Sample records for anaerobic energy metabolism

  1. Anaerobic Metabolism 1 ANAEROBIC METABOLISM

    E-print Network

    Prestwich, Ken

    to aerobic metabolsm. This said, it is not uncommon to hear microbiologists talk about anaerobic respiration it for respiration. However, in many animals anaerobic metabolism may occur even when there are large amounts of O2Anaerobic Metabolism 1 ANAEROBIC METABOLISM 1 Introduction About the Next Three Sets of Class Notes

  2. Anaerobic Amino Acid Metabolism

    Microsoft Academic Search

    R. Reggiani; A. Bertani

    2003-01-01

    Anoxic stress induces a strong change in sugar, protein, and amino acid metabolism in higher plants. Sugars are rapidly consumed through the anaerobic glycolysis to sustain energy production. Protein degradation under anoxia is a mechanism to release free amino acids contributing in this way to maintaining the osmotic potential of the tissue under stress. Among free amino acids, a particular

  3. Aerobic and Anaerobic Metabolism Aerobic = oxidative metabolism

    E-print Network

    Jodice, Patrick

    and lizards · Anaerobic metabolism may supply 50-90% of energy during activity · As with many other processes flight is positively related to drag and velocity #12;Laysan Albatross Horned Puffin AspectRatio Red

  4. Inorganic types of fermentation and anaerobic respirations in the evolution of energy-yielding metabolism

    Microsoft Academic Search

    Fujio Egami

    1974-01-01

    We proposed long ago the following sequence as one of the main pathways in the evolution of energy-yielding metabolism: fermentation?nitrate fermentation?nitrate respiration?oxygen respiration. In the present report our concept is presented in a more general form: (1) fermentation? ?(2) fermentation with H2 release?(3) inorganic types of fermentation?(4) anaerobic respirations ?(5) oxygen respiration, based upon recent biological and physical information. The

  5. Anaerobic metabolism of indoleacetate.

    PubMed

    Ebenau-Jehle, Christa; Thomas, Markus; Scharf, Gernot; Kockelkorn, Daniel; Knapp, Bettina; Schühle, Karola; Heider, Johann; Fuchs, Georg

    2012-06-01

    The anaerobic metabolism of indoleacetate (indole-3-acetic acid [IAA]) in the denitrifying betaproteobacterium Azoarcus evansii was studied. The strain oxidized IAA completely and grew with a generation time of 10 h. Enzyme activities that transformed IAA were present in the soluble cell fraction of IAA-grown cells but were 10-fold downregulated in cells grown on 2-aminobenzoate or benzoate. The transformation of IAA did not require molecular oxygen but required electron acceptors like NAD(+) or artificial dyes. The first products identified were the enol and keto forms of 2-oxo-IAA. Later, polar products were observed, which could not yet be identified. The first steps likely consist of the anaerobic hydroxylation of the N-heterocyclic pyrrole ring to the enol form of 2-oxo-IAA, which is catalyzed by a molybdenum cofactor-containing dehydrogenase. This step is probably followed by the hydrolytic ring opening of the keto form, which is catalyzed by a hydantoinase-like enzyme. A comparison of the proteome of IAA- and benzoate-grown cells identified IAA-induced proteins. Owing to the high similarity of A. evansii with strain EbN1, whose genome is known, we identified a cluster of 14 genes that code for IAA-induced proteins involved in the early steps of IAA metabolism. These genes include a molybdenum cofactor-dependent dehydrogenase of the xanthine oxidase/aldehyde dehydrogenase family, a hydantoinase, a coenzyme A (CoA) ligase, a CoA transferase, a coenzyme B(12)-dependent mutase, an acyl-CoA dehydrogenase, a fusion protein of an enoyl-CoA hydratase and a 3-hydroxyacyl-CoA dehydrogenase, a beta-ketothiolase, and a periplasmic substrate binding protein for ABC transport as well as a transcriptional regulator of the GntR family. Five predicted enzymes form or act on CoA thioesters, indicating that soon after the initial oxidation of IAA and possibly ring opening, CoA thioesters are formed, and the carbon skeleton is rearranged, followed by a CoA-dependent thiolytic release of another CoA thioester. We propose a scheme of an anaerobic IAA metabolic pathway that ultimately leads to 2-aminobenzoyl-CoA or benzoyl-CoA. PMID:22447903

  6. Anaerobic Metabolism of Indoleacetate

    PubMed Central

    Ebenau-Jehle, Christa; Thomas, Markus; Scharf, Gernot; Kockelkorn, Daniel; Knapp, Bettina; Schühle, Karola; Heider, Johann

    2012-01-01

    The anaerobic metabolism of indoleacetate (indole-3-acetic acid [IAA]) in the denitrifying betaproteobacterium Azoarcus evansii was studied. The strain oxidized IAA completely and grew with a generation time of 10 h. Enzyme activities that transformed IAA were present in the soluble cell fraction of IAA-grown cells but were 10-fold downregulated in cells grown on 2-aminobenzoate or benzoate. The transformation of IAA did not require molecular oxygen but required electron acceptors like NAD+ or artificial dyes. The first products identified were the enol and keto forms of 2-oxo-IAA. Later, polar products were observed, which could not yet be identified. The first steps likely consist of the anaerobic hydroxylation of the N-heterocyclic pyrrole ring to the enol form of 2-oxo-IAA, which is catalyzed by a molybdenum cofactor-containing dehydrogenase. This step is probably followed by the hydrolytic ring opening of the keto form, which is catalyzed by a hydantoinase-like enzyme. A comparison of the proteome of IAA- and benzoate-grown cells identified IAA-induced proteins. Owing to the high similarity of A. evansii with strain EbN1, whose genome is known, we identified a cluster of 14 genes that code for IAA-induced proteins involved in the early steps of IAA metabolism. These genes include a molybdenum cofactor-dependent dehydrogenase of the xanthine oxidase/aldehyde dehydrogenase family, a hydantoinase, a coenzyme A (CoA) ligase, a CoA transferase, a coenzyme B12-dependent mutase, an acyl-CoA dehydrogenase, a fusion protein of an enoyl-CoA hydratase and a 3-hydroxyacyl-CoA dehydrogenase, a beta-ketothiolase, and a periplasmic substrate binding protein for ABC transport as well as a transcriptional regulator of the GntR family. Five predicted enzymes form or act on CoA thioesters, indicating that soon after the initial oxidation of IAA and possibly ring opening, CoA thioesters are formed, and the carbon skeleton is rearranged, followed by a CoA-dependent thiolytic release of another CoA thioester. We propose a scheme of an anaerobic IAA metabolic pathway that ultimately leads to 2-aminobenzoyl-CoA or benzoyl-CoA. PMID:22447903

  7. Anaerobic energy metabolism in the oligochaete Lumbriculus variegatus Müller

    Microsoft Academic Search

    V. M. Putzer; A. Zwaan; W. Wieser

    1990-01-01

    Anoxia tolerance, glycogen degradation, free amino acid pool, adenylate energy charge and the accumulation and excretion of end products were monitored inLumbriculus variegatus Müller throughout 48 h of anoxia. A transition period lasting about 4 h could be distinguished from subsequent events during which malate, present in high amounts in the resting animals, is utilized, probably by conversion to succinate.

  8. Recovery after anaerobic metabolism in the leech ( Hirudo medicinalis L.)

    Microsoft Academic Search

    H. Schmidt; I. Zerbst-Boroffka

    1993-01-01

    Medicinal leeches (Hirudo medicinalis L.) responded to self-induced hypoxia (72 h) with typical anaerobic metabolism characterized by a decrease in adenylate energy charge, utilization of the substrates glycogen and malate, and accumulation of the main anaerobic endproducts succinate and propionate. Propionate was also excreted into the medium. Ammonia excretion was suppressed. Aerobic recovery resulted in a profound O2 debt. Resynthesis

  9. Anaerobic metabolism of aromatic compounds.

    PubMed

    Fuchs, Georg

    2008-03-01

    Aromatic compounds comprise a wide variety of natural and synthetic compounds that can serve as substrates for bacterial growth. So far, four types of aromatic metabolism are known. (1) The aerobic aromatic metabolism is characterized by the extensive use of molecular oxygen as cosubstrate for oxygenases that introduce hydroxyl groups and cleave the aromatic ring. (2) In the presence of oxygen, facultative aerobes use another so-called hybrid type of aerobic metabolism of benzoate, phenylacetate, and anthranilate (2-aminobenzoate). These pathways use coenzyme A thioesters of the substrates and do not require oxygen for ring cleavage; rather they use an oxygenase/reductase to dearomatize the ring. (3) In the absence of oxygen, facultative aerobes and phototrophs use a reductive aromatic metabolism. Reduction of the aromatic ring of benzoyl-coenzyme A is catalyzed by benzoyl-coenzyme A reductase. This Birch-like reduction is driven by the hydrolysis of 2 ATP molecules. (4) A completely different, still little characterized benzoyl-coenzyme A reductase operates in strict anaerobes, which cannot afford the costly ATP-dependent ring reduction. PMID:18378589

  10. Metabolic energy-based modelling explains product yielding in anaerobic mixed culture fermentations.

    PubMed

    González-Cabaleiro, Rebeca; Lema, Juan M; Rodríguez, Jorge

    2015-01-01

    The fermentation of glucose using microbial mixed cultures is of great interest given its potential to convert wastes into valuable products at low cost, however, the difficulties associated with the control of the process still pose important challenges for its industrial implementation. A deeper understanding of the fermentation process involving metabolic and biochemical principles is very necessary to overcome these difficulties. In this work a novel metabolic energy based model is presented that accurately predicts for the first time the experimentally observed changes in product spectrum with pH. The model predicts the observed shift towards formate production at high pH, accompanied with ethanol and acetate production. Acetate (accompanied with a more reduced product) and butyrate are predicted main products at low pH. The production of propionate between pH 6 and 8 is also predicted. These results are mechanistically explained for the first time considering the impact that variable proton motive potential and active transport energy costs have in terms of energy harvest over different products yielding. The model results, in line with numerous reported experiments, validate the mechanistic and bioenergetics hypotheses that fermentative mixed cultures products yielding appears to be controlled by the principle of maximum energy harvest and the necessity of balancing the redox equivalents in absence of external electron acceptors. PMID:25992959

  11. Re-interpreting anaerobic metabolism: an argument for the application of both anaerobic glycolysis and excess post-exercise oxygen consumption (EPOC) as independent sources of energy expenditure

    Microsoft Academic Search

    Christopher B. Scott

    1998-01-01

    Due to current technical difficulties and changing cellular conditions, the measurement of anaerobic and recovery energy\\u000a expenditure remains elusive. During rest and low-intensity steady-state exercise, indirect calorimetric measurements successfully\\u000a represent energy expenditure. The same steady-state O2 uptake methods are often used to describe the O2 deficit and excess post-oxygen consumption (EPOC): 1 l O2 = 5?kcal = 20.9?kJ. However, an

  12. Anaerobic Metabolism of Aromatic Compounds

    Microsoft Academic Search

    GEORG FUCHS

    2008-01-01

    Aromatic compounds comprise a wide variety of natural and synthetic compounds that can serve as substrates for bacterial growth. So far, four types of aromatic metabolism are known. (1) The aerobic aromatic metabolism is characterized by the extensive use of molecular oxygen as co- substrate for oxygenases that introduce hydroxyl groups and cleave the aromatic ring. (2) In the presence

  13. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  14. Anaerobic metabolism in Brassica seedlings

    NASA Astrophysics Data System (ADS)

    Park, Myoung-Ryoul; Hasenstein, Karl H.

    Germination typically depends on oxidative respiration. The lack of convection under space conditions may create hypoxic or conditions during seed germination. We investigated the effect of reduced oxygen on seed germination and metabolism to understand how metabolic constraints affect seed growth and responsiveness to reorientation. Germination was completely inhibited when seeds were imbibed in the absence of oxygen; germination occurred at 5% oxygen and higher levels. Adding oxygen after 72 h resulted in immediate germination (protrusion of the radicle). Hypoxia typically activates alcohol dehydrogenase (ADH, EC 1.1.1.1) and lactate dehydrogenase (LDH, EC 1.1.1.27) which produce ethanol and/or L-lactate, respectively. We report on the expression of ADH1 and LDH1, and changes in total soluble sugars, starch, pH, and L-lactate in seedlings grown at 28°C in 0, 2.5, 5, 10% and ambient (21%) oxygen conditions as controls. The highest consumption (lowest level) of sugars was seen at 0% oxygen but the lowest level of starch occurred 24 h after imbibition under ambient condition. Expression levels of ADH1 in ambient oxygen condition increased within 24 h but increased threefold under hypoxic conditions; LDH1 increased up to 8-fold under hypoxia compared to controls but ADH1 and LDH1 were less expressed as the oxygen levels increased. The intracellular pH of seeds decreased as the content of L-lactate increased for all oxygen concentrations. These results indicate that germination of Brassica is sensitive to oxygen levels and that oxygen availability during germination is an important factor for metabolic activities. (Supported by NASA grant NNX10AP91G)

  15. Metabolic activity of pathogenic bacteria during semicontinuous anaerobic digestion.

    PubMed Central

    Kearney, T E; Larkin, M J; Levett, P N

    1994-01-01

    In natural environments such as anaerobic digesters, bacteria are frequently subjected to the stress of nutrient fluxes because of the continual changes in the flow of nutrients, and to survive, they must be capable of adapting readily to nutrient changes. In this study, the metabolic activities of Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Listeria monocytogenes, and Campylobacter jejuni were studied within culture bags (Versapor-200 filters, 0.22-microns pore size) in laboratory anaerobic digesters. The metabolic activity of these bacteria was indicated by their adenylate energy charge (EC) ratios and their ability to incorporate [3H]thymidine, which was related to the respective changes in viable numbers within the culture bags during anaerobic digestion. Fluctuations in the adenylate EC ratios, the uptake of [3H]thymidine, and the viable numbers of E. coli, S. typhimurium, Y. enterocolitica, and L. monocytogenes cells were probably due to constant changes in the amount of available nutrients within the anaerobic digesters. The viability of S. typhimurium increased quickly after a fresh supply of nutrients was added to the system as indicated by the uptake of [3H]thymidine and an increase in the adenylate EC ratios. The viable numbers of E. coli, S. typhimurium, Y. enterocolitica, and L. monocytogenes organisms declined rapidly from 10(7) to 10(8) CFU/ml to 10(3) to 10(4) CFU/ml and remained at this level for an indefinite period. The decimal reduction time calculated during the period of exponential decline ranged from 0.8 to 1.2 days for these bacteria. C. jejuni had the greatest mean decimal reduction time value (3.6 days).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7986040

  16. A novel mode of lactate metabolism in strictly anaerobic bacteria.

    PubMed

    Weghoff, Marie Charlotte; Bertsch, Johannes; Müller, Volker

    2015-03-01

    Lactate is a common substrate for major groups of strictly anaerobic bacteria, but the biochemistry and bioenergetics of lactate oxidation is obscure. The high redox potential of the pyruvate/lactate pair of E0 '?=?-190?mV excludes direct NAD(+) reduction (E0 '?=?-320?mV). To identify the hitherto unknown electron acceptor, we have purified the lactate dehydrogenase (LDH) from the strictly anaerobic, acetogenic bacterium Acetobacterium woodii. The LDH forms a stable complex with an electron-transferring flavoprotein (Etf) that exhibited NAD(+) reduction only when reduced ferredoxin (Fd(2-) ) was present. Biochemical analyses revealed that the LDH/Etf complex of A.?woodii uses flavin-based electron confurcation to drive endergonic lactate oxidation with NAD(+) as oxidant at the expense of simultaneous exergonic electron flow from reduced ferredoxin (E0 '???-500?mV) to NAD(+) according to: lactate?+?Fd(2-) ?+?2 NAD(+) ???pyruvate?+?Fd?+?2 NADH. The reduced Fd(2-) is regenerated from NADH by a sequence of events that involves conversion of chemical (ATP) to electrochemical ( ? ? ˜ Na + ) and finally redox energy (Fd(2-) from NADH) via reversed electron transport catalysed by the Rnf complex. Inspection of genomes revealed that this metabolic scenario for lactate oxidation may also apply to many other anaerobes. PMID:24762045

  17. Integrated Analysis of Protein Complexes and Regulatory Networks Involved in Anaerobic Energy Metabolism of Shewanella Oneidensis MR-1

    SciTech Connect

    Tiedje, James M.

    2005-06-01

    Anaerobic Nitrate Reduction. Nitrate is an extensive co-contaminant at some DOE sites making metal and radionuclide reduction problematic. Hence, we sought to better understand the nitrate reduction pathway and its control in S. oneidensis MR-1. It is not known whether the nitrate reduction is by denitrification or dissimilatory nitrate reduction into ammonium (DNRA). By both physiological and genetic evidence, we proved that DNRA is the nitrate reduction pathway in this organism. Using the complete genome sequence of S. oneidensis MR-1, we identified a gene encoding a periplasmic nitrate reductase based on its 72% sequence identity with the napA gene in E. coli. Anaerobic growth of MR-1 on nitrate was abolished in a site directed napA mutant, indicating that NapA is the only nitrate reductase present. The anaerobic expression of napA and nrfA, a homolog of the cytochrome b552 nitrite reductase in E. coli, increased with increasing nitrate concentration until a plateau was reached at 3 mM KNO3. This indicates that these genes are not repressed by increasing concentrations of nitrate. The reduction of nitrate can generate intermediates that can be toxic to the microorganism. To determine the genetic response of MR-1 to high concentrations of nitrate, DNA microarrays were used to obtain a complete gene expression profile of MR-1 at low (1 mM) versus high (40 mM) nitrate concentrations. Genes encoding transporters and efflux pumps were up-regulated, perhaps as a mechanism to export toxic compounds. In addition, the gene expression profile of MR-1, grown anaerobically with nitrate as the only electron acceptor, suggested that this dissimilatory pathway contributes to N assimilation. Hence the nitrate reduction pathway could serve a dual purpose. The role of EtrA, a homolog of Fnr (global anaerobic regulator in E. coli) was examined using an etrA deletion mutant we constructed, S. oneidensis EtrA7-1.

  18. Acetate Metabolism in Anaerobes from the Domain Archaea

    PubMed Central

    Ferry, James G.

    2015-01-01

    Acetate and acetyl-CoA play fundamental roles in all of biology, including anaerobic prokaryotes from the domains Bacteria and Archaea, which compose an estimated quarter of all living protoplasm in Earth’s biosphere. Anaerobes from the domain Archaea contribute to the global carbon cycle by metabolizing acetate as a growth substrate or product. They are components of anaerobic microbial food chains converting complex organic matter to methane, and many fix CO2 into cell material via synthesis of acetyl-CoA. They are found in a diversity of ecological habitats ranging from the digestive tracts of insects to deep-sea hydrothermal vents, and synthesize a plethora of novel enzymes with biotechnological potential. Ecological investigations suggest that still more acetate-metabolizing species with novel properties await discovery. PMID:26068860

  19. Acetate Metabolism in Anaerobes from the Domain Archaea.

    PubMed

    Ferry, James G

    2015-01-01

    Acetate and acetyl-CoA play fundamental roles in all of biology, including anaerobic prokaryotes from the domains Bacteria and Archaea, which compose an estimated quarter of all living protoplasm in Earth's biosphere. Anaerobes from the domain Archaea contribute to the global carbon cycle by metabolizing acetate as a growth substrate or product. They are components of anaerobic microbial food chains converting complex organic matter to methane, and many fix CO2 into cell material via synthesis of acetyl-CoA. They are found in a diversity of ecological habitats ranging from the digestive tracts of insects to deep-sea hydrothermal vents, and synthesize a plethora of novel enzymes with biotechnological potential. Ecological investigations suggest that still more acetate-metabolizing species with novel properties await discovery. PMID:26068860

  20. Energy metabolism in nuclear reprogramming

    PubMed Central

    Folmes, Clifford DL; Nelson, Timothy J; Terzic, Andre

    2012-01-01

    Nuclear reprogramming with stemness factors enables resetting of somatic differentiated tissue back to the pluripotent ground state. Recent evidence implicates mitochondrial restructuring and bioenergetic plasticity as key components underlying execution of orchestrated dedifferentiation and derivation of induced pluripotent stem cells. Aerobic to anaerobic transition of somatic oxidative energy metabolism into a glycolytic metabotype promotes proficient reprogramming, establishing a novel regulator of acquired stemness. Metabolomic profiling has further identified specific metabolic remodeling traits defining lineage redifferentiation of pluripotent cells. Therefore, mitochondrial biogenesis and energy metabolism comprise a vital axis for biomarker discovery, intimately reflecting the molecular dynamics fundamental for the resetting and redirection of cell fate. PMID:22103608

  1. Energy metabolism in nuclear reprogramming.

    PubMed

    Folmes, Clifford D L; Nelson, Timothy J; Terzic, Andre

    2011-12-01

    Nuclear reprogramming with stemness factors enables resetting of somatic differentiated tissue back to the pluripotent ground state. Recent evidence implicates mitochondrial restructuring and bioenergetic plasticity as key components underlying execution of orchestrated dedifferentiation and derivation of induced pluripotent stem cells. Aerobic to anaerobic transition of somatic oxidative energy metabolism into a glycolytic metabotype promotes proficient reprogramming, establishing a novel regulator of acquired stemness. Metabolomic profiling has further identified specific metabolic remodeling traits defining lineage redifferentiation of pluripotent cells. Therefore, mitochondrial biogenesis and energy metabolism comprise a vital axis for biomarker discovery, intimately reflecting the molecular dynamics fundamental for the resetting and redirection of cell fate. PMID:22103608

  2. Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid.

    PubMed

    Trueblood, Lloyd A; Seibel, Brad A

    2014-08-01

    Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals. PMID:25079893

  3. Repeated sprint performance and metabolic recovery curves: effects of aerobic and anaerobic characteristics.

    PubMed

    Aguiar, Rafael Alves de; Turnes, Tiago; Cruz, Rogério Santos de Oliveira; Salvador, Amadeo Félix; Caputo, Fabrizio

    2015-05-01

    To examine the influence of aerobic and anaerobic indices on repeated sprint (RS) performance and ability (RSA), 8 sprinters (SPR), 8 endurance runners (END), and 8 active participants (ACT) performed the following tests: (i) incremental test; (ii) 1-min test to determine first decay time constant of pulmonary oxygen uptake off-kinetics and parameters related to anaerobic energy supply, lactate exchange, and removal abilities from blood lactate kinetics; and (iii) RS test (ten 35-m sprints, departing every 20 s) to determine best (RSbest) and mean (RSmean) sprint times and percentage of sprint decrement (%Dec). While SPR had a 98%-100% likelihood of having the fastest RSbest (Cohen's d of 1.8 and 1.4 for ACT and END, respectively) and RSmean (2.1 and 0.9 for ACT and END, respectively), END presented a 97%-100% likelihood of having the lowest %Dec (0.9 and 2.2 for ACT and SPR, respectively). RSmean was very largely correlated with RSbest (r = 0.85) and moderately correlated with estimates of anaerobic energy supply (r = -0.40 to -0.49). RSmean adjusted for RSbest (which indirectly reflects RSA) was largely correlated with lactate exchange ability (r = 0.55). Our results confirm the importance of locomotor- and anaerobic-related variables to RS performance, and highlight the importance of disposal of selected metabolic by-products to RSA. PMID:25853893

  4. Metabolic Interactions Between Methanogenic Consortia and Anaerobic Respiring Bacteria

    Microsoft Academic Search

    A. J. M. Stams; S. J. W. H. Oude Elferink; P. Westermann

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective\\u000a electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic\\u000a respiring bacteria are toxic to methanogenic consortia. Despite the potentially adverse effects, only few inorganic electron\\u000a acceptors potentially utilizable for anaerobic respiration have been investigated with respect

  5. Anaerobic and aerobic metabolism of diverse aromatic compounds by the photosynthetic bacterium Rhodopseudomonas palustris.

    PubMed Central

    Harwood, C S; Gibson, J

    1988-01-01

    The purple nonsulfur photosynthetic bacterium Rhodopseudomonas palustris used diverse aromatic compounds for growth under anaerobic and aerobic conditions. Many phenolic, dihydroxylated, and methoxylated aromatic acids, as well as aromatic aldehydes and hydroaromatic acids, supported growth of strain CGA001 in both the presence and absence of oxygen. Some compounds were metabolized under only aerobic or under only anaerobic conditions. Two other strains, CGC023 and CGD052, had similar anaerobic substrate utilization patterns, but CGD052 was able to use a slightly larger number of compounds for growth. These results show that R. palustris is far more versatile in terms of aromatic degradation than had been previously demonstrated. A mutant (CGA033) blocked in aerobic aromatic metabolism remained wild type with respect to anaerobic degradative abilities, indicating that separate metabolic pathways mediate aerobic and anaerobic breakdown of diverse aromatics. Another mutant (CGA047) was unable to grow anaerobically on either benzoate or 4-hydroxybenzoate, and these compounds accumulated in growth media when cells were grown on more complex aromatic compounds. This indicates that R. palustris has two major anaerobic routes for aromatic ring fission, one that passes through benzoate and one that passes through 4-hydroxybenzoate. Images PMID:3377491

  6. Manipulation of step height and its effect on lactate metabolism during a one-minute anaerobic step test.

    PubMed

    Nguyen, Brian D; Gillum, Trevor L

    2015-06-01

    Nguyen, BD and Gillum, TL. Manipulation of step height and its effect on lactate metabolism during a one-minute anaerobic step test. J Strength Cond Res 29(6): 1578-1583, 2015-The purpose of this study was to observe the effects of the 1-minute anaerobic step test on lactate production. In addition, a comparison of postexercise lactate levels between the traditional 40-cm step height and a modified 20-cm step height was tested along with multiple biomechanical components such as torque, knee angle, and power. A convenience sample of 9 healthy moderately trained individuals were recruited for this experiment. Each subject performed the 1-minute anaerobic step test in a counterbalanced, crossover, and repeated-measures design. They performed 2 trials, 1 with a 40-cm step height and another with a 20-cm step height. Results showed statistical significance in terms of the postexercise lactate concentration (40 cm: 8.04 ± 2.13 mmol·L; 20 cm: 6.18 ± 2.62 mmol·L) and lactate production (40 cm: 5.36 ± 2.73 mmol·L; 20 cm: 3.06 ± 2.96 mmol·L) between the 2 step heights (p ? 0.05). With a lowered step height, the moment arm decreased significantly, which lowered the torque placed on the knee joint. Knee angle and power both decreased with a lowered step height of 20 cm. These results suggest that the 1-minute anaerobic step test is effective at eliciting lactate and can be used as an anaerobic exercise modality to train the anaerobic energy system. Furthermore, a step height of 40 cm seemed to be more effective at taxing the anaerobic energy system and eliciting lactate compared with a step height of 20 cm. PMID:25486300

  7. Minimal metabolic engineering of Saccharomyces cerevisiae for efficient anaerobic xylose fermentation: a proof of principle

    Microsoft Academic Search

    Marko Kuyper; Aaron A Winkler; Johannes P van Dijken; Jack T Pronk

    2004-01-01

    When xylose metabolism in yeasts proceeds exclusively via NADPH-specific xylose reductase and NAD-specific xylitol dehydrogenase, anaerobic conversion of the pentose to ethanol is intrinsically impossible. When xylose reductase has a dual specificity for both NADPH and NADH, anaerobic alcoholic fermentation is feasible but requires the formation of large amounts of polyols (e.g., xylitol) to maintain a closed redox balance. As

  8. Anaerobic Carbon Metabolism by the Tricarboxylic Acid Cycle 1

    PubMed Central

    Vanlerberghe, Greg C.; Horsey, Anne K.; Weger, Harold G.; Turpin, David H.

    1989-01-01

    Nitrogen-limited cells of Selenastrum minutum (Naeg.) Collins are able to assimilate NH4+ in the dark under anaerobic conditions. Addition of NH4+ to anaerobic cells results in a threefold increase in tricarboxylic acid cycle (TCAC) CO2 efflux and an eightfold increase in the rate of anaplerotic carbon fixation via phosphoenolpyruvate carboxylase. Both of these observations are consistent with increased TCAC carbon flow to supply intermediates for amino acid biosynthesis. Addition of H14CO3? to anaerobic cells assimilating NH4+ results in the incorporation of radiolabel into the ?-carboxyl carbon of glutamic acid. Incorporation of radiolabel into glutamic acid is not simply a short-term phenomenon following NH4+ addition as the specific activity of glutamic acid increases over time. This indicates that this alga is able to maintain partial oxidative TCAC carbon flow while under anoxia to supply ?-ketoglutarate for glutamate production. During dark aerobic NH4+ assimilation, no radiolabel appears in fumarate or succinate and only a small amount occurs in malate. During anaerobic NH4+ assimilation, these metabolites contain a large proportion of the total radiolabel and radiolabel accumulates in succinate over time. Also, the ratio of dark carbon fixation to NH4+ assimilation is much higher under anaerobic than aerobic conditions. These observations suggest the operation of a partial reductive TCAC from oxaloacetic acid to malate, fumarate, and succinate. Such a pathway might contribute to redox balance in an anaerobic cell maintaining partial oxidative TCAC activity. PMID:16667215

  9. Anaerobic metabolism of phthalate and other aromatic compounds by a denitrifying bacterium. [Pseudomonas sp

    SciTech Connect

    Nozawa, T.; Maruyama, Y. (Univ. of Tokyo (Japan))

    1988-12-01

    The anaerobic metabolism of phthalate and other aromatic compounds by the denitrifying bacterium Pseudomonas sp. strain P136 was studied. Benzoate, cyclohex-1-ene-carboxylate, 2-hydroxycyclohexanecarboxylate, and pimelate were detected as predominant metabolic intermediates during the metabolism of three isomers of phthalate, m-hydroxybenzoate, p-hydroxybenzoate, and cyclohex-3-ene-carboxylate. Inducible acyl-coeznyme A synthetase activities for phthalates, benzoate, cyclohex-1-ene-carboxylate, and cyclohex-3-ene-carboxylate were detected in the cells grown on aromatic compounds. Simultaneous adaptation to these aromatic compounds also occurred. A similar phenomenon was observed in the aerobic metabolism of aromatic compounds by this strain. A new pathway for the anaerobic metabolism of phthalate and a series of other aromatic compounds by this strain was proposed. Some properties of the regulation of this pathway were also discussed.

  10. Stepwise metabolic adaption from pure metabolization to balanced anaerobic growth on xylose explored for recombinant Saccharomyces cerevisiae

    PubMed Central

    2014-01-01

    Background To effectively convert lignocellulosic feedstocks to bio-ethanol anaerobic growth on xylose constitutes an essential trait that Saccharomyces cerevisiae strains normally do not adopt through the selective integration of a xylose assimilation route as the rate of ATP-formation is below energy requirements for cell maintenance (mATP). To enable cell growth extensive evolutionary and/or elaborate rational engineering is required. However the number of available strains meeting demands for process integration are limited. In this work evolutionary engineering in just two stages coupled to strain selection under strict anaerobic conditions was carried out with BP10001 as progenitor. BP10001 is an efficient (Yethanol?=?0.35 g/g) but slow (qethanol?=?0.05?±?0.01 g/gBM/h) xylose-metabolizing recombinant strain of Saccharomyces cerevisiae that expresses an optimized yeast-type xylose assimilation pathway. Results BP10001 was adapted in 5 generations to anaerobic growth on xylose by prolonged incubation for 91 days in sealed flasks. Resultant strain IBB10A02 displayed a specific growth rate ? of 0.025?±?0.002 h-1 but produced large amounts of glycerol and xylitol. In addition growth was strongly impaired at pH below 6.0 and in the presence of weak acids. Using sequential batch selection and IBB10A02 as basis, IBB10B05 was evolved (56 generations). IBB10B05 was capable of fast (??=?0.056?±?0.003 h-1; qethanol?=?0.28?±?0.04 g/gBM/h), efficient (Yethanol?=?0.35?±?0.02 g/g), robust and balanced fermentation of xylose. Importantly, IBB10A02 and IBB10B05 displayed a stable phenotype. Unlike BP10001 both strains displayed an unprecedented biphasic formation of glycerol and xylitol along the fermentation time. Transition from a glycerol- to a xylitol-dominated growth phase, probably controlled by CO2/HCO3-, was accompanied by a 2.3-fold increase of mATP while YATP (= 87?±?7 mmolATP/gBM) remained unaffected. As long as glycerol constituted the main by-product energetics of anaerobic growth on xylose and glucose were almost identical. Conclusions In just 61 generation IBB10B05, displaying ~530% improved strain fitness, was evolved from BP10001. Its excellent xylose fermentation properties under industrial relevant conditions were proven and rendered it competitive. Based on detailed analysis of growth energetics we showed that mATP was predominantly determined by the type of polyol formed rather than, as previously assumed, substrate-specific. PMID:24606998

  11. Anaerobic carbon metabolism by the tricarboxylic acid cycle

    SciTech Connect

    Vanlerberghe, G.C.; Horsey, A.K.; Weger, H.G.; Turpin, D.H. (Queen's Univ., Kingston, Ontario (Canada))

    1989-12-01

    Nitrogen-limited cells of Selenastrum minutum (Naeg.) Collins are able to assimilate NH{sub 4}{sup +} in the dark under anaerobic conditions. Addition of NH{sub 4}{sup +} to anaerobic cells results in a threefold increase in tricarboxylic acid cycle (TCAC) CO{sub 2} efflux and an eightfold increase in the rate of anaplerotic carbon fixation via phosphoenspyruvate carboxylase. Both of these observations are consistent with increased TCAC carbon flow to supply intermediates for amino acid biosynthesis. Addition of H{sup 14}CO{sub 3}{sup {minus}} to anaerobic cells assimilating NH{sub 4}{sup +} results in the incorporation of radiolabel into the {alpha}-carboxyl carbon of glutamic acid. Incorporation of radiolabel into glutamic acid is not simply a short-term phenomenon following NH{sub 4}{sup +} addition as the specific activity of glutamic acid increases over time. This indicates that this alga is able to maintain partial oxidative TCAC carbon flow while under anoxia to supply {alpha}ketoglutarate for glutamate production. During dark aerobic NH{sub 4}{sup +} assimilation, no radiolabel appears in fumarate or succinate and only a small amount occurs in malate. During anaerobic NH{sub 4}{sup +} assimilation, these metabolites contain a large proportion of the total radiolabel and radiolabel accumulates in succinate over time. Also, the ratio of dark carbon fixation to NH{sub 4}{sup +} assimilation is much higher under anaerobic than aerobic conditions. These observations suggest the operation of a partial reductive TCAC from oxaloacetic acid to malate, fumarate, and succinate. Such a pathway might contribute to redox balance in an anaerobic cell maintaining partial oxidative TCAC activity.

  12. Ontogenetic effects on aerobic and anaerobic metabolism during jumping in the American locust, Schistocerca americana

    Microsoft Academic Search

    Scott D. Kirkton; Jared A. Niska; Jon F. Harrison

    2005-01-01

    Developing vertebrates increase both their locomotory power output and endurance due to ontogenetic improvements in anaerobic and aerobic metabolic capacities. Do similar patterns hold for insect locomotion, or do longer tracheal lengths create problems for oxygen delivery in older animals? We forced developing American locust grasshoppers (Schistocerca americana) to jump repeatedly and examined the effect of development on power output,

  13. Comparative Genomic Analysis of dha Regulon and Related Genes for Anaerobic Glycerol Metabolism in Bacteria

    Microsoft Academic Search

    Jibin Sun; Joop van den Heuvel; Philippe Soucaille; Yinbo Qu; An-Ping Zeng

    2003-01-01

    The dihydroxyacetone (dha) regulon of bacteria encodes genes for the anaerobic metabolism of glycerol. In this work, genomic data are used to analyze and compare the dha regulon and related genes in different organisms in silico with respect to gene organization, sequence similarity, and possible functions. Database searches showed that among the organisms, the genomes of which have been sequenced

  14. Anaerobic Fermentation of Glycerol in Paenibacillus macerans: Metabolic Pathways and Environmental Determinants?

    PubMed Central

    Gupta, Ashutosh; Murarka, Abhishek; Campbell, Paul; Gonzalez, Ramon

    2009-01-01

    Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paenibacillus, able to ferment hexoses, deoxyhexoses, pentoses, cellulose, and hemicellulose. However, little is known about glycerol metabolism in this organism, and some studies have reported that glycerol is not fermented. Despite these reports, we found that several P. macerans strains are capable of anaerobic fermentation of glycerol. One of these strains, P. macerans N234A, grew fermentatively on glycerol at a maximum specific growth rate of 0.40 h?1 and was chosen for further characterization. The use of [U-13C]glycerol and further analysis of extracellular metabolites and proteinogenic amino acids via nuclear magnetic resonance (NMR) spectroscopy allowed identification of ethanol, formate, acetate, succinate, and 1,2-propanediol (1,2-PDO) as fermentation products and demonstrated that glycerol is incorporated into cellular components. A medium formulation with low concentrations of potassium and phosphate, cultivation at acidic pH, and the use of a CO2-enriched atmosphere stimulated glycerol fermentation and are proposed to be environmental determinants of this process. The pathways involved in glycerol utilization and synthesis of fermentation products were identified using NMR spectroscopy in combination with enzyme assays. Based on these studies, the synthesis of ethanol and 1,2-PDO is proposed to be a metabolic determinant of glycerol fermentation in P. macerans N234A. Conversion of glycerol to ethanol fulfills energy requirements by generating one molecule of ATP per molecule of ethanol synthesized. Conversion of glycerol to 1,2-PDO results in the consumption of reducing equivalents, thus facilitating redox balance. Given the availability, low price, and high degree of reduction of glycerol, the high metabolic rates exhibited by P. macerans N234A are of paramount importance for the production of fuels and chemicals. PMID:19617389

  15. The metabolism of benzoate by Moraxella species through anaerobic nitrate respiration. Evidence for a reductive pathway.

    PubMed Central

    Williams, R J; Evans, W C

    1975-01-01

    Moraxella sp. isolated from soil grows anaerobically on benzoate by nitrate respiration; nitrate or nitrite are obligatory electron acceptors, being reduced to molecular N2 during the catabolism of the substrate. This bacterium also grows aerobically on benzoate. 2. Aerobically, benzoate is metabolized by ortho cleavage of catechol followed by the beta-oxoadipate pathway. 3. Cells of Moraxella grown anaerobically on benzoate are devoid of ortho and meta cleavage enzymes; cyclohexanecarboxylate and 2-hydroxycyclohexanecarboxylate were detected in the anaerobic culture fluid. 4. [ring-U-14C]Benzoate, incubated anaerobically with cells in nitrate-phosphate buffer, gave rise to labelled 2-hydroxycyclohexanecarboxylate and adipate. When [carboxy-14C]benzoate was used, 2-hydroxycyclohexanecarboxylate was radioactive but the adipate was not labelled. A decarboxylation reaction intervenes at some stage between these two metabolites. 5. The anaerobic metabolism of benzoate by Moraxella sp. through nitrate respiration takes place by the reductive pathway (Dutton & Evans, 1969). Hydrogenation of the aromatic ring probably occurs via cyclohexa-2,5-dienecarboxylate and cyclohex-1-enecarboxylate to give cyclohexanecarboxylate. The biochemistry of this reductive process remains unclear. 6. CoA thiol esterification of cyclohexanecarboxylate followed by beta-oxidation via the unsaturated and hydroxy esters, would afford 2-oxocyclohexanecarboxylate. Subsequent events in the Moraxella culture differ from those occurring with Rhodopseudomonas palustris; decarboxylation precedes hydrolytic cleavage of the alicyclic ring to produce adipate in the former, whereas in the latter the keto ester undergoes direct hydrolytic fission to pimelate. PMID:1156389

  16. Enhancing syntrophic metabolism in up-flow anaerobic sludge blanket reactors with conductive carbon materials.

    PubMed

    Zhao, Zhiqiang; Zhang, Yaobin; Woodard, T L; Nevin, K P; Lovley, D R

    2015-09-01

    Syntrophic metabolism of alcohols and fatty acids is a critical step in anaerobic digestion, which if enhanced can better stabilize the process and enable shorter retention times. Direct interspecies electron transfer (DIET) has recently been recognized as an alternative route to hydrogen interspecies transfer as a mechanism for interspecies syntrophic electron exchange. Therefore, the possibility of accelerating syntrophic metabolism of ethanol in up-flow anaerobic sludge blanket (UASB) reactors by incorporating conductive materials in reactor design was investigated. Graphite, biochar, and carbon cloth all immediately enhanced methane production and COD removal. As the hydraulic retention time was decreased the increased effectiveness of treatment in reactors with conductive materials increased versus the control reactor. When these conductive materials were removed from the reactors rates of syntrophic metabolism declined to rates comparable to the control reactor. These results suggest that incorporating conductive materials in the design of UASB reactors may enhance digester effectiveness. PMID:25989089

  17. Decarboxylating and nondecarboxylating glutaryl-coenzyme A dehydrogenases in the aromatic metabolism of obligately anaerobic bacteria.

    PubMed

    Wischgoll, Simon; Taubert, Martin; Peters, Franziska; Jehmlich, Nico; von Bergen, Martin; Boll, Matthias

    2009-07-01

    In anaerobic bacteria using aromatic growth substrates, glutaryl-coenzyme A (CoA) dehydrogenases (GDHs) are involved in the catabolism of the central intermediate benzoyl-CoA to three acetyl-CoAs and CO(2). In this work, we studied GDHs from the strictly anaerobic, aromatic compound-degrading organisms Geobacter metallireducens (GDH(Geo)) (Fe[III] reducing) and Desulfococcus multivorans (GDH(Des)) (sulfate reducing). GDH(Geo) was purified from cells grown on benzoate and after the heterologous expression of the benzoate-induced bamM gene. The gene coding for GDH(Des) was identified after screening of a cosmid gene library. Reverse transcription-PCR revealed that its expression was induced by benzoate; the product was heterologously expressed and isolated. Both wild-type and recombinant GDH(Geo) catalyzed the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA at similar rates. In contrast, recombinant GDH(Des) catalyzed only the dehydrogenation to glutaconyl-CoA. The latter compound was decarboxylated subsequently to crotonyl-CoA by the addition of membrane extracts from cells grown on benzoate in the presence of 20 mM NaCl. All GDH enzymes were purified as homotetramers of a 43- to 44-kDa subunit and contained 0.6 to 0.7 flavin adenine dinucleotides (FADs)/monomer. The kinetic properties for glutaryl-CoA conversion were as follows: for GDH(Geo), the K(m) was 30 +/- 2 microM and the V(max) was 3.2 +/- 0.2 micromol min(-1) mg(-1), and for GDH(Des), the K(m) was 52 +/- 5 microM and the V(max) was 11 +/- 1 micromol min(-1) mg(-1). GDH(Des) but not GDH(Geo) was inhibited by glutaconyl-CoA. Highly conserved amino acid residues that were proposed to be specifically involved in the decarboxylation of the intermediate glutaconyl-CoA were identified in GDH(Geo) but are missing in GDH(Des). The differential use of energy-yielding/energy-demanding enzymatic processes in anaerobic bacteria that degrade aromatic compounds is discussed in view of phylogenetic relationships and constraints of overall energy metabolism. PMID:19395484

  18. The Effects of Benthic Organic Matter Quality on Aerobic and Anaerobic Sediment Metabolism in West Falmouth Harbor

    E-print Network

    Vallino, Joseph J.

    , respectively. Anaerobic respiration rates were approximately two orders of magnitude lower than aerobic ratesThe Effects of Benthic Organic Matter Quality on Aerobic and Anaerobic Sediment Metabolism in West 02543 #12;Abstract Carbon quality, rates of respiration, and rates of dissolved inorganic nitrogen (DIN

  19. Comparison of endogenous metabolism during long-term anaerobic starvation of nitrite/nitrate cultivated denitrifying phosphorus removal sludges.

    PubMed

    Wang, Yayi; Zhou, Shuai; Wang, Hong; Ye, Liu; Qin, Jian; Lin, Ximao

    2015-01-01

    Denitrifying phosphorus removal (DPR) by denitrifying phosphorus-accumulating organisms (DPAOs) is a promising approach for reducing energy and carbon usage. However, influent fluctuations or interruptions frequently expose the DPAOs biomass to starvation conditions, reducing biomass activity and amount, and ultimately degrading the performance of DPR. Therefore, a better understanding of the endogenous metabolism and recovery ability of DPAOs is urgently required. In the present study, anaerobic starvation (12 days) and recovery were investigated in nitrite- and nitrate-cultivated DPAOs at 20 ± 1 °C. The cell decay rates in nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were 0.008 day?¹ and 0.007 day?¹, respectively, being 64% and 68% lower than those of nitrate-DPAOs sludges. Nitrite-DPAOs sludges also recovered more rapidly than nitrate-DPAOs sludge after 12 days of starvation. The maintenance energy of nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were approximately 31% and 34% lower, respectively, than those of nitrate-DPAOs sludges. Glycogen and polyphosphate (poly-P) sequentially served as the main maintenance energy sources in both nitrite-and nitrate-DPAOs sludges. However, the transformation pathway of the intracellular polymers during starvation differed between them. Nitrate-DPAOs sludge used extracellular polymeric substances (EPS) (mainly polysaccharides) as an additional maintenance energy source during the first 3 days of starvation. During this phase, EPS appeared to contribute to 19-27% of the ATP production in nitrate-DPAOs, but considerably less to the cell maintenance of nitrite-DPAOs. The high resistance of nitrite-DPAOs to starvation might be attributable to frequent short-term starvation and exposure to toxic substances such as nitrite/free nitrous acids in the parent nitrite-fed reactor. The strong resistance of nitrite-DPAOs sludge to anaerobic starvation may be exploited in P removal by shortcut denitrification processes. PMID:25462744

  20. Exercise- and hypoxia-induced anaerobic metabolism and recovery: a student laboratory exercise using teleost fish

    NSDL National Science Digital Library

    B B Rees (University of New Orleans Biological Sciences)

    2009-03-01

    Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory exercise developed as part of an upper-level vertebrate physiology class that demonstrates the effects of exercise and hypoxia exposure on blood lactate in fish and the subsequent decrease in lactate during recovery. Typically, the results obtained by students demonstrate that both treatments cause significant increases in blood lactate concentrations (two to three times higher than control values) that decrease back to normal values within 3 h of recovery under normoxia. The procedures described are generally applicable to other fish species and provide an alternative to using humans or other mammalian species to investigate anaerobic metabolism.

  1. Metabolism of tannin-protein complex by facultatively anaerobic bacteria isolated from koala feces

    Microsoft Academic Search

    Ro Osawa; Terry P. Walsh; Steven J. Cork

    1993-01-01

    The metabolic pathways involved in degradation of tannin-protein complex (T-PC) were investigated in various facultatively anaerobic bacteria, with specific reference to fecal isolates from the koala including T-PC-degrading enterobacteria (T-PCDE),Streptococcus bovis, Klebsiella pneumoniae, andK. oxytoca. It was demonstrated that T-PCDE andS. bovis biotype I were capable of degrading protein complexed with gallotannin (a hydrolyzable tannin), but not that complexed with

  2. Composite chemical wastewater treatment by biofilm configured periodic discontinuous batch process operated in anaerobic metabolic function

    Microsoft Academic Search

    S. Venkata Mohan; N. Chandrasekhara Rao; P. N. Sarma

    2007-01-01

    Biofilm configured system with sequencing\\/periodic discontinuous batch mode operation was studied in anaerobic metabolic function for the treatment of composite chemical wastewater (low-biodegradable [low BOD\\/COD ratio ?0.31] and sulfate content, 1.75g\\/l). Inert stone chips were used as biofilm supporting material. Reactor was operated with a total cycle period of 24h (FILL: 15min; REACT (aeration with recirculation): 23h; SETTLE: 30min; DECANT:

  3. Resistance to freshwater exposure in White Sea Littorina spp. I: Anaerobic metabolism and energetics

    Microsoft Academic Search

    I. M. Sokolova; C. Bock; H.-O. Pörtner

    2000-01-01

    Anaerobic metabolism and changes in the osmotic concentration of extravisceral fluid were studied in the White Sea periwinkles\\u000a (Littorina littorea, Littorina saxatilis and Littorina obtusata) during freshwater exposure. Resistance to hypoosmotic stress increased in the order: L. obtusata? Our data suggest that osmotic shock is not a primary reason for mortality of the periwinkles under these conditions. During\\u000a environmental anaerobiosis,

  4. Effects of pelagic food web structure and nutrient concentration on anaerobic methane metabolism in lake sediments

    Microsoft Academic Search

    Anna Rych?a; Peter Casper; Peter Kasprzak

    Although anaerobic metabolism in lake sediments is strongly related to organic material from the trophogenic layer, little\\u000a is known about the role of food web structure in this respect. We tested the influence of planktivorous fish (treatments with\\u000a or without fish, ±F) and nutrients (treatments with or without fertilization, ±N) on chlorophyll a, zooplankton, sedimentation\\u000a of particulate organic carbon (POC),

  5. Energy transduction by anaerobic ferric iron respiration in Thiobacillus ferrooxidans

    SciTech Connect

    Pronk, J.T.; Liem, K.; Bos, P.; Kuenen, J.G. (Delft Univ. of Technology (Netherlands))

    1991-07-01

    Formate-grown cells of the obligately chemolithoautotrophic acidophile Thiobacillus ferrooxidans were capable of formate- and elemental sulfur-dependent reduction of ferric iron under anaerovic conditions. Under aerobic conditions, both oxygen and ferric iron could be simultaneously used as electron acceptors. To investigate whether anaerobic ferric iron respiration by T. ferrooxidans is an energy-transducing process, uptake of amino acids was studied. Glycine uptake by starved cells did not occur in the absence of an electron donor, neither under aerobic conditions nor under anaerobic conditions. Uptake of glycine could be driven by formate- and ferrous iron-dependent oxygen uptake. Under anaerobic conditions, ferric iron respiration with the electron donors formate and elemental sulfur could energize glycine uptake. Glycine uptake was inhibited by the uncoupler 2,4-dinitrophenol. The results indicate that anaerobic ferric iron respiration can contribute to the energy budget of T. ferrooxidans.

  6. Resistance to freshwater exposure in White Sea Littorina spp. I: Anaerobic metabolism and energetics.

    PubMed

    Sokolova, I M; Bock, C; Pörtner, H O

    2000-03-01

    Anaerobic metabolism and changes in the osmotic concentration of extravisceral fluid were studied in the White Sea periwinkles (Littorina littorea, Littorina saxatilis and Littorina obtusata) during freshwater exposure. Resistance to hypoosmotic stress increased in the order: L. obtusata < L. saxatilis < L. littorea. Our data suggest that osmotic shock is not a primary reason for mortality of the periwinkles under these conditions. During environmental anaerobiosis, considerable succinate accumulation (up to 10(-19) micromol g(-1) wet weight), and depletion of phosphagen and ATP pools were found in the studied species. Other metabolic end products (alanopine, strombine, lactate, acetate or propionate) were not detected. Succinate accumulation and net ATP breakdown were the fastest in the least resistant species, L. obtusata, and slowest in the most resistant, L. littorea. Rate of ATP turnover decreased during freshwater exposure in L. littorea and L. saxatilis, but not in L. obtusata. Our data suggest that differential resistance of three studied Littorina spp. to extreme hypoosmotic stress may be related to their different abilities to reduce metabolic rate and ATP turnover during sustained anoxia. Species-specific variations in anaerobic capacity of Littorina spp. are discussed in relation to their vertical distribution, size and ecology. PMID:10791569

  7. Total solids content: a key parameter of metabolic pathways in dry anaerobic digestion

    PubMed Central

    2013-01-01

    Background In solid-state anaerobic digestion (AD) bioprocesses, hydrolytic and acidogenic microbial metabolisms have not yet been clarified. Since these stages are particularly important for the establishment of the biological reaction, better knowledge could optimize the process performances by process parameters adjustment. Results This study demonstrated the effect of total solids (TS) content on microbial fermentation of wheat straw with six different TS contents ranging from wet to dry conditions (10 to 33% TS). Three groups of metabolic behaviors were distinguished based on wheat straw conversion rates with 2,200, 1,600, and 1,400 mmol.kgVS-1 of fermentative products under wet (10 and 14% TS), dry (19 to 28% TS), and highly dry (28 to 33% TS) conditions, respectively. Furthermore, both wet and dry fermentations showed acetic and butyric acid metabolisms, whereas a mainly butyric acid metabolism occurred in highly dry fermentation. Conclusion Substrate conversion was reduced with no changes of the metabolic pathways until a clear limit at 28% TS content, which corresponded to the threshold value of free water content of wheat straw. This study suggested that metabolic pathways present a limit of TS content for high-solid AD. PMID:24261971

  8. Cellulose Digestion and Metabolism Induced Biocatalytic Transitions in Anaerobic Microbial Ecosystems

    PubMed Central

    Yamazawa, Akira; Iikura, Tomohiro; Morioka, Yusuke; Shino, Amiu; Ogata, Yoshiyuki; Date, Yasuhiro; Kikuchi, Jun

    2013-01-01

    Anaerobic digestion of highly polymerized biomass by microbial communities present in diverse microbial ecosystems is an indispensable metabolic process for biogeochemical cycling in nature and for industrial activities required to maintain a sustainable society. Therefore, the evaluation of the complicated microbial metabolomics presents a significant challenge. We here describe a comprehensive strategy for characterizing the degradation of highly crystallized bacterial cellulose (BC) that is accompanied by metabolite production for identifying the responsible biocatalysts, including microorganisms and their metabolic functions. To this end, we employed two-dimensional solid- and one-dimensional solution-state nuclear magnetic resonance (NMR) profiling combined with a metagenomic approach using stable isotope labeling. The key components of biocatalytic reactions determined using a metagenomic approach were correlated with cellulose degradation and metabolic products. The results indicate that BC degradation was mediated by cellulases that contain carbohydrate-binding modules and that belong to structural type A. The degradation reactions induced the metabolic dynamics of the microbial community and produced organic compounds, such as acetic acid and propionic acid, mainly metabolized by clostridial species. This combinatorial, functional and structural metagenomic approach is useful for the comprehensive characterization of biomass degradation, metabolic dynamics and their key components in diverse ecosystems. PMID:24958386

  9. An in Vivo 13C NMR Analysis of the Anaerobic Yeast Metabolism of 1-13C-Glucose

    Microsoft Academic Search

    Brent J. Giles; Zenziwe Matsche; Ryan D. Egeland; Ryan A. Reed; Scott S. Morioka; Richard L. Taber

    1999-01-01

    A biochemistry laboratory experiment that studies the dynamics of the anaerobic yeast metabolism of 1-13C-D-glucose via NMR is described. Fleischmann's Active Dry yeast, under anaerobic conditions, produces primarily 2-13C-ethanol and some 1-13C-glycerol as end products. An experiment is described in which the yeast is subjected to osmotic shock from an increasing sodium chloride concentration. Under these conditions, the yeast increases

  10. Anaerobic citrate metabolism and its regulation in enterobacteria

    Microsoft Academic Search

    M. Bott

    1997-01-01

    Several species of enterobacteria are able to utilize citrate as carbon and energy source. Under oxic conditions in the presence\\u000a of a functional tricarboxylic acid cycle, growth on this compound solely depends on an appropriate transport system. During\\u000a anaerobiosis, when 2-oxoglutarate dehydrogenase is repressed, some species such as Klebsiella pneumoniae and Salmonella typhimurium, but not Escherichia coli, are capable of

  11. Phenylphosphate Synthase: a New Phosphotransferase Catalyzing the First Step in Anaerobic Phenol Metabolism in Thauera aromatica

    PubMed Central

    Schmeling, Sirko; Narmandakh, Ariun; Schmitt, Oliver; Gad'on, Nasser; Schühle, Karola; Fuchs, Georg

    2004-01-01

    The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via para-carboxylation of phenol (biological Kolbe-Schmitt carboxylation). In the first step, phenol is converted to phenylphosphate which is then carboxylated to 4-hydroxybenzoate in the second step. Phenylphosphate formation is catalyzed by the novel enzyme phenylphosphate synthase, which was studied. Phenylphosphate synthase consists of three proteins whose genes are located adjacent to each other on the phenol operon and were overproduced in Escherichia coli. The promoter region and operon structure of the phenol gene cluster were investigated. Protein 1 (70 kDa) resembles the central part of classical phosphoenolpyruvate synthase which contains a conserved histidine residue. It catalyzes the exchange of free [14C]phenol and the phenol moiety of phenylphosphate but not the phosphorylation of phenol. Phosphorylation of phenol requires protein 1, MgATP, and another protein, protein 2 (40 kDa), which resembles the N-terminal part of phosphoenol pyruvate synthase. Proteins 1 and 2 catalyze the following reaction: phenol + MgATP + H2O?phenylphosphate + MgAMP + orthophosphate. The phosphoryl group in phenylphosphate is derived from the ?-phosphate group of ATP. The free energy of ATP hydrolysis obviously favors the trapping of phenol (Km, 0.04 mM), even at a low ambient substrate concentration. The reaction is stimulated severalfold by another protein, protein 3 (24 kDa), which contains two cystathionine-?-synthase domains of unknown function but does not show significant overall similarity to known proteins. The molecular and catalytic features of phenylphosphate synthase resemble those of phosphoenolpyruvate synthase, albeit with interesting modifications. PMID:15547277

  12. Aerobic and anaerobic energy expenditure during rest and activity in montane Bufo b. boreas and Rana pipiens

    Microsoft Academic Search

    Cynthia Carey

    1979-01-01

    The relations of standard and active aerobic and anaerobic metabolism and heart rate to body temperature (Tb) were measured in montane groups of Bufo b. boreas and Rana pipiens maintained under field conditions. These amphibians experience daily variation of Tb over 30°C and 23°C, respectively (Carey, 1978). Standard and active aerobic and anaerobic metabolism, heart rate, aerobic and anaerobic scope

  13. Anaerobic digestion for energy production and environmental protection

    SciTech Connect

    Lettinga, G. [Agricultural Univ., Wageningen (Netherlands); Haandel, A.C. Vaan [Federal Univ. of Paraiba, Campina Grande (Brazil)

    1993-12-31

    Anaerobic digestion is the decomposition of complex molecules into simpler substances by micro-organisms in the absence of oxygen. Anaerobic digestion processes can be employed for resource conservation, for the production of biogas and other useful end products from biomass, and for environmental protection through waste and wastewater treatment. Modern high-rate anaerobic wastewater-treatment processes can effectively remove organic pollutants from wastewater at a cost far below that of conventional aerobic processes. These anaerobic wastewater treatment processes can also be profitably applied for the generation of biogas from energy crops such as sugarcane. In fact, these methods might even be an attractive alternative for the alcohol fermentation extensively employed in Brazil for the production of fuel alcohol from sugarcane. The potential of modern anaerobic processes for this purpose has not yet been widely recognized. This paper describes the principles and use of these processes and demonstrates their prospects for producing energy from sugarcane (1) by treating vinasse, the wastewater generated during the production of ethanol from sugarcane, and (2) as a direct method for producing biogas from sugarcane juice.

  14. Metagenomic Insights into Anaerobic Metabolism along an Arctic Peat Soil Profile

    PubMed Central

    Lipson, David A.; Haggerty, John Matthew; Srinivas, Archana; Raab, Theodore K.; Sathe, Shashank; Dinsdale, Elizabeth A.

    2013-01-01

    A metagenomic analysis was performed on a soil profile from a wet tundra site in northern Alaska. The goal was to link existing biogeochemical knowledge of the system with the organisms and genes responsible for the relevant metabolic pathways. We specifically investigated how the importance of iron (Fe) oxides and humic substances (HS) as terminal electron acceptors in this ecosystem is expressed genetically, and how respiratory and fermentative processes varied with soil depth into the active layer and into the upper permafrost. Overall, the metagenomes reflected a microbial community enriched in a diverse range of anaerobic pathways, with a preponderance of known Fe reducing species at all depths in the profile. The abundance of sequences associated with anaerobic metabolic processes generally increased with depth, while aerobic cytochrome c oxidases decreased. Methanogenesis genes and methanogen genomes followed the pattern of CH4 fluxes : they increased steeply with depth into the active layer, but declined somewhat over the transition zone between the lower active layer and the upper permafrost. The latter was relatively enriched in fermentative and anaerobic respiratory pathways. A survey of decaheme cytochromes (MtrA, MtrC and their homologs) revealed that this is a promising approach to identifying potential reducers of Fe(III) or HS, and indicated a possible role for Acidobacteria as Fe reducers in these soils. Methanogens appear to coexist in the same layers, though in lower abundance, with Fe reducing bacteria and other potential competitors, including acetogens. These observations provide a rich set of hypotheses for further targeted study. PMID:23741360

  15. Hydrodynamic chronoamperometry for probing kinetics of anaerobic microbial metabolism – case study of Faecalibacterium prausnitzii

    PubMed Central

    Prévoteau, Antonin; Geirnaert, Annelies; Arends, Jan B.A.; Lannebère, Sylvain; Van de Wiele, Tom; Rabaey, Korneel

    2015-01-01

    Monitoring in vitro the metabolic activity of microorganisms aids bioprocesses and enables better understanding of microbial metabolism. Redox mediators can be used for this purpose via different electrochemical techniques that are either complex or only provide non-continuous data. Hydrodynamic chronoamperometry using a rotating disc electrode (RDE) can alleviate these issues but was seldom used and is poorly characterized. The kinetics of Faecalibacterium prausnitzii A2-165, a beneficial gut microbe, were determined using a RDE with riboflavin as redox probe. This butyrate producer anaerobically ferments glucose and reduces riboflavin whose continuous monitoring on a RDE provided highly accurate kinetic measurements of its metabolism, even at low cell densities. The metabolic reaction rate increased linearly over a broad range of cell concentrations (9?×?104 to 5?×?107 cells.mL?1). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM?=?6??M; kcat?=?5.3×105?s?1, at 37?°C) and glucose (KM?=?6??M; kcat?=?2.4?×?105?s?1). The short temporal resolution allows continuous monitoring of fast cellular events such as kinetics inhibition with butyrate. Furthermore, we detected for the first time riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum. The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution. PMID:26127013

  16. Comparative genomic analysis of dha regulon and related genes for anaerobic glycerol metabolism in bacteria.

    PubMed

    Sun, Jibin; van den Heuvel, Joop; Soucaille, Philippe; Qu, Yinbo; Zeng, An-Ping

    2003-01-01

    The dihydroxyacetone (dha) regulon of bacteria encodes genes for the anaerobic metabolism of glycerol. In this work, genomic data are used to analyze and compare the dha regulon and related genes in different organisms in silico with respect to gene organization, sequence similarity, and possible functions. Database searches showed that among the organisms, the genomes of which have been sequenced so far, only two, i.e., Klebsiella pneumoniae MGH 78578 and Clostridium perfringens contain a complete dha regulon bearing all known enzymes. The components and their organization in the dha regulon of these two organisms differ considerably from each other and also from the previously partially sequenced dha regulons in Citrobacter freundii, Clostridium pasteurianum, and Clostridium butyricum. Unlike all of the other organisms, genes for the oxidative and reductive pathways of anaerobic glycerol metabolism in C. perfringens are located in two separate organization units on the chromosome. Comparisons of deduced protein sequences of genes with similar functions showed that the dha regulon components in K. pneumoniae and C. freundii have high similarities (80-95%) but lower similarities to those of the Clostridium species (30-80%). Interestingly, the protein sequence similarities among the dha genes of the Clostridium species are in many cases even lower than those between the Clostridium species and K. pneumoniae or C. freundii, suggesting two different types of dha regulon in the Clostridium species studied. The in silico reconstruction and comparison of dha regulons revealed several new genes in the microorganisms studied. In particular, a novel dha kinase that is phosphoenolpyruvate-dependent is identified and experimentally confirmed for K. pneumoniae in addition to the known ATP-dependent dha kinase. This finding gives new insights into the regulation of glycerol metabolism in K. pneumoniae and explains some hitherto not well understood experimental observations. PMID:12675558

  17. Fermentative metabolism of substituted monoaromatic compounds by a bacterial community from anaerobic sediments

    Microsoft Academic Search

    Jean-Pierre Kaiser; Kurt W. Hanselmann

    1982-01-01

    An anaerobic microbial community containing 4 to 5 different populations capable of degrading syringic acid completely to CH4 and CO2 was enriched from freshwater lake sediments. The community can be maintained with syringic acid as sole carbon- and energy source in a defined mineral medium. Syringic acid is converted stoichiometrically according to \\u000a$$C_9 H_{10} O_5 + 4H_2 O \\\\to 4{\\\\raise0.5ex\\\\hbox{$\\\\scriptstyle

  18. Metabolism of polyethylene glycol by two anaerobic bacteria, Desulfovibrio desulfuricans and a Bacteroides sp.

    PubMed Central

    Dwyer, D F; Tiedje, J M

    1986-01-01

    Two anaerobic bacteria were isolated from polyethylene glycol (PEG)-degrading, methanogenic, enrichment cultures obtained from a municipal sludge digester. One isolate, identified as Desulfovibrio desulfuricans (strain DG2), metabolized oligomers ranging from ethylene glycol (EG) to tetraethylene glycol. The other isolate, identified as a Bacteroides sp. (strain PG1), metabolized diethylene glycol and polymers of PEG up to an average molecular mass of 20,000 g/mol [PEG 20000; HO-(CH2-CH2-O-)nH]. Both strains produced acetaldehyde as an intermediate, with acetate, ethanol, and hydrogen as end products. In coculture with a Methanobacterium sp., the end products were acetate and methane. Polypropylene glycol [HO-(CH2-CH2-CH2-O-)nH] was not metabolized by either bacterium, and methanogenic enrichments could not be obtained on this substrate. Cell extracts of both bacteria dehydrogenated EG, PEGs up to PEG 400 in size, acetaldehyde, and other mono- and dihydroxylated compounds. Extracts of Bacteroides strain PG1 could not dehydrogenate long polymers of PEG (greater than or equal to 1,000 g/mol), but the bacterium grew with PEG 1000 or PEG 20000 as a substrate and therefore possesses a mechanism for PEG depolymerization not present in cell extracts. In contrast, extracts of D. desulfuricans DG2 dehydrogenated long polymers of PEG, but whole cells did not grow with these polymers as substrates. This indicated that the bacterium could not convert PEG to a product suitable for uptake. PMID:3777930

  19. Ontogenetic effects on aerobic and anaerobic metabolism during jumping in the American locust, Schistocerca americana.

