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Sample records for acid cycle tca

  1. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Differentiates the tricarboxylic acid (TCA) cycle (or Krebs cycle) from glycolysis, and describes the bridge between the two as being the conversion of pyruvate into acetyl coenzyme A. Discusses the eight steps in the TCA cycle, the results of isotopic labeling experiments, and the net effects of the TCA cycle. (TW)

  2. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    PubMed

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass. PMID:25342454

  3. Application of citrate as a tricarboxylic acid (TCA) cycle intermediate, prevents diabetic-induced heart damages in mice

    PubMed Central

    Liang, Qianqian; Wang, Baoyu; Pang, Lingxia; Wang, Youpei; Zheng, Meiqin; Wang, Qing; Yan, Jingbin; Xu, Jinzhong

    2016-01-01

    Objective(s): Higher cellular reactive oxygen species (ROS) levels is important in reducing cellular energy charge (EC) by increasing the levels of key metabolic protein, and nitrosative modifications, and have been shown to damage the cardiac tissue of diabetic mice. However, the relation between energy production and heart function is unclear. Materials and Methods: Streptozotocin (STZ, 150 mg/kg body weight) was injected intraperitoneally once to mice that had been fasted overnight for induction of diabetes. After diabetic induction, mice received citrate (5 µg/kg) through intraperitoneal injection every other day for 5 weeks. The caspase-3, plasminogen activator inhibitor 1 (PAI1), protein kinase B (PKB), commonly known as AKT and phosphorylated-AKT (p-AKT) proteins were examined to elucidate inflammation and apoptosis in the heart. For histological analysis, heart samples were fixed with 10% formalin and stained with hematoxylin-eosin (HE) and Sirius red to assess pathological changes and fibrosis. The expression levels[AGA1] of marker proteins, tyrosine nitration, activity of ATP synthase and succinyl-CoA3-ketoacid coenzyme A transferase-1 (SCOT), and EC were measured. Results: Intraperitoneal injection of citrate significantly reduced caspase-3 and PAI-1 protein levels and increased p-AKT level on the 5th week; EC in the heart was found to be increased as well. Further, the expression level, activity, and tyrosine nitration of ATP synthase and SCOT were not affected after induction of diabetes. Conclusion: Results indicate that application of citrate, a tricarboxylic acid (TCA) cycle intermediate, might alleviate cardiac dysfunction by reducing cardiac inflammation, apoptosis, and increasing cardiac EC. PMID:27096063

  4. Contribution of the tricarboxylic acid (TCA) cycle and the glyoxylate shunt in Saccharomyces cerevisiae to succinic acid production during dough fermentation.

    PubMed

    Rezaei, Mohammad N; Aslankoohi, Elham; Verstrepen, Kevin J; Courtin, Christophe M

    2015-07-01

    Succinic acid produced by yeast during bread dough fermentation can significantly affect the rheological properties of the dough. By introducing mutations in the model S288C yeast strain, we show that the oxidative pathway of the TCA cycle and the glyoxylate shunt contribute significantly to succinic acid production during dough fermentation. More specifically, deletion of ACO1 and double deletion of ACO1 and ICL1 resulted in a 36 and 77% decrease in succinic acid levels in fermented dough, respectively. Similarly, double deletion of IDH1 and IDP1 decreased succinic acid production by 85%, while also affecting the fermentation rate. By contrast, double deletion of SDH1 and SDH2 resulted in a two-fold higher succinic acid accumulation compared to the wild-type. Deletion of fumarate reductase activity (FRD1 and OSM1) in the reductive pathway of the TCA cycle did not affect the fermentation rate and succinic acid production. The changes in the levels of succinic acid produced by mutants Δidh1Δidp1 (low level) and Δsdh1Δsdh2 (high level) in fermented dough only resulted in small pH differences, reflecting the buffering capacity of dough at a pH of around 5.1. Moreover, Rheofermentometer analysis using these mutants revealed no difference in maximum dough height and gas retention capacity with the dough prepared with S288C. The impact of the changed succinic acid profile on the organoleptic or antimicrobial properties of bread remains to be demonstrated. PMID:25828707

  5. Dysfunctional TCA-Cycle Metabolism in Glutamate Dehydrogenase Deficient Astrocytes.

    PubMed

    Nissen, Jakob D; Pajęcka, Kamilla; Stridh, Malin H; Skytt, Dorte M; Waagepetersen, Helle S

    2015-12-01

    Astrocytes take up glutamate in the synaptic area subsequent to glutamatergic transmission by the aid of high affinity glutamate transporters. Glutamate is converted to glutamine or metabolized to support intermediary metabolism and energy production. Glutamate dehydrogenase (GDH) and aspartate aminotransferase (AAT) catalyze the reversible reaction between glutamate and α-ketoglutarate, which is the initial step for glutamate to enter TCA cycle metabolism. In contrast to GDH, AAT requires a concomitant interconversion of oxaloacetate and aspartate. We have investigated the role of GDH in astrocyte glutamate and glucose metabolism employing siRNA mediated knock down (KD) of GDH in cultured astrocytes using stable and radioactive isotopes for metabolic mapping. An increased level of aspartate was observed upon exposure to [U-(13) C]glutamate in astrocytes exhibiting reduced GDH activity. (13) C Labeling of aspartate and TCA cycle intermediates confirmed that the increased amount of aspartate is associated with elevated TCA cycle flux from α-ketoglutarate to oxaloacetate, i.e. truncated TCA cycle. (13) C Glucose metabolism was elevated in GDH deficient astrocytes as observed by increased de novo synthesis of aspartate via pyruvate carboxylation. In the absence of glucose, lactate production from glutamate via malic enzyme was lower in GDH deficient astrocytes. In conclusions, our studies reveal that metabolism via GDH serves an important anaplerotic role by adding net carbon to the TCA cycle. A reduction in GDH activity seems to cause the astrocytes to up-regulate activity in pathways involved in maintaining the amount of TCA cycle intermediates such as pyruvate carboxylation as well as utilization of alternate substrates such as branched chain amino acids. PMID:26221781

  6. High night temperature strongly impacts TCA cycle, amino acid and polyamine biosynthetic pathways in rice in a sensitivity-dependent manner

    PubMed Central

    Glaubitz, Ulrike; Erban, Alexander; Kopka, Joachim; Hincha, Dirk K.; Zuther, Ellen

    2015-01-01

    Global climate change combined with asymmetric warming can have detrimental effects on the yield of crop plants such as rice (Oryza sativa L.). Little is known about metabolic responses of rice to high night temperature (HNT) conditions. Twelve cultivars with different HNT sensitivity were used to investigate metabolic changes in the vegetative stage under HNT compared to control conditions. Central metabolism, especially TCA cycle and amino acid biosynthesis, were strongly affected particularly in sensitive cultivars. Levels of several metabolites were correlated with HNT sensitivity. Furthermore, pool sizes of some metabolites negatively correlated with HNT sensitivity under control conditions, indicating metabolic pre-adaptation in tolerant cultivars. The polyamines putrescine, spermidine and spermine showed increased abundance in sensitive cultivars under HNT conditions. Correlations between the content of polyamines and 75 other metabolites indicated metabolic shifts from correlations with sugar-phosphates and 1-kestose under control to correlations with sugars and amino and organic acids under HNT conditions. Increased expression levels of ADC2 and ODC1, genes encoding enzymes catalysing the first committed steps of putrescine biosynthesis, were restricted to sensitive cultivars under HNT. Additionally, transcript levels of eight polyamine biosynthesis genes were correlated with HNT sensitivity. Responses to HNT in the vegetative stage result in distinct differences between differently responding cultivars with a dysregulation of central metabolism and an increase of polyamine biosynthesis restricted to sensitive cultivars under HNT conditions and a pre-adaptation of tolerant cultivars already under control conditions with higher levels of potentially protective compatible solutes. PMID:26208642

  7. Mitochondrial engineering of the TCA cycle for fumarate production.

    PubMed

    Chen, Xiulai; Dong, Xiaoxiang; Wang, Yuancai; Zhao, Zihao; Liu, Liming

    2015-09-01

    Microbial fumarate production from renewable feedstock is a promising and sustainable alternative to petroleum-based chemical synthesis. Here, mitochondrial engineering was used to construct the oxidative pathway for fumarate production starting from the TCA cycle intermediate α-ketoglutarate in Candida glabrata. Accordingly, α-ketoglutarate dehydrogenase complex (KGD), succinyl-CoA synthetase (SUCLG), and succinate dehydrogenase (SDH) were selected to be manipulated for strengthening the oxidative pathway, and the engineered strain T.G-K-S-S exhibited increased fumarate biosynthesis (1.81 g L(-1)). To further improve fumarate production, the oxidative route was optimized. First, three fusion proteins KGD2-SUCLG2, SUCLG2-SDH1 and KGD2-SDH1 were constructed, and KGD2-SUCLG2 led to improved fumarate production (4.24 g L(-1)). In addition, various strengths of KGD2-SUCLG2 and SDH1 expression cassettes were designed by combinations of promoter strengths and copy numbers, resulting in a large increase in fumarate production (from 4.24 g L(-1) to 8.24 g L(-1)). Then, through determining intracellular amino acids and its related gene expression levels, argininosuccinate lyase in the urea cycle was identified as the key factor for restricting higher fumarate production. Correspondingly, after overexpression of it, the fumarate production was further increased to 9.96 g L(-1). Next, two dicarboxylic acids transporters facilitated an improvement of fumarate production, and, as a result, the final strain T.G-KS(H)-S(M)-A-2S reached fumarate titer of 15.76 g L(-1). This strategy described here paves the way to the development of an efficient pathway for microbial production of fumarate. PMID:25708514

  8. Prebiotic Metabolisms: Photo catalysis of the rTCA cycle by sphalerite colloids

    NASA Astrophysics Data System (ADS)

    Mangiante, D. M.; Bowen, B.; Northen, T.; Banfield, J. F.

    2010-12-01

    Explorations of mineral catalyzed reverse tricarboxylic acid (rTCA) cycle reactions provide a window into possible mechanisms for prebiotic metabolisms and the origins of life. The excitation of nano-scale semiconducting sphalerite minerals by ultra-violate light results in reducing electrons capable of catalyzing the reduction reactions present in the rTCA cycle. Current literature has utilized ion chromatography methods to characterize catalysis of two of the five redox active rTCA cycle compounds with high yield. This technique is unable to produce the untargeted analysis required to anticipate the myriad side reactions driven by excited photoelectrons and their ensuing radicals. By employing liquid chromatography coupled to mass spectrometry (LC-MS) we can examine the complete range of metabolites present across a reaction time series. The three dimensional LC-MS data set allows for the qualitative determination of individual metabolite features, while the comparison of intensities yields quantitative rates. These results allow us to describe the complete set of reactions resultant from a single rTCA cycle organic acid on a photo-activated sphalerite surface and provide a possible mechanism for how metabolic pathways could operate in enzyme free environments.

  9. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  10. A Possibility for Piece-wise Ignitions of a TCA Cycle in a Prebiotic Hydrothermal Environment

    NASA Astrophysics Data System (ADS)

    Nemoto, A.; Ikeya, R.; Imai, E.; Hatori, K.; Honda, H.; Matsuno, K.

    We previously reported that formic and acetic acids were synthesized from the mixture of carbon dioxide and water in the presence of heated metal oxide serving as a catalyst (1). Fixation of carbon dioxide and monoxide could have been conceivable in the hydrothermal environment in the primitive ocean. We then considered a possibility of synthesizing major metabolites appearing in a TCA cycle in prebiotic conditions. Focused in this attempt was the vicinity of hydrothermal vents in the primitive ocean. We used a flow reactor to simulate hydrothermal circulation of seawater through hot vents (2). The experimental conditions we chose were that the hot chamber at 200 °C was connected to the cold chamber at 0 °C through a thin nozzle of its diameter 0.8 mm. The total volume of the reaction solution was 500 mL. The fluid was circulated through the flow reactor at the rate of 8 mL / min. As an initial attempt, we prepared the solution of acetic and formic acids. When iron chloride and copper sulfide were present in the solution, the products precipitated on the filter placed in the low-temperature chamber included di-carboxylic acids such as malic acid. We then proceeded to the reaction solution dissolving three different kinds of carboxylic acids, namely, succinate, fumarate, and oxoglutarate. We found that malic acid was in the solution after the operation of the flow-reactor. Formation and transformation of carboxylic acids were observed in our flow reactor. These observations, when combined together, may suggest a possibility of piece-wise ignitions of a TCA cycle even in the prebiotic ocean on the primitive earth. References (1) R. Terada, E. Imai, H. Honda, K. Hatori, and K. Matsuno.: Viva Origino 27, 197-208(1999). (2) E. Imai, H. Honda, K. Hatori, A. Brack, and K. Matsuno.: Science 283, 831-833(1999).

  11. Real Time Molecular Imaging of TCA Cycle Metabolism in vivo By Hyperpolarized 1-13C Diethyl Succinate

    PubMed Central

    Zacharias, Niki M.; Chan, Henry R.; Sailasuta, Napapon; Ross, Brian D.

    2011-01-01

    The Krebs tricarboxylic acid cycle (TCA) is central to metabolic energy production and is known to be altered in many disease states. Real time molecular imaging of TCA cycle in vivo will be important in understanding the metabolic basis of several diseases. Positron emission tomography (PET) using FDG-glucose (2-[18F]fluoro-2-deoxy-D-glucose) is already being used as a metabolic imaging agent in clinics. However, FDG-glucose does not reveal anything past glucose uptake and phosphorylation. We have developed a new metabolic imaging agent, hyperpolarized diethyl 1-13C 2,3-d2 succinate, that allows for real time in vivo imaging and spectroscopy of the TCA cycle. Diethyl succinate can be hyperpolarized using parahydrogen induced polarization (PHIP) in an aqueous solution with signal enhancement of 5000 compared to Boltzmann polarization. 13C magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) were achieved in vivo seconds after injection of 10 to 20 μmol of hyperpolarized diethyl succinate into normal mice. The downstream metabolites of hyperpolarized diethyl succinate were identified in vivo as malate, succinate, fumarate and aspartate. The metabolism of diethyl succinate was altered after exposing the animal to 3-nitropropionate, a known irreversible inhibitor of succinate dehydrogenase. Based on our results, hyperpolarized diethyl succinate allows for in real time in vivo MRI and MRS with a high signal to noise ratio and with visualization of multiple steps of the TCA cycle. Hyperpolarization of diethyl succinate and its in vivo applications may reveal an entirely new regime wherein the local status of TCA cycle metabolism is interrogated on the time scale of seconds to minutes with unprecedented chemical specificity and MR sensitivity. PMID:22146049

  12. TCA Cycle and Mitochondrial Membrane Potential Are Necessary for Diverse Biological Functions.

    PubMed

    Martínez-Reyes, Inmaculada; Diebold, Lauren P; Kong, Hyewon; Schieber, Michael; Huang, He; Hensley, Christopher T; Mehta, Manan M; Wang, Tianyuan; Santos, Janine H; Woychik, Richard; Dufour, Eric; Spelbrink, Johannes N; Weinberg, Samuel E; Zhao, Yingming; DeBerardinis, Ralph J; Chandel, Navdeep S

    2016-01-21

    Mitochondrial metabolism is necessary for the maintenance of oxidative TCA cycle function and mitochondrial membrane potential. Previous attempts to decipher whether mitochondria are necessary for biological outcomes have been hampered by genetic and pharmacologic methods that simultaneously disrupt multiple functions linked to mitochondrial metabolism. Here, we report that inducible depletion of mitochondrial DNA (ρ(ο) cells) diminished respiration, oxidative TCA cycle function, and the mitochondrial membrane potential, resulting in diminished cell proliferation, hypoxic activation of HIF-1, and specific histone acetylation marks. Genetic reconstitution only of the oxidative TCA cycle function specifically in these inducible ρ(ο) cells restored metabolites, resulting in re-establishment of histone acetylation. In contrast, genetic reconstitution of the mitochondrial membrane potential restored ROS, which were necessary for hypoxic activation of HIF-1 and cell proliferation. These results indicate that distinct mitochondrial functions associated with respiration are necessary for cell proliferation, epigenetics, and HIF-1 activation. PMID:26725009

  13. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits

    PubMed Central

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity. PMID:26042830

  14. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits.

    PubMed

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity. PMID:26042830

  15. IRIS Toxicological Review of Trichloroacetic Acid (TCA) (Interagency Science Discussion Draft)

    EPA Science Inventory

    EPA is releasing the draft report, Toxicological Review of Trichloroacetic Acid (TCA), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment Development ...

  16. IRIS Toxicological Review of Trichloroacetic Acid (TCA) (Interagency Science Consultation Draft)

    EPA Science Inventory

    On September 24, 2009, the Toxicological Review of Trichloroacetic Acid (TCA) and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies an...

  17. Glucose-independent glutamine metabolism via TCA cycling for proliferation and survival in B-cells

    PubMed Central

    Le, Anne; Lane, Andrew N.; Hamaker, Max; Bose, Sminu; Gouw, Arvin; Barbi, Joseph; Tsukamoto, Takashi; Rojas, Camilio J.; Slusher, Barbara S.; Zhang, Haixia; Zimmerman, Lisa J.; Liebler, Daniel C.; Slebos, Robbert J.C.; Lorkiewicz, Pawel K.; Higashi, Richard M.; Fan, Teresa W. M.; Dang, Chi V.

    2012-01-01

    Summary Because MYC plays a causal role in many human cancers, including those with hypoxic and nutrient-poor tumor microenvironments, we have determined the metabolic responses of a MYC-inducible human Burkitt lymphoma model P493 cell line to aerobic and hypoxic conditions, and to glucose deprivation, using Stable Isotope Resolved Metabolomics. Using [U-13C]-glucose as the tracer, both glucose consumption and lactate production were increased by MYC expression and hypoxia. Using [U-13C,15N]-glutamine as the tracer, glutamine import and metabolism through the TCA cycle persisted under hypoxia, and glutamine contributed significantly to citrate carbons. Under glucose deprivation, glutamine-derived fumarate, malate, and citrate were significantly increased. Their 13C labeling patterns demonstrate an alternative energy-generating glutaminolysis pathway involving a glucose-independent TCA cycle. The essential role of glutamine metabolism in cell survival and proliferation under hypoxia and glucose deficiency, makes them susceptible to the glutaminase inhibitor BPTES, and hence could be targeted for cancer therapy. PMID:22225880

  18. HSulf-1 deficiency dictates a metabolic reprograming of glycolysis and TCA cycle in ovarian cancer.

    PubMed

    Mondal, Susmita; Roy, Debarshi; Camacho-Pereira, Juliana; Khurana, Ashwani; Chini, Eduardo; Yang, Lifeng; Baddour, Joelle; Stilles, Katherine; Padmabandu, Seth; Leung, Sam; Kalloger, Steve; Gilks, Blake; Lowe, Val; Dierks, Thomas; Hammond, Edward; Dredge, Keith; Nagrath, Deepak; Shridhar, Viji

    2015-10-20

    Warburg effect has emerged as a potential hallmark of many cancers. However, the molecular mechanisms that led to this metabolic state of aerobic glycolysis, particularly in ovarian cancer (OVCA) have not been completely elucidated. HSulf-1 predominantly functions by limiting the bioavailability of heparan binding growth factors and hence their downstream signaling. Here we report that HSulf-1, a known putative tumor suppressor, is a negative regulator of glycolysis. Silencing of HSulf-1 expression in OV202 cell line increased glucose uptake and lactate production by upregulating glycolytic genes such as Glut1, HKII, LDHA, as well as metabolites. Conversely, HSulf-1 overexpression in TOV21G cells resulted in the down regulation of glycolytic enzymes and reduced glycolytic phenotype, supporting the role of HSulf-1 loss in enhanced aerobic glycolysis. HSulf-1 deficiency mediated glycolytic enhancement also resulted in increased inhibitory phosphorylation of pyruvate dehydrogenase (PDH) thus blocking the entry of glucose flux into TCA cycle. Consistent with this, metabolomic and isotope tracer analysis showed reduced glucose flux into TCA cycle. Moreover, HSulf-1 loss is associated with lower oxygen consumption rate (OCR) and impaired mitochondrial function. Mechanistically, lack of HSulf-1 promotes c-Myc induction through HB-EGF-mediated p-ERK activation. Pharmacological inhibition of c-Myc reduced HB-EGF induced glycolytic enzymes implicating a major role of c-Myc in loss of HSulf-1 mediated altered glycolytic pathway in OVCA. Similarly, PG545 treatment, an agent that binds to heparan binding growth factors and sequesters growth factors away from their ligand also blocked HB-EGF signaling and reduced glucose uptake in vivo in HSulf-1 deficient cells. PMID:26378042

  19. The TCA cycle is not required for selection or survival of multidrug-resistant Salmonella

    PubMed Central

    Ricci, Vito; Loman, Nick; Pallen, Mark; Ivens, Alasdair; Fookes, Maria; Langridge, Gemma C.; Wain, John; Piddock, Laura J. V.

    2012-01-01

    Objectives The initial aim of this study was to use a systems biology approach to analyse a ciprofloxacin-selected multidrug-resistant (MDR) Salmonella enterica serotype Typhimurium, L664. Methods The whole genome sequence and transcriptome of L664 were analysed. Site-directed mutagenesis to recreate each mutation was carried out, followed by phenotypic characterization and mutation frequency analysis. As a mutation in the TCA cycle was detected we tested the controversial hypothesis regarding the bacterial response to bactericidal antibiotics, put forward by Kohanski et al. (Cell 2007; 130: 797–810 and Mol Cell 2010; 37: 311–20), that exposure of bacteria to agents such as ciprofloxacin produces reactive oxygen species (ROS), which transiently increase the mutation rate giving rise to MDR bacteria. Results L664 contained a mutation in ramR that conferred MDR. A mutation in tctA affected the TCA cycle and conferred the inability to grow on minimal agar. The virulence of L664 was not attenuated. Ciprofloxacin exposure produced ROS in L664 and SL1344 (tctA::aph), but it was reduced and occurred later. There were no significant differences in the rates of killing or mutations per generation to antibiotic resistance between the strains. Conclusions Whilst we confirm production of ROS in response to ciprofloxacin, we have no data to support the hypothesis that this leads to selection of MDR strains. Our results indicate that the mutations in tctA and glgA were random as they did not pre-exist in the parental strain, and that the mutation in tctA did not provide a survival advantage or disadvantage in the presence of antibiotic. PMID:22186876

  20. Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) mixture toxicity to the macrophytes Myriophyllum spicatum and Myriophyllum sibiricum in aquatic microcosms.

    PubMed

    Hanson, Mark L; Sibley, Paul K; Mabury, Scott A; Solomon, Keith R; Muir, Derek C G

    2002-02-21

    Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) have been detected together in environmental water samples throughout the world. TCA may enter into aquatic systems via rainout as the degradation product of chlorinated solvents, herbicide use, as a by-product of water disinfection and from emissions of spent bleach liquor of kraft pulp mills. Sources of TFA include degradation of hydrofluorocarbons (HFCs) refrigerants and pesticides. These substances are phytotoxic and widely distributed in aquatic environments. A study to assess the risk of a binary mixture of TCA and TFA to macrophytes in aquatic microcosms was conducted as part of a larger study on haloacetic acids. M. spicatum and M. sibiricum were exposed to 0.1, 1, 3 and 10 mg/l of both TCA and TFA (neutralized with sodium hydroxide) in replicate (n = 3) 12000 l aquatic microcosms for 49 days in an one-way analysis of variance design. Each microcosm was stocked with 14 individual apical shoots per species. The plants were sampled at regular intervals and assessed for the somatic endpoints of plant length, root growth, number of nodes and wet and dry mass and the biochemical endpoints of chlorophyll-a, chlorophyll-b, carotenoid content and citric acid levels. Results indicate that there were statistically significant effects of the TCA/TFA mixture on certain pigment concentrations immediately after the start of exposure (2-7 days), but the plants showed no signs of stress thereafter. These data suggest that TCA/TFA mixtures at environmentally relevant concentrations do not pose a significant risk to these aquatic macrophytes. PMID:11878273

  1. The Role of TCA Cycle Anaplerosis in Ketosis and Fatty Liver in Periparturient Dairy Cows.

    PubMed

    White, Heather M

    2015-01-01

    The transition to lactation period in dairy cattle is characterized by metabolic challenges, negative energy balance, and adipose tissue mobilization. Metabolism of mobilized adipose tissue is part of the adaptive response to negative energy balance in dairy cattle; however, the capacity of the liver to completely oxidize nonesterified fatty acids may be limited and is reflective of oxaloacetate pool, the carbon carrier of the tricarboxylic acid cycle. Alternative metabolic fates of acetyl-CoA from nonesterified fatty acids include esterification to triacylglycerides and ketogenesis, and when excessive, these pathways lead to fatty liver and ketosis. Examination of the anaplerotic and cataplerotic pull of oxaloacetate by the tricarboxylic acid cycle and gluconeogenesis may provide insight into the balance of oxidation and esterification of acetyl-CoA within the liver of periparturient dairy cows. PMID:26479386

  2. Increased anaplerosis, TCA cycling, and oxidative phosphorylation in the liver of dairy cows with intensive body fat mobilization during early lactation.

    PubMed

    Schäff, Christine; Börner, Sabina; Hacke, Sandra; Kautzsch, Ulrike; Albrecht, Dirk; Hammon, Harald M; Röntgen, Monika; Kuhla, Björn

    2012-11-01

    The onset of milk production lets mammals experience an enormous energy and nutrient demand. To meet these requirements, high-yielding dairy cows mobilize body fat resulting in an augmented hepatic oxidative metabolism, which has been suggested to signal for depressing hunger after calving. To examine how the extent of fat mobilization influences hepatic oxidative metabolism and thus potentially feed intake, blood and liver samples of 19 Holstein cows were taken throughout the periparturient period. Retrospectively grouped according to high (H) and low (L) liver fat content, H cows showed higher fatty acid but lower amino acid plasma concentrations and lower feed intake than L cows. The hepatic phospho-AMPK/total AMP ratio was not different between groups but decreased after parturition. A 2-DE coupled MALDI-TOF-TOF analysis and qRT-PCR studies revealed H cows having lower expressions of major enzymes involved in mitochondrial β-oxidation, urea cycling, and the pentose phosphate pathway but higher expressions of enzymes participating in peroxisomal and endoplasmic fatty acid degradation, pyruvate and TCA cycling, amino acid catabolism, oxidative phosphorylation, and oxidative stress defense. These data indicate that increasing lipolysis leads to augmenting nutrient catabolism for anaplerosis and mitochondrial respiration, providing a molecular link between hepatic oxidative processes and feed intake. PMID:23046364

  3. Tracer-based assessments of hepatic anaplerotic and TCA cycle flux: practicality, stoichiometry, and hidden assumptions.

    PubMed

    Previs, Stephen F; Kelley, David E

    2015-10-15

    Two groups recently used different tracer methods to quantify liver-specific flux rates. The studies had a similar goal, i.e., to characterize mitochondrial oxidative function. These efforts could have a direct impact on our ability to understand metabolic abnormalities that affect the pathophysiology of fatty liver and allow us to examine mechanisms surrounding potential therapeutic interventions. Briefly, one method couples the continuous infusion of [(13)C]acetate with direct real-time measurements of [(13)C]glutamate labeling in liver; the other method administers [(13)C]propionate, in combination with other tracers, and subsequently measures the (13)C labeling of plasma glucose and/or acetaminophen-glucuronide. It appears that a controversy has arisen, since the respective methods yielded different estimates of the anaplerotic/TCA flux ratio (VANA:VTCA) in "control" subjects, i.e., the [(13)C]acetate- and [(13)C]propionate-derived VANA:VTCA flux ratios appear to be ∼1.4 and ∼5, respectively. While the deep expertise in the respective groups makes it somewhat trivial for each to perform the tracer studies, the data interpretation is inherently difficult. The current perspective was undertaken to examine potential factors that could account for or contribute to the apparent differences. Attention was directed toward 1) matters of practicality, 2) issues surrounding stoichiometry, and 3) hidden assumptions. We believe that the [(13)C]acetate method has certain weaknesses that limit its utility; in contrast, the [(13)C]propionate method likely yields a more correct answer. We hope our discussion will help clarify the differences in the recent reports. Presumably this will be of interest to investigators who are considering tracer-based studies of liver metabolism. PMID:26330343

  4. A Dysfunctional Tricarboxylic Acid Cycle Enhances Fitness of Staphylococcus epidermidis During β-Lactam Stress

    PubMed Central

    Chittezham Thomas, Vinai; Kinkead, Lauren C.; Janssen, Ashley; Schaeffer, Carolyn R.; Woods, Keith M.; Lindgren, Jill K.; Peaster, Jonathan M.; Chaudhari, Sujata S.; Sadykov, Marat; Jones, Joselyn; Mohamadi AbdelGhani, Sameh M.; Zimmerman, Matthew C.; Bayles, Kenneth W.; Somerville, Greg A.; Fey, Paul D.

    2013-01-01

    ABSTRACT A recent controversial hypothesis suggested that the bactericidal action of antibiotics is due to the generation of endogenous reactive oxygen species (ROS), a process requiring the citric acid cycle (tricarboxylic acid [TCA] cycle). To test this hypothesis, we assessed the ability of oxacillin to induce ROS production and cell death in Staphylococcus epidermidis strain 1457 and an isogenic citric acid cycle mutant. Our results confirm a contributory role for TCA-dependent ROS in enhancing susceptibility of S. epidermidis toward β-lactam antibiotics and also revealed a propensity for clinical isolates to accumulate TCA cycle dysfunctions presumably as a way to tolerate these antibiotics. The increased protection from β-lactam antibiotics could result from pleiotropic effects of a dysfunctional TCA cycle, including increased resistance to oxidative stress, reduced susceptibility to autolysis, and a more positively charged cell surface. PMID:23963176

  5. Uncertainty of Prebiotic Scenarios: The Case of the Non-Enzymatic Reverse Tricarboxylic Acid Cycle

    PubMed Central

    Zubarev, Dmitry Yu; Rappoport, Dmitrij; Aspuru-Guzik, Alán

    2015-01-01

    We consider the hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach to quantify the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for investigations of the origin of the common metabolic core should be significantly extended. PMID:25620471

  6. Uncertainty of prebiotic scenarios: the case of the non-enzymatic reverse tricarboxylic acid cycle.

    PubMed

    Zubarev, Dmitry Yu; Rappoport, Dmitrij; Aspuru-Guzik, Alán

    2015-01-01

    We consider the hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach to quantify the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for investigations of the origin of the common metabolic core should be significantly extended. PMID:25620471

  7. Uncertainty of Prebiotic Scenarios: The Case of the Non-Enzymatic Reverse Tricarboxylic Acid Cycle

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry Yu; Rappoport, Dmitrij; Aspuru-Guzik, Alán

    2015-01-01

    We consider the hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach to quantify the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for investigations of the origin of the common metabolic core should be significantly extended.

  8. Integrated, Step-Wise, Mass-Isotopomeric Flux Analysis of the TCA Cycle.

    PubMed

    Alves, Tiago C; Pongratz, Rebecca L; Zhao, Xiaojian; Yarborough, Orlando; Sereda, Sam; Shirihai, Orian; Cline, Gary W; Mason, Graeme; Kibbey, Richard G

    2015-11-01

    Mass isotopomer multi-ordinate spectral analysis (MIMOSA) is a step-wise flux analysis platform to measure discrete glycolytic and mitochondrial metabolic rates. Importantly, direct citrate synthesis rates were obtained by deconvolving the mass spectra generated from [U-(13)C6]-D-glucose labeling for position-specific enrichments of mitochondrial acetyl-CoA, oxaloacetate, and citrate. Comprehensive steady-state and dynamic analyses of key metabolic rates (pyruvate dehydrogenase, β-oxidation, pyruvate carboxylase, isocitrate dehydrogenase, and PEP/pyruvate cycling) were calculated from the position-specific transfer of (13)C from sequential precursors to their products. Important limitations of previous techniques were identified. In INS-1 cells, citrate synthase rates correlated with both insulin secretion and oxygen consumption. Pyruvate carboxylase rates were substantially lower than previously reported but showed the highest fold change in response to glucose stimulation. In conclusion, MIMOSA measures key metabolic rates from the precursor/product position-specific transfer of (13)C-label between metabolites and has broad applicability to any glucose-oxidizing cell. PMID:26411341

  9. Evolution and Functional Implications of the Tricarboxylic Acid Cycle as Revealed by Phylogenetic Analysis

    PubMed Central

    Cavalcanti, João Henrique Frota; Esteves-Ferreira, Alberto A.; Quinhones, Carla G.S.; Pereira-Lima, Italo A.; Nunes-Nesi, Adriano; Fernie, Alisdair R.; Araújo, Wagner L.

    2014-01-01

    The tricarboxylic acid (TCA) cycle, a crucial component of respiratory metabolism, is composed of a set of eight enzymes present in the mitochondrial matrix. However, most of the TCA cycle enzymes are encoded in the nucleus in higher eukaryotes. In addition, evidence has accumulated demonstrating that nuclear genes were acquired from the mitochondrial genome during the course of evolution. For this reason, we here analyzed the evolutionary history of all TCA cycle enzymes in attempt to better understand the origin of these nuclear-encoded proteins. Our results indicate that prior to endosymbiotic events the TCA cycle seemed to operate only as isolated steps in both the host (eubacterial cell) and mitochondria (alphaproteobacteria). The origin of isoforms present in different cell compartments might be associated either with gene-transfer events which did not result in proper targeting of the protein to mitochondrion or with duplication events. Further in silico analyses allow us to suggest new insights into the possible roles of TCA cycle enzymes in different tissues. Finally, we performed coexpression analysis using mitochondrial TCA cycle genes revealing close connections among these genes most likely related to the higher efficiency of oxidative phosphorylation in this specialized organelle. Moreover, these analyses allowed us to identify further candidate genes which might be used for metabolic engineering purposes given the importance of the TCA cycle during development and/or stress situations. PMID:25274566

  10. Combined effects of CO2 enrichment and elevated growth temperatures on metabolites in soybean leaflets: evidence for dynamic changes of TCA cycle intermediates.

    PubMed

    Sicher, Richard

    2013-08-01

    Soybean (Glycine max [Merr.] L.) was grown in indoor chambers with ambient (38 Pa) and elevated (70 Pa) CO2 and day/night temperature treatments of 28/20, 32/24 and 36/28 °C. We hypothesized that CO2 enrichment would mitigate the deleterious effects of elevated growth temperatures on metabolites in soybean leaflets. Net CO2 assimilation rates increased incrementally with growth temperature and were enhanced up to 24 % on average by CO2 enrichment. Stomatal conductance about doubled from the lowest to highest temperature but this was partially reversed by CO2 enrichment. Metabolites were measured thrice daily and 19 and 28 of 43 total leaf metabolites were altered by the 32/24 and 36/28 °C temperature treatments, respectively, in both CO2 treatments. Polyols, raffinose and GABA increased and 23 nonstructural carbohydrates, organic acids and amino acids decreased when the temperature was increased from 28 to 36 °C under ambient CO2. Citrate, aconitate and 2-oxoglutarate decreased over 90 % in the 36/28 °C compared to the 28/20 °C temperature treatment. Temperature-dependent changes of sugars, organic acids and all but three amino acids were almost completely eliminated by CO2 enrichment. The above findings suggested that specific TCA cycle intermediates were highly depleted by heat stress under ambient CO2. Mitigating effects of CO2 enrichment on soybean leaflet metabolites were attributed to altered rates of photosynthesis, photorespiration, dark respiration, the anaplerotic pathway and to possible changes of gene expression. PMID:23716183

  11. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

    PubMed Central

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

  12. TCA cycle activity in Staphylococcus aureus is essential for iron-regulated synthesis of staphyloferrin A, but not staphyloferrin B: the benefit of a second citrate synthase.

    PubMed

    Sheldon, Jessica R; Marolda, Cristina L; Heinrichs, David E

    2014-05-01

    Staphylococcus aureus elaborates two citrate-containing siderophores, staphyloferrin A (SA) and staphyloferrin B (SB), that enhance growth under iron-restriction, yet, paradoxically, expression of the TCA cycle citrate synthase, CitZ, is downregulated during iron starvation. Iron starvation does, however, result in expression of SbnG, recently identified as a novel citrate synthase that is encoded from within the iron-regulated SB biosynthetic locus, suggesting an important role for SbnG in staphyloferrin production. We demonstrate that during growth of S. aureus in iron-restricted media containing glucose, SB is produced but, in contrast, SA production is severely repressed; accordingly, SB-deficient mutants grow poorly in these media. Hypothesizing that reduced TCA cycle activity hinders SA production, we show that a citZ mutant is capable of SB synthesis, but not SA synthesis, providing evidence that SbnG does not generate citrate for incorporation into SA. A citZ sbnG mutant synthesizes neither staphyloferrin, is severely compromised for growth in iron-restricted media, and is significantly more impaired for virulence than either of the single-deletion mutants. We propose that SB is the more important of the two siderophores for S. aureus insofar as it is synthesized, and supports iron-restricted growth, without need of TCA cycle activity. PMID:24666349

  13. Simultaneous determination of tricarboxylic acid cycle metabolites by high-performance liquid chromatography with ultraviolet detection.

    PubMed

    Shurubor, Yevgeniya I; Cooper, Arthur J L; Isakova, Elena P; Deryabina, Yulia I; Beal, M Flint; Krasnikov, Boris F

    2016-06-15

    Here we describe a simple high-performance liquid chromatography (HPLC) procedure for the simultaneous detection and quantitation in standard solutions of 13 important metabolites of cellular energy metabolism, including 9 tricarboxylic acid (TCA) cycle components and 4 additional metabolites. The metabolites are detected by their absorbance at 210 nm. The procedure does not require prior derivatization, and an analysis can be carried out at ambient temperature within 15 min. The significance of the current work is that the current HPLC procedure should motivate the development of simplified TCA cycle enzyme assays, isotopomer analysis, and determination of selected TCA metabolite levels in plasma/tissues. PMID:27001310

  14. The Effect of Walterinnesia aegyptia Venom Proteins on TCA Cycle Activity and Mitochondrial NAD+-Redox State in Cultured Human Fibroblasts

    PubMed Central

    Ghneim, Hazem K.; Al-Sheikh, Yazeed A.; Aboul-Soud, Mourad A. M.

    2015-01-01

    Fibroblast cultures were used to study the effects of crude Walterinnesia aegyptia venom and its F1–F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP+-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50–60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60–70% for fractions F3 and F6. In addition, the crude and fractions F3–F7 venom proteins caused a drop in mitochondrial NAD+ and NADP+ levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60–70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD+ and NADP+ biosynthesis. PMID:25705684

  15. The effect of Walterinnesia aegyptia venom proteins on TCA cycle activity and mitochondrial NAD(+)-redox state in cultured human fibroblasts.

    PubMed

    Ghneim, Hazem K; Al-Sheikh, Yazeed A; Aboul-Soud, Mourad A M

    2015-01-01

    Fibroblast cultures were used to study the effects of crude Walterinnesia aegyptia venom and its F1-F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP(+)-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50-60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60-70% for fractions F3 and F6. In addition, the crude and fractions F3-F7 venom proteins caused a drop in mitochondrial NAD(+) and NADP(+) levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60-70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD(+) and NADP(+) biosynthesis. PMID:25705684

  16. The Majority of Free-Living Autotrophic Bacteria use the Reductive TCA Cycle for Carbon Fixation at Deep-Sea Hydrothermal Vents

    NASA Astrophysics Data System (ADS)

    Campbell, B. J.; Cary, C.

    2003-12-01

    Deep-sea hydrothermal vents support large micro and macroscopic communities, without the input of photosynthesis. Autotrophic production at these vents is based on hydrothermal vent fluid chemistry. Primary production has been thought to occur mainly via hydrogen sulfide oxidation through the Calvin-Benson pathway, as measured by the presence of Rubisco in endosymbionts of several invertebrate hosts. Recently, we characterized two fosmids from a large insert library of the epsilon Proteobacterial episymbionts of Alvinella pompejana. Both contained sequences encoding ATP citrate lyase, a key enzyme in the reverse TCA cycle, an alternate carbon dioxide fixation pathway. Previous investigators have demonstrated the dominance of the epsilon subdivision in the free-living bacterial communities at hydrothermal vents. Based on these results, our working hypothesis is: The rTCA cycle is the dominant pathway for carbon fixation in the free-living bacterial communities at hydrothermal vents. A selection of free-living bacterial communities from various geographic locations (9N, East Pacific Rise and Guaymas Basin) were screened for the presence, diversity and expression (via RT-PCR) of Rubisco (forms I and II) and ATP citrate lyase. Our results indicate that the ATP citrate lyase gene is diverse and is consistently expressed in several types of vent communities. The two forms of Rubisco are not consistently present or expressed in the same environments. These results indicate that chemoautotrophic production in the free-living bacterial communities at deep-sea hydrothermal vents is dominated by bacteria that utilize the rTCA cycle, and parallels the phylogenetic dominance of members of the epsilon subdivision of Proteobacteria.

  17. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity.

    PubMed

    Patterson, Rainey E; Kalavalapalli, Srilaxmi; Williams, Caroline M; Nautiyal, Manisha; Mathew, Justin T; Martinez, Janie; Reinhard, Mary K; McDougall, Danielle J; Rocca, James R; Yost, Richard A; Cusi, Kenneth; Garrett, Timothy J; Sunny, Nishanth E

    2016-04-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH. PMID:26814015

  18. The Pyruvate-Tricarboxylic Acid Cycle Node

    PubMed Central

    Bücker, René; Heroven, Ann Kathrin; Becker, Judith; Dersch, Petra; Wittmann, Christoph

    2014-01-01

    Despite our increasing knowledge of the specific pathogenicity factors in bacteria, the contribution of metabolic processes to virulence is largely unknown. Here, we elucidate a tight connection between pathogenicity and core metabolism in the enteric pathogen Yersinia pseudotuberculosis by integrated transcriptome and [13C]fluxome analysis of the wild type and virulence-regulator mutants. During aerobic growth on glucose, Y. pseudotuberculosis reveals an unusual flux distribution with a high level of secreted pyruvate. The absence of the transcriptional and post-transcriptional regulators RovA, CsrA, and Crp strongly perturbs the fluxes of carbon core metabolism at the level of pyruvate metabolism and the tricarboxylic acid (TCA) cycle, and these perturbations are accompanied by transcriptional changes in the corresponding enzymes. Knock-outs of regulators of this metabolic branch point and of its central enzyme, pyruvate kinase (ΔpykF), result in mutants with significantly reduced virulence in an oral mouse infection model. In summary, our work identifies the pyruvate-TCA cycle node as a focal point for controlling the host colonization and virulence of Yersinia. PMID:25164818

  19. Metabolic engineering in the biotechnological production of organic acids in the tricarboxylic acid cycle of microorganisms: Advances and prospects.

    PubMed

    Yin, Xian; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Liu, Long; Chen, Jian

    2015-11-01

    Organic acids, which are chemically synthesized, are also natural intermediates in the metabolic pathways of microorganisms, among which the tricarboxylic acid (TCA) cycle is the most crucial route existing in almost all living organisms. Organic acids in the TCA cycle include citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, l-malic acid, and oxaloacetate, which are building-block chemicals with wide applications and huge markets. In this review, we summarize the synthesis pathways of these organic acids and review recent advances in metabolic engineering strategies that enhance organic acid production. We also propose further improvements for the production of organic acids with systems and synthetic biology-guided metabolic engineering strategies. PMID:25902192

  20. Uncertainty of Prebiotic Scenarios: The Case of the Non-Enzymatic Reverse Tricarboxylic Acid Cycle

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry; Rappoport, Dmitrij; Aspuru-Guzik, Alan

    2015-03-01

    We consider the much discussed hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach that quantifies the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for the investigations of the origin of the common metabolic core should be significantly extended. This work was supported by a grant from the Simons Foundation (SCOL 291937, Dmitry Zubarev).

  1. The tricarboxylic acid cycle in Shewanella oneidensis is independent of Fur and RyhB control

    SciTech Connect

    Yang, Yunfeng; McCue, Lee Ann; Parsons, Andrea; Feng, Sheng; Zhou, Jizhong

    2010-01-01

    Background: It is well established in E. coli and Vibrio cholerae that strains harboring mutations in the ferric uptake regulator gene (fur) are unable to utilize tricarboxylic acid (TCA) compounds, due to the down-regulation of key TCA cycle enzymes, such as AcnA and SdhABCD. This down-regulation is mediated by a Fur-regulated small regulatory RNA named RyhB. It is unclear in the g-proteobacterium S. oneidensis whether TCA is also regulated by Fur and RyhB. Results: In the present study, we showed that a fur deletion mutant of S. oneidensis could utilize TCA compounds. Consistently, expression of the TCA cycle genes acnA and sdhA was not down-regulated in the mutant. To explore this observation further, we identified a ryhB gene in Shewanella species and experimentally demonstrated the gene expression. Further experiments suggested that RyhB was up-regulated in fur mutant, but that AcnA and SdhA were not controlled by RyhB. Conclusions: These cumulative results delineate an important difference of the Fur-RyhB regulatory cycle between S. oneidensis and other g-proteobacteria. This work represents a step forward for understanding the unique regulation in S. oneidensis.

  2. An ATP and oxalate generating variant tricarboxylic acid cycle counters aluminum toxicity in Pseudomonas fluorescens.

    PubMed

    Singh, Ranji; Lemire, Joseph; Mailloux, Ryan J; Chénier, Daniel; Hamel, Robert; Appanna, Vasu D

    2009-01-01

    Although the tricarboxylic acid (TCA) cycle is essential in almost all aerobic organisms, its precise modulation and integration in global cellular metabolism is not fully understood. Here, we report on an alternative TCA cycle uniquely aimed at generating ATP and oxalate, two metabolites critical for the survival of Pseudomonas fluorescens. The upregulation of isocitrate lyase (ICL) and acylating glyoxylate dehydrogenase (AGODH) led to the enhanced synthesis of oxalate, a dicarboxylic acid involved in the immobilization of aluminum (Al). The increased activity of succinyl-CoA synthetase (SCS) and oxalate CoA-transferase (OCT) in the Al-stressed cells afforded an effective route to ATP synthesis from oxalyl-CoA via substrate level phosphorylation. This modified TCA cycle with diminished efficacy in NADH production and decreased CO(2)-evolving capacity, orchestrates the synthesis of oxalate, NADPH, and ATP, ingredients pivotal to the survival of P. fluorescens in an Al environment. The channeling of succinyl-CoA towards ATP formation may be an important function of the TCA cycle during anaerobiosis, Fe starvation and O(2)-limited conditions. PMID:19809498

  3. Tricarboxylic acid cycle intermediate pool size: functional importance for oxidative metabolism in exercising human skeletal muscle.

    PubMed

    Bowtell, Joanna L; Marwood, Simon; Bruce, Mark; Constantin-Teodosiu, Dumitru; Greenhaff, Paul L

    2007-01-01

    The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool

  4. Regulation of leukocyte tricarboxylic acid cycle in drug-naïve Bipolar Disorder.

    PubMed

    de Sousa, Rafael T; Streck, Emilio L; Forlenza, Orestes V; Brunoni, Andre R; Zanetti, Marcus V; Ferreira, Gabriela K; Diniz, Breno S; Portela, Luis V; Carvalho, André F; Zarate, Carlos A; Gattaz, Wagner F; Machado-Vieira, Rodrigo

    2015-09-25

    Several lines of evidence suggest a role for mitochondrial dysfunction in the pathophysiology of bipolar disorder (BD). The tricarboxylic acid cycle (TCA cycle) is fundamental for mitochondrial energy production and produces substrates used in oxidative phosphorylation by the mitochondrial electron transport chain. The activity of the key TCA cycle enzymes citrate synthase, malate dehydrogenase, and succinate dehydrogenase has never been evaluated in BD. In the present study, these enzymes were assayed from leukocytes of drug-naïve BD patients in a major depressive episode (n=18) and compared to 24 age-matched healthy controls. Drug-naïve BD patients did not show differences in activities of citrate synthase (p=0.79), malate dehydrogenase (p=0.17), and succinate dehydrogenase (p=0.35) compared with healthy controls. No correlation between any TCA cycle enzyme activity and severity of depressive symptoms was observed. Overall, these data suggest that the activities of the TCA cycle enzymes are not altered in major depressive episodes of recent-onset BD, which may support the concept of illness staging and neuroprogression in BD. PMID:26297865

  5. Physical interactions between tricarboxylic acid cycle enzymes in Bacillus subtilis: evidence for a metabolon.

    PubMed

    Meyer, Frederik M; Gerwig, Jan; Hammer, Elke; Herzberg, Christina; Commichau, Fabian M; Völker, Uwe; Stülke, Jörg

    2011-01-01

    The majority of all proteins of a living cell is active in complexes rather than in an isolated way. These protein-protein interactions are of high relevance for many biological functions. In addition to many well established protein complexes an increasing number of protein-protein interactions, which form rather transient complexes has recently been discovered. The formation of such complexes seems to be a common feature especially for metabolic pathways. In the Gram-positive model organism Bacillus subtilis, we identified a protein complex of three citric acid cycle enzymes. This complex consists of the citrate synthase, the isocitrate dehydrogenase, and the malate dehydrogenase. Moreover, fumarase and aconitase interact with malate dehydrogenase and with each other. These five enzymes catalyze sequential reaction of the TCA cycle. Thus, this interaction might be important for a direct transfer of intermediates of the TCA cycle and thus for elevated metabolic fluxes via substrate channeling. In addition, we discovered a link between the TCA cycle and gluconeogenesis through a flexible interaction of two proteins: the association between the malate dehydrogenase and phosphoenolpyruvate carboxykinase is directly controlled by the metabolic flux. The phosphoenolpyruvate carboxykinase links the TCA cycle with gluconeogenesis and is essential for B. subtilis growing on gluconeogenic carbon sources. Only under gluconeogenic growth conditions an interaction of these two proteins is detectable and disappears under glycolytic growth conditions. PMID:20933603

  6. In folio respiratory fluxomics revealed by 13C isotopic labeling and H/D isotope effects highlight the noncyclic nature of the tricarboxylic acid "cycle" in illuminated leaves.

    PubMed

    Tcherkez, Guillaume; Mahé, Aline; Gauthier, Paul; Mauve, Caroline; Gout, Elizabeth; Bligny, Richard; Cornic, Gabriel; Hodges, Michael

    2009-10-01

    While the possible importance of the tricarboxylic acid (TCA) cycle reactions for leaf photosynthesis operation has been recognized, many uncertainties remain on whether TCA cycle biochemistry is similar in the light compared with the dark. It is widely accepted that leaf day respiration and the metabolic commitment to TCA decarboxylation are down-regulated in illuminated leaves. However, the metabolic basis (i.e. the limiting steps involved in such a down-regulation) is not well known. Here, we investigated the in vivo metabolic fluxes of individual reactions of the TCA cycle by developing two isotopic methods, (13)C tracing and fluxomics and the use of H/D isotope effects, with Xanthium strumarium leaves. We provide evidence that the TCA "cycle" does not work in the forward direction like a proper cycle but, rather, operates in both the reverse and forward directions to produce fumarate and glutamate, respectively. Such a functional division of the cycle plausibly reflects the compromise between two contrasted forces: (1) the feedback inhibition by NADH and ATP on TCA enzymes in the light, and (2) the need to provide pH-buffering organic acids and carbon skeletons for nitrate absorption and assimilation. PMID:19675152

  7. Thioredoxin, a master regulator of the tricarboxylic acid cycle in plant mitochondria

    PubMed Central

    Daloso, Danilo M.; Müller, Karolin; Obata, Toshihiro; Florian, Alexandra; Tohge, Takayuki; Bottcher, Alexandra; Riondet, Christophe; Bariat, Laetitia; Carrari, Fernando; Nunes-Nesi, Adriano; Buchanan, Bob B.; Reichheld, Jean-Philippe; Araújo, Wagner L.; Fernie, Alisdair R.

    2015-01-01

    Plant mitochondria have a fully operational tricarboxylic acid (TCA) cycle that plays a central role in generating ATP and providing carbon skeletons for a range of biosynthetic processes in both heterotrophic and photosynthetic tissues. The cycle enzyme-encoding genes have been well characterized in terms of transcriptional and effector-mediated regulation and have also been subjected to reverse genetic analysis. However, despite this wealth of attention, a central question remains unanswered: “What regulates flux through this pathway in vivo?” Previous proteomic experiments with Arabidopsis discussed below have revealed that a number of mitochondrial enzymes, including members of the TCA cycle and affiliated pathways, harbor thioredoxin (TRX)-binding sites and are potentially redox-regulated. We have followed up on this possibility and found TRX to be a redox-sensitive mediator of TCA cycle flux. In this investigation, we first characterized, at the enzyme and metabolite levels, mutants of the mitochondrial TRX pathway in Arabidopsis: the NADP-TRX reductase a and b double mutant (ntra ntrb) and the mitochondrially located thioredoxin o1 (trxo1) mutant. These studies were followed by a comparative evaluation of the redistribution of isotopes when 13C-glucose, 13C-malate, or 13C-pyruvate was provided as a substrate to leaves of mutant or WT plants. In a complementary approach, we evaluated the in vitro activities of a range of TCA cycle and associated enzymes under varying redox states. The combined dataset suggests that TRX may deactivate both mitochondrial succinate dehydrogenase and fumarase and activate the cytosolic ATP-citrate lyase in vivo, acting as a direct regulator of carbon flow through the TCA cycle and providing a mechanism for the coordination of cellular function. PMID:25646482

  8. Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure.

    PubMed

    Dickey, C A; Heal, K V; Stidson, R T; Koren, R; Schröder, P; Cape, J N; Heal, M R

    2004-07-01

    Trichloroacetic acid (TCA, CCl(3)COOH) has been associated with forest damage but the source of TCA to trees is poorly characterised. To investigate the routes and effects of TCA uptake in conifers, 120 Sitka spruce (Picea sitchensis (Bong.) Carr) saplings were exposed to control, 10 or 100 microg l(-1) solutions of TCA applied twice weekly to foliage only or soil only over two consecutive 5-month growing seasons. At the end of each growing season similar elevated TCA concentrations (approximate range 200-300 ng g(-1) dwt) were detected in both foliage and soil-dosed saplings exposed to 100 microg l(-1) TCA solutions showing that TCA uptake can occur from both exposure routes. Higher TCA concentrations in branchwood of foliage-dosed saplings suggest that atmospheric TCA in solution is taken up indirectly into conifer needles via branch and stemwood. TCA concentrations in needles declined slowly by only 25-30% over 6 months of winter without dosing. No effect of TCA exposure on sapling growth was measured during the experiment. However at the end of the first growing season needles of saplings exposed to 10 or 100 microg l(-1) foliage-applied TCA showed significantly more visible damage, higher activities of some detoxifying enzymes, lower protein contents and poorer water control than needles of saplings dosed with the same TCA concentrations to the soil. At the end of each growing season the combined TCA storage in needles, stemwood, branchwood and soil of each sapling was <6% of TCA applied. Even with an estimated half-life of tens of days for within-sapling elimination of TCA during the growing season, this indicates that TCA is eliminated rapidly before uptake or accumulates in another compartment. Although TCA stored in sapling needles accounted for only a small proportion of TCA stored in the sapling/soil system it appears to significantly affect some measures of sapling health. PMID:15158031

  9. The tricarboxylic acid cycle in Shewanella oneidensis is independent of Fur and RyhB control

    SciTech Connect

    Yang, Yunfeng; McCue, Lee Ann; Parsons, Andrea B.; Feng, Sheng; Zhou, Jizhong

    2010-10-26

    It is well established in E. coli and Vibrio cholerae that strains harboring mutations in the ferric uptake regulator gene (fur) are unable to utilize tricarboxylic acid (TCA) compounds, due to the down-regulation of key TCA cycle enzymes, such as AcnA and SdhABCD. This down-regulation is mediated by a Fur-regulated small regulatory RNA named RyhB. In this study, we showed that a fur deletion mutant of the γ-proteobacterium S. oneidensis could utilize TCA compounds. In addition, expression of the TCA cycle genes acnA and sdhA was not down-regulated in the mutant. To explore this observation further, we identified a ryhB gene in Shewanella species and demonstrated its expression experimentally. Further experiments suggested that RyhB was up-regulated in fur mutant, but that AcnA and SdhA were not controlled by RyhB. This work delineates an important difference of the Fur-RyhB regulatory cycle between S. oneidensis and other γ-proteobacteria.

  10. The TCA Pathway is an Important Player in the Regulatory Network Governing Vibrio alginolyticus Adhesion Under Adversity

    PubMed Central

    Huang, Lixing; Huang, Li; Yan, Qingpi; Qin, Yingxue; Ma, Ying; Lin, Mao; Xu, Xiaojin; Zheng, Jiang

    2016-01-01

    Adhesion is a critical step in the initial stage of Vibrio alginolyticus infection; therefore, it is important to understand the underlying mechanisms governing the adhesion of V. alginolyticus and determine if environmental factors have any effect. A greater understanding of this process may assist in developing preventive measures for reducing infection. In our previous research, we presented the first RNA-seq data from V. alginolyticus cultured under stress conditions that resulted in reduced adhesion. Based on the RNA-seq data, we found that the Tricarboxylic acid cycle (TCA pathway) might be closely related to adhesion. Environmental interactions with the TCA pathway might alter adhesion. To validate this, bioinformatics analysis, quantitative Real-Time PCR (qPCR), RNAi, and in vitro adhesion assays were performed, while V. alginolyticus was treated with various stresses including temperature, pH, salinity, and starvation. The expression of genes involved in the TCA pathway was confirmed by qPCR, which reinforced the reliability of the sequencing data. Silencing of these genes was capable of reducing the adhesion ability of V. alginolyticus. Adhesion of V. alginolyticus is influenced substantially by environmental factors and the TCA pathway is sensitive to some environmental stresses, especially changes in pH and starvation. Our results indicated that (1) the TCA pathway plays a key role in V. alginolyticus adhesion: (2) the TCA pathway is sensitive to environmental stresses. PMID:26870007

  11. Efficacy of Modified Jessner's Peel and 20% TCA Versus 20% TCA Peel Alone for the Treatment of Acne Scars

    PubMed Central

    Puri, Neerja

    2015-01-01

    Introduction: There is a paucity of studies on the use of chemical peels for acne scars among the Asian population. A trichloroacetic acid (TCA) and Jessner's combination chemical peel, originally described by Monheit, is said to be better than a TCA peel alone. Aims: The aim of the study was to compare the efficacy of 20% TCA and Jessner's solution versus 20% TCA alone for the treatment of acne scars. Materials and Methods : The patients were divided into two groups of 25 patients each. Chemical peeling was done in both the groups. In Group I, chemical peeling with Jessner's peel followed by 20% TCA was done and in Group II patients chemical peeling with 20% TCA peel alone was done. Results: In Group I (Jessner's peel and 20% TCA), mild improvement of acne scars was seen in 8% cases, moderate improvement in 32% cases and marked improvement of acne scars was seen in 60% patients. In Group II (20% TCA), mild improvement of acne scars was seen in 32% cases, moderate improvement in 40% cases and marked improvement of acne scars was seen in 28% patients. But, the difference in improvement of acne scars was not statistically significant in both the groups (P value > 0.05). PMID:25949022

  12. rre37 Overexpression Alters Gene Expression Related to the Tricarboxylic Acid Cycle and Pyruvate Metabolism in Synechocystis sp. PCC 6803

    PubMed Central

    Iijima, Hiroko; Watanabe, Atsuko; Takanobu, Junko; Hirai, Masami Yokota; Osanai, Takashi

    2014-01-01

    The tricarboxylic acid (TCA) cycle and pyruvate metabolism of cyanobacteria are unique and important from the perspectives of biology and biotechnology research. Rre37, a response regulator induced by nitrogen depletion, activates gene expression related to sugar catabolism. Our previous microarray analysis has suggested that Rre37 controls the transcription of genes involved in sugar catabolism, pyruvate metabolism, and the TCA cycle. In this study, quantitative real-time PCR was used to measure the transcript levels of 12 TCA cycle genes and 13 pyruvate metabolism genes. The transcripts of 6 genes (acnB, icd, ppc, pyk1, me, and pta) increased after 4 h of nitrogen depletion in the wild-type GT strain but the induction was abolished by rre37 overexpression. The repression of gene expression of fumC, ddh, and ackA caused by nitrogen depletion was abolished by rre37 overexpression. The expression of me was differently affected by rre37 overexpression, compared to the other 24 genes. These results indicate that Rre37 differently controls the genes of the TCA cycle and pyruvate metabolism, implying the key reaction of the primary in this unicellular cyanobacterium. PMID:25614900

  13. Triheptanoin partially restores levels of tricarboxylic acid cycle intermediates in the mouse pilocarpine model of epilepsy.

    PubMed

    Hadera, Mussie G; Smeland, Olav B; McDonald, Tanya S; Tan, Kah Ni; Sonnewald, Ursula; Borges, Karin

    2014-04-01

    Triheptanoin, the triglyceride of heptanoate, is anticonvulsant in various epilepsy models. It is thought to improve energy metabolism in the epileptic brain by re-filling the tricarboxylic acid (TCA) cycle with C4-intermediates (anaplerosis). Here, we injected mice with [1,2-(13) C]glucose 3.5-4 weeks after pilocarpine-induced status epilepticus (SE) fed either a control or triheptanoin diet. Amounts of metabolites and incorporations of (13) C were determined in extracts of cerebral cortices and hippocampal formation and enzyme activity and mRNA expression were quantified. The percentage enrichment with two (13) C atoms in malate, citrate, succinate, and GABA was reduced in hippocampal formation of control-fed SE compared with control mice. Except for succinate, these reductions were not found in triheptanoin-fed SE mice, indicating that triheptanoin prevented a decrease of TCA cycle capacity. Compared to those on control diet, triheptanoin-fed SE mice showed few changes in most other metabolite levels and their (13) C labeling. Reduced pyruvate carboxylase mRNA and enzyme activity in forebrains and decreased [2,3-(13) C]aspartate amounts in cortex suggest a pyruvate carboxylation independent source of C-4 TCA cycle intermediates. Most likely anaplerosis was kept unchanged by carboxylation of propionyl-CoA derived from heptanoate. Further studies are proposed to fully understand triheptanoin's effects on neuroglial metabolism and interaction. PMID:24236946

  14. Glutamate is the major anaplerotic substrate in the tricarboxylic acid cycle of isolated rumen epithelial and duodenal mucosal cells from beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study aimed to determine the contribution of substrates to tricarboxylic acid (TCA) cycle fluxes in rumen epithelial (REC) and duodenal mucosal (DMC) cells isolated from bulls (n = 6) fed either a 75% forage (HF) or 75% concentrate (HC) diet. In separate incubations, [13C6]glucose, [13C5]glutam...

  15. Ames Optimized TCA Configuration

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Reuther, James J.; Hicks, Raymond M.

    1999-01-01

    Configuration design at Ames was carried out with the SYN87-SB (single block) Euler code using a 193 x 49 x 65 C-H grid. The Euler solver is coupled to the constrained (NPSOL) and the unconstrained (QNMDIF) optimization packages. Since the single block grid is able to model only wing-body configurations, the nacelle/diverter effects were included in the optimization process by SYN87's option to superimpose the nacelle/diverter interference pressures on the wing. These interference pressures were calculated using the AIRPLANE code. AIRPLANE is an Euler solver that uses a unstructured tetrahedral mesh and is capable of computations about arbitrary complete configurations. In addition, the buoyancy effects of the nacelle/diverters were also included in the design process by imposing the pressure field obtained during the design process onto the triangulated surfaces of the nacelle/diverter mesh generated by AIRPLANE. The interference pressures and nacelle buoyancy effects are added to the final forces after each flow field calculation. Full details of the (recently enhanced) ghost nacelle capability are given in a related talk. The pseudo nacelle corrections were greatly improved during this design cycle. During the Ref H and Cycle 1 design activities, the nacelles were only translated and pitched. In the cycle 2 design effort the nacelles can translate vertically, and pitch to accommodate the changes in the lower surface geometry. The diverter heights (between their leading and trailing edges) were modified during design as the shape of the lower wing changed, with the drag of the diverter changing accordingly. Both adjoint and finite difference gradients were used during optimization. The adjoint-based gradients were found to give good direction in the design space for configurations near the starting point, but as the design approached a minimum, the finite difference gradients were found to be more accurate. Use of finite difference gradients was limited by the

  16. Catabolite Control Protein E (CcpE) Is a LysR-type Transcriptional Regulator of Tricarboxylic Acid Cycle Activity in Staphylococcus aureus*

    PubMed Central

    Hartmann, Torsten; Zhang, Bo; Baronian, Grégory; Schulthess, Bettina; Homerova, Dagmar; Grubmüller, Stephanie; Kutzner, Erika; Gaupp, Rosmarie; Bertram, Ralph; Powers, Robert; Eisenreich, Wolfgang; Kormanec, Jan; Herrmann, Mathias; Molle, Virginie; Somerville, Greg A.; Bischoff, Markus

    2013-01-01

    The tricarboxylic acid cycle (TCA cycle) is a central metabolic pathway that provides energy, reducing potential, and biosynthetic intermediates. In Staphylococcus aureus, TCA cycle activity is controlled by several regulators (e.g. CcpA, CodY, and RpiRc) in response to the availability of sugars, amino acids, and environmental stress. Developing a bioinformatic search for additional carbon catabolite-responsive regulators in S. aureus, we identified a LysR-type regulator, catabolite control protein E (CcpE), with homology to the Bacillus subtilis CcpC regulator. Inactivation of ccpE in S. aureus strain Newman revealed that CcpE is a positive transcriptional effector of the first two enzymes of the TCA cycle, aconitase (citB) and to a lesser extent citrate synthase (citZ). Consistent with the transcriptional data, aconitase activity dramatically decreased in the ccpE mutant relative to the wild-type strain. The effect of ccpE inactivation on citB transcription and the lesser effect on citZ transcription were also reflected in electrophoretic mobility shift assays where CcpE bound to the citB promoter but not the citZ promoter. Metabolomic studies showed that inactivation of ccpE resulted in increased intracellular concentrations of acetate, citrate, lactate, and alanine, consistent with a redirection of carbon away from the TCA cycle. Taken together, our data suggest that CcpE is a major direct positive regulator of the TCA cycle gene citB. PMID:24194525

  17. Modulation of fatty acid metabolism and tricarboxylic acid cycle to enhance the lipstatin production through medium engineering in Streptomyces toxytricini.

    PubMed

    Kumar, Punit; Dubey, Kashyap Kumar

    2016-08-01

    This work investigated the potential of medium engineering to obtain maximum biomass, non-conventional carbon sources for lipstatin production and modulation of tricarboxylic acid (TCA) cycle to promote lipstatin synthesis. It was found that 2:3 carbon and nitrogen ratio, produced maximum biomass of 7.9g/L in growth medium and 6.6g/L in pre-seed medium. Among the studied non-conventional carbon sources i.e., soya flour 40g/L and sesame oil 30mL/L were found producing 1109.37mg/L (1.24-fold of control) and 1196.75mg/L (1.34-fold of control) lipstatin respectively. Supplementation of TCA cycle intermediates revealed that NADH and succinic acid showed lipstatin production to 1132.99mg/L and 1171.10mg/L respectively. Experimental outcome was validated in 7L bioreactor and produced 2242.63mg/L lipstatin which was ∼14% higher than shake flask. PMID:26897471

  18. Viscous Design of TCA Configuration

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Campbell, Richard L.

    1999-01-01

    The goal in this effort is to redesign the baseline TCA configuration for improved performance at both supersonic and transonic cruise. Viscous analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between overset grids. Viscous designs are conducted with OVERDISC, a script which couples OVERFLOW with the Constrained Direct Iterative Surface Curvature (CDISC) inverse design method. The successful execution of any computational fluid dynamics (CFD) based aerodynamic design method for complex configurations requires an efficient method for regenerating the computational grids to account for modifications to the configuration shape. The first section of this presentation deals with the automated regridding procedure used to generate overset grids for the fuselage/wing/diverter/nacelle configurations analysed in this effort. The second section outlines the procedures utilized to conduct OVERDISC inverse designs. The third section briefly covers the work conducted by Dick Campbell, in which a dual-point design at Mach 2.4 and 0.9 was attempted using OVERDISC; the initial configuration from which this design effort was started is an early version of the optimized shape for the TCA configuration developed by the Boeing Commercial Airplane Group (BCAG), which eventually evolved into the NCV design. The final section presents results from application of the Natural Flow Wing design philosophy to the TCA configuration.

  19. Prebiotic Metabolism: Production by Mineral Photoelectrochemistry of α-Ketocarboxylic Acids in the Reductive Tricarboxylic Acid Cycle

    NASA Astrophysics Data System (ADS)

    Guzman, Marcelo I.; Martin, Scot T.

    2009-11-01

    A reductive tricarboxylic acid (rTCA) cycle could have fixed carbon dioxide as bio chemically useful energy-storage molecules on early Earth. Nonenzymatic chemical pathways for some steps of the rTCA cycle, however, such as the production of the α-ketocarboxylic acids pyruvate and α-ketoglutarate, remain a challenging problem for the viability of the proposed prebiotic cycle. As a class of compounds, α-ketocarboxylic acids have high free energies of formation that disfavor their production. We report herein the production of pyruvate from lactate and of α-ketoglutarate from pyruvate in the millimolar concentration range as promoted by ZnS mineral photoelectrochemistry. Pyruvate is produced from the photooxidation of lactate with 70% yield and a quantum efficiency of 0.009 at 15°C across the wavelength range of 200-400 nm. The produced pyruvate undergoes photoreductive back reaction to lactate at a 30% yield and with a quantum efficiency of 0.0024. Pyruvate alternatively continues in photooxidative forward reaction to α-ketoglutarate with a 50% yield and a quantum efficiency of 0.0036. The remaining 20% of the carbon follows side reactions that produce isocitrate, glutarate, and succinate. Small amounts of acetate are also produced. The results of this study suggest that α-ketocarboxylic acids produced by mineral photoelectrochemistry could have participated in a viable enzyme-free cycle for carbon fixation in an environment where light, sulfide minerals, carbon dioxide, and other organic compounds interacted on prebiotic Earth.

  20. Methylcitrate cycle defines the bactericidal essentiality of isocitrate lyase for survival of Mycobacterium tuberculosis on fatty acids

    PubMed Central

    Eoh, Hyungjin; Rhee, Kyu Y.

    2014-01-01

    Few mutations attenuate Mycobacterium tuberculosis (Mtb) more profoundly than deletion of its isocitrate lyases (ICLs). However, the basis for this attenuation remains incompletely defined. Mtb’s ICLs are catalytically bifunctional isocitrate and methylisocitrate lyases required for growth on even and odd chain fatty acids. Here, we report that Mtb’s ICLs are essential for survival on both acetate and propionate because of its methylisocitrate lyase (MCL) activity. Lack of MCL activity converts Mtb’s methylcitrate cycle into a “dead end” pathway that sequesters tricarboxylic acid (TCA) cycle intermediates into methylcitrate cycle intermediates, depletes gluconeogenic precursors, and results in defects of membrane potential and intrabacterial pH. Activation of an alternative vitamin B12-dependent pathway of propionate metabolism led to selective corrections of TCA cycle activity, membrane potential, and intrabacterial pH that specifically restored survival, but not growth, of ICL-deficient Mtb metabolizing acetate or propionate. These results thus resolve the biochemical basis of essentiality for Mtb’s ICLs and survival on fatty acids. PMID:24639517

  1. Artificial Autopolyploidization Modifies the Tricarboxylic Acid Cycle and GABA Shunt in Arabidopsis thaliana Col-0

    NASA Astrophysics Data System (ADS)

    Vergara, Fredd; Kikuchi, Jun; Breuer, Christian

    2016-05-01

    Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and γ-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes.

  2. Artificial Autopolyploidization Modifies the Tricarboxylic Acid Cycle and GABA Shunt in Arabidopsis thaliana Col-0

    PubMed Central

    Vergara, Fredd; Kikuchi, Jun; Breuer, Christian

    2016-01-01

    Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and γ-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes. PMID:27212081

  3. Artificial Autopolyploidization Modifies the Tricarboxylic Acid Cycle and GABA Shunt in Arabidopsis thaliana Col-0.

    PubMed

    Vergara, Fredd; Kikuchi, Jun; Breuer, Christian

    2016-01-01

    Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and γ-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes. PMID:27212081

  4. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    EPA Science Inventory

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  5. Decreased glycolytic and tricarboxylic acid cycle intermediates coincide with peripheral nervous system oxidative stress in a murine model of type 2 diabetes

    PubMed Central

    Hinder, Lucy M.; Vivekanandan-Giri, Anuradha; McLean, Lisa L.; Pennathur, Subramaniam; Feldman, Eva L.

