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1

Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.  

PubMed

Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. PMID:22902601

Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

2012-08-10

2

Carbon monoxide-dependent energy metabolism in anaerobic bacteria and archaea  

Microsoft Academic Search

Despite its toxicity for the majority of living matter on our planet, numerous microorganisms, both aerobic and anaerobic,\\u000a can use carbon monoxide (CO) as a source of carbon and\\/or energy for growth. The capacity to employ carboxidotrophic energy\\u000a metabolism anaerobically is found in phylogenetically diverse members of the Bacteria and the Archaea. The oxidation of CO\\u000a is coupled to numerous

Ellen Oelgeschläger; Michael Rother

2008-01-01

3

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

Microsoft Academic Search

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

Fujio Egami

1974-01-01

4

Role of pyruvate kinase, phosphoenolpyruvate carboxykinase, malic enzyme and lactate dehydrogenase in anaerobic energy metabolism of Tubifex spec  

Microsoft Academic Search

1.During anaerobic exposure ofTubifex, lactate and alanine increase only within the first 24 h, while concentrations of succinate, propionate and also acetate continually increase under prevailing anaerobic conditions. Enzymes involved in anaerobic energy metabolism were isolated, and the effects of various metabolites and inorganic compounds on their catalytic properties studied.2.The specific activities of the cytosolic enzymes LDH, PK, MDH, and

K. H. Hoffmann; T. Mustafa; J. B. Jørgensen

1979-01-01

5

Anaerobic energy metabolism in the oligochaete Lumbriculus variegatus Müller  

Microsoft Academic Search

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.

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

1990-01-01

6

Early anaerobic metabolisms  

PubMed Central

Before the advent of oxygenic photosynthesis, the biosphere was driven by anaerobic metabolisms. We catalogue and quantify the source strengths of the most probable electron donors and electron acceptors that would have been available to fuel early-Earth ecosystems. The most active ecosystems were probably driven by the cycling of H2 and Fe2+ through primary production conducted by anoxygenic phototrophs. Interesting and dynamic ecosystems would have also been driven by the microbial cycling of sulphur and nitrogen species, but their activity levels were probably not so great. Despite the diversity of potential early ecosystems, rates of primary production in the early-Earth anaerobic biosphere were probably well below those rates observed in the marine environment. We shift our attention to the Earth environment at 3.8?Gyr ago, where the earliest marine sediments are preserved. We calculate, consistent with the carbon isotope record and other considerations of the carbon cycle, that marine rates of primary production at this time were probably an order of magnitude (or more) less than today. We conclude that the flux of reduced species to the Earth surface at this time may have been sufficient to drive anaerobic ecosystems of sufficient activity to be consistent with the carbon isotope record. Conversely, an ecosystem based on oxygenic photosynthesis was also possible with complete removal of the oxygen by reaction with reduced species from the mantle.

Canfield, Don E; Rosing, Minik T; Bjerrum, Christian

2006-01-01

7

Energy metabolism among eukaryotic anaerobes in light of Proterozoic ocean chemistry.  

PubMed

Recent years have witnessed major upheavals in views about early eukaryotic evolution. One very significant finding was that mitochondria, including hydrogenosomes and the newly discovered mitosomes, are just as ubiquitous and defining among eukaryotes as the nucleus itself. A second important advance concerns the readjustment, still in progress, about phylogenetic relationships among eukaryotic groups and the roughly six new eukaryotic supergroups that are currently at the focus of much attention. From the standpoint of energy metabolism (the biochemical means through which eukaryotes gain their ATP, thereby enabling any and all evolution of other traits), understanding of mitochondria among eukaryotic anaerobes has improved. The mainstream formulations of endosymbiotic theory did not predict the ubiquity of mitochondria among anaerobic eukaryotes, while an alternative hypothesis that specifically addressed the evolutionary origin of energy metabolism among eukaryotic anaerobes did. Those developments in biology have been paralleled by a similar upheaval in the Earth sciences regarding views about the prevalence of oxygen in the oceans during the Proterozoic (the time from ca 2.5 to 0.6 Ga ago). The new model of Proterozoic ocean chemistry indicates that the oceans were anoxic and sulphidic during most of the Proterozoic. Its proponents suggest the underlying geochemical mechanism to entail the weathering of continental sulphides by atmospheric oxygen to sulphate, which was carried into the oceans as sulphate, fueling marine sulphate reducers (anaerobic, hydrogen sulphide-producing prokaryotes) on a global scale. Taken together, these two mutually compatible developments in biology and geology underscore the evolutionary significance of oxygen-independent ATP-generating pathways in mitochondria, including those of various metazoan groups, as a watermark of the environments within which eukaryotes arose and diversified into their major lineages. PMID:18468979

Mentel, Marek; Martin, William

2008-08-27

8

Endogenous Metabolism of Anaerobic Bacteria.  

National Technical Information Service (NTIS)

Further investigations of the endogenous metabolism and survival of non-spore-forming anaerobic bacteria Zymomonas anaerobia and Peptococcus prevotii under conditions of starvation are reported. To permit studies with cells whose growth has been halted by...

E. A. Dawes P. J. Large

1968-01-01

9

Use of carbon and energy balances in the study of the anaerobic metabolism of Enterobacter aerogenes at variable starting glucose concentrations  

Microsoft Academic Search

The anaerobic metabolism of Enterobacter aerogenes was studied in batch culture at increasing initial glucose levels (9.0So -1). The ultimate concentrations of fermentation products were utilized to check a metabolic flux analysis based on simple carbon mass and energy balances that promise to be suitable for the study of different fermentation processes, either under aerobic or anaerobic conditions. The stoichiometric

A. Converti; P. Perego

2002-01-01

10

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

PubMed

Due to current technical difficulties and changing cellular conditions, the measurement of anaerobic and recovery energy expenditure remains elusive. During rest and low-intensity steady-state exercise, indirect calorimetric measurements successfully 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 O2 deficit plus exercise O2 uptake measurement ignores energy expenditure during recovery, and an exercise O2 uptake plus EPOC measurement misrepresents anaerobic energy expenditure. An alternative solution has not yet been proposed. Anaerobic glycolysis and mitochondrial respiration are construed here as a symbiotic union of metabolic pathways, each contributing independently to energy expenditure and heat production. Care must be taken when using O2 uptake alone to quantify energy expenditure because various high-intensity exercise models reveal that O2 uptake can lag behind estimated energy demands or exceed them. The independent bioenergetics behind anaerobic glycolysis and mitochondrial respiration can acknowledge these discrepancies. Anaerobic glycolysis is an additive component to an exercise O2 uptake measurement. Moreover, it is the assumptions behind steady-state O2 uptake that do not permit proper interpretation of energy expenditure during EPOC; 1 l O2 not = 20.9 kJ. Using both the O2 deficit and a modified EPOC for interpretation, rather than one or the other, leads to a better method of quantifying energy expenditure for higher intensity exercise and recovery. PMID:9535579

Scott, C B

1998-02-01

11

The anammoxosome organelle is crucial for the energy metabolism of anaerobic ammonium oxidizing bacteria.  

PubMed

Anammox bacteria convert ammonium and nitrite to dinitrogen gas under anaerobic conditions to obtain their energy for growth. The anammox reaction was deemed impossible until its discovery in the early 1990s. Now, anammox bacteria are recognized as major players in the global nitrogen cycle and estimated to be responsible for up to 50% of the nitrogen in the air that we breathe. In addition, anammox bacteria are extremely valuable for wastewater treatment where they are applied for the removal of ammonium. Besides their importance in industry and the environment, anammox bacteria defy some basic biological concepts. Whereas most other bacteria have only one cell compartment, the cytoplasm, anammox bacteria have three independent cell compartments bounded by bilayer membranes, from out- to inside; the paryphoplasm, riboplasm and anammoxosome. The anammoxosome is the largest compartment of the anammox cell and is proposed to be dedicated to energy conservation. As such it would be analogous to the mitochondria of eukaryotes. This review will discuss the anammox cell plan in detail, with the main focus on the anammoxosome. The identity of the anammoxosome as a prokaryotic organelle and the importance of this organelle for anammox bacteria are discussed as well as challenges these bacteria face by having three independent cell compartments. PMID:23615199

van Teeseling, Muriel C F; Neumann, Sarah; van Niftrik, Laura

2013-04-18

12

Modulation of Anaerobic Energy Metabolism of Bacillus subtilis by arfM (ywiD)  

Microsoft Academic Search

Bacillus subtilis grows under anaerobic conditions utilizing nitrate ammonification and various fermentative processes. The two-component regulatory system ResDE and the redox regulator Fnr are the currently known parts of the regulatory system for anaerobic adaptation. Mutation of the open reading frame ywiD located upstream of the respiratory nitrate reductase operon narGHJI resulted in elimination of the contribution of nitrite dissimilation

MARCO MARINO; HUGO CRUZ RAMOS; TAMARA HOFFMANN; PHILIPPE GLASER; DIETER JAHN

2001-01-01

13

Aerobic and Anaerobic Starvation Metabolism in Methanotrophic Bacteria  

PubMed Central

The capacity for anaerobic metabolism of endogenous and selected exogenous substrates in carbon- and energy-starved methanotrophic bacteria was examined. The methanotrophic isolate strain WP 12 survived extended starvation under anoxic conditions while metabolizing 10-fold less endogenous substrate than did parallel cultures starved under oxic conditions. During aerobic starvation, the cell biomass decreased by 25% and protein and lipids were the preferred endogenous substrates. Aerobic protein degradation (24% of total protein) took place almost exclusively during the initial 24 h of starvation. Metabolized carbon was recovered mainly as CO(inf2) during aerobic starvation. In contrast, cell biomass decreased by only 2.4% during anaerobic starvation, and metabolized carbon was recovered mainly as organic solutes in the starvation medium. During anaerobic starvation, only the concentration of intracellular low-molecular-weight compounds decreased, whereas no significant changes were measured for cellular protein, lipids, polysaccharides, and nucleic acids. Strain WP 12 was also capable of a limited anaerobic glucose metabolism in the absence of added electron acceptors. Small amounts of CO(inf2) and organic acids, including acetate, were produced from exogenous glucose under anoxic conditions. Addition of potential anaerobic electron acceptors (fumarate, nitrate, nitrite, or sulfate) to starved cultures of the methanotrophs Methylobacter albus BG8, Methylosinus trichosporium OB3b, and strain WP 12 did not stimulate anaerobic survival. However, anaerobic starvation of these bacteria generally resulted in better survival than did aerobic starvation. The results suggest that methanotrophic bacteria can enter a state of anaerobic dormancy accompanied by a severe attenuation of endogenous metabolism. In this state, maintenance requirements are presumably provided for by fermentation of certain endogenous substrates. In addition, low-level catabolism of exogenous substrates may support long-term anaerobic survival of some methanotrophic bacteria.

Roslev, P.; King, G. M.

1995-01-01

14

Effects of cadmium on anaerobic energy metabolism and mRNA expression during air exposure and recovery of an intertidal mollusk Crassostrea virginica.  

PubMed

Marine organisms are exposed to periodical oxygen deficiency and pollution stress in estuarine and coastal zones which may strongly affect their performance and survival. We studied the combined effects of exposure to a common pollutant, cadmium (Cd), and intermittent anoxia on anaerobic metabolism, energy status and mRNA expression of 13 genes involved in and/or controlled by the hypoxia inducible factor-1 (HIF-1) pathway in hepatopancreas of an intertidal bivalve, the eastern oyster Crassostrea virginica. In control oysters, prolonged anoxia resulted in a selective suppression of nitric oxide synthase (NOS) and upregulation of cytochrome c oxidase subunit IV (COX4) while the levels of other transcripts remained unchanged. During post-anoxic recovery, mRNA expression of hypoxia inducible factor-1alpha (HIF-1alpha) was elevated, phosphoenolpyruvate carboxykinase (PEPCK), NOS and LON protease suppressed, and mRNA expression of other studied genes not changed. Notably, most of the key glycolytic genes that are stimulated by HIF-1 in mammals, either remained unchanged or were downregulated in anoxic oysters suggesting a different mechanism of molecular response to oxygen deficiency. Patterns of transcriptional response during anoxia and reoxygenation were significantly altered by Cd exposure in a gene-specific manner. Anaerobic metabolism (indicated by accumulation of l-alanine, succinate and acetate during anoxia) was also suppressed in Cd-exposed oysters. In control oysters, ATP turnover rate (M(ATP)) during anoxia was mostly sustained by anaerobic glycolysis with negligible contributions from ATP and PLA breakdown. In contrast, in Cd-exposed oysters ATP breakdown contributed significantly to anaerobic M(ATP). Thus, while control oysters could efficiently defend the ATP levels and tissue energy status during prolonged anoxia, Cd-exposed oysters experienced a disturbance in tissue energy balance indicated by the depletion of ATP, a rapid decline in adenylate energy charge and increase in ADP/ATP ratios. This energy deficiency combined with suppression of anaerobic metabolism may strongly affect performance and survival of oysters in polluted estuaries where metal pollution may co-occur with "dead zones". PMID:20538354

Ivanina, Anna V; Sokolov, Eugene P; Sokolova, Inna M

2010-05-24

15

Metabolic reprogramming under microaerobic and anaerobic conditions in bacteria.  

PubMed

Oxygen has a great impact on the metabolism and physiology of microorganisms. It serves as the most efficient terminal electron acceptor to drive the energy conservation process of cellular respiration and is required in many biosynthetic reactions. Bacteria encounter oxygen fluctuation and limitation during their growth in both natural ecological niches and in laboratory vessels. In response to oxygen limitation, facultative bacteria undergo substantial metabolic reprogramming to switch from the aerobic respiration to either anaerobic respiration, fermentation, or photosynthesis. Two key factors determine the metabolic pathways bacteria adopt under oxygen deprived microaerobic and anaerobic conditions: maximal energy conservation and redox homeostasis. In this chapter, we first describe how the fulfillment of these two key factors governs the metabolic reprogramming of facultative bacteria and how the process is tightly controlled by several global regulatory factors: FNR, ArcBA, as well as NarL and NarP. We then utilizes fermentation of glycerol, a large surplus byproduct of biodiesel industry, as an example to illustrate how environment, process, and strain based approaches can be exploited to manipulate and engineer the anaerobic metabolic pathways so that desirable fermentation products can be achieved with optimal yield. PMID:23080250

Shan, Yue; Lai, Yong; Yan, Aixin

2012-01-01

16

Anaerobic metabolic processes in the deep terrestrial subsurface  

Microsoft Academic Search

Anaerobic microorganisms were enumerated and metabolic activities measured in deep Coastal Plain sediments sampled from three water?bearing formations at depths down to 300 m. Aseptically obtained sediment cores harbored the potential for anaerobic biodegradation of various substrates in almost all samples. Although the sediments were not predominantly anaerobic, viable methanogens and sulfate?reducing bacteria (SRB) were present almost throughout the depth

Ralph E. Jones; Ralph E. Beeman; Joseph M. Suflita

1989-01-01

17

Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes  

Microsoft Academic Search

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

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

2003-01-01

18

Anaerobic Metabolism and Bioremediation of Explosives-Contaminated Soil  

NASA Astrophysics Data System (ADS)

Nitroaromatic compounds pollute soil, water, and food via use of pesticides, plastics, pharmaceuticals, landfill dumping of industrial wastes, and the military use of explosives. Biotransformation of trinitrotoluene and other nitroaromatics by aerobic bacteria in the laboratory has been frequently reported, but the anaerobic bacterial metabolism of nitroaromatics has not been studied as extensively perhaps due to the difficulty in working with anaerobic cultures and the slow growth of anaerobes. Sulfate-reducing and methanogenic bacteria can metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment.

Boopathy, Raj

19

Unifying concepts in anaerobic respiration: insights from dissimilatory sulfur metabolism.  

PubMed

Behind the versatile nature of prokaryotic energy metabolism is a set of redox proteins having a highly modular character. It has become increasingly recognized that a limited number of redox modules or building blocks appear grouped in different arrangements, giving rise to different proteins and functionalities. This modularity most likely reveals a common and ancient origin for these redox modules, and is obviously reflected in similar energy conservation mechanisms. The dissimilation of sulfur compounds was probably one of the earliest biological strategies used by primitive organisms to obtain energy. Here, we review some of the redox proteins involved in dissimilatory sulfur metabolism, focusing on sulfate reducing organisms, and highlight links between these proteins and others involved in different processes of anaerobic respiration. Noteworthy are links to the complex iron-sulfur molybdoenzyme family, and heterodisulfide reductases of methanogenic archaea. We discuss how chemiosmotic and electron bifurcation/confurcation may be involved in energy conservation during sulfate reduction, and how introduction of an additional module, multiheme cytochromes c, opens an alternative bioenergetic strategy that seems to increase metabolic versatility. Finally, we highlight new families of heterodisulfide reductase-related proteins from non-methanogenic organisms, which indicate a widespread distribution for these protein modules and may indicate a more general involvement of thiol/disulfide conversions in energy metabolism. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. PMID:22982583

Grein, Fabian; Ramos, Ana Raquel; Venceslau, Sofia S; Pereira, Inês A C

2012-09-11

20

Contribution of anaerobic energy expenditure to whole body thermogenesis  

PubMed Central

Heat production serves as the standard measurement for the determination of energy expenditure and efficiency in animals. Estimations of metabolic heat production have traditionally focused on gas exchange (oxygen uptake and carbon dioxide production) although direct heat measurements may include an anaerobic component particularly when carbohydrate is oxidized. Stoichiometric interpretations of the ratio of carbon dioxide production to oxygen uptake suggest that both anaerobic and aerobic heat production and, by inference, all energy expenditure – can be accounted for with a measurement of oxygen uptake as 21.1 kJ per liter of oxygen. This manuscript incorporates contemporary bioenergetic interpretations of anaerobic and aerobic ATP turnover to promote the independence of these disparate types of metabolic energy transfer: each has different reactants and products, uses dissimilar enzymes, involves different types of biochemical reactions, takes place in separate cellular compartments, exploits different types of gradients and ultimately each operates with distinct efficiency. The 21.1 kJ per liter of oxygen for carbohydrate oxidation includes a small anaerobic heat component as part of anaerobic energy transfer. Faster rates of ATP turnover that exceed mitochondrial respiration and that are supported by rapid glycolytic phosphorylation with lactate production result in heat production that is independent of oxygen uptake. Simultaneous direct and indirect calorimetry has revealed that this anaerobic heat does not disappear when lactate is later oxidized and so oxygen uptake does not adequately measure anaerobic efficiency or energy expenditure (as was suggested by the "oxygen debt" hypothesis). An estimate of anaerobic energy transfer supplements the measurement of oxygen uptake and may improve the interpretation of whole-body energy expenditure.

Scott, Christopher B

2005-01-01

21

The tangled past of eukaryotic enzymes involved in anaerobic metabolism  

PubMed Central

There is little doubt that genes can spread across unrelated prokaryotes, eukaryotes and even between these domains. It is expected that organisms inhabiting a common niche may exchange their genes even more often due to their physical proximity and similar demands. One such niche is anaerobic or microaerophilic environments in some sediments and intestines of animals. Indeed, enzymes advantageous for metabolism in these environments often exhibit an evolutionary history incoherent with the history of their hosts indicating potential transfers. The evolutionary paths of some very basic enzymes for energy metabolism of anaerobic eukaryotes (pyruvate formate lyase, pyruvate:ferredoxin oxidoreductase, [FeFe]hydrogenase and arginine deiminase) seems to be particularly intriguing and although their histories are not identical they share several unexpected features in common. Every enzyme mentioned above is present in groups of eukaryotes that are unrelated to each other. Although the enzyme phylogenies are not always robustly supported, they always suggest that the eukaryotic homologues form one or two clades, in which the relationships are not congruent with the eukaryotic phylogeny. Finally, these eukaryotic enzymes are never specifically related to homologues from ?-proteobacteria, ancestors of mitochondria. The most plausible explanation for evolution of this pattern expects one or two interdomain transfers to one or two eukaryotes from prokaryotes, who were not the mitochondrial endosymbiont. Once the genes were introduced into the eukaryotic domain they have spread to other eukaryotic groups exclusively via eukaryote-to-eukaryote transfers. Currently, eukaryote-to-eukaryote gene transfers have been regarded as less common than prokaryote-to-eukaryote transfers. The fact that eukaryotes accepted genes for these enzymes solely from other eukaryotes and not prokaryotes present in the same environment is surprising.

Stairs, Courtney W; Roger, Andrew J

2011-01-01

22

Energy metabolism in nuclear reprogramming.  

PubMed

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

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

2011-12-01

23

Redesigning Escherichia coli Metabolism for Anaerobic Production of Isobutanol?†  

PubMed Central

Fermentation enables the production of reduced metabolites, such as the biofuels ethanol and butanol, from fermentable sugars. This work demonstrates a general approach for designing and constructing a production host that uses a heterologous pathway as an obligately fermentative pathway to produce reduced metabolites, specifically, the biofuel isobutanol. Elementary mode analysis was applied to design an Escherichia coli strain optimized for isobutanol production under strictly anaerobic conditions. The central metabolism of E. coli was decomposed into 38,219 functional, unique, and elementary modes (EMs). The model predictions revealed that during anaerobic growth E. coli cannot produce isobutanol as the sole fermentative product. By deleting 7 chromosomal genes, the total 38,219 EMs were constrained to 12 EMs, 6 of which can produce high yields of isobutanol in a range from 0.29 to 0.41 g isobutanol/g glucose under anaerobic conditions. The remaining 6 EMs rely primarily on the pyruvate dehydrogenase enzyme complex (PDHC) and are typically inhibited under anaerobic conditions. The redesigned E. coli strain was constrained to employ the anaerobic isobutanol pathways through deletion of 7 chromosomal genes, addition of 2 heterologous genes, and overexpression of 5 genes. Here we present the design, construction, and characterization of an isobutanol-producing E. coli strain to illustrate the approach. The model predictions are evaluated in relation to experimental data and strategies proposed to improve anaerobic isobutanol production. We also show that the endogenous alcohol/aldehyde dehydrogenase AdhE is the key enzyme responsible for the production of isobutanol and ethanol under anaerobic conditions. The glycolytic flux can be controlled to regulate the ratio of isobutanol to ethanol production.

Trinh, Cong T.; Li, Johnny; Blanch, Harvey W.; Clark, Douglas S.

2011-01-01

24

Anaerobic Metabolism and Bioremediation of Explosives-Contaminated Soil  

Microsoft Academic Search

\\u000a Nitroaromatic compounds pollute soil, water, and food via use of pesticides, plastics, pharmaceuticals, landfill dumping of\\u000a industrial wastes, and the military use of explosives. Biotransformation of trinitrotoluene and other nitroaromatics by aerobic\\u000a bacteria in the laboratory has been frequently reported, but the anaerobic bacterial metabolism of nitroaromatics has not\\u000a been studied as extensively perhaps due to the difficulty in working

Raj Boopathy

2009-01-01

25

Metabolism of Dichloromethane by the Strict Anaerobe Dehalobacterium formicoaceticum  

Microsoft Academic Search

The metabolism of dichloromethane by Dehalobacterium formicoaceticum in cell suspensions and crude cell extracts was investigated. The organism is a strictly anaerobic gram-positive bacterium that utilizes exclusively dichloromethane as a growth substrate and ferments this compound to formate and acetate in a molar ratio of 2:1. When (13C)dichloromethane was degraded by cell suspensions, formate, the methyl group of acetate, and

ANDREAS MAGLI; MICHAEL MESSMER; THOMAS LEISINGER

1998-01-01

26

Intermediary Metabolism in Protists: a Sequence-based View of Facultative Anaerobic Metabolism in Evolutionarily Diverse Eukaryotes  

PubMed Central

Protists account for the bulk of eukaryotic diversity. Through studies of gene and especially genome sequences the molecular basis for this diversity can be determined. Evident from genome sequencing are examples of versatile metabolism that go far beyond the canonical pathways described for eukaryotes in textbooks. In the last 2–3 years, genome sequencing and transcript profiling has unveiled several examples of heterotrophic and phototrophic protists that are unexpectedly well-equipped for ATP production using a facultative anaerobic metabolism, including some protists that can (Chlamydomonas reinhardtii) or are predicted (Naegleria gruberi, Acanthamoeba castellanii, Amoebidium parasiticum) to produce H2 in their metabolism. It is possible that some enzymes of anaerobic metabolism were acquired and distributed among eukaryotes by lateral transfer, but it is also likely that the common ancestor of eukaryotes already had far more metabolic versatility than was widely thought a few years ago. The discussion of core energy metabolism in unicellular eukaryotes is the subject of this review. Since genomic sequencing has so far only touched the surface of protist diversity, it is anticipated that sequences of additional protists may reveal an even wider range of metabolic capabilities, while simultaneously enriching our understanding of the early evolution of eukaryotes.

Ginger, Michael L.; Fritz-Laylin, Lillian K.; Fulton, Chandler; Cande, W. Zacheus; Dawson, Scott C.

2011-01-01

27

Carbohydrate oxidation coupled to Fe(III) reduction, a novel form of anaerobic metabolism  

Microsoft Academic Search

An isolate, designated GC-29, that could incompletely oxidize glucose to acetate and carbon dioxide with Fe(III) serving as the electron acceptor was recovered from freshwater sediments of the Potomac River, Maryland. This metabolism yielded energy to support cell growth. Strain GC-29 is a facultatively anaerobic, Gram-negative motile rod which, in addition to glucose, also used sucrose, lactate, pyruvate, yeast extract,

John D. Coates; Terry Councell; Debra J. Ellis; Derek R. Lovley

1998-01-01

28

Involvement of mitochondria in the assimilatory metabolism of anaerobic Saccharomyces cerevisiae cultures.  

PubMed

The possible physiological role of mitochondria in anaerobically grown Saccharomyces cerevisiae was investigated via enzyme localization and inhibitor studies. Almost all of the activity of citrate synthase (EC 4.1.3.7) was recovered in the mitochondrial fraction after differential centrifugation of spheroplast lysates. The enzyme exhibited a high degree of latency which was demonstrated by sonication of the mitochondrial fractions. Since citrate synthase is an important enzyme in anabolic reactions, a consequence of this localization is the requirement for transport of metabolites across the mitochondrial membranes. Such transport is likely to require energy which, as a result of anaerobiosis, cannot be supplied by respiration. It was therefore investigated whether ATP translocation into the mitochondria by an ADP/ATP translocase might be involved in anaerobic mitochondrial energy metabolism. It was shown that addition of the ADP/ATP translocase inhibitor bongkrekic acid to anaerobic cultures indeed inhibited growth, although only partially. It is concluded that mitochondria of S. cerevisiae fulfil a vital role in anaerobic sugar metabolism. PMID:7812444

Visser, W; van der Baan, A A; Batenburg-van der Vegte, W; Scheffers, W A; Krämer, R; van Dijken, J P

1994-11-01

29

Metabolism of Dichloromethane by the Strict Anaerobe Dehalobacterium formicoaceticum  

PubMed Central

The metabolism of dichloromethane by Dehalobacterium formicoaceticum in cell suspensions and crude cell extracts was investigated. The organism is a strictly anaerobic gram-positive bacterium that utilizes exclusively dichloromethane as a growth substrate and ferments this compound to formate and acetate in a molar ratio of 2:1. When [13C]dichloromethane was degraded by cell suspensions, formate, the methyl group of acetate, and minor amounts of methanol were labeled, but there was no nuclear magnetic resonance signal corresponding to the carboxyl group of acetate. This finding and previously established carbon and electron balances suggested that dichloromethane was converted to methylene tetrahydrofolate, of which two-thirds was oxidized to formate while one-third gave rise to acetate by incorporation of CO2 from the medium in the acetyl coenzyme A synthase reaction. When crude desalted extracts were incubated in the presence of dichloromethane, tetrahydrofolate, ATP, methyl viologen, and molecular hydrogen, dichloromethane and tetrahydrofolate were consumed, with the concomitant formation of stoichiometric amounts of methylene tetrahydrofolate. The in vitro transfer of the methylene group of dichloromethane onto tetrahydrofolate required substoichiometric amounts of ATP. The reaction was inhibited in a light-reversible fashion by 20 ?M propyl iodide, thus suggesting involvement of a Co(I) corrinoid in the anoxic dehalogenation of dichloromethane. D. formicoaceticum exhibited normal growth with 0.8 mM sodium in the medium, and crude extracts contained ATPase activity that was partially inhibited by N,N?-dicyclohexylcarbodiimide and azide. During growth with dichloromethane, the organism thus may conserve energy not only by substrate-level phosphorylation but also by a chemiosmotic mechanism involving a sodium-independent F0F1-type ATP synthase.

Magli, Andreas; Messmer, Michael; Leisinger, Thomas

1998-01-01

30

Anaerobic performance and metabolism in boys and male adolescents  

Microsoft Academic Search

Short-term maximum intensity performance, absolute and related to body mass, is lower in children than adolescents. The underlying\\u000a mechanisms are not clear. We analysed Wingate Anaerobic Test (WAnT) performance and metabolism in ten boys (mean (SD); age\\u000a 11.8 (0.5) years, height 1.51 (0.05) m, body mass 36.9 (2.5) kg, muscle mass 13.0 (1.0) kg) and 10 adolescents (16.3 (0.7)\\u000a years,

Ralph Beneke; Matthias Hütler; Renate M. Leithäuser

2007-01-01

31

Anaerobiosis and acid-base status in marine invertebrates: a theoretical analysis of proton generation by anaerobic metabolism  

Microsoft Academic Search

In animals, various organic acids are accumulated during hypoxia or anoxia as products of anaerobic energy metabolism. The diversity of such acids is largest in marine invertebrates where succinate, propionate, acetate, lactate, alanine, octopine, strombine, and alanopine, are produced mainly from glycogen and aspartate. The effect of these substances on the acid-base status was assessed by a theoretical analysis of

H. O. Pörtner; N. Heisler; M. K. Grieshaber

1984-01-01

32

Involvement of coenzyme A thioesters in anaerobic metabolism of 4-hydroxybenzoate by Rhodopseudomonas palustris  

SciTech Connect

The initial steps of anaerobic 4-hydroxybenzoate degradation were studied in whole cells and cell extracts of the photosynthetic bacterium Rhodopseudomonas palustris. Illuminated suspensions of cells that had been grown anaerobically on 4-hydroxybenzoate and were assayed under anaerobic conditions took up (U-14C)4-hydroxybenzoate at a rate of 0.6 nmol min-1 mg of protein-1. Uptake occurred with high affinity (apparent Km = 0.3 microM), was energy dependent, and was insensitive to external pH in the range of 6.5 to 8.2 Very little free 4-hydroxybenzoate was found associated with cells, but a range of intracellular products was formed after 20-s incubations of whole cells with labeled substrate. When anaerobic pulse-chase experiments were carried out with cells incubated on ice or in darkness, 4-hydroxybenzoyl coenzyme A (4-hydroxybenzoyl-CoA) was formed early and disappeared immediately after addition of excess unlabeled substrate, as would be expected of an early intermediate in 4-hydroxybenzoate metabolism. A 4-hydroxybenzoate-CoA ligase activity with an average specific activity of 0.7 nmol min-1 mg of protein-1 was measured in the soluble protein fraction of cells grown anaerobically on 4-hydroxybenzoate. 4-Hydroxybenzoyl-CoA was the sole product formed from labeled 4-hydroxybenzoate in the ligase reaction mixture. 4-Hydroxybenzoate uptake and ligase activities were present in cells grown anaerobically with benzoate, 4-hydroxybenzoate, and 4-aminobenzoate and were not detected in succinate-grown cells.

Merkel, S.M.; Eberhard, A.E.; Gibson, J.; Harwood, C.S.

1989-01-01

33

One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production  

SciTech Connect

This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. (CBS)

Zeikus, J.G.; Jain, M.K.

1992-01-01

34

Environmental factors affecting indole metabolism under anaerobic conditions.  

PubMed Central

The influence of physiological and environmental factors on the accumulation of oxindole during anaerobic indole metabolism was investigated by high-performance liquid chromatography. Under methanogenic conditions, indole was temporarily converted to oxindole in stoichiometric amounts in media inoculated with three freshwater sediments and an organic soil. In media inoculated with methanogenic sewage sludge, the modest amounts of oxindole detected at 35 degrees C reached higher concentrations and persisted longer when the incubation temperature was decreased from 35 to 15 degrees C. Also, decreasing the concentration of sewage sludge used as an inoculum from 50 to 1% caused an increase in the accumulation of oxindole from 10 to 75% of the indole added. Under denitrifying conditions, regardless of the concentration or source of the inoculum, oxindole appeared in trace amounts but did not accumulate during indole metabolism. In addition, denitrifying consortia which previously metabolized indole degraded oxindole with no lag period. Our data suggest that oxindole accumulation under methanogenic, but not under denitrifying conditions is caused by differences between relative rates of oxindole production and destruction.

Madsen, E L; Francis, A J; Bollag, J M

1988-01-01

35

Carbohydrate oxidation coupled to Fe(III) reduction, a novel form of anaerobic metabolism.  

PubMed

An isolate, designated GC-29, that could incompletely oxidize glucose to acetate and carbon dioxide with Fe(III) serving as the electron acceptor was recovered from freshwater sediments of the Potomac River, Maryland. This metabolism yielded energy to support cell growth. Strain GC-29 is a facultatively anaerobic, gram-negative motile rod which, in addition to glucose, also used sucrose, lactate, pyruvate, yeast extract, casamino acids or H2 as alternative electron donors for Fe(III) reduction. Stain GC-29 could reduce NO3(-), Mn(IV), U(VI), fumarate, malate, S2O3(2-), and colloidal S0 as well as the humics analog, 2,6-anthraquinone disulfonate. Analysis of the almost complete 16S rRNA sequence indicated that strain GC-29 belongs in the Shewanella genus in the epsilon subdivision of the Proteobacteria. The name Shewanella saccharophilia is proposed. Shewanella saccharophilia differs from previously described fermentative microorganisms that metabolize glucose with the reduction of Fe(III) because it transfers significantly more electron equivalents to Fe(III); acetate and carbon dioxide are the only products of glucose metabolism; energy is conserved from Fe(III) reduction; and glucose is not metabolized in the absence of Fe(III). The metabolism of organisms like S. saccharophilia may account for the fact that glucose is metabolized primarily to acetate and carbon dioxide in a variety of sediments in which Fe(III) reduction is the terminal electron accepting process. PMID:16887653

Coates, J D; Councell, T; Ellis, D J; Lovley, D R

1998-12-01

36

Anaerobic biodegradation of vegetable oil and its metabolic intermediates in oil-enriched freshwater sediments  

Microsoft Academic Search

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 fatty acids (LCFAs) that are produced as intermediates during metabolism of vegetable-oil triglycerides. The anaerobic biodegradation of canola oil and

Zhengkai Li; Brian A. Wrenn; Albert D. Venosa

2005-01-01

37

Metabolic control analysis of anaerobic glycolysis in human hibernating myocardium replaces traditional concepts of flux control  

Microsoft Academic Search

Myocardial hibernation represents an adaptation to sustained ischemia to maintain tissue vitality during severe supply–demand imbalance which is characterized by an increased glucose uptake. To elucidate this adaptive protective mechanism, the regulation of anaerobic glycolysis was investigated using human biopsies. In hibernating myocardium showing an increase in anaerobic glycolytic flux metabolizing exogenous glucose, the adjustment of flux through this pathway

Achim M. Vogt; Holger Nef; Jutta Schaper; Mark Poolman; David A. Fell; Wolfgang Kübler; Albrecht Elsässer

2002-01-01

38

One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production.  

National Technical Information Service (NTIS)

The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the produ...

J. G. Zeikus M. Jain

1993-01-01

39

Metabolic Interactions Between Methanogenic Consortia and Anaerobic Respiring Bacteria  

Microsoft Academic Search

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

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

2003-01-01

40

Energetics of end product excretion in anaerobic bacteria and the metabolism of fatty acids by Syntrophomonas wolfei  

SciTech Connect

The study of anaerobic hydrogen-producing syntrophic bacteria is important for several reasons. These bacteria degrade fatty acids which are important intermediates in anaerobic degradation and methanogenesis. The rate and extent of anaerobic degradation of complex polymeric materials often depends on the activity of these organisms. The production of H{sub 2} during anaerobic fatty acid degradation is energetically favorable only when H{sub 2} is maintained at a low level by another bacterium such as a H{sub 2}- using methanogen. Thus, the fatty acid-degrading syntrophic associations serve as excellent models to study the biochemical aspects of mutualism. The fatty acid-degrading syntrophic bacteria are very slow growers since little free energy is released during fatty acid degradation. These bacteria must have very efficient energy conservation systems which are not understood at this time. Further study of these organisms will provide useful information on bioenergetics of living systems. We have chosen to study the metabolism and energetics of the anaerobic, syntrophic, fatty acid degrader, Syntrophomonas wolfei. This organism is the best characterized syntrophic bacterium and serves as an appropriate model organism.

McInerney, M.J.

1986-01-01

41

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

Microsoft Academic Search

Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paeniba- cillus, 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

Ashutosh Gupta; Abhishek Murarka; Paul Campbell; Ramon Gonzalez

2009-01-01

42

Anaerobic metabolism in the leech ( Hirudo medicinalis L.): direct and indirect calorimetry during severe hypoxia  

Microsoft Academic Search

Anaerobic metabolism in the limnic annelid Hirudo medicinalis L. was investigated by direct and indirect calorimetry. During long-term severe hypoxia, the rate of heat dissipation was reduced up to 13% of the aerobic rate. At the same time, the rate of ATP turnover was reduced to about 30% of the aerobic rate, indicating that metabolic depression is an important mechanism

H. Schmidt; A. Wichmann; I. Lamprecht; I. Zerbst-Boroffka

1996-01-01

43

One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production  

Microsoft Academic Search

The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron

J. G. Zeikus; M. Jain

1993-01-01

44

Interpreting energy expenditure for anaerobic exercise and recovery: an anaerobic hypothesis.  

PubMed

Energy expenditure during and after exercise is composed of aerobic and anaerobic bioenergetics and the energy demands of aerobic recovery. Current attempts to measure energy expenditure include an exercise oxygen uptake + oxygen debt (EPOC) measurement or, an oxygen deficit + exercise oxygen uptake measurement. This investigation illustrates how oxygen debt and oxygen deficit interpretation can effect a total energy expenditure measurement. It was hypothesized that the total energy expenditure for several intermittent bouts of exercise and recovery would be greater than for one bout of continuous exercise and recovery when equivalent work was compared. Exercise was performed under low-intensity and high-intensity conditions. Both oxygen debt and oxygen deficit methodology resulted in similar energy expenditure measurements for both intermittent and continuous exercise. This implies little to no recovery energy demand or considerable methodology errors. Differences in total energy expenditure were found when the oxygen deficit and parts of the oxygen debt (EPOC) were considered separate and independent (p < 0.05). These differences can be accounted for when the data are interpreted utilizing thermodynamic (2nd law) and engineering (in-series efficiency) concepts rather than the heat equivalent of carbohydrate oxidation (20.9 kJ equals one liter of O2). It is suggested that while oxygen uptake provides an excellent representation of aerobic metabolism during exercise and recovery, oxygen uptake may be an inadequate measure of the energetics of lactate production (fermentation). In application, energy expenditure differences appear realistic only for high-intensity, intermittent exercise rather than lower intensity exercise. PMID:9190121

Scott, C B

1997-03-01

45

Transcriptional regulation of metabolic pathways, alternative respiration and enterotoxin genes in anaerobic growth of Bacillus cereus ATCC 14579  

Microsoft Academic Search

Aims: To assess genes specifically activated during anaerobic growth that are involved in metabolism and pathogenesis of the foodborne pathogen Bacillus cereus. Methods and Results: Growth under anaerobic conditions in Brain Heart Infusion (BHI) broth revealed a reduced growth rate and lower yield as compared to growth under aerobic conditions. Subsequently, comparative transcriptome analysis showed specific genes induced under anaerobic

Voort van der M; T. Abee

2009-01-01

46

Anaerobic metabolism at thermal extremes: a metabolomic test of the oxygen limitation hypothesis in an aquatic insect.  

PubMed

Thermal limits in ectotherms may arise through a mismatch between supply and demand of oxygen. At higher temperatures, the ability of their cardiac and ventilatory activities to supply oxygen becomes insufficient to meet their elevated oxygen demand. Consequently, higher levels of oxygen in the environment are predicted to enhance tolerance of heat, whereas reductions in oxygen are expected to reduce thermal limits. Here, we extend previous research on thermal limits and oxygen limitation in aquatic insect larvae and directly test the hypothesis of increased anaerobic metabolism and lower energy status at thermal extremes. We quantified metabolite profiles in stonefly nymphs under varying temperatures and oxygen levels. Under normoxia, the concept of oxygen limitation applies to the insects studied. Shifts in the metabolome of heat-stressed stonefly nymphs clearly indicate the onset of anaerobic metabolism (e.g., accumulation of lactate, acetate, and alanine), a perturbation of the tricarboxylic acid cycle (e.g., accumulation of succinate and malate), and a decrease in energy status (e.g., ATP), with corresponding decreases in their ability to survive heat stress. These shifts were more pronounced under hypoxic conditions, and negated by hyperoxia, which also improved heat tolerance. Perturbations of metabolic pathways in response to either heat stress or hypoxia were found to be somewhat similar but not identical. Under hypoxia, energy status was greatly compromised at thermal extremes, but energy shortage and anaerobic metabolism could not be conclusively identified as the sole cause underlying thermal limits under hyperoxia. Metabolomics proved useful for suggesting a range of possible mechanisms to explore in future investigations, such as the involvement of leaking membranes or free radicals. In doing so, metabolomics provided a more complete picture of changes in metabolism under hypoxia and heat stress. PMID:23604617

Verberk, W C E P; Sommer, U; Davidson, R L; Viant, M R

2013-04-19

47

Anaerobic Metabolism of Catechol by the Denitrifying Bacterium Thauera aromatica--a Result of Promiscuous Enzymes and Regulators?  

Microsoft Academic Search

The anaerobic metabolism of catechol (1,2-dihydroxybenzene) was studied in the betaproteobacterium Thauera aromatica that was grown with CO2 as a cosubstrate and nitrate as an electron acceptor. Based on different lines of evidence and on our knowledge of enzymes and genes involved in the anaerobic metabolism of other aromatic substrates, the following pathway is proposed. Catechol is converted to catechylphosphate

Bin Ding; Sirko Schmeling; Georg Fuchs

2008-01-01

48

Phosphoenolpyruvate metabolism in Teladorsagia circumcincta: a critical junction between aerobic and anaerobic metabolism.  

PubMed

Nematodes which have adapted to an anaerobic lifestyle in their adult stages oxidise phosphoenolpyruvate (PEP) to oxaloacetate rather than pyruvate as the final product of glycolysis. This adaptation involves selective expression of the enzyme phosphoenolpyruvate carboxykinase (PEPCK), instead of pyruvate kinase (PK). However, such adaptation is not absolute in aerobic nematode species. We have examined the activity and kinetics of PEPCK and PK in larvae (L(3)) and adults of Teladorsagia circumcincta, a parasite known to exhibit oxygen uptake. Results revealed that PK and PEPCK activity existed in both L(3)s and adults. The enzymes had differing affinity for nucleotide diphosphates: while both can utilise GDP, only PK utilised ADP and only PEPCK utilised IDP. In both life cycle stages, enzymes showed similar affinity for PEP. PK activity was predominant in both stages, although activity of this enzyme was lower in adults. When combined, both the activity levels and the enzyme kinetics showed that pyruvate production is probably favoured in both L(3) and adult stages of T. circumcincta and suggest that metabolism of PEP to oxaloacetate is a minor metabolic pathway in this species. PMID:22902746

Simcock, D C; Walker, L R; Pedley, K C; Simpson, H V; Brown, S

2012-08-10

49

Misconceptions about Aerobic and Anaerobic Energy Expenditure  

PubMed Central

The measurement of gas exchange has played an invaluable role in metabolic interpretation. The uptake of 1 liter of oxygen is often converted into an energy expenditure estimate of 21.1 kilojoules (e.g., 1 L O2 = 21.1 kJ or ~5 kcal). This article demonstrates both the importance of such a conversion and the potential for misinterpretation. Oxygen uptake during heavy and severe exercise will also be discussed.

