Interference of a short-chain phospholipid with ion transport pathways in frog skin

DEFF Research Database (Denmark)

Unmack, M A; Frederiksen, O; Willumsen, N J

1997-01-01

The effects of mucosal application of the short-chain phospholipid didecanoyl-L-alpha-phosphatidylcholine (DDPC; with two saturated 10-carbon acyl chains) on active Na+ transport and transepithelial conductance (G) in the frog skin (Rana temporaria) were investigated. Active Na+ transport...... of the frog skin epithelium and opens a paracellular tight junction pathway. Both effects may be caused by incorporation of DDPC in the apical cell membrane....

Fatty Acyl Chains of Mycobacterium marinum Lipooligosaccharides

Science.gov (United States)

Rombouts, Yoann; Alibaud, Laeticia; Carrère-Kremer, Séverine; Maes, Emmanuel; Tokarski, Caroline; Elass, Elisabeth; Kremer, Laurent; Guérardel, Yann

2011-01-01

We have recently established the fine structure of the glycan backbone of lipooligosaccharides (LOS-I to LOS-IV) isolated from Mycobacterium marinum, a close relative of Mycobacterium tuberculosis. These studies culminated with the description of an unusual terminal N-acylated monosaccharide that confers important biological functions to LOS-IV, such as macrophage activation, that may be relevant to granuloma formation. It was, however, also suggested that the lipid moiety was required for LOSs to exert their immunomodulatory activity. Herein, using highly purified LOSs from M. marinum, we have determined through a combination of mass spectrometric and NMR techniques, the structure and localization of the fatty acids composing the lipid moiety. The occurrence of two distinct polymethyl-branched fatty acids presenting specific localizations is consistent with the presence of two highly related polyketide synthases (Pks5 and Pks5.1) in M. marinum and presumably involved in the synthesis of these fatty acyl chains. In addition, a bioinformatic search permitted us to identify a set of enzymes potentially involved in the biosynthesis or transfer of these lipids to the LOS trehalose unit. These include MMAR_2343, a member of the Pap (polyketide-associated protein) family, that acylates trehalose-based glycolipids in M. marinum. The participation of MMAR_2343 to LOS assembly was demonstrated using a M. marinum mutant carrying a transposon insertion in the MMAR_2343 gene. Disruption of MMAR_2343 resulted in a severe LOS breakdown, indicating that MMAR_2343, hereafter designated PapA4, fulfills the requirements for LOS acylation and assembly. PMID:21803773

Concentrations of long-chain acyl-acyl carrier proteins during fatty acid synthesis by chloroplasts isolated from pea (Pisum sativum), safflower (Carthamus tinctoris), and amaranthus (Amaranthus lividus) leaves

International Nuclear Information System (INIS)

Roughan, G.; Nishida, I.

1990-01-01

Fatty acid synthesis from [1-14C]acetate by chloroplasts isolated from peas and amaranthus was linear for at least 15 min, whereas incorporation of the tracer into long-chain acyl-acyl carrier protein (ACP) did not increase after 2-3 min. When reactions were transferred to the dark after 3-5 min, long-chain acyl-ACPs lost about 90% of their radioactivity and total fatty acids retained all of theirs. Half-lives of the long-chain acyl-ACPs were estimated to be 10-15 s. Concentrations of palmitoyl-, stearoyl-, and oleoyl-ACP as indicated by equilibrium labeling during steady-state fatty acid synthesis, ranged from 0.6-1.1, 0.2-0.7, and 0.4-1.6 microM, respectively, for peas and from 1.6-1.9, 1.3-2.6, and 0.6-1.4 microM, respectively, for amaranthus. These values are based on a chloroplast volume of 47 microliters/mg chlorophyll and varied according to the mode of the incubation. A slow increase in activity of the fatty acid synthetase in safflower chloroplasts resulted in long-chain acyl-ACPs continuing to incorporate labeled acetate for 10 min. Upon re-illumination following a dark break, however, both fatty acid synthetase activity and acyl-ACP concentrations increased very rapidly. Palmitoyl-ACP was present at concentrations up to 2.5 microM in safflower chloroplasts, whereas those of stearoyl- and oleoyl-ACPs were in the lower ranges measured for peas. Acyl-ACPs were routinely separated from extracts of chloroplasts that had been synthesising long-chain fatty acids from labeled acetate by a minor modification of the method of Mancha et al. The results compared favorably with those obtained using alternative analytical methods such as adsorption to filter paper and partition chromatography on silicic acid columns

Tissue carnitine homeostasis in very-long-chain acyl-CoA dehydrogenase-deficient mice

NARCIS (Netherlands)

Spiekerkoetter, Ute; Tokunaga, Chonan; Wendel, Udo; Mayatepek, Ertan; Ijlst, Lodewijk; Vaz, Frederic M.; van Vlies, Naomi; Overmars, Henk; Duran, Marinus; Wijburg, Frits A.; Wanders, Ronald J.; Strauss, Arnold W.

2005-01-01

Deficiency of very-long-chain acyl-CoA dehydrogenase (VLCAD) is the most common long-chain fatty acid oxidation defect and presents with heterogeneous clinical manifestations. Accumulation of long-chain acylcarnitines and deficiency of free carnitine have often been proposed to play an important

Long-chain acyl-CoA-dependent regulation of gene expression in bacteria, yeast and mammals

DEFF Research Database (Denmark)

Black, P N; Færgeman, Nils J.; DiRusso, C C

2000-01-01

). Both repression and activation are dependent upon the function of either of the acyl-CoA synthetases Faa1p or Faa4p. In mammals, purified hepatocyte nuclear transcription factor 4alpha (HNF-4alpha) like E. coli FadR, binds long chain acyl-CoA directly. Coexpression of HNF-4alpha and acyl-CoA synthetase...

Very long-chain acyl-coenzyme A dehydrogenase deficiency

Directory of Open Access Journals (Sweden)

A. V. Degtyareva

2014-01-01

Full Text Available The paper describes a case of a baby with a severe infant form of very long-chain acyl-coenzyme A dehydrogenase deficiency, a very rare genetic disorder. The basis for the disease is a disorder of mitochondrial β-oxidation of long-chain fatty acids. Accumulation of acyl-CoA-derived fatty acids causes a toxic effect on the myocardium and cardiac conduction system, liver, skeletal muscles, and other organs. The development of hypoglycemia is typical. Treatment in the acute period involves the immediately ceased delivery of long-chain triglycerides, the provision of the body with medium-chain triglycerides, and the correction of glycemia. In our observation the baby was born at term with a satisfactory condition in a family with a poor history (the first baby had suddenly died at the age of 3,5 months. The disease manifested itself as bradyarrhythmia and cardiac arrest on day 2 of life. The clinical symptom complex also included hepatomegalia, hypoglycemic episodes, lactate acidosis, and elevated blood levels of cytolytic enzymes and creatine phosphokinase. The diagnosis was suspected on the basis of the high blood values of acylcarnitines (primarily C14:1 and verified by a molecular genetic examination. Syndrome therapy and dietotherapy resulted in the abolishment of the abnormality. At the age of 2 years of life, the infant’s physical, motor, mental, and speech development corresponded to his age although he had mild right-sided hemiparesis. Thus, timely therapy determines the favorable prognosis of the disease even in its severe infant forms. 

Hydrolysis of short-chain phosphatidylcholines by bee venom phospholipase A2.

Science.gov (United States)

Raykova, D; Blagoev, B

1986-01-01

In order to find out the aggregation state of the substrate, preferred by bee venom phospholipase A2 (EC 3.1.1.4), its action on short-chain phosphatidylcholines with two identical (C6-C10) fatty acids has been tested. The rate of hydrolysis as a function of acyl chain length showed a maximum at dioctanoylphosphatidylcholine. The effects of alcohols, NaCl and Triton X-100, which affect the aggregation state of phospholipids in water, were also studied. The addition of n-alcohol led to a significant inhibition of the hydrolysis of the substrates present in micellar form and activated the hydrolysis of substrates which form liposomes. The inhibitory effect increased with increasing length of the aliphatic carbon chain of the alcohol. Triton X-100 at low Triton/phospholipid molar ratios enhanced enzyme activity. These results do not agree with the accepted idea that bee venom phospholipase A2 hydrolyzes short-chain lecithins in their molecularly dispersed form and that micelles cannot act as substrates. The data indicate that short-chain lecithins in the aggregated state are hydrolyzed and that the requirements of bee venom phospholipase A2 for the aggregation state of the substrate are not strict.

Crystallization of the C-terminal domain of the mouse brain cytosolic long-chain acyl-CoA thioesterase

International Nuclear Information System (INIS)

Serek, Robert; Forwood, Jade K.; Hume, David A.; Martin, Jennifer L.; Kobe, Bostjan

2006-01-01

The C-terminal domain of the mouse long-chain acyl-CoA thioesterase has been expressed in bacteria and crystallized by vapour diffusion. The crystals diffract to 2.4 Å resolution. The mammalian long-chain acyl-CoA thioesterase, the enzyme that catalyses the hydrolysis of acyl-CoAs to free fatty acids, contains two fused 4HBT (4-hydroxybenzoyl-CoA thioesterase) motifs. The C-terminal domain of the mouse long-chain acyl-CoA thioesterase (Acot7) has been expressed in bacteria and crystallized. The crystals were obtained by vapour diffusion using PEG 2000 MME as precipitant at pH 7.0 and 290 K. The crystals have the symmetry of space group R32 (unit-cell parameters a = b = 136.83, c = 99.82 Å, γ = 120°). Two molecules are expected in the asymmetric unit. The crystals diffract to 2.4 Å resolution using the laboratory X-ray source and are suitable for crystal structure determination

Long Chain N-acyl Homoserine Lactone Production by Enterobacter sp. Isolated from Human Tongue Surfaces

Science.gov (United States)

Yin, Wai-Fong; Purmal, Kathiravan; Chin, Shenyang; Chan, Xin-Yue; Chan, Kok-Gan

2012-01-01

We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4), suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL). To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium. PMID:23202161

An insight on acyl migration in solvent-free ethanolysis of model triglycerides using Novozym 435.

Science.gov (United States)

Sánchez, Daniel Alberto; Tonetto, Gabriela Marta; Ferreira, María Luján

2016-02-20

In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20mg), reaction time (30-90min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase. Copyright © 2016 Elsevier B.V. All rights reserved.

Clear correlation of genotype with disease phenotype in very-long-chain acyl-CoA dehydrogenase deficiency

DEFF Research Database (Denmark)

Andresen, B S; Olpin, S; Poorthuis, B J

1999-01-01

Very-long-chain acyl-CoA dehydrogenase (VLCAD) catalyzes the initial rate-limiting step in mitochondrial fatty acid beta-oxidation. VLCAD deficiency is clinically heterogenous, with three major phenotypes: a severe childhood form, with early onset, high mortality, and high incidence of cardiomyop......Very-long-chain acyl-CoA dehydrogenase (VLCAD) catalyzes the initial rate-limiting step in mitochondrial fatty acid beta-oxidation. VLCAD deficiency is clinically heterogenous, with three major phenotypes: a severe childhood form, with early onset, high mortality, and high incidence...... of cardiomyopathy; a milder childhood form, with later onset, usually with hypoketotic hypoglycemia as the main presenting feature, low mortality, and rare cardiomyopathy; and an adult form, with isolated skeletal muscle involvement, rhabdomyolysis, and myoglobinuria, usually triggered by exercise or fasting......-phenotype relationship is in sharp contrast to what has been observed in medium-chain acyl-CoA dehydrogenase deficiency, in which no correlation between genotype and phenotype can be established....

Biosynthesis of triacylglycerols containing very long chain monounsaturated acyl moieties in developing seeds

International Nuclear Information System (INIS)

Fehling, E.; Murphy, D.J.; Mukherjee, K.D.

1990-01-01

Particulate (15,000g) fractions from developing seeds of honesty (Lunaria annua L.) and mustard (Sinapis alba L.) synthesize radioactive very long chain monounsaturated fatty acids (gadoleic, erucic, and nervonic) from [1- 14 C]oleoyl-CoA and malonyl-CoA or from oleoyl-CoA and [2- 14 C]malonyl-CoA. The very long chain monounsaturated fatty acids are rapidly channeled to triacylglycerols and other acyl lipids without intermediate accumulation of their CoA thioesters. When [1- 14 C]oleoyl-CoA is used as the radioactive substrate, phosphatidylcholines and other phospholipids are most extensively radiolabeled by oleoyl moieties rather than by very long chain monounsaturated acyl moieties. When [2- 14 C]malonyl-CoA is used as the radioactive substrate, no radioactive oleic acid is formed and the newly synthesized very long chain monounsaturated fatty acids are extensively incorporated into phosphatidylcholines and other phospholipids as well as triacylglycerols. The pattern of labeling of the key intermediates of the Kennedy pathway, e.g. lysophosphatidic acids, phosphatidic acids, and diacylglycerols by the newly synthesized very long chain monounsaturated fatty acids is consistent with the operation of this pathway in the biosynthesis of triacylglycerols

Glycosphingolipids: 2H NMR study of the influence of carbohydrate headgroup structure on ceramide acyl chain behavior in glycolipid-phospholipid bilayers

International Nuclear Information System (INIS)

Fenske, D.B.; Jarrell, H.C.; Hamilton, K.; Florio, E.; Barber, K.R.; Grant, C.W.M.

1991-01-01

Galactosyl- and glucosylceramide, globoside, and dihydrolactosylceramide, bearing [2,2- 2 H 2 ]stearic acid, have been studied at a concentration of 10 mol % in bilayers of dimyristoylphosphatidylcholine by 2 H NMR. The quadrupolar splittings Δv Q of the C2 deuterons were measured at several temperatures in the range of 30-60 degree C. Spin-lattice relaxation times T 1 of C2 deuterons were determined in the same temperature range for all lipids but globoside. T 1 values for the GlcCer and GalCer systems increased with temperature, indicating that the motions responsible for relaxation were in the short correlation time regime. T 1 for deuterons at the acyl chain C2-position of LaCer was observed to decrease with increasing temperature, indicating that the motion(s) dominating relaxation are in the long correlation time regime. Thus the mobility of the acyl chain at the 2-position is reduced in the LacCer with respect to GlcCer and GalCer

Ethylene glycol causes acyl chain disordering in liquid-crystalline, unsaturated phospholipid model membranes, as measured by 2H NMR

International Nuclear Information System (INIS)

Nicolay, K.; Kruijff, B. de; Smaal, E.B.

1986-01-01

2 H NMR has been used to probe the effects of ethylene glycol at the level of the acyl chains in liposomes prepared from dioleoylphosphatidic acid or dioleoylphosphatidylcholine, labeled with 2 H at the 11-position of both oleic acid chains. Increasing concentrations of ethylene glycol lead to a proportional and substantial decrease in the quadrupolar splittings, measured from the 2 H NMR spectra of both liposomal system, indicative of acyl chain disordering. (Auth.)

Long-chain Acyl-CoA is not increased in Myotubes established from Type 2 Diabetic Subjects

DEFF Research Database (Denmark)

Just, Malene; Faergeman, Nils J; Knudsen, Jens

2006-01-01

Accumulation of intramuscular long-chain acyl-CoA esters (LCACoA) has previously in animal and human models been suggested to play an important role in lipid induced insulin resistance. The aim of this study was to examine whether myotubes established from type 2 diabetic (T2D) subjects and lean...... controls express differences in long-chain acyl-CoA esters (LCACoA) precultured under physiological conditions and during chronic exposure to palmitate (PA) and oleic acids (OA) with/without acute insulin stimulation. No significant differences were found between diabetic and control myotubes, neither...

Two Predicted Transmembrane Domains Exclude Very Long Chain Fatty acyl-CoAs from the Active Site of Mouse Wax Synthase.

Directory of Open Access Journals (Sweden)

Steffen Kawelke

Full Text Available Wax esters are used as coatings or storage lipids in all kingdoms of life. They are synthesized from a fatty alcohol and an acyl-CoA by wax synthases. In order to get insights into the structure-function relationships of a wax synthase from Mus musculus, a domain swap experiment between the mouse acyl-CoA:wax alcohol acyltransferase (AWAT2 and the homologous mouse acyl-CoA:diacylglycerol O-acyltransferase 2 (DGAT2 was performed. This showed that the substrate specificity of AWAT2 is partially determined by two predicted transmembrane domains near the amino terminus of AWAT2. Upon exchange of the two domains for the respective part of DGAT2, the resulting chimeric enzyme was capable of incorporating up to 20% of very long acyl chains in the wax esters upon expression in S. cerevisiae strain H1246. The amount of very long acyl chains in wax esters synthesized by wild type AWAT2 was negligible. The effect was narrowed down to a single amino acid position within one of the predicted membrane domains, the AWAT2 N36R variant. Taken together, we provide first evidence that two predicted transmembrane domains in AWAT2 are involved in determining its acyl chain length specificity.

Intracellular long-chain acyl CoAs activate TRPV1 channels.

Directory of Open Access Journals (Sweden)

Yi Yu

Full Text Available TRPV1 channels are an important class of membrane proteins that play an integral role in the regulation of intracellular cations such as calcium in many different tissue types. The anionic phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2 is a known positive modulator of TRPV1 channels and the negatively charged phosphate groups interact with several basic amino acid residues in the proximal C-terminal TRP domain of the TRPV1 channel. We and other groups have shown that physiological sub-micromolar levels of long-chain acyl CoAs (LC-CoAs, another ubiquitous anionic lipid, can also act as positive modulators of ion channels and exchangers. Therefore, we investigated whether TRPV1 channel activity is similarly regulated by LC-CoAs. Our results show that LC-CoAs are potent activators of the TRPV1 channel and interact with the same PIP2-binding residues in TRPV1. In contrast to PIP2, LC-CoA modulation of TRPV1 is independent of Ca2+i, acting in an acyl side-chain saturation and chain-length dependent manner. Elevation of LC-CoAs in intact Jurkat T-cells leads to significant increases in agonist-induced Ca2+i levels. Our novel findings indicate that LC-CoAs represent a new fundamental mechanism for regulation of TRPV1 channel activity that may play a role in diverse cell types under physiological and pathophysiological conditions that alter fatty acid transport and metabolism such as obesity and diabetes.

Methylobacterium extorquens AM1 produces a novel type of acyl-homoserine lactone with a double unsaturated side chain under methylotrophic growth conditions.

Science.gov (United States)

Nieto Penalver, Carlos G; Morin, Danièle; Cantet, Franck; Saurel, Olivier; Milon, Alain; Vorholt, Julia A

2006-01-23

Acyl-homoserine lactones (acyl-HSLs) have emerged as important regulatory molecules for many gram-negative bacteria. We have found that Methylobacterium extorquens AM1, a member of the pink-pigmented facultative methylotrophs commonly present on plant surfaces, produces several acyl-HSLs depending upon the carbon source. A novel HSL was discovered with a double unsaturated carbon chain (N-(tetradecenoyl)) (C14:2) and characterized by MS and proton NMR. This long-chain acyl-HSL is synthesized by MlaI that also directs synthesis of C14:1-HSL. The Alphaproteobacterium also produces N-hexanoyl-HSL (C6-HSL) and N-octanoyl-HSL (C8-HSL) via MsaI.

Glycosphingolipids: sup 2 H NMR study of the influence of carbohydrate headgroup structure on ceramide acyl chain behavior in glycolipid-phospholipid bilayers

Energy Technology Data Exchange (ETDEWEB)

Fenske, D.B.; Jarrell, H.C. (National Research Council of Canada, Ottawa, Ontario (Canada)); Hamilton, K.; Florio, E.; Barber, K.R.; Grant, C.W.M. (Univ. of Western Ontario, London (Canada))

1991-05-07

Galactosyl- and glucosylceramide, globoside, and dihydrolactosylceramide, bearing (2,2-{sup 2}H{sub 2})stearic acid, have been studied at a concentration of 10 mol % in bilayers of dimyristoylphosphatidylcholine by {sup 2}H NMR. The quadrupolar splittings {Delta}v{sub Q} of the C2 deuterons were measured at several temperatures in the range of 30-60{degree}C. Spin-lattice relaxation times T{sub 1} of C2 deuterons were determined in the same temperature range for all lipids but globoside. T{sub 1} values for the GlcCer and GalCer systems increased with temperature, indicating that the motions responsible for relaxation were in the short correlation time regime. T{sub 1} for deuterons at the acyl chain C2-position of LaCer was observed to decrease with increasing temperature, indicating that the motion(s) dominating relaxation are in the long correlation time regime. Thus the mobility of the acyl chain at the 2-position is reduced in the LacCer with respect to GlcCer and GalCer.

Checks and balances in membrane phospholipid class and acyl chain homeostasis, the yeast perspective

NARCIS (Netherlands)

de Kroon, A.I.P.M.|info:eu-repo/dai/nl/084765283; Rijken, P.J.|info:eu-repo/dai/nl/32716297X; De Smet, C.H.|info:eu-repo/dai/nl/304824224

2013-01-01

Glycerophospholipids are the most abundant membrane lipid constituents in most eukaryotic cells. As a consequence, phospholipid class and acyl chain homeostasis are crucial for maintaining optimal physical properties of membranes that in turn are crucial for membrane function. The topic of this

Purification, crystallization and preliminary crystallographic analysis of very-long-chain acyl-CoA dehydrogenase from Caenorhabditis elegans

International Nuclear Information System (INIS)

Li, Zhijie; Zhai, Yujia; Fang, Junnan; Zhou, Qiangjun; Geng, Yunqi; Sun, Fei

2010-01-01

Very-long-chain acyl-CoA dehydrogenase from Caenorhabditis elegans (cVLCAD) has been crystallized in space group C2 and its X-ray diffraction data set has been collected to 1.6 Å resolution. Unlike other VLCADs that were reported to form dimers, the purified cVLCAD was found as a homotetrameric protein according to static light-scattering measurements. Acyl-CoA dehydrogenase [acyl-CoA:(acceptor) 2,3-oxidoreductase; EC 1.3.99.3] catalyzes the first reaction step in mitochondrial fatty-acid β-oxidation. Here, the very-long-chain acyl-CoA dehydrogenase from Caenorhabditis elegans (cVLCAD) has been cloned and overexpressed in Escherichia coli strain BL21 (DE3). Interestingly, unlike other very-long-chain acyl-CoA dehydrogenases, cVLCAD was found to form a tetramer by size-exclusion chromatography coupled with in-line static light-scattering, refractive-index and ultraviolet measurements. Purified cVLCAD (12 mg ml −1 ) was successfully crystallized by the hanging-drop vapour-diffusion method under conditions containing 100 mM Tris–HCl pH 8.0, 150 mM sodium chloride, 200 mM magnesium formate and 13% PEG 3350. The crystal has a tetragonal form and a complete diffraction data set was collected and processed to 1.8 Å resolution. The crystal belonged to space group C2, with unit-cell parameters a = 138.6, b = 116.7, c = 115.3 Å, α = γ = 90.0, β = 124.0°. A self-rotation function indicated the existence of one noncrystallographic twofold axis. A preliminary molecular-replacement solution further confirmed the presence of two molecules in one asymmetric unit, which yields a Matthews coefficient V M of 2.76 Å 3 Da −1 and a solvent content of 55%

Acyl-CoA metabolism and partitioning

DEFF Research Database (Denmark)

Grevengoed, Trisha J; Klett, Eric L; Coleman, Rosalind A

2014-01-01

Long-chain fatty acyl-coenzyme As (CoAs) are critical regulatory molecules and metabolic intermediates. The initial step in their synthesis is the activation of fatty acids by one of 13 long-chain acyl-CoA synthetase isoforms. These isoforms are regulated independently and have different tissue...

Polymorphism in 'L' shaped lipids: structure of N-, O-diacylethanolamines with mixed acyl chains.

Science.gov (United States)

Tarafdar, Pradip K; Swamy, Musti J

2009-11-01

Although solid state polymorphism in lipids has been established by spectroscopic and calorimetric studies long ago, only in a few cases crystal structures of different polymorphs of the same compound have been reported, possibly due to difficulties in obtaining high quality single crystals of individual polymorphs. Recent studies show that N-, O-diacylethanolamines (DAEs) can be derived by the O-acylation of the stress-related lipids, the N-acylethanolamines under physiological conditions. In this study, two DAEs with mixed acyl chains, namely N-palmitoyl, O-octanoylethanolamine and N-palmitoyl, O-decanoylethanolamine have been synthesized and their three-dimensional structures were determined. Both the compounds were found to adopt 'L' shaped structures and exist in two polymorphic forms, alpha and beta. In the alpha form a mixed-type chain packing has been observed whereas in the beta form the chain packing is symmetric. Similar polymorphic forms are likely to exist in other 'L' shaped lipids such as 1,3-diacylglycerols and ceramides, where polymorphism has been detected earlier, but three-dimensional structures - which can give precise information about the packing at atomic resolution - have not been reported.

A severe genotype with favourable outcome in very long chain acyl-CoA dehydrogenase deficiency

DEFF Research Database (Denmark)

Touma, E H; Rashed, M S; Vianey-Saban, C

2001-01-01

A patient with very long chain acyl-CoA dehydrogenase (VLCAD) deficiency is reported. He had a severe neonatal presentation and cardiomyopathy. He was found to be homozygous for a severe mutation with no residual enzyme activity. Tandem mass spectrometry on dried blood spots revealed increased lo...... chain acylcarnitines. VLCAD enzyme activity was severely decreased to 2% of control levels. Dietary management consisted of skimmed milk supplemented with medium chain triglycerides and L-carnitine. Outcome was good and there was no acute recurrence....

Regulation of lipolytic activity by long-chain acyl-coenzyme A in islets and adipocytes

DEFF Research Database (Denmark)

Hu, Liping; Deeney, Jude T; Nolan, Christopher J

2005-01-01

-cells. The mechanisms by which lipolysis is regulated in different tissues is, therefore, of considerable interest. Here, the effects of long-chain acyl-CoA esters (LC-CoA) on lipase activity in islets and adipocytes were compared. Palmitoyl-CoA (Pal-CoA, 1-10 microM) stimulated lipase activity in islets from both....... The inhibitory effect of LC-CoA on adipocyte HSL was dependent on phosphorylation and enhanced by acyl-CoA-binding protein (ACBP). In contrast, the stimulatory effect on islet lipase activity was blocked by ACBP, presumably due to binding and sequestration of LC-CoA. These data suggest the following intertissue...

Purification and characterization of an amidohydrolase for N4-long-chain fatty acyl derivatives of 1-beta-D-arabinofuranosylcytosine from mouse liver microsomes.

Science.gov (United States)

Hori, K; Tsuruo, T; Tsukagoshi, S; Sakurai, Y

1984-03-01

N4-Long-chain fatty acyl-1-beta-D-arabinofuranosylcytosine amidohydrolase, a metabolizing enzyme for N4-acyl derivatives of 1-beta-D-arabinofuranosylcytosine with long-chain fatty acids, was purified from mouse liver microsomes. The purification was accomplished by solubilization of liver microsomes with Triton X-100, diethylaminoethyl cellulose chromatography, gel filtrations, hydroxyapatite chromatography, and concanavalin A:Sepharose chromatography. On sodium dodecyl sulfate:polyacrylamide gel electrophoresis, the purified enzyme preparation produced a single protein band with a molecular weight of 54,000. The enzyme had an optimal pH of 9.0, and the Michaelis constant for N4-palmitoyl-1-beta-D-arabinofuranosylcytosine was 67 microM. The thiols such as dithiothreitol or 2-mercaptoethanol stabilized the enzyme and stimulated its activity. p-Chloromercuribenzoate, N-ethylmaleimide, diisopropylfluorophosphate, and phenylmethylsulfonyl fluoride strongly inhibited the reaction. Bovine serum albumin markedly stimulated the enzyme activity, whereas detergents such as Triton X-100, deoxycholate, and sodium dodecyl sulfate had little effect. The enzyme did not require monovalent or divalent cations. Among the series of N4-acyl derivatives of 1-beta-D-arabinofuranosylcytosine with different chain lengths of acyl residues, the purified enzyme preferentially hydrolyzed the derivatives with long-chain fatty acids (C12 to C18), and N4-palmitoyl-1-beta-D-arabinofuranosylcytosine was the most susceptible. The purified enzyme was inactive on various N-acylamino acids, amides, oligopeptides, proteins, N-acylsphingosines (ceramides), triglyceride, lecithin, and lysolecithin. These results suggest that N4-long-chain fatty acyl-1-beta-D-arabinofuranosylcytosine amidohydrolase may be a new type of linear amidase.