    2013-01-01

    Diabetic neuropathy (DN) is the most common complication of diabetes and is characterized by distal-to-proximal loss of peripheral nerve axons. The idea of tissue-specific pathological alterations in energy metabolism in diabetic complications-prone tissues is emerging. Altered nerve metabolism in type 1 diabetes models is observed; however, therapeutic strategies based on these models offer limited efficacy to type 2 diabetic patients with DN. Therefore, understanding how peripheral nerves metabolically adapt to the unique type 2 diabetic environment is critical to develop disease-modifying treatments. In the current study, we utilized targeted LC/MS/MS to characterize the glycolytic and tricarboxylic acid (TCA) cycle metabolomes in sural nerve, sciatic nerve and dorsal root ganglia (DRG) from male type 2 diabetic mice (BKS.Cg-m+/+Leprdb; db/db) and controls (db/+). We report depletion of glycolytic intermediates in diabetic sural nerve and sciatic nerve (glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate (sural nerve only), 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, lactate), with no significant changes in DRG. Citrate and isocitrate TCA cycle intermediates were decreased in sural nerve, sciatic nerve and DRG from diabetic mice. Utilizing LC/ESI/MS/MS and HPLC methods, we also observed increased protein and lipid oxidation (nitrotyrosine; hydroxyoctadecadienoic acids, HODEs) in db/db tissue, with a proximal-to-distal increase in oxidative stress, with associated decreased aconitase enzyme activity. We propose a preliminary model, whereby the greater change in metabolomic profile, increase in oxidative stress, and decrease in TCA cycle enzyme activity may cause distal peripheral nerve to rely on truncated TCA cycle metabolism in the type 2 diabetes environment. PMID:23086140

  6. Genetic Evidence for Bacterial Chemolithoautotrophy Based on the Reductive Tricarboxylic Acid Cycle in Groundwater Systems

    PubMed Central

    Alfreider, Albin; Vogt, Carsten

    2012-01-01

    Geologically and chemically distinct aquifers were screened for the presence of two genes coding for key enzymes of the reverse tricarboxylic acid (rTCA) cycle in autotrophic bacteria, 2-oxoglutarate : ferredoxin oxidoreductase (oorA) and the beta subunit of ATP citrate lyase enzymes (aclB). From 42 samples investigated, aclB genes were detected in two and oorA genes in six samples retrieved from polluted and sulfidic aquifers. aclB genes were represented by a single phylotype of almost identical sequences closely affiliated with chemolithoautotrophic Sulfurimonas species. In contrast, sequences analysis of oorA genes revealed diverse phylotypes mainly related to sequences from cultivation-independent studies. PMID:22791056

  7. Citric acid as the last therapeutic approach in an acute life-threatening metabolic decompensation of propionic acidaemia.

    PubMed

    Siekmeyer, Manuela; Petzold-Quinque, Stefanie; Terpe, Friederike; Beblo, Skadi; Gebhardt, Rolf; Schlensog-Schuster, Franziska; Kiess, Wieland; Siekmeyer, Werner

    2013-01-01

    The tricarboxylic acid (TCA) cycle represents the key enzymatic steps in cellular energy metabolism. Once the TCA cycle is impaired in case of inherited metabolic disorders, life-threatening episodes of metabolic decompensation and severe organ failure can arise. We present the case of a 6 ½-year-old girl with propionic acidaemia during an episode of acute life-threatening metabolic decompensation and severe lactic acidosis. Citric acid given as an oral formulation showed the potential to sustain the TCA cycle flux. This therapeutic approach may become a treatment option in a situation of acute metabolic crisis, possibly preventing severe disturbance of energy metabolism. PMID:23412866

  8. MicroTCA and AdvancedTCA equipment evaluation and customization for LHC experiments

    NASA Astrophysics Data System (ADS)

    Di Cosmo, M.; Bobillier, V.; Haas, S.; Joos, M.; Mico, S.; Vasey, F.

    2015-01-01

    The MicroTCA and AdvancedTCA industry standards are candidate modular electronics platforms for the upgrade of the current generation of high energy physics experiments at CERN. The PH-ESE group at CERN launched an xTCA evaluation project with the aim of performing technical evaluations and providing support for commercially available components. Over the past years, different equipment from different vendors has been acquired and evaluated. This paper summarizes our evaluation results of commercial MicroTCA and AdvancedTCA equipment. Special emphasis is put on the component requirements to be defined in view of future equipment procurement. Customized prototypes developed according to these generic specifications are presented for the first time.

  9. ATCA/muTCA for Physics

    SciTech Connect

    Jezynski, Tomasz; Larsen, Raymond; Le Du, Patrick; /Lyon, IPN

    2012-06-14

    ATCA/{mu}TCA platforms are attractive because of the modern serial link architecture, high availability features and many packaging options. Less-demanding availability applications can be met economically by scaling back speed and redundancy. The ATCA specification was originally targeted for the Telecom industry but has gained recently a much wider user audience. The purpose of this paper is to report on present hardware and software R and D efforts where ATCA and {mu}TCA are planned, already being used or in development using selected examples for accelerator and detectors in the Physics community. It will present also the status of a proposal for physics extensions to ATCA/{mu}TCA specifications to promote inter-operability of laboratory and industry designs for physics.

  10. Interconnection between tricarboxylic acid cycle and energy generation in microbial fuel cell performed by desulfuromonas acetoxidans IMV B-7384

    NASA Astrophysics Data System (ADS)

    Vasyliv, Oresta M.; Maslovska, Olga D.; Ferensovych, Yaroslav P.; Bilyy, Oleksandr I.; Hnatush, Svitlana O.

    2015-05-01

    Desulfuromonas acetoxidans IMV B-7384 is exoelectrogenic obligate anaerobic sulfur-reducing bacterium. Its one of the first described electrogenic bacterium that performs complete oxidation of an organic substrate with electron transfer directly to the electrode in microbial fuel cell (MFC). This bacterium is very promising for MFC development because of inexpensive cultivation medium, high survival rate and selective resistance to various heavy metal ions. The size of D. acetoxidans IMV B-7384 cells is comparatively small (0.4-0.8×1-2 μm) that is highly beneficial while application of porous anode material because of complete bacterial cover of an electrode area with further significant improvement of the effectiveness of its usage. The interconnection between functioning of reductive stage of tricarboxylic acid (TCA) cycle under anaerobic conditions, and MFC performance was established. Malic, pyruvic, fumaric and succinic acids in concentration 42 mM were separately added into the anode chamber of MFC as the redox agents. Application of malic acid caused the most stabile and the highest power generation in comparison with other investigated organic acids. Its maximum equaled 10.07±0.17mW/m2 on 136 hour of bacterial cultivation. Under addition of pyruvic, succinic and fumaric acids into the anode chamber of MFC the maximal power values equaled 5.80±0.25 mW/m2; 3.2±0.11 mW/m2, and 2.14±0.19 mW/m2 respectively on 40, 56 and 32 hour of bacterial cultivation. Hence the malic acid conversion via reductive stage of TCA cycle is shown to be the most efficient process in terms of electricity generation by D. acetoxidans IMV B-7384 in MFC under anaerobic conditions.

  11. Sulfuric acid-sulfur heat storage cycle

    DOEpatents

    Norman, John H.

    1983-12-20

    A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

  12. Metformin and phenformin deplete tricarboxylic acid cycle and glycolytic intermediates during cell transformation and NTPs in cancer stem cells

    PubMed Central

    Janzer, Andreas; German, Natalie J.; Gonzalez-Herrera, Karina N.; Asara, John M.; Haigis, Marcia C.; Struhl, Kevin

    2014-01-01

    Metformin, a first-line diabetes drug linked to cancer prevention in retrospective clinical analyses, inhibits cellular transformation and selectively kills breast cancer stem cells (CSCs). Although a few metabolic effects of metformin and the related biguanide phenformin have been investigated in established cancer cell lines, the global metabolic impact of biguanides during the process of neoplastic transformation and in CSCs is unknown. Here, we use LC/MS/MS metabolomics (>200 metabolites) to assess metabolic changes induced by metformin and phenformin in an Src-inducible model of cellular transformation and in mammosphere-derived breast CSCs. Although phenformin is the more potent biguanide in both systems, the metabolic profiles of these drugs are remarkably similar, although not identical. During the process of cellular transformation, biguanide treatment prevents the boost in glycolytic intermediates at a specific stage of the pathway and coordinately decreases tricarboxylic acid (TCA) cycle intermediates. In contrast, in breast CSCs, biguanides have a modest effect on glycolytic and TCA cycle intermediates, but they strongly deplete nucleotide triphosphates and may impede nucleotide synthesis. These metabolic profiles are consistent with the idea that biguanides inhibit mitochondrial complex 1, but they indicate that their metabolic effects differ depending on the stage of cellular transformation. PMID:25002509

  13. Alternative reactions at the interface of glycolysis and citric acid cycle in Saccharomyces cerevisiae.

    PubMed

    van Rossum, Harmen M; Kozak, Barbara U; Niemeijer, Matthijs S; Duine, Hendrik J; Luttik, Marijke A H; Boer, Viktor M; Kötter, Peter; Daran, Jean-Marc G; van Maris, Antonius J A; Pronk, Jack T

    2016-05-01

    Pyruvate and acetyl-coenzyme A, located at the interface between glycolysis and TCA cycle, are important intermediates in yeast metabolism and key precursors for industrially relevant products. Rational engineering of their supply requires knowledge of compensatory reactions that replace predominant pathways when these are inactivated. This study investigates effects of individual and combined mutations that inactivate the mitochondrial pyruvate-dehydrogenase (PDH) complex, extramitochondrial citrate synthase (Cit2) and mitochondrial CoA-transferase (Ach1) in Saccharomyces cerevisiae. Additionally, strains with a constitutively expressed carnitine shuttle were constructed and analyzed. A predominant role of the PDH complex in linking glycolysis and TCA cycle in glucose-grown batch cultures could be functionally replaced by the combined activity of the cytosolic PDH bypass and Cit2. Strongly impaired growth and a high incidence of respiratory deficiency in pda1Δ ach1Δ strains showed that synthesis of intramitochondrial acetyl-CoA as a metabolic precursor requires activity of either the PDH complex or Ach1. Constitutive overexpression of AGP2, HNM1, YAT2, YAT1, CRC1 and CAT2 enabled the carnitine shuttle to efficiently link glycolysis and TCA cycle in l-carnitine-supplemented, glucose-grown batch cultures. Strains in which all known reactions at the glycolysis-TCA cycle interface were inactivated still grew slowly on glucose, indicating additional flexibility at this key metabolic junction. PMID:26895788

  14. 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.

  15. Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals.

    PubMed

    Champagne, Cory D; Houser, Dorian S; Fowler, Melinda A; Costa, Daniel P; Crocker, Daniel E

    2012-08-01

    Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals (Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F(1,13) = 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals. PMID:22673783

  16. MicroTCA and AdvancedTCA equipment evaluation and developments for LHC experiments

    NASA Astrophysics Data System (ADS)

    Bobillier, V.; Haas, S.; Joos, M.; Mendez, J.; Mico, S.; Vasey, F.

    2016-02-01

    The MicroTCA (MTCA) and AdvancedTCA (ATCA) industry standards have been selected as the platform for many of the current and planned upgrades of the off-detector electronic systems of two of the LHC experiments at CERN. We present a status update from an ongoing project to evaluate commercial MTCA and ATCA components with particular emphasis on infrastructure equipment such as shelves and power-supplies. Shelves customized for use in the existing LHC rack infrastructure have been tested, and electrical and cooling measurements and simulations were performed. In-house developments for hardware platform management will also be shown.

  17. SdhE-dependent formation of a functional Acetobacter pasteurianus succinate dehydrogenase in Gluconobacter oxydans--a first step toward a complete tricarboxylic acid cycle.

    PubMed

    Kiefler, Ines; Bringer, Stephanie; Bott, Michael

    2015-11-01

    The obligatory aerobic α-proteobacterium Gluconobacter oxydans 621H possesses an unusual metabolism in which the majority of the carbohydrate substrates are incompletely oxidized in the periplasm and only a small fraction is metabolized in the cytoplasm. The cytoplasmic oxidation capabilities are limited due to an incomplete tricarboxylic acid (TCA) cycle caused by the lack of succinate dehydrogenase (Sdh) and succinyl-CoA synthetase. As a first step to test the consequences of a functional TCA cycle for growth, metabolism, and bioenergetics of G. oxydans, we attempted to establish a heterologous Sdh in this species. Expression of Acetobacter pasteurianus sdhCDAB in G. oxydans did not yield an active succinate dehydrogenase. Co-expression of a putative sdhE gene from A. pasteurianus, which was assumed to encode an assembly factor for covalent attachment of flavin adenine dinucleotide (FAD) to SdhA, stimulated Sdh activity up to 400-fold to 4.0 ± 0.4 U (mg membrane protein)(‒1). The succinate/oxygen reductase activity of membranes was 0.68 ± 0.04 U (mg membrane protein)(‒1), indicating the formation of functional Sdh complex capable of transferring electrons from succinate to ubiquinone. A. pasteurianus SdhE could be functionally replaced by SdhE from the γ-proteobacterium Serratia sp. According to these results, the accessory protein SdhE was necessary and sufficient for heterologous synthesis of an active A. pasteurianus Sdh in G. oxydans. Studies with the Sdh-positive G. oxydans strain provided evidence for a limited functionality of the TCA cycle despite the absence of succinyl-CoA synthetase. PMID:26399411

  18. Cell cycle nucleic acids, polypeptides and uses thereof

    DOEpatents

    Gordon-Kamm, William J.; Lowe, Keith S.; Larkins, Brian A.; Dilkes, Brian R.; Sun, Yuejin

    2007-08-14

    The invention provides isolated nucleic acids and their encoded proteins that are involved in cell cycle regulation. The invention further provides recombinant expression cassettes, host cells, transgenic plants, and antibody compositions. The present invention provides methods and compositions relating to altering cell cycle protein content, cell cycle progression, cell number and/or composition of plants.

  19. Sulfuric acid on Europa and the radiolytic sulfur cycle

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.; Johnson, R. E.; Anderson, M. S.

    1999-01-01

    A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

  20. A phylogenetic approach to the early evolution of autotrophy: the case of the reverse TCA and the reductive acetyl-CoA pathways.

    PubMed

    Becerra, Arturo; Rivas, Mario; García-Ferris, Carlos; Lazcano, Antonio; Peretó, Juli

    2014-06-01

    In recent decades, a number of hypotheses on the autotrophic origin of life have been presented. These proposals invoke the emergence of reaction networks leading from CO or CO₂ to the organic molecules required for life. It has also been suggested that the last (universal) common ancestor (LCA or LUCA) of all extant cell lineages was a chemolitho-autotrophic thermophilic anaerobe. The antiquity of some carbon fixation pathways, the phylogenetic basal distribution of some autotrophic organisms, and the catalytic properties of iron-sulfur minerals have been advanced in support of these ideas. Here we critically examine the phylogenetic distribution and evolution of enzymes that are essential for two of the most ancient autotrophic means of metabolism: the reductive tricarboxylic acid (rTCA) cycle and the reductive acetyl-CoA pathway. Phylogenetic analysis of citryl-CoA synthetase and of citryl-CoA lyase, key enzymatic components of the rTCA cycle, and of CO dehydrogenase/acetyl-CoA synthase, a key enzyme in the reductive acetyl-CoA pathway, revealed that all three enzymes have undergone major lateral transfer events and therefore cannot be used as proof of the LCA's metabolic abilities nor as evidence of an autotrophic origin of life. PMID:26418853

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

    PubMed Central

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

    2016-01-01

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

  2. Blood metabolomics analysis identifies abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism in bipolar disorder

    PubMed Central

    Yoshimi, Noriko; Futamura, Takashi; Kakumoto, Keiji; Salehi, Alireza M.; Sellgren, Carl M.; Holmén-Larsson, Jessica; Jakobsson, Joel; Pålsson, Erik; Landén, Mikael; Hashimoto, Kenji

    2016-01-01

    Background Bipolar disorder (BD) is a severe and debilitating psychiatric disorder. However, the precise biological basis remains unknown, hampering the search for novel biomarkers. We performed a metabolomics analysis to discover novel peripheral biomarkers for BD. Methods We quantified serum levels of 116 metabolites in mood-stabilized male BD patients (n = 54) and age-matched male healthy controls (n = 39). Results After multivariate logistic regression, serum levels of pyruvate, N-acetylglutamic acid, α-ketoglutarate, and arginine were significantly higher in BD patients than in healthy controls. Conversely, serum levels of β-alanine, and serine were significantly lower in BD patients than in healthy controls. Chronic (4-weeks) administration of lithium or valproic acid to adult male rats did not alter serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, or arginine, but lithium administration significantly increased serum levels of α-ketoglutarate. Conclusions The metabolomics analysis demonstrated altered serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, and arginine in BD patients. General significance The present findings suggest that abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism play a role in the pathogenesis of BD. PMID:27114925

  3. Commercial Alloys for Sulfuric Acid Vaporization in Thermochemical Hydrogen Cycles

    SciTech Connect

    Thomas M. Lillo; Karen M. Delezene-Briggs

    2005-10-01

    Most thermochemical cycles being considered for producing hydrogen include a processing stream in which dilute sulfuric acid is concentrated, vaporized and then decomposed over a catalyst. The sulfuric acid vaporizer is exposed to highly aggressive conditions. Liquid sulfuric acid will be present at a concentration of >96 wt% (>90 mol %) H2SO4 and temperatures exceeding 400oC [Brown, et. al, 2003]. The system will also be pressurized, 0.7-3.5 MPa, to keep the sulfuric acid in the liquid state at this temperature and acid concentration. These conditions far exceed those found in the commercial sulfuric acid generation, regeneration and handling industries. Exotic materials, e.g. ceramics, precious metals, clad materials, etc., have been proposed for this application [Wong, et. al., 2005]. However, development time, costs, reliability, safety concerns and/or certification issues plague such solutions and should be considered as relatively long-term, optimum solutions. A more cost-effective (and relatively near-term) solution would be to use commercially-available metallic alloys to demonstrate the cycle and study process variables. However, the corrosion behavior of commercial alloys in sulfuric acid is rarely characterized above the natural boiling point of concentrated sulfuric acid (~250oC at 1 atm). Therefore a screening study was undertaken to evaluate the suitability of various commercial alloys for concentration and vaporization of high-temperature sulfuric acid. Initially alloys were subjected to static corrosion tests in concentrated sulfuric acid (~95-97% H2SO4) at temperatures and exposure times up to 200oC and 480 hours, respectively. Alloys with a corrosion rate of less than 5 mm/year were then subjected to static corrosion tests at a pressure of 1.4 MPa and temperatures up to 375oC. Exposure times were shorter due to safety concerns and ranged from as short as 5 hours up to 144 hours. The materials evaluated included nickel-, iron- and cobalt

  4. Preliminary Evaluation of Nonlinear Effects on TCA Flutter

    NASA Technical Reports Server (NTRS)

    Arslan, Alan E.; Hartwich, Peter M.; Baker, Myles L.

    1998-01-01

    The objective of this study is to investigate the effect of nonlinear aerodynamics, especially at high angles-of-attack with leading-edge separation, on the TCA flutter properties at transonic speeds. In order to achieve that objective, flutter simulations with Navier-Stokes CFD must be performed. To this end, time-marching Navier-Stokes solutions are computed for the TCA wing/body configuration at high angles-of-attack in transonic flight regimes. The approach is to perform non-linear flutter calculations on the TCA at two angles-of-attack, the first one being a case with attached flow (a=2.8 degrees) and the second one being a high angle-of-attack case with a wing leading edge vortex (a=12.11 degrees). Comparisons of the resulting histories and frequency damping information for both angles-of-attack will evaluate the impact of high-alpha aerodynamics on flutter.

  5. Cross-talk between branched-chain amino acids and hepatic mitochondria is compromised in nonalcoholic fatty liver disease

    PubMed Central

    Kalavalapalli, Srilaxmi; Bril, Fernando; Garrett, Timothy J.; Nautiyal, Manisha; Mathew, Justin T.; Williams, Caroline M.; Cusi, Kenneth

    2015-01-01

    Elevated plasma branched-chain amino acids (BCAA) in the setting of insulin resistance have been relevant in predicting type 2 diabetes mellitus (T2DM) onset, but their role in the etiology of hepatic insulin resistance remains uncertain. We determined the link between BCAA and dysfunctional hepatic tricarboxylic acid (TCA) cycle, which is a central feature of hepatic insulin resistance and nonalcoholic fatty liver disease (NAFLD). Plasma metabolites under basal fasting and euglycemic hyperinsulinemic clamps (insulin stimulation) were measured in 94 human subjects with varying degrees of insulin sensitivity to identify their relationships with insulin resistance. Furthermore, the impact of elevated BCAA on hepatic TCA cycle was determined in a diet-induced mouse model of NAFLD, utilizing targeted metabolomics and nuclear magnetic resonance (NMR)-based metabolic flux analysis. Insulin stimulation revealed robust relationships between human plasma BCAA and indices of insulin resistance, indicating chronic metabolic overload from BCAA. Human plasma BCAA and long-chain acylcarnitines also showed a positive correlation, suggesting modulation of mitochondrial metabolism by BCAA. Concurrently, mice with NAFLD failed to optimally induce hepatic mTORC1, plasma ketones, and hepatic long-chain acylcarnitines, following acute elevation of plasma BCAA. Furthermore, elevated BCAA failed to induce multiple fluxes through hepatic TCA cycle in mice with NAFLD. Our data suggest that BCAA are essential to mediate efficient channeling of carbon substrates for oxidation through mitochondrial TCA cycle. Impairment of BCAA-mediated upregulation of the TCA cycle could be a significant contributor to mitochondrial dysfunction in NAFLD. PMID:26058864

  6. Analysis and Multipoint Design of the TCA Concept

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Buning, Pieter G.

    1999-01-01

    The goal in this effort is to analyze the baseline TCA concept at transonic and supersonic cruise, then apply the natural flow wing design concept to obtain multipoint performance improvements. Analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between the overset grids.

  7. Bioluminescence regenerative cycle (BRC) system for nucleic acid quantification assays

    NASA Astrophysics Data System (ADS)

    Hassibi, Arjang; Lee, Thomas H.; Davis, Ronald W.; Pourmand, Nader

    2003-07-01

    A new label-free methodology for nucleic acid quantification has been developed where the number of pyrophosphate molecules (PPi) released during polymerization of the target nucleic acid is counted and correlated to DNA copy number. The technique uses the enzymatic complex of ATP-sulfurylase and firefly luciferase to generate photons from PPi. An enzymatic unity gain positive feedback is also implemented to regenerate the photon generation process and compensate any decay in light intensity by self regulation. Due to this positive feedback, the total number of photons generated by the bioluminescence regenerative cycle (BRC) can potentially be orders of magnitude higher than typical chemiluminescent processes. A system level kinetic model that incorporates the effects of contaminations and detector noise was used to show that the photon generation process is in fact steady and also proportional to the nucleic acid quantity. Here we show that BRC is capable of detecting quantities of DNA as low as 1 amol (10-18 mole) in 40μlit aqueous solutions, and this enzymatic assay has a controllable dynamic range of 5 orders of magnitude. The sensitivity of this technology, due to the excess number of photons generated by the regenerative cycle, is not constrained by detector performance, but rather by possible PPi or ATP (adenosine triphosphate) contamination, or background bioluminescence of the enzymatic complex.

  8. Phosphorus constrains accelerated nitrogen cycling in limed acidic forests

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Shaw, A. N.; Kluber, L. A.; Burke, D. J.; Carrino-Kyker, S. R.; Smemo, K. A.

    2011-12-01

    Anthropogenic deposition can increase phosphorus (P) limitation by abiotic and biotic means. Soil acidification can remove P from available pools and nitrogen (N) deposition can increase the demand for P. We reason that chronic acidic deposition is promoting P limitation in acidic hardwood forests and thereby altering N cycling. The objectives of this study were to investigate the interactive influence of P availability and soil pH on N and P cycling and availability to determine if the response varies between two physiographic regions experiencing similar chronic acidic deposition. We addressed these objectives by experimentally manipulating soil pH, P, or both in strongly acidic glaciated and unglaciated hardwood forests in eastern Ohio, USA. Our results suggest complex interactions between P, soil pH, and the N cycle. Glaciated soils were found to be more N-saturated with nitrification rates 18 times greater than in unglaciated soils. Elevating pH, with or without added P, doubled nitrification rates in glaciated soils. For unglaciated soils, raising pH increased nitrification 10-fold, but increased nitrification only 5-fold in combination with P. This result suggests raising soil pH lowered the demand of soil N, or directly stimulated nitrifying activity, and that increasing P availability could limit N availability. To various degrees, readily available P was geochemically or biologically immobilized in all treatments, suggesting chronic P deficiency in these ecosystems. Phosphorus immobilization decreased as soil pH was elevated, but elevated P either had no effect (glaciated) or doubled P immobilization rates (unglaciated). These results suggest that raising soil pH reduces microbial P limitation for phosphate, whereas adding P appears to make phosphate scarcer. We suggest that P plays an important role in N transformations and cycling, but appears more important in unglaciated soils than in glaciated soils. Chronic soil acidification may have a greater

  9. Fatty acid biosynthesis during the life cycle of Debaryomyces etchellsii.

    PubMed

    Arous, Fatma; Mechichi, Tahar; Nasri, Moncef; Aggelis, George

    2016-07-01

    Fatty acid biosynthesis during the life cycle of the ascomycetous yeast Debaryomyces etchellsii cultivated on a non-fermentable substrate, i.e. glycerol, in nitrogen rich media (NRM) and nitrogen limited media (NLM) has been studied. Although considerable activities of key lipogenic enzymes, such as ATP citrate lyase (ACL) and malic enzyme (ME), were detected in vegetative cells during asexual proliferation (which occurred in the first growth stages in both NRM and NLM), lipid accumulation was restricted due to the high activities of NAD+-isocitrate dehydrogenase (NAD+-ICDH). A similar enzymatic profile has been found in ascii and free ascospores produced in NRM; thus lipid accumulation was low. On the contrary, very high activities of both ACL and ME and low activities of NAD+-ICDH were detected in ascii and free ascospores produced in NLM resulting in lipid accumulation. Neutral lipids (NL) were the predominant fraction of cellular lipids produced in vegetative cells and ascospores in both NRM and NLM. On the other hand, phospholipids (P) were the major polar lipids while glycolipids (G) were synthesized in low proportions. During transition from asexual to sexual phase, the percentage of NL increased with a significant decrease of P and, to a lesser extent, of G. High quantities of linoleic acid were found esterified in polar lipids, especially in P, during the vegetative stage of growth, while, with a few exceptions, during transition from asexual to sexual stage, linoleic acid concentration decreased markedly, mainly in P, while oleic acid concentration increased. PMID:27129978

  10. Inhibition of akt phosphorylation diminishes mitochondrial biogenesis regulators, tricarboxylic acid cycle activity and exacerbates recognition memory deficit in rat model of Alzheimer's disease.

    PubMed

    Shaerzadeh, Fatemeh; Motamedi, Fereshteh; Khodagholi, Fariba

    2014-11-01

    3-Methyladenine (3-MA), as a PI3K inhibitor, is widely used for inhibition of autophagy. Inhibition of PI3K class I leads to inhibition of Akt phosphorylation, a central molecule involved in diverse arrays of intracellular cascades in nervous system. Accordingly, in the present study, we aimed to determine the alterations of specific mitochondrial biogenesis markers and mitochondrial function in 3-MA-injected rats following amyloid beta (Aβ) insult. Our data revealed that inhibition of Akt phosphorylation downregulates master regulator of mitochondrial biogenesis, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Our data also showed that decrease in PGC-1α level presumably is due to decrease in the phosphorylation of cAMP-response element binding and AMP-activated kinase, two upstream activators of PGC-1α. As a consequence, the level of some mitochondrial biogenesis factors including nuclear respiratory factor-1, mitochondrial transcription factor A, and Cytochrome c decreased significantly. Also, activities of tricarboxylic acid cycle (TCA) enzymes such as Aconitase, a-ketoglutarate dehydrogenase, and malate dehydrogenase reduced in the presence of 3-MA with or without Aβ insult. Decrease in mitochondrial biogenesis factors and TCA enzyme activity in the rats receiving 3-MA and Aβ were more compared to the rats that received either alone; indicating the additive destructive effects of these two agents. In agreement with our molecular results, data obtained from behavioral test (using novel objective recognition test) indicated that inhibition of Akt phosphorylation with or without Aβ injection impaired novel recognition (non-spatial) memory. Our results suggest that 3-MA amplified deleterious effects of Aβ by targeting central molecule Akt. PMID:25135709

  11. Regulating Pyruvate Carboxylase in the Living Culture of Aspergillus Terreus Nrrl 1960 by L-Aspartate for Enhanced Itaconic Acid Production.

    PubMed

    Songserm, Pajareeya; Thitiprasert, Sitanan; Tolieng, Vasana; Piluk, Jiraporn; Tanasupawat, Somboon; Assabumrungrat, Sutthichai; Yang, Shang-Tian; Karnchanatat, Aphichart; Thongchul, Nuttha

    2015-10-01

    Aspergillus terreus was reported as the promising fungal strain for itaconic acid; however, the commercial production suffers from the low yield. Low production yield was claimed as the result of completing the tricarboxylic acid (TCA) cycle towards biomass synthesis while under limiting phosphate and nitrogen; TCA cycle was somewhat shunted and consequently, the metabolite fluxes move towards itaconic acid production route. By regulating enzymes in TCA cycle, it is believed that itaconic acid production can be improved. One of the key responsible enzymes involved in itaconic acid production was triggered in this study. Pyruvate carboxylase was allosterically inhibited by L-aspartate. The presence of 10 mM L-aspartate in the production medium directly repressed PC expression in the living A. terreus while the limited malate flux regulated the malate/citrate antiporters resulting in the increasing cis-aconitate decarboxylase activity to simultaneously convert cis-aconitate, citrate isomer, into itaconic acid. The transport of cis-aconitate via the antiporters induced citrate synthase and 6-phosphofructo-1-kinase activities in response to balance the fluxes of TCA intermediates. Successively, itaconic acid production yield and final concentration could be improved by 8.33 and 60.32 %, respectively, compared to those obtained from the control fermentation with the shortened lag time to produce itaconic acid during the production phase. PMID:26208692

  12. /sup 13/C NMR study of effects of fasting and diabetes on the metabolism of pyruvate in the tricarboxylic acid cycle and of the utilization of pyruvate and ethanol in lipogenesis in perfused rat liver

    SciTech Connect

    Cohen, S.M.

    1987-01-27

    /sup 13/C NMR has been used to study the competition of pyruvate dehydrogenase with pyruvate carboxylase for entry of pyruvate into the tricarboxylic acid (TCA) cycle in perfused liver from streptozotocin-diabetic and normal donor rats. The relative proportion of pyruvate entering the TCA cycle by these two routes was estimated from the /sup 13/C enrichments at the individual carbons of glutamate when (3-/sup 13/C)alanine was the only exogenous substrate present. In this way, the proportion of pyruvate entering by the pyruvate dehydrogenase route relative to the pyruvate carboxylase route was determined to be 1:1.2 +/- 0.1 in liver from fed controls, 1:7.7 +/- 2 in liver from 24-fasted controls, and 1:2.6 +/- 0.3 in diabetic liver. Pursuant to this observation that conversion of pyruvate to acetyl coenzyme A (acetyl-CoA) was greatest in perfused liver from fed controls, the incorporation of /sup 13/C label into fatty acids was monitored in this liver preparation. With the exception of the repeating methylene carbons, fatty acyl carbons labeled by (1-/sup 13/C)acetyl-CoA (from (2-/sup 13/C)pyruvate) gave rise to resonances distinguishable on the basis of chemical shift from those observed when label was introduced by (3-/sup 13/C)alanine plus (2-/sup 13/C)ethanol, which are converted to (2-/sup 13/C)acetyl-CoA. Thus, measurement of /sup 13/C enrichment at several specific sites in the fatty acyl chains in time-resolved spectra of perfused liver offers a novel way of monitoring the kinetics of the biosynthesis of fatty acids. In addition to obtaining the rate of lipogenesis, it was possible to distinguish the contributions of chain elongation from those of the de novo synthesis pathway and to estimate the average chain length of the /sup 13/C-labeled fatty acids produced.

  13. Inorganic Nitrogen Cycling in an Extreme Acid Mine Drainage Site

    NASA Astrophysics Data System (ADS)

    Kalnejais, L. H.; Smith, R. L.; Nordstrom, D. K.; Banfield, J. F.

    2006-12-01

    Weathering of the massive sulfide ore body at Iron Mountain, northern California has generated sulfuric acid solutions with pH values ranging from 0.5 to 1, temperatures up to 50°C and high concentrations of toxic metals. Communities of microorganisms catalyze the oxidation of iron and sulfur that generates this extreme environment. The nitrogen requirements of these organisms and the nitrogen cycling within these waters are not understood. By adapting the chemiluminescence detection method of Baeseman (2004) we have constrained the stability of nitrate and nitrite species in acidic, high ferrous iron solutions and have measured a time series of the nitrate concentrations at sites within Iron Mountain. The half-life of nitrite is less than an hour due to reactions with ferrous ions, while nitrate is found at concentrations of up to 10 μM within the mine. By coupling this information with geochemical and microbial community information at each site together with culture enrichment studies using various nitrogen sources we hope to gain insight into the pathways of nitrogen utilization in this extreme environment. References Baeseman, J.L. (2004) Denitrification in acid-impacted mountain stream sediments. Ph.D. Dissertation, University of Colorado, Department of Civil, Environmental, and Architectural Engineering.

  14. Oxygenated monoterpenes citral and carvacrol cause oxidative damage in Escherichia coli without the involvement of tricarboxylic acid cycle and Fenton reaction.

    PubMed

    Chueca, Beatriz; Pagán, Rafael; García-Gonzalo, Diego

    2014-10-17

    Oxygenated monoterpenes citral and carvacrol are common constituents of many essential oils (EOs) that have been extensively studied as antimicrobial agents but whose mechanisms of microbial inactivation have not been totally elucidated. A recent study described a mechanism of Escherichia coli death for (+)-limonene, a hydrocarbon monoterpene also frequently present in EOs, similar to the common mechanism proposed for bactericidal antibiotics. This mechanism involves the formation of Fenton-mediated hydroxyl radical, a reactive oxygen species (ROS), via tricarboxylic acid (TCA) cycle, which would ultimately inactivate cells. Our objective was to determine whether E. coli MG1655 inactivation by citral and carvacrol follows a similar mechanism of cell death. Challenging experiments with 300μL/L citral and 100μL/L carvacrol inactivated at least 2.5log10cycles of exponentially growing cells in 3h under aerobic conditions. The presence of thiourea (an ROS scavenger) reduced cell inactivation in 2log10cycles, demonstrating the role of ROS in cell death. Decreased resistance of a ΔrecA mutant (deficient in an enzyme involved in SOS response to DNA damage) indicated that citral and carvacrol caused oxidative damage to DNA. Although the mechanism of E. coli inactivation by carvacrol and citral was similarly mediated by ROS, their formation did not follow the same pathways described for (+)-limonene and bactericidal drugs because neither Fenton reaction nor NADH production via the TCA cycle was involved in cell death. Moreover, further experiments demonstrated antimicrobial activity of citral and carvacrol in anaerobic environments without the involvement of ROS. As a consequence, cell death by carvacrol and citral in anaerobiosis follows a different mechanism than that observed under aerobic conditions. These results demonstrated a different mechanism of inactivation by citral and carvacrol with regard to (+)-limonene and bactericidal antibiotics, indicating the

  15. Low-temperature Storage of Cucumbers Induces Changes in the Organic Acid Content and in Citrate Synthase Activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To elucidate the cause of reported pyruvate accumulation in chilled stored cucumbers (Cucumis sativus L.) cv. ‘Toppugurin’, we have examined differences in the extent of incorporation of acetate-1,2-14C into the tricarboxylic acid (TCA) cycle and the specific activity of the enzyme citrate synthase ...

  16. Acid wash of second cycle solvent in the recovery of uranium from phosphate rock

    SciTech Connect

    York, W.R.

    1984-02-07

    Entrainment of contaminated water in the organic phase and poor phase disengagement is prevented in the second cycle scrubber, in a two cycle-uranium recovery process, by washing the organic solvent stream containing entrained H/sub 3/PO/sub 4/ from the second cycle extractor, with a dilute aqueous sulfuric or nitric acid solution in an acid scrubber, prior to passing the solvent stream into the second cycle stripper.

  17. Materials study supporting thermochemical hydrogen cycle sulfuric acid decomposer design

    NASA Astrophysics Data System (ADS)

    Peck, Michael S.

    Increasing global climate change has been driven by greenhouse gases emissions originating from the combustion of fossil fuels. Clean burning hydrogen has the potential to replace much of the fossil fuels used today reducing the amount of greenhouse gases released into the atmosphere. The sulfur iodine and hybrid sulfur thermochemical cycles coupled with high temperature heat from advanced nuclear reactors have shown promise for economical large-scale hydrogen fuel stock production. Both of these cycles employ a step to decompose sulfuric acid to sulfur dioxide. This decomposition step occurs at high temperatures in the range of 825°C to 926°C dependent on the catalysis used. Successful commercial implementation of these technologies is dependent upon the development of suitable materials for use in the highly corrosive environments created by the decomposition products. Boron treated diamond film was a potential candidate for use in decomposer process equipment based on earlier studies concluding good oxidation resistance at elevated temperatures. However, little information was available relating the interactions of diamond and diamond films with sulfuric acid at temperatures greater than 350°C. A laboratory scale sulfuric acid decomposer simulator was constructed at the Nuclear Science and Engineering Institute at the University of Missouri-Columbia. The simulator was capable of producing the temperatures and corrosive environments that process equipment would be exposed to for industrialization of the sulfur iodide or hybrid sulfur thermochemical cycles. A series of boron treated synthetic diamonds were tested in the simulator to determine corrosion resistances and suitability for use in thermochemical process equipment. These studies were performed at twenty four hour durations at temperatures between 600°C to 926°C. Other materials, including natural diamond, synthetic diamond treated with titanium, silicon carbide, quartz, aluminum nitride, and Inconel

  18. Crassulacean acid metabolism-cycling in Euphorbia milii

    PubMed Central

    Herrera, Ana

    2013-01-01

    Crassulacean acid metabolism (CAM) occurs in many Euphorbiaceae, particularly Euphorbia, a genus with C3 and C4 species as well. With the aim of contributing to our knowledge of the evolution of CAM in this genus, this study examined the possible occurrence of CAM in Euphorbia milii, a species with leaf succulence and drought tolerance suggestive of this carbon fixation pathway. Leaf anatomy consisted of a palisade parenchyma, a spongy parenchyma and a bundle sheath with chloroplasts, which indicates the possible functioning of C2 photosynthesis. No evidence of nocturnal CO2 fixation was found in plants of E. milii either watered or under drought; watered plants had a low nocturnal respiration rate (R). After 12 days without watering, the photosynthetic rate (PN) decreased 85 % and nocturnal R was nearly zero. Nocturnal H+ accumulation (ΔH+) in watered plants was 18 ± 2 (corresponding to malate) and 18 ± 4 (citrate) μmol H+ (g fresh mass)−1. Respiratory CO2 recycling through acid synthesis contributed to a night-time water saving of 2 and 86 % in watered plants and plants under drought, respectively. Carbon isotopic composition (δ13C) was −25.2 ± 0.7 ‰ in leaves and −24.7 ± 0.1 ‰ in stems. Evidence was found for the operation of weak CAM in E. milii, with statistically significant ΔH+, no nocturnal CO2 uptake and values of δ13C intermediate between C3 and constitutive CAM plants; ΔH+ was apparently attributable to both malate and citrate. The results suggest that daily malate accumulation results from recycling of part of the nocturnal respiratory CO2, which helps explain the occurrence of an intermediate value of leaf δ13C. Euphorbia milii can be considered as a CAM-cycling species. The significance of the operation of CAM-cycling in E. milii lies in water conservation, rather than carbon acquisition. The possible occurrence of C2 photosynthesis merits research. PMID:23596548

  19. Crassulacean acid metabolism-cycling in Euphorbia milii.

    PubMed

    Herrera, Ana

    2013-01-01

    Crassulacean acid metabolism (CAM) occurs in many Euphorbiaceae, particularly Euphorbia, a genus with C3 and C4 species as well. With the aim of contributing to our knowledge of the evolution of CAM in this genus, this study examined the possible occurrence of CAM in Euphorbia milii, a species with leaf succulence and drought tolerance suggestive of this carbon fixation pathway. Leaf anatomy consisted of a palisade parenchyma, a spongy parenchyma and a bundle sheath with chloroplasts, which indicates the possible functioning of C2 photosynthesis. No evidence of nocturnal CO2 fixation was found in plants of E. milii either watered or under drought; watered plants had a low nocturnal respiration rate (R). After 12 days without watering, the photosynthetic rate (P N) decreased 85 % and nocturnal R was nearly zero. Nocturnal H(+) accumulation (ΔH(+)) in watered plants was 18 ± 2 (corresponding to malate) and 18 ± 4 (citrate) μmol H(+) (g fresh mass)(-1). Respiratory CO2 recycling through acid synthesis contributed to a night-time water saving of 2 and 86 % in watered plants and plants under drought, respectively. Carbon isotopic composition (δ(13)C) was -25.2 ± 0.7 ‰ in leaves and -24.7 ± 0.1 ‰ in stems. Evidence was found for the operation of weak CAM in E. milii, with statistically significant ΔH(+), no nocturnal CO2 uptake and values of δ(13)C intermediate between C3 and constitutive CAM plants; ΔH(+) was apparently attributable to both malate and citrate. The results suggest that daily malate accumulation results from recycling of part of the nocturnal respiratory CO2, which helps explain the occurrence of an intermediate value of leaf δ(13)C. Euphorbia milii can be considered as a CAM-cycling species. The significance of the operation of CAM-cycling in E. milii lies in water conservation, rather than carbon acquisition. The possible occurrence of C2 photosynthesis merits research. PMID:23596548

  20. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria

    SciTech Connect

    Thomas, Dennis G.; Jaramillo Riveri, Sebastian I.; Baxter, Douglas J.; Cannon, William R.

    2014-12-15

    We have applied a new stochastic simulation approach to predict the metabolite levels, energy flow, and material flux in the different oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on equations of state and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the selforganization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals, such as biofuels.

  1. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria.

    PubMed

    Thomas, Dennis G; Jaramillo-Riveri, Sebastian; Baxter, Douglas J; Cannon, William R

    2014-12-26

    We have applied a new stochastic simulation approach to predict the metabolite levels, material flux, and thermodynamic profiles of the oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on modeling states using statistical thermodynamics and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the self-organization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow, and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals. PMID:25495377

  2. Derivatization of the tricarboxylic acid intermediates with O-benzylhydroxylamine for liquid chromatography-tandem mass spectrometry detection.

    PubMed

    Tan, Bo; Lu, Zhaohai; Dong, Sucai; Zhao, Genshi; Kuo, Ming-Shang

    2014-11-15

    The tricarboxylic acid (TCA) cycle is an interface among glycolysis, lipid metabolism, and amino acid metabolism. Increasing interest in cancer metabolism has created a demand for rapid and sensitive methods for quantifying the TCA cycle intermediates and related organic acids. We have developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify the TCA cycle intermediates in a 96-well format after O-benzylhydroxylamine (O-BHA) derivatization under aqueous conditions. This method was validated for quantitation of all common TCA cycle intermediates with good sensitivity, including α-ketoglutarate, malate, fumarate, succinate, 2-hydroxyglutarate, citrate, oxaloacetate, pyruvate, isocitrate, and lactate using a 8-min run time in cancer cells and tissues. The method was used to detect and quantify changes in metabolite levels in cancer cells and tumor tissues treated with a pharmacological inhibitor of nicotinamide phosphoribosyl transferase (NAMPT). This method is rapid, sensitive, and reproducible, and it can be used to assess metabolic changes in cancer cells and tumor samples. PMID:25102203

  3. Biosynthesis of pyruvic acid from glucose by Blastobotrys adeninivorans.

    PubMed

    Kamzolova, Svetlana V; Morgunov, Igor G

    2016-09-01

    The ability of taxonomically different yeasts to synthesize pyruvic acid (PA) from glucose was studied. The study showed that many yeasts are able to produce PA from glucose under the condition of growth limitation by thiamine. This ability was found in the yeast Blastobotrys adeninivorans for the first time. The production (oversynthesis) of PA in this yeast can be explained by disturbance in the function of thiamine-dependent pyruvate dehydrogenase. Namely, the partial inhibition of this enzyme brings about the excretion of PA from the yeast cells. Due to incomplete inhibition of pyruvate dehydrogenase, the formation of acetyl-CoA continues, although at a lower level, maintaining the synthesis of α-ketoglutaric acid (KGA) in the tricarboxylic acid (TCA) cycle. KGA is no longer oxidized in the TCA cycle, because thiamine limitation inhibits α-ketoglutarate dehydrogenase. As a result, KGA is excreted from the yeast cells as a byproduct of PA oversynthesis. Furthermore, the increased level of KGA in the yeast cells inhibits NAD-dependent isocitrate dehydrogenase in the TCA cycle and enhances the production and excretion of citric acid, another byproduct of PA oversynthesis. During cultivation in a fermentor, the strain Blastobotrys adeninivorans VKM Y-2677 produced 43.2 g l(-1) PA from glucose with a product yield (YPA) of 0.77 g PA/g glucose. The proportion of PA to byproducts was 18:1 for KGA and 8:1 for citric acid. PMID:27221290

  4. The effect of propionic acid and valeric acid on the cell cycle in root meristems of Pisum sativum

    SciTech Connect

    Tramontano, W.A.; Yang, Shauyu; Delillo, A.R. )

    1990-01-01

    Propionic acid and valeric acid at 1mM reduced the mitotic index of root meristem cells of Pisum sativum to < 1% after 12 hr in aerated White's medium. This effect varied with different acid concentrations. After a 12 hr exposure to either acid, seedlings transferred to fresh medium without either acid, resumed their normal mitotic index after 12 hr, with a burst of mitosis 8 hr post-transfer. Exposure of root meristem cells to either acid also inhibited ({sup 3}H)-TdR incorporation. Neither acid significantly altered the distribution of meristematic cells in G1 and G2 after 12 hr. The incorporation of ({sup 3}H) - uridine was also unaltered by the addition of either acid. This information suggests that propionic acid and valeric acid, limit progression through the cell cycle by inhibiting DNA synthesis and arresting cells in G1 and G2. These results were consistent with previous data which utilized butyric acid.

  5. Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice

    NASA Astrophysics Data System (ADS)

    Meguro, Ayano; Sato, Yutaka

    2014-04-01

    We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes.

  6. Extraction, purification, methylation and GC-MS analysis of short-chain carboxylic acids for metabolic flux analysis.

    PubMed

    Tivendale, Nathan D; Jewett, Erin M; Hegeman, Adrian D; Cohen, Jerry D

    2016-08-15

    Dynamic metabolic flux analysis requires efficient and effective methods for extraction, purification and analysis of a plethora of naturally-occurring compounds. One area of metabolism that would be highly informative to study using metabolic flux analysis is the tricarboxylic acid (TCA) cycle, which consists of short-chain carboxylic acids. Here, we describe a newly-developed method for extraction, purification, derivatization and analysis of short-chain carboxylic acids involved in the TCA cycle. The method consists of snap-freezing the plant material, followed by maceration and a 12-15h extraction at -80 °C. The extracts are then subject to reduction (to stabilize β-keto acids), purified by strong anion exchange solid phase extraction and methylated with methanolic HCl. This method could also be readily adapted to quantify many other short-chain carboxylic acids. PMID:27348709

  7. Reductive photo-dechlorination (RPD) technology for remediation of TCA

    SciTech Connect

    Lavid, M.; Gulati, S.K.; Teytelboym, M.

    1994-12-31

    The Reductive Photo-Dechlorination (RPD) technology uses ultraviolet light in a reducing atmosphere to remove chlorine atoms from organo-chlorine waste streams at low to moderate temperatures. Because chlorinated organics are destroyed in a reducing environment, process products include valuable hydrocarbons and hydrogen chloride with no toxic oxygenated chlorocarbon by-products. The RPD process is designed specifically to treat volatile chlorinated wastes in the liquid or gaseous phases. Field applications include organic wastes produced from soil venting operations and those adsorbed on activated carbon. The process can also be used to pretreat gas streams entering catalytic oxidation systems, reducing chlorine content and hereby protecting the catalyst against poisoning. This paper focuses on photo-thermal remediation of 1,1,1-trichloroethane (TCA). It describes bench-scale experimental results, kinetic modeling predictions, and selected design parameters for a pilot-scale demonstration.

  8. Influence of cycling current and power profiles on the cycle life of lead/acid batteries

    NASA Astrophysics Data System (ADS)

    Papazov, G.; Pavlov, D.

    Batteries are assembled with positive plates of the novel strap grid tubular (SGTP) design described in a previous paper [1]. These batteries are subjected to four tests: (i) Peukert dependence determinations; (ii) classical galvanostatic cycling (5 h charge and 1 h discharge); (iii) EV-SFUDS, and (iv) EV-ECE-15 cycling tests. It has been established that the Peukert dependence curve of SGTP batteries is very close in profile to that for SLI batteries. This guarantees SGTP's batteries high power performance. These batteries endure over 950 cycles on galvanostatic cycling. When cycled according to the SFUDS power profile under a current load of 320 A/kg positive active mass during the 15th SFUDS step, SGTP batteries exhibit a cycle life of 350-450 cycles. If the current density during the 15th step is 190 A/kg PAM, the batteries endure over 600 charge/discharge cycles. The life of positive SGT plates is limited by power loss, but not by capacity. Similar results have also been obtained from ECE-15 cycle-life tests. On cycling SGTP batteries with a current load of 210 A/kg PAM during the 23rd ECE-15 step (the step during which maximum power output is demanded from the battery), they endure between 550 and 650 charge/discharge cycles. A summary of the test results obtained for two batches of experimental batteries indicates that there is a direct dependence between the SGTP battery cycle life and the maximum current density on discharge. Increasing the discharge current density decreases the battery life. It has also been established that the capacity on SFUDS (ECE-15) discharge declines gradually on cycling in favour of the residual galvanostatic capacity at 5 h rate of discharge (100% depth-of-discharge) which increases. This implies that two types of structures are formed in the positive plates on cycling: the first type ensuring high power output and the second type yielding low power but long cycle life. The higher the power delivered by the positive plate, the

  9. Closed cycle ion exchange method for regenerating acids, bases and salts

    DOEpatents

    Dreyfuss, Robert M.

    1976-01-01

    A method for conducting a chemical reaction in acidic, basic, or neutral solution as required and then regenerating the acid, base, or salt by means of ion exchange in a closed cycle reaction sequence which comprises contacting the spent acid, base, or salt with an ion exchanger, preferably a synthetic organic ion-exchange resin, so selected that the counter ions thereof are ions also produced as a by-product in the closed reaction cycle, and then regenerating the spent ion exchanger by contact with the by-product counter ions. The method is particularly applicable to closed cycle processes for the thermochemical production of hydrogen.

  10. A new electrolyte formulation for low cost cycling lead acid batteries

    NASA Astrophysics Data System (ADS)

    Torcheux, L.; Lailler, P.

    This paper is devoted to the development of a new lead acid battery electrolyte formulation for cycling applications, especially for renewable energy markets in developing countries. These emerging markets, such as solar home systems, require lead acid batteries at very low prices and improved performances compared to automotive batteries produced locally. The new acid formulation developed is a mixture of sulphuric acid, liquid colloidal silica and other additives including phosphoric acid. The colloidal silica is used at a low concentration in order to decrease the acid stratification process during cycling at high depth of discharge. Phosphoric acid is used for the improvement of the textural evolution of the positive active material during cycling. After a description of the markets and of the additives used in the new acid formulation, this paper presents the results obtained with normalised photovoltaic cycle testing on low cost automotive batteries modified by the new electrolyte formulation. It is shown that the cycling life of such batteries is much increased in the presence of the new formulation. These results are explained by the improved evolution of positive active mass softening parameters (specific surface and β-PbO 2 crystallite size) and also by a more homogeneous sulphating process on both plates.

  11. Stoichiometry of Reducing Equivalents and Splitting of Water in the Citric Acid Cycle.

    ERIC Educational Resources Information Center

    Madeira, Vitor M. C.

    1988-01-01

    Presents a solution to the problem of finding the source of extra reducing equivalents, and accomplishing the stoichiometry of glucose oxidation reactions. Discusses the citric acid cycle and glycolysis. (CW)

  12. Hydrogen Storage in the Carbon Dioxide - Formic Acid Cycle.

    PubMed

    Fink, Cornel; Montandon-Clerc, Mickael; Laurenczy, Gabor

    2015-01-01

    This year Mankind will release about 39 Gt carbon dioxide into the earth's atmosphere, where it acts as a greenhouse gas. The chemical transformation of carbon dioxide into useful products becomes increasingly important, as the CO(2) concentration in the atmosphere has reached 400 ppm. One approach to contribute to the decrease of this hazardous emission is to recycle CO(2), for example reducing it to formic acid. The hydrogenation of CO(2) can be achieved with a series of catalysts under basic and acidic conditions, in wide variety of solvents. To realize a hydrogen-based charge-discharge device ('hydrogen battery'), one also needs efficient catalysts for the reverse reaction, the dehydrogenation of formic acid. Despite of the fact that the overwhelming majority of these reactions are carried out using precious metals-based catalysts (mainly Ru), we review here developments for catalytic hydrogen evolution from formic acid with iron-based complexes. PMID:26842324

  13. Elimination and replenishment of tricarboxylic acid-cycle intermediates in myocardium.

    PubMed Central

    Nuutinen, E M; Peuhkurinen, K J; Pietiläinen, E P; Hiltunen, J K; Hassinen, I E

    1981-01-01

    1. The contribution of Co2 fixation to the anaplerotic mechanisms in the myocardium was investigated in isolated perfused rat hearts. 2. K+-induced arrest of the heart was used to elicit a transition in the concentrations of the intermediates of the tricarboxylic acid cycle. 3. Incorporation of 14C from [14]bicarbonate into tricarboxylic acid-cycle intermediates was measured and the rates of the reactions of the cycle were estimated by means of a linear optimization program which solves the differential equations describing a simulation model of the tricarboxylic acid cycle and related reactions. 4. The results showed that the rate of CO2 fixation is dependent on the metabolic state of the myocardium. Upon a sudden diminution of cellular ATP consumption, the pool size of the tricarboxylic acid-cycle metabolites increased and the rate of label incorporation from [14C]bicarbonate into the cycle metabolites increased simultaneously. The computer model was necessary to separate the rapid equilibration between bicarbonate and some metabolites from the potentially anaplerotic reactions. The main route of anaplerosis during metabolite accumulation was through malate + oxaloacetate. Under steady-state conditions there was a constant net outward flow from the tricarboxylic acid cycle via the malate + oxaloacetate pool, with a concomitant anaplerotic flow from metabolites forming succinyl-CoA (3-carboxypropionyl-CoA). PMID:6796067

  14. Effects of the oestrous cycle on the metabolism of arachidonic acid in rat isolated lung.

    PubMed Central

    Bakhle, Y S; Zakrzewski, J T

    1982-01-01

    1. The metabolism of exogenous arachidonic acid perfused through the pulmonary circulation was investigated in lungs taken from rats at different stages of the oestrous cycle. 2. Following perfusion with [14C]arachidonic acid there was more radioactivity associated with cyclo-oxygenase products in general at pro-oestrus than at any other stage of the cycle. 3. Production of 6-oxo-prostaglandin F1 alpha and hence of prostacyclin (PGI2) was also highest at pro-oestrus. 4. Production of thromboxane B2 was highest at pro-oestrus although it was never greater than PGI2 production at any stage. 5. Radioactivity retained in lung tissue was mostly present in phospholipid and free fatty acid fractions with the distribution at pro-oestrus being different from the other stages. 6. Following perfusion with [14C]oleic acid (which is not a substrate for cyclooxygenase), variations in the distribution of label in radioactivity in lung were also observed. However, these were not related to the stages of the oestrous cycle in the same way as those associated with arachidonic acid. 7. We conclude that both pathways of arachidonic acid metabolism in lung--oxidation via cyclo-oxygenase and incorporation into phospholipid - are affected by the progress of the oestrous cycle. 8. Altered arachidonate metabolism appeared to be associated chiefly with pro-oestrus and may be linked to those hormones involved in this stage of the oestrous cycle. PMID:6809935

  15. Evaluation results of xTCA equipment for HEP experiments at CERN

    NASA Astrophysics Data System (ADS)

    Di Cosmo, M.; Bobillier, V.; Haas, S.; Joos, M.; Mico, S.; Vasey, F.; Vichoudis, P.

    2013-12-01

    The MicroTCA and AdvancedTCA industry standards are candidate modular electronic platforms for the upgrade of the current generation of high energy physics experiments. The PH-ESE group at CERN launched in 2011 the xTCA evaluation project with the aim of performing technical evaluations and eventually providing support for commercially available components. Different devices from different vendors have been acquired, evaluated and interoperability tests have been performed. This paper presents the test procedures and facilities that have been developed and focuses on the evaluation results including electrical, thermal and interoperability aspects.

  16. A Functional Tricarboxylic Acid Cycle Operates during Growth of Bordetella pertussis on Amino Acid Mixtures as Sole Carbon Substrates

    PubMed Central

    Garnier, Dominique; Speck, Denis

    2015-01-01

    It has been claimed that citrate synthase, aconitase and isocitrate dehydrogenase activities are non-functional in Bordetella pertussis and that this might explain why this bacterium’s growth is sometimes associated with accumulation of polyhydroxybutyrate (PHB) and/or free fatty acids. However, the sequenced genome includes the entire citric acid pathway genes. Furthermore, these genes were expressed and the corresponding enzyme activities detected at high levels for the pathway when grown on a defined medium imitating the amino acid content of complex media often used for growth of this pathogenic microorganism. In addition, no significant PHB or fatty acids could be detected. Analysis of the carbon balance and stoichiometric flux analysis based on specific rates of amino acid consumption, and estimated biomass requirements coherent with the observed growth rate, clearly indicate that a fully functional tricarboxylic acid cycle operates in contrast to previous reports. PMID:26684737

  17. Interactive enhancements of ascorbic acid and iron in hydroxyl radical generation in quinone redox cycling.

    PubMed

    Li, Yi; Zhu, Tong; Zhao, Jincai; Xu, Bingye

    2012-09-18

    Quinones are toxicological substances in inhalable particulate matter (PM). The mechanisms by which quinones cause hazardous effects can be complex. Quinones are highly active redox molecules that can go through a redox cycle with their semiquinone radicals, leading to formation of reactive oxygen species. Electron spin resonance spectra have been reported for semiquinone radicals in PM, indicating the importance of ascorbic acid and iron in quinone redox cycling. However, these findings are insufficient for understanding the toxicity associated with quinone exposure. Herein, we investigated the interactions among anthraquinone (AQ), ascorbic acid, and iron in hydroxyl radical (·OH) generation through the AQ redox cycling process in a physiological buffer. We measured ·OH concentration and analyzed the free radical process. Our results showed that AQ, ascorbic acid, and iron have synergistic effects on ·OH generation in quinone redox cycling; i.e., ascorbyl radical oxidized AQ to semiquinone radical and started the redox cycling, iron accelerated this oxidation and enhanced ·OH generation through Fenton reactions, while ascorbic acid and AQ could help iron to release from quartz surface and enhance its bioavailability. Our findings provide direct evidence for the redox cycling hypothesis about airborne particle surface quinone in lung fluid. PMID:22891791

  18. Photoreduction fuels biogeochemical cycling of iron in Spain's acid rivers

    USGS Publications Warehouse

    Gammons, C.H.; Nimick, D.A.; Parker, S.R.; Snyder, D.M.; McCleskey, R.B.; Amils, R.; Poulson, S.R.

    2008-01-01

    A number of investigations have shown that photoreduction of Fe(III) causes midday accumulations of dissolved Fe(II) in rivers and lakes, leading to large diel (24-h) fluctuations in the concentration and speciation of total dissolved iron. Less well appreciated is the importance of photoreduction in providing chemical energy for bacteria to thrive in low pH waters. Diel variations in water chemistry from the highly acidic (pH 2.3 to 3.1) Ri??o Tinto, Ri??o Odiel, and Ri??o Agrio of southwestern Spain (Iberian Pyrite Belt) resulted in daytime increases in Fe(II) concentration of 15 to 66????M at four diel sampling locations. Dissolved Fe(II) concentrations increased with solar radiation, and one of the stream sites showed an antithetic relationship between dissolved Fe(II) and Fe(III) concentrations; both results are consistent with photoreduction. The diel data were used to estimate rates of microbially catalyzed Fe(II) oxidation (1 to 3??nmol L- 1 s- 1) and maximum rates of Fe(III) photoreduction (1.7 to 4.3??nmol L- 1 s- 1). Bioenergetic calculations indicate that the latter rates are sufficient to build up a population of Fe-oxidizing bacteria to the levels observed in the Ri??o Tinto in about 30??days. We conclude that photoreduction plays an important role in the bioenergetics of the bacterial communities of these acidic rivers, which have previously been shown to be dominated by autotrophic Fe(II)-oxidizers such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans. Given the possibility of the previous existence of acidic, Fe(III)-rich water on Mars, photoreduction may be an important process on other planets, a fact that could have implications to astrobiological research. ?? 2008 Elsevier B.V. All rights reserved.

  19. An alternative mechanism for guanidinoacetic acid to affect methylation cycle.

    PubMed

    Ostojic, Sergej M

    2014-12-01

    Guanidinoacetic acid (also known as glycocyamine; GAA) is an endogenous substance which occurs in humans and plays a central role in the biosynthesis of creatine. The formation of creatine from GAA consumes methyl groups, and increases production of homocysteine. GAA may have the potential to stimulate insulin secretion. Insulin reduces plasma homocysteine and raises methyl group supply. It is possible that the ability of GAA to trigger the insulin secretion modulates methyl group metabolism, and comparatively counterbalance for the direct effect of GAA on increased methylation demand. Possible insulinotropic effect of GAA may contribute to total in vivo methylation demand during biotransformation. PMID:25468046

  20. Nonfunctional tricarboxylic acid cycle and the mechanism of glutamate biosynthesis in Acetobacter suboxydans.

    PubMed

    Greenfield, S; Claus, G W

    1972-12-01

    Acetobacter suboxydans does not contain an active tricarboxylic acid cycle, yet two pathways have been suggested for glutamate synthesis from acetate catalyzed by cell extracts: a partial tricarboxylic acid cycle following an initial condensation of oxalacetate and acetyl coenzyme A. and the citramalate-mesaconate pathway following an initial condensation of pyruvate and acetyl coenzyme A. To determine which pathway functions in growing cells, acetate-1-(14)C was added to a culture growing in minimal medium. After growth had ceased, cells were recovered and fractionated. Radioactive glutamate was isolated from the cellular protein fraction, and the position of the radioactive label was determined. Decarboxylation of the C5 carbon removed 100% of the radioactivity found in the purified glutamate fraction. These experiments establish that growing cells synthesize glutamate via a partial tricarboxylic acid cycle. Aspartate isolated from these hydrolysates was not radioactive, thus providing further evidence for the lack of a complete tricarboxylic acid cycle. When cell extracts were analyzed, activity of all tricarboxylic acid cycle enzymes, except succinate dehydrogenase, was demonstrated. PMID:4640504

  1. Halogenated methanesulfonic acids: A new class of organic micropollutants in the water cycle.

    PubMed

    Zahn, Daniel; Frömel, Tobias; Knepper, Thomas P

    2016-09-15

    Mobile and persistent organic micropollutants may impact raw and drinking waters and are thus of concern for human health. To identify such possible substances of concern nineteen water samples from five European countries (France, Switzerland, The Netherlands, Spain and Germany) and different compartments of the water cycle (urban effluent, surface water, ground water and drinking water) were enriched with mixed-mode solid phase extraction. Hydrophilic interaction liquid chromatography - high resolution mass spectrometry non-target screening of these samples led to the detection and structural elucidation of seven novel organic micropollutants. One structure could already be confirmed by a reference standard (trifluoromethanesulfonic acid) and six were tentatively identified based on experimental evidence (chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid and bromochloromethanesulfonic acid). Approximated concentrations for these substances show that trifluoromethanesulfonic acid, a chemical registered under the European Union regulation REACH with a production volume of more than 100 t/a, is able to spread along the water cycle and may be present in concentrations up to the μg/L range. Chlorinated and brominated methanesulfonic acids were predominantly detected together which indicates a common source and first experimental evidence points towards water disinfection as a potential origin. Halogenated methanesulfonic acids were detected in drinking waters and thus may be new substances of concern. PMID:27267477

  2. ANALYSIS AND SIMULATION OF RECYCLE SO2-LIME SLURRY IN TCA (TURBULENT CONTACT ABSORBER) SCRUBBER SYSTEM

    EPA Science Inventory

    The report gives results of an analysis of flue gas desulfurization by a turbulent contact absorber (TCA) employing lime slurry, including the development of performance equations for the scrubber-hold tank recycle system. Performance characteristics investigated include pressure...

  3. Control of gag-pol gene expression in the Candida albicans retrotransposon Tca2

    PubMed Central

    Forbes, Elaine M; Nieduszynska, Siân R; Brunton, Fiona K; Gibson, Joanne; Glover, L Anne; Stansfield, Ian

    2007-01-01

    Background In the C. albicans retrotransposon Tca2, the gag and pol ORFs are separated by a UGA stop codon, 3' of which is a potential RNA pseudoknot. It is unclear how the Tca2 gag UGA codon is bypassed to allow pol expression. However, in other retroelements, translational readthrough of the gag stop codon can be directed by its flanking sequence, including a 3' pseudoknot. Results The hypothesis was tested that in Tca2, gag stop codon flanking sequences direct translational readthrough and synthesis of a gag-pol fusion protein. Sequence from the Tca2 gag-UGA-pol junction (300 nt) was inserted between fused lacZ and luciferase (luc) genes in a Saccharomyces cerevisiae dual reporter construct. Although downstream of UGA, luc was expressed, but its expression was unaffected by inserting additional stop codons at the 3' end of lacZ. Luc expression was instead being driven by a previously unknown minor promoter activity within the gag-pol junction region. Evidence together indicated that junction sequence alone cannot direct UGA readthrough. Using reporter genes in C. albicans, the activities of this gag-pol junction promoter and the Tca2 long terminal repeat (LTR) promoter were compared. Of the two promoters, only the LTR promoter was induced by heat-shock, which also triggers retrotransposition. Tca2 pol protein, epitope-tagged in C. albicans to allow detection, was also heat-shock induced, indicating that pol proteins were expressed from a gag-UGA-pol RNA. Conclusion This is the first demonstration that the LTR promoter directs Tca2 pol protein expression, and that pol proteins are translated from a gag-pol RNA, which thus requires a mechanism for stop codon bypass. However, in contrast to most other retroelement and viral readthrough signals, immediate gag UGA-flanking sequences were insufficient to direct stop readthrough in S. cerevisiae, indicating non-canonical mechanisms direct gag UGA bypass in Tca2. PMID:17961216

  4. Development of a cellular biosensor for the detection of 2,4,6-trichloroanisole (TCA).

    PubMed

    Varelas, Vassileios; Sanvicens, Nuria; M-Pilar-Marco; Kintzios, Spiridon

    2011-05-15

    2,4,6-trichloroanisole (TCA) is a microbial metabolite formed from chlorophenols through the activity of several natural fungal strains present on the cork oak bark. TCA is the primary compound responsible for the mousty/mould off-odour known as "cork taint" present in cork stoppers, wine, water and alcoholic beverages. Chromatographic and electrochemical methods are currently used for the determination of TCA, however its detection at low concentrations remains a technical challenge. The aim of this study was the development of a rapid novel biosensor system based on the Bioelectric Recognition Assay (BERA). The sensor measured the electric response of cultured membrane-engineered fibroblast cells suspended in an alginate gel matrix due to the change of their membrane potential in the presence of the analyte. Membrane-engineered cells were prepared by osmotic insertion of 0.5 μg/l of specific TCA antibodies into the membrane of the cells. The BERA-based sensor was able to detect TCA in a few minutes (3-5 min) at extremely low concentrations (10(-1)ppt), thus demonstrating higher sensitivity than the human sensory threshold. In addition, the assay was quite selective against other haloanisoles and halophenols structurally related to or co-occurring with TCA. Finally the sensor was tested against real white wine samples from cork soaks. At this real test, the BERA sensor was able to detect TCA from cork soaks rapidly (3-5 min) at very low concentrations (1.02-12 ng/l), covering the whole range for the detection threshold for wines (1.4-10 ng/l). Therefore, this novel biosensor offers new perspectives for ultra-rapid, ultra-sensitive and low-cost monitoring of TCA presence in cork and wine and possibly also other food commodities. PMID:21482306

  5. The effects of climate change on the nitrogen cycle and acid deposition

    SciTech Connect

    Penner, J.E.; Walton, J.J. ); Graboske, B.C. )

    1990-09-01

    Increases in greenhouse gases are expected to lead to a number of changes to the atmosphere which may impact regional and global chemical cycles. With the increasing awareness of climate change and the possibility of global chemical changes to the atmosphere, it becomes important to ask whether these changes to global climate and chemical cycles might benefit or hinder control programs aimed at reducing acid deposition. In the following, we review several possible changes to climate that may be expected to impact the global cycle of reactive nitrogen. We then use our global model of the reactive nitrogen cycle to estimate the effects of several of the more important changes on the continental-scale deposition of nitric acid. 7 refs., 1 tab.

  6. NHI-Acid Concentration Membranes -- Membrane Recommendations for the S-I Cycle

    SciTech Connect

    Frederick F Stewart

    2007-03-01

    Scope: The purpose of this draft report is to make recommendations concerning the applicability of specific membrane materials for acid concentration processes to the Sulfur-Iodine (S-I) thermochemical cycle integrated laboratory scale (ILS) demonstration. Introduction Acid concentration membrane processes have been studied for possible inclusion in the Sulfur-Iodine integrated laboratory scale (S-I ILS) demonstration. The need for this technology is driven by the chemical processes required for economical water splitting using the S-I cycle. Of the chemical processes inherent to the S-I cycle that have been identified as targets for deployment of membrane technology, three have been studied during the past three fiscal years as a part of the DOE Nuclear Hydrogen Initiative. First, the ability to concentrate hydriodic acid (HI) and iodine mixtures was sought as a method for aiding in the isolation of HI away from water and iodine. Isolated HI would then be delivered to the HI decomposition process for liberation of product hydrogen. Second, an extension of this technology to sulfuric acid was proposed to benefit sulfuric acid decomposition recycle. Third, decomposition of HI to form hydrogen is equilibrium limited. Removal of hydrogen, utilizing Le Chatelier’s principle, will increase to overall conversion and thus increasing the efficiency of the S-I cycle.

  7. SURFACE DEGRADATION OF COMPOSITE RESINS BY ACIDIC MEDICINES AND pH-CYCLING

    PubMed Central

    Valinoti, Ana Carolina; Neves, Beatriz Gonçalves; da Silva, Eduardo Moreira; Maia, Lucianne Cople

    2008-01-01

    This study evaluated the effects of acidic medicines (Dimetapp® and Claritin®), under pH-cycling conditions, on the surface degradation of four composite resins (microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped specimens (Ø = 5.0 mm / thickness = 2.0 mm) of each composite were randomly assigned to 3 groups (n = 10): a control and two experimental groups, according to the acidic medicines evaluated. The specimens were finished and polished with aluminum oxide discs, and the surface roughness was measured by using a profilometer. After the specimens were submitted to a pH-cycling regimen and immersion in acidic medicines for 12 days, the surface roughness was measured again. Two specimens for each material and group were analyzed by scanning electron microscopy (SEM) before and after pH-cycling. Data were analyzed by the Student's-t test, ANOVA, Duncan's multiple range test and paired t-test (α=0.05). Significant increase in roughness was found only for TPH in the control group and TPH and Supreme immersed in Claritin® (p<0.05). SEM analyses showed that the 4 composite resins underwent erosion and surface degradation after being subjected to the experimental conditions. In conclusion, although the roughness was slightly affected, the pH-cycling and acidic medicines caused surface degradation of the composite resins evaluated. Titratable acidity seemed to play a more crucial role on surface degradation of composite resins than pH. PMID:19089257

  8. TERATOGENIC ACTIVITY OF TRICHLOROACETIC ACID

    EPA Science Inventory

    Trichloroacetic acid (TCA)is a by-product of the chlorine disinfection of water containing natural organic material. It is detectable finished drinking water at levels comparable to the trihalomethanes (30-60). TCA is also formed in vivo after ingestion of hypochlorite and has be...

  9. Results of chopper-controlled discharge life cycling studies on lead acid batteries

    NASA Technical Reports Server (NTRS)

    Ewashinka, J. G.; Sidik, S. M.

    1982-01-01

    A group of 108 state of the art nominally 6 volt lead acid batteries were tested in a program of one charge/discharge cycle per day for over two years or to ultimate battery failure. The primary objective was to determine battery cycle life as a function of depth of discharge (25 to 75 percent), chopper frequency (100 to 1000 Hz), duty cycle (25 to 87.5 percent), and average discharge current (20 to 260 A). The secondary objective was to determine the types of battery failure modes, if any, were due to the above parameters. The four parameters above were incorporated in a statistically designed test program.

  10. Chopper-controlled discharge life cycling studies on lead-acid batteries

    NASA Technical Reports Server (NTRS)

    Kraml, J. J.; Ames, E. P.

    1982-01-01

    State-of-the-art 6 volt lead-acid golf car batteries were tested. A daily charge/discharge cycling to failure points under various chopper controlled pulsed dc and continuous current load conditions was undertaken. The cycle life and failure modes were investigated for depth of discharge, average current chopper frequency, and chopper duty cycle. It is shown that battery life is primarily and inversely related to depth of discharge and discharge current. Failure mode is characterized by a gradual capacity loss with consistent evidence of cell element aging.

  11. Microbial Dissimilatory Sulfur Cycle in Acid Mine Water

    PubMed Central

    Tuttle, Jon H.; Dugan, Patrick R.; Macmillan, Carol B.; Randles, Chester I.