    PubMed

    Kirkton, Scott D; Niska, Jared A; Harrison, Jon F

    2005-08-01

    Developing vertebrates increase both their locomotory power output and endurance due to ontogenetic improvements in anaerobic and aerobic metabolic capacities. Do similar patterns hold for insect locomotion, or do longer tracheal lengths create problems for oxygen delivery in older animals? We forced developing American locust grasshoppers (Schistocerca americana) to jump repeatedly and examined the effect of development on power output, endurance, lactate concentration, oxygen consumption and the oxygen sensitivity of jump performance. As previously shown, power outputs, relative leg lengths and leg cuticular content increased with age. A key finding of this study is that both lactate concentration and aerobic metabolic rate of the jumping muscle increase with age, explaining how the increased leg cuticular stiffness can result in increased power output. After two minutes of jumping, grasshoppers rely completely on aerobic ATP production. The rise in mass-specific, active aerobic metabolic rates with age indicates that problems with longer tracheae can be overcome; however, the reduced endurance, higher lactate concentrations and increased oxygen sensitivity of locomotory performance in older animals indicate that larger/older grasshoppers have smaller safety margins for oxygen delivery during hopping. PMID:16043604

  20. Metabolic adaptation to sugar/O2 deficiency for anaerobic germination and seedling growth in rice.

    PubMed

    Lee, Kuo-Wei; Chen, Peng Wen; Yu, Su-May

    2014-10-01

    Rice is characterized by a broad range of metabolic and morphological adaptations to flooding, such as germination and mobilization of stored nutrients under submergence until seedlings reach the water surface to carry out photosynthesis, and sustainable growth of mature plants for long durations under partial submergence. The underlying mechanisms of the molecular basis of adaptation to anaerobic germination and seedling growth in rice are being uncovered. Induction of an ensemble of hydrolases to mobilize endosperm nutrient reserves is one of the key factors for successful germination and coleoptile elongation in rice under submergence. To compensate for reduced efficiency of Tricarboxylic Acid cycle and oxidative respiration in mitochondria under O2 deficient conditions, ?-amylases play a central role in the hydrolysis of starch to provide sugar substrates for glycolysis and alcohol fermentation for generating ATP. We review the progress on the molecular mechanism regulating ?-amylase expression that involves the integration of signals generated by the hormone gibberellin (GA), sugar starvation and O2 deprivation that results in germination and sustainable seedling growth in rice under anaerobic conditions. Comparisons are also made between dicots and monocots for the molecular mechanism of induction of genes involved in alcohol fermentation and sugar/O2 deficiency sensing system. PMID:24575721

  1. Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

    PubMed

    Wikandari, Rachma; Sari, Noor Kartika; A'yun, Qurrotul; Millati, Ria; Cahyanto, Muhammad Nur; Niklasson, Claes; Taherzadeh, Mohammad J

    2015-02-01

    Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., ?-hexalactone and ?-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of ?-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of ?-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, ?-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L. PMID:25416476

  2. Genes Involved in Anaerobic Metabolism of Phenol in the Bacterium Thauera aromatica

    PubMed Central

    Breinig, Sabine; Schiltz, Emile; Fuchs, Georg

    2000-01-01

    Genes involved in the anaerobic metabolism of phenol in the denitrifying bacterium Thauera aromatica have been studied. The first two committed steps in this metabolism appear to be phosphorylation of phenol to phenylphosphate by an unknown phosphoryl donor (“phenylphosphate synthase”) and subsequent carboxylation of phenylphosphate to 4-hydroxybenzoate under release of phosphate (“phenylphosphate carboxylase”). Both enzyme activities are strictly phenol induced. Two-dimensional gel electrophoresis allowed identification of several phenol-induced proteins. Based on N-terminal and internal amino acid sequences of such proteins, degenerate oligonucleotides were designed to identify the corresponding genes. A chromosomal DNA segment of about 14 kbp was sequenced which contained 10 genes transcribed in the same direction. These are organized in two adjacent gene clusters and include the genes coding for five identified phenol-induced proteins. Comparison with sequences in the databases revealed the following similarities: the gene products of two open reading frames (ORFs) are each similar to either the central part and N-terminal part of phosphoenolpyruvate synthases. We propose that these ORFs are components of the phenylphosphate synthase system. Three ORFs showed similarity to the ubiD gene product, 3-octaprenyl-4-hydroxybenzoate carboxy lyase; UbiD catalyzes the decarboxylation of a 4-hydroxybenzoate analogue in ubiquinone biosynthesis. Another ORF was similar to the ubiX gene product, an isoenzyme of UbiD. We propose that (some of) these four proteins are involved in the carboxylation of phenylphosphate. A 700-bp PCR product derived from one of these ORFs cross-hybridized with DNA from different Thauera and Azoarcus strains, even from those which have not been reported to grow with phenol. One ORF showed similarity to the mutT gene product, and three ORFs showed no strong similarities to sequences in the databases. Upstream of the first gene cluster, an ORF which is transcribed in the opposite direction codes for a protein highly similar to the DmpR regulatory protein of Pseudomonas putida. DmpR controls transcription of the genes of aerobic phenol metabolism, suggesting a similar regulation of anaerobic phenol metabolism by the putative regulator. PMID:11004186

  3. An in Vivo 13C NMR Analysis of the Anaerobic Yeast Metabolism of 1-13C-Glucose

    NASA Astrophysics Data System (ADS)

    Giles, Brent J.; Matsche, Zenziwe; Egeland, Ryan D.; Reed, Ryan A.; Morioka, Scott S.; Taber, Richard L.

    1999-11-01

    A biochemistry laboratory experiment that studies the dynamics of the anaerobic yeast metabolism of 1-13C-D-glucose via NMR is described. Fleischmann's Active Dry yeast, under anaerobic conditions, produces primarily 2-13C-ethanol and some 1-13C-glycerol as end products. An experiment is described in which the yeast is subjected to osmotic shock from an increasing sodium chloride concentration. Under these conditions, the yeast increases the ratio of glycerol to ethanol. The experiment can be accomplished in a single laboratory period.

  4. Kinetics of butyrate, acetate, and hydrogen metabolism in a thermophilic, anaerobic, butyrate-degrading triculture.

    PubMed

    Ahring, B K; Westermann, P

    1987-02-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, K(m), for butyrate, acetate, and dissolved hydrogen were 76 muM, 0.4 mM, and 8.5 muM, respectively. Butyrate and hydrogen were metabolized to a concentration of less than 1 muM, whereas acetate uptake usually ceased at a concentration of 25 to 75 muM, indicating a threshold level for acetate uptake. No significant differences in K(m) values for butyrate degradation were found between chemostat- and batch-grown tricultures, although the maximum growth rate was somewhat higher in the batch cultures in which the medium was supplemented with yeast extract. Acetate utilization was found to be the rate-limiting reaction for complete degradation of butyrate to methane and carbon dioxide in continuous culture. Increasing the dilution rate resulted in a gradual accumulation of acetate. The results explain the low concentrations of butyrate and hydrogen normally found during anaerobic digestion and the observation that acetate is the first volatile fatty acid to accumulate upon a decrease in retention time or increase in organic loading of a digestor. PMID:16347293

  5. In situ detection of anaerobic alkane metabolites in subsurface environments.

    PubMed

    Agrawal, Akhil; Gieg, Lisa M

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contributing to modern-day detrimental effects such as oilfield souring, or may lead to more beneficial technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes) metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments. PMID:23761789

  6. Navigating wastewater energy recovery strategies: a life cycle comparison of anaerobic membrane bioreactor and conventional treatment systems with anaerobic digestion.

    PubMed

    Smith, Adam L; Stadler, Lauren B; Cao, Ling; Love, Nancy G; Raskin, Lutgarde; Skerlos, Steven J

    2014-05-20

    The objective of this study was to evaluate emerging anaerobic membrane bioreactor (AnMBR) technology in comparison with conventional wastewater energy recovery technologies. Wastewater treatment process modeling and systems analyses were combined to evaluate the conditions under which AnMBR may produce more net energy and have lower life cycle environmental emissions than high rate activated sludge with anaerobic digestion (HRAS+AD), conventional activated sludge with anaerobic digestion (CAS+AD), and an aerobic membrane bioreactor with anaerobic digestion (AeMBR+AD). For medium strength domestic wastewater treatment under baseline assumptions at 15 °C, AnMBR recovered 49% more energy as biogas than HRAS+AD, the most energy positive conventional technology considered, but had significantly higher energy demands and environmental emissions. Global warming impacts associated with AnMBR were largely due to emissions of effluent dissolved methane. For high strength domestic wastewater treatment, AnMBR recovered 15% more net energy than HRAS+AD, and the environmental emissions gap between the two systems was reduced. Future developments of AnMBR technology in low energy fouling control, increased flux, and management of effluent methane emissions would make AnMBR competitive with HRAS+AD. Rapid advancements in AnMBR technology must continue to achieve its full economic and environmental potential as an energy recovery strategy for domestic wastewater. PMID:24742289

  7. Metabolism of toxic pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea) in ovine ruminal fluid under anaerobic conditions.

    PubMed Central

    Craig, A M; Latham, C J; Blythe, L L; Schmotzer, W B; O'Connor, O A

    1992-01-01

    The ability of ovine ruminal fluid to metabolize pyrrolizidine alkaloid (PA) from Senecio jacobaea under anaerobic conditions was evaluated. Four fistulated sheep fed PA served as individual sources of ruminal fluid, which was incubated in a defined minimal salts medium under two different anaerobic conditions, denitrifying and methanogenic. Anaerobic cultures amended with ovine ruminal fluids (20%), PA (100 micrograms/ml), and a defined minimal salts medium were monitored for a period of several days. These cultures revealed that while PA was not depleted in sterile, autoclaved controls or under denitrifying conditions, it was metabolized during periods of active methanogenesis under methanogenic conditions. In addition, samples of ruminal fluid were separated by differential centrifugation under anaerobic conditions, and the resultant supernatants were tested for their ability to metabolize PA as compared with those of the respective uncentrifuged control fluids. Uncentrifuged controls exhibited a PA depletion rate of -4.04 +/- 0.17 micrograms of PA per ml per h. Supernatants 1 (centrifuged at 41 x g for 2 min), 2 (centrifuged at 166 x g for 5 min), and 3 (centrifuged at 1,500 x g for 10 min) exhibited significantly slower depletion rates, with slopes of data representing -1.64 +/- 0.16, -1.44 +/- 0.16, and -1.48 +/- 0.16 micrograms of PA metabolized per ml per h, respectively, demonstrating no statistically significant difference among the supernatant cultures. Microscopic evaluations revealed that protozoa were present in the control whole ruminal fluid and to a lesser extent in supernatant 1, while supernatants 2 and 3 contained only bacteria.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1444382

  8. Probing the redox metabolism in the strictly anaerobic, extremely thermophilic, hydrogen-producing Caldicellulosiruptor saccharolyticus using amperometry

    Microsoft Academic Search

    Natalie Kostesha; Karin Willquist; Jenny Emneus; Ed W. J. van Niel

    2011-01-01

    Changes in the redox metabolism in the anaerobic, extremely thermophilic, hydrogen-forming bacterium Caldicellulosiruptor saccharolyticus were probed for the first time in vivo using mediated amperometry with ferricyanide as a thermotolerant external mediator.\\u000a Clear differences in the intracellular electron flow were observed when cells were supplied with different carbon sources.\\u000a A higher electrochemical response was detected when cells were supplied with

  9. Amino and organic acid metabolism during anaerobic ammonium assimilation in a green alga

    SciTech Connect

    Vanlerberghe, G.C.; Turpin, D.H. (Queen's Univ., Kingston, Ontario (Canada))

    1989-04-01

    Chemostat grown, N-limited cells of Selenastrum minutum are able to assimilate NH{sub 4}{sup +} anaerobically in the dark. These cells maintain partial oxidative TCA cycle activity to supply alpha-ketoglutarate for amino acid synthesis. Evidence for this includes increased rates of dark carbon fixation and TCA cycle CO{sub 2} efflux upon NH{sub 4}{sup +} supply, as well as incorporation of radiolabel into the alpha-carboxyl carbon of glutamic acid when these cells are pulsed with H{sup 14}CO{sub 3}{sup {minus}}. Metabolite pool size and radiolabel data indicates that there is active amino acid synthesis in these cells. Clearly, metabolism must be altered to accommodate the regeneration of NAD{sup +} as typical fermentative pathways cannot support active oxidative TCA cycle carbon flow. Two strategies which may be important in this regard are the operation of a reductive pathway from PEP to OAA, malate and succinate and the biosynthesis of amino acids with high nitrogen to carbon ratios.

  10. Complete Genome of Ignavibacterium album, a Metabolically Versatile, Flagellated, Facultative Anaerobe from the Phylum Chlorobi

    PubMed Central

    Liu, Zhenfeng; Frigaard, Niels-Ulrik; Vogl, Kajetan; Iino, Takao; Ohkuma, Moriya; Overmann, Jörg; Bryant, Donald A.

    2012-01-01

    Prior to the recent discovery of Ignavibacterium album (I. album), anaerobic photoautotrophic green sulfur bacteria (GSB) were the only members of the bacterial phylum Chlorobi that had been grown axenically. In contrast to GSB, sequence analysis of the 3.7-Mbp genome of I. album shows that this recently described member of the phylum Chlorobi is a chemoheterotroph with a versatile metabolism. I. album lacks genes for photosynthesis and sulfur oxidation but has a full set of genes for flagella and chemotaxis. The occurrence of genes for multiple electron transfer complexes suggests that I. album is capable of organoheterotrophy under both oxic and anoxic conditions. The occurrence of genes encoding enzymes for CO2 fixation as well as other enzymes of the reductive TCA cycle suggests that mixotrophy may be possible under certain growth conditions. However, known biosynthetic pathways for several amino acids are incomplete; this suggests that I. album is dependent upon on exogenous sources of these metabolites or employs novel biosynthetic pathways. Comparisons of I. album and other members of the phylum Chlorobi suggest that the physiology of the ancestors of this phylum might have been quite different from that of modern GSB. PMID:22661972

  11. Oxygen Sensing and Signal Transduction in Metabolic Defense Against Hypoxia: Lessons from Vertebrate Facultative Anaerobes

    Microsoft Academic Search

    P. W. Hochachka; S. C. Land; L. T. Buck

    1997-01-01

    Earlier studies identified two main defense strategies against hypoxia in hypoxia tolerant animals: (1) reduction in energy turnover, and (2) improved energetic efficiency of those metabolic processes that remain. We used two model systems from the highly anoxia-tolerant aquatic turtle: (1) tissue slices of brain cortex (to probe cell level electrophysiological responses to oxygen limitation), and (2) isolated liver hepatocytes

  12. Engineering an anaerobic metabolic regime in Pseudomonas putida KT2440 for the anoxic biodegradation of 1,3-dichloroprop-1-ene.

    PubMed

    Nikel, Pablo I; de Lorenzo, Víctor

    2013-01-01

    Pseudomonas putida KT2440, a microbial cell factory of reference for industrial whole-cell biocatalysis, is unable to support biochemical reactions that occur under anoxic conditions, limiting its utility for a large number of relevant biotransformations. Unlike (facultative) anaerobes, P. putida resorts to NADH oxidation via an oxic respiratory chain and completely lacks a true fermentation metabolism. Therefore, it cannot achieve the correct balances of energy and redox couples (i.e., ATP/ADP and NADH/NAD(+)) that are required to sustain an O(2)-free lifestyle. To overcome this state of affairs, the acetate kinase (ackA) gene of the facultative anaerobe Escherichia coli and the pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adhB) genes of the aerotolerant Zymomonas mobilis were knocked-in to a wild-type P. putida strain. Biochemical and genetic assays showed that conditional expression of the entire enzyme set allowed the engineered bacteria to adopt an anoxic regime that maintained considerable metabolic activity. The resulting strain was exploited as a host for the heterologous expression of a 1,3-dichloroprop-1-ene degradation pathway recruited from Pseudomonas pavonaceae 170, enabling the recombinants to degrade this recalcitrant chlorinated compound anoxically. These results underscore the value of P. putida as a versatile agent for biotransformations able to function at progressively lower redox statuses. PMID:23149123

  13. Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in Thauera aromatica

    PubMed Central

    Schühle, Karola; Fuchs, Georg

    2004-01-01

    The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins with molecular masses of 54, 53, 18, and 10 kDa, whose genes are located adjacent to each other in the phenol gene cluster which codes for phenol-induced proteins. Three of the subunits (54, 53, and 10 kDa) were sufficient to catalyze the exchange of 14CO2 and the carboxyl group of 4-hydroxybenzoate but not phenylphosphate carboxylation. Phenylphosphate carboxylation was restored when the 18-kDa subunit was added. The following reaction model is proposed. The 14CO2 exchange reaction catalyzed by the three subunits of the core enzyme requires the fully reversible release of CO2 from 4-hydroxybenzoate with formation of a tightly enzyme-bound phenolate intermediate. Carboxylation of phenylphosphate requires in addition the 18-kDa subunit, which is thought to form the same enzyme-bound energized phenolate intermediate from phenylphosphate with virtually irreversible release of phosphate. The 54- and 53-kDa subunits show similarity to UbiD of Escherichia coli, which catalyzes the decarboxylation of a 4-hydroxybenzoate derivative in ubiquinone (ubi) biosynthesis. They also show similarity to components of various decarboxylases acting on aromatic carboxylic acids, such as 4-hydroxybenzoate or vanillate, whereas the 10-kDa subunit is unique. The 18-kDa subunit belongs to a hydratase/phosphatase protein family. Phenylphosphate carboxylase is a member of a new family of carboxylases/decarboxylases that act on phenolic compounds, use CO2 as a substrate, do not contain biotin or thiamine diphosphate, require K+ and a divalent metal cation (Mg2+or Mn2+) for activity, and are strongly inhibited by oxygen. PMID:15231788

  14. Metabolism of aniline under different anaerobic electron-accepting and nutritional conditions

    SciTech Connect

    De, M.A.; O'Connor, O.A.; Kosson, D.S. (Rutgers, The State Univ. of New Jersey, Piscataway, NJ (United States). Dept. of Chemical and Biochemical Engineering)

    1994-02-01

    The biodegradability of aniline was evaluated under two different anaerobic conditions, denitrifying and methanogenic. In addition, under denitrifying conditions, the influence of bicarbonate was studied. Anaerobic sewage digester sludge and estuarine sediment were used as heterogeneous sources of bacteria. Under anaerobic denitrifying conditions amended with bicarbonate, aniline was completely mineralized to CO[sub 2] and N[sub 2]. After an initial lag period, N[sub 2] recoveries of 74 and 100% were obtained for sludge and sediment cultures, respectively. Under anaerobic denitrifying conditions with no bicarbonate, aniline depletion was observed; however, stoichiometric quantities of N[sub 2] were not produced from mineralization and were in fact inhibited below background controls. Under methanogenic conditions, aniline concentration remained unchanged for > 31 weeks. A metabolite of aniline, 4-hydroxybenzoate, was detected in bicarbonate-amended denitrifying cultures.

  15. Anaerobic Sulfur Metabolism Coupled to Dissimilatory Iron Reduction in the Extremophile Acidithiobacillus ferrooxidans

    PubMed Central

    Osorio, Héctor; Mangold, Stefanie; Denis, Yann; Ñancucheo, Ivan; Esparza, Mario; Johnson, D. Barrie; Bonnefoy, Violaine; Dopson, Mark

    2013-01-01

    Gene transcription (microarrays) and protein levels (proteomics) were compared in cultures of the acidophilic chemolithotroph Acidithiobacillus ferrooxidans grown on elemental sulfur as the electron donor under aerobic and anaerobic conditions, using either molecular oxygen or ferric iron as the electron acceptor, respectively. No evidence supporting the role of either tetrathionate hydrolase or arsenic reductase in mediating the transfer of electrons to ferric iron (as suggested by previous studies) was obtained. In addition, no novel ferric iron reductase was identified. However, data suggested that sulfur was disproportionated under anaerobic conditions, forming hydrogen sulfide via sulfur reductase and sulfate via heterodisulfide reductase and ATP sulfurylase. Supporting physiological evidence for H2S production came from the observation that soluble Cu2+ included in anaerobically incubated cultures was precipitated (seemingly as CuS). Since H2S reduces ferric iron to ferrous in acidic medium, its production under anaerobic conditions indicates that anaerobic iron reduction is mediated, at least in part, by an indirect mechanism. Evidence was obtained for an alternative model implicating the transfer of electrons from S0 to Fe3+ via a respiratory chain that includes a bc1 complex and a cytochrome c. Central carbon pathways were upregulated under aerobic conditions, correlating with higher growth rates, while many Calvin-Benson-Bassham cycle components were upregulated during anaerobic growth, probably as a result of more limited access to carbon dioxide. These results are important for understanding the role of A. ferrooxidans in environmental biogeochemical metal cycling and in industrial bioleaching operations. PMID:23354702

  16. Anaerobic sulfur metabolism coupled to dissimilatory iron reduction in the extremophile Acidithiobacillus ferrooxidans.

    PubMed

    Osorio, Héctor; Mangold, Stefanie; Denis, Yann; Ñancucheo, Ivan; Esparza, Mario; Johnson, D Barrie; Bonnefoy, Violaine; Dopson, Mark; Holmes, David S

    2013-04-01

    Gene transcription (microarrays) and protein levels (proteomics) were compared in cultures of the acidophilic chemolithotroph Acidithiobacillus ferrooxidans grown on elemental sulfur as the electron donor under aerobic and anaerobic conditions, using either molecular oxygen or ferric iron as the electron acceptor, respectively. No evidence supporting the role of either tetrathionate hydrolase or arsenic reductase in mediating the transfer of electrons to ferric iron (as suggested by previous studies) was obtained. In addition, no novel ferric iron reductase was identified. However, data suggested that sulfur was disproportionated under anaerobic conditions, forming hydrogen sulfide via sulfur reductase and sulfate via heterodisulfide reductase and ATP sulfurylase. Supporting physiological evidence for H2S production came from the observation that soluble Cu(2+) included in anaerobically incubated cultures was precipitated (seemingly as CuS). Since H(2)S reduces ferric iron to ferrous in acidic medium, its production under anaerobic conditions indicates that anaerobic iron reduction is mediated, at least in part, by an indirect mechanism. Evidence was obtained for an alternative model implicating the transfer of electrons from S(0) to Fe(3+) via a respiratory chain that includes a bc(1) complex and a cytochrome c. Central carbon pathways were upregulated under aerobic conditions, correlating with higher growth rates, while many Calvin-Benson-Bassham cycle components were upregulated during anaerobic growth, probably as a result of more limited access to carbon dioxide. These results are important for understanding the role of A. ferrooxidans in environmental biogeochemical metal cycling and in industrial bioleaching operations. PMID:23354702

  17. Production of clean energy by anaerobic digestion of phytomass—New prospects for a global warming amelioration technology

    Microsoft Academic Search

    Tasneem Abbasi; S. A. Abbasi

    2010-01-01

    Anaerobic digestion of animal dung generated combustible gas – this fact has been known since over 130 years and has been gainfully utilized in generating clean energy in the form of methane-rich ‘biogas’. During 1970s it was found that aquatic weeds and other phytomass, if anaerobically digested, also produced similarly combustible ‘bio’ gas. It raised great hopes that anaerobic digestion

  18. Ibogaine affects brain energy metabolism.

    PubMed

    Paskulin, Roman; Jamnik, Polona; Zivin, Marko; Raspor, Peter; Strukelj, Borut

    2006-12-15

    Ibogaine is an indole alkaloid present in the root of the plant Tabernanthe iboga. It is known to attenuate abstinence syndrome in animal models of drug addiction. Since the anti-addiction effect lasts longer than the presence of ibogaine in the body, some profound metabolic changes are expected. The aim of this study was to investigate the effect of ibogaine on protein expression in rat brains. Rats were treated with ibogaine at 20 mg/kg body weight i.p. and subsequently examined at 24 and 72 h. Proteins were extracted from whole brain and separated by two-dimensional (2-D) electrophoresis. Individual proteins were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Enzymes of glycolysis and tricarboxylic acid (TCA) cycle namely glyceraldehyde-3-phosphate dehydrogenase, aldolase A, pyruvate kinase and malate dehydrogenase were induced. The results suggest that the remedial effect of ibogaine could be mediated by the change in energy availability. Since energy dissipating detoxification and reversion of tolerance to different drugs of abuse requires underlying functional and structural changes in the cell, higher metabolic turnover would be favourable. Understanding the pharmacodynamics of anti-addiction drugs highlights the subcellular aspects of addiction diseases, in addition to neurological and psychological perspectives. PMID:17054944

  19. Ontogenesis of catabolic and energy metabolism capacities during the embryonic development of spotted wolffish (Anarhichas minor).

    PubMed

    Desrosiers, Véronique; Le François, Nathalie R; Tveiten, Helge; Andreassen, Inger; Blier, Pierre U

    2008-06-01

    The catabolic and energy metabolism capacities during spotted wolffish (Anarhichas minor) embryogenesis were investigated. We assessed the embryo's ability to catabolize proteins (trypsin-like proteases) and lipids (triglyceride lipase) and examined the development of metabolic capacities using enzymatic assays: ability to use carbohydrates (pyruvate kinase), amino acids (aspartate aminotransferase) and fatty acids (hydroxyacyl-CoA dehydrogenase) for energy production, and aerobic (citrate synthase) and anaerobic (lactate dehydrogenase) energy production. Functional enzymatic systems were detected from the eyed stage (350 degree-days), except for fatty acids, which was detected from 540 degree-days. To compare the development of 1) aerobic and anaerobic pathways and 2) the capacity to mobilize the different energy substrates, enzymatic ratios were calculated. Anaerobic capacity appeared to increase at a significantly higher rate than the aerobic capacity. Ratios revealing the relative capacity to use specific energy substrates showed a significantly slower increase during development in the capacity to use carbohydrates than amino acids and fatty acids. The end of embryogenesis was characterized by a significant decrease in the use of carbohydrates for aerobic energy production but an increasing capacity to use amino acids. Egg survival as affected by the variability in metabolic parameters is discussed. PMID:18417396

  20. Submerged anaerobic membrane bioreactor for wastewater treatment and energy generation.

    PubMed

    Bornare, J B; Adhyapak, U S; Minde, G P; Kalyan Raman, V; Sapkal, V S; Sapkal, R S

    2015-01-01

    Compared with conventional wastewater treatment processes, membrane bioreactors (MBRs) offer several advantages including high biodegradation efficiency, excellent effluent quality and smaller footprint. However, it has some limitations on account of its energy intensive operation. In recent years, there has been growing interest in use of anaerobic membrane bioreactors (AnMBRs) due to their potential advantages over aerobic systems, which include low sludge production and energy generation in terms of biogas. The aim of this study was to evaluate the performance of a submerged AnMBR for the treatment of synthetic wastewater having 4,759 mg/l chemical oxygen demand (COD). The COD removal efficiency was over 95% during the performance evaluation study. Treated effluent with COD concentration of 231 mg/l was obtained for 25.5 hours hydraulic retention time. The obtained total organic carbon concentrations in feed and permeate were 1,812 mg/l and 89 mg/l, respectively. An average biogas generation and yield were 25.77 l/d and 0.36 m(3)/kg COD, respectively. Evolution of trans-membrane pressure (TMP) as a function of time was studied and an average TMP of 15 kPa was found suitable to achieve membrane flux of 12.17 l/(m(2)h). Almost weekly back-flow chemical cleaning of the membrane was found necessary to control TMP within the permissible limit of 20 kPa. PMID:26038930

  1. Simultaneous Involvement of a Tungsten-Containing Aldehyde:Ferredoxin Oxidoreductase and a Phenylacetaldehyde Dehydrogenase in Anaerobic Phenylalanine Metabolism

    PubMed Central

    Debnar-Daumler, Carlotta; Seubert, Andreas; Schmitt, Georg

    2014-01-01

    Anaerobic phenylalanine metabolism in the denitrifying betaproteobacterium Aromatoleum aromaticum is initiated by conversion of phenylalanine to phenylacetate, which is further metabolized via benzoyl-coenzyme A (CoA). The formation of phenylacetate is catalyzed by phenylalanine transaminase, phenylpyruvate decarboxylase, and a phenylacetaldehyde-oxidizing enzyme. The presence of these enzymes was detected in extracts of cells grown with phenylalanine and nitrate. We found that two distinct enzymes are involved in the oxidation of phenylacetaldehyde to phenylacetate, an aldehyde:ferredoxin oxidoreductase (AOR) and a phenylacetaldehyde dehydrogenase (PDH). Based on sequence comparison, growth studies with various tungstate concentrations, and metal analysis of the enriched enzyme, AOR was shown to be a tungsten-containing enzyme, necessitating specific cofactor biosynthetic pathways for molybdenum- and tungsten-dependent enzymes simultaneously. We predict from the genome sequence that most enzymes of molybdopterin biosynthesis are shared, while the molybdate/tungstate uptake systems are duplicated and specialized paralogs of the sulfur-inserting MoaD and the metal-inserting MoeA proteins seem to be involved in dedicating biosynthesis toward molybdenum or tungsten cofactors. We also characterized PDH biochemically and identified both NAD+ and NADP+ as electron acceptors. We identified the gene coding for the enzyme and purified a recombinant Strep-tagged PDH variant. The homotetrameric enzyme is highly specific for phenylacetaldehyde, has cooperative kinetics toward the substrate, and shows considerable substrate inhibition. Our data suggest that A. aromaticum utilizes PDH as the primary enzyme during anaerobic phenylalanine degradation, whereas AOR is not essential for the metabolic pathway. We hypothesize a function as a detoxifying enzyme if high aldehyde concentrations accumulate in the cytoplasm, which would lead to substrate inhibition of PDH. PMID:24214948

  2. Role of anaerobic bacteria in the metabolic welfare of the colonic mucosa in man

    Microsoft Academic Search

    W E Roediger

    1980-01-01

    Suspensions of isolated epithelial cells (colonocytes) from the human colon were used to assess utilisation of respiratory fuels which are normally available to the colonic mucosa in vivo. Cells were prepared from operative specimens of the ascending colon (seven) and descending colon (seven). The fuels that were used were the short chain fatty acid n-butyrate, produced only by anaerobic bacteria

  3. Metabolic engineering of a xylose-isomerase-expressing Saccharomyces cerevisiae strain for rapid anaerobic xylose fermentation

    Microsoft Academic Search

    Marko Kuyper; Miranda M. P. Hartog; Maurice J. Toirkens; Marinka J. H. Almering; Aaron A. Winkler; Johannes P. van Dijken; Jack T. Pronk

    2005-01-01

    After an extensive selection procedure, Saccharomyces cerevisiae strains that express the xylose isomerase gene from the fungus Piromyces sp. E2 can grow anaerobically on xylose with a ?max of 0.03 h?1. In order to investigate whether reactions downstream of the isomerase control the rate of xylose consumption, we overexpressed structural genes for all enzymes involved in the conversion of xylulose

  4. ANAEROBIC BIODEGRADATION OF VEGETABLE OIL AND ITS METABOLIC INTERMEDIATES IN OIL-ENRICHED FRESHWATER SEDIMENTS

    EPA Science Inventory

    Anaerobic biodegradation of vegetable oil in freshwater sediments is strongly inhibited by high concentrations of oil, but the presence of ferric hydroxide relieves the inhibition. The effect of ferric hydroxide is not due to physical or chemical interactions with long-chain fatt...

  5. Energy flows, metabolism and translation.

    PubMed

    Pascal, Robert; Boiteau, Laurent

    2011-10-27

    Thermodynamics provides an essential approach to understanding how living organisms survive in an organized state despite the second law. Exchanges with the environment constantly produce large amounts of entropy compensating for their own organized state. In addition to this constraint on self-organization, the free energy delivered to the system, in terms of potential, is essential to understand how a complex chemistry based on carbon has emerged. Accordingly, the amount of free energy brought about through discrete events must reach the strength needed to induce chemical changes in which covalent bonds are reorganized. The consequence of this constraint was scrutinized in relation to both the development of a carbon metabolism and that of translation. Amino acyl adenylates involved as aminoacylation intermediates of the latter process reach one of the higher free energy levels found in biochemistry, which may be informative on the range in which energy was exchanged in essential early biochemical processes. The consistency of this range with the amount of energy needed to weaken covalent bonds involving carbon may not be accidental but the consequence of the above mentioned thermodynamic constraints. This could be useful in building scenarios for the emergence and early development of translation. PMID:21930587

  6. Energy flows, metabolism and translation

    PubMed Central

    Pascal, Robert; Boiteau, Laurent

    2011-01-01

    Thermodynamics provides an essential approach to understanding how living organisms survive in an organized state despite the second law. Exchanges with the environment constantly produce large amounts of entropy compensating for their own organized state. In addition to this constraint on self-organization, the free energy delivered to the system, in terms of potential, is essential to understand how a complex chemistry based on carbon has emerged. Accordingly, the amount of free energy brought about through discrete events must reach the strength needed to induce chemical changes in which covalent bonds are reorganized. The consequence of this constraint was scrutinized in relation to both the development of a carbon metabolism and that of translation. Amino acyl adenylates involved as aminoacylation intermediates of the latter process reach one of the higher free energy levels found in biochemistry, which may be informative on the range in which energy was exchanged in essential early biochemical processes. The consistency of this range with the amount of energy needed to weaken covalent bonds involving carbon may not be accidental but the consequence of the abovementioned thermodynamic constraints. This could be useful in building scenarios for the emergence and early development of translation. PMID:21930587

  7. Geochemical constraints on sources of metabolic energy for chemolithoautotrophy in ultramafic-hosted deep-sea hydrothermal systems.

    PubMed

    McCollom, Thomas M

    2007-12-01

    Numerical models are employed to investigate sources of chemical energy for autotrophic microbial metabolism that develop during mixing of oxidized seawater with strongly reduced fluids discharged from ultramafic-hosted hydrothermal systems on the seafloor. Hydrothermal fluids in these systems are highly enriched in H(2) and CH(4) as a result of alteration of ultramafic rocks (serpentinization) in the subsurface. Based on the availability of chemical energy sources, inferences are made about the likely metabolic diversity, relative abundance, and spatial distribution of microorganisms within ultramafic-hosted systems. Metabolic reactions involving H(2) and CH(4), particularly hydrogen oxidation, methanotrophy, sulfate reduction, and methanogenesis, represent the predominant sources of chemical energy during fluid mixing. Owing to chemical gradients that develop from fluid mixing, aerobic metabolisms are likely to predominate in low-temperature environments (<20-30 degrees C), while anaerobes will dominate higher-temperature environments. Overall, aerobic metabolic reactions can supply up to approximately 7 kJ of energy per kilogram of hydrothermal fluid, while anaerobic metabolic reactions can supply about 1 kJ, which is sufficient to support a maximum of approximately 120 mg (dry weight) of primary biomass production by aerobic organisms and approximately 20-30 mg biomass by anaerobes. The results indicate that ultramafic-hosted systems are capable of supplying about twice as much chemical energy as analogous deep-sea hydrothermal systems hosted in basaltic rocks. PMID:18163871

  8. Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea

    DOE PAGESBeta

    Rother, Michael; Krzycki, Joseph A.

    2010-01-01

    Methanogenic archaea are a group of strictly anaerobic microorganisms characterized by their strict dependence on the process of methanogenesis for energy conservation. Among the archaea, they are also the only known group synthesizing proteins containing selenocysteine or pyrrolysine. All but one of the known archaeal pyrrolysine-containing and all but two of the confirmed archaeal selenocysteine-containing protein are involved in methanogenesis. Synthesis of these proteins proceeds through suppression of translational stop codons but otherwise the two systems are fundamentally different. This paper highlights these differences and summarizes the recent developments in selenocysteine- and pyrrolysine-related research on archaea and aims to putmore »this knowledge into the context of their unique energy metabolism.« less

  9. Probing the redox metabolism in the strictly anaerobic, extremely thermophilic, hydrogen-producing Caldicellulosiruptor saccharolyticus using amperometry.

    PubMed

    Kostesha, Natalie; Willquist, Karin; Emneus, Jenny; van Niel, Ed W J

    2011-01-01

    Changes in the redox metabolism in the anaerobic, extremely thermophilic, hydrogen-forming bacterium Caldicellulosiruptor saccharolyticus were probed for the first time in vivo using mediated amperometry with ferricyanide as a thermotolerant external mediator. Clear differences in the intracellular electron flow were observed when cells were supplied with different carbon sources. A higher electrochemical response was detected when cells were supplied with xylose than with sucrose or glucose. Moreover, using the mediated electrochemical method, it was possible to detect differences in the electron flow between cells harvested in the exponential and stationary growth phases. The electron flow of C. saccharolyticus was dependent on the NADH- and reduced ferredoxin generation flux and the competitive behavior of cytosolic and membrane-associated oxidoreductases. Sodium oxamate was used to inhibit the NADH-dependent lactate dehydrogenase, upon which more NADH was directed to membrane-associated enzymes for ferricyanide reduction, leading to a higher electrochemical signal. The method is noninvasive and the results presented here demonstrate that this method can be used to accurately detect changes in the intracellular electron flow and to probe redox enzyme properties of a strictly anaerobic thermophile in vivo. PMID:21132340

  10. Carboxylation as an Initial Reaction in the Anaerobic Metabolism of Naphthalene and Phenanthrene by Sulfidogenic Consortia

    Microsoft Academic Search

    XIAOMING ZHANG; L. Y. YOUNG

    1997-01-01

    The anaerobic biodegradation of naphthalene (NAP) and phenanthrene (PHE) was investigated by using sediment collected from the Arthur Kill in New York\\/New Jersey harbor. The initial cultures were composed of 10% sediment and 90% mineral medium containing 20 mM sulfate. Complete loss of NAP and PHE (150 to 200 mM) was observed after 150 days of incubation. Upon refeeding, NAP

  11. Characterization of the periplasmic redox network that sustains the versatile anaerobic metabolism of Shewanella oneidensis MR-1

    PubMed Central

    Alves, Mónica N.; Neto, Sónia E.; Alves, Alexandra S.; Fonseca, Bruno M.; Carrêlo, Afonso; Pacheco, Isabel; Paquete, Catarina M.; Soares, Cláudio M.; Louro, Ricardo O.

    2015-01-01

    The versatile anaerobic metabolism of the Gram-negative bacterium Shewanella oneidensis MR-1 (SOMR-1) relies on a multitude of redox proteins found in its periplasm. Most are multiheme cytochromes that carry electrons to terminal reductases of insoluble electron acceptors located at the cell surface, or bona fide terminal reductases of soluble electron acceptors. In this study, the interaction network of several multiheme cytochromes was explored by a combination of NMR spectroscopy, activity assays followed by UV-visible spectroscopy and comparison of surface electrostatic potentials. From these data the small tetraheme cytochrome (STC) emerges as the main periplasmic redox shuttle in SOMR-1. It accepts electrons from CymA and distributes them to a number of terminal oxidoreductases involved in the respiration of various compounds. STC is also involved in the electron transfer pathway to reduce nitrite by interaction with the octaheme tetrathionate reductase (OTR), but not with cytochrome c nitrite reductase (ccNiR). In the main pathway leading the metal respiration STC pairs with flavocytochrome c (FccA), the other major periplasmic cytochrome, which provides redundancy in this important pathway. The data reveals that the two proteins compete for the binding site at the surface of MtrA, the decaheme cytochrome inserted on the periplasmic side of the MtrCAB–OmcA outer-membrane complex. However, this is not observed for the MtrA homologues. Indeed, neither STC nor FccA interact with MtrD, the best replacement for MtrA, and only STC is able to interact with the decaheme cytochrome DmsE of the outer-membrane complex DmsEFABGH. Overall, these results shown that STC plays a central role in the anaerobic respiratory metabolism of SOMR-1. Nonetheless, the trans-periplasmic electron transfer chain is functionally resilient as a consequence of redundancies that arise from the presence of alternative pathways that bypass/compete with STC.

  12. Investigation of possible alternate end products of anaerobic metabolism in the Gulf toadfish, Opsanus beta 

    E-print Network

    Trant, John Miller

    1981-01-01

    ). Hypoxic f1sh heart (x = 7. 2 uM lactate/g, 24 Fig. 4. Concentration means +1 SEN of lactate within liver tissue exposed to various treatments sampled at discrete time intervals. Hypoxia accl1mated fish liver ( f ); in vitro anaerobic treatment ( ? e... biochemicals at various times within in vivo muscle tissue of anoxic fish injected wit~hC 4 glucose. . . . . . . . . . Means +1 SEM of total recovered activity and activity associated with six biochemicals at various times within in vivo liver tissue...

  13. Cerebral energy metabolism in isovaleric acidaemia.

    PubMed Central

    Lorek, A. K.; Penrice, J. M.; Cady, E. B.; Leonard, J. V.; Wyatt, J. S.; Iles, R. A.; Burns, S. P.; Reynolds, E. O.

    1996-01-01

    A newborn infant with an acute metabolic encephalopathy caused by isovaleric acidaemia had severe impairment of cerebral energy metabolism. This was detected by phosphorus and proton magnetic resonance spectroscopy. After treatment she made excellent clinical recovery, her spectroscopic abnormalities resolved, and she was neurologically normal at the age of 1 year. PMID:8777688

  14. Anaerobic-aerobic sequencing bioreactors improve energy efficiency for treatment of personal care product industry wastes.

    PubMed

    Ahammad, S Z; Bereslawski, J L; Dolfing, J; Mota, C; Graham, D W

    2013-07-01

    Personal care product (PCP) industry liquid wastes contain shampoo residues, which are usually treated by aerobic activated sludge (AS). Unfortunately, AS is expensive for PCP wastes because of high aeration and energy demands, whereas potentially energy-positive anaerobic designs cannot meet effluent targets. Therefore, combined anaerobic-aerobic systems may be the best solution. Seven treatment systems were assessed in terms of energy and treatment performance for shampoo wastes, including one aerobic, three anaerobic (HUASB, AHR and AnCSTR) and three anaerobic-aerobic reactor designs. COD removals were highest in the HUASB-aerobic (87.9 ± 0.4%) and AHR-aerobic (86.8±0.5%) systems, which used 69.2% and 62.5% less energy than aerobic AS. However, actual methane production rates were low relative to theoretical in the UASB and AHR units (?10% methane/COD removed) compared with the AnCSTR unit (?70%). Anaerobic-aerobic sequence reactors show promise for treating shampoo wastes, but optimal designs depend upon whether methane production or COD removal is most important to operations. PMID:23639409

  15. Energy and nutrient recovery from anaerobic treatment of organic wastes

    NASA Astrophysics Data System (ADS)

    Henrich, Christian-Dominik

    The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an "Ammonia Recovery Process" (ARP) consisting of: (1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, (2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, (3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, (4) high-rate algal post-treatment and finally, (5) an optional anaerobic digestion process for algal and bacterial biomass, and/or supplemental waste fermentation providing the potential for additional nutrient and energy recovery. In addition, the value provided by the waste treatment function of the overall processes, each of the sub-processes would provide valuable co-products offering potential GHG credit through direct fossil-fuel replacement, or replacement of products requiring fossil fuels. These valuable co-products include, (1) ammonium sulfate fertilizer, (2) bacterial biomass, (3) algal biomass providing, high-protein feeds and oils for biodiesel production and, (4) methane bio-fuels. Laboratory and pilot reactors were constructed and operated, providing data supporting the quantification and modeling of the ARP. Growth parameters, and stoichiometric coefficients were determined, allowing for design of the leachate activated sludge treatment sub-component. Laboratory and pilot algal reactors were constructed and operated, and provided data that supported the determination of leachate organic/inorganic-nitrogen ratio, and loading rates, allowing optimum performance of high-rate algal post-treatment. A modular and expandable computer program was developed, which provided a systems model framework capable of predicting individual component and overall performance. The overall systems model software, ENRAT, predicted that a full-scale operation to treat 18,750 L leachate/day would need an Ammonia Recovery process consisting of 88,300 L of total gas transfer column volume, an activated sludge system of 74,417 L, and an algal post treatment raceway of 683 m2 (30 cm depth). The ARP would consume 262.5 L/day of 6N sulfuric acid and produce 16.12 kg-N/day ammonium sulfate. The activated sludge system and algal post treatment would produce 900 g-VS/day (or 44.6 L 2% sludge) and 6.83 kg-VS/day (or 341.6 L 2% sludge) of bacterial and algal biomass.

  16. Formate Dehydrogenase, an Enzyme of Anaerobic Metabolism, Is Induced by Iron Deficiency in Barley Roots1

    PubMed Central

    Suzuki, Kazuya; Itai, Reiko; Suzuki, Koichiro; Nakanishi, Hiromi; Nishizawa, Naoko-Kishi; Yoshimura, Etsuro; Mori, Satoshi

    1998-01-01

    To identify the proteins induced by Fe deficiency, we have compared the proteins of Fe-sufficient and Fe-deficient barley (Hordeum vulgare L.) roots by two-dimensional polyacrylamide gel electrophoresis. Peptide sequence analysis of induced proteins revealed that formate dehydrogenase (FDH), adenine phosphoribosyltransferase, and the Ids3 gene product (for Fe deficiency-specific) increased in Fe-deficient roots. FDH enzyme activity was detected in Fe-deficient roots but not in Fe-sufficient roots. A cDNA encoding FDH (Fdh) was cloned and sequenced. Fdh expression was induced by Fe deficiency. Fdh was also expressed under anaerobic stress and its expression was more rapid than that induced by Fe deficiency. Thus, the expression of Fdh observed in Fe-deficient barley roots appeared to be a secondary effect caused by oxygen deficiency in Fe-deficient plants. PMID:9489019

  17. A model-driven quantitative metabolomics analysis of aerobic and anaerobic metabolism in E. coli K-12 MG1655 that is biochemically and thermodynamically consistent.

    PubMed

    McCloskey, Douglas; Gangoiti, Jon A; King, Zachary A; Naviaux, Robert K; Barshop, Bruce A; Palsson, Bernhard O; Feist, Adam M

    2014-04-01

    The advent of model-enabled workflows in systems biology allows for the integration of experimental data types with genome-scale models to discover new features of biology. This work demonstrates such a workflow, aimed at establishing a metabolomics platform applied to study the differences in metabolomes between anaerobic and aerobic growth of Escherichia coli. Constraint-based modeling was utilized to deduce a target list of compounds for downstream method development. An analytical and experimental methodology was developed and tailored to the compound chemistry and growth conditions of interest. This included the construction of a rapid sampling apparatus for use with anaerobic cultures. The resulting genome-scale data sets for anaerobic and aerobic growth were validated by comparison to previous small-scale studies comparing growth of E. coli under the same conditions. The metabolomics data were then integrated with the E. coli genome-scale metabolic model (GEM) via a sensitivity analysis that utilized reaction thermodynamics to reconcile simulated growth rates and reaction directionalities. This analysis highlighted several optimal network usage inconsistencies, including the incorrect use of the beta-oxidation pathway for synthesis of fatty acids. This analysis also identified enzyme promiscuity for the pykA gene, that is critical for anaerobic growth, and which has not been previously incorporated into metabolic models of E coli. PMID:24249002

  18. Characterization of a corrinoid protein involved in the C1 metabolism of strict anaerobic bacterium Moorella thermoacetica.

    PubMed

    Das, Amaresh; Fu, Zheng-Qing; Tempel, Wolfram; Liu, Zhi-Jie; Chang, Jessie; Chen, Lirong; Lee, Doowon; Zhou, Weihong; Xu, Hao; Shaw, Neil; Rose, John P; Ljungdahl, Lars G; Wang, Bi-Cheng

    2007-04-01

    The strict anaerobic, thermophilic bacterium Moorella thermoacetica metabolizes C1 compounds for example CO(2)/H(2), CO, formate, and methanol into acetate via the Wood/Ljungdahl pathway. Some of the key steps in this pathway include the metabolism of the C1 compounds into the methyl group of methylenetetrahydrofolate (MTHF) and the transfer of the methyl group from MTHF to the methyl group of acetyl-CoA catalyzed by methyltransferase, corrinoid protein and CO dehydrogenase/acetyl CoA synthase. Recently, we reported the crystallization of a 25 kDa methanol-induced corrinoid protein from M. thermoacetica (Zhou et al., Acta Crystallogr F 2005; 61:537-540). In this study we analyzed the crystal structure of the 25 kDa protein and provide genetic and biochemical evidences supporting its role in the methanol metabolism of M. thermoacetia. The 25 kDa protein was encoded by orf1948 of contig 303 in the M. thermoacetica genome. It resembles similarity to MtaC the corrinoid protein of the methanol:CoM methyltransferase system of methane producing archaea. The latter enzyme system also contains two additional enzymes MtaA and MtaB. Homologs of MtaA and MtaB were found to be encoded by orf2632 of contig 303 and orf1949 of contig 309, respectively, in the M. thermoacetica genome. The orf1948 and orf1949 were co-transcribed from a single polycistronic operon. Metal analysis and spectroscopic data confirmed the presence of cobalt and the corrinoid in the purified 25 kDa protein. High resolution X-ray crystal structure of the purified 25 kDa protein revealed corrinoid as methylcobalamin with the imidazole of histidine as the alpha-axial ligand replacing benziimidazole, suggesting base-off configuration for the corrinoid. Methanol significantly activated the expression of the 25 kDa protein. Cyanide and nitrate inhibited methanol metabolism and suppressed the level of the 25 kDa protein. The results suggest a role of the 25 kDa protein in the methanol metabolism of M. thermoacetica. PMID:17211893

  19. Anaerobic central metabolic pathways in Shewanella oneidensis MR-1interpreted in the light of isotopic metabolite labeling, enzymeactivities and genome annotation

    SciTech Connect

    Tang, Yinjie J.; Meadows, Adam L.; Kirby, James; Keasling, Jay D.

    2006-06-27

    It has been proposed that during growth under anaerobic oroxygen-limited conditions Shewanella oneidensis MR-1 uses theserine-isocitrate lyase pathway common to many methylotrophic anaerobes,in which formaldehyde produced from pyruvate is condensed with glycine toform serine. The serine is then transformed through hydroxypyruvate andglycerate to enter central metabolism at phosphoglycerate. To examine itsuse of the serine-isocitrate lyase pathway under anaerobic conditions, wegrew S. oneidensis MR-1 on [1-13C]lactate as the sole carbon source witheither trimethylamine N-oxide (TMAO) or fumarate as an electron acceptor.Analysis of cellular metabolites indicates that a large percentage(>75 percent) of lactate was partially oxidized to either acetate orpyruvate. The 13C isotope distributions in amino acids and other keymetabolites indicate that, under anaerobic conditions, a complete serinepathway is not present, and lactate is oxidized via a highly reversibleserine degradation pathway. The labeling data also suggest significantactivity in the anaplerotic (malic enzyme and phosphoenolpyruvatecarboxylase) and glyoxylate shunt (isocitrate lyase and malate synthase)reactions. Although the tricarboxylic acid (TCA) cycle is often observedto be incomplete in many other anaerobes (absence of 2-oxoglutaratedehydrogenase activity), isotopic labeling supports the existence of acomplete TCA cycle in S. oneidensis MR-1 under TMAO reductioncondition.

  20. Methane production through anaerobic digestion of various energy crops grown in sustainable crop rotations

    Microsoft Academic Search

    Thomas Amon; Barbara Amon; Vitaliy Kryvoruchko; Andrea Machmüller; Katharina Hopfner-Sixt; Vitomir Bodiroza; Regina Hrbek; Jürgen Friedel; Erich Pötsch; Helmut Wagentristl; Matthias Schreiner; Werner Zollitsch

    2007-01-01

    Biogas production is of major importance for the sustainable use of agrarian biomass as renewable energy source. Economic biogas production depends on high biogas yields. The project aimed at optimising anaerobic digestion of energy crops. The following aspects were investigated: suitability of different crop species and varieties, optimum time of harvesting, specific methane yield and methane yield per hectare. The

  1. INSECT FAT BODY: ENERGY, METABOLISM, AND REGULATION

    PubMed Central

    Arrese, Estela L.; Soulages, Jose L.

    2010-01-01

    The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects. PMID:19725772

  2. Life-Cycle Analysis of Energy and Greenhouse Gas Emissions from Anaerobic Biodegradation of Municipal Solid Waste

    Microsoft Academic Search

    Thomas D. DiStefano

    2009-01-01

    Energy requirements and greenhouse gas GHG emissions for current landfilling of municipal solid waste MSW was compared to potential biodegradation of MSW in anaerobic digesters AD throughout the United States. A hybrid life-cycle analysis was completed to assess the potential for anaerobic biodegradation of MSW to methane, a valuable energy source. Conversion of MSW to methane in AD would generate

  3. Potential for energy generation from anaerobic digestion of food waste in Australia.

    PubMed

    Lou, Xian Fang; Nair, Jaya; Ho, Goen

    2013-03-01

    Published national and state reports have revealed that Australia deposits an average of 16 million Mg of solid waste into landfills yearly, of which approximately 12.6% is comprised of food. Being highly biodegradable and possessing high energy content, anaerobic digestion offers an attractive treatment option alternative to landfilling. The present study attempted to identify the theoretical maximum benefit of food waste digestion in Australia with regard to energy recovery and waste diversion from landfills. The study also assessed the scope for anaerobic process to utilize waste for energy projects through various case study scenarios. Results indicated anaerobic digestion of total food waste generated across multiple sites in Australia could generate 558 453 dam(3) of methane which translated to 20.3 PJ of heating potential or 1915 GWe in electricity generation annually. This would contribute to 3.5% of total current energy supply from renewable sources. Energy contribution from anaerobic digestion of food waste to the total energy requirement in Australia remains low, partially due to the high energy consumption of the country. However its appropriateness in low density regions, which are prevalent in Australia, may allow digesters to have a niche application in the country. PMID:23381970

  4. Anaerobic arginine metabolism of Mycobacterium tuberculosis is mediated by arginine deiminase (arcA), but is not essential for chronic persistence in an aerogenic mouse model of infection.

    PubMed

    Sürken, Michael; Keller, Christine; Röhker, Claudia; Ehlers, Stefan; Bange, Franz-Christoph

    2008-10-01

    In many pathogens, degradation of arginine via the arginine deiminase pathway supports anaerobic metabolism. Here we show by deletion of Rv1001 (arcA) in Mycobacterium tuberculosis that this gene functions as an arginine deiminase. Arginine metabolism in the presence of oxygen was not affected by the mutation, indicating a separate pathway for arginine degradation under aerobic conditions. Following aerosol infection in mice, the DeltaarcA mutant and wild-type strain of M. tuberculosis multiplied and persisted in infected organs in a similar fashion. PMID:18032107

  5. STUDIES ON THE CARBOHYDRATE METABOLISM OF A GRAM-NEGATIVE ANAEROBE (BACTEROIDES SYMBIOSUS) USED IN THE CULTURE OF ENTAMOEBA HISTOLYTICA1

    PubMed Central

    Bragg, P. D.; Reeves, Richard E.

    1962-01-01

    Bragg, P. D. (Louisiana State University, New Orleans) and R. E. Reeves. Studies on the carbohydrate metabolism of a gram-negative anaerobe (Bacteroides symbiosus) used in the culture of Entamoeba histolytica. J. Bacteriol. 83:76–84. 1962—Resting cells of Bacteroides symbiosus have been shown to utilize glucose and several other monosaccharides. The fermentation of the sugars is mediated by demonstrable kinases except in the case of mannitol. The main end products of metabolism of glucose are CO2, H2, ethanol, and acetic, butyric, succinic, and lactic acids. Changes in the thiol used in the growth media produce different enzyme complements in the cells. Thus, cells grown with cysteine as the thiol are unable to metabolize glucosamine, whereas those grown with thiomalate rapidly degrade the amino sugar. The results of the enzyme assay and the results from experiments with C14-labelled glucose suggest that glucose is metabolized by resting cells mainly by the Embden-Myerhof pathway. PMID:13872395

  6. Activation of anaerobic metabolism in Biomphalaria glabrata (Mollusca: Gastropoda) experimentally infected by Angiostrongylus cantonensis (Nematoda, Metastrongylidae) by high-performance liquid chromatography.

    PubMed

    Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Castro, Rosane N; Sant'Ana, Luiza D'Oliveira; Santos-Amaral, Luciana; de Oliveira, Ana Paula Martins; Garcia, Juberlan; Thiengo, Silvana Carvalho; Pinheiro, Jairo; Maldonado, Arnaldo

    2014-02-01

    The activity of lactate dehydrogenase and the concentrations of glucose in the hemolymph and of glycogen in the digestive gland and cephalopedal mass of Biomphalaria glabrata experimentally infected with Angiostrongylus cantonensis were evaluated. Additionally, high performance liquid chromatography (HPLC) was used to determine the hemolymph concentrations of some carboxylic acids (oxalic, piruvic, lactic and succinic). After one, two and three weeks of infection, the snails were dissected to collect the hemolymph and separate the tissues. A significant reduction of the levels of glucose in the hemolymph was observed as of the first week of infection in relation to the control group. The lactate dehydrogenase activity of the infected group was significantly higher than the average of the control group. This increase was accompanied by a reduction of the levels of piruvic acid and an increase in the levels of lactic acid in the hemolymph of the parasited snails, confirming the acceleration of the anaerobic metabolism, necessary for the host to obtain energy and maintain its redox balance. In parallel, there was a decrease in the glycogen content of the storage tissues, with that reduction being significantly greater in the cephalopedal mass than the digestive gland, demonstrating that in this interaction system, the mobilization of glycogen was not sufficient to maintain and reestablish the normal glycemia of the infected snails. PMID:24042059

  7. Organ specific analysis of the anaerobic primary metabolism in rice and wheat seedlings II: light exposure reduces needs for fermentation and extends survival during anaerobiosis.

    PubMed

    Mustroph, Angelika; Boamfa, Elena I; Laarhoven, Lucas J J; Harren, Frans J M; Pörs, Yvonne; Grimm, Bernhard

    2006-12-01

    Low oxygen stress in plants can occur during flooding and compromise the availability and utilization of carbohydrates in root and shoot tissues. Low-oxygen-tolerant rice and -sensitive wheat plants were analyzed under anaerobiosis in light to evaluate main factors of the primary metabolism that affect sensitivity against oxygen deprivation: activity of glycolysis and the rate of photosynthesis. Relatively stable ATP contents (93 and 58% of aerated control levels after 24 h anaerobiosis) in illuminated shoot tissues account for enhanced tolerance of rice and wheat seedlings to anaerobiosis upon light exposure in comparison to anoxia in darkness. Although the photosynthetic process was inhibited during low oxygen stress, which was partly due to CO(2) deficiency, more light-exposed than dark-incubated seedlings survived. Illuminated plants could tolerate a 70% lower anaerobic ethanol production in shoots in comparison to darkness, although still an 18-times higher ethanol production rate was determined in rice than in wheat leaves. In conclusion, light-exposed plants grown under anaerobiosis may recycle low amounts of generated oxygen between photosynthesis and dissimilation and generate additional energy not only from substrate phosphorylation during glycolysis but also from other sources like cyclic electron transport. PMID:16802177

  8. Mitochondrial Energy Metabolism and Thyroid Cancers

    PubMed Central

    Lee, Junguee; Chang, Joon Young; Kang, Yea Eun; Yi, Shinae; Lee, Min Hee; Joung, Kyong Hye; Kim, Kun Soon

    2015-01-01

    Primary thyroid cancers including papillary, follicular, poorly differentiated, and anaplastic carcinomas show substantial differences in biological and clinical behaviors. Even in the same pathological type, there is wide variability in the clinical course of disease progression. The molecular carcinogenesis of thyroid cancer has advanced tremendously in the last decade. However, specific inhibition of oncogenic pathways did not provide a significant survival benefit in advanced progressive thyroid cancer that is resistant to radioactive iodine therapy. Accumulating evidence clearly shows that cellular energy metabolism, which is controlled by oncogenes and other tumor-related factors, is a critical factor determining the clinical phenotypes of cancer. However, the role and nature of energy metabolism in thyroid cancer remain unclear. In this article, we discuss the role of cellular energy metabolism, particularly mitochondrial energy metabolism, in thyroid cancer. Determining the molecular nature of metabolic remodeling in thyroid cancer may provide new biomarkers and therapeutic targets that may be useful in the management of refractory thyroid cancers. PMID:26194071

  9. Principles of Human Energy Metabolism

    Microsoft Academic Search

    Jose Galgani; Eric Ravussin

    \\u000a Energy is defined as the ability of a system to perform work. Energy is present in many forms, such as luminous energy coming\\u000a from sun or kinetic energy obtained from wind and water. Humans obtain their energy from foods which is stored in the CH bonds\\u000a of carbohydrates, lipids, proteins, and alcohol. To obtain the energy to live, grow, and

  10. Acute effect of erythromycin on metabolic transformations of volatile fatty acid mixture under anaerobic conditions.

    PubMed

    Cetecioglu, Z; Ince, B; Ince, O; Orhon, D

    2015-04-01

    The study explored the acute inhibitory impact of erythromycin on the methanogenic activity of acclimated biomass fed with a volatile fatty acid mixture and acetate alone. Parallel batch reactors were operated for six days, with increasing erythromycin dosing in the range of 1-1000 mg L(-1). Substrate removal was monitored by means of soluble COD and volatile fatty acid (VFA) measurements together with parallel observations on biogas and methane generation. The inhibitory impact was variable with the initial erythromycin dose: At lower doses, the VFA mixture was completely removed but partially utilized, leading to reduced biogas and methane generation, suggesting the analogy of uncompetitive inhibition. At higher doses, propionate utilization was totally impaired and butyrate removal was reduced, but acetate was still fully removed. Remaining VFAs were partly converted to new VFA compound through isomerization and polymerization reactions. High erythromycin doses induced total inactivation of microbial metabolism with negligible methane generation. PMID:25542637

  11. Contribution of anaerobic protozoa and methanogens to hindgut metabolic activities of the American cockroach, Periplaneta americana.

    PubMed Central

    Gijzen, H J; Barugahare, M

    1992-01-01

    The ciliate Nyctotherus ovalis occurs in high numbers in the hindgut of the American cockroach (Periplaneta americana) and harbors methanogenic bacteria as endosymbionts. The contribution of these hindgut microorganisms to metabolic and developmental processes of P. americana was studied by comparing cultures of cockroaches in which the composition of the hindgut microbial population was altered in various ways. Rearing the insects protozoan free resulted in increased insect generation time, decreased adult body weight, and absence of methane production. After feeding of protozoan-free adult cockroaches with a hindgut suspension containing N. ovalis and methanogens, methane increased to normal values and insect body weight was restored during the development of the second generation of insects. Feeding the protozoan-free cockroaches a hindgut suspension which was made free of N. ovalis resulted in an increase in methane production to only about 20% of the normal methane production level. This suggests that the methanogenic endosymbionts of N. ovalis are the major source of methane production in the hindgut. Inhibition of methanogens by addition of bromoethanesulfonic acid to the drinking water of a normal cockroach culture resulted in a reduction of methane production to about 2% of the normal level. No effects on insect body weight or the number of N. ovalis organisms were observed, but the fermentation pattern in the hindgut was shifted towards a relative increase in propionate levels. Similar results were obtained for in vitro cultures of hindgut microorganisms treated with bromoethanesulfonic acid. The results suggest a major role for hindgut protozoa in cockroach metabolic activities, especially during the insect growth period. The relatively large amounts of methane produced by cockroaches and by other methane-producing xylophagous insects suggest a major contribution by insects to global methane production. PMID:1514803

  12. Contribution of anaerobic protozoa and methanogens to hindgut metabolic activities of the American cockroach, Periplaneta americana.

    PubMed

    Gijzen, H J; Barugahare, M

    1992-08-01

    The ciliate Nyctotherus ovalis occurs in high numbers in the hindgut of the American cockroach (Periplaneta americana) and harbors methanogenic bacteria as endosymbionts. The contribution of these hindgut microorganisms to metabolic and developmental processes of P. americana was studied by comparing cultures of cockroaches in which the composition of the hindgut microbial population was altered in various ways. Rearing the insects protozoan free resulted in increased insect generation time, decreased adult body weight, and absence of methane production. After feeding of protozoan-free adult cockroaches with a hindgut suspension containing N. ovalis and methanogens, methane increased to normal values and insect body weight was restored during the development of the second generation of insects. Feeding the protozoan-free cockroaches a hindgut suspension which was made free of N. ovalis resulted in an increase in methane production to only about 20% of the normal methane production level. This suggests that the methanogenic endosymbionts of N. ovalis are the major source of methane production in the hindgut. Inhibition of methanogens by addition of bromoethanesulfonic acid to the drinking water of a normal cockroach culture resulted in a reduction of methane production to about 2% of the normal level. No effects on insect body weight or the number of N. ovalis organisms were observed, but the fermentation pattern in the hindgut was shifted towards a relative increase in propionate levels. Similar results were obtained for in vitro cultures of hindgut microorganisms treated with bromoethanesulfonic acid. The results suggest a major role for hindgut protozoa in cockroach metabolic activities, especially during the insect growth period. The relatively large amounts of methane produced by cockroaches and by other methane-producing xylophagous insects suggest a major contribution by insects to global methane production. PMID:1514803

  13. High ethanol titers from cellulose by using metabolically engineered thermophilic, anaerobic microbes.

    PubMed

    Argyros, D Aaron; Tripathi, Shital A; Barrett, Trisha F; Rogers, Stephen R; Feinberg, Lawrence F; Olson, Daniel G; Foden, Justine M; Miller, Bethany B; Lynd, Lee R; Hogsett, David A; Caiazza, Nicky C

    2011-12-01

    This work describes novel genetic tools for use in Clostridium thermocellum that allow creation of unmarked mutations while using a replicating plasmid. The strategy employed counter-selections developed from the native C. thermocellum hpt gene and the Thermoanaerobacterium saccharolyticum tdk gene and was used to delete the genes for both lactate dehydrogenase (Ldh) and phosphotransacetylase (Pta). The ?ldh ?pta mutant was evolved for 2,000 h, resulting in a stable strain with 40:1 ethanol selectivity and a 4.2-fold increase in ethanol yield over the wild-type strain. Ethanol production from cellulose was investigated with an engineered coculture of organic acid-deficient engineered strains of both C. thermocellum and T. saccharolyticum. Fermentation of 92 g/liter Avicel by this coculture resulted in 38 g/liter ethanol, with acetic and lactic acids below detection limits, in 146 h. These results demonstrate that ethanol production by thermophilic, cellulolytic microbes is amenable to substantial improvement by metabolic engineering. PMID:21965408

  14. Energy metabolism plasticity enables stemness programs.

    PubMed

    Folmes, Clifford D L; Nelson, Timothy J; Dzeja, Petras P; Terzic, Andre

    2012-04-01

    Engineering pluripotency through nuclear reprogramming and directing stem cells into defined lineages underscores cell fate plasticity. Acquisition of and departure from stemness are governed by genetic and epigenetic controllers, with modulation of energy metabolism and associated signaling increasingly implicated in cell identity determination. Transition from oxidative metabolism, typical of somatic tissues, into glycolysis is a prerequisite to fuel-proficient reprogramming, directing a differentiated cytotype back to the pluripotent state. The glycolytic metabotype supports the anabolic and catabolic requirements of pluripotent cell homeostasis. Conversely, redirection of pluripotency into defined lineages requires mitochondrial biogenesis and maturation of efficient oxidative energy generation and distribution networks to match demands. The vital function of bioenergetics in regulating stemness and lineage specification implicates a broader role for metabolic reprogramming in cell fate decisions and determinations of tissue regenerative potential. PMID:22548573

  15. Energy metabolism of Bdellovibrio bacteriovorus

    Microsoft Academic Search

    D. Gadkari; H. Stolp

    1975-01-01

    Bdellovibrio bacteriovorus, strain Bd. 109 Sa, generates ATP mainly by oxidative phosphorylation during electron transport. During exponential growth the ATP pool is constant (9 nmoles\\/100 µg N) indicating that energy-producing and energy-consuming reactions are well balanced. The ratio of substrate respiration\\/endogenous respiration is approx. 2.5\\/1. Energy charge is constant both in endogenous and substrate respiration at values of 0.62 to

  16. Biogas energy production from tropical biomass wastes by anaerobic digestion.

    PubMed

    Ge, Xumeng; Matsumoto, Tracie; Keith, Lisa; Li, Yebo

    2014-10-01

    Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass and food wastes, such as taro, papaya, and sweet potato, are limited. In this study, these tropical biomass wastes were evaluated for biogas production by liquid AD (L-AD) and/or solid-state AD (SS-AD), depending on feedstock characteristics. When albizia leaves and chips were used as feedstocks, L-AD had greater methane yields (161 and 113 L kg(-1)VS, respectively) than SS-AD (156.8 and 59.6 L kg(-1)VS, respectively), while SS-AD achieved 5-fold higher volumetric methane productivity than L-AD. Mono-digestion and co-digestion of taro skin, taro flesh, papaya, and sweet potato achieved methane yields from 345 to 411 L kg(-1)VS, indicating the robustness of AD technology. PMID:25022835

  17. Mitochondrial Lactate Dehydrogenase Is Involved in Oxidative-Energy Metabolism in Human Astrocytoma Cells (CCF-STTG1)

    Microsoft Academic Search

    Joseph Lemire; Ryan J. Mailloux; Vasu D. Appanna; George Brooks

    2008-01-01

    Lactate has long been regarded as an end product of anaerobic energy production and its fate in cerebral metabolism has not been precisely delineated. In this report, we demonstrate, for the first time, the ability of a human astrocytic cell line (CCF-STTG1) to consume lactate and to generate ATP via oxidative phosphorylation. 13C-NMR and HPLC analyses aided in the identification

  18. Life cycle assessment of energy from waste via anaerobic digestion: a UK case study.

    PubMed

    Evangelisti, Sara; Lettieri, Paola; Borello, Domenico; Clift, Roland

    2014-01-01

    Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO2 and total SO2 saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded. PMID:24112851

  19. Establishment and metabolic analysis of a model microbial community for understanding trophic and electron accepting interactions of subsurface anaerobic environments

    PubMed Central

    2010-01-01

    Background Communities of microorganisms control the rates of key biogeochemical cycles, and are important for biotechnology, bioremediation, and industrial microbiological processes. For this reason, we constructed a model microbial community comprised of three species dependent on trophic interactions. The three species microbial community was comprised of Clostridium cellulolyticum, Desulfovibrio vulgaris Hildenborough, and Geobacter sulfurreducens and was grown under continuous culture conditions. Cellobiose served as the carbon and energy source for C. cellulolyticum, whereas D. vulgaris and G. sulfurreducens derived carbon and energy from the metabolic products of cellobiose fermentation and were provided with sulfate and fumarate respectively as electron acceptors. Results qPCR monitoring of the culture revealed C. cellulolyticum to be dominant as expected and confirmed the presence of D. vulgaris and G. sulfurreducens. Proposed metabolic modeling of carbon and electron flow of the three-species community indicated that the growth of C. cellulolyticum and D. vulgaris were electron donor limited whereas G. sulfurreducens was electron acceptor limited. Conclusions The results demonstrate that C. cellulolyticum, D. vulgaris, and G. sulfurreducens can be grown in coculture in a continuous culture system in which D. vulgaris and G. sulfurreducens are dependent upon the metabolic byproducts of C. cellulolyticum for nutrients. This represents a step towards developing a tractable model ecosystem comprised of members representing the functional groups of a trophic network. PMID:20497531

  20. Anaerobic fermentative system based scheme for green energy sustainable houses

    Microsoft Academic Search

    Chen-Yeon Chu; Shang-Yuan Chen; Chyi-How Lay; Jou-Hsien Wu; Ming-jen Cheng; Chiu-Yue Lin

    2011-01-01

    The green energy sustainable house based on bio-hydrogen and bio-methane energy technologies proposed in this study employs dark fermentation technology to complete a scheme for green energy sustainable house that includes energy production, storage, distribution control, load applications, recycling, waste treatment, and reuse. In order to resolve the problem of wastewater discharge from hydrogen production in green energy sustainable houses,

  1. Thyroid hormone signaling in energy homeostasis and energy metabolism

    PubMed Central

    McAninch, Elizabeth A.; Bianco, Antonio C.

