorylated peptides and multiply phosphorylated peptides from...... and an optimized titanium dioxide chromatographic method. More than double the total number of identified phosphorylation sites was obtained with SIMAC, primarily from a three-fold increase in recovery of multiply phosphorylated peptides....

  3. Molecular underpinnings of nitrite effect on CymA-dependent respiration in Shewanella oneidensis

    Directory of Open Access Journals (Sweden)

    Miao Jin

    2016-07-01

    Full Text Available Shewanella exhibit a remarkable versatility of respiration, with a diverse array of electron acceptors (EAs. In environments where these bacteria thrive, multiple EAs are usually present. However, we know little about strategies by which these EAs and their interaction affect ecophysiology of Shewanella. In this study, we demonstrate in the model strain, Shewanella oneidensis MR-1, that nitrite, not through nitric oxide to which it may convert, inhibits respiration of fumarate, and probably many other EAs whose reduction depends on quinol dehydrogenase CymA. This is achieved via the repression of cyclic adenosine monophosphate (cAMP production, a second messenger required for activation of cAMP-receptor protein (Crp which plays a primary role in regulation of respiration. If nitrite is not promptly removed, intracellular cAMP levels drop, and this impairs Crp activity. As a result, the production of nitrite reductase NrfA, CymA, and fumarate reductase FccA is substantially reduced. In contrast, nitrite can be simultaneously respired with trimethylamine N-oxide, resulting in enhanced biomass.

  4. Dietary α-lactalbumin induced fatty liver by enhancing nuclear liver X receptor αβ/sterol regulatory element-binding protein-1c/PPARγ expression and minimising PPARα/carnitine palmitoyltransferase-1 expression and AMP-activated protein kinase α phosphorylation associated with atherogenic dyslipidaemia, insulin resistance and oxidative stress in Balb/c mice.

    Science.gov (United States)

    López-Oliva, María Elvira; Garcimartin, Alba; Muñoz-Martínez, Emilia

    2017-12-01

    The effect and the role played by dietary α-lactalbumin (α-LAC) on hepatic fat metabolism are yet to be fully elucidated. We reported previously that α-LAC intake induced atherogenic dyslipidaemia in Balb/c mice. The aim of the present study was to investigate if this atherogenic effect could be due to a possible α-LAC-induced hepatic steatosis. We examine the ability of dietary α-LAC to induce liver steatosis, identifying the molecular mechanisms underlying hepatic lipid metabolism in association with the lipid profile, peripheral insulin resistance (IR) and changes in the hepatic oxidative environment. Male Balb/c mice (n 6) were fed with diets containing either chow or 14 % α-LAC for 4 weeks. The α-LAC-fed mice developed abdominal adiposity and IR. Moderate liver steatosis with increased TAG and NEFA contents was correlated with atherogenic dyslipidaemia. There was increased nuclear expression of liver X receptor αβ (LXRαβ), sterol regulatory element-binding protein-1c (SREBP-1c) and PPARγ transcription factors and of the cytosolic enzymes acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase involved in the hepatic de novo lipogenesis. The opposite was found for the nuclear receptor PPARα and the mitochondrial enzyme carnitine palmitoyltransferase-1 (CPT-1), leading to reduced fatty acid β-oxidation (FAO). These changes were associated with a significant decrease in both p-Thr172-AMP-activated protein kinase α (AMPKα) (inactivation) and p-Ser79-ACC1 (activation) and with a more oxidative liver environment increasing lipid peroxidation and protein oxidation and reducing GSH:GSSG ratio in the α-LAC-fed mice. In conclusion, 4 weeks of 14 % α-LAC feeding induced liver steatosis associated with atherogenic dyslipidaemia, IR and oxidative stress by enhancing nuclear LXRαβ/SREBP-1c/PPARγ expression and diminishing PPARα/CPT-1 expression and AMPKα phosphorylation shifting the hepatic FAO toward fatty acid synthesis in Balb/c mice.

  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. Estimating Canopy Dark Respiration for Crop Models

    Science.gov (United States)

    Monje Mejia, Oscar Alberto

    2014-01-01

    Crop production is obtained from accurate estimates of daily carbon gain.Canopy gross photosynthesis (Pgross) can be estimated from biochemical models of photosynthesis using sun and shaded leaf portions and the amount of intercepted photosyntheticallyactive radiation (PAR).In turn, canopy daily net carbon gain can be estimated from canopy daily gross photosynthesis when canopy dark respiration (Rd) is known.

  7. LIMITATION OF SOIL RESPIRATION DURING DRY PERIOD

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Marian; Janouš, Dalibor; Acosta, Manuel

    2003-01-01

    Roč. 16, - (2003), s. 47-52. ISBN 80-7157-297-7 R&D Projects: GA MŠk LN00A141; GA AV ČR IBS6087005 Institutional research plan: CEZ:AV0Z6087904 Keywords : moisture * Norway spruce * precipitation * respiration * soil CO2 efflux Subject RIV: EH - Ecology, Behaviour

  8. Internal current generation in respiration chambers

    Science.gov (United States)

    Saborowski, R.; Buchholz, F.

    1998-06-01

    A technical device generating a constant and directed current within a sealed respiration chamber is described. It does not involve any external pumps or tubing. This system is easy to handle, and improved the maintenance of rheotactic pelagic species like the Northern krill ( Meganyctiphanes norvegica, Crustacea) or small fishes ( Gasterosteus aculeatus) under experimental conditions.

  9. 42 CFR 84.1130 - Respirators; description.

    Science.gov (United States)

    2010-10-01

    ...; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84...., dust clouds produced in mining, quarrying, and tunneling, and in dusts produced during industrial... respective vapors, or from the chemical reaction between their respective vapors and gases. (3) Air-purifying...

  10. Development of conformal respirator monitoring technology

    International Nuclear Information System (INIS)

    Shonka, J.J.; Weismann, J.J.; Logan, R.J.

    1997-04-01

    This report summarizes the results of a Small Business Innovative Research Phase II project to develop a modular, surface conforming respirator monitor to improve upon the manual survey techniques presently used by the nuclear industry. Research was performed with plastic scintillator and gas proportional modules in an effort to find the most conducive geometry for a surface conformal, position sensitive monitor. The respirator monitor prototype developed is a computer controlled, position-sensitive detection system employing 56 modular proportional counters mounted in molds conforming to the inner and outer surfaces of a commonly used respirator (Scott Model 801450-40). The molds are housed in separate enclosures and hinged to create a open-quotes waffle-ironclose quotes effect so that the closed monitor will simultaneously survey both surfaces of the respirator. The proportional counter prototype was also designed to incorporate Shonka Research Associates previously developed charge-division electronics. This research provided valuable experience into pixellated position sensitive detection systems. The technology developed can be adapted to other monitoring applications where there is a need for deployment of many traditional radiation detectors

  11. Geochemical importance of isotopic fractionation during respiration

    International Nuclear Information System (INIS)

    Schleser, G.; Foerstel, H.

    1975-01-01

    In 1935 it was found that atmospheric oxygen contained a relatively greater abundance of the 18 O isotope than did the oxygen bound in water (Dole effect). A major contribution to the fractionation of the stable oxygen isotopes should result from the respiration of microorganisms. In this respect our interest centers on the soil because nearly all organic material produced on land is decomposed within the soil. The oceans are less important because the primary productivity on land is twice the value for the oceans. In a first approach we measured the oxygen isotope fractionation during the respiration of E. coli K12 for different respiration rates. These results, accomplished with a chemostat, indicate that the fractionation factor α of the oxygen isotopes increases with the increasing respiratory activity, measured as Q/sub O 2 /. At low dilution rates or growth rates respectively of about 0.05 h -1 , the fractionation factor amounts to 1.006 increasing to 1.017 at dilution rates of about 1.0 h -1 . The results are interpreted as a kinetic mass fractionation due to the slightly different diffusion coefficients of 16 O 2 and 18 O 16 O. The respiration rates in conjunction with the corresponding fractionation data are compared with the respiration rates of typical soil microorganisms such as Azotobacter, in order to deduce fractionation data for these organisms. This is necessary to calculate a mean global fractionation factor. Understanding the Dole effect with these fractionation processes should finally give us the opportunity to calculate gas-exchange rates between the atmosphere and the oceans, on the basis of the behavior of the stable oxygen isotopes

  12. Acceptable respiratory protection program and LASL respirator research

    International Nuclear Information System (INIS)

    Skaggs, B.J.

    1979-01-01

    A short history is presented on the LASL Respiratory Protection Training Programs. Then a discussion is given on the major points of an acceptable respiratory protection program utilizing the points required by the Occupational, Safety, and Health Administration (OSHA) Regulation 29 CFR 1910.134. Contributions to respirator research are reviewed. Discussion is presented under the following section headings: program administration; respirator selection; respirator use; fitting and training; respirator maintenance; medical clearance and surveillance; special problems; program evaluation; and documentation

  13. Contribution of root to soil respiration and carbon balance in ...

    Indian Academy of Sciences (India)

    Soil respiration varied from 2.5 to 11.9 g CO2 m-2 d-1 and from 1.5 to 9.3 g CO2 m-2 d-1, and the contribution of root respiration to total soil respiration from 38% to 76% and from 25% to 72% in Communities 1 and 2, respectively. During the growing season (May–September), soil respiration, shoot biomass, live root ...

  14. Characterization of the respiration-induced yeast mitochondrial permeability transition pore.

    Science.gov (United States)

    Bradshaw, Patrick C; Pfeiffer, Douglas R

    2013-12-01

    When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane, dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable through the yPTP in an industrial yeast strain, Yeast Foam. The presence of oligomycin, an inhibitor of ATP synthase, allowed for respiration-induced mannitol permeability in mitochondria from this strain. Potassium (K+) had varied effects on the respiration-induced yPTP, depending on the concentration of the respiratory substrate added. At low respiratory substrate concentrations K+ inhibited respiration-induced yPTP opening, while at high substrate concentrations this effect diminished. However, at the high respiratory substrate concentrations, the presence of K+ partially prevented phosphate inhibition of yPTP opening. Phosphate was found to inhibit respiration-induced yPTP opening by binding a site on the matrix space side of the inner membrane in addition to its known inhibitory effect of donating protons to the matrix space to prevent the pH change necessary for yPTP opening. The respiration-induced yPTP was also inhibited by NAD, Mg2+, NH4 + or the oxyanion vanadate polymerized to decavanadate. The results demonstrate similar effectors of the respiration-induced yPTP as those previously described for the ATP-induced yPTP and reconcile previous strain-dependent differences in yPTP solute selectivity. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Nutrients and temperature additively increase stream microbial respiration

    Science.gov (United States)

    David W. P. Manning; Amy D. Rosemond; Vladislav Gulis; Jonathan P. Benstead; John S. Kominoski

    2017-01-01

    Rising temperatures and nutrient enrichment are co‐occurring global‐change drivers that stimulate microbial respiration of detrital carbon, but nutrient effects on the temperature dependence of respiration in aquatic ecosystems remain uncertain. We measured respiration rates associated with leaf litter, wood, and fine benthic organic matter (FBOM) across...

  16. Thermal adaptation of heterotrophic soil respiration in laboratory microcosms.

    Science.gov (United States)

    Mark A. Bradford; Brian W. Watts; Christian A. Davies

    2010-01-01

    Respiration of heterotrophic microorganisms decomposing soil organic carbon releases carbon dioxide from soils to the atmosphere. In the short term, soil microbial respiration is strongly dependent on temperature. In the long term, the response of heterotrophic soil respiration to temperature is uncertain. However, following established evolutionary tradeoffs, mass-...

  17. 42 CFR 84.1134 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84... Combination Gas Masks § 84.1134 Respirator containers; minimum requirements. (a) Except as provided in paragraph (b) of this section each respirator shall be equipped with a substantial, durable container...

  18. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic ECG/respirator synchronizer. 892.1970... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator synchronizer. (a) Identification. A radiographic ECG/respirator synchronizer is a device intended to be used to...

  19. What controls respiration rate in stored sugarbeet roots

    Science.gov (United States)

    Although respiration is estimated to be responsible for 60 to 80% of the sucrose lost during storage, the mechanisms by which sugarbeet roots regulate their respiration rate are unknown. In plants, respiration rate is regulated by (1) available respiratory capacity, (2) cellular energy status, (3) ...

  20. Redefinition and global estimation of basal ecosystem respiration rate

    DEFF Research Database (Denmark)

    Yuan, Wenping; Luo, Yiqi; Li, Xianglan

    2011-01-01

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models sti...

  1. Quantifying soil respiration at landscape scales. Chapter 11

    Science.gov (United States)

    John B. Bradford; Michael G. Ryan

    2008-01-01

    Soil CO2, efflux, or soil respiration, represents a substantial component of carbon cycling in terrestrial ecosystems. Consequently, quantifying soil respiration over large areas and long time periods is an increasingly important goal. However, soil respiration rates vary dramatically in space and time in response to both environmental conditions...

  2. Induction by ethylene of cyanide-resistant respiration

    Energy Technology Data Exchange (ETDEWEB)

    Solomos, T.; Laties, G.G.

    1976-05-17

    Ethylene and cyanide induce an increase in respiration in a variety of plant tissues, whereas ethylene has no effect on tissues whose respiration is strongly inhibited by cyanide. It is suggested that the existence of a cyanide-insensitive electron transport path is a prerequisite for stimulation of respiration by ethylene.

  3. Membrane phosphorylation and nerve cell function

    International Nuclear Information System (INIS)

    Baer, P.R.

    1982-01-01

    This thesis deals with the phosphorylation of membrane components. In part I a series of experiments is described using the hippocampal slice as a model system. In part II a different model system - cultured hybrid cells - is used to study protein and lipid phosphorylation, influenced by incubation with neuropeptides. In part III in vivo and in vitro studies are combined to study protein phosphorylation after neuroanatomical lesions. In a section of part II (Page 81-90) labelling experiments of the membrane inositol-phospholipids are described. 32 P-ATP was used to label phospholipids in intact hybrid cells, and short incubations were found to be the most favourable. (C.F.)

  4. Protein-Tyrosine Phosphorylation in Bacillus subtilis

    DEFF Research Database (Denmark)

    Mijakovic, Ivan; Petranovic, Dina; Bottini, N.

    2005-01-01

    phosphorylation, indicating that this post-translational modifi cation could regulate physiological processes ranging from stress response and exopolysaccharide synthesis to DNA metabolism. Some interesting work in this fi eld was done in Bacillus subtilis , and we here present the current state of knowledge...... on protein-tyrosine phosphorylation in this gram-positive model organism. With its two kinases, two kinase modulators, three phosphatases and at least four different tyrosine-phosphorylated substrates, B. subtilis is the bacterium with the highest number of presently known participants in the global network...

  5. A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce-dominated forest

    Science.gov (United States)

    E.A. Davidson; A.D. Richardson; K.E. Savage; D.Y. Hollinger

    2006-01-01

    Annual budgets and fitted temperature response curves for soil respiration and ecosystem respiration provide useful information for partitioning annual carbon budgets of ecosystems, but they may not adequately reveal seasonal variation in the ratios of these two fluxes. Soil respiration (Rs) typically contributes 30-80% of...

  6. Insulin treatment promotes tyrosine phosphorylation of PKR and inhibits polyIC induced PKR threonine phosphorylation.

    Science.gov (United States)

    Swetha, Medchalmi; Ramaiah, Kolluru V A

    2015-11-01

    Tyrosine phosphorylation of insulin receptor beta (IRβ) in insulin treated HepG2 cells is inversely correlated to ser(51) phosphorylation in the alpha-subunit of eukaryotic initiation factor 2 (eIF2α) that regulates protein synthesis. Insulin stimulates interaction between IRβ and PKR, double stranded RNA-dependent protein kinase, also known as EIF2AK2, and phosphorylation of tyrosine residues in PKR, as analyzed by immunoprecipitation and pull down assays using anti-IRβ and anti-phosphotyrosine antibodies, recombinant IRβ and immunopurified PKR. Further polyIC or synthetic double stranded RNA-induced threonine phosphorylation or activation of immunopurified and cellular PKR is suppressed in the presence of insulin treated purified IRβ and cell extracts. Acute, but not chronic, insulin treatment enhances tyrosine phosphorylation of IRβ, its interaction with PKR and tyrosine phosphorylation of PKR. In contrast, lipopolysaccharide that stimulates threonine phosphorylation of PKR and eIF2α phosphorylation and AG 1024, an inhibitor of the tyrosine kinase activity of IRβ, reduces PKR association with the receptor, IRβ in HepG2 cells. These findings therefore may suggest that tyrosine phosphorylated PKR plays a role in the regulation of insulin induced protein synthesis and in maintaining insulin sensitivity, whereas, suppression of polyIC-mediated threonine phosphorylation of PKR by insulin compromises its ability to fight against virus infection in host cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. 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...

  8. Protein phosphorylation in bcterial signaling and regulation

    KAUST Repository

    Mijakovic, Ivan

    2016-01-01

    . Evolutionary studies based on genome comparison indicate that BY-kinases exist only in bacteria. They are non-essential (present in about 40% bacterial genomes), and their knockouts lead to pleiotropic phenotypes, since they phosphorylate many substrates

  9. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Directory of Open Access Journals (Sweden)

    Or Sperling

    Full Text Available Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq. cm(-3 yr(-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  10. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Science.gov (United States)

    Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm(-3) yr(-1) on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  11. A MEMS turbine prototype for respiration harvesting

    Science.gov (United States)

    Goreke, U.; Habibiabad, S.; Azgin, K.; Beyaz, M. I.

    2015-12-01

    The design, manufacturing, and performance characterization of a MEMS-scale turbine prototype is reported. The turbine is designed for integration into a respiration harvester that can convert normal human breathing into electrical power through electromagnetic induction. The device measures 10 mm in radius, and employs 12 blades located around the turbine periphery along with ball bearings around the center. Finite element simulations showed that an average torque of 3.07 μNm is induced at 12 lpm airflow rate, which lies in normal breathing levels. The turbine and a test package were manufactured using CNC milling on PMMA. Tests were performed at respiration flow rates between 5-25 lpm. The highest rotational speed was measured to be 9.84 krpm at 25 lpm, resulting in 8.96 mbar pressure drop across the device and 370 mW actuation power.

  12. Photochemical alteration of organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration.

    Science.gov (United States)

    Ward, Collin P; Nalven, Sarah G; Crump, Byron C; Kling, George W; Cory, Rose M

    2017-10-03

    In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO 2 . This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO 2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure. Using high-resolution chemical and microbial approaches, we show that rates of DOC processing by microbes are likely governed by a combination of the abundance and lability of DOC exported from land to water and produced by photochemical processes, and the capacity and timescale that microbial communities have to adapt to metabolize photo-altered DOC.The role of dissolved organic carbon (DOC) photo-alteration in the microbial respiration of DOC to CO 2 is unclear. Here, the authors show that the impact of this mechanism depends on whether photo-alteration of DOC produces or removes molecules used by native microbial communities prior to light exposure.

  13. Contribution of Cell Elongation to the Biofilm Formation of Pseudomonas aeruginosa during Anaerobic Respiration

    Science.gov (United States)

    Park, Yongjin; Yoon, Sang Sun

    2011-01-01

    Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO2 −) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process. PMID:21267455

  14. Reactive oxygen species contribute to arsenic-induced EZH2 phosphorylation in human bronchial epithelial cells and lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lingzhi; Qiu, Ping; Chen, Bailing; Lu, Yongju; Wu, Kai; Thakur, Chitra; Chang, Qingshan; Sun, Jiaying; Chen, Fei, E-mail: fchen@wayne.edu

    2014-05-01

    Our previous studies suggested that arsenic is able to induce serine 21 phosphorylation of the EZH2 protein through activation of JNK, STAT3, and Akt signaling pathways in the bronchial epithelial cell line, BEAS-2B. In the present report, we further demonstrated that reactive oxygen species (ROS) were involved in the arsenic-induced protein kinase activation that leads to EZH2 phosphorylation. Several lines of evidence supported this notion. First, the pretreatment of the cells with N-acetyl-L-cysteine (NAC), a potent antioxidant, abolishes arsenic-induced EZH2 phosphorylation along with the inhibition of JNK, STAT3, and Akt. Second, H{sub 2}O{sub 2}, the most important form of ROS in the cells in response to extracellular stress signals, can induce phosphorylation of the EZH2 protein and the activation of JNK, STAT3, and Akt. By ectopic expression of the myc-tagged EZH2, we additionally identified direct interaction and phosphorylation of the EZH2 protein by Akt in response to arsenic and H{sub 2}O{sub 2}. Furthermore, both arsenic and H{sub 2}O{sub 2} were able to induce the translocation of ectopically expressed or endogenous EZH2 from nucleus to cytoplasm. In summary, the data presented in this report indicate that oxidative stress due to ROS generation plays an important role in the arsenic-induced EZH2 phosphorylation. - Highlights:: • Arsenic (As{sup 3+}) induces EZH phosphorylation. • JNK, STAT3, and Akt contribute to EZH2 phosphorylation. • Oxidative stress is involved in As{sup 3+}-induced EZH2 phosphorylation. • As{sup 3+} induces direct interaction of Akt and EZH2. • Phosphorylated EZH2 localized in cytoplasm.

  15. Fibronectin phosphorylation by ecto-protein kinase

    International Nuclear Information System (INIS)

    Imada, Sumi; Sugiyama, Yayoi; Imada, Masaru

    1988-01-01

    The presence of membrane-associated, extracellular protein kinase (ecto-protein kinase) and its substrate proteins was examined with serum-free cultures of Swiss 3T3 fibroblast. When cells were incubated with [γ- 32 ]ATP for 10 min at 37 degree C, four proteins with apparent molecular weights between 150 and 220 kDa were prominently phosphorylated. These proteins were also radiolabeled by lactoperoxidase catalyzed iodination and were sensitive to mild tryptic digestion, suggesting that they localized on the cell surface or in the extracellular matrix. Phosphorylation of extracellular proteins with [γ- 32 P]ATP in intact cell culture is consistent with the existence of ecto-protein kinase. Anti-fibronectin antibody immunoprecipitated one of the phosphoproteins which comigrated with a monomer and a dimer form of fibronectin under reducing and nonreducing conditions of electrophoresis, respectively. The protein had affinity for gelatin as demonstrated by retention with gelatin-conjugated agarose. This protein substrate of ecto-protein kinase was thus concluded to be fibronectin. The sites of phosphorylation by ecto-protein kinase were compared with those of intracellularly phosphorylated fibronectin by the analysis of radiolabeled amino acids and peptides. Ecto-protein kinase phosphorylated fibronectin at serine and threonine residues which were distinct from the sites of intracellular fibronectin phosphorylation

  16. Phosphorylation of human skeletal muscle myosin

    International Nuclear Information System (INIS)

    Houston, M.E.; Lingley, M.D.; Stuart, D.S.; Hoffman-Goetz, L.

    1986-01-01

    Phosphorylation of the P-light chains (phosphorylatable light chains) in human skeletal muscle myosin was studied in vitro and in vivo under resting an d contracted conditions. biopsy samples from rested vastus lateralis muscle of male and female subjects were incubated in oxygenated physiological solution at 30 0 C. Samples frozen following a quiescent period showed the presence of only unphosphorylated P-light chains designated LC2f (light chain two of fast myosin) CL2s and LC2s'(light chains two of slow myosin). Treatment with caffeine (10 mM) or direct electrical stimulation resulted in the appearance of three additional bands which were identified as the phosphorylated forms of the P-light chains i.e. LC2f-P, LC2s-P and LC2s'-P. The presence of phosphate was confirmed by prior incubation with ( 30 P) orthophosphate. Muscle samples rapidly frozen from resting vastus lateralis muscle revealed the presence of unphosphorylated and phosphorylated P-light chains in approximately equal ratios. Muscle samples rapidly frozen following a maximal 10 second isometric contraction showed virtually only phosphorylated fast and slow P-light chains. These results reveal that the P-light chains in human fast and slow myosin may be rapidly phosphorylated, but the basal level of phosphorylation in rested human muscle considerably exceeds that observed in animal muscles studied in vitro or in situ

  17. Protein phosphorylation during coconut zygotic embryo development

    International Nuclear Information System (INIS)

    Islas-Flores, I.; Oropeza, C.; Hernandez-Sotomayor, S.M.T.