Scott, Christopher

2005-01-01

50

Energetics of end product excretion in anaerobic bacteria and the metabolism of fatty acids by Syntrophomonas wolfei. Progress report, January 31December 15, 1985  

Microsoft Academic Search

This work addresses the metabolism of fatty acids and the energetics of growth of the anaerobic, syntrophic, fatty acid-degrading bacterium, Syntrophomonas wolfei. S. wolfei degrades Câ to Câ straight chain fatty acids to acetate and Hâ or acetate, propionate and Hâ; isoheptanoate is degraded to isovalerate, acetate, and Hâ. S. wolfei can not use any common bacterial energy source that

1985-01-01

51

Genomic insights into syntrophy: the paradigm for anaerobic metabolic cooperation.  

PubMed

Syntrophy is a tightly coupled mutualistic interaction between hydrogen-/formate-producing and hydrogen-/formate-using microorganisms that occurs throughout the microbial world. Syntrophy is essential for global carbon cycling, waste decomposition, and biofuel production. Reverse electron transfer, e.g., the input of energy to drive critical redox reactions, is a defining feature of syntrophy. Genomic analyses indicate multiple systems for reverse electron transfer, including ion-translocating ferredoxin:NAD(+) oxidoreductase and hydrogenases, two types of electron transfer flavoprotein:quinone oxidoreductases, and other quinone reactive complexes. Confurcating hydrogenases that couple the favorable production of hydrogen from reduced ferredoxin with the unfavorable production of hydrogen from NADH are present in almost all syntrophic metabolizers, implicating their critical role in syntrophy. Transcriptomic analysis shows upregulation of many genes without assigned functions in the syntrophic lifestyle. High-throughput technologies provide insight into the mechanisms used to establish and maintain syntrophic consortia and conserve energy from reactions that operate close to thermodynamic equilibrium. PMID:22803797

Sieber, Jessica R; McInerney, Michael J; Gunsalus, Robert P

2012-07-09

52

Anaerobic metabolism in the leech (Hirudo medicinalis L.): direct and indirect calorimetry during severe hypoxia.  

PubMed

Anaerobic metabolism in the limnic annelid Hirudo medicinalis L. was investigated by direct and indirect calorimetry. During long-term severe hypoxia, the rate of heat dissipation was reduced up to 13% of the aerobic rate. At the same time, the rate of ATP turnover was reduced to about 30% of the aerobic rate, indicating that metabolic depression is an important mechanism to ensure survival of the leech during environmental anaerobiosis. Heat dissipation during hypoxia was monitored under two experimental conditions, favouring either concomitant hypocapnia (continuous N2 bubbling) or hypercapnia (self-induced hypoxia). The reduction in heat dissipation during hypocapnic hypoxia was less pronounced than during hypercapnic hypoxia, indicating that the different experimental conditions may influence anaerobic metabolism and the extent of metabolic depression. Biochemical analysis of known anaerobic substrates and endproducts provided the basis for indirect calorimetry during self-induced hypoxia. From changes in metabolites, the expected heat dissipation was calculated for initial (0-8 ,h) and long-term severe hypoxia (8-72 h). During the initial period, the calculated heat dissipation fully accounted for direct calorimetric determination. During long-term hypoxia, only 71% of the measured heat production could be explained from biochemical analysis of metabolites. Therefore, an additional unknown endproduct cannot be excluded, especially when anaerobic ammonia production and analysis of the carbohydrate balance are considered. PMID:8765666

Schmidt, H; Wichmann, A; Lamprecht, I; Zerbst-Boroffka, I

1996-01-01

53

Exercise- and Hypoxia-Induced Anaerobic Metabolism and Recovery: A Student Laboratory Exercise Using Teleost Fish  

ERIC Educational Resources Information Center

|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…

Rees, B. B.; Boily, P.; Williamson, L. A. C.

2009-01-01

54

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

PubMed

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

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

2009-04-24

55

Regulation and Function of Versatile Aerobic and Anaerobic Respiratory Metabolism in Pseudomonas aeruginosa  

PubMed Central

Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO), and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article.

Arai, Hiroyuki

2011-01-01

56

Metabolic interactions between anaerobic bacteria in methanogenic environments  

Microsoft Academic Search

In methanogenic environments organic matter is degraded by associations of fermenting, acetogenic and methanogenic bacteria. Hydrogen and formate consumption, and to some extent also acetate consumption, by methanogens affects the metabolism of the other bacteria. Product formation of fermenting bacteria is shifted to more oxidized products, while acetogenic bacteria are only able to metabolize compounds when methanogens consume hydrogen and

Alfons J. M. Stams

1994-01-01

57

(Anaerobic metabolism of aromatic compounds by phototrophic bacteria: Biochemical aspects)  

SciTech Connect

Two aspects of the work proposed have received major emphasis during the period since the grant was activated: isolation and characterization of transposon insertion mutants of Rhodopseudomonas palusrtis defective in phototrophic growth on aromatic compounds, and attempts to purify and characterize the Coenzyme A ligase enzyme involved in activating 4-hydroxybenzoate. The HPLC apparatus was installed in August, and calibration of columns both for metabolite and for protein separations has been initiated. A start has also been made on synthesis of Coenzyme A thioesters of compounds that are potential intermediates in the anaerobic degradation pathways. 1 tab.

Gibson, J.

1989-01-01

58

Energy transduction by anaerobic ferric iron respiration in Thiobacillus ferrooxidans  

SciTech Connect

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.

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

1991-07-01

59

Anaerobic metabolism of nitroaromatic compounds by sulfate-reducing and methanogenic bacteria  

SciTech Connect

Ecological observations suggest that sulfate-reducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Most studies on the microbial metabolism of nitroaromatic compounds used aerobic microorganisms. In most cases no mineralization of nitroaromatics occurs, and only superficial modifications of the structures are reported. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds reportedly undergo a series of reductions with the formation of amino compounds. For example, trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of ammonia from triaminotoluene is achieved by reductive deamination catalyzed by the enzyme reductive deaminase, with the production of ammonia and toluene. Some sulfate reducers can metabolize toluene to CO{sub 2}. Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. Many methanogenic bacteria can reduce nitroaromatic compounds to amino compounds. In this paper we review the anaerobic metabolic processes of nitroaromatic compounds under sulfate-reducing And methanogenic conditions.

Boopathy, R. [Argonne National Lab., IL (United States); Kulpa, C.F. [Notre Dame Univ., IN (United States). Dept. of Biological Sciences

1994-06-01

60

Co-metabolic conversion of toluene in anaerobic n-alkane-degrading bacteria.  

PubMed

Diverse microorganisms have been described to degrade petroleum hydrocarbons anaerobically. Strains able to utilize n-alkanes do not grow with aromatic hydrocarbons, whereas strains able to utilize aromatic hydrocarbons do not grow with n-alkanes. To investigate this specificity in more detail, three anaerobic n-alkane degraders (two denitrifying, one sulfate-reducing) and eight anaerobic alkylbenzene degraders (five denitrifying, three sulfate-reducing) were incubated with mixtures of n-alkanes and toluene. Whereas the toluene degradationers formed only the characteristic toluene-derived benzylsuccinate and benzoate, but no n-alkane-derived metabolites, the n-alkane degraders formed toluene-derived benzylsuccinate, 4-phenylbutanoate, phenylacetate and benzoate besides the regular n-alkane-derived (1-methylalkyl)succinates and methyl-branched alkanoates. The co-metabolic conversion of toluene by anaerobic n-alkane degraders to the level of benzoate obviously follows the anaerobic n-alkane degradation pathway with C-skeleton rearrangement and decarboxylation rather than the ?-oxidation pathway of anaerobic toluene metabolism. Hence, petroleum-derived aromatic metabolites detectable in anoxic environments may not be exclusively formed by genuine alkylbenzene degraders. In addition, the hitherto largely unexplored fate of fumarate hydrogen during the activation reactions was examined with (2,3-(2) H(2) )fumarate as co-substrate. Deuterium was completely exchanged with hydrogen at the substituted carbon atom (C-2) of the succinate adducts of n-alkanes, whereas it is retained in toluene-derived benzylsuccinate, regardless of the type of enzyme catalysing the fumarate addition reaction. PMID:21880102

Rabus, Ralf; Jarling, René; Lahme, Sven; Kühner, Simon; Heider, Johann; Widdel, Friedrich; Wilkes, Heinz

2011-08-22

61

Molecular Basis for Anaerobic Growth of Saccharomyces cerevisiae on Xylose, Investigated by Global Gene Expression and Metabolic Flux Analysis  

Microsoft Academic Search

Yeast xylose metabolism is generally considered to be restricted to respirative conditions because the two-step oxidoreductase reactions from xylose to xylulose impose an anaerobic redox imbalance. We have recently developed, however, a Saccharomyces cerevisiae strain that is at present the only known yeast capable of anaerobic growth on xylose alone. Using transcriptome analysis of aerobic chemostat cultures grown on xylose-glucose

Marco Sonderegger; Marie Jeppsson; Barbel Hahn-Hagerdal; Uwe Sauer

2004-01-01

62

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

NSDL National Science Digital Library

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.

B B Rees (University of New Orleans Biological Sciences); P Boily (Western Connecticut State University/University of New Orleans Biology and Environmental Sciences); L A.C. Williamson (University of New Orleans Biological Sciences)

2009-03-01

63

Effects of a commercially available energy drink on anaerobic performance  

Microsoft Academic Search

In an attempt to improve aerobic and anaerobic performance, athletes and fitness enthusiasts consume a variety of supplements. Because of this, energy drinks are quickly becoming more and more popular every day. Despite its highly addictive nature, caffeine, which is the main active ingredient in energy drinks, is gaining recognition as an ergogenic aid. However, due to the many factors

Jason J Downing

2009-01-01

64

Anaerobic metabolism of phenol in proteobacteria and further studies of phenylphosphate carboxylase  

Microsoft Academic Search

Anaerobic phenol metabolism was studied in three facultative aerobic denitrifying bacteria, Thauera aromatica, “Aromatoleum aromaticum” strain EbN1 (Betaproteobacteria), and Magnetospirillum sp. (Alphaproteobacterium). All species formed phenylphosphate and contained phenylphosphate carboxylase but not phenol carboxylase\\u000a activity. This is in contrast to direct phenol carboxylation by fermenting bacteria. Antisera raised against subunits of the\\u000a Thauera phenylphosphate synthase and phenylphosphate carboxylase partly cross-reacted

Sirko Schmeling; Georg Fuchs

2009-01-01

65

Xylose metabolism in the anaerobic fungus Piromyces sp. strain E2 follows the bacterial pathway  

Microsoft Academic Search

The anaerobic fungus Piromyces sp. strain E2 metabolizes xylose via xylose isomerase and d-xylulokinase as was shown by enzymatic and molecular analyses. This resembles the situation in bacteria. The clones encoding the two enzymes were obtained from a cDNA library. The xylose isomerase gene sequence is the first gene of this type reported for a fungus. Northern blot analysis revealed

Harry R. Harhangi; Anna S. Akhmanova; Roul Emmens; Chris van der Drift; Johannes P. van Dijken; Mike S. M. Jetten; Jack T. Pronk

2003-01-01

66

Anaerobic metabolism of immediate methane precursors in Lake Mendota.  

PubMed Central

Lake Mendota sediments and the immediate overlying water column were studied to better understand the metabolism of the methanogenic precursors H2/CO2 and acetate in nature. The pool size of acetate (3.5 microns M) was very small, and the acetate turnover time (0.22h) was very rapid. The dissolved inorganic carbon pool was shown to be large (6.4 to 8.3 mM), and the turnover time was slow (111 H.). CO2 was shown to account for 41 +/- 5.5% of the methane produced in sediment. Acetate and H2/CO2 were simultaneously converted to CH4. The addition of H2 to sediments resulted in an increase specific activity of CH4 from H(14)CO3- and a decrease in specific activity of CH4 from [2-14C]acetate. Acetate addition resulted in a decrease in specific activity of CH4 from H(14)CO3-. The metabolism of H(14)CO3- or [2-14C]acetate to 14CH4 was not inhibited by addition of acetate or H2. After greater than 99% of added [2-14C]acetate had been turned over, 42% of the label was recovered as 14CH4 20% was recovered as 14CO2 and 38% was incorporated into sediment. Inhibitor studies of [2-14C]acetate metabolism in sediments demonstrated that CHCl3 completely inhibited CH4 formation, but not CO2 production. Air and nitrate addition inhibited CH4 formation and stimulated CO2 production, whereas fluoroacetate addition totally inhibited acetate metabolism. The oxidation of [2-14C]acetate to 14CO2 was shown to decrease with time when sediment was incubated before the addition of label, suggesting depletion of low levels of an endogenous sediment electron acceptor. Acetate metabolism varied seasonally and was related to the concentration of sulfate in the lake and interstitial water. Methanogenesis occurred in the sediment and in the water immediately overlying the sediment during period of lake stratification and several centimeters below the sediment-water interface during lake turnovers. These data indicate that methanogenesis in Lake Mendota sediments was limited by "immediate" methane precursor availability (i.e., acetate and H2), by competition for these substrates by nonmethanogens, and by seasonal variations which altered sediment and water chemistry.

Winfrey, M R; Zeikus, J G

1979-01-01

67

Aromatic and Volatile Acid Intermediates Observed during Anaerobic Metabolism of Lignin-Derived Oligomers  

PubMed Central

Anaerobic enrichment cultures acclimated for 2 years to use a 14C-labeled, lignin-derived substrate with a molecular weight of 600 as a sole source of carbon were characterized by capillary and packed column gas chromatography. After acclimation, several of the active methanogenic consortia were inhibited with 2-bromoethanesulfonic acid, which suppressed methane formation and enhanced accumulation of a series of metabolic intermediates. Volatile fatty acids levels in 2-bromoethanesulfonic acid-amended cultures were 10 times greater than those in the uninhibited, methane-forming consortia with acetate as the predominant component. Furthermore, in the 2-bromoethanesulfonic acid-amended consortia, almost half of the original substrate carbon was metabolized to 10 monoaromatic compounds, with the most appreciable quantities accumulated as cinnamic, benzoic, caffeic, vanillic, and ferulic acids. 2-Bromoethanesulfonic acid seemed to effectively block CH4 formation in the anaerobic food chain, resulting in the observed buildup of volatile fatty acids and monoaromatic intermediates. Neither fatty acids nor aromatic compounds were detected in the oligolignol substrate before its metabolism, suggesting that these anaerobic consortia have the ability to mediate the cleavage of the ?-aryl-ether bond, the most common intermonomeric linkage in lignin, with the subsequent release of the observed constituent aromatic monomers.

Colberg, P. J.; Young, L. Y.

1985-01-01

68

Aromatic and volatile acid intermediates observed during anaerobic metabolism of lignin-derived oligomers  

SciTech Connect

Anaerobic enrichment cultures acclimated for 2 years to use a /sup 14/C-labeled, lignin-derived substrate with a molecular weight of 600 as a sole source of carbon were characterized by capillary and packed column gas chromatography. After acclimation, several of the active methanogenic organisms were inhibited with 2-bromoethanesulfonic acid, which suppressed methane formation and enhanced accumulation of a series of metabolic intermediates. Volatile fatty acids levels in 2-bromoethansulfonic acid-amended cultures were 10 times greater than those in the uninhibited, methane-forming organisms with acetate as the predominant component. Furthermore, in the 2-bromoethanesulfonic acid-amended organisms, almost half of the original substrate carbon was metabolized to 10 monaromatic compounds, with the most appreciable quantities accumulated as cinnamic, benzoic, caffeic, vanillic, and ferulic acids. 2-Bromoethanesulfonic acid seemed to effectively block CH/sub 4/ formation in the anaerobic food chain, resulting in the observed buildup of volatile fatty acids and monoaromatic intermediates. Neither fatty acids nor aromatic compounds were detected in the oligolignol substrate before its metabolism, suggesting that these anaerobic organisms have the ability to mediate the cleavage of the ..beta..-aryl-ether bond, the most common intermonomeric linkage in lignin, with the subsequent release of the observed constituent aromatic monomers.

Colberg, P.J.; Young, L.Y.

1985-02-01

69

The effects of aerobic and anaerobic exercise conditioning on resting metabolic rate and the thermic effect of a meal.  

PubMed

This study examined resting metabolic rate (RMR) and thermic effect of a meal (TEM) among athletes who had participated in long-term anaerobic or aerobic exercise. Nine collegiate wrestlers were matched for age, weight, and fat-free weight with 9 collegiate swimmers. Preliminary testing included maximal oxygen consumption, maximal anaerobic capacity (MAnC) for both the arms and the legs, and percent body fat. On two separate occasions, RMR and TEM were measured using indirect calorimetry. VO2max was significantly higher in the swimmers while MAnC was significantly higher in the wrestlers for both the arms and the legs. RMR adjusted for fat-free weight was not significantly different between groups. The differences in total and percentage of TEM between the groups were not statistically significant, and there were no differences in baseline thyroid hormones. These data suggest that despite significant differences in VO2max and WAnT values following long-term aerobic and anaerobic exercise training, resting energy expenditure does not differ between these college athletes. PMID:7874150

Schmidt, W D; Hyner, G C; Lyle, R M; Corrigan, D; Bottoms, G; Melby, C L

1994-12-01

70

Fermentative metabolism of pyruvate by Rhodospirillum rubrum after anaerobic growth in darkness.  

PubMed Central

Rhodospirillum rubrum grew anaerobically in darkness and fermented sodium pyruvate by a pyruvate formate-lyase reaction. During 30 min of anaerobic dark or light incubation with sodium pyrivate, crude extracts from fermentatively grown cells produced about 6 micronmol of acetylphosphate and formate per mg of protein in reactions performed at pH 8.3. Cell extracts also catalyzed the exchange of sodium [14C]formate into sodium pyruvate at an apparent pH optimum of 7.3 to 7.5, but only about 2.5 micronmol of acetylphosphate was produced at this lower pH value. R. rubrum may also form pyruvate:ferredoxin oxidoreductase activity, as evidenced by low bicarbonate exchange activity. However, its participation in pyruvate metabolism in anaerobic dark-grown cells was not understood. During anaerobic, dark growth with pyruvate, formate was an intermediate in H2 and CO2 gas evolution. In contrast with H2 production by a light-dependent H2-nitrogenase system in photosynthetically grown cells, H2 formation in fermenting R. rubrum occurred through a carbon monoxide-sensitive formic hydrogenlyase reaction not influenced by light.

Gorrell, T E; Uffen, R L

1977-01-01

71

Anaerobic metabolism in aerobic mammalian cells: information from the ratio of calorimetric heat flux and respirometric oxygen flux.  

PubMed

Calorimetric and respirometric studies of cultured cells show that both neoplastic and non-neoplastic cell types maintain an anaerobic contribution to their total heat flux. In many mammalian cells this can be explained quantitatively by lactate production observed under fully aerobic conditions. Uncoupling and enhanced futile substrate cycling increase the ratio of heat flux to oxygen flux, the calorimetric-respirometric (CR) ratio. The interpretation of calorimetric and respirometric measurements requires an energy balance approach in which experimentally measured CR ratios are compared with thermochemically derived oxycaloric equivalents. The oxycaloric equivalent is the enthalpy change per mole of oxygen consumed, and equals -470 kJ/mol O2 in the aerobic catabolism of glucose, assuming that catabolism is 100% dissipative (the net efficiency of metabolic heat transformation is zero). CR ratios more negative than -470 kJ/mol O2 have been reported in well-oxygenated cell cultures and are discussed in terms of integrated aerobic and anaerobic metabolism. PMID:2184896

Gnaiger, E; Kemp, R B

1990-04-26

72

Heat and energy requirements in thermophilic anaerobic sludge digestion  

Microsoft Academic Search

The heating requirements of the thermophilic anaerobic digestion process were studied. Biogas production was studied in laboratory experiments at retention times from 1 to 10 days. The data gathered in the experiments was then used to perform a heat and energy analysis. The source of heat was a conventional CHP unit system. The results showed that thermophilic digestion is much

G. D. Zupan?i?; M. Roš

2003-01-01

73

Energy recovery from alcohol stillage using anaerobic filters  

SciTech Connect

Ethanol production from grains requires substantial quantities of water. Much of the water used in this fermentation process becomes mixed with grain solids and the product stillage must be treated before disposal. The anaerobic filter process offers the advantages of both efficient waste stillage treatment and energy recovery as methane gas. A pilot-scale anaerobic filter (0.5 m in diameter and 2.0 m high) was used to treat a synthesized stillage. This anaerobic filter proved quite effective. Treatment efficiencies as high as 90% were observed when operating at a chemical oxygen demand (COD) loading rate of 2.0 kg/m/sup 3/ day and influent COD concentration of 3000 mg/L. This research is continuing and COD loading rates as high as 8.0 kg/m/sup 3/ day and influent concentration as high as 12,000 mg/L are planned.

Dahab, M.F.; Young, J.C.

1981-01-01

74

Energy and macronutrient metabolism.  

PubMed

In general, obesity is a state of high energy stores, high energy intake, and high energy expenditure. The high energy expenditure is largely due to the increased fat-free mass. The failure to find a positive relationship between reported energy intake and body size reflects a greater under-reporting of calorie intake among obese individuals. Obesity, therefore, develops as a consequence of a chronic imbalance between intake and expenditure, although the cause of this is not apparent from the energy balance equation. However, this equation can be dissected into its component nutrient balance equations because net de novo lipogenesis is negligible in free-living humans. Fat calories are handled very differently from non-fat calories. Non-fat nutrient oxidation rates rise and fall to match the fluctuations in non-fat intake so that non-fat calorie balance is actively maintained. In contrast, changes in fat intake do not acutely affect fat oxidation but are matched by changes in storage. Therefore, within the fat balance equation there is ample scope for a chronic imbalance between fat intake and oxidation. Also, there is some evidence that carbohydrate balance may be an important signal for hunger and satiety. These concepts imply that, under free-living, ad libitum eating conditions, changes in nutrient intake composition (e.g. an increased proportion of fat in the diet) or changes in nutrient oxidation composition (e.g. a decrease in the proportion of fat oxidized) will lead to body weight change (in these cases, to weight gain). Considering obesity as a consequence of normal physiology (with its normal variation between individuals) in a 'pathological' environment (high fat diet, low exercise) offers an important perspective for explaining the interpopulation and interindividual differences in obesity and for formulating treatment and prevention options. Low energy expenditure (relative to body size), high respiratory quotient and insulin sensitivity have been shown to be predictors of weight gain, although upon gaining weight these metabolic factors tend to 'normalize'. Metabolic responses to underfeeding or overfeeding are largely predictable from the changes in calorie intake and changes in body composition, but some adaptive changes may occur. PMID:7980346

Swinburn, B A; Ravussin, E

1994-07-01

75

Anaerobic citrate metabolism and its regulation in enterobacteria  

Microsoft Academic Search

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

M. Bott

1997-01-01

76

Flexibility in Anaerobic Metabolism as Revealed in a Mutant of Chlamydomonas reinhardtii Lacking Hydrogenase Activity  

SciTech Connect

The green alga Chlamydomonas reinhardtii has a network of fermentation pathways that become active when cells acclimate to anoxia. Hydrogenase activity is an important component of this metabolism, and we have compared metabolic and regulatory responses that accompany anaerobiosis in wild-type C. reinhardtii cells and a null mutant strain for the HYDEF gene (hydEF-1 mutant), which encodes an [FeFe] hydrogenase maturation protein. This mutant has no hydrogenase activity and exhibits elevated accumulation of succinate and diminished production of CO2 relative to the parental strain during dark, anaerobic metabolism. In the absence of hydrogenase activity, increased succinate accumulation suggests that the cells activate alternative pathways for pyruvate metabolism, which contribute to NAD(P)H reoxidation, and continued glycolysis and fermentation in the absence of O2. Fermentative succinate production potentially proceeds via the formation of malate, and increases in the abundance of mRNAs encoding two malateforming enzymes, pyruvate carboxylase and malic enzyme, are observed in the mutant relative to the parental strain following transfer of cells from oxic to anoxic conditions. Although C. reinhardtii has a single gene encoding pyruvate carboxylase, it has six genes encoding putative malic enzymes. Only one of the malic enzyme genes, MME4, shows a dramatic increase in expression (mRNA abundance) in the hydEF-1 mutant during anaerobiosis. Furthermore, there are marked increases in transcripts encoding fumarase and fumarate reductase, enzymes putatively required to convert malate to succinate. These results illustrate the marked metabolic flexibility of C. reinhardtii and contribute to the development of an informed model of anaerobic metabolism in this and potentially other algae.

Dubini, A.; Mus, F.; Seibert, M.; Grossman, A. R.; Posewitz, M. C.

2009-03-13

77

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

PubMed Central

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.

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

2004-01-01

78

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

Microsoft Academic Search

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

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

1999-01-01

79

Carboxylation as an initial reaction in the anaerobic metabolism of naphthalene and phenanthrene by sulfidogenic consortia.  

PubMed Central

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 muM) was observed after 150 days of incubation. Upon refeeding, NAP and PHE were utilized within 14 days. The utilization of both compounds was inhibited in the presence of 20 mM molybdate. [14C]NAP and [14C]PHE were mineralized to 14CO2. The activities could be maintained and propagated by subculturing in mineral medium. In the presence of halogenated analogs, 2-naphthoate was detected in NAP-utilizing enrichments. The mass spectrum of the derivatized 2-napththoate from the enrichment supplemented with both [13C]bicarbonate and NAP indicates the incorporation of 13CO2 into NAP. In the PHE-utilizing enrichment, a metabolite was detected by both high-pressure liquid chromatography and gas chromatography-mass spectrometry analyses. The molecular ion and fragmentation pattern of its mass spectrum indicate that it was phenanthrenecarboxylic acid. The results obtained with [13C] bicarbonate indicate that 13CO2 was incorporated into PHE. It appears, therefore, that carboxylation is an initial key reaction for the anaerobic metabolism and NAP and PHE. To our knowledge, this is the first report providing evidence for intermediates of PAH degradation under anaerobic conditions.

Zhang, X; Young, L Y

1997-01-01

80

Metabolic energy required for flight  

NASA Astrophysics Data System (ADS)

This paper reviews data available from U.S. and U.S.S.R. studies on energy metabolism in the microgravity of space flight. Energy utilization and energy availability in space seem to be similar to those on Earth. However, negative nitrogen balances in space in the presence of adequate energy and protein intakes and in-flight exercise, suggest that lean body mass decreases in space. Metabolic studies during simulated (bed rest) and actual microgravity have shown changes in blood glucose, fatty acids, and insulin levels, suggesting that energy metabolism may be altered during flight. Future research should focus on the interactions of lean body mass, diet, and exercise in space and their roles in energy metabolism during space flight.

Lane, H. W.; Gretebeck, R. J.

1994-11-01

81

Combining Anaerobic Digestion and Waste-To-Energy  

Microsoft Academic Search

A large fraction of the municipal solid wastes (MSW) stream in the U.S. comprises of natural organic compounds (i.e., food and plant wastes) with high moisture content and low heating value. While these properties are undesirable during the combustion of MSW in waste-to-energy (WTE) plants, they are required for anaerobic digestion (AD). During AD, methane gas is produced that can

KARENA M. OSTREM; KARSTEN MILLRATH; NICKOLAS J. THEMELIS

82

Metagenomic insights into anaerobic metabolism along an Arctic peat soil profile.  

PubMed

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

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

2013-05-31

83

Metabolic Behavior and Enzymatic Aspects of Denitrifying EBPR Sludge in a Continuous-Flow Anaerobic-Anoxic System.  

PubMed

The metabolic aspects of enhanced biological phosphorus removal (EBPR) were investigated for the first time in a continuous-flow anaerobic-anoxic plant fed with acetate, propionate, or substrates which are involved in the tricarboxylic acid and/or glyoxylate cycle, i.e., fumarate, malate, or oxaloacetate, as the sole carbon source. Although the polyphosphate-accumulating organisms (PAOs) population remained stable with any carbon source examined, no typical EBPR metabolism was observed during fumarate, malate, or oxaloacetate utilization. Specific enzymatic activities related to EBPR were determined in activated sludge homogenates and directly correlated with the nutrient metabolic rates. The experimental results indicated the direct involvement of alkaline phosphatase, pyrophosphatase, and exopolyphosphatase in the denitrifying EBPR process. Metabolic aspects of glyoxylate cycle enzymes are discussed with regard to the biomass anaerobic and anoxic activity. Process performance was highly influenced by the kind of substrate utilized, indicating that specific metabolic pathways should be followed to favor efficient EBPR. PMID:23912208

Zafiriadis, Ilias; Ntougias, Spyridon; Kapagiannidis, Anastasios G; Aivasidis, Alexander

2013-08-04

84

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

Microsoft Academic Search

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

Jean-Pierre Kaiser; Kurt W. Hanselmann

1982-01-01

85

Exercise-and Hypoxia-Induced Anaerobic Metabolism and Recovery: A Student Laboratory Exercise Using Teleost Fish  

Microsoft Academic Search

Anaerobic metabolism is recruitedin 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

Bernard Rees; P. Boily; L. A. C. Williamson

2009-01-01

86

The effect of endosymbiotic methanogens on the growth and metabolic profile of the anaerobic free-living ciliate Trimyema compressum  

Microsoft Academic Search

We examined the influence of endosymbiotic methanogens on the growth and metabolic profile of the anaerobic ciliate Trimyema compressum. When we isolated the ciliate, it possessed a large number of endosymbiotic Methanobacterium-like methanogens inside the cell. The culture was transferred to fresh medium with Lactobacillus sp. cells as food bacteria. T. compressum grew to give a maximum cell number of

Kazutaka Yamada; Yoichi Kamagata; Kazunori Nakamura

1997-01-01

87

Microbial metabolism of pyridine, quinoline, acridine, and their derivatives under aerobic and anaerobic conditions.  

PubMed Central

Our review of the metabolic pathways of pyridines and aza-arenes showed that biodegradation of heterocyclic aromatic compounds occurs under both aerobic and anaerobic conditions. Depending upon the environmental conditions, different types of bacteria, fungi, and enzymes are involved in the degradation process of these compounds. Our review indicated that different organisms are using different pathways to biotransform a substrate. Our review also showed that the transformation rate of the pyridine derivatives is dependent on the substituents. For example, pyridine carboxylic acids have the highest transformation rate followed by mono-hydroxypyridines, methylpyridines, aminopyridines, and halogenated pyridines. Through the isolation of metabolites, it was possible to demonstrate the mineralization pathway of various heterocyclic aromatic compounds. By using 14C-labeled substrates, it was possible to show that ring fission of a specific heterocyclic compound occurs at a specific position of the ring. Furthermore, many researchers have been able to isolate and characterize the microorganisms or even the enzymes involved in the transformation of these compounds or their derivatives. In studies involving 18O labeling as well as the use of cofactors and coenzymes, it was possible to prove that specific enzymes (e.g., mono- or dioxygenases) are involved in a particular degradation step. By using H2 18O, it could be shown that in certain transformation reactions, the oxygen was derived from water and that therefore these reactions might also occur under anaerobic conditions.

Kaiser, J P; Feng, Y; Bollag, J M

1996-01-01

88

One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production. Progress report, June 1990--May 1992  

SciTech Connect

This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. (CBS)

Zeikus, J.G.; Jain, M.K.

1992-04-01

89

Energy metabolism in tennis  

Microsoft Academic Search

Physiological responses of a group of 16 tennis players have been investigated under the almost natural conditions of a 10 min long training match. Collecting the expired air into Douglas bags, transmitting heart rate all the time of experiment wirelessly and analysing every player's activity we have got following main results:The average intensity of metabolism was 919.5% BMR, that is

V. Seliger; M. Ejem; M. Pauer; V. Šafa?ík

1973-01-01

90

Some Aspects of Yeast Anaerobic Metabolism Examined by the Inhibition of Pyruvate Decarboxylase  

NASA Astrophysics Data System (ADS)

Incubation of yeast cells with various sugars in aqueous alkaline phosphate solutions under anaerobic conditions results in the accumulation of pyruvate in the cell medium after short periods of up to 15 minutes. This accumulation of pyruvate as the end product of glycolysis results from the inhibition of pyruvate decarboxylase under the conditions. This pyruvate production can be readily measured in the cell-free medium by a spectrophotometric assay using lactic dehydrogenase and NADH. The production of pyruvate can be directly related to the ability of the yeast cells to metabolize particular carbon sources provided. Comparison of pyruvate production by yeast from a variety of common sugars, for example, provides students with a means to assess what sugars are readily utilized by this organism. An additional advantage for student laboratory studies is the availability of Sacchromyces cerevisiae at minimal cost as dry granules which are easily weighed and quickly activated.

Martin, Earl V.

1998-10-01

91

Biogas generation potential by anaerobic digestion for sustainable energy development in India  

Microsoft Academic Search

The potential of biogas generation from anaerobic digestion of different waste biomass in India has been studied. Renewable energy from biomass is one of the most efficient and effective options among the various other alternative sources of energy currently available. The anaerobic digestion of biomass requires less capital investment and per unit production cost as compared to other renewable energy

P. Venkateswara Rao; Saroj S. Baral; Ranjan Dey; Srikanth Mutnuri

2010-01-01

92

PPARs: diverse regulators in energy metabolism and metabolic diseases  

Microsoft Academic Search

The nuclear receptor PPARs are fundamentally important for energy homeostasis. Through their distinct yet overlapping functions and tissue distribution, the PPARs regulate many aspects of energy metabolism at the transcriptional level. Functional impairment or dysregulation of these receptors leads to a variety of metabolic diseases, while their ligands offer many metabolic benefits. Studies of these receptors have advanced our knowledge

Yong-Xu Wang

2010-01-01

93

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

NASA Astrophysics Data System (ADS)

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.

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

1999-11-01

94

Kinetics of Butyrate, Acetate, and Hydrogen Metabolism in a Thermophilic, Anaerobic, Butyrate-Degrading Triculture  

PubMed Central

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, Km, for butyrate, acetate, and dissolved hydrogen were 76 ?M, 0.4 mM, and 8.5 ?M, respectively. Butyrate and hydrogen were metabolized to a concentration of less than 1 ?M, whereas acetate uptake usually ceased at a concentration of 25 to 75 ?M, indicating a threshold level for acetate uptake. No significant differences in Km 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.

Ahring, Birgitte K.; Westermann, Peter

1987-01-01

95

Anaerobic Metabolism of Aromatic Compounds by Phototrophic Bacteria: Progress Report, Year 2.  

National Technical Information Service (NTIS)

Various aromatic compounds can be broken down anaerobically by a microorganism, Rhodopseudomonas palustris. These results show that R. palustris is one of the most versatile of the anaerobic bacteria described to date with respect to aromatic degradation....

C. S. Harwood

1988-01-01

96

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

Microsoft Academic Search

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

M. Alexandra De; O. A. OConnor; David S. Kosson

1994-01-01

97

Carboxylation of phenylphosphate by phenol carboxylase, an enzyme system of anaerobic phenol metabolism.  

PubMed Central

Several lines of evidence indicate that the first step in the anaerobic metabolism of phenol is phenol carboxylation to 4-hydroxybenzoate; this reaction is considered a biological Kolbe-Schmitt carboxylation. A phenol carboxylase system was characterized by using a denitrifying Pseudomonas strain, K 172, which catalyzes an isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate. The enzymatic isotope exchange activity (100 nmol min-1 mg-1 of protein) requires Mn2+ and K+. We show that this system also catalyzes the carboxylation of phenylphosphate (the phosphoric acid monophenyl ester) to 4-hydroxybenzoate and phosphate. The specific activity of phenylphosphate carboxylation at the optimal pH of 6.5 is 12 nmol of CO2 fixed min-1 mg-1 of protein. Phenylphosphate cannot be replaced by Mg(2+)-ATP and phenol. The carboxylase activity requires Mn2+ but, in contrast to the isotope exchange activity, does not require K+. The apparent Km values are 1.5 mM dissolved CO2 and 0.2 mM phenylphosphate. Several convenient assays for phenylophosphate carboxylation are described. The isotope exchange reaction and the net carboxylation reaction are catalyzed by the same oxygen-sensitive enzyme, which has a half-life in an air-saturated solution of less than 1 min. Both activities cochromatographed with a protein with a Mr of 280,000, and both activities were induced only after anaerobic growth on phenol. The carboxylation of phenylphosphate suggests that phenylphosphate itself is the physiological CO2 acceptor molecular of this novel CO2 fixation reaction. Alternatively, phenylphosphate could simulate the unknown natural precursor. It is suggested that the formation of an enzyme-bound phenolate anion from the activated phenolic compound is the rate-determining step in the carboxylation reaction.

Lack, A; Fuchs, G

1992-01-01

98

Carboxylation of phenylphosphate by phenol carboxylase, an enzyme system of anaerobic phenol metabolism.  

PubMed

Several lines of evidence indicate that the first step in the anaerobic metabolism of phenol is phenol carboxylation to 4-hydroxybenzoate; this reaction is considered a biological Kolbe-Schmitt carboxylation. A phenol carboxylase system was characterized by using a denitrifying Pseudomonas strain, K 172, which catalyzes an isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate. The enzymatic isotope exchange activity (100 nmol min-1 mg-1 of protein) requires Mn2+ and K+. We show that this system also catalyzes the carboxylation of phenylphosphate (the phosphoric acid monophenyl ester) to 4-hydroxybenzoate and phosphate. The specific activity of phenylphosphate carboxylation at the optimal pH of 6.5 is 12 nmol of CO2 fixed min-1 mg-1 of protein. Phenylphosphate cannot be replaced by Mg(2+)-ATP and phenol. The carboxylase activity requires Mn2+ but, in contrast to the isotope exchange activity, does not require K+. The apparent Km values are 1.5 mM dissolved CO2 and 0.2 mM phenylphosphate. Several convenient assays for phenylophosphate carboxylation are described. The isotope exchange reaction and the net carboxylation reaction are catalyzed by the same oxygen-sensitive enzyme, which has a half-life in an air-saturated solution of less than 1 min. Both activities cochromatographed with a protein with a Mr of 280,000, and both activities were induced only after anaerobic growth on phenol. The carboxylation of phenylphosphate suggests that phenylphosphate itself is the physiological CO2 acceptor molecular of this novel CO2 fixation reaction. Alternatively, phenylphosphate could simulate the unknown natural precursor. It is suggested that the formation of an enzyme-bound phenolate anion from the activated phenolic compound is the rate-determining step in the carboxylation reaction. PMID:1592817

Lack, A; Fuchs, G

1992-06-01

99

Transformations of Halogenated Aromatic Aldehydes by Metabolically Stable Anaerobic Enrichment Cultures  

PubMed Central

Metabolically stable enrichment cultures of anaerobic bacteria obtained by elective enrichment of sediment samples from the Baltic Sea and Gulf of Bothnia have been used to study the oxidation and reduction of the aldehyde group of various halogenated aromatic aldehydes. During the transformation of 5- and 6-chlorovanillin, 6-bromovanillin, 3-chloro-4-hydroxybenzaldehyde, 3,5-dichloro-4-hydroxybenzaldehyde, and 3,5-dibromo-4-hydroxybenzaldehyde, it was shown that synthesis of the corresponding carboxylic acids, which were the principal metabolites, was invariably accompanied by partial reduction of the aldehyde to a hydroxymethyl group in yields of between 3 and 30%. Complete reduction to a methyl group was observed with some of the halogenated vanillins, but to an extremely limited extent with the halogenated 4-hydroxybenzaldehydes. One consortium produced both the hydroxymethyl and methyl compounds from both 5- and 6-chlorovanillin: it was therefore assumed that the methyl compound was the ultimate reduction product. On the basis of the kinetics of formation of the metabolites, it was concluded that the oxidation and reduction reactions were mechanistically related. In addition to these oxidations and reductions, dehalogenation was observed with one of the consortia. In contrast to the transformations of 5- and 6-chlorovanillin, which produced chlorinated methylcatechols, the corresponding compounds were not observed with 5- and 6-bromovanillin: the former was debrominated, forming 4-methylcatechol, whereas the latter produced 6-bromovanillyl alcohol without demethylation. Similarly, although 3-chloro-4-hydroxybenzaldehyde formed the chlorinated carboxylic acid and the benzyl alcohol, the 3-bromo compound was debrominated with formation of 4-hydroxybenzoic acid and, ultimately, phenol. On prolonged incubation, the halogenated carboxylic acids were generally decarboxylated, so that the final products from these substrates were halogenated catechols or phenols. Reductive processes of the type revealed in this study might therefore plausibly occur in the environment during anaerobic transformation of halogenated aromatic aldehydes containing hydroxyl and/or methoxyl groups.

Neilson, Alasdair H.; Allard, Ann-Sofie; Hynning, Per-Ake; Remberger, Mikael

1988-01-01

100

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

SciTech Connect

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-(CH/sub 2/-CH/sub 2/-O-)/sub n/H). 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-(CH/sub 2/-CH/sub 2/-CH/sub 2/-O-)/sub n/H) 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 PGI could not dehydrogenate long polymers of PEG (less than or equal to1000 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 polymerase substrates. This indicated that the bacterium could not convert PEG to a product suitable for uptake.

Dwyer, D.F.; Tiedje, J.M.

1986-10-01

101

Aerobic and anaerobic metabolism in oxygen minimum layer fishes: the role of alcohol dehydrogenase.  

PubMed

Zones of minimum oxygen form at intermediate depth in all the world's oceans as a result of global circulation patterns that keep the water at oceanic mid-depths out of contact with the atmosphere for hundreds of years. In areas where primary production is very high, the microbial oxidation of sinking organic matter results in very low oxygen concentrations at mid-depths. Such is the case with the Arabian Sea, with O(2) concentrations reaching zero at 200 m and remaining very low (<0.1 ml O(2)l(-1)) for hundreds of meters below this depth, and in the California borderland, where oxygen levels reach 0.2 ml O(2)l(-1) at 700 m with severely hypoxic (<1.0 ml O(2)l(-1)) waters at depths 300 m above and below that. Despite the very low oxygen, mesopelagic fishes (primarily lanternfishes: Mytophidae) inhabiting the Arabian Sea and California borderland perform a daily vertical migration into the low-oxygen layer, spending daylight hours in the oxygen minimum zone and migrating upward into normoxic waters at night. To find out how fishes were able to survive their daily sojourns into the minimum zone, we tested the activity of four enzymes, one (lactate dehydrogenase, LDH) that served as a proxy for anaerobic glycolysis with a conventional lactate endpoint, a second (citrate synthase, CS) that is indicative of aerobic metabolism, a third (malate dehydrogenase) that functions in the Krebs' cycle and as a bridge linking mitochondrion and cytosol, and a fourth (alcohol dehydrogenase, ADH) that catalyzes the final reaction in a pathway where pyruvate is reduced to ethanol. Ethanol is a metabolic product easily excreted by fish, preventing lactate accumulation. The ADH pathway is rarely very active in vertebrate muscle; activity has previously been seen only in goldfish and other cyprinids capable of prolonged anaerobiosis. Activity of the enzyme suite in Arabian Sea and California fishes was compared with that of ecological analogs in the same family and with the same lifestyle but living in systems with much higher oxygen concentrations: the Gulf of Mexico and the Southern Ocean. ADH activities in the Arabian Sea fishes were similar to those of goldfish, far higher than those of confamilials from the less severe minimum in the Gulf of Mexico, suggesting that the Arabian Sea fishes are capable of exploiting the novel ethanol endpoint to become competent anaerobes. In turn, the fishes of California exhibited a higher ADH activity than their Antarctic relatives. It was concluded that ADH activity is more widespread in fishes than previously believed and that it may play a role in allowing vertically migrating fishes to exploit the safe haven afforded by severe oxygen minima. PMID:22573769

Torres, Joseph J; Grigsby, Michelle D; Clarke, M Elizabeth

2012-06-01

102

In situ detection of anaerobic alkane metabolites in subsurface environments.  