    2014-01-01

    The thyroid hormone plays a significant role in diverse processes related to growth, development, differentiation, and metabolism. Thyroid hormone signaling modulates energy expenditure through both central and peripheral pathways. At the cellular level, the thyroid hormone exerts its effects after concerted mechanisms facilitate binding to the thyroid hormone receptor. In the hypothalamus, signals from a range of metabolic pathways, including appetite, temperature, afferent stimuli via the autonomic nervous system, availability of energy substrates, hormones, and other biologically active molecules, converge to maintain plasma thyroid hormone at the appropriate level to preserve energy homeostasis. At the tissue level, thyroid hormone actions on metabolism are controlled by transmembrane transporters, deiodinases, and thyroid hormone receptors. In the modern environment, humans are susceptible to an energy surplus, which has resulted in an obesity epidemic and thus understanding the contribution of the thyroid hormone to cellular and organism metabolism is increasingly relevant. PMID:24697152

  2. Muscle heat production and anaerobic energy turnover during repeated intense dynamic exercise in humans

    PubMed Central

    Krustrup, Peter; González-Alonso, José; Quistorff, Bjørn; Bangsbo, Jens

    2001-01-01

    The aim of the present study was to examine muscle heat production, oxygen uptake and anaerobic energy turnover throughout repeated intense exercise to test the hypotheses that (i) energy turnover is reduced when intense exercise is repeated and (ii) anaerobic energy production is diminished throughout repeated intense exercise. Five subjects performed three 3 min intense one-legged knee-extensor exercise bouts (EX1, EX2 and EX3) at a power output of 65 ± 5 W (mean ±s.e.m.), separated by 6 min rest periods. Muscle, femoral arterial and venous temperatures were measured continuously during exercise for the determination of muscle heat production. In addition, thigh blood flow was measured and femoral arterial and venous blood were sampled frequently during exercise for the determination of muscle oxygen uptake. Anaerobic energy turnover was estimated as the difference between total energy turnover and aerobic energy turnover. Prior to exercise, the temperature of the quadriceps muscle was passively elevated to 37.02 ± 0.12 °C and it increased 0.97 ± 0.08 °C during EX1, which was higher (P < 0.05) than during EX2 (0.79 ± 0.05 °C) and EX3 (0.77 ± 0.06 °C). In EX1 the rate of muscle heat accumulation was higher (P < 0.05) during the first 120 s compared to EX2 and EX3, whereas the rate of heat release to the blood was greater (P < 0.05) throughout EX2 and EX3 compared to EX1. The rate of heat production, determined as the sum of heat accumulation and release, was the same in EX1, EX2 and EX3, and it increased (P < 0.05) from 86 ± 8 during the first 15 s to 157 ± 7 J s?1 during the last 15 s of EX1. Oxygen extraction was higher during the first 60 s of EX2 and EX3 than in EX 1 and thigh oxygen uptake was elevated (P < 0.05) during the first 120 s of EX2 and throughout EX3 compared to EX1. The anaerobic energy production during the first 105 s of EX2 and 150 s of EX3 was lower (P < 0.05) than in EX1. The present study demonstrates that when intense exercise is repeated muscle heat production is not changed, but muscle aerobic energy turnover is elevated and anaerobic energy production is reduced during the first minutes of exercise. PMID:11691886

  3. Microbial Anaerobic Digestion (Bio-Digesters) as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    PubMed Central

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

    2013-01-01

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications. PMID:24048207

  4. Field-based and laboratory stable isotope probing surveys of the identities of both aerobic and anaerobic benzene-metabolizing microorganisms in freshwater sediment.

    PubMed

    Liou, J S-C; Derito, C M; Madsen, E L

    2008-08-01

    Laboratory incubations of coal-tar waste-contaminated sediment microbial communities under relatively controlled physiological conditions were used to interpret results of a field-based stable isotope probing (SIP) assay. Biodegradation activity of 13C-benzene was examined by GC/MS determination of net 13CO2 production and by GC headspace analysis of benzene loss. Key experimental variables were: the site of the assays (laboratory serum-bottle incubations and in situ field sediments), benzene concentration (10, 36 or 200 p.p.m. in laboratory assays), and physiological conditions (anaerobic with or without sulfate or nitrate additions versus aerobic headspace or the uncontrolled field). In anaerobic laboratory incubations of benzene at 10 p.p.m., greater than 60% of the substrate was eliminated within 15 days. During anaerobic incubations of 200 p.p.m. benzene (70 days), 0.9% benzene mineralization occurred. When benzene (36 p.p.m.) was added to sediment with air in the serum-bottle headspace, 14% of the initial 13C was mineralized to 13CO2 in 2.5 days. In the field experiment (178 microg 13C-benzene dosed to undisturbed sediments), net 13CO2 production reached 0.3% within 8.5 h. After isopycnic separation of 13C (heavy)-labelled DNA from the above biodegradation assays, sequencing of 13C-DNA clone libraries revealed a broad diversity of taxa involved in benzene metabolism and distinctive libraries for each biodegradation treatment. Perhaps most importantly, in the field SIP experiment the clone libraries produced were dominated by Pelomonas (betaproteobacteria) sequences similar to those found in the anaerobic 10 p.p.m. benzene laboratory experiment. These data indicate that the physiological conditions that prevail and govern in situ biodegradation of pollutants in the field may be interpreted by knowing the physiological preferences of potentially active populations. PMID:18430012

  5. Energy Metabolism and Human Dosimetry of Tritium

    SciTech Connect

    Galeriu, D.; Takeda, H.; Melintescu, A.; Trivedi, A

    2005-07-15

    In the frame of current revision of human dosimetry of {sup 14}C and tritium, undertaken by the International Commission of Radiological Protection, we propose a novel approach based on energy metabolism and a simple biokinetic model for the dynamics of dietary intake (organic {sup 14}C, tritiated water and Organically Bound Tritium-OBT). The model predicts increased doses for HTO and OBT comparing to ICRP recommendations, supporting recent findings.

  6. Metabolic adaptation in protein-energy malnutrition.

    PubMed

    Frenk, S

    1986-01-01

    The metabolic response to chronic undernutrition covers a wide spectrum that ranges from decreased growth velocity in mild cases to profound distortion of body silhouette and composition and functional derangements in advanced stages of the protein-energy malnutrition-infection complex. A wide gamut of molecular, enzymatic, and hormonal processes assure a temporary availability of endogenous nutrients and the maintenance of vital functions. PMID:3095409

  7. [Circadian clocks and energy metabolism in rodents].

    PubMed

    Challet, Etienne

    2014-01-01

    Circadian rhythmicity is an important component of physiological processes which provides them with a 24-hour temporal organization and adjustment to cyclical changes in the environment. Circadian rhythms are controlled by a network of endogenous clocks, comprising the main clock in the suprachiasmatic nuclei of the hypothalamus and many secondary clocks in the brain and peripheral tissues. All aspects of energy metabolism, from food intake to intracellular signaling pathways, are strongly influenced by circadian rhythmicity. In turn, meal timing is an efficient synchronizer (time-giver) to set the phase of the peripheral clocks, while the suprachiasmatic clock is synchronized by ambient light. In certain nutritional conditions (i.e., low- or high-calory diets), metabolic factors remaining to be identified modulate the functioning of the suprachiasmatic clock. Animal models of obesity and diabetes show circadian alterations. Conversely, when circadian rhythmicity is disturbed, either due to genetically defective circadian clocks, or to circadian desynchronization (chronic light exposure or repeated meals at odd times of the cycle), lipid and glucose metabolism is deregulated. The metabolic impact of circadian desynchronization justifies the development of preventive or therapeutic strategies that could rely, among others, on dietary interventions combining timed meals and specific composition. PMID:25840453

  8. A metabolic profiling approach to human disorders of energy metabolism

    E-print Network

    Shaham, Oded

    2009-01-01

    The integrated network of biochemical reactions known collectively as metabolism is essential for life, and dysfunction in parts of this network causes human disease - both rare, inherited disorders and common diseases ...

  9. Anaerobic co-digestion of the marine microalga Nannochloropsis salina with energy crops.

    PubMed

    Schwede, Sebastian; Kowalczyk, Alexandra; Gerber, Mandy; Span, Roland

    2013-11-01

    Anaerobic co-digestion of corn silage with the marine microalga Nannochloropsis salina was investigated under batch and semi-continuous conditions. Under batch conditions process stability and biogas yields significantly increased by microalgae addition. During semi-continuous long-term experiments anaerobic digestion was stable in corn silage mono- and co-digestion with the algal biomass for more than 200 days. At higher organic loading rates (4.7 kg volatile solids m(-3)d(-1)) inhibition and finally process failure occurred in corn silage mono-digestion, whereas acid and methane formation remained balanced in co-digestion. The positive influences in co-digestion can be attributed to an adjusted carbon to nitrogen ratio, enhanced alkalinity, essential trace elements and a balanced nutrient composition. The results suggest that N. salina biomass is a suitable feedstock for anaerobic co-digestion of energy crops, especially for regions with manure scarcity. Enhanced process stability may result in higher organic loading rates or lower digester volumes. PMID:24071442

  10. Mitochondrial uncoupling proteins and energy metabolism

    PubMed Central

    Busiello, Rosa A.; Savarese, Sabrina; Lombardi, Assunta

    2015-01-01

    Understanding the metabolic factors that contribute to energy metabolism (EM) is critical for the development of new treatments for obesity and related diseases. Mitochondrial oxidative phosphorylation is not perfectly coupled to ATP synthesis, and the process of proton-leak plays a crucial role. Proton-leak accounts for a significant part of the resting metabolic rate (RMR) and therefore enhancement of this process represents a potential target for obesity treatment. Since their discovery, uncoupling proteins have stimulated great interest due to their involvement in mitochondrial-inducible proton-leak. Despite the widely accepted uncoupling/thermogenic effect of uncoupling protein one (UCP1), which was the first in this family to be discovered, the reactions catalyzed by its homolog UCP3 and the physiological role remain under debate. This review provides an overview of the role played by UCP1 and UCP3 in mitochondrial uncoupling/functionality as well as EM and suggests that they are a potential therapeutic target for treating obesity and its related diseases such as type II diabetes mellitus. PMID:25713540

  11. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications.

    PubMed

    Buchheit, Martin; Laursen, Paul B

    2013-10-01

    High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ?95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p(·)VO(2max)] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6-8 km at v(·)VO(2max) per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load. PMID:23832851

  12. Anaerobic 2-ketogluconate metabolism of Klebsiella pneumoniae NCTC 418 grown in chemostat culture: involvement of the pentose phosphate pathway

    Microsoft Academic Search

    JWST A. SIMONS; JACKY L. SNOEP; SJOERD FEITZ; T. M. J. DE MATTOS; O. M. NEIJSSEL

    1992-01-01

    Under anaerobic 2-ketogluconate-limited growth conditions (D = 0.1 h-l), KlebsieZZupneumnhze NCTC 418 was found to convert this carbon source to biomass, acetate, formate, COz, ethanol and succinate. The observed fermentation pattern is in agreement with the simultaneous functioning of the pentose phosphate pathway and the Entner-Doudoroff pathway in 2-ketogluconate catabolism. When cultured at pH 8.0 apparent YATP values were lower

  13. The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism

    PubMed Central

    den Besten, Gijs; van Eunen, Karen; Groen, Albert K.; Venema, Koen; Reijngoud, Dirk-Jan; Bakker, Barbara M.

    2013-01-01

    Short-chain fatty acids (SCFAs), the end products of fermentation of dietary fibers by the anaerobic intestinal microbiota, have been shown to exert multiple beneficial effects on mammalian energy metabolism. The mechanisms underlying these effects are the subject of intensive research and encompass the complex interplay between diet, gut microbiota, and host energy metabolism. This review summarizes the role of SCFAs in host energy metabolism, starting from the production by the gut microbiota to the uptake by the host and ending with the effects on host metabolism. There are interesting leads on the underlying molecular mechanisms, but there are also many apparently contradictory results. A coherent understanding of the multilevel network in which SCFAs exert their effects is hampered by the lack of quantitative data on actual fluxes of SCFAs and metabolic processes regulated by SCFAs. In this review we address questions that, when answered, will bring us a great step forward in elucidating the role of SCFAs in mammalian energy metabolism. PMID:23821742

  14. CKM Gene G (Ncoi-) Allele Has a Positive Effect on Maximal Oxygen Uptake in Caucasian Women Practicing Sports Requiring Aerobic and Anaerobic Exercise Metabolism

    PubMed Central

    Gronek, Piotr; Holdys, Joanna; Kry?ciak, Jakub; Stanis?awski, Daniel

    2013-01-01

    The search for genes with a positive influence on physical fitness is a difficult process. Physical fitness is a trait determined by multiple genes, and its genetic basis is then modified by numerous environmental factors. The present study examines the effects of the polymorphism of creatine kinase (CKM) gene on VO2max – a physiological index of aerobic capacity of high heritability. The study sample consisted of 154 men and 85 women, who were students of the University School of Physical Education in Pozna? and athletes practicing various sports, including members of the Polish national team. The study revealed a positive effect of a rare G (NcoI?) allele of the CKM gene on maximal oxygen uptake in Caucasian women practicing sports requiring aerobic and anaerobic exercise metabolism. Also a tendency was noted in individuals with NcoI?/? (GG) and NcoI?/+ (GA) genotypes to reach higher VO2max levels. PMID:24511349

  15. Methane production through anaerobic digestion of various energy crops grown in sustainable crop rotations.

    PubMed

    Amon, Thomas; Amon, Barbara; Kryvoruchko, Vitaliy; Machmüller, Andrea; Hopfner-Sixt, Katharina; Bodiroza, Vitomir; Hrbek, Regina; Friedel, Jürgen; Pötsch, Erich; Wagentristl, Helmut; Schreiner, Matthias; Zollitsch, Werner

    2007-12-01

    Biogas production is of major importance for the sustainable use of agrarian biomass as renewable energy source. Economic biogas production depends on high biogas yields. The project aimed at optimising anaerobic digestion of energy crops. The following aspects were investigated: suitability of different crop species and varieties, optimum time of harvesting, specific methane yield and methane yield per hectare. The experiments covered 7 maize, 2 winter wheat, 2 triticale varieties, 1 winter rye, and 2 sunflower varieties and 6 variants with permanent grassland. In the course of the vegetation period, biomass yield and biomass composition were measured. Anaerobic digestion was carried out in eudiometer batch digesters. The highest methane yields of 7500-10200 m(N)(3)ha(-1) were achieved from maize varieties with FAO numbers (value for the maturity of the maize) of 300 to 600 harvested at "wax ripeness". Methane yields of cereals ranged from 3200 to 4500 m(N)(3)ha(-1). Cereals should be harvested at "grain in the milk stage" to "grain in the dough stage". With sunflowers, methane yields between 2600 and 4550 m(N)(3)ha(-1) were achieved. There were distinct differences between the investigated sunflower varieties. Alpine grassland can yield 2700-3500 m(N)(3)CH(4)ha(-1). The methane energy value model (MEVM) was developed for the different energy crops. It estimates the specific methane yield from the nutrient composition of the energy crops. Energy crops for biogas production need to be grown in sustainable crop rotations. The paper outlines possibilities for optimising methane yield from versatile crop rotations that integrate the production of food, feed, raw materials and energy. These integrated crop rotations are highly efficient and can provide up to 320 million t COE which is 96% of the total energy demand of the road traffic of the EU-25 (the 25 Member States of the European Union). PMID:16935493

  16. Hydrogenosomes: convergent adaptations of mitochondria to anaerobic environments.

    PubMed

    Hackstein, J H; Akhmanova, A; Voncken, F; van Hoek, A; van Alen, T; Boxma, B; Moon-van der Staay, S Y; van der Staay, G; Leunissen, J; Huynen, M; Rosenberg, J; Veenhuis, M

    2001-01-01

    Hydrogenosomes are membrane-bound organelles that compartmentalise the final steps of energy metabolism in a number of anaerobic eukaryotes. They produce hydrogen and ATP. Here we will review the data, which are relevant for the questions: how did the hydrogenosomes originate, and what was their ancestor? Notably, there is strong evidence that hydrogenosomes evolved several times as adaptations to anaerobic environments. Most likely, hydrogenosomes and mitochondria share a common ancestor, but an unequivocal proof for this hypothesis is difficult because hydrogenosomes lack an organelle genome - with one remarkable exception (Nyctotherus ovalis). In particular, the diversity of extant hydrogenosomes hampers a straightforward analysis of their origins. Nevertheless, it is conceivable to postulate that the common ancestor of mitochondria and hydrogenosomes was a facultative anaerobic organelle that participated in the early radiation of unicellular eukaryotes. Consequently, it is reasonable to assume that both, hydrogenosomes and mitochondria are evolutionary adaptations to anaerobic or aerobic environments, respectively. PMID:16351844

  17. Anaerobic phosphate release from activated sludge with enhanced biological phosphorus removal. A possible mechanism of intracellular pH control

    SciTech Connect

    Bond, P.L.; Keller, J.; Blackall, L.L. [Univ. of Queensland, Brisbane (Australia)] [Univ. of Queensland, Brisbane (Australia)

    1999-06-05

    The biochemical mechanisms of the wastewater treatment process known as enhanced biological phosphorus removal (EBPR) are presently described in a metabolic model. The authors investigated details of the EBPR model to determine the nature of the anaerobic phosphate release and how this may be metabolically associated with polyhydroxyalkanoate (PHA) formation. Iodoacetate, an inhibitor of glycolysis, was found to inhibit the anaerobic formation of PHA and phosphate release, supporting the pathways proposed in the EBPR metabolic model. In the metabolic model, it is proposed that polyphosphate degradation provides energy for the microorganisms in anaerobic regions of these treatment systems. Other investigations have shown that anaerobic phosphate release depends on the extracellular pH. The authors observed that when the intracellular pH of EBPR sludge was raised, substantial anaerobic phosphate release was caused without volatile fatty acid (VFA) uptake. Acidification of the sludge inhibited anaerobic phosphate release even in the presence of VFA. from these observations, the authors postulate that an additional possible role of anaerobic polyphosphate degradation in EBPR is for intracellular pH control. Intracellular pH control may be a metabolic feature of EBPR, not previously considered, that could have some use in the control and optimization of EBPR.

  18. Two-stage anaerobic digestion of energy crops: methane production, nitrogen mineralisation and heavy metal mobilisation.

    PubMed

    Lehtomäki, A; Björnsson, L

    2006-02-01

    Energy crops (willow, sugar beet and grass silage) were digested in pilot scale two-stage anaerobic digesters. The specific methane yields obtained were 0.16, 0.38 and 0.39 m3 kg(-1) added volatile solids (VSadded) for willow, sugar beet and grass, respectively, corresponding to yearly gross energy yields of 15, 53 and 26 megawatt-hours (MWh) per hectare. With grass and sugar beets as substrate, 84-85% of the harvestable methane was obtained within 30 days. In pilot scale two-stage digestion of willow and sugar beet, 56 and 85% of the laboratory scale methane yields were obtained, but digestion of grass in two-stage reactors yielded 5% more methane than digestion in laboratory scale completely mixed low solids systems, possibly due to the pH conditions favourable to hydrolysis in the two-stage system. In digestion of grass and sugar beet the liquid at the end of digestion was rich in ammonium nitrogen, and the nitrogen in the substrate was efficiently mineralised. The results show that heavy metal concentrations are not likely to limit the utilisation of residues from digestion of nonmetal accumulating crops. Efficient mobilisation of heavy metals during the acidic phase of digestion revealed the possibility of removing metals from leachate generated in two-stage anaerobic digestion of phytoextracting crops. PMID:16506517

  19. Characterizing the Anaerobic Response of Chlamydomonas reinhardtii by Quantitative Proteomics

    PubMed Central

    Terashima, Mia; Specht, Michael; Naumann, Bianca; Hippler, Michael

    2010-01-01

    The versatile metabolism of the green alga Chlamydomonas reinhardtii is reflected in its complex response to anaerobic conditions. The anaerobic response is also remarkable in the context of renewable energy because C. reinhardtii is able to produce hydrogen under anaerobic conditions. To identify proteins involved during anaerobic acclimation as well as to localize proteins and pathways to the powerhouses of the cell, chloroplasts and mitochondria from C. reinhardtii in aerobic and anaerobic (induced by 8 h of argon bubbling) conditions were isolated and analyzed using comparative proteomics. A total of 2315 proteins were identified. Further analysis based on spectral counting clearly localized 606 of these proteins to the chloroplast, including many proteins of the fermentative metabolism. Comparative quantitative analyses were performed with the chloroplast-localized proteins using stable isotopic labeling of amino acids ([13C6]arginine/[12C6]arginine in an arginine auxotrophic strain). The quantitative data confirmed proteins previously characterized as induced at the transcript level as well as identified several new proteins of unknown function induced under anaerobic conditions. These proteins of unknown function provide new candidates for further investigation, which could bring insights for the engineering of hydrogen-producing alga strains. PMID:20190198

  20. Metagenomics shows that low-energy anaerobic-aerobic treatment reactors reduce antibiotic resistance gene levels from domestic wastewater.

    PubMed

    Christgen, Beate; Yang, Ying; Ahammad, S Z; Li, Bing; Rodriquez, D Catalina; Zhang, Tong; Graham, David W

    2015-02-17

    Effective domestic wastewater treatment is among our primary defenses against the dissemination of infectious waterborne disease. However, reducing the amount of energy used in treatment processes has become essential for the future. One low-energy treatment option is anaerobic-aerobic sequence (AAS) bioreactors, which use an anaerobic pretreatment step (e.g., anaerobic hybrid reactors) to reduce carbon levels, followed by some form of aerobic treatment. Although AAS is common in warm climates, it is not known how its compares to other treatment options relative to disease transmission, including its influence on antibiotic resistance (AR) in treated effluents. Here, we used metagenomic approaches to contrast the fate of antibiotic-resistant genes (ARG) in anaerobic, aerobic, and AAS bioreactors treating domestic wastewater. Five reactor configurations were monitored for 6 months, and treatment performance, energy use, and ARG abundance and diversity were compared in influents and effluents. AAS and aerobic reactors were superior to anaerobic units in reducing ARG-like sequence abundances, with effluent ARG levels of 29, 34, and 74 ppm (198 ppm influent), respectively. AAS and aerobic systems especially reduced aminoglycoside, tetracycline, and ?-lactam ARG levels relative to anaerobic units, although 63 persistent ARG subtypes were detected in effluents from all systems (of 234 assessed). Sulfonamide and chloramphenicol ARG levels were largely unaffected by treatment, whereas a broad shift from target-specific ARGs to ARGs associated with multi-drug resistance was seen across influents and effluents. AAS reactors show promise for future applications because they can reduce more ARGs for less energy (32% less energy here), but all three treatment options have limitations and need further study. PMID:25603149

  1. Systemic Oxidative Stress Is Associated With Lower Aerobic Capacity and Impaired Skeletal Muscle Energy Metabolism in Patients With Metabolic Syndrome

    PubMed Central

    Yokota, Takashi; Kinugawa, Shintaro; Yamato, Mayumi; Hirabayashi, Kagami; Suga, Tadashi; Takada, Shingo; Harada, Kuniaki; Morita, Noriteru; Oyama-Manabe, Noriko; Kikuchi, Yasuka; Okita, Koichi; Tsutsui, Hiroyuki

    2013-01-01

    OBJECTIVE Systemic oxidative stress is associated with insulin resistance and obesity. We tested the hypothesis that systemic oxidative stress is linked to lower aerobic capacity and skeletal muscle dysfunction in metabolic syndrome (MetS). RESEARCH DESIGN AND METHODS The incremental exercise testing with cycle ergometer was performed in 14 male patients with MetS and 13 age-, sex-, and activity-matched healthy subjects. Systemic lipid peroxidation was assessed by serum thiobarbituric acid reactive substances (TBARS), and systemic antioxidant defense capacity was assessed by serum total thiols and enzymatic activity of superoxide dismutase (SOD). To assess skeletal muscle energy metabolism, we measured high-energy phosphates in the calf muscle during plantar flexion exercise and intramyocellular lipid (IMCL) in the resting leg muscle, using 31P- and 1proton-magnetic resonance spectroscopy, respectively. RESULTS Serum TBARS were elevated (12.4 ± 7.1 vs. 3.7 ± 1.1 ?mol/L; P < 0.01), and serum total thiols and SOD activity were decreased (290.8 ± 51.2 vs. 398.7 ± 105.2 ?mol/L, P < 0.01; and 22.2 ± 8.4 vs. 31.5 ± 8.5 units/L, P < 0.05, respectively) in patients with MetS compared with healthy subjects. Peak VO2 and anaerobic threshold normalized to body weight were significantly lower in MetS patients by 25 and 31%, respectively, and inversely correlated with serum TBARS (r = ?0.49 and r = ?0.50, respectively). Moreover, muscle phosphocreatine loss during exercise was 1.4-fold greater in patients with MetS (P < 0.05), and IMCL content was 2.9-fold higher in patients with MetS (P < 0.01), indicating impaired skeletal muscle energy metabolism, and these indices positively correlated with serum TBARS (r = 0.45 and r = 0.63, respectively). CONCLUSIONS Systemic oxidative stress was associated with lower aerobic capacity and impaired skeletal muscle energy metabolism in patients with MetS. PMID:23393211

  2. Benefits of supplementing an industrial waste anaerobic digester with energy crops for increased biogas production.

    PubMed

    Nges, Ivo Achu; Escobar, Federico; Fu, Xinmei; Björnsson, Lovisa

    2012-01-01

    Currently, there is increasing competition for waste as feedstock for the growing number of biogas plants. This has led to fluctuation in feedstock supply and biogas plants being operated below maximum capacity. The feasibility of supplementing a protein/lipid-rich industrial waste (pig manure, slaughterhouse waste, food processing and poultry waste) mesophilic anaerobic digester with carbohydrate-rich energy crops (hemp, maize and triticale) was therefore studied in laboratory scale batch and continuous stirred tank reactors (CSTR) with a view to scale-up to a commercial biogas process. Co-digesting industrial waste and crops led to significant improvement in methane yield per ton of feedstock and carbon-to-nitrogen ratio as compared to digestion of the industrial waste alone. Biogas production from crops in combination with industrial waste also avoids the need for micronutrients normally required in crop digestion. The batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. This was done based on the ratio of methane yields observed for laboratory batch and CSTR experiments compared to full scale CSTR digestion of industrial waste. The economy of crop-based biogas production is limited under Swedish conditions; therefore, adding crops to existing industrial waste digestion could be a viable alternative to ensure a constant/reliable supply of feedstock to the anaerobic digester. PMID:21975301

  3. An integrated approach to energy recovery from biomass and waste: Anaerobic digestion-gasification-water treatment.

    PubMed

    Milani, M; Montorsi, L; Stefani, M

    2014-06-19

    The article investigates the performance of an integrated system for the energy recovery from biomass and waste based on anaerobic digestion, gasification and water treatment. In the proposed system, the organic fraction of waste of the digestible biomass is fed into an anaerobic digester, while a part of the combustible fraction of the municipal solid waste is gasified. Thus, the obtained biogas and syngas are used as a fuel for running a cogeneration system based on an internal combustion engine to produce electric and thermal power. The waste water produced by the integrated plant is recovered by means of both forward and inverse osmosis. The different processes, as well as the main components of the system, are modelled by means of a lumped and distributed parameter approach and the main outputs of the integrated plant such as the electric and thermal power and the amount of purified water are calculated. Finally, the implementation of the proposed system is evaluated for urban areas with a different number of inhabitants and the relating performance is estimated in terms of the main outputs of the system. PMID:24946772

  4. Metabolism

    MedlinePLUS

    ... For Kids For Parents MORE ON THIS TOPIC Metabolic Syndrome Blood Test: Basic Metabolic Panel (BMP) Your Child's ... System Thyroid Disorders Diabetes Center Movie: Endocrine System Metabolic Syndrome Blood Test: Basic Metabolic Panel Blood Test: Comprehensive ...

  5. Optimizing energy harvest in wastewater treatment by combining anaerobic hydrogen producing biofermentor (HPB) and microbial fuel cell (MFC)

    Microsoft Academic Search

    Yogesh Sharma; Baikun Li

    2010-01-01

    This study focused on the optimization of energy harvest from wastewater treatment by integrating two novel biotechnologies: anaerobic hydrogen production and microbial fuel cell (MFC). The simultaneous production of hydrogen and electricity from wastewater was examined at continuous flow at different organic loading rates (OLR) by changing chemical oxygen demand (COD) and hydraulic retention time (HRT). The experimental results showed

  6. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY

    EPA Science Inventory

    The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. The fuel cell is being used for this application becau...

  7. Use of Metabolic Inhibitors to Estimate Protozooplankton Grazing and Bacterial Production in a Monomictic Eutrophic Lake with an Anaerobic Hypolimnion †

    PubMed Central

    Sanders, Robert W.; Porter, Karen G.

    1986-01-01

    Inhibitors of eucaryotes (cycloheximide and amphotericin B) and procaryotes (penicillin and chloramphenicol) were used to estimate bacterivory and bacterial production in a eutrophic lake. Bacterial production appeared to be slightly greater than protozoan grazing in the aerobic waters of Lake Oglethorpe. Use of penicillin and cycloheximide yielded inconsistent results in anaerobic water and in aerobic water when bacterial production was low. Production measured by inhibiting eucaryotes with cycloheximide did not always agree with [3H]thymidine estimates or differential filtration methods. Laboratory experiments showed that several common freshwater protozoans continued to swim and ingest bacterium-size latex beads in the presence of the eucaryote inhibitor. Penicillin also affected grazing rates of some ciliates. We recommend that caution and a corroborating method be used when estimating ecologically important parameters with specific inhibitors. PMID:16347096

  8. Utilization of biogas produced by anaerobic digestion of agro-industrial waste: Energy, economic and environmental effects.

    PubMed

    Hublin, Andrea; Schneider, Daniel Rolph; Džodan, Janko

    2014-06-24

    Anaerobic digestion of agro-industrial waste is of significant interest in order to facilitate a sustainable development of energy supply. Using of material and energy potentials of agro-industrial waste, in the framework of technical, economic, and ecological possibilities, contributes in increasing the share of energy generated from renewable energy sources. The paper deals with the benefits arising from the utilization of biogas produced by co-digestion of whey and cow manure. The advantages of this process are the profitability of the plant and the convenience in realizing an anaerobic digestion plant to produce biogas that is enabled by the benefits from the sale of electric energy at favorable prices. Economic aspects are related to the capital cost (€ 2,250,000) of anaerobic digestion treatment in a biogas plant with a 300 kW power and 510 kW heating unit in a medium size farm (450 livestock units). Considering the optimum biogas yield of 20.7 dm(3) kg(-1) of wet substrate and methane content in the biogas obtained of 79%, the anaerobic process results in a daily methane production of 2,500 kg, with the maximum power generation of 2,160,000 kWh y(-1) and heat generation of 2,400,000 kWh y(-1). The net present value (NPV), internal rate of return (IRR) and payback period for implementation of profitable anaerobic digestion process is evaluated. Ecological aspects related to carbon dioxide (CO2) and methane (CH4) emission reduction are assessed. PMID:24963093

  9. Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

    PubMed

    Wang, Yun-Kun; Pan, Xin-Rong; Sheng, Guo-Ping; Li, Wen-Wei; Shi, Bing-Jing; Yu, Han-Qing

    2015-12-01

    A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater. PMID:24880609

  10. Genome-scale comparison and constraint-based metabolic reconstruction of the facultative anaerobic Fe(III)-reducer Rhodoferax ferrireducens

    Microsoft Academic Search

    Carla Risso; Jun Sun; Kai Zhuang; Radhakrishnan Mahadevan; Robert DeBoy; Wael Ismail; Susmita Shrivastava; Heather Huot; Sagar Kothari; Sean Daugherty; Olivia Bui; Christophe H Schilling; Derek R Lovley; Barbara A Methé

    2009-01-01

    BACKGROUND: Rhodoferax ferrireducens is a metabolically versatile, Fe(III)-reducing, subsurface microorganism that is likely to play an important role in the carbon and metal cycles in the subsurface. It also has the unique ability to convert sugars to electricity, oxidizing the sugars to carbon dioxide with quantitative electron transfer to graphite electrodes in microbial fuel cells. In order to expand our

  11. Ecological network analysis of an urban energy metabolic system

    Microsoft Academic Search

    Jinyun Zhang; Yan Zhang; Zhifeng Yang

    2011-01-01

    Analysis of the structure and function of urban energy metabolic systems is an important tool to facilitate compliance with\\u000a China’s current energy-conservation policy. In this study, we used network throughflow analysis and network utility analysis\\u000a to analyze the structure of an urban energy metabolic system and the complex relationships among its components. Using weight\\u000a distributions in the network flow matrix,

  12. Actions of juglone on energy metabolism in the rat liver

    Microsoft Academic Search

    Simoni Cristina Saling; Jurandir Fernando Comar; Márcio Shigueaki Mito; Rosane Marina Peralta; Adelar Bracht

    Juglone is a phenolic compound used in popular medicine as a phytotherapic to treat inflammatory and infectious diseases. However, it also acts as an uncoupler of oxidative phosphorylation in isolated liver mitochondria and, thus, may interfere with the hepatic energy metabolism. The purpose of this work was to evaluate the effect of juglone on several metabolic parameters in the isolated

  13. Metabolic energy cost of action potential velocity.

    PubMed

    Crotty, Patrick; Sangrey, Thomas; Levy, William B

    2006-09-01

    The action potential of the unmyelinated nerve is metabolically expensive. Using the energetic cost per unit length for the biophysically modeled action potential of the squid giant axon, we analyze this cost and identify one possible optimization. The energetic cost arising from an action potential is divided into three separate components: 1) the depolarization of the rising phase; 2) the hyperpolarization of the falling phase; and 3) the largest component, the overlapping of positive and negative currents, which has no electrical effect. Using both the Hodgkin-Huxley (HH) model and an improved version of the HH model (HHSFL), we investigate the variation of these three components as a function of easily evolvable parameters, axon diameter and ion channel densities. Assuming conduction velocity is well designed for each organism, the energy component associated with the rising phase attains a minimum near the biological values of the diameter and channel densities. This optimization is explained by the membrane capacitance per unit length. The functional capacitance is the sum of the intrinsic membrane capacitance and the gating capacitance associated with the sodium channel, and this capacitance minimizes at nearly the same values of diameter and channel density. Because capacitance is temperature independent and because this result is independent of the assumed velocity, the result generalizes to unmyelinated mammalian axons. That is, channel density is arguably an evolved property that goes hand-in-hand with the evolutionary stability of the sodium channel. PMID:16554507

  14. Energy and economic assessment of anaerobic digesters and biofuels for rural waste management

    Microsoft Academic Search

    T. P. Abeles; D. F. Freedman; L. A. DeBaere; D. A. Ellsworth

    1978-01-01

    A technological and socioeconomic assessment of anaerobic digester feasibility for small to mid-size livestock operations was undertaken. Three full scale digesters and one pilot scale facility were under various degrees of monitoring and evaluation to assess design and operational problems as they affect the adoption and establishment of farm scale anaerobic digesters. Materials handling presented the greatest obstacle to satisfactory

  15. Anaerobic digestion of stillage fractions - estimation of the potential for energy recovery in bioethanol plants.

    PubMed

    Drosg, B; Fuchs, W; Meixner, K; Waltenberger, R; Kirchmayr, R; Braun, R; Bochmann, G

    2013-01-01

    Stillage processing can require more than one third of the thermal energy demand of a dry-grind bioethanol production plant. Therefore, for every stillage fraction occurring in stillage processing the potential of energy recovery by anaerobic digestion (AD) was estimated. In the case of whole stillage up to 128% of the thermal energy demand in the process can be provided, so even an energetically self-sufficient bioethanol production process is possible. For wet cake the recovery potential of thermal energy is 57%, for thin stillage 41%, for syrup 40% and for the evaporation condensate 2.5%. Specific issues for establishing AD of stillage fractions are evaluated in detail; these are high nitrogen concentrations, digestate treatment and trace element supply. If animal feed is co-produced at the bioethanol plant and digestate fractions are to be reused as process water, a sufficient quality is necessary. Most interesting stillage fractions as substrates for AD are whole stillage, thin stillage and the evaporation condensate. For these fractions process details are presented. PMID:23202552

  16. Adaptation to anaerobic metabolism in two mussel species, Mytilus edulis and Mytilus galloprovincialis, from the tidal zone at Arcachon Bay, France

    NASA Astrophysics Data System (ADS)

    de Vooys, C. G. N.

    Aspects of anaerobic metabolism were investigated in two sympatric mussel species, viz. Mytilus edulis and Mytilus galloprovincialis, living in the tidal zone in Arcachon Bay, France. Specific activities of pyruvate kinase (PK) and phosphoenolpyruvate kinase (PEP-CK) were remarkably similar in the two sympatric species and generally corresponded more closely to those observed in M. galloprovincialis in the Mediterranean than with M. edulis in the Dutch Wadden Sea. However, the values for the radio PK: PEP-CK for the two species in Arcachon Bay agreed with those of intertidal M. edulis from the Dutch Wadden Sea. Succinate accumulation during the first 24 h of anaerobicsis was about the same as in M. galloprovincialis in the Mediterranean, but decreased during the second 24 h, particularly in M. edulis, obviously due to propionate formation. Decrease in ATP concentrations in the tissues during anaerobiosis corresponded to that of intertidal M. edulis from the Dutch Wadden Sea. With the exception of specific activities of PK and PEP-CK, all properties investigated in both species were as expected in intertidal mussels.

  17. Regulation of protein and energy metabolism by the somatotropic axis

    Microsoft Academic Search

    B. H Breier

    1999-01-01

    The somatotropic axis plays a key role in the co-ordination of protein and energy metabolism during postnatal growth. This review discusses the complexity of the regulation of protein and energy metabolism by the somatotropic axis using three main examples: reduced nutrition, growth hormone (GH) treatment and insulin-like growth factor-1 (IGF-1) treatment. Decreased nutrition leads to elevated GH secretion, but it

  18. Effect of parathyroid hormone on energy metabolism of skeletal muscle

    Microsoft Academic Search

    Ryszard Baczynski; Shaul G Massry; Maria Magott; Sami El-Belbessi; Ricardo Kohan; Nachman Brautbar; G Massry

    1985-01-01

    Effect of parathyroid hormone on energy metabolism of skeletal muscle. Clinical states with primary or secondary hyperparathyroidism are associated with muscle dysfunction, suggesting that parathyroid hormone (PTH) may affect muscle metabolism. The present study examined the effect of 1–84 PTH and its amino-terminal fragment (1–34 PTH) on energy production, transfer, and utilization by skeletal muscle. Rats weighing 150 to 200

  19. Genome-scale comparison and constraint-based metabolic reconstruction of the facultative anaerobic Fe(III)-reducer Rhodoferax ferrireducens

    PubMed Central

    Risso, Carla; Sun, Jun; Zhuang, Kai; Mahadevan, Radhakrishnan; DeBoy, Robert; Ismail, Wael; Shrivastava, Susmita; Huot, Heather; Kothari, Sagar; Daugherty, Sean; Bui, Olivia; Schilling, Christophe H; Lovley, Derek R; Methé, Barbara A

    2009-01-01

    Background Rhodoferax ferrireducens is a metabolically versatile, Fe(III)-reducing, subsurface microorganism that is likely to play an important role in the carbon and metal cycles in the subsurface. It also has the unique ability to convert sugars to electricity, oxidizing the sugars to carbon dioxide with quantitative electron transfer to graphite electrodes in microbial fuel cells. In order to expand our limited knowledge about R. ferrireducens, the complete genome sequence of this organism was further annotated and then the physiology of R. ferrireducens was investigated with a constraint-based, genome-scale in silico metabolic model and laboratory studies. Results The iterative modeling and experimental approach unveiled exciting, previously unknown physiological features, including an expanded range of substrates that support growth, such as cellobiose and citrate, and provided additional insights into important features such as the stoichiometry of the electron transport chain and the ability to grow via fumarate dismutation. Further analysis explained why R. ferrireducens is unable to grow via photosynthesis or fermentation of sugars like other members of this genus and uncovered novel genes for benzoate metabolism. The genome also revealed that R. ferrireducens is well-adapted for growth in the subsurface because it appears to be capable of dealing with a number of environmental insults, including heavy metals, aromatic compounds, nutrient limitation and oxidative stress. Conclusion This study demonstrates that combining genome-scale modeling with the annotation of a new genome sequence can guide experimental studies and accelerate the understanding of the physiology of under-studied yet environmentally relevant microorganisms. PMID:19772637

  20. The techno-economic potential of renewable energy through the anaerobic digestion of microalgae.

    PubMed

    Zamalloa, Carlos; Vulsteke, Elien; Albrecht, Johan; Verstraete, Willy

    2011-01-01

    The potential of microalgae as feedstock for methane production is evaluated from a process technical and economic point of view. Production of mixed culture algae in raceway ponds on non-agricultural sites, such as landfills, was identified as a preferred approach. The potential of straightforward bio-methanation, which includes pre-concentration of microalgae and utilization of a high rate anaerobic reactor was examined based on the premises of achievable up-concentration from 0.2-0.6 kg m(-3) to 20-60 kg dry matter (DM) m(-3) and an effective bio-methanation of the concentrate at a loading rate of 20 kg DM m(-3) d(-1). The costs of biomass available for bio-methanation under such conditions were calculated to be in the range of €86-€124 ton(-1) DM. The levelized cost of energy by means of the process line "algae biomass--biogas--total energy module" would be in the order of €0.170-0.087 kWh(-1), taking into account a carbon credit of about €30 ton(-1) CO2(eq). PMID:20933389

  1. Energy metabolism in heart failure and remodelling

    PubMed Central

    Ingwall, Joanne S.

    2009-01-01

    Myocytes of the failing heart undergo impressive metabolic remodelling. The time line for changes in the pathways for ATP synthesis in compensated hypertrophy is: flux through the creatine kinase (CK) reaction falls as both creatine concentration ([Cr]) and CK activity fall; increases in [ADP] and [AMP] lead to increases in glucose uptake and utilization; fatty acid oxidation either remains the same or decreases. In uncompensated hypertrophy and in other forms of heart failure, CK flux and fatty acid oxidation are both lower; any increases in glucose uptake and utilization are not sufficient to compensate for overall decreases in the capacity for ATP supply and [ATP] falls. Metabolic remodelling is under transcriptional and post-transcriptional control. The lower metabolic reserve of the failing heart contributes to impaired contractile reserve. PMID:18987051

  2. Metabolic compensation during high energy output in fasting, lactating grey seals (Halichoerus grypus): metabolic ceilings revisited.

    PubMed Central

    Mellish, J A; Iverson, S J; Bowen, W D

    2000-01-01

    Lactation is the most energetically expensive period for female mammals and is associated with some of the highest sustained metabolic rates (SusMR) in vertebrates (reported as total energy throughput). Females typically deal with this energy demand by increasing food intake and the structure of the alimentary tract may act as the central constraint to ceilings on SusMR at about seven times resting or standard metabolic rate (SMR). However, demands of lactation may also be met by using a form of metabolic compensation such as reducing locomotor activities or entering torpor. In some phocid seals, cetaceans and bears, females fast throughout lactation and thus cannot offset the high energetic costs of lactation through increased food intake. We demonstrate that fasting grey seal females sustain, for several weeks, one of the highest total daily energy expenditures (DEE; 7.4 x SMR) reported in mammals, while progressively reducing maintenance metabolic expenditures during lactation through means not explained by reduction in lean body mass or behavioural changes. Simultaneously, the energy-exported in milk is progressively increased, associated with increased lipoprotein lipase activity in the mammary gland, resulting in greater offspring growth. Our results suggest that females use compensatory mechanisms to help meet the extraordinary energetic costs of lactation. Additionally, although the concepts of SusMR and ceilings on total DEE may be somewhat different in fasting lactating species, our data on phocid seals demonstrate that metabolic ceilings on milk energy output, in general, are not constrained by the same kind of peripheral limitations as are other energy-consuming tissues. In phocid seals, the high ceilings on DEE during lactation, coupled with metabolic compensation, are undoubtedly important factors enabling shortened lactation. PMID:10902691

  3. Energy Metabolism Disorder as a Contributing Factor of Rheumatoid Arthritis: A Comparative Proteomic and Metabolomic Study

    PubMed Central

    Zheng, Guifeng; Zou, Hai; Wang, Jian Min; Lin, Yao Yao; Chuka, Chifundo Martha; Ge, Ren Shan; Zhai, Weitao; Wang, Jian Guang

    2015-01-01

    Objectives To explore the pathogenesis of rheumatoid arthritis (RA), the different metabolites were screened in synovial fluid by metabolomics. Methods Synovial fluid from 25 RA patients and 10 normal subjects were analyzed by GC/TOF MS analysis so as to give a broad overview of synovial fluid metabolites. The metabolic profiles of RA patients and normal subjects were compared using multivariate statistical analysis. Different proteins were verified by qPCR and western blot. Different metabolites were verified by colorimetric assay kit in 25 inactive RA patients, 25 active RA patients and 20 normal subjects. The influence of hypoxia-inducible factor (HIF)-1? pathway on catabolism was detected by HIF-1? knockdown. Results A subset of 58 metabolites was identified, in which the concentrations of 7 metabolites related to energy metabolism were significantly different as shown by importance in the projection (VIP) (VIP?1) and Student’s t-test (p<0.05). In the 7 metabolites, the concentration of glucose was decreased, and the concentration of lactic acid was increased in the synovial fluid of RA patients than normal subjects verified by colorimetric assay Kit. Receiver operator characteristic (ROC) analysis shows that the concentration of glucose and lactic acid in synovial fluid could be used as dependable biomarkers for the diagnosis of active RA, provided an AUC of 0.906 and 0.922. Sensitivity and specificity, which were determined by cut-off points, reached 84% and 96% in sensitivity and 95% and 85% in specificity, respectively. The verification of different proteins identified in our previous proteomic study shows that the enzymes of anaerobic catabolism were up-regulated (PFKP and LDHA), and the enzymes of aerobic oxidation and fatty acid oxidation were down-regulated (CS, DLST, PGD, ACSL4, ACADVL and HADHA) in RA patients. The expression of HIF-1? and the enzymes of aerobic oxidation and fatty acid oxidation were decreased and the enzymes of anaerobic catabolism were increased in FLS cells after HIF-1? knockdown. Conclusion It was found that enhanced anaerobic catabolism and reduced aerobic oxidation regulated by HIF pathway are newly recognized factors contributing to the progression of RA, and low glucose and high lactic acid concentration in synovial fluid may be the potential biomarker of RA. PMID:26147000

  4. Skeletal muscle: Energy metabolism, fiber types, fatigue and adaptability

    Microsoft Academic Search

    Håkan Westerblad; Joseph D. Bruton; Abram Katz

    2010-01-01

    Skeletal muscles cope with a large range of activities, from being able to support the body weight during long periods of upright standing to perform explosive movements in response to an unexpected threat. This requires systems for energy metabolism that can provide energy during long periods of moderately increased energy consumption as well as being able to rapidly increasing the

  5. Membrane controlled anaerobic digestion

    NASA Astrophysics Data System (ADS)

    Omstead, D. R.

    In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

  6. Anaerobic treatment

    Microsoft Academic Search

    E. R. Witt; W. J. Humphrey; J. P. Cave

    1982-01-01

    This invention provides for the anaerobic treatment of acidic petrochemical wastes in an anaerobic filter at high loadings and high recycle rates. The effluent from the top of the filter passes into a gas-disengaging\\/solids-settling zone containing a quiescent body of the effluent liquid. The settled solids are withdrawn and recycled to the base of the filter together with fresh acidic

  7. Physics 4, 63 (2011) Untangling energy metabolism

    E-print Network

    2011-01-01

    chemical oscillations that occur in the metabolic process of glycolysis can be linked to a single enzyme. Subject Areas: Nonlinear Dynamics, Biological Physics A Viewpoint on: Robustness of glycolysis in yeast essential precursor metabo- lites for the buildup of biomass. Glycolysis is also interesting from

  8. Skeletal muscle: energy metabolism, fiber types, fatigue and adaptability.

    PubMed

    Westerblad, Håkan; Bruton, Joseph D; Katz, Abram

    2010-11-01

    Skeletal muscles cope with a large range of activities, from being able to support the body weight during long periods of upright standing to perform explosive movements in response to an unexpected threat. This requires systems for energy metabolism that can provide energy during long periods of moderately increased energy consumption as well as being able to rapidly increasing the rate of energy production more than 100-fold in response to explosive contractions. In this short review we discuss how muscles can deal with these divergent demands. We first outline the major energy metabolism pathways in skeletal muscle. Next we describe metabolic differences between different muscle fiber types. Contractile performance declines during intense activation, i.e. fatigue develops, and we discuss likely underlying mechanisms. Finally, we discuss the ability of muscle fibers to adapt to altered demands, and mechanisms behind these adaptations. The accumulated experimental evidence forces us to conclude that most aspects of energy metabolism involve multiple and overlapping signaling pathways, which indicates that the control of energy metabolism is too important to depend on one single molecule or mechanism. PMID:20580710

  9. Automatic purification of animal wastewater by dual means of energy-retaining anaerobic fermentation and ultrafiltration

    SciTech Connect

    Kobayashi, Shigeki; Masuda, Yoshiko (Meiji Univ., Kawasaki (Japan)); Etou, Yasushi (Sanshin Technological Co., Ltd., Yokohama (Japan))

    1993-11-01

    For the purpose of purifying animal wastewater and recovering energy during the operation, an automatic bench-scale unit was manufactured and operated. It consisted of three pieces of an anaerobic fermentation digester, a sedimentation tank and an ultrafiltration module. The digester was equipped with fixed bacteria beds(bioreactor) and tape heaters. The sedimentation tank was equipped with a heat exchanger, through which fresh slurry passed. During automatic operations the slurry samples were taken out before, during and after the operation, and turbidity and organic matter contents were analyzed. Comparing nylon mesh, chips of vinyl chloride pipe and crushed cement blocks, the crushed blocks were recognized best as a fixed bacteria bed. In the operating process, the supernatant fluid in the sedimentation tank was sent to the ultrafiltration module. After filtration a daily reverse cleansing was performed. All the operations worked according to the command programmed in the Controller PL40M III. The average removal rates of organic matters in the compound slurry by the dual operations were as follows: 76.6% T-S, 100.0% T-SS, 92.6% COD, 96.5% BOD, 86.8% NH[sub 4]-N, 69.0% T-N, and 98.8% T-P. The result of pre-heating fresh slurry by effluent from the digester was also evaluated. 14 refs., 4 figs., 6 tabs.

  10. Anaerobic Digestion of Primary Sewage Effluent

    E-print Network

    Anaerobic Digestion of Primary Sewage Effluent: Significant Energy Savings over Traditional Activated Sludge Treatment This report presents results for an anaerobic digestion system operated;Anaerobic Digestion of Primary Sewage Effluent Prepared for the U.S. Department of Energy Office

  11. Dissecting the energy metabolism in Mycoplasma pneumoniae through genome-scale metabolic modeling

    PubMed Central

    Wodke, Judith A H; Pucha?ka, Jacek; Lluch-Senar, Maria; Marcos, Josep; Yus, Eva; Godinho, Miguel; Gutiérrez-Gallego, Ricardo; dos Santos, Vitor A P Martins; Serrano, Luis; Klipp, Edda; Maier, Tobias

    2013-01-01

    Mycoplasma pneumoniae, a threatening pathogen with a minimal genome, is a model organism for bacterial systems biology for which substantial experimental information is available. With the goal of understanding the complex interactions underlying its metabolism, we analyzed and characterized the metabolic network of M. pneumoniae in great detail, integrating data from different omics analyses under a range of conditions into a constraint-based model backbone. Iterating model predictions, hypothesis generation, experimental testing, and model refinement, we accurately curated the network and quantitatively explored the energy metabolism. In contrast to other bacteria, M. pneumoniae uses most of its energy for maintenance tasks instead of growth. We show that in highly linear networks the prediction of flux distributions for different growth times allows analysis of time-dependent changes, albeit using a static model. By performing an in silico knock-out study as well as analyzing flux distributions in single and double mutant phenotypes, we demonstrated that the model accurately represents the metabolism of M. pneumoniae. The experimentally validated model provides a solid basis for understanding its metabolic regulatory mechanisms. PMID:23549481

  12. Effects of exercise at individual anaerobic threshold and maximal fat oxidation intensities on plasma levels of nesfatin-1 and metabolic health biomarkers.

    PubMed

    Mohebbi, Hamid; Nourshahi, Maryam; Ghasemikaram, Mansour; Safarimosavi, Saleh

    2015-03-01

    Exercise is recognized as an effective method of weight management and short-term appetite regulation tool. The effect of different exercise intensities on appetite regulation hormones in healthy overweight participants has not been intensively studied. The aim of this study was to examine the influence of exercise at individual anaerobic threshold (IAT) and maximal fat oxidation (Fatmax) intensities on the nesfatin-1 response and metabolic health biomarkers in overweight men. Nine healthy overweight males (age, 23.1?±?1.1 years) volunteered in this study in a counterbalanced order. Blood samples were obtained before, immediately after, and following the first 45 min of recovery for measuring plasma variables. There was significant decrease in plasma levels of nesfatin-1 and leptin after exercise at the IAT intensity which remained lower than baseline following 45 min of recovery. However, nesfatin-1 and leptin levels did not change significantly in any time courses of Fatmax intensity (P?>?0.09). Plasma interleukin-6 (IL-6) concentration increased during exercise in both intensities (P?

  13. Energy metabolism in acute and chronic renal failure?3

    Microsoft Academic Search

    Bruno Schneeweiss; Wolfgang Graninger; Felix Siockenhuber; Wilfred Drum; Peter Ferenci; Sabine Eichinger; Georg Grimm; Anton N Laggner; Kurt Lenz

    Energy metabolism was measured by mdi- rect calorimetry in 86 patients with various forms of renal fail- ure and in 24 control subjects. In patients with acute renal fail- ure with sepsis, oxygen consumption, carbon dioxide produc- tion, and resting energy expenditure were increased ( P < 0.05). In other groups with renal failure (acute renal failure without sepsis, chronic

  14. Environmental effects on nutrient and energy metabolism in pigs

    Microsoft Academic Search

    C. Wenk

    1998-01-01

    Besides the genetic predisposition and the dietary supply of nutrients, environmental factors affect the performance of the pig. Environment can affect the nutrient composition and availability of the feed. It can also influence appetite and therefore the feed intake. Furthermore, nutrient and energy utilization on the level of digestion and intermediate metabolism can depend on environmental factors. Especially the energy

  15. Some insights into energy metabolism for osmoregulation in fish

    Microsoft Academic Search

    Yung-Che Tseng; Pung-Pung Hwang

    2008-01-01

    A sufficient and timely energy supply is a prerequisite for the operation of iono- and osmoregulatory mechanisms in fish. Measurements of whole-fish or isolated-gill (or other organs) oxygen consumption have demonstrated regulation of the energy supply during acclimation to different osmotic environments, and such regulation is dependent on species, the situation of acclimation or acclimatization, and life habits. Carbohydrate metabolism

  16. Effects of monocrotaline on energy metabolism in the rat liver.

    PubMed

    Mingatto, Fábio Erminio; Maioli, Marcos Antonio; Bracht, Adelar; Ishii-Iwamoto, Emy Luiza

    2008-11-10

    Monocrotaline (MCT) is a pyrrolizidine alkaloid present in the plants of the Crotalaria species that causes cytotoxicity and genotoxicity in animals and humans, and it is hepatically metabolized to the alkylating agent dehydromonocrotaline by cytochrome P-450. The exact cellular and molecular mechanisms of MCT-induced tissue injury remain unclear. We previously demonstrated that dehydromonocrotaline, but not monocrotaline, inhibits the activity of NADH-dehydrogenase at micromolar concentrations in isolated liver mitochondria, an effect associated with significantly reduced ATP synthesis. Impairment of energy metabolism is expected to lead to several alterations in cell metabolism. In this work, the action of different concentrations of monocrotaline (250, 500, and 750microM) on energy metabolism-linked parameters was investigated in isolated perfused rat livers. In the fed state, monocrotaline increased glycogenolysis and glycolysis, whereas in the livers of fasted rats, it decreased gluconeogenesis and urea synthesis from l-alanine. These metabolic alterations were only found in livers of phenobarbital-treated rats, indicating that active metabolites including dehydromonocrotaline were responsible for the observed activity. Our findings indicate that hepatic metabolic changes may be implicated, partly at least, in the hepatotoxicity of monocrotaline in animals and humans. PMID:18835426

  17. The anaerobic digestion process

    SciTech Connect

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  18. Anammoxosomes of Anaerobic Ammonium-oxidizing Planctomycetes

    Microsoft Academic Search

    John A. Fuerst; Richard Webb; Laura van Niftrik; Mike S. M. Jetten; Marc Strous

    2006-01-01

    Anammoxosomes are unique metabolically significant compartments of planctomycetes performing the anammox process. These bacteria carry out Anaerobic\\u000a Ammonium Oxidation, a chemolithotrophic\\u000a and autotrophic metabolism. They comprise Candidatus genera “Brocadia”,\\u000a “Kuenenia” and “Scalindua”, mostly from wastewater treatment bioreactors or marine\\u000a anaerobic habitats and none of which are yet in pure culture. Like cells of other planctomycetes, anammox\\u000a species possess a shared planctomycete cell

  19. Mitochondrial DNA variation in human metabolic rate and energy expenditure

    PubMed Central

    Tranah, Gregory J.; Manini, Todd M.; Lohman, Kurt K.; Nalls, Michael A.; Kritchevsky, Stephen; Newman, Anne B.; Harris, Tamara B.; Miljkovic, Iva; Biffi, Alessandro; Cummings, Steven R.; Liu, Yongmei

    2014-01-01

    The role of climate in driving selection of mtDNA as Homo sapiens migrated out of Africa into Eurasia remains controversial. We evaluated the role of mtDNA variation in resting metabolic rate (RMR) and total energy expenditure (TEE) among 294 older, community-dwelling African and European American adults from the Health, Aging and Body Composition Study. Common African haplogroups L0, L2 and L3 had significantly lower RMRs than European haplogroups H, JT and UK with haplogroup L1 RMR being intermediate to these groups. This study links mitochondrial haplogroups with ancestry-associated differences in metabolic rate and energy expenditure. PMID:21586348

  20. Inhibition of anaerobic digestion process: A review

    Microsoft Academic Search

    Ye Chen; Jay J. Cheng; Kurt S. Creamer

    2008-01-01

    Anaerobic digestion is an attractive waste treatment practice in which both pollution control and energy recovery can be achieved. Many agricultural and industrial wastes are ideal candidates for anaerobic digestion because they contain high levels of easily biodegradable materials. Problems such as low methane yield and process instability are often encountered in anaerobic digestion, preventing this technique from being widely

  1. [Energy metabolism and myocardial function in myocardiodystrophy].

    PubMed

    Temirova, K V; Kurlygina, L A; Zavodskaia, I S; Novikova, N A

    1976-09-01

    A total of 92 patients with chronic tonsilitis and cardiovascular changes were subjected to clinical observations, ECG analysis, potassium and nitroglycerine tests, and studies of the lactic acid level and creatinekinase activity as indces of myocardial metabolism. The examinations were conducted prior to and following tonsillectomy. In a majority of patients a correlation was revealed between the degree of ECG changes and the serum lactic acid level, as well as between the ECG improvement and a reduction of the lactic acid level following tonsillectomy. Three stages of tonsillogenic myocardiodystrophy were distinguished. The obtained data indicate the rationale of the used tests for the evaluation of the myocardial meabolism alterations and of the efficacy of treatment of chronic tonsillitis patients. PMID:1011536

  2. Therapeutic implications of targeting energy metabolism in breast cancer.

    PubMed

    Sakharkar, Meena K; Shashni, Babita; Sharma, Karun; Dhillon, Sarinder K; Ranjekar, Prabhakar R; Sakharkar, Kishore R

    2013-01-01

    PPARs are ligand activated transcription factors. PPAR? agonists have been reported as a new and potentially efficacious treatment of inflammation, diabetes, obesity, cancer, AD, and schizophrenia. Since cancer cells show dysregulation of glycolysis they are potentially manageable through changes in metabolic environment. Interestingly, several of the genes involved in maintaining the metabolic environment and the central energy generation pathway are regulated or predicted to be regulated by PPAR?. The use of synthetic PPAR? ligands as drugs and their recent withdrawal/restricted usage highlight the lack of understanding of the molecular basis of these drugs, their off-target effects, and their network. These data further underscores the complexity of nuclear receptor signalling mechanisms. This paper will discuss the function and role of PPAR? in energy metabolism and cancer biology in general and its emergence as a promising therapeutic target in breast cancer. PMID:23431283

  3. Therapeutic Implications of Targeting Energy Metabolism in Breast Cancer

    PubMed Central

    Sakharkar, Meena K.; Shashni, Babita; Sharma, Karun; Dhillon, Sarinder K.; Ranjekar, Prabhakar R.; Sakharkar, Kishore R.

    2013-01-01

    PPARs are ligand activated transcription factors. PPAR? agonists have been reported as a new and potentially efficacious treatment of inflammation, diabetes, obesity, cancer, AD, and schizophrenia. Since cancer cells show dysregulation of glycolysis they are potentially manageable through changes in metabolic environment. Interestingly, several of the genes involved in maintaining the metabolic environment and the central energy generation pathway are regulated or predicted to be regulated by PPAR?. The use of synthetic PPAR? ligands as drugs and their recent withdrawal/restricted usage highlight the lack of understanding of the molecular basis of these drugs, their off-target effects, and their network. These data further underscores the complexity of nuclear receptor signalling mechanisms. This paper will discuss the function and role of PPAR? in energy metabolism and cancer biology in general and its emergence as a promising therapeutic target in breast cancer. PMID:23431283

  4. ENERGY AND ECONOMIC ASSESSMENT OF ANAEROBIC DIGESTERS AND BIOFUELS FOR RURAL WASTE MANAGEMENT

    EPA Science Inventory

    A technological and socioeconomic assessment of anaerobic digester feasibility for small to mid-size livestock operations was undertaken. Three full scale digesters and one pilot scale facility were under various degrees of monitoring and evaluation to assess design and operation...

  5. Digestive and Metabolic Utilization of Feed Energy in Swine: Application to Energy Evaluation Systems

    Microsoft Academic Search

    Jean Noblet

    2000-01-01

    Noblet, J. 2000. Digestive and metabolic utilization of feed energy in swine: Application to energy evaluation systems. J. Appl. Anim. Res., 17: 113–132.Feeds can be attributed different energy values according to, first, the step considered in energy utilization (DE: digestible energy, ME: metabolisable energy and NE: net energy) and, second, the method used for estimation at each step. This paper

  6. Inorganic Polyphosphate and Energy Metabolism in Mammalian Cells*

    PubMed Central

    Pavlov, Evgeny; Aschar-Sobbi, Roozbeh; Campanella, Michelangelo; Turner, Raymond J.; Gómez-García, María R.; Abramov, Andrey Y.

    2010-01-01

    Inorganic polyphosphate (poly P) is a polymer made from as few as 10 to several hundred phosphate molecules linked by phosphoanhydride bonds similar to ATP. Poly P is ubiquitous in all mammalian organisms, where it plays multiple physiological roles. The metabolism of poly P in mammalian organisms is not well understood. We have examined the mechanism of poly P production and the role of this polymer in cell energy metabolism. Poly P levels in mitochondria and intact cells were estimated using a fluorescent molecular probe, 4?,6-diamidino-2-phenylindole. Poly P levels were dependent on the metabolic state of the mitochondria. Poly P levels were increased by substrates of respiration and in turn reduced by mitochondrial inhibitor (rotenone) or an uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone). Oligomycin, an inhibitor of mitochondrial ATP-synthase, blocked the production of poly P. Enzymatic depletion of poly P from cells significantly altered the rate of ATP metabolism. We propose the existence of a feedback mechanism where poly P production and cell energy metabolism regulate each other. PMID:20124409

  7. Modeling Brain Energy Metabolism and Function: A Multiparametric Monitoring Approach

    Microsoft Academic Search

    Larisa Vatova; Sigal Meilin; Tamar Manor

    Mathematical modeling of brain function is an important tool needed for a better understanding of experimental results and clinical situations. In the present study, we are constructing and testing a mathematical model capable of simulating changes in brain energy metabolism that develop in real time under various pathophysiological conditions. The model incorporates the following pa- rameters: cerebral blood flow, partial

  8. Fatty Acids in Energy Metabolism of the Central Nervous System

    PubMed Central

    Orynbayeva, Zulfiya; Vavilin, Valentin; Lyakhovich, Vyacheslav

    2014-01-01

    In this review, we analyze the current hypotheses regarding energy metabolism in the neurons and astroglia. Recently, it was shown that up to 20% of the total brain's energy is provided by mitochondrial oxidation of fatty acids. However, the existing hypotheses consider glucose, or its derivative lactate, as the only main energy substrate for the brain. Astroglia metabolically supports the neurons by providing lactate as a substrate for neuronal mitochondria. In addition, a significant amount of neuromediators, glutamate and GABA, is transported into neurons and also serves as substrates for mitochondria. Thus, neuronal mitochondria may simultaneously oxidize several substrates. Astrocytes have to replenish the pool of neuromediators by synthesis de novo, which requires large amounts of energy. In this review, we made an attempt to reconcile ?-oxidation of fatty acids by astrocytic mitochondria with the existing hypothesis on regulation of aerobic glycolysis. We suggest that, under condition of neuronal excitation, both metabolic pathways may exist simultaneously. We provide experimental evidence that isolated neuronal mitochondria may oxidize palmitoyl carnitine in the presence of other mitochondrial substrates. We also suggest that variations in the brain mitochondrial metabolic phenotype may be associated with different mtDNA haplogroups. PMID:24883315

  9. PGC-1{alpha}: a key regulator of energy metabolism

    NSDL National Science Digital Library

    Huiyun Liang (University of Texas Health Science Center Department of Cellular and Structural Biology, Barshop Institute for Longevity and Aging Studies)

    2006-12-01

    Peroxisome proliferator-activated receptor-{gamma} coactivator (PGC)-1{alpha} is a member of a family of transcription coactivators that plays a central role in the regulation of cellular energy metabolism. This makes it an inviting target for pharmacological intervention in the treatment of obesity and Type 2 diabetes.

