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The Equilibria existing between Succinic, Fumaric, and Malic Acids in the presence of Resting Bacteria.

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... The reactions brought about by the organism under these conditions we consider to be reactions produced by the resting organism. The term resting organism as we have defined it is useful for comparison with resting muscle and other tissues" [8]. With reference to an NGMA cell bioproduction process, two or three separate phases are distinguished: (I) a cell production phase, (II) a bioconversion phase and, depending on the requirements, (III) a phase in which cultivation conditions can be modified so that the growth rate of the microorganism decreases, in between phase (I) and (II) [9]. ...
... The NGMA cell process was by early definition associated with high cell densities [8]. Until an optimal value, fast and productive conversion may benefit from increased catalyst concentrations in the bioconversion broth. ...
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Micro-organisms are often subjected to stressful conditions. Owing to their capacity to adapt, they try to rapidly cope with the unfavorable conditions by lowering their growth rate, changing their morphology, and developing altered metabolite production and other stress-related metabolism. The stress-related metabolism of the cells which interrupted their growth is often referred to as resting metabolism and can be exploit for specific and high rate production of secondary metabolites. Although the bacterial resting cell process has been described decades ago, we find it worthwhile to bring the process under renewed attention and refer to this type of processes as non-growing metabolically active (NGMA) cell processes. Despite their use may sound counterproductive, NGMA cells can be of interest to increase substrate conversion rates or enable conversion of certain substrates, not accessible to growing cells due to their bacteriostatic nature or requirement of resistance to a multitude of different stress mechanisms. Biomass reuse is an interesting feature to improve the economics of NGMA cell processes. Yet, for lipophilic compounds or compounds with low solubility, biomass separation can be delicate. This review draws the attention on existing examples of NGMA cell processes, summarizing some developmental tools and highlighting drawbacks and opportunities, to answer the research question if NGMA cells can have a distinct added value in industry. Particular elaboration is made on a novel and more broadly applicable strategy to enable biomass reuse for conversions of compounds with low solubility.
... The ability of whole cells of E. coli to reversibly oxidize succinate to fumarate has been recognized for more than 75 years [5]. Some three decades later it was shown that puri¢ed preparations of mammalian succinate dehydrogenase, in addition to catalyzing succinate oxidation, are also capable of fumarate reduction [6]. ...
... The QFR structures and the high degree of similarity of E. coli SQR to its mammalian counterparts will allow experimentalists to manipulate the E. coli enzymes to provide insights into the function of complex II in mammals. Thus 75 years after the ¢rst observation of an equilibrium between succinic and fumaric acids in E. coli [5] complex II from this organism continues to be an excellent model for our understanding of this fascinating membrane-bound protein complex. ...
Article
Succinate-ubiquinone oxidoreductase (SQR) as part of the trichloroacetic acid cycle and menaquinol-fumarate oxidoreductase (QFR) used for anaerobic respiration by Escherichia coli are structurally and functionally related membrane-bound enzyme complexes. Each enzyme complex is composed of four distinct subunits. The recent solution of the X-ray structure of QFR has provided new insights into the function of these enzymes. Both enzyme complexes contain a catalytic domain composed of a subunit with a covalently bound flavin cofactor, the dicarboxylate binding site, and an iron-sulfur subunit which contains three distinct iron-sulfur clusters. The catalytic domain is bound to the cytoplasmic membrane by two hydrophobic membrane anchor subunits that also form the site(s) for interaction with quinones. The membrane domain of E. coli SQR is also the site where the heme b556 is located. The structure and function of SQR and QFR are briefly summarized in this communication and the similarities and differences in the membrane domain of the two enzymes are discussed.
... If we write for the equation oxidized blue dye + reduced red dye = oxidized red dye + reduced blue dye, then Since at pH 6.59 the El0 of naphtholsulfonate indo-2,6-dichlorophenol is +0.151 volt (Clark), we must subtract 0.06 log,, 1 Pure cytochrome C was isolated from beef heart muscle by the excellent method of Keilin and Hartree (8). It contained 0.342 per cent Fe determined by the method of Lintzel (9) modified to the extent of measuring the pink Fe ++-bipyridine complex spectrophotometrically at X = 5200 A. Calculation of the concentration of one of our solutions of cytochrome by this method and by the spectrophotometric method (equation given by Keilin and Hartree (8)) agreed perfectly. ...