    1969-01-01

    Ferric, sulfate, and hydrogen ions are produced from pyritic minerals associated with coal as a result of autotrophic bacterial metabolism. Water carrying these ions accumulated behind a porous dam composed of wood dust originating at a log-cutting mill. As water seeped through the porous dam, it was enriched in organic nutrients which then supported growth and metabolism of heterotrophic bacteria in the water downstream from the dam. The heterotrophic microflora within and below the sawdust dam included dissimilatory sulfate-reducing anaerobic bacteria which reduce sulfate to sulfide. The sulfide produced caused the chemical reduction of ferric to ferrous ion, and black FeS precipitate was deposited on the pond bottom. A net increase in the pH of the lower pond water was observed when compared to the upper pond water. Microbial activity in the wood dust was demonstrated, and a sequence of cellulose degradation processes was inferred on the basis of sugar accumulation in mixed cultures in the laboratory, ultimately yielding fermentation products which serve as nutrients for sulfate-reducing bacteria. Some of the microorganisms were isolated and characterized. The biochemical and growth characteristics of pure culture isolates were generally consistent with observed reactions in the acidic environment, with the exception of sulfate-reducing bacteria. Mixed cultures which contained sulfate-reducing bacteria reduced sulfate at pH 3.0 in the laboratory with sawdust as the only nutrient. Pure cultures of sulfate-reducing bacteria isolated from the mixed cultures did not reduce sulfate below pH 5.5. PMID:5773013

  12. Glyoxylate cycle and metabolism of organic acids in the scutellum of barley seeds during germination.

    PubMed

    Ma, Zhenguo; Marsolais, Frédéric; Bernards, Mark A; Sumarah, Mark W; Bykova, Natalia V; Igamberdiev, Abir U

    2016-07-01

    During the developmental processes from dry seeds to seedling establishment, the glyoxylate cycle becomes active in the mobilization of stored oils in the scutellum of barley (Hordeum vulgare L.) seeds, as indicated by the activities of isocitrate lyase and malate synthase. The succinate produced is converted to carbohydrates via phosphoenolpyruvate carboxykinase and to amino acids via aminotransferases, while free organic acids may participate in acidifying the endosperm tissue, releasing stored starch into metabolism. The abundant organic acid in the scutellum was citrate, while malate concentration declined during the first three days of germination, and succinate concentration was low both in scutellum and endosperm. Malate was more abundant in endosperm tissue during the first three days of germination; before citrate became predominant, indicating that malate may be the main acid acidifying the endosperm. The operation of the glyoxylate cycle coincided with an increase in the ATP/ADP ratio, a buildup of H2O2 and changes in the redox state of ascorbate and glutathione. It is concluded that operation of the glyoxylate cycle in the scutellum of cereals may be important not only for conversion of fatty acids to carbohydrates, but also for the acidification of endosperm and amino acid synthesis. PMID:27181945

  13. Acetaminophen Toxicity and 5-Oxoproline (Pyroglutamic Acid): A Tale of Two Cycles, One an ATP-Depleting Futile Cycle and the Other a Useful Cycle

    PubMed Central

    2014-01-01

    Summary The acquired form of 5-oxoproline (pyroglutamic acid) metabolic acidosis was first described in 1989 and its relationship to chronic acetaminophen ingestion was proposed the next year. Since then, this cause of chronic anion gap metabolic acidosis has been increasingly recognized. Many cases go unrecognized because an assay for 5-oxoproline is not widely available. Most cases occur in malnourished, chronically ill women with a history of chronic acetaminophen ingestion. Acetaminophen levels are very rarely in the toxic range; rather, they are usually therapeutic or low. The disorder generally resolves with cessation of acetaminophen and administration of intravenous fluids. Methionine or N-acetyl cysteine may accelerate resolution and methionine is protective in a rodent model. The disorder has been attributed to glutathione depletion and activation of a key enzyme in the γ-glutamyl cycle. However, the specific metabolic derangements that cause the 5-oxoproline accumulation remain unclear. An ATP-depleting futile 5-oxoproline cycle can explain the accumulation of 5-oxoproline after chronic acetaminophen ingestion. This cycle is activated by the depletion of both glutathione and cysteine. This explanation contributes to our understanding of acetaminophen-induced 5-oxoproline metabolic acidosis and the beneficial role of N-acetyl cysteine therapy. The ATP-depleting futile 5-oxoproline cycle may also play a role in the energy depletions that occur in other acetaminophen-related toxic syndromes. PMID:24235282

  14. Thermochemical cycles

    NASA Technical Reports Server (NTRS)

    Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

    1975-01-01

    The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

  15. Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids.

    PubMed

    Ferrebee, Courtney B; Dawson, Paul A

    2015-03-01

    The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5). PMID:26579438

  16. Apoptosis and modulation of cell cycle control by bile acids in human leukemia T cells.

    PubMed

    Fimognari, Carmela; Lenzi, Monia; Cantelli-Forti, Giorgio; Hrelia, Patrizia

    2009-08-01

    Depending on the nature of chemical structures, different bile acids exhibit distinct biological effects. Their therapeutic efficacy has been widely demonstrated in various liver diseases, suggesting that they might protect hepatocytes against common mechanisms of liver damage. Although it has been shown to prevent apoptotic cell death in certain cell lines, bile acids significantly inhibited cell growth and induced apoptosis in cancer cells. To better understand the pharmacological potential of bile acids in cancer cells, we investigated and compared the effects of deoxycholic acid (DCA), ursodeoxycholic acid (UDCA), and their taurine-derivatives [taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA), respectively] on the induction of apoptosis and inhibition of cell proliferation of a human T leukemia cell line (Jurkat cells). All the bile acids tested induced a delay in cell cycle progression. Moreover, DCA markedly increased the fraction of apoptotic cells. The effects of TDCA, UDCA, and TUDCA were different from those observed for DCA. Their primary effect was the induction of necrosis. These distinctive features suggest that the hydrophobic properties of DCA play a role in its cytotoxic potential and indicate that it is possible to create new drugs useful for cancer therapy from bile acid derivatives as lead compounds. PMID:19723064

  17. Gas-aerosol cycling of ammonia and nitric acid in The Netherlands

    NASA Astrophysics Data System (ADS)

    Roelofs, Geert-Jan; Derksen, Jeroen

    2010-05-01

    Atmospheric ammonia and nitric acid are present over NW Europe in large abundance. Observations made during the IMPACT measurement campaign (May 2008, Cabauw, The Netherlands) show a pronounced diurnal cycle of aerosol ammonium and nitrate on relatively dry days. Simultaneously, AERONET data show a distinct diurnal cycle in aerosol optical thickness (AOT). We used a global aerosol-climate model (ECHAM5-HAM) and a detailed aerosol-cloud column model to help analyse the observations from this period. The study shows that the diurnal cycle in AOT is partly associated with particle number concentration, with distinct peaks in the morning and evening. More important is relative humidity (RH). RH maximizes in the night and early morning, decreases during the morning and increases again in the evening. The particle wet radius, and therefore AOT, changes accordingly. In addition, the RH variability also influences chemistry associated with ammonia and nitric acid (formation of ammonium nitrate, dissolution in aerosol water), resulting in the observed diurnal cycle of aerosol ammonium and nitrate. The additional aerosol matter increases the hygroscopicity of the particles, and this leads to further swelling by water vapor condensation and a further increase of AOT. During the day, as RH decreases and the particles shrink, aerosol ammonium and nitrate are again partly expelled to the gas phase. This behaviour contributes significantly to the observed diurnal cycle in AOT, and it illustrates the complexity of using AOT as a proxy for aerosol concentrations in aerosol climate studies in the case of heavily polluted areas.

  18. Temperature effects on sealed lead acid batteries and charging techniques to prolong cycle life.

    SciTech Connect

    Hutchinson, Ronda

    2004-06-01

    Sealed lead acid cells are used in many projects in Sandia National Laboratories Department 2660 Telemetry and Instrumentation systems. The importance of these cells in battery packs for powering electronics to remotely conduct tests is significant. Since many tests are carried out in flight or launched, temperature is a major factor. It is also important that the battery packs are properly charged so that the test is completed before the pack cannot supply sufficient power. Department 2665 conducted research and studies to determine the effects of temperature on cycle time as well as charging techniques to maximize cycle life and cycle times on sealed lead acid cells. The studies proved that both temperature and charging techniques are very important for battery life to support successful field testing and expensive flight and launched tests. This report demonstrates the effects of temperature on cycle time for SLA cells as well as proper charging techniques to get the most life and cycle time out of SLA cells in battery packs.

  19. An Assessment of the Efficacy and Safety of CROSS Technique with 100% TCA in the Management of Ice Pick Acne Scars

    PubMed Central

    Bhardwaj, Deepali; Khunger, Niti

    2010-01-01

    Background: Chemical reconstruction of skin scars (CROSS) is a technique using high concentrations of trichloroacetic acid (TCA) focally on atrophic acne scars to induce inflammation followed by collagenisation. This can lead to reduction in the appearance of scars and cosmetic improvement. Aims: The aim of this pilot study is to investigate the safety of the CROSS technique, using 100% TCA, for atrophic ice pick acne scars. Settings and Design: Open prospective study. Material and Methods: Twelve patients with predominant atrophic ice pick post acne scars were treated with the CROSS technique, using 100% TCA, applied with a wooden toothpick, at two weekly intervals for four sittings. Efficacy was assessed on the basis of the physician’s clinical assessment, photographic evaluation at each sitting and patient’s feedback after the fourth treatment, and at the three-month and six-month follow-up period, after the last treatment. Results: More than 70% improvement was seen in eight out of ten patients evaluated and good results (50 – 70% improvement) were observed in the remaining two patients. No significant side effects were noted. Transient hypopigmentation and hyperpigmentation was observed in one patient each. Physician’s findings were in conformity with the patient’s assessment. Three months after the last treatment, one patient noted a decrease in improvement with no further improvement even at the six-month follow-up period. Conclusion: The CROSS technique with 100% TCA is a safe, efficacious, cost-effective and minimally invasive technique for the management of ice pick acne scars that are otherwise generally difficult to treat. In few patients the improvement may not be sustained, probably due to inadequate or delayed collagenisation. PMID:21031068

  20. [Glucose-fatty acids cycle in cobalt chloride-induced oxidative stress in rats].

    PubMed

    Kaliman, P A; Okhrimenko, S M

    2005-01-01

    It was found that the glucose-fatty acids cycle functioned under the oxidative stress, caused by injection of cobalt chloride solution in albino rats. This cycle promoted the adaptation of metabolism and rehabilitated the homeostasis under extreme conditions. Its functioning was regulated by prolonged (during 2-24 hours) rise in activity of amino acids catabolism enzymes (e.g. tyrosine aminotransferase, arginase) and activation of glyconeogenesis after the mobilisation of liver glycogen. This contributed to increase in glucose and free fatty acids contents in blood. The latter is additionally provided by lipid mobilisation under stress. Tyrosine aminotransferase activation occurred both on the transcription level and by enabling of other mechanisms, which probably concerned the stabilisation of this enzyme. Preliminary injection of alpha-tocopherol in vivo significantly decreased the rise in tyrosine aminotransferase and arginase activities and the rate of erythrocyte hemolysis but did not disable them in full. This made evident that in regulation of the glucose-fatty acids cycle not only active metabolites of oxygen but also Co ions were directly enabled. PMID:16335249

  1. Evaluation of a commercial AdvancedTCA board management controller solution (IPMC)

    NASA Astrophysics Data System (ADS)

    Mendez, J.; Bobillier, V.; Haas, S.; Joos, M.; Vasey, F.

    2016-02-01

    The MicroTCA (MTCA) and AdvancedTCA (ATCA) industry standards have been selected as the hardware platform for the upgrade of the electronic systems of some of the experiments at the Large Hadron Collider (LHC) . In this context, the electronics support group for experiments at CERN is running a project to perform technical evaluations of MTCA and ATCA equipment. As part of this activity, a commercial solution for an Intelligent Platform Management Controller (IPMC), an essential component of any ATCA blade design, is being evaluated. We validated the supported IPMC features, checked the interoperability and adapted the reference design for use on an existing ATCA carrier board.

  2. Suppression of tricarboxylic acid cycle in Escherichia coli exposed to sub-MICs of aminoglycosides.

    PubMed Central

    Cavallero, A; Eftimiadi, C; Radin, L; Schito, G C

    1990-01-01

    The metabolic activity of Escherichia coli ATCC 25922 challenged with sub-MICs of aminoglycosides was analyzed with a batch calorimeter. High-performance and gas-liquid chromatographic techniques were utilized to evaluate the concentrations of metabolic reactants, intermediates, and end products. The data reported indicate that aminoglycosides inhibit or delay bacterial catabolism of carboxylic acids, with the following relative degrees of activity: amikacin greater than gentamicin greater than sisomicin greater than netilmicin greater than kanamycin. The decrease in total biomass production was proportional to the degree of tricarboxylic acid cycle inhibition. PMID:2183717

  3. Effect on combined cycle efficiency of stack gas temperature constraints to avoid acid corrosion

    NASA Technical Reports Server (NTRS)

    Nainiger, J. J.

    1980-01-01

    To avoid condensation of sulfuric acid in the gas turbine exhaust when burning fuel oils contaning sulfur, the exhaust stack temperature and cold-end heat exchanger surfaces must be kept above the condensation temperature. Raising the exhaust stack temperature, however, results in lower combined cycle efficiency compared to that achievable by a combined cycle burning a sulfur-free fuel. The maximum difference in efficiency between the use of sulfur-free and fuels containing 0.8 percent sulfur is found to be less than one percentage point. The effect of using a ceramic thermal barrier coating (TBC) and a fuel containing sulfur is also evaluated. The combined-cycle efficiency gain using a TBC with a fuel containing sulfur compared to a sulfur-free fuel without TBC is 0.6 to 1.0 percentage points with air-cooled gas turbines and 1.6 to 1.8 percentage points with water-cooled gas turbines.

  4. The response of amino acid cycling to global change across multiple biomes: Feedbacks on soil nitrogen availability

    NASA Astrophysics Data System (ADS)

    Brzostek, E. R.; Finzi, A. C.

    2010-12-01

    The cycling of organic nitrogen (N) in soil links soil organic matter decomposition to ecosystem productivity. Amino acids are a key pool of organic N in the soil, whose cycling is sensitive to alterations in microbial demand for carbon and N. Further, the amino acids released from the breakdown of protein by proteolytic enzymes are an important source of N that supports terrestrial productivity. The objective of this study was to measure changes in amino acid cycling in response to experimental alterations of precipitation and temperature in twelve global change experiments during the 2009 growing season. The study sites ranged from arctic tundra to xeric grasslands. The treatments experimentally increased temperature, increased or decreased precipitation, or some combination of both factors. The response of amino acid cycling to temperature and precipitation manipulations tended to be site specific, but the responses could be placed into a common framework. Changes in soil moisture drove a large response in amino acid cycling. Precipitation augmentation in xeric and mesic sites increased both amino acid pool sizes and production. However, treatments that decreased precipitation drove decreases in amino acid cycling in xeric sites, but led to increases in amino acid cycling in more mesic sites. Across sites, the response to soil warming was horizon specific. Amino acid cycling in organic rich horizons responded positively to warming, while negative responses were exhibited in lower mineral soil horizons. The variable response likely reflects a higher availability of protein substrate to sustain high rates of proteolytic enzyme activity in organic rich horizons. Overall, these results suggest that soil moisture and the availability of protein substrate may be important factors that mediate the response of amino acid cycling to predicted increases in soil temperatures.

  5. Functionalised carboxylic acids in atmospheric particles: An annual cycle revealing seasonal trends and possible sources

    NASA Astrophysics Data System (ADS)

    Teich, Monique; van Pinxteren, Dominik; Herrmann, Hartmut

    2013-04-01

    Carboxylic acids represent a major fraction of the water soluble organic carbon (WSOC) in atmospheric particles. Among the particle phase carboxylic acids, straight-chain monocarboxylic acids (MCA) and dicarboxylic acids (DCA) with 2-10 carbon atoms have extensively been studied in the past. However, only a few studies exist dealing with functionalised carboxylic acids, i.e. having additional hydroxyl-, oxo- or nitro-groups. Regarding atmospheric chemistry, these functionalised carboxylic acids are of particular interest as they are supposed to be formed during atmospheric oxidation processes, e.g. through radical reactions. Therefore they can provide insights into the tropospheric multiphase chemistry. During this work 28 carboxylic acids (4 functionalised aliphatic MCAs, 5 aromatic MCAs, 3 nitroaromatic MCAs, 6 aliphatic DCAs, 6 functionalised aliphatic DCAs, 4 aromatic DCAs) were quantitatively determined in 256 filter samples taken at the rural research station Melpitz (Saxony, Germany) with a PM10 Digitel DHA-80 filter sampler. All samples were taken in 2010 covering a whole annual cycle. The resulting dataset was examined for a possible seasonal dependency of the acid concentrations. Furthermore the influence of the air mass origin on the acid concentrations was studied based on a simple two-sector classification (western or eastern sector) using a back trajectory analysis. Regarding the annual average, adipic acid was found to be the most abundant compound with a mean concentration of 7.8 ng m-3 followed by 4-oxopimelic acid with 6.1 ng m-3. The sum of all acid concentrations showed two maxima during the seasonal cycle; one in summer and one in winter, whereas the highest overall acid concentrations were found in summer. In general the target acids could be divided into two different groups, where one group has its maximum concentration in summer and the other group during winter. The first group contains all investigated aliphatic mono- and dicarboxylic

  6. Anaplerotic Accumulation of Tricarboxylic Acid Cycle Intermediates as Well as Changes in Other Key Metabolites During Heterotopic Ossification

    PubMed Central

    Davis, Eleanor L.; Salisbury, Elizabeth A.; Olmsted‐Davis, Elizabeth

    2015-01-01

    ABSTRACT Heterotopic ossification (HO) is the de novo formation of bone that occurs in soft tissue, through recruitment, expansion, and differentiation of multiple cells types including transient brown adipocytes, osteoblasts, chondrocytes, mast cells, and platelets to name a few. Much evidence is accumulating that suggests changes in metabolism may be required to accomplish this bone formation. Recent work using a mouse model of heterotopic bone formation reliant on delivery of adenovirus‐transduced cells expressing low levels of BMP2 showed the immediate expansion of a unique brown adipocyte‐like cell. These cells are undergoing robust uncoupled oxidative phosphorylation to a level such that oxygen in the microenvironment is dramatically lowered creating areas of hypoxia. It is unclear how these oxygen changes ultimately affect metabolism and bone formation. To identify the processes and changes occurring over the course of bone formation, HO was established in the mice, and tissues isolated at early and late times were subjected to a global metabolomic screen. Results show that there are significant changes in both glucose levels, as well as TCA cycle intermediates. Additionally, metabolites necessary for oxidation of stored lipids were also found to be significantly elevated. The complete results of this screen are presented here, and provide a unique picture of the metabolic changes occurring during heterotopic bone formation. J. Cell. Biochem. 117: 1044–1053, 2016. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc. PMID:26627193

  7. Acid-Tolerant Sulfate-Reducing Bacteria Play a Major Role in Iron Cycling in Acidic Iron Rich Sediments

    NASA Astrophysics Data System (ADS)

    Enright, K. A.; Moreau, J. W.

    2008-12-01

    Climate change drives drying and acidification of many rivers and lakes. Abundant sedimentary iron in these systems oxidizes chemically and biologically to form iron-ox(yhydrox)ide crusts and "hardpans". Given generally high sulfate concentrations, the mobilization and cycling of iron in these environments can be strongly influenced by bacterial sulfate reduction. Sulfate-reducing bacteria (SRB) induce reductive dissolution of oxidized iron phases by producing the reductant bisulfide as a metabolic product. These environmentally ubiquitous microbes also recycle much of the fixed carbon in sediment-hosted microbial mat communities. With prevalent drying, the buffering capacity for protons liberated from iron oxidation is exceeded, and the activity of sulfate-reducers is restricted to those species capable of tolerating low pH (and generally highly saline, i.e. sulfate-rich) conditions. These species will sustain the recycling of iron from more crystalline phases to more bioavailable species, as well as act as the only source of bisulfide for photosynthesizing microbial communities. The phylogeny and physiology of acid-tolerant SRB is therefore important to Fe, S and C cycling in iron-rich sedimentary environments, particularly those on a geochemical trajectory towards acidification. Previous studies have shown that these SRB species tend to be highly novel. We studied two distinct environments along a geochemical continuum towards acidification. In both settings, iron redox transformations exert a major, if not controlling, influence on reduction potential. An acidified, iron- rich tidal marsh receiving acid-mine drainage (San Francisco Bay, CA, USA) contained abundant textural evidence for reductive dissolution of Fe(III) in sediments with pH values varying from 2.4 - 3.8. From these sediments, full-length novel dsrAB gene sequences from acid-tolerant SRB were recovered, and sulfur isotope profiles reflected biological fractionation of sulfur under even the most

  8. Sex-dependent activity of the spinal excitatory amino acid transporter: Role of estrous cycle.

    PubMed

    Sajjad, Jahangir; Felice, Valeria D; Golubeva, Anna V; Cryan, John F; O'Mahony, Siobhain M

    2016-10-01

    Females are more likely to experience visceral pain than males, yet mechanisms underlying this sex bias are not fully elucidated. Moreover, pain sensitivity can change throughout the menstrual cycle. Alterations in the glutamatergic system have been implicated in several pain-disorders; however, whether these are sex-dependent is unclear. Thus, we aimed to investigate sex differences in the spinal cord glutamate uptake and how it varies across the estrous cycle. The activity of the glutamate transporters, excitatory amino acid transporters (EAATs) was assessed using an ex vivo aspartate radioactive uptake assay in the lumbosacral spinal cord in Sprague-Dawley male and female rats. The gene expression of EAATs, glutamate receptor subunits NR1 and NR2B and the estrogen receptors ERα & ERβ in the spinal cord were also analyzed. EAAT activity was lower in females, particularly during the estrus phase, and this was the only cycle stage that was responsive to the pharmacological effects of the EAATs activator riluzole. Interestingly, EAAT1 mRNA expression was lower in high-estrogen and high-ERα states compared to diestrus in females. We conclude that the Spinal EAAT activity in females is different to that in males, and varies across the estrous cycle. Furthermore, the expression levels of estrogen receptors also showed a cycle-dependent pattern that may affect EAATs function and expression. PMID:27471194

  9. Dietary Deficiency of Essential Amino Acids Rapidly Induces Cessation of the Rat Estrous Cycle

    PubMed Central

    Bannai, Makoto; Ichimaru, Toru; Nakano, Sayako; Murata, Takuya; Higuchi, Takashi; Takahashi, Michio

    2011-01-01

    Reproductive functions are regulated by the sophisticated coordination between the neuronal and endocrine systems and are sustained by a proper nutritional environment. Female reproductive function is vulnerable to effects from dietary restrictions, suggesting a transient adaptation that prioritizes individual survival over reproduction until a possible future opportunity for satiation. This adaptation could also partially explain the existence of amenorrhea in women with anorexia nervosa. Because amino acid nutritional conditions other than caloric restriction uniquely alters amino acid metabolism and affect the hormonal levels of organisms, we hypothesized that the supply of essential amino acids in the diet plays a pivotal role in the maintenance of the female reproductive system. To test this hypothesis, we examined ovulatory cyclicity in female rats under diets that were deficient in threonine, lysine, tryptophan, methionine or valine. Ovulatory cyclicity was monitored by daily cytological evaluations of vaginal smears. After continuous feeding of the deficient diet, a persistent diestrus or anovulatory state was induced most quickly by the valine-deficient diet and most slowly by the lysine-deficient diet. A decline in the systemic insulin-like growth factor 1 level was associated with a dietary amino acid deficiency. Furthermore, a paired group of rats that were fed an isocaloric diet with balanced amino acids maintained normal estrous cyclicity. These disturbances of the estrous cycle by amino acid deficiency were quickly reversed by the consumption of a normal diet. The continuous anovulatory state in this study is not attributable to a decrease in caloric intake but to an imbalance in the dietary amino acid composition. With a shortage of well-balanced amino acid sources, reproduction becomes risky for both the mother and the fetus. It could be viewed as an adaptation to the diet, diverting resources away from reproduction and reallocating them to

  10. PICMG xTCA Standards Extensions for Physics: New Developments & Future Plans

    SciTech Connect

    Larsen, R.S.; /SLAC

    2010-08-26

    After several years of planning and workshop meetings, a decision was reached in late 2008 to organize PICMG xTCA for Physics Technical Subcommittees to extend the ATCA and MTCA telecom standards for enhanced system performance, availability and interoperability for physics controls and applications hardware and software. Since formation in May-June 2009, the Hardware Technical Subcommittee has developed a number of ATCA, ARTM, AMC, MTCA and RTM extensions to be completed in mid-to-late 2010. The Software Technical Subcommittee is developing guidelines to promote interoperability of modules designed by industry and laboratories, in particular focusing on middleware and generic application interfaces such as Standard Process Model, Standard Device Model and Standard Hardware API. The paper describes the prototype design work completed by the lab-industry partners to date, the timeline for hardware releases to PICMG for approval, and the status of the software guidelines roadmap. The paper also briefly summarizes the program of the 4th xTCA for Physics Workshop immediately preceding the RT2010 Conference. he case for developing ATCA and MicroTCA (xTCA) specification extensions for physics has been covered in several previous papers. Briefly, ATCA and MicroTCA is the first all-serial communication platform available to the physics community to support both massively complex accelerator controls and massively large, high bandwidth and throughput experimental data acquisition systems. The major strength of xTCA is its multi-layer highly scalable managed platform architecture designed to achieve the highest possible system availability. Physics research imaging technologies have driven industrial applications in a wide range of medical scanners, for example, and in turn continue to evolve to exponentially higher speeds and resolution through new computer, communications industry and analog-to-digital conversion chip developments. The high availability managed platform is

  11. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    PubMed Central

    Igamberdiev, Abir U.; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  12. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants.

    PubMed

    Igamberdiev, Abir U; Eprintsev, Alexander T

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  13. C-Myc Induced Compensated Cardiac Hypertrophy Increases Free Fatty Acid Utilization for the Citric Acid Cycle

    SciTech Connect

    Olson, Aaron; Ledee, Dolena; Iwamoto, Kate; Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Isern, Nancy G.; Portman, Michael A.

    2013-02-01

    The protooncogene C-Myc (Myc) regulates cardiac hypertrophy. Myc promotes compensated cardiac function, suggesting that the operative mechanisms differ from those leading to heart failure. Myc regulation of substrate metabolism is a reasonable target, as Myc alters metabolism in other tissues. We hypothesize that Myc-induced shifts in substrate utilization signal and promote compensated hypertrophy. We used cardiac specific Myc-inducible C57/BL6 male mice between 4-6 months old that develop hypertrophy with tamoxifen (tam). Isolated working hearts and 13Carbon (13C )-NMR were used to measure function and fractional contributions (Fc) to the citric acid cycle by using perfusate containing 13C-labeled free fatty acids, acetoacetate, lactate, unlabeled glucose and insulin. Studies were performed at pre-hypertrophy (3-days tam, 3dMyc), established hypertrophy (7-days tam, 7dMyc) or vehicle control (cont). Non-transgenic siblings (NTG) received 7-days tam or vehicle to assess drug effect. Hypertrophy was confirmed by echocardiograms and heart weights. Western blots were performed on key metabolic enzymes. Hypertrophy occurred in 7dMyc only. Cardiac function did not differ between groups. Tam alone did not affect substrate contribution in NTG. Substrate utilization was not significantly altered in 3dMyc versus cont. The free fatty acid FC was significantly greater in 7dMyc vs cont with decreased unlabeled Fc, which is predominately exogenous glucose. Free fatty acid flux to the citric acid cycle increased while lactate flux was diminished in 7dMyc compared to cont. Total protein levels of a panel of key metabolic enzymes were unchanged; however total protein O-GlcNAcylation was increased in 7dMyc. Substrate utilization changes did not precede hypertrophy; therefore they are not the primary signal for cardiac growth in this model. Free fatty acid utilization and oxidation increase at established hypertrophy. Understanding the mechanisms whereby this change maintained

  14. Lead-acid battery with improved cycle life and increased efficiency for lead leveling application and electric road vehicles

    NASA Astrophysics Data System (ADS)

    Winsel, A.; Schulz, J.; Guetlich, K. F.

    1983-11-01

    Lifetime and efficiency of lead acid batteries are discussed. A gas lift pump was used to prevent acid stratification and to reduce the charging factor (down to 1.03 to 1.05). A re-expansion method was applied and an expander depot and a compound separation were built in. Cycle life is increased from 700 cycles to 1690 cycles. Efficiency is increased by energy and time saving due to the reduced charging factor and by the use of a recombination stopper and a charge indicator with remote control. It is suggested that the lead acid system is still one of the best possibilities for electric road vehicle applications.

  15. Effect of Docosahexaenoic Acid on Cell Cycle Pathways in Breast Cell Lines With Different Transformation Degree.

    PubMed

    Rescigno, Tania; Capasso, Anna; Tecce, Mario Felice

    2016-06-01

    n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), abundant in fish, have been shown to affect development and progression of some types of cancer, including breast cancer. The aim of our study was to further analyze and clarify the effects of these nutrients on the molecular mechanisms underlying breast cancer. Following treatments with DHA we examined cell viability, death, cell cycle, and some molecular effects in breast cell lines with different transformation, phenotypic, and biochemical characteristics (MCF-10A, MCF-7, SK-BR-3, ZR-75-1). These investigations showed that DHA is able to affect cell viability, proliferation, and cell cycle progression in a different way in each assayed breast cell line. The activation of ERK1/2 and STAT3 pathways and the expression and/or activation of molecules involved in cell cycle regulation such as p21(Waf1/Cip1) and p53, are very differently regulated by DHA treatments in each cell model. DHA selectively: (i) arrests non tumoral MCF-10A breast cells in G0 /G1 cycle phase, activating p21(Waf1/Cip1) , and p53, (ii) induces to death highly transformed breast cells SK-BR-3, reducing ERK1/2 and STAT3 phosphorylation and (iii) only slightly affects each analyzed process in MCF-7 breast cell line with transformation degree lower than SK-BR-3 cells. These findings suggest a more relevant inhibitory role of DHA within early development and late progression of breast cancer cell transformation and a variable effect in the other phases, depending on individual molecular properties and degree of malignancy of each clinical case. J. Cell. Physiol. 231: 1226-1236, 2016. © 2015 Wiley Periodicals, Inc. PMID:26480024

  16. New low-antimony alloy for straps and cycling service in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Prengaman, R. David

    Lead-antimony alloys used for the positive grids in lead-acid batteries for cycling service have generally used antimony contents of 4.5 wt.% and above. Tubular batteries for cycling service that impart high compression of the active material to the grid surface via gauntlet use alloys with antimony contents as low as 1.5 wt.%. These batteries are generally employed in less-severe cycling service. Value-regulated lead-acid (VRLA) batteries can give good cycling service without lead-antimony in the positive grid, but require a high tin content and high compression. The change in automotive battery positive grid alloys to lead-calcium-tin and the tin contents of VRLA positive grids and straps have dramatically increased the tin content of the recycled grid and strap lead in the USA, Europe, and Australia. The higher tin contents can contaminate the lead used for lead-antimony battery grids and generally must be removed to low levels to meet the specifications. This study describes a low-antimony alloy that contains a substantial amount of tin. The high tin content reduces the rate of corrosion of low-antimony positive grid alloys, improves conductivity, increases the bond between the grid and the active material, and cycles as well as the traditional 5-6 wt.% antimony alloys employed in conventional flat-plate batteries. The alloy is also used as a corrosion-resistant cast-on strap alloy for automotive batteries for high temperature service, as well as for posts, bushings, and connectors for all wet batteries.

  17. Factors Affecting the Pathways of Glucose Catabolism and the Tricarboxylic Acid Cycle in Pseudomonas natriegens

    PubMed Central

    Cho, H. W.; Eagon, R. G.

    1967-01-01

    Less than 50% of theoretical oxygen uptake was observed when glucose was dissimilated by resting cells of Pseudomonas natriegens. Low oxygen uptakes were also observed when a variety of other substrates were dissimilated. When uniformly labeled glucose-14C was used as substrate, 56% of the label was shown to accumulate in these resting cells. This material consisted, in part, of a polysaccharide which, although it did not give typical glycogen reactions, yielded glucose after its hydrolysis. Resting cells previously cultivated on media containing glucose completely catabolized glucose and formed a large amount of pyruvate within 30 min. Resting cells cultivated in the absence of glucose catabolized glucose more slowly and produced little pyruvate. Pyruvate disappeared after further incubation. In this latter case, experimental results suggested (i) that pyruvate was converted to other acidic products (e.g., acetate and lactate) and (ii) that pyruvate was further catabolized via the tricarboxylic acid cycle. Growth on glucose repressed the level of key enzymes of the tricarboxylic acid cycle and of lactic dehydrogenase. Growth on glycerol stimulated the level of these enzymes. A low level of isocitratase, but not malate synthetase, was noted in extracts of glucose-grown cells. Isocitric dehydrogenase was shown to require nicotinamide adenine dinucleotide phosphate (NADP) as cofactor. Previous experiments have shown that reduced NADP (NADPH2) cannot be readily oxidized and that pyridine nucleotide transhydrogenase could not be detected in extracts. It was concluded that acetate, lactate, and pyruvate accumulate under growing conditions when P. natriegens is cultivated on glucose (i) because of a rapid initial catabolism of glucose via an aerobic glycolytic pathway and (ii) because of a sluggishly functioning tricarboxylic acid cycle due to the accumulation of NADPH2 and to repressed levels of key enzymes. PMID:4381634

  18. Trichloroacetic acid

    Integrated Risk Information System (IRIS)

    Trichloroacetic acid ( TCA ) ; CASRN 76 - 03 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonca

  19. Sirt3 promotes the urea cycle and fatty acid oxidation during dietary restriction.

    PubMed

    Hallows, William C; Yu, Wei; Smith, Brian C; Devries, Mark K; Devires, Mark K; Ellinger, James J; Someya, Shinichi; Shortreed, Michael R; Prolla, Tomas; Markley, John L; Smith, Lloyd M; Zhao, Shimin; Guan, Kun-Liang; Denu, John M

    2011-01-21

    Emerging evidence suggests that protein acetylation is a broad-ranging regulatory mechanism. Here we utilize acetyl-peptide arrays and metabolomic analyses to identify substrates of mitochondrial deacetylase Sirt3. We identified ornithine transcarbamoylase (OTC) from the urea cycle, and enzymes involved in β-oxidation. Metabolomic analyses of fasted mice lacking Sirt3 (sirt3(-/-)) revealed alterations in β-oxidation and the urea cycle. Biochemical analysis demonstrated that Sirt3 directly deacetylates OTC and stimulates its activity. Mice under caloric restriction (CR) increased Sirt3 protein levels, leading to deacetylation and stimulation of OTC activity. In contrast, sirt3(-/-) mice failed to deacetylate OTC in response to CR. Inability to stimulate OTC under CR led to a failure to reduce orotic acid levels, a known outcome of OTC deficiency. Thus, Sirt3 directly regulates OTC activity and promotes the urea cycle during CR, and the results suggest that under low energy input, Sirt3 modulates mitochondria by promoting amino acid catabolism and β-oxidation. PMID:21255725

  20. Sodium phenylbutyrate decreases plasma branched-chain amino acids in patients with urea cycle disorders.

    PubMed

    Burrage, Lindsay C; Jain, Mahim; Gandolfo, Laura; Lee, Brendan H; Nagamani, Sandesh C S

    2014-01-01

    Sodium phenylbutyrate (NaPBA) is a commonly used medication for the treatment of patients with urea cycle disorders (UCDs). Previous reports involving small numbers of patients with UCDs have shown that NaPBA treatment can result in lower plasma levels of the branched-chain amino acids (BCAA) but this has not been studied systematically. From a large cohort of patients (n=553) with UCDs enrolled in the Longitudinal Study of Urea Cycle Disorders, a collaborative multicenter study of the Urea Cycle Disorders Consortium, we evaluated whether treatment with NaPBA leads to a decrease in plasma BCAA levels. Our analysis shows that NaPBA use independently affects the plasma BCAA levels even after accounting for multiple confounding covariates. Moreover, NaPBA use increases the risk for BCAA deficiency. This effect of NaPBA seems specific to plasma BCAA levels, as levels of other essential amino acids are not altered by its use. Our study, in an unselected population of UCD subjects, is the largest to analyze the effects of NaPBA on BCAA metabolism and potentially has significant clinical implications. Our results indicate that plasma BCAA levels should to be monitored in patients treated with NaPBA since patients taking the medication are at increased risk for BCAA deficiency. On a broader scale, these findings could open avenues to explore NaPBA as a therapy in maple syrup urine disease and other common complex disorders with dysregulation of BCAA metabolism. PMID:25042691

  1. Sirt3 promotes the urea cycle and fatty acid oxidation during dietary restriction

    PubMed Central

    Hallows, William C.; Yu, Wei; Smith, Brian C.; Devries, Mark K.; Ellinger, James J.; Someya, Shinichi; Shortreed, Michael R.; Prolla, Tomas; Markley, John L.; Smith, Lloyd M.; Zhao, Shimin; Guan, Kun-Liang; Denu, John M.

    2011-01-01

    Summary Emerging evidence suggests that protein acetylation is a broad-ranging regulatory mechanism. Here we utilize acetyl-peptide arrays and metabolomic analyses to identify substrates of mitochondrial deacetylase Sirt3. We identified ornithine transcarbamoylase (OTC) from the urea cycle, and enzymes involved in β-oxidation. Metabolomic analyses of fasted mice lacking Sirt3 (sirt3−/−) revealed alterations in β-oxidation and the urea cycle. Biochemical analysis demonstrated that Sirt3 directly deacetylates OTC and stimulates its activity. Mice under caloric restriction (CR) increased Sirt3 protein levels, leading to deacetylation and stimulation of OTC activity. In contrast, sirt3−/− mice failed to deacetylate OTC in response to CR. Inability to stimulate OTC under CR led to a failure to reduce orotic acid levels, a known outcome of OTC deficiency. Thus, Sirt3 directly regulates OTC activity and promotes the urea cycle during CR, and the results suggest that under low energy input, Sirt3 modulates mitochondria by promoting amino-acid catabolism and β-oxidation. PMID:21255725

  2. The transcriptional regulation of the glyoxylate cycle in SAR11 in response to iron fertilization in the Southern Ocean.

    PubMed

    Beier, Sara; Gálvez, María J; Molina, Veronica; Sarthou, Géraldine; Quéroué, Fabien; Blain, Stephane; Obernosterer, Ingrid

    2015-06-01

    The tricarboxylic acid (TCA) cycle is a central metabolic pathway that is present in all aerobic organisms and initiates the respiration of organic material. The glyoxylate cycle is a variation of the TCA cycle, where organic material is recycled for subsequent assimilation into cell material instead of being released as carbon dioxide. Despite the importance for the fate of organic matter, the environmental factors that induce the glyoxylate cycle in microbial communities remain poorly understood. In this study, we assessed the expression of isocitrate lyase, the enzyme that induces the switch to the glyoxylate cycle, of the ubiquitous SAR11 clade in response to natural iron fertilization in the Southern Ocean. The cell-specific transcriptional regulation of the glyoxylate cycle, as determined by the ratio between copy numbers of isocitrate lyase gene transcripts and isocitrate genes, was consistently lower in iron fertilized than in high-nutrient, low chlorophyll waters (by 2.4- to 16.5-fold). SAR11 cell-specific isocitrate lyase gene transcription was negatively correlated to chlorophyll a, and bulk bacterial heterotrophic metabolism. We conclude that the glyoxylate cycle is a metabolic strategy for SAR11 that is highly sensitive to the degree of iron and carbon limitation in the marine environment. PMID:25625554

  3. Dynamic metabolic modelling of volatile fatty acids conversion to polyhydroxyalkanoates by a mixed microbial culture.

    PubMed

    Pardelha, Filipa; Albuquerque, Maria G E; Reis, Maria A M; Oliveira, Rui; Dias, João M L

    2014-06-25

    In this work, we present a dynamic metabolic model that describes the uptake of complex mixtures of volatile fatty acids (VFA) and respective conversion into PHA by mixed microbial cultures (MMC). This model builds upon a previously published flux balance analysis model [1] that identified the minimization of TCA cycle activity as the key metabolic objective to predict PHA storage fluxes and respective composition. The model was calibrated either with experimental data of PHA production from fermented sugar cane molasses or from synthetic mixtures of VFA. All PHA production experiments were performed using a MMC selected with fermented sugar cane molasses under feast and famine regimen. The model was able to capture the process dynamics denoted by an excellent fit between experimental and computed time profiles of concentrations with the regression coefficients always above 0.92. The introduced VFA uptake regulatory factor reflects the decrease of acetyl-CoA and propionyl-CoA available to TCA cycle in conformity with the hypothesis that the minimization of TCA cycle is a key metabolic objective for MMC subjected to feast and famine regimen for the maximization of PHA production. PMID:23933561

  4. Ecophysiology of Fe-Cycling Bacteria in Acidic Sediments ▿ †

    PubMed Central

    Lu, Shipeng; Gischkat, Stefan; Reiche, Marco; Akob, Denise M.; Hallberg, Kevin B.; Küsel, Kirsten

    2010-01-01

    Using a combination of cultivation-dependent and -independent methods, this study aimed to elucidate the diversity of microorganisms involved in iron cycling and to resolve their in situ functional links in sediments of an acidic lignite mine lake. Using six different media with pH values ranging from 2.5 to 4.3, 117 isolates were obtained that grouped into 38 different strains, including 27 putative new species with respect to the closest characterized strains. Among the isolated strains, 22 strains were able to oxidize Fe(II), 34 were able to reduce Fe(III) in schwertmannite, the dominant iron oxide in this lake, and 21 could do both. All isolates falling into the Gammaproteobacteria (an unknown Dyella-like genus and Acidithiobacillus-related strains) were obtained from the top acidic sediment zones (pH 2.8). Firmicutes strains (related to Bacillus and Alicyclobacillus) were only isolated from deep, moderately acidic sediment zones (pH 4 to 5). Of the Alphaproteobacteria, Acidocella-related strains were only isolated from acidic zones, whereas Acidiphilium-related strains were isolated from all sediment depths. Bacterial clone libraries generally supported and complemented these patterns. Geobacter-related clone sequences were only obtained from deep sediment zones, and Geobacter-specific quantitative PCR yielded 8 × 105 gene copy numbers. Isolates related to the Acidobacterium, Acidocella, and Alicyclobacillus genera and to the unknown Dyella-like genus showed a broad pH tolerance, ranging from 2.5 to 5.0, and preferred schwertmannite to goethite for Fe(III) reduction. This study highlighted the variety of acidophilic microorganisms that are responsible for iron cycling in acidic environments, extending the results of recent laboratory-based studies that showed this trait to be widespread among acidophiles. PMID:20971876

  5. Deciphering Carbamoylpolyoxamic Acid Biosynthesis Reveals Unusual Acetylation Cycle Associated with Tandem Reduction and Sequential Hydroxylation.

    PubMed

    Qi, Jianzhao; Wan, Dan; Ma, Hongmin; Liu, Yuanzhen; Gong, Rong; Qu, Xudong; Sun, Yuhui; Deng, Zixin; Chen, Wenqing

    2016-08-18

    Polyoxin, produced by Streptomcyes cacaoi var. asoensis and Streptomyces aureochromogenes, contains two non-proteinogenic amino acids, carbamoylpolyoxamic acid (CPOAA) and polyoximic acid. Although the CPOAA moiety is highly unusual, its biosynthetic logic has remained enigmatic for decades. Here, we address CPOAA biosynthesis by reconstitution of its pathway. We demonstrated that its biosynthesis is initiated by a versatile N-acetyltransferase, PolN, catalyzing L-glutamate (1) to N-acetyl glutamate (2). Remarkably, we verified that PolM, a previously annotated dehydrogenase, catalyzes an unprecedented tandem reduction of acyl-phosphate to aldehyde, and subsequently to alcohol. We also unveiled a distinctive acetylation cycle catalyzed by PolN to synthesize α-amino-δ-hydroxyvaleric acid (6). Finally, we report that PolL is capable of converting a rare sequential hydroxylation of α-amino-δ-carbamoylhydroxyvaleric acid (7) to CPOAA. PolL represents an intriguing family of Fe(II)-dependent α-ketoglutarate dioxygenase with a cupin fold. These data illustrate several novel enzymatic reactions, and also set a foundation for rational pathway engineering for polyoxin production. PMID:27541195

  6. The partial state-of-charge cycle performance of lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Takeuchi, Taisuke; Sawai, Ken; Tsuboi, Yuichi; Shiota, Masashi; Ishimoto, Shinji; Hirai, Nobumitsu; Osumi, Shigeharu

    Negative plate lugs of flooded lead-acid battery were corroded during partial state-of-charge (PSoC) pattern cycle life tests simulated from stop and go vehicle driving. Potential step was applied to Pb-Ca-Sn alloy electrode at various potential and time regimes, and the electrode surface was observed by in situ electrochemical atomic force microscope (EC-AFM) to investigate the corrosion mechanisms during the potential step cycles. It was found out that the severe corrosion occurs when the oxidation of Pb to PbSO 4 and partial reduction of passive layer of PbSO 4 take turns many times. It was also found out that the periodic full charge, the optimization of the alloy composition, addition of the material that may make the reaction mechanism change to electrolyte were effective to suppress the corrosion rate.

  7. Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids

    USGS Publications Warehouse

    Scott, D.T.; Runkel, R.L.; McKnight, Diane M.; Voelker, B.M.; Kimball, B.A.; Carraway, E.R.

    2003-01-01

    An in-stream injection of two dissolved organic acids (phthalic and aspartic acids) was performed in an acidic mountain stream to assess the effects of organic acids on Fe photoreduction and H2O2 cycling. Results indicate that the fate of Fe is dependent on a net balance of oxidative and reductive processes, which can vary over a distance of several meters due to changes in incident light and other factors. Solution phase photoreduction rates were high in sunlit reaches and were enhanced by the organic acid addition but were also limited by the amount of ferric iron present in the water column. Fe oxide photoreduction from the streambed and colloids within the water column resulted in an increase in the diurnal load of total filterable Fe within the experimental reach, which also responded to increases in light and organic acids. Our results also suggest that Fe(II) oxidation increased in response to the organic acids, with the result of offsetting the increase in Fe(II) from photoreductive processes. Fe(II) was rapidly oxidized to Fe(III) after sunset and during the day within a well-shaded reach, presumably through microbial oxidation. H2O 2, a product of dissolved organic matter photolysis, increased downstream to maximum concentrations of 0.25 ??M midday. Kinetic calculations show that the buildup of H2O2 is controlled by reaction with Fe(III), but this has only a small effect on Fe(II) because of the small formation rates of H2O2 compared to those of Fe(II). The results demonstrate the importance of incorporating the effects of light and dissolved organic carbon into Fe reactive transport models to further our understanding of the fate of Fe in streams and lakes.

  8. Longitudinal Metabolomic Profiling of Amino Acids and Lipids across Healthy Pregnancy.

    PubMed

    Lindsay, Karen L; Hellmuth, Christian; Uhl, Olaf; Buss, Claudia; Wadhwa, Pathik D; Koletzko, Berthold; Entringer, Sonja

    2015-01-01

    Pregnancy is characterized by a complexity of metabolic processes that may impact fetal development and ultimately, infant health outcomes. However, our understanding of whole body maternal and fetal metabolism during this critical life stage remains incomplete. The objective of this study is to utilize metabolomics to profile longitudinal patterns of fasting maternal metabolites among a cohort of non-diabetic, healthy pregnant women in order to advance our understanding of changes in protein and lipid concentrations across gestation, the biochemical pathways by which they are metabolized and to describe variation in maternal metabolites between ethnic groups. Among 160 pregnant women, amino acids, tricarboxylic acid (TCA) cycle intermediates, keto-bodies and non-esterified fatty acids were detected by liquid chromatography coupled with mass spectrometry, while polar lipids were detected through flow-injected mass spectrometry. The maternal plasma concentration of several essential and non-essential amino acids, long-chain polyunsaturated fatty acids, free carnitine, acetylcarnitine, phosphatidylcholines and sphingomyelins significantly decreased across pregnancy. Concentrations of several TCA intermediates increase as pregnancy progresses, as well as the keto-body β-hydroxybutyrate. Ratios of specific acylcarnitines used as indicators of metabolic pathways suggest a decreased beta-oxidation rate and increased carnitine palmitoyltransferase-1 enzyme activity with advancing gestation. Decreasing amino acid concentrations likely reflects placental uptake and tissue biosynthesis. The absence of any increase in plasma non-esterified fatty acids is unexpected in the catabolic phase of later pregnancy and may reflect enhanced placental fatty acid uptake and utilization for fetal tissue growth. While it appears that energy production through the TCA cycle increases as pregnancy progresses, decreasing patterns of free carnitine and acetylcarnitine as well as increased

  9. Longitudinal Metabolomic Profiling of Amino Acids and Lipids across Healthy Pregnancy

    PubMed Central

    Lindsay, Karen L.; Hellmuth, Christian; Uhl, Olaf; Buss, Claudia; Wadhwa, Pathik D.; Koletzko, Berthold; Entringer, Sonja

    2015-01-01

    Pregnancy is characterized by a complexity of metabolic processes that may impact fetal development and ultimately, infant health outcomes. However, our understanding of whole body maternal and fetal metabolism during this critical life stage remains incomplete. The objective of this study is to utilize metabolomics to profile longitudinal patterns of fasting maternal metabolites among a cohort of non-diabetic, healthy pregnant women in order to advance our understanding of changes in protein and lipid concentrations across gestation, the biochemical pathways by which they are metabolized and to describe variation in maternal metabolites between ethnic groups. Among 160 pregnant women, amino acids, tricarboxylic acid (TCA) cycle intermediates, keto-bodies and non-esterified fatty acids were detected by liquid chromatography coupled with mass spectrometry, while polar lipids were detected through flow-injected mass spectrometry. The maternal plasma concentration of several essential and non-essential amino acids, long-chain polyunsaturated fatty acids, free carnitine, acetylcarnitine, phosphatidylcholines and sphingomyelins significantly decreased across pregnancy. Concentrations of several TCA intermediates increase as pregnancy progresses, as well as the keto-body β-hydroxybutyrate. Ratios of specific acylcarnitines used as indicators of metabolic pathways suggest a decreased beta-oxidation rate and increased carnitine palmitoyltransferase-1 enzyme activity with advancing gestation. Decreasing amino acid concentrations likely reflects placental uptake and tissue biosynthesis. The absence of any increase in plasma non-esterified fatty acids is unexpected in the catabolic phase of later pregnancy and may reflect enhanced placental fatty acid uptake and utilization for fetal tissue growth. While it appears that energy production through the TCA cycle increases as pregnancy progresses, decreasing patterns of free carnitine and acetylcarnitine as well as increased

  10. Corrosive Resistant Diamond Coatings for the Acid Based Thermo-Chemical Hydrogen Cycles

    SciTech Connect

    Mark A. Prelas

    2009-06-25

    This project was designed to test diamond, diamond-like and related materials in environments that are expected in thermochemical cycles. Our goals were to build a High Temperature Corrosion Resistance (HTCR) test stand and begin testing the corrosive properties of barious materials in a high temperature acidic environment in the first year. Overall, we planned to test 54 samples each of diamond and diamond-like films (of 1 cm x 1 cm area). In addition we use a corrosion acceleration method by treating the samples at a temperature much larger than the expected operating temperature. Half of the samples will be treated with boron using the FEDOA process.

  11. To complete its replication cycle, a shrimp virus changes the population of long chain fatty acids during infection via the PI3K-Akt-mTOR-HIF1α pathway.

    PubMed

    Hsieh, Yun-Chieh; Chen, Yi-Min; Li, Chun-Yuan; Chang, Yu-Han; Liang, Suh-Yuen; Lin, Shu-Yu; Lin, Chang-Yi; Chang, Sheng-Hsiung; Wang, Yi-Jan; Khoo, Kay-Hooi; Aoki, Takashi; Wang, Han-Ching

    2015-11-01

    White spot syndrome virus (WSSV), the causative agent of white spot disease (WSD), is a serious and aggressive shrimp viral pathogen with a worldwide distribution. At the genome replication stage (12 hpi), WSSV induces a metabolic rerouting known as the invertebrate Warburg effect, which boosts the availability of energy and biosynthetic building blocks in the host cell. Here we show that unlike the lipogenesis that is seen in cancer cells that are undergoing the Warburg effect, at 12 hpi, all of the long chain fatty acids (LCFAs) were significantly decreased in the stomach cells of WSSV-infected shrimp. By means of this non-selective WSSV-induced lipolysis, the LCFAs were apparently diverted into β-oxidation and used to replenish the TCA cycle. Conversely, at 24 hpi, when the Warburg effect had ceased, most of the LCFAs were significantly up-regulated and the composition was also significantly altered. In crayfish these changes were in a direction that appeared to favor the formation of WSSV virion particles. We also found that, at 24 hpi, but not at 12 hpi, the PI3K-Akt-mTOR-HIF1α pathway induced the expression of fatty acid synthase (FAS), an enzyme which catalyzes the conversion of acetyl-CoA into LCFAs. WSSV virion formation was impaired in the presence of the FAS inhibitor C75, although viral gene and viral DNA levels were unaffected. WSSV therefore appears to use the PI3K-Akt-mTOR pathway to induce lipid biosynthesis at 24 hpi in order to support viral morphogenesis. PMID:26112000

  12. Stability of Supported Platinum Sulfuric Acid Decomposition Catalysts for use in Thermochemical Water Splitting Cycles

    SciTech Connect

    Daniel M. Ginosar; Lucia M. Petkovic; Anne W. Glenn; Kyle C. Burch

    2007-03-01

    The activity and stability of several metal oxide supported platinum catalysts were explored for the sulfuric acid decomposition reaction. The acid decomposition reaction is common to several sulfur based thermochemical water splitting cycles. Reactions were carried out using a feed of concentrated liquid sulfuric acid (96 wt%) at atmospheric pressure at temperatures between 800 and 850 °C and a weight hour space velocity of 52 g acid/g catalyst/hr. Reactions were run at these high space velocities such that variations in kinetics were not masked by surplus catalyst. The influence of exposure to reaction conditions was explored for three catalysts; 0.1-0.2 wt% Pt supported on alumina, zirconia and titania. The higher surface area Pt/Al2O3 and Pt/ZrO2 catalysts were found to have the highest activity but deactivated rapidly. A low surface area Pt/TiO2 catalyst was found to have good stability in short term tests, but slowly lost activity for over 200 hours of continuous operation.

  13. DIBROMOACETIC ACID-INDUCED ELEVATIONS OF ESTRADIOL IN THE CYCLING AND OVARIECTOMOZED/ESTRADIOL-IMPLANTED FEMALE RAT

    EPA Science Inventory

    Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations of Estradiol in Both Cycling and Ovariectomized / Estradiol-implanted Female Rats

    ABSTRACT
    Haloacetic acids are one of the principal classes of disinfection by-products generated by the chlorination of mun...

  14. Seasonal changes in nitrogen-cycle gene abundances and in bacterial communities in acidic forest soils.

    PubMed

    Jung, Jaejoon; Yeom, Jinki; Han, Jiwon; Kim, Jisun; Park, Woojun

    2012-06-01

    The abundance of genes related to the nitrogen biogeochemical cycle and the microbial community in forest soils (bacteria, archaea, fungi) were quantitatively analyzed via real-time PCR using 11 sets of specific primers amplifying nifH, bacterial amoA, archaeal amoA, narG, nirS, nirK, norB, nosZ, bacterial 16S rRNA gene, archaeal 16S rRNA gene, and the ITS sequence of fungi. Soils were sampled from Bukhan Mountain from September of 2010 to July of 2011 (7 times). Bacteria were the predominant microbial community in all samples. However, the abundance of archaeal amoA was greater than bacterial amoA throughout the year. The abundances of nifH, nirS, nirK, and norB genes changed in a similar pattern, while narG and nosZ appeared in sensitive to the environmental changes. Clone libraries of bacterial 16S rRNA genes were constructed from summer and winter soil samples and these revealed that Acidobacteria was the most predominant phylum in acidic forest soil environments in both samples. Although a specific correlation of environmental factor and gene abundance was not verified by principle component analysis, our data suggested that the combination of biological, physical, and chemical characteristics of forest soils created distinct conditions favoring the nitrogen biogeochemical cycle and that bacterial communities in undisturbed acidic forest soils were quite stable during seasonal change. PMID:22752898

  15. Biochar impacts soil microbial community composition and nitrogen cycling in an acidic soil planted with rape.

    PubMed

    Xu, Hui-Juan; Wang, Xiao-Hui; Li, Hu; Yao, Huai-Ying; Su, Jian-Qiang; Zhu, Yong-Guan

    2014-08-19

    Biochar has been suggested to improve acidic soils and to mitigate greenhouse gas emissions. However, little has been done on the role of biochar in ameliorating acidified soils induced by overuse of nitrogen fertilizers. In this study, we designed a pot trial with an acidic soil (pH 4.48) in a greenhouse to study the interconnections between microbial community, soil chemical property changes, and N2O emissions after biochar application. The results showed that biochar increased plant growth, soil pH, total carbon, total nitrogen, C/N ratio, and soil cation exchange capacity. The results of high-throughput sequencing showed that biochar application increased α-diversity significantly and changed the relative abundances of some microbes that are related with carbon and nitrogen cycling at the family level. Biochar amendment stimulated both nitrification and denitrification processes, while reducing N2O emissions overall. Results of redundancy analysis indicated biochar could shift the soil microbial community by changing soil chemical properties, which modulate N-cycling processes and soil N2O emissions. The significantly increased nosZ transcription suggests that biochar decreased soil N2O emissions by enhancing its further reduction to N2. PMID:25054835

  16. Seasonal and diurnal cycles of ammonia, nitrous acid and nitric acid at a forest site in Finland

    NASA Astrophysics Data System (ADS)

    Virkkula, A.; Makkonen, U.; Mäntykenttä, J.; Hakola, H.

    2012-04-01

    Background In July - August 2010 a large campaign "Hyytiälä United Measurements of Photochemistry and Particles in Air - Comprehensive Organic Precursor Emission Concentration 2010 (HUMPPA - COPEC-10)", was conducted in a boreal forest at the SMEAR II station in Hyytiälä, southwestern central Finland. The general goal was to study links between gas phase oxidation chemistry and particle properties and processes. The Finnish Meteorological Institute contributed to the campaign with an on-line analyzer MARGA 2S (Ten Brink et al., 2007) for semi-continuous (1-hr time resolution) measurement of water-soluble gases and ions. Concentrations of gases (HCl, HNO3, HNO2, NH3, SO2) and major ions in particles (Cl, NO3, SO4, NH4, Na, K, Mg, Ca) were measured in two size fractions: PM2.5 and PM10. The MARGA was kept running at SMEAR II also after the campaign. Here we discuss data collected until 30 April, 2011, and restrict the analysis to the nitrogen-containing gases. Ammonia plays a key role in neutralizing acidic atmospheric compounds and in aerosol formation. The concentration of semi-volatile aerosol species such as ammonium nitrate and ammonium chloride is strongly dependent on the gas phase precursors, NH3, HNO3 and HCl. HONO is of atmospheric importance due to its expected significant contribution to the production of OH radicals. Results and discussion The median concentrations of ammonia (NH3), nitrous acid (HONO) and nitric acid (HNO3) during whole period of 21 June 2010 - 30 April 2011 were 85, 54, and 57 ppt, respectively. The seasonal cycle was such that in summer the concentrations of all of these gases were the highest, the respective medians were 356, 70, and 81 ppt in June 21 - August 12, and lowest in winter (December - February), the respective medians were 38, 54, and 52 ppt. A very clear diurnal cycle of all these gases was observed, especially in July. In December there were no cyclic diurnal variation of these but in spring, especially in April the

  17. THE EFFECT OF ANOLYTE PRODUCT ACID CONCENTRATION ON HYBRID SULFUR CYCLE PERFORMANCE

    SciTech Connect

    Gorensek, M.; Summers, W.

    2010-03-24

    The Hybrid Sulfur (HyS) cycle (Fig. 1) is one of the simplest, all-fluids thermochemical cycles that has been devised for splitting water with a high-temperature nuclear or solar heat source. It was originally patented by Brecher and Wu in 1975 and extensively developed by Westinghouse in the late 1970s and early 1980s. As its name suggests, the only element used besides hydrogen and oxygen is sulfur, which is cycled between the +4 and +6 oxidation states. HyS comprises two steps. One is the thermochemical (>800 C) decomposition of sulfuric acid (H{sub 2}SO{sub 4}) to sulfur dioxide (SO{sub 2}), oxygen (O{sub 2}), and water. H{sub 2}SO{sub 4} = SO{sub 2} + 1/2 O{sub 2} + H{sub 2}O. The other is the SO{sub 2}-depolarized electrolysis of water to H{sub 2}SO{sub 4} and hydrogen (H{sub 2}), SO{sub 2} + 2 H{sub 2}O = H{sub 2}SO{sub 4} + H{sub 2}, E{sup o} = -0.156 V, explaining the 'hybrid' designation. These two steps taken together split water into H{sub 2} and O{sub 2} using heat and electricity. Researchers at the Savannah River National Laboratory (SRNL) and at the University of South Carolina (USC) have successfully demonstrated the use of proton exchange membrane (PEM) electrolyzers (Fig. 2) for the SO{sub 2}-depolarized electrolysis (sulfur oxidation) step, while Sandia National Laboratories (SNL) successfully demonstrated the high-temperature sulfuric acid decomposition (sulfur reduction) step using a bayonet-type reactor (Fig. 3). This latter work was performed as part of the Sulfur-Iodine (SI) cycle Integrated Laboratory Scale demonstration at General Atomics (GA). The combination of these two operations results in a simple process that will be more efficient and cost-effective for the massive production of hydrogen than alkaline electrolysis. Recent developments suggest that the use of PEMs other than Nafion will allow sulfuric acid to be produced at higher concentrations (>60 wt%), offering the possibility of net thermal efficiencies around 50% (HHV basis

  18. Treatment technologies and mechanisms for three odorants at trace level: IPMP, IBMP, and TCA.

    PubMed

    Li, Xin; Lin, Pengfei; Wang, Jun; Liu, Yuanyuan; Li, Yong; Zhang, Xiaojian; Chen, Chao

    2016-01-01

    Odour episodes caused by algal metabolites are gaining more and more attention in recent years. Besides geosmin and 2-methylisoborneol (MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), and 2,4,6-trichloroanisole (TCA) have emerged to be important off-flavour sources. Their low odour threshold concentrations (several ng ·L(-1)), which are even lower than those of MIB and geosmin, pose challenges for treatment strategies. Hence, a practical and efficient mitigation technology is needed. The possible practical technologies, including powdered activated carbon (PAC) adsorption and oxidation by chlorine and potassium permanganate, were investigated. The results indicated that chlorine and potassium permanganate oxidation of the three odorants were unfeasible while PAC adsorption was effective. As for adsorption, TCA, followed by IBMP and IPMP, was most easily removed by PAC. The Freundlich model could well describe the adsorption isotherm data. The adsorption capacities for IPMP, IBMP, and TCA were described as follows: [Formula: see text], [Formula: see text], and [Formula: see text]. For five earthy/musty odorants including geosmin and MIB, octanol/water partition coefficient, molecular weight, and polarizability all promoted adsorption while aqueous solubility showed a negative influence. The hydrophobic interaction was believed to be the dominant force in the adsorption mechanism while the π-electron interaction enhanced adsorption when a benzene ring was present. This result could be used to predict the adsorption performance of emerging odorants. PMID:26150209

  19. Identification of rhythmic subsystems in the circadian cycle of crassulacean acid metabolism under thermoperiodic perturbations.

    PubMed

    Bohn, Andreas; Hinderlich, Sven; Hütt, Marc-Thorsten; Kaiser, Friedemann; Lüttge, Ulrich

    2003-05-01

    Leaves of the Crassulacean acid metabolism (CAM) plant Kalanchoë daigremontiana Hamet et Perrier de la Bâthie show overt circadian rhythms in net CO2 uptake, leaf conductance to water and intercellular CO2 concentration, which are entrained by periodic temperature cycles. To probe their sensitivity to thermoperiodic perturbations, intact leaves were exposed to continuous light intensity and temperature cycles with a period of 16 h, applying a set of different baseline temperatures and thermodriver amplitudes. All three overt rhythms were analyzed with respect to their frequency spectra and their phase relations with the thermodriver. For most stimulation protocols, stomatal conductance and net CO2 change were fully or partially entrained by the temperature pulses, while the internal CO2 concentration remained dominated by oscillations in the circadian range. Prolonged time series recorded for up to 22 d in continuous light underline the robustness of these circadian oscillations. This suggests that the overt circadian rhythm of net CO2 uptake in CAM results from the interaction of two coupled original systems: (i) an endogenous cycle of CO2 fixation in the mesophyll, showing very robust periodic activity, and (ii) stomatal movements that respond to environmental stimuli independently of rhythmic processes in the mesophyll, and thus modulate the gas exchange amplitude. PMID:12817468

  20. Crystal structures of a purple acid phosphatase, representing different steps of this enzyme's catalytic cycle

    PubMed Central

    Schenk, Gerhard; Elliott, Tristan W; Leung, Eleanor; Carrington, Lyle E; Mitić, Nataša; Gahan, Lawrence R; Guddat, Luke W

    2008-01-01

    Background Purple acid phosphatases belong to the family of binuclear metallohydrolases and are involved in a multitude of biological functions, ranging from bacterial killing and bone metabolism in animals to phosphate uptake in plants. Due to its role in bone resorption purple acid phosphatase has evolved into a promising target for the development of anti-osteoporotic chemotherapeutics. The design of specific and potent inhibitors for this enzyme is aided by detailed knowledge of its reaction mechanism. However, despite considerable effort in the last 10 years various aspects of the basic molecular mechanism of action are still not fully understood. Results Red kidney bean purple acid phosphatase is a heterovalent enzyme with an Fe(III)Zn(II) center in the active site. Two new structures with bound sulfate (2.4 Å) and fluoride (2.2 Å) provide insight into the pre-catalytic phase of its reaction cycle and phosphorolysis. The sulfate-bound structure illustrates the significance of an extensive hydrogen bonding network in the second coordination sphere in initial substrate binding and orientation prior to hydrolysis. Importantly, both metal ions are five-coordinate in this structure, with only one nucleophilic μ-hydroxide present in the metal-bridging position. The fluoride-bound structure provides visual support for an activation mechanism for this μ-hydroxide whereby substrate binding induces a shift of this bridging ligand towards the divalent metal ion, thus increasing its nucleophilicity. Conclusion In combination with kinetic, crystallographic and spectroscopic data these structures of red kidney bean purple acid phosphatase facilitate the proposal of a comprehensive eight-step model for the catalytic mechanism of purple acid phosphatases in general. PMID:18234116

  1. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation

    PubMed Central

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-01

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD+] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with 14C-glucose and 3H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD+] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD+] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation. PMID:15550462

  2. Clinical benefit using sperm hyaluronic acid binding technique in ICSI cycles: a systematic review and meta-analysis.

    PubMed

    Beck-Fruchter, Ronit; Shalev, Eliezer; Weiss, Amir

    2016-03-01

    The human oocyte is surrounded by hyaluronic acid, which acts as a natural selector of spermatozoa. Human sperm that express hyaluronic acid receptors and bind to hyaluronic acid have normal shape, minimal DNA fragmentation and low frequency of chromosomal aneuploidies. Use of hyaluronic acid binding assays in intracytoplasmic sperm injection (ICSI) cycles to improve clinical outcomes has been studied, although none of these studies had sufficient statistical power. In this systematic review and meta-analysis, electronic databases were searched up to June 2015 to identify studies of ICSI cycles in which spermatozoa able to bind hyaluronic acid was selected. The main outcomes were fertilization rate and clinical pregnancy rate. Secondary outcomes included cleavage rate, embryo quality, implantation rate, spontaneous abortion and live birth rate. Seven studies and 1437 cycles were included. Use of hyaluronic acid binding sperm selection technique yielded no improvement in fertilization and pregnancy rates. A meta-analysis of all available studies showed an improvement in embryo quality and implantation rate; an analysis of prospective studies only showed an improvement in embryo quality. Evidence does not support routine use of hyaluronic acid binding assays in all ICSI cycles. Identification of patients that might benefit from this technique needs further study. PMID:26776822

  3. Environmental Life Cycle Assessment of Diets with Improved Omega-3 Fatty Acid Profiles.

    PubMed

    Coelho, Carla R V; Pernollet, Franck; van der Werf, Hayo M G

    2016-01-01

    A high incidence of cardiovascular disease is observed worldwide, and dietary habits are one of the risk factors for these diseases. Omega-3 polyunsaturated fatty acids in the diet help to prevent cardiovascular disease. We used life cycle assessment to analyse the potential of two strategies to improve the nutritional and environmental characteristics of French diets: 1) modifying diets by changing the quantities and proportions of foods and 2) increasing the omega-3 contents in diets by replacing mainly animal foods with equivalent animal foods having higher omega-3 contents. We also investigated other possibilities for reducing environmental impacts. Our results showed that a diet compliant with nutritional recommendations for macronutrients had fewer environmental impacts than the current average French diet. Moving from an omnivorous to a vegetarian diet further reduced environmental impacts. Increasing the omega-3 contents in animal rations increased Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) in animal food products. Providing these enriched animal foods in human diets increased their EPA and DHA contents without affecting their environmental impacts. However, in diets that did not contain fish, EPA and DHA contents were well below the levels recommended by health authorities, despite the inclusion of animal products enriched in EPA and DHA. Reducing meat consumption and avoidable waste at home are two main avenues for reducing environmental impacts of diets. PMID:27504959

  4. Environmental Life Cycle Assessment of Diets with Improved Omega-3 Fatty Acid Profiles

    PubMed Central

    Coelho, Carla R. V.; Pernollet, Franck; van der Werf, Hayo M. G.

    2016-01-01

    A high incidence of cardiovascular disease is observed worldwide, and dietary habits are one of the risk factors for these diseases. Omega-3 polyunsaturated fatty acids in the diet help to prevent cardiovascular disease. We used life cycle assessment to analyse the potential of two strategies to improve the nutritional and environmental characteristics of French diets: 1) modifying diets by changing the quantities and proportions of foods and 2) increasing the omega-3 contents in diets by replacing mainly animal foods with equivalent animal foods having higher omega-3 contents. We also investigated other possibilities for reducing environmental impacts. Our results showed that a diet compliant with nutritional recommendations for macronutrients had fewer environmental impacts than the current average French diet. Moving from an omnivorous to a vegetarian diet further reduced environmental impacts. Increasing the omega-3 contents in animal rations increased Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) in animal food products. Providing these enriched animal foods in human diets increased their EPA and DHA contents without affecting their environmental impacts. However, in diets that did not contain fish, EPA and DHA contents were well below the levels recommended by health authorities, despite the inclusion of animal products enriched in EPA and DHA. Reducing meat consumption and avoidable waste at home are two main avenues for reducing environmental impacts of diets. PMID:27504959

  5. Advances in Acid Concentration Membrane Technology for the Sulfur-Iodine Thermochemical Cycle

    SciTech Connect

    Frederick F. Stewart; Christopher J. Orme

    2006-11-01

    One of the most promising cycles for the thermochemical generation of hydrogen is the Sulfur-Iodine (S-I) process, where aqueous HI is thermochemically decomposed into H2 and I2 at approximately 350 degrees Celsius. Regeneration of HI is accomplished by the Bunsen reaction (reaction of SO2, water, and iodine to generate H2SO4 and HI). Furthermore, SO2 is regenerated from the decomposition of H2SO4 at 850 degrees Celsius yielding the SO2 as well as O2. Thus, the cycle actually consists of two concurrent oxidation-reduction loops. As HI is regenerated, co-produced H2SO4 must be separated so that each may be decomposed. Current flowsheets employ a large amount (~83 mol% of the entire mixture) of elemental I2 to cause the HI and the H2SO4 to separate into two phases. To aid in the isolation of HI, which is directly decomposed into hydrogen, water and iodine must be removed. Separation of iodine is facilitated by removal of water. Sulfuric acid concentration is also required to facilitate feed recycling to the sulfuric acid decomposer. Decomposition of the sulfuric acid is an equilibrium limited process that leaves a substantial portion of the acid requiring recycle. Distillation of water from sulfuric acid involves significant corrosion issues at the liquid-vapor interface. Thus, it is desirable to concentrate the acid without boiling. Recent efforts at the INL have concentrated on applying pervaporation through Nafion-117, Nafion-112, and sulfonated poly(etheretherketone) (S-PEEK) membranes for the removal of water from HI/water and HI/Iodine/water feedstreams. In pervaporation, a feed is circulated at low pressure across the upstream side of the membrane, while a vacuum is applied downstream. Selected permeants sorb into the membrane, transport through it, and are vaporized from the backside. Thus, a concentration gradient is established, which provides the driving force for transport. In this work, membrane separations have been performed at temperatures as high as

  6. Dwell Time and Surface Parameter Effects on Removal of Silicone Oil From D6ac Steel Using TCA

    NASA Technical Reports Server (NTRS)

    Boothe, R. E.

    2003-01-01

    This study was conducted to evaluate the impact of dwell time, surface roughness, and the surface activation state on 1,1,1-trichloroethane's (TCA's) effectiveness for removing silicone oil from D6ac steel. Silicone-contaminated test articles were washed with TCA solvent, and then the surfaces were analyzed for residue, using Fourier transform infrared spectroscopy. The predominant factor affecting the ability to remove the silicone oil was surface roughness.

