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Sample records for aluminum-inducible malate release

  1. Long non-coding RNA MALAT1 promotes tumour growth and metastasis in colorectal cancer through binding to SFPQ and releasing oncogene PTBP2 from SFPQ/PTBP2 complex

    PubMed Central

    Ji, Q; Zhang, L; Liu, X; Zhou, L; Wang, W; Han, Z; Sui, H; Tang, Y; Wang, Y; Liu, N; Ren, J; Hou, F; Li, Q

    2014-01-01

    Background: Metastasis associated with lung adenocarcinoma transcript-1 (MALAT1) is a functional long non-coding RNA (lncRNA), which is highly expressed in several tumours, including colorectal cancer (CRC). Its biological function and mechanism in the prognosis of human CRC is still largely under investigation. Methods: This study aimed to investigate the new effect mechanism of MALAT1 on the proliferation and migration of CRC cells in vitro and in vivo, and detect the expression of MALAT1, SFPQ (also known as PSF (PTB-associated splicing factor)), and PTBP2 (also known as PTB (polypyrimidine-tract-binding protein)) in CRC tumour tissues, followed by correlated analysis with clinicopathological parameters. Results: We found that overexpression of MALAT1 could promote cell proliferation and migration in vitro, and promote tumour growth and metastasis in nude mice. The underlying mechanism was associated with tumour suppressor gene SFPQ and proto-oncogene PTBP2. In CRC, MALAT1 could bind to SFPQ, thus releasing PTBP2 from the SFPQ/PTBP2 complex. In turn, the increased SFPQ-detached PTBP2 promoted cell proliferation and migration. SFPQ critically mediated the regulatory effects of MALAT1. Moreover, in CRC tissues, MALAT1 and PTBP2 were overexpressed, both of which were associated closely with the invasion and metastasis of CRC. However, the SFPQ showed unchanged expression either in CRC tissues or adjacent normal tissues. Conclusions: Our findings implied that MALAT1 might be a potential predictor for tumour metastasis and prognosis. Furthermore, the interaction between MALAT1 and SFPQ could be a novel therapeutic target for CRC. PMID:25025966

  2. Aluminum-induced granulomas in a tattoo

    SciTech Connect

    McFadden, N.; Lyberg, T.; Hensten-Pettersen, A.

    1989-05-01

    A patient who developed localized, granulomatous reactions in a tattoo is described. With the use of scanning electron microscopy and energy dispersive x-ray microanalysis, both aluminum and titanium particles were found in the involved skin sections. Intradermal provocation testing with separate suspensions of aluminum and titanium induced a positive response only in the case of aluminum. Examination by scanning electron microscopy and energy dispersive x-ray microanalysis of the provoked response established aluminum as the only nonorganic element present in the test site tissue. This is the first report of confirmed aluminum-induced, delayed-hypersensitivity granulomas in a tattoo.

  3. Pyruvate and Malate Transport and Oxidation in Corn Mitochondria 1

    PubMed Central

    Day, David A.; Hanson, John B.

    1977-01-01

    Pyruvate oxidation and swelling in pyruvate solutions by corn (Zea mays) mitochondria were inhibited by α-cyano-4-hydroxy-cinnamic acid, an inhibitor of pyruvate transport in animal mitochondria; however, there was no inhibition of pyruvate dehydrogenase activity, and malate and NADH oxidation were not affected. These results suggest the presence of a pyruvate−-OH− exchange transporter which supplies the mitochondrion with oxidizable substrate. Lactate appears to be transported also, but not dicarboxylate anions or inorganic phosphate. The rate of pyruvate transport was much slower than that of malate, however, and valinomycin was required to elicit appreciable swelling in potassium pyruvate. Malate oxidation contributed significantly to respiration supported by pyruvate plus malate, and malate did not act solely as a “sparker” for pyruvate oxidation. NAD+-malic enzyme activity was found in sonicated preparations, and comparison of O2 consumption with CO2 released from 1-14C-pyruvate indicated that transported malate was being converted to pyruvate, particularly as the malate to pyruvate ratio increased. The results suggest that pyruvate transport becomes limiting under conditions of high energy demand, but that rapid malate transport makes up the difference, supplying pyruvate via malic enzyme and replenishing losses of tricarboxylic acid cycle intermediates. PMID:16659908

  4. Rivastigmine reverses aluminum-induced behavioral changes in rats.

    PubMed

    Abdel-Aal, Raafat A; Assi, Abdel-Azim A; Kostandy, Botros B

    2011-06-01

    Aluminum, a known neurotoxin, has long been implicated in the pathogenesis of Alzheimer's disease. Its exposure is associated with impairment in the cholinergic system in the brain. In this study we investigated the behavioral effects of aluminum in rats and the possible effect of rivastigmine, a cholinesterase inhibitor, on the aluminum-induced behavioral changes. Rats were exposed to aluminum chloride (100 mg/kg/day i.p.) for 60 days before the start of behavioral tests. Rivastigmine was given in doses of 0.5, 1, 1.5 and 2.5 mg/kg i.p. 60 min before the behavioral tests. Five tests were investigated; open field test, Morris water maze, radial arm maze, passive avoidance test and rota-rod test. Results showed that aluminum exposure was associated with significant reductions in spontaneous locomotor and exploratory activities in open field test and significant impairments in learning and memory in Morris water maze, radial arm maze and passive avoidance tests. The behavioral impairments caused by aluminum were significantly improved by rivastigmine. Neither aluminum alone nor co-treatment with rivastigmine caused any significant alteration of the animals' performance in rota-rod test. The improvements in activity, learning and memory caused by rivastigmine were found to be dose-dependent, and the maximal improvement was encountered with its large dose (2.5 mg/kg). From these results we can conclude that rivastigmine can reverse behavioral deficits caused by aluminum intoxication.

  5. Malate synthase a membrane protein

    SciTech Connect

    Chapman, K.D.; Turley, R.B.; Hermerath, C.A.; Carrapico, F.; Trelease, R.N.

    1987-04-01

    Malate synthase (MS) is generally regarded as a peripheral membrane protein, and believed by some to be ontogenetically associated with ER. However, immuno- and cyto-chemical in situ localizations show MS throughout the matrix of cotton (and cucumber) glyoxysomes, not specifically near their boundary membranes, nor in ER. Only a maximum of 50% MS can be solubilized from cotton glyoxysomes with 1% Triton X-100, 2mM Zwittergen 14, or 10mM DOC +/- salts. Cotton MS does not incorporate /sup 3/H-glucosamine in vivo, nor does it react with Con A on columns or blots. Cotton MS banded with ER in sucrose gradients (20-40%) in Tricine after 3h, but not after 22h in Tricine or Hepes, or after 3h in Hepes or K-phosphate. Collectively the authors data are inconsistent with physiologically meaningful MS-membrane associations in ER or glyoxysomes. It appears that experimentally-induced aggregates of MS migrate in ER gradients and occur in isolated glyoxysomes. These data indicate that ER is not involved in synthesis or modification of cottonseed MS prior to its import into the glyoxysomal matrix.

  6. The metabolism of malate by cultured rat brain astrocytes

    SciTech Connect

    McKenna, M.C.; Tildon, J.T.; Couto, R.; Stevenson, J.H.; Caprio, F.J. )

    1990-12-01

    Since malate is known to play an important role in a variety of functions in the brain including energy metabolism, the transfer of reducing equivalents and possibly metabolic trafficking between different cell types; a series of biochemical determinations were initiated to evaluate the rate of 14CO2 production from L-(U-14C)malate in rat brain astrocytes. The 14CO2 production from labeled malate was almost totally suppressed by the metabolic inhibitors rotenone and antimycin A suggesting that most of malate metabolism was coupled to the electron transport system. A double reciprocal plot of the 14CO2 production from the metabolism of labeled malate revealed biphasic kinetics with two apparent Km and Vmax values suggesting the presence of more than one mechanism of malate metabolism in these cells. Subsequent experiments were carried out using 0.01 mM and 0.5 mM malate to determine whether the addition of effectors would differentially alter the metabolism of high and low concentrations of malate. Effectors studied included compounds which could be endogenous regulators of malate metabolism and metabolic inhibitors which would provide information regarding the mechanisms regulating malate metabolism. Both lactate and aspartate decreased 14CO2 production from malate equally. However, a number of effectors were identified which selectively altered the metabolism of 0.01 mM malate including aminooxyacetate, furosemide, N-acetylaspartate, oxaloacetate, pyruvate and glucose, but had little or no effect on the metabolism of 0.5 mM malate. In addition, alpha-ketoglutarate and succinate decreased 14CO2 production from 0.01 mM malate much more than from 0.5 mM malate. In contrast, a number of effectors altered the metabolism of 0.5 mM malate more than 0.01 mM. These included methionine sulfoximine, glutamate, malonate, alpha-cyano-4-hydroxycinnamate and ouabain.

  7. The ABC transporter AtABCB14 is a malate importer and modulates stomatal response to CO2.

    PubMed

    Lee, Miyoung; Choi, Yongwook; Burla, Bo; Kim, Yu-Young; Jeon, Byeongwook; Maeshima, Masayoshi; Yoo, Joo-Yeon; Martinoia, Enrico; Lee, Youngsook

    2008-10-01

    Carbon dioxide uptake and water vapour release in plants occur through stomata, which are formed by guard cells. These cells respond to light intensity, CO2 and water availability, and plant hormones. The predicted increase in the atmospheric concentration of CO2 is expected to have a profound effect on our ecosystem. However, many aspects of CO2-dependent stomatal movements are still not understood. Here we show that the ABC transporter AtABCB14 modulates stomatal closure on transition to elevated CO2. Stomatal closure induced by high CO2 levels was accelerated in plants lacking AtABCB14. Apoplastic malate has been suggested to be one of the factors mediating the stomatal response to CO2 (Refs 4,5) and indeed, exogenously applied malate induced a similar AtABCB14-dependent response as high CO2 levels. In isolated epidermal strips that contained only guard cells, malate-dependent stomatal closure was faster in plants lacking the AtABCB14 and slower in AtABCB14-overexpressing plants, than in wild-type plants, indicating that AtABCB14 catalyses the transport of malate from the apoplast into guard cells. Indeed, when AtABCB14 was heterologously expressed in Escherichia coli and HeLa cells, increases in malate transport activity were observed. We therefore suggest that AtABCB14 modulates stomatal movement by transporting malate from the apoplast into guard cells, thereby increasing their osmotic pressure.

  8. EFFECTS OF ALUMINUM-INDUCED AGGREGATION ON THE FLUORESCENCE OF HUMIC SUBSTANCES. (R822251)

    EPA Science Inventory

    Aluminum-induced aggregates of terrestrial and aquatic humic acid standards from the International Humic Substances Society are shown to be fluorescent by means of a multiwavelength fluorescence anisotropy experiment in which the data was treated with a model for nonspherical ...

  9. Cytotoxic thio-malate is transported by both an aluminum-responsive malate efflux pathway in wheat and the MAE1 malate permease in Schizosaccharomyces pombe.

    PubMed

    Osawa, Hiroki; Matsumoto, Hideaki

    2006-07-01

    Aluminum (Al) tolerance in wheat (Triticum aestivum L.) is mainly achieved by malate efflux, which is regulated by the expression of the recently identified gene, presumably encoding an Al-activated malate efflux transporter (ALMT1). However, the transport mechanism is not fully understood, partly as a result of the rapid turnover of its substrate. We developed a tool to study malate transport in wheat by screening biological compounds using the well-characterized Schizosaccharomyces pombe malate transporter (SpMAE1). Expression of SpMAE1 in both S. pombe and Saccharomyces cerevisiae, which has no SpMAE1 homologue, caused hypersensitivity to thio-malic acid. This hypersensitivity was prominent at pH 3.5, but not pH 4.5, and was accompanied by an increase in thiol content, indicating that SpMAE1 mediates the uptake of thio-malic acid at a specific low pH. In wheat, root apices were able to accumulate thio-malic acid without growth reduction at pH values above 4.2. Pretreatment of root apices with thio-malic acid followed by Al treatment induced thio-malate efflux. Al-induced thio-malate efflux was much higher in Al-resistant cultivars/genotypes than in Al-sensitive ones, and was accompanied by a decrease in thiol-content. Thio-malate efflux in the Al-resistant cultivar was slightly activated by lanthanum or ytterbium ion. Thio-malic acid did not alleviate the Al-induced inhibition of root elongation in wheat. Taken together, our results suggest that thio-malate acts as an analogue for malate in malate transport systems in wheat and yeast, and that it may be a useful tool for the analysis of malate transport involved in Al-tolerance and of other organic ion transport processes.

  10. A chimeric protein of aluminum-activated malate transporter generated from wheat and Arabidopsis shows enhanced response to trivalent cations.

    PubMed

    Sasaki, Takayuki; Tsuchiya, Yoshiyuki; Ariyoshi, Michiyo; Ryan, Peter R; Yamamoto, Yoko

    2016-07-01

    TaALMT1 from wheat (Triticum aestivum) and AtALMT1 from Arabidopsis thaliana encode aluminum (Al)-activated malate transporters, which confer acid-soil tolerance by releasing malate from roots. Chimeric proteins from TaALMT1 and AtALMT1 (Ta::At, At::Ta) were previously analyzed in Xenopus laevis oocytes. Those studies showed that Al could activate malate efflux from the Ta::At chimera but not from At::Ta. Here, functions of TaALMT1, AtALMT1 and the chimeric protein Ta::At were compared in cultured tobacco BY-2 cells. We focused on the sensitivity and specificity of their activation by trivalent cations. The activation of malate efflux by Al was at least two-fold greater in the chimera than the native proteins. All proteins were also activated by lanthanides (erbium, ytterbium, gadolinium, and lanthanum), but the chimera again released more malate than TaALMT1 or AtALMT1. In Xenopus oocytes, Al, ytterbium, and erbium activated inward currents from the native TaALMT1 and the chimeric protein, but gadolinium only activated currents from the chimera. Lanthanum inhibited currents from both proteins. These results demonstrated that function of the chimera protein was altered compared to the native proteins and was more responsive to a range of trivalent cations when expressed in plant cells. PMID:27039280

  11. Aluminum-induced pneumoconiosis confirmed by analytical scanning electron microscopy: A case report and review of the literature.

    PubMed

    Carney, John; McAdams, Page; McCluskey, James; Roggli, Victor L

    2016-01-01

    Aluminum-induced lung injury is an uncommon, yet recognized pneumoconiosis capable of causing severe interstitial fibrosis. Important attention to the clinical history including occupational exposure is an essential component to making the correct diagnosis, despite which careful examination of the lung specimen is necessary to exclude other more common disease entities. We present a case of aluminum-induced pneumoconiosis in the setting of a bilateral lung transplant patient. Additionally, we review the literature on aluminum-induced pneumoconiosis and demonstrate the use of ancillary techniques including backscattered electron imaging and energy-dispersive spectrometry to aid in diagnosis.

  12. Malate and Fumarate Extend Lifespan in Caenorhabditis elegans

    PubMed Central

    Edwards, Clare B.; Copes, Neil; Brito, Andres G.; Canfield, John; Bradshaw, Patrick C.

    2013-01-01

    Malate, the tricarboxylic acid (TCA) cycle metabolite, increased lifespan and thermotolerance in the nematode C. elegans. Malate can be synthesized from fumarate by the enzyme fumarase and further oxidized to oxaloacetate by malate dehydrogenase with the accompanying reduction of NAD. Addition of fumarate also extended lifespan, but succinate addition did not, although all three intermediates activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced oxidative stress. The glyoxylate shunt, an anabolic pathway linked to lifespan extension in C. elegans, reversibly converts isocitrate and acetyl-CoA to succinate, malate, and CoA. The increased longevity provided by malate addition did not occur in fumarase (fum-1), glyoxylate shunt (gei-7), succinate dehydrogenase flavoprotein (sdha-2), or soluble fumarate reductase F48E8.3 RNAi knockdown worms. Therefore, to increase lifespan, malate must be first converted to fumarate, then fumarate must be reduced to succinate by soluble fumarate reductase and the mitochondrial electron transport chain complex II. Reduction of fumarate to succinate is coupled with the oxidation of FADH2 to FAD. Lifespan extension induced by malate depended upon the longevity regulators DAF-16 and SIR-2.1. Malate supplementation did not extend the lifespan of long-lived eat-2 mutant worms, a model of dietary restriction. Malate and fumarate addition increased oxygen consumption, but decreased ATP levels and mitochondrial membrane potential suggesting a mild uncoupling of oxidative phosphorylation. Malate also increased NADPH, NAD, and the NAD/NADH ratio. Fumarate reduction, glyoxylate shunt activity, and mild mitochondrial uncoupling likely contribute to the lifespan extension induced by malate and fumarate by increasing the amount of oxidized NAD and FAD cofactors. PMID:23472183

  13. Arsenic mobilization by citrate and malate from a red mud-treated contaminated soil.

    PubMed

    Castaldi, Paola; Silvetti, Margherita; Mele, Elena; Garau, Giovanni; Deiana, Salvatore

    2013-01-01

    The mobility and bioavailability of As in the soil-plant system can be affected by a number of organic acids that originate from the activity of plants and microorganisms. In this study we evaluated the ability of citrate and malate anions to mobilize As in a polluted subacidic soil (UP soil) treated with red mud (RM soil). Both anions promoted the mobilization of As from UP and RM soils, with citrate being more effective than malate. The RM treatment induced a greater mobility of As. The amounts of As released in RM and UP soils treated with 3.0 mmol L citric acid solution were 2.78 and 1.83 μmol g respectively, whereas an amount equal to 1.73 and 1.06 μmol g was found after the treatment with a 3.0 mmol L malic acid solution. The release of As in both soils increased with increasing concentration of organic acids, and the co-release of Al and Fe in solution also increased. The sequential extraction showed that Fe/Al (oxi)hydroxides in RM were the main phases involved in As binding in RM soil. Two possible mechanisms could be responsible for As solubilization: (i) competition of the organic anions for As adsorption sites and (ii) partial dissolution of the adsorbents (e.g., dissolution of iron and aluminum oxi-hydroxides) induced by citrate or malate and formation of complexes between dissolved Fe and Al and organic anions. This is the first report on the effect of malate and citrate on the As mobility in a polluted soil treated with RM.

  14. Counteractive Effects of ABA and GA3 on Extracellular and Intracellular pH and Malate in Barley Aleurone.

    PubMed

    Heimovaara-Dijkstra, S.; Heistek, J. C.; Wang, M.

    1994-09-01

    Barley (Hordeum vulgare L.) aleurone layers are known to constitutively acidify their surroundings, primarily by L-malic acid release (J. Mikola, M. Virtanen [1980] Plant Physiol 66: S-142). Here we demonstrate the antagonistic effects of the plant hormones gibberellic acid (GA3) and abscisic acid (ABA) on the regulation of extracellular pH (pHe) of barley aleurone layers. We observed a strong correlation between ABA-induced enhancement of extracellular acidification and an ABA-induced increase in L-malic acid release. In addition, ABA caused an increase in intracellular L-malate level. GA3 caused a slight decrease in intracellular L-malate level and was able to inhibit the ABA-induced increase in L-malate intracellular concentration and release. In addition, this ABA-induced L-malate release could be completely inhibited by GA3. The ABA-induced release of L-malic acid could not account for the total ABA-induced pHe decrease, suggesting the existence of an additional mechanism involved in the regulation of pHe. It has been reported that ABA induces an intracellular pH (pHi) increase, possibly due to the activation of plasma membrane proton pumps (R. Van der Veen, S. Heimovaara-Dijkstra, M. Wang [1992] Plant Physiol 100: 699-705). A pHi increase, such as that caused by ABA, might be correlated with the intracellular L-malate increase as suggested by the pH stat model of D.D. Davies ([1986] Physiol Plant 67: 702-706). We studied if the effects of GA3 on L-malate concentration were correlated with changes in pHi and found that GA3 caused a pHi decrease and that GA3 and ABA could interfere in the regulation of pHi. In addition, we were able to mimic the effect of both hormones on L-malate release by bringing about artifical pHi changes with the weak acid 5,5-dimethyl-2,4-oxazolidinedione and the weak base methylamine. The physiological meaning of the effects of GA3 and ABA on the regulation of both pHe and pHi during grain germination are discussed.

  15. Counteractive Effects of ABA and GA3 on Extracellular and Intracellular pH and Malate in Barley Aleurone.

    PubMed Central

    Heimovaara-Dijkstra, S.; Heistek, J. C.; Wang, M.

    1994-01-01

    Barley (Hordeum vulgare L.) aleurone layers are known to constitutively acidify their surroundings, primarily by L-malic acid release (J. Mikola, M. Virtanen [1980] Plant Physiol 66: S-142). Here we demonstrate the antagonistic effects of the plant hormones gibberellic acid (GA3) and abscisic acid (ABA) on the regulation of extracellular pH (pHe) of barley aleurone layers. We observed a strong correlation between ABA-induced enhancement of extracellular acidification and an ABA-induced increase in L-malic acid release. In addition, ABA caused an increase in intracellular L-malate level. GA3 caused a slight decrease in intracellular L-malate level and was able to inhibit the ABA-induced increase in L-malate intracellular concentration and release. In addition, this ABA-induced L-malate release could be completely inhibited by GA3. The ABA-induced release of L-malic acid could not account for the total ABA-induced pHe decrease, suggesting the existence of an additional mechanism involved in the regulation of pHe. It has been reported that ABA induces an intracellular pH (pHi) increase, possibly due to the activation of plasma membrane proton pumps (R. Van der Veen, S. Heimovaara-Dijkstra, M. Wang [1992] Plant Physiol 100: 699-705). A pHi increase, such as that caused by ABA, might be correlated with the intracellular L-malate increase as suggested by the pH stat model of D.D. Davies ([1986] Physiol Plant 67: 702-706). We studied if the effects of GA3 on L-malate concentration were correlated with changes in pHi and found that GA3 caused a pHi decrease and that GA3 and ABA could interfere in the regulation of pHi. In addition, we were able to mimic the effect of both hormones on L-malate release by bringing about artifical pHi changes with the weak acid 5,5-dimethyl-2,4-oxazolidinedione and the weak base methylamine. The physiological meaning of the effects of GA3 and ABA on the regulation of both pHe and pHi during grain germination are discussed. PMID:12232334

  16. Materials and methods for efficient succinate and malate production

    DOEpatents

    Jantama, Kaemwich; Haupt, Mark John; Zhang, Xueli; Moore, Jonathan C; Shanmugam, Keelnatham T; Ingram, Lonnie O'Neal

    2014-04-08

    Genetically engineered microorganisms have been constructed to produce succinate and malate in mineral salt media in pH-controlled batch fermentations without the addition of plasmids or foreign genes. The subject invention also provides methods of producing succinate and malate comprising the culture of genetically modified microorganisms.

  17. Effects of citrulline malate on bacterial lipopolysaccharide induced endotoxemia in rats.

    PubMed

    Verleye, M; Heulard, I; Stephens, J R; Levy, R H; Gillardin, J M

    1995-06-01

    The administration of endotoxins to rats as lipopolysaccharides (LPS) induces a state of exhaustion, in which the main symptoms are febrile hyperthermia, reduced food intake, decreased body weight, and reduced muscle performance in treadmill tests. Underlying the physiological and behavioral disturbances due to the LPS is the activation of macrophages that release cytokines (interleukin-1, tumor necrosis factor a) and NO. The cellular responses are intended to maintain homeostasis. Provision of citrulline as citrulline malate (CAS 54940-97-5, Stimol), an antifatigue substance, improved muscle performance, but had no effect on the body temperature or on the body weight of these animals weakened by LPS. The presence of citrulline in the NO synthesis pathway, or its participation in the speeded up elimination of ammonia and lactates, the main products of muscle metabolism, might explain the effects of citrulline malate in rats treated with LPS. PMID:7646577

  18. Pattern of aluminum-induced secretion of organic acids differs between rye and wheat.

    PubMed

    Li, X F; Ma, J F; Matsumoto, H

    2000-08-01

    Al-Induced secretion of organic acids from the roots has been considered as a mechanism of Al tolerance, but the processes leading to the secretion of organic acids are still unknown. In this study, the secretion pattern and alteration in the metabolism of organic acids under Al stress were examined in rye (Secale cereale L. cv King) and wheat (Triticum aestivum L. cv Atlas 66). Al induced rapid secretion of malate in the wheat, but a lag (6 and 10 h for malic and citric acids, respectively) between the exposure to Al and the secretion of organic acids was observed in the rye. The activities of isocitrate dehydrogenase, phosphoenolpyruvate carboxylase, and malate dehydrogenase were not affected by Al in either plant. The activity of citrate synthase was increased by the exposure to Al in the rye, but not in the wheat. The secretion of malate was not suppressed at low temperature in the wheat, but that of citrate was stopped in the rye. The Al-induced secretion of citrate from roots of the rye was inhibited by the inhibitors of a citrate carrier, which transports citrate from the mitochondria to the cytoplasm. All of these results suggest that alteration in the metabolism of organic acids is involved in the Al-induced secretion of organic acids in rye, but only activation of an anion channel seems to be responsible for the rapid secretion of malate in the wheat.

  19. Low pH, Aluminum, and Phosphorus Coordinately Regulate Malate Exudation through GmALMT1 to Improve Soybean Adaptation to Acid Soils1[W][OA

    PubMed Central

    Liang, Cuiyue; Piñeros, Miguel A.; Tian, Jiang; Yao, Zhufang; Sun, Lili; Liu, Jiping; Shaff, Jon; Coluccio, Alison; Kochian, Leon V.; Liao, Hong

    2013-01-01

    Low pH, aluminum (Al) toxicity, and low phosphorus (P) often coexist and are heterogeneously distributed in acid soils. To date, the underlying mechanisms of crop adaptation to these multiple factors on acid soils remain poorly understood. In this study, we found that P addition to acid soils could stimulate Al tolerance, especially for the P-efficient genotype HN89. Subsequent hydroponic studies demonstrated that solution pH, Al, and P levels coordinately altered soybean (Glycine max) root growth and malate exudation. Interestingly, HN89 released more malate under conditions mimicking acid soils (low pH, +P, and +Al), suggesting that root malate exudation might be critical for soybean adaptation to both Al toxicity and P deficiency on acid soils. GmALMT1, a soybean malate transporter gene, was cloned from the Al-treated root tips of HN89. Like root malate exudation, GmALMT1 expression was also pH dependent, being suppressed by low pH but enhanced by Al plus P addition in roots of HN89. Quantitative real-time PCR, transient expression of a GmALMT1-yellow fluorescent protein chimera in Arabidopsis protoplasts, and electrophysiological analysis of Xenopus laevis oocytes expressing GmALMT1 demonstrated that GmALMT1 encodes a root cell plasma membrane transporter that mediates malate efflux in an extracellular pH-dependent and Al-independent manner. Overexpression of GmALMT1 in transgenic Arabidopsis, as well as overexpression and knockdown of GmALMT1 in transgenic soybean hairy roots, indicated that GmALMT1-mediated root malate efflux does underlie soybean Al tolerance. Taken together, our results suggest that malate exudation is an important component of soybean adaptation to acid soils and is coordinately regulated by three factors, pH, Al, and P, through the regulation of GmALMT1 expression and GmALMT1 function. PMID:23341359

  20. Direct conversion of glucose to malate by synthetic metabolic engineering.

    PubMed

    Ye, Xiaoting; Honda, Kohsuke; Morimoto, Yumi; Okano, Kenji; Ohtake, Hisao

    2013-03-10

    Synthetic metabolic engineering enables us to construct an in vitro artificial synthetic pathways specialized for chemical manufacturing through the simple heat-treatment of the recombinant mesophiles having thermophilic enzymes, followed by rational combination of those biocatalytic modules. In this work, we constructed a synthetic pathway capable of direct conversion of glucose to malate. The reversible carboxylation of pyruvate catalyzed by a malic enzyme derived from Thermococcus kodakarensis (TkME) (ΔG°'=+7.3kJmol(-1)) was coupled with a thermodynamically favorable non-ATP-forming Embden-Meyerhof pathway to balance the consumption and regeneration of redox cofactors and to shift the overall equilibrium toward malate production (glucose+2HCO3(-)+2H→2 malate+2H2O; ΔG°'=-121.4kJmol(-1)). TkME exhibited both pyruvate carboxylation (malate-forming) and pyruvate reduction (lactate-forming) activities. By increasing HCO3(-) concentration, the reaction specificity could be redirected to malate production. As a result, the direct conversion of glucose to malate was achieved with a molar yield of 60%.

  1. Structural properties of a-Si films and their effect on aluminum induced crystallization

    SciTech Connect

    Tankut, Aydin; Ozkol, Engin; Karaman, Mehmet; Turan, Rasit; Canli, Sedat

    2015-10-15

    In this paper, we report the influence of the structural properties of amorphous silicon (a-Si) on its subsequent crystallization behavior via the aluminum induced crystallization (AIC) method. Two distinct a-Si deposition techniques, electron beam evaporation and plasma enhanced chemical vapor deposition (PECVD), are compared for their effect on the overall AIC kinetics as well as the properties of the final poly-crystalline (poly-Si) silicon film. Raman and FTIR spectroscopy results indicate that the PECVD grown a-Si films has higher intermediate-range order, which is enhanced for increased hydrogen dilution during deposition. With increasing intermediate-range order of the a-Si, the rate of AIC is diminished, leading larger poly-Si grain size.

  2. l-Malate Production by Metabolically Engineered Escherichia coli▿ †

    PubMed Central

    Zhang, X.; Wang, X.; Shanmugam, K. T.; Ingram, L. O.

    2011-01-01

    Escherichia coli strains (KJ060 and KJ073) that were previously developed for succinate production have now been modified for malate production. Many unexpected changes were observed during this investigation. The initial strategy of deleting fumarase isoenzymes was ineffective, and succinate continued to accumulate. Surprisingly, a mutation in fumarate reductase alone was sufficient to redirect carbon flow into malate even in the presence of fumarase. Further deletions were needed to inactivate malic enzymes (typically gluconeogenic) and prevent conversion to pyruvate. However, deletion of these genes (sfcA and maeB) resulted in the unexpected accumulation of d-lactate despite the prior deletion of mgsA and ldhA and the absence of apparent lactate dehydrogenase activity. Although the metabolic source of this d-lactate was not identified, lactate accumulation was increased by supplementation with pyruvate and decreased by the deletion of either pyruvate kinase gene (pykA or pykF) to reduce the supply of pyruvate. Many of the gene deletions adversely affected growth and cell yield in minimal medium under anaerobic conditions, and volumetric rates of malate production remained low. The final strain (XZ658) produced 163 mM malate, with a yield of 1.0 mol (mol glucose−1), half of the theoretical maximum. Using a two-stage process (aerobic cell growth and anaerobic malate production), this engineered strain produced 253 mM malate (34 g liter−1) within 72 h, with a higher yield (1.42 mol mol−1) and productivity (0.47 g liter−1 h−1). This malate yield and productivity are equal to or better than those of other known biocatalysts. PMID:21097588

  3. Malate Synthesis and Secretion Mediated by a Manganese-Enhanced Malate Dehydrogenase Confers Superior Manganese Tolerance in Stylosanthes guianensis1

    PubMed Central

    Chen, Zhijian; Sun, Lili; Liu, Pandao; Liu, Guodao; Tian, Jiang; Liao, Hong

    2015-01-01

    Manganese (Mn) toxicity is a major constraint limiting plant growth on acidic soils. Superior Mn tolerance in Stylosanthes spp. has been well documented, but its molecular mechanisms remain largely unknown. In this study, superior Mn tolerance in Stylosanthes guianensis was confirmed, as reflected by a high Mn toxicity threshold. Furthermore, genetic variation of Mn tolerance was evaluated using two S. guianensis genotypes, which revealed that the Fine-stem genotype had higher Mn tolerance than the TPRC2001-1 genotype, as exhibited through less reduction in dry weight under excess Mn, and accompanied by lower internal Mn concentrations. Interestingly, Mn-stimulated increases in malate concentrations and exudation rates were observed only in the Fine-stem genotype. Proteomic analysis of Fine-stem roots revealed that S. guianensis Malate Dehydrogenase1 (SgMDH1) accumulated in response to Mn toxicity. Western-blot and quantitative PCR analyses showed that Mn toxicity resulted in increased SgMDH1 accumulation only in Fine-stem roots, but not in TPRC2001-1. The function of SgMDH1-mediated malate synthesis was verified through in vitro biochemical analysis of SgMDH1 activities against oxaloacetate, as well as in vivo increased malate concentrations in yeast (Saccharomyces cerevisiae), soybean (Glycine max) hairy roots, and Arabidopsis (Arabidopsis thaliana) with SgMDH1 overexpression. Furthermore, SgMDH1 overexpression conferred Mn tolerance in Arabidopsis, which was accompanied by increased malate exudation and reduced plant Mn concentrations, suggesting that secreted malate could alleviate Mn toxicity in plants. Taken together, we conclude that the superior Mn tolerance of S. guianensis is achieved by coordination of internal and external Mn detoxification through malate synthesis and exudation, which is regulated by SgMDH1 at both transcription and protein levels. PMID:25378694

  4. Malate dehydrogenase isozymes in the longnose dace, Rhinichthys cataractae.

    PubMed

    Starzyk, R M; Merritt, R B

    1980-08-01

    The interspecies homology of dace supernatant (A2,AB,B2) and mitochondrial (C2) malate dehydrogenase isozymes has been established through cell fractionation and tissue distribution studies. Isolated supernatant malate dehydrogenase (s-MDH) isozymes show significant differences in Michaelis constants for oxaloacetate and in pH optima. Shifts in s-MDH isozyme pH optima with temperature may result in immediate compensation for increase in ectotherm body pH with decrease in temperature, but duplicate s-MDH isozymes are probably maintained through selection for tissue specific regulation of metabolism.

  5. Optimal dose of zinc supplementation for preventing aluminum-induced neurotoxicity in rats

    PubMed Central

    Lu, Hao; Hu, Jianyang; Li, Jing; Pang, Wei; Hu, Yandan; Yang, Hongpeng; Li, Wenjie; Huang, Chengyu; Zhang, Mingman; Jiang, Yugang

    2013-01-01

    Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed a diet containing different doses of zinc (50, 100, 200 mg/kg) for 9 weeks, and orally administered aluminum chloride (300 mg/kg daily) from the third week for 7 consecutive weeks. Open-field behavioral test results showed that the number of rearings in the group given the 100 mg/kg zinc supplement was significantly increased compared with the group given the 50 mg/kg zinc supplement. Malondialdehyde content in the cerebrum was significantly decreased, while dopamine and 5-hydroxytryptamine levels were increased in the groups given the diet supplemented with 100 and 200 mg/kg zinc, compared with the group given the diet supplemented with 50 mg/kg zinc. The acetylcholinesterase activity in the cerebrum was significantly decreased in the group given the 100 mg/kg zinc supplement. Hematoxylin-eosin staining revealed evident pathological damage in the hippocampus of rats in the group given the diet supplemented with 50 mg/kg zinc, but the damage was attenuated in the groups given the diet supplemented with 100 and 200 mg/kg zinc. Our findings suggest that zinc is a potential neuroprotective agent against aluminum-induced neurotoxicity in rats, and the optimal dosages are 100 and 200 mg/kg. PMID:25206586

  6. Silencing of Long Non-Coding RNA MALAT1 Promotes Apoptosis of Glioma Cells

    PubMed Central

    2016-01-01

    The metastasis-associated lung adenocarcinoma transcription 1 (MALAT1) is a highly conserved long non-coding RNA (lncRNA) gene. However, little is known about the pathological role of lncRNA MALAT1 in glioma. In the present study, we explored the expression level of lncRNA MALAT1 in primary glioma tissues as well as in U87 and U251 glioma cell lines. Using qRT-PCR, we found that the expression of lncRNA MALAT1 was significantly increased in glioma tissues compared with that of paracancerous tissues. Meanwhile, the expression of MALAT1 was highly expressed in U98 and U251 cells. In order to explore the function of MALAT1, the expression of MALAT1 was greatly reduced in U87 and U251 cells transfected with siRNA specifically targeting MALAT1. Consequently, cell viability of U87 and U251 cells were drastically decreased after the knockdown of MALAT1. Concomitantly, the apoptosis rate of the two cell lines was dramatically increased. Furthermore, the expression levels of some tumor markers were reduced after the knockdown of MALAT1, such as CCND1 and MYC. In summary, the current study indicated a promoting role of MALAT1 in the development of glioma cell. PMID:27134488

  7. The role of Allium cepa on aluminum-induced reproductive dysfunction in experimental male rat models

    PubMed Central

    Ige, Serah F; Akhigbe, Roland E

    2012-01-01

    AIM: Reproductive toxicity is a major challenge associated with aluminum (Al) exposure. Studies that associated Al with reproductive dysfunction did not account for the possible influence of Allium cepa extract. This study, therefore, investigates the influence of A. cepa on aluminum-induced reproductive dysfunction. MATERIALS AND METHODS: Six male rats per group were assigned to one of the following four treatment groups: The control animals were on control diet. A. cepa-treated rats received 1 ml of the extract/100 g body weight (BW), Al-treated rats received 100 mg AlCl3 /kg BW, and A.cepa+Al received 1 ml of the extract/100 g BW plus 100 mg AlCl3 /kg BW. Rats were orally administered their respective doses. A. cepa treatment was for 8 weeks, while Al treatment was for the last 3 days of the experimental period. RESULTS: Results obtained showed that Al significantly decreased (P < 0.05) plasma testosterone, follicular stimulating hormone (FSH), luteinizing hormone (LH), sperm count, motility, morphology and viability, superoxide dismutase (SOD) and catalase (CAT) activities, while lipid peroxidation index [malondialdehyde (MDA)] was significantly (P < 0.05) increased. Reproductive hormones (except testosterone), sperm qualities, and enzymatic antioxidants were significantly (P < 0.05) increased in A. cepa-treated rats and A. cepa plus Al-treated rats, while MDA was significantly (P < 0.05) improved. Weights of testes were comparable in all groups. CONCLUSION: It is thus suggested that Al exerts reproductive dysfunction by oxidative damage. A. cepa antagonizes the toxic effects of AlCl3 and improves the antioxidant status and sperm quality of male rat. However, testosterone level did not increase with A. cepa treatment. PMID:23162360

  8. Poly-crystalline thin-film by aluminum induced crystallization on aluminum nitride substrate

    NASA Astrophysics Data System (ADS)

    Bhopal, Muhammad Fahad; Lee, Doo Won; Lee, Soo Hong

    2016-09-01

    Thin-film polycrystalline silicon ( pc-Si) on foreign (non-silicon) substrates has been researched by various research groups for the production of photovoltaic cells. High quality pc-Si deposition on foreign substrates with superior optical properties is considered to be the main hurdle in cell fabrication. Metal induced crystallization (MIC) is one of the renowned techniques used to produce this quality of material. In the current study, an aluminum induced crystallization (AIC) method was adopted to produce pc-Si thin-film on aluminum nitride (AlN) substrate by a seed layer approach. Aluminum and a-Si layer were deposited using an e-beam evaporator. Various annealing conditions were used in order to investigate the AIC grown pc-Si seed layers for process optimization. The effect of thermal annealing on grain size, defects preferentially crystallographic orientation of the grains were analyzed. Surface morphology was studied using an optical microscope. Poly-silicon film with a crystallinity fraction between 95-100% and an FWHM between 5-6 cm-1 is achievable at low temperatures and for short time intervals. A grain size of about 10 micron can be obtained at a low deposition rate on an AIN substrate. Similarly, Focused ion beam (FIB) also showed that at 425 °C sample B and at 400 °C sample A were fully crystallized. The crystalline quality of pc-Si was evaluated using μ-Raman spectroscopy as a function of annealed conditions and Grazing incidence X-ray diffraction (GIXRD) was used to determine the phase direction of the pc-Si layer. The current study implicates that a poly-silicon layer with good crystallographic orientation and crystallinity fraction is achievable on AIN substrate at low temperatures and short time frames.

  9. Prognostic value of a newly identified MALAT1 alternatively spliced transcript in breast cancer

    PubMed Central

    Meseure, Didier; Vacher, Sophie; Lallemand, François; Alsibai, Kinan Drak; Hatem, Rana; Chemlali, Walid; Nicolas, Andre; De Koning, Leanne; Pasmant, Eric; Callens, Celine; Lidereau, Rosette; Morillon, Antonin; Bieche, Ivan

    2016-01-01

    Background: Epigenetic deregulation is considered as a new hallmark of cancer. The long non-coding RNA MALAT1 has been implicated in several cancers; however, its role in breast cancer is still little known. Methods: We used RT–PCR, in situ hybridisation, and RPPA methods to quantify (i) the full-length (FL) and an alternatively spliced variant (Δsv) of MALAT1, and (ii) a panel of transcripts and proteins involved in MALAT1 pathways, in a large series of breast tumours from patients with known clinical/pathological status and long-term outcome. Results: MALAT1 was overexpressed in 14% (63/446) of the breast tumours. MALAT1-overexpressed tumour epithelial cells showed marked diffuse nuclear signals and numerous huge nuclear speckles. Screening of the dbEST database led to the identification of Δsv-MALAT1, a major alternatively spliced MALAT1 transcript, with a very different expression pattern compared with FL-MALAT1. This alternative Δsv-MALAT1 transcript was mainly underexpressed (18.8%) in our breast tumour series. Multivariate analysis showed that alternative Δsv-MALAT1 transcript is an independent prognostic factor. Δsv-MALAT1 expression was associated with alterations of the pre-mRNAs alternative splicing machinery, and of the Drosha-DGCR8 complex required for non-coding RNA biogenesis. Alternative Δsv-MALAT1 transcript expression was associated to YAP protein status and with an activation of the PI3K-AKT pathway. Conclusions: Our results reveal a complex expression pattern of various MALAT1 transcript variants in breast tumours, and suggest that this pattern of expressions should be taken into account to evaluate MALAT1 as predictive biomarker and therapeutic target. PMID:27172249

  10. Malate as a key carbon source of leaf dark-respired CO2 across different environmental conditions in potato plants

    PubMed Central

    Lehmann, Marco M.; Rinne, Katja T.; Blessing, Carola; Siegwolf, Rolf T. W.; Buchmann, Nina; Werner, Roland A.

    2015-01-01

    Dissimilation of carbon sources during plant respiration in support of metabolic processes results in the continuous release of CO2. The carbon isotopic composition of leaf dark-respired CO2 (i.e. δ 13 C R) shows daily enrichments up to 14.8‰ under different environmental conditions. However, the reasons for this 13C enrichment in leaf dark-respired CO2 are not fully understood, since daily changes in δ13C of putative leaf respiratory carbon sources (δ 13 C RS) are not yet clear. Thus, we exposed potato plants (Solanum tuberosum) to different temperature and soil moisture treatments. We determined δ 13 C R with an in-tube incubation technique and δ 13 C RS with compound-specific isotope analysis during a daily cycle. The highest δ 13 C RS values were found in the organic acid malate under different environmental conditions, showing less negative values compared to δ 13 C R (up to 5.2‰) and compared to δ 13 C RS of soluble carbohydrates, citrate and starch (up to 8.8‰). Moreover, linear relationships between δ 13 C R and δ 13 C RS among different putative carbon sources were strongest for malate during daytime (r2=0.69, P≤0.001) and nighttime (r2=0.36, P≤0.001) under all environmental conditions. A multiple linear regression analysis revealed δ 13 C RS of malate as the most important carbon source influencing δ 13 C R. Thus, our results strongly indicate malate as a key carbon source of 13C enriched dark-respired CO2 in potato plants, probably driven by an anapleurotic flux replenishing intermediates of the Krebs cycle. PMID:26139821

  11. Malate as a key carbon source of leaf dark-respired CO2 across different environmental conditions in potato plants.

    PubMed

    Lehmann, Marco M; Rinne, Katja T; Blessing, Carola; Siegwolf, Rolf T W; Buchmann, Nina; Werner, Roland A

    2015-09-01

    Dissimilation of carbon sources during plant respiration in support of metabolic processes results in the continuous release of CO2. The carbon isotopic composition of leaf dark-respired CO2 (i.e. δ (13) C R ) shows daily enrichments up to 14.8‰ under different environmental conditions. However, the reasons for this (13)C enrichment in leaf dark-respired CO2 are not fully understood, since daily changes in δ(13)C of putative leaf respiratory carbon sources (δ (13) C RS ) are not yet clear. Thus, we exposed potato plants (Solanum tuberosum) to different temperature and soil moisture treatments. We determined δ (13) C R with an in-tube incubation technique and δ (13) C RS with compound-specific isotope analysis during a daily cycle. The highest δ (13) C RS values were found in the organic acid malate under different environmental conditions, showing less negative values compared to δ (13) C R (up to 5.2‰) and compared to δ (13) C RS of soluble carbohydrates, citrate and starch (up to 8.8‰). Moreover, linear relationships between δ (13) C R and δ (13) C RS among different putative carbon sources were strongest for malate during daytime (r(2)=0.69, P≤0.001) and nighttime (r(2)=0.36, P≤0.001) under all environmental conditions. A multiple linear regression analysis revealed δ (13) C RS of malate as the most important carbon source influencing δ (13) C R . Thus, our results strongly indicate malate as a key carbon source of (13)C enriched dark-respired CO2 in potato plants, probably driven by an anapleurotic flux replenishing intermediates of the Krebs cycle.

  12. Convergent evolution of Trichomonas vaginalis lactate dehydrogenase from malate dehydrogenase

    PubMed Central

    Wu, Gang; Fiser, András; ter Kuile, Benno; Šali, Andrej; Müller, Miklós

    1999-01-01

    Lactate dehydrogenase (LDH) is present in the amitochondriate parasitic protist Trichomonas vaginalis and some but not all other trichomonad species. The derived amino acid sequence of T. vaginalis LDH (TvLDH) was found to be more closely related to the cytosolic malate dehydrogenase (MDH) of the same species than to any other LDH. A key difference between the two T. vaginalis sequences was that Arg91 of MDH, known to be important in coordinating the C-4 carboxyl of oxalacetate/malate, was replaced by Leu91 in LDH. The change Leu91Arg by site-directed mutagenesis converted TvLDH into an MDH. The reverse single amino acid change Arg91Leu in TvMDH, however, gave a product with no measurable LDH activity. Phylogenetic reconstructions indicate that TvLDH arose from an MDH relatively recently. PMID:10339579

  13. Sp1 cooperates with Sp3 to upregulate MALAT1 expression in human hepatocellular carcinoma.

    PubMed

    Huang, Ziling; Huang, Lanshan; Shen, Siqiao; Li, Jia; Lu, Huiping; Mo, Weijia; Dang, Yiwu; Luo, Dianzhong; Chen, Gang; Feng, Zhenbo

    2015-11-01

    Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), also known as nuclear-enriched transcript 2 (NEAT2), is highly conserved among mammals and highly expressed in the nucleus. It was first identified in lung cancer as a prognostic marker for metastasis but is also associated with several other solid tumors. In hepatocellular carcinoma (HCC), MALAT1 is a novel biomarker for predicting tumor recurrence after liver transplantation. The mechanism of overexpression in tumor progression remains unclear. In the present study, we investigated the role of specificity protein 1/3 (Sp1/3) in regulation of MALAT1 transcription in HCC cells. The results showed a high expression of Sp1, Sp3 and MALAT1 in HCC vs. paired non-tumor liver tissues, which was associated with the AFP level (Sp1, r=7.44, P=0.0064; MALAT1, r=12.37, P=0.0004). Co-silencing of Sp1 and Sp3 synergistically repressed MALAT1 expression. Sp1 binding inhibitor, mithramycin A (MIT), also inhibited MALAT1 expression in HCC cells. In conclusion, the upstream of MALAT1 contains five Sp1/3 binding sites, which may be responsible for MALAT1 transcription. Inhibitors, such as MIT, provide a potential therapeutic strategy for HCC patients with MALAT1 overexpression.

  14. Long noncoding RNA MALAT1 as a potential therapeutic target in osteosarcoma.

    PubMed

    Cai, Xianyi; Liu, Yunlu; Yang, Wen; Xia, Yun; Yang, Cao; Yang, Shuhua; Liu, Xianzhe

    2016-06-01

    Recent studies have revealed that long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays an important role in the development of several solid tumors. However, the function of MALAT1 in the tumorigenesis of osteosarcoma remains unknown. In the present study, levels of MALAT1 in human osteosarcoma cell lines and tissues were detected by quantitative real-time polymerase chain reaction (RT-PCR). The roles of MALAT1 in osteosarcoma were investigated by using in vitro and in vivo assays. We observed that MALAT1 expression was up-regulated in human osteosarcoma cell lines and tissues. In vitro knockdown of MALAT1 by siRNA significantly inhibited cell proliferation and migration, and induced cell cycle arrest and apoptosis in osteosarcoma cells. In addition, MALAT1 knockdown markedly suppressed the formation of tubular network structures and caused breakage of stress fibers in osteosarcoma cell lines U2OS and MNNG/HOS. Furthermore, MALAT1 knockdown delayed tumor growth in an osteosarcoma xenograft model. Specifically, we found that administration of MALAT1 siRNA decreased the protein levels of RhoA and its downstream effectors Rho-associated coiled-coil containing protein kinases (ROCKs). Taken together, these findings suggest that MALAT1 plays an oncogenic role in osteosarcoma and may be a promising therapeutic target for the treatment of osteosarcoma patients. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:932-941, 2016.

  15. Metabolic Fate of the Carboxyl Groups of Malate and Pyruvate and their Influence on δ13C of Leaf-Respired CO2 during Light Enhanced Dark Respiration

    PubMed Central

    Lehmann, Marco M.; Wegener, Frederik; Barthel, Matti; Maurino, Veronica G.; Siegwolf, Rolf T. W.; Buchmann, Nina; Werner, Christiane; Werner, Roland A.

    2016-01-01

    The enhanced CO2 release of illuminated leaves transferred into darkness, termed “light enhanced dark respiration (LEDR)”, is often associated with an increase in the carbon isotope ratio of the respired CO2 (δ13CLEDR). The latter has been hypothesized to result from different respiratory substrates and decarboxylation reactions in various metabolic pathways, which are poorly understood so far. To provide a better insight into the underlying metabolic processes of δ13CLEDR, we fed position-specific 13C-labeled malate and pyruvate via the xylem stream to leaves of species with high and low δ13CLEDR values (Halimium halimifolium and Oxalis triangularis, respectively). During respective label application, we determined label-derived leaf 13CO2 respiration using laser spectroscopy and the 13C allocation to metabolic fractions during light–dark transitions. Our results clearly show that both carboxyl groups (C-1 and C-4 position) of malate similarly influence respiration and metabolic fractions in both species, indicating possible isotope randomization of the carboxyl groups of malate by the fumarase reaction. While C-2 position of pyruvate was only weakly respired, the species-specific difference in natural δ13CLEDR patterns were best reflected by the 13CO2 respiration patterns of the C-1 position of pyruvate. Furthermore, 13C label from malate and pyruvate were mainly allocated to amino and organic acid fractions in both species and only little to sugar and lipid fractions. In summary, our results suggest that respiration of both carboxyl groups of malate (via fumarase) by tricarboxylic acid cycle reactions or by NAD-malic enzyme influences δ13CLEDR. The latter supplies the pyruvate dehydrogenase reaction, which in turn determines natural δ13CLEDR pattern by releasing the C-1 position of pyruvate. PMID:27375626

  16. The BnALMT1 and BnALMT2 genes from rape encode aluminum-activated malate transporters that enhance the aluminum resistance of plant cells.

    PubMed

    Ligaba, Ayalew; Katsuhara, Maki; Ryan, Peter R; Shibasaka, Mineo; Matsumoto, Hideaki

    2006-11-01

    The release of organic anions from roots can protect plants from aluminum (Al) toxicity and help them overcome phosphorus (P) deficiency. Our previous findings showed that Al treatment induced malate and citrate efflux from rape (Brassica napus) roots, and that P deficiency did not induce the efflux. Since this response is similar to the malate efflux from wheat (Triticum aestivum) that is controlled by the TaALMT1 gene, we investigated whether homologs of TaALMT1 are present in rape and whether they are involved in the release of organic anions. We isolated two TaALMT1 homologs from rape designated BnALMT1 and BnALMT2 (B. napus Al-activated malate transporter). The expression of these genes was induced in roots, but not shoots, by Al treatment but P deficiency had no effect. Several other cations (lanthanum, ytterbium, and erbium) also increased BnALMT1 and BnALMT2 expression in the roots. The function of the BnALMT1 and BnALMT2 proteins was investigated by heterologous expression in cultured tobacco (Nicotiana tabacum) cells and in Xenopus laevis oocytes. Both transfection systems showed an enhanced capacity for malate efflux but not citrate efflux, when exposed to Al. Smaller malate fluxes were also activated by ytterbium and erbium treatment. Transgenic tobacco cells grew significantly better than control cells following an 18 h treatment with Al, indicating that the expression of BnALMT1 and BnALMT2 increased the resistance of these plant cells to Al stress. This report demonstrates that homologs of the TaALMT1 gene from wheat perform similar functions in other species.

  17. Metabolic Fate of the Carboxyl Groups of Malate and Pyruvate and their Influence on δ(13)C of Leaf-Respired CO2 during Light Enhanced Dark Respiration.

    PubMed

    Lehmann, Marco M; Wegener, Frederik; Barthel, Matti; Maurino, Veronica G; Siegwolf, Rolf T W; Buchmann, Nina; Werner, Christiane; Werner, Roland A

    2016-01-01

    The enhanced CO2 release of illuminated leaves transferred into darkness, termed "light enhanced dark respiration (LEDR)", is often associated with an increase in the carbon isotope ratio of the respired CO2 (δ(13)CLEDR). The latter has been hypothesized to result from different respiratory substrates and decarboxylation reactions in various metabolic pathways, which are poorly understood so far. To provide a better insight into the underlying metabolic processes of δ(13)CLEDR, we fed position-specific (13)C-labeled malate and pyruvate via the xylem stream to leaves of species with high and low δ(13)CLEDR values (Halimium halimifolium and Oxalis triangularis, respectively). During respective label application, we determined label-derived leaf (13)CO2 respiration using laser spectroscopy and the (13)C allocation to metabolic fractions during light-dark transitions. Our results clearly show that both carboxyl groups (C-1 and C-4 position) of malate similarly influence respiration and metabolic fractions in both species, indicating possible isotope randomization of the carboxyl groups of malate by the fumarase reaction. While C-2 position of pyruvate was only weakly respired, the species-specific difference in natural δ(13)CLEDR patterns were best reflected by the (13)CO2 respiration patterns of the C-1 position of pyruvate. Furthermore, (13)C label from malate and pyruvate were mainly allocated to amino and organic acid fractions in both species and only little to sugar and lipid fractions. In summary, our results suggest that respiration of both carboxyl groups of malate (via fumarase) by tricarboxylic acid cycle reactions or by NAD-malic enzyme influences δ(13)CLEDR. The latter supplies the pyruvate dehydrogenase reaction, which in turn determines natural δ(13)CLEDR pattern by releasing the C-1 position of pyruvate. PMID:27375626

  18. Folding of malate dehydrogenase inside the GroEL-GroES cavity.

    PubMed

    Chen, J; Walter, S; Horwich, A L; Smith, D L

    2001-08-01

    The chaperonin GroEL binds nonnative substrate protein in the hydrophobic central cavity of an open ring. ATP and GroES binding to the same ring converts this cavity into an encapsulated, hydrophilic chamber that mediates productive folding. A 'rack' mechanism of initial protein unfolding proposes that, upon GroES and ATP binding, the polypeptide is stretched between the binding sites on the twisting apical domains of GroEL before complete release into the chamber. Here, the structure of malate dehydrogenase (MDH) subunit during folding is monitored by deuterium exchange, peptic fragment production and mass spectrometry. When bound to GroEL, MDH exhibits a core of partially protected secondary structure that is only modestly deprotected upon ATP and GroES binding. Moreover, deprotection is broadly distributed throughout MDH, suggesting that it results from breaking hydrogen bonds between MDH and the cavity wall or global destabilization, as opposed to forced mechanical unfolding.

  19. Hypoxia upregulates Malat1 expression through a CaMKK/AMPK/HIF-1α axis.

    PubMed

    Sallé-Lefort, Sandrine; Miard, Stéphanie; Nolin, Marc-André; Boivin, Louise; Paré, Marie-Ève; Debigaré, Richard; Picard, Frédéric

    2016-10-01

    Increased expression levels of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (Malat1) have been associated with enhanced proliferation and metastasis of several cancer cell types. Hypoxia, a hallmark characteristic of solid tumors, has been linked to an increase in the activity of the ATP-generating AMPK protein. Since Malat1 was recently shown to be upregulated during hypoxia, the objective of this study was to determine the contribution of AMPK in the mechanistic pathways regulating Malat1 expression in low oxygen conditions. Compared to those cultured in 21% O2 conditions, HeLa cells incubated in 1.5% O2 expressed more Malat1 transcripts. This observation was mimicked in HEK293T cells using a synthetic reporter construct containing 5.6 kb of the human Malat1 promoter, suggesting that hypoxia directly impacted Malat1 gene transcription. Interestingly, pharmacological stimulation of AMPK increased Malat1 promoter transactivation in 21% O2 conditions, whereas inhibition of either AMPK or its upstream activator CaMKK completely abolished the augmentation of Malat1 under hypoxia. Pharmacological modulation of LKB1, another major regulator of AMPK, had no impact on Malat1 promoter transactivation, suggesting that calcium inputs are important in the control of Malat1 expression by AMPK. Overexpression of hypoxia-inducible factor-1α (HIF-1α) increased Malat1 expression in 21% O2 conditions, whereas pharmacological inhibition of HIF-1α blocked the impact of hypoxia on the Malat1 promoter. Taken together, these findings strongly suggest that Malat1 expression is regulated in hypoxic conditions by a CaMKK/AMPK/HIF-1α axis. More research is needed in physiological settings to test the clinical relevance of this pathway.

  20. Hypoxia upregulates Malat1 expression through a CaMKK/AMPK/HIF-1α axis.

    PubMed

    Sallé-Lefort, Sandrine; Miard, Stéphanie; Nolin, Marc-André; Boivin, Louise; Paré, Marie-Ève; Debigaré, Richard; Picard, Frédéric

    2016-10-01

    Increased expression levels of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (Malat1) have been associated with enhanced proliferation and metastasis of several cancer cell types. Hypoxia, a hallmark characteristic of solid tumors, has been linked to an increase in the activity of the ATP-generating AMPK protein. Since Malat1 was recently shown to be upregulated during hypoxia, the objective of this study was to determine the contribution of AMPK in the mechanistic pathways regulating Malat1 expression in low oxygen conditions. Compared to those cultured in 21% O2 conditions, HeLa cells incubated in 1.5% O2 expressed more Malat1 transcripts. This observation was mimicked in HEK293T cells using a synthetic reporter construct containing 5.6 kb of the human Malat1 promoter, suggesting that hypoxia directly impacted Malat1 gene transcription. Interestingly, pharmacological stimulation of AMPK increased Malat1 promoter transactivation in 21% O2 conditions, whereas inhibition of either AMPK or its upstream activator CaMKK completely abolished the augmentation of Malat1 under hypoxia. Pharmacological modulation of LKB1, another major regulator of AMPK, had no impact on Malat1 promoter transactivation, suggesting that calcium inputs are important in the control of Malat1 expression by AMPK. Overexpression of hypoxia-inducible factor-1α (HIF-1α) increased Malat1 expression in 21% O2 conditions, whereas pharmacological inhibition of HIF-1α blocked the impact of hypoxia on the Malat1 promoter. Taken together, these findings strongly suggest that Malat1 expression is regulated in hypoxic conditions by a CaMKK/AMPK/HIF-1α axis. More research is needed in physiological settings to test the clinical relevance of this pathway. PMID:27499160

  1. Stringency of substrate specificity of Escherichia coli malate dehydrogenase.

    SciTech Connect

    Boernke, W. E.; Millard, C. S.; Stevens, P. W.; Kakar, S. N.; Stevens, F. J.; Donnelly, M. I.; Nebraska Wesleyan Univ.

    1995-09-10

    Malate dehydrogenase and lactate dehydrogenase are members of the structurally and functionally homologous family of 2-ketoacid dehydrogenases. Both enzymes display high specificity for their respective keto substrates, oxaloacetate and pyruvate. Closer analysis of their specificity, however, reveals that the specificity of malate dehydrogenase is much stricter and less malleable than that of lactate dehydrogenase. Site-specific mutagenesis of the two enzymes in an attempt to reverse their specificity has met with contrary results. Conversion of a specific active-site glutamine to arginine in lactate dehydrogenase from Bacillus stearothermophilus generated an enzyme that displayed activity toward oxaloacetate equal to that of the native enzyme toward pyruvate (H. M. Wilks et al. (1988) Science 242, 1541-1544). We have constructed a series of mutants in the mobile, active site loop of the Escherichia coli malate dehydrogenase that incorporate the complementary change, conversion of arginine 81 to glutamine, to evaluate the role of charge distribution and conformational flexibility within this loop in defining the substrate specificity of these enzymes. Mutants incorporating the change R81Q all had reversed specificity, displaying much higher activity toward pyruvate than to the natural substrate, oxaloacetate. In contrast to the mutated lactate dehydrogenase, these reversed-specificity mutants were much less active than the native enzyme. Secondary mutations within the loop of the E. coli enzyme (A80N, A80P, A80P/M85E/D86T) had either no or only moderately beneficial effects on the activity of the mutant enzyme toward pyruvate. The mutation A80P, which can be expected to reduce the overall flexibility of the loop, modestly improved activity toward pyruvate. The possible physiological relevance of the stringent specificity of malate dehydrogenase was investigated. In normal strains of E. coli, fermentative metabolism was not affected by expression of the mutant

  2. Multiple strategies to prevent oxidative stress in Arabidopsis plants lacking the malate valve enzyme NADP-malate dehydrogenase.

    PubMed

    Hebbelmann, Inga; Selinski, Jennifer; Wehmeyer, Corinna; Goss, Tatjana; Voss, Ingo; Mulo, Paula; Kangasjärvi, Saijaliisa; Aro, Eva-Mari; Oelze, Marie-Luise; Dietz, Karl-Josef; Nunes-Nesi, Adriano; Do, Phuc T; Fernie, Alisdair R; Talla, Sai K; Raghavendra, Agepati S; Linke, Vera; Scheibe, Renate

    2012-02-01

    The nuclear-encoded chloroplast NADP-dependent malate dehydrogenase (NADP-MDH) is a key enzyme controlling the malate valve, to allow the indirect export of reducing equivalents. Arabidopsis thaliana (L.) Heynh. T-DNA insertion mutants of NADP-MDH were used to assess the role of the light-activated NADP-MDH in a typical C(3) plant. Surprisingly, even when exposed to high-light conditions in short days, nadp-mdh knockout mutants were phenotypically indistinguishable from the wild type. The photosynthetic performance and typical antioxidative systems, such as the Beck-Halliwell-Asada pathway, were barely affected in the mutants in response to high-light treatment. The reactive oxygen species levels remained low, indicating the apparent absence of oxidative stress, in the mutants. Further analysis revealed a novel combination of compensatory mechanisms in order to maintain redox homeostasis in the nadp-mdh plants under high-light conditions, particularly an increase in the NTRC/2-Cys peroxiredoxin (Prx) system in chloroplasts. There were indications of adjustments in extra-chloroplastic components of photorespiration and proline levels, which all could dissipate excess reducing equivalents, sustain photosynthesis, and prevent photoinhibition in nadp-mdh knockout plants. Such metabolic flexibility suggests that the malate valve acts in concert with other NADPH-consuming reactions to maintain a balanced redox state during photosynthesis under high-light stress in wild-type plants.

  3. A MALAT1/HIF-2α feedback loop contributes to arsenite carcinogenesis

    PubMed Central

    Xu, Yuan; Liu, Yi; Liu, Xinlu; Lu, Lu; Li, Jun; Wang, Qingling; Wei, Shaofeng; Shi, Le; Lu, Xiaolin; Liu, Qizhan; Zhang, Aihua

    2016-01-01

    Arsenic is well established as a human carcinogen, but the molecular mechanisms leading to arsenic-induced carcinogenesis are complex and elusive. It is also not known if lncRNAs are involved in arsenic-induced liver carcinogenesis. We have found that MALAT1, a non-coding RNA, is over-expressed in the sera of people exposed to arsenite and in hepatocellular carcinomas (HCCs), and MALAT1 has a close relation with the clinicopathological characteristics of HCC. In addition, hypoxia-inducible factor (HIF)-2α is up-regulated in HCCs, and MALAT1 and HIF-2α have a positive correlation in HCC tissues. During the malignant transformation of human hepatic epithelial (L-02) cells induced by a low concentration (2.0 μM) of arsenite, MALAT1 and HIF-2α are increased. In addition, arsenite-induced MALAT1 causes disassociation of the von Hippel-Lindau (VHL) protein from HIF-2α, therefore, alleviating VHL-mediated HIF-2α ubiquitination, which causes HIF-2α accumulation. In turn, HIF-2α transcriptionally regulates MALAT1, thus forming a positive feedback loop to ensure expression of arsenite-induced MALAT1 and HIF-2α, which are involved in malignant transformation. Moreover, MALAT1 and HIF-2α promote the invasive and metastatic capacities of arsenite-induced transformed L-02 cells and in HCC-LM3 cells. The capacities of MALAT1 and HIF-2α to promote tumor growth are validated in mouse xenograft models. In mice, arsenite induces an inflammatory response, and MALAT1 and HIF-2α are over-expressed. Together, these findings suggest that the MALAT1/HIF-2α feedback loop is involved in regulation of arsenite-induced malignant transformation. Our results not only confirm a novel mechanism involving reciprocal regulation between MALAT1 and HIF-2α, but also expand the understanding of the carcinogenic potential of arsenite. PMID:26735578

  4. Malic Acid Production by Saccharomyces cerevisiae: Engineering of Pyruvate Carboxylation, Oxaloacetate Reduction, and Malate Export▿ †

    PubMed Central

    Zelle, Rintze M.; de Hulster, Erik; van Winden, Wouter A.; de Waard, Pieter; Dijkema, Cor; Winkler, Aaron A.; Geertman, Jan-Maarten A.; van Dijken, Johannes P.; Pronk, Jack T.; van Maris, Antonius J. A.

    2008-01-01

    Malic acid is a potential biomass-derivable “building block” for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate. This redox- and ATP-neutral, CO2-fixing pathway has a theoretical maximum yield of 2 mol malate (mol glucose)−1. A previously engineered glucose-tolerant, C2-independent pyruvate decarboxylase-negative S. cerevisiae strain was used as the platform to evaluate the impact of individual and combined introduction of three genetic modifications: (i) overexpression of the native pyruvate carboxylase encoded by PYC2, (ii) high-level expression of an allele of the MDH3 gene, of which the encoded malate dehydrogenase was retargeted to the cytosol by deletion of the C-terminal peroxisomal targeting sequence, and (iii) functional expression of the Schizosaccharomyces pombe malate transporter gene SpMAE1. While single or double modifications improved malate production, the highest malate yields and titers were obtained with the simultaneous introduction of all three modifications. In glucose-grown batch cultures, the resulting engineered strain produced malate at titers of up to 59 g liter−1 at a malate yield of 0.42 mol (mol glucose)−1. Metabolic flux analysis showed that metabolite labeling patterns observed upon nuclear magnetic resonance analyses of cultures grown on 13C-labeled glucose were consistent with the envisaged nonoxidative, fermentative pathway for malate production. The engineered strains still produced substantial amounts of pyruvate, indicating that the pathway efficiency can be further improved. PMID:18344340

  5. Malic acid production by Saccharomyces cerevisiae: engineering of pyruvate carboxylation, oxaloacetate reduction, and malate export.

    PubMed

    Zelle, Rintze M; de Hulster, Erik; van Winden, Wouter A; de Waard, Pieter; Dijkema, Cor; Winkler, Aaron A; Geertman, Jan-Maarten A; van Dijken, Johannes P; Pronk, Jack T; van Maris, Antonius J A

    2008-05-01

    Malic acid is a potential biomass-derivable "building block" for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate. This redox- and ATP-neutral, CO(2)-fixing pathway has a theoretical maximum yield of 2 mol malate (mol glucose)(-1). A previously engineered glucose-tolerant, C(2)-independent pyruvate decarboxylase-negative S. cerevisiae strain was used as the platform to evaluate the impact of individual and combined introduction of three genetic modifications: (i) overexpression of the native pyruvate carboxylase encoded by PYC2, (ii) high-level expression of an allele of the MDH3 gene, of which the encoded malate dehydrogenase was retargeted to the cytosol by deletion of the C-terminal peroxisomal targeting sequence, and (iii) functional expression of the Schizosaccharomyces pombe malate transporter gene SpMAE1. While single or double modifications improved malate production, the highest malate yields and titers were obtained with the simultaneous introduction of all three modifications. In glucose-grown batch cultures, the resulting engineered strain produced malate at titers of up to 59 g liter(-1) at a malate yield of 0.42 mol (mol glucose)(-1). Metabolic flux analysis showed that metabolite labeling patterns observed upon nuclear magnetic resonance analyses of cultures grown on (13)C-labeled glucose were consistent with the envisaged nonoxidative, fermentative pathway for malate production. The engineered strains still produced substantial amounts of pyruvate, indicating that the pathway efficiency can be further improved.

  6. Citrulline malate limits increase in muscle fatigue induced by bacterial endotoxins.

    PubMed

    Goubel, F; Vanhoutte, C; Allaf, O; Verleye, M; Gillardin, J M

    1997-03-01

    Citrulline malate is known to improve performance in weakened muscles. The present experiment was designed to test the hypothesis that citrulline malate can limit the effect of endotoxins on muscle fatigability. Endotoxemia was induced in rats by injection of lipopolysaccharides from Klebsiella pneumoniae. Resistance to fatigue was quantified by measuring tension production during repetitive electrical stimulation of the isolated epitrochlearis muscle. Oral treatment by citrulline malate was found to increase resistance to fatigue in infected rats, whereas twitch tension was not modified. This demonstrates the efficacy of citrulline malate for limiting an increase in muscle fatigue elicited with bacterial endotoxins. PMID:9164703

  7. Role of Exogenous Melatonin on Cell Proliferation and Oxidant/Antioxidant System in Aluminum-Induced Renal Toxicity.

    PubMed

    Karabulut-Bulan, Omur; Bayrak, Bertan Boran; Arda-Pirincci, Pelin; Sarikaya-Unal, Guner; Us, Huseyin; Yanardag, Refiye

    2015-11-01

    Aluminum has toxic potential on humans and animals when it accumulates in various tissues. It was shown in a number of studies that aluminum causes oxidative stress by free radical formation and lipid peroxidation in tissues and thus may cause damage in target organs. Although there are numerous studies investigating aluminum toxicity, biochemical mechanisms of the damage caused by aluminum have yet to be explained. Melatonin produced by pineal gland was shown to be an effective antioxidant. Since kidneys are target organs for aluminum accumulation and toxicity, we have studied the role of melatonin against aluminum-induced renal toxicity in rats. Wistar albino rats were divided into five groups. Group I served as control, and received only physiological saline; group II served as positive control for melatonin, and received ethanol and physiological saline; group III received melatonin (10 mg/kg); group IV received aluminum sulfate (5 mg/kg) and group V received aluminum sulfate and melatonin (in the same dose), injected three times a week for 1 month. Administration of aluminum caused degenerative changes in renal tissues, such as increase in metallothionein immunoreactivity and decrease in cell proliferation. Moreover, uric acid and lipid peroxidation levels and xanthine oxidase activity increased, while glutathione, catalase, superoxide dismutase, paraoxonase 1, glucose-6-phosphate dehydrogenase, and sodium potassium ATPase activities decreased. Administration of melatonin mostly prevented these symptoms. Results showed that melatonin is a potential beneficial agent for reducing damage in aluminum-induced renal toxicity.

  8. A domain-based approach for analyzing the function of aluminum-activated malate transporters from wheat (Triticum aestivum) and Arabidopsis thaliana in Xenopus oocytes.

    PubMed

    Sasaki, Takayuki; Tsuchiya, Yoshiyuki; Ariyoshi, Michiyo; Ryan, Peter R; Furuichi, Takuya; Yamamoto, Yoko

    2014-12-01

    Wheat and Arabidopsis plants respond to aluminum (Al) ions by releasing malate from their root apices via Al-activated malate transporter. Malate anions bind with the toxic Al ions and contribute to the Al tolerance of these species. The genes encoding the transporters in wheat and Arabidopsis, TaALMT1 and AtALMT1, respectively, were expressed in Xenopus laevis oocytes and characterized electrophysiologically using the two-electrode voltage clamp system. The Al-activated currents generated by malate efflux were detected for TaALMT1 but not for AtALMT1. Chimeric proteins were generated by swapping the N- and C-terminal halves of TaALMT1 and AtALMT1 (Ta::At and At::Ta). When these chimeras were characterized in oocytes, Al-activated malate efflux was detected for the Ta::At chimera but not for At::Ta, suggesting that the N-terminal half of TaALMT1 is necessary for function in oocytes. An additional chimera, Ta(48)::At, generated by swapping 17 residues from the N-terminus of AtALMT1 with the equivalent 48 residues from TaALMT1, was sufficient to support transport activity. This 48 residue region includes a helical region with a putative transmembrane domain which is absent in AtALMT1. The deletion of this domain from Ta(48)::At led to the complete loss of transport activity. Furthermore, truncations and a deletion at the C-terminal end of TaALMT1 indicated that a putative helical structure in this region was also required for transport function. This study provides insights into the structure-function relationships of Al-activated ALMT proteins by identifying specific domains on the N- and C-termini of TaALMT1 that are critical for basal transport function and Al responsiveness in oocytes.

  9. Reassessment of the Transhydrogenase/Malate Shunt Pathway in Clostridium thermocellum ATCC 27405 through Kinetic Characterization of Malic Enzyme and Malate Dehydrogenase

    PubMed Central

    Taillefer, M.; Rydzak, T.; Levin, D. B.; Oresnik, I. J.

    2015-01-01

    Clostridium thermocellum produces ethanol as one of its major end products from direct fermentation of cellulosic biomass. Therefore, it is viewed as an attractive model for the production of biofuels via consolidated bioprocessing. However, a better understanding of the metabolic pathways, along with their putative regulation, could lead to improved strategies for increasing the production of ethanol. In the absence of an annotated pyruvate kinase in the genome, alternate means of generating pyruvate have been sought. Previous proteomic and transcriptomic work detected high levels of a malate dehydrogenase and malic enzyme, which may be used as part of a malate shunt for the generation of pyruvate from phosphoenolpyruvate. The purification and characterization of the malate dehydrogenase and malic enzyme are described in order to elucidate their putative roles in malate shunt and their potential role in C. thermocellum metabolism. The malate dehydrogenase catalyzed the reduction of oxaloacetate to malate utilizing NADH or NADPH with a kcat of 45.8 s−1 or 14.9 s−1, respectively, resulting in a 12-fold increase in catalytic efficiency when using NADH over NADPH. The malic enzyme displayed reversible malate decarboxylation activity with a kcat of 520.8 s−1. The malic enzyme used NADP+ as a cofactor along with NH4+ and Mn2+ as activators. Pyrophosphate was found to be a potent inhibitor of malic enzyme activity, with a Ki of 0.036 mM. We propose a putative regulatory mechanism of the malate shunt by pyrophosphate and NH4+ based on the characterization of the malate dehydrogenase and malic enzyme. PMID:25616802

  10. Reassessment of the transhydrogenase/malate shunt pathway in Clostridium thermocellum ATCC 27405 through kinetic characterization of malic enzyme and malate dehydrogenase.