  10. ENERGY METABOLISM AND THERMOREGULATION IN THE NEWBORN CALF

    E-print Network

    Boyer, Edmond

    calves 1. Variations of rectal temperature, thermolysis and thermogenesis 1.1. Variations with age Rectal at around 38.8 °C 4 or 5 h after (per- sonal results, fig. 1). In cold exposed calves rectal temperaturesENERGY METABOLISM AND THERMOREGULATION IN THE NEWBORN CALF M. VERMOREL C. DARDILLAT2 J. VERNET1

  11. Metabolic adaptation for low energy throughput in orangutans

    E-print Network

    Pontzer, Herman

    Metabolic adaptation for low energy throughput in orangutans Herman Pontzera,1 , David A. Raichlenb Indianapolis Zoo, Indianapolis, IN 46222; d Krasnow Institute for Advanced Studies, George Mason University, Switzerland; and f Sumatran Orangutan Conservation Programme, PanEco Foundation, Medan 20154, Indonesia Edited

  12. Anaerobic respiration in the polychaete Euzonus (Thoracophelia) mucronata

    Microsoft Academic Search

    E. G. Ruby; D. L. Fox

    1976-01-01

    The intertidal polychaete Euzonus mucronata (Treadwell) is found in great numbers within beach sands that undergo periodic anoxia. Short-term exposures (2 to 4 h) to anaerobicity are withstood through the use of a supply of oxyhemoglobin to support continued aerobic metabolism. Longer periods of environmental anoxia activate an anaerobic metabolism capable of sustaining life for up to 20 days, and

  13. Response of anaerobic ammonium-oxidizing bacteria to hydroxylamine

    Microsoft Academic Search

    Maarten J. Van De Graaf; Boran Kartal; Cristian Picioreanu; Mike S. M. Jetten

    2008-01-01

    Anaerobic ammonium oxidation is a recent addition to the microbial nitrogen cycle, and its metabolic pathway, including the production and conversion of its intermediate hydrazine, is not well understood. Therefore, the effect of hydroxylamine addition on the hydrazine metabolism of anaerobic ammonium-oxidizing (anammox) bacteria was studied both experimentally and by mathematical modeling. It was observed that hydroxylamine was disproportionated biologically

  14. Economic viability of anaerobic digestion

    SciTech Connect

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  15. Economic viability of anaerobic digestion

    SciTech Connect

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1995-11-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters-type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates-define the investment and operating costs of anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters in somewhat higher than that of anaerobic digestion, but the investment costs 11/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  16. Energy metabolism, testosterone and corticosterone in white-crowned sparrows

    Microsoft Academic Search

    M. Wikelski; S. Lynn; J. C. Breuner; J. C. Wingfield; G. J. Kenagy

    1999-01-01

    The influence of the steroid hormones testosterone and corticosterone on energy metabolism and activity of birds is largely\\u000a enigmatic. We measured resting metabolic rate during night and day in 12 long-term castrated and 12 intact male white-crowned\\u000a sparrows (Zonotrichia leucophrys gambelii) under short-day (8:16 SD), long-day (20:4 LD), LD+testosterone implant and LD?testosterone implant conditions. Each male\\u000a was sequentially measured under

  17. Regulation of hepatic energy metabolism and gluconeogenesis by BAD.

    PubMed

    Giménez-Cassina, Alfredo; Garcia-Haro, Luisa; Choi, Cheol Soo; Osundiji, Mayowa A; Lane, Elizabeth A; Huang, Hu; Yildirim, Muhammed A; Szlyk, Benjamin; Fisher, Jill K; Polak, Klaudia; Patton, Elaura; Wiwczar, Jessica; Godes, Marina; Lee, Dae Ho; Robertson, Kirsten; Kim, Sheene; Kulkarni, Ameya; Distefano, Alberto; Samuel, Varman; Cline, Gary; Kim, Young-Bum; Shulman, Gerald I; Danial, Nika N

    2014-02-01

    The homeostatic balance of hepatic glucose utilization, storage, and production is exquisitely controlled by hormonal signals and hepatic carbon metabolism during fed and fasted states. How the liver senses extracellular glucose to cue glucose utilization versus production is not fully understood. We show that the physiologic balance of hepatic glycolysis and gluconeogenesis is regulated by Bcl-2-associated agonist of cell death (BAD), a protein with roles in apoptosis and metabolism. BAD deficiency reprograms hepatic substrate and energy metabolism toward diminished glycolysis, excess fatty acid oxidation, and exaggerated glucose production that escapes suppression by insulin. Genetic and biochemical evidence suggests that BAD's suppression of gluconeogenesis is actuated by phosphorylation of its BCL-2 homology (BH)-3 domain and subsequent activation of glucokinase. The physiologic relevance of these findings is evident from the ability of a BAD phosphomimic variant to counteract unrestrained gluconeogenesis and improve glycemia in leptin-resistant and high-fat diet models of diabetes and insulin resistance. PMID:24506868

  18. Anaerobic treatment

    SciTech Connect

    Witt, E.R.; Humphrey, W.J.; Cave, J.P.

    1982-12-28

    This invention provides for the anaerobic treatment of acidic petrochemical wastes in an anaerobic filter at high loadings and high recycle rates. The effluent from the top of the filter passes into a gas-disengaging/solids-settling zone containing a quiescent body of the effluent liquid. The settled solids are withdrawn and recycled to the base of the filter together with fresh acidic waste and an inorganic alkaline material (preferably magnesium oxide or carbonate) to maintain a neutral pH. The liquid portion of the effluent is sent to an aerobic digester to remove the rest of the organic material, which is used to support the growth of bacteria and fed back to the anaerobic system.

  19. 13C NMR spectroscopy applications to brain energy metabolism

    PubMed Central

    Rodrigues, Tiago B.; Valette, Julien; Bouzier-Sore, Anne-Karine

    2013-01-01

    13C nuclear magnetic resonance (NMR) spectroscopy is the method of choice for studying brain metabolism. Indeed, the most convincing data obtained to decipher metabolic exchanges between neurons and astrocytes have been obtained using this technique, thus illustrating its power. It may be difficult for non-specialists, however, to grasp thefull implication of data presented in articles written by spectroscopists. The aim of the review is, therefore, to provide a fundamental understanding of this topic to facilitate the non-specialists in their reading of this literature. In the first part of this review, we present the metabolic fate of 13C-labeled substrates in the brain in a detailed way, including an overview of some general neurochemical principles. We also address and compare the various spectroscopic strategies that can be used to study brain metabolism. Then, we provide an overview of the 13C NMR experiments performed to analyze both intracellular and intercellular metabolic fluxes. More particularly, the role of lactate as a potential energy substrate for neurons is discussed in the light of 13C NMR data. Finally, new perspectives and applications offered by 13C hyperpolarization are described. PMID:24367329

  20. Energy and protein metabolism in sarcoma patients.

    PubMed Central

    Shaw, J H; Humberstone, D M; Wolfe, R R

    1988-01-01

    We have performed a series of isotopic infusions both in normal volunteers (N = 16) and in sarcoma patients (N = 7). Using the primed-constant infusion of stable or radioisotopes we have determined the rates of glucose turnover, glucose oxidation, glucose recycling, and net protein catabolism (NPC). In addition, we have measured VO2 and VCO2. The values for VCO2 and VO2 were higher in the patients than in the volunteers (mean VO2 values in volunteers and patients: 107 +/- 13 and 158 +/- 13 mumol/kg/min, respectively). The basal rate of glucose appearance in the sarcoma patients was twice the value seen in the volunteers (28.3 +/- 3.5 vs. 13.9 +/- 0.3 mumol/kg/min). Glucose infusion in the volunteers resulted in virtually total suppression of endogenous glucose production, while in the patients glucose infusion induced only a 30% suppression of endogenous glucose production (p less than 0.01). The rate of glucose clearance in the patients was approximately twice the value seen in the volunteers [5.4 +/- 1.0 vs. 2.7 +/- 0.1 mL/kg/min (p less than 0.01)]. The per cent of glucose uptake oxidized in the patients was significantly less than in the volunteers [22% vs. 36% (p less than 0.05)], and the per cent of glucose uptake that was recycled was significantly higher in the patients [55% vs. 10% (p less than 0.01)]. In addition, the basal rate of net protein loss was increased twofold in the patients [3.2 +/- 0.5 vs. 1.4 +/- 0.4 g (protein)/kg/d (p less than 0.01)], and in contrast to the situation in the volunteers there was no suppression in the rate of net protein loss when the patients were infused with glucose. The basal insulin concentration and the insulin response to glucose infusion in the patients were similar to that of the volunteers, but the plasma cortisol level was similar in volunteers and in the patients (p less than 0.05). We conclude from these studies the following: (1) Sarcoma patients have significantly elevated rates of glucose production and glucose clearance, but they have an impaired capacity to directly oxidize either endogenous or infused glucose, coupled with an increased rate of glucose recycling. (2) Sarcoma patients have an elevated metabolic rate and are catabolic. In addition, in contrast with normal volunteers, glucose infusion does not result in a suppression of protein loss. PMID:3422801

  1. ECO-ENERGY DEMONSTRATION MODEL: ANAEROBIC DIGESTION, ALGAE AND ENERGY PROSPERITY

    EPA Science Inventory

    For the project, we: Designed and constructed an ecological energy model system. Investigated and characterized locally abundant agricultural and domestic waste resources that can have significant environmental impacts (dairy manure, poultry m...

  2. Metabolism

    MedlinePLUS

    ... Some metabolic diseases and conditions include: Hyperthyroidism (pronounced: hi-per-THIGH-roy-dih-zum). Hyperthyroidism is caused ... or through surgery or radiation treatments. Hypothyroidism (pronounced: hi-po-THIGH-roy-dih-zum) . Hypothyroidism is caused ...

  3. Radiogenic metabolism: an alternative cellular energy source

    Microsoft Academic Search

    M. S. Benford

    2001-01-01

    The concept of ‘healing energy’ is commonly used in complementary and alternative medicine; however, efforts to define this concept using contemporary scientific theory, and measure it using modern scientific methods, have been limited to date. Recent experimental testing by Benford et al. observed a uniform, substantial, and consistent decrease in gamma radiation during alternative healing sessions, thus supporting a new

  4. How anaerobic is the Wingate Anaerobic Test for humans?

    Microsoft Academic Search

    R. Beneke; C. Pollmann; I. Bleif; R. Leithäuser; M. Hütler

    2002-01-01

    .   The Wingate Anaerobic Test (WAnT) is generally used to evaluate anaerobic cycling performance, but knowledge of the metabolic\\u000a profile of WAnT is limited. Therefore the energetics of WAnT was analysed with respect to working efficiency and performance.\\u000a A group of 11 male subjects [mean (SD), age 21.6 (3.8) years, height 178.6 (6.6) cm, body mass 82.2 (12.1) kg] performed a\\u000a maximal incremental exercise test and a

  5. Potential Application of Anaerobic Extremophiles for Hydrogen Production

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    During substrate fermentation many anaerobes produce the hydrogen as a waste product, which often regulates the growth of the cultures as an inhibitor. In nature the hydrogen is usually removed from the ecosystem due to its physical properties or by consumption of hydrogen by secondary anaerobes, which sometimes behave as competitors for electron donors as is seen in the classical example in anaerobic microbial communities via the interaction between methanogens and sulfate- or sulfur- reducers. It was demonstrated previously on mixed cultures of anaerobes at neutral pH that bacterial hydrogen production could provide an alternative energy source. But at neutral pH the original cultures can easily be contaminated by methanogens, a most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and the cultivation of human pathogens on a global scale is very dangerous. In our laboratory, experiments with obligately alkaliphilic bacteria that excrete hydrogen as the end metabolic product were performed at different temperature regimes. Mesophilic and moderately thermophilic bacterial cultures have been studied and compared for the most effective hydrogen production. For high-mineralized media with pH 9.5-10.0 not many methanogens are known to exist. Furthermore, the development of pathogenic contaminant microorganisms is virtually impossible: carbonate-saturated solutions are used as antiseptics in medicine. Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as most safe process for global Scale industry in future. Here we present experimental data on the rates of hydrogen productivity for mesophilic, alkaliphilic, obligately anaerobic bacterium Spirocheta americana ASpG1 and moderately thermophilic, alkaliphilic, facultative anaerobe Anoxybacillus pushchinoensis K1 and discuss the potential implications for alternative energy sources.

  6. Energy metabolism in Bardet–Biedl syndrome

    Microsoft Academic Search

    C Grace; P Beales; C Summerbell; S A Jebb; A Wright; D Parker; P Kopelman

    2003-01-01

    INTRODUCTION: Obesity is a consistent presenting feature of the Bardet–Biedl syndrome (BBS), a hereditary disorder caused by a single gene defect. This contrasts sharply with general obesity which, despite a strong hereditary component, has a multifactorial aetiology. For BBS, the phenotypic characterisation of the components of energy balance and the implications for their management remains relatively uninvestigated.OBJECTIVE: A case–control study

  7. DEHALOGENATION: A NOVEL PATHWAY FOR THE ANAEROBIC BIODEGRADATION OF HALOAROMATIC COMPOUNDS

    EPA Science Inventory

    Microorganisms of lake sediment and sewage sludge anaerobically metabolize halobenzoates by a novel pathway. The primary degradative event was loss of the aryl halide without the alteration of the aromatic ring. Dehalogenation required strict anaerobic conditions and depended on ...

  8. Anaerobic Diegestion: Applying Anaerobic Technology to Satisfy Livestock Waste Treatment Regulations

    Microsoft Academic Search

    Teresa Shiflett

    Anaerobic digestion has been proven to be a beneficial application for treating livestock wastes. Benefits of anaerobic digestion include; reduction of odors, renewable energy in the form of biogas, stabilization and pollutant removal, and retention of nutrients for land application. Conventional digesters have been an established method of anaerobic treatment for a long period of time. However, they have many

  9. Role of aquaglyceroporins and caveolins in energy and metabolic homeostasis.

    PubMed

    Méndez-Giménez, Leire; Rodríguez, Amaia; Balaguer, Inmaculada; Frühbeck, Gema

    2014-11-01

    Aquaglyceroporins and caveolins are submicroscopic integral membrane proteins that are particularly abundant in many mammalian cells. Aquaglyceroporins (AQP3, AQP7, AQP9 and AQP10) encompass a subfamily of aquaporins that allow the movement of water, but also of small solutes, such as glycerol, across cell membranes. Glycerol constitutes an important metabolite as a substrate for de novo synthesis of triacylglycerols and glucose as well as an energy substrate to produce ATP via the mitochondrial oxidative phosphorylation. In this sense, the control of glycerol influx/efflux in metabolic organs by aquaglyceroporins plays a crucial role with the dysregulation of these glycerol channels being associated with metabolic diseases, such as obesity, insulin resistance, non-alcoholic fatty liver disease and cardiac hypertrophy. On the other hand, caveolae have emerged as relevant plasma membrane sensors implicated in a wide range of cellular functions, including endocytosis, apoptosis, cholesterol homeostasis, proliferation and signal transduction. Caveolae-coating proteins, namely caveolins and cavins, can act as scaffolding proteins within caveolae by concentrating signaling molecules involved in free fatty acid and cholesterol uptake, proliferation, insulin signaling or vasorelaxation, among others. The importance of caveolae in whole-body homeostasis is highlighted by the link between homozygous mutations in genes encoding caveolins and cavins with metabolic diseases, such as lipodystrophy, dyslipidemia, muscular dystrophy and insulin resistance in rodents and humans. The present review focuses on the role of aquaglyceroporins and caveolins on lipid and glucose metabolism, insulin secretion and signaling, energy production and cardiovascular homeostasis, outlining their potential relevance in the development and treatment of metabolic diseases. PMID:25008241

  10. [Oxygraphic evaluation of energy metabolism in isolated hepatocytes].

    PubMed

    Cervinková, Zuzana; Kucera, Otto; Lotková, Halka; Drahota, Zdenek; Houstek, Josef

    2002-01-01

    The paper presents a protocol for the evaluation of energy metabolism in hepatocytes with the aid of high-resolution oxygraphy in permeabilized cells. Optimal conditions are suggested for the isolation of hepatocytes from the hepatic tissue of the rat and the proper technique for control of their structural integrity. Our work describes in detail the experimental schemes for oxygraphic evaluation of the individual enzyme complexes of the respiratory chain (Complex I, II, IV) and methods for the assessment of the mitochondrial function of phosphorylation using the respiratory control index and oligomycin inhibitory effect on ADP-activated respiration. On the example of oxidative damage of hepatocytes by tert-butylhydroperoxide, we demonstrate the utility of oxygraphy in the diagnostics of pathologic conditions caused by disturbances in energy metabolism of the cell. PMID:19569581

  11. Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

    Microsoft Academic Search

    Kennan Kellaris Salinero; Keith Keller; William S Feil; Helene Feil; Stephan Trong; Genevieve Di Bartolo; Alla Lapidus

    2009-01-01

    BACKGROUND: Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. RESULTS: The a priori prediction that

  12. Modeling Brain Energy Metabolism and Function: A Multiparametric Monitoring Approach

    Microsoft Academic Search

    Larisa Vatov; Ziv Kizner; Eytan Ruppin; Sigal Meilin; Tamar Manor; Avraham Mayevsky

    2006-01-01

    Mathematical modeling of brain function is an important tool needed for a better understanding of experimental results and\\u000a clinical situations. In the present study, we are constructing and testing a mathematical model capable of simulating changes\\u000a in brain energy metabolism that develop in real time under various pathophysiological conditions. The model incorporates the\\u000a following parameters: cerebral blood flow, partial oxygen

  13. Energy metabolism in Desulfovibrio vulgaris Hildenborough: insights from transcriptome analysis

    SciTech Connect

    Pereira, Patricia M.; He, Qiang; Valente, Filipa M.A.; Xavier, Antonio V.; Zhou, Jizhong; Pereira, Ines A.C.; Louro, Ricardo O.

    2007-11-01

    Sulphate-reducing bacteria are important players in the global sulphur and carbon cycles, with considerable economical and ecological impact. However, the process of sulphate respiration is still incompletely understood. Several mechanisms of energy conservation have been proposed, but it is unclear how the different strategies contribute to the overall process. In order to obtain a deeper insight into the energy metabolism of sulphate-reducers whole-genome microarrays were used to compare the transcriptional response of Desulfovibrio vulgaris Hildenborough grown with hydrogen/sulphate, pyruvate/sulphate, pyruvate with limiting sulphate, and lactate/thiosulphate, relative to growth in lactate/sulphate. Growth with hydrogen/sulphate showed the largest number of differentially expressed genes and the largest changes in transcript levels. In this condition the most up-regulated energy metabolism genes were those coding for the periplasmic [NiFeSe]hydrogenase, followed by the Ech hydrogenase. The results also provide evidence for the involvement of formate cycling and the recently proposed ethanol pathway during growth in hydrogen. The pathway involving CO cycling is relevant during growth on lactate and pyruvate, but not during growth in hydrogen as the most down-regulated genes were those coding for the CO-induced hydrogenase. Growth on lactate/thiosulphate reveals a down-regulation of several energymetabolism genes similar to what was observed in the presence of nitrite. This study identifies the role of several proteins involved in the energy metabolism of D. vulgaris and highlights several novel genes related to this process, revealing a more complex bioenergetic metabolism than previously considered.

  14. Ets-1 Regulates Energy Metabolism in Cancer Cells

    PubMed Central

    Verschoor, Meghan L.; Wilson, Leigh A.; Verschoor, Chris P.; Singh, Gurmit

    2010-01-01

    Cancer cells predominantly utilize glycolysis for ATP production even in the presence of abundant oxygen, an environment that would normally result in energy production through oxidative phosphorylation. Although the molecular mechanism for this metabolic switch to aerobic glycolysis has not been fully elucidated, it is likely that mitochondrial damage to the electron transport chain and the resulting increased production of reactive oxygen species are significant driving forces. In this study, we have investigated the role of the transcription factor Ets-1 in the regulation of mitochondrial function and metabolism. Ets-1 was over-expressed using a stably-incorporated tetracycline-inducible expression vector in the ovarian cancer cell line 2008, which does not express detectable basal levels of Ets-1 protein. Microarray analysis of the effects of Ets-1 over-expression in these ovarian cancer cells shows that Ets-1 up-regulates key enzymes involved in glycolysis and associated feeder pathways, fatty acid metabolism, and antioxidant defense. In contrast, Ets-1 down-regulates genes involved in the citric acid cycle, electron transport chain, and mitochondrial proteins. At the functional level, we have found that Ets-1 expression is directly correlated with cellular oxygen consumption whereby increased expression causes decreased oxygen consumption. Ets-1 over-expression also caused increased sensitivity to glycolytic inhibitors, as well as growth inhibition in a glucose-depleted culture environment. Collectively our findings demonstrate that Ets-1 is involved in the regulation of cellular metabolism and response to oxidative stress in ovarian cancer cells. PMID:21042593

  15. Endocrine regulation of energy metabolism by the skeleton

    PubMed Central

    Lee, Na Kyung; Sowa, Hideaki; Hinoi, Eiichi; Ferron, Mathieu; Ahn, Jong Deok; Confavreux, Cyrille; Dacquin, Romain; Mee, Patrick J.; McKee, Marc D.; Jung, Dae Young; Zhang, Zhiyou; Kim, Jason K.; Mauvais-Jarvis, Franck; Ducy, Patricia; Karsenty, Gerard

    2007-01-01

    SUMMARY The regulation of bone remodeling by an adipocyte-derived hormone implies that bone may exert a feedback control of energy homeostasis. To test this hypothesis we looked for genes expressed in osteoblasts, encoding signaling molecules and affecting energy metabolism. We show here that mice lacking the protein tyrosine phosphatase OST-PTP are hypoglycemic and protected from obesity and glucose intolerance because of an increase in ?-cell proliferation, insulin secretion and insulin sensitivity. In contrast, mice lacking the osteoblast-secreted molecule osteocalcin display decreased ?-cell proliferation, glucose intolerance and insulin resistance. Removing one Osteocalcin allele from OST-PTP-deficient mice corrects their metabolic phenotype. Ex vivo, osteocalcin can stimulate CyclinD1 and Insulin expression in ?-cells and Adiponectin, an insulin-sensitizing adipokine, in adipocytes; in vivo osteocalcin can improve glucose tolerance. By revealing that the skeleton exerts an endocrine regulation of sugar homeostasis this study expands the biological importance of this organ and our understanding of energy metabolism. PMID:17693256

  16. Energy recovery from the effluent of plants anaerobically digesting urban solid waste

    NASA Astrophysics Data System (ADS)

    1983-03-01

    The parameters of concentration, time, temperature, and pH to find optimum conditions for enzymatically converting unreacted cellulose in the effluent of an anaerobic digester to glucose for ultimate conversion to methane, and then to project the economics to a 100 tons per day plant was studied. The amount of cellulose hydrolysis for enzyme concentrations from 5 to 1000 CIU/gram of substrate using either filter paper or anaerobically digested municipal solid waste (MSW) reacted over periods of time of from 0 to 72 hours is illustrated. The feasibility of recycling enzymes by ultrafilter capture was studied and it is shown that the recovered enzyme is not denatured by any of several possible enzyme loss mechanisms chemical, physical, or biological. Although rather stable enzyme substrate complexes seem to be formed, various techniques permit a 55% enzyme recovery. Posttreatment of digested MSW by cellulase enzymes produces nearly a threefold increase in biomethanation. The value of the additional methane produced in the process is not sufficient to support the cost of enzymes.

  17. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM AN ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY

    EPA Science Inventory

    The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. he fuel cell is being used for this application becaus...

  18. CHAPTER TWO Vibrio fischeri Metabolism

    E-print Network

    McFall-Ngai, Margaret

    . fischeri Metabolic Pathways are Used in the Host? 49 4.1 Aerobic respiration 49 4.2 Anaerobic respiration: Fur and H-NOX 55 5.3 Anaerobic respiration: FNR 56 5.4 Acetate metabolism: LitR 57 5.5 Summary 57 6

  19. [Modifications in myocardial energy metabolism in diabetic patients

    NASA Technical Reports Server (NTRS)

    Grynberg, A.

    2001-01-01

    The capacity of cardiac myocyte to regulate ATP production to face any change in energy demand is a major determinant of cardiac function. Because FA is the main heart fuel (although the most expensive one in oxygen, and prompt to induce deleterious effects), this process is based on a balanced fatty acid (FA) metabolism. Several pathological situations are associated with an accumulation of FA or derivatives, or with an excessive b-oxidation. The diabetic cardiomyocyte is characterised by an over consumption of FA. The control of the FA/glucose balance clearly appears as a new strategy for cytoprotection, particularly in diabetes and requires a reduced FA contribution to ATP production. Cardiac myocytes can control FA mitochondrial entry, but display weak ability to control FA uptake, thus the fate of non beta-oxidized FA appear as a new impairment for the cell. Both the trigger and the regulation of cardiac contraction result from membrane activity, and the other major FA function in the myocardium is their role in membrane homeostasis, through the phospholipid synthesis and remodeling pathways. Sudden death, hypercatecholaminemia, diabetes and heart failure have been associated with an altered PUFA content in cardiac membranes. Experimental data suggest that the 2 metabolic pathways involved in membrane homeostasis may represent therapeutic targets for cytoprotection. The drugs that increase cardiac phospholipid turnover (trimetazidine, ranolazine,...) display anti-ischemic non hemodynamic effect. This effect is based on a redirection of FA utilization towards phospholipid synthesis, which decrease their availability for energy production. A nutritional approach gave also promising results. Besides its anti-arrhythmic effect, the dietary docosahexaenoic acid is able to reduce FA energy consumption and hence oxygen demand. The cardiac metabolic pathways involving FA should be considered as a whole, precariously balanced. The diabetic heart being characterised by a different metabolic "status" with similarities to that of myocardium in coronary disease. Diabetes and other chronic cardiac diseases share common FA metabolism disorders leading to an altered energy balance, a decrease in long chain polyunsaturated Fas, and altered FA profiles in cardiac membranes. These disturbances, however, do not represent independent therapeutic targets, and should be considered as a whole.

  20. Organ-specific analysis of the anaerobic primary metabolism in rice and wheat seedlings. I: Dark ethanol production is dominated by the shoots.

    PubMed

    Mustroph, Angelika; Boamfa, Elena I; Laarhoven, Lucas J J; Harren, Frans J M; Albrecht, Gerd; Grimm, Bernhard

    2006-12-01

    During anaerobiosis in darkness the main route for ATP production in plants is through glycolysis in combination with fermentation. We compared the organ-specific anaerobic fermentation of flooding-tolerant rice (Oryza sativa) and sensitive wheat (Triticum aestivum) seedlings. A sensitive laser-based photoacoustic trace gas detection system was used to monitor emission of ethanol and acetaldehyde by roots and shoots of intact seedlings. Dark-incubated rice seedlings released 3 times more acetaldehyde and 14 times more ethanol than wheat seedlings during anaerobiosis. Ninety percent of acetaldehyde originated from shoots of both species. In comparison to wheat shoots, the high ethanol production of rice shoots correlated with larger amounts of soluble carbohydrates, and higher activities of fermentative enzymes. After 24 h of anaerobiosis in darkness rice shoots still contained 30% of aerated ATP level, which enabled seedlings to survive this period. In contrast, ATP content declined almost to zero in wheat shoots and roots, which were irreversibly damaged after a 24-h anaerobic period. When plants were anaerobically and dark incubated for 4 h and subsequently transferred back to aeration, shoots showed a transient peak of acetaldehyde release indicating prompt re-oxidation of ethanol. Post-anoxic acetaldehyde production was lower in rice seedlings than in wheat. This observation accounts for a more effective acetaldehyde detoxification system in rice. Compared to wheat the greater tolerance of rice seedlings to transient anaerobic periods is explained by a faster fermentation rate of their shoots allowing a sufficient ATP production and an efficient suppression of toxic acetaldehyde formation in the early re-aeration period. PMID:16845530

  1. Legal pre-event nutritional supplements to assist energy metabolism.

    PubMed

    Spriet, Lawrence L; Perry, Christopher G R; Talanian, Jason L

    2008-01-01

    Physical training and proper nutrition are paramount for success in sport. A key tissue is skeletal muscle, as the metabolic pathways that produce energy or ATP allow the muscles to complete the many activities critical to success in sport. The energy-producing pathways must rapidly respond to the need for ATP during sport and produce energy at a faster rate or for a longer duration through training and proper nutrition which should translate into improved performance in sport activities. There is also continual interest in the possibility that nutritional supplements could further improve muscle metabolism and the provision of energy during sport. Most legal sports supplements do not improve performance following oral ingestion. However, three legal supplements that have received significant attention over the years include creatine, carnitine and sodium bicarbonate. The ingestion of large amounts of creatine for 4-6 days increases skeletal muscle creatine and phosphocreatine contents. The majority of the experimental evidence suggests that creatine supplementation can improve short-term exercise performance, especially in sports that require repeated short-term sprints. It may also augment the accretion of skeletal muscle when taken in combination with a resistance-exercise training programme. Supplementary carnitine has been touted to increase the uptake and oxidation of fat in the mitochondria. However, muscle carnitine levels are not augmented following oral carnitine supplementation and the majority of well-controlled studies have reported no effect of carnitine on enhancing fat oxidation, Vo(2max) or prolonged endurance exercise performance. The ingestion of sodium bicarbonate before intense exercise decreases the blood [H+] to potentially assist the efflux of H+ from the muscle and temper the metabolic acidosis associated with intense exercise. Many studies have reported performance increases in laboratory-based cycling tests and simulated running races in the field following sodium bicarbonate ingestion where the need for ATP from substrate phosphorylation is high. However, other studies have reported no benefit and the incidence of negative side effects is high. PMID:18384281

  2. Polyphosphate - an ancient energy source and active metabolic regulator

    PubMed Central

    2011-01-01

    There are a several molecules on Earth that effectively store energy within their covalent bonds, and one of these energy-rich molecules is polyphosphate. In microbial cells, polyphosphate granules are synthesised for both energy and phosphate storage and are degraded to produce nucleotide triphosphate or phosphate. Energy released from these energetic carriers is used by the cell for production of all vital molecules such as amino acids, nucleobases, sugars and lipids. Polyphosphate chains directly regulate some processes in the cell and are used as phosphate donors in gene regulation. These two processes, energetic metabolism and regulation, are orchestrated by polyphosphate kinases. Polyphosphate kinases (PPKs) can currently be categorized into three groups (PPK1, PPK2 and PPK3) according their functionality; they can also be divided into three groups according their homology (EcPPK1, PaPPK2 and ScVTC). This review discusses historical information, similarities and differences, biochemical characteristics, roles in stress response regulation and possible applications in the biotechnology industry of these enzymes. At the end of the review, a hypothesis is discussed in view of synthetic biology applications that states polyphosphate and calcium-rich organelles have endosymbiotic origins from ancient protocells that metabolized polyphosphate. PMID:21816086

  3. Dual energy metabolism-dependent effect of Ureaplasma urealyticum infection on sperm activity.

    PubMed

    Reichart, M; Levi, H; Kahane, I; Bartoov, B

    2001-01-01

    Genital Ureaplasma urealyticum infection is considered a sexually transmitted infection. It has long been debated whether the presence of U. urealyticum in semen may be a possible cause of infertility. Long-term incubation (4 hours or overnight) of sperm cells with U. urealyticum in vitro resulted in a significant inhibition of sperm motility and membrane alteration whereas a short incubation (45 minutes) of sperm cells with ureaplasmas resulted in an acceleration of sperm velocity. The aim of this study was to understand these contradictory reports of U. urealyticum infection on sperm motility. Spermatozoa from fresh ejaculates of normozoospermic semen of men who were referred to the university Male Fertility Laboratory for semen analysis, with no history of genital tract infection, and from normal Assaf breed rams were infected in vitro with U. urealyticum serotype 8, at different pHs and O2 concentrations. Sperm viability and motility and changes in extracellular pH were evaluated. A significant (16%-43%) increase in sperm activity was observed upon infection at alkaline pH (7.8) under aerobic or hypoxic conditions, and a 58% increase was observed under anaerobic conditions and pH 7.2. When the infection was conducted under aerobic conditions and acidic pH (6.3), or under hypoxic conditions at neutral pH (7.2), an 8%-25% inhibition of sperm activity was observed. These results indicate that when sperm activity depends on mitochondrial oxidative phosphorylation, usually at low pHs, U. urealyticum competes with mitochondrial energy production and therefore reduces sperm motility and viability. However, when sperm energy metabolism depends on glycolysis, usually at higher pHs, U. urealyticum stimulates glycolysis and sperm activity. PMID:11330640

  4. Experimental ocean acidification alters the allocation of metabolic energy

    PubMed Central

    Pan, T.-C. Francis; Applebaum, Scott L.; Manahan, Donal T.

    2015-01-01

    Energy is required to maintain physiological homeostasis in response to environmental change. Although responses to environmental stressors frequently are assumed to involve high metabolic costs, the biochemical bases of actual energy demands are rarely quantified. We studied the impact of a near-future scenario of ocean acidification [800 µatm partial pressure of CO2 (pCO2)] during the development and growth of an important model organism in developmental and environmental biology, the sea urchin Strongylocentrotus purpuratus. Size, metabolic rate, biochemical content, and gene expression were not different in larvae growing under control and seawater acidification treatments. Measurements limited to those levels of biological analysis did not reveal the biochemical mechanisms of response to ocean acidification that occurred at the cellular level. In vivo rates of protein synthesis and ion transport increased ?50% under acidification. Importantly, the in vivo physiological increases in ion transport were not predicted from total enzyme activity or gene expression. Under acidification, the increased rates of protein synthesis and ion transport that were sustained in growing larvae collectively accounted for the majority of available ATP (84%). In contrast, embryos and prefeeding and unfed larvae in control treatments allocated on average only 40% of ATP to these same two processes. Understanding the biochemical strategies for accommodating increases in metabolic energy demand and their biological limitations can serve as a quantitative basis for assessing sublethal effects of global change. Variation in the ability to allocate ATP differentially among essential functions may be a key basis of resilience to ocean acidification and other compounding environmental stressors. PMID:25825763

  5. Experimental ocean acidification alters the allocation of metabolic energy.

    PubMed

    Pan, T-C Francis; Applebaum, Scott L; Manahan, Donal T

    2015-04-14

    Energy is required to maintain physiological homeostasis in response to environmental change. Although responses to environmental stressors frequently are assumed to involve high metabolic costs, the biochemical bases of actual energy demands are rarely quantified. We studied the impact of a near-future scenario of ocean acidification [800 µatm partial pressure of CO2 (pCO2)] during the development and growth of an important model organism in developmental and environmental biology, the sea urchin Strongylocentrotus purpuratus. Size, metabolic rate, biochemical content, and gene expression were not different in larvae growing under control and seawater acidification treatments. Measurements limited to those levels of biological analysis did not reveal the biochemical mechanisms of response to ocean acidification that occurred at the cellular level. In vivo rates of protein synthesis and ion transport increased ?50% under acidification. Importantly, the in vivo physiological increases in ion transport were not predicted from total enzyme activity or gene expression. Under acidification, the increased rates of protein synthesis and ion transport that were sustained in growing larvae collectively accounted for the majority of available ATP (84%). In contrast, embryos and prefeeding and unfed larvae in control treatments allocated on average only 40% of ATP to these same two processes. Understanding the biochemical strategies for accommodating increases in metabolic energy demand and their biological limitations can serve as a quantitative basis for assessing sublethal effects of global change. Variation in the ability to allocate ATP differentially among essential functions may be a key basis of resilience to ocean acidification and other compounding environmental stressors. PMID:25825763

  6. Anaerobic Nitrate-Dependent Metal Bio-Oxidation

    NASA Astrophysics Data System (ADS)

    Weber, K.; Knox, T.; Achenbach, L. A.; Coates, J. D.

    2007-12-01

    Direct biological oxidation of reduced metals (Fe(II) and U(IV)) coupled to nitrate reduction at circumneutral pH under anaerobic conditions has been recognized in several environments as well as pure culture. Several phylogentically diverse mesophilic bacteria have been described as capable of anaerobic, nitrate-dependent Fe(II) oxidation (NFOx). Our recent identification of a freshwater mesophilic, lithoautotroph, Ferrutens nitratireducens strain 2002, capable of growth through NFOx presents an opportunity to further study metal bio- oxidation. Continuing physiological studies revealed that in addition to Fe(II) oxidation, strain 2002 is capable of oxidizing U(IV) (4 ?M) in washed cell suspensions with nitrate serving as the electron acceptor. Pasteurized cultures exhibited abiotic oxidation of 2 ?M U(IV). Under growth conditions, strain 2002 catalyzed the oxidation of 12 ?M U(IV) within a two week period. Cultures amended with sodium azide, an electron transport inhibitor, demonstrated limited oxidation (7 ?M) similar to pasteurized cultures, supporting the direct role of electron transport in U(IV) bio-oxidation. The oxidation of U(IV) coupled denitrification at circumneutral pH would yield enough energy to support anaerobic microbial growth (?G°'= -460.36 kJ/mole). It is currently unknown whether or not strain 2002 can couple this metabolism to growth. The growth of F. nitratireducens strain 2002 utilizing Fe(II) as the sole electron donor was previously demonstrated. The amount of U(IV) (~12 ?M) that strain 2002 oxidized under similar autotrophic growth conditions yields 0.0019 kJ, enough energy for the generation of ATP (5.3 x 10-20 kJ ATP-1), but not enough energy for cell replication as calculated for nitrate-dependent Fe(II) oxidizing conditions (0.096 kJ) assuming a similar metabolism. In addition to F. nitratireducens strain 2002, a nitrate-dependent Fe(II) oxidizing bacterium isolated from U contaminated groundwater, Diaphorobacter sp. strain TPSY, was also capable of nitrate- dependent U(IV) oxidation (8 ?M over 24 hours, pseudo first order rate constant of 0.12 ± 0.02 hr-1) in washed cell suspensions. Further biochemical investigation of nitrate-dependent U(IV) oxidation in strain TPSY revealed the expression of several putative high molecular weight proteins specific to this metabolism. Together with the previously described metabolic ability of Geobacter metallireducens (Finneran et al. 2002) and Thiobacillus denitrificans (Beller 2005), these data indicate that anaerobic, metal oxidation may be a ubiquitous microbial metabolism.

  7. Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

    PubMed Central

    Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar; Smith, Jessica A.; Bain, Timothy S.; Lovley, Derek R.

    2013-01-01

    Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (<0.5 ?M) of phenol accumulated in cultures of Geobacter metallireducens anaerobically oxidizing benzene to carbon dioxide with the reduction of Fe(III). Phenol was not detected in cell-free controls or in Fe(II)- and benzene-containing cultures of Geobacter sulfurreducens, a Geobacter species that cannot metabolize benzene. The phenol produced in G. metallireducens cultures was labeled with 18O during growth in H218O, as expected for anaerobic conversion of benzene to phenol. Analysis of whole-genome gene expression patterns indicated that genes for phenol metabolism were upregulated during growth on benzene but that genes for benzoate or toluene metabolism were not, further suggesting that phenol was an intermediate in benzene metabolism. Deletion of the genes for PpsA or PpcB, subunits of two enzymes specifically required for the metabolism of phenol, removed the capacity for benzene metabolism. These results demonstrate that benzene hydroxylation to phenol is an alternative to carboxylation for anaerobic benzene activation and suggest that this may be an important metabolic route for benzene removal in petroleum-contaminated groundwaters, in which Geobacter species are considered to play an important role in anaerobic benzene degradation. PMID:24096430

  8. [Lipids composition and speed of energy metabolism in gastropods].

    PubMed

    Arakelova, E S

    2008-01-01

    Lipid composition of digestive gland and pedal muscle of two northern freshwater pulmonate snails Lymnaea stagnalis and Lymnaea ovata and three marine prosobranch gastropods Littorina obtusata, Littorina littorea, Buccinum undatum from the White Sea was studied. The species differ in ecology, particularly in trophic nabits and motor activity. The content of triacilglycerides both in digestive gland and pedal was higher in littoral dwellers Littorina the activity of which depends on the tide level. The phospholipids content in digestive gland does not differ in quantity in all cases and does not relate to type of feeding or resource quality. In a pedal muscle of marine species the quantity of common phospholipids is higher in comparison with the freshwater ones. The amount of total phospholipids in pedal muscle correlates with mass of metabolic inert formation which constitutes a part of whole mass of snails. The presence of massive shell enhances demands in energy needed for supporting movement and activity. Because the intensity of energy metabolism is related to quantity of total phospholipids, mitochondria and activity of their oxidizing ferments, the presence of thick shell in marine snails together with motor activity costs more in terms of energy than in freshwater snails with thin shell. This hypothesis is supported by the higher specific rate of oxygen consumption in marine snails than in freshwaters. PMID:19140337

  9. EBPR using crude glycerol: assessing process resiliency and exploring metabolic anomalies.

    PubMed

    Coats, Erik R; Dobroth, Zachary T; Brinkman, Cynthia K

    2015-01-01

    Enhanced biological phosphorus removal (EBPR) is predicated on exposing bacteria to cyclical anaerobic/aerobic environments while providing volatile fatty acids (VFAs). Combined, this environment enriches for phosphorus accumulating organisms (PAOs) and induces metabolisms to ensure excess phosphorus removal. Crude glycerol (CG), a byproduct of biodiesel manufacturing, is an alternate waste stream that could be substituted to achieve excess phosphorus removal; research into the use of CG yielded unexpected findings. While CG was an excellent substrate to accomplish and/or help achieve excess phosphorus removal, CG-fed bacteria did not consistently exhibit theoretical EBPR metabolisms. Specifically, anaerobic phosphorus release was not required for successful EBPR; however, carbon cycling patterns were consistent with theory. Analysis of results suggests that PAOs will first leverage carbon to generate energy anaerobically; only as needed will the bacteria utilize polyphosphate reserves anaerobically. Results also demonstrated that excess phosphorus removal can be achieved with a small fraction of PAOs. PMID:25630129

  10. Biology, ecology, and biotechnological applications of anaerobic bacteria adapted to environmental stresses in temperature, pH, salinity, or substrates.

    PubMed Central

    Lowe, S E; Jain, M K; Zeikus, J G

    1993-01-01

    Anaerobic bacteria include diverse species that can grow at environmental extremes of temperature, pH, salinity, substrate toxicity, or available free energy. The first evolved archaebacterial and eubacterial species appear to have been anaerobes adapted to high temperatures. Thermoanaerobes and their stable enzymes have served as model systems for basic and applied studies of microbial cellulose and starch degradation, methanogenesis, ethanologenesis, acetogenesis, autotrophic CO2 fixation, saccharidases, hydrogenases, and alcohol dehydrogenases. Anaerobes, unlike aerobes, appear to have evolved more energy-conserving mechanisms for physiological adaptation to environmental stresses such as novel enzyme activities and stabilities and novel membrane lipid compositions and functions. Anaerobic syntrophs do not have similar aerobic bacterial counterparts. The metabolic end products of syntrophs are potent thermodynamic inhibitors of energy conservation mechanisms, and they require coordinated consumption by a second partner organism for species growth. Anaerobes adapted to environmental stresses and their enzymes have biotechnological applications in organic waste treatment systems and chemical and fuel production systems based on biomass-derived substrates or syngas. These kinds of anaerobes have only recently been examined by biologists, and considerably more study is required before they are fully appreciated by science and technology. Images PMID:8336675

  11. Metabolic adaptation for low energy throughput in orangutans

    PubMed Central

    Pontzer, Herman; Raichlen, David A.; Shumaker, Robert W.; Ocobock, Cara; Wich, Serge A.

    2010-01-01

    Energy is the fundamental currency of life—needed for growth, repair, and reproduction—but little is known about the metabolic physiology and evolved energy use strategies of the great apes, our closest evolutionary relatives. Here we report daily energy use in free-living orangutans (Pongo spp.) and test whether observed differences in energy expenditure among orangutans, humans, and other mammals reflect known differences in life history. Using the doubly labeled water method, we measured daily energy expenditure (kCal/d) in orangutans living in a large indoor/outdoor habitat at the Great Ape Trust. Despite activity levels similar to orangutans in the wild, Great Ape Trust orangutans used less energy, relative to body mass, than nearly any eutherian mammal ever measured, including sedentary humans. Such an extremely low rate of energy use has not been observed previously in primates, but is consistent with the slow growth and low rate of reproduction in orangutans, and may be an evolutionary response to severe food shortages in their native Southeast Asian rainforests. These results hold important implications for the management of orangutan populations in captivity and in the wild, and underscore the flexibility and interdependence of physiological, behavioral, and life history strategies in the evolution of apes and humans. PMID:20679208

  12. Cell energy budget platform for assessment of cell metabolism.

    PubMed

    Papkovsky, Dmitri B; Zhdanov, Alexander V

    2015-01-01

    Changes in bioenergetic parameters report on metabolic rearrangement, dysfunction of major pathways, and regulatory processes within the cell, adaptation to energy stress, or new physiological condition. A combined measurement of oxidative phosphorylation, glycolytic flux, the Krebs cycle activity, ATP levels, and total biomass allows detailed metabolic assessment. We describe a simple methodology for high-throughput multiparametric assessment of cell bioenergetics, called cell energy budget (CEB) platform, and demonstrate its practical use with cell models. The CEB relies on a standard multi-label reader with time-resolved fluorescence capabilities, the lanthanide probe pH-Xtra™ to measure extracellular acidification (ECA) associated with lactate (L-ECA) and combined lactate/CO2 (T-ECA) extrusion, the phosphorescent probe MitoXpress®-Xtra to measure oxygen consumption rate (OCR), the bioluminescent total ATP assay, and absorbance-based total protein assay. This approach can be further extended with the measurement of other cellular parameters, such as NAD(P)H, Ca(2+), mitochondrial pH, membrane potential, and redox state, using the corresponding fluorescent or luminescent probes. PMID:25634285

  13. Intracellular flux of glucose metabolism in streptococcal cells by simultaneous monitoring of fluorescence dependent on reduced nicotinamide adenine nucleotide and acid excretion under strictly anaerobic conditions.

    PubMed

    Iwami, Y; Yamada, T

    1999-08-01

    Reduced nicotinamide adenine nucleotide (NADH)-dependent fluorescence and acid excretion during glucose pulse to washed Streptococcus mutans cells were monitored simultaneously at pH 7.0 with a fluorescence spectrophotometer and a pH-stat. Acid excretion started with addition of glucose. At the same time, the fluorescence dropped quickly to a minimum level and increased to a plateau level, suggesting that pyruvate metabolism started immediately after addition of glucose, then the rate of the pyruvate metabolism became almost equal to the rate of glycolysis. When the acid excretion stopped, the fluorescence increased rapidly from the plateau to the maximum level, suggesting that the pyruvate metabolism stopped first, and then began to decrease to the original level. The system used in this study for simultaneously monitoring the level of NADH and acid excretion gives us a crucial tool to clarify a biochemical mechanism of the control of sugar metabolism by streptococci. PMID:10551165

  14. Hemicellulose conversion by anaerobic digestion

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Christopher, R.W.

    1982-01-01

    The digestibility of an aquatic biomass (water hyacinth), a land-based biomass (Coastal Bermuda grass), and a biomass-waste blend (a mixture of hyacinth, grass, MSW, and sludge) under various digestion conditions was studied. Anaerobic digestion of hemicellulose consists of the steps of enzymatic hydrolysis of hemicellulose to glucans, mannans, galactans, xylans, and arabans, and then to simple hexose and pentose sugars; production of C/sub 2/ and higher fatty acids from the simple sugars; conversion of higher fatty acids to acetate; and finally, production of methane and CO/sub 2/ from acetate, and CO/sub 2/ and hydrogen. The conversion of hemicellulose was higher under mesophilic conditions than those of cellulose or protein for all biomass test feeds, probably because the hemicellulose structure was more vulnerable to enzymatic attack than that of the lignocellulosic component. Cellulose conversion efficiencies at the mesophilic and thermophilic temperatures were about the same. However, hemicellulose was converted at a much lower efficiency than cellulose during thermophilic digestion - a situation that was the reverse of that observed at the mesophilic temperature. Cellulose was utilized in preference to hemicellulose during mesophilic digestion of nitrogen-supplemented Bermuda grass. It was speculated that Bermuda grass cellulose was converted at a higher efficiency than hemicellulose in the presence of external nitrogen because the metabolism of the breakdown product (glucose) of cellulose requires the least investment of enzymes and energy.

  15. Occupation-dependent access to metabolic energy in Fröhlich systems.

    PubMed

    Srobár, Fedor

    2009-01-01

    Fröhlich systems model ensembles of electromagnetic-radiation-emitting molecular oscillators residing inside biological cells. The core piece of this theory are rate equations for the quantum-mechanical occupation numbers of the collective oscillation modes that take into account the flow of metabolic energy through the ensemble. In continuation of prior study of feedback patterns implicit in this model, oriented multigraphs representation is used to investigate the case when the pumping source-in analogy with the effect of spectral hole burning in injection lasers-exhibits depletion phenomena dependent on occupation numbers and the eigenfrequencies of the modes. As a result, in comparison with the case when all modes have equal access to pumping source, the onset of energy condensation in the fundamental mode is shifted to higher pumping levels and new feedback loops appear in the representative diagram. The modified theory provides a more realistic description of electromagnetic emission in biological cells. PMID:19811401

  16. Regulation of energy metabolism by the skeleton: osteocalcin and beyond.

    PubMed

    Ferron, Mathieu; Lacombe, Julie

    2014-11-01

    The skeleton has recently emerged as an endocrine organ implicated in the regulation of glucose and energy metabolism. This function of bone is mediated, at least in part, by osteocalcin, an osteoblast-derived protein acting as a hormone stimulating insulin sensitivity, insulin secretion and energy expenditure. Osteocalcin secretion and bioactivity is in turn regulated by several hormonal cues including insulin, leptin, the sympathetic nervous system and glucocorticoids. Recent findings support the notion that osteocalcin functions and regulations are conserved between mice and humans. Moreover, studies in mice suggest that osteocalcin could represent a viable therapeutic approach for the treatment of obesity and insulin resistance. In this review, we summarize the current knowledge on osteocalcin functions, its various modes of action and the mechanisms implicated in the control of this hormone. PMID:24893146

  17. Anaerobic Thermophiles

    PubMed Central

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely made this area of investigation more exciting. Particularly fascinating are their structural and physiological features allowing them to withstand extremely selective environmental conditions. These properties are often due to specific biomolecules (DNA, lipids, enzymes, osmolites, etc.) that have been studied for years as novel sources for biotechnological applications. In some cases (DNA-polymerase, thermostable enzymes), the search and applications successful exceeded preliminary expectations, but certainly further exploitations are still needed. PMID:25370030

  18. Adaptive Evolution of Mitochondrial Energy Metabolism Genes Associated with Increased Energy Demand in Flying Insects

    PubMed Central

    Yang, Yunxia; Xu, Shixia; Xu, Junxiao; Guo, Yan; Yang, Guang

    2014-01-01

    Insects are unique among invertebrates for their ability to fly, which raises intriguing questions about how energy metabolism in insects evolved and changed along with flight. Although physiological studies indicated that energy consumption differs between flying and non-flying insects, the evolution of molecular energy metabolism mechanisms in insects remains largely unexplored. Considering that about 95% of adenosine triphosphate (ATP) is supplied by mitochondria via oxidative phosphorylation, we examined 13 mitochondrial protein-encoding genes to test whether adaptive evolution of energy metabolism-related genes occurred in insects. The analyses demonstrated that mitochondrial DNA protein-encoding genes are subject to positive selection from the last common ancestor of Pterygota, which evolved primitive flight ability. Positive selection was also found in insects with flight ability, whereas no significant sign of selection was found in flightless insects where the wings had degenerated. In addition, significant positive selection was also identified in the last common ancestor of Neoptera, which changed its flight mode from direct to indirect. Interestingly, detection of more positively selected genes in indirect flight rather than direct flight insects suggested a stronger selective pressure in insects having higher energy consumption. In conclusion, mitochondrial protein-encoding genes involved in energy metabolism were targets of adaptive evolution in response to increased energy demands that arose during the evolution of flight ability in insects. PMID:24918926

  19. Novel metabolic roles of L-arginine in body energy metabolism and possible clinical applications.

    PubMed

    Hristina, K; Langerholc, T; Trapecar, M

    2014-01-01

    Although the body can synthesize L-arginine, exogenous supplementation may be sometimes necessary, especially in particular conditions which results in depleted endogenous source. Among diseases and states when exogenous supplementation may be necessary are: burns, severe wounds, infections, insufficient circulation, intensive physical activity or sterility. In recent time, the attention was paid to the use of L-arginine supplementation by athletes during intensive sport activity, to enhance tissue growth and general performance, to potentiate the ergogenic potential and muscle tolerance to high intensive work and gas exchange threshold, to decrease ammonia liberation and recovery performance period and to improve wound healing. High-intensity exercise produces transient hyperammoniemia, presumably due to AMP catabolism. Catabolic pathways of AMP may involve its deamination or dephosphorylation, mainly in order to compensate fall in adenylate enrgy charge (AEC), due to AMP rise. The enzymes of purine metabolism have been documented to be particularly sensitive to the effect of dietary L-arginine supplementation. L-arginine supplementation leads to redirection of AMP deamination on account of increased AMP dephosphorylation and subsequent adenosine production and may increase ATP regeneration via activation of AMP kinase (AMPK) pathway. The central role of AMPK in regulating cellular ATP regeneration, makes this enzyme as a central control point in energy homeostasis. The effects of L-arginine supplementation on energy expenditure were successful independently of age or previous disease, in young sport active, elderly, older population and patients with angina pectoris. PMID:24522477

  20. Actions of juglone on energy metabolism in the rat liver.

    PubMed

    Saling, Simoni Cristina; Comar, Jurandir Fernando; Mito, Márcio Shigueaki; Peralta, Rosane Marina; Bracht, Adelar

    2011-12-15

    Juglone is a phenolic compound used in popular medicine as a phytotherapic to treat inflammatory and infectious diseases. However, it also acts as an uncoupler of oxidative phosphorylation in isolated liver mitochondria and, thus, may interfere with the hepatic energy metabolism. The purpose of this work was to evaluate the effect of juglone on several metabolic parameters in the isolated perfused rat liver. Juglone, in the concentration range of 5 to 50?M, stimulated glycogenolysis, glycolysis and oxygen uptake. Gluconeogenesis from both lactate and alanine was inhibited with half-maximal effects at the concentrations of 14.9 and 15.7?M, respectively. The overall alanine transformation was increased by juglone, as indicated by the stimulated release of ammonia, urea, l-glutamate, lactate and pyruvate. A great increase (9-fold) in the tissue content of ?-ketoglutarate was found, without a similar change in the l-glutamate content. The tissue contents of ATP were decreased, but those of ADP and AMP were increased. Experiments with isolated mitochondria fully confirmed previous notions about the uncoupling action of juglone. It can be concluded that juglone is active on metabolism at relatively low concentrations. In this particular it resembles more closely the classical uncoupler 2,4-dinitrophenol. Ingestion of high doses of juglone, thus, presents the same risks as the ingestion of 2,4-dinitrophenol which comprise excessive compromising of ATP production, hyperthermia and even death. Low doses, i.e., moderate consumption of natural products containing juglone, however, could be beneficial to health if one considers recent reports about the consequences of chronic mild uncoupling. PMID:21945490

  1. The metabolic energy cost of action potential velocity

    NASA Astrophysics Data System (ADS)

    Crotty, Patrick; Sangrey, Thomas; Levy, William

    2006-03-01

    Voltage changes in neurons and other active cells are caused by the passage of ions across the cell membrane. These ionic currents depend on the transmembrane ion concentration gradients, which in unmyelinated axons are maintained during rest and restored after electrical activity by an ATPase sodium-potassium exchanger in the membrane. The amount of ATP consumed by this exchanger can be taken as the metabolic energy cost of any electrical activity in the axon. We use this measure, along with biophysical models of voltage-gated sodium and potassium ion channels, to quantify the energy cost of action potentials propagating in squid giant axons. We find that the energy of an action potential can be naturally divided into three separate components associated with different aspects of the action potential. We calculate these energy components as functions of the ion channel densities and axon diameters and find that the component associated with the rising phase and velocity of the action potential achieves a minimum near the biological values of these parameters. This result, which is robust with respect to other parameters such as temperature, suggests that evolution has optimized the axon for the energy of the action potential wavefront.

  2. Benzoyl-coenzyme A reductase (dearomatizing), a key enzyme of anaerobic aromatic metabolism. ATP dependence of the reaction, purification and some properties of the enzyme from Thauera aromatica strain K172.

    PubMed

    Boll, M; Fuchs, G

    1995-12-15

    Anoxic metabolism of many aromatic compounds proceeds via the common intermediate benzoyl-CoA. Benzoyl-CoA is dearomatized by benzoyl-CoA reductase (dearomatizing) in a two-electron reduction step, possibly yielding cyclohex-1,5-diene-1-carboxyl-CoA. This process has to overcome a high activation energy and is considered a biological Birch reduction. The central, aromatic-ring-reducing enzyme was investigated for the first time in the denitrifying bacterium Thauera aromatica strain K172. A spectrophotometric assay was developed which was strictly dependent on MgATP, both with cell extract and with purified enzyme. The oxygen-sensitive new enzyme was purified 35-fold with 20% yield under anaerobic conditions in the presence of 0.25 mM dithionite. It had a native molecular mass of approximately 170 kDa and consisted of four subunits a,b,c,d of 48, 45, 38 and 32 kDa. The oligomer composition of the protein most likely is abcd. The ultraviolet/visible spectrum of the protein as isolated, but without dithionite, was characteristic for an iron-sulfur protein with an absorption maximum at 279 nm and a broad shoulder at 390 nm. The estimated molar absorption coefficient at 390 nm was 35,000 M-1 cm-1. Reduction of the enzyme by dithionite resulted in a decrease of absorbance at 390 nm, and the colour turned from greenish-brown to red-brown. The enzyme contained 10.8 +/- 1.5 mol Fe and 10.5 +/- 1.5 mol acid-labile sulfur/mol. Besides zinc (0.5 mol/mol protein) no other metals nor selenium could be detected in significant amounts. The enzyme preparation contained a flavin or flavin-like compound; the estimated content was 0.3 mol/mol enzyme. The enzyme reaction required MgATP and a strong reductant such as Ti(III). The reaction catalyzed is: benzoyl-CoA + 2 Ti(III) + n ATP-->non-aromatic acyl-CoA + 2 Ti(IV) + n ADP + n Pi. The estimated number n of ATP molecules hydrolyzed/two electrons transferred in benzoyl-CoA reduction is 2-4. In the absence of benzoyl-CoA the enzyme exhibited oxygen-sensitive ATPase activity. The enzyme was specific for Mg(2+)-ATP, other nucleoside triphosphates being inactive (< 1%). Mg2+ could be substituted to some extent by Mn2+, Fe2+ and less efficiently by Co2+. Benzoate was not reduced, whereas some fluoro, hydroxy, amino and methyl analogues of the activated benzoic acid were reduced, albeit at much lower rate; the products remain to be identified. The specific activity with reduced methyl viologen as the electron donor was 0.55 mumol min-1 mg-1 corresponding to a catalytic number of 1.6 s-1. The apparent Km values under the assay conditions (0.5 mM for both reduced and oxidized methyl viologen) of benzoyl-CoA and ATP were 15 microM and 0.6 mM, respectively. The enzyme was inactivated by ethylene, bipyridyl and, in higher concentrations, by acetylene. Benzoyl-CoA reductase also catalyzed the ATP-dependent two-electron reduction of hydroxylamine (Km 0.15 mM) and azide. Some of the properties of the enzyme are reminiscent of those of nitrogenase which similarly overcomes the high activation energy for dinitrogen reduction by coupling electron transfer to the hydrolysis of ATP. PMID:8575453

  3. Remodeling of Oxidative Energy Metabolism by Galactose Improves Glucose Handling and Metabolic Switching in Human Skeletal Muscle Cells

    PubMed Central

    Kase, Eili Tranheim; Nikoli?, Nataša; Bakke, Siril Skaret; Bogen, Kaja Kamilla; Aas, Vigdis; Thoresen, G. Hege; Rustan, Arild Christian

    2013-01-01

    Cultured human myotubes have a low mitochondrial oxidative potential. This study aims to remodel energy metabolism in myotubes by replacing glucose with galactose during growth and differentiation to ultimately examine the consequences for fatty acid and glucose metabolism. Exposure to galactose showed an increased [14C]oleic acid oxidation, whereas cellular uptake of oleic acid uptake was unchanged. On the other hand, both cellular uptake and oxidation of [14C]glucose increased in myotubes exposed to galactose. In the presence of the mitochondrial uncoupler carbonylcyanide p-trifluormethoxy-phenylhydrazone (FCCP) the reserve capacity for glucose oxidation was increased in cells grown with galactose. Staining and live imaging of the cells showed that myotubes exposed to galactose had a significant increase in mitochondrial and neutral lipid content. Suppressibility of fatty acid oxidation by acute addition of glucose was increased compared to cells grown in presence of glucose. In summary, we show that cells grown in galactose were more oxidative, had increased oxidative capacity and higher mitochondrial content, and showed an increased glucose handling. Interestingly, cells exposed to galactose showed an increased suppressibility of fatty acid metabolism. Thus, galactose improved glucose metabolism and metabolic switching of myotubes, representing a cell model that may be valuable for metabolic studies related to insulin resistance and disorders involving mitochondrial impairments. PMID:23560061

  4. Targeting energy metabolism in brain cancer: review and hypothesis

    Microsoft Academic Search

    Thomas N Seyfried; Purna Mukherjee

    2005-01-01

    Malignant brain tumors are a significant health problem in children and adults and are often unmanageable. As a metabolic disorder involving the dysregulation of glycolysis and respiration, malignant brain cancer is potentially manageable through changes in metabolic environment. A radically different approach to brain cancer management is proposed that combines metabolic control analysis with the evolutionarily conserved capacity of normal

  5. Ecophysiological adaptations of anaerobic bacteria to low pH. [Sarcina ventriculi; Lactobacillus helveticus

    SciTech Connect

    Goodwin, S.D.

    1986-01-01

    The ecological and physiological adaptations of anaerobic bacteria to low pH were investigated in field and laboratory studies. Determinations of hydrogen kinetic parameters demonstrated that overall hydrogen metabolism was inhibited in acid ecosystems. In particular, hydrogen metabolism became progressively uncoupled at low pH. This uncoupling resulted in a slowing of carbon flow during anaerobic digestion and the accumulation of intermediary metabolites. The addition of carbon electron donors to acid bog sediments resulted in the accumulation of hydrogen and a slowing of the overall rates of anaerobic digestion. As an adaptation to low pH, anaerobic bacterial populations shifted from production of acid intermediary metabolites (e.g. acetate and lactate) to the production of neutral intermediary metabolites (e.g. ethanol). This shift was observed both in situ and in pure cultures of hydrolytic strains isolated from bog sediments. Detailed physiological studies of Sarcina ventriculi showed an adaptation to growth at low pH by mechanisms which allowed the continued production of ethanol from glucose and the maintenance of a proton motive force at low cytoplasmic pH values. Further physiological studies Lactobacillus helveticus showed that the accumulation of acidic end-product (lactic acid) strongly influenced cellular electrochemical parameters. Based on the results of computer simulations and laboratory studies of the physiology of the organism in the presence of organic acids, a new model for the passive coupling of energy conservation to the efflux of lactic acid in an electroneutral process is proposed.

  6. Dietary Energy Source in Dairy Cows in Early Lactation: Metabolites and Metabolic Hormones

    Microsoft Academic Search

    Knegsel van A. T. M; H. van den Brand; E. A. M. Graat; J. Dijkstra; R. Jorritsma; M. P. Decuypere; S. Tamminga; B. Kemp

    2007-01-01

    Negative energy balance-related metabolic disorders suggest that the balance between available lipogenic and glucogenic nutrients is important. The objectives of this study were to compare the effects of a glucogenic or a lipogenic diet on liver triacylglycerides (TAG), metabolites, and metabolic hormones in dairy cows in early lactation and to relate metabolite concentrations to the determined energy retention in body

  7. Sustainable organic loading rate and energy recovery potential of mesophilic anaerobic membrane bioreactor for municipal wastewater treatment.

    PubMed

    Wei, Chun-Hai; Harb, Moustapha; Amy, Gary; Hong, Pei-Ying; Leiknes, TorOve

    2014-08-01

    The overall performance of a mesophilic anaerobic membrane bioreactor (AnMBR) for synthetic municipal wastewater treatment was investigated under a range of organic loading rate (OLR). A very steady and high chemical oxygen demand (COD) removal (around 98%) was achieved over a broad range of volumetric OLR of 0.8-10 gCOD/L/d. The sustainable volumetric and sludge OLR satisfying a permeate COD below 50 mg/L for general reuse was 6 gCOD/L/d and 0.63 gCOD/gMLVSS (mixed liquor volatile suspended solids)/d, respectively. At a high sludge OLR of over 0.6 gCOD/gMLVSS/d, the AnMBR achieved high methane production of over 300 ml/gCOD (even approaching the theoretical value of 382 ml/gCOD). A low biomass production of 0.015-0.026 gMLVSS/gCOD and a sustainable flux of 6L/m(2)/h were observed. The integration of a heat pump and forward osmosis into the mesophilic AnMBR process would be a promising way for net energy recovery from typical municipal wastewater in a temperate area. PMID:24926606

  8. Pathways of energy conservation in methanogenic archaea

    Microsoft Academic Search

    U. Deppenmeier; V. Müller; G. Gottschalk

    1996-01-01

    Methanogenic archaea are strictly anaerobic organisms that derive their metabolic energy from the conversion of a restricted number of substrates to methane. H2 + CO2 and formate are converted to CH4 via the CO2-reducing pathway, while methanol and methylamines are metabolized by the methylotrophic pathway. A limited number of methanogenic organisms utilize acetate by the aceticlastic pathway. Redox reactions involved

  9. Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA

    SciTech Connect

    Bolton, H., Jr.; Bailey, V.L.; Plymale, A.E.; Rai, D.; Xun, L.

    2006-04-05

    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by co-disposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Pu(IV)-EDTA is not stable in the presence of relatively soluble Fe(III) compounds. Since most DOE sites have Fe(III) containing sediments, Pu(IV) is likely not the mobile form of Pu-EDTA. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions and the anaerobic biodegradation of Pu-EDTA. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV), the redox conditions required for this reduction, the strength of the Pu(III)-EDTA, how the Pu(III)-EDTA competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, soluble Pu(III)-EDTA under anaerobic conditions would require anaerobic degradation of the EDTA to limit Pu(III) transport. Anaerobic EDTA degrading microorganisms have never been isolated. Recent results have shown that Shewanella oneidensis MR-1, a dissimilatory metal reducing bacterium, can reduce Pu(IV) to Pu(III). The Pu(IV) was provided as insoluble PuO2. The highest rate of Pu(IV) reduction was with the addition of AQDS, an electron shuttle. Of the total amount of Pu solubilized (i.e., soluble through a 0.36 nm filter), approximately 70% was Pu(III). The amount of soluble Pu was between 4.8 and 3.2 micromolar at day 1 and 6, respectively, indicating rapid reduction. The micromolar Pu is significant since the drinking water limit for Pu is 10{sup -12} M. On-going experiments are investigating the influence of EDTA on the rate of Pu reduction and the stability of the formed Pu(III). We have also begun to enrich and isolate bacteria capable of aerobic and anaerobic degradation of EDTA. Environmental samples (e.g., sludges, river sediments) were incubated aerobically and anaerobically with EDTA or NTA as the sole carbon and energy source. Aerobic enrichment with EDTA has not resulted in any cultures, but NTA has provided several isolates. Partial 16S rRNA gene sequence and sequence comparison identified four separate strains closely related to Microbacterium oxydans, Aminobacter sp., Achromobacter sp., Aminobacter sp., respectively. Anaerobic enrichments with either EDTA or NTA are still in progress since metabolism and growth is relatively slow. In addition to the biotransformation experiments, studies are underway to determine/validate complexation constants of Pu(III) with EDTA and the influence of competing ions on Pu(III)-EDTA complexes. These data are being obtained through solubility studies of PuPO{sub 4}(s) and Pu(OH){sub 3}(s) as a function of time, pH, and EDTA and competing ion concentrations. These results have begun to fill-in knowledge gaps of how anaerobic conditions will influence Pu and Pu-EDTA fate and transport to assess, model, and design approaches to stop Pu transport in groundwater at DOE sites.

  10. Metabolomics Analysis of Cistus monspeliensis Leaf Extract on Energy Metabolism Activation in Human Intestinal Cells

    PubMed Central

    Shimoda, Yoichi; Han, Junkyu; Kawada, Kiyokazu; Smaoui, Abderrazak; Isoda, Hiroko

    2012-01-01

    Energy metabolism is a very important process to improve and maintain health from the point of view of physiology. It is well known that the intracellular ATP production is contributed to energy metabolism in cells. Cistus monspeliensis is widely used as tea, spices, and medical herb; however, it has not been focusing on the activation of energy metabolism. In this study, C. monspeliensis was investigated as the food resources by activation of energy metabolism in human intestinal epithelial cells. C. monspeliensis extract showed high antioxidant ability. In addition, the promotion of metabolites of glycolysis and TCA cycle was induced by C. monspeliensis treatment. These results suggest that C. monspeliensis extract has an ability to enhance the energy metabolism in human intestinal cells. PMID:22523469

  11. Energy Metabolism in Mycobacterium gilvum PYR-GCK: Insights from Transcript Expression Analyses Following Two States of Induction

    PubMed Central

    Badejo, Abimbola Comfort; Chung, Won Hyong; Kim, Nam Shin; Chai, Jin Choul; Lee, Young Seek; Jung, Kyoung Hwa; Kim, Hyo Joon; Chai, Young Gyu

    2014-01-01

    Mycobacterium gilvum PYR-GCK, a pyrene degrading bacterium, has been the subject of functional studies aimed at elucidating mechanisms related to its outstanding pollutant bioremediation/biodegradation activities. Several studies have investigated energy production and conservation in Mycobacterium, however, they all focused on the pathogenic strains using their various hosts as induction sources. To gain greater insight into Mycobacterium energy metabolism, mRNA expression studies focused on respiratory functions were performed under two different conditions using the toxic pollutant pyrene as a test substrate and glucose as a control substrate. This was done using two transcriptomic techniques: global transcriptomic RNA-sequencing and quantitative Real-Time PCR. Growth in the presence of pyrene resulted in upregulated expression of genes associated with limited oxygen or anaerobiosis in M.gilvum PYR-GCK. Upregulated genes included succinate dehydrogenases, nitrite reductase and various electron donors including formate dehydrogenases, fumarate reductases and NADH dehydrogenases. Oxidative phosphorylation genes (with respiratory chain complexes I, III –V) were expressed at low levels compared to the genes coding for the second molecular complex in the bacterial respiratory chain (fumarate reductase); which is highly functional during microaerophilic or anaerobic bacterial growth. This study reveals a molecular adaptation to a hypoxic mode of respiration during aerobic pyrene degradation. This is likely the result of a cellular oxygen shortage resulting from exhaustion of the oxygenase enzymes required for these degradation activities in M.gilvum PYR-GCK. PMID:24927157

  12. Process configuration role in anaerobic biotransformations

    SciTech Connect

    Speece, R.E.