  7. A Study of Krebs Citric Acid Cycle Enzymes in Rice Larvae (Corcyrace phalonica St) During Mycotoxicosis

    PubMed Central

    Hegde, Umashashi C.; Shanmugasundaram, E. R. B.

    1967-01-01

    Krebs citric acid cycle enzymes have been studied in rice moth larvae (Corcyra cephalonica St) reared in groundnut meal control and contaminated with A. flavus, wheat bran control and wheat bran contaminated with A. flavus and also wheat bran containing aflatoxin. It was observed that the activity of enzymes other than succinic oxidase, succinic dehydrogenase and isocitric dehydrogenase were reduced significantly in larvae reared in contaminated groundnut meal when compared with the control. In the case of larvae reared in contaminated wheat bran all the enzymes except succinic oxidase were inhibited when compared to the control larvae. It was also observed that the inhibition of these enzymes is greater in the case of larvae reared in contaminated wheat bran than in contaminated groundnut meal. The higher toxicity of wheat bran has been discussed. PMID:4229935

  8. Prediction of positional isotopomers of the citric acid cycle: the syntactic approach.

    PubMed

    Cohen, D M; Bergman, R N

    1994-03-01

    We propose a syntactic approach to modeling of biochemical fluxes that combines a rule-based description of atomic transfer in chemical reactions with a structurally oriented, stochastic model of chemical reaction kinetics. This approach avoids the use of differential equations to describe the production and disappearance of each molecule. The computer simulation predicts the changes over time in the abundance of each positional isotopomer of every metabolic intermediate in the citric acid cycle of heart cells, subsequent to administration of [2-13C]acetate (including natural abundance of 13C). (Positional isotopomers are isomers that differ in the positions of isotopes within the molecule.) The 32 positional isotopomers of glutamate fell into four groups with similar intragroup dynamics but with very different amplitudes. From the relative abundance of each isotopomer of glutamate, we calculate the relative area of multiplets of the nuclear magnetic resonance spectrum. PMID:7909408

  9. Microbial Fe cycling and mineralization in sediments of an acidic, hypersaline lake (Lake Tyrell, Victoria, Australia)

    NASA Astrophysics Data System (ADS)

    Roden, E. E.; Blöthe, M.; Shelobolina, E.

    2009-12-01

    Lake Tyrrell is a variably acidic, hypersaline, Fe-rich lake located in Victoria, Australia. Terrestrial acid saline lakes like Lake Tyrrell may be analogs for ancient Martian surface environments, as well as possible extant subsurface environments. To investigate the potential for microbial Fe cycling under acidic conditions and high salt concentration, we collected sediment core samples during three field trips between 2006 and 2008 from the southern, acidic edge of the lake. Materials from the cores were used for chemical and mineralogical analyses, as well as for molecular (16S rRNA genes) and culture-based microbiological studies. Near-surface (< 1 m depth) pore fluids contained low but detectable dissolved oxygen (ca. 50 uM), significant dissolved Fe(II) (ca. 500 uM), and nearly constant pH of around 4 - conditions conducive to enzymatic Fe(II) oxidation. High concentrations of Fe(III) oxides begin accumulate at a depth of ca. 10 cm, and may reflect the starting point for formation of massive iron concretions that are evident at and beneath the sediment surface. MPN analyses revealed low (10-100 cells/mL) but detectable populations of aerobic, halophilic Fe(II)-oxidizing organisms on the sediment surface and in the near-surface ground water. With culture-dependent methods at least three different halotolerant lithoautotrophic cultures growing on Fe(II), thiosulfate, or tetrathionate from different acidic sites were obtained. Analysis of 16S rRNA gene sequences revealed that these organisms are similar to previous described gamma proteobacteria Thiobacillus prosperus (95%), Halothiobacillus kellyi (99%), Salinisphaera shabanense (95%) and a Marinobacter species. (98%). 16S rRNA gene pyrosequencing data from two different sites with a pH range between 3 and 4.5 revealed a dominance of gamma proteobacteria. 16S rRNA gene pyrosequencing libraries from both cores were dominated by sequences related to the Ectothiorhodospiraceae family, which includes the taxa

  10. The gamma-aminobutyric acid shunt contributes to closing the tricarboxylic acid cycle in Synechocystis sp PCC 6803

    SciTech Connect

    Xiong, W; Brune, D; Vermaas, WFJ

    2014-07-16

    A traditional 2-oxoglutarate dehydrogenase complex is missing in the cyanobacterial tricarboxylic acid cycle. To determine pathways that convert 2-oxoglutarate into succinate in the cyanobacterium Synechocystis sp. PCC 6803, a series of mutant strains, Delta sll1981, Delta slr0370, Delta slr1022 and combinations thereof, deficient in 2-oxoglutarate decarboxylase (Sll1981), succinate semialdehyde dehydrogenase (Slr0370), and/or in gamma-aminobutyrate metabolism (Slr1022) were constructed. Like in Pseudomonas aeruginosa, N-acetylornithine aminotransferase, encoded by slr1022, was shown to also function as gamma-aminobutyrate aminotransferase, catalysing gamma-aminobutyrate conversion to succinic semialdehyde. As succinic semialdehyde dehydrogenase converts succinic semialdehyde to succinate, an intact gamma-aminobutyrate shunt is present in Synechocystis. The Delta sll1981 strain, lacking 2-oxoglutarate decarboxylase, exhibited a succinate level that was 60% of that in wild type. However, the succinate level in the Delta slr1022 and Delta slr0370 strains and the Delta sll1981/Delta slr1022 and Delta sll1981/Delta slr0370 double mutants was reduced to 20-40% of that in wild type, suggesting that the gamma-aminobutyrate shunt has a larger impact on metabolite flux to succinate than the pathway via 2-oxoglutarate decarboxylase. C-13-stable isotope analysis indicated that the gamma-aminobutyrate shunt catalysed conversion of glutamate to succinate. Independent of the 2-oxoglutarate decarboxylase bypass, the gamma-aminobutyrate shunt is a major contributor to flux from 2-oxoglutarate and glutamate to succinate in Synechocystis sp. PCC 6803.

  11. The Viability of a Nonenzymatic Reductive Citric Acid Cycle Kinetics and Thermochemistry

    NASA Astrophysics Data System (ADS)

    Ross, David S.

    2007-02-01

    The likelihood of a functioning nonenzymatic reductive citric acid cycle, recently proposed as the precursor to biosynthesis on early Earth, is examined on the basis of the kinetics and thermochemistry of the acetate → pyruvate → oxaloacetate → malate sequence. Using data derived from studies of the Pd-catalyzed phosphinate reduction of carbonyl functions it is shown that the rate of conversion of pyruvate to malate with that system would have been much too slow to have played a role in the early chemistry of life, while naturally occurring reduction systems such as the fayalite magnetite quartz and pyrrhotite pyrite magnetite mineral assemblages would have provided even slower conversions. It is also shown that the production of pyruvate from acetate is too highly endoergic to be driven by a naturally occurring energy source such as pyrophosphate. It is thus highly doubtful that the cycle can operate at suitable rates without enzymes, and most unlikely that it could have participated in the chemistry leading to life.

  12. The viability of a nonenzymatic reductive citric acid cycle - Kinetics and thermochemistry

    USGS Publications Warehouse

    Ross, D.S.

    2007-01-01

    The likelihood of a functioning nonenzymatic reductive citric acid cycle, recently proposed as the precursor to biosynthesis on early Earth, is examined on the basis of the kinetics and thermochemistry of the acetate ??? pyruvate ??? oxaloacetate ??? malate sequence. Using data derived from studies of the Pd-catalyzed phosphinate reduction of carbonyl functions it is shown that the rate of conversion of pyruvate to malate with that system would have been much too slow to have played a role in the early chemistry of life, while naturally occurring reduction systems such as the fayalite-magnetite-quartz and pyrrhotite-pyrite-magnetite mineral assemblages would have provided even slower conversions. It is also shown that the production of pyruvate from acetate is too highly endoergic to be driven by a naturally occurring energy source such as pyrophosphate. It is thus highly doubtful that the cycle can operate at suitable rates without enzymes, and most unlikely that it could have participated in the chemistry leading to life. ?? 2006 Springer Science + Business Media B.V.

  13. The viability of a nonenzymatic reductive citric acid cycle--kinetics and thermochemistry.

    PubMed

    Ross, David S

    2007-02-01

    The likelihood of a functioning nonenzymatic reductive citric acid cycle, recently proposed as the precursor to biosynthesis on early Earth, is examined on the basis of the kinetics and thermochemistry of the acetate --> pyruvate --> oxaloacetate --> malate sequence. Using data derived from studies of the Pd-catalyzed phosphinate reduction of carbonyl functions it is shown that the rate of conversion of pyruvate to malate with that system would have been much too slow to have played a role in the early chemistry of life, while naturally occurring reduction systems such as the fayalite-magnetite-quartz and pyrrhotite-pyrite-magnetite mineral assemblages would have provided even slower conversions. It is also shown that the production of pyruvate from acetate is too highly endoergic to be driven by a naturally occurring energy source such as pyrophosphate. It is thus highly doubtful that the cycle can operate at suitable rates without enzymes, and most unlikely that it could have participated in the chemistry leading to life. PMID:17136437

  14. Increased lysine production by flux coupling of the tricarboxylic acid cycle and the lysine biosynthetic pathway--metabolic engineering of the availability of succinyl-CoA in Corynebacterium glutamicum.

    PubMed

    Kind, Stefanie; Becker, Judith; Wittmann, Christoph

    2013-01-01

    In this study, we demonstrate increased lysine production by flux coupling using the industrial work horse bacterium Corynebacterium glutamicum, which was mediated by the targeted interruption of the tricarboxylic acid (TCA) cycle at the level of succinyl-CoA synthetase. The succinylase branch of the lysine production pathway functions as the bridging reaction to convert succinyl-CoA to succinate in this aerobic bacterium. The mutant C. glutamicum ΔsucCD showed a 60% increase in the yield of lysine when compared to the advanced lysine producer which was used as parent strain. This mutant was highly vital and exhibited only a slightly reduced specific growth rate. Metabolic flux analysis with (13)C isotope studies confirmed that the increase in lysine production was mediated by pathway coupling. The novel strain exhibited an exceptional flux profile, which was closer to the optimum performance predicted by in silico pathway analysis than to the large set of lysine-producing strains analyzed thus far. Fluxomics and transcriptomics were applied as further targets for next-level strain engineering to identify the back-up mechanisms that were activated upon deletion of the enzyme in the mutant strain. It seemed likely that the cells partly recruited the glyoxylate shunt as a by-pass route. Additionally, the α-ketoglutarate decarboxylase pathway emerged as the potential compensation mechanism. This novel strategy appears equally promising for Escherichia coli, which is used in the industrial production of lysine, wherein this bacterium synthesizes lysine exclusively by succinyl-CoA activation of pathway intermediates. The channeling of a high flux pathway into a production pathway by pathway coupling is an interesting metabolic engineering strategy that can be explored to optimize bio-production in the future. PMID:22871505

  15. Heteromeric amino acid transporters. In search of the molecular bases of transport cycle mechanisms.

    PubMed

    Palacín, Manuel; Errasti-Murugarren, Ekaitz; Rosell, Albert

    2016-06-15

    Heteromeric amino acid transporters (HATs) are relevant targets for structural studies. On the one hand, HATs are involved in inherited and acquired human pathologies. On the other hand, these molecules are the only known examples of solute transporters composed of two subunits (heavy and light) linked by a disulfide bridge. Unfortunately, structural knowledge of HATs is scarce and limited to the atomic structure of the ectodomain of a heavy subunit (human 4F2hc-ED) and distant prokaryotic homologues of the light subunits that share a LeuT-fold. Recent data on human 4F2hc/LAT2 at nanometer resolution revealed 4F2hc-ED positioned on top of the external loops of the light subunit LAT2. Improved resolution of the structure of HATs, combined with conformational studies, is essential to establish the structural bases for light subunit recognition and to evaluate the functional relevance of heavy and light subunit interactions for the amino acid transport cycle. PMID:27284037

  16. Developments in absorptive glass mat separators for cycling applications and 36 V lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Toniazzo, V.; Lambert, U.

    The major markets for valve-regulated lead-acid (VRLA) batteries are undergoing a radical upheaval. In particular, the telecommunications industry requires more reliable power supplies, and the familiar 12 V electrical system in cars will probably be soon replaced by a 36/42 V system, or by other electrical systems if part of the automotive market is taken over by hybrid electrical vehicles (HEVs). In order to meet these new challenges and enable VRLA batteries to provide a satisfactory life in float and cycling applications in the telecommunication field, or in the high-rate-partial-state-of-charge service required by both 36/42 V automobiles and HEVs, the lead-acid battery industry has to improve substantially the quality of present VRLA batteries based on absorptive glass mat (AGM) technology. Therefore, manufacturing steps and cell components have to be optimized, especially AGM separators as these are key components for better production yields and battery performance. This paper shows how the optimal segregation of the coarse and fine fibres in an AGM separator structure can improve greatly the properties of the material. The superior capillarity, springiness and mechanical properties of the 100% glass Amerglass multilayer separator compared with commercial monolayer counterparts with the same specific surface-area is highlighted.

  17. Glutamate Utilization Couples Oxidative Stress Defense and the Tricarboxylic Acid Cycle in Francisella Phagosomal Escape

    PubMed Central

    Ramond, Elodie; Gesbert, Gael; Rigard, Mélanie; Dairou, Julien; Dupuis, Marion; Dubail, Iharilalao; Meibom, Karin; Henry, Thomas; Barel, Monique; Charbit, Alain

    2014-01-01

    Intracellular bacterial pathogens have developed a variety of strategies to avoid degradation by the host innate immune defense mechanisms triggered upon phagocytocis. Upon infection of mammalian host cells, the intracellular pathogen Francisella replicates exclusively in the cytosolic compartment. Hence, its ability to escape rapidly from the phagosomal compartment is critical for its pathogenicity. Here, we show for the first time that a glutamate transporter of Francisella (here designated GadC) is critical for oxidative stress defense in the phagosome, thus impairing intra-macrophage multiplication and virulence in the mouse model. The gadC mutant failed to efficiently neutralize the production of reactive oxygen species. Remarkably, virulence of the gadC mutant was partially restored in mice defective in NADPH oxidase activity. The data presented highlight links between glutamate uptake, oxidative stress defense, the tricarboxylic acid cycle and phagosomal escape. This is the first report establishing the role of an amino acid transporter in the early stage of the Francisella intracellular lifecycle. PMID:24453979

  18. A microbial arsenic cycle in sediments of an acidic mine impoundment: Herman Pit, Clear Lake, California

    USGS Publications Warehouse

    Blum, Jodi S.; McCann, Shelley; Bennett, S.; Miller, Laurence G.; Stolz, J. R.; Stoneburner, B.; Saltikov, C.; Oremland, Ronald S.

    2015-01-01

    The involvement of prokaryotes in the redox reactions of arsenic occurring between its +5 [arsenate; As(V)] and +3 [arsenite; As(III)] oxidation states has been well established. Most research to date has focused upon circum-neutral pH environments (e.g., freshwater or estuarine sediments) or arsenic-rich “extreme” environments like hot springs and soda lakes. In contrast, relatively little work has been conducted in acidic environments. With this in mind we conducted experiments with sediments taken from the Herman Pit, an acid mine drainage impoundment of a former mercury (cinnabar) mine. Due to the large adsorptive capacity of the abundant Fe(III)-rich minerals, we were unable to initially detect in solution either As(V) or As(III) added to the aqueous phase of live sediment slurries or autoclaved controls, although the former consumed added electron donors (i.e., lactate, acetate, hydrogen), while the latter did not. This prompted us to conduct further experiments with diluted slurries using the live materials from the first incubation as inoculum. In these experiments we observed reduction of As(V) to As(III) under anoxic conditions and reduction rates were enhanced by addition of electron donors. We also observed oxidation of As(III) to As(V) in oxic slurries as well as in anoxic slurries amended with nitrate. We noted an acid-tolerant trend for sediment slurries in the cases of As(III) oxidation (aerobic and anaerobic) as well as for anaerobic As(V) reduction. These observations indicate the presence of a viable microbial arsenic redox cycle in the sediments of this extreme environment, a result reinforced by the successful amplification of arsenic functional genes (aioA, and arrA) from these materials.

  19. Enhancing cosmetic outcomes by combining superficial glycolic acid (alpha-hydroxy acid) peels with nonablative lasers, intense pulsed light, and trichloroacetic acid peels.

    PubMed

    Effron, Cheryl; Briden, M Elizabeth; Green, Barbara A

    2007-01-01

    Nonablative lasers, intense pulsed light (IPL), and trichloroacetic acid (TCA) peels are cosmetic rejuvenation techniques used to remodel skin and provide improved skin texture, firmness, and even pigmentation. Glycolic acid is an alpha-hydroxy acid that can be used as a topical skin peel to provide important complementary benefits to nonablative lasers, IPL, and TCA peels. Superficial glycolic acid peels provide both epidermal and dermal antiaging benefits, can be used to smooth the stratum corneum to reduce light scattering, and can enable the use of lower concentrations of TCA during a peel procedure. When used with these procedures, glycolic acid peels can enhance skin benefits and perceived patient outcomes. Methods of combining nonablative lasers, IPL, and TCA peels with glycolic acid peels were discussed at a dermatologist roundtable event and are summarized in this article. PMID:17455887

  20. Spur gears: Optimal geometry, methods for generation and Tooth Contact Analysis (TCA) program

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Zhang, Jiao

    1988-01-01

    The contents of this report include the following: (1) development of optimal geometry for crowned spur gears; (2) methods for their generation; and (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact on the crowned spur gears. The method developed for synthesis is used for the determination of the optimal geometry for crowned pinion surface and is directed to reduce the sensitivity of the gears to misalignment, localize the bearing contact, and guarantee the favorable shape and low level of the transmission errors. A new method for the generation of the crowned pinion surface has been proposed. This method is based on application of the tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The crowned pinion surface can also be generated by a generating plane whose motion is provided by an automatic grinding machine controlled by a computer. The TCA program simulates the meshing and bearing contact of the misaligned gears. The transmission errors are also determined.

  1. Topology of modified helical gears and Tooth Contact Analysis (TCA) program

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Zhang, Jiao

    1989-01-01

    The contents of this report covers: (1) development of optimal geometries for crowned helical gears; (2) a method for their generation; (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact of the crowned helical gears; and (4) modelling and simulation of gear shaft deflection. The developed method for synthesis was used to determine the optimal geometry for a crowned helical pinion surface and was directed to localize the bearing contact and guarantee favorable shape and a low level of transmission errors. Two new methods for generation of the crowned helical pinion surface are proposed. One is based on the application of a tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The other is based on a crowning pinion tooth surface with predesigned transmission errors. The pinion tooth surface can be generated by a computer-controlled automatic grinding machine. The TCA program simulates the meshing and bearing contact of the misaligned gears. The transmission errors are also determined. The gear shaft deformation was modelled and investigated. It was found that the deflection of gear shafts has the same effect as gear misalignment.

  2. Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

    NASA Astrophysics Data System (ADS)

    Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

    2014-12-01

    Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

  3. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  4. Lead acid battery performance and cycle life increased through addition of discrete carbon nanotubes to both electrodes

    NASA Astrophysics Data System (ADS)

    Sugumaran, Nanjan; Everill, Paul; Swogger, Steven W.; Dubey, D. P.

    2015-04-01

    Contemporary applications are changing the failure mechanisms of lead acid batteries. Sulfation at the negative electrode, acid stratification, and dendrite formation now precede positive electrode failures such as grid corrosion and active material shedding. To attenuate these failures, carbon has been explored as a negative electrode additive to increase charge acceptance, eliminate sulfation, and extend cycle life. Frequently, however, carbon incorporation decreases paste density and hinders manufacturability. Discrete carbon nanotubes (dCNT), also known as Molecular Rebar®, are lead acid battery additives which can be stably incorporated into either electrode to increase charge acceptance and cycle life with no change to paste density and without impeding the manufacturing process. Here, full-scale automotive batteries containing dCNT in the negative electrode or both negative and positive electrodes are compared to control batteries. dCNT batteries show little change to Reserve Capacity, improved Cold Cranking, increased charge acceptance, and enhanced overall system efficiency. Life cycle tests show >60% increases when dCNT are incorporated into the negative electrode (HRPSoC/SBA) and up to 500% when incorporated into both electrodes (SBA), with water loss per cycle reduced >20%. Failure modes of cycled batteries are discussed and a hypothesis of dCNT action is introduced: the dCNT/Had Overcharge Reaction Mechanism.

  5. SAURER REGEN, EINE FOLGE DER STOERUNG HYDROGEOCHEMISCHER KREISLAEUFE (ACID RAIN, A CONSEQUENCE OF MAN'S ALTERATION OF HYDROGEOCHEMICAL CYCLES)

    EPA Science Inventory

    The occurrence of acid precipitation in regions of the northern hemisphere results from the anthropogenic disturbance of cycles that couple land, water and atmosphere. The oxidation of C, S and N resulting mostly from fossil fuel burning rivals oxidation processes induced by phot...

  6. DIBROMOACETIC ACID-INDUCED ELEVATIONS IN CIRCULATING ESTRADIOL: EFFECTS IN BOTH CYCLING AND OVARIECTOMIZED/STEROID-PRIMED FEMALE RATS

    EPA Science Inventory

    RTD-03-031
    Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations in Circulating Estradiol: Effects in Both Cycling and Ovariectomized/Steroid-primed Female Rats. Reproductive Toxicology (in press).

    Abstract

    Oral exposures to high concentrations of th...

  7. Triglyceride accumulation and fatty acid profile changes in Chlorella (Chlorophyta) during high pH-induced cell cycle inhibition

    SciTech Connect

    Guckert, J.B.; Cooksey, K.E. )

    1990-03-01

    Alkaline pH stress resulted in triglyceride (TG) accumulation in Chlorella CHLOR1 and was independent of medium nitrogen or carbon levels. Based on morphological observations, alkaline pH inhibited autospore release, thus increasing the time for cell cycle completion. Autospore release has been postulated to coincide with TG utilization within the microalgal cell division cycle. The alkaline pH stress affected lipid accumulation by inhibiting the cell division cycle prior to autospore release and, therefore, prior to TG utilization. Cells inhibited in this manner showed an increase in TG accumulation but a decrease in both membrane lipid classes (glycolipid and polar lipid). Unlike TG fatty acid profiles, membrane lipid fatty acid profiles were not stable during TG accumulation. The membrane profiles became similar to the TG, i.e. less unsaturated than in the membrane lipids of unstressed control cells.

  8. Replication of Simian Virus 40 Deoxyribonucleic Acid: Analysis of the One-Step Growth Cycle

    PubMed Central

    Manteuil, Simone; Pages, Jacqueline; Stehelin, Dominique; Girard, Marc

    1973-01-01

    The time course of replication of simian virus 40 deoxyribonucleic acid (DNA) was investigated in growing monolayer cultures of subcloned CV1 cells. At multiplicities of infection of 30 to 60 plaque-forming units (PFU)/cell, first progeny DNA molecules (component 1) were detected by 10 hr after infection. During the following 10 to 12 hr, accumulation of virus DNA proceeded at ever increasing rates, albeit in a non-exponential fashion. The rate of synthesis then remained constant, until approximately the 40th hour postinfection, when DNA replication stopped. Under these conditions, the duration of the virus growth cycle was approximately 50 hr. The time needed for the synthesis of one DNA molecule was found to be approximately 15 min. At multiplicities of infection of 1 or less than 1 PFU/cell, the onset of the linear phase of DNA accumulation was delayed, but the final rate of DNA synthesis was the same, independent of the input multiplicity. This was taken as a proof that templates for the synthesis of viral DNA multiply in the cell during the early phase of replication. However, the probability for every replicated DNA molecule to become in turn replicative decreased constantly during that phase. This could be accounted for by assuming a limited number of replication sites in the infected cell. PMID:4346282

  9. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study

    SciTech Connect

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-15

    Highlights: • Two scenarios of acid gases removal in WTE plants were compared in an LCA study. • A detailed inventory based on primary data has been reported for the production of the new dolomitic sorbent. • Results show that the comparison between the two scenarios does not show systematic differences. • The potential impacts are reduced only if there is an increase in the energy efficiency of the WTE plant. - Abstract: The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO{sub 2} emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in

  10. Valeric acid induces cell cycle arrest at G1 phase in CHO cell cultures and improves recombinant antibody productivity.

    PubMed

    Park, Jin Hyoung; Noh, Soo Min; Woo, Ju Rang; Kim, Jong Won; Lee, Gyun Min

    2016-03-01

    To find a more effective chemical reagent for improved monoclonal antibody (mAb) production, eight chemical reagents (curcumin, quercein, DL-sulforaphane, thymidine, valeric acid, phenyl butyrate, valproic acid, and lithium chloride) known to induce cell cycle arrest were examined individually as chemical additives to recombinant CHO (rCHO) cell cultures producing mAb. Among these chemical additives, valeric acid showed the best production performance. Valeric acid decreased specific growth rate (μ), but increased culture longevity and specific mAb productivity (qmAb ) in a dose-dependent manner. The beneficial effect of valeric acid on culture longevity and qmAb outweighed its detrimental effect on μ, resulting in 2.9-fold increase in the maximum mAb concentration when 1.5 mM valeric acid was added to the cultures. Furthermore, valeric acid did not negatively affect the mAb quality attributes with regard to aggregation, charge variation, and galactosylation. Unexpectedly, galactosylation of the mAb increased by the 1.5 mM valeric acid addition. Taken together, the results obtained here demonstrate that valeric acid is an effective chemical reagent to increase mAb production in rCHO cells. PMID:26663903

  11. Phragmites australis response to Cu in terms of low molecular weight organic acids (LMWOAs) exudation: Influence of the physiological cycle

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2014-06-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere for several purposes, including in response to metal contamination. Despite this, little is yet known about the exudation of such substances from marsh plants roots in response to metal exposure. This work aimed at assessing the influence of the physiological cycle of marsh plants on the exudation of ALMWOAs in response to Cu contamination. In vitro experiments were carried out with Phragmites australis specimens, collected in different seasons. Plant roots were exposed to freshwater contaminated with two different Cu concentrations (67 μg/L and 6.9 mg/L), being the ALMWOAs released by the roots measured. Significant differences (both qualitative and quantitative) were observed during the Phragmites australis life cycle. At growing stage, Cu stimulated the exudation of oxalic and formic acids but no significant stimulation was observed for citric acid. At developing stage, exposure to Cu caused inhibition of oxalic acid exudation whereas citric acid liberation was stimulated but only in the media spiked with the lowest Cu concentration tested. At the decaying stage, no significant variation on oxalic acid was observed, whereas the citric and formic acids release increased as a consequence of the plant exposure to Cu. The physiological cycle of Phragmites australis, and probably also of other marsh plants, is therefore an important feature conditioning plants response to Cu contamination, in terms of ALMWOAs exudation. Hence this aspect should be considered when conducting studies on rhizodeposition involving marsh plants exposed to metals and in the event of using marsh plants for phytoremediation purposes in contaminated estuarine areas.

  12. Tandem dissolution of UO3 in amide-based acidic ionic liquid and in situ electrodeposition of UO2 with regeneration of the ionic liquid: a closed cycle.

    PubMed

    Wanigasekara, Eranda; Freiderich, John W; Sun, Xiao-Guang; Meisner, Roberta A; Luo, Huimin; Delmau, Lætitia H; Dai, Sheng; Moyer, Bruce A

    2016-06-21

    A closed cycle is demonstrated for the tandem dissolution and electroreduction of UO3 to UO2 with regeneration of the acidic ionic liquid. The dissolution is achieved by use of the acidic ionic liquid [DMAH][NTf2] in [EMIM][NTf2] serving as the diluent. A sequential dissolution, electroreduction, and regeneration cycle is presented. PMID:27255672

  13. Metabolism of U/sup 14/C palmitic and 1-/sup 14/C caproic acids by lettuce seeds during early germination

    SciTech Connect

    Salon, C.; Raymond, P.; Pradet, A.

    1986-04-01

    Germinating lettuce embryos (before radicule emergence) were fed with either U/sup 14/C palmitic acid or 1/sup 14/C caproic acid until a metabolic steady state was reached. The bulk of labelled caproate was evolved as respiratory CO/sub 2/ (52%) and incorporated into organic and amino acids (38%) and only a small part incorporated into lipids whereas most of labelled palmitic acid was found into lipids (92%) and only 8% evolved as CO/sub 2/ and incorporated into organic and amino acids. The label distribution at steady state in intermediates linked to the T.C.A. cycle was interpreted using a metabolic model. They found that the two fatty acids were degraded by ..beta..-oxidation and incorporated into the T.C.A. cycle as acetylCoA suggesting that ..beta..-oxidation is located in the mitochondria. The results also indicate that lipids contribute for at least 90% to the carbon supply to respiration.

  14. Design and evaluation of a downconverter based on MicroTCA.4

    NASA Astrophysics Data System (ADS)

    Gan, Nan; Liu, Rong; Ma, Xin-Peng; Chi, Yun-Long

    2016-07-01

    Modern low-level RF (LLRF) control systems of particle accelerators are designed to achieve extremely precise field amplitude and phase regulation inside the accelerating cavities. The RF field signal is usually converted to an intermediate frequency (IF) before being sampled by ADC. As the down-conversion is an important procedure of digital signal processing in LLRF system, designing a high performance and broad band downconverter compatible with various accelerators is important. In this paper, the design of a downconverter based on MicroTCA and its performance evaluation on different frequency points are presented. The major design objective of this module is a wider operating frequency range and more flexibility in application.

  15. Microbial ecology of a novel sulphur cycling consortia from AMD: implications for acid generation

    NASA Astrophysics Data System (ADS)

    Loiselle, L. M.; Norlund, K. L.; Hitchcock, A. P.; Warren, L. A.

    2009-05-01

    Recent work1 identified a novel microbial consortia consisting of two bacterial strains common to acid mine drainage (AMD) environments (autotrophic sulphur oxidizer Acidithiobacillus ferrooxidans and heterotrophic Acidiphilium spp.) in an environmental enrichment from a mine tailings lake. The two strains showed a specific spatial arrangement within an EPS macrostructure or "pod" allowing linked metabolic redox cycling of sulphur. Sulphur species characterisation of the pods using scanning transmission X-ray microscopy (STXM) indicated that autotrophic tetrathionate disproportionation by A. ferrooxidans producing colloidal elemental sulphur (S0) is coupled to heterotrophic S0 reduction by Acidiphilium spp. Geochemical modelling of the microbial sulphur reactions indicated that if they are widespread in AMD environments, then global AMD-driven CO2 liberation from mineral weathering have been overestimated by 40-90%1. Given the common co-occurrence of these two bacteria in AMD settings, the purpose of this study was to evaluate if these pods could be induced in the laboratory by pure strains and if so, whether their combined sulphur geochemistry mimicked the previous findings. Laboratory batch experiments assessed the development of pods with pure strain type cultures (A. ferrooxidans ATCC 19859 with mixotroph Acidiphilium acidophilum ATCC 738 or strict heterotroph Acp. cryptum ATCC 2158) using fluorescent in situ hybridization (FISH) imaging. The microbial sulphur geochemistry was characterized under autotrophic conditions identical to those used with the environmental AMD enrichment in which the pods were discovered. Results showed that the combined pure strain A. ferrooxidans and Acp. acidophilum form pods identical in structure to the AMD enrichment. To test the hypothesis that these pods form for mutual metabolic benefit, experiments were performed amending pure strain and AMD enrichment bacterial treatments with organic carbon and/or additional sulphur to

  16. Biostimulation induces syntrophic interactions that impact C, S and N cycling in a sediment microbial community

    PubMed Central

    Handley, Kim M; VerBerkmoes, Nathan C; Steefel, Carl I; Williams, Kenneth H; Sharon, Itai; Miller, Christopher S; Frischkorn, Kyle R; Chourey, Karuna; Thomas, Brian C; Shah, Manesh B; Long, Philip E; Hettich, Robert L; Banfield, Jillian F

    2013-01-01

    Stimulation of subsurface microorganisms to induce reductive immobilization of metals is a promising approach for bioremediation, yet the overall microbial community response is typically poorly understood. Here we used proteogenomics to test the hypothesis that excess input of acetate activates complex community functioning and syntrophic interactions among autotrophs and heterotrophs. A flow-through sediment column was incubated in a groundwater well of an acetate-amended aquifer and recovered during microbial sulfate reduction. De novo reconstruction of community sequences yielded near-complete genomes of Desulfobacter (Deltaproteobacteria), Sulfurovum- and Sulfurimonas-like Epsilonproteobacteria and Bacteroidetes. Partial genomes were obtained for Clostridiales (Firmicutes) and Desulfuromonadales-like Deltaproteobacteria. The majority of proteins identified by mass spectrometry corresponded to Desulfobacter-like species, and demonstrate the role of this organism in sulfate reduction (Dsr and APS), nitrogen fixation and acetate oxidation to CO2 during amendment. Results indicate less abundant Desulfuromonadales, and possibly Bacteroidetes, also actively contributed to CO2 production via the tricarboxylic acid (TCA) cycle. Proteomic data indicate that sulfide was partially re-oxidized by Epsilonproteobacteria through nitrate-dependent sulfide oxidation (using Nap, Nir, Nos, SQR and Sox), with CO2 fixed using the reverse TCA cycle. We infer that high acetate concentrations, aimed at stimulating anaerobic heterotrophy, led to the co-enrichment of, and carbon fixation in Epsilonproteobacteria. Results give an insight into ecosystem behavior following addition of simple organic carbon to the subsurface, and demonstrate a range of biological processes and community interactions were stimulated. PMID:23190730

  17. IRIS Toxicological Review of Trichloroacetic Acid (External Review Draft)

    EPA Science Inventory

    EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of Trichloroacetic acid (TCA) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

  18. Acidosis Drives the Reprogramming of Fatty Acid Metabolism in Cancer Cells through Changes in Mitochondrial and Histone Acetylation.

    PubMed

    Corbet, Cyril; Pinto, Adán; Martherus, Ruben; Santiago de Jesus, João Pedro; Polet, Florence; Feron, Olivier

    2016-08-01

    Bioenergetic preferences of cancer cells foster tumor acidosis that in turn leads to dramatic reduction in glycolysis and glucose-derived acetyl-coenzyme A (acetyl-CoA). Here, we show that the main source of this critical two-carbon intermediate becomes fatty acid (FA) oxidation in acidic pH-adapted cancer cells. FA-derived acetyl-CoA not only fuels the tricarboxylic acid (TCA) cycle and supports tumor cell respiration under acidosis, but also contributes to non-enzymatic mitochondrial protein hyperacetylation, thereby restraining complex I activity and ROS production. Also, while oxidative metabolism of glutamine supports the canonical TCA cycle in acidic conditions, reductive carboxylation of glutamine-derived α-ketoglutarate sustains FA synthesis. Concomitance of FA oxidation and synthesis is enabled upon sirtuin-mediated histone deacetylation and consecutive downregulation of acetyl-CoA carboxylase ACC2 making mitochondrial fatty acyl-CoA degradation compatible with cytosolic lipogenesis. Perturbations of these regulatory processes lead to tumor growth inhibitory effects further identifying FA metabolism as a critical determinant of tumor cell proliferation under acidosis. PMID:27508876

  19. 1H nuclear magnetic resonance-based extracellular metabolomic analysis of multidrug resistant Tca8113 oral squamous carcinoma cells

    PubMed Central

    WANG, HUI; CHEN, JIAO; FENG, YUN; ZHOU, WENJIE; ZHANG, JIHUA; YU, YU; WANG, XIAOQIAN; ZHANG, PING

    2015-01-01

    A major obstacle of successful chemotherapy is the development of multidrug resistance (MDR) in the cancer cells, which is difficult to reverse. Metabolomic analysis, an emerging approach that has been increasingly applied in various fields, is able to reflect the unique chemical fingerprints of specific cellular processes in an organism. The assessment of such metabolite changes can be used to identify novel therapeutic biomarkers. In the present study, 1H nuclear magnetic resonance (NMR) spectroscopy was used to analyze the extracellular metabolomic spectrum of the Tca8113 oral squamous carcinoma cell line, in which MDR was induced using the carboplatin (CBP) and pingyangmycin (PYM) chemotherapy drugs in vitro. The data were analyzed using the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) methods. The results demonstrated that the extracellular metabolomic spectrum of metabolites such as glutamate, glycerophosphoethanol amine, α-Glucose and β-Glucose for the drug-induced Tca8113 cells was significantly different from the parental Tca8113 cell line. A number of biochemicals were also significantly different between the groups based on their NMR spectra, with drug-resistant cells presenting relatively higher levels of acetate and lower levels of lactate. In addition, a significantly higher peak was observed at δ 3.35 ppm in the spectrum of the PYM-induced Tca8113 cells. Therefore, 1H NMR-based metabolomic analysis has a high potential for monitoring the formation of MDR during clinical tumor chemotherapy in the future. PMID:26137105

  20. Comparison of ultracentrifugation and density gradient separation methods for isolating Tca8113 human tongue cancer cell line-derived exosomes

    PubMed Central

    ZHANG, ZHUOYUAN; WANG, CHENXING; LI, TANG; LIU, ZHE; LI, LONGJIANG

    2014-01-01

    The aim of the present study was to compare the method of ultracentrifugation and density gradient separation for isolating Tca8113 human tongue squamous cell carcinoma cell line-derived exosomes. The exosomes were obtained from the culture supernatant of cultured Tca8113 cells, respectively, followed by identification with transmission electron microscopy observation and western blot analysis. The two different methods were then compared by the morphology, the distribution range of the particle size and the concentration of proteins of the extracted exosomes. In vitro, Tca8113 cells can secrete a large amount of vesicle-like structures, which are identified as exosomes by the presence of the surface markers, Hsp-70 and Alix. The protein profile of the two products are almost the same, however the particle size distribution of the exosomes extracted with density gradient centrifugation are more limited, between 40–120 nm, and these have a higher protein concentration. The results indicate that Tca8113 cells can secrete exosomes in vitro, and the density gradient separation methods for purifying exosomes is improved, which is helpful for future research and application of exosomes. PMID:25202395

  1. Extraction-less, rapid assay for the direct detection of 2,4,6-trichloroanisole (TCA) in cork samples.

    PubMed

    Apostolou, Theofylaktos; Pascual, Nuria; Marco, M-Pilar; Moschos, Anastassios; Petropoulos, Anastassios; Kaltsas, Grigoris; Kintzios, Spyridon

    2014-07-01

    2,4,6-trichloroanisole (TCA), the cork taint molecule, has been the target of several analytical approaches over the few past years. In spite of the development of highly efficient and sensitive tools for its detection, ranging from advanced chromatography to biosensor-based techniques, a practical breakthrough for routine cork screening purposes has not yet been realized, in part due to the requirement of a lengthy extraction of TCA in organic solvents, mostly 12% ethanol and the high detectability required. In the present report, we present a modification of a previously reported biosensor system based on the measurement of the electric response of cultured fibroblast cells membrane-engineered with the pAb78 TCA-specific antibody. Samples were prepared by macerating cork tissue and mixing it directly with the cellular biorecognition elements, without any intervening extraction process. By using this novel approach, we were able to detect TCA in just five minutes at extremely low concentrations (down to 0.2 ppt). The novel biosensor offers a number of practical benefits, including a very considerable reduction in the total assay time by one day, and a full portability, enabling its direct employment for on-site, high throughput screening of cork in the field and production facilities, without requiring any type of supporting infrastructure. PMID:24840453

  2. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    PubMed

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems. PMID:26961352

  3. Therapeutic inhibition of fatty acid oxidation in right ventricular hypertrophy: exploiting Randle’s cycle

    PubMed Central

    Fang, Yong-Hu; Piao, Lin; Hong, Zhigang; Toth, Peter T.; Marsboom, Glenn; Bache-Wiig, Peter; Rehman, Jalees

    2011-01-01

    Right ventricular hypertrophy (RVH) and RV failure are major determinants of prognosis in pulmonary hypertension and congenital heart disease. In RVH, there is a metabolic shift from glucose oxidation (GO) to glycolysis. Directly increasing GO improves RV function, demonstrating the susceptibility of RVH to metabolic intervention. However, the effects of RVH on fatty acid oxidation (FAO), the main energy source in adult myocardium, are unknown. We hypothesized that partial inhibitors of FAO (pFOXi) would indirectly increase GO and improve RV function by exploiting the reciprocal relationship between FAO and GO (Randle’s cycle). RVH was induced in adult Sprague-Dawley rats by pulmonary artery banding (PAB). pFOXi were administered orally to prevent (trimetazidine, 0.7 g/L for 8 weeks) or regress (ranolazine 20 mg/day or trimetazidine for 1 week, beginning 3 weeks post-PAB) RVH. Metabolic, hemodynamic, molecular, electrophysiologic, and functional comparisons with sham rats were performed 4 or 8 weeks post-PAB. Metabolism was quantified in RV working hearts, using a dual-isotope technique, and in isolated RV myocytes, using a Seahorse Analyzer. PAB-induced RVH did not cause death but reduced cardiac output and treadmill walking distance and elevated plasma epinephrine levels. Increased RV FAO in PAB was accompanied by increased carnitine palmitoyl-transferase expression; conversely, GO and pyruvate dehydrogenase (PDH) activity were decreased. pFOXi decreased FAO and restored PDH activity and GO in PAB, thereby increasing ATP levels. pFOXi reduced the elevated RV glycogen levels in RVH. Trimetazidine and ranolazine increased cardiac output and exercise capacity and attenuated exertional lactic acidemia in PAB. RV monophasic action potential duration and QTc interval prolongation in RVH normalized with trimetazidine. pFOXi also decreased the mild RV fibrosis seen in PAB. Maladaptive increases in FAO reduce RV function in PAB-induced RVH. pFOXi inhibit FAO, which

  4. Metabolic carbon fluxes and biosynthesis of polyhydroxyalkanoates in Ralstonia eutropha on short chain fatty acids.

    PubMed

    Yu, Jian; Si, Yingtao

    2004-01-01

    Short chain fatty acids such as acetic, propionic, and butyric acids can be synthesized into polyhydroxyalkanoates (PHAs) by Ralstonia eutropha. Metabolic carbon fluxes of the acids in living cells have significant effect on the yield, composition, and thermomechanical properties of PHA bioplastics. Based on the general knowledge of central metabolism pathways and the unusual metabolic pathways in R. eutropha, a metabolic network of 41 bioreactions is constructed to analyze the carbon fluxes on utilization of the short chain fatty acids. In fed-batch cultures with constant feeding of acid media, carbon metabolism and distribution in R. eutropha were measured involving CO2, PHA biopolymers, and residual cell mass. As the cells underwent unsteady state metabolism and PHA biosynthesis under nitrogen-limited conditions, accumulative carbon balance was applied for pseudo-steady-state analysis of the metabolic carbon fluxes. Cofactor NADP/NADPH balanced between PHA synthesis and the C3/C4 pathway provided an independent constraint for solution of the underdetermined metabolic network. A major portion of propionyl-CoA was directed to pyruvate via the 2-methylcitrate cycle and further decarboxylated to acetyl-CoA. Only a small amount of propionate carbon (<15% carbon) was directly condensed with acetyl-CoA for 3-hydroxyvalerate. The ratio of glyoxylate shunt to TCA cycle varies from 0 to 0.25, depending on the intracellular acetyl-CoA level and acetic acid in the medium. Malate is the node of the C3/C4 pathway and TCA cycle and its decarboxylation to dehydrogenation ranges from 0.33 to 1.28 in response to the demands on NADPH and oxaloacetate for short chain fatty acids utilization. PMID:15296425

  5. Quantifying Rates of Complete Microbial Iron Redox Cycling in Acidic Hot Springs

    NASA Astrophysics Data System (ADS)

    St Clair, B.; Pottenger, J. W.; Shock, E.

    2013-12-01

    concentrations of ferrous iron. Experimental design allowed us to measure biological and abiological rates independently. Results indicate a relatively consistent rate of biological iron oxidation between 20-100 ng Fe2+(gm wet sediment)-1 (second)-1 where oxide accumulations occur. Abiological oxidation rates increase significantly with increasing pH, and greatly limit soluble ferrous iron above a pH of 3.5 at high temperatures. Rates of biological iron reduction are typically comparable to oxidation, and can often double oxidation rates when supplemented with organic carbon. Abiological iron reduction rates are inconsequential when the pH is greater than 2, but increase sharply below this point. Results indicate that comparable rates of microbial oxidation and reduction are common in springs where biogenic iron oxide accumulates. It appears that the interplay of temperature, oxygen availability, and supply of organic carbon determines the extent and history of iron oxide accumulation. Taken together, our results show that complete microbial iron redox cycles are active in acidic hot springs wherever biogenic iron oxides accumulate.

  6. Amphipathic β2,2-Amino Acid Derivatives Suppress Infectivity and Disrupt the Intracellular Replication Cycle of Chlamydia pneumoniae

    PubMed Central

    Tiirola, Terttu M.; Strøm, Morten B.; Vuorela, Pia M.

    2016-01-01

    We demonstrate in the current work that small cationic antimicrobial β2,2-amino acid derivatives (Mw < 500 Da) are highly potent against Chlamydia pneumoniae at clinical relevant concentrations (< 5 μM, i.e. < 3.4 μg/mL). C. pneumoniae is an atypical respiratory pathogen associated with frequent treatment failures and persistent infections. This gram-negative bacterium has a biphasic life cycle as infectious elementary bodies and proliferating reticulate bodies, and efficient treatment is challenging because of its long and obligate intracellular replication cycle within specialized inclusion vacuoles. Chlamydicidal effect of the β2,2-amino acid derivatives in infected human epithelial cells was confirmed by transmission electron microscopy. Images of infected host cells treated with our lead derivative A2 revealed affected chlamydial inclusion vacuoles 24 hours post infection. Only remnants of elementary and reticulate bodies were detected at later time points. Neither the EM studies nor resazurin-based cell viability assays showed toxic effects on uninfected host cells or cell organelles after A2 treatment. Besides the effects on early intracellular inclusion vacuoles, the ability of these β2,2-amino acid derivatives to suppress Chlamydia pneumoniae infectivity upon treatment of elementary bodies suggested also a direct interaction with bacterial membranes. Synthetic β2,2-amino acid derivatives that target C. pneumoniae represent promising lead molecules for development of antimicrobial agents against this hard-to-treat intracellular pathogen. PMID:27280777

  7. Tandem dissolution of UO 3 in amide-based acidic ionic liquid and in situ electrodeposition of UO 2 with regeneration of the ionic liquid: a closed cycle

    DOE PAGESBeta

    Wanigasekara, Eranda; Freiderich, John W.; Sun, Xiao-Guang; Meisner, Roberta A.; Luo, Huimin; Delmau, Lætitia H.; Dai, Sheng; Moyer, Bruce A.

    2016-05-19

    A closed cycle is demonstrated for the tandem dissolution and electroreduction of UO3 to UO2 with regeneration of the acidic ionic liquid. The dissolution is achieved by use of the acidic ionic liquid N,N-dimethylacetimidium bis(trifluoromethanesulfonimide) in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonimide) serving as the diluent. Bulk electrolysis performed at 1.0 V vs. Ag reference yields a dark brown-black uranium deposit (UO2) on the cathode. Anodic oxidation of water in the presence of dimethylacetamide regenerates the acidic ionic liquid. We have demonstrated the individual steps in the cycle together with a sequential dissolution, electroreduction, and regeneration cycle.

  8. SWATCH: common control SW for the uTCA-based upgraded CMS L1 Trigger

    NASA Astrophysics Data System (ADS)

    Brooke, Jim; Bunkowski, Karol; Cali, Ivan; Ghabrous Larrea, Carlos; Lazaridis, Christos; Thea, Alessandro

    2015-12-01

    The CMS L1 Trigger electronics are composed of a large number of different cards based on the VMEBus standard. The majority of the system is being replaced to adapt the trigger to the higher collision rates the LHC will deliver after the LS1, the first phase on the CMS upgrade program. As a consequence, the software that controls, monitors and tests the hardware will need to be re-written. The upgraded trigger will consist of a set of general purpose boards of similar technology that follow the TCA specification, thus resulting in a more homogeneous system. A great effort has been made to identify the common firmware blocks and components shared across different cards, regardless of the role they play within the trigger data path. A similar line of work has been followed in order to identify all possible common functionalities in the control software, as well as in the database where the hardware initialisation and configuration data are stored. This will not only increase the homogeneity on the software and database sides, but it will also reduce the manpower needed to accommodate the online SW to the changes on hardware. Due to the fact that the upgrade will take place in different stages, it has been taken into consideration that these new components had to be integrated in the current SW framework. This paper presents the design of the control SW and configuration database for the upgraded L1 Trigger.

  9. Prevention of cardiolipin oxidation and fatty acid cycling as two antioxidant mechanisms of cationic derivatives of plastoquinone (SkQs).

    PubMed

    Skulachev, Vladimir P; Antonenko, Yury N; Cherepanov, Dmitry A; Chernyak, Boris V; Izyumov, Denis S; Khailova, Ludmila S; Klishin, Sergey S; Korshunova, Galina A; Lyamzaev, Konstantin G; Pletjushkina, Olga Yu; Roginsky, Vitaly A; Rokitskaya, Tatiana I; Severin, Fedor F; Severina, Inna I; Simonyan, Ruben A; Skulachev, Maxim V; Sumbatyan, Natalia V; Sukhanova, Evgeniya I; Tashlitsky, Vadim N; Trendeleva, Tatyana A; Vyssokikh, Mikhail Yu; Zvyagilskaya, Renata A

    2010-01-01

    The present state of the art in studies on the mechanisms of antioxidant activities of mitochondria-targeted cationic plastoquinone derivatives (SkQs) is reviewed. Our experiments showed that these compounds can operate as antioxidants in two quite different ways, i.e. (i) by preventing peroxidation of cardiolipin [Antonenko et al., Biochemistry (Moscow) 73 (2008) 1273-1287] and (ii) by fatty acid cycling resulting in mild uncoupling that inhibits the formation of reactive oxygen species (ROS) in mitochondrial State 4 [Severin et al. Proc. Natl. Acad. Sci. USA 107 (2009), 663-668]. The quinol and cationic moieties of SkQ are involved in cases (i) and (ii), respectively. In case (i) SkQH2 interrupts propagation of chain reactions involved in peroxidation of unsaturated fatty acid residues in cardiolipin, the formed SkQ- being reduced back to SkQH2 by heme bH of complex III in an antimycin-sensitive way. Molecular dynamics simulation showed that there are two stable conformations of SkQ1 with the quinol residue localized near peroxyl radicals at C9 or C13 of the linoleate residue in cardiolipin. In mechanism (ii), fatty acid cycling mediated by the cationic SkQ moiety is involved. It consists of (a) transmembrane movement of the fatty acid anion/SkQ cation pair and (b) back flows of free SkQ cation and protonated fatty acid. The cycling results in a protonophorous effect that was demonstrated in planar phospholipid membranes and liposomes. In mitochondria, the cycling gives rise to mild uncoupling, thereby decreasing membrane potential and ROS generation coupled to reverse electron transport in the respiratory chain. In yeast cells, dodecyltriphenylphosphonium (capital ES, Cyrillic12TPP), the cationic part of SkQ1, induces uncoupling that is mitochondria-targeted since capital ES, Cyrillic12TPP is specifically accumulated in mitochondria and increases the H+ conductance of their inner membrane. The conductance of the outer cell membrane is not affected by capital ES

  10. Metabolomics approach to assessing plasma 13- and 9-hydroxy-octadecadienoic acid and linoleic acid metabolite responses to 75-km cycling.

    PubMed

    Nieman, David C; Shanely, R Andrew; Luo, Beibei; Meaney, Mary Pat; Dew, Dustin A; Pappan, Kirk L

    2014-07-01

    Bioactive oxidized linoleic acid metabolites (OXLAMs) include 13- and 9-hydroxy-octadecadienoic acid (13-HODE + 9-HODE) and have been linked to oxidative stress, inflammation, and numerous pathological and physiological states. The purpose of this study was to measure changes in plasma 13-HODE + 9-HODE following a 75-km cycling bout and identify potential linkages to linoleate metabolism and established biomarkers of oxidative stress (F2-isoprostanes) and inflammation (cytokines) using a metabolomics approach. Trained male cyclists (N = 19, age 38.0 ± 1.6 yr, wattsmax 304 ± 10.5) engaged in a 75-km cycling time trial on their own bicycles using electromagnetically braked cycling ergometers (2.71 ± 0.07 h). Blood samples were collected preexercise, immediately post-, 1.5 h post-, and 21 h postexercise, and analyzed for plasma cytokines (IL-6, IL-8, IL-10, tumor necrosis factor-α, monocyte chemoattractant protein-1, granulocyte colony-stimulating factor), F2-isoprostanes, and shifts in metabolites using global metabolomics procedures with gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS). 13-HODE + 9-HODE increased 3.1-fold and 1.7-fold immediately post- and 1.5 h postexercise (both P < 0.001) and returned to preexercise levels by 21-h postexercise. Post-75-km cycling plasma levels of 13-HODE + 9-HODE were not significantly correlated with increases in plasma cytokines but were positively correlated with postexercise F2-isoprostanes (r = 0.75, P < 0.001), linoleate (r = 0.54, P = 0.016), arachidate (r = 0.77, P < 0.001), 12,13-dihydroxy-9Z-octadecenoate (12,13-DiHOME) (r = 0.60, P = 0.006), dihomo-linolenate (r = 0.57, P = 0.011), and adrenate (r = 0.56, P = 0.013). These findings indicate that prolonged and intensive exercise caused a transient, 3.1-fold increase in the stable linoleic acid oxidation product 13-HODE + 9-HODE and was related to increases in F2-isoprostanes, linoleate, and fatty acids in the linoleate

  11. The influence of alternative pathways of respiration that utilize branched-chain amino acids following water shortage in Arabidopsis.

    PubMed

    Pires, Marcel V; Pereira Júnior, Adilson A; Medeiros, David B; Daloso, Danilo M; Pham, Phuong Anh; Barros, Kallyne A; Engqvist, Martin K M; Florian, Alexandra; Krahnert, Ina; Maurino, Veronica G; Araújo, Wagner L; Fernie, Alisdair R

    2016-06-01

    During dark-induced senescence isovaleryl-CoA dehydrogenase (IVDH) and D-2-hydroxyglutarate dehydrogenase (D-2HGDH) act as alternate electron donors to the ubiquinol pool via the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) pathway. However, the role of this pathway in response to other stresses still remains unclear. Here, we demonstrated that this alternative pathway is associated with tolerance to drought in Arabidopsis. In comparison with wild type (WT) and lines overexpressing D-2GHDH, loss-of-function etfqo-1, d2hgdh-2 and ivdh-1 mutants displayed compromised respiration rates and were more sensitive to drought. Our results demonstrated that an operational ETF/ETFQO pathway is associated with plants' ability to withstand drought and to recover growth once water becomes replete. Drought-induced metabolic reprogramming resulted in an increase in tricarboxylic acid (TCA) cycle intermediates and total amino acid levels, as well as decreases in protein, starch and nitrate contents. The enhanced levels of the branched-chain amino acids in loss-of-function mutants appear to be related to their increased utilization as substrates for the TCA cycle under water stress. Our results thus show that mitochondrial metabolism is highly active during drought stress responses and provide support for a role of alternative respiratory pathways within this response. PMID:26616144

  12. Maintenance carbon cycle in crassulacean Acid metabolism plant leaves : source and compartmentation of carbon for nocturnal malate synthesis.

    PubMed

    Kenyon, W H; Severson, R F; Black, C C

    1985-01-01

    The reciprocal relationship between diurnal changes in organic acid and storage carbohydrate was examined in the leaves of three Crassulacean acid metabolism plants. It was found that depletion of leaf hexoses at night was sufficient to account quantitatively for increase in malate in Ananas comosus but not in Sedum telephium or Kalanchoë daigremontiana. Fructose and to a lesser extent glucose underwent the largest changes. Glucose levels in S. telephium leaves oscillated diurnally but were not reciprocally related to malate fluctuations.Analysis of isolated protoplasts and vacuoles from leaves of A. comosus and S. telephium revealed that vacuoles contain a large percentage (>50%) of the protoplast glucose, fructose and malate, citrate, isocitrate, ascorbate and succinate. Sucrose, a major constituent of intact leaves, was not detectable or was at extremely low levels in protoplasts and vacuoles from both plants.In isolated vacuoles from both A. comosus and S. telephium, hexose levels decreased at night at the same time malate increased. Only in A. comosus, however, could hexose metabolism account for a significant amount of the nocturnal increase in malate. We conclude that, in A. comosus, soluble sugars are part of the daily maintenance carbon cycle and that the vacuole plays a dynamic role in the diurnal carbon assimilation cycle of this Crassulacean acid metabolism plant. PMID:16664005

  13. Pt/TiO2 (Rutile) Catalysts for Sulfuric Acid Decomposition in Sulfur-Based Thermochemical Water-Splitting Cycles

    SciTech Connect

    L. M. Petkovic; D. M. Ginosar; H. W. Rollins; K. C. Burch; P. J. Pinhero; H. H. Farrell

    2008-04-01

    Thermochemical cycles consist of a series of chemical reactions to produce hydrogen from water at lower temperatures than by direct thermal decomposition. All the sulfur-based cycles for water splitting employ the sulfuric acid decomposition reaction. This work reports the studies performed on platinum supported on titania (rutile) catalysts to investigate the causes of catalyst deactivation under sulfuric acid decomposition reaction conditions. Samples of 1 wt% Pt/TiO2 (rutile) catalysts were submitted to flowing concentrated sulfuric acid at 1123 K and atmospheric pressure for different times on stream (TOS) between 0 and 548 h. Post-operation analyses of the spent catalyst samples showed that Pt oxidation and sintering occurred under reaction conditions and some Pt was lost by volatilization. Pt loss rate was higher at initial times but total loss appeared to be independent of the gaseous environment. Catalyst activity showed an initial decrease that lasted for about 66 h, followed by a slight recovery of activity between 66 and 102 h TOS, and a period of slower deactivation after 102 h TOS. Catalyst sulfation did not seem to be detrimental to catalyst activity and the activity profile suggested that a complex dynamical situation involving platinum sintering, volatilization, and oxidation, along with TiO2 morphological changes affected catalyst activity in a non-monotonic way.

  14. Determining Multiple Responses of Pseudomonas aeruginosa PAO1 to an Antimicrobial Agent, Free Nitrous Acid.

    PubMed

    Gao, Shu-Hong; Fan, Lu; Peng, Lai; Guo, Jianhua; Agulló-Barceló, Míriam; Yuan, Zhiguo; Bond, Philip L

    2016-05-17

    Free nitrous acid (FNA) has recently been demonstrated as an antimicrobial agent on a range of micro-organisms, especially in wastewater-treatment systems. However, the antimicrobial mechanism of FNA is largely unknown. Here, we report that the antimicrobial effects of FNA are multitargeted. The response of a model denitrifier, Pseudomnas aeruginosa PAO1 (PAO1), common in wastewater treatment, was investigated in the absence and presence of inhibitory level of FNA (0.1 mg N/L) under anaerobic denitrifying conditions. This was achieved through coupling gene expression analysis, by RNA sequencing, and with a suite of physiological analyses. Various transcripts exhibited significant changes in abundance in the presence of FNA. Respiration was likely inhibited because denitrification activity was severely depleted, and decreased transcript levels of most denitrification genes occurred. As a consequence, the tricarboxylic acid (TCA) cycle was inhibited due to the lowered cellular redox state in the FNA-exposed cultures. Meanwhile, during FNA exposure, PAO1 rerouted its carbon metabolic pathway from the TCA cycle to pyruvate fermentation with acetate as the end product as a possible survival mechanism. Additionally, protein synthesis was significantly decreased, and ribosome preservation was evident. These findings improve our understanding of PAO1 in response to FNA and contribute toward the potential application for use of FNA as an antimicrobial agent. PMID:27116299

  15. Reversal of metabolic deficits by lipoic acid in a triple transgenic mouse model of Alzheimer's disease: a 13C NMR study.

    PubMed

    Sancheti, Harsh; Kanamori, Keiko; Patil, Ishan; Díaz Brinton, Roberta; Ross, Brian D; Cadenas, Enrique

    2014-02-01

    Alzheimer's disease is an age-related neurodegenerative disease characterized by deterioration of cognition and loss of memory. Several clinical studies have shown Alzheimer's disease to be associated with disturbances in glucose metabolism and the subsequent tricarboxylic acid (TCA) cycle-related metabolites like glutamate (Glu), glutamine (Gln), and N-acetylaspartate (NAA). These metabolites have been viewed as biomarkers by (a) assisting early diagnosis of Alzheimer's disease and (b) evaluating the efficacy of a treatment regimen. In this study, 13-month-old triple transgenic mice (a mouse model of Alzheimer's disease (3xTg-AD)) were given intravenous infusion of [1-(13)C]glucose followed by an ex vivo (13)C NMR to determine the concentrations of (13)C-labeled isotopomers of Glu, Gln, aspartate (Asp), GABA, myo-inositol, and NAA. Total ((12)C+(13)C) Glu, Gln, and Asp were quantified by high-performance liquid chromatography to calculate enrichment. Furthermore, we examined the effects of lipoic acid in modulating these metabolites, based on its previously established insulin mimetic effects. Total (13)C labeling and percent enrichment decreased by ∼50% in the 3xTg-AD mice. This hypometabolism was partially or completely restored by lipoic acid feeding. The ability of lipoic acid to restore glucose metabolism and subsequent TCA cycle-related metabolites further substantiates its role in overcoming the hypometabolic state inherent in early stages of Alzheimer's disease. PMID:24220168

  16. Incomplete tricarboxylic acid cycle in a type I methylotroph, Methylococcus capsulatus.

    PubMed Central

    Patel, R; Hoare, L; Hoare, D S; Taylor, B F

    1975-01-01

    Alpha-Ketoglutaratedehydrogenase was undetectable in extracts of Methylococcus capsulatus. Cells incorporated [1-14-C] acetate into only four protein amino acids (glutamate, proline, arginine, and leucine) and the C5, but not C1, of glutamate. PMID:806581

  17. ENERGY EFFICIENCY LIMITS FOR A RECUPERATIVE BAYONET SULFURIC ACID DECOMPOSITION REACTOR FOR SULFUR CYCLE THERMOCHEMICAL HYDROGEN PRODUCTION

    SciTech Connect

    Gorensek, M.; Edwards, T.

    2009-06-11

    A recuperative bayonet reactor design for the high-temperature sulfuric acid decomposition step in sulfur-based thermochemical hydrogen cycles was evaluated using pinch analysis in conjunction with statistical methods. The objective was to establish the minimum energy requirement. Taking hydrogen production via alkaline electrolysis with nuclear power as the benchmark, the acid decomposition step can consume no more than 450 kJ/mol SO{sub 2} for sulfur cycles to be competitive. The lowest value of the minimum heating target, 320.9 kJ/mol SO{sub 2}, was found at the highest pressure (90 bar) and peak process temperature (900 C) considered, and at a feed concentration of 42.5 mol% H{sub 2}SO{sub 4}. This should be low enough for a practical water-splitting process, even including the additional energy required to concentrate the acid feed. Lower temperatures consistently gave higher minimum heating targets. The lowest peak process temperature that could meet the 450-kJ/mol SO{sub 2} benchmark was 750 C. If the decomposition reactor were to be heated indirectly by an advanced gas-cooled reactor heat source (50 C temperature difference between primary and secondary coolants, 25 C minimum temperature difference between the secondary coolant and the process), then sulfur cycles using this concept could be competitive with alkaline electrolysis provided the primary heat source temperature is at least 825 C. The bayonet design will not be practical if the (primary heat source) reactor outlet temperature is below 825 C.

  18. TCA1, a single nuclear-encoded translational activator specific for petA mRNA in Chlamydomonas reinhardtii chloroplast.

    PubMed Central

    Wostrikoff, K; Choquet, Y; Wollman, F A; Girard-Bascou, J

    2001-01-01

    We isolated seven allelic nuclear mutants of Chlamydomonas reinhardtii specifically blocked in the translation of cytochrome f, a major chloroplast-encoded subunit of the photosynthetic electron transport chain encoded by the petA gene. We recovered one chloroplast suppressor in which the coding region of petA was now expressed under the control of a duplicated 5' untranslated region from another open reading frame of presently unknown function. Since we also recovered 14 nuclear intragenic suppressors, we ended up with 21 alleles of a single nuclear gene we called TCA1 for translation of cytochrome b(6)f complex petA mRNA. The high number of TCA1 alleles, together with the absence of genetic evidence for other nuclear loci controlling translation of the chloroplast petA gene, strongly suggests that TCA1 is the only trans-acting factor. We studied the assembly-dependent regulation of cytochrome f translation--known as the CES process--in TCA1-mutated contexts. In the presence of a leaky tca1 allele, we observed that the regulation of cytochrome f translation was now exerted within the limits of the restricted translational activation conferred by the altered version of TCA1 as predicted if TCA1 was the ternary effector involved in the CES process. PMID:11560891

  19. Power Effects on High Lift, Stability and Control Characteristics of the TCA Model Tested in the LaRC 14 x 22 Ft Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Glessner, Paul T.

    1999-01-01

    The TCA-2 wind-tunnel test was the second in a series of planned tests utilizing the 5% Technology Concept Airplane (TCA) model. Each of the tests was planned to utilize the unique capabilities of the NASA Langley 14'x22' and the NASA Ames 12' test facilities, in order to assess specific aspects of the high lift and stability and control characteristics of the TCA configuration. However, shortly after the completion of the TCA-1 test, an early projection of the Technology Configuration (TC) identified the need for several significant changes to the baseline TCA configuration. These changes were necessary in order to meet more stringent noise certification levels, as well as, to provide a means to control dynamic structural modes. The projected changes included a change to the outboard wing (increased aspect ratio and lower sweep) and a reconfiguration of the longitudinal control surfaces to include a medium size canard and a reduced horizontal tail. The impact of these proposed changes did not affect the TCA-2 test, because it was specifically planned to address power effects on the empennage and a smaller horizontal tail was in the plan to be tested. However, the focus of future tests was reevaluated and the emphasis was shifted away from assessment of TCA specific configurations to a more general assessment of configurations that encompass the projected design space for the TC.

  20. Recent new additives for electric vehicle lead-acid batteries for extending the cycle life and capacity

    SciTech Connect

    Kozawa, A.; Sato, A.; Fujita, K.; Brodd, D.

    1997-12-01

    An electrochemically prepared colloidal graphite was found to be an excellent additive for lead-acid batteries. The new additive extends the capacity and cycle life of new and old batteries and can regenerate old, almost dead, batteries. The colloidal graphite is stable in aqueous solution and the extremely fine particles are adsorbed mainly on the positive electrode. This additive has been given the name, {alpha}-Pholon. The amount required is very small: only 6% to 10% of volume of the {alpha}-Pholon solution (about 2% colloidal graphite in water solution). The beneficial effect of the new additive was demonstrated with motorcycle batteries and forklift batteries.

  1. Partial Life-Cycle and Acute Toxicity of Perfluoroalkyl Acids to Freshwater Mussels

    EPA Science Inventory

    Freshwater mussels are among the most sensitive aquatic organisms to many contaminants and have complex life-cycles that include several distinct life stages with unique contaminant exposure pathways. Standard acute (24–96 h) and chronic (28 d) toxicity tests with free larva (glo...

  2. Studies on the increase in serum concentrations of urea cycle amino acids among subjects exposed to cadmium

    SciTech Connect

    Nishino, H.; Shiroishi, K. ); Kagamimori, S.; Naruse, Y. ); Watanabe, M. )

    1988-05-01

    Itai-itai disease (I disease) is a combination of renal tubular damage and osteomalacia accompanied by osteoporosis among subjects exposed to cadmium (Cd). When the renal tubular damage progresses, the excretion of amino acids, especially, threonine, hydroxyproline, proline, citrulline, ornithine, arginine, etc. increase in urine. It was reported that the increase in urinary excretion of citrulline, arginine and ornithine may be associated with an inhibition of urea synthesis in the urea cycle. The authors have found that serum citrulline, arginine and ornithine also increased in I disease patients. In order to investigate the mechanism of the increase in these serum amino acids, comparative studies were performed using both healthy subjects and patients with renal disease as control groups.

  3. Studies on the increase in serum concentrations of urea cycle amino acids among subjects exposed to cadmium

    SciTech Connect

    Nishino, H.; Shiroishi, K.; Kagamimori, S.; Naruse, Y.; Watanabe, M.

    1988-04-01

    Itai-itai disease (I disease) is a combination of renal tubular damage and osteomalacia accompanied by osteoporosis among subjects exposed to cadmium (Cd). When the renal tubular damage progresses, the excretion of amino acids, especially, threonine, hydroxyproline, proline, citrulline, ornithine, arginine increased in urine. It has been reported that the increase in urinary excretion of citrulline, arginine and ornithine may be associated with an inhibition of urea synthesis in the urea cycle. The authors have found that serum citrulline, arginine and ornithine also increased in I disease patients. In order to investigate the mechanism of the increase in these serum amino acids, comparative studies were performed using both healthy subjects and patients with renal disease as control groups.

  4. Carglumic acid: a second look. Confirmed progress in a rare urea cycle disorder.

    PubMed

    2008-04-01

    (1) N-acetylglutamate synthase deficiency is a rare congenital disorder that causes hyperammonaemic comas, resulting in severe neurological morbidity and usually leading to death during childhood. (2) Carglumic acid is the first drug to be used for replacement therapy. Data available in 2003 showed beneficial effects on growth and psychomotor development. (3) In 2007, about 20 patients treated with carglumic acid for N-acetyglutamate synthase deficiency, for at least 5 years in half of cases, were all still alive. Their development was normal when treatment was initiated before complications occurred. (4) No serious adverse effects have been observed. (5) In practice, although this treatment has to continue for life, carglumic acid represents a major advance for patients with N-acetylglutamate synthase deficiency. PMID:18516804

  5. Relationship between extracellular enzymes and cell growth during the cell cycle of the fission yeast Schizosaccharomyces pombe: acid phosphatase.

    PubMed Central

    Miyata, M; Miyata, H

    1978-01-01

    By using the intact cells of the fission yeast Schizosaccharomyces pombe, the activity of acid phosphatase (EC 3.1.3.2) was compared through the cell cycle with the growth in cell length as a measure of cell growth. The cells of a growing asynchronous culture increased exponentially in number and in total enzyme activity, but remained constant in average length and in specific activity, In a synchronous culture prepared by selection or by induction, the specific activity was periodic in parallel with the increase in average cell length. When hydroxyurea was added to an asynchronous or a synchronous culture by selection, both specific and total activity followed the same continuous pattern as the growth in cell length after the stoppage of cell division. When oversized cells produced by a hydroxyurea pulse treatment to the culture previously syndronized by selection were transferred to a poor medium, they divided synchronously but could hardly grow in the total cell length. In this experimental situation, the total enzyme activity also scarcely increased through three division cycles. These results suggested that the increase in acid phosphatase in dependent on cell elongation. PMID:711673

  6. Using Phospholipids and Stable Carbon Isotopes to Assess Microbial Community Structures and Carbon Cycle Pathways in Kamchatka Hot Springs

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Romanek, C. S.; Burgess, E. A.; Wiegel, J.; Mills, G.; Zhang, C. L.

    2006-12-01

    Phospholipid fatty acid (PLFA) and stable carbon isotopes were used to assess the microbial community structures in Kamchatka hot springs. Eighteen mats or surface sediments were collected from hot springs having temperatures of 31 to 91°C and pHs of 4.9 to 8.5. These samples were clearly separated into three groups according to the bacterial PLFA: 1) those dominated by terminally branched odd-numbered fatty acids, 2) those dominated by C18:1 and 3) those dominated by C20:1. With support from other minor PLFA components, group 2 may be used as biomarkers for Chloroflexales or other phototrophic bacteria and group 3 for Aquificales, respectively. Among the sampled hot springs, the Arkashin pool represents the simplest microbial structure with members of Aquificales being the dominant primary producers. On the other hand, the Zavarzin pool may represent the most heterogeneous pool that may include members of Chloroflexales and Aquificales as primary producers. Bacterial 16S rDNA clone libraries confirmed the presence of these microbial groups in the two pools. Results of stable carbon isotope fractionation between CO2 source, bulk biomass and total PLFA showed that primary producers in the Arkashin pool primarily used the reductive tricarboxylic acid (rTCA) cycle (e.g., members of Aquificales); whereas the Zavarzin pool may be a mixture of the 3-hydroxypropionate (3-HP) pathway (e.g. members of Chloroflexales) and the rTCA cycle. Bacterial contribution using the Calvin cycle was not significant and may be less important in Kamchatka hot springs.

  7. Sulfur amino acid deficiency upregulates intestinal methionine cycle activity and suppresses epithelial growth in neonatal pigs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently showed that the developing gut is a significant site of methionine transmethylation to homocysteine and transsulfuration to cysteine. We hypothesized that sulfur amino acid (SAA) deficiency would preferentially reduce mucosal growth and antioxidant function in neonatal pigs. Neonatal pi...

  8. USE OF THE COMPOSITION AND STABLE CARBONIISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING

    EPA Science Inventory

    We use measurements of the concentration and stable carbon isotopic ratio (*13C) of individual microbial phospholipid fatty acids (PLFAs) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SOM) cy...

  9. A systematic analysis of TCA Escherichia coli mutants reveals suitable genetic backgrounds for enhanced hydrogen and ethanol production using glycerol as main carbon source.