    1998-01-01

    Evidence was obtained on the occurrence of protein threonine, serine, and tyrosine (Tyr) kinases in developing coconut (Cocos nucifera L.) zygotic embryos, based on in vitro phosphorylation of proteins in the presence of [gamma-32P]ATP, alkaline treatment, and thin-layer chromatography analysis, which showed the presence of [32P]phosphoserine, [32P]phosphothreonine, and [32P]phosphotyrosine in [32P]-labeled protein hydrolyzates. Tyr kinase activity was further confirmed in extracts of embryos at different stages of development using antiphosphotyrosine monoclonal antibodies and the synthetic peptide derived from the amino acid sequence surrounding the phosphorylation site in pp60src (RR-SRC), which is specific for Tyr kinases. Anti-phosphotyrosine western blotting revealed a changing profile of Tyr-phosphorylated proteins during embryo development. Tyr kinase activity, as assayed using RR-SRC, also changed during embryo development, showing two peaks of activity, one during early and another during late embryo development. In addition, the use of genistein, a Tyr kinase inhibitor, diminished the ability of extracts to phosphorylate RR-SRC. Results presented here show the occurrence of threonine, serine, and Tyr kinases in developing coconut zygotic embryos, and suggest that protein phosphorylation, and the possible inference of Tyr phosphorylation in particular, may play a role in the coordination of the development of embryos in this species

  18. PKA regulates calcineurin function through the phosphorylation of RCAN1: Identification of a novel phosphorylation site

    International Nuclear Information System (INIS)

    Kim, Seon Sook; Lee, Eun Hye; Lee, Kooyeon; Jo, Su-Hyun; Seo, Su Ryeon

    2015-01-01

    Calcineurin is a calcium/calmodulin-dependent phosphatase that has been implicated in T cell activation through the induction of nuclear factors of activated T cells (NFAT). We have previously suggested that endogenous regulator of calcineurin (RCAN1, also known as DSCR1) is targeted by protein kinase A (PKA) for the control of calcineurin activity. In the present study, we characterized the PKA-mediated phosphorylation site in RCAN1 by mass spectrometric analysis and revealed that PKA directly phosphorylated RCAN1 at the Ser 93. PKA-induced phosphorylation and the increase in the half-life of the RCAN1 protein were prevented by the substitution of Ser 93 with Ala (S93A). Furthermore, the PKA-mediated phosphorylation of RCAN1 at Ser 93 potentiated the inhibition of calcineurin-dependent pro-inflammatory cytokine gene expression by RCAN1. Our results suggest the presence of a novel phosphorylation site in RCAN1 and that its phosphorylation influences calcineurin-dependent inflammatory target gene expression. - Highlights: • We identify novel phosphorylation sites in RCAN1 by LC-MS/MS analysis. • PKA-dependent phosphorylation of RCAN1 at Ser 93 inhibits calcineurin-mediated intracellular signaling. • We show the immunosuppressive function of RCAN1 phosphorylation at Ser 93 in suppressing cytokine expression

  19. Mcm2 phosphorylation and the response to replicative stress

    Directory of Open Access Journals (Sweden)

    Stead Brent E

    2012-05-01

    Full Text Available Abstract Background The replicative helicase in eukaryotic cells is comprised of minichromosome maintenance (Mcm proteins 2 through 7 (Mcm2-7 and is a key target for regulation of cell proliferation. In addition, it is regulated in response to replicative stress. One of the protein kinases that targets Mcm2-7 is the Dbf4-dependent kinase Cdc7 (DDK. In a previous study, we showed that alanine mutations of the DDK phosphorylation sites at S164 and S170 in Saccharomyces cerevisiae Mcm2 result in sensitivity to caffeine and methyl methanesulfonate (MMS leading us to suggest that DDK phosphorylation of Mcm2 is required in response to replicative stress. Results We show here that a strain with the mcm2 allele lacking DDK phosphorylation sites (mcm2AA is also sensitive to the ribonucleotide reductase inhibitor, hydroxyurea (HU and to the base analogue 5-fluorouracil (5-FU but not the radiomimetic drug, phleomycin. We screened the budding yeast non-essential deletion collection for synthetic lethal interactions with mcm2AA and isolated deletions that include genes involved in the control of genome integrity and oxidative stress. In addition, the spontaneous mutation rate, as measured by mutations in CAN1, was increased in the mcm2AA strain compared to wild type, whereas with a phosphomimetic allele (mcm2EE the mutation rate was decreased. These results led to the idea that the mcm2AA strain is unable to respond properly to DNA damage. We examined this by screening the deletion collection for suppressors of the caffeine sensitivity of mcm2AA. Deletions that decrease spontaneous DNA damage, increase homologous recombination or slow replication forks were isolated. Many of the suppressors of caffeine sensitivity suppressed other phenotypes of mcm2AA including sensitivity to genotoxic drugs, the increased frequency of cells with RPA foci and the increased mutation rate. Conclusions Together these observations point to a role for DDK-mediated phosphorylation

  20. Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

    DEFF Research Database (Denmark)

    Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene Mark

    2015-01-01

    Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted the importance of anaerobic ammonium oxidation, anammox, in pelagic nitrogen removal. Sources of ammonium for the anammox reaction, however, remain controversial, as heterotrophic denitrifica......Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted the importance of anaerobic ammonium oxidation, anammox, in pelagic nitrogen removal. Sources of ammonium for the anammox reaction, however, remain controversial, as heterotrophic...... denitrification and alternative anaerobic pathways of organic matter remineralization cannot account for the ammonium requirements of reported anammox rates. Here, we explore the significance of microaerobic respiration as a source of ammonium during organic matter degradation in the oxygen-deficient waters off...... Namibia and Peru. Experiments with additions of double-labelled oxygen revealed high aerobic activity in the upper OMZs, likely controlled by surface organic matter export. Consistently observed oxygen consumption in samples retrieved throughout the lower OMZs hints at efficient exploitation of vertically...

  1. Plant species richness regulates soil respiration through changes in productivity.

    Science.gov (United States)

    Dias, André Tavares Corrêa; van Ruijven, Jasper; Berendse, Frank

    2010-07-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of diversity on soil respiration. We hypothesized that plant diversity could affect soil respiration in two ways. On the one hand, more diverse plant communities have been shown to promote plant productivity, which could increase soil respiration. On the other hand, the nutrient concentration in the biomass produced has been shown to decrease with diversity, which could counteract the production-induced increase in soil respiration. Our results clearly show that soil respiration increased with species richness. Detailed analysis revealed that this effect was not due to differences in species composition. In general, soil respiration in mixtures was higher than would be expected from the monocultures. Path analysis revealed that species richness predominantly regulates soil respiration through changes in productivity. No evidence supporting the hypothesized negative effect of lower N concentration on soil respiration was found. We conclude that shifts in productivity are the main mechanism by which changes in plant diversity may affect soil respiration.

  2. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    Science.gov (United States)

    Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

    2016-04-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2, and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

  3. ROS-activated ATM-dependent phosphorylation of cytoplasmic substrates identified by large scale phosphoproteomics screen

    DEFF Research Database (Denmark)

    Kozlov, Sergei V; Waardenberg, Ashley J; Engholm-Keller, Kasper

    2016-01-01

    ATM (ataxia-telangiectasia, mutated) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signalling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoi......ATM (ataxia-telangiectasia, mutated) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signalling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle...... checkpoints, initiating DNA repair and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach...... to identify cytoplasmic proteins altered in their phosphorylation state in control and A-T (ataxia-telangiectasia) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites...

  4. The role of alternative cyanide-insensitive respiration in plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Raskin, Ilya

    1997-09-29

    This DOE funded research concentrated on the investigation of the role of respiration and oxidative stress in plant biology. Initially the authors concentrated on the possible role of cyanide-insensitive respiration in counteracting the deleterious effects of chilling stress. Although plants are considered to be poikilotherms, there are a few examples of thermogenesis, in which the tissue temperature increases well above ambient. They suggested that differences between thermogenic and non-thermogenic plants may be quantitative rather than qualitative, and that heat from increased respiration may have a local protective effect on the mitochondria, slowing or reducing the effects of chilling. They proposed that this is accomplished by a large increase in respiration, predominantly via the alternative pathway. They measured the increases in respiration, particularly via the alternative pathway, in response to chilling. They have also quantified the associated increases in heat evolution in response to chilling in a number of plant species using a microcalorimeter. For example, after 8 h exposure to 8 C, heat evolution in chilling-sensitive species increased 47--98%, compared to 7--22% for the chilling-resistant species. No increase in heat evolution was observed in the extremely chilling-sensitive ornamental Episcka cupreata (Hook). Increases in heat evolution were observed when plants were chilled in constant light or in the dark, but not when plants were chilled at high humidity. Heat evolution by mitochondria isolated from potato tuber slices were also measured. These values, together with measurements of the heat capacity of isolated mitochondria and counting of the mitochondria by flow cytometry, allow calculation of theoretical maximal rates of heating and the heat produced per mitochondrion. The obtained data was consistent with the protective role of respiratory heat production in cold-stressed plants.

  5. HIF and reactive oxygen species regulate oxidative phosphorylation in cancer

    Czech Academy of Sciences Publication Activity Database

    Hervouet, E.; Čížková, Alena; Demont, J.; Vojtíšková, Alena; Pecina, Petr; Franssen-van Hal, N.; Keijer, J.; Simonnet, H.; Ivánek, Robert; Kmoch, S.; Godinot, C.; Houštěk, Josef

    2008-01-01

    Roč. 29, č. 8 (2008), s. 1528-1537 ISSN 0143-3334 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR GA303/07/0781 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z50520514 Keywords : carcinoma * mitochondrial biogenesis * reactive oxygen species Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.930, year: 2008

  6. Protein phosphorylation systems in postmortem human brain

    International Nuclear Information System (INIS)

    Walaas, S.I.; Perdahl-Wallace, E.; Winblad, B.; Greengard, P.

    1989-01-01

    Protein phosphorylation systems regulated by cyclic adenosine 3',5'-monophosphate (cyclic AMP), or calcium in conjunction with calmodulin or phospholipid/diacylglycerol, have been studied by phosphorylation in vitro of particulate and soluble fractions from human postmortem brain samples. One-dimensional or two-dimensional gel electrophoretic protein separations were used for analysis. Protein phosphorylation catalyzed by cyclic AMP-dependent protein kinase was found to be highly active in both particulate and soluble preparations throughout the human CNS, with groups of both widely distributed and region-specific substrates being observed in different brain nuclei. Dopamine-innervated parts of the basal ganglia and cerebral cortex contained the phosphoproteins previously observed in rodent basal ganglia. In contrast, calcium/phospholipid-dependent and calcium/calmodulin-dependent protein phosphorylation systems were less prominent in human postmortem brain than in rodent brain, and only a few widely distributed substrates for these protein kinases were found. Protein staining indicated that postmortem proteolysis, particularly of high-molecular-mass proteins, was prominent in deeply located, subcortical regions in the human brain. Our results indicate that it is feasible to use human postmortem brain samples, when obtained under carefully controlled conditions, for qualitative studies on brain protein phosphorylation. Such studies should be of value in studies on human neurological and/or psychiatric disorders

  7. Partitioning of ecosystem respiration in a beech forest

    DEFF Research Database (Denmark)

    Brændholt, Andreas; Ibrom, Andreas; Larsen, Klaus Steenberg

    2018-01-01

    Terrestrial ecosystem respiration (Reco) represents a major component of the global carbon cycle. It consists of many sub-components, such as aboveground plant respiration and belowground root and microbial respiration, each of which may respond differently to abiotic factors, and thus to global...... of Reco in a temperate beech forest at diel, seasonal and annual time scales. Reco was measured by eddy covariance while respiration rates from soil, tree stems and isolated coarse tree roots were measured bi-hourly by an automated closed-chamber system. Soil respiration (Rsoil) was measured in intact...... plots, and heterotrophic Rsoil was measured in trenched plots. Tree stem (Rstem) and coarse root (Rroot) respiration were measured by custom made closed-chambers. We found that the contribution of Rstem to total Reco varied across the year, by only accounting for 6% of Reco during winter and 16% during...

  8. Tillage Effects on Soil Properties & Respiration

    Science.gov (United States)

    Rusu, Teodor; Bogdan, Ileana; Moraru, Paula; Pop, Adrian; Duda, Bogdan; Cacovean, Horea; Coste, Camelia

    2015-04-01

    Soil tillage systems can be able to influence soil compaction, water dynamics, soil temperature and soil structural condition. These processes can be expressed as changes of soil microbiological activity, soil respiration and sustainability of agriculture. Objectives of this study were: 1) to assess the effects of tillage systems (Conventional System-CS, Minimum Tillage-MT, No-Tillage-NT) on soil compaction, soil temperature, soil moisture and soil respiration and 2) to establish the relationship that exists in changing soil properties. Three treatments were installed: CS-plough + disc; MT-paraplow + rotary grape; NT-direct sowing. The study was conducted on an Argic-Stagnic Faeoziom. The MT and NT applications reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first year of application. The degree of compaction is directly related to soil type and its state of degradation. The state of soil compaction diminished over time, tending toward a specific type of soil density. Soil moisture was higher in NT and MT at the time of sowing and in the early stages of vegetation and differences diminished over time. Moisture determinations showed statistically significant differences. The MT and NT applications reduced the thermal amplitude in the first 15 cm of soil depth and increased the soil temperature by 0.5-2.20C. The determinations confirm the effect of soil tillage system on soil respiration; the daily average was lower at NT (315-1914 mmoli m-2s-1) and followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Comparing with CS, all the two conservation tillage measures decreased soil respiration, with the best effects of no-tillage. An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of

  9. Maintenance, endogeneous, respiration, lysis, decay and predation

    DEFF Research Database (Denmark)

    loosdrecht, Marc C. M. Van; Henze, Mogens

    1999-01-01

    mechanism is microbiologically correct. The lysis/decay model mechanism is a strongly simplified representation of reality. This paper tries to review the processes grouped under endogenous respiration in activated sludge models. Mechanisms and processes such as maintenance, lysis, internal and external...... decay, predation and death-regeneration are discussed. From recent microbial research it has become evident that cells do not die by themselves. Bacteria are however subject to predation by protozoa. Bacteria store reserve polymers that in absence of external substrate are used for growth...

  10. Development of an Advanced Respirator Fit Test Headform (Postprint)

    Science.gov (United States)

    2012-11-01

    N95 filtering facepiece respirators (FFRs) for pro - tection studies against viable airborne particles. A Static (i.e., non-moving, non-speaking...requiredto wear respirators to reduce their exposure to air- borne hazards.(1) The U.S. Occupational Safety and Health Administration ( OSHA ) Respiratory...13 workplace protection factors.(9,10). Inward leakage (IL) of con - taminants into a respirator facepiece has been described as a combination of

  11. Soil Respiration under Different Land Uses in Eastern China

    Science.gov (United States)

    Fan, Li-Chao; Yang, Ming-Zhen; Han, Wen-Yan

    2015-01-01

    Land-use change has a crucial influence on soil respiration, which further affects soil nutrient availability and carbon stock. We monitored soil respiration rates under different land-use types (tea gardens with three production levels, adjacent woodland, and a vegetable field) in Eastern China at weekly intervals over a year using the dynamic closed chamber method. The relationship between soil respiration and environmental factors was also evaluated. The soil respiration rate exhibited a remarkable single peak that was highest in July/August and lowest in January. The annual cumulative respiration flux increased by 25.6% and 20.9% in the tea garden with high production (HP) and the vegetable field (VF), respectively, relative to woodland (WL). However, no significant differences were observed between tea gardens with medium production (MP), low production (LP), WL, and VF. Soil respiration rates were significantly and positively correlated with organic carbon, total nitrogen, and available phosphorous content. Each site displayed a significant exponential relationship between soil respiration and soil temperature measured at 5 cm depth, which explained 84–98% of the variation in soil respiration. The model with a combination of soil temperature and moisture was better at predicting the temporal variation of soil respiration rate than the single temperature model for all sites. Q10 was 2.40, 2.00, and 1.86–1.98 for VF, WL, and tea gardens, respectively, indicating that converting WL to VF increased and converting to tea gardens decreased the sensitivity of soil respiration to temperature. The equation of the multiple linear regression showed that identical factors, including soil organic carbon (SOC), soil water content (SWC), pH, and water soluble aluminum (WSAl), drove the changes in soil respiration and Q10 after conversion of land use. Temporal variations of soil respiration were mainly controlled by soil temperature, whereas spatial variations were

  12. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    Unknown

    The linear regression relationship between soil respiration and root biomass was used to determine the .... 10 days, sieved 50 g soil samples were placed in a 100 ml beaker and a 250 ..... Comparatively, the method can take multi-samples by ...

  13. ESTIMATING ROOT RESPIRATION IN SPRUCE AND BEECH: DECREASES IN SOIL RESPIRATION FOLLOWING GIRDLING

    Science.gov (United States)

    A study was undertaken to follow seasonal fluxes of CO2 from soil and to estimate the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) in a mixed stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Matu...

  14. Nicotinamide supplementation phenocopies SIR2 inactivation by modulating carbon metabolism and respiration during yeast chronological aging.

    Science.gov (United States)

    Orlandi, Ivan; Pellegrino Coppola, Damiano; Strippoli, Maurizio; Ronzulli, Rossella; Vai, Marina

    2017-01-01

    Nicotinamide (NAM), a form of vitamin B 3 , is a byproduct and noncompetitive inhibitor of the deacetylation reaction catalyzed by Sirtuins. These represent a family of evolutionarily conserved NAD + -dependent deacetylases that are well-known critical regulators of metabolism and aging and whose founding member is Sir2 of Saccharomyces cerevisiae. Here, we investigated the effects of NAM supplementation in the context of yeast chronological aging, the established model for studying aging of postmitotic quiescent mammalian cells. Our data show that NAM supplementation at the diauxic shift results in a phenocopy of chronologically aging sir2Δ cells. In fact, NAM-supplemented cells display the same chronological lifespan extension both in expired medium and extreme Calorie Restriction. Furthermore, NAM allows the cells to push their metabolism toward the same outcomes of sir2Δ cells by elevating the level of the acetylated Pck1. Both these cells have the same metabolic changes that concern not only anabolic pathways such as an increased gluconeogenesis but also respiratory activity in terms both of respiratory rate and state of respiration. In particular, they have a higher respiratory reserve capacity and a lower non-phosphorylating respiration that in concert with a low burden of superoxide anions can affect positively chronological aging. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Src kinase regulation by phosphorylation and dephosphorylation

    International Nuclear Information System (INIS)

    Roskoski, Robert

    2005-01-01

    Src and Src-family protein-tyrosine kinases are regulatory proteins that play key roles in cell differentiation, motility, proliferation, and survival. The initially described phosphorylation sites of Src include an activating phosphotyrosine 416 that results from autophosphorylation, and an inhibiting phosphotyrosine 527 that results from phosphorylation by C-terminal Src kinase (Csk) and Csk homologous kinase. Dephosphorylation of phosphotyrosine 527 increases Src kinase activity. Candidate phosphotyrosine 527 phosphatases include cytoplasmic PTP1B, Shp1 and Shp2, and transmembrane enzymes include CD45, PTPα, PTPε, and PTPλ. Dephosphorylation of phosphotyrosine 416 decreases Src kinase activity. Thus far PTP-BL, the mouse homologue of human PTP-BAS, has been shown to dephosphorylate phosphotyrosine 416 in a regulatory fashion. The platelet-derived growth factor receptor protein-tyrosine kinase mediates the phosphorylation of Src Tyr138; this phosphorylation has no direct effect on Src kinase activity. The platelet-derived growth factor receptor and the ErbB2/HER2 growth factor receptor protein-tyrosine kinases mediate the phosphorylation of Src Tyr213 and activation of Src kinase activity. Src kinase is also a substrate for protein-serine/threonine kinases including protein kinase C (Ser12), protein kinase A (Ser17), and CDK1/cdc2 (Thr34, Thr46, and Ser72). Of the three protein-serine/threonine kinases, only phosphorylation by CDK1/cdc2 has been demonstrated to increase Src kinase activity. Although considerable information on the phosphoprotein phosphatases that catalyze the hydrolysis of Src phosphotyrosine 527 is at hand, the nature of the phosphatases that mediate the hydrolysis of phosphotyrosine 138 and 213, and phosphoserine and phosphothreonine residues has not been determined

  16. Respiration triggers heme transfer from cytochrome c peroxidase to catalase in yeast mitochondria

    Science.gov (United States)

    Kathiresan, Meena; Martins, Dorival; English, Ann M.

    2014-01-01

    In exponentially growing yeast, the heme enzyme, cytochrome c peroxidase (Ccp1) is targeted to the mitochondrial intermembrane space. When the fermentable source (glucose) is depleted, cells switch to respiration and mitochondrial H2O2 levels rise. It has long been assumed that CCP activity detoxifies mitochondrial H2O2 because of the efficiency of this activity in vitro. However, we find that a large pool of Ccp1 exits the mitochondria of respiring cells. We detect no extramitochondrial CCP activity because Ccp1 crosses the outer mitochondrial membrane as the heme-free protein. In parallel with apoCcp1 export, cells exhibit increased activity of catalase A (Cta1), the mitochondrial and peroxisomal catalase isoform in yeast. This identifies Cta1 as a likely recipient of Ccp1 heme, which is supported by low Cta1 activity in ccp1Δ cells and the accumulation of holoCcp1 in cta1Δ mitochondria. We hypothesized that Ccp1’s heme is labilized by hyperoxidation of the protein during the burst in H2O2 production as cells begin to respire. To test this hypothesis, recombinant Ccp1 was hyperoxidized with excess H2O2 in vitro, which accelerated heme transfer to apomyoglobin added as a surrogate heme acceptor. Furthermore, the proximal heme Fe ligand, His175, was found to be ∼85% oxidized to oxo-histidine in extramitochondrial Ccp1 isolated from 7-d cells, indicating that heme labilization results from oxidation of this ligand. We conclude that Ccp1 responds to respiration-derived H2O2 via a previously unidentified mechanism involving H2O2-activated heme transfer to apoCta1. Subsequently, the catalase activity of Cta1, not CCP activity, contributes to mitochondrial H2O2 detoxification. PMID:25422453

  17. Respiration triggers heme transfer from cytochrome c peroxidase to catalase in yeast mitochondria.

    Science.gov (United States)

    Kathiresan, Meena; Martins, Dorival; English, Ann M

    2014-12-09

    In exponentially growing yeast, the heme enzyme, cytochrome c peroxidase (Ccp1) is targeted to the mitochondrial intermembrane space. When the fermentable source (glucose) is depleted, cells switch to respiration and mitochondrial H2O2 levels rise. It has long been assumed that CCP activity detoxifies mitochondrial H2O2 because of the efficiency of this activity in vitro. However, we find that a large pool of Ccp1 exits the mitochondria of respiring cells. We detect no extramitochondrial CCP activity because Ccp1 crosses the outer mitochondrial membrane as the heme-free protein. In parallel with apoCcp1 export, cells exhibit increased activity of catalase A (Cta1), the mitochondrial and peroxisomal catalase isoform in yeast. This identifies Cta1 as a likely recipient of Ccp1 heme, which is supported by low Cta1 activity in ccp1Δ cells and the accumulation of holoCcp1 in cta1Δ mitochondria. We hypothesized that Ccp1's heme is labilized by hyperoxidation of the protein during the burst in H2O2 production as cells begin to respire. To test this hypothesis, recombinant Ccp1 was hyperoxidized with excess H2O2 in vitro, which accelerated heme transfer to apomyoglobin added as a surrogate heme acceptor. Furthermore, the proximal heme Fe ligand, His175, was found to be ∼ 85% oxidized to oxo-histidine in extramitochondrial Ccp1 isolated from 7-d cells, indicating that heme labilization results from oxidation of this ligand. We conclude that Ccp1 responds to respiration-derived H2O2 via a previously unidentified mechanism involving H2O2-activated heme transfer to apoCta1. Subsequently, the catalase activity of Cta1, not CCP activity, contributes to mitochondrial H2O2 detoxification.

  18. [The development of a respiration and temperature monitor].

    Science.gov (United States)

    Du, X; Wu, B; Liu, Y; He, Q; Xiao, J

    2001-12-01

    This paper introduces the design of a monitoring system to measure the respiration and temperature of a body with an 8Xc196 single-chip microcomputer. This system can measure and display the respiration wave, respiration frequency and the body temperature in real-time with a liquid crystal display (LCD) and give an alarm when the parameters are beyond the normal scope. In addition, this device can provide a 24 hours trend graph of the respiration frequency and the body temperature parameters measured. Data can also be exchanged through serial communication interfaces (RS232) between the PC and the monitor.

  19. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...... consortia. Despite the potentially adverse effects, only few inorganic electron acceptors potentially utilizable for anaerobic respiration have been investigated with respect to negative interactions in anaerobic digesters. In this chapter we review competitive and inhibitory interactions between anaerobic...... respiring populations and methanogenic consortia in bioreactors. Due to the few studies in anaerobic digesters, many of our discussions are based upon studies of defined cultures or natural ecosystems...

  20. Respirator studies for the ERDA Division of Safety, Standards, and Compliance. Progress report, July 1, 1974--June 30, 1975

    International Nuclear Information System (INIS)

    Douglas, D.D.; Hack, A.L.; Davis, T.O.; Shafer, C.; Moore, T.O.; Richards, C.P.; Revoir, W.H.