PubMed

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

Agrawal, Akhil; Gieg, Lisa M

2013-06-04

103

Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source  

Microsoft Academic Search

Inthemicrobial competition observedinenhanced biological phosphorusremoval(EBPR) systems, an undesirable group of micro-organisms known as glycogen-accumulating organisms (GAOs) compete for carbon in the anaerobic period with the desired polyphosphate-accumulating organisms (PAOs). Some studies have suggested that a propionate carbon source provides PAOs with acompetitive advantage over GAOs in EBPRsystems; however, the metabolism ofGAOs with this carbon source has not been previously investigated.

Adrian Oehmen; Raymond J. Zeng; Aaron M. Saunders; Linda L. Blackall; Jurg Keller; Zhiguo Yuan

2006-01-01

104

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

PubMed Central

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)

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

1992-01-01

105

Energy recovery from municipal solid waste in an anaerobic reactor.  

PubMed

Anaerobic digestion of municipal solid waste was carried out in the laboratory at room temperature to assess the bio-energy production from municipal solid waste (MSW) with high total solids content. The total biogas production from the municipal garbage was found to be 3.2 L in 120 days. The results from the biomethanation process showed that an increase in gas production was observed with increase in digestion period when the bioconversion parameters were found to be favorable for the production of gas. Changes in the parameters, such as pH, affected the production of gas significantly. Samples taken from the reactor at definite interval of time during the degradation process showed considerable reduction in total volatile solids, total carbon, total nitrogen and COD, etc. indicating the waste stabilization. PMID:19552079

Jeyapriya, S P; Saseetharan, M K

2008-07-01

106

Fnr (EtrA) acts as a fine-tuning regulator of anaerobic metabolism in Shewanella oneidensis MR-1  

SciTech Connect

EtrA in Shewanella oneidensis MR-1, a model organism for study of adaptation to varied redox niches, shares 73.6% and 50.8% amino acid sequence identity with the oxygen-sensing regulators Fnr in E. coli and Anr in Pseudomonas aeruginosa, respectively; however, its regulatory role of anaerobic metabolism in Shewanella spp. is not well understood. The expression of the nap genes, nrfA, cymA and hcp was significantly reduced in etrA deletion mutant EtrA7-1; however, limited anaerobic growth and nitrate reduction occurred, suggesting that multiple regulators control nitrate reduction in this strain. Dimethyl sulfoxide (DMSO) and fumarate reductase gene expression was down regulated at least 2-fold and the EtrA7-1 mutant grew poorly with fumarate and dimethyl sulfoxide (DMSO), suggesting both respiratory pathways are under EtrA control. Transcript analysis further suggested a role of EtrA in prophage activation and down regulation of genes implicated in aerobic metabolism. In contrast to previous studies that attributed a minor regulatory role to EtrA in Shewanella spp., this study demonstrates that EtrA acts as a global transcriptional regulator and confers physiological advantages to strain MR-1 under certain growth conditions. In conjunction with other regulators, EtrA fine-tunes the expression of genes involved in anaerobic metabolism in S. oneidensis strain MR-1.

Cruz-Garza, Claribel; Murray, Alison E.; Rodrigues, Jorge L.M.; Gralnick, Jeffrey A.; McCue, Lee Ann; Romine, Margaret F.; Loffler, F. E.; Tiedje, James M.

2011-03-30

107

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

PubMed Central

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.

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

2012-01-01

108

Aerobic and Anaerobic Energy During Resistance Exercise at 80% 1RM  

PubMed Central

The present study investigated the accumulated oxygen deficit (AOD) method to assess the energy cost in resistance exercises (RE). The aim of the study was to evaluate the aerobic and anaerobic energy release during resistance exercises performed at 80% 1-RM in four exercises (half squat, bench press, triceps extension and lat pull down), as well as the accuracy of its estimation. The sample comprised 14 men (age = 26.6 ± 4.9 years; height = 177.7 ± 0.1 cm; body mass = 79.0 ± 11.1 kg; and estimated fat mass = 10.5 ± 4.6%). Test and re-test of 1-RM were applied to every exercise. Low-intensity bouts at 12, 16, 20, and 24% of 1-RM were conducted. Energy cost was then extrapolated to 80% 1-RM exhaustive bout and relative energy contribution were assessed. By utilizing the AOD method, the results of the present study suggest a great proportion of anaerobic metabolism during exercise at 80% 1-RM in the four RE that were analyzed: Bench press = 77,66±6,95%; Half squat = 87,44±6,45%; Triceps extension = 63,91±9,22%; Lat pull down = 71,99±13,73 %. The results of the present study suggest that AOD during resistance exercises presents a pattern that does not match the reports in the literature for other types of exercise. The accuracy of the total energy demand estimation at 80% 1-RM was acceptable in the Bench press, in the Triceps extension and in the Lat pull down, but no in the Half squat. More studies are warranted to investigate the validity of this method in resistance exercise.

Vianna, Jefferson M.; Lima, Jorge P.; Saavedra, Francisco J.; Reis, Victor M.

2011-01-01

109

Modelling the population dynamics and metabolic diversity of organisms relevant in anaerobic/anoxic/aerobic enhanced biological phosphorus removal processes.  

PubMed

In this study, enhanced biological phosphorus removal (EBPR) metabolic models are expanded in order to incorporate the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) under sequential anaerobic/anoxic/aerobic conditions, which are representative of most full-scale EBPR plants. Since PAOs and GAOs display different denitrification tendencies, which is dependent on the phylogenetic identity of the organism, the model was separated into six distinct biomass groups, constituting Accumulibacter Types I and II, as well as denitrifying and non-denitrifying Competibacter and Defluviicoccus GAOs. Denitrification was modelled as a multi-step process, with nitrate (NO(3)), nitrite (NO(2)), nitrous oxide (N(2)O) and di-nitrogen gas (N(2)) being the primary components. The model was calibrated and validated using literature data from enriched cultures of PAOs and GAOs, obtaining a good description of the observed biochemical transformations. A strong correlation was observed between Accumulibacter Types I and II, and nitrate-reducing and non-nitrate-reducing PAOs, respectively, where the abundance of each PAO subgroup was well predicted by the model during an acclimatization period from anaerobic-aerobic to anaerobic-anoxic conditions. Interestingly, a strong interdependency was observed between the anaerobic, anoxic and aerobic kinetic parameters of PAOs and GAOs. This could be exploited when metabolic models are calibrated, since all of these parameters should be changed by an identical factor from their default value. Factors that influence these kinetic parameters include the fraction of active biomass, relative aerobic/anoxic fraction and the ratio of acetyl-CoA to propionyl-CoA. Employing a metabolic approach was found to be advantageous in describing the performance and population dynamics in such complex microbial ecosystems. PMID:20580055

Oehmen, A; Lopez-Vazquez, C M; Carvalho, G; Reis, M A M; van Loosdrecht, M C M

2010-06-12

110

Re-examination of metabolic fluxes in Escherichia coli during anaerobic fermentation of glucose using 13 C labeling experiments and 2-dimensional nuclear magnetic resonance (NMR) spectroscopy  

Microsoft Academic Search

Improved design of metabolic flux estimation using mixed label 13C labeling experiments and identifiability analysis motivated re-examination of metabolic fluxes during anaerobic fermentation\\u000a in the Escherichia coli. Comprehensive metabolic flux maps were determined by using a mixture of differently labeled glucose and compared to conventional\\u000a flux maps obtained using extracellular measurements and comprehensive metabolic flux maps obtained using only U-13C

Madhuresh K. Choudhary; Jong Moon Yoon; Ramon Gonzalez; Jacqueline V. Shanks

2011-01-01

111

Anaerobic Metabolism of Catechol by the Denitrifying Bacterium Thauera aromatica--a Result of Promiscuous Enzymes and Regulators??  

PubMed Central

The anaerobic metabolism of catechol (1,2-dihydroxybenzene) was studied in the betaproteobacterium Thauera aromatica that was grown with CO2 as a cosubstrate and nitrate as an electron acceptor. Based on different lines of evidence and on our knowledge of enzymes and genes involved in the anaerobic metabolism of other aromatic substrates, the following pathway is proposed. Catechol is converted to catechylphosphate by phenylphosphate synthase, which is followed by carboxylation by phenylphosphate carboxylase at the para position to the phosphorylated phenolic hydroxyl group. The product, protocatechuate (3,4-dihydroxybenzoate), is converted to its coenzyme A (CoA) thioester by 3-hydroxybenzoate-CoA ligase. Protocatechuyl-CoA is reductively dehydroxylated to 3-hydroxybenzoyl-CoA, possibly by 4-hydroxybenzoyl-CoA reductase. 3-Hydroxybenzoyl-CoA is further metabolized by reduction of the aromatic ring catalyzed by an ATP-driven benzoyl-CoA reductase. Hence, the promiscuity of several enzymes and regulatory proteins may be sufficient to create the catechol pathway that is made up of elements of phenol, 3-hydroxybenzoate, 4-hydroxybenzoate, and benzoate metabolism.

Ding, Bin; Schmeling, Sirko; Fuchs, Georg

2008-01-01

112

Metabolic and energetic aspects of the growth of Klebsiella aerogenes NCTC 418 on glucose in anaerobic chemostat culture  

Microsoft Academic Search

Klebsiella aerogenes NCTC 418 was cultured anaerobically in chemostat cultures (pH 6.8; 35° C) under carbon, phosphate-, ammonia-, sulphate- and potassium-limited conditions with glucose as the sole carbon- and energy source. The rates of uptake of glucose and excretion of fermentation products were quantitatively determined and carbon, hydrogen- and oxygen balances were constructed with recoveries better than 90%.

M. J. Teixeira de Mattos; D. W. Tempest

1983-01-01

113

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

PubMed Central

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.

Schuhle, Karola; Fuchs, Georg

2004-01-01

114

Energy Conservation and Methane Production in Municipal Wastewater Treatment Using Fixed-Film, Anaerobic Bioreactors.  

National Technical Information Service (NTIS)

An anaerobic, upflow (ANFLOW) bioreactor, which uses fixed films of bacteria in a packed-bed column, is being developed as an energy-conserving wastewater treatment process. Development efforts have progressed through a successful two-year feasibility stu...

R. K. Genung C. W. Hancher A. L. Rivera M. T. Harris

1982-01-01

115

Metabolic influences of fiber size in aerobic and anaerobic locomotor muscles of the blue crab, Callinectes sapidus.  

PubMed

Diameters of some white locomotor muscle fibers in the adult blue crab, Callinectes sapidus, exceed 500 microm whereas juvenile white fibers are <100 microm. It was hypothesized that aerobically dependent processes, such as metabolic recovery following burst contractions, will be significantly impeded in the large white fibers. In addition, dark aerobic fibers of adults, which rely on aerobic metabolism for both contraction and recovery, grow as large as the white fibers. These large aerobic fibers are subdivided, however, thus decreasing the effective diameter of each metabolic functional unit and enabling aerobic contraction. The two goals of this study were: (1) to characterize the development of subdivisions in the dark levator muscle fibers and (2) to monitor post-contractile metabolism as a function of fiber size in aerobic and anaerobic levator muscles. Dark levator muscle fibers from crabs ranging from <0.1 g to >190 g were examined with transmission electron microscopy to determine the density of mitochondria and subdivision diameters. Across all size classes, there was a constant mitochondrial fractional area (25% of the total subdivision area) and subdivision size (mean diameter of 36.5+/-2.7 microm). Thus, blue crab dark levator fibers are unusual in having metabolic functional units (subdivisions) that do not increase in size during development while the contractile functional units (fibers) grow hypertrophically. The body mass scaling of post-contractile lactate dynamics was monitored during recovery from anaerobic, burst exercise in white and dark muscle, and in hemolymph. There were no differences among size classes in lactate accumulation during exercise in either muscle. However, in white fibers from large crabs, lactate continued to increase after exercise, and lactate removal from tissues required a much longer period of time relative to smaller crabs. Differences in lactate removal among size classes were less pronounced in dark fibers, and post-contractile lactate accumulation was significantly higher in white than in dark fibers from large animals. These data suggest that the large white fibers invoke anaerobic metabolism following contraction to accelerate certain phases of metabolic recovery that otherwise would be overly slow. This implies that, in addition to the typical mass-specific decrease in oxidative capacity that accompanies increases in animal mass, aerobic metabolic processes become increasingly limited by surface area to volume and intracellular diffusion constraints in developing white muscle fibers. PMID:15498950

Johnson, L K; Dillaman, R M; Gay, D M; Blum, J E; Kinsey, S T

2004-11-01

116

A new intra-aerobic metabolism in the nitrite-dependent anaerobic methane-oxidizing bacterium Candidatus 'Methylomirabilis oxyfera'.  

PubMed

Biological methane oxidation proceeds either through aerobic or anaerobic pathways. The newly discovered bacterium Candidatus 'Methylomirabilis oxyfera' challenges this dichotomy. This bacterium performs anaerobic methane oxidation coupled to denitrification, but does so in a peculiar way. Instead of scavenging oxygen from the environment, like the aerobic methanotrophs, or driving methane oxidation by reverse methanogenesis, like the methanogenic archaea in sulfate-reducing systems, it produces its own supply of oxygen by metabolizing nitrite via nitric oxide into oxygen and dinitrogen gas. The intracellularly produced oxygen is then used for the oxidation of methane by the classical aerobic methane oxidation pathway involving methane mono-oxygenase. The present mini-review summarizes the current knowledge about this process and the micro-organism responsible for it. PMID:21265781

Wu, Ming L; Ettwig, Katharina F; Jetten, Mike S M; Strous, Marc; Keltjens, Jan T; van Niftrik, Laura

2011-01-01

117

One-carbon metabolism in anaerobic bacteria: organic acid and methane production. Progress report, August 1980-May 1981  

SciTech Connect

The major goal of the project is to understand the basic physiology and biochemistry of one carbon metabolism in anaerobic bacteria that produce organic acids or methane. The aim is to identify key rate, yield and regulatory features of their metabolism and to relate this knowledge to the improvement or development of technology for the bioconversion of organic pyrolysis products (i.e., H/sub 2/, CO, CO/sub 2/ or methanol) to organic acids or natural gas. The studies are comparing the metabolism of two model organisms, Methanosarcina barkeri and Butyribacterium methylotrophicum, both of which grow on the same one carbon compounds but form either methane or acetic-butyric acids as end products.

Zeikus, J.G.

1981-01-01

118

Flexibility in Anaerobic Metabolism as Revealed in a Mutant of Chlamydomonas reinhardtii Lacking Hydrogenase Activity*S?  

PubMed Central

The green alga Chlamydomonas reinhardtii has a network of fermentation pathways that become active when cells acclimate to anoxia. Hydrogenase activity is an important component of this metabolism, and we have compared metabolic and regulatory responses that accompany anaerobiosis in wild-type C. reinhardtii cells and a null mutant strain for the HYDEF gene (hydEF-1 mutant), which encodes an [FeFe] hydrogenase maturation protein. This mutant has no hydrogenase activity and exhibits elevated accumulation of succinate and diminished production of CO2 relative to the parental strain during dark, anaerobic metabolism. In the absence of hydrogenase activity, increased succinate accumulation suggests that the cells activate alternative pathways for pyruvate metabolism, which contribute to NAD(P)H reoxidation, and continued glycolysis and fermentation in the absence of O2. Fermentative succinate production potentially proceeds via the formation of malate, and increases in the abundance of mRNAs encoding two malateforming enzymes, pyruvate carboxylase and malic enzyme, are observed in the mutant relative to the parental strain following transfer of cells from oxic to anoxic conditions. Although C. reinhardtii has a single gene encoding pyruvate carboxylase, it has six genes encoding putative malic enzymes. Only one of the malic enzyme genes, MME4, shows a dramatic increase in expression (mRNA abundance) in the hydEF-1 mutant during anaerobiosis. Furthermore, there are marked increases in transcripts encoding fumarase and fumarate reductase, enzymes putatively required to convert malate to succinate. These results illustrate the marked metabolic flexibility of C. reinhardtii and contribute to the development of an informed model of anaerobic metabolism in this and potentially other algae.

Dubini, Alexandra; Mus, Florence; Seibert, Michael; Grossman, Arthur R.; Posewitz, Matthew C.

2009-01-01

119

Decarboxylating and Nondecarboxylating Glutaryl-Coenzyme A Dehydrogenases in the Aromatic Metabolism of Obligately Anaerobic Bacteria  

Microsoft Academic Search

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 CO2. In this work, we studied GDHs from the strictly anaerobic, aromatic compound-degrading organisms Geobacter metallireducens (GDHGeo) (Fe(III) reducing) and Desulfococcus multivorans (GDHDes) (sulfate reducing). GDHGeo was purified from cells grown on benzoate and

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

2009-01-01

120

Ibogaine affects brain energy metabolism.  

PubMed

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

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

2006-09-16

121

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

PubMed

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

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

2013-01-25

122

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

PubMed Central

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.

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

2013-01-01

123

Anaerobic processes  

Microsoft Academic Search

A major review of the status of research and technology of anaerobic processes to convert wastes and biomass to energy. Among the topics covered are: the microbiology of cellulose hydrolysis and ethanol production, acidogenesis and methanogenesis; process characterization; process optimization; and process application. A summary of selected operation and performance data from anaerobic digestion studies is presented. (Refs. 79).

K. F. Fannin; J. R. Conrad; D. E. Jerger; V. Srivastava; S. Ghosh; D. P. Chynoweth

1981-01-01

124

Metabolic crosstalk between choline/1-carbon metabolism and energy homeostasis.  

PubMed

There are multiple identified mechanisms involved in energy metabolism, insulin resistance and adiposity, but there are here-to-fore unsuspected metabolic factors that also influence these processes. Studies in animal models suggest important links between choline/1-carbon metabolism and energy homeostasis. Rodents fed choline deficient diets become hypermetabolic. Mice with deletions in one of several different genes of choline metabolism have phenotypes that include increased metabolic rate, decreased body fat/lean mass ratio, increased insulin sensitivity, decreased ATP production by mitochondria, or decreased weight gain on a high fat diet. In addition, farmers have recognized that the addition of a metabolite of choline (betaine) to cattle and swine feed reduces body fat/lean mass ratio. Choline dietary intake in humans varies over a > three-fold range, and genetic variation exists that modifies individual requirements for this nutrient. Although there are some epidemiologic studies in humans suggesting a link between choline/1-carbon metabolism and energy metabolism, there have been no controlled studies in humans that were specifically designed to examine this relationship. PMID:23072856

Zeisel, Steven H

2013-03-01

125

Involvement of cytochrome c CymA in the anaerobic metabolism of RDX by Shewanella oneidensis MR-1.  

PubMed

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a cyclic nitramine explosive commonly used for military applications that is responsible for severe soil and groundwater contamination. In this study, Shewanella oneidensis MR-1 was shown to efficiently degrade RDX anaerobically (3.5 µmol·h(-1)·(g protein)(-1)) via two initial routes: (1) sequential N-NO(2) reductions to the corresponding nitroso (N-NO) derivatives (94% of initial RDX degradation) and (2) denitration followed by ring cleavage. To identify genes involved in the anaerobic metabolism of RDX, a library of ~2500 mutants of MR-1 was constructed by random transposon mutagenesis and screened for mutants with a reduced ability to degrade RDX compared with the wild type. An RDX-defective mutant (C9) was isolated that had the transposon inserted in the c-type cytochrome gene cymA. C9 transformed RDX at ~10% of the wild-type rate, with degradation occurring mostly via early ring cleavage caused by initial denitration leading to the formation of methylenedinitramine, 4-nitro-2,4-diazabutanal, formaldehyde, nitrous oxide, and ammonia. Genetic complementation of mutant C9 restored the wild-type phenotype, providing evidence that electron transport components have a role in the anaerobic reduction of RDX by MR-1. PMID:22260206

Perreault, Nancy N; Crocker, Fiona H; Indest, Karl J; Hawari, Jalal

2012-01-19

126

Bioenergetic Conditions of Butyrate Metabolism by a Syntrophic, Anaerobic Bacterium in Coculture with Hydrogen-Oxidizing Methanogenic and Sulfidogenic Bacteria †  

PubMed Central

The butyrate-oxidizing, proton-reducing, obligately anaerobic bacterium NSF-2 was grown in batch cocultures with either the hydrogen-oxidizing bacterium Methanospirillum hungatei PM-1 or Desulfovibrio sp. strain PS-1. Metabolism of butyrate occurred in two phases. The first phase exhibited exponential growth kinetics (phase a) and had a doubling time of 10 h. This value was independent of whether NSF-2 was cultured with a methanogen or a sulfate reducer and likely represents the maximum specific growth rate of NSF-2. This exponential growth phase was followed by a second phase with a nearly constant rate of degradation (phase b) which dominated the time course of butyrate degradation. The specific activity of H2 uptake by the hydrogen-oxidizing bacterium controlled the bioenergetic conditions of metabolism in phase b. During this phase both the Gibbs free energy (?G?) and the butyrate degradation rate (v) were greater for NSF-2-Desulfovibrio sp. strain PS-1 (?G? = ?17.0 kJ/mol; v = 0.20 mM/h) than for NSF-2-M. hungatei PM-1 (?G? = ?3.8 kJ/mol, v = 0.12 mM/h). The ?G? value remained stable and characteristic of the two hydrogen oxidizers during phase b. The stable ?G? resulted from the close coupling of the rates of butyrate and H2 oxidation. The addition of 2-bromoethanesulfonate to a NSF-2-methanogen coculture resulted in the total inhibition of butyrate degradation; the inhibition was relieved when Desulfovibrio sp. strain PS-1 was added as a new H2 sink. When the specific activity of H2 consumption was increased by adding higher densities of the Desulfovibrio sp. to 2-bromoethanesulfonate-inhibited NSF-2-methanogen cocultures, lower H2 pool sizes and higher rates of butyrate degradation resulted. Thus, it is the kinetic parameters of H2 consumption, not the type of H2 consumer per se, that establishes the thermodynamic conditions which in turn control the rate of fatty acid degradation. The bioenergetic homeostasis we observed in phase b was a result of the kinetics of the coculture members and the feedback inhibition by hydrogen which prevents butyrate degradation rates from reaching their theoretical Vmax.

Dwyer, Daryl F.; Weeg-Aerssens, Els; Shelton, Daniel R.; Tiedje, James M.

1988-01-01

127

Anaerobic microbial biogeochemistry in a northern bog: Acetate as a dominant metabolic end product  

NASA Astrophysics Data System (ADS)

Field measurements and incubation techniques were used to determine the dynamics of acetate formation, iron reduction, and methanogenesis in surficial peat of an Alaskan bog. Acetate concentrations were ˜100 ?M early in the season and decreased to ˜20 ?M in July when the water table decreased. Acetate levels increased rapidly to ˜1000 ?M when the water table rose to the surface in August. Acetate production in anaerobic slurries occurred at rates of 2.8-420 nmol carbon mL-1 day-1, which was 7-120 times more rapid than CH4 production. Experiments utilizing 14C-acetate confirmed that methanogenesis was not acetoclastic although acetate was converted very slowly to CO2. Peat incubated anaerobically for 4.5 months at 24°C never produced methane from acetate, suggesting that anaerobic acetate accumulation would have occurred all season if the water table had remained high. CO2 production was the most rapid process measured in laboratory incubations (up to 750 nmol mL-1 day-1) and appeared to be due primarily to fermentation. Acetate was the primary organic terminal product of anaerobic decomposition in the bog, and acetate was ultimately oxidized to CO2 via aerobic respiration and to a much lesser extent anaerobically by Fe reduction.

Duddleston, Khrystyne N.; Kinney, Monica A.; Kiene, Ronald P.; Hines, Mark E.

2002-12-01

128

Toward Homosuccinate Fermentation: Metabolic Engineering of Corynebacterium glutamicum for Anaerobic Production of Succinate from Glucose and Formate  

PubMed Central

Previous studies have demonstrated the capability of Corynebacterium glutamicum for anaerobic succinate production from glucose under nongrowing conditions. In this work, we have addressed two shortfalls of this process, the formation of significant amounts of by-products and the limitation of the yield by the redox balance. To eliminate acetate formation, a derivative of the type strain ATCC 13032 (strain BOL-1), which lacked all known pathways for acetate and lactate synthesis (?cat ?pqo ?pta-ackA ?ldhA), was constructed. Chromosomal integration of the pyruvate carboxylase gene pycP458S into BOL-1 resulted in strain BOL-2, which catalyzed fast succinate production from glucose with a yield of 1 mol/mol and showed only little acetate formation. In order to provide additional reducing equivalents derived from the cosubstrate formate, the fdh gene from Mycobacterium vaccae, coding for an NAD+-coupled formate dehydrogenase (FDH), was chromosomally integrated into BOL-2, leading to strain BOL-3. In an anaerobic batch process with strain BOL-3, a 20% higher succinate yield from glucose was obtained in the presence of formate. A temporary metabolic blockage of strain BOL-3 was prevented by plasmid-borne overexpression of the glyceraldehyde 3-phosphate dehydrogenase gene gapA. In an anaerobic fed-batch process with glucose and formate, strain BOL-3/pAN6-gap accumulated 1,134 mM succinate in 53 h with an average succinate production rate of 1.59 mmol per g cells (dry weight) (cdw) per h. The succinate yield of 1.67 mol/mol glucose is one of the highest currently described for anaerobic succinate producers and was accompanied by a very low level of by-products (0.10 mol/mol glucose).

Litsanov, Boris; Brocker, Melanie

2012-01-01

129

The electron transport chain in anaerobically functioning eukaryotes  

Microsoft Academic Search

Many lower eukaryotes can survive anaerobic conditions via a fermentation pathway that involves the use of the reduction of endogenously produced fumarate as electron sink. This fumarate reduction is linked to electron transport in an especially adapted, anaerobically functioning electron-transport chain.An aerobic energy metabolism with Krebs cycle activity is accompanied by electron transfer from succinate to ubiquinone via complex II

Aloysius G. M. Tielens; Jaap J. Van Hellemond

1998-01-01

130

Vampires, Pasteur and reactive oxygen species. Is the switch from aerobic to anaerobic metabolism a preventive antioxidant defence in blood-feeding parasites?  

PubMed

Several species of parasites show a reduction of their respiratory activity along their developmental cycles after they start to feed on vertebrate blood, relying on anaerobic degradation of carbohydrates to achieve their energy requirements. Usually, these parasites choose not to breathe despite of living in an environment of high oxygen availability such as vertebrate blood. Absence of the 'Pasteur effect' in most of these parasites has been well documented. Interestingly, together with the switch from aerobic to anaerobic metabolism in these parasites, there is clear evidence pointing to an increase in their antioxidant defences. As the respiratory chain in mitochondria is a major site of production of reactive oxygen species (ROS), we propose here that the arrest of respiration constitutes an adaptation to avoid the toxic effects of ROS. This situation would be especially critical for blood-feeding parasites because ROS produced in mitochondria would interact with pro-oxidant products of blood digestion, such as haem and/or iron, and increase the oxidative damage to the parasite's cells. PMID:12163151

Oliveira, Pedro L; Oliveira, Marcus F

2002-08-14

131

Role of antioxidant and anaerobic metabolism enzymes in providing tolerance to maize (Zea mays L.) seedlings against waterlogging.  

PubMed

The present investigation was undertaken to identify the possible mode of mechanism that could provide tolerance to maize (Zea mays L.) seedlings under waterlogging. Using cup method, a number of maize genotypes were screened on the basis of survival of the seedlings kept under waterlogging. Two tolerant (LM5 and Parkash) and three susceptible (PMH2, JH3459 and LM14) genotypes were selected for the present study. Activities of antioxidant and ethanolic fermentation enzymes and content of hydrogen peroxide (H2O2), glutathione and ascorbic acid were determined in roots of these genotypes after 72 h of waterlogging. Waterlogging treatment caused decline in activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in all the genotypes. However, only susceptible genotypes showed slight increase in glutathione reductase (GR) activity. Significant reduction in APX/GR ratio in susceptible genotypes might be the cause of their susceptibility to waterlogging. The tolerant seedlings had higher GR activity than susceptible genotypes under unstressed conditions. Stress led to decrease in H202 and increase in glutathione content of both tolerant and susceptible genotypes, but only tolerant genotypes exhibited increase in ascorbic acid under waterlogging conditions. In the tolerant genotypes, all the enzymes of anaerobic metabolism viz. alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and pyruvate decarboxylase (PDC) were upregulated under waterlogging, whereas in susceptible genotypes, only ADH was upregulated, suggesting that efficient upregulation of entire anaerobic metabolic machinery is essential for providing tolerance against waterlogging. The study provides a possible mechanism for waterlogging tolerance in maize. PMID:22165294

Chugh, Vishal; Kaur, Narinder; Gupta, Anil K

2011-10-01

132

Overflow metabolism during anaerobic growth of Klebsiella aerogenes NCTC 418 on glycerol and dihydroxyacetone in chemostat culture  

Microsoft Academic Search

Klebsiella aerogenes NCTC 418 was grown anaerobically in chemostat culture with glycerol as source of carbon and energy. Glycerol-limited cultures did not ferment the carbon source with maximal efficiency but produced considerable amounts of 1,3-propanediol. The fraction of glycerol converted to this product depended on the growth rate and on the limitation: faster growing cells produced relatively more of this

H. Streekstra; M. J. Teixeira de Mattos; O. M. Neijssel; D. W. Tempest

1987-01-01

133

Proteomic investigation of glucose metabolism in the butyrate-producing gut anaerobe Fusobacterium varium.  

PubMed

A proteome survey and MS analysis were conducted to investigate glucose metabolism in Fusobacterium varium, a butyrate-producing constituent of the indigenous human gut microflora. The bacterium was capable of catabolizing glucose as the main energy source via the Embden-Meyerhof-Parnas pathway. 2-DE analyses revealed that the apparent concentrations of the six identified glycolytic enzymes (pyruvate kinase, enolase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase, and glyceraldehyde-3-phosphate dehydrogenase) were specifically increased in response to the presence of glucose in the chemically defined minimal growth medium, and did not diminish when the medium was additionally supplemented with L-glutamate, an amino acid readily fermented by members of the Fusobacterium genus. A substrate pool depletion study revealed that the sugar, and not the amino acid, is the more efficient growth substrate. Both proteomics and substrate pool depletion studies revealed that F. varium can simultaneously utilize both glucose and L-glutamate as energy sources. Enzymes involved in L-glutamate metabolism were also identified, including an NAD-dependent glutamate dehydrogenase and two enzymes of the methylaspartate pathway of L-glutamate catabolism (glutamate mutase and methylaspartate ammonia-lyase). Their apparent intracellular concentrations were elevated when the bacterium was cultured in media supplemented with excess L-glutamate. Our observation that the apparent concentrations of specific proteins were elevated in response to a particular growth substrate supplied as an energy source provides the first evidence for the presence of a nutrient-responsive mechanism governing intracellular protein concentration in F. varium. PMID:17464938

Potrykus, Joanna; Mahaney, Brandi; White, Robert L; Bearne, Stephen L

2007-06-01

134

Pharmacological preconditioning with diazoxide slows energy metabolism during sustained ischemia  

PubMed Central

Ischemic preconditioning (PC) is associated with slower destruction of the adenine nucleotide pool (?Ad) and slower rate of anaerobic glycolysis during ischemic stress. These changes are concordant with the preconditioned state, supporting an essential role of lowered energy demand in the cardioprotective mechanism of PC. Although pharmacological PC induced by the activation of mitochondrial KATP channels also limits infarct size, its effect on energy metabolism during sustained ischemia is unknown. Using metabolite levels found at baseline and after a 15 min test episode of regional ischemia, the effect of a cardioprotective dose of diazoxide on metabolic features associated with PC was tested in barbital-anesthetized, open-chest dogs. Diazoxide (3.5 mg/kg at an intravenous rate of 1 mL/min) infused before a test episode of ischemia had no effect on baseline metabolic indices. However, during ischemic stress, treated hearts exhibited less destruction of ATP, less degradation of the ?Ad into nucleosides and bases, as well as less lactate production than control hearts subjected only to ischemic stress. Thus, diazoxide mimics the metabolic alterations observed in PC tissue. This supports the hypothesis that a reduction in energy demand, which is now equated with an increased ATP to ADP ratio in the sarcoplasm, is a critical component of the mechanism of cardioprotection in preconditioned myocardium. It is hypothesized that during PC or diazoxide treatment, the passage of the ?Ad into and out of the mitochondria is slowed, limiting the level of ATP available to the mitochondrial ATPase and preserving ATP and the total ?Ad. Altered ischemic mitochondrial metabolism plays an important role in establishing and maintaining the preconditioned state.

Schwartz, Lisa M; Reimer, Keith A; Crago, Mark S; Jennings, Robert B

2007-01-01

135

Characterization of follicular energy metabolism.  

PubMed

It has been shown that mouse ovarian follicles have a large glycolytic capacity, and this study was undertaken to determine whether follicles can develop normally using glycolysis alone. Pre-antral mouse follicles were grown using an in-vitro system which supports development to the preovulatory stage within 5 days. Cultures were maintained in either aerobic conditions in the presence of the inhibitor of oxidative phosphorylation, sodium malonate, or under anaerobic conditions. Samples of media were removed every 24 h and analysed for oestradiol using an enzyme-linked immunosorbent assay (ELISA) technique and for lactate and glucose using a fluorometric assay. Follicle size, oestradiol production and glycolytic rate were not significantly different between control and sodium malonate-treated follicles. Follicles cultured under anaerobic conditions showed significantly slower rates of growth and oestradiol production compared with controls. However, the rate of glycolysis was significantly higher during anoxia. Results indicated that anaerobic glycolysis may sustain limited periods of growth during the pre-antral phase, but that the presence of oxygen is vital to ensure normal development. It is concluded that pre-antral follicles can undergo development to the preovulatory stage using glycolysis alone, a feature which may allow them to conserve their limited supply of oxygen for other vital biosynthetic processes. PMID:8046010

Boland, N I; Humpherson, P G; Leese, H J; Gosden, R G

1994-04-01

136

Energy and nutrient recovery from anaerobic treatment of organic wastes  

NASA Astrophysics Data System (ADS)

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.

Henrich, Christian-Dominik

137

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

PubMed

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

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

2013-04-06

138

Pyruvate Oxidoreductases Involved in Glycolytic Anaerobic Metabolism of Polychaetes from the Continental Shelf off Central-South Chile  

NASA Astrophysics Data System (ADS)

The presence of low oxygen conditions in extensive areas of the continental shelf off central-south Chile has important effects on the biochemical adaptations of the organisms living in this ecosystem. Polychaetes assemblages cohabit on the shelf with an extensively distributed prokaryotic community made up of giant filamentous sulfur bacteria (mainly Thioploca sp.). The aim of this research was to characterize the pyruvate oxidoreductases enzymes involved in the biochemical adaptation of these benthic polychaetes. Nine polychaete species ( Paraprionospio pinnata, Nephtys ferruginea, Glycera americana, Haploscoloplos sp., Lumbrineris composita, Sigambra bassi, Aricidea pigmentata , Cossura chilensis, and Pectinaria chilensis) were assayed for lactic dehydrogenase (LDH), octopine dehydrogenase (OPDH), strombine dehydrogenase (STRDH) and alanopine dehydrogenase (ALPDH). Each species had a characteristic number of the pyruvate oxidoreductases assayed ranging from 4 in Paraprionospio pinnata to 1 in Pectinaria chilensis . The pyruvate saturation curves obtained for the enzymes from all species analysed, except L. composita, suggest that NADH can be oxidized at different rates depending on the amino acid used in the reaction with pyruvate. Our results indicate that organisms having more that one pyruvate oxidoreductase present a greater metabolic capacity to cope with functional and environmental hypoxia because these enzymes would better regulate the pyruvate consumption rate during the transition period. Thus, the dominance of Paraprionospio pinnata in the study area and its worldwide distribution is consistent with its higher number of pyruvate oxidoreductases with different pyruvate consumption rates involved in anaerobic metabolism. Finally, a positive allometric relationship was found between body size and the specific activity of ALPDH, STRDH, and maximum pyruvate oxidoreductase specific activity. This latter result suggests a positive scaling of the specific anaerobic metabolism in polychaetes.

González, R. R.; Quiñones, R. A.

2000-10-01

139

Pollution and energy management through the anaerobic approach  

SciTech Connect

Describes how a rum producer on Puerto Rico is using an anaerobic reactor to convert distillery wastes to methane gas. Reports that the reactor generates enough methane to replace 75 barrels of fuel oil per day while reducing the biochemical oxygen demand (BOD) load. Explains that the reactor is loaded with microbial seed, water and mosto at a rate of 50,000 gpd. Plant operations, requiring minimal personnel, involve maintenance of correct environment for anaerobic microorganisms through periodic adjustment of pH and temperature. Points out that many modifications are possible, and thus the Bacardi process is applicable to still-bottom wastes, spent grain liquors, centrates, pulp and paper wastes, sweet or acid cheese whey, food packing and meat packing wastes, liquid extraction raffinates, sludge heat treatment sidestreams, corn products wastes, protein extraction wastes, and winery wastes.

Szendrey, L.M.; Dorion, G.H.; Schafer, P.E.

1982-09-01

140

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

PubMed

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

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

2013-02-04

141

Energetics of End Product Excretion in Anaerobic Bacteria and the Metabolism of Fatty Acids by Syntrophomonas Wolfei. Progress Report, January 31-December 15, 1985.  

National Technical Information Service (NTIS)

This work addresses the metabolism of fatty acids and the energetics of growth of the anaerobic, syntrophic, fatty acid-degrading bacterium, Syntrophomonas wolfei. S. wolfei degrades C sub 4 to C sub 8 straight chain fatty acids to acetate and H sub 2 or ...

M. J. McInerney

1985-01-01

142

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

Microsoft Academic Search

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

Thomas D. DiStefano

2009-01-01

143

Anaerobic microbial transformations in subsurface environments  

SciTech Connect

The first draft of a literature review article entitled, ''Metabolism of Homocyclic (Benzenoid) and Heterocyclic Aromatic Compounds by Microorganisms Under Anaerobic Conditions'' is completed. The article covers biodegradation of both heterocyclic and homocyclic aromatic compounds under a variety of conditions including nitrate reducing, fermentation, sulfate reducing, and methanogensis. Laboratory experiments have been designed to study the anaerobic biotransformation processes involving organic substance derived from energy residual wastes. The test compounds selected for the initial anaerobic biodegradation experiments include aniline, indole, and pyridine. A Hungate apparatus is presently in operation.

Bollag, J.M.; Berry, D.F.; Chanmugathas, P.

1985-04-01

144

Anaerobic phototrophic metabolism of 3-chlorobenzoate by Rhodopseudomonas palustris WS17.  

PubMed

A mixed phototrophic culture was found to reductively metabolize 3-chlorobenzoate in the presence of benzoate following adaptation for a period of 7 weeks. The dominant bacterial isolate from this mixed culture, identified as Rhodopseudomonas palustris WS17, metabolized 3-chlorobenzoate completely in the presence of benzoate and light and in the absence of oxygen. [14C]3-chlorobenzoate was converted to 14CO2 and cell 3-chlorobenzoate metabolism is a common phenomenon in this species. PMID:2128012

Kamal, V S; Wyndham, R C

1990-12-01

145

INSECT FAT BODY: ENERGY, METABOLISM, AND REGULATION  

PubMed Central

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.

Arrese, Estela L.; Soulages, Jose L.

2010-01-01

146

Effect of creatine on aerobic and anaerobic metabolism in skeletal muscle in swimmers  

Microsoft Academic Search

OBJECTIVE: To examine the effect of a relatively low dose of creatine on skeletal muscle metabolism and oxygen supply in a group of training athletes. METHODS: 31P magnetic resonance and near-infrared spectroscopy were used to study calf muscle metabolism in a group of 10 female members of a university swimming team. Studies were performed before and after a six week

C H Thompson; G J Kemp; A L Sanderson; R M Dixon; P Styles; D J Taylor; G K Radda

1996-01-01

147

The source of reducing power in the anaerobic metabolism of polyphosphate accumulating organisms (PAOs) - a mini-review.  

PubMed

Glycolysis has been generally accepted to be the source of reducing power used for the synthesis of polyhydroxyalkanoates (PHAs) in the anaerobic metabolism of polyphosphate accumulating organisms (PAOs). However, the tricarboxylic acid cycle (TCA) has also been suggested to contribute to the generation of reducing equivalents, creating some controversy in this research field over the last two decades. Various research approaches have been applied in order to clarify this issue, including the analysis of intracellular compounds, labelled carbon substrates and gene expression. However, the conclusions of these studies seem not to be consolidated. The extent of TCA cycle involvement could be related to the experimental methods employed, the community structure of the cultures used, and also the operational conditions employed. This mini-review analyses the historical findings related to the source of reducing power in PAOs, and highlights the different approaches used in the previous studies. Key factors influencing the generation of reducing power through different metabolic pathways are discussed, and further research directions are also proposed. PMID:20371922

Zhou, Yan; Pijuan, Maite; Oehmen, Adrian; Yuan, Zhiguo

2010-01-01

148

Energy metabolism of fish brain  

Microsoft Academic Search

This review focuses on recent research on the metabolic function of fish brain. Fish brain is isolated from the systemic circulation by a blood–brain barrier that allows the transport of glucose, monocarboxylates and amino acids. The limited information available in fishes suggests that oxidation of exogenous glucose and oxidative phosphorylation provide most of the ATP required for brain function in

José L. Soengas; Manuel Aldegunde

2002-01-01

149

Anaerobic growth of a Rhodopseudomonas species in the dark with carbon monoxide as sole carbon and energy substrate.  

PubMed Central

A species of Rhodopseudomonas that grows under strict anaerobic conditions in the dark and requires CO was isolated from lake and pond sediments. Although anaerobic growth in the dark occurs in a chemically defined mineral medium with CO as the only carbon and energy source, growth is stimulated by adding trypticase. Under these conditions, cells exhibit a generation time of 6.7 hr and reach a final concentration of 1 to 3 X 10(9) cells per ml of liquid medium. Resting suspensions of CO-grown cells metabolize about 6.7 mumol of CO per mg of protein in 1 hr and produce equimolar amounts of CO2 and H2 according to the equation CO + H2O leads to CO2 + H2. As predicted by this equation, when cells were suspended in tritium-labeled water containing potassium phosphate buffer at pH 7.0 and incubated with pure CO, 3H2 gas was produced at linear rate with a constant specific activity.