    1998-07-01

    Defining the environmental conditions which would enable anaerobic processes to consistently produce effluents containing only non-detectable concentrations of degradable organics would remove one of the main drawbacks to wider application of this important treatment technology. Recently specific metabolic intermediates formed in the anaerobic biotransformation of complex organics have been found to enhance or curtail process performance. Using acrylate and acrolein as representative hazardous chemicals, modifications in staging and reactor operation procedures have been observed in the author's laboratory to profoundly impact the rate and completeness of the biotransformation process. Specific metabolic intermediates formed in the biotransformation of complex substrates to a large extent will control a given process performance and process configuration greatly impacts the metabolic pathway, thus impacting the intermediates formed as well. There is a growing body of literature to indicate that process performance in anaerobic biotransformation is greatly impacted by reactor configuration. There is also some evidence that metabolic precursors impact the subsequent efficiency of conversion of volatile fatty acids (VFA) ultimately to CH{sub 4}. But although profound differences in the performance of anaerobic biotransformation are reported for various process configurations, there are no published criteria to guide the rational design of stages/phased processes. Clarification of the relative merits of single stage, two stage, two phase, granules and biofilms as well as CSTR and plug flow modes in the biotransformation of hazardous pollutants would be foundational for future research and development.

  13. Metabolic energy from arsenite oxidation in Alcaligenes faecalis

    NASA Astrophysics Data System (ADS)

    Anderson, G. L.; Love, M.; Zeider, B. K.

    2003-05-01

    The aerobic soil bacterium, Alcaligenes faecalis, survives in cultures containing greater than 10 g/L of aqueous arsenic. Toleration of arsenite occurs by the enzymatic oxidation of arsenite (As^III), to the less toxic arsenate (As^V). In defined media, the bacterium grows faster in the presence of arsenite than in its absence. This suggests that the bacterium uses the redox potential of arsenite oxidation as metabolic energy. The oxidation occurs via periplasmic arsenite oxidase, azurin, and cytochrome c [11] which presumably pass electron equivalents through an electron transport chain involving cytochrome c oxidase aud oxygen as the terminal electron acceptor. The associated proton translocation would allow synthesis of ATP and provide a useful means of harnessing the redox potential of arsenite oxidation. Arsenite and arsenate assays of the media during bacterial growth indicate that arsenite is depleted during the exponential growth phase and occurs concomitantly with the expression of arsenite oxidase. These results suggest that arsenite is detoxified to arsenate during bacterial growth and are inconsistent with previous reported interpretations of growth data. Alcaligenes faecalis is dependent on organic carbon sources and is therefore not chemolithoautotrophic. The relationship between succinate and arsenite utilisation provides evidence for the use of arsenite as a supplemental energy source. Because Alcaligenes faecalis not only tolerates, but thrives, in very high concentrations of arsenic has important implications in bioremediation of environments contaminated by aqueous arsenic.

  14. Growth states of catalytic reaction networks exhibiting energy metabolism.

    PubMed

    Kondo, Yohei; Kaneko, Kunihiko

    2011-07-01

    All cells derive nutrition by absorbing some chemical and energy resources from the environment; these resources are used by the cells to reproduce the chemicals within them, which in turn leads to an increase in their volume. In this study we introduce a protocell model exhibiting catalytic reaction dynamics, energy metabolism, and cell growth. Results of extensive simulations of this model show the existence of four phases with regard to the rates of both the influx of resources and cell growth. These phases include an active phase with high influx and high growth rates, an inefficient phase with high influx but low growth rates, a quasistatic phase with low influx and low growth rates, and a death phase with negative growth rate. A mean field model well explains the transition among these phases as bifurcations. The statistical distribution of the active phase is characterized by a power law, and that of the inefficient phase is characterized by a nearly equilibrium distribution. We also discuss the relevance of the results of this study to distinct states in the existing cells. PMID:21867233

  15. Effect of metabolic structures and energy requirements on curdlan production by Alcaligenes faecalis

    Microsoft Academic Search

    Zhi-Yong Zheng; Jin Woo Lee; Xiao Bei Zhan; Zhongping Shi; Lei Wang; Li Zhu; Jian-Rong Wu; Chi Chung Lin

    2007-01-01

    A comprehensive metabolic network was proposed forAlcaligenes faecalis and employed in a stoichiometrically based flux balance model for curdlan production optimization. The maximal yield of curdlan\\u000a was evaluated for curdlan batch production. Various metabolic structures and metabolic pathway distributions related with\\u000a the curdlan maximal yield was evaluated. The results showed that the energy efficiency rather than the substrate supply was

  16. NAD(+) Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus.

    PubMed

    Cantó, Carles; Menzies, Keir J; Auwerx, Johan

    2015-07-01

    NAD(+) has emerged as a vital cofactor that can rewire metabolism, activate sirtuins, and maintain mitochondrial fitness through mechanisms such as the mitochondrial unfolded protein response. This improved understanding of NAD(+) metabolism revived interest in NAD(+)-boosting strategies to manage a wide spectrum of diseases, ranging from diabetes to cancer. In this review, we summarize how NAD(+) metabolism links energy status with adaptive cellular and organismal responses and how this knowledge can be therapeutically exploited. PMID:26118927

  17. Effects of copper exposure on the energy metabolism in juveniles of the marine clam Mesodesma mactroides.

    PubMed

    Giacomin, Marina; Jorge, Marianna Basso; Bianchini, Adalto

    2014-07-01

    In freshwater osmoregulating mollusks, Cu can cause toxicity by inducing ionoregulatory disturbances. In mussels, it inhibits the activity of key enzymes involved in Na(+) uptake and consequently induces ionic and osmotic disturbances. In snails, Cu induces disruption of the Ca(2+) homeostasis leading to effects in shell deposition and snail growth. However, the mechanisms involved in Cu toxicity in osmoconforming sweater mollusks remain unclear. Recent findings from our laboratory have suggested that Cu toxicity in marine invertebrates can be associated with both ionic and respiratory disturbances. In the present study, metabolic changes induced by waterborne Cu exposure were evaluated in the osmoconforming clam Mesodesma mactroides, a bivalve species widely distributed along the South American sandy beaches. Juvenile clams were kept under control conditions (no Cu addition in the water) or acutely (96h) exposed to Cu (96-h LC10=150?gL(-1)) in artificial seawater (30ppt). ATP, protein, lipid, glycogen and glucose contents were analyzed in gills, digestive gland, pedal muscle and hemolymph. Dinucleotide (NAD(+) and NADH) content was also analyzed in gills, digestive gland and pedal muscle while pyruvate and lactate content was determined in pedal muscle and hemolymph. In all tissues analyzed, Cu exposure did not affect ATP content and NAD(+)/NADH ratio, except in the hemolymph, where a decrease in ATP content was observed. These findings indicate that clam cells, except those from hemolymph, were able to maintain a constant level of free energy. A significant increase in total protein content was observed in the digestive gland, which could be a compensatory mechanism to counteract the higher level of protein oxidation previously observed in M. mactroides exposed to Cu under the same experimental conditions. Finally, reduced glucose content in the pedal muscle paralleled by increased lactate content in the pedal muscle and hemolymph was observed in Cu-exposed clams. Overall, these findings indicate that Cu exposure is leading to an increased reliance upon the anaerobic energy production to maintain the overall cellular ATP production in the clam M. mactroides. PMID:24727213

  18. DESIGN OF AN ANAEROBIC DIGESTER AND FUEL CELL SYSTEM FOR ENERGY GENERATION FROM DAIRY WASTE

    EPA Science Inventory

    Dairy waste was found to have a natural population of microorganisms capable of seeding an MFC. Dairy wastewater also proved to be a very effective substrate. Different graphite electrode materials provided varying levels of electrical energy generation, demonstrating with gr...

  19. Transcriptional regulation and energetics of alternative respiratory pathways in facultatively anaerobic bacteria

    Microsoft Academic Search

    Gottfried Unden

    1998-01-01

    The facultatively anaerobic Escherichia coli is able to grow by aerobic and by anaerobic respiration. Despite the large difference in the amount of free energy that could maximally be conserved from aerobic versus anaerobic respiration, the proton potential and ?g?Phos are similar under both conditions. O2 represses anaerobic respiration, and nitrate represses fumarate respiration. By this the terminal reductases of

  20. Limits of anaerobic biodegradation

    Microsoft Academic Search

    J. A. Field

    2002-01-01

    The main factors responsible for anaerobic recalcitrance are reviewed. Anaerobic recalcitrance is associated with hydrocarbons lacking functional groups, branched molecules (gasoline oxygenates), aromatic amines and aromatic sulfonates. The most recalcitrant compounds are high molecular weight non- hydrolyzable polymers such as plastic, lignin and humus, which cannot be taken up by cells. Recently new capabilities of anaerobic microorganisms have been discovered

  1. EFFECT OF LEVEL OF INTAKE AND DIET DILUTION ON ENERGY METABOLISM IN THE YOUNG PIG 1

    Microsoft Academic Search

    L. W. De Goey; R. C. Ewan

    Summary Two trials were conducted to study energy metabolism in young pigs. Feeding a highly fortified diet at levels from 2 to 5% body weight did not affect the apparent digestibility coefficients for dry matter, nitrogen or energy. Digestible energy (DE) or metabolizable energy (ME) of the diet was not affected by level of feeding. Metabolizable energy averaged 94% of

  2. Highly energy efficient: Wilton wastewater treatment plant. [Heats building, hot water supply, and anaerobic digesters

    Microsoft Academic Search

    D. A. Wilke; D. R. Fuller

    1976-01-01

    The project encompasses the design, construction, and operation of the Wilton, Maine, municipal wastewater treatment plant. The basic concept of the design is to minimize the requirements for off-site energy sources. Since the stream receiving the treated effluent is small and vulnerable to drought conditions, provisions had to be made for handling the effluent during extremely low stream-flow conditions. The

  3. Anaerobic electron acceptor chemotaxis in Shewanella putrefaciens

    NASA Technical Reports Server (NTRS)

    Nealson, K. H.; Moser, D. P.; Saffarini, D. A.

    1995-01-01

    Shewanella putrefaciens MR-1 can grow either aerobically or anaerobically at the expense of many different electron acceptors and is often found in abundance at redox interfaces in nature. Such redox interfaces are often characterized by very strong gradients of electron acceptors resulting from rapid microbial metabolism. The coincidence of S. putrefaciens abundance with environmental gradients prompted an examination of the ability of MR-1 to sense and respond to electron acceptor gradients in the laboratory. In these experiments, taxis to the majority of the electron acceptors that S. putrefaciens utilizes for anaerobic growth was seen. All anaerobic electron acceptor taxis was eliminated by the presence of oxygen, nitrate, nitrite, elemental sulfur, or dimethyl sulfoxide, even though taxis to the latter was very weak and nitrate and nitrite respiration was normal in the presence of dimethyl sulfoxide. Studies with respiratory mutants of MR-1 revealed that several electron acceptors that could not be used for anaerobic growth nevertheless elicited normal anaerobic taxis. Mutant M56, which was unable to respire nitrite, showed normal taxis to nitrite, as well as the inhibition of taxis to other electron acceptors by nitrite. These results indicate that electron acceptor taxis in S. putrefaciens does not conform to the paradigm established for Escherichia coli and several other bacteria. Carbon chemo-taxis was also unusual in this organism: of all carbon compounds tested, the only positive response observed was to formate under anaerobic conditions.

  4. AMPK in the regulation of hepatic energy metabolism: from physiology to therapeutic perspectives.

    E-print Network

    Paris-Sud XI, Université de

    production, fatty liver type 2 diabetes. Abstract Because the liver is central in the maintenance of glucose regulated according to needs. Fatty liver and hepatic insulin resistance (both frequently associated: AMPK in the liver Key words: AMPK, energy metabolism, liver, metabolic disorders, hepatic glucose

  5. CO sub 2 incorporation and 4-hydroxy-2-methylbenzoic acid formation during anaerobic metabolism of m-cresol by a methanogenic consortium

    SciTech Connect

    Roberts, D.J.; Fedorak, P.M.; Hrudey, S.E. (Univ. of Alberta, Edmonton (Canada))

    1990-02-01

    The metabolism of m-cresol by methanogenic cultures enriched from domestic sewage sludge was investigated. In the initial studies, bromoethanesulfonic acid was used to inhibit methane production. This led to the accumulation of 4.0 {+-} 0.8 mol of acetate per mol of m-cresol metabolized. These results suggested that CO{sub 2} incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas four molecules of acetate product contained a total of eight carbon atoms. To verify this, ({sup 14}C)bicarbonate was added to bromoethanesulfonic acid-inhibited cultures, and those cultures yielded ({sup 14}C)acetate. Of the label recovered as acetate, 89% was found in the carboxyl position. Similar cultures fed (methyl-{sup 14}C)m-cresol yielded methyl-labeled acetate. A {sup 14}C-labeled transient intermediate was detected in cultures given either m-cresol and ({sup 14}C)bicarbonate or bicarbonate and (methyl-{sup 14}C)m-cresol. The intermediate was identified as 4-hydroxy-2-methylbenzoic acid. In addition, another metabolite was detected and identified as 2-methylbenzoic acid. This compound appeared to be produced only sporadically, and it accumulated in the medium, suggested that the dehydroxylation of 4-hydroxy-2-methylbenzoic acid led to an apparent dead-end product.

  6. Thyroid hormones correlate with resting metabolic rate, not daily energy expenditure, in two charadriiform seabirds.

    PubMed

    Elliott, Kyle H; Welcker, Jorg; Gaston, Anthony J; Hatch, Scott A; Palace, Vince; Hare, James F; Speakman, John R; Anderson, W Gary

    2013-06-15

    Thyroid hormones affect in vitro metabolic intensity, increase basal metabolic rate (BMR) in the lab, and are sometimes correlated with basal and/or resting metabolic rate (RMR) in a field environment. Given the difficulty of measuring metabolic rate in the field-and the likelihood that capture and long-term restraint necessary to measure metabolic rate in the field jeopardizes other measurements-we examined the possibility that circulating thyroid hormone levels were correlated with RMR in two free-ranging bird species with high levels of energy expenditure (the black-legged kittiwake, Rissa tridactyla, and thick-billed murre, Uria lomvia). Because BMR and daily energy expenditure (DEE) are purported to be linked, we also tested for a correlation between thyroid hormones and DEE. We examined the relationships between free and bound levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) with DEE and with 4-hour long measurements of post-absorptive and thermoneutral resting metabolism (resting metabolic rate; RMR). RMR but not DEE increased with T3 in both species; both metabolic rates were independent of T4. T3 and T4 were not correlated with one another. DEE correlated with body mass in kittiwakes but not in murres, presumably owing to the larger coefficient of variation in body mass during chick rearing for the more sexually dimorphic kittiwakes. We suggest T3 provides a good proxy for resting metabolism but not DEE in these seabird species. PMID:23789108

  7. Thyroid hormones correlate with resting metabolic rate, not daily energy expenditure, in two charadriiform seabirds

    PubMed Central

    Elliott, Kyle H.; Welcker, Jorg; Gaston, Anthony J.; Hatch, Scott A.; Palace, Vince; Hare, James F.; Speakman, John R.; Anderson, W. Gary

    2013-01-01

    Summary Thyroid hormones affect in vitro metabolic intensity, increase basal metabolic rate (BMR) in the lab, and are sometimes correlated with basal and/or resting metabolic rate (RMR) in a field environment. Given the difficulty of measuring metabolic rate in the field—and the likelihood that capture and long-term restraint necessary to measure metabolic rate in the field jeopardizes other measurements—we examined the possibility that circulating thyroid hormone levels were correlated with RMR in two free-ranging bird species with high levels of energy expenditure (the black-legged kittiwake, Rissa tridactyla, and thick-billed murre, Uria lomvia). Because BMR and daily energy expenditure (DEE) are purported to be linked, we also tested for a correlation between thyroid hormones and DEE. We examined the relationships between free and bound levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) with DEE and with 4-hour long measurements of post-absorptive and thermoneutral resting metabolism (resting metabolic rate; RMR). RMR but not DEE increased with T3 in both species; both metabolic rates were independent of T4. T3 and T4 were not correlated with one another. DEE correlated with body mass in kittiwakes but not in murres, presumably owing to the larger coefficient of variation in body mass during chick rearing for the more sexually dimorphic kittiwakes. We suggest T3 provides a good proxy for resting metabolism but not DEE in these seabird species. PMID:23789108

  8. Transcriptional Factors Mediating Retinoic Acid Signals in the Control of Energy Metabolism

    PubMed Central

    Zhang, Rui; Wang, Yueqiao; Li, Rui; Chen, Guoxun

    2015-01-01

    Retinoic acid (RA), an active metabolite of vitamin A (VA), is important for many physiological processes including energy metabolism. This is mainly achieved through RA-regulated gene expression in metabolically active cells. RA regulates gene expression mainly through the activation of two subfamilies in the nuclear receptor superfamily, retinoic acid receptors (RARs) and retinoid X receptors (RXRs). RAR/RXR heterodimers or RXR/RXR homodimers bind to RA response element in the promoters of RA target genes and regulate their expressions upon ligand binding. The development of metabolic diseases such as obesity and type 2 diabetes is often associated with profound changes in the expressions of genes involved in glucose and lipid metabolism in metabolically active cells. RA regulates some of these gene expressions. Recently, in vivo and in vitro studies have demonstrated that status and metabolism of VA regulate macronutrient metabolism. Some studies have shown that, in addition to RARs and RXRs, hepatocyte nuclear factor 4?, chicken ovalbumin upstream promoter-transcription factor II, and peroxisome proliferator activated receptor ?/? may function as transcriptional factors mediating RA response. Herein, we summarize current progresses regarding the VA metabolism and the role of nuclear receptors in mediating RA signals, with an emphasis on their implication in energy metabolism. PMID:26110391

  9. Transcriptional Factors Mediating Retinoic Acid Signals in the Control of Energy Metabolism.

    PubMed

    Zhang, Rui; Wang, Yueqiao; Li, Rui; Chen, Guoxun

    2015-01-01

    Retinoic acid (RA), an active metabolite of vitamin A (VA), is important for many physiological processes including energy metabolism. This is mainly achieved through RA-regulated gene expression in metabolically active cells. RA regulates gene expression mainly through the activation of two subfamilies in the nuclear receptor superfamily, retinoic acid receptors (RARs) and retinoid X receptors (RXRs). RAR/RXR heterodimers or RXR/RXR homodimers bind to RA response element in the promoters of RA target genes and regulate their expressions upon ligand binding. The development of metabolic diseases such as obesity and type 2 diabetes is often associated with profound changes in the expressions of genes involved in glucose and lipid metabolism in metabolically active cells. RA regulates some of these gene expressions. Recently, in vivo and in vitro studies have demonstrated that status and metabolism of VA regulate macronutrient metabolism. Some studies have shown that, in addition to RARs and RXRs, hepatocyte nuclear factor 4?, chicken ovalbumin upstream promoter-transcription factor II, and peroxisome proliferator activated receptor ?/? may function as transcriptional factors mediating RA response. Herein, we summarize current progresses regarding the VA metabolism and the role of nuclear receptors in mediating RA signals, with an emphasis on their implication in energy metabolism. PMID:26110391

  10. Sawyeria marylandensis (Heterolobosea) Has a Hydrogenosome with Novel Metabolic Properties ? †

    PubMed Central

    Barberà, Maria José; Ruiz-Trillo, Iñaki; Tufts, Julia Y. A.; Bery, Amandine; Silberman, Jeffrey D.; Roger, Andrew J.

    2010-01-01

    Protists that live under low-oxygen conditions often lack conventional mitochondria and instead possess mitochondrion-related organelles (MROs) with distinct biochemical functions. Studies of mostly parasitic organisms have suggested that these organelles could be classified into two general types: hydrogenosomes and mitosomes. Hydrogenosomes, found in parabasalids, anaerobic chytrid fungi, and ciliates, metabolize pyruvate anaerobically to generate ATP, acetate, CO2, and hydrogen gas, employing enzymes not typically associated with mitochondria. Mitosomes that have been studied have no apparent role in energy metabolism. Recent investigations of free-living anaerobic protists have revealed a diversity of MROs with a wider array of metabolic properties that defy a simple functional classification. Here we describe an expressed sequence tag (EST) survey and ultrastructural investigation of the anaerobic heteroloboseid amoeba Sawyeria marylandensis aimed at understanding the properties of its MROs. This organism expresses typical anaerobic energy metabolic enzymes, such as pyruvate:ferredoxin oxidoreductase, [FeFe]-hydrogenase, and associated hydrogenase maturases with apparent organelle-targeting peptides, indicating that its MRO likely functions as a hydrogenosome. We also identified 38 genes encoding canonical mitochondrial proteins in S. marylandensis, many of which possess putative targeting peptides and are phylogenetically related to putative mitochondrial proteins of its heteroloboseid relative Naegleria gruberi. Several of these proteins, such as a branched-chain alpha keto acid dehydrogenase, likely function in pathways that have not been previously associated with the well-studied hydrogenosomes of parabasalids. Finally, morphological reconstructions based on transmission electron microscopy indicate that the S. marylandensis MROs form novel cup-like structures within the cells. Overall, these data suggest that Sawyeria marylandensis possesses a hydrogenosome of mitochondrial origin with a novel combination of biochemical and structural properties. PMID:21037180

  11. Metabolic Plasticity and Hematopoietic Stem Cell Biology

    PubMed Central

    Hsu, Peter; Qu, Cheng-Kui

    2013-01-01

    Purpose of review Hematopoietic stem cells (HSCs) residing in the hypoxic niches can both self-renew and give rise to progeny. Multiple regulatory mechanisms for these cellular processes have been identified. Emerging evidence has revealed that metabolism and bioenergetics play important roles in determining stem cell fate in concert with other regulatory networks. In this review, we will discuss recent advances in this field. Recent findings Recent studies have helped define and redefine metabolic regulation of HSCs. Resting quiescent stem cells use primarily anaerobic glycolysis for energy production and this metabolic program is required to maintain a functional quiescent state. However, when they exit this state and rapidly proliferate and differentiate into different blood cell types, a robust upregulation of energy metabolism is expected to meet the quickly rising energy demand. Dysregulation of metabolism in HSCs results in various blood disorders, including leukemia. Summary Energy metabolism and HSC activity influence and interlink each other in a highly sophisticated and orchestrated manner. Understanding metabolic regulation of HSC function has significant implications for HSC-based therapies and leukemogenesis research. PMID:23615055

  12. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  13. Protein phosphorylation and prevention of cytochrome oxidase inhibition by ATP: coupled mechanisms of energy metabolism regulation

    PubMed Central

    Acin-Perez, Rebeca; Gatti, Domenico L.; Bai, Yidong; Manfredi, Giovanni

    2011-01-01

    Summary Rapid regulation of oxidative phosphorylation is crucial for mitochondrial adaptation to swift changes in fuels availability and energy demands. An intra-mitochondrial signaling pathway regulates cytochrome oxidase (COX), the terminal enzyme of the respiratory chain, through reversible phosphorylation. We find that PKA-mediated phosphorylation of a COX subunit dictates mammalian mitochondrial energy fluxes, and identify the specific residue (S58) of COX subunit IV-1 (COXIV-1) that is involved in this mechanism of metabolic regulation. Using protein mutagenesis, molecular dynamics simulations, and induced fit docking, we show that mitochondrial energy metabolism regulation by phosphorylation of COXIV-1 is coupled with prevention of COX allosteric inhibition by ATP. This regulatory mechanism is essential for efficient oxidative metabolism and cell survival. We propose that S58 COXIV-1 phosphorylation has evolved as a metabolic switch that allows mammalian mitochondria to rapidly toggle between energy utilization and energy storage. PMID:21641552

  14. Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

    PubMed Central

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F.; Valderrama, J. Andrés; Barragán, María J. L.; García, José Luis; Díaz, Eduardo

    2009-01-01

    Summary: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach. PMID:19258534

  15. Bone: from a reservoir of minerals to a regulator of energy metabolism

    PubMed Central

    Confavreux, Cyrille B

    2011-01-01

    Besides locomotion, organ protection, and calcium–phosphorus homeostasis, the three classical functions of the skeleton, bone remodeling affects energy metabolism through uncarboxylated osteocalcin, a recently discovered hormone secreted by osteoblasts. This review traces how energy metabolism affects osteoblasts through the central control of bone mass involving leptin, serotoninergic neurons, the hypothalamus, and the sympathetic nervous system. Next, the role of osteocalcin (insulin secretion, insulin sensitivity, and pancreas ?-cell proliferation) in the regulation of energy metabolism is described. Then, the connections between insulin signaling on osteoblasts and the release of uncarboxylated osteocalcin during osteoclast bone resorption through osteoprotegerin are reported. Finally, the understanding of this new bone endocrinology will provide some insights into bone, kidney, and energy metabolism in patients with chronic kidney disease. PMID:21346725

  16. Energy metabolism in adult neural stem cell fate Victoria A. Rafalski a,b

    E-print Network

    Brunet, Anne

    Energy metabolism in adult neural stem cell fate Victoria A. Rafalski a,b , Anne Brunet a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 2. Adult neural stem cell properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 2.1. Adult neural stem cells

  17. Energy Metabolism and Drug Efflux in Mycobacterium tuberculosis

    PubMed Central

    Black, Philippa A.; Warren, Robin M.; Louw, Gail E.; van Helden, Paul D.; Victor, Thomas C.

    2014-01-01

    The inherent drug susceptibility of microorganisms is determined by multiple factors, including growth state, the rate of drug diffusion into and out of the cell, and the intrinsic vulnerability of drug targets with regard to the corresponding antimicrobial agent. Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), remains a significant source of global morbidity and mortality, further exacerbated by its ability to readily evolve drug resistance. It is well accepted that drug resistance in M. tuberculosis is driven by the acquisition of chromosomal mutations in genes encoding drug targets/promoter regions; however, a comprehensive description of the molecular mechanisms that fuel drug resistance in the clinical setting is currently lacking. In this context, there is a growing body of evidence suggesting that active extrusion of drugs from the cell is critical for drug tolerance. M. tuberculosis encodes representatives of a diverse range of multidrug transporters, many of which are dependent on the proton motive force (PMF) or the availability of ATP. This suggests that energy metabolism and ATP production through the PMF, which is established by the electron transport chain (ETC), are critical in determining the drug susceptibility of M. tuberculosis. In this review, we detail advances in the study of the mycobacterial ETC and highlight drugs that target various components of the ETC. We provide an overview of some of the efflux pumps present in M. tuberculosis and their association, if any, with drug transport and concomitant effects on drug resistance. The implications of inhibiting drug extrusion, through the use of efflux pump inhibitors, are also discussed. PMID:24614376

  18. In vivo imaging of cerebral energy metabolism with two-photon fluorescence lifetime microscopy of NADH

    PubMed Central

    Yaseen, Mohammad A.; Sakadži?, Sava; Wu, Weicheng; Becker, Wolfgang; Kasischke, Karl A.; Boas, David A.

    2013-01-01

    Minimally invasive, specific measurement of cellular energy metabolism is crucial for understanding cerebral pathophysiology. Here, we present high-resolution, in vivo observations of autofluorescence lifetime as a biomarker of cerebral energy metabolism in exposed rat cortices. We describe a customized two-photon imaging system with time correlated single photon counting detection and specialized software for modeling multiple-component fits of fluorescence decay and monitoring their transient behaviors. In vivo cerebral NADH fluorescence suggests the presence of four distinct components, which respond differently to brief periods of anoxia and likely indicate different enzymatic formulations. Individual components show potential as indicators of specific molecular pathways involved in oxidative metabolism. PMID:23412419

  19. Energy, substrate and protein metabolism in morbid obesity before, during and after massive weight loss

    Microsoft Academic Search

    WG van Gemert; KR Westerterp; BAC van Acker; AJM Wagenmakers; D Halliday; JM Greve; PB Soeters

    2000-01-01

    OBJECTIVE: To investigate the effect of surgically induced weight loss on energy, substrate and protein metabolism of morbidly obese patients.DESIGN: A prospective, clinical intervention study of morbidly obese patients before and after surgical treatment.SUBJECTS: Eight morbidly obese patients (BMI 47.88±7.03).METHODS: Total energy expenditure (TEE; doubly labeled water method), sleeping metabolic rate (SMR; respiration chamber), body composition (deuterium oxide component of

  20. Natural compounds regulate energy metabolism by the modulating the activity of lipid-sensing nuclear receptors.

    PubMed

    Goto, Tsuyoshi; Kim, Young-Il; Takahashi, Nobuyuki; Kawada, Teruo

    2013-01-01

    Obesity causes excess fat accumulation in various tissues, most notoriously in the adipose tissue, along with other insulin-responsive organs such as skeletal muscle and the liver, which predisposes an individual to the development of metabolic abnormalities. The molecular mechanisms underlying obesity-induced metabolic abnormalities have not been completely elucidated; however, in recent years, the search for therapies to prevent the development of obesity and obesity-associated metabolic disorders has increased. It is known that several nuclear receptors, when activated by specific ligands, regulate carbohydrate and lipid metabolism at the transcriptional level. The expression of lipid metabolism-related enzymes is directly regulated by the activity of various nuclear receptors via their interaction with specific response elements in promoters of those genes. Many natural compounds act as ligands of nuclear receptors and regulate carbohydrate and lipid metabolism by regulating the activities of these nuclear receptors. In this review, we describe our current knowledge of obesity, the role of lipid-sensing nuclear receptors in energy metabolism, and several examples of food factors that act as agonists or antagonists of nuclear receptors, which may be useful for the management of obesity and the accompanying energy metabolism abnormalities. PMID:23180608

  1. The Central Carbon and Energy Metabolism of Marine Diatoms

    PubMed Central

    Obata, Toshihiro; Fernie, Alisdair R.; Nunes-Nesi, Adriano

    2013-01-01

    Diatoms are heterokont algae derived from a secondary symbiotic event in which a eukaryotic host cell acquired an eukaryotic red alga as plastid. The multiple endosymbiosis and horizontal gene transfer processes provide diatoms unusual opportunities for gene mixing to establish distinctive biosynthetic pathways and metabolic control structures. Diatoms are also known to have significant impact on global ecosystems as one of the most dominant phytoplankton species in the contemporary ocean. As such their metabolism and growth regulating factors have been of particular interest for many years. The publication of the genomic sequences of two independent species of diatoms and the advent of an enhanced experimental toolbox for molecular biological investigations have afforded far greater opportunities than were previously apparent for these species and re-invigorated studies regarding the central carbon metabolism of diatoms. In this review we discuss distinctive features of the central carbon metabolism of diatoms and its response to forthcoming environmental changes and recent advances facilitating the possibility of industrial use of diatoms for oil production. Although the operation and importance of several key pathways of diatom metabolism have already been demonstrated and determined, we will also highlight other potentially important pathways wherein this has yet to be achieved. PMID:24957995

  2. Comparing environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy--a life cycle perspective.

    PubMed

    De Vries, J W; Vinken, T M W J; Hamelin, L; De Boer, I J M

    2012-12-01

    The aim of this work was to assess the environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy, from a life cycle perspective. This included assessing environmental impacts and land use change emissions (LUC) required to replace used co-substrates for anaerobic digestion. Environmental impact categories considered were climate change, terrestrial acidification, marine and freshwater eutrophication, particulate matter formation, land use, and fossil fuel depletion. Six scenarios were evaluated: mono-digestion of manure, co-digestion with: maize silage, maize silage and glycerin, beet tails, wheat yeast concentrate (WYC), and roadside grass. Mono-digestion reduced most impacts, but represented a limited source for bio-energy. Co-digestion with maize silage, beet tails, and WYC (competing with animal feed), and glycerin increased bio-energy production (up to 568%), but at expense of increasing climate change (through LUC), marine eutrophication, and land use. Co-digestion with wastes or residues like roadside grass gave the best environmental performance. PMID:23026340

  3. Energy requirements, protein-energy metabolism and balance, and carbohydrates in preterm infants.

    PubMed

    Hay, William W; Brown, Laura D; Denne, Scott C

    2014-01-01

    Energy is necessary for all vital functions of the body at molecular, cellular, organ, and systemic levels. Preterm infants have minimum energy requirements for basal metabolism and growth, but also have requirements for unique physiology and metabolism that influence energy expenditure. These include body size, postnatal age, physical activity, dietary intake, environmental temperatures, energy losses in the stool and urine, and clinical conditions and diseases, as well as changes in body composition. Both energy and protein are necessary to produce normal rates of growth. Carbohydrates (primarily glucose) are principle sources of energy for the brain and heart until lipid oxidation develops over several days to weeks after birth. A higher protein/energy ratio is necessary in most preterm infants to approximate normal intrauterine growth rates. Lean tissue is predominantly produced during early gestation, which continues through to term. During later gestation, fat accretion in adipose tissue adds increasingly large caloric requirements to the lean tissue growth. Once protein intake is sufficient to promote net lean body accretion, additional energy primarily produces more body fat, which increases almost linearly at energy intakes >80-90 kcal/kg/day in normal, healthy preterm infants. Rapid gains in adiposity have the potential to produce later life obesity, an increasingly recognized risk of excessive energy intake. In addition to fundamental requirements for glucose, protein, and fat, a variety of non-glucose carbohydrates found in human milk may have important roles in promoting growth and development, as well as production of a gut microbiome that could protect against necrotizing enterocolitis. PMID:24751622

  4. Biochemistry and physiology of anaerobic bacteria

    SciTech Connect

    NONE

    2000-05-18

    We welcome you to The Power of Anaerobes. This conference serves two purposes. One is to celebrate the life of Harry D. Peck, Jr.,who was born May 18, 1927 and would have celebrated his 73rd birthday at this conference. He died November 20, 1998. The second is to gather investigators to exchange views within the realm of anaerobic microbiology, an area in which tremendous progress has been seen during recent years. It is sufficient to mention discoveries of a new form of life (the archaea), hyper or extreme thermophiles, thermophilic alkaliphiles and anaerobic fungi. With these discoveries has come a new realization about physiological and metabolic properties of microorganisms, and this in turn has demonstrated their importance for the development, maintenance and sustenance of life on Earth.

  5. Aerobic versus anaerobic wastewater treatment

    SciTech Connect

    Robinson, D.G.; White, J.E.; Callier, A.J. [Burns and McDonnell Engineering Co., Kansas City, MO (United States)

    1997-04-01

    Biological wastewater treatment facilities are designed to emulate the purification process that occurs naturally in rivers, lakes and streams. In the simulated environment, conditions are carefully manipulated to spur the degradation of organic contaminants and stabilize the residual sludge. Whether the treatment process is aerobic or anaerobic is determined by a number of factors, including the composition of the wastewater, the degree of stabilization required for environmental compliance and economic viability. Because anaerobic digestion is accomplished without oxygen in a closed system, it is economical for pretreatment of high-strength organic sludge. Before the effluent can be discharged, however, followup treatment using an aerobic process is required. Though it has the drawback of being energy intensive, aerobic processing, the aeration of organic sludges in an open tank, is the primary method for treatment of industrial and municipal wastewater. Aerobic processes are more stable than anaerobic approaches and can be done rather simply, particularly with trickling filters. Gradually, the commercialization of modular systems that are capable of aerobic and anaerobic digestion will blur the distinctions between the two processes. Systems that boast those capabilities are available now.

  6. NanR, a Transcriptional Regulator That Binds to the Promoters of Genes Involved in Sialic Acid Metabolism in the Anaerobic Pathogen Clostridium perfringens

    PubMed Central

    Therit, Blair; Cheung, Jackie K.; Rood, Julian I.; Melville, Stephen B.

    2015-01-01

    Among many other virulence factors, Clostridium perfringens produces three sialidases NanH, NanI and NanJ. NanH lacks a secretion signal peptide and is predicted to be an intracellular enzyme, while NanI and NanJ are secreted. Previously, we had identified part of an operon encoding NanE (epimerase) and NanA (sialic acid lyase) enzymes. Further analysis of the entire operon suggests that it encodes a complete pathway for the transport and metabolism of sialic acid along with a putative transcriptional regulator, NanR. The addition of 30 mM N-acetyl neuraminic acid (Neu5Ac) to a semi-defined medium significantly enhanced the growth yield of strain 13, suggesting that Neu5Ac can be used as a nutrient. C. perfringens strain 13 lacks a nanH gene, but has NanI- and NanJ-encoding genes. Analysis of nanI, nanJ, and nanInanJ mutants constructed by homologous recombination revealed that the expression of the major sialidase, NanI, was induced by the addition of Neu5Ac to the medium, and that in separate experiments, the same was true of a nanI-gusA transcriptional fusion. For the nanI and nanJ genes, primer extension identified three and two putative transcription start sites, respectively. Gel mobility shift assays using purified NanR and DNA from the promoter regions of the nanI and nanE genes showed high affinity, specific binding by NanR. We propose that NanR is a global regulator of sialic acid-associated genes and that it responds, in a positive feedback loop, to the concentration of sialic acid in the cell. PMID:26197388

  7. Systemic investigation of a brain-centered model of the human energy metabolism.

    PubMed

    Göbel, Britta; Langemann, Dirk

    2011-03-01

    The regulation of the human energy metabolism is crucial to ensure the functionality of the entire organism. Deregulations may lead to severe pathologies such as diabetes mellitus and obesity. The decisive role of the brain as active controller and heavy consumer in the complex whole-body energy metabolism is the object of recent research. Latest studies suggest the priority of the brain energy supply in the competition between brain and body periphery for the available energy resources. In this paper, a systemic investigation of the human energy metabolism is presented which consists of a compartment model including periphery, blood, and brain as well as signaling paths via insulin, appetite, and ingestion. The presented dynamical system particularly contains the competition for energy between brain and body periphery. Characteristically, the hormone insulin is regarded as central feedback signal of the brain. The model realistically reproduces the qualitative behavior of the energy metabolism. Short-time observations demonstrate the physiological periodic food intake generating the typical oscillating blood glucose variations. Integration over the daily cycle yields a long-term model which shows a stable behavior in accordance with the homeostatic regulation of the energy metabolism on a long-time scale. Two types of abstract constitutive equations describing the interaction between compartments and signals are taken into consideration. These are nonlinear and linear representatives from the class of feasible relations. The robustness of the model against the choice of the representative relation is linked to evolutionary stability of existing organisms. PMID:20734159

  8. The effect of electrodialytic treatment and Na2H2EDTA addition on methanogenic activity of copper-amended anaerobic granular sludge: treatment costs and energy consumption.

    PubMed

    Virkutyte, Jurate; Rokhina, Ekaterina; Lens, Piet; Jegatheesan, Veeriah

    2011-05-01

    The effect of electrodialytic treatment in terms of a current density, pH and Na(2)H(2)EDTA addition on the methanogenic activity of copper-amended anaerobic granular sludge taken from the UASB reactor from paper mill was evaluated. Moreover, the specific energy consumption and simplified operational and treatment costs were calculated. Addition of Na(2)H(2)EDTA (at pH7.7) to copper-amended sludge resulted in the highest microbial activity (62 mg CH(4)-COD g VSS(-1)day(-1)) suggesting that Na(2)H(2)EDTA decreased the toxic effects of copper on the methanogenic activity of the anaerobic granular sludge. The highest methane production (159 %) was also observed upon Na(2)H(2)EDTA addition and simultaneous electricity application (pH7.7). The energy consumption during the treatment was 560, 840, 1400 and 1680 kW h m(-3) at current densities of 0.23, 0.34, 0.57 and 0.69 mA cm(-2), respectively. This corresponded to a treatment costs in terms of electricity expenditure from 39.2 to 117.6 € per cubic meter of sludge. PMID:21055920

  9. THERMOREGULATION AND ENERGY METABOLISM IN THE NEONATAL PIG

    E-print Network

    Paris-Sud XI, Université de

    of colostrum is associated with a conside- rable increase in the metabolic rate wich contributes to maintenance temperature are closely related to the level of colostrum intake. Failure to provide an adequate thermal environment reduces colostrum intake in the neonatal pig with corresponding effects on the development

  10. Do altered energy metabolism or spontaneous locomotion 'mediate' decelerated senescence?

    PubMed

    Arum, Oge; Dawson, John Alexander; Smith, Daniel Larry; Kopchick, John J; Allison, David B; Bartke, Andrzej

    2015-06-01

    That one or multiple measures of metabolic rate may be robustly associated with, or possibly even causative of, the progression of aging-resultant phenotypes such as lifespan is a long-standing, well-known mechanistic hypothesis. To broach this hypothesis, we assessed metabolic function and spontaneous locomotion in two genetic and one dietary mouse models for retarded aging, and subjected the data to mediation analyses to determine whether any metabolic or locomotor trait could be identified as a mediator of the effect of any of the interventions on senescence. We do not test the hypothesis of causality (which would require some experiments), but instead test whether the correlation structure of certain variables is consistent with one possible pathway model in which a proposed mediating variable has a causal role. Results for metabolic measures, including oxygen consumption and respiratory quotient, failed to support this hypothesis; similar negative results were obtained for three behavioral motion metrics. Therefore, our mediation analyses did not find support that any of these correlates of decelerated senescence was a substantial mediator of the effect of either of these genetic alterations (with or without caloric restriction) on longevity. Further studies are needed to relate the examined phenotypic characteristics to mechanisms of aging and control of longevity. PMID:25720347

  11. ORIGINAL ARTICLE Metabolic and Mechanical Energy Costs of Reducing Vertical

    E-print Network

    during normal walk- ing by able-bodied subjects. Key Words: Biomechanics; Efficiency; Rehabilitation center of mass (COM) displacement will lower the metabolic cost of human walking. To examine changes: Randomized repeated measures. Setting: Human Neuromechanics Laboratory, University of Michigan. Participants

  12. Do altered energy metabolism or spontaneous locomotion ‘mediate’ decelerated senescence?

    PubMed Central

    Arum, Oge; Dawson, John Alexander; Smith, Daniel Larry; Kopchick, John J; Allison, David B; Bartke, Andrzej

    2015-01-01

    That one or multiple measures of metabolic rate may be robustly associated with, or possibly even causative of, the progression of aging-resultant phenotypes such as lifespan is a long-standing, well-known mechanistic hypothesis. To broach this hypothesis, we assessed metabolic function and spontaneous locomotion in two genetic and one dietary mouse models for retarded aging, and subjected the data to mediation analyses to determine whether any metabolic or locomotor trait could be identified as a mediator of the effect of any of the interventions on senescence. We do not test the hypothesis of causality (which would require some experiments), but instead test whether the correlation structure of certain variables is consistent with one possible pathway model in which a proposed mediating variable has a causal role. Results for metabolic measures, including oxygen consumption and respiratory quotient, failed to support this hypothesis; similar negative results were obtained for three behavioral motion metrics. Therefore, our mediation analyses did not find support that any of these correlates of decelerated senescence was a substantial mediator of the effect of either of these genetic alterations (with or without caloric restriction) on longevity. Further studies are needed to relate the examined phenotypic characteristics to mechanisms of aging and control of longevity. PMID:25720347

  13. An anaerobic mitochondrion that produces hydrogen.

    PubMed

    Boxma, Brigitte; de Graaf, Rob M; van der Staay, Georg W M; van Alen, Theo A; Ricard, Guenola; Gabaldón, Toni; van Hoek, Angela H A M; Moon-van der Staay, Seung Yeo; Koopman, Werner J H; van Hellemond, Jaap J; Tielens, Aloysius G M; Friedrich, Thorsten; Veenhuis, Marten; Huynen, Martijn A; Hackstein, Johannes H P

    2005-03-01

    Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolically quite different, just like mitochondria where large differences also exist. These differences have led to a continuing debate about the evolutionary origin of hydrogenosomes. Here we show that the hydrogenosomes of the anaerobic ciliate Nyctotherus ovalis, which thrives in the hindgut of cockroaches, have retained a rudimentary genome encoding components of a mitochondrial electron transport chain. Phylogenetic analyses reveal that those proteins cluster with their homologues from aerobic ciliates. In addition, several nucleus-encoded components of the mitochondrial proteome, such as pyruvate dehydrogenase and complex II, were identified. The N. ovalis hydrogenosome is sensitive to inhibitors of mitochondrial complex I and produces succinate as a major metabolic end product--biochemical traits typical of anaerobic mitochondria. The production of hydrogen, together with the presence of a genome encoding respiratory chain components, and biochemical features characteristic of anaerobic mitochondria, identify the N. ovalis organelle as a missing link between mitochondria and hydrogenosomes. PMID:15744302

  14. Interrelationships between mitochondrial fusion, energy metabolism and oxidative stress during development in Caenorhabditis elegans

    SciTech Connect

    Yasuda, Kayo [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan) [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Education and Research Support Center, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Hartman, Philip S. [Biology Department, Texas Christian University, Fort Worth, TX 76129 (United States)] [Biology Department, Texas Christian University, Fort Worth, TX 76129 (United States); Ishii, Takamasa [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)] [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Suda, Hitoshi [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan)] [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan); Akatsuka, Akira [Education and Research Support Center, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)] [Education and Research Support Center, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Shoyama, Tetsuji [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan)] [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan); Miyazawa, Masaki [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)] [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Ishii, Naoaki, E-mail: nishii@is.icc.u-tokai.ac.jp [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)] [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)

    2011-01-21

    Research highlights: {yields} Growth and development of a fzo-1 mutant defective in the fusion process of mitochondria was delayed relative to the wild type of Caenorhabditis elegans. {yields} Oxygen sensitivity during larval development, superoxide production and carbonyl protein accumulation of the fzo-1 mutant were similar to wild type. {yields} fzo-1 animals had significantly lower metabolism than did N2 and mev-1 overproducing superoxide from mitochondrial electron transport complex II. {yields} Mitochondrial fusion can profoundly affect energy metabolism and development. -- Abstract: Mitochondria are known to be dynamic structures with the energetically and enzymatically mediated processes of fusion and fission responsible for maintaining a constant flux. Mitochondria also play a role of reactive oxygen species production as a byproduct of energy metabolism. In the current study, interrelationships between mitochondrial fusion, energy metabolism and oxidative stress on development were explored using a fzo-1 mutant defective in the fusion process and a mev-1 mutant overproducing superoxide from mitochondrial electron transport complex II of Caenorhabditis elegans. While growth and development of both single mutants was slightly delayed relative to the wild type, the fzo-1;mev-1 double mutant experienced considerable delay. Oxygen sensitivity during larval development, superoxide production and carbonyl protein accumulation of the fzo-1 mutant were similar to wild type. fzo-1 animals had significantly lower metabolism than did N2 and mev-1. These data indicate that mitochondrial fusion can profoundly affect energy metabolism and development.

  15. Beyond Leptin: Emerging Candidates for the Integration of Metabolic and Reproductive Function during Negative Energy Balance

    PubMed Central

    True, Cadence; Grove, Kevin L.; Smith, M. Susan

    2011-01-01

    Reproductive status is tightly coupled to metabolic state in females, and ovarian cycling in mammals is halted when energy output exceeds energy input, a metabolic condition known as negative energy balance. This inhibition of reproductive function during negative energy balance occurs due to suppression of gonadotropin-releasing hormone (GnRH) release in the hypothalamus. The GnRH secretagogue kisspeptin is also inhibited during negative energy balance, indicating that inhibition of reproductive neuroendocrine circuits may occur upstream of GnRH itself. Understanding the metabolic signals responsible for the inhibition of reproductive pathways has been a compelling research focus for many years. A predominant theory in the field is that the status of energy balance is conveyed to reproductive neuroendocrine circuits via the adipocyte hormone leptin. Leptin is stimulatory for GnRH release and lower levels of leptin during negative energy balance are believed to result in decreased stimulatory drive for GnRH cells. However, recent evidence found that restoring leptin to physiological levels did not restore GnRH function in three different models of negative energy balance. This suggests that although leptin may be an important permissive signal for reproductive function as indicated by many years of research, factors other than leptin must critically contribute to negative energy balance-induced reproductive inhibition. This review will focus on emerging candidates for the integration of metabolic status and reproductive function during negative energy balance. PMID:22645510

  16. Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

    SciTech Connect

    Mosey, F.E. [VFA Services Ltd., Herts (United Kingdom)

    1996-01-01

    This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

  17. Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

    SciTech Connect

    Mosey, F.E. [VFA Services Ltd., Herts (United Kingdom)

    1995-11-01

    This paper defines the environmental role of anaerobic digestion with the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

  18. Acute toxicity of boric acid on energy metabolism of the breast muscle in broiler chickens

    Microsoft Academic Search

    Fatime Geyiko?glu; Hasan Türkez

    2007-01-01

    Short-and long-term oral exposures to boric acid (BA) in laboratory animals and birds caused toxic effects. However, the toxicity\\u000a data on adult poultry skeletal muscles of BA was not documented with metabolic studies. Livability, weight gain, and feed\\u000a conversion might be adversely affected in broilers as a result of changes in energy metabolism. Therefore, this study was\\u000a conducted to investigate

  19. Environmental Endocrine Disruption of Energy Metabolism and Cardiovascular Risk

    PubMed Central

    Kirkley, Andrew G.; Sargis, Robert M.

    2014-01-01

    Rates of metabolic and cardiovascular diseases have increased at an astounding rate in recent decades. While poor diet and physical inactivity are central drivers, these lifestyle changes alone fail to fully account for the magnitude and rapidity of the epidemic. Thus, attention has turned to identifying novel risk factors, including the contribution of environmental endocrine disrupting chemicals. Epidemiological and preclinical data support a role for various contaminants in the pathogenesis of diabetes. In addition to the vascular risk associated with dysglycemia, emerging evidence implicates multiple pollutants in the pathogenesis of atherosclerosis and cardiovascular disease. Reviewed herein are studies linking endocrine disruptors to these key diseases that drive significant individual and societal morbidity and mortality. Identifying chemicals associated with metabolic and cardiovascular disease as well as their mechanisms of action is critical for developing novel treatment strategies and public policy to mitigate the impact of these diseases on human health. PMID:24756343

  20. Metabolic consequences of resistive-type exercise

    NASA Technical Reports Server (NTRS)

    Dudley, G. A.

    1988-01-01

    This brief review concerns acute and chronic metabolic responses to resistive-type exercise (RTE) (i.e., Olympic/power weight lifting and bodybuilding). Performance of RTE presents power output substantially greater (10-15-fold) than that evident with endurance-type exercise. Accordingly, RTE relies heavily on the anaerobic enzyme machinery of skeletal muscle for energy supply, with alterations in the rate of aerobic metabolism being modest. Hydrolysis of high energy phosphate compounds (PC, ATP), glycogenolysis, and glycolysis are evident during an acute bout of RTE as indicated by metabolic markers in mixed fiber type skeletal muscle samples. The type of RTE probably influences the magnitude of these responses since the increase in blood lactate is much greater during a typical "bodybuilding" than "power lifting" session. The influence of RTE training on acute metabolic responses to RTE has received little attention. An individual's inherent metabolic characteristics are apparently sufficient to meet the energy demands of RTE as training of this type does not increase VO2max or substantially alter the content of marker enzymes in mixed fiber type skeletal muscle. Analyses of pools of fast- vs slow-twitch fibers, however, indicate that RTE-induced changes may be fiber type specific. Future studies should better delineate the metabolic responses to RTE and determine whether these are related to the enhanced performance associated with such training.

  1. Energy metabolism and metabolic sensors in stem cells: the metabostem crossroads of aging and cancer.

    PubMed

    Menendez, Javier A; Joven, Jorge

    2014-01-01

    We are as old as our adult stem cells are; therefore, stem cell exhaustion is considered a hallmark of aging. Our tumors are as aggressive as the number of cancer stem cells (CSCs) they bear because CSCs can survive treatments with hormones, radiation, chemotherapy, and molecularly targeted drugs, thus increasing the difficulty of curing cancer. Not surprisingly, interest in stem cell research has never been greater among members of the public, politicians, and scientists. But how can we slow the rate at which our adult stem cells decline over our lifetime, reducing the regenerative potential of tissues, while efficiently eliminating the aberrant, life-threatening activity of "selfish", immortal, and migrating CSCs? Frustrated by the gene-centric limitations of conventional approaches to aging diseases, our group and other groups have begun to appreciate that bioenergetic metabolism, i.e., the production of fuel & building blocks for growth and division, and autophagy/mitophagy, i.e., the quality-control, self-cannibalistic system responsible for "cleaning house" and "recycling the trash", can govern the genetic and epigenetic networks that facilitate stem cell behaviors. Indeed, it is reasonable to suggest the existence of a "metabostem" infrastructure that operates as a shared hallmark of aging and cancer, thus making it physiologically plausible to maintain or even increase the functionality of adult stem cells while reducing the incidence of cancer and extending the lifespan. This "metabostemness" property could lead to the discovery of new drugs that reprogram cell metabotypes to increase the structural and functional integrity of adult stem cells and positively influence their lineage determination, while preventing the development and aberrant function of stem cells in cancer tissues. While it is obvious that the antifungal antibiotic rapamycin, the polyphenol resveratrol, and the biguanide metformin already belong to this new family of metabostemness-targeting drugs, we can expect a rapid identification of new drug candidates (e.g., polyphenolic xenohormetins) that reverse or postpone "geroncogenesis", i.e., aging-induced metabolic decline as a driver of tumorigenesis, at the stem cell level. PMID:25038997

  2. Solar heated anaerobic digestor

    Microsoft Academic Search

    Rhoades

    1980-01-01

    A solar heated anaerobic digestor is provided, adapted to utilize organic material capable of decomposing to produce methane gas and a liquid fertilizer. The sealed anaerobic digestor is wrapped with a layer of heat absorptive material followed by a series of abutting removable panels of insulative material. Insulative panels may be temporarily removed to expose the heat absorptive material to

  3. Lactate: the ultimate cerebral oxidative energy substrate?

    Microsoft Academic Search

    Avital Schurr

    2006-01-01

    Research over the past two decades has renewed the interest in lactate, no longer as a useless end product of anaerobic glycolysis in brain (and other tissues), but as an oxidative substrate for energy metabolism. While this topic would be considered blasphemy only three decades ago, much recent evidence indicates that lactate does play a major role in aerobic energy

  4. Upflow anaerobic sludge blanket reactors for treatment of wastewater from the brewery industry

    E-print Network

    Scampini, Amanda C

    2010-01-01

    Anaerobic digestion can be utilized to convert industrial wastewater into clean water and energy. The goal of this project was to set up lab-scale anaerobic digesters to collect data that will be used to develop and validate ...

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

    PubMed Central

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

    2012-01-01

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

  6. Optimizing the anaerobic digestion of microalgae in a coupled Terence Bayen

    E-print Network

    Paris-Sud XI, Université de

    Optimizing the anaerobic digestion of microalgae in a coupled process Terence Bayen , Francis by light and an anaerobic digester. The mathematical model for the dynamics of the reactors takes for sustainable energy production [2]. Anaerobic digestion can be applied to recover the energy stored

  7. Control of metabolic energy by space systems. Part 1: Theoretical reports of space flow structure and function

    Microsoft Academic Search

    B. L Reid; C Bourke

    2003-01-01

    In past papers, a notion emerged that space had elements common to the energy of atomic shells to which it could flow by paths to control metabolic energy of animate systems. This paper examines several authors on the structure and function of space energy wave bundle flows seeking mechanisms for metabolic control. The application of time to these waves provides

  8. Carbon metabolism in legume nodules. Progress report, July 1982-July 1983

    SciTech Connect

    LaRue, T.A.

    1983-01-01

    The goal is to understand how the legume nodule metabolizes carbohydrate to provide energy and reductant for symbiotic fixation. The working hypothesis has been that the plant cytosol is microacrobic and that some carbon metabolism may be via anaerobic pathways similar to those in roots of flood tolerant plants. A method of analyzing redox changes in intact mitochondria, bacteroids or bacteria was adapted; a method of manipulating nitrogenase activity by oxygen inhibition was developed; the production of alcohol by soybean nodules was studied; and enzymes metabolizing alcohol/aldehyde were found in other nitrogen fixing systems. (ACR)

  9. METABOLIC UTILIZATION OF ENERGY AND MAINTENANCE REQUIREMENTS IN LACTATING SOWS

    Microsoft Academic Search

    J. Noblet; M. Etienne

    2010-01-01

    Metabolizable energy (ME), heat production (measured by indirect calorimetry in respiration chambers), milk energy output and body energy mobilization were measured in 20 gilts (10 repli- cates of two littermates) during a 21-d lactation. Two energy levels were used: 14.2 and 10.4 Meal ME.d -l .sow -1 in the high energy (HE) and low energy (LE) groups, respectively. The daily

  10. Anaerobic Benzene Oxidation by Geobacter Species

    PubMed Central

    Bain, Timothy S.; Nevin, Kelly P.; Barlett, Melissa A.; Lovley, Derek R.

    2012-01-01

    The abundance of Geobacter species in contaminated aquifers in which benzene is anaerobically degraded has led to the suggestion that some Geobacter species might be capable of anaerobic benzene degradation, but this has never been documented. A strain of Geobacter, designated strain Ben, was isolated from sediments from the Fe(III)-reducing zone of a petroleum-contaminated aquifer in which there was significant capacity for anaerobic benzene oxidation. Strain Ben grew in a medium with benzene as the sole electron donor and Fe(III) oxide as the sole electron acceptor. Furthermore, additional evaluation of Geobacter metallireducens demonstrated that it could also grow in benzene-Fe(III) medium. In both strain Ben and G. metallireducens the stoichiometry of benzene metabolism and Fe(III) reduction was consistent with the oxidation of benzene to carbon dioxide with Fe(III) serving as the sole electron acceptor. With benzene as the electron donor, and Fe(III) oxide (strain Ben) or Fe(III) citrate (G. metallireducens) as the electron acceptor, the cell yields of strain Ben and G. metallireducens were 3.2 × 109 and 8.4 × 109 cells/mmol of Fe(III) reduced, respectively. Strain Ben also oxidized benzene with anthraquinone-2,6-disulfonate (AQDS) as the sole electron acceptor with cell yields of 5.9 × 109 cells/mmol of AQDS reduced. Strain Ben serves as model organism for the study of anaerobic benzene metabolism in petroleum-contaminated aquifers, and G. metallireducens is the first anaerobic benzene-degrading organism that can be genetically manipulated. PMID:23001648

  11. Intraspecific variation in aerobic and anaerobic locomotion: gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata) do not exhibit a trade-off between maximum sustained swimming speed and minimum cost of transport.

    PubMed

    Svendsen, Jon C; Tirsgaard, Bjørn; Cordero, Gerardo A; Steffensen, John F

    2015-01-01

    Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; U crit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3) there is a trade-off between maximum sustained swimming speed (U sus) and minimum cost of transport (COTmin); and (4) variation in U sus correlates positively with optimum swimming speed (U opt; i.e., the speed that minimizes energy expenditure per unit of distance traveled). Data collection involved swimming respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg(-1). Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer, suggesting that the metabolic cost of burst swimming is similar across various types of locomotion. There was no correlation between U crit and MS or anaerobic capacity in S. aurata indicating that other factors, including morphological or biomechanical traits, influenced U crit. We found no evidence of a trade-off between U sus and COTmin. In fact, data revealed significant negative correlations between U sus and COTmin, suggesting that individuals with high U sus also exhibit low COTmin. Finally, there were positive correlations between U sus and U opt. Our study demonstrates the energetic importance of anaerobic metabolism during unsteady swimming, and provides intraspecific evidence that superior maximum sustained swimming speed is associated with superior swimming economy and optimum speed. PMID:25741285

  12. Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and Xylene Compounds by Dechloromonas Strain RCB

    Microsoft Academic Search

    Romy Chakraborty; Susan M. O'Connor; Emily Chan; John D. Coates

    2005-01-01

    Dechloromonas strain RCB has been shown to be capable of anaerobic degradation of benzene coupled to nitrate reduction. As a continuation of these studies, the metabolic versatility and hydrocarbon biodegradative capability of this organism were investigated. The results of these revealed that in addition to nitrate, strain RCB could alternatively degrade benzene both aerobically and anaerobically with perchlorate or chlorate

  13. The role of redox balances in the anaerobic fermentation of xylose by yeasts

    Microsoft Academic Search

    Peter M. Bruinenberg; Peter H. M. Bot; Johannes P. Dijken; W. Alexander Scheffers

    1983-01-01

    The kinetics of glucose and xylose utilization by batch cultures of Candida utilis were studied under aerobic and anaerobic conditions during growth in complex media. Rapid ethanol formation occurred during growth on glucose when aerobic cultures were shifted to anaerobic conditions. However, with xylose as a substrate, transfer to anaerobiosis resulted in an immediate cessation of metabolic activity, as evidenced

  14. Glycolysis in Wonderland: The Importance of Energy Dissipation in Metabolic Pathways

    NASA Astrophysics Data System (ADS)

    Aledo, J. Carlos; Esteban Del Valle, Alicia

    2002-11-01

    Staying alive is an energetically expensive task. Therefore, the necessity of coupling the exergonic nutrient transformation reactions to the endergonic synthesis of ATP is easily grasped by most undergraduate students. On the other hand, it is often difficult for students to understand the importance of energy dissipation. The purpose of this paper is to illustrate that energy dissipation fulfils an important role in metabolism, driving the flow of matter throughout the metabolic pathways, avoiding, in this way, the chemical equilibrium which in biology is a synonym of death. In this paper we propose a teaching approach where a blending of science and science fiction will lead us to the desired conclusions.

  15. Comparison Between Cerebral Tissue Oxygen Tension and Energy Metabolism in Experimental Subdural Hematoma

    Microsoft Academic Search

    Troels Halfeld Nielsen; Susanne I. Engell; Rikke Aagaard Johnsen; Mette K. Schulz; Oke Gerke; Jacob Hjelmborg; Palle Toft; Carl-Henrik Nordström

    Background  An experimental swine model (n = 7) simulating an acute subdural hematoma (ASDH) was employed (1) to explore the relation between the brain tissue oxygenation\\u000a (PbtO2) and the regional cerebral energy metabolism as obtained by microdialysis, and (2) to define the lowest level of PbtO2 compatible with intact energy metabolism.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  ASDH was produced by infusion of 7 ml of autologous blood (infusion rate

  16. Mitochondrial biogenesis and energy production in differentiating murine stem cells: a functional metabolic study.

    PubMed

    Han, Sungwon; Auger, Christopher; Thomas, Sean C; Beites, Crestina L; Appanna, Vasu D

    2014-02-01

    The significance of metabolic networks in guiding the fate of the stem cell differentiation is only beginning to emerge. Oxidative metabolism has been suggested to play a major role during this process. Therefore, it is critical to understand the underlying mechanisms of metabolic alterations occurring in stem cells to manipulate the ultimate outcome of these pluripotent cells. Here, using P19 murine embryonal carcinoma cells as a model system, the role of mitochondrial biogenesis and the modulation of metabolic networks during dimethyl sulfoxide (DMSO)-induced differentiation are revealed. Blue native polyacrylamide gel electrophoresis (BN-PAGE) technology aided in profiling key enzymes, such as hexokinase (HK) [EC 2.7.1.1], glucose-6-phosphate isomerase (GPI) [EC 5.3.1.9], pyruvate kinase (PK) [EC 2.7.1.40], Complex I [EC 1.6.5.3], and Complex IV [EC 1.9.3.1], that are involved in the energy budget of the differentiated cells. Mitochondrial adenosine triphosphate (ATP) production was shown to be increased in DMSO-treated cells upon exposure to the tricarboxylic acid (TCA) cycle substrates, such as succinate and malate. The increased mitochondrial activity and biogenesis were further confirmed by immunofluorescence microscopy. Collectively, the results indicate that oxidative energy metabolism and mitochondrial biogenesis were sharply upregulated in DMSO-differentiated P19 cells. This functional metabolic and proteomic study provides further evidence that modulation of mitochondrial energy metabolism is a pivotal component of the cellular differentiation process and may dictate the final destiny of stem cells. PMID:24350892

  17. New ways of defining protein and energy relationships in inborn errors of metabolism.

    PubMed

    Humphrey, Maureen; Truby, Helen; Boneh, Avihu

    2014-08-01

    Dietary restrictions required to manage individuals with inborn errors of metabolism (IEM) are essential for metabolic control, however may result in an increased risk to both short and long-term nutritional status. Dietary factors most likely to influence nutritional status include energy intake, protein quality and quantity, micronutrient intake and the frequency and extent to which the diet must be altered during periods of increased physical or metabolic stress. Patients on the most restrictive diets, including those with intakes consisting of low levels of natural protein or those with recurrent illness or frequent metabolic decompensation carry the most nutritional risk. Due to the difficulties in determining condition specific requirements, dietary intake recommendations and nutritional monitoring tools used in patients with IEM are the same as, or extrapolated from, those used in healthy populations. As a consequence, evidence is lacking for the safest dietary prescriptions required to manage these patients long term, as tolerance to dietary therapy is generally described in terms of metabolic stability rather than long term nutritional and health outcomes. As the most frequent therapeutic dietary manipulation in IEM is alteration in dietary protein, and as protein status is critically dependent on adequate energy provision, the use of a Protein to Energy ratio (P:E ratio) as an additional tool will better define the relationship between these critical components. This could accurately define dietary quality and ensure that not only an adequate, but also a safe and balanced intake is provided. PMID:24916709

  18. CceR and AkgR Regulate Central Carbon and Energy Metabolism in Alphaproteobacteria

    PubMed Central

    Imam, Saheed; Noguera, Daniel R.

    2015-01-01

    ABSTRACT? Many pathways of carbon and energy metabolism are conserved across the phylogeny, but the networks that regulate their expression or activity often vary considerably among organisms. In this work, we show that two previously uncharacterized transcription factors (TFs) are direct regulators of genes encoding enzymes of central carbon and energy metabolism in the alphaproteobacterium Rhodobacter sphaeroides. The LacI family member CceR (RSP_1663) directly represses genes encoding enzymes in the Entner-Doudoroff pathway, while activating those encoding the F1F0 ATPase and enzymes of the tricarboxylic acid (TCA) cycle and gluconeogenesis, providing a direct transcriptional network connection between carbon and energy metabolism. We identified bases that are important for CceR DNA binding and showed that DNA binding by this TF is inhibited by 6-phosphogluconate. We also showed that the GntR family TF AkgR (RSP_0981) directly activates genes encoding several TCA cycle enzymes, and we identified conditions where its activity is increased. The properties of single and double ?CceR and ?AkgR mutants illustrate that these 2 TFs cooperatively regulate carbon and energy metabolism. Comparative genomic analysis indicates that CceR and AkgR orthologs are found in other alphaproteobacteria, where they are predicted to have a conserved function in regulating central carbon metabolism. Our characterization of CceR and AkgR has provided important new insight into the networks that control central carbon and energy metabolism in alphaproteobacteria that can be exploited to modify or engineer new traits in these widespread and versatile bacteria. PMID:25650399

  19. FoxO1, the Transcriptional Chief of Staff of Energy Metabolism

    PubMed Central

    Kousteni, Stavroula

    2011-01-01

    FoxO1, one of the four FoxO isoforms of Forkhead transcription factors, is highly expressed in insulin-responsive tissues, including pancreas, liver, skeletal muscle and adipose tissue, as well as in the skeleton. In all these tissues FoxO1 orchestrates the transcriptional cascades regulating glucose metabolism. Indeed, FoxO1 is a major target of insulin which inhibits its transcriptional activity via nuclear exclusion. In the pancreas, FoxO1 regulates ?-cell formation and function by a balanced dual mode of action that suppresses ?-cell proliferation but promotes survival. Hepatic glucose production is promoted and lipid metabolism is regulated by FoxO1 such that under insulin resistance they lead to hyperglycemia and dyslipidemia, two features of type 2 diabetes. In skeletal muscle FoxO1 maintains energy homeostasis during fasting and provides energy supply through breakdown of carbohydrates, a process that leads to atrophy and underlies glycemic control in insulin resistance. In a dual function, FoxO1 regulates energy and nutrient homeostasis though energy storage in white adipose tissue, but promotes energy expenditure in brown adipose tissue. In its most recently discovered novel role, FoxO1 acts as a transcriptional link between the skeleton and pancreas as well as other insulin target tissues to regulate energy homeostasis. Through its expression in osteoblasts it controls glucose metabolism, insulin sensitivity and energy expenditure. In a feedback mode of regulation, FoxO1 is also a target of insulin signaling in osteoblasts. Insulin suppresses activity of osteoblastic FoxO1 thus promoting beneficial effects of osteoblasts on glucose metabolism. The multiple actions of FoxO1 in all glucose-regulating organs, along with clinical studies suggesting that its glycemic properties are conserved in humans, establish this transcription factor as a master regulator of energy metabolism across species. PMID:21816244

  20. Emergy-based energy and material metabolism of the Yellow River basin

    NASA Astrophysics Data System (ADS)

    Chen, B.; Chen, G. Q.