    PubMed

    Taillefer, M; Rydzak, T; Levin, D B; Oresnik, I J; Sparling, R

    2015-04-01

    Clostridium thermocellum produces ethanol as one of its major end products from direct fermentation of cellulosic biomass. Therefore, it is viewed as an attractive model for the production of biofuels via consolidated bioprocessing. However, a better understanding of the metabolic pathways, along with their putative regulation, could lead to improved strategies for increasing the production of ethanol. In the absence of an annotated pyruvate kinase in the genome, alternate means of generating pyruvate have been sought. Previous proteomic and transcriptomic work detected high levels of a malate dehydrogenase and malic enzyme, which may be used as part of a malate shunt for the generation of pyruvate from phosphoenolpyruvate. The purification and characterization of the malate dehydrogenase and malic enzyme are described in order to elucidate their putative roles in malate shunt and their potential role in C. thermocellum metabolism. The malate dehydrogenase catalyzed the reduction of oxaloacetate to malate utilizing NADH or NADPH with a kcat of 45.8 s(-1) or 14.9 s(-1), respectively, resulting in a 12-fold increase in catalytic efficiency when using NADH over NADPH. The malic enzyme displayed reversible malate decarboxylation activity with a kcat of 520.8 s(-1). The malic enzyme used NADP(+) as a cofactor along with NH4 (+) and Mn(2+) as activators. Pyrophosphate was found to be a potent inhibitor of malic enzyme activity, with a Ki of 0.036 mM. We propose a putative regulatory mechanism of the malate shunt by pyrophosphate and NH4 (+) based on the characterization of the malate dehydrogenase and malic enzyme.

  11. Preclinical Evidence for the Use of Sunitinib Malate in the Treatment of Plexiform Neurofibromas

    PubMed Central

    Ferguson, Michael J.; Rhodes, Steven D.; Jiang, Li; Li, Xiaohong; Yuan, Jin; Yang, Xianlin; Zhang, Shaobo; Vakili, Saeed T.; Territo, Paul; Hutchins, Gary; Yang, Feng-Chun; Ingram, David A.; Clapp, D. Wade; Chen, Shi

    2016-01-01

    Purpose Plexiform neurofibromas (pNF) are pathognomonic nerve and soft tissue tumors of neurofibromatosis type I (NF1), which are highly resistant to conventional chemotherapy and associated with significant morbidity/mortality. Disruption of aberrant SCF/c-Kit signaling emanating from the pNF microenvironment induced the first ever objective therapeutic responses in a recent phase 2 trial. Sunitinib malate is a potent, highly selective RTK inhibitor with activity against c-Kit, PDGFR, and VEGFR, which have also been implicated in the pathogenesis of these lesions. Here, we evaluate the efficacy of sunitinib malate in a preclinical Krox20;Nf1flox/− pNF murine model. Experimental Design Proliferation, β-hexosaminidase release (degranulation), and Erk1/2 phosphorylation were assessed in sunitinib treated Nf1+/− mast cells and fibroblasts, respectively. Krox20;Nf1flox/− mice with established pNF were treated sunitinib or PBS-vehicle control for a duration of 12 weeks. pNF metabolic activity was monitored by serial [18F]DG-PET/CT imaging. Results Sunitinib suppressed multiple in vitro gain-in-functions of Nf1+/− mast cells and fibroblasts and attenuated Erk1/2 phosphorylation. Sunitinib treated Krox20;Nf1flox/− mice exhibited significant reductions in pNF size, tumor number, and FDG uptake compared to control mice. Histopathology revealed reduced tumor cellularity and infiltrating mast cells, markedly diminished collagen deposition, and increased cellular apoptosis in sunitinib treated pNF. Conclusions Collectively, these results demonstrate the efficacy of sunitinib in reducing tumor burden in Krox20;Nf1flox/− mice. These preclinical findings demonstrate the utility of inhibiting multiple RTKs in pNF and provide insights into the design of future clinical trials. PMID:26375012

  12. Safety Assessment of Dialkyl Malates as Used in Cosmetics.

    PubMed

    Becker, Lillian C; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-01-01

    The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of 6 dialkyl malate compounds used in cosmetics. These ingredients function mostly as skin-conditioning agents-emollients. The Panel reviewed relevant animal and human data related to the ingredients along with a previous safety assessment of malic acid. The similar structure, properties, functions, and uses of these ingredients enabled grouping them and using the available toxicological data to assess the safety of the entire group. The Panel concluded that these dialkyl maleate compounds are safe in the present practices of use and concentration as given in this safety assessment.

  13. Long noncoding RNA MALAT1 associates with the malignant status and poor prognosis in glioma.

    PubMed

    Ma, Kang-xiao; Wang, Hong-jie; Li, Xiao-rong; Li, Tao; Su, Gang; Yang, Pan; Wu, Jian-wen

    2015-05-01

    The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a bona fide long noncoding RNA (lncRNA). LncRNA MALAT1 was discovered as a prognostic factor for lung cancer metastasis but also has been linked to several other human tumor entities. However, little is known about the role of lncRNA MALAT1 in glioma patients. The aim of this study was to identify the role of lncRNA MALAT1 in the pathogenesis of glioma; we analyzed the relationship of lncRNA MALAT1 expression with clinicopathological characteristics in glioma patients. In our results, lncRNA MALAT1 expression was increased in glioma tissues compared with paired adjacent brain normal tissues (P < 0.001). Furthermore, lncRNA MALAT1 was associated significantly with WHO grade (I-II vs. III-IV; P = 0.007) and tumor size (< 3 cm vs. T ≥ 3 cm; P = 0.008). However, lncRNA MALAT1 expression was not associated significantly with age (<45 vs. ≥ 45, P = 0.343), gender (female vs. male, P = 0.196), family history of cancer (yes vs. no, P = 0.665), and tumor location (supratentorial vs. infratentorial, P = 0.170). Moreover, the level of lncRNA MALAT1 expression was markedly correlated with the glioma patients' overall survival (P < 0.001). Multivariate analysis suggested that increased lncRNA MALAT1 expression was a poor independent prognostic predictor for glioma patients (P = 0.002). In conclusion, lncRNA MALAT1 plays an important role on glioma progression and prognosis and may serve as a convictive prognostic biomarker for glioma patients.

  14. The action of exogenous abscisic acid on malate-synthase synthesis in germinating castor-bean seeds.

    PubMed

    Dommes, J; Northcote, D H

    1985-12-01

    The presence of 30 μM abscisic acid inhibited development of malate-synthase activity in the endosperm of germinating castor-bean seeds. Malate synthase was purified from castor-bean endosperms and an antibody to it was prepared from rabbit serum. This antibody was used to measure the amounts of malate-synthase mRNA using an in-vitro translation system. The effect of abscisic acid appeared to be greater on malate-synthase mRNA than on the bulk of mRNA, indicating some specificity of abscisic-acid action. The extent of the inhibition of malate-synthase activity and of malate-synthase mRNA accumulation were similar. This indicates that abscisic acid inhibits malate-synthase activity by lowering levels of translatable malate-synthase mRNA rather than by affecting the translation rate of this mRNA.

  15. The role of MALAT1 correlates with HPV in cervical cancer.

    PubMed

    Jiang, Yan; Li, Yuehui; Fang, Shujuan; Jiang, Binyuan; Qin, Changfei; Xie, Pingli; Zhou, Guohua; Li, Guancheng

    2014-06-01

    Cervical cancer, the second most common type of cancer in women worldwide, is responsible for >275,100 mortalities each year and is associated with high-risk human papilloma virus (HR-HPV). HPVs have two important oncogenes, E6 and E7, which have crucial roles in malignant transformation in cervical cancer. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA originally identified in non-small cell lung cancer. Previous studies have revealed that MALAT1 is expressed in numerous tissue types, and is significant in maintaining the normal function of the body. However, it also appeared to be notably upregulated in numerous carcinoma types compared with adjacent non-cancerous tissues. In the present study, it was identified that MALAT1 expression was upregulated in cervical cancer cell lines compared with normal cervical squamous cell samples. Further study into the effect of MALAT1 on cellular phenotype revealed that MALAT1 was able to promote cell migration and proliferation. Of note, it was revealed that the expression of MALAT1 was decreased with the knockdown of HPV16 E6/E7 in CaSki cells. Furthermore, the investigations in clinical samples also revealed that MALAT1 was expressed in HPV-positive cervical squamous cells, but not in HPV-negative normal cervical squamous cells. These results indicate that HPV correlates with MALAT1 deregulation in cervical cancer.

  16. Natural antisense RNA promotes 3′ end processing and maturation of MALAT1 lncRNA

    PubMed Central

    Zong, Xinying; Nakagawa, Shinichi; Freier, Susan M.; Fei, Jingyi; Ha, Taekjip; Prasanth, Supriya G.; Prasanth, Kannanganattu V.

    2016-01-01

    The RNase P-mediated endonucleolytic cleavage plays a crucial role in the 3′ end processing and cellular accumulation of MALAT1, a nuclear-retained long noncoding RNA that promotes malignancy. The regulation of this cleavage event is largely undetermined. Here we characterize a broadly expressed natural antisense transcript at the MALAT1 locus, designated as TALAM1, that positively regulates MALAT1 levels by promoting the 3′ end cleavage and maturation of MALAT1 RNA. TALAM1 RNA preferentially localizes at the site of transcription, and also interacts with MALAT1 RNA. Depletion of TALAM1 leads to defects in the 3′ end cleavage reaction and compromises cellular accumulation of MALAT1. Conversely, overexpression of TALAM1 facilitates the cleavage reaction in trans. Interestingly, TALAM1 is also positively regulated by MALAT1 at the level of both transcription and RNA stability. Together, our data demonstrate a novel feed-forward positive regulatory loop that is established to maintain the high cellular levels of MALAT1, and also unravel the existence of sense-antisense mediated regulatory mechanism for cellular lncRNAs that display RNase P-mediated 3′ end processing. PMID:26826711

  17. MALAT1 -- a paradigm for long noncoding RNA function in cancer.

    PubMed

    Gutschner, Tony; Hämmerle, Monika; Diederichs, Sven

    2013-07-01

    The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a bona fide long noncoding RNA (lncRNA). MALAT1, also known as nuclear-enriched transcript 2 (NEAT2), was discovered as a prognostic marker for lung cancer metastasis but also has been linked to several other human tumor entities. Recent work established a critical regulatory function of this lncRNA in lung cancer metastasis and cell migration. Moreover, MALAT1 is an interesting target for antimetastatic therapy in non-small cell lung carcinoma. Two alternative modes of action have been proposed for MALAT1: regulation of gene expression or alternative splicing. Although the exact mechanism of action in different physiological and pathological conditions still needs to be elucidated, MALAT1 acts as a regulator of gene expression. Although MALAT1 is highly evolutionary conserved in mammals and plays an important role in cancer and metastasis, MALAT1 is not essential for development in a knockout mouse model under normal physiological conditions. Hence, one central question for the future is finding the right stressor and the pathological or environmental condition which requires MALAT1 expression in vivo and entailing its strong evolutionary conservation. Here, we summarize the current knowledge about this important lncRNA. We introduce its discovery, biogenesis, and regulation and describe its known functions, mechanisms of action, and interaction partners.

  18. MALAT1 promotes colorectal cancer cell proliferation/migration/invasion via PRKA kinase anchor protein 9.

    PubMed

    Yang, Min-Hui; Hu, Zhi-Yan; Xu, Chuan; Xie, Lin-Ying; Wang, Xiao-Yan; Chen, Shi-You; Li, Zu-Guo

    2015-01-01

    Our previous studies have shown that the 3' end of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) is involved in colorectal cancer (CRC) cell proliferation and migration/invasion in vitro. The role and mechanism of MALAT1 in CRC metastasis in vivo, however, remain largely unknown. In the present study, we found that MALAT1 was up-regulated in human primary CRC tissues with lymph node metastasis. Overexpression of MALAT1 via RNA activation promoted CRC cell proliferation, invasion and migration in vitro, and stimulated tumor growth and metastasis in mice in vivo. Conversely, knockdown of MALAT1 inhibited CRC tumor growth and metastasis. MALAT1 regulated at least 243 genes in CRC cells in a genome-wide expression profiling. Among these genes, PRKA kinase anchor protein 9 (AKAP-9) was significantly up-regulated at both mRNA and protein levels. AKAP-9 was highly expressed in CRC cells with metastatic potential and human primary CRC tissues with lymph node metastasis, but not in normal cells or tissues. Importantly, knockdown of AKAP-9 blocked MALAT1-mediated CRC cell proliferation, migration and invasion. These data indicate that MALAT1 may promote CRC tumor development via its target protein AKAP-9.

  19. Function, kinetic properties, crystallization, and regulation of microbial malate dehydrogenase*

    PubMed Central

    Takahashi-Íñiguez, Tóshiko; Aburto-Rodríguez, Nelly; Vilchis-González, Ana Laura; Flores, María Elena

    2016-01-01

    Malate dehydrogenase (MDH) is an enzyme widely distributed among living organisms and is a key protein in the central oxidative pathway. It catalyzes the interconversion between malate and oxaloacetate using NAD+ or NADP+ as a cofactor. Surprisingly, this enzyme has been extensively studied in eukaryotes but there are few reports about this enzyme in prokaryotes. It is necessary to review the relevant information to gain a better understanding of the function of this enzyme. Our review of the data generated from studies in bacteria shows much diversity in their molecular properties, including weight, oligomeric states, cofactor and substrate binding affinities, as well as differences in the direction of the enzymatic reaction. Furthermore, due to the importance of its function, the transcription and activity of this enzyme are rigorously regulated. Crystal structures of MDH from different bacterial sources led to the identification of the regions involved in substrate and cofactor binding and the residues important for the dimer-dimer interface. This structural information allows one to make direct modifications to improve the enzyme catalysis by increasing its activity, cofactor binding capacity, substrate specificity, and thermostability. A comparative analysis of the phylogenetic reconstruction of MDH reveals interesting facts about its evolutionary history, dividing this superfamily of proteins into two principle clades and establishing relationships between MDHs from different cellular compartments from archaea, bacteria, and eukaryotes.

  20. Putative role of the malate valve enzyme NADP-malate dehydrogenase in H2O2 signalling in Arabidopsis.

    PubMed

    Heyno, Eiri; Innocenti, Gilles; Lemaire, Stéphane D; Issakidis-Bourguet, Emmanuelle; Krieger-Liszkay, Anja

    2014-04-19

    In photosynthetic organisms, sudden changes in light intensity perturb the photosynthetic electron flow and lead to an increased production of reactive oxygen species. At the same time, thioredoxins can sense the redox state of the chloroplast. According to our hypothesis, thioredoxins and related thiol reactive molecules downregulate the activity of H2O2-detoxifying enzymes, and thereby allow a transient oxidative burst that triggers the expression of H2O2 responsive genes. It has been shown recently that upon light stress, catalase activity was reversibly inhibited in Chlamydomonas reinhardtii in correlation with a transient increase in the level of H2O2. Here, it is shown that Arabidopsis thaliana mutants lacking the NADP-malate dehydrogenase have lost the reversible inactivation of catalase activity and the increase in H2O2 levels when exposed to high light. The mutants were slightly affected in growth and accumulated higher levels of NADPH in the chloroplast than the wild-type. We propose that the malate valve plays an essential role in the regulation of catalase activity and the accumulation of a H2O2 signal by transmitting the redox state of the chloroplast to other cell compartments. PMID:24591715

  1. Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss.

    PubMed

    Arun, Gayatri; Diermeier, Sarah; Akerman, Martin; Chang, Kung-Chi; Wilkinson, J Erby; Hearn, Stephen; Kim, Youngsoo; MacLeod, A Robert; Krainer, Adrian R; Norton, Larry; Brogi, Edi; Egeblad, Mikala; Spector, David L

    2016-01-01

    Genome-wide analyses have identified thousands of long noncoding RNAs (lncRNAs). Malat1 (metastasis-associated lung adenocarcinoma transcript 1) is among the most abundant lncRNAs whose expression is altered in numerous cancers. Here we report that genetic loss or systemic knockdown of Malat1 using antisense oligonucleotides (ASOs) in the MMTV (mouse mammary tumor virus)-PyMT mouse mammary carcinoma model results in slower tumor growth accompanied by significant differentiation into cystic tumors and a reduction in metastasis. Furthermore, Malat1 loss results in a reduction of branching morphogenesis in MMTV-PyMT- and Her2/neu-amplified tumor organoids, increased cell adhesion, and loss of migration. At the molecular level, Malat1 knockdown results in alterations in gene expression and changes in splicing patterns of genes involved in differentiation and protumorigenic signaling pathways. Together, these data demonstrate for the first time a functional role of Malat1 in regulating critical processes in mammary cancer pathogenesis. Thus, Malat1 represents an exciting therapeutic target, and Malat1 ASOs represent a potential therapy for inhibiting breast cancer progression.

  2. Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss

    PubMed Central

    Arun, Gayatri; Diermeier, Sarah; Akerman, Martin; Chang, Kung-Chi; Wilkinson, J. Erby; Hearn, Stephen; Kim, Youngsoo; MacLeod, A. Robert; Krainer, Adrian R.; Norton, Larry; Brogi, Edi; Egeblad, Mikala; Spector, David L.

    2016-01-01

    Genome-wide analyses have identified thousands of long noncoding RNAs (lncRNAs). Malat1 (metastasis-associated lung adenocarcinoma transcript 1) is among the most abundant lncRNAs whose expression is altered in numerous cancers. Here we report that genetic loss or systemic knockdown of Malat1 using antisense oligonucleotides (ASOs) in the MMTV (mouse mammary tumor virus)-PyMT mouse mammary carcinoma model results in slower tumor growth accompanied by significant differentiation into cystic tumors and a reduction in metastasis. Furthermore, Malat1 loss results in a reduction of branching morphogenesis in MMTV-PyMT- and Her2/neu-amplified tumor organoids, increased cell adhesion, and loss of migration. At the molecular level, Malat1 knockdown results in alterations in gene expression and changes in splicing patterns of genes involved in differentiation and protumorigenic signaling pathways. Together, these data demonstrate for the first time a functional role of Malat1 in regulating critical processes in mammary cancer pathogenesis. Thus, Malat1 represents an exciting therapeutic target, and Malat1 ASOs represent a potential therapy for inhibiting breast cancer progression. PMID:26701265

  3. Long non-coding RNA MALAT1 regulates retinal neurodegeneration through CREB signaling.

    PubMed

    Yao, Jin; Wang, Xiao-Qun; Li, Yu-Jie; Shan, Kun; Yang, Hong; Wang, Yang-Ning-Zhi; Yao, Mu-Di; Liu, Chang; Li, Xiu-Miao; Shen, Yi; Liu, Jing-Yu; Cheng, Hong; Yuan, Jun; Zhang, Yang-Yang; Jiang, Qin; Yan, Biao

    2016-01-01

    The nervous and vascular systems, although functionally different, share many common regulators of function maintenance. Long non-coding RNAs (lncRNAs) are important players in many biological processes and human disorders. We previously identified a role of MALAT1 in microvascular dysfunction. However, its role in neurodegeneration is still unknown. Here, we used the eye as the model to investigate the role of MALAT1 in retinal neurodegeneration. We show that MALAT1 expression is significantly up-regulated in the retinas, Müller cells, and primary retinal ganglion cells (RGCs) upon stress. MALAT1 knockdown reduces reactive gliosis, Müller cell activation, and RGC survival in vivo and in vitro MALAT1-CREB binding maintains CREB phosphorylation by inhibiting PP2A-mediated dephosphorylation, which leads to continuous CREB signaling activation. Clinical and animal experimentation suggests that MALAT1 dysfunction is implicated in neurodegenerative processes and several human disorders. Collectively, this study reveals that MALAT1 might regulate the development of retinal neurodegeneration through CREB signaling. PMID:26964565

  4. Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss.

    PubMed

    Arun, Gayatri; Diermeier, Sarah; Akerman, Martin; Chang, Kung-Chi; Wilkinson, J Erby; Hearn, Stephen; Kim, Youngsoo; MacLeod, A Robert; Krainer, Adrian R; Norton, Larry; Brogi, Edi; Egeblad, Mikala; Spector, David L

    2016-01-01

    Genome-wide analyses have identified thousands of long noncoding RNAs (lncRNAs). Malat1 (metastasis-associated lung adenocarcinoma transcript 1) is among the most abundant lncRNAs whose expression is altered in numerous cancers. Here we report that genetic loss or systemic knockdown of Malat1 using antisense oligonucleotides (ASOs) in the MMTV (mouse mammary tumor virus)-PyMT mouse mammary carcinoma model results in slower tumor growth accompanied by significant differentiation into cystic tumors and a reduction in metastasis. Furthermore, Malat1 loss results in a reduction of branching morphogenesis in MMTV-PyMT- and Her2/neu-amplified tumor organoids, increased cell adhesion, and loss of migration. At the molecular level, Malat1 knockdown results in alterations in gene expression and changes in splicing patterns of genes involved in differentiation and protumorigenic signaling pathways. Together, these data demonstrate for the first time a functional role of Malat1 in regulating critical processes in mammary cancer pathogenesis. Thus, Malat1 represents an exciting therapeutic target, and Malat1 ASOs represent a potential therapy for inhibiting breast cancer progression. PMID:26701265

  5. Malate Oxidation and Cyanide-Insensitive Respiration in Avocado Mitochondria during the Climacteric Cycle.

    PubMed

    Moreau, F; Romani, R

    1982-11-01

    After preparation on self-generated Percoll gradients, avocado (Persea americana Mill, var. Fuerte and Hass) mitochondria retain a high proportion of cyanide-insensitive respiration, especially with alpha-ketoglutarate and malate as substrates. Whereas alpha-ketoglutarate oxidation remains unchanged, the rate of malate oxidation increases as ripening advances through the climacteric. An enhancement of mitochondrial malic enzyme activity, measured by the accumulation of pyruvate, closely parallels the increase of malate oxidation. The capacity for cyanide-insensitive respiration is also considerably enhanced while respiratory control decreases (from 3.3 to 1.7), leading to high state 4 rates.Both malate dehydrogenase and malic enzyme are functional in state 3, but malic enzyme appears to predominate before the addition of ADP and after its depletion. In the presence of cyanide, a membrane potential is generated when the alterntive pathway is operating. Cyanide-insensitive malate oxidation can be either coupled to the first phosphorylation site, sensitive to rotenone, or by-pass this site. In the absence of phosphate acceptor, malate oxidation is mainly carried out via malic enzyme and the alternative pathway. Experimental modification of the external mitochondrial environment in vitro (pH, NAD(+), glutamade) results in changes in malate dehydrogenase and malic enzyme activities, which also modify cyanide resistance. It appears that a functional connection exists between malic enzyme and the alternative pathway via a rotenone-insensitive NADH dehydrogenase and that this pathway is responsible, in part, for nonphosphorylating respiratory activity during the climacteric.

  6. Long Noncoding RNA MALAT1 Promotes Aggressive Pancreatic Cancer Proliferation and Metastasis via the Stimulation of Autophagy.

    PubMed

    Li, Le; Chen, Hua; Gao, Yue; Wang, Yong-Wei; Zhang, Guang-Quan; Pan, Shang-Ha; Ji, Liang; Kong, Rui; Wang, Gang; Jia, Yue-Hui; Bai, Xue-Wei; Sun, Bei

    2016-09-01

    Recently, pancreatic ductal adenocarcinoma (PDAC) has emerged as one of the most aggressive malignant tumors with the worst prognosis. Previous studies have demonstrated that long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is increased in pancreatic cancer and is identified as a diagnostic biomarker. Nonetheless, the molecular mechanism of elevated MALAT1 levels and tumor aggressiveness remains unknown. In this study, MALAT1 was found to be highly expressed in PDAC tissues, and elevated expression was associated with poorer prognoses. In addition, MALAT1 was positively linearly correlated with the expression of LC3B mRNA. Furthermore, several molecules involved in cellular autophagic flux were modulated following the downregulation of MALAT1, including LC3, P62, and LAMP-2. Mechanistically, we found that MALAT1 interacted with RNA binding protein HuR, and silencing of MALAT1 greatly enhanced the posttranscriptional regulation of TIA-1 and had further effects on inhibiting autophagy. MALAT1 was speculated to regulate tumorigenesis via HuR-TIA-1-mediated autophagic activation. Hence, we investigated the biological properties of MALAT1 in terms of tumor proliferation and metastasis by promoting autophagy in vitro In brief, these data demonstrate that MALAT1 could facilitate the advanced progression of tumors in vivo Our study highlights the new roles of MALAT1 on protumorigenic functioning and anticancer therapy via activating autophagy in pancreatic cancer. Mol Cancer Ther; 15(9); 2232-43. ©2016 AACR.

  7. The noncoding RNA MALAT1 is a critical regulator of the metastasis phenotype of lung cancer cells.

    PubMed

    Gutschner, Tony; Hämmerle, Monika; Eissmann, Moritz; Hsu, Jeff; Kim, Youngsoo; Hung, Gene; Revenko, Alexey; Arun, Gayatri; Stentrup, Marion; Gross, Matthias; Zörnig, Martin; MacLeod, A Robert; Spector, David L; Diederichs, Sven

    2013-02-01

    The long noncoding RNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), also known as MALAT-1 or NEAT2 (nuclear-enriched abundant transcript 2), is a highly conserved nuclear noncoding RNA (ncRNA) and a predictive marker for metastasis development in lung cancer. To uncover its functional importance, we developed a MALAT1 knockout model in human lung tumor cells by genomically integrating RNA destabilizing elements using zinc finger nucleases. The achieved 1,000-fold MALAT1 silencing provides a unique loss-of-function model. Proposed mechanisms of action include regulation of splicing or gene expression. In lung cancer, MALAT1 does not alter alternative splicing but actively regulates gene expression including a set of metastasis-associated genes. Consequently, MALAT1-deficient cells are impaired in migration and form fewer tumor nodules in a mouse xenograft. Antisense oligonucleotides (ASO) blocking MALAT1 prevent metastasis formation after tumor implantation. Thus, targeting MALAT1 with ASOs provides a potential therapeutic approach to prevent lung cancer metastasis with this ncRNA serving as both predictive marker and therapeutic target. Finally, regulating gene expression, but not alternative splicing, is the critical function of MALAT1 in lung cancer metastasis. In summary, 10 years after the discovery of the lncRNA MALAT1 as a biomarker for lung cancer metastasis, our loss-of-function model unravels the active function of MALAT1 as a regulator of gene expression governing hallmarks of lung cancer metastasis.

  8. Long noncoding RNA MALAT1 promotes hepatic steatosis and insulin resistance by increasing nuclear SREBP-1c protein stability

    PubMed Central

    Yan, Caifeng; Chen, Jinfeng; Chen, Nuoqi

    2016-01-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is implicated in liver cell proliferation. However, its role in hepatic steatosis and insulin resistance remain poorly understood. The aim of this study was to investigate the effects of MALAT1 on hepatic lipid accumulation and its potential targets. As expected, MALAT1 expression is increased in hepatocytes exposed to palmitate and livers of ob/ob mice. Knockdown of MALAT1 expression dramatically suppressed palmitate-induced lipid accumulation and the increase of nuclear SREBP-1c protein in HepG2 cells. In addition, RNA immunoprecipitation and RNA pull-down assay confirmed that MALAT1 interacted with SREBP-1c to stabilize nuclear SREBP-1c protein. Finally, injection of si-MALAT1 prevented hepatic lipid accumulation and insulin resistance in ob/ob mice. In conclusion, our observations suggest that MALAT1 promotes hepatic steatosis and insulin resistance by increasing nuclear SREBP-1c protein stability. PMID:26935028

  9. Long noncoding RNA MALAT1 promotes hepatic steatosis and insulin resistance by increasing nuclear SREBP-1c protein stability.

    PubMed

    Yan, Caifeng; Chen, Jinfeng; Chen, Nuoqi

    2016-03-03

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is implicated in liver cell proliferation. However, its role in hepatic steatosis and insulin resistance remain poorly understood. The aim of this study was to investigate the effects of MALAT1 on hepatic lipid accumulation and its potential targets. As expected, MALAT1 expression is increased in hepatocytes exposed to palmitate and livers of ob/ob mice. Knockdown of MALAT1 expression dramatically suppressed palmitate-induced lipid accumulation and the increase of nuclear SREBP-1c protein in HepG2 cells. In addition, RNA immunoprecipitation and RNA pull-down assay confirmed that MALAT1 interacted with SREBP-1c to stabilize nuclear SREBP-1c protein. Finally, injection of si-MALAT1 prevented hepatic lipid accumulation and insulin resistance in ob/ob mice. In conclusion, our observations suggest that MALAT1 promotes hepatic steatosis and insulin resistance by increasing nuclear SREBP-1c protein stability.

  10. Esterase and Malate Dehydrogenase Phenotypes in Portuguese Populations of Meloidogyne Species

    PubMed Central

    Pais, Célia S.; de O. Abrantes, Isabel M.

    1989-01-01

    Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populations from Portugal were analyzed by electrophoresis in 0.4-mm-thick polyacrylamide gels. Fourteen major bands of esterase activity were detected, corresponding to 10 distinct phenotypes, Meloidogyne javanica and M. hapla had distinct species-specific phenotypes. Two phenotypes occurred in M. arenaria. The most variability was found among M. incognita populations. Of the remaining two phenotypes, one was associated with M. hispanica and the other belonged to a new species. Three malate dehydrogenase phenotypes were discerned on the basis of particular combinations of the eight main bands of activity found. As previously found, esterases were more useful than malate dehydrogenases in identification of the major Meloidogyne species. The host plant had no effect on the nematode esterase or malate dehydrogenase phenotypes. PMID:19287618

  11. Effect of Malate-oligosaccharide Solution on Antioxidant Capacity of Endurance Athletes

    PubMed Central

    Qiang, Fu

    2015-01-01

    L-malate is an important intermediate on the process of metabolism; it plays an important role in generating mitochondria ATP both under aerobic and hypoxic condition. It is easy to be absorbed and come into mitochondrion through cell membrane and promote to produce energy in mitochondrion. The purpose of this investigation is to probe into the different influence malate ingestion on blood lactate and glucose kinetics during aerobic exercise athletes; at the same time, rats were used to study the effect of malate and oligosaccharide solution on the metabolism in muscle and liver. The supplement of malate-oligosaccharide solution may improve the level of antioxidants in vivo after exercise, and subsequently increase the total antioxidant capacity and decrease the level of lipid peroxidation. At the appropriate time sports drinks can add varying degrees of motion to extend time to fatigue enhance athletic ability, speed up the recovery process after exercise, reduce fatigue. PMID:26998183

  12. Novel insight into MALAT-1 in cancer: Therapeutic targets and clinical applications

    PubMed Central

    REN, DANYANG; LI, HUIYING; LI, RENQIU; SUN, JIANMING; GUO, PIN; HAN, HUIYUN; YANG, YUEHUANG; LI, JUN

    2016-01-01

    Long non-protein-coding RNAs (lncRNAs) are emerging as important gene expression regulators that are linked to various biological processes at the post-transcriptional and transcriptional levels. lncRNAs are known to be important in cell proliferation, cell differentiation, apoptosis and metastasis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), a novel lncRNA, is highly conserved amongst mammals. In addition, it has been considered to act as an oncogene, depending on the tumor system. An increasing number of studies have indicated that MALAT-1 may be detected in certain types of human tumors, including lung and bladder cancer and hepatocellular carcinoma. MALAT-1 silencing may be an effective therapeutic approach against tumors. The present study reviews the current knowledge on the functional role of MALAT-1 in the control of various cancers. PMID:26998053

  13. Effect of Malate-oligosaccharide Solution on Antioxidant Capacity of Endurance Athletes.

    PubMed

    Qiang, Fu

    2015-01-01

    L-malate is an important intermediate on the process of metabolism; it plays an important role in generating mitochondria ATP both under aerobic and hypoxic condition. It is easy to be absorbed and come into mitochondrion through cell membrane and promote to produce energy in mitochondrion. The purpose of this investigation is to probe into the different influence malate ingestion on blood lactate and glucose kinetics during aerobic exercise athletes; at the same time, rats were used to study the effect of malate and oligosaccharide solution on the metabolism in muscle and liver. The supplement of malate-oligosaccharide solution may improve the level of antioxidants in vivo after exercise, and subsequently increase the total antioxidant capacity and decrease the level of lipid peroxidation. At the appropriate time sports drinks can add varying degrees of motion to extend time to fatigue enhance athletic ability, speed up the recovery process after exercise, reduce fatigue. PMID:26998183

  14. β-Carboline alkaloids from Galianthe ramosa inhibit malate synthase from Paracoccidioides spp.

    PubMed

    de Freitas, Carla S; Kato, Lucilia; de Oliveira, Cecília M A; Queiroz, Luiz H K; Santana, Mábio J; Schuquel, Ivânia T; Delprete, Piero G; da Silva, Roosevelt A; Quintino, Guilherme O; da Silva Neto, Benedito R; Soares, Célia M A; Pereira, Maristela

    2014-12-01

    As part of our continuing chemical and biological analyses of Rubiaceae species from Cerrado, we isolated novel alkaloids 1 and 2, along with known compounds epicatechin, ursolic acid, and oleanolic acid, from Galianthe ramosa. Alkaloid 2 inhibited malate synthase from the pathogenic fungus Paracoccidioides spp. This enzyme is considered an important molecular target because it is not found in humans. Molecular docking simulations were used to describe the interactions between the alkaloids and malate synthase.

  15. Fine-Tuned Transcriptional Regulation of Malate Operons in Enterococcus faecalis

    PubMed Central

    Mortera, Pablo; Espariz, Martín; Suárez, Cristian; Repizo, Guillermo; Deutscher, Josef; Alarcón, Sergio; Blancato, Víctor

    2012-01-01

    In Enterococcus faecalis, the mae locus is constituted by two putative divergent operons, maePE and maeKR. The first operon encodes a putative H+/malate symporter (MaeP) and a malic enzyme (MaeE) previously shown to be essential for malate utilization in this bacterium. The maeKR operon encodes two putative proteins with significant similarity to two-component systems involved in sensing malate and activating its assimilation in bacteria. Our transcriptional and genetic assays showed that maePE and maeKR are induced in response to malate by the response regulator MaeR. In addition, we observed that both operons were partially repressed in the presence of glucose. Accordingly, the cometabolism of this sugar and malate was detected. The binding of the complex formed by CcpA and its corepressor P-Ser-HPr to a cre site located in the mae region was demonstrated in vitro and explains the carbon catabolite repression (CCR) observed for the maePE operon. However, our results also provide evidence for a CcpA-independent CCR mechanism regulating the expression of both operons. Finally, a biomass increment of 40 or 75% was observed compared to the biomass of cells grown only on glucose or malate, respectively. Cells cometabolizing both carbon sources exhibit a higher rate of glucose consumption and a lower rate of malate utilization. The growth improvement achieved by E. faecalis during glucose-malate cometabolism might explain why this microorganism employs different regulatory systems to tightly control the assimilation of both carbon sources. PMID:22247139

  16. Protective effects of low-intensity pulsed ultrasound on aluminum-induced cerebral damage in Alzheimer's disease rat model.

    PubMed

    Lin, Wei-Ting; Chen, Ran-Chou; Lu, Wen-Wei; Liu, Shing-Hwa; Yang, Feng-Yi

    2015-04-15

    The protein expressions of neurotrophic factors can be enhanced by low-intensity pulsed ultrasound (LIPUS) stimulation in the brain. The purpose of this study was to demonstrate the protective effect of LIPUS stimulation against aluminum-induced cerebral damage in Alzheimer's disease rat model. LIPUS was administered 7 days before each aluminum chloride (AlCl3) administration, and concomitantly given with AlCl3 daily for a period of 6 weeks. Neurotrophic factors in hippocampus were measured by western blot analysis. Behavioral changes in the Morris water maze and elevated plus maze were examined in rats after administration of AlCl3. Various biochemical analyses were performed to evaluate the extent of brain damages. LIPUS is capable of prompting levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and vascular endothelial growth factor (VEGF) in rat brain. AlCl3 administration resulted in a significant increase in the aluminum concentration, acetylcholinesterase activity and beta-amyloid (Aβ) deposition in AlCl3 treated rats. LIPUS stimulation significantly attenuated aluminum concentration, acetylcholinesterase activity, Aβ deposition and karyopyknosis in AlCl3 treated rats. Furthermore, LIPUS significantly improved memory retention in AlCl3-induced memory impairment. These experimental results indicate that LIPUS has neuroprotective effects against AlCl3-induced cerebral damages and cognitive dysfunction.

  17. Protective effects of low-intensity pulsed ultrasound on aluminum-induced cerebral damage in Alzheimer's disease rat model

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Ting; Chen, Ran-Chou; Lu, Wen-Wei; Liu, Shing-Hwa; Yang, Feng-Yi

    2015-04-01

    The protein expressions of neurotrophic factors can be enhanced by low-intensity pulsed ultrasound (LIPUS) stimulation in the brain. The purpose of this study was to demonstrate the protective effect of LIPUS stimulation against aluminum-induced cerebral damage in Alzheimer's disease rat model. LIPUS was administered 7 days before each aluminum chloride (AlCl3) administration, and concomitantly given with AlCl3 daily for a period of 6 weeks. Neurotrophic factors in hippocampus were measured by western blot analysis. Behavioral changes in the Morris water maze and elevated plus maze were examined in rats after administration of AlCl3. Various biochemical analyses were performed to evaluate the extent of brain damages. LIPUS is capable of prompting levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and vascular endothelial growth factor (VEGF) in rat brain. AlCl3 administration resulted in a significant increase in the aluminum concentration, acetylcholinesterase activity and beta-amyloid (Aβ) deposition in AlCl3 treated rats. LIPUS stimulation significantly attenuated aluminum concentration, acetylcholinesterase activity, Aβ deposition and karyopyknosis in AlCl3 treated rats. Furthermore, LIPUS significantly improved memory retention in AlCl3-induced memory impairment. These experimental results indicate that LIPUS has neuroprotective effects against AlCl3-induced cerebral damages and cognitive dysfunction.

  18. The Long Noncoding RNA MALAT-1 Is Highly Expressed in Ovarian Cancer and Induces Cell Growth and Migration

    PubMed Central

    Zhou, Yanqing; Xu, Xiaying; Lv, Huabing; Wen, Qirong; Li, Juan; Tan, Linyu; Li, Jianqi; Sheng, Xiujie

    2016-01-01

    Background Metastasis associated in lung adenocarcinoma transcript-1 (MALAT-1) is overexpressed during cancer progression and promotes cell migration and invasion in many solid tumors. However, its role in ovarian cancer remains poorly understood. Methods Expressions of MALAT-1 were detected in 37 normal ovarian tissues and 45 ovarian cancer tissues by reverse transcription polymerase chain reaction (RT-PCR). Cell proliferation was observed by CCK-8 assay; Flow cytometry was used to measure cell cycle and apoptosis; Cell migration was detected by transwell migration and invasion assay. In order to evaluate the function of MALAT-1, shRNA combined with DNA microarray and Functional enrichment analysis were performed to determine the transcriptional effects of MALAT-1 silencing in OVCAR3 cells. RNA and protein expression were measured by qRT-PCR and Western blotting, respectively. Results We found that upregulation of MALAT-1 mRNA in ovarian cancer tissues and enhanced MALAT-1 expression was associated with FIGO stage. Knockdown of MALAT-1 expression in OVCAR3 cells inhibited cell proliferation, migration, and invasion, leading to G0/G1 cell cycle arrest and apoptosis. Overexpressed MALAT-1 expression in SKOV3 cells promoted cell proliferation, migration and invasion. Downregulation of MALAT-1 resulted in significant change of gene expression (at least 2-fold) in 449 genes, which regulate proliferation, cell cycle, and adhesion. As a consequence of MALAT-1 knockdown, MMP13 protein expression decreased, while the expression of MMP19 and ADAMTS1 was increased. Conclusions The present study found that MALAT-1 is highly expressed in ovarian tumors. MALAT-1 promotes the growth and migration of ovarian cancer cells, suggesting that MALAT-1 may be an important contributor to ovarian cancer development. PMID:27227769

  19. MALAT1 promotes the proliferation and metastasis of osteosarcoma cells by activating the PI3K/Akt pathway.

    PubMed

    Dong, Yongqiang; Liang, Guojun; Yuan, Bo; Yang, Chaoqun; Gao, Rui; Zhou, Xuhui

    2015-03-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), one of the first found cancer-associated long noncoding RNAs (lncRNAs), involves in the development and progression of many types of tumors. An aberrant expression of MALAT1 was observed in hepatocellular carcinoma, cervical cancer, breast cancer, ovarian cancer, and colorectal cancer. However, the exact effects and molecular mechanisms of MALAT1 in osteosarcoma progression are still unknown up to now. Here, we investigated the role of MALAT1 in human osteosarcoma cell lines and clinical tumor samples in order to determine the function of this molecule. In our research, the MALAT1 messenger RNA (mRNA) was highly expressed in human osteosarcoma tissues, and its expression level was closely correlated with pulmonary metastasis. Then, we employed lentivirus-mediated knockdown of MALAT1 in U-2 OS and SaO2 to determine the role of MALAT1 in osteosarcoma cell lines. Lentivirus-mediated MALAT1 small interfering RNA (siRNA) could efficiently downregulated the expression level of MALAT1 in osteosarcoma cell lines. Knockdown of MALAT1 inhibited the proliferation and invasion of human osteosarcoma cell and suppressed its metastasis in vitro and vivo. At the same time, the proliferating cell nuclear antigen (PCNA), matrix metallopeptidase 9 (MMP-9), phosphorylated PI3Kp85α, and Akt expressions were significantly inhibited in MALAT1-deleted cells. These findings indicated that MALAT1 might suppress the tumor growth and metastasis via PI3K/AKT signaling pathway. Taken together, our data indicated that MALAT1 might be an oncogenic lncRNA that promoted proliferation and metastasis of osteosarcoma and could be regarded as a therapeutic target in human osteosarcoma.

  20. Role of malate transporter in lipid accumulation of oleaginous fungus Mucor circinelloides.

    PubMed

    Zhao, Lina; Cánovas-Márquez, José T; Tang, Xin; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

    2016-02-01

    Fatty acid biosynthesis in oleaginous fungi requires the supply of reducing power, NADPH, and the precursor of fatty acids, acetyl-CoA, which is generated in the cytosol being produced by ATP: citrate lyase which requires citrate to be, transported from the mitochondrion by the citrate/malate/pyruvate transporter. This transporter, which is within the mitochondrial membrane, transports cytosolic malate into the mitochondrion in exchange for mitochondrial citrate moving into the cytosol (Fig. 1). The role of malate transporter in lipid accumulation in oleaginous fungi is not fully understood, however. Therefore, the expression level of the mt gene, coding for a malate transporter, was manipulated in the oleaginous fungus Mucor circinelloides to analyze its effect on lipid accumulation. The results showed that mt overexpression increased the lipid content for about 70 % (from 13 to 22 % dry cell weight, CDW), whereas the lipid content in mt knockout mutant decreased about 27 % (from 13 to 9.5 % CDW) compared with the control strain. Furthermore, the extracellular malate concentration was decreased in the mt overexpressing strain and increased in the mt knockout strain compared with the wild-type strain. This work suggests that the malate transporter plays an important role in regulating lipid accumulation in oleaginous fungus M. circinelloides.

  1. Prognostic value of long noncoding RNA MALAT1 in various carcinomas: evidence from nine studies.

    PubMed

    Xue, Yuan; Teng, Yan-Qing; Zhou, Jian-Dong; Rui, Yong-Jun

    2016-01-01

    RNA-sequencing technology is progressing day by day. Numerous researches have showed that long noncoding RNAs (lncRNAs) play oncogenic or tumor suppressor roles in tumor biological processes. To our knowledge, many studies have identified a lot of lncRNAs with aberrant expression in several types of cancers. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a newly discovered lncRNA, has been reported that is overexpressed in several types of cancers. But the clinical value of MALAT1 in cancers remains unclear. Therefore, in this present study, we aimed to investigate potential clinical application role of MALAT1 as a prognostic biomarker in malignant tumors. We performed a detailed search in PubMed, Embase, Medline, and Cochrane Library until July 2015. According to the inclusion and exclusion criteria, nine studies with a total of 941 patients were selected to explore the relationship between high expression of MALAT1 and overall survival in cancers. The result showed that overexpression of MALAT1 could predict poor overall survival (OS) in cancer patients, with pooled hazard ratio (HR) of 1.90 [95 % confidence interval (CI) 1.68-2.16, P < 0.0001]. In conclusion, the present meta-analysis demonstrated that high expression of MALAT1 might be served as a novel prognostic biomarker in different types of cancers.

  2. Long Noncoding RNA MALAT1: Insights into its Biogenesis and Implications in Human Disease.

    PubMed

    Wu, Yuting; Huang, Cheng; Meng, Xiaoming; Li, Jun

    2015-01-01

    Genome-wide studies have identified thousands of noncoding RNAs (ncRNAs) with no protein coding capacity. Among them, the long non-coding RNAs (lncRNAs), which are more than 200 nucleotides in length, recently are widely concerned for their crucial role in regulating biological processes and diseases. However, most lncRNAs are expressed at a very low level, and generally exhibit poor primary sequence conservation over evolution. Long non-coding RNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), also known as NEAT2 (nuclear-enriched abundant transcript 2), is outstanding among the lncRNA family due to its evolutionarily high conservation and abundant expression throughout diferent mammalian species. Meanwhile, MALAT1 was one of the first lncRNAs that was demonstrated to be associated with a disease, namely non-small cell lung cancer (NSCLC). Subsequently, MALAT1 was identified in multiple types of physiological processes, such as alternative splicing, nuclear organization, epigenetic modulating of gene expression, and so on. Moreover, a growing number of evidences indicated that MALAT1 was also closely related to various pathological processes, ranging from diabetes complications to cancers.In this review, we will make a summary on current understanding of MALAT1 in different physiological or pathophysiological processes and discuss the potential therapeutic applications based on MALAT1 detection and inhibition.

  3. Malate dehydrogenase: a useful phylogenetic marker for the genus Aeromonas.

    PubMed

    Farfán, Maribel; Miñana-Galbis, David; Garreta, Albert; Lorén, J Gaspar; Fusté, M Carmen

    2010-12-01

    The reconstruction of correct genealogies among biological entities, the estimation of the divergence time between organisms or the study of the different events that occur along evolutionary lineages are not always based on suitable genes. For reliable results, it is necessary to look at full-length sequences of genes under stabilizing selection (neutral or purifying) and behaving as good molecular clocks. In bacteria it has been proved that the malate dehydrogenase gene (mdh) can be used to determine the inter- and intraspecies divergence, and hence this gene constitutes a potential marker for phylogeny and bacterial population genetics. We have sequenced the full-length mdh gene in 36 type and reference strains of Aeromonas. The species grouping obtained in the phylogenetic tree derived from mdh sequences was in agreement with that currently accepted for the genus Aeromonas. The maximum likelihood models applied to our sequences indicated that the mdh gene is highly conserved among the Aeromonas species and the main evolutionary force acting on it is purifying selection. Only two sites under potential diversifying selection were identified (T 108 and S 193). In order to determine if these two residues could have an influence on the MDH structure, we mapped them in a three-dimensional model constructed from the sequence of A. hydrophila using the human mitochondrial MDH as a template. The presence of purifying selection together with the linear relationship between substitutions and gene divergence makes the mdh an excellent candidate gene for a phylogeny of Aeromonas and probably for other bacterial groups.

  4. Citrulline malate supplementation increases muscle efficiency in rat skeletal muscle.

    PubMed

    Giannesini, Benoît; Le Fur, Yann; Cozzone, Patrick J; Verleye, Marc; Le Guern, Marie-Emmanuelle; Bendahan, David

    2011-09-30

    Citrulline malate (CM; CAS 54940-97-5, Stimol®) is known to limit the deleterious effect of asthenic state on muscle function, but its effect under healthy condition remains poorly documented. The aim of this longitudinal double-blind study was to investigate the effect of oral ingestion of CM on muscle mechanical performance and bioenergetics in normal rat. Gastrocnemius muscle function was investigated strictly non-invasively using nuclear magnetic resonance techniques. A standardized rest-stimulation- (5.7 min of repeated isometric contractions electrically induced by transcutaneous stimulation at a frequency of 3.3 Hz) recovery-protocol was performed twice, i.e., before (t(0)-24 h) and after (t(0)+48 h) CM (3 g/kg/day) or vehicle treatment. CM supplementation did not affect PCr/ATP ratio, [PCr], [Pi], [ATP] and intracellular pH at rest. During the stimulation period, it lead to a 23% enhancement of specific force production that was associated to significant decrease in both PCr (28%) and oxidative (32%) costs of contraction, but had no effect on the time-courses of phosphorylated compounds and intracellular pH. Furthermore, both the rate of PCr resynthesis during the post-stimulation period (VPCr(rec)) and the oxidative ATP synthesis capacity (Q(max)) remained unaffected by CM treatment. These data demonstrate that CM supplementation under healthy condition has an ergogenic effect associated to an improvement of muscular contraction efficiency. PMID:21664351

  5. Streptococcus pyogenes malate degradation pathway links pH regulation and virulence.

    PubMed

    Paluscio, Elyse; Caparon, Michael G

    2015-03-01

    The ability of Streptococcus pyogenes to infect different niches within its human host most likely relies on its ability to utilize alternative carbon sources. In examining this question, we discovered that all sequenced S. pyogenes strains possess the genes for the malic enzyme (ME) pathway, which allows malate to be used as a supplemental carbon source for growth. ME is comprised of four genes in two adjacent operons, with the regulatory two-component MaeKR required for expression of genes encoding a malate permease (maeP) and malic enzyme (maeE). Analysis of transcription indicated that expression of maeP and maeE is induced by both malate and low pH, and induction in response to both cues is dependent on the MaeK sensor kinase. Furthermore, both maePE and maeKR are repressed by glucose, which occurs via a CcpA-independent mechanism. Additionally, malate utilization requires the PTS transporter EI enzyme (PtsI), as a PtsI(-) mutant fails to express the ME genes and is unable to utilize malate. Virulence of selected ME mutants was assessed in a murine model of soft tissue infection. MaeP(-), MaeK(-), and MaeR(-) mutants were attenuated for virulence, whereas a MaeE(-) mutant showed enhanced virulence compared to that of the wild type. Taken together, these data show that ME contributes to S. pyogenes' carbon source repertory, that malate utilization is a highly regulated process, and that a single regulator controls ME expression in response to diverse signals. Furthermore, malate uptake and utilization contribute to the adaptive pH response, and ME can influence the outcome of infection.

  6. Streptococcus pyogenes Malate Degradation Pathway Links pH Regulation and Virulence

    PubMed Central

    Paluscio, Elyse

    2015-01-01

    The ability of Streptococcus pyogenes to infect different niches within its human host most likely relies on its ability to utilize alternative carbon sources. In examining this question, we discovered that all sequenced S. pyogenes strains possess the genes for the malic enzyme (ME) pathway, which allows malate to be used as a supplemental carbon source for growth. ME is comprised of four genes in two adjacent operons, with the regulatory two-component MaeKR required for expression of genes encoding a malate permease (maeP) and malic enzyme (maeE). Analysis of transcription indicated that expression of maeP and maeE is induced by both malate and low pH, and induction in response to both cues is dependent on the MaeK sensor kinase. Furthermore, both maePE and maeKR are repressed by glucose, which occurs via a CcpA-independent mechanism. Additionally, malate utilization requires the PTS transporter EI enzyme (PtsI), as a PtsI– mutant fails to express the ME genes and is unable to utilize malate. Virulence of selected ME mutants was assessed in a murine model of soft tissue infection. MaeP–, MaeK–, and MaeR– mutants were attenuated for virulence, whereas a MaeE– mutant showed enhanced virulence compared to that of the wild type. Taken together, these data show that ME contributes to S. pyogenes' carbon source repertory, that malate utilization is a highly regulated process, and that a single regulator controls ME expression in response to diverse signals. Furthermore, malate uptake and utilization contribute to the adaptive pH response, and ME can influence the outcome of infection. PMID:25583521

  7. The Association between Abnormal Long Noncoding RNA MALAT-1 Expression and Cancer Lymph Node Metastasis: A Meta-Analysis

    PubMed Central

    Wang, Jun; Pan, Yongsheng; Wu, Jie; Zhang, Cheng; Huang, Yuan; Zhao, Ruizhe; Cheng, Gong; Liu, Jinliang; Shao, Pengfei; Hua, Lixin; Wang, Zengjun

    2016-01-01

    Previous studies have investigated that the expression levels of MALAT-1 were higher in cancerous tissues than matched histologically normal tissues. And, to some extent, overexpression of MALAT-1 was inclined to lymph node metastasis. This meta-analysis collected all relevant articles and explored the association between MALAT-1 expression levels and lymph node metastasis. We searched PubMed, EmBase, Web of Science, Cochrane Library, and OVID to address the level of MALAT-1 expression in cancer cases and noncancerous controls (accessed February 2015). And 8 studies comprising 696 multiple cancer patients were included to assess this association. The odds ratio (OR) and its corresponding 95% confidence interval (CI) were calculated to assess the strength of the association using Stata 12.0 version software. The results revealed there was a significant difference in the incidence of lymph node metastasis between high MALAT-1 expression group and low MALAT-1 expression group (OR = 1.94, 95% CI 1.15–3.28, P = 0.013 random-effects model). Subgroup analysis indicated that MALAT-1 high expression had an unfavorable impact on lymph node metastasis in Chinese patients (OR = 1.87, 95% CI 1.01–2.46). This study demonstrated that the incidence of lymph node metastasis in patients detected with high MALAT-1 expression was higher than that in patients with low MALAT-1 expression in China. PMID:26989678

  8. LncRNA MALAT1 exerts oncogenic functions in lung adenocarcinoma by targeting miR-204

    PubMed Central

    Li, Jipeng; Wang, Jianhua; Chen, Yin; Li, Shanfeng; Jin, Mingwei; Wang, Huaying; Chen, Zhe; Yu, Wanjun

    2016-01-01

    Accumulating evidence indicates that the lncRNAs play a critical role in cancer progression and metastasis. In this study, we found that MALAT1 upregulation was associated with larger tumor size and lymph-node metastasis, and also correlated with shorter overall survival of lung adenocarcinoma patients. Furthermore, MALAT1 promotes EMT and metastasis of lung adenocarcinoma cells in vitro and in vivo. In particular, MALAT1 upregulated the expression of miR-204 target gene SLUG through competitively ‘spongeing’ miR-204. In summary we unveil a branch of the MALAT1/miR-204/SLUG pathway that regulates the progression of lung adenocarcinoma. PMID:27294002

  9. Long Noncoding RNA MALAT1 Controls Cell Cycle Progression by Regulating the Expression of Oncogenic Transcription Factor B-MYB

    PubMed Central

    Tripathi, Vidisha; Shen, Zhen; Chakraborty, Arindam; Giri, Sumanprava; Freier, Susan M.; Wu, Xiaolin; Zhang, Yongqing; Gorospe, Myriam; Prasanth, Supriya G.; Lal, Ashish; Prasanth, Kannanganattu V.

    2013-01-01

    The long noncoding MALAT1 RNA is upregulated in cancer tissues and its elevated expression is associated with hyper-proliferation, but the underlying mechanism is poorly understood. We demonstrate that MALAT1 levels are regulated during normal cell cycle progression. Genome-wide transcriptome analyses in normal human diploid fibroblasts reveal that MALAT1 modulates the expression of cell cycle genes and is required for G1/S and mitotic progression. Depletion of MALAT1 leads to activation of p53 and its target genes. The cell cycle defects observed in MALAT1-depleted cells are sensitive to p53 levels, indicating that p53 is a major downstream mediator of MALAT1 activity. Furthermore, MALAT1-depleted cells display reduced expression of B-MYB (Mybl2), an oncogenic transcription factor involved in G2/M progression, due to altered binding of splicing factors on B-MYB pre-mRNA and aberrant alternative splicing. In human cells, MALAT1 promotes cellular proliferation by modulating the expression and/or pre-mRNA processing of cell cycle–regulated transcription factors. These findings provide mechanistic insights on the role of MALAT1 in regulating cellular proliferation. PMID:23555285

  10. Intermolecular interactions of the malate synthase of Paracoccidioides spp

    PubMed Central

    2013-01-01

    Background The fungus Paracoccidioides spp is the agent of paracoccidioidomycosis (PCM), a pulmonary mycosis acquired by the inhalation of fungal propagules. Paracoccidioides malate synthase (PbMLS) is important in the infectious process of Paracoccidioides spp because the transcript is up-regulated during the transition from mycelium to yeast and in yeast cells during phagocytosis by murine macrophages. In addition, PbMLS acts as an adhesin in Paracoccidioides spp. The evidence for the multifunctionality of PbMLS indicates that it could interact with other proteins from the fungus and host. The objective of this study was to identify and analyze proteins that possibly bind to PbMLS (PbMLS-interacting proteins) because protein interactions are intrinsic to cell processes, and it might be possible to infer the function of a protein through the identification of its ligands. Results The search for interactions was performed using an in vivo assay with a two-hybrid library constructed in S. cerevisiae; the transcripts were sequenced and identified. In addition, an in vitro assay using pull-down GST methodology with different protein extracts (yeast, mycelium, yeast-secreted proteins and macrophage) was performed, and the resulting interactions were identified by mass spectrometry (MS). Some of the protein interactions were confirmed by Far-Western blotting using specific antibodies, and the interaction of PbMLS with macrophages was validated by indirect immunofluorescence and confocal microscopy. In silico analysis using molecular modeling, dynamics and docking identified the amino acids that were involved in the interactions between PbMLS and PbMLS-interacting proteins. Finally, the interactions were visualized graphically using Osprey software. Conclusion These observations indicate that PbMLS interacts with proteins that are in different functional categories, such as cellular transport, protein biosynthesis, modification and degradation of proteins and signal

  11. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness.

    PubMed

    Pérez-Guisado, Joaquín; Jakeman, Philip M

    2010-05-01

    The purpose of the present study was to determine the effects of a single dose of citrulline malate (CM) on the performance of flat barbell bench presses as an anaerobic exercise and in terms of decreasing muscle soreness after exercise. Forty-one men performed 2 consecutive pectoral training session protocols (16 sets). The study was performed as a randomized, double-blind, 2-period crossover design. Eight grams of CM was used in 1 of the 2 training sessions, and a placebo was used in the other. The subjects' resistance was tested using the repetitions to fatigue test, at 80% of their predetermined 1 repetition maximum (RM), in the 8 sets of flat barbell bench presses during the pectoral training session (S1-4 and S1'-4'). The p-value was 0.05. The number of repetitions showed a significant increase from placebo treatment to CM treatment from the third set evaluated (p <0.0001). This increase was positively correlated with the number of sets, achieving 52.92% more repetitions and the 100% of response in the last set (S4'). A significant decrease of 40% in muscle soreness at 24 hours and 48 hours after the pectoral training session and a higher percentage response than 90% was achieved with CM supplementation. The only side effect reported was a feeling of stomach discomfort in 14.63% of the subjects. We conclude that the use of CM might be useful to increase athletic performance in high-intensity anaerobic exercises with short rest times and to relieve postexercise muscle soreness. Thus, athletes undergoing intensive preparation involving a high level of training or in competitive events might profit from CM. PMID:20386132

  12. Day-night variations in malate concentration, osmotic pressure, and hydrostatic pressure in Cereus validus

    SciTech Connect

    Luettge, U.; Nobel, P.S.

    1984-07-01

    Malate concentration and stem osmotic pressure concomitantly increase during nighttime CO/sub 2/ fixation and then decrease during the daytime in the obligate Crassulacean acid metabolism (CAM) plant, Cereus validus (Cactaceae). Changes in malate osmotic pressure calculated using the Van't Hoff relation match the changes in stem osmotic pressure, indicating that changes in malate level affected the water relations of the succulent stems. In contrast to stem osmotic pressure, stem water potential showed little day-night changes, suggesting that changes in cellular hydrostatic pressure occurred. This was corroborated by direct measurements of hydrostatic pressure using the Juelich pressure probe where a small oil-filled micropipette is inserted directly into chlorenchyma cells, which indicated a 4-fold increase in hydrostatic pressure from dusk to dawn. A transient increase of hydrostatic pressure at the beginning of the dark period was correlated with a short period of stomatal closing between afternoon and nighttime CO/sub 2/ fixation, suggesting that the rather complex hydrostatic pressure patterns could be explained by an interplay between the effects of transpiration and malate levels. A second CAM plant, Agave deserti, showed similar day-night changes in hydrostatic pressure in its succulent leaves. It is concluded that, in addition to the inverted stomatal rhythm, the oscillations of malate markedly affect osmotic pressures and hence water relations of CAM plants. 13 references, 4 figures.

  13. 1-methyl malate from Berberis integerrima fruits enhances the antibacterial activity of ampicillin against Staphylococcus aureus.

    PubMed

    Alimirzaee, P; Gohari, A R; Hajiaghaee, R; Mirzaee, S; Jamalifar, H; Monsef-Esfahani, H R; Amin, Gh; Saeidnia, S; Shahverdi, A R

    2009-06-01

    The enhancement of the antibacterial activity of ampicillin by different extracts of Berberis integerrima fruits was evaluated against Staphylococcus aureus. Disk diffusion and agar dilution methods were used to determine the antibacterial activity of ampicillin in the absence and presence of different plant extracts or various fractions eluted by column chromatography. A clinical isolate of S. aureus was used as a test strain. The active component of B. integerrima fruits involved in the enhancement of ampicillin activity was purified and identified as 1-methyl malate using different spectroscopic methods. Both the ethanol extract of B. integerrima fruits and 1-methyl malate enhanced the antibacterial activity of ampicillin. The total extract as well as 1-methyl malate increased the antibacterial activity of ampicillin against the test strain. The potency of ampicillin against the test strain was increased 64-fold when tested with a sub-toxic concentration of total extract of B. integerrima fruits. Also, 1-methyl malate increased the bactericidal activity of ampicillin. In the presence of 2 mg/mL of 1-methyl malate the MIC of ampicillin for S. aureus decreased from 128 to 1 microg/mL (128-fold).

  14. The efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies.

    PubMed

    Goldust, Mohamad; Rezaee, Elham

    2013-05-01

    Objective: There are different medications for the treatment of scabies but the treatment of choice is still controversial. This study aimed at comparing the efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies. Methods: In total, 340 patients with scabies were enrolled, and randomized into two groups: the first group received 1% ivermectin applied topically to the affected skin and the second group received topical malation 0.5% lotion and were told to apply this twice with 1 week interval. Treatment was evaluated at intervals of 2 and 4 weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated. Results: Two application of topical ivermectin provided a cure rate of 67.6% at the 2-week follow-up, which increased to 85.2% at the 4-week follow-up after repeating the treatment. Treatment with two applications of malation 0.5% lotion was effective in 44.1% of patients at the 2-week follow-up, which increased to 67.6% at the 4-week follow-up after this treatment was repeated. Conclusion:Two application of ivermectin was as effective as single applications of malation 0.5% lotion at the 2-week follow-up. After repeating the treatment, ivermectin was superior to malation 0.5% lotion at the 4-week follow up.

  15. Selective permeability of rat liver mitochondria to purified malate dehydrogenase isoenzymes in vitro.

    PubMed Central

    Passarella, S; Marra, E; Doonan, S; Quagliariello, E

    1980-01-01

    1. The mitochondrial malate dehydrogenase from rat liver has been purified to a state of homogeneity as judged by starch-gel electrophoresis and the cytoplasmic isoenzyme has been obtained in a partically purified state. 2. Inhibition of the isoenzymes by sulphite has been studied. 3. In mitochondria loaded with sulphite, the catalytic activity of the (partially inhibited) internal malate dehydrogenase has been measured by addition of oxaloacetate to the suspension medium and observation of the consequent decrease in fluorescence of NADH. 4. Addition of mitochondrial malate dehydrogenase to suspensions of mitochondria loaded with sulphite resulted in an increase in the level of intramitochondrial enzymic activity as measured by the above technique. Addition of the cytoplasmic isoenzyme did not result in such an increase. 5. These results show that mitochondria in suspension are permeable to the mitochondrial malate dehydrogenase but not to the cytoplasmic isoenzyme. 6. This conclusion has been confirmed by direct measurement of a decrease of enzyme activity in solution and an increase inside the mitochondria after incubation of organelles in solutions containing mitochondrial malate dehydrogenase. No such effect was observed with the cytoplasmic isoenzyme. 7. Some features of the permeation process have been studied. PMID:7236231

  16. Blue native polyacrylamide gel electrophoresis and the monitoring of malate- and oxaloacetate-producing enzymes.

    PubMed

    Singh, R; Chénier, D; Bériault, R; Mailloux, R; Hamel, R D; Appanna, V D

    2005-09-30

    We demonstrate a facile blue native polyacrylamide gel electrophoresis (BN-PAGE) technique to detect two malate-generating enzymes, namely fumarase (FUM), malate synthase (MS) and four oxaloacetate-forming enzymes, namely pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK), citrate lyase (CL) and aspartate aminotransferase (AST). Malate dehydrogenase (MDH) was utilized as a coupling enzyme to detect either malate or oxaloacetate in the presence of their respective substrates and cofactors. The latter four oxaloacetate-forming enzymes were identified by 2,6-dichloroindophenol (DCIP) and p-iodonitrotetrazolium (INT) while the former two malate-producing enzymes were visualized by INT and phenazine methosulfate (PMS) in the reaction mixtures, respectively. The band formed at the site of enzymatic activity was easily quantified, while Coomassie staining provided information on the protein concentration. Hence, the expression and the activity of these enzymes can be readily evaluated. A two-dimensional (2D) BN-PAGE or SDS-PAGE enabled the rapid purification of the enzyme of interest. This technique also provides a quick and inexpensive means of quantifying these enzymatic activities in normal and stressed biological systems.

  17. Long Noncoding RNA MALAT-1 Can Predict Poor Prognosis: A Meta-Analysis

    PubMed Central

    Tang, Ruixue; Jiang, Mengtong; Liang, Lu; Xiong, Dandan; Dang, Yiwu; Chen, Gang

    2016-01-01

    Background MALAT-1 is a highly conserved nuclear long non-coding RNA (lncRNA). The overexpression of MALAT-1 has been reported in several types of cancers. This meta-analysis was conducted to further investigate its potential role as a prognostic indicator in various cancers. Material/Methods The meta-analysis was performed by use of systematic search terms in 13 databases for qualified papers on prognosis in cancer from inception to June 30, 2015. The combined hazard ratios (HRs) with 95% confidence interval (95% CI) were computed to demonstrate the effect of MALAT-1 on prognosis of cancers. Results A total of 590 papers were initially identified, and 17 studies were finally included in this paper. Meta-analysis was accomplished with a total of 1626 patients. Combined HRs and 95% CI were calculated by fixed-effects or random-effects models. The quality assessment of included studies was performed by the Newcastle-Ottawa scale (NOS). High expression of MALAT-1 was found to be an indicator of poor prognosis in overall survival (OS) (HR=1.84, 95% CI: 1.27–2.67) and disease-free survival (DFS) (HR=2.37, 95% CI: 1.55–3.62). In subgroups, the associations between MALAT-1 and survival were also apparent, for instance, in country subgroup: China (HR=1.85, 95% CI: 1.14–2.99). Conclusions The overexpression of MALAT-1 may be a potential prognostic indicator for various human cancers. PMID:26821178

  18. Aluminum-activated citrate and malate transporters from the MATE and ALMT families function independently to confer Arabidopsis aluminum tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) activated root malate and citrate exudation play an important role in Al tolerance in many plant species. AtALMT1, an Al-activated malate transporter, is a major contributor to Arabidopsis Al tolerance. Here, we demonstrate that a second, unrelated gene, AtMATE, encodes an Arabidopsi...

  19. Long non-coding RNA MALAT-1 overexpression predicts tumor recurrence of hepatocellular carcinoma after liver transplantation.

    PubMed

    Lai, Ming-chun; Yang, Zhe; Zhou, Lin; Zhu, Qian-qian; Xie, Hai-yang; Zhang, Feng; Wu, Li-ming; Chen, Lei-ming; Zheng, Shu-sen

    2012-09-01

    Metastasis-associated lung adenocarcinoma transcript 1(MALAT1), a long non-coding RNA (lncRNA), is up-regulated in many solid tumors and associated with cancer metastasis and recurrence. However, its role in hepatocellular carcinoma (HCC) remains poorly understood. In the present study, we evaluated the expression of MALAT1 by quantitative real-time PCR in 9 liver cancer cell lines and 112 HCC cases including 60 cases who received liver transplantation (LT) with complete follow-up data. Moreover, small interfering RNA (siRNA) was used to inhibit MALAT1 expression to investigate its biological role in tumor progression. We found that MALAT1 was up-regulated in both cell lines and clinical tissue samples. Patients with high expression level of MALAT1 had a significantly increased risk of tumor recurrence after LT, particularly in patients who exceeded the Milan criteria. On multivariate analysis, MALAT1 was an independent prognostic factor for predicting HCC recurrence (hazard ratio, 3.280, P = 0.003).In addition, inhibition of MALAT1 in HepG2 cells could effectively reduce cell viability, motility, invasiveness, and increase the sensitivity to apoptosis. Our data suggest that lncRNA MALAT1 play an important role in tumor progression and could be a novel biomarker for predicting tumor recurrence after LT and serve as a promising therapeutic target.

  20. MALAT1 promotes the proliferation and metastasis of gallbladder cancer cells by activating the ERK/MAPK pathway.

    PubMed

    Wu, Xiang-Song; Wang, Xu-An; Wu, Wen-Guang; Hu, Yun-Ping; Li, Mao-Lan; Ding, Qian; Weng, Hao; Shu, Yi-Jun; Liu, Tian-Yu; Jiang, Lin; Cao, Yang; Bao, Run-Fa; Mu, Jia-Sheng; Tan, Zhu-Jun; Tao, Feng; Liu, Ying-Bin

    2014-06-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long non-coding RNA (lncRNA), is associated with metastasis and is an independent prognostic factor for lung cancer. Recent studies have demonstrated that MALAT1 plays an important role in other malignancies. However, little is known about the role of MALAT1 in gallbladder carcinoma (GBC), which is the most common cancer of the biliary tract and has an extremely poor prognosis. In this study, we focused on the expression, biological functions and mechanism of MALAT1 in GBC and found that MALAT1 was significantly upregulated in GBC tissues compared with corresponding non-cancerous tissues. Knockdown of MALAT1 in GBC cell lines using lentivirus-mediated RNA interference significantly inhibited the proliferation and metastasis of the GBC cells both in vitro and in vivo. Furthermore, ERK/MAPK pathway was found to be inactivated in the GBC cell lines after MALAT1 knockdown. These results indicated that MALAT1 might serve as an oncogenic lncRNA that promotes proliferation and metastasis of GBC and activates the ERK/MAPK pathway.

  1. Malat1 regulates serum response factor through miR-133 as a competing endogenous RNA in myogenesis.

    PubMed

    Han, Xiaorui; Yang, Feng; Cao, Huiqing; Liang, Zicai

    2015-07-01

    Metastasis-associated lung adenocarcinoma transcript 1 (Malat1) is an example of a functional long noncoding RNA involved in many biologic processes. However, the mechanisms for Malat1 in myogenesis are unclear. Serum response factor (SRF) is a pivotal transcription factor for muscle proliferation and differentiation and is reported to be a target gene for muscle-specific microRNA-133 (miR-133). In this study, we initially found that silencing Malat1 in the mouse myoblast C2C12 cell line inhibited myocyte differentiation and decreased Srf at both the RNA and protein levels. Srf silencing decreased Malat1 expression as well. Further study revealed that Malat1 contained an miR-133 functional target site, and the interplay between Malat1 and Srf was miR-133 dependent. We demonstrated that Malat1 modulates Srf through miR-133 as a competing endogenous RNA and established a novel connection among Malat1, miR-133, and Srf in myoblast differentiation.

  2. Leaf malate and succinate accumulation are out of phase throughout the development of the CAM plant Ananas comosus.

    PubMed

    Rainha, N; Medeiros, V P; Ferreira, C; Raposo, A; Leite, J P; Cruz, C; Pacheco, C A; Ponte, D; Silva, A B

    2016-03-01

    In plants with Crassulacean Acid Metabolism (CAM), organic acids, mainly malate are crucial intermediates for carbon fixation. In this research we studied the circadian oscillations of three organic anions (malate, citrate, and succinate) in Ananas comosus, assessing the effect of season and plant development stage. Seasonal and plant development dependencies were observed. The circadian oscillations of malate and citrate were typical of CAM pathways reported in the literature. Citrate content was quite stable (25-30 μmol g(-1) FW) along the day, with a seasonal effect. Succinate was shown to have both diurnal and seasonal oscillations and also a correlation with malate, since it accumulated during the afternoon when malate content was normally at a minimum, suggesting a possible mechanistic effect between both anions in CAM and/or respiratory metabolisms. PMID:26773544

  3. Leaf malate and succinate accumulation are out of phase throughout the development of the CAM plant Ananas comosus.

    PubMed

    Rainha, N; Medeiros, V P; Ferreira, C; Raposo, A; Leite, J P; Cruz, C; Pacheco, C A; Ponte, D; Silva, A B

    2016-03-01

    In plants with Crassulacean Acid Metabolism (CAM), organic acids, mainly malate are crucial intermediates for carbon fixation. In this research we studied the circadian oscillations of three organic anions (malate, citrate, and succinate) in Ananas comosus, assessing the effect of season and plant development stage. Seasonal and plant development dependencies were observed. The circadian oscillations of malate and citrate were typical of CAM pathways reported in the literature. Citrate content was quite stable (25-30 μmol g(-1) FW) along the day, with a seasonal effect. Succinate was shown to have both diurnal and seasonal oscillations and also a correlation with malate, since it accumulated during the afternoon when malate content was normally at a minimum, suggesting a possible mechanistic effect between both anions in CAM and/or respiratory metabolisms.

  4. L-malate enhances the gene expression of carried proteins and antioxidant enzymes in liver of aged rats.

    PubMed

    Zeng, X; Wu, J; Wu, Q; Zhang, J

    2015-01-01

    Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. To investigate the antioxidant mechanism of L-malate in the mitochondria, we analyzed the change in gene expression of two malate-aspartate shuttle (MAS)-related carried proteins (AGC, aspartate/glutamate carrier and OMC, oxoglutarate/malate carrier) in the inner mitochondrial membrane, and three antioxidant enzymes (CAT, SOD, and GSH-Px) in the mitochondria. The changes in gene expression of these proteins and enzymes were examined by real-time RT-PCR in the heart and liver of aged rats treated with L-malate. L-malate was orally administered in rats continuously for 30 days using a feeding atraumatic needle. We found that the gene expression of OMC and GSH-Px mRNA in the liver increased by 39 % and 38 %, respectively, in the 0.630 g/kg L-malate treatment group than that in the control group. The expression levels of SOD mRNA in the liver increased by 39 %, 56 %, and 78 % in the 0.105, 0.210, and 0.630 g/kg L-malate treatment groups, respectively. No difference were observed in the expression levels of AGC, OMC, CAT, SOD, and GSH-Px mRNAs in the heart of rats between the L-malate treatment and control groups. These results predicted that L-malate may increase the antioxidant capacity of mitochondria by enhancing the expression of mRNAs involved in the MAS and the antioxidant enzymes.

  5. Respiratory properties and malate metabolism in Percoll-purified mitochondria isolated from pineapple, Ananas comosus (L.) Merr. cv. smooth cayenne.