Plasma fatty acyl-carnitines during 8 Weeks of overfeeding: relation to diet energy expenditure and body composition: the PROOF study.

Science.gov (United States)

Bray, George A; Redman, Leanne M; de Jonge, Lilian; Rood, Jennifer; Sutton, Elizabeth F; Smith, Steven R

2018-01-24

Overfeeding is a strategy for evaluating the effects of excess energy intake. In this secondary analysis we tested the possibility that different levels of dietary protein might differentially modify the response of fatty acyl-carnitines to overfeeding. Twenty-three healthy adult men and women were overfed by 40% for 8 weeks while in-patients with diets containing 5% (LPD), 15% (NPD) or 25% (HPD) protein. Plasma fatty acyl-carnitines were measured by gas chromatography/mass spectrometry (GC/MS) at baseline and after 8 weeks of overfeeding. Measurements included: body composition by DXA, energy expenditure by ventilated hood and doubly-labeled water, fat cell size from subcutaneous fat biopsies, and fat distribution by CT scan. Analysis was done on 5 groups of fatty acyl-carnitines identified by principal components analysis and 6 individual short-chain fatty acyl carnitines. Higher protein intake was associated with significantly lower 8 week levels of medium chain fatty acids and C2, C4-OH and C 6:1, but higher values of C3 and C5:1 acyl-carnitines derived from essential amino acids. In contrast energy and fat intake were only weakly related to changes in fatty acyl-carnitines. A decease or smaller rise in 8 week medium chain acyl-carnitines was associated with an increase in sleeping energy expenditure (P = 0.0004), and fat free mass (P < 0.0001) and a decrease in free fatty acid concentrations (FFA) (P = 0.0067). In contrast changes in short-chain fatty acyl-carnitines were related to changes in resting energy expenditure (P = 0.0026), and fat free mass (P = 0.0007), and C4-OH was positively related to FFA (P = 0006). Protein intake was the major factor influencing changes in fatty acyl carnitines during overfeeding with higher values of most acyl-fatty acids on the low protein diet. The association of dietary protein and fat intake may explain the changes in energy expenditure and metabolic variables resulting in the observed

Understanding Acyl Chain and Glycerolipid Metabolism in Plants

Energy Technology Data Exchange (ETDEWEB)

Ohlrogge, John B.

2013-11-05

Progress is reported in these areas: acyl-editing in initial eukaryotic lipid assembly in soybean seeds; identification and characterization of two Arabidopsis thaliana lysophosphatidyl acyltransferases with preference for lysophosphatidylethanolamine; and characterization and subcellular distribution of lysolipid acyl transferase activity of pea leaves.

Acquired multiple Acyl-CoA dehydrogenase deficiency in 10 horses with atypical myopathy.

Science.gov (United States)

Westermann, C M; Dorland, L; Votion, D M; de Sain-van der Velden, M G M; Wijnberg, I D; Wanders, R J A; Spliet, W G M; Testerink, N; Berger, R; Ruiter, J P N; van der Kolk, J H

2008-05-01

The aim of the current study was to assess lipid metabolism in horses with atypical myopathy. Urine samples from 10 cases were subjected to analysis of organic acids, glycine conjugates, and acylcarnitines revealing increased mean excretion of lactic acid, ethylmalonic acid, 2-methylsuccinic acid, butyrylglycine, (iso)valerylglycine, hexanoylglycine, free carnitine, C2-, C3-, C4-, C5-, C6-, C8-, C8:1-, C10:1-, and C10:2-carnitine as compared with 15 control horses (12 healthy and three with acute myopathy due to other causes). Analysis of plasma revealed similar results for these predominantly short-chain acylcarnitines. Furthermore, measurement of dehydrogenase activities in lateral vastus muscle from one horse with atypical myopathy indeed showed deficiencies of short-chain acyl-CoA dehydrogenase (0.66 as compared with 2.27 and 2.48 in two controls), medium-chain acyl-CoA dehydrogenase (0.36 as compared with 4.31 and 4.82 in two controls) and isovaleryl-CoA dehydrogenase (0.74 as compared with 1.43 and 1.61 nmol min(-1) mg(-1) in two controls). A deficiency of several mitochondrial dehydrogenases that utilize flavin adenine dinucleotide as cofactor including the acyl-CoA dehydrogenases of fatty acid beta-oxidation, and enzymes that degrade the CoA-esters of glutaric acid, isovaleric acid, 2-methylbutyric acid, isobutyric acid, and sarcosine was suspected in 10 out of 10 cases as the possible etiology for a highly fatal and prevalent toxic equine muscle disease similar to the combined metabolic derangements seen in human multiple acyl-CoA dehydrogenase deficiency also known as glutaric acidemia type II.

Acyl chains of phospholipase D transphosphatidylation products in Arabidopsis cells: a study using multiple reaction monitoring mass spectrometry.

Directory of Open Access Journals (Sweden)

Dominique Rainteau

Full Text Available BACKGROUND: Phospholipases D (PLD are major components of signalling pathways in plant responses to some stresses and hormones. The product of PLD activity is phosphatidic acid (PA. PAs with different acyl chains do not have the same protein targets, so to understand the signalling role of PLD it is essential to analyze the composition of its PA products in the presence and absence of an elicitor. METHODOLOGY/PRINCIPAL FINDINGS: Potential PLD substrates and products were studied in Arabidopsis thaliana suspension cells treated with or without the hormone salicylic acid (SA. As PA can be produced by enzymes other than PLD, we analyzed phosphatidylbutanol (PBut, which is specifically produced by PLD in the presence of n-butanol. The acyl chain compositions of PBut and the major glycerophospholipids were determined by multiple reaction monitoring (MRM mass spectrometry. PBut profiles of untreated cells or cells treated with SA show an over-representation of 160/18:2- and 16:0/18:3-species compared to those of phosphatidylcholine and phosphatidylethanolamine either from bulk lipid extracts or from purified membrane fractions. When microsomal PLDs were used in in vitro assays, the resulting PBut profile matched exactly that of the substrate provided. Therefore there is a mismatch between the acyl chain compositions of putative substrates and the in vivo products of PLDs that is unlikely to reflect any selectivity of PLDs for the acyl chains of substrates. CONCLUSIONS: MRM mass spectrometry is a reliable technique to analyze PLD products. Our results suggest that PLD action in response to SA is not due to the production of a stress-specific molecular species, but that the level of PLD products per se is important. The over-representation of 160/18:2- and 16:0/18:3-species in PLD products when compared to putative substrates might be related to a regulatory role of the heterogeneous distribution of glycerophospholipids in membrane sub-domains.

How Chain Length and Charge Affect Surfactant Denaturation of Acyl Coenzyme A Binding Protein (ACBP)

DEFF Research Database (Denmark)

Andersen, Kell Kleiner; Otzen, Daniel

2009-01-01

maltoside (DDM). The aim has been to determine how surfactant chain length and micellar charge affect the denaturation mechanism. ACBP denatures in two steps irrespective of surfactant chain length, but with increasing chain length, the potency of the denaturant rises more rapidly than the critical micelle......Using intrinsic tryptophan fluorescence, equilibria and kinetics of unfolding of acyl coenzyme A binding protein (ACBP) have been investigated in sodium alkyl sulfate surfactants of different chain length (8-16 carbon atoms) and with different proportions of the nonionic surfactant dodecyl...... constants increases linearly with denaturant concentration below the cmc but declines at higher concentrations. Both shortening chain length and decreasing micellar charge reduce the overall kinetics of unfolding and makes the dependence of unfolding rate constants on surfactant concentration more complex...

Altered Energetics of Exercise Explain Risk of Rhabdomyolysis in Very Long-Chain Acyl-CoA Dehydrogenase Deficiency

NARCIS (Netherlands)

Diekman, E. F.; Visser, G.; Schmitz, J. P. J.; Nievelstein, R. A. J.; de Sain-van der Velden, M.; Wardrop, M.; van der Pol, W. L.; Houten, S. M.; van Riel, N. A. W.; Takken, T.; Jeneson, J. A. L.

2016-01-01

Rhabdomyolysis is common in very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) and other metabolic myopathies, but its pathogenic basis is poorly understood. Here, we show that prolonged bicycling exercise against a standardized moderate workload in VLCADD patients is associated with

Patients with medium-chain acyl-coenzyme a dehydrogenase deficiency have impaired oxidation of fat during exercise but no effect of L-carnitine supplementation

DEFF Research Database (Denmark)

Madsen, K L; Preisler, N; Orngreen, M C

2013-01-01

It is not clear to what extent skeletal muscle is affected in patients with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD). l-Carnitine is commonly used as a supplement in patients with MCADD, although its beneficial effect has not been verified.......It is not clear to what extent skeletal muscle is affected in patients with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD). l-Carnitine is commonly used as a supplement in patients with MCADD, although its beneficial effect has not been verified....

Molecular characterization of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency

DEFF Research Database (Denmark)

Gregersen, N; Andresen, B S; Bross, P

1991-01-01

. All clones sequenced from the patient exhibited a single base substitution from adenine (A) to guanine (G) at position 985 in the MCAD cDNA as the only consistent base-variation compared with control cDNA. In contrast, the parents contained cDNA with the normal and the mutated sequence, revealing......A series of experiments has established the molecular defect in the medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) gene in a family with MCAD deficiency. Demonstration of intra-mitochondrial mature MCAD indistinguishable in size (42.5-kDa) from control MCAD, and of mRNA with the correct...... size of 2.4 kb, indicated a point-mutation in the coding region of the MCAD gene to be disease-causing. Consequently, cloning and DNA sequencing of polymerase chain reaction (PCR) amplified complementary DNA (cDNA) from messenger RNA of fibroblasts from the patient and family members were performed...

Abnormal mitochondrial bioenergetics and heart rate dysfunction in mice lacking very-long-chain acyl-CoA dehydrogenase

NARCIS (Netherlands)

Exil, VJ; Gardner, CD; Rottman, JN; Sims, H; Bartelds, B; Khuchua, Z; Sindhal, R; Ni, GM; Strauss, AW

Mitochondrial very-long-chain acyl-CoA dehydrogenase ( VLCAD) deficiency is associated with severe hypoglycemia, cardiac dysfunction, and sudden death in neonates and children. Sudden death is common, but the underlying mechanisms are not fully understood. We report on a mouse model of VLCAD

The domain-specific and temperature-dependent protein misfolding phenotype of variant medium-chain acyl-CoA dehydrogenase

NARCIS (Netherlands)

Jank, Johanna M.; Maier, Esther M.; Reiβ, Dunja D.; Haslbeck, Martin; Kemter, Kristina F.; Truger, Marietta S.; Sommerhoff, Christian P.; Ferdinandusse, Sacha; Wanders, Ronald J.; Gersting, Søren W.; Muntau, Ania C.

2014-01-01

The implementation of expanded newborn screening programs reduced mortality and morbidity in medium-chain acyl-CoA dehydrogenase deficiency (MCADD) caused by mutations in the ACADM gene. However, the disease is still potentially fatal. Missense induced MCADD is a protein misfolding disease with a

Fluxomic evidence for impaired contribution of short-chain acyl-CoA dehydrogenase to mitochondrial palmitate β-oxidation in symptomatic patients with ACADS gene susceptibility variants.

Science.gov (United States)

Dessein, Anne-Frédérique; Fontaine, Monique; Joncquel-Chevalier Curt, Marie; Briand, Gilbert; Sechter, Claire; Mention-Mulliez, Karine; Dobbelaere, Dries; Douillard, Claire; Lacour, Arnaud; Redonnet-Vernhet, Isabelle; Lamireau, Delphine; Barth, Magalie; Minot-Myhié, Marie-Christine; Kuster, Alice; de Lonlay, Pascale; Gregersen, Niels; Acquaviva, Cécile; Vianey-Saban, Christine; Vamecq, Joseph

2017-08-01

Despite ACADS (acyl-CoA dehydrogenase, short-chain) gene susceptibility variants (c.511C>T and c.625G>A) are considered to be non-pathogenic, encoded proteins are known to exhibit altered kinetics. Whether or not, they might affect overall fatty acid β-oxidation still remains, however, unclear. De novo biosynthesis of acylcarnitines by whole blood samples incubated with deuterated palmitate (16- 2 H 3 ,15- 2 H 2 -palmitate) is suitable as a fluxomic exploration to distinguish between normal and disrupted β-oxidation, abnormal profiles and ratios of acylcarnitines with different chain-lengths being indicative of the site for enzymatic blockade. Determinations in 301 control subjects of ratios between deuterated butyrylcarnitine and sum of deuterated C2 to C14 acylcarnitines served here as reference values to state specifically functional SCAD impairment in patients addressed for clinical and/or biological suspicion of a β-oxidation disorder. Functional SCAD impairment was found in 39 patients. The 27 patients accepting subsequent gene studies were all positive for ACADS mutations. Twenty-six of 27 patients were positive for c.625G>A variant. Twenty-three of 27 patients harbored susceptibility variants as sole ACADS alterations (18 homozygous and 3 heterozygous for c.625G>A, 2 compound heterozygous for c.625G>A/c.511C>T). Our present fluxomic assessment of SCAD suggests a link between ACADS susceptibility variants and abnormal β-oxidation consistent with known altered kinetics of these variants. Copyright © 2017 Elsevier B.V. All rights reserved.

Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans.

Science.gov (United States)

Tuck, Laura R; Altenbach, Kirsten; Ang, Thiau Fu; Crawshaw, Adam D; Campopiano, Dominic J; Clarke, David J; Marles-Wright, Jon

2016-02-22

The breakdown of fucose and rhamnose released from plant cell walls by the cellulolytic soil bacterium Clostridium phytofermentans produces toxic aldehyde intermediates. To enable growth on these carbon sources, the pathway for the breakdown of fucose and rhamnose is encapsulated within a bacterial microcompartment (BMC). These proteinaceous organelles sequester the toxic aldehyde intermediates and allow the efficient action of acylating aldehyde dehydrogenase enzymes to produce an acyl-CoA that is ultimately used in substrate-level phosphorylation to produce ATP. Here we analyse the kinetics of the aldehyde dehydrogenase enzyme from the fucose/rhamnose utilisation BMC with different short-chain fatty aldehydes and show that it has activity against substrates with up to six carbon atoms, with optimal activity against propionaldehyde. We have also determined the X-ray crystal structure of this enzyme in complex with CoA and show that the adenine nucleotide of this cofactor is bound in a distinct pocket to the same group in NAD(+). This work is the first report of the structure of CoA bound to an aldehyde dehydrogenase enzyme and our crystallographic model provides important insight into the differences within the active site that distinguish the acylating from non-acylating aldehyde dehydrogenase enzymes.

Molecular diagnosis and characterization of medium-chain acyl-CoA dehydrogenase deficiency

DEFF Research Database (Denmark)

Andresen, B S; Bross, P; Jensen, T G

1995-01-01

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common defect in mitochondrial beta-oxidation in humans. It is an autosomal recessive disorder which usually presents in infancy. The disease manifests itself in periods of metabolic stress to the beta-oxidation system and may...... of correct enzyme structure, and does not directly affect the catalytically active regions of the enzyme. We find that our diagnostic set up, consisting of an initial testing by the G985 assay, followed by semi-automated sequencing of DNA from those patients who were indicated to be compound heterozygous...

Production of structured lipids: acyl migration during enzymatic interesterification and downstream processing

DEFF Research Database (Denmark)

Xu, Xuebing

1997-01-01

Production of structured lipids by lipase-catalyzed interesterification attracts great interests recently. Structured lipids are defined, in this article, as triacylglycerols which contain both medium or short chain fatty acids and long chain fatty acids, each groups locating specifically in the sn......-2 position or sn-1,3 positions of glycerol backbone. These kinds of lipids are reported to be promising for both enteral and parenteral nutrition. However, acyl migration occurs in the reaction stage and downstream purification process. This side-reaction causes by-products which are harmful...

Structural characterization of acyl-CoA oxidases reveals a direct link between pheromone biosynthesis and metabolic state in Caenorhabditis elegans.

Science.gov (United States)

Zhang, Xinxing; Li, Kunhua; Jones, Rachel A; Bruner, Steven D; Butcher, Rebecca A

2016-09-06

Caenorhabditis elegans secretes ascarosides as pheromones to communicate with other worms and to coordinate the development and behavior of the population. Peroxisomal β-oxidation cycles shorten the side chains of ascaroside precursors to produce the short-chain ascaroside pheromones. Acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, have different side chain-length specificities and enable C. elegans to regulate the production of specific ascaroside pheromones. Here, we determine the crystal structure of the acyl-CoA oxidase 1 (ACOX-1) homodimer and the ACOX-2 homodimer bound to its substrate. Our results provide a molecular basis for the substrate specificities of the acyl-CoA oxidases and reveal why some of these enzymes have a very broad substrate range, whereas others are quite specific. Our results also enable predictions to be made for the roles of uncharacterized acyl-CoA oxidases in C. elegans and in other nematode species. Remarkably, we show that most of the C. elegans acyl-CoA oxidases that participate in ascaroside biosynthesis contain a conserved ATP-binding pocket that lies at the dimer interface, and we identify key residues in this binding pocket. ATP binding induces a structural change that is associated with tighter binding of the FAD cofactor. Mutations that disrupt ATP binding reduce FAD binding and reduce enzyme activity. Thus, ATP may serve as a regulator of acyl-CoA oxidase activity, thereby directly linking ascaroside biosynthesis to ATP concentration and metabolic state.

Modulation of cellulase activity by charged lipid bilayers with different acyl chain properties for efficient hydrolysis of ionic liquid-pretreated cellulose.

Science.gov (United States)

Mihono, Kai; Ohtsu, Takeshi; Ohtani, Mai; Yoshimoto, Makoto; Kamimura, Akio

2016-10-01

The stability of cellulase activity in the presence of ionic liquids (ILs) is critical for the enzymatic hydrolysis of insoluble cellulose pretreated with ILs. In this work, cellulase was incorporated in the liposomes composed of negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) and zwitterionic phosphatidylcholines (PCs) with different length and degree of unsaturation of the acyl chains. The liposomal cellulase-catalyzed reaction was performed at 45°C in the acetate buffer solution (pH 4.8) with 2.0g/L CC31 as cellulosic substrate. The crystallinity of CC31 was reduced by treating with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) at 120°C for 30min. The liposomal cellulase continuously catalyzed hydrolysis of the pretreated CC31 for 48h producing glucose in the presence of 15wt% [Bmim]Cl. The charged lipid membranes were interactive with [Bmim](+), as elucidated by the [Bmim]Cl-induced alterations in fluorescence polarization of the membrane-embedded 1,6-diphenyl-1,3,5-hexatriene (DPH) molecules. The charged membranes offered the microenvironment where inhibitory effects of [Bmim]Cl on the cellulase activity was relieved. The maximum glucose productivity GP of 10.8 mmol-glucose/(hmol-lipid) was obtained at the reaction time of 48h with the cellulase incorporated in the liposomes ([lipid]=5.0mM) composed of 50mol% POPG and 1,2-dilauroyl-sn-glycero-3-phosohocholine (DLPC) with relatively short and saturated acyl chains. Copyright © 2016 Elsevier B.V. All rights reserved.

Cloning and characterization of human very-long-chain acyl-CoA dehydrogenase cDNA, chromosomal assignment of the gene and identification in four patients of nine different mutations within the VLCAD gene

DEFF Research Database (Denmark)

Andresen, B S; Bross, P; Vianey-Saban, C

1996-01-01

Very-long-chain acyl-CoA dehydrogenase (VLCAD) is one of four straight-chain acyl-CoA dehydrogenase (ACD) enzymes, which are all nuclear encoded mitochondrial flavoproteins catalyzing the initial step in fatty acid beta-oxidation. We have used the very fast, Rapid Amplification of cDNA Ends (RACE...

Acylation of salmon calcitonin modulates in vitro intestinal peptide flux through membrane permeability enhancement

DEFF Research Database (Denmark)

Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon

2015-01-01

hypothesize that tailoring the acylation may be used to optimize intestinal translocation. This work aims to characterize acylated analogues of the therapeutic peptide salmon calcitonin (sCT), which lowers blood calcium, by systematically increasing acyl chain length at two positions, in order to elucidate...... to be optimal, as elongating the chain causes greater binding to the cell membrane but similar permeability, and we speculate that increasing the chain length further may decrease the permeability. In conclusion, acylated sCT acts as its own in vitro intestinal permeation enhancer, with reversible effects...... on Caco-2 cells, indicating that acylation of sCT may represent a promising tool to increase intestinal permeability without adding oral permeation enhancers....

Tandem mass spectrometry screening for very long-chain acyl-CoA dehydrogenase deficiency: the value of second-tier enzyme testing.

Science.gov (United States)

Spiekerkoetter, Ute; Haussmann, Ulrike; Mueller, Martina; ter Veld, Frank; Stehn, Maren; Santer, Rene; Lukacs, Zoltan

2010-10-01

To evaluate newborn screening (NBS) for very long-chain acyl-CoA dehydrogenase deficiency (VLCADD), we further characterized newborns with elevation of one or all C14-carnitine derivatives on NBS from a total of 90 338 newborns. Palmitoyl-CoA oxidation was performed in lymphocytes to define very long-chain acyl-CoA dehydrogenase function. Molecular analysis followed in children with residual activitiesvalues and acylcarnitine ratios did not allow correct identification of the newborn as a patient with VLCADD. Reliable diagnosis is not feasible with acylcarnitine analysis alone. Enzyme analysis in lymphocytes is a reliable and rapid method for correctly assessing all newborns with VLCADD and should be carried out in all newborns identified during the first screening, regardless of the results of a later acylcarnitine profile. Copyright (c) 2010 Mosby, Inc. All rights reserved.

Myopathy in very-long-chain acyl-CoA dehydrogenase deficiency

DEFF Research Database (Denmark)

Scholte, H R; Van Coster, R N; de Jonge, P C

1999-01-01

was deficient in muscle and fibroblasts, consistent with deficiency of very-long-chain acyl-CoA dehydrogenase (VLCAD). The gene of this enzyme had a homozygous deletion of three base pairs in exon 9, skipping lysine residue 238. Fibroblasts oxidised myristate, palmitate and oleate at a rate of 129, 62 and 38......A 30-year-old man suffered since the age of 13 years from exercise induced episodes of intense generalised muscle pain, weakness and myoglobinuria. Fasting ketogenesis was low, while blood glucose remained normal. Muscle mitochondria failed to oxidise palmitoylcarnitine. Palmitoyl-CoA dehydrogenase......% of controls. In contrast to patients with cardiac VLCAD deficiency, our patient had no lipid storage, a normal heart function, a higher rate of oleate oxidation in fibroblasts and normal free carnitine in plasma and fibroblasts. 31P-nuclear magnetic resonance spectroscopy of muscle showed a normal oxidative...

Inhibition of Long Chain Fatty Acyl-CoA Synthetase (ACSL) and Ischemia Reperfusion Injury

Science.gov (United States)

Prior, Allan M.; Zhang, Man; Blakeman, Nina; Datta, Palika; Pham, Hung; Young, Lindon H.; Weis, Margaret T.; Hua, Duy H.

2014-01-01

Various triacsin C analogs, containing different alkenyl chains and carboxylic acid bioisoteres including 4-aminobenzoic acid, isothiazolidine dioxide, hydroxylamine, hydroxytriazene, and oxadiazolidine dione, were synthesized and their inhibitions of long chain fatty acyl-CoA synthetase (ACSL) were examined. Two methods, a cell-based assay of ACSL activity and an in situ [14C]-palmitate incorporation into extractable lipids were used to study the inhibition. Using an in vivo leukocyte recruitment inhibition protocol, the translocation of one or more cell adhesion molecules from the cytoplasm to the plasma membrane on either the endothelium or leukocyte or both was inhibited by inhibitors 1, 9, and triacsin C. The results suggest that inhibition of ACSL may attenuate the vascular inflammatory component associated with ischemia reperfusion injury and lead to a decrease of infarct expansion. PMID:24480468

Structural characterization of acyl-CoA oxidases reveals a direct link between pheromone biosynthesis and metabolic state in Caenorhabditis elegans

Science.gov (United States)

Zhang, Xinxing; Jones, Rachel A.; Bruner, Steven D.; Butcher, Rebecca A.

2016-01-01

Caenorhabditis elegans secretes ascarosides as pheromones to communicate with other worms and to coordinate the development and behavior of the population. Peroxisomal β-oxidation cycles shorten the side chains of ascaroside precursors to produce the short-chain ascaroside pheromones. Acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, have different side chain-length specificities and enable C. elegans to regulate the production of specific ascaroside pheromones. Here, we determine the crystal structure of the acyl-CoA oxidase 1 (ACOX-1) homodimer and the ACOX-2 homodimer bound to its substrate. Our results provide a molecular basis for the substrate specificities of the acyl-CoA oxidases and reveal why some of these enzymes have a very broad substrate range, whereas others are quite specific. Our results also enable predictions to be made for the roles of uncharacterized acyl-CoA oxidases in C. elegans and in other nematode species. Remarkably, we show that most of the C. elegans acyl-CoA oxidases that participate in ascaroside biosynthesis contain a conserved ATP-binding pocket that lies at the dimer interface, and we identify key residues in this binding pocket. ATP binding induces a structural change that is associated with tighter binding of the FAD cofactor. Mutations that disrupt ATP binding reduce FAD binding and reduce enzyme activity. Thus, ATP may serve as a regulator of acyl-CoA oxidase activity, thereby directly linking ascaroside biosynthesis to ATP concentration and metabolic state. PMID:27551084

The frequency of a disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase in sudden infant death syndrome

DEFF Research Database (Denmark)

Banner, Jytte; Gregersen, N; Kølvraa, S

1993-01-01

A number of rare inherited metabolic disorders are known to lead to death in infancy. Deficiency of medium-chain acyl CoA dehydrogenase has, on clinical grounds, been related particularly to sudden infant death syndrome. The contribution of this disorder to the etiology of sudden infant death...... syndrome is still a matter of controversy. The present study investigated 120 well-defined cases of sudden infant death syndrome in order to detect the frequency of the most common disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase (G985) compared with the frequency...... in the general population. A highly specific polymerase chain reaction assay was applied on dried blood spots. No over-representation of homo- or heterozygosity for G985 appears to exist in such a strictly defined population, for which reason it may be more relevant to look at a broader spectrum of clinical...

Thermodynamics of ligand binding to acyl-coenzyme A binding protein studied by titration calorimetry

DEFF Research Database (Denmark)

Færgeman, Nils J.; Sigurskjold, B W; Kragelund, B B

1996-01-01

Ligand binding to recombinant bovine acyl-CoA binding protein (ACBP) was examined using isothermal microcalorimetry. Microcalorimetric measurements confirm that the binding affinity of acyl-CoA esters for ACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-...

Cost-effectiveness analysis of universal newborn screening for medium chain acyl-CoA dehydrogenase deficiency in France

OpenAIRE

Hamers, Françoise F; Rumeau-Pichon, Catherine

2012-01-01

Abstract Background Five diseases are currently screened on dried blood spots in France through the national newborn screening programme. Tandem mass spectrometry (MS/MS) is a technology that is increasingly used to screen newborns for an increasing number of hereditary metabolic diseases. Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is among these diseases. We sought to evaluate the cost-effectiveness of introducing MCADD screening in France. Methods We developed a decision model t...

Remote control of regioselectivity in acyl-acyl carrier protein-desaturases.