    2009-03-01

    The Yellow River basin is an opening ecosystem exchanging energy and materials with the surrounding environment. Based on emergy as embodied solar energy, the social energy and materials metabolism of the Yellow River basin is aggregated into emergetic equivalent to assess the level of resource depletion, environmental impact and local sustainability. A set of emergy indices are also established to manifest the ecological status of the total river basin ecosystem.

  1. Role of Energy Metabolism in the Brown Fat Gene Program

    PubMed Central

    Nam, Minwoo; Cooper, Marcus P.

    2015-01-01

    In murine and human brown adipose tissue (BAT), mitochondria are powerful generators of heat that safely metabolize fat, a feature that has great promise in the fight against obesity and diabetes. Recent studies suggest that the actions of mitochondria extend beyond their conventional role as generators of heat. There is mounting evidence that impaired mitochondrial respiratory capacity is accompanied by attenuated expression of Ucp1 and other BAT-selective genes, implying that mitochondria exert transcriptional control over the brown fat gene program. In this review, we discuss the current understanding of brown fat mitochondria, their potential role in transcriptional control of the brown fat gene program, and potential strategies to treat obesity in humans by leveraging thermogenesis in brown adipocytes. PMID:26175716

  2. Adipose tissue lipolysis and energy metabolism in early cancer cachexia in mice.

    PubMed

    Kliewer, Kara L; Ke, Jia-Yu; Tian, Min; Cole, Rachel M; Andridge, Rebecca R; Belury, Martha A

    2015-06-01

    Cancer cachexia is a progressive metabolic disorder that results in depletion of adipose tissue and skeletal muscle. A growing body of literature suggests that maintaining adipose tissue mass in cachexia may improve quality-of-life and survival outcomes. Studies of lipid metabolism in cachexia, however, have generally focused on later stages of the disorder when severe loss of adipose tissue has already occurred. Here, we investigated lipid metabolism in adipose, liver and muscle tissues during early stage cachexia - before severe fat loss - in the colon-26 murine model of cachexia. White adipose tissue mass in cachectic mice was moderately reduced (34-42%) and weight loss was less than 10% of initial body weight in this study of early cachexia. In white adipose depots of cachectic mice, we found evidence of enhanced protein kinase A - activated lipolysis which coincided with elevated total energy expenditure and increased expression of markers of brown (but not white) adipose tissue thermogenesis and the acute phase response. Total lipids in liver and muscle were unchanged in early cachexia while markers of fatty oxidation were increased. Many of these initial metabolic responses contrast with reports of lipid metabolism in later stages of cachexia. Our observations suggest intervention studies to preserve fat mass in cachexia should be tailored to the stage of cachexia. Our observations also highlight a need for studies that delineate the contribution of cachexia stage and animal model to altered lipid metabolism in cancer cachexia and identify those that most closely mimic the human condition. PMID:25457061

  3. Interferon gamma (IFN-?) disrupts energy expenditure and metabolic homeostasis by suppressing SIRT1 transcription

    PubMed Central

    Li, Ping; Zhao, Yuhao; Wu, Xiaoyan; Xia, Minjie; Fang, Mingming; Iwasaki, Yasumasa; Sha, Jiahao; Chen, Qi; Xu, Yong; Shen, Aiguo

    2012-01-01

    Chronic inflammation impairs metabolic homeostasis and is intimately correlated with the pathogenesis of type 2 diabetes. The pro-inflammatory cytokine IFN-? is an integral part of the metabolic inflammation circuit and contributes significantly to metabolic dysfunction. The underlying mechanism, however, remains largely unknown. In the present study, we report that IFN-? disrupts the expression of genes key to cellular metabolism and energy expenditure by repressing the expression and activity of SIRT1 at the transcription level. Further analysis reveals that IFN-? requires class II transactivator (CIITA) to repress SIRT1 transcription. CIITA, once induced by IFN-?, is recruited to the SIRT1 promoter by hypermethylated in cancer 1 (HIC1) and promotes down-regulation of SIRT1 transcription via active deacetylation of core histones surrounding the SIRT1 proximal promoter. Silencing CIITA or HIC1 restores SIRT1 activity and expression of metabolic genes in skeletal muscle cells challenged with IFN-?. Therefore, our data delineate an IFN-?/HIC1/CIITA axis that contributes to metabolic dysfunction by suppressing SIRT1 transcription in skeletal muscle cells and as such shed new light on the development of novel therapeutic strategies against type 2 diabetes. PMID:22064865

  4. Human longevity is characterised by high thyroid stimulating hormone secretion without altered energy metabolism.

    PubMed

    Jansen, S W; Akintola, A A; Roelfsema, F; van der Spoel, E; Cobbaert, C M; Ballieux, B E; Egri, P; Kvarta-Papp, Z; Gereben, B; Fekete, C; Slagboom, P E; van der Grond, J; Demeneix, B A; Pijl, H; Westendorp, R G J; van Heemst, D

    2015-01-01

    Few studies have included subjects with the propensity to reach old age in good health, with the aim to disentangle mechanisms contributing to staying healthier for longer. The hypothalamic-pituitary-thyroid (HPT) axis maintains circulating levels of thyroid stimulating hormone (TSH) and thyroid hormone (TH) in an inverse relationship. Greater longevity has been associated with higher TSH and lower TH levels, but mechanisms underlying TSH/TH differences and longevity remain unknown. The HPT axis plays a pivotal role in growth, development and energy metabolism. We report that offspring of nonagenarians with at least one nonagenarian sibling have increased TSH secretion but similar bioactivity of TSH and similar TH levels compared to controls. Healthy offspring and spousal controls had similar resting metabolic rate and core body temperature. We propose that pleiotropic effects of the HPT axis may favour longevity without altering energy metabolism. PMID:26089239

  5. Human longevity is characterised by high thyroid stimulating hormone secretion without altered energy metabolism

    PubMed Central

    Jansen, S. W.; Akintola, A. A.; Roelfsema, F.; van der Spoel, E.; Cobbaert, C. M.; Ballieux, B. E.; Egri, P.; Kvarta-Papp, Z.; Gereben, B.; Fekete, C.; Slagboom, P. E.; van der Grond, J.; Demeneix, B. A.; Pijl, H.; Westendorp, R. G. J.; van Heemst, D.

    2015-01-01

    Few studies have included subjects with the propensity to reach old age in good health, with the aim to disentangle mechanisms contributing to staying healthier for longer. The hypothalamic-pituitary-thyroid (HPT) axis maintains circulating levels of thyroid stimulating hormone (TSH) and thyroid hormone (TH) in an inverse relationship. Greater longevity has been associated with higher TSH and lower TH levels, but mechanisms underlying TSH/TH differences and longevity remain unknown. The HPT axis plays a pivotal role in growth, development and energy metabolism. We report that offspring of nonagenarians with at least one nonagenarian sibling have increased TSH secretion but similar bioactivity of TSH and similar TH levels compared to controls. Healthy offspring and spousal controls had similar resting metabolic rate and core body temperature. We propose that pleiotropic effects of the HPT axis may favour longevity without altering energy metabolism. PMID:26089239

  6. Evidence for a relationship between body mass and energy metabolism in the human brain

    PubMed Central

    Schmoller, André; Hass, Torben; Strugovshchikova, Olga; Melchert, Uwe H; Scholand-Engler, Harald G; Peters, Achim; Schweiger, Ulrich; Hohagen, Fritz; Oltmanns, Kerstin M

    2010-01-01

    Cerebral energy metabolism has been suggested to have an important function in body weight regulation. We therefore examined whether there is a relationship between body mass and adenosine triphosphate (ATP) metabolism in the human brain. On the basis of our earlier findings indicating a neuroprotective preferential energy supply of the brain, as compared with peripheral muscle on experimentally induced hypoglycemia, we examined whether this physiological response is preserved also in low-weight and obese participants. We included 45 healthy male subjects with a body mass index (BMI) ranging from 17 to 44?kg/m2. Each participant underwent a hypoglycemic glucose-clamp intervention, and the ATP metabolism, that is, the content of high-energy phosphates phosphocreatine (PCr) and ATP, was measured repeatedly by 31phosphor magnetic resonance spectroscopy (31P-MRS) in the cerebral cortex and skeletal muscle. Results show an inverse correlation between BMI and high-energy phosphate content in the brain (P<0.01), whereas there was no such relationship found between skeletal muscle and BMI. The hypoglycemic clamp intervention did not affect the ATP metabolism in both tissues. Our data show an inverse correlation between BMI and cerebral high-energy phosphate content in healthy humans, suggesting a close relationship between energetic supply of the brain and body weight regulation. PMID:20389303

  7. Anaerobic wastewater treatment: Final report

    SciTech Connect

    Suidan, M.T.; Pfeffer, J.T.; Nakhla, G.F.; Fraser, J.; Klepp, B.E.; Mueller, P.A.

    1987-11-01

    This project was undertaken to evaluate the effects of wastewater dilution, GAC (granular activated carbon) replacement rate, GAC particle size, operating temperature, and reactor configuration on the treatment of coal gasification wastewater with the expanded-bed GAC anaerobic bioreactor. Coal gasification wastewater used was generated in a low BTU, elevated pressure, stirred fixed-bed, gasifier operated by Morgantown Energy Technology Center (METC) in Morgantown, West Virginia. The treatability of another wastewater generated in a full-scale, slagging fixed-bed modification of a conventional dry-ash, pressurized gasifier located at the Great Plains gasification Association (GPGA) facility in North Dakota was also evaluated. Full-strength METC wastewater was found to be effectively treated at chemical oxygen demand (COD) loading rates as high as 19.4 g/kg GAC-day. At this rate, an excess of 50% of the applied COD was converted to methane, and a carbon utilization rate of 10 g GAC per liter of wastewater treated was employed. At these operating conditions, COD removal efficiencies across the treatment system exceeded 95%. Good COD removal and efficient COD conversion to methane were attainable at loading rates exceeding 70 g COD/kg GAC-day. Wastewater generated at the GPGA facility was found to be treatable at full-strength in the expanded-bed GAC anaerobic reactor at COD loading rates as high as 48 g COD/kg GAC-day. COD removal efficiencies at this loading rate exceeded 90%. Coal gasification wastewater was found to resist treatment under thermophilic anaerobic conditions. The thermophilic expanded-bed GAC anaerobic reactor affected very poor conversion efficiencies of phenol, even when fed a synthetically prepared phenol bearing wastewater. 29 refs., 77 figs., 16 tabs.

  8. Cultivation of anaerobic and facultatively anaerobic bacteria from spacecraft-associated clean rooms.

    PubMed

    Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

    2009-06-01

    In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus. PMID:19363082

  9. Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms?

    PubMed Central

    Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

    2009-01-01

    In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus. PMID:19363082

  10. Does low daily energy expenditure drive low metabolic capacity in the tropical robin, Turdus grayi?

    PubMed

    Wagner, Dominique N; Mineo, Patrick M; Sgueo, Carrie; Wikelski, Martin; Schaeffer, Paul J

    2013-08-01

    Temperate and tropical birds possess divergent life history strategies. Physiological parameters including energy metabolism correlate with the life history such that tropical species with a slower 'pace of life' have lower resting and maximal metabolic rates than temperate congeners. To better understand the physiological mechanisms underlying these differences, we investigated the relationship of metabolic capacity, muscle oxidative capacity and activity patterns to variation in life history patterns in American robins (Turdus migratorius), while resident in central North America and Clay-colored robins (Turdus grayi) resident in Panama. We measured summit metabolism [Formula: see text] in birds from both tropical and temperate habitats and found that the temperate robins have a 60 % higher metabolic capacity. We also measured the field metabolic rate (FMR) of free-living birds using heart rate (HR) telemetry and found that temperate robins' daily energy expenditure was also 60 % higher. Thus, [Formula: see text] and FMR both reflect life history differences between the species. Further, both species operate at a nearly identical ~50 % of their thermogenic capacity throughout a given day. As a potential mechanism to explain differences in activity and metabolic capacity, we ask whether oxidative properties of flight muscle are altered in accordance with life history variation and found minimal differences in oxidative capacity of skeletal muscle. These data demonstrate a close relationship between thermogenic capacity and daily activity in free-living birds. Further, they suggest that the slow pace of life in tropical birds may be related to the maintenance of low activity rather than functional capacity of the muscle tissue. PMID:23456167

  11. Economic viability of phytoremediation of a cadmium contaminated agricultural area using energy maize. Part II: economics of anaerobic digestion of metal contaminated maize in Belgium.

    PubMed

    Thewys, T; Witters, N; Meers, E; Vangronsveld, J

    2010-09-01

    This paper deals with remediation of the Campine soil, an agricultural area diffusely contaminated with metals where most farmers raise dairy cattle and grow fodder maize. In a previous study, we calculated the effect of switching from fodder to energy maize on the farmer's income. Selling this energy maize as feedstock for anaerobic digestion to produce renewable energy could lead to a significant increase in his income. This paper explores the economic opportunities for the farmer of digesting the harvested contaminated biomass himself, by performing a Net Present Value (NPV) analysis on the digestion activity and by calculating the probability of a positive NPV of income resulting from the digestion installation. We investigate the trade off between the maximum price for energy maize that can be paid by the digestion activity and the minimum price that the farming activity needs to compensate for covering its production costs. Integrating the previous study in the current analysis results in an increase of total extra income for the farmer (i.e., from both growing energy maize and performing digestion). PMID:21166275

  12. Xylan degradation by the anaerobic bacterium Bacteroides xylanolyticus

    Microsoft Academic Search

    P. J. Y. M. J. Schyns

    1997-01-01

    Plant cell walls are the major reservoir of fixed carbon in nature. The mineralization of the fiber material, the so called lignocellulosic complex, proceeds almost exclusively by microbial processes in both aerobic and anaerobic environments. In anaerobic microbial processes the energy of the plant polymers can be conserved in fermentation products. The valorization of agricultural waste plant materials can consist

  13. Balancing hygienization and anaerobic digestion of raw sewage sludge.

    PubMed

    Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

    2012-12-01

    The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery. PMID:23063441

  14. Bioreactor performance in anaerobic digestion of fruit and vegetable wastes

    Microsoft Academic Search

    H. Bouallagui; Y. Touhami; R. Ben Cheikh; M. Hamdi

    2005-01-01

    This work reviews the potential of anaerobic digestion for material recovery and energy production from fruit and vegetable wastes (FVW). These wastes contain 8–18% total solids (TS), with a total volatile solids (VS) content of 86–92%. The organic fraction includes about 75% easy biodegradable matter (sugars and hemicellulose), 9% cellulose and 5% lignin. Anaerobic digestion of FVW was studied under

  15. Anaerobic digestion of organic solid poultry slaughterhouse waste – a review

    Microsoft Academic Search

    E. Salminen; J. Rintala

    2002-01-01

    This work reviews the potential of anaerobic digestion for material recovery and energy production from poultry slaughtering by-products and wastes. First, we describe and quantify organic solid by-products and wastes produced in poultry farming and poultry slaughterhouses and discuss their recovery and disposal options. Then we review certain fundamental aspects of anaerobic digestion considered important for the digestion of solid

  16. Comparison of Aerobic and Anaerobic Biodegradation of Sugarcane Vinasse.

    PubMed

    Mota, V T; Araújo, T A; Amaral, M C S

    2015-07-01

    Vinasse is the main liquid waste from ethanol production, and it has a considerable pollution potential. Biological treatment is a promising alternative to reduce its organic load. The aim of this study was to analyze the biodegradation of sugarcane juice vinasse in aerobic and anaerobic conditions. The content of carbohydrates, proteins and volatile fatty acids was evaluated. Vinasse samples showed a high biodegradability (>96.5 %) and low percentage of inert chemical oxygen demand (COD) (<3.2 %) in both aerobic and anaerobic conditions. The rates of substrate utilization were slightly higher in aerobic reactors, but COD stabilization occurred simultaneously in the anaerobic reactors, confirming its suitability for anaerobic digestion. Inert COD in anaerobic conditions was lower than in aerobic conditions. On the other hand, COD from metabolic products in the anaerobic reactors was higher than in the aerobic ones, indicating an increased release of soluble microbial products (SMPs) by anaerobic microorganisms. The results indicated that carbohydrates were satisfactorily degraded and protein-like substances were the major components remaining after biological degradation of vinasse. PMID:25957273

  17. EFFECTS OF CONTINUOUS-WAVE, PULSED, AND SINUSOIDAL-AMPLITUDE-MODULATED MICROWAVES ON BRAIN ENERGY METABOLISM

    EPA Science Inventory

    A comparison of the effects of continuous wave, sinusoidal-amplitude modulated, and pulsed square-wave-modulated 591-MHz microwave exposures on brain energy metabolism was made in male Sprague Dawley rats (175-225g). Brain NADH fluorescence, adensine triphosphate (ATP) concentrat...

  18. Energy metabolism, proteotoxic stress and age-related dysfunction – Protection by carnosine

    Microsoft Academic Search

    Alan R. Hipkiss

    This review will discuss the relationship between energy metabolism, protein dysfunction and the causation and modulation of age-related proteotoxicity and disease. It is proposed that excessive glycolysis, rather than aerobic (mitochondrial) activity, could be causal to proteotoxic stress and age-related pathology, due to the generation of endogenous glycating metabolites: the deleterious role of methylglyoxal (MG) is emphasized. It is suggested

  19. Effects of Hydrostatic Pressure on Energy Metabolism and Osmoregulation in Crab and Fish

    Microsoft Academic Search

    P Sébert; B Simon; A Péqueux

    1997-01-01

    This review will focus on the effects of hydrostatic pressure on the oxidative metabolism and on the energy production of the eel Anguilla anguilla, in comparison with the results of investigations conducted on the other powerful euryhaline species, the chinese crab Eriocheir sinensis. Anguilla and Eriocheir were chosen as being both aquatic ectotherms with comparable life modes, the eel being

  20. Cornuside Attenuates Apoptosis and Ameliorates Mitochondrial Energy Metabolism in Rat Cortical Neurons

    Microsoft Academic Search

    Wang-Lin Jiang; Xi-Guang Chen; Hai-Bo Zhu; Jian Hou; Jing-Wei Tian

    2009-01-01

    Cornuside, a secoiridoid glucoside compound, was isolated from the fruit of Cornus officinalis Sieb. et Zucc. The present study elucidates the effects of cornuside on cultured rat cortical neuron damage induced by oxygen-glucose deprivation. The results show that cornuside treatment obviously attenuates apoptosis and ameliorates mitochondrial energy metabolism in rat cortical neurons by increasing the cell survival rate, mitochondrial antioxidant

  1. Greenhouse gas production: A comparison between aerobic and anaerobic wastewater treatment technology

    Microsoft Academic Search

    F. Y. Cakir; M. K. Stenstrom

    2005-01-01

    Anaerobic wastewater treatment offers improved energy conservation with potential reduction in greenhouse gas emissions. Pitfalls exist in that the methane produced in anaerobic treatment can offset any reductions in carbon dioxide emissions, if it is released to the environment. This paper analyzes greenhouse gas emissions from both aerobic and anaerobic treatment systems, including sludge digestion and the losses of dissolved

  2. EVALUATION OF THE PERFORMANCE OF DIFFERENT ANAEROBIC DIGESTION TECHNOLOGIES FOR SOLID WASTE TREATMENT

    Microsoft Academic Search

    Mariana Chavez-Vazquez; David M. Bagley

    The anaerobic digestion of solid wastes is now a widely- used technology in Europe with more than 50 full- scale plants operating. However, anaerobic solid waste digestion is still used to only a limited extent in North America with only three facilities in Canada. Because of the expected importance of anaerobic digestion in the future for energy recovery, reliable tools

  3. The role of natural wood constituents on the anaerobic treatability of forest industry wastewaters

    Microsoft Academic Search

    R. Sierra-Alvarez

    1990-01-01

    Anaerobic treatment has been shown to be an efficient and energy conserving method for treating various types of readily biodegradable non-inhibitory forest industry wastewaters. However, the high toxicity of paper mill effluents derived from chemical wood processing operations has hampered the wide spread application of anaerobic treatment in the forest industry.This dissertation describes research on the anaerobic treatment of inhibitory

  4. Energy metabolism in brain cells: effects of elevated ammonia concentrations.

    PubMed

    Hertz, Leif; Kala, Geeta

    2007-12-01

    Both neurons and astrocytes have high rates of glucose utilization and oxidative metabolism. Fully 20% of glucose consumption is used for astrocytic production of glutamate and glutamine, which during intense glutamatergic activity leads to an increase in glutamate content, but at steady state is compensated for by an equally intense oxidation of glutamate. The amounts of ammonia used for glutamine synthesis and liberated during glutamine hydrolysis are large, compared to the additional demand for glutamine synthesis in hyperammonemic animals and patients with hepatic encephalopathy. Nevertheless, elevated ammonia concentrations lead to an increased astrocytic glutamine production and an elevated content of glutamine combined with a decrease in glutamate content, probably mainly in a cytosolic pool needed for normal activity of the malate-asparate shuttle (MAS); another compartment generated by glutamine hydrolysis is increased. As a result of reduced MAS activity the pyruvate/lactate ratio is decreased in astrocytes but not in neurons and decarboxylation of pyruvate to form acetyl coenzyme A is reduced. Elevated ammonia concentrations also inhibit decarboxylation of alpha-ketoglutarate in the TCA cycle. This effect occurs in both neurons and astrocytes, is unrelated to MAS activity and seen after chronic treatment with ammonia even in the absence of elevated ammonia concentrations. PMID:17882538

  5. Construction and use of a direct calorimeter to estimate energy expenditure in hibernators

    Microsoft Academic Search

    Mark S. Burger; Frank van Breukelen

    2011-01-01

    Metabolic rates have traditionally been estimated through indirect calorimetry (gas exchange or respirometry) due to its ease and availability. Oxygen consumption neglects the contributions of anaerobic metabolism, while direct calorimetry (heat production) estimates both anaerobic and aerobic metabolism. Walsberg and Hoffman (2005) report anaerobic metabolism may be more important to small rodents than was previously thought. During the non-steady state

  6. The contributionof the large intestine to energy supplies in man1'2

    Microsoft Academic Search

    NI McNeil

    1984-01-01

    Herbivores obtain a considerable proportion of energy requirements from carbohydrate by the chain of anaerobic carbohydrate fermentation producing short-chain fatty acids that are absorbed then metabolized. The evidence for this sequence occurring in the large intestine of man is reviewed and estimated to produce 5 to 10% of human energy requirements. Further small amounts of energy may come from large

  7. Changes in energy metabolism after induction therapy in patients with severe or moderate ulcerative colitis

    PubMed Central

    Inoue, Mai; Sasaki, Masaya; Takaoka, Azusa; Kurihara, Mika; Iwakawa, Hiromi; Bamba, Shigeki; Ban, Hiromitsu; Andoh, Akira

    2015-01-01

    We investigated the changes in energy expenditure during induction therapy in patients with severe or moderate ulcerative colitis. Thirteen patients (10 men, 3 women; mean age, 36.5 years) with ulcerative colitis admitted to the Shiga University Hospital were enrolled in this study. We measured the resting energy expenditure and respiratory quotients of these patients before and after induction therapy with indirect calorimetry. We analyzed the changes of nutritional status and serum inflammatory cytokine levels and also evaluated the relationship between energy metabolism and disease activity by using the Seo index and Lichtiger index. The resting energy expenditure was 26.3 ± 3.8 kcal/kg/day in the active stage and significantly decreased to 23.5 ± 2.4 kcal/kg/day after induction therapy (p<0.01). The resting energy expenditure changed in parallel with the disease activity index and C-reactive protein and inflammatory cytokine levels. The respiratory quotient significantly increased after induction therapy. Thus, moderate to severe ulcerative colitis patients had a hyper-metabolic status, and the energy metabolism of these patients significantly changed after induction therapy. Therefore, we recommend that nutritional management with 30–34 kcal/kg/day (calculated as measured resting energy expenditure × activity factor, 1.3) may be optimal for hospitalized ulcerative colitis patients. PMID:26060352

  8. ANAEROBIC SOIL DISINFESTATION IN MICROCOSMS OF TWO SANDY SOILS.

    PubMed

    Stremi?ska, M A; Runia, W T; Termorshuizen, A J; Feil, H; Van Der Wurff, A W G

    2014-01-01

    In recent years, anaerobic soil disinfestation (ASD) has been proposed as an alternative control method of soil-borne plant pathogens. It involves adding a labile carbon source, irrigating the soil to stimulate decomposition of organic material and then covering the soil with air-tight plastic to limit gas exchange. During the ASD process, soil microorganisms switch from aerobic to anaerobic metabolism. As a result, by-products of anaerobic metabolism are released into the soil environment such as various organic acids and gases. These by-products are reported to have a negative effect on survival of soil-borne plant pathogens. However, the efficacy of ASD to reduce soil-borne pathogens in practice may vary significantly. Therefore, we studied the efficacy of the ASD process in two different soils. In addition, it was investigated whether a pre-treatment with an anaerobic bacterial inoculum prior to ASD affected the efficacy of the process. Two sandy soils (dune sand and glacial sand) were inoculated in 2 L soil microcosms. We tested the efficacy of ASD treatment against the potato cyst nematode Globodera pallida. For each soil, three treatments were used: control treatment (no Herbie addition, aerobic incubation), ASD 1 (organic substrate addition, anaerobic incubation) and ASD 2 (organic substrate and anaerobic bacterial inoculum addition, anaerobic incubation). Soil microcosms were incubated in the dark at 20°C for two weeks. We observed that anaerobic soil disinfestation treatments were highly effective against Potato Cyst Nematode (PCN), with pathogen being eradicated totally in all but one ASD treatment (glacial sand ASD2) within two weeks. The relative abundance of Firmicutes (spore-forming bacteria, often fermentative) in total bacteria increased significantly in ASD treated soils. Numbers of these bacteria correlated positively with increased concentrations of acetic and butyric acids in soil water phase in ASD treatments. PMID:26084078

  9. Rethinking energy in parkinsonian motor symptoms: a potential role for neural metabolic deficits

    PubMed Central

    Amano, Shinichi; Kegelmeyer, Deborah; Hong, S. Lee

    2015-01-01

    Parkinson’s disease (PD) is characterized as a chronic and progressive neurodegenerative disorder that results in a variety of debilitating symptoms, including bradykinesia, resting tremor, rigidity, and postural instability. Research spanning several decades has emphasized basal ganglia dysfunction, predominantly resulting from dopaminergic (DA) cell loss, as the primarily cause of the aforementioned parkinsonian features. But, why those particular features manifest themselves remains an enigma. The goal of this paper is to develop a theoretical framework that parkinsonian motor features are behavioral consequence of a long-term adaptation to their inability (inflexibility or lack of capacity) to meet energetic demands, due to neural metabolic deficits arising from mitochondrial dysfunction associated with PD. Here, we discuss neurophysiological changes that are generally associated with PD, such as selective degeneration of DA neurons in the substantia nigra pars compacta (SNc), in conjunction with metabolic and mitochondrial dysfunction. We then characterize the cardinal motor symptoms of PD, bradykinesia, resting tremor, rigidity and gait disturbance, reviewing literature to demonstrate how these motor patterns are actually energy efficient from a metabolic perspective. We will also develop three testable hypotheses: (1) neural metabolic deficits precede the increased rate of neurodegeneration and onset of behavioral symptoms in PD; (2) motor behavior of persons with PD are more sensitive to changes in metabolic/bioenergetic state; and (3) improvement of metabolic function could lead to better motor performance in persons with PD. These hypotheses are designed to introduce a novel viewpoint that can elucidate the connections between metabolic, neural and motor function in PD. PMID:25610377

  10. Determination of total energy expenditure, resting metabolic rate and physical activity in lean and overweight people

    Microsoft Academic Search

    F. Thielecke; J. Möseneder; A. Kroke; K. Klipstein-Grobusch; H. Boeing; R. Noack

    1997-01-01

    Summary A new2H\\/1H and18O\\/16O equilibration device was tested, standardized and employed for the determination of total energy expenditure. It was shown that overweight men and women have increased resting metabolic rate as well as increased total energy expenditure when compared to their lean counterparts. The physical activity level (PAL)index was slightly decreased which possibly suggests a decreased physical activity in

  11. Determination of total energy expenditure, resting metabolic rate and physical activity in lean and overweight people.

    PubMed

    Thielecke, F; Möseneder, J; Kroke, A; Klipstein-Grobusch, K; Boeing, H; Noack, R

    1997-12-01

    A new 2H/1H and 18O/16O equilibration device was tested, standardized and employed for the determination of total energy expenditure. It was shown that overweight men and women have increased resting metabolic rate as well as increased total energy expenditure when compared to their lean counterparts. The physical activity level (PAL)index was slightly decreased which possibly suggests a decreased physical activity in obese people. PMID:9467223

  12. Effect of parathyroid hormone on myocardial energy metabolism in the rat

    Microsoft Academic Search

    Ryszard Baczynski; Shaul G Massry; Ricardo Kohan; Maria Magott; Yahya Saglikes; Nachman Brautbar

    1985-01-01

    Effect of parathyroid hormone on myocardial energy metabolism in the rat. This study examined the effect of parathyroid hormone (PTH) on myocardial energy production, transfer, and utilization. Rats (150 to 200 g) were injected with 1-84 PTH, 200 U\\/day i.p., or 1-34 PTH, 200 or 300 U\\/day i.p., for 4 days. Control animals received the vehicle only. The effect of

  13. The effect of glucagon-like peptide-1 on energy expenditure and substrate metabolism in humans

    Microsoft Academic Search

    A Flint; A Raben; JF Rehfeld; JJ Holst; A Astrup

    2000-01-01

    OBJECTIVE: To investigate the effects of a near-physiological peripheral glucagon-like peptide-1 (GLP-1) infusion, during and after a breakfast of fixed energy content, on resting energy expenditure, substrate oxidation and metabolism and the desire to eat specific types of food in humans.DESIGN: A placebo-controlled, randomized, blinded, cross-over study. Infusion (GLP-1, 50 pmol\\/kg×h or saline) was started simultaneously with initiation of the

  14. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal.

    PubMed

    Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc; Nielsen, Jeppe Lund; Wimmer, Reinhard; Le, Vang Quy; McIlroy, Simon Jon; Petrovski, Steve; Seviour, Robert J; Calteau, Alexandra; Nielsen, Kåre Lehmann; Nielsen, Per Halkjær

    2013-03-01

    Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to 'Candidatus Accumulibacter phosphatis' is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenkinsii) were sequenced and annotated, and the data used to construct metabolic models. These models incorporate central aspects of carbon and phosphorus metabolism critical to understanding their behavior under the alternating anaerobic/aerobic conditions encountered in EBPR systems. Key features of these metabolic pathways were investigated in pure cultures, although poor growth limited their analyses to T. japonica and T. elongata. Based on the models, we propose that under anaerobic conditions the Tetrasphaera-related PAOs take up glucose and ferment this to succinate and other components. They also synthesize glycogen as a storage polymer, using energy generated from the degradation of stored polyphosphate and substrate fermentation. During the aerobic phase, the stored glycogen is catabolized to provide energy for growth and to replenish the intracellular polyphosphate reserves needed for subsequent anaerobic metabolism. They are also able to denitrify. This physiology is markedly different to that displayed by 'Candidatus Accumulibacter phosphatis', and reveals Tetrasphaera populations to be unusual and physiologically versatile PAOs carrying out denitrification, fermentation and polyphosphate accumulation. PMID:23178666

  15. Metabolic evolution of energy-conserving pathways for succinate production in Escherichia coli

    PubMed Central

    Zhang, Xueli; Jantama, Kaemwich; Moore, Jonathan C.; Jarboe, Laura R.; Shanmugam, Keelnatham T.; Ingram, Lonnie O.

    2009-01-01

    During metabolic evolution to improve succinate production in Escherichia coli strains, significant changes in cellular metabolism were acquired that increased energy efficiency in two respects. The energy-conserving phosphoenolpyruvate (PEP) carboxykinase (pck), which normally functions in the reverse direction (gluconeogenesis; glucose repressed) during the oxidative metabolism of organic acids, evolved to become the major carboxylation pathway for succinate production. Both PCK enzyme activity and gene expression levels increased significantly in two stages because of several mutations during the metabolic evolution process. High-level expression of this enzyme-dominated CO2 fixation and increased ATP yield (1 ATP per oxaloacetate). In addition, the native PEP-dependent phosphotransferase system for glucose uptake was inactivated by a mutation in ptsI. This glucose transport function was replaced by increased expression of the GalP permease (galP) and glucokinase (glk). Results of deleting individual transport genes confirmed that GalP served as the dominant glucose transporter in evolved strains. Using this alternative transport system would increase the pool of PEP available for redox balance. This change would also increase energy efficiency by eliminating the need to produce additional PEP from pyruvate, a reaction that requires two ATP equivalents. Together, these changes converted the wild-type E. coli fermentation pathway for succinate into a functional equivalent of the native pathway that nature evolved in succinate-producing rumen bacteria. PMID:19918073

  16. A Scalable Algorithm to Explore the Gibbs Energy Landscape of Genome-Scale Metabolic Networks

    PubMed Central

    De Martino, Daniele; Figliuzzi, Matteo

    2012-01-01

    The integration of various types of genomic data into predictive models of biological networks is one of the main challenges currently faced by computational biology. Constraint-based models in particular play a key role in the attempt to obtain a quantitative understanding of cellular metabolism at genome scale. In essence, their goal is to frame the metabolic capabilities of an organism based on minimal assumptions that describe the steady states of the underlying reaction network via suitable stoichiometric constraints, specifically mass balance and energy balance (i.e. thermodynamic feasibility). The implementation of these requirements to generate viable configurations of reaction fluxes and/or to test given flux profiles for thermodynamic feasibility can however prove to be computationally intensive. We propose here a fast and scalable stoichiometry-based method to explore the Gibbs energy landscape of a biochemical network at steady state. The method is applied to the problem of reconstructing the Gibbs energy landscape underlying metabolic activity in the human red blood cell, and to that of identifying and removing thermodynamically infeasible reaction cycles in the Escherichia coli metabolic network (iAF1260). In the former case, we produce consistent predictions for chemical potentials (or log-concentrations) of intracellular metabolites; in the latter, we identify a restricted set of loops (23 in total) in the periplasmic and cytoplasmic core as the origin of thermodynamic infeasibility in a large sample () of flux configurations generated randomly and compatibly with the prior information available on reaction reversibility. PMID:22737065

  17. Energy metabolism and glutamate-glutamine cycle in the brain: a stoichiometric modeling perspective

    PubMed Central

    2013-01-01

    Background The energetics of cerebral activity critically relies on the functional and metabolic interactions between neurons and astrocytes. Important open questions include the relation between neuronal versus astrocytic energy demand, glucose uptake and intercellular lactate transfer, as well as their dependence on the level of activity. Results We have developed a large-scale, constraint-based network model of the metabolic partnership between astrocytes and glutamatergic neurons that allows for a quantitative appraisal of the extent to which stoichiometry alone drives the energetics of the system. We find that the velocity of the glutamate-glutamine cycle (Vcyc) explains part of the uncoupling between glucose and oxygen utilization at increasing Vcyc levels. Thus, we are able to characterize different activation states in terms of the tissue oxygen-glucose index (OGI). Calculations show that glucose is taken up and metabolized according to cellular energy requirements, and that partitioning of the sugar between different cell types is not significantly affected by Vcyc. Furthermore, both the direction and magnitude of the lactate shuttle between neurons and astrocytes turn out to depend on the relative cell glucose uptake while being roughly independent of Vcyc. Conclusions These findings suggest that, in absence of ad hoc activity-related constraints on neuronal and astrocytic metabolism, the glutamate-glutamine cycle does not control the relative energy demand of neurons and astrocytes, and hence their glucose uptake and lactate exchange. PMID:24112710

  18. DJ-1 links muscle ROS production with metabolic reprogramming and systemic energy homeostasis in mice

    PubMed Central

    Shi, Sally Yu; Lu, Shun-Yan; Sivasubramaniyam, Tharini; Revelo, Xavier S.; Cai, Erica P.; Luk, Cynthia T.; Schroer, Stephanie A.; Patel, Prital; Kim, Raymond H.; Bombardier, Eric; Quadrilatero, Joe; Tupling, A. Russell; Mak, Tak W.; Winer, Daniel A.; Woo, Minna

    2015-01-01

    Reactive oxygen species (ROS) have been linked to a wide variety of pathologies, including obesity and diabetes, but ROS also act as endogenous signalling molecules, regulating numerous biological processes. DJ-1 is one of the most evolutionarily conserved proteins across species, and mutations in DJ-1 have been linked to some cases of Parkinson's disease. Here we show that DJ-1 maintains cellular metabolic homeostasis via modulating ROS levels in murine skeletal muscles, revealing a role of DJ-1 in maintaining efficient fuel utilization. We demonstrate that, in the absence of DJ-1, ROS uncouple mitochondrial respiration and activate AMP-activated protein kinase, which triggers Warburg-like metabolic reprogramming in muscle cells. Accordingly, DJ-1 knockout mice exhibit higher energy expenditure and are protected from obesity, insulin resistance and diabetes in the setting of fuel surplus. Our data suggest that promoting mitochondrial uncoupling may be a potential strategy for the treatment of obesity-associated metabolic disorders. PMID:26077864

  19. DJ-1 links muscle ROS production with metabolic reprogramming and systemic energy homeostasis in mice.

    PubMed

    Shi, Sally Yu; Lu, Shun-Yan; Sivasubramaniyam, Tharini; Revelo, Xavier S; Cai, Erica P; Luk, Cynthia T; Schroer, Stephanie A; Patel, Prital; Kim, Raymond H; Bombardier, Eric; Quadrilatero, Joe; Tupling, A Russell; Mak, Tak W; Winer, Daniel A; Woo, Minna

    2015-01-01

    Reactive oxygen species (ROS) have been linked to a wide variety of pathologies, including obesity and diabetes, but ROS also act as endogenous signalling molecules, regulating numerous biological processes. DJ-1 is one of the most evolutionarily conserved proteins across species, and mutations in DJ-1 have been linked to some cases of Parkinson's disease. Here we show that DJ-1 maintains cellular metabolic homeostasis via modulating ROS levels in murine skeletal muscles, revealing a role of DJ-1 in maintaining efficient fuel utilization. We demonstrate that, in the absence of DJ-1, ROS uncouple mitochondrial respiration and activate AMP-activated protein kinase, which triggers Warburg-like metabolic reprogramming in muscle cells. Accordingly, DJ-1 knockout mice exhibit higher energy expenditure and are protected from obesity, insulin resistance and diabetes in the setting of fuel surplus. Our data suggest that promoting mitochondrial uncoupling may be a potential strategy for the treatment of obesity-associated metabolic disorders. PMID:26077864

  20. Genome-scale estimate of the metabolic turnover of E. Coli from the energy balance analysis

    E-print Network

    De Martino, Daniele

    2015-01-01

    In this article the notion of metabolic turnover is revisited in the light of recent results of out-of-equilibrium thermodynamics. By means of Monte Carlo methods we perform an exact uniform sampling of the steady state fluxes in a genome scale metabolic network of E Coli from which we infer the metabolites turnover times. However the latter are inferred from net fluxes, and we argue that this approximation is not valid for enzymes working nearby thermodynamic equilibrium. We recalculate turnover times from total fluxes by performing an energy balance analysis of the network and recurring to the fluctuation theorem. We find in many cases values one of order of magnitude lower, implying a faster picture of intermediate metabolism.

  1. The metabolism of amino acids in the bovine lens. Their oxidation as a source of energy

    PubMed Central

    Trayhurn, P.; Van Heyningen, Ruth

    1973-01-01

    1. The metabolism by the bovine lens of nine 14C-labelled l-amino acids was studied. These were: alanine, aspartate, glutamate, leucine, lysine, proline, serine, tyrosine and tryptophan. 2. All were taken up by the tissue and incorporated into protein. 3. Aspartate and glutamate, although poorly taken up, were readily metabolized to CO2. Radioactivity from glutamate was also found in glutathione, glutamine, proline and ophthalmic acid. Aspartate was converted into glutamate, glutathione, proline, alanine and lactate. 4. Alanine was largely converted into lactate, which was released into the medium, but incorporation of radioactivity into CO2, glutamate, glutathione, aspartate and lipids also occurred. 5. Radioactivity from leucine was detected in CO2, lipids, glutamate, glutathione, proline and glutamine. 6. Lysine was only slightly broken down by the bovine lens; radioactivity was observed in CO2, glutamate, glutathione, proline and two unidentified compounds. 7. Proline was metabolized to glutamate from which CO2, glutathione and glutamine were formed. Hydroxyproline in the capsule collagen was labelled. 8. Radioactivity from serine was found in CO2, lipids, glutathione, glycine, cystine, ATP, lactate and three unidentified compounds, one of which was probably taurine. 9. Neither tyrosine nor tryptophan were metabolized by the bovine lens. 10. The ability of the lens to metabolize amino acids was also shown by measurement of NH3 production: more NH3 was formed when glucose was absent from the incubation medium. 11. These experiments suggest that oxidation of amino acids is a source of energy for the lens. PMID:4772629

  2. Bile Acid Binding Resin Improves Metabolic Control through the Induction of Energy Expenditure

    PubMed Central

    Watanabe, Mitsuhiro; Morimoto, Kohkichi; Houten, Sander M.; Kaneko-Iwasaki, Nao; Sugizaki, Taichi; Horai, Yasushi; Mataki, Chikage; Sato, Hiroyuki; Murahashi, Karin; Arita, Eri; Schoonjans, Kristina; Suzuki, Tatsuya; Itoh, Hiroshi; Auwerx, Johan

    2012-01-01

    Background Besides well-established roles of bile acids (BA) in dietary lipid absorption and cholesterol homeostasis, it has recently become clear that BA is also a biological signaling molecule. We have shown that strategies aimed at activating TGR5 by increasing the BA pool size with BA administration may constitute a significant therapeutic advance to combat the metabolic syndrome and suggest that such strategies are worth testing in a clinical setting. Bile acid binding resin (BABR) is known not only to reduce serum cholesterol levels but also to improve glucose tolerance and insulin resistance in animal models and humans. However, the mechanisms by which BABR affects glucose homeostasis have not been established. We investigated how BABR affects glycemic control in diet-induced obesity models. Methods and Findings We evaluated the metabolic effect of BABR by administrating colestimide to animal models for the metabolic syndrome. Administration of BABR increased energy expenditure, translating into significant weight reduction and insulin sensitization. The metabolic effects of BABR coincide with activation of cholesterol and BA synthesis in liver and thermogenesis in brown adipose tissue. Interestingly, these effects of BABR occur despite normal food intake and triglyceride absorption. Administration of BABR and BA had similar effects on BA composition and thermogenesis, suggesting that they both are mediated via TGR5 activation. Conclusion Our data hence suggest that BABR could be useful for the management of the impaired glucose tolerance of the metabolic syndrome, since they not only lower cholesterol levels, but also reduce obesity and improve insulin resistance. PMID:22952571

  3. Impact of hypothalamic reactive oxygen species in the regulation of energy metabolism and food intake

    PubMed Central

    Drougard, Anne; Fournel, Audren; Valet, Philippe; Knauf, Claude

    2015-01-01

    Hypothalamus is a key area involved in the control of metabolism and food intake via the integrations of numerous signals (hormones, neurotransmitters, metabolites) from various origins. These factors modify hypothalamic neurons activity and generate adequate molecular and behavioral responses to control energy balance. In this complex integrative system, a new concept has been developed in recent years, that includes reactive oxygen species (ROS) as a critical player in energy balance. ROS are known to act in many signaling pathways in different peripheral organs, but also in hypothalamus where they regulate food intake and metabolism by acting on different types of neurons, including proopiomelanocortin (POMC) and agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons. Hypothalamic ROS release is under the influence of different factors such as pancreatic and gut hormones, adipokines (leptin, apelin,…), neurotransmitters and nutrients (glucose, lipids,…). The sources of ROS production are multiple including NADPH oxidase, but also the mitochondria which is considered as the main ROS producer in the brain. ROS are considered as signaling molecules, but conversely impairment of this neuronal signaling ROS pathway contributes to alterations of autonomic nervous system and neuroendocrine function, leading to metabolic diseases such as obesity and type 2 diabetes. In this review we focus our attention on factors that are able to modulate hypothalamic ROS release in order to control food intake and energy metabolism, and whose deregulations could participate to the development of pathological conditions. This novel insight reveals an original mechanism in the hypothalamus that controls energy balance and identify hypothalamic ROS signaling as a potential therapeutic strategy to treat metabolic disorders. PMID:25759638

  4. Consequences of complex environments: Temperature and energy intake interact to influence growth and metabolic rate.

    PubMed

    Stahlschmidt, Zachary R; Jodrey, Alicia D; Luoma, Rachel L

    2015-09-01

    The field of comparative physiology has a rich history of elegantly examining the effects of individual environmental factors on performance traits linked to fitness (e.g., thermal performance curves for locomotion). However, animals live in complex environments wherein multiple environmental factors co-vary. Thus, we investigated the independent and interactive effects of temperature and energy intake on the growth and metabolic rate of juvenile corn snakes (Pantherophis guttatus) in the context of shifts in complex environments. Unlike previous studies that imposed constant or fluctuating temperature regimes, we manipulated the availability of preferred thermal microclimates (control vs. relatively warm regimes) for eight weeks and allowed snakes to behaviorally thermoregulate among microclimates. By also controlling for energy intake, we demonstrate an interactive effect of temperature and energy on growth-relevant temperature shifts had no effect on snakes' growth when energy intake was low and a positive effect on growth when energy intake was high. Thus, acclimation to relatively warm thermal options can result in increased rates of growth when food is abundant in a taxon in which body size confers fitness advantages. Temperature and energy also interactively influenced metabolic rate-snakes in the warmer temperature regime exhibited reduced metabolic rate (O2 consumption rate at 25°C and 30°C) if they had relatively high energy intake. Although we advocate for continued investigation into the effects of complex environments on other traits, our results indicate that warming may actually benefit important life history traits in some taxa and that metabolic shifts may underlie thermal acclimation. PMID:25899738

  5. Genetic and biochemical analysis of anaerobically-induced enzymes during seed germination of Echinochloa crus-galli varieties tolerant and intolerant of anoxia

    Microsoft Academic Search

    Takeshi Fukao; Robert A. Kennedy; Yuji Yamasue; Mary E. Rumpho

    2003-01-01

    To compare the regulation of anaerobic metabolism during germination in anoxia-tolerant and intolerant plants, enzymes associated with anaerobic metabol- ism such as sucrose synthase, aldolase, enolase, pyruvate decarboxylase (PDC), alcohol dehydrogen- ase (ADH), and aldehyde dehydrogenase (ALDH) were assayed in two varieties of Echinochloa crus- galli, formosensis (tolerant) and praticola (intolerant). The initial and intervening enzymes of the pathway (sucrose

  6. Metabolic myopathies

    NASA Technical Reports Server (NTRS)

    Martin, A.; Haller, R. G.; Barohn, R.; Blomqvist, C. G. (Principal Investigator)

    1994-01-01

    Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. Cardiac and systemic metabolic dysfunction may coexist. Symptoms are often intermittent and provoked by exercise or changes in supply of lipid and carbohydrate fuels. Specific disorders of lipid and carbohydrate metabolism in muscle are reviewed. Evaluation often requires provocative exercise testing. These tests may include ischemic forearm exercise, aerobic cycle exercise, and 31P magnetic resonance spectroscopy with exercise.

  7. The influence of metabolic network structures and energy requirements on xanthan gum yields.

    PubMed

    Letisse, Fabien; Chevallereau, Paule; Simon, Jean-Luc; Lindley, Nic

    2002-11-13

    The metabolic network of Xanthomonas campestris is complex since a number of cyclic pathways are present making simple stoichiometric yield predictions difficult. The influence of certain pathway configurations and the resulting variations in flux have been examined as regards the maximum yield potential of this bacteria for xanthan gum production. These predictions have been compared with experimental results showing that the strain employed is functioning close to its theoretical maximum as regards yield criteria. The major constraint imposed on the network concerns energy availability which has a more pronounced effect on yield than carbon precursor supply. This can be attributed to the relatively high maintenance requirements determined experimentally and incorporated into the model. While some of this overall energy burden will undoubtedly be associated with incompressible metabolic requirements such as sugar uptake and xanthan efflux mechanisms, future strain improvement strategies will need to attack other non-essential energy-consuming reactions, if yields are to be further increased. PMID:12385717

  8. Spatial control of the energy metabolism of yeast cells through electrolytic generation of oxygen

    NASA Astrophysics Data System (ADS)

    Warnke, Christian; Mair, Thomas; Witte, Hartmut; Reiher, Antje; Hauser, Marcus J. B.; Krost, Alois

    2009-12-01

    The metabolic dynamics of yeast cells is controlled by electric pulses delivered through a spatially extended yeast cell/Au electrode interface. Concomitant with voltage pulses, oxygen is generated electrolytically at the electrode surface and delivered to the cells. The generation of oxygen was investigated in dependence of the applied voltage, width of the voltage pulses and temperature of the electrolytic solution. The local oxygen pulses at the electrodes lead to a transient activation of the aerobic energy metabolism of the yeast cells causing a perturbation in their energy balance. The effect of these local perturbations on the temporal dynamics of glycolysis in yeast cells is quantified in dependence of the energy state of cells.

  9. Teaching the Role of Mitochondrial Transport in Energy Metabolism

    ERIC Educational Resources Information Center

    Passarella, Salvatore; Atlante, Anna

    2007-01-01

    Studies from our laboratories over recent years have uncovered the existence, and established the properties of a variety of mitochondrial transporters. The properties of these transporters throw light on a variety of biochemical phenomena that were previously poorly understood. In particular the role of mitochondrial transport in energy

  10. Thermodynamic analysis of fermentation and anaerobic growth of baker's yeast for ethanol production.

    PubMed

    Teh, Kwee-Yan; Lutz, Andrew E

    2010-05-17

    Thermodynamic concepts have been used in the past to predict microbial growth yield. This may be the key consideration in many industrial biotechnology applications. It is not the case, however, in the context of ethanol fuel production. In this paper, we examine the thermodynamics of fermentation and concomitant growth of baker's yeast in continuous culture experiments under anaerobic, glucose-limited conditions, with emphasis on the yield and efficiency of bio-ethanol production. We find that anaerobic metabolism of yeast is very efficient; the process retains more than 90% of the maximum work that could be extracted from the growth medium supplied to the chemostat reactor. Yeast cells and other metabolic by-products are also formed, which reduces the glucose-to-ethanol conversion efficiency to less than 75%. Varying the specific ATP consumption rate, which is the fundamental parameter in this paper for modeling the energy demands of cell growth, shows the usual trade-off between ethanol production and biomass yield. The minimum ATP consumption rate required for synthesizing cell materials leads to biomass yield and Gibbs energy dissipation limits that are much more severe than those imposed by mass balance and thermodynamic equilibrium constraints. PMID:20184925

  11. Anaerobic Biotransformation of Trichlorofluoroethene in

    E-print Network

    Semprini, Lewis

    Anaerobic Biotransformation of Trichlorofluoroethene in Groundwater Microcosms S A N J A Y V A N C, and other macrocycles. Anaerobic biotransformation is now recognized as an important if not dominant factor

  12. TRPV1 activation improves exercise endurance and energy metabolism through PGC-1? upregulation in mice

    PubMed Central

    Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

    2012-01-01

    Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-? coactivator-1? (PGC-1?) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1? in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1? in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance. PMID:22184011

  13. Quantification of patterns of regional cardiac metabolism

    SciTech Connect

    Lear, J.L.; Ackermann, R.F. (Univ. of Colorado Health Sciences Center, Denver (USA))

    1990-09-01

    To quantitatively map and compare patterns of regional cardiac metabolism with greater spatial resolution than is possible with positron emission tomography (PET), the authors developed autoradiographic techniques for use with combinations of radiolabeled fluorodeoxyglucose (FDG), glucose (GLU), and acetate (ACE) and applied the techniques to normal rats. Kinetic models were developed to compare GLU-based oxidative glucose metabolism with FDG-based total glucose metabolism (oxidative plus anaerobic) and to compare ACE-based overall oxidative metabolism with FDG-based total glucose metabolism. GLU-based metabolism generally paralleled FDG-based metabolism, but divergence occurred in certain structures such as the papillary muscles, where FDG-based metabolism was much greater. ACE-based metabolism also generally paralleled FDG-based metabolism, but again, the papillary muscles had relatively greater FDG-based metabolism. These discrepancies between FDG-based metabolism and GLU- or ACE-based metabolism suggest the presence of high levels of anaerobic glycolysis. Thus, the study indicates that anaerobic glycolysis, in addition to occurring in ischemic or stunned myocardium (as has been shown in recent PET studies), occurs normally in specific cardiac regions, despite the presence of abundant oxygen.

  14. A bioassay to measure energy metabolism in mouse colonic crypts, organoids, and sorted stem cells.

    PubMed

    Fan, Yang-Yi; Davidson, Laurie A; Callaway, Evelyn S; Wright, Gus A; Safe, Stephen; Chapkin, Robert S

    2015-07-01

    Evidence suggests that targeting cancer cell energy metabolism might be an effective therapeutic approach for selective ablation of malignancies. Using a Seahorse Extracellular Flux Analyzer, we have demonstrated that select environmental agents can alter colonic mitochondrial function by increasing respiration-induced proton leak, thereby inducing apoptosis, a marker of colon cancer risk. To further probe bioenergetics in primary intestinal cells, we developed methodology that can be modified and adapted to measure the bioenergetic profiles of colonic crypts, the basic functional unit of the colon, and colonic organoids, an ex vivo 3D culture of colonic crypts. Furthermore, in combination with the MoFlo Astrios High-Speed Cell Sorter, we were able to measure the bioenergetic profiles of colonic adult stem and daughter cells from Lgr5-EGFP-IRES-creER(T2) transgenic mice. We examined the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a full arylhydrocarbon receptor agonist, known to affect gastrointestinal function and cancer risk, on the bioenergetic profiles of intestinal epithelial cells. Mouse colonic crypts, organoids, or sorted single cells were seeded onto Matrigel-precoated Seahorse XF24 microplates for extracellular flux analysis. Temporal analyses revealed distinct energy metabolic profiles in crypts and organoids challenged with TCDD. Furthermore, sorted Lgr5(+) stem cells exhibited a Warburg-like metabolic profile. This is noteworthy because perturbations in stem cell dynamics are generally believed to represent the earliest step toward colon tumorigenesis. We propose that our innovative methodology may facilitate future in vivo/ex vivo metabolic studies using environmental agents affecting colonocyte energy metabolism. PMID:25977509

  15. Production of nitrous oxide from anaerobic digester centrate and its use as a co-oxidant of biogas to enhance energy recovery.

    PubMed

    Scherson, Yaniv D; Woo, Sung-Geun; Criddle, Craig S

    2014-05-20

    Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH4(+) oxidation to NO2(-); (2) NO2(-) reduction to N2O gas; and (3) N2O conversion to N2 with energy production. In this work, we optimize Steps 1 and 2 for anaerobic digester centrate, and we evaluate Step 3 for a full-scale biogas-fed internal combustion engine. Using a continuous stirred reactor coupled to a bench-scale sequencing batch reactor, we observed sustained partial oxidation of NH4(+) to NO2(-) and sustained (3 months) partial reduction of NO2(-) to N2O (75-80% conversion, mass basis), with >95% nitrogen removal (Step 2). Alternating pulses of acetate and NO2(-) selected for Comamonas (38%), Ciceribacter (16%), and Clostridium (11%). Some species stored polyhydroxybutyrate (PHB) and coupled oxidation of PHB to reduction of NO2(-) to N2O. Some species also stored phosphorus as polyphosphate granules. Injections of N2O into a biogas-fed engine at flow rates simulating a full-scale system increased power output by 5.7-7.3%. The results underscore the need for more detailed assessment of bioreactor community ecology and justify pilot- and full-scale testing. PMID:24780056

  16. An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

    SciTech Connect

    Ross Overbeek, Veronika Fonstein, Andrei Osterman, Svetlana Gerdes, Olga Vassieva, Olga Zagnitko, Dmitry Rodionov

    2005-02-15

    The team of the Fellowship for Interpretation of Genomes (FIG) under the leadership of Ross Overbeek, began working on this Project in November 2003. During the previous year, the Project was performed at Integrated Genomics Inc. A transition from the industrial environment to the public domain prompted us to adjust some aspects of the Project. Notwithstanding the challenges, we believe that these adjustments had a strong positive impact on our deliverables. Most importantly, the work of the research team led by R. Overbeek resulted in the deployment of a new open source genomic platform, the SEED (Specific Aim 1). This platform provided a foundation for the development of CyanoSEED a specialized portal to comparative analysis and metabolic reconstruction of all available cyanobacterial genomes (Specific Aim 3). The SEED represents a new generation of software for genome analysis. Briefly, it is a portable and extendable system, containing one of the largest and permanently growing collections of complete and partial genomes. The complete system with annotations and tools is freely available via browsing or via installation on a user's Mac or Linux computer. One of the important unique features of the SEED is the support of metabolic reconstruction and comparative genome analysis via encoding and projection of functional subsystems. During the project period, the FIG research team has validated the new software by developing a significant number of core subsystems, covering many aspects of central metabolism (Specific Aim 2), as well as metabolic areas specific for cyanobacteria and other photoautotrophic organisms (Specific Aim 3). In addition to providing a proof of technology and a starting point for further community-based efforts, these subsystems represent a valuable asset. An extensive coverage of central metabolism provides the bulk of information required for metabolic modeling in Synechocystis sp.PCC 6803. Detailed analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and other cyanobacteria has been performed (Specific Aim 4). The main objectives for this year (adjusted to reflect a new, public domain, setting of the Project research team) were: Aim 1. To develop, test, and deploy a new open source system, the SEED, for integrating community-based annotation, and comparative analysis of all publicly available microbial genomes. Develop a comprehensive genomic database by integrating within SEED all publicly available complete and nearly complete genome sequences with special emphasis on genomes of cyanobacteria, phototrophic eukaryotes, and anoxygenic phototrophic bacteria--invaluable for comparative genomic studies of energy and carbon metabolism in Synechocystis sp. PCC 6803. Aim 2. To develop the SEED's biological content in the form of a collection of encoded Subsystems largely covering the conserved cellular machinery in prokaryotes (and central metabolic machinery in eukaryotes). Aim 3. To develop, utilizing core SEED technology, the CyanoSEED--a specialized WEB portal for community-based annotation, and comparative analysis of all publicly available cyanobacterial genomes. Encode the set of additional subsystems representing key metabolic transformations in cyanobacteria and other photoautotrophs. We envisioned this resource as complementary to other public access databases for comparative genomic analysis currently available to the cyanobacterial research community. Aim 4. Perform in-depth analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and all other cyanobacteria with available genome sequences. Reveal inconsistencies and gaps in the current knowledge of these subsystems. Use functional and genome context analysis tools in CyanoSEED to predict, whenever possible, candidate genes for inferred functional roles. To disseminate freely these conjectures and predictions by publishing them on CyanoSEED (http://cyanoseed.thefig.info/) and the Subsystems Forum (http://brucella.uchicago.edu/Su

  17. A shift in energy metabolism anticipates the onset of sarcopenia in rhesus monkeys

    PubMed Central

    Pugh, Thomas D.; Conklin, Matthew W.; Evans, Trent D.; Polewski, Michael A.; Barbian, Hannah J.; Pass, Rachelle; Anderson, Bradley D.; Colman, Ricki J.; Eliceiri, Kevin W.; Keely, Patricia J.; Weindruch, Richard; Beasley, T. Mark; Anderson, Rozalyn M.

    2013-01-01

    Summary Age-associated skeletal muscle mass loss curtails quality of life and may contribute to defects in metabolic homeostasis in older persons. The onset of sarcopenia occurs in middle age in rhesus macaques although the trigger has yet to be identified. Here we show that a shift in metabolism occurs in advance of the onset of sarcopenia in rhesus vastus lateralis. Multiphoton laser scanning microscopy detects a shift in the kinetics of photon emission from autofluorescent metabolic cofactors NADH and FAD. Lifetime of both fluorophores is shortened at mid-age and this is observed in both free and bound constituent pools. Levels of FAD and free NADH are increased and the NAD/NADH redox ratio is lower. Concomitant with this, expression of fiber type myosin isoforms is altered resulting in a shift in fiber type distribution, activity of cytochrome c oxidase involved in mitochondrial oxidative phosphorylation is significantly lower, and the sub-cellular organization of mitochondria in oxidative fibers is compromised. A regulatory switch involving the transcriptional coactivator PGC-1? directs metabolic fuel utilization and governs the expression of structural proteins. Age did not significantly impact total levels of PGC-1?; however, its sub-cellular localization was disrupted, suggesting that PGC-1? activities may be compromised. Consistent with this, intracellular lipid storage is altered and there is shift to larger lipid droplet size that likely reflect a decline in lipid turnover or a loss in efficiency of lipid metabolism. We suggest that changes in energy metabolism contribute directly to skeletal muscle aging in rhesus monkeys. PMID:23607901

  18. Effects of weekly administration of pegylated recombinant human OB protein on appetite profile and energy metabolism in obese men

    Microsoft Academic Search

    Margriet S Westerterp-Plantenga; Wim HM Saris; Chris J Hukshorn; L Arthur Campfield

    2001-01-01

    Background: Results of leptin administration in mice, rats, and humans provide a rationale for therapeutic augmentation of cir- culating leptin (OB protein) concentrations in obese humans; this may reduce food intake, increase metabolic rate, and lower body mass. Objective: We assessed the effects of weekly subcutaneous pegylated polyethylene glycol (PEG)-OB protein administration on appetite and energy metabolism in obese men.

  19. Food restriction affects energy metabolism in rat liver mitochondria. Jean-Franois DUMAS, Damien ROUSSEL, Gilles SIMARD, Olivier DOUAY, Franoise

    E-print Network

    Paris-Sud XI, Université de

    1 Food restriction affects energy metabolism in rat liver mitochondria. Jean-François DUMAS, Damien metabolism, liver mitochondria were isolated from ad libitum and food restricted rats. Mitochondrial enzyme, in food restricted rats, liver mitochondria displayed diminished state 3 (-30%), state 4-oligomycin (-26

  20. The Anaerobic Digestion of Organic

    E-print Network

    Iglesia, Enrique

    The Anaerobic Digestion of Organic Municipal Solid Waste in California. Anaerobic Digestion Technology 2.1. Feedstock Characterization 2.2. Collection & Sorting 2.2.1. Waste of Anaerobic Digestion 3.1. Municipal Waste Management 3.2. Climate Change Mitigation 3.2.1. Untreated

  1. Anaerobic digestion of ozonized biosolids

    Microsoft Academic Search

    M Weemaes; H Grootaerd; F Simoens; W Verstraete

    2000-01-01

    The effect of an oxidative pretreatment on the anaerobic digestion of sewage sludge was investigated. Sewage sludge from a domestic wastewater treatment plant was partially oxidized by ozone. The pretreatment could alter up to 67% of the organic matter: 29±3% was solubilized, 38±9% was removed. Anaerobic degradability tests indicated that the pretreatment step enhanced the subsequent anaerobic sludge digestion. The

  2. Decreased Energy Metabolism Extends Life Span in Caenorhabditis elegans Without Reducing Oxidative Damage

    PubMed Central

    Van Raamsdonk, Jeremy Michael; Meng, Yan; Camp, Darius; Yang, Wen; Jia, Xihua; Bénard, Claire; Hekimi, Siegfried

    2010-01-01

    On the basis of the free radical and rate of living theories of aging, it has been proposed that decreased metabolism leads to increased longevity through a decreased production of reactive oxygen species (ROS). In this article, we examine the relationship between mitochondrial energy metabolism and life span by using the Clk mutants in Caenorhabditis elegans. Clk mutants are characterized by slow physiologic rates, delayed development, and increased life span. This phenotype suggests that increased life span may be achieved by decreasing energy expenditure. To test this hypothesis, we identified six novel Clk mutants in a screen for worms that have slow defecation and slow development and that can be maternally rescued. Interestingly, all 11 Clk mutants have increased life span despite the fact that slow physiologic rates were used as the only screening criterion. Although mitochondrial function is decreased in the Clk mutants, ATP levels are normal or increased, suggesting decreased energy utilization. To determine whether the longevity of the Clk mutants results from decreased production of ROS, we examined sensitivity to oxidative stress and oxidative damage. We found no evidence for systematically increased resistance to oxidative stress or decreased oxidative damage in the Clk mutants despite normal or elevated levels of superoxide dismutases. Overall, our findings suggest that decreased energy metabolism can lead to increased life span without decreased production of ROS. PMID:20382831

  3. Simulating the physiology of athletes during endurance sports events: modelling human energy conversion and metabolism

    PubMed Central

    van Beek, Johannes H. G. M.; Supandi, Farahaniza; Gavai, Anand K.; de Graaf, Albert A.; Binsl, Thomas W.; Hettling, Hannes

    2011-01-01

    The human physiological system is stressed to its limits during endurance sports competition events. We describe a whole body computational model for energy conversion during bicycle racing. About 23 per cent of the metabolic energy is used for muscle work, the rest is converted to heat. We calculated heat transfer by conduction and blood flow inside the body, and heat transfer from the skin by radiation, convection and sweat evaporation, resulting in temperature changes in 25 body compartments. We simulated a mountain time trial to Alpe d'Huez during the Tour de France. To approach the time realized by Lance Armstrong in 2004, very high oxygen uptake must be sustained by the simulated cyclist. Temperature was predicted to reach 39°C in the brain, and 39.7°C in leg muscle. In addition to the macroscopic simulation, we analysed the buffering of bursts of high adenosine triphosphate hydrolysis by creatine kinase during cyclical muscle activity at the biochemical pathway level. To investigate the low oxygen to carbohydrate ratio for the brain, which takes up lactate during exercise, we calculated the flux distribution in cerebral energy metabolism. Computational modelling of the human body, describing heat exchange and energy metabolism, makes simulation of endurance sports events feasible. PMID:21969677

  4. Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy.

    PubMed

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2014-06-01

    The aerodynamic drag of a cyclist in time trial (TT) position is strongly influenced by the torso angle. While decreasing the torso angle reduces the drag, it limits the physiological functioning of the cyclist. Therefore the aims of this study were to predict the optimal TT cycling position as function of the cycling speed and to determine at which speed the aerodynamic power losses start to dominate. Two models were developed to determine the optimal torso angle: a 'Metabolic Energy Model' and a 'Power Output Model'. The Metabolic Energy Model minimised the required cycling energy expenditure, while the Power Output Model maximised the cyclists? power output. The input parameters were experimentally collected from 19 TT cyclists at different torso angle positions (0-24°). The results showed that for both models, the optimal torso angle depends strongly on the cycling speed, with decreasing torso angles at increasing speeds. The aerodynamic losses outweigh the power losses at cycling speeds above 46km/h. However, a fully horizontal torso is not optimal. For speeds below 30km/h, it is beneficial to ride in a more upright TT position. The two model outputs were not completely similar, due to the different model approaches. The Metabolic Energy Model could be applied for endurance events, while the Power Output Model is more suitable in sprinting or in variable conditions (wind, undulating course, etc.). It is suggested that despite some limitations, the models give valuable information about improving the cycling performance by optimising the TT cycling position. PMID:24726654

  5. Solar heated anaerobic digestor

    SciTech Connect

    Rhoades, D.