    1976-08-01

    Major accomplishments during FY 1975 were the initiation of a respirator research program to investigate the physiological effects of wearing a respirator under stress, assisting ERDA contractors by providing information and training concerning respirator programs, quality assurance of respirators, and respirator applications. A newsletter of respirator developments for ERDA contractor personnel was published, and a Respirator Symposium was conducted

  1. PKM2 Thr454 phosphorylation increases its nuclear translocation and promotes xenograft tumor growth in A549 human lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhenhai, E-mail: tomsyu@163.com [Center for Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, 261031 (China); Huang, Liangqian [Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS) & Shanghai Jiao Tong University School of Medicine -SJTUSM, Shanghai, 200025 (China); Qiao, Pengyun; Jiang, Aifang; Wang, Li; Yang, Tingting [Center for Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, 261031 (China); Tang, Shengjian; Zhang, Wei [Plastic Surgery Institute of Weifang Medical University, Weifang, Shandong, 261041 (China); Ren, Chune, E-mail: ren@wfmc.edu.cn [Center for Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, 261031 (China)

    2016-05-13

    Pyruvate kinase M2 (PKM2) is a key enzyme of glycolysis which is highly expressed in many tumor cells, and plays an important role in the Warburg effect. In previous study, we found PIM2 phosphorylates PKM2 at Thr454 residue (Yu, etl 2013). However, the functions of PKM2 Thr454 modification in cancer cells still remain unclear. Here we find PKM2 translocates into the nucleus after Thr454 phosphorylation. Replacement of wild type PKM2 with a mutant (T454A) enhances mitochondrial respiration, decreases pentose phosphate pathway, and enhances chemosensitivity in A549 cells. In addition, the mutant (T454A) PKM2 reduces xenograft tumor growth in nude mice. These findings demonstrate that PKM2 T454 phosphorylation is a potential therapeutic target in lung cancer.

  2. Penetration of asbestos fibers in respirator filters

    International Nuclear Information System (INIS)

    Cheng, Yung-Sung; Pearson, S.D.; Rohrbacher, K.D.; Yeh, Hsu-Chi.

    1994-01-01

    Currently, the health risks associated with asbestos have restricted its use and created a growing asbestos abatement industry with a need for respirator filters that are effective for worker protection. The main purpose of this project is to determine the influence of fiber size, electrostatic charge, and flow rate on the penetration of asbestos fibers in respirator filter cartridges. The study includes four types of filters each tested at two flow rates: the AO-R57A, a dual cartridge HEPA filter tested at 16 and 42.5 L/min; the MSA-S, a dust and mist filter tested at 16 and 42.5 L/min; the MSA-A power filter tested at 32 and 85 L/min; and the 3M-8710, a low-efficiency disposable face mask filter tested at 32 and 85 L/min. The three types of asbestos fibers used (amosite, crocidolite, and chrysotile) ranged in length from 0.04-0.5 μm and in aspect ratio (ratio of length to diameter) from 3 to 60. The fibers were used in both charged and neutralized forms. The results from amosite fibers are reported here

  3. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    Science.gov (United States)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  4. High concentrations of H2O2 make aerobic glycolysis energetically more favourable than cellular respiration.

    Directory of Open Access Journals (Sweden)

    Hamid R Molavian

    2016-08-01

    Full Text Available Since the original observation of the Warburg Effect in cancer cells, over eight decades ago, the major question of why aerobic glycolysis is favored over oxidative phosphorylation has remained unresolved. An understanding of this phenomenon may well be the key to the development of more effective cancer therapies. In this paper, we use a semi-empirical method to throw light on this puzzle. We show that aerobic glycolysis is in fact energetically more favorable than oxidative phosphorylation for concentrations of peroxide (H2O2 above some critical threshold value. The fundamental reason for this is the activation and high engagement of the pentose phosphate pathway (PPP in response to the production of reactive oxygen species H2O2 by mitochondria and the high concentration of H2O2 (produced by mitochondria and other sources. This makes oxidative phosphorylation an inefficient source of energy since it leads (despite high levels of ATP production to a concomitant high energy consumption in order to respond to the hazardous waste products resulting from cellular processes associated with this metabolic pathway. We also demonstrate that the high concentration of H2O2 results in an increased glucose consumption, and also increases the lactate production in the case of glycolysis.

  5. Quantitative phosphoproteomics reveals the role of protein arginine phosphorylation in the bacterial stress response.

    Science.gov (United States)

    Schmidt, Andreas; Trentini, Débora Broch; Spiess, Silvia; Fuhrmann, Jakob; Ammerer, Gustav; Mechtler, Karl; Clausen, Tim

    2014-02-01

    Arginine phosphorylation is an emerging protein modification implicated in the general stress response of Gram-positive bacteria. The modification is mediated by the arginine kinase McsB, which phosphorylates and inactivates the heat shock repressor CtsR. In this study, we developed a mass spectrometric approach accounting for the peculiar chemical properties of phosphoarginine. The improved methodology was used to analyze the dynamic changes in the Bacillus subtilis arginine phosphoproteome in response to different stress situations. Quantitative analysis showed that a B. subtilis mutant lacking the YwlE arginine phosphatase accumulated a strikingly large number of arginine phosphorylations (217 sites in 134 proteins), however only a minor fraction of these sites was increasingly modified during heat shock or oxidative stress. The main targets of McsB-mediated arginine phosphorylation comprise central factors of the stress response system including the CtsR and HrcA heat shock repressors, as well as major components of the protein quality control system such as the ClpCP protease and the GroEL chaperonine. These findings highlight the impact of arginine phosphorylation in orchestrating the bacterial stress response.

  6. Proteasome phosphorylation regulates cocaine-induced sensitization.

    Science.gov (United States)

    Gonzales, Frankie R; Howell, Kristin K; Dozier, Lara E; Anagnostaras, Stephan G; Patrick, Gentry N

    2018-04-01

    Repeated exposure to cocaine produces structural and functional modifications at synapses from neurons in several brain regions including the nucleus accumbens. These changes are thought to underlie cocaine-induced sensitization. The ubiquitin proteasome system plays a crucial role in the remodeling of synapses and has recently been implicated in addiction-related behavior. The ATPase Rpt6 subunit of the 26S proteasome is phosphorylated by Ca 2+ /calmodulin-dependent protein kinases II alpha at ser120 which is thought to regulate proteasome activity and distribution in neurons. Here, we demonstrate that Rpt6 phosphorylation is involved in cocaine-induced locomotor sensitization. Cocaine concomitantly increases proteasome activity and Rpt6 S120 phosphorylation in cultured neurons and in various brain regions of wild type mice including the nucleus accumbens and prefrontal cortex. In contrast, cocaine does not increase proteasome activity in Rpt6 phospho-mimetic (ser120Asp) mice. Strikingly, we found a complete absence of cocaine-induced locomotor sensitization in the Rpt6 ser120Asp mice. Together, these findings suggest a critical role for Rpt6 phosphorylation and proteasome function in the regulation cocaine-induced behavioral plasticity. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 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

  8. Tyrosine phosphorylation switching of a G protein.

    Science.gov (United States)

    Li, Bo; Tunc-Ozdemir, Meral; Urano, Daisuke; Jia, Haiyan; Werth, Emily G; Mowrey, David D; Hicks, Leslie M; Dokholyan, Nikolay V; Torres, Matthew P; Jones, Alan M

    2018-03-30

    Heterotrimeric G protein complexes are molecular switches relaying extracellular signals sensed by G protein-coupled receptors (GPCRs) to downstream targets in the cytoplasm, which effect cellular responses. In the plant heterotrimeric GTPase cycle, GTP hydrolysis, rather than nucleotide exchange, is the rate-limiting reaction and is accelerated by a receptor-like regulator of G signaling (RGS) protein. We hypothesized that posttranslational modification of the Gα subunit in the G protein complex regulates the RGS-dependent GTPase cycle. Our structural analyses identified an invariant phosphorylated tyrosine residue (Tyr 166 in the Arabidopsis Gα subunit AtGPA1) located in the intramolecular domain interface where nucleotide binding and hydrolysis occur. We also identified a receptor-like kinase that phosphorylates AtGPA1 in a Tyr 166 -dependent manner. Discrete molecular dynamics simulations predicted that phosphorylated Tyr 166 forms a salt bridge in this interface and potentially affects the RGS protein-accelerated GTPase cycle. Using a Tyr 166 phosphomimetic substitution, we found that the cognate RGS protein binds more tightly to the GDP-bound Gα substrate, consequently reducing its ability to accelerate GTPase activity. In conclusion, we propose that phosphorylation of Tyr 166 in AtGPA1 changes the binding pattern with AtRGS1 and thereby attenuates the steady-state rate of the GTPase cycle. We coin this newly identified mechanism "substrate phosphoswitching." © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Physiological quality and seed respiration of primed Jatropha curcas seeds

    Directory of Open Access Journals (Sweden)

    Micheli Angelica Horbach

    2017-11-01

    Full Text Available ABSTRACT Seed deterioration is a natural and irreversible process. Nevertheless, seed priming with water and antioxidants can minimize oxidative damage in oilseeds, resulting in attenuation of seed deterioration. The objective of this assay was to evaluate seed priming on respiratory activity of Jatropha curcas submitted to accelerated aging. Seeds from two provenances (Janauba and Pedro J. Caballero were submitted to three priming treatments (control, immersion in deionized water, and with 750 µmol L-1 of ascorbic acid and treated for accelerated aging at 41 °C for 72 h. The results showed that the priming of J. curcas seeds promoted tolerance to accelerated aging. Primed seeds, with ascorbic acid from Janauba and deionized water from Pedro J. Caballero, resulted in a higher percentage of normal seedlings, and increased germination speed index and seed respiration. The decline of physiological quality of J. curcas seeds after accelerated aging is directly associated with a reduction in respiratory activity that is related to seed moisture content.

  10. In situ respiration testing: A field treatability test for bioventing

    International Nuclear Information System (INIS)

    Kittel, J.A.; Hinchee, R.E.; Miller, R.; Vogel, C.; Hoeppel, R.

    1993-01-01

    Bioventing is the process of aerating subsurface soils to stimulate in situ biological activity and promote bioremediation. Bioventing differs from soil venting in remedial approach. Soil venting is designed and operated to maximize the volatilization of low-molecular-weight compounds, with some biodegradation occurring. In contrast, bioventing is designed to maximize biodegradation of aerobically biodegradable compounds, regardless of their molecular weight, with some volatilization occurring. Bioventing is gaining wide acceptance as a remediation alternative at petroleum-contaminated sites. However, site variability usually requires that a short term treatability test be conducted in situ at potential sites to determine the applicability of bioventing. Battelle has worked with the US Air Force and the US Navy to develop a simple and inexpensive field test to evaluate bioventing potential-contaminated sites. This test has been used to evaluate the applicability of bioventing at over 50 sites. The in situ respiration test consists of injecting air and an inert tracer gas (helium) over a 24-hour period to aerate soils at an oxygen-deficient, petroleum-contaminated site. Soil vapor samples are collected to determine oxygen utilization rates and carbon dioxide production rates. The stoichiometric relationship for the oxidation of hexane is used to calculate the biodegradation rate. The tracer gas is monitored to estimate the effect of diffusion on changes in soil-gas concentrations

  11. Visible light alters yeast metabolic rhythms by inhibiting respiration.

    Science.gov (United States)

    Robertson, James Brian; Davis, Chris R; Johnson, Carl Hirschie

    2013-12-24

    Exposure of cells to visible light in nature or in fluorescence microscopy often is considered to be relatively innocuous. However, using the yeast respiratory oscillation (YRO) as a sensitive measurement of metabolism, we find that non-UV visible light has a significant impact on yeast metabolism. Blue/green wavelengths of visible light shorten the period and dampen the amplitude of the YRO, which is an ultradian rhythm of cell metabolism and transcription. The wavelengths of light that have the greatest effect coincide with the peak absorption regions of cytochromes. Moreover, treating yeast with the electron transport inhibitor sodium azide has similar effects on the YRO as visible light. Because impairment of respiration by light would change several state variables believed to play vital roles in the YRO (e.g., oxygen tension and ATP levels), we tested oxygen's role in YRO stability and found that externally induced oxygen depletion can reset the phase of the oscillation, demonstrating that respiratory capacity plays a role in the oscillation's period and phase. Light-induced damage to the cytochromes also produces reactive oxygen species that up-regulate the oxidative stress response gene TRX2 that is involved in pathways that enable sustained growth in bright visible light. Therefore, visible light can modulate cellular rhythmicity and metabolism through unexpectedly photosensitive pathways.

  12. Simulation of Human Respiration with Breathing Thermal Manikin

    DEFF Research Database (Denmark)

    Bjørn, Erik

    The human respiration contains carbon dioxide, bioeffluents, and perhaps virus or bacteria. People may also indulge in activities that produce contaminants, as for example tobacco smoking. For these reasons, the human respiration remains one of the main contributors to contamination of the indoor...

  13. Interpreting diel hysteresis between soil respiration and temperature

    Science.gov (United States)

    C. Phillips; N. Nickerson; D. Risk; B.J. Bond

    2011-01-01

    Increasing use of automated soil respiration chambers in recent years has demonstrated complex diel relationships between soil respiration and temperature that are not apparent from less frequent measurements. Soil surface flux is often lagged from soil temperature by several hours, which results in semielliptical hysteresis loops when surface flux is plotted as a...

  14. Differential soil respiration responses to changing hydrologic regimes

    Science.gov (United States)

    Vincent J. Pacific; Brian L. McGlynn; Diego A. Riveros-Iregui; Howard E. Epstein; Daniel L. Welsch

    2009-01-01

    Soil respiration is tightly coupled to the hydrologic cycle (i.e., snowmelt and precipitation timing and magnitude). We examined riparian and hillslope soil respiration across a wet (2005) and a dry (2006) growing season in a subalpine catchment. When comparing the riparian zones, cumulative CO2 efflux was 33% higher, and peak efflux occurred 17 days earlier during the...

  15. Automatic patient respiration failure detection system with wireless transmission

    Science.gov (United States)

    Dimeff, J.; Pope, J. M.

    1968-01-01

    Automatic respiration failure detection system detects respiration failure in patients with a surgically implanted tracheostomy tube, and actuates an audible and/or visual alarm. The system incorporates a miniature radio transmitter so that the patient is unencumbered by wires yet can be monitored from a remote location.

  16. Soil respiration response to experimental disturbances over 3 years

    Science.gov (United States)

    Amy Concilio; Siyan Ma; Soung-Ryoul Ryu; Malcolm North; Jiquan Chen

    2006-01-01

    Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixed-conifer forest on the western slope of the Sierra Nevada Mountains. Experimental treatments...

  17. Respirators: Air Purifying, Self-Study, Course 40723

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-12-21

    Respirators: Air Purifying Self-Study (COURSE 40723) is designed for Los Alamos National Laboratory (LANL) workers, support services subcontractors, and other LANL subcontractors who work under the LANL Respiratory Protection Program (RPP). This course also meets the air-purifying respirators (APRs) retraining requirement.

  18. Soil Respiration and Student Inquiry: A Perfect Match

    Science.gov (United States)

    Hoyt, Catherine Marie; Wallenstein, Matthew David

    2011-01-01

    This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…

  19. Redox Fluctuations Increase the Contribution of Lignin to Soil Respiration

    Science.gov (United States)

    Hall, S. J.; Silver, W. L.; Timokhin, V.; Hammel, K.

    2014-12-01

    Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia has long been thought to suppress lignin decomposition, yet variation in oxygen (O2) availability in surface soils accompanying moisture fluctuations could potentially stimulate this process by generating reactive oxygen species via coupled biotic and abiotic iron (Fe) redox cycling. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical forest soils during ten-week laboratory incubations. We used synthetic lignins labeled with 13C in either of two positions (aromatic methoxyl and propyl Cβ) to provide highly sensitive and specific measures of lignin mineralization not previously employed in soils. Four-day redox fluctuations increased the percent contribution of methoxyl C to soil respiration, and cumulative methoxyl C mineralization was equivalent under static aerobic and fluctuating redox conditions despite lower total C mineralization in the latter treatment. Contributions of the highly stable Cβ to mineralization were also equivalent in static aerobic and fluctuating redox treatments during periods of O2 exposure, and nearly doubled in the fluctuating treatment after normalizing to cumulative O2 exposure. Oxygen fluctuations drove substantial net Fe reduction and oxidation, implying that reactive oxygen species generated during abiotic Fe oxidation likely contributed to the elevated contribution of lignin to C mineralization. Iron redox cycling provides a mechanism for lignin breakdown in soils that experience conditions unfavorable for canonical lignin-degrading organisms, and provides a potential mechanism for lignin depletion in soil organic matter during late-stage decomposition. Thus, close couplings between soil moisture, redox fluctuations, and lignin breakdown provide potential a link between climate variability and

  20. Respirable dust measured downwind during rock dust application.

    Science.gov (United States)

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  1. A Global Database of Soil Respiration Data, Version 1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides a soil respiration data database (SRDB), a near-universal compendium of published soil respiration (RS) data. Soil respiration, the...

  2. A Global Database of Soil Respiration Data, Version 2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides an updated soil respiration database (SRDB), a near-universal compendium of published soil respiration (RS) data. Soil respiration,...

  3. Microbial metal reduction by members of the genus Shewanella: novel strategies for anaerobic respiration

    International Nuclear Information System (INIS)

    Dichristina, Thomas; Bates, David J.; Burns, Justin L.; Dale, Jason R.; Payne, Amanda N.

    2006-01-01

    Metal-reducing members of the genus Shewanella are important components of the microbial community residing in redox-stratified freshwater and marine environments. Metal-reducing gram-negative bacteria such as Shewanella, however, are presented with a unique physiological challenge: they are required to respire anaerobically on terminal electron acceptors which are either highly insoluble (Fe(III)- and Mn(IV)-oxides) and reduced to soluble end-products or highly soluble (U(VI) and Tc(VII)) and reduced to insoluble end-products. To overcome physiological problems associated with metal solubility, metal-respiring Shewanella are postulated to employ a variety of novel respiratory strategies not found in other gram-negative bacteria which respire on soluble electron acceptors such as O2, NO3 and SO4. The following chapter highlights the latest findings on the molecular mechanism of Fe(III), U(VI) and Tc(VII) reduction by Shewanella, with particular emphasis on electron transport chain physiology.

  4. Harnessing the respiration machinery for high-yield production of chemicals in metabolically engineered Lactococcus lactis

    DEFF Research Database (Denmark)

    Liu, Jianming; Wang, Zhihao; Kandasamy, Vijayalakshmi

    2017-01-01

    on metabolically engineered Lactococcus lactis strains to optimize the production of acetoin and (R,R)−2,3-butanediol (R-BDO). In the absence of an external electron acceptor, a surplus of two NADH per acetoin molecule is produced. We found that a fully activated respiration was able to efficiently regenerate NAD......+, and a high titer of 371 mM (32 g/L) of acetoin was obtained with a yield of 82% of the theoretical maximum. Subsequently, we extended the metabolic pathway from acetoin to R-BDO by introducing the butanediol dehydrogenase gene from Bacillus subtilis. Since one mole of NADH is consumed when acetoin...... is converted into R-BDO per mole, only the excess of NADH needs to be oxidized via respiration. Either by fine-tuning the respiration capacity or by using a dual-phase fermentation approach involving a switch from fully respiratory to non-respiratory conditions, we obtained 361 mM (32 g/L) R-BDO with a yield...

  5. Selection of non-Saccharomyces yeast strains for reducing alcohol levels in wine by sugar respiration.

    Science.gov (United States)

    Quirós, Manuel; Rojas, Virginia; Gonzalez, Ramon; Morales, Pilar

    2014-07-02

    Respiration of sugars by non-Saccharomyces yeasts has been recently proposed for lowering alcohol levels in wine. Development of industrial fermentation processes based on such an approach requires, amongst other steps, the identification of yeast strains which are able to grow and respire under the relatively harsh conditions found in grape must. This work describes the characterization of a collection of non-Saccharomyces yeast strains in order to identify candidate yeast strains for this specific application. It involved the estimation of respiratory quotient (RQ) values under aerated conditions, at low pH and high sugar concentrations, calculation of yields of ethanol and other relevant metabolites, and characterization of growth responses to the main stress factors found during the first stages of alcoholic fermentation. Physiological features of some strains of Metschnikowia pulcherrima or two species of Kluyveromyces, suggest they are suitable for lowering ethanol yields by respiration. The unsuitability of Saccharomyces cerevisiae strains for this purpose was not due to ethanol yields (under aerated conditions they are low enough for a significant reduction in final ethanol content), but to the high acetic acid yields under these growth conditions. According to results from controlled aeration fermentations with one strain of M. pulcherrima, design of an aeration regime allowing for lowering ethanol yields though preserving grape must components from excessive oxidation, would be conceivable. Copyright © 2014. Published by Elsevier B.V.

  6. Protein phosphorylation in isolated human adipocytes - Adrenergic control of the phosphorylation of hormone-sensitive lipase

    International Nuclear Information System (INIS)

    Smiley, R.M.; Paul, S.; Browning, M.D.; Leibel, R.L.; Hirsch, J.

    1990-01-01

    The effect of adrenergic agents on protein phosphorylation in human adipocytes was examined. Freshly isolated human fat cells were incubated with 32 PO 4 in order to label intracellular ATP, then treated with a variety of adrenergic and other pharmacologic agents. Treatment with the β-adrenergic agonist isoproterenol led to a significant increase in phosphate content of at least five protein bands (M r 52, 53, 63, 67, 84 kDa). The increase in phosphorylation was partially inhibited by the α-2 agonist clonidine. Epinephrine, a combined α and β agonist, was less effective at increasing phosphate content of the proteins than was isoproterenol. Neither insulin nor the α-1 agonist phenylephrine had any discernible effect on the pattern of protein phosphorylation. The 84 kDa phosphorylated peptide band appears to contain hormone-sensitive lipase, a key enzyme in the lipolytic pathway which is activated by phosphorylation. These results are somewhat different than previously reported results for rat adipocytes, and represent the first report of overall pattern and adrenergic modulation of protein phosphorylation in human adipocytes

  7. Regulated release of Ca2+ from respiring mitochondria by Ca2+/2H+ antiport.

    Science.gov (United States)

    Fiskum, G; Lehninger, A L

    1979-07-25

    Simultaneous measurements of oxygen consumption and transmembrane transport of Ca2+, H+, and phosphate show that the efflux of Ca2+ from respiring tightly coupled rat liver mitochondria takes place by an electroneutral Ca2+/2H+ antiport process that is ruthenium red-insensitive and that is regulated by the oxidation-reduction state of the mitochondrial pyridine nucleotides. When mitochondrial pyridine nucleotides are kept in a reduced steady state, the efflux of Ca2+ is inhibited; when they are in an oxidized state, Ca2+ efflux is activated. These processes were demonstrated by allowing phosphate-depleted mitochondria respiring on succinate in the presence of rotenone to take up Ca2+ from the medium. Upon subsequent addition of ruthenium red to block Ca2+ transport via the electrophoretic influx pathway, and acetoacetate, to bring mitochondrial pyridine nucleotides into the oxidized state, Ca2+ efflux and H+ influx ensued. The observed H+ influx/Ca2+ efflux ratio was close to the value 2.0 predicted for the operation of an electrically neutral Ca2+/2H+ antiport process.

  8. Exercise training in Tgαq*44 mice during the progression of chronic heart failure: cardiac vs. peripheral (soleus muscle) impairments to oxidative metabolism.

    Science.gov (United States)

    Grassi, Bruno; Majerczak, Joanna; Bardi, Eleonora; Buso, Alessia; Comelli, Marina; Chlopicki, Stefan; Guzik, Magdalena; Mavelli, Irene; Nieckarz, Zenon; Salvadego, Desy; Tyrankiewicz, Urszula; Skórka, Tomasz; Bottinelli, Roberto; Zoladz, Jerzy A; Pellegrino, Maria Antonietta

    2017-08-01

    Cardiac function, skeletal (soleus) muscle oxidative metabolism, and the effects of exercise training were evaluated in a transgenic murine model (Tgα q *44) of chronic heart failure during the critical period between the occurrence of an impairment of cardiac function and the stage at which overt cardiac failure ensues (i.e., from 10 to 12 mo of age). Forty-eight Tgα q *44 mice and 43 wild-type FVB controls were randomly assigned to control groups and to groups undergoing 2 mo of intense exercise training (spontaneous running on an instrumented wheel). In mice evaluated at the beginning and at the end of training we determined: exercise performance (mean distance covered daily on the wheel); cardiac function in vivo (by magnetic resonance imaging); soleus mitochondrial respiration ex vivo (by high-resolution respirometry); muscle phenotype [myosin heavy chain (MHC) isoform content; citrate synthase (CS) activity]; and variables related to the energy status of muscle fibers [ratio of phosphorylated 5'-AMP-activated protein kinase (AMPK) to unphosphorylated AMPK] and mitochondrial biogenesis and function [peroxisome proliferative-activated receptor-γ coactivator-α (PGC-1α)]. In the untrained Tgα q *44 mice functional impairments of exercise performance, cardiac function, and soleus muscle mitochondrial respiration were observed. The impairment of mitochondrial respiration was related to the function of complex I of the respiratory chain, and it was not associated with differences in CS activity, MHC isoforms, p-AMPK/AMPK, and PGC-1α levels. Exercise training improved exercise performance and cardiac function, but it did not affect mitochondrial respiration, even in the presence of an increased percentage of type 1 MHC isoforms. Factors "upstream" of mitochondria were likely mainly responsible for the improved exercise performance. NEW & NOTEWORTHY Functional impairments in exercise performance, cardiac function, and soleus muscle mitochondrial respiration

  9. Tyrosine phosphorylation of dihydrolipoamide dehydrogenase as a potential cadmium target and its inhibitory role in regulating mouse sperm motility.