    PubMed

    Valle, Antonio; Cabrera, Gema; Muhamadali, Howbeer; Trivedi, Drupad K; Ratray, Nicholas J W; Goodacre, Royston; Cantero, Domingo; Bolivar, Jorge

    2015-09-01

    Biodiesel has emerged as an environmentally friendly alternative to fossil fuels; however, the low price of glycerol feed-stocks generated from the biodiesel industry has become a burden to this industry. A feasible alternative is the microbial biotransformation of waste glycerol to hydrogen and ethanol. Escherichia coli, a microorganism commonly used for metabolic engineering, is able to biotransform glycerol into these products. Nevertheless, the wild type strain yields can be improved by rewiring the carbon flux to the desired products by genetic engineering. Due to the importance of the central carbon metabolism in hydrogen and ethanol synthesis, E. coli single null mutant strains for enzymes of the TCA cycle and other related reactions were studied in this work. These strains were grown anaerobically in a glycerol-based medium and the concentrations of ethanol, glycerol, succinate and hydrogen were analysed by HPLC and GC. It was found that the reductive branch is the more relevant pathway for the aim of this work, with malate playing a central role. It was also found that the putative C4-transporter dcuD mutant improved the target product yields. These results will contribute to reveal novel metabolic engineering strategies for improving hydrogen and ethanol production by E. coli. PMID:26058953

  10. Aristolochic acid-induced apoptosis and G2 cell cycle arrest depends on ROS generation and MAP kinases activation.

    PubMed

    Romanov, Victor; Whyard, Terry C; Waltzer, Wayne C; Grollman, Arthur P; Rosenquist, Thomas

    2015-01-01

    Ingestion of aristolochic acids (AAs) contained in herbal remedies results in a renal disease and, frequently, urothelial malignancy. The genotoxicity of AA in renal cells, including mutagenic DNA adducts formation, is well documented. However, the mechanisms of AA-induced tubular atrophy and renal fibrosis are largely unknown. To better elucidate some aspects of this process, we studied cell cycle distribution and cell survival of renal epithelial cells treated with AAI at low and high doses. A low dose of AA induces cell cycle arrest in G2/M phase via activation of DNA damage checkpoint pathway ATM-Chk2-p53-p21. DNA damage signaling pathway is activated more likely via increased production of reactive oxygen species (ROS) caused by AA treatment then via DNA damage induced directly by AA. Higher AA concentration induced cell death partly via apoptosis. Since mitogen-activated protein kinases play an important role in cell survival, death and cell cycle progression, we assayed their function in AA-treated renal tubular epithelial cells. ERK1/2 and p38 but not JNK were activated in cells treated with AA. In addition, pharmacological inhibition of ERK1/2 and p38 as well as suppression of ROS generation with N-acetyl-L-cysteine resulted in the partial relief of cells from G2/M checkpoint and a decline of apoptosis level. Cell cycle arrest may be a mechanism for DNA repair, cell survival and reprogramming of epithelial cells to the fibroblast type. An apoptosis of renal epithelial cells at higher AA dose might be necessary to provide space for newly reprogrammed fibrotic cells. PMID:24792323

  11. Genome wide response to dietary tetradecylthioacetic acid supplementation in the heart of Atlantic Salmon (Salmo salar L)

    PubMed Central

    2012-01-01

    Background Under-dimensioned hearts causing functional problems are associated with higher mortality rates in intensive Atlantic salmon aquaculture. Previous studies have indicated that tetradecylthioacetic acid (TTA) induces cardiac growth and also stimulates transcription of peroxisome proliferator activated receptors (PPAR) αand βin the Atlantic salmon heart. Since cardiac and transcriptional responses to feed are of high interest in aquaculture, the objective of this study was to characterize the transcriptional mechanisms induced by TTA in the heart of Atlantic salmon. Results Atlantic salmon were kept at sea for 17 weeks. During the first 8 weeks the fish received a TTA supplemented diet. Using microarrays, profound transcriptional effects were observed in the heart at the end of the experiment, 9 weeks after the feeding of TTA stopped. Approximately 90% of the significant genes were expressed higher in the TTA group. Hypergeometric testing revealed the over-representation of 35 gene ontology terms in the TTA fed group. The GO terms were generally categorized into cardiac performance, lipid catabolism, glycolysis and TCA cycle. Conclusions Our results indicate that TTA has profound effects on cardiac performance based on results from microarray and qRT-PCR analysis. The gene expression profile favors a scenario of ”physiological”lright hypertrophy recognized by increased oxidative fatty acid metabolism, glycolysis and TCA cycle activity as well as cardiac growth and contractility in the heart ventricle. Increased cardiac efficiency may offer significant benefits in the demanding Aquaculture situations. PMID:22577878

  12. Effects of acid rain on mycorrhizal infection and N cycling in forest soils

    SciTech Connect

    Stroo, H.F.

    1986-01-01

    Increasing the acidity of simulated rain from pH 5.6 to 3.0 reduced the number of mycorrhizal roots on white pine seedlings by 20% after 16 weeks of exposure. Mycorrhizal infection of red oaks was 25% less at a rain pH of 3.5 than at pH 5.6. Simulated acid rain also caused increases in the N contents, net photosynthesis, and growth of seedlings, as well as decreases in root:shoot ratios and in the concentration of sucrose in the roots. To measure the effects of acid rain on N mineralization, nitrification, and total inorganic N, columns containing samples from the surface horizons of 12 forest soils were exposed to simulated rain at 3 times ambient deposition rates for 16 weeks. The effects on N mineralization varied between soils, with the greatest inhibitions being observed in soils with low organic matter contents. The apparent protection by organic matter was associated with an increase in short-term buffering capacity. The average amount of N mineralized after exposure was not significantly affected by rain pH. Similarly, nitrification was inhibited during exposure to simulated rain at pH 3.5, but was unaffected after exposure. Enrichments from an acid forest soil failed to show the presence of autotrophic nitrifiers, and the effects of temperature and selective inhibitors indicated that fungi were primarily responsible for nitrification in this soil. A fungus capable of heterotrophic nitrification at pH 4.0 was isolated and identified as Absidia cylindrospora Hagem.

  13. Lactic Acid Bacteria in Durum Wheat Flour Are Endophytic Components of the Plant during Its Entire Life Cycle

    PubMed Central

    Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; De Angelis, Maria

    2015-01-01

    This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors. PMID:26187970

  14. Lactic Acid Bacteria in Durum Wheat Flour Are Endophytic Components of the Plant during Its Entire Life Cycle.

    PubMed

    Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; Gobbetti, Marco; De Angelis, Maria

    2015-10-01

    This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors. PMID:26187970

  15. Parametric Flutter Analysis of the TCA Configuration and Recommendation for FFM Design and Scaling

    NASA Technical Reports Server (NTRS)

    Baker, Myles; Lenkey, Peter

    1997-01-01

    The current HSR Aeroelasticity plan to design, build, and test a full span, free flying transonic flutter model in the TDT has many technical obstacles that must be overcome for a successful program. One technical obstacle is the determination of a suitable configuration and point in the sky to use in setting the scaling point for the ASE models program. Determining this configuration and point in the sky requires balancing several conflicting requirements, including model buildability, tunnel test safety, and the ability of the model to represent the flutter mechanisms of interest. As will be discussed in detail in subsequent sections, the current TCA design exhibits several flutter mechanisms of interest. It has been decided that the ASE models program will focus on the low frequency symmetric flutter mechanism, and will make no attempt to investigate high frequency flutter mechanisms. There are several reasons for this choice. First, it is believed that the high frequency flutter mechanisms are similar in nature to classical wing bending/torsion flutter, and therefore there is more confidence that this mechanism can be predicted using current techniques. The low frequency mode, on the other hand, is a highly coupled mechanism involving wing, body, tail, and engine motion which may be very difficult to predict. Second, the high frequency flutter modes result in very small weight penalties (several hundred pounds), while suppression of the low frequency mechanism inside the flight envelope causes thousands of pounds to be added to the structure. In order to successfully test the low frequency flutter mode of interest, a suitable starting configuration and point in the sky must be identified. The configuration and point in the sky must result in a wind tunnel model that (1) represents the low-frequency wing/body/engine/empennage flutter mechanisms that are unique to HSCT configurations, (2) flutters at an acceptably low frequency in the tunnel, (3) flutters at an

  16. Self-nanoemulsifying drug delivery system of trans-cinnamic acid: formulation development and pharmacodynamic evaluation in alloxan-induced type 2 diabetic rat model.

    PubMed

    Wang, Houyong; Li, Qiang; Deng, Wenwen; Omari-Siaw, E; Wang, Qilong; Wang, Shicheng; Wang, Shengli; Cao, Xia; Xu, Ximing; Yu, Jiangnan

    2015-03-01

    The objective of this study was to formulate a self-nanoemulsifying oral drug delivery system (SNEDDS) for the poorly water-soluble trans-Cinnamic acid (t-CA SNEDDS) that could be evaluated for its antihyperglycemic efficacy in comparison to the parent t-CA in an alloxan-induced diabetic rat model. A SNEDDS formulation consisting of 60% surfactant (Kolliphor EL), 10% co-surfactant (PEG 400) and 30% oil (isopropyl myristate) proved to be optimal. t-CA SNEDDS (80 mg/kg, p.o.), t-CA suspension (80 mg/kg, p.o.), and Metformin Hydrochloride Tablets (230 mg/kg, p.o.) were administer qdfor 30 days to diabetic rats. After treatment the body weight of diabetic rats was increased, blood glucose levels, total cholesterol, and triglyceride in the serum tended to be normalized, while the levels of alanine aminotransferase and aspartate aminotransferase were markedly decreased. The effects of t-CA SNEDDS were superior to that of the t-CA suspension. The present study demonstrated that t-CA was effective in attenuating the effects of alloxan treatment and that t-CA SNEDDS with a more favorable absorption and enhanced bioavailability is more effective than t-CA. PMID:25847843

  17. [Effect of tricarboxylic acid cycle intermediates on nitric oxide system during acute hypoxia].

    PubMed

    Kurhaliuk, N M

    2002-01-01

    Effects Crebs Cycle of exogenous intermediates sodium succinate (50 mg/kg) and sodium alpha-ketoglutarate (200 mg/kg) on processes of mitochondrial ADP-stimulated respiration (using as substrates of oxidation 0.35 mM succinate, 1 mM alpha-ketoglutarate), production of nitric oxide under NO2-, NO3-, as well as carbamide, putrescyne content and processes of lipid peroxidation in the rats liver under acute hypoxia (7% O2 in N2, 30 min) have been studied. It was shown, that the exogenous sodium alpha-ketoglutarate increases nitric oxide content, aminotransferase activation, inhibition of succinatedehydrogenase simultaneously more than exogenous sodium succinate. It correlates with decreasing of processes lipid peroxidation in liver. PMID:14964867

  18. Substitution of amino acids in helix F of bacteriorhodopsin: Effects on the photochemical cycle

    SciTech Connect

    Ahl, P.L.; Stern, L.J.; Mogi, T.; Khorana, H.G.; Rothschild, K.J. )

    1989-12-26

    The effects of amino acid substitutions in helix F of bacteriorhodopsin on the photocycle of this light-driven proton pump were studied. The photocycles of Ser-183----Ala and Glu-194----Gln mutants were qualitatively similar to that of wild-type bacteriorhodopsin produced in Escherichia coli and bacteriorhodopsin from Halobacterium halobium. The substitution of a Phe for either Trp-182 or Trp-189 significantly reduced the fraction of photocycling bacteriorhodopsin. The amino acid substitutions Tyr-185----Phe and Ser-193----Ala substantially increased the lifetime of the photocycle without substantially increasing the lifetime of the M photocycle intermediate. Similar results were also obtained with the Pro-186----Gly substitution. In contrast, replacing Pro-186 with the larger residue Leu inhibited the formation of the M photocycle intermediate. These results are consistent with a structural model of the retinal-binding pocket suggested by low-temperature UV/visible and Fourier transform infrared difference spectroscopies that has Trp-182, Tyr-185, Pro-186, and Trp-189 forming part of the binding pocket.

  19. Role of Acid Metabolism in Streptomyces coelicolor Morphological Differentiation and Antibiotic Biosynthesis

    PubMed Central

    Viollier, Patrick H.; Minas, Wolfgang; Dale, Glenn E.; Folcher, Marc; Thompson, Charles J.

    2001-01-01

    Studies of citrate synthase (CitA) were carried out to investigate its role in morphological development and biosynthesis of antibiotics in Streptomyces coelicolor. Purification of CitA, the major vegetative enzyme activity, allowed characterization of its kinetic properties. The apparent Km values of CitA for acetyl coenzyme A (acetyl-CoA) (32 μM) and oxaloacetate (17 μM) were similar to those of citrate synthases from other gram-positive bacteria and eukaryotes. CitA was not strongly inhibited by various allosteric feedback inhibitors (NAD+, NADH, ATP, ADP, isocitrate, or α-ketoglutarate). The corresponding gene (citA) was cloned and sequenced, allowing construction of a citA mutant (BZ2). BZ2 was a glutamate auxotroph, indicating that citA encoded the major citrate synthase allowing flow of acetyl-CoA into the tricarboxylic acid (TCA) cycle. Interruption of aerobic TCA cycle-based metabolism resulted in acidification of the medium and defects in morphological differentiation and antibiotic biosynthesis. These developmental defects of the citA mutant were in part due to a glucose-dependent medium acidification that was also exhibited by some other bald mutants. Unlike other acidogenic bald strains, citA and bldJ mutants were able to produce aerial mycelia and pigments when the medium was buffered sufficiently to maintain neutrality. Extracellular complementation studies suggested that citA defines a new stage of the Streptomyces developmental cascade. PMID:11325948

  20. Anticancer and apoptotic activities of oleanolic acid are mediated through cell cycle arrest and disruption of mitochondrial membrane potential in HepG2 human hepatocellular carcinoma cells.

    PubMed

    Zhu, Yue-Yong; Huang, Hong-Yan; Wu, Yin-Lian

    2015-10-01

    Hepatocellular carcinoma (HCC) is an aggressive form of cancer, with high rates of morbidity and mortality, a poor prognosis and limited therapeutic options. The objective of the present study was to demonstrate the anticancer activity of oleanolic acid in HepG2 human HCC cells. Cell viability was evaluated using an MTT assay, following administration of various doses of oleanolic acid. The effect of oleanolic acid on cell cycle phase distribution and mitochondrial membrane potential was evaluated using flow cytometry with propidium iodide and rhodamine‑123 DNA‑binding cationic fluorescent dyes. Fluorescence microscopy was employed to detect morphological changes in HepG2 cells following oleanolic acid treatment. The results revealed that oleanolic acid induced a dose‑dependent, as well as time‑dependent inhibition in the growth of HepG2 cancer cells. Following acridine orange and ethidium bromide staining, treatment with various doses (0, 5, 25 and 50 µM) of oleanolic acid induced typical morphological changes associated with apoptosis, including cell shrinkage, membrane blebbing, nuclear condensation and apoptotic body formation. Cell cycle analysis revealed that oleanolic acid induced cell cycle arrest in HepG2 cells at the sub‑G1 (apoptotic) phase of the cell cycle, in a dose‑dependent manner. Staining with Annexin V‑fluorescein isothiocyanate and propidium iodide revealed that apoptosis occurred early in these cells. Oleanolic acid treatment also resulted in fragmentation of nuclear DNA in a dose‑dependent manner, producing the typical features of DNA laddering on an agarose gel. The results also demonstrated that oleanolic acid treatment resulted in a potent loss of mitochondrial membrane potential, which also occurred in a dose‑dependent manner. Therefore, oleanolic acid may be used as a therapeutic agent in the treatment of human HCC. PMID:26151733

  1. Perillyl alcohol and perillic acid induced cell cycle arrest and apoptosis in non small cell lung cancer cells.

    PubMed

    Yeruva, Laxmi; Pierre, Keon J; Elegbede, Abiodun; Wang, Robert C; Carper, Stephen W

    2007-11-18

    Plant products such as perillyl alcohol have been reported to possess anti-tumor activities against a number of human cancers though the mechanism of action has not yet been elucidated. The effects of perillyl alcohol (POH) and its metabolite perillic acid (PA) on the proliferation of non small cell lung cancer (NSCLC, A549, and H520) cells were investigated. Both POH and PA elicited dose-dependent cytotoxicity, induced cell cycle arrest and apoptosis with increasing expression of bax, p21 and caspase-3 activity in both the cell lines. Combination studies revealed that exposing the cells to an IC50 concentration of POH or PA sensitized the cells to cisplatin and radiation in a dose-dependent manner. These results indicate that POH and PA in combination therapy may have chemotherapeutic value against NSCLC. PMID:17888568

  2. Pathways of acid mine drainage to Clear Lake: implications for mercury cycling.

    PubMed

    Shipp, William G; Zierenberg, Robert A

    2008-12-01

    Pore fluids from Clear Lake sediments collected near the abandoned Sulphur Bank Mercury Mine have low pH (locally <4) and elevated sulfate (> or =197 mmol/L), aluminum (> or =52 mmol/L), and iron (> or =28 mmol/L) contents derived from oxidation of sulfide minerals at the mine site. Acid mine drainage (AMD) is entering Clear Lake by advective subsurface flow nearest the mine and by diffusion at greater distances. Oxygen and hydrogen isotope ratios, combined with pore fluid compositions, constrain the sources and pathways of contaminated fluids. Sediment cores taken nearest the mine have the highest concentrations of dissolved sulfate, aluminum, and iron, which are contributed by direct subsurface flow of AMD from sulfide-bearing waste rock. Sediment cores as far as 100 m west of the Clear Lake shoreline show the presence of AMD that originated in the acidic lake that occupies the abandoned Herman Pit at the mine site. High sulfate content in the AMD has the potential to promote the activity of sulfate-reducing bacteria in the organic-rich lake sediments, which leads to methylation of Hg+2, making it both more toxic and bioavailable. Quantitative depletion of pore water sulfate at depth and sulfur isotope values of diagenetic pyrite near 0 per thousand indicate that sulfate availability limits the extent of sulfate reduction in the lake sediments away from the mine. Profiles of pore water sulfate in the sediments near the mine show that excess sulfate is available to support the activity of sulfate-reducing bacteria near the mine site. Enriched isotope values of dissolved sulfate (as high as 17.1 per thousand) and highly depleted isotope values for diagenetic pyrite (as low as -22.6 per thousand) indicate active bacterial sulfate reduction in the AMD-contaminated sediments. Sulfate- and iron-rich acid mine drainage entering Clear Lake by shallow subsurface flow likely needs to be controlled in order to lower the environmental impacts of Hg in the Clear Lake

  3. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand

    PubMed Central

    Hug, Katrin; Maher, William A.; Stott, Matthew B.; Krikowa, Frank; Foster, Simon; Moreau, John W.

    2014-01-01

    Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55–75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18–25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

  4. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.

    PubMed

    Hug, Katrin; Maher, William A; Stott, Matthew B; Krikowa, Frank; Foster, Simon; Moreau, John W

    2014-01-01

    Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

  5. IDH1 Mutations Alter Citric Acid Cycle Metabolism and Increase Dependence on Oxidative Mitochondrial Metabolism

    PubMed Central

    Grassian, Alexandra R.; Parker, Seth J.; Davidson, Shawn M.; Divakarun, Ajit S.; Green, Courtney R.; Zhang, Xiamei; Slocum, Kelly L.; Pu, Minying; Lin, Fallon; Vickers, Chad; Joud-Caldwell, Carol; Chung, Franklin; Yin, Hong; Handly, Erika D.; Straub, Christopher; Growney, Joseph D.; Vander Heiden, Matthew G.; Murphy, Anne N.; Pagliarini, Raymond; Metallo, Christian M.

    2016-01-01

    Oncogenic mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) occur in several types of cancer, but the metabolic consequences of these genetic changes are not fully understood. In this study, we performed 13C metabolic flux analysis on a panel of isogenic cell lines containing heterozygous IDH1/2 mutations. We observed that under hypoxic conditions, IDH1-mutant cells exhibited increased oxidative tricarboxylic acid metabolism along with decreased reductive glutamine metabolism, but not IDH2-mutant cells. However, selective inhibition of mutant IDH1 enzyme function could not reverse the defect in reductive carboxylation activity. Furthermore, this metabolic reprogramming increased the sensitivity of IDH1-mutant cells to hypoxia or electron transport chain inhibition in vitro. Lastly, IDH1-mutant cells also grew poorly as subcutaneous xenografts within a hypoxic in vivo microenvironment. Together, our results suggest therapeutic opportunities to exploit the metabolic vulnerabilities specific to IDH1 mutation. PMID:24755473

  6. Nitrogen cycling in s subarctic Alaskan watershed: the role of lichens and the potential effects of acid deposition

    SciTech Connect

    Gunther, A.J.

    1987-01-01

    It has been hypothesized that the loss of nitrogen-fixing lichens due to stress from air pollution could have adverse effects upon nitrogen availability, and thus primary productivity, in some ecosystems. There is general agreement, however, that the ecological role of these lichens has not been sufficiently well defined to determine whether they are keystone species. The objectives of this study were: (1) to examine the importance of nitrogen-fixing lichens to the nitrogen cycle in the drainage of Brooks Lake, Alaska, a nitrogen-limited nursery lake for the commercially important sockeye salmon (Oncorhychus nerka); and (2) to investigate the sensitivity of nitrogen fixation by lichens in this ecosystem to acid deposition. Biological nitrogen fixation was found to be the major source of new nitrogen to the Brooks Lake drainage. The rate of fixation is approximately 3 kg N/ha-yr, which compares to 0.3 kg N/ha-yr in precipitation and only 0.02 kg N/ha-yr in returning adult salmon. Cyanophillic lichens contribute about 0.21 kg N/ha-yr. The low levels of nitrogen in precipitation, combined with a lack of nitrogen-fixation activity in open lake waters, indicates that nitrogen in tributary streams is the major source of new nitrogen for Brooks Lake. The measurements of nitrogen inputs, along with estimates of other stocks and flows of nitrogen, were used to construct a steady-state box model of the nitrogen cycle in the drainage.

  7. Determination of sup 13 C labeling pattern of citric acid cycle intermediates by gas chromatography-mass spectrometry

    SciTech Connect

    Di Donato, L.; Montgomery, J.A.; Des Rosiers, C.; David, F.; Garneau, M.; Brunengraber, H. )

    1990-02-26

    Investigations of the regulation of the citric acid cycle require determination of labeling patterns of cycle intermediates. These were assayed to date, using infusion of: (i) ({sup 14}C)tracer followed by chemical degradation of intermediates and (ii) ({sup 13}C)tracer followed by NMR analysis of intermediates. The authors developed a strategy to analyze by GC-MS the ({sup 13}C) labeling pattern of {mu}mole samples of citrate (CIT), isocitrate (ICIT), 2-ketoglutarate (2-KG), glutamate (GLU) and glutamine (GLN). These are enzymatically or chemically converted to 2-KG, ICIT, 4-aminobutyrate (GABA) and 2-hydroxyglutarate (2-OHG). GC-MS analyses of TMS or TBDMS derivatives of these compounds yield the enrichment of each carbon. The authors confirmed the identity of each fragment using the spectra of (1-{sup 13}C), (5-{sup 13}C), (2,3,3,4,4-{sup 2}H{sub 5})glutamate and (1-{sup 13}C), (1,4-{sup 13}C)GABA.

  8. Prolactin messenger ribonucleic acid levels, prolactin synthesis, and radioimmunoassayable prolactin during the estrous cycle in the Golden Syrian hamster

    SciTech Connect

    Massa, J.S. ); Blask, D.E. )

    1990-01-01

    The purpose of this study was to observe the molecular dynamics of pituitary prolactin (PRL) gene expression during the estrous cycle of the Golden Syrian hamster. PRL messenger ribonucleic acid (mRNA) levels, PRL synthesis were measured in the morning on each day of the cycle. We observed that all of these PRL indices declined or did not change from Day 2 to Day 3 of the cycle. From Day 3 to Day 4 however, PRL mRNA levels increased 33-38% and media {sup 3}H-PRL increased 32-42%, while there were no significant changes in pituitary {sup 3}H-PRL, or RIA-PRL in the media or pituitary. From Day 4 to Day 1 (estrus) there was reciprocal change in the levels of {sup 3}H-PRL in the pituitary vs. the media, with the former increasing 37-50% and the latter decreasing 25-32%. Pituitary RIA-PRL did also increased 45-64% from Day 4 to Day 1 while media RIA-PRL did not change. These data are consistent with the following hypothesis: On the morning of proestrus(Day 4) in the hamster, PRL mRNA levels are elevated compared to those on Day 3, signaling an increase in PRL synthesis. This newly synthesized PRL is shunted into a readily releasable pool on the morning of Day 4 (contributing to the afternoon surge of serum PRL), and into a preferentially stored pool by the morning of Day 1.

  9. Analysis of lead/acid battery life cycle factors: their impact on society and the lead industry

    NASA Astrophysics Data System (ADS)

    Robertson, J. G. S.; Wood, J. R.; Ralph, B.; Fenn, R.

    The underlying theme of this paper is that society, globally, is undergoing a fundamental conceptual shift in the way it views the environment and the role of industry within it. There are views in certain quarters that this could result in the virtual elimination of the lead industry's entire product range. Despite these threats, it is argued that the prospects for the lead industry appear to be relatively favourable in a number of respects. The industry's future depends to a significant degree, however, upon its ability to argue its case in a number of key areas. It is contended, therefore, that if appropriate strategies and means are promulgated, the prospects of the industry would appear to be relatively healthy. But, for this to happen with optimal effectiveness, a conceptual change will be necessary within the industry. New strategies and tools will have to be developed. These will require a significantly more integrated, holistically based and 'reflexive' approach than previously. The main elements of such an approach are outlined. With reference to the authors' ongoing research into automotive lead/acid starting lighting ignition (SLI) batteries, the paper shows how the technique of in-depth life cycle assessment (LCA), appropriately adapted to the needs of the industry, will provide a crucial role in this new approach. It also shows how it may be used as an internal design and assessment tool to identify those stages in the battery life cycle that give rise to the greatest environmental burdens, and to assess the effects of changes in the cycle to those burdens. It is argued that the development of this approach requires the serious and urgent attention of the whole of the lead industry. Also to make the LCA tool fully effective, it must be based on a 'live' database that is produced, maintained and continually updated by the industry.

  10. Ecotypic variability in the metabolic response of seeds to diurnal hydration-dehydration cycles and its relationship to seed vigor.

    PubMed

    Bai, Bing; Sikron, Noga; Gendler, Tanya; Kazachkova, Yana; Barak, Simon; Grafi, Gideon; Khozin-Goldberg, Inna; Fait, Aaron

    2012-01-01

    Seeds in the seed bank experience diurnal cycles of imbibition followed by complete dehydration. These conditions pose a challenge to the regulation of germination. The effect of recurring hydration-dehydration (Hy-Dh) cycles were tested on seeds from four Arabidopsis thaliana accessions [Col-0, Cvi, C24 and Ler]. Diurnal Hy-Dh cycles had a detrimental effect on the germination rate and on the final percentage of germination in Col-0, Cvi and C24 ecotypes, but not in the Ler ecotype, which showed improved vigor following the treatments. Membrane permeability measured by ion conductivity was generally increased following each Hy-Dh cycle and was correlated with changes in the redox status represented by the GSSG/GSH (oxidized/reduced glutathione) ratio. Among the ecotypes, Col-0 seeds displayed the highest membrane permeability, whilst Ler was characterized by the greatest increase in electrical conductivity following Hy-Dh cycles. Following Dh 2 and Dh 3, the respiratory activity of Ler seeds significantly increased, in contrast to the other ecotypes, indicative of a dramatic shift in metabolism. These differences were associated with accession-specific content and patterns of change of (i) cell wall-related laminaribiose and mannose; (ii) fatty acid composition, specifically of the unsaturated oleic acid and α-linoleic acid; and (iii) asparagine, ornithine and the related polyamine putrescine. Furthermore, in the Ler ecotype the content of the tricarboxylic acid (TCA) cycle intermediates fumarate, succinate and malate increased in response to dehydration, in contrast to a decrease in the other three ecotypes. These findings provide a link between seed respiration, energy metabolism, fatty acid β-oxidation, nitrogen mobilization and membrane permeability and the improved germination of Ler seeds following Hy-Dh cycles. PMID:22156384

  11. Metabolic modeling of fumaric acid production by Rhizopus arrhizus

    SciTech Connect

    Gangl, I.C.; Weigand, W.W.; Keller, F.A.

    1991-12-31

    A metabolic model is developed for fumaric acid production by Rhizopus arrhizus. The model describes the reaction network and the extents of reaction in terms of the concentrations of the measurable species. The proposed pathway consists of the Embden-Meyerhof pathway and two pathways to FA production, both of which require CO{sub 2} fixation (the forward and the reverse TCA cycles). Relationships among the measurable quantities, in addition to those obtainable by a macroscopic mass balance, are found by invoking a pseudo-steady-state assumption on the nonaccumulating species in the pathway. Applications of the metabolic model, such as verifying the proposed pathway, obtaining the theoretical yield and selectivity, and detecting experimental errors, are discussed.

  12. Fungi contribute critical but spatially varying roles in nitrogen and carbon cycling in acid mine drainage

    DOE PAGESBeta

    Mosier, Annika C.; Miller, Christopher S.; Frischkorn, Kyle R.; Ohm, Robin A.; Li, Zhou; LaButti, Kurt; Lapidus, Alla; Lipzen, Anna; Chen, Cindy; Johnson, Jenifer; et al

    2016-03-03

    The ecosystem roles of fungi have been extensively studied by targeting one organism and/or biological process at a time, but the full metabolic potential of fungi has rarely been captured in an environmental context. We hypothesized that fungal genome sequences could be assembled directly from the environment using metagenomics and that transcriptomics and proteomics could simultaneously reveal metabolic differentiation across habitats. We reconstructed the near-complete 27 Mbp genome of a filamentous fungus, Acidomyces richmondensis, and evaluated transcript and protein expression in floating and streamer biofilms from an acid mine drainage (AMD) system. A. richmondensis transcripts involved in denitrification and inmore » the degradation of complex carbon sources (including cellulose) were up-regulated in floating biofilms, whereas central carbon metabolism and stress-related transcripts were significantly up-regulated in streamer biofilms. Finally, these findings suggest that the biofilm niches are distinguished by distinct carbon and nitrogen resource utilization, oxygen availability, and environmental challenges. An isolated A. richmondensis strain from this environment was used to validate the metagenomics-derived genome and confirm nitrous oxide production at pH 1. Overall, our analyses defined mechanisms of fungal adaptation and identified a functional shift related to different roles in carbon and nitrogen turnover for the same species of fungi growing in closely located but distinct biofilm niches.« less

  13. Fungi Contribute Critical but Spatially Varying Roles in Nitrogen and Carbon Cycling in Acid Mine Drainage

    PubMed Central

    Mosier, Annika C.; Miller, Christopher S.; Frischkorn, Kyle R.; Ohm, Robin A.; Li, Zhou; LaButti, Kurt; Lapidus, Alla; Lipzen, Anna; Chen, Cindy; Johnson, Jenifer; Lindquist, Erika A.; Pan, Chongle; Hettich, Robert L.; Grigoriev, Igor V.; Singer, Steven W.; Banfield, Jillian F.

    2016-01-01

    The ecosystem roles of fungi have been extensively studied by targeting one organism and/or biological process at a time, but the full metabolic potential of fungi has rarely been captured in an environmental context. We hypothesized that fungal genome sequences could be assembled directly from the environment using metagenomics and that transcriptomics and proteomics could simultaneously reveal metabolic differentiation across habitats. We reconstructed the near-complete 27 Mbp genome of a filamentous fungus, Acidomyces richmondensis, and evaluated transcript and protein expression in floating and streamer biofilms from an acid mine drainage (AMD) system. A. richmondensis transcripts involved in denitrification and in the degradation of complex carbon sources (including cellulose) were up-regulated in floating biofilms, whereas central carbon metabolism and stress-related transcripts were significantly up-regulated in streamer biofilms. These findings suggest that the biofilm niches are distinguished by distinct carbon and nitrogen resource utilization, oxygen availability, and environmental challenges. An isolated A. richmondensis strain from this environment was used to validate the metagenomics-derived genome and confirm nitrous oxide production at pH 1. Overall, our analyses defined mechanisms of fungal adaptation and identified a functional shift related to different roles in carbon and nitrogen turnover for the same species of fungi growing in closely located but distinct biofilm niches. PMID:26973616

  14. Fungi Contribute Critical but Spatially Varying Roles in Nitrogen and Carbon Cycling in Acid Mine Drainage.

    PubMed

    Mosier, Annika C; Miller, Christopher S; Frischkorn, Kyle R; Ohm, Robin A; Li, Zhou; LaButti, Kurt; Lapidus, Alla; Lipzen, Anna; Chen, Cindy; Johnson, Jenifer; Lindquist, Erika A; Pan, Chongle; Hettich, Robert L; Grigoriev, Igor V; Singer, Steven W; Banfield, Jillian F

    2016-01-01

    The ecosystem roles of fungi have been extensively studied by targeting one organism and/or biological process at a time, but the full metabolic potential of fungi has rarely been captured in an environmental context. We hypothesized that fungal genome sequences could be assembled directly from the environment using metagenomics and that transcriptomics and proteomics could simultaneously reveal metabolic differentiation across habitats. We reconstructed the near-complete 27 Mbp genome of a filamentous fungus, Acidomyces richmondensis, and evaluated transcript and protein expression in floating and streamer biofilms from an acid mine drainage (AMD) system. A. richmondensis transcripts involved in denitrification and in the degradation of complex carbon sources (including cellulose) were up-regulated in floating biofilms, whereas central carbon metabolism and stress-related transcripts were significantly up-regulated in streamer biofilms. These findings suggest that the biofilm niches are distinguished by distinct carbon and nitrogen resource utilization, oxygen availability, and environmental challenges. An isolated A. richmondensis strain from this environment was used to validate the metagenomics-derived genome and confirm nitrous oxide production at pH 1. Overall, our analyses defined mechanisms of fungal adaptation and identified a functional shift related to different roles in carbon and nitrogen turnover for the same species of fungi growing in closely located but distinct biofilm niches. PMID:26973616

  15. Subcellular location and photodynamic therapeutic effect of chlorin e6 in the human tongue squamous cell cancer Tca8113 cell line

    PubMed Central

    LUO, WEI; LIU, RONG-SEN; ZHU, JIAN-GUO; LI, YING-CHAO; LIU, HONG-CHEN

    2015-01-01

    The present study aimed to investigate the distribution and photodynamic therapeutic effect of chlorin e6 (Ce6) in the human tongue squamous cell carcinoma Tca8113 cell line in vitro. The distribution of Ce6 in the Tca8113 cells was observed in situ combined with mitochondrial and lysosomal fluorescent probes. Next, 630-nm semiconductor laser irradiation was performed. The MTS colorimetric method was used to determine cell survival. Annexin V fluorescein isothiocyanate/propidium iodide (PI) double staining was used to detect early apoptosis following photodynamic therapy (PDT). The flow cytometer was used to analyze the DNA content subsequent to PI-staining. It was observed that Ce6 could combine with the cellular membrane following 30 min of incubation with the Tca8113 cells. As the length of incubation increased, Ce6 gradually entered the cells in a particular distribution and reached saturation by 3 h. Co-localization analysis demonstrated that Ce6 was more likely to be present in the mitochondria than in the lysosomes. The cells incubated with 5 μg/ml Ce6 for 24 h exhibited a low toxicity of 5%, however, following light irradiation, Ce6-PDT was able to kill the Tca8113 cells in vitro. The cell toxicity was positively correlated with Ce6 concentration and light dose, therefore, the effect of Ce6 was concentration/dose-dependent (P<0.01). The lower Ce6 concentrations and light doses could significantly induce apoptosis in the Tca8113 cells, while higher doses increased necrosis/percentage of dead cells. In summary, Ce6 saturated the Tca8113 cells following 3 h of incubation. Furthermore, Ce6-PDT effectively killed the cultured Tca8113 cells in vitro at a safe concentration. At a low concentration and light dose, Ce6 is more likely to induce cell apoptosis via the mitochondria than the lysosomes. PMID:25621023

  16. An Impaired Respiratory Electron Chain Triggers Down-regulation of the Energy Metabolism and De-ubiquitination of Solute Carrier Amino Acid Transporters.

    PubMed

    Aretz, Ina; Hardt, Christopher; Wittig, Ilka; Meierhofer, David

    2016-05-01

    Hundreds of genes have been associated with respiratory chain disease (RCD), the most common inborn error of metabolism so far. Elimination of the respiratory electron chain by depleting the entire mitochondrial DNA (mtDNA, ρ(0) cells) has therefore one of the most severe impacts on the energy metabolism in eukaryotic cells. In this study, proteomic data sets including the post-translational modifications (PTMs) phosphorylation and ubiquitination were integrated with metabolomic data sets and selected enzyme activities in the osteosarcoma cell line 143B.TK(-) A shotgun based SILAC LC-MS proteomics and a targeted metabolomics approach was applied to elucidate the consequences of the ρ(0) state. Pathway and protein-protein interaction (PPI) network analyses revealed a nonuniform down-regulation of the respiratory electron chain, the tricarboxylic acid (TCA) cycle, and the pyruvate metabolism in ρ(0) cells. Metabolites of the TCA cycle were dysregulated, such as a reduction of citric acid and cis-aconitic acid (six and 2.5-fold), and an increase of lactic acid, oxalacetic acid (both twofold), and succinic acid (fivefold) in ρ(0) cells. Signaling pathways such as GPCR, EGFR, G12/13 alpha, and Rho GTPases were up-regulated in ρ(0) cells, which could be indicative for the mitochondrial retrograde response, a pathway of communication from mitochondria to the nucleus. This was supported by our phosphoproteome data, which revealed two main processes, GTPase-related signal transduction and cytoskeleton organization. Furthermore, a general de-ubiquitination in ρ(0) cells was observed, for example, 80S ribosomal proteins were in average threefold and SLC amino acid transporters fivefold de-ubiquitinated. The latter might cause the observed significant increase of amino acid levels in ρ(0) cells. We conclude that an elimination of the respiratory electron chain, e.g. mtDNA depletion, not only leads to an uneven down-regulation of mitochondrial energy pathways, but also

  17. De novo Fatty Acid Biosynthesis Contributes Significantly to Establishment of a Bioenergetically Favorable Environment for Vaccinia Virus Infection

    PubMed Central

    Greseth, Matthew D.; Traktman, Paula

    2014-01-01

    The poxvirus life cycle, although physically autonomous from the host nucleus, is nevertheless dependent upon cellular functions. A requirement for de novo fatty acid biosynthesis was implied by our previous demonstration that cerulenin, a fatty acid synthase inhibitor, impaired vaccinia virus production. Here we show that additional inhibitors of this pathway, TOFA and C75, reduce viral yield significantly, with partial rescue provided by exogenous palmitate, the pathway's end-product. Palmitate's major role during infection is not for phospholipid synthesis or protein palmitoylation. Instead, the mitochondrial import and β-oxidation of palmitate are essential, as shown by the impact of etomoxir and trimetazidine, which target these two processes respectively. Moreover, the impact of these inhibitors is exacerbated in the absence of exogenous glucose, which is otherwise dispensable for infection. In contrast to glucose, glutamine is essential for productive viral infection, providing intermediates that sustain the TCA cycle (anaplerosis). Cumulatively, these data suggest that productive infection requires the mitochondrial β-oxidation of palmitate which drives the TCA cycle and energy production. Additionally, infection causes a significant rise in the cellular oxygen consumption rate (ATP synthesis) that is ablated by etomoxir. The biochemical progression of the vaccinia life cycle is not impaired in the presence of TOFA, C75, or etomoxir, although the levels of viral DNA and proteins synthesized are somewhat diminished. However, by reversibly arresting infections at the onset of morphogenesis, and then monitoring virus production after release of the block, we determined that virion assembly is highly sensitive to TOFA and C75. Electron microscopic analysis of cells released into C75 revealed fragmented aggregates of viroplasm which failed to be enclosed by developing virion membranes. Taken together, these data indicate that vaccinia infection, and in

  18. De novo fatty acid biosynthesis contributes significantly to establishment of a bioenergetically favorable environment for vaccinia virus infection.

    PubMed

    Greseth, Matthew D; Traktman, Paula

    2014-03-01

    The poxvirus life cycle, although physically autonomous from the host nucleus, is nevertheless dependent upon cellular functions. A requirement for de novo fatty acid biosynthesis was implied by our previous demonstration that cerulenin, a fatty acid synthase inhibitor, impaired vaccinia virus production. Here we show that additional inhibitors of this pathway, TOFA and C75, reduce viral yield significantly, with partial rescue provided by exogenous palmitate, the pathway's end-product. Palmitate's major role during infection is not for phospholipid synthesis or protein palmitoylation. Instead, the mitochondrial import and β-oxidation of palmitate are essential, as shown by the impact of etomoxir and trimetazidine, which target these two processes respectively. Moreover, the impact of these inhibitors is exacerbated in the absence of exogenous glucose, which is otherwise dispensable for infection. In contrast to glucose, glutamine is essential for productive viral infection, providing intermediates that sustain the TCA cycle (anaplerosis). Cumulatively, these data suggest that productive infection requires the mitochondrial β-oxidation of palmitate which drives the TCA cycle and energy production. Additionally, infection causes a significant rise in the cellular oxygen consumption rate (ATP synthesis) that is ablated by etomoxir. The biochemical progression of the vaccinia life cycle is not impaired in the presence of TOFA, C75, or etomoxir, although the levels of viral DNA and proteins synthesized are somewhat diminished. However, by reversibly arresting infections at the onset of morphogenesis, and then monitoring virus production after release of the block, we determined that virion assembly is highly sensitive to TOFA and C75. Electron microscopic analysis of cells released into C75 revealed fragmented aggregates of viroplasm which failed to be enclosed by developing virion membranes. Taken together, these data indicate that vaccinia infection, and in

  19. Toxicity of haloacetic acids to freshwater algae.

    PubMed

    Roberts, Jayne F; van Egmond, Roger; Price, Oliver R

    2010-01-01

    Haloacetic acids (HAA), such as trichloroacetic acid (TCA), are commonly occurring by-products from disinfection and bleaching processes using sodium hypochlorite. Currently, the lowest no observed effect concentration (NOEC) for TCA is reported to be 8.7microgL(-1), which was derived from a toxicity study conducted in 1981 on Chlorella pyrenoidosa. The purity of the test material was not documented and it is unknown if other halogenated impurities or co-formulants were present. However, this NOEC is used to derive a predicted no effect concentration, which is used in various regulatory risk assessments. We present a range of algal toxicity studies conducted on five different algal species and two HAAs and observed no toxicity of TCA to C. pyrenoidosa at 115mgL(-1). The most sensitive species to TCA (NOEC, 3mgL(-1)) were Pseudokirchneriella subcapitata and Scenedesmus subspicatus, demonstrating that the toxicity of TCA to algae is over two orders of magnitude less sensitive than previously reported. PMID:19828197

  20. Long-Chain Fatty Acid Combustion Rate Is Associated with Unique Metabolite Profiles in Skeletal Muscle Mitochondria

    PubMed Central

    Seifert, Erin L.; Fiehn, Oliver; Bezaire, Véronic; Bickel, David R.; Wohlgemuth, Gert; Adams, Sean H.; Harper, Mary-Ellen

    2010-01-01

    Background/Aim Incomplete or limited long-chain fatty acid (LCFA) combustion in skeletal muscle has been associated with insulin resistance. Signals that are responsive to shifts in LCFA β-oxidation rate or degree of intramitochondrial catabolism are hypothesized to regulate second messenger systems downstream of the insulin receptor. Recent evidence supports a causal link between mitochondrial LCFA combustion in skeletal muscle and insulin resistance. We have used unbiased metabolite profiling of mouse muscle mitochondria with the aim of identifying candidate metabolites within or effluxed from mitochondria and that are shifted with LCFA combustion rate. Methodology/Principal Findings Large-scale unbiased metabolomics analysis was performed using GC/TOF-MS on buffer and mitochondrial matrix fractions obtained prior to and after 20 min of palmitate catabolism (n = 7 mice/condition). Three palmitate concentrations (2, 9 and 19 µM; corresponding to low, intermediate and high oxidation rates) and 9 µM palmitate plus tricarboxylic acid (TCA) cycle and electron transport chain inhibitors were each tested and compared to zero palmitate control incubations. Paired comparisons of the 0 and 20 min samples were made by Student's t-test. False discovery rate were estimated and Type I error rates assigned. Major metabolite groups were organic acids, amines and amino acids, free fatty acids and sugar phosphates. Palmitate oxidation was associated with unique profiles of metabolites, a subset of which correlated to palmitate oxidation rate. In particular, palmitate oxidation rate was associated with distinct changes in the levels of TCA cycle intermediates within and effluxed from mitochondria. Conclusions/Significance This proof-of-principle study establishes that large-scale metabolomics methods can be applied to organelle-level models to discover metabolite patterns reflective of LCFA combustion, which may lead to identification of molecules linking muscle fat

  1. The role of the cell cycle in the cellular uptake of folate-modified poly(l-amino acid) micelles in a cell population

    NASA Astrophysics Data System (ADS)

    Tang, Jihui; Liu, Ziwei; Ji, Fenqi; Li, Yao; Liu, Junjie; Song, Jian; Li, Jun; Zhou, Jianping

    2015-12-01

    Nanoparticles are widely recognized as a vehicle for tumor-targeted therapies. There are many factors that can influence the uptake of nanoparticles, such as the size of the nanoparticles, and/or their shape, elasticity, surface charge and even the cell cycle phase. However, the influence of the cell cycle on the active targeting of a drug delivery system has been unknown until now. In this study, we initially investigated the folate receptor α (FR-α) expression in different phases of HeLa cells by flow cytometric and immunocytochemical methods. The results obtained showed that FR-α expression was cell cycle-dependent, i.e. the S cells' folate receptor expression was the highest as the cell progressed through its cycle. Then, we used folate modified poly(l-amino acid) micelles (FA-PM) as an example to investigate the influence of the cell cycle on the active targeting drug delivery system. The results obtained indicated that the uptake of FA-PM by cells was influenced by the cell cycle phase, and the S cells took up the greatest number of folate conjugated nanoparticles. Our findings suggest that future studies on ligand-mediated active targeting preparations should consider the cell cycle, especially when this system is used for a cell cycle-specific drug.

  2. Antiproliferative Effect of Ascorbic Acid Is Associated with the Inhibition of Genes Necessary to Cell Cycle Progression

    PubMed Central

    Belin, Sophie; Kaya, Ferdinand; Duisit, Ghislaine; Giacometti, Sarah; Ciccolini, Joseph; Fontés, Michel

    2009-01-01

    Background Ascorbic acid (AA), or Vitamin C, is most well known as a nutritional supplement with antioxidant properties. Recently, we demonstrated that high concentrations of AA act on PMP22 gene expression and partially correct the Charcot-Marie-Tooth disease phenotype in a mouse model. This is due to the capacity of AA, but not other antioxidants, to down-modulate cAMP intracellular concentration by a competitive inhibition of the adenylate cyclase enzymatic activity. Because of the critical role of cAMP in intracellular signalling, we decided to explore the possibility that ascorbic acid could modulate the expression of other genes. Methods and Findings Using human pangenomic microarrays, we found that AA inhibited the expression of two categories of genes necessary for cell cycle progression, tRNA synthetases and translation initiation factor subunits. In in vitro assays, we demonstrated that AA induced the S-phase arrest of proliferative normal and tumor cells. Highest concentrations of AA leaded to necrotic cell death. However, quiescent cells were not susceptible to AA toxicity, suggesting the blockage of protein synthesis was mainly detrimental in metabolically-active cells. Using animal models, we found that high concentrations of AA inhibited tumor progression in nude mice grafted with HT29 cells (derived from human colon carcinoma). Consistently, expression of tRNA synthetases and ieF2 appeared to be specifically decreased in tumors upon AA treatment. Conclusions AA has an antiproliferative activity, at elevated concentration that could be obtained using IV injection. This activity has been observed in vitro as well in vivo and likely results from the inhibition of expression of genes involved in protein synthesis. Implications for a clinical use in anticancer therapies will be discussed. PMID:19197388

  3. Diel cycling of zinc in a stream impacted by acid rock drainage: Initial results from a new in situ Zn analyzer

    USGS Publications Warehouse

    Chapin, T.P.; Nimick, D.A.; Gammons, C.H.; Wanty, R.B.

    2007-01-01

    Recent work has demonstrated that many trace metals undergo dramatic diel (24-h) cycles in near neutral pH streams with metal concentrations reproducibly changing up to 500% during the diel period (Nimick et al., 2003). To examine diel zinc cycles in streams affected by acid rock drainage, we have developed a novel instrument, the Zn-DigiScan, to continuously monitor in situ zinc concentrations in near real-time. Initial results from a 3-day deployment at Fisher Creek, Montana have demonstrated the ability of the Zn-DigiScan to record diel Zn cycling at levels below 100 ??g/l. Longer deployments of this instrument could be used to examine the effects of episodic events such as rainstorms and snowmelt pulses on zinc loading in streams affected by acid rock drainage. ?? Springer Science+Business Media B.V. 2006.

  4. Acute Carnosine Administration Increases Respiratory Chain Complexes and Citric Acid Cycle Enzyme Activities in Cerebral Cortex of Young Rats.

    PubMed

    Macedo, Levy W; Cararo, José H; Maravai, Soliany G; Gonçalves, Cinara L; Oliveira, Giovanna M T; Kist, Luiza W; Guerra Martinez, Camila; Kurtenbach, Eleonora; Bogo, Maurício R; Hipkiss, Alan R; Streck, Emilio L; Schuck, Patrícia F; Ferreira, Gustavo C

    2016-10-01

    Carnosine (β-alanyl-L-histidine) is an imidazole dipeptide synthesized in excitable tissues of many animals, whose biochemical properties include carbonyl scavenger, anti-oxidant, bivalent metal ion chelator, proton buffer, and immunomodulating agent, although its precise physiological role(s) in skeletal muscle and brain tissues in vivo remain unclear. The aim of the present study was to investigate the in vivo effects of acute carnosine administration on various aspects of brain bioenergetics of young Wistar rats. The activity of mitochondrial enzymes in cerebral cortex was assessed using a spectrophotometer, and it was found that there was an increase in the activities of complexes I-III and II-III and succinate dehydrogenase in carnosine-treated rats, as compared to vehicle-treated animals. However, quantitative real-time RT-PCR (RT-qPCR) data on mRNA levels of mitochondrial biogenesis-related proteins (nuclear respiratory factor 1 (Nrf1), peroxisome proliferator-activated receptor-γ coactivator 1-α (Ppargc1α), and mitochondrial transcription factor A (Tfam)) were not altered significantly and therefore suggest that short-term carnosine administration does not affect mitochondrial biogenesis. It was in agreement with the finding that immunocontent of respiratory chain complexes was not altered in animals receiving carnosine. These observations indicate that acute carnosine administration increases the respiratory chain and citric acid cycle enzyme activities in cerebral cortex of young rats, substantiating, at least in part, a neuroprotector effect assigned to carnosine against oxidative-driven disorders. PMID:26476839

  5. Involvement of apoptotic cell death and cell cycle perturbation in retinoic acid-induced cleft palate in mice

    SciTech Connect

    Okano, Junko . E-mail: okajun@anat1.med.kyoto-u.ac.jp; Suzuki, Shigehiko; Shiota, Kohei

    2007-05-15

    Retinoic acid (RA), a metabolite of vitamin A, plays a key role in a variety of biological processes and is essential for normal embryonic development. On the other hand, exogenous RA could cause cleft palate in offspring when it is given to pregnant animals at either the early or late phases of palatogenesis, but the pathogenetic mechanism of cleft palate caused by excess RA remains not fully elucidated. The aim of the present study was to investigate the effects of excess of RA on early palatogenesis in mouse fetuses and analyze the teratogenic mechanism, especially at the stage prior to palatal shelf elevation. We gave all-trans RA (100 mg/kg) orally to E11.5 ICR pregnant mice and observed the changes occurring in the palatal shelves of their fetuses. It was found that apoptotic cell death increased not only in the epithelium of the palatal shelves but also in the tongue primordium, which might affect tongue withdrawal movement during palatogenesis and impair the horizontal elevation of palatal shelves. In addition, RA was found to prevent the G{sub 1}/S progression of palatal mesenchymal cells through upregulation of p21 {sup Cip1}, leading to Rb hypophospholylation. Thus, RA appears to cause G{sub 1} arrest in palatal mesenchymal cells in a similar manner as in various cancer and embryonic cells. It is likely that apoptotic cell death and cell cycle disruption are involved in cleft palate formation induced by RA.

  6. Metaproteomics and ultrastructure characterization of Komagataeibacter spp. involved in high-acid spirit vinegar production.

    PubMed

    Andrés-Barrao, Cristina; Saad, Maged M; Cabello Ferrete, Elena; Bravo, Daniel; Chappuis, Marie-Luise; Ortega Pérez, Ruben; Junier, Pilar; Perret, Xavier; Barja, François

    2016-05-01

    Acetic acid bacteria (AAB) are widespread microorganisms in nature, extensively used in food industry to transform alcohols and sugar alcohols into their corresponding organic acids. Specialized strains are used in the production of vinegar through the oxidative transformation of ethanol into acetic acid. The main AAB involved in the production of high-acid vinegars using the submerged fermentation method belong to the genus Komagataeibacter, characterized by their higher ADH stability and activity, and higher acetic acid resistance (15-20%), compared to other AAB. In this work, the bacteria involved in the production of high-acid spirit vinegar through a spontaneous acetic acid fermentation process was studied. The analysis using a culture-independent approach revealed a homogeneous bacterial population involved in the process, identified as Komagataeibacter spp. Differentially expressed proteins during acetic acid fermentation were investigated by using 2D-DIGE and mass spectrometry. Most of these proteins were functionally related to stress response, the TCA cycle and different metabolic processes. In addition, scanning and transmission electron microscopy and specific staining of polysaccharide SDS-PAGE gels confirmed that Komagataeibacter spp. lacked the characteristic polysaccharide layer surrounding the outer membrane that has been previously reported to have an important role in acetic acid resistance in the genus Acetobacter. PMID:26742622

  7. The effect of biotin on the production of succinic acid by Anaerobiospirillum succiniciproducens

    SciTech Connect

    Nghiem, N.P.; Davison, B.H.; Thompson, J.E.

    1995-07-01

    Succinic acid is an intermediate of the tricarboxylic acid (TCA) cycle, and therefore, is found in almost all plant and animal cells, albeit at very low concentrations. It has a very wide usage range, which includes applications in agriculture, food, medicine, plastics, cosmetics, textiles, plating and waste-gas scrubbing. Succinic acid currently is produced commercially by chemical processes. A fermentation process for its production is of great interest because in such process, renewable resources such as corn-derived glucose can be used as starting material. There is not a current biological process for the commercial production of succinic acid. Extensive efforts have been devoted to the isolation and screening of succinic acid-producing microorganisms. The anaerobic bacterium, Anaerobiospirillum succiniciproducens, is considered among the best direct succinic acid producers. A number of patents concerning the production of succinic acid by this organism have been issued. Our first attempt to develop a biological process for the production of succinic acid by A. succiniciproducens involved fermentation media improvement, in particular the use of supplemented nutrients. In this note, we show that higher yield of succinic acid could be achieved by supplementing the fermentation media with biotin, as a potential nutrient supplement representative.

  8. ROCK inhibitor Y-27632 inhibits the growth, migration, and invasion of Tca8113 and CAL-27 cells in tongue squamous cell carcinoma.

    PubMed

    Wang, Zhi-Ming; Yang, Dong-Sheng; Liu, Jie; Liu, Hong-Bo; Ye, Ming; Zhang, Yu-Fei

    2016-03-01

    The objective of this study is to determine the effects of Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor Y-27632 on the growth, invasion, and migration of Tca8113 and CAL-27 cells in tongue squamous cell carcinoma (TSCC). The methods of the study are as follows: After being routinely cultured for 24 h, Tca8113 and CAL-27 cells were treated with Y-27632 solution. The morphological change of Y-27632-treated cells was observed under an optical microscope and an inverted microscope; MTT assay was performed to measure the optical density (OD) of cells and calculate cell growth inhibition rate; the change of apoptosis was detected by AnnexinV-FITC/PI assay; cell invasion and migration were measured by Transwell assay. The results were as follows: (1) With increasing concentration of Y-27632, cell morphology changed and cell apoptosis appeared; (2) MTT assay showed that inhibition effect of Y-27632 on Tca8113 and CAL-27 cells was enhanced with increasing concentrations and time (all P < 0.01); (3) Apoptosis showed that, compared with controls, the number of apoptosis cells in experimental groups was significantly increased (all P < 0.01). Apoptosis rate was elevated with increasing concentrations of Y-27632; (4) Transwell assay showed, after a treatment with Y-27632, the number of migrated and invaded Tca8113 and CAL-27 cells in each group was statistically different (all P < 0.01); compared with controls, the number of migrated cell in groups treated with Y-27632 was decreased and less Tca8113 and CAL-27 cells in experimental groups passed through polycarbonate membrane (all P < 0.05). The study concludes that Y-27632 can inhibit the growth, invasion, and migration of Tca8113 and CAL-27 cells, suggesting that Y-27632 may be therapeutically useful in TSCC. PMID:26468018

  9. Aircraft Emission Scenarios Projected in Year 2015 for the NASA Technology Concept Aircraft (TCA) High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Baughcum, Steven L.; Henderson, Stephen C.

    1998-01-01

    This report describes the development of a three-dimensional database of aircraft fuel burn and emissions (fuel burned, NOx, CO, and hydrocarbons) from projected fleets of high speed civil transports (HSCTs) on a universal airline network. Inventories for 500 and 1000 HSCT fleets, as well as the concurrent subsonic fleets, were calculated. The HSCT scenarios are calculated using the NASA technology concept airplane (TCA) and update an earlier report. These emissions inventories are available for use by atmospheric scientists conducting the Atmospheric Effects of Stratospheric Aircraft (AESA) modeling studies. Fuel burned and emissions of nitrogen oxides (NOx as NO2), carbon monoxide, and hydrocarbons have been calculated on a 1 degree latitude x 1 degree longitude x 1 kilometer pressure altitude grid and delivered to NASA as electronic files.

  10. Reproductive cycle and seasonal variations in lipid content and fatty acid composition in gonad of the cockle Fulvia mutica in relation to temperature and food

    NASA Astrophysics Data System (ADS)

    Liu, Wenguang; Li, Qi; Kong, Lingfeng

    2013-09-01

    From March 2004 to February 2005, seasonal variations in lipid content and fatty acid composition of gonad of the cockle Fulvia mutica (Reeve) were studied on the eastern coast of China in relation to the reproductive cycle and environment conditions ( e.g., temperature and food availability). Histological analysis as well as lipid and fatty acid analyses were performed on neutral and polar lipids of the gonad. Results showed that gametogenesis occurred in winter and spring at the expense of lipids previously accumulated in summer and autumn, whereas spawning occurred in summer (20.4-24.6°C). The seasonal variation in lipid content was similar to that of the mean oocyte diameter. In both neutral and polar lipids, the 20:5n-3 and 22:6n-3 levels were relatively higher than saturated fatty acids, and polyunsaturated fatty acids were abundant, with series n-3 as the predominant component. Seasonal variations in the 20:5n-3 and 22:6n-3 levels and the principal n-3 fatty acids were clearly related to the reproductive cycle. The Σ(n-3) and Σ(n-6) values were relatively high during January-May, and the associated unsaturation index was significantly higher than that in other months. The results suggest that fatty acids play an important role in the gametogenesis of F. mutica.

  11. Comparative Transcriptome Analysis Reveals Different Molecular Mechanisms of Bacillus coagulans 2-6 Response to Sodium Lactate and Calcium Lactate during Lactic Acid Production

    PubMed Central

    Qin, Jiayang; Wang, Xiuwen; Wang, Landong; Zhu, Beibei; Zhang, Xiaohua; Yao, Qingshou; Xu, Ping

    2015-01-01

    Lactate production is enhanced by adding calcium carbonate or sodium hydroxide during fermentation. However, Bacillus coagulans 2-6 can produce more than 180 g/L L-lactic acid when calcium lactate is accumulated, but less than 120 g/L L-lactic acid when sodium lactate is formed. The molecular mechanisms by which B. coagulans responds to calcium lactate and sodium lactate remain unclear. In this study, comparative transcriptomic methods based on high-throughput RNA sequencing were applied to study gene expression changes in B. coagulans 2-6 cultured in non-stress, sodium lactate stress and calcium lactate stress conditions. Gene expression profiling identified 712 and 1213 significantly regulated genes in response to calcium lactate stress and sodium lactate stress, respectively. Gene ontology assignments of the differentially expressed genes were performed. KEGG pathway enrichment analysis revealed that ‘ATP-binding cassette transporters’ were significantly affected by calcium lactate stress, and ‘amino sugar and nucleotide sugar metabolism’ was significantly affected by sodium lactate stress. It was also found that lactate fermentation was less affected by calcium lactate stress than by sodium lactate stress. Sodium lactate stress had negative effect on the expression of ‘glycolysis/gluconeogenesis’ genes but positive effect on the expression of ‘citrate cycle (TCA cycle)’ genes. However, calcium lactate stress had positive influence on the expression of ‘glycolysis/gluconeogenesis’ genes and had minor influence on ‘citrate cycle (TCA cycle)’ genes. Thus, our findings offer new insights into the responses of B. coagulans to different lactate stresses. Notably, our RNA-seq dataset constitute a robust database for investigating the functions of genes induced by lactate stress in the future and identify potential targets for genetic engineering to further improve L-lactic acid production by B. coagulans. PMID:25875592

  12. Bile acids regulate intestinal cell proliferation by modulating EGFR and FXR signaling.

    PubMed

    Dossa, Avafia Y; Escobar, Oswaldo; Golden, Jamie; Frey, Mark R; Ford, Henri R; Gayer, Christopher P

    2016-01-15

    Bile acids (BAs) are synthesized in the liver and secreted into the intestine. In the lumen, enteric bacteria metabolize BAs from conjugated, primary forms into more toxic unconjugated, secondary metabolites. Secondary BAs can be injurious to the intestine and may contribute to disease. The epidermal growth factor receptor (EGFR) and the nuclear farnesoid X receptor (FXR) are known to interact with BAs. In this study we examined the effects of BAs on intestinal epithelial cell proliferation and investigated the possible roles for EGFR and FXR in these effects. We report that taurine-conjugated cholic acid (TCA) induced proliferation, while its unconjugated secondary counterpart deoxycholic acid (DCA) inhibited proliferation. TCA stimulated phosphorylation of Src, EGFR, and ERK 1/2. Pharmacological blockade of any of these pathways or genetic ablation of EGFR abrogated TCA-stimulated proliferation. Interestingly, Src or EGFR inhibitors eliminated TCA-induced phosphorylation of both molecules, suggesting that their activation is interdependent. In contrast to TCA, DCA exposure diminished EGFR phosphorylation, and pharmacological or siRNA blockade of FXR abolished DCA-induced inhibition of proliferation. Taken together, these results suggest that TCA induces intestinal cell proliferation via Src, EGFR, and ERK activation. In contrast, DCA inhibits proliferation via an FXR-dependent mechanism that may include downstream inactivation of the EGFR/Src/ERK pathway. Since elevated secondary BA levels are the result of specific bacterial modification, this may provide a mechanism through which an altered microbiota contributes to normal or abnormal intestinal epithelial cell proliferation. PMID:26608185

  13. Species Differences in Hepatobiliary Disposition of Taurocholic Acid in Human and Rat Sandwich-Cultured Hepatocytes: Implications for Drug-Induced Liver Injury

    PubMed Central

    Yang, Kyunghee; Pfeifer, Nathan D.; Köck, Kathleen

    2015-01-01

    The bile salt export pump (BSEP) plays an important role in bile acid excretion. Impaired BSEP function may result in liver injury. Bile acids also undergo basolateral efflux, but the relative contributions of biliary (CLBile) versus basolateral efflux (CLBL) clearance to hepatocellular bile acid excretion have not been determined. In the present study, taurocholic acid (TCA; a model bile acid) disposition was characterized in human and rat sandwich-cultured hepatocytes (SCH) combined with pharmacokinetic modeling. In human SCH, biliary excretion of TCA predominated (CLBile = 0.14 ± 0.04 ml/min per g liver; CLBL = 0.042 ± 0.019 ml/min per g liver), whereas CLBile and CLBL contributed approximately equally to TCA hepatocellular excretion in rat SCH (CLBile = 0.34 ± 0.07 ml/min per g liver; CLBL = 0.26 ± 0.07 ml/min per g liver). Troglitazone decreased TCA uptake, CLBile, and CLBL; membrane vesicle assays revealed for the first time that the major metabolite, troglitazone sulfate, was a noncompetitive inhibitor of multidrug resistance–associated protein 4, a basolateral bile acid efflux transporter. Simulations revealed that decreased CLBile led to a greater increase in hepatic TCA exposure in human than in rat SCH. A decrease in both excretory pathways (CLBile and CLBL) exponentially increased hepatic TCA in both species, suggesting that 1) drugs that inhibit both pathways may have a greater risk for hepatotoxicity, and 2) impaired function of an alternate excretory pathway may predispose patients to hepatotoxicity when drugs that inhibit one pathway are administered. Simulations confirmed the protective role of uptake inhibition, suggesting that a drug’s inhibitory effects on bile acid uptake also should be considered when evaluating hepatotoxic potential. Overall, the current study precisely characterized basolateral efflux of TCA, revealed species differences in hepatocellular TCA efflux pathways, and provided insights about altered hepatic bile acid

  14. Species differences in hepatobiliary disposition of taurocholic acid in human and rat sandwich-cultured hepatocytes: implications for drug-induced liver injury.

    PubMed

    Yang, Kyunghee; Pfeifer, Nathan D; Köck, Kathleen; Brouwer, Kim L R

    2015-05-01

    The bile salt export pump (BSEP) plays an important role in bile acid excretion. Impaired BSEP function may result in liver injury. Bile acids also undergo basolateral efflux, but the relative contributions of biliary (CLBile) versus basolateral efflux (CLBL) clearance to hepatocellular bile acid excretion have not been determined. In the present study, taurocholic acid (TCA; a model bile acid) disposition was characterized in human and rat sandwich-cultured hepatocytes (SCH) combined with pharmacokinetic modeling. In human SCH, biliary excretion of TCA predominated (CLBile = 0.14 ± 0.04 ml/min per g liver; CLBL = 0.042 ± 0.019 ml/min per g liver), whereas CLBile and CLBL contributed approximately equally to TCA hepatocellular excretion in rat SCH (CLBile = 0.34 ± 0.07 ml/min per g liver; CLBL = 0.26 ± 0.07 ml/min per g liver). Troglitazone decreased TCA uptake, CLBile, and CLBL; membrane vesicle assays revealed for the first time that the major metabolite, troglitazone sulfate, was a noncompetitive inhibitor of multidrug resistance-associated protein 4, a basolateral bile acid efflux transporter. Simulations revealed that decreased CLBile led to a greater increase in hepatic TCA exposure in human than in rat SCH. A decrease in both excretory pathways (CLBile and CLBL) exponentially increased hepatic TCA in both species, suggesting that 1) drugs that inhibit both pathways may have a greater risk for hepatotoxicity, and 2) impaired function of an alternate excretory pathway may predispose patients to hepatotoxicity when drugs that inhibit one pathway are administered. Simulations confirmed the protective role of uptake inhibition, suggesting that a drug's inhibitory effects on bile acid uptake also should be considered when evaluating hepatotoxic potential. Overall, the current study precisely characterized basolateral efflux of TCA, revealed species differences in hepatocellular TCA efflux pathways, and provided insights about altered hepatic bile acid exposure

  15. Trichloroacetic acid in urine as biological exposure equivalent for low exposure concentrations of trichloroethene.

    PubMed

    Csanády, György A; Göen, Thomas; Klein, Dominik; Drexler, Hans; Filser, Johannes G

    2010-11-01

    A urinary trichloroacetic acid (TCA) concentration of 100 mg/l at the end of the last work shift (8 h/day, 5 days/week) of the week has been established in workers as exposure equivalent for the carcinogenic substance trichloroethene (EKA for TRI) at an exposure concentration of 50 ppm TRI. Due to the continuous reduction of atmospheric TRI concentrations during the last years, the quantitative relation given by the EKA for TRI is revised for exposures to low TRI concentrations. A physiological two-compartment model is presented by which the urinary TCA concentrations are calculated that result from inhaled TRI in humans. The model contains one compartment for trichloroethanol (TCE) and one for TCA. Inhaled TRI is metabolized to TCA and to TCE. The latter is in part further oxidized to TCA. Urinary elimination of TCA is modeled to obey first order kinetics. All required model parameters were taken form the literature. In order to evaluate the model performance on the urinary TCA excretion at low exposure concentrations, predicted urinary TCA concentrations were compared with data obtained in two volunteer studies and in one field study. The model was evaluated at exposure concentrations as low as 12.5 ppm TRI. It is demonstrated that the correlation described by the hitherto used EKA for TRI is also valid at low TRI concentrations. For TRI exposure concentrations of 0.6 and 6 ppm, the resulting urinary TCA concentrations at the end of the last work shift of a week are predicted to be 1.2 and 12 mg/l, respectively. PMID:20414643

  16. Microprocessor-controlled phase analysis for a 2-mm microwave interferometer on the TCA tokamak

    SciTech Connect

    Lister, J.B.; Means, R.W.; Oberson, P.

    1982-05-01

    The method of phase analysis is presented for a 2-mm microwave interferometer built to measure the plasma density in a tokamak. Use is made of a fast phase shifter (FPS) constructed from a switchable four-port circulator to resolve the phase ambiguity inherent in a simple interferometer. The phase between 0--2..pi.. is calculated by a microprocessor accessing a look-up table and the total phase is calculated by taking the 0 to 2..pi.. crossings into consideration. It is software controlled and the complete sampling and analysis cycle takes 24 ..mu..s which is sufficiently rapid for the application considered. The phase information is available in analog and digital form.

  17. Microprocessor-controlled phase analysis for a 2-mm microwave interferometer on the TCA tokamak

    NASA Astrophysics Data System (ADS)

    Lister, J. B.; Means, R. W.; Oberson, P.

    1982-05-01

    The method of phase analysis is presented for a 2-mm microwave interferometer built to measure the plasma density in a tokamak. Use is made of a fast phase shifter (FPS) constructed from a switchable four-port circulator to resolve the phase ambiguity inherent in a simple interferometer. The phase between 0-2π is calculated by a microprocessor accessing a look-up table and the total phase is calculated by taking the 0 to 2π crossings into consideration. It is software controlled and the complete sampling and analysis cycle takes 24 μs which is sufficiently rapid for the application considered. The phase information is available in analog and digital form.

  18. Notch stimulates growth by direct regulation of genes involved in the control of glycolysis and the tricarboxylic acid cycle.

    PubMed

    Slaninova, Vera; Krafcikova, Michaela; Perez-Gomez, Raquel; Steffal, Pavel; Trantirek, Lukas; Bray, Sarah J; Krejci, Alena

    2016-02-01

    Glycolytic shift is a characteristic feature of rapidly proliferating cells, such as cells during development and during immune response or cancer cells, as well as of stem cells. It results in increased glycolysis uncoupled from mitochondrial respiration, also known as the Warburg effect. Notch signalling is active in contexts where cells undergo glycolytic shift. We decided to test whether metabolic genes are direct transcriptional targets of Notch signalling and whether upregulation of metabolic genes can help Notch to induce tissue growth under physiological conditions and in conditions of Notch-induced hyperplasia. We show that genes mediating cellular metabolic changes towards the Warburg effect are direct transcriptional targets of Notch signalling. They include genes encoding proteins involved in glucose uptake, glycolysis, lactate to pyruvate conversion and repression of the tricarboxylic acid cycle. The direct transcriptional upregulation of metabolic genes is PI3K/Akt independent and occurs not only in cells with overactivated Notch but also in cells with endogenous levels of Notch signalling and in vivo. Even a short pulse of Notch activity is able to elicit long-lasting metabolic changes resembling the Warburg effect. Loss of Notch signalling in Drosophila wing discs as well as in human microvascular cells leads to downregulation of glycolytic genes. Notch-driven tissue overgrowth can be rescued by downregulation of genes for glucose metabolism. Notch activity is able to support growth of wing during nutrient-deprivation conditions, independent of the growth of the rest of the body. Notch is active in situations that involve metabolic reprogramming, and the direct regulation of metabolic genes may be a common mechanism that helps Notch to exert its effects in target tissues. PMID:26887408

  19. Notch stimulates growth by direct regulation of genes involved in the control of glycolysis and the tricarboxylic acid cycle

    PubMed Central

    Slaninova, Vera; Krafcikova, Michaela; Perez-Gomez, Raquel; Steffal, Pavel; Trantirek, Lukas; Bray, Sarah J.