    1980-09-09

    A solar heated anaerobic digestor is provided, adapted to utilize organic material capable of decomposing to produce methane gas and a liquid fertilizer. The sealed anaerobic digestor is wrapped with a layer of heat absorptive material followed by a series of abutting removable panels of insulative material. Insulative panels may be temporarily removed to expose the heat absorptive material to solar radiation and may be replaced when the solar radiation diminishes. A layer of transparent material wrapped in outwardly spaced relation around the insulatng panels is capable of transmitting solar radiation while providing protection against environmental elements. Additional heating means extending into the digestor provide auxiliary heat as required.

  6. Anaerobic biotransformation of nitrocellulose

    SciTech Connect

    Duran, M.; Speece, R.E. (Vanderbilt Univ., Nashville, TN (United States). Environmental and Water Resources Engineering Dept.); Kim, B.J. (Army Corps of Engineers, Champaign, IL (United States). Construction Engineering Research Lab.)

    1994-01-01

    In this investigation, first the toxic effect of nitrocellulose (NC) on anaerobic microorganisms with and without the presence of a supplementary carbon source was evaluated. Then it was observed that with the addition of a supplementary carbon source, such as cellulose or acetate, biotransformation of NC was enhanced. The biodegradation rate of NC in a staged-feed and in a two-phase reactor under anaerobic conditions was evaluated. The results showed that providing cellulose as the supplementary carbon source, NC was degraded at a higher rate in a staged-feed reactor than in a two-phase reactor or in a batch reactor.

  7. Altered energy metabolism in an irradiated population of lizards at the Nevada Test Site

    SciTech Connect

    Nagy, K.A.; Medica, P.A.

    1985-07-01

    Field metabolic rates (via doubly labeled water), body compartmentalization of energy stores, and energy assimilation efficiencies were measured to assess all avenues of energy utilization in Uta stansburiana living in a low-level ..gamma..-irradiated plot in Rock Valley, Nevada. Comparison of energy budgets for radiation-sterilized females with those of nonirradiated control lizards revealed several substantial differences. Sterile females were heavier, mainly because they had extraordinarily large energy (fat) storage depots. Sterile females had much lower rates of energy expenditure via respiration and lower rates of energy intake by feeding. These differences are interpreted as indirect responses to radiation-induced sterility. There is little evidence of direct radiation effects on physiological functions other than reproduction.

  8. Altered energy metabolism in an irradiated population of lizards at the Nevada Test Site.

    PubMed

    Nagy, K A; Medica, P A

    1985-07-01

    Field metabolic rates (via doubly labeled water), body compartmentalization of energy stores, and energy assimilation efficiencies were measured to assess all avenues of energy utilization in Uta stansburiana living in a low-level gamma-irradiated plot in Rock-Valley, Nevada. Comparison of energy budgets for radiation-sterilized females with those of nonirradiated control lizards revealed several substantial differences. Sterile females were heavier, mainly because they had extraordinarily large energy (fat) storage depots. Sterile females had much lower rates of energy expenditure via respiration and lower rates of energy intake by feeding. These differences are interpreted as indirect responses to radiation-induced sterility. Gastrointestinal tract function in sterile females was normal. There is little evidence of direct radiation effects on physiological functions other than reproduction. PMID:4070562

  9. Effect of Short-Term Thyroxine Administration on Energy Metabolism and Mitochondrial Efficiency in Humans

    PubMed Central

    Johannsen, Darcy L.; Galgani, Jose E.; Johannsen, Neil M.; Zhang, Zhengyu; Covington, Jeffrey D.; Ravussin, Eric

    2012-01-01

    The physiologic effects of triiodothyronine (T3) on metabolic rate are well-documented; however, the effects of thyroxine (T4) are less clear despite its wide-spread use to treat thyroid-related disorders and other non-thyroidal conditions. Here, we investigated the effects of acute (3-day) T4 supplementation on energy expenditure at rest and during incremental exercise. Furthermore, we used a combination of in situ and in vitro approaches to measure skeletal muscle metabolism before and after T4 treatment. Ten healthy, euthyroid males were given 200 µg T4 (levothyroxine) per day for 3 days. Energy expenditure was measured at rest and during exercise by indirect calorimetry, and skeletal muscle mitochondrial function was assessed by in situ ATP flux (31P MRS) and in vitro respiratory control ratio (RCR, state 3/state 4 rate of oxygen uptake using a Clark-type electrode) before and after acute T4 treatment. Thyroxine had a subtle effect on resting metabolic rate, increasing it by 4% (p?=?0.059) without a change in resting ATP demand (i.e., ATP flux) of the vastus lateralis. Exercise efficiency did not change with T4 treatment. The maximal capacity to produce ATP (state 3 respiration) and the coupled state of the mitochondria (RCR) were reduced by approximately 30% with T4 (p?=?0.057 and p?=?0.04, respectively). Together, the results suggest that T4, although less metabolically active than T3, reduces skeletal muscle efficiency and modestly increases resting metabolism even after short-term supplementation. Our findings may be clinically relevant given the expanding application of T4 to treat non-thyroidal conditions such as obesity and weight loss. PMID:22844412

  10. A scalable algorithm to explore the Gibbs energy landscape of genome-scale metabolic networks

    E-print Network

    De Martino, Daniele; De Martino, Andrea; Marinari, Enzo; 10.1371/journal.pcbi.1002562

    2012-01-01

    The integration of various types of genomic data into predictive models of biological networks is one of the main challenges currently faced by computational biology. Constraint-based models in particular play a key role in the attempt to obtain a quantitative understanding of cellular metabolism at genome scale. In essence, their goal is to frame the metabolic capabilities of an organism based on minimal assumptions that describe the steady states of the underlying reaction network via suitable stoichiometric constraints, specifically mass balance and energy balance (i.e. thermodynamic feasibility). The implementation of these requirements to generate viable configurations of reaction fluxes and/or to test given flux profiles for thermodynamic feasibility can however prove to be computationally intensive. We propose here a fast and scalable stoichiometry-based method to explore the Gibbs energy landscape of a biochemical network at steady state. The method is applied to the problem of reconstructing the Gibb...

  11. Effect of Tiaoxin Recipe on spatial memory and energy metabolism of oxidation injured Alzheimers disease rats

    Microsoft Academic Search

    Qiu Hong; Jin Guo-qin; Zhao Wei-kang; Zhang Xue-li

    2003-01-01

    Objective: To observe the effect of Tiaoxin Recipe (TXR) on the spatial memory, brain mitochondrial energy metabolism of oxidation\\u000a injured Alzheimer’s disease (AD) rats, and to explore the mechanism of TXR in treating AD.Methods: Eighty-eight SD rats were randomly divided into five groups (normal group, operative group, “AD” model group, TXR group\\u000a and Aricept group). An oxygen free radical generation

  12. Characterization of energy conversion based on metabolic flux analysis in mixotrophic liverwort cells, Marchantia polymorpha

    Microsoft Academic Search

    Jun-ichi Hata; Qiang Hua; Chen Yang; Kazuyuki Shimizu; Masahito Taya

    2000-01-01

    In order to characterize the contributions of respiratory and photosynthetic actions to energy conversions, the mixotrophic cells of Marchantia polymorpha were cultivated in the medium containing 10kg\\/m3 glucose as an organic carbon source. The cultures were conducted with the supply of ordinary air (0.03% CO2) at constant incident light intensities of 50 and 180W\\/m2. From the results of metabolic analysis,

  13. Effect of bacterial protein meal on protein and energy metabolism in growing chickens

    Microsoft Academic Search

    Anne Louise F. Hellwing; Anne-Helene Tauson; Anders Skrede

    2006-01-01

    This experiment investigates the effect of increasing the dietary content of bacterial protein meal (BPM) on the protein and energy metabolism, and carcass chemical composition of growing chickens. Seventy-two Ross male chickens were allocated to four diets, each in three replicates with 0% (D0), 2% (D2), 4% (D4), and 6% BPM (D6), BPM providing up to 20% of total dietary

  14. Statins enhance peroxisome proliferator-activated receptor ? coactivator-1? activity to regulate energy metabolism

    Microsoft Academic Search

    Wenxian Wang; Chi-Wai Wong

    2010-01-01

    Peroxisome proliferator-activated receptor ? coactivator-1? (PGC-1?) serves as an inducible coactivator for a number of transcription\\u000a factors to control energy metabolism. Insulin signaling through Akt kinase has been demonstrated to phosphorylate PGC-1? at\\u000a serine 571 and downregulate its activity in the liver. Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors\\u000a that reduce cholesterol synthesis in the liver. In this study, we

  15. A failure in energy metabolism and antioxidant uptake precede symptoms of Huntington's disease in mice.

    PubMed

    Acuña, Aníbal I; Esparza, Magdalena; Kramm, Carlos; Beltrán, Felipe A; Parra, Alejandra V; Cepeda, Carlos; Toro, Carlos A; Vidal, René L; Hetz, Claudio; Concha, Ilona I; Brauchi, Sebastián; Levine, Michael S; Castro, Maite A

    2013-01-01

    Huntington's disease has been associated with a failure in energy metabolism and oxidative damage. Ascorbic acid is a powerful antioxidant highly concentrated in the brain where it acts as a messenger, modulating neuronal metabolism. Using an electrophysiological approach in R6/2 HD slices, we observe an abnormal ascorbic acid flux from astrocytes to neurons, which is responsible for alterations in neuronal metabolic substrate preferences. Here using striatal neurons derived from knock-in mice expressing mutant huntingtin (STHdhQ cells), we study ascorbic acid transport. When extracellular ascorbic acid concentration increases, as occurs during synaptic activity, ascorbic acid transporter 2 (SVCT2) translocates to the plasma membrane, ensuring optimal ascorbic acid uptake for neurons. In contrast, SVCT2 from cells that mimic HD symptoms (dubbed HD cells) fails to reach the plasma membrane under the same conditions. We reason that an early impairment of ascorbic acid uptake in HD neurons could lead to early metabolic failure promoting neuronal death. PMID:24336051

  16. The Energy Metabolism in Caenorhabditis elegans under The Extremely Low-Frequency Electromagnetic Field Exposure

    PubMed Central

    Shi, Zhenhua; Yu, Hui; Sun, Yongyan; Yang, Chuanjun; Lian, Huiyong; Cai, Peng

    2015-01-01

    A literal mountain of documentation generated in the past five decades showing unmistakable health hazards associated with extremely low-frequency electromagnetic fields (ELF-EMFs) exposure. However, the relation between energy mechanism and ELF-EMF exposure is poorly understood. In this study, Caenorhabditis elegans was exposed to 50?Hz ELF-EMF at intensities of 0.5, 1, 2, and 3?mT, respectively. Their metabolite variations were analyzed by GC-TOF/MS-based metabolomics. Although minimal metabolic variations and no regular pattern were observed, the contents of energy metabolism-related metabolites such as pyruvic acid, fumaric acid, and L-malic acid were elevated in all the treatments. The expressions of nineteen related genes that encode glycolytic enzymes were analyzed by using quantitative real-time PCR. Only genes encoding GAPDH were significantly upregulated (P < 0.01), and this result was further confirmed by western blot analysis. The enzyme activity of GAPDH was increased (P < 0.01), whereas the total intracellular ATP level was decreased. While no significant difference in lifespan, hatching rate and reproduction, worms exposed to ELF-EMF exhibited less food consumption compared with that of the control (P < 0.01). In conclusion, C. elegans exposed to ELF-EMF have enhanced energy metabolism and restricted dietary, which might contribute to the resistance against exogenous ELF-EMF stress. PMID:25683579

  17. Carnosine: can understanding its actions on energy metabolism and protein homeostasis inform its therapeutic potential?

    PubMed Central

    2013-01-01

    The dipeptide carnosine (?-alanyl-L-histidine) has contrasting but beneficial effects on cellular activity. It delays cellular senescence and rejuvenates cultured senescent mammalian cells. However, it also inhibits the growth of cultured tumour cells. Based on studies in several organisms, we speculate that carnosine exerts these apparently opposing actions by affecting energy metabolism and/or protein homeostasis (proteostasis). Specific effects on energy metabolism include the dipeptide’s influence on cellular ATP concentrations. Carnosine’s ability to reduce the formation of altered proteins (typically adducts of methylglyoxal) and enhance proteolysis of aberrant polypeptides is indicative of its influence on proteostasis. Furthermore these dual actions might provide a rationale for the use of carnosine in the treatment or prevention of diverse age-related conditions where energy metabolism or proteostasis are compromised. These include cancer, Alzheimer's disease, Parkinson's disease and the complications of type-2 diabetes (nephropathy, cataracts, stroke and pain), which might all benefit from knowledge of carnosine’s mode of action on human cells. PMID:23442334

  18. Energy metabolism in a matched model of radiation resistance for head and neck squamous cell cancer.

    PubMed

    Mims, Jade; Bansal, Nidhi; Bharadwaj, Manish S; Chen, Xiaofei; Molina, Anthony J; Tsang, Allen W; Furdui, Cristina M

    2015-03-01

    While radiation therapy is commonly used for treating cancer, radiation resistance can limit long-term control of the disease. In this study, we investigated the reprogramming of the energy metabolism in radiosensitive and radioresistant head and neck squamous cell carcinomas (HNSCC) using a preclinical matched model of radiation resistance. Our investigation found that radioresistant rSCC-61 cells: 1. They display increased glucose uptake and decreased fatty acid uptake; 2. They deviate from the classical Warburg effect by diverting the glycolytic flux into the pentose phosphate pathway; 3. They are more dependent on glucose than glutamine metabolism to support growth; 4. They have decreased mitochondrial oxidative phosphorylation; 5. They have enhanced fatty acid biosynthesis by increasing the expression of fatty acid synthase; and 6. They utilize endogenous fatty acids to meet the energy demands for proliferation. Inhibition of fatty acid synthase with orlistat or FASN siRNA resulted in increased cytotoxicity and sensitivity to radiation in rSCC-61 cells. These results demonstrate the potential of combination therapy using radiation and orlistat or other inhibitors of lipid and energy metabolism for treating radiation resistance in HNSCC. PMID:25738895

  19. UCP2 regulates energy metabolism and differentiation potential of human pluripotent stem cells

    PubMed Central

    Zhang, Jin; Khvorostov, Ivan; Hong, Jason S; Oktay, Yavuz; Vergnes, Laurent; Nuebel, Esther; Wahjudi, Paulin N; Setoguchi, Kiyoko; Wang, Geng; Do, Anna; Jung, Hea-Jin; McCaffery, J Michael; Kurland, Irwin J; Reue, Karen; Lee, Wai-Nang P; Koehler, Carla M; Teitell, Michael A

    2011-01-01

    It has been assumed, based largely on morphologic evidence, that human pluripotent stem cells (hPSCs) contain underdeveloped, bioenergetically inactive mitochondria. In contrast, differentiated cells harbour a branched mitochondrial network with oxidative phosphorylation as the main energy source. A role for mitochondria in hPSC bioenergetics and in cell differentiation therefore remains uncertain. Here, we show that hPSCs have functional respiratory complexes that are able to consume O2 at maximal capacity. Despite this, ATP generation in hPSCs is mainly by glycolysis and ATP is consumed by the F1F0 ATP synthase to partially maintain hPSC mitochondrial membrane potential and cell viability. Uncoupling protein 2 (UCP2) plays a regulating role in hPSC energy metabolism by preventing mitochondrial glucose oxidation and facilitating glycolysis via a substrate shunting mechanism. With early differentiation, hPSC proliferation slows, energy metabolism decreases, and UCP2 is repressed, resulting in decreased glycolysis and maintained or increased mitochondrial glucose oxidation. Ectopic UCP2 expression perturbs this metabolic transition and impairs hPSC differentiation. Overall, hPSCs contain active mitochondria and require UCP2 repression for full differentiation potential. PMID:22085932

  20. An integrative dynamic model of brain energy metabolism using in vivo neurochemical measurements.

    PubMed

    Cloutier, Mathieu; Bolger, Fiachra B; Lowry, John P; Wellstead, Peter

    2009-12-01

    An integrative, systems approach to the modelling of brain energy metabolism is presented. Mechanisms such as glutamate cycling between neurons and astrocytes and glycogen storage in astrocytes have been implemented. A unique feature of the model is its calibration using in vivo data of brain glucose and lactate from freely moving rats under various stimuli. The model has been used to perform simulated perturbation experiments that show that glycogen breakdown in astrocytes is significantly activated during sensory (tail pinch) stimulation. This mechanism provides an additional input of energy substrate during high consumption phases. By way of validation, data from the perfusion of 50 microM propranolol in the rat brain was compared with the model outputs. Propranolol affects the glucose dynamics during stimulation, and this was accurately reproduced in the model by a reduction in the glycogen breakdown in astrocytes. The model's predictive capacity was verified by using data from a sensory stimulation (restraint) that was not used for model calibration. Finally, a sensitivity analysis was conducted on the model parameters, this showed that the control of energy metabolism and transport processes are critical in the metabolic behaviour of cerebral tissue. PMID:19396534

  1. Energy transfer in "parasitic" cancer metabolism: mitochondria are the powerhouse and Achilles' heel of tumor cells.

    PubMed

    Martinez-Outschoorn, Ubaldo E; Pestell, Richard G; Howell, Anthony; Tykocinski, Mark L; Nagajyothi, Fnu; Machado, Fabiana S; Tanowitz, Herbert B; Sotgia, Federica; Lisanti, Michael P

    2011-12-15

    It is now widely recognized that the tumor microenvironment promotes cancer cell growth and metastasis via changes in cytokine secretion and extracellular matrix remodeling. However, the role of tumor stromal cells in providing energy for epithelial cancer cell growth is a newly emerging paradigm. For example, we and others have recently proposed that tumor growth and metastasis is related to an energy imbalance. Host cells produce energy-rich nutrients via catabolism (through autophagy, mitophagy, and aerobic glycolysis), which are then transferred to cancer cells to fuel anabolic tumor growth. Stromal cell-derived L-lactate is taken up by cancer cells and is used for mitochondrial oxidative phosphorylation (OXPHOS) to produce ATP efficiently. However, "parasitic" energy transfer may be a more generalized mechanism in cancer biology than previously appreciated. Two recent papers in Science and Nature Medicine now show that lipolysis in host tissues also fuels tumor growth. These studies demonstrate that free fatty acids produced by host cell lipolysis are re-used via beta-oxidation (beta-OX) in cancer cell mitochondria. Thus, stromal catabolites (such as lactate, ketones, glutamine and free fatty acids) promote tumor growth by acting as high-energy onco-metabolites. As such, host catabolism, via autophagy, mitophagy and lipolysis, may explain the pathogenesis of cancer-associated cachexia and provides exciting new druggable targets for novel therapeutic interventions. Taken together, these findings also suggest that tumor cells promote their own growth and survival by behaving as a "parasitic organism." Hence, we propose the term "Parasitic Cancer Metabolism" to describe this type of metabolic coupling in tumors. Targeting tumor cell mitochondria (OXPHOS and beta-OX) would effectively uncouple tumor cells from their hosts, leading to their acute starvation. In this context, we discuss new evidence that high-energy onco-metabolites (produced by the stroma) can confer drug resistance. Importantly, this metabolic chemo-resistance is reversed by blocking OXPHOS in cancer cell mitochondria with drugs like Metformin, a mitochondrial "poison." In summary, parasitic cancer metabolism is achieved architecturally by dividing tumor tissue into at least two well-defined opposing "metabolic compartments:" catabolic and anabolic. PMID:22033146

  2. Identification and characterization of an anaerobic ethanol-producing cellulolytic bacterial consortium from Great Basin hot springs with agricultural residues and energy crops.

    PubMed

    Zhao, Chao; Deng, Yunjin; Wang, Xingna; Li, Qiuzhe; Huang, Yifan; Liu, Bin

    2014-09-01

    In order to obtain the cellulolytic bacterial consortia, sediments from Great Basin hot springs (Nevada, USA) were sampled and enriched with cellulosic biomass as the sole carbon source. The bacterial composition of the resulting anaerobic ethanol-producing celluloytic bacterial consortium, named SV79, was analyzed. With methods of the full-length 16S rRNA librarybased analysis and denaturing gradient gel electrophoresis, 21 bacteria belonging to eight genera were detected from this consortium. Clones with closest relation to the genera Acetivibrio, Clostridium, Cellulosilyticum, Ruminococcus, and Sporomusa were predominant. The cellulase activities and ethanol productions of consortium SV79 using different agricultural residues (sugarcane bagasse and spent mushroom substrate) and energy crops (Spartina anglica, Miscanthus floridulus, and Pennisetum sinese Roxb) were studied. During cultivation, consortium SV79 produced the maximum filter paper activity (FPase, 9.41 U/ml), carboxymethylcellulase activity (CMCase, 6.35 U/ml), and xylanase activity (4.28 U/ml) with sugarcane bagasse, spent mushroom substrate, and S. anglica, respectively. The ethanol production using M. floridulus as substrate was up to 2.63 mM ethanol/g using gas chromatography analysis. It has high potential to be a new candidate for producing ethanol with cellulosic biomass under anoxic conditions in natural environments. PMID:24809291

  3. Microbial population dynamics during startup of a full-scale anaerobic digester treating industrial food waste in Kyoto eco-energy project.

    PubMed

    Ike, Michihiko; Inoue, Daisuke; Miyano, Tomoki; Liu, Tong Tong; Sei, Kazunari; Soda, Satoshi; Kadoshin, Shiro

    2010-06-01

    The microbial community in a full-scale anaerobic digester (2300m3) treating industrial food waste in the Kyoto Eco-Energy Project was analyzed using terminal restriction fragment length polymorphism for eubacterial and archaeal 16S rRNA genes. Both thermophilic and mesophilic sludge of treated swine waste were seeded to the digestion tank. During the 150-day startup period, coffee grounds as a main food waste, along with potato, kelp and boiled beans, tofu, bean curd lees, and deep-fried bean curd were fed to the digestion process step-by-step (max. 40t/d). Finally, the methane yield reached 360m3/t-feed with 40days' retention time, although temporary accumulation of propionate was observed. Eubacterial communities that formed in the thermophilic digestion tank differed greatly from both thermophilic and mesophilic types of seed sludge. Results suggest that the Actinomyces/Thermomonospora and Ralstonia/Shewanella were contributors for hydrolyzation and degradation of food waste into volatile fatty acids. Acetate-utilizing methanogens, Methanosaeta, were dominant in seed sludges of both types, but they decreased drastically during processing in the digestion tank. Methanosarcina and Methanobrevibacter/Methanobacterium were, respectively, possible main contributors for methane production from acetate and H2 plus CO2. PMID:20129780

  4. Improvement of anaerobic digestion of sewage sludge in a wastewater treatment plant by means of mechanical and thermal pre-treatments: Performance, energy and economical assessment.

    PubMed

    Ruffino, Barbara; Campo, Giuseppe; Genon, Giuseppe; Lorenzi, Eugenio; Novarino, Daniel; Scibilia, Gerardo; Zanetti, Mariachiara

    2014-10-22

    Performances of mechanical and low-temperature (<100°C) thermal pre-treatments were investigated to improve the present efficiency of anaerobic digestion (AD) carried out on waste activated sludge (WAS) in the largest Italian wastewater treatment plant (2,300,000p.e.). Thermal pre-treatments returned disintegration rates of one order of magnitude higher than mechanical ones (about 25% vs. 1.5%). The methane specific production increased by 21% and 31%, with respect to untreated samples, for treatment conditions of respectively 70 and 90°C, 3h. Thermal pre-treatments also decreased WAS viscosity. Preliminary energy and economic assessments demonstrated that a WAS final total solid content of 5% was enough to avoid the employment of auxiliary methane for the pre-treatment at 90°C and the subsequent AD process, provided that all the heat generated was transferred to WAS through heat exchangers. Moreover, the total revenues from sale of the electricity produced from biogas increased by 10% with respect to the present scenario. PMID:25459836

  5. Solar heated anaerobic digester

    Microsoft Academic Search

    Rhoades

    1980-01-01

    The title digester is adapted to utilize organic waste material capable of decomposing to produce CHâ and a liquid fertilizer. The sealed anaerobic digester is wrapped with a layer of heat-absorptive material followed by a series of abutting removable panels of insulative material. Insulative panels may be temporarily removed to expose the heat-absorptive material to solar radiation and may be

  6. Repeated Anaerobic Microbial Redox Cycling of Iron?†

    PubMed Central

    Coby, Aaron J.; Picardal, Flynn; Shelobolina, Evgenya; Xu, Huifang; Roden, Eric E.

    2011-01-01

    Some nitrate- and Fe(III)-reducing microorganisms are capable of oxidizing Fe(II) with nitrate as the electron acceptor. This enzymatic pathway may facilitate the development of anaerobic microbial communities that take advantage of the energy available during Fe-N redox oscillations. We examined this phenomenon in synthetic Fe(III) oxide (nanocrystalline goethite) suspensions inoculated with microflora from freshwater river floodplain sediments. Nitrate and acetate were added at alternate intervals in order to induce repeated cycles of microbial Fe(III) reduction and nitrate-dependent Fe(II) oxidation. Addition of nitrate to reduced, acetate-depleted suspensions resulted in rapid Fe(II) oxidation and accumulation of ammonium. High-resolution transmission electron microscopic analysis of material from Fe redox cycling reactors showed amorphous coatings on the goethite nanocrystals that were not observed in reactors operated under strictly nitrate- or Fe(III)-reducing conditions. Microbial communities associated with N and Fe redox metabolism were assessed using a combination of most-probable-number enumerations and 16S rRNA gene analysis. The nitrate-reducing and Fe(III)-reducing cultures were dominated by denitrifying Betaproteobacteria (e.g., Dechloromonas) and Fe(III)-reducing Deltaproteobacteria (Geobacter), respectively; these same taxa were dominant in the Fe cycling cultures. The combined chemical and microbiological data suggest that both Geobacter and various Betaproteobacteria participated in nitrate-dependent Fe(II) oxidation in the cycling cultures. Microbially driven Fe-N redox cycling may have important consequences for both the fate of N and the abundance and reactivity of Fe(III) oxides in sediments. PMID:21742920

  7. Swimming performance and energy metabolism of rainbow trout, common carp and gibel carp respond differently to sublethal copper exposure.

    PubMed

    De Boeck, G; van der Ven, K; Hattink, J; Blust, R

    2006-10-25

    We compared the effects of sublethal waterborne copper exposure on swimming performance and respiration rates in rainbow trout, Oncorhynchus mykiss, with those in less sensitive cyprinid species such as common carp, Cyprinus carpio, and gibel carp, Carassius auratus gibelio. These cyprinids are considerably more resistant to Cu intoxication, and differ from trout in swimming performance and respiratory behaviour. Critical swimming speed (U(crit)), oxygen consumption, plasma ammonia and muscle ammonia, lactate and pH were measured during a 28-day sublethal exposure to 1 microM Cu. U(crit) decreased with 48, 31 and 13% within the first 12-24 h for rainbow trout, common and gibel respectively. Gibel carp recovered quickly and experienced no further reduction in swimming performance. Recovery of swimming capacity in rainbow trout and common carp was only partial. All three species displayed similar plasma ammonia peaks in the first hours to days, and a more gradual muscle ammonia accumulation over time. Whereas no signs of respiratory stress occurred in rainbow trout, common carp experienced a transient reduction in oxygen consumption combined with anaerobic metabolism after 24 h of exposure. At the same time, oxygen consumption was also reduced in gibel carp, but no signs of anaerobic metabolism were detected. Cu accumulated quickly to similar levels (36-39 microg g(-1) dry weight at day 3) in the gills of all three species, after which accumulation leveled off. Liver tissue of rainbow trout had a high Cu level from the start, and Cu concentration did not show any additional accumulation. In contrast, common carp liver showed a significant Cu accumulation from day 3 onwards, while accumulation in gibel livers was much slower and was significant from day 7 onwards. Interestingly, Cu accumulation patterns in plasma and kidney revealed a possibly important role for the kidney in Cu homeostasis of gibel carp. PMID:16956679

  8. Gene and protein expression profiles of Shewanella oneidensis during anaerobic growth with different electron acceptors.

    SciTech Connect

    Beliaev, A. S.; Thompson, D. K.; Khare, T.; Lim, H.; Brandt, C. C.; Li, G.; Murray, A. E.; Heidelberg, J. F.; Giometti, C. S.; Yates, J., III; Nealson, K. H.; Tiedje, J. M.; Zhou, J.; Biosciences Division; ORNL; Scripps Research Inst.; Michigan State Univ.; The Inst. for Genomic Research; Jet Propulsion Laboratory; California Inst. of Tech.

    2002-01-01

    Changes in mRNA and protein expression profiles of Shewanella oneidenesis MR-1 during switch from aerobic to fumarate-, Fe(III)-, or nitrate-reducing conditions were examined using DNA microarrays and two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). In response to changes in growth conditions, 121 of the 691 arrayed genes displayed at least a two-fold difference in transcript abundance as determined by microarray analysis. Genes involved in aerobic respiration encoding cytochrome c and d oxidases and TCA cycle enzymes were repressed under anaerobic conditions. Genes induced during anaerobic respiration included those involved in cofactor biosynthesis and assembly (moaACE, ccmHF, nosD, cysG), substrate transport (cysUP, cysTWA, dcuB), and anaerobic energy metabolism (dmsAB, psrC, pshA, hyaABC, hydA). Transcription of genes encoding a periplasmic nitrate reductase (napBHGA), cytochrome c{sub 552}, and prismane was elevated 8- to 56-fold in response to the presence of nitrate, while cymA, ifcA, and frdA were specifically induced three- to eightfold under fumarate-reducing conditions. The mRNA levels for two oxidoreductase-like genes of unknown function and several cell envelope genes involved in multidrug resistance increased two- to fivefold specifically under Fe(III)-reducing conditions. Analysis of protein expression profiles under aerobic and anaerobic conditions revealed 14 protein spots that showed significant differences in abundance on 2-D gels. Protein identification by mass spectrometry indicated that the expression of prismane, dihydrolipoamide succinyltransferase, and alcaligin siderophore biosynthesis protein correlated with the microarray data.

  9. A proteomic study of Shengmai injection's mechanism on preventing cardiac ischemia-reperfusion injury via energy metabolism modulation.

    PubMed

    Zhan, Shuyu; Fan, Xiaohui; Zhang, Feng; Wang, Yi; Kang, Liyuan; Li, Zheng

    2015-02-01

    Energy metabolism modulation plays an important role in protecting the heart from ischemia-reperfusion (IR) injury. Shengmai injection (SMI) is a Chinese medicine, which is widely used in China to treat ischemic heart diseases with speculated functions of modulating energy metabolism. To uncover the molecular mechanisms underlying the cardioprotective activity of SMI via the modulation of energy metabolism, a proteomic analysis was performed on ischemia-reperfusion (IR) injured hearts of rats in this study. Two-dimensional gel electrophoresis (2-DE) was used to measure the protein expression profiles of heart tissues. Differentially expressed proteins among groups were identified using matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS/MS). Western blot analysis was used to validate differentially expressed proteins. Proteomic data revealed 14 major differentially expressed proteins that are related to the energy metabolism. It was found that the glucose oxidation, TCA cycle and ATP synthesis related proteins were consistently up-regulated in SMI treated rats, which is beneficial to aerobic respiration and ATP generation. In contrast, two proteins catalyzing fatty acid ?-oxidation were down-regulated, implying the inhibition of this pathway to avoid high oxygen consumption. It is thus concluded that one of the major mechanisms of SMI protection against IR injury was modulation of the myocardial energy metabolism to improve cardiac efficiency through multiple metabolic pathways including stimulating glucose metabolism and inhibiting fatty acid metabolism. It provided potential protein targets for the therapeutic strategy through modulation of the myocardial energy metabolism. PMID:25427756

  10. Mutations in cytoplasmic dynein lead to a Huntington's disease-like defect in energy metabolism of brown and white adipose tissues

    E-print Network

    Paris-Sud XI, Université de

    metabolism of brown and white adipose tissues Judith Eschbach, Anissa Fergani, Hugues Oudart, Jean to a Huntington's disease-like defect in energy metabolism of brown and white adipose tissues, BBA - Molecular in energy metabolism of brown and white adipose tissues Judith ESCHBACH1,2 , Anissa FERGANI1,2 , Hugues

  11. Some unique features of alkaliphilic anaerobes

    NASA Astrophysics Data System (ADS)

    Roof, Erin; Pikuta, Elena; Otto, Christopher; Williams, George; Hoover, Richard

    2013-09-01

    This article explores two topics involving the examination of four strains of alkaliphilic anaerobes. The first topic was dedicated to detection of the ability of microorganisms to metabolize alternative chirality substrates. Two saccharolytic anaerobic bacteria were chosen for the first experiment: Anaerovirgula multivorans strain SCAT, which is gram positive and spore-forming; and Spirochaeta dissipatitropha, strain ASpC2T, which is gram negative. It was found that both checked sugarlytics were able to use L-ribose and L-arabinose, as growth substrates. The second part was concerned of study a chemolithotrophy in two halo-alkaliphilic sulfate reducing bacteria: Desulfonatornum thiodismutans strain MLF1T and Desulfonatronum lacustre strain Z-7951T. The experiments with lithotrophs had demonstrated that strain MLF1T was capable to grow without any organic source of carbon, while strain Z-7951T had required at least 2 mM sodium acetate for growth. Anaerobic technique was used for preparation of the growth media and maintenance of these bacterial cultures. Standard methods for Gram, spore, and flagella staining were applied for characterization of cytomorphology. In this article, the results of the experiments performed on cytological, physiological, and biochemical levels are presented and discussed.

  12. An expanded view of energy homeostasis: Neural integration of metabolic, cognitive, and emotional drives to eat

    PubMed Central

    Shin, Andrew C.; Zheng, Huiyuan; Berthoud, Hans-Rudolf

    2009-01-01

    The traditional view of neural regulation of body energy homeostasis focuses on internal feedback signals integrated in the hypothalamus and brainstem and in turn leading to balanced activation of behavioral, autonomic, and endocrine effector pathways leading to changes in food intake and energy expenditure. Recent observations have demonstrated that many of these internal signals encoding energy status have much wider effects on the brain, particularly sensory and cortico-limbic systems that process information from the outside world by detecting and interpreting food cues, forming, storing, and recalling representations of experience with food, and assigning hedonic and motivational value to conditioned and unconditioned food stimuli. Thus, part of the metabolic feedback from the internal milieu regulates food intake and energy balance by acting on extrahypothalamic structures, leading to an expanded view of neural control of energy homeostasis taking into account the need to adapt to changing conditions in the environment. The realization that metabolic signals act directly on these non-traditional targets of body energy homeostasis brings opportunities for novel drug targets for the fight against obesity and eating disorders. PMID:19419661

  13. Characterization of anaerobic perchloroethylene dehalogenation activity at various substrate and perchloroethylene concentrations

    SciTech Connect

    Shah, M.M.; Gao, J.; Skeen, R.S.; Hooker, B.S. [Pacific Northwest Lab., Richland, WA (United States)

    1995-12-31

    Research was undertaken to characterize anaerobic perchloroethylene (PCE) dehalogenation activity of microorganisms at various substrate and PCE concentrations. The concentrations of substrate, chlorinated ethylenes, and metabolic products such as methane, acetate, propionate, butyrate, hydrogen, and formate were monitored. The apparent relationship between major metabolic activities and dehalogenation was determined.

  14. A link between hepatic glucose production and peripheral energy metabolism via hepatokines

    PubMed Central

    Abdul-Wahed, Aya; Gautier-Stein, Amandine; Casteras, Sylvie; Soty, Maud; Roussel, Damien; Romestaing, Caroline; Guillou, Hervé; Tourette, Jean-André; Pleche, Nicolas; Zitoun, Carine; Gri, Blandine; Sardella, Anne; Rajas, Fabienne; Mithieux, Gilles

    2014-01-01

    Type 2 diabetes is characterized by a deterioration of glucose tolerance, which associates insulin resistance of glucose uptake by peripheral tissues and increased endogenous glucose production. Here we report that the specific suppression of hepatic glucose production positively modulates whole-body glucose and energy metabolism. We used mice deficient in liver glucose-6 phosphatase that is mandatory for endogenous glucose production. When they were fed a high fat/high sucrose diet, they resisted the development of diabetes and obesity due to the activation of peripheral glucose metabolism and thermogenesis. This was linked to the secretion of hepatic hormones like fibroblast growth factor 21 and angiopoietin-like factor 6. Interestingly, the deletion of hepatic glucose-6 phosphatase in previously obese and insulin-resistant mice resulted in the rapid restoration of glucose and body weight controls. Therefore, hepatic glucose production is an essential lever for the control of whole-body energy metabolism during the development of obesity and diabetes. PMID:25061558

  15. Depletion of reduction potential and key energy generation metabolic enzymes underlies tellurite toxicity in Deinococcus radiodurans.

    PubMed

    Anaganti, Narasimha; Basu, Bhakti; Gupta, Alka; Joseph, Daisy; Apte, Shree Kumar

    2015-01-01

    Oxidative stress resistant Deinococcus radiodurans surprisingly exhibited moderate sensitivity to tellurite induced oxidative stress (LD50 = 40 ?M tellurite, 40 min exposure). The organism reduced 70% of 40 ?M potassium tellurite within 5 h. Tellurite exposure significantly modulated cellular redox status. The level of ROS and protein carbonyl contents increased while the cellular reduction potential substantially decreased following tellurite exposure. Cellular thiols levels initially increased (within 30 min) of tellurite exposure but decreased at later time points. At proteome level, tellurite resistance proteins (TerB and TerD), tellurite reducing enzymes (pyruvate dehydrogense subunits E1 and E3), ROS detoxification enzymes (superoxide dismutase and thioredoxin reductase), and protein folding chaperones (DnaK, EF-Ts, and PPIase) displayed increased abundance in tellurite-stressed cells. However, remarkably decreased levels of key metabolic enzymes (aconitase, transketolase, 3-hydroxy acyl-CoA dehydrogenase, acyl-CoA dehydrogenase, electron transfer flavoprotein alpha, and beta) involved in carbon and energy metabolism were observed upon tellurite stress. The results demonstrate that depletion of reduction potential in intensive tellurite reduction with impaired energy metabolism lead to tellurite toxicity in D. radiodurans. PMID:25331933

  16. Degradation of methyl bromide in anaerobic sediments

    USGS Publications Warehouse

    Oremland, R.S.; Miller, L.G.; Strohmaler, F.E.

    1994-01-01

    Methyl bromide (MeBr) was anaerobically degraded in saltmarsh sediments after reaction with sulfide. The product of this nucleophilic substitution reaction was methanethiol, which underwent further chemical and bacterial reactions to form dimethyl sulfide. These two gases appeared transiently during sediment incubations because they were metabolized by methanogenic and sulfate-reducing bacteria. A second, less significant reaction of MeBr was the exchange with chloride, forming methyl chloride, which was also susceptible to attack by sulfide. Incubation of 14C-labeled methyl iodide as an analogue of MeBr resulted in the formation of 14CH4 and 14CO2 and also indicated that sulfate-reducing bacteria as well as methanogens metabolized the methylated sulfur intermediates. These results suggest that exposed sediments with abundant free sulfide, such as coastal salt-marshes, may constitute a sink for atmospheric MeBr.

  17. Effects of transgenic expression of HIV-1 Vpr on lipid and energy metabolism in mice.

    PubMed

    Balasubramanyam, Ashok; Mersmann, Harry; Jahoor, Farook; Phillips, Terry M; Sekhar, Rajagopal V; Schubert, Ulrich; Brar, Baljinder; Iyer, Dinakar; Smith, E O'Brian; Takahashi, Hideko; Lu, Huiyan; Anderson, Peter; Kino, Tomoshige; Henklein, Peter; Kopp, Jeffrey B

    2007-01-01

    HIV infection is associated with abnormal lipid metabolism, body fat redistribution, and altered energy expenditure. The pathogenesis of these complex abnormalities is unclear. Viral protein R (Vpr), an HIV-1 accessory protein, can regulate gene transcription mediated by the glucocorticoid receptor and peroxisome proliferator-activated receptor-gamma and affect mitochondrial function in vitro. To test the hypothesis that expression of Vpr in liver and adipocytes can alter lipid metabolism in vivo, we engineered mice to express Vpr under control of the phosphoenolpyruvate carboxykinase promoter in a tissue-specific and inducible manner and investigated the effects of dietary fat, indinavir, and dexamethasone on energy metabolism and body composition. The transgenic mice expressed Vpr mRNA in white and brown adipose tissues and liver and immunoaffinity capillary electrophoresis revealed that they had free Vpr protein in the plasma. Compared with wild-type (WT) animals, Vpr mice had lower plasma triglyceride levels after 6 wk (P < 0.05) but not after 10 wk of a high-fat diet and lower plasma cholesterol levels after 10 wk of high-fat diet (P < 0.05). Treatment with dexamethasone obviated group differences, whereas indinavir had no significant independent effect on lipids. In the fasted state, Vpr mice had a higher respiratory quotient than WT mice (P < 0.05). These data provide the first in vivo evidence that HIV-1 Vpr expressed at low levels in adipose tissues and liver can 1) circulate in the blood, 2) regulate lipid and fatty acid metabolism, and 3) alter fuel selection for oxidation in the fasted state. PMID:16882932

  18. Free energy generation and transfers from Archaean hydrothermal vents to the first metabolism

    NASA Astrophysics Data System (ADS)

    Simoncini, E.; Kleidon, A.

    2010-12-01

    Dissipative structures are far from equilibrium systems which self - organize, maintaining a certain internal material order and require free energy in order to be conserved. From a geological point of view, thermal gradients were the most abundant sources of free energy on the early Earth. Here we demonstrate how chemical free energy can be produced by a geological process, serpentinization, associated to the electrochemical potential generation in off - axis hydrothermal vents. The basis for chemical free energy generation is the thermal gradient between the crust and the Archean ocean, which is enhanced by the release of latent heat during serpentinization. Power can be extracted from this thermal gradient to generate motion. The convective motion of heated, chemically reduced fluid produces a redox front when in contact with the acidic Archaean ocean, generating electrical energy to be used in chemical reactions. Further, in the presence of porous inorganic, heterogeneous matrices acting as catalysts, self - sustained reaction chains raised. The free energy thus available could be used to allow the possibility for the establishment of first organic auto - catalytic chains. Molecular evolutionary steps from acetyl CoA to RNA-cleavage gave then rise to the first proto-metabolic processes. We use simple models to calculate the maximum rates of power transfer from the thermal gradient to electric energy to estimate the maximum possible rate of chemical free energy generation by this process. The model also takes into account the heterogeneity of the mineral matrix and its capability to catalyze reactions and to adsorb molecules selectively. In conclusion, non equilibrium thermodynamics in combination with maximum power assumptions help us to determine the fundamental limits of how much chemical free energy can be generated from a geothermal heat flux, providing conditions for the emergence of metabolism.

  19. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    USGS Publications Warehouse

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  20. [Postoperative anaerobic sepsis].

    PubMed

    Fichev, G; Poromanski, I; Marina, M

    1997-01-01

    As shown by clinical practice, postoperative anaerobic sepsis is a complication more common than usually thought of or microbiologically verified. The exceptionally difficult microbiological verification, regardless of the fact that original registered transport media are employed, is the underlying cause of obligate non-spore forming microorganisms from hemoculture being demonstrated in four patients only. In all of them Bacteroides fragilis is isolated and identified. Also, in all patients a fully developed clinical picture of sepsis is present along with the characteristic laboratory septic syndrome constellation as well. After pointing out the difficulties in diagnosing "post-operative anaerobic sepsis", and more particularly its verification, emphasis is laid on the clinical and laboratory symptoms presented by the patients, and on the important role played by the SIRS system, contributing greatly to an adequately oriented clinical thinking. PMID:9739848

  1. Work and metabolic patterns of fast and slow twitch skeletal muscle contracting in situ

    Microsoft Academic Search

    Kenneth M. Baldwin; Charles M. Tipton

    1972-01-01

    A study was conducted to compare the work capacity and aerobic and anaerobic metabolic profiles of the fast-twitch tibialis anterior and slow-twitch soleus muscles of the rat stimulated to contractin situ. Results showed that the soleus could sustain greater relative and absolute work levels than the tibialis anterior. Metabolic profiles revealed that the tibialis anterior depended on anaerobic pathways to

  2. Anaerobic Ammonium Oxidation (Anammox)

    Microsoft Academic Search

    C. Ryan Penton

    Anaerobic ammonium oxidation (anammox) is a recently discovered nitrogen removal pathway in natural systems. First found to\\u000a be a significant nitrogen sink in the Black Sea anoxic water column in 2003, anammox has shown to be responsible for as much\\u000a as 79% of N2 production in marine sediments. Little is known concerning the significance of anammox in freshwater systems and

  3. The anaerobic digestion of organic solid wastes

    SciTech Connect

    Hartung, H.A. [Hartung (H.A.), Collingswood, NJ (United States)

    1996-09-01

    Anaerobic digestion offers many advantages in the processing of organic solid wastes, using a closed system to convert the waste to combustible gas and a stabilized organic residue.Odors are contained while digestion removes their source and gas is collected for energy recovery as heat or electricity. The stabilized residue is less than the starting waste by the mass of gas produced, and it can be disposed of by land application, land filling, incineration or composting. The stimulation of digesters and the phenomenon of co-digestion are two ways the performance of anaerobic digesters can be enhanced. Data from farm digesters and municipal wastewater treatment plants illustrate the present venue of the process; laboratory studies of the anaerobic digestion of a variety of solid wastes show that the process can be applied to these materials as well. About two thirds of municipal solid waste is shown to be amenable to anaerobic digestion in a substrate from an active municipal sewage plant digester.

  4. Nuclear receptor/microRNA circuitry links muscle fiber type to energy metabolism

    PubMed Central

    Gan, Zhenji; Rumsey, John; Hazen, Bethany C.; Lai, Ling; Leone, Teresa C.; Vega, Rick B.; Xie, Hui; Conley, Kevin E.; Auwerx, Johan; Smith, Steven R.; Olson, Eric N.; Kralli, Anastasia; Kelly, Daniel P.

    2013-01-01

    The mechanisms involved in the coordinate regulation of the metabolic and structural programs controlling muscle fitness and endurance are unknown. Recently, the nuclear receptor PPAR?/? was shown to activate muscle endurance programs in transgenic mice. In contrast, muscle-specific transgenic overexpression of the related nuclear receptor, PPAR?, results in reduced capacity for endurance exercise. We took advantage of the divergent actions of PPAR?/? and PPAR? to explore the downstream regulatory circuitry that orchestrates the programs linking muscle fiber type with energy metabolism. Our results indicate that, in addition to the well-established role in transcriptional control of muscle metabolic genes, PPAR?/? and PPAR? participate in programs that exert opposing actions upon the type I fiber program through a distinct muscle microRNA (miRNA) network, dependent on the actions of another nuclear receptor, estrogen-related receptor ? (ERR?). Gain-of-function and loss-of-function strategies in mice, together with assessment of muscle biopsies from humans, demonstrated that type I muscle fiber proportion is increased via the stimulatory actions of ERR? on the expression of miR-499 and miR-208b. This nuclear receptor/miRNA regulatory circuit shows promise for the identification of therapeutic targets aimed at maintaining muscle fitness in a variety of chronic disease states, such as obesity, skeletal myopathies, and heart failure. PMID:23676496

  5. Nuclear receptor/microRNA circuitry links muscle fiber type to energy metabolism.

    PubMed

    Gan, Zhenji; Rumsey, John; Hazen, Bethany C; Lai, Ling; Leone, Teresa C; Vega, Rick B; Xie, Hui; Conley, Kevin E; Auwerx, Johan; Smith, Steven R; Olson, Eric N; Kralli, Anastasia; Kelly, Daniel P

    2013-06-01

    The mechanisms involved in the coordinate regulation of the metabolic and structural programs controlling muscle fitness and endurance are unknown. Recently, the nuclear receptor PPAR?/? was shown to activate muscle endurance programs in transgenic mice. In contrast, muscle-specific transgenic overexpression of the related nuclear receptor, PPAR?, results in reduced capacity for endurance exercise. We took advantage of the divergent actions of PPAR?/? and PPAR? to explore the downstream regulatory circuitry that orchestrates the programs linking muscle fiber type with energy metabolism. Our results indicate that, in addition to the well-established role in transcriptional control of muscle metabolic genes, PPAR?/? and PPAR? participate in programs that exert opposing actions upon the type I fiber program through a distinct muscle microRNA (miRNA) network, dependent on the actions of another nuclear receptor, estrogen-related receptor ? (ERR?). Gain-of-function and loss-of-function strategies in mice, together with assessment of muscle biopsies from humans, demonstrated that type I muscle fiber proportion is increased via the stimulatory actions of ERR? on the expression of miR-499 and miR-208b. This nuclear receptor/miRNA regulatory circuit shows promise for the identification of therapeutic targets aimed at maintaining muscle fitness in a variety of chronic disease states, such as obesity, skeletal myopathies, and heart failure. PMID:23676496

  6. Constraints on Energy Intake in Fish: The Link between Diet Composition, Energy Metabolism, and Energy Intake in Rainbow Trout

    PubMed Central

    Saravanan, Subramanian; Schrama, Johan W.; Figueiredo-Silva, A. Claudia; Kaushik, Sadasivam J.; Verreth, Johan A. J.; Geurden, Inge

    2012-01-01

    The hypothesis was tested that fish fed to satiation with iso-energetic diets differing in macronutrient composition will have different digestible energy intakes (DEI) but similar total heat production. Four iso-energetic diets (2×2 factorial design) were formulated having a contrast in i) the ratio of protein to energy (P/E): high (HP/E) vs. low (LP/E) and ii) the type of non-protein energy (NPE) source: fat vs. carbohydrate which were iso-energetically exchanged. Triplicate groups (35 fish/tank) of rainbow trout were hand-fed each diet twice daily to satiation for 6 weeks under non-limiting water oxygen conditions. Feed intake (FI), DEI (kJ kg?0.8 d?1) and growth (g kg?0.8 d?1) of trout were affected by the interaction between P/E ratio and NPE source of the diet (P<0.05). Regardless of dietary P/E ratio, the inclusion of carbohydrate compared to fat as main NPE source reduced DEI and growth of trout by ?20%. The diet-induced differences in FI and DEI show that trout did not compensate for the dietary differences in digestible energy or digestible protein contents. Further, changes in body fat store and plasma glucose did not seem to exert a homeostatic feedback control on DEI. Independent of the diet composition, heat production of trout did not differ (P>0.05). Our data suggest that the control of DEI in trout might be a function of heat production, which in turn might reflect a physiological limit related with oxidative metabolism. PMID:22496852

  7. Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors

    PubMed Central

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

    2014-01-01

    The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive. PMID:24672798

  8. Energy metabolism and biotransformation as endpoints to pre-screen hepatotoxicity using a liver spheroid model

    SciTech Connect

    Xu Jinsheng [Centre for Research in Biomedicine, Faculty of Applied Sciences, University of the West of England, Bristol, Frenchay Campus, Coldharbour Lane, Bristol BS16 1QY (United Kingdom)]. E-mail: jinsheng.xu@uwe.ac.uk; Purcell, Wendy M. [Health and Human Sciences Research Institute, University of Hertfordshire, Hatfield, Herts (United Kingdom)

    2006-10-15

    The current study investigated liver spheroid culture as an in vitro model to evaluate the endpoints relevant to the status of energy metabolism and biotransformation after exposure to test toxicants. Mature rat liver spheroids were exposed to diclofenac, galactosamine, isoniazid, paracetamol, m-dinitrobenzene (m-DNB) and 3-nitroaniline (3-NA) for 24 h. Pyruvate uptake, galactose biotransformation, lactate release and glucose secretion were evaluated after exposure. The results showed that pyruvate uptake and lactate release by mature liver spheroids in culture were maintained at a relatively stable level. These endpoints, together with glucose secretion and galactose biotransformation, were related to and could reflect the status of energy metabolism and biotransformation in hepatocytes. After exposure, all of the test agents significantly reduced glucose secretion, which was shown to be the most sensitive endpoint of those evaluated. Diclofenac, isoniazid, paracetamol and galactosamine reduced lactate release (P < 0.01), but m-DNB increased lactate release (P < 0.01). Diclofenac, isoniazid and paracetamol also reduced pyruvate uptake (P < 0.01), while galactosamine had little discernible effect. Diclofenac, galactosamine, paracetamol and m-DNB also reduced galactose biotransformation (P < 0.01), by contrast, isoniazid did not. The metabolite of m-DNB, 3-NA, which served as a negative control, did not cause significant changes in lactate release, pyruvate uptake or galactose biotransformation. It is concluded that pyruvate uptake, galactose biotransformation, lactate release and glucose secretion can be used as endpoints for evaluating the status of energy metabolism and biotransformation after exposure to test agents using the liver spheroid model to pre-screen hepatotoxicity.

  9. Reduction of nuclear encoded enzymes of mitochondrial energy metabolism in cells devoid of mitochondrial DNA.

    PubMed

    Mueller, Edith E; Mayr, Johannes A; Zimmermann, Franz A; Feichtinger, René G; Stanger, Olaf; Sperl, Wolfgang; Kofler, Barbara

    2012-01-20

    Mitochondrial DNA (mtDNA) depletion syndromes are generally associated with reduced activities of oxidative phosphorylation (OXPHOS) enzymes that contain subunits encoded by mtDNA. Conversely, entirely nuclear encoded mitochondrial enzymes in these syndromes, such as the tricarboxylic acid cycle enzyme citrate synthase (CS) and OXPHOS complex II, usually exhibit normal or compensatory enhanced activities. Here we report that a human cell line devoid of mtDNA (HEK293 ?(0) cells) has diminished activities of both complex II and CS. This finding indicates the existence of a feedback mechanism in ?(0) cells that downregulates the expression of entirely nuclear encoded components of mitochondrial energy metabolism. PMID:22222373

  10. Bone and energy metabolism parameters in professional cyclists during the Giro d'Italia 3-weeks stage race.

    PubMed

    Lombardi, Giovanni; Lanteri, Patrizia; Graziani, Rosa; Colombini, Alessandra; Banfi, Giuseppe; Corsetti, Roberto

    2012-01-01

    Cycling is a not weight-bearing activity and is known to induce bone resorption. Stage races are really strenuous endurance performances affecting the energy homeostasis. The recently highlighted link, in the co-regulation of bone and energy metabolism, demonstrates a central role for the equilibrium between carboxylated and undercarboxylated forms of osteocalcin. Aim of this study was to understand the acute physiological responses to a cycling stage race in terms of bone turnover and energy metabolism and the possible co-regulative mechanisms underlying their relationship. We studied nine professional cyclists engaged in 2011 Giro d'Italia stage race. Pre-analytical and analytical phases tightly followed academic and anti-doping authority's recommendations. Bone and energy metabolism markers (bone alkaline phosphatase, tartrate-resistant acid phosphatase 5b, total and undercarboxylated osteocalcin, leptin and adiponectin) and related hormones (cortisol and testosterone) were measured, by Sandwich Enzyme Immunoassays, at days -1 (pre-race), 12 and 22 during the race. The power output and the energy expenditure (mean and accumulated) were derived and correlated with the biochemical indexes. During the race, bone metabolism showed that an unbalance in behalf of resorption, which is enhanced, occurred along with a relative increase in the concentration of the undercarboxylated form of osteocalcin that was indirectly related to the enhanced energy expenditure, through adipokines modifications, with leptin decrease (high energy consumption) and adiponectin increase (optimization of energy expenditure). The exertion due to heavy effort induced a decrease of cortisol, while testosterone levels resulted unchanged. In conclusion, during a 3-weeks stage race, bone metabolism is pushed towards resorption. A possible relationship between the bone and the energy metabolisms is suggested by the relative correlations among absolute and relative concentrations trends of undercarboxylated OC, adipokines concentrations, BMI, fat mass (%), power output and the derived energy expenditure. PMID:22848709

  11. Bone and Energy Metabolism Parameters in Professional Cyclists during the Giro d’Italia 3-Weeks Stage Race

    PubMed Central

    Lombardi, Giovanni; Lanteri, Patrizia; Graziani, Rosa; Colombini, Alessandra; Banfi, Giuseppe; Corsetti, Roberto

    2012-01-01

    Cycling is a not weight-bearing activity and is known to induce bone resorption. Stage races are really strenuous endurance performances affecting the energy homeostasis. The recently highlighted link, in the co-regulation of bone and energy metabolism, demonstrates a central role for the equilibrium between carboxylated and undercarboxylated forms of osteocalcin. Aim of this study was to understand the acute physiological responses to a cycling stage race in terms of bone turnover and energy metabolism and the possible co-regulative mechanisms underlying their relationship. We studied nine professional cyclists engaged in 2011 Giro d’Italia stage race. Pre-analytical and analytical phases tightly followed academic and anti-doping authority’s recommendations. Bone and energy metabolism markers (bone alkaline phosphatase, tartrate-resistant acid phosphatase 5b, total and undercarboxylated osteocalcin, leptin and adiponectin) and related hormones (cortisol and testosterone) were measured, by Sandwich Enzyme Immunoassays, at days -1 (pre-race), 12 and 22 during the race. The power output and the energy expenditure (mean and accumulated) were derived and correlated with the biochemical indexes. During the race, bone metabolism showed that an unbalance in behalf of resorption, which is enhanced, occurred along with a relative increase in the concentration of the undercarboxylated form of osteocalcin that was indirectly related to the enhanced energy expenditure, through adipokines modifications, with leptin decrease (high energy consumption) and adiponectin increase (optimization of energy expenditure). The exertion due to heavy effort induced a decrease of cortisol, while testosterone levels resulted unchanged. In conclusion, during a 3-weeks stage race, bone metabolism is pushed towards resorption. A possible relationship between the bone and the energy metabolisms is suggested by the relative correlations among absolute and relative concentrations trends of undercarboxylated OC, adipokines concentrations, BMI, fat mass (%), power output and the derived energy expenditure. PMID:22848709

  12. Green energy from marine algae: biogas production and composition from the anaerobic digestion of Irish seaweed species.

    PubMed

    Vanegas, C H; Bartlett, J

    2013-01-01

    Marine algae have emerged as an alternative feedstock for the production of a number of renewable fuels, including biogas. In addition to energy potential, other characteristics make them attractive as an energy source, including their ability to absorb carbon dioxide (CO2), higher productivity rates than land-based crops and the lack of water use or land competition. For Ireland, biofuels from marine algae can play an important role by reducing imports of fossil fuels as well as providing the necessary energy in rural communities. In this study, five potential seaweed species common in Irish waters, Saccorhiza polyschides, Ulva sp., Laminaria digitata, Fucus serratus and Saccharina latissima, were co-digested individually with bovine slurry. Batch reactors of 120ml and 1000ml were set up and incubated at 35 degrees C to investigate their suitability for production of biogas. Digesters fed with S. latissima produced the maximum methane yield (335 ml g volatile solids(-1) (g(VS)(-1) followed by S. polyschides with 255 ml g(VS)(-1). L. digitata produced 246ml g(VS)(-1) and the lowest yields were from the green seaweed Ulva sp. 191ml g(VS)(-1). The methane and CO2 percentages ranged between 50-72% and 10-45%, respectively. The results demonstrated that the seaweed species investigated are good feedstocks candidates for the production of biogas and methane as a source of energy. Their use on a large-scale process will require further investigation to increase yields and reduce production costs. PMID:24350482

  13. Pancreatic exocrine secretion--a measure of the functional capacity of the pancreatic energy metabolism.

    PubMed

    Letko, G; Pohle, T

    1989-01-01

    In studies on the pathogenesis of ischemic cell injury and of other pancreatic diseases the knowledge of the actual pancreatic energy state is an important factor. Therefore, it would be advantageous to have a simple and inexpensive method to determine this parameter and its alterations in the pancreas. At uniform hormonal stimulation, the extent of exocrine pancreatic secretion showed a clear dependence on energy supply in this organ. The degree of pancreatic juice edema formed after bolus injection of cholecystokinin and secretin at ductal occlusion was found to be the most sensitive and reproducible measure of the functional capacity of the pancreatic energy metabolism. While this parameter can be applied to experimental studies, only, the juice volume secreted could be determined under clinical conditions, too. Both parameters of pancreatic secretion were clearly decreased after preceding short-term ischemia and recovered after an adequate interval of reperfusion. PMID:2588744

  14. An Integrative Approach to Energy, Carbon, and Redox Metabolism in the Cyanobacterium Synechocystis sp. PCC 6803. Special Report

    SciTech Connect

    Overbeek, R.

    2003-06-30

    The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp. PCC 6803 especially in interrelated areas of photosynthesis, respiration, and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, Integrated Genomics, Inc., provided detailed bioinformatic analysis of selected functional systems related to carbon and energy generation and utilization, and of the corresponding pathways, functional roles and individual genes to support wet lab experiments by collaborators.

  15. Differential Effects of Tissue-Specific Deletion of BOSS on Feeding Behaviors and Energy Metabolism

    PubMed Central

    Kohyama-Koganeya, Ayako; Kurosawa, Mizuki; Hirabayashi, Yoshio

    2015-01-01

    Food intake and energy metabolism are tightly controlled to maintain stable energy homeostasis and healthy states. Thus, animals detect their stored energy levels, and based on this, they determine appropriate food intake and meal size. Drosophila melanogaster putative G protein-coupled receptor, Bride of sevenless (BOSS) is a highly evolutionarily conserved protein that responds to extracellular glucose levels in order to regulate energy homeostasis. To address how BOSS regulates energy homeostasis, we characterized a boss mutant by assessing its food intake and stored energy levels. Boss mutants exhibited increased food intake but decreased stored triacylglyceride levels. Using boss-GAL4 drivers, we found that boss is expressed in select tissues that are involved in nutrient sensing and food intake, in a subset of neurons in brain and chemosensory organs, in fat body, and in endocrine cells in gut (enteroendocrine cells). Flies with tissue-specific boss knockdowns in these tissues had abnormal stored energy levels and abnormal food intake. These results suggest that BOSS in either neurons or peripheral nutrient-sensing tissues affects energy homeostasis in ways that relate to the sensing of nutrients and regulation of food intake. PMID:26193363

  16. Potential of anaerobic digestion for material recovery and energy production in waste biomass from a poultry slaughterhouse.

    PubMed

    Yoon, Young-Man; Kim, Seung-Hwan; Oh, Seung-Yong; Kim, Chang-Hyun

    2014-01-01

    This study was carried out to assess the material and energy recovery by organic solid wastes generated from a poultry slaughterhouse. In a poultry slaughterhouse involving the slaughtering of 100,000 heads per day, poultry manure & feather from the mooring stage, blood from the bleeding stage, intestine residue from the evisceration stage, and sludge cake from the wastewater treatment plant were discharged at a unit of 0.24, 4.6, 22.8, and 2.2 Mg day(-1), consecutively. The amount of nitrogen obtained from the poultry slaughterhouse was 22.36 kg 1000 head(-1), phosphate and potash were 0.194 kg 1000 head(-1) and 0.459 kg 1000 head(-1), respectively. As regards nitrogen recovery, the bleeding and evisceration stages accounted for 28.0% and 65.8% of the total amount of recovered nitrogen. Energy recovered from the poultry slaughterhouse was 35.4 Nm(3) 1000 head(-1) as CH4. Moreover, evisceration and wastewater treatment stage occupied 88.1% and 7.2% of the total recovered CH4 amount, respectively. PMID:24125794

  17. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

  18. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

  19. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

  20. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

  1. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

  2. Recent developments in anaerobic membrane reactors.

    PubMed

    Stuckey, David C

    2012-10-01

    Anaerobic membrane reactors (AnMBRs) have recently evolved from aerobic MBRs, with the membrane either external or submerged within the reactor, and can achieve high COD removals (~98%) at hydraulic retention times (HRTs) as low as 3 h. Since membranes stop biomass being washed out, they can enhance performance with inhibitory substrates, at psychrophilic/thermophilic temperatures, and enable nitrogen removal via Anammox. Fouling is important, but addition of activated carbon or resins/precipitants can remove soluble microbial products (SMPs)/colloids and enhance flux. Due to their low energy use and solids production, and solids free effluent, they can enhance nutrient and water recycling. Nevertheless, more work is needed to: compare fouling between aerobic and anaerobic systems; determine how reactor operation influences fouling; evaluate the effect of different additives on membrane fouling; determine whether nitrogen removal can be incorporated into AnMBRs; recover methane solubility from low temperatures effluents; and, establish sound mass and energy balances. PMID:22749372

  3. Increasing serotonin concentrations alter calcium and energy metabolism in dairy cows.

    PubMed

    Laporta, Jimena; Moore, Spencer A E; Weaver, Samantha R; Cronick, Callyssa M; Olsen, Megan; Prichard, Austin P; Schnell, Brian P; Crenshaw, Thomas D; Peñagaricano, Francisco; Bruckmaier, Rupert M; Hernandez, Laura L

    2015-07-01

    A 4×4 Latin square design in which varied doses (0, 0.5, 1.0, and 1.5?mg/kg) of 5-hydroxy-l-tryptophan (5-HTP, a serotonin precursor) were intravenously infused into late-lactation, non-pregnant Holstein dairy cows was used to determine the effects of serotonin on calcium and energy metabolism. Infusion periods lasted 4 days, with a 5-day washout between periods. Cows were infused at a constant rate for 1?h each day. Blood was collected pre- and 5, 10, 30, 60, 90, and 120?min post-infusion, urine was collected pre- and post-infusion, and milk was collected daily. All of the 5-HTP doses increased systemic serotonin as compared to the 0?mg/kg dose, and the 1.0 and 1.5?mg/kg doses increased circulating glucose and non-esterified fatty acids (NEFA) and decreased beta-hydroxybutyrate (?HBA) concentrations. Treatment of cows with either 1.0 or 1.5?mg/kg 5-HTP doses decreased urine calcium elimination, and the 1.5?mg/kg dose increased milk calcium concentrations. No differences were detected in the heart rates, respiration rates, or body temperatures of the cows; however, manure scores and defecation frequency were affected. Indeed, cows that received 5-HTP defecated more, and the consistency of their manure was softer. Treatment of late-lactation dairy cows with 5-HTP improved energy metabolism, decreased loss of calcium into urine, and increased calcium secretion into milk. Further research should target the effects of increasing serotonin during the transition period to determine any benefits for post-parturient calcium and glucose metabolism. PMID:26099356

  4. Placental metabolic reprogramming: do changes in the mix of energy-generating substrates modulate fetal growth?

    PubMed Central

    ILLSLEY, NICHOLAS P.; CANIGGIA, ISABELLA; ZAMUDIO, STACY

    2014-01-01

    Insufficient oxygen leads to the cessation of growth in favor of cellular survival. Our unique model of high-altitude human pregnancy indicates that hypoxia-induced reductions in fetal growth occur at higher levels of oxygen than previously described. Fetal PO2 is surprisingly high and fetal oxygen consumption unaffected by high altitude, whereas fetal glucose delivery and consumption decrease. Placental delivery of energy-generating substrates to the fetus is thus altered by mild hypoxia, resulting in maintained fetal oxygenation but a relative fetal hypoglycemia. Our data point to this altered mix of substrates as a potential initiating factor in reduced fetal growth, since oxygen delivery is adequate. These data support the existence, in the placenta, of metabolic reprogramming mechanisms, previously documented in tumor cells, whereby HIF-1 stimulates reductions in mitochondrial oxygen consumption at the cost of increased glucose consumption. Decreased oxygen consumption is not due to substrate (oxygen) limitation but rather results from active inhibition of mitochondrial oxygen utilization. We suggest that under hypoxic conditions, metabolic reprogramming in the placenta decreases mitochondrial oxygen consumption and increases anerobic glucose consumption, altering the mix of energy-generating substrates available for transfer to the fetus. Increased oxygen is available to support the fetus, but at the cost of less glucose availability, leading to a hypoglycemia-mediated decrease in fetal growth. Our data suggest that metabolic reprogramming may be an initiating step in the progression to more severe forms of fetal growth restriction and points to the placenta as the pivotal source of fetal programming in response to an adverse intrauterine environment. PMID:19924633

  5. Production, digestion, and hepatic lipid metabolism of dairy cows fed increased energy from fat or concentrate.

    PubMed

    Grum, D E; Drackley, J K; Hansen, L R; Cremin, J D

    1996-10-01

    Eight Holstein cows (mean = 52 DIM) were used in a replicated Latin square design (28-d periods) to determine the effects of source and amount of dietary energy on hepatic lipid metabolism. Diets were 1) low concentrate without supplemental fat (1.6 Mcal of NEI/kg), 2) low concentrate with supplemental fat (1.7 Mcal/kg), 3) high concentrate without supplemental fat (1.7 Mcal/kg), and 4) high concentrate with supplemental fat (1.8 Mcal/kg). Intakes of DM and digestible energy were greatest for diets 2 and 3. Milk production, efficiency, and milk CP production were not different among diets. Milk fat percentage and production were increased by supplemental fat and decreased by high concentrate. Contents of CP, true protein, and casein in milk were decreased by supplemental fat and increased by high concentrate. Digestibility of fatty acids was decreased by either supplemental fat or high concentrate. Concentrations of NEFA and somatotropin in plasma were increased, and concentration of IGF-I was decreased, by supplemental fat; NEFA, BHBA, and IGF-I were decreased by high concentrate. In vitro rates of peroxisomal beta-oxidation and esterification of palmitate and concentrations of total lipid and triglycerides in liver were not different among diets, but glycogen content was increased by high concentrate. The rate of total beta-oxidation of palmitate in liver slices tended to be increased by supplemental fat; total metabolism of palmitate was increased by supplemental fat and tended to be increased by high concentrate. Supplemental fat may affect hepatic lipid metabolism in dairy cows; effects of dietary fat during the periparturient period deserve investigation. PMID:8923255

  6. Mitochondrial Free Ca2+ Levels and Their Effects on Energy Metabolism in Drosophila Motor Nerve Terminals

    PubMed Central

    Ivannikov, Maxim V.; Macleod, Gregory T.