Article
This paper deals with the relation between substrate concentration and velocity in the case of the reduction of methylene blue and of the other oxidation-reduction indicators of Clark by B. coli in the presence of succinic acid and glucose. This system is compared with starch and barley amylase. Reasons are given for considering the mechanism as an adsorption phenomenon.
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1. The purple sulphur bacteria are able to develop in media containing only one simple, nitrogen-free organic compound, in the absence of oxidizable sulphur compounds. 2. Radiant energy is indispensable for development in these media. 3. A quantitative chemical investigation has been carried out of the metabolism in cultures containing lactate, pyruvate, acetate, succinate, malate or butyrate as the organic substrate. 4. In these cultures practically no metabolic products other than relatively small amounts of CO2 have been detected; in the butyrate cultures CO2 is taken up instead of being formed. 5. By determining the carbon content of the bacterial substance synthesized in the cultures, it has been shown that in all probability the substrate is completely converted into cell material and CO2, i. o. w. that the assimilation predominates in the metabolism. 6. The differences in the amount of CO2 formed (or taken up) per unit of substrate consumed in cultures with different substrates are caused by the different oxidation values of the various substrates, the average oxidation value of the cell material of the bacteria being approximately the same with all substrates. 7. Since a consideration of assimilation in general leads to the insight that the greater majority of organic cell constituents is formed from the substrate via pyruvic acid, the ways in which this acid can be formed from the various substrates used in the experiments have been discussed. 8. The conversion of the substrate into pyruvic acid involves one or more dehydrogenations; a consideration of the hydrogen acceptors which may effect this dehydrogenation shows that CO2 must play a prominent part as an acceptor in this process. 9. In connection with point 2 this leads to the conclusion that photosynthetic processes are involved in the metabolism of the purple sulphur bacteria in organic media. 10. In the equation for photosynthesis in general: \textCO\text2 \text + \text2H\text2 \textA ® \textCH\text2 \textO \text + \text2A \text + \textH\text2 \textO{\text{CO}}_{\text{2}} {\text{ + }} {\text{2H}}_{\text{2}} {\text{A}} \to {\text{CH}}_{\text{2}} {\text{O}} {\text{ + }} {\text{2A}} {\text{ + }} {\text{H}}_{\text{2}} {\text{O}} H2A may now be replaced by organic substances as well as by H2S or H2O.
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In vergleichenden Untersuchungen mit verschiedenen Methoden zur histochemischen Darstellung der Succinodehydrase wird festgestellt, daß Untersuchungen an Gewebsblöcken wenig geeignet sind und der Nachweis am unfixierten Gefrierschnitt eine gute Darstellbarkeit der Succinodehydrase ergibt. Als geeignete und verhältnismäßig einfach zu handhabende Methode wird eine vereinfachende Modifikation des Verfahrens vonRutenburg, Wolman undSeligman 1953 angegeben, die bei einem pH von 7,6 (Phosphatpuffer mit Zusatz von 0,2% KCN) reproduzierbare Bilder ergibt, die mit der guten Originalmethode übereinstimmen.
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The antibacterial nitrofuran, Furacin (5-nitro-2-furaldehyde semicarbazone), was shown to have a marked inhibition on the rate of reduction of methylene blue, Nile blue A, and triphenyltetrazolium chloride by washed Escherichia coli cells in the presence of a variety of substrates. Methylene blue, once reduced, cannot be reoxidized by Furacin, and the inhibition of its reduction has been interpreted as a competition with Furacin for the hydrogen mobilized by the dehydrogenases. The leuco form of Nile blue A can be reoxidized by Furacin, and the complex inhibition of its reduction is an expression of this reoxidation with Furacin acting as a hydrogen acceptor. An interesting interaction of redox indicators was revealed in that indigo carmine can be reduced only through the action of reduced Nile blue A serving as carrier.
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When confronted with a dermatomyositis or polymyositis patient not responding to immunosuppressive treatment, physicians must first ask whether the original diagnosis was correct. In this review, we provide a guide to the clinical features and ancillary tests, which might be helpful in the differential diagnosis of myositis. Particular attention is paid to the role of autoantibody detection, as some of them are not only relatively specific for the disease but also associated with unique clinical features including resistance to treatment. Subsequently, other possible explanations of treatment resistance are listed and a short overview of treatment options for resistant myositis patients is given.