Science.gov (United States)

Guy, Jodie E; Whittle, Edward; Moche, Martin; Lengqvist, Johan; Lindqvist, Ylva; Shanklin, John

2011-10-04

Regiospecific desaturation of long-chain saturated fatty acids has been described as approaching the limits of the discriminatory power of enzymes because the substrate entirely lacks distinguishing features close to the site of dehydrogenation. To identify the elusive mechanism underlying regioselectivity, we have determined two crystal structures of the archetypal Δ9 desaturase from castor in complex with acyl carrier protein (ACP), which show the bound ACP ideally situated to position C9 and C10 of the acyl chain adjacent to the diiron active site for Δ9 desaturation. Analysis of the structures and modeling of the complex between the highly homologous ivy Δ4 desaturase and ACP, identified a residue located at the entrance to the binding cavity, Asp280 in the castor desaturase (Lys275 in the ivy desaturase), which is strictly conserved within Δ9 and Δ4 enzymes but differs between them. We hypothesized that interaction between Lys275 and the phosphate of the pantetheine, seen in the ivy model, is key to positioning C4 and C5 adjacent to the diiron center for Δ4 desaturation. Mutating castor Asp280 to Lys resulted in a major shift from Δ9 to Δ4 desaturation. Thus, interaction between desaturase side-chain 280 and phospho-serine 38 of ACP, approximately 27 Å from the site of double-bond formation, predisposes ACP binding that favors either Δ9 or Δ4 desaturation via repulsion (acidic side chain) or attraction (positively charged side chain), respectively. Understanding the mechanism underlying remote control of regioselectivity provides the foundation for reengineering desaturase enzymes to create designer chemical feedstocks that would provide alternatives to those currently obtained from petrochemicals.

A new, simple assay for long-chain acyl-CoA dehydrogenase in cultured skin fibroblasts using stable isotopes and GC-MS

NARCIS (Netherlands)

Niezen-Koning, K. E.; Wanders, R. J.; Nagel, G. T.; IJlst, L.; Heymans, H. S.

1992-01-01

In this paper, we present a new method for measurement of long-chain acyl-CoA dehydrogenase (LCAD) activities in cultured skin fibroblasts. The method is based upon gas chromatographic/mass spectrometric determination of 3-OH-hexadecanoic acid formed during incubation of fibroblasts in a medium

Effect of doxorubicin on the order and dynamics of the acyl chains of anionic and zwitterionic phospholipids in liquid-crystalline mixed model membranes

NARCIS (Netherlands)

Wolf, de F.A.; Nicolaij, K.; Kruijff, de B.

1992-01-01

We investigated the effect of the antineoplastic drug doxorubicin on the order of the acyl chains in liquid-crystalline mixed bilayers consisting of dioleoylphosphatidylserine (DOPS) or -phosphatidic acid (DOPA), and dioleoylphosphatidylcholine (DOPC) or - hosphatidylethanolamine (DOPE). Previous

Metabolism of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine in the human neutrophil

International Nuclear Information System (INIS)

Triggiani, M.; D'Souza, D.M.; Chilton, F.H.

1991-01-01

The biosynthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-2-acetyl-GPC) together with that of 1-alkyl-2-acetyl-GPC (platelet-activating factor) has been demonstrated in a variety of inflammatory cells and tissues. It has been hypothesized that the relative proportion of these phospholipids produced upon cell activation may be influenced by their rates of catabolism. We studied the catabolism of 1-acyl-2-acetyl-GPC in resting and activated human neutrophils and compared it to that of 1-alkyl-2-acetyl-GPC. Neutrophils rapidly catabolize both 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC; however, the rate of catabolism of 1-acyl-2-acetyl-GPC is approximately 2-fold higher than that of 1-alkyl-2-acetyl-GPC. In addition, most of 1-acyl-2-acetyl-GPC is catabolized through a pathway different from that of 1-alkyl-2-acetyl-GPC. The main step in the catabolism of 1-acyl-2-acetyl-GPC is the removal of the long chain at the sn-1 position; the long chain residue is subsequently incorporated either into triglycerides or into phosphatidylcholine. The 1-lyso-2-acetyl-GPC formed in this reaction is then further degraded to glycerophosphocholine, choline, or phosphocholine. 1-Acyl-2-acetyl-GPC is also catabolized, to a lesser extent, through deacetylation at the sn-2 position and reacylation with a long chain fatty acid. Stimulation of neutrophils by A23187 results in a higher rate of catabolism of 1-acyl-2-acetyl-GPC by increasing both the removal of the long chain at the sn-1 position and the deacetylation-reacylation at the sn-2 position. In a broken cell preparation, the cytosolic fraction of the neutrophil was shown to contain an enzyme activity which cleaved the sn-1 position of 1-acyl-2-acetyl-GPC and 1-acyl-2-lyso-GPC but not of 1,2-diacyl-GPC

Acyl-Lipid Metabolism

Science.gov (United States)

Li-Beisson, Yonghua; Shorrosh, Basil; Beisson, Fred; Andersson, Mats X.; Arondel, Vincent; Bates, Philip D.; Baud, Sébastien; Bird, David; DeBono, Allan; Durrett, Timothy P.; Franke, Rochus B.; Graham, Ian A.; Katayama, Kenta; Kelly, Amélie A.; Larson, Tony; Markham, Jonathan E.; Miquel, Martine; Molina, Isabel; Nishida, Ikuo; Rowland, Owen; Samuels, Lacey; Schmid, Katherine M.; Wada, Hajime; Welti, Ruth; Xu, Changcheng; Zallot, Rémi; Ohlrogge, John

2013-01-01

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables. PMID:23505340

Medium-Chain Acyl-CoA Deficiency: Outlines from Newborn Screening, In Silico Predictions, and Molecular Studies

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Serena Catarzi

2013-01-01

Full Text Available Medium-chain acyl-CoA dehydrogenase deficiency (MCADD is a disorder of fatty acid oxidation characterized by hypoglycemic crisis under fasting or during stress conditions, leading to lethargy, seizures, brain damage, or even death. Biochemical acylcarnitines data obtained through newborn screening by liquid chromatography-tandem mass spectrometry (LC-MS/MS were confirmed by molecular analysis of the medium-chain acyl-CoA dehydrogenase (ACADM gene. Out of 324.000 newborns screened, we identified 14 MCADD patients, in whom, by molecular analysis, we found a new nonsense c.823G>T (p.Gly275* and two new missense mutations: c.253G>C (p.Gly85Arg and c.356T>A (p.Val119Asp. Bioinformatics predictions based on both phylogenetic conservation and functional/structural software were used to characterize the new identified variants. Our findings confirm the rising incidence of MCADD whose existence is increasingly recognized due to the efficacy of an expanded newborn screening panel by LC-MS/MS making possible early specific therapies that can prevent possible crises in at-risk infants. We noticed that the “common” p.Lys329Glu mutation only accounted for 32% of the defective alleles, while, in clinically diagnosed patients, this mutation accounted for 90% of defective alleles. Unclassified variants (UVs or VUSs are especially critical when considering screening programs. The functional and pathogenic characterization of genetic variants presented here is required to predict their medical consequences in newborns.

Medium-Chain Acyl-CoA Deficiency: Outlines from Newborn Screening, In Silico Predictions, and Molecular Studies

Science.gov (United States)

Catarzi, Serena; Caciotti, Anna; Thusberg, Janita; Tonin, Rodolfo; Malvagia, Sabrina; la Marca, Giancarlo; Pasquini, Elisabetta; Cavicchi, Catia; Ferri, Lorenzo; Donati, Maria A.; Baronio, Federico; Guerrini, Renzo; Mooney, Sean D.; Morrone, Amelia

2013-01-01

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is a disorder of fatty acid oxidation characterized by hypoglycemic crisis under fasting or during stress conditions, leading to lethargy, seizures, brain damage, or even death. Biochemical acylcarnitines data obtained through newborn screening by liquid chromatography-tandem mass spectrometry (LC-MS/MS) were confirmed by molecular analysis of the medium-chain acyl-CoA dehydrogenase (ACADM) gene. Out of 324.000 newborns screened, we identified 14 MCADD patients, in whom, by molecular analysis, we found a new nonsense c.823G>T (p.Gly275∗) and two new missense mutations: c.253G>C (p.Gly85Arg) and c.356T>A (p.Val119Asp). Bioinformatics predictions based on both phylogenetic conservation and functional/structural software were used to characterize the new identified variants. Our findings confirm the rising incidence of MCADD whose existence is increasingly recognized due to the efficacy of an expanded newborn screening panel by LC-MS/MS making possible early specific therapies that can prevent possible crises in at-risk infants. We noticed that the “common” p.Lys329Glu mutation only accounted for 32% of the defective alleles, while, in clinically diagnosed patients, this mutation accounted for 90% of defective alleles. Unclassified variants (UVs or VUSs) are especially critical when considering screening programs. The functional and pathogenic characterization of genetic variants presented here is required to predict their medical consequences in newborns. PMID:24294134

Defluoridation potential of jute fibers grafted with fatty acyl chain

Science.gov (United States)

Manna, Suvendu; Saha, Prosenjit; Roy, Debasis; Sen, Ramkrishna; Adhikari, Basudam

2015-11-01

Waterborne fluoride is usually removed from water by coagulation, adsorption, ion exchange, electro dialysis or reverse osmosis. These processes are often effective over narrow pH ranges, release ions considered hazardous to human health or produce large volumes of toxic sludge that are difficult to handle and dispose. Although plant matters have been shown to remove waterborne fluoride, they suffer from poor removal efficiency. Following from the insight that interaction between microbial carbohydrate biopolymers and anionic surfaces is often facilitated by lipids, an attempt has been made to enhance fluoride adsorption efficiency of jute by grafting the lignocellulosic fiber with fatty acyl chains found in vegetable oils. Fluoride removal efficiency of grafted jute was found to be comparable or higher than those of alternative defluoridation processes. Infrared and X-ray photoelectron spectroscopic evidence indicated that hydrogen bonding, protonation and C-F bonding were responsible for fluoride accumulation on grafted jute. Adsorption based on grafted jute fibers appears to be an economical, sustainable and eco-friendly alternative technique for removing waterborne fluoride.

Erbium trifluoromethanesulfonate-catalyzed Friedel–Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation

DEFF Research Database (Denmark)

Tran, Phuong Hoang; Hansen, Poul Erik; Nguyen, Hai Truong

2015-01-01

Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel–Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation...... of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste...

Vulnerability to oxidative stress in vitro in pathophysiology of mitochondrial short-chain acyl-CoA dehydrogenase deficiency: response to antioxidants.

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Zarazuela Zolkipli

Full Text Available OBJECTIVE: To elucidate the pathophysiology of SCAD deficient patients who have a unique neurological phenotype, among fatty acid oxidation disorders, with early developmental delay, CNS malformations, intractable seizures, myopathy and clinical signs suggesting oxidative stress. METHODS: We studied skin fibroblast cultures from patients homozygous for ACADS common variant c.625G>A (n = 10, compound heterozygous for c.625G>A/c.319C>T (n = 3 or homozygous for pathogenic c.319C>T (n = 2 and c.1138C>T (n = 2 mutations compared to fibroblasts from patients with carnitine palmitoyltransferase 2 (CPT2 (n = 5, mitochondrial trifunctional protein (MTP/long-chain L-3-hydroxyacyl-CoA dehydrogenase (LCHAD (n = 7, and medium-chain acyl-CoA dehydrogenase (MCAD deficiencies (n = 4 and normal controls (n = 9. All were exposed to 50 µM menadione at 37°C. Additional conditions included exposure to 39°C and/or hypoglycemia. Time to 100% cell death was confirmed with trypan blue dye exclusion. Experiments were repeated with antioxidants (Vitamins C and E or N-acetylcysteine, Bezafibrate or glucose and temperature rescue. RESULTS: The most significant risk factor for vulnerability to menadione-induced oxidative stress was the presence of a FAO defect. SCADD fibroblasts were the most vulnerable compared to other FAO disorders and controls, and were similarly affected, independent of genotype. Cell death was exacerbated by hyperthermia and/or hypoglycemia. Hyperthermia was a more significant independent risk factor than hypoglycemia. Rescue significantly prolonged survival. Incubation with antioxidants and Bezafibrate significantly increased viability of SCADD fibroblasts. INTERPRETATION: Vulnerability to oxidative stress likely contributes to neurotoxicity of SCADD regardless of ACADS genotype and is significantly exacerbated by hyperthermia. We recommend rigorous temperature control in SCADD patients during acute illness

Genetic Basis for Correction of Very‐Long‐Chain Acyl-Coenzyme A Dehydrogenase Deficiency by Bezafibrate in Patient Fibroblasts: Toward a Genotype‐Based Therapy

DEFF Research Database (Denmark)

Gobin‐Limballe, S.; Djouadi, F.; Aubey, F.

2007-01-01

Very‐long‐chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency is an inborn mitochondrial fatty‐acid β‐oxidation (FAO) defect associated with a broad mutational spectrum, with phenotypes ranging from fatal cardiopathy in infancy to adolescent‐onset myopathy, and for which there is no established...

A soluble fatty acyl-acyl carrier protein synthetase from the bioluminescent bacterium Vibrio harveyi.

Science.gov (United States)

Byers, D M; Holmes, C G

1990-01-01

An enzyme catalyzing the ligation of long chain fatty acids to bacterial acyl carrier protein (ACP) has been detected and partially characterized in cell extracts of the bioluminescent bacterium Vibrio harveyi. Acyl-ACP synthetase activity (optimal pH 7.5-8.0) required millimolar concentrations of ATP and Mg2+ and was slightly activated by Ca2+, but was inhibited at high ionic strength and by Triton X-100. ACP from either Escherichia coli (apparent Km = 20 microM) or V. harveyi was used as a substrate. Of the [14C]fatty acids tested as substrates (8-18 carbons), a preference for fatty acids less than or equal to 14 carbons in length was observed. Vibrio harveyi acyl-ACP synthetase appears to be a soluble hydrophilic enzyme on the basis of subcellular fractionation and Triton X-114 phase partition assay. The enzyme was not coinduced with luciferase activity or light emission in vivo during the late exponential growth phase in liquid culture. Acyl-ACP synthetase activity was also detected in extracts from the luminescent bacterium Vibrio fischeri, but not Photobacterium phosphoreum. The cytosolic nature and enzymatic properties of V. harveyi acyl-ACP synthetase indicate that it may have a different physiological role than the membrane-bound activity of E. coli, which has been implicated in phosphatidylethanolamine turnover. Acyl-ACP synthetase activity in V. harveyi could be involved in the intracellular activation and elongation of exogenous fatty acids that occurs in this species or in the reactivation of free myristic acid generated by luciferase.

Short-chain flavor ester synthesis in organic media by an E. coli whole-cell biocatalyst expressing a newly characterized heterologous lipase.

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Guillaume Brault

Full Text Available Short-chain aliphatic esters are small volatile molecules that produce fruity and pleasant aromas and flavors. Most of these esters are artificially produced or extracted from natural sources at high cost. It is, however, possible to 'naturally' produce these molecules using biocatalysts such as lipases and esterases. A gene coding for a newly uncovered lipase was isolated from a previous metagenomic study and cloned into E. coli BL21 (DE3 for overexpression using the pET16b plasmid. Using this recombinant strain as a whole-cell biocatalyst, short chain esters were efficiently synthesized by transesterification and esterification reactions in organic media. The recombinant lipase (LipIAF5-2 showed good affinity toward glyceryl trioctanoate and the highest conversion yields were obtained for the transesterification of glyceryl triacetate with methanol. Using a simple cetyl-trimethylammonium bromide pretreatment increased the synthetic activity by a six-fold factor and the whole-cell biocatalyst showed the highest activity at 40°C with a relatively high water content of 10% (w/w. The whole-cell biocatalyst showed excellent tolerance to alcohol and short-chain fatty acid denaturation. Substrate affinity was equally effective with all primary alcohols tested as acyl acceptors, with a slight preference for methanol. The best transesterification conversion of 50 mmol glyceryl triacetate into isoamyl acetate (banana fragrance provided near 100% yield after 24 hours using 10% biocatalyst loading (w/w in a fluidized bed reactor, allowing recycling of the biocatalyst up to five times. These results show promising potential for an industrial approach aimed at the biosynthesis of short-chain esters, namely for natural flavor and fragrance production in micro-aqueous media.

Acyl-CoA binding proteins; structural and functional conservation over 2000 MYA

DEFF Research Database (Denmark)

Faergeman, Nils J; Wadum, Majken; Feddersen, Søren

2007-01-01

-CoA binding protein, ACBP, has been proposed to play a pivotal role in the intracellular trafficking and utilization of long-chain fatty acyl-CoA esters. Depletion of acyl-CoA binding protein in yeast results in aberrant organelle morphology incl. fragmented vacuoles, multi-layered plasma membranes...... and accumulation of vesicles of variable sizes. In contrast to synthesis and turn-over of glycerolipids, the levels of very-long-chain fatty acids, long-chain bases and ceramide are severely affected by Acb1p depletion, suggesting that Acb1p, rather than playing a general role, serves specific roles in cellular...

Molecular structure, supramolecular organization and thermotropic phase behavior of N-acylglycine alkyl esters with matched acyl and alkyl chains.

Science.gov (United States)

Reddy, S Thirupathi; Swamy, Musti J

2017-11-01

N-Acylglycines (NAGs), the endogenous single-tailed lipids present in rat brain and other mammalian tissues, play significant roles in cell physiology and exhibit interesting pharmacological properties. In the present study, a homologous series of N-acylglycine alkyl esters (NAGEs) with matched chains were synthesized and characterized. Results of differential scanning calorimetric studies revealed that all NAGEs exhibit a single sharp phase transition and that the transition enthalpy and entropy show a linear dependence on the N-acyl and ester alkyl chain length. The structure of N-myristoylglycine myristyl ester (NMGME), solved by single-crystal X-ray diffraction, showed that the molecule adopts a linear geometry and revealed that the structure of N-myristoyl glycyl moiety in NMGME is identical to that in N-myristoylglycine. The molecules are packed in layers with the polar functional groups of the ester and amide functionalities located at the center of the layer. The crystal packing is stabilized by NH⋯O hydrogen bonds between the amide CO and NH groups of adjacent molecules as well as by CH⋯O hydrogen bonds between the amide carbonyl and the methylene CH adjacent to the ester carbonyl of neighboring molecules as well as between ester carbonyl and methylene group of the glycine moiety of adjacent molecules. Powder X-ray diffraction studies showed a linear dependence of the d-spacings on the acyl chain length, suggesting that all NAGEs adopt a structure similar to the packing exhibited in the crystal lattice of NMGME. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantifying Short-Chain Chlorinated Paraffin Congener Groups

NARCIS (Netherlands)

Yuan, Bo; Bogdal, Christian; Berger, Urs; MacLeod, Matthew; Gebbink, Wouter A.; Alsberg, Tomas; Wit, de Cynthia A.

2017-01-01

Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are

Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [11C]-labeled fatty acids

International Nuclear Information System (INIS)

Angsten, Gertrud; Valind, Sven; Takalo, Reijo; Neu, Henrik; Meurling, Staffan; Langstroem, Bengt

2005-01-01

Methods: Anesthetized pigs were studied with [ 11 C]-labeled fatty acids (FAs) with carbon chain length ranging from 8 to 16 carbon atoms, during control conditions and during inhibition of carnitine-palmitoyl transferase I (CPT I) with oxfenicine. The myocardial uptake of [ 11 C]-FAs from blood was measured together with the relative distribution of [ 11 C]-acyl-CoA between rapid mitochondrial oxidation and incorporation into slow turnover lipid pools in the heart. Results: During baseline conditions, the fractional oxidative utilization of palmitate was almost as high as that of carnitine-independent short-chain FAs, unless the carnitine shuttle was inhibited by high levels of lactate. Inhibition of CPT I almost completely blocked the oxidative pathway for palmitic acid and reduced the fractional oxidative utilization, while the rate of oxidative metabolism of acyl-CoA was unaffected. Conclusions: [ 11 C]-Labeled FAs allow rapid oxidation to be well separated from esterification into slow turnover lipid pools in the heart of anaesthetized pigs. The fractional oxidative utilization of [ 11 C]-palmitate serves well to characterize, in vivo, the carnitine-dependent transfer of long-chain FAs

Evidence for involvement of medium chain acyl-CoA dehydrogenase in the metabolism of phenylbutyrate.

Science.gov (United States)

Kormanik, Kaitlyn; Kang, Heejung; Cuebas, Dean; Vockley, Jerry; Mohsen, Al-Walid

2012-12-01

Sodium phenylbutyrate is used for treating urea cycle disorders, providing an alternative for ammonia excretion. Following conversion to its CoA ester, phenylbutyryl-CoA is postulated to undergo one round of β-oxidation to phenylacetyl-CoA, the active metabolite. Molecular modeling suggests that medium chain acyl-CoA dehydrogenase (MCAD; EC 1.3.99.3), a key enzyme in straight chain fatty acid β-oxidation, could utilize phenylbutyryl-CoA as substrate. Moreover, phenylpropionyl-CoA has been shown to be a substrate for MCAD and its intermediates accumulate in patients with MCAD deficiency. We have examined the involvement of MCAD and other acyl-CoA dehydrogenases (ACADs) in the metabolism of phenylbutyryl-CoA. Anaerobic titration of purified recombinant human MCAD with phenylbutyryl-CoA caused changes in the MCAD spectrum that are similar to those induced by octanoyl-CoA, its bona fide substrate, and unique to the development of the charge transfer ternary complex. The calculated apparent dissociation constant (K(D app)) for these substrates was 2.16 μM and 0.12 μM, respectively. The MCAD reductive and oxidative half reactions were monitored using the electron transfer flavoprotein (ETF) fluorescence reduction assay. The catalytic efficiency and the K(m) for phenylbutyryl-CoA were 0.2 mM 34(-1)·sec(-1) and 5.3 μM compared to 4.0 mM(-1)·sec(-1) and 2.8 μM for octanoyl-CoA. Extracts of wild type and MCAD-deficient lymphoblast cells were tested for the ability to reduce ETF using phenylbutyryl-CoA as substrate. While ETF reduction activity was detected in extracts of wild type cells, it was undetectable in extracts of cells deficient in MCAD. The results are consistent with MCAD playing a key role in phenylbutyrate metabolism. Copyright © 2012 Elsevier Inc. All rights reserved.

Thioesterase activity and acyl-CoA/fatty acid cross-talk of hepatocyte nuclear factor-4{alpha}.

Science.gov (United States)

Hertz, Rachel; Kalderon, Bella; Byk, Tamara; Berman, Ina; Za'tara, Ghadeer; Mayer, Raphael; Bar-Tana, Jacob

2005-07-01

Hepatocyte nuclear factor-4alpha (HNF-4alpha) activity is modulated by natural and xenobiotic fatty acid and fatty acyl-CoA ligands as a function of their chain length, unsaturation, and substitutions. The acyl-CoA site of HNF-4alpha is reported here to consist of the E-F domain, to bind long-chain acyl-CoAs but not the respective free acids, and to catalyze the hydrolysis of bound fatty acyl-CoAs. The free acid pocket, previously reported in the x-ray structure of HNF-4alpha E-domain, entraps fatty acids but excludes acyl-CoAs. The acyl-CoA and free acid sites are distinctive and noncongruent. Free fatty acid products of HNF-4alpha thioesterase may exchange with free acids entrapped in the fatty acid pocket of HNF-4alpha. Cross-talk between the acyl-CoA and free fatty acid binding sites is abrogated by high affinity, nonhydrolyzable acyl-CoA ligands of HNF-4alpha that inhibit its thioesterase activity. Hence, HNF-4alpha transcriptional activity is controlled by its two interrelated acyl ligands and two binding sites interphased in tandem by the thioesterase activity. The acyl-CoA/free-acid and receptor/enzyme duality of HNF-4alpha extends the paradigm of nuclear receptors.

Effects of two mutations detected in medium chain acyl-CoA dehydrogenase (MCAD)-deficient patients on folding, oligomer assembly, and stability of MCAD enzyme

DEFF Research Database (Denmark)

Bross, P; Jespersen, C; Jensen, T G

1995-01-01

We have used expression of human medium chain acyl-CoA dehydrogenase (MCAD) in Escherichia coli as a model system for dissecting the molecular effects of two mutations detected in patients with MCAD deficiency. We demonstrate that the R28C mutation predominantly affects polypeptide folding...

Photoaffinity Labeling of Developing Jojoba Seed Microsomal Membranes with a Photoreactive Analog of Acyl-Coenzyme A (Acyl-CoA) (Identification of a Putative Acyl-CoA:Fatty Alcohol Acyltransferase.

Science.gov (United States)

Shockey, J. M.; Rajasekharan, R.; Kemp, J. D.

1995-01-01

Jojoba (Simmondsia chinensis, Link) is the only plant known that synthesizes liquid wax. The final step in liquid wax biosynthesis is catalyzed by an integral membrane enzyme, fatty acyl-coenzyme A (CoA):fatty alcohol acyltransferase, which transfers an acyl chain from acyl-CoA to a fatty alcohol to form the wax ester. To purify the acyltransferase, we have labeled the enzyme with a radioiodinated, photoreactive analog of acyl-CoA, 12-[N-(4-azidosalicyl)amino] dodecanoyl-CoA (ASD-CoA). This molecule acts as an inhibitor of acyltransferase activity in the dark and as an irreversible inhibitor upon exposure to ultraviolet light. Oleoyl-CoA protects enzymatic activity in a concentration-dependent manner. Photolysis of microsomal membranes with labeled ASD-CoA resulted in strong labeling of two polypeptides of 57 and 52 kD. Increasing concentrations of oleoyl-CoA reduced the labeling of the 57-kD polypeptide dramatically, whereas the labeling of the 52-kD polypeptide was much less responsive to oleoyl-CoA. Also, unlike the other polypeptide, the labeling of the 57-kD polypeptide was enhanced considerably when photolyzed in the presence of dodecanol. These results suggest that a 57-kD polypeptide from jojoba microsomes may be the acyl-CoA:fatty alcohol acyltransferase.

Enzymatic hydrolysis of short-chain lecithin/long-chain phospholipid unilamellar vesicles: sensitivity of phospholipases to matrix phase state.

Science.gov (United States)

Gabriel, N E; Agman, N V; Roberts, M F

1987-11-17

Short-chain lecithin/long-chain phospholipid unilamellar vesicles (SLUVs), unlike pure long-chain lecithin vesicles, are excellent substrates for water-soluble phospholipases. Hemolysis assays show that greater than 99.5% of the short-chain lecithin is partitioned in the bilayer. In these binary component vesicles, the short-chain species is the preferred substrate, while the long-chain phospholipid can be treated as an inhibitor (phospholipase C) or poor substrate (phospholipase A2). For phospholipase C Bacillus cereus, apparent Km and Vmax values show that bilayer-solubilized diheptanoylphosphatidylcholine (diheptanoyl-PC) is nearly as good a substrate as pure micellar diheptanoyl-PC, although the extent of short-chain lecithin hydrolysis depends on the phase state of the long-chain lipid. For phospholipase A2 Naja naja naja, both Km and Vmax values show a greater range: in a gel-state matrix, diheptanoyl-PC is hydrolyzed with micellelike kinetic parameters; in a liquid-crystalline matrix, the short-chain lecithin becomes comparable to the long-chain component. Both enzymes also show an anomalous increase in specific activity toward diheptanoyl-PC around the phase transition temperature of the long-chain phospholipid. Since the short-chain lecithin does not exhibit a phase transition, this must reflect fluctuations in head-group area or vertical motions of the short-chain lecithin caused by surrounding long-chain lecithin molecules. These results are discussed in terms of a specific model for SLUV hydrolysis and a general explanation for the "interfacial activation" observed with water-soluble phospholipases.