    Science.gov (United States)

    Li, Xinhong; Wang, Lirui; Li, Yuhua; Fu, Jieli; Zhen, Linqing; Yang, Qiangzhen; Li, Sisi; Zhang, Yukun

    2016-05-16

    Cadmium (Cd) is reported to reduce sperm motility and functions. However, the molecular mechanisms of Cd-induced toxicity remain largely unknown, presenting a major knowledge gap in research on reproductive toxicology. In the present study, we identified a candidate protein, dihydrolipoamide dehydrogenase (DLD), which is a post-pyruvate metabolic enzyme, exhibiting tyrosine phosphorylation in mouse sperm exposed to Cd both in vivo and in vitro. Immunoprecipitation assay demonstrated DLD was phosphorylated in tyrosine residues without altered expression after Cd treatment, which further confirmed our identified result. However, the tyrosine phosphorylation of DLD did not participate in mouse sperm capacitation and Bovine Serum Albumin (BSA) effectively prevented the tyrosine phosphorylation of DLD. Moreover, Cd-induced tyrosine phosphorylation of DLD lowered its dehydrogenase activity and meanwhile, Nicotinamide Adenine Dinucleotide Hydrogen (NADH) content, Adenosine Triphosphate (ATP) production and sperm motility were all inhibited by Cd. Interestingly, when the tyrosine phosphorylation of DLD was blocked by BSA, the decrease of DLD activity, NADH and ATP content as well as sperm motility was also suppressed simultaneously. These results suggested that Cd-induced tyrosine phosphorylation of DLD inhibited its activity and thus suppressed the tricarboxylic acid (TCA) cycle, which resulted in the reduction of NADH and hence the ATP production generated through oxidative phosphorylation (OPHOXS). Taken together, our results revealed that Cd induced DLD tyrosine phosphorylation, in response to regulate TCA metabolic pathway, which reduced ATP levels and these negative effects led to decreased sperm motility. This study provided new understanding of the mechanisms contributing to the harmful effects of Cd on the motility and function of spermatozoa. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. [Effects of management regime on soil respiration from agroecosystems].

    Science.gov (United States)

    Chen, Shu-tao; Zhu, Da-wei; Niu, Chuan-po; Zou, Jian-wen; Wang, Chao; Sun, Wen-juan

    2009-10-15

    In order to examine the effects of management regime, such as nitrogen application and plowing method, on soil respiration from farmland, the static opaque chamber-gas chromatograph method was used to measure soil CO2 fluxes in situ. The field measurement was carried out for 5 growing seasons, which were the 2002-2003 wheat, 2003 maize and soybean, 2003-2004 wheat, 2004 maize and 2004-2005 wheat seasons. Our results showed that soil respiration increased in fertilizer-applied treatments compared with no fertilizer treatment after 3 times of fertilizer application on 9 November 2002, 14 February and 26 March 2003. And the most obvious increase appeared following the third fertilizer application. No significant difference in soil respiration was found among several fertilizer application treatments. The effect of plowing depth on soil respiration was contingent on preceding cropping practice. Over the 2003-2004 wheat-growing seasons (its preceding cropping practice was rice paddy), mean soil respiration rates were not significant different (p > 0.05) between no plowing treatment and shallow plowing treatment. The shallow plowing treatment CT2 led to higher soil CO2 losses compared with no plowing treatment of NT2 in the 2004 maize-growing season, however, the significant higher (p soil respiration rates occurred with no plowing treatment of NT3 in the following 2004-2005 wheat-growing season. Intensive plowing (25 cm depth), compared with no plowing practice (NT4), increased soil respiration significantly during the 2004-2005 wheat-growing season. Regression analysis showed that the exponential function could be employed to fit the relationship between soil respiration and temperature. The exponential relationship yielded the Q10 values which were varied from 1.26 to 3.60, with a mean value of 2.08. To evaluate the effect of temperature on soil respiration, the CO2 emission fluxes were normalized for each treatment and each crop growing season. Plotting the

  11. Flux control through protein phosphorylation in yeast

    DEFF Research Database (Denmark)

    Chen, Yu; Nielsen, Jens

    2016-01-01

    Protein phosphorylation is one of the most important mechanisms regulating metabolism as it can directly modify metabolic enzymes by the addition of phosphate groups. Attributed to such a rapid and reversible mechanism, cells can adjust metabolism rapidly in response to temporal changes. The yeast...... as well as identify mechanisms underlying human metabolic diseases. Here we collect functional phosphorylation events of 41 enzymes involved in yeast metabolism and demonstrate functional mechanisms and the application of this information in metabolic engineering. From a systems biology perspective, we...... describe the development of phosphoproteomics in yeast as well as approaches to analysing the phosphoproteomics data. Finally, we focus on integrated analyses with other omics data sets and genome-scale metabolic models. Despite the advances, future studies improving both experimental technologies...

  12. Solid polymer electrolyte from phosphorylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Fauzi, Iqbal, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Groups, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24

    Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component’s composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it’s characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensile resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10{sup −6} S/cm up to 6.01 × 10{sup −4} S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10{sup −3} S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications.

  13. Protein phosphorylation in bcterial signaling and regulation

    KAUST Repository

    Mijakovic, Ivan

    2016-01-26

    In 2003, it was demonstrated for the first time that bacteria possess protein-tyrosine kinases (BY-kinases), capable of phosphorylating other cellular proteins and regulating their activity. It soon became apparent that these kinases phosphorylate a number of protein substrates, involved in different cellular processes. More recently, we found out that BY-kinases can be activated by several distinct protein interactants, and are capable of engaging in cross-phosphorylation with other kinases. Evolutionary studies based on genome comparison indicate that BY-kinases exist only in bacteria. They are non-essential (present in about 40% bacterial genomes), and their knockouts lead to pleiotropic phenotypes, since they phosphorylate many substrates. Surprisingly, BY-kinase genes accumulate mutations at an increased rate (non-synonymous substitution rate significantly higher than other bacterial genes). One direct consequence of this phenomenon is no detectable co-evolution between kinases and their substrates. Their promiscuity towards substrates thus seems to be “hard-wired”, but why would bacteria maintain such promiscuous regulatory devices? One explanation is the maintenance of BY-kinases as rapidly evolving regulators, which can readily adopt new substrates when environmental changes impose selective pressure for quick evolution of new regulatory modules. Their role is clearly not to act as master regulators, dedicated to triggering a single response, but they might rather be employed to contribute to fine-tuning and improving robustness of various cellular responses. This unique feature makes BY-kinases a potentially useful tool in synthetic biology. While other bacterial kinases are very specific and their signaling pathways insulated, BY-kinase can relatively easily be engineered to adopt new substrates and control new biosynthetic processes. Since they are absent in humans, and regulate some key functions in pathogenic bacteria, they are also very promising

  14. Phosphorylation of proteins in Clostridium thermohydrosulfuricum

    International Nuclear Information System (INIS)

    Londesborough, J.

    1986-01-01

    Cell extracts of the thermophile Clostridium thermohydrosulfuricum catalyzed the phosphorylation by (γ- 32 P)ATP of several endogenous proteins with M/sub r/s between 13,000 and 100,000. Serine and tyrosine were the main acceptors. Distinct substrate proteins were found in the soluble (e.g., proteins p66, p63, and p53 of M/sub r/s 66,000, 63,000, and 53,000, respectively) and particulate (p76 and p30) fractions, both of which contained protein kinase and phosphatase activity. The soluble fraction suppressed the phosphorylation of particulate proteins and contained a protein kinase inhibitor. Phosphorylation of p53 was promoted by 10μM fructose 1,6-bisphosphate or glucose 1,6-bisphosphate and suppressed by hexose monophosphates, whereas p30 and p13 were suppressed by 5 μM brain (but not spinach) calmodulin. Polyamines, including the odd polyamines characteristic of thermophiles, modulated the labeling of most of the phosphoproteins. Apart from p66, all the proteins labeled in vitro were also rapidly labeled in intact cells by 32 P/sub i/. Several proteins strongly labeled in vivo were labeled slowly or not at all in vitro

  15. Root Zone Respiration on Hydroponically Grown Wheat Plant Systems

    Science.gov (United States)

    Soler-Crespo, R. A.; Monje, O. A.

    2010-01-01

    Root respiration is a biological phenomenon that controls plant growth and physiological development during a plant's lifespan. This process is dependent on the availability of oxygen in the system where the plant is located. In hydroponic systems, where plants are submerged in a solution containing vital nutrients but no type of soil, the availability of oxygen arises from the dissolved oxygen concentration in the solution. This oxygen concentration is dependent on the , gas-liquid interface formed on the upper surface of the liquid, as given by Henry's Law, depending on pressure and temperature conditions. Respiration rates of the plants rise as biomass and root zone increase with age. The respiration rate of Apogee wheat plants (Triticum aestivum) was measured as a function of light intensity (catalytic for photosynthesis) and CO2 concentration to determine their effect on respiration rates. To determine their effects on respiration rate and plant growth microbial communities were introduced into the system, by Innoculum. Surfactants were introduced, simulating gray-water usage in space, as another factor to determine their effect on chemical oxygen demand of microbials and on respiration rates of the plants. It is expected to see small effects from changes in CO2 concentration or light levels, and to see root respiration decrease in an exponential manner with plant age and microbial activity.

  16. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2.s(-1 and clipping (2.06 μmol.m(-2.s(-1 than under grazing (1.65 μmol.m-(2.s(-1 over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP. Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content and biotic (ANPP and BNPP factors regulate soil respiration in the semiarid temperate grassland of northern China.

  17. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Science.gov (United States)

    Wang, Zhen; Ji, Lei; Hou, Xiangyang; Schellenberg, Michael P

    2016-01-01

    Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2).s(-1)) and clipping (2.06 μmol.m(-2).s(-1)) than under grazing (1.65 μmol.m-(2).s(-1)) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.

  18. Temperature response of soil respiration largely unaltered with experimental warming

    Science.gov (United States)

    Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; Collins, Scott L.; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Steenberg Larsen, Klaus; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Penuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward B.; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

  19. The FOX transcription factor Hcm1 regulates oxidative metabolism in response to early nutrient limitation in yeast. Role of Snf1 and Tor1/Sch9 kinases.

    Science.gov (United States)

    Rodríguez-Colman, María José; Sorolla, M Alba; Vall-Llaura, Núria; Tamarit, Jordi; Ros, Joaquim; Cabiscol, Elisa

    2013-08-01

    Within Saccharomyces cerevisiae, Hcm1is a member of the forkhead transcription factor family with a role in chromosome organization. Our group recently described its involvement in mitochondrial biogenesis and stress resistance, and reports here that Hcm1 played a role in adaptation to respiratory metabolism when glucose or nitrogen was decreased. Regulation of Hcm1 activity occurs in at least three ways: i) protein quantity, ii) subcellular localization, and iii) transcriptional activity. Transcriptional activity was measured using a reporter gene fused to a promoter that contains a binding site for Hcm1. We also analyzed the levels of several genes whose expression is known to be regulated by Hcm1 levels and the role of the main kinases known to respond to nutrients. Lack of sucrose-nonfermenting (Snf1) kinase increases cytoplasmic localization of Hcm1, whereas Δtor1 cells showed a mild increase in nuclear Hcm1. In vitro experiments showed that Snf1 clearly phosphorylates Hcm1 while Sch9 exerts a milder phosphorylation. Although in vitroTor1 does not directly phosphorylate Hcm1, in vivo rapamycin treatment increases nuclear Hcm1. We conclude that Hcm1 participates in the adaptation of cells from fermentation to respiratory metabolism during nutrient scarcity. According to our hypothesis, when nutrient levels decrease, Snf1 phosphorylates Hcm1. This results in a shift from the cytoplasm to the nucleus and increased transcriptional activity of genes involved in respiration, use of alternative energy sources, NAD synthesis and oxidative stress resistance. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Data on effects of rotenone on calcium retention capacity, respiration and activities of respiratory chain complexes I and II in isolated rat brain mitochondria

    Directory of Open Access Journals (Sweden)

    Evelina Rekuviene

    2017-08-01

    Full Text Available The data presented in this article are related to the research article entitled “Rotenone decreases ischemia-induced injury by inhibiting mitochondrial permeability transition in mature brains” (Rekuviene et al., 2017 [1]. Data in this article present the direct effects of rotenone on calcium retention capacity (CRC in isolated normal cortex and cerebellum mitochondria, effects of rotenone intravenous infusion on leak and phosphorylating respiration rates of isolated cortex and cerebellum mitochondria, on activities of respiratory chain complexes I and II in freezed-thawed/sonicated cortex and cerebellum mitochondria after brain ischemia. In addition, detailed experimental procedures of isolation of brain mitochondria, measurements of CRC, respiration, activities of respiratory chain complexes and H2O2 generation in cortex and cerebellum mitochondria are described.

  1. Phenotypic and genotypic description of Sedimenticola selenatireducens strain CUZ, a marine (per)chlorate-respiring gammaproteobacterium, and its close relative the chlorate-respiring Sedimenticola strain NSS.

    Science.gov (United States)

    Carlström, Charlotte I; Loutey, Dana E; Wang, Ouwei; Engelbrektson, Anna; Clark, Iain; Lucas, Lauren N; Somasekhar, Pranav Y; Coates, John D

    2015-04-01

    Two (per)chlorate-reducing bacteria, strains CUZ and NSS, were isolated from marine sediments in Berkeley and San Diego, CA, respectively. Strain CUZ respired both perchlorate and chlorate [collectively designated (per)chlorate], while strain NSS respired only chlorate. Phylogenetic analysis classified both strains as close relatives of the gammaproteobacterium Sedimenticola selenatireducens. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) preparations showed the presence of rod-shaped, motile cells containing one polar flagellum. Optimum growth for strain CUZ was observed at 25 to 30 °C, pH 7, and 4% NaCl, while strain NSS grew optimally at 37 to 42 °C, pH 7.5 to 8, and 1.5 to 2.5% NaCl. Both strains oxidized hydrogen, sulfide, various organic acids, and aromatics, such as benzoate and phenylacetate, as electron donors coupled to oxygen, nitrate, and (per)chlorate or chlorate as electron acceptors. The draft genome of strain CUZ carried the requisite (per)chlorate reduction island (PRI) for (per)chlorate respiration, while that of strain NSS carried the composite chlorate reduction transposon responsible for chlorate metabolism. The PRI of strain CUZ encoded a perchlorate reductase (Pcr), which reduced both perchlorate and chlorate, while the genome of strain NSS included a gene for a distinct chlorate reductase (Clr) that reduced only chlorate. When both (per)chlorate and nitrate were present, (per)chlorate was preferentially utilized if the inoculum was pregrown on (per)chlorate. Historically, (per)chlorate-reducing bacteria (PRB) and chlorate-reducing bacteria (CRB) have been isolated primarily from freshwater, mesophilic environments. This study describes the isolation and characterization of two highly related marine halophiles, one a PRB and the other a CRB, and thus broadens the known phylogenetic and physiological diversity of these unusual metabolisms. Copyright © 2015, American Society for Microbiology. All Rights

  2. Oxygen and carbon isotopic compositions of gases respired by humans

    International Nuclear Information System (INIS)

    Epstein, S.; Zeiri, L.

    1988-01-01

    Oxygen-isotope fractionation associated with respiration in human individuals at rest is linearly related to the fraction of the O 2 utilized in the respiration process. The slope of this relationship is affected by a history of smoking, by vigorous exercise, and by the N 2 /O 2 ratio of the inhaled gas. For patients who suffer anemia-related diseases, the slope of this relationship is directly proportional to their level of hemoglobin. These results introduce a new approach for studying the mechanisms of O 2 consumption in human respiration and how they are affected by related diseases

  3. Controls on Ecosystem and Root Respiration in an Alaskan Peatland

    Science.gov (United States)

    McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

    2010-12-01

    Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised

  4. Herd protection effect of N95 respirators in healthcare workers.

    Science.gov (United States)

    Chen, Xin; Chughtai, Abrar Ahmad; MacIntyre, Chandini Raina

    2017-12-01

    Objective To determine if there was herd protection conferred to unprotected healthcare workers (HCWs) by N95 respirators worn by colleagues. Methods Data were analysed from a prospective cluster randomized clinical trial conducted in Beijing, China between 1 December 2008 and 15 January 2009. A minimum compliance level (MCL) of N95 respirators for prevention of clinical respiratory illness (CRI) was set based on various compliance cut-offs. The CRI rates were compared between compliant (≥MCL) and non-compliant (protection from use of N95 respirators by colleagues within a hospital ward.

  5. Estimating daytime ecosystem respiration from eddy-flux data

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Herbst, Mathias

    2011-01-01

    To understand what governs the patterns of net ecosystem exchange of CO2, an understanding of factors influencing the component fluxes, ecosystem respiration and gross primary production is needed. In the present paper, we introduce an alternative method for estimating daytime ecosystem respiration...... based on whole ecosystem fluxes from a linear regression of photosynthetic photon flux density data vs. daytime net ecosystem exchange data at forest ecosystem level. This method is based on the principles of the Kok-method applied at leaf level for estimating daytime respiration. We demonstrate...

  6. Respirator studies for the Nuclear Regulatory Commission (NRC)

    International Nuclear Information System (INIS)

    Skaggs, B.J.; Fairchild, C.I.; DeField, J.D.; Hack, A.L.

    1985-01-01

    A project of the Health, Safety and Environment Division is described. The project provides the NRC with information of respiratory protective devices and programs for their licensee personnel. The following activities were performed during FY 1983: selection of alternate test aerosols for quality assurance testing of high-efficiency particulate air respirator filters; evaluation of MAG-1 spectacles for use with positive and negative-pressure respirators; development of a Manual of Respiratory Protection in Emergencies Involving Airborne Radioactive Materials, and technical assistance to NRC licensees regarding respirator applications. 2 references, 1 figure

  7. Unraveling a phosphorylation event in a folded protein by NMR spectroscopy: phosphorylation of the Pin1 WW domain by PKA

    Energy Technology Data Exchange (ETDEWEB)

    Smet-Nocca, Caroline, E-mail: caroline.smet@univ-lille1.fr; Launay, Helene; Wieruszeski, Jean-Michel; Lippens, Guy; Landrieu, Isabelle, E-mail: isabelle.landrieu@univ-lille1.fr [Universite de Lille-Nord de France, Institut Federatif de Recherches 147, CNRS UMR 8576 (France)

    2013-04-15

    The Pin1 protein plays a critical role in the functional regulation of the hyperphosphorylated neuronal Tau protein in Alzheimer's disease and is by itself regulated by phosphorylation. We have used Nuclear Magnetic Resonance (NMR) spectroscopy to both identify the PKA phosphorylation site in the Pin1 WW domain and investigate the functional consequences of this phosphorylation. Detection and identification of phosphorylation on serine/threonine residues in a globular protein, while mostly occurring in solvent-exposed flexible loops, does not lead to chemical shift changes as obvious as in disordered proteins and hence does not necessarily shift the resonances outside the spectrum of the folded protein. Other complications were encountered to characterize the extent of the phosphorylation, as part of the {sup 1}H,{sup 15}N amide resonances around the phosphorylation site are specifically broadened in the unphosphorylated state. Despite these obstacles, NMR spectroscopy was an efficient tool to confirm phosphorylation on S16 of the WW domain and to quantify the level of phosphorylation. Based on this analytical characterization, we show that WW phosphorylation on S16 abolishes its binding capacity to a phosphorylated Tau peptide. A reduced conformational heterogeneity and flexibility of the phospho-binding loop upon S16 phosphorylation could account for part of the decreased affinity for its phosphorylated partner. Additionally, a structural model of the phospho-WW obtained by molecular dynamics simulation and energy minimization suggests that the phosphate moiety of phospho-S16 could compete with the phospho-substrate.

  8. Unraveling a phosphorylation event in a folded protein by NMR spectroscopy: phosphorylation of the Pin1 WW domain by PKA

    International Nuclear Information System (INIS)

    Smet-Nocca, Caroline; Launay, Hélène; Wieruszeski, Jean-Michel; Lippens, Guy; Landrieu, Isabelle

    2013-01-01

    The Pin1 protein plays a critical role in the functional regulation of the hyperphosphorylated neuronal Tau protein in Alzheimer’s disease and is by itself regulated by phosphorylation. We have used Nuclear Magnetic Resonance (NMR) spectroscopy to both identify the PKA phosphorylation site in the Pin1 WW domain and investigate the functional consequences of this phosphorylation. Detection and identification of phosphorylation on serine/threonine residues in a globular protein, while mostly occurring in solvent-exposed flexible loops, does not lead to chemical shift changes as obvious as in disordered proteins and hence does not necessarily shift the resonances outside the spectrum of the folded protein. Other complications were encountered to characterize the extent of the phosphorylation, as part of the 1 H, 15 N amide resonances around the phosphorylation site are specifically broadened in the unphosphorylated state. Despite these obstacles, NMR spectroscopy was an efficient tool to confirm phosphorylation on S16 of the WW domain and to quantify the level of phosphorylation. Based on this analytical characterization, we show that WW phosphorylation on S16 abolishes its binding capacity to a phosphorylated Tau peptide. A reduced conformational heterogeneity and flexibility of the phospho-binding loop upon S16 phosphorylation could account for part of the decreased affinity for its phosphorylated partner. Additionally, a structural model of the phospho-WW obtained by molecular dynamics simulation and energy minimization suggests that the phosphate moiety of phospho-S16 could compete with the phospho-substrate.

  9. Occupational Exposure to Respirable Dust, Respirable Crystalline Silica and Diesel Engine Exhaust Emissions in the London Tunnelling Environment.

    Science.gov (United States)

    Galea, Karen S; Mair, Craig; Alexander, Carla; de Vocht, Frank; van Tongeren, Martie

    2016-03-01

    Personal 8-h shift exposure to respirable dust, diesel engine exhaust emissions (DEEE) (as respirable elemental carbon), and respirable crystalline silica of workers involved in constructing an underground metro railway tunnel was assessed. Black carbon (BC) concentrations were also assessed using a MicroAeth AE51. During sprayed concrete lining (SCL) activities in the tunnel, the geometric mean (GM) respirable dust exposure level was 0.91mg m(-3), with the highest exposure measured on a back-up sprayer (3.20mg m(-3)). The GM respirable crystalline silica concentration for SCL workers was 0.03mg m(-3), with the highest measurement also for the back-up sprayer (0.24mg m(-3)). During tunnel boring machine (TBM) activities, the GM respirable dust concentration was 0.54mg m(-3). The GM respirable elemental carbon concentration for all the TBM operators was 18 µg m(-3); with the highest concentration measured on a segment lifter. The BC concentrations were higher in the SCL environment in comparison to the TBM environment (daily GM 18-54 µg m(-3) versus 3-6 µg m(-3)). This small-scale monitoring campaign provides additional personal data on exposures experienced by underground tunnel construction workers. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  10. Reactive Oxygen Species (ROS)-Activated ATM-Dependent Phosphorylation of Cytoplasmic Substrates Identified by Large-Scale Phosphoproteomics Screen*

    Science.gov (United States)

    Kozlov, Sergei V.; Waardenberg, Ashley J.; Engholm-Keller, Kasper; Arthur, Jonathan W.; Graham, Mark E.; Lavin, Martin

    2016-01-01

    Ataxia-telangiectasia, mutated (ATM) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signaling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoints, initiating DNA repair, and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here, we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach to identify cytoplasmic proteins altered in their phosphorylation state in control and ataxia-telangiectasia (A-T) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites, including 6,686 high-confidence sites mapping to 2,536 unique proteins. A total of 62 differentially phosphorylated peptides were identified; of these, 43 were phosphorylated in control but not in A-T cells, and 19 varied in their level of phosphorylation. Motif enrichment analysis of phosphopeptides revealed that consensus ATM serine glutamine sites were overrepresented. When considering phosphorylation events, only observed in control cells (not observed in A-T cells), with predicted ATM sites phosphoSerine/phosphoThreonine glutamine, we narrowed this list to 11 candidate ATM-dependent cytoplasmic proteins. Two of these 11 were previously described as ATM substrates (HMGA1 and UIMCI/RAP80), another five were identified in a whole cell extract phosphoproteomic screens, and the remaining four proteins had not been identified previously in DNA damage response screens. We validated the phosphorylation of three of these proteins (oxidative stress responsive 1 (OSR1), HDGF, and ccdc82) as ATM dependent after H2O2 exposure, and another protein (S100A11) demonstrated ATM

  11. Respiration in heterotrophic unicellular eukaryotic organisms.

    Science.gov (United States)

    Fenchel, Tom

    2014-08-01

    Surface:volume quotient, mitochondrial volume fraction, and their distribution within cells were investigated and oxygen gradients within and outside cells were modelled. Cell surface increases allometrically with cell size. Mitochondrial volume fraction is invariant with cell size and constitutes about 10% and mitochondria are predominantly found close to the outer membrane. The results predict that for small and medium sized protozoa maximum respiration rates should be proportional to cell volume (scaling exponent ≈1) and access to intracellular O2 is not limiting except at very low ambient O2-tensions. Available data do not contradict this and some evidence supports this interpretation. Cell size is ultimately limited because an increasing fraction of the mitochondria becomes exposed to near anoxic conditions with increasing cell size. The fact that mitochondria cluster close to the cell surface and the allometric change in cell shape with increasing cell size alleviates the limitation of aerobic life at low ambient O2-tension and for large cell size. Copyright © 2014 Elsevier GmbH. All rights reserved.