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1. The term "coupled redox potential" is defined. 2. The system lactic ion See PDF for Equation pyruvic ion + 2H(+) + 2e is shown to be reversible (when the enzyme is lactic acid dehydrogenase) and its coupled redox potential between pH 5.2 and 7.2 at 32 degrees C. is: See PDF for Equation 3. The free energy of the reaction: lactic ion (1m) --> pyruvic ion (1m) = -DeltaF = -14,572. 4. The standard free energy of formation (DeltaF(298)) of pyruvic acid (l) is estimated at -108,127. This is merely an approximation as some necessary data are lacking. 5. The importance of coupled redox potentials as a factor in the regulation of the equilibrium of metabolites is indicated.
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1. The tissues of Rous chicken sarcoma and of the infectious myxoma of the rabbit do not possess the oxidation-reduction enzyme succinodehydrogenase, which is present in normal tissues and in transplantable tumors. 2. Filterable virus diseases (rabbit Virus III, rabbit neurovaccine, rabbit herpes, fowl-pox) produce in the tissues affected by them a partial inhibition of succinodehydrogenase.
Article
1. The critical thermal increments are calculated for respiratory processes (O(2) consumption, CO(2) production) in various plants and animals. They are characteristically found to be of two, possibly three, types: micro = 11,500, and 16,100 or 16,700. The first is commonly encountered above 15 degrees , the second below that temperature, but these relations may be reversed. (The value of micro may be significantly changed in inanition.) 2. For reduction of methylene blue by bacteria, through removal of H from succinic acid, micro = 16,700. This process (Quastel and Whetham, 1924) at constant temperature is a function of the hydroxyl ion concentration. The suggestive identity is pointed out of the critical increment for this reduction phenomenon with that deduced for biological respirations in which a dehydrogenation mechanism is supposed to be of widespread occurrence, and in connection with which Fe very likely has a catalytic rôle. The action of OH' is believed to be revealed in the value micro = 11,500, frequently obtained in connection with respiration. 3. A somewhat lower micro (16,140) is associated with the oxidation of Fe'', and may be compared with (1) that of respiration in sea urchin eggs, for which (Warburg) iron is catalyst, and (2) that for some simple reactions in which Fe is known to serve as catalyst; it is not found for oxidative reactions in which Fe is not involved. 4. The bearing of these findings is discussed in relation to the theory of functional analysis of concurrent catalyzed reactions in protoplasm. It is shown that for a number of activities in which the effects of respiration may safely be assumed, the values of the critical increments are consistent with those determined for processes of respiration. 5. The further development of these views may lead to an extremely important method of identifying controlling reactions in undisturbed living matter.
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Mild agitation of bovine epididymal spermatozoa in the presence of 75- or 85-μ diameter glass beads alters the cells to permit the observation of a large increase of net Pi uptake and respiration with a concomitant increase in P:O ratios to near-theoretical values. The uptake of organic dye, loss of nucleotides, protein, the acrosome, and motility, with no gross anatomical change in sperm morphology, suggest that only the cell membranes were modified by the bead treatment. The cofactor requirements and other environmental parameters affecting oxidative phosphorylation were defined. Bead treatment of bovine-ejaculated spermatozoa depressed respiration and only occasionally enhanced P:O ratios. The cell membranes of bovine epididymal spermatozoa were also modified by exposure to hypotonic solutions for brief periods. This produced a slight depression in respiration but a significant elevation in the observed efficiency of oxidative phosphorylation. The validity of the methods developed in these reports to measure oxidative phosphorylation is discussed.
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While animal eggs await fertilization, their cell cycle needs to be halted. The molecule responsible for this arrest ? the cytostatic factor ? was first described in 1971. But its identity was not revealed until 1989, and even now questions remain about this elusive factor.
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Everyone who has ever taken biology at school has heard of the Krebs cycle, but few realize that Hans Krebs also discovered two other cycles. It is appropriate, at the centenary of his birth, to consider the circumstances and experiments that led Krebs to establish these metabolic pathways.
IntroductionSuccinic Dehydrogenase and Succinic Oxidase PreparationsGeneral Properties of Succinic DehydrogenaseOn the Existence of Unidirectional Fumaric ReductasesEvaluation of Significance of Particulate Units and Soluble Preparations in Succinate Oxidation
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Dasinger, B. L. (University of Wisconsin, Madison) and J. B. Wilson. Glutamate metabolism in Brucella abortus strains of low and high virulence. J. Bacteriol. 84 911–915. 1962.—Brucella abortus strains of low virulence oxidize glutamate at a high rate, whereas strains of high virulence oxidize glutamate at a relatively low rate. Results indicated that this observation was not related to differences in pathway of glutamate oxidation or to differences in total enzyme activity. Permeability studies showed that the maximal rates of glutamate accumulation were 2.8 μmoles per 2 min per g (wet wt) for a strain of high virulence and 6.2 μmoles per 2 min per g for a strain of low virulence, but equal intracellular steady-state concentrations were attained by both types of strains. Evidence is presented which suggests that the site of glutamate oxidation is separate from the pool of glutamate being measured. Unequal rates of permeability at these sites could be the reason for the differences in rate of glutamate oxidation.