Inhibition of carnitine-acyl transferase I by oxfenicine studied in vivo with [{sup 11}C]-labeled fatty acids

Energy Technology Data Exchange (ETDEWEB)

Angsten, Gertrud [Department of Pediatric Surgery, University Children' s Hospital, S-751 85 Uppsala (Sweden)]. E-mail: gertrud.angsten@surgsci.uu.se; Valind, Sven [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Clinical Physiology, University Hospital, S-751 85 Uppsala (Sweden); Takalo, Reijo [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Clinical Physiology, University Hospital, S-751 85 Uppsala (Sweden); Neu, Henrik [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Organic Chemistry, Uppsala University, S-751 24 Uppsala (Sweden); Meurling, Staffan [Department of Pediatric Surgery, University Children' s Hospital, S-751 85 Uppsala (Sweden); Langstroem, Bengt [Uppsala University PET Centre, Uppsala University, S-751 05 Uppsala (Sweden); Department of Organic Chemistry, Uppsala University, S-751 24 Uppsala (Sweden)

2005-07-01

Methods: Anesthetized pigs were studied with [{sup 11}C]-labeled fatty acids (FAs) with carbon chain length ranging from 8 to 16 carbon atoms, during control conditions and during inhibition of carnitine-palmitoyl transferase I (CPT I) with oxfenicine. The myocardial uptake of [{sup 11}C]-FAs from blood was measured together with the relative distribution of [{sup 11}C]-acyl-CoA between rapid mitochondrial oxidation and incorporation into slow turnover lipid pools in the heart. Results: During baseline conditions, the fractional oxidative utilization of palmitate was almost as high as that of carnitine-independent short-chain FAs, unless the carnitine shuttle was inhibited by high levels of lactate. Inhibition of CPT I almost completely blocked the oxidative pathway for palmitic acid and reduced the fractional oxidative utilization, while the rate of oxidative metabolism of acyl-CoA was unaffected. Conclusions: [{sup 11}C]-Labeled FAs allow rapid oxidation to be well separated from esterification into slow turnover lipid pools in the heart of anaesthetized pigs. The fractional oxidative utilization of [{sup 11}C]-palmitate serves well to characterize, in vivo, the carnitine-dependent transfer of long-chain FAs.

Role of acylCoA binding protein in acylCoA transport, metabolism and cell signaling

DEFF Research Database (Denmark)

Knudsen, J; Jensen, M V; Hansen, J K

1999-01-01

and pool formation and therefore also for the function of LCAs as metabolites and regulators of cellular functions [1]. The major factors controlling the free concentration of cytosol long chain acylCoA ester (LCA) include ACBP [2], sterol carrier protein 2 (SCP2) [3] and fatty acid binding protein (FABP...

Identification of N-acyl-fumonisin B1 as new cytotoxic metabolites of fumonisin mycotoxins.

Science.gov (United States)

Harrer, Henning; Laviad, Elad L; Humpf, Hans Ulrich; Futerman, Anthony H

2013-03-01

Fumonisins are mycotoxins produced by Fusarium species. The predominant derivative, fumonisin B1 (FB1), occurs in food and feed and is of health concern due to its hepatotoxic and carcinogenic effects. However, the role of FB1 metabolites on the mechanism of the toxicity, the inhibition of the ceramide synthesis, is unknown. The aim of this study was to identify new fumonisin metabolites and to evaluate their cytotoxic potential. MS, molecular biology, and in vitro enzyme assays were used to investigate fumonisin metabolism in mammalian cells overexpressing human ceramide synthase (CerS) genes. N-acyl-FB1 derivatives were detected as new metabolites in cultured cells at levels of up to 10 pmol/mg of protein. The N-acylation of FB1 and hydrolyzed FB1 was analyzed in several cell lines, including cells overexpressing CerS. The acyl-chain length of the N-acyl fumonisins depends on the CerS isoform acylating them. The N-acyl fumonisins are more cytotoxic than the parent fumonisin B1. The identification of N-acyl fumonisins with various acyl chain lengths together with the observed cytotoxicity of these compounds is a new aspect of fumonisin-related toxicity. Therefore, these new metabolites might play an important role in the mode of action of fumonisins. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, characterisation and physicochemical properties of hydrophobically modified inulin using long-chain fatty acyl chlorides.

Science.gov (United States)

Han, Lingyu; Ratcliffe, I; Williams, P A

2017-12-15

A series of inulin derivatives were synthesized in aqueous solution using acyl chlorides with varying alkyl chain length (C10-C16). They were characterised using a number of techniques including MALDI TOF-MS, 1 H NMR and FTIR and their degree of substitution determined. The solution properties of the hydrophobically modified inulins were investigated using dye solubilisation and surface tension and it was confirmed that the molecules aggregated in solution above a critical concentration (critical aggregation concentration, CAC). The value of the CAC was found to be reasonably consistent between the different techniques and was shown to decrease with increasing hydrophobe chain length. It was found that the C10, C12 and C14 derivatives formed stable oil-in-water emulsions and the emulsion droplet size decreased with increasing alkyl chain length. The C16 derivative was not able to produce stable oil-in-water emulsions; however, it was able to form stable water-in-oil emulsions. The fact that the derivatives are able to form micellar-like aggregates and stabilise emulsions makes them suitable candidates for the encapsulation and delivery of active compounds with potential application in food, cosmetic, personal care and pharmaceutical formulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

N-acyl phosphatidylethanolamines affect the lateral distribution of cholesterol in membranes

DEFF Research Database (Denmark)

Térová, B.; Slotte, J.P.; Petersen, G.

2005-01-01

-acyl-POPE) or N-acyl-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (N-acyl-DPPE), and how the molecules interacted with cholesterol. The gel ¿ liquid crystalline transition temperature of sonicated N-acyl phosphatidylethanolamine vesicles in water correlated positively with the number of palmitic acyl chains...... in the molecules. Based on diphenylhexatriene steady state anisotropy measurements, the presence of 33 mol% cholesterol in the membranes removed the phase transition from N-oleoyl-POPE bilayers, but failed to completely remove it from N-palmitoyl-DPPE and N-palmitoyl-POPE bilayers, suggesting rather weak...... interaction of cholesterol with the N-saturated NAPEs. The rate of cholesterol desorption from mixed monolayers containing N-palmitoyl-DPPE and cholesterol (1:1 molar ratio) was much higher compared to cholesterol/DPPE binary monolayers, suggesting a weak cholesterol interaction with N-palmitoyl-DPPE also...

Activation of Exogenous Fatty Acids to Acyl-Acyl Carrier Protein Cannot Bypass FabI Inhibition in Neisseria*

Science.gov (United States)

Yao, Jiangwei; Bruhn, David F.; Frank, Matthew W.; Lee, Richard E.; Rock, Charles O.

2016-01-01

Neisseria is a Gram-negative pathogen with phospholipids composed of straight chain saturated and monounsaturated fatty acids, the ability to incorporate exogenous fatty acids, and lipopolysaccharides that are not essential. The FabI inhibitor, AFN-1252, was deployed as a chemical biology tool to determine whether Neisseria can bypass the inhibition of fatty acid synthesis by incorporating exogenous fatty acids. Neisseria encodes a functional FabI that was potently inhibited by AFN-1252. AFN-1252 caused a dose-dependent inhibition of fatty acid synthesis in growing Neisseria, a delayed inhibition of growth phenotype, and minimal inhibition of DNA, RNA, and protein synthesis, showing that its mode of action is through inhibiting fatty acid synthesis. Isotopic fatty acid labeling experiments showed that Neisseria encodes the ability to incorporate exogenous fatty acids into its phospholipids by an acyl-acyl carrier protein-dependent pathway. However, AFN-1252 remained an effective antibacterial when Neisseria were supplemented with exogenous fatty acids. These results demonstrate that extracellular fatty acids are activated by an acyl-acyl carrier protein synthetase (AasN) and validate type II fatty acid synthesis (FabI) as a therapeutic target against Neisseria. PMID:26567338

Developing Exchange in Short Local Foods Supply Chains

Directory of Open Access Journals (Sweden)

Per Engelseth

2016-07-01

Full Text Available The supply chain management of foods is commonly associated with modernistic large-scale production. This involves long transport distances of foods to reach consumers. In the case of local foods, supply chains are shorter. Based on a case study of five local foods producer's supply of their products to a common retailer, the supply chain of local foods is modelled conceptually and modes of development are pointed out based on contingency theory and supply chain management literature. Findings reveal that since these chains are transparent, reciprocal interdependency is abundant mainly because human perception creates a sufficient understanding of the operations management issues pertinent within this simple inter-organisational structure. Local foods supply chains are similar to service supply chains. This includes that both are short in nature and associated with bi-directional interaction between the customer and supplier. Developing short supply chains in local foods supply is associated with improving the exchange economy found in short supply chains. This also implies that development of local foods supply is associated with two paths which may be complementary. First, the use of improved intensive technology associated with reciprocal interdependency to develop efficiencies in the bi-directional and somewhat complex interaction. Alternatively local foods suppliers may seek to reduce this form of reciprocal interdependency thereby increasing the impact of pooled interdependencies and enabling using mediating technology involving standardising interaction such as through increased standardised products and packaging as well as automation of information connectivity.

Effect of room temperature ionic liquid structure on the enzymatic acylation of flavonoids

DEFF Research Database (Denmark)

Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

2010-01-01

Enzymatic acylation reactions of flavonoids (rutin, esculin) with long chain fatty acids (palmitic, oleic acids) were carried out in 14 different ionic liquid media containing a range of cation and anion structures. Classification of RTILs according to flavonoid solubility (using COSMO...... must be struck that maximized flavonoid solubility with minimum negative impact on lipase activity. The process also benefitted from an increased reaction temperature which may have helped to reduced mass transfer limitations. Keywords: Room temperature ionic liquids (RTILs); Biosynthesis; Acylation......; Flavonoids; Lipase; Long chain fatty acids...

OleA Glu117 is key to condensation of two fatty-acyl coenzyme A substrates in long-chain olefin biosynthesis

Energy Technology Data Exchange (ETDEWEB)

Jensen, Matthew R.; Goblirsch, Brandon R.; Christenson, James K.; Esler, Morgan A.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M. (UMM)

2017-10-12

In the interest of decreasing dependence on fossil fuels, microbial hydrocarbon biosynthesis pathways are being studied for renewable, tailored production of specialty chemicals and biofuels. One candidate is long-chain olefin biosynthesis, a widespread bacterial pathway that produces waxy hydrocarbons. Found in three- and four-gene clusters, oleABCD encodes the enzymes necessary to produce cis-olefins that differ by alkyl chain length, degree of unsaturation, and alkyl chain branching. The first enzyme in the pathway, OleA, catalyzes the Claisen condensation of two fatty acyl-coenzyme A (CoA) molecules to form a β-keto acid. In this report, the mechanistic role of Xanthomonas campestris OleA Glu117 is investigated through mutant enzymes. Crystal structures were determined for each mutant as well as their complex with the inhibitor cerulenin. Complemented by substrate modeling, these structures suggest that Glu117 aids in substrate positioning for productive carbon–carbon bond formation. Analysis of acyl-CoA substrate hydrolysis shows diminished activity in all mutants. When the active site lacks an acidic residue in the 117 position, OleA cannot form condensed product, demonstrating that Glu117 has a critical role upstream of the essential condensation reaction. Profiling of pH dependence shows that the apparent pKa for Glu117 is affected by mutagenesis. Taken together, we propose that Glu117 is the general base needed to prime condensation via deprotonation of the second, non-covalently bound substrate during turnover. This is the first example of a member of the thiolase superfamily of condensing enzymes to contain an active site base originating from the second monomer of the dimer.

Physical Characteristics of Tetrahydroxy and Acylated Derivatives of Jojoba Liquid Wax in Lubricant Applications.

Science.gov (United States)

Harry-O'kuru, Rogers E; Biresaw, Girma; Gordon, Sherald; Xu, Jingyuan

2018-01-01

Jojoba liquid wax is a mixture of esters of long-chain fatty acids and fatty alcohols mainly C38:2-C46:2. The oil exhibits excellent emolliency on the skin and, therefore, is a component in many personal care cosmetic formulations. The virgin oil is a component of the seed of the jojoba ( Simmondsia chinensis ) plant which occurs naturally in the Sonora Desert in the United States and northwestern Mexico as well as in the northeastern Sahara desert. The seed contains 50-60% oil by dry weight. The plant has been introduced into Australia, Argentina, and Israel for commercial production of the jojoba oil. As a natural lubricant, we are seeking to explore its potential as a renewable industrial lubricant additive. Thus, we have chemically modified the carbon-carbon double bonds in the oil structure in order to improve its already good resistance to air oxidation so as to enhance its utility as well as its shelf life in nonpersonal care applications. To achieve this goal, we have hydroxylated its -C=C- bonds. Acylation of the resulting hydroxyl moieties has generated short-chain vicinal acyl substituents on the oil which keep the wax liquid, improving its cold flow properties and also protecting it from auto-oxidation and rancidity.

Physical Characteristics of Tetrahydroxy and Acylated Derivatives of Jojoba Liquid Wax in Lubricant Applications

Directory of Open Access Journals (Sweden)

Rogers E. Harry-O’kuru

2018-01-01

Full Text Available Jojoba liquid wax is a mixture of esters of long-chain fatty acids and fatty alcohols mainly C38:2–C46:2. The oil exhibits excellent emolliency on the skin and, therefore, is a component in many personal care cosmetic formulations. The virgin oil is a component of the seed of the jojoba (Simmondsia chinensis plant which occurs naturally in the Sonora Desert in the United States and northwestern Mexico as well as in the northeastern Sahara desert. The seed contains 50–60% oil by dry weight. The plant has been introduced into Australia, Argentina, and Israel for commercial production of the jojoba oil. As a natural lubricant, we are seeking to explore its potential as a renewable industrial lubricant additive. Thus, we have chemically modified the carbon-carbon double bonds in the oil structure in order to improve its already good resistance to air oxidation so as to enhance its utility as well as its shelf life in nonpersonal care applications. To achieve this goal, we have hydroxylated its –C=C– bonds. Acylation of the resulting hydroxyl moieties has generated short-chain vicinal acyl substituents on the oil which keep the wax liquid, improving its cold flow properties and also protecting it from auto-oxidation and rancidity.

Medium-chain acyl-CoA dehydrogenase (MCAD) mutations identified by MS/MS-based prospective screening of newborns differ from those observed in patients with clinical symptoms

DEFF Research Database (Denmark)

Andresen, B S; Dobrowolski, S F; O'Reilly, L

2001-01-01

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most frequently diagnosed mitochondrial beta-oxidation defect, and it is potentially fatal. Eighty percent of patients are homozygous for a common mutation, 985A-->G, and a further 18% have this mutation in only one disease allele. In a...

On the Unusual Homeoviscous Adaptation of the Membrane Fatty Acyl Components against the Thermal Stress in RhiΖobium meliloti

International Nuclear Information System (INIS)

Kang, Seb Yung; Jung, Seun Ho; Choi, Yong Hoon; Yang, Chul Hak; Kim, Hyun Won

1999-01-01

In order to maintain the optimal fluidity in membrane, microorganism genetically regulates the ratio of the unsaturated fatty acids (Ufos) to saturated ones of its biological membrane in response to external perturbing condition such as the change of temperature. The remodelling of fatty acyl chain composition is the most frequently observed response to altered growth temperature. It is reflected in the elevated proportions of unsaturated fatty acid (UFAs) at low temperature. Because cis double bonds, normally positioned at the middle of fatty acyl chains, introduce a kink of approximately 30 .deg. into acyl chain, UFAs pack less compactly and exhibit lower melting points than their saturated homologues. Thus, enrichment of membranes with UFAs offsets, to a significant degree, the increase in membrane order caused by a drop in temperature. This is so called homeoviscous adaptation of the membrane fatty acyl chains against thermal stress. Membrane maintains the optimal viscosity using homeoviscous adaptation.

The membrane interaction of amphiphilic model peptides affects phosphatidylserine headgroup and acyl chain order and dynamics. Application of the phospholipid headgroup electrometer concept to phosphatidylserine

International Nuclear Information System (INIS)

de Kroon, A.I.P.M.; Killian, J.A.; de Gier, J.; de Kruijff, B.

1991-01-01

Deuterium nuclear magnetic resonance ( 2 H NMR) was used to study the interaction of amphiphilic model peptides with model membranes consisting of 1,2-dioleoyl-sn-glycero-3-phospho-L-serine deuterated either at the β-position of the serine moiety ([2- 2 H]DOPS) or at the 11-position of the acyl chains ([11,11- 2 H 2 ]DOPS). The peptides are derived from the sequences H-Ala-Met-Leu-Trp-Ala-OH and H-Arg-Met-Leu-Trp-Ala-OH and contain a positive charge of +1 or +2 at the amino terminus or one positive charge at each end of the molecule. Upon titration of dispersions of DOPS with the peptides, the divalent peptides show a similar extent of binding to the DOPS bilyers, which is larger than that of the single charged peptide. Under these conditions the values of the quadrupolar splitting of both [2- 2 H]DOPS and [11,11- 2 H 2 ]DOPS are decreased, indicating that the peptides reduce the order of both the DOPS headgroup and the acyl chains. The extent of the decrease depends on the amount of peptide bound and on the position of the charged moieties in the peptide molecule. Titrations of DOPS with poly(L-lysine) 100 , which were included for reasons of comparison, reveal increased Δv q values. When the peptide-lipid titrations are carried out without applying a freeze-thaw procedure to achieve full equilibration, two-component 2 H NMR spectra occur. The apparently limited accessibility of the lipid to the peptides under these circumstances is discussed in relation to the ability of the peptides to exhibit transbilayer movement. 2 H spin-lattice relaxation time T1 measurements demonstrate a decrease of the rates of motion of both headgroup and acyl chains of DOPS in the presence of the peptides

Metabolic alkene labeling and in vitro detection of histone acylation via the aqueous oxidative Heck reaction

NARCIS (Netherlands)

Ourailidou, Maria E; Dockerty, Paul; Witte, Martin; Poelarends, Gerrit J; Dekker, Frank J

2015-01-01

The detection of protein lysine acylations remains a challenge due to lack of specific antibodies for acylations with various chain lengths. This problem can be addressed by metabolic labeling techniques using carboxylates with reactive functionalities. Subsequent chemoselective reactions with a

Capillary condensation of short-chain molecules.

Science.gov (United States)

Bryk, Paweł; Pizio, Orest; Sokolowski, Stefan

2005-05-15

A density-functional study of capillary condensation of fluids of short-chain molecules confined to slitlike pores is presented. The molecules are modeled as freely jointed tangent spherical segments with a hard core and with short-range attractive interaction between all the segments. We investigate how the critical parameters of capillary condensation of the fluid change when the pore width decreases and eventually becomes smaller than the nominal linear dimension of the single-chain molecule. We find that the dependence of critical parameters for a fluid of dimers and of tetramers on pore width is similar to that of the monomer fluid. On the other hand, for a fluid of chains consisting of a larger number of segments we observe an inversion effect. Namely, the critical temperature of capillary condensation decreases with increasing pore width for a certain interval of values of the pore width. This anomalous behavior is also influenced by the interaction between molecules and pore walls. We attribute this behavior to the effect of conformational changes of molecules upon confinement.

Ultrasonic pretreatment for lipase-catalyed synthesis of phytosterol esters with different acyl donors.

Science.gov (United States)

Zheng, Ming-Ming; Wang, Lian; Huang, Feng-Hong; Dong, Ling; Guo, Ping-Mei; Deng, Qian-Chun; Li, Wen-Lin; Zheng, Chang

2012-09-01

This study is focused on the enzymatic esterification of phytosterols with different acyl donors to produce the corresponding phytosterol esters catalyzed by Canadia sp. 99-125 lipase under ultrasound irradiation. An ultrasonic frequency of 35 kHz, power of 200 W and time of 1h was determined to guarantee satisfactory degree of esterification and lipase activity. The influence of temperature, substrates concentration and molar ratio was investigated subsequently. The optimum production was achieved in isooctane system at 60°C with phytosterol concentration of 150 μmol/mL and phytosterol to fatty acid molar ratio of 1:1.5, resulting in a phytosterol esters conversion of above 85.7% in short reaction time (8h). Phytosterols esters could also be converted in high yields to the corresponding long-chain acyl esters via transesterification with triacylglycerols (above 90.3%) under ultrasound irradiation. In optimum conditions, the overall esterification reaction rate using the ultrasonic pretreatment process was above 2-fold than that of mechanical stirring process without damage the lipase activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Stearoyl-acyl carrier protein and unusual acyl-acyl carrier protein desaturase activities are differentially influenced by ferredoxin.

Science.gov (United States)

Schultz, D J; Suh, M C; Ohlrogge, J B

2000-10-01

Acyl-acyl carrier protein (ACP) desaturases function to position a single double bond into an acyl-ACP substrate and are best represented by the ubiquitous Delta9 18:0-ACP desaturase. Several variant acyl-ACP desaturases have also been identified from species that produce unusual monoenoic fatty acids. All known acyl-ACP desaturase enzymes use ferredoxin as the electron-donating cofactor, and in almost all previous studies the photosynthetic form of ferredoxin rather than the non-photosynthetic form has been used to assess activity. We have examined the influence of different forms of ferredoxin on acyl-ACP desaturases. Using combinations of in vitro acyl-ACP desaturase assays and [(14)C]malonyl-coenzyme A labeling studies, we have determined that heterotrophic ferredoxin isoforms support up to 20-fold higher unusual acyl-ACP desaturase activity in coriander (Coriandrum sativum), Thunbergia alata, and garden geranium (Pelargonium x hortorum) when compared with photosynthetic ferredoxin isoforms. Heterotrophic ferredoxin also increases activity of the ubiquitous Delta9 18:0-ACP desaturase 1.5- to 3.0-fold in both seed and leaf extracts. These results suggest that ferredoxin isoforms may specifically interact with acyl-ACP desaturases to achieve optimal enzyme activity and that heterotrophic isoforms of ferredoxin may be the in vivo electron donor for this reaction.

Parental Experiences of Raising a Child With Medium Chain Acyl-CoA Dehydrogenase Deficiency

Directory of Open Access Journals (Sweden)

Hilary Piercy

2017-05-01

Full Text Available Newborn screening enabling early diagnosis of medium chain acyl-CoA dehydrogenase deficiency (MCADD has dramatically improved health outcomes in children with MCADD. Achieving those outcomes depends on effective management by parents. Understanding parental management strategies and associated anxieties and concerns is needed to inform provision of appropriate care and support. Semistructured interviews were conducted with a purposive sample of parents of children aged 2 to 12 years. Thematic analysis identified two main themes. Managing dietary intake examined how parents managed day-to-day dietary intake to ensure adequate intake and protection of safe fasting intervals. Managing and preventing illness events explored parental experiences of managing illness events and their approach to preventing these events. Management strategies were characterized by caution and vigilance and influenced by a lack of confidence in others to manage the condition. The study identifies the need for increased awareness of the condition, particularly in relation to emergency treatment.

Mixed-chain phosphatidylcholine bilayers: structure and properties

International Nuclear Information System (INIS)

Mattai, J.; Sripada, P.K.; Shipley, G.G.

1987-01-01

Calorimetric and x-ray diffraction data are reported for two series of saturated mixed-chain phosphatidylcholines (PCs), 18:0/n:0-PC and n:0/18:0-PC, where the sn-1 and sn-2 fatty acyl chains on the glycerol backbone are systematically varied by two methylene groups from 18:0 to 10:0 (n = 18, 16, 14, 12, or 10). Fully hydrated PCs were annealed at -4 0 C and their multilamellar dispersions characterized by differential scanning calorimetry and x-ray diffraction. All mixed-chain PCs form low-temperature crystalline bilayer phases following low-temperature incubation, except 18:0/10:0-PC. The subtransition temperature (T/sub s/) shifts toward the main (chain melting) transition temperature (T/sub m/) as the sn-1 or sn-2 fatty acyl chain is reduced in length. T/sub m/ decreases with acyl chain length for both series of PCs except 18:0/10:0-PC, while for the positional isomers, n:0/18:0-PC and 18:0/n:0-PC, T/sub m/ is higher for the isomer with the longer acyl chain in the sn-2 position of the glycerol backbone. The conversion from the crystalline bilayer L/sub c/phase to the liquid-crystalline L/sub α/ phase with melted hydrocarbon chains occurs through a series of phase changes which are chain length dependent. Molecular models indicate that the bilayer gel phases for the more asymmetric PC series, 18:0/n:0-PC, must undergo progressive interdigitation with chain length reduction to maintain maximum chain-chain interaction. The L/sub β/* phase of 18:0/10:p-PC is the most stable structure for this PC below T/sub m/. The formation and stability of the triple-chain structures can be rationalized from molecular models

Plant fatty acyl reductases: enzymes generating fatty alcohols for protective layers with potential for industrial applications.

Science.gov (United States)

Rowland, Owen; Domergue, Frédéric

2012-09-01

Primary fatty alcohols are found throughout the biological world, either in free form or in a combined state. They are common components of plant surface lipids (i.e. cutin, suberin, sporopollenin, and associated waxes) and their absence can significantly perturb these essential barriers. Fatty alcohols and/or derived compounds are also likely to have direct functions in plant biotic and abiotic interactions. An evolutionarily related set of alcohol-forming fatty acyl reductases (FARs) is present in all kingdoms of life. Plant microsomal and plastid-associated FAR enzymes have been characterized, acting on acyl-coenzymeA (acyl-CoA) or acyl-acyl carrier protein (acyl-ACP) substrates, respectively. FARs have distinct substrate specificities both with regard to chain length and chain saturation. Fatty alcohols and wax esters, which are a combination of fatty alcohol and fatty acid, have a variety of commercial applications. The expression of FARs with desired specificities in transgenic microbes or oilseed crops would provide a novel means of obtaining these valuable compounds. In the present review, we report on recent progress in characterizing plant FAR enzymes and in understanding the biological roles of primary fatty alcohols, as well as describe the biotechnological production and industrial uses of fatty alcohols. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stearoyl-Acyl Carrier Protein and Unusual Acyl-Acyl Carrier Protein Desaturase Activities Are Differentially Influenced by Ferredoxin1

Science.gov (United States)

Schultz, David J.; Suh, Mi Chung; Ohlrogge, John B.

2000-01-01

Acyl-acyl carrier protein (ACP) desaturases function to position a single double bond into an acyl-ACP substrate and are best represented by the ubiquitous Δ9 18:0-ACP desaturase. Several variant acyl-ACP desaturases have also been identified from species that produce unusual monoenoic fatty acids. All known acyl-ACP desaturase enzymes use ferredoxin as the electron-donating cofactor, and in almost all previous studies the photosynthetic form of ferredoxin rather than the non-photosynthetic form has been used to assess activity. We have examined the influence of different forms of ferredoxin on acyl-ACP desaturases. Using combinations of in vitro acyl-ACP desaturase assays and [14C]malonyl-coenzyme A labeling studies, we have determined that heterotrophic ferredoxin isoforms support up to 20-fold higher unusual acyl-ACP desaturase activity in coriander (Coriandrum sativum), Thunbergia alata, and garden geranium (Pelargonium × hortorum) when compared with photosynthetic ferredoxin isoforms. Heterotrophic ferredoxin also increases activity of the ubiquitous Δ9 18:0-ACP desaturase 1.5- to 3.0-fold in both seed and leaf extracts. These results suggest that ferredoxin isoforms may specifically interact with acyl-ACP desaturases to achieve optimal enzyme activity and that heterotrophic isoforms of ferredoxin may be the in vivo electron donor for this reaction. PMID:11027717

Identification of unusual phospholipid fatty acyl compositions of Acanthamoeba castellanii.

Directory of Open Access Journals (Sweden)

Marta Palusinska-Szysz

Full Text Available Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL. The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e.g. bacteria and develop more efficient treatment strategies. Therefore, the detailed PL composition of Acanthamoeba castellanii was investigated by 31P nuclear magnetic resonance spectroscopy, thin-layer chromatography, gas chromatography, high performance liquid chromatography and liquid chromatography-mass spectrometry. Normal and reversed phase liquid chromatography coupled with mass spectrometric detection was used for detailed characterization of the fatty acyl composition of each detected PL. The most abundant fatty acyl residues in each PL class were octadecanoyl (18∶0, octadecenoyl (18∶1 Δ9 and hexadecanoyl (16∶0. However, some selected PLs contained also very long fatty acyl chains: the presence of 28- and 30-carbon fatty acyl residues was confirmed in phosphatidylethanolamine (PE, phosphatidylserine, phosphatidic acid and cardiolipin. The majority of these fatty acyl residues were also identified in PE that resulted in the following composition: 28∶1/20∶2, 30∶2/18∶1, 28∶0/20∶2, 30∶2/20∶4 and 30∶3/20∶3. The PL of amoebae are significantly different in comparison to other cells: we describe here for the first time unusual, very long chain fatty acids with Δ5-unsaturation (30∶35,21,24 and 30∶221,24 localized exclusively in specific phospholipid classes of A. castellanii protozoa that could serve as specific biomarkers for the presence of

Phase separation in short-chain lecithin/gel-state long-chain lecithin aggregates

International Nuclear Information System (INIS)

Bian, J.; Roberts, M.F.