    2016-01-01

    Glycolytic shift is a characteristic feature of rapidly proliferating cells, such as cells during development and during immune response or cancer cells, as well as of stem cells. It results in increased glycolysis uncoupled from mitochondrial respiration, also known as the Warburg effect. Notch signalling is active in contexts where cells undergo glycolytic shift. We decided to test whether metabolic genes are direct transcriptional targets of Notch signalling and whether upregulation of metabolic genes can help Notch to induce tissue growth under physiological conditions and in conditions of Notch-induced hyperplasia. We show that genes mediating cellular metabolic changes towards the Warburg effect are direct transcriptional targets of Notch signalling. They include genes encoding proteins involved in glucose uptake, glycolysis, lactate to pyruvate conversion and repression of the tricarboxylic acid cycle. The direct transcriptional upregulation of metabolic genes is PI3K/Akt independent and occurs not only in cells with overactivated Notch but also in cells with endogenous levels of Notch signalling and in vivo. Even a short pulse of Notch activity is able to elicit long-lasting metabolic changes resembling the Warburg effect. Loss of Notch signalling in Drosophila wing discs as well as in human microvascular cells leads to downregulation of glycolytic genes. Notch-driven tissue overgrowth can be rescued by downregulation of genes for glucose metabolism. Notch activity is able to support growth of wing during nutrient-deprivation conditions, independent of the growth of the rest of the body. Notch is active in situations that involve metabolic reprogramming, and the direct regulation of metabolic genes may be a common mechanism that helps Notch to exert its effects in target tissues. PMID:26887408

  20. Functions of the Membrane-Associated and Cytoplasmic Malate Dehydrogenases in the Citric Acid Cycle of Corynebacterium glutamicum

    PubMed Central

    Molenaar, Douwe; van der Rest, Michel E.; Drysch, André; Yücel, Raif

    2000-01-01

    Like many other bacteria, Corynebacterium glutamicum possesses two types of l-malate dehydrogenase, a membrane-associated malate:quinone oxidoreductase (MQO; EC 1.1.99.16) and a cytoplasmic malate dehydrogenase (MDH; EC 1.1.1.37) The regulation of MDH and of the three membrane-associated dehydrogenases MQO, succinate dehydrogenase (SDH), and NADH dehydrogenase was investigated. MQO, MDH, and SDH activities are regulated coordinately in response to the carbon and energy source for growth. Compared to growth on glucose, these activities are increased during growth on lactate, pyruvate, or acetate, substrates which require high citric acid cycle activity to sustain growth. The simultaneous presence of high activities of both malate dehydrogenases is puzzling. MQO is the most important malate dehydrogenase in the physiology of C. glutamicum. A mutant with a site-directed deletion in the mqo gene does not grow on minimal medium. Growth can be partially restored in this mutant by addition of the vitamin nicotinamide. In contrast, a double mutant lacking MQO and MDH does not grow even in the presence of nicotinamide. Apparently, MDH is able to take over the function of MQO in an mqo mutant, but this requires the presence of nicotinamide in the growth medium. It is shown that addition of nicotinamide leads to a higher intracellular pyridine nucleotide concentration, which probably enables MDH to catalyze malate oxidation. Purified MDH from C. glutamicum catalyzes oxaloacetate reduction much more readily than malate oxidation at physiological pH. In a reconstituted system with isolated membranes and purified MDH, MQO and MDH catalyze the cyclic conversion of malate and oxaloacetate, leading to a net oxidation of NADH. Evidence is presented that this cyclic reaction also takes place in vivo. As yet, no phenotype of an mdh deletion alone was observed, which leaves a physiological function for MDH in C. glutamicum obscure. PMID:11092846

  1. Comparative proteomic analysis of engineered Saccharomyces cerevisiae with enhanced free fatty acid accumulation.

    PubMed

    Chen, Liwei; Lee, Jaslyn Jie Lin; Zhang, Jianhua; Chen, Wei Ning

    2016-02-01

    The engineered Saccharomyces cerevisiae strain △faa1△faa4 [Acot5s] was demonstrated to accumulate more free fatty acids (FFA) previously. Here, comparative proteomic analysis was performed to get a global overview of metabolic regulation in the strain. Over 500 proteins were identified, and 82 of those proteins were found to change significantly in the engineered strains. Proteins involved in glycolysis, acetate metabolism, fatty acid synthesis, TCA cycle, glyoxylate cycle, the pentose phosphate pathway, respiration, transportation, and stress response were found to be upregulated in △faa1△faa4 [Acot5s] as compared to the wild type. On the other hand, proteins involved in glycerol, ethanol, ergosterol, and cell wall synthesis were downregulated. Taken together with our metabolite analysis, our results showed that the disruption of Faa1 and Faa4 and expression of Acot5s in the engineered strain △faa1△faa4 [Acot5s] not only relieved the feedback inhibition of fatty acyl-CoAs on fatty acid synthesis, but also caused a major metabolic rearrangement. The rearrangement redirected carbon flux toward the pathways which generate the essential substrates and cofactors for fatty acid synthesis, such as acetyl-CoA, ATP, and NADPH. Therefore, our results help shed light on the mechanism for the increased production of fatty acids in the engineered strains, which is useful in providing information for future studies in biofuel production. PMID:26450510

  2. Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb's cycle flux independent of ATP synthesis

    SciTech Connect

    Cline, Gary W.; Pongratz, Rebecca L.; Zhao, Xiaojian; Papas, Klearchos K.

    2011-11-11

    Highlights: Black-Right-Pointing-Pointer We studied media effects on mechanisms of insulin secretion of INS-1 cells. Black-Right-Pointing-Pointer Insulin secretion was higher in DMEM than KRB despite identical ATP synthesis rates. Black-Right-Pointing-Pointer Insulin secretion rates correlated with rates of anaplerosis and TCA cycle. Black-Right-Pointing-Pointer Mitochondria metabolism and substrate cycles augment secretion signal of ATP. -- Abstract: Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with {sup 31}P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by {sup 13}C NMR isotopomer analysis of the fate of [U-{sup 13}C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15 mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found

  3. Capacitive carbon and electrochemical lead electrode systems at the negative plates of lead-acid batteries and elementary processes on cycling

    NASA Astrophysics Data System (ADS)

    Pavlov, D.; Nikolov, P.

    2013-11-01

    Batteries in hybrid electric vehicles operate in High-Rate Partial-State-of-Charge (HRPSoC) cycling duty. To make lead-acid batteries suitable for this duty, carbon is added to the negative active material. As a result of this technological change, two electrical systems form at the negative plates: (a) a capacitive carbon system comprising high-rate charging and discharging of the electric double layer; low Ah capacity, and (b) a lead electrochemical system, comprising oxidation of Pb to PbSO4 during discharge and vice versa during charge; this system is slow to accept charge, but has high Ah capacity. Through cycling lead-acid cells under HRPSoC conditions with short current pulses of various durations we have established that the processes involved in the capacitive system proceed highly reversibly and complete hundreds of thousands HRPSoC cycles. The number of cycles achieved by the electrochemical system is limited to tens of thousands and lead to progressive sulfation. Carbon added to the negative active material changes the latter's structure. The specific surface of NAM increases and the median pore radius decreases. Some carbon additives may reduce the radius of the pores in NAM to membrane sizes, which may change the chemistry of the electrochemical system.

  4. The routes and kinetics of trichloroacetic acid uptake and elimination in Sitka spruce ( Picea sitchensis) saplings via atmospheric deposition pathways

    NASA Astrophysics Data System (ADS)

    Heal, M. R.; Dickey, C. A.; Cape, J. N.; Heal, K. V.

    A major flux of trichloroacetic acid (TCA) to forests is via wet deposition, but the transfer of TCA into tree foliage may occur by an above- or below-ground pathway. To investigate the routes and kinetics of TCA uptake, two groups of 10 Sitka spruce saplings (with an equivalent number of controls) were exposed to a single application of 200 μg TCA in solution, either to the soil only, or sprayed as a mist to the foliage only. The needle foliage was subsequently analysed regularly for TCA for 3 months during the growing season. Significant uptake into current year ( C) needles was observed from both routes just a few days after application, providing direct evidence of an above-ground uptake route. Uptake of TCA was also observed in the previous year needle class ( C+1). Kinetic modelling of the data indicated that the half-life for within-needle elimination (during the growing season) was ˜50±30 days. Most of the applied TCA appeared to be degraded before uptake, either in the soil, or externally on the sapling foliage.

  5. The effect of a tertiary bile acid, taurocholic acid, on the morphology and physical characteristics of microencapsulated probucol: potential applications in diabetes: a characterization study.

    PubMed

    Mooranian, Armin; Negrulj, Rebecca; Arfuso, Frank; Al-Salami, Hani

    2015-10-01

    In recent studies, we designed multi-compartmental microcapsules as a platform for the targeted oral delivery of lipophilic drugs in an animal model of type 2 diabetes (T2D). Probucol (PB) is a highly lipophilic, antihyperlipidemic drug with potential antidiabetic effects. PB has low bioavailability and high inter-individual variations in absorption, which limits its clinical applications. In a new study, the bile acid, taurocholic acid (TCA), exerted permeation enhancing effects in vivo. Accordingly, this study aimed to design and characterize TCA-based PB microcapsules and examine the effects of TCA on the microcapsules' morphology, stability, and release profiles. Microcapsules were prepared using the polymer sodium alginate (SA). Two types of microcapsules were produced, one without TCA (PB-SA, control) and one with TCA (PB-TCA-SA, test). Microcapsules were studied in terms of morphology, surface structure and composition, size, drug contents, cross-sectional imaging (using microtomography (Micro-CT) analysis), Zeta potential, thermal and chemical profiles, rheological parameters, swelling, mechanical strength, and release studies at various temperature and pH values. The production yield and the encapsulation efficiency were also studied together with in vitro efficacy testing of cell viability at various glucose concentrations and insulin and TNF-α production using clonal-mouse pancreatic β-cells. PB-TCA-SA microcapsules showed uniform structure and even distribution of TCA within the microcapsules. Drug contents, Zeta potential, size, rheological parameters, production yield, and the microencapsulation efficiency remained similar after TCA addition. In vitro testing showed PB-TCA-SA microcapsules improved β-cell survival under hyperglycemic states and reduced the pro-inflammatory cytokine TNF-α while increasing insulin secretions compared with PB-SA microcapsules. PB-TCA-SA microcapsules also showed good stability, better mechanical (p < 0.01) and

  6. Ustilago maydis produces itaconic acid via the unusual intermediate trans-aconitate.

    PubMed

    Geiser, Elena; Przybilla, Sandra K; Friedrich, Alexandra; Buckel, Wolfgang; Wierckx, Nick; Blank, Lars M; Bölker, Michael

    2016-01-01

    Itaconic acid is an important biomass-derived chemical building block but has also recently been identified as a metabolite produced in mammals, which has antimicrobial activity. The biosynthetic pathway of itaconic acid has been elucidated in the ascomycetous fungus Aspergillus terreus and in human macrophages. In both organisms itaconic acid is generated by decarboxylation of the tricarboxylic acid (TCA) cycle intermediate cis-aconitate. Here, we show that the basidiomycetous fungus Ustilago maydis uses an alternative pathway and produces itaconic acid via trans-aconitate, the thermodynamically favoured isomer of cis-aconitate. We have identified a gene cluster that contains all genes involved in itaconic acid formation. Trans-aconitate is generated from cis-aconitate by a cytosolic aconitate-Δ-isomerase (Adi1) that belongs to the PrpF family of proteins involved in bacterial propionate degradation. Decarboxylation of trans-aconitate is catalyzed by a novel enzyme, trans-aconitate decarboxylase (Tad1). Tad1 displays significant sequence similarity with bacterial 3-carboxy-cis,cis-muconate lactonizing enzymes (CMLE). This suggests that U. maydis has evolved an alternative biosynthetic pathway for itaconate production using the toxic intermediate trans-aconitate. Overexpression of a pathway-specific transcription factor (Ria1) or a mitochondrial tricarboxylic acid transporter (Mtt1) resulted in a twofold increase in itaconate yield. Therefore, our findings offer new strategies for biotechnological production of this valuable biomass-derived chemical. PMID:26639528

  7. SPECIES AND STRAIN SENSITIVITY TO THE INDUCTION OF PEROXISOME PROLIFERATION BY CHLOROACETIC ACIDS

    EPA Science Inventory

    B6C3F1 mice and Sprague-Dawley rats were provided drinking water containing 6 - 31 mM trichloroacetic acid (TCA), 8 - 39 mM dichloroacetic acid (DCA) or 11 - 33 mM monochloroacetic acid (MCA) for 14 days. CA and DCA, but not MCA, increased the mouse relative liver weight in a dos...

  8. Regulation of Life Cycle Checkpoints and Developmental Activation of Infective Larvae in Strongyloides stercoralis by Dafachronic Acid

    PubMed Central

    Pilgrim, Adeiye A.; Nolan, Thomas J.; Wang, Zhu; Kliewer, Steven A.; Mangelsdorf, David J.; Lok, James B.

    2016-01-01

    The complex life cycle of the parasitic nematode Strongyloides stercoralis leads to either developmental arrest of infectious third-stage larvae (iL3) or growth to reproductive adults. In the free-living nematode Caenorhabditis elegans, analogous determination between dauer arrest and reproductive growth is governed by dafachronic acids (DAs), a class of steroid hormones that are ligands for the nuclear hormone receptor DAF-12. Biosynthesis of DAs requires the cytochrome P450 (CYP) DAF-9. We tested the hypothesis that DAs also regulate S. stercoralis development via DAF-12 signaling at three points. First, we found that 1 μM Δ7-DA stimulated 100% of post-parasitic first-stage larvae (L1s) to develop to free-living adults instead of iL3 at 37°C, while 69.4±12.0% (SD) of post-parasitic L1s developed to iL3 in controls. Second, we found that 1 μM Δ7-DA prevented post-free-living iL3 arrest and stimulated 85.2±16.9% of larvae to develop to free-living rhabditiform third- and fourth-stages, compared to 0% in the control. This induction required 24–48 hours of Δ7-DA exposure. Third, we found that the CYP inhibitor ketoconazole prevented iL3 feeding in host-like conditions, with only 5.6±2.9% of iL3 feeding in 40 μM ketoconazole, compared to 98.8±0.4% in the positive control. This inhibition was partially rescued by Δ7-DA, with 71.2±16.4% of iL3 feeding in 400 nM Δ7-DA and 35 μM ketoconazole, providing the first evidence of endogenous DA production in S. stercoralis. We then characterized the 26 CYP-encoding genes in S. stercoralis and identified a homolog with sequence and developmental regulation similar to DAF-9. Overall, these data demonstrate that DAF-12 signaling regulates S. stercoralis development, showing that in the post-parasitic generation, loss of DAF-12 signaling favors iL3 arrest, while increased DAF-12 signaling favors reproductive development; that in the post-free-living generation, absence of DAF-12 signaling is crucial for iL3 arrest

  9. Regulation of Life Cycle Checkpoints and Developmental Activation of Infective Larvae in Strongyloides stercoralis by Dafachronic Acid.

    PubMed

    Albarqi, Mennatallah M Y; Stoltzfus, Jonathan D; Pilgrim, Adeiye A; Nolan, Thomas J; Wang, Zhu; Kliewer, Steven A; Mangelsdorf, David J; Lok, James B

    2016-01-01

    The complex life cycle of the parasitic nematode Strongyloides stercoralis leads to either developmental arrest of infectious third-stage larvae (iL3) or growth to reproductive adults. In the free-living nematode Caenorhabditis elegans, analogous determination between dauer arrest and reproductive growth is governed by dafachronic acids (DAs), a class of steroid hormones that are ligands for the nuclear hormone receptor DAF-12. Biosynthesis of DAs requires the cytochrome P450 (CYP) DAF-9. We tested the hypothesis that DAs also regulate S. stercoralis development via DAF-12 signaling at three points. First, we found that 1 μM Δ7-DA stimulated 100% of post-parasitic first-stage larvae (L1s) to develop to free-living adults instead of iL3 at 37°C, while 69.4±12.0% (SD) of post-parasitic L1s developed to iL3 in controls. Second, we found that 1 μM Δ7-DA prevented post-free-living iL3 arrest and stimulated 85.2±16.9% of larvae to develop to free-living rhabditiform third- and fourth-stages, compared to 0% in the control. This induction required 24-48 hours of Δ7-DA exposure. Third, we found that the CYP inhibitor ketoconazole prevented iL3 feeding in host-like conditions, with only 5.6±2.9% of iL3 feeding in 40 μM ketoconazole, compared to 98.8±0.4% in the positive control. This inhibition was partially rescued by Δ7-DA, with 71.2±16.4% of iL3 feeding in 400 nM Δ7-DA and 35 μM ketoconazole, providing the first evidence of endogenous DA production in S. stercoralis. We then characterized the 26 CYP-encoding genes in S. stercoralis and identified a homolog with sequence and developmental regulation similar to DAF-9. Overall, these data demonstrate that DAF-12 signaling regulates S. stercoralis development, showing that in the post-parasitic generation, loss of DAF-12 signaling favors iL3 arrest, while increased DAF-12 signaling favors reproductive development; that in the post-free-living generation, absence of DAF-12 signaling is crucial for iL3 arrest

  10. Compound specific amino acid δ15N in marine sediments: A new approach for studies of the marine nitrogen cycle

    NASA Astrophysics Data System (ADS)

    Batista, Fabian C.; Ravelo, A. Christina; Crusius, John; Casso, Michael A.; McCarthy, Matthew D.

    2014-10-01

    The nitrogen (N) isotopic composition (δ15N) of bulk sedimentary N (δ15Nbulk) is a common tool for studying past biogeochemical cycling in the paleoceanographic record. Empirical evidence suggests that natural fluctuations in the δ15N of surface nutrient N are reflected in the δ15N of exported planktonic biomass and in sedimentary δ15Nbulk. However, δ15Nbulk is an analysis of total combustible sedimentary N, and therefore also includes mixtures of N sources and/or selective removal or preservation of N-containing compounds. Compound-specific nitrogen isotope analyses of individual amino acids (δ15NAA) are novel measurements with the potential to decouple δ15N changes in nutrient N from trophic effects, two main processes that can influence δ15Nbulk records. As a proof of concept study to examine how δ15NAA can be applied in marine sedimentary systems, we compare the δ15NAA signatures of surface and sinking POM sources with shallow surface sediments from the Santa Barbara Basin, a sub-oxic depositional environmental that exhibits excellent preservation of sedimentary organic matter. Our results demonstrate that δ15NAA signatures of both planktonic biomass and sinking POM are well preserved in such surface sediments. However, we also observed an unexpected inverse correlation between δ15N value of phenylalanine (δ15NPhe; the best AA proxy for N isotopic value at the base of the food web) and calculated trophic position. We used a simple N isotope mass balance model to confirm that over long time scales, δ15NPhe values should in fact be directly dependent on shifts in ecosystem trophic position. While this result may appear incongruent with current applications of δ15NAA in food webs, it is consistent with expectations that paleoarchives will integrate N dynamics over much longer timescales. We therefore propose that for paleoceanographic applications, key δ15NAA parameters are ecosystem trophic position, which determines relative partitioning of 15N

  11. Free fatty acids block glucose-induced β-cell proliferation in mice by inducing cell cycle inhibitors p16 and p18.

    PubMed

    Pascoe, Jordan; Hollern, Douglas; Stamateris, Rachel; Abbasi, Munira; Romano, Lia C; Zou, Baobo; O'Donnell, Christopher P; Garcia-Ocana, Adolfo; Alonso, Laura C

    2012-03-01

    Pancreatic β-cell proliferation is infrequent in adult humans and is not increased in type 2 diabetes despite obesity and insulin resistance, suggesting the existence of inhibitory factors. Free fatty acids (FFAs) may influence proliferation. In order to test whether FFAs restrict β-cell proliferation in vivo, mice were intravenously infused with saline, Liposyn II, glucose, or both, continuously for 4 days. Lipid infusion did not alter basal β-cell proliferation, but blocked glucose-stimulated proliferation, without inducing excess β-cell death. In vitro exposure to FFAs inhibited proliferation in both primary mouse β-cells and in rat insulinoma (INS-1) cells, indicating a direct effect on β-cells. Two of the fatty acids present in Liposyn II, linoleic acid and palmitic acid, both reduced proliferation. FFAs did not interfere with cyclin D2 induction or nuclear localization by glucose, but increased expression of inhibitor of cyclin dependent kinase 4 (INK4) family cell cycle inhibitors p16 and p18. Knockdown of either p16 or p18 rescued the antiproliferative effect of FFAs. These data provide evidence for a novel antiproliferative form of β-cell glucolipotoxicity: FFAs restrain glucose-stimulated β-cell proliferation in vivo and in vitro through cell cycle inhibitors p16 and p18. If FFAs reduce proliferation induced by obesity and insulin resistance, targeting this pathway may lead to new treatment approaches to prevent diabetes. PMID:22338094

  12. The Effect of Limited Diffusion and Wet-Dry Cycling on Reversible Polymerization Reactions: Implications for Prebiotic Synthesis of Nucleic Acids.

    PubMed

    Higgs, Paul G

    2016-01-01

    A long-standing problem for the origins of life is that polymerization of many biopolymers, including nucleic acids and peptides, is thermodynamically unfavourable in aqueous solution. If bond making and breaking is reversible, monomers and very short oligomers predominate. Recent experiments have shown that wetting and drying cycles can overcome this problem and drive the formation of longer polymers. In the dry phase, bond formation is favourable, but diffusion is restricted, and bonds only form between monomers that are initially close together. In the wet phase, some of the bonds are hydrolyzed. However, repositioning of the molecules allows new bonds to form in the next dry phase, leading to an increase in mean polymer length. Here, we consider a simple theoretical model that explains the effect of cycling. There is an equilibrium length distribution with a high mean length that could be achieved if diffusion occurred freely in the dry phase. This equilibrium is inaccessible without diffusion. A single dry cycle without diffusion leads to mean lengths much shorter than this. Repeated cycling leads to a significant increase in polymerization relative to a single cycle. In the most favourable case, cycling leads to the same equilibrium length distribution as would be achieved if free diffusion were possible in the dry phase. These results support the RNA World scenario by explaining a potential route to synthesis of long RNAs; however, they also imply that cycling would be beneficial to the synthesis of other kinds of polymers, including peptides, where bond formation involves a condensation reaction. PMID:27338479

  13. The Effect of Limited Diffusion and Wet–Dry Cycling on Reversible Polymerization Reactions: Implications for Prebiotic Synthesis of Nucleic Acids

    PubMed Central

    Higgs, Paul G.

    2016-01-01

    A long-standing problem for the origins of life is that polymerization of many biopolymers, including nucleic acids and peptides, is thermodynamically unfavourable in aqueous solution. If bond making and breaking is reversible, monomers and very short oligomers predominate. Recent experiments have shown that wetting and drying cycles can overcome this problem and drive the formation of longer polymers. In the dry phase, bond formation is favourable, but diffusion is restricted, and bonds only form between monomers that are initially close together. In the wet phase, some of the bonds are hydrolyzed. However, repositioning of the molecules allows new bonds to form in the next dry phase, leading to an increase in mean polymer length. Here, we consider a simple theoretical model that explains the effect of cycling. There is an equilibrium length distribution with a high mean length that could be achieved if diffusion occurred freely in the dry phase. This equilibrium is inaccessible without diffusion. A single dry cycle without diffusion leads to mean lengths much shorter than this. Repeated cycling leads to a significant increase in polymerization relative to a single cycle. In the most favourable case, cycling leads to the same equilibrium length distribution as would be achieved if free diffusion were possible in the dry phase. These results support the RNA World scenario by explaining a potential route to synthesis of long RNAs; however, they also imply that cycling would be beneficial to the synthesis of other kinds of polymers, including peptides, where bond formation involves a condensation reaction. PMID:27338479

  14. Flux control exerted by mitochondrial outer membrane carnitine palmitoyltransferase over beta-oxidation, ketogenesis and tricarboxylic acid cycle activity in hepatocytes isolated from rats in different metabolic states.

    PubMed Central

    Drynan, L; Quant, P A; Zammit, V A

    1996-01-01

    The Flux Control Coefficients of mitochondrial outer membrane carnitine palmitoyltransferase (CPT I) with respect to the overall rates of beta-oxidation, ketogenesis and tricarboxylic acid cycle activity were measured in hepatocytes isolated from rats in different metabolic states (fed, 24 h-starved, starved-refed and starved/insulin-treated). These conditions were chosen because there is controversy as to whether, when significant control ceases to be exerted by CPT I over the rate of fatty oxidation [Moir and Zammit (1994) Trends Biochem. Sci. 19, 313-317], this is transferred to one or more steps proximal to acylcarnitine synthesis (e.g. decreased delivery of fatty acids to the liver) or to the reaction catalysed by mitochondrial 3-hydroxy-3-methyl-glutaryl-CoA synthase [Hegardt (1995) Biochem. Soc. Trans. 23, 486-490]. Therefore isolated hepatocytes were used in the present study to exclude the involvement of changes in the rate of delivery of non-esterified fatty acids (NEFA) to the liver, such as occur in vivo, and to ascertain whether, under conditions of constant supply of NEFA, CPT I retains control over the relevant fluxes of fatty acid oxidation to ketones and carbon dioxide, or whether control is transferred to another (intrahepatocytic) site. The results clearly show that the Flux Control Coefficients of CPT I with respect to overall beta-oxidation and ketogenesis are very high under all conditions investigated, indicating that control is not lost to another intrahepatic site during the metabolic transitions studied. The control of CPT I over tricarboxylic acid cycle activity was always very low. The significance of these findings for the integration of fatty acid and carbohydrate metabolism in the liver is discussed. PMID:8760364

  15. The role of surface chemical analysis in a study to select replacement processes for TCA vapor degreasing

    NASA Technical Reports Server (NTRS)

    Lesley, Michael W.; Davis, Lawrence E.; Moulder, John F.; Carlson, Brad A.

    1995-01-01

    The role of surface-sensitive chemical analysis (ESCA, AES, and SIMS) in a study to select a process to replace 1, 1, 1-trichloroethane (TCA) vapor degreasing as a steel and aluminum bonding surface preparation method is described. The effort was primarily concerned with spray-in-air cleaning processes involving aqueous alkaline and semi-aqueous cleaners and a contamination sensitive epoxy-to-metal bondline. While all five cleaners tested produced bonding strength results equal to or better than those produced by vapor degreasing, the aqueous alkaline cleaners yielded results which were superior to those produced by the semi-aqueous cleaners. The main reason for the enhanced performance appears to be a silicate layer left behind by the aqueous alkaline cleaners. The silicate layer increases the polarity of the surface and enhances epoxy-to-metal bonding. On the other hand, one of the semi-aqueous cleaners left a nonpolar carbonaceous residue which appeared to have a negative effect on epoxy-to-metal bonding. Differences in cleaning efficiency between cleaners/processes were also identified. These differences in surface chemistry, which were sufficient to affect bonding, were not detected by conventional chemical analysis techniques.

  16. The CMS fast beams condition monitor back-end electronics based on MicroTCA technology: status and development

    NASA Astrophysics Data System (ADS)

    Zagozdzinska, Agnieszka A.; Dabrowski, Anne E.; Pozniak, Krzysztof T.

    2015-09-01

    The Fast Beams Condition Monitor (BCM1F), upgraded for LHC Run II, is used to measure the online luminosity and machine induced background for the CMS experiment. The detector consists of 24 single-crystal CVD diamond sensors that are read out with a custom fast front-end chip fabricated in 130 nm CMOS technology. Since the signals from the sensors are used for real time monitoring of the LHC conditions they are processed by dedicated back-end electronics to measure separately rates corresponding to LHC collision products, machine induced background and residual activation exploiting different arrival times. The system is built in MicroTCA technology and uses high speed analog-to-digital converters. In operational modes of high rates, consecutive events, spaced in time by less than 12.5 ns, may cause partially overlapping events. Hence, novel signal processing techniques are deployed to resolve overlapping peaks. The high accuracy qualification of the signals is crucial to determine the luminosity and the machine induced background rates for the CMS experiment and the LHC.

  17. Effects of phosphoenolpyruvate carboxylase desensitization on glutamic acid production in Corynebacterium glutamicum ATCC 13032.

    PubMed

    Wada, Masaru; Sawada, Kazunori; Ogura, Kotaro; Shimono, Yuta; Hagiwara, Takuya; Sugimoto, Masakazu; Onuki, Akiko; Yokota, Atsushi

    2016-02-01

    Phosphoenolpyruvate carboxylase (PEPC) in Corynebacterium glutamicum ATCC13032, a glutamic-acid producing actinobacterium, is subject to feedback inhibition by metabolic intermediates such as aspartic acid and 2-oxoglutaric acid, which implies the importance of PEPC in replenishing oxaloacetic acid into the TCA cycle. Here, we investigated the effects of feedback-insensitive PEPC on glutamic acid production. A single amino-acid substitution in PEPC, D299N, was found to relieve the feedback control by aspartic acid, but not by 2-oxoglutaric acid. A simple mutant, strain R1, having the D299N substitution in PEPC was constructed from ATCC 13032 using the double-crossover chromosome replacement technique. Strain R1 produced glutamic acid at a concentration of 31.0 g/L from 100 g/L glucose in a jar fermentor culture under biotin-limited conditions, which was significantly higher than that of the parent, 26.0 g/L (1.19-fold), indicative of the positive effect of desensitized PEPC on glutamic acid production. Another mutant, strain DR1, having both desensitized PEPC and PYK-gene deleted mutations, was constructed in a similar manner using strain D1 with a PYK-gene deleted mutation as the parent. This mutation had been shown to enhance glutamic acid production in our previous study. Although marginal, strain D1 produced higher glutamic acid, 28.8 g/L, than ATCC13032 (1.11-fold). In contrast, glutamic acid production by strain DR-1 was elevated up to 36.9 g/L, which was 1.42-fold higher than ATCC13032 and significantly higher than the other three strains. The results showed a synergistic effect of these two mutations on glutamic acid production in C. glutamicum. PMID:26168906

  18. Continuous Taurocholic Acid Exposure Promotes Esophageal Squamous Cell Carcinoma Progression Due to Reduced Cell Loss Resulting from Enhanced Vascular Development

    PubMed Central

    Sato, Sho; Yamamoto, Hiroto; Mukaisho, Ken-ichi; Saito, Shota; Hattori, Takanori; Yamamoto, Gaku; Sugihara, Hiroyuki

    2014-01-01

    Background Refluxogenic effects of smoking and alcohol abuse may be related to the risk of esophageal squamous cell carcinoma (ESCC). The present study attempts to clarify the effects of continuous taurocholic acid (TCA) exposure, which is neither mutagenic nor genotoxic, on ESCC progression. Methods A squamous carcinoma cell line (ESCC-DR) was established from a tumor induced in a rat model of gastroduodenal reflux. ESCC-DR cells were incubated with 2 mM TCA for ≥2 months. The effects of continuous TCA exposure were evaluated in vitro on cell morphology, growth, and invasion and in vivo on xenograft tumor growth in nude mice. Moreover, the mean level of secreted transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF) proteins in cell culture supernatants and mRNA synthesis of TGF-β1 and VEGF-A of ESCC cells were measured. The angiogenic potential was further examined by a migration assay using human umbilical vein endothelial cells (HUVECs). Results Continuous TCA exposure induced marked formation of filopodia in vitro. Expression levels of angiogenic factors were significantly higher in the cells treated with TCA than in control cells. Tumor xenografts derived from cells pre-exposed to TCA were larger and more vascularized than those derived from control cells. In addition, TCA exposure increased HUVEC migration. Conclusion Continuous TCA exposure enhanced ESCC progression due to reduced cell loss in vivo. Cell loss was inhibited by TCA-induced vascular endothelial cell migration, which was mediated by TGF-β1 and VEGF-A released from ESCC cells. PMID:24551170

  19. Soil-based cycling and differential uptake of amino acids by three species of strawberry (Fragaria spp.) plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evidence is growing that amino acids can be an important source of plant N in nutrient limited natural ecosystems, but relatively little is known about the effect of agricultural management on soil amino acid pools and turnover. In order to determine the relative effects of soil type and management ...

  20. Nitric oxide participates in the regulation of the ascorbate-glutathione cycle by exogenous jasmonic acid in the leaves of wheat seedlings under drought stress.

    PubMed

    Shan, Changjuan; Zhou, Yan; Liu, Mingjiu

    2015-09-01

    In this paper, we investigated whether nitric oxide (NO) participated in the regulation of the ascorbate-glutathione (AsA-GSH) cycle by exogenous jasmonic acid (JA) in the leaves of wheat seedlings under drought stress. The findings of our study showed that drought stress significantly enhanced the AsA-GSH cycle by upregulating the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR). Drought stress also markedly increased electrolyte leakage (EL), malondialdehyde (MDA) content, NO content, and significantly reduced the ratios of reduced ascorbate/dehydroascorbic acid (AsA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG) compared with control. Exogenous JA significantly increased the above indicators, compared with drought stress alone. All these effects of JA were inhibited by pretreatment with NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Meanwhile, exogenous JA markedly decreased MDA content and electrolyte leakage of wheat leaves under drought stress. Pretreatment with cPTIO reversed the above effects of exogenous JA. Our findings indicated that NO induced by exogenous JA upregulated the activity of the AsA-GSH cycle and had important role in drought tolerance. PMID:25577230

  1. An Oral Load of [13C3]Glycerol and Blood NMR Analysis Detect Fatty Acid Esterification, Pentose Phosphate Pathway, and Glycerol Metabolism through the Tricarboxylic Acid Cycle in Human Liver.

    PubMed

    Jin, Eunsook S; Sherry, A Dean; Malloy, Craig R

    2016-09-01

    Drugs and other interventions for high impact hepatic diseases often target biochemical pathways such as gluconeogenesis, lipogenesis, or the metabolic response to oxidative stress. However, traditional liver function tests do not provide quantitative data about these pathways. In this study, we developed a simple method to evaluate these processes by NMR analysis of plasma metabolites. Healthy subjects ingested [U-(13)C3]glycerol, and blood was drawn at multiple times. Each subject completed three visits under differing nutritional states. High resolution (13)C NMR spectra of plasma triacylglycerols and glucose provided new insights into a number of hepatic processes including fatty acid esterification, the pentose phosphate pathway, and gluconeogenesis through the tricarboxylic acid cycle. Fasting stimulated pentose phosphate pathway activity and metabolism of [U-(13)C3]glycerol in the tricarboxylic acid cycle prior to gluconeogenesis or glyceroneogenesis. Fatty acid esterification was transient in the fasted state but continuous under fed conditions. We conclude that a simple NMR analysis of blood metabolites provides an important biomarker of pentose phosphate pathway activity, triacylglycerol synthesis, and flux through anaplerotic pathways in mitochondria of human liver. PMID:27432878

  2. Effects of valproic acid and pioglitazone on cell cycle progression and proliferation of T-cell acute lymphoblastic leukemia Jurkat cells

    PubMed Central

    Jazi, Marie Saghaeian; Mohammadi, Saeed; Yazdani, Yaghoub; Sedighi, Sima; Memarian, Ali; Aghaei, Mehrdad

    2016-01-01

    Objective(s): T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignant tumor. Administration of chemical compounds influencing apoptosis and T cell development has been discussed as promising novel therapeutic strategies. Valproic acid (VPA) as a recently emerged anti-neoplastic histone deacetylase (HDAC) inhibitor and pioglitazone (PGZ) as a high-affinity peroxisome proliferator-activated receptor-gamma (PPARγ) agonist have been shown to induce apoptosis and cell cycle arrest in different studies. Here, we aimed to investigate the underlying molecular mechanisms involved in anti-proliferative effects of these compounds on human Jurkat cells. Materials and Methods: Treated cells were evaluated for cell cycle progression and apoptosis using flowcytometry and MTT viability assay. Real-time RT-PCR was carried out to measure the alterations in key genes associated with cell death and cell cycle arrest. Results: Our findings illustrated that both VPA and PGZ can inhibit Jurkat E6.1 cells in vitro after 24 hr; however, PGZ 400 μM presents the most anti-proliferative effect. Interestingly, treated cells have been arrested in G2/M with deregulated cell division cycle 25A (Cdc25A) phosphatase and cyclin-dependent kinase inhibitor 1B (CDKN1B or p27) expression. Expression of cyclin D1 gene was inhibited when DNA synthesis entry was declined. Cell cycle deregulation in PGZ and VPA-exposed cells generated an increase in the proportion of aneuploid cell population, which has not reported before. Conclusion: These findings define that anti-proliferative effects of PGZ and VPA on Jurkat cell line are mediated by cell cycle deregulation. Thus, we suggest PGZ and VPA may relieve potential therapeutic application against apoptosis-resistant malignancies.

  3. Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles

    PubMed Central

    Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

    2014-01-01

    Objective: To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). Materials and Methods: The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. Results: There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. Conclusion: It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness. PMID:25512737

  4. Dietary Fatty Acids from Leaves of Clerodendrum Volubile Induce Cell Cycle Arrest, Downregulate Matrix Metalloproteinase-9 Expression, and Modulate Redox Status in Human Breast Cancer.

    PubMed

    Erukainure, Ochuko L; Zaruwa, Moses Z; Choudhary, M Iqbal; Naqvi, S Asma; Ashraf, Nadia; Hafizur, Rahman M; Muhammad, Aliyu; Ebuehi, Osaretin A T; Elemo, Gloria N

    2016-01-01

    The antiproliferative effect of the fatty acid components of Clerodendrum volubile leaves as well as its antioxidant effect on MCF-7 and MDA-MB-231 human breast cancer cell lines were investigated. Fatty acids extracted from C. volubile leaf oil were subjected to gas chromatography mass spectrometry (GCMS) analysis. The cells were cultured and treated with the fatty acids for 48 h, after which the antiproliferation effect was ascertained via MTT assay and cell viability analysis using BD fluorescence activated cells sorting (FACS) Calibur. Cell cycle was analyzed by flow cytometry on FACS Calibur. Western blotting was used in determining expression of proteins in the cell lines. The treated cell lines were assessed for reduced glutathione level, catalase, superoxide dismutase, and lipid peroxidation. The fatty acids significantly inhibited cell proliferation, arrested G0/G1 phase, downregulated the expression of MMP-9, and attenuated oxidative stress in of MCF-7 cell lines but had little or no effect on MDA-MB-231 cell lines. These results indicate the therapeutic potential of the fatty acids components of the leaves of C. volubile on human breast cancer, which may be explored further in drug development. PMID:27043182

  5. Amino acid cycling in the Mississippi River Plume and effects from the passage of Hurricanes Isadore and Lili

    NASA Astrophysics Data System (ADS)

    Bianchi, Thomas S.; Grace, Bryan L.; Carman, Kevin R.; Maulana, Ivan

    2014-08-01

    We present data on the effects of Hurricanes Isadore and Lili on the spatial and temporal variations in concentrations of amino acids, and other bulk dissolved and particulate constituents in surface waters of the Mississippi River Plume (MRP) collected during 3 survey cruises (March 2002, October 2002, and April 2004). Abiotic factors (e.g., particle sorption and sediment resuspension) had the largest contribution in describing DAA and PAA dynamics in the MRP. The range of dissolved organic carbon (DOC) (88.61 to 699.90 μM) and particulate organic carbon (POC) (0.08 to 32.72 μM) values was slightly higher than the range observed for a broader region of the Louisiana shelf, but in general agreed with peak values at the mid-salinity range of the plume. The positive and negative correlations between acidic (e.g., aspartic acid and glutamic acid) and basic (e.g., histidine and arginine) DAA and salinity, respectively, in the MRP, were largely controlled by differential partitioning of amino acids with suspended sediments. Concentrations of β-alanine, γ-aminobutyric acid, and δ-aminovaleric acid were significantly higher during October 2002 compared to spring sampling events, due to resuspension of shelf sediments caused by the recent passage of Hurricane Isadore and the approach of Hurricane Lili, as it entered the Gulf of Mexico during our sampling.

  6. Evidence for a Relationship Between Equine Abortion (Herpes) Virus Deoxyribonucleic Acid Synthesis and the S Phase of the KB Cell Mitotic Cycle

    PubMed Central

    Lawrence, William C.

    1971-01-01

    Autoradiographic analyses of deoxyribonucleic acid (DNA) synthesis in randomly growing KB cell cultures infected with equine abortion virus (EAV) suggested that viral DNA synthesis was initiated only at times that coincided with the entry of noninfected control cells into the S phase of the cell cycle. Synchronized cultures of KB cells were infected at different stages of the cell cycle, and rates of synthesis of cellular and viral DNA were measured. When cells were infected at different times within the S phase, viral DNA synthesis was initiated 2 to 3 hr after infection. However, when cells in G1 and G2 were infected, the initiation of viral DNA synthesis was delayed and occurred only at times corresponding to the S phase. The times when viral DNA synthesis began were independent of the time of infection and differed by as much as 5 hr, depending on the stage of the cell cycle at which cells were infected. Viral one-step growth curves were also related to the S phase in a manner which indicated a relationship between the initiation of viral DNA synthesis and the S phase. These data support the concept that initiation of EAV DNA synthesis is dependent upon some cellular function(s) which is related to the S phase of the cell cycle. PMID:4254680

  7. Input of trichloroacetic acid into the vegetation of various climate zones--measurements on several continents.

    PubMed

    Weissflog, Ludwig; Krüger, Gert; Elansky, Nikolai; Putz, Erich; Pfennigsdorff, Andrea; Seyfarth, Klaus Ullrich; Nüchter, Matthias; Lange, Christian; Kotte, Karsten

    2003-07-01

    Trichloroacetic acid (TCA, CCl(3)COOH) is a phytotoxic chemical. Although TCA salts and derivates were once used as herbicides to combat perennial grasses and weeds, they have since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, the high-volatile C(2)-chlorohydrocarbons tetrachloroethene (TECE, C(2)Cl(4)) and 1,1,1-trichloroethane (TCE, CCl(3)CH(3)) can react under oxidative conditions in the atmosphere to form TCA and other substances. The ongoing industrialisation of Southeast Asia, South Africa and South America means that use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere can be expected to rise. The increasing emissions of this substance--together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the southern hemisphere--could lead to a greater input/formation of TCA in the vegetation located in the lee of these emission sources. By means of biomonitoring studies, the input/formation of TCA in vegetation was detected at various locations in South America, North America, Africa, and Europe. PMID:12738268

  8. A CRADLE TO GATE LIFE CYCLE ANALYSIS OF THE BIOPOLYMER POLYLACTIC ACID: LOOKING BEYOND GLOBAL WARMING AND FOSSIL FUEL USE

    EPA Science Inventory

    Derived from corn, the biopolymer polylactic acid (PLA) has recently emerged in the marketplace and is advertised as a sustainable alternative to petroleum-based polymers. Research into the environmental implications of biobased production has focused primarily on global warming...

  9. Reversible effect of all-trans-retinoic acid on AML12 hepatocyte proliferation and cell cycle progression

    EPA Science Inventory

    The role of all-trans-retinoic acid (atRA) in the regulation of cellular proliferation and differentiation is well documented. Numerous studies have established the cancer preventive propertiesofatRAwhichfunctionstoregulate levels ofcellcycleproteinsessentialfortheGliS transition...

  10. Tranexamic Acid

    MedlinePlus

    ... is used to treat heavy bleeding during the menstrual cycle (monthly periods) in women. Tranexamic acid is in ... tablets for more than 5 days in a menstrual cycle or take more than 6 tablets in a ...

  11. Diel leaf growth cycles in Clusia spp. are related to changes between C3 photosynthesis and crassulacean acid metabolism during development and during water stress.

    PubMed

    Walter, Achim; Christ, Maja M; Rascher, Uwe; Schurr, Ulrich; Osmond, Barry

    2008-04-01

    This study reports evidence that the timing of leaf growth responds to developmental and environmental constraints in Clusia spp. We monitored diel patterns of leaf growth in the facultative C(3)-crassulacean acid metabolism (CAM) species Clusia minor and in the supposedly obligate CAM species Clusia alata using imaging methods and followed diel patterns of CO2 exchange and acidification. Developing leaves of well-watered C. minor showed a C3-like diel pattern of gas exchange and growth, with maximum relative growth rate (RGR) in the early night period. Growth slowed when water was withheld, accompanied by nocturnal CO2 exchange and the diel acid change characteristic of CAM. Maximum leaf RGR shifted from early night to early in the day when water was withheld. In well-watered C. alata, similar changes in the diel pattern of leaf growth occurred with the development of CAM during leaf ontogeny. We hypothesize that the shift in leaf growth cycle that accompanies the switch from C3 photosynthesis to CAM is mainly caused by the primary demand of CAM for substrates for nocturnal CO2 fixation and acid synthesis, thus reducing the availability of carbohydrates for leaf growth at night. Although the shift to leaf growth early in the light is presumably associated with the availability of carbohydrates, source-sink relationships and sustained diurnal acid levels in young leaves of Clusia spp. need further evaluation in relation to growth processes. PMID:18182020

  12. TREATOGENIC ACTIVITY OF TRICHOLORACETIC ACID IN THE RATE

    EPA Science Inventory

    Trichloroacetic acid (TCA) is a by-product of the chlorine disinfection of water containing natural organic material. t is detectable in finished drinking water at levels comparable to the trihalomethanes (930-160 ug/L). CA is also formed in vivo after ingestion of hypochelorite ...

  13. Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb's cycle flux independent of ATP synthesis.

    PubMed

    Cline, Gary W; Pongratz, Rebecca L; Zhao, Xiaojian; Papas, Klearchos K

    2011-11-11

    Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with (31)P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by (13)C NMR isotopomer analysis of the fate of [U-(13)C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found to be similar in DMEM to those in KRB. And, the correlation of total PC flux with insulin secretion rates in DMEM was found to be congruous with the correlation in KRB. Together, these results suggest that signaling mechanisms associated with both TCA cycle flux and with anaplerotic flux, but not ATP production, may be responsible for the enhanced rates of insulin secretion in more complex, and physiologically-relevant media. PMID:22008547

  14. SUBCHRONIC 90-DAY TOXICITY OF DICHLOROACETIC AND TRICHLORACETIC ACID IN RATS

    EPA Science Inventory

    Male Sprague-Dawley rats were treated with either dichloroacetic acid (DCA) or trichloroacetic acid (TCA) in the drinking water at levels of 0, 50, 500 and 5000 ppm for a period of 90 days to determine the toxicities associated with subchronic exposure. ll animals were sacrificed...

  15. USE OF THE COMPOSITION AND STABLE CARBON ISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING

    EPA Science Inventory

    We use measurements of the concentration and stable carbon isotopic ratio (Gamma 13C) of individual microbial phospholipid fatty acids (PLFAS) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SO...

  16. Investigation of the Effects of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) on Apoptosis and Cell Cycle in a Zebrafish (Danio rerio) Liver Cell Line

    PubMed Central

    Cui, Yuan; Liu, Wei; Xie, Wenping; Yu, Wenlian; Wang, Cheng; Chen, Huiming

    2015-01-01

    This study aimed to explore the effects of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) on apoptosis and cell cycle in a zebrafish (Danio rerio) liver cell line (ZFL). Treatment groups included a control group, PFOA-IC50, PFOA-IC80, PFOS-IC50 and PFOS-IC80 groups. IC50 and IC80 concentrations were identified by cellular modeling and MTT assays. mRNA levels of p53, Bcl-2, Bax, Caspase-3 and NF-κB p65 were detected by qPCR. Cell apoptosis and cell cycle were detected by flow cytometry and the protein levels of p53, Bcl-2, Bax, Caspase-3 and NF-κB p65 were determined by western blotting. Both PFOA and PFOS inhibited the growth of zebrafish liver cells, and the inhibition rate of PFOS was higher than that of PFOA. Bcl-2 expression levels in the four groups were significantly higher than the control group and Bcl-2 increased significantly in the PFOA-IC80 group. However, the expression levels of Bax in the four treatment groups were higher than the control group. The percentage of cell apoptosis increased significantly with the treatment of PFOA and PFOS (p < 0.05). Cell cycle and cell proliferation were blocked in both the PFOA-IC80 and PFOS-IC80 groups, indicating that PFOA-IC80 and PFOS-IC50 enhanced apoptosis in ZFL cells. PMID:26690195

  17. During hormone depletion or tamoxifen treatment of breast cancer cells the estrogen receptor apoprotein supports cell cycling through the retinoic acid receptor α1 apoprotein

    PubMed Central

    2011-01-01

    Introduction Current hormonal adjuvant therapies for breast cancer including tamoxifen treatment and estrogen depletion are overall tumoristatic and are severely limited by the frequent recurrence of the tumors. Regardless of the resistance mechanism, development and progression of the resistant tumors requires the persistence of a basal level of cycling cells during the treatment for which the underlying causes are unclear. Methods In estrogen-sensitive breast cancer cells the effects of hormone depletion and treatment with estrogen, tamoxifen, all-trans retinoic acid (ATRA), fulvestrant, estrogen receptor α (ER) siRNA or retinoic acid receptor α (RARα) siRNA were studied by examining cell growth and cycling, apoptosis, various mRNA and protein expression levels, mRNA profiles and known chromatin associations of RAR. RARα subtype expression was also examined in breast cancer cell lines and tumors by competitive PCR. Results Basal proliferation persisted in estrogen-sensitive breast cancer cells grown in hormone depleted conditioned media without or with 4-hydroxytamoxifen (OH-Tam). Downregulating ER using either siRNA or fulvestrant inhibited basal proliferation by promoting cell cycle arrest, without enrichment for ErbB2/3+ overexpressing cells. The basal expression of RARα1, the only RARα isoform that was expressed in breast cancer cell lines and in most breast tumors, was supported by apo-ER but was unaffected by OH-Tam; RAR-β and -γ were not regulated by apo-ER. Depleting basal RARα1 reproduced the antiproliferative effect of depleting ER whereas its restoration in the ER depleted cells partially rescued the basal cycling. The overlapping tamoxifen-insensitive gene regulation by apo-ER and apo-RARα1 comprised activation of mainly genes promoting cell cycle and mitosis and suppression of genes involved in growth inhibition; these target genes were generally insensitive to ATRA but were enriched in RAR binding sites in associated chromatin regions

  18. Comparison of efficacy of chemical peeling with 25% trichloroacetic acid and 0.1% retinoic acid for facial rejuvenation

    PubMed Central

    Gurel, Mehmet Salih; Gungor, Sule; Tekeli, Omur; Canat, Dilek

    2016-01-01

    Introduction Skin aging is a problem which negatively affects the psyche of the person, social relations, as well as work life and health and which compels the patients to find appropriate treatment methods. Numerous treatment methods have been developed in order to delay aging and to reduce the aging effects in addition to having a younger, healthier and more beautiful facial appearance. Aim To compare the efficiency, cosmetic results and possible adverse effects of the peeling treatment with 25% trichloroacetic acid (TCA) and 0.1% retinoic acid for facial rejuvenation in patients presenting with skin aging. Material and methods Fifty female patients in total presenting with medium and advanced degree skin aging were subject to this study. Two separate treatment groups were formed; the first group underwent chemical skin treatment with 25% TCA while the other group was applied with 0.1% retinoic acid treatment. Following the 4 months’ treatment the patients were controlled three times in total for post lesional hypopigmentation, hyperpigmentation, scars, skin irritation and other possible changes per month. The pretreatment and first follow-up visit, and final control images were comparatively evaluated by three observers via specific software. Results The healing rates of the group subject to retinoic acid were statistically higher (p < 0.05) compared to patients in the TCA group in the final follow-up visit following the treatment according to the first and second observers. On the other hand, according to the third observer, patients applied with retinoic acid presented with higher healing rates compared to those treated with TCA, however; this rate was not statistically significant (p > 0.05). The frequency of TCA- and retinoic acid-associated adverse effects was similar in both groups (p > 0.05). As a result of both treatments, a reduction in the quality of life scores as well as a pronounced recovery (p = 0.001) in the quality of life of those patients

  19. Transcriptome analysis highlights changes in the leaves of maize plants cultivated in acidic soil containing toxic levels of Al(3+).

    PubMed

    Mattiello, Lucia; Begcy, Kevin; da Silva, Felipe Rodrigues; Jorge, Renato A; Menossi, Marcelo

    2014-12-01

    Soil acidity limits crop yields worldwide and is a common result of aluminum (Al) phytotoxicity, which is known to inhibit root growth. Here, we compared the transcriptome of leaves from maize seedlings grown under control conditions (soil without free Al) and under acidic soil containing toxic levels of Al. This study reports, for the first time, the complex transcriptional changes that occur in the leaves of maize plants grown in acidic soil with phytotoxic levels of Al. Our data indicate that 668 genes were differentially expressed in the leaves of plants grown in acidic soil, which is significantly greater than that observed in our previous work with roots. Genes encoding TCA cycle enzymes were upregulated, although no specific transporter of organic acids was differentially expressed in leaves. We also provide evidence for positive roles for auxin and brassinosteroids in Al tolerance, whereas gibberellin and jasmonate may have negative roles. Our data indicate that plant responses to acidic soil with high Al content are not restricted to the root; tolerance mechanisms are also displayed in the aerial parts of the plant, thus indicating that the entire plant responds to stress. PMID:25205121

  20. Changes in urinary amino acids excretion in relationship with muscle activity markers over a professional cycling stage race: in search of fatigue markers.

    PubMed

    Corsetti, Roberto; Barassi, Alessandra; Perego, Silvia; Sansoni, Veronica; Rossi, Alessandra; Damele, Clara Anna Linda; Melzi D'Eril, Gianlodovico; Banfi, Giuseppe; Lombardi, Giovanni

    2016-01-01

    The aim of this study was to identify the relationship between metabolic effort, muscular damage/activity indices, and urinary amino acids profile over the course of a strenuous prolonged endurance activity, as a cycling stage race is, in order to identify possible fatigue markers. Nine professional cyclists belonging to a single team, competing in the Giro d'Italia cycling stage race, were anthropometrically characterized and sampled for blood and urine the day before the race started, and on days 12 and 23 of the race. Diet was kept the same over the race, and power output and energy expenditure were recorded. Sera were assayed for muscle markers (lactate dehydrogenase, aspartate aminotransferase, and creatine kinase activities, and blood urea nitrogen), and creatinine, all corrected for plasma volume changes. Urines were profiled for amino acid concentrations, normalized on creatinine excretion. Renal function, in terms of glomerular filtration rate, was monitored by MDRD equation corrected on body surface area. Creatine kinase activity and blood urea were increased during the race as did serum creatinine while kidney function remained stable. Among the amino acids, taurine, glycine, cysteine, leucine, carnosine, 1-methyl histidine, and 3-methyl histidine showed a net decreased, while homocysteine was increased. Taurine and the dipeptide carnosine (β-alanyl-L-histidine) were significantly correlated with the muscle activity markers and the indices of effort. In conclusion, the metabolic profile is modified strikingly due to the effort. Urinary taurine and carnosine seem useful tools to evaluate the muscle damage and possibly the fatigue status on a long-term basis. PMID:26306846

  1. Development of an electrode for lead-acid batteries possessing a high electrochemical utilization factor and invariable cycling characteristics

    NASA Astrophysics Data System (ADS)

    Yolshina, L. A.; Kudyakov, V. Ya.; Zyryanov, V. G.

    Investigations have been carried out on the deposition of compact lead layers on the surfaces of various metallic substrates. It is shown that the lead coatings so obtained are non-uniform in thickness and feature high porosities. The lead-film electrode thus produced on the surface of a fine copper grid can be used as a positive electrode in the lead-acid battery.

  2. Acid rock drainage and rock weathering in Antarctica: important sources for iron cycling in the Southern Ocean.

    PubMed

    Dold, B; Gonzalez-Toril, E; Aguilera, A; Lopez-Pamo, E; Cisternas, M E; Bucchi, F; Amils, R

    2013-06-18

    Here we describe biogeochemical processes that lead to the generation of acid rock drainage (ARD) and rock weathering on the Antarctic landmass and describe why they are important sources of iron into the Antarctic Ocean. During three expeditions, 2009-2011, we examined three sites on the South Shetland Islands in Antarctica. Two of them displayed intensive sulfide mineralization and generated acidic (pH 3.2-4.5), iron-rich drainage waters (up to 1.78 mM Fe), which infiltrated as groundwater (as Fe(2+)) and as superficial runoff (as Fe(3+)) into the sea, the latter with the formation of schwertmannite in the sea-ice. The formation of ARD in the Antarctic was catalyzed by acid mine drainage microorganisms found in cold climates, including Acidithiobacillus ferrivorans and Thiobacillus plumbophilus. The dissolved iron (DFe) flux from rock weathering (nonmineralized control site) was calculated to be 0.45 × 10(9) g DFe yr(-1) for the nowadays 5468 km of ice-free Antarctic rock coastline which is of the same order of magnitude as glacial or aeolian input to the Southern Ocean. Additionally, the two ARD sites alone liberate 0.026 and 0.057 × 10(9) g DFe yr(-1) as point sources to the sea. The increased iron input correlates with increased phytoplankton production close to the source. This might even be enhanced in the future by a global warming scenario, and could be a process counterbalancing global warming. PMID:23682976

  3. Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling

    PubMed Central

    Malik, Ashish A.; Dannert, Helena; Griffiths, Robert I.; Thomson, Bruce C.; Gleixner, Gerd

    2015-01-01

    Using a pulse chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of rhizosphere soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h) and DNA (30 h) turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 days), while phospholipid fatty acids (PLFAs) had the slowest turnover (42 days). PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings. PMID:25914679

  4. Abscisic Acid Participates in the Control of Cell Cycle Initiation Through Heme Homeostasis in the Unicellular Red Alga Cyanidioschyzon merolae.

    PubMed

    Kobayashi, Yuki; Ando, Hiroyuki; Hanaoka, Mitsumasa; Tanaka, Kan

    2016-05-01

    ABA is a phytohormone that is synthesized in response to abiotic stresses and other environmental changes, inducing various physiological responses. While ABA has been found in unicellular photosynthetic organisms, such as cyanobacteria and eukaryotic algae, its function in these organisms is poorly understood. Here, we found that ABA accumulated in the unicellular red alga Cyanidioschyzon merolae under conditions of salt stress and that the cell cycle G1/S transition was inhibited when ABA was added to the culture medium. A gene encoding heme-scavenging tryptophan-rich sensory protein-related protein (CmTSPO; CMS231C) was positively regulated by ABA, as in Arabidopsis, and CmTSPO bound heme in vitro. The intracellular content of total heme was increased by addition of ABA, but unfettered heme decreased, presumably due to scavenging by CmTSPO. The inhibition of DNA replication by ABA was negated by addition of heme to the culture medium. Thus, we propose a regulatory role for ABA and heme in algal cell cycle initiation. Finally, we found that a C. merolae mutant that is defective in ABA production was more susceptible to salt stress, indicating the importance of ABA to stress resistance in red algae. PMID:27044672

  5. Subsurface Cycling of Nitrogen and Anaerobic Aromatic Hydrocarbon Biodegradation Revealed by Nucleic Acid and Metabolic Biomarkers▿ †

    PubMed Central

    Yagi, Jane M.; Suflita, Joseph M.; Gieg, Lisa M.; DeRito, Christopher M.; Jeon, Che-Ok; Madsen, Eugene L.

    2010-01-01

    Microbial processes are crucial for ecosystem maintenance, yet documentation of these processes in complex open field sites is challenging. Here we used a multidisciplinary strategy (site geochemistry, laboratory biodegradation assays, and field extraction of molecular biomarkers) to deduce an ongoing linkage between aromatic hydrocarbon biodegradation and nitrogen cycling in a contaminated subsurface site. Three site wells were monitored over a 10-month period, which revealed fluctuating concentrations of nitrate, ammonia, sulfate, sulfide, methane, and other constituents. Biodegradation assays performed under multiple redox conditions indicated that naphthalene metabolism was favored under aerobic conditions. To explore in situ field processes, we measured metabolites of anaerobic naphthalene metabolism and expressed mRNA transcripts selected to document aerobic and anaerobic microbial transformations of ammonia, nitrate, and methylated aromatic contaminants. Gas chromatography-mass spectrometry detection of two carboxylated naphthalene metabolites and transcribed benzylsuccinate synthase, cytochrome c nitrite reductase, and ammonia monooxygenase genes indicated that anaerobic metabolism of aromatic compounds and both dissimilatory nitrate reduction to ammonia (DNRA) and nitrification occurred in situ. These data link formation (via DNRA) and destruction (via nitrification) of ammonia to in situ cycling of nitrogen in this subsurface habitat, where metabolism of aromatic pollutants has led to accumulation of reduced metabolic end products (e.g., ammonia and methane). PMID:20348302

  6. Efficient production of gamma-aminobutyric acid using Escherichia coli by co-localization of glutamate synthase, glutamate decarboxylase, and GABA transporter.

    PubMed

    Dung Pham, Van; Somasundaram, Sivachandiran; Lee, Seung Hwan; Park, Si Jae; Hong, Soon Ho

    2016-01-01

    Gamma-aminobutyric acid (GABA) is an important bio-product, which is used in pharmaceutical formulations, nutritional supplements, and biopolymer monomer. The traditional GABA process involves the decarboxylation of glutamate. However, the direct production of GABA from glucose is a more efficient process. To construct the recombinant strains of Escherichia coli, a novel synthetic scaffold was introduced. By carrying out the co-localization of glutamate synthase, glutamate decarboxylase, and GABA transporter, we redirected the TCA cycle flux to GABA pathway. The genetically engineered E. coli strain produced 1.08 g/L of GABA from 10 g/L of initial glucose. Thus, with the introduction of a synthetic scaffold, we increased GABA production by 2.2-fold. The final GABA concentration was increased by 21.8% by inactivating competing pathways. PMID:26620318

  7. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  8. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    NASA Astrophysics Data System (ADS)

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  9. Selective 13C labeling of nucleotides for large RNA NMR spectroscopy using an E. coli strain disabled in the TCA cycle.

    PubMed

    Thakur, Chandar S; Sama, Jacob N; Jackson, Melantha E; Chen, Bin; Dayie, T Kwaku

    2010-12-01

    Escherichia coli (E. coli) is an ideal organism to tailor-make labeled nucleotides for biophysical studies of RNA. Recently, we showed that adding labeled formate enhanced the isotopic enrichment at protonated carbon sites in nucleotides. In this paper, we show that growth of a mutant E. coli strain DL323 (lacking succinate and malate dehydrogenases) on (13)C-2-glycerol and (13)C-1,3-glycerol enables selective labeling at many useful sites for RNA NMR spectroscopy. For DL323 E. coli grown in (13)C-2-glycerol without labeled formate, all the ribose carbon atoms are labeled except the C3' and C5' carbon positions. Consequently the C1', C2' and C4' positions remain singlet. In addition, only the pyrimidine base C6 atoms are substantially labeled to ~96% whereas the C2 and C8 atoms of purine are labeled to ~5%. Supplementing the growth media with (13)C-formate increases the labeling at C8 to ~88%, but not C2. Not unexpectedly, addition of exogenous formate is unnecessary for attaining the high enrichment levels of ~88% for the C2 and C8 purine positions in a (13)C-1,3-glycerol based growth. Furthermore, the ribose ring is labeled in all but the C4' carbon position, such that the C2' and C3' positions suffer from multiplet splitting but the C5' position remains singlet and the C1' position shows a small amount of residual C1'-C2' coupling. As expected, all the protonated base atoms, except C6, are labeled to ~90%. In addition, labeling with (13)C-1,3-glycerol affords an isolated methylene ribose with high enrichment at the C5' position (~90%) that makes it particularly attractive for NMR applications involving CH(2)-TROSY modules without the need for decoupling the C4' carbon. To simulate the tumbling of large RNA molecules, perdeuterated glycerol was added to a mixture of the four nucleotides, and the methylene TROSY experiment recorded at various temperatures. Even under conditions of slow tumbling, all the expected carbon correlations were observed, which indicates this approach of using nucleotides obtained from DL323 E. coli will be applicable to high molecular weight RNA systems. PMID:21057854

  10. Combined effects of CO2 enrichment and elevated growth temperatures on metabolites in soybean leaflets; evidence for dynamic changes of TCA cycle intermediates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean (Glycine max [Merr.]L.) was grown in indoor chambers with ambient (38 Pa) and elevated (70 Pa) CO2 and day/night temperature treatments of 28/20, 32/24, and 36/28 °C. Net rates of CO2 assimilation increased with growth temperature and were enhanced an additional 25% on average by CO2 enrich...

  11. Efficacy of 15% Trichloroacetic Acid and 50% Glycolic Acid Peel in the Treatment of Frictional Melanosis: A Comparative Study

    PubMed Central

    Sacchidanand, S; Shetty, Ashvith B; Leelavathy, B

    2015-01-01

    Background: Frictional dermal melanosis is aesthetically displeasing. Various modalities ranging from depigmenting agents to lasers have been tried but it continues to be a difficult problem to treat. Objective: To study and compare the efficacy of 15% trichloroacetic acid (TCA) and 50% glycolic acid in the treatment of frictional melanosis of the forearm. Materials and Methods: 40 patients of frictional melanosis of the forearm were included in the study. Patients were randomly divided into two equal groups A and B. Pre-peel priming was carried out with 12% glycolic acid and sunscreen for 2 weeks. Group A was treated with trichloroacetic acid (TCA-15%) peel and Group B with glycolic acid (GA-50%) peel. Four peels were done one every 15 days. Clinical photographs were taken to assess the response. Response to therapy was evaluated by both objective and subjective methods. The patients were followed up for 3 months after the last peel to note any relapse. Results: Both TCA and glycolic acid peels were effective in frictional melanosis. TCA showed better response compared to glycolic acid at the end of the treatment, both by subjective and objective methods. However, this difference was not statistically significant (P > 0.05). No permanent side effects were seen in any of the treated patients and the improvement was sustained without any relapse at 3 months. Conclusion: Chemical peeling with both tricholoroacetic acid (15%) and glycolic acid (50%) is safe and effective for the treatment of frictional dermal melanosis. Tricholoroacetic acid was found to be marginally superior to glycolic acid. PMID:25949021

  12. Temporal variation in the distribution of hyaluronic acid, CD44s, and CD44v6 in the human endometrium across the menstrual cycle.

    PubMed

    Afify, Alaa M; Craig, Sarah; Paulino, Augusto F G

    2006-09-01

    Tissues undergoing rapid growth and regeneration contain hyaluronic acid (HA) as a prominent component of the extracellular matrix. The physiologic role of HA is partly mediated by its relationship with CD44, its major cell surface receptor. Given the extensive remodeling of the endometrium during the menstrual cycle, the authors sought to determine whether these changes are related to the levels of HA, CD44s, and CD44v6 in the endometrium. Archival paraffin embedded cell blocks from 10 cases of proliferative endometrium and 20 cases of secretory endometrium were retrieved from the surgical pathology files. Specimens from the secretory phase were subdivided into three categories: early secretory (day 15-18), mid-secretory (day 19-23), and late secretory (day 24-28). All cases were stained for hyaluronic acid, CD44s, and CD44v6. Sections from umbilical cord, tonsil, and squamous cell carcinoma served as positive controls for HA, CD44s, and CD44v6, respectively. Positive staining was defined as droplet to diffuse intracytoplasmic or extracellular staining for HA and uniform membranous staining for CD44. During the proliferative phase, the endometrial glands and the stroma were both negative for CD44s and CD44v6 in all cases. In the secretory phase, the endometrial glands were negative for CD44s in all cases, but CD44v6 was expressed in 12 (60%) of cases. In contrast, the stromal cells expressed CD44s in 18 (90%) cases and were negative for CD44v6 in all cases. HA staining was present in the endometrial stroma throughout the menstrual cycle but was most intense (3+) and diffuse during the midsecretory phase. There was perivascular staining for HA throughout the cycle; it was most intense adjacent to the spiral arterioles in the secretory phase. These data indicate temporal and geographic differences in HA and CD44 staining in the endometrium in concert with the menstrual cycle. The timing of peak staining of HA and CD44s in the stroma and the upregulation of CD44v6 in

  13. Mathematical analysis of isotope labeling in the citric acid cycle with applications to 13C NMR studies in perfused rat hearts.

    PubMed

    Chance, E M; Seeholzer, S H; Kobayashi, K; Williamson, J R

    1983-11-25

    Rat hearts have been perfused in vitro with 5 mM glucose and either 5 mM acetate or 1 mM pyruvate to achieve steady state conditions, followed by replacement of the acetate with 90% enriched [2-13C]acetate or pyruvate with 90% enriched [3-13C]pyruvate. The hearts were frozen different times after addition of 13C-substrate and neutralized perchloric acid extracts from three pooled hearts per time point were used to obtain high resolution proton-decoupled 13C NMR spectra at 90.55 MHz. The 13C fractional enrichment of individual carbons of different metabolites was calculated from the area of the resolved resonances after correction for nuclear Overhauser enhancement and saturation effects. A mathematical flux model of the citric acid cycle and ancillary transamination reactions was constructed with the FACSIMILE program, and used to solve unknown flux parameters with constant pool sizes by nonlinear least squares analysis of the approximately 200 simultaneous differential equations required to describe the reactions. With [2-13C] acetate as substrate, resonances and line splittings due to 13C-13C spin coupling of the C-2, C-3, and C-4 carbons of glutamate were well resolved. The half-times to reach maximum 13C enrichment were 2.6 min for glutamate C-4 and 8 min for glutamate C-2 and C-3. From these data, a well determined citric acid cycle flux of 8.3 mumol/g dry weight X min was calculated for an observed oxygen consumption of 31 mumol/g dry weight X min. With [3-13C]pyruvate as substrate, resonances of aspartate C-2 and C-3 and of alanine C-3 were well resolved in addition to those of glutamate C-2, C-3, and C-4. Nonlinear least squares fitting of these data to the model gave nonrandomly distributed residuals for the 13C fractional enrichments of glutamate C-4, suggesting an incomplete model, but a well determined cycle flux of 11.9 mumol/g dry weight X min for an oxygen uptake of 35 mumol/g dry weight X min. Our studies demonstrate the practicality of 13C NMR

  14. Making fate and exposure models for freshwater ecotoxicity in life cycle assessment suitable for organic acids and bases.

    PubMed

    van Zelm, Rosalie; Stam, Gea; Huijbregts, Mark A J; van de Meent, Dik

    2013-01-01

    Freshwater fate and exposure factors were determined for organic acids and bases, making use of the knowledge on electrical interaction of ionizing chemicals and their sorption to particles. The fate factor represents the residence time in the environment whereas exposure factors equal the dissolved fraction of a chemical. Multimedia fate, exposure, and effect model USES-LCA was updated to take into account the influence of ionization, based upon the acid dissociation constant (pK(a)) of a chemical, and the environmental pH. Freshwater fate (FF) and exposure (XF) factors were determined for 415 acids and 496 bases emitted to freshwater, air, and soil. The relevance of taking account of the degree of ionization of chemicals was tested by determining the ratio (R) of the new vs. fate and exposure factors determined with USES-LCA suitable for neutral chemicals only. Our results show that the majority of freshwater fate and exposure factors of chemicals that are largely ionized in the environment are larger with the ionics model compared to the factors determined with the neutrals model version. R(FF) ranged from 2.4×10(-1) to 1.6×10(1) for freshwater emissions, from 1.2×10(-2) to 2.0×10(4) for soil emissions and from 5.8×10(-2) to 6.0×10(3) for air emissions, and R(XF) from 5.3×10(-1) to 2.2×10(1). Prediction of changed solid-water partitioning, implying a change in runoff and in removal via sedimentation, and prediction of negligible air-water partition coefficient, leading to negligible volatilization were the main contributors to the changes in freshwater fate factors. PMID:22884491

  15. Measurement of annexin V uptake and lactadherin labeling for the quantification of apoptosis in adherent Tca8113 and ACC-2 cells.

    PubMed

    Hu, T; Shi, J; Jiao, X; Zhou, J; Yin, X

    2008-09-01

    Phosphatidylserine (PS) exposure occurs during the cell death program and fluorescein-labeled lactadherin permits the detection of PS exposure earlier than annexin V in suspended cell lines. Adherent cell lines were studied for this apoptosis-associated phenomenon to determine if PS probing methods are reliable because specific membrane damage may occur during harvesting. Apoptosis was induced in the human tongue squamous carcinoma cell line (Tca8113) and the adenoid cystic carcinoma cell line (ACC-2) by arsenic trioxide. Cells were harvested with a modified procedure and labeled with lactadherin and/or annexin V. PS exposure was localized by confocal microscopy and apoptosis was quantified by flow cytometry. The detachment procedure without trypsinization did not induce cell damage. In competition binding experiments, phospholipid vesicles competed for more than 95 and 90% of lactadherin but only about 75 and 70% of annexin V binding to Tca8113 and ACC-2 cells. These data indicate that PS exposure occurs in three stages during the cell death program and that fluorescein-labeled lactadherin permitted the detection of early PS exposure. A similar pattern of PS exposure has been observed in two malignant cell lines with different adherence, suggesting that this pattern of PS exposure is common in adherent cells. Both lactadherin and annexin V could be used in adherent Tca8113 and ACC-2 cell lines when an appropriate harvesting procedure was used. Lactadherin is more sensitive than annexin V for the detection of PS exposure as the physical structure of PS in these blebs and condensed apoptotic cell surface may be more conducive to binding lactadherin than annexin V. PMID:18820763

  16. Low Temperature, Rapid Thermal Cycle Annealing of HgCdTe Grown on CdTe/Si

    NASA Astrophysics Data System (ADS)

    Simingalam, Sina; Brill, Gregory; Wijewarnasuriya, Priyalal; Rao, Mulpuri V.

    2015-05-01

    The HgCdTe(MCT) grown on CdTe/Si substrate has a high dislocation density due to lattice mismatch. Thermal cycle annealing (TCA) is effective in reducing the dislocation density. The TCA at high temperatures results in inter-diffusion of the constituent elements across the MCT/CdTe interface. In this study, we observed a reduction in dislocation density with good surface morphology due to proper design of the TCA system, low annealing temperature, and large number of annealing cycles. The ampoule containing the samples is placed in direct contact with the graphite heating tube which helps in increasing the heating and cooling rates of the annealing cycle. To maintain Hg overpressure, Hg is placed in the sample holder, instead of in the ampoule to avoid Hg condensation. The best results were obtained by cycling the annealing temperature between 290°C and 350°C. Anneals were performed by using 32, 64, 128 and 256 cycles. We obtained an etch pit density (EPD) as low as 1 × 106 cm-2. Lower EPD was not achieved either by increasing annealing temperature or number of annealing cycles. Through secondary ion mass spectroscopy analysis, we observed very little inter-diffusion of Cd across the MCT/CdTe interface for the 128 cycle annealing. These results show promise in bridging the gap in the device performance between the MCT material grown on CdTe/Si and CdZnTe substrates.