Uffen, R L

1976-01-01

150

Principles of Human Energy Metabolism  

Microsoft Academic Search

\\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

Jose Galgani; Eric Ravussin

151

Geranic Acid Formation, an Initial Reaction of Anaerobic Monoterpene Metabolism in Denitrifying Alcaligenes defragrans  

PubMed Central

Monoterpenes with an unsaturated hydrocarbon structure are mineralized anaerobically by the denitrifying ?-proteobacterium Alcaligenes defragrans. Organic acids occurring in cells of A. defragrans and culture medium were characterized to identify potential products of the monoterpene activation reaction. Geranic acid (E,E-3,7-dimethyl-2,6-octadienoic acid) accumulated to 0.5 mM in cells grown on ?-phellandrene under nitrate limitation. Cell suspensions of A. defragrans 65Phen synthesized geranic acid in the presence of ?-myrcene, ?-phellandrene, limonene, or ?-pinene. Myrcene yielded the highest transformation rates. The alicyclic acid was consumed by cell suspensions during carbon limitation. Heat-labile substances present in cytosolic extracts catalyzed the formation of geranic acid from myrcene. These results indicated that a novel monoterpene degradation pathway must be present in A. defragrans.

Heyen, Udo; Harder, Jens

2000-01-01

152

Anaerobic biotechnological approaches for production of liquid energy carriers from biomass  

Microsoft Academic Search

In recent years, increasing attention has been paid to the use of renewable biomass for energy production. Anaerobic biotechnological\\u000a approaches for production of liquid energy carriers (ethanol and a mixture of acetone, butanol and ethanol) from biomass can\\u000a be employed to decrease environmental pollution and reduce dependency on fossil fuels. There are two major biological processes\\u000a that can convert biomass

Dimitar Karakashev; Anne Belinda Thomsen; Irini Angelidaki

2007-01-01

153

Recent development of anaerobic digestion processes for energy recovery from wastes.  

PubMed

Anaerobic digestion leads to the overall gasification of organic wastewaters and wastes, and produces methane and carbon dioxide; this gasification contributes to reducing organic matter and recovering energy from organic carbons. Here, we propose three new processes and demonstrate the effectiveness of each process. By using complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment, the chemical oxygen demand (COD) in wastewater was decreased to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge, cow feces, chicken feces, and food waste without the dilution of the ammonia produced by water or carbon-rich wastes. The hydrogen-methane two-stage fermentation (Hy-Met process), in which the hydrogen produced in the first stage is used for a fuel cell system to generate electricity and the methane produced in the second stage is used to generate heat energy to heat the two reactors and satisfy heat requirements, is useful for the treatment of sugar-rich wastewaters, bread wastes, and biodiesel wastewaters. PMID:17368391

Nishio, Naomichi; Nakashimada, Yutaka

2007-02-01

154

The Metabolic Reprogramming Evoked by Nitrosative Stress Triggers the Anaerobic Utilization of Citrate in Pseudomonas fluorescens  

PubMed Central

Nitrosative stress is an ongoing challenge that most organisms have to contend with. When nitric oxide (NO) that may be generated either exogenously or endogenously encounters reactive oxygen species (ROS), it produces a set of toxic moieties referred to as reactive nitrogen species (RNS). As these RNS can severely damage essential biomolecules, numerous organisms have evolved elaborate detoxification strategies to nullify RNS. However, the contribution of cellular metabolism in fending off nitrosative stress is poorly understood. Using a variety of functional proteomic and metabolomic analyses, we have identified how the soil microbe Pseudomonas fluorescens reprogrammed its metabolic networks to survive in an environment enriched by sodium nitroprusside (SNP), a generator of nitrosative stress. To combat the RNS-induced ineffective aconitase (ACN) and tricarboxylic acid (TCA) cycle, the microbe invoked the participation of citrate lyase (CL), phosphoenolpyruvate carboxylase (PEPC) and pyruvate phosphate dikinase (PPDK) to convert citrate, the sole source of carbon into pyruvate and ATP. These enzymes were not evident in the control conditions. This metabolic shift was coupled to the concomitant increase in the activities of such classical RNS detoxifiers as nitrate reductase (NR), nitrite reductase (NIR) and S-nitrosoglutathione reductase (GSNOR). Hence, metabolism may hold the clues to the survival of organisms subjected to nitrosative stress and may provide therapeutic cues against RNS-resistant microbes.

Auger, Christopher; Lemire, Joseph; Cecchini, Dominic; Bignucolo, Adam; Appanna, Vasu D.

2011-01-01

155

Anaerobic metabolism in the roots of seedlings of the invasive exotic Lepidium latifolium  

Microsoft Academic Search

Lepidium latifolium is an invasive exotic crucifer that is widely distributed in riparian zones and wetlands. In this study, anoxic carbohydrate metabolism and post-anoxic injury in the roots of L. latifolium seedlings were examined. A significant increase in the activity of the fermentative enzymes alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) in roots occurred under anoxia and increased with the

Hongjun Chen; Robert G. Qualls

2003-01-01

156

The metabolic reprogramming evoked by nitrosative stress triggers the anaerobic utilization of citrate in Pseudomonas fluorescens.  

PubMed

Nitrosative stress is an ongoing challenge that most organisms have to contend with. When nitric oxide (NO) that may be generated either exogenously or endogenously encounters reactive oxygen species (ROS), it produces a set of toxic moieties referred to as reactive nitrogen species (RNS). As these RNS can severely damage essential biomolecules, numerous organisms have evolved elaborate detoxification strategies to nullify RNS. However, the contribution of cellular metabolism in fending off nitrosative stress is poorly understood. Using a variety of functional proteomic and metabolomic analyses, we have identified how the soil microbe Pseudomonas fluorescens reprogrammed its metabolic networks to survive in an environment enriched by sodium nitroprusside (SNP), a generator of nitrosative stress. To combat the RNS-induced ineffective aconitase (ACN) and tricarboxylic acid (TCA) cycle, the microbe invoked the participation of citrate lyase (CL), phosphoenolpyruvate carboxylase (PEPC) and pyruvate phosphate dikinase (PPDK) to convert citrate, the sole source of carbon into pyruvate and ATP. These enzymes were not evident in the control conditions. This metabolic shift was coupled to the concomitant increase in the activities of such classical RNS detoxifiers as nitrate reductase (NR), nitrite reductase (NIR) and S-nitrosoglutathione reductase (GSNOR). Hence, metabolism may hold the clues to the survival of organisms subjected to nitrosative stress and may provide therapeutic cues against RNS-resistant microbes. PMID:22145048

Auger, Christopher; Lemire, Joseph; Cecchini, Dominic; Bignucolo, Adam; Appanna, Vasu D

2011-12-01

157

Metabolism  

MedlinePLUS

Metabolism refers to all the physical and chemical processes in the body that convert or use energy, ... Elsas LJ II. Approach to inborn errors of metabolism. In: Goldman L, Schafer AI, eds. Cecil Medicine . ...

158

Intermediate Energy Metabolism of Leptospira  

PubMed Central

Metabolic studies were performed on three representative serotypes of Leptospira: a water isolate designated B16 and two pathogenic serotypes, pomona and schueffneri. Examination of whole cells of B16 for their ability to oxidize various substrates revealed that oleate significantly stimulated oxygen uptake. The respiratory quotient of 0.7 implied that oleate was degraded to carbon dioxide and water. Other substrates, such as carbohydrates, alcohols, intermediates of the citric acid cycle, and short-chain acids, including selected amino acids, did not stimulate endogenous respiration of whole cells. No oxygen uptake could be measured when cell-free extracts were tested with the substrates used with whole cells. Enzymatic analyses of cell-free extracts of the three strains demonstrated enzymes of the citric acid cycle, enzymes of the glycolytic and pentose pathways, and the general acyl coenzyme A dehydrogenase required for ?-oxidation of fatty acids. Strain B16 and the two pathogenic serotypes appeared to possess similar metabolic capabilities. Enzymatic data might also explain the apparent inability of B16 to oxidize other substrates; kinases necessary for activation of common nonphosphorylated compounds were not detected in leptospiral extracts. These findings emphasized the dependence of leptospiral growth upon long-chain fatty acids.

Baseman, J. B.; Cox, C. D.

1969-01-01

159

One carbon metabolism in anaerobic bacteria: organic acid and methane production. Final technical report  

SciTech Connect

Organic acids (i.e acetate and butyrate) and methane are respectively important as a chemical commodity and a fuel source for industry. Both of these products can be generated via bacterial fermentation of single carbon compounds (i.e, H/sub 2//CO/sub 2/, HCOOH, CO CH/sub 3/OH) derived from syngas or the pyrolysis of either coals-peats or renewable biomass. This research aims to understand the pathways and regulation of one carbon metabolism in acidogenic and methanogenic bacteria by detailed physiological and biochemical studies. These investigations will characterize and compare formate, methanol, H/sub 2//CO/sub 2/, CO, and acetate metabolism of Methanosarcina barkeri with that of Butyribacterium methylotrophicum. The research will focus on: elucidation of the function of formate dehydrogenase and carbon monoxide dehydrogenase; the catabolic routes and biochemical mechanisms for transformation of single carbon compounds and acetate; and, the regulation of single carbon metabolism during growth on multiple C/sub 1/ substrates or on multicarbon substrates. 8 refs.

Zeikus, J.G.

1985-01-01

160

Effects of Training on Phagocytic and Oxidative Metabolism of Peripheral Neutrophils in Horses Exercised in the Aerobic–Anaerobic Transition Area  

Microsoft Academic Search

Using simple techniques, the neutrophil function, in its phagocytosis and oxidative metabolism stages, was evaluated in horses. This was done before and after moderate exercise at the aerobic–anaerobic threshold (standardized heart rate 150 beats\\/min and lactate level of 3.07±0.21 mmol\\/L). The objective was to determine whether regular training and moderate exercise improved the neutrophil function. A group of 19 horses

B. M. Escribano; F. M. Castejón; R. Vivo; R. Santisteban; E. I. Agüera; M. D. Rubio

2005-01-01

161

Anaerobic metabolism of resorcyclic acids ( m -dihydroxybenzoic acids) and resorcinol (1,3-benzenediol) in a fermenting and in a denitrifying bacterium  

Microsoft Academic Search

The anaerobic metabolism of 2,4- and 2,6-dihydroxybenzoic acid (beta- and gamma-resorcyclic acid) and 1,3-benzenediol (resorcinol) was investigated in a fermenting coculture of a Clostridium sp. with a Campylobacter sp. (Tschech A and Schink B (1985) Arch Microbiol 143: 52–59) and in a newly isolated denitrifying gram-negative bacterium. The enzymes of this pathway were searched for and partly characterized in vitro.

Claudia Kluge; Andreas Tschech; Georg Fuchs

1990-01-01

162

Energetics of end product excretion in anaerobic bacteria and the metabolism of fatty acids by Syntrophomonas wolfei. Progress report, January 31-December 15, 1985  

SciTech Connect

This work addresses the metabolism of fatty acids and the energetics of growth of the anaerobic, syntrophic, fatty acid-degrading bacterium, Syntrophomonas wolfei. S. wolfei degrades C/sub 4/ to C/sub 8/ straight chain fatty acids to acetate and H/sub 2/ or acetate, propionate and H/sub 2/; isoheptanoate is degraded to isovalerate, acetate, and H/sub 2/. S. wolfei can not use any common bacterial energy source that will allow it to grow in pure culture. A significant breakthrough in the cultivation of S. wolfei was achieved. Long term (3 months) incubation of S. wolfei cocultures in medium with crotonate selects for a population of S. wolfei cells that can use this compound. These cultures contain large numbers of S. wolfei cells and very few cells of the methanogen. Pure cultures of S. wolfei do not use butyrate. However, when pure cultures of S. wolfei are incubated in the presence of H/sub 2/-using bacteria, butyrate is degraded to acetate and H/sub 2/. These data show that the cells present in the pure cultures are in fact S. wolfei. Growth of S. wolfei with crotonate is faster and much higher cell densities are obtained. Thus, large amounts of cell material will be available for biochemical studies. 3 refs.

McInerney, M.J.

1985-01-01

163

Isolation, growth, and metabolism of an obligately anaerobic, selenate- respiring bacterium, strain SES-3  

USGS Publications Warehouse

A gram-negative, strictly anaerobic, motile vibrio was isolated from a selenate-respiring enrichment culture. The isolate, designated strain SES-3, grew by coupling the oxidation of lactate to acetate plus CO2 with the concomitant reduction of selenate to selenite or of nitrate to ammonium. No growth was observed on sulfate or selenite, but cell suspensions readily reduced selenite to elemental selenium (Se0). Hence, SES-3 can carry out a complete reduction of selenate to Se0. Washed cell suspensions of selenate- grown cells did not reduce nitrate, and nitrate-grown cells did not reduce selenate, indicating that these reductions are achieved by separate inducible enzyme systems. However, both nitrate-grown and selenate-grown cells have a constitutive ability to reduce selenite or nitrite. The oxidation of [14C]lactate to 14CO2 coupled to the reduction of selenate or nitrate by cell suspensions was inhibited by CCCP (carbonyl cyanide m- chlorophenylhydrazone), cyanide, and azide. High concentrations of selenite (5 mM) were readily reduced to Se0 by selenate-grown cells, but selenite appeared to block the synthesis of pyruvate dehydrogenase. Tracer experiments with [75Se]selenite indicated that cell suspensions could achieve a rapid and quantitative reduction of selenite to Se0. This reduction was totally inhibited by sulfite, partially inhibited by selenate or nitrite, but unaffected by sulfate or nitrate. Cell suspensions could reduce thiosulfate, but not sulfite, to sulfide. These results suggest that reduction of selenite to Se0 may proceed, in part, by some of the components of a dissimilatory system for sulfur oxyanions.

Oremland, R. S.; Blum, J. S.; Culbertson, C. W.; Visscher, P. T.; Miller, L. G.; Dowdle, P.; Strohmaier, F. E.

1994-01-01

164

Isolation, Growth, and Metabolism of an Obligately Anaerobic, Selenate-Respiring Bacterium, Strain SES-3  

PubMed Central

A gram-negative, strictly anaerobic, motile vibrio was isolated from a selenate-respiring enrichment culture. The isolate, designated strain SES-3, grew by coupling the oxidation of lactate to acetate plus CO2 with the concomitant reduction of selenate to selenite or of nitrate to ammonium. No growth was observed on sulfate or selenite, but cell suspensions readily reduced selenite to elemental selenium (Se0). Hence, SES-3 can carry out a complete reduction of selenate to Se0. Washed cell suspensions of selenate-grown cells did not reduce nitrate, and nitrate-grown cells did not reduce selenate, indicating that these reductions are achieved by separate inducible enzyme systems. However, both nitrate-grown and selenate-grown cells have a constitutive ability to reduce selenite or nitrite. The oxidation of [14C]lactate to 14CO2 coupled to the reduction of selenate or nitrate by cell suspensions was inhibited by CCCP (carbonyl cyanide m-chlorophenylhydrazone), cyanide, and azide. High concentrations of selenite (5 mM) were readily reduced to Se0 by selenate-grown cells, but selenite appeared to block the synthesis of pyruvate dehydrogenase. Tracer experiments with [75Se]selenite indicated that cell suspensions could achieve a rapid and quantitative reduction of selenite to Se0. This reduction was totally inhibited by sulfite, partially inhibited by selenate or nitrite, but unaffected by sulfate or nitrate. Cell suspensions could reduce thiosulfate, but not sulfite, to sulfide. These results suggest that reduction of selenite to Se0 may proceed, in part, by some of the components of a dissimilatory system for sulfur oxyanions. Images

Oremland, Ronald S.; Blum, Jodi Switzer; Culbertson, Charles W.; Visscher, Pieter T.; Miller, Laurence G.; Dowdle, Phillip; Strohmaier, Frances E.

1994-01-01

165

Media composition: energy sources and metabolism.  

PubMed

The preparation of defined culture media for embryo development has progressed from simple chemically defined media based on Krebs-Ringer bicarbonate, supplemented with glucose, bovine plasma albumin, antibiotics and utilizing a CO(2)-bicarbonate buffering system to more complete systems based around studies on the physiology and metabolism of the mammalian embryo. Although the concentration of substrates used in media can vary, there are many components that are quintessentially important for embryo development such as energy sources, that play a vital role in regulation of metabolism and hence viability. Here we describe the role of energy substrates within culture media and outline assays which can be utilized to measure embryo metabolism as a mechanism for determining embryo physiology and viability. PMID:22829370

Zander-Fox, Deirdre; Lane, Michelle

2012-01-01

166

Metabolism of the Plasticizer di-n-Butylphthalate by Pseudomonas pseudoalcaligenes Under Anaerobic Conditions, with Nitrate as the Only Electron Acceptor  

PubMed Central

The metabolism of di-n-butylphthalate by a denitrifying strain of Pseudomonas pseudoalcaligenes B20b1 was studied under anaerobic conditions, with nitrate as the only electron acceptor. Thin-layer chromatography and mass spectral analysis of culture extracts (20 days at 30°C) showed mono-n-butylphthalate and phthalic acid as the only products, suggesting that one butanol moiety served essentially as the carbon source for growth and denitrification. N2 and N2O were detected by gas chromatography. In contrast to aerobic metabolism, phthalate was not degraded further if nitrate was the only electron acceptor.

Benckiser, G.; Ottow, J. C. G.

1982-01-01

167

Effect of coronary bypass surgery on anaerobic myocardial lactate metabolism during pacing-induced angina pectoris.  

PubMed

Myocardial lactate metabolism was studied by coronary sinus catheterization in nine patients before and 8-12 months after coronary bypass surgery. Measurements were performed at rest and during atrial pacing increased to a heart rate which produced strong chest pain. The estimation of myocardial lactate extraction and release was facilitated by a constant rate infusion of 14C lactate and coronary sinus blood flow (CSBF) was measured by thermodilution. Pre-operatively strong chest pain could be elicited in all patients and isotope data indicated a significant myocardial lactate release in all of them, although the net a-cs difference was negative in only half of them. After bypass surgery the maximum tolerable heart rate was increased by 23 beats min-1 and chest pain both at heart rate 110 beats min-1 and at the highest heart rate achieved was reduced or absent in eight of the nine patients. The increase in chest pain during pacing was quantitatively related to the increase in myocardial lactate release, and the correlation between these two variables followed the same course after the operation as it did before. It is concluded that the improvement in chest pain limited cardiac performance after bypass surgery is well correlated with the improvement in myocardial aerobic metabolism. PMID:1769187

Kaijser, L; Gunnes, S; Berglund, B

1991-11-01

168

The role of Klotho in energy metabolism  

PubMed Central

A disproportionate expansion of white adipose tissue and abnormal recruitment of adipogenic precursor cells can not only lead to obesity but also impair glucose metabolism, which are both common causes of insulin resistance and diabetes mellitus. The development of novel and effective therapeutic strategies to slow the progression of obesity, diabetes mellitus and their associated complications will require improved understanding of adipogenesis and glucose metabolism. Klotho might have a role in adipocyte maturation and systemic glucose metabolism. Klotho increases adipocyte differentiation in vitro, and mice that lack Klotho activity are lean owing to reduced white adipose tissue accumulation; moreover, mice that lack the Kl gene (which encodes Klotho) are resistant to obesity induced by a high-fat diet. Knockout of Kl in leptin-deficient Lepob/ob mice reduces obesity and increases insulin sensitivity, which lowers blood glucose levels. Energy metabolism might also be influenced by Klotho. However, further studies are needed to explore the possibility that Klotho could be a novel therapeutic target to reduce obesity and related complications, and to determine whether and how Klotho might influence the regulation and function of a related protein, ?-Klotho, which is also involved in energy metabolism.

Razzaque, M. Shawkat

2013-01-01

169

Energy Metabolism in Human Erythrocytes  

PubMed Central

Exposure of red cells to fluoride produces a variety of metabolic alterations, most of which are based upon the secondary effects of enolase inhibition, which reduces pyruvate synthesis and interferes with the regeneration of diphosphopyridine nucleotide (NAD). Adenosine triphosphate (ATP) is consumed in the hexokinase and phosphofructokinase reactions but is not regenerated since the deficiency of NAD limits glyceraldehyde phosphate dehydrogenase. ATP depletion in the presence of fluoride and calcium induces a massive loss of cations and water. Of the other known sites of ATP utilization, membrane-bound ATPase is inhibited by fluoride, but the incorporation of fatty acids into membrane phospholipids is unaffected until ATP is depleted. The addition of methylene blue to fluoride-treated red cells regenerates NAD, permitting triose oxidation and the generation of 3-phosphoglycerate and 2,3-diphosphoglycerate. Enolase inhibition is then partially overcome by mass action, and sufficient glycolysis proceeds to maintain the concentration of ATP. This in turn prevents the massive cation and water loss, and permits membrane phospholipid renewal to proceed. Membrane ATPase activity is not restored by the oxidant so that normal cation leakage remains unopposed by cation pumping in red cells exposed to the combination of fluoride and methylene blue.

Feig, Stephen A.; Shohet, Stephen B.; Nathan, David G.

1971-01-01

170

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

PubMed Central

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.

Gijzen, H J; Barugahare, M

1992-01-01

171

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

Microsoft Academic Search

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

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

2008-01-01

172

High Ethanol Titers from Cellulose by Using Metabolically Engineered Thermophilic, Anaerobic Microbes ? † ‡  

PubMed Central

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.

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.

2011-01-01

173

Optimization of parameters for anaerobic co-metabolic degradation of TBBPA.  

PubMed

The addition of different carbon and nitrogen sources can promote tetrabromobisphenol A degradation to varying degrees under co-metabolism process. A kinetic model was developed to evaluate the degradation efficiency using different carbon and nitrogen sources. Sodium formate was found to be the best carbon source for tetrabromobisphenol A degradation. The degradation rate reached 96.2% with a half-life of 4.1d. Nitrogen supplementation can also accelerate tetrabromobisphenol A degradation. Organic nitrogen is generally better than inorganic nitrogen. A response surface methodology based on the central composite design was applied to determine the optimum conditions. It showed that concentration of sodium formate, yeast extraction, tetrabromobisphenol A, and inoculum size of microorganism were important factors, and the interaction between either of two variables played different roles. Under the optimum conditions (sodium formate 11.5mg/L, yeast extraction 2.5mg/L, TBBPA 1.1mg/L and inoculum size 3.4%), TBBPA degradation rate reached the maximum. PMID:24063822

Peng, Xingxing; Jia, Xiaoshan

2013-08-31

174

The Effects of Cholera Toxin on Cellular Energy Metabolism  

PubMed Central

Multianalyte microphysiometry, a real-time instrument for simultaneous measurement of metabolic analytes in a microfluidic environment, was used to explore the effects of cholera toxin (CTx). Upon exposure of CTx to PC-12 cells, anaerobic respiration was triggered, measured as increases in acid and lactate production and a decrease in the oxygen uptake. We believe the responses observed are due to a CTx-induced activation of adenylate cyclase, increasing cAMP production and resulting in a switch to anaerobic respiration. Inhibitors (H-89, brefeldin A) and stimulators (forskolin) of cAMP were employed to modulate the CTx-induced cAMP responses. The results of this study show the utility of multianalyte microphysiometry to quantitatively determine the dynamic metabolic effects of toxins and affected pathways.

Snider, Rachel M.; McKenzie, Jennifer R.; Kraft, Lewis; Kozlov, Eugene; Wikswo, John P.; Cliffel, David E.

2010-01-01

175

Chemerin analog regulates energy metabolism in sheep.  

PubMed

Accumulating data suggest a relationship between chemerin and energy metabolism. Our group previously described gene cloning, expression analysis and the regulatory mechanism of chemerin and its own receptor in mice and cattle. The objective of the present study was to investigate the physiological effect of chemerin on endocrine changes and energy metabolism in sheep using a biologically stable chemerin analog. The chemerin analog was intravenously administrated (100 or 500?µg/head) to sheep, and plasma insulin and metabolites (glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and high-density lipoprotein (HDL) cholesterol) were analyzed. The chemerin analog dramatically increased the insulin levels, and glucose levels were decreased. NEFA levels were slightly decreased at 20?min but then increased gradually from 60 to 180?min after analog administration. In addition, injection of the chemerin analog immediately increased triglyceride and total cholesterol but not HDL levels. These results suggested that chemerin analog regulated insulin secretion related to glucose metabolism and the release of triglycerides in sheep in vivo. This study provides new information about endocrine and metabolic changes in response to chemerin in sheep. PMID:22435632

Suzuki, Yutaka; Song, Sang-Houn; Sato, Katsuyoshi; So, Kyoung-Ha; Ardiyanti, Astrid; Kitayama, Shun; Hong, Yeon-Hee; Lee, Sung-Dae; Choi, Ki-Choon; Hagino, Akihiko; Katoh, Kazuo; Roh, Sang-gun

2012-02-10

176

Role of oxytocin in energy metabolism.  

PubMed

The basic mechanisms that lead obesity are not fully understood; however, several peptides undoubtedly play a role in regulating body weight. Obesity, a highly complex metabolic disorder, involves central mechanisms that control food intake and energy expenditure. Previous studies have shown that central or peripheral oxytocin administration induces anorexia. Recently, in an apparent discrepancy, rodents that were deficient in oxytocin or the oxytocin receptor were shown to develop late-onset obesity without changing their total food intake, which indicates the physiological importance of oxytocin to body metabolism. Oxytocin is synthesized not only within magnocellular and parvocellular neurons but also in several organs, including the ovary, uterus, placenta, testis, thymus, kidney, heart, blood vessels, and skin. The presence of oxytocin receptors in neurons, the myometrium and myoepithelial cells is well recognized; however, this receptor has also been identified in other tissues, including the pancreas and adipose tissue. The oxytocin receptor is a typical class I G protein-coupled receptor that is primarily linked to phospholipase C-? via Gq proteins but can also be coupled to other G proteins, leading to different functional effects. In this review, we summarize the present knowledge of the effects of oxytocin on controlling energy metabolism, focusing primarily on the role of oxytocin on appetite regulation, thermoregulation, and metabolic homeostasis. PMID:23628372

Chaves, Valéria Ernestânia; Tilelli, Cristiane Queixa; Brito, Nilton Almeida; Brito, Márcia Nascimento

2013-04-26

177

Time course of anaerobic and aerobic energy expenditure during short-term exhaustive running in athletes.  

PubMed

The aim of the present study was to investigate the time course of aerobic and anaerobic energy yield during supramaximal exhaustive running on the treadmill in sprint and endurance athletes. In addition, the relationships between O2 deficit, excess post-exercise O2 consumption (EPOC) and peak post-exercise blood lactate concentration (peak BLa) values were examined, Oxygen uptake during the exhaustive run and 15 min recovery period was measured using a breath-by-breath method. The accumulated O2 deficit was calculated by an extrapolation procedure. Total running time was the same for eight male sprint runners (49.5 +/- 6.0s) and for six male endurance athletes (49.4 +/- 5.3 s). The sprint group had significantly higher O2 deficit (p < 0.01) during the run as well as higher peak BLa (p < 0.05) and EPOC (p < 0.01) after the run than the endurance group. The relative contribution of anaerobic energy yield decreased from 80% to 60% during the first 15 s of the exhaustive run in both groups. The VO2 peaked and was almost unchanged from 25th to 40th s of the run in both groups, although only 79% of their VO2max was attained. The relative contribution of aerobic energy yield was significantly higher (p < 0.05) in the endurance (54-63%) than in the sprint group (43-47%) during the second half of the run. No correlation was found between the O2 deficit and EPOC but peak BLa correlated significantly (p < 0.05) with the O2 deficit (r = 0.53) and EPOC (r = 0.53). In conclusion, the energy release of the sprint and endurance athletes was different only during the second half of the exhaustive supramaximal run, when the sprinters used more the anaerobic and endurance athletes aerobic pathways for energy production. PMID:8776206

Nummela, A; Rusko, H

1995-11-01

178

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

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.

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

2013-01-01

179

Microbial anaerobic digestion (bio-digesters) as an approach to the decontamination of animal wastes in pollution control and the generation of renewable energy.  

PubMed

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

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

2013-09-17

180

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

SciTech Connect

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.

Miller, Lance D [ORNL; Mosher, Jennifer J [ORNL; Venkateswaran, Amudhan [ORNL; Yang, Zamin Koo [ORNL; Palumbo, Anthony Vito [ORNL; Phelps, Tommy Joe [ORNL; Podar, Mircea [ORNL; Schadt, Christopher Warren [ORNL; Keller, Martin [ORNL

2010-01-01

181

Influence of temperature on energetics of hydrogen metabolism in homoacetogenic, methanogenic, and other anaerobic bacteria  

Microsoft Academic Search

Hydrogen consumption by various thermophilic, mesophilic and\\/or psychrotrophic homoacetogens and methanogens was measured at temperatures between 4 and 80°C. Within the tolerated temperature range H2 was consumed until a final H2 threshold partial pressure was reached. H2 thresholds generally decreased with temperature, parallel to the values calculated from the thermodynamics prevailing under culture conditions, i.e. the Gibbs free energy (?G)

Ralf Conrad; Bettina Wetter

1990-01-01

182

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

PubMed

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 200days. At higher organic loading rates (4.7kg 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

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

2013-09-06

183

Metabolism of homoacetogens  

Microsoft Academic Search

Homoacetogenic bacteria are strictly anaerobic microorganisms that catalyze the formation of acetate from C1 units in their energy metabolism. Most of these organisms are able to grow at the expense of hydrogen plus CO2 as the sole energy source. Hydrogen then serves as the electron donor for CO2 reduction to acetate. The methyl group of acetate is formed from CO2

Gabriele Diekert; Gert Wohlfarth

1994-01-01

184

Anaerobic performance at altitude.  

PubMed

Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax). Conflicting results are reported on anaerobic capacity evaluated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wmax measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7-10 s sprints (i.e. force-velocity test) which solicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance. In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease. PMID:1483803

Coudert, J

1992-10-01

185

Adenosine, energy metabolism and sleep homeostasis.  

PubMed

Adenosine is directly linked to the energy metabolism of cells. In the central nervous system (CNS) an increase in neuronal activity enhances energy consumption as well as extracellular adenosine concentrations. In most brain areas high extracellular adenosine concentrations, through A1 adenosine receptors, decrease neuronal activity and thus the need for energy. Adenosine may be a final common pathway for various sleep factors. We have identified a relatively specific area, the basal forebrain (BF), which appears to be central in the regulation/execution of recovery sleep after sleep deprivation (SD), or prolonged wakefulness. Adenosine concentration increases in this area during SD, and this increase induces sleep while prevention of the increase during SD abolishes recovery sleep. The increase in adenosine is associated with local changes in energy metabolism as indicated by increases in levels of pyruvate and lactate and increased phosphorylation of AMP-activated protein kinase. The increases in adenosine and sleep are associated with intact cholinergic system since specific lesion of the BF cholinergic cells abolishes both. Whether adenosine during SD is produced by the cholinergic neurons or astrocytes associated with them remains to be explored. An interesting, but so far unexplored question regards the relationship between the local, cortical regulation of sleep homeostasis and the global regulation of the state of sleep as executed by lower brain mechanisms, including the BF. The increase in adenosine concentration during SD also in cortical areas suggests that adenosine may have a role in the local regulation of sleep homeostasis. The core of sleep need is probably related to primitive functions of life, like energy metabolism. It can be noted that this assumption in no way excludes the possibility that later in evolution additional functions may have developed, e.g., related to complex neuronal network functions like memory and learning. PMID:20970361

Porkka-Heiskanen, Tarja; Kalinchuk, Anna V

2010-10-20

186

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

PubMed

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

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

2006-08-28

187

Mitochondrial CB? receptors regulate neuronal energy metabolism.  

PubMed

The mammalian brain is one of the organs with the highest energy demands, and mitochondria are key determinants of its functions. Here we show that the type-1 cannabinoid receptor (CB(1)) is present at the membranes of mouse neuronal mitochondria (mtCB(1)), where it directly controls cellular respiration and energy production. Through activation of mtCB(1) receptors, exogenous cannabinoids and in situ endocannabinoids decreased cyclic AMP concentration, protein kinase A activity, complex I enzymatic activity and respiration in neuronal mitochondria. In addition, intracellular CB(1) receptors and mitochondrial mechanisms contributed to endocannabinoid-dependent depolarization-induced suppression of inhibition in the hippocampus. Thus, mtCB(1) receptors directly modulate neuronal energy metabolism, revealing a new mechanism of action of G protein-coupled receptor signaling in the brain. PMID:22388959

Bénard, Giovanni; Massa, Federico; Puente, Nagore; Lourenço, Joana; Bellocchio, Luigi; Soria-Gómez, Edgar; Matias, Isabel; Delamarre, Anna; Metna-Laurent, Mathilde; Cannich, Astrid; Hebert-Chatelain, Etienne; Mulle, Christophe; Ortega-Gutiérrez, Silvia; Martín-Fontecha, Mar; Klugmann, Matthias; Guggenhuber, Stephan; Lutz, Beat; Gertsch, Jürg; Chaouloff, Francis; López-Rodríguez, María Luz; Grandes, Pedro; Rossignol, Rodrigue; Marsicano, Giovanni

2012-03-04

188

Substrate-Level Phosphorylation Is the Primary Source of Energy Conservation during Anaerobic Respiration of Shewanella oneidensis Strain MR-1? #  

PubMed Central

It is well established that respiratory organisms use proton motive force to produce ATP via F-type ATP synthase aerobically and that this process may reverse during anaerobiosis to produce proton motive force. Here, we show that Shewanella oneidensis strain MR-1, a nonfermentative, facultative anaerobe known to respire exogenous electron acceptors, generates ATP primarily from substrate-level phosphorylation under anaerobic conditions. Mutant strains lacking ackA (SO2915) and pta (SO2916), genes required for acetate production and a significant portion of substrate-level ATP produced anaerobically, were tested for growth. These mutant strains were unable to grow anaerobically with lactate and fumarate as the electron acceptor, consistent with substrate-level phosphorylation yielding a significant amount of ATP. Mutant strains lacking ackA and pta were also shown to grow slowly using N-acetylglucosamine as the carbon source and fumarate as the electron acceptor, consistent with some ATP generation deriving from the Entner-Doudoroff pathway with this substrate. A deletion strain lacking the sole F-type ATP synthase (SO4746 to SO4754) demonstrated enhanced growth on N-acetylglucosamine and a minor defect with lactate under anaerobic conditions. ATP synthase mutants grown anaerobically on lactate while expressing proteorhodopsin, a light-dependent proton pump, exhibited restored growth when exposed to light, consistent with a proton-pumping role for ATP synthase under anaerobic conditions. Although S. oneidensis requires external electron acceptors to balance redox reactions and is not fermentative, we find that substrate-level phosphorylation is its primary anaerobic energy conservation strategy. Phenotypic characterization of an ackA deletion in Shewanella sp. strain MR-4 and genomic analysis of other sequenced strains suggest that this strategy is a common feature of Shewanella.

Hunt, Kristopher A.; Flynn, Jeffrey M.; Naranjo, Belen; Shikhare, Indraneel D.; Gralnick, Jeffrey A.

2010-01-01

189

Substrate-level phosphorylation is the primary source of energy conservation during anaerobic respiration of Shewanella oneidensis strain MR-1.  

PubMed

It is well established that respiratory organisms use proton motive force to produce ATP via F-type ATP synthase aerobically and that this process may reverse during anaerobiosis to produce proton motive force. Here, we show that Shewanella oneidensis strain MR-1, a nonfermentative, facultative anaerobe known to respire exogenous electron acceptors, generates ATP primarily from substrate-level phosphorylation under anaerobic conditions. Mutant strains lacking ackA (SO2915) and pta (SO2916), genes required for acetate production and a significant portion of substrate-level ATP produced anaerobically, were tested for growth. These mutant strains were unable to grow anaerobically with lactate and fumarate as the electron acceptor, consistent with substrate-level phosphorylation yielding a significant amount of ATP. Mutant strains lacking ackA and pta were also shown to grow slowly using N-acetylglucosamine as the carbon source and fumarate as the electron acceptor, consistent with some ATP generation deriving from the Entner-Doudoroff pathway with this substrate. A deletion strain lacking the sole F-type ATP synthase (SO4746 to SO4754) demonstrated enhanced growth on N-acetylglucosamine and a minor defect with lactate under anaerobic conditions. ATP synthase mutants grown anaerobically on lactate while expressing proteorhodopsin, a light-dependent proton pump, exhibited restored growth when exposed to light, consistent with a proton-pumping role for ATP synthase under anaerobic conditions. Although S. oneidensis requires external electron acceptors to balance redox reactions and is not fermentative, we find that substrate-level phosphorylation is its primary anaerobic energy conservation strategy. Phenotypic characterization of an ackA deletion in Shewanella sp. strain MR-4 and genomic analysis of other sequenced strains suggest that this strategy is a common feature of Shewanella. PMID:20400539

Hunt, Kristopher A; Flynn, Jeffrey M; Naranjo, Belén; Shikhare, Indraneel D; Gralnick, Jeffrey A

2010-04-16

190

Measurement of anaerobic work capacities in humans.  

PubMed

The development of simple, noninvasive tests of work capacities, underpinned primarily by anaerobic metabolism, proliferated in the early 1970s. A 30-second maximal cycle test developed at the Wingate Institute initiated efforts to develop work tests of anaerobic capacities. Such tests can be developed using any ergometer which simulates competitive conditions and enables an accurate determination of mechanical work output. A 10-second all-out test is commonly used to measure maximal work output generated primarily via the hydrolysis of high-energy phosphagens (i.e. the alactic work capacity). In contrast, a variety of constant-load and all-out tests of anaerobic (alactic plus lactic) work capacity have been proposed. It has been suggested that all-out tests provide more information about physiological capabilities and are easier to apply than constant-load tests. The optimal duration for an all-out test of anaerobic work capacity is proposed at 30 seconds, a duration which may also provide the basis for the development of accurate field tests of anaerobic capacity. There is evidence that the y-intercept of the maximal work-derivation regression is a valid work estimate of anaerobic capacity in athletes, although its utility is undermined by the number of tests required for its derivation. PMID:7740245

Green, S

1995-01-01

191

High-Intensity Interval Training, Solutions to the Programming Puzzle : Part II: Anaerobic Energy, Neuromuscular Load and Practical Applications.  

PubMed

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[Formula: see text]O2max] 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[Formula: see text]O2max 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

Buchheit, Martin; Laursen, Paul B

2013-10-01

192

Quercetin alters energy metabolism in swimming mice.  

PubMed

Quercetin has been demonstrated to be effective in increasing physical endurance in mice and humans. However, the mechanisms involved are not fully understood. In this study, male Kunming mice were fed a diet containing 0.1% quercetin for 14 days before swimming for 60 min. The overall serum metabolic profile was investigated by a ¹H nuclear magnetic resonance-based metabolomic approach. Serum glucose, lactate, nonesterified fatty acids (NEFA), and nonprotein nitrogen (NPN), as well as hepatic and muscular glycogen were measured biochemically. The results of metabolomic analysis showed that swimming induced a significant change in serum metabolic profile. Relative increases in the levels of lactate, alanine, low-density lipoprotein-very low-density lipoprotein, and unsaturated fatty acids, and decreases in choline, phosphocholine, and glucose were observed after swimming. With quercetin supplementation, these changes were attenuated. The results of biochemical assays were consistent with the data obtained from metabolomic analysis, in that serum NEFA was increased while lactate and NPN decreased after exposed to quercetin in swimming mice. Similar change in NEFA was also found in liver and gastrocnemius muscle tissues. Our current findings suggest that quercetin alters energy metabolism in swimming mice and increased lipolysis may contribute to the actions of quercetin on physical endurance. PMID:22765761

Wu, Jianquan; Gao, Weina; Wei, Jingyu; Yang, Jijun; Pu, Lingling; Guo, Changjiang

2012-07-10

193

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

PubMed

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

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

2008-04-21

194

Role of interleukin 1 and tumor necrosis factor on energy metabolism in rabbits  

SciTech Connect

A study of the combined effects of intravenous infusion of the recombinant cytokines beta-interleukin 1 (IL-1) and alpha-tumor necrosis factor (TNF) on energy substrate metabolism in awake, conditioned, adult rabbits was performed. After a 2-h basal or control period, 48-h fasted rabbits were administered TNF and IL-1 as a bolus (5 micrograms/kg) followed by a continuous intravenous infusion (25 ng.kg-1.min-1) for 3 h. Significant increases in plasma lactate (P less than 0.01), glucose (P less than 0.01), and triglycerides (P less than 0.05) occurred during the combined infusion of IL-1 and TNF, whereas neither cytokine alone had no effect. There was a 33% increase in the rate of glucose appearance (P less than 0.05), but glucose clearance was not altered compared with the control period. Glucose oxidation increased during the combined cytokine infusion period and glucose recycling increased by 600% (P less than 0.002). Lactic acidosis and decreased oxygen consumption, as a result of the cytokine infusions, indicated development of anaerobic glycolytic metabolism. A reduction in the activity state of hepatic mitochondrial pyruvate dehydrogenase (65 vs. 82% in control animals, P less than 0.05) was consistent with the observed increase in anaerobic glycolysis. Thus the combined infusion of IL-1 and TNF in rabbits produces metabolic manifestations seen in severe injury and sepsis in human patients and, as such, may account for the profound alterations of energy metabolism seen in these conditions.

Tredget, E.E.; Yu, Y.M.; Zhong, S.; Burini, R.; Okusawa, S.; Gelfand, J.A.; Dinarello, C.A.; Young, V.R.; Burke, J.F.

1988-12-01

195

Understanding transportation energy and technical metabolism of construction waste recycling  

Microsoft Academic Search

Energy and resource efficiencies are both critical to achieve building design and construction sustainability. Embodied energy is a measure of the energy required to produce, install, and maintain materials, while technical metabolism enhances building design recyclability. Nearly all types of materials can be recycled. However, the technical metabolism of the materials depends on the existence of a market for these

Wai K. Chong; Christopher Hermreck

2010-01-01

196

Elevated muscle glycogen and anaerobic energy production during exhaustive exercise in man.  

PubMed Central

1. The effect of elevated muscle glycogen on anaerobic energy production, and glycogenolytic and glycolytic rates was examined in man by using the one-legged knee extension model, which enables evaluation of metabolism in a well-defined muscle group. 2. Six subjects performed very intense exercise to exhaustion (EX1) with one leg with normal glycogen (control) and one with a very high concentration (HG). With each leg, the exhaustive exercise was repeated after 1 h of recovery (EX2). Prior to and immediately after each exercise bout, a muscle biopsy was taken from m. vastus lateralis of the active leg for determination of glycogen, lactate, creatine phosphate (CP) and nucleotide concentrations. Measurements of leg blood flow and femoral arterial-venous differences for oxygen content, lactate, glucose, free fatty acids and potassium were performed before and regularly during the exhaustive exercises. 3. Muscle glycogen concentration prior to EX1 was 87.0 and 176.8 mmol (kg wet wt)-1 for the control and HG leg, respectively, and the decreases during exercise were 26.3 (control) and 25.6 (HG) mmol (kg wet wt)-1. The net glycogen utilization rate was not related to pre-exercise muscle glycogen concentration. Muscle lactate concentration at the end of EX1 was 18.8 (control) and 16.1 (HG) mmol (kg wet wt)-1, and the net lactate production (including lactate release) was 26.5 (control) and 23.6 (HG) mmol (kg wet wt)-1. Rate of lactate production was unrelated to initial muscle glycogen level. Time to exhaustion for EX1 was the same for the control leg (2.82 min) and HG leg (2.92 min). 4. Muscle glycogen concentration before EX2 was 14 mmol (kg wet wt)-1 lower than prior to EX1. During EX2 the muscle glycogen decline of 19.6 mmol (kg wet wt)-1 for the control leg was less than for the HG leg (26.2 mmol (kg wet wt)-1). The muscle lactate concentrations at the end of EX2 were about 7-8 mmol (kg wet wt)-1 lower compared to EX1, and the net lactate production was reduced by 40%. The exercise time during EX2 was 0.35 min shorter for the control leg, while no difference was observed for the HG leg. 5. Total reduction in ATP and CP was similar during the four exercise bouts, while a higher accumulation of inosine monophosphate (IMP) occurred during EX2 for the control leg (0.72 mmol (kg wet wt)-1) compared to the HG leg (0.20 mmol (kg wet wt)-1).(ABSTRACT TRUNCATED AT 400 WORDS)

Bangsbo, J; Graham, T E; Kiens, B; Saltin, B

1992-01-01

197

Muscle energy stores and stroke rates of emperor penguins: implications for muscle metabolism and dive performance.  