1990-01-01

Small bilayer particles for spontaneously from gel-state long-chain phospholipids such as dipalmitoylphosphatidylcholine and 0.2 mol fraction short-chain lecithins (e.g., diheptanoylphosphatidylcholine). When the particles are incubed at temperatures greater than the T m of the long-chain phosphatidylcholine (PC), the particles rapidly fuse (from 90-angstrom to ≥ 5,000-angstrom radius); this transition is reversible. A possible explanation for this behavior involves patching or phase separation of the short-chain component within the gel-state particle and randomization of both lipid species above T m . Differential scanning calorimetry, 1 H T 1 values of proteodiheptanoyl-PC in diheptanoyl-PC-d 26 /dipalmitoyl-PC-d 62 matrices of varying deuterium content, solid-state 2 H NMR spectroscopy as a function of temperature, and fluorescence pyrene excimer-to-monomer ratios as a function of mole fraction diheptanoyl-PC provide evidence that such phase separation must occur. These results are used to construct a phase diagram for the diheptanoyl-PC/dipalmitoyl-PC system, to propose detailed geometric models for the different lipid particles involved, and to understand phospholipase kinetics toward the different aggregates

Acyl coenzyme A thioesterase 7 regulates neuronal fatty acid metabolism to prevent neurotoxicity.

Science.gov (United States)

Ellis, Jessica M; Wong, G William; Wolfgang, Michael J

2013-05-01

Numerous neurological diseases are associated with dysregulated lipid metabolism; however, the basic metabolic control of fatty acid metabolism in neurons remains enigmatic. Here we have shown that neurons have abundant expression and activity of the long-chain cytoplasmic acyl coenzyme A (acyl-CoA) thioesterase 7 (ACOT7) to regulate lipid retention and metabolism. Unbiased and targeted metabolomic analysis of fasted mice with a conditional knockout of ACOT7 in the nervous system, Acot7(N-/-), revealed increased fatty acid flux into multiple long-chain acyl-CoA-dependent pathways. The alterations in brain fatty acid metabolism were concomitant with a loss of lean mass, hypermetabolism, hepatic steatosis, dyslipidemia, and behavioral hyperexcitability in Acot7(N-/-) mice. These failures in adaptive energy metabolism are common in neurodegenerative diseases. In agreement, Acot7(N-/-) mice exhibit neurological dysfunction and neurodegeneration. These data show that ACOT7 counterregulates fatty acid metabolism in neurons and protects against neurotoxicity.

Continuous recording of long-chain acyl-coenzyme A synthetase activity using fluorescently labeled bovine serum albumin

DEFF Research Database (Denmark)

Demant, Erland J.F.; Nystrøm, Birthe T.

2001-01-01

acyl-Coenzyme A, synthetase, activity assay, fluorescence recording, fatty acid probe, serum albumin, hydroxycoumarin, detergent, micelles, Pseudomonas fragi, rat liver microsomes......acyl-Coenzyme A, synthetase, activity assay, fluorescence recording, fatty acid probe, serum albumin, hydroxycoumarin, detergent, micelles, Pseudomonas fragi, rat liver microsomes...

Amino acid metabolism during exercise in trained rats: the potential role of carnitine in the metabolic fate of branched-chain amino acids.

Science.gov (United States)

Ji, L L; Miller, R H; Nagle, F J; Lardy, H A; Stratman, F W

1987-08-01

The influence of endurance training and an acute bout of exercise on plasma concentrations of free amino acids and the intermediates of branched-chain amino acid (BCAA) metabolism were investigated in the rat. Training did not affect the plasma amino acid levels in the resting state. Plasma concentrations of alanine (Ala), aspartic acid (Asp), asparagine (Asn), arginine (Arg), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), and valine (Val) were significantly lower, whereas glutamate (Glu), glycine (Gly), ornithine (Orn), tryptophan (Trp), tyrosine (Tyr), creatinine, urea, and ammonia levels were unchanged, after one hour of treadmill running in the trained rats. Plasma concentration of glutamine (Glu), the branched-chain keto acids (BCKA) and short-chain acyl carnitines were elevated with exercise. Ratios of plasma BCAA/BCKA were dramatically lowered by exercise in the trained rats. A decrease in plasma-free carnitine levels was also observed. These data suggest that amino acid metabolism is enhanced by exercise even in the trained state. BCAA may only be partially metabolized within muscle and some of their carbon skeletons are released into the circulation in forms of BCKA and short-chain acyl carnitines.

Role of long-chain fatty acyl-CoA esters in the regulation of metabolism and in cell signalling

DEFF Research Database (Denmark)

Færgeman, Nils J.; Knudsen, J

1997-01-01

(Ki for acyl-CoA is 5 nM) indicates strongly that the free cytosolic acyl-CoA concentration is below 5 nM under these conditions. Only a limited number of the reported experiments on the effects of acyl-CoA on cellular functions and enzymes have been carried out at low physiological concentrations...

Comprehensive in Vitro Analysis of Acyltransferase Domain Exchanges in Modular Polyketide Synthases and Its Application for Short-Chain Ketone Production

Energy Technology Data Exchange (ETDEWEB)

Yuzawa, Satoshi [Univ. of California, Berkeley, CA (United States); Deng, Kai [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Northen, Trent R. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Adams, Paul D. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Katz, Leonard [Univ. of California, Berkeley, CA (United States); Synthetic Biology Research Center, Emeryville, CA (United States); Keasling, Jay D. [Univ. of California, Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Synthetic Biology Research Center, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-08-22

Type I modular polyketide synthases (PKSs) are polymerases that utilize acyl-CoAs as substrates. Each polyketide elongation reaction is catalyzed by a set of protein domains called a module. Each module usually contains an acyltransferase (AT) domain, which determines the specific acyl-CoA incorporated into each condensation reaction. Although a successful exchange of individual AT domains can lead to the biosynthesis of a large variety of novel compounds, hybrid PKS modules often show significantly decreased activities. Using monomodular PKSs as models, we have systematically analyzed in this paper the segments of AT domains and associated linkers in AT exchanges in vitro and have identified the boundaries within a module that can be used to exchange AT domains while maintaining protein stability and enzyme activity. Importantly, the optimized domain boundary is highly conserved, which facilitates AT domain replacements in most type I PKS modules. To further demonstrate the utility of the optimized AT domain boundary, we have constructed hybrid PKSs to produce industrially important short-chain ketones. Our in vitro and in vivo analysis demonstrated production of predicted ketones without significant loss of activities of the hybrid enzymes. Finally, these results greatly enhance the mechanistic understanding of PKS modules and prove the benefit of using engineered PKSs as a synthetic biology tool for chemical production.

Association of acylated cationic decapeptides with dipalmitoylphosphatidylserine-dipalmitoyl- phosphatidylcholine lipid membranes

DEFF Research Database (Denmark)

Pedersen, T. B.; Sabra, Mads Christian; Frokjaer, Sven

2001-01-01

decapeptides that are N-terminally linked with C-2, C-8, and C-14 acyl chains contain four basic histidine residues in their identical amino acid sequence. A binding model, based on changes in the intrinsic fluorescent properties of the peptides upon association with the DPPC-DPPS membranes, is used...... DPPC-DPPS lipid mixture. The extent of peptide association deduced from the heat capacity measurements suggests a strong binding and membrane insertion of the C-14 acylated peptide in accordance with the fluorescence measurements....

Impact of fatty acyl composition and quantity of triglycerides on bioaccessibility of dietary carotenoids.

Science.gov (United States)

Huo, Tianyao; Ferruzzi, Mario G; Schwartz, Steven J; Failla, Mark L

2007-10-31

A carotenoid-rich salad meal with varying amounts and types of triglycerides (TG) was digested using simulated gastric and small intestinal conditions. Xanthophylls (lutein and zeaxanthin) and carotenes (alpha-carotene, beta-carotene, and lycopene) in chyme and micelle fraction were quantified to determine digestive stability and efficiency of micellarization (bioaccessibility). Micellarization of lutein (+zeaxanthin) exceeded that of alpha- and beta-carotenes, which was greater than that of lycopene for all test conditions. Micellarization of carotenes, but not lutein (+zeaxanthin), was enhanced (P structured TG (c18:1 > c8:0 > c4:0). The degree of unsaturation of c18 fatty acyl chains in TG added to the salad purée did not significantly alter the efficiency of micellarization of carotenoids. Relatively low amounts of triolein and canola oil (0.5-1%) were required for maximum micellarization of carotenes, but more oil (approximately 2.5%) was required when TG with medium chain saturated fatty acyl groups (e.g., trioctanoin and coconut oil) was added to the salad. Uptake of lutein and beta-carotene by Caco-2 cells also was examined by exposing cells to micelles generated during the simulated digestion of salad purée with either triolein or trioctanoin. Cell accumulation of beta-carotene was independent of fatty acyl composition of micelles, whereas lutein uptake was slightly, but significantly, increased from samples with digested triolein compared to trioctanoin. The results show that the in vitro transfer of alpha-carotene, beta-carotene, and lycopene from chyme to mixed micelles during digestion requires minimal (0.5-1%) lipid content in the meal and is affected by the length of fatty acyl chains but not the degree of unsaturation in TG. In contrast, fatty acyl chain length has limited if any impact on carotenoid uptake by small intestinal epithelial cells. These data suggest that the amount of TG in a typical meal does not limit the bioaccessibility of

Occurrence of fatty acid short-chain-alkyl esters in fruits of Celastraceae plants.

Science.gov (United States)

Sidorov, Roman A; Zhukov, Anatoly V; Pchelkin, Vasily P; Vereshchagin, Andrei G; Tsydendambaev, Vladimir D

2013-06-01

Small amounts of a mixture of fatty acid short-chain-alkyl esters (FASCAEs) were obtained from the fruits of twelve plant species of Celastraceae family, and in five of them the FASCAEs were present not only in the arils but also in the seeds. These mixtures contained 32 individual FASCAE species, which formed four separate fractions, viz. FA methyl, ethyl, isopropyl, and butyl esters (FAMEs, FAEEs, FAIPEs, and FABEs, resp.). The FASCAE acyl components included the residues of 16 individual C₁₄-C₂₄ saturated, mono-, di-, and trienoic FAs. Linoleic, oleic, and palmitic acids, and, in some cases, also α-linolenic acid predominated in FAMEs and FAEEs, while myristic acid was predominant in FAIPEs. It can be suggested that, in the fruit arils of some plant species, FAMEs and FAEEs were formed at the expense of a same FA pool characteristic of a given species and were strongly different from FAIPEs and FABEs esters regarding the mechanism of their biosynthesis. However, as a whole, the qualitative and quantitative composition of various FASCAE fractions, as well as their FA composition, varied considerably depending on various factors. Therefore, separate FASCAE fractions seem to be synthesized from different FA pools other than those used for triacylglycerol formation. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Anesthetic agents in patients with very long-chain acyl-coenzyme A dehydrogenase deficiency: a literature review.

Science.gov (United States)

Redshaw, Charlotte; Stewart, Catherine

2014-11-01

Very long-chain acyl-coenzyme A dehydrongenase deficiency (VLCADD) is a rare disorder of fatty acid metabolism that renders sufferers susceptible to hypoglycemia, liver failure, cardiomyopathy, and rhabdomyolysis. The literature about the management of these patients is hugely conflicting, suggesting that both propofol and volatile anesthesia should be avoided. We have reviewed the literature and have concluded that the source papers do not support the statements that volatile anesthetic agents are unsafe. The reports on rhabdomyolysis secondary to anesthesia appear to be due to inadequate supply of carbohydrate not volatile agents. Catabolism must be avoided with minimal fasting, glucose infusions based on age and weight, and attenuation of emotional and physical stress. General anesthesia appears to be protective of stress-induced catabolism and may offer benefits in children and anxious patients over regional anesthesia. Propofol has not been demonstrated to be harmful in VLCADD but is presented in an emulsion containing very long-chain fatty acids which can cause organ lipidosis and itself can inhibit mitochondrial fatty acid metabolism. It is therefore not recommended. Suxamethonium-induced myalgia may mimic symptoms of rhabdomyolysis and cause raised CK therefore should be avoided. Opioids, NSAIDS, regional anesthesia, and local anesthetic techniques have all been used without complication. © 2014 John Wiley & Sons Ltd.

Human carbonyl reductase 1 participating in intestinal first-pass drug metabolism is inhibited by fatty acids and acyl-CoAs.

Science.gov (United States)

Hara, Akira; Endo, Satoshi; Matsunaga, Toshiyuki; El-Kabbani, Ossama; Miura, Takeshi; Nishinaka, Toru; Terada, Tomoyuki

2017-08-15

Human carbonyl reductase 1 (CBR1), a member of the short-chain dehydrogenase/reductase (SDR) superfamily, reduces a variety of carbonyl compounds including endogenous isatin, prostaglandin E 2 and 4-oxo-2-nonenal. It is also a major non-cytochrome P450 enzyme in the phase I metabolism of carbonyl-containing drugs, and is highly expressed in the intestine. In this study, we found that long-chain fatty acids and their CoA ester derivatives inhibit CBR1. Among saturated fatty acids, myristic, palmitic and stearic acids were inhibitory, and stearic acid was the most potent (IC 50 9µM). Unsaturated fatty acids (oleic, elaidic, γ-linolenic and docosahexaenoic acids) and acyl-CoAs (palmitoyl-, stearoyl- and oleoyl-CoAs) were more potent inhibitors (IC 50 1.0-2.5µM), and showed high inhibitory selectivity to CBR1 over its isozyme CBR3 and other SDR superfamily enzymes (DCXR and DHRS4) with CBR activity. The inhibition by these fatty acids and acyl-CoAs was competitive with respect to the substrate, showing the K i values of 0.49-1.2µM. Site-directed mutagenesis of the substrate-binding residues of CBR1 suggested that the interactions between the fatty acyl chain and the enzyme's Met141 and Trp229 are important for the inhibitory selectivity. We also examined CBR1 inhibition by oleic acid in cellular levels: The fatty acid effectively inhibited CBR1-mediated 4-oxo-2-nonenal metabolism in colon cancer DLD1 cells and increased sensitivity to doxorubicin in the drug-resistant gastric cancer MKN45 cells that highly express CBR1. The results suggest a possible new food-drug interaction through inhibition of CBR1-mediated intestinal first-pass drug metabolism by dietary fatty acids. Copyright © 2017 Elsevier Inc. All rights reserved.

Commelinid Monocotyledon Lignins Are Acylated by p-Coumarate1[OPEN

Science.gov (United States)

Free, Heather C.A.; Smith, Bronwen G.

2018-01-01

Commelinid monocotyledons are a monophyletic clade differentiated from other monocotyledons by the presence of cell wall-bound ferulate and p-coumarate. The Poaceae, or grass family, is a member of this group, and most of the p-coumarate in the cell walls of this family acylates lignin. Here, we isolated and examined lignified cell wall preparations from 10 species of commelinid monocotyledons from nine families other than Poaceae, including species from all four commelinid monocotyledon orders (Poales, Zingiberales, Commelinales, and Arecales). We showed that, as in the Poaceae, lignin-linked p-coumarate occurs exclusively on the hydroxyl group on the γ-carbon of lignin unit side chains, mostly on syringyl units. Although the mechanism of acylation has not been studied directly in these species, it is likely to be similar to that in the Poaceae and involve BAHD acyl-coenzyme A:monolignol transferases. PMID:29724771

N-Acylated and d Enantiomer Derivatives of a Nonamer Core Peptide of Lactoferricin B Showing Improved Antimicrobial Activity

OpenAIRE

Wakabayashi, Hiroyuki; Matsumoto, Hiroshi; Hashimoto, Koichi; Teraguchi, Susumu; Takase, Mitsunori; Hayasawa, Hirotoshi

1999-01-01

N-acylated or d enantiomer peptide derivatives based on the sequence RRWQWRMKK in lactoferricin B demonstrated antimicrobial activities greater than those of lactoferricin B against bacteria and fungi. The most potent peptide, conjugated with an 11-carbon-chain acyl group, showed two to eight times lower MIC than lactoferricin B.

N-Acylated and D enantiomer derivatives of a nonamer core peptide of lactoferricin B showing improved antimicrobial activity.

Science.gov (United States)

Wakabayashi, H; Matsumoto, H; Hashimoto, K; Teraguchi, S; Takase, M; Hayasawa, H

1999-05-01

N-acylated or D enantiomer peptide derivatives based on the sequence RRWQWRMKK in lactoferricin B demonstrated antimicrobial activities greater than those of lactoferricin B against bacteria and fungi. The most potent peptide, conjugated with an 11-carbon-chain acyl group, showed two to eight times lower MIC than lactoferricin B.

SIRT3 and SIRT5 regulate the enzyme activity and cardiolipin binding of very long-chain acyl-CoA dehydrogenase.

Directory of Open Access Journals (Sweden)

Yuxun Zhang

Full Text Available SIRT3 and SIRT5 have been shown to regulate mitochondrial fatty acid oxidation but the molecular mechanisms behind the regulation are lacking. Here, we demonstrate that SIRT3 and SIRT5 both target human very long-chain acyl-CoA dehydrogenase (VLCAD, a key fatty acid oxidation enzyme. SIRT3 deacetylates and SIRT5 desuccinylates K299 which serves to stabilize the essential FAD cofactor in the active site. Further, we show that VLCAD binds strongly to cardiolipin and isolated mitochondrial membranes via a domain near the C-terminus containing lysines K482, K492, and K507. Acetylation or succinylation of these residues eliminates binding of VLCAD to cardiolipin. SIRT3 deacetylates K507 while SIRT5 desuccinylates K482, K492, and K507. Sirtuin deacylation of recombinant VLCAD rescues membrane binding. Endogenous VLCAD from SIRT3 and SIRT5 knockout mouse liver shows reduced binding to cardiolipin. Thus, SIRT3 and SIRT5 promote fatty acid oxidation by converging upon VLCAD to promote its activity and membrane localization. Regulation of cardiolipin binding by reversible lysine acylation is a novel mechanism that is predicted to extrapolate to other metabolic proteins that localize to the inner mitochondrial membrane.

Mouse myeloma cells that make short immunoglobulin heavy chains: pleiotropic effects on glycosylation and chain assembly

OpenAIRE

1984-01-01

Two variants in immunoglobulin heavy chain production, derived from the MPC 11 mouse myeloma cell line, make short heavy (H) chains with identical precise deletions of the CH3 domain. The CH3 domain is expressed in the H chain mRNA from both variants. Although in vitro translation of this mRNA produces one H chain species, deleted heavy chains are secreted as heavy-light (HL) and H2L2 moieties in contrast to MPC 11, which secretes only H2L2 . The heavy chains of HL apparently contain more car...

Efficient odd straight medium chain free fatty acid production by metabolically engineered Escherichia coli.

Science.gov (United States)

Wu, Hui; San, Ka-Yiu

2014-11-01

Free fatty acids (FFAs) can be used as precursors for the production of biofuels or chemicals. Different composition of FFAs will be useful for further modification of the biofuel/biochemical quality. Microbial biosynthesis of even chain FFAs can be achieved by introducing an acyl-acyl carrier protein thioesterase gene into E. coli. In this study, odd straight medium chain FFAs production was investigated by using metabolic engineered E. coli carrying acyl-ACP thioesterase (TE, Ricinus communis), propionyl-CoA synthase (Salmonella enterica), and β-ketoacyl-acyl carrier protein synthase III (four different sources) with supplement of extracellular propionate. By using these metabolically engineered E. coli, significant quantity of C13 and C15 odd straight-chain FFAs could be produced from glucose and propionate. The highest concentration of total odd straight chain FFAs attained was 1205 mg/L by the strain HWK201 (pXZ18, pBHE2), and 85% of the odd straight chain FFAs was C15. However, the highest percentage of odd straight chain FFAs was achieved by the strain HWK201 (pXZ18, pBHE3) of 83.2% at 48 h. This strategy was also applied successfully in strains carrying different TE, such as the medium length acyl-ACP thioesterase gene from Umbellularia californica. C11 and C13 became the major odd straight-chain FFAs. © 2014 Wiley Periodicals, Inc.

Fatty acyl-CoA reductases of birds

Directory of Open Access Journals (Sweden)

Hellenbrand Janine

2011-12-01

Full Text Available Abstract Background Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba, domestic chicken (Gallus gallus domesticus and domestic goose (Anser anser domesticus. Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis.

Fatty acyl-CoA reductases of birds

Science.gov (United States)

2011-01-01

Background Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR) catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba), domestic chicken (Gallus gallus domesticus) and domestic goose (Anser anser domesticus). Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis. PMID:22151413

Molecular cloning and sequence analysis of complementary DNA encoding rat mammary gland medium-chain S-acyl fatty acid synthetase thio ester hydrolase

International Nuclear Information System (INIS)

Safford, R.; de Silva, J.; Lucas, C.

1987-01-01

Poly(A) + RNA from pregnant rat mammary glands was size-fractionated by sucrose gradient centrifugation, and fractions enriched in medium-chain S-acyl fatty acid synthetase thio ester hydrolase (MCH) were identified by in vitro translation and immunoprecipitation. A cDNA library was constructed, in pBR322, from enriched poly(A) + RNA and screened with two oligonucleotide probes deduced from rat MCH amino acid sequence data. Cross-hybridizing clones were isolated and found to contain cDNA inserts ranging from ∼ 1100 to 1550 base pairs (bp). A 1550-bp cDNA insert, from clone 43H09, was confirmed to encode MCH by hybrid-select translation/immunoprecipitation studies and by comparison of the amino acid sequence deduced from the DNA sequence of the clone to the amino acid sequence of the MCH peptides. Northern blot analysis revealed the size of the MCH mRNA to be 1500 nucleotides, and it is therefore concluded that the 1550-bp insert (including G x C tails) of clone 43H09 represents a full- or near-full-length copy of the MCH gene. The rat MCH sequence is the first reported sequence of a thioesterase from a mammalian source, but comparison of the deduced amino acid sequences of MCH and the recently published mallard duck medium-chain S-acyl fatty acid synthetase thioesterase reveals significant homology. In particular, a seven amino acid sequence containing the proposed active serine of the duck thioesterase is found to be perfectly conserved in rat MCH

Acyl-CoA-binding protein/diazepam-binding inhibitor gene and pseudogenes

DEFF Research Database (Denmark)

Mandrup, S; Hummel, R; Ravn, S

1992-01-01

Acyl-CoA-binding protein (ACBP) is a 10 kDa protein isolated from bovine liver by virtue of its ability to bind and induce the synthesis of medium-chain acyl-CoA esters. Surprisingly, it turned out to be identical to a protein named diazepam-binding Inhibitor (DBI) claimed to be an endogenous mod...... have molecularly cloned and characterized the ACBP/DBI gene family in rat. The rat ACBP/DBI gene family comprises one expressed gene and four processed pseudogenes of which one was shown to exist in two allelic forms. The expressed gene is organized into four exons and three introns...

Effect of short-chain branching on interfacial polymer structure and dynamics under shear flow.

Science.gov (United States)

Jeong, Sohdam; Kim, Jun Mo; Cho, Soowon; Baig, Chunggi

2017-11-22

We present a detailed analysis on the effect of short-chain branches on the structure and dynamics of interfacial chains using atomistic nonequilibrium molecular dynamics simulations of confined polyethylene melts in a wide range of shear rates. The intrinsically fast random motions of the short branches constantly disturb the overall chain conformation, leading to a more compact and less deformed chain structure of the short-chain branched (SCB) polymer against the imposed flow field in comparison with the corresponding linear polymer. Moreover, such highly mobile short branches along the backbone of the SCB polymer lead to relatively weaker out-of-plane wagging dynamics of interfacial chains, with highly curvy backbone structures in the intermediate flow regime. In conjunction with the contribution of short branches (as opposed to that of the backbone) to the total interfacial friction between the chains and the wall, the SCB polymer shows a nearly constant behavior in the degree of slip (d s ) with respect to shear rate in the weak-to-intermediate flow regimes. On the contrary, in the strong flow regime where irregular chain rotation and tumbling dynamics occur via intensive dynamical collisions between interfacial chains and the wall, an enhancement effect on the chain detachment from the wall, caused by short branches, leads to a steeper increase in d s for the SCB polymer than for the linear polymer. Remarkably, the SCB chains at the interface exhibit two distinct types of rolling mechanisms along the backbone, with a half-dumbbell mesoscopic structure at strong flow fields, in addition to the typical hairpin-like tumbling behavior displayed by the linear chains.

Acyl carrier proteins from sunflower (Helianthus annuus L.) seeds and their influence on FatA and FatB acyl-ACP thioesterase activities.

Science.gov (United States)

Aznar-Moreno, Jose A; Venegas-Calerón, Mónica; Martínez-Force, Enrique; Garcés, Rafael; Salas, Joaquín J

2016-08-01

The kinetics of acyl-ACP thioesterases from sunflower importantly changed when endogenous ACPs were used. Sunflower FatB was much more specific towards saturated acyl-ACPs when assayed with them. Acyl carrier proteins (ACPs) are small (~9 kDa), soluble, acidic proteins involved in fatty acid synthesis in plants and bacteria. ACPs bind to fatty acids through a thioester bond, generating the acyl-ACP lipoproteins that are substrates for fatty acid synthase (FAS) complexes, and that are required for fatty acid chain elongation, acting as important intermediates in de novo fatty acid synthesis in plants. Plants, usually express several ACP isoforms with distinct functionalities. We report here the cloning of three ACPs from developing sunflower seeds: HaACP1, HaACP2, and HaACP3. These proteins were plastidial ACPs expressed strongly in seeds, and as such they are probably involved in the synthesis of sunflower oil. The recombinant sunflower ACPs were expressed in bacteria but they were lethal to the prokaryote host. Thus, they were finally produced using the GST gene fusion system, which allowed the apo-enzyme to be produced and later activated to the holo form. Radiolabelled acyl-ACPs from the newly cloned holo-ACP forms were also synthesized and used to characterize the activity of recombinant sunflower FatA and FatB thioesterases, important enzymes in plant fatty acids synthesis. The activity of these enzymes changed significantly when the endogenous ACPs were used. Thus, FatA importantly increased its activity levels, whereas FatB displayed a different specificity profile, with much high activity levels towards saturated acyl-CoA derivatives. All these data pointed to an important influence of the ACP moieties on the activity of enzymes involved in lipid synthesis.

De novo fatty acid biosynthesis and elongation in very long-chain acyl-CoA dehydrogenase-deficient mice supplemented with odd or even medium-chain fatty acids.

Science.gov (United States)

Tucci, Sara; Behringer, Sidney; Spiekerkoetter, Ute

2015-11-01

An even medium-chain triglyceride (MCT)-based diet is the mainstay of treatment in very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (VLCADD). Previous studies with magnetic resonance spectroscopy have shown an impact of MCT on the average fatty acid chain length in abdominal fat. We therefore assume that medium-chain fatty acids (MCFAs) are elongated and accumulate in tissue as long-chain fatty acids. In this study, we explored the hepatic effects of long-term supplementation with MCT or triheptanoin, an odd-chain C7-based triglyceride, in wild-type and VLCAD-deficient (VLCAD(-/-) ) mice after 1 year of supplementation as compared with a control diet. The de novo biosynthesis and elongation of fatty acids, and peroxisomal β-oxidation, were quantified by RT-PCR. This was followed by a comprehensive analysis of hepatic and cardiac fatty acid profiles by GC-MS. Long-term application of even and odd MCFAs strongly induced de novo biosynthesis and elongation of fatty acids in both wild-type and VLCAD(-/-) mice, leading to an alteration of the hepatic fatty acid profiles. We detected de novo-synthesized and elongated fatty acids, such as heptadecenoic acid (C17:1n9), eicosanoic acid (C20:1n9), erucic acid (C22:1n9), and mead acid (C20:3n9), that were otherwise completely absent in mice under control conditions. In parallel, the content of monounsaturated fatty acids was massively increased. Furthermore, we observed strong upregulation of peroxisomal β-oxidation in VLCAD(-/-) mice, especially when they were fed an MCT diet. Our data raise the question of whether long-term MCFA supplementation represents the most efficient treatment in the long term. Studies on the hepatic toxicity of triheptanoin are still ongoing. © 2015 FEBS.