    PubMed

    Hong, Hoang Thi Kim; Nose, Akihiro; Agarie, Sakae

    2004-10-01

    An investigation was made of the respiratory properties and the role of the mitochondria isolated from one phosphoenolpyruvate carboxykinase (PCK)-CAM plant Ananas comosus (pineapple) in malate metabolism during CAM phase III. Pineapple mitochondria showed very high malate dehydrogenase (MDH), and low malic enzyme (ME) and glutamate-oxaloacetate transaminase (GOT) activities. The mitochondria readily oxidized succinate and NADH with high rates and coupling, while they only oxidized NADPH in the presence of Ca(2+). Pineapple mitochondria oxidized malate with low rates under most assay conditions, despite increasing malate concentrations, optimizing pH, providing cofactors such as coenzyme A, thiamine pyrophosphate, and NAD(+), and supplying individually external glutamate or GOT. However, providing glutamate and GOT simultaneously strongly increased the rates of malate oxidation. The OAA easily permeated the mitochondrial membranes to import into or export out of pineapple mitochondria during malate oxidation, but the mitochondria did not consume external Asp or alpha-KG. These results suggest that OAA played a significant role in the mitochondrial malate metabolism of pineapple, in which malate was mainly oxidized by active mMDH to produce OAA which could be exported outside the mitochondria via a malate-OAA shuttle. Cytosolic GOT then consumed OAA by transamination in the presence of glutamate, leading to a large increase in respiration rates. The malate-OAA shuttle might operate as a supporting system for decarboxylation in phase III of PCK-CAM pineapple. This shuttle system may be important in pineapple to provide a source of energy and substrate OAA for cytosolic PCK activity during the day when cytosolic OAA and ATP was limited for the overall decarboxylation process.

  6. Respiratory properties and malate metabolism in Percoll-purified mitochondria isolated from pineapple, Ananas comosus (L.) Merr. cv. smooth cayenne.

    PubMed

    Hong, Hoang Thi Kim; Nose, Akihiro; Agarie, Sakae

    2004-10-01

    An investigation was made of the respiratory properties and the role of the mitochondria isolated from one phosphoenolpyruvate carboxykinase (PCK)-CAM plant Ananas comosus (pineapple) in malate metabolism during CAM phase III. Pineapple mitochondria showed very high malate dehydrogenase (MDH), and low malic enzyme (ME) and glutamate-oxaloacetate transaminase (GOT) activities. The mitochondria readily oxidized succinate and NADH with high rates and coupling, while they only oxidized NADPH in the presence of Ca(2+). Pineapple mitochondria oxidized malate with low rates under most assay conditions, despite increasing malate concentrations, optimizing pH, providing cofactors such as coenzyme A, thiamine pyrophosphate, and NAD(+), and supplying individually external glutamate or GOT. However, providing glutamate and GOT simultaneously strongly increased the rates of malate oxidation. The OAA easily permeated the mitochondrial membranes to import into or export out of pineapple mitochondria during malate oxidation, but the mitochondria did not consume external Asp or alpha-KG. These results suggest that OAA played a significant role in the mitochondrial malate metabolism of pineapple, in which malate was mainly oxidized by active mMDH to produce OAA which could be exported outside the mitochondria via a malate-OAA shuttle. Cytosolic GOT then consumed OAA by transamination in the presence of glutamate, leading to a large increase in respiration rates. The malate-OAA shuttle might operate as a supporting system for decarboxylation in phase III of PCK-CAM pineapple. This shuttle system may be important in pineapple to provide a source of energy and substrate OAA for cytosolic PCK activity during the day when cytosolic OAA and ATP was limited for the overall decarboxylation process. PMID:15361538

  7. Augmentation of aluminum-induced oxidative stress in rat cerebrum by presence of pro-oxidant (graded doses of ethanol) exposure.

    PubMed

    Nayak, Prasunpriya; Sharma, Shiv Bhushan; Chowdary, Nadella Vijaya Subbaraya

    2010-11-01

    Both aluminum and ethanol are pro-oxidants and neurotoxic. Considering the possibilities of co-exposure and sharing mechanisms of producing neurotoxicity, the present study was planned to identify the level of aluminum-induced oxidative stress in altered pro-oxidant (ethanol exposure) status of cerebrum. Male rats were coexposed to aluminum and ethanol for 4 weeks. After the exposure period, cerebral levels of protein, reduced glutathione (GSH), lipid peroxidation (TBARS) were measured. Activities of catalase, superoxide dismutase (SOD), glutathione reductase (GR) and glutathione perioxidase (GPx) of cerebrum were estimated. In most of the cases significant correlations were observed between the alterations and graded ethanol doses, suggesting a dose-dependency in pushing the oxidant equilibrium toward pro-oxidants. Aluminum is found to influence significantly all the studied parameters of oxidative stress. Likewise, ethanol also influenced these parameters significantly, except GR, while the interaction between ethanol and aluminum could significantly influence only the GSH content and GR activity of cerebrum. Present study demonstrate that coexposure of aluminum with pro-oxidant might favor development of aluminum-induced oxidative stress in cerebrum. This observation might be helpful in understanding of mechanism of neurodegenerative disorders and ameliorate them.

  8. Evaluating the potential role of pomegranate peel in aluminum-induced oxidative stress and histopathological alterations in brain of female rats.

    PubMed

    Abdel Moneim, Ahmed E

    2012-12-01

    Studies have shown that pomegranate, Punica granatum Linn. (Lythraceae), has remarkable biological and medicinal properties. However, the effects of pomegranate peel methanolic extract (PPME) on the aluminum-induced oxidative stress and histopathological change have not been reported yet. To determine the effect of PPME (200 mg/kg bwt) on the aluminum chloride (AlCl₃; 34 mg/kg bwt)-induced neurotoxicity, aluminum accumulation in brain and oxidant/antioxidant status were determined. The change of brain structure was investigated with hematoxylin and eosin, and anti-apoptosis effects of PPME were analyzed by immunohistochemistry. The present study showed an indication of carcinogenicity in the AlCl₃-treated group representing an increase in tissue tumor markers such as tumor necrosis factor-α and angiogenin and inflammation by inducing an increase in prostaglandin E2 and prostaglandin F2α. PPME protected brain through decreasing the aluminum accumulation and stimulating antioxidant activities and anti-apoptotic proteins namely Bcl-2. Therefore, these results indicated that pomegranate peel methanolic extract could inhibit aluminum-induced oxidative stress and histopathological alternations in brain of female rats, and these effects may be related to anti-apoptotic and antioxidants activities. PMID:22945624

  9. Occurrence of the malate-aspartate shuttle in various tumor types.

    PubMed

    Greenhouse, W V; Lehninger, A L

    1976-04-01

    The activity of the malate-aspartate shuttle for the reoxidation of cytoplasmic reduced nicotinamide adenine dinucleotide (NADH) by mitochondria was assessed in six lines of rodent ascites tumor cells (two strains of Ehrlich ascites carcinoma, Krebs II carcinoma, Novikoff hepatoma, AS-30D hepatoma, and L1210 mouse leukemia). All the tumor cells examined showed mitochondrial reoxidation of cytoplasmic NADH, as evidenced by the accumulation of pyruvate when the cells were incubated aerobically with L-lactate. Reoxidation of cytoplasmic NADH thus generated was completely inhibited by the transaminase inhibitor aminooxyacetate. The involvement of the respiratory chain in the reoxidation of cytoplasmic NADH was demonstrated by the action of cyanide, rotenone, and antimycin A, which strongly inhibited the formation of pyruvate from added L-lactate. Compounds that inhibit the carrier-mediated entry of malate into mitochondria, such as butylmalonate, benzenetricarboxylate, and iodobenzylmalonate, also inhibited the accumulation of pyruvate from added L-lactate by the tumor cells. The maximal rate of the malate-aspartate shuttle was established by addtion of arsenite to inhibit the mitochondrial oxidation of the pyruvate formed from added lactate. The capacity of the various tumor lines for the reoxidation of cytoplasmic NADH via the malate-aspartate shuttle approaches 20% of the total respiratory rate of the cells and thus appears to be sufficient to account for the mitochondrial reoxidation of that fraction of glycolytic NADH not reoxidized by pyruvate and lactate dehydrognenase in the cytoplasm.

  10. CLYBL is a polymorphic human enzyme with malate synthase and β-methylmalate synthase activity

    PubMed Central

    Strittmatter, Laura; Li, Yang; Nakatsuka, Nathan J.; Calvo, Sarah E.; Grabarek, Zenon; Mootha, Vamsi K.

    2014-01-01

    CLYBL is a human mitochondrial enzyme of unknown function that is found in multiple eukaryotic taxa and conserved to bacteria. The protein is expressed in the mitochondria of all mammalian organs, with highest expression in brown fat and kidney. Approximately 5% of all humans harbor a premature stop polymorphism in CLYBL that has been associated with reduced levels of circulating vitamin B12. Using comparative genomics, we now show that CLYBL is strongly co-expressed with and co-evolved specifically with other components of the mitochondrial B12 pathway. We confirm that the premature stop polymorphism in CLYBL leads to a loss of protein expression. To elucidate the molecular function of CLYBL, we used comparative operon analysis, structural modeling and enzyme kinetics. We report that CLYBL encodes a malate/β-methylmalate synthase, converting glyoxylate and acetyl-CoA to malate, or glyoxylate and propionyl-CoA to β-methylmalate. Malate synthases are best known for their established role in the glyoxylate shunt of plants and lower organisms and are traditionally described as not occurring in humans. The broader role of a malate/β-methylmalate synthase in human physiology and its mechanistic link to vitamin B12 metabolism remain unknown. PMID:24334609

  11. The anomalous kinetics of coupled aspartate aminotransferase and malate dehydrogenase. Evidence for compartmentation of oxaloacetate.

    PubMed Central

    Bryce, C F; Williams, D C; John, R A; Fasella, P

    1976-01-01

    Cytoplasmic aspartate aminotransferase and malate dehydrogenase were purified from pig heart. Kinetic parameters were determined for the separate reaction catalysed by each enzyme and used to predict the course of the coupled reaction: (see article). Although a lag phase should have been easily seen, none was detected. The same coupled reaction was also carried out by using radioactive aspartate in the presence of unlabelled oxaloacetate. The reaction was quenched with HClO4 after 70 ms and the specific radioactivity of the malate produced in this system was found to be essentially the same as that of the original aspartate. These results show that oxaloacetate produced by the aspartate aminotransferase is converted into malate by malate dehydrogenase before it equilibrates with the pool of unlabelled oxaloacetate and are consistent with a proposal that the enzymes are associated in a complex. However, no physical evidence of the existence of a complex could be found. An alternative means of compartmentation of the intermediate as an unstable isomer is considered. Images Fig. 2. Fig. 3. PMID:942372

  12. Prognostic value of long noncoding RNA MALAT1 in digestive system malignancies

    PubMed Central

    Zhai, Hui; Li, Xiao-Mei; Maimaiti, Ailifeire; Chen, Qing-Jie; Liao, Wu; Lai, Hong-Mei; Liu, Fen; Yang, Yi-Ning

    2015-01-01

    Background: MALAT1, a newly discovered long noncoding RNA (lncRNA), has been reported to be highly expressed in many types of cancers. This meta-analysis summarizes its potential prognostic value in digestive system malignancies. Methods: A quantitative meta-analysis was performed through a systematic search in PubMed, Cochrane Library, Web of Science and Chinese National Knowledge Infrastructure (CNKI) for eligible papers on the prognostic impact of MALAT1 in digestive system malignancies from inception to Apr. 25, 2015. Pooled hazard ratios (HRs) with 95% confidence interval (95% CI) were calculated to summarize the effect. Results: Five studies were included in the study, with a total of 527 patients. A significant association was observed between MALAT1 abundance and poor overall survival (OS) of patients with digestive system malignancies, with pooled hazard ratio (HR) of 7.68 (95% confidence interval [CI]: 4.32-13.66, P<0.001). Meta sensitivity analysis suggested the reliability of our findings. No publication bias was observed. Conclusions: MALAT1 abundance may serve as a novel predictive factor for poor prognosis in patients with digestive system malignancies. PMID:26770406

  13. Malate synthase activity in cotton and other ungerminated oilseeds: a survey.

    PubMed

    Miernyk, J A; Trelease, R N; Choinski, J S

    1979-06-01

    Extracts from several species and varieties of ungerminated cotton seeds plus homogenates from 18 other oilseeds (representing 11 different families) were examined for malate synthase and isocitrate lyase activity. Malate synthase activities in the various cotton seeds ranged from 35 to 129% of the units per dry seed weight found in Deltapine 16 cotton. For other oilseeds, the range was from 0.3 to 58% of Deltapine 16 cotton. Castor bean (Ricinus communis L.) had the least activity per mg dry weight (12-fold lower than the next lowest species), while Pima cotton (Gossypium barbadense L.) had the highest level (8.53 units). On a per seed basis, these values were 15 and 747 nanomoles per minute.Malate synthase activity was measurable in all seed types examined, whereas isocitrate lyase could not be detected in any of the seeds. We suggest that synthesis of malate synthase during seed development is universal among oilseeds in the absence of glyoxylate-cycle-associated isocitrate lyase activity.

  14. Escherichia coli d-Malate Dehydrogenase, a Generalist Enzyme Active in the Leucine Biosynthesis Pathway*

    PubMed Central

    Vorobieva, Anastassia A.; Khan, Mohammad Shahneawz; Soumillion, Patrice

    2014-01-01

    The enzymes of the β-decarboxylating dehydrogenase superfamily catalyze the oxidative decarboxylation of d-malate-based substrates with various specificities. Here, we show that, in addition to its natural function affording bacterial growth on d-malate as a carbon source, the d-malate dehydrogenase of Escherichia coli (EcDmlA) naturally expressed from its chromosomal gene is capable of complementing leucine auxotrophy in a leuB− strain lacking the paralogous isopropylmalate dehydrogenase enzyme. To our knowledge, this is the first example of an enzyme that contributes with a physiologically relevant level of activity to two distinct pathways of the core metabolism while expressed from its chromosomal locus. EcDmlA features relatively high catalytic activity on at least three different substrates (l(+)-tartrate, d-malate, and 3-isopropylmalate). Because of these properties both in vivo and in vitro, EcDmlA may be defined as a generalist enzyme. Phylogenetic analysis highlights an ancient origin of DmlA, indicating that the enzyme has maintained its generalist character throughout evolution. We discuss the implication of these findings for protein evolution. PMID:25160617

  15. Homochiral Cu(II) and Ni(II) malates with tunable structural features

    NASA Astrophysics Data System (ADS)

    Zavakhina, Marina S.; Samsonenko, Denis G.; Virovets, Alexander V.; Dybtsev, Danil N.; Fedin, Vladimir P.

    2014-02-01

    Four new homochiral metal-organic frameworks (MOFs) based on S-malate anions and N-donor linkers of different length have been prepared under solvothermal conditions. [Cu(mal)(bpy)]·H2O (1), [Cu(mal)(bpe)]·2H2O (2), [Ni(mal)(bpy)]·1.3CH3OH (3) and [Ni(mal)(bpe)]·4H2O (4) (mal=S-malate, bpy=4,4‧-bipyridil, bpe=trans-1,2-bis(4-pyridyl)ethylene) were characterized by a number of analytical methods including powder X-ray diffraction, elemental, thermogravimetric analyses, IR spectroscopy. Compounds 1-3 were structurally characterized by X-ray crystallography. The absence of the chiral ligand racemization under synthetic conditions was unambiguously confirmed by polarimetry experiments. Compounds 1 and 2 contain metal-malate layered motives, connected by N-donor linkers and contribute to the family of isoreticular Cu(II) malates and tartrates [Cu(mal)L] and [Cu(tart)L], (tart=tartrate; L=ditopic rigid organic ligand). The Ni-based compounds 3 and 4 share 1D chiral {Ni(mal)} motives and possess novel type of the chiral framework, previously unknown for chiral carboxylates. The linear N-donor linkers connect these chiral chains, thus controlling the channel diameter and guest accessible volume of the homochiral structure, which exceeds 60 %.

  16. Homochiral Cu(II) and Ni(II) malates with tunable structural features

    SciTech Connect

    Zavakhina, Marina S.; Samsonenko, Denis G.; Virovets, Alexander V.; Dybtsev, Danil N.; Fedin, Vladimir P.

    2014-02-15

    Four new homochiral metal–organic frameworks (MOFs) based on S-malate anions and N-donor linkers of different length have been prepared under solvothermal conditions. [Cu(mal)(bpy)]·H{sub 2}O (1), [Cu(mal)(bpe)]·2H{sub 2}O (2), [Ni(mal)(bpy)]·1.3CH{sub 3}OH (3) and [Ni(mal)(bpe)]·4H{sub 2}O (4) (mal=S-malate, bpy=4,4′-bipyridil, bpe=trans-1,2-bis(4-pyridyl)ethylene) were characterized by a number of analytical methods including powder X-ray diffraction, elemental, thermogravimetric analyses, IR spectroscopy. Compounds 1–3 were structurally characterized by X-ray crystallography. The absence of the chiral ligand racemization under synthetic conditions was unambiguously confirmed by polarimetry experiments. Compounds 1 and 2 contain metal-malate layered motives, connected by N-donor linkers and contribute to the family of isoreticular Cu(II) malates and tartrates [Cu(mal)L] and [Cu(tart)L], (tart=tartrate; L=ditopic rigid organic ligand). The Ni-based compounds 3 and 4 share 1D chiral (Ni(mal)) motives and possess novel type of the chiral framework, previously unknown for chiral carboxylates. The linear N-donor linkers connect these chiral chains, thus controlling the channel diameter and guest accessible volume of the homochiral structure, which exceeds 60 %. - Graphical abstract: Four new homochiral metal–organic frameworks are built from Ni{sup 2+} or Cu{sup 2+} cations, S-malate anions and N-donor linkers of different length, which controls the size of pores and guest accessible volume of the homochiral structure. Display Omitted - Highlights: • Four new homohiral metal–organic frameworks based on Ni{sup 2+} and Cu{sup 2+}. • Cu(II)–malate layers and Ni(II)–malate chains are connected by N-donor linkers. • N-donor linkers of different length control the size of pores.

  17. How fumarase recycles after the malate --> fumarate reaction. Insights into the reaction mechanism.

    PubMed

    Rose, I A

    1998-12-22

    Recycling of yeast fumarase to permit repetition of its reaction chemistry requires two proton transfers and two conformational changes, in pathways that are different in detail but thematically similar in the two directions. In the malate --> fumarate direction, simple anions such as acetate accelerate the fumarate-off step producing E(H(f)), a fumarate-specific isoform that retains the C3R-proton of malate. Fumarate specificity is shown with S-2,3-dicarboxyaziridine, which is competitive vs fumarate and noncompetitive with malate as substrate. The steady-state level of E(H(f)), based on Kii (S-2,3-dicarboxyaziridine), is increased by D2O and decreased by imidazole acting as a general acid for conversion of E(H(f)) to E(H(f))H. E(H(f))H is fumarate-specific as shown by the inhibition pattern with ClO4-. The pKa of this step is approximately 7.25 based on the pH dependence of Kii (ClO4-). A conformational change occurs next as shown by high sensitivity of k(cat) but not k(cat)/Km, to the microviscosogen, glycerol, and change to a nonspecific isoform, E(H(mf))H, probably the same species formed in the fumarate --> malate direction from malate-specific intermediates by a different conformational change. Malate enters the cycle by reaction with E(H(mf))H and returns to E(m)H x malate after a second conformational change. When fumarate-off is slow, as in low anion medium, malate itself becomes an activator of malate --> fumarate. This effect occurs with changes in inhibition patterns suggestive of the bypass of the slow E(f) --> E(mf) conversion in favor of direct formation of E(mf) when free fumarate is formed. 3-Nitro-2-hydroxypropionate, a strong inhibitor of fumarase [Porter, D. J. T., and Bright, H. J. (1980) J. Biol. Chem. 255, 4772-4780] in its carbanion form, is competitive with both malate and fumarate. Therefore, 3-nitro-2-hydroxypropionic acid interacts with E(H(mf))H and not with E(m) or E(f) isoforms. Occurrence of two different conformational changes in

  18. L-citrulline-malate influence over branched chain amino acid utilization during exercise.

    PubMed

    Sureda, Antoni; Córdova, Alfredo; Ferrer, Miguel D; Pérez, Gerardo; Tur, Josep A; Pons, Antoni

    2010-09-01

    Exhaustive exercise induces disturbances in metabolic homeostasis which can result in amino acid catabolism and limited L-arginine availability. Oral L-citrulline supplementation raises plasma L-arginine concentration and augments NO-dependent signalling. Our aim was to evaluate the effects of diet supplementation with L-citrulline-malate prior to intense exercise on the metabolic handle of plasma amino acids and on the products of metabolism of arginine as creatinine, urea and nitrite and the possible effects on the hormonal levels. Seventeen voluntary male pre-professional cyclists were randomly assigned to one of two groups: control or supplemented (6 g L-citrulline-malate 2 h prior exercise) and participated in a 137-km cycling stage. Blood samples were taken in basal conditions, 15 min after the race and 3 h post race (recovery). Most essential amino acids significantly decreased their plasma concentration as a result of exercise; however, most non-essential amino acids tended to significantly increase their concentration. Citrulline-malate ingestion significantly increased the plasma concentration of citrulline, arginine, ornithine, urea, creatinine and nitrite (p < 0.05) and significantly decreased the isoleucine concentration from basal measures to after exercise (p < 0.05). Insulin levels significantly increased after exercise in both groups (p < 0.05) returning to basal values at recovery. Growth hormone increased after exercise in both groups, although the increase was higher in the citrulline-malate supplemented group (p < 0.05). L-citrulline-malate supplementation can enhance the use of amino acids, especially the branched chain amino acids during exercise and also enhance the production of arginine-derived metabolites such as nitrite, creatinine, ornithine and urea. PMID:20499249

  19. Myostatin-induced inhibition of the long noncoding RNA Malat1 is associated with decreased myogenesis.

    PubMed

    Watts, Rani; Johnsen, Virginia L; Shearer, Jane; Hittel, Dustin S

    2013-05-15

    Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily of secreted proteins, is a potent negative regulator of myogenesis. Free myostatin induces the phosphorylation of the Smad family of transcription factors, which, in turn, regulates gene expression, via the canonical TGF-β signaling pathway. There is, however, emerging evidence that myostatin can regulate gene expression independent of Smad signaling. As such, we acquired global gene expression data from the gastrocnemius muscle of C57BL/6 mice following a 6-day treatment with recombinant myostatin compared with vehicle-treated animals. Of the many differentially expressed genes, the myostatin-associated decrease (-11.20-fold; P < 0.05) in the noncoding metastasis-associated lung adenocarcinoma transcript 1 (Malat1) was the most significant and the most intriguing because of numerous reports describing its novel role in regulating cell growth. We therefore sought to further characterize the role of Malat1 expression in skeletal muscle myogenesis. RT-PCR-based quantification of C2C12 and primary human skeletal muscle cells revealed a significant and persistent upregulation (4- to 7-fold; P < 0.05) of Malat1 mRNA during the differentiation of myoblasts into myotubes. Conversely, targeted knockdown of Malat1 using siRNA suppressed myoblast proliferation by arresting cell growth in the G(0)/G(1) phase. These results reveal Malat1 as novel downstream target of myostatin with a considerable ability to regulate myogenesis. The identification of new targets of myostatin will have important repercussions for regenerative biology through inhibition and/or reversal of muscle atrophy and wasting diseases.

  20. Loss of the abundant nuclear non-coding RNA MALAT1 is compatible with life and development

    PubMed Central

    Eißmann, Moritz; Gutschner, Tony; Hämmerle, Monika; Günther, Stefan; Caudron-Herger, Maïwen; Groß, Matthias; Schirmacher, Peter; Rippe, Karsten; Braun, Thomas; Diederichs, Sven; Zörnig, Martin

    2012-01-01

    The metastasis-associated lung adenocarcinoma transcript 1, MALAT1, is a long non-coding RNA (lncRNA) that has been discovered as a marker for lung cancer metastasis. It is highly abundant, its expression is strongly regulated in many tumor entities including lung adenocarcinoma and hepatocellular carcinoma as well as physiological processes, and it is associated with many RNA binding proteins and highly conserved throughout evolution. The nuclear transcript MALAT-1 has been functionally associated with gene regulation and alternative splicing and its regulation has been shown to impact proliferation, apoptosis, migration and invasion.   Here, we have developed a human and a mouse knockout system to study the loss-of-function phenotypes of this important ncRNA. In human tumor cells, MALAT1 expression was abrogated using Zinc Finger Nucleases. Unexpectedly, the quantitative loss of MALAT1 did neither affect proliferation nor cell cycle progression nor nuclear architecture in human lung or liver cancer cells. Moreover, genetic loss of Malat1 in a knockout mouse model did not give rise to any obvious phenotype or histological abnormalities in Malat1-null compared with wild-type animals. Thus, loss of the abundant nuclear long ncRNA MALAT1 is compatible with cell viability and normal development. PMID:22858678

  1. The long noncoding RNA MALAT1 promotes tumor-driven angiogenesis by up-regulating pro-angiogenic gene expression

    PubMed Central

    Tee, Andrew E.; Liu, Bing; Song, Renhua; Li, Jinyan; Pasquier, Eddy; Cheung, Belamy B.; Jiang, Cizhong; Marshall, Glenn M.; Haber, Michelle; Norris, Murray D.; Fletcher, Jamie I.; Dinger, Marcel E.; Liu, Tao

    2016-01-01

    Neuroblastoma is the most common solid tumor during early childhood. One of the key features of neuroblastoma is extensive tumor-driven angiogenesis due to hypoxia. However, the mechanism through which neuroblastoma cells drive angiogenesis is poorly understood. Here we show that the long noncoding RNA MALAT1 was upregulated in human neuroblastoma cell lines under hypoxic conditions. Conditioned media from neuroblastoma cells transfected with small interfering RNAs (siRNA) targeting MALAT1, compared with conditioned media from neuroblastoma cells transfected with control siRNAs, induced significantly less endothelial cell migration, invasion and vasculature formation. Microarray-based differential gene expression analysis showed that one of the genes most significantly down-regulated following MALAT1 suppression in human neuroblastoma cells under hypoxic conditions was fibroblast growth factor 2 (FGF2). RT-PCR and immunoblot analyses confirmed that MALAT1 suppression reduced FGF2 expression, and Enzyme-Linked Immunosorbent Assays revealed that transfection with MALAT1 siRNAs reduced FGF2 protein secretion from neuroblastoma cells. Importantly, addition of recombinant FGF2 protein to the cell culture media reversed the effects of MALAT1 siRNA on vasculature formation. Taken together, our data suggest that up-regulation of MALAT1 expression in human neuroblastoma cells under hypoxic conditions increases FGF2 expression and promotes vasculature formation, and therefore plays an important role in tumor-driven angiogenesis. PMID:26848616

  2. Development and prospective multicenter evaluation of the long noncoding RNA MALAT-1 as a diagnostic urinary biomarker for prostate cancer.

    PubMed

    Wang, Fubo; Ren, Shancheng; Chen, Rui; Lu, Ji; Shi, Xiaolei; Zhu, Yasheng; Zhang, Wei; Jing, Taile; Zhang, Chao; Shen, Jian; Xu, Chuanliang; Wang, Huiqing; Wang, Haifeng; Wang, Yang; Liu, Bin; Li, Yaoming; Fang, Ziyu; Guo, Fei; Qiao, Meng; Wu, Chengyao; Wei, Qiang; Xu, Danfeng; Shen, Dan; Lu, Xin; Gao, Xu; Hou, Jianguo; Sun, Yinghao

    2014-11-30

    The current strategy for diagnosing prostate cancer (PCa) is mainly based on the serum prostate-specific antigen (PSA) test. However, PSA has low specificity and has led to numerous unnecessary biopsies. We evaluated the effectiveness of urinary metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), a long noncoding RNA, for predicting the risk of PCa before biopsy. The MALAT-1 score was tested in a discovery phase and a multi-center validation phase. The predictive power of the MALAT-1 score was evaluated by the area under receiver operating characteristic (ROC) curve (AUC) and by decision curve analysis. As an independent predictor of PCa, the MALAT-1 score was significantly higher in men with a positive biopsy than in those with a negative biopsy. The ROC analysis showed a higher AUC for the MALAT-1 score (0.670 and 0.742) vs. the total PSA (0.545 and 0.601) and percent free PSA (0.622 and 0.627) in patients with PSA values of 4.0-10 ng/ml. According to the decision curve analysis, using a probability threshold of 25%, the MALAT-1 model would prevent 30.2%-46.5% of unnecessary biopsies in PSA 4-10 ng/ml cohorts, without missing any high-grade cancers. Our results demonstrate that urine MALAT-1 is a promising biomarker for predicting prostate cancer risk.

  3. Down-regulation of MALAT1 inhibits cervical cancer cell invasion and metastasis by inhibition of epithelial-mesenchymal transition.

    PubMed

    Sun, Ruili; Qin, Changfei; Jiang, Binyuan; Fang, Shujuan; Pan, Xi; Peng, Li; Liu, Zhaoyang; Li, Wenling; Li, Yuehui; Li, Guancheng

    2016-03-01

    The metastasis-associated lung adenocarcinoma transcript 1(MALAT1), a member of the long non-coding RNA (lncRNA) family, has been reported to be highly enriched in many kinds of cancers and to be a metastasis marker and a prognostic factor. In this study, we found that MALAT1 expression levels were significantly increased in cervical cancer (CC) cells and tissues. The down-regulation of MALAT1 by shRNA in CC cells inhibited the invasion and metastasis in vitro and in vivo. Microarray analysis showed that the knockdown of MALAT1 up-regulated the epithelial markers E-cadherin and ZO-1, and down-regulated the mesenchymal markers β-catenin and Vimentin. This regulation was further confirmed by subsequent observation from RT-PCR, western blot, and immunofluorescence results. Meanwhile, the transcription factor snail, which functions to modulate epithelial-mesenchymal transition (EMT), was also down-regulated at both transcript and protein levels by MALAT1 down-regulation. In addition, we found that MALAT1 expression levels were positively related to HPV infection in cervical epithelial tissues by microarray analysis. Taken together, these results suggest that MALAT1 functions to promote cervical cancer invasion and metastasis via induction of EMT, and it may be a target for the prevention and therapy of cervical cancers.

  4. Long noncoding RNA MALAT1 promotes uveal melanoma cell growth and invasion by silencing of miR-140

    PubMed Central

    Sun, Lei; Sun, Peng; Zhou, Qi-ying; Gao, Xiangchun; Han, Qing

    2016-01-01

    Increasing evidences have demonstrated that long noncoding RNAs (LncRNAs) play a significant role in the development of tumor. However, the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in uveal melanoma remains unknown. In this study, we demonstrated that the expression of MALAT1 was upregulated in the uveal melanoma tissues compared to normal tissues. Among them, MALAT1 was upregulated in 72% (18/25) uveal melanoma tissues compared to their paired normal tissues. Knockdown of MALAT1 suppressed uveal melanoma cell proliferation, colony information, invasion and migration. Moreover, we showed that knockdown of MALAT1 promoted miR-140 expression and suppressed Slug and ADAM10 expression in the MUM-2C cell. In addition, we demonstrated that miR-140 was downregulated in the uveal melanoma tissues compared to normal tissues and cell lines. The expression level of MALAT1 was inversely correlated with the expression level of miR-140 in uveal melanoma tissues. These results suggested that MALAT1 served as an oncogenic LncRNA in the development of uveal melanoma. PMID:27725873

  5. Loss of the abundant nuclear non-coding RNA MALAT1 is compatible with life and development.

    PubMed

    Eißmann, Moritz; Gutschner, Tony; Hämmerle, Monika; Günther, Stefan; Caudron-Herger, Maïwen; Groß, Matthias; Schirmacher, Peter; Rippe, Karsten; Braun, Thomas; Zörnig, Martin; Diederichs, Sven

    2012-08-01

    The metastasis-associated lung adenocarcinoma transcript 1, MALAT1, is a long non-coding RNA (lncRNA) that has been discovered as a marker for lung cancer metastasis. It is highly abundant, its expression is strongly regulated in many tumor entities including lung adenocarcinoma and hepatocellular carcinoma as well as physiological processes, and it is associated with many RNA binding proteins and highly conserved throughout evolution. The nuclear transcript MALAT-1 has been functionally associated with gene regulation and alternative splicing and its regulation has been shown to impact proliferation, apoptosis, migration and invasion.   Here, we have developed a human and a mouse knockout system to study the loss-of-function phenotypes of this important ncRNA. In human tumor cells, MALAT1 expression was abrogated using Zinc Finger Nucleases. Unexpectedly, the quantitative loss of MALAT1 did neither affect proliferation nor cell cycle progression nor nuclear architecture in human lung or liver cancer cells. Moreover, genetic loss of Malat1 in a knockout mouse model did not give rise to any obvious phenotype or histological abnormalities in Malat1-null compared with wild-type animals. Thus, loss of the abundant nuclear long ncRNA MALAT1 is compatible with cell viability and normal development.

  6. The long noncoding RNA MALAT1 promotes tumor-driven angiogenesis by up-regulating pro-angiogenic gene expression.

    PubMed

    Tee, Andrew E; Liu, Bing; Song, Renhua; Li, Jinyan; Pasquier, Eddy; Cheung, Belamy B; Jiang, Cizhong; Marshall, Glenn M; Haber, Michelle; Norris, Murray D; Fletcher, Jamie I; Dinger, Marcel E; Liu, Tao

    2016-02-23

    Neuroblastoma is the most common solid tumor during early childhood. One of the key features of neuroblastoma is extensive tumor-driven angiogenesis due to hypoxia. However, the mechanism through which neuroblastoma cells drive angiogenesis is poorly understood. Here we show that the long noncoding RNA MALAT1 was upregulated in human neuroblastoma cell lines under hypoxic conditions. Conditioned media from neuroblastoma cells transfected with small interfering RNAs (siRNA) targeting MALAT1, compared with conditioned media from neuroblastoma cells transfected with control siRNAs, induced significantly less endothelial cell migration, invasion and vasculature formation. Microarray-based differential gene expression analysis showed that one of the genes most significantly down-regulated following MALAT1 suppression in human neuroblastoma cells under hypoxic conditions was fibroblast growth factor 2 (FGF2). RT-PCR and immunoblot analyses confirmed that MALAT1 suppression reduced FGF2 expression, and Enzyme-Linked Immunosorbent Assays revealed that transfection with MALAT1 siRNAs reduced FGF2 protein secretion from neuroblastoma cells. Importantly, addition of recombinant FGF2 protein to the cell culture media reversed the effects of MALAT1 siRNA on vasculature formation. Taken together, our data suggest that up-regulation of MALAT1 expression in human neuroblastoma cells under hypoxic conditions increases FGF2 expression and promotes vasculature formation, and therefore plays an important role in tumor-driven angiogenesis.

  7. The long noncoding RNA MALAT1 promotes tumor-driven angiogenesis by up-regulating pro-angiogenic gene expression.

    PubMed

    Tee, Andrew E; Liu, Bing; Song, Renhua; Li, Jinyan; Pasquier, Eddy; Cheung, Belamy B; Jiang, Cizhong; Marshall, Glenn M; Haber, Michelle; Norris, Murray D; Fletcher, Jamie I; Dinger, Marcel E; Liu, Tao

    2016-02-23

    Neuroblastoma is the most common solid tumor during early childhood. One of the key features of neuroblastoma is extensive tumor-driven angiogenesis due to hypoxia. However, the mechanism through which neuroblastoma cells drive angiogenesis is poorly understood. Here we show that the long noncoding RNA MALAT1 was upregulated in human neuroblastoma cell lines under hypoxic conditions. Conditioned media from neuroblastoma cells transfected with small interfering RNAs (siRNA) targeting MALAT1, compared with conditioned media from neuroblastoma cells transfected with control siRNAs, induced significantly less endothelial cell migration, invasion and vasculature formation. Microarray-based differential gene expression analysis showed that one of the genes most significantly down-regulated following MALAT1 suppression in human neuroblastoma cells under hypoxic conditions was fibroblast growth factor 2 (FGF2). RT-PCR and immunoblot analyses confirmed that MALAT1 suppression reduced FGF2 expression, and Enzyme-Linked Immunosorbent Assays revealed that transfection with MALAT1 siRNAs reduced FGF2 protein secretion from neuroblastoma cells. Importantly, addition of recombinant FGF2 protein to the cell culture media reversed the effects of MALAT1 siRNA on vasculature formation. Taken together, our data suggest that up-regulation of MALAT1 expression in human neuroblastoma cells under hypoxic conditions increases FGF2 expression and promotes vasculature formation, and therefore plays an important role in tumor-driven angiogenesis. PMID:26848616

  8. Clinical Significance of Long Non-coding RNA MALAT1 Expression in Tissue and Serum of Breast Cancer.

    PubMed

    Miao, Yufeng; Fan, Rengen; Chen, Lige; Qian, Haixin

    2016-07-01

    Long non-coding RNAs (lncRNAs) have been proven to serve a critical role in cancer development and progression. The aim of this study was to elucidate clinical significance of lncRNA MALAT1 expression in breast cancer (BC). A total of 78 BC patients treated with radical resection were enrolled in this study. Quantitative reverse transcription-polymerase chain reaction was used to detect MALAT1 expression in tissues and serum samples. The receiver operating characteristics (ROC) curve was constructed to describe diagnostic specificity and sensitivity. Lentivirus-mediated RNA interference was used to knockdown MALAT1 in the MDA-MB-231 cell line, and then cell proliferation and invasion were explored. Results showed that MALAT1 expression was significantly up-regulated in 85.9% (67/78) of cancerous tissues compared with normal counterparts (P<0.01). Further, an elevated MALAT1 expression in BC tissue was significantly associated with lymph metastasis (P=0.037) and adverse 5-year disease-free survival (mean 48.5 months vs 62.7 months, P=0.012). Suppression of lncRNA MALAT1 significantly inhibited BC cells proliferation, migration and invasion, induced apoptosis and cell cycle G1 arrest. In addition, serum MALAT1 levels in BC patients were much higher than levels in patients with benign breast disease (P<0.001), its diagnostic efficacy was satisfactory, area under the curve (AUC) was 0.833. In conclusion, MALAT1 upregulation plays an important rolein BC development, and serum MALAT1 level may be a potential tumor marker for BC diagnosis.

  9. Inhibition of the long non-coding RNA MALAT1 suppresses tumorigenicity and induces apoptosis in the human ovarian cancer SKOV3 cell line

    PubMed Central

    LIU, SHIPING; JIANG, XUAN; LI, WEIHUA; CAO, DONGYAN; SHEN, KENG; YANG, JIAXIN

    2016-01-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a 8,000 nucleotide-long, spliced non-coding RNA, which has been reported to be deregulated in several tumors. However, to the best of our knowledge, the role of MALAT1 in ovarian cancer has not been previously investigated. The aim of the present study was to investigate the effect of MALAT1 inhibition on the tumorigenity of SKOV3 cells. First, stable MALAT1-knockdown ovarian cancer cells and control cells were established using lentivirus-mediated artificial micro RNA interference in order to investigate the effect of MALAT1 inhibition on cell viability, clonability, migration, invasion and apoptosis in vitro. In addition, the effect of MALAT1 on cell growth in nude mice was assessed. To identify the possible targets of MALAT1, total RNA was extracted from MALAT1-knockdown cells and control cells and a microarray analysis was performed. The results showed that MALAT1 inhibition significantly suppressed tumorigenity in vitro and in vivo (P<0.01). Compared with the control cells, 921 genes in the MALAT1-knockdown cells were deregulated by at least two-fold. The results of the reverse transcription-quantitative polymerase chain reaction showed that 19 of the 20 genes selected for validation confirmed the deregulation indicated by the microarray analysis. The findings define a major oncogenic role for MALAT1, which may offer an attractive novel target for therapeutic intervention in ovarian cancer. PMID:27313681

  10. A cytotoxic principle of Tamarindus indica, di-n-butyl malate and the structure-activity relationship of its analogues.

    PubMed

    Kobayashi, A; Adenan, M I; Kajiyama, S; Kanzaki, H; Kawazu, K

    1996-01-01

    Bioassay-guided fractionation of the methanolic extract of Tamarindus indica fruits led to the isolation of L-(-)-di-n-butyl malate which exhibited a pronounced cytotoxic activity against sea urchin embryo cells. In order to study structure-activity relationships, close-structure relatives of di-n-butyl malate were synthesized using D-(+)- and L-(-)-malic acid as starting materials, and their cytotoxic activities were examined for the sea urchin embryo assay. L-(-)-Di-n-pentyl malate was the most effective inhibitor to the development of the fertilized eggs. Significant inhibitory activity was not seen in the esters of D-(-)-isomer.

  11. Role of the divalent metal ion in the NAD:malic enzyme reaction: an ESEEM determination of the ground state conformation of malate in the E:Mn:malate complex.

    PubMed Central

    Tipton, P. A.; Quinn, T. P.; Peisach, J.; Cook, P. F.

    1996-01-01

    The conformation of L-malate bound at the active site of Ascaris suum malic enzyme has been investigated by electron spin echo envelope modulation spectroscopy. Dipolar interactions between Mn2+ bound to the enzyme active site and deuterium specifically placed at the 2-position, the 3R-position, and the 3S-position of L-malate were observed. The intensities of these interactions are related to the distance between each deuterium and Mn2+. Several models of possible Mn-malate complexes were constructed using molecular graphics techniques, and conformational searches were conducted to identify conformers of malate that meet the distance criteria defined by the spectroscopic measurements. These searches suggest that L-malate binds to the enzyme active site in the trans conformation, which would be expected to be the most stable conformer in solution, not in the gauche conformer, which would be more similar to the conformation required for oxidative decarboxylation of oxalacetate formed from L-malate at the active site of the enzyme. PMID:8844853

  12. Overexpression of long non-coding RNA MALAT1 is correlated with clinical progression and unfavorable prognosis in pancreatic cancer.

    PubMed

    Pang, Er-Jun; Yang, Rui; Fu, Xi-bo; Liu, Ye-fu

    2015-04-01

    Long non-coding RNAs (lncRNAs) have been proved to serve as a critical role in cancer development and progression. However, little is known about the pathological role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in pancreatic cancer patients. The aims of this study are to measure the expression of lncRNA MALAT1 in pancreatic cancer patients and to explore the clinical significance of the lncRNA MALAT1. Using qRT-PCR, the expression of lncRNA MALAT1 was measured in 126 pancreatic cancer tissues and 15 adjacent non-cancerous tissues. In the present study, our results indicated that lncRNA MALAT1 was highly expressed in pancreatic cancer compared with adjacent non-cancerous tissues (P < 0.001), and positively correlated with clinical stage (early stages vs. advanced stages, P < 0.001), tumor size (<2 vs. ≥2 cm, P = 0.004), lymph node metastasis (negative vs. positive, P < 0.001), and distant metastasis (absent vs. present, P = 0.001) in pancreatic cancer patients. Furthermore, we also found that lncRNA MALAT1 overexpression was an unfavorable prognostic factor in pancreatic cancer patients (P < 0.001), regardless of clinical stage, tumor size, lymph node metastasis, and distant metastasis. Finally, increased lncRNA MALAT1 expression was an independent poor prognostic factor for pancreatic patients through multivariate analysis (P = 0.018). In conclusion, overexpression of lncRNA MALAT1 serves as an unfavorable prognostic biomarker in pancreatic cancer patients.

  13. Effect of abscisic and gibberellic acids on malate synthase transcripts in germinating castor bean seeds.

    PubMed

    Rodriguez, D; Dommes, J; Northcote, D H

    1987-05-01

    Several clones complementary to malate synthase mRNA have been identified in a complementary-DNA library to mRNA from castor bean endosperm. One of these clones has been used as a probe to measure levels of transcripts during seed germination and the effects of gibberellic acid and abscisic acid on these levels have been examined.Malate synthase transcripts increased during germination and GA3 advanced their appearance in the endosperm. Exogenously applied ABA inhibited the accumulation of transcripts over a time course of germination but the addition of GA3 counteracted its inhibitory effects. The data confirmed previous reports which indicated that the action of both growth regulators was on transcript accumulation and that there is a coordinated induction of the enzymes involved in the lipid metabolism in oil seeds.

  14. The varied functions of aluminium-activated malate transporters-much more than aluminium resistance.

    PubMed

    Palmer, Antony J; Baker, Alison; Muench, Stephen P

    2016-06-15

    The ALMT (aluminium-activated malate transporter) family comprises a functionally diverse but structurally similar group of ion channels. They are found ubiquitously in plant species, expressed throughout different tissues, and located in either the plasma membrane or tonoplast. The first family member identified was TaALMT1, discovered in wheat root tips, which was found to be involved in aluminium resistance by means of malate exudation into the soil. However, since this discovery other family members have been shown to have many other functions such as roles in stomatal opening, general anionic homoeostasis, and in economically valuable traits such as fruit flavour. Recent evidence has also shown that ALMT proteins can act as key molecular actors in GABA (γ-aminobutyric acid) signalling, the first evidence that GABA can act as a signal transducer in plants. PMID:27284052

  15. Long noncoding RNA MALAT1 promotes malignant development of esophageal squamous cell carcinoma by targeting β-catenin via Ezh2

    PubMed Central

    Wang, Wei; Zhu, Yunan; Li, Sanni; Chen, Xinfeng; Jiang, Guozhong; Shen, Zhibo; Qiao, Yamin; Wang, Liping; Zheng, Pengyuan; Zhang, Yi

    2016-01-01

    Evidences have shown that lncRNAs involve in the initiation and progression of various cancers including esophageal squamous cell carcinoma (ESCC). The aberrant expression of lncRNA MALAT1 was investigated in 106 paired ESCC tissues and adjacent non-cancerous tissues by qRT-PCR. Down-regulated MALAT1 and Ezh2 over-expression plasmid were constructed respectively to analyze the expression of β-catenin, Lin28 and Ezh2 genes. We found that the MALAT1 expression level was higher in human ESCC tissues (P=0.0011), which was closely correlated with WHO grade (P=0.0395, P=0.0331), lymph node metastasis (P=0.0213) and prognosis (P=0.0294). Silencing of MALAT1 expression inhibited cell proliferation, migration and tumor sphere formation, while increasing cell apoptosis of esophageal cancer in vitro. Down-regulation of MALAT1 decreased the expression of β-catenin, Lin28 and Ezh2 genes, while over-expressed Ezh2 combined with MALAT1 down-regulation completely reversed the si-MALAT1-mediated repression of β-catenin and Lin28 in esophageal cancer cells. Animal experiments showed that knockdown of MALAT1 decreased tumor formation and improved survival. MALAT1 promotes the initiation and progression of ESCC, suggesting that inhibition of MALAT1 might be a potential target for treatment of ESCC. PMID:27015363

  16. Evidence That a Malate/Inorganic Phosphate Exchange Translocator Imports Carbon across the Leucoplast Envelope for Fatty Acid Synthesis in Developing Castor Seed Endosperm.

    PubMed Central

    Eastmond, P. J.; Dennis, D. T.; Rawsthorne, S.

    1997-01-01

    In this study we examined the processes by which malate and pyruvate are taken up across the leucoplast envelope for fatty acid synthesis in developing castor (Ricinus communis L.) seed endosperm. Malate was taken up by isolated leucoplasts with a concentration dependence indicative of protein-mediated transport. The maximum rate of malate uptake was 704 [plus or minus] 41 nmol mg-1 protein h-1 and the Km was 0.62 [plus or minus] 0.08 mM. In contrast, the rate of pyruvate uptake increased linearly with respect to the substrate concentration and was 5-fold less than malate at a concentration of 5 mM. Malate uptake was inhibited by inorganic phosphate (Pi), glutamate, malonate, succinate, 2-oxoglutarate, and n-butyl malonate, an inhibitor of the mitochondrial malate/Pi-exchange translocator. Back-exchange experiments confirmed that malate was taken up by leucoplasts in counterexchange for Pi. The exchange stoichiometry was 1:1. The rate of malate-dependent fatty acid synthesis by isolated leucoplasts was 3-fold greater than from pyruvate at a concentration of 5 mM and was inhibited by n-butyl malonate. It is proposed that leucoplasts from developing castor endosperm contain a malate/Pi translocator that imports malate for fatty acid synthesis. This type of dicarboxylate transport activity has not been identified previously in plastids. PMID:12223747

  17. An Electrophoretic Analysis of the Isozymes of Malate Dehydrogenase in Several Different Plants 1

    PubMed Central

    Weimberg, Ralph

    1968-01-01

    The particulate and soluble fractions of cell-free extracts from seeds, roots, and leaves of 10 different plants were examined electrophoretically for isozymes of malate dehydrogenase. Distinct isozyme patterns were observed for each plant and even for the individual tissues of each species. There were some isozymes in several different plant extracts with equal electrophoretic mobilities, but there was no isozyme band that was common to all tissues or to all plants. Images PMID:16656816

  18. [Subcellular localization of isozymes of NAD-dependent malate dehydrogenase in sugar beet Beta vulgaris L].

    PubMed

    Iudina, R S; Levites, E V

    2008-12-01

    Subcellular localization of isozymes of NAD-dependent malate dehydrogenase (MDH) in sugar beet was studied. Isozymes ss and 11 controlled by loci Mdh2 and Mdh3, respectively, were shown to locate in mitochondria, whereas isozyme pp controlled by locus Mdh1, in microbodies. All examined samples lack hybrid MDH isozymes, which could testify to the interaction between products of nonallelic Mdh genes. This can be explained by the localization of nonallelic isozymes in various compartments of the cell and organelles.

  19. Malate plays a crucial role in starch metabolism, ripening, and soluble solid content of tomato fruit and affects postharvest softening.

    PubMed

    Centeno, Danilo C; Osorio, Sonia; Nunes-Nesi, Adriano; Bertolo, Ana L F; Carneiro, Raphael T; Araújo, Wagner L; Steinhauser, Marie-Caroline; Michalska, Justyna; Rohrmann, Johannes; Geigenberger, Peter; Oliver, Sandra N; Stitt, Mark; Carrari, Fernando; Rose, Jocelyn K C; Fernie, Alisdair R

    2011-01-01

    Despite the fact that the organic acid content of a fruit is regarded as one of its most commercially important quality traits when assessed by the consumer, relatively little is known concerning the physiological importance of organic acid metabolism for the fruit itself. Here, we evaluate the effect of modifying malate metabolism in a fruit-specific manner, by reduction of the activities of either mitochondrial malate dehydrogenase or fumarase, via targeted antisense approaches in tomato (Solanum lycopersicum). While these genetic perturbations had relatively little effect on the total fruit yield, they had dramatic consequences for fruit metabolism, as well as unanticipated changes in postharvest shelf life and susceptibility to bacterial infection. Detailed characterization suggested that the rate of ripening was essentially unaltered but that lines containing higher malate were characterized by lower levels of transitory starch and a lower soluble sugars content at harvest, whereas those with lower malate contained higher levels of these carbohydrates. Analysis of the activation state of ADP-glucose pyrophosphorylase revealed that it correlated with the accumulation of transitory starch. Taken together with the altered activation state of the plastidial malate dehydrogenase and the modified pigment biosynthesis of the transgenic lines, these results suggest that the phenotypes are due to an altered cellular redox status. The combined data reveal the importance of malate metabolism in tomato fruit metabolism and development and confirm the importance of transitory starch in the determination of agronomic yield in this species.

  20. HULC cooperates with MALAT1 to aggravate liver cancer stem cells growth through telomere repeat-binding factor 2

    PubMed Central

    Wu, Mengying; Lin, Zhuojia; Li, Xiaonan; Xin, Xiaoru; An, Jiahui; Zheng, Qidi; Yang, Yuxin; Lu, Dongdong

    2016-01-01

    The dysregulation of lncRNAs has increasingly been linked to many human diseases, especially in cancers. Our results demonstrate HULC, MALAT1 and TRF2 are highly expressed in human hepatocellular carcinoma tissues, and HULC plus MALAT1 overexpression drastically promotes the growth of liver cancer stem cells. Mechanistically, both HULC and MALAT1 overexpression enhanced RNA polII, P300, CREPT to load on the promoter region of telomere repeat-binding factor 2(TRF2), triggering the overexpression, phosphorylation and SUMOylation of TRF2. Strikingly, the excessive TRF2 interacts with HULC or MALAT1 to form the complex that loads on the telomeric region, replacing the CST/AAF and recruiting POT1, pPOT1, ExoI, SNM1B, HP1 α. Accordingly, the telomere is greatly protected and enlonged. Furthermore, the excessive HULC plus MALAT1 reduced the methylation of the TERC promoter dependent on TRF2, increasing the TERC expression that causes the increase of interplay between TRET and TERC. Ultimately, the interaction between RFC and PCNA or between CDK2 and CyclinE, the telomerase activity and the microsatellite instability (MSI) are significantly increased in the liver cancer stem cells. Our demonstrations suggest that haploinsufficiency of HULC/MALAT1 plays an important role in malignant growth of liver cancer stem cell. PMID:27782152

  1. L-Malate's Plasma and Excretion Profile in the Treatment of Moderate and Severe Hemorrhagic Shock in Rats

    PubMed Central

    Himmen, Stephan; Mueller, Friederike; Rohrig, Ricarda; Roehrborn, Friederike; Teloh, Johanna K.; de Groot, Herbert

    2016-01-01

    Introduction. Malate is a standard component in fluid therapy within a wide range of medical applications. To date, there are insufficient data regarding its plasma distribution, renal excretion, and metabolism after infusion. This study aimed to investigate these three aspects in a rat model of moderate and severe hemorrhagic shock (HS). Methods. Male Wistar rats were subjected to HS by dropping the mean arterial blood pressure to 25–30 mmHg (severe) and 40–45 mmHg (moderate), respectively, for 60 minutes. Subsequently, reperfusion with Ringer-saline or a malate containing crystalloid solution (7 mM, 13.6 mM, and 21 mM, resp.) was performed within 30 minutes, followed by an observation period of 150 minutes. Results. In the present experiments, malate rapidly disappeared from the blood, while only 5% of the infused malate was renally excreted. In the resuscitation interval the urinary citrate and succinate amounts significantly increased compared to control. Conclusion. Malate's half-life is between 30 and 60 minutes in both, moderate and severe HS. Thus, even under traumatic conditions malate seems to be subjected to rapid metabolism with participation of the kidneys. PMID:27403429

  2. Observation of cytoplasmic and vacuolar malate in maize root tips by sup 13 C-NMR spectroscopy. [Zea mays L

    SciTech Connect

    Chang, K.; Roberts, J.K.M. )

    1989-01-01

    The accumulation of malate by maize (Zea mays L.) root tips perfused with KH{sup 13}CO{sub 3} was followed by {sup 13}C nuclear magnetic resonance spectroscopy. In vivo nuclear magnetic resonance spectra contained distinct signals from two pools of malate in maize root tips, one at a pH {approximately}5.3 (assigned to the vacuole) and one at a pH > 6.5 (assigned to the cytoplasm). The ratio of cytoplasmic to vacuolar malate was lower in 12 millimeter long root tips than in 2 millimeter root tips. The relatively broad width of the signals from C1- and C4-labeled vacuolar malate indicated heterogeneity in vacuolar pH. During the 3 hour KH{sup 13}CO{sub 3} treatment, {sup 13}C-malate accumulated first primarily in the cytoplasm, increasing to a fairly constant level of {approximately}6 millimolar by 1 hour. After a lag, vacuolar malate increased throughout the experiment.

  3. Magnitude of malate-aspartate reduced nicotinamide adenine dinucleotide shuttle activity in intact respiring tumor cells.

    PubMed

    Greenhouse, W V; Lehninger, A L

    1977-11-01

    Measurements of respiration, CO2 and lactate production, and changes in the levels of various key metabolites of the glycolytic sequence and tricarboxylic acid cycle were made on five lines of rodent ascites tumor cells (two strains of Ehrlich ascites tumor cells, Krebs II carcinoma, AS-30D carcinoma, and L1210 cells) incubated aerobically in the presence of uniformly labeled D-[14C]glucose. From these data, as well as earlier evidence demonstrating that the reduced nicotinamide adenine dinucleotide (NADH) shuttle in these cells requires a transaminase step and is thus identified as the malate-aspartate shuttle (W.V.V. Greenhouse and A.L. Lehninger, Cancer Res., 36: 1392-1396, 1976), metabolic flux diagrams were constructed for the five cell lines. These diagrams show the relative rates of glycolysis, the tricarboxylic acid cycle, electron transport, and the malate-aspartate shuttle in these tumors. Large amounts of cytosolic NADH were oxidized by the mitochondrial respiratory chain via the NADH shuttle, comprising anywhere from about 20 to 80% of the total flow of reducing equivalents to oxygen in these tumors. Calculations of the sources of energy for adenosine triphosphate synthesis indicated that on the average about one-third of the respiratory adenosine triphosphate is generated by electron flow originating from cytosolic NADH via the malate-aspartate shuttle.

  4. Downregulation of long noncoding RNA MALAT1 induces epithelial-to-mesenchymal transition via the PI3K-AKT pathway in breast cancer.

    PubMed

    Xu, Shouping; Sui, Shiyao; Zhang, Jinfeng; Bai, Nanxia; Shi, Qingyu; Zhang, Guangwen; Gao, Song; You, Zilong; Zhan, Chao; Liu, Feng; Pang, Da

    2015-01-01

    The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) regulates cell motility via the transcriptional or post-transcriptional control of motility-related genes. Whether MALAT1 plays a critical role in cancer progression in breast cancer remains unclear. In this study, we found that MALAT1 was downregulated in breast tumor cell lines and cancer tissue, and showed that knockdown of MALAT1 in breast cancer cell lines induced an epithelial-to-mesenchymal transition (EMT) program via phosphatidylinositide-3 kinase-AKT pathways. Furthermore, lower expression of MALAT1 in breast cancer patients was associated with shorter relapse-free survival. Thus, our results indicate for the first time that MALAT1 is a novel regulator of EMT in breast cancer and may be a potential therapeutic target for breast cancer metastasis.

  5. Upregulation of MALAT-1 and its association with survival rate and the effect on cell cycle and migration in patients with esophageal squamous cell carcinoma.

    PubMed

    Yao, Wenjian; Bai, Yu; Li, Yan; Guo, Ling; Zeng, Ping; Wang, Yonglian; Qi, Bo; Liu, Shangguo; Qin, Xiuguang; Li, Yongzhen; Zhao, Baosheng

    2016-04-01

    The aim of this study is to investigate whether metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) can be used as a potential therapy target for human esophageal squamous cell carcinoma. MALAT-1 expression levels were detected in 137 paired EC samples and adjacent nonneoplastic tissues. Human esophageal carcinoma cell lines EC9706 and KYSE150 were transfected with MALAT-1 small interference RNA. Cell proliferation, migration/invasion ability, cell cycle, and apoptosis were assessed. MALAT-1 expressed higher levels in esophageal cancer tissues when compared with paired adjacent normal tissues. This high expression was associated with a decreased survival rate. MALAT-1 knockdown induced a decrease in proliferation-enhanced apoptosis, inhibited migration/invasion, and reduced colony formation and led to cell cycle arrest at the G2/M phase. These data indicates that MALAT-1 could be exploited for therapeutic benefit.

  6. Identification of Pseudomonas fluorescens chemotaxis sensory proteins for malate, succinate, and fumarate, and their involvement in root colonization.

    PubMed

    Oku, Shota; Komatsu, Ayaka; Nakashimada, Yutaka; Tajima, Takahisa; Kato, Junichi

    2014-01-01

    Pseudomonas fluorescens Pf0-1 exhibited chemotactic responses to l-malate, succinate, and fumarate. We constructed a plasmid library of 37 methyl-accepting chemotaxis protein (MCP) genes of P. fluorescens Pf0-1. To identify a MCP for l-malate, the plasmid library was screened using the PA2652 mutant of Pseudomonas aeruginosa PAO1, a mutant defective in chemotaxis to l-malate. The introduction of Pfl01_0728 and Pfl01_3768 genes restored the ability of the PA2652 mutant to respond to l-malate. The Pfl01_0728 and Pfl01_3768 double mutant of P. fluorescens Pf0-1 showed no response to l-malate or succinate, while the Pfl01_0728 single mutant did not respond to fumarate. These results indicated that Pfl01_0728 and Pfl01_3768 were the major MCPs for l-malate and succinate, and Pfl01_0728 was also a major MCP for fumarate. The Pfl01_0728 and Pfl01_3768 double mutant unexpectedly exhibited stronger responses toward the tomato root exudate and amino acids such as proline, asparagine, methionine, and phenylalanine than those of the wild-type strain. The ctaA, ctaB, ctaC (genes of the major MCPs for amino acids), Pfl01_0728, and Pfl01_3768 quintuple mutant of P. fluorescens Pf0-1 was less competitive than the ctaA ctaB ctaC triple mutant in competitive root colonization, suggesting that chemotaxis to l-malate, succinate, and/or fumarate was involved in tomato root colonization by P. fluorescens Pf0-1.

  7. Identification of Pseudomonas fluorescens Chemotaxis Sensory Proteins for Malate, Succinate, and Fumarate, and Their Involvement in Root Colonization

    PubMed Central

    Oku, Shota; Komatsu, Ayaka; Nakashimada, Yutaka; Tajima, Takahisa; Kato, Junichi

    2014-01-01

    Pseudomonas fluorescens Pf0-1 exhibited chemotactic responses to l-malate, succinate, and fumarate. We constructed a plasmid library of 37 methyl-accepting chemotaxis protein (MCP) genes of P. fluorescens Pf0-1. To identify a MCP for l-malate, the plasmid library was screened using the PA2652 mutant of Pseudomonas aeruginosa PAO1, a mutant defective in chemotaxis to l-malate. The introduction of Pfl01_0728 and Pfl01_3768 genes restored the ability of the PA2652 mutant to respond to l-malate. The Pfl01_0728 and Pfl01_3768 double mutant of P. fluorescens Pf0-1 showed no response to l-malate or succinate, while the Pfl01_0728 single mutant did not respond to fumarate. These results indicated that Pfl01_0728 and Pfl01_3768 were the major MCPs for l-malate and succinate, and Pfl01_0728 was also a major MCP for fumarate. The Pfl01_0728 and Pfl01_3768 double mutant unexpectedly exhibited stronger responses toward the tomato root exudate and amino acids such as proline, asparagine, methionine, and phenylalanine than those of the wild-type strain. The ctaA, ctaB, ctaC (genes of the major MCPs for amino acids), Pfl01_0728, and Pfl01_3768 quintuple mutant of P. fluorescens Pf0-1 was less competitive than the ctaA ctaB ctaC triple mutant in competitive root colonization, suggesting that chemotaxis to l-malate, succinate, and/or fumarate was involved in tomato root colonization by P. fluorescens Pf0-1. PMID:25491753

  8. Downregulation of lncRNA-MALAT1 Affects Proliferation and the Expression of Stemness Markers in Glioma Stem Cell Line SHG139S.

    PubMed

    Han, Yong; Zhou, Liang; Wu, Tingfeng; Huang, Yulun; Cheng, Zhe; Li, Xuetao; Sun, Ting; Zhou, Youxin; Du, Ziwei

    2016-10-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is among the most abundant and highly conserved lncRNAs, which has been detected in a wide variety of human tumors, including gastric cancer, gallbladder cancer, and so on. Previous research has showed that MALAT1 can activate LTBP3 gene in mesenchymal stem cells. However, the specific roles of MALAT1 in glioma stem cells (GSCs) remain unclear. In this study, we aimed to identify the effects of MALAT1 on proliferation and the expression of stemness markers on glioma stem cell line SHG139S. Our results showed that downregulation of MALAT1 suppressed the expression of Sox2 and Nestin which are related to stemness, while downregulation of MALAT1 promoted the proliferation in SHG139S. Further research on the underlying mechanism showed that the effects of MALAT1 downregulation on SHG139S were through regulating ERK/MAPk signaling activity. And we also found that downregulation of MALAT1 could activate ERK/MAPK signaling and promoted proliferation in SHG139 cells. These findings show that MALAT1 plays an important role in regulating the expression of stemness markers and proliferation of SHG139S, and provide a new research direction to target the progression of GSCs.

  9. Long Non Coding RNA MALAT1 Promotes Tumor Growth and Metastasis by inducing Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma.

    PubMed

    Zhou, Xuan; Liu, Su; Cai, Guoshuai; Kong, Lingping; Zhang, Tingting; Ren, Yu; Wu, Yansheng; Mei, Mei; Zhang, Lun; Wang, Xudong

    2015-11-02

    The prognosis of advanced oral squamous cell carcinoma (OSCC) patients remains dismal, and a better understanding of the underlying mechanisms is critical for identifying effective targets with therapeutic potential to improve the survival of patients with OSCC. This study aims to clarify the clinical and biological significance of metastasis-associated long non-coding RNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in OSCC. We found that MALAT1 is overexpressed in OSCC tissues compared to normal oral mucosa by real-time PCR. MALAT1 served as a new prognostic factor in OSCC patients. When knockdown by small interfering RNA (siRNA) in OSCC cell lines TSCCA and Tca8113, MALAT1 was shown to be required for maintaining epithelial-mesenchymal transition (EMT) mediated cell migration and invasion. Western blot and immunofluorescence staining showed that MALAT1 knockdown significantly suppressed N-cadherin and Vimentin expression but induced E-cadherin expression in vitro. Meanwhile, both nucleus and cytoplasm levels of β-catenin and NF-κB were attenuated, while elevated MALAT1 level triggered the expression of β-catenin and NF-κB. More importantly, targeting MALAT1 inhibited TSCCA cell-induced xenograft tumor growth in vivo. Therefore, these findings provide mechanistic insight into the role of MALAT1 in regulating OSCC metastasis, suggesting that MALAT1 is an important prognostic factor and therapeutic target for OSCC.

  10. Long Non-Coding RNA MALAT1 Mediates Transforming Growth Factor Beta1-Induced Epithelial-Mesenchymal Transition of Retinal Pigment Epithelial Cells

    PubMed Central

    Yang, Shuai; Yao, Haipei; Li, Min; Li, Hui; Wang, Fang

    2016-01-01

    Purpose To study the role of long non-coding RNA (lncRNA) MALAT1 in transforming growth factor beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells. Methods ARPE-19 cells were cultured and exposed to TGF-β1. The EMT of APRE-19 cells is confirmed by morphological change, as well as the increased expression of alpha-smooth muscle actin (αSMA) and fibronectin, and the down-regulation of E-cadherin and Zona occludin-1(ZO-1) at both mRNA and protein levels. The expression of lncRNA MALAT1 in RPE cells were detected by quantitative real-time PCR. Knockdown of MALAT1 was achieved by transfecting a small interfering RNA (SiRNA). The effect of inhibition of MALAT1 on EMT, migration, proliferation, and TGFβ signalings were observed. MALAT1 expression was also detected in primary RPE cells incubated with proliferative vitreoretinopathy (PVR) vitreous samples. Results The expression of MALAT1 is significantly increased in RPE cells incubated with TGFβ1. MALAT1 silencing attenuates TGFβ1-induced EMT, migration, and proliferation of RPE cells, at least partially through activating Smad2/3 signaling. MALAT1 is also significantly increased in primary RPE cells incubated with PVR vitreous samples. Conclusion LncRNA MALAT1 is involved in TGFβ1-induced EMT of human RPE cells and provides new understandings for the pathogenesis of PVR. PMID:27019196

  11. Plasma long non-coding RNA MALAT1 is associated with distant metastasis in patients with epithelial ovarian cancer

    PubMed Central

    Chen, Qingjuan; Su, Yongyong; He, Xiaopeng; Zhao, Weian; Wu, Caixia; Zhang, Weibo; Si, Xiaomin; Dong, Bingwei; Zhao, Lianying; Gao, Yufang; Yang, Xiaowen; Chen, Jianhui; Lu, Jian; Qiao, Ximin; Zhang, Yuchen

    2016-01-01

    Human metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a newly identified metastasis-associated long non-coding RNA. In a previous study, it was identified that plasma levels of MALAT1 were significantly increased in gastric cancer patients with metastasis compared with gastric cancer patients without metastasis and healthy control individuals. However, it is unclear whether plasma levels of MALAT1 may act as a biomarker for evaluating the development of metastasis in epithelial ovarian cancer (EOC). In the present study, groups that consisted of 47 patients with EOC and metastasis (EOC/DM), 47 patients with EOC without metastasis (EOC/NDM), and 47 healthy control (HC) individuals were established. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the level of plasma MALAT1 in these groups. The results showed that levels of plasma MALAT1 were significantly increased in the EOC/DM group compared with the EOC/NDM and HC groups (P<0.001). Receiver operating characteristic (ROC) analysis indicated that plasma MALAT1 yielded an area under the curve (AUC) of 0.820 [95% confidence interval (CI), 0.734–0.905; P<0.001], distinguishing between EOC/DM and EOC/NDM. ROC analysis also yielded an AUC of 0.884 (95% CI, 0.820–0.949; P<0.001), with 89.4% sensitivity and 72.3% specificity for distinguishing between EOC/DM and HC. Furthermore, multivariate analysis indicated that overexpression of MALAT1, differentiation (poor), tumor-node-metastasis stage (IV), lymph node metastasis (N3), peritoneal invasion (present) and higher serum carbohydrate antigen 125 levels were independent predictors of survival (hazard ratio, 3.322; P=0.028) in patients with EOC. Kaplan-Meier analysis revealed that patients with increased MALAT1 expression had a poorer disease-free survival time. In conclusion, the levels of plasma MALAT1 may act as a valuable biomarker for the diagnosis of metastasis. PMID:27446438

  12. LncRNA MALAT1 overexpression is an unfavorable prognostic factor in human cancer: evidence from a meta-analysis.

    PubMed

    Zhang, Jun; Zhang, Bingya; Wang, Tiejun; Wang, Hongyong

    2015-01-01

    Long non-coding RNAs (lncRNAs) have been suggested to serve as an important role in tumor development and progression. The aim of this study was to analyse the association between lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and cancer patients' overall survival. We systematically and carefully searched the studies from electronic databases and seriously identified according to eligibility criteria. The correlation between lncRNA MALAT1 expression and overall survival in human cancers was evaluated through Review Manager. A total of 8 studies which included 792 cancer patients were included in the final analysis. Meta-analysis showed that lncRNA MALAT1 overexpression was correlated with a poor overall survival and the pooled hazard ratio (HR) and corresponding 95% confidence interval (CI) was 1.94 (95% CI 1.59-2.38). From subgroup analyses, we present evidence that lncRNA MALAT1 overexpression was an unfavorable prognostic factor for patients' overall survival in non-small cell lung cancer and pancreatic cancer, the pooled HRs (95% CI) were 1.86 (95% CI 1.27-2.73) and 1.78 (95% CI 1.30-2.44), respectively. In conclusion, lncRNA MALAT1 is a potential prognostic factor in human cancers.

  13. Mutual inhibition between YAP and SRSF1 maintains long non-coding RNA, Malat1-induced tumourigenesis in liver cancer.

    PubMed

    Wang, Jiayi; Wang, Hongmei; Zhang, Yue; Zhen, Ni; Zhang, Li; Qiao, Yongxia; Weng, Wenhao; Liu, Xiangfan; Ma, Lifang; Xiao, Weifan; Yu, Wenjun; Chu, Qinghua; Pan, Qiuhui; Sun, Fenyong

    2014-05-01

    Emerging studies have revealed that Malat1 is overexpressed in many malignant diseases, including liver cancer, and contributes to enhancing cell migration or facilitating proliferation. However, the mechanism underlying its regulation has largely remained elusive. Here, we characterised the oncoprotein Yes-associated protein (YAP), which up-regulated metastasis-associated lung adenocarcinoma transcript 1 (Malat1) expression at both transcriptional and post-transcriptional levels, whereas serine/arginine-rich splicing factor 1 (SRSF1) played an opposing role. SRSF1 inhibited YAP activity by preventing its co-occupation with TCF/β-catenin on the Malat1 promoter. In contrast, overexpression of YAP impaired the nuclear retention of both SRSF1 and itself via an interaction with Angiomotin (AMOT). This effect removed the inhibitory role of SRSF1 on Malat1 in the nucleus. Furthermore, higher expression of YAP was consistent with a lower SRSF1 nuclear accumulation in human liver cancer tissues. We also revealed that overexpression of YAP combined with a knockdown of SRSF1 resulted in conspicuously enhanced transwell cell mobility, accelerated tumour growth rate, and loss of body weight in a tail vein-injected mouse models. Taken together, these data provided a novel mechanism underlying the balance between SRSF1, YAP and Malat1 and uncovered a new role of YAP in regulating long non-coding RNA (lncRNA). Thus, disrupting the interaction between YAP and SRSF1 may serve as a crucial therapeutic method in liver cancer.

  14. Elevated expression level of long noncoding RNA MALAT-1 facilitates cell growth, migration and invasion in pancreatic cancer.

    PubMed

    Jiao, Feng; Hu, Hai; Yuan, Cuncun; Wang, Lei; Jiang, Weihua; Jin, Ziliang; Guo, Zhen; Wang, Liwei

    2014-12-01

    Pancreatic cancer is one of the most aggressive solid malignancies with a dismal survival rate. Recent studies have shown that high expression levels of long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1) correlate with several solid tumors. However, the underlying molecular mechanisms and its clinical significance in pancreatic cancer remain to be elucidated. In the present study, our results showed that MALAT-1 expression levels were upregulated in pancreatic cancer tissues compared with adjacent noncancerous controls. Consistently, higher expression level of MALAT-1 was found in all seven pancreatic cancer cell lines relative to the human pancreatic ductal epithelial cell. Further function analysis revealed that downregulation of MALAT-1 could inhibit tumor cell proliferation and decrease cell migration and invasion in vitro. The underlying mechanisms are possibly involved in inducing G2/M cell cycle arrest, promoting cell apoptosis, suppressing epithelial-mesenchymal transition and reducing cancer stem-like properties. In conclusion, this study indicated that MALAT-1 may serve as an oncogenic lncRNA that is involved in malignancy phenotypes of pancreatic cancer. Therefore, it may be used as a potential therapeutic target.

  15. GABA Production in Lactococcus lactis Is Enhanced by Arginine and Co-addition of Malate.

    PubMed

    Laroute, Valérie; Yasaro, Chonthicha; Narin, Waranya; Mazzoli, Roberto; Pessione, Enrica; Cocaign-Bousquet, Muriel; Loubière, Pascal

    2016-01-01

    Lactococcus lactis NCDO 2118 was previously selected for its ability to decarboxylate glutamate to γ-aminobutyric acid (GABA), an interesting nutritional supplement able to improve mood and relaxation. Amino acid decarboxylation is generally considered as among the biochemical systems allowing lactic acid bacteria to counteracting acidic stress and obtaining metabolic energy. These strategies also include arginine deiminase pathway and malolactic fermentation but little is known about their possible interactions of with GABA production. In the present study, the effects of glutamate, arginine, and malate (i.e., the substrates of these acid-resistance pathways) on L. lactis NCDO 2118 growth and GABA production performances were analyzed. Both malate and arginine supplementation resulted in an efficient reduction of acidity and improvement of bacterial biomass compared to glutamate supplementation. Glutamate decarboxylation was limited to narrow environmental conditions (pH < 5.1) and physiological state (stationary phase). However, some conditions were able to improve GABA production or activate glutamate decarboxylation system even outside of this compass. Arginine clearly stimulated glutamate decarboxylation: the highest GABA production (8.6 mM) was observed in cultures supplemented with both arginine and glutamate. The simultaneous addition of arginine, malate, and glutamate enabled earlier GABA production (i.e., during exponential growth) at relatively high pH (6.5). As far as we know, no previous study has reported GABA production in such conditions. Although further studies are needed to understand the molecular basis of these phenomena, these results represent important keys suitable of application in GABA production processes. PMID:27458444

  16. GABA Production in Lactococcus lactis Is Enhanced by Arginine and Co-addition of Malate

    PubMed Central

    Laroute, Valérie; Yasaro, Chonthicha; Narin, Waranya; Mazzoli, Roberto; Pessione, Enrica; Cocaign-Bousquet, Muriel; Loubière, Pascal

    2016-01-01

    Lactococcus lactis NCDO 2118 was previously selected for its ability to decarboxylate glutamate to γ-aminobutyric acid (GABA), an interesting nutritional supplement able to improve mood and relaxation. Amino acid decarboxylation is generally considered as among the biochemical systems allowing lactic acid bacteria to counteracting acidic stress and obtaining metabolic energy. These strategies also include arginine deiminase pathway and malolactic fermentation but little is known about their possible interactions of with GABA production. In the present study, the effects of glutamate, arginine, and malate (i.e., the substrates of these acid-resistance pathways) on L. lactis NCDO 2118 growth and GABA production performances were analyzed. Both malate and arginine supplementation resulted in an efficient reduction of acidity and improvement of bacterial biomass compared to glutamate supplementation. Glutamate decarboxylation was limited to narrow environmental conditions (pH < 5.1) and physiological state (stationary phase). However, some conditions were able to improve GABA production or activate glutamate decarboxylation system even outside of this compass. Arginine clearly stimulated glutamate decarboxylation: the highest GABA production (8.6 mM) was observed in cultures supplemented with both arginine and glutamate. The simultaneous addition of arginine, malate, and glutamate enabled earlier GABA production (i.e., during exponential growth) at relatively high pH (6.5). As far as we know, no previous study has reported GABA production in such conditions. Although further studies are needed to understand the molecular basis of these phenomena, these results represent important keys suitable of application in GABA production processes. PMID:27458444

  17. Molecular cloning, purification and immunogenicity of recombinant Brucella abortus 544 malate dehydrogenase protein.

    PubMed

    Reyes, Alisha Wehdnesday Bernardo; Simborio, Hannah Leah Tadeja; Hop, Huynh Tan; Arayan, Lauren Togonon; Kim, Suk

    2016-03-01

    The Brucella mdh gene was successfully cloned and expressed in E. coli. The purified recombinant malate dehydrogenase protein (rMDH) was reactive to Brucella-positive bovine serum in the early stage, but not reactive in the middle or late stage, and was reactive to Brucella-positive mouse serum in the late stage, but not in the early or middle stage of infection. In addition, rMDH did not react with Brucella-negative bovine or mouse sera. These results suggest that rMDH has the potential for use as a specific antigen in serological diagnosis for early detection of bovine brucellosis.