PubMed

In diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. During complete ischemia, ATP production is dependent on the size of the myoglobin oxygen (O(2)) store and the concentrations of phosphocreatine (PCr) and glycogen (Gly). Therefore, we measured PCr and Gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle O(2) and those energy stores under conditions of complete ischemia and a previously determined muscle metabolic rate. We also analyzed stroke rate to assess muscle workload variation during dives and evaluate potential limitations on the model. Measured PCr and Gly concentrations, 20.8 and 54.6 mmol kg(-1), respectively, were similar to published values for nondiving animals. The model demonstrated that PCr and Gly provide a large anaerobic energy store, even for dives longer than 20 min. Stroke rate varied throughout the dive profile, indicating muscle workload was not constant during dives as was assumed in the model. The stroke rate during the first 30 s of dives increased with increased dive depth. In extremely long dives, lower overall stroke rates were observed. Although O(2) consumption and energy store depletion may vary during dives, the model demonstrated that PCr and Gly, even at concentrations typical of terrestrial birds and mammals, are a significant anaerobic energy store and can play an important role in the emperor penguin's ability to perform long dives. PMID:22418705

Williams, Cassondra L; Sato, Katsufumi; Shiomi, Kozue; Ponganis, Paul J

2012-02-29

198

Nitric oxide and energy metabolism in mammals.  

PubMed

Nitric oxide (NO) is a signaling molecule synthesized from L-arginine by NO synthase in animals. Increasing evidence shows that NO regulates the mammalian metabolism of energy substrates and that these effects of NO critically depend on its concentrations at the reaction site and the period of exposure. High concentrations of NO (in the micromolar range) irreversibly inhibit complexes I, II, III, IV, and V in the mitochondrial respiratory chain, whereas physiological levels of NO (in the nanomolar range) reversibly reduce cytochomrome oxidase. Thus, NO reduces oxygen consumption by isolated mitochondria to various extents. In intact cells, through cGMP and AMP-activated protein kinase signaling, physiological levels of NO acutely stimulate uptake and oxidation of glucose and fatty acids by skeletal muscle, heart, liver, and adipose tissue, while inhibiting the synthesis of glucose, glycogen and fat in the insulin-sensitive tissues, and enhancing lipolysis in white adipocytes. Chronic effects of physiological levels of NO in vivo include stimulation of angiogenesis, blood flow, mitochondrial biogenesis, and brown adipocyte development. Modulation of NO-mediated pathways through dietary supplementation with L-arginine or its precursor L-citrulline may provide an effective, practical strategy to prevent and treat metabolic syndrome, including obesity, diabetes, and dyslipidemia in mammals, including humans. PMID:23553707

Dai, Zhaolai; Wu, Zhenlong; Yang, Ying; Wang, Junjun; Satterfield, M Carey; Meininger, Cynthia J; Bazer, Fuller W; Wu, Guoyao

2013-03-29

199

A comparative genomic analysis of energy metabolism in sulfate reducing bacteria and archaea.  

PubMed

The number of sequenced genomes of sulfate reducing organisms (SRO) has increased significantly in the recent years, providing an opportunity for a broader perspective into their energy metabolism. In this work we carried out a comparative survey of energy metabolism genes found in 25 available genomes of SRO. This analysis revealed a higher diversity of possible energy conserving pathways than classically considered to be present in these organisms, and permitted the identification of new proteins not known to be present in this group. The Deltaproteobacteria (and Thermodesulfovibrio yellowstonii) are characterized by a large number of cytochromes c and cytochrome c-associated membrane redox complexes, indicating that periplasmic electron transfer pathways are important in these bacteria. The Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. However, despite the absence of a periplasmic space, a few extracytoplasmic membrane redox proteins were detected in the Gram-positive bacteria. Several ion-translocating complexes were detected in SRO including H(+)-pyrophosphatases, complex I homologs, Rnf, and Ech/Coo hydrogenases. Furthermore, we found evidence that cytoplasmic electron bifurcating mechanisms, recently described for other anaerobes, are also likely to play an important role in energy metabolism of SRO. A number of cytoplasmic [NiFe] and [FeFe] hydrogenases, formate dehydrogenases, and heterodisulfide reductase-related proteins are likely candidates to be involved in energy coupling through electron bifurcation, from diverse electron donors such as H(2), formate, pyruvate, NAD(P)H, ?-oxidation, and others. In conclusion, this analysis indicates that energy metabolism of SRO is far more versatile than previously considered, and that both chemiosmotic and flavin-based electron bifurcating mechanisms provide alternative strategies for energy conservation. PMID:21747791

Pereira, Inês A Cardoso; Ramos, Ana Raquel; Grein, Fabian; Marques, Marta Coimbra; da Silva, Sofia Marques; Venceslau, Sofia Santos

2011-04-19

200

A Comparative Genomic Analysis of Energy Metabolism in Sulfate Reducing Bacteria and Archaea  

PubMed Central

The number of sequenced genomes of sulfate reducing organisms (SRO) has increased significantly in the recent years, providing an opportunity for a broader perspective into their energy metabolism. In this work we carried out a comparative survey of energy metabolism genes found in 25 available genomes of SRO. This analysis revealed a higher diversity of possible energy conserving pathways than classically considered to be present in these organisms, and permitted the identification of new proteins not known to be present in this group. The Deltaproteobacteria (and Thermodesulfovibrio yellowstonii) are characterized by a large number of cytochromes c and cytochrome c-associated membrane redox complexes, indicating that periplasmic electron transfer pathways are important in these bacteria. The Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. However, despite the absence of a periplasmic space, a few extracytoplasmic membrane redox proteins were detected in the Gram-positive bacteria. Several ion-translocating complexes were detected in SRO including H+-pyrophosphatases, complex I homologs, Rnf, and Ech/Coo hydrogenases. Furthermore, we found evidence that cytoplasmic electron bifurcating mechanisms, recently described for other anaerobes, are also likely to play an important role in energy metabolism of SRO. A number of cytoplasmic [NiFe] and [FeFe] hydrogenases, formate dehydrogenases, and heterodisulfide reductase-related proteins are likely candidates to be involved in energy coupling through electron bifurcation, from diverse electron donors such as H2, formate, pyruvate, NAD(P)H, ?-oxidation, and others. In conclusion, this analysis indicates that energy metabolism of SRO is far more versatile than previously considered, and that both chemiosmotic and flavin-based electron bifurcating mechanisms provide alternative strategies for energy conservation.

Pereira, Ines A. Cardoso; Ramos, Ana Raquel; Grein, Fabian; Marques, Marta Coimbra; da Silva, Sofia Marques; Venceslau, Sofia Santos

2011-01-01

201

Arsenic, Anaerobes, and Autotrophy.  

NASA Astrophysics Data System (ADS)

That microbes have resistance to the toxic arsenic oxyanions arsenite [As(III)] and arsenate [As(V)] has been recognized for some time. More recently it was shown that certain prokaryotes can demonstrate As- dependent growth by conserving the energy gained from the aerobic oxidation of As(III) to As(V), or from the reduction of As(V) to As(III) under anaerobic conditions. During the course of our field studies of two alkaline, hypersaline soda lakes (Mono Lake and Searles Lake, CA) we have discovered several new anaerobic chemo- and photo-autotrophic bacteria that can center their energy gain around the redox reactions between As(III) and As(V). Alkalilimnicola ehrlichii, isolated from the water column of Mono Lake is a nitrate-respiring, As(III)-oxidizing chemoautotroph of the gamma-proteobacteria that has a highly flexible metabolism. It can function either as a facultative anaerobe or as a chemo-autotroph, or as a heterotroph (Hoeft et al., 2007). In contrast, strain MLMS-1 of the delta-proteobacteria was also isolated from Mono Lake, but to date is the first example of an obligate As(V)-respirer that is also an obligate chemo-autotroph, gaining its energy via the oxidation of sulfide to sulfate (Hoeft et al., 2004). Strain SLAS-1, isolated from salt-saturated Searles Lake is a member of the Halananerobiales, and can either grow as a heterotroph (lactate e-donor) or chemo- autotroph (sulfide e-donor) while respiring As(V). The fact that it can achieve this feat at salt-saturation (~ 340 g/L) makes it a true extremophile (Oremland et. al., 2005). Finally, strain PHS-1 isolated from a hot spring on Paoha island in Mono Lake is the first example of a photosynthetic bacterium of the gamma- proteobacteria able to link its growth to As(III)-dependent anoxygenic photosynthesis (Kulp et al., 2008). These novel microbes give us new insights into the evolution of arsenic-based metabolism and their role in the biogeochemical cycling of this toxic element. Hoeft, S.E., et al. 2007. Int. J. Syst. Evol. Microbiol. 57: 514 - 512. Hoeft, S.E, et al. 2004. Appl. Environ. Microbiol. 70: 2741 - 2747. Oremland, R.S., et al. 2005. Science 308: 1305 - 1308. Kulp, T.R. et al. 2008. Science 321: 967 - 970.

Oremland, R. S.

2008-12-01

202

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...

203

Cerebral Energy Metabolism after Subarachnoid Hemorrhage.  

National Technical Information Service (NTIS)

The purpose of this study was to determine the effects of subarachnoid hemorrhage (SAH) on cerebral blood flow and cerebral oxidative metabolism. Average total hemispheric flow was measured utilizing a polarographic technique and the metabolic consumption...

J. M. Fein

1975-01-01

204

Diversity of anaerobic halophilic microorganisms  

Microsoft Academic Search

Life in the presence of high salt concentrations is compatible with life in the absence of oxygen. Halophilic and halotolerant anaerobic prokaryotes are found both in the archaeal and in the bacterial domain, and they display a great metabolic diversity. Many of the representatives of the Halobacteriales (Archaea), which are generally considered aerobes, have the potential of anaerobic growth. Some

Aharon Oren; Roland S. Oremland

2000-01-01

205

Anaerobic balanoposthitis.  

PubMed

To assess the causative role of non-sporing anaerobes in cass of erosive balanoposthitis, anaerobic culture was performed on purulent discharges from 104 patients with penile ulceration, a foul-smelling discharge, and a mixed and motile bacterial flora. Most of 29 culturally confirmed infections were due to mixed anaerobes and eight to single anaerobes. A rapid response to treatment with metronidazole also confirmed the anaerobic cause of the infection. Thus, acute anaerobic balanoposthitis can be readily diagnosed clinically and is easily treated. PMID:6121604

Cree, G E; Willis, A T; Phillips, K D; Brazier, J S

1982-03-20

206

Energy metabolism and the skeleton: Reciprocal interplay  

PubMed Central

The relation between bone remodelling and energy expenditure is an intriguing, and yet unexplained, challenge of the past ten years. In fact, it was only in the last few years that the skeleton was found to function, not only in its obvious roles of body support and protection, but also as an important part of the endocrine system. In particular, bone produces different hormones, like osteocalcin (OC), which influences energy expenditure in humans. The undercarboxylated form of OC has a reduced affinity for hydroxyapatite; hence it enters the systemic circulation more easily and exerts its metabolic functions for the proliferation of pancreatic ?-cells, insulin secretion, sensitivity, and glucose tolerance. Leptin, a hormone synthesized by adipocytes, also has an effect on both bone remodelling and energy expenditure; in fact it inhibits appetite through hypothalamic influence and, in bone, stimulates osteoblastic differentiation and inhibits apoptosis. Leptin and serotonin exert opposite influences on bone mass accrual, but several features suggest that they might operate in the same pathway through a sympathetic tone. Serotonin, in fact, acts via two opposite pathways in controlling bone remodelling: central and peripheral. Serotonin product by the gastrointestinal tract (95%) augments bone formation by osteoblast, whereas brain-derived serotonin influences low bone mineral density and its decrease leads to an increase in bone resorption parameters. Finally, amylin (AMY) acts as a hormone that alters physiological responses related to feeding, and plays a role as a growth factor in bone. In vitro AMY stimulates the proliferation of osteoblasts, and osteoclast differentiation. Here we summarize the evidence that links energy expenditure and bone remodelling, with particular regard to humans.

D'Amelio, Patrizia; Panico, Anna; Spertino, Elena; Isaia, Giovanni Carlo

2012-01-01

207

Gastric Mucosal Energy Metabolism and "Stress Ulceration,"  

PubMed Central

Acute gastric erosions following hemorrhagic shock (stress ulceration) have been attributed to gastric hyperacidity, altered gastric secretion of mucus and an abnormal permeability of the gastric mucosa to H+. This report aims at presenting evidence supporting an alternate hypothesis: the event linking shock-induced gastric mucosal ischemia to mucosal necrosis is a deficit in gastric mucosal energy metabolism. Our experimental procedure consisted of harvesting the stomachs of rats and rabbits by “stop-freeze” (liquid N2) at different intervals after the induction of hemorrhagic shock. Levels of adenosine-phosphates and of glycolytic intermediates in gastric mucosa were measured. We studied the changes in the levels of these substrates produced by shock as well as by factors capable, when combined with shock, of rendering the gastric mucosa more vulnerable to stress ulceration. The influence of shock and of these modifying factors were evaluated by comparison with data from appropriately designed control experiments. In parallel experiments we examined the frequency of stress ulceration (gross and microscopic) under these same standard conditions. There have emerged from these studies a number of observations all based upon data with the highest statistical significance. The data are consonant with the hypothesis stated above: an energy deficit severe enough to cause cellular necrosis is the event linking shock-induced gastric mucosal ischemia and stress ulceration. ImagesFig. 1.Fig. 2.

Menguy, Rene; Masters, Y. F.

1974-01-01

208

Metabolic influences of fiber size in aerobic and anaerobic locomotor muscles of the blue crab, Callinectes sapidus  

Microsoft Academic Search

Diameters of some white locomotor muscle fibers in the adult blue crab, Callinectes sapidus, exceed 500·?m whereas juvenile white fibers are <100·?m. It was hypothesized that aerobically dependent processes, such as metabolic recovery following burst contractions, will be significantly impeded in the large white fibers. In addition, dark aerobic fibers of adults, which rely on aerobic metabolism for both contraction

L. K. Johnson; R. M. Dillaman; D. M. Gay; J. E. Blum; S. T. Kinsey

2004-01-01

209

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

SciTech Connect

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.

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

1999-06-05

210

Anaerobic Digestion in Suspended Growth Bioreactors  

Microsoft Academic Search

\\u000a This chapter concerns the principles of suspended growth anaerobic digestion. The fundamentals of anaerobic metabolism of\\u000a organic matter are first presented. This is followed by presentation of anaerobic process stoichiometry and energetics as\\u000a well as kinetics as these are prerequisites for the design of anaerobic processes. The importance of the feed characteristics\\u000a that make a particular substrate medium or feedstock

Gerasimos Lyberatos; Pratap C. Pullammanappallil

211

Milestones in the History of Research on Cardiac Energy Metabolism.  

PubMed

The present study summarizes the history of research on cardiac metabolism from antiquity till the 21st century. It describes important landmarks regarding the discovery of oxygen and of the 3 steps of cellular respiration, as well as major research on cardiac energy metabolism. For this purpose, we conducted a thorough search of original manuscripts, books, and contemporary reviews published in PubMed. The first views and concepts about the heart's function appear in Greek philosophic manuscripts of 2500 years ago. According to Aristotle, the heart is responsible for heat production, which is essential for life. The understanding of cardiac metabolism awaited new discoveries. The discovery of oxygen during the 18th century, along with the idea of energy conservation, or what is now known as one of the first versions of the first law of thermodynamics, played an important role in initiating the study of energy metabolism in general and heart metabolism later. The discovery of glycolysis, of the Krebs cycle, and of adenosine triphosphate offered a better understanding of cellular respiration, necessary for later research. Indeed, many researchers dedicated their studies to energy metabolism, but Richard John Bing, the renowned German research cardiologist, is the one who guided the exploration of cardiac metabolism, and he is therefore considered to be the father of cardiac energy metabolism. Since then, encouraging new research has been taking place, offering important clinical applications for heart patients. PMID:23351886

Beloukas, Apostolos I; Magiorkinis, Emmanouil; Tsoumakas, Theofanis L; Kosma, Alexandra G; Diamantis, Aristidis

2013-01-23

212

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

SciTech Connect

Highlights: Black-Right-Pointing-Pointer This study demonstrates the feasibility of co-digestion food industrial waste with energy crops. Black-Right-Pointing-Pointer Laboratory batch co-digestion led to improved methane yield and carbon to nitrogen ratio as compared to mono-digestion of industrial waste. Black-Right-Pointing-Pointer Co-digestion was also seen as a means of degrading energy crops with nutrients addition as crops are poor in nutrients. Black-Right-Pointing-Pointer Batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. Black-Right-Pointing-Pointer It was concluded that co-digestion led an over all economically viable process and ensured a constant supply of feedstock. - Abstract: 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.

Nges, Ivo Achu, E-mail: Nges.Ivo_Achu@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden); Escobar, Federico; Fu Xinmei; Bjoernsson, Lovisa [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden)

2012-01-15

213

Energy metabolism in astrocytes: high rate of oxidative metabolism and spatiotemporal dependence on glycolysis\\/glycogenolysis  

Microsoft Academic Search

Astrocytic energy demand is stimulated by K+ and glutamate uptake, signaling processes, responses to neurotransmitters, Ca2+ fluxes, and filopodial motility. Astrocytes derive energy from glycolytic and oxidative pathways, but respiration, with its high-energy yield, provides most adenosine 5? triphosphate (ATP). The proportion of cortical oxidative metabolism attributed to astrocytes (?30%) in in vivo nuclear magnetic resonance (NMR) spectroscopic and autoradiographic

Leif Hertz; Liang Peng; Gerald A Dienel

2007-01-01

214

Anaerobic Metabolism of Cyclohex-1-Ene-1-Carboxylate, a Proposed Intermediate of Benzoate Degradation, by Rhodopseudomonas palustris  

PubMed Central

Anaerobic benzoate degradation by the phototrophic bacterium Rhodopseudomonas palustris has been proposed to proceed via aromatic ring reduction reactions leading to cyclohex-1-ene-1-carboxyl-coenzyme A (CoA) formation. The alicyclic product is then proposed to undergo three ?-oxidation-like modifications resulting in ring cleavage. Illuminated suspensions of benzoate-grown cells converted [7-14C]cyclohex-1-ene-1-carboxylate to intermediates that comigrated with cyclohex-1-ene-1-carboxyl-CoA, 2-hydroxycyclohexanecar-boxyl-CoA, 2-ketocyclohexanecarboxyl-CoA, and pimelyl-CoA by thin-layer chromatography. This set of intermediates was also formed by cells grown anaerobically or aerobically on cyclohex-1-ene-1-carboxylate, indicating that benzoate-grown and cyclohex-1-ene-1-carboxylate-grown cells degrade this alicyclic acid by the same catabolic route. Four enzymatic activities proposed to be required for conversion of cyclohex-1-ene-1-carboxylate to pimelyl-CoA were detected at 3- to 10-fold-higher levels in benzoate-grown cells than in succinate-grown cells. These were cyclohex-1-ene-1-carboxylate-CoA ligase, cyclohex-1-ene-1-carboxyl-CoA hydratase, 2-hydroxycyclohexanecarboxyl-CoA dehydrogenase, and 2-ketocyclohexanecarboxyl-CoA hydrolase (ring cleaving). Pimelyl-CoA was identified in hydrolase reaction mixtures as the product of alicyclic ring cleavage. The results provide a first demonstration of an alicyclic ring cleavage activity. Images

Perrotta, Joseph A.; Harwood, Caroline S.

1994-01-01

215

Energy metabolism in cardiac remodeling and heart failure.  

PubMed

Fatty acids are the main substrates used by mitochondria to provide myocardial energy under normal conditions. During heart remodeling, however, the fuel preference switches to glucose. In the earlier stages of cardiac remodeling, changes in energy metabolism are considered crucial to protect the heart from irreversible damage. Furthermore, low fatty acid oxidation and the stimulus for glycolytic pathway lead to lipotoxicity, acidosis, and low adenosine triphosphate production. While myocardial function is directly associated with energy metabolism, the metabolic pathways could be potential targets for therapy in heart failure. PMID:22990373

Azevedo, Paula S; Minicucci, Marcos F; Santos, Priscila P; Paiva, Sergio A R; Zornoff, Leonardo A M

216

Performance and energy economics of mesophilic and thermophilic digestion in anaerobic hybrid reactor treating coal wastewater.  

PubMed

Two anaerobic hybrid AHRs (AHR), mesophilic (35 °C) and thermophilic (55 °C) were operated with coal wastewater at different hydraulic retention times (HRT) ranging from 3-0.5 to 3.12-0.6d with organic loading rates (OLR) of 1.12-6.72 g L(-1) d(-1). Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg L(-1) and phenolics concentration of 752 mg L(-1) was used as substrate. At each HRT, the thermophilic AHR gave a better performance, measured in terms of phenolics/COD removal and gas production. The specific methane yield was also higher for thermophilic AHR at each HRT compared to mesophilic one. The volatile fatty acid concentration in the effluent increased with the lowering of HRT. The Stover-Kincannon model was applicable at both temperatures and showed higher substrate utilization in thermophilic AHR. Energy economic study of the AHRs revealed that 11,938 MJ d(-1) more energy can be generated using thermophilic AHR than mesophilic. PMID:23138053

Ramakrishnan, Anushuya; Surampalli, Rao Y

2012-09-29

217

One Carbon Metabolism in Anaerobic Bacteria. Organic Acid and Methane Production. Progress Report, June 1985-May 1986.  

National Technical Information Service (NTIS)

Our project focussed on understanding of one and multicarbon metabolism in acetogenic and methanogenic bacteria. The studies with acetate catabolism pathway in Methanosarcina barkeri showed involvement of methyl reductase, methyl coenzyme M and carbon mon...

J. G. Zeikus

1986-01-01

218

Pregnane X receptor and constitutive androstane receptor at the crossroads of drug metabolism and energy metabolism.  

PubMed

The pregnane X receptor (PXR) and the constitutive androstane receptor (CAR) are two closely related and liver-enriched nuclear hormone receptors originally defined as xenobiotic receptors. PXR and CAR regulate the transcription of drug-metabolizing enzymes and transporters, which are essential in protecting our bodies from the accumulation of harmful chemicals. An increasing body of evidence suggests that PXR and CAR also have an endobiotic function that impacts energy homeostasis through the regulation of glucose and lipids metabolism. Of note and in contrast, disruptions of energy homeostasis, such as those observed in obesity and diabetes, also have a major impact on drug metabolism. This review will focus on recent progress in our understanding of the integral role of PXR and CAR in drug metabolism and energy homeostasis. PMID:20736325

Gao, Jie; Xie, Wen

2010-08-24

219

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

PubMed Central

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 of tricarboxylic acid (TCA) cyle metabolites and ATP in the astrocytic mitochondria incubated with lactate. Oxamate, an inhibitor of lactate dehydrogenase (LDH), abolished mitochondrial lactate consumption. Electrophoretic and fluorescence microscopic analyses helped localize LDH in the mitochondria. Taken together, this study implicates lactate as an important contributor to ATP metabolism in the brain, a finding that may significantly change our notion of how this important organ manipulates its energy budget.

Lemire, Joseph; Mailloux, Ryan J.; Appanna, Vasu D.

2008-01-01

220

Metabolism and energy requirements in pantothenate kinase-associated neurodegeneration.  

PubMed

Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive disorder of coenzyme A homeostasis caused by defects in the mitochondrial pantothenate kinase 2. Patients with PKAN present with a progressive neurological decline and brain iron accumulation, but general energy balance and nutrition status among these patients has not been reported. To determine if defects in PANK2 change basic energy metabolism in humans, we measured body composition, resting energy expenditure, dietary intake, and blood metabolites among 16 subjects with PKAN. Subjects had a broad range of disease severity but, despite the essential role of coenzyme A in energy metabolism, the subjects had remarkably normal body composition, dietary intake and energy metabolism compared to population normal values. We did observe increased resting energy expenditure associated with disease severity, suggesting increased energy needs later in the disease process, and elevated urinary mevalonate levels. PMID:23891537

Williams, Sarah; Gregory, Allison; Hogarth, Penelope; Hayflick, Susan J; Gillingham, Melanie B

2013-07-01

221

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

PubMed Central

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.

Sanders, Robert W.; Porter, Karen G.

1986-01-01

222

Perturbed Energy Metabolism and Neuronal Circuit Dysfunction in Cognitive Impairment  

PubMed Central

Summary Epidemiological, neuropathological and functional neuroimaging evidence implicates global and regional derangements in brain metabolism and energetics in the pathogenesis of cognitive impairment. Nerve cell microcircuits are modified adaptively by excitatory and inhibitory synaptic activity and neurotrophic factors. Aging and Alzheimer’s disease (AD) cause perturbations in cellular energy metabolism, level of excitation/inhibition and neurotrophic factor release that overwhelm compensatory mechanisms and result in neuronal microcircuit and brain network dysfunction. A prolonged positive energy balance impairs the ability of neurons to respond adaptively to oxidative and metabolic stress. Experimental studies in animals demonstrate how derangements related to chronic positive energy balance, such as diabetes, set the stage for accelerated cognitive aging and AD. Therapeutic interventions to allay cognitive dysfunction that target energy metabolism and adaptive stress responses (such as neurotrophin signaling) have shown efficacy in animal models and preliminary studies in humans.

Kapogiannis, Dimitrios; Mattson, Mark P.

2010-01-01

223

Metabolic Strategies in Energy-Limited Microbial Communities in the Anoxic Subsurface (Frasassi Cave System, Italy)  

NASA Astrophysics Data System (ADS)

Two major sources of energy, light and chemical potential, are available to microorganisms. However, energy is not always abundant and is often a limiting factor in microbial survival and replication. The anoxic, terrestrial subsurface offers a unique opportunity to study microorganisms and their potentially novel metabolic strategies that are relevant for understanding biogeochemistry and biosignatures as related to the non-photosynthetic, energy-limited environments on the modern and ancient Earth and elsewhere in the solar system. Geochemical data collected in a remote stratified lake 600 m below ground surface in the sulfidic Frasassi cave system (Italy) suggest that little redox energy is available for life, consistent with low signal from domain-specific FISH probes. The carbon isotope signatures of biofilms (-33‰) and DIC (-9‰) in the anoxic water suggest in situ production by lithoautotrophs using RuBisCO. 16S rDNA libraries constructed from the biofilm are dominated by diverse sulfate reducing bacteria. The remaining bacterial and archaeal clones affiliate with more than 11 major uncultivated or novel prokaryotic lineages. Diverse dsrAB gene sequences are consistent with high sulfate concentrations and undetectable or extremely low oxygen, nitrate, and iron concentrations. However, the electron donor for sulfate reduction is unclear. Methane is detectable in the anoxic water although no 16S rDNA sequences associated with known methanogens or anaerobic methane oxidizers were retrieved. mcrA gene sequences retrieved from the biofilm by cloning are not related to cultivated methanogens or to known anaerobic methane oxidizers. Non-purgable organic carbon (NPOC) is below detection limits (i.e. <42 ?M acetate) suggesting that alternative electron donors or novel metabolisms may be important. A sample collected by cave divers in October 2009 was pyrosequenced at the Pennsylvania State University Genomics Core Facility using Titanium chemistry (454 Life Sciences). We retrieved more than 420,000 metagenomic reads, of which 46% have significant homology to sequences in NCBI’s non-redundant protein database and 3% could be assigned using the Clusters of Orthologous Groups of proteins (COGs) classification system. 16S (174 reads) and 23S (283 reads) rDNA sequences in the metagenome imply a phylogenetically diverse community dominated by Deltaproteobacteria and Firmicutes. We also identified 15 metagenome sequences with homology to known dsrAB genes. Further work will identify additional genes for specific energy and nutrient metabolisms in the community, as well as use comparative analyses to determine overrepresented functions that are characteristic of life in the oligotrophic, euxinic cave environment.

McCauley, R. L.; Jones, D. S.; Schaperdoth, I.; Steinberg, L.; Macalady, J. L.

2010-12-01

224

Energy metabolism of the developing brain  

SciTech Connect

Cerebral metabolism in utero and in the neonatal period remains incompletely understood. A major investigative technique uses /sup 14/C deoxyglucose. Species differences, behavioral states and gestational age all have an impact. Hormonal and sensory stimuli have potential influences. The use of this new investigative technique in the human will allow detailed study of the effects of a variety of pathophysiologic events and possibly of drug therapy on cerebral glucose metabolism.

Abrams, R.M.; Hutchison, A.A.

1985-04-01

225

Regulation of protein and energy metabolism by the somatotropic axis  

Microsoft Academic Search

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

B. H Breier

1999-01-01

226

ANAEROBIC COMPOSTING FOR RECOVERY OF NUTRIENTS, COMPOST, AND ENERGY FROM SOLID WASTES DURING SPACE  

Microsoft Academic Search

1. ABSTRACT The technical feasibility of applying,leachbed,high-solids anaerobic,digestion for reduction and stabilization of the organic fraction of solid ,wastes generated ,during space missions ,was ,investigated. This process has the advantages of not requiring oxygen or high temperature and pressure while producing methane, carbon dioxide, nutrients, and compost as valuable products. Anaerobic biochemical methane potential assays run on several waste feedstocks

David Chynoweth; Patrick Haley; John Owens; Art Teixeira; Tim Townsend; Qiyong Xu; Hong-Lim Choi

227

Metabolic and genetic regulation of cardiac energy substrate preference  

Microsoft Academic Search

Proper heart function relies on high efficiency of energy conversion. Mitochondrial oxygen-dependent processes transfer most of the chemical energy from metabolic substrates into ATP. Healthy myocardium uses mainly fatty acids as its major energy source, with little contribution of glucose. However, lactate, ketone bodies, amino acids or even acetate can be oxidized under certain circumstances. A complex interplay exists between

Izaäk Frederik Kodde; Johan van der Stok; Ryszard T. Smolenski; Jan Willem de Jong

2007-01-01

228

One-carbon metabolism in anaerobes: Organic acid and methane production: Final technical report for period June 1, 1985-May 31,1987  

SciTech Connect

Objectives of this project dealt with understanding one- and multicarbon metabolism in acetogenic and methanogenic bacteria. The biochemistry of acetate catabolism in Methanosarcina barkeri in relation to their major enzyme activities, co-factors and intermediates were studied. The physiological function of CO-dehydrogenase was investigated and found to be involved in hydrogen production when CO was used as substrate. Hydrogen metabolism from acetate by Methanosarcina barkeri was investigated through isotope tracer studies. Results showed that hydrogen production appears to be linked to several intracellular redox processes which follow the cleavage of acetate. The metabolic pathway in Butyribacterium methylotrophicum for multicarbon metabolism was elucidated. The key enzyme, ferredoxin-NAD reductase, was found to be regulated by NADH. The one carbon and multicarbon metabolic pathways in Butyribacterium methylotrophicum were constituted. Hydrogen was produced through multicarbon metabolism and was consumed by one carbon metabolism through the reduction of CO/sub 2/. Results revealed why high efficiency of carbon and energy conservation was observed in acetogens. The catabolism of formate to acetate by this microorganism was analyzed by fermentation time course and /sup 13/C nuclear magnetic resonance studies. Results indicate a bifurcated single-carbon catabolic pathway in which CO/sub 2/ is the sole single-carbon compound that directly supplies the carbonyl and methyl group synthesis pathways leading to the formation of acetyl coenzyme A, the primary reduced product. 1 fig.

Zeikus, J.G.

1987-10-01

229

Sex differences in substrate metabolism and energy homeostasis.  

PubMed

Females differ remarkably from males in the mechanisms that regulate substrate utilization and energy homeostasis. Females appear to be less affected in terms of growth and loss of body tissues when subjected to chronic periods of negative energy balance. The physiological trade-off appears to be a stronger propensity toward retention of fat mass during times of energy surfeit. The mechanism(s) that account for sex differences in energy metabolism are not known but most likely involve the sex steroids. Recent discoveries in the areas of endocrinology and metabolism may provide new insights into differences in the control of food intake and energy conservation between the sexes. Finally, the study of the mechanism(s) involved in the regulation of skeletal muscle lipid metabolism represents a new frontier in skeletal muscle bioenergetics, and new discoveries may provide further explanations for the observed sex differences in substrate utilization and response(s) to alterations in energy homeostasis. PMID:10953067

Cortright, R N; Koves, T R

2000-08-01

230

Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus?†  

PubMed Central

Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]benzene to [14C]carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism, and [14C]benzoate was produced from [14C]benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not upregulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- than in benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much-needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms.

Holmes, Dawn E.; Risso, Carla; Smith, Jessica A.; Lovley, Derek R.

2011-01-01

231

Anaerobic oxidation of benzene by the hyperthermophilic archaeon Ferroglobus placidus.  

PubMed

Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [(14)C]benzene to [(14)C]carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism, and [(14)C]benzoate was produced from [(14)C]benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not upregulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- than in benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much-needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms. PMID:21742914

Holmes, Dawn E; Risso, Carla; Smith, Jessica A; Lovley, Derek R

2011-07-08

232

Energetic metabolism of Chromobacterium violaceum.  

PubMed

Chromobacterium violaceum is a free-living microorganism, normally exposed to diverse environmental conditions; it has a versatile energy-generating metabolism. This bacterium is capable of exploiting a wide range of energy resources by using appropriate oxidases and reductases. This allows C. violaceum to live in both aerobic and anaerobic conditions. In aerobic conditions, C. violaceum is able to grow in a minimal medium with simple sugars, such as glucose, fructose, galactose, and ribose; both Embden-Meyerhoff, tricarboxylic acid and glyoxylate cycles are used. The respiratory chain supplies energy, as well as substrates for other metabolic pathways. Under anaerobic conditions, C. violaceum metabolizes glucose, producing acetic and formic acid, but not lactic acid or ethanol. C. violaceum is also able to use amino acids and lipids as an energy supply. PMID:15100996

Creczynski-Pasa, Tânia B; Antônio, Regina V

2004-03-31

233

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

Microsoft Academic Search

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

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

234

Standard anaerobic exercise tests.  

PubMed

Anaerobic tests are divided into tests measuring anaerobic power and anaerobic capacity. Anaerobic power tests include force-velocity tests, vertical jump tests, staircase tests, and cycle ergometer tests. The values of maximal anaerobic power obtained with these different protocols are different but generally well correlated. Differences between tests include factors such as whether average power or instantaneous power is measured, active muscle mass is the same in all the protocols, the legs act simultaneously or successively, maximal power is measured at the very beginning of exercise or after several seconds, inertia of the devices and body segments are taken into account. Force-velocity tests have the advantage of enabling the estimation of the force and velocity components of power, which is not possible with tests such as a staircase test, a vertical jump, the Wingate test and other long-duration cycle ergometer protocols. Maximal anaerobic capacity tests are subdivided into maximal oxygen debt test, ergometric tests (all-out tests and constant load tests), measurement of oxygen deficit during a constant load test and measurement of peak blood lactate. The measurement of the maximal oxygen debt is not valid and reliable enough to be used as an anaerobic capacity test. The aerobic metabolism involvement during anaerobic capacity tests, and the ignorance of the mechanical efficiency, limit the validity of the ergometric tests which are only based on the measurement of work. The amount of work performed during the Wingate test depends probably on glycolytic and aerobic power as well as anaerobic capacity. The fatigue index (power decrease) of the all-out tests is not reliable and depends probably on aerobic power as well as the fast-twich fibre percentage. Reliability of the constant load tests has seldom been studied and has been found to be rather low. In theory, the measure of the oxygen deficit during a constant load test is more valid than the other tests but its reliability is unknown. The validity and reliability of postexercise blood lactate as a test of maximal anaerobic capacity are probably not better than that of the current erogmetric tests. The choice of an anaerobic test depends on the aims and subjects of a study and its practicability within a testing session. PMID:3306867

Vandewalle, H; Pérès, G; Monod, H

235

Energetics of end product excretion in anaerobic bacteria and the metabolism of fatty acids by Syntrophomonas wolfei: Progress report, March 15, 1985--June 30, 1988  

SciTech Connect

We developed methods to physically separate cells of the anaerobic, fatty acid degrade, Syntrophomonas wolfei, from cells of the hydrogen user by Percoll gradient centrifugation and to selectively lyse S. wolfei cells using lysozyme. These methods allowed the study of the physiology of S. wolfei without significant contamination. Fatty acids were degraded by the B-oxidation pathway using a coenzyme A (CoA) transferase activity to activate the fatty acid and substrate- level phosphorylation reactions to synthesize. The substrate specificity of the CoA transferase activity in the pure culture of S. wolfei differed from that found in the coculture suggesting that the ability to use crotonate resulted from an alteration of this enzyme. S. wolfei grown alone degraded crotonate in a manner similar to that of other crotonate-fermenting anaerobes, but the molar growth yields of S. wolfei were 2 to 3 times higher than those organisms. This suggests that the reduction of crotonyl-CoA to butyryl-CoA is energy yielding. S. wolfei contained a c-type cytochrome which may be involved in this reaction. S. wolfei synthesized large amounts of the storage polymer, poly-B-hydroxybutyrate.

McInerney, M.J.

1988-01-01

236

Inborn Errors of Energy Metabolism Associated with Myopathies  

PubMed Central

Inherited neuromuscular disorders affect approximately one in 3,500 children. Structural muscular defects are most common; however functional impairment of skeletal and cardiac muscle in both children and adults may be caused by inborn errors of energy metabolism as well. Patients suffering from metabolic myopathies due to compromised energy metabolism may present with exercise intolerance, muscle pain, reversible or progressive muscle weakness, and myoglobinuria. In this review, the physiology of energy metabolism in muscle is described, followed by the presentation of distinct disorders affecting skeletal and cardiac muscle: glycogen storage diseases types III, V, VII, fatty acid oxidation defects, and respiratory chain defects (i.e., mitochondriopathies). The diagnostic work-up and therapeutic options in these disorders are discussed.

Das, Anibh M.; Steuerwald, Ulrike; Illsinger, Sabine

2010-01-01

237

Energy metabolism and energy-sensing pathways in mammalian embryonic and adult stem cell fate.  

PubMed

Metabolism is influenced by age, food intake, and conditions such as diabetes and obesity. How do physiological or pathological metabolic changes influence stem cells, which are crucial for tissue homeostasis? This Commentary reviews recent evidence that stem cells have different metabolic demands than differentiated cells, and that the molecular mechanisms that control stem cell self-renewal and differentiation are functionally connected to the metabolic state of the cell and the surrounding stem cell niche. Furthermore, we present how energy-sensing signaling molecules and metabolism regulators are implicated in the regulation of stem cell self-renewal and differentiation. Finally, we discuss the emerging literature on the metabolism of induced pluripotent stem cells and how manipulating metabolic pathways might aid cellular reprogramming. Determining how energy metabolism regulates stem cell fate should shed light on the decline in tissue regeneration that occurs during aging and facilitate the development of therapies for degenerative or metabolic diseases. PMID:23420198

Rafalski, Victoria A; Mancini, Elena; Brunet, Anne

2012-12-01

238

Metabolism of Reduced Methylated Sulfur Compounds in Anaerobic Sediments and by a Pure Culture of an Estuarine Methanogen †  

PubMed Central

Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated methane production. The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments. Production of methane from these reduced methylated sulfur compounds was blocked by 2-bromoethanesulfonic acid. Sulfate did not influence the metabolism of millimolar levels of DMS, DMDS, or MSH added to sediments. However, when DMS was added at ?2-?M levels as [14C]DMS, metabolism by sediments resulted in a 14CH4/14CO2 ratio of only 0.06. Addition of molybdate increased the ratio to 1.8, while 2-bromoethanesulfonic acid decreased it to 0, but did not block 14CO2 production. These results indicate the methanogens and sulfate reducers compete for DMS when it is present at low concentrations; however, at high concentrations, DMS is a “noncompetitive” substrate for methanogens. Metabolism of DMS by sediments resulted in the appearance of MSH as a transient intermediate. A pure culture of an obligately methylotrophic estuarine methanogen was isolated which was capable of growth on DMS. Metabolism of DMS by the culture also resulted in the transient appearance of MSH, but the organism could grow on neither MSH nor DMDS. The culture metabolized [14C]-DMS to yield a 14CH4/14CO2 ratio of ?2.8. Reduced methylated sulfur compounds represent a new class of substrates for methanogens and may be potential precursors of methane in a variety of aquatic habitats.

Kiene, Ronald P.; Oremland, Ronald S.; Catena, Anthony; Miller, Laurence G.; Capone, Douglas G.

1986-01-01

239

Energy efficacy used to score organic refuse pretreatment processes for hydrogen anaerobic production.  

PubMed

The production of hydrogen through Anaerobic Digestion (AD) has been investigated to verify the efficacy of several pretreatment processes. Three types of waste with different carbon structures have been tested to obtain an extensive representation of the behavior of the materials present in Organic Waste (OW). The following types of waste were selected: Sweet Product Residue (SPR), i.e., confectionary residue removed from the market after the expiration date, Organic Waste Market (OWM) refuse from a local fruit and vegetable market, and Coffee Seed Skin (CSS) waste from a coffee production plant. Several pretreatment processes have been applied, including physical, chemical, thermal, and ultrasonic processes and a combination of these processes. Two methods have been used for the SPR to remove the packaging, manual (SPR) and mechanical (SPRex). A pilot plant that is able to extrude the refuse to 200atm was utilized. Two parameters have been used to score the different pretreatment processes: efficiency (?), which takes into account the amount of energy produced in the form of hydrogen compared with the available energy embedded in the refuse, and efficacy (?), which compares the efficiency obtained using the pretreated refuse with that obtained using the untreated refuse. The best result obtained for the SPR was the basic pretreatment, with ?=6.4, whereas the thermal basic pretreatment gave the highest value, ?=17.0 for SPRex. The best result for the OWM was obtained through a combination of basic/thermal pretreatments with ?=9.9; lastly, the CSS residue with ultrasonic pretreatment produced the highest quantity of hydrogen, ?=5.2. PMID:23891078

Ruggeri, Bernardo; Luongo Malave, Andrea C; Bernardi, Milena; Fino, Debora

2013-07-23

240

Effects of deep freezing on the energy metabolism of bovine spermatozoa during in vitro capacitation: A cytochemical approach.  

PubMed

In order to study the effects of deep freezing on the energy metabolism of bovine spermatozoa, a cytochemical quantitative study was carried out by a microdensitometric method on cytochrome oxidase and lactate dehydrogenase (LDH) activities. These were evaluated in situ on individual frozen-thawed bull spermatozoa collected at different times during in vitro capacitation. The results showed that in bull spermatozoa both the initiation of motility and capacity to fertilize eggs were associated with the anaerobic rather than aerobic glycolysis. The freezing-thawing processes and storage in liquid nitrogen induced a general enhancement of both the enzymatic activities examined. The high ionic strength treatment gave rise to a significant but reversible decrease in both the cytochrome oxidase and LDH activities in the fresh as well as in the frozen-stored sperm. The findings, based on cytochemical observations of energy metabolism of spermatozoa and evaluated during in vitro capacitation, suggest that the respiration and the anaerobic glycolysis of spermatozoa seem to be slightly impaired by the freezing-thawing and storage processes. PMID:16726499

Ferrandi, B; Lange Consiglio, A; Cremonesi, F; Carnevali, A; Porcelli, F

1988-09-01

241

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

PubMed Central

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.