    2013-01-01

    Mitochondrial Ca2+ uptake exerts dual effects on mitochondria. Ca2+ accumulation in the mitochondrial matrix dissipates membrane potential (??m), but Ca2+ binding of the intramitochondrial enzymes accelerates oxidative phosphorylation, leading to mitochondrial hyperpolarization. The levels of matrix free Ca2+ ([Ca2+]m) that trigger these metabolic responses in mitochondria in nerve terminals have not been determined. Here, we estimated [Ca2+]m in motor neuron terminals of Drosophila larvae using two methods: the relative responses of two chemical Ca2+ indicators with a 20-fold difference in Ca2+ affinity (rhod-FF and rhod-5N), and the response of a low-affinity, genetically encoded ratiometric Ca2+ indicator (D4cpv) calibrated against known Ca2+ levels. Matrix pH (pHm) and ??m were monitored using ratiometric pericam and tetramethylrhodamine ethyl ester probe, respectively, to determine when mitochondrial energy metabolism was elevated. At rest, [Ca2+]m was 0.22 ± 0.04 ?M, but it rose to ?26 ?M (24.3 ± 3.4 ?M with rhod-FF/rhod-5N and 27.0 ± 2.6 ?M with D4cpv) when the axon fired close to its endogenous frequency for only 2 s. This elevation in [Ca2+]m coincided with a rapid elevation in pHm and was followed by an after-stimulus ??m hyperpolarization. However, pHm decreased and no ??m hyperpolarization was observed in response to lower levels of [Ca2+]m, up to 13.1 ?M. These data indicate that surprisingly high levels of [Ca2+]m are required to stimulate presynaptic mitochondrial energy metabolism. PMID:23746507

  7. Metabolic imprinting: critical impact of the perinatal environment on the regulation of energy homeostasis

    PubMed Central

    Levin, Barry E

    2006-01-01

    Epidemiological studies in humans suggest that maternal undernutrition, obesity and diabetes during gestation and lactation can all produce obesity in offspring. Animal models have allowed us to investigate the independent consequences of altering the pre- versus post-natal environments on a variety of metabolic, physiological and neuroendocrine functions as they effect the development in the offspring of obesity, diabetes, hypertension and hyperlipidemia (the ‘metabolic syndrome’). During gestation, maternal malnutrition, obesity, type 1 and type 2 diabetes and psychological, immunological and pharmacological stressors can all promote offspring obesity. Normal post-natal nutrition can reduce the adverse impact of some of these pre-natal factors but maternal high-fat diets, diabetes and increased neonatal access to food all enhance the development of obesity and the metabolic syndrome in offspring. The outcome of these perturbations of the perinatal environmental is also highly dependent upon the genetic background of the individual. Those with an obesity-prone genotype are more likely to be affected by factors such as maternal obesity and high-fat diets than are obesity-resistant individuals. Many perinatal manipulations appear to promote offspring obesity by permanently altering the development of central neural pathways, which regulate food intake, energy expenditure and storage. Given their strong neurotrophic properties, either excess or an absence of insulin and leptin during the perinatal period are likely to be effectors of these developmental changes. Because obesity is associated with an increased morbidity and mortality and because of its resistance to treatment, prevention is likely to be the best strategy for stemming the tide of the obesity epidemic. Such prevention should begin in the perinatal period with the identification and avoidance of factors which produce permanent, adverse alterations in neural pathways which control energy homeostasis. PMID:16815795

  8. Temporal relation between energy metabolism and myocardial function during ischemia and reperfusion

    SciTech Connect

    Clarke, K.; O'Connor, A.J.; Willis, R.J. (Griffith Univ., Nathan (Australia))

    1987-08-01

    The purpose of the present investigation was to study the relation between energy metabolism and contractile function in the isovolumic guinea pig heart. {sup 31}P nuclear magnetic resonance spectroscopy was used to measure changes in the intracellular levels of creatine phosphate, ATP, inorganic phosphate, and pH during 2.43 min total global ischemia and 2.43 min reperfusion, with a time resolution of 9.7 s. From these data, cytosolic changes in the phosphorylation potential, (ATP)-to-(ADP) ratio, free-energy change of ATP hydrolysis, and concentration of free ADP were estimated. The simultaneous monitoring of functional and biochemical parameters allowed them to be directly correlated with respect to time and with respect to each other. No significant changes in ATP were detected at any time, but changes in all other biochemical data were highly correlated with changes in contractile function. Kinetic analysis, using a nonlinear least-squares fit of the experimental points, revealed that the changes in most parameters fitted monoexponential functions. Each parameter was ranked according to its half time, which revealed that (1) the phosphorylation potential was the only metabolic parameter to change at a rate faster than loss of contractile function during ischemia, and (2) all metabolic changes, with the exception of pH, led the recovery of contractile function during reperfusion, the most rapid change occurring in the free ADP concentration. It is concluded that the cytosolic phosphorylation potential controls the contractile function of the heart and that cytosolic free ADP is important in the control of mitochondrial oxidative phosphorylation.

  9. Effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose.

    PubMed

    Kobayashi, Fumi; Ogata, Hitomi; Omi, Naomi; Nagasaka, Shoichiro; Yamaguchi, Sachiko; Hibi, Masanobu; Tokuyama, Kumpei

    2014-01-01

    Epidemiological studies suggest an association between breakfast skipping and body weight gain, insulin resistance or type 2 diabetes. Time when meal is consumed affects postprandial increase in energy expenditure and blood glucose, and breakfast skipping may reduce 24 h energy expenditure and elevate blood glucose level. The present study evaluated the effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose. The skipped breakfast was compensated by following big meals at lunch and supper. In a randomized repeated-measure design with or without breakfast, eight males stayed twice in a room-size respiratory chamber. Blood glucose was recorded with a continuous glucose monitoring system. Breakfast skipping did not affect 24 h energy expenditure, fat oxidation and thermic effect of food, but increased overall 24 h average of blood glucose (83 ± 3 vs 89 ± 2 mg/dl, P < 0.05). Unlike 24 h glucose level, 24 h energy expenditure was robust when challenged by breakfast skipping. These observations suggest that changes in glucose homeostasis precede that of energy balance, in the potential sequence caused by breakfast skipping, if this dietary habit has any effect on energy balance.: PMID:24847666

  10. Hog farm in California uses anaerobic digestion

    SciTech Connect

    Swanson, D. [Western Area Power Administration, Golden, CO (United States)

    1995-12-31

    This article describes a system of covered lagoons which help address the waste management problems of hog farmers as well as producing methane used to power generators. Four advantages of anaerobic digestion are described along with the system: energy production from methane; fertilizer for fields; economic development in rural areas; and improved water quality through reduction of nonpoint source pollution. Address for full report is given.

  11. Effect of community structure on the kinetics of anaerobic degradation of aromatic compounds. Progress report, March 1989--June 1991

    SciTech Connect

    McInerney, M.J.

    1991-06-01

    The physiology of fatty acid metabolism and the kinetics of benzoate degradation by anaerobic syntrophic bacteria were studied. We have shown that: a threshold for benzoate degradation by a syntrophic coculture of Syntrophus buswellii and Desulfovibrio strain G11 exists and the value of the threshold depends on the amount of benzoate and acetate suggesting a thermodynamic limitation. Syntrophomonas wolfei has the enzymatic ability to produce formate and that low levels of formate are made during growth in pure culture with crotonate or in coculture with butyrate. However, the high specific activities of hydrogenase compared to formate dehydrogenase indicate that hydrogen rather than formate is the intermediate involved in the interspecies transfer of reducing equivalents. We have isolated Syntrophus buswellii and a novel anaerobic bacteria that catalyzes an aryl-ether cleavage reaction using crotonate as the energy source. Several novel obligately halophilic anaerobes from hypersaline oil reservoir brines were isolated and characterized. Two of these degraded pyrogallate with the production of acetate. We have shown that S. wolfei synthesizes poly-{beta}hydroxyalkanoate (PHA) by two routes, directly from a {beta}-oxidation intermediate without cleaving a C-C bond and by the condensation of two acetyl-CoA molecules. The formation of D-3-hydroxyacyl-CoA needed for PHA synthesis occurs by the activity of a acetoacetyl-CoA reductase rather than a enoyl-CoA hydratase. The genes for PHA synthesis in S. wolfei have been cloned into Escherichia coli.

  12. [Immunomodulating activity of polyunsaturated phospholipids and regulators of energy metabolism in toxic anemia].

    PubMed

    Lazareva, G A; Brovkina, I L

    2004-01-01

    Possible potentiation of the immunomodulating effects of carbohydrate and lipid metabolism regulators by their use in combination with polyunsaturated phospholipids was studied. The polyunsaturated phospholipids in toxic anemia icreased the immunomodulating effects of thiamine and inosine which activated glucose catabolism in erythrocytes. The combined use of the polyunsaturated phospholipids and thiamine normalized the oxidation--energy status and lowered manifestation of the immunosuppressing properties of light erythrocytes in laboratory rats exposed to hemolytic poison. The use of the combination of the polyunsaturated phospholipids and inosine normalized the oxidation--energy status and induced manifestation of the immunomodulating properties in heavy erythrocytes of the poisoned rats. The globulin fraction of the rat serum containing antibodies to erythrocytes of the poisoned rats exposed to the polyunsaturated phospholipids and inosine increased the immunity status of the poisoned rats treated with the above mentioned agents. Carnitine and biotin in combination with the polyunsatured phospholipids showed no effect on the phagocytic and metabolic activity of leukocytes and the immunity status of the rats exposed to hemolytic poison. PMID:15573896

  13. Interactions between negative energy balance, metabolic diseases, uterine health and immune response in transition dairy cows.

    PubMed

    Esposito, Giulia; Irons, Pete C; Webb, Edward C; Chapwanya, Aspinas

    2014-01-30

    The biological cycles of milk production and reproduction determine dairying profitability thus making management decisions dynamic and time-dependent. Diseases also negatively impact on net earnings of a dairy enterprise. Transition cows in particular face the challenge of negative energy balance (NEB) and/or disproportional energy metabolism (fatty liver, ketosis, subacute, acute ruminal acidosis); disturbed mineral utilization (milk fever, sub-clinical hypocalcemia); and perturbed immune function (retained placenta, metritis, mastitis). Consequently NEB and reduced dry matter intake are aggravated. The combined effects of all these challenges are reduced fertility and milk production resulting in diminishing profits. Risk factors such as NEB, inflammation and impairment of the immune response are highly cause-and-effect related. Thus, managing cows during the transition period should be geared toward reducing NEB or feeding specially formulated diets to improve immunity. Given that all cows experience a reduced feed intake and body condition, infection and inflammation of the uterus after calving, there is a need for further research on the immunology of transition dairy cows. Integrative approaches at the molecular, cellular and animal level may unravel the complex interactions between disturbed metabolism and immune function that predispose cows to periparturient diseases. PMID:24378117

  14. Phosphate supplementation prevents a decrease of triiodothyronine and increases resting metabolic rate during low energy diet.

    PubMed

    Nazar, K; Kaciuba-U?ci?ko, H; Szczepanik, J; Zemba, A W; Kruk, B; Chwalbi?ska-Moneta, J; Titow-Stupnicka, E; Bicz, B; Krotkiewski, M

    1996-06-01

    Thirty overweight women participated in 8 week slimming program consisting of a self-controlled low-energy diet (4.2 MJ/day) supplemented with highly viscous fibres and mineral tablets containing calcium, potassium and sodium phosphates (Redusan Combi, Biokraft Pharma AB, Sweden). Half of the patients received in double blind manner mineral tablets during first 4 weeks and placebo (without phosphates) during next 4 weeks (group 1) while the remaining patients were treated (cross-over) with placebo first and mineral tablets in the final period (group 2). The rate of weight loss was similar in groups 1 and 2 (4.7 vs 5.2 kg during the first 4 weeks and 2.7 vs 3.0 kg in the further 4 weeks). During periods of phosphate supplementation, the resting metabolic rate (RMR) increased by approx. 12% (p < 0.05) in group 1 and 19% (p < 0.05) in group 2. Phosphate supplementation ameliorated also a decrease in plasma triiodothyronine level and a decrease in thyroxine to triiodothyronine ratio. There were no differences between groups in the plasma insulin, catecholamine, growth hormone, cortisol and testosterone levels. Phosphate supplementation did not affect plasma lipids or blood glucose concentration. It is concluded that phosphate supplementation in obese patients on a low-energy diet enhances RMR irrespectively of the rate of weight loss. This effect seems to be, at least partly, due to an influence of phosphates on peripheral metabolism of thyroid hormones. PMID:8807564

  15. Psychological Stress Alters Ultrastructure and Energy Metabolism of Masticatory Muscle in Rats

    PubMed Central

    Chen, Yong-Jin; Huang, Fei; Zhang, Min; Shang, Hai-Yan

    2010-01-01

    To investigate the effects of psychological stress on the masticatory muscles of rats, a communication box was applied to induce the psychological stress (PS) in rats. The successful establishment of psychological stimulation was confirmed by elevated serum levels of adrenocorticotropic hormone (ACTH) and changed behaviors in the elevated plusmaze apparatus. The energy metabolism of the bilateral masseter muscles was tested via chemocolorimetric analysis, whereas muscle ultrastructure was assessed by electron microscopy. In comparison to the control group, the PS group showed evidence of swollen mitochondria with cristae loss and reduced matrix density in the masticatory muscles after three weeks of stimulation; after five weeks of stimulation, severe vacuolar changes to the mitochondria were observed. Increased vascular permeability of the masticatory muscle capillaries was found in the five-week PS rats. In addition, there was decreased activity of Na+-K+ATPase and Ca2+-ATPase and a simultaneous increase in the activity of lactate dehydrogenase and lactic acid in the masticatory muscles of PS rats. Together, these results indicate that psychological stress induces alterations in the ultrastructure and energy metabolism of masticatory muscles in rats. PMID:21052548

  16. Evolution and significance of the Lon gene family in Arabidopsis organelle biogenesis and energy metabolism

    PubMed Central

    Rigas, Stamatis; Daras, Gerasimos; Tsitsekian, Dikran; Alatzas, Anastasios; Hatzopoulos, Polydefkis

    2014-01-01

    Lon is the first identified ATP-dependent protease highly conserved across all kingdoms. Model plant species Arabidopsis thaliana has a small Lon gene family of four members. Although these genes share common structural features, they have distinct properties in terms of gene expression profile, subcellular targeting and substrate recognition motifs. This supports the notion that their functions under different environmental conditions are not necessarily redundant. This article intends to unravel the biological role of Lon proteases in energy metabolism and plant growth through an evolutionary perspective. Given that plants are sessile organisms exposed to diverse environmental conditions and plant organelles are semi-autonomous, it is tempting to suggest that Lon genes in Arabidopsis are paralogs. Adaptive evolution through repetitive gene duplication events of a single archaic gene led to Lon genes with complementing sets of subfunctions providing to the organism rapid adaptability for canonical development under different environmental conditions. Lon1 function is adequately characterized being involved in mitochondrial biogenesis, modulating carbon metabolism, oxidative phosphorylation and energy supply, all prerequisites for seed germination and seedling establishment. Lon is not a stand-alone proteolytic machine in plant organelles. Lon in association with other nuclear-encoded ATP-dependent proteases builds up an elegant nevertheless, tight interconnected circuit. This circuitry channels properly and accurately, proteostasis and protein quality control among the distinct subcellular compartments namely mitochondria, chloroplasts, and peroxisomes. PMID:24782883

  17. Natural selection reduces energy metabolism in the garden snail, helix aspersa (cornu aspersum).

    PubMed

    Artacho, Paulina; Nespolo, Roberto F

    2009-04-01

    Phenotypic selection is widely recognized as the primary cause of adaptive evolution in natural populations, a fact that has been documented frequently over the last few decades, mainly in morphological and life-history traits. The energetic definition of fitness predicts that natural selection will maximize the residual energy available for growth and reproduction, suggesting that energy metabolism could be a target of selection. To address this problem, we chose the garden snail, Helix aspersa (Cornu aspersum). We performed a seminatural experiment for measuring phenotypic selection on standard metabolic rate (SMR), the minimum cost of maintenance in ectotherm organisms. To discount selection on correlated traits, we included two additional whole-organism performance traits (mean speed and maximum force of dislodgement). We found a combination of linear (negative directional selection, beta=-0.106 +/- 0.06; P= 0.001) and quadratic (stabilizing selection, gamma=-0.012 +/- 0.033; P= 0.061) selection on SMR. Correlational selection was not significant for any possible pair of traits. This suggests that individuals with average-to-reduced SMRs were promoted by selection. To the best of our knowledge, this is the first study showing significant directional selection on the obligatory cost of maintenance in an animal, providing support for the energetic definition of fitness. PMID:19236475

  18. Effects of prolonged sleep deprivation on local rates of cerebral energy metabolism in freely moving rats.

    PubMed

    Everson, C A; Smith, C B; Sokoloff, L

    1994-11-01

    Although sleep deprivation interferes with biological processes essential for performance, health, and longevity, previous studies have failed to reveal any structural or functional changes in brain. We have therefore measured local rates of cerebral glucose utilization (ICMRglc) with the quantitative autoradiographic 2-14C-deoxyglucose method in an effort to determine if and, if so, where sleep deprivation might affect function in sleep-deprived rats. Sleep deprivation was maintained for 11-12 d, long enough to increase whole body energy metabolism, thus confirming that pathophysiological processes that might involve brain functions were evolving. Deep brain temperature was also measured in similarly treated rats and found to be mildly elevated relative to core body temperature. Despite the increased deep brain temperature, systemic hypermetabolism, and sympathetic activation, ICMRglc was not elevated in any of the 60 brain structures examined. Average glucose utilization in the brain as a whole was unchanged in the sleep-deprived rats, but regional decreases were found. The most marked decreases in ICMRglc were in regions of the hypothalamus, thalamus, and limbic system. Mesencephalic and pontine regions were relatively unaffected except for the central gray area. The medulla was entirely normal. The effects of sleep deprivation on brain tended, therefore, to be unidirectional toward decreased energy metabolism, primarily in regions associated with mechanisms of thermoregulation, endocrine regulation, and sleep. Correspondence was found between the hypometabolic brain regions and some aspects of peripheral symptoms. PMID:7965078

  19. Anaerobic degradation of hydroaromatic compounds by newly isolated fermenting bacteria

    Microsoft Academic Search

    Andreas Brune; Berhard Schink

    1992-01-01

    Aerobic organisms degrade hydroaromatic compounds via the hydroaromatic pathway yielding protocatechuic acid which is further metabolized by oxygenase-mediated ring fission in the 3-oxoadipate pathway. No information exists on anaerobic degradation of hydroaromatics so far. We enriched and isolated from various sources of anoxic sediments several strains of rapidly growing gram-negative bacteria fermenting quinic (1,3,4,5-tetrahydroxy-cyclohexane-1-carboxylic acid) and shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid)

  20. Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters

    Microsoft Academic Search

    Lei Zhang; Ping Zheng; Chong-jian Tang; Jin Ren-cun

    2008-01-01

    The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to\\u000a the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable\\u000a in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic\\u000a nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both

  1. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    Microsoft Academic Search

    Jennyfer Miot; Karim Benzerara; Guillaume Morin; Andreas Kappler; Sylvain Bernard; Martin Obst; Céline Férard; Fériel Skouri-Panet; Jean-Michel Guigner; Nicole Posth; Matthieu Galvez; Gordon E. Brown; François Guyot

    2009-01-01

    Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM).

  2. Production of Methane Biogas as Fuel Through Anaerobic Digestion

    Microsoft Academic Search

    Zhongtang Yu; Floyd L. Schanbacher

    \\u000a Anaerobic digestion (AD) is a biotechnology by which biomass is converted by microbes to methane (CH4) biogas, which can then be utilized as a renewable fuel to generate heat and electricity. A genetically and metabolically\\u000a diverse community of microbes (mainly bacteria and methanogens) drives the AD process through a series of complex microbiological\\u000a processes in the absence of oxygen. During

  3. Downregulation of uncoupling protein-3 in vivo is linked to changes in muscle mitochondrial energy metabolism as a result of capsiate administration.

    PubMed

    Faraut, B; Giannesini, B; Matarazzo, V; Marqueste, T; Dalmasso, C; Rougon, G; Cozzone, P J; Bendahan, D

    2007-05-01

    Although it has been suggested that the skeletal muscle mitochondrial uncoupling protein-3 (UCP3) is involved in regulating energy expenditure, its role is still poorly understood. In the present study, we aimed at investigating noninvasively, using magnetic resonance techniques, metabolic changes occurring in exercising muscle as a result of capsiate treatment, which has been previously linked to UCP3 upregulation. We showed that capsiate ingestion strongly reduced UCP3 gene expression in rat gastrocnemius muscle. This large underexpression was accompanied by a significant increase in the rate of mitochondrial ATP production and phosphocreatine level both at rest and during muscle stimulation. Similarly, the stimulation-induced ATP fall and ADP accumulation were significantly less after capsiate administration than in untreated rats. The larger oxidative ATP production rate could not be explained by a proportional decrease in the anaerobic component, i.e., glycolysis and phosphocreatine breakdown. In addition, the mechanical performance was not affected by capsiate administration. Finally, the plasma free fatty acid (FFA) level increased in capsiate-treated rats, whereas no significant change was observed after muscle stimulation in the control group. Considering the corresponding enhanced UCP3 mRNA expression occurring in the control group after muscle stimulation, one can suggest that changes in FFA level and UCP3 mRNA expression are not mechanistically correlated. Overall, we have shown that capsiate administration induced a UCP3 downregulation coupled with an increased mitochondrial ATP synthesis, whereas the muscle force-generating capacity was unchanged. This suggests that a decrease in muscle efficiency and/or additional noncontractile ATP-consuming mechanisms result from UCP3 downregulation. PMID:17264228

  4. The anaerobic oxidation of ammonium

    Microsoft Academic Search

    Mike S. M Jetten; Marc Strous; Katinka T van de Pas-Schoonen; Jos Schalk; Udo G. J. M van Dongen; Astrid A van de Graaf; Susanne Logemann; Gerard Muyzer; Mark C. M van Loosdrecht; J. Gijs Kuenen

    1998-01-01

    From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. `Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH+4 min?1 (mg protein)?1 using

  5. Anaerobic Granular Sludge Bioreactor Technology

    Microsoft Academic Search

    Sharon McHugh; Caroline O'Reilly; Thérèse Mahony; Emer Colleran; Vincent O'Flaherty

    2003-01-01

    Anaerobic digestion is a mature wastewater treatment technology, with worldwide application. The predominantly applied bioreactor designs, such as the upflow anaerobic sludge blanket and expanded granular sludge bed, are based on the spontaneous formation of granular sludge. Despite the exploitation of granular reactors at full-scale for more than two decades, the mechanisms of granulation are not completely understood and numerous

  6. Solar heated anaerobic digester

    SciTech Connect

    Rhoades, D.

    1980-09-09

    The title digester is adapted to utilize organic waste material capable of decomposing to produce CH/sub 4/ and a liquid fertilizer. The sealed anaerobic digester is wrapped with a layer of heat-absorptive material followed by a series of abutting removable panels of insulative material. Insulative panels may be temporarily removed to expose the heat-absorptive material to solar radiation and may be replaced when the solar radiation diminishes. A layer of transparent material wrapped in outwardly spaced relation around the insulating panels is capable of transmitting solar radiation while providing protection against environmental elements. Additional heating means extending into the digester provide auxiliary heat as required.

  7. Effects of Chinese herbal medicine on plasma glucose, protein and energy metabolism in sheep

    PubMed Central

    2013-01-01

    Background The use of antibiotics in animal diets is facing negative feedback due to the hidden danger of drug residues to human health. Traditional Chinese herbal medicine has been used to replace antibiotics in the past two decades and played an increasingly important role in livestock production. The present study was carried out to assess the feeding effects of a traditional nourishing Chinese herbal medicine mixture on kinetics of plasma glucose, protein and energy metabolism in sheep. Ruminal fermentation characteristics were also determined. Methods Four sheep were fed on either mixed hay (MH-diet) or MH-diet supplemented with 2% of Chinese herbal medicine (mixture of Astragalus root, Angelica root and Atractylodes rhizome; CHM-diet) over two 35-day periods using a crossover design. The turnover rate of plasma glucose was measured with an isotope dilution method using [U-13C]glucose. The rates of plasma leucine turnover and leucine oxidation, whole body protein synthesis (WBPS) and metabolic heat production were measured using the [1-13C]leucine dilution and open circuit calorimetry. Results Body weight gain of sheep was higher (P?=?0.03) for CHM-diet than for MH-diet. Rumen pH was lower (P?=?0.02), concentration of rumen total volatile fatty acid tended to be higher (P?=?0.05) and acetate was higher (P?=?0.04) for CHM-diet than for MH-diet. Turnover rates of plasma glucose and leucine did not differ between diets. Oxidation rate of leucine tended to be higher (P?=?0.06) for CHM-diet than for MH-diet, but the WBPS did not differ between diets. Metabolic heat production tended to be greater (P?=?0.05) for CHM-diet than for MH-diet. Conclusions The sheep fed on CHM-diet had a higher body weight gain and showed positive impacts on rumen fermentation and energy metabolism without resulting in any adverse response. Therefore, these results suggested that the Chinese herbal medicine mixture should be considered as a potential feed additive for sheep. PMID:24344643

  8. Effect of Intracellular Expression of Antimicrobial Peptide LL-37 on Growth of Escherichia coli Strain TOP10 under Aerobic and Anaerobic Conditions

    PubMed Central

    Liu, Wei; Dong, Shi Lei; Xu, Fei; Wang, Xue Qin; Withers, T. Ryan

    2013-01-01

    Antimicrobial peptides (AMPs) can cause lysis of target bacteria by directly inserting themselves into the lipid bilayer. This killing mechanism confounds the identification of the intracellular targets of AMPs. To circumvent this, we used a shuttle vector containing the inducible expression of a human cathelicidin-related AMP, LL-37, to examine its effect on Escherichia coli TOP10 under aerobic and anaerobic growth conditions. Induction of LL-37 caused growth inhibition and alteration in cell morphology to a filamentous phenotype. Further examination of the E. coli cell division protein FtsZ revealed that LL-37 did not interact with FtsZ. Moreover, intracellular expression of LL-37 results in the enhanced production of reactive oxygen species (ROS), causing lethal membrane depolarization under aerobic conditions. Additionally, the membrane permeability was increased after intracellular expression of LL37 under both aerobic and anaerobic conditions. Transcriptomic analysis revealed that intracellular LL-37 mainly affected the expression of genes related to energy production and carbohydrate metabolism. More specifically, genes related to oxidative phosphorylation under both aerobic and anaerobic growth conditions were affected. Collectively, our current study demonstrates that intracellular expression of LL-37 in E. coli can inhibit growth under aerobic and anaerobic conditions. While we confirmed that the generation of ROS is a bactericidal mechanism for LL-37 under aerobic growth conditions, we also found that the intracellular accumulation of cationic LL-37 influences the redox and ion status of the cells under both growth conditions. These data suggest that there is a new AMP-mediated bacterial killing mechanism that targets energy metabolism. PMID:23856776

  9. Electrical stimulation of the energy metabolism in yeast cells using a planar Ti-Au-electrode interface.

    PubMed

    Reiher, A; Warnke, C; Radoch, S; Witte, H; Krtschil, A; Mair, T; Müller, S C; Krost, A

    2006-04-01

    We report on the influence of dielectric pulse injection on the energy metabolism of yeast cells with a planar interdigitated electrode interface. The energy metabolism was measured via NADH fluorescence. The application of dielectric pulses results in a distinct decrease of the fluorescence, indicating a response of the energy metabolism of the yeast cells. The reduction of the NADH signal significantly depends on the pulse parameters, i.e., amplitude and width. Furthermore, the interface is used to detect electrical changes in the cell-electrolyte system, arising from glucose-induced oscillations in yeast cells and yeast extract, by dielectric spectroscopy at 10 kHz. These dielectric investigations revealed a beta(1)-dispersion for the system electrolyte/yeast cells as well as for the system electrolyte/yeast extract. In agreement with control measurements we obtained a glycolytic period of 45 s for yeast cells and of 11 min for yeast extract. PMID:17031550

  10. Potassium fluxes, energy metabolism, and oxygenation in intact diabetic rat hearts under normal and stress conditions.

    PubMed

    Jilkina, Olga; Kuzio, Bozena; Kupriyanov, Valery V

    2008-10-01

    We evaluated the function of Na(+)/K(+) ATPase and sarcolemmal K(ATP) channels in diabetic rat hearts. Six weeks after streptozotocin (STZ) injection, unidirectional K(+) fluxes were assayed by using (87)rubidium ((87)Rb(+)) MRS. The hearts were loaded with Rb(+) by perfusion with Krebs-Henseleit buffer, in which 50% of K(+) was substituted with Rb(+). The rate constant of Rb(+) uptake via Na(+)/K(+) ATPase was reduced. K(ATP)-mediated Rb(+) efflux was activated metabolically with 2,4-dinitrophenol (DNP, 50 micromol.L(-1)) or pharmacologically with a K(ATP) channel opener, P-1075 (5 micromol.L(-1)). Cardiac energetics were monitored by using (31)P MRS and optical spectroscopy. DNP produced a smaller ATP decrease, yet similar Rb(+) efflux activation in STZ hearts. In K(+)-arrested hearts, P-1075 had no effect on high-energy phosphates and stimulated Rb(+) efflux by interaction with SUR2A subunit of K(ATP) channel; this stimulation was greater in STZ hearts. In normokalemic hearts, P-1075 caused cardiac arrest and ATP decline, and the stimulation of Rb(+) efflux was lower in normokalemic STZ hearts arrested by P-1075. Thus, the Rb(+)efflux stimulation in STZ hearts was altered depending on the mode of K(ATP) channel activation: pharmacologic stimulation (P-1075) was enhanced, whereas metabolic stimulation (DNP) was reduced. Both the basal concentration of phosphocreatine ([PCr]) and [PCr]/[ATP] were reduced; nevertheless, the STZ hearts were more or equally resistant to metabolic stress. PMID:18841176

  11. New Insights into Dehalococcoides mccartyi Metabolism from a Reconstructed Metabolic Network-Based Systems-Level Analysis of D. mccartyi Transcriptomes

    PubMed Central

    Islam, M. Ahsanul; Waller, Alison S.; Hug, Laura A.; Provart, Nicholas J.; Edwards, Elizabeth A.; Mahadevan, Radhakrishnan

    2014-01-01

    Organohalide respiration, mediated by Dehalococcoides mccartyi, is a useful bioremediation process that transforms ground water pollutants and known human carcinogens such as trichloroethene and vinyl chloride into benign ethenes. Successful application of this process depends on the fundamental understanding of the respiration and metabolism of D. mccartyi. Reductive dehalogenases, encoded by rdhA genes of these anaerobic bacteria, exclusively catalyze organohalide respiration and drive metabolism. To better elucidate D. mccartyi metabolism and physiology, we analyzed available transcriptomic data for a pure isolate (Dehalococcoides mccartyi strain 195) and a mixed microbial consortium (KB-1) using the previously developed pan-genome-scale reconstructed metabolic network of D. mccartyi. The transcriptomic data, together with available proteomic data helped confirm transcription and expression of the majority genes in D. mccartyi genomes. A composite genome of two highly similar D. mccartyi strains (KB-1 Dhc) from the KB-1 metagenome sequence was constructed, and operon prediction was conducted for this composite genome and other single genomes. This operon analysis, together with the quality threshold clustering analysis of transcriptomic data helped generate experimentally testable hypotheses regarding the function of a number of hypothetical proteins and the poorly understood mechanism of energy conservation in D. mccartyi. We also identified functionally enriched important clusters (13 for strain 195 and 11 for KB-1 Dhc) of co-expressed metabolic genes using information from the reconstructed metabolic network. This analysis highlighted some metabolic genes and processes, including lipid metabolism, energy metabolism, and transport that potentially play important roles in organohalide respiration. Overall, this study shows the importance of an organism's metabolic reconstruction in analyzing various “omics” data to obtain improved understanding of the metabolism and physiology of the organism. PMID:24733489

  12. Anaerobic biotransformation of chlorinated alkenes

    SciTech Connect

    Zhuang, P.

    1994-01-01

    Chlorinated alkenes are widely found in contaminated subsurface soil and groundwater. The highly chlorinated alkene (i.e., PCE) is not subject to aerobic biotransformation. The aim of this research was to explore the potential of using anaerobic processes (i.e., denitrification, sulfate-reduction and methanogenesis) for chlorinated alkenes biotransformation. Contaminated soil samples were used throughout this study. Soil microcosms simulating field anoxic conditions with various nutrients amendment, liquid microcosms as well as enrichment liquid cultures were developed to delineate the dechlorination process. The effect of biomass, chlorinated alkenes concentration and site specific conditions (e.g., temperature and pH) on the dechlorination and the primary metabolic process was investigated. The role of sorption and nutritional needs (i.e., electron donor) were also studied. A preliminary study revealed that denitrification was the least affected by low temperatures as compared to sulfate-reduction and methanogenesis. Although dechlorination took place under sequential denitrifying and methanogenic conditions and under sulfate-reducing conditions, further studies concluded that fermentative and methanogenic bacteria were responsible for the observed dechlorination. In most cases, dechlorination of PCE or TCE resulted in the accumulation of cDCE. However, a VC-producing culture was developed from the PCE-contaminated soil. In general, the dechlorination process could be enhanced by increasing electron donor and biomass concentration. At relatively low concentrations, the dechlorination rate was also increased with increasing chlorinated alkene concentration. Dechlorination even proceeded at high chlorinated alkene concentrations when methane production was inhibited. However, as the concentration of the chlorinated alkenes increased, severe toxicity eventually halted the dechlorination process.

  13. Quantitative Metabolomics and Instationary 13C-Metabolic Flux Analysis Reveals Impact of Recombinant Protein Production on Trehalose and Energy Metabolism in Pichia pastoris

    PubMed Central

    Jordà, Joel; Cueto Rojas, Hugo; Carnicer, Marc; Wahl, Aljoscha; Ferrer, Pau; Albiol, Joan

    2014-01-01

    Pichia pastoris has been recognized as an effective host for recombinant protein production. In this work, we combine metabolomics and instationary 13C metabolic flux analysis (INST 13C-MFA) using GC-MS and LC-MS/MS to evaluate the potential impact of the production of a Rhizopus oryzae lipase (Rol) on P. pastoris central carbon metabolism. Higher oxygen uptake and CO2 production rates and slightly reduced biomass yield suggest an increased energy demand for the producing strain. This observation is further confirmed by 13C-based metabolic flux analysis. In particular, the flux through the methanol oxidation pathway and the TCA cycle was increased in the Rol-producing strain compared to the reference strain. Next to changes in the flux distribution, significant variations in intracellular metabolite concentrations were observed. Most notably, the pools of trehalose, which is related to cellular stress response, and xylose, which is linked to methanol assimilation, were significantly increased in the recombinant strain. PMID:24957027

  14. FCPP application to utilize anaerobic digester gas

    SciTech Connect

    Nakayama, Yoshio; Kusama, Nobuyuki; Wada, Katsuya [Toshiba Corp., Tokyo (Japan)

    1996-12-31

    Toshiba and a municipal organization of Yokohama city are jointly conducting a program to utilize ADG (Anaerobic Digester Gas) more effectively. ADG which contains about 60% methane is produced by anaerobic digestion of waste water treatment sludge and has been used as an energy source for heating digestion tanks in sewage treatment plants and/or for combustion engine fuel. This program is focused on operating a commercial Phosphoric Acid Fuel Cell (PAFC) power plant on ADG because of its inherently high fuel efficiency and low emissions characteristics. According to the following joint program, we have successfully demonstrated an ADG fueled FCPP The success of this study promises that the ADG fueled FCPP, an environment-friendly power generation system, will be added to the line-up of PC25{trademark}C applications.

  15. Energy Dense, Protein Restricted Diet Increases Adiposity and Perturbs Metabolism in Young, Genetically Lean Pigs

    PubMed Central

    Fisher, Kimberly D.; Scheffler, Tracy L.; Kasten, Steven C.; Reinholt, Brad M.; van Eyk, Gregory R.; Escobar, Jeffery; Scheffler, Jason M.; Gerrard, David E.

    2013-01-01

    Animal models of obesity and metabolic dysregulation during growth (or childhood) are lacking. Our objective was to increase adiposity and induce metabolic syndrome in young, genetically lean pigs. Pre-pubertal female pigs, age 35 d, were fed a high-energy diet (HED; n?=?12), containing 15% tallow, 35% refined sugars and 9.1–12.9% crude protein, or a control corn-based diet (n?=?11) with 12.2–19.2% crude protein for 16 wk. Initially, HED pigs self-regulated energy intake similar to controls, but by wk 5, consumed more (P<0.001) energy per kg body weight. At wk 15, pigs were subjected to an oral glucose tolerance test (OGTT); blood glucose increased (P<0.05) in control pigs and returned to baseline levels within 60 min. HED pigs were hyperglycemic at time 0, and blood glucose did not return to baseline (P?=?0.01), even 4 h post-challenge. During OGTT, glucose area under the curve (AUC) was higher and insulin AUC was lower in HED pigs compared to controls (P?=?0.001). Chronic HED intake increased (P<0.05) subcutaneous, intramuscular, and perirenal fat deposition, and induced hyperglycemia, hypoinsulinemia, and low-density lipoprotein hypercholesterolemia. A subset of HED pigs (n?=?7) was transitioned back to a control diet for an additional six weeks. These pigs were subjected to an additional OGTT at 22 wk. Glucose AUC and insulin AUC did not improve, supporting that dietary intervention was not sufficient to recover glucose tolerance or insulin production. These data suggest a HED may be used to increase adiposity and disrupt glucose homeostasis in young, growing pigs. PMID:23991090

  16. Cardiac Energy Metabolism and Oxidative Stress Biomarkers in Diabetic Rat Treated with Resveratrol

    PubMed Central

    Carolo dos Santos, Klinsmann; Pereira Braga, Camila; Octavio Barbanera, Pedro; Rodrigues Ferreira Seiva, Fábio; Fernandes Junior, Ary; Fernandes, Ana Angélica Henrique

    2014-01-01

    Resveratrol (RSV), polyphenol from grape, was studied to evaluate its effects on calorimetric parameters, energy metabolism, and antioxidants in the myocardium of diabetic rats. The animals were randomly divided into four groups (n?=?8): C (control group): normal rats; C-RSV: normal rats receiving RSV; DM: diabetic rats; and DM-RSV: diabetics rats receiving RSV. Type 1 diabetes mellitus was induced with administration of streptozotocin (STZ; 60 mg?1 body weight, single dose, i.p.). After 48 hours of STZ administration, the animals received RSV (1.0 mg/kg/day) for gavage for 30 days. Food, water, and energy intake were higher in the DM group, while administration of RSV caused decreases (p<0.05) in these parameters. The glycemia decreased and higher final body weight increased in DM-RSV when compared with the DM group. The diabetic rats showed higher serum-free fatty acid, which was normalized with RSV. Oxygen consumption (VO2) and carbon dioxide production (VCO2) decreased (p<0.05) in the DM group. This was accompanied by reductions in RQ. The C-RSV group showed higher VO2 and VCO2 values. Pyruvate dehydrogenase activity was lower in the DM group and normalizes with RSV. The DM group exhibited higher myocardial ?-hydroxyacyl coenzyme-A dehydrogenase and citrate synthase activity, and RSV decreased the activity of these enzymes. The DM group had higher cardiac lactate dehydrogenase compared to the DM-RSV group. Myocardial protein carbonyl was increased in the DM group. RSV increased reduced glutathione in the cardiac tissue of diabetic animals. The glutathione reductase activity was higher in the DM-RSV group compared to the DM group. In conclusion, diabetes is accompanied by cardiac energy metabolism dysfunction and change in the biomarkers of oxidative stress. The cardioprotective effect may be mediated through RVS's ability to normalize free fatty acid oxidation, enhance utilization glucose, and control the biomarkers' level of oxidative stress under diabetic conditions. PMID:25050809

  17. Mitochondrial Topoisomerase I is Critical for Mitochondrial Integrity and Cellular Energy Metabolism

    PubMed Central

    Douarre, Céline; Sourbier, Carole; Dalla Rosa, Ilaria; Brata Das, Benu; Redon, Christophe E.; Zhang, Hongliang; Neckers, Len; Pommier, Yves

    2012-01-01

    Background Mitochondria contain their own DNA genome (mtDNA), as well as specific DNA replication and protein synthesis machineries. Relaxation of the circular, double-stranded mtDNA relies on the presence of topoisomerase activity. Three different topoisomerases have been identified in mitochondria: Top1mt, Top3? and a truncated form of Top2?. Methodology/Principal Findings The present study shows the importance of Top1mt in mitochondrial homeostasis. Here we show that Top1mt?/? murine embryonic fibroblasts (MEF) exhibit dysfunctional mitochondrial respiration, which leads decreased ATP production and compensation by increased glycolysis and fatty acid oxidation. ROS production in Top1mt?/? MEF cells is involved in nuclear DNA damage and induction of autophagy. Lack of Top1mt also triggers oxidative stress and DNA damage associated with lipid peroxidation and mitophagy in Top1mt?/? mice. Conclusion/Significance Together, our data implicate Top1mt for mitochondrial integrity and energy metabolism. The compensation mechanism described here contributes to the survival of Top1mt?/? cells and mice despite alterations of mitochondrial functions and metabolism. Therefore, this study supports a novel model for cellular adaptation to mitochondrial damage. PMID:22911747

  18. Maximal exercise and muscle energy metabolism after recovery from exercise hyperthermia syndrome.

    PubMed

    Vanuxem, P; Vanuxem, D; Raharison, L; Aubert, M; Pouliquen, G; Deslangles, O

    2001-08-01

    Muscle energy metabolism was studied in 30 subjects after recovery from exercise hyperthermia syndrome (EHTS subjects) and 15 healthy men with identical physical activities. Blood lactate, free fatty acid (FFA), serum creatine kinase activity (CK), and glycerol and the temperature in the auditory duct (T(c)) and on the thumb pad (T(sk)) were measured at rest and during and after maximal exercise on a cycloergometer. The EHTS subjects had a limitation of physical performance, with lowered values for maximal oxygen uptake (VO(2max), P < 0.0005), maximal workload (P < 0.05), and ventilatory threshold (V(t), P < 0.0005). The discrepancy between high plasma concentrations of FFA and the lack of decrease in respiratory ratio (RR) suggests that, in EHTS subjects, a very active release of FFA was not balanced by a proportional increase in catabolism. The increased skin temperature was smaller in EHTS subjects (P < 0.05 at 180 and 200 W). At the end of exercise, auditory duct temperature increase was higher in EHTS subjects than in control subjects (P < 0.05). This study thus showed an impairment of muscle metabolism and an abnormality of thermoregulatory mechanisms. These results may provide insight into the underlying physiopathological disturbance. PMID:11439383

  19. Energy Metabolism in H460 Lung Cancer Cells: Effects of Histone Deacetylase Inhibitors

    PubMed Central

    Amoêdo, Nívea Dias; Rodrigues, Mariana Figueiredo; Pezzuto, Paula; Galina, Antonio; da Costa, Rodrigo Madeiro; de Almeida, Fábio Ceneviva Lacerda; El-Bacha, Tatiana; Rumjanek, Franklin David

    2011-01-01

    Background Tumor cells are characterized by accelerated growth usually accompanied by up-regulated pathways that ultimately increase the rate of ATP production. These cells can suffer metabolic reprogramming, resulting in distinct bioenergetic phenotypes, generally enhancing glycolysis channeled to lactate production. In the present work we showed metabolic reprogramming by means of inhibitors of histone deacetylase (HDACis), sodium butyrate and trichostatin. This treatment was able to shift energy metabolism by activating mitochondrial systems such as the respiratory chain and oxidative phosphorylation that were largely repressed in the untreated controls. Methodology/Principal Findings Various cellular and biochemical parameters were evaluated in lung cancer H460 cells treated with the histone deacetylase inhibitors (HDACis), sodium butyrate (NaB) and trichostatin A (TSA). NaB and TSA reduced glycolytic flux, assayed by lactate release by H460 cells in a concentration dependent manner. NaB inhibited the expression of glucose transporter type 1 (GLUT 1), but substantially increased mitochondria bound hexokinase (HK) activity. NaB induced increase in HK activity was associated to isoform HK I and was accompanied by 1.5 fold increase in HK I mRNA expression and cognate protein biosynthesis. Lactate dehydrogenase (LDH) and pyruvate kinase (PYK) activities were unchanged by HDACis suggesting that the increase in the HK activity was not coupled to glycolytic flux. High resolution respirometry of H460 cells revealed NaB-dependent increased rates of oxygen consumption coupled to ATP synthesis. Metabolomic analysis showed that NaB altered the glycolytic metabolite profile of intact H460 cells. Concomitantly we detected an activation of the pentose phosphate pathway (PPP). The high O2 consumption in NaB-treated cells was shown to be unrelated to mitochondrial biogenesis since citrate synthase (CS) activity and the amount of mitochondrial DNA remained unchanged. Conclusion NaB and TSA induced an increase in mitochondrial function and oxidative metabolism in H460 lung tumor cells concomitant with a less proliferative cellular phenotype. PMID:21789245

  20. The phenomenon of granulation of anaerobic sludge

    Microsoft Academic Search

    L. W. Hulshoff Pol

    1989-01-01

    Successful high-rate anaerobic wastewater treatment can only be accomplished when the slowgrowing anaerobic biomass is efficiently held back in the anaerobic treatment system. This biomass retention can be achieved in various ways including immobilization of the organisms on fixed materials and immobilization on mobile support materials: in the latter case, combined with settling of the anaerobic sludge aggregates.This dissertation focuses

  1. Pseudomonas aeruginosa Anaerobic Respiration in Biofilms

    Microsoft Academic Search

    Sang Sun Yoon; Robert F. Hennigan; George M. Hilliard; Urs A. Ochsner; Kislay Parvatiyar; Moneesha C. Kamani; Holly L. Allen; Teresa R. DeKievit; Paul R. Gardner; Ute Schwab; John J. Rowe; Barbara H. Iglewski; Timothy R. McDermott; Ronald P. Mason; Daniel J. Wozniak; Robert E. W. Hancock; Matthew R. Parsek; Terry L. Noah; Richard C. Boucher; Daniel J. Hassett

    2002-01-01

    Recent data indicate that cystic fibrosis (CF) airway mucus is anaerobic. This suggests that Pseudomonas aeruginosa infection in CF reflects biofilm formation and persistence in an anaerobic environment. P. aeruginosa formed robust anaerobic biofilms, the viability of which requires rhl quorum sensing and nitric oxide (NO) reductase to modulate or prevent accumulation of toxic NO, a byproduct of anaerobic respiration.

  2. Anaerobic granulation technology for wastewater treatment

    Microsoft Academic Search

    Yu Liu; Hai-Lou Xu; Kuan-Yeow Show; Joo-Hwa Tay

    2002-01-01

    Anaerobic wastewater treatment using granular sludge reactors is a developing technology, in which granular sludge is the core component. So far, around 900 anaerobic granular sludge units have been operated worldwide. Although intensive research attention has been given to anaerobic granules in the past 20 years, the mechanisms responsible for anaerobic granulation and the strategy of how to expedite substantially

  3. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, November 1993--November 1994

    SciTech Connect

    McInerney, M.J.

    1994-12-06

    Factors influencing the rate and extent of benzoate degradation by the anaerobic syntrophic consortia were studied. Nonlinear regression analysis showed that the cause of the benzoate threshold was not a diminished benzoate degradation capacity. Analysis of cocultures with hydrogen users that differed in their hydrogen utilization capacities showed that the threshold did not depend on the kinetic properties of the syntrophic partner. These data support a thermodynamic explanation for the threshold, and exclude the possibility that a change in the affinity of the enzyme system due to acetate inhibition caused the threshold. Modeling studies showed that the threshold value could be predicted from the concentrations of the end products, assuming a critical Gibb`s free energy value. This work shows that interspecies acetate transfer is important in controlling the extent of metabolism by syntrophic organisms.

  4. Combining Flux Balance and Energy Balance Analysis for Large-Scale Metabolic Network: Biochemical Circuit Theory for Analysis of Large-Scale Metabolic Networks

    NASA Technical Reports Server (NTRS)

    Beard, Daniel A.; Liang, Shou-Dan; Qian, Hong; Biegel, Bryan (Technical Monitor)

    2001-01-01

    Predicting behavior of large-scale biochemical metabolic networks represents one of the greatest challenges of bioinformatics and computational biology. Approaches, such as flux balance analysis (FBA), that account for the known stoichiometry of the reaction network while avoiding implementation of detailed reaction kinetics are perhaps the most promising tools for the analysis of large complex networks. As a step towards building a complete theory of biochemical circuit analysis, we introduce energy balance analysis (EBA), which compliments the FBA approach by introducing fundamental constraints based on the first and second laws of thermodynamics. Fluxes obtained with EBA are thermodynamically feasible and provide valuable insight into the activation and suppression of biochemical pathways.

  5. Anaerobic Degradation of Uric Acid by Gut Bacteria of Termites †

    PubMed Central

    Potrikus, C. J.; Breznak, John A.

    1980-01-01

    A study was done of anaerobic degradation of uric acid (UA) by representative strains of uricolytic bacteria isolated from guts of Reticulitermes flavipes termites. Streptococcus strain UAD-1 degraded UA incompletely, secreting a fluorescent compound into the medium, unless formate (or a formicogenic compound) was present as a cosubstrate. Formate functioned as a reductant, and its oxidation to CO2 by formate dehydrogenase provided 2H+ + 2e? needed to drive uricolysis to completion. Uricolysis by Streptococcus UAD-1 thus corresponded to the following equation: 1UA + 1formate ? 4CO2 + 1acetate + 4NH3. Urea did not appear to be an intermediate in CO2 and NH3 formation during uricolysis by strain UAD-1. Formate dehydrogenase and uricolytic activities of strain UAD-1 were inducible by growth of cells on UA. Bacteroides termitidis strain UAD-50 degraded UA as follows: 1UA ? 3.5 CO2 + 0.75acetate + 4NH3. Exogenous formate was neither required for nor stimulatory to uricolysis by strain UAD-50. Studies of UA catabolism by Citrobacter strains were limited, because only small amounts of UA were metabolized by cells in liquid medium. Uricolytic activity of such bacteria in situ could be important to the carbon, nitrogen, and energy economy of R. flavipes. PMID:16345588

  6. Isotopic fractionation indicates anaerobic monochlorobenzene biodegradation.

    PubMed

    Kaschl, Arno; Vogt, Carsten; Uhlig, Sylvia; Nijenhuis, Ivonne; Weiss, Holger; Kästner, Matthias; Richnow, Hans H

    2005-06-01

    The concentration and isotopic composition of monochlorobenzene (MCB) was monitored in the plume of an anaerobic, contaminated aquifer in Bitterfeld, Germany. An enrichment in the carbon isotopic composition of more than 4 delta units was found at the fringes of the plume relative to the center (-26.5 %), suggesting the occurrence of in situ biodegradation of MCB. A similar enrichment was measured in a detailed cross-section of the plume and in depth-specific samples obtained in a multilevel sampling well. The latter samples gave a good correlation of MCB concentrations and respective isotopic composition according to the Rayleigh equation. On the other hand, batch experiments using the aerobic MCB-degrading strains Ralstonia sp. DSM 8910, Acidovorax facilis UFZ B517, Rhodococcus erythropolis UFZ B528, and Pseudomonas veronii UFZ B547 showed that the known aerobic pathway initiated by dioxygenases does not result in a significant isotopic fractionation. Thus, a novel anaerobic pathway resulting in an isotopic fractionation appears to be the predominant process of MCB degradation in this aquifer. The study also clearly demonstrates the usefulness of isotopic fractionation analysis to prove biodegradation directly in the field, even when microcosm studies are not available and a metabolic pathway has not yet been elucidated. PMID:16117106

  7. Microbial degradation of lignin-derived compounds under anaerobic conditions

    SciTech Connect

    Colberg, P.J.

    1983-01-01

    Lignin is the second most abundant form of organic carbon in the biosphere. Recent laboratory studies indicate that a large fraction of polymeric lignin is incompletely degraded by aerobic lignolytic microorganisms and is subsequently released as lignin fragments of reduced molecular size. If such lignin-derived compounds become available in the anaerobic environment, they may serve as potential sources of organic carbon for organisms which release methane precursors. The methanogenic bacteria, in turn, serve as terminal members of the anaerobic food chain, and thus, limit the accumulation of organic carbon in anaerobic sinks. This thesis presents evidence to suggest that lignin-derived compounds which have molecular sizes greater than those of single-ring aromatic compounds (MW > 200) are anaerobically biodegradable to methane. This research involved development of selective enrichment cultures capable of utilizing oligolignols as sole carbon sources. Radiolabeled water-soluble catabolites, released during aerobic lignin degradation by the white rot fungus Phanerochaete chrysosporium, were subjected to anaerobic degradation. The second phase of work involved capillary gas chromatographic analyses of enrichment cultures fed a /sup 14/C-labeled, lignin-derived substrate of average molecular weight 600. 2-Bromoethanesulfonic acid was used to inhibit methane formation and enhance buildup of metabolic intermediates, resulting in the accumulation of volatile fatty acids, phenylacetate, benzoate, catechol, 3-phenyl-propionate, vanillin, syringic acid, vanillic acid, ferulic acid, and caffeic acid. A conceptual model for the anaerobic degradation of two- and three-ring lignin fragments is proposed which overlaps both the ferulate and benzoate degradation pathways at the level of single-ring aromatic compounds.

  8. Fermentative degradation of dipicolinic acid (pyridine-2,6-dicarboxylic acid) by a defined coculture of strictly anaerobic bacteria.

    PubMed

    Seyfried, B; Schink, B

    1990-01-01

    Degradation of dipicolinic acid (pyridine-2,6-dicarboxylic acid) under strictly anaerobic conditions was studied in enrichment cultures from marine and freshwater sediments. In all cases, dipicolinic acid was completely degraded. From an enrichment culture from a marine sediment, a defined coculture of two bacteria was isolated. The dipicolinic acid-fermenting bacterium was a Gram-negative, non-sporeforming strictly anaerobic short rod which utilized dipicolinic acid as sole source of carbon, energy, and nitrogen, and fermented it to acetate, propionate, ammonia, and 2CO2. No other substrate was fermented. This bacterium could be cultivated only in coculture with another Gram-negative, non-sporeforming rod from the same enrichment culture which oxidized acetate to CO2 with fumarate, malate, or elemental sulfur as electron acceptor, similar to Desulfuromonas acetoxidans. Since this metabolic activity is not important in substrate degradation by the coculture, the basis of the dependence of the dipicolinic acid-degrading bacterium on the sulfur reducer may be sought in the assimilatory metabolism. PMID:1368138

  9. Incomplete Wood-Ljungdahl pathway facilitates one-carbon metabolism in organohalide-respiring Dehalococcoides mccartyi.

    PubMed

    Zhuang, Wei-Qin; Yi, Shan; Bill, Markus; Brisson, Vanessa L; Feng, Xueyang; Men, Yujie; Conrad, Mark E; Tang, Yinjie J; Alvarez-Cohen, Lisa

    2014-04-29

    The acetyl-CoA "Wood-Ljungdahl" pathway couples the folate-mediated one-carbon (C1) metabolism to either CO2 reduction or acetate oxidation via acetyl-CoA. This pathway is distributed in diverse anaerobes and is used for both energy conservation and assimilation of C1 compounds. Genome annotations for all sequenced strains of Dehalococcoides mccartyi, an important bacterium involved in the bioremediation of chlorinated solvents, reveal homologous genes encoding an incomplete Wood-Ljungdahl pathway. Because this pathway lacks key enzymes for both C1 metabolism and CO2 reduction, its cellular functions remain elusive. Here we used D. mccartyi strain 195 as a model organism to investigate the metabolic function of this pathway and its impacts on the growth of strain 195. Surprisingly, this pathway cleaves acetyl-CoA to donate a methyl group for production of methyl-tetrahydrofolate (CH3-THF) for methionine biosynthesis, representing an unconventional strategy for generating CH3-THF in organisms without methylene-tetrahydrofolate reductase. Carbon monoxide (CO) was found to accumulate as an obligate by-product from the acetyl-CoA cleavage because of the lack of a CO dehydrogenase in strain 195. CO accumulation inhibits the sustainable growth and dechlorination of strain 195 maintained in pure cultures, but can be prevented by CO-metabolizing anaerobes that coexist with D. mccartyi, resulting in an unusual syntrophic association. We also found that this pathway incorporates exogenous formate to support serine biosynthesis. This study of the incomplete Wood-Ljungdahl pathway in D. mccartyi indicates a unique bacterial C1 metabolism that is critical for D. mccartyi growth and interactions in dechlorinating communities and may play a role in other anaerobic communities. PMID:24733917

  10. Incomplete Wood–Ljungdahl pathway facilitates one-carbon metabolism in organohalide-respiring Dehalococcoides mccartyi

    PubMed Central

    Zhuang, Wei-Qin; Yi, Shan; Bill, Markus; Brisson, Vanessa L.; Feng, Xueyang; Men, Yujie; Conrad, Mark E.; Tang, Yinjie J.; Alvarez-Cohen, Lisa

    2014-01-01

    The acetyl-CoA “Wood–Ljungdahl” pathway couples the folate-mediated one-carbon (C1) metabolism to either CO2 reduction or acetate oxidation via acetyl-CoA. This pathway is distributed in diverse anaerobes and is used for both energy conservation and assimilation of C1 compounds. Genome annotations for all sequenced strains of Dehalococcoides mccartyi, an important bacterium involved in the bioremediation of chlorinated solvents, reveal homologous genes encoding an incomplete Wood–Ljungdahl pathway. Because this pathway lacks key enzymes for both C1 metabolism and CO2 reduction, its cellular functions remain elusive. Here we used D. mccartyi strain 195 as a model organism to investigate the metabolic function of this pathway and its impacts on the growth of strain 195. Surprisingly, this pathway cleaves acetyl-CoA to donate a methyl group for production of methyl-tetrahydrofolate (CH3-THF) for methionine biosynthesis, representing an unconventional strategy for generating CH3-THF in organisms without methylene-tetrahydrofolate reductase. Carbon monoxide (CO) was found to accumulate as an obligate by-product from the acetyl-CoA cleavage because of the lack of a CO dehydrogenase in strain 195. CO accumulation inhibits the sustainable growth and dechlorination of strain 195 maintained in pure cultures, but can be prevented by CO-metabolizing anaerobes that coexist with D. mccartyi, resulting in an unusual syntrophic association. We also found that this pathway incorporates exogenous formate to support serine biosynthesis. This study of the incomplete Wood–Ljungdahl pathway in D. mccartyi indicates a unique bacterial C1 metabolism that is critical for D. mccartyi growth and interactions in dechlorinating communities and may play a role in other anaerobic communities. PMID:24733917

  11. Hypothalamus-adipose tissue crosstalk: neuropeptide Y and the regulation of energy metabolism

    PubMed Central

    2014-01-01

    Neuropeptide Y (NPY) is an orexigenic neuropeptide that plays a role in regulating adiposity by promoting energy storage in white adipose tissue and inhibiting brown adipose tissue activation in mammals. This review describes mechanisms underlying NPY’s effects on adipose tissue energy metabolism, with an emphasis on cellular proliferation, adipogenesis, lipid deposition, and lipolysis in white adipose tissue, and brown fat activation and thermogenesis. In general, NPY promotes adipocyte differentiation and lipid accumulation, leading to energy storage in adipose tissue, with effects mediated mainly through NPY receptor sub-types 1 and 2. This review highlights hypothalamus-sympathetic nervous system-adipose tissue innervation and adipose tissue-hypothalamus feedback loops as pathways underlying these effects. Potential sources of NPY that mediate adipose effects include the bloodstream, sympathetic nerve terminals that innervate the adipose tissue, as well as adipose tissue-derived cells. Understanding the role of central vs. peripherally-derived NPY in whole-body energy balance could shed light on mechanisms underlying the pathogenesis of obesity. This information may provide some insight into searching for alternative therapeutic strategies for the treatment of obesity and associated diseases. PMID:24959194

  12. Anaerobic treatment of aircraft deicing wastes: A technology assessment. Final report

    SciTech Connect

    NONE

    1998-09-01

    The work contained in the study documents the fact that deicing wastes containing ethylene glycol (EG) and propylene glycol (PG) may be effectively treated using an anaerobic biological process. In the report, the treatment of aircraft deicing wastes under anaerobic methanogenic conditions is examined in detail. The major project tasks were: airport sampling to define the characteristics of waste from deicing operations; testing of EG and PG degradation using laboratory-scale reactors and then by means of serum bottle tests; operation of an anaerobic fluidized bed reactor (AFBR); and analysis of the energy aspects of anaerobic processes with cost comparisons to traditional aerobic processes.

  13. Going beyond energy intensity to understand the energy metabolism of nations: The case of Argentina

    Microsoft Academic Search

    Marina Recalde; Jesús Ramos-Martin

    2011-01-01

    The link between energy consumption and economic growth has been widely studied in the economic literature. Understanding this relationship is important from both an environmental and a socio-economic point of view, as energy consumption is crucial to economic activity and human environmental impact. This relevance is even higher for developing countries, since energy consumption per unit of output varies through

  14. Metabolic Syndrome

    MedlinePLUS

    ... applies to a condition known as metabolic syndrome. Metabolic Syndrome Is an Early Warning Sign Metabolic syndrome isn' ... 2 diabetes down the road. What Exactly Is Metabolic Syndrome? Metabolic syndrome is a collection of problems that ...

  15. Genome-Based Metabolic Engineering of Mannheimia succiniciproducens for Succinic Acid Production

    Microsoft Academic Search

    Sang Jun Lee; Hyohak Song; Sang Yup Lee

    2006-01-01

    Succinic acid is a four-carbon dicarboxylic acid produced as one of the fermentation products of anaerobic metabolism. Based on the complete genome sequence of a capnophilic succinic acid-producing rumen bacte- rium, Mannheimia succiniciproducens, gene knockout studies were carried out to understand its anaerobic fermentative metabolism and consequently to develop a metabolically engineered strain capable of producing succinic acid without by-product

  16. Signals for the lysosome: a control center for cellular clearance and energy metabolism

    PubMed Central

    Settembre, Carmine; Fraldi, Alessandro; Medina, Diego L.

    2015-01-01

    Preface For a long time lysosomes were considered merely to be cellular “incinerators” involved in the degradation and recycling of cellular waste. However, there is now compelling evidence indicating that lysosomes have a much broader function and that they are involved in fundamental processes such as secretion, plasma membrane repair, signaling and energy metabolism. Furthermore, the essential role of lysosomes in the autophagic pathway puts these organelles at the crossroads of several cellular processes, with significant implications for health and disease. The identification of a master gene, transcription factor EB (TFEB), that regulates lysosomal biogenesis and autophagy, has revealed how the lysosome adapts to environmental cues, such as starvation, and suggests novel therapeutic strategies for modulating lysosomal function in human disease. PMID:23609508

  17. IP3 receptor types 2 and 3 mediate exocrine secretion underlying energy metabolism.

    PubMed

    Futatsugi, Akira; Nakamura, Takeshi; Yamada, Maki K; Ebisui, Etsuko; Nakamura, Kyoko; Uchida, Keiko; Kitaguchi, Tetsuya; Takahashi-Iwanaga, Hiromi; Noda, Tetsuo; Aruga, Jun; Mikoshiba, Katsuhiko

    2005-09-30

    Type 2 and type 3 inositol 1,4,5-trisphosphate receptors (IP3R2 and IP3R3) are intracellular calcium-release channels whose physiological roles are unknown. We show exocrine dysfunction in IP3R2 and IP3R3 double knock-out mice, which caused difficulties in nutrient digestion. Severely impaired calcium signaling in acinar cells of the salivary glands and the pancreas in the double mutants ascribed the secretion deficits to a lack of intracellular calcium release. Despite a normal caloric intake, the double mutants were hypoglycemic and lean. These results reveal IP3R2 and IP3R3 as key molecules in exocrine physiology underlying energy metabolism and animal growth. PMID:16195467

  18. Mild mitochondrial uncoupling in mice affects energy metabolism, redox balance and longevity.

    PubMed

    Caldeira da Silva, Camille C; Cerqueira, Fernanda M; Barbosa, Lívea F; Medeiros, Marisa H G; Kowaltowski, Alicia J

    2008-08-01

    Caloric restriction is the most effective non-genetic intervention to enhance lifespan known to date. A major research interest has been the development of therapeutic strategies capable of promoting the beneficial results of this dietary regimen. In this sense, we propose that compounds that decrease the efficiency of energy conversion, such as mitochondrial uncouplers, can be caloric restriction mimetics. Treatment of mice with low doses of the protonophore 2,4-dinitrophenol promotes enhanced tissue respiratory rates, improved serological glucose, triglyceride and insulin levels, decrease of reactive oxygen species levels and tissue DNA and protein oxidation, as well as reduced body weight. Importantly, 2,4-dinitrophenol-treated animals also presented enhanced longevity. Our results demonstrate that mild mitochondrial uncoupling is a highly effective in vivo antioxidant strategy, and describe the first therapeutic intervention capable of effectively reproducing the physiological, metabolic and lifespan effects of caloric restriction in healthy mammals. PMID:18505478

  19. Anaerobic oxidation of toluene, phenol, and p-cresol by the dissimilatory iron-reducing organism, GS-15

    USGS Publications Warehouse

    Lovley, D.R.; Lonergan, D.J.

    1990-01-01

    The dissimilatory Fe(III) reducer, GS-15, is the first microorganism known to couple the oxidation of aromatic compounds to the reduction of Fe(III) and the first example of a pure culture of any kind known to anaerobically oxidize an aromatic hydrocarbon, toluene. In this study, the metabolism of toluene, phenol, and p-cresol by GS-15 was investigated in more detail. GS-15 grew in an anaerobic medium with toluene as the sole electron donor and Fe(III) oxide as the electron acceptor. Growth coincided with Fe(III) reduction. [ring-14C]toluene was oxidized to 14CO2, and the stoichiometry of 14CO2 production and Fe(III) reduction indicated that GS-15 completely oxidized toluene to carbon dioxide with Fe(III) as the electron acceptor. Magnetite was the primary iron end product during toluene oxidation. Phenol and p-cresol were also completely oxidized to carbon dioxide with Fe(III) as the sole electron acceptor, and GS-15 could obtain energy to support growth by oxidizing either of these compounds as the sole electron donor. p-Hydroxybenzoate was a transitory extracellular intermediate of phenol and p-cresol metabolism but not of toluene metabolism. GS-15 oxidized potential aromatic intermediates in the oxidation of toluene (benzylalcohol and benzaldehyde) and p-cresol (p-hydroxybenzylalcohol and p-hydroxybenzaldehyde). The metabolism described here provides a model for how aromatic hydrocarbons and phenols may be oxidized with the reduction of Fe(III) in contaminated aquifers and petroleum-containing sediments.

  20. Biochemical indices of aerobic and anaerobic capacity in muscle tissues of California elasmobranch fishes differing in typical activity level

    Microsoft Academic Search

    K. A. Dickson; M. O. Gregorio; S. J. Gruber; K. L. Loefler; M. Tran; C. Terrell

    1993-01-01

    Biochemical indices of aerobic and anaerobic metabolic capacity were measured in white myotomal muscle of eight marine elasmobranch fish species representing a broad range of locomotor performance, and in red myotomal muscle and heart of three of those species. The objectives were to determine if metabolic capacities vary with typical fish activity level, to compare the endothermic mako shark with