  12. Identification of the protein kinase C phosphorylation site in neuromodulin

    International Nuclear Information System (INIS)

    Apel, E.D.; Byford, M.F.; Au, D.; Walsh, K.A.; Storm, D.R.

    1990-01-01

    Neuromodulin (P-57, GAP-43, B-50, F-1) is a neurospecific calmodulin binding protein that is phosphorylated by protein kinase C. Phosphorylation by protein kinase C has been shown to abolish the affinity of neuromodulin for calmodulin and the authors have proposed that the concentration of free CaM in neurons may be regulated by phosphorylation and dephosphorylation of neuromodulin. The purpose of this study was to identify the protein kinase C phosphorylation site(s) in neuromodulin using recombinant neuromodulin as a substrate. Toward this end, it was demonstrated that recombinant neuromodulin purified from Escherichia coli and bovine neuromodulin were phosphorylated with similar K m values and stoichiometries and that protein kinase C mediated phosphorylation of both proteins abolished binding to calmodulin-Sepharose. Recombinant neuromodulin was phosphorylated by using protein kinase C and [γ- 32 P]ATP and digested with trypsin, and the resulting peptides were separated by HPLC. Only one 32 P-labeled tryptic peptide was generated from phosphorylated neuromodulin. They conclude that serine-41 is the protein kinase C phosphorylation site of neuromodulin and that phosphorylation of this amino acid residue blocks binding of calmoculin to neuromodulin. The proximity of serine-41 to the calmodulin binding domain in neuromodulin very likely explains the effect of phosphorylation on the affinity of neuromodulin for calmodulin

  13. Obesity-Linked Phosphorylation of SIRT1 by Casein Kinase 2 Inhibits Its Nuclear Localization and Promotes Fatty Liver.

    Science.gov (United States)

    Choi, Sung E; Kwon, Sanghoon; Seok, Sunmi; Xiao, Zhen; Lee, Kwan-Woo; Kang, Yup; Li, Xiaoling; Shinoda, Kosaku; Kajimura, Shingo; Kemper, Byron; Kemper, Jongsook Kim

    2017-08-01

    Sirtuin1 (SIRT1) deacetylase delays and improves many obesity-related diseases, including nonalcoholic fatty liver disease (NAFLD) and diabetes, and has received great attention as a drug target. SIRT1 function is aberrantly low in obesity, so understanding the underlying mechanisms is important for drug development. Here, we show that obesity-linked phosphorylation of SIRT1 inhibits its function and promotes pathological symptoms of NAFLD. In proteomic analysis, Ser-164 was identified as a major serine phosphorylation site in SIRT1 in obese, but not lean, mice, and this phosphorylation was catalyzed by casein kinase 2 (CK2), the levels of which were dramatically elevated in obesity. Mechanistically, phosphorylation of SIRT1 at Ser-164 substantially inhibited its nuclear localization and modestly affected its deacetylase activity. Adenovirus-mediated liver-specific expression of SIRT1 or a phosphor-defective S164A-SIRT1 mutant promoted fatty acid oxidation and ameliorated liver steatosis and glucose intolerance in diet-induced obese mice, but these beneficial effects were not observed in mice expressing a phosphor-mimic S164D-SIRT1 mutant. Remarkably, phosphorylated S164-SIRT1 and CK2 levels were also highly elevated in liver samples of NAFLD patients and correlated with disease severity. Thus, inhibition of phosphorylation of SIRT1 by CK2 may serve as a new therapeutic approach for treatment of NAFLD and other obesity-related diseases. Copyright © 2017 American Society for Microbiology.

  14. Contribution of root to soil respiration and carbon balance in ...

    Indian Academy of Sciences (India)

    PRAKASH

    improves our understanding of the terrestrial carbon cycle ... considerably lower net ecosystem productivity in Community 2 than in Community 1 .... soil respiration chambers for each time were dried at 31ºC ..... Using existing management.

  15. Characterization of respirable mine dust and diesel particulate matter

    CSIR Research Space (South Africa)

    Mahlangu, Vusi J

    2015-11-01

    Full Text Available This paper presents the preliminary outcomes to develop and optimize methods to characterize DPM and respirable dust samples for the following: Crystalline compounds Common mineral analyses Particle size distribution Elemental Carbon (EC...

  16. Redefinition and global estimation of basal ecosystem respiration rate

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenping [College of Global Change and Earth System Science, Beijing Normal University, Beijing, China; Luo, Yiqi [Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, USA; Li, Xianglan [College of Global Change and Earth System Science, Beijing Normal University, Beijing, China; Liu, Shuguang; Yu, Guirui [Key Laboratory of Ecosystem Network Observation and Modeling, Synthesis Research Center of Chinese Ecosystem Research Network, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; Zhou, Tao [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China; Bahn, Michael [Institute of Ecology, University of Innsbruck, Innsbruck, Austria; Black, Andy [Faculty of Land and Food Systems, University of British Columbia, Vancouver, B. C., Canada; Desai, Ankur R. [Atmospheric and Oceanic Sciences Department, Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA; Cescatti, Alessandro [Institute for Environment and Sustainability, Joint Research Centre, European Commission, Ispra, Italy; Marcolla, Barbara [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Jacobs, Cor [Alterra, Earth System Science-Climate Change, Wageningen University, Wageningen, Netherlands; Chen, Jiquan [Department of Earth, Ecological, and Environmental Sciences, University of Toledo, Toledo, Ohio, USA; Aurela, Mika [Climate and Global Change Research, Finnish Meteorological Institute, Helsinki, Finland; Bernhofer, Christian [Chair of Meteorology, Institute of Hydrology and Meteorology, Technische Universität Dresden, Dresden, Germany; Gielen, Bert [Department of Biology, University of Antwerp, Wilrijk, Belgium; Bohrer, Gil [Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, Columbus, Ohio, USA; Cook, David R. [Climate Research Section, Environmental Science Division, Argonne National Laboratory, Argonne, Illinois, USA; Dragoni, Danilo [Department of Geography, Indiana University, Bloomington, Indiana, USA; Dunn, Allison L. [Department of Physical and Earth Sciences, Worcester State College, Worcester, Massachusetts, USA; Gianelle, Damiano [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Grünwald, Thomas [Chair of Meteorology, Institute of Hydrology and Meteorology, Technische Universität Dresden, Dresden, Germany; Ibrom, Andreas [Risø DTU National Laboratory for Sustainable Energy, Biosystems Division, Technical University of Denmark, Roskilde, Denmark; Leclerc, Monique Y. [Department of Crop and Soil Sciences, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, Georgia, USA; Lindroth, Anders [Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, Sweden; Liu, Heping [Laboratory for Atmospheric Research, Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, USA; Marchesini, Luca Belelli [Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, Viterbo, Italy; Montagnani, Leonardo; Pita, Gabriel [Department of Mechanical Engineering, Instituto Superior Técnico, Lisbon, Portugal; Rodeghiero, Mirco [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Rodrigues, Abel [Unidade de Silvicultura e Produtos Florestais, Instituto Nacional dos Recursos Biológicos, Oeiras, Portugal; Starr, Gregory [Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA; Stoy, Paul C. [Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA

    2011-10-13

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located at latitudes ranging from ~3°S to ~70°N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual

  17. Disclosure and Fit Capability of the Filtering Facepiece Respirator.

    Science.gov (United States)

    Lofgren, Don J

    2018-05-01

    The filtering facepiece air-purifying respirator is annually purchased in the tens of millions and widely used for worker protection from harmful airborne particulates. The workplace consumers of this safety product, i.e., employers, workers, and safety and health professionals, have assurances of its effectiveness through the respirator certification and disclosure requirements of the National Institute for Occupational Safety and Health. However, the certification of a critical performance requirement has been missing for the approved filtering facepiece respirator since 1995: fit capability. Without this certification, consumers continue to be at risk of purchasing a respirator model that may fit a small percentage of the intended users. This commentary updates and expands an earlier one by this author, addresses the consequences of poorly fitting certified models on the market and lack of disclosure, and calls for further action by National Institute for Occupational Safety and Health to meet the needs and expectations of the consumer.

  18. Temperature response of soil respiration largely unaltered with experimental warming

    DEFF Research Database (Denmark)

    Carey, Joanna C; Tang, Jianwu; Templer, Pamela H

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific...... attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies......, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation...

  19. respiration and transpiration characteristics of selected fresh fruits

    African Journals Online (AJOL)

    AISA

    were higher in optimal atmospheres. The Q10 values ... High respiration rates increase tissue aging and decrease the ability of the product to repel ... Two types of containers were used for the ..... availability of oxygen around the product also.

  20. Resveratrol Inhibition of Cellular Respiration: New Paradigm for an Old Mechanism

    Directory of Open Access Journals (Sweden)

    Luis Alberto Madrigal-Perez

    2016-03-01

    Full Text Available Resveratrol (3,4′,5-trihydroxy-trans-stilbene, RSV has emerged as an important molecule in the biomedical area. This is due to its antioxidant and health benefits exerted in mammals. Nonetheless, early studies have also demonstrated its toxic properties toward plant-pathogenic fungi of this phytochemical. Both effects appear to be opposed and caused by different molecular mechanisms. However, the inhibition of cellular respiration is a hypothesis that might explain both toxic and beneficial properties of resveratrol, since this phytochemical: (1 decreases the production of energy of plant-pathogenic organisms, which prevents their proliferation; (2 increases adenosine monophosphate/adenosine diphosphate (AMP/ADP ratio that can lead to AMP protein kinase (AMPK activation, which is related to its health effects, and (3 increases the reactive oxygen species generation by the inhibition of electron transport. This pro-oxidant effect induces expression of antioxidant enzymes as a mechanism to counteract oxidative stress. In this review, evidence is discussed that supports the hypothesis that cellular respiration is the main target of resveratrol.

  1. Tai Chi training reduced coupling between respiration and postural control.

    Science.gov (United States)

    Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

    2016-01-01

    In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body's center-of-mass including those caused by spontaneous respiration. Both aging and disease increase "posturo-respiratory synchronization;" which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86 ± 5 yrs) or educational-control program (n=34, 85 ± 6 yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (ppostural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part from optimization of this multi-system interaction. Copyright © 2015

  2. Carbon dioxide titration method for soil respiration measurements

    OpenAIRE

    Martín Rubio, Luis

    2017-01-01

    This thesis was commissioned by Tampere University of Applied Sciences, which was interested in studying and developing a titration measurement method for soil respiration and biodegradability. Some experiments were carried out measuring soil respiration for testing the method and others adding some biodegradable material like polylactic acid compressed material and 100% biodegradable plastic bags to test its biodegradability and the possibility to measure it via titration. The thesi...

  3. Fuzzy Control of Tidal volume, Respiration number and Pressure value

    OpenAIRE

    Hasan Guler; Fikret Ata

    2010-01-01

    In this study, control of tidal volume, respiration number and pressure value which are arrived to patient at mechanical ventilator device which is used in intensive care units were performed with fuzzy logic controller. The aim of this system is to reduce workload of aneshesiologist. By calculating tidal volume, respiration number and pressure value, the error Pe(k) between reference pressure value (Pref) and pressure of gas given ill person (Phasta) and error change rate ;#948;Pe(k) were co...

  4. Phosphoryl functionalized mesoporous silica for uranium adsorption

    International Nuclear Information System (INIS)

    Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun; Hongyu, Gong; Yujun, Zhang

    2017-01-01

    Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N_2 adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG"0, ΔH"0 and ΔS"0) confirmed that the adsorption process was endothermic and spontaneous.

  5. Phosphoryl functionalized mesoporous silica for uranium adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Hongyu, Gong, E-mail: gong_hongyu@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Yujun, Zhang, E-mail: yujunzhangcn@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2017-04-30

    Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N{sub 2} adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG{sup 0}, ΔH{sup 0} and ΔS{sup 0}) confirmed that the adsorption process was endothermic and spontaneous.

  6. Effect of mercuric ions on growth and respiration of two coagulase-positive Staphylococcus aureus strains

    Energy Technology Data Exchange (ETDEWEB)

    Tynecka, Z; Szymona, O

    1966-01-01

    Sensitivity toward HgCl/sub 2/ of two coagulase-positive Staphylococcus aureus strains has been studied. Strain 15 proved to be over 10 times more resistant to HgCl/sub 2/ in the growth test than strain 31. The former showed also higher rates of endogenous respiration and more actively oxidized glucose in presence of HgCl/sub 2/. Strain 31 grew better in absence of HgCl/sub 2/ but readily underwent inhibition both in the growth and glucose oxidation experiment. Strain 31 was, however, less sensitive to HgCl/sub 2/, as detected by methylene blue reduction in presence of malate and succinate as substrates. Cysteine largely reversed the inhibitory effect of mercuric ions. Experiments with radioactive Hg/sup 203/Cl/sub 2/ did not prove the sensitive strain 31 to bind more mercuric ions than strain 15. 12 references, 4 figures, 4 tables.

  7. Use of respirators for protection of workers against airborne radioactive materials

    International Nuclear Information System (INIS)

    Revoir, W.H.

    1990-01-01

    The various types of respirators and the requirements for an effective respirator program are outlined. The use of specific types of respirators to protect workers against inhalation of airborne radioactive materials is discussed. Problems encountered in using respirators in the nuclear industry which have resulted in worker injury and death are described

  8. Monitoring HPV-16 E7 phosphorylation events

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Marcela O.; Hošek, Tomáš; Calçada, Eduardo O.; Castiglia, Francesca [Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”, University of Florence, via Luigi Sacconi 6, Sesto Fiorentino (Italy); Massimi, Paola; Banks, Lawrence [International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Trieste (Italy); Felli, Isabella C., E-mail: felli@cerm.unifi.it [Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”, University of Florence, via Luigi Sacconi 6, Sesto Fiorentino (Italy); Pierattelli, Roberta, E-mail: pierattelli@cerm.unifi.it [Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”, University of Florence, via Luigi Sacconi 6, Sesto Fiorentino (Italy)

    2017-03-15

    HPV-16 E7 is one of the key proteins that, by interfering with the host metabolism through many protein-protein interactions, hijacks cell regulation and contributes to malignancy. Here we report the high resolution investigation of the CR3 region of HPV-16 E7, both as an isolated domain and in the full-length protein. This opens the way to the atomic level study of the many interactions in which HPV-16 E7 is involved. Along these lines we show here the effect of one of the key post-translational modifications of HPV-16 E7, the phosphorylation by casein kinase II.

  9. Stimulation of respiration in rat thymocytes induced by ionizing radiation

    International Nuclear Information System (INIS)

    Gudz, T.I.; Pandelova, I.G.; Novgorodov, S.A.

    1994-01-01

    The effect of X irradiation on the respiration of rat thymocytes was studied. An increase in the rate of O 2 uptake was observed 1 h after cells were irradiated with doses of 6-10 Gy. The radiation-induced increase in respiration could be blocked by oligomycin, an inhibitor of mitochondrial ATP synthase, suggesting control by increased cytoplasmic ATP turnover. The stimulation of respiration was not associated with changes in the activity of mitochondrial electron transfer enzymes or permeability of the inner membrane. Several inhibitors of processes which used ATP were screened for their effects on the basal respiration rate and on the radiation response. In irradiated thymocytes, an enhancement of inhibition of respiration by ouabain, La 3+ and cycloheximide was observed. These results indicate that the radiation-induced stimulation of respiration is due to changes in ion homeostasis and protein synthesis. The effect of X irradiation was shown to be independent of the redox status of nonprotein thiols and was not associated with detectable changes in some products of lipid peroxidation. The radiation-induced decrease in activity of superoxide dismutase suggests free radical involvement in deleterious effects of radiation. 43 refs., 2 figs., 3 tabs

  10. Quantitative evaluation of the protective effect of respirators

    International Nuclear Information System (INIS)

    Murata, Mikio

    1983-01-01

    The present status and related problems of the quantitative evaluation method for respirator efficiency are generally reviewed. As the introduction, the special features of various types of respirators are summarized, and the basic concept of leakage and the protection factor are explained. As for the quantitative measurement of the protective efficiency, the features of various existing man-test methods such as NaCl aerosol man-test, DOP (dioctyl phthalate) man-test, and SF 6 gas man-test are reviewed and discussed. As the important problems associated with those man-tests, the following aspects are discussed. The measurement of the aerosol concentration within masks; the calculation method for the protection factor; the effect of beards. The examples of measuring the protection factor are also explained for the following respirator systems: half mask respirator with a high efficiency filter; full face mask respirator with a high efficiency filter; demand mode and pressure-demand mode respirators; and mound suit with suspenders. Finally, the outline of the manual of respiratory protection published by NRC in 1976 is briefly reviewed. (Aoki, K.)

  11. Targeting mitochondrial respiration as a therapeutic strategy for cervical cancer.

    Science.gov (United States)

    Tian, Shenglan; Chen, Heng; Tan, Wei

    2018-05-23

    Targeting mitochondrial respiration has been documented as an effective therapeutic strategy in cancer. However, the impact of mitochondrial respiration inhibition on cervical cancer cells are not well elucidated. Using a panel of cervical cancer cell lines, we show that an existing drug atovaquone is active against the cervical cancer cells with high profiling of mitochondrial biogenesis. Atovaquone inhibited proliferation and induced apoptosis with varying efficacy among cervical cancer cell lines regardless of HPV infection, cellular origin and their sensitivity to paclitaxel. We further demonstrated that atovaquone acts on cervical cancer cells via inhibiting mitochondrial respiration. In particular, atovaquone specifically inhibited mitochondrial complex III but not I, II or IV activity, leading to respiration inhibition and energy crisis. Importantly, we found that the different sensitivity of cervical cancer cell lines to atovaquone were due to their differential level of mitochondrial biogenesis and dependency to mitochondrial respiration. In addition, we demonstrated that the in vitro observations were translatable to in vivo cervical cancer xenograft mouse model. Our findings suggest that the mitochondrial biogenesis varies among patients with cervical cancer. Our work also suggests that atovaquone is a useful addition to cervical cancer treatment, particularly to those with high dependency on mitochondrial respiration. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Two Proximal Skin Electrodes — A Respiration Rate Body Sensor

    Directory of Open Access Journals (Sweden)

    Viktor Avbelj

    2012-10-01

    Full Text Available We propose a new body sensor for extracting the respiration rate based on the amplitude changes in the body surface potential differences between two proximal body electrodes. The sensor could be designed as a plaster-like reusable unit that can be easily fixed onto the surface of the body. It could be equipped either with a sufficiently large memory for storing the measured data or with a low-power radio system that can transmit the measured data to a gateway for further processing. We explore the influence of the sensor’s position on the quality of the extracted results using multi-channel ECG measurements and considering all the pairs of two neighboring electrodes as potential respiration-rate sensors. The analysis of the clinical measurements, which also include reference thermistor-based respiration signals, shows that the proposed approach is a viable option for monitoring the respiration frequency and for a rough classification of breathing types. The obtained results were evaluated on a wireless prototype of a respiration body sensor. We indicate the best positions for the respiration body sensor and prove that a single sensor for body surface potential difference on proximal skin electrodes can be used for combined measurements of respiratory and cardiac activities.

  13. Improvement of ballistocardiogram processing by inclusion of respiration information

    International Nuclear Information System (INIS)

    Tavakolian, Kouhyar; Vaseghi, Ali; Kaminska, Bozena

    2008-01-01

    In this paper a novel methodology for processing of a ballistocardiogram (BCG) is proposed in which the respiration signal is utilized to improve the averaging of the BCG signal and ultimately the annotation and interpretation of the signal. Previous research works filtered out the respiration signal while the novelty of the current research is that, rather than removing the respiration effect from the signal, we utilize the respiration information to improve the averaging and thus analysis and interpretation of the BCG signal in diagnosis of cardiac malfunctions. This methodology is based on our investigation that BCG cycles corresponding to the inspiration and expiration phases of the respiration cycle are different in morphology. BCG cycles corresponding to the expiration phase of respiration have been proved to be more closely related to each other when compared to cycles corresponding to inspiration, and therefore expiration cycles are better candidates to be selected for the calculation of the averaged BCG signal. The new BCG average calculated based on this methodology is then considered as the representative and a template of the BCG signal for further processing. This template can be considered as the output of a clinical BCG instrument with higher reliability and accuracy compared to the previous processing methods

  14. The transcriptional co-repressor myeloid translocation gene 16 inhibits glycolysis and stimulates mitochondrial respiration.

    Directory of Open Access Journals (Sweden)

    Parveen Kumar

    Full Text Available The myeloid translocation gene 16 product MTG16 is found in multiple transcription factor-containing complexes as a regulator of gene expression implicated in development and tumorigenesis. A stable Tet-On system for doxycycline-dependent expression of MTG16 was established in B-lymphoblastoid Raji cells to unravel its molecular functions in transformed cells. A noticeable finding was that expression of certain genes involved in tumor cell metabolism including 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 and 4 (PFKFB3 and PFKFB4, and pyruvate dehydrogenase kinase isoenzyme 1 (PDK1 was rapidly diminished when MTG16 was expressed. Furthermore, hypoxia-stimulated production of PFKFB3, PFKFB4 and PDK1 was inhibited by MTG16 expression. The genes in question encode key regulators of glycolysis and its coupling to mitochondrial metabolism and are commonly found to be overexpressed in transformed cells. The MTG16 Nervy Homology Region 2 (NHR2 oligomerization domain and the NHR3 protein-protein interaction domain were required intact for inhibition of PFKFB3, PFKFB4 and PDK1 expression to occur. Expression of MTG16 reduced glycolytic metabolism while mitochondrial respiration and formation of reactive oxygen species increased. The metabolic changes were paralleled by increased phosphorylation of mitogen-activated protein kinases, reduced levels of amino acids and inhibition of proliferation with a decreased fraction of cells in S-phase. Overall, our findings show that MTG16 can serve as a brake on glycolysis, a stimulator of mitochondrial respiration and an inhibitor of cell proliferation. Hence, elevation of MTG16 might have anti-tumor effect.

  15. SH3 domain tyrosine phosphorylation--sites, role and evolution.

    Directory of Open Access Journals (Sweden)

    Zuzana Tatárová

    Full Text Available BACKGROUND: SH3 domains are eukaryotic protein domains that participate in a plethora of cellular processes including signal transduction, proliferation, and cellular movement. Several studies indicate that tyrosine phosphorylation could play a significant role in the regulation of SH3 domains. RESULTS: To explore the incidence of the tyrosine phosphorylation within SH3 domains we queried the PhosphoSite Plus database of phosphorylation sites. Over 100 tyrosine phosphorylations occurring on 20 different SH3 domain positions were identified. The tyrosine corresponding to c-Src Tyr-90 was by far the most frequently identified SH3 domain phosphorylation site. A comparison of sequences around this tyrosine led to delineation of a preferred sequence motif ALYD(Y/F. This motif is present in about 15% of human SH3 domains and is structurally well conserved. We further observed that tyrosine phosphorylation is more abundant than serine or threonine phosphorylation within SH3 domains and other adaptor domains, such as SH2 or WW domains. Tyrosine phosphorylation could represent an important regulatory mechanism of adaptor domains. CONCLUSIONS: While tyrosine phosphorylation typically promotes signaling protein interactions via SH2 or PTB domains, its role in SH3 domains is the opposite - it blocks or prevents interactions. The regulatory function of tyrosine phosphorylation is most likely achieved by the phosphate moiety and its charge interfering with binding of polyproline helices of SH3 domain interacting partners.