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

2000-01-01

242

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi  

Microsoft Academic Search

Detailed physiological studies were done to compare the influence of environmental pH and fermentation end product formation on metabolism, growth, and proton motive force in Sarcina ventriculi. The kinetics of end product formation during glucose fermentation in unbuffered batch cultures shifted from hydrogen-acetate production to ethanol production as the medium pH dropped from 7.0 to 3.3. At a constant pH

S. Goodwin; J. G. Zeikus

1987-01-01

243

Metabolic and genetic regulation of cardiac energy substrate preference.  

PubMed

Proper heart function relies on high efficiency of energy conversion. Mitochondrial oxygen-dependent processes transfer most of the chemical energy from metabolic substrates into ATP. Healthy myocardium uses mainly fatty acids as its major energy source, with little contribution of glucose. However, lactate, ketone bodies, amino acids or even acetate can be oxidized under certain circumstances. A complex interplay exists between various substrates responding to energy needs and substrate availability. The relative substrate concentration is the prime factor defining preference and utilization rate. Allosteric enzyme regulation and protein phosphorylation cascades, partially controlled by hormones such as insulin, modulate the concentration effect; together they provide short-term adjustments of cardiac energy metabolism. The expression of metabolic machinery genes is also dynamically regulated in response to developmental and (patho)physiological conditions, leading to long-term adjustments. Specific nuclear receptor transcription factors and co-activators regulate the expression of these genes. These include peroxisome proliferator-activated receptors and their nuclear receptor co-activator, estrogen-related receptor and hypoxia-inducible transcription factor 1. Increasing glucose and reducing fatty acid oxidation by metabolic regulation is already a target for effective drugs used in ischemic heart disease and heart failure. Interaction with genetic factors that control energy metabolism could provide even more powerful pharmacological tools. PMID:17081788

Kodde, Izaäk Frederik; van der Stok, Johan; Smolenski, Ryszard T; de Jong, Jan Willem

2006-10-03

244

Temperature and pH dependence of energy balance by 31P- and 1H-MRS in anaerobic frog muscle  

Microsoft Academic Search

The temperature (T)-dependence of energy consumption of resting anaerobic frog gastrocnemii exposed to different, changing electrochemical gradients was assessed. To this aim, the rate of ATP resynthesis (??P\\/?t) was determined by 31P- and 1H-MRS as the sum of the rates of PCr hydrolysis (?[PCr]\\/?t) and of anaerobic glycolysis (?[La]\\/ ?t, based on a ?P\\/La ratio of 1.5). The investigated T levels

Alessandra Vezzoli; Maristella Gussoni; Fulvia Greco; Lucia Zetta; Paolo Cerretelli

2004-01-01

245

Membrane controlled anaerobic digestion  

NASA Astrophysics Data System (ADS)

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.

Omstead, D. R.

246

The energy metabolism of the adult common liver fluke, Fasciola hepatica  

Microsoft Academic Search

In adultFasciola hepatica glucose is broken down to volatile fatty acids, carbon dioxide and lactate. In the cytosol glucose is converted into malate and lactate and malate is metabolized further in the mitochondrial compartment via a dismutation. The dismutation of malate can proceed under anaerobic conditions. To a limited extent oxygen can function as terminal electron acceptor.It is shown that

F. van Vugt

1979-01-01

247

Flexibility in energy metabolism supports hypoxia tolerance in Drosophila flight muscle: metabolomic and computational systems analysis  

Microsoft Academic Search

The fruitfly Drosophila melanogaster offers promise as a genetically tractable model for studying adaptation to hypoxia at the cellular level, but the metabolic basis for extreme hypoxia tolerance in flies is not well known. Using 1H NMR spectroscopy, metabolomic profiles were collected under hypoxia. Accumulation of lactate, alanine, and acetate suggested that these are the major end products of anaerobic

Jacob D Feala; Laurence Coquin; Andrew D McCulloch; Giovanni Paternostro

2007-01-01

248

MYC-induced Cancer Cell Energy Metabolism and Therapeutic Opportunities  

PubMed Central

Although cancers have altered glucose metabolism, termed the Warburg effect that describes the increased uptake and conversion of glucose to lactate by cancer cells under adequate oxygen tension, changes in the metabolism of glutamine and fatty acid have also been documented. The MYC oncogene, which contributes to the genesis of many human cancers, encodes a transcription factor, c-Myc, that links altered cellular metabolism to tumorigenesis. c-Myc regulates genes involved in the biogenesis of ribosomes and mitochondria, and regulation of glucose and glutamine metabolism. With E2F1, c-Myc induces genes involved in nucleotide metabolism and DNA replication, and microRNAs that homeostatically attenuate E2F1 expression. With the hypoxia inducible transcription factor HIF-1, ectopic c-Myc cooperatively induces a transcriptional program for hypoxic adaptation. Myc regulates gene expression either directly, such as glycolytic genes including lactate dehydrogenase A (LDHA), or indirectly, such as repression of microRNAs miR-23a/b to increase glutaminase (GLS) protein expression and glutamine metabolism. Ectopic MYC expression in cancers, therefore, could concurrently drive aerobic glycolysis and/or oxidative phosphorylation to provide sufficient energy and anabolic substrates for cell growth and proliferation in the context of the tumor microenvironment. Collectively, these studies indicate that Myc-mediated altered cancer cell energy metabolism could be translated for the development of new anti-cancer therapies.

Dang, Chi V.; Le, Anne; Gao, Ping

2009-01-01

249

Use of fixed-film, anaerobic bioreactors for energy-conserving treatment of meatpacking wastewaters  

SciTech Connect

A new wastewater treatment process based on the anaerobic approach has been developed at Oak Ridge National Laboratory. This treatment process is based on a packed-bed reactor to which anaerobic microorganisms have been added. An attempt was made to determine experimentally if waste waters from a meatpacking plant could be treated in a laboratory-scale ANFLOW (anaerobic upflow) bioreactor. This included evaluating a packing material for use in the bioreactor, demonstrating the development of fixed films in the bioreactors, and determining the times required for system start-up. The performance of the bioreactor in removing carbon from the waste waters and in producing methane as a by-product is evaluated. (MHR)

Dinsmore, T.V.

1981-11-01

250

Central role of ceramide biosynthesis in body weight regulation, energy metabolism, and the metabolic syndrome  

PubMed Central

Although obesity is associated with multiple features of the metabolic syndrome (insulin resistance, leptin resistance, hepatic steatosis, chronic inflammation, etc.), the molecular changes that promote these conditions are not completely understood. Here, we tested the hypothesis that elevated ceramide biosynthesis contributes to the pathogenesis of obesity and the metabolic syndrome. Chronic treatment for 8 wk of genetically obese (ob/ob), and, high-fat diet-induced obese (DIO) mice with myriocin, an inhibitor of de novo ceramide synthesis, decreased circulating ceramides. Decreased ceramide was associated with reduced weight, enhanced metabolism and energy expenditure, decreased hepatic steatosis, and improved glucose hemostasis via enhancement of insulin signaling in the liver and muscle. Inhibition of de novo ceramide biosynthesis decreased adipose expression of suppressor of cytokine signaling-3 (SOCS-3) and induced adipose uncoupling protein-3 (UCP3). Moreover, ceramide directly induced SOCS-3 and inhibited UCP3 mRNA in cultured adipocytes suggesting a direct role for ceramide in regulation of metabolism and energy expenditure. Inhibition of de novo ceramide synthesis had no effect on adipose tumor necrosis factor-? (TNF-?) expression but dramatically reduced adipose plasminogen activator inhibitor-1 (PAI-1) and monocyte chemoattactant protein-1 (MCP-1). This study highlights a novel role for ceramide biosynthesis in body weight regulation, energy expenditure, and the metabolic syndrome.

Yang, Guang; Badeanlou, Leylla; Bielawski, Jacek; Roberts, Amanda J.; Hannun, Yusuf A.; Samad, Fahumiya

2009-01-01

251

Anaerobic co-metabolic oxidation of 4-alkylphenols with medium-length or long alkyl chains by Thauera sp., strain R5.  

PubMed

A 4-alkylphenol-degrading facultative anaerobic bacterium, strain R5, was isolated from paddy soil after enrichment with 4-n-propylphenol, 4-n-butylphenol and 4-hydroxybenzoate (4-HBA) under nitrate-reducing conditions. Strain R5 is a Gram-negative rod bacillus grown on phenolic compounds with short alkyl chains (metabolically transforms alkylphenols to the corresponding metabolites with oxidised alpha carbon in the alkyl chain during coupling with nitrate reduction. PMID:17387471

Shibata, Atsushi; Katayama, Arata

2007-03-27

252

Bibliography on anaerobic digestion  

SciTech Connect

The priority assigned to biogas systems by participants in A.I.D's Energy for Rural Development Program spurred the compilation of this 373-item bibliography on anaerobic digestion. The materials focus on energy technologies that are especially suited to the social, economic, and institutional concerns of rural Asia and the Pacific. Entries are presented in two sections. The first presents largely non-technical reports on anaerobic digesters in South and Southeast Asia, for the years 1956-80, with emphasis on the period 1970-80. The second section, which includes both technical and non-technical references, is a condensation of a computerized search of the U.S. Department of Energy's Energy Research Abstracts published during the period 1977-80. The search revealed a lack of reliable data, pointing to the need for further research on the technology and potential of anaerobic digestion.

Ramakrishna, J.; Pruett, D.M.; Santerre, M.T.; Toyoshiba, T.S.

1980-09-01

253

The generation of metabolic energy by solute transport  

Microsoft Academic Search

Secondary metabolic-energy-generating systems generate a proton motive force (pmf) or a sodium ion motive force (smf) by a\\u000a process that involves the action of secondary transporters. The (electro)chemical gradient of the solute(s) is converted into\\u000a the electrochemical gradient of protons or sodium ions. The most straightforward systems are the excretion systems by which\\u000a a metabolic end product is excreted out

Wil N. Konings; Juke S. Lolkema; Bert Poolman

1995-01-01

254

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

PubMed Central

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.

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; Methe, Barbara A

2009-01-01

255

Aerobic and anaerobic metabolism of 6,10,14-trimethylpentadecan-2-one by a denitrifying bacterium isolated from marine sediments.  

PubMed Central

This report describes the metabolism of 6,10,14-trimethylpentadecan-2-one by a denitrifying bacterium (Marinobacter sp. strain CAB) isolated from marine sediments. Under aerobic and denitrifying conditions, this strain efficiently degraded this ubiquitous isoprenoid ketone. Several bacterial metabolites, 4,8,12-trimethyl-tridecan-1-ol, 4,8,12-trimethyltridecanal, 4,8,12-trimethyltridecanoic acid, Z-3,7-dimethylocten-2-oic acid, Z-3,7,11-trimethyldodecen-2-oic acid, and 6,10,14-trimethylpentadecan-2-ol, were formally identified, and different pathways were proposed to explain the formation of such isoprenoid compounds.

Rontani, J F; Gilewicz, M J; Michotey, V D; Zheng, T L; Bonin, P C; Bertrand, J C

1997-01-01

256

What can metabolic myopathies teach us about exercise physiology?  

Microsoft Academic Search

Exercise physiologists are interested in metabolic myopathies because they demonstrate how knocking out a component of a specific biochemical pathway can alter cellular metabolism. McArdle's disease (myophosphorylase de- ficiency) has often been studied in exercise physiology to demonstrate the influence of removing the major anaerobic energy supply to skeletal muscle. Studies of patients with McArdle's disease have shown the increased

Mark A. Tarnopolsky

2006-01-01

257

One carbon metabolism in anaerobic bacteria. Organic acid and methane production. Progress report, June 1985-May 1986  

SciTech Connect

Our project focussed on understanding of one and multicarbon metabolism in acetogenic and methanogenic bacteria. The studies with acetate catabolism pathway in Methanosarcina barkeri showed involvement of methyl reductase, methyl coenzyme M and carbon monoxide dehydrogenase in the proposed model of acetate catabolism. We also examined the relationship between hydrogen metabolism and methanogenesis, isotopic discrimination during methanogenesis, and sulfate dependent interspecies H/sub 2/-transfer between M. barkeri and Desulfovibrio vulgaris. Ammonia assimilation in Methanobacterium ivanovii via glutamine synthetase (GS) was confirmed by isolation of GS-deficient and GS-impared auxotrophic mutants. GS from M. ivanovii is also purified, characterized and compared with the eubacterial GS. In Butyribacterium methylotrophicum various enzymes involved in homoacetogenic catabolism of formate, formate plus CO and methanol plus CO were examined. Carbon dioxide was shown to be a required intermediate during catabolism of CO by B. methylotrophicum. Studies were also conducted for the operation of electron transport phosphorylation (ETP) in B. methylotrophicum by analyzing the proton motive force (PMF) and membrane bound electron carriers. 13 refs.

Zeikus, J.G.

1986-05-01

258

Myocardial energy metabolism in ischemic preconditioning and cardioplegia: A metabolic control analysis  

Microsoft Academic Search

For both, cardioplegia (CP) and ischemic preconditioning (IP), increased ischemic tolerance with reduction in infarct size is well documented. These cardioprotective effects are related to a limitation of high energy phosphate (HEP) depletion. As CP and IP have to be assumed to act by different mechanisms, their effects on myocardial HEP metabolism cannot be assumed to be identical. Therefore, a

Achim M. Vogt; Albrecht Elsässer; Anja Pott-Beckert; Cordula Ackermann; Sven Y. Vetter; Murat Yildiz; Wolfgang Schoels; David A. Fell; Hugo A. Katus; Wolfgang Kübler

2005-01-01

259

Evolution of energy metabolism and its compartmentation in Kinetoplastida  

PubMed Central

Kinetoplastida are protozoan organisms that probably diverged early in evolution from other eukaryotes. They are characterized by a number of unique features with respect to their energy and carbohydrate metabolism. These organisms possess peculiar peroxisomes, called glycosomes, which play a central role in this metabolism; the organelles harbour enzymes of several catabolic and anabolic routes, including major parts of the glycolytic and pentosephosphate pathways. The kinetoplastid mitochondrion is also unusual with regard to both its structural and functional properties. In this review, we describe the unique compartmentation of metabolism in Kinetoplastida and the metabolic properties resulting from this compartmentation. We discuss the evidence for our recently proposed hypothesis that a common ancestor of Kinetoplastida and Euglenida acquired a photosynthetic alga as an endosymbiont, contrary to the earlier notion that this event occurred at a later stage of evolution, in the Euglenida lineage alone. The endosymbiont was subsequently lost from the kinetoplastid lineage but, during that process, some of its pathways of energy and carbohydrate metabolism were sequestered in the kinetoplastid peroxisomes, which consequently became glycosomes. The evolution of the kinetoplastid glycosomes and the possible selective advantages of these organelles for Kinetoplastida are discussed. We propose that the possession of glycosomes provided metabolic flexibility that has been important for the organisms to adapt easily to changing environmental conditions. It is likely that metabolic flexibility has been an important selective advantage for many kinetoplastid species during their evolution into the highly successful parasites today found in many divergent taxonomic groups. Also addressed is the evolution of the kinetoplastid mitochondrion, from a supposedly pluripotent organelle, attributed to a single endosymbiotic event that resulted in all mitochondria and hydrogenosomes of extant eukaryotes. Furthermore, indications are presented that Kinetoplastida may have acquired other enzymes of energy and carbohydrate metabolism by various lateral gene transfer events different from those that involved the algal- and ?-proteobacterial-like endosymbionts responsible for the respective formation of the glycosomes and mitochondria.

Hannaert, Veronique; Bringaud, Frederic; Opperdoes, Fred R; Michels, Paul AM

2003-01-01

260

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...

261

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

PubMed Central

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.

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

2013-01-01

262

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...

263

Test/QA Plan For Verification Of Anaerobic Digester For Energy Production And Pollution Prevention  

EPA Science Inventory

The ETV-ESTE Program conducts third-party verification testing of commercially available technologies that improve the environmental conditions in the U.S. A stakeholder committee of buyers and users of such technologies guided the development of this test on anaerobic digesters...

264

Two Routes of Metabolic Cross-Feeding between Bifidobacterium adolescentis and Butyrate-Producing Anaerobes from the Human Gut  

PubMed Central

Dietary carbohydrates have the potential to influence diverse functional groups of bacteria within the human large intestine. Of 12 Bifidobacterium strains of human gut origin from seven species tested, four grew in pure culture on starch and nine on fructo-oligosaccharides. The potential for metabolic cross-feeding between Bifidobacterium adolescentis and lactate-utilizing, butyrate-producing Firmicute bacteria related to Eubacterium hallii and Anaerostipes caccae was investigated in vitro. E. hallii L2-7 and A. caccae L1-92 failed to grow on starch in pure culture, but in coculture with B. adolescentis L2-32 butyrate was formed, indicating cross-feeding of metabolites to the lactate utilizers. Studies with [13C]lactate confirmed carbon flow from lactate, via acetyl coenzyme A, to butyrate both in pure cultures of E. hallii and in cocultures with B. adolescentis. Similar results were obtained in cocultures involving B. adolescentis DSM 20083 with fructo-oligosaccharides as the substrate. Butyrate formation was also stimulated, however, in cocultures of B. adolescentis L2-32 grown on starch or fructo-oligosaccharides with Roseburia sp. strain A2-183, which produces butyrate but does not utilize lactate. This is probably a consequence of the release by B. adolescentis of oligosaccharides that are available to Roseburia sp. strain A2-183. We conclude that two distinct mechanisms of metabolic cross-feeding between B. adolescentis and butyrate-forming bacteria may operate in gut ecosystems, one due to consumption of fermentation end products (lactate and acetate) and the other due to cross-feeding of partial breakdown products from complex substrates.

Belenguer, Alvaro; Duncan, Sylvia H.; Calder, A. Graham; Holtrop, Grietje; Louis, Petra; Lobley, Gerald E.; Flint, Harry J.

2006-01-01

265

Anaerobic mediastinitis.  

PubMed

Three patients with anaerobic mediastinitis associated with retropharyngeal abscess have been encountered recently. Dental infections accounted for two instances, and the third instance resulted from rupture of the thoracic esophagus from blunt trauma. Each was marked by extreme difficulty in achieving complete abscess drainage due to the initially unrecognized virulence of the causative anaerobic bacteria. Complications were frequent and included empyema, pericarditis and aspiration pneumonia. The combination of vigorous diagnostic efforts, prompt operation and reoperation when necessary plus specific antibiotic effective against anaerobes led to a successful outcome for each patient. PMID:959954

Howell, H S; Prinz, R A; Pickleman, J R

1976-09-01

266

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Biochemical methane potential decreased by 83% during the two-stage operation. Black-Right-Pointing-Pointer Net energy produced was 84.3 MWh or 46 kWh per million metric tons (Mg). Black-Right-Pointing-Pointer The average removal efficiency of volatile organic compounds (VOCs) was 96-99%. Black-Right-Pointing-Pointer The average removal efficiency of non-methane organic compounds (NMOCs) was 68-99%. Black-Right-Pointing-Pointer The two-stage batch digester proved to be simple to operate and cost-effective. - Abstract: The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3 MWh, or 46 kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.

Yazdani, Ramin, E-mail: ryazdani@sbcglobal.net [Yolo County Planning and Public Works Department, Division of Integrated Waste Management, Woodland, CA 95776 (United States); Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States); Barlaz, Morton A., E-mail: barlaz@eos.ncsu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Augenstein, Don, E-mail: iemdon@aol.com [Institute for Environmental Management, Inc., Palo Alto, CA 94306 (United States); Kayhanian, Masoud, E-mail: mdkayhanian@ucdavis.edu [Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States); Tchobanoglous, George, E-mail: gtchobanoglous@ucdavis.edu [Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States)

2012-05-15

267

Anaerobic-aerobic process for microbial degradation of tetrabromobisphenol A.  

PubMed

Tetrabromobisphenol A (TBBPA) is a flame retardant that is used as an additive during manufacturing of plastic polymers and electronic circuit boards. Little is known about the fate of this compound in the environment. In the current study we investigated biodegradation of TBBPA, as well as 2,4,6-tribromophenol (TBP), in slurry of anaerobic sediment from a wet ephemeral desert stream bed contaminated with chemical industry waste. Anaerobic incubation of the sediment with TBBPA and peptone-tryptone-glucose-yeast extract medium resulted in a 80% decrease in the TBBPA concentration and accumulation of a single metabolite. This metabolite was identified by gas chromatography-mass spectrometry (GC-MS) as nonbrominated bisphenol A (BPA). On the other hand, TBP was reductively dehalogenated to phenol, which was further metabolized under anaerobic conditions. BPA persisted in the anaerobic slurry but was degraded aerobically. A gram-negative bacterium (strain WH1) was isolated from the contaminated soil, and under aerobic conditions this organism could use BPA as a sole carbon and energy source. During degradation of BPA two metabolites were detected in the culture medium, and these metabolites were identified by GC-MS and high-performance liquid chromatography as 4-hydroxybenzoic acid and 4-hydroxyacetophenone. Both of those compounds were utilized by WH1 as carbon and energy sources. Our findings demonstrate that it may be possible to use a sequential anaerobic-aerobic process to completely degrade TBBPA in contaminated soils. PMID:10831413

Ronen, Z; Abeliovich, A

2000-06-01

268

Energy metabolism in adult neural stem cell fate.  

PubMed

The adult mammalian brain contains a population of neural stem cells that can give rise to neurons, astrocytes, and oligodendrocytes and are thought to be involved in certain forms of memory, behavior, and brain injury repair. Neural stem cell properties, such as self-renewal and multipotency, are modulated by both cell-intrinsic and cell-extrinsic factors. Emerging evidence suggests that energy metabolism is an important regulator of neural stem cell function. Molecules and signaling pathways that sense and influence energy metabolism, including insulin/insulin-like growth factor I (IGF-1)-FoxO and insulin/IGF-1-mTOR signaling, AMP-activated protein kinase (AMPK), SIRT1, and hypoxia-inducible factors, are now implicated in neural stem cell biology. Furthermore, these signaling modules are likely to cooperate with other pathways involved in stem cell maintenance and differentiation. This review summarizes the current understanding of how cellular and systemic energy metabolism regulate neural stem cell fate. The known consequences of dietary restriction, exercise, aging, and pathologies with deregulated energy metabolism for neural stem cells and their differentiated progeny will also be discussed. A better understanding of how neural stem cells are influenced by changes in energy availability will help unravel the complex nature of neural stem cell biology in both the normal and diseased state. PMID:21056618

Rafalski, Victoria A; Brunet, Anne

2010-11-05

269

Therapeutic Implications of Targeting Energy Metabolism in Breast Cancer  

PubMed Central

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.

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

2013-01-01

270

USE OF SOLAR ENERGY TO HEAT ANAEROBIC DIGESTERS. PART I. TECHNICAL AND ECONOMIC FEASIBILITY STUDY. PART II. ECONOMIC FEASIBILITY THROUGHOUT THE UNITED STATES  

EPA Science Inventory

Two distinct, yet related studies were conducted to determine the technical and economic feasibility of using solar energy as the source of heat for the anaerobic digestion process. Retrofitting a solar energy collection and heat transfer system to a digester at Annapolis, Maryla...

271

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi  

SciTech Connect

Detailed physiological studies were done to compare the influence of environmental pH and fermentation end product formation on metabolism, growth, and proton motive force in Sarcina ventriculi. The kinetics of end product formation during glucose fermentation in unbuffered batch cultures shifted from hydrogen-acetate production to ethanol production as the medium pH dropped from 7.0 to 3.3. At a constant pH of 3.0, the production of acetate ceased when the accumulation of acetate in the medium reached 40 mmol/liter. At a constant pH of 7.0, acetate production continued throughout the entire growth time course. The in vivo hydrogenase activity was much higher in cells grown at pH 7.0 than at pH 3.0. The magnitude of the proton motive force increased in relation to a decrease of the medium pH from 7.5 to 3.0. When the organism was grown at pH 3.0, the cytoplasmic pH was 4.25 and the organism was unable to exclude acetic acid or butyric acid from the cytoplasm. Addition of acetic acid, but not hydrogen or ethanol, inhibited growth and resulted in proton motive force dissipation and the accumulation of acetic acid in the cytoplasm. The results indicate that S. ventriculi is an acidophile that can continue to produce ethanol at low cytoplasmic pH values. Both the ability to shift to ethanol production and the ability to continue to ferment glucose while cytoplasmic pH values are low adapt S. ventriculi for growth at low pH.

Goodwin, S.; Zeikus, J.G.

1987-05-01

272

Anaerobic Treatment of Municipal Solid Waste and Sludge for Energy Production and Recycling of Nutrients  

NASA Astrophysics Data System (ADS)

This volume contains 18 papers presented at a Nordic workshop dealing with application of anaerobic decomposition processes on various types of organic wastes, held at the Siikasalmi Research and Experimental Station of the University of Joensuu on 1-2 Oct. 1992. Subject coverage of the presentations extends from the biochemical and microbiological principles of organic waste processing to descriptions and practical experiences of various types of treatment plants. The theoretical and experimental papers include studies on anaerobic and thermophilic degradation processes, methanogenesis, effects of hydrogen, treatment of chlorinated and phenolic compounds, and process modeling, while the practical examples range from treatment of various types of municipal, industrial, and mining wastes to agricultural and fish farm effluents. The papers provide technical descriptions of several biogas plants in operation. Geographically, the presentations span the Nordic and Baltic countries.

Leinonen, S.

273

Anaerobic digestion for global warming control and energy generation—An overview  

Microsoft Academic Search

Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon dioxide – which has been known to be a ‘clean’ fuel since the late 19th century. But a great resurgence of interest in biogas capture – hence methane capture – has occurred in recent years due to the rapidly growing spectre of global warming. Anthropogenic causes

Tasneem Abbasi; S. M. Tauseef; S. A. Abbasi

2012-01-01

274

Nodal regulates energy metabolism in glioma cells by inducing expression of hypoxia-inducible factor 1?.  

PubMed

Background A shift in glucose metabolism from oxidative phosphorylation to anaerobic glycolysis is the biochemical hallmark of malignant cancer cells. Methods In the present study, we demonstrated that Nodal stimulated the expression of glycolytic enzymes and decreased reliance on mitochondrial oxidative phosphorylation in human glioma cancer cells. The shift in glucose metabolism was mediated by induction of the hypoxia-inducible factor (HIF). Results Nodal protein expression was shown to be correlated with expression levels of glucose transporter (Glut)-1, hexokinase (HK)-II, pyruvate dehydrogenase kinase (PDK)-1, the phosphorylation level of pyruvate dehydrogenase (PDH), glucose uptake, and lactate accumulation in human glioma cells. These effects were inversely correlated with mitochondrial oxygen consumption and ATP production. Knockdown of Nodal expression with specific small hairpin RNA reduced Glut-1, HK-II, and PDK-1 expressions and PDH phosphorylation. Nodal knockdown also reduced glucose uptake and lactate generation, which in turn increased mitochondrial membrane potential (?), O2 utilization, and ATP synthesis. The ectopic expression of Nodal in low-expressing Nodal glioma cells resulted in the opposite results compared with those of Nodal knockdown glioma cells. Treatment of cells with recombinant Nodal increased HIF-1 expression, and this effect was regulated at the transcriptional level. Blockage of the Nodal receptor by a pharmacological inhibitor or Nodal knockdown in U87MG cells decreased HIF-1? expression. Furthermore, HIF-1? knockdown in U87MG cells decreased Glut-1, HK-II, and PDK-1 expressions and PDH phosphorylation, which were similar to results in Nodal knockdown cells. Conclusion Taken together, these results suggest that Nodal affects energy metabolism through HIF-1?. PMID:23911596

Lai, Jing-Huei; Jan, Hsun-Jin; Liu, Li-Wen; Lee, Chin-Cheng; Wang, Shyang-Guang; Hueng, Dueng-Yuan; Cheng, Yung-Yen; Lee, Horng-Mo; Ma, Hsin-I

2013-08-01

275

Genetic modulation of energy metabolism in birds through mitochondrial function  

PubMed Central

Despite their central importance for the evolution of physiological variation, the genetic mechanisms that determine energy expenditure in animals have largely remained unstudied. We used quantitative genetics to confirm that both mass-specific and whole-organism basal metabolic rate (BMR) were heritable in a captive-bred population of stonechats (Saxicola torquata spp.) founded on birds from three wild populations (Europe, Africa and Asia) that differed in BMR. This argues that BMR is at least partially under genetic control by multiple unknown nuclear loci each with a limited effect on the phenotype. We then tested for a genetic effect on BMR based on mitochondrial–nuclear coadaptation using hybrids between ancestral populations with high and low BMR (Europe–Africa and Asia–Europe), with different parental configurations (femalehigh–malelow or femalelow–malehigh) within each combination of populations. Hybrids with different parental configurations have on average identical mixtures of nuclear DNA, but differ in mitochondrial DNA because it is inherited only from the mother. Mass-specific BMR differed between hybrids with different parental configurations, implying that the combination of mitochondrial and nuclear DNA affected metabolic rate. Therefore, our findings implicate mitochondrial function as an important regulator of energy metabolism. In combination with the substantial heritabilities of metabolic rate, and corroborated by genetic differences in the mitochondrial genome, these results set the stage for further investigations of a genetic control mechanism involving both mitochondrial and nuclear genes determining metabolic rate at the whole-organism level.

Tieleman, B. Irene; Versteegh, Maaike A.; Fries, Anthony; Helm, Barbara; Dingemanse, Niels J.; Gibbs, H. Lisle; Williams, Joseph B.

2009-01-01

276

Chronic Sympathetic Attenuation and Energy Metabolism in Autonomic Failure  

PubMed Central

The sympathetic nervous system regulates thermogenesis and energy homeostasis in humans. When activated it increases energy expenditure, particularly resting energy expenditure. Most human studies used acute infusion of ?-blockers as a model to eliminate sympathetic stimulation and examine the contribution of the sympathetic nervous system to energy metabolism and balance. Clinically, however, it is also important to assess the effect of chronic sympathetic attenuation on energy metabolism. In this context, we hypothesized that resting energy expenditure is decreased in patients with autonomic failure who by definition have low sympathetic tone. We measured 24-hour energy expenditure using whole-room indirect calorimeter in 10 adults with chronic autonomic failure, (6 females; age 64.9±9.1 years; body mass index 25.2±4.4 kg/m2) and 15 sedentary healthy controls of similar age and body composition (8 females age 63.1±4.0 years; body mass index 24.4±3.9 kg/m2). In 4 patients, we eliminated residual sympathetic activity with the ganglionic blocker trimethaphan. We found that after adjusting for body composition, resting energy expenditure did not differ between patients with autonomic failure and healthy controls. However, resting energy expenditure significantly decreased when residual sympathetic activity was eliminated. Our findings suggest that sympathetic tonic support of resting energy expenditure is preserved, at least in part, in pathophysiological models of chronic sympathetic attenuation.

Shibao, Cyndya; Buchowski, Maciej S; Chen, Kong Y; Yu, Chang; Biaggioni, Italo

2012-01-01

277

On the kinetics of anaerobic power  

PubMed Central

Background This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises. Results Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, Model 2 showed that the alactic energy storage decreased with time, whereas Model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy. Conclusions The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicate that blood lactate levels can be accurately modeled during steady state, and suggests a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power.

2012-01-01

278

Urocortins: emerging metabolic and energy homeostasis perspectives  

Microsoft Academic Search

The effects of stress on energy balance and the involvement of the neuropeptide corticotropin releasing factor in modulating the anorexia of stress and sympath- etic nervous system tone are well recognized. Currently, studies centered on the roles of the more recently described members of this family of ligands, the urocor- tins, and their preferred receptor, the corticotropin releasing factor type

Yael Kuperman; Alon Chen

2008-01-01

279

Characteristics of energy metabolism in males with mental retardation.  

PubMed

To characterize the energy metabolism in individuals with mental retardation (MRs), we measured energy cost at several physical activity levels (basal, supine, sitting, standing, and walking at 30, 50 and 70 m/min), maximal oxygen consumption (Vo2max), and body composition in 23 male MRs and the same number of volunteer male controls. Both groups were individually matched for age, body height, and body weight. Energy cost was measured by the Douglas bag technique. The recently developed sulfur hexafluoride (SF6) dilution technique was employed for measuring body composition. In addition, 3-dimensional accelerometry was used for evaluating body movements, and plasma indices of macronutrients were also measured. The energy cost of MRs, when sitting, standing, and walking at 30 and 50 m/min, was significantly higher than that of controls (p < 0.05), while the basal and resting metabolic rates were similar in both groups. Vo2max was significantly lower (p < 0.05) in MRs than controls. Accelerometry demonstrated excessive movement by MRs, which may explain their higher energy cost of exercise. In contrast, no significant difference was observed in percent body fat or lean body mass. Concentrations of plasma total cholesterol, triacylglycerols and albumin were significantly lower in MRs as compared with the controls. Our findings suggest that MRs are burdened with an energy metabolism less economical than non-MRs. Limited physical activity in their daily life may be the cause. These characteristics of MRs' energy metabolism should be considered for planning their proper dietary schedules and physical activity programs. PMID:9591242

Iwaoka, H; Yokoyama, T; Masayasu, S; Fuchi, T; Nakayama, T; Tanaka, H

1998-02-01

280

Novel energy metabolism in anaerobic hyperthermophilic archaea: a modified Embden-Meyerhof pathway  

Microsoft Academic Search

Hyperthermophiles, a group of microorganisms whose optimum growth temperatures are above 80°C, have been isolated mainly from marine and continental volcanic environments. They are viewed as potential sources of extraordinarily stable biomolecules with applications in novel industrial processes. Most hyperthermophiles belong to the domain Archaea, the third domain of life, and are considered to be the most ancient of all

Haruhiko Sakuraba; Toshihisa Ohshima

2002-01-01

281

Anaerobic Digestion and Biocatalysis.  

National Technical Information Service (NTIS)

A report is given on the scope of the technical programmes in the UK and the US on anaerobic digestion and biocatalysis. The study arises from the Collaboration Agreement signed by the respective Secretaries of State for Energy in the UK and US in 1984. T...

1985-01-01

282

A Single Eubacterial Origin of Eukaryotic Pyruvate:Ferredoxin Oxidoreductase Genes: Implications for the Evolution of Anaerobic Eukaryotes  

Microsoft Academic Search

The iron sulfur protein pyruvate:ferredoxin oxidoreductase (PFO) is central to energy metabolism in amitochondriate eukaryotes, including those with hydrogenosomes. Thus, revealing the evolutionary history of PFO is critical to understanding the origin(s) of eukaryote anaerobic energy metabolism. We determined a complete PFO sequence for Spironucleus barkhanus, a large fragment of a PFO sequence from Clostridium pasteurianum,and a fragment of a

David S. Horner; Robert P. Hirt; T. Martin Embley

283

Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review  

NASA Astrophysics Data System (ADS)

Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

Hassan, Siti Roshayu; Dahlan, Irvan

2013-09-01

284

Effect of capsinoids on energy metabolism in human subjects.  

PubMed

Capsinoids are non-pungent compounds with molecular structures similar to capsaicin, which has accepted thermogenic properties. To assess the acute effect of a plant-derived preparation of capsinoids on energy metabolism, we determined RMR and non-protein respiratory quotient (NPRQ) after ingestion of different doses of the capsinoids. Thirteen healthy subjects received four doses of the capsinoids (1, 3, 6 and 12 mg) and placebo using a crossover, randomised, double-blind trial. After a 10 h overnight fast as inpatients, RMR was measured by indirect calorimetry for 45 min before and 120 min after ingesting capsinoids or placebo. Blood pressure and axillary temperature were measured before ( - 55 and - 5 min) and after (60 and 120 min) dosing. Before dosing, mean RMR was 6247 (se 92) kJ/d and NPRQ was 0.86 (se 0.01). At 120 min after dosing, metabolic rate and NPRQ remained similar across the four capsinoids and placebo doses. Capsinoids also had no influence on blood pressure or axillary temperature. Capsinoids provided in four doses did not affect metabolic rate and fuel partitioning in human subjects when measured 2 h after exposure. Longer exposure and higher capsinoids doses may be required to cause meaningful acute effects on energy metabolism. PMID:19671203

Galgani, Jose E; Ryan, Donna H; Ravussin, Eric

2009-08-12

285

Metabolic control analysis of integrated energy metabolism in permeabilized cardiomyocytes - experimental study.  

PubMed

The main focus of this research was to apply Metabolic Control Analysis to quantitative investigation of the regulation of respiration by components of the Mitochondrial Interactosome (MI, a supercomplex consisting of ATP Synthasome, mitochondrial creatine kinase (MtCK), voltage dependent anion channel (VDAC), and tubulin) in permeabilized cardiomyocytes. Flux control coefficients (FCC) were measured using two protocols: 1) with direct ADP activation, and 2) with MtCK activation by creatine (Cr) in the presence of ATP and pyruvate kinase-phosphoenolpyruvate system. The results show that the metabolic control is much stronger in the latter case: the sum of the measured FCC is 2.7 versus 0.74 (ADP activation). This is consistent with previous data showing recycling of ADP and ATP inside the MI due to the functional coupling between MtCK and ANT and limited permeability of VDAC for these compounds, PCr being the major energy carrier between the mitochondria and ATPases. In physiological conditions, when the MI is activated, the key sites of regulation of respiration in mitochondria are MtCK (FCC = 0.93), adenine nucleotide translocase ANT (FCC = 0.95) and CoQ cytochrome c oxidoreductase (FCC = 0.4). These results show clearly that under the physiological conditions the energy transfer from mitochondria to the cytoplasm is regulated by the MI supercomplex and is very sensitive to metabolic signals. PMID:21170421

Tepp, Kersti; Timohhina, Natalja; Chekulayev, Vladimir; Shevchuk, Igor; Kaambre, Tuuli; Saks, Valdur

2010-12-18

286

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

NASA Astrophysics Data System (ADS)

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.

1983-03-01

287

The Effect of Higher Sludge Recycling Rate on Anaerobic Treatment of Palm Oil Mill Effluent in a Semi-Commercial Closed Digester for Renewable Energy  

Microsoft Academic Search

Problem statement: A 500 m 3 semi-commercial closed anaerobic digester was constructed for Palm Oil Mill Effluent (POME) treatment and methane gas capture for renewable energy. During the start-up operation period, the Volatile Fatty A cids (VFA) accumulation could not be controlled and caused instability on the system. Approach: A settling tank was installed and sludge was recycl ed as

Alawi Sulaiman; Zainuri Busu; Meisam Tabatabaei; Shahrakbah Yacob; Suraini Abd-Aziz; Mohd Ali Hassan; Yoshihito Shirai

2009-01-01

288

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...

289

Energy metabolism of cancer: Glycolysis versus oxidative phosphorylation (Review).  

PubMed

Metabolic activities in normal cells rely primarily on mitochondrial oxidative phosphorylation (OXPHOS) to generate ATP for energy. Unlike in normal cells, glycolysis is enhanced and OXPHOS capacity is reduced in various cancer cells. It has long been believed that the glycolytic phenotype in cancer is due to a permanent impairment of mitochondrial OXPHOS, as proposed by Otto Warburg. This view is challenged by recent investigations which find that the function of mitochondrial OXPHOS in most cancers is intact. Aerobic glycolysis in many cancers is the combined result of various factors such as oncogenes, tumor suppressors, a hypoxic microenvironment, mtDNA mutations, genetic background and others. Understanding the features and complexity of the cancer energy metabolism will help to develop new approaches in early diagnosis and effectively target therapy of cancer. PMID:23226794

Zheng, Jie

2012-09-20

290

Energy metabolism of cancer: Glycolysis versus oxidative phosphorylation (Review)  

PubMed Central

Metabolic activities in normal cells rely primarily on mitochondrial oxidative phosphorylation (OXPHOS) to generate ATP for energy. Unlike in normal cells, glycolysis is enhanced and OXPHOS capacity is reduced in various cancer cells. It has long been believed that the glycolytic phenotype in cancer is due to a permanent impairment of mitochondrial OXPHOS, as proposed by Otto Warburg. This view is challenged by recent investigations which find that the function of mitochondrial OXPHOS in most cancers is intact. Aerobic glycolysis in many cancers is the combined result of various factors such as oncogenes, tumor suppressors, a hypoxic microenvironment, mtDNA mutations, genetic background and others. Understanding the features and complexity of the cancer energy metabolism will help to develop new approaches in early diagnosis and effectively target therapy of cancer.

ZHENG, JIE

2012-01-01

291

Medium chain fatty acid metabolism and energy expenditure: Obesity treatment implications  

Microsoft Academic Search

Fatty acids undergo different metabolic fates depending on their chain length and degree of saturation. The purpose of this review is to examine the metabolic handling of medium chain fatty acids (MCFA) with specific reference to intermediary metabolism and postprandial and total energy expenditure. The metabolic discrimination between varying fatty acids begins in the GI tract, with MCFA being absorbed

Andrea A. Papamandjaris; Diane E. Macdougall; Peter J. H. Jones

1998-01-01

292

Deranged energy substrate metabolism in the failing heart  

Microsoft Academic Search

Control of energy metabolism in the heart is closely linked to cardiac performance. Dysregulation of energygenerating pathways\\u000a occurs in many forms of heart disease, including heart failure. Uncertainty exists as to whether these alterations in the\\u000a way adenosine triphosphate (ATP) is produced serve to protect the heart from excessive oxygen demands or have untoward long-term\\u000a consequences. Regulation of fatty acid

Qi Tian; Philip M. Barger

2006-01-01

293

Metabolic Status Regulates Ghrelin Function on Energy Homeostasis  

Microsoft Academic Search

Ghrelin plays an important role in energy metabolism by regulating food intake, body weight and glucose homeostasis. In this review, we highlight recent developments describing how ghrelin stimulates neuropeptide Y (NPY) neurons, but not pro-opiomelanocortin neurons, to regulate food intake. We describe a novel signaling modality, in which ghrelin activates NPY\\/agouti-related protein (AgRP) neurons through fatty acid oxidation, reactive oxygen

Dana I. Briggs; Zane B. Andrews

2011-01-01

294

Proline impairs energy metabolism in cerebral cortex of young rats  

Microsoft Academic Search

In the present study we investigated the effect of acute hyperprolinemia on some parameters of energy metabolism, including\\u000a the activities of succinate dehydrogenase and cytocrome c oxidase and 14CO2 production from glucose and acetate in cerebral cortex of young rats. Lipid peroxidation determined by the levels of thiobarbituric\\u000a acid-reactive substances, as well as the influence of the antioxidants ?-tocopherol plus

Andréa G. K. Ferreira; Daniela D. Lima; Débora Delwing; Vanize Mackedanz; Bárbara Tagliari; Janaína Kolling; Patrícia F. Schuck; Moacir Wajner; Angela T. S. Wyse

2010-01-01

295

Energy metabolism in Desulfovibrio vulgaris Hildenborough: insights from transcriptome analysis  

SciTech Connect

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.

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

2007-11-01

296

[Dynamics of parameters of energy metabolism at adaptation to diving in human].  