  17. Short-chain fatty acid-initiated cell cycle arrest and apoptosis of colonic epithelial cells is linked to mitochondrial function.

    PubMed

    Heerdt, B G; Houston, M A; Augenlicht, L H

    1997-05-01

    Butyrate, a short-chain fatty acid produced during microbial fermentation of fiber, induces growth arrest, differentiation, and apoptosis of colonic epithelial cells in vitro, and our prior work has shown that this induction is tightly linked to mitochondrial activity. Here we demonstrate that 12 h following induction, SW620 human colonic carcinoma cells accumulate simultaneously in G0-G1 and G2-M of the cell cycle. Four h later, during this G0-G1 to G2-M arrest, cells begin to undergo apoptosis. Using a series of unrelated agents that modulate mitochondrial functions, we demonstrate that mitochondrial electron transport and membrane potential are critical in initiation of this butyrate-mediated growth arrest and apoptosis. Colonic tumorigenesis is characterized by abnormalities in proliferation, apoptosis, and mitochondrial activities. Thus, butyrate may reduce risk for colon cancer by inducing a pathway that enhances mitochondrial function, ultimately resulting in initiation of growth arrest and apoptosis of colonic epithelial cells. PMID:9149903

  18. Graphite and fiberglass additives for improving high-rate partial-state-of-charge cycle life of valve-regulated lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Valenciano, J.; Sánchez, A.; Trinidad, F.; Hollenkamp, A. F.

    In order to accommodate regenerative braking energy input in hybrid and mild hybrid vehicles while maintaining boosting power at high rates of discharge, valve-regulated lead-acid (VRLA) batteries must operate permanently at partial-state-of-charge (PSoC) conditions. As a consequence, new failure modes appear, e.g., irreversible sulfation in negative plates, that have to be overcome. In this way, work has been done to apply some solutions like improving charge acceptance in this "sulfated medium". Several batches of 6 V 20 Ah AGM VRLA batteries with spiral cell design have been assembled and tested, each batch containing novel additives in the negative active material (NAM). It has been observed that the addition of a sufficient amount of expanded graphite significantly improves cycle life under PSoC conditions. Moreover, life duration is also extended, although to a lesser extent, by using a novel fiberglass which increases surface area of NAM.

  19. The seed's protein and oil content, fatty acid composition, and growing cycle length of a single genotype of chia (Salvia hispanica L.) as affected by environmental factors.

    PubMed

    Ayerza, Ricardo

    2009-01-01

    As a botanical source, variability in chia seed composition could be expected between growing locations, and between years within a location, due to genotype and environment effects as well genetic x environment's interactions. The objective of the present study was to determine the location effect on the growing cycle length, and seed's protein content, lipid content, and fatty acid profiles, of a single chia genotype. Seeds of chia genotype Tzotzol grown on eight sites in five different ecosystems were tested. One site was in Argentina, in the Semi-Arid Chaco ecosystem (T(5)); one was in Bolivia, in the Sub-Humid Chaco ecosystem (T(4)); and six in Ecuador, one in the Coastal Desert (T(3)), two on the Tropical Rain Forest (T(2)), and three in the Inter-Andean Dry Valley ecosystem (T(1)). Seeds from plants grown in T(4) and in T(3) contained significantly (P <0.05) more protein percentage than did seeds from the other three ecosystems. No significant (P <0.05) differences in protein content were found between T(3) and T(4), and between T(1), T(2), and T(5). Seeds from T(1) and T(5) ecosystems, with 33.5 and 32.2%, respectively, were the numerically highest oil content producers, but their results were only significantly (P <0.05) higher when compared with the T(2) seeds. Significant (P <0.05) differences in palmitic, stearic, oleic, linoleic and alpha-linolenic fatty acids between oils from seeds grown in different ecosystems were detected, however. Oil of seeds grown in the T(3) ecosystem had the palmitic, stearic and oleic fatty acids' highest contents. Palmitic and oleic fatty acid levels were significantly (P <0.05) higher when were compared to that of seeds grown in the T(1) ecosystem, and stearic when was compared to that of seeds grown in the T(5) ecosystem; omega-6 linoleic fatty acid content was significantly (P <0.05) lower in oils of seeds produced in T(1), and T(2) than in those produced in T(3), T(4), and T(5) ecosystems; omega-3 alpha-linolenic fatty

  20. Cdc2 H1 kinase is negatively regulated by a type 2A phosphatase in the Xenopus early embryonic cell cycle: evidence from the effects of okadaic acid.

    PubMed Central

    Félix, M A; Cohen, P; Karsenti, E

    1990-01-01

    In Xenopus embryos, the cell cycle is abbreviated to a rapid alternation between interphase and mitosis. The onset of each M phase is induced by the periodic activation of the cdc2 kinase which is triggered by a threshold level of cyclins and apparently involves dephosphorylation of p34cdc2. We have prepared post-ribosomal supernatants from eggs sampled during interphase (interphase extracts) and just before the first mitosis of the early embryonic cell cycle (prophase extracts). In 'interphase extracts', the cdc2 kinase never activates spontaneously upon incubation at room temperature whereas in 'prophase extracts' it does. We show here that in 'interphase extracts', specific inhibition of type 2A phosphatase by okadaic acid induces cdc2 kinase activation. This requires a subthreshold level of cyclin and the presence of a particulate factor in the extract. Inhibition of type 1 phosphatases by inhibitor 1 and inhibitor 2 never results in cdc2 kinase activation. These results demonstrate that during the period of cyclin accumulation, cdc2 kinase activation is inhibited by a type 2A phosphatase. In 'prophase extracts', spontaneous activation of the cdc2 kinase is inhibited by beta-glycerophosphate and NaF, but not by okadaic acid, inhibitor 1 and inhibitor 2 or divalent cation chelation. This demonstrates that when enough cyclin has accumulated, cdc2 kinase activation involves a protein phosphatase which must be distinct from the type 1 and 2A phosphatases, and from the calcium-dependent (type 2B) and magnesium-dependent (type 2C) phosphatases. Images Fig. 4. PMID:2155777

  1. The all-trans retinoic acid (atRA)-regulated gene Calmin (Clmn) regulates cell cycle exit and neurite outgrowth in murine neuroblastoma (Neuro2a) cells

    SciTech Connect

    Marzinke, Mark A.; Clagett-Dame, Margaret

    2012-01-01

    The vitamin A metabolite all-trans retinoic acid (atRA) functions in nervous system development and regulates cell proliferation and differentiation. Neuroblastoma cells (SH-SY5Y and Neuro2a or N2A) exposed to atRA undergo growth inhibition and neuronal differentiation, both of which are preceded by an increase in Clmn mRNA. Treatment of N2A cells with atRA produces a reduction in phosphohistone 3 immunostaining and BrdU incorporation, both indicators of a reduction in cell proliferation. These effects are nearly eliminated in atRA-treated shClmn knockdown cells. Loss of Clmn in the mouse N2A cell line also results in a significant reduction of atRA-mediated neurite outgrowth, a response that can be rescued by reintroduction of the Clmn sequence. In contrast, ectopic overexpression of Clmn produces an increase in the cyclin dependent kinase inhibitor, p21{sup Cip1}, a decrease in cyclin D1 protein and an increase in hypophosphorylated Rb, showing that Clmn participates in G{sub 1}/S arrest. Clmn overexpression alone is sufficient to inhibit N2A cell proliferation, whereas both Clmn and atRA must be present to induce neurite outgrowth. This study shows that the atRA-responsive gene Clmn promotes exit from the cell cycle, a requisite event for neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer Calmin is a retinoic acid-responsive gene. Black-Right-Pointing-Pointer Calmin promotes cell cycle exit in N2A cells. Black-Right-Pointing-Pointer Calmin overexpression increases p21Cip1 and decreases cyclin D1. Black-Right-Pointing-Pointer Calmin is required for RA-induced growth inhibition and neurite outgrowth.

  2. Data on cell cycle in breast cancer cell line, MDA-MB-231 with ferulic acid treatment.

    PubMed

    Park, Eunmi

    2016-06-01

    Inhibition to repair DNA metabolism to respond to damaged DNA can lead to genetic instability, resulting in cancer cell death (Audeh et al., 2010; Bryant et al., 2005; Farmer et al., 2005; Lukas et al., 2003; Tutt et al., 2010) [1], [2], [6], [8], [11]. Despite of various studies demonstrating efficiency of combination therapy through down-regulation of DNA repair pathway, the suppression effects of DNA repair pathway by chemotherapeutic agents from natural bioactive compounds are less understood (Eitsuka et al., 2014; Kastan et al., 2004; Kawabata et al., 2000; Mancuso et al., 2014) [5], [7], [9]. Here, the data shows that ferulic acid reduced the S-phases post to UV treatment in breast cancer cells and was hypersensitive in breast cancer cells, MDA-MB-231. PMID:26958638

  3. Data on cell cycle in breast cancer cell line, MDA-MB-231 with ferulic acid treatment

    PubMed Central

    Park, Eunmi

    2016-01-01

    Inhibition to repair DNA metabolism to respond to damaged DNA can lead to genetic instability, resulting in cancer cell death (Audeh et al., 2010; Bryant et al., 2005; Farmer et al., 2005; Lukas et al., 2003; Tutt et al., 2010) [1], [2], [6], [8], [11]. Despite of various studies demonstrating efficiency of combination therapy through down-regulation of DNA repair pathway, the suppression effects of DNA repair pathway by chemotherapeutic agents from natural bioactive compounds are less understood (Eitsuka et al., 2014; Kastan et al., 2004; Kawabata et al., 2000; Mancuso et al., 2014) [5], [7], [9]. Here, the data shows that ferulic acid reduced the S-phases post to UV treatment in breast cancer cells and was hypersensitive in breast cancer cells, MDA-MB-231. PMID:26958638

  4. Mercury cycling in boreal ecosystems: The long-term effect of acid rain constituents on peatland pore water methylmercury concentrations

    NASA Astrophysics Data System (ADS)

    Branfireun, Brian A.; Bishop, Kevin; Roulet, Nigel T.; Granberg, Gunnar; Nilsson, Mats

    Sulphate-reducing bacteria have been identified as primary methylators of mercury (Hg) in the laboratory and in field investigations. However, no studies have investigated the effect of long-term deposition of sulphate on methylmercury (MeHg) dynamics in peatlands, which are known to be significant sources of MeHg to downstream waters in the boreal forest zone. As an ancillary experiment to a larger project investigating the effects of acid rain constituents on peatland carbon dynamics, the influence of experimentally elevated Na2SO4 and/or NH4NO3 deposition on peat pore water MeHg concentrations was determined using a simple mesocosm experimental design. After three years, additions of S in amounts equivalent to the 1980s dry and wet deposition in Southern Sweden resulted in peat pore water MeHg concentrations up to six times above background levels. Elevated N loads had no effect on pore water MeHg concentrations.

  5. An efficient proton-coupled electron-transfer process during oxidation of ferulic acid by horseradish peroxidase: coming full cycle.

    PubMed

    Derat, Etienne; Shaik, Sason

    2006-10-25

    Quantum mechanics/molecular mechanics calculations were utilized to study the process of oxidation of a native substrate (ferulic acid) by the active species of horseradish peroxidase (Dunford, H. B. Heme Peroxidases; Wiley-VCH: New York, 1999), Compound I and Compound II, and the manner by which the enzyme returns to its resting state. The results match experimental findings and reveal additional novel features. The calculations demonstrate that both oxidation processes are initiated by a proton-coupled electron-transfer (PCET) step, in which the active species of the enzyme participate only as electron-transfer partners, while the entire proton-transfer event is being relayed from the substrate to and from the His42 residue by a water molecule (W402). The reason for the observed (Henriksen, A; Smith, A. T.; Gajhede, M. J. Biol. Chem. 1999, 274, 35005-35011) similar reactivities of Compound I and Compound II toward ferulic acid is that the reactive isomer of Compound II is the, hitherto unobserved, Por(*)(+)Fe(III)OH isomer that resembles Compound I. The PCET mechanism reveals that His42 and W402 are crucial moieties and they determine the function of the HRP enzyme and account for its ability to perform substrate oxidation (Poulos, T. L. Peroxidases and Cytochrome P450. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: New York, 2000; Vol. 4, pp 189). In view of the results, the possibility of manipulating substrate oxidation by magnetic fields is an intriguing possibility. PMID:17044722

  6. Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

    SciTech Connect

    McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D.

    1996-10-16

    This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

  7. From CO2 to cell: energetic expense of creating biomass using the Calvin-Benson-Bassham and reductive citric acid cycles based on genome data.

    PubMed

    Mangiapia, Mary; Scott, Kathleen

    2016-04-01

    The factors driving the dominance of the Calvin-Benson-Bassham cycle (CBB) or reductive citric acid cycle (rCAC) in autotrophic microorganisms in different habitats are debated. Based on costs for synthesizing a few metabolic intermediates, it has been suggested that the CBB poses a disadvantage due to higher metabolic cost. The purpose of this study was to extend this estimate of cost from metabolite synthesis to biomass synthesis. For 12 gammaproteobacteria (CBB) and five epsilonproteobacteria (rCAC), the amount of ATP to synthesize a gram of biomass from CO2 was calculated from genome sequences via metabolic maps. The eleven central carbon metabolites needed to synthesize biomass were all less expensive to synthesize via the rCAC (66%-89% of the ATP needed to synthesize them via CBB). Differences in cell compositions did result in differing demands for metabolites among the organisms, but the differences in cost to synthesize biomass were small among organisms that used a particular pathway (e.g. rCAC), compared to the difference between pathways (rCAC versus CBB). The rCAC autotrophs averaged 0.195 moles ATP per g biomass, while their CBB counterparts averaged 0.238. This is the first in silico estimate of the relative expense of both pathways to generate biomass. PMID:26940292

  8. Non-growing Rhodopseudomonas palustris Increases the Hydrogen Gas Yield from Acetate by Shifting from the Glyoxylate Shunt to the Tricarboxylic Acid Cycle*

    PubMed Central

    McKinlay, James B.; Oda, Yasuhiro; Rühl, Martin; Posto, Amanda L.; Sauer, Uwe; Harwood, Caroline S.

    2014-01-01

    When starved for nitrogen, non-growing cells of the photosynthetic bacterium Rhodopseudomonas palustris continue to metabolize acetate and produce H2, an important industrial chemical and potential biofuel. The enzyme nitrogenase catalyzes H2 formation. The highest H2 yields are obtained when cells are deprived of N2 and thus use available electrons to synthesize H2 as the exclusive product of nitrogenase. To understand how R. palustris responds metabolically to increase H2 yields when it is starved for N2, and thus not growing, we tracked changes in biomass composition and global transcript levels. In addition to a 3.5-fold higher H2 yield by non-growing cells we also observed an accumulation of polyhydroxybutyrate to over 30% of the dry cell weight. The transcriptome of R. palustris showed down-regulation of biosynthetic processes and up-regulation of nitrogen scavenging mechanisms in response to N2 starvation but gene expression changes did not point to metabolic activities that could generate the reductant necessary to explain the high H2 yield. We therefore tracked 13C-labeled acetate through central metabolic pathways. We found that non-growing cells shifted their metabolism to use the tricarboxylic acid cycle to metabolize acetate in contrast to growing cells, which used the glyoxylate cycle exclusively. This shift enabled cells to more fully oxidize acetate, providing the necessary reducing power to explain the high H2 yield. PMID:24302724

  9. Environmental analysis of plastic production processes: comparing petroleum-based polypropylene and polyethylene with biologically-based poly-beta-hydroxybutyric acid using life cycle analysis.

    PubMed

    Harding, K G; Dennis, J S; von Blottnitz, H; Harrison, S T L

    2007-05-31

    Polymers based on olefins have wide commercial applicability. However, they are made from non-renewable resources and are characterised by difficulty in disposal where recycle and re-use is not feasible. Poly-beta-hydroxybutyric acid (PHB) provides one example of a polymer made from renewable resources. Before motivating its widespread use, the advantages of a renewable polymer must be weighed against the environmental aspects of its production. Previous studies relating the environmental impacts of petroleum-based and bio-plastics have centred on the impact categories of global warming and fossil fuel depletion. Cradle-to-grave studies report equivalent or reduced global warming impacts, in comparison to equivalent polyolefin processes. This stems from a perceived CO(2) neutral status of the renewable resource. Indeed, no previous work has reported the results of a life cycle assessment (LCA) giving the environmental impacts in all major categories. This study investigates a cradle-to-gate LCA of PHB production taking into account net CO(2) generation and all major impact categories. It compares the findings with similar studies of polypropylene (PP) and polyethylene (PE). It is found that, in all of the life cycle categories, PHB is superior to PP. Energy requirements are slightly lower than previously observed and significantly lower than those for polyolefin production. PE impacts are lower than PHB values in acidification and eutrophication. PMID:17400318

  10. The Multiple DSF-family QS Signals are Synthesized from Carbohydrate and Branched-chain Amino Acids via the FAS Elongation Cycle

    PubMed Central

    Zhou, Lian; Yu, Yonghong; Chen, Xiping; Diab, Abdelgader Abdeen; Ruan, Lifang; He, Jin; Wang, Haihong; He, Ya-Wen

    2015-01-01

    Members of the diffusible signal factor (DSF) family are a novel class of quorum sensing (QS) signals in diverse Gram-negative bacteria. Although previous studies have identified RpfF as a key enzyme for the biosynthesis of DSF family signals, many questions in their biosynthesis remain to be addressed. In this study with the phytopathogen Xanthomonas campestris pv. campestris (Xcc), we show that Xcc produces four DSF-family signals (DSF, BDSF, CDSF and IDSF) during cell culture, and that IDSF is a new functional signal characterized as cis-10-methyl-2-dodecenoic acid. Using a range of defined media, we further demonstrate that Xcc mainly produces BDSF in the presence of carbohydrates; leucine and valine are the primary precursor for DSF biosynthesis; isoleucine is the primary precursor for IDSF biosynthesis. Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF. Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals. Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals. PMID:26289160

  11. Inhibition of histone deacetylases by trans-cinnamic acid and its antitumor effect against colon cancer xenografts in athymic mice.

    PubMed

    Zhu, Bingyan; Shang, Boyang; Li, Yi; Zhen, Yongsu

    2016-05-01

    Previous studies have shown that trans-cinnamic acid (tCA) has a broad spectrum of biological activities, and exhibits antioxidant, anti-inflammatory and anticancer properties. In addition, tCA and a variety of its analogs have been detected as gut microbe‑derived metabolites exerting various biological effects in the colon. The aim of this study was to assess the antitumor activity of tCA in vitro and in vivo, in particular its therapeutic efficacy against colon cancer xenografts in athymic mice. Furthermore, it aimed to examine the effects of tCA on histone deacetylases (HDACs) and to identify the underlying molecular mechanisms. Using an MTT assay, tCA was observed to inhibit the proliferation of several cancer cell lines, and the half maximal inhibitory concentration (IC50) in HT29 colon carcinoma cells was ~1 mM. Western blot analysis demonstrated that tCA upregulated the expression of acetyl‑H3 and acetyl‑H4 proteins, which was consistent with the effects of the HDAC inhibitor, trichostatin A (TSA). Furthermore, expression of Bcl‑2 (a marker of cell proliferation) was reduced, and apoptosis was induced. Apoptosis was shown by the activation of cleavage of poly ADP ribose polymerase and the increased expression of Bax. Apoptosis was also confirmed using APC Annexin V and SYTOX Green Nucleic Acid Stain. In addition, the tCA‑induced inhibition of the expression of HDAC markers and activation of apoptosis in tumor tissues were further confirmed by immunohistochemistry. Intragastric administration of tCA at doses of 1.0 and 1.5 mmol/kg body weight suppressed the growth of HT29 human colon carcinoma xenografts in athymic mice at well‑tolerated doses. No toxic changes were found in the heart, lung, liver, kidney, colon or bone marrow following histopathological examination. This study indicated that tCA is effective against colon cancer xenograft in nude mice. The antitumor mechanism of tCA was mediated, at least in part, by inhibition of HDACs in

  12. Inhibition of histone deacetylases by trans-cinnamic acid and its antitumor effect against colon cancer xenografts in athymic mice

    PubMed Central

    ZHU, BINGYAN; SHANG, BOYANG; LI, YI; ZHEN, YONGSU

    2016-01-01

    Previous studies have shown that trans-cinnamic acid (tCA) has a broad spectrum of biological activities, and exhibits antioxidant, anti-inflammatory and anticancer properties. In addition, tCA and a variety of its analogs have been detected as gut microbe-derived metabolites exerting various biological effects in the colon. The aim of this study was to assess the antitumor activity of tCA in vitro and in vivo, in particular its therapeutic efficacy against colon cancer xenografts in athymic mice. Furthermore, it aimed to examine the effects of tCA on histone deacetylases (HDACs) and to identify the underlying molecular mechanisms. Using an MTT assay, tCA was observed to inhibit the proliferation of several cancer cell lines, and the half maximal inhibitory concentration (IC50) in HT29 colon carcinoma cells was ~1 mM. Western blot analysis demonstrated that tCA upregulated the expression of acetyl-H3 and acetyl-H4 proteins, which was consistent with the effects of the HDAC inhibitor, trichostatin A (TSA). Furthermore, expression of Bcl-2 (a marker of cell proliferation) was reduced, and apoptosis was induced. Apoptosis was shown by the activation of cleavage of poly ADP ribose polymerase and the increased expression of Bax. Apoptosis was also confirmed using APC Annexin V and SYTOX Green Nucleic Acid Stain. In addition, the tCA-induced inhibition of the expression of HDAC markers and activation of apoptosis in tumor tissues were further confirmed by immunohistochemistry. Intragastric administration of tCA at doses of 1.0 and 1.5 mmol/kg body weight suppressed the growth of HT29 human colon carcinoma xenografts in athymic mice at well-tolerated doses. No toxic changes were found in the heart, lung, liver, kidney, colon or bone marrow following histopathological examination. This study indicated that tCA is effective against colon cancer xenograft in nude mice. The antitumor mechanism of tCA was mediated, at least in part, by inhibition of HDACs in cancer cells. As

  13. Stomatal responses to CO2 during a diel Crassulacean acid metabolism cycle in Kalanchoe daigremontiana and Kalanchoe pinnata.

    PubMed

    von Caemmerer, Susanne; Griffiths, Howard

    2009-05-01

    To investigate the diurnal variation of stomatal sensitivity to CO2, stomatal response to a 30 min pulse of low CO2 was measured four times during a 24 h time-course in two Crassulacean acid metabolism (CAM) species Kalanchoe daigremontiana and Kalanchoe pinnata, which vary in the degree of succulence, and hence, expression and commitment to CAM. In both species, stomata opened in response to a reduction in pCO2 in the dark and in the latter half of the light period, and thus in CAM species, chloroplast photosynthesis is not required for the stomatal response to low pCO2. Stomata did not respond to a decreased pCO2 in K. daigremontiana in the light when stomata were closed, even when the supply of internal CO2 was experimentally reduced. We conclude that stomatal closure during phase III is not solely mediated by high internal pCO2, and suggest that in CAM species the diurnal variability in the responsiveness of stomata to pCO2 could be explained by hypothesizing the existence of a single CO2 sensor which interacts with other signalling pathways. When not perturbed by low pCO2, CO2 assimilation rate and stomatal conductance were correlated both in the light and in the dark in both species. PMID:19210641

  14. Protein precipitation of diluted samples in SDS-containing buffer with acetone leads to higher protein recovery and reproducibility in comparison with TCA/acetone approach.

    PubMed

    Santa, Cátia; Anjo, Sandra I; Manadas, Bruno

    2016-07-01

    Proteomic approaches are extremely valuable in many fields of research, where mass spectrometry methods have gained an increasing interest, especially because of the ability to perform quantitative analysis. Nonetheless, sample preparation prior to mass spectrometry analysis is of the utmost importance. In this work, two protein precipitation approaches, widely used for cleaning and concentrating protein samples, were tested and compared in very diluted samples solubilized in a strong buffer (containing SDS). The amount of protein recovered after acetone and TCA/acetone precipitation was assessed, as well as the protein identification and relative quantification by SWATH-MS yields were compared with the results from the same sample without precipitation. From this study, it was possible to conclude that in the case of diluted samples in denaturing buffers, the use of cold acetone as precipitation protocol is more favourable than the use of TCA/acetone in terms of reproducibility in protein recovery and number of identified and quantified proteins. Furthermore, the reproducibility in relative quantification of the proteins is even higher in samples precipitated with acetone compared with the original sample. PMID:27094026

  15. The acid and alkalinity budgets of weathering in the Andes-Amazon system: Insights into the erosional control of global biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Torres, Mark A.; West, A. Joshua; Clark, Kathryn E.; Paris, Guillaume; Bouchez, Julien; Ponton, Camilo; Feakins, Sarah J.; Galy, Valier; Adkins, Jess F.

    2016-09-01

    The correlation between chemical weathering fluxes and denudation rates suggests that tectonic activity can force variations in atmospheric pCO2 by modulating weathering fluxes. However, the effect of weathering on pCO2 is not solely determined by the total mass flux. Instead, the effect of weathering on pCO2 also depends upon the balance between 1) alkalinity generation by carbonate and silicate mineral dissolution and 2) sulfuric acid generation by the oxidation of sulfide minerals. In this study, we explore how the balance between acid and alkalinity generation varies with tectonic uplift to better understand the links between tectonics and the long-term carbon cycle. To trace weathering reactions across the transition from the Peruvian Andes to the Amazonian foreland basin, we measured a suite of elemental concentrations (Na, K, Ca, Mg, Sr, Si, Li, SO4, and Cl) and isotopic ratios (87Sr/86Sr and δ34S) on both dissolved and solid phase samples. Using an inverse model, we quantitatively link systematic changes in solute geochemistry with elevation to downstream declines in sulfuric acid weathering as well as the proportion of cations sourced from silicates. With a new carbonate-system framework, we show that weathering in the Andes Mountains is a CO2 source whereas foreland weathering is a CO2 sink. These results are consistent with the theoretical expectation that the ratio of sulfide oxidation to silicate weathering increases with increasing erosion. Altogether, our results suggest that the effect of tectonically-enhanced weathering on atmospheric pCO2 is strongly modulated by sulfide mineral oxidation.

  16. Observations of Sub-3 nm Particles and Sulfuric acid Concentrations during Aerosol Life Cycle Intensive Observation Period 2011 in Long Island, New York

    NASA Astrophysics Data System (ADS)

    Yu, H.; Kanawade, V. P.; You, Y.; Hallar, A. G.; Mccubbin, I. B.; Chirokova, G.; Sedlacek, A. J.; Springston, S. R.; Wang, J.; Kuang, C.; Lee, Y.; McGraw, R. L.; Mikkila, J.; Lee, S.

    2012-12-01

    Atmospheric new particle formation (NPF) is an important source of aerosol particles. But the NPF processes are not well understood, in part because of our limited understanding of the formation of atmospheric sub-3 nm size aerosols and the limited number of simultaneous observations of particle size distributions and the aerosol nucleation precursors. During Aerosol Life Cycle Intensive Observation Period (July-August 2011) in Long Island, New York, we deployed a particle size magnifier (Airmodus A09) running at different working fluid saturation ratios and a TSI CPC3776 to extract the information of sub-3 nm particles formation. A scanning mobility particle spectrometer (SMPS), a chemical ionization mass spectrometer (CIMS), and a number of atmospheric trace gas analyzers were used to simultaneously measure aerosol size distributions, sulfuric acid, and other possible aerosol precursors, respectively. Our observation results show that sub-3 nm particles existed during both NPF and non-NPF events, indicating the formation of sub-3nm particle didn't always lead to NPF characterized by typical banana shaped aerosol size distributions measured by SMPS. However, sub-3 nm particles were much higher during NPF events. Sub-3 nm particles were well-correlated with sulfuric acid showing the same diurnal variations and noontime peaks, especially for NPF days. These results are consistent with laboratory studies showing that formation of sub-3 nm particles is very sensitive to sulfuric acid (than amines and ammonia) [Yu et al. GRL 2012]. HYSPLIT back trajectory analysis indicates that air masses from Great Lakes, containing more SO2, VOCs and secondary organics, may contribute to growth of sub-3 nm particles and NPF.

  17. Effects of Continuous Triiodothyronine Infusion on Citric Acid Cycle in the Normal Immature Swine Heart under Extracorporeal Membrane Oxygenation in vivo

    SciTech Connect

    Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Ledee, Dolena R.; Xu, Chun; Isern, Nancy G.; Olson, Aaron; Portman, Michael A.

    2014-02-13

    Extracorporeal membrane oxygenation (ECMO) is frequently used in infants with postoperative cardiopulmonary failure. ECMO also suppresses circulating triiodothyronine (T3) levels and modifies myocardial metabolism. We assessed the hypothesis that T3 supplementation reverses ECMO induced metabolic abnormalities in the immature heart. Twenty-two male Yorkshire pigs (age 25-38 days) with ECMO were received [2-13C]lactate, [2,4,6,8-13C]octanoate (medium chain fatty acid) and [U-13C]long-chain fatty acids as metabolic tracers either systemically (totally physiological intracoronary concentration) or directly into the coronary artery (high substrate concentration) for the last 60 minutes of each protocol. Nuclear magnetic resonance (NMR) analysis of left ventricular tissue determined the fractional contribution (Fc) of these substrates to the citric acid cycle (CAC). Fifty percent of the pigs in each group received intravenous T3 supplement (bolus at 0.6 μg/kg and then continuous infusion at 0.2 μg/kg/hour) during ECMO. Under both substrate loading conditions T3 significantly increased lactate-Fc with a marginal increase in octanoate-Fc. Both T3 and high substrate provision increased myocardial energy status indexed by [Phosphocreatine]/[ATP]. In conclusion, T3 supplementation promoted lactate metabolism to the CAC during ECMO suggesting that T3 releases inhibition of pyruvate dehydrogenase. Manipulation of substrate utilization by T3 may be used therapeutically during ECMO to improve resting energy state and facilitate weaning.

  18. Okadaic acid overcomes the blocked cell cycle caused by depleting Cdc2-related kinases in Trypanosoma brucei

    SciTech Connect

    Li Ziyin; Tu Xiaoming; Wang, Ching C. . E-mail: ccwang@cgl.ucsf.edu

    2006-11-01

    Mitosis and cytokinesis are highly coordinated in eukaryotic cells. But procyclic-form Trypanosoma brucei under G1 or mitotic arrest is still capable of dividing, resulting in anucleate daughter cells (zoids). Okadaic acid (OKA), an inhibitor of protein phosphatases PP1 and PP2A, is known to inhibit kinetoplast replication and cell division yielding multinucleate cells with single kinetoplasts. However, when OKA was applied to cells arrested in G1 or G2/M phase via RNAi knockdown of specific cdc2-related kinases (CRKs), DNA synthesis and nuclear division were resumed without kinetoplast replication or cell division, resulting in multinucleate cells as in the wild type. Cells arrested in G2/M via depleting the mitotic cyclin CycB2 or an aurora B kinase homologue TbAUK1 were, however, not released by OKA treatment. The phenomenon is thus similar to the OKA activation of Cdc2 in Xenopus oocyte by inhibiting PP2A [Maton, et al., Differential regulation of Cdc2 and Aurora-A in Xenopus oocytes: a crucial role of phosphatase 2A. J. Cell Sci. 118 (2005) 2485-2494]. A simultaneous knockdown of the seven PP1s or the PP2A catalytic subunit in T. brucei by RNA interference did not, however, result in multinucleate cells. This could be explained by assuming a negative regulation, either directly or indirectly, of CRK by an OKA-sensitive phosphatase, which could be a PP2A as in the Xenopus oocyte and a positive regulation of kinetoplast replication by an OKA-susceptible protein(s). Test of a PP2A-specific inhibitor, fostriecin, on cells arrested in G2/M via CRK depletion or a knockdown of the PP2A catalytic subunit from the CRK-depleted cells both showed a partial lift of the G2/M block without forming multinucleate cells. These observations support the abovementioned assumption and suggest the presence of a novel OKA-sensitive protein(s) regulating kinetoplast replication that still remains to be identified.

  19. Modulation of fatty acid and bile acid metabolism by PPARα protects against alcoholic liver disease

    PubMed Central

    Li, Heng-Hong; Tyburski, John B.; Wang, Yiwen; Strawn, Steve; Moon, Bo-Hyun; Kallakury, Bhaskar V. S.; Gonzalez, Frank J.; Fornace, Albert J.

    2014-01-01

    Background Chronic alcohol intake affects liver function and causes hepatic pathological changes. It has been shown that peroxisome proliferator-activated receptor α (PPARα)-null mice developed more pronounced hepatic changes than wild type (WT) mice after chronic exposure to a diet containing 4% alcohol. The remarkable similarity between the histopathology of ALD in Ppara-null model and in humans, and the fact that PPARα expression and activity in human liver are less than one-tenth of those in WT mouse liver make Ppara-null a good system to investigate ALD. Methods In this study, the Ppara-null model was used to elucidate the dynamic regulation of PPARα activity during chronic alcohol intake. Hepatic transcriptomic and metabolomic analyses were used to examine alterations of gene expression and metabolites associated with pathological changes. The changes triggered by alcohol consumption on gene expression and metabolites in Ppara-null mice were compared with those in wild-type mice. Results The results showed that in the presence of PPARα, three major metabolic pathways in mitochondria, namely the fatty acid β-oxidation, the tricarboxylic acid cycle (TCA) and the electron transfer chain, were induced in response to two-month alcohol feeding, while these responses were greatly reduced in the absence of PPARα. In line with the transcriptional modulations of these metabolic pathways, lipidomic profiling showed consistent accumulation of triglycerides in Ppara-null mice, a robust increase of hepatic cholic acid and its derivatives, and a strong induction of fibrogenesis genes exclusively in alcohol-fed Ppara-null mice. Conclusions These observations indicate that PPARα plays a protective role to enhance mitochondrial function in response to chronic alcohol consumption by adaptive transcriptional activation and suggest that activation of this nuclear receptor may be of therapeutic value in the treatment of ALD. PMID:24773203

  20. Trichloroacetic acid in the vegetation of polluted and remote areas of both hemispheres—Part I. Its formation, uptake and geographical distribution

    NASA Astrophysics Data System (ADS)

    Weissflog, Ludwig; Pfennigsdorff, Andrea; Martinez-Pastur, Guillermo; Puliafito, Enrique; Figueroa, Dante; Elansky, Nikolai; Nikonov, Vyasheslav; Putz, Erich; Krüger, Gert; Kellner, Klaus

    Trichloroacetic acid (TCA; CCl 3COOH) is a phytotoxic chemical. Although TCA salts and derivatives were once deployed as herbicides against perennial grasses and weeds, their use has since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, high-volatile C 2-chlorohydrocarbons tetrachloroethene (TECE, C 2Cl 4) and 1,1,1-trichloroethane (TCE, CCl 3CH 3) can react to TCA and other substances under oxidative conditions here. Owing to further industrialisation of Southeast Asia, South Africa and South America, a rise can be expected in the use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere (SH). The increasing emissions of this substance—together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the SH—will result in the increased input/formation of TCA in the vegetation located on the lee side of these emission sources. By means of biomonitoring studies, inputs/formation of TCA related to the climatic conditions were detected at various locations in South America, Africa, and Europe.

  1. The impact of acid mine drainage on the methylmercury cycling at the sediment-water interface in Aha Reservoir, Guizhou, China.

    PubMed

    He, Tianrong; Zhu, Yuzhen; Yin, Deliang; Luo, Guangjun; An, Yanlin; Yan, HaiYu; Qian, Xiaoli

    2015-04-01

    The methylmercury (MeHg) cycling at water-sediment interface in an acid mine drainage (AMD)-polluted reservoir (Aha Reservoir) and a reference site (Hongfeng Reservoir) were investigated and compared. Both reservoirs are seasonal anoxic and alkaline. The concentrations of sulfate, sulfide, iron, and manganese in Aha Reservoir were enriched compared to the reference levels in Hongfeng reservoir due to the AMD input. It was found that the MeHg accumulation layer in Aha Reservoir transitioned from the top sediment layer in winter to the water-sediment interface in spring and then to the overlying water above sediment in summer. It supported the assumption that spring methylation activity may start in sediments and migrate into the water column with seasonal variation. The weaker methylation in sediment during spring and summer was caused by the excessive sulfide (∼15-20 μM) that reduced the bioavailability of mercury, while sulfate reduction potential was in the optimal range for the methylation in the overlying water. This led to a transport flux of MeHg from water to sediment in spring and summer. In contrast, such inversion of MeHg accumulation layer did not occur in Hongfeng Reservoir. The sulfate reduction potential was in the optimal range for the methylation in top sediment, and dissolved MeHg was positively related to sulfide in pore water of Hongfeng Reservoir (r = 0.67, p < 0.001). This result suggested that accumulation of MeHg in lake water and cycling of MeHg at sediment-water interface associate with some sensitive environmental factors, such as sulfur. PMID:25483970

  2. Combined Sulfur K-edge XANES Spectroscopy and Stable Isotope Analysis of Fulvic Acids and Groundwater Sulfate Identify Sulfur Cycling in a Karstic Catchment Area

    SciTech Connect

    Einsiedl,F.; Schafer, T.; Northrup, P.

    2007-01-01

    Chemical and isotope analyses on groundwater sulfate, atmospheric deposition sulfate and fulvic acids (FAs) associated sulfur were used to determine the S cycling in a karstic catchment area of the Franconian Alb, Southern Germany. Sulfur K-edge X-ray absorption near edge structure (XANES) spectroscopy provided information on the oxidation state and the mechanism of the incorporation of sulfur in FAs. During base flow {delta}{sup 34}S values of groundwater sulfate were slightly depleted to those of recent atmospheric sulfate deposition with mean amount-weighted {delta}{sup 34}S values of around + 3{per_thousand}. The {delta}{sup 18}O values of groundwater sulfate shifted to lower values compared to those of atmospheric deposition and indicated steadiness from base flow to peak flow. The reduced sulfur species (S{sub -1}/thiol; S{sub 0}/thiophene, disulfide, S{sub +2}2/sulfoxide) of soil FAs averaged around 49% of the total sulfur and {delta}{sup 34}S value in FAs was found to be 0.5{per_thousand}. The formation of polysulfides and thiols in FAs in concert with a decreasing isotope value of {delta}{sup 34}S in FAs with respect to those of atmospheric deposition sulfate suggests oxidation of H{sub 2}S, enriched in the {sup 32}S isotope, with organic material. The depletion of {delta}{sup 18}O-SO{sub 4}{sup 2-} by several per mil in groundwater sulfate with respect to those of atmospheric deposition is, therefore, consistent with the hypothesis that SO{sub 4}{sup 2-} has been cycled through the organic S pool as well as that groundwater sulfate is formed by oxidation of H{sub 2}S with organic matter in the mineral soil of the catchment area.

  3. Inhibition of phosphotidylinositol-3 kinase pathway by a novel naphthol derivative of betulinic acid induces cell cycle arrest and apoptosis in cancer cells of different origin

    PubMed Central

    Majeed, R; Hamid, A; Sangwan, P L; Chinthakindi, P K; Koul, S; Rayees, S; Singh, G; Mondhe, D M; Mintoo, M J; Singh, S K; Rath, S K; Saxena, A K

    2014-01-01

    Betulinic acid (BA) is a pentacyclic triterpenoid natural product reported to inhibit cell growth in a variety of cancers. However, the further clinical development of BA got hampered because of poor solubility and pharmacological properties. Interestingly, this molecule offer several hotspots for structural modifications in order to address its associated issues. In our endeavor, we selected C-3 position for the desirable chemical modification in order to improve its cytotoxic and pharmacological potential and prepared a library of different triazoline derivatives of BA. Among them, we previously reported the identification of a potential molecule, that is, 3{1N(5-hydroxy-naphth-1yl)-1H-1,2,3-triazol-4yl}methyloxy betulinic acid (HBA) with significant inhibition of cancer cell growth and their properties. In the present study, we have shown for the first time that HBA decreased the expression of phosphotidylinositol-3 kinase (PI3K) p110α and p85α and caused significant downregulation of pAKT and of NFκB using human leukemia and breast cancer cells as in vitro models. Further it was revealed that PI3K inhibition by HBA induced cell cycle arrest via effects on different cell cycle regulatory proteins that include CDKis cyclins and pGSK3β. Also, this target-specific inhibition was associated with mitochondrial apoptosis as was reflected by the increased expression of mitochondrial bax, downregulated bcl2 and decreased mitochondrial levels of cytochrome c, together with reactive oxygen species generation and decline in mitochondrial membrane potential. The apoptotic effectors such as caspase 8, caspase 9 and caspase 3 were found to be upregulated besides DNA repair-associated enzyme, that is, PARP cleavage caused cancer cell death. Pharmacodynamic evaluation revealed that both HBA and BA were safe upto the dose of 2000 mg/kg body weight and with acceptable pharmacodynamic parameters. The in vitro data corroborated with in vivo anticancer activity wherein Ehrlich

  4. Synergistic anticancer properties of docosahexaenoic acid and 5-fluorouracil through interference with energy metabolism and cell cycle arrest in human gastric cancer cell line AGS cells

    PubMed Central

    Gao, Kun; Liang, Qi; Zhao, Zhi-Hao; Li, You-Fen; Wang, Shu-Feng

    2016-01-01

    AIM: To explore the synergistic effect of docosahexaenoic acid (DHA)/5-fluorouracil (5-FU) on the human gastric cancer cell line AGS and examine the underlying mechanism. METHODS: AGS cells were cultured and treated with a series of concentrations of DHA and 5-FU alone or in combination for 24 and 48 h. To investigate the synergistic effect of DHA and 5-FU on AGS cells, the inhibition of cell proliferation was determined by MTT assay and cell morphology. Flow cytometric analysis was also used to assess cell cycle distribution, and the expression of mitochondrial electron transfer chain complexes (METCs) I, II and V in AGS cells was further determined by Western blot analysis. RESULTS: DHA and 5-FU alone or in combination could markedly suppress the proliferation of AGS cells in a significant time and dose-dependent manner. DHA markedly strengthened the antiproliferative effect of 5-FU, decreasing the IC50 by 3.56-2.15-fold in an apparent synergy. The morphological changes of the cells were characterized by shrinkage, cell membrane blebbing and decreased adherence. Cell cycle analysis showed a shift of cells into the G0/G1 phase from the S phase following treatment with DHA or 5-FU (G0/G1 phase: 30.04% ± 1.54% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 56.76% ± 3.14% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). Combination treatment of DHA and 5-FU resulted in a significantly larger shift toward the G0/G1 phase and subsequent reduction in S phase (G0/G1 phase: 69.06% ± 2.63% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 19.80% ± 4.30% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). This synergy was also reflected in the significant downregulation of the expression of METCs in AGS cells. CONCLUSION: Synergistic anticancer properties of DHA and 5-FU may involve interference with energy production of AGS cells via downregulation of METCs and cell cycle arrest. PMID

  5. Mode of action and resistance studies unveil new roles for tropodithietic acid as an anticancer agent and the γ-glutamyl cycle as a proton sink

    PubMed Central

    Wilson, Maxwell Z.; Wang, Rurun; Gitai, Zemer; Seyedsayamdost, Mohammad R.

    2016-01-01

    While we have come to appreciate the architectural complexity of microbially synthesized secondary metabolites, far less attention has been paid to linking their structural features with possible modes of action. This is certainly the case with tropodithietic acid (TDA), a broad-spectrum antibiotic generated by marine bacteria that engage in dynamic symbioses with microscopic algae. TDA promotes algal health by killing unwanted marine pathogens; however, its mode of action (MoA) and significance for the survival of an algal–bacterial miniecosystem remains unknown. Using cytological profiling, we herein determine the MoA of TDA and surprisingly find that it acts by a mechanism similar to polyether antibiotics, which are structurally highly divergent. We show that like polyether drugs, TDA collapses the proton motive force by a proton antiport mechanism, in which extracellular protons are exchanged for cytoplasmic cations. The α-carboxy-tropone substructure is ideal for this purpose as the proton can be carried on the carboxyl group, whereas the basicity of the tropylium ion facilitates cation export. Based on similarities to polyether anticancer agents we have further examined TDA’s cytotoxicity and find it to exhibit potent, broad-spectrum anticancer activities. These results highlight the power of MoA-profiling technologies in repurposing old drugs for new targets. In addition, we identify an operon that confers TDA resistance to the producing marine bacteria. Bioinformatic and biochemical analyses of these genes lead to a previously unknown metabolic link between TDA/acid resistance and the γ-glutamyl cycle. The implications of this resistance mechanism in the context of the algal-bacterial symbiosis are discussed. PMID:26802120

  6. Mode of action and resistance studies unveil new roles for tropodithietic acid as an anticancer agent and the γ-glutamyl cycle as a proton sink.

    PubMed

    Wilson, Maxwell Z; Wang, Rurun; Gitai, Zemer; Seyedsayamdost, Mohammad R

    2016-02-01

    While we have come to appreciate the architectural complexity of microbially synthesized secondary metabolites, far less attention has been paid to linking their structural features with possible modes of action. This is certainly the case with tropodithietic acid (TDA), a broad-spectrum antibiotic generated by marine bacteria that engage in dynamic symbioses with microscopic algae. TDA promotes algal health by killing unwanted marine pathogens; however, its mode of action (MoA) and significance for the survival of an algal-bacterial miniecosystem remains unknown. Using cytological profiling, we herein determine the MoA of TDA and surprisingly find that it acts by a mechanism similar to polyether antibiotics, which are structurally highly divergent. We show that like polyether drugs, TDA collapses the proton motive force by a proton antiport mechanism, in which extracellular protons are exchanged for cytoplasmic cations. The α-carboxy-tropone substructure is ideal for this purpose as the proton can be carried on the carboxyl group, whereas the basicity of the tropylium ion facilitates cation export. Based on similarities to polyether anticancer agents we have further examined TDA's cytotoxicity and find it to exhibit potent, broad-spectrum anticancer activities. These results highlight the power of MoA-profiling technologies in repurposing old drugs for new targets. In addition, we identify an operon that confers TDA resistance to the producing marine bacteria. Bioinformatic and biochemical analyses of these genes lead to a previously unknown metabolic link between TDA/acid resistance and the γ-glutamyl cycle. The implications of this resistance mechanism in the context of the algal-bacterial symbiosis are discussed. PMID:26802120

  7. TRIIODOTHYRONINE INCREASES MYOCARDIAL FUNCTION AND PYRUVATE ENTRY INTO THE CITRIC ACID CYCLE AFTER REPERFUSION IN A MODEL OF INFANT CARDIOPULMONARY BYPASS

    SciTech Connect

    Olson, Aaron; Bouchard, Bertrand; Ning, Xue-Han; Isern, Nancy G.; Des Rosiers, Christine; Portman, Michael A.

    2012-03-01

    We utilized a translational model of infant CPB to test the hypothesis that T3 modulates pyruvate entry into the citric acid cycle (CAC) thereby providing the energy support for improved cardiac function after ischemia-reperfusion. Methods and Results: Neonatal piglets received intracoronary [2-13Carbon(13C)]-pyruvate for 40 minutes (8 mM) during control aerobic conditions (Cont) or immediately after reperfusion (IR) from global hypothermic ischemia. A third group (IR-Tr) received T3 (1.2 ug/kg) during reperfusion. We assessed absolute CAC intermediate levels (aCAC) and flux parameters into the CAC through oxidative pyruvate decarboxylation (PDC ) and anaplerotic carboxylation (PC; ) using 13C-labeled pyruvate and isotopomer analysis by gas and liquid chromatography-mass spectrometry and 13C NMR. Neither IR nor IR-Tr modified aCAC. However, compared to IR, T3 (group IR-Tr) increased cardiac power and oxygen consumption after CPB while elevating both PDC and PC (~ four-fold). T3 inhibited IR induced reductions in CAC intermediate molar percent enrichment (MPE) and oxaloacetate(citrate)/malate MPE ratio; an index of aspartate entry into the CAC. Conclusions: T3 markedly enhances PC and PDC thereby providing substrate for elevated cardiac function and work after reperfusion. The increases in pyruvate flux occur with preservation of the CAC intermediate pool. Additionally, T3 inhibition of reductions in CAC intermediate MPEs indicates that T3 reduces the reliance on amino acids (AA) for anaplerosis after reperfusion. Thus, AA should be more available for other functions such as protein synthesis.

  8. Microbial Iron Cycling in Acidic Geothermal Springs of Yellowstone National Park: Integrating Molecular Surveys, Geochemical Processes, and Isolation of Novel Fe-Active Microorganisms

    PubMed Central

    Kozubal, Mark A.; Macur, Richard E.; Jay, Zackary J.; Beam, Jacob P.; Malfatti, Stephanie A.; Tringe, Susannah G.; Kocar, Benjamin D.; Borch, Thomas; Inskeep, William P.

    2012-01-01

    Geochemical, molecular, and physiological analyses of microbial isolates were combined to study the geomicrobiology of acidic iron oxide mats in Yellowstone National Park. Nineteen sampling locations from 11 geothermal springs were studied ranging in temperature from 53 to 88°C and pH 2.4 to 3.6. All iron oxide mats exhibited high diversity of crenarchaeal sequences from the Sulfolobales, Thermoproteales, and Desulfurococcales. The predominant Sulfolobales sequences were highly similar to Metallosphaera yellowstonensis str. MK1, previously isolated from one of these sites. Other groups of archaea were consistently associated with different types of iron oxide mats, including undescribed members of the phyla Thaumarchaeota and Euryarchaeota. Bacterial sequences were dominated by relatives of Hydrogenobaculum spp. above 65–70°C, but increased in diversity below 60°C. Cultivation of relevant iron-oxidizing and iron-reducing microbial isolates included Sulfolobus str. MK3, Sulfobacillus str. MK2, Acidicaldus str. MK6, and a new candidate genus in the Sulfolobales referred to as Sulfolobales str. MK5. Strains MK3 and MK5 are capable of oxidizing ferrous iron autotrophically, while strain MK2 oxidizes iron mixotrophically. Similar rates of iron oxidation were measured for M. yellowstonensis str. MK1 and Sulfolobales str. MK5. Biomineralized phases of ferric iron varied among cultures and field sites, and included ferric oxyhydroxides, K-jarosite, goethite, hematite, and scorodite depending on geochemical conditions. Strains MK5 and MK6 are capable of reducing ferric iron under anaerobic conditions with complex carbon sources. The combination of geochemical and molecular data as well as physiological observations of isolates suggests that the community structure of acidic Fe mats is linked with Fe cycling across temperatures ranging from 53 to 88°C. PMID:22470372

  9. Microbial iron cycling in acidic geothermal springs of yellowstone national park: integrating molecular surveys, geochemical processes, and isolation of novel fe-active microorganisms.

    PubMed

    Kozubal, Mark A; Macur, Richard E; Jay, Zackary J; Beam, Jacob P; Malfatti, Stephanie A; Tringe, Susannah G; Kocar, Benjamin D; Borch, Thomas; Inskeep, William P

    2012-01-01

    Geochemical, molecular, and physiological analyses of microbial isolates were combined to study the geomicrobiology of acidic iron oxide mats in Yellowstone National Park. Nineteen sampling locations from 11 geothermal springs were studied ranging in temperature from 53 to 88°C and pH 2.4 to 3.6. All iron oxide mats exhibited high diversity of crenarchaeal sequences from the Sulfolobales, Thermoproteales, and Desulfurococcales. The predominant Sulfolobales sequences were highly similar to Metallosphaera yellowstonensis str. MK1, previously isolated from one of these sites. Other groups of archaea were consistently associated with different types of iron oxide mats, including undescribed members of the phyla Thaumarchaeota and Euryarchaeota. Bacterial sequences were dominated by relatives of Hydrogenobaculum spp. above 65-70°C, but increased in diversity below 60°C. Cultivation of relevant iron-oxidizing and iron-reducing microbial isolates included Sulfolobus str. MK3, Sulfobacillus str. MK2, Acidicaldus str. MK6, and a new candidate genus in the Sulfolobales referred to as Sulfolobales str. MK5. Strains MK3 and MK5 are capable of oxidizing ferrous iron autotrophically, while strain MK2 oxidizes iron mixotrophically. Similar rates of iron oxidation were measured for M. yellowstonensis str. MK1 and Sulfolobales str. MK5. Biomineralized phases of ferric iron varied among cultures and field sites, and included ferric oxyhydroxides, K-jarosite, goethite, hematite, and scorodite depending on geochemical conditions. Strains MK5 and MK6 are capable of reducing ferric iron under anaerobic conditions with complex carbon sources. The combination of geochemical and molecular data as well as physiological observations of isolates suggests that the community structure of acidic Fe mats is linked with Fe cycling across temperatures ranging from 53 to 88°C. PMID:22470372

  10. Atlas of Rice Grain Filling-Related Metabolism under High Temperature: Joint Analysis of Metabolome and Transcriptome Demonstrated Inhibition of Starch Accumulation and Induction of Amino Acid Accumulation

    PubMed Central

    Yamakawa, Hiromoto; Hakata, Makoto

    2010-01-01

    High temperature impairs grain filling by inhibiting the deposition of storage materials such as starch and protein. To comprehend its impact on grain filling metabolism in rice (Oryza sativa), levels of metabolites and transcripts related to central pathways of metabolism were simultaneously determined in developing caryopses exposed to high temperature (33°C/28°C) and a control temperature (25°C/20°C) during the milky stage. A capillary electrophoresis-based metabolomic analysis revealed that high temperature increased the accumulation of sucrose and pyruvate/ oxaloacetate-derived amino acids and decreased levels of sugar phosphates and organic acids involved in glycolysis/gluconeogenesis and the tricarboxylic acid (TCA) cycle, respectively. A transcriptomic analysis using a whole genome-covering microarray unraveled the possible metabolic steps causing the shortage of storage materials under the elevated temperature. Starch deposition might be impaired by down-regulation of sucrose import/degradation and starch biosynthesis, and/or up-regulation of starch degradation as well as inefficient ATP production by an inhibited cytochrome respiration chain, as indicated by the response of gene expression to high temperature. Amino acid accumulation might be attributed to the heat-stable import of amino acids into the caryopsis and/or repression of protein synthesis especially the tRNA charging step under high temperature. An atlas showing the effect of high temperature on levels of metabolites and gene expression in the central metabolic pathways is presented. PMID:20304786

  11. Titer of trastuzumab produced by a Chinese hamster ovary cell line is associated with tricarboxylic acid cycle activity rather than lactate metabolism.

    PubMed

    Ishii, Yoichi; Imamoto, Yasufumi; Yamamoto, Rie; Tsukahara, Masayoshi; Wakamatsu, Kaori

    2015-04-01

    Achieving high productivity and quality is the final goal of therapeutic antibody development, but the productivity and quality of antibodies are known to be substantially dependent on the nature of the cell lines expressing the antibodies. We characterized two contrasting cell lines that produce trastuzumab, namely cell line A with a high titer and a low aggregate content and cell line B with a low titer and a high aggregate content to identify the causes of the differences. We observed the following differences: cell growth (A > B), proportion of defucosylated oligosaccharides on antibodies (A < B), and proportion of covalent antibody aggregates (A > B). Our results suggest that the high monoclonal antibody (mAb) titers in cell line A is associated with the high proliferation and is not caused by the lactate metabolism shift (switching from lactate production to net lactate consumption). Rather, these differences can be accounted for by the following: levels of tricarboxylic acid cycle intermediates (A > B), ammonium ion levels (A ≤ B), and oxidative stress (A > B). PMID:25449760

  12. [Effect of heavy metals on activity of key enzymes of glyoxylate cycle and content of thiobarbituric acid reactive substances in the germinating soybean Glicine max L.seeds].

    PubMed

    Bezdudnaia, E F; Kaliman, P A

    2008-01-01

    The influence of CoCl2 and CdCl2 on the activity of isocytrate lyase, malate synthase and NAD-malate dehydrogenase in the seed lobes and the composition of malondialdehyde products at early stages of germinating of soybean seeds: after first 24-hours, 72 hours and 96 hours are investigated. It is shown that when germinating in the medium containing no metal salts, isocytrate lyase activity is greatly increased during 96 h and malate synthase is increased after 72 h and is decreased after 96 h of germination period. CoCl2 activated isocytrate lyase activity after 72 hours and decreased malate synthase activity after 96 hours. The lengthening of the primary root under such conditions is noted. CdCl2 inhibited isocytrate lyase activity during first 24 hours and suppressed malate synthase activity after 96 hours. During this process the germ growth is suppressed. CoCl2 increased the composition of malondialdehyde products during each period of germination, and CdCl2 increased malondialdehyde content after 72 and 96 hours. The role of glyoxylate cycle enzymes in transforming fatty acids into carbohydrates and in forming the primary root under the process of germination of seed lobes of soybean is discussed. PMID:18710031

  13. Mitochondrial diaphorases as NAD+ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition

    PubMed Central

    Kiss, Gergely; Konrad, Csaba; Pour-Ghaz, Issa; Mansour, Josef J.; Németh, Beáta; Starkov, Anatoly A.; Adam-Vizi, Vera; Chinopoulos, Christos

    2014-01-01

    Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces high-energy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the α-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintaining the function of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. We addressed the source of the NAD+ supply for KGDHC under anoxic conditions and inhibition of complex I. Using pharmacologic tools and specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity, we showed that mitochondrial diaphorases in the mouse liver contribute up to 81% to the NAD+ pool during respiratory inhibition. Under these conditions, KGDHC's function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD+ derived from diaphorases. Through this process, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by complex III of the respiratory chain.—Kiss, G., Konrad, C., Pour-Ghaz, I., Mansour, J. J., Németh, B., Starkov, A. A., Adam-Vizi, V., Chinopoulos, C. Mitochondrial diaphorases as NAD+ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition. PMID:24391134

  14. microRNA-34a-Upregulated Retinoic Acid-Inducible Gene-I Promotes Apoptosis and Delays Cell Cycle Transition in Cervical Cancer Cells.

    PubMed

    Wang, Jing-Hua; Zhang, Le; Ma, Yu-Wei; Xiao, Jing; Zhang, Yi; Liu, Min; Tang, Hua

    2016-06-01

    The function of retinoic acid-inducible gene-I (RIG-I) in viral replication is well documented, but its function in carcinogenesis and malignancies as well as relationship with microRNAs (miRNAs) remain poorly understood. miR-34a is an antioncogene in multiple tumors. In our study, RIG-I and miR-34a suppressed cell growth, proliferation, migration, and invasion in cervical cancer cells in vitro. miR-34a was validated as a new regulator of RIG-I by binding to its 3' untranslated region and upregulating its expression level. Furthermore, we revealed that RIG-I and miR-34a enhanced apoptosis, delayed the G1/S/G2 transition of the cell cycle, and inhibited the epithelial-mesenchymal transition process to modulate malignancies in cervical cancer cells. Phenotypic rescue experiments indicated that RIG-I mediates the effects of miR-34a in HeLa and C33A cells. These findings provide new insights into the mechanisms that underlie carcinogenesis and may provide new biomarkers for the diagnosis and therapy of cervical cancer. PMID:26910120

  15. Compound-specific nitrogen isotope analysis of amino acids: a possible new tool for reconstruction of paleo-nitrogen sources and cycling

    NASA Astrophysics Data System (ADS)

    Batista, F. C.; Ravelo, A. C.; McCarthy, M. D.

    2010-12-01

    Compound specific nitrogen isotopes of amino acids (δ 15N-AA) are a unique new geochemical tool, increasingly used in modern ecological and food web studies. For the first time, δ15N-AA allows elucidation of the molecular-level basis of whole sedimentary δ15N values and diagenetic alteration of the primary signal. Thus, this technique has implications for paleoceanographic studies of nitrogen cycling, in particular, understanding whole sediment δ15N reconstructions. Here we analyze δ15N-AA on a suite of samples (plankton tows, sediment traps and multicores) collected in the Santa Barbara Basin to investigate preservation and alteration of individual δ15N-AA signals from primary production, through export of primary production from the surface ocean, and finally during early sedimentary diagenesis. We use this sample suite to compare specific aspects of δ15N-AA with bulk δ15N-AA values to explore the potential of these new measurements to: (1) understand the molecular basis of the bulk δ15N-AA record, and (2) monitor specific AA expected to have unaltered δ15N-AA signatures representative of exported primary production.

  16. The Ethylmalonyl-CoA Pathway Is Used in Place of the Glyoxylate Cycle by Methylobacterium extorquens AM1 during Growth on Acetate*

    PubMed Central

    Schneider, Kathrin; Peyraud, Rémi; Kiefer, Patrick; Christen, Philipp; Delmotte, Nathanaël; Massou, Stéphane; Portais, Jean-Charles; Vorholt, Julia A.

    2012-01-01

    Acetyl-CoA assimilation was extensively studied in organisms harboring the glyoxylate cycle. In this study, we analyzed the metabolism of the facultative methylotroph Methylobacterium extorquens AM1, which lacks isocitrate lyase, the key enzyme in the glyoxylate cycle, during growth on acetate. MS/MS-based proteomic analysis revealed that the protein repertoire of M. extorquens AM1 grown on acetate is similar to that of cells grown on methanol and includes enzymes of the ethylmalonyl-CoA (EMC) pathway that were recently shown to operate during growth on methanol. Dynamic 13C labeling experiments indicate the presence of distinct entry points for acetate: the EMC pathway and the TCA cycle. 13C steady-state metabolic flux analysis showed that oxidation of acetyl-CoA occurs predominantly via the TCA cycle and that assimilation occurs via the EMC pathway. Furthermore, acetyl-CoA condenses with the EMC pathway product glyoxylate, resulting in malate formation. The latter, also formed by the TCA cycle, is converted to phosphoglycerate by a reaction sequence that is reversed with respect to the serine cycle. Thus, the results obtained in this study reveal the utilization of common pathways during the growth of M. extorquens AM1 on C1 and C2 compounds, but with a major redirection of flux within the central metabolism. Furthermore, our results indicate that the metabolic flux distribution is highly complex in this model methylotroph during growth on acetate and is fundamentally different from organisms using the glyoxylate cycle. PMID:22105076

  17. A Natural Light/Dark Cycle Regulation of Carbon-Nitrogen Metabolism and Gene Expression in Rice Shoots.

    PubMed

    Li, Haixing; Liang, Zhijun; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2016-01-01

    Light and temperature are two particularly important environmental cues for plant survival. Carbon and nitrogen are two essential macronutrients required for plant growth and development, and cellular carbon and nitrogen metabolism must be tightly coordinated. In order to understand how the natural light/dark cycle regulates carbon and nitrogen metabolism in rice plants, we analyzed the photosynthesis, key carbon-nitrogen metabolites, and enzyme activities, and differentially expressed genes and miRNAs involved in the carbon and nitrogen metabolic pathway in rice shoots at the following times: 2:00, 6:00, 10:00, 14:00, 18:00, and 22:00. Our results indicated that more CO2 was fixed into carbohydrates by a high net photosynthetic rate, respiratory rate, and stomatal conductance in the daytime. Although high levels of the nitrate reductase activity, free ammonium and carbohydrates were exhibited in the daytime, the protein synthesis was not significantly facilitated by the light and temperature. In mRNA sequencing, the carbon and nitrogen metabolism-related differentially expressed genes were obtained, which could be divided into eight groups: photosynthesis, TCA cycle, sugar transport, sugar metabolism, nitrogen transport, nitrogen reduction, amino acid metabolism, and nitrogen regulation. Additionally, a total of 78,306 alternative splicing events have been identified, which primarily belong to alternative 5' donor sites, alternative 3' acceptor sites, intron retention, and exon skipping. In sRNA sequencing, four carbon and nitrogen metabolism-related miRNAs (osa-miR1440b, osa-miR2876-5p, osa-miR1877 and osa-miR5799) were determined to be regulated by natural light/dark cycle. The expression level analysis showed that the four carbon and nitrogen metabolism-related miRNAs negatively regulated their target genes. These results may provide a good strategy to study how natural light/dark cycle regulates carbon and nitrogen metabolism to ensure plant growth and

  18. Inducing cell cycle arrest and apoptosis by dimercaptosuccinic acid modified Fe3O4 magnetic nanoparticles combined with nontoxic concentration of bortezomib and gambogic acid in RPMI-8226 cells

    PubMed Central

    Zhang, Wei; Qiao, Lixing; Wang, Xinchao; Senthilkumar, Ravichandran; Wang, Fei; Chen, Baoan

    2015-01-01

    The purpose of this study was to determine the potential benefits of combination therapy using dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4) magnetic nanoparticles (MNPs) combined with nontoxic concentration of bortezomib (BTZ) and gambogic acid (GA) on multiple myeloma (MM) RPMI-8226 cells and possible underlying mechanisms. The effects of BTZ-GA-loaded MNP-Fe3O4 (BTZ-GA/MNPs) on cell proliferation were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,4,-diphenyltetrazolium bromide (MTT) method. Cell cycle and apoptosis were detected using the terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling (TUNEL) assay and flow cytometry (FCM). Furthermore, DMSA-Fe3O4 MNPs were characterized in terms of distribution, apoptotic morphology, and cellular uptake by transmission electron microscopy (TEM) and 4,6-diamidino-2-phenylindole (DAPI) staining. Subsequently, the effect of BTZ-GA/MNPs combination on PI3K/Akt activation and apoptotic-related protein were appraised by Western blotting. MTT assay and hematoxylin and eosin (HE) staining were applied to elevate the functions of BTZ-GA/MNPs combination on the tumor xenograft model and tumor necrosis. The results of this study revealed that the majority of MNPs were quasi-spherical and the MNPs taken up by cells were located in the endosome vesicles of cytoplasm. Nontoxic concentration of BTZ-GA/MNPs increased G2/M phase cell cycle arrest and induced apoptosis in RPMI-8226 cells. Furthermore, the combination of BTZ-GA/MNPs activated phosphorylated Akt levels, Caspase-3, and Bax expression, and down-regulated the PI3K and Bcl-2 levels significantly. Meanwhile, the in vivo tumor xenograft model indicated that the treatment of BTZ-GA/MNPs decreased the tumor growth and volume and induced cell apoptosis and necrosis. These findings suggest that chemotherapeutic agents polymerized MNPs-Fe3O4 with GA could serve as a better alternative for targeted therapeutic approaches to treat multiple

  19. Trichloroacetic acid in the vegetation of polluted and remote areas of both hemispheres—Part II: salt lakes as novel sources of natural chlorohydrocarbons

    NASA Astrophysics Data System (ADS)

    Weissflog, Ludwig; Elansky, Nikolai; Putz, Erich; Krueger, Gert; Lange, Christian A.; Lisitzina, Lida; Pfennigsdorff, Andrea

    One of the issues provided for by the 1993 existing substances regulation (793/93/EEC) is the assessment of the environmental risk emanating from waste materials. One such material is the highly volatile substance perchloroethene (PER; TECE). PER is produced in large quantities all over the world by the chemical industry. There are many industrial processes in which PER escapes into the environment, especially the atmosphere. It has since been proven that after entering plants via the air/leaf pathway, airborne PER can be metabolised into the phytotoxic substance trichloroacetic acid. However our own studies detected relatively high levels of TCA in environmental compartments in regions far away from industry which cannot be explained by the anthropogenic input of airborne substances into the relevant ecosystems. This indicates that natural PER emittents also exist and must be identified, in order to find out more about the global spread of PER. This paper reports on the findings of related fieldwork in the Kalmykian Steppe. This area of steppe in southern Russia spans an area extending west-to-east from the Black Sea and the Caspian Sea and north-to-south between the Greater Caucasus and Volgograd. The main aim of the experiments in the Kalmykian Steppe was to study water from lakes, rivers and springs with differing levels of salinity. The concentrations of the chlorinated hydrocarbons (VCHCs) chloroform (CHCl 3), tetrachloromethane (CCl 4), 1,1,1-trichloroethane (1,1,1-C 2H 3Cl 3), trichloroethene (TRI; C 2HCl 3), tetrachloroethene (PER; C 2Cl 4) and TCA in these waters were measured, along with the levels of cations and anions and the pH-value of the waters. The measurements indicate that in particular water from salt lakes located in semiarid/arid areas of the study region must be considered as new types of natural emittents of PER and other chlorinated hydrocarbons as well as trichloroacetic acid. Furthermore, attention is drawn to ecological impacts

  20. Differential effects of deoxycholic acid versus selenium metabolite methylselenol on cell cycle, apoptosis, and MAP kinase pathway in HCT116 human colon cancer cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: A typical part of the Western diet is a high fat intake that leads to increased levels of fecal bile acids, and these bile acids, primarily deoxycholic acid (DCA) in humans, have been believed to be tumor promoters of colon cancer. The cell growth inhibition induced by bile acid deoxyc...

  1. Loss of Mitochondrial Pyruvate Carrier 2 in the Liver Leads to Defects in Gluconeogenesis and Compensation via Pyruvate-Alanine Cycling.

    PubMed

    McCommis, Kyle S; Chen, Zhouji; Fu, Xiaorong; McDonald, William G; Colca, Jerry R; Kletzien, Rolf F; Burgess, Shawn C; Finck, Brian N

    2015-10-01

    Pyruvate transport across the inner mitochondrial membrane is believed to be a prerequisite for gluconeogenesis in hepatocytes, which is important for the maintenance of normoglycemia during prolonged food deprivation but also contributes to hyperglycemia in diabetes. To determine the requirement for mitochondrial pyruvate import in gluconeogenesis, mice with liver-specific deletion of mitochondrial pyruvate carrier 2 (LS-Mpc2(-/-)) were generated. Loss of MPC2 impaired, but did not completely abolish, hepatocyte conversion of labeled pyruvate to TCA cycle intermediates and glucose. Unbiased metabolomic analyses of livers from fasted LS-Mpc2(-/-) mice suggested that alterations in amino acid metabolism, including pyruvate-alanine cycling, might compensate for the loss of MPC2. Indeed, inhibition of pyruvate-alanine transamination further reduced mitochondrial pyruvate metabolism and glucose production by LS-Mpc2(-/-) hepatocytes. These data demonstrate an important role for MPC2 in controlling hepatic gluconeogenesis and illuminate a compensatory mechanism for circumventing a block in mitochondrial pyruvate import. PMID:26344101

  2. Investigations on the "Extreme" Microbial Arsenic Cycle within the Sediments of an Acidic Impoundment of the Former Sulfur Bank Mercury Mine: Herman Pit, Clear Lake, California.

    NASA Astrophysics Data System (ADS)

    Blum, J. S.; Hoeft McCann, S. E.; Bennett, S.; Miller, L. G.; Stoneburner, B.; Saltikov, C.; Oremland, R. S.

    2014-12-01

    The involvement of prokaryotes in the redox reactions of arsenic occurring between this element's +5 [arsenate; As(V)] and + 3 [arsenite; As(III)] oxidation states has been well established. Most research has focused upon circum-neutral pH environments, such as freshwater lake and aquifer sediments, and extreme environments like hot springs and hypersaline soda lakes have also been well investigated. In contrast, little work has been conducted on acidic environments. The azure-hued, clear waters of the Herman Pit are acidic (pH 2-4), and overlie oxidized sediments that have a distinctive red/orange coloration indicative of the presence of ferrihydrites and other Fe(III) minerals. There is extensive ebullitive release of geothermal gases from the lake bottom in the form of numerous continuous-flow seeps which are composed primarily of mixtures of CO2, CH4, and H2S. We collected near-shore surface sediments with an Eckman grab, and stored the "soupy" material in filled mason jars kept at 4˚C. Initial experiments were conducted using 3:1 mixtures of lake water: sediment so as to generate dilute slurries which were amended with mM levels of electron acceptors (arsenate, nitrate, oxygen), electron donors (arsenite, acetate, lactate, hydrogen), and incubated under N2, air, or H2. Owing to the large adsorptive capacity of the Fe(III)-rich slurries, we were unable to detect As(V) or As(III) in the aqueous phase of either live or autoclaved controls, although the former consumed lactate, acetate, nitrate, or hydrogen, while the latter did not. This prompted us to conduct a series of further diluted slurry experiments using the live materials from the first as a 10 % addition to lakewater. In these experiments we observed reduction of As(V) to As(III) in anoxic slurries and that rates were enhanced by addition of electron donors (H2, acetate, or lactate). We also observed oxidation of As(III) to As(V) in oxic slurries and in anoxic slurries amended with nitrate. These

  3. Inhibition of the visual cycle in vivo by 13-cis retinoic acid protects from light damage and provides a mechanism for night blindness in isotretinoin therapy.