  16. Systematic inference of functional phosphorylation events in yeast metabolism.

    Science.gov (United States)

    Chen, Yu; Wang, Yonghong; Nielsen, Jens

    2017-07-01

    Protein phosphorylation is a post-translational modification that affects proteins by changing their structure and conformation in a rapid and reversible way, and it is an important mechanism for metabolic regulation in cells. Phosphoproteomics enables high-throughput identification of phosphorylation events on metabolic enzymes, but identifying functional phosphorylation events still requires more detailed biochemical characterization. Therefore, development of computational methods for investigating unknown functions of a large number of phosphorylation events identified by phosphoproteomics has received increased attention. We developed a mathematical framework that describes the relationship between phosphorylation level of a metabolic enzyme and the corresponding flux through the enzyme. Using this framework, it is possible to quantitatively estimate contribution of phosphorylation events to flux changes. We showed that phosphorylation regulation analysis, combined with a systematic workflow and correlation analysis, can be used for inference of functional phosphorylation events in steady and dynamic conditions, respectively. Using this analysis, we assigned functionality to phosphorylation events of 17 metabolic enzymes in the yeast Saccharomyces cerevisiae , among which 10 are novel. Phosphorylation regulation analysis cannot only be extended for inference of other functional post-translational modifications but also be a promising scaffold for multi-omics data integration in systems biology. Matlab codes for flux balance analysis in this study are available in Supplementary material. yhwang@ecust.edu.cn or nielsenj@chalmers.se. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  17. Phosphorylation status of pyruvate dehydrogenase distinguishes metabolic phenotypes of cultured rat brain astrocytes and neurons.

    Science.gov (United States)

    Halim, Nader D; Mcfate, Thomas; Mohyeldin, Ahmed; Okagaki, Peter; Korotchkina, Lioubov G; Patel, Mulchand S; Jeoung, Nam Ho; Harris, Robert A; Schell, Michael J; Verma, Ajay

    2010-08-01

    Glucose metabolism in nervous tissue has been proposed to occur in a compartmentalized manner with astrocytes contributing largely to glycolysis and neurons being the primary site of glucose oxidation. However, mammalian astrocytes and neurons both contain mitochondria, and it remains unclear why in culture neurons oxidize glucose, lactate, and pyruvate to a much larger extent than astrocytes. The objective of this study was to determine whether pyruvate metabolism is differentially regulated in cultured neurons versus astrocytes. Expression of all components of the pyruvate dehydrogenase complex (PDC), the rate-limiting step for pyruvate entry into the Krebs cycle, was determined in cultured astrocytes and neurons. In addition, regulation of PDC enzymatic activity in the two cell types via protein phosphorylation was examined. We show that all components of the PDC are expressed in both cell types in culture, but that PDC activity is kept strongly inhibited in astrocytes through phosphorylation of the pyruvate dehydrogenase alpha subunit (PDH alpha). In contrast, neuronal PDC operates close to maximal levels with much lower levels of phosphorylated PDH alpha. Dephosphorylation of astrocytic PDH alpha restores PDC activity and lowers lactate production. Our findings suggest that the glucose metabolism of astrocytes and neurons may be far more flexible than previously believed. (c) 2010 Wiley-Liss, Inc.

  18. Phenobarbital Meets Phosphorylation of Nuclear Receptors.

    Science.gov (United States)

    Negishi, Masahiko

    2017-05-01

    Phenobarbital was the first therapeutic drug to be characterized for its induction of hepatic drug metabolism. Essentially at the same time, cytochrome P450, an enzyme that metabolizes drugs, was discovered. After nearly 50 years of investigation, the molecular target of phenobarbital induction has now been delineated to phosphorylation at threonine 38 of the constitutive androstane receptor (NR1I3), a member of the nuclear receptor superfamily. Determining this mechanism has provided us with the molecular basis to understand drug induction of drug metabolism and disposition. Threonine 38 is conserved as a phosphorylation motif in the majority of both mouse and human nuclear receptors, providing us with an opportunity to integrate diverse functions of nuclear receptors. Here, I review the works and accomplishments of my laboratory at the National Institutes of Health National Institute of Environmental Health Sciences and the future research directions of where our study of the constitutive androstane receptor might take us. U.S. Government work not protected by U.S. copyright.

  19. Regulation of cardiac C-protein phosphorylation

    International Nuclear Information System (INIS)

    Titus, F.L.

    1985-01-01

    Molecular mechanisms of cardiac sympathetic and parasympathetic responses were addressed by studying subcellular changes in protein phosphorylation, cAMP-dependent protein kinase activity and protein phosphatase activity in frog hearts. B-adrenergic agonists increased and muscarinic cholinergic agonists decreased [ 32 P]phosphate incorporation into C-protein, a thick filament component. Regulation of protein phosphatase activity by Iso and methacholine (MCh) was assayed using extracts of drug treated frog hearts and [ 32 P]phospho-C-protein as substrate. Total phosphatase activity decreased 21% in extracts from hearts perfused with 0.1 μM Iso and 17% in hearts exposed to Iso plus 1 μM methacholine. This decrease reflected decreased phosphatase-2A activity. No changes in total phosphatase activity were measurable in broken cells treated with Iso or MCh. The results suggest adrenergic stimulation changes contractile activity in frog hearts by activating cAMP-dependent protein kinase associated with particulate cellular elements and inactivating soluble protein phosphatase-2A. This is the first demonstration of coordinated regulation of these enzymes by B-adrenergic agonists favoring phosphorylation of effector proteins. Coordinated regulation by methacholine in the presence of Iso was not observed

  20. Components of Soil Respiration and its Monthly Dynamics in Rubber Plantation Ecosystems

    OpenAIRE

    Zhixiang Wu; Limin Guan; Bangqian Chen; Chuan Yang; Guoyu Lan; Guishui Xie; Zhaode Zhou

    2014-01-01

    Aim: Our objective was to quantify four components and study effect factors of soil respiration in rubber plantation ecosystems. Providing the basic data support for the establishment of the trade of rubber plantation ecosystem carbon source/sink. Methods: We used Li-6400 (IRGA, Li-COR) to quantitate four components of soil respiration in rubber plantation ecosystems at different ages. Soil respiration can be separated as four components: heterotrophic respiration (Rh), Respiration of roots (...

  1. Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates

    OpenAIRE

    Fendt, Sarah-Maria; Sauer, Uwe

    2010-01-01

    Abstract Background Depending on the carbon source, Saccharomyces cerevisiae displays various degrees of respiration. These range from complete respiration as in the case of ethanol, to almost complete fermentation, and thus very low degrees of respiration on glucose. While many key regulators are known for these extreme cases, we focus here on regulators that are relevant at intermediate levels of respiration. Results We address this question by linking the functional degree of respiration t...

  2. [Temperature sensitivity of wheat plant respiration and soil respiration influenced by increased UV-B radiation from elongation to flowering periods].

    Science.gov (United States)

    Chen, Shu-Tao; Hu, Zheng-Hua; Li, Han-Mao; Ji, Yu-Hong; Yang, Yan-Ping

    2009-05-15

    Field experiment was carried out in the spring of 2008 in order to investigate the effects of increased UV-B radiation on the temperature sensitivity of wheat plant respiration and soil respiration from elongation to flowering periods. Static chamber-gas chromatography method was used to measure ecosystem respiration and soil respiration under 20% UV-B radiation increase and control. Environmental factors such as temperature and moisture were also measured. Results indicated that supplemental UV-B radiation inhibited the ecosystem respiration and soil respiration from wheat elongation to flowering periods, and the inhibition effect was more obvious for soil respiration than for ecosystem respiration. Ecosystem respiration rates, on daily average, were 9%, 9%, 3%, 16% and 30% higher for control than for UV-B treatment forthe five measurement days, while soil respiration rates were 99%, 93%, 106%, 38% and 10% higher for control than for UV-B treatment. The Q10s (temperature sensitivity coefficients) for plant respiration under control and UV-B treatments were 1.79 and 1.59, respectively, while the Q10s for soil respiration were 1.38 and 1.76, respectively. The Q10s for ecosystem respiration were 1.65 and 1.63 under CK and UV-B treatments, respectively. Supplemental UV-B radiation caused a lower Q10 for plant respiration and a higher Q10 for soil respiration, although no significant effect of supplemental UV-B radiation on the Q10 for ecosystem respiration was found.

  3. Chemoselective synthesis and analysis of naturally occurring phosphorylated cysteine peptides

    Science.gov (United States)

    Bertran-Vicente, Jordi; Penkert, Martin; Nieto-Garcia, Olaia; Jeckelmann, Jean-Marc; Schmieder, Peter; Krause, Eberhard; Hackenberger, Christian P. R.

    2016-09-01

    In contrast to protein O-phosphorylation, studying the function of the less frequent N- and S-phosphorylation events have lagged behind because they have chemical features that prevent their manipulation through standard synthetic and analytical methods. Here we report on the development of a chemoselective synthetic method to phosphorylate Cys side-chains in unprotected peptides. This approach makes use of a reaction between nucleophilic phosphites and electrophilic disulfides accessible by standard methods. We achieve the stereochemically defined phosphorylation of a Cys residue and verify the modification using electron-transfer higher-energy dissociation (EThcD) mass spectrometry. To demonstrate the use of the approach in resolving biological questions, we identify an endogenous Cys phosphorylation site in IICBGlc, which is known to be involved in the carbohydrate uptake from the bacterial phosphotransferase system (PTS). This new chemical and analytical approach finally allows further investigating the functions and significance of Cys phosphorylation in a wide range of crucial cellular processes.

  4. Seasonality of temperate forest photosynthesis and daytime respiration.

    Science.gov (United States)

    Wehr, R; Munger, J W; McManus, J B; Nelson, D D; Zahniser, M S; Davidson, E A; Wofsy, S C; Saleska, S R

    2016-06-30

    Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night-the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

  5. Creating the Chemistry in Cellular Respiration Concept Inventory (CCRCI)

    Science.gov (United States)

    Forshee, Jay Lance, II

    Students at our institution report cellular respiration to be the most difficult concept they encounter in undergraduate biology, but why students find this difficult is unknown. Students may find cellular respiration difficult because there is a large amount of steps, or because there are persistent, long-lasting misconceptions and misunderstandings surrounding their knowledge of chemistry, which affect their performance on cellular respiration assessments. Most studies of cellular respiration focus on student macro understanding of the process related to breathing, and matter and energy. To date, no studies identify which chemistry concepts are most relevant to students' development of an understanding of the process of cellular respiration or have developed an assessment to measure student understanding of them. Following the Delphi method, the researchers conducted expert interviews with faculty members from four-year, masters-, and PhD-granting institutions who teach undergraduate general biology, and are experts in their respective fields of biology. From these interviews, researchers identified twelve chemistry concepts important to understanding cellular respiration and using surveys, these twelve concepts were refined into five (electron transfer, energy transfer, thermodynamics (law/conservation), chemical reactions, and gradients). The researchers then interviewed undergraduate introductory biology students at a large Midwestern university to identify their knowledge and misconceptions of the chemistry concepts that the faculty had identified previously as important. The CCRCI was developed using the five important chemistry concepts underlying cellular respiration. The final version of the CCRCI was administered to n=160 introductory biology students during the spring 2017 semester. Reliability of the CCRCI was evaluated using Cronbach's alpha (=.7) and split-half reliability (=.769), and validity of the instrument was assessed through content validity

  6. Analogies between respiration and a light-driven proton pump as sources of energy for active glutamate transport in Halobacterium halobium

    Science.gov (United States)

    Belliveau, J. W.; Lanyi, J. K.

    1977-01-01

    Halobacterium halobium is known to contain sheets of bacteriorhodopsin, a pigment which upon exposure to light undergoes cyclic protonation and deprotonation, resulting in net H(+) translocation. In this paper, experiments were conducted to test H. halobium cell envelope vesicles for respiration-induced glutamate uptake. It is shown that glutamate transport in H. halobium cell envelope vesicles can occur as a result of respiration, as well as light acting on bacteriorhodopsin. Glutamate transport can be energized by the oxidation of dimethyl phenylenediamine, and the properties of the transport system are entirely analogous to those observed with illumination as the source of energy. In the case of respiration-dependent glutamate transport, the transportation is also driven by a Na(+) gradient, thereby confirming the existence of a single glutamate transport system independent of the source of energy. The analogy observed is indirect evidence that the cytochrome oxidase of H. halobium functions as a H(+) pump.

  7. Phosphorylation of mouse serine racemase regulates D-serine synthesis

    DEFF Research Database (Denmark)

    Foltyn, Veronika N; Zehl, Martin; Dikopoltsev, Elena

    2010-01-01

    Serine racemase (SR) catalyses the synthesis of the transmitter/neuromodulator D-serine, which plays a major role in synaptic plasticity and N-methyl D-aspartate receptor neurotoxicity. We now report that SR is phosphorylated at Thr71 and Thr227 as revealed by mass spectrometric analysis and in v...... with a phosphorylation-deficient SR mutant indicate that Thr71 phosphorylation increases SR activity, suggesting a novel mechanism for regulating D-serine production....

  8. Varicocele Negatively Affects Sperm Mitochondrial Respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Albani, Denise; Coppola, Lamberto; Zara, Vincenzo

    2015-10-01

    To evaluate the effect of varicocele on oxidative stress, sperm mitochondrial respiratory efficiency, sperm morphology, and semen parameters. A total of 20 patients with varicocele and 20 normozoospermic subjects without varicocele (control group) were recruited from a medical center for reproductive biology. The levels of serum reactive oxygen metabolites and seminal lipid peroxides were assessed for both control and varicocele subjects. Sperm deoxyribonucleic acid fragmentation was measured by sperm chromatin dispersion test. Mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. In this study, varicocele patients were compared with men without varicoceles. Oxidative stress was observed in the serum and seminal fluid of varicocele patients. These patients showed an increase of 59% (P <.05) in serum reactive oxygen metabolites and a 3-fold increase in the level of sperm lipid peroxides. A parallel and significant increase (a 2-fold increase; P <.05) in the degree of sperm deoxyribonucleic acid fragmentation was also observed. Varicocele patients showed a 27% decrease (P <.05) in mitochondrial respiratory activity in comparison to the control group. A 32% increase (P <.05) in sperm midpiece defects and a 41% decrease (P <.05) in sperm concentration and motility were also observed. Men with varicocele have increased markers of oxidative stress and decreased mitochondrial respiratory activity. These results correlated with abnormalities in semen parameters. For morphology, these correlated with midpiece defects. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The in vivo phosphorylation sites of rat brain dynamin I

    DEFF Research Database (Denmark)

    Graham, Mark E; Anggono, Victor; Bache, Nicolai

    2007-01-01

    -824). To resolve the discrepancy and to better understand the biological roles of dynI phosphorylation, we undertook a systematic identification of all phosphorylation sites in rat brain nerve terminal dynI. Using phosphoamino acid analysis, exclusively phospho-serine residues were found. Thr(780) phosphorylation...... of their relative abundance and relative responses to depolarization. The multiple phospho-sites suggest subtle regulation of synaptic vesicle endocytosis by new protein kinases and new protein-protein interactions. The homologous dynI and dynIII phosphorylation indicates a high mechanistic similarity. The results...

  10. Altered phosphorylation of rhodopsin in retinal dystrophic Irish Setters

    International Nuclear Information System (INIS)

    Cunnick, J.; Takemoto, D.J.; Takemoto, L.J.

    1986-01-01

    The carboxyl-terminus of rhodopsin in retinal dystrophic (rd) Irish Setters is altered near a possible phosphorylation site. To determine if this alteration affects ATP-mediated phosphorylation they compared the phosphorylation of rhodopsin from rd affected Irish Setters and normal unaffected dogs. Retinas from 8-week-old Irish Setters were phosphorylated with γ- 32 P-ATP and separated on SDS-PAGE. Compared to unaffected normal retinas, equalized for rhodopsin content, phosphorylation of rd rhodopsin was drastically reduced. When rd retinas were mixed with normal dog retinas, phosphorylation of the latter was inhibited. Inhibition also occurred when bovine retinas were mixed with rd retinas. The rd-mediated inhibition of phosphorylation was prevented by including 1mM NaF in the reaction mixture. Likewise, 1mM NaF restored phosphorylation of rd rhodopsin to normal levels. Phosphopeptide maps of rd and normal rhodopsin were identical and indicated 5 phosphopeptides present in each. Results suggest that one cause of the depressed rd rhodopsin phosphorylation is an increased phosphatase activity

  11. Cisplatinum and Taxol Induce Different Patterns of p53 Phosphorylation

    Directory of Open Access Journals (Sweden)

    Giovanna Damia

    2001-01-01

    Full Text Available Posttranslational modifications of p53 induced by two widely used anticancer agents, cisplatinum (DDP and taxol were investigated in two human cancer cell lines. Although both drugs were able to induce phosphorylation at serine 20 (Ser20, only DDP treatment induced p53 phosphorylation at serine 15 (Ser15. Moreover, both drug treatments were able to increase p53 levels and consequently the transcription of waf1 and mdm-2 genes, although DDP treatment resulted in a stronger inducer of both genes. Using two ataxia telangiectasia mutated (ATM cell lines, the role of ATM in druginduced p53 phosphorylations was investigated. No differences in drug-induced p53 phosphorylation could be observed, indicating that ATM is not the kinase involved in these phosphorylation events. In addition, inhibition of DNA-dependent protein kinase activity by wortmannin did not abolish p53 phosphorylation at Ser15 and Ser20, again indicating that DNA-PK is unlikely to be the kinase involved. After both taxol and DDP treatments, an activation of hCHK2 was found and this is likely to be responsible for phosphorylation at Ser20. In contrast, only DDP was able to activate ATR, which is the candidate kinase for phosphorylation of Ser15 by this drug. This data clearly suggests that differential mechanisms are involved in phosphorylation and activation of p53 depending on the drug type.

  12. Tyrosine phosphorylation of Grb14 by Tie2

    Directory of Open Access Journals (Sweden)

    Dumont Daniel J

    2010-10-01

    Full Text Available Abstract Background Growth factor receptor bound (Grb proteins 7, 10 and 14 are a family of structurally related multi-domain adaptor proteins involved in a variety of biological processes. Grb7, 10 and 14 are known to become serine and/or threonine phosphorylated in response to growth factor (GF stimulation. Grb7 and 10 have also been shown to become tyrosine phosphorylated under certain conditions. Under experimental conditions Grb7 is tyrosine phosphorylated by the Tie2/Tie-2/Tek angiogenic receptor tyrosine kinase (RTK. Furthermore, Grb14 has also been shown to interact with Tie2, however tyrosine phosphorylation of this Grb family member has yet to be reported. Results Here we report for the first time tyrosine phosphorylation of Grb14. This phosphorylation requires a kinase competent Tie2 as well as intact tyrosines 1100 and 1106 (Y1100 and Y1106 on the receptor. Furthermore, a complete SH2 domain on Grb14 is required for Grb14 tyrosine phosphorylation by Tie2. Grb14 was also able to become tyrosine phosphorylated in primary endothelial cells when treated with a soluble and potent variant of the Tie2 ligand, cartilage oligomeric matrix protein (COMP Ang1. Conclusion Our results show that Grb14, like its family members Grb7 and Grb10, is able to be tyrosine phosphorylated. Furthermore, our data indicate a role for Grb14 in endothelial signaling downstream of the Tie2 receptor.

  13. Automatic respiration tracking for radiotherapy using optical 3D camera

    Science.gov (United States)

    Li, Tuotuo; Geng, Jason; Li, Shidong

    2013-03-01

    Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

  14. Exposure to inhalable, respirable, and ultrafine particles in welding fume.

    Science.gov (United States)

    Lehnert, Martin; Pesch, Beate; Lotz, Anne; Pelzer, Johannes; Kendzia, Benjamin; Gawrych, Katarzyna; Heinze, Evelyn; Van Gelder, Rainer; Punkenburg, Ewald; Weiss, Tobias; Mattenklott, Markus; Hahn, Jens-Uwe; Möhlmann, Carsten; Berges, Markus; Hartwig, Andrea; Brüning, Thomas

    2012-07-01

    This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m(-3) for inhalable and 1.29 mg m(-3) for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m(-3)). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements welding fume. Concentrations were mainly predicted by the welding process and were significantly higher when local exhaust ventilation (LEV) was inefficient or when welding was performed in confined spaces. Substitution of high-emission techniques like FCAW, efficient LEV, and using PAPRs where applicable can reduce exposure to welding fume. However, harmonizing the different exposure metrics for UFP (as particle counts) and for the respirable or inhalable fraction of the welding fume (expressed as their mass) remains challenging.

  15. Bundvands respiration i Kattegat og Bælthavet

    DEFF Research Database (Denmark)

    Hansen, Jørgen L. S.; Bendtsen, Jørgen

    Der findes generelt meget få direkte målinger af den pelagiske respiration, og det har ikke været muligt at finde repræsentative målinger af den pelagiske respiration for de åbne danske farvande. Her præsenteres et sæsonstudie af bundvandets respiration fra 5 stationer i et transekt gående fra det....... Temperaturfølsomheden af respirationsraten udtrykt som en Q10 var 3,01 ± 1.07 for alle forsøg og uafhængigt af om prøverne blev kølet eller opvarmet under inkubationerne. Den labile pulje af organisk stof blev bestemt og de observerede respirations rater svarede til specifikke kulstof omsætningsrater på mellem 0...... målbar reduktion i det partikulære materiale under inkubationerne, tyder overraskende på,at opløst organisk materiale (DOM) er den vigtigste kulstofkilde for bundvandet respiration....

  16. Anthelmintic drug ivermectin inhibits angiogenesis, growth and survival of glioblastoma through inducing mitochondrial dysfunction and oxidative stress

    International Nuclear Information System (INIS)

    Liu, Yingying; Fang, Shanshan; Sun, Qiushi; Liu, Bo

    2016-01-01

    Glioblastoma is one of the most vascular brain tumour and highly resistant to current therapy. Targeting both glioblastoma cells and angiogenesis may present an effective therapeutic strategy for glioblastoma. In our work, we show that an anthelmintic drug, ivermectin, is active against glioblastoma cells in vitro and in vivo, and also targets angiogenesis. Ivermectin significantly inhibits growth and anchorage-independent colony formation in U87 and T98G glioblastoma cells. It induces apoptosis in these cells through a caspase-dependent manner. Ivermectin significantly suppresses the growth of two independent glioblastoma xenograft mouse models. In addition, ivermectin effectively targets angiogenesis through inhibiting capillary network formation, proliferation and survival in human brain microvascular endothelial cell (HBMEC). Mechanistically, ivermectin decreases mitochondrial respiration, membrane potential, ATP levels and increases mitochondrial superoxide in U87, T98G and HBMEC cells exposed to ivermectin. The inhibitory effects of ivermectin are significantly reversed in mitochondria-deficient cells or cells treated with antioxidants, further confirming that ivermectin acts through mitochondrial respiration inhibition and induction of oxidative stress. Importantly, we show that ivermectin suppresses phosphorylation of Akt, mTOR and ribosomal S6 in glioblastoma and HBMEC cells, suggesting its inhibitory role in deactivating Akt/mTOR pathway. Altogether, our work demonstrates that ivermectin is a useful addition to the treatment armamentarium for glioblastoma. Our work also highlights the therapeutic value of targeting mitochondrial metabolism in glioblastoma. - Highlights: • Ivermectin is effective in glioblastoma cells in vitro and in vivo. • Ivermectin inhibits angiogenesis. • Ivermectin induces mitochondrial dysfunction and oxidative stress. • Ivermectin deactivates Akt/mTOR signaling pathway.

  17. Augmentation of aerobic respiration and mitochondrial biogenesis in skeletal muscle by hypoxia preconditioning with cobalt chloride

    International Nuclear Information System (INIS)

    Saxena, Saurabh; Shukla, Dhananjay; Bansal, Anju

    2012-01-01

    High altitude/hypoxia training is known to improve physical performance in athletes. Hypoxia induces hypoxia inducible factor-1 (HIF-1) and its downstream genes that facilitate hypoxia adaptation in muscle to increase physical performance. Cobalt chloride (CoCl 2 ), a hypoxia mimetic, stabilizes HIF-1, which otherwise is degraded in normoxic conditions. We studied the effects of hypoxia preconditioning by CoCl 2 supplementation on physical performance, glucose metabolism, and mitochondrial biogenesis using rodent model. The results showed significant increase in physical performance in cobalt supplemented rats without (two times) or with training (3.3 times) as compared to control animals. CoCl 2 supplementation in rats augmented the biological activities of enzymes of TCA cycle, glycolysis and cytochrome c oxidase (COX); and increased the expression of glucose transporter-1 (Glut-1) in muscle showing increased glucose metabolism by aerobic respiration. There was also an increase in mitochondrial biogenesis in skeletal muscle observed by increased mRNA expressions of mitochondrial biogenesis markers which was further confirmed by electron microscopy. Moreover, nitric oxide production increased in skeletal muscle in cobalt supplemented rats, which seems to be the major reason for peroxisome proliferator activated receptor-gamma coactivator-1α (PGC-1α) induction and mitochondrial biogenesis. Thus, in conclusion, we state that hypoxia preconditioning by CoCl 2 supplementation in rats increases mitochondrial biogenesis, glucose uptake and metabolism by aerobic respiration in skeletal muscle, which leads to increased physical performance. The significance of this study lies in understanding the molecular mechanism of hypoxia adaptation and improvement of work performance in normal as well as extreme conditions like hypoxia via hypoxia preconditioning. -- Highlights: ► We supplemented rats with CoCl 2 for 15 days along with training. ► CoCl 2 supplementation

  18. Endothelial cell respiration is affected by the oxygen tension during shear exposure: role of mitochondrial peroxynitrite.