Acylation of proteins with myristic acid occurs cotranslationally

International Nuclear Information System (INIS)

Wilcox, C.; Hu, J.S.; Olson, E.N.

1987-01-01

Several proteins of viral and cellular origin are acylated with myristic acid early during their biogenesis. To investigate the possibility that myristylation occurred cotranslationally, the BC 3 H1 muscle cell line, which contains a broad array of myristylated proteins, was pulse-labeled with [ 3 H]myristic acid. Nascent polypeptide chains covalently associated with transfer RNA were isolated subsequently by ion-exchange chromatography. [ 3 H]Myristate was attached to nascent chains through an amide linkage and was identified by thin-layer chromatography after its release from nascent chains by acid methanolysis. Inhibition of cellular protein synthesis with puromycin resulted in cessation of [ 3 H]myristate-labeling of nascent chains, in agreement with the dependence of this modification on protein synthesis in vivo. These data represent a direct demonstration that myristylation of proteins is a cotranslational modification

Butyrate decreases its own oxidation in colorectal cancer cells through inhibition of histone deacetylases.

Science.gov (United States)

Han, Anna; Bennett, Natalie; Ahmed, Bettaieb; Whelan, Jay; Donohoe, Dallas R

2018-06-05

Colorectal cancer is characterized by an increase in the utilization of glucose and a diminishment in the oxidation of butyrate, which is a short chain fatty acid. In colorectal cancer cells, butyrate inhibits histone deacetylases to increase the expression of genes that slow the cell cycle and induce apoptosis. Understanding the mechanisms that contribute to the metabolic shift away from butyrate oxidation in cancer cells is important in in understanding the beneficial effects of the molecule toward colorectal cancer. Here, we demonstrate that butyrate decreased its own oxidation in cancerous colonocytes. Butyrate lowered the expression of short chain acyl-CoA dehydrogenase, an enzyme that mediates the oxidation of short-chain fatty acids. Butyrate does not alter short chain acyl-CoA dehydrogenase levels in non-cancerous colonocytes. Trichostatin A, a structurally unrelated inhibitor of histone deacetylases, and propionate also decreased the level of short chain acyl-CoA dehydrogenase, which alluded to inhibition of histone deacetylases as a part of the mechanism. Knockdown of histone deacetylase isoform 1, but not isoform 2 or 3, inhibited the ability of butyrate to decrease short chain acyl-CoA dehydrogenase expression. This work identifies a mechanism by which butyrate selective targets colorectal cancer cells to reduce its own metabolism.

The R117A variant of the Escherichia coli transacylase FabD synthesizes novel acyl-(acyl carrier proteins).

Science.gov (United States)

Marcella, Aaron M; Barb, Adam W

2017-12-01

The commercial impact of fermentation systems producing novel and biorenewable chemicals will flourish with the expansion of enzymes engineered to synthesize new molecules. Though a small degree of natural variability exists in fatty acid biosynthesis, the molecular space accessible through enzyme engineering is fundamentally limitless. Prokaryotic fatty acid biosynthesis enzymes build carbon chains on a functionalized acyl carrier protein (ACP) that provides solubility, stability, and a scaffold for interactions with the synthetic enzymes. Here, we identify the malonyl-coenzyme A (CoA)/holo-ACP transacylase (FabD) from Escherichia coli as a platform enzyme for engineering to diversify microbial fatty acid biosynthesis. The FabD R117A variant produced novel ACP-based primer and extender units for fatty acid biosynthesis. Unlike the wild-type enzyme that is highly specific for malonyl-CoA to produce malonyl-ACP, the R117A variant synthesized acetyl-ACP, succinyl-ACP, isobutyryl-ACP, 2-butenoyl-ACP, and β-hydroxybutyryl-ACP among others from holo-ACP and the corresponding acyl-CoAs with specific activities from 3.7 to 120 nmol min -1  mg -1 . FabD R117A maintained K M values for holo-ACP (~ 40 μM) and displayed small changes in K M for acetoacetyl-CoA (110 ± 30 μM) and acetyl-CoA (200 ± 70 μM) when compared to malonyl-CoA (80 ± 30 μM). FabD R117A represents a novel catalyst that synthesizes a broad range of acyl-acyl-ACPs.

Ab initio I-V characteristics of short C-20 chains

DEFF Research Database (Denmark)

Roland, C.; Larade, B.; Taylor, Jeremy Philip

2002-01-01

We have calculated the I-V characteristics of short chains of C-20 molecular cages between Al and Au leads with an ab initio formalism. The results indicate that a linear chain of such molecules acts primarily as metallic nanowires. The transmission, however, depends sensitively both...

A targeted metabolomic protocol for short-chain fatty acids and branched-chain amino acids

OpenAIRE

Zheng, Xiaojiao; Qiu, Yunping; Zhong, Wei; Baxter, Sarah; Su, Mingming; Li, Qiong; Xie, Guoxiang; Ore, Brandon M.; Qiao, Shanlei; Spencer, Melanie D.; Zeisel, Steven H.; Zhou, Zhanxiang; Zhao, Aihua; Jia, Wei

2013-01-01

Research in obesity and metabolic disorders that involve intestinal microbiota demands reliable methods for the precise measurement of the short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) concentration. Here, we report a rapid method of simultaneously determining SCFAs and BCAAs in biological samples using propyl chloroformate (PCF) derivatization followed by gas chromatography mass spectrometry (GC-MS) analysis. A one-step derivatization using 100 µL of PCF in a reactio...

Biodiesel production from triolein and short chain alcohols through biocatalysis.

Science.gov (United States)

Salis, Andrea; Pinna, Marcella; Monduzzi, Maura; Solinas, Vincenzo

2005-09-29

Oleic acid alkyl esters (biodiesel) were synthesised by biocatalysis in solvent-free conditions. Different commercial immobilised lipases, namely Candida antarctica B, Rizhomucor miehei, and Pseudomonas cepacia, were tested towards the reaction between triolein and butanol to produce butyl oleate. Pseudomonas cepacia lipase resulted to be the most active enzyme reaching 100% of conversion after 6h. Different operative conditions such as reaction temperature, water activity, and reagent stoichiometric ratio were investigated and optimised. These conditions were then used to investigate the effect of linear and branched short chain alcohols. Methanol and 2-butanol were the worst alcohols: the former, probably, due to its low miscibility with the oil and the latter because secondary alcohols usually are less reactive than primary alcohols. Conversely, linear and branched primary alcohols with short alkyl chains (C(2)--C(4)) showed high reaction rate and conversion. A mixture of linear and branched short chain alcohols that mimics the residual of ethanol distillation (fusel oil) was successfully used for oleic acid ester synthesis. These compounds are important in biodiesel mixtures since they improve low temperature properties.

Sunflower (Helianthus annuus) long-chain acyl-coenzyme A synthetases expressed at high levels in developing seeds.

Science.gov (United States)

Aznar-Moreno, Jose A; Venegas Calerón, Mónica; Martínez-Force, Enrique; Garcés, Rafael; Mullen, Robert; Gidda, Satinder K; Salas, Joaquín J

2014-03-01

Long chain fatty acid synthetases (LACSs) activate the fatty acid chains produced by plastidial de novo biosynthesis to generate acyl-CoA derivatives, important intermediates in lipid metabolism. Oilseeds, like sunflower, accumulate high levels of triacylglycerols (TAGs) in their seeds to nourish the embryo during germination. This requires that sunflower seed endosperm supports very active glycerolipid synthesis during development. Sunflower seed plastids produce large amounts of fatty acids, which must be activated through the action of LACSs, in order to be incorporated into TAGs. We cloned two different LACS genes from developing sunflower endosperm, HaLACS1 and HaLACS2, which displayed sequence homology with Arabidopsis LACS9 and LACS8 genes, respectively. These genes were expressed at high levels in developing seeds and exhibited distinct subcellular distributions. We generated constructs in which these proteins were fused to green fluorescent protein and performed transient expression experiments in tobacco cells. The HaLACS1 protein associated with the external envelope of tobacco chloroplasts, whereas HaLACS2 was strongly bound to the endoplasmic reticulum. Finally, both proteins were overexpressed in Escherichia coli and recovered as active enzymes in the bacterial membranes. Both enzymes displayed similar substrate specificities, with a very high preference for oleic acid and weaker activity toward stearic acid. On the basis of our findings, we discuss the role of these enzymes in sunflower oil synthesis. © 2013 Scandinavian Plant Physiology Society.

Phosphorylation and Acetylation of Acyl-CoA Synthetase- I

DEFF Research Database (Denmark)

Frahm, Jennifer L; Li, Lei O; Grevengoed, Trisha J

2011-01-01

Long chain acyl-CoA synthetase 1 (ACSL1) contributes 50 to 90% of total ACSL activity in liver, adipose tissue, and heart and appears to direct the use of long chain fatty acids for energy. Although the functional importance of ACSL1 is becoming clear, little is understood about its post...... and acetylated amino acids by mass spectrometry. We then compared these results to the post-translational modifications observed in vivo in liver and brown adipose tissue after mice were fasted or exposed to a cold environment. We identified universal N-terminal acetylation, 15 acetylated lysines, and 25...

Isolated 2-methylbutyrylglycinuria caused by short/branched-chain acyl-CoA dehydrogenase deficiency: identification of a new enzyme defect, resolution of its molecular basis, and evidence for distinct acyl-CoA dehydrogenases in isoleucine and valine metabolism

NARCIS (Netherlands)

Andresen, B. S.; Christensen, E.; Corydon, T. J.; Bross, P.; Pilgaard, B.; Wanders, R. J.; Ruiter, J. P.; Simonsen, H.; Winter, V.; Knudsen, I.; Schroeder, L. D.; Gregersen, N.; Skovby, F.

2000-01-01

Acyl-CoA dehydrogenase (ACAD) defects in isoleucine and valine catabolism have been proposed in clinically diverse patients with an abnormal pattern of metabolites in their urine, but they have not been proved enzymatically or genetically, and it is unknown whether one or two ACADs are involved. We

Phase behavior and nanoscale structure of phospholipid membranes incorporated with acylated C-14-peptides

DEFF Research Database (Denmark)

Pedersen, T.B.; Kaasgaard, Thomas; Jensen, M.O.

2005-01-01

The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated...... peptide, which is a synthetic decapeptide N-terminally linked to a C-14 acyl chain (C-14-peptide), is incorporated into DPPC bilayers in amounts ranging from 0-20 mol %. The calorimetric scans of the two-component system demonstrate a distinct influence of the C-14-peptide on the lipid bilayer...... gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C-14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10...

Effect of Acylglycerol Composition and Fatty Acyl Chain Length on Lipid Digestion in pH-Stat Digestion Model and Simulated In Vitro Digestion Model.

Science.gov (United States)

Qi, Jin F; Jia, Cai H; Shin, Jung A; Woo, Jeong M; Wang, Xiang Y; Park, Jong T; Hong, Soon T; Lee, K-T

2016-02-01

In this study, a pH-stat digestion model and a simulated in vitro digestion model were employed to evaluate the digestion degree of lipids depending on different acylglycerols and acyl chain length (that is, diacylglycerol [DAG] compared with soybean oil representing long-chain triacylglycerol compared with medium-chain triacylglycerol [MCT]). In the pH-stat digestion model, differences were observed among the digestion degrees of 3 oils using digestion rate (k), digestion half-time (t1/2 ), and digestion extent (Φmax). The results showed the digestion rate order was MCT > soybean oil > DAG. Accordingly, the order of digestion half-times was MCT digestion model, digestion rates (k') and digestion half-times (t'1/2 ) were also obtained and the results showed a digestion rate order of MCT (k' = 0.068 min(-1) ) > soybean oil (k' = 0.037 min(-1) ) > DAG (k' = 0.024 min(-1) ). Consequently, the order of digestion half-times was MCT (t'1/2 = 10.20 min) digested faster than soybean oil, and that soybean oil was digested faster than DAG. © 2015 Institute of Food Technologists®

SUSTAINABILITY OF SHORT FOOD SUPPLY CHAINS: ANALYSIS OF RAW MATERIAL SUPPLY IN MILAN PUBLIC SCHOOL CATERING

Directory of Open Access Journals (Sweden)

G. D’Anna

2009-09-01

Full Text Available The demand of short food supply chains is becoming more pressing by consumers, especially in the largest school catering. The implementation of the short chain in a large catering company of Milan, is described in this practical contribution. Several aspects of short food chains sustainability: legal, commercial and economic sustainability, hygienic and gastronomic sustainability, are discussed.

Overexpression of human fatty acid transport protein 2/very long chain acyl-CoA synthetase 1 (FATP2/Acsvl1) reveals distinct patterns of trafficking of exogenous fatty acids

Energy Technology Data Exchange (ETDEWEB)

Melton, Elaina M. [Department of Biochemistry, University of Nebraska, Lincoln, NE (United States); Center for Cardiovascular Sciences, Albany Medical College, Albany, NY (United States); Cerny, Ronald L. [Department of Chemistry, University of Nebraska, Lincoln, NE (United States); DiRusso, Concetta C. [Department of Biochemistry, University of Nebraska, Lincoln, NE (United States); Black, Paul N., E-mail: pblack2@unl.edu [Department of Biochemistry, University of Nebraska, Lincoln, NE (United States)

2013-11-01

Highlights: •Roles of FATP2 in fatty acid transport/activation contribute to lipid homeostasis. •Use of 13C- and D-labeled fatty acids provide novel insights into FATP2 function. •FATP2-dependent trafficking of FA into phospholipids results in distinctive profiles. •FATP2 functions in the transport and activation pathways for exogenous fatty acids. -- Abstract: In mammals, the fatty acid transport proteins (FATP1 through FATP6) are members of a highly conserved family of proteins, which function in fatty acid transport proceeding through vectorial acylation and in the activation of very long chain fatty acids, branched chain fatty acids and secondary bile acids. FATP1, 2 and 4, for example directly function in fatty acid transport and very long chain fatty acids activation while FATP5 does not function in fatty acid transport but activates secondary bile acids. In the present work, we have used stable isotopically labeled fatty acids differing in carbon length and saturation in cells expressing FATP2 to gain further insights into how this protein functions in fatty acid transport and intracellular fatty acid trafficking. Our previous studies showed the expression of FATP2 modestly increased C16:0-CoA and C20:4-CoA and significantly increased C18:3-CoA and C22:6-CoA after 4 h. The increases in C16:0-CoA and C18:3-CoA suggest FATP2 must necessarily partner with a long chain acyl CoA synthetase (Acsl) to generate C16:0-CoA and C18:3-CoA through vectorial acylation. The very long chain acyl CoA synthetase activity of FATP2 is consistent in the generation of C20:4-CoA and C22:6-CoA coincident with transport from their respective exogenous fatty acids. The trafficking of exogenous fatty acids into phosphatidic acid (PA) and into the major classes of phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidyserine (PS)) resulted in distinctive profiles, which changed with the expression of FATP2. The

Overexpression of human fatty acid transport protein 2/very long chain acyl-CoA synthetase 1 (FATP2/Acsvl1) reveals distinct patterns of trafficking of exogenous fatty acids

International Nuclear Information System (INIS)

Melton, Elaina M.; Cerny, Ronald L.; DiRusso, Concetta C.; Black, Paul N.

2013-01-01

Highlights: •Roles of FATP2 in fatty acid transport/activation contribute to lipid homeostasis. •Use of 13C- and D-labeled fatty acids provide novel insights into FATP2 function. •FATP2-dependent trafficking of FA into phospholipids results in distinctive profiles. •FATP2 functions in the transport and activation pathways for exogenous fatty acids. -- Abstract: In mammals, the fatty acid transport proteins (FATP1 through FATP6) are members of a highly conserved family of proteins, which function in fatty acid transport proceeding through vectorial acylation and in the activation of very long chain fatty acids, branched chain fatty acids and secondary bile acids. FATP1, 2 and 4, for example directly function in fatty acid transport and very long chain fatty acids activation while FATP5 does not function in fatty acid transport but activates secondary bile acids. In the present work, we have used stable isotopically labeled fatty acids differing in carbon length and saturation in cells expressing FATP2 to gain further insights into how this protein functions in fatty acid transport and intracellular fatty acid trafficking. Our previous studies showed the expression of FATP2 modestly increased C16:0-CoA and C20:4-CoA and significantly increased C18:3-CoA and C22:6-CoA after 4 h. The increases in C16:0-CoA and C18:3-CoA suggest FATP2 must necessarily partner with a long chain acyl CoA synthetase (Acsl) to generate C16:0-CoA and C18:3-CoA through vectorial acylation. The very long chain acyl CoA synthetase activity of FATP2 is consistent in the generation of C20:4-CoA and C22:6-CoA coincident with transport from their respective exogenous fatty acids. The trafficking of exogenous fatty acids into phosphatidic acid (PA) and into the major classes of phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidyserine (PS)) resulted in distinctive profiles, which changed with the expression of FATP2. The

Design and preparation of bi-functionalized short-chain modified zwitterionic nanoparticles.

Science.gov (United States)

Hu, Fenglin; Chen, Kaimin; Xu, Hong; Gu, Hongchen

2018-05-01

An ideal nanomaterial for use in the bio-medical field should have a distinctive surface capable of effectively preventing nonspecific protein adsorption and identifying target bio-molecules. Recently, the short-chain zwitterion strategy has been suggested as a simple and novel approach to create outstanding anti-fouling surfaces. In this paper, the carboxyl end group of short-chain zwitterion-coated silica nanoparticles (SiO 2 -ZWS) was found to be difficult to functionalize via a conventional EDC/NHS strategy due to its rapid hydrolysis side-reactions. Hence, a series of bi-functionalized silica nanoparticles (SiO 2 -ZWS/COOH) were designed and prepared by controlling the molar ratio of 3-aminopropyltriethoxysilane (APTES) to short-chain zwitterionic organosiloxane (ZWS) in order to achieve above goal. The synthesized SiO 2 -ZWS/COOH had similar excellent anti-fouling properties compared with SiO 2 -ZWS, even in 50% fetal bovine serum characterized by DLS and turbidimetric titration. Subsequently, SiO 2 -ZWS/COOH 5/1 was chosen as a representative and then demonstrated higher detection signal intensity and more superior signal-to-noise ratios compare with the pure SiO 2 -COOH when they were used as a bio-carrier for chemiluminescence enzyme immunoassay (CLEIA). These unique bi-functionalized silica nanoparticles have many potential applications in the diagnostic and therapeutic fields. Reducing nonspecific protein adsorption and enhancing the immobilized efficiency of specific bio-probes are two of the most important issues for bio-carriers, particularly for a nanoparticle based bio-carrier. Herein, we designed and prepared a bi-functional nanoparticle with anti-fouling property and bio conjugation capacity for further bioassay by improving the short-chain zwitterionic modification strategy we have proposed previously. The heterogeneous surface of this nanoparticle showed effective anti-fouling properties both in model protein solutions and fetal bovine serum

Quantifying Short-Chain Chlorinated Paraffin Congener Groups.

Science.gov (United States)

Yuan, Bo; Bogdal, Christian; Berger, Urs; MacLeod, Matthew; Gebbink, Wouter A; Alsberg, Tomas; de Wit, Cynthia A

2017-09-19

Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a "congener group" C n Cl m . Recently, we resolved individual C n Cl m by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying C n Cl m by introducing C n Cl m specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each C n Cl m are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were -0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q-Orbitrap-MS. C n Cl m concentrations determined with the three instruments were highly correlated (R 2 > 0.90) with each other.

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Directory of Open Access Journals (Sweden)

Tor E. Kristensen

2015-04-01

Full Text Available Amino acids, whether natural, semisynthetic or synthetic, are among the most important and useful chiral building blocks available for organic chemical synthesis. In principle, they can function as inexpensive, chiral and densely functionalized starting materials. On the other hand, the use of amino acid starting materials routinely necessitates protective group chemistry, and in reality, large-scale preparations of even the simplest side-chain derivatives of many amino acids often become annoyingly strenuous due to the necessity of employing protecting groups, on one or more of the amino acid functionalities, during the synthetic sequence. However, in the case of hydroxyamino acids such as hydroxyproline, serine, threonine, tyrosine and 3,4-dihydroxyphenylalanine (DOPA, many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions renders possible chemoselective O-acylation, furnishing the corresponding side-chain esters directly, on multigram-scale, in a single step, and without chromatographic purification. Assuming a certain degree of stability under acidic reaction conditions, the method is also applicable for a number of related compounds, such as various amino alcohols and the thiol-functional amino acid cysteine. While the basic methodology underlying this approach has been known for decades, it has evolved through recent developments connected to amino acid-derived chiral organocatalysts to become a more widely recognized procedure for large-scale preparation of many useful side-chain derivatives of hydroxyamino acids and related compounds. Such derivatives are useful in peptide chemistry and drug development, as amino acid amphiphiles for asymmetric catalysis, and as amino acid acrylic precursors for preparation of

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Science.gov (United States)

2015-01-01

Summary Amino acids, whether natural, semisynthetic or synthetic, are among the most important and useful chiral building blocks available for organic chemical synthesis. In principle, they can function as inexpensive, chiral and densely functionalized starting materials. On the other hand, the use of amino acid starting materials routinely necessitates protective group chemistry, and in reality, large-scale preparations of even the simplest side-chain derivatives of many amino acids often become annoyingly strenuous due to the necessity of employing protecting groups, on one or more of the amino acid functionalities, during the synthetic sequence. However, in the case of hydroxyamino acids such as hydroxyproline, serine, threonine, tyrosine and 3,4-dihydroxyphenylalanine (DOPA), many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions renders possible chemoselective O-acylation, furnishing the corresponding side-chain esters directly, on multigram-scale, in a single step, and without chromatographic purification. Assuming a certain degree of stability under acidic reaction conditions, the method is also applicable for a number of related compounds, such as various amino alcohols and the thiol-functional amino acid cysteine. While the basic methodology underlying this approach has been known for decades, it has evolved through recent developments connected to amino acid-derived chiral organocatalysts to become a more widely recognized procedure for large-scale preparation of many useful side-chain derivatives of hydroxyamino acids and related compounds. Such derivatives are useful in peptide chemistry and drug development, as amino acid amphiphiles for asymmetric catalysis, and as amino acid acrylic precursors for preparation of

Expression of wild-type and mutant medium-chain acyl-CoA dehydrogenase (MCAD) cDNA in eucaryotic cells

DEFF Research Database (Denmark)

Jensen, T G; Andresen, B S; Bross, P

1992-01-01

An effective EBV-based expression system for eucaryotic cells has been developed and used for the study of the mitochondrial enzyme medium-chain acyl-CoA dehydrogenase (MCAD). 1325 bp of PCR-generated MCAD cDNA, containing the entire coding region, was placed between the SV40 early promoter...... and polyadenylation signals in the EBV-based vector. Both wild-type MCAD cDNA and cDNA containing the prevalent disease-causing mutation A to G at position 985 of the MCAD cDNA were tested. In transfected COS-7 cells, the steady state amount of mutant MCAD protein was consistently lower than the amount of wild......-type human enzyme. The enzyme activity in extracts from cells harbouring the wild-type MCAD cDNA was dramatically higher than in the controls (harbouring the vector without the MCAD gene) while only a slightly higher activity was measured with the mutant MCAD. The mutant MCAD present behaves like wild...

Generation of fatty acids by an acyl esterase in the bioluminescent system of Photobacterium phosphoreum

International Nuclear Information System (INIS)

Carey, L.M.; Rodriguez, A.; Meighen, E.

1984-01-01

The fatty acid reductase complex from Photobacterium phosphoreum has been discovered to have a long chain ester hydrolase activity associated with the 34K protein component of the complex. This protein has been resolved from the other components (50K and 58K) of the fatty acid reductase complex with a purity of > 95% and found to catalyze the transfer of acyl groups from acyl-CoA primarily to thiol acceptors with a low level of transfer to glycerol and water. Addition of the 50K protein of the complex caused a dramatic change in specificity increasing the transfer to oxygen acceptors. The acyl-CoA hydrolase activity increased almost 10-fold, and hence free fatty acids can be generated by the 34K protein when it is present in the fatty acid reductase complex. Hydrolysis of acyl-S-mercaptoethanol and acyl-1-glycerol and the ATP-dependent reduction of the released fatty acids to aldehyde for the luminescent reaction were also demonstrated for the reconstituted fatty acid reductase complex, raising the possibility that the immediate source of fatty acids for this reaction in vivo could be the membrane lipids and/or the fatty acid synthetase system

The hexanoyl-CoA precursor for cannabinoid biosynthesis is formed by an acyl-activating enzyme in Cannabis sativa trichomes.

Science.gov (United States)

Stout, Jake M; Boubakir, Zakia; Ambrose, Stephen J; Purves, Randy W; Page, Jonathan E

2012-08-01

The psychoactive and analgesic cannabinoids (e.g. Δ(9) -tetrahydrocannabinol (THC)) in Cannabis sativa are formed from the short-chain fatty acyl-coenzyme A (CoA) precursor hexanoyl-CoA. Cannabinoids are synthesized in glandular trichomes present mainly on female flowers. We quantified hexanoyl-CoA using LC-MS/MS and found levels of 15.5 pmol g(-1) fresh weight in female hemp flowers with lower amounts in leaves, stems and roots. This pattern parallels the accumulation of the end-product cannabinoid, cannabidiolic acid (CBDA). To search for the acyl-activating enzyme (AAE) that synthesizes hexanoyl-CoA from hexanoate, we analyzed the transcriptome of isolated glandular trichomes. We identified 11 unigenes that encoded putative AAEs including CsAAE1, which shows high transcript abundance in glandular trichomes. In vitro assays showed that recombinant CsAAE1 activates hexanoate and other short- and medium-chained fatty acids. This activity and the trichome-specific expression of CsAAE1 suggest that it is the hexanoyl-CoA synthetase that supplies the cannabinoid pathway. CsAAE3 encodes a peroxisomal enzyme that activates a variety of fatty acid substrates including hexanoate. Although phylogenetic analysis showed that CsAAE1 groups with peroxisomal AAEs, it lacked a peroxisome targeting sequence 1 (PTS1) and localized to the cytoplasm. We suggest that CsAAE1 may have been recruited to the cannabinoid pathway through the loss of its PTS1, thereby redirecting it to the cytoplasm. To probe the origin of hexanoate, we analyzed the trichome expressed sequence tag (EST) dataset for enzymes of fatty acid metabolism. The high abundance of transcripts that encode desaturases and a lipoxygenase suggests that hexanoate may be formed through a pathway that involves the oxygenation and breakdown of unsaturated fatty acids. © 2012 National Research Council of Canada. The Plant Journal © 2012 Blackwell Publishing Ltd.

Localization of acyl ghrelin- and des-acyl ghrelin-immunoreactive cells in the rat stomach and their responses to intragastric pH.

Science.gov (United States)

Mizutani, Makoto; Atsuchi, Kaori; Asakawa, Akihiro; Matsuda, Norifumi; Fujimura, Masaki; Inui, Akio; Kato, Ikuo; Fujimiya, Mineko

2009-11-01

Acyl ghrelin has a 28-amino acid sequence with O-n-octanoyl acid modification at the serine 3 position, whereas des-acyl ghrelin has no octanoyl acid modification. Although these peptides exert different physiological functions, no previous studies have shown the different localization of acyl ghrelin and des-acyl ghrelin in the stomach. Here we have developed an antibody specific for des-acyl ghrelin that does not crossreact with acyl ghrelin. Both acyl ghrelin- and des-acyl ghrelin-immunoreactive cells were distributed in the oxyntic and antral mucosa of the rat stomach, with higher density in the antral mucosa than oxyntic mucosa. Immunofluorescence double staining showed that acyl ghrelin- and des-acyl ghrelin-positive reactions overlapped in closed-type round cells, whereas des-acyl ghrelin-positive reaction was found in open-type cells in which acyl ghrelin was negative. Acyl ghrelin-/des-acyl ghrelin-positive closed-type cells contain obestatin; on the other hand, des-acyl ghrelin-positive open-type cells contain somatostatin. We measured the release of acyl ghrelin and des-acyl ghrelin in vascularly perfused rat stomach by ELISA, and the effects of different intragastric pH levels on the release of each peptide were examined. The release of des-acyl ghrelin from the perfused stomach was greater at pH 2 than at pH 4; however, the release of acyl ghrelin was not affected by intragastric pH. The present study demonstrated the differential localization of acyl ghrelin and des-acyl ghrelin in the rat stomach and their different responses to the intragastric pH.