Chapter
Experimental FindingsReaction Schemes (Theory of Carbohydrate Oxidation)Problems Related to the Oxidation of Carbohydrate
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Chapter
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Chapter
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Chapter
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Chapter
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Summary The strain ofEsch. coli has been made resistant to Stylomycin and Viomycin, wherein there is slight fall in the oxidizing power of glucose in case of Stylomycin and nearly no change in Viomycin resistant culture when compared with the oxidising power of normal culture.
Article
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Potentiometric titrations of iron-sulfur proteins monitored by changes in circular dichroism (CD) or electron-paramagnetic-resonance (EPR) spectrum are presented. Both monitoring techniques have the distinct advantage that interferences caused by the absorption changes of the redox mediators during a titration, which limit the use of the absorption spectrophotometry for monitoring, are either not monitored, or do not represent a serious interference. The CD tritration is illustrated with soluble spinach ferrodoxin and the EPR titration with bound iron-sulfur proteins of green plant photosystem I.The anacrobic titration apparatus and other experimental considerations are described in detail.
Article
Die Monohalogenbernsteinsäuren, nicht dagegen die beiden Dibrombernsteinsäuren, sind Substrate der Succinodehydrase; Brom- und besonders Jodbernsteinsäure zeigen Optima der Substraktonzentration. Die Halogenbernsteinsäuren vermögen andrerseits die Succinatdehydrierung zu hemmen; meso-Dibrombernsteinsäure < Brombernsteinsäure < Jodbernsteinsäure. Für Brom und Jodbernsteinsäure wurde die kompetitive Natur der Hemmung nachgewiesen. Bei höherer Konzentration kann sich eine „Inkubationshemmung” in der Art der Jodessigsäurehemmung von Sulfhydryl-Enzymen überlagern; doch erreicht die Jodsuccinathemmung nur etwa die Hälfte der Jodacetathemmung. Die aerobe Succinatdehydrierung wird durch Halogensuccinat stärker gehemmt als die aerobe, was auf eine nichtkompetitive Hemmung der Indophenol- bzw. Cytochromoxydase zurückgeführt werden konnte. — In einer Carboxylgruppe substituierte Bernsteinsäuren werden nicht dehydriert, ebenso wenig Methoxy-, Acetoxy- und Acetylaminobernsteinsäure. Die kompetitive Hemmungsgröße einer Anzahl von Bernsteinsäure- und Malonsäure-Derivaten wurde vergleichend nach der THUNBERG-Methodik gemessen. Die wirksamsten Inhibitoren sind Oxalessigsäure und — eine Größenordnung abwärts — Malonsäure. Beträchtliche Hemmungen zeigen unter den Bernsteinsäure-Derivaten noch Fumarsäure ap; Itakonsäure > Acetylendicarbonsäure > Mesoweinsäure, unter den Malonsäure-Derivaten Mesoxalsäure > Chlormalonsäure > Brommalonsäure. Einführung von Halogen < Methyl < Äthyl < Hydroxyl schwächt die Inhibitorwirkung der Malonsäure in gleicher Reihenfolge wie die Donatorwikung der Bernsteinsäure.
Ber. deutsch. chem. Gem. 35, 700
Einbeck (1919).. Biochem. Z. 95, 296. Emmerling and Reiser (1902). Ber. deutsch. chem. Gem. 35, 700. Hopkins and Dixon (1922). J. Biol. Chem. 54, 527. Ohlsson (1921). Skand. Arch. Phy8iol. 41, 77. Quastel (1924). Biochem. J. 18, 365.
for his continual interest and encouragement in this work. The thanks of one of us (M.D.W.) are due to the Medical Research Council for a part time grant
  • F G Prof
  • F R S Hopkins
We wish to offer our sincerest thanks to Prof. F. G. Hopkins, F.R.S., for his continual interest and encouragement in this work. The thanks of one of us (M.D.W.) are due to the Medical Research Council for a part time grant. REFERENCES.
  • Dakin
Dakin (1922). J. BioL Chem. 52, 183.