PubMed

Studies of the diving reaction in the comparative-evolutionary aspect have shown that a complex of reactions providing the oxygen-saving effect during diving is inherent in human like in the secondary-aquatic mammals. This is confirmed by results of study of peculiarities of energy metabolism during imitation of diving (hold-up of respiration with immersion of face into the cold water--the cold-hypoxic-hypercapnic action) (CHHA). Data of gas analysis have shown that during the diving imitation the oxygen consumption rate is statistically significantly lower than during the usual hold-up of respiration (Genche's test). As shown by the study, this is due to the greater degree to vasoconstriction of peripheral vessels and selective redistribution of blood flow than to slowing down of the blood flow caused by reflex bradycardia during diving. It has been revealed that under effect of adaptation to CHHA, on the background of a decrease of the total energy consumption by the organism there occurs some increase of contribution of aerobic processes to its energy provision. Adaptation to CHHA has been shown to be accompanied by a decrease of reactivity of the parasympathetic chain of regulation of the heart chronotropic function and by an increase of duration of apnea. The duration of apnea is directly correlated with level of insulin--the hormone stimulating the anaerobic pathway of energy provision. Under effect of adaptation to CHHA there has been established an increase of the organism resistance to stress actions, which is confirmed by the lower levels of cortisol and thyroid hormones in representatives of the experimental group as compared with the control one. PMID:21061652

Baranova, T I; Kovalenko, R I; Mitrofanova, A V; Ianvareva, I N

297

Energy metabolism of intervertebral disc under mechanical loading.  

PubMed

Intervertebral disc (IVD) degeneration is closely associated with low back pain (LBP), which is a major health concern in the U.S. Cellular biosynthesis of extracellular matrix (ECM), which is important for maintaining tissue integrity and preventing tissue degeneration, is an energy demanding process. Due to impaired nutrient support in avascular IVD, adenosine triphosphate (ATP) supply could be a limiting factor for maintaining normal ECM synthesis. Therefore, the objective of this study was to investigate the energy metabolism in the annulus fibrosus (AF) and nucleus pulposus (NP) of porcine IVD under static and dynamic compressions. Under compression, pH decreased and the contents of lactate and ATP increased significantly in both AF and NP regions, suggesting that compression can promote ATP production via glycolysis and reduce pH by increasing lactate accumulation. A high level of extracellular ATP content was detected in the NP region and regulated by compressive loading. Since ATP can serve not only as an intra-cellular energy currency, but also as a regulator of a variety of cellular activities extracellularly through the purinergic signaling pathway, our findings suggest that compression-mediated ATP metabolism could be a novel mechanobiological pathway for regulating IVD metabolism. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1733-1738, 2013. PMID:23843186

Wang, Chong; Gonzales, Silvia; Levene, Howard; Gu, Weiyong; Huang, Chun-Yuh Charles

2013-07-10

298

Methods of assessing microbial activity and inhibition under anaerobic conditions: a literature review  

Microsoft Academic Search

This work reviews the existing methodologies for assessing microbial activity and inhibition under anaerobic conditions. The anaerobic digestion process consists of several metabolic steps–the Anaerobic Digestion Model No. 1 (ADM1) has attempted to describe these steps in the form of a mathematical model with the intention of providing a reference base for all further efforts in the modelling of anaerobic

Alberto Rozzi; Enrico Remigi

2004-01-01

299

Energy metabolism in human melanoma cells under hypoxic and acidic conditions in vitro.  

PubMed Central

The response to treatment and the malignant progression of tumours are influenced by the ability of the tumour cells to withstand severe energy deprivation during prolonged exposure to hypoxia at normal or low extracellular pH (pHe). The objective of the present work was to demonstrate intertumour heterogeneity under conditions of microenvironment-induced energy deprivation and to investigate whether the heterogeneity can be attributed to differences in the capacity of the tumour cells to generate energy in an oxygen-deficient microenvironment. Cultures of four human melanoma cell lines (BEX-c, COX-c, SAX-c, WIX-c) were exposed to hypoxia in vitro at pHe 7.4, 7.0 or 6.6 for times up to 31 h by using the steel-chamber method. High-performance liquid chromatography was used to assess adenylate energy charge as a function of exposure time. Cellular rates of glucose uptake and lactate release were determined by using standard enzymatic test kits. The adenylate energy charge decreased with time under hypoxia in all cell lines. The decrease was most pronounced shortly after the treatment had been initiated and then tapered off. BEX-c and SAX-c showed a significantly higher adenylate energy charge under hypoxic conditions than did COX-c and WIX-c whether the pHe was 7.4, 7.0 or 6.6, showing that tumours can differ in the ability to avoid energy deprivation during microenvironmental stress. There was no correlation between the adenylate energy charge and the rates of glucose uptake and lactate release. Intertumour heterogeneity in the ability to withstand energy deprivation in an oxygen-deficient microenvironment cannot therefore be attributed mainly to differences in the capacity of the tumour cells to generate energy by anaerobic metabolism. The data presented here suggest that the heterogeneity is rather caused by differences in the capacity of the tumour cells to reduce the rate of energy consumption when exposed to hypoxia.

SkA,yum, R.; Eide, K.; Berg, K.; Rofstad, E. K.

1997-01-01

300

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

Microsoft Academic Search

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

Teresa Shiflett

301

Anaerobic dormancy quantified in artemia embryos: a calorimetric test of the control mechanism.  

PubMed

Continuous measurement of heat dissipation from brine shrimp embryos during reversible transitions from aerobic development to anaerobic dormancy demonstrates a primary role for intracellular pH(pH(i))in this metabolic switching. Artificially elevating the depressed pH(i) during anoxia by adding ammonia markedly reactivates metabolism, as judged by increases in heat dissipation, trehalose catabolism, and the ratio of adenosine triphosphate to adenosine diphosphate. Energy flow during anaerobic dormancy is suppressed to 2.4 percent of aerobic values, which is the lowest percentage thus far reported for euryoxic animals. Use of diguanosine tetraphosphate stores cannot account for this observed heat dissipation. Thus, mobilizing trace amounts of trehalose may explain the energy metabolism during quiescence. PMID:17769739

Hand, S C; Gnaiger, E

1988-03-18

302

Anaerobic respiration in the polychaete Euzonus (Thoracophelia) mucronata  

Microsoft Academic Search

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

E. G. Ruby; D. L. Fox

1976-01-01

303

Involvement of pyruvate dehydrogenase in product formation in pyruvate-limited anaerobic chemostat cultures of Enterococcus faecalis NCTC 775  

Microsoft Academic Search

Enterococcus faecalis NCTC 775 was grown anaerobically in chemostat culture with pyruvate as the energy source. At low culture pH values, high in vivo and in vitro activities were found for both pyruvate dehydrogenase and lactate dehydrogenase. At high culture pH values the carbon flux was shifted towards pyruvate formate lyase. Some mechanisms possibly involved in this metabolic switch are

Jacky L. Snoep; M. Joost Teixeira de Mattos; Pieter W. Postma; Oense M. Neijssel

1990-01-01

304

Identification of distributed metabolic objectives in the hypermetabolic liver by flux and energy balance analysis  

Microsoft Academic Search

A methodology for inferring distributed metabolic objectives from time series flux data is developed by combining metabolic flux analysis, pathway identification, free energy balances, and nested optimization. This methodology is used to investigate the metabolic response of the rat liver to burn injury-induced whole body inflammation. Gibbs free energy changes were computed for stoichiometrically balanced sequences of reactions, or pathways,

Ryan P. Nolan; Andrew P. Fenley; Kyongbum Lee

2006-01-01

305

[Test for bioenergetic progress and specific energy metabolism in isopod crustaceans (Isopoda) of various ecology].  

PubMed

We studied energy metabolism of terrestrial and cavernicolous isopods and demonstrated much lower standard metabolism in the troglobionts as compared to other Isopoda representatives. The test for bioenergetic progress proved to be applicable for both aromorphosis and katamorphosis. Different patterns of the relationship between energy metabolism and temperature in stenothermal and eurythermal species have been proposed. PMID:12400381

Kle?menov, S Iu; Alekseeva, T A

306

Pioglitazone acutely reduces energy metabolism and insulin secretion in rats.  

PubMed

Our objective was to determine if the insulin-sensitizing drug pioglitazone acutely reduces insulin secretion and causes metabolic deceleration in vivo independently of change in insulin sensitivity. We assessed glucose homeostasis by hyperinsulinemic-euglycemic and hyperglycemic clamp studies and energy expenditure by indirect calorimetry and biotelemetry in male Wistar and obese hyperinsulinemic Zucker diabetic fatty (ZDF) rats 45 min after a single oral dose of pioglitazone (30 mg/kg). In vivo insulin secretion during clamped hyperglycemia was reduced in both Wistar and ZDF rats after pioglitazone administration. Insulin clearance was slightly increased in Wistar but not in ZDF rats. Insulin sensitivity in Wistar rats assessed by the hyperinsulinemic-euglycemic clamp was minimally affected by pioglitazone at this early time point. Pioglitazone also reduced energy expenditure in Wistar rats without altering respiratory exchange ratio or core body temperature. Glucose-induced insulin secretion (GIIS) and oxygen consumption were reduced by pioglitazone in isolated islets and INS832/13 cells. In conclusion, pioglitazone acutely induces whole-body metabolic slowing down and reduces GIIS, the latter being largely independent of the insulin-sensitizing action of the drug. The results suggest that pioglitazone has direct metabolic deceleration effects on the ?-cell that may contribute to its capacity to lower insulinemia and antidiabetic action. PMID:23378607

Lamontagne, Julien; Jalbert-Arsenault, Elise; Pepin, Emilie; Peyot, Marie-Line; Ruderman, Neil B; Nolan, Christopher J; Joly, Erik; Madiraju, S R Murthy; Poitout, Vincent; Prentki, Marc

2013-02-01

307

Anaerobic degradation of 4-hydroxybenzoate: Reductive dehydroxylation of 4-hydroxybenzoyl-CoA and ATP formation during 4-hydroxybenzoate decarboxylation by the phenol-metabolizing bacteria of a stable, strictly anaerobic consortium  

Microsoft Academic Search

4-Hydroxybenzoate was activated with coenzyme A by cells of a strictly anaerobic, phenol-degrading mixed culture to 4-hydroxybenzoyl-CoA, which was reductively dehydroxylated to benzoyl-CoA with reduced benzylviologen as an electron donor. The specific activity of the 4-hydroxybenzoyl-CoA ligase in cell-free extracts of the culture was 100–200 nmol min-1 mg-1, that of 4-hydroxybenzoyl-CoA reductase 14.5 nmol min-1 mg-1. An increased growth yield

C. Gallert; J. Winter

1994-01-01

308

[Seasonal changes in the energy metabolism of subarctic rodents].  

PubMed

In widespread species, northern taiga voles, most significant differences in the intensity of energy metabolism (M), maximum (Mmax) and reserve (Mres) metabolism were observed at winter temperatures (-5-20 degrees C): Clethrionomys rutilus greater than C. rufocanus greater than Microtus oeconomus; differences in seasonal increase of Mmax and Mres exhibit an inverse proportion. Seasonal changes in M and Mmax in autochthonous tundra rodents indicate that Lemmus sibiricus belongs to a more eurybiont species as compared to Dicrostonyx torquatus. The main characteristic feature of seasonal adaptation of M in lemmings, as compared to voles, is the evident decrease of M value in winter which is accompanied by a more significant increase of Mmax and Mres. Operative pattern and high seasonal mobility of chemical thermoregulation in lemmings are suggested which account for adaptation of these animals mainly to short-term extreme effects of low temperatures. PMID:2596207

Pastukhov, Iu F; Belogubova, E G

309

Effects of ingesting JavaFit Energy Extreme functional coffee on aerobic and anaerobic fitness markers in recreationally-active coffee consumers.  

PubMed

The purpose of this study was to examine the effects of ingesting JavaFittrade mark Energy Extreme (JEE) on aerobic and anaerobic performance measures in recreationally-active male and female coffee drinkers. Five male (27.6 +/- 4.2 yrs, 93.2 +/- 11.7 kg, 181.6 +/- 6.9 cm) and five female (29 +/- 4.6 yrs, 61.5 +/- 9.2 kg, 167.6 +/- 6.9 cm) regular coffee drinkers (i.e., 223.9 +/- 62.7 mg.d-1 of caffeine) participated in this study. In a cross-over, randomized design, participants performed a baseline (BASELINE) graded treadmill test (GXT) for peak VO2 assessment and a Wingate test for peak power. Approximately 3-4 d following BASELINE testing, participants returned to the lab for the first trial and ingested 354 ml of either JEE or decaffeinated coffee (DECAF), after which they performed a GXT and Wingate test. Criterion measures during the GXT included an assessment of peakVO2 at maximal exercise, as well as VO2 at 3 minutes and 10 minutes post-exercise. Additionally, time-to-exhaustion (TTE), maximal RPE, mean heart rate (HR), mean systolic pressure (SBP), and mean diastolic blood pressure (DBP) were measured during each condition. Criterion measures for the Wingate included mean HR, SBP, DBP, peak power, and time to peak power (TTP). Participants then returned to the lab approximately one week later to perform the second trial under the same conditions as the first, except consuming the remaining coffee. Data were analyzed using a one way ANOVA (p < 0.05). Our results indicate that JEE significantly increased VO2 at 3 minutes post-exercise when compared to BASELINE (p = 0.04) and DECAF (p = 0.02) values, which may be beneficial in enhancing post-exercise fat metabolism. PMID:18067677

Roberts, Michael D; Taylor, Lemuel W; Wismann, Jennifer A; Wilborn, Colin D; Kreider, Richard B; Willoughby, Darryn S

2007-12-08

310

Gene regulatory mechanisms governing energy metabolism during cardiac hypertrophic growth.  

PubMed

Studies in a variety of mammalian species, including humans, have demonstrated a reduction in fatty acid oxidation (FAO) and increased glucose utilization in pathologic cardiac hypertrophy, consistent with reinduction of the fetal energy metabolic program. This review describes results of recent molecular studies aimed at delineating the gene regulatory events which facilitate myocardial energy substrate switches during hypertrophic growth of the heart. Studies aimed at the characterization of transcriptional control mechanisms governing FAO enzyme gene expression in the cardiac myocyte have defined a central role for the fatty acid-activated nuclear receptor peroxisome proliferator-activated receptor alpha (PPAR(alpha)). Cardiac FAO enzyme gene expression was shown to be coordinately downregulated in murine models of ventricular pressure overload, consistent with the energy substrate switch away from fatty acid utilization in the hypertrophied heart. Nuclear protein levels of PPAR(alpha) decline in the ventricle in response to pressure overload, while several Sp and nuclear receptor transcription factors are induced to fetal levels, consistent with their binding to DNA as transcriptional repressors of rate-limiting FAO enzyme genes with hypertrophy. Knowledge of key components of this transcriptional regulatory pathway will allow for the development of genetic engineering strategies in mice that will modulate fatty acid oxidative flux and assist in defining whether energy metabolic derangements play a primary role in the development of pathologic cardiac hypertrophy and eventual progression to heart failure. PMID:11988641

Lehman, John J; Kelly, Daniel P

2002-04-01

311

Activin Signaling: Effects on Body Composition and Mitochondrial Energy Metabolism  

PubMed Central

Activin-?A and activin-?B (encoded by Inhba and Inhbb genes, respectively) are closely related TGF-? superfamily members that participate in a variety of biological processes. We previously generated mice with an insertion allele at the Inhba locus, InhbaBK. In this allele, the sequence encoding the Inhba mature domain is replaced with that of Inhbb, rendering the gene product functionally hypomorphic. Homozygous (InhbaBK/BK) and hemizygous (InhbaBK/?) mice are smaller and leaner than their wild-type littermates, and many tissues are disproportionately small relative to total body weight. To determine the mechanisms that contribute to these phenomena, we investigated the metabolic consequences of the mutation. Although the growth of InhbaBK mice is improved by providing a calorie-rich diet, diet-induced obesity, fatty liver, and insulin resistance (hallmarks of chronic caloric excess) do not develop, despite greater caloric intake than wild-type controls. Physiological, molecular, and biochemical analyses all revealed characteristics that are commonly associated with increased mitochondrial energy metabolism, with a corresponding up-regulation of several genes that reflect enhanced mitochondrial biogenesis and function. Oxygen consumption, an indirect measure of the metabolic rate, was markedly increased in InhbaBK/BK mice, and polarographic analysis of liver mitochondria revealed an increase in ADP-independent oxygen consumption, consistent with constitutive uncoupling of the inner mitochondrial membrane. These findings establish a functional relationship between activin signaling and mitochondrial energy metabolism and further support the rationale to target this signaling pathway for the medical treatment of cachexia, obesity, and diabetes.

Li, Liunan; Shen, Joseph J.; Bournat, Juan C.; Huang, Lihua; Chattopadhyay, Abanti; Li, Zhihong; Shaw, Chad; Graham, Brett H.; Brown, Chester W.

2009-01-01

312

Cytosolic Calcium Coordinates Mitochondrial Energy Metabolism with Presynaptic Activity  

PubMed Central

Most neurons fire in bursts, imposing episodic energy demands, but how these demands are coordinated with oxidative phosphorylation is still unknown. Here, using fluorescence imaging techniques on presynaptic termini of Drosophila motor neurons (MNs), we show that mitochondrial matrix pH (pHm), inner membrane potential (??m), and NAD(P)H levels ([NAD(P)H]m) increase within seconds of nerve stimulation. The elevations of pHm, ??m, and [NAD(P)H]m indicate an increased capacity for ATP production. Elevations in pHm were blocked by manipulations which blocked mitochondrial Ca2+ uptake, including replacement of extracellular Ca2+ with Sr2+, and application of either tetraphenylphosphonium chloride or KB-R7943, indicating that it is Ca2+ that stimulates presynaptic mitochondrial energy metabolism. To place this phenomenon within the context of endogenous neuronal activity, the firing rates of a number of individually identified MNs were determined during fictive locomotion. Surprisingly, although endogenous firing rates are significantly different, there was little difference in presynaptic cytosolic Ca2+ levels ([Ca2+]c) between MNs when each fires at its endogenous rate. The average [Ca2+]c level (329±11nM) was slightly above the average Ca2+ affinity of the mitochondria (281±13nM). In summary, we show that when MNs fire at endogenous rates [Ca2+]c is driven into a range where mitochondria rapidly acquire Ca2+. As we also show that Ca2+ stimulates presynaptic mitochondrial energy metabolism, we conclude that [Ca2+]c levels play an integral role in coordinating mitochondrial energy metabolism with presynaptic activity in Drosophila MNs.

Chouhan, Amit K.; Ivannikov, Maxim V.; Lu, Zhongmin; Sugimori, Mutsuyuki; Llinas, Rodolfo R.; Macleod, Gregory T.

2012-01-01

313

Legal pre-event nutritional supplements to assist energy metabolism.  

PubMed

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

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

2008-01-01

314

FY 1987 Anaerobic Digestion: Annual Report.  

National Technical Information Service (NTIS)

Anaerobic digestion research is being undertaken by the Department of Energy (DOE) under the field management of the Solar Energy Research Institute (SERI) and is sponsored as part of the Energy from Municipal Waste Research Program to produce methane fro...

1988-01-01

315

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

PubMed

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

Arakelova, E S

316

Effect of pipradrol on energy metabolism of the brain during prolonged muscular activity  

Microsoft Academic Search

Under the influence of prolonged muscular work (swimming for 5 h) the content of ATP, ADP, AMP, and creatine phosphate in the brain of albino rats was reduced, while anaerobic carbohydrate breakdown was intensified. The lowered concentration of high-energy phosphates was due to a deficiency of their resynthesis because of disturbance of the coupling of oxidative phosphorylation and of the

A. S. Saratikov; T. A. Revina; A. I. Ryzhov; B. Yu. Sal'nik

1971-01-01

317

Application of the Fuel-Linked Energy Resources and Tasks (FLERT) approach to rural household and community-scale anaerobic-digestion systems  

SciTech Connect

The introduction of anaerobic digesters into rural households and communities in Asia and the Pacific has often been unsuccessful due to the failure to assess not only local energy needs and resources, but also the social and environmental appropriateness of the new technology. The Fuel-Linked Energy Resources and Tasks (FLERT) approach presented here provides a well-defined and replicative framework for examining the physical, social, and environmental resources used and the products generated by anaerobic digesters and for predicting whether digesters will or will not be appropriate in specific situations. With limited data derived from literature review, the anaerobic digestion system is analyzed in terms of construction, operations and maintenance, management of feedstock raw materials and of residues, and energy distribution and use. Three types of digesters are included in the analysis - floating-dome, fixed-dome, and bag-type digesters. Tasks that might be promoted in rural areas by the energy and other products provided by digesters are appraised and some implications of using these products are discussed, based on actual experiences. A model for comparing condensed sets of data from alternative energy technologies is presented. A five-page bibliography (1956-80) is included.

Santerre, M.T.; Smith, K.R.

1980-09-01

318

Metabolic adaptation for low energy throughput in orangutans  

PubMed Central

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.

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

2010-01-01

319

Arsenic, Anaerobes, and Autotrophy  

Microsoft Academic Search

That microbes have resistance to the toxic arsenic oxyanions arsenite [As(III)] and arsenate [As(V)] has been recognized for some time. More recently it was shown that certain prokaryotes can demonstrate As- dependent growth by conserving the energy gained from the aerobic oxidation of As(III) to As(V), or from the reduction of As(V) to As(III) under anaerobic conditions. During the course

R. S. Oremland

2008-01-01

320

Investigation of Intermediary Metabolism and Energy Exchange Following Human Trauma.  

National Technical Information Service (NTIS)

Contents: Muscle Composition in Injury, Sepsis and Depletion; Glucose Metabolism in Human Injury, Sepsis and Depletion; Regional Metabolism in Injury, Sepsis and Depletion Nutritional Characterization of Patients for Study; and Studies of Lipid Metabolism...

J. M. Kinney

1979-01-01

321

The genome sequence of Desulfatibacillum alkenivorans AK-01: a blueprint for anaerobic alkane oxidation.  

PubMed

Desulfatibacillum alkenivorans AK-01 serves as a model organism for anaerobic alkane biodegradation because of its distinctive biochemistry and metabolic versatility. The D. alkenivorans genome provides a blueprint for understanding the genetic systems involved in alkane metabolism including substrate activation, CoA ligation, carbon-skeleton rearrangement and decarboxylation. Genomic analysis suggested a route to regenerate the fumarate needed for alkane activation via methylmalonyl-CoA and predicted the capability for syntrophic alkane metabolism, which was experimentally verified. Pathways involved in the oxidation of alkanes, alcohols, organic acids and n-saturated fatty acids coupled to sulfate reduction and the ability to grow chemolithoautotrophically were predicted. A complement of genes for motility and oxygen detoxification suggests that D. alkenivorans may be physiologically adapted to a wide range of environmental conditions. The D. alkenivorans genome serves as a platform for further study of anaerobic, hydrocarbon-oxidizing microorganisms and their roles in bioremediation, energy recovery and global carbon cycling. PMID:21651686

Callaghan, A V; Morris, B E L; Pereira, I A C; McInerney, M J; Austin, R N; Groves, J T; Kukor, J J; Suflita, J M; Young, L Y; Zylstra, G J; Wawrik, B

2011-06-08

322

[Energy metabolism in laying hens of different body weight genotypes].  

PubMed

Energy metabolism and some performance parameters were investigated in laying hens of 3 different body weight-genotypes: 6 x 7 (normal-sized, crossbred from normal-sized male and female lines, group 1), 47 x 38 (dwarf-sized, breeding from a dwarf-sized male line and a normal-sized female line, group 2) and 44 x 47 (dwarf-sized, breeding from dwarf-sized male and female lines, group 3). Energy balance was measured by indirect calorimetry through C- and N-balances in 12 animals of each group during 10 consecutive days at production peak, within the period between the 27th and the 37th week of age. Hens were caged individually at 23 degrees C environmental temperature and fed ad libitum on a laying mash. The mean body weight in the dwarf-sized groups 2 and 3 was 32% lower than in the normal-sized group 1 during the energy balance period. The daily gross energy intake in group 2 and 3 was decreased by 33 and 34%, respectively. There were no significant differences in digestibility and metabolizability of gross energy between the groups. The energy requirements for maintenance [kJ ME/kg0.75.d] derived from the energy balances were lower by 4% (P > 0.05) and 14% (P < 0.05) in the dwarf-sized groups 2 and 3 as compared with the normal-sized group 1, when equal coefficients of partial efficiency of metabolizable energy utilization for energy retention in body and eggs are assumed for the 3 body-mass genotypes. There were no relevant differences in body composition at the end of the energy balance periods as well as in egg composition between the 3 experimental groups. PMID:9850795

Klein, M; Neubert, M; Strobel, E; Hoffmann, L

1998-01-01

323

High density lipoprotein cholesterol following anaerobic swimming in trained swimmers.  

PubMed

HDL-C, LDL-C, total cholesterol and glycerol were determined in venous blood of 10 male trained swimmers at rest and following 100-m anaerobic swimming. When compared to rest levels, the peak HDL-C and glycerol concentrations were significantly enhanced following anaerobic swim test (p < 0.01). However, peak LDL-C and total cholesterol after anaerobic swim were not significantly increased compared with the rest level. The present data demonstrated that the anaerobic swimming induces an increase in HDL-C metabolism, suggesting that the anaerobic exercise per se was one reason for the elevated HDL-C levels. PMID:8412058

Ohkuwa, T; Itoh, H

1993-06-01

324

Islet transplantation in diabetic rats normalizes basal and exercise-induced energy metabolism  

Microsoft Academic Search

Summary  Transplantation of islets of Langerhans in diabetic rats normalizes resting glucose and insulin levels, but it remains unclear whether islet transplantation restores resting and exercise-induced energy metabolism. Therefore, we compared energy metabolism in islet transplanted rats with energy metabolism in normal controls and in streptozotocin-induced diabetic rats. Indirect calorimetry was applied before, during, and after moderate swimming exercise. Blood was

H. Houwing; L. Benthem; P. T. R. Van Suylichem; J. Van der Leest; J. H. Strubbe; A. B. Steffens

1995-01-01

325

Optimizing cardiac energy substrate metabolism: a novel therapeutic intervention for ischemic heart disease  

Microsoft Academic Search

Ischemic heart diseases, encompassing and ranging from angina pectoris to acute myocardial infarction, have a major impact on both cardiac energy metabolism and cardiac function. In the normal heart, energy metabolism and function are exquisitely matched. However, during and after ischemia there are both a decrease in energy production and disturbances in the balance between use of fatty acid and

Jagdip S. Jaswal; Virgilio J. J. Cadete; Gary D. Lopaschuk

326

Microbial population dynamics during startup of a full-scale anaerobic digester treating industrial food waste in Kyoto eco-energy project  

Microsoft Academic Search

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,

Michihiko Ike; Daisuke Inoue; Tomoki Miyano; Tong Tong Liu; Kazunari Sei; Satoshi Soda; Shiro Kadoshin

2010-01-01

327

Anaerobic Nitrate-Dependent Metal Bio-Oxidation  

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

328

Operating aerobic wastewater treatment at very short sludge ages enables treatment and energy recovery through anaerobic sludge digestion.  

PubMed

Conventional abattoir wastewater treatment processes for carbon and nutrient removal are typically designed and operated with a long sludge retention time (SRT) of 10-20 days, with a relatively high energy demand and physical footprint. The process also generates a considerable amount of waste activated sludge that is not easily degradable due to the long SRT. In this study, an innovative high-rate sequencing batch reactor (SBR) based wastewater treatment process with short SRT and hydraulic retention time (HRT) is developed and characterised. The high-rate SBR process was shown to be most effective with SRT of 2-3 days and HRT of 0.5-1 day, achieving >80% reduction in chemical oxygen demand (COD) and phosphorus and approximately 55% nitrogen removal. A majority of carbon removal (70-80%) was achieved by biomass assimilation and/or accumulation, rather than oxidation. Anaerobic degradability of the sludge generated in the high-rate SBR process was strongly linked to SRT, with measured degradability extent being 85% (2 days SRT), 73% (3 days), and 63% (4 days), but it was not influenced by digestion temperature. However, the rate of degradation for 3 and 4 days SRT sludge was increased by 45% at thermophilic conditions compared to mesophilic conditions. Overall, the treatment process provides a very compact and energy efficient treatment option for highly degradable wastewaters such as meat and food processing, with a substantial space reduction by using smaller reactors and a considerable net energy output through the reduced aerobic oxidation and concurrent increased methane production potential through the efficient sludge digestion. PMID:24045213

Ge, Huoqing; Batstone, Damien J; Keller, Jurg

2013-08-28

329

Anaerobic pre-treatment of herbal-based pharmaceutical wastewater using fixed-film reactor with recourse to energy recovery.  

PubMed

The concept of immobilization technology has been incorporated in this research study for biomethanation of high strength herbal based pharmaceutical wastewater. Accordingly, an investigation has been made on laboratory scale to assess the feasibility of an anaerobic fixed film fixed bed reactor system to pre-treat herbal-based pharmaceutical wastewater with recourse to energy recovery, including influence of operating conditions. The work was carried out with laboratory-scale upflow reactor, equipped with nylon scrubber as random support. The reactor was operated at 35 degrees C. COD removal efficiencies ranging from 76 to 98% were achieved for organic loading rates upto 10 kgCOD/m3 d, while the highest organic loading rate (around 48 kg COD/m3 d) led to efficiencies of 46-50%. The influences of hydraulic retention time and substrate concentration were also studied. The reactors did now show destabilization under impulse hydraulic and organic overloadings. Reactor stability was easily achieved under intermittent operation, with breaks, after which the reactors rapidly returned to their optimal performance. PMID:11228986

Nandy, T; Kaul, S N

2001-02-01

330

BIOLEACHING OF METALS FROM ANAEROBIC SEWAGE SLUDGE: EFFECTS OF TOTAL SOLIDS, LEACHING MICROORGANISMS, AND ENERGY SOURCE  

Microsoft Academic Search

The effects of municipal sewage sludge solids concentration, leaching microorganisms (Thiobacillus thiooxidans or Thiobacillus ferrooxidans) and the addition of energy source (S or Fe(II)) on the bioleaching of metals from sewage sludge has been investigated under laboratory conditions using shake flasks. The results show that metal solubilization was better accomplished if additional energy source is supplemented to the microorganisms and

Ana T. Lombardi; Oswaldo Garcia Jr; Antonio A. Mozeto

2001-01-01

331

Lactate Dehydrogenase C and Energy Metabolism in Mouse Sperm1  

PubMed Central

We demonstrated previously that disruption of the germ cell-specific lactate dehydrogenase C gene (Ldhc) led to male infertility due to defects in sperm function, including a rapid decline in sperm ATP levels, a decrease in progressive motility, and a failure to develop hyperactivated motility. We hypothesized that lack of LDHC disrupts glycolysis by feedback inhibition, either by causing a defect in renewal of the NAD+ cofactor essential for activity of glyceraldehyde 3-phosphate dehydrogenase, sperm (GAPDHS), or an accumulation of pyruvate. To test these hypotheses, nuclear magnetic resonance analysis was used to follow the utilization of labeled substrates in real time. We found that in sperm lacking LDHC, glucose consumption was disrupted, but the NAD:NADH ratio and pyruvate levels were unchanged, and pyruvate was rapidly metabolized to lactate. Moreover, the metabolic disorder induced by treatment with the lactate dehydrogenase (LDH) inhibitor sodium oxamate was different from that caused by lack of LDHC. This supported our earlier conclusion that LDHA, an LDH isozyme present in the principal piece of the flagellum, is responsible for the residual LDH activity in sperm lacking LDHC, but suggested that LDHC has an additional role in the maintenance of energy metabolism in sperm. By coimmunoprecipitation coupled with mass spectrometry, we identified 27 proteins associated with LDHC. A majority of these proteins are implicated in ATP synthesis, utilization, transport, and/or sequestration. This led us to hypothesize that in addition to its role in glycolysis, LDHC is part of a complex involved in ATP homeostasis that is disrupted in sperm lacking LDHC.

Odet, Fanny; Gabel, Scott A.; Williams, Jason; London, Robert E.; Goldberg, Erwin; Eddy, Edward M.

2011-01-01

332

Energetics of end product excretion in anaerobic bacteria and the metabolism of fatty acids by Syntrophomonas wolfei: Progress report, November 16, 1986-November 15, 1987  

SciTech Connect

We have studied the growth and metabolism of Syntrophomonas wolfei in pure culture with crotonate as the energy source. S. wolfei grows in crotonate mineral salts medium without rumen fluid with cobalamin, thymine, lipoic acid and biotin added. However, after four to six transfers in this medium, growth ceases, indicating that another vitamin is required. The chemically defined medium allows large batches of S. wolfei to be grown for enzyme purification. All the enzymes involved in the oxidation of crotonyl-CoA to acetate have been detected. The pure culture of S. wolfei or coculture of S. wolfei grown with crotonate contain high activities of a crotonate: acetyl-CoA CoA-transferase activity. This activity is not detected in cocultures grown with butyrate. Thus, we believe that the reason why S. wolfei can now grow with crotonate is that an alteration or mutation occurred which allows the organism to activate this crotonate. S. wolfei also makes small amounts of H/sub 2/ when grown in pure culture with crotonate. A methyl viologen-dependent hydrogenase activity was found. We have also demonstrated the production of H/sub 2/ from 3-hydroxybutyryl-CoA in cell-free extracts of S. wolfei by coupling H/sub 2/ production to CH/sub 4/ production with the addition of Methanobacterium bryantii and directly using a hydrogen electrode. These results clearly show that S. wolfei makes H/sub 2/. S. wolfei does not contain formate dehydrogenase or CO dehydrogenase activities.

McInerney, M.J.

1987-01-01

333

Viable energy production and waste recycling from anaerobic digestion of manure and other biomass materials  

Microsoft Academic Search

Energy prices and energy sales possibilities seem to be the most important preconditions for the viability of agricultural biogas plants. Some countries provide opportunities for electricity sale at prices of approximately US$ 0.10-0.15 per kWh. This price level provides sufficient incentive for farmers and other investors to become interested. In other countries, where much lower prices are offered, agricultural biogas

S Tafdrup

1995-01-01

334

Energy metabolism of experimental wounds at various oxygen environments.  

PubMed Central

Energy metabolism of healing tissue was studied in experimental wounds of rats chronically breathing 11% O2, air or 55% O2. Increasing oxygen supply elevated both PO2 and PCO2 in the wound tissue. At the early phases of healing hypoxic wounds contained less DNA than normoxic or hyperoxic tissues. In hypoxia the accumulation of wound collagen was clearly retarded. Furthermore, tissue taken from wounds healing in hypoxic environments and tested ex vivo in air showed decreased capacity for glucose utilization, lactate production and oxygen consumption. Concentrations of AMP, ADP and ATP in repair tissue increased as healing progressed. The more oxygen available the higher the amounts of ADP and ATP. The AMP content was not affected by changes in local oxygen tension. These results support the earlier concept that the supply of oxygen in healing tissue may be rate-limitimg. Reduction of available oxygen either by systemic hypoxia or by increased diffusion distance impedes healing.

Kivisaari, J; Vihersaari, T; Renvall, S; Niinikoski, J

1975-01-01

335

Proline impairs energy metabolism in cerebral cortex of young rats.  

PubMed

In the present study we investigated the effect of acute hyperprolinemia on some parameters of energy metabolism, including the activities of succinate dehydrogenase and cytocrome c oxidase and (14)CO(2) production from glucose and acetate in cerebral cortex of young rats. Lipid peroxidation determined by the levels of thiobarbituric acid-reactive substances, as well as the influence of the antioxidants alpha-tocopherol plus ascorbic acid on the effects elicited by Pro on enzyme activities and on the lipid peroxidation were also evaluated. Wistar rats of 12 and 29 days of life received one subcutaneous injection of saline or proline (12.8 or 18.2 micromol/g body weight, respectively) and were sacrificed 1 h later. In another set of experiments, 5- and 22-day-old rats were pretreated for a week with daily intraperitoneal administration of alpha-tocopherol (40 mg/kg) plus ascorbic acid (100 mg/kg) or saline. Twelve hours after the last injection, rats received one injection of proline or saline and were sacrificed 1 h later. Results showed that acute administration of proline significantly reduced cytochrome c oxidase activity and increased succinate dehydrogenase activity and (14)CO(2) production in cerebral cortex, suggesting that Pro might disrupt energy metabolism in brain of young rats. In addition, proline administration increased the thiobarbituric acid-reactive substances levels, which were prevented by antioxidants. These findings suggest that mitochondrial dysfunction and oxidative stress may be important contributors to the neurological dysfunction observed in some hyperprolinemic patients and that treatment with antioxidants may be beneficial in this pathology. PMID:20437088

Ferreira, Andréa G K; Lima, Daniela D; Delwing, Débora; Mackedanz, Vanize; Tagliari, Bárbara; Kolling, Janaína; Schuck, Patrícia F; Wajner, Moacir; Wyse, Angela T S

2010-05-01

336

Treponema succinifaciens sp. nov., an anaerobic spirochete from the swine intestine  

Microsoft Academic Search

The morphology, the general physiological characteristics, and the energy-yielding metabolism of an obligately anaerobic spirochete isolated from the colon of a swine were studied. Electron microscopy showed that the helical spirochetal cells possessed an outer sheath, a protoplasmic cylinder, and 4 periplasmic fibrils in a 2-4-2 arrangement. The spirochete grew in an atmosphere of N2 in prereduced media containing a

W. M. Cwyk; E. Canale-Parola

1979-01-01

337

2-arachidonoylglycerol signaling in forebrain regulates systemic energy metabolism.  

PubMed

The endocannabinoid system plays a critical role in the control of energy homeostasis, but the identity and localization of the endocannabinoid signal involved remain unknown. In the present study, we developed transgenic mice that overexpress in forebrain neurons the presynaptic hydrolase, monoacylglycerol lipase (MGL), which deactivates the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG). MGL-overexpressing mice show a 50% decrease in forebrain 2-AG levels but no overt compensation in other endocannabinoid components. This biochemical abnormality is accompanied by a series of metabolic changes that include leanness, elevated energy cost of activity, and hypersensitivity to ?(3)-adrenergic-stimulated thermogenesis, which is corrected by reinstating 2-AG activity at CB(1)-cannabinoid receptors. Additionally, the mutant mice are resistant to diet-induced obesity and express high levels of thermogenic proteins, such as uncoupling protein 1, in their brown adipose tissue. The results suggest that 2-AG signaling through CB(1) regulates the activity of forebrain neural circuits involved in the control of energy dissipation. PMID:22405068

Jung, Kwang-Mook; Clapper, Jason R; Fu, Jin; D'Agostino, Giuseppe; Guijarro, Ana; Thongkham, Dean; Avanesian, Agnesa; Astarita, Giuseppe; DiPatrizio, Nicholas V; Frontini, Andrea; Cinti, Saverio; Diano, Sabrina; Piomelli, Daniele

2012-03-01

338

Anaerobic Digestion of Agricultural Solid Residues  

Microsoft Academic Search

Agricultural residues can be converted to methane-rich gas mixture. Anaerobic biomethane production is an effective process for conversion of a broad variety of agricultural residues to methane to substitute natural gas and medium calorific value gases. Methane generating bacteria (methanogens) and other microbes that help digest dying plants in anaerobic conditions. Agricultural solid residues (ASR) represent a potential energy resource

Ayhan Demirbas; Temel Ozturk

2005-01-01

339

Energy Metabolism and Leptin: Effects on Neuroendocrine Regulation of Reproduction in the Gilt and Sow  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is well established that reproductive function is metabolically gated. However, the mechanisms whereby energy stores and metabolic cues influence appetite, energy homeostasis and fertility are yet to be completely understood. Adipose tissue is no longer considered as only a depot to store exces...

340

Glycerol: An unexpected major metabolite of energy metabolism by the human malaria parasite  

Microsoft Academic Search

BACKGROUND: Malaria is a global health emergency, and yet our understanding of the energy metabolism of the principle causative agent of this devastating disease, Plasmodium falciparum, remains rather basic. Glucose was shown to be an essential nutritional requirement nearly 100 years ago and since this original observation, much of the current knowledge of Plasmodium energy metabolism is based on early

Lu-Yun Lian; Mohammed Al-Helal; Abd Majid Roslaini; Nicholas Fisher; Patrick G Bray; Stephen A Ward; Giancarlo A Biagini

2009-01-01

341

Anaerobic biodegradation of aromatic compounds.  

PubMed

Many aromatic compounds and their monomers are existing in nature. Besides they are introduced into the environment by human activity. The conversion of these aromatic compounds is mainly an aerobic process because of the involvement of molecular oxygen in ring fission and as an electron acceptor. Recent literatures indicated that ring fission of monomers and obligomers mainly occurs in anaerobic environments through anaerobic respiration with nitrate, sulphate, carbon dioxide or carbonate as electron acceptors. These anaerobic processes will help to work out the better situation for bioremediation of contaminated environments. While there are plenty of efforts to reduce the release of these chemicals to the environment, already contaminated sites need to be remediated not only to restore the sites but to prevent the leachates spreading to nearby environment. Basically microorganisms are better candidates for breakdown of these compounds because of their wider catalytic mechanisms and the ability to act even in the absence of oxygen. These microbes can be grouped based on their energy mechanisms. Normally, the aerobic counterparts employ the enzymes like mono-and-dioxygenases. The end product is basically catechol, which further may be metabolised to CO2 by means of quinones reductases cycles. In the absense of reductases compounds, the reduced catechols tend to become oxidised to form many quinone compounds. The quinone products are more recalcitrant and lead to other aesthetic problems like colour in water, unpleasant odour, etc. On the contrary, in the reducing environment this process is prevented and in a cascade of pathways, the cleaved products are converted to acetyl co-A to be integrated into other central metabolite paths. The central metabolite of anaerobic degradation is invariably co-A thio-esters of benzoic acid or hydroxy benzoic acid. The benzene ring undergoes various substitution and addition reactions to form chloro-, nitro-, methyl- compounds. For complete degradation the side chains must be removed first and then the benzene ring is activated by carboxylation or hydroxylation or co-A thioester formation. In the next step the activated ring is converted to a form that can be collected in the central pool of metabolism. The third step is the channeling reaction in which the products of the catalysis are directed into central metabolite pool. The enzymes involved in these mechanisms are mostly benzyl co-A ligase, benzyl alcohol dehydrogenase. Other enzymes involved in this path are yet to be purified though many of the reactions products that have been theoretically postulated have been identified. This is mainly due to the instability of intermediate compounds as well as the association of the enzyme substrate is femoral and experimental conditions need to be sophisticated further for isolation of these enzymes. The first structural genes of benzoate and hydroxy benzoate ligases were isolated from Rhodopseudomonas palustris. This gene cluster of 30 kb size found in Rhodopseudomonas palustris coded for the Bad A protein. Similarly, some of the bph A,B,C and D cluster of genes coding for the degradation of pentachlorobenzenes were located in Pseudomonas pseudoalgaligenesKF 707. PMID:15242297

Jothimani, P; Kalaichelvan, G; Bhaskaran, A; Selvaseelan, D Augustine; Ramasamy, K

2003-09-01

342

Use of 31P Magnetic Resonance Spectroscopy to Study the Effect of Cortical Magnesium and Energy Metabolism after Subarachnoid Hemorrhage  

Microsoft Academic Search

Background: Flow metabolism coupling ensures adequate cerebral oxygenation. When subarachnoid hemorrhage (SAH) occurs, the flow metabolism coupling lost its balance and results in cerebral ischemia and infarction second to cortical magnesium and energy metabolism alternation. During chronic vasospasm, change in cortical energy metabolism is coupled with change in cerebral blood flow after SAH. Methods: What kind of noninvasive technique can

Heping Yang; Xiangqi Tang; Lihua Tan; Liuwang Zeng; Zhiping Hu

2008-01-01

343

Predicting Changes of Body Weight, Body Fat, Energy Expenditure and Metabolic Fuel Selection in C57BL\\/6 Mice  

Microsoft Academic Search

The mouse is an important model organism for investigating the molecular mechanisms of body weight regulation, but a quantitative understanding of mouse energy metabolism remains lacking. Therefore, we created a mathematical model of mouse energy metabolism to predict dynamic changes of body weight, body fat, energy expenditure, and metabolic fuel selection. Based on the principle of energy balance, we constructed

Juen Guo; Kevin D. Hall; Pere-Joan Cardona

2011-01-01

344

Potential application of anaerobic extremophiles for hydrogen production  

NASA Astrophysics Data System (ADS)

In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the 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 furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data with the rates of hydrogen productivity for S. americana ASpG1 isolated from soda Mono Lake in California.