ETFDH mutations as a major cause of riboflavin-responsive multiple acyl-CoA dehydrogenation deficiency

DEFF Research Database (Denmark)

Olsen, Rikke K J; Olpin, Simon E; Andresen, Brage S

2007-01-01

Multiple acyl-CoA dehydrogenation deficiency (MADD) is a disorder of fatty acid, amino acid and choline metabolism that can result from defects in two flavoproteins, electron transfer flavoprotein (ETF) or ETF: ubiquinone oxidoreductase (ETF:QO). Some patients respond to pharmacological doses......; several had previously suffered cyclical vomiting. Urine organic acid and plasma acyl-carnitine profiles indicated MADD. Clinical and biochemical parameters were either totally or partly corrected after riboflavin treatment. All patients had mutations in the gene for ETF:QO. In one patient, we show...... that the ETF:QO mutations are associated with a riboflavin-sensitive impairment of ETF:QO activity. This patient also had partial deficiencies of flavin-dependent acyl-CoA dehydrogenases and respiratory chain complexes, most of which were restored to control levels after riboflavin treatment. Low activities...

Recombinant expression, purification, and characterization of an acyl-CoA binding protein from Aspergillus oryzae.

Science.gov (United States)

Hao, Qing; Liu, Xiaoguang; Zhao, Guozhong; Jiang, Lu; Li, Ming; Zeng, Bin

2016-03-01

To characterize biochemically the lipid metabolism-regulating acyl-CoA binding protein (ACBP) from the industrially-important fungus Aspergillus oryzae. A full-length cDNA encoding a candidate ACBP from A. oryzae (AoACBP) was cloned and expressed in Escherichia coli as a maltose-binding protein (MBP) fusion protein. The MBP-AoACBP protein was purified by an amylose resin chromatography column. SDS-PAGE showed that MBP-AoACBP has an estimated molecular weight of 82 kDa. Microscale thermophoresis binding assay showed that the recombinant AoACBP displayed much greater affinity for palmitoyl-CoA (K d = 80 nM) than for myristoyl-CoA (K d = 510 nM), thus demonstrating the preference of AoACBP for long-chain acyl-CoA. The data support the identification of AoACBP as a long-chain ACBP in A. oryzae.

Folding of polymer chains with short-range binormal interactions

International Nuclear Information System (INIS)

Craig, A; Terentjev, E M

2006-01-01

We study the structure of chains which have anisotropic short-range contact interactions that depend on the alignment of the binormal vectors of chain segments. This represents a crude model of hydrogen bonding or 'stacking' interactions out of the plane of curvature. The polymers are treated as ribbon-like semi-flexible chains, where the plane of the ribbon is determined by the local binormal. We show that with dipole-dipole interactions between the binormals of contacting chain segments, mean-field theory predicts a first-order transition to a binormally aligned state. We describe the onset of this transition as a function of the temperature-dependent parameters that govern the chain stiffness and the strength of the binormal interaction, as well as the binormal alignment's coupling to chain collapse. We also examine a metastable state governing the folding kinetics. Finally, we discuss the possible mesoscopic structure of the aligned phase, and application of our model to secondary structure motifs like β-sheets and α-helices, as well as composite structures like β-(amyloid) fibrils

Contamination profiles of short-chain polychlorinated n-alkanes in foodstuff samples from Japan

Energy Technology Data Exchange (ETDEWEB)

Matsukami, Hidenori; Kurunthachalam, S; Ohi, Etsumasa; Takasuga, Takumi [Shimadzu Techno Research, Inc., Kyoto (Japan); Iino, Fukuya; Nakanishi, Junko [National Inst. of Advanced Industrial Science and Technology, Tsukuba (Japan)

2004-09-15

Polychlorinated n-alkanes (PCAs) are group of chemicals manufactured by chlorination of liquid n-paraffin or paraffin wax that contain 30 to 70% chlorine by weight. Large amounts of PCAs are widely used as plasticizers for vinyl chloride, lubricants, paints, and flame retardants and number of other industrial applications. Annual global production of PCAs is approximately 300 kilo tones, with a majority having medium-carbon-chain (C14-C19) length. According to the investigation made by Kagaku Kogyo Nippon-Sha, the annual consumption of PCAs in Japan was about 83,000 tons in between 1986-2001. Short-carbon-chain (C10-C13) has been placed on the Priority Substance List under Canadian Environmental Protection Act and on the Environmental Protection Agency Toxic Release Inventory in the USA due to its potential to act as tumor promoters in mammals. Data on environment levels of PCAs is meager, nevertheless, PCAs have been measured at relatively high concentrations in biota from Sweden, biota, sediment from Canada and marine biota and human milk from the Canadian Arctic. In our earlier study, we reported concentrations of short-chain PCAs from sewage treatment plant (STP) collected from Tama River, Tokyo and river water and sediment from Tokyo and Osaka. STP influent water contained greater shortchain PCAs concentrations than STP effluent. In addition, some river water and sediment samples contained detectable concentrations of short-chain PCAs, which was similar to other industrial countries. However, there is no study conducted to explore the contamination profiles of short-chain PCAs in human foodstuff samples. In the present study, we analyzed eleven foodstuff samples that were purchased from various supermarkets in order to know the short-chain PCAs concentrations in the foodstuff and possible human total daily intake (TDI) amounts.

Calculation of Physicochemical Properties for Short- and Medium-Chain Chlorinated Paraffins

Science.gov (United States)

Glüge, Juliane; Bogdal, Christian; Scheringer, Martin; Buser, Andreas M.; Hungerbühler, Konrad

2013-06-01

Short- and medium-chain chlorinated paraffins are potential PBT chemicals (persistent, bioaccumulative, toxic) and short-chain chlorinated paraffins are under review for inclusion in the UNEP Stockholm Convention on Persistent Organic Pollutants. Despite their high production volume of more than one million metric tonnes per year, only few data on their physicochemical properties are available. We calculated subcooled-liquid vapor pressure, subcooled-liquid solubility in water and octanol, Henry's law constant for water and octanol, as well as the octanol-water partition coefficient with the property calculation methods COSMOtherm, SPARC, and EPI Suite™, and compared the results to experimental data from the literature. For all properties, good or very good agreement between calculated and measured data was obtained for COSMOtherm; results from SPARC were in good agreement with the measured data except for subcooled-liquid water solubility, whereas EPI Suite™ showed the largest discrepancies for all properties. After critical evaluation of the three property calculation methods, a final set of recommended property data for short- and medium-chain chlorinated paraffins was derived. The calculated property data show interesting relationships with chlorine content and carbon chain length. Increasing chlorine content does not cause pronounced changes in water solubility and octanol-water partition coefficient (KOW) as long as it is below 55%. Increasing carbon chain length leads to strong increases in KOW and corresponding decreases in subcooled-liquid water solubility. The present data set can be used in further studies to assess the environmental fate and human exposure of this relevant compound class.

Vapor-liquid equilibrium and critical asymmetry of square well and short square well chain fluids.

Science.gov (United States)

Li, Liyan; Sun, Fangfang; Chen, Zhitong; Wang, Long; Cai, Jun

2014-08-07

The critical behavior of square well fluids with variable interaction ranges and of short square well chain fluids have been investigated by grand canonical ensemble Monte Carlo simulations. The critical temperatures and densities were estimated by a finite-size scaling analysis with the help of histogram reweighting technique. The vapor-liquid coexistence curve in the near-critical region was determined using hyper-parallel tempering Monte Carlo simulations. The simulation results for coexistence diameters show that the contribution of |t|(1-α) to the coexistence diameter dominates the singular behavior in all systems investigated. The contribution of |t|(2β) to the coexistence diameter is larger for the system with a smaller interaction range λ. While for short square well chain fluids, longer the chain length, larger the contribution of |t|(2β). The molecular configuration greatly influences the critical asymmetry: a short soft chain fluid shows weaker critical asymmetry than a stiff chain fluid with same chain length.

Linear rheology and structure of molecular bottlebrushes with short side chains

International Nuclear Information System (INIS)

López-Barrón, Carlos R.; Brant, Patrick; Crowther, Donna J.; Eberle, Aaron P. R.

2015-01-01

We investigate the microstructure and linear viscoelasticity of model molecular bottlebrushes (BBs) using rheological and small-angle X-ray and neutron scattering measurements. Our polymers have short atactic polypropylene (aPP) side chains of molecular weight ranging from 119 g/mol to 259 g/mol and narrow molecular weight distribution (M w /M n 1.02–1.05). The side chain molecular weights are a small fraction of the entanglement molecular weight of the corresponding linear polymer (M e,aPP = 7.05 kg/mol), and as such, they are unentangled. The morphology of the aPP BBs is characterized as semiflexible thick chains with small side chain interdigitation. Their dynamic master curves, obtained by time-temperature superposition, reveal two sequential relaxation processes corresponding to the segmental relaxation and the relaxation of the BB backbone. Due to the short length of the side chains, their fast relaxation could not be distinguished from the glassy relaxation. The fractional free volume is an increasing function of the side chain length (N SC ). Therefore, the glassy behavior of these polymers as well as their molecular friction and dynamic properties are influenced by their N SC values. The apparent flow activation energies are a decreasing function of N SC , and their values explain the differences in zero-shear viscosity measured at different temperatures

Effects of short-chain chlorinated paraffins on soil organisms.

Science.gov (United States)

Bezchlebová, Jitka; Cernohlávková, Jitka; Kobeticová, Klára; Lána, Jan; Sochová, Ivana; Hofman, Jakub

2007-06-01

Despite the fact that chlorinated paraffins have been produced in relatively large amounts, and high concentrations have been found in sewage sludge applied to soils, there is little information on their concentrations in soils and the effect on soil organisms. The aim of this study was to investigate the toxicity of chlorinated paraffins in soils. The effects of short-chain chlorinated paraffins (64% chlorine content) on invertebrates (Eisenia fetida, Folsomia candida, Enchytraeus albidus, Enchytraeus crypticus, Caenorhabditis elegans) and substrate-induced respiration of indigenous microorganisms were studied. Differences were found in the sensitivity of the tested organisms to short-chain chlorinated paraffins. F. candida was identified as the most sensitive organism with LC(50) and EC(50) values of 5733 and 1230 mg/kg, respectively. Toxicity results were compared with available studies and the predicted no effect concentration (PNEC) of 5.28 mg/kg was estimated for the soil environment, based on our data.

The most common mutation causing medium-chain acyl-CoA dehydrogenase deficiency is strongly associated with a particular haplotype in the region of the gene

DEFF Research Database (Denmark)

Kølvraa, S; Gregersen, N; Blakemore, A I

1991-01-01

RFLP haplotypes in the region containing the medium-chain acyl-CoA dehydrogenase (MCAD) gene on chromosome 1 have been determined in patients with MCAD deficiency. The RFLPs were detected after digestion of patient DNA with the enzymes BanII. PstI and TaqI and with an MCAD cDNA-clone as a probe....... Of 32 disease-causing alleles studied, 31 possessed the previously published A----G point-mutation at position 985 of the cDNA. This mutation has been shown to result in inactivity of the MCAD enzyme. In at least 30 of the 31 alleles carrying this G985 mutation a specific RFLP haplotype was present...

Adsorption of short-chain fluids at solid substrates from density functional theory

International Nuclear Information System (INIS)

Bryk, P.; Bucior, K.; Sokolowski, S.; Zukocinski, G.

2005-01-01

We use microscopic density functional theory to investigate the adsorption of short-chains at solid surfaces. The fluid is modeled as freely-jointed tangent spheres that interact via a short-ranged attractive potential. Within the framework of fundamental measure theory we study how the structure and surface phase behaviour of adsorbed fluid changes when the chain length is increased. We observe that the wetting temperature rescaled by the bulk critical temperature decreases with an increase of the chain length. For longer chains this temperature reaches a plateau. For the surface critical temperature an inverse effect is observed, i.e. the surface critical temperature increases with the chain length and then attains a plateau. Furthermore, we analyze how the layering transitions change with the change of the chain length and with relative strength of the fluid-solid interaction. The critical temperature of the first layering transition, rescaled by the bulk critical temperature increases slightly with an increase of the chain length. We have found that for longer chains the layering transitions within consecutive layers are shifted towards very low temperatures and that their sequence is finally replaced by a single transition. Finally we investigate capillary condensation of chain fluid in slit-like pores. We find that for a fluid of chains consisting of a larger number of segments we observe an inversion effect. Namely, the critical temperature of capillary condensation decreases with increasing pore width for a certain interval of values of the pore width. This anomalous behavior is also influenced by the interaction between molecules and pore walls. (author)

Lipase-catalyzed biodiesel synthesis with different acyl acceptors

Directory of Open Access Journals (Sweden)

Ognjanović Nevena D.

2008-01-01

Full Text Available Biodiesel is an alternative fuel for diesel engine that is environmentally acceptable. Conventionally, biodiesel is produced by transesterification of triglycerides and short alcohols in the presence of an acid or an alkaline catalyst. There are several problems associated with this kind of production that can be resolved by using lipase as the biocatalyst. The aim of the present work was to investigate novel acyl acceptors for biodiesel production. 2-Propanol and n-butanol have a less negative effect on lipase stability, and they also improve low temperature properties of the fuel. However, excess alcohol leads to inactivation of the enzyme, and glycerol, a major byproduct, can block the immobilized enzyme, resulting in low enzymatic activity. This problem was solved by using methyl acetate as acyl acceptor. Triacetylglycerol is produced instead of glycerol, and it has no negative effect on the activity of the lipase.

A Probabilistic Short-Term Water Demand Forecasting Model Based on the Markov Chain

Directory of Open Access Journals (Sweden)

Francesca Gagliardi

2017-07-01

Full Text Available This paper proposes a short-term water demand forecasting method based on the use of the Markov chain. This method provides estimates of future demands by calculating probabilities that the future demand value will fall within pre-assigned intervals covering the expected total variability. More specifically, two models based on homogeneous and non-homogeneous Markov chains were developed and presented. These models, together with two benchmark models (based on artificial neural network and naïve methods, were applied to three real-life case studies for the purpose of forecasting the respective water demands from 1 to 24 h ahead. The results obtained show that the model based on a homogeneous Markov chain provides more accurate short-term forecasts than the one based on a non-homogeneous Markov chain, which is in line with the artificial neural network model. Both Markov chain models enable probabilistic information regarding the stochastic demand forecast to be easily obtained.

An Efficient and Green Procedure for the Preparation of Acylals from ...

African Journals Online (AJOL)

An Efficient and Green Procedure for the Preparation of Acylals from Aldehydes Catalyzed by Alum [KAl(SO 4 ) 2 .12H 2 O] ... South African Journal of Chemistry ... mild reaction conditions, short reaction times and excellent yields, and offers a green synthetic solution by avoiding toxic catalysts and hazardous solvents.

Fluorescently labelled bovine acyl-CoA-binding protein acting as an acyl-CoA sensor: interaction with CoA and acyl-CoA esters and its use in measuring free acyl-CoA esters and non-esterified fatty acids

DEFF Research Database (Denmark)

Wadum, M.C.; Villadsen, J.K.; Feddersen, S.

2002-01-01

methods for the determination of free acyl-CoA concentrations. No such method is presently available. In the present study, we describe the synthesis of two acyl-CoA sensors for measuring free acyl-CoA concentrations using acyl-CoA-binding protein as a scaffold. Met24 and Ala53 of bovine acyl...... of ligand (excitation 387nm). Titration of FACI-24 and FACI-53 with hexadecanoyl-CoA and dodecanoyl-CoA increased the fluorescence yield 5.5-and 4.7-fold at 460 and 495nm respectively. FACI-24 exhibited a high, and similar increase in, fluorescence yield at 460nm upon binding of C14-C20 saturated...

Biocompatible choline based ionic salts: Solubility in short-chain alcohols

International Nuclear Information System (INIS)

Lopes, Joana M.; Paninho, Ana B.; Môlho, Marta F.; Nunes, Ana V.M.; Rocha, Angelo; Lourenço, Nuno M.T.; Najdanovic-Visak, Vesna

2013-01-01

Highlights: • Biocompatible ionic liquids based on choline esters were synthesized in this work. • Solubility of choline and choline esters based ionic salt in alcohols were measured. • Activity coefficients were calculated. • Experimental data were correlated by means of the semi-empirical Grant equation. -- Abstract: In this work, we report data on solubility of choline chloride and choline acetate in short-chain linear alcohols (ethanol, 1-propanol and 1-butanol) at various temperatures. Furthermore, we synthesize two choline derivatives: hydrogen choline chloride glutarate ([CholGlut][Cl]) and hydrogen choline chloride succinate ([CholSucc][Cl]). Their characterization and solubility in short-chain alcohols as a function of temperature are also included. Activity coefficients were calculated and their comparisons with ideal solutions were discussed. The experimental data were correlated successfully by means of the semi-empirical Grant equation

Structural aspects of pressure effects on infrared spectra of mixed-chain phosphatidylcholine assemblies in D2O

International Nuclear Information System (INIS)

Wong, P.T.; Huang, C.H.

1989-01-01

The barotropic behavior of D 2 O dispersions of 1-stearoyl-2-caproyl-sn-glycero-3-phosphocholine, C(18):C(10)PC, a highly asymmetric phospholipid in which the length of the fully extended acyl chain at the sn-1 position of the glycerol backbone is twice as long as that at the sn-2 position, has been investigated by high-pressure Fourier transform infrared spectroscopy. This asymmetric phosphatidylcholine bilayer at room temperature displays a pressure-induced phase transition corresponding to the liquid-crystalline----gel phase transition at 1.4 kbar. A conformational ordering of the lipid acyl chains is observed to take place abruptly at the transition pressure of 1.4 kbar. However, the lamellar lipid molecules and their acyl chains remain to be orientationally disordered in the gel phase until the applied pressure reaches 5.5 kbar. In the gel phase of fully hydrated C(18):C(10)PC, the asymmetric lipid molecules assemble into mixed interdigitated bilayers with perpendicular orientation of the zigzag planes among neighboring acyl chains. The role of excess water played in the interchain structure and the behavior of excess water and bound water under high pressure are also discussed

Risk assessment of Short and Medium Chain Chlorinated Paraffin’s (SCCP and MCCP)

DEFF Research Database (Denmark)

Christensen, Frans Møller; Olsen, Stig Irving

2002-01-01

findings of the Short Chain Chlorinated Paraffin (SCCP) and the draft Medium Chain Chlorinated Paraffin (MCCP) risk assessments. The political actions taken as a consequence of the assessments are also described. The risk assessments have been prepared according to the EU Technical Guidance Document (TGD...

Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis

Energy Technology Data Exchange (ETDEWEB)

Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

2016-11-04

Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys143) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ117) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation.

Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis.

Science.gov (United States)

Goblirsch, Brandon R; Jensen, Matthew R; Mohamed, Fatuma A; Wackett, Lawrence P; Wilmot, Carrie M

2016-12-23

Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety-unusual for a thiolase-are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys 143 ) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C 12 and C 14 ) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ 117 ) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis*

Science.gov (United States)

Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

2016-01-01

Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys143) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ117) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. PMID:27815501

Alkaline Ceramidase 3 (ACER3) Hydrolyzes Unsaturated Long-chain Ceramides, and Its Down-regulation Inhibits Both Cell Proliferation and Apoptosis*

OpenAIRE

Hu, Wei; Xu, Ruijuan; Sun, Wei; Szulc, Zdzislaw M.; Bielawski, Jacek; Obeid, Lina M.; Mao, Cungui

2010-01-01

Ceramides with different fatty acyl chains may vary in their physiological or pathological roles; however, it remains unclear how cellular levels of individual ceramide species are regulated. Here, we demonstrate that our previously cloned human alkaline ceramidase 3 (ACER3) specifically controls the hydrolysis of ceramides carrying unsaturated long acyl chains, unsaturated long-chain (ULC) ceramides. In vitro, ACER3 only hydrolyzed C18:1-, C20:1-, C20:4-ceramides, dihydroceramides, and phyto...

Effects of hematopoietic stem cell transplantation on acyl-CoA oxidase deficiency: a sibling comparison study

NARCIS (Netherlands)

Wang, Raymond Y.; Monuki, Edwin S.; Powers, James; Schwartz, Phillip H.; Watkins, Paul A.; Shi, Yang; Moser, Ann; Shrier, David A.; Waterham, Hans R.; Nugent, Diane J.; Abdenur, Jose E.

2014-01-01

Acyl-CoA oxidase (ACOX1) deficiency is a rare disorder of peroxisomal very-long chain fatty acid oxidation. No reports detailing attempted treatment, longitudinal imaging, or neuropathology exist. We describe the natural history of clinical symptoms and brain imaging in two siblings with ACOX1

Antibacterial and antifungal activities of new acylated derivatives of epigallocatechin gallate

Directory of Open Access Journals (Sweden)

Yoshimi eMatsumoto

2012-02-01

Full Text Available (--Epigallocatechin-3-O-gallate (EGCG has useful antiviral, antimicrobial, antitoxin, and antitumor properties. Previously, Mori, S. et al. (Bioorg Med Chem Lett 18:4249-4252, 2008 found that addition of long acyl chains (C16–18 to EGCG enhanced its anti-influenza virus activity up to 44-fold. The chemical stability of EGCG against oxidative degradation was also enhanced by acylation. We further evaluated the in vitro activity spectrum of the EGCG derivatives against a wide range of bacteria and fungi. A series of EGCG O-acyl derivatives were synthesized by lipase-catalyzed transesterification. These derivatives exhibited several-fold higher activities than EGCG, particularly against Gram-positive organisms. Antifungal activities of the derivatives were also 2 to 4-fold superior to those of EGCG. The activities of the EGCG derivatives against Gram-negative bacteria were not distinguishable from those of EGCG. Among the derivatives evaluated, MICs of dioctanoate, palmitate (C16, palmitoleate, and linolenate for 17 Staphylococcus aureus strains were 4–32 μg/ml, although MIC of EGCG for these 17 strains was >128 μg/ml. C16 demonstrated rapid bactericidal activity against MRSA at 25 μg/ml. The enhanced activity of C16 against S. aureus was supported by its increased membrane permeabilizing activity determined by increased SYTOX Green uptake. The EGCG derivatives were exported by the efflux pump AcrAB-TolC of Escherichia coli. The tolC deletion mutant exhibited higher sensitivity to C16 than to EGCG. Addition of long alkyl chains to EGCG significantly enhanced its activities against various bacteria and fungi, particularly against S. aureus including MRSA. C16 would be an alternative to antibiotics and disinfectants.

Friedel-Crafts Acylation with Amides

Science.gov (United States)

Raja, Erum K.; DeSchepper, Daniel J.; Nilsson Lill, Sten O.; Klumpp, Douglas A.

2012-01-01

Friedel-Crafts acylation has been known since the 1870s and it is an important organic synthetic reaction leading to aromatic ketone products. Friedel-Crafts acylation is usually done with carboxylic acid chlorides or anhydrides while amides are generally not useful substrates in these reactions. Despite being the least reactive carboxylic acid derivative, we have found a series of amides capable of providing aromatic ketones in good yields (55–96%, 17 examples). We propose a mechanism involving diminished C-N resonance through superelectrophilic activation and subsequent cleavage to acyl cations. PMID:22690740

Gut microbiota–derived short-chain fatty acids and kidney diseases

Directory of Open Access Journals (Sweden)

Li L

2017-12-01

Full Text Available Lingzhi Li, Liang Ma, Ping Fu Kidney Research Institute, Department of Nephrology, West China Hospital of Sichuan University, Chengdu 610041, China Abstract: Gut microbiota and its metabolites play pivotal roles in host physiology and pathology. Short-chain fatty acids (SCFAs, as a group of metabolites, exert positive regulatory effects on energy metabolism, hormone secretion, immune inflammation, hypertension, and cancer. The functions of SCFAs are related to their activation of transmembrane G protein-coupled receptors and their inhibition of histone acetylation. Though controversial, growing evidence suggests that SCFAs, which regulate inflammation, oxidative stress, and fibrosis, have been involved in kidney disease through the activation of the gut–kidney axis; however, the molecular relationship among gut microbiota–derived metabolites, signaling pathways, and kidney disease remains to be elucidated. This review will provide an overview of the physiology and functions of SCFAs in kidney disease. Keywords: gut microbiome, short-chain fatty acids, kidney diseases, gut–kidney axis

Determination of Short-Chain Chlorinated Paraffins by Carbon Skeleton Gas Chromatography

OpenAIRE

PELLIZZATO FRANCESCA; RICCI MARINA; HELD ANDREA; EMONS HENDRIK

2008-01-01

Short-Chain Chlorinated Paraffins (SCCPs) are highly complex technical mixtures of polychlorinated n-alkanes with a chlorination degree between 50 and 70 % by mass, and a linear carbon chain length from C10 to C13, constituted by thousands of homologues, diastereomers and enantiomers. They have been used in many different applications, such as extreme pressure additives in lubricants and cutting fluids, plasticizers in PVC, and flame retardants in paints, adhesives and sealants. SCCPs are tox...

Acyl-CoA-binding protein (ACBP) can mediate intermembrane acyl-CoA transport and donate acyl-CoA for beta-oxidation and glycerolipid synthesis

DEFF Research Database (Denmark)

Rasmussen, J T; Færgeman, Nils J.; Kristiansen, K

1994-01-01

The dissociation constants for octanoyl-CoA, dodecanoyl-CoA and hexadecanoyl-CoA binding to acyl-CoA-binding protein (ACBP) were determined by using titration microcalorimetry. The KD values obtained, (0.24 +/- 0.02) x 10(-6) M, (0.65 +/- 0.2) x 10(-8) M and (0.45 +/- 0.2) x 10(-13) M respectively......, were much lower than expected. ACBP was able to extract hexadecanoyl-CoA from phosphatidylcholine membranes immobilized on a nitrocellulose membrane. The acyl-CoA/ACBP complex formed was able to transport acyl-CoA to mitochondria or microsomes in suspension, or to microsomes immobilized...

Enhancement of Short Chain Fatty Acid Production from Millet Fibres ...

African Journals Online (AJOL)

Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. ... Methods: The effect of millet dietary fibre fermentation on production of short chain fatty ... fildes PYF enrichment solution was used as the .... where Pa is the peak area of SCFA, Ps is the ..... enzymatic- gravimetric method.

Alterations by peroxisome proliferators of acyl composition of hepatic phosphatidylcholine in rats, mice and guinea-pigs. Role of stearoyl-CoA desaturase.