    Science.gov (United States)

    Jones, Charles I; Han, Zhaosheng; Presley, Tennille; Varadharaj, Saradhadevi; Zweier, Jay L; Ilangovan, Govindasamy; Alevriadou, B Rita

    2008-07-01

    Cultured vascular endothelial cell (EC) exposure to steady laminar shear stress results in peroxynitrite (ONOO(-)) formation intramitochondrially and inactivation of the electron transport chain. We examined whether the "hyperoxic state" of 21% O(2), compared with more physiological O(2) tensions (Po(2)), increases the shear-induced nitric oxide (NO) synthesis and mitochondrial superoxide (O(2)(*-)) generation leading to ONOO(-) formation and suppression of respiration. Electron paramagnetic resonance oximetry was used to measure O(2) consumption rates of bovine aortic ECs sheared (10 dyn/cm(2), 30 min) at 5%, 10%, or 21% O(2) or left static at 5% or 21% O(2). Respiration was inhibited to a greater extent when ECs were sheared at 21% O(2) than at lower Po(2) or left static at different Po(2). Flow in the presence of an endothelial NO synthase (eNOS) inhibitor or a ONOO(-) scavenger abolished the inhibitory effect. EC transfection with an adenovirus that expresses manganese superoxide dismutase in mitochondria, and not a control virus, blocked the inhibitory effect. Intracellular and mitochondrial O(2)(*-) production was higher in ECs sheared at 21% than at 5% O(2), as determined by dihydroethidium and MitoSOX red fluorescence, respectively, and the latter was, at least in part, NO-dependent. Accumulation of NO metabolites in media of ECs sheared at 21% O(2) was modestly increased compared with ECs sheared at lower Po(2), suggesting that eNOS activity may be higher at 21% O(2). Hence, the hyperoxia of in vitro EC flow studies, via increased NO and mitochondrial O(2)(*-) production, leads to enhanced ONOO(-) formation intramitochondrially and suppression of respiration.

  19. A novel high-throughput assay for islet respiration reveals uncoupling of rodent and human islets.

    Directory of Open Access Journals (Sweden)

    Jakob D Wikstrom

    Full Text Available The pancreatic beta cell is unique in its response to nutrient by increased fuel oxidation. Recent studies have demonstrated that oxygen consumption rate (OCR may be a valuable predictor of islet quality and long term nutrient responsiveness. To date, high-throughput and user-friendly assays for islet respiration are lacking. The aim of this study was to develop such an assay and to examine bioenergetic efficiency of rodent and human islets.The XF24 respirometer platform was adapted to islets by the development of a 24-well plate specifically designed to confine islets. The islet plate generated data with low inter-well variability and enabled stable measurement of oxygen consumption for hours. The F1F0 ATP synthase blocker oligomycin was used to assess uncoupling while rotenone together with myxothiazol/antimycin was used to measure the level of non-mitochondrial respiration. The use of oligomycin in islets was validated by reversing its effect in the presence of the uncoupler FCCP. Respiratory leak averaged to 59% and 49% of basal OCR in islets from C57Bl6/J and FVB/N mice, respectively. In comparison, respiratory leak of INS-1 cells and C2C12 myotubes was measured to 38% and 23% respectively. Islets from a cohort of human donors showed a respiratory leak of 38%, significantly lower than mouse islets.The assay for islet respiration presented here provides a novel tool that can be used to study islet mitochondrial function in a relatively high-throughput manner. The data obtained in this study shows that rodent islets are less bioenergetically efficient than human islets as well as INS1 cells.

  20. A grammar inference approach for predicting kinase specific phosphorylation sites.

    Science.gov (United States)

    Datta, Sutapa; Mukhopadhyay, Subhasis

    2015-01-01

    Kinase mediated phosphorylation site detection is the key mechanism of post translational mechanism that plays an important role in regulating various cellular processes and phenotypes. Many diseases, like cancer are related with the signaling defects which are associated with protein phosphorylation. Characterizing the protein kinases and their substrates enhances our ability to understand the mechanism of protein phosphorylation and extends our knowledge of signaling network; thereby helping us to treat such diseases. Experimental methods for predicting phosphorylation sites are labour intensive and expensive. Also, manifold increase of protein sequences in the databanks over the years necessitates the improvement of high speed and accurate computational methods for predicting phosphorylation sites in protein sequences. Till date, a number of computational methods have been proposed by various researchers in predicting phosphorylation sites, but there remains much scope of improvement. In this communication, we present a simple and novel method based on Grammatical Inference (GI) approach to automate the prediction of kinase specific phosphorylation sites. In this regard, we have used a popular GI algorithm Alergia to infer Deterministic Stochastic Finite State Automata (DSFA) which equally represents the regular grammar corresponding to the phosphorylation sites. Extensive experiments on several datasets generated by us reveal that, our inferred grammar successfully predicts phosphorylation sites in a kinase specific manner. It performs significantly better when compared with the other existing phosphorylation site prediction methods. We have also compared our inferred DSFA with two other GI inference algorithms. The DSFA generated by our method performs superior which indicates that our method is robust and has a potential for predicting the phosphorylation sites in a kinase specific manner.

  1. A Grammar Inference Approach for Predicting Kinase Specific Phosphorylation Sites

    Science.gov (United States)

    Datta, Sutapa; Mukhopadhyay, Subhasis

    2015-01-01

    Kinase mediated phosphorylation site detection is the key mechanism of post translational mechanism that plays an important role in regulating various cellular processes and phenotypes. Many diseases, like cancer are related with the signaling defects which are associated with protein phosphorylation. Characterizing the protein kinases and their substrates enhances our ability to understand the mechanism of protein phosphorylation and extends our knowledge of signaling network; thereby helping us to treat such diseases. Experimental methods for predicting phosphorylation sites are labour intensive and expensive. Also, manifold increase of protein sequences in the databanks over the years necessitates the improvement of high speed and accurate computational methods for predicting phosphorylation sites in protein sequences. Till date, a number of computational methods have been proposed by various researchers in predicting phosphorylation sites, but there remains much scope of improvement. In this communication, we present a simple and novel method based on Grammatical Inference (GI) approach to automate the prediction of kinase specific phosphorylation sites. In this regard, we have used a popular GI algorithm Alergia to infer Deterministic Stochastic Finite State Automata (DSFA) which equally represents the regular grammar corresponding to the phosphorylation sites. Extensive experiments on several datasets generated by us reveal that, our inferred grammar successfully predicts phosphorylation sites in a kinase specific manner. It performs significantly better when compared with the other existing phosphorylation site prediction methods. We have also compared our inferred DSFA with two other GI inference algorithms. The DSFA generated by our method performs superior which indicates that our method is robust and has a potential for predicting the phosphorylation sites in a kinase specific manner. PMID:25886273

  2. Effect of Curcumin on Phosphorylation of AMPK and ACC in C2C12 Skeletal Muscle Cells

    Directory of Open Access Journals (Sweden)

    F Ghanbarzadeh

    2013-10-01

    Full Text Available Introduction: AMP activated protein kinase (AMPK as key regulators of cell metabolism, plays a major role in the activation of catabolic pathways, such as glucose transport and fatty acid oxidation. Thus, activation of this pathway can be used in the treatment of diabetes and metabolic syndrome. Many studied proposed the effectiveness of the polyphenols present in rhizomes of turmeric (curcumin on diabetes and its related complications. Therefore, this study investigated the effects of curcumin as an activator of AMPK pathway in C2C12 muscle cells. Methods: This study was done on C2C12 skeletal muscle cell line. The cells were classified into two distinct groups: first group was treated with 40µM curcumin and the second one with 0.1% DMSO as a negative control. The phosphorylated (AMPK and phosphorylated acetyl COA carboxylase (ACC were evaluated and compared by Western blotting technique. Results: intracellular phosphorylated AMPK protein content in Curcumin-treated group was 132.6% and ACC protein phosphorylated was 366.47%. Conclusion: This study showed that the levels of phosphorylated AMPK and ACC protein in cells treated with curcumin are higher than the negative control. Thus curcumin can be regarded as an activator of AMPK activity in these cells and can assist as a potential target for making anti diabetic medecine that has a synergistic activity with insulin.

  3. Amazing structure of respirasome: unveiling the secrets of cell respiration.

    Science.gov (United States)

    Guo, Runyu; Gu, Jinke; Wu, Meng; Yang, Maojun

    2016-12-01

    Respirasome, a huge molecular machine that carries out cellular respiration, has gained growing attention since its discovery, because respiration is the most indispensable biological process in almost all living creatures. The concept of respirasome has renewed our understanding of the respiratory chain organization, and most recently, the structure of respirasome solved by Yang's group from Tsinghua University (Gu et al. Nature 237(7622):639-643, 2016) firstly presented the detailed interactions within this huge molecular machine, and provided important information for drug design and screening. However, the study of cellular respiration went through a long history. Here, we briefly showed the detoured history of respiratory chain investigation, and then described the amazing structure of respirasome.

  4. The Path of Carbon in Photosynthesis VII. Respiration and Photosynthesis

    Science.gov (United States)

    Benson, A. A.; Calvin, M.

    1949-07-21

    The relationship of respiration to photosynthesis in barley seedling leaves and the algae, Chlorella and Scenedesmus, has been investigated using radioactive carbon dioxide and the techniques of paper chromatography and radioautography. The plants are allowed to photosynthesize normally for thirty seconds in c{sup 14}O{sub 2} after which they are allowed to respire in air or helium in the light or dark. Respiration of photosynthetic intermediates as evidenced by the appearance of labeled glutomic, isocitric, fumaric and succinic acids is slower in the light than in the dark. Labeled glycolic acid is observed in barley and algae. It disappears rapidly in the dark and is maintained and increased in quantity in the light in C0{sub 2}-free air.

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

    Science.gov (United States)

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

    1996-01-01

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

  6. The effect of facial expressions on respirators contact pressures.

    Science.gov (United States)

    Cai, Mang; Shen, Shengnan; Li, Hui

    2017-08-01

    This study investigated the effect of four typical facial expressions (calmness, happiness, sadness and surprise) on contact characteristics between an N95 filtering facepiece respirator and a headform. The respirator model comprised two layers (an inner layer and an outer layer) and a nose clip. The headform model was comprised of a skin layer, a fatty tissue layer embedded with eight muscles, and a skull layer. Four typical facial expressions were generated by the coordinated contraction of four facial muscles. After that, the distribution of the contact pressure on the headform, as well as the contact area, were calculated. Results demonstrated that the nasal clip could help make the respirator move closer to the nose bridge while causing facial discomfort. Moreover, contact areas varied with different facial expressions, and facial expressions significantly altered contact pressures at different key areas, which may result in leakage.

  7. PAK6 Phosphorylates 14-3-3γ to Regulate Steady State Phosphorylation of LRRK2

    Directory of Open Access Journals (Sweden)

    Laura Civiero

    2017-12-01

    Full Text Available Mutations in Leucine-rich repeat kinase 2 (LRRK2 are associated with Parkinson's disease (PD and, as such, LRRK2 is considered a promising therapeutic target for age-related neurodegeneration. Although the cellular functions of LRRK2 in health and disease are incompletely understood, robust evidence indicates that PD-associated mutations alter LRRK2 kinase and GTPase activities with consequent deregulation of the downstream signaling pathways. We have previously demonstrated that one LRRK2 binding partner is P21 (RAC1 Activated Kinase 6 (PAK6. Here, we interrogate the PAK6 interactome and find that PAK6 binds a subset of 14-3-3 proteins in a kinase dependent manner. Furthermore, PAK6 efficiently phosphorylates 14-3-3γ at Ser59 and this phosphorylation serves as a switch to dissociate the chaperone from client proteins including LRRK2, a well-established 14-3-3 binding partner. We found that 14-3-3γ phosphorylated by PAK6 is no longer competent to bind LRRK2 at phospho-Ser935, causing LRRK2 dephosphorylation. To address whether these interactions are relevant in a neuronal context, we demonstrate that a constitutively active form of PAK6 rescues the G2019S LRRK2-associated neurite shortening through phosphorylation of 14-3-3γ. Our results identify PAK6 as the kinase for 14-3-3γ and reveal a novel regulatory mechanism of 14-3-3/LRRK2 complex in the brain.

  8. Phosphorylated benzimedazoles. 8. Synthesis of phosphorylated with /sup 32/P benzimidazoles

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, A M; Matevosyan, G L; Zavlin, P M [Leningradskij Sel' skokhozyajstvennyj Inst. (USSR)

    1983-03-01

    Accessible methods of synthesis and identification of phosphorylated benzimidazoles with specific activity close to the maximum permissible with labelled /sup 32/P are developed. These methods permit to determine the permissible residual amounts of the above preparations in nutrition products and the maximum permissible amounts of growth regulators in different objects of the environment, because it is impossible to detect, for example, tri(1-benzimidazolido)phosphate with other physico-chemical methods with the existing concentration of 10/sup -9/%.

  9. AMPK-independent pathways regulate skeletal muscle fatty acid oxidation

    DEFF Research Database (Denmark)

    Dzamko, Nicolas; Schertzer, Jonathan D.; Ryall, James G.

    2008-01-01

    The activation of AMP-activated protein kinase (AMPK) and phosphorylation/inhibition of acetyl-CoA carboxylase 2 (ACC2) is believed to be the principal pathway regulating fatty acid oxidation. However, during exercise AMPK activity and ACC Ser-221 phosphorylation does not always correlate...... with rates of fatty acid oxidation. To address this issue we have investigated the requirement for skeletal muscle AMPK in controlling aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside (AICAR) and contraction-stimulated fatty acid oxidation utilizing transgenic mice expressing a muscle-specific kinase...... dead (KD) AMPK alpha2. In wild-type (WT) mice, AICAR and contraction increased AMPK alpha2 and alpha1 activities, the phosphorylation of ACC2 and rates of fatty acid oxidation while tending to reduce malonyl-CoA levels. Despite no activation of AMPK in KD mice, ACC2 phosphorylation was maintained...

  10. Caloric Restriction-Induced Extension of Chronological Lifespan Requires Intact Respiration in Budding Yeast.

    Science.gov (United States)

    Kwon, Young-Yon; Lee, Sung-Keun; Lee, Cheol-Koo

    2017-04-01

    Caloric restriction (CR) has been shown to extend lifespan and prevent cellular senescence in various species ranging from yeast to humans. Many effects of CR may contribute to extend lifespan. Specifically, CR prevents oxidative damage from reactive oxygen species (ROS) by enhancing mitochondrial function. In this study, we characterized 33 single electron transport chain (ETC) gene-deletion strains to identify CR-induced chronological lifespan (CLS) extension mechanisms. Interestingly, defects in 17 of these 33 ETC gene-deleted strains showed loss of both respiratory function and CR-induced CLS extension. On the contrary, the other 16 respiration-capable mutants showed increased CLS upon CR along with increased mitochondrial membrane potential (MMP) and intracellular adenosine triphosphate (ATP) levels, with decreased mitochondrial superoxide generation. We measured the same parameters in the 17 non-respiratory mutants upon CR. CR simultaneously increased MMP and mitochondrial superoxide generation without altering intracellular ATP levels. In conclusion, respiration is essential for CLS extension by CR and is important for balancing MMP, ROS, and ATP levels.

  11. Separation Options for Phosphorylated Osteopontin from Transgenic Microalgae Chlamydomonas reinhardtii

    Directory of Open Access Journals (Sweden)

    Ayswarya Ravi

    2018-02-01

    Full Text Available Correct folding and post-translational modifications are vital for therapeutic proteins to elicit their biological functions. Osteopontin (OPN, a bone regenerative protein present in a range of mammalian cells, is an acidic phosphoprotein with multiple potential phosphorylation sites. In this study, the ability of unicellular microalgae, Chlamydomonas reinhardtii, to produce phosphorylated recombinant OPN in its chloroplast is investigated. This study further explores the impact of phosphorylation and expression from a “plant-like” algae on separation of OPN. Chromatography resins ceramic hydroxyapatite (CHT and Gallium-immobilized metal affinity chromatography (Ga-IMAC were assessed for their binding specificity to phosphoproteins. Non-phosphorylated recombinant OPN expressed in E. coli was used to compare the specificity of interaction of the resins to phosphorylated OPN. We observed that CHT binds OPN by multimodal interactions and was better able to distinguish phosphorylated proteins in the presence of 250 mM NaCl. Ga-IMAC interaction with OPN was not selective to phosphorylation, irrespective of salt, as the resin bound OPN from both algal and bacterial sources. Anion exchange chromatography proved an efficient capture method to partially separate major phosphorylated host cell protein impurities such as Rubisco from OPN.

  12. Distribution pattern of histone H3 phosphorylation at serine 10

    Indian Academy of Sciences (India)

    We evaluated the pattern of H3 phosphorylation using immunodetection during mitosis and meiosis in both diploid and tetraploid genotypes of Brachiaria species. Results revealed differences in chromosome distribution of H3S10ph when mitosis and meiosis were compared. Whole chromosomes were phosphorylated ...

  13. Phosphorylation of eukaryotic aminoacyl-tRNA synthetases

    International Nuclear Information System (INIS)

    Pendergast, A.M.

    1986-01-01

    The phosphorylation of the highly purified aminoacyl-tRNA synthetase complex from rabbit reticulocytes was examined. The synthetase complex contained, in addition to eight aminoacyl-tRNA synthetases, three unidentified proteins and was free of endogenous protein kinase activity. Incubation of the complex with casein kinase I in the presence of ATP resulted in the phosphorylation of four synthetases, the glutamyl-, isoleucyl-, methionyl-, and lysyl-tRNA synthetases. Phosphorylation by casein kinase I altered binding to tRNA-Sepharose such that the phosphorylated complex eluted at 190 mM NaCl instead of the 275 mM salt observed for the nonphosphorylated form. Phosphorylation by casein kinase I resulted in a significant inhibition of aminoacylation with the four synthetases; the activities of the nonphosphorylated synthetases were unchanged. One of the unidentified proteins in the complex (M/sub r/ 37,000) was also an excellent substrate for casein kinase I. A comparison of the properties and two-dimensional phosphopeptide pattern of this protein with that of casein kinase I suggest that the 37,000 dalton protein in the synthetase complex is an inactive form of casein kinase I. Two other protein kinases were shown to phosphorylate aminoacyl-tRNA synthetases in the complex. The phosphorylation of threonyl-tRNA synthetase was also investigated. Five aminoacyl-tRNA synthetases in the high molecular weight complex were shown to be phosphorylated in rabbit reticulocytes following labeling with ( 32 P)orthophosphate

  14. Quantitative phosphoproteomics reveals widespread full phosphorylation site occupancy during mitosis

    DEFF Research Database (Denmark)

    Miller, Martin Lee; Brunak, Søren; Olsen, JV

    2010-01-01

    and phosphorylation sites were grouped according to their cell cycle kinetics and compared to publicly available messenger RNA microarray data. Most detected phosphorylation sites and more than 20% of all quantified proteins showed substantial regulation, mainly in mitotic cells. Kinase-motif analysis revealed global...

  15. Myosin light chain kinase phosphorylation in tracheal smooth muscle

    International Nuclear Information System (INIS)

    Stull, J.T.; Hsu, L.C.; Tansey, M.G.; Kamm, K.E.

    1990-01-01

    Purified myosin light chain kinase from smooth muscle is phosphorylated by cyclic AMP-dependent protein kinase, protein kinase C, and the multifunctional calmodulin-dependent protein kinase II. Because phosphorylation in a specific site (site A) by any one of these kinases desensitizes myosin light chain kinase to activation by Ca2+/calmodulin, kinase phosphorylation could play an important role in regulating smooth muscle contractility. This possibility was investigated in 32 P-labeled bovine tracheal smooth muscle. Treatment of tissues with carbachol, KCl, isoproterenol, or phorbol 12,13-dibutyrate increased the extent of kinase phosphorylation. Six primary phosphopeptides (A-F) of myosin light chain kinase were identified. Site A was phosphorylated to an appreciable extent only with carbachol or KCl, agents which contract tracheal smooth muscle. The extent of site A phosphorylation correlated to increases in the concentration of Ca2+/calmodulin required for activation. These results show that cyclic AMP-dependent protein kinase and protein kinase C do not affect smooth muscle contractility by phosphorylating site A in myosin light chain kinase. It is proposed that phosphorylation of myosin light chain kinase in site A in contracting tracheal smooth muscle may play a role in the reported desensitization of contractile elements to activation by Ca2+

  16. Novel Role of Src in Priming Pyk2 Phosphorylation.

    Directory of Open Access Journals (Sweden)

    Ming Zhao

    Full Text Available Proline-rich tyrosine kinase 2 (Pyk2 is a member of the focal adhesion kinase (FAK family of non-receptor tyrosine kinases and plays an important role in diverse cellular events downstream of the integrin-family of receptors, including cell migration, proliferation and survival. Here, we have identified a novel role for Src kinase in priming Pyk2 phosphorylation and subsequent activation upon cell attachment on the integrin-ligand fibronectin. By using complementary methods, we show that Src activity is indispensable for the initial Pyk2 phosphorylation on the Y402 site observed in response to cell attachment. In contrast, the initial fibronectin-induced autophosphorylation of FAK in the homologous Y397 site occurs in a Src-independent manner. We demonstrate that the SH2-domain of Src is required for Src binding to Pyk2 and for Pyk2 phosphorylation at sites Y402 and Y579. Moreover, Y402 phosphorylation is a prerequisite for the subsequent Y579 phosphorylation. While this initial phosphorylation of Pyk2 by Src is independent of Pyk2 kinase activity, subsequent autophosphorylation of Pyk2 in trans is required for full Pyk2 phosphorylation and activation. Collectively, our studies reveal a novel function of Src in priming Pyk2 (but not FAK phosphorylation and subsequent activation downstream of integrins, and shed light on the signaling events that regulate the function of Pyk2.

  17. Measurement of lung tumor motion using respiration-correlated CT

    International Nuclear Information System (INIS)

    Mageras, Gig S.; Pevsner, Alex; Yorke, Ellen D.; Rosenzweig, Kenneth E.; Ford, Eric C.; Hertanto, Agung; Larson, Steven M.; Lovelock, D. Michael; Erdi, Yusuf E.; Nehmeh, Sadek A.; Humm, John L.; Ling, C. Clifton

    2004-01-01

    Purpose: We investigate the characteristics of lung tumor motion measured with respiration-correlated computed tomography (RCCT) and examine the method's applicability to radiotherapy planning and treatment. Methods and materials: Six patients treated for non-small-cell lung carcinoma received a helical single-slice computed tomography (CT) scan with a slow couch movement (1 mm/s), while simultaneously respiration is recorded with an external position-sensitive monitor. Another 6 patients receive a 4-slice CT scan in a cine mode, in which sequential images are acquired for a complete respiratory cycle at each couch position while respiration is recorded. The images are retrospectively resorted into different respiration phases as measured with the external monitor (4-slice data) or patient surface displacement observed in the images (single-slice data). The gross tumor volume (GTV) in lung is delineated at one phase and serves as a visual guide for delineation at other phases. Interfractional GTV variation is estimated by scaling diaphragm position variations measured in gated radiographs at treatment with the ratio of GTV:diaphragm displacement observed in the RCCT data. Results: Seven out of 12 patients show GTV displacement with respiration of more than 1 cm, primarily in the superior-inferior (SI) direction; 2 patients show anterior-posterior displacement of more than 1 cm. In all cases, extremes in GTV position in the SI direction are consistent with externally measured extremes in respiration. Three patients show evidence of hysteresis in GTV motion, in which the tumor trajectory is displaced 0.2 to 0.5 cm anteriorly during expiration relative to inspiration. Significant (>1 cm) expansion of the GTV in the SI direction with respiration is observed in 1 patient. Estimated intrafractional GTV motion for gated treatment at end expiration is 0.6 cm or less in all cases; however; interfraction variation estimates (systematic plus random) are more than 1 cm in 3

  18. Personal exposure versus monitoring station data for respirable particles

    Energy Technology Data Exchange (ETDEWEB)

    Sega, K; Fugas, M

    1982-01-01

    Personal exposure to respirable particles of 12 subjects working at the same location, but living in various parts of Zagreb, was monitored for 7 consecutive days and compared with simultaneously obtained data from the outdoor network station nearest to subject's home. Although personal exposure is related to the outdoor pollution, other sources play a considerable role. Indoor exposure takes, on the average, more than 80% of the total time. The ratio between average personal exposure and respirable particle levels in the outdoor air decreases with the increased outdoor concentration (r = -0.93), indicating that this relationship might serve as a basis for a rough estimate of possible personal exposure.

  19. Light-enhanced oxygen respiration in benthic phototrophic communities

    DEFF Research Database (Denmark)

    Epping, EHG; Jørgensen, BB

    1996-01-01

    Two microelectrode studies demonstrate the effect of Light intensity and photosynthesis on areal oxygen respiration in a hypersaline mat at Guerrero Negro, Mexico, and in an intertidal sediment at Texel, The Netherlands. The hypersaline mat was studied in the laboratory at light intensities of 0...... the day at prevailing light intensities. A 1-dimensional diffusion-reaction model was used to estimate gross photosynthesis and oxygen respiration per volume of sediment, as well as the euphotic depth and the sediment-water interface concentration of oxygen. Areal gross photosynthesis ranged from 9...