  18. Molecular cloning, purification and immunogenicity of recombinant Brucella abortus 544 malate dehydrogenase protein

    PubMed Central

    Reyes, Alisha Wehdnesday Bernardo; Simborio, Hannah Leah Tadeja; Hop, Huynh Tan; Arayan, Lauren Togonon

    2016-01-01

    The Brucella mdh gene was successfully cloned and expressed in E. coli. The purified recombinant malate dehydrogenase protein (rMDH) was reactive to Brucella-positive bovine serum in the early stage, but not reactive in the middle or late stage, and was reactive to Brucella-positive mouse serum in the late stage, but not in the early or middle stage of infection. In addition, rMDH did not react with Brucella-negative bovine or mouse sera. These results suggest that rMDH has the potential for use as a specific antigen in serological diagnosis for early detection of bovine brucellosis. PMID:27051349

  19. Long non-coding RNA MALAT-1 is downregulated in preeclampsia and regulates proliferation, apoptosis, migration and invasion of JEG-3 trophoblast cells

    PubMed Central

    Chen, Haiying; Meng, Tao; Liu, Xuemin; Sun, Manni; Tong, Chunxiao; Liu, Jing; Wang, He; Du, Juan

    2015-01-01

    Long non-coding RNA (lncRNA), as a newly identified subset of the transcriptome, has been implicated in a variety of physiological and pathological processes. Metastasis associated lung adenocarcinoma transcript-1 (MALAT-1), a lncRNA that was initially detected in the metastatic lung cancer, was reported to be overexpressed in placenta previa increta/percreta (I/P), which is caused by excessive trophoblast invasion. However, the role of MALAT-1 in the regulation of trophoblast behavior is not fully understood. In this study, we first examined the expression of MALAT-1 in the placentas from the patients with preeclampsia, the pathology of which is associated with inadequate trophoblast invasion, and found that the expression of MALAT-1 was downregulated in the preeclamptic placentas as compared to the normal placentas. We further investigated the function of MALAT-1 in JEG-3 trophoblast cell line using short interfering RNA (siRNA) against MALAT-1 transcripts. Silencing of MALAT-1 in JEG-3 cells suppressed proliferation and induced cell cycle arrest at G0/G1 phase. Reduced expression of MALAT-1 by RNA interference resulted in enhanced apoptosis in JEG-3 cells, accompanied with elevated levels of the pro-apoptotic proteins including cleaved caspase-3, cleaved caspase-9 and cleaved poly (ADP-ribose) polymerase-1 (PARP-1). Moreover, the migration rate and the invasiveness of JEG-3 cells were suppressed when MALAT-1 was downregulated. In summary, our results suggest that MALAT-1 may play an important role in the regulation of proliferation, cell cycle, apoptosis, migration and invasion of trophoblast cells, and under-expression of MALAT-1 during early placentation may be involved in the pathogenesis of preeclampsia. PMID:26722461

  20. Long non-coding RNA MALAT-1 is downregulated in preeclampsia and regulates proliferation, apoptosis, migration and invasion of JEG-3 trophoblast cells.

    PubMed

    Chen, Haiying; Meng, Tao; Liu, Xuemin; Sun, Manni; Tong, Chunxiao; Liu, Jing; Wang, He; Du, Juan

    2015-01-01

    Long non-coding RNA (lncRNA), as a newly identified subset of the transcriptome, has been implicated in a variety of physiological and pathological processes. Metastasis associated lung adenocarcinoma transcript-1 (MALAT-1), a lncRNA that was initially detected in the metastatic lung cancer, was reported to be overexpressed in placenta previa increta/percreta (I/P), which is caused by excessive trophoblast invasion. However, the role of MALAT-1 in the regulation of trophoblast behavior is not fully understood. In this study, we first examined the expression of MALAT-1 in the placentas from the patients with preeclampsia, the pathology of which is associated with inadequate trophoblast invasion, and found that the expression of MALAT-1 was downregulated in the preeclamptic placentas as compared to the normal placentas. We further investigated the function of MALAT-1 in JEG-3 trophoblast cell line using short interfering RNA (siRNA) against MALAT-1 transcripts. Silencing of MALAT-1 in JEG-3 cells suppressed proliferation and induced cell cycle arrest at G0/G1 phase. Reduced expression of MALAT-1 by RNA interference resulted in enhanced apoptosis in JEG-3 cells, accompanied with elevated levels of the pro-apoptotic proteins including cleaved caspase-3, cleaved caspase-9 and cleaved poly (ADP-ribose) polymerase-1 (PARP-1). Moreover, the migration rate and the invasiveness of JEG-3 cells were suppressed when MALAT-1 was downregulated. In summary, our results suggest that MALAT-1 may play an important role in the regulation of proliferation, cell cycle, apoptosis, migration and invasion of trophoblast cells, and under-expression of MALAT-1 during early placentation may be involved in the pathogenesis of preeclampsia.

  1. Thin-film a-Si:H solar cells processed on aluminum-induced texture (AIT) glass superstrates: prediction of light absorption enhancement.

    PubMed

    Sahraei, Nasim; Peters, Marius; Venkataraj, Selvaraj; Aberle, Armin G; Calnan, Sonya; Ring, Sven; Stannowski, Bernd; Schlatmann, Rutger; Stangl, Rolf

    2015-05-10

    Light scattering superstrates are important for thin-film a-Si:H solar cells. In this work, aluminum-induced texture (AIT) glass, covered with nonetched Al-doped ZnO (AZO), is investigated as an alternative to the commonly used planar glass with texture-etched AZO superstrate. Four different AIT glasses with different surface roughnesses and different lateral feature sizes are investigated for their effects on light trapping in a-Si:H solar cells. For comparison, two reference superstrates are investigated as well: planar glass covered with nonetched AZO and planar glass covered with texture-etched AZO. Single-junction a-Si:H solar cells are deposited onto each superstrate, and the scattering properties (haze and angular resolved scattering) as well as the solar cell characteristics (current-voltage and external quantum efficiency) are measured and compared. The results indicate that AIT glass superstrates with nonetched AZO provide similar, or even superior, light trapping than the standard reference superstrate, which is demonstrated by a higher short-circuit current Jsc and a higher external quantum efficiency. Using the trapped light fraction δ, a quantity based on the integrated light scattering at the AZO/a-Si:H interface, we show that Jsc linearly increases with δ in the scattering regime of the samples, regardless of the type of superstrate used. PMID:25967490

  2. Construction of malate-sensing Escherichia coli by introduction of a novel chimeric two-component system.

    PubMed

    Ganesh, Irisappan; Ravikumar, Sambandam; Yoo, Ik-Keun; Hong, Soon Ho

    2015-04-01

    In an attempt to develop a high-throughput screening system for screening microorganisms which produce high amounts of malate, a MalKZ chimeric HK-based biosensor was constructed. Considering the sequence similarity among Escherichia coli (E. coli) MalK with Bacillus subtilis MalK and E. coli DcuS, the putative sensor domain of MalK was fused with the catalytic domain of EnvZ. The chimeric MalK/EnvZ TCS induced the ompC promoter through the cognate response regulator, OmpR, in response to extracellular malate. Real-time quantitative PCR and GFP fluorescence studies showed increased ompC gene expression and GFP fluorescence as malate concentration increased. By using this strategy, various chimeric TCS-based bacteria biosensors can be constructed, which may be used for the development of biochemical-producing recombinant microorganisms.

  3. Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise in advanced weightlifters.

    PubMed

    Wax, Benjamin; Kavazis, Andreas N; Weldon, Kevin; Sperlak, Joseph

    2015-03-01

    The purpose of this investigation was to test the efficacy of citrulline malate supplementation on exercise performance, blood lactate, heart rate, and blood pressure during lower-body dynamic resistance exercise. We hypothesized that citrulline malate ingestion before performing submaximal repeated bouts of multiple lower-body resistance exercises would improve performance. Twelve advanced resistance-trained male subjects participated in a randomized, counterbalanced, double-blind study. Subjects were randomly assigned to placebo (PL) or citrulline malate (8 g) groups and then performed repeated bouts of multiple lower-body resistance exercise. Specifically, subjects performed 5 sequential sets (60% 1 repetition maximum) to failure on the leg press, hack squat, and leg extension machines. Blood lactate, heart rate, systolic blood pressure, and diastolic blood pressure were determined before and after exercise. The exercise protocol resulted in sequential significant (p ≤ 0.05) decrease in the number of repetitions in all 3 exercises. However, subjects in the citrulline malate group performed significantly (p ≤ 0.05) higher number of repetitions during all 3 exercises compared with PL group. Blood lactate and heart rate were significantly increased (p ≤ 0.05) after exercise compared with before exercise but were not significantly different between citrulline malate and PL (p > 0.05). No significant (p > 0.05) differences were detected for blood pressure measurements. In conclusion, our results suggest that citrulline malate supplementation may be beneficial in improving exercise performance during lower-body multiple-bout resistance exercise in advanced resistance-trained men.

  4. Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise in advanced weightlifters.

    PubMed

    Wax, Benjamin; Kavazis, Andreas N; Weldon, Kevin; Sperlak, Joseph

    2015-03-01

    The purpose of this investigation was to test the efficacy of citrulline malate supplementation on exercise performance, blood lactate, heart rate, and blood pressure during lower-body dynamic resistance exercise. We hypothesized that citrulline malate ingestion before performing submaximal repeated bouts of multiple lower-body resistance exercises would improve performance. Twelve advanced resistance-trained male subjects participated in a randomized, counterbalanced, double-blind study. Subjects were randomly assigned to placebo (PL) or citrulline malate (8 g) groups and then performed repeated bouts of multiple lower-body resistance exercise. Specifically, subjects performed 5 sequential sets (60% 1 repetition maximum) to failure on the leg press, hack squat, and leg extension machines. Blood lactate, heart rate, systolic blood pressure, and diastolic blood pressure were determined before and after exercise. The exercise protocol resulted in sequential significant (p ≤ 0.05) decrease in the number of repetitions in all 3 exercises. However, subjects in the citrulline malate group performed significantly (p ≤ 0.05) higher number of repetitions during all 3 exercises compared with PL group. Blood lactate and heart rate were significantly increased (p ≤ 0.05) after exercise compared with before exercise but were not significantly different between citrulline malate and PL (p > 0.05). No significant (p > 0.05) differences were detected for blood pressure measurements. In conclusion, our results suggest that citrulline malate supplementation may be beneficial in improving exercise performance during lower-body multiple-bout resistance exercise in advanced resistance-trained men. PMID:25226311

  5. Regulation of MALAT1 expression by TDP43 controls the migration and invasion of non-small cell lung cancer cells in vitro.

    PubMed

    Guo, Fengjie; Jiao, Feng; Song, Zuoqing; Li, Shujun; Liu, Bin; Yang, Hongwei; Zhou, Qinghua; Li, Zhigang

    2015-09-18

    MALAT1 is a non-coding RNA overexpressed in non-small cell lung cancer (NSCLC). TDP-43 is a ubiquitously expressed, MALAT1-binding protein implicated in cancer development. We hypothesized that MALAT1 expression level is regulated in lung cancer by TDP-43. We analyzed their functions in cultured NSCLC cells. Downregulation of MALAT1 or TDP-43 expression by siRNA not only markedly suppressed NSCLC cell growth, as measured by the MTT assay in vitro cultured NSCLC cells (P < 0.05), but also noticeably impaired the migration and invasion of NSCLC cells, as analyzed by the migration and invasion assay. We also confirm that TDP-43 directly bound to MALAT1 RNA by a RNA immunoprecipitation (RIP) assay and by luciferase reporter activity assay. In a RT-PCR assay, silencing TDP-43 expression effectively decreased MALAT1 RNA transcript level. In contrast, TDP-43 overexpression markedly increased MALAT1 transcript level. In summary, these findings demonstrated that MALAT1 expression by regulation of TDP-43 controls cellular growth, migration, and invasion of NSCLCs.

  6. Role of MALAT1 as a Prognostic Factor for Survival in Various Cancers: A Systematic Review of the Literature with Meta-Analysis

    PubMed Central

    Wei, Yao; Niu, Ben

    2015-01-01

    Objectives. The expression of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a highly abundant and ubiquitously expressed long noncoding RNA (lncRNA), influences clinical parameters and may have prognostic value in cancer. This meta-analysis evaluated the prognostic role of MALAT1 in various cancers. Materials and Methods. Systematic literature searches of PubMed and EMBASE databases were conducted for eligible studies of the prognostic role of MALAT1 in cancer. Overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) were analyzed. Summary hazard ratios (HRs) and 95% confidence intervals (95% CIs) were assessed to evaluate the influence of MALAT1 expression on patient prognosis. Results. Nine studies with a total of 932 patients were included in the analysis. Elevated MALAT1 expression was significantly correlated with poor OS (HR 2.02; 95% CI: 1.62–2.52; P < 0.001; I2 = 0%). Subgroup analysis indicated that tumor type, histology type, ethnicity, and measurement technique did not affect the prognostic value of MALAT1 for OS. The HR of elevated MALAT1 for DFS was 2.78 (95% CI: 1.87–4.15; P < 0.001; I2 = 0%). Conclusions. Elevated MALAT1 expression is correlated with poor OS in various types of cancer, suggesting that this gene is a prognostic factor for different types of cancer. PMID:26420912

  7. MALAT1 functions as a competing endogenous RNA to mediate Rac1 expression by sequestering miR-101b in liver fibrosis.

    PubMed

    Yu, Fujun; Lu, Zhongqiu; Cai, Jing; Huang, Kate; Chen, Bicheng; Li, Guojun; Dong, Peihong; Zheng, Jianjian

    2015-01-01

    Emerging evidence shows that Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays a pivotal role in cell proliferation, migration, and invasion in tumors. However, the biological role and underlying mechanism of MALAT1 in liver fibrosis remains undefined. In this study, up-regulation of MALAT1 was observed in fibrotic liver tissues and in activated hepatic stellate cells (HSCs). In addition, depletion of MALAT1 inhibited the activation of HSCs in vitro and attenuated collagen deposits in vivo. Our results demonstrated that MALAT1 expression is negatively correlated with microRNA-101b (miR-101b) expression. Furthermore, there was a negative feedback loop between the levels of MALAT1 and miR-101b. Luciferase reporter assay indicated that MALAT1 and RAS-related C3 botulinum substrate 1 (Rac1) are targets of miR-101b. We uncovered that MALAT1 regulates Rac1 expression through miR-101b as a competing endogenous RNA (ceRNA), thereby influencing the proliferation, cell cycle and activation of primary HSCs. Collectively, The ceRNA regulatory network may prompt a better understanding of liver fibrogenesis and contribute to a novel therapeutic strategy for liver fibrosis.

  8. Long non-coding RNA MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in colorectal cancer cells

    PubMed Central

    Xie, Lin-Ying; Huang, Yu-qi; Liu, Yan-Ping; Xiao, Li-Wei; Li, Sheng-Nan; Zhu, Hui-Fang; Li, Zu-Guo; Kan, Heping

    2016-01-01

    Our earlier findings indicate that the long non-coding RNA MALAT1 promotes colorectal cancer (CRC) cell proliferation, invasion and metastasis in vitro and in vivo by increasing expression of AKAP-9. In the present study, we investigated the molecular mechanism by which MALAT1 enhances AKAP9 expression in CRC SW480 cells. We found that MALAT1 interacts with both SRPK1 and SRSF1. MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation. Following MALAT1 knockdown, overexpression of SRPK1 was sufficient to restore SRSF1 phosphorylation and AKAP-9 expression to a level that promoted cell proliferation, invasion and migration in vitro. Conversely, SRPK1 knockdown after overexpression of MALAT1 in SW480 cells diminished SRSF1 phosphorylation and AKAP-9 expression and suppressed cell proliferation, invasion and migration in vitro. These findings suggest MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in CRC cells. These results reveal a novel molecular mechanism by which MALAT1 regulates AKAP-9 expression in CRC cells. PMID:26887056

  9. Tumor-suppressive function of long noncoding RNA MALAT1 in glioma cells by downregulation of MMP2 and inactivation of ERK/MAPK signaling.

    PubMed

    Han, Y; Wu, Z; Wu, T; Huang, Y; Cheng, Z; Li, X; Sun, T; Xie, X; Zhou, Y; Du, Z

    2016-03-03

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long noncoding RNA. It is associated with metastasis and is a favorable prognostic factor for lung cancer. Recent studies have shown that MALAT1 plays an important role in other malignancies. But, little is known about the role of MALAT1 in glioma. In this study, quantitative reverse transcription PCR (qRT-PCR) was used to demonstrate that the expression of MALAT1 was lower than that in normal brain tissues. Stable RNA interference-mediated knockdown of MALAT1 in human glioma cell lines (U87 and U251) significantly promoted the invasion and proliferation of the glioma cells by in vitro assays. Conversely, overexpression of MALAT1 caused significant reduction in cell proliferation and invasion in vitro, and tumorigenicity in both subcutaneous and intracranial human glioma xenograft models. Furthermore, MALAT1-mediated tumor suppression in glioma cells may be via reduction of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling activity and expression of matrix metalloproteinase 2 (MMP2). In conclusion, overall data demonstrated the tumor-suppressive role of MALAT1 in glioma by attenuating ERK/MAPK-mediated growth and MMP2-mediated invasiveness.

  10. miR-124 downregulation leads to breast cancer progression via LncRNA-MALAT1 regulation and CDK4/E2F1 signal activation

    PubMed Central

    Feng, Tongbao; Shao, Fang; Wu, Qiyong; Zhang, Xiaohang; Xu, Dongqin; Qian, Keqing; Xie, Yewen; Wang, Shizhong; Xu, Ning; Wang, Yong; Qi, Chunjian

    2016-01-01

    The long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been recently shown to be dysregulated in several cancers. However, the mechanisms underlying the role of MALAT1 in breast cancer remain unclear. Herein, we showed that MALAT1 was aberrantly increased in breast cancer tissues and cells. MALAT1-siRNA inhibited breast cancer cell proliferation and cell cycle progression in vitro and in vivo. Furthermore, MALAT1 acted as an endogenous potent regulator by directly binding to miR-124 and down-regulating miR-124 expression. In addition, MALAT1 reversed the inhibitory effect of miR-124 on breast cancer proliferation and was involved in the cyclin-dependent kinase 4 (CDK4) expression. Taken together, our data highlight the pivotal role of MALAT1 in breast cancer tumorigenesis. Moreover, the present study elucidated the MALAT1-miR-124-CDK4/E2F1 signaling pathway in breast cancer, which might provide a new approach for tackling breast cancer. PMID:26918449

  11. miR-124 downregulation leads to breast cancer progression via LncRNA-MALAT1 regulation and CDK4/E2F1 signal activation.

    PubMed

    Feng, Tongbao; Shao, Fang; Wu, Qiyong; Zhang, Xiaohang; Xu, Dongqin; Qian, Keqing; Xie, Yewen; Wang, Shizhong; Xu, Ning; Wang, Yong; Qi, Chunjian

    2016-03-29

    The long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been recently shown to be dysregulated in several cancers. However, the mechanisms underlying the role of MALAT1 in breast cancer remain unclear. Herein, we showed that MALAT1 was aberrantly increased in breast cancer tissues and cells. MALAT1-siRNA inhibited breast cancer cell proliferation and cell cycle progression in vitro and in vivo. Furthermore, MALAT1 acted as an endogenous potent regulator by directly binding to miR-124 and down-regulating miR-124 expression. In addition, MALAT1 reversed the inhibitory effect of miR-124 on breast cancer proliferation and was involved in the cyclin-dependent kinase 4 (CDK4) expression. Taken together, our data highlight the pivotal role of MALAT1 in breast cancer tumorigenesis. Moreover, the present study elucidated the MALAT1-miR-124-CDK4/E2F1 signaling pathway in breast cancer, which might provide a new approach for tackling breast cancer.

  12. Tumor-suppressive function of long noncoding RNA MALAT1 in glioma cells by downregulation of MMP2 and inactivation of ERK/MAPK signaling

    PubMed Central

    Han, Y; Wu, Z; Wu, T; Huang, Y; Cheng, Z; Li, X; Sun, T; Xie, X; Zhou, Y; Du, Z

    2016-01-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long noncoding RNA. It is associated with metastasis and is a favorable prognostic factor for lung cancer. Recent studies have shown that MALAT1 plays an important role in other malignancies. But, little is known about the role of MALAT1 in glioma. In this study, quantitative reverse transcription PCR (qRT-PCR) was used to demonstrate that the expression of MALAT1 was lower than that in normal brain tissues. Stable RNA interference-mediated knockdown of MALAT1 in human glioma cell lines (U87 and U251) significantly promoted the invasion and proliferation of the glioma cells by in vitro assays. Conversely, overexpression of MALAT1 caused significant reduction in cell proliferation and invasion in vitro, and tumorigenicity in both subcutaneous and intracranial human glioma xenograft models. Furthermore, MALAT1-mediated tumor suppression in glioma cells may be via reduction of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling activity and expression of matrix metalloproteinase 2 (MMP2). In conclusion, overall data demonstrated the tumor-suppressive role of MALAT1 in glioma by attenuating ERK/MAPK-mediated growth and MMP2-mediated invasiveness. PMID:26938295

  13. Evaluation of 90-day Repeated Dose Oral Toxicity, Glycometabolism, Learning and Memory Ability, and Related Enzyme of Chromium Malate Supplementation in Sprague-Dawley Rats.

    PubMed

    Feng, Weiwei; Wu, Huiyu; Li, Qian; Zhou, Zhaoxiang; Chen, Yao; Zhao, Ting; Feng, Yun; Mao, Guanghua; Li, Fang; Yang, Liuqing; Wu, Xiangyang

    2015-11-01

    Our previous study showed that chromium malate improved the regulation of blood glucose in mice with alloxan-induced diabetes. The present study was designed to evaluate the 90-day oral toxicity of chromium malate in Sprague-Dawley rats. The present study inspected the effect of chromium malate on glycometabolism, glycometabolism-related enzymes, lipid metabolism, and learning and memory ability in metabolically healthy Sprague-Dawley rats. The results showed that all rats survived and pathological, toxic, feces, and urine changes were not observed. Chromium malate did not cause measurable damage on liver, brain, and kidney. The fasting blood glucose, serum insulin, insulin resistance index, C-peptide, hepatic glycogen, glucose-6-phosphate dehydrogenase, glucokinase, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels of normal rats in chromium malate groups had no significant change when compared with control group and chromium picolinate group under physiologically relevant conditions. The serum and organ content of Cr in chromium malate groups had no significant change compared with control group. No significant changes were found in morris water maze test and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and true choline esterase (TChE) activity. The results indicated that supplementation with chromium malate did not cause measurable toxicity and has no obvious effect on glycometabolism and related enzymes, learning and memory ability, and related enzymes and lipid metabolism of female and male rats. The results of this study suggest that chromium malate is safe for human consumption.

  14. Visnagin protects against doxorubicin-induced cardiomyopathy through modulation of mitochondrial malate dehydrogenase

    PubMed Central

    Liu, Yan; Asnani, Aarti; Zou, Lin; Bentley, Victoria L.; Yu, Min; Wang, You; Dellaire, Graham; Sarkar, Kumar S.; Dai, Matthew; Chen, Howard H.; Sosnovik, David E.; Shin, Jordan T.; Haber, Daniel A.; Berman, Jason N.; Chao, Wei; Peterson, Randall T.

    2015-01-01

    Doxorubicin is a highly effective anti-cancer chemotherapy agent, but its usage is limited by its cardiotoxicity. To develop a drug that prevents the cardiac toxicity of doxorubicin while preserving its anti-tumor potency, we established a doxorubicin-induced cardiomyopathy model in zebrafish that recapitulated the cardiomyocyte apoptosis and contractility decline observed in patients. Using this model, we screened 3000 compounds and discovered that visnagin (VIS) and diphenylurea (DPU) rescue cardiac performance and circulatory defects caused by doxorubicin treatment in zebrafish. VIS and DPU reduced doxorubicin-induced apoptosis in cultured cardiomyocytes and in vivo in zebrafish and mouse hearts. Furthermore, VIS treatment improved cardiac contractility in doxorubicin-treated mice. Importantly, VIS and DPU caused no reduction in the chemotherapeutic efficacy of doxorubicin in several cultured tumor lines or in zebrafish and mouse xenograft models. Using affinity chromatography, we discovered that VIS binds to mitochondrial malate dehydrogenase (MDH2), one of the key enzymes in the tricarboxylic acid cycle. As with VIS, treatment with the MDH2 inhibitors mebendazole, thyroxine, and iodine prevented doxorubicin cardiotoxicity, as did treatment with malate itself, suggesting that modulation of MDH2 activity is responsible for VIS’s cardioprotective effects. Taken together, this study identified VIS and DPU as potent cardioprotective compounds and implicates MDH2 as a previously undescribed, druggable target for doxorubicin-induced cardiomyopathy. PMID:25504881

  15. Phosphorylation of glyoxysomal malate synthase from castor oil seed endosperm and cucumber cotyledon

    SciTech Connect

    Yang, Y.P; Randall, D.D. )

    1989-04-01

    Glyoxysomal malate synthase (MS) was purified to apparent homogeneity from 3-d germinating castor oil seed endosperm by a relatively simple procedure including two sucrose density gradient centrifugations. Antibodies raised to the caster oil seed MS crossreacted with MS from cucumber cotyledon. MS was phosphorylated in both tissues in an MgATP dependent reaction. The phosphorylation pattern was similar for both enzymes and both enzymes were inhibited by NaF, NaMo, (NH{sub 4})SO{sub 4}, glyoxylate and high concentration of MgCl{sub 2} (60 mM), but was not inhibited by NaCl and malate. Further characterization of the phosphorylation of MS from castor oil seed endosperms showed that the 5S form of MS is the form which is labelled by {sup 32}P. The addition of exogenous alkaline phosphatase to MS not only decreased enzyme activity, but could also dephosphorylate phospho-MS. The relationship between dephosphorylation of MS and the decrease of MS activity is currently under investigation.

  16. Structural insights into the stabilization of MALAT1 noncoding RNA by a bipartite triple helix.

    PubMed

    Brown, Jessica A; Bulkley, David; Wang, Jimin; Valenstein, Max L; Yario, Therese A; Steitz, Thomas A; Steitz, Joan A

    2014-07-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a highly abundant nuclear long noncoding RNA that promotes malignancy. A 3'-stem-loop structure is predicted to confer stability by engaging a downstream A-rich tract in a triple helix, similar to the expression and nuclear retention element (ENE) from the KSHV polyadenylated nuclear RNA. The 3.1-Å-resolution crystal structure of the human MALAT1 ENE and A-rich tract reveals a bipartite triple helix containing stacks of five and four U•A-U triples separated by a C+•G-C triplet and C-G doublet, extended by two A-minor interactions. In vivo decay assays indicate that this blunt-ended triple helix, with the 3' nucleotide in a U•A-U triple, inhibits rapid nuclear RNA decay. Interruption of the triple helix by the C-G doublet induces a 'helical reset' that explains why triple-helical stacks longer than six do not occur in nature.

  17. Enzymatic Activity Analysis and Catalytic Essential Residues Identification of Brucella abortus Malate Dehydrogenase

    PubMed Central

    Han, Xiangan; Tong, Yongliang; Tian, Mingxing; Zhang, Yuxi; Sun, Xiaoqing; Wang, Shaohui; Qiu, Xusheng; Ding, Chan; Yu, Shengqing

    2014-01-01

    Malate dehydrogenase (MDH) plays important metabolic roles in bacteria. In this study, the recombinant MDH protein (His-MDH) of Brucella abortus was purified and its ability to catalyze the conversion of oxaloacetate (OAA) to L-malate (hereon referred to as MDH activity) was analyzed. Michaelis Constant (Km) and Maximum Reaction Velocity (Vmax) of the reaction were determined to be 6.45 × 10−3 M and 0.87 mM L−1 min−1, respectively. In vitro studies showed that His-MDH exhibited maximal MDH activity in pH 6.0 reaction buffer at 40°C. The enzymatic activity was 100%, 60%, and 40% inhibited by Cu2+, Zn2+, and Pb2+, respectively. In addition, six amino acids in the MDH were mutated to investigate their roles in the enzymatic activity. The results showed that the substitutions of amino acids Arg 89, Asp 149, Arg 152, His 176, or Thr 231 almost abolished the activity of His-MDH. The present study will help to understand MDH's roles in B. abortus metabolism. PMID:24895685

  18. A cysteine endopeptidase isolated from castor bean endosperm microbodies processes the glyoxysomal malate dehydrogenase precursor protein.

    PubMed

    Gietl, C; Wimmer, B; Adamec, J; Kalousek, F

    1997-03-01

    A plant cysteine endopeptidase with a molecular mass of 35 kD was purified from microbodies of germinating castor bean (Ricinus communis) endosperm by virtue of its capacity to specifically process the glyoxysomal malate dehydrogenase precursor protein to the mature subunit in vitro. Processing of the glyoxysomal malate dehydrogenase precursor occurs sequentially in three steps, the first intermediate resulting from cleavage after arginine-13 within the presequence and the second from cleavage after arginine-33. The endopeptidase is unable to remove the presequences of prethiolases from rape (Brassica napus) glyoxysomes and rat peroxisomes at the expected cleavage site. Protein sequence analysis of N-terminal and internal peptides revealed high identity to the mature papain-type cysteine endopeptidases from cotyledons of germinating mung bean (Vigna mungo) and French bean (Phaseolus vulgaris) seeds. These endopeptidases are synthesized with an extended pre-/prosequence at the N terminus and have been considered to be processed in the endoplasmic reticulum and targeted to protein-storing vacuoles.

  19. Oxidation of pyruvate, malate, citrate, and cytosolic reducing equivalents by AS-30D hepatoma mitochondria.

    PubMed

    Dietzen, D J; Davis, E J

    1993-08-15

    Mitochondria isolated from normal rat liver and AS-30D hepatoma were concurrently evaluated with regard to their bioenergetic and metabolic properties. AS-30D mitochondria oxidized many NAD-linked respiratory substrates at rates 1.5-4 times faster than those from liver, a fact which contributes to their diminished membrane depolarization on conversion from state 4 to state 3 respiration. AS-30D mitochondria exhibited no signs of a "truncated" Krebs cycle, nor did they oxidize malate preferentially based upon its origin in the cytosol or the mitochondrial matrix. In addition, beta-oxidation in AS-30D mitochondria was not sufficient to suppress respiratory CO2 production and induce pyruvate carboxylation to the extent observed in liver. Finally, AS-30D mitochondria were able to oxidize externally generated NADH in a reconstituted system, but in a manner independent of the transmembrane electrical potential (delta psi), suggesting that the malate-aspartate shuttle is not operable in vivo. This fact may necessitate the adaptations tumor cells make to reoxidize cytosolic NADH through glycolysis even in the presence of adequate oxygen. PMID:8342959

  20. Macromolecular crowding and the steady-state kinetics of malate dehydrogenase.

    PubMed

    Poggi, Christopher G; Slade, Kristin M

    2015-01-20

    To understand how macromolecular crowding affects enzyme activity, we quantified the Michaelis-Menten kinetics of mitochondrial malate dehydrogenase (MDH) in the presence of hen egg white (HEW), lysozyme, bovine serum albumin (BSA), gum arabic, poly(vinylpyrrolidone) (PVP), and dextrans of various molecular weights. Although crowding tended to decrease Km and Vmax values, the magnitude depended on the crowding agent, reaction direction, and isozyme (mitochondrial porcine heart or thermophlic TaqMDH from Thermus flavus). Crowding slowed oxaloacetate reduction more significantly than malate oxidation, which may suggest that mitochondrial enzymes have evolved to function optimally under the crowded constraints in which they are immersed. Since direct comparisons of neutral to charged crowders are underrepresented in the literature, we performed these studies and found that neutral crowding agents lowered Vmax values more than charged crowders of similar size. The exception was hen egg white, a mixture of charged proteins that caused the largest observed decreases in both Km and Vmax. Finally, the data provide insight about the mechanism by corroborating MDH subunit dependence.

  1. Clinical value of lncRNA MALAT1 as a prognostic marker in human cancer: systematic review and meta-analysis

    PubMed Central

    Tian, Xiaoling; Xu, Guoxiong

    2015-01-01

    Background Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is found to be overexpressed and associated with clinicopathological features in patients with cancer. Objectives To evaluate the clinical value of MALAT1 as a prognostic marker in human cancers by a comprehensive meta-analysis of published studies. Data sources The data on the prognostic impact of MALAT1 in cancer were collected from 11 September 2003 to 10 July 2015. Setting and participants Fourteen eligible studies with a total of 1373 patients conducted in 3 countries (9 in China, 3 in Japan and 2 in Germany) were matched to our inclusion criteria. Outcome measures Pooled HRs with 95% CIs were calculated to estimate the strength of the link between MALAT1 and clinical prognoses. The combined HRs heterogeneity was tested using a χ2-based Cochran Q test and Higgins I2 statistic. Publication bias was evaluated using a funnel plot with Egger's bias indicator test. Results A significant association between MALAT1 overexpression and poor overall survival (OS) (HR=1.95; 95% CI 1.57 to 2.41) was observed. Residence region (Germany and China), cancer type (respiratory, digestive or other system disease), sample size and paper quality did not alter the predictive value of MALAT1 on OS in investigated cancers. MALAT1 expression was an independent prognostic marker for OS in patients with cancer using univariate and multivariate analyses. Subgroup analysis showed that the elevated MALAT1 appeared to be a powerful prognostic marker for patients with respiratory, digestive and other system cancers. A similar effect was also seen in different regions. Furthermore, the overexpression of MALAT1 was associated with disease-free, recurrence-free and progression-free survivals. Conclusions MALAT1 may potentially be used as a new prognostic marker to predict poorer survival of patients with cancer. More clinical studies on the different types of human cancer not yet investigated need to be conducted. PMID

  2. Upregulation of long non-coding RNA MALAT1 correlates with tumor progression and poor prognosis in clear cell renal cell carcinoma.

    PubMed

    Zhang, Hai-min; Yang, Feng-qiang; Chen, Shao-Jun; Che, Jianping; Zheng, Jun-hua

    2015-04-01

    Long noncoding RNAs (lncRNAs) have been investigated as a new class of regulators of cellular processes, such as cell growth, apoptosis, and carcinogenesis. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has recently been identified to be involved in tumorigenesis of several cancers such as lung cancer, pancreatic cancer, and cervical cancer. However, the role of lncRNA MALAT1 in clear cell renal cell carcinoma (ccRCC) remains unclear. Expression levels of lncRNA MALAT1 in ccRCC tissues and renal cancer cell lines were evaluated by quantitative real-time PCR (qRT-PCR), and its association with overall survival of patients was analyzed by statistical analysis. Small interfering RNA (siRNA) was used to suppress MALAT1 expression in renal cancer cells. In vitro assays were conducted to further explore its role in tumor progression. The expression level of MALAT1 was higher in ccRCC tissues and renal cancer cells compared to adjacent non-tumor tissues and normal human proximal tubule epithelial cells HK-2. The ccRCC patients with higher MALAT1 expression had an advanced clinical features and a shorter overall survival time than those with lower MALAT1 expression. And multivariate analysis showed that the status of MALAT1 expression was an independent predictor of overall survival in ccRCC. Additionally, our data indicated that knockdown expression of MALAT1 decreased renal cancer cell proliferation, migration, and invasion. Our data suggested that lncRNA MALAT1 was a novel molecule involved in ccRCC progression, which provided a potential prognostic biomarker and therapeutic target.

  3. MALAT1-miR-124-RBG2 axis is involved in growth and invasion of HR-HPV-positive cervical cancer cells.

    PubMed

    Liu, Shikai; Song, Lili; Zeng, Saitian; Zhang, Liang

    2016-01-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT 1) is a large, infrequently spliced non-coding RNA aberrantly expressed in cervical cancer. But the molecular mechanisms of its oncogenic role are still not quite clear. The present study explored whether there is a competing endogenous RNAs (ceRNAs) mechanism involved in the oncogenic effect of MALAT1. MALAT1 expression was firstly verified in high-risk human papillomavirus (HR-HPV)-positive tumor tissues and cell lines. Its regulation over miR-124 and the downstream target of miR-124 in regulation of growth, invasion, and apoptosis of the cancer cells are also studied. Findings of this study confirmed higher MALAT1 expression in HR-HPV (+) cervical cancer. Knockdown of endogenous MALAT1 significantly reduced cell growth rate and invasion and increased cell apoptosis of Hela and siHa cells. Besides, knockdown of MALAT1 increased the expression of miRNA-124, while ectopic expression of miR-124 decreased MALAT1 expression. In addition, we also verified a direct interaction between miR-124 and 3'UTR of GRB2. MALAT1 can indirectly modulate GRB2 expression via competing miR-124. Knockdown of GRB2 reduced cell invasion and increased cell apoptosis. In conclusion, MALAT1 can promote HR-HPV (+) cancer cell growth and invasion at least partially through the MALAT1-miR-124-RBG2 axis. This finding might provide some useful evidence about the lncRNA interaction regulatory network in tumorigenesis cervical cancer.

  4. The HIF-2α-MALAT1-miR-216b axis regulates multi-drug resistance of hepatocellular carcinoma cells via modulating autophagy.

    PubMed

    Yuan, Peng; Cao, Weibin; Zang, Quanling; Li, Guixin; Guo, Xiangfei; Fan, Jianghe

    2016-09-23

    In this study, we firstly investigated the association among lncRNA MALAT1, HIF-1α and HIF-2α in hepatocellular carcinoma (HCC) cells. Then, we investigated the regulative effect of MALAT1 on multi-drug resistance (MDR) in HCC cells and the underlying mechanism. The results showed that MALAT1 was over two times higher in BEL-7402/5-FU cells than in BEL-7402 cells. It was HIF-2α, but not HIF-1α induced MALAT1 upregulation in HCC cells. Dual luciferase assay demonstrated that there were at least two binding sites of miR-26b in MALAT1. Therefore, we infer that there is a HIF-2α-MALAT1-miR-216b axis in HCC cells. Cell viability assay showed that both MALAT1 siRNA and miR-216b mimics reduced IC50 of 5-FU, ADR and MMC in BEL-7402/5-FU cells. MALAT1 siRNA and miR-216b mimics showed similar effect as 3-MA on reducing LC3-II levels, inhibiting p62 degradation and suppressing GFP-LC3 puncta formation in BEL-7402/5-FU cells. Flow cytometric analysis showed that 3-MA treatment, MALAT1 siRNA and miR-216b mimics all promoted 5-FU induced apoptosis in BEL-7402/5-FU cells. Therefore, this study firstly revealed that there is a HIF-2α-MALAT1-miR-216b axis regulating MDR of HCC cells via modulating autophagy. PMID:27524242

  5. Red clover HCT2, a hydroxycinnamoyl-coenzyme A:malate hydroxycinnamoyl transferase, plays a crucial role in biosynthesis of phaselic acid and other hydroxycinnamoyl-malate esters in vivo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In red clover (Trifolium pratense) leaves, phaselic acid (2-O-caffeoyl-L-malate) accumulates to several mmol kg-1 fresh weight and is a crucial component of a natural system that prevents protein breakdown during harvest and storage of this forage crop. Previously, we identified HCT2, a red clover g...

  6. Nanomolar aluminum induces expression of the inflammatory systemic biomarker C-reactive protein (CRP) in human brain microvessel endothelial cells (hBMECs).

    PubMed

    Alexandrov, Peter N; Kruck, Theodore P A; Lukiw, Walter J

    2015-11-01

    C-reactive protein (CRP; also known as pentraxin 1, PTX1), a 224 amino acid soluble serum protein organized into a novel pentameric ring-shaped structure, is a highly sensitive pathogenic biomarker for systemic inflammation. High CRP levels are found in practically every known inflammatory state, and elevated CRP levels indicate an increased risk for several common age-related human degenerative disorders, including cardiovascular disease, cancer, diabetes, and Alzheimer's disease (AD). While the majority of CRP is synthesized in the liver for secretion into the systemic circulation, it has recently been discovered that an appreciable amount of CRP is synthesized in highly specialized endothelial cells that line the vasculature of the brain and central nervous system (CNS). These highly specialized cells, the major cell type lining the human CNS vasculature, are known as human brain microvessel endothelial cells (hBMECs). In the current pilot study we examined (i) CRP levels in human serum obtained from AD and age-matched control patients; and (ii) analyzed the effects of nanomolar aluminum sulfate on CRP expression in primary hBMECs. The three major findings in this short communication are: (i) that CRP is up-regulated in AD serum; (ii) that CRP serum levels increased in parallel with AD progression; and (iii) for the first time show that nanomolar aluminum potently up-regulates CRP expression in hBMECs to many times its 'basal abundance'. The results suggest that aluminum-induced CRP may in part contribute to a pathophysiological state associated with a chronic systemic inflammation of the human vasculature.

  7. Analysis of Quaternary Structure of a [LDH-like] Malate Dehydrogenase of Plasmodium falciparum with Oligomeric Mutants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    L-Malate dehydrogenase (PfMDH) from Plasmodium falciparum, the causative agent for the most severe form of malaria, has shown remarkable similarities to L-lactate dehydrogenase (PfLDH). PfMDH is more closely related to [LDH-like] MDHs characterized in archea and other prokaryotes. Initial sequence a...

  8. SIRT3-dependent GOT2 acetylation status affects the malate-aspartate NADH shuttle activity and pancreatic tumor growth.

    PubMed

    Yang, Hui; Zhou, Lisha; Shi, Qian; Zhao, Yuzheng; Lin, Huaipeng; Zhang, Mengli; Zhao, Shimin; Yang, Yi; Ling, Zhi-Qiang; Guan, Kun-Liang; Xiong, Yue; Ye, Dan

    2015-04-15

    The malate-aspartate shuttle is indispensable for the net transfer of cytosolic NADH into mitochondria to maintain a high rate of glycolysis and to support rapid tumor cell growth. The malate-aspartate shuttle is operated by two pairs of enzymes that localize to the mitochondria and cytoplasm, glutamate oxaloacetate transaminases (GOT), and malate dehydrogenases (MDH). Here, we show that mitochondrial GOT2 is acetylated and that deacetylation depends on mitochondrial SIRT3. We have identified that acetylation occurs at three lysine residues, K159, K185, and K404 (3K), and enhances the association between GOT2 and MDH2. The GOT2 acetylation at these three residues promotes the net transfer of cytosolic NADH into mitochondria and changes the mitochondrial NADH/NAD(+) redox state to support ATP production. Additionally, GOT2 3K acetylation stimulates NADPH production to suppress ROS and to protect cells from oxidative damage. Moreover, GOT2 3K acetylation promotes pancreatic cell proliferation and tumor growth in vivo. Finally, we show that GOT2 K159 acetylation is increased in human pancreatic tumors, which correlates with reduced SIRT3 expression. Our study uncovers a previously unknown mechanism by which GOT2 acetylation stimulates the malate-aspartate NADH shuttle activity and oxidative protection. PMID:25755250

  9. Structure and Function of Plasmodium falciparum malate dehydrogenase: Role of Critical Amino Acids in C-substrate Binding Procket

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malaria parasite thrives on anaerobic fermentation of glucose for energy. Earlier studies from our lab have demonstrated that a cytosolic malate dehydrogenase (PfMDH) with striking similarity to lactate dehydrogenase (PfLDH) might complement PfLDH function in Plasmodium falciparum. The N-terminal g...

  10. Aluminum-activated citrate and malate transporters from the MATE and ALMT families function independently to confer Arabidopsis aluminum tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) activated root malate and citrate exudation plays an important role in Al tolerance in many plant species. Here, we report on the identification and characterization of AtMATE, a homolog of the recently discovered sorghum and barley Al tolerance genes, here shown to encode an Al-activ...

  11. Resveratrol inhibits invasion and metastasis of colorectal cancer cells via MALAT1 mediated Wnt/β-catenin signal pathway.

    PubMed

    Ji, Qing; Liu, Xuan; Fu, Xiaoling; Zhang, Long; Sui, Hua; Zhou, Lihong; Sun, Jian; Cai, Jianfeng; Qin, Jianmin; Ren, Jianlin; Li, Qi

    2013-01-01

    Resveratrol, extracted from Chinese herbal medicine Polygonum cuspidatum, is known to inhibit invasion and metastasis of human colorectal cancer (CRC), in which long non-coding Metastasis Associated Lung Adenocarcinoma Transcript 1 (RNA-MALAT1) also plays an important role. Using MALAT1 lentiviral shRNA and over-expression constructs in CRC derived cell lines, LoVo and HCT116, we demonstrated that the anti-tumor effects of resveratrol on CRC are through inhibiting Wnt/β-catenin signaling, thus the expression of its target genes such as c-Myc, MMP-7, as well as the expression of MALAT1. In detail, resveratrol down-regulates MALAT1, resulting in decreased nuclear localization of β-catenin thus attenuated Wnt/β-catenin signaling, which leads to the inhibition of CRC invasion and metastasis. This finding of ours surely provides important pre-clinical evidence supporting future use of resveratrol in prevention and treatment of CRC. PMID:24244343

  12. Effect of some anthelmintics on malate dehydrogenase activity and mortality in two avian nematodes Ascaridia galli and Heterakis gallinae.

    PubMed

    Sharma, R K; Singh, K; Saxena, R; Saxena, K K

    1986-08-01

    Cambendazole and tiabendazole at 10(-4) M concentrations caused mortality in both the parasites after 10 min and 20 min, respectively. H. gallinae was killed by 10(-4) M haloxon but A. galli remained alive even after 60 min exposure. The effect of these drugs was found to be irreversible since no resumption of activity was observed when the parasites were returned to normal saline solution. The ratio of oxaloacetate reduction to malate oxidation in the homogenates of A. galli and H. gallinae was 4.38:1 and 3.17:1 respectively. Cambendazole at 10(-3) M inhibited the enzymic activity in both directions by 100% in both A. galli and H. gallinae. 10(-3) M tiabendazole, however, inhibited the malate oxidation by 82.8 and 60.8% and oxaloacetate reduction by 76.6 and 92% in A. galli and H. gallinae, respectively. Haloxon had little effect on malate dehydrogenase activity of any of the parasite. Assay of malate dehydrogenase, following the in vitro drug treatment cambendazole and tiabendazole, exhibited moderate inhibition of the activity in both the parasites.

  13. Correlation of increased MALAT1 expression with pathological features and prognosis in cancer patients: a meta-analysis.

    PubMed

    Shi, X S; Li, J; Yang, R H; Zhao, G R; Zhou, H P; Zeng, W X; Zhou, M

    2015-12-29

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been identified as a potential cancer biomarker, yet the mechanism by which it influences the development of cancer remains unknown. In this study, we aimed to correlate MALAT1 expression with pathological features and prognosis in cancer patients. Several databases were searched using combinations of keywords relating to MALAT1 and cancer. After selection of relevant cohort studies according to strict criteria, a meta-analysis was conducted. Twelve studies were analyzed, involving 958 cancer patients. Elevated MALAT1 expression was associated with poor prognosis and larger tumors [prognosis: hazard ratio = 3.11, 95% confidence interval (CI) = 1.98-4.23, P = 0.000; tumor size: odds ratio (OR) = 0.40, 95%CI = 0.21-0.74, P = 0.003]. However, no connection with histological grade, T-stage, lymph node (LN) metastasis, or distant metastasis was established (all P > 0.05). A correlation between increased expression and poor prognosis was observed in the large and small sample-size subgroups (all P< 0.05), as was a relationship with large tumor size (OR = 0.30, 95%CI = 0.13-0.71, P = 0.006). Expression was correlated with T-stage and distant metastasis in the small sample-size subgroup (all P < 0.05), but no association was detected regarding histological grade, LN metastasis in either subgroup (all P > 0.05). Our findings demonstrate that elevated MALAT1 expression correlates with large tumor size, advanced tumor stage, and poor prognosis, and might therefore be utilized to evaluate clinical pathological features and prognostic out come for cancer patients.

  14. Potential roles of abnormally expressed long noncoding RNA UCA1 and Malat-1 in metastasis of melanoma.

    PubMed

    Tian, Yongjing; Zhang, Xiuying; Hao, Yinghua; Fang, Zhengyu; He, Yanling

    2014-08-01

    Melanoma is a highly aggressive skin cancer with increasing incidence worldwide. Long noncoding RNAs (lncRNAs), a group of nonprotein-coding transcripts longer than 200 nucleotides, are pervasively transcribed in the genome and are emerging as new players in tumorigenesis. The primary objective of this study was to investigate the role of six cancer-related lncRNAs in pairs of melanoma and adjacent normal tissues (ANTs). A total of 63 primary melanoma, paired ANTs, and metastatic lesions were collected in a Chinese population. Real-time PCR analysis was carried out to compare a series of cancer-related lncRNAs among primary melanoma tissues, ANTs, and metastatic lesions. In in-vitro studies, transwell migration assay was carried out to estimate the migration abilities of melanoma cells with different expression levels of urothelial carcinoma-associated 1 (UCA1) or metastasis-associated lung adenocarcinoma transcript 1 (Malat-1) lncRNAs. We found that UCA1 and Malat-1 lncRNAs were markedly more increased in melanomas than in paired ANTs (P<0.05). Melanomas at later stages (stages 3-4) showed higher expression of UCA1 lncRNA than those at early stages (stages 1-2) (P=0.455). In melanomas with lymph node metastasis, the metastatic lesions had a relatively higher expression of Malat-1 lncRNA than in paired primary tumors (P=0.414). Knockdown of UCA1 or Malat-1 lncRNA could attenuate the migrational ability of melanoma cells in in-vitro studies. Increased expression of UCA1 and Malat-1 lncRNAs might have a correlation with melanoma metastasis.

  15. The vacuolar channel VvALMT9 mediates malate and tartrate accumulation in berries of Vitis vinifera.

    PubMed

    De Angeli, Alexis; Baetz, Ulrike; Francisco, Rita; Zhang, Jingbo; Chaves, Maria Manuela; Regalado, Ana

    2013-08-01

    Vitis vinifera L. represents an economically important fruit species. Grape and wine flavour is made from a complex set of compounds. The acidity of berries is a major parameter in determining grape berry quality for wine making and fruit consumption. Despite the importance of malic and tartaric acid (TA) storage and transport for grape berry acidity, no vacuolar transporter for malate or tartrate has been identified so far. Some members of the aluminium-activated malate transporter (ALMT) anion channel family from Arabidopsis thaliana have been shown to be involved in mediating malate fluxes across the tonoplast. Therefore, we hypothesised that a homologue of these channels could have a similar role in V. vinifera grape berries. We identified homologues of the Arabidopsis vacuolar anion channel AtALMT9 through a TBLASTX search on the V. vinifera genome database. We cloned the closest homologue of AtALMT9 from grape berry cDNA and designated it VvALMT9. The expression profile revealed that VvALMT9 is constitutively expressed in berry mesocarp tissue and that its transcription level increases during fruit maturation. Moreover, we found that VvALMT9 is targeted to the vacuolar membrane. Using patch-clamp analysis, we could show that, besides malate, VvALMT9 mediates tartrate currents which are higher than in its Arabidopsis homologue. In summary, in the present study we provide evidence that VvALMT9 is a vacuolar malate channel expressed in grape berries. Interestingly, in V. vinifera, a tartrate-producing plant, the permeability of the channel is apparently adjusted to TA.

  16. 17β-Estradiol treatment inhibits breast cell proliferation, migration and invasion by decreasing MALAT-1 RNA level

    SciTech Connect

    Zhao, Ziyi; Chen, Changjin; Liu, Yu; Wu, Chuanfang

    2014-03-07

    Highlights: • E2 affects not only estrogen-receptor α positive breast cells but also negative ones. • 100 nM E2 treatment affects breast cells proliferation, migration. • 100 nM E2 treatment functions in an estrogen-receptor α-independent way. • E2 treatment decreases MALAT-1 RNA level by post-transcriptional regulation. - Abstract: Breast cancer cells, which express estrogen receptor α (ERα), respond to estrogen in a concentration dependent fashion, resulting in proliferation or apoptosis. But breast cancer cells without ERα show no effect on low concentration of estrogen treatment. Proliferation, migration and invasion of MCF10a, MCF7 and MB231 cells treated with low (1 nM) or high (100 nM) dose of 17β-Estradiol (E2) was performed. We identified the effects of E2 on these breast cell lines, and looked for the difference in the presence and absence of ERα. Specifically, we looked for the changes of long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT-1), which is found extensively and highly expressed in several kinds of tumor cells, including breast carcinoma. It was observed that proliferation, migration and invasion of breast cells were greatly affected by high concentration E2 treatment and were not affected by low concentration E2 treatment in an ERα independent way. We found that the high concentration E2 treatment largely decreased MALAT-1 RNA level. Interestingly, MALAT-1 decreasing by knocking down showed similar effects on proliferation, migration and invasion. E2 treatment affects breast tumor or non-tumor cells proliferation, migration and invasion in an ERα -independent, but a dose-dependent way by decreasing the MALAT-1 RNA level.

  17. L-Malate dehydrogenase activity in the reductive arm of the incomplete citric acid cycle of Nitrosomonas europaea.

    PubMed

    Deutch, Charles E

    2013-11-01

    The autotrophic nitrifying bacterium Nitrosomonas europaea does not synthesize 2-oxoglutarate (α-ketoglutarate) dehydrogenase under aerobic conditions and so has an incomplete citric acid cycle. L-malate (S-malate) dehydrogenase (MDH) from N. europaea was predicted to show similarity to the NADP(+)-dependent enzymes from chloroplasts and was separated from the NAD(+)-dependent proteins from most other bacteria or mitochondria. MDH activity in a soluble fraction from N. europaea ATCC 19718 was measured spectrophotometrically and exhibited simple Michaelis-Menten kinetics. In the reductive direction, activity with NADH increased from pH 6.0 to 8.5 but activity with NADPH was consistently lower and decreased with pH. At pH 7.0, the K m for oxaloacetate was 20 μM; the K m for NADH was 22 μM but that for NADPH was at least 10 times higher. In the oxidative direction, activity with NAD(+) increased with pH but there was very little activity with NADP(+). At pH 7.0, the K m for L-malate was 5 mM and the K m for NAD(+) was 24 μM. The reductive activity was quite insensitive to inhibition by L-malate but the oxidative activity was very sensitive to oxaloacetate. MDH activity was not strongly activated or inhibited by glycolytic or citric acid cycle metabolites, adenine nucleotides, NaCl concentrations, or most metal ions, but increased with temperature up to about 55 °C. The reductive activity was consistently 10-20 times higher than the oxidative activity. These results indicate that the L-malate dehydrogenase in N. europaea is similar to other NAD(+)-dependent MDHs (EC 1.1.1.37) but physiologically adapted for its role in a reductive biosynthetic sequence.

  18. Plastidial NAD-Dependent Malate Dehydrogenase Is Critical for Embryo Development and Heterotrophic Metabolism in Arabidopsis1[W][OPEN

    PubMed Central

    Beeler, Seraina; Liu, Hung-Chi; Stadler, Martha; Schreier, Tina; Eicke, Simona; Lue, Wei-Ling; Truernit, Elisabeth; Zeeman, Samuel C.; Chen, Jychian; Kötting, Oliver

    2014-01-01

    In illuminated chloroplasts, one mechanism involved in reduction-oxidation (redox) homeostasis is the malate-oxaloacetate (OAA) shuttle. Excess electrons from photosynthetic electron transport in the form of nicotinamide adenine dinucleotide phosphate, reduced are used by NADP-dependent malate dehydrogenase (MDH) to reduce OAA to malate, thus regenerating the electron acceptor NADP. NADP-MDH is a strictly redox-regulated, light-activated enzyme that is inactive in the dark. In the dark or in nonphotosynthetic tissues, the malate-OAA shuttle was proposed to be mediated by the constitutively active plastidial NAD-specific MDH isoform (pdNAD-MDH), but evidence is scarce. Here, we reveal the critical role of pdNAD-MDH in Arabidopsis (Arabidopsis thaliana) plants. A pdnad-mdh null mutation is embryo lethal. Plants with reduced pdNAD-MDH levels by means of artificial microRNA (miR-mdh-1) are viable, but dark metabolism is altered as reflected by increased nighttime malate, starch, and glutathione levels and a reduced respiration rate. In addition, miR-mdh-1 plants exhibit strong pleiotropic effects, including dwarfism, reductions in chlorophyll levels, photosynthetic rate, and daytime carbohydrate levels, and disordered chloroplast ultrastructure, particularly in developing leaves, compared with the wild type. pdNAD-MDH deficiency in miR-mdh-1 can be functionally complemented by expression of a microRNA-insensitive pdNAD-MDH but not NADP-MDH, confirming distinct roles for NAD- and NADP-linked redox homeostasis. PMID:24453164

  19. Structure of Escherichia coli malate dehydrogenase at 1.45 Å resolution

    PubMed Central

    Zaitseva, Jelena; Meneely, Kathleen M.; Lamb, Audrey L.

    2009-01-01

    The structure of apo malate dehydrogenase from Escherichia coli has been determined to 1.45 Å resolution. The crystals belonged to space group C2, with unit-cell parameters a = 146.0, b = 52.0, c = 168.9 Å, β = 102.2°. The structure was determined with the molecular-replacement pipeline program BALBES and was refined to a final R factor of 18.6% (R free = 21.4%). The final model has two dimers in the asymmetric unit. In each dimer one monomer contains the active-site loop in the open conformation, whereas in the opposing monomer the active-site loop is disordered. PMID:19724119

  20. [Autonomic disorders in persons with asthenic syndrome and their correction with citrulline malate].

    PubMed

    Fedorova, V I

    2000-01-01

    The paper presents the results of the investigation of psychoautonomic correlations in 15 patients with psychogenic asthenia. Spilberg's and Beck's tests as well as autonomic questionnaire were used for the psychologic testing. Sympathic-parasympathic correlations were investigated by means of cardiovascular tests, by evoked skin sympathetic potentials, variability of cardiac rhythm under conditions of different functional states. The patients had mild anxious-depressive and pronounced autonomic disorders with prevalence of cerebral sympathic-adrenal impacts, elevation of vagal influences in cardiovascular system, mediatory insufficiency of the sympathic sweating nerves and a decrease of the adaptive abilities of the regulatory systems. To correct the asthenic manifestations citrullin malate (stimol), a metabolic corrector produced by "Laboratories BIOCODEX" (France) was used. Stimol relieves psychoautonomic disorders by increasing both power capacities of the cells and synthesis of biologically active substances. PMID:10812668

  1. Citrulline-malate effect on microsome phospholipids and cytochrome P450 in Euglena grown with ethanol.

    PubMed

    Thuillier-Bruston, F; Julistiono, H; Briand, J

    1991-04-01

    This study indicates for the first time the presence of cytochrome P450 in the microsomes of Euglena grown in lactate medium and substantiates the use of Euglena as a hepatic cell model. Similar effects of ethanol on Euglena and on rat hepatic microsomes were demonstrated: (i) decrements in the quantities of FA per milligram of proteins; (ii) increases in the proportions of PE; (iii) decreases in the proportions of PC; and (iv) production of cytochrome P450, degraded in P420. The citrulline-malate reestablishes in the microsomes the phospholipid environment and the cytochrome P450 concentration. These findings illustrate that the complex acts on the lipid peroxidation via the changes in cytochrome P450 activity. PMID:1909150

  2. MALAT1 long ncRNA promotes gastric cancer metastasis by suppressing PCDH10

    PubMed Central

    Qi, Ying; Ooi, Hong Sain; Wu, Jun; Chen, Jian; Zhang, Xiaoli; Tan, Sheng; Yu, Qing; Li, Yuan-Yuan; Kang, Yani; Li, Hua; Xiong, Zirui; Zhu, Tao; Liu, Bingya; Shao, Zhifeng; Zhao, Xiaodong

    2016-01-01

    EZH2, the catalytic component of polycomb repressive complex 2 (PRC2), is frequently overexpressed in human cancers and contributes to tumor initiation and progression, in part through transcriptional silencing of tumor suppressor genes. A number of noncoding RNAs (ncRNAs) recruit EZH2 to specific chromatin loci, where they modulate gene expression. Here, we used RNA immunoprecipitation sequencing (RIP-seq) to profile EZH2-associated transcripts in human gastric cancer cell lines. We identified 8,256 transcripts, including both noncoding and coding transcripts, some of which were derived from cancer-related loci. In particular, we found that long noncoding RNA (lncRNA) MALAT1 binds EZH2, suppresses the tumor suppressor PCDH10, and promotes gastric cellular migration and invasion. Our work thus provides a global view of the EZH2-associated transcriptome and offers new insight into the function of EZH2 in gastric tumorigenesis. PMID:26871474

  3. The lncRNA Malat1 is dispensable for mouse development but its transcription plays a cis-regulatory role in the adult

    PubMed Central

    Zhang, Bin; Arun, Gayatri; Mao, Yuntao S.; Lazar, Zsolt; Hung, Gene; Bhattacharjee, Gourab; Xiao, Xiaokun; Booth, Carmen J.; Wu, Jie; Zhang, Chaolin; Spector, David L.

    2012-01-01

    SUMMARY Genome-wide studies have identified thousands of long noncoding RNAs (lncRNAs) lacking protein coding capacity. However, most lncRNAs are expressed at a very low level, and in most cases there is no genetic evidence to support their in vivo function. Malat1 (metastasis associated lung adenocarcinoma transcript 1) is among the most abundant and highly conserved lncRNAs, and it exhibits an uncommon 3′-end processing mechanism. In addition, its specific nuclear localization, developmental regulation, and dysregulation in cancer are suggestive of it having a critical biological function. We have characterized a Malat1 loss-of-function genetic model that indicates Malat1 is not essential for mouse pre- and post-natal development. Furthermore, depletion of Malat1 does not impact global gene expression, splicing factor level and phosphorylation status, or alternative pre-mRNA splicing. However, among a small number of genes that were dysregulated in adult Malat1 knockout mice, many were Malat1 neighboring genes, thus indicating a potential cis regulatory role of Malat1 gene transcription. PMID:22840402

  4. Acute Citrulline-Malate Supplementation and High-Intensity Cycling Performance.

    PubMed

    Cunniffe, Brian; Papageorgiou, Maria; OʼBrien, Barbara; Davies, Nathan A; Grimble, George K; Cardinale, Marco

    2016-09-01

    Cunniffe, B, Papageorgiou, M, O'Brien, B, Davies, NA, Grimble, GK, and Cardinale, M. Acute citrulline-malate supplementation and high-intensity cycling performance. J Strength Cond Res 30(9): 2638-2647, 2016-Dietary L-citrulline-malate (CM) consumption has been suggested to improve skeletal muscle metabolism and contractile efficiency, which would be expected to predispose exercising individuals to greater fatigue resistance. The purpose of this study was to examine the effects of CM supplementation on acid-base balance and high-intensity exercise performance. In a double-blind, placebo-controlled, crossover study, 10 well-trained males consumed either 12 g of CM (in 400 ml) or lemon sugar-free cordial (placebo [PL]) 60 minutes before completion of 2 exercise trials. Each trial consisted of subjects performing 10 (×15 seconds) maximal cycle sprints (with 30-second rest intervals) followed by 5 minutes recovery before completing a cycle time-to-exhaustion test (TTE) at 100% of individual peak power (PP). Significant increases in plasma concentrations of citrulline (8.8-fold), ornithine (3.9-fold), and glutamine (1.3-fold) were observed 60 minutes after supplementation in the CM trial only (p ≤ 0.05) and none of the subjects experienced gastrointestinal side-effects during testing. Significantly higher exercise heart rates were observed in CM condition (vs. PL) although no between trial differences in performance related variables (TTE: [120 ± 61 seconds CM vs. 113 ± 50 seconds PL]), PP or mean power, ([power fatigue index: 36 ± 16% CM vs. 28 ± 18% PL]), subjective rating of perceived exertion or measures of acid-base balance (pH, lactate, bicarbonate, base-excess) were observed (p > 0.05). This study demonstrated that acute supplementation of 12 g CM does not provide acute ergogenic benefits using the protocol implemented in this study in well-trained males. PMID:26808848

  5. Primary structure of the light-dependent regulatory site of corn NADP-malate dehydrogenase

    SciTech Connect

    Decottignies, P.; Schmitter, J.M.; Miginiac-Maslow, M.; Le Marechal, P.; Jacquot, J.P.; Gadal, P.

    1988-08-25

    The light-activated NADP-malate dehydrogenase (NADP-MDH) catalyzes the reduction of oxaloacetate to malate in higher plant chloroplasts. This enzyme is regulated in vivo by the ferredoxin-thioredoxin system through redox reactions. NADP-MDH has been photoactivated in vitro in a chloroplast system reconstituted from the pure protein components and thylakoid membranes. Photoactivation was accompanied by the appearance of new thiol groups (followed by (14C)iodoacetate incorporation). 14C-Carboxymethylated NADP-MDH has been purified from the incubation mixture and its amino-terminal sequence analyzed. Two (14C)carboxymethylcysteines were identified at positions 10 and 15 after light activation, while they were not detected in the dark-treated protein. In addition, the analysis of the tryptic digest of light-activated (14C)carboxymethylated NADP-MDH revealed that the radioactive label was mostly incorporated in Cys10 and Cys15, indicating that these 2 residues play a major role in the light activation mechanism. Moreover, an activation model, in which photoreduced thio-redoxin was replaced by the dithiol reductant dithio-threitol, has been developed. When NADP-MDH was activated in this way, the same sulfhydryls were found to be labeled, and alternatively, they did not incorporate any radioactivity when dithiothreitol reduction was performed after carboxymethylation in denaturating conditions. These results indicate that activation (by light or by dithiothreitol) proceeds on each subunit by reduction of a disulfide bridge located at the amino terminus of the enzyme between Cys10 and Cys15.

  6. Hoogsteen-position pyrimidines promote the stability and function of the MALAT1 RNA triple helix.

    PubMed

    Brown, Jessica A; Kinzig, Charles G; DeGregorio, Suzanne J; Steitz, Joan A

    2016-05-01

    Triple-stranded RNA was first deduced to form in vitro more than 50 years ago and has since been implicated in RNA catalysis, stability, and small molecule binding. Despite the emerging biological significance of RNA triple helices, it remains unclear how their nucleotide composition contributes to their thermodynamic stability and cellular function. To investigate these properties, we used in vitro RNA electrophoretic mobility shift assays (EMSAs) and in vivo intronless β-globin reporter assays to measure the relative contribution of 20 RNA base triples (N•A-U, N•G-C, N•C-G, N•U-A, and N•G-U) to triple-helical stability. These triples replaced a single internal U•A-U within the known structure of the triple-helical RNA stability element of human metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), which contains 10 major-groove base triples. In addition to the canonical C•G-C triple, the noncanonical base triples U•G-C, U•G-U, C•C-G, and U•C-G exhibited at least 30% stability relative to the wild-type U•A-U base triple in both assays. Of these triples, only U•A-U, C•G-C, and U•G-C, when tested as four successive triples, formed stabilizing structures that allowed accumulation of the intronless β-globin reporter. Overall, we find that Hoogsteen-position pyrimidines support triple helix stability and function and that thermodynamic stability, based on EMSA results, is necessary but not sufficient for stabilization activity of the MALAT1 triple helix in cells. These results suggest that additional RNA triple helices containing noncanonical triples likely exist in nature.

  7. Evaluation of the Reproductive Toxicity, Glycometabolism, Glycometabolism-Related Enzyme Levels and Lipid Metabolism of Chromium Malate Supplementation in Sprague-Dawley Rats.

    PubMed

    Feng, Weiwei; Zhang, Weijie; Zhao, Ting; Mao, Guanghua; Wang, Wei; Wu, Xueshan; Zhou, Zhaoxiang; Huang, Jing; Bao, Yongtuan; Yang, Liuqing; Wu, Xiangyang

    2015-11-01

    Our previous study showed that chromium malate improved the regulation of blood glucose in mice with alloxan-induced diabetes. The present study was designed to evaluate the reproductive toxicity of chromium malate in Sprague-Dawley rats and then inspected the effect of chromium malate on glycometabolism, glycometabolism-related enzymes, and lipid metabolism. The results showed that no pathological, toxic feces and urine changes were observed in clinical signs of parental and fetal rats in chromium malate groups. The fasting blood glucose, serum insulin, insulin resistance index, C-peptide, hepatic glycogen, glucose-6-phosphate dehydrogenase, glucokinase, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels of chromium malate groups have no significant change compared with control group and chromium picolinate group. The serum and organ contents of Cr in chromium malate groups have no significant change when compared with control group. No measurable damage on liver, brain, kidney, and testis/uterus of chromium malate groups was found. No significant change in body mass, absolute and relative organ weights, and hematological and biochemical changes of rats were observed compared with the control and chromium picolinate groups. The results indicated that supplements with chromium malate does not cause obvious damage and has no obvious effect on glycometabolism, glycometabolism-related enzyme, and lipid metabolism on female and male rats. The results of this study suggested that chromium malate is safe for human consumption and has the potential for application as a functional food ingredient and dietary supplement. PMID:25876088

  8. A naked-eye sensing ensemble for the selective detection of citrate--but not tartrate or malate--in water based on a tris-cationic receptor.

    PubMed

    Schmuck, Carsten; Schwegmann, Michael

    2006-03-01

    Citrate 3 can be selectively detected in aqueous solvents even in the presence of malate or tartrate using a naked-eye detection system based on the complex between tris-cation 1 and carboxyfluorescein 2.

  9. Long non-coding RNA MALAT1 modulates radiosensitivity of HR-HPV+ cervical cancer via sponging miR-145.

    PubMed

    Lu, Hongzhi; He, Yu; Lin, Lin; Qi, Zhengqin; Ma, Li; Li, Li; Su, Ying

    2016-02-01

    Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a lncRNA playing oncogenic role in several cancers, including cervical cancer. However, its role in radiosensitivity of cervical cancer is not yet well understood. This study explored the role of MALAT1 in radiosensitivity of high-risk human papillomavirus (HR-HPV)-positive cervical cancer and whether there is a ceRNA mechanism which participated in its regulation over radiosensitivity. Based on tissue samples from 50 cervical cancer cases and 25 healthy controls, we found MALAT1 expression was significantly higher in radioresistant than in radiosensitive cancer cases. In addition, MALAT1 and miR-145 expression inversely changed in response to irradiation in HR-HPV+ cervical cancer cells. By using clonogenic assay and flow cytometry analysis of cell cycle distribution and apoptosis, we found CaSki and Hela cells with knockdown of MALAT1 had significantly lower colony formation, higher ratio of G2/M phase block and higher ratio of cell apoptosis. By performing RNA-binding protein immunoprecipitation (RIP) assay and RNA pull-down assay, we confirmed that miR-145 and MALAT1 were in the same Ago2 complex and there was a reciprocal repression between them. Then, we explored the function of MALAT1-miR-145 in radiosensitivity of cervical cancers cells and demonstrated that si-MALAT1 and miR-145 had some level of synergic effect in reducing cancer cell colony formation, cell cycle regulation, and inducing apoptosis. These findings provide an important clue about microRNA-lncRNA interaction in the mechanism of radioresistance of cervical cancer.

  10. Role of NAD+-Dependent Malate Dehydrogenase in the Metabolism of Methylomicrobium alcaliphilum 20Z and Methylosinus trichosporium OB3b

    PubMed Central

    Rozova, Olga N.; Khmelenina, Valentina N.; Bocharova, Ksenia A.; Mustakhimov, Ildar I.; Trotsenko, Yuri A.

    2015-01-01

    We have expressed the l-malate dehydrogenase (MDH) genes from aerobic methanotrophs Methylomicrobium alcaliphilum 20Z and Methylosinus trichosporium OB3b as his-tagged proteins in Escherichia coli. The substrate specificities, enzymatic kinetics and oligomeric states of the MDHs have been characterized. Both MDHs were NAD+-specific and thermostable enzymes not affected by metal ions or various organic metabolites. The MDH from M. alcaliphilum 20Z was a homodimeric (2 × 35 kDa) enzyme displaying nearly equal reductive (malate formation) and oxidative (oxaloacetate formation) activities and higher affinity to malate (Km = 0.11 mM) than to oxaloacetate (Km = 0.34 mM). The MDH from M. trichosporium OB3b was homotetrameric (4 × 35 kDa), two-fold more active in the reaction of oxaloacetate reduction compared to malate oxidation and exhibiting higher affinity to oxaloacetate (Km = 0.059 mM) than to malate (Km = 1.28 mM). The kcat/Km ratios indicated that the enzyme from M. alcaliphilum 20Z had a remarkably high catalytic efficiency for malate oxidation, while the MDH of M. trichosporium OB3b was preferable for oxaloacetate reduction. The metabolic roles of the enzymes in the specific metabolism of the two methanotrophs are discussed.

  11. Malate Plays a Crucial Role in Starch Metabolism, Ripening, and Soluble Solid Content of Tomato Fruit and Affects Postharvest Softening[W][OA

    PubMed Central

    Centeno, Danilo C.; Osorio, Sonia; Nunes-Nesi, Adriano; Bertolo, Ana L.F.; Carneiro, Raphael T.; Araújo, Wagner L.; Steinhauser, Marie-Caroline; Michalska, Justyna; Rohrmann, Johannes; Geigenberger, Peter; Oliver, Sandra N.; Stitt, Mark; Carrari, Fernando; Rose, Jocelyn K.C.; Fernie, Alisdair R.