Science.gov (United States)

Kawashima, Y; Hirose, A; Kozuka, H

1986-01-01

Rats, mice and guinea-pigs were administered p-chlorophenoxyisobutyric acid (clofibric acid) or 2,2'-(decamethylenedithio)diethanol (tiadenol). The treatments of rats and mice with either clofibric acid or tiadenol increased markedly the activities of stearoyl-CoA desaturase, palmitoyl-CoA chain elongation, 1-acylglycerophosphate (1-acyl-GP) acyltransferase and 1-acylglycerophosphocholine (1-acyl-GPC) acyltransferase, but not 2-acylglycerophosphocholine (2-acyl-GPC) acyltransferase in liver microsomes. The treatment of guinea-pigs with clofibric acid did not cause any change in the activities of these enzymes. The treatment of guinea-pigs with tiadenol caused a slight, but significant, increase in the activities of 1-acyl-GP acyltransferase and 1-acyl-GPC acyltransferase. The treatment of rats and mice with either clofibric acid or tiadenol increased markedly the proportion of 18:1 and decreased greatly the proportion of 18:0 in liver microsomal phosphatidylcholine. However, there is a considerable difference in the effects of the two peroxisome proliferators on the composition of polyunsaturated fatty acids in phosphatidylcholine between rats and mice. The treatment of guinea-pigs with either of the two peroxisome proliferators caused no change in acyl composition of phosphatidylcholine. The possible role of stearoyl-CoA desaturation in the regulation of acyl composition of phosphatidylcholine was discussed. PMID:2874791

Why is the sn-2 chain of monounsaturated glycerophospholipids usually unsaturated whereas the sn-1 chain is saturated? Studies of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (SOPC) and 1-oleoyl-2-stearoyl-sn-glycero-3-phosphatidylcholine (OSPC) membranes with and without cholesterol

DEFF Research Database (Denmark)

Martinez-Seara, Hector; Róg, Tomasz; Karttunen, Mikko

2009-01-01

Despite the large number of possible glycerol-based phospholipids, biological membranes contain only a small number of them. For example, double bonds in acyl chains are preferably located in the sn-2 chain. The question that emerges is: Why? We have addressed this question through atomistic simu....... The differences between the two isomers are enhanced when cholesterol is present as a result of the interaction of the off-plane cholesterol methyl groups with the double-bond carbon segments in the lipid acyl chains....

Characterization of a structurally and functionally diverged acyl-acyl carrier protein desaturase from milkweed seed.

Science.gov (United States)

Cahoon, E B; Coughlan, S J; Shanklin, J

1997-04-01

A cDNA for a structurally variant acyl-acyl carrier protein (ACP) desaturase was isolated from milkweed (Asclepias syriaca) seed, a tissue enriched in palmitoleic (16:1delta9)* and cis-vaccenic (18:1delta11) acids. Extracts of Escherichia coli that express the milkweed cDNA catalyzed delta9 desaturation of acyl-ACP substrates, and the recombinant enzyme exhibited seven- to ten-fold greater specificity for palmitoyl (16:0)-ACP and 30-fold greater specificity for myristoyl (14:0)-ACP than did known delta9-stearoyl (18:0)-ACP desaturases. Like other variant acyl-ACP desaturases reported to date, the milkweed enzyme contains fewer amino acids near its N-terminus compared to previously characterized delta9-18:0-ACP desaturases. Based on the activity of an N-terminal deletion mutant of a delta9-18:0-ACP desaturase, this structural feature likely does not account for differences in substrate specificities.

Physicochemical Parameters Affecting the Electrospray Ionization Efficiency of Amino Acids after Acylation

Science.gov (United States)

2017-01-01

Electrospray ionization (ESI) is widely used in liquid chromatography coupled to mass spectrometry (LC–MS) for the analysis of biomolecules. However, the ESI process is still not completely understood, and it is often a matter of trial and error to enhance ESI efficiency and, hence, the response of a given set of compounds. In this work we performed a systematic study of the ESI response of 14 amino acids that were acylated with organic acid anhydrides of increasing chain length and with poly(ethylene glycol) (PEG) changing certain physicochemical properties in a predictable manner. By comparing the ESI response of 70 derivatives, we found that there was a strong correlation between the calculated molecular volume and the ESI response, while correlation with hydrophobicity (log P values), pKa, and the inverse calculated surface tension was significantly lower although still present, especially for individual derivatized amino acids with increasing acyl chain lengths. Acylation with PEG containing five ethylene glycol units led to the largest gain in ESI response. This response was maximal independent of the calculated physicochemical properties or the type of amino acid. Since no actual physicochemical data is available for most derivatized compounds, the responses were also used as input for a quantitative structure–property relationship (QSPR) model to find the best physicochemical descriptors relating to the ESI response from molecular structures using the amino acids and their derivatives as a reference set. A topological descriptor related to molecular size (SPAN) was isolated next to a descriptor related to the atomic composition and structural groups (BIC0). The validity of the model was checked with a test set of 43 additional compounds that were unrelated to amino acids. While prediction was generally good (R2 > 0.9), compounds containing halogen atoms or nitro groups gave a lower predicted ESI response. PMID:28737384

Characterization of the mycobacterial acyl-CoA carboxylase holo complexes reveals their functional expansion into amino acid catabolism.

Directory of Open Access Journals (Sweden)

Matthias T Ehebauer

2015-02-01

Full Text Available Biotin-mediated carboxylation of short-chain fatty acid coenzyme A esters is a key step in lipid biosynthesis that is carried out by multienzyme complexes to extend fatty acids by one methylene group. Pathogenic mycobacteria have an unusually high redundancy of carboxyltransferase genes and biotin carboxylase genes, creating multiple combinations of protein/protein complexes of unknown overall composition and functional readout. By combining pull-down assays with mass spectrometry, we identified nine binary protein/protein interactions and four validated holo acyl-coenzyme A carboxylase complexes. We investigated one of these--the AccD1-AccA1 complex from Mycobacterium tuberculosis with hitherto unknown physiological function. Using genetics, metabolomics and biochemistry we found that this complex is involved in branched amino-acid catabolism with methylcrotonyl coenzyme A as the substrate. We then determined its overall architecture by electron microscopy and found it to be a four-layered dodecameric arrangement that matches the overall dimensions of a distantly related methylcrotonyl coenzyme A holo complex. Our data argue in favor of distinct structural requirements for biotin-mediated γ-carboxylation of α-β unsaturated acid esters and will advance the categorization of acyl-coenzyme A carboxylase complexes. Knowledge about the underlying structural/functional relationships will be crucial to make the target category amenable for future biomedical applications.

Pilot batch production of specific-structured lipids by lipase-catalyzed interesterification: preliminary study on incorporation and acyl migration

DEFF Research Database (Denmark)

Xu, Xuebing; Balchen, Steen; Høy, Carl-Erik

1998-01-01

Effects of water content, reaction time and their relationships in the production of two types of specific-structured lipids (sn-MLM- and sn-LML-types: L-long chain fatty acids; M-medium chain fatty acids) by lipase-catalyzed interesterification in a solvent-free system were studied...... of two totally position-opposed lipids can be observed. Presumably these are caused by the different chain length of the fatty acids. The relationships between reaction time and water content are inverse and give a quantitative prediction of incorporation and acyl migration in selected reaction...

Histone Deacetylase Inhibition and Dietary Short-Chain Fatty Acids

OpenAIRE

Licciardi, Paul V.; Ververis, Katherine; Karagiannis, Tom C.

2011-01-01

Changes in diet can also have dramatic effects on the composition of gut microbiota. Commensal bacteria of the gastrointestinal tract are critical regulators of health and disease by protecting against pathogen encounter whilst also maintaining immune tolerance to certain allergens. Moreover, consumption of fibre and vegetables typical of a non-Western diet generates substantial quantities of short-chain fatty acids (SCFAs) which have potent anti-inflammatory properties. Dietary interventions...

Label-free measurement of the yeast short chain TAG lipase activity by ESI-MS after one-step esterification.

Science.gov (United States)

Ham, Hye Jin; Seo, Jongcheol; Yoon, Hye-Joo; Shin, Seung Koo

2017-03-01

Triacylglycerol (TAG) lipases hydrolyze ester bonds in TAG and release diacylglycerol (DAG), monoacylglycerol (MAG), and FA. We present a one-step chemical derivatization method for label-free quantification of a mixture of TAG, DAG, and MAG following lipase assay by ESI-MS. Because the ionization efficiencies of TAG, DAG, and MAG are not identical, lipase reaction products, DAG and MAG, are derivatized to TAG species by esterifying their hydroxyl groups using acyl chloride, whose acyl chain contains one less (or one more) -CH 2 group than that of substrate TAG. This resulted in three TAG species that were separated by 14 Da from one another and exhibited similar ion responses representing their molar amounts in the mass spectra. A good linear correlation was observed between peak intensity ratios and molar ratios in calibration curve. This method enables simultaneous quantification of TAG, DAG, and MAG in lipase assay and, in turn, allows stoichiometric determination of the concentrations of FAs released from TAG and DAG separately. By applying this strategy to measure both TAG and DAG lipolytic activities of the yeast Tgl2 lipase, we demonstrated its usefulness in studying enzymatic catalysis, as lipase enzymes often show dissimilar activities toward these lipids. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Chemical probing of the human sirtuin 5 active site reveals its substrate acyl specificity and peptide-based inhibitors.

Science.gov (United States)

Roessler, Claudia; Nowak, Theresa; Pannek, Martin; Gertz, Melanie; Nguyen, Giang T T; Scharfe, Michael; Born, Ilona; Sippl, Wolfgang; Steegborn, Clemens; Schutkowski, Mike

2014-09-26

Sirtuins are NAD(+)-dependent deacetylases acting as sensors in metabolic pathways and stress response. In mammals there are seven isoforms. The mitochondrial sirtuin 5 is a weak deacetylase but a very efficient demalonylase and desuccinylase; however, its substrate acyl specificity has not been systematically analyzed. Herein, we investigated a carbamoyl phosphate synthetase 1 derived peptide substrate and modified the lysine side chain systematically to determine the acyl specificity of Sirt5. From that point we designed six potent peptide-based inhibitors that interact with the NAD(+) binding pocket. To characterize the interaction details causing the different substrate and inhibition properties we report several X-ray crystal structures of Sirt5 complexed with these peptides. Our results reveal the Sirt5 acyl selectivity and its molecular basis and enable the design of inhibitors for Sirt5. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Randomised clinical study: inulin short-chain fatty acid esters for targeted delivery of short-chain fatty acids to the human colon.

Science.gov (United States)

Polyviou, T; MacDougall, K; Chambers, E S; Viardot, A; Psichas, A; Jawaid, S; Harris, H C; Edwards, C A; Simpson, L; Murphy, K G; Zac-Varghese, S E K; Blundell, J E; Dhillo, W S; Bloom, S R; Frost, G S; Preston, T; Tedford, M C; Morrison, D J

2016-10-01

Short-chain fatty acids (SCFA) produced through fermentation of nondigestible carbohydrates by the gut microbiota are associated with positive metabolic effects. However, well-controlled trials are limited in humans. To develop a methodology to deliver SCFA directly to the colon, and to optimise colonic propionate delivery in humans, to determine its role in appetite regulation and food intake. Inulin SCFA esters were developed and tested as site-specific delivery vehicles for SCFA to the proximal colon. Inulin propionate esters containing 0-61 wt% (IPE-0-IPE-61) propionate were assessed in vitro using batch faecal fermentations. In a randomised, controlled, crossover study, with inulin as control, ad libitum food intake (kcal) was compared after 7 days on IPE-27 or IPE-54 (10 g/day all treatments). Propionate release was determined using (13) C-labelled IPE variants. In vitro, IPE-27-IPE-54 wt% propionate resulted in a sevenfold increase in propionate production compared with inulin (P inulin (439.5 vs. 703.9 kcal, P = 0.025) and IPE-54 (439.5 vs. 659.3 kcal, P = 0.025), whereas IPE-54 was not significantly different from inulin control. IPE-27 significantly reduced food intake suggesting colonic propionate plays a role in appetite regulation. Inulin short-chain fatty acid esters provide a novel tool for probing the diet-gut microbiome-host metabolism axis in humans. © 2016 The Authors. Alimentary Pharmacology & Therapeutics Published by John Wiley & Sons Ltd.

Age-dependent decline in acyl-ghrelin concentrations and reduced association of acyl-ghrelin and growth hormone in healthy older adults.

Science.gov (United States)

Nass, Ralf; Farhy, Leon S; Liu, Jianhua; Pezzoli, Suzan S; Johnson, Michael L; Gaylinn, Bruce D; Thorner, Michael O

2014-02-01

Acyl-ghrelin is thought to have both orexigenic effects and to stimulate GH release. A possible cause of the anorexia of aging is an age-dependent decrease in circulating acyl-ghrelin levels. The purpose of the study was to compare acyl-ghrelin and GH concentrations between healthy old and young adults and to examine the relationship of acyl-ghrelin and GH secretion in both age groups. Six healthy older adults (age 62-74 y, body mass index range 20.9-29 kg/m(2)) and eight healthy young men (aged 18-28 y, body mass index range 20.6-26.2 kg/m(2)) had frequent blood samples drawn for hormone measurements every 10 minutes for 24 hours. Ghrelin was measured in an in-house, two-site sandwich ELISA specific for full-length acyl-ghrelin. GH was measured in a sensitive assay (Immulite 2000), and GH peaks were determined by deconvolution analysis. The acyl-ghrelin/GH association was estimated from correlations between amplitudes of individual GH secretory events and the average acyl-ghrelin concentration in the 60-minute interval preceding each GH burst. Twenty-four-hour mean (±SEM) GH (0.48 ± 0.14 vs 2.2 ± 0.3 μg/L, P adults compared with young adults. Twenty-four-hour cortisol concentrations were higher in the old than the young adults (15.1 ± 1.0 vs 10.6 ± 0.9 μg/dL, respectively, P young adults (0.16 ± 0.12 vs 0.69 ± 0.04, P age-dependent decline in circulating acyl-ghrelin levels, which might play a role both in the decline of GH and in the anorexia of aging. Our data also suggest that with normal aging, endogenous acyl-ghrelin levels are less tightly linked to GH regulation.

Enzymatic production of biodiesel from microalgal oil using ethyl acetate as an acyl acceptor.

Science.gov (United States)

Alavijeh, Razieh Shafiee; Tabandeh, Fatemeh; Tavakoli, Omid; Karkhane, Aliasghar; Shariati, Parvin

2015-01-01

Microalgae have become an important source of biomass for biodiesel production. In enzymatic transesterification reaction, the enzyme activity is decreased in presence of alcohols. The use of different acyl acceptors such as methyl/ethyl acetate is suggested as an alternative and effective way to overcome this problem. In this study, ethyl acetate was used for the first time in the enzymatic production of biodiesel by using microalga, Chlorella vulgaris, as a triglyceride source. Enzymatic conversion of such fatty acids to biodiesel was catalyzed by Novozym 435 as an efficient immobilized lipase which is extensively used in biodiesel production. The best conversion yield of 66.71% was obtained at the ethyl acetate to oil molar ratio of 13:1 and Novozym 435 concentration of 40%, based on the amount of oil, and a time period of 72 h at 40℃. The results showed that ethyl acetate have no adverse effect on lipase activity and the biodiesel amount was not decreased even after seven transesterification cycles, so ethyl acetate has a great potential to be substituted for short-chain alcohols in transesterification reaction.

Lactobacillus rhamnosus GR-1 in Fermented Rice Pudding Supplemented with Short Chain Inulin, Long Chain Inulin, and Oat as a Novel Functional Food

Directory of Open Access Journals (Sweden)

Maja Williams

2017-10-01

Full Text Available Lactobacillus rhamnosus GR-1 is a probiotic that has been shown to reduce the risk of urogenital problems and urinary tract infections. Rice pudding is a popular gluten-free dairy product, and could be a vehicle to deliver L. rhamnosus GR-1 to a broader population. The purpose of this study was to investigate the growth and viability of L. rhamnosus GR-1 in six fermented rice pudding samples, each one supplemented with one type of prebiotic (short-chain inulin-2% w/w, 4% w/w; long-chain inulin-2% w/w, 4% w/w and oat-0.5% w/w, 1% w/w, along with control, over a 21-day storage period. The objective was to determine if the supplementation would have a positive effect on the microbial viability of L. rhamnosus GR-1, and to evaluate the sensory properties of the samples. All of the samples had viable levels of L. rhamnosus GR-1. Bacterial counts were at least 1 × 108 CFU/mL over the 21-day storage period. The probiotic rice pudding sample supplemented with 4% w/w short-chain inulin had the highest hedonic score for flavour, sweetness, texture, and overall acceptability. This study shows that the addition of short-chain inulin, long-chain inulin, and oat had no adverse supplementation effects on the viability of L. Rhamnosus GR-1. There is the potential for the production of a novel functional food.

Acylation of lithiated trimethylsilyl malonates and esters applied to the synthesis of molecules of biological interest, labelled with carbon 14

International Nuclear Information System (INIS)

Gorichon, Liliane

1978-01-01

This research thesis first reports an attempt to generalise the method of acylation of lithiated trimethylsilyl (TMS) malonates by introduction of new organic functions into the radical. This leads to the synthesis of some alkaloids such as nicotine and contine. The author also shows that fat acids can be labelled with carbon 14 in any position of the carbon chain. Thus, acylation of these malonates have been performed by using different acid chlorides. Then, the author reports attempts to simplify this method by using α-lithiated trimethylsilyl esters instead of malonates. He reports attempts of acylation of TMS isobutyrate, TMS proprionate and TMS acetate, by using different radioactive acid chlorides (benzoyl chloride, nicotinoyl chloride, lauryl chloride, and oleyl chloride). The author finally shows that both methods are equivalent by synthesising muscalure from TMS butylmalonate as well as from TMS hexanoate

Effects of rough handling on short chain fatty acid production and ...

African Journals Online (AJOL)

The influence of stress due to rough handling (RH) on gastrointestinal tract (GIT) environmental pH, concentration of short chain fatty acids (SCFAs) and modulatory roles of two Lactobacillus strains was investigated in broiler chickens. Equal number of chicks was randomly assigned to one of the following treatment groups; ...

Acylated flavone glycosides from Veronica

DEFF Research Database (Denmark)

Albach, Dirk C.; Grayer, Renée J.; Jensen, Søren Rosendal

2003-01-01

A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two rare allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from...

Endophytic Actinomycetes: A Novel Source of Potential Acyl Homoserine Lactone Degrading Enzymes

Directory of Open Access Journals (Sweden)

Surang Chankhamhaengdecha

2013-01-01

Full Text Available Several Gram-negative pathogenic bacteria employ N-acyl-L-homoserine lactone (HSL quorum sensing (QS system to control their virulence traits. Degradation of acyl-HSL signal molecules by quorum quenching enzyme (QQE results in a loss of pathogenicity in QS-dependent organisms. The QQE activity of actinomycetes in rhizospheric soil and inside plant tissue was explored in order to obtain novel strains with high HSL-degrading activity. Among 344 rhizospheric and 132 endophytic isolates, 127 (36.9% and 68 (51.5% of them, respectively, possessed the QQE activity. The highest HSL-degrading activity was at 151.30±3.1 nmole/h/mL from an endophytic actinomycetes isolate, LPC029. The isolate was identified as Streptomyces based on 16S  rRNA gene sequence similarity. The QQE from LPC029 revealed HSL-acylase activity that was able to cleave an amide bond of acyl-side chain in HSL substrate as determined by HPLC. LPC029 HSL-acylase showed broad substrate specificity from C6- to C12-HSL in which C10HSL is the most favorable substrate for this enzyme. In an in vitro pathogenicity assay, the partially purified HSL-acylase efficiently suppressed soft rot of potato caused by Pectobacterium carotovorum ssp. carotovorum as demonstrated. To our knowledge, this is the first report of HSL-acylase activity derived from an endophytic Streptomyces.

Microbial communities in methane- and short chain alkane-rich hydrothermal sediments of Guaymas Basin

Directory of Open Access Journals (Sweden)

Frederick eDowell

2016-01-01

Full Text Available The hydrothermal sediments of Guaymas Basin, an active spreading center in the Gulf of California (Mexico, are rich in porewater methane, short-chain alkanes, sulfate and sulfide, and provide a model system to explore habitat preferences of microorganisms, including sulfate-dependent, methane- and short chain alkane-oxidizing microbial communities. In this study, sediments (above 60˚C covered with sulfur-oxidizing microbial mats surrounding a hydrothermal mound (termed Mat Mound were characterized by porewater geochemistry of methane, C2-C6 short-chain alkanes, sulfate, sulfide, sulfate reduction rate measurements, in-situ temperature gradients, bacterial and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing. The most abundantly detected groups in the Mat mound sediments include anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister clade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within the Deltaproteobacteria and the separately branching HotSeep-1 Group; these uncultured bacteria are candidates for sulfate-reducing alkane oxidation and for sulfate-reducing syntrophy with ANME archaea. The archaeal dataset indicates distinct habitat preferences for ANME-1, ANME-1-Guaymas and ANME-2 archaea in Guaymas Basin hydrothermal sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath microbial mats in Guaymas Basin. We propose the working hypothesis that this mixed bacterial and archaeal community catalyzes the oxidation of both methane and short-chain alkanes, and constitutes a microbial community signature that is characteristic for hydrothermal and/or cold seep sediments containing both substrates.

Developments and interlaboratory study of the analysis of short-chain chlorinated paraffins

NARCIS (Netherlands)

van Mourik, L. M.; van der Veen, I.; Crum, S.; de Boer, J.

To survey the conformity and quality of the results between laboratories for short-chain chlorinated paraffins (SCCPs) determination, we reviewed current and novel analytical methods and organized four worldwide laboratory exercises between 2011 and 2017. Participants were requested to analyse test

Developments and interlaboratory study of the analysis of short-chain chlorinated paraffins

NARCIS (Netherlands)

Mourik, van L.M.; Veen, van der I.; Crum, S.; Boer, de J.

2018-01-01

To survey the conformity and quality of the results between laboratories for short-chain chlorinated paraffins (SCCPs) determination, we reviewed current and novel analytical methods and organized four worldwide laboratory exercises between 2011 and 2017. Participants were requested to analyse test

Branched-chain amino acid restriction in Zucker-fatty rats improves muscle insulin sensitivity by enhancing efficiency of fatty acid oxidation and acyl-glycine export.

Science.gov (United States)

White, Phillip J; Lapworth, Amanda L; An, Jie; Wang, Liping; McGarrah, Robert W; Stevens, Robert D; Ilkayeva, Olga; George, Tabitha; Muehlbauer, Michael J; Bain, James R; Trimmer, Jeff K; Brosnan, M Julia; Rolph, Timothy P; Newgard, Christopher B

2016-07-01

A branched-chain amino acid (BCAA)-related metabolic signature is strongly associated with insulin resistance and predictive of incident diabetes and intervention outcomes. To better understand the role that this metabolite cluster plays in obesity-related metabolic dysfunction, we studied the impact of BCAA restriction in a rodent model of obesity in which BCAA metabolism is perturbed in ways that mirror the human condition. Zucker-lean rats (ZLR) and Zucker-fatty rats (ZFR) were fed either a custom control, low fat (LF) diet, or an isonitrogenous, isocaloric LF diet in which all three BCAA (Leu, Ile, Val) were reduced by 45% (LF-RES). We performed comprehensive metabolic and physiologic profiling to characterize the effects of BCAA restriction on energy balance, insulin sensitivity, and glucose, lipid and amino acid metabolism. LF-fed ZFR had higher levels of circulating BCAA and lower levels of glycine compared to LF-fed ZLR. Feeding ZFR with the LF-RES diet lowered circulating BCAA to levels found in LF-fed ZLR. Activity of the rate limiting enzyme in the BCAA catabolic pathway, branched chain keto acid dehydrogenase (BCKDH), was lower in liver but higher in skeletal muscle of ZFR compared to ZLR and was not responsive to diet in either tissue. BCAA restriction had very little impact on metabolites studied in liver of ZFR where BCAA content was low, and BCKDH activity was suppressed. However, in skeletal muscle of LF-fed ZFR compared to LF-fed ZLR, where BCAA content and BCKDH activity were increased, accumulation of fatty acyl CoAs was completely normalized by dietary BCAA restriction. BCAA restriction also normalized skeletal muscle glycine content and increased urinary acetyl glycine excretion in ZFR. These effects were accompanied by lower RER and improved skeletal muscle insulin sensitivity in LF-RES fed ZFR as measured by hyperinsulinemic-isoglycemic clamp. Our data are consistent with a model wherein elevated circulating BCAA contribute to development of

Branched-chain amino acid restriction in Zucker-fatty rats improves muscle insulin sensitivity by enhancing efficiency of fatty acid oxidation and acyl-glycine export

Directory of Open Access Journals (Sweden)

Phillip J. White

2016-07-01

Full Text Available Objective: A branched-chain amino acid (BCAA-related metabolic signature is strongly associated with insulin resistance and predictive of incident diabetes and intervention outcomes. To better understand the role that this metabolite cluster plays in obesity-related metabolic dysfunction, we studied the impact of BCAA restriction in a rodent model of obesity in which BCAA metabolism is perturbed in ways that mirror the human condition. Methods: Zucker-lean rats (ZLR and Zucker-fatty rats (ZFR were fed either a custom control, low fat (LF diet, or an isonitrogenous, isocaloric LF diet in which all three BCAA (Leu, Ile, Val were reduced by 45% (LF-RES. We performed comprehensive metabolic and physiologic profiling to characterize the effects of BCAA restriction on energy balance, insulin sensitivity, and glucose, lipid and amino acid metabolism. Results: LF-fed ZFR had higher levels of circulating BCAA and lower levels of glycine compared to LF-fed ZLR. Feeding ZFR with the LF-RES diet lowered circulating BCAA to levels found in LF-fed ZLR. Activity of the rate limiting enzyme in the BCAA catabolic pathway, branched chain keto acid dehydrogenase (BCKDH, was lower in liver but higher in skeletal muscle of ZFR compared to ZLR and was not responsive to diet in either tissue. BCAA restriction had very little impact on metabolites studied in liver of ZFR where BCAA content was low, and BCKDH activity was suppressed. However, in skeletal muscle of LF-fed ZFR compared to LF-fed ZLR, where BCAA content and BCKDH activity were increased, accumulation of fatty acyl CoAs was completely normalized by dietary BCAA restriction. BCAA restriction also normalized skeletal muscle glycine content and increased urinary acetyl glycine excretion in ZFR. These effects were accompanied by lower RER and improved skeletal muscle insulin sensitivity in LF-RES fed ZFR as measured by hyperinsulinemic-isoglycemic clamp. Conclusions: Our data are consistent with a model wherein

Purification of a jojoba embryo fatty acyl-coenzyme A reductase and expression of its cDNA in high erucic acid rapeseed.

Science.gov (United States)

Metz, J G; Pollard, M R; Anderson, L; Hayes, T R; Lassner, M W

2000-03-01

The jojoba (Simmondsia chinensis) plant produces esters of long-chain alcohols and fatty acids (waxes) as a seed lipid energy reserve. This is in contrast to the triglycerides found in seeds of other plants. We purified an alcohol-forming fatty acyl-coenzyme A reductase (FAR) from developing embryos and cloned the cDNA encoding the enzyme. Expression of a cDNA in Escherichia coli confers FAR activity upon those cells and results in the accumulation of fatty alcohols. The FAR sequence shows significant homology to an Arabidopsis protein of unknown function that is essential for pollen development. When the jojoba FAR cDNA is expressed in embryos of Brassica napus, long-chain alcohols can be detected in transmethylated seed oils. Resynthesis of the gene to reduce its A plus T content resulted in increased levels of alcohol production. In addition to free alcohols, novel wax esters were detected in the transgenic seed oils. In vitro assays revealed that B. napus embryos have an endogenous fatty acyl-coenzyme A: fatty alcohol acyl-transferase activity that could account for this wax synthesis. Thus, introduction of a single cDNA into B. napus results in a redirection of a portion of seed oil synthesis from triglycerides to waxes.

Lipid membrane partitioning of lysolipids and fatty acids: Effects of membrane phase structure and detergent chain length

DEFF Research Database (Denmark)

Høyrup, Lise Pernille Kristine; Davidsen, Jesper; Jørgensen, Kent

2001-01-01

gel phase and at high temperatures in the disordered fluid phase of the phospholipid membrane vesicles. The long saturated acyl chains of the lysolipids and fatty acids varied from 10 to 16 carbon atoms and all titrations were performed below the critical micellar concentrations (cmc...... of magnitude higher when the saturated acyl chain of the detergents increases by two carbon atoms. The obtained partition coefficients are of importance in relation to a deeper understanding of the interplay between global aqueous and local membrane concentrations of the detergents and the functional influence...

Biosynthesis and function of simple amides in Xenorhabdus doucetiae.

Science.gov (United States)

Bode, Edna; He, Yue; Vo, Tien Duy; Schultz, Roland; Kaiser, Marcel; Bode, Helge B

2017-11-01

Xenorhabdus doucetiae, the bacterial symbiont of the entomopathogenic nematode Steinernema diaprepesi produces several different fatty acid amides. Their biosynthesis has been studied using