  20. Effects of protein phosphorylation on color stability of ground meat.

    Science.gov (United States)

    Li, Meng; Li, Xin; Xin, Jianzeng; Li, Zheng; Li, Guixia; Zhang, Yan; Du, Manting; Shen, Qingwu W; Zhang, Dequan

    2017-03-15

    The influence of protein phosphorylation on meat color stability was investigated in this study. Phosphatase and protein kinase inhibitors were added to minced ovine Longissimus thoracis et lumborum (LTL) muscle to manipulate the global phosphorylation of sarcoplasmic proteins. The data obtained show that the rate and extent of pH decline, along with lactate accumulation in postmortem muscle, were related to protein phosphorylation. Analysis of meat color and the relative content of myoglobin redox forms revealed that meat color stability was inversely related to the phosphorylation of sarcoplasmic proteins. Thus, this study suggests that protein phosphorylation may be involved in meat color development by regulating glycolysis and the redox stability of myoglobin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Importance of tyrosine phosphorylation in receptor kinase complexes.

    Science.gov (United States)

    Macho, Alberto P; Lozano-Durán, Rosa; Zipfel, Cyril

    2015-05-01

    Tyrosine phosphorylation is an important post-translational modification that is known to regulate receptor kinase (RK)-mediated signaling in animals. Plant RKs are annotated as serine/threonine kinases, but recent work has revealed that tyrosine phosphorylation is also crucial for the activation of RK-mediated signaling in plants. These initial observations have paved the way for subsequent detailed studies on the mechanism of activation of plant RKs and the biological relevance of tyrosine phosphorylation for plant growth and immunity. In this Opinion article we review recent reports on the contribution of RK tyrosine phosphorylation in plant growth and immunity; we propose that tyrosine phosphorylation plays a major regulatory role in the initiation and transduction of RK-mediated signaling in plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Phosphorylation of the Epstein-Barr virus nuclear antigen 2

    DEFF Research Database (Denmark)

    Grässer, F A; Göttel, S; Haiss, P

    1992-01-01

    A major in vivo phosphorylation site of the Epstein-Barr virus nuclear antigen 2 (EBNA-2) was found to be localized at the C-terminus of the protein. In vitro phosphorylation studies using casein kinase 1 (CK-1) and casein kinase 2 (CK-2) revealed that EBNA-2 is a substrate for CK-2, but not for CK......-1. The CK-2 specific phosphorylation site was localized in the 140 C-terminal amino acids using a recombinant trpE-C-terminal fusion protein. In a similar experiment, the 58 N-terminal amino acids expressed as a recombinant trpE-fusion protein were not phosphorylated. Phosphorylation of a synthetic...

  3. Sequential phosphorylation of GRASP65 during mitotic Golgi disassembly

    Directory of Open Access Journals (Sweden)

    Danming Tang

    2012-09-01

    GRASP65 phosphorylation during mitosis and dephosphorylation after mitosis are required for Golgi disassembly and reassembly during the cell cycle. At least eight phosphorylation sites on GRASP65 have been identified, but whether they are modified in a coordinated fashion during mitosis is so far unknown. In this study, we raised phospho-specific antibodies that recognize phosphorylated T220/T224, S277 and S376 residues of GRASP65, respectively. Biochemical analysis showed that cdc2 phosphorylates all three sites, while plk1 enhances the phosphorylation. Microscopic studies using these antibodies for double and triple labeling demonstrate sequential phosphorylation and dephosphorylation during the cell cycle. S277 and S376 are phosphorylated from late G2 phase through metaphase until telophase when the new Golgi is reassembled. T220/224 is not modified until prophase, but is highly modified from prometaphase to anaphase. In metaphase, phospho-T220/224 signal localizes on both Golgi haze and mitotic Golgi clusters that represent dispersed Golgi vesicles and Golgi remnants, respectively, while phospho-S277 and S376 labeling is more concentrated on mitotic Golgi clusters. Expression of a phosphorylation-resistant GRASP65 mutant T220A/T224A inhibited mitotic Golgi fragmentation to a much larger extent than the expression of the S277A and S376A mutants. In cytokinesis, T220/224 dephosphorylation occurs prior to that of S277, but after S376. This study provides evidence that GRASP65 is sequentially phosphorylated and dephosphorylated during mitosis at different sites to orchestrate Golgi disassembly and reassembly during cell division, with phosphorylation of the T220/224 site being most critical in the process.

  4. Redox Switch for the Inhibited State of Yeast Glycogen Synthase Mimics Regulation by Phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Mahalingan, Krishna K.; Baskaran†, Sulochanadevi; DePaoli-Roach, Anna A.; Roach, Peter J.; Hurley, Thomas D. (Indiana-Med)

    2017-01-10

    Glycogen synthase (GS) is the rate limiting enzyme in the synthesis of glycogen. Eukaryotic GS is negatively regulated by covalent phosphorylation and allosterically activated by glucose-6-phosphate (G-6-P). To gain structural insights into the inhibited state of the enzyme, we solved the crystal structure of yGsy2-R589A/R592A to a resolution of 3.3 Å. The double mutant has an activity ratio similar to the phosphorylated enzyme and also retains the ability to be activated by G-6-P. When compared to the 2.88 Å structure of the wild-type G-6-P activated enzyme, the crystal structure of the low-activity mutant showed that the N-terminal domain of the inhibited state is tightly held against the dimer-related interface thereby hindering acceptor access to the catalytic cleft. On the basis of these two structural observations, we developed a reversible redox regulatory feature in yeast GS by substituting cysteine residues for two highly conserved arginine residues. When oxidized, the cysteine mutant enzyme exhibits activity levels similar to the phosphorylated enzyme but cannot be activated by G-6-P. Upon reduction, the cysteine mutant enzyme regains normal activity levels and regulatory response to G-6-P activation.

  5. Measuring brain glucose phosphorylation with labeled glucose

    International Nuclear Information System (INIS)

    Brondsted, H.E.; Gjedde, A.

    1988-01-01

    This study tested whether glucose labeled at the C-6 position generates metabolites that leave brain so rapidly that C-6-labeled glucose cannot be used to measure brain glucose phosphorylation (CMRGlc). In pentobarbital-anesthetized rats, the parietal cortex uptake of [ 14 C]glucose labeled in the C-6 position was followed for times ranging from 10 s to 60 min. We subtracted the observed radioactivity from the radioactivity expected with no loss of labeled metabolites from brain by extrapolation of glucose uptake in an initial period when loss was negligible. The observed radioactivity was a monoexponentially declining function of the total radioactivity expected in the absence of metabolite loss. The constant of decline was 0.0077.min-1 for parietal cortex. Metabolites were lost from the beginning of the experiment. However, with correction for the loss of labeled metabolites, it was possible to determine an average CMRGlc between 4 and 60 min of circulation of 64 +/- 4 (SE; n = 49) mumol.hg-1.min-1

  6. Phosphorylation site on yeast pyruvate dehydrogenase complex

    International Nuclear Information System (INIS)

    Uhlinger, D.J.

    1986-01-01

    The pyruvate dehydrogenase complex was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). Yeast cells were disrupted in a Manton-Gaulin laboratory homogenizer. The pyruvate dehydrogenase complex was purified by fractionation with polyethylene glycol, isoelectric precipitation, ultracentrifugation and chromatography on hydroxylapatite. Final purification of the yeast pyruvate dehydrogenase complex was achieved by cation-exchange high pressure liquid chromatography (HPLC). No endogenous pyruvate dehydrogenase kinase activity was detected during the purification. However, the yeast pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. Tryptic digestion of the 32 P-labeled complex yielded a single phosphopeptide which was purified to homogeniety. The tryptic digest was subjected to chromatography on a C-18 reverse phase HPLC column with a linear gradient of acetonitrile. Radioactive fractions were pooled, concentrated, and subjected to anion-exchange HPLC. The column was developed with a linear gradient of ammonium acetate. Final purification of the phosphopeptide was achieved by chromatography on a C-18 reverse phase HPLC column developed with a linear gradient of acetonitrile. The amino acid sequence of the homogeneous peptide was determined by manual modified Edman degradation

  7. Genome sequence of the organohalide-respiring Dehalogenimonas alkenigignens type strain (IP3-3(T)).

    Science.gov (United States)

    Key, Trent A; Richmond, Dray P; Bowman, Kimberly S; Cho, Yong-Joon; Chun, Jongsik; da Costa, Milton S; Rainey, Fred A; Moe, William M

    2016-01-01

    Dehalogenimonas alkenigignens IP3-3(T) is a strictly anaerobic, mesophilic, Gram negative staining bacterium that grows by organohalide respiration, coupling the oxidation of H2 to the reductive dehalogenation of polychlorinated alkanes. Growth has not been observed with any non-polyhalogenated alkane electron acceptors. Here we describe the features of strain IP3-3(T) together with genome sequence information and its annotation. The 1,849,792 bp high-quality-draft genome contains 1936 predicted protein coding genes, 47 tRNA genes, a single large subunit rRNA (23S-5S) locus, and a single, orphan, small unit rRNA (16S) locus. The genome contains 29 predicted reductive dehalogenase genes, a large majority of which lack cognate genes encoding membrane anchoring proteins.

  8. Merging metabolism and power: development of a novel photobioelectric device driven by photosynthesis and respiration.

    Directory of Open Access Journals (Sweden)

    Ryan J Powell

    Full Text Available Generation of renewable energy is one of the grand challenges facing our society. We present a new bio-electric technology driven by chemical gradients generated by photosynthesis and respiration. The system does not require pure cultures nor particular species as it works with the core metabolic principles that define phototrophs and heterotrophs. The biology is interfaced with electrochemistry with an alkaline aluminum oxide cell design. In field trials we show the system is robust and can work with an undefined natural microbial community. Power generated is light and photosynthesis dependent. It achieved a peak power output of 33 watts/m(2 electrode. The design is simple, low cost and works with the biological processes driving the system by removing waste products that can impede growth. This system is a new class of bio-electric device and may have practical implications for algal biofuel production and powering remote sensing devices.

  9. Csk-Induced Phosphorylation of Src at Tyrosine 530 is Essential for H2O2-Mediated Suppression of ERK1/2 in Human Umbilical Vein Endothelial Cells

    Science.gov (United States)

    Jeon, Bo Kyung; Kwon, Kihwan; Kang, Jihee Lee; Choi, Youn-Hee

    2015-01-01

    Mitogen-activated protein kinases (MAPKs) are key signal transducers involved in various cellular events such as growth, proliferation, and differentiation. Previous studies have reported that H2O2 leads to phosphorylation of extracellular signal-regulated kinase (ERK), one of the MAPKs in endothelial cells. The current study shows that H2O2 suppressed ERK1/2 activation and phosphorylation at specific concentrations and times in human umbilical vein endothelial cells but not in immortalized mouse aortic endothelial cells or human astrocytoma cell line CRT-MG. Phosphorylation of other MAPK family members (i.e., p38 and JNK) was not suppressed by H2O2. The decrease in ERK1/2 phosphorylation induced by H2O2 was inversely correlated with the level of phosphorylation of Src tyrosine 530. Using siRNA, it was found that H2O2-induced suppression of ERK1/2 was dependent on Csk. Physiological laminar flow abrogated, but oscillatory flow did not affect, the H2O2-induced suppression of ERK1/2 phosphorylation. In conclusion, H2O2-induced Csk translocation to the plasma membrane leads to phosphorylation of Src at the tyrosine 530 residue resulting in a reduction of ERK1/2 phosphorylation. Physiological laminar flow abrogates this effect of H2O2 by inducing phosphorylation of Src tyrosine 419. These findings broaden our understanding of signal transduction mechanisms in the endothelial cells against oxidative stress. PMID:26234813

  10. Respirable dust meter locates super polluters in traffic

    NARCIS (Netherlands)

    Schmidt-Ott's, A.; Kurniawan, A.; Schrauwers, A.

    2006-01-01

    The Netherlands is having trouble with the EU standards for respirable dust (PM 10). The Dutch Council of State recently blocked a number of residential development projects because local conditions failed to meet the PM 10 standard. Research by the Nano Structured Materials group at TU Delft shows

  11. Controls on winter ecosystem respiration in temperate and boreal ecosystems

    Science.gov (United States)

    T. Wang; P. Ciais; S.L. Piao; C. Ottle; P. Brender; F. Maignan; A. Arain; A. Cescatti; D. Gianelle; C. Gough; L Gu; P. Lafleur; T. Laurila; B. Marcolla; H. Margolis; L. Montagnani; E. Moors; N. Saigusa; T. Vesala; G. Wohlfahrt; C. Koven; A. Black; E. Dellwik; A. Don; D. Hollinger; A. Knohl; R. Monson; J. Munger; A. Suyker; A. Varlagin; S. Verma

    2011-01-01

    Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal...

  12. Plant species richness regulates soil respiration through changes in productivity.

    NARCIS (Netherlands)

    Tavares Correa Dias, A.; van Ruijven, J.; Berendse, F.

    2010-01-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

  13. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Czech Academy of Sciences Publication Activity Database

    Song, B.; Niu, S.; Luo, R.; Chen, J.; Yu, G.; Olejnik, Janusz; Wohlfahrt, G.; Kiely, G.; Noormels, A.; Montagnani, L.; Cescatti, A.; Magliulo, V.; Law, B. E.; Lund, M.; Varlagin, A.; Raschi, A.; Peichl, M.; Nilsson, M.; Merbold, L.

    2014-01-01

    Roč. 7, č. 5 (2014), s. 419-428 ISSN 1752-9921 Institutional support: RVO:67179843 Keywords : activation energy * ecosystem respiration * index of water availability * gross primary productivity Subject RIV: EH - Ecology, Behaviour Impact factor: 2.646, year: 2014

  14. 75 FR 29699 - Total Inward Leakage Requirements for Respirators

    Science.gov (United States)

    2010-05-27

    ... or other half-mask respirator inward leakage measurement, and offer any additional comments on the..., facsimile (412) 386-4089, e-mail [email protected] . SUPPLEMENTARY INFORMATION: I. Background The Department of... order to conduct tests and prepare responses. On April 20, 2010, NIOSH responded by reopening the docket...

  15. Soil respiration in Mexico: Advances and future directions

    Directory of Open Access Journals (Sweden)

    Alejandro Cueva

    2016-07-01

    Full Text Available Soil respiration (RS is a CO2 efflux from the soil to the atmosphere defined as the sum of autotrophic (respiration by roots and mycorrhizae, and heterotrophic (respiration of microorganisms that decompose fractions of organic matter and of soil fauna respiration. Globally, RS is considered to be the second largest flux of C to the atmosphere. From published literature it is clear that its main controls are soil temperature, soil moisture, photosynthesis, organic matter inputs and soil biota composition. Despite its relevance in C cycle science, there have been only twenty eight studies in Mexico in the last decade where direct measurement of gas exchange was conducted in the field. These studies were held mostly in agricultural and forest ecosystems, in Central and Southern Mexico where mild subtropical conditions prevail. However, arid, semi-arid, tropical and wetland ecosystems may have an important role in Mexico’s CO2 emissions because of their extent and extensive land use changes. From the twenty eight studies, only two provided continuous measurements of RS with high temporal resolution, highlighting the need for long-term studies to evaluate the complex biophysical controls of this flux and associated processes over different ecological succession stages. We conclude that Mexico represents an important opportunity to understand its complex dynamics, in national and global context, as ecosystems in the country cover a wide range of climatic conditions. This is particularly important because deforestation and degradation of Mexican ecosystems is rapidly increasing along with expected changes in climate.

  16. Understanding Cellular Respiration in Terms of Matter & Energy within Ecosystems

    Science.gov (United States)

    White, Joshua S.; Maskiewicz, April C.

    2014-01-01

    Using a design-based research approach, we developed a data-rich problem (DRP) set to improve student understanding of cellular respiration at the ecosystem level. The problem tasks engage students in data analysis to develop biological explanations. Several of the tasks and their implementation are described. Quantitative results suggest that…

  17. Estimating autotrophic respiration in streams using daily metabolism data

    Science.gov (United States)

    Knowing the fraction of gross primary production (GPP) that is immediately respired by autotrophs and their closely associated heterotrophs (ARf) is necessary to understand the trophic base and carbon spiraling in streams. We show a means to estimate ARf from daily metabolism da...

  18. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  19. Temperature response of soil respiration largely unaltered with experimental warming

    NARCIS (Netherlands)

    Carey, J.C.; Tang, J.; Templer, P.H.; Kroeger, K.D.; Crowther, T.W.; Burton, A.J.; Dukes, J.S.; Emmett, B.; Frey, S.D.; Heskel, M.A.; Jiang, L.; Machmuller, M.B.; Mohan, J.; Panetta, A.M.; Reich, P.B.; Reinsch, S.; Wang, X.; Allison, S.D.; Bamminger, C.; Bridgham, S.; Collins, S.L.; de Dato, G.; Eddy, W.C.; Enquist, B.J.; Estiarte, M.; Harte, J.; Henderson, A.; Johnson, B.R.; Larsen, K.S.; Luo, Y.; Marhan, S.; Melillo, J.M.; Peñuelas, J.; Pfeifer-Meister, L.; Poll, C.; Rastetter, E.; Reinmann, A.B.; Reynolds, L.L.; Schmidt, I.K.; Shaver, G.R.; Strong, A.L.; Suseela, V.; Tietema, A.

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific

  20. Plant species richness regulates soil respiration through changes in productivity

    NARCIS (Netherlands)

    Dias, A.A.; Ruijven, van J.; Berendse, F.

    2010-01-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

  1. Tillage and manure effect on soil microbial biomass and respiration ...

    African Journals Online (AJOL)

    The objective of this study was to determine the influence of both tillage and liquid pig manure application on soil microbial biomass, enzyme activities and microbial respiration in a meadow soil. The results obtained did not show any significant effect of tillage and manure on microbial biomass carbon (C) and nitrogen (N) ...

  2. Connecting Photosynthesis and Cellular Respiration: Preservice Teachers' Conceptions

    Science.gov (United States)

    Brown, Mary H.; Schwartz, Renee S.

    2009-01-01

    The biological processes of photosynthesis and plant cellular respiration include multiple biochemical steps, occur simultaneously within plant cells, and share common molecular components. Yet, learners often compartmentalize functions and specialization of cell organelles relevant to these two processes, without considering the interconnections…

  3. Pulmonary inflammation and crystalline silica in respirable coal ...

    Indian Academy of Sciences (India)

    Unknown

    This study demonstrates dose-response relationships between respirable crystalline silica in coal mine dust and pulmonary inflammation, antioxidant production, and radiographic small opacities. [Kuempel E D, Attfield M D, Vallyathan V, Lapp N L, Hale J M, Smith R J and Castranova V 2003 Pulmonary inflammation and ...

  4. Quantitative change of EEG and respiration signals during mindfulness meditation

    Science.gov (United States)

    2014-01-01

    Background This study investigates measures of mindfulness meditation (MM) as a mental practice, in which a resting but alert state of mind is maintained. A population of older people with high stress level participated in this study, while electroencephalographic (EEG) and respiration signals were recorded during a MM intervention. The physiological signals during meditation and control conditions were analyzed with signal processing. Methods EEG and respiration data were collected and analyzed on 34 novice meditators after a 6-week meditation intervention. Collected data were analyzed with spectral analysis, phase analysis and classification to evaluate an objective marker for meditation. Results Different frequency bands showed differences in meditation and control conditions. Furthermore, we established a classifier using EEG and respiration signals with a higher accuracy (85%) at discriminating between meditation and control conditions than a classifier using the EEG signal only (78%). Conclusion Support vector machine (SVM) classifier with EEG and respiration feature vector is a viable objective marker for meditation ability. This classifier should be able to quantify different levels of meditation depth and meditation experience in future studies. PMID:24939519

  5. ECG-derived respiration methods: adapted ICA and PCA.

    Science.gov (United States)

    Tiinanen, Suvi; Noponen, Kai; Tulppo, Mikko; Kiviniemi, Antti; Seppänen, Tapio

    2015-05-01

    Respiration is an important signal in early diagnostics, prediction, and treatment of several diseases. Moreover, a growing trend toward ambulatory measurements outside laboratory environments encourages developing indirect measurement methods such as ECG derived respiration (EDR). Recently, decomposition techniques like principal component analysis (PCA), and its nonlinear version, kernel PCA (KPCA), have been used to derive a surrogate respiration signal from single-channel ECG. In this paper, we propose an adapted independent component analysis (AICA) algorithm to obtain EDR signal, and extend the normal linear PCA technique based on the best principal component (PC) selection (APCA, adapted PCA) to improve its performance further. We also demonstrate that the usage of smoothing spline resampling and bandpass-filtering improve the performance of all EDR methods. Compared with other recent EDR methods using correlation coefficient and magnitude squared coherence, the proposed AICA and APCA yield a statistically significant improvement with correlations 0.84, 0.82, 0.76 and coherences 0.90, 0.91, 0.85 between reference respiration and AICA, APCA and KPCA, respectively. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. Ecophysiology and environmental distribution of organohalide-respiring bacteria

    NARCIS (Netherlands)

    Lu, Y.

    2016-01-01

    Organohalide-respiring bacteria (OHRB) are able to breathe natural and anthropogenically produced organohalides persistent in a broad range of oxygen-depleted environments. Therefore, these microorganisms are of high interest for organohalide-contaminated site bioremediation and natural halogen

  7. 30 CFR 71.100 - Respirable dust standard.

    Science.gov (United States)

    2010-07-01

    ... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... shall be measured with an approved sampling device and expressed in terms of an equivalent concentration determined in accordance with § 71.206 (Approved sampling devices; equivalent concentrations). ...

  8. Diatoms respire nitrate to survive dark and anoxic conditions

    DEFF Research Database (Denmark)

    Kamp, Anja; de Beer, Dirk; Nitsch, Jana L.

    2011-01-01

    +, indicating dissimilatory nitrate reduction to ammo- nium (DNRA). DNRA is an anaerobic respiration process that is known mainly from prokaryotic organisms, and here shown as dis- similatory nitrate reduction pathway used by a eukaryotic photo- troph. Similar to large sulfur bacteria and benthic foraminifera...

  9. Hydrological controls on heterotrophic soil respiration across an agricultural landscape

    Science.gov (United States)

    Water availability is an important determinant of variation in soil respiration, but a consistent relationship between soil water and the relative flux rate of carbon dioxide across different soil types remains elusive. Using large undisturbed soil columns (N = 12), we evaluated soil water controls...

  10. Gap filling strategies and error in estimating annual soil respiration

    Science.gov (United States)

    Soil respiration (Rsoil) is one of the largest CO2 fluxes in the global carbon (C) cycle. Estimation of annual Rsoil requires extrapolation of survey measurements or gap-filling of automated records to produce a complete time series. While many gap-filling methodologies have been employed, there is ...

  11. Meetings: Issues and recent advances in soil respiration

    Science.gov (United States)

    K.A. Hibbard; B.E. Law

    2004-01-01

    The terrestrial carbon cycle is intriniscally tied to climate, hydrology, nutrient cycles, and the production of biomass through photosynthesis. Over two-thirds of terrestrial carbon is stored below ground in soils, and a significant amount of atmospheric CO2 is processed by soils every year. Thus, soil respiration is a key process that underlies...

  12. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    Directory of Open Access Journals (Sweden)

    Shohei Sakuda

    2014-03-01

    Full Text Available Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control.

  13. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    Science.gov (United States)

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-01-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  14. Impact of some selected insecticides application on soil microbial respiration.

    Science.gov (United States)

    Latif, M A; Razzaque, M A; Rahman, M M

    2008-08-15

    The aim of present study was to investigate the impact of selected insecticides used for controlling brinjal shoot and fruit borer on soil microorganisms and to find out the insecticides or nontoxic to soil microorganism the impact of nine selected insecticides on soil microbial respiration was studied in the laboratory. After injection of different insecticides solutions, the soil was incubated in the laboratory at room temperature for 32 days. The amount of CO2 evolved due to soil microbial respiration was determined at 2, 4, 8, 16, 24 and 32 days of incubation. Flubendiamide, nimbicidine, lambda-cyhalothrin, abamectin and thiodicarb had stimulatory effect on microbial respiration during the initial period of incubation. Chlorpyriphos, cartap and carbosulfan had inhibitory effect on microbial respiration and cypermethrin had no remarkable effect during the early stage of incubation. The negative effect of chlorpyriphos, cartap and carbosulfan was temporary, which was disappeared after 4 days of insecticides application. No effect of the selected insecticides on soil microorganisms was observed after 24 or 32 days of incubation.

  15. Inhibiting prenylation augments chemotherapy efficacy in renal cell carcinoma through dual inhibition on mitochondrial respiration and glycolysis.

    Science.gov (United States)

    Huang, Jiangrong; Yang, Xiaoyu; Peng, Xiaochun; Huang, Wei

    2017-11-18

    Preny