    2011-01-01

    Despite the fact that the organic acid content of a fruit is regarded as one of its most commercially important quality traits when assessed by the consumer, relatively little is known concerning the physiological importance of organic acid metabolism for the fruit itself. Here, we evaluate the effect of modifying malate metabolism in a fruit-specific manner, by reduction of the activities of either mitochondrial malate dehydrogenase or fumarase, via targeted antisense approaches in tomato (Solanum lycopersicum). While these genetic perturbations had relatively little effect on the total fruit yield, they had dramatic consequences for fruit metabolism, as well as unanticipated changes in postharvest shelf life and susceptibility to bacterial infection. Detailed characterization suggested that the rate of ripening was essentially unaltered but that lines containing higher malate were characterized by lower levels of transitory starch and a lower soluble sugars content at harvest, whereas those with lower malate contained higher levels of these carbohydrates. Analysis of the activation state of ADP-glucose pyrophosphorylase revealed that it correlated with the accumulation of transitory starch. Taken together with the altered activation state of the plastidial malate dehydrogenase and the modified pigment biosynthesis of the transgenic lines, these results suggest that the phenotypes are due to an altered cellular redox status. The combined data reveal the importance of malate metabolism in tomato fruit metabolism and development and confirm the importance of transitory starch in the determination of agronomic yield in this species. PMID:21239646

  12. LncRNA MALAT1 functions as a competing endogenous RNA to regulate ZEB2 expression by sponging miR-200s in clear cell kidney carcinoma.

    PubMed

    Xiao, Haibing; Tang, Kun; Liu, Peijun; Chen, Ke; Hu, Junhui; Zeng, Jin; Xiao, Wei; Yu, Gan; Yao, Weiming; Zhou, Hui; Li, Heng; Pan, Yingtian; Li, Anping; Ye, Zhangqun; Wang, Ji; Xu, Hua; Huang, Qihong

    2015-11-10

    Long non-coding RNA (lncRNAs) play a critical role in the development of cancers. LncRNA metastasis-associated lung adenocarcinoma transcript 1(MALAT1) has recently been identified to be involved in tumorigenesis of several cancers such as lung cancer, bladder cancer and so on. Here, we found that MALAT1 exist a higher fold change (Tumor/Normal) in clear cell kidney carcinoma (KIRC) from The Cancer Genome Atlas (TCGA) Data Portal and a negative correlation with miR-200s family. We further demonstrated MALAT1 promote KIRC proliferation and metastasis through sponging miR-200s in vitro and in vivo. In addition, miR-200c can partly reverse the MALAT1's stimulation on proliferation and metastasis in KIRC. In summary we unveil a branch of the MALAT1/miR-200s/ZEB2 pathway that regulates the progression of KIRC. The inhibition of MALAT1 expression may be a promising strategy for KIRC therapy.

  13. RBM24 suppresses cancer progression by upregulating miR-25 to target MALAT1 in nasopharyngeal carcinoma.

    PubMed

    Hua, Wen-Feng; Zhong, Qian; Xia, Tian-Liang; Chen, Qi; Zhang, Mei-Yin; Zhou, Ai-Jun; Tu, Zi-Wei; Qu, Chen; Li, Man-Zhi; Xia, Yun-Fei; Wang, Hui-Yun; Xie, Dan; Claret, Francois-Xavier; Song, Er-Wei; Zeng, Mu-Sheng

    2016-01-01

    Abnormal interaction between non-coding RNAs has been demonstrated to be a common molecular event in various human cancers, but its significance and underlying mechanisms have not been well documented. RNA-binding proteins (RBPs) are key regulators of RNA transcription and post-transcriptional processing. In this study, we found that RNA-binding protein 24 (RBM24) was frequently downregulated in nasopharyngeal carcinoma (NPC). The restoration of RBM24 expression suppressed NPC cellular proliferation, migration and invasion and impeded metastatic colonization in mouse models. Microarray analyses revealed that miR-25 expression was upregulated by RBM24 expression in NPC cells. Similarly, ectopic miR-25 expression suppressed NPC cellular growth and motility by targeting the pro-oncogenic lncRNA MALAT1, and the knockdown of MALAT1 expression exhibited similar effects as RBM24 restoration in NPC cells. Overall, these findings suggest a novel role of RBM24 as a tumor suppressor. Mechanistically, RBM24 acts at least in part through upregulating the expression of miR-25, which in turn targets MALAT1 for degradation. PMID:27584791

  14. A systems chemical biology study of malate synthase and isocitrate lyase inhibition in Mycobacterium tuberculosis during active and NRP growth.

    PubMed

    May, Elebeoba E; Leitão, Andrei; Tropsha, Alexander; Oprea, Tudor I

    2013-12-01

    The ability of Mycobacterium tuberculosis (Mtb) to survive in low oxygen environments enables the bacterium to persist in a latent state within host tissues. In vitro studies of Mtb growth have identified changes in isocitrate lyase (ICL) and malate synthase (MS) that enable bacterial persistence under low oxygen and other environmentally limiting conditions. Systems chemical biology (SCB) enables us to evaluate the effects of small molecule inhibitors not only on the reaction catalyzed by malate synthase and isocitrate lyase, but the effect on the complete tricarboxylic acid cycle (TCA) by taking into account complex network relationships within that system. To study the kinetic consequences of inhibition on persistent bacilli, we implement a systems-chemical biology (SCB) platform and perform a chemistry-centric analysis of key metabolic pathways believed to impact Mtb latency. We explore consequences of disrupting the function of malate synthase (MS) and isocitrate lyase (ICL) during aerobic and hypoxic non-replicating persistence (NRP) growth by using the SCB method to identify small molecules that inhibit the function of MS and ICL, and simulating the metabolic consequence of the disruption. Results indicate variations in target and non-target reaction steps, clear differences in the normal and low oxygen models, as well as dosage dependent response. Simulation results from singular and combined enzyme inhibition strategies suggest ICL may be the more effective target for chemotherapeutic treatment against Mtb growing in a microenvironment where oxygen is slowly depleted, which may favor persistence.

  15. RBM24 suppresses cancer progression by upregulating miR-25 to target MALAT1 in nasopharyngeal carcinoma

    PubMed Central

    Hua, Wen-Feng; Zhong, Qian; Xia, Tian-Liang; Chen, Qi; Zhang, Mei-Yin; Zhou, Ai-Jun; Tu, Zi-Wei; Qu, Chen; Li, Man-Zhi; Xia, Yun-Fei; Wang, Hui-Yun; Xie, Dan; Claret, Francois-Xavier; Song, Er-Wei; Zeng, Mu-Sheng

    2016-01-01

    Abnormal interaction between non-coding RNAs has been demonstrated to be a common molecular event in various human cancers, but its significance and underlying mechanisms have not been well documented. RNA-binding proteins (RBPs) are key regulators of RNA transcription and post-transcriptional processing. In this study, we found that RNA-binding protein 24 (RBM24) was frequently downregulated in nasopharyngeal carcinoma (NPC). The restoration of RBM24 expression suppressed NPC cellular proliferation, migration and invasion and impeded metastatic colonization in mouse models. Microarray analyses revealed that miR-25 expression was upregulated by RBM24 expression in NPC cells. Similarly, ectopic miR-25 expression suppressed NPC cellular growth and motility by targeting the pro-oncogenic lncRNA MALAT1, and the knockdown of MALAT1 expression exhibited similar effects as RBM24 restoration in NPC cells. Overall, these findings suggest a novel role of RBM24 as a tumor suppressor. Mechanistically, RBM24 acts at least in part through upregulating the expression of miR-25, which in turn targets MALAT1 for degradation. PMID:27584791

  16. A Systems Chemical Biology Study of Malate Synthase and Isocitrate Lyase Inhibition in Mycobacterium tuberculosis During Active and NRP Growth

    PubMed Central

    May, Elebeoba E.; Leitão, Andrei; Tropsha, Alexander; Oprea, Tudor I.

    2013-01-01

    The ability of Mycobacterium tuberculosis (Mtb) to survive in low oxygen environments enables the bacterium to persist in a latent state within host tissues. In vitro studies of Mtb growth have identified changes in isocitrate lyase (ICL) and malate synthase (MS) that enable bacterial persistent under low oxygen and other environmentally limiting conditions. Systems chemical biology (SCB) enables us to evaluate the effects of small molecule inhibitors not only on the reaction catalyzed by malate synthase and isocitrate lyase, but the effect on the complete tricarboxylic acid cycle (TCA) by taking into account complex network relationships within that system. To study the kinetic consequences of inhibition on persistent bacilli, we implement a systems-chemical biology (SCB) platform and perform a chemistry-centric analysis of key metabolic pathways believed to impact Mtb latency. We explore consequences of disrupting the function of malate synthase (MS) and isocitrate lyase (ICL) during aerobic and hypoxic non-replicating persistence (NRP) growth by using the SCB method to identify small molecules that inhibit the function of MS and ICL, and simulating the metabolic consequence of the disruption. Results indicate variations in target and non-target reaction steps, clear differences in the normal and low oxygen models, as well as dosage dependent response. Simulation results from singular and combined enzyme inhibition strategies suggest ICL may be the more effective target for chemotherapeutic treatment against Mtb growing in a microenvironment where oxygen is slowly depleted, which may favor persistence. PMID:24121675

  17. A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration

    PubMed Central

    Jang, Kusik; Kim, Inhyub; Kim, Bo-Kyung; Lee, Kyeong; Won, Misun

    2016-01-01

    We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhibited significant growth inhibition of human colorectal cancer HCT116 cells. Compound 7 demonstrated substantial anti-tumor efficacy in an in vivo xenograft assay using HCT116 mouse model. Taken together, a novel MDH2 inhibitor, compound 7, suppressed HIF-1α accumulation via reduction of oxygen consumption and ATP production, integrating metabolism into anti-cancer efficacy in cancer cells. PMID:27611801

  18. Partial protective immunity against toxoplasmosis in mice elicited by recombinant Toxoplasma gondii malate dehydrogenase.

    PubMed

    Liu, Zhuanzhuan; Yuan, Fei; Yang, Yanping; Yin, Litian; Liu, Yisheng; Wang, Yanjuan; Zheng, Kuiyang; Cao, Jianping

    2016-02-10

    Toxoplasma gondii can infect humans and wildlife, sometimes causing serious clinical presentations. Currently, no viable vaccine or effective drug strategies exist to prevent and control toxoplasmosis. T. gondii malate dehydrogenase (TgMDH) is a crucial enzyme in cellular redox reactions and has been shown to be an immunogenic compound that could be a potential vaccine candidate. Here, we investigate the protective efficacy of recombinant TgMDH (rTgMDH) against T. gondii infection in BALB/c mice. All mice were vaccinated via the nasal route. We determined the optimal vaccination dose by monitoring systemic and mucosal immune responses. The results showed that mice vaccinated with 30 μg of rTgMDH produced the highest antibody titers in serum, a strong lymphoproliferative response, marked increases in their levels of IL-2 and IFN-γ, and significantly greater levels of specific secretory IgA (sIgA) in mucosal washes. In addition, the vaccinated mice were orally challenged with tachyzoites of the virulent T. gondii RH strain 2 weeks after the final vaccination. Compared to the control group, we found that vaccination with rTgMDH increased the survival rate of infected mice by 47% and also significantly reduced the tachyzoite loads in their liver (by 58%) and brain (by 41%). Therefore, the rTgMDH protein triggers a strong systemic and mucosal immune response and provides partial protection against T. gondii infection.

  19. Cloning, overexpression, purification and crystallization of malate dehydrogenase from Thermus thermophilus

    PubMed Central

    Chang, Yu-Yung; Hung, Chih-Hung; Hwang, Tzann-Shun; Hsu, Chun-Hua

    2013-01-01

    Malate dehydrogenase (MDH) has been used as a conjugate for enzyme immunoassay of a wide variety of compounds, such as drugs of abuse, drugs used in repetitive therapeutic application and hormones. In consideration of the various biotechnological applications of MDH, investigations of MDH from Thermus thermophilus were carried out to further understand the properties of this enzyme. The DNA fragment containing the open reading frame of mdh was amplified from the genomic DNA of T. thermophilus and cloned into the expression vector pET21b(+). The protein was expressed in a soluble form in Escherichia coli strain BL21(DE3). Homogeneous protein was obtained using a three-step procedure consisting of thermal treatment, Ni2+-chelating chromatography and size-exclusion chromatography. The purified MDH was crystallized and the crystals diffracted to a resolution of 1.80 Å on the BL13C1 beamline of the National Synchrotron Radiation Research Center (NSRRC), Taiwan. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 71.3, b = 86.1, c = 118.2 Å. The unit-cell volume of the crystal is compatible with the presence of two monomers in the asymmetric unit, with a corresponding Matthews coefficient V M of 2.52 Å3 Da−1 and a solvent content of 51.2%. The crystal structure of MDH has been solved by molecular replacement and is currently under refinement. PMID:24192361

  20. Ectopic Expression of the Chinese Cabbage Malate Dehydrogenase Gene Promotes Growth and Aluminum Resistance in Arabidopsis

    PubMed Central

    Li, Qing-Fei; Zhao, Jing; Zhang, Jing; Dai, Zi-Hui; Zhang, Lu-Gang

    2016-01-01

    Malate dehydrogenases (MDHs) are key metabolic enzymes that play important roles in plant growth and development. In the present study, we isolated the full-length and coding sequences of BraMDH from Chinese cabbage [Brassica campestris L. ssp. pekinensis (Lour) Olsson]. We conducted bioinformatics analysis and a subcellular localization assay, which revealed that the BraMDH gene sequence contained no introns and that BraMDH is localized to the chloroplast. In addition, the expression pattern of BraMDH in Chinese cabbage was investigated, which revealed that BraMDH was heavily expressed in inflorescence apical meristems, as well as the effect of BraMDH overexpression in two homozygous transgenic Arabidopsis lines, which resulted in early bolting and taller inflorescence stems. Furthermore, the fresh and dry weights of aerial tissue from the transgenic Arabidopsis plants were significantly higher than those from the corresponding wild-type plants, as were plant height, the number of rosette leaves, and the number of siliques produced, and the transgenic plants also exhibited stronger aluminum resistance when treated with AlCl3. Therefore, our results suggest that BraMDH has a dramatic effect on plant growth and that the gene is involved in both plant growth and aluminum resistance. PMID:27536317

  1. [Use of citrulline malate (stimol) in patients with autonomic dystonia associated with arterial hypotension].

    PubMed

    Oknin, V Iu; Fedotova, A V; Veĭn, A M

    1999-01-01

    To study possibilities of a therapeutic correction of asthenic syndrome in individuals with chronic arterial hypotension with malate citrulline, the study was made of 12 women and 3 men with psychoautonomic syndrome (autonomic dystonia), combined with chronic constitutional arterial hypotension. Their age was from 27 to 45 years (mean age--37.6). A control group comprised 14 healthy individuals. Both a state of autonomic nervous system and manifestations of arterial hyportension were analyzed by means of complex scored questionnaires. Mental condition was assessed by the tests of Spilberger (evaluation of reactive and personal anxiety) and of Beck (estimation of depressive manifestations). In all the examined individuals with chronic arterial hypotension, there was psychoautonomic syndrome combined with complaints to asthenic manifestations, namely, to low performance and fatigue. Stimol was prescribed in the form of 50% solution in daily dose of 6 g (3 administrations). The therapy resulted in regression of clinical manifestations of both psychoautonomic syndrome and asthenic symptoms. A mechanism of the drug's action works through favourable changes in cerebral and muscular cells, that, in turn, had an influence on other manifestations of psychoautonomic syndrome. PMID:11530455

  2. Beneficial effects of citrulline malate on skeletal muscle function in endotoxemic rat.

    PubMed

    Giannesini, Benoît; Izquierdo, Marguerite; Le Fur, Yann; Cozzone, Patrick J; Verleye, Marc; Le Guern, Marie-Emmanuelle; Gillardin, Jean-Marie; Bendahan, David

    2009-01-01

    Although citrulline malate (CM; CAS 54940-97-5, Stimol) is used against fatigue states, its anti-asthenic effect remains poorly documented. The objective of this double-blind study was to evaluate the effect of oral ingestion of CM on a rat model of asthenia, using in situ (31)Phosphorus magnetic resonance spectroscopy ((31)P-MRS). Muscle weakness was induced by intraperitoneal injections of Klebsiella pneumoniae endotoxin (lipopolysaccharides at 3 mg/kg) at t(0) and t(0)+24 h. For each animal, muscle function was investigated strictly non-invasively before (t(0)-24 h) and during (t(0)+48 h) endotoxemia, through a standardized rest-stimulation-recovery protocol. The transcutaneous electrical stimulation protocol consisted of 5.7 min of repeated isometric contractions at a frequency of 3.3 Hz, and force production was measured with an ergometer. CM supplementation in endotoxemic animals prevented the basal phosphocreatine/ATP ratio reduction and normalized the intracellular pH (pH(i)) time-course during muscular activity as a sign of an effect at the muscle energetics level. In addition, CM treatment avoided the endotoxemia-induced decline in developed force. These results demonstrate the efficiency of CM for limiting skeletal muscle dysfunction in rats treated with bacterial endotoxin. PMID:19036344

  3. Structural basis for the alteration of coenzyme specificity in a malate dehydrogenase mutant

    SciTech Connect

    Tomita, Takeo; Fushinobu, Shinya; Kuzuyama, Tomohisa; Nishiyama, Makoto . E-mail: umanis@mail.ecc.u-tokyo.ac.jp

    2006-08-25

    To elucidate the structural basis for the alteration of coenzyme specificity from NADH toward NADPH in a malate dehydrogenase mutant EX7 from Thermus flavus, we determined the crystal structures at 2.0 A resolution of EX7 complexed with NADPH and NADH, respectively. In the EX7-NADPH complex, Ser42 and Ser45 form hydrogen bonds with the 2'-phosphate group of the adenine ribose of NADPH, although the adenine moiety is not seen in the electron density map. In contrast, although Ser42 and Ser45 occupy a similar position in the EX7-NADH complex structure, both the adenine and adenine ribose moieties of NADH are missing in the map. These results and kinetic analysis of site-directed mutant enzymes indicate (1) that the preference of EX7 for NADPH over NADH is ascribed to the recognition of the 2'-phosphate group by two Ser and Arg44, and (2) that the adenine moiety of NADPH is not recognized in this mutant.

  4. Kinetic simulation of malate-aspartate and citrate-pyruvate shuttles in association with Krebs cycle.

    PubMed

    Korla, Kalyani; Vadlakonda, Lakshmipathi; Mitra, Chanchal K

    2015-01-01

    In the present work, we have kinetically simulated two mitochondrial shuttles, malate-aspartate shuttle (used for transferring reducing equivalents) and citrate-pyruvate shuttle (used for transferring carbon skeletons). However, the functions of these shuttles are not limited to the points mentioned above, and they can be used in different arrangements to meet different cellular requirements. Both the shuttles are intricately associated with Krebs cycle through the metabolites involved. The study of this system of shuttles and Krebs cycle explores the response of the system in different metabolic environments. Here, we have simulated these subsets individually and then combined them to study the interactions among them and to bring out the dynamics of these pathways in focus. Four antiports and a pyruvate pump were modelled along with the metabolic reactions on both sides of the inner mitochondrial membrane. Michaelis-Menten approach was extended for deriving rate equations of every component of the system. Kinetic simulation was carried out using ordinary differential equation solver in GNU Octave. It was observed that all the components attained steady state, sooner or later, depending on the system conditions. Progress curves and phase plots were plotted to understand the steady state behaviour of the metabolites involved. A comparative analysis between experimental and simulated data show fair agreement thus validating the usefulness and applicability of the model.

  5. Synthesis and crystal structures of two nickel coordination polymers generated from asymmetric malate ligand

    SciTech Connect

    Guo Yaqin; Xiao Dongrong; Wang Enbo . E-mail: wangenbo@public.cc.jl.cn; Lu Ying; Lue Jian; Xu Xinxin; Xu Lin

    2005-03-15

    Two nickel coordination polymers [Ni(H{sub 2}O)(C{sub 4}H{sub 4}O{sub 5})].H{sub 2}O 1 and [Ni(H{sub 2}O)(mal)(phen)] 2, have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Crystal data for 1: C{sub 4}H{sub 8}O{sub 7}Ni, monoclinic Cc, a=13.156(3)A, b=7.5436(15)A, c=9.6982(19)A, {beta}=130.96(3){sup o}, Z=4. Crystal data for 2: C{sub 16}H{sub 14}N{sub 2}O{sub 6}Ni, orthorhombic Pna2{sub 1}, a=9.6113(19)A, b=19.691(4)A, c=8.0944(16)A, Z=4. Compound 1 is constructed from [Ni(H{sub 2}O)(C{sub 4}H{sub 4}O{sub 5})] sheets pillared through {beta}-carboxylate groups into a 3D framework, which exhibits a diamond-like network. Compound 2 exhibits a 3D supramolecular network. To our knowledge, compound 1 represents the first diamond-like topology in the system of metal-malate. Other characterizations by elemental analysis, IR and TG are also described. The magnetic behavior of compound 1 has been studied.

  6. Interface matters: the stiffness route to stability of a thermophilic tetrameric malate dehydrogenase.

    PubMed

    Kalimeri, Maria; Girard, Eric; Madern, Dominique; Sterpone, Fabio

    2014-01-01

    In this work we investigate by computational means the behavior of two orthologous bacterial proteins, a mesophilic and a thermophilic tetrameric malate dehydrogenase (MalDH), at different temperatures. Namely, we quantify how protein mechanical rigidity at different length- and time-scales correlates to protein thermophilicity as commonly believed. In particular by using a clustering analysis strategy to explore the conformational space of the folded proteins, we show that at ambient conditions and at the molecular length-scale the thermophilic variant is indeed more rigid that the mesophilic one. This rigidification is the result of more efficient inter-domain interactions, the strength of which is further quantified via ad hoc free energy calculations. When considered isolated, the thermophilic domain is indeed more flexible than the respective mesophilic one. Upon oligomerization, the induced stiffening of the thermophilic protein propagates from the interface to the active site where the loop, controlling the access to the catalytic pocket, anchors down via an extended network of ion-pairs. On the contrary in the mesophilic tetramer the loop is highly mobile. Simulations at high temperature, could not re-activate the mobility of the loop in the thermophile. This finding opens questions on the similarities of the binding processes for these two homologues at their optimal working temperature and suggests for the thermophilic variant a possible cooperative role of cofactor/substrate.

  7. Pathway of Photosynthetic Malate Formation in Vitis vinifera, a C3 Plant 1

    PubMed Central

    Ruffner, Hans Peter; Brem, Susanne; Rast, Dora M.

    1983-01-01

    The time course of intramolecular isotope distribution in phosphoglyceric acid and serine was determined after exposure of grape leaf discs (Vitis vinifera L.) to 14CO2 (1000 microliters per liter) for variable metabolic periods, and the labeling patterns were compared with the respective isotope distribution in the C1-3 fragment of malic acid. The results clearly support the classical concept of a close precursor-product relationship between photosynthetic phosphoglycerate and malic acid. Under the assimilatory conditions used in this study, there was no indication of an immediate carbon transfer from serine to malate as has been suggested for C3 plants (Kent et al. 1974 Plant Physiol 53: 491-495) because of a coincident labeling of these compounds in Vicia faba. According to our data, previous evidence in favor of this hypothetical pathway is based largely on an unusual 14C distribution in serine, due to an extreme suppression of photorespiration, as well as on arbitrary comparisons between compounds of divergent kinetic characteristics and consequently different degrees of metabolic label randomization. PMID:16663263

  8. Metabolic fingerprint of ischaemic cardioprotection: importance of the malate-aspartate shuttle.

    PubMed

    Nielsen, Torsten Toftegaard; Støttrup, Nicolaj Brejnholt; Løfgren, Bo; Bøtker, Hans Erik

    2011-08-01

    The convergence of cardioprotective intracellular signalling pathways to modulate mitochondrial function as an end-target of cytoprotective stimuli is well described. However, our understanding of whether the complementary changes in mitochondrial energy metabolism are secondary responses or inherent mechanisms of ischaemic cardioprotection remains incomplete. In the heart, the malate-aspartate shuttle (MAS) constitutes the primary metabolic pathway for transfer of reducing equivalents from the cytosol into the mitochondria for oxidation. The flux of MAS is tightly linked to the flux of the tricarboxylic acid cycle and the electron transport chain, partly by the amino acid l-glutamate. In addition, emerging evidence suggests the MAS is an important regulator of cytosolic and mitochondrial calcium homeostasis. In the isolated rat heart, inhibition of MAS during ischaemia and early reperfusion by the aminotransferase inhibitor aminooxyacetate induces infarct limitation, improves haemodynamic responses, and modulates glucose metabolism, analogous to effects observed in classical ischaemic preconditioning. On the basis of these findings, the mechanisms through which MAS preserves mitochondrial function and cell survival are reviewed. We conclude that the available evidence is supportive of a down-regulation of mitochondrial respiration during lethal ischaemia with a gradual 'wake-up' during reperfusion as a pivotal feature of ischaemic cardioprotection. Finally, comments on modulating myocardial energy metabolism by the cardioprotective amino acids glutamate and glutamine are given.

  9. Nanostructurated complexes of poly(beta,L-malate) and cationic surfactants: synthesis, characterization and structural aspects.

    PubMed

    Portilla-Arias, José A; García-Alvarez, Montserrat; Martínez de Ilarduya, Antxon; Holler, Eggerhard; Muñoz-Guerra, Sebastián

    2006-01-01

    Ionic complexes of microbially produced poly(beta,L-malic acid) and alkyltrimethylammonium surfactants with linear alkyl chains containing even numbers of carbon atoms from 14 up to 22, were investigated. Complexes with a stoichiometric or nearly stoichiometric composition were prepared by precipitation from equimolar mixtures of aqueous solutions of the two components. All complexes were found to adopt supramolecular stratified structures made of alternating layers of poly(beta,L-malate) and surfactant with a periodicity on the length scale of 3-5 nm, which increased proportionally to the length of the polymethylene chain. In these complexes, alkyl side chains with more than 16 carbon atoms were partially crystallized showing reversible melting at temperatures between 40 and 70 degrees C. After melting, a smectic LC phase that isotropicized at approximately 100 degrees C was observed for all of the complexes. Conformational and dimensional changes taking place in the complexes by effect of heating were analyzed by (13)C CP-MAS NMR and powder X-ray diffraction.

  10. Ectopic Expression of the Chinese Cabbage Malate Dehydrogenase Gene Promotes Growth and Aluminum Resistance in Arabidopsis.

    PubMed

    Li, Qing-Fei; Zhao, Jing; Zhang, Jing; Dai, Zi-Hui; Zhang, Lu-Gang

    2016-01-01

    Malate dehydrogenases (MDHs) are key metabolic enzymes that play important roles in plant growth and development. In the present study, we isolated the full-length and coding sequences of BraMDH from Chinese cabbage [Brassica campestris L. ssp. pekinensis (Lour) Olsson]. We conducted bioinformatics analysis and a subcellular localization assay, which revealed that the BraMDH gene sequence contained no introns and that BraMDH is localized to the chloroplast. In addition, the expression pattern of BraMDH in Chinese cabbage was investigated, which revealed that BraMDH was heavily expressed in inflorescence apical meristems, as well as the effect of BraMDH overexpression in two homozygous transgenic Arabidopsis lines, which resulted in early bolting and taller inflorescence stems. Furthermore, the fresh and dry weights of aerial tissue from the transgenic Arabidopsis plants were significantly higher than those from the corresponding wild-type plants, as were plant height, the number of rosette leaves, and the number of siliques produced, and the transgenic plants also exhibited stronger aluminum resistance when treated with AlCl3. Therefore, our results suggest that BraMDH has a dramatic effect on plant growth and that the gene is involved in both plant growth and aluminum resistance. PMID:27536317

  11. A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration.

    PubMed

    Ban, Hyun Seung; Xu, Xuezhen; Jang, Kusik; Kim, Inhyub; Kim, Bo-Kyung; Lee, Kyeong; Won, Misun

    2016-01-01

    We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhibited significant growth inhibition of human colorectal cancer HCT116 cells. Compound 7 demonstrated substantial anti-tumor efficacy in an in vivo xenograft assay using HCT116 mouse model. Taken together, a novel MDH2 inhibitor, compound 7, suppressed HIF-1α accumulation via reduction of oxygen consumption and ATP production, integrating metabolism into anti-cancer efficacy in cancer cells. PMID:27611801

  12. Lactate oxidation at the mitochondria: a lactate-malate-aspartate shuttle at work

    PubMed Central

    Kane, Daniel A.

    2014-01-01

    Lactate, the conjugate base of lactic acid occurring in aqueous biological fluids, has been derided as a “dead-end” waste product of anaerobic metabolism. Catalyzed by the near-equilibrium enzyme lactate dehydrogenase (LDH), the reduction of pyruvate to lactate is thought to serve to regenerate the NAD+ necessary for continued glycolytic flux. Reaction kinetics for LDH imply that lactate oxidation is rarely favored in the tissues of its own production. However, a substantial body of research directly contradicts any notion that LDH invariably operates unidirectionally in vivo. In the current Perspective, a model is forwarded in which the continuous formation and oxidation of lactate serves as a mitochondrial electron shuttle, whereby lactate generated in the cytosol of the cell is oxidized at the mitochondria of the same cell. From this perspective, an intracellular lactate shuttle operates much like the malate-aspartate shuttle (MAS); it is also proposed that the two shuttles are necessarily interconnected in a lactate-MAS. Among the requisite features of such a model, significant compartmentalization of LDH, much like the creatine kinase of the phosphocreatine shuttle, would facilitate net cellular lactate oxidation in a variety of cell types. PMID:25505376

  13. Interface Matters: The Stiffness Route to Stability of a Thermophilic Tetrameric Malate Dehydrogenase

    PubMed Central

    Kalimeri, Maria; Girard, Eric; Madern, Dominique; Sterpone, Fabio

    2014-01-01

    In this work we investigate by computational means the behavior of two orthologous bacterial proteins, a mesophilic and a thermophilic tetrameric malate dehydrogenase (MalDH), at different temperatures. Namely, we quantify how protein mechanical rigidity at different length- and time-scales correlates to protein thermophilicity as commonly believed. In particular by using a clustering analysis strategy to explore the conformational space of the folded proteins, we show that at ambient conditions and at the molecular length-scale the thermophilic variant is indeed more rigid that the mesophilic one. This rigidification is the result of more efficient inter-domain interactions, the strength of which is further quantified via ad hoc free energy calculations. When considered isolated, the thermophilic domain is indeed more flexible than the respective mesophilic one. Upon oligomerization, the induced stiffening of the thermophilic protein propagates from the interface to the active site where the loop, controlling the access to the catalytic pocket, anchors down via an extended network of ion-pairs. On the contrary in the mesophilic tetramer the loop is highly mobile. Simulations at high temperature, could not re-activate the mobility of the loop in the thermophile. This finding opens questions on the similarities of the binding processes for these two homologues at their optimal working temperature and suggests for the thermophilic variant a possible cooperative role of cofactor/substrate. PMID:25437494

  14. Alternative Oxidase Pathway Optimizes Photosynthesis During Osmotic and Temperature Stress by Regulating Cellular ROS, Malate Valve and Antioxidative Systems

    PubMed Central

    Vishwakarma, Abhaypratap; Raghavendra, Agepati S.; Padmasree, Kollipara

    2016-01-01

    The present study reveals the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under osmotic and temperature stress conditions in the mesophyll protoplasts of Pisum sativum. The responses of photosynthesis and respiration were monitored at saturating light intensity of 1000 μmoles m–2 s–1 at 25°C under a range of sorbitol concentrations from 0.4 to 1.0 M to induce hyper-osmotic stress and by varying the temperature of the thermo-jacketed pre-incubation chamber from 25 to 10°C to impose sub-optimal temperature stress. Compared to controls (0.4 M sorbitol and 25°C), the mesophyll protoplasts showed remarkable decrease in NaHCO3-dependent O2 evolution (indicator of photosynthetic carbon assimilation), under both hyper-osmotic (1.0 M sorbitol) and sub-optimal temperature stress conditions (10°C), while the decrease in rates of respiratory O2 uptake were marginal. The capacity of AOX pathway increased significantly in parallel to increase in intracellular pyruvate and reactive oxygen species (ROS) levels under both hyper-osmotic stress and sub-optimal temperature stress under the background of saturating light. The ratio of redox couple (Malate/OAA) related to malate valve increased in contrast to the ratio of redox couple (GSH/GSSG) related to antioxidative system during hyper-osmotic stress. Further, the ratio of GSH/GSSG decreased in the presence of sub-optimal temperature, while the ratio of Malate/OAA showed no visible changes. Also, the redox ratios of pyridine nucleotides increased under hyper-osmotic (NADH/NAD) and sub-optimal temperature (NADPH/NADP) stresses, respectively. However, upon restriction of AOX pathway by using salicylhydroxamic acid (SHAM), the observed changes in NaHCO3-dependent O2 evolution, cellular ROS, redox ratios of Malate/OAA, NAD(P)H/NAD(P) and GSH/GSSG were further aggravated under stress conditions with concomitant modulations in NADP-MDH and antioxidant enzymes. Taken together, the results indicated

  15. Identification of a novel fumarase C from Streptomyces lividans TK54 as a good candidate for L-malate production.

    PubMed

    Su, Rui-Rui; Wang, Ao; Hou, Song-Tao; Gao, Peng; Zhu, Guo-Ping; Wang, Wen

    2014-01-01

    Fumarase is a key enzyme that catalyzes the reversible hydration of fumarate to L-malate in the tricarboxylic acid cycle. This reaction has been extensively utilized for industrial applications in producing L-malate. In this study, a fumarase C gene from Streptomyces lividans TK54 (slFumC) was cloned and expressed as a fused protein (SlFumC) in Escherichia coli. The molecular mass of SlFumC was about 49 kDa determined by SDS-PAGE. Kinetic studies showed that the K m value of SlFumC for L-malate increased by approximately 8.5-fold at pH 6.5 (6.7 ± 0.81 mM) to 8.0 (57.0 ± 1.12 mM), which was higher than some known fumarases. The catalytic efficiency (k cat) and the specific activity increased by about 9.5-fold at pH 6.5 (65 s(-1)) to 8.0 (620 s(-1)) and from 79 U/mg at pH 6.5 to 752 U/mg at pH 8.0, respectively. Therefore, SlFumC may acquire strong catalytic ability by increasing pH to partially compensate for the loss of substrate affinity. The enzyme also showed substrate inhibition phenomenon, which is pH-dependent. Specific activity of SlFumC was gradually enhanced with increasing phosphate concentrations. However, no inhibition was observed at high concentration of phosphate ion, which was distinctly different in case of other Class II fumarases. In industrial process, the reaction temperatures for L-malate production are usually set between 40 and 60 °C. The recombinant SlFumC displayed maximal activity at 45 °C and remained over 85 % of original activity after 48 h incubation at 40 °C, which was more thermostable than other fumarases from Streptomyces and make it an efficient enzyme for use in the industrial production of L-malate.

  16. Gradual neofunctionalization in the convergent evolution of trichomonad lactate and malate dehydrogenases

    PubMed Central

    Steindel, Phillip A.; Chen, Emily H.; Wirth, Jacob D.

    2016-01-01

    Abstract Lactate and malate dehydrogenases (LDH and MDH) are homologous, core metabolic enzymes common to nearly all living organisms. LDHs have evolved convergently from MDHs at least four times, achieving altered substrate specificity by a different mechanism each time. For instance, the LDH of anaerobic trichomonad parasites recently evolved independently from an ancestral trichomonad MDH by gene duplication. LDH plays a central role in trichomonad metabolism by catalyzing the reduction of pyruvate to lactate, thereby regenerating the NAD+ required for glycolysis. Using ancestral reconstruction methods, we identified the biochemical and evolutionary mechanisms responsible for this convergent event. The last common ancestor of these enzymes was a highly specific MDH, similar to modern trichomonad MDHs. In contrast, the LDH lineage evolved promiscuous activity by relaxing specificity in a gradual process of neofunctionalization involving one highly detrimental substitution at the “specificity residue” (R91L) and many additional mutations of small effect. L91 has different functional consequences in LDHs and in MDHs, indicating a prominent role for epistasis. Crystal structures of modern‐day and ancestral enzymes show that the evolution of substrate specificity paralleled structural changes in dimerization and α‐helix orientation. The relatively small “specificity residue” of the trichomonad LDHs can accommodate a range of substrate sizes and may permit solvent to access the active site, both of which promote substrate promiscuity. The trichomonad LDHs present a multi‐faceted counterpoint to the independent evolution of LDHs in other organisms and illustrate the diverse mechanisms by which protein function, structure, and stability coevolve. PMID:26889885

  17. Sunitinib malate and figitumumab in solitary fibrous tumor: patterns and molecular bases of tumor response.

    PubMed

    Stacchiotti, Silvia; Negri, Tiziana; Palassini, Elena; Conca, Elena; Gronchi, Alessandro; Morosi, Carlo; Messina, Antonella; Pastorino, Ugo; Pierotti, Marco A; Casali, Paolo G; Pilotti, Silvana

    2010-05-01

    Antiangiogenic treatment activity has been reported in solitary fibrous tumor (SFT), a rare and little chemosensitive sarcoma. We explored the activity of sunitinib malate (SM) in SFT and studied receptor tyrosine kinase (RTK) activation profile. Eleven patients with progressive metastatic SFT resistant to chemotherapy were treated with continuous-dosing 37.5 mg/d SM on a named-use basis. One of them also received the insulin-like growth factor I receptor (IGFIR) inhibitor figitumumab after developing secondary resistance to SM. Besides, biochemical, molecular, and fluorescence in situ hybridization analyses were done in eight naïve SFTs whose cryopreserved material was available to clarify RTK upstream and downstream signaling. In two cases treated with SM and belonging to the naïve series, both pretreatment and posttreatment samples were available. Ten patients were evaluable for response to SM. The best response according to the Choi criteria was six partial response (all with Response Evaluation Criteria in Solid Tumors stable disease), one stable disease, and three progressive disease. Responses lasted >6 months in five patients. The eight naïve samples showed high expression/phosphorylation of PDGFRB, epidermal growth factor receptor, and IGFIR/IR, in the presence of their cognate ligands. Downstream pathways revealed expression/activation of Akt, extracellular signal-regulated kinase 1-2 and, closely related to SFT subtypes, of S6 and 4E-BP1. In two patients, whose pretreatment and posttreatment clinical and molecular status were available, biochemical data confirmed the activity of SM, although they also suggested a possible time-dependent shift of dominant RTK from PDGFRB to IGFIR/insulin receptor. A Response Evaluation Criteria in Solid Tumors partial response to figitumumab corroborated these findings. SM has antitumor activity in SFT, possibly through a PDGFRB-mediated mechanism, but treatments with IGFIR/insulin receptor and possibly epidermal

  18. The health benefits of calcium citrate malate: a review of the supporting science.

    PubMed

    Reinwald, Susan; Weaver, Connie M; Kester, Jeffrey J

    2008-01-01

    There has been considerable investigation into the health benefits of calcium citrate malate (CCM) since it was first patented in the late 1980s. This chapter is a comprehensive summary of the supporting science and available evidence on the bioavailability and health benefits of consuming CCM. It highlights the important roles that CCM can play during various life stages. CCM has been shown to facilitate calcium retention and bone accrual in children and adolescents. In adults, it effectively promotes the consolidation and maintenance of bone mass. In conjunction with vitamin D, CCM also decreases bone fracture risk in the elderly, slows the rate of bone loss in old age, and is of benefit to the health and well-being of postmenopausal women. CCM is exceptional in that it confers many unique benefits that go beyond bone health. Unlike other calcium sources that necessitate supplementation be in conjunction with a meal to ensure an appreciable benefit is derived, CCM can be consumed with or without food and delivers a significant nutritional benefit to individuals of all ages. The chemistry of CCM makes it a particularly beneficial calcium source for individuals with hypochlorydia or achlorydia, which generally includes the elderly and those on medications that decrease gastric acid secretion. CCM is also recognized as a calcium source that does not increase the risk of kidney stones, and in fact it protects against stone-forming potential. The versatile nature of CCM makes it a convenient and practical calcium salt for use in moist foods and beverages. The major factor that may preclude selection of CCM as a preferred calcium source is the higher cost compared to other sources of calcium commonly used for fortification (e.g., calcium carbonate and tricalcium phosphate). However, formation of CCM directly within beverages or other fluid foods and/or preparations, and the addition of a concentrated CCM solution or slurry, are relatively cost-effective methods by

  19. Characterization of the N-Acetyl-[alpha]-d-glucosaminyl l-Malate Synthase and Deacetylase Functions for Bacillithiol Biosynthesis in Bacillus anthracis

    SciTech Connect

    Parsonage, Derek; Newton, Gerald L.; Holder, Robert C.; Wallace, Bret D.; Paige, Carleitta; Hamilton, Chris J.; Dos Santos, Patricia C.; Redinbo, Matthew R.; Reid, Sean D.; Claiborne, Al

    2012-02-21

    Bacillithiol (Cys-GlcN-malate, BSH) has recently been identified as a novel low-molecular weight thiol in Bacillus anthracis, Staphylococcus aureus, and several other Gram-positive bacteria lacking glutathione and mycothiol. We have now characterized the first two enzymes for the BSH biosynthetic pathway in B. anthracis, which combine to produce {alpha}-D-glucosaminyl L-malate (GlcN-malate) from UDP-GlcNAc and L-malate. The structure of the GlcNAc-malate intermediate has been determined, as have the kinetic parameters for the BaBshA glycosyltransferase ({yields}GlcNAc-malate) and the BaBshB deacetylase ({yields}GlcN-malate). BSH is one of only two natural products reported to contain a malyl glycoside, and the crystal structure of the BaBshA-UDP-malate ternary complex, determined in this work at 3.3 {angstrom} resolution, identifies several active-site interactions important for the specific recognition of L-malate, but not other {alpha}-hydroxy acids, as the acceptor substrate. In sharp contrast to the structures reported for the GlcNAc-1-D-myo-inositol-3-phosphate synthase (MshA) apo and ternary complex forms, there is no major conformational change observed in the structures of the corresponding BaBshA forms. A mutant strain of B. anthracis deficient in the BshA glycosyltransferase fails to produce BSH, as predicted. This B. anthracis bshA locus (BA1558) has been identified in a transposon-site hybridization study as required for growth, sporulation, or germination [Day, W. A., Jr., Rasmussen, S. L., Carpenter, B. M., Peterson, S. N., and Friedlander, A. M. (2007) J. Bacteriol. 189, 3296-3301], suggesting that the biosynthesis of BSH could represent a target for the development of novel antimicrobials with broad-spectrum activity against Gram-positive pathogens like B. anthracis. The metabolites that function in thiol redox buffering and homeostasis in Bacillus are not well understood, and we present a composite picture based on this and other recent work.

  20. Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX.

    PubMed

    Dinakar, Challabathula; Raghavendra, Agepati S; Padmasree, Kollipara

    2010-05-01

    The present study shows the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under high light (HL). The responses of photosynthesis and respiration were monitored as O(2) evolution and O(2) uptake in mesophyll protoplasts of pea pre-incubated under different light intensities. Under HL (3000 micromol m(-2) s(-1)), mesophyll protoplasts showed remarkable decrease in the rates of NaHCO(3)-dependent O(2) evolution (indicator of photosynthetic carbon assimilation), while decrease in the rates of respiratory O(2) uptake were marginal. While the capacity of AOX pathway increased significantly by two fold under HL, the capacity of cytochrome oxidase (COX) pathway decreased by >50% compared with capacities under darkness and normal light (NL). Further, the total cellular levels of pyruvate and malate, which are assimilatory products of active photosynthesis and stimulators of AOX activity, were increased remarkably parallel to the increase in AOX protein under HL. Upon restriction of AOX pathway using salicylhydroxamic acid (SHAM), the observed decrease in NaHCO(3)-dependent O(2) evolution or p-benzoquinone (BQ)-dependent O(2) evolution [indicator of photosystem II (PSII) activity] and the increase in total cellular levels of pyruvate and malate were further aggravated/promoted under HL. The significance of raised malate and pyruvate levels in activation of AOX protein/AOX pathway, which in turn play an important role in dissipating excess chloroplastic reducing equivalents and sustenance of photosynthetic carbon assimilation to balance the effects of HL stress on photosynthesis, was depicted as a model.

  1. MdMYB1 Regulates Anthocyanin and Malate Accumulation by Directly Facilitating Their Transport into Vacuoles in Apples1[OPEN

    PubMed Central

    Hu, Da-Gang; Sun, Cui-Hui; Ma, Qi-Jun; You, Chun-Xiang; Hao, Yu-Jin

    2016-01-01

    Tonoplast transporters, including proton pumps and secondary transporters, are essential for plant cell function and for quality formation of fleshy fruits and ornamentals. Vacuolar transport of anthocyanins, malate, and other metabolites is directly or indirectly dependent on the H+-pumping activities of vacuolar H+-ATPase (VHA) and/or vacuolar H+-pyrophosphatase, but how these proton pumps are regulated in modulating vacuolar transport is largely unknown. Here, we report a transcription factor, MdMYB1, in apples that binds to the promoters of two genes encoding the B subunits of VHA, MdVHA-B1 and MdVHA-B2, to transcriptionally activate its expression, thereby enhancing VHA activity. A series of transgenic analyses in apples demonstrates that MdMYB1/10 controls cell pH and anthocyanin accumulation partially by regulating MdVHA-B1 and MdVHA-B2. Furthermore, several other direct target genes of MdMYB10 are identified, including MdVHA-E2, MdVHP1, MdMATE-LIKE1, and MdtDT, which are involved in H+-pumping or in the transport of anthocyanins and malates into vacuoles. Finally, we show that the mechanism by which MYB controls malate and anthocyanin accumulation in apples also operates in Arabidopsis (Arabidopsis thaliana). These findings provide novel insights into how MYB transcription factors directly modulate the vacuolar transport system in addition to anthocyanin biosynthesis, consequently controlling organ coloration and cell pH in plants. PMID:26637549

  2. Recurrent MALAT1-GLI1 oncogenic fusion and GLI1 up-regulation define a subset of plexiform fibromyxoma.

    PubMed

    Spans, Lien; Fletcher, Christopher Dm; Antonescu, Cristina R; Rouquette, Alexandre; Coindre, Jean-Michel; Sciot, Raf; Debiec-Rychter, Maria

    2016-07-01

    Plexiform fibromyxomas are rare neoplasms, being officially recognized as a distinct entity among benign mesenchymal gastric tumours in the 2010 WHO Classification of Tumours of the Digestive System. Characteristically, these tumours have a multinodular/plexiform growth pattern, and histologically contain variably cellular areas of bland myofibroblastic-type spindle cells embedded in an abundant myxoid matrix, rich in capillary-type vessels. As yet, the molecular and/or genetic features of these tumours are unknown. Here we describe a recurrent translocation, t(11;12)(q11;q13), involving the long non-coding gene metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and the gene glioma-associated oncogene homologue 1 (GLI1) in a subgroup of these tumours. The presence of the fusion transcript in our index case was confirmed using polymerase chain reaction (PCR) on genomic DNA, followed by Sanger sequencing. We showed that the truncated GLI1 protein is overexpressed and retains its capacity to transcriptionally activate its target genes. A specific FISH assay was developed to detect the novel MALAT1-GLI1 translocation in formalin-fixed, paraffin-embedded (FFPE) material. This resulted in the identification of two additional cases with this fusion and two cases with polysomy of the GLI1 gene. Finally, immunohistochemistry revealed that the GLI1 protein is exclusively overexpressed in those cases that harbour GLI1/12q13 genomic alterations. In conclusion, overexpression of GLI1 through a recurrent MALAT1-GLI1 translocation or GLI1 up-regulation delineates a pathogenically distinct subgroup of plexiform fibromyxomas with activation of the Sonic Hedgehog signalling pathway. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. PMID:27101025

  3. MdMYB1 Regulates Anthocyanin and Malate Accumulation by Directly Facilitating Their Transport into Vacuoles in Apples.

    PubMed

    Hu, Da-Gang; Sun, Cui-Hui; Ma, Qi-Jun; You, Chun-Xiang; Cheng, Lailiang; Hao, Yu-Jin

    2016-03-01

    Tonoplast transporters, including proton pumps and secondary transporters, are essential for plant cell function and for quality formation of fleshy fruits and ornamentals. Vacuolar transport of anthocyanins, malate, and other metabolites is directly or indirectly dependent on the H(+)-pumping activities of vacuolar H(+)-ATPase (VHA) and/or vacuolar H(+)-pyrophosphatase, but how these proton pumps are regulated in modulating vacuolar transport is largely unknown. Here, we report a transcription factor, MdMYB1, in apples that binds to the promoters of two genes encoding the B subunits of VHA, MdVHA-B1 and MdVHA-B2, to transcriptionally activate its expression, thereby enhancing VHA activity. A series of transgenic analyses in apples demonstrates that MdMYB1/10 controls cell pH and anthocyanin accumulation partially by regulating MdVHA-B1 and MdVHA-B2. Furthermore, several other direct target genes of MdMYB10 are identified, including MdVHA-E2, MdVHP1, MdMATE-LIKE1, and MdtDT, which are involved in H(+)-pumping or in the transport of anthocyanins and malates into vacuoles. Finally, we show that the mechanism by which MYB controls malate and anthocyanin accumulation in apples also operates in Arabidopsis (Arabidopsis thaliana). These findings provide novel insights into how MYB transcription factors directly modulate the vacuolar transport system in addition to anthocyanin biosynthesis, consequently controlling organ coloration and cell pH in plants. PMID:26637549

  4. Recurrent MALAT1-GLI1 oncogenic fusion and GLI1 up-regulation define a subset of plexiform fibromyxoma.

    PubMed

    Spans, Lien; Fletcher, Christopher Dm; Antonescu, Cristina R; Rouquette, Alexandre; Coindre, Jean-Michel; Sciot, Raf; Debiec-Rychter, Maria

    2016-07-01

    Plexiform fibromyxomas are rare neoplasms, being officially recognized as a distinct entity among benign mesenchymal gastric tumours in the 2010 WHO Classification of Tumours of the Digestive System. Characteristically, these tumours have a multinodular/plexiform growth pattern, and histologically contain variably cellular areas of bland myofibroblastic-type spindle cells embedded in an abundant myxoid matrix, rich in capillary-type vessels. As yet, the molecular and/or genetic features of these tumours are unknown. Here we describe a recurrent translocation, t(11;12)(q11;q13), involving the long non-coding gene metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and the gene glioma-associated oncogene homologue 1 (GLI1) in a subgroup of these tumours. The presence of the fusion transcript in our index case was confirmed using polymerase chain reaction (PCR) on genomic DNA, followed by Sanger sequencing. We showed that the truncated GLI1 protein is overexpressed and retains its capacity to transcriptionally activate its target genes. A specific FISH assay was developed to detect the novel MALAT1-GLI1 translocation in formalin-fixed, paraffin-embedded (FFPE) material. This resulted in the identification of two additional cases with this fusion and two cases with polysomy of the GLI1 gene. Finally, immunohistochemistry revealed that the GLI1 protein is exclusively overexpressed in those cases that harbour GLI1/12q13 genomic alterations. In conclusion, overexpression of GLI1 through a recurrent MALAT1-GLI1 translocation or GLI1 up-regulation delineates a pathogenically distinct subgroup of plexiform fibromyxomas with activation of the Sonic Hedgehog signalling pathway. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  5. Formation of triple-helical structures by the 3'-end sequences of MALAT1 and MENβ noncoding RNAs.

    PubMed

    Brown, Jessica A; Valenstein, Max L; Yario, Therese A; Tycowski, Kazimierz T; Steitz, Joan A

    2012-11-20

    Stability of the long noncoding-polyadenylated nuclear (PAN) RNA from Kaposi's sarcoma-associated herpesvirus is conferred by an expression and nuclear retention element (ENE). The ENE protects PAN RNA from a rapid deadenylation-dependent decay pathway via formation of a triple helix between the U-rich internal loop of the ENE and the 3'-poly(A) tail. Because viruses borrow molecular mechanisms from their hosts, we searched highly abundant human long-noncoding RNAs and identified putative ENE-like structures in metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and multiple endocrine neoplasia-β (MENβ) RNAs. Unlike the PAN ENE, the U-rich internal loops of both predicted cellular ENEs are interrupted by G and C nucleotides and reside upstream of genomically encoded A-rich tracts. We confirmed the ability of MALAT1 and MENβ sequences containing the predicted ENE and A-rich tract to increase the levels of an intronless β-globin reporter RNA. UV thermal denaturation profiles at different pH values support formation of a triple-helical structure composed of multiple U•A-U base triples and a single C•G-C base triple. Additional analyses of the MALAT1 ENE revealed that robust stabilization activity requires an intact triple helix, strong stems at the duplex-triplex junctions, a G-C base pair flanking the triplex to mediate potential A-minor interactions, and the 3'-terminal A of the A-rich tract to form a blunt-ended triplex lacking unpaired nucleotides at the duplex-triplex junction. These examples of triple-helical, ENE-like structures in cellular noncoding RNAs, are unique.

  6. Characterization of a cytosolic malate dehydrogenase cDNA which encodes an isozyme toward oxaloacetate reduction in wheat.

    PubMed

    Ding, Yu; Ma, Qing-Hu

    2004-08-01

    Malate dehydrogenase (MDH), which is ubiquitous in nature, catalyzes the interconversion of oxaloacetate and malate. Higher plants contain multiple forms of MDH that differ in co-enzyme specificity, subcellular localization and physiological function. Cytosolic NAD-dependent MDH (cyMDH) is one class of MDH that has not been extensively characterized in plants. Here we report the cloning of a cDNA from wheat by RT-PCR and cDNA library screening, which is designated as TaMDH. Sequence analysis indicated that TaMDH exhibits a highly similarity to other plant cyMDHs. Immunological analysis confirmed that TaMDH encoded a cytosolic NAD-dependent MDH. The secondary and three-dimensional structures of TaMDH were analyzed by molecular modeling. DNA gel-blot analyses demonstrated that TaMDH gene exists as two copies in the wheat genome. RNA and protein gel-blot hybridization indicated that both TaMDH mRNA and protein were constitutively expressed in vegetative tissues of wheat, with slightly lower levels in roots than in leaves and stems. In silico analysis indicated that TaMDH was also expressed in various reproductive tissues and tissues under many different stress conditions. Kinetic analysis of bacterially expressed and purified protein confirmed that TaMDH catalyzed a reaction driven towards malate synthesis, which is consistent with other cyMDHs. Evolutionary analysis showed that this class of genes evolved from a very ancestral gene. The cyMDH represents an ancestral form of MDH, which is highly conserved in plants, animals and bacteria. This implies that cyMDHs are housekeeping genes and may have very essential functions in plant metabolism.

  7. Inhibition of ruminal microbial methane production by beta-cyclodextrin iodopropane, malate and their combination in vitro.

    PubMed

    Mohammed, N; Lila, Z A; Ajisaka, N; Hara, K; Mikuni, K; Hara, K; Kanda, S; Itabashi, H

    2004-06-01

    The objective of this study was to evaluate the effects of different concentrations of l-malate (0, 5, 10 and 20 mm), 2-iodopropane-beta-cyclodextrin complex (CD-IP) (0, 0.1, 0.2 and 0.4 mm) and a combination of malate (10 and 20 mm) plus CD-IP (0.2 and 0.4 mm) on methane production from corn starch. Ruminal fluid was collected from dairy cows, mixed with phosphate buffer (1 : 2) and incubated (30 ml) anaerobically at 38 degrees C for 6 h with or without additives. Fermentation of corn starch in the presence of malate resulted in an increase (p < 0.05) in pH of the medium, total volatile fatty acid (VFA), total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were unchanged. Methane production was decreased (p < 0.05) (15.5 to 20.4%). Addition of CD-IP in corn starch resulted in an increase (p < 0.05) in total VFA and molar proportion of propionate. Acetate, pH and ammonia-N concentration of the medium were decreased (p < 0.05). Total gas production was unchanged. Methane production was decreased (p < 0.05) (25.2 to 97.1%) and hydrogen production was increased (p < 0.05). Addition of l-malate to CD-IP resulted in an increase (p < 0.05) in total VFA, total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were decreased (p < 0.05). No effects were observed on medium pH. Methane production was decreased (p < 0.05) (49.5 to 97.1%). Hydrogen production was also decreased (p < 0.05) (54.5 to 64.1%) compared with those of CD-IP alone. Therefore, these additives may be used as supplements to inhibit methane production as well as to improve rumen fermentation and animal performance.

  8. [Functional difference of malate-aspartate shuttle system in liver between plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae)].

    PubMed

    Zhu, Rui-Juan; Rao, Xin-Feng; Wei, Deng-Bang; Wang, Duo-Wei; Wei, Lian; Sun, Sheng-Zhen

    2012-04-25

    To explore the adaptive mechanisms of plateau zokor (Myospalax baileyi) to the enduring digging activity in the hypoxic environment and of plateau pika (Ochotona curzoniae) to the sprint running activity, the functional differences of malate-aspartate shuttle system (MA) in liver of plateau zokor and plateau pika were studied. The ratio of liver weight to body weight, the parameters of mitochondria in hepatocyte and the contents of lactic acid in serum were measured; the open reading frame of cytoplasmic malate dehydrogenase (MDH1), mitochondrial malate dehydrogenase (MDH2), and the partial sequence of aspartate glutamate carrier (AGC) and oxoglutarate malate carrier (OMC) genes were cloned and sequenced; MDH1, MDH2, AGC and OMC mRNA levels were determined by real-time PCR; the specific activities of MDH1 and MDH2 in liver of plateau zokor and plateau pika were measured using enzymatic methods. The results showed that, (1) the ratio of liver weight to body weight, the number and the specific surface of mitochondria in hepatocyte of plateau zokor were markedly higher than those of plateau pika (P < 0.01 or P < 0.05), but the content of lactic acid in serum of plateau pika was significantly higher than that of plateau zokor (P < 0.01); (2) MDH1 and MDH2 mRNA levels as well as their enzymatic activities in liver of plateau zokor were significantly higher than those of plateau pika (P < 0.01 or 0.05), AGC mRNA level of the zokor was significantly higher than that of the pika (P < 0.01), while no difference was found at OMC mRNA level between them (P > 0.05); (3) mRNA level and enzymatic activity of MDH1 was significantly lower than those of MDH2 in the pika liver (P < 0.01), MDH1 mRNA level of plateau zokor was markedly higher than that of MDH2 (P < 0.01), but the activities had no difference between MDH1 and MDH2 in liver of the zokor (P > 0.05). These results indicate that the plateau zokor obtains ATP in the enduring digging activity by enhancing the function of MA

  9. Activity of citrulline malate on acid-base balance and blood ammonia and amino acid levels. Study in the animal and in man.

    PubMed

    Callis, A; Magnan de Bornier, B; Serrano, J J; Bellet, H; Saumade, R

    1991-06-01

    An experimental evaluation of citrulline malate (Stimol, CAS 54940-97-5), an anti-fatigue compound, was undertaken in man and in the animal in order to study the pharmacological activity of the substance at hepatic and renal level. In man, the protocol involved a double-blind randomized, placebo-controlled cross-over technique. The study in the animal was blind and placebo-controlled with two randomized parallel groups. Results showed that citrulline malate stimulates hepatic ureogenesis and favorizes the renal reabsorption of bicarbonates. These metabolic actions had a protective effect against acidosis and ammonia poisoning and explain the anti-fatigue properties of citrulline malate in man. PMID:1930358

  10. Phosphofructokinase and malate dehydrogenase participate in the in vitro maturation of porcine oocytes.

    PubMed

    Breininger, E; Vecchi Galenda, B E; Alvarez, G M; Gutnisky, C; Cetica, P D

    2014-12-01

    Oocyte maturation depends on the metabolic activity of cumulus-oocyte complex (COC) that performs nutritive and regulatory functions during this process. In this work, the enzymes [phosphofructokinase (PFK) and malate dehydrogenase (MDH)] were tested to elucidate the metabolic profile of porcine COCs during the in vitro maturation (IVM). Enzymatic activity was expressed in U/COC and U/mg protein (specific activity) as mean ± SEM. In vitro maturation was performed with 2-oxoglutarate (5, 10 and 20 mm) or hydroxymalonate (30, 60 and 100 mm) inhibitors of PFK and MDH, respectively. The PFK and MDH activities (U) remained constant during maturation. For PFK, the U were (2.48 ± 0.23) 10(-5) and (2.54 ± 0.32) 10(-5) , and for MDH, the U were (4.72 ± 0.42) 10(-5) and (4.38 ± 0.25) 10(-5) for immature and in vitro matured COCs, respectively. The specific activities were significantly lower after IVM, for PFK (4.29 ± 0.48) 10(-3) and (0.94 ± 0.12) 10(-3) , and for MDH (9.08 ± 0.93) 10(-3) and (1.89 ± 0.10) 10(-3) for immature and in vitro matured COCs, respectively. In vitro maturation percentages and enzymatic activity diminished with 20 mm 2-oxoglutarate or 60 mm hydroxymalonate (p < 0.05). Viability was not affected by any concentration of the inhibitors evaluated. The U remained unchanged during IVM; however, the increase in the total protein content per COC provoked a decrease in the specific activity of both enzymes. Phosphofructokinase and MDH necessary for oocyte IVM would be already present in the immature oocyte. The presence of inhibitors of these enzymes impairs the meiotic maturation. Therefore, the participation of these enzymes in the energy metabolism of the porcine oocyte during IVM is confirmed in this study.

  11. The lncRNA MALAT1, acting through HIF-1α stabilization, enhances arsenite-induced glycolysis in human hepatic L-02 cells.

    PubMed

    Luo, Fei; Liu, Xinlu; Ling, Min; Lu, Lu; Shi, Le; Lu, Xiaolin; Li, Jun; Zhang, Aihua; Liu, Qizhan

    2016-09-01

    Accelerated glycolysis, a common process in tumor cells called the Warburg effect, is associated with various biological phenomena. However, the role of glycolysis induced by arsenite, a well-established human carcinogen, is unknown. Long non-coding RNAs (lncRNAs) act as regulators in various cancers, but how lncRNAs regulate glucose metabolism remains largely unexplored. We have found that, in human hepatic epithelial (L-02) cells, arsenite increases lactate production; glucose consumption; and expression of glycolysis-related genes, including HK-2, Eno-1, and Glut-4. In L-02 cells exposed to arsenite, the lncRNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and hypoxia inducible factors (HIFs)-α, the transcriptional regulators of cellular response to hypoxia, are over-expressed. In addition, HIF-1α, not HIF-2α, is involved in arsenite-induced glycolysis, and MALAT1 enhances arsenite-induced glycolysis. Although MALAT1 regulates HIF-α and promotes arsenite-induced glycolysis, MALAT1 promotes glycolysis through HIF-1α, not HIF-2α. Moreover, arsenite-increased MALAT1 enhances the disassociation of Von Hippel-Lindau (VHL) tumor suppressor from HIF-1α, alleviating VHL-mediated ubiquitination of HIF-1α, which causes accumulation of HIF-1α. In sum, these findings indicate that MALAT1, acting through HIF-1α stabilization, is a mediator that enhances glycolysis induced by arsenite. These results provide a link between the induction of lncRNAs and the glycolysis in cells exposed to arsenite, and thus establish a previously unknown mechanism for arsenite-induced hepatotoxicity.

  12. Plant sunscreens in the UV-B: ultraviolet spectroscopy of jet-cooled sinapoyl malate, sinapic acid, and sinapate ester derivatives.

    PubMed

    Dean, Jacob C; Kusaka, Ryoji; Walsh, Patrick S; Allais, Florent; Zwier, Timothy S

    2014-10-22

    Ultraviolet spectroscopy of sinapoyl malate, an essential UV-B screening agent in plants, was carried out in the cold, isolated environment of a supersonic expansion to explore its intrinsic UV spectral properties in detail. Despite these conditions, sinapoyl malate displays anomalous spectral broadening extending well over 1000 cm(-1) in the UV-B region, presenting the tantalizing prospect that nature's selection of UV-B sunscreen is based in part on the inherent quantum mechanical features of its excited states. Jet-cooling provides an ideal setting in which to explore this topic, where complications from intermolecular interactions are eliminated. In order to better understand the structural causes of this behavior, the UV spectroscopy of a series of sinapate esters was undertaken and compared with ab initio calculations, starting with the simplest sinapate chromophore sinapic acid, and building up the ester side chain to sinapoyl malate. This "deconstruction" approach provided insight into the active mechanism intrinsic to sinapoyl malate, which is tentatively attributed to mixing of the bright V ((1)ππ*) state with an adiabatically lower (1)nπ* state which, according to calculations, shows unique charge-transfer characteristics brought on by the electron-rich malate side chain. All members of the series absorb strongly in the UV-B region, but significant differences emerge in the appearance of the spectrum among the series, with derivatives most closely associated with sinapoyl malate showing characteristic broadening even under jet-cooled conditions. The long vibronic progressions, conformational distribution, and large oscillator strength of the V (ππ*) transition in sinapates makes them ideal candidates for their role as UV-B screening agents in plants.

  13. The lncRNA MALAT1, acting through HIF-1α stabilization, enhances arsenite-induced glycolysis in human hepatic L-02 cells.

    PubMed

    Luo, Fei; Liu, Xinlu; Ling, Min; Lu, Lu; Shi, Le; Lu, Xiaolin; Li, Jun; Zhang, Aihua; Liu, Qizhan

    2016-09-01

    Accelerated glycolysis, a common process in tumor cells called the Warburg effect, is associated with various biological phenomena. However, the role of glycolysis induced by arsenite, a well-established human carcinogen, is unknown. Long non-coding RNAs (lncRNAs) act as regulators in various cancers, but how lncRNAs regulate glucose metabolism remains largely unexplored. We have found that, in human hepatic epithelial (L-02) cells, arsenite increases lactate production; glucose consumption; and expression of glycolysis-related genes, including HK-2, Eno-1, and Glut-4. In L-02 cells exposed to arsenite, the lncRNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and hypoxia inducible factors (HIFs)-α, the transcriptional regulators of cellular response to hypoxia, are over-expressed. In addition, HIF-1α, not HIF-2α, is involved in arsenite-induced glycolysis, and MALAT1 enhances arsenite-induced glycolysis. Although MALAT1 regulates HIF-α and promotes arsenite-induced glycolysis, MALAT1 promotes glycolysis through HIF-1α, not HIF-2α. Moreover, arsenite-increased MALAT1 enhances the disassociation of Von Hippel-Lindau (VHL) tumor suppressor from HIF-1α, alleviating VHL-mediated ubiquitination of HIF-1α, which causes accumulation of HIF-1α. In sum, these findings indicate that MALAT1, acting through HIF-1α stabilization, is a mediator that enhances glycolysis induced by arsenite. These results provide a link between the induction of lncRNAs and the glycolysis in cells exposed to arsenite, and thus establish a previously unknown mechanism for arsenite-induced hepatotoxicity. PMID:27287256

  14. Plant sunscreens in the UV-B: ultraviolet spectroscopy of jet-cooled sinapoyl malate, sinapic acid, and sinapate ester derivatives.

    PubMed

    Dean, Jacob C; Kusaka, Ryoji; Walsh, Patrick S; Allais, Florent; Zwier, Timothy S

    2014-10-22

    Ultraviolet spectroscopy of sinapoyl malate, an essential UV-B screening agent in plants, was carried out in the cold, isolated environment of a supersonic expansion to explore its intrinsic UV spectral properties in detail. Despite these conditions, sinapoyl malate displays anomalous spectral broadening extending well over 1000 cm(-1) in the UV-B region, presenting the tantalizing prospect that nature's selection of UV-B sunscreen is based in part on the inherent quantum mechanical features of its excited states. Jet-cooling provides an ideal setting in which to explore this topic, where complications from intermolecular interactions are eliminated. In order to better understand the structural causes of this behavior, the UV spectroscopy of a series of sinapate esters was undertaken and compared with ab initio calculations, starting with the simplest sinapate chromophore sinapic acid, and building up the ester side chain to sinapoyl malate. This "deconstruction" approach provided insight into the active mechanism intrinsic to sinapoyl malate, which is tentatively attributed to mixing of the bright V ((1)ππ*) state with an adiabatically lower (1)nπ* state which, according to calculations, shows unique charge-transfer characteristics brought on by the electron-rich malate side chain. All members of the series absorb strongly in the UV-B region, but significant differences emerge in the appearance of the spectrum among the series, with derivatives most closely associated with sinapoyl malate showing characteristic broadening even under jet-cooled conditions. The long vibronic progressions, conformational distribution, and large oscillator strength of the V (ππ*) transition in sinapates makes them ideal candidates for their role as UV-B screening agents in plants. PMID:25295994

  15. Metabolic regulation of phytoplasma malic enzyme and phosphotransacetylase supports the use of malate as an energy source in these plant pathogens.

    PubMed

    Saigo, Mariana; Golic, Adrián; Alvarez, Clarisa E; Andreo, Carlos S; Hogenhout, Saskia A; Mussi, María A; Drincovich, María F

    2014-12-01

    Phytoplasmas ('Candidatus Phytoplasma') are insect-vectored plant pathogens. The genomes of these bacteria are small with limited metabolic capacities making them dependent on their plant and insect hosts for survival. In contrast to mycoplasmas and other relatives in the class Mollicutes, phytoplasmas encode genes for malate transporters and malic enzyme (ME) for conversion of malate into pyruvate. It was hypothesized that malate is probably a major energy source for phytoplasmas as these bacteria are limited in the uptake and processing of carbohydrates. In this study, we investigated the metabolic capabilities of 'Candidatus (Ca.) phytoplasma' aster yellows witches'-broom (AYWB) malic enzyme (ME). We found that AYWB-ME has malate oxidative decarboxylation activity, being able to convert malate to pyruvate and CO2 with the reduction of either NAD or NADP, and displays distinctive kinetic mechanisms depending on the relative concentration of the substrates. AYWB-ME activity was strictly modulated by the ATP/ADP ratio, a feature which has not been found in other ME isoforms characterized to date. In addition, we found that the 'Ca. Phytoplasma' AYWB PduL-like enzyme (AYWB-PduL) harbours phosphotransacetylase activity, being able to convert acetyl-CoA to acetyl phosphate downstream of pyruvate. ATP also inhibited AYWB-PduL activity, as with AYWB-ME, and the product of the reaction catalysed by AYWB-PduL, acetyl phosphate, stimulated AYWB-ME activity. Overall, our data indicate that AYWB-ME and AYWB-PduL activities are finely coordinated by common metabolic signals, like ATP/ADP ratios and acetyl phosphate, which support their participation in energy (ATP) and reducing power [NAD(P)H] generation from malate in phytoplasmas.

  16. Oxaloacetate and malate production in engineered Escherichia coli by expression of codon-optimized phosphoenolpyruvate carboxylase2 gene from Dunaliella salina.

    PubMed

    Park, Soohyun; Chang, Kwang Suk; Jin, Eonseon; Pack, Seung Pil; Lee, Jinwon

    2013-01-01

    A new phosphoenolpyruvate carboxylase (PEPC) gene of Dunaliella salina is identified using homology analysis was conducted using PEPC gene of Chlamydomonas reinhardtii and Arabidopsis thaliana. Recombinant E. coli SGJS115 with increased production of malate and oxaloacetate was developed by introducing codon-optimized phosphoenolpyruvate carboxylase2 (OPDSPEPC2) gene of Dunaliella salina. E. coli SGJS115 yielded a 9.9 % increase in malate production. In addition, E. coli SGJS115 exhibited two times increase in the yield of oxaloacetate over the E. coli SGJS114 having identified PEPC2 gene obtained from Dunaliella salina.

  17. A new technique for the precise location of lactate and malate dehydrogenases in goat, boar and water buffalo spermatozoa using gel incubation film.

    PubMed

    Kohsaka, T; Takahara, H; Tagami, S; Sasada, H; Masaki, J

    1992-05-01

    Gel incubation film, which contained gelatin to prevent the diffusion of enzyme during chemical reaction and phenazine methosulfate to operate as a hydrogen acceptor between NADH and tetrazolium, was used and light microscopy revealed that lactate dehydrogenase was located in the head and tail of the spermatozoa as well as in the midpiece, whereas malate dehydrogenase was confined to the midpiece in spermatozoa of the animals examined. In goat spermatozoa, lactate dehydrogenase was associated mainly with the inner acrosomal membrane in the head, the mitochondrial matrix in the midpiece and with flagellar fibrils in the tail, whereas malate dehydrogenase was present only in the mitochondrial matrix.

  18. Enhanced photosynthetic performance and growth as a consequence of decreasing mitochondrial malate dehydrogenase activity in transgenic tomato plants.

    PubMed

    Nunes-Nesi, Adriano; Carrari, Fernando; Lytovchenko, Anna; Smith, Anna M O; Loureiro, Marcelo Ehlers; Ratcliffe, R George; Sweetlove, Lee J; Fernie, Alisdair R

    2005-02-01

    Transgenic tomato (Solanum lycopersicum) plants expressing a fragment of the mitochondrial malate dehydrogenase gene in the antisense orientation and exhibiting reduced activity of this isoform of malate dehydrogenase show enhanced photosynthetic activity and aerial growth under atmospheric conditions (360 ppm CO2). In comparison to wild-type plants, carbon dioxide assimilation rates and total plant dry matter were up to 11% and 19% enhanced in the transgenics, when assessed on a whole-plant basis. Accumulation of carbohydrates and redox-related compounds such as ascorbate was also markedly elevated in the transgenics. Also increased in the transgenic plants was the capacity to use L-galactono-lactone, the terminal precursor of ascorbate biosynthesis, as a respiratory substrate. Experiments in which ascorbate was fed to isolated leaf discs also resulted in increased rates of photosynthesis providing strong indication for an ascorbate-mediated link between the energy-generating processes of respiration and photosynthesis. This report thus shows that the repression of this mitochondrially localized enzyme improves both carbon assimilation and aerial growth in a crop species. PMID:15665243

  19. Enzyme:nanoparticle bioconjugates with two sequential enzymes: stoichiometry and activity of malate dehydrogenase and citrate synthase on Au nanoparticles.

    PubMed

    Keighron, Jacqueline D; Keating, Christine D

    2010-12-21

    We report the synthesis and characterization of bioconjugates in which the enzymes malate dehydrogenase (MDH) and/or citrate synthase (CS) were adsorbed to 30 nm diameter Au nanoparticles. Enzyme:Au stoichiometry and kinetic parameters (specific activity, k(cat), K(M), and activity per particle) were determined for MDH:Au, CS:Au, and three types of dual-activity MDH/CS:Au bioconjugates. For single-activity bioconjugates (MDH:Au and CS:Au), the number of enzyme molecules adsorbed per particle was dependent upon the enzyme concentration in solution, with multilayers forming at high enzyme:Au solution ratios. The specific activity of adsorbed enzyme increased with increasing number adsorbed per particle for CS:Au, but was less sensitive to stoichiometry for MDH:Au. Dual activity bioconjugates were prepared in three ways: (1) by adsorption of MDH followed by CS, (2) by adsorption of CS followed by MDH, and (3) by coadsorption of both enzymes from the same solution. The resulting bioconjugates differed substantially in the number of enzyme molecules adsorbed per particle, the specific activity of the adsorbed enzymes, and also the enzymatic activity per particle. Bioconjugates formed by adding CS to the Au nanoparticles before MDH was added exhibited higher specific activities for both enzymes than those formed by adding the enzymes in the reverse order. These bioconjugates also had 3-fold higher per-particle sequential activity for conversion of malate to citrate, despite substantially fewer copies of both enzymes present.

  20. Posttranscriptional silencing of the lncRNA MALAT1 by miR-217 inhibits the epithelial-mesenchymal transition via enhancer of zeste homolog 2 in the malignant transformation of HBE cells induced by cigarette smoke extract.

    PubMed

    Lu, Lu; Luo, Fei; Liu, Yi; Liu, Xinlu; Shi, Le; Lu, Xiaolin; Liu, Qizhan

    2015-12-01

    Lung cancer is regarded as the leading cause of cancer-related deaths, and cigarette smoking is one of the strongest risk factors for the development of lung cancer. However, the mechanisms for cigarette smoke-induced lung carcinogenesis remain unclear. The present study investigated the effects of an miRNA (miR-217) on levels of an lncRNA (MALAT1) and examined the role of these factors in the epithelial-mesenchymal transition (EMT) induced by cigarette smoke extract (CSE) in human bronchial epithelial (HBE) cells. In these cells, CSE caused decreases of miR-217 levels and increases in lncRNA MALAT1 levels. Over-expression of miR-217 with a mimic attenuated the CSE-induced increase of MALAT1 levels, and reduction of miR-217 levels by an inhibitor enhanced expression of MALAT1. Moreover, the CSE-induced increase of MALAT1 expression was blocked by an miR-217 mimic, indicating that miR-217 negatively regulates MALAT1 expression. Knockdown of MALAT1 reversed CSE-induced increases of EZH2 (enhancer of zeste homolog 2) and H3K27me3 levels. In addition to the alteration from epithelial to spindle-like mesenchymal morphology, chronic exposure of HBE cells to CSE increased the levels of EZH2, H3K27me3, vimentin, and N-cadherin and decreased E-cadherin levels, effects that were reversed by MALAT1 siRNA or EZH2 siRNA. The results indicate that miR-217 regulation of EZH2/H3K27me3 via MALAT1 is involved in CSE-induced EMT and malignant transformation of HBE cells. The posttranscriptional silencing of MALAT1 by miR-217 provides a link, through EZH2, between ncRNAs and the EMT and establishes a mechanism for CSE-induced lung carcinogenesis.

  1. Effects of the dicarboxylic acids malate and fumarate on E. coli 0157:H7 and Salmonella enterica Typhimurium populations in pure culture and in mixed ruminal microorganism fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dicarboxylic organic acids malate and fumarate increase ruminal pH, reduce methane production, increase propionate and total VFA production, and reduce lactic acid accumulation in a manner similar to ionophores. These acids stimulate the ruminal bacterium Selenomonas ruminantium to ferment lact...

  2. Cancer–Osteoblast Interaction Reduces Sost Expression in Osteoblasts and Up-Regulates lncRNA MALAT1 in Prostate Cancer

    PubMed Central

    Sebastian, Aimy; Hum, Nicholas R.; Hudson, Bryan D.; Loots, Gabriela G.

    2015-01-01

    Dynamic interaction between prostate cancer and the bone microenvironment is a major contributor to metastasis of prostate cancer to bone. In this study, we utilized an in vitro co-culture model of PC3 prostate cancer cells and osteoblasts followed by microarray based gene expression profiling to identify previously unrecognized prostate cancer–bone microenvironment interactions. Factors secreted by PC3 cells resulted in the up-regulation of many genes in osteoblasts associated with bone metabolism and cancer metastasis, including Mmp13, Il-6 and Tgfb2, and down-regulation of Wnt inhibitor Sost. To determine whether altered Sost expression in the bone microenvironment has an effect on prostate cancer metastasis, we co-cultured PC3 cells with Sost knockout (SostKO) osteoblasts and wildtype (WT) osteoblasts and identified several genes differentially regulated between PC3-SostKO osteoblast co-cultures and PC3-WT osteoblast co-cultures. Co-culturing PC3 cells with WT osteoblasts up-regulated cancer-associated long noncoding RNA (lncRNA) MALAT1 in PC3 cells. MALAT1 expression was further enhanced when PC3 cells were co-cultured with SostKO osteoblasts and treatment with recombinant Sost down-regulated MALAT1 expression in these cells. Our results suggest that reduced Sost expression in the tumor microenvironment may promote bone metastasis by up-regulating MALAT1 in prostate cancer. PMID:27600237

  3. Mitochondrial malate dehydrogenase and malic enzyme of a filarial worm Setaria digitata: some properties and effects of drugs and herbal extracts.

    PubMed

    Banu, M J; Nellaiappan, K; Dhandayuthapani, S

    1992-06-01

    Mitochondrial malate dehydrogenase (mMDH) and malic enzyme (mME) of a filarial worm Setaria digitata were studied. mMDH exhibited the highest activities in the oxidation and reduction reactions at pH 9.5 and pH 6.2, respectively, while mME did so in the malate decarboxylation reaction at pH 6.8. mME showed no detectable activity on the pyruvate carboxylation direction. The Km values for malate (1.7 mM) and oxaloacetate (0.17 mM) and the ratio of Vmax oxidation: Vmax reduction (2.73) tend to favor the oxaloacetate reduction by mMDH. mME showed a relatively high Km value of 8.3 mM, for malate decarboxylation. A drug, diethylcarbamazine citrate (DEC-C), did not change appreciably the activity of either mMDH or mME, while filarin (a drug of herbal origin) effectively inhibited mMDH. The leaf extracts of Ocimum sanctum, Lawsonia inermis and Calotropis gigantea and leaf and flower extracts of Azadirachta indica were, however, found to inhibit both mMDH and mME.

  4. Independent fluctuations of malate and citrate in the CAM species Clusia hilariana Schltdl. under low light and high light in relation to photoprotection.

    PubMed

    Miszalski, Zbigniew; Kornas, Andrzej; Rozpądek, Piotr; Fischer-Schliebs, Elke; Lüttge, Ulrich

    2013-03-15

    Clusia hilariana Schltdl. is described in literature as an obligate Crassulacean acid metabolism (CAM) species. In the present study we assessed the effect of irradiance with low light (LL, 200μmolm(-2)s(-1)) and high light (HL, 650-740μmolm(-2)s(-1)), on the interdependency of citrate and malate diurnal fluctuations. In plants grown at HL CAM-type oscillations of concentration of citrate and malate were obvious. However, at LL daily courses of both acids do not seem to indicate efficient utilization of these compounds as CO2 and NADPH sources. One week after transferring plants from LL to HL decarboxylation of malate was accelerated. Thus, in the CAM plant C. hilariana two independent rhythms of accumulation and decarboxylation of malate and citrate take place, which appear to be related to photosynthesis and respiration, respectively. Non photochemical quenching (NPQ) of photosystem II, especially well expressed during the evening hours was enhanced. Exposure to HL for 7 d activated oxidative stress protection mechanisms such as the interconversion of violaxanthin (V), antheraxanthin (A) and zeaxanthin (Z) (epoxydation/de-epoxydation) measured as epoxydation state (EPS). This was accompanied by a slight increase in the total amount of these pigments. However, all these changes were not observed in plants exposed to HL for only 2 d. Besides violaxanthin cycle components also lutein, which shows a small, but not significant increase, may be involved in dissipating excess light energy in C. hilariana.

  5. Functional, structural and phylogenetic analysis of domains underlying the Al-sensitivity of the aluminium-activated malate/anion transporter, TaALMT1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    TaALMT1 (Triticum aestivum Aluminum Activated Malate Transporter) is the founding member of a novel gene family of anion transporters (ALMTs) that mediate the efflux of organic acids. A small subgroup of root-localized ALMTs, including TaALMT1, is physiologically associated with in planta aluminum (...

  6. Cancer–Osteoblast Interaction Reduces Sost Expression in Osteoblasts and Up-Regulates lncRNA MALAT1 in Prostate Cancer

    PubMed Central

    Sebastian, Aimy; Hum, Nicholas R.; Hudson, Bryan D.; Loots, Gabriela G.

    2015-01-01

    Dynamic interaction between prostate cancer and the bone microenvironment is a major contributor to metastasis of prostate cancer to bone. In this study, we utilized an in vitro co-culture model of PC3 prostate cancer cells and osteoblasts followed by microarray based gene expression profiling to identify previously unrecognized prostate cancer–bone microenvironment interactions. Factors secreted by PC3 cells resulted in the up-regulation of many genes in osteoblasts associated with bone metabolism and cancer metastasis, including Mmp13, Il-6 and Tgfb2, and down-regulation of Wnt inhibitor Sost. To determine whether altered Sost expression in the bone microenvironment has an effect on prostate cancer metastasis, we co-cultured PC3 cells with Sost knockout (SostKO) osteoblasts and wildtype (WT) osteoblasts and identified several genes differentially regulated between PC3-SostKO osteoblast co-cultures and PC3-WT osteoblast co-cultures. Co-culturing PC3 cells with WT osteoblasts up-regulated cancer-associated long noncoding RNA (lncRNA) MALAT1 in PC3 cells. MALAT1 expression was further enhanced when PC3 cells were co-cultured with SostKO osteoblasts and treatment with recombinant Sost down-regulated MALAT1 expression in these cells. Our results suggest that reduced Sost expression in the tumor microenvironment may promote bone metastasis by up-regulating MALAT1 in prostate cancer.

  7. Phosphorylation at S384 regulates the activity of the TaALMT1 malate transporter that underlies aluminum resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study we examined the role of protein phosphorylation & dephosphorylation in the transport properties of the wheat root malate efflux transporter underlying Al resistance, TaALMT1. Preincubation of Xenopus laevis oocytes expressing TaALMT1 with protein kinase inhibitors (K252a and staurospo...

  8. The Long Noncoding RNA MALAT-1 is A Novel Biomarker in Various Cancers: A Meta-analysis Based on the GEO Database and Literature

    PubMed Central

    Wang, Yumin; Xue, Dan; Li, Yuwei; Pan, Xuya; Zhang, Xueying; Kuang, Biao; Zhou, Ming; Li, Xiaoling; Xiong, Wei; Li, Guiyuan; Zeng, Zhaoyang; Yang, Tubao

    2016-01-01

    Background: MALAT-1 is significantly overexpressed in various cancers, suggesting that it might be a potential biomarker of cancer. Methods: A meta-analysis was performed using microarray data obtained via the Affymetrix Human Genome U133 Plus 2.0 platform found in the Gene Expression Omnibus (GEO) database and data obtained through a systematic search of PubMed and Web of Science. The pooled odds ratio (OR) and hazard ratio (HR) with 95% CI (Confidence interval) were used to judge the value of biomarkers. Results: A total of 28 studies were included in this meta-analysis, comprising a total of 3573 patients. MALAT-1 was significantly linked with over survival (OS) (HR=1.58, 95%CI: 1.12-2.23), recurrence-free survival (RFS) (HR=2.32, 95% CI: 1.68-3.19) and death-free survival (DFS) (HR=3.28, 95% CI: 1.52-7.09). We found that MALAT-1 was a risk factor in the prognoses of lung cancer (HR=1.54, 95%CI: 1.01-2.34), digestive system cancer (HR=2.16, 95% CI: 1.34-3.48) and ovarian cancer (HR=3.98, 95% CI: 1.54-10.25). In contrast, MALAT-1 was a safe factor in the prognosis of B cell lineage cancer (HR=0.45, 95% CI: 0.33-0.61). MALAT-1 was also a risk factor of RFS in breast cancer (HR=1.97, 95% CI: 1.25-3.09) and the TNM stage in pancreatic cancer (OR=3.65, 95% CI: 1.86-7.18) and glioma (OR=4.30, 95% CI: 1.90-9.73) and was a safe factor in colorectal cancer (OR=0.17, 95% CI: 0.08-0.35). MALAT-1 was significantly associated with lymph node metastasis in clear cell carcinoma (OR=5.04, 95% CI: 2.36-10.78) and distant metastasis in pancreatic cancer (OR=11.64, 95% CI: 2.13-63.78). Conclusions: MALAT-1 can serve as a molecular marker in different types of cancers. PMID:27313790

  9. Properties of Succinyl-Coenzyme A:l-Malate Coenzyme A Transferase and Its Role in the Autotrophic 3-Hydroxypropionate Cycle of Chloroflexus aurantiacus

    PubMed Central

    Friedmann, Silke; Steindorf, Astrid; Alber, Birgit E.; Fuchs, Georg

    2006-01-01

    The 3-hydroxypropionate cycle has been proposed to operate as the autotrophic CO2 fixation pathway in the phototrophic bacterium Chloroflexus aurantiacus. In this pathway, acetyl coenzyme A (acetyl-CoA) and two bicarbonate molecules are converted to malate. Acetyl-CoA is regenerated from malyl-CoA by l-malyl-CoA lyase. The enzyme forming malyl-CoA, succinyl-CoA:l-malate coenzyme A transferase, was purified. Based on the N-terminal amino acid sequence of its two subunits, the corresponding genes were identified on a gene cluster which also contains the gene for l-malyl-CoA lyase, the subsequent enzyme in the pathway. Both enzymes were severalfold up-regulated under autotrophic conditions, which is in line with their proposed function in CO2 fixation. The two CoA transferase genes were cloned and heterologously expressed in Escherichia coli, and the recombinant enzyme was purified and studied. Succinyl-CoA:l-malate CoA transferase forms a large (αβ)n complex consisting of 46- and 44-kDa subunits and catalyzes the reversible reaction succinyl-CoA + l-malate → succinate + l-malyl-CoA. It is specific for succinyl-CoA as the CoA donor but accepts l-citramalate instead of l-malate as the CoA acceptor; the corresponding d-stereoisomers are not accepted. The enzyme is a member of the class III of the CoA transferase family. The demonstration of the missing CoA transferase closes the last gap in the proposed 3-hydroxypropionate cycle. PMID:16547052

  10. Changes in apoplastic pH and membrane potential in leaves in relation to stomatal responses to CO2, malate, abscisic acid or interruption of water supply.

    PubMed

    Hedrich, R; Neimanis, S; Savchenko, G; Felle, H H; Kaiser, W M; Heber, U

    2001-08-01

    Low CO2 concentrations open CO2-sensitive stomata whereas elevated CO2 levels close them. This CO2 response is maintained in the dark. To elucidate mechanisms underlying the dark CO2 response we introduced pH- and potential-sensitive dyes into the apoplast of leaves. After mounting excised leaves in a gas-exchange chamber, changes in extracellular proton concentration and transmembrane potential differences as well as transpiration and respiration were simultaneously monitored. Upon an increase in CO2 concentration transient changes in apoplastic pH (occasionally brief acidification, but always followed by alkalinization) and in membrane potential (brief hyperpolarization followed by depolarization) accompanied stomatal closure. Alkalinization and depolarization were also observed when leaves were challenged with abscisic acid or when water flow was interrupted. During stomatal opening in response to CO2-free air the apoplastic pH increased while the membrane potential initially depolarized before it transiently hyperpolarized. To examine whether changes in apoplastic malate concentrations represent a closing signal for stomata, malate was fed into the transpiration stream. Although malate caused apoplastic alkalinization and membrane depolarization reminiscent of the effects observed with CO2 and abscisic acid, this dicarboxylate closed the stomata only partially and less effectively than CO2. Apoplastic alkalinization was also observed and stomata closed partially when KCl was fed to the leaves. Respiration increased on feeding of malate or KCl, or while abscisic acid closed the stomate. From these results we conclude that CO2 signals modulate the activity of plasma-membrane ion channels and of plasmalemma H+-ATPases during changes in stomatal aperture. Responses to potassium malate and KCl are not restricted to guard cells and neighbouring cells.

  11. Evidence for a Polymorphism in Gametic Segregation Using a Malate Dehydrogenase Locus in the Tetraploid Treefrog HYLA VERSICOLOR

    PubMed Central

    Danzmann, Roy G.; Bogart, James P.

    1982-01-01

    Artificial cross combinations of tetraploid Hyla versicolor were analyzed electrophoretically using a polymorphic malate dehydrogenase locus (MDH-1) to determine the mechanism of chromosome segregation. Models for differentiating between disomic and tetrasomic inheritance are presented and tested. In some crosses progeny genotypes fit a disomic mode of segregation. In other crosses there is only evidence for a tetrasomic mode of segregation. Additional crosses produced genotypic ratios which conformed to either a disomic or tetrasomic mode of segregation. The same type of inheritance was demonstrated for any individual when used in multiple cross combinations. These results suggest that there exists in H. versicolor a polymorphism with respect to segregation of gametes, resulting from differences in chromosome pairings during meiosis I. PMID:7106558

  12. Alteration of coenzyme specificity of malate dehydrogenase from Streptomyces coelicolor A3(2) by site-directed mutagenesis.

    PubMed

    Ge, Y D; Song, P; Cao, Z Y; Wang, P; Zhu, G P

    2014-07-29

    We describe here for the first time the alteration of coenzyme specificity of malate dehydrogenase (MDH) from Streptomyces coelicolor A3(2) (ScMDH). In the present study, we replaced four amino acid residues in the Rossmann fold (βB-αC) region of NADH-dependent ScMDH by site-directed mutagenesis with those of NADPH-dependent MDH (Glu42Gly, Ile43Ser, Pro45Arg, and Ala46Ser). The coenzyme specificity of the mutant enzyme (ScMDH-T4) was examined. Coenzyme specificity of ScMDH-T4 was shifted 2231.3-fold toward NADPH using kcat/Km(coenzyme) as the measurement of coenzyme specificity. Accordingly, the effect of the replacements on coenzyme specificity is discussed. Our work provides further insight into the coenzyme specificity of ScMDH.

  13. The contribution of stored malate and citrate to the substrate requirements of metabolism of ripening peach (Prunus persica L. Batsch) flesh is negligible. Implications for the occurrence of phosphoenolpyruvate carboxykinase and gluconeogenesis.

    PubMed

    Famiani, Franco; Farinelli, Daniela; Moscatello, Stefano; Battistelli, Alberto; Leegood, Richard C; Walker, Robert P

    2016-04-01

    The first aim of this study was to determine the contribution of stored malate and citrate to the substrate requirements of metabolism in the ripening flesh of the peach (Prunus persica L. Batsch) cultivar Adriatica. In the flesh, stored malate accumulated before ripening could contribute little or nothing to the net substrate requirements of metabolism. This was because there was synthesis and not dissimilation of malate throughout ripening. Stored citrate could potentially contribute a very small amount (about 5.8%) of the substrate required by metabolism when the whole ripening period was considered, and a maximum of about 7.5% over the latter part of ripening. The second aim of this study was to investigate why phosphoenolpyruvate carboxykinase (PEPCK) an enzyme utilised in gluconeogenesis from malate and citrate is present in peach flesh. The occurrence and localisation of enzymes utilised in the metabolism of malate, citrate and amino acids were determined in peach flesh throughout its development. Phosphoenolpyruvate carboxylase (essential for the synthesis of malate and citrate) was present in the same cells and at the same time as PEPCK and NADP-malic enzyme (both utilised in the dissimilation of malate and citrate). A hypothesis is presented to explain the presence of these enzymes and to account for the likely occurrence of gluconeogenesis.

  14. Loss of Mitochondrial Malate Dehydrogenase Activity Alters Seed Metabolism Impairing Seed Maturation and Post-Germination Growth in Arabidopsis.

    PubMed

    Sew, Yun Shin; Ströher, Elke; Fenske, Ricarda; Millar, A Harvey

    2016-06-01

    Mitochondrial malate dehydrogenase (mMDH; EC 1.1.1.37) has multiple roles; the most commonly described is its catalysis of the interconversion of malate and oxaloacetate in the tricarboxylic acid cycle. The roles of mMDH in Arabidopsis (Arabidopsis thaliana) seed development and germination were investigated in mMDH1 and mMDH2 double knockout plants. A significant proportion of mmdh1mmdh2 seeds were nonviable and developed only to torpedo-shaped embryos, indicative of arrested seed embryo growth during embryogenesis. The viable mmdh1mmdh2 seeds had an impaired maturation process that led to slow germination rates as well as retarded post-germination growth, shorter root length, and decreased root biomass. During seed development, mmdh1mmdh2 showed a paler green phenotype than the wild type and exhibited deficiencies in reserve accumulation and reduced final seed biomass. The respiration rate of mmdh1mmdh2 seeds was significantly elevated throughout their maturation, consistent with the previously reported higher respiration rate in mmdh1mmdh2 leaves. Mutant seeds showed a consistently higher content of free amino acids (branched-chain amino acids, alanine, serine, glycine, proline, and threonine), differences in sugar and sugar phosphate levels, and lower content of 2-oxoglutarate. Seed-aging assays showed that quiescent mmdh1mmdh2 seeds lost viability more than 3 times faster than wild-type seeds. Together, these data show the important role of mMDH in the earliest phases of the life cycle of Arabidopsis.

  15. Reduced mitochondrial malate dehydrogenase activity has a strong effect on photorespiratory metabolism as revealed by 13C labelling

    PubMed Central

    Lindén, Pernilla; Keech, Olivier; Stenlund, Hans; Gardeström, Per; Moritz, Thomas

    2016-01-01

    Mitochondrial malate dehydrogenase (mMDH) catalyses the interconversion of malate and oxaloacetate (OAA) in the tricarboxylic acid (TCA) cycle. Its activity is important for redox control of the mitochondrial matrix, through which it may participate in regulation of TCA cycle turnover. In Arabidopsis, there are two isoforms of mMDH. Here, we investigated to which extent the lack of the major isoform, mMDH1 accounting for about 60% of the activity, affected leaf metabolism. In air, rosettes of mmdh1 plants were only slightly smaller than wild type plants although the fresh weight was decreased by about 50%. In low CO2 the difference was much bigger, with mutant plants accumulating only 14% of fresh weight as compared to wild type. To investigate the metabolic background to the differences in growth, we developed a 13CO2 labelling method, using a custom-built chamber that enabled simultaneous treatment of sets of plants under controlled conditions. The metabolic profiles were analysed by gas- and liquid- chromatography coupled to mass spectrometry to investigate the metabolic adjustments between wild type and mmdh1. The genotypes responded similarly to high CO2 treatment both with respect to metabolite pools and 13C incorporation during a 2-h treatment. However, under low CO2 several metabolites differed between the two genotypes and, interestingly most of these were closely associated with photorespiration. We found that while the glycine/serine ratio increased, a concomitant altered glutamine/glutamate/α-ketoglutarate relation occurred. Taken together, our results indicate that adequate mMDH activity is essential to shuttle reductants out from the mitochondria to support the photorespiratory flux, and strengthen the idea that photorespiration is tightly intertwined with peripheral metabolic reactions. PMID:26889011

  16. Crystal Structures and Molecular Dynamics Simulations of Thermophilic Malate Dehydrogenase Reveal Critical Loop Motion for Co-Substrate Binding

    PubMed Central

    Luo, Huei-Ru; Wu, Szu-Pei; Hsu, Chun-Hua

    2013-01-01

    Malate dehydrogenase (MDH) catalyzes the conversion of oxaloacetate and malate by using the NAD/NADH coenzyme system. The system is used as a conjugate for enzyme immunoassays of a wide variety of compounds, such as illegal drugs, drugs used in therapeutic applications and hormones. We elucidated the biochemical and structural features of MDH from Thermus thermophilus (TtMDH) for use in various biotechnological applications. The biochemical characterization of recombinant TtMDH revealed greatly increased activity above 60°C and specific activity of about 2,600 U/mg with optimal temperature of 90°C. Analysis of crystal structures of apo and NAD-bound forms of TtMDH revealed a slight movement of the binding loop and few structural elements around the co-substrate binding packet in the presence of NAD. The overall structures did not change much and retained all related positions, which agrees with the CD analyses. Further molecular dynamics (MD) simulation at higher temperatures were used to reconstruct structures from the crystal structure of TtMDH. Interestingly, at the simulated structure of 353 K, a large change occurred around the active site such that with increasing temperature, a mobile loop was closed to co-substrate binding region. From biochemical characterization, structural comparison and MD simulations, the thermal-induced conformational change of the co-substrate binding loop of TtMDH may contribute to the essential movement of the enzyme for admitting NAD and may benefit the enzyme's activity. PMID:24386145

  17. Effects of Supplemental Citrulline-Malate Ingestion on Blood Lactate, Cardiovascular Dynamics, and Resistance Exercise Performance in Trained Males.

    PubMed

    Wax, Benjamin; Kavazis, Andreas N; Luckett, William

    2016-01-01

    Citrulline-malate (CM) has been proposed to provide an ergogenic effect during resistance exercise; however, there is a paucity of research investigating these claims. Therefore, we investigated the impact that CM supplementation would have on repeated bouts of resistance exercise. Fourteen resistance-trained males participated in a randomized, counterbalanced, double-blind study. Subjects were randomly assigned to placebo (PL) or CM (8 g) and performed three sets each of chin-ups, reverse chin-ups, and push-ups to failure. One week later, subjects ingested the other supplement and performed the same protocol. Blood lactate (BLa), heart rate (HR), and blood pressure (BP) were measured preexercise, with BLa measured a second time immediately following the last set, while HR and BP were measured 5 and 10 min postexercise. Citrulline-malate ingestion significantly increased the amount of repetitions performed for each exercise (chin-ups: PL = 28.4 ± 7.1, CM = 32.2 ± 5.6, p = .003; reverse chin-ups: PL = 26.6 ± 5.6, CM = 32.1 ± 7.1, p = .017; push-ups: PL = 89.1 ± 37.4, CM = 97.7 ± 36.1, p < .001). Blood lactate data indicated a time effect (p < .001), but no treatment differences (p = .935). Systolic BP data did not show differences for time (p = .078) or treatment (p = .119). Diastolic BP data did not show differences for time (p = .069), but indicated treatment differences (p = .014) for subjects ingesting CM. Collectively, these findings suggests that CM increased upper-body resistance performance in trained college-age males. PMID:25674699

  18. On the consequences of aluminium stress in rye: repression of two mitochondrial malate dehydrogenase mRNAs.

    PubMed

    Abd El-Moneim, D; Contreras, R; Silva-Navas, J; Gallego, F J; Figueiras, A M; Benito, C

    2015-01-01

    Plants have developed several external and internal aluminium (Al) tolerance mechanisms. The external mechanism best characterised is the exudation of organic acids induced by Al. Rye (Secale cereale L.), one of the most Al-tolerant cereal crops, secretes both citrate and malate from its roots in response to Al. However, the role of malate dehydrogenase (MDH) genes in Al-induced stress has not been studied in rye. We have isolated the ScMDH1 and ScMDH2 genes, encoding two different mitochondrial MDH isozymes, in three Al-tolerant rye cultivars (Ailés, Imperial and Petkus) and one sensitive inbred rye line (Riodeva). These genes, which have seven exons and six introns, were located on the 1R (ScMDH1) and 3RL (ScMDH2) chromosomes. Exon 1 of ScMDH1 and exon 7 of ScMDH2 were the most variable among the different ryes. The hypothetical proteins encoded by these genes were classified as putative mitochondrial MDH isoforms. The phylogenetic relationships obtained using both cDNA and protein sequences indicated that the ScMDH1 and ScMDH2 proteins are orthologous to mitochondrial MDH1 and MDH2 proteins of different Poaceae species. The expression studies of the ScMDH1 and ScMDH2 genes indicate that it is more intense in roots than in leaves. Moreover, the amount of their corresponding mRNAs in roots from plants treated and not treated with Al was higher in the tolerant cultivar Petkus than in the sensitive inbred line Riodeva. In addition, ScMDH1 and ScMDH2 mRNA levels decreased in response to Al stress (repressive behaviour) in the roots of both the tolerant Petkus and the sensitive line Riodeva.

  19. Loss of Mitochondrial Malate Dehydrogenase Activity Alters Seed Metabolism Impairing Seed Maturation and Post-Germination Growth in Arabidopsis.

    PubMed

    Sew, Yun Shin; Ströher, Elke; Fenske, Ricarda; Millar, A Harvey

    2016-06-01

    Mitochondrial malate dehydrogenase (mMDH; EC 1.1.1.37) has multiple roles; the most commonly described is its catalysis of the interconversion of malate and oxaloacetate in the tricarboxylic acid cycle. The roles of mMDH in Arabidopsis (Arabidopsis thaliana) seed development and germination were investigated in mMDH1 and mMDH2 double knockout plants. A significant proportion of mmdh1mmdh2 seeds were nonviable and developed only to torpedo-shaped embryos, indicative of arrested seed embryo growth during embryogenesis. The viable mmdh1mmdh2 seeds had an impaired maturation process that led to slow germination rates as well as retarded post-germination growth, shorter root length, and decreased root biomass. During seed development, mmdh1mmdh2 showed a paler green phenotype than the wild type and exhibited deficiencies in reserve accumulation and reduced final seed biomass. The respiration rate of mmdh1mmdh2 seeds was significantly elevated throughout their maturation, consistent with the previously reported higher respiration rate in mmdh1mmdh2 leaves. Mutant seeds showed a consistently higher content of free amino acids (branched-chain amino acids, alanine, serine, glycine, proline, and threonine), differences in sugar and sugar phosphate levels, and lower content of 2-oxoglutarate. Seed-aging assays showed that quiescent mmdh1mmdh2 seeds lost viability more than 3 times faster than wild-type seeds. Together, these data show the important role of mMDH in the earliest phases of the life cycle of Arabidopsis. PMID:27208265

  20. Effects of Supplemental Citrulline-Malate Ingestion on Blood Lactate, Cardiovascular Dynamics, and Resistance Exercise Performance in Trained Males.

    PubMed

    Wax, Benjamin; Kavazis, Andreas N; Luckett, William

    2016-01-01

    Citrulline-malate (CM) has been proposed to provide an ergogenic effect during resistance exercise; however, there is a paucity of research investigating these claims. Therefore, we investigated the impact that CM supplementation would have on repeated bouts of resistance exercise. Fourteen resistance-trained males participated in a randomized, counterbalanced, double-blind study. Subjects were randomly assigned to placebo (PL) or CM (8 g) and performed three sets each of chin-ups, reverse chin-ups, and push-ups to failure. One week later, subjects ingested the other supplement and performed the same protocol. Blood lactate (BLa), heart rate (HR), and blood pressure (BP) were measured preexercise, with BLa measured a second time immediately following the last set, while HR and BP were measured 5 and 10 min postexercise. Citrulline-malate ingestion significantly increased the amount of repetitions performed for each exercise (chin-ups: PL = 28.4 ± 7.1, CM = 32.2 ± 5.6, p = .003; reverse chin-ups: PL = 26.6 ± 5.6, CM = 32.1 ± 7.1, p = .017; push-ups: PL = 89.1 ± 37.4, CM = 97.7 ± 36.1, p < .001). Blood lactate data indicated a time effect (p < .001), but no treatment differences (p = .935). Systolic BP data did not show differences for time (p = .078) or treatment (p = .119). Diastolic BP data did not show differences for time (p = .069), but indicated treatment differences (p = .014) for subjects ingesting CM. Collectively, these findings suggests that CM increased upper-body resistance performance in trained college-age males.

  1. Effects of essential oils, yeast culture and malate on rumen fermentation, blood metabolites, growth performance and nutrient digestibility of Baluchi lambs fed high-concentrate diets.

    PubMed

    Malekkhahi, M; Tahmasbi, A M; Naserian, A A; Danesh Mesgaran, M; Kleen, J L; Parand, A A

    2015-04-01

    The experiment was conducted to evaluate the effects of dietary supplementation with a mixture of essential oils (MEO), yeast culture (YC) and malate on performance, nutrient digestion, rumen fermentation and blood metabolites of lambs fed high-concentrate growing diets. For this purpose, twenty Baluchi lambs (17.3 ± 0.5 kg body weight and 3 months old) were randomly assigned to four dietary treatments in a completely randomized design with five lambs per treatment. The treatment groups were as follows: (i) control: basal diet without any additive, (ii) basal diet plus 400 mg/day MEO (thymol, carvacrol, eugenol, limonene and cinnamaldehyde), (iii) basal diet with 4 g/day YC and (iv) basal diet plus 4 g/day malate. No differences between the dietary treatments were observed in dry matter intake, average daily gain or feed conversion ratio (p > 0.05). Compared with control and malate treatment, lambs fed MEO and YC had an improved crude protein digestibility (p < 0.05). Yeast culture significantly increased (p > 0.05) cell wall digestibility compared to the other treatments. No differences were observed between treatments with respect to nitrogen balance or ruminal pH and ammonia concentrations (p > 0.05). No differences were observed between treatments with respect to ruminal total volatile fatty acid concentration and molar proportions of acetate, butyrate and valerate. Molar proportion of propionate was higher (p < 0.05) for YC and malate compared to control and MEO. Plasma glucose concentration was higher (p < 0.05) in lambs fed YC and malate than in lambs fed the control or the MEO diet. Blood concentration of triglycerides significantly decreased when feeding the MEO and YC diets (p < 0.05). It was concluded that YC may be more useful as a feed additive for manipulation of rumen fermentation in lambs fed with high-concentrate diets than MEO and malate, because YC enhanced crude protein and cell wall digestibility, ruminal molar proportion

  2. Crystallization and preliminary X-ray diffraction studies of tetrameric malate dehydrogenase from the novel Antarctic psychrophile Flavobacterium frigidimaris KUC-1

    SciTech Connect

    Fujii, Tomomi; Oikawa, Tadao; Muraoka, Ikuo; Soda, Kenji; Hata, Yasuo

    2007-11-01

    A psychrophilic malate dehydrogenase from the novel Antarctic bacterium F. frigidimaris KUC-1 was crystallized using the hanging-drop vapour-diffusion method. The crystals contained one tetrameric molecule per asymmetric unit. The best crystal diffracted to 1.8 Å resolution. Flavobacterium frigidimaris KUC-1 is a novel psychrotolerant bacterium isolated from Antarctic seawater. Malate dehydrogenase (MDH) is an essential metabolic enzyme in the citric acid cycle and has been cloned, overexpressed and purified from F. frigidimaris KUC-1. In contrast to the already known dimeric form of MDH from the psychrophile Aquaspirillium arcticum, F. frigidimaris MDH exists as a tetramer. It was crystallized at 288 K by the hanging-drop vapour-diffusion method using ammonium sulfate as the precipitating agent. The crystal diffracted to a maximum resolution of 1.80 Å. It contains one tetrameric molecule in the asymmetric unit.

  3. Brucine salts of L-alpha-hydroxy acids: brucinium hydrogen (S)-malate pentahydrate and anhydrous brucinium hydrogen (2R,3R)-tartrate at 130 K.

    PubMed

    Smith, Graham; Wermuth, Urs D; White, Jonathan M

    2006-06-01

    The structures of two brucinium (2,3-dimethoxy-10-oxostrychnidinium) salts of the alpha-hydroxy acids L-malic acid and L-tartaric acid, namely brucinium hydrogen (S)-malate pentahydrate, C23H27N2O4+.C4H5O5-.5H2O, (I), and anhydrous brucinium hydrogen (2R,3R)-tartrate, C23H27N2O4+.C4H5O6-,(II), have been determined at 130 K. Compound (I) has two brucinium cations, two hydrogen malate anions and ten water molecules of solvation in the asymmetric unit, and forms an extensively hydrogen-bonded three-dimensional framework structure. In compound (II), the brucinium cations form the common undulating brucine sheet substructures, which accommodate parallel chains of head-to-tail hydrogen-bonded tartrate anion species in the interstitial cavities.

  4. Regulation of glyoxysomal enzymes during germination of cucumber. Temporal changes in translatable mRNAs for isocitrate lyase and malate synthase.

    PubMed

    Weir, E M; Riezman, H; Grienenberger, J M; Becker, W M; Leaver, C J

    1980-12-01

    The relative levels of translatable messenger RNA for isocitrate lyase and malate synthase were determined in the dry seed and for the first seven days of development of cucumber cotyledons. After extraction and quantification of total and poly(A)-rich RNA each day, the RNA fractions were translated in an optimized wheat germ system and the specific polypeptides were immunoprecipitated quantitatively. The radiolabeled isocitrate lyase and malate synthase polypeptides were then fractionated on dodecylsulphate/polyacrylamide gels, visualized by exposure to X-ray film and quantified densitometrically. The relative levels of translatable messenger RNA for these enzymes rise and fall with a developmental program similar to the enzyme activities, but preceding the latter by about one day. This implies that the rise in enzyme activity is dependent upon a prior postgerminative increase in translatable messenger RNA for the enzymes. These studies also suggest that messenger RNA levels may be regulated, at least in part, by light.

  5. Salmonella enterica serovar Typhimurium mutants unable to convert malate to pyruvate and oxaloacetate are avirulent and immunogenic in BALB/c mice.

    PubMed

    Mercado-Lubo, Regino; Leatham, Mary P; Conway, Tyrrell; Cohen, Paul S

    2009-04-01

    Previously, we showed that the Salmonella enterica serovar Typhimurium SR-11 tricarboxylic acid (TCA) cycle must operate as a complete cycle for full virulence after oral infection of BALB/c mice (M. Tchawa Yimga, M. P. Leatham, J. H. Allen, D. C. Laux, T. Conway, and P. S. Cohen, Infect. Immun. 74:1130-1140, 2006). In the same study, we showed that for full virulence, malate must be converted to both oxaloacetate and pyruvate. Moreover, it was recently demonstrated that blocking conversion of succinyl-coenzyme A to succinate attenuates serovar Typhimurium SR-11 but does not make it avirulent; however, blocking conversion of succinate to fumarate renders it completely avirulent and protective against subsequent oral infection with the virulent serovar Typhimurium SR-11 wild-type strain (R. Mercado-Lubo, E. J. Gauger, M. P. Leatham, T. Conway, and P. S. Cohen, Infect. Immun. 76:1128-1134, 2008). Furthermore, the ability to convert succinate to fumarate appeared to be required only after serovar Typhimurium SR-11 became systemic. In the present study, evidence is presented that serovar Typhimurium SR-11 mutants that cannot convert fumarate to malate or that cannot convert malate to both oxaloacetate and pyruvate are also avirulent and protective in BALB/c mice. These results suggest that in BALB/c mice, the malate that is removed from the TCA cycle in serovar Typhimurium SR-11 for conversion to pyruvate must be replenished by succinate or one of its precursors, e.g., arginine or ornithine, which might be available in mouse phagocytes.

  6. Toggle release

    NASA Technical Reports Server (NTRS)

    Graves, Thomas Joseph (Inventor); Yang, Robert Alexander (Inventor); Brown, Christopher William (Inventor)

    1988-01-01

    The invention relates to a pyrotechnic actuated release mechanism which is mechanically two fault tolerant for effecting release. It is particularly well suited for releasably connecting structures to be used in the space environment or in other aerospace applications. The device comprises a fastener plate and fastener body, each attachable to either one of a pair of structures to be joined. The fastener plate and the body are fastenable by a toggle supported at one end on the fastener plate and mounted for universal pivotal movement thereon. At its other end, which is received in a central opening in the fastener body and adapted for limited pivotal movement therein, the toggle is restrained by three retractable latching pins. Each pin is individually retractable by combustion of a pyrotechnic charge. While retraction of all three pins releases the toggle, the fastener is mechanically two fault tolerant since the failure of any single or pair of the latch pins to retract results in an asymmetrical loading on the toggle and its pivotal movement to effect a release. An annular bolt is mounted on the fastener plate as a support for the socket mounting of the toggle whereby its selective axial movement provides a means for pre-loading the toggle.

  7. Use of a microbial model for the determination of drug effects on cell metabolism and energetics: study of citrulline-malate.

    PubMed

    Briand, J; Blehaut, H; Calvayrac, R; Laval-Martin, D

    1992-01-01

    Euglena gracilis can be used as a microbial model to study the effect of drugs on lactate metabolism and gluconeogenetic synthesis. The cell growth and metabolism have been characterized in a 33 mM lactate medium, non-supplemented or supplemented by dl-malate or by l-citrulline alone or by the compound formed by the stoichiometric combination of the two components: the citrulline-malate (Stimol). The malate of the complex accelerated the ammonium disappearance, while the citrulline facilitated the lactate consumption. A synergistic action of the complex, by comparison with the additive effects of the individual components, on most of the parameters studied was detected. A remarkable resistance to anoxia, and a quicker recovery under aeration of the cells supplemented with CM, were evident: after carbonation for 2 min the total nucleotides in the medium were increased by 44 per cent with an unchanged energy charge; and after a prolonged (20 min) anoxia followed by an aeration, the capacities of the cells to synthesize ATP in the presence of excesses of both ADP and phosphate were two-fold higher in Stimol treated cells than in control. PMID:1554874

  8. Chemokine (C-C Motif) Ligand 5 is Involved in Tumor-Associated Dendritic Cell-Mediated Colon Cancer Progression Through Non-Coding RNA MALAT-1.

    PubMed

    Kan, Jung-Yu; Wu, Deng-Chyang; Yu, Fang-Jung; Wu, Cheng-Ying; Ho, Ya-Wen; Chiu, Yen-Jung; Jian, Shu-Fang; Hung, Jen-Yu; Wang, Jaw-Yuan; Kuo, Po-Lin

    2015-08-01

    Tumor micro-environment is a critical factor in the development of cancer. The aim of this study was to investigate the inflammatory cytokines secreted by tumor-associated dendritic cells (TADCs) that contribute to enhanced migration, invasion, and epithelial-to-mesenchymal transition (EMT) in colon cancer. The administration of recombinant human chemokine (C-C motif) ligand 5 (CCL5), which is largely expressed by colon cancer surrounding TADCs, mimicked the stimulation of TADC-conditioned medium on migration, invasion, and EMT in colon cancer cells. Blocking CCL5 by neutralizing antibodies or siRNA transfection diminished the promotion of cancer progression by TADCs. Tumor-infiltrating CD11c(+) DCs in human colon cancer specimens were shown to produce CCL5. The stimulation of colon cancer progression by TADC-derived CCL5 was associated with the up-regulation of non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), which subsequently increased the expression of Snail. Blocking MALAT-1 significantly decreased the TADC-conditioned medium and CCL5-mediated migration and invasion by decreasing the enhancement of Snail, suggesting that the MALAT-1/Snail pathway plays a critical role in TADC-mediated cancer progression. In conclusion, the inhibition of CCL5 or CCL5-related signaling may be an attractive therapeutic target in colon cancer patients.

  9. The mitochondrial malate dehydrogenase 1 gene GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton.

    PubMed

    Wang, Zhi-An; Li, Qing; Ge, Xiao-Yang; Yang, Chun-Lin; Luo, Xiao-Li; Zhang, An-Hong; Xiao, Juan-Li; Tian, Ying-Chuan; Xia, Gui-Xian; Chen, Xiao-Ying; Li, Fu-Guang; Wu, Jia-He

    2015-07-16

    Cotton, an important commercial crop, is cultivated for its natural fibers, and requires an adequate supply of soil nutrients, including phosphorus, for its growth. Soil phosporus exists primarily in insoluble forms. We isolated a mitochondrial malate dehydrogenase (MDH) gene, designated as GhmMDH1, from Gossypium hirsutum L. to assess its effect in enhancing P availability and absorption. An enzyme kinetic assay showed that the recombinant GhmMDH1 possesses the capacity to catalyze the interconversion of oxaloacetate and malate. The malate contents in the roots, leaves and root exudates was significantly higher in GhmMDH1-overexpressing plants and lower in knockdown plants compared with the wild-type control. Knockdown of GhmMDH1 gene resulted in increased respiration rate and reduced biomass whilst overexpression of GhmMDH1 gave rise to decreased respiration rate and higher biomass in the transgenic plants. When cultured in medium containing only insoluble phosphorus, Al-phosphorus, Fe-phosphorus, or Ca-phosphorus, GhmMDH1-overexpressing plants produced significantly longer roots and had a higher biomass and P content than WT plants, however, knockdown plants showed the opposite results for these traits. Collectively, our results show that GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton, owing to its functions in leaf respiration and P acquisition.

  10. The mitochondrial malate dehydrogenase 1 gene GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton

    PubMed Central

    Wang, Zhi-An; Li, Qing; Ge, Xiao-Yang; Yang, Chun-Lin; Luo, Xiao-Li; Zhang, An-Hong; Xiao, Juan-Li; Tian, Ying-Chuan; Xia, Gui-Xian; Chen, Xiao-Ying; Li, Fu-Guang; Wu, Jia-He

    2015-01-01

    Cotton, an important commercial crop, is cultivated for its natural fibers, and requires an adequate supply of soil nutrients, including phosphorus, for its growth. Soil phosporus exists primarily in insoluble forms. We isolated a mitochondrial malate dehydrogenase (MDH) gene, designated as GhmMDH1, from Gossypium hirsutum L. to assess its effect in enhancing P availability and absorption. An enzyme kinetic assay showed that the recombinant GhmMDH1 possesses the capacity to catalyze the interconversion of oxaloacetate and malate. The malate contents in the roots, leaves and root exudates was significantly higher in GhmMDH1-overexpressing plants and lower in knockdown plants compared with the wild-type control. Knockdown of GhmMDH1 gene resulted in increased respiration rate and reduced biomass whilst overexpression of GhmMDH1 gave rise to decreased respiration rate and higher biomass in the transgenic plants. When cultured in medium containing only insoluble phosphorus, Al-phosphorus, Fe-phosphorus, or Ca-phosphorus, GhmMDH1-overexpressing plants produced significantly longer roots and had a higher biomass and P content than WT plants, however, knockdown plants showed the opposite results for these traits. Collectively, our results show that GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton, owing to its functions in leaf respiration and P acquisition. PMID:26179843

  11. Cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 involves a malate:quinone oxidoreductase and an associated cyanide-insensitive electron transfer chain.

    PubMed

    Luque-Almagro, Victor M; Merchán, Faustino; Blasco, Rafael; Igeño, M Isabel; Martínez-Luque, Manuel; Moreno-Vivián, Conrado; Castillo, Francisco; Roldán, M Dolores

    2011-03-01

    The alkaliphilic bacterium Pseudomonas pseudoalcaligenes CECT5344 is able to grow with cyanide as the sole nitrogen source. Membrane fractions from cells grown under cyanotrophic conditions catalysed the production of oxaloacetate from L-malate. Several enzymic activities of the tricarboxylic acid and glyoxylate cycles in association with the cyanide-insensitive respiratory pathway seem to be responsible for the oxaloacetate formation in vivo. Thus, in cyanide-grown cells, citrate synthase and isocitrate lyase activities were significantly higher than those observed with other nitrogen sources. Malate dehydrogenase activity was undetectable, but a malate:quinone oxidoreductase activity coupled to the cyanide-insensitive alternative oxidase was found in membrane fractions from cyanide-grown cells. Therefore, oxaloacetate production was linked to the cyanide-insensitive respiration in P. pseudoalcaligenes CECT5344. Cyanide and oxaloacetate reacted chemically inside the cells to produce a cyanohydrin (2-hydroxynitrile), which was further converted to ammonium. In addition to cyanide, strain CECT5344 was able to grow with several cyano derivatives, such as 2- and 3-hydroxynitriles. The specific system required for uptake and metabolization of cyanohydrins was induced by cyanide and by 2-hydroxynitriles, such as the cyanohydrins of oxaloacetate and 2-oxoglutarate.

  12. Amino acid sequence homology among the 2-hydroxy acid dehydrogenases: mitochondrial and cytoplasmic malate dehydrogenases form a homologous system with lactate dehydrogenase.

    PubMed Central

    Birktoft, J J; Fernley, R T; Bradshaw, R A; Banaszak, L J

    1982-01-01

    The amino acid sequence of porcine heart mitochondrial malate dehydrogenase (mMDH; L-malate: NAD+ oxidoreductase, EC 1.1.1.37) has been compared with the sequences of six different lactate dehydrogenases (LDH; L-lactate: NAD+ oxidoreductase, EC 1.1.1.27) and with the "x-ray" sequence of cytoplasmic malate dehydrogenase (sMDH). The main points are that (i) all three enzymes are homologous; (ii) invariant residues in the catalytic center of these enzymes include a histidine and an internally located aspartate that function as a proton relay system; (iii) numerous residues important to coenzyme binding are conserved, including several glycines and charged residues; and (iv) amino acid side chains present in the subunit interface common to the MDHs and LDHs appear to be better conserved than those in the protein interior. It is concluded that LDH, sMDH, and mMDH are derived from a common ancestral gene and probably have similar catalytic mechanisms. PMID:6959107

  13. Implication of citrate, malate and histidine in the accumulation and transport of nickel in Mesembryanthemum crystallinum and Brassica juncea.

    PubMed

    Amari, Taoufik; Lutts, Stanley; Taamali, Manel; Lucchini, Giorgio; Sacchi, Gian Attilio; Abdelly, Chedly; Ghnaya, Tahar

    2016-04-01

    Citrate, malate and histidine have been involved in many processes including metal tolerance and accumulation in plants. These molecules have been frequently reported to be the potential nickel chelators, which most likely facilitate metal transport through xylem. In this context, we assess here, the relationship between organics acids and histidine content and nickel accumulation in Mesembryanthemum crystallinum and Brassica juncea grown in hydroponic media added with 25, 50 and 100 µM NiCl2. Results showed that M. crystallinum is relatively more tolerant to Ni toxicity than B. juncea. For both species, xylem transport rate of Ni increased with increasing Ni supply. A positive correlation was established between nickel and citrate concentrations in the xylem sap. In the shoot of B. juncea, citric and malic acids concentrations were significantly higher than in the shoot of M. crystallinum. Also, the shoots and roots of B. juncea accumulated much more histidine. In contrast, a higher root citrate concentration was observed in M. crystallinum. These findings suggest a specific involvement of malic and citric acid in Ni translocation and accumulation in M. crystallinum and B. juncea. The high citrate and histidine accumulation especially at 100µM NiCl2, in the roots of M. crystallinum might be among the important factors associated with the tolerance of this halophyte to toxic Ni levels.

  14. Implication of citrate, malate and histidine in the accumulation and transport of nickel in Mesembryanthemum crystallinum and Brassica juncea.

    PubMed

    Amari, Taoufik; Lutts, Stanley; Taamali, Manel; Lucchini, Giorgio; Sacchi, Gian Attilio; Abdelly, Chedly; Ghnaya, Tahar

    2016-04-01

    Citrate, malate and histidine have been involved in many processes including metal tolerance and accumulation in plants. These molecules have been frequently reported to be the potential nickel chelators, which most likely facilitate metal transport through xylem. In this context, we assess here, the relationship between organics acids and histidine content and nickel accumulation in Mesembryanthemum crystallinum and Brassica juncea grown in hydroponic media added with 25, 50 and 100 µM NiCl2. Results showed that M. crystallinum is relatively more tolerant to Ni toxicity than B. juncea. For both species, xylem transport rate of Ni increased with increasing Ni supply. A positive correlation was established between nickel and citrate concentrations in the xylem sap. In the shoot of B. juncea, citric and malic acids concentrations were significantly higher than in the shoot of M. crystallinum. Also, the shoots and roots of B. juncea accumulated much more histidine. In contrast, a higher root citrate concentration was observed in M. crystallinum. These findings suggest a specific involvement of malic and citric acid in Ni translocation and accumulation in M. crystallinum and B. juncea. The high citrate and histidine accumulation especially at 100µM NiCl2, in the roots of M. crystallinum might be among the important factors associated with the tolerance of this halophyte to toxic Ni levels. PMID:26745003

  15. Toggle release

    NASA Technical Reports Server (NTRS)

    Graves, Thomas J. (Inventor); Yang, Robert A. (Inventor); Brown, Christopher W. (Inventor)

    1989-01-01

    A pyrotechnic actuated structural release device 10 which is mechanically two fault tolerant for release. The device 10 comprises a fastener plate 11 and fastener body 12, each attachable to a different one of a pair of structures to be joined. The fastener plate 11 and body 12 are fastenable by a toggle 13 supported at one end on the fastener plate and mounted for universal pivotal movement thereon. At its other end which is received in a central opening in the fastener body 12 and adapted for limited pivotal movement therein the toggle 13 is restrained by three retractable latching pins 61 symmetrically disposed in equiangular spacing about the axis of the toggle 13 and positionable in latching engagement with an end fitting on the toggle. Each pin 61 is individually retractable by combustion of a pyrotechnic charge 77, the expanding gases of which are applied to a pressure receiving face 67 on the latch pin 61 to effect its retraction from the toggle. While retraction of all three pins 62 releases the toggle, the fastener is mechanically two fault tolerant since the failure of any single one or pair of the latch pins to retract results in an asymmetrical loading on the toggle and its pivotal movement to effect a release. An annular bolt 18 is mounted on the fastener plate 11 as a support for the socket mounting 30, 37 of the toggle whereby its selective axial movement provides a means for preloading the toggle.

  16. MiR-375 Is Epigenetically Downregulated by HPV-16 E6 Mediated DNMT1 Upregulation and Modulates EMT of Cervical Cancer Cells by Suppressing lncRNA MALAT1

    PubMed Central

    Liu, Shikai; Song, Lili; Yao, Hairong; Zhang, Liang; Xu, Dongkui; Gao, Fangyuan; Li, Qian

    2016-01-01

    Epigenetic modulation is an important mechanism of miRNA dysregulation in cervical cancer. In this study, we firstly studied how this mechanism contributes to miR-375 downregulation in cervical cancer cells. Then, we further studied the association between miR-375 and MALAT1 (metastasis associated lung adenocarcinoma transcript 1) in epithelial mesenchymal transition (EMT) of the cancer cells. HPV-16 positive SiHa and CaSki cells were used as in vitro model. Our data showed that HPV-16 E6 positively modulated DNMT1 expression in both SiHa and CaSki cells. Knockdown of DNMT1 partly restored miR-375 levels in the cells. The following methylation-specific PCR (MSP) assay and qRT-PCR analysis showed that methylation was common in the promoter region of miR-375 in both SiHa and CaSki cells and demethylation partly restored miR-375 levels in the cells. Therefore, we infer that miR-375 is downregulated partly due to promoter hypermethylation mediated by DNMT1 in HPV-16 positive cervical cancer cells. Our bioinformatics analysis showed that MALAT1 has three putative binding sites with miR-375 and the following dual luciferase assay confirmed two of them. QRT-PCR analysis showed that miR-375 overexpression significantly reduced MALAT1 expression, while MALAT1 overexpression reversely suppressed miR-375 levels. Therefore, we infer that there is a reciprocal regulation between miR-375 and MALAT1 in the cells. In SiHa cells, miR-375 overexpression or MALAT1 siRNA partly restored E-cadherin expression, significantly reduced N-cadherin and also reduced invasion capacity of SiHa cells. Therefore, these results suggest that miR-375 and MALAT1 form a functional axis modulating EMT in cervical cancer. PMID:27658300

  17. The role of nicotinamide–adenine dinucleotide phosphate-dependent malate dehydrogenase and isocitrate dehydrogenase in the supply of reduced nicotinamide–adenine dinucleotide phosphate for steroidogenesis in the superovulated rat ovary

    PubMed Central

    Flint, A. P. F.; Denton, R. M.

    1970-01-01

    1. Superovulated rat ovary was found to contain high activities of NADP–malate dehydrogenase and NADP–isocitrate dehydrogenase. The activity of each enzyme was approximately four times that of glucose 6-phosphate dehydrogenase and equalled or exceeded the activities reported to be present in other mammalian tissues. Fractionation of a whole tissue homogenate of superovulated rat ovary indicated that both enzymes were exclusively cytoplasmic. The tissue was also found to contain pyruvate carboxylase (exclusively mitochondrial), NAD–malate dehydrogenase and aspartate aminotransferase (both mitochondrial and cytoplasmic) and ATP–citrate lyase (exclusively cytoplasmic). 2. The kinetic properties of glucose 6-phosphate dehydrogenase, NADP–malate dehydrogenase and NADP–isocitrate dehydrogenase were determined and compared with the whole-tissue concentrations of their substrates and NADPH; NADPH is a competitive inhibitor of all three enzymes. The concentrations of glucose 6-phosphate, malate and isocitrate in incubated tissue slices were raised at least tenfold by the addition of glucose to the incubation medium, from the values below to values above the respective Km values of the dehydrogenases. Glucose doubled the tissue concentration of NADPH. 3. Steroidogenesis from acetate is stimulated by glucose in slices of superovulated rat ovary incubated in vitro. It was found that this stimulatory effect of glucose can be mimicked by malate, isocitrate, lactate and pyruvate. 4. It is concluded that NADP–malate dehydrogenase or NADP–isocitrate dehydrogenase or both may play an important role in the formation of NADPH in the superovulated rat ovary. It is suggested that the stimulatory effect of glucose on steroidogenesis from acetate results from an increased rate of NADPH formation through one or both dehydrogenases, brought about by the increases in the concentrations of malate, isocitrate or both. Possible pathways involving the two enzymes are discussed

  18. Combined inactivation of the Clostridium cellulolyticum lactate and malate dehydrogenase genes substantially increases ethanol yield from cellulose and switchgrass fermentations

    SciTech Connect

    Li, Yongchao; Tschaplinski, Timothy J; Engle, Nancy L; Hamilton, Choo Yieng; Rodriguez, Jr., Miguel; Liao, James C; Schadt, Christopher Warren; Guss, Adam M; Yang, Yunfeng; Graham, David E

    2012-01-01

    Background: The model bacterium Clostridium cellulolyticum efficiently hydrolyzes crystalline cellulose and hemicellulose, using cellulosomes to degrade lignocellulosic biomass. Although it imports and ferments both pentose and hexose sugars to produce a mixture of ethanol, acetate, lactate, H2 and CO2, the proportion of ethanol is low, which impedes its use in consolidated bioprocessing for biofuels. Therefore genetic engineering will likely be required to improve the ethanol yield. Random mutagenesis, plasmid transformation, and heterologous expression systems have previously been developed for C. cellulolyticum, but targeted mutagenesis has not been reported for this organism. Results: The first targeted gene inactivation system was developed for C. cellulolyticum, based on a mobile group II intron originating from the Lactococcus lactis L1.LtrB intron. This markerless mutagenesis system was used to disrupt both the paralogous L-lactate dehydrogenase (Ccel_2485; ldh) and L-malate dehydrogenase (Ccel_0137; mdh) genes, distinguishing the overlapping substrate specificities of these enzymes. Both mutations were then combined in a single strain. This double mutant produced 8.5-times more ethanol than wild-type cells growing on crystalline cellulose. Ethanol constituted 93% of the major fermentation products (by molarity), corresponding to a molar ratio of ethanol to organic acids of 15, versus 0.18 in wild-type cells. During growth on acid-pretreated switchgrass, the double mutant also produced four-times as much ethanol as wild-type cells. Detailed metabolomic analyses identified increased flux through the oxidative branch of the mutant s TCA pathway. Conclusions: The efficient intron-based gene inactivation system produced the first gene-targeted mutations in C. cellulolyticum. As a key component of the genetic toolbox for this bacterium, markerless targeted mutagenesis enables functional genomic research in C. cellulolyticum and rapid genetic engineering to

  19. Transcriptional regulation of NADP-dependent malate dehydrogenase: comparative genetics and identification of DNA-binding proteins.

    PubMed

    Hameister, Steffen; Becker, Beril; Holtgrefe, Simone; Strodtkötter, Inga; Linke, Vera; Backhausen, Jan E; Scheibe, Renate

    2007-10-01

    The transcriptional regulation of NADP-malate dehydrogenase (NADP-MDH) was analyzed in Arabidopsis ecotypes and other Brassicaceae. The amount of transcript increased twofold after transfer into low temperature (12 degrees C) or high light (750 microE) in all species. Analysis of the genomic DNA reveals that the NADP-MDH gene (At5g58330 in A. thaliana) in Brassicaceae is located between two other genes (At5g58320 and At5g58340 in Arabidopsis), both encoded on the opposite DNA strand. No promoter elements were identified in 5' direction of the NADP-MDH gene, and the expression of NADP-MDH was not affected in knock-out plants carrying a DNA insert in the 5' region. A yeast-one hybrid approach yielded only three DNA-binding proteins for the 500-bp fragment located upstream of the ATG sequence, but 34 proteins for its coding region. However, in Chlamydomonas and in some Poaceae, which do not possess any genes within the 1200 bp upstream region, typical promoter elements were identified. Alignments of genomic DNA reveal that, in contrast to Poaceae, the introns are highly conserved within Brassicaceae. We conclude that in Brassicaceae the majority of regulatory elements are located within the coding region. The NADP-MDH gene of both families evolved from a common precursor, similar to the gene in Chlamydomonas. Changes in the selection pressure allowed the insertion of At5g58340 into the promoter region of a common ancestor. When the demand for transcriptional regulation increased, At5g58340 disappeared in Poaceae, and a promoter developed in the 5' region. In contrast, Brassicaceae maintained At5g58340 and shifted all regulatory elements into the coding region of NADP-MDH.

  20. Improved Production of Propionic Acid in Propionibacterium jensenii via Combinational Overexpression of Glycerol Dehydrogenase and Malate Dehydrogenase from Klebsiella pneumoniae

    PubMed Central

    Liu, Long; Zhuge, Xin; Shin, Hyun-dong; Chen, Rachel R.; Li, Jianghua

    2015-01-01

    Microbial production of propionic acid (PA), an important chemical building block used as a preservative and chemical intermediate, has gained increasing attention for its environmental friendliness over traditional petrochemical processes. In previous studies, we constructed a shuttle vector as a useful tool for engineering Propionibacterium jensenii, a potential candidate for efficient PA synthesis. In this study, we identified the key metabolites for PA synthesis in P. jensenii by examining the influence of metabolic intermediate addition on PA synthesis with glycerol as a carbon source under anaerobic conditions. We also further improved PA production via the overexpression of the identified corresponding enzymes, namely, glycerol dehydrogenase (GDH), malate dehydrogenase (MDH), and fumarate hydratase (FUM). Compared to those in wild-type P. jensenii, the activities of these enzymes in the engineered strains were 2.91- ± 0.17- to 8.12- ± 0.37-fold higher. The transcription levels of the corresponding enzymes in the engineered strains were 2.85- ± 0.19- to 8.07- ± 0.63-fold higher than those in the wild type. The coexpression of GDH and MDH increased the PA titer from 26.95 ± 1.21 g/liter in wild-type P. jensenii to 39.43 ± 1.90 g/liter in the engineered strains. This study identified the key metabolic nodes limiting PA overproduction in P. jensenii and further improved PA titers via the coexpression of GDH and MDH, making the engineered P. jensenii strain a potential industrial producer of PA. PMID:25595755

  1. Adenine nucleotide-dependent and redox-independent control of mitochondrial malate dehydrogenase activity in Arabidopsis thaliana.

    PubMed

    Yoshida, Keisuke; Hisabori, Toru

    2016-06-01

    Mitochondrial metabolism is important for sustaining cellular growth and maintenance; however, the regulatory mechanisms underlying individual processes in plant mitochondria remain largely uncharacterized. Previous redox-proteomics studies have suggested that mitochondrial malate dehydrogenase (mMDH), a key enzyme in the tricarboxylic acid (TCA) cycle and redox shuttling, is under thiol-based redox regulation as a target candidate of thioredoxin (Trx). In addition, the adenine nucleotide status may be another factor controlling mitochondrial metabolism, as respiratory ATP production in mitochondria is believed to be influenced by several environmental stimuli. Using biochemical and reverse-genetic approaches, we addressed the redox- and adenine nucleotide-dependent regulation of mMDH in Arabidopsis thaliana. Recombinant mMDH protein formed intramolecular disulfide bonds under oxidative conditions, but these bonds did not have a considerable effect on mMDH activity. Mitochondria-localized o-type Trx (Trx-o) did not facilitate re-reduction of oxidized mMDH. Determination of the in vivo redox state revealed that mMDH was stably present in the reduced form even in Trx-o-deficient plants. Accordingly, we concluded that mMDH is not in the class of redox-regulated enzymes. By contrast, mMDH activity was lowered by adenine nucleotides (AMP, ADP, and ATP). Each adenine nucleotide suppressed mMDH activity with different potencies and ATP exerted the largest inhibitory effect with a significantly lower K(I). Correspondingly, mMDH activity was inhibited by the increase in ATP/ADP ratio within the physiological range. These results suggest that mMDH activity is finely controlled in response to variations in mitochondrial adenine nucleotide balance. PMID:26946085

  2. Adenine nucleotide-dependent and redox-independent control of mitochondrial malate dehydrogenase activity in Arabidopsis thaliana.

    PubMed

    Yoshida, Keisuke; Hisabori, Toru

    2016-06-01

    Mitochondrial metabolism is important for sustaining cellular growth and maintenance; however, the regulatory mechanisms underlying individual processes in plant mitochondria remain largely uncharacterized. Previous redox-proteomics studies have suggested that mitochondrial malate dehydrogenase (mMDH), a key enzyme in the tricarboxylic acid (TCA) cycle and redox shuttling, is under thiol-based redox regulation as a target candidate of thioredoxin (Trx). In addition, the adenine nucleotide status may be another factor controlling mitochondrial metabolism, as respiratory ATP production in mitochondria is believed to be influenced by several environmental stimuli. Using biochemical and reverse-genetic approaches, we addressed the redox- and adenine nucleotide-dependent regulation of mMDH in Arabidopsis thaliana. Recombinant mMDH protein formed intramolecular disulfide bonds under oxidative conditions, but these bonds did not have a considerable effect on mMDH activity. Mitochondria-localized o-type Trx (Trx-o) did not facilitate re-reduction of oxidized mMDH. Determination of the in vivo redox state revealed that mMDH was stably present in the reduced form even in Trx-o-deficient plants. Accordingly, we concluded that mMDH is not in the class of redox-regulated enzymes. By contrast, mMDH activity was lowered by adenine nucleotides (AMP, ADP, and ATP). Each adenine nucleotide suppressed mMDH activity with different potencies and ATP exerted the largest inhibitory effect with a significantly lower K(I). Correspondingly, mMDH activity was inhibited by the increase in ATP/ADP ratio within the physiological range. These results suggest that mMDH activity is finely controlled in response to variations in mitochondrial adenine nucleotide balance.

  3. WIF1 re-expression in glioblastoma inhibits migration through attenuation of non-canonical WNT signaling by downregulating the lncRNA MALAT1.

    PubMed

    Vassallo, I; Zinn, P; Lai, M; Rajakannu, P; Hamou, M-F; Hegi, M E

    2016-01-01

    Glioblastoma is the most aggressive primary brain tumor in adults and due to the invasive nature cannot be completely removed. The WNT inhibitory factor 1 (WIF1), a secreted inhibitor of WNTs, is systematically downregulated in glioblastoma and acts as strong tumor suppressor. The aim of this study was the dissection of WIF1-associated tumor-suppressing effects mediated by canonical and non-canonical WNT signaling. We found that WIF1 besides inhibiting the canonical WNT pathway selectively downregulates the WNT/calcium pathway associated with significant reduction of p38-MAPK (p38-mitogen-activated protein kinase) phosphorylation. Knockdown of WNT5A, the only WNT ligand overexpressed in glioblastoma, phenocopied this inhibitory effect. WIF1 expression inhibited cell migration in vitro and in an orthotopic brain tumor model, in accordance with the known regulatory function of the WNT/Ca(2+) pathway on migration and invasion. In search of a mediator for this function differential gene expression profiles of WIF1-expressing cells were performed. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long non-coding RNA and key positive regulator of invasion, emerged as the top downregulated gene. Indeed, knockdown of MALAT1 reduced migration in glioblastoma cells, without effect on proliferation. Hence, loss of WIF1 enhances the migratory potential of glioblastoma through WNT5A that activates the WNT/Ca(2+) pathway and MALAT1. These data suggest the involvement of canonical and non-canonical WNT pathways in glioblastoma promoting key features associated with this deadly disease, proliferation on one hand and invasion on the other. Successful targeting will require a dual strategy affecting both canonical and non-canonical WNT pathways.

  4. 17β-Estradiol regulates cell proliferation, colony formation, migration, invasion and promotes apoptosis by upregulating miR-9 and thus degrades MALAT-1 in osteosarcoma cell MG-63 in an estrogen receptor-independent manner

    SciTech Connect

    Fang, Dengfeng; Yang, Hui; Lin, Jing; Teng, Yi; Jiang, Yingying; Chen, Jiao; Li, Yu

    2015-02-20

    In bone, different concentration of estrogen leads to various of physiological processes in osteoblast, such as the proliferation, migration, and apoptosis in an estrogen receptor-dependent manner. But little was known about the estrogen effects on osteosarcoma (OS). In this study, OS cell MG-63 was treated with low (1 nM) or high (100 nM) dose of 17β-Estradiol (E2) with the presence or absence of estrogen receptor α (ERα), for evaluating the E2 effects on proliferation, migration, invasion, colony formation and apoptosis. Consistent with a previous study, high dose of E2 treatment dramatically downregulated expressing level of long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT-1). The observation of upregulation of miR-9 after a high dose of E2 treatment indicated the cause of MALAT-1 reduction. Downregulation of MALAT-1 promoted the combination of SFPQ/PTBP2 complex. It was also observed that the proliferation, migration, invasion, colony formation and apoptosis of OS cells were remarkably affected by high dose of E2 treatment, but not by low dose, in an ERα independent manner. Furthermore, the abolishment of the effects on these physiological processes caused by ectopic expression of miR-9 ASOs suggested the necessity of miR-9 in MALAT-1 regulation. Here we found that the high dose of E2 treatment upregulated miR-9 thus posttranscriptionally regulated MALAT-1 RNA level in OS cells, and then the downregulation of MALAT-1 inhibited cell proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) processes in the E2-dose dependent and ER-independent ways. - Highlights: • E2 affects osteosarcoma cell MG-63 in an Estrogen receptor-independent way. • High dose of E2 treatment upregulates miR-9 which target to MALAT-1 RNA. • Upregulated miR-9 degrades MALAT-1 and thus affects combination of SFPQ/PTBP2. • E2 treatment block cell proliferation, colony formation, mobility, and enhance apoptosis.

  5. Crystallization and crystallographic analysis of the ligand-binding domain of the Pseudomonas putida chemoreceptor McpS in complex with malate and succinate

    PubMed Central

    Gavira, J. A.; Lacal, J.; Ramos, J. L.; García-Ruiz, J. M.; Krell, T.; Pineda-Molina, E.

    2012-01-01

    Methyl-accepting chemotaxis proteins (MCPs) are transmembrane proteins that sense changes in environmental signals, generating a chemotactic response and regulating other cellular processes. MCPs are composed of two main domains: a ligand-binding domain (LBD) and a cytosolic signalling domain (CSD). Here, the crystallization of the LBD of the chemoreceptor McpS (McpS-LBD) is reported. McpS-LBD is responsible for sensing most of the TCA-cycle intermediates in the soil bacterium Pseudomonas putida KT2440. McpS-LBD was expressed, purified and crystallized in complex with two of its natural ligands (malate and succinate). Crystals were obtained by both the counter-diffusion and the hanging-drop vapour-diffusion techniques after pre-incubation of McpS-LBD with the ligands. The crystals were isomorphous and belonged to space group C2, with two molecules per asymmetric unit. Diffraction data were collected at the ESRF synchrotron X-ray source to resolutions of 1.8 and 1.9 Å for the malate and succinate complexes, respectively. PMID:22505412

  6. Phenotypes of gene disruptants in relation to a putative mitochondrial malate-citrate shuttle protein in citric acid-producing Aspergillus niger.

    PubMed

    Kirimura, Kohtaro; Kobayashi, Keiichi; Ueda, Yuka; Hattori, Takasumi

    2016-09-01

    The mitochondrial citrate transport protein (CTP) functions as a malate-citrate shuttle catalyzing the exchange of citrate plus a proton for malate between mitochondria and cytosol across the inner mitochondrial membrane in higher eukaryotic organisms. In this study, for functional analysis, we cloned the gene encoding putative CTP (ctpA) of citric acid-producing Aspergillus niger WU-2223L. The gene ctpA encodes a polypeptide consisting 296 amino acids conserved active residues required for citrate transport function. Only in early-log phase, the ctpA disruptant DCTPA-1 showed growth delay, and the amount of citric acid produced by strain DCTPA-1 was smaller than that by parental strain WU-2223L. These results indicate that the CTPA affects growth and thereby citric acid metabolism of A. niger changes, especially in early-log phase, but not citric acid-producing period. This is the first report showing that disruption of ctpA causes changes of phenotypes in relation to citric acid production in A. niger.

  7. Decreasing the mitochondrial synthesis of malate in potato tubers does not affect plastidial starch synthesis, suggesting that the physiological regulation of ADPglucose pyrophosphorylase is context dependent.

    PubMed

    Szecowka, Marek; Osorio, Sonia; Obata, Toshihiro; Araújo, Wagner L; Rohrmann, Johannes; Nunes-Nesi, Adriano; Fernie, Alisdair R

    2012-12-01

    Modulation of the malate content of tomato (Solanum lycopersicum) fruit by altering the expression of mitochondrially localized enzymes of the tricarboxylic acid cycle resulted in enhanced transitory starch accumulation and subsequent effects on postharvest fruit physiology. In this study, we assessed whether such a manipulation would similarly affect starch biosynthesis in an organ that displays a linear, as opposed to a transient, kinetic of starch accumulation. For this purpose, we used RNA interference to down-regulate the expression of fumarase in potato (Solanum tuberosum) under the control of the tuber-specific B33 promoter. Despite displaying similar reductions in both fumarase activity and malate content as observed in tomato fruit expressing the same construct, the resultant transformants were neither characterized by an increased flux to, or accumulation of, starch, nor by alteration in yield parameters. Since the effect in tomato was mechanistically linked to derepression of the reaction catalyzed by ADP-glucose pyrophosphorylase, we evaluated whether the lack of effect on starch biosynthesis was due to differences in enzymatic properties of the enzyme from potato and tomato or rather due to differential subcellular compartmentation of reductant in the different organs. The results are discussed in the context both of current models of metabolic compartmentation and engineering.

  8. Effects of the dicarboxylic acids malate and fumarate on E. coli O157:H7 and Salmonella Typhimurium populations in pure culture and mixed ruminal culture in in vitro fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dicarboxylic acids malate and fumarate increase ruminal pH, reduce methane production, increase propionate and total VFA production, and reduce lactic acid accumulation in a manner similar to ionophores. The mechanism by which these acids effect the ruminal environment is reported to be through...

  9. Red Clover Coumarate 3'-Hydroxylase (CYP98A44) is Capable of Hydroxylating P-Coumaroyl-Shikimate but not P-Coumaroyl-Malate: Implications for the Biosynthesis of Phaselic Acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red clover (Trifolium pratense) leaves accumulate several µmol of phaselic acid [2-O-caffeoyl-L-malate] per gram fresh weight. Post-harvest oxidation of such o-diphenols to o-quinones by endogenous polyphenol oxidases prevents breakdown of forage protein during storage. Forages like alfalfa (Medicag...

  10. Mitochondria from the left heart ventricles of both normotensive and spontaneously hypertensive rats oxidize externally added NADH mostly via a novel malate/oxaloacetate shuttle as reconstructed in vitro.

    PubMed

    Atlante, Anna; Seccia, Teresa M; De Bari, Lidia; Marra, Ersilia; Passarella, Salvatore

    2006-07-01

    A substantial increase in NADH production, arising from accelerated glycolysis, occurs in cardiac hypertrophy and this raises the question of how the NADH is oxidised. We have addressed this problem by reconstructing appropriate mitochondrial shuttles in vitro, using mitochondria from the left ventricles of both normotensive and spontaneously hypertensive rats at 5 and 24 weeks of age as model systems for left ventricle hypertrophy and hypertrophy/hypertension respectively. We found that most NADH oxidation occurs via a novel malate/oxaloacetate shuttle, the activity of which increases with time and with the progression of hypertrophy and development of hypertension as judged by statistical ANOVA analysis. In contrast, alpha-glycerol-phosphate and the malate/aspartate shuttles were shown to make only a minor contribution to NADH oxidation in a manner essentially independent of age and progression of hypertrophy/hypertension. The rate of malate transport in exchange with oxaloacetate proved to limit the rate of NADH oxidation via this malate/oxaloacetate shuttle.

  11. Characterization of Yersinia enterocolitica, Y. intermedia, Y. aldovae, Y. frederiksenii, Y. kristensenii and Y. pseudotuberculosis by electrophoretic polymorphism of acid phosphatase, esterases, and glutamate and malate dehydrogenases.

    PubMed

    Goullet, P; Picard, B

    1988-02-01

    Acid phosphatase, esterases, and glutamate and malate dehydrogenases of 192 strains of Yersinia enterocolitica, Y. intermedia, Y. aldovae, Y. frederiksenii, Y. kristensenii and Y. pseudotuberculosis were analysed by horizontal polyacrylamide agarose gel electrophoresis and by isoelectrofocusing in thin-layer polyacrylamide gels. The six species were clearly separated from each other by their distinct enzyme electrophoretic polymorphism. For Y. enterocolitica, the strains of biotype 5 were differentiated from the other biotypes by the mobility of glutamate dehydrogenase. For Y. frederiksenii, six zymotypes were delineated by pI and by the mobility of the enzymes. Variation in number or mobility of esterases within each species could represent a marker for epidemiological and ecological analyses. A linear relationship was obtained between the mean genetic diversity coefficient of enzymes and the mean percentage DNA-DNA relatedness of Y. intermedia, Y. aldovae, Y. enterocolitica and Y. frederiksenii.

  12. Multiple polypeptides immunologically related to beta-poly(L-malate) hydrolase (polymalatase) in the plasmodium of the slime mold Physarum polycephalum.

    PubMed

    Karl, M; Holler, E

    1998-01-15

    Plasmodia of Physarum polycephalum contain large amounts of the cell-type-specific polyanion beta-poly(L-malate) and of a corresponding specific hydrolase (polymalatase), both expressed in the plasmodial form of the organism. We have partially purified polymalatase, the preparation consisting of several polypeptides, which could not be separated without destroying the hydrolase activity. Polypeptides of 68 kDa and 97 kDa were identified as polymalatases. Both were glycosylated, the 68-kDa form giving rise to a 54-kDa form when deglycosylated, and the 97-kDa form giving rise to an 88-kDa polypeptide that was indistinguishable from an 88-kDa inactive species also contained in the enzyme preparation. Antisera against each of these proteins were used to detect the intracellular distribution of the proteins. We found that the antisera crossreacted with the three proteins and, furthermore, with a multiplicity of polypeptides ubiquitously distributed over the plasmodium. Results of a two-dimensional non-denaturing in the first dimension and SDS-denaturing polyacrylamide gel electrophoresis in the second dimension suggested that the proteins were derived from a 200-kDa 'precursor' protein by proteolytic fragmentation. Polymalatase activity could be generated from a high molecular-mass precursor. According to several pieces of evidence, the proteolytic nicking occurred within plasmodia. The fragments were sticky and gave rise to preferred sizes of nicked macromolecules. The observed multiplicity varied as a function of the age of the cultures. The cellular distribution and the intracellular pH value were not compatible with an in situ polymalatase activity and suggested other, presently unknown, function(s) such as in the transportation of beta-poly(L-malate) from the nucleus to the culture medium.

  13. SENSITIVE TO PROTON RHIZOTOXICITY1, CALMODULIN BINDING TRANSCRIPTION ACTIVATOR2, and other transcription factors are involved in ALUMINUM-ACTIVATED MALATE TRANSPORTER1 expression.

    PubMed

    Tokizawa, Mutsutomo; Kobayashi, Yuriko; Saito, Tatsunori; Kobayashi, Masatomo; Iuchi, Satoshi; Nomoto, Mika; Tada, Yasuomi; Yamamoto, Yoshiharu Y; Koyama, Hiroyuki

    2015-03-01

    In Arabidopsis (Arabidopsis thaliana) the root apex is protected from aluminum (Al) rhizotoxicity by excretion of malate, an Al chelator, by ALUMINUM-ACTIVATED MALATE TRANSPORTER1 (AtALMT1). AtALMT1 expression is fundamentally regulated by the SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) zinc finger protein, but other transcription factors have roles that enable Al-inducible expression with a broad dynamic range. In this study, we characterized multiple cis-elements in the AtALMT1 promoter that interact with transcription factors. In planta complementation assays of AtALMT1 driven by 5' truncated promoters of different lengths showed that the promoter region between -540 and 0 (the first ATG) restored the Al-sensitive phenotype of atalm1 and thus contains cis-elements essential for AtALMT1 expression for Al tolerance. Computation of overrepresented octamers showed that eight regions in this promoter region contained potential cis-elements involved in Al induction and STOP1 regulation. Mutation in a position around -297 from the first ATG completely inactivated AtALMT1 expression and Al response. In vitro binding assays showed that this region contained the STOP1 binding site, which accounted for the recognition by four zinc finger domains of the protein. Other positions were characterized as cis-elements that regulated expression by repressors and activators and a transcription factor that determines root tip expression of AtALMT1. From the consensus of known cis-elements, we identified CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR2 to be an activator of AtALMT1 expression. Al-inducible expression of AtALMT1 changed transcription starting sites, which increased the abundance of transcripts with a shortened 5' untranslated region. The present analyses identified multiple mechanisms that regulate AtALMT1 expression.

  14. Alkaloids as Inhibitors of Malate Synthase from Paracoccidioides spp.: Receptor-Ligand Interaction-Based Virtual Screening and Molecular Docking Studies, Antifungal Activity, and the Adhesion Process

    PubMed Central

    Costa, Fausto Guimaraes; Neto, Benedito Rodrigues da Silva; Gonçalves, Ricardo Lemes; da Silva, Roosevelt Alves; de Oliveira, Cecília Maria Alves; Kato, Lucília; Freitas, Carla dos Santos; Giannini, Maria José Soares Mendes; da Silva, Julhiany de Fátima; Soares, Célia Maria de Almeida

    2015-01-01

    Paracoccidioides is the agent of paracoccidioidomycosis. Malate synthase plays a crucial role in the pathogenicity and virulence of various fungi, such as those that are human pathogens. Thus, an inhibitor of this enzyme may be used as a powerful antifungal without side effects in patients once these enzymes are absent in humans. Here, we searched for compounds with inhibitory capacity against the malate synthase of Paracoccidioides species (PbMLS). The three-dimensional (3D) structure of PbMLS was determined using the I-TASSER server. Compounds were selected from the ZINC database. Based on the mechanism underlying the interaction of the compounds with PbMLS, it was possible to identify β-carboline moiety as a standard key structure. The compounds with β-carboline moiety that are available in our laboratories were investigated. A total of nine alkaloid compounds were selected. The primary mechanisms of interaction of the alkaloid compounds in the binding pocket of PbMLS were identified and compared with the mechanism of interaction of acetyl coenzyme A (acetyl-CoA). We discovered that the amphipathic nature of the compounds, concomitant with the presence of β-carboline moiety, was crucial for their stability in the binding pocket of PbMLS. In addition, the importance of a critical balance of the polar and nonpolar contacts of the compounds in this region was observed. Four β-carboline alkaloid compounds showed the ability to inhibit recombinant PbMLS (PbMLSr) activity, Paracoccidioides species growth, and adhesion of the fungus and PbMLSr to the extracellular matrix components. The cytotoxicity of the alkaloids was also evaluated. PMID:26124176

  15. Alkaloids as inhibitors of malate synthase from Paracoccidioides spp.: receptor-ligand interaction-based virtual screening and molecular docking studies, antifungal activity, and the adhesion process.

    PubMed

    Costa, Fausto Guimaraes; Neto, Benedito Rodrigues da Silva; Gonçalves, Ricardo Lemes; da Silva, Roosevelt Alves; de Oliveira, Cecília Maria Alves; Kato, Lucília; Freitas, Carla Dos Santos; Giannini, Maria José Soares Mendes; da Silva, Julhiany de Fátima; Soares, Célia Maria de Almeida; Pereira, Maristela

    2015-09-01

    Paracoccidioides is the agent of paracoccidioidomycosis. Malate synthase plays a crucial role in the pathogenicity and virulence of various fungi, such as those that are human pathogens. Thus, an inhibitor of this enzyme may be used as a powerful antifungal without side effects in patients once these enzymes are absent in humans. Here, we searched for compounds with inhibitory capacity against the malate synthase of Paracoccidioides species (PbMLS). The three-dimensional (3D) structure of PbMLS was determined using the I-TASSER server. Compounds were selected from the ZINC database. Based on the mechanism underlying the interaction of the compounds with PbMLS, it was possible to identify β-carboline moiety as a standard key structure. The compounds with β-carboline moiety that are available in our laboratories were investigated. A total of nine alkaloid compounds were selected. The primary mechanisms of interaction of the alkaloid compounds in the binding pocket of PbMLS were identified and compared with the mechanism of interaction of acetyl coenzyme A (acetyl-CoA). We discovered that the amphipathic nature of the compounds, concomitant with the presence of β-carboline moiety, was crucial for their stability in the binding pocket of PbMLS. In addition, the importance of a critical balance of the polar and nonpolar contacts of the compounds in this region was observed. Four β-carboline alkaloid compounds showed the ability to inhibit recombinant PbMLS (PbMLSr) activity, Paracoccidioides species growth, and adhesion of the fungus and PbMLSr to the extracellular matrix components. The cytotoxicity of the alkaloids was also evaluated.

  16. Loss of Mitochondrial Malate Dehydrogenase Activity Alters Seed Metabolism Impairing Seed Maturation and Post-Germination Growth in Arabidopsis1[OPEN

    PubMed Central

    2016-01-01

    Mitochondrial malate dehydrogenase (mMDH; EC 1.1.1.37) has multiple roles; the most commonly described is its catalysis of the interconversion of malate and oxaloacetate in the tricarboxylic acid cycle. The roles of mMDH in Arabidopsis (Arabidopsis thaliana) seed development and germination were investigated in mMDH1 and mMDH2 double knockout plants. A significant proportion of mmdh1mmdh2 seeds were nonviable and developed only to torpedo-shaped embryos, indicative of arrested seed embryo growth during embryogenesis. The viable mmdh1mmdh2 seeds had an impaired maturation process that led to slow germination rates as well as retarded post-germination growth, shorter root length, and decreased root biomass. During seed development, mmdh1mmdh2 showed a paler green phenotype than the wild type and exhibited deficiencies in reserve accumulation and reduced final seed biomass. The respiration rate of mmdh1mmdh2 seeds was significantly elevated throughout their maturation, consistent with the previously reported higher respiration rate in mmdh1mmdh2 leaves. Mutant seeds showed a consistently higher content of free amino acids (branched-chain amino acids, alanine, serine, glycine, proline, and threonine), differences in sugar and sugar phosphate levels, and lower content of 2-oxoglutarate. Seed-aging assays showed that quiescent mmdh1mmdh2 seeds lost viability more than 3 times faster than wild-type seeds. Together, these data show the important role of mMDH in the earliest phases of the life cycle of Arabidopsis. PMID:27208265

  17. Reusable Release Mechanism

    NASA Technical Reports Server (NTRS)

    Bunker, J. W.; Ritchie, R. S.

    1984-01-01

    Slider release mechanism reusable. Bears heavy loads while latched, yet gives smooth release motion. Release effected by explosively driving perpendicular slider out of engagement with load-bearing shank. Device has potential industrial applications such as emergency release of lifting cables from helicopters, cranes and hoists.

  18. Common catabolic enzyme patterns in a microplankton community of the Humboldt Current System off northern and central-south Chile: Malate dehydrogenase activity as an index of water-column metabolism in an oxygen minimum zone

    NASA Astrophysics Data System (ADS)

    González, R. R.; Quiñones, R. A.

    2009-07-01

    An extensive subsurface oxygen minimum zone off northern and central-south Chile, associated with the Peru-Chile undercurrent, has important effects on the metabolism of the organisms inhabiting therein. Planktonic species deal with the hypoxic and anoxic environments by relying on biochemical as well as physiological processes related to their anaerobic metabolisms. Here we characterize, for the first time, the potential enzymatic activities involved in the aerobic and anaerobic energy production pathways of microplanktonic organisms (<100 μm), their relationship, and this relationship's association with the oxygen concentration and microplanktonic biomass in the oxygen minimum zone and adjacent areas of the Humboldt Current System water column. Our results demonstrate significant potential enzymatic activity of catabolic pathways in the oxygen minimum zone. Malate dehydrogenase had the highest oxidizing activity of nicotinamide adenine dinucleotide (reduced form) in the batch of catabolic enzymatic activities assayed, including potential pyruvate oxidoreductases activity, the electron transport system, and dissimilatory nitrate reductase. Malate dehydrogenase correlated significantly with almost all the enzymes analyzed within and above the oxygen minimum zone, and also with the oxygen concentration and microplankton biomass in the water column of the Humboldt Current System, especially in the oxygen minimum zone off Iquique. These results suggest a possible specific pattern for the catabolic activity of the microplanktonic realm associated with the oxygen minimum zone spread along the Humboldt Current System off Chile. We hypothesize that malate dehydrogenase activity could be an appropriate indicator of microplankton catabolism in the oxygen minimum zone and adjacent areas.

  19. Plants Possess a Cyclic Mitochondrial Metabolic Pathway similar to the Mammalian Metabolic Repair Mechanism Involving Malate Dehydrogenase and l-2-Hydroxyglutarate Dehydrogenase.

    PubMed

    Hüdig, Meike; Maier, Alexander; Scherrers, Isabell; Seidel, Laura; Jansen, Erwin E W; Mettler-Altmann, Tabea; Engqvist, Martin K M; Maurino, Veronica G

    2015-09-01

    Enzymatic side reactions can give rise to the formation of wasteful and toxic products that are removed by metabolite repair pathways. In this work, we identify and characterize a mitochondrial metabolic repair mechanism in Arabidopsis thaliana involving malate dehydrogenase (mMDH) and l-2-hydroxyglutarate dehydrogenase (l-2HGDH). We analyze the kinetic properties of both A. thaliana mMDH isoforms, and show that they produce l-2-hydroxyglutarate (l-2HG) from 2-ketoglutarate (2-KG) at low rates in side reactions. We identify A. thaliana l-2HGDH as a mitochondrial FAD-containing oxidase that converts l-2HG back to 2-KG. Using loss-of-function mutants, we show that the electrons produced in the l-2HGDH reaction are transferred to the mitochondrial electron transport chain through the electron transfer protein (ETF). Thus, plants possess the biochemical components of an l-2HG metabolic repair system identical to that found in mammals. While deficiencies in the metabolism of l-2HG result in fatal disorders in mammals, accumulation of l-2HG in plants does not adversely affect their development under a range of tested conditions. However, orthologs of l-2HGDH are found in all examined genomes of viridiplantae, indicating that the repair reaction we identified makes an essential contribution to plant fitness in as yet unidentified conditions in the wild. PMID:26203119

  20. The enhancement of tolerance to salt and cold stresses by modifying the redox state and salicylic acid content via the cytosolic malate dehydrogenase gene in transgenic apple plants.

    PubMed

    Wang, Qing-Jie; Sun, Hong; Dong, Qing-Long; Sun, Tian-Yu; Jin, Zhong-Xin; Hao, Yu-Jin; Yao, Yu-Xin

    2016-10-01

    In this study, we characterized the role of an apple cytosolic malate dehydrogenase gene (MdcyMDH) in the tolerance to salt and cold stresses and investigated its regulation mechanism in stress tolerance. The MdcyMDH transcript was induced by mild cold and salt treatments, and MdcyMDH-overexpressing apple plants possessed improved cold and salt tolerance compared to wild-type (WT) plants. A digital gene expression tag profiling analysis revealed that MdcyMDH overexpression largely altered some biological processes, including hormone signal transduction, photosynthesis, citrate cycle and oxidation-reduction. Further experiments verified that MdcyMDH overexpression modified the mitochondrial and chloroplast metabolisms and elevated the level of reducing power, primarily caused by increased ascorbate and glutathione, as well as the increased ratios of ascorbate/dehydroascorbate and glutathione/glutathione disulphide, under normal and especially stress conditions. Concurrently, the transgenic plants produced a high H2 O2 content, but a low O2·- production rate was observed compared to the WT plants. On the other hand, the transgenic plants accumulated more free and total salicylic acid (SA) than the WT plants under normal and stress conditions. Taken together, MdcyMDH conferred the transgenic apple plants a higher stress tolerance by producing more reductive redox states and increasing the SA level; MdcyMDH could serve as a target gene to genetically engineer salt- and cold-tolerant trees. PMID:26923485

  1. EZH2 promotes cell migration and invasion but not alters cell proliferation by suppressing E-cadherin, partly through association with MALAT-1 in pancreatic cancer

    PubMed Central

    Han, Ting; Jiao, Feng; Hu, Hai; Yuan, Cuncun; Wang, Lei; Jin, Zi-Liang; Song, Wei-feng; Wang, Li-Wei

    2016-01-01

    Enhancer of zeste homolog 2 (EZH2) is an essential component of the polycomb repressive complex 2 (PRC2), which is required for epigenetic silencing of target genes, including those affecting cancer progression. Its role in pancreatic cancer remains to be clarified; therefore, we investigated the effects of aberrantly expressed EZH2 on pancreatic cancer. We found that EZH2 expression is up-regulated in pancreatic cancer tissues and positively correlated with lymph node metastasis and advanced clinical stage in pancreatic cancer patients. EZH2 knockdown in pancreatic cancer cell lines inhibited cell migration and invasion, but did not alter cell proliferation. Silencing of EZH2 also increased E-cadherin expression in vitro, and E-cadherin expression was inversely correlated with EZH2 expression in pancreatic cancer tissue samples. Patients with high EZH2 and low E-cadherin expression had the worst prognosis. RIP and ChIP assays suggest that EZH2 is recruited to the E-cadherin promoter by the long non-coding RNA, MALAT-1 (metastasis associated in lung adenocarcinoma transcript 1), where it represses E-cadherin expression. Our results show that EZH2-based therapies may be an option for the treatment of pancreatic cancer. PMID:26848980

  2. EZH2 promotes cell migration and invasion but not alters cell proliferation by suppressing E-cadherin, partly through association with MALAT-1 in pancreatic cancer.

    PubMed

    Han, Ting; Jiao, Feng; Hu, Hai; Yuan, Cuncun; Wang, Lei; Jin, Zi-Liang; Song, Wei-Feng; Wang, Li-Wei

    2016-03-01

    Enhancer of zeste homolog 2 (EZH2) is an essential component of the polycomb repressive complex 2 (PRC2), which is required for epigenetic silencing of target genes, including those affecting cancer progression. Its role in pancreatic cancer remains to be clarified; therefore, we investigated the effects of aberrantly expressed EZH2 on pancreatic cancer. We found that EZH2 expression is up-regulated in pancreatic cancer tissues and positively correlated with lymph node metastasis and advanced clinical stage in pancreatic cancer patients. EZH2 knockdown in pancreatic cancer cell lines inhibited cell migration and invasion, but did not alter cell proliferation. Silencing of EZH2 also increased E-cadherin expression in vitro, and E-cadherin expression was inversely correlated with EZH2 expression in pancreatic cancer tissue samples. Patients with high EZH2 and low E-cadherin expression had the worst prognosis. RIP and ChIP assays suggest that EZH2 is recruited to the E-cadherin promoter by the long non-coding RNA, MALAT-1 (metastasis associated in lung adenocarcinoma transcript 1), where it represses E-cadherin expression. Our results show that EZH2-based therapies may be an option for the treatment of pancreatic cancer.

  3. Hypersensitivity of Arabidopsis TAXIMIN1 overexpression lines to light stress is correlated with decreased sinapoyl malate abundance and countered by the antibiotic cefotaxime

    PubMed Central

    Colling, Janine; Pollier, Jacob; Bossche, Robin Vanden; Makunga, Nokwanda Pearl; Pauwels, Laurens; Goossens, Alain

    2016-01-01

    ABSTRACT Peptide signaling in plants is involved in regulating development,1,2 ensuring cross pollination through initiation of self-incompatibility4 and assisting with recognition of beneficial (nitrogen fixing bacteria5) or unfavorable organisms (pathogens6 or herbivores7). Peptides function to help plants to respond to a changing environment and improve their chances of survival. Constitutive expression of the gene encoding a novel cysteine rich peptide TAXIMIN1 (TAX1) resulted in fusion of lateral organs and in abnormal fruit morphology. TAX1 signaling functions independently from transcription factors known to play a role in this process such as LATERAL ORGAN FUSION1 (LOF1). Here, we report that the TAX1 promoter is not induced by the LOF1 transcription factor and that the TAX1 peptide neither interferes with transcriptional activation by LOF1.1 or transcriptional repression by LOF1.2. Furthermore, we found that TAX1 overexpressing lines were hypersensitive to continuous light, which may be reflected by a decreased accumulation of the UV-B protecting compound sinapoyl-malate. Finally, adding the antibiotic cefotaxime to the medium surprisingly countered the light hypersensitivity phenotype of TAX1 overexpressing seedlings. PMID:26967827

  4. NADP-Malate Dehydrogenase in the C4 Plant Flaveria bidentis (Cosense Suppression of Activity in Mesophyll and Bundle-Sheath Cells and Consequences for Photosynthesis).

    PubMed Central

    Trevanion, S. J.; Furbank, R. T.; Ashton, A. R.

    1997-01-01

    Flaveria bidentis, a C4 dicot, was transformed with sorghum (a monocot) cDNA clones encoding NADP-malate dehydrogenase (NADP-MDH; EC 1.1.1.82) driven by the cauliflower mosaic virus 35S promoter. Although these constructs were designed for over-expression, many transformants contained between 5 and 50% of normal NADP-MDH activity, presumably by cosense suppression of the native gene. The activities of a range of other photosynthetic enzymes were unaffected. Rates of photosynthesis in plants with less than about 10% of normal activity were reduced at high light and at high [CO2], but were unaffected at low light or at [CO2] below about 150 [mu]L L-1. The large decrease in maximum activity of NADP-MDH was accompanied by an increase in the activation state of the enzyme. However, the activation state was unaffected in plants with 50% of normal activity. Metabolic flux control analysis of plants with a range of activities demonstrates that this enzyme is not important in regulating the steady-state flux through C4 photosynthesis in F. bidentis. Cosense suppression of gene expression was similarly effective in both the mesophyll and bundle-sheath cells. Photosynthesis of plants with very low activity of NADP-MDH in the bundle-sheath cells was only slightly inhibited, suggesting that the presence of the enzyme in this compartment is not essential for supporting maximum rates of photosynthesis. PMID:12223666

  5. CO(2) and O(2) Exchanges in the CAM Plant Ananas comosus (L.) Merr: Determination of Total and Malate-Decorboxylation-Dependent CO(2)-Assimilation Rates; Study of Light O(2)-Uptake.

    PubMed

    Cote, F X; Andre, M; Folliot, M; Massimino, D; Daguenet, A

    1989-01-01

    Photosynthesis and light O(2)-uptake of the aerial portion of the CAM plant Ananas comosus (L.) merr. were studied by CO(2) and O(2) gas exchange measurements. The amount of CO(2) which was fixed during a complete day-night cycle was equal to the amount of total net O(2) evolved. This finding justifies the assumption that in each time interval of the light period, the difference between the rates of net O(2)-evolution and of net light atmospheric CO(2)-uptake give the rates of malate-decarboxylation-dependent CO(2) assimilation. Based upon this hypothesis, the following photosynthetic characteristics were observed: (a) From the onset of the light to midphase IV of CAM, the photosynthetic quotient (net O(2) evolved/net CO(2) fixed) was higher than 1. This indicates that malate-decarboxylation supplied CO(2) for the photosynthetic carbon reduction cycle during this period. (b) In phase III and early phase IV, the rate of CO(2) assimilation deduced from net O(2)-evolution was 3 times higher than the maximum rate of atmospheric CO(2)-fixation during phase IV. A conceivable explanation for this stimulation of photosynthesis is that the intracellular CO(2)-concentration was high because of malate decarboxylation. (c) During the final hours of the light period, the photosynthetic quotient decreased below 1. This may be the result of CO(2)-fixation by phosphoenolpyruvate-carboxylase activity and malate accumulation. Based upon this hypothesis, the gas exchange data indicates that at least 50% of the CO(2) fixed during the last hour of the light period was stored as malate. Light O(2)-uptake determined with (18)O(2) showed two remarkable characteristics: from the onset of the light until midphase IV the rate of O(2)-uptake increased progressively; during the following part of the light period, the rate of O(2)-uptake was 3.5 times higher than the maximum rate of CO(2)-uptake. When malate decarboxylation was reduced or suppressed after a night in a CO(2)-free atmosphere or

  6. ELECTROMAGNETIC RELEASE MECHANISM

    DOEpatents

    Michelson, C.

    1960-09-13

    An electromagnetic release mechanism is offered that may be used, for example, for supporting a safety rod for a nuclear reactor. The release mechanism is designed to have a large excess holding force and a rapid, uniform, and dependable release. The fast release is accomplished by providing the electromagnet with slotttd polts separated by an insulating potting resin, and by constructing the poles with a ferro-nickel alloy. The combination of these two features materially reduces the eddy current power density whenever the magnetic field changes during a release operation. In addition to these features, the design of the armature is such as to provide ready entrance of fluid into any void that might tend to form during release of the armature. This also improves the release time for the mechanism. The large holding force for the mechanism is accomplished by providing a small, selected, uniform air gap between the inner pole piece and the armature.

  7. Multicomponent Implant Releasing Dexamethasone

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Ashammakhi, N.

    2008-02-01

    Several inflammatory conditions are usually treated with corticosteroids. There are various problems like side effects with traditional applications of steroids, e.g. topical, or systemic routes. Local drug delivery systems have been studied and developed to gain more efficient administration with fewer side effects. Earlier, we reported on developing Dexamethasone (DX) releasing biodegradable fibers. However, their drug release properties were not satisfactory in terms of onset of drug release. Thus, we assessed the development of multicomponent (MC) implant to enhance earlier drug release from such biodegradable fibers. Poly (lactide-co-glycolide) (PLGA) and 2 wt-% and 8 wt-% DX were compounded and extruded with twin-screw extruder to form of fibers. Some of the fibers were sterilized to obtain a change in drug release properties. Four different fiber classes were studied: 2 wt-%, 8 wt-%, sterilized 2 wt-%, and sterilized 8 wt-%. 3×4 different DX-releasing fibers were then heat-pressed to form one multicomponent rod. Half of the rods where sterilized. Drug release was measured from initial fibers and multicomponent rods using a UV/VIS spectrometer. Shear strength and changes in viscosity were also measured. Drug release studies showed that drug release commenced earlier from multicomponent rods than from component fibers. Drug release from multicomponent rods lasted from day 30 to day 70. The release period of sterilized rods extended from day 23 to day 57. When compared to the original component fibers, the drug release from MC rods commenced earlier. The initial shear strength of MC rods was 135 MPa and decreased to 105 MPa during four weeks of immersion in phosphate buffer solution. Accordingly, heat pressing has a positive effect on drug release. After four weeks in hydrolysis, no disintegration was observed.

  8. Ca2+ Activation kinetics of the two aspartate-glutamate mitochondrial carriers, aralar and citrin: role in the heart malate-aspartate NADH shuttle.

    PubMed

    Contreras, Laura; Gomez-Puertas, Paulino; Iijima, Mikio; Kobayashi, Keiko; Saheki, Takeyori; Satrústegui, Jorgina

    2007-03-01

    Ca(2+) regulation of the Ca(2+) binding mitochondrial carriers for aspartate/glutamate (AGCs) is provided by their N-terminal extensions, which face the intermembrane space. The two mammalian AGCs, aralar and citrin, are members of the malate-aspartate NADH shuttle. We report that their N-terminal extensions contain up to four pairs of EF-hand motifs plus a single vestigial EF-hand, and have no known homolog. Aralar and citrin contain one fully canonical EF-hand pair and aralar two additional half-pairs, in which a single EF-hand is predicted to bind Ca(2+). Shuttle activity in brain or skeletal muscle mitochondria, which contain aralar as the major AGC, is activated by Ca(2+) with S(0.5) values of 280-350 nm; higher than those obtained in liver mitochondria (100-150 nm) that contain citrin as the major AGC. We have used aralar- and citrin-deficient mice to study the role of the two isoforms in heart, which expresses both AGCs. The S(0.5) for Ca(2+) activation of the shuttle in heart mitochondria is about 300 nm, and it remains essentially unchanged in citrin-deficient mice, although it undergoes a drastic reduction to about 100 nm in aralar-deficient mice. Therefore, aralar and citrin, when expressed as single isoforms in heart, confer differences in Ca(2+) activation of shuttle activity, probably associated with their structural differences. In addition, the results reveal that the two AGCs fully account for shuttle activity in mouse heart mitochondria and that no other glutamate transporter can replace the AGCs in this pathway.

  9. Oxaloacetate-to-malate conversion by mineral photoelectrochemistry: implications for the viability of the reductive tricarboxylic acid cycle in prebiotic chemistry

    NASA Astrophysics Data System (ADS)

    Guzman, Marcelo I.; Martin, Scot T.

    2008-10-01

    The carboxylic acids produced by the reductive tricarboxylic acid (rTCA) cycle are possibly a biosynthetic core of initial life, although several steps such as the reductive kinetics of oxaloacetate (OAA) to malate (MA) are problematic by conventional chemical routes. In this context, we studied the kinetics of this reaction as promoted by ZnS mineral photoelectrochemistry. The quantum efficiency φMA of MA production from the photoelectrochemical reduction of OAA followed φMA=0.13 [OAA] (2.1×10-3+[OAA])-1 and was independent of temperature (5 to 50°C). To evaluate the importance of this forward rate under a prebiotic scenario, we also studied the temperature-dependent rate of the backward thermal decarboxylation of OAA to pyruvate (PA), which followed an Arrhenius behavior as log (k-2)=11.74 4956/T, where k-2 is in units of s-1. These measured rates were employed in conjunction with the indirectly estimated carboxylation rate of PA to OAA to assess the possible importance of mineral photoelectrochemistry in the conversion of OAA to MA under several scenarios of prebiotic conditions on early Earth. As an example, our analysis shows that there is 90% efficiency with a forward velocity of 3 yr/cycle for the OAA→MA step of the rTCA cycle at 280 K. Efficiency and velocity both decrease for increasing temperature. These results suggest high viability for mineral photoelectrochemistry as an enzyme-free engine to drive the rTCA cycle through the early aeons of early Earth, at least for the investigated OAA→MA step.

  10. Amino acid substitutions in malate dehydrogenases of piezophilic bacteria isolated from intestinal contents of deep-sea fishes retrieved from the abyssal zone.

    PubMed

    Saito, Rie; Kato, Chiaki; Nakayama, Akihiko

    2006-02-01

    To examine the occurrence in other deep-sea bacteria of two amino acid substitutions (Ala-180 and His-229) in malate dehydrogenase (MDH) found previously in the deep-sea piezophilic Moritella sp. strain 2D2, we cloned and sequenced MDH genes of deep-sea piezophilic Moritella and Shewanella strains isolated from intestinal contents of deep-sea fishes, as well as other Moritella species from deep-sea water and sediments: M. marina, M. japonica, and M. yayanosii. The piezophilic Moritella strains had a Val residue or an Ala residue at position 180 and all the Moritella strains except for one had a His residue at position 229. However, four piezophilic-strain-specific substitutions at positions 103, 111, 229, and 283 were found to be completely conserved in the MDH of the intestinal Moritella strains of deep-sea fishes, indicating the substitutions may be habitat-specific. The piezophilic Shewanella strains had a Val residue and a Gln residue at positions 180 and 229, respectively. However, the MDHs of the Shewanella strains had five piezophilic-strain-specific substitutions at positions 61, 65, 107, 161, and 202. Therefore, the enzymatic strategies for responding to deep-sea high pressure environments of the MDHs between the genera Moritella and Shewanella are potentially different. Moreover, homology modeling shows these substitutions found in the MDHs of both genera except for position 229 in the subunit interface are located on the exposed region of the MDH molecules, indicating the substitutions may be related to the hydration state of the molecules. PMID:16598154

  11. Activation of NADP-Malate Dehydrogenase, Pyruvate,Pi Dikinase, and Fructose 1,6-Bisphosphatase in Relation to Photosynthetic Rate in Maize 1

    PubMed Central

    Usuda, Hideaki; Ku, Maurice S. B.; Edwards, Gerald E.

    1984-01-01

    The activity and extent of light activation of three photosynthetic enzymes, pyruvate,Pi dikinase, NADP-malate dehydrogenase (NADP-MDH), and fructose 1,6-bisphosphatase (FBPase), were examined in maize (Zea mays var Royal Crest) leaves relative to the rate of photosynthesis during induction and under varying light intensities. There was a strong light activation of NADP-MDH and pyruvate,Pi dikinase, and light also activated FBPase 2- to 4-fold. During the induction period for whole leaf photosynthesis at 30°C under high light, the time required to reach half-maximum activation for all three enzymes was only 1 minute or less. After 2.5 minutes of illumination the enzymes were fully activated, while the photosynthetic rate was only at half-maximum activity, indicating that factors other than enzyme activation limit photosynthesis during the induction period in C4 plants. Under steady state conditions, the light intensity required to reach half-maximum activation of the three enzymes was similar (300-400 microEinsteins per square meter per second), while the light intensity required for half-maximum rates of photosynthesis was about 550 microEinsteins per square meter per second. The light activated levels of NADP-MDH and FBPase were well in excess of the in vivo activities which would be required during photosynthesis, while maximum activities of pyruvate,Pi dikinase were generally just sufficient to accommodate photosynthesis, suggesting the latter may be a rate limiting enzyme. There was a large (5-fold) light activation of FBPase in isolated bundle sheath strands of maize, whereas there was little light activation of the enzyme in isolated mesophyll protoplasts. In mesophyll protoplasts the enzyme was largely located in the cytoplasm, although there was a low amount of light-activated enzyme in the mesophyll chloroplasts. The results suggest the chloroplastic FBPase in maize is primarily located in the bundle sheath cells. PMID:16663806

  12. Long term intensive exercise training leads to a higher plasma malate/lactate dehydrogenase (M/L) ratio and increased level of lipid mobilization in horses.

    PubMed

    Li, Gebin; Lee, Peter; Mori, Nobuko; Yamamoto, Ichiro; Arai, Toshiro

    2012-06-01

    Continuous high intensity training may induce alterations to enzyme activities related to glucose and lipid metabolism in horses. In our study, five Thoroughbred race horses (3 male and 2 female, avg age=5 yrs old) were compared against five riding horses (1 male, 1 female, 3 gelding, avg age=13 yrs old) in terms of energy metabolism, by examining plasma malate (MDH) and lactate (LDH) dehydrogenase activities and M/L ratio. MDH is involved in NADH and ATP generation, whereas LDH can convert NADH back into NAD(+) for ATP generation. An increase in plasma M/L ratio can reflect heightened energy metabolism in the liver and skeletal muscle of horses adapted to continuous intensive exercise. Moreover, plasma lipid metabolism analytes (adiponectin, NEFA, total cholesterol (T-Cho), and triglycerides (TG)) can reflect changes to lipolysis rate, which can also indicate a change in energy metabolism. Overall, race horses demonstrated increased MDH and LDH activity in plasma (4x and 2x greater, respectively), in addition to a plasma M/L ratio twice as high as that of riding horses (2.0 vs 1.0). In addition, race horses also demonstrated significantly higher levels of plasma NEFA (50% greater), TG (2x greater), and T-Cho (20% greater) as compared to riding horses. Therefore, race horse muscles may have adapted to prolonged high intensity endurance exercise by gaining a higher oxidative capacity and an increased capacity for fat utilization as an energy source, resulting in heightened energy metabolism and increased rate of lipid mobilization.

  13. Calcium-regulation of mitochondrial respiration maintains ATP homeostasis and requires ARALAR/AGC1-malate aspartate shuttle in intact cortical neurons.

    PubMed

    Llorente-Folch, Irene; Rueda, Carlos B; Amigo, Ignacio; del Arco, Araceli; Saheki, Takeyori; Pardo, Beatriz; Satrústegui, Jorgina

    2013-08-28

    Neuronal respiration is controlled by ATP demand and Ca2+ but the roles played by each are unknown, as any Ca2+ signal also impacts on ATP demand. Ca2+ can control mitochondrial function through Ca2+-regulated mitochondrial carriers, the aspartate-glutamate and ATP-Mg/Pi carriers, ARALAR/AGC1 and SCaMC-3, respectively, or in the matrix after Ca2+ transport through the Ca2+ uniporter. We have studied the role of Ca2+ signaling in the regulation of mitochondrial respiration in intact mouse cortical neurons in basal conditions and in response to increased workload caused by increases in [Na+]cyt (veratridine, high-K+ depolarization) and/or [Ca2+]cyt (carbachol). Respiration in nonstimulated neurons on 2.5-5 mm glucose depends on ARALAR-malate aspartate shuttle (MAS), with a 46% drop in aralar KO neurons. All stimulation conditions induced increased OCR (oxygen consumption rate) in the presence of Ca2+, which was prevented by BAPTA-AM loading (to preserve the workload), or in Ca2+-free medium (which also lowers cell workload). SCaMC-3 limits respiration only in response to high workloads and robust Ca2+ signals. In every condition tested Ca2+ activation of ARALAR-MAS was required to fully stimulate coupled respiration by promoting pyruvate entry into mitochondria. In aralar KO neurons, respiration was stimulated by veratridine, but not by KCl or carbachol, indicating that the Ca2+ uniporter pathway played a role in the first, but not in the second condition, even though KCl caused an increase in [Ca2+]mit. The results suggest a requirement for ARALAR-MAS in priming pyruvate entry in mitochondria as a step needed to activate respiration by Ca2+ in response to moderate workloads.

  14. Large scientific releases

    SciTech Connect

    Pongratz, M.B.

    1981-01-01

    The motivation for active experiments in space is considered, taking into account the use of active techniques to obtain a better understanding of the natural space environment, the utilization of the advantages of space as a laboratory to study fundamental plasma physics, and the employment of active techniques to determine the magnitude, degree, and consequences of artificial modification of the space environment. It is pointed out that mass-injection experiments in space plasmas began about twenty years ago with the Project Firefly releases. Attention is given to mass-release techniques and diagnostics, operational aspects of mass release active experiments, the active observation of mass release experiments, active perturbation mass release experiments, simulating an artificial modification of the space environment, and active experiments to study fundamental plasma physics.

  15. Temperature sensitivities of cytosolic malate dehydrogenases from native and invasive species of marine mussels (genus Mytilus): sequence-function linkages and correlations with biogeographic distribution.

    PubMed

    Fields, Peter A; Rudomin, Emily L; Somero, George N

    2006-02-01

    The blue mussel Mytilus galloprovincialis, a native of the Mediterranean Sea, has invaded the west coast of North America in the past century, displacing the native blue mussel, Mytilus trossulus, from most of its former habitats in central and southern California. The invasive success of M. galloprovincialis is conjectured to be due, in part, to physiological adaptations that enable it to outperform M. trossulus at high temperatures. We have examined the structure and function of the enzyme cytosolic malate dehydrogenase (cMDH) from these species, as well as from the more distantly related ribbed mussel, Mytilus californianus, to characterize the effects of temperature on kinetic properties thought to exhibit thermal adaptation. The M. trossulus cMDH ortholog differs from the other cMDHs in a direction consistent with cold adaptation, as evidenced by a higher and more temperature-sensitive Michaelis-Menten constant for the cofactor NADH (Km(NADH)). This difference results from minor changes in sequence: the M. trossulus ortholog differs from the M. galloprovincialis ortholog by only two substitutions in the 334 amino acid monomer, and the M. californianus and M. trossulus orthologs differ by five substitutions. In each case, only one of these substitutions is non-conservative. To test the effects of individual substitutions on kinetic properties, we used site-directed mutagenesis to create recombinant cMDHs. Recombinant wild-type M. trossulus cMDH (rWT) has high Km(NADH) compared with mutants incorporating the non-conservative substitutions found in M. californianus and M. galloprovincialis - V114H and V114N, respectively - demonstrating that these mutations are responsible for the differences found in substrate affinity. Turnover number (kcat) is also higher in rWT compared with the two mutants, consistent with cold adaptation in the M. trossulus ortholog. Conversely, rWT and V114H appear more thermostable than V114N. Based on a comparison of Km(NADH) and kcat

  16. Rad-Release

    ScienceCinema

    None

    2016-07-12

    The R&D 100 Award winning Rad-Release Chemical Decontamination Technology is a highly effective (up to 99% removal rate), affordable, patented chemical-foam-clay decontamination process tailored to specific radiological and metal contaminants, which is applicable to a wide variety of substrates. For more information about this project, visit http://www.inl.gov/rd100/2011/rad-release/

  17. Rad-Release

    SciTech Connect

    2011-01-01

    The R&D 100 Award winning Rad-Release Chemical Decontamination Technology is a highly effective (up to 99% removal rate), affordable, patented chemical-foam-clay decontamination process tailored to specific radiological and metal contaminants, which is applicable to a wide variety of substrates. For more information about this project, visit http://www.inl.gov/rd100/2011/rad-release/

  18. Cytochrome c release from rat liver mitochondria is compromised by increased saturated cardiolipin species induced by sucrose feeding.

    PubMed

    Ruiz-Ramírez, Angélica; Barrios-Maya, Miguel-Angel; López-Acosta, Ocarol; Molina-Ortiz, Dora; El-Hafidi, Mohammed

    2015-11-01

    Cytochrome c release from mitochondria has been described to be related to reactive oxygen species (ROS) generation. With ROS generation being increased in fatty liver from sucrose-fed (SF) rats, we hypothesized that cytochrome c release might be positively associated with H2O2 generation from SF mitochondria. Surprisingly, cytochrome c release from mitochondria of SF liver was found to be significantly lower compared with control (C) mitochondria oxidizing pyruvate/malate or succinate. Exposure of mitochondria to exogenous superoxide radical generated by the xanthine/xanthine oxidase system elicits a dose-response cytochrome c release in both control and SF mitochondria, but cytochrome c release remains lower in SF mitochondria compared with C mitochondria. Furthermore, the addition of ebselen, PEG-catalase, or catalase, a H2O2 scavenger, significantly reduces cytochrome c release from C and SF mitochondria. Our results suggest that both intra- and extramitochondrial H2O2 are involved in cytochrome c release, but the persisting difference between C and SF levels can be attributed to the differences in cardiolipin compositions. Indeed, the ratio of palmitic acid-rich cardiolipin species was found to be increased in lipid membrane from SF mitochondria compared with C mitochondria, whereas that of linoleic acid-rich cardiolipin species was found decreased. In addition, the content of tafazzin, a protein responsible for cardiolipin remodeling, was decreased in SF mitochondria. Therefore, we conclude that the changes observed in the composition of cardiolipin molecular species in SF mitochondria may be involved in cytochrome c interaction with mitochondrial inner membrane lipid and in its reduced release from SF mitochondria.

  19. Advanced release technologies program

    NASA Technical Reports Server (NTRS)

    Purdy, Bill

    1994-01-01

    The objective of the ARTS program was to develop lighter and less expensive spacecraft ordnance and release systems that answer to the requirements of a wide variety of spacecraft applications. These improvements were to be evaluated at the spacecraft system level, as it was determined that there were substantial system-level costs associated with the present ordnance and release subsystems. New, better devices were to be developed, then flight qualified, then integrated into a flight experiment in order to prove the reliability required for their subsequent use on high-reliability spacecraft. The secondary goal of the program was to quantify the system-level benefits of these new subsystems based upon the development program results. Three non-explosive release mechanisms and one laser-diode-based ordnance system were qualified under the program. The release devices being developed were required to release high preloads because it is easier to scale down a release mechanism than to scale it up. The laser initiator developed was required to be a direct replacement for NASA Standard Initiators, since these are the most common initiator in use presently. The program began in October, 1991, with completion of the flight experiment scheduled for February, 1994. This paper provides an overview of the ARTS program, discusses the benefits of using the ARTS components, introduces the new components, compares them with conventional systems and each other, and provides recommendations on how best to implement them.

  20. Fluid operated quick release mechanism

    NASA Technical Reports Server (NTRS)

    Brown, R. A.

    1972-01-01

    Gas operated release mechanism releases load by fluid pressure to provide positive action quick release. Method can be used with large loads and is useful in repetitive cycling functions where shear pins and similar devices would be cumbersome.

  1. Aluminum induces tau aggregation in vitro but not in vivo.

    PubMed

    Mizoroki, Tatsuya; Meshitsuka, Shunsuke; Maeda, Sumihiro; Murayama, Miyuki; Sahara, Naruhiko; Takashima, Akihiko

    2007-07-01

    Etiological studies suggest that aluminum (Al) intake might increase an individual's risk of developing Alzheimer's disease (AD). Biochemical analysis data on the effects of Al, however, are inconsistent. Hence, the pathological involvement of Al in AD remains unclear. If Al is involved in AD, then it is reasonable to hypothesize that Al might be involved in the formation of either amyloid plaques or neurofibrillary tangles (NFTs). Here, we investigated whether Al might be involved in NFT formation by using an in vitro tau aggregation paradigm, a tau-overexpressing neuronal cell line (N2a), and a tau-overexpressing mouse model. Although Al induced tau aggregation in a heparin-induced tau assembly assay, these aggregates were neither thioflavin T positive nor did they resemble tau fibrils seen in human AD brains. With cell lysates from stable cell lines overexpressing tau, the accumulation of SDS-insoluble tau increased when the lysates were treated with at least 100 muM Al-maltolate. Yet Al-maltolate caused illness or death in transgenic mice overexpressing human tau and in non-transgenic littermates well before the Al concentration in the brain reached 100 muM. These results indicate that Al has no direct link to AD pathology.

  2. Aluminum Induces Oxidative Stress Genes in Arabidopsis thaliana1

    PubMed Central

    Richards, Keith D.; Schott, Eric J.; Sharma, Yogesh K.; Davis, Keith R.; Gardner, Richard C.

    1998-01-01

    Changes in gene expression induced by toxic levels of Al were characterized to investigate the nature of Al stress. A cDNA library was constructed from Arabidopsis thaliana seedlings treated with Al for 2 h. We identified five cDNA clones that showed a transient induction of their mRNA levels, four cDNA clones that showed a longer induction period, and two down-regulated genes. Expression of the four long-term-induced genes remained at elevated levels for at least 48 h. The genes encoded peroxidase, glutathione-S-transferase, blue copper-binding protein, and a protein homologous to the reticuline:oxygen oxidoreductase enzyme. Three of these genes are known to be induced by oxidative stresses and the fourth is induced by pathogen treatment. Another oxidative stress gene, superoxide dismutase, and a gene for Bowman-Birk protease inhibitor were also induced by Al in A. thaliana. These results suggested that Al treatment of Arabidopsis induces oxidative stress. In confirmation of this hypothesis, three of four genes induced by Al stress in A. thaliana were also shown to be induced by ozone. Our results demonstrate that oxidative stress is an important component of the plant's reaction to toxic levels of Al. PMID:9449849

  3. Pomegranate peel attenuates aluminum-induced hepatorenal toxicity.

    PubMed

    Abdel Moneim, Ahmed E; Othman, Mohamed S; Mohmoud, Sahar M; El-Deib, Kamal M

    2013-10-01

    The present study was undertaken to determine the potential role of methanolic extract of pomegranate peel (MEPP) in modulating aluminum chloride (AlCl3) induced hepatorenal toxicity in female rats. The effect of MEPP (200 mg/kg bwt) on AlCl3 (34 mg/kg bwt) induced hepatorenal toxicity, accumulation of aluminum (Al), hepatorenal functions and oxidant/antioxidant status of liver and kidney were determined. The changes of liver and kidney structures were investigated with hematoxyline and eosin, in addition, the anti-apoptotic effect of MEPP was analyzed by immunohistochemistry. The present study showed an indication of carcinogenicity in the AlCl3 treated group represented by an increase in tumor necrosis factor-α and angiogenin and inflammation by inducing an increase in prostaglandin E2 and F2α. MEPP protected liver and kidney through reduce the Al accumulation, stimulated antioxidant activities and elevated the anti-apoptotic protein namely Bcl-2. Therefore, these results indicated that the methanolic extract of pomegranate peel has beneficial influences and could be able to inhibit Al-induced oxidative stress and histopathological alternations in liver and kidney of female rats, and these effects may be related to anti-apoptotic and antioxidant activities. PMID:23837566

  4. Altitude release mechanism

    DOEpatents

    Kulhanek, Frank C.

    1977-01-01

    An altitude release mechanism for releasing a radiosonde or other measuring instrument from a balloon carrying it up into the atmosphere includes a bottle partially filled with water, a tube sealed into the bottle having one end submerged in the water in the bottle and the free end extending above the top of the bottle and a strip of water-disintegrable paper held within the free end of the tube linking the balloon to the remainder of the package. As the balloon ascends, the lowered atmospheric air pressure causes the air in the bottle to expand, forcing the water in the bottle up the tubing to wet and disintegrate the paper, releasing the package from the balloon.

  5. Controlled-release microchips.

    PubMed

    Sharma, Sadhana; Nijdam, A Jasper; Sinha, Piyush M; Walczak, Robbie J; Liu, Xuewu; Cheng, Mark M-C; Ferrari, Mauro

    2006-05-01

    Efficient drug delivery remains an important challenge in medicine: continuous release of therapeutic agents over extended time periods in accordance with a predetermined temporal profile; local delivery at a constant rate to the tumour microenvironment to overcome much of the systemic toxicity and to improve antitumour efficacy; improved ease of administration, and increasing patient compliance required are some of the unmet needs of the present drug delivery technology. Microfabrication technology has enabled the development of novel controlled-release microchips with capabilities not present in the current treatment modalities. In this review, the current status and future prospects of different types of controlled-release microchips are summarised and analysed with reference to microneedle-based microchips, as well as providing an in-depth focus on microreservoir-based and nanoporous microchips.

  6. Benzene release. status report

    SciTech Connect

    Dworjanyn, L.O.; Rappe, K.G.; Gauglitz, P.A.

    1997-11-04

    Scoping benzene release measurements were conducted on 4 wt percent KTPB `DEMO` formulation slurry using a round, flat bottomed 100-mL flask containing 75 mL slurry. The slurry was agitated with a magnetic stirrer bar to keep the surface refreshed without creating a vortex. Benzene release measurements were made by purging the vapor space at a constant rate and analyzing for benzene by gas chromatography with automatic data acquisition. Some of the data have been rounded or simplified in view of the scoping nature of this study.

  7. DSCOVR Public Release Statement

    Atmospheric Science Data Center

    2016-08-04

    ... Book .    NOAA will release data from the space weather instruments on July 27 th . The data, as well as space weather forecasts with a 30-45 minute lead-time will be available via the Space ...

  8. Release of OLe peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OLe is a high oleic Spanish-type peanut that has excellent yield and enhanced Sclerotinia blight and pod rot resistance when compared to other high oleic Spanish cultivars. The purpose for releasing OLe is to provide peanut producers with a true Spanish peanut that is high oleic and has enhanced yi...

  9. Releasable Asbestos Field Sampler

    EPA Science Inventory

    Asbestos aerosolization (or releasability) is the potential for fibrous asbestos structures that are present in a material or on a solid surface to become airborne when the source is disturbed by human activities or natural forces. In turn, the magnitude of the airborne concentra...

  10. DSCOVR Public Release Statement

    Atmospheric Science Data Center

    2016-09-26

    ... Data and Information Wednesday, July 20, 2016 The Deep Space Climate Observatory (DSCOVR) is a NOAA/NASA mission located near the ... Format Control Book. NOAA will release data from the space weather instruments on July 27th. The data, as well as space weather ...

  11. Release the Prisoners Game

    ERIC Educational Resources Information Center

    Van Hecke, Tanja

    2011-01-01

    This article presents the mathematical approach of the optimal strategy to win the "Release the prisoners" game and the integration of this analysis in a math class. Outline lesson plans at three different levels are given, where simulations are suggested as well as theoretical findings about the probability distribution function and its mean…

  12. Release Fraction Evaluation

    SciTech Connect

    Bamberger, Judith A.; Glissmeyer, John A.

    2004-01-01

    This document presents results of experiments conducted to measure release fractions during certain tank retrieval processes. The tests were performed in a 1/4 scale model of a waste storage tank. The retrieval processes simulated were: (1) Discharging liquid or slurry from the mouth of a vertically oriented two-in. Schedule 40 pipe. The discharging material was in free-fall from the mouth of the pipe near the top of the tank into a liquid or slurry pool at the bottom of the tank. (2) The jet from a 9/16-in.-diameter nozzle transferring liquid or slurry waste from one side of the tank to the other. The discharging liquid was aimed at the opposite side of the tank from the nozzle and either impacted the tank wall or fell into a liquid or slurry pool in the bottom of the tank. (3) A high pressure fan jet of liquid striking a steel plate or simulated waste from a stand-off distance of a few inches. For each process, a water-soluble fluorescent dye was added to the liquid fraction as a tracer. Kaolin clay was used to represent the solids. The tank was covered and there was no forced ventilation in the tank during the tests. Six air samples were collected during each test. The air samples were collected at fixed positions in the tank. The air sample filters were dried and weighed to determine the solids collection. The fluorescent dye was then leached from each filter and quantified with a fluorometer to determine the collection of liquid. Samples of the slurry and liquid simulants were also collected to determine the quantities of simulant used in each test. To calculate the release fraction, the quantity collected on each air sample was adjusted for the fraction of the tank volume sampled and divided by the quantity of material exposed in the simulation. The method was not as sensitive for the solids content as it was for the liquid content, but in those instances where a solids release fraction was determined, it was in relatively good agreement with that of the

  13. Effects of a first exposure to ethanol on the compositions of neutral and polar lipids in Euglena gracilis Z, taken as a hepatic cell model: equilibration by citrulline-malate.

    PubMed

    Thuillier-Bruston, F; Briand, J; Laval-Martin, D

    1990-10-01

    In comparison to the lipid composition of Euglena cells fed with lactate, a first exposure of the cells to ethanol favors the production of neutral lipids containing mainly unsaturated fatty acids. The ethanol diminishes drastically the proportion of PC and weakly that of PE. In contrast, it increases slightly the proportion of DPG. The ethanol induces important changes in the fatty acid distributions of each lipid class, suggesting modifications of the elongation-desaturation system. On the one hand the proportion of unsaturated fatty acids is increased and, on the other hand, the last double bond is predominantly situated in the delta 6 position in place of delta 3. The addition of the complex citrulline-malate corrects most of these changes. PMID:2252617

  14. Releasable locking mechanisms

    NASA Technical Reports Server (NTRS)

    Ahmed, Rafiq (Inventor); Wingate, Robert J. (Inventor)

    2005-01-01

    In the aerospace field spacecraft components are held together by separation systems until a specific time when they must be separated or deployed. Customarily a threaded joining bolt engages one of the components to be joined, and a threaded nut is placed on that bolt against the other component so they can be drawn together by a releasable locking assembly. The releasable locking assembly herein includes a plunger having one end coupled to one end of a plunger bolt. The other end is flanged to abut and compress a coil spring when the plunger is advanced toward the interface plane between the two components. When the plunger is so advanced toward the interface plane, the end of the plunger bolt can be connected to the joining bolt. Thus during retraction the joining bolt is drawn to one side of the interface plane by the force of the expanding spring.

  15. Atmospheric Release Advisory Capability

    SciTech Connect

    Dickerson, M.H.; Gudiksen, P.H.; Sullivan, T.J.

    1983-02-01

    The Atmospheric Release Advisory Capability (ARAC) project is a Department of Energy (DOE) sponsored real-time emergency response service available for use by both federal and state agencies in case of a potential or actual atmospheric release of nuclear material. The project, initiated in 1972, is currently evolving from the research and development phase to full operation. Plans are underway to expand the existing capability to continuous operation by 1984 and to establish a National ARAC Center (NARAC) by 1988. This report describes the ARAC system, its utilization during the past two years, and plans for its expansion during the next five to six years. An integral part of this expansion is due to a very important and crucial effort sponsored by the Defense Nuclear Agency to extend the ARAC service to approximately 45 Department of Defense (DOD) sites throughout the continental US over the next three years.

  16. Releasable Locking Mechanisms

    NASA Technical Reports Server (NTRS)

    Ahmed, Rafiq (Inventor); Wingate, Robert J. (Inventor)

    2005-01-01

    In the aerospace field spacecraft components are held together by separation systems until a specific time when they must be separated or deployed. Customarily a threaded joining bolt engages one of the components to be joined, and a threaded nut is placed on that bolt against the other component so they can be drawn together by a releasable locking assembly. The releasable locking assembly herein includes a plunger having one end coupled to one end of a plunger bolt. The other end is flanged to abut and compress a coil spring when the plunger is advanced toward the interface plane between the two components. When the plunger is so advanced toward the interface plane, the end of the plunger bolt can be connected to the joining bolt. Thus during retraction the joining bolt is drawn to one side of the interface plane by the force of the expanding spring.

  17. Slow-release fertilizer

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Golden, D. C. (Inventor)

    1992-01-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  18. Slow-release fertilizer

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  19. Cryogenic hydrogen release research.

    SciTech Connect

    LaFleur, Angela Christine

    2015-12-01

    The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  20. Clinton releases oceans report

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    U.S. President Bill Clinton is trying to beat the clock on the January 20 close of his administration by maintaining a flurry of activity on resource and conservation issues.During a December 4 speech in Washington, D.C., he released a broad-ranging report by the Presidents Panel on Ocean Exploration, entitled “Discovering Earth's Final Frontier: A U.S. Strategy for Ocean Exploration.”

  1. EIA new releases

    SciTech Connect

    Not Available

    1994-12-01

    This report was prepared by the Energy Information Administration. It contains news releases on items of interest to the petroleum, coal, nuclear, electric and alternate fuels industries ranging from economic outlooks to environmental concerns. There is also a listing of reports by industry and an energy education resource listing containing sources for free or low-cost energy-related educational materials for educators and primary and secondary students.

  2. Slow-release fertilizer

    NASA Astrophysics Data System (ADS)

    Ming, Douglas W.; Golden, D. C.

    1992-10-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  3. Preload release mechanism

    NASA Technical Reports Server (NTRS)

    Generoli, Robert M. (Inventor); Young, Harry J. (Inventor)

    1995-01-01

    This invention relates to a preload release mechanism comprising a preload spring assembly adapted to apply a preload to a first connector member which is mounted on a support structure and adapted for connection with a second connector member on an object. The assembly comprises telescoped bushings and a preload spring. A tubular shaft extends through the spring assembly and openings in the first connector member and support structure, on which it is clamped. A plunger rod in the shaft is provided with a tip end and a recess in the rod near the other end thereof. A retainer precludes passage of the rod through the shaft in one direction and an end cap closes the bore of the shaft at the other end and provides a shoulder which extends radially of the shaft. A plunger return spring biases the plunger rod against the plunger retainer with the plunger tip protruding from the shaft and a spring assembly return spring engages at its ends the shoulder of the end cap and one end of the spring assembly. Detents received in lateral openings in the tubular shaft are held captive by the plunger rod and one end of the spring assembly to lock the spring assembly on the tubular shaft and apply a preload to the first connector member. Upon completion of the connection, detents and spring assembly are released by plunger contact with the object to be connected, thereby releasing the preload while the connection is maintained.

  4. Contact: Releasing the news

    NASA Astrophysics Data System (ADS)

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  5. Triggered Release from Polymer Capsules

    SciTech Connect

    Esser-Kahn, Aaron P.; Odom, Susan A.; Sottos, Nancy R.; White, Scott R.; Moore, Jeffrey S.

    2011-07-06

    Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

  6. Sustained-release, extended-release, and other time-release formulations in neuropsychiatry.

    PubMed

    Andrade, Chittaranjan

    2015-08-01

    Pills and capsules may release their contents within minutes of ingestion; these are immediate-release formulations. Pills and capsules may also release their contents after a time lag, or a little at a time, or in some other predetermined way; these are time-release formulations. Many drugs in psychiatry have been time-release formulated to reduce their local adverse effects in the gastrointestinal tract, to reduce adverse effects associated with peak blood levels, or to artificially extend their half-life. Time-release formulations are associated with the added advantages of convenience of dosing, improved compliance, and less fluctuation in blood levels across the course of the day. A disadvantage of time-release formulations is that they may be incompletely absorbed; this is a serious issue in patients with acute or chronic intestinal hurry disorders, such as gastroenteritis or irritable bowel syndrome. Time-release formulations may also be more expensive than immediate-release formulations.

  7. Gas releases from salt

    SciTech Connect

    Ehgartner, B.; Neal, J.; Hinkebein, T.

    1998-06-01

    The occurrence of gas in salt mines and caverns has presented some serious problems to facility operators. Salt mines have long experienced sudden, usually unexpected expulsions of gas and salt from a production face, commonly known as outbursts. Outbursts can release over one million cubic feet of methane and fractured salt, and are responsible for the lives of numerous miners and explosions. Equipment, production time, and even entire mines have been lost due to outbursts. An outburst creates a cornucopian shaped hole that can reach heights of several hundred feet. The potential occurrence of outbursts must be factored into mine design and mining methods. In caverns, the occurrence of outbursts and steady infiltration of gas into stored product can effect the quality of the product, particularly over the long-term, and in some cases renders the product unusable as is or difficult to transport. Gas has also been known to collect in the roof traps of caverns resulting in safety and operational concerns. The intent of this paper is to summarize the existing knowledge on gas releases from salt. The compiled information can provide a better understanding of the phenomena and gain insight into the causative mechanisms that, once established, can help mitigate the variety of problems associated with gas releases from salt. Outbursts, as documented in mines, are discussed first. This is followed by a discussion of the relatively slow gas infiltration into stored crude oil, as observed and modeled in the caverns of the US Strategic Petroleum Reserve. A model that predicts outburst pressure kicks in caverns is also discussed.

  8. Riola release report

    SciTech Connect

    Woodward, E.C.

    1983-08-04

    Eleven hours after execution of the Riola Event (at 0826 PDT on 25 September 1980) in hole U2eq of the Nevada Test Site (NTS), a release of radioactivity began. When the seepage stopped at about noon the following day, up to some 3200 Ci of activity had been dispersed by light variable winds. On 26 September, examination of the geophone records showed six hours of low-level, but fairly continuous, activity before the release. Electrical measurements indicated that most cables were still intact to a depth below the stemming platform. A survey of the ground zero area showed that the seepage came through cracks between the surface conductor and the pad, through cracks in the pad, and through a crack adjacent to the pad around the mousehole (a small hole adjacent to the emplacement hole). To preclude undue radiation exposure or injury from a surprise subsidence, safety measures were instituted. Tritium seepage was suffucient to postpone site activities until a box and pipeline were emplaced to contain and remove the gas. Radiation release modeling and calculations were generally consistent with observations. Plug-hole interaction calculations showed that the alluvium near the bottom of the plug may have been overstressed and that improvements in the design of the plug-medium interface can be made. Experimental studies verified that the surface appearance of the plug core was caused by erosion, but, assuming a normal strength for the plug material, that erosion alone could not account for the disappearance of such a large portion of the stemming platform. Samples from downhole plug experiments show that the plug may have been considerably weaker than had been indicted by quality assurance (QA) samples. 19 references, 32 figures, 10 tables.

  9. Birth control - slow release methods

    MedlinePlus

    ... ovaries from releasing an egg. Releasing egg during menstrual cycle is called ovulation. They do this by changing ... implants are likely to get pregnant. Your regular menstrual cycles should return within 3 to 4 weeks after ...

  10. A controlled-release microchip.

    PubMed

    Santini, J T; Cima, M J; Langer, R

    1999-01-28

    Much previous work in methods of achieving complex drug-release patterns has focused on pulsatile release from polymeric materials in response to specific stimuli, such as electric or magnetic fields, exposure to ultrasound, light or enzymes, and changes in pH or temperature. An alternative method for achieving pulsatile release involves using microfabrication technology to develop active devices that incorporate micrometre-scale pumps, valves and flow channels to deliver liquid solutions. Here we report a solid-state silicon microchip that can provide controlled release of single or multiple chemical substances on demand. The release mechanism is based on the electrochemical dissolution of thin anode membranes covering microreservoirs filled with chemicals in solid, liquid or gel form. We have conducted proof-of-principle release studies with a prototype microchip using gold and saline solution as a model electrode material and release medium, and we have demonstrated controlled, pulsatile release of chemical substances with this device.

  11. Hydrogen release behavior.

    SciTech Connect

    LaChance, Jeffrey L.; Dedrick, Daniel E.; Keller, Jay O.; Evans, Gregory Herbert; Houf, William G.; Winters, William Stanley, Jr.; Ruggles, A.; Zhang, J.

    2010-04-01

    The summary of this presentation is: (1) Barrier walls are used to reduce setbacks by factor of 2; (2) We found no ignition-timing vs. over-pressure sensitivities for jet flow obstructed by barrier walls; (3) Cryogenic vapor cloud model indicates hazard length scales exceed the room-temperature release; validation experiments are required to confirm; (4) Light-up maps developed for lean limit ignition; flammability factor model provides good indication of ignition probability; and (5) Auto-ignition is enhanced by blunt-body obstructions - increases gas temperature and promotes fuel/air mixing.

  12. Arthroscopic Posteromedial Capsular Release.

    PubMed

    Dean, Chase S; Chahla, Jorge; Mikula, Jacob D; Mitchell, Justin J; LaPrade, Robert F

    2016-06-01

    Post-traumatic or postsurgical flexion contractures of the knee can significantly limit function and lead to gait abnormalities. In this setting, interventions to regain full extension may include bracing, physical therapy, and open or arthroscopic surgery. Open surgical approaches to restore full motion often demand extensive recovery and promote further adhesions and loss of motion, which has led to the advent of arthroscopic techniques to address these pathologies. We present a safe, effective, and reproducible arthroscopic technique for posteromedial capsular release to address knee flexion contractures. PMID:27656368

  13. Source of released carbon fibers

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1979-01-01

    The potential for the release of carbon fibers from aircraft crashes/fires is addressed. Simulation of the conditions of aircraft crash fires in order to predict the quantities and forms of fibrous materials which might be released from civilian aircraft crashes/fires is considered. Figures are presented which describe some typical fiber release test activities together with some very preliminary results of those activities. The state of the art of carbon fiber release is summarized as well as some of the uncertainties concerning accidental fiber release.

  14. Draft Wetlands Rule Released

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2006-04-01

    The U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers released on 28 March a draft of a new rule to guide compensatory mitigation for when wetlands are unavoidably lost due to development. However, whether the rule is successful in preventing a net loss in wetlands will depend largely on its implementation, according to two wetlands scientists who evaluated the issue for the U.S. National Research Council (NRC) in 2001. Under the federal Clean Water Act, developers who seek to build on wetlands must compensate for any wetlands loss if they are unable to avoid or minimize the loss. Such compensation is covered under the newly proposed compensatory mitigation rule. Benjamin Grumbles, EPA assistant administrator for water, called the rule an ``innovative new standard that will accelerate the pace of wetlands conservation and restoration.''

  15. Quick release engine cylinder

    DOEpatents

    Sunnarborg, Duane A.

    2000-01-01

    A quick release engine cylinder allows optical access to an essentially unaltered combustion chamber, is suitable for use with actual combustion processes, and is amenable to rapid and repeated disassembly and cleaning. A cylinder member, adapted to constrain a piston to a defined path through the cylinder member, sealingly engages a cylinder head to provide a production-like combustion chamber. A support member mounts with the cylinder member. The support-to-cylinder mounting allows two relationships therebetween. In the first mounting relationship, the support engages the cylinder member and restrains the cylinder against the head. In the second mounting relationship, the cylinder member can pass through the support member, moving away from the head and providing access to the piston-top and head.

  16. Attentional priming releases crowding.

    PubMed

    Kristjánsson, Arni; Heimisson, Pétur Rúnar; Róbertsson, Gunnar Freyr; Whitney, David

    2013-10-01

    Views of natural scenes unfold over time, and objects of interest that were present a moment ago tend to remain present. While visual crowding places a fundamental limit on object recognition in cluttered scenes, most studies of crowding have suffered from the limitation that they typically involved static scenes. The role of temporal continuity in crowding has therefore been unaddressed. We investigated intertrial effects upon crowding in visual scenes, showing that crowding is considerably diminished when objects remain constant on consecutive visual search trials. Repetition of both the target and distractors decreases the critical distance for crowding from flankers. More generally, our results show how object continuity through between-trial priming releases objects that would otherwise be unidentifiable due to crowding. Crowding, although it is a significant bottleneck on object recognition, can be mitigated by statistically likely temporal continuity of the objects. Crowding therefore depends not only on what is momentarily present, but also on what was previously attended.

  17. QUICK RELEASABLE DRIVE

    DOEpatents

    Dickson, J.J.

    1958-07-01

    A quick releasable mechanical drive system suitable for use in a nuclear reactor is described. A small reversible motor positions a control rod by means of a worm and gear speed reducer, a magnetic torque clutch, and a bell crank. As the control rod is raised to the operating position, a heavy coil spring is compressed. In the event of an emergency indicated by either a''scram'' signal or a power failure, the current to the magnetic clutch is cut off, thereby freeing the coil spring and the bell crank positioner from the motor and speed reduction gearing. The coil spring will immediately act upon the bell crank to cause the insertion of the control rod. This arrangement will allow the slow, accurate positioning of the control rod during reactor operation, while providing an independent force to rapidly insert the rod in the event of an emergency.

  18. Controlled release formulations of acephate: water and soil release kinetics.

    PubMed

    Nisar, Keyath; Kumar, Jitendra; Shakil, Najam A; Walia, Suresh; Parmar, Balraj S

    2009-08-01

    Controlled release formulations of insecticide acephate (O,S-dimethyl acetylphosphoramidothioate) have been prepared using commercially available polyvinyl chloride, carboxy methyl cellulose and carboxy methyl cellulose with kaolinite. Kinetics of acephate release in soil and water from the different formulations was studied in comparison with the commercially available formulation 75 DF. Release from the commercial formulation was faster than the new controlled pesticide release (CR) formulations. Addition of clay in the carboxy methyl cellulose matrix reduced the rate of release. The diffusion exponent (n value) of acephate in water and soil ranged from 0.462 to 0.875 and 0.420 to 0.547 respectively in the tested formulations. The release was diffusion controlled with a half release time (T(1/2)) of 2.97 to 52.41 days in water and 2.98 to 76.38 days in soil from different matrices. The maximum release of acephate in water and soil from controlled released formulations occurred between 6.33 to 36.34 and 12.49 to 29.09 days respectively. The results suggest that depending upon the polymer matrix used, the application rate of acephate can be optimized to achieve insect control at the desired level and period. PMID:20183059

  19. Optogenetic control of ATP release

    NASA Astrophysics Data System (ADS)

    Lewis, Matthew A.; Joshi, Bipin; Gu, Ling; Feranchak, Andrew; Mohanty, Samarendra K.

    2013-03-01

    Controlled release of ATP can be used for understanding extracellular purinergic signaling. While coarse mechanical forces and hypotonic stimulation have been utilized in the past to initiate ATP release from cells, these methods are neither spatially accurate nor temporally precise. Further, these methods cannot be utilized in a highly effective cell-specific manner. To mitigate the uncertainties regarding cellular-specificity and spatio-temporal release of ATP, we herein demonstrate use of optogenetics for ATP release. ATP release in response to optogenetic stimulation was monitored by Luciferin-Luciferase assay (North American firefly, photinus pyralis) using luminometer as well as mesoscopic bioluminescence imaging. Our result demonstrates repetitive release of ATP subsequent to optogenetic stimulation. It is thus feasible that purinergic signaling can be directly detected via imaging if the stimulus can be confined to single cell or in a spatially-defined group of cells. This study opens up new avenue to interrogate the mechanisms of purinergic signaling.

  20. Alteration of the interconversion of pyruvate and malate in the plastid or cytosol of ripening tomato fruit invokes diverse consequences on sugar but similar effects on cellular organic acid, metabolism, and transitory starch accumulation.

    PubMed

    Osorio, Sonia; Vallarino, José G; Szecowka, Marek; Ufaz, Shai; Tzin, Vered; Angelovici, Ruthie; Galili, Gad; Fernie, Alisdair R

    2013-02-01

    The aim of this work was to investigate the effect of decreased cytosolic phosphoenolpyruvate carboxykinase (PEPCK) and plastidic NADP-dependent malic enzyme (ME) on tomato (Solanum lycopersicum) ripening. Transgenic tomato plants with strongly reduced levels of PEPCK and plastidic NADP-ME were generated by RNA interference gene silencing under the control of a ripening-specific E8 promoter. While these genetic modifications had relatively little effect on the total fruit yield and size, they had strong effects on fruit metabolism. Both transformants were characterized by lower levels of starch at breaker stage. Analysis of the activation state of ADP-glucose pyrophosphorylase correlated with the decrease of starch in both transformants, which suggests that it is due to an altered cellular redox status. Moreover, metabolic profiling and feeding experiments involving positionally labeled glucoses of fruits lacking in plastidic NADP-ME and cytosolic PEPCK activities revealed differential changes in overall respiration rates and tricarboxylic acid (TCA) cycle flux. Inactivation of cytosolic PEPCK affected the respiration rate, which suggests that an excess of oxaloacetate is converted to aspartate and reintroduced in the TCA cycle via 2-oxoglutarate/glutamate. On the other hand, the plastidic NADP-ME antisense lines were characterized by no changes in respiration rates and TCA cycle flux, which together with increases of pyruvate kinase and phosphoenolpyruvate carboxylase activities indicate that pyruvate is supplied through these enzymes to the TCA cycle. These results are discussed in the context of current models of the importance of malate during tomato fruit ripening.

  1. l-Lactate metabolism in HEP G2 cell mitochondria due to the l-lactate dehydrogenase determines the occurrence of the lactate/pyruvate shuttle and the appearance of oxaloacetate, malate and citrate outside mitochondria.

    PubMed

    Pizzuto, Roberto; Paventi, Gianluca; Porcile, Carola; Sarnataro, Daniela; Daniele, Aurora; Passarella, Salvatore

    2012-09-01

    As part of an ongoing study of l-lactate metabolism both in normal and in cancer cells, we investigated whether and how l-lactate metabolism occurs in mitochondria of human hepatocellular carcinoma (Hep G2) cells. We found that Hep G2 cell mitochondria (Hep G2-M) possess an l-lactate dehydrogenase (ml-LDH) restricted to the inner mitochondrial compartments as shown by immunological analysis, confocal microscopy and by assaying ml-LDH activity in solubilized mitochondria. Cytosolic and mitochondrial l-LDHs were found to differ from one another in their saturation kinetics. Having shown that l-lactate itself can enter Hep G2 cells, we found that Hep G2-M swell in ammonium l-lactate, but not in ammonium pyruvate solutions, in a manner inhibited by mersalyl, this showing the occurrence of a carrier-mediated l-lactate transport in these mitochondria. Occurrence of the l-lactate/pyruvate shuttle and the appearance outside mitochondria of oxaloacetate, malate and citrate arising from l-lactate uptake and metabolism together with the low oxygen consumption and membrane potential generation are in favor of an anaplerotic role for l-LAC in Hep G2-M.

  2. Controlled Release Applications of Organometals.

    ERIC Educational Resources Information Center

    Thayer, John S.

    1981-01-01

    Reviews two classes of controlled release organometals: (1) distributional, to distribute bioactive materials to control a certain target organism; and (2) protective, to protect surface or interior of some structure from attach by organisms. Specific examples are given including a discussion of controlled release for schistosomiasis. (SK)

  3. Analysis of Peptidoglycan Fragment Release.

    PubMed

    Schaub, Ryan E; Lenz, Jonathan D; Dillard, Joseph P

    2016-01-01

    Most bacteria break down a significant portion of their cell wall peptidoglycan during each round of growth and cell division. This process generates peptidoglycan fragments of various sizes that can either be imported back into the cytoplasm for recycling or released from the cell. Released fragments have been shown to act as microbe-associated molecular patterns for the initiation of immune responses, as triggers for the initiation of mutualistic host-microbe relationships, and as signals for cell-cell communication in bacteria. Characterizing these released peptidoglycan fragments can, therefore, be considered an important step in understanding how microbes communicate with other organisms in their environments. In this chapter, we describe methods for labeling cell wall peptidoglycan, calculating the rate at which peptidoglycan is turned over, and collecting released peptidoglycan to determine the abundance and species of released fragments. Methods are described for both the separation of peptidoglycan fragments by size-exclusion chromatography and further detailed analysis by HPLC.

  4. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed.

  5. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed. PMID:26952168

  6. Kepler Data Release 4 Notes

    NASA Technical Reports Server (NTRS)

    Van Cleve, Jeffrey (Editor); Jenkins, Jon; Caldwell, Doug; Allen, Christopher L.; Batalha, Natalie; Bryson, Stephen T.; Chandrasekaran, Hema; Clarke, Bruce D.; Cote, Miles T.; Dotson, Jessie L.; Gilliland, Ron; Girouard, Forrest; Haas, Michael R.; Hall, Jennifer; Ibrahim, Khadeejah; Klaus, Todd; Kolodziejczak, Jeff; Li, Jie; McCauliff, Sean D.; Middour, Christopher K.; Pletcher, David L.; Quintana, Elisa V.; Tenenbaum, Peter G.; Twicken, Joe; Uddin, Akm Kamal

    2010-01-01

    The Data Analysis Working Group have released long and short cadence materials, including FFIs and Dropped Targets for the Public. The Kepler Science Office considers Data Release 4 to provide "browse quality" data. These notes have been prepared to give Kepler users of the Multimission Archive at STScl (MAST) a summary of how the data were collected and prepared, and how well the data processing pipeline is functioning on flight data. They will be updated for each release of data to the public archive and placed on MAST along with other Kepler documentation, at http://archive.stsci.edu/kepler/documents.html. Data release 3 is meant to give users the opportunity to examine the data for possibly interesting science and to involve the users in improving the pipeline for future data releases. To perform the latter service, users are encouraged to notice and document artifacts, either in the raw or processed data, and report them to the Science Office.

  7. Nitrogen release during coal combustion

    SciTech Connect

    Baxter, L.L.; Mitchell, R.E.; Fletcher, T.H.; Hurt, R.H.

    1995-02-01

    Experiments in entrained flow reactors at combustion temperatures are performed to resolve the rank dependence of nitrogen release on an elemental basis for a suite of 15 U.S. coals ranging from lignite to low-volatile bituminous. Data were obtained as a function of particle conversion, with overall mass loss up to 99% on a dry, ash-free basis. Nitrogen release rates are presented relative to both carbon loss and overall mass loss. During devolatilization, fractional nitrogen release from low-rank coals is much slower than fractional mass release and noticeably slower than fractional carbon release. As coal rank increases, fractional nitrogen release rate relative to that of carbon and mass increases, with fractional nitrogen release rates exceeding fractional mass and fractional carbon release rates during devolatilization for high-rank (low-volatile bituminous) coals. At the onset of combustion, nitrogen release rates increase significantly. For all coals investigated, cumulative fractional nitrogen loss rates relative to those of mass and carbon passes through a maximum during the earliest stages of oxidation. The mechanism for generating this maximum is postulated to involve nascent thermal rupture of nitrogen-containing compounds and possible preferential oxidation of nitrogen sites. During later stages of oxidation, the cumulative fractional loss of nitrogen approaches that of carbon for all coals. Changes in the relative release rates of nitrogen compared to those of both overall mass and carbon during all stages of combustion are attributed to a combination of the chemical structure of coals, temperature histories during combustion, and char chemistry.

  8. Toxics Release Inventory indicates big increases in releases

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-01-01

    Nearly 4 billion pounds of tracked toxic chemicals were released into the environment throughout the United States during 2010, according to an analysis by the U.S. Environmental Protection Agency (EPA) of the Toxics Release Inventory (TRI), the agency announced on 5 January. This is a 16% increase above 2009. The agency said the increase is mainly due to changes in the metal-mining sector, where differences in the chemical composition of ore being mined can result in significant changes in the amount of toxic chemicals. The chemical and primary metals industries were other sectors with increases in toxic releases in 2010, the latest year for which data collection is complete. EPA also noted that although releases in 2010 were higher than during the previous 2 years, they were lower than in 2007 and in prior years.

  9. Commercial SNF Accident Release Fractions

    SciTech Connect

    J. Schulz

    2004-11-05

    The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the

  10. Controlled release liquid dosage formulation

    DOEpatents

    Benton, Ben F.; Gardner, David L.

    1989-01-01

    A liquid dual coated dosage formulation sustained release pharmaceutic having substantial shelf life prior to ingestion is disclosed. A dual coating is applied over controlled release cores to form dosage forms and the coatings comprise fats melting at less than approximately 101.degree. F. overcoated with cellulose acetate phthalate or zein. The dual coated dosage forms are dispersed in a sugar based acidic liquid carrier such as high fructose corn syrup and display a shelf life of up to approximately at least 45 days while still retaining their release profiles following ingestion. Cellulose acetate phthalate coated dosage form cores can in addition be dispersed in aqueous liquids of pH <5.

  11. Estimating emissions from accidental releases

    SciTech Connect

    Wolf, D.B.

    1996-12-31

    The Clean Air Amendments (CAAA) of 1990 have an objective sources of air emissions through programs such as Title III, which is aimed at reducing hazardous air pollutant emissions. However, under Section 112(r) of the CAAA of 1990, the U.S. Environmental Protection Agency (EPA) has also developed requirements for owners and operators of facilities regulated for hazardous substances to implement accidental release prevention programs for non-continuous emissions. Provisions of 112(r) include programs for release prevention, emergency planning and risk management. This paper examines methodologies available to regulated facilities for estimating accidental release emissions and determining off-site impacts.

  12. SELF-RELEASING GRAPPLING DEVICE

    DOEpatents

    Hoover, D.A. Sr.

    1963-11-01

    >A self-releasing grappling device that lifts by virtue of engagement between clamping jaws and the undercut lower side of a conical head of a lifting lug attached to the object to be lifted and employs a releasing sleeve on the lug to free the jaws from the lug is presented. When the jaws are to be released, they are dropped over the releasing sleeve, which is located well below lug head. When the jaws are lifted, they engage a conical surface on the sleeve and lift it up to the head of the lifting lug. In this position of the sleeve, the lower side of the lug head is covered by the sleeve and so cannot be engaged by the jaws, which move past before clearing the sleeve. (AEC)

  13. Best practices for code release

    NASA Astrophysics Data System (ADS)

    Berriman, G. Bruce

    2016-01-01

    In this talk, I want to describe what I think are the best practices for releasing code and having it adopted by end users. Make sure your code is licensed, so users will know how the software can be used and modified, and place your code in a public repository that (and make sure that you follow institutional policies in doing this). Yet licensing and releasing code are not enough: the code must be organized and documented so users can understand what it does, what its limitations are, and how to build and use it. I will describe what I think are best practices in developing the content to support release, including tutorials, design documents, specifications of interfaces and so on. Much of what I have learned on based on ten years of experience in supporting releases of the Montage Image Mosaic Engine.

  14. Tyrosine - Effects on catecholamine release

    NASA Technical Reports Server (NTRS)

    Acworth, Ian N.; During, Matthew J.; Wurtman, Richard J.

    1988-01-01

    Tyrosine administration elevates striatal levels of dopamine metabolites in animals given treatments that accelerate nigrostriatal firing, but not in untreated rats. We examined the possibility that the amino acid might actually enhance dopamine release in untreated animals, but that the technique of measuring striatal dopamine metabolism was too insensitive to demonstrate such an effect. Dopamine release was assessed directly, using brain microdialysis of striatal extracellular fluid. Tyrosine administration (50-200 mg/kg IP) did indeed cause a dose related increase in extracellular fluid dopamine levels with minor elevations in levels of DOPAC and HVA, its major metabolites, which were not dose-related. The rise in dopamine was short-lived, suggesting that receptor-mediated feedback mechanisms responded to the increased dopamine release by diminishing neuronal firing or sensitivity to tyrosine. These observations indicate that measurement of changes in striatal DOPAC and HVA, if negative, need not rule out increases in nigrostriatal dopamine release.

  15. Energy release in solar flares

    NASA Technical Reports Server (NTRS)

    Brown, John C.; Correia, Emilia; Farnik, Frantisek; Garcia, Howard; Henoux, Jean-Claude; La Rosa, Ted N.; Machado, Marcos E. (Compiler); Nakajima, Hiroshi; Priest, Eric R.

    1994-01-01

    Team 2 of the Ottawa Flares 22 Workshop dealt with observational and theoretical aspects of the characteristics and processes of energy release in flares. Main results summarized in this article stress the global character of the flaring phenomenon in active regions, the importance of discontinuities in magnetic connectivity, the role of field-aligned currents in free energy storage, and the fragmentation of energy release in time and space.

  16. 19 CFR 142.41 - Line Release.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Line Release. 142.41 Section 142.41 Customs Duties... (CONTINUED) ENTRY PROCESS Line Release § 142.41 Line Release. Line Release is an automated system designed to... importers of merchandise which CBP deems to be repetitive and high volume. Line Release may be used only...

  17. 19 CFR 142.41 - Line Release.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Line Release. 142.41 Section 142.41 Customs Duties... (CONTINUED) ENTRY PROCESS Line Release § 142.41 Line Release. Line Release is an automated system designed to... importers of merchandise which Customs deems to be repetitive and high volume. Line Release may be used...

  18. Isolated durum wheat and potato cell mitochondria oxidize externally added NADH mostly via the malate/oxaloacetate shuttle with a rate that depends on the carrier-mediated transport.

    PubMed

    Pastore, Donato; Di Pede, Sergio; Passarella, Salvatore

    2003-12-01

    We investigated whether and how mitochondria from durum wheat (Triticum durum Desf.) and potato (Solanum tuberosum), isolated from etiolated shoots and a cell suspension culture, respectively, oxidize externally added NADH via the mitochondrial shuttles; in particular, we compared the shuttles and the external NADH dehydrogenase (NADH DHExt) with respect to their capacity to oxidize external NADH. We found that external NADH and NADPH can be oxidized via two separate DHExt, whereas under conditions in which the activities of NAD(P)H DHExt are largely prevented, NADH (but not NADPH) is oxidized in the presence of external malate (MAL) and MAL dehydrogenase, in a manner sensitive to several non-penetrant compounds according to the occurrence of the MAL/oxaloacetate (OAA) shuttle. In durum wheat mitochondria and potato cell mitochondria, the rate of NADH oxidation was limited by the rate of a novel carrier, the MAL/OAA antiporter, which is different from other carriers thought to transport OAA across the mitochondrial membrane. No NAD(P)H oxidation occurred arising from the MAL/Aspartate and the alpha-glycerophosphate/dihydroxyacetonphosphate shuttles. We determined the kinetic parameters of the enzymes and the antiporter involved in NADH oxidation, and, on the basis of a kinetic analysis, we showed that, at low physiological NADH concentrations, oxidation via the MAL/OAA shuttle occurred with a higher efficiency than that due to the NADH DHExt (about 100- and 10-fold at 1 microm NADH in durum wheat mitochondria and in potato cell mitochondria, respectively). The NADH DHExt contribution to NADH oxidation increased with increasing NADH concentration.

  19. Optimization of release from magnetically controlled polymeric drug release devices.

    PubMed

    Edelman, E R; Langer, R

    1993-07-01

    Release rates from drug:polymer matrices embedded with small magnets increase in the presence of oscillating magnetic fields. Previous studies of these systems have defined those parameters that determine the extent of the increase in release, and implied that not only was the force generated within the matrix an important determinant of the extent of modulation but also that the greater the amount of matrix actually displaced, the greater the observed modulation. We investigated this possibility in the magnetic system and developed a model taking into account the intersection of the volume of a cylindrical polymer-drug magnet embedded matrix with an imaginary sphere representing the upper limit of matrix deformation by the magnet. The intersection correlated in a linear fashion with the increase in release (slope = 1.16 +/- 0.26, R = 0.864, P = 0.003, s.e.e. = 1.38). Magnet orientation alone was insufficient to explain the data. It appears that a modulated system is optimized when the modulating force overlaps precisely with the maximum amount of matrix drug that can be released. If the size of the matrix, position of the magnet, force generated on the matrix by the magnet, viscoelastic properties of the matrix, etc. are not matched then modulation is inefficient. These results should provide further insight into and a means of optimization for externally regulated controlled release systems.

  20. Added release time in diffusion/dissolution coupled release.

    PubMed

    Nuxoll, Eric

    2015-10-15

    While increasingly sophisticated models have been developed to more accurately predict dispersed solute release from complex systems, distillation of their results into quantitative trends has been difficult. Here, the numerically calculated release profiles of coupled diffusion/dissolution systems are quantified by their cumulative release time (CRT) and compared against corresponding diffusion-controlled limits. The increase in CRT due to a finite dissolution rate was found to vary inversely with the second Damköhler number across several orders of magnitude, and also vary linearly with the amount of solid drug loaded in the system. The analytical nature of the relationship provides new physical insights into the system and appears to be indifferent to the form of the secondary rate-limiting step. This work provides a simple analytical expression with which one can not only predict the mean release time for a given set of parameter values, but understand precisely how each parameter value will affect it. The simplicity of the correlation and the lack of apparent limits to its validity also suggest the existence of an analytical pathway for its derivation, which may yield additional insights into the effect of secondary rate processes on controlled release. PMID:26276252

  1. Added release time in diffusion/dissolution coupled release.

    PubMed

    Nuxoll, Eric

    2015-10-15

    While increasingly sophisticated models have been developed to more accurately predict dispersed solute release from complex systems, distillation of their results into quantitative trends has been difficult. Here, the numerically calculated release profiles of coupled diffusion/dissolution systems are quantified by their cumulative release time (CRT) and compared against corresponding diffusion-controlled limits. The increase in CRT due to a finite dissolution rate was found to vary inversely with the second Damköhler number across several orders of magnitude, and also vary linearly with the amount of solid drug loaded in the system. The analytical nature of the relationship provides new physical insights into the system and appears to be indifferent to the form of the secondary rate-limiting step. This work provides a simple analytical expression with which one can not only predict the mean release time for a given set of parameter values, but understand precisely how each parameter value will affect it. The simplicity of the correlation and the lack of apparent limits to its validity also suggest the existence of an analytical pathway for its derivation, which may yield additional insights into the effect of secondary rate processes on controlled release.

  2. Identification of the mcpA and mcpM genes, encoding methyl-accepting proteins involved in amino acid and l-malate chemotaxis, and involvement of McpM-mediated chemotaxis in plant infection by Ralstonia pseudosolanacearum (formerly Ralstonia solanacearum phylotypes I and III).

    PubMed

    Hida, Akiko; Oku, Shota; Kawasaki, Takeru; Nakashimada, Yutaka; Tajima, Takahisa; Kato, Junichi

    2015-11-01

    Sequence analysis has revealed the presence of 22 putative methyl-accepting chemotaxis protein (mcp) genes in the Ralstonia pseudosolanacearum GMI1000 genome. PCR analysis and DNA sequencing showed that the highly motile R. pseudosolanacearum strain Ps29 possesses homologs of all 22 R. pseudosolanacearum GMI1000 mcp genes. We constructed a complete collection of single mcp gene deletion mutants of R. pseudosolanacearum Ps29 by unmarked gene deletion. Screening of the mutant collection revealed that R. pseudosolanacearum Ps29 mutants of RSp0507 and RSc0606 homologs were defective in chemotaxis to l-malate and amino acids, respectively. RSp0507 and RSc0606 homologs were designated mcpM and mcpA. While wild-type R. pseudosolanacearum strain Ps29 displayed attraction to 16 amino acids, the mcpA mutant showed no response to 12 of these amino acids and decreased responses to 4 amino acids. We constructed mcpA and mcpM deletion mutants of highly virulent R. pseudosolanacearum strain MAFF106611 to investigate the contribution of chemotaxis to l-malate and amino acids to tomato plant infection. Neither single mutant exhibited altered virulence for tomato plants when tested by root dip inoculation assays. In contrast, the mcpM mutant (but not the mcpA mutant) was significantly less infectious than the wild type when tested by a sand soak inoculation assay, which requires bacteria to locate and invade host roots from sand. Thus, McpM-mediated chemotaxis, possibly reflecting chemotaxis to l-malate, facilitates R. pseudosolanacearum motility to tomato roots in sand.

  3. 26 CFR 301.6343-1 - Requirement to release levy and notice of release.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... conditions in paragraph (b) of this section (conditions requiring release) exist. The director must make a determination whether any of the conditions requiring release exist if a taxpayer submits a request for release... release exists. (b) Conditions requiring release. The director must release the levy upon all or a part...

  4. Sand release apparatus and method

    SciTech Connect

    Hall, L.D.

    1991-05-28

    This patent describes a sand release apparatus for enabling the release of a pump. It comprises first and second telescoped tubular sleeves; a first restricting means; sleeve located drain opening means and means for enabling controlled separation of the pump from the apparatus at a specified joint. This patent also describes a method for releasing a pump determined to be sand locked. It comprises applying an upward force on the sucker rod string to break a shear pin restricting relative axial extension of telescoped sleeve members connected in the well below the pump; extending the telescoped sleeve members to expose drain openings to permit sand to flow away from the annular space; and disconnecting from the tubing string below the pump to pull the pump free of the sand locked condition.

  5. Controlled release from recombinant polymers.

    PubMed

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-09-28

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.

  6. Controlled Release from Recombinant Polymers

    PubMed Central

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-01-01

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed. PMID:24956486

  7. Payload holddown and release mechanism

    NASA Technical Reports Server (NTRS)

    Chaput, Dale; Visconti, Mark; Edwards, Michael; Moran, Tom

    1994-01-01

    A payload holddown and release mechanism, designated the Model 1172, was designed and built at G&H Technology during the winter of 1992/1993. The mechanism is able to restrain and release a 45-pound payload with minimal tipoff. The payload is held in place by a stainless steel band and released using electrically triggered non-explosive actuators. These actuators provide reliable operation with negligible shock and no special handling requirements. The performance of the mechanism was demonstrated in two flight tests. Data showed pitch and yaw tipoff rates of less than 0.07 radian (4 degree) per second. The Model 1172 design is an efficient replacement for conventional payload deployment devices, especially where low transmitted shock is required.

  8. Nanostructured Diclofenac Sodium Releasing Material

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Harlin, A.; Seppälä, J.; Ashammakhi, N.

    2008-02-01

    Various techniques have been developed to produce second generation biomaterials for tissue repair. These include extrusion, molding, salt leaching, spinning etc, but success in regenerating tissues has been limited. It is important to develop porous material, yet with a fibrous structure for it to be biomimetic. To mimic biological tissues, the extra-cellular matrix usually contains fibers in nano scale. To produce nanostructures, self-assembly or electrospinning can be used. Adding a drug release function to such a material may advance applications further for use in controlled tissue repair. This turns the resulting device into a multifunctional porous, fibrous structure to support cells and drug releasing properties in order to control tissue reactions. A bioabsorbable poly(ɛ-caprolactone-co-D,L lactide) 95/5 (PCL) was made into diluted solution using a solvent, to which was added 2w-% of diclofenac sodium (DS). Nano-fibers were made by electrospinning onto substrate. Microstructure of the resulting nanomat was studied using SEM and drug release profiles with UV/VIS spectroscopy. Thickness of the electrospun nanomat was about 2 mm. SEM analysis showed that polymeric nano-fibers containing drug particles form a highly interconnected porous nano structure. Average diameter of the nano-fibers was 130 nm. There was a high burst peak in drug release, which decreased to low levels after one day. The used polymer has slow a degradation rate and though the nanomat was highly porous with a large surface area, drug release rate is slow. It is feasible to develop a nano-fibrous porous structure of bioabsorbable polymer, which is loaded with test drug. Drug release is targeted at improving the properties of biomaterial for use in controlled tissue repair and regeneration.

  9. Hydrocarbon release investigations in Missouri

    SciTech Connect

    Fels, J.B.

    1996-09-01

    Hydrocarbon releases are among the most common environmental problems in Missouri, as well as across the country. Old, unprotected underground storage tanks and buried piping from the tanks to pumps are notorious sources of petroleum contamination at LUST (leaking underground storage tank) sites. Missouri has an estimated 5000 LUST sites across the state with the majority being simple spills into clay-rich soils or into a shallow perched water system. However, in the southern half of the state, where residual soils and karst bedrock are not conducive to trapping such releases, significant groundwater supplies are at risk. This article discusses the process used to identify the source of contamination.

  10. Bioinspired, releasable quorum sensing modulators.

    PubMed

    Gomes, José; Grunau, Alexander; Lawrence, Adrien K; Eberl, Leo; Gademann, Karl

    2013-01-01

    We demonstrate the synthesis and immobilization of natural product hybrids featuring an acyl-homoserine lactone and a nitrodopamine onto biocompatible TiO(2) surfaces through an operationally simple dip-and-rinse procedure. The resulting immobilized hybrids were shown to be powerful quorum sensing (QS) activators in Pseudomonas strains acting by slow release from the surface. PMID:23169441

  11. 2014 Pee Dee germplasm releases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PD 05035, PD 05041, PD 05064, PD 05069, PD 05070, PD 05071, PD 06001, and PD 06078 are noncommercial breeding lines of cotton jointly released by the Agricultural Research Service, United States Department of Agriculture, Clemson University Experiment Station, and Cotton Incorporated in 2014. These ...

  12. Photodegradable Polyesters for Triggered Release

    PubMed Central

    Lv, Cong; Wang, Zhen; Wang, Peng; Tang, Xinjing

    2012-01-01

    Photodegradable polyesters were synthesized with a photolabile monomer 2-nitrophenylethylene glycol and dioyl chlorides with different lengths. These polymers can be assembled to form polymeric particles with encapsulation of target substances. Light activation can degrade these particles and release payloads in both aqueous solutions and RAW 264.7 cells. PMID:23208376

  13. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  14. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  15. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  16. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  17. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  18. Index to NASA News Releases 1995

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This issue of the index to NASA News Releases contains a listing of news releases distributed by the Office of Public Affairs, NASA Headquarters, during 1995. The index is arranged in six sections: Subject index, Personal name index, News release number index, Accession number index, Speeches, and News releases.

  19. Kepler Data Release 3 Notes

    NASA Technical Reports Server (NTRS)

    Cleve, Jeffrey E.

    2010-01-01

    This describes the collection of data and the processing done on it so when researchers around the world get the Kepler data sets (which are a set of pixels from the telescope of a particular target (star, galaxy or whatever) over a 3 month period) they can adjust their algorithms fro things that were done (like subtracting all of one particular wavelength for example). This is used to calibrate their own algorithms so that they know what it is they are starting with. It is posted so that whoever is accessing the publicly available data (not all of it is made public) can understand it .. (most of the Kepler data is under restriction for 1 - 4 years and is not available, but the handbook is for everyone (public and restricted) The Data Analysis Working Group have released long and short cadence materials, including FFls and Dropped Targets for the Public. The Kepler Science Office considers Data Release 3 to provide "browse quality" data. These notes have been prepared to give Kepler users of the Multimission Archive at STScl (MAST) a summary of how the data were collected and prepared, and how well the data processing pipeline is functioning on flight data. They will be updated for each release of data to the public archive and placed on MAST along with other Kepler documentation, at http:// archive.stsci.edu/kepler/documents.html .Data release 3 is meant to give users the opportunity to examine the data for possibly interesting science and to involve the users in improving the pipeline for future data releases. To perform the latter service, users are encouraged to notice and document artifacts, either in the raw or processed data, and report them to the Science Office.

  20. α-Hydroxy coordination of mononuclear vanadyl citrate, malate and S-citramalate with N-heterocycle ligand, implying a new protonation pathway of iron-vanadium cofactor in nitrogenase.

    PubMed

    Chen, Can-Yu; Chen, Mao-Long; Chen, Hong-Bin; Wang, Hongxin; Cramer, Stephen P; Zhou, Zhao-Hui

    2014-12-01

    Unlike the most of α-alkoxy coordination in α-hydroxycarboxylates to vanadium, novel α-hydroxy coordination to vanadium(IV) has been observed for a series of chiral and achiral monomeric α-hydroxycarboxylato vanadyl complexes [VO(H2cit)(bpy)]·2H2O (1), [VO(Hmal)(bpy)]·H2O (2), [VO(H2cit)(phen)]·1.5H2O (3), [VO(Hmal)(phen)]·H2O (4), and [(Δ)VO(S-Hcitmal)(bpy)]·2H2O (5), [VO(H2cit)(phen)]2·6.5H2O (6), which were isolated from the reactions of vanadyl sulfate with α-hydroxycarboxylates and N-heterocycle ligands in acidic solution. The complexes feature a tridentate citrate, malate or citramalate that chelates to vanadium atom through their α-hydroxy, α-carboxy and β-carboxy groups; while the other β-carboxylic acidic group of citrate is free to participate strong hydrogen bonds with lattice water molecule. The neutral α-hydroxy group also forms strong intermolecular hydrogen bonds with water molecule and the negatively-charged α-carboxy group in the environment. The inclusion of a hydrogen ion in α-alkoxy group results in the formation of a series of neutral complexes with one less positive charge. There are two different configurations of citrate with respect to the trans-position of axial oxo group, where the complex with trans-hydroxy configuration seems more stable with less hindrance. The average bond distances of V-Ohydroxy and V-Oα-carboxy are 2.196 and 2.003Å respectively, which are comparable to the VO distance (2.15Å) of homocitrate in FeV-cofactor of V-nitrogenase. A new structural model is suggested for R-homocitrato iron vanadium cofactor as VFe7S9C(R-Hhomocit) (H4homocit=homocitric acid) with one more proton in homocitrate ligand.

  1. α-Hydroxy coordination of mononuclear vanadyl citrate, malate and S-citramalate with N-heterocycle ligand, implying a new protonation pathway of iron-vanadium cofactor in nitrogenase.

    PubMed

    Chen, Can-Yu; Chen, Mao-Long; Chen, Hong-Bin; Wang, Hongxin; Cramer, Stephen P; Zhou, Zhao-Hui

    2014-12-01

    Unlike the most of α-alkoxy coordination in α-hydroxycarboxylates to vanadium, novel α-hydroxy coordination to vanadium(IV) has been observed for a series of chiral and achiral monomeric α-hydroxycarboxylato vanadyl complexes [VO(H2cit)(bpy)]·2H2O (1), [VO(Hmal)(bpy)]·H2O (2), [VO(H2cit)(phen)]·1.5H2O (3), [VO(Hmal)(phen)]·H2O (4), and [(Δ)VO(S-Hcitmal)(bpy)]·2H2O (5), [VO(H2cit)(phen)]2·6.5H2O (6), which were isolated from the reactions of vanadyl sulfate with α-hydroxycarboxylates and N-heterocycle ligands in acidic solution. The complexes feature a tridentate citrate, malate or citramalate that chelates to vanadium atom through their α-hydroxy, α-carboxy and β-carboxy groups; while the other β-carboxylic acidic group of citrate is free to participate strong hydrogen bonds with lattice water molecule. The neutral α-hydroxy group also forms strong intermolecular hydrogen bonds with water molecule and the negatively-charged α-carboxy group in the environment. The inclusion of a hydrogen ion in α-alkoxy group results in the formation of a series of neutral complexes with one less positive charge. There are two different configurations of citrate with respect to the trans-position of axial oxo group, where the complex with trans-hydroxy configuration seems more stable with less hindrance. The average bond distances of V-Ohydroxy and V-Oα-carboxy are 2.196 and 2.003Å respectively, which are comparable to the VO distance (2.15Å) of homocitrate in FeV-cofactor of V-nitrogenase. A new structural model is suggested for R-homocitrato iron vanadium cofactor as VFe7S9C(R-Hhomocit) (H4homocit=homocitric acid) with one more proton in homocitrate ligand. PMID:25240212

  2. Neutron-absorber release device

    DOEpatents

    VAN Erp, Jan B.; Kimont, Edward L.

    1976-01-01

    A resettable device is provided for supporting an object, sensing when an environment reaches a critical temperature and releasing the object when the critical temperature is reached. It includes a flexible container having a material inside with a melting point at the critical temperature. The object's weight is supported by the solid material which gives rigidity to the container until the critical temperature is reached at which point the material in the container melts. The flexible container with the now fluid material inside has insufficient strength to support the object which is thereby released. Biasing means forces the container back to its original shape so that when the temperature falls below the melting temperature the material again solidifies, and the object may again be supported by the device.

  3. Neural control of renin release.

    PubMed

    Stella, A; Golin, R; Zanchetti, A

    1989-02-01

    Among the major mechanisms controlling the renal release of renin, renal nerves are known to exert a direct stimulating action on juxtaglomerular cells that is mediated by beta-adrenoceptors. Activation of the renal nerves also exerts an important permissive role in order to amplify and possibly accelerate responses to stimuli affecting the vascular and macula densa mechanisms. Reduction of renal perfusion pressure, intravenous infusion of furosemide, and captopril administration cause a greater increase in renin release from innervated kidneys than from denervated kidneys. A complex interaction between neural and non-neural mechanisms in the control of renin secretion is suggested. Efferent renal nerve activity controlling the renin secretion rate is mainly under the inhibitory influence of vagal afferent fibers originating from the cardiopulmonary region. Recent experiments have demonstrated that a similar reflex tonic inhibition of renin secretion is also exerted by renal afferent fibers.

  4. 14 CFR 125.373 - Original flight release or amendment of flight release.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Original flight release or amendment of flight release. 125.373 Section 125.373 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... Flight Release Rules § 125.373 Original flight release or amendment of flight release. (a) A...

  5. Nucleotide release by airway epithelia.

    PubMed

    Lazarowski, Eduardo R; Sesma, Juliana I; Seminario, Lucia; Esther, Charles R; Kreda, Silvia M

    2011-01-01

    The purinergic events regulating the airways' innate defenses are initiated by the release of purines from the epithelium, which occurs constitutively and is enhanced by chemical or mechanical stimulation. While the external triggers have been reviewed exhaustively, this chapter focuses on current knowledge of the receptors and signaling cascades mediating nucleotide release. The list of secreted purines now includes ATP, ADP, AMP and nucleotide sugars, and involves at least three distinct mechanisms reflecting the complexity of airway epithelia. First, the constitutive mechanism involves ATP translocation to the ER/Golgi complex as energy source for protein folding, and fusion of Golgi-derived vesicles with the plasma membrane. Second, goblet cells package ATP with mucins into granules, which are discharged in response to P2Y(2)R activation and Ca(2+)-dependent signaling pathways. Finally, non-mucous cells support a regulated mechanism of ATP release involving protease activated receptor (PAR)-elicited G(12/13) activation, leading to the RhoGEF-mediated exchange of GDP for GTP on RhoA, and cytoskeleton rearrangement. Together, these pathways provide fine tuning of epithelial responses regulated by purinergic signaling events. PMID:21560042

  6. Nanoparticle release from dental composites.

    PubMed

    Van Landuyt, K L; Hellack, B; Van Meerbeek, B; Peumans, M; Hoet, P; Wiemann, M; Kuhlbusch, T A J; Asbach, C

    2014-01-01

    Dental composites typically contain high amounts (up to 60 vol.%) of nanosized filler particles. There is a current concern that dental personnel (and patients) may inhale nanosized dust particles (<100 nm) during abrasive procedures to shape, finish or remove restorations but, so far, whether airborne nanoparticles are released has never been investigated. In this study, composite dust was analyzed in real work conditions. Exposure measurements of dust in a dental clinic revealed high peak concentrations of nanoparticles in the breathing zone of both dentist and patient, especially during aesthetic treatments or treatments of worn teeth with composite build-ups. Further laboratory assessment confirmed that all tested composites released very high concentrations of airborne particles in the nanorange (>10(6)cm(-3)). The median diameter of airborne composite dust varied between 38 and 70 nm. Electron microscopic and energy dispersive X-ray analysis confirmed that the airborne particles originated from the composite, and revealed that the dust particles consisted of filler particles or resin or both. Though composite dust exhibited no significant oxidative reactivity, more toxicological research is needed. To conclude, on manipulation with the bur, dental composites release high concentrations of nanoparticles that may enter deeply into the lungs.

  7. Ultrasound-Assisted Endoscopic Carpal Tunnel Release.

    PubMed

    Ohuchi, Hiroshi; Hattori, Soichi; Shinga, Kotaro; Ichikawa, Ken; Yamada, Shin

    2016-06-01

    Various surgical procedures for carpal tunnel syndrome exist, such as open release, ultrasound-guided percutaneous release, and endoscopic release. Postoperative pain, scarring, and slow recovery to normal function are reported complications of open release. Damage to vessels and the median nerve and its branches underlying the transverse carpal ligament is a reported complication of ultrasound-guided percutaneous release. Damage to the superficial palmar arch and incomplete release are reported complications of endoscopic release. By performing endoscopic carpal tunnel release with ultrasound assistance, we could visualize neurovascular structures directly with the endoscope and also indirectly with ultrasound to minimize complications. We could also evaluate the morphologic changes of the median nerve dynamically before and after the release. We discuss the technique for this procedure and outline pearls and pitfalls for success. PMID:27656366

  8. Prion protein facilitates synaptic vesicle release by enhancing release probability.

    PubMed

    Robinson, Susan W; Nugent, Marie L; Dinsdale, David; Steinert, Joern R

    2014-09-01

    The cellular prion protein (PrP(C)) has been implicated in several neurodegenerative diseases as a result of protein misfolding. In humans, prion disease occurs typically with a sporadic origin where uncharacterized mechanisms induce spontaneous PrP(C) misfolding leading to neurotoxic PrP-scrapie formation (PrP(SC)). The consequences of misfolded PrP(C) signalling are well characterized but little is known about the physiological roles of PrP(C) and its involvement in disease. Here we investigated wild-type PrP(C) signalling in synaptic function as well as the effects of a disease-relevant mutation within PrP(C) (proline-to-leucine mutation at codon 101). Expression of wild-type PrP(C) at the Drosophila neuromuscular junction leads to enhanced synaptic responses as detected in larger miniature synaptic currents which are caused by enlarged presynaptic vesicles. The expression of the mutated PrP(C) leads to reduction of both parameters compared with wild-type PrP(C). Wild-type PrP(C) enhances synaptic release probability and quantal content but reduces the size of the ready-releasable vesicle pool. Partially, these changes are not detectable following expression of the mutant PrP(C). A behavioural test revealed that expression of either protein caused an increase in locomotor activities consistent with enhanced synaptic release and stronger muscle contractions. Both proteins were sensitive to proteinase digestion. These data uncover new functions of wild-type PrP(C) at the synapse with a disease-relevant mutation in PrP(C) leading to diminished functional phenotypes. Thus, our data present essential new information possibly related to prion pathogenesis in which a functional synaptic role of PrP(C) is compromised due to its advanced conversion into PrP(SC) thereby creating a lack-of-function scenario.

  9. Synapsins differentially control dopamine and serotonin release.

    PubMed

    Kile, Brian M; Guillot, Thomas S; Venton, B Jill; Wetsel, William C; Augustine, George J; Wightman, R Mark

    2010-07-21

    Synapsins are a family of synaptic vesicle proteins that are important for neurotransmitter release. Here we have used triple knock-out (TKO) mice lacking all three synapsin genes to determine the roles of synapsins in the release of two monoamine neurotransmitters, dopamine and serotonin. Serotonin release evoked by electrical stimulation was identical in substantia nigra pars reticulata slices prepared from TKO and wild-type mice. In contrast, release of dopamine in response to electrical stimulation was approximately doubled in striatum of TKO mice, both in vivo and in striatal slices, in comparison to wild-type controls. This was due to loss of synapsin III, because deletion of synapsin III alone was sufficient to increase dopamine release. Deletion of synapsins also increased the sensitivity of dopamine release to extracellular calcium ions. Although cocaine did not affect the release of serotonin from nigral tissue, this drug did enhance dopamine release. Cocaine-induced facilitation of dopamine release was a function of external calcium, an effect that was reduced in TKO mice. We conclude that synapsins play different roles in the control of release of dopamine and serotonin, with release of dopamine being negatively regulated by synapsins, specifically synapsin III, while serotonin release appears to be relatively independent of synapsins. These results provide further support for the concept that synapsin function in presynaptic terminals varies according to the neurotransmitter being released. PMID:20660258

  10. Gastrin-releasing peptide stimulates glycoconjugate release from feline trachea

    SciTech Connect

    Lundgren, J.D.; Baraniuk, J.N.; Ostrowski, N.L.; Kaliner, M.A.; Shelhamer, J.H. )

    1990-02-01

    The effect of gastrin-releasing peptide (GRP) on respiratory glycoconjugate (RGC) secretion was investigated in a feline tracheal organ culture model. RGC secretion was stimulated by GRP in a dose-dependent fashion at concentrations from 10(-8) to 10(-5) M (range 15-38% increase above control) with a peak effect within 0.5-1 h of incubation. GRP-(14-27), the receptor binding portion of GRP, and the related molecule, bombesin, also stimulated RGC secretion by approximately 20% above control. Acetyl-GRP-(20-27) stimulated RGC release by 10%, whereas GRP-(1-16) was inactive. Autoradiographic studies with 125I-GRP revealed that specific binding was restricted to the submucosal glands and the surface epithelium. A specific radioimmunoassay showed the content of GRP in feline trachea after extraction with ethanol-acetic acid to be 156 +/- 91 fmol/g wet wt. Indirect immunohistochemistry indicated that ganglion cells located just outside the cartilage contained GRP-immunoreactive materials. GRP is a novel mucus secretagogue that may participate in regulating airway mucosal gland secretion.

  11. 46 CFR 108.457 - Pressure release.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.457 Pressure release... have a means for releasing pressure that accumulates within the space if CO2 is discharged into...

  12. 46 CFR 108.457 - Pressure release.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.457 Pressure release... have a means for releasing pressure that accumulates within the space if CO2 is discharged into...

  13. 46 CFR 108.457 - Pressure release.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.457 Pressure release... have a means for releasing pressure that accumulates within the space if CO2 is discharged into...

  14. 46 CFR 108.457 - Pressure release.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.457 Pressure release... have a means for releasing pressure that accumulates within the space if CO2 is discharged into...

  15. 46 CFR 108.457 - Pressure release.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.457 Pressure release... have a means for releasing pressure that accumulates within the space if CO2 is discharged into...

  16. 28 CFR 2.33 - Release plans.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS... of parole is conditioned upon the approval of release plans by the Regional Commissioner. In general... reasonable plan for payment shall, where feasible, be included in the parole release plan....

  17. 28 CFR 2.33 - Release plans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 1 2011-07-01 2011-07-01 false Release plans. 2.33 Section 2.33 Judicial..., AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.33 Release plans. (a) A grant of parole is conditioned upon the approval of release plans by the Regional Commissioner. In...

  18. 28 CFR 2.33 - Release plans.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 1 2012-07-01 2012-07-01 false Release plans. 2.33 Section 2.33 Judicial..., AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.33 Release plans. (a) A grant of parole is conditioned upon the approval of release plans by the Regional Commissioner. In...

  19. 40 CFR 302.8 - Continuous releases.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CFR part 355, which require initial telephone and written notifications of continuous releases to be... schools, hospitals, retirement communities, or wetlands). (iv) For each hazardous substance release...) The environmental medium(a) affected by the release: (1) If surface water, the name of the...

  20. CHANGING RELEASE CRITERIA FROM PAST TO PRESENT

    SciTech Connect

    Graf, A.; Valencia, L.

    2003-02-27

    Beginning with the decommissioning of nuclear power plants the release, criteria for radioactive materials has gained importance significantly. After decommissioning and dismantling, most of the residues need not be treated as radioactive waste, since they contain only small amounts of radioactivity. The Karlsruhe Research Center already dismantled two research reactors completely (the Karlstein Super Heated Steam Reactor and the Niederaichbach Nuclear Power Plant), while several additional decommissioning projects are currently in progress. About 70 % of the total waste mass within each project can be released from the area of atomic regulations and licenses. At the Niederaichbach and Karlstein sites the release procedures and the release criteria were determined in the decommissioning license, where issues such as controlling and release values were fixed. Additionally, each step of the release process has to be coordinated with the regulator. Today the general release criteria are contained in the atomic act. Depending on the nature of the material to be released (e.g. building structures or metallic waste), and depending on the further use of the material, such as unrestricted reuse or waste disposal, release values for each nuclide are established. To prepare the release of materials, a release plan including the release measurement results is sent to the regulator, who has to officially approve the concept.

  1. 40 CFR 302.8 - Continuous releases.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CFR part 355, which require initial telephone and written notifications of continuous releases to be... release data, engineering estimates, knowledge of operating procedures, or best professional judgment to... requirements of this section, the person in charge may rely on recent release data, engineering estimates,...

  2. Individualized optimal release angles in discus throwing.

    PubMed

    Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

    2010-02-10

    The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques.

  3. 28 CFR 2.33 - Release plans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Release plans. 2.33 Section 2.33 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.33 Release plans. (a) A...

  4. Fully redundant mechanical release actuator

    NASA Technical Reports Server (NTRS)

    Lucy, Melvin H. (Inventor)

    1987-01-01

    A system is described for performing a mechanical release function exhibiting low shock. This system includes two pyrotechnic detents fixed mounted in opposing axial alignment within a cylindrical housing having two mechanical bellows. Two mechanical bellow assemblies, each having one end hermetically bonded to the housing and the other to the respective actuator pin extending from either end of the housing, ensure that all outgassing and contamination from the operation of the pyrotechnic devices will be contained within the housing and bellows. The pin on one end of the assembly is fixed mounted and supported, via a bolt or ball-and-socket joint so that when the charge corresponding to that pin ignites, the entire assembly will exhibit rectilinear movement, including the opposing pin providing the unlatching motion. The release detent pin is supported by a linear bearing and when its corresponding pyrotechnic charge ignites the pin is retracted within the housing producing the same unlatching motion without movement of the entire assembly, thus providing complete mechanical, electrical and pyrotechnic redundancy for the unlatching pin.

  5. ATP release through pannexon channels.

    PubMed

    Dahl, Gerhard

    2015-07-01

    Extracellular adenosine triphosphate (ATP) serves as a signal for diverse physiological functions, including spread of calcium waves between astrocytes, control of vascular oxygen supply and control of ciliary beat in the airways. ATP can be released from cells by various mechanisms. This review focuses on channel-mediated ATP release and its main enabler, Pannexin1 (Panx1). Six subunits of Panx1 form a plasma membrane channel termed 'pannexon'. Depending on the mode of stimulation, the pannexon has large conductance (500 pS) and unselective permeability to molecules less than 1.5 kD or is a small (50 pS), chloride-selective channel. Most physiological and pathological stimuli induce the large channel conformation, whereas the small conformation so far has only been observed with exclusive voltage activation of the channel. The interaction between pannexons and ATP is intimate. The pannexon is not only the conduit for ATP, permitting ATP efflux from cells down its concentration gradient, but the pannexon is also modulated by ATP. The channel can be activated by ATP through both ionotropic P2X as well as metabotropic P2Y purinergic receptors. In the absence of a control mechanism, this positive feedback loop would lead to cell death owing to the linkage of purinergic receptors with apoptotic processes. A control mechanism preventing excessive activation of the purinergic receptors is provided by ATP binding (with low affinity) to the Panx1 protein and gating the channel shut. PMID:26009770

  6. Diffusion rates for elevated releases

    SciTech Connect

    Ramsdell, J.V.

    1983-11-01

    A search of the literature related to diffusion from elevated sources has determined that an adequate data base exists for use in developing parameterizations for estimating diffusion rates for material released from free standing stacks at nuclear power plants. A review of published data analyses indicates that a new parameterization of horizontal diffusion rates specifically for elevated releases is not likely to significantly change the magnitudes of horizontal diffusion coefficients on the average. However, the uncertainties associated with horizontal diffusion coefficient estimates under any given set of atmospheric conditions could be reduced by a new parameterization. Similarly, a new parameterization of vertical diffusion rates would be unlikely to significantly alter the magnitudes of diffusion coefficients for unstable atmospheric conditons. However, for neutral and stable atmospheric conditions, a new parameterization of vertical diffusion rates might increase vertical diffusion coefficients significantly. The increase would move ground-level time-integrated concentration maxima closer to the plant and would increase the maxima. 55 references, 2 figures, 4 tables.

  7. Nuclear energy release from fragmentation

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Souza, S. R.; Tsang, M. B.; Zhang, Feng-Shou

    2016-08-01

    It is well known that binary fission occurs with positive energy gain. In this article we examine the energetics of splitting uranium and thorium isotopes into various numbers of fragments (from two to eight) with nearly equal size. We find that the energy released by splitting 230,232Th and 235,238U into three equal size fragments is largest. The statistical multifragmentation model (SMM) is applied to calculate the probability of different breakup channels for excited nuclei. By weighing the probability distributions of fragment multiplicity at different excitation energies, we find the peaks of energy release for 230,232Th and 235,238U are around 0.7-0.75 MeV/u at excitation energy between 1.2 and 2 MeV/u in the primary breakup process. Taking into account the secondary de-excitation processes of primary fragments with the GEMINI code, these energy peaks fall to about 0.45 MeV/u.

  8. Nitric oxide releasing acetaminophen (nitroacetaminophen).

    PubMed

    Moore, P K; Marshall, M

    2003-05-01

    The nitric oxide releasing derivative of acetaminophen (nitroacetaminophen) exhibits potent anti-inflammatory and anti-nociceptive activity in a variety of animal models. On a mol for mol basis nitroacetaminophen is some 3-20 times more potent than acetaminophen. Nitroacetaminophen exhibits little or no hepatotoxicity following administration in rat or mouse and indeed protects against the hepatotoxic activity of acetaminophen. Nitroacetaminophen does not affect blood pressure or heart rate of anaesthetised rats but has similar potency to acetaminophen as an anti-pyretic agent. The enhanced anti-inflammatory and anti-nociceptive activity of nitroacetaminophen and the reduced hepatotoxicity in these animal models is likely to be secondary to the slow release of nitric oxide from the molecule. As yet the precise molecular mechanism(s) underlying these actions of nitroacetaminophen are not clear. Evidence for inhibition of cytokine-directed formation of pro-inflammatory molecule production (e.g. COX-2, iNOS) by an effect on the NF-kappaB transduction system and/or nitrosylation (and thence inhibition) of caspase enzyme activity has been reported. Data described in this review indicate that the profile of pharmacological activity of nitroacetaminophen and acetaminophen are markedly different. The possibility that nitroacetaminophen could be an attractive alternative to acetaminophen in the clinic is discussed. PMID:12846444

  9. Foamy Virus Budding and Release

    PubMed Central

    Hütter, Sylvia; Zurnic, Irena; Lindemann, Dirk

    2013-01-01

    Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems. PMID:23575110

  10. Controlled Drug Release from Pharmaceutical Nanocarriers

    PubMed Central

    Lee, Jinhyun Hannah; Yeo, Yoon

    2014-01-01

    Nanocarriers providing spatiotemporal control of drug release contribute to reducing toxicity and improving therapeutic efficacy of a drug. On the other hand, nanocarriers face unique challenges in controlling drug release kinetics, due to the large surface area per volume ratio and the short diffusion distance. To develop nanocarriers with desirable release kinetics for target applications, it is important to understand the mechanisms by which a carrier retains and releases a drug, the effects of composition and morphology of the carrier on the drug release kinetics, and current techniques for preparation and modification of nanocarriers. This review provides an overview of drug release mechanisms and various nanocarriers with a specific emphasis on approaches to control the drug release kinetics. PMID:25684779

  11. A rapid technique for prediction of nutrient release from controlled release fertilizers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient release from soluble granular fertilizers can be modified by polymer coating to extend the total duration nutrient release up to 3 to 9 months and rate of release to match the nutrient requirement of the plant during the growing period. Hence these products are termed as “Controlled Release...

  12. Biomediated continuous release phosphate fertilizer

    DOEpatents

    Goldstein, Alan H.; Rogers, Robert D.

    1999-01-01

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed.

  13. Biomediated continuous release phosphate fertilizer

    DOEpatents

    Goldstein, A.H.; Rogers, R.D.

    1999-06-15

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed. 13 figs.

  14. Screw-released roller brake

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1999-01-01

    A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

  15. Release Data Package for Hanford Site Assessments

    SciTech Connect

    Riley, Robert G.; Lopresti, Charles A.; Engel, David W.

    2006-07-01

    Beginning in fiscal year (FY) 2003, the U.S. Department of Energy (DOE) Richland Operations Office initiated activities, including the development of data packages, to support a Hanford assessment. This report describes the data compiled in FY 2003 through 2005 to support the Release Module of the System Assessment Capability (SAC) for the updated composite analysis. This work was completed as part of the Characterization of Systems Project, part of the Remediation and Closure Science Project, the Hanford Assessments Project, and the Characterization of Systems Project managed by Pacific Northwest National Laboratory. Related characterization activities and data packages for the vadose zone and groundwater are being developed under the remediation Decision Support Task of the Groundwater Remediation Project managed by Fluor Hanford, Inc. The Release Module applies release models to waste inventory data from the Inventory Module and accounts for site remediation activities as a function of time. The resulting releases to the vadose zone, expressed as time profiles of annual rates, become source terms for the Vadose Zone Module. Radioactive decay is accounted for in all inputs and outputs of the Release Module. The Release Module is implemented as the VADER (Vadose zone Environmental Release) computer code. Key components of the Release Module are numerical models (i.e., liquid, soil-debris, cement, saltcake, and reactor block) that simulate contaminant release from the different waste source types found at the Hanford Site. The Release Module also handles remediation transfers to onsite and offsite repositories.

  16. Drug release kinetic analysis and prediction of release data via polymer molecular weight in sustained release diltiazem matrices.

    PubMed

    Adibkia, K; Ghanbarzadeh, S; Mohammadi, G; Khiavi, H Z; Sabzevari, A; Barzegar-Jalali, M

    2014-03-01

    This study was conducted to investigate the effects of HPMC (K4M and K100M) as well as tragacanth on the drug release rate of diltiazem (DLTZ) from matrix tablets prepared by direct compression method.Mechanism of drug transport through the matrices was studied by fitting the release data to the 10 kinetic models. 3 model independent parameters; i. e., mean dissolution time (MDT), mean release rate (MRR) and release rate efficacy (RE) as well as 5 time point approaches were established to compare the dissolution profiles. To find correlation between fraction of drug released and polymer's molecular weight, dissolution data were fitted into two proposed equations.All polymers could sustain drug release up to 10 h. The release data were fitted best to Peppas and Higuchi square root kinetic models considering squared correlation coefficient and mean percent error (MPE). RE and MRR were decreased when polymer to drug ratio was increased. Conversely, t60% was increased with raising polymer /drug ratio. The fractions of drug released from the formulations prepared with tragacanth were more than those formulated using the same amount of HPMC K4M and HPMC K100M.Preparation of DLTZ matrices applying HPMCK4M, HPMC K100M and tragacanth could effectively extend the drug release. PMID:23986307

  17. Helium release during shale deformation: Experimental validation

    NASA Astrophysics Data System (ADS)

    Bauer, Stephen J.; Gardner, W. Payton; Heath, Jason E.

    2016-07-01

    This work describes initial experimental results of helium tracer release monitoring during deformation of shale. Naturally occurring radiogenic 4He is present in high concentration in most shales. During rock deformation, accumulated helium could be released as fractures are created and new transport pathways are created. We present the results of an experimental study in which confined reservoir shale samples, cored parallel and perpendicular to bedding, which were initially saturated with helium to simulate reservoir conditions, are subjected to triaxial compressive deformation. During the deformation experiment, differential stress, axial, and radial strains are systematically tracked. Release of helium is dynamically measured using a helium mass spectrometer leak detector. Helium released during deformation is observable at the laboratory scale and the release is tightly coupled to the shale deformation. These first measurements of dynamic helium release from rocks undergoing deformation show that helium provides information on the evolution of microstructure as a function of changes in stress and strain.

  18. Radioactive materials released from nuclear power plants

    SciTech Connect

    Tichler, J.; Benkovitz, C.

    1981-11-01

    Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1979 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1979 release data are compared with previous year's releases in tabular form. Data covering specific radionuclides are summarized.

  19. Environmental releases for calendar year 1996

    SciTech Connect

    Greager, E.M.

    1997-07-31

    This report presents data on radioactive and nonradioactive materials released into the environment during calendar year 1996 from facilities and activities managed by the Fluor Daniel Hanford, Incorporated (formerly the Westinghouse Hanford Company) and Bechtel Hanford, Incorporated. Fluor Daniel Hanford, Incorporated provides effluent monitoring services for Bechtel Hanford, Incorporated, which includes release reporting. Both summary and detailed presentations of the environmental releases are provided. When appropriate, comparisons to data from previous years are made.

  20. Environmental releases for calendar year 1995

    SciTech Connect

    Diediker, L.P., Westinghouse Hanford

    1996-07-30

    This report presents data on radioactive and nonradioactive materials released into the environment during calendar year 1995 from facilities managed by the Westinghouse Hanford Company (WHC) and monitored by Bechtel Hanford, Incorporated (BHI). WHC provides effluent monitoring services for BHI, which includes release reporting. Both summary and detailed presentations of the environmental releases are provided. When appropriate,comparisons to data from previous years are made.

  1. Quick-release medical tape

    PubMed Central

    Laulicht, Bryan; Langer, Robert; Karp, Jeffrey M.

    2012-01-01

    Medical tape that provides secure fixation of life-sustaining and -monitoring devices with quick, easy, damage-free removal represents a longstanding unmet medical need in neonatal care. During removal of current medical tapes, crack propagation occurs at the adhesive–skin interface, which is also the interface responsible for device fixation. By designing quick-release medical tape to undergo crack propagation between the backing and adhesive layers, we decouple removal and device fixation, enabling dual functionality. We created an ordered adhesive/antiadhesive composite intermediary layer between the medical tape backing and adhesive for which we achieve tunable peel removal force, while maintaining high shear adhesion to secure medical devices. We elucidate the relationship between the spatial ordering of adhesive and antiadhesive regions to create a fully tunable system that achieves strong device fixation and quick, easy, damage-free device removal. We also described ways of neutralizing the residual adhesive on the skin and have observed that thick continuous films of adhesive are easier to remove than the thin islands associated with residual adhesive left by current medical tapes. PMID:23112196

  2. Cell type-specific activation of metabolism reveals that beta-cell secretion suppresses glucagon release from alpha-cells in rat pancreatic islets.

    PubMed

    Takahashi, Rui; Ishihara, Hisamitsu; Tamura, Akira; Yamaguchi, Suguru; Yamada, Takahiro; Takei, Daisuke; Katagiri, Hideki; Endou, Hitoshi; Oka, Yoshitomo

    2006-02-01

    Abnormal glucagon secretion is often associated with diabetes mellitus. However, the mechanisms by which nutrients modulate glucagon secretion remain poorly understood. Paracrine modulation by beta- or delta-cells is among the postulated mechanisms. Herein we present further evidence of the paracrine mechanism. First, to activate cellular metabolism and thus hormone secretion in response to specific secretagogues, we engineered insulinoma INS-1E cells using an adenovirus-mediated expression system. Expression of the Na+-dependent dicarboxylate transporter (NaDC)-1 resulted in 2.5- to 4.6-fold (P < 0.01) increases in insulin secretion in response to various tricarboxylic acid cycle intermediates. Similarly, expression of glycerol kinase (GlyK) increased insulin secretion 3.8- or 4.2-fold (P < 0.01) in response to glycerol or dihydroxyacetone, respectively. This cell engineering method was then modified, using the Cre-loxP switching system, to activate beta-cells and non-beta-cells separately in rat islets. NaDC-1 expression only in non-beta-cells, among which alpha-cells are predominant, caused an increase (by 1.8-fold, P < 0.05) in glucagon secretion in response to malate or succinate. However, the increase in glucagon release was prevented when NaDC-1 was expressed in whole islets, i.e., both beta-cells and non-beta-cells. Similarly, an increase in glucagon release with glycerol was observed when GlyK was expressed only in non-beta-cells but not when it was expressed in whole islets. Furthermore, dicarboxylates suppressed basal glucagon secretion by 30% (P < 0.05) when NaDC-1 was expressed only in beta-cells. These data demonstrate that glucagon secretion from rat alpha-cells depends on beta-cell activation and provide insights into the coordinated mechanisms underlying hormone secretion from pancreatic islets.

  3. Somatodendritic dopamine release: recent mechanistic insights

    PubMed Central

    Rice, Margaret E.; Patel, Jyoti C.

    2015-01-01

    Dopamine (DA) is a key transmitter in motor, reward and cogitative pathways, with DA dysfunction implicated in disorders including Parkinson's disease and addiction. Located in midbrain, DA neurons of the substantia nigra pars compacta project via the medial forebrain bundle to the dorsal striatum (caudate putamen), and DA neurons in the adjacent ventral tegmental area project to the ventral striatum (nucleus accumbens) and prefrontal cortex. In addition to classical vesicular release from axons, midbrain DA neurons exhibit DA release from their cell bodies and dendrites. Somatodendritic DA release leads to activation of D2 DA autoreceptors on DA neurons that inhibit their firing via G-protein-coupled inwardly rectifying K+ channels. This helps determine patterns of DA signalling at distant axonal release sites. Somatodendritically released DA also acts via volume transmission to extrasynaptic receptors that modulate local transmitter release and neuronal activity in the midbrain. Thus, somatodendritic release is a pivotal intrinsic feature of DA neurons that must be well defined in order to fully understand the physiology and pathophysiology of DA pathways. Here, we review recent mechanistic aspects of somatodendritic DA release, with particular emphasis on the Ca2+ dependence of release and the potential role of exocytotic proteins. PMID:26009764

  4. Controlled release of thyrotropin releasing hormone from microspheres: evaluation of release profiles and pharmacokinetics after subcutaneous administration.

    PubMed

    Heya, T; Mikura, Y; Nagai, A; Miura, Y; Futo, T; Tomida, Y; Shimizu, H; Toguchi, H

    1994-06-01

    The drug-release kinetics of thyrotropin releasing hormone (TRH) containing copoly(dl-lactic/glycolic acid) (PLGA) microspheres were evaluated both in vitro and in vivo. The drug was encapsulated in PLGA using an in-water drying method through a water in oil in water emulsion. The drug release from the PLGA microspheres in vitro correlated well with that in vivo, and pseudo-zero-order release kinetics were observed. The pharmacokinetics of TRH following administration of this controlled-release parenteral dosage form have been also examined in rats. Following a transient increase in the plasma level due to an initial burst, steady-state plasma levels were observed. The duration of drug release estimated from the plasma level was comparable with the results in the in vitro and in vivo release studies. The steady-state plasma levels correlated well with the levels predicted from the pharmacokinetic parameters following a single subcutaneous or intravenous injection of TRH solution. The results of this study confirm the previously reported in vivo sustained release of TRH achieved with this drug-delivery system. PMID:9120809

  5. Summary Profiles of Hanford Effluent Release Data

    SciTech Connect

    KM Tominey; MK White

    1999-01-07

    Hanford publishes extensive estimates of their offsite releases of various chemical and radiological species annuaIly. In this report we examine using these estimates to develop additional insight into how effectively such releases of hazardous materials are being controlled at Hanford. Historical estimates of airborne and surface water releases of selected contaminants are compared with estimates of the overall Site inventory of those contaminants and with the corresponding release limits and background levels. These comparisons are also examined over a five-year period (1993 to 1997) to determine how these releases have changed during that time. Most of the waste management and environmental restoration activities under way at Hanford are intended to provide final, permanent disposition of the Site's inventory of hazardous materials, with the ultimate objective of ensuring that risks to the public and the environment are controlled to an acceptable level. An important consideration during the conduct of these activities is prott%ting the public and the environment while accomplishing the longer-term ~~ objectives. The amounts of hazardous materials that are being released to the air or surface water while waste management and environmental activities are being conducted is one important measure of their overall effectiveness. The comparisons described in this report indicate that measures to control the release of the selected contaminants from the Hanford Site are, and have been, veryeffective. The amounts of these materials released to surface water and air are very small compared with background and regulatory limits and smaller still considering the inventories" under management. Comparisons of annual releases ranged from slightly over background to five orders of magnitude below background levels (e.g., l/10,000* of background levels), and up to 14 orders of magnitude less than estimates of Site inventories. Annual releases for these contaminants

  6. Morphology of Gas Release in Physical Simulants

    SciTech Connect

    Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

    2014-07-03

    This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

  7. 28 CFR 571.22 - Release clothing and transportation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Release clothing and transportation. 571... AND RELEASE RELEASE FROM CUSTODY Release Gratuities, Transportation, and Clothing § 571.22 Release clothing and transportation. (a) Staff shall provide release clothing appropriate for the time of year...

  8. 28 CFR 571.22 - Release clothing and transportation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Release clothing and transportation. 571... AND RELEASE RELEASE FROM CUSTODY Release Gratuities, Transportation, and Clothing § 571.22 Release clothing and transportation. (a) Staff shall provide release clothing appropriate for the time of year...

  9. 28 CFR 571.22 - Release clothing and transportation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Release clothing and transportation. 571... AND RELEASE RELEASE FROM CUSTODY Release Gratuities, Transportation, and Clothing § 571.22 Release clothing and transportation. (a) Staff shall provide release clothing appropriate for the time of year...

  10. 28 CFR 571.22 - Release clothing and transportation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Release clothing and transportation. 571... AND RELEASE RELEASE FROM CUSTODY Release Gratuities, Transportation, and Clothing § 571.22 Release clothing and transportation. (a) Staff shall provide release clothing appropriate for the time of year...

  11. 28 CFR 571.22 - Release clothing and transportation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Release clothing and transportation. 571... AND RELEASE RELEASE FROM CUSTODY Release Gratuities, Transportation, and Clothing § 571.22 Release clothing and transportation. (a) Staff shall provide release clothing appropriate for the time of year...

  12. Ten Ways to Get Attention with Your Press Releases.

    ERIC Educational Resources Information Center

    Van Kooten, Valerie

    1994-01-01

    Recommends 10 steps that can increase chances of having press release published. Advises readers to use required format; determine what constitutes news; keep release short; include contact person in release; incorporate good quotes; send releases to right person; understand that release will be edited; time arrival of release; follow up with…

  13. Teach with Databases: Toxics Release Inventory. [Multimedia].

    ERIC Educational Resources Information Center

    Barracato, Jay; Spooner, Barbara

    This curriculum unit provides students with real world applications of science as it pertains to toxic releases into the environment. This boxed package contains the Toxics Release Inventory (TRI) Teacher's Guide, TRI Database Basics guide, comprehensive TRI compact disk with user's guide, "Getting Started: A Guide to Bringing Environmental…

  14. 10 CFR 850.31 - Release criteria.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Release criteria. 850.31 Section 850.31 Energy DEPARTMENT OF ENERGY CHRONIC BERYLLIUM DISEASE PREVENTION PROGRAM Specific Program Requirements § 850.31 Release criteria. (a) The responsible employer must clean beryllium-contaminated equipment and other items to...

  15. 10 CFR 850.31 - Release criteria.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Release criteria. 850.31 Section 850.31 Energy DEPARTMENT OF ENERGY CHRONIC BERYLLIUM DISEASE PREVENTION PROGRAM Specific Program Requirements § 850.31 Release criteria. (a) The responsible employer must clean beryllium-contaminated equipment and other items to...

  16. 27 CFR 27.185 - Customs release.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Customs release. 27.185... Distilled Spirits From Customs Custody Free of Tax for Use of the United States § 27.185 Customs release. (a) Upon receipt of appropriate customs entry and a photocopy of a permit, Form 5150.33 or...

  17. Contamination surveys for release of material

    SciTech Connect

    Durham, J.S.; Johnson, M.L.; Gardner, D.L.

    1994-05-01

    This report describes, and presents the technical basis for, a methodology for performing instrument surveys to release material from radiological control, including release to controlled areas and release from radiological control. The methodology is based on a fast scan survey, a large-area wipe survey, and a series of statistical, fixed measurements. The methodology meets the requirements of the US Department of Energy Radiological Control Manual (RadCon Manual) (DOE 1994) and DOE Order 5400.5 (DOE 1990) for release of material in less time than is required by a conventional scan survey. Implementation of the proposed methodology with a confidence interval of 67% will meet the material release requirements. The material evaluation process will allow material that has not been exposed to contamination to be released from radiological control without a survey. For potential radioactive contaminants that are not reserved in DOE Order 5400.5, the methodology will allow material to be released from radiological control. For other radionuclides, with the exception of some difficult-to-detect radionuclides, material may be released for controlled use. Compared with current techniques, the proposed methodology will reduce the amount of time required to perform surveys.

  18. 48 CFR 2905.404 - Release procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... release long-range acquisition estimates under the conditions in FAR 5.404-1. ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Release procedures. 2905.404 Section 2905.404 Federal Acquisition Regulations System DEPARTMENT OF LABOR ACQUISITION...

  19. Method for releasing hydrogen from ammonia borane

    SciTech Connect

    Varma, Arvind; Diwan, Moiz; Shafirovich, Evgeny; Hwang, Hyun-Tae; Al-Kukhun, Ahmad

    2013-02-19

    A method of releasing hydrogen from ammonia borane is disclosed. The method comprises heating an aqueous ammonia borane solution to between about 80-135.degree. C. at between about 14.7 and 200 pounds per square inch absolute (psia) to release hydrogen by hydrothermolysis.

  20. In the Stocks: Perilous Press Releases.

    ERIC Educational Resources Information Center

    Morton, Linda P.; Loving, Bill

    1994-01-01

    Reviews some of the legal responsibilities of public relations practitioners in the preparation of press releases. Discusses legal criteria for judging the fraudulence of press releases and discusses the timeframe for fraudulent action. Concludes with lessons that practitioners need to understand. (SR)

  1. 21 CFR 181.28 - Release agents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Release agents. 181.28 Section 181.28 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients § 181.28 Release agents....

  2. 49 CFR 236.790 - Release, time.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Release, time. 236.790 Section 236.790... Release, time. A device used to prevent the operation of an operative unit until after the expiration of a predetermined time interval after the device has been actuated....

  3. BLOOD TRIGGERED RAPID RELEASE POROUS NANOCAPSULES

    PubMed Central

    Gustafson, Tiffany P.; Dergunov, Sergey A.; Akers, Walter J.; Cao, Qian; Magalotti, Selena; Achilefu, Samuel; Pinkhassik, Eugene; Berezin, Mikhail Y.

    2013-01-01

    Rapid-release drug delivery systems present a new paradigm in emergency care treatments. Such systems combine a long shelf life with the ability to provide a significant dose of the drug to the bloodstream in the shortest period of time. Until now, development of delivery formulations has concentrated on slow release systems to ensure a steady concentration of the drug. To address the need for quick release system, we created hollow polyacrylate nanocapsules with nanometer-thin porous walls. Burst release occurs upon interaction with blood components that leads to escape of the cargo. The likely mechanism of release involves a conformational change of the polymer shell caused by binding albumin. To demonstrate this concept, a near-infrared fluorescent dye indocyanine green (ICG) was incorporated inside the nanocapsules. ICG-loaded nanocapsules demonstrated remarkable shelf life in aqueous buffers with no release of ICG for twelve months. Rapid release of the dye was demonstrated first in vitro using albumin solution and serum. SEM and light scattering analysis demonstrated the retention of the nanocapsule architecture after the release of the dye upon contact with albumin. In vivo studies using fluorescence lifetime imaging confirmed quick discharge of ICG from the nanocapsules following intravenous injection. PMID:23606942

  4. Releasable Asbestos Field Sampler (RAFS) Operation Manual

    EPA Science Inventory

    The Releasable Asbestos Field Sampler (RAFS) is a field instrument that provides an in-situ measurement of asbestos releasability from consistent and reproducible mechanical agitation of the source material such as soil. The RAFS was designed to measure concentration (asbestos st...

  5. Controlled drug release from hydrogel nanoparticle networks.

    PubMed

    Huang, Gang; Gao, Jun; Hu, Zhibing; St John, John V; Ponder, Bill C; Moro, Dan

    2004-02-10

    Monodisperse nanoparticles of poly-N-isopropylacrylamide-co-allylamine (PNIPAM-co-allylamine) and PNIPAM-co-acrylic acid (PNIPAM-co-AA) were synthesized. The close-packed PNIPAM-co-allylamine and PNIPAM-co-AA nanoparticles were converted to three-dimensional gel networks by covalently crosslinking neighboring particles at room temperature and neutral pH using glutaric dialdehyde and adipic acid dihydrazide, respectively. Controlled release studies were conducted using dextran markers of various molecular weights as model macromolecular drugs. Release was quantified under various physical conditions, including a range of temperatures and dextran molecular weights. Dextran, entrapped in cavities in the nanoparticle network, was released with a rate regulated by their molecular weights and cavity size. No release from a conventional bulk PNIPAM gel, with high crosslinking density, was observed. The rate of release from the PNIPAM-co-allylamine network was temperature-dependent, being much faster at room temperature than that at human body temperature. In contrast, release of low molecular weight dextrans from the PNIPAM-co-AA network showed a temperature-independent release profile. These nanoparticle networks have several advantages over conventional bulk gels for controlling the release of high molecular weight biomolecules. PMID:14744482

  6. Serotonin release varies with brain tryptophan levels

    NASA Technical Reports Server (NTRS)

    Schaechter, Judith D.; Wurtman, Richard J.

    1990-01-01

    This study examines directly the effects on serotonin release of varying brain tryptophan levels within the physiologic range. It also addresses possible interactions between tryptophan availability and the frequency of membrane depolarization in controlling serotonin release. We demonstrate that reducing tryptophan levels in rat hypothalamic slices (by superfusing them with medium supplemented with 100 microM leucine) decreases tissue serotonin levels as well as both the spontaneous and the electrically-evoked serotonin release. Conversely, elevating tissue tryptophan levels (by superfusing slices with medium supplemented with 2 microM tryptophan) increases both the tissue serotonin levels and the serotonin release. Serotonin release was found to be affected independently by the tryptophan availability and the frequency of electrical field-stimulation (1-5 Hz), since increasing both variables produced nearly additive increases in release. These observations demonstrate for the first time that both precursor-dependent elevations and reductions in brain serotonin levels produce proportionate changes in serotonin release, and that the magnitude of the tryptophan effect is unrelated to neuronal firing frequency. The data support the hypothesis that serotonin release is proportionate to intracellular serotonin levels.

  7. 40 CFR 227.28 - Release zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Release zone. 227.28 Section 227.28 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.28 Release zone....

  8. 40 CFR 227.28 - Release zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Release zone. 227.28 Section 227.28 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.28 Release zone....

  9. 40 CFR 227.28 - Release zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Release zone. 227.28 Section 227.28 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.28 Release zone....

  10. 40 CFR 227.28 - Release zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Release zone. 227.28 Section 227.28 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.28 Release zone....

  11. Extended-release methylphenidate (Ritalin LA).

    PubMed

    Lyseng-Williamson, Katherine A; Keating, Gillian M

    2002-01-01

    An extended-release formulation of methylphenidate (Ritalin LA), a CNS stimulant that inhibits dopamine and noradrenaline (norepinephrine) reuptake into presynaptic neurons, has been developed for use in patients with attention deficit/hyperactivity disorder (ADHD). In children with ADHD and healthy male adults, extended-release methylphenidate 20mg was rapidly absorbed and demonstrated two distinct peak plasma concentrations approximately 4 hours apart. The absorption pharmacokinetics of extended-release methylphenidate 20mg, which closely mimics those of immediate-release methylphenidate 10mg given in two doses 4 hours apart, permits once-daily administration. In a 2-week randomised, double-blind, placebo-controlled trial in 134 evaluable children aged 6 to 12 years with ADHD, symptoms improved to a significantly greater extent with extended-release methylphenidate 10 to 40mg once daily than with placebo. Extended-release methylphenidate improved both inattention and hyperactivity symptoms and was effective in children with combined- (inattentive and hyperactive/impulsive) type or predominantly inattentive-type ADHD. In clinical trials, the safety and tolerability profiles of extended-release methylphenidate were consistent with that of the immediate-release formulation.

  12. Automated code compilation via the Release Manager

    NASA Astrophysics Data System (ADS)

    Golpayegani, N.

    2006-07-01

    GLAST performs automated builds of its C++ code base. These builds reflect a three-tiered approach to code development, allowing us to test and create releases, as well as get a view of new code submissions that will eventually make it into releases. The program responsible for these automated builds is called the Release Manager. It is based on code originally written by Alex Schlessinger. Its main purpose is to provide rapid feedback for developers when code changes occur. It consists of three loosely connected pieces: The batch submission interface, the Workflow manager, and the Release Manager scripts. The batch submission interface is responsible for keeping track of submitted batch jobs and notifying users/programs using various methods when jobs change status. The Release Manager relies heavily on this interface to allow code builds to happen on demand and in parallel. The workflow manager is a generic program responsible for moving from one state to another based on criteria defined. These states are executed using the batch submission program. Finally the Release Manager consists of scripts that are registered as different states in the Workflow Manager. The Release Manager is currently able to run on Linux and Windows. It uses a MySQL database to record its information. It is currently tightly tied to GLAST's build tool, CMT. Other purposes of the Release Manager are to create source packages for developers and binary packages for end users.

  13. 28 CFR 2.83 - Release planning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Release planning. 2.83 Section 2.83 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS District of Columbia Code: Prisoners and Parolees §...

  14. 19 CFR 142.48 - Release procedure.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... measure, and the C-4 Code will be printed on the invoice and the manifest document and, when other agency documentation is presented, may be printed on that documentation. The invoice shall be returned to the entry.... The returned invoice with the release data shall be the release notification to non-ABI...

  15. 19 CFR 142.48 - Release procedure.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... measure, and the C-4 Code will be printed on the invoice and the manifest document and, when other agency documentation is presented, may be printed on that documentation. The invoice shall be returned to the entry.... The returned invoice with the release data shall be the release notification to non-ABI...

  16. 10 CFR 850.31 - Release criteria.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Release criteria. 850.31 Section 850.31 Energy DEPARTMENT OF ENERGY CHRONIC BERYLLIUM DISEASE PREVENTION PROGRAM Specific Program Requirements § 850.31 Release... the equipment or item and its future use and the nature of the beryllium contamination. (c)...

  17. 10 CFR 850.31 - Release criteria.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Release criteria. 850.31 Section 850.31 Energy DEPARTMENT OF ENERGY CHRONIC BERYLLIUM DISEASE PREVENTION PROGRAM Specific Program Requirements § 850.31 Release... the equipment or item and its future use and the nature of the beryllium contamination. (c)...

  18. 10 CFR 850.31 - Release criteria.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Release criteria. 850.31 Section 850.31 Energy DEPARTMENT OF ENERGY CHRONIC BERYLLIUM DISEASE PREVENTION PROGRAM Specific Program Requirements § 850.31 Release... the equipment or item and its future use and the nature of the beryllium contamination. (c)...

  19. Nitric Oxide Release Part I. Macromolecular Scaffolds

    PubMed Central

    Riccio, Daniel A.; Schoenfisch, Mark H.

    2012-01-01

    Summary The roles of nitric oxide (NO) in physiology and pathophysiology merit the use of NO as a therapeutic for certain biomedical applications. Unfortunately, limited NO payloads, too rapid NO release, and the lack of targeted NO delivery have hindered the clinical utility of NO gas and low molecular weight NO donor compounds. A wide-variety of NO-releasing macromolecular scaffolds has thus been developed to improve NO’s pharmacological potential. In this tutorial review, we provide an overview of the most promising NO release scaffolds including protein, organic, inorganic, and hybrid organic-inorganic systems. The NO release vehicles selected for discussion were chosen based on their enhanced NO storage, tunable NO release characteristics, and potential as therapeutics. PMID:22362355

  20. Ecological release in White Sands lizards

    PubMed Central

    Roches, S Des; Robertson, J M; Harmon, L J; Rosenblum, E B

    2011-01-01

    Ecological opportunity is any change that allows populations to escape selection from competition and predation. After encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. We identified ecological opportunity and tested for ecological release in three lizard colonists of White Sands, New Mexico (Sceloporus undulatus, Holbrookia maculata, and Aspidoscelis inornata). First, we provide evidence for ecological opportunity by demonstrating reduced species richness and abundance of potential competitors and predators at White Sands relative to nearby dark soils habitats. Second, we characterize ecological release at White Sands by demonstrating density compensation in the three White Sands lizard species and expanded resource use in White Sands S. undulatus. Contrary to predictions from ecological release models, we observed directional trait change but not increased trait variation in S. undulatus. Our results suggest that ecological opportunity and ecological release can be identified in natural populations, especially those that have recently colonized isolated ecosystems. PMID:22393523