    PubMed

    Sieving, P A; Chaudhry, P; Kondo, M; Provenzano, M; Wu, D; Carlson, T J; Bush, R A; Thompson, D A

    2001-02-13

    Isotretinoin (13-cis retinoic acid) is frequently prescribed for severe acne [Peck, G. L., Olsen, T. G., Yoder, F. W., Strauss, J. S., Downing, D. T., Pandya, M., Butkus, D. & Arnaud-Battandier, J. (1979) N. Engl. J. Med. 300, 329-333] but can impair night vision [Fraunfelder, F. T., LaBraico, J. M. & Meyer, S. M. (1985) Am. J. Ophthalmol. 100, 534-537] shortly after the beginning of therapy [Shulman, S. R. (1989) Am. J. Public Health 79, 1565-1568]. As rod photoreceptors are responsible for night vision, we administered isotretinoin to rats to learn whether night blindness resulted from rod cell death or from rod functional impairment. High-dose isotretinoin was given daily for 2 months and produced systemic toxicity, but this caused no histological loss of rod photoreceptors, and rod-driven electroretinogram amplitudes were normal after prolonged dark adaptation. Additional studies showed, however, that even a single dose of isotretinoin slowed the recovery of rod signaling after exposure to an intense bleaching light, and that rhodopsin regeneration was markedly slowed. When only a single dose was given, rod function recovered to normal within several days. Rods and cones both showed slow recovery from bleach after isotretinoin in rats and in mice. HPLC analysis of ocular retinoids after isotretinoin and an intense bleach showed decreased levels of rhodopsin chromophore, 11-cis retinal, and the accumulation of the biosynthetic intermediates, 11-cis and all-trans retinyl esters. Isotretinoin was also found to protect rat photoreceptors from light-induced damage, suggesting that strategies of altering retinoid cycling may have therapeutic implications for some forms of retinal and macular degeneration. PMID:11172037

  4. LRD-22, a novel dual dithiocarbamatic acid ester, inhibits Aurora-A kinase and induces apoptosis and cell cycle arrest in HepG2 cells

    SciTech Connect

    Wang, Huiling; Li, Ridong; Li, Li; Ge, Zemei; Zhou, Rouli; Li, Runtao

    2015-02-27

    In this study we investigated the antitumor activity of the novel dual dithiocarbamatic acid ester LRD-22 in vitro and in vivo. Several cancer cell lines were employed to determine the effect of LRD-22 on cell growth, and the MTT assay showed there was a significant decrease in viable tumor cell numbers in the presence of LRD-22, especially in the HepG2 cell line. Colony formation assay also showed LRD-22 strongly inhibits HepG2 cell growth. Evaluation of the mechanism involved showed that inhibitory effects of LRD-22 on cell growth are due to induction of apoptosis and G2/M arrest. LRD-22 inhibited Aurora-A phosphorylation at Thr{sub 288} and subsequently impaired p53 phosphorylation at Ser{sub 315} which was associated with the proteasome degradation pathway. Tumor suppressor protein p53 is stabilized by this mechanism and accumulates through inhibition of Aurora-A kinase activity via treatment with LRD-22. In vivo study of HepG2 xenograft in nude mice also shows LRD-22 suppresses tumor growth at a concentration of 5 mg/kg without animals suffering loss of body weight. In conclusion, our results demonstrate LRD-22 acts as an Aurora-A kinase inhibitor to induce apoptosis and inhibit proliferation in HepG2 cells, and should be considered as a promising targeting agent for HCC therapy. - Highlights: • LRD-22 significantly inhibits cancer cell growth, especially in the HepG2 cell line. • The inhibitory effect of LRD-22 is due to induction of apoptosis and cell cycle arrest. • LRD-22 inhibits Aurora-A phosphorylation which results in subsequent impairment of the p53 pathway. • LRD-22 suppresses tumor growth in xenograft mice without body weight loss.

  5. CypD−/− Hearts HaveAltered Levels of Proteins Involved in Krebs Cycle, Branch Chain Amino Acid Degradation and Pyruvate Metabolism

    PubMed Central

    Menazza, Sara; Wong, Renee; Nguyen, Tiffany; Wang, Guanghui; Gucek, Marjan; Murphy, Elizabeth

    2013-01-01

    Cyclophilin D (CypD) is a mitochondrial chaperone that has been shown to regulate the mitochondrial permeability transition pore (MPTP). MPTP opening is a major determinant of mitochondrial dysfunction and cardiomyocyte death during ischemia/reperfusion (I/R) injury. Mice lacking CypD have been widely used to study regulation of the MPTP, and it has been shown recently that genetic depletion of CypD correlates with elevated levels of mitochondrial Ca2+. The present study aimed to characterize the metabolic changes in CypD−/− hearts. Initially, we used a proteomics approach to examine protein changes in CypD−/− mice. Using pathway analysis we found that CypD−/− hearts have alteration in branched chain amino acid metabolism, pyruvate metabolism and the Krebs cycle. We tested whether these metabolic changes were due to inhibition of electron transfer from these metabolic pathways into the electron transport chain. As we found decreased levels of succinate dehydrogenase and electron transfer flavoprotein in the proteomics analysis, we examined whether activities of these enzymes might be altered. However, we found no alterations in their activities. The proteomics study also showed a 23% decrease in carnitine -palmitoyltransferase 1 (CPT1), which prompted us to perform a metabolomics analysis. Consistent with the decrease in CPT1, we found a significant decrease in C4/Ci4, C5-OH/C3-DC, C12:1, C14:1, C16:1, and C20:3 acyl carnitines in hearts from CypD−/− mice. In summary, CypD−/− hearts exhibit changes in many metabolic pathways and caution should be used when interpreting results from these mice as due solely to inhibition of the MPTP. PMID:23262437

  6. State estimation of an acid gas removal (AGR) plant as part of an integrated gasification combined cycle (IGCC) plant with CO2 capture

    SciTech Connect

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    An accurate estimation of process state variables not only can increase the effectiveness and reliability of process measurement technology, but can also enhance plant efficiency, improve control system performance, and increase plant availability. Future integrated gasification combined cycle (IGCC) power plants with CO2 capture will have to satisfy stricter operational and environmental constraints. To operate the IGCC plant without violating stringent environmental emission standards requires accurate estimation of the relevant process state variables, outputs, and disturbances. Unfortunately, a number of these process variables cannot be measured at all, while some of them can be measured, but with low precision, low reliability, or low signal-to-noise ratio. As a result, accurate estimation of the process variables is of great importance to avoid the inherent difficulties associated with the inaccuracy of the data. Motivated by this, the current paper focuses on the state estimation of an acid gas removal (AGR) process as part of an IGCC plant with CO2 capture. This process has extensive heat and mass integration and therefore is very suitable for testing the efficiency of the designed estimators in the presence of complex interactions between process variables. The traditional Kalman filter (KF) (Kalman, 1960) algorithm has been used as a state estimator which resembles that of a predictor-corrector algorithm for solving numerical problems. In traditional KF implementation, good guesses for the process noise covariance matrix (Q) and the measurement noise covariance matrix (R) are required to obtain satisfactory filter performance. However, in the real world, these matrices are unknown and it is difficult to generate good guesses for them. In this paper, use of an adaptive KF will be presented that adapts Q and R at every time step of the algorithm. Results show that very accurate estimations of the desired process states, outputs or disturbances can be

  7. Valproic acid inhibits proliferation of HER2-expressing breast cancer cells by inducing cell cycle arrest and apoptosis through Hsp70 acetylation

    PubMed Central

    MAWATARI, TOSHIKI; NINOMIYA, ITASU; INOKUCHI, MASAFUMI; HARADA, SHINICHI; HAYASHI, HIRONORI; OYAMA, KATSUNOBU; MAKINO, ISAMU; NAKAGAWARA, HISATOSHI; MIYASHITA, TOMOHARU; TAJIMA, HIDEHIRO; TAKAMURA, HIROYUKI; FUSHIDA, SACHIO; OHTA, TETSUO

    2015-01-01

    Breast cancer encompasses a heterogeneous group of diseases at the molecular level. It is known that chemo-sensitivity of breast cancer depends on its molecular subtype. We investigated the growth inhibitory effect of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, and the mechanism of this inhibition on four breast cancer cell lines with different molecular subtypes. The growth inhibitory effect of VPA in the four different breast cancer cell lines was investigated. The alteration of levels of p21 WAF1, cleaved caspase-3, acetylated Heat shock protein (Hsp) 90, acetylated Hsp70, and acetylated α-tubulin by VPA was examined in VPA-sensitive, human epidermal receptor 2 (HER2)-overexpressing SKBR3 cells. The cell growth inhibition of breast cancer cell lines was dependent on the dose and exposure time of VPA. The cell growth of HER2-overexpressing SKBR3 cell line was inhibited by VPA to a much greater degree than other cell lines studied. In SKBR3 cell line, VPA upregulated expression of p21 WAF1 and cleaved caspase-3 in the early phase. VPA markedly increased Hsp70 acetylation in a time-dependent manner but did not increase Hsp90 acetylation. Our data demonstrated that VPA inhibited cell proliferation and induced cell cycle arrest and apoptosis of HER2-overexpressing breast cancer cells. This anti-proliferation effect might be the direct function of VPA as an HDAC inhibitor. We propose an alternative mechanism whereby acetylation of Hsp70 disrupts the function of Hsp90 and leads to downregulation of its client proteins, including HER2 that might be the indirect function of VPA, in the sense that non-histone proteins are acetylated. PMID:26497673

  8. THE COMPARISON BETWEEN TRICHLOROACETIC ACID 50% AND CO2 LASER IN THE TREATMENT OF CUTANEOUS LEISHMANIASIS SCAR

    PubMed Central

    Nilforoushzadeh, Mohammad Ali; Jaffary, Fariba; Ansari, Nazli; Moradi, Shahram; Siadat, Amir Hossein

    2011-01-01

    Background: The scars of the cutaneous leishmaniasis and psychological problems of this disease need different interventions for its correction. Aim: Our objective in this study was to compare the efficacy of 50% trichloroacetic acid (TCA) solution and CO2 laser for treatment of the atrophic scars due to leishmaniasis. Materials and Methods: This was a randomized clinical trial performed in 92 patients. Patients were randomized into two groups: the first group was treated with 50% TCA solution, once monthly and for a maximum of 5 months, and the second group was treated with CO2 laser which was performed for only one time. Patients were followed-up at 3 and 6 months after starting the treatment. The improvement of scar was graded by a 6-point scale using digital camera and the collected data were analyzed using SPSS software. Results: In this study, 74 females and 18 males were enrolled. The improvement of scar was 48.13% in the TCA group and 44.87% in the CO2 laser group. This difference was not statically significant (P = 0.55). There was also no significant difference regarding side effects between these two groups. Conclusion: The results of our study showed that efficacy of focal with 50% TCA solution is compared with CO2 laser in treatment of leishmaniasis scar. Because of the low cost and simple application of TCA solution in comparison with CO2 laser, we suggest use of this treatment for correction of leishmaniasis scar or the atrophic scars. PMID:21716542

  9. Dynamics and regulation of glycolysis-tricarboxylic acid metabolism in the midgut of Spodoptera litura during metamorphosis.

    PubMed

    Hu, D; Luo, W; Fan, L F; Liu, F L; Gu, J; Deng, H M; Zhang, C; Huang, L H; Feng, Q L

    2016-04-01

    Significant changes usually take place in the internal metabolism of insects during metamorphosis. The glycolysis-tricarboxylic acid (glycolysis-TCA) pathway is important for energy metabolism. To elucidate its dynamics, the mRNA levels of genes involved in this pathway were examined in the midgut of Spodoptera litura during metamorphosis, and the pyruvate content was quantified. The expression patterns of these genes in response to starvation were examined, and the interaction between protein phosphatase 1 (PP1) and phosphofructokinase (PFK) was studied. The results revealed that the expression or activities of most glycolytic enzymes was down-regulated in prepupae and then recovered in some degree in pupae, and all TCA-related genes were remarkably suppressed in both the prepupae and pupae. Pyruvate was enriched in the pupal midgut. Taken together, these results suggest that insects decrease both glycolysis and TCA in prepupae to save energy and then up-regulate glycolysis but down-regulate TCA in pupae to increase the supply of intermediates for construction of new organs. The expression of all these genes were down-regulated by starvation, indicating that non-feeding during metamorphosis may be a regulator of glycolysis-TCA pathway in the midgut. Importantly, interaction between PP1 and PFK was identified and is suggested to be involved in the regulation of glycolysis. PMID:26683413

  10. A medium-chain fatty acid as an alternative energy source in mouse preimplantation development

    PubMed Central

    Yamada, Mitsutoshi; Takanashi, Kazumi; Hamatani, Toshio; Hirayama, Akiyoshi; Akutsu, Hidenori; Fukunaga, Tomoko; Ogawa, Seiji; Sugawara, Kana; Shinoda, Kosaku; Soga, Tomoyoshi; Umezawa, Akihiro; Kuji, Naoaki; Yoshimura, Yasunori; Tomita, Masaru

    2012-01-01

    To further optimize the culturing of preimplantation embryos, we undertook metabolomic analysis of relevant culture media using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). We detected 28 metabolites: 23 embryo-excreted metabolites including 16 amino acids and 5 media-derived metabolites (e.g., octanoate, a medium-chain fatty acid (MCFA)). Due to the lack of information on MCFAs in mammalian preimplantation development, this study examined octanoate as a potential alternative energy source for preimplantation embryo cultures. No embryos survived in culture media lacking FAs, pyruvate, and glucose, but supplementation of octanoate rescued the embryonic development. Immunoblotting showed significant expression of acyl-CoA dehydrogenase and hydroxyacyl-CoA dehydrogenase, important enzymes for ß-oxidation of MCFAs, in preimplantation embryo. Furthermore, CE-TOFMS traced [1-13C8] octanoate added to the culture media into intermediate metabolites of the TCA cycle via ß-oxidation in mitochondria. These results are the first demonstration that octanoate could provide an efficient alternative energy source throughout preimplantation development. PMID:23226596

  11. Serum Bile Acids Are Associated with Pathological Progression of Hepatitis B-Induced Cirrhosis.

    PubMed

    Wang, Xiaoning; Xie, Guoxiang; Zhao, Aihua; Zheng, Xiaojiao; Huang, Fengjie; Wang, Yixing; Yao, Chun; Jia, Wei; Liu, Ping

    2016-04-01

    Recent metabonomic studies have identified an important role of bile acids in patients with liver cirrhosis. Serum bile acids, such as glycocholate (GCA), glycochenodeoxycholate (GCDCA), taurocholate (TCA), and taurochenodeoxycholate (TCDCA), increased significantly in liver cirrhosis patients. Our recently published urinary metabonomic study showed that glycocholate 3-glucuronide, taurohyocholate, TCA, glycolithocholate 3-sulfate, and glycoursodeoxycholate (GUDCA) were markedly increased in hepatitis B-induced cirrhotic patients (n = 63) compared with healthy controls (n = 31). The urinary levels of GUDCA were able to differentiate among three stages of cirrhotic patients with Child-Pugh (CP) score A, B, and C. In this study, we recruited two new cohorts of patients with hepatitis-B-induced cirrhosis and healthy control subjects and quantitatively profiled their serum bile acids using ultra-performance liquid chromatography triple quadrupole mass spectrometry. Serum bile acid profile and corresponding differential bile acids were characterized, in addition to the blood routine, liver, and renal function tests. The alterations of bile acids contributing to the intergroup variation between healthy controls and cirrhotic patients and among pathological stages of CP grade A, B and C were also investigated. Five bile acids, GCA, GCDCA, TCA, TCDCA, and GUDCA, were significantly altered among different stages of liver cirrhosis (n = 85), which was validated with an independent cohort of cirrhotic patients (n = 53). Our results show that dynamic alteration of serum bile acids is indicative of an exacerbated liver function, highlighting their potential as biomarkers for staging the liver cirrhosis and monitoring its progression. PMID:25964117

  12. Thermus oshimai JL-2 and T. thermophilus JL-18 genome analysis illuminates pathways for carbon, nitrogen, and sulfur cycling

    PubMed Central

    Murugapiran, Senthil K.; Huntemann, Marcel; Wei, Chia-Lin; Han, James; Detter, J. C.; Han, Cliff; Erkkila, Tracy H.; Teshima, Hazuki; Chen, Amy; Kyrpides, Nikos; Mavrommatis, Konstantinos; Markowitz, Victor; Szeto, Ernest; Ivanova, Natalia; Pagani, Ioanna; Pati, Amrita; Goodwin, Lynne; Peters, Lin; Pitluck, Sam; Lam, Jenny; McDonald, Austin I.; Dodsworth, Jeremy A.; Woyke, Tanja; Hedlund, Brian P.

    2013-01-01

    The complete genomes of Thermus oshimai JL-2 and T. thermophilus JL-18 each consist of a circular chromosome, 2.07 Mb and 1.9 Mb, respectively, and two plasmids ranging from 0.27 Mb to 57.2 kb. Comparison of the T. thermophilus JL-18 chromosome with those from other strains of T. thermophilus revealed a high degree of synteny, whereas the megaplasmids from the same strains were highly plastic. The T. oshimai JL-2 chromosome and megaplasmids shared little or no synteny with other sequenced Thermus strains. Phylogenomic analyses using a concatenated set of conserved proteins confirmed the phylogenetic and taxonomic assignments based on 16S rRNA phylogenetics. Both chromosomes encode a complete glycolysis, tricarboxylic acid (TCA) cycle, and pentose phosphate pathway plus glucosidases, glycosidases, proteases, and peptidases, highlighting highly versatile heterotrophic capabilities. Megaplasmids of both strains contained a gene cluster encoding enzymes predicted to catalyze the sequential reduction of nitrate to nitrous oxide; however, the nitrous oxide reductase required for the terminal step in denitrification was absent, consistent with their incomplete denitrification phenotypes. A sox gene cluster was identified in both chromosomes, suggesting a mode of chemolithotrophy. In addition, nrf and psr gene clusters in T. oshmai JL-2 suggest respiratory nitrite ammonification and polysulfide reduction as possible modes of anaerobic respiration. PMID:24019992

  13. Effects of nicotine on cellular proliferation, macromolecular synthesis and cell cycle phase distribution in human and murine cells

    SciTech Connect

    Konno, S.; Chiao, J.; Rossi, J.; Wang, C.H.; Wu, J.M.

    1986-05-01

    Addition of nicotine causes a dose- and time-dependent inhibition of cell growth in established human and murine cells. In the human promyelocytic HL-60 leukemic cells, 3 mM nicotine results in a 50% inhibition of cellular proliferation after 80 h. Nicotine was also found to affect the cell cycle distribution of HL-60 cells. Treatment with 4 mM nicotine for 20 h causes an increase in proportion of Gl-phase cells (from 49% to 57%) and a significant decrease in the proportion of S-phase cells (from 41% to 32%). These results suggest that nicotine causes cell arrest in the Gl-phase which may in part account for its effects on cell growth. To determine whether nicotine has a primary effect on the uptake/transport of macromolecular precursors into cells, HL-60 cells were treated with 2-6 mM nicotine for 30 h/sub 3/ at the end of which time cells were labeled with (/sup 3/H)thymidine, (/sup 3/H)uridine, (/sup 14/C)lysine and (/sup 35/S)methionine, the trichloroacetic acid (TCA) soluble and insoluble radioactivities from each of the labeling conditions were determined. These studies show that nicotine primarily affect the synthesis of proteins.

  14. Performance improvement of GaN-based metal-semiconductor-metal photodiodes grown on Si(111) substrate by thermal cycle annealing process

    NASA Astrophysics Data System (ADS)

    Lin, Jyun-Hao; Huang, Shyh-Jer; Su, Yan-Kuin

    2014-01-01

    A simple thermal cycle annealing (TCA) process was used to improve the quality of GaN grown on a Si substrate. The X-ray diffraction (XRD) and etch pit density (EPD) results revealed that using more process cycles, the defect density cannot be further reduced. However, the performance of GaN-based metal-semiconductor-metal (MSM) photodiodes (PDs) prepared on Si substrates showed significant improvement. With a two-cycle TCA process, it is found that the dark current of the device was only 1.46 × 10-11 A, and the photo-to-dark-current contrast ratio was about 1.33 × 105 at 5 V. Also, the UV/visible rejection ratios can reach as high as 1077.

  15. Characterization of lead (Ⅱ)-containing activated carbon and its excellent performance of extending lead-acid battery cycle life for high-rate partial-state-of-charge operation

    NASA Astrophysics Data System (ADS)

    Tong, Pengyang; Zhao, Ruirui; Zhang, Rongbo; Yi, Fenyun; Shi, Guang; Li, Aiju; Chen, Hongyu

    2015-07-01

    In this work, lead (Ⅱ)-containing activated carbon (Pb@C) is prepared as the additive of negative active mass (NAM), aiming to enhance the electrochemical characteristics of the lead-acid battery. The characters of the Pb@C materials and their electrochemical properties are characterized by XRD, SEM, back-scattering electron image (BESI) and electrochemical methods. The lead (Ⅱ) ions disperse well in the carbon bulk of the obtained Pb@C materials as observed, and these materials exhibit remarkable higher specific capacitance and higher hydrogen evolution over-potential compared with original carbons. Many 2 V lead-acid batteries are assembled manually in our lab, and then the batteries are disassembled after formation and high-rate-partial-state-of-charge (HRPSoC) cycling. Results manifest that the Pb@C additives exhibit high affinity to lead and act as a porous-skeleton in the formation process as well as under HRPSoC cycling conditions, leading to the small and fine formation of PbSO4 particles and accordingly higher active material utilization rate more than 50%, better cycling performance and charging acceptance. Besides, excellent cycle performances of these batteries have great relationship with the dazzling hydrogen evolution performance of Pb@C materials. A possible working mechanism is also proposed based on the testing data in this paper.

  16. Fragile cycles

    NASA Astrophysics Data System (ADS)

    Bonatti, Ch.; Díaz, L. J.

    We study diffeomorphisms f with heterodimensional cycles, that is, heteroclinic cycles associated to saddles p and q with different indices. Such a cycle is called fragile if there is no diffeomorphism close to f with a robust cycle associated to hyperbolic sets containing the continuations of p and q. We construct a codimension one submanifold of Diff(S×S) that consists of diffeomorphisms with fragile heterodimensional cycles. Our construction holds for any manifold of dimension ⩾4.

  17. Fructose Alters Intermediary Metabolism of Glucose in Human Adipocytes and Diverts Glucose to Serine Oxidation in the One–Carbon Cycle Energy Producing Pathway

    PubMed Central

    Varma, Vijayalakshmi; Boros, László G.; Nolen, Greg T.; Chang, Ching-Wei; Wabitsch, Martin; Beger, Richard D.; Kaput, Jim

    2015-01-01

    Increased consumption of sugar and fructose as sweeteners has resulted in the utilization of fructose as an alternative metabolic fuel that may compete with glucose and alter its metabolism. To explore this, human Simpson-Golabi-Behmel Syndrome (SGBS) preadipocytes were differentiated to adipocytes in the presence of 0, 1, 2.5, 5 or 10 mM of fructose added to a medium containing 5 mM of glucose representing the normal blood glucose concentration. Targeted tracer [1,2-13C2]-d-glucose fate association approach was employed to examine the influence of fructose on the intermediary metabolism of glucose. Increasing concentrations of fructose robustly increased the oxidation of [1,2-13C2]-d-glucose to 13CO2 (p < 0.000001). However, glucose-derived 13CO2 negatively correlated with 13C labeled glutamate, 13C palmitate, and M+1 labeled lactate. These are strong markers of limited tricarboxylic acid (TCA) cycle, fatty acid synthesis, pentose cycle fluxes, substrate turnover and NAD+/NADP+ or ATP production from glucose via complete oxidation, indicating diminished mitochondrial energy metabolism. Contrarily, a positive correlation was observed between glucose-derived 13CO2 formed and 13C oleate and doses of fructose which indicate the elongation and desaturation of palmitate to oleate for storage. Collectively, these results suggest that fructose preferentially drives glucose through serine oxidation glycine cleavage (SOGC pathway) one-carbon cycle for NAD+/NADP+ production that is utilized in fructose-induced lipogenesis and storage in adipocytes. PMID:26087138

  18. Conjugated bile acids activate the sphingosine-1-phosphate receptor 2 in primary rodent hepatocytes.

    PubMed

    Studer, Elaine; Zhou, Xiqiao; Zhao, Renping; Wang, Yun; Takabe, Kazuaki; Nagahashi, Masayuki; Pandak, William M; Dent, Paul; Spiegel, Sarah; Shi, Ruihua; Xu, Weiren; Liu, Xuyuan; Bohdan, Pat; Zhang, Luyong; Zhou, Huiping; Hylemon, Phillip B

    2012-01-01

    Bile acids have been shown to be important regulatory molecules for cells in the liver and gastrointestinal tract. They can activate various cell signaling pathways including extracellular regulated kinase (ERK)1/2 and protein kinase B (AKT) as well as the G-protein-coupled receptor (GPCR) membrane-type bile acid receptor (TGR5/M-BAR). Activation of the ERK1/2 and AKT signaling pathways by conjugated bile acids has been reported to be sensitive to pertussis toxin (PTX) and dominant-negative Gα(i) in primary rodent hepatocytes. However, the GPCRs responsible for activation of these pathways have not been identified. Screening GPCRs in the lipid-activated phylogenetic family (expressed in HEK293 cells) identified sphingosine-1-phosphate receptor 2 (S1P(2) ) as being activated by taurocholate (TCA). TCA, taurodeoxycholic acid (TDCA), tauroursodeoxycholic acid (TUDCA), glycocholic acid (GCA), glycodeoxycholic acid (GDCA), and S1P-induced activation of ERK1/2 and AKT were significantly inhibited by JTE-013, a S1P(2) antagonist, in primary rat hepatocytes. JTE-013 significantly inhibited hepatic ERK1/2 and AKT activation as well as short heterodimeric partner (SHP) mRNA induction by TCA in the chronic bile fistula rat. Knockdown of the expression of S1P(2) by a recombinant lentivirus encoding S1P(2) shRNA markedly inhibited the activation of ERK1/2 and AKT by TCA and S1P in rat primary hepatocytes. Primary hepatocytes prepared from S1P(2) knock out (S1P(2) (-/-) ) mice were significantly blunted in the activation of the ERK1/2 and AKT pathways by TCA. Structural modeling of the S1P receptors indicated that only S1P(2) can accommodate TCA binding. In summary, all these data support the hypothesis that conjugated bile acids activate the ERK1/2 and AKT signaling pathways primarily through S1P(2) in primary rodent hepatocytes. PMID:21932398

  19. Evaluation of the environmental implications of the incorporation of feed-use amino acids in the manufacturing of pig and broiler feeds using Life Cycle Assessment.

    PubMed

    Mosnier, E; van der Werf, H M G; Boissy, J; Dourmad, J-Y

    2011-12-01

    The incorporation of feed-use (FU) amino acids (AAs) in diets results in a reduced use of protein-rich ingredients such as soybean meal, recognized to have elevated contributions to environmental impacts. This study investigated whether the incorporation of L-lysine.HCl, L-threonine and FU-methionine reduces the environmental impacts of pig and broiler feeds using Life Cycle Assessment. The following impact categories were considered: climate change, eutrophication, acidification, terrestrial ecotoxicity, cumulative energy demand and land occupation. Several feeds were formulated either to minimize the cost of the formulation (with or without AA utilization), to maximize AA incorporation (i.e. the cost of AA was considered to be similar to that of soybean meal), or to minimize greenhouse gas emissions. For both pig and broiler feeds, calculations were made first using only cereals and soybean meal as main ingredients and then using cereals and several protein-rich ingredients (soybean meal, rapeseed meal and peas). In addition, these calculations were performed using two types of soybean meal (from Brazil, associated with recent deforestation or not). For broiler feeds, two types of maize (from France, irrigated, with mineral fertilization v. not irrigated, with animal manure fertilization) were also tested. Regarding the feeds formulated to minimize cost, incorporation of AA decreased the values for eutrophication, terrestrial ecotoxicity and cumulative energy demand of both pig and broiler feeds, regardless of the base ingredients. Reduction in climate change and acidification due to the incorporation of AA depended on the nature of the feed ingredients, with the effect of AA incorporation being greater when combined with ingredients with high impacts such as soybean meal associated with deforestation. Feeds formulated to maximize AA incorporation generally had a similar composition to those formulated to minimize cost, suggesting that the costs of AA were not

  20. Altered secretion of selected arachidonic acid metabolites during subclinical endometritis relative to estrous cycle stage and grade of fibrosis in mares.

    PubMed

    Gajos, Katarzyna; Kozdrowski, Roland; Nowak, Marcin; Siemieniuch, Marta J

    2015-08-01

    Mares that fail to become pregnant after repeated breeding, without showing typical signs of clinical endometritis, should be suspected of subclinical endometritis (SE). Contact with infectious agents results in altered synthesis and secretion of inflammatory mediators, including cytokines and arachidonic acid metabolites, and disturbs endometrial functional balance. To address the hypothesis that SE affects the immune endocrine status of the equine endometrium, spontaneous secretion of prostaglandin E(2) (PGE(2)), prostaglandin F(2α) (PGF(2α)), 6-keto-PGF(1α )(a metabolite of prostacyclin I(2)), leukotriene B(4) (LTB(4)), and leukotriene C(4) (LTC(4)) was examined. In addition, secretion of these factors was examined relative to the grade of inflammation, fibrosis, and estrous cycle stage. Eighty-two warmblood mares, of known breeding history, were enrolled in this study. On the basis of histopathologic assessment, mares were classified as suffering from first-grade SE, second-grade SE, or being healthy. The grade of fibrosis and the infiltration of endometrial tissue with polymorphonuclear leukocytes were examined by routine hematoxylin-eosin staining. In mares suffering from SE, the secretion profiles of PGE(2), 6-keto-PGF(1α), LTB(4), and LTC(4) were changed compared to mares that did not suffer from endometritis. The secretion of PGE(2) and 6-keto-PGF1α was increased, whereas that of LTB(4) and LTC(4) was decreased. Secretion of 6-keto-PGF(1α) was increased in first- and second-grade SE (P < 0.01). The concentration of PGI(2) metabolite was increased only in inflamed endometrium, independently of the inflammation grade, but was not affected by fibrosis. Prostaglandin E(2) secretion was increased in second-grade SE (P < 0.05). The secretion of LTB(4) decreased in both first- and second-grade SE (P < 0.05), whereas secretion of LTC(4) was decreased only in second-grade SE (P < 0.05). Fibrosis did not change the secretion profile of PGE(2), PGF(2α), and 6

  1. Sensor placement algorithm development to maximize the efficiency of acid gas removal unit for integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture

    SciTech Connect

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future integrated gasification combined cycle (IGCC) power plants with CO{sub 2} capture will face stricter operational and environmental constraints. Accurate values of relevant states/outputs/disturbances are needed to satisfy these constraints and to maximize the operational efficiency. Unfortunately, a number of these process variables cannot be measured while a number of them can be measured, but have low precision, reliability, or signal-to-noise ratio. In this work, a sensor placement (SP) algorithm is developed for optimal selection of sensor location, number, and type that can maximize the plant efficiency and result in a desired precision of the relevant measured/unmeasured states. In this work, an SP algorithm is developed for an selective, dual-stage Selexol-based acid gas removal (AGR) unit for an IGCC plant with pre-combustion CO{sub 2} capture. A comprehensive nonlinear dynamic model of the AGR unit is developed in Aspen Plus Dynamics® (APD) and used to generate a linear state-space model that is used in the SP algorithm. The SP algorithm is developed with the assumption that an optimal Kalman filter will be implemented in the plant for state and disturbance estimation. The algorithm is developed assuming steady-state Kalman filtering and steady-state operation of the plant. The control system is considered to operate based on the estimated states and thereby, captures the effects of the SP algorithm on the overall plant efficiency. The optimization problem is solved by Genetic Algorithm (GA) considering both linear and nonlinear equality and inequality constraints. Due to the very large number of candidate sets available for sensor placement and because of the long time that it takes to solve the constrained optimization problem that includes more than 1000 states, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel

  2. Code Calibration Applied to the TCA High-Lift Model in the 14 x 22 Wind Tunnel (Simulation With and Without Model Post-Mount)

    NASA Technical Reports Server (NTRS)

    Lessard, Wendy B.

    1999-01-01

    The objective of this study is to calibrate a Navier-Stokes code for the TCA (30/10) baseline configuration (partial span leading edge flaps were deflected at 30 degs. and all the trailing edge flaps were deflected at 10 degs). The computational results for several angles of attack are compared with experimental force, moments, and surface pressures. The code used in this study is CFL3D; mesh sequencing and multi-grid were used to full advantage to accelerate convergence. A multi-grid approach was used similar to that used for the Reference H configuration allowing point-to-point matching across all the trailingedge block interfaces. From past experiences with the Reference H (ie, good force, moment, and pressure comparisons were obtained), it was assumed that the mounting system would produce small effects; hence, it was not initially modeled. However, comparisons of lower surface pressures indicated the post mount significantly influenced the lower surface pressures, so the post geometry was inserted into the existing grid using Chimera (overset grids).

  3. Transformation of cinnamic acid from trans- to cis-form raises a notable bactericidal and synergistic activity against multiple-drug resistant Mycobacterium tuberculosis.

    PubMed

    Chen, Yen-Ling; Huang, Shao-Tsung; Sun, Fang-Ming; Chiang, Yu-Ling; Chiang, Chia-Jung; Tsai, Chiung-Man; Weng, Chia-Jui

    2011-06-14

    Tuberculosis (TB) is a contagious disease caused by Mycobacterium tuberculosis. The long course of treatments on TB with a combination of antibiotics leads unfavorable side effects and poor patient compliance which contributes to sustaining multiple-drug resistant tuberculosis (MDR-TB). Therefore, the development of a new effective drug or synergist to reduce the prevalence of MDR-TB is urgent to date. Cinnamic acid (CA) is a natural occurring phenolic compound with anti-microbial activity. Both trans- and cis-isoforms of CA exist in planta, and cis-cinnamic acid (c-CA) can be transformed from trans-cinnamic acid (t-CA) under sunlight. Due to the unavailability of c-CA, the literature regarding the biological functions of c-CA is still limited. We had previously developed a practicable method for the transformation of c-CA from t-CA and the isolation of c-CA. Using the techniques, sufficient c-CA was obtained to evaluate its antituberculosis activity against a MDR M. tuberculosis strain. Moreover, the synergistic effects of c-CA and t-CA with two first-line anti-TB antibiotics, isoniazid (INH) and rifampicin (RIF), were also determined. Although both of c-CA and t-CA decreased the viability of MDR-TB bacilli in a dose-dependent manner, the antituberculosis activity of c-CA was approximately 120-fold of t-CA. Furthermore, the c-CA exhibited higher synergistic effect with INH or RIF against tuberculosis than t-CA. The micrographs of scanning electron microscope (SEM) display that c-CA caused an injury on the out-layer of MDR-TB bacilli. The c-CA might be a potential anti-mycobacterial or synergistic agent that can be developed to against tuberculosis. PMID:21536127

  4. Self-organizing biochemical cycles

    NASA Technical Reports Server (NTRS)

    Orgel, L. E.; Bada, J. L. (Principal Investigator)

    2000-01-01

    I examine the plausibility of theories that postulate the development of complex chemical organization without requiring the replication of genetic polymers such as RNA. One conclusion is that theories that involve the organization of complex, small-molecule metabolic cycles such as the reductive citric acid cycle on mineral surfaces make unreasonable assumptions about the catalytic properties of minerals and the ability of minerals to organize sequences of disparate reactions. Another conclusion is that data in the Beilstein Handbook of Organic Chemistry that have been claimed to support the hypothesis that the reductive citric acid cycle originated as a self-organized cycle can more plausibly be interpreted in a different way.

  5. Menstrual Cycle

    MedlinePlus

    ... Pregnancy This information in Spanish ( en español ) The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  6. A Comparison between the Effects of Glucantime, Topical Trichloroacetic Acid 50% plus Glucantime, and Fractional Carbon Dioxide Laser plus Glucantime on Cutaneous Leishmaniasis Lesions

    PubMed Central

    Jaffary, Fariba; Nilforoushzadeh, Mohammad Ali; Siadat, Amirhossein; Haftbaradaran, Elaheh; Ansari, Nazli; Ahmadi, Elham

    2016-01-01

    Background. Cutaneous leishmaniasis is an endemic disease in Iran. Pentavalent antimonial drugs have been the first line of therapy in cutaneous leishmaniasis for many years. However, the cure rate of these agents is still not favorable. This study was carried out to compare the efficacies of intralesional glucantime with topical trichloroacetic acid 50% (TCA 50%) + glucantime and fractional carbon dioxide laser + glucantime in the treatment of cutaneous leishmaniasis. Methods. A total of 90 patients were randomly divided into three groups of 30 to be treated with intralesional injection of glucantime, a combination of topical TCA 50% and glucantime, or a combination of fractional laser and glucantime. The overall clinical improvement and changes in sizes of lesions and scars were assessed and compared among three groups. Results. The mean duration of treatment was 6.1 ± 2.1 weeks in all patients (range: 2–12 weeks) and 6.8 ± 1.7, 5.2 ± 1.0, and 6.3 ± 3.0 weeks in glucantime, topical TCA plus glucantime, and fractional laser plus glucantime groups, respectively (P = 0.011). Complete improvement was observed in 10 (38.5%), 27 (90%), and 20 (87%) patients of glucantime, glucantime + TCA, and glucantime + laser groups, respectively (P < 0.001). Conclusion. Compared to glucantime alone, the combination of intralesional glucantime and TCA 50% or fractional CO2 laser had significantly higher and faster cure rate in patients with cutaneous leishmaniasis. PMID:27148363

  7. Inflammation and Resolution Are Associated with Upregulation of Fatty Acid β-Oxidation in Zymosan-Induced Peritonitis

    PubMed Central

    Fujieda, Yusuke; Manno, Atsushi; Hayashi, Yasuhiro; Rhodes, Nelson; Guo, Lining; Arita, Makoto; Bamba, Takeshi; Fukusaki, Eiichiro

    2013-01-01

    Inflammation is a fundamental defensive response to harmful stimuli. However, it can cause damage if it does not subside. To avoid such damage, organisms have developed a mechanism called resolution of inflammation. Here we applied an untargeted metabolomics approach to a sterile and self-resolving animal model of acute inflammation, namely zymosan-induced peritonitis in mice, to examine the effect of inflammation and resolution on the metabolomic profiles. Significant and time-dependent changes in metabolite profiles after zymosan administration were observed in both peritoneal wash fluid (PWF) and plasma. These metabolomic changes correlated well with inflammatory chemokine or cytokine production. In PWF, most of metabolites that could detected increased in zymosan-treated mice, which is suggestive of inflammation, oxidative stress and increased energy demands. In plasma, most metabolites in the central metabolic pathway (glycolysis and TCA cycle) were significantly downregulated after zymosan administration. The concentration of the ketone body 3-hydroxybutyric acid (3-HB) in plasma and PWF increased in zymosan-injected animals indicating upregulation of fatty acid β-oxidation. Increased 3-HB level was observed in the cells that infiltrated into the peritoneal cavity and these infiltrated cells might contribute, at least in part, to the production of 3-HB in the peritoneal cavity. PMID:23776651

  8. Carbon and nitrogen cycling in thermally heated sediments

    NASA Astrophysics Data System (ADS)

    Meyer-Dombard, D. R.; Burton, M.; Vennelakanti, S.; Havig, J. R.; Shock, E.

    2009-12-01

    Hydrothermally heated sediment environments, such as are found in abundance throughout Yellowstone National Park, host fully functional microbial ecosystems. As with any ecosystem, both sources and sinks of carbon, nitrogen, and a myriad of other nutrients and energy-driving factors must be supplied. While we know microbial communities in hydrothermal environments can be surprisingly diverse, we know little about basic ecological functions such as carbon and nitrogen cycling. Previous work has shown that carbon cycling in one hot spring in Yellowstone National Park [“Bison Pool”] and its associated runoff channel functions as a complex system. Analysis of carbon and nitrogen isotopes in sediments and biofilms across a temperature and chemical gradient at this location revealed that the four best studied carbon fixation pathways [Calvin, reverse tricarboxylic acid, acetyl-CoA, 3-hydroxypropionate cycles] may all be functioning in this system, and nitrogen fixation varies across the chemosynthetic/photosynthetic ecotone [1]. Microcosm experiments using biofilms from this hot spring as inoculae with 13C labeled carbon substrates indicate heterotrophic growth [2]. In addition, metagenomic analysis of environmental DNA has indicated the presence of genes involved in carbon fixation [both phototrophic and autotrophic], and heterotrophy, as well as nitrogen fixation [3]. Studies from other Yellowstone locations have also found genetic evidence for carbon and nitrogen fixation [4, 5]. Of particular interest is the role of individuals in carbon and nitrogen cycling as environmental conditions suitable for chemosynthetic and photosynthetic growth vary. This study explores the diversity of cbbM/cbbL [Calvin cycle], aclB/oor/porA [rTCA cycle], nifH [nitrogen fixation], nirK [nitrite reduction] and amoA [ammonia oxidation] genes across a variety of Yellowstone environments. The transition of genetic diversity within sediments and biofilms is focused on the chemosynthetic

  9. Deoxycholic Acid and Selenium Metabolite Methylselenol Exert Common and Distinct Effects on Cell Cycle, Apoptosis, and MAP Kinase Pathway in HCT116 Human Colon Cancer Cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acid deoxycholic acid (DCA) is a known tumor promoter in colon tumor development. The cell growth inhibition induced by DCA may cause compensatory hyperproliferation of colonic epithelial cells and provide selection for subpopulations of cells resistant to DCA’s inhibitory effect. These survivi...

  10. Deoxycholic acid and selenium metabolite methylselenol exert common and distinct effects on cell cycle, apoptosis, and MAP kinase pathway in HCT116 human colon cancer cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cell growth inhibition induced by bile acid deoxycholic acid (DCA) may cause compensatory hyperproliferation of colonic epithelial cells, and consequently increase colon cancer risk. On the other hand, there is increasing evidence for the efficacy of certain forms of selenium (Se) as anticancer ...

  11. ANALYSIS OF DNA STRAND BREAKS INDUCED IN RODENT LIVER IN VIVO, HEPATOCYTES IN VITRO, AND A HUMAN CELL LINE BY CHLORINATED ACETIC ACIDS AND ALDEHYDES

    EPA Science Inventory

    An alkaline unwinding assay was used to quantitate DNA strand breaks (DNA SB) in the livers of rats and mice, in rodent hepatocytes, and in CCRF-CEM cells following treatment with tri- (TCA), di- (DCA) and mono-(MCA) chloroacetic acid and tri-(CH), di)(DCAA) and mono- (CAA) chlor...

  12. Elevated cytokine responses to Vibrio harveyi infection in the Japanese pufferfish (Takifugu rubripes) treated with Lactobacillus paracasei spp. paracasei (06TCa22) isolated from the Mongolian dairy product.

    PubMed

    Biswas, G; Korenaga, H; Nagamine, R; Kawahara, S; Takeda, S; Kikuchi, Y; Dashnyam, B; Yoshida, T; Kono, T; Sakai, M

    2013-09-01

    With the aim of evaluating the effect of a Mongolian dairy product derived Lactobacillus paracasei spp. paracasei (strain 06TCa22) (Lpp) on the cytokine-mediated immune responses to Vibrio harveyi infection, we examined 16 cytokine expressions in the Japanese pufferfish, Takifugu rubripes. Fish were orally treated with the heat-killed Lpp at 1 mg g(-1) body weight d(-1) for 3 days. At 24 h posttreatment, fish were infected by an intramuscular injection of 0.1 mL V. harveyi bacterial suspension (10(8) cfu mL(-1)). Additionally, superoxide anion production (SAP) and phagocytic activity (PA) of head kidney cells were assessed during 120 h postinfection period. Significant up-regulation of pro-inflammatory (IL-1β, IL-6, IL-17A/F-3, TNF-α and TNF-N), cell-mediated immune inducing (IL-12p35, IL-12p40 and IL-18), antiviral/intra-cellular pathogen killing (I-IFN-1 and IFN-γ), anti-inflammatory (IL-10) and lymphocyte agonistic (IL-2, IL-7, IL-15, IL-21 and TGF-β1) cytokines was observed in the treated fish compared to control ones during the pathogen infection. Furthermore, significantly increased SAP and PA (P < 0.01; 0.05) were recorded in the treated fish compared to untreated fish. These results suggest the beneficial role of Lpp in enhancement of cytokine-mediated immunity in the Japanese pufferfish against V. harveyi infection and application of this product as a potential fish immunostimulant. PMID:23769874

  13. All-Trans-Retinoic Acid Enhances Mitochondrial Function in Models of Human Liver.

    PubMed

    Tripathy, Sasmita; Chapman, John D; Han, Chang Y; Hogarth, Cathryn A; Arnold, Samuel L M; Onken, Jennifer; Kent, Travis; Goodlett, David R; Isoherranen, Nina

    2016-05-01

    All-trans-retinoic acid (atRA) is the active metabolite of vitamin A. The liver is the main storage organ of vitamin A, but activation of the retinoic acid receptors (RARs) in mouse liver and in human liver cell lines has also been shown. AlthoughatRA treatment improves mitochondrial function in skeletal muscle in rodents, its role in modulating mitochondrial function in the liver is controversial, and little data are available regarding the human liver. The aim of this study was to determine whetheratRA regulates hepatic mitochondrial activity.atRA treatment increased the mRNA and protein expression of multiple components of mitochondrialβ-oxidation, tricarboxylic acid (TCA) cycle, and respiratory chain. Additionally,atRA increased mitochondrial biogenesis in human hepatocytes and in HepG2 cells with and without lipid loading based on peroxisome proliferator activated receptor gamma coactivator 1αand 1βand nuclear respiratory factor 1 mRNA and mitochondrial DNA quantification.atRA also increasedβ-oxidation and ATP production in HepG2 cells and in human hepatocytes. Knockdown studies of RARα, RARβ, and PPARδrevealed that the enhancement of mitochondrial biogenesis andβ-oxidation byatRA requires peroxisome proliferator activated receptor delta. In vivo in mice,atRA treatment increased mitochondrial biogenesis markers after an overnight fast. Inhibition ofatRA metabolism by talarozole, a cytochrome P450 (CYP) 26 specific inhibitor, increased the effects ofatRA on mitochondrial biogenesis markers in HepG2 cells and in vivo in mice. These studies show thatatRA regulates mitochondrial function and lipid metabolism and that increasingatRA concentrations in human liver via CYP26 inhibition may increase mitochondrial biogenesis and fatty acidβ-oxidation and provide therapeutic benefit in diseases associated with mitochondrial dysfunction. PMID:26921399

  14. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K.

    PubMed

    Huh, Won Bum; Kim, Jong-Eun; Kang, Young-Gyu; Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression. PMID:26066652

  15. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K

    PubMed Central

    Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C.; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression. PMID:26066652

  16. Application of talcum powder, trichloroacetic acid and silver nitrate in female rats for non-surgical sterilization: evaluation of the apoptotic pathway mRNA and miRNA genes.

    PubMed

    Yumrutas, Onder; Kara, Murat; Atilgan, Remzi; Kavak, Salih Burcin; Bozgeyik, Ibrahim; Sapmaz, Ekrem

    2015-04-01

    There are several methods used for non-surgical sterilization in birth control including quinacrine, trichloroacetic acid (TCA), erythromycin, tetracycline, silver nitrate and talcum powder. Among these, talcum powder, TCA and silver nitrate are the most commonly used. However, the toxic and carcinogenic activities of these chemicals in ovarian tissue have been poorly elucidated. This study demonstrates the expression levels of antioxidant, apoptotic and anti-apoptotic genes after administration of talc powder, TCA and silver nitrate for non-surgical sterilization in female rat models. The expression changes of some microRNAs (miR-15b, miR-21, miR-34a and miR-98) that play key roles in the apoptosis pathway were also included. All expression analyses were evaluated with real-time PCR. The expression levels of all genes appeared to be upregulated in the talcum powder group, but the results were not statistically significant. Increased expression of Gsr and Sod1 genes was statistically significant in the talcum powder group. In TCA and silver nitrate group, expression of all genes was appeared to be elevated but only the Gsr expression was statistically significant in the TCA-administrated group; there were no statistically significant changes in the silver nitrate group. miRNA expression levels were increased in talcum powder and TCA-administrated groups, but these results were not significant. Expression levels of miR-15b, miR-21 and miR-98 in the silver nitrate group were significantly increased. Consequently, these chemicals appear to be non-carcinogenic agents for rat ovarian tissue which do not induce apoptosis. However, talcum powder and TCA can be considered as agents that are toxic to ovarian tissue. PMID:25885949

  17. Plasma Acylcarnitine Profiles Suggest Incomplete Fatty Acid ß-Oxidation and Altered Tricarboxylic Cycle Activity in Type 2 Diabetic African-American Women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inefficient muscle long-chain fatty acid (LCFA) combustion is associated with insulin resistance, but molecular links between mitochondrial fat catabolism and insulin action remain controversial. We hypothesized that plasma acylcarnitine profiling would identify distinct metabolite patterns reflect...

  18. Three-Year Breeding Cycle of Rainbow Trout (Oncorhynchus mykiss) Fed a Plant-Based Diet, Totally Free of Marine Resources: Consequences for Reproduction, Fatty Acid Composition and Progeny Survival

    PubMed Central

    Lazzarotto, Viviana; Corraze, Geneviève; Leprevost, Amandine; Quillet, Edwige; Dupont-Nivet, Mathilde; Médale, Françoise

    2015-01-01

    Terrestrial plant resources are increasingly used as substitutes for fish meal and fish oil in fish feed in order to reduce the reliance of aquaculture on marine fishery resources. Although many studies have been conducted to assess the effects of such nutritional transition, no whole breeding cycles of fish fed diets free from marine resources has been reported to date. We therefore studied the reproductive performance of trout after a complete cycle of breeding while consuming a diet totally devoid of marine ingredients and thus of n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs) that play a major role in the formation of ova. Two groups of female rainbow trout were fed from first feeding either a commercial diet (C, marine and plant ingredients), or a 100% plant-based diet (V, blend of plant proteins and vegetable oils). Livers, viscera, carcasses and ova were sampled at spawning and analyzed for lipids and fatty acids. Although the V-diet was devoid of n-3 LC-PUFAs, significant amounts of EPA and DHA were found in livers and ova, demonstrating efficient bioconversion of linolenic acid and selective orientation towards the ova. Some ova were fertilized to assess the reproductive performance and offspring survival. We observed for the first time that trout fed a 100% plant-based diet over a 3-year breeding cycle were able to produce ova and viable alevins, although the ova were smaller. The survival of offspring from V-fed females was lower (-22%) at first spawning, but not at the second. Our study showed that, in addition to being able to grow on a plant-based diet, rainbow trout reared entirely on such a diet can successfully produce ova in which neo-synthesized n-3 LC-PUFAs are accumulated, leading to viable offspring. However, further adjustment of the feed formula is still needed to optimize reproductive performance. PMID:25658483

  19. Three-year breeding cycle of rainbow trout (Oncorhynchus mykiss) fed a plant-based diet, totally free of marine resources: consequences for reproduction, fatty acid composition and progeny survival.

    PubMed

    Lazzarotto, Viviana; Corraze, Geneviève; Leprevost, Amandine; Quillet, Edwige; Dupont-Nivet, Mathilde; Médale, Françoise

    2015-01-01

    Terrestrial plant resources are increasingly used as substitutes for fish meal and fish oil in fish feed in order to reduce the reliance of aquaculture on marine fishery resources. Although many studies have been conducted to assess the effects of such nutritional transition, no whole breeding cycles of fish fed diets free from marine resources has been reported to date. We therefore studied the reproductive performance of trout after a complete cycle of breeding while consuming a diet totally devoid of marine ingredients and thus of n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs) that play a major role in the formation of ova. Two groups of female rainbow trout were fed from first feeding either a commercial diet (C, marine and plant ingredients), or a 100% plant-based diet (V, blend of plant proteins and vegetable oils). Livers, viscera, carcasses and ova were sampled at spawning and analyzed for lipids and fatty acids. Although the V-diet was devoid of n-3 LC-PUFAs, significant amounts of EPA and DHA were found in livers and ova, demonstrating efficient bioconversion of linolenic acid and selective orientation towards the ova. Some ova were fertilized to assess the reproductive performance and offspring survival. We observed for the first time that trout fed a 100% plant-based diet over a 3-year breeding cycle were able to produce ova and viable alevins, although the ova were smaller. The survival of offspring from V-fed females was lower (-22%) at first spawning, but not at the second. Our study showed that, in addition to being able to grow on a plant-based diet, rainbow trout reared entirely on such a diet can successfully produce ova in which neo-synthesized n-3 LC-PUFAs are accumulated, leading to viable offspring. However, further adjustment of the feed formula is still needed to optimize reproductive performance. PMID:25658483

  20. The effects of fulvic acid on microbial denitrification: promotion of NADH generation, electron transfer, and consumption.

    PubMed

    Li, Mu; Su, Yinglong; Chen, Yinguang; Wan, Rui; Zheng, Xiong; Liu, Kun

    2016-06-01

    The heterotrophic denitrification requires the participation of electrons which are derived from direct electron donor (usually nicotinamide adenine dinucleotide (NADH)), and the electrons are transferred via electron transport system in denitrifiers and then consumed by denitrifying enzymes. Despite the reported electron transfer ability of humic substances (HS), the influences of fulvic acid (FA), an ubiquitous major component of HS, on promoting NADH generation, electron transfer, and consumption in denitrification process have never been reported. The presence of FA, compared with the control, was found not only significantly improved the total nitrogen (TN) removal efficiency (99.9 % versus 74.8 %) but remarkably reduced the nitrite accumulation (0.2 against 43.8 mg/L) and N2O emission (0.003 against 0.240 mg nitrogen/mg TN removed). The mechanisms study showed that FA increased the metabolism of carbon source via glycolysis and tricarboxylic acid (TCA) cycle pathways to produce more available NADH. FA also facilitated the electron transfer activities from NADH to denitrifying enzymes via complex I and complex III in electron transport system, which improved the reduction of nitrate and accelerated the transformations of nitrite and N2O, and lower nitrite and N2O accumulations were therefore observed. In addition, the consumption of electrons in denitrification was enhanced due to FA stimulating the synthesis and the catalytic activity of key denitrifying enzymes, especially nitrite reductase and N2O reductase. It will provide an important new insight into the potential effect of FA on microbial denitrification metabolism process and even nitrogen cycle in nature niches. PMID:26894403

  1. Simultaneous quantification of chlorogenic acid and taurocholic acid in human plasma by LC-MS/MS and its application to a pharmacokinetic study after oral administration of Shuanghua Baihe tablets.

    PubMed

    Gu, Pan; Liu, Rui-Juan; Cheng, Min-Lu; Wu, Yao; Zheng, Lu; Liu, Yu-Jie; Ma, Peng-Cheng; Ding, Li

    2016-04-01

    An LC-MS/MS method was developed and validated for the simultaneous quantification of chlorogenic acid (CGA) and taurocholic acid (TCA) in human plasma using hydrochlorothiazide as the internal standard. The chromatographic separation was achieved on a Hedera ODS-2 column with a gradient elution using 10 mmol·L(-1) of ammonium acetate buffer solution containing 0.5% of formic acid - acetonitrile as mobile phase at a flow rate of 300 μL·min(-1). The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring in negative ESI mode. The method was fully validated over the concentration ranges of 0.1-10 ng·mL(-1) for CGA and 2-150 ng·mL(-1) for TCA. It was successfully applied to a pharmacokinetic study of CGA and TCA in healthy Chinese volunteers after oral administration of Shuanghua Baihe tablets (SBTs). In the single-dose study, the maximum plasma concentration (Cmax), time to reach Cmax (Tmax) and elimination half-life (t1/2) of CGA were (0.763 8 ± 0.542 0) ng·mL(-1), (1.0 ± 0.5) h, and (1.3 ± 0.6) h, respectively. In the multiple-dose study, the Cmax, Tmax and t1/2 of CGA were (0.663 7 ± 0.583 3) ng·mL(-1), (1.1 ± 0.5) h, and (1.4 ± 0.7) h, respectively. For TCA, no significant characteristic increasing plasma TCA concentration-time curve was found in the volunteers after oral administration of SBTs, indicating its complicated process in vivo as an endogenous ingredient. PMID:27114321

  2. Nitric oxide (NO), citrulline-NO cycle enzymes, glutamine synthetase, and oxidative status in kainic acid-mediated excitotoxicity in rat brain.

    PubMed

    Swamy, Mummedy; Sirajudeen, Kuttulebbai N S; Chandran, Govindasamy

    2009-01-01

    Neuronal excitation, involving the excitatory glutamate receptors, is recognized as an important underlying mechanism in neurodegenerative disorders. To understand their role in excitotoxicity, the nitric oxide synthase (NOS), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), glutamine synthetase (GS), and arginase activities, along with the concentration of nitrate/nitrite, thiobarbituric acid-reactive substances (TBARS), and total antioxidant status (TAS), were estimated in the cerebral cortex, cerebellum, and brain stem of rats subjected to kainic acid-mediated excitotoxicity. The results of this study clearly demonstrated the increased production of NO by increased activity of NOS. The increased activities of AS and AL suggest the increased and effective recycling of citrulline to arginine in excitotoxicity, making NO production more effective and contributing to its toxic effects. The decreased activity of GS may favor the prolonged availability of glutamic acid, causing excitotoxicity, leading to neuronal damage. The increased formation of TBARS and decreased TAS indicate the presence of oxidative stress in excitotoxicity. PMID:19793024

  3. Effects of quercetin on the sleep-wake cycle in rats: involvement of gamma-aminobutyric acid receptor type A in regulation of rapid eye movement sleep.

    PubMed

    Kambe, Daiji; Kotani, Makiko; Yoshimoto, Makoto; Kaku, Shinsuke; Chaki, Shigeyuki; Honda, Kazuki

    2010-05-12

    The bioflavonoid quercetin is widely found in plants and exerts a large number of biological activities such as anti-hypertensive and anti-inflammatory properties. However, the effect of quercetin on the sleep-wake cycle has not been investigated. In the present study, we investigated the effect of quercetin on sleep-wake regulation. Intraperitoneal administration of quercetin (200mg/kg) significantly increased non-rapid eye movement (non-REM) sleep during dark period in rats, while it significantly decreased REM sleep. The decrease in REM sleep induced by quercetin was blocked by intracerebroventricular (i.c.v.) injection of bicuculline, a GABA(A) receptor antagonist. In contrast, the increase in non-REM sleep induced by quercetin was not affected by i.c.v. injection of bicuculline. Therefore, the present results suggest that quercetin alters the sleep-wake cycle partly through activation of GABA(A) receptors. PMID:20303338

  4. Metabolic effects of elevated temperature on organic acid degradation in ripening Vitis vinifera fruit

    PubMed Central

    Sweetman, C.; Sadras, V. O.; Hancock, R. D.; Soole, K. L.; Ford, C. M.

    2014-01-01

    Berries of the cultivated grapevine Vitis vinifera are notably responsive to temperature, which can influence fruit quality and hence the future compatibility of varieties with their current growing regions. Organic acids represent a key component of fruit organoleptic quality and their content is significantly influenced by temperature. The objectives of this study were to (i) manipulate thermal regimes to realistically capture warming-driven reduction of malate content in Shiraz berries, and (ii) investigate the mechanisms behind temperature-sensitive malate loss and the potential downstream effects on berry metabolism. In the field we compared untreated controls at ambient temperature with longer and milder warming (2–4 °C differential for three weeks; Experiment 1) or shorter and more severe warming (4–6 °C differential for 11 days; Experiment 2). We complemented field trials with control (25/15 °C) and elevated (35/20 °C) day/night temperature controlled-environment trials using potted vines (Experiment 3). Elevating maximum temperatures (4–10 °C above controls) during pre-véraison stages led to higher malate content, particularly with warmer nights. Heating at véraison and ripening stages reduced malate content, consistent with effects typically seen in warm vintages. However, when minimum temperatures were also raised by 4–6 °C, malate content was not reduced, suggesting that the regulation of malate metabolism differs during the day and night. Increased NAD-dependent malic enzyme activity and decreased phosphoenolpyruvate carboxylase and pyruvate kinase activities, as well as the accumulation of various amino acids and γ-aminobutyric acid, suggest enhanced anaplerotic capacity of the TCA cycle and a need for coping with decreased cytosolic pH in heated fruit. PMID:25180109

  5. Cycle Analysis

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop andmore » provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.« less

  6. A Diel Flux Balance Model Captures Interactions between Light and Dark Metabolism during Day-Night Cycles in C3 and Crassulacean Acid Metabolism Leaves1[C][W][OPEN

    PubMed Central

    Cheung, C.Y. Maurice; Poolman, Mark G.; Fell, David. A.; Ratcliffe, R. George; Sweetlove, Lee J.

    2014-01-01

    Although leaves have to accommodate markedly different metabolic flux patterns in the light and the dark, models of leaf metabolism based on flux-balance analysis (FBA) have so far been confined to consideration of the network under continuous light. An FBA framework is presented that solves the two phases of the diel cycle as a single optimization problem and, thus, provides a more representative model of leaf metabolism. The requirement to support continued export of sugar and amino acids from the leaf during the night and to meet overnight cellular maintenance costs forces the model to set aside stores of both carbon and nitrogen during the day. With only minimal constraints, the model successfully captures many of the known features of C3 leaf metabolism, including the recently discovered role of citrate synthesis and accumulation in the night as a precursor for the provision of carbon skeletons for amino acid synthesis during the day. The diel FBA model can be applied to other temporal separations, such as that which occurs in Crassulacean acid metabolism (CAM) photosynthesis, allowing a system-level analysis of the energetics of CAM. The diel model predicts that there is no overall energetic advantage to CAM, despite the potential for suppression of photorespiration through CO2 concentration. Moreover, any savings in enzyme machinery costs through suppression of photorespiration are likely to be offset by the higher flux demand of the CAM cycle. It is concluded that energetic or nitrogen use considerations are unlikely to be evolutionary drivers for CAM photosynthesis. PMID:24596328

  7. Phosphorylation of N-methyl-D-aspartic acid receptor-associated neuronal nitric oxide synthase depends on estrogens and modulates hypothalamic nitric oxide production during the ovarian cycle

    PubMed Central

    Parkash, Jyoti; D'Anglemont De Tassigny, Xavier; Bellefontaine, Nicole; Campagne, Celine; Mazure, Danièle; Buée-Scherrer, Valérie; Prevot, Vincent

    2010-01-01

    Within the preoptic region, nitric oxide (NO) production varies during the ovarian cycle and has the ability to impact hypothalamic reproductive function. One mechanism for the regulation of NO release mediated by estrogens during the estrous cycle includes physical association of the calcium-activated neuronal NO synthase (nNOS) enzyme with the glutamate N-methyl-D-aspartate (NMDA) receptor channels via the postsynaptic density 95 (PSD 95) scaffolding protein. Here, we demonstrate that endogenous variations in estrogens levels during the estrous cycle also coincide with corresponding changes in the state of nNOS Ser1412 phosphorylation, the level of association of this isoform with the NMDA receptor/PSD-95 complex at the plasma membrane and the activity of NOS. Neuronal NOS Ser1412 phosphorylation is maximal on the afternoon of proestrus, when both the levels of estrogens and the physical association of nNOS with NMDA receptors are highest. Estradiol mimicked these effects in ovariectomized (OVX) rats. In addition, the catalytic activity of NOS in membrane protein extracts from the preoptic region, i.e., independent of any functional protein-protein interactions or cell-cell signaling, was significantly increased in estradioltreated OVX rats compared to OVX rats. Finally, λ phosphatase-mediated nNOS dephosphorylation dramatically impaired NOS activity in preoptic region protein extracts, thus demonstrating the important role of phosphorylation in the regulation of NO production in the preoptic region. Taken together, these results yield new insights into the regulation of neuron-derived NO production by gonadal steroids within the preoptic region and raise the possibility that changes in nNOS phosphorylation during fluctuating physiological conditions may be involved in the hypothalamic control of key neuroendocrine functions, such as reproduction. PMID:20371700

  8. Glycolysis and the Tricarboxylic Acid Cycle Are Linked by Alanine Aminotransferase during Hypoxia Induced by Waterlogging of Lotus japonicus1[W][OA

    PubMed Central

    Rocha, Marcio; Licausi, Francesco; Araújo, Wagner L.; Nunes-Nesi, Adriano; Sodek, Ladaslav; Fernie, Alisdair R.; van Dongen, Joost T.

    2010-01-01

    The role of nitrogen metabolism in the survival of prolonged periods of waterlogging was investigated in highly flood-tolerant, nodulated Lotus japonicus plants. Alanine production revealed to be a critical hypoxic pathway. Alanine is the only amino acid whose biosynthesis is not inhibited by nitrogen deficiency resulting from RNA interference silencing of nodular leghemoglobin. The metabolic changes that were induced following waterlogging can be best explained by the activation of alanine metabolism in combination with the modular operation of a split tricarboxylic acid pathway. The sum result of this metabolic scenario is the accumulation of alanine and succinate and the production of extra ATP under hypoxia. The importance of alanine metabolism is discussed with respect to its ability to regulate the level of pyruvate, and this and all other changes are discussed in the context of current models concerning the regulation of plant metabolism. PMID:20089769

  9. In vitro inhibition of OATP-mediated uptake of phalloidin using bile acid derivatives

    SciTech Connect

    Herraez, Elisa; Macias, Rocio I.R.; Vazquez-Tato, Jose; Vicens, Marta; Monte, Maria J.; Marin, Jose J.G.

    2009-08-15

    Hepatocyte uptake of phalloidin is carried out mainly by OATP1B1. We have used this compound as a prototypic substrate and assayed the ability to inhibit OATP-mediated phalloidin transport of four bile acid derivatives (BALU-1, BALU-2, BALU-3 and BALU-4) that showed positive results in preliminary screening. Using Xenopus laevis oocytes for heterologous expression of transporters, BALUs were found to inhibit taurocholic acid (TCA) transport by OATP1B1 (but not OATP1B3) as well as by rat Oatp1a1, Oatp1a4 and Oatp1b2. The study of their ability to inhibit sodium-dependent bile acid transporters revealed that the four BALUs induced an inhibition of rat Asbt-mediated TCA transport, which was similar to TCA-induced self-inhibition. Regarding human NTCP and rat Ntcp, BALU-1 differs from the other three BALUS in its lack of effect on TCA transport by these proteins. Using HPLC-MS/MS and CHO cells stably expressing OATP1B1 the ability of BALU-1 to inhibit the uptake of phalloidin itself by this transporter was confirmed. Kinetic analysis using X. laevis oocytes revealed that BALU-1-induced inhibition of OATP1B1 was mainly due to a competitive mechanism (Ki = 8 {mu}M). In conclusion, BALU-1 may be useful as a pharmacological tool to inhibit the uptake of compounds mainly taken up by OATP1B1 presumably without impairing bile acid uptake by the major carrier accounting for this process, i.e., NTCP.

  10. Glycerol-3-phosphate Acyltransferase Isoform-4 (GPAT4) Limits Oxidation of Exogenous Fatty Acids in Brown Adipocytes.

    PubMed

    Cooper, Daniel E; Grevengoed, Trisha J; Klett, Eric L; Coleman, Rosalind A

    2015-06-12

    Glycerol-3-phosphate acyltransferase-4 (GPAT4) null pups grew poorly during the suckling period and, as adults, were protected from high fat diet-induced obesity. To determine why Gpat4(-/-) mice failed to gain weight during these two periods of high fat feeding, we examined energy metabolism. Compared with controls, the metabolic rate of Gpat4(-/-) mice fed a 45% fat diet was 12% higher. Core body temperature was 1 ºC higher after high fat feeding. Food intake, fat absorption, and activity were similar in both genotypes. Impaired weight gain in Gpat4(-/-) mice did not result from increased heat loss, because both cold tolerance and response to a β3-adrenergic agonist were similar in both genotypes. Because GPAT4 comprises 65% of the total GPAT activity in brown adipose tissue (BAT), we characterized BAT function. A 45% fat diet increased the Gpat4(-/-) BAT expression of peroxisome proliferator-activated receptor α (PPAR) target genes, Cpt1α, Pgc1α, and Ucp1, and BAT mitochondria oxidized oleate and pyruvate at higher rates than controls, suggesting that fatty acid signaling and flux through the TCA cycle were enhanced. To assess the role of GPAT4 directly, neonatal BAT preadipocytes were differentiated to adipocytes. Compared with controls, Gpat4(-/-) brown adipocytes incorporated 33% less fatty acid into triacylglycerol and 46% more into the pathway of β-oxidation. The increased oxidation rate was due solely to an increase in the oxidation of exogenous fatty acids. These data suggest that in the absence of cold exposure, GPAT4 limits excessive fatty acid oxidation and the detrimental induction of a hypermetabolic state. PMID:25918168

  11. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  12. Studies in mice, hamsters, and rats demonstrate that repression of hepatic apoA-I expression by taurocholic acid in mice is not mediated by the farnesoid-X-receptor

    PubMed Central

    Gardès, Christophe; Blum, Denise; Bleicher, Konrad; Chaput, Evelyne; Ebeling, Martin; Hartman, Peter; Handschin, Corinne; Richter, Hans; Benson, G. Martin

    2011-01-01

    It is claimed that apoA-I expression is repressed in mice by cholic acid (CA) and its taurine conjugate, taurocholic acid (TCA) via farnesoid X receptor (FXR) activation. We measured apoA-I expression in mice, hamsters, and rats treated with highly potent and selective synthetic FXR agonists or with TCA. All of the synthetic agonists bound to FXR with high affinity in a scintillation proximity assay. However, TCA did not compete with the radioligand up to the highest concentration used (100 μM). The C-site regulatory region of apoA-I, through which FXR has been reported to regulate its expression, is completely conserved across the species investigated. In both male and female human apoA-I-transgenic mice, we reproduced the previously reported strong inhibition of human apoA-I expression upon treatment with the typical supraphysiological dose of TCA used in such studies. However, in contrast to some previous reports, TCA did not repress murine apoA-I expression in the same mice. Also, more-potent and -selective FXR agonists did not affect human or murine apoA-I expression in this model. In LDL receptor-deficient mice and Golden Syrian hamsters, selective FXR agonists did not affect apoA-I expression, whereas in Wistar rats, some even increased apoA-I expression. In conclusion, selective FXR agonists do not repress apoA-I expression in rodents. Repression of human apoA-I expression by TCA in transgenic mice is probably mediated through FXR-independent mechanisms. PMID:21464203

  13. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves

    NASA Astrophysics Data System (ADS)

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-11-01

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress.

  14. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves

    PubMed Central

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-01-01

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress. PMID:26552588

  15. Covariation Analysis of Serumal and Urinary Metabolites Suggests Aberrant Glycine and Fatty Acid Metabolism in Chronic Hepatitis B

    PubMed Central

    Yang, Xue; Kong, Xiangliang; Cao, Zhiwei; Zhang, Yongyu; Hu, Yiyang; Tang, Kailin

    2016-01-01

    Background Chronic hepatitis b (CHB) is one of the most serious viral diseases threatening human health by putting patients at lifelong risk of cirrhosis and hepatocellular carcinoma (HCC). Although some proofs of altered metabolites in CHB were accumulated, its metabolic mechanism remains poorly understood. Analyzing covariations between metabolites may provide new hints toward underlying metabolic pathogenesis in CHB patients. Methods The present study collected paired urine and serum samples from the same subjects including 145 CHB and 23 healthy controls. A large-scale analysis of metabolites’ covariation within and across biofluids was systematically done to explore the underlying biological evidences for reprogrammed metabolism in CHB. Randomization and relative ranking difference were introduced to reduce bias caused by different sample size. More importantly, functional indication was interpreted by mapping differentially changed covariations to known metabolic pathways. Results Our results suggested reprogrammed pathways related to glycine metabolism, fatty acids metabolism and TCA cycle in CHB patients. With further improvement, the covariation analysis combined with network association study would pave new alternative way to interpret functional clues in clinical multi-omics data. PMID:27228119

  16. Nutrient cycling.

    PubMed

    Bormann, F H; Likens, G E

    1967-01-27

    The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. PMID:17737551

  17. An Optimized Trichloroacetic Acid/Acetone Precipitation Method for Two-Dimensional Gel Electrophoresis Analysis of Qinchuan Cattle Longissimus Dorsi Muscle Containing High Proportion of Marbling

    PubMed Central

    Hao, Ruijie; Adoligbe, Camus; Jiang, Bijie; Zhao, Xianlin; Gui, Linsheng; Qu, Kaixing; Wu, Sen; Zan, Linsen

    2015-01-01

    Longissimus dorsi muscle (LD) proteomics provides a novel opportunity to reveal the molecular mechanism behind intramuscular fat deposition. Unfortunately, the vast amounts of lipids and nucleic acids in this tissue hampered LD proteomics analysis. Trichloroacetic acid (TCA)/acetone precipitation is a widely used method to remove contaminants from protein samples. However, the high speed centrifugation employed in this method produces hard precipitates, which restrict contaminant elimination and protein re-dissolution. To address the problem, the centrifugation precipitates were first grinded with a glass tissue grinder and then washed with 90% acetone (TCA/acetone-G-W) in the present study. According to our result, the treatment for solid precipitate facilitated non-protein contaminant removal and protein re-dissolution, ultimately improving two-dimensional gel electrophoresis (2-DE) analysis. Additionally, we also evaluated the effect of sample drying on 2-DE profile as well as protein yield. It was found that 30 min air-drying did not result in significant protein loss, but reduced horizontal streaking and smearing on 2-DE gel compared to 10 min. In summary, we developed an optimized TCA/acetone precipitation method for protein extraction of LD, in which the modifications improved the effectiveness of TCA/acetone method. PMID:25893432

  18. Sources, sinks, and mechanisms of hydroxyl radical (•OH) photoproduction and consumption in authentic acidic continental cloud waters from Whiteface Mountain, New York: The role of the Fe(r) (r = II, III) photochemical cycle

    NASA Astrophysics Data System (ADS)

    Arakaki, Takemitsu; Faust, Bruce C.

    1998-02-01

    Hydroxyl radical (•OH) photoproduction in 25 authentic acidic (pH = 2.9-4.4) continental cloud waters from Whiteface Mountain, New York was quantified by phenol formed from the •OH-mediated oxidation of benzene (1.2 mM) that was added as an •OH scavenger. Based on the effect of added bisulfite (HSO3-/HOSO2-), an HOOH sink, the •OH photoproduction in these samples was apportioned into two categories: HOOH-dependent sources (dominant), and HOOH-independent sources (minor). On average only a small percentage (median = 9.4%, mean±sta