Pikuta, Elena V.; Hoover, Richard B.

2004-11-01

345

One-Carbon Metabolism in Anaerobes: Organic Acid and Methane Production: Final Technical Report for Period June 1, 1985-May 31,1987.  

National Technical Information Service (NTIS)

Objectives of this project dealt with understanding one- and multicarbon metabolism in acetogenic and methanogenic bacteria. The biochemistry of acetate catabolism in Methanosarcina barkeri in relation to their major enzyme activities, co-factors and inte...

J. G. Zeikus

1987-01-01

346

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

Microsoft Academic Search

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 COâ incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas

D. J. Roberts; P. M. Fedorak; S. E. Hrudey

1990-01-01

347

Metabolomics analysis of Cistus monspeliensis leaf extract on energy metabolism activation in human intestinal cells.  

PubMed

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

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

2012-03-18

348

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

PubMed Central

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.

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

2012-01-01

349

The Influence of Hydration on Anaerobic Performance: A Review  

ERIC Educational Resources Information Center

|This review examines the influence of dehydration on muscular strength and endurance and on single and repeated anaerobic sprint bouts. Describing hydration effects on anaerobic performance is difficult because various exercise modes are dominated by anaerobic energy pathways, but still contain inherent physiological differences. The critical…

Kraft, Justin A.; Green, James M.; Bishop, Phillip A.; Richardson, Mark T.; Neggers, Yasmin H.; Leeper, James D.

2012-01-01

350

Microbial metabolism of tholin  

NASA Astrophysics Data System (ADS)

In this paper, we show that a wide variety of common soil bacteria are able to obtain their carbon and energy needs from tholin (a class of complex organic heteropolymers thought to be widely distributed through the solar system; in this case tholin was produced by passage of electrical discharge through a mixture of methane, ammonia, and water vapor). We have isolated aerobic, anaerobic, and facultatively anaerobic bacteria which are able to use tholin as a sole carbon source. Organisms which metabolize tholin represent a variety of bacterial genera including Clostridium, Pseudomonas, Bacillus, Acinetobacter, Paracoccus, Alcaligenes, Micrococcus, Cornebacterium, Aerobacter, Arthrobacter, Flavobacterium,and Actinomyces. Aerobic tholin-using bacteria were firrst isolated from soils containing unusual or sparse carbon sources. Some of these organisms were found to be facultatively anaerobic. Strictly anaerobic tholin-using bacteria were isolated from both carbon-rich and carbon-poor anaerobic lake muds. In addition, both aerobic and anaerobic tholin-using bacteria were isolated from common soil collected outside the laboratory building. Some, but not all, of the strains that were able to obtain carbon from tholin were also able to obtain their nitrogen requirements from tholin. Bacteria isolated from common soils were tested for their ability to obtain carbon from the water-soluble fraction, the ethanol-soluble fraction, and the water/ethanol-insoluble fraction of the tholin. Of the 3.5 × 10 7 bacteria isolated per gram of common soils, 1.7 0.5, and 0.2%, respectively, were able to obtaib their carbon requirements from the water-soluble fraction, the ethanol-soluble fraction and the water/ethanol-insoluble fraction of the tholin. The palatability of tholins to modern microbes may have implications for the early evolution of microbial life on Earth. Tholins may have formed the base of the food chain for an early heterotrophic biosphere before the evolution of autotrophy on the early Earth. Where tholins are present on other planets, they could possibly be metabolized by contaminant microorganisms transported to these bodies via spacecraft. Thus, the presence of tholins should be taken into account when evaluating the planetary quarantine requirements for probes to other planets.

Stoker, C. R.; Boston, P. J.; Mancinelli, R. L.; Segal, W.; Khare, B. N.; Sagan, C.

1990-05-01

351

Microbial metabolism of tholin.  

PubMed

In this paper, we show that a wide variety of common soil bacteria are able to obtain their carbon and energy needs from tholin (a class of complex organic heteropolymers thought to be widely distributed through the solar system; in this case tholin was produced by passage of electrical discharge through a mixture of methane, ammonia, and water vapor). We have isolated aerobic, anaerobic, and facultatively anaerobic bacteria which are able to use tholin as a sole carbon source. Organisms which metabolize tholin represent a variety of bacterial genera including Clostridium, Pseudomonas, Bacillus, Acinetobacter, Paracoccus, Alcaligenes, Micrococcus, Corynebacterium, Aerobacter, Arthrobacter, Flavobacterium, and Actinomyces. Aerobic tholin-using bacteria were first isolated from soils containing unusual or sparse carbon sources. Some of these organisms were found to be facultatively anaerobic. Strictly anaerobic tholin-using bacteria were isolated from both carbon-rich and carbon-poor anaerobic lake muds. In addition, both aerobic and anaerobic tholin-using bacteria were isolated from common soil collected outside the laboratory building. Some, but not all, of the strains that were able to obtain carbon from tholin were also able to obtain their nitrogen requirements from tholin. Bacteria isolated from common soils were tested for their ability to obtain carbon from the water-soluble fraction, the ethanol-soluble fraction, and the water/ethanol-insoluble fraction of the tholin. Of the 3.5 x 10(7) bacteria isolated per gram of common soils, 1.7, 0.5, and 0.2%, respectively, were able to obtain their carbon requirements from the water-soluble fraction, the ethanol-soluble fraction and the water/ethanol-insoluble fraction of the tholin. The palatability of tholins to modern microbes may have implications for the early evolution of microbial life on Earth. Tholins may have formed the base of the food chain for an early heterotrophic biosphere before the evolution of autotrophy on the early Earth. Where tholins are present on other planets, they could possibly be metabolized by contaminant microorganisms transported to these bodies via spacecraft. Thus, the presence of tholins should be taken into account when evaluating the planetary quarantine requirements for probes to other planets. PMID:11538367

Stoker, C R; Boston, P J; Mancinelli, R L; Segal, W; Khare, B N; Sagan, C

1990-01-01

352

Metabolic conditions in Porcine longissimus muscle immediately pre-slaughter and its influence on peri- and post mortem energy metabolism  

Microsoft Academic Search

To clarify the physiological prerequisites for the course of energy metabolism post mortem, 80 pigs consisting of four females from each of 20 litters of crossbreeds (Duroc as sireline and Danish Landrace×Danish Large White as dam line) were within litter allocated to four different treatments (A, B, C and D) to provide a large variation in the concentration of the

Poul Henckel; Anders Karlsson; Mogens T Jensen; Niels Oksbjerg; Jette Søholm Petersen

2002-01-01

353

Metabolic energy from arsenite oxidation in Alcaligenes faecalis  

NASA Astrophysics Data System (ADS)

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.

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

2003-05-01

354

Growth states of catalytic reaction networks exhibiting energy metabolism  

NASA Astrophysics Data System (ADS)

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.

Kondo, Yohei; Kaneko, Kunihiko

2011-07-01

355

Anaerobic treatment of food industry wastewaters  

SciTech Connect

Food industry effluents are characterized by high pollutional loads, high temperatures and contain rapidly degrading substances such as saccharides and starches. Basic features of anaerobic treatment processes are discussed. By comparison with conventional aerobic processes it is demonstrated that for the majority of food industry applications, anaerobic treatment processes may be the more cost-effective solution. In well-designed anaerobic systems, the energy value of the methane gas produced is more than the energy required to operate the facility. Aerobic treatment on the other hand requires the input of a large amount of air energy.

Oleszkiewicz, J.A.; Olthof, M.

1982-06-01

356

Anaerobic pretreatment of pharmaceutical wastewaters  

SciTech Connect

The US Department of Energy's (DOE) Office of Industrial Technologies (OIT) sponsors research and development (R D) to improve the energy efficiency of American industry and to provide for fuel flexibility. The pharmaceutical industry generates considerable amounts of wastewater that require extensive treatment before they are released. A common method of disposal is aerobic biological treatment, but this method is energy intensive and expensive. An alternative process--anaerobic digestion--costs less, saves energy, generates less sludge requiring disposal, and produces a usable fuel--methane. OIT and HydroQual, Inc., with Merck Co. recently completed a joint project that demonstrated the anaerobic biological treatment of wastewaters generated by the pharmaceutical industry. The objectives of the project were to demonstrate how the anaerobic biological process and the resulting energy savings can apply to the pharmaceutical industry and how effective and beneficial the process is to sludge management operations at pharmaceutical plants. This technical case study provides an overview of the DOE-HydroQual-Merck R D project and highlights the field tests done on pilot-scale anaerobic wastewater treatment units at a pharmaceutical plant. This document makes field test and data analysis results available to other researchers and private industry. It discusses project status; summarizes field-test efforts; and reviews potential technology impacts in terms of commercial applications, benefits, and full-scale system economics. 5 figs., 1 tab.

Not Available

1990-10-01

357

Pathways of energy conservation in methanogenic archaea  

Microsoft Academic Search

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

U. Deppenmeier; V. Müller; G. Gottschalk

1996-01-01

358

Microbiology and physiology of anaerobic fermentations of cellulose. Progress report.  

National Technical Information Service (NTIS)

The biochemistry and physiology of four major groups of anaerobic bacteria involved in the conversion of cellulose to methane or chemical feedstocks are examined. Aspects of metabolism which are relevant to the interactions and bioenergetics of consortia ...

J. Wiegel

1991-01-01

359

Response of anaerobic carbon cycling to water table manipulation ...  

Treesearch

Denitrification enzyme activity indicated a very high denitrification potential (197 ± 23 µg ... Dissolved organic carbon (DOC) concentrations were the strongest ... effectiveness of organic acids as substrates in anaerobic metabolism, would help  ...

360

Fermentation metabolism and its evolution in algae.  

PubMed

Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume. PMID:23734158

Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C; Grossman, Arthur R

2013-05-22

361

Fermentation metabolism and its evolution in algae  

PubMed Central

Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume.

Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C.; Grossman, Arthur R.

2013-01-01

362

Energiantuotanto turkistarhajaetteistae saatavalla biokaasulla. Loppuraportti. (Energy production from anaerobic treatment of the fur ranch wastes. Final report).  

National Technical Information Service (NTIS)

The feasibility of anaerobic treatment for fur farm wastes was studied by Soil and Water Ltd. in a farm owned by Farm Frys Ab. The pilot reactor, MABI, with a volume of 10 m(sup 3), was owned by Neste 0y. The amount of manure produced by fur-bearing anima...

K. Harmaa P Vaeaenaenen

1986-01-01

363

Feasibility and strategies for anaerobic digestion of solid waste for energy production in Dar es Salaam city, Tanzania  

Microsoft Academic Search

In Tanzania, the most serious solid waste management problem currently is disposal, but since the largest fraction of the waste is organics which are amenable to anaerobic digestion and composting, it makes environmental and economic sense to explore these options. This prompted the conception of the Taka (waste) Gas Project which is meant to utilise organic solid waste from Dar

Stephen E Mbuligwe; Gabriel R Kassenga

2004-01-01

364

Degradative capacities and bioaugmentation potential of an anaerobic benzene-degrading bacterium strain DN11  

SciTech Connect

Azoarcus sp. strain DN11 is a denitrifying bacterium capable of benzene degradation under anaerobic conditions. The present study evaluated strain DN11 for its application to bioaugmentation of benzene-contaminated underground aquifers. Strain DN11 could grow on benzene, toluene, m-xylene, and benzoate as the sole carbon and energy sources under nitrate-reducing conditions, although o- and p-xylenes were transformed in the presence of toluene. Phenol was not utilized under anaerobic conditions. Kinetic analysis of anaerobic benzene degradation estimated its apparent affinity and inhibition constants to be 0.82 and 11 {mu}M, respectively. Benzene-contaminated groundwater taken from a former coal-distillation plant site in Aichi, Japan was anaerobically incubated in laboratory bottles and supplemented with either inorganic nutrients (nitrogen, phosphorus, and nitrate) alone, or the nutrients plus strain DN11, showing that benzene was significantly degraded only when DN11 was introduced. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments, and quantitative PCR revealed that DN11 decreased after benzene was degraded. Following the decrease in DN11 16S rRNA gene fragments corresponding to bacteria related to Owenweeksia hongkongensis and Pelotomaculum isophthalicum, appeared as strong bands, suggesting possible metabolic interactions in anaerobic benzene degradation. Results suggest that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations. 50 refs., 6 figs., 1 tab.

Yuki Kasai; Yumiko Kodama; Yoh Takahata; Toshihiro Hoaki; Kazuya Watanabe [Marine Biotechnology Institute, Kamaishi (Japan)

2007-09-15

365

Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA  

SciTech Connect

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.

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

2006-04-05

366

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

SciTech Connect

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.

Goodwin, S.D.

1986-01-01

367

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

Microsoft Academic Search

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

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

2007-01-01

368

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  

Microsoft Academic Search

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

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

2006-01-01

369

Impact of Ocean Acidification on Energy Metabolism of Oyster, Crassostrea gigas--Changes in Metabolic Pathways and Thermal Response  

PubMed Central

Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Pörtner and Farrell [1], synergistic effects of elevated temperature and CO2-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO2 levels (partial pressure of CO2 in the seawater ~0.15 kPa, seawater pH ~ 7.7). Within one month of incubation at elevated Pco2 and 15 °C hemolymph pH fell (pHe = 7.1 ± 0.2 (CO2-group) vs. 7.6 ± 0.1 (control)) and Peco2 values in hemolymph increased (0.5 ± 0.2 kPa (CO2-group) vs. 0.2 ± 0.04 kPa (control)). Slightly but significantly elevated bicarbonate concentrations in the hemolymph of CO2-incubated oysters ([HCO? 3]e = 1.8 ± 0.3 mM (CO2-group) vs. 1.3 ± 0.1 mM (control)) indicate only minimal regulation of extracellular acid-base status. At the acclimation temperature of 15 °C the OA-induced decrease in pHe did not lead to metabolic depression in oysters as standard metabolism rates (SMR) of CO2-exposed oysters were similar to controls. Upon acute warming SMR rose in both groups, but displayed a stronger increase in the CO2-incubated group. Investigation in isolated gill cells revealed a similar temperaturedependence of respiration between groups. Furthermore, the fraction of cellular energy demand for ion regulation via Na+/K+-ATPase was not affected by chronic hypercapnia or temperature. Metabolic profiling using 1H-NMR spectroscopy revealed substantial changes in some tissues following OA exposure at 15 °C. In mantle tissue alanine and ATP levels decreased significantly whereas an increase in succinate levels was observed in gill tissue. These findings suggest shifts in metabolic pathways following OA-exposure. Our study confirms that OA affects energy metabolism in oysters and suggests that climate change may affect populations of sessile coastal invertebrates such as mollusks.

Lannig, Gisela; Eilers, Silke; Portner, Hans O.; Sokolova, Inna M.; Bock, Christian

2010-01-01

370

Deterioration of platelet energy metabolism following energy crisis of liver after hepatectomy.  

PubMed

The aim of this study is to investigate the relationship in energy metabolism between the platelet and the liver. The adenylate energy charge of human platelets and arterial ketone body ratio (AKBR:acetoacetate/3-hydroxybutyrate) were measured in 11 patients after hepatectomy. Hepatic energy crisis was defined as the decrease of AKBR below 0.7. The platelet energy charge was measured on the first (Day 1), the second (Day 2), third (Day 3) and sixth (Day 6) day during AKBR decreased and remained under 0.7. The values before AKBR decreased were employed as the control. The values of the platelet energy charge were 0.917 +/- 0.008 in the control (n = 11) and 0.896 +/- 0.009 in all samples after AKBR decreased under 0.7 (n = 30). There was no significant difference between them. The values of energy charge were divided into four groups according to the periods of time after AKBR decreased and remained under 0.7 and compared. The energy charge was 0.923 +/- 0.006 (Day 1, n = 11), 0.907 +/- 0.008 (Day 2, n = 10), 0.890 +/- 0.005 (Day 3, n = 5), and 0.815 +/- 0.012 (Day 6, n = 4). The energy charge of Day 3 was significantly lower than that of Day 1 (p < 0.01). The energy charge of Day 6 was significantly lower than that of Day 1, 2, 3 (p < 0.001, p < 0.001, and p < 0.01, respectively). The 4 patients whose AKBR remained under 0.7 for more than 6 days had hemostatic disorder. The deterioration of the platelet energy charge metabolism lags behind that of the liver.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7781647

Egawa, H; Zaima, M; Mori, K; Hiroshi, H; Iwata, S; Ozawa, K; Yamaoka, Y

1995-01-01

371

Differential anoxic expression of sugar-regulated genes reveals diverse interactions between sugar and anaerobic signaling systems in rice.  

PubMed

The interaction between the dual roles of sugar as a metabolic fuel and a regulatory molecule was unveiled by examining the changes in sugar signaling upon oxygen deprivation, which causes the drastic alteration in the cellular energy status. In our study, the expression of anaerobically induced genes is commonly responsive to sugar, either under the control of hexokinase or non-hexokinase mediated signaling cascades. Only sugar regulation via the hexokinase pathway was susceptible for O2 deficiency or energy deficit conditions evoked by uncoupler. Examination of sugar regulation of those genes under anaerobic conditions revealed the presence of multiple paths underlying anaerobic induction of gene expression in rice, subgrouped into three distinct types. The first of these, which was found in type-1 genes, involved neither sugar regulation nor additional anaerobic induction under anoxia, indicating that anoxic induction is a simple result from the release of sugar repression by O2-deficient conditions. In contrast, type-2 genes also showed no sugar regulation, albeit with enhanced expression under anoxia. Lastly, expression of type-3 genes is highly enhanced with sugar regulation sustained under anoxia. Intriguingly, the inhibition of the mitochondrial ATP synthesis can reproduce expression pattern of a specific set of anaerobically induced genes, implying that rice cells may sense O2 deprivation, partly via perception of the perturbed cellular energy status. Our study of interaction between sugar signaling and anaerobic conditions has revealed that sugar signaling and the cellular energy status are likely to communicate with each other and influence anaerobic induction of gene expression in rice. PMID:23852132

Lim, Mi-Na; Lee, Sung-Eun; Yim, Hui-Kyeong; Kim, Jeong Hoe; Yoon, In Sun; Hwang, Yong-Sic

2013-07-12

372

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

Microsoft Academic Search

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

Gottfried Unden

1998-01-01

373

Estrogen-related receptor gamma modulates energy metabolism target genes in human trophoblast.  

PubMed

Placenta growth and functions depend on correct trophoblast migration, proliferation, and differentiation. The placenta has a critical role in gas and nutrient transport. To accomplish these numerous functions, the placenta depends on a highly efficient energy metabolism control. Recent studies showed that the orphan nuclear receptor Estrogen-Related Receptor gamma (ERR?) is highly expressed in human placentas. As ERR? has been described as a major energy metabolism regulator, we investigated ERR? expression and putative roles on energy homeostasis in human trophoblast from first trimester placentas. First, we showed that ERR? expression level increased during pregnancy and that ERR? was more abundant in villous than in extravillous trophoblasts. We also observed that ERR? expression increased during trophoblast differentiation. Second, we demonstrated that mitochondrial biogenesis and expression of some energy metabolism target genes decreased when ERR? expression was impaired. Altogether, these results suggest that ERR? could be implicated in the energy metabolism regulation of human trophoblasts. PMID:22763271

Poidatz, D; Dos Santos, E; Brulé, A; De Mazancourt, P; Dieudonné, M N

2012-07-02

374

The Energetics of Aerobic versus Anaerobic Respiration.  

ERIC Educational Resources Information Center

|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)|

Champion, Timothy D.; Schwenz, Richard W.

1990-01-01

375

Metabolic costs of growth in free-living Garter Snakes and the energy budgets of ectotherms  

Microsoft Academic Search

Summary 1. The metabolic or respiratory cost of growth ( RG) is the increase in metabolic rate of a growing animal, and it represents chemical potential energy expended in support of net biosynthesis but not deposited as new tissue. 2. Two statistical methods (multiple non-linear regression and analysis of regression residuals) were used to calculate RG from data (n =

C. C. Peterson; B. M. Walton; A. F. Bennett

1999-01-01

376

Teaching Energy Metabolism Using Scientific Articles: Implementation of a Virtual Learning Environment for Medical Students  

ERIC Educational Resources Information Center

|This work describes the use of a virtual learning environment (VLE) applied to the biochemistry class for undergraduate, first-year medical students at the Federal University of Rio de Janeiro. The course focused on the integration of energy metabolism, exploring metabolic adaptations in different physiological or pathological states such as…

de Espindola, Marina Bazzo; El-Bacha, Tatiana; Giannella, Tais Rabetti; Struchiner, Miriam; da Silva, Wagner S.; Da Poian, Andrea T.

2010-01-01

377

Energy expenditure in Crocidurinae shrews (Insectivora): Is metabolism a key component of the insular syndrome?  

Microsoft Academic Search

A cascade of morphological, ecological, demographical and behavioural changes operates within island communities compared to mainland. We tested whether metabolic rates change on islands. Using a closed circuit respirometer, we investigated resting metabolic rate (RMR) of three species of Crocidurinae shrews: Suncus etruscus, Crocidura russula, and C. suaveolens. For the latter, we compared energy expenditure of mainland and island populations.

Elodie Magnanou; Roger Fons; Jacques Blondel; Serge Morand

2005-01-01

378

Metabolomics characterization of energy metabolism reveals glycogen accumulation in gut-microbiota-lacking mice  

Microsoft Academic Search

Microbiota in the gut are considered an important environmental factor associated with host metabolism and physiology. Although gut microbiota are known to contribute to hepatic lipogenesis and fat storage, little is known about how the condition influences the deposition of glycogen in the liver. To better understand and characterize the host energy metabolism in guts lacking microbiota, we compared the

Hsiao-Li Chuang; Yen-Te Huang; Chien-Chao Chiu; Chia-Ding Liao; Feng-Lin Hsu; Chi-Chang Huang; Chia-Chung Hou

379

Dry anaerobic fermentation  

Microsoft Academic Search

The advantages of using high total-solids concentrations for anaerobic fermentations of manures and crop residues are discussed. Studies conducted on dry anaerobic fermentation of organic residues to methane are described. Moisture content, NHâ-N concentration, and chloride concentration were tested. Anaerobic fermentations occurred in solids concentrations in excess of 20%. At initial concentrations of 40% or less, the reaction will be

W. J. Wujcik; W. J. Jewell

1980-01-01

380

Inhibition of anaerobic digestion process: a review.  

PubMed

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 applied. A wide variety of inhibitory substances are the primary cause of anaerobic digester upset or failure since they are present in substantial concentrations in wastes. Considerable research efforts have been made to identify the mechanism and the controlling factors of inhibition. This review provides a detailed summary of the research conducted on the inhibition of anaerobic processes. The inhibitors commonly present in anaerobic digesters include ammonia, sulfide, light metal ions, heavy metals, and organics. Due to the difference in anaerobic inocula, waste composition, and experimental methods and conditions, literature results on inhibition caused by specific toxicants vary widely. Co-digestion with other waste, adaptation of microorganisms to inhibitory substances, and incorporation of methods to remove or counteract toxicants before anaerobic digestion can significantly improve the waste treatment efficiency. PMID:17399981

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

2007-03-30

381

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

PubMed

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

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

2013-04-22

382

Anaerobic treatment as a core technology for energy, nutrients and water from source-separated domestic waste(water)  

Microsoft Academic Search

Based on results of pilot scale research with source-separated black water (BW) and grey water (GW), a new sanitation concept is proposed. BW and GW are both treated in a UASB (-septic tank) for recovery of CH4 gas. Kitchen waste is added to the anaerobic BW treatment for doubling the biogas production. Post-treatment of the effluent is providing recovery of

Grietje Zeeman; Katarzyna Kujawa; Mes de T. Z. D; Graaff de M. S; L. N. A. H. Abu-Ghunmi; A. R. Mels; B. Meulman; B. G. Temmink; C. J. N. Buisman; Lier van J. B; G. Lettinga

2008-01-01

383

Transgenic Mouse Models Resistant to Diet-Induced Metabolic Disease: Is Energy Balance the Key?  

PubMed Central

The prevalence and economic burden of obesity and type 2 diabetes is a driving force for the discovery of molecular targets to improve insulin sensitivity and glycemic control. Here, we review several transgenic mouse models that identify promising targets, ranging from proteins involved in the insulin signaling pathway, alterations of genes affecting energy metabolism, and transcriptional metabolic regulators. Despite the diverse endpoints in each model, a common thread that emerges is the necessity for maintenance of energy balance, suggesting pharmacotherapy must target the development of drugs that decrease energy intake, accelerate energy expenditure in a well controlled manner, or augment natural compensatory responses to positive energy balance.

Gilliam, Laura A. A.

2012-01-01

384

Effects of starvation and desiccation on energy metabolism in desert and mesic Drosophila.  

PubMed

Energy availability can limit the ability of organisms to survive under stressful conditions. In Drosophila, laboratory experiments have revealed that energy storage patterns differ between populations selected for desiccation and starvation. This suggests that flies may use different sources of energy when exposed to these stresses, but the actual substrates used have not been examined. We measured lipid, carbohydrate, and protein content in 16 Drosophila species from arid and mesic habitats. In five species, we measured the rate at which each substrate was metabolized under starvation or desiccation stress. Rates of lipid and protein metabolism were similar during starvation and desiccation, but carbohydrate metabolism was several-fold higher during desiccation. Thus, total energy consumption was lower in starved flies than desiccated ones. Cactophilic Drosophila did not have greater initial amounts of reserves than mesic species, but may have lower metabolic rates that contribute to stress resistance. PMID:12770001

Marron, M T; Markow, T A; Kain, K J; Gibbs, A G

2003-03-01

385

PET studies of brain energy metabolism in a model of subcortical dementia: Progressive Supranuclear Palsy.  

National Technical Information Service (NTIS)

In 41 patients with clinically determined Progressive Supranuclear Palsy, a model of degenerative subcortical dementia, alterations in regional brain energy metabolism with respect to control subjects have investigated using positron computed tomography a...

J. Blin J. C. Baron H. Cambon B. Dubois B. Pillon

1988-01-01

386

Effects of Wound Bacteria on Postburn Energy Metabolism.  

National Technical Information Service (NTIS)

This study identified the hypermetabolic and thermoregulatory effects of burn wound colonization and examined the role of endotoxin (LPS) in these responses. Resting metabolic rates and colonic temperatures (Tc) of 400-600 g. male Sprague-Dawley rats were...

L. H. Aulick

1988-01-01

387

Energy metabolism and hematology of white-tailed deer fawns  

USGS Publications Warehouse

Resting metabolic rates, weight gains and hematologic profiles of six newborn, captive white-tailed deer (Odocoileus virginianus) fawns (four females, two males) were determined during the first 3 mo of life. Estimated mean daily weight gain of fawns was 0.2 kg. The regression equation for metabolic rate was: Metabolic rate (kcal/kg0.75/day) = 56.1 +/- 1.3 (age in days), r = 0.65, P less than 0.001). Regression equations were also used to relate age to red blood cell count (RBC), hemoglobin concentration (Hb), packed cell volume, white blood cell count, mean corpuscular volume, mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin. The age relationships of Hb, MCHC, and smaller RBC's were indicative of an increasing and more efficient oxygen-carrying and exchange capacity to fulfill the increasing metabolic demands for oxygen associated with increasing body size.

Rawson, R.E.; DelGiudice, G.D.; Dziuk, H.E.; Mech, L.D.

1992-01-01

388

Influence of Metronidazole, CO, CO2, and Methanogens on the Fermentative Metabolism of the Anaerobic Fungus Neocallimastix sp. Strain L2  

PubMed Central

The effects of metronidazole, CO, methanogens, and CO2 on the fermentation of glucose by the anaerobic fungus Neocallimastix sp. strain L2 were investigated. Both metronidazole and CO caused a shift in the fermentation products from predominantly H2, acetate, and formate to lactate as the major product and caused a lower glucose consumption rate and cell protein yield. An increased lactate dehydrogenase activity and a decreased hydrogenase activity were observed in cells grown under both culture conditions. In metronidazole-grown cells, the amount of hydrogenase protein was decreased compared with the amount in cells grown in the absence of metronidazole. When Neocallimastix sp. strain L2 was cocultured with the methanogenic bacterium Methanobrevibacter smithii, the fermentation pattern changed in the opposite direction: H2 and acetate production increased at the expense of the electron sink products lactate, succinate, and ethanol. A concomitant decrease in the enzyme activities leading to these electron sink products was observed, as well as an increase in the glucose consumption rate and cell protein yield, compared with those of pure cultures of the fungus. Low levels of CO2 in the gas phase resulted in increased H2 and lactate formation and decreased production of formate, acetate, succinate, and ethanol, a decreased glucose consumption rate and cell protein yield, and a decrease in most of the hydrogenosomal enzyme activities. None of the tested culture conditions resulted in changed quantities of hydrogenosomal proteins. The results indicate that manipulation of the pattern of fermentation in Neocallimastix sp. strain L2 results in changes in enzyme activities but not in the proliferation or disappearance of hydrogenosomes. Images

Marvin-Sikkema, Femke D.; Rees, Elizabeth; Kraak, Marjan N.; Gottschal, Jan C.; Prins, Rudolf A.

1993-01-01

389

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

Microsoft Academic Search

The regulation of the human energy metabolism is crucial to ensure the functionality of the entire organism. Deregulations\\u000a may lead to severe pathologies such as diabetes mellitus and obesity. The decisive role of the brain as active controller\\u000a and heavy consumer in the complex whole-body energy metabolism is the object of recent research. Latest studies suggest the\\u000a priority of the

Britta Göbel; Dirk Langemann

2011-01-01

390

Pregnancy-related changes in activity energy expenditure and resting metabolic rate in Switzerland  

Microsoft Academic Search

Background\\/Objectives:To measure resting metabolic rate (RMR), activity energy expenditure (AEE), total energy expenditure (TEE) and physical activity pattern, that is, duration and intensity (in metabolic equivalents, METs) of activities performed in late pregnancy compared with postpartum in healthy, well-nourished women living in Switzerland.Subjects\\/Methods:Weight, height, RMR, AEE, TEE and physical activity patterns were measured longitudinally in 27 healthy women aged 23–40

K Melzer; Y Schutz; M Boulvain; B Kayser

2009-01-01

391

Characterization of anaerobic sulfite reduction by Salmonella typhimurium and purification of the anaerobically induced sulfite reductase  

SciTech Connect

Mutants of Salmonella typhimurium that lack the biosynthetic sulfite reductase (cysI and cysJ mutants) retain the ability to reduce sulfite for growth under anaerobic conditions. Here we report studies of sulfite reduction by a cysI mutant of S. typhimurium and purification of the associated anaerobic sulfite reductase. Sulfite reduction for anaerobic growth did not require a reducing atmosphere but was prevented by an argon atmosphere contaminated with air (<0.33%). It was also prevented by the presence of 0.1 mM nitrate. Anaerobic growth in liquid minimal medium, but not on agar, was found to require additions of trace amounts (10{sup {minus}7} M) of cysteine. Spontaneous mutants that grew under the argon contaminated with air also lost the requirement for 10{sup {minus}7}M cysteine for anaerobic growth in liquid. A role for sulfite reduction in anaerobic energy generation was contraindicated by the findings that sulfite reduction did not improve cell yields, and anaerobic sulfite reductase activity was greatest during the stationary phase of growth. Sulfite reductase was purified from the cytoplasmic fraction of the anaerobically grown cysI mutant and was purified 190-fold. The most effective donor in crude extracts was NADH. NADHP and methyl viologen were, respectively, 40 and 30% as effective as NADH. Oxygen reversibly inhibited the enzyme. The anaerobic sulfite reductase showed some resemblance to the biosynthetic sulfite reductase, but apparently it has a unique, as yet unidentified function.

Hallenbeck, P.C. (Universite de Montreal, Quebec (Canada)); Clark, M.A.; Barrett, E.L. (Univ. of California, Davis (USA))

1989-06-01

392

Assessing Risk Factors for Obesity Between Childhood and Adolescence: II. Energy Metabolism and Physical Activity  

Microsoft Academic Search

Objective. To assess the effect of energy expenditure, including resting metabolic rate (RMR), to- tal energy expenditure (TEE), and activity energy expen- diture (AEE), as well as substrate oxidation (respiratory quotient (RQ)), on the development of obesity in a large cohort of Native American children with a high propen- sity for obesity. Methods. During the summer months of 1992 to

Arline D. Salbe; Christian Weyer; Inge Harper; Robert S. Lindsay; Eric Ravussin; P. Antonio Tataranni

393

The TRH neuron: a hypothalamic integrator of energy metabolism.  

PubMed

Thyrotropin-releasing hormone (TRH) has an important role in the regulation of energy homeostasis not only through effects on thyroid function orchestrated through hypophysiotropic neurons in the hypothalamic paraventricular nucleus (PVN), but also through central effects on feeding behavior, thermogenesis, locomotor activation and autonomic regulation. Hypophysiotropic TRH neurons are located in the medial and periventricular parvocellular subdivisions of the PVN and receive direct monosynaptic projections from two, separate, populations of leptin-responsive neurons in the hypothalamic arcuate nucleus containing either alpha-melanocyte-stimulating hormone (alpha-MSH) and cocaine- and amphetamine-regulated transcript (CART), peptides that promote weight loss and increase energy expenditure, or neuropeptide Y (NPY) and agouti-related protein (AGRP), peptides that promote weight gain and reduce energy expenditure. During fasting, the reduction in TRH mRNA in hypophysiotropic neurons mediated by suppression of alpha-MSH/CART simultaneously with an increase in NPY/AGRP gene expression in arcuate nucleus neurons contributes to the fall in circulating thyroid hormone levels, presumably by increasing the sensitivity of the TRH gene to negative feedback inhibition by thyroid hormone. Endotoxin administration, however, has the paradoxical effect of increasing circulating levels of leptin and melanocortin signaling and CART gene expression in arcuate nucleus neurons, but inhibiting TRH gene expression in hypophysiotropic neurons. This may be explained by an overriding inhibitory effect of endotoxin to increase type 2 iodothyroine deiodinase (D2) in a population of specialized glial cells, tanycytes, located in the base and infralateral walls of the third ventricle. By increasing the conversion of T4 into T3, tanycytes may increase local tissue concenetrations of thyroid hormone, and thereby induce a state of local tissue hyperthyroidism in the region of hypophysisotrophic TRH neurons. Other regions of the brain may also serve as metabolic sensors for hypophysiostropic TRH neurons including the ventrolateral medulla and dorsomedial nucleus of the hypothalamus that have direct monosynaptic projections to the PVN. TRH also exerts a number of effects within the central nervous system that may contribute to the regulation of energy homeostasis. Included are an increase in core body temperature mediated through neurons in the anterior hypothalamic-preoptic area that coordinate a variety of autonomic responses; arousal and locomotor activation through cholinergic and dopaminergic mechanisms on the septum and nucleus accumbens, respectively; and regulation of the cephalic phase of digestion. While the latter responses are largely mediated through cholinergic mechanisms via TRH neurons in the brainstem medullary raphe and dorsal motor nucleus of the vagus, effects of TRH on autonomic loci in the hypothalamic PVN may also be important. Contrary to the actions of T3 to increase appetite, TRH has central effects to reduce food intake in normal, fasting and stressed animals. The precise locus where TRH mediates this response is unknown. However, evidence that an anatomically separate population of nonhypophysiotropic TRH neurons in the anterior parvocellular subdivision of the PVN is integrated into the leptin regulatory control system by the same arcuate nucleus neuronal populations that innervate hypophysiotropic TRH neurons, raises the possibility that anterior parvocellular TRH neurons may be involved, possibly through interactions with the limbic nervous system. PMID:16876577

Lechan, Ronald M; Fekete, Csaba

2006-01-01

394

Ethidium bromide efflux by Salmonella: modulation by metabolic energy, pH, ions and phenothiazines.  

PubMed

The main efflux pump of Salmonella enterica serotype Enteritidis, which obtains its energy for the extrusion of noxious agents from the proton-motive force, was studied with the aid of an ethidium bromide (EtBr) semi-automated method under conditions that define the role of metabolic energy, ions and pH in the extrusion of the universal substrate EtBr. The results obtained in this study indicate that in minimal medium containing sodium at pH 5 efflux of EtBr is independent of glucose, whereas at pH 8 metabolic energy is an absolute requirement for the maintenance of efflux. In deionised water at pH 5.5, metabolic energy is required for the maintenance of efflux. The inhibitory effect of the ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on efflux is shown to be minimised by low pH, and at high pH by metabolic energy. Similarly, thioridazine, an inhibitor of metabolic enzymes, inhibits efflux of EtBr only at pH 8 and the degree of inhibition is lessened by the presence of metabolic energy. PMID:21565465

Amaral, Leonard; Cerca, Pedro; Spengler, Gabriella; Machado, Lisa; Martins, Ana; Couto, Isabel; Viveiros, Miguel; Fanning, Séamus; Pagès, Jean-Marie

2011-05-11

395

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

PubMed

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

Göbel, Britta; Langemann, Dirk

2010-08-24

396

Upflow anaerobic sludge blanket reactor--a review.  

PubMed

Biological treatment of wastewater basically reduces the pollutant concentration through microbial coagulation and removal of non-settleable organic colloidal solids. Organic matter is biologically stabilized so that no further oxygen demand is exerted by it. The biological treatment requires contact of the biomass with the substrate. Various advances and improvements in anaerobic reactors to achieve variations in contact time and method of contact have resulted in development of in suspended growth systems, attached growth or fixed film systems or combinations thereof. Although anaerobic systems for waste treatment have been used since late 19th century, they were considered to have limited treatment efficiencies and were too slow to serve the needs of a quickly expanding wastewater volume, especially in industrialized and densely populated areas. At present aerobic treatment is the most commonly used process to reduce the organic pollution level of both domestic and industrial wastewaters. Aerobic techniques, such as activated sludge process, trickling filters, oxidation ponds and aerated lagoons, with more or less intense mixing devices, have been successfully installed for domestic wastewater as well as industrial wastewater treatment. Anaerobic digestion systems have undergone modifications in the last two decades, mainly as a result of the energy crisis. Major developments have been made with regard to anaerobic metabolism, physiological interactions among different microbial species, effects of toxic compounds and biomass accumulation. Recent developments however, have demonstrated that anaerobic processes might be an economically attractive alternative for the treatment of different types of industrial wastewaters and in (semi-) tropical areas also for domestic wastewaters. The anaerobic degradation of complex, particulate organic matter has been described as a multistep process of series and parallel reactions. It involves the decomposition of organic and inorganic matter in the absence of molecular oxygen. Complex polymeric materials such as polysaccharides, proteins, and lipids (fat and grease) are first hydrolyzed to soluble products by extracellular enzymes, secreted by microorganisms, so as to facilitate their transport or diffusion across the cell membrane. These relatively simple, soluble compounds are fermented or anaerobically oxidized, further to short-chain fatty acids, alcohols, carbon dioxide, hydrogen, and ammonia. The short-chain fatty acids (other than acetate) are converted to acetate, hydrogen gas, and carbon dioxide. Methanogenesis finally occurs from the reduction of carbon dioxide and acetate by hydrogen. The initial stage of anaerobic degradation, i.e. acid fermentation is essentially a constant BOD stage because the organic molecules are only rearranged. The first stage does not stabilize the organics in the waste. However this step is essential for the initiation of second stage methane fermentation as it converts the organic material to a form, usable by the methane producing bacteria. The second reaction is initiated when anaerobic methane forming bacteria act upon the short chain organic acids produced in the 1st stage. Here these acids undergo methane fermentation with carbon dioxide acting as hydrogen acceptor and getting reduced to methane. The methane formed, being insoluble in water, escapes from the system and can be tapped and used as an energy source. The production and subsequent escape of methane causes the stabilization of the organic material. The methane-producing bacteria consist of several different groups. Each group has the ability to ferment only specific compounds. Therefore, the bacterial consortia in a methane producing system should include a number of different groups. When the rate of bacterial growth is considered, then the retention time of the solids becomes important parameter. The acid fermentation stage is faster as compared to the methane fermentation stage. This means that a sudden increase in the easily degradable organics will result in increased acid

Bal, A S; Dhagat, N N

2001-04-01

397

The Drosophila 7-pass transmembrane glycoprotein BOSS and metabolic regulation: What Drosophila can teach us about human energy metabolism.  

PubMed

Glucose is a key carbohydrate for the majority of living organisms. In animals, plasma glucose levels must be strictly regulated and maintained at proper levels. Abnormal upregulated glucose levels lead to various human metabolic disorders such as diabetes or obesity. In the diabetic state, protein glycation occurs, producing nonenzymatic products that are thought to be causative compounds for the disease. During evolution, animals developed sensing and regulatory mechanisms to maintain constant levels of body glucose levels. How organisms respond to extracellular glucose and how glucose controls nutrient homeostasis, however, have remained uncertain. Recently, we identified bride of sevenless (BOSS) in Drosophila as a glucose-responding membrane receptor. In this chapter, we summarize the utility of Drosophila as a model organism for studying conserved mechanisms of glucose and triacylglycerol (energy) homeostatic metabolism through the 7-pass transmembrane glycoprotein BOSS, which carries N-linked carbohydrates. PMID:20816226

Kohyama-Koganeya, Ayako; Hirabayashi, Yoshio

2010-01-01

398

Linking energy metabolism to dysfunctions in mitochondrial respiration--a metabolomics in vitro approach.  

PubMed

The study presented here describes the application of metabolite profiling of highly polar, intracellular metabolites after incubation of a mammalian fibroblast cell line with inhibitors of mitochondrial function. A metabolomics approach was used to assess the complex response of the cellular energy metabolism. Metabolic profiles of phosphorylated and carboxylated intracellular metabolites were assessed by UPLC-MS/MS and used to predict the mode of mitochondrial toxicity. Based on distinct metabolic patterns, multivariate data analysis allowed for the discrimination of two groups of toxins: inhibitors of the electron transport in mitochondrial membranes (complex IV inhibitors) and uncouplers of oxidative phosphorylation. Beyond these known interferences, metabolic profiling was able to reveal additional inhibitory effects on the cellular energy metabolism. Most prominently, for three of the toxins, metabolic patterns also disclosed an enhanced activity of the glycerol phosphate shuttle inferring the inhibition of NADH dehydrogenase at complex I. Secondly, inhibition of the electron transport was accompanied by a limiting availability of citric acid cycle intermediates and aspartate. Concomitantly, specific perturbations of the purine nucleotide cycle were observed. We have shown here that metabolomic approaches may assist to predict complex modes of action of toxic compounds on cellular level as well as to unravel specific dysfunctions in the energy metabolism. PMID:21402135

Balcke, G U; Kolle, S N; Kamp, H; Bethan, B; Looser, R; Wagner, S; Landsiedel, Robert; van Ravenzwaay, B

2011-03-23

399

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

PubMed

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

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

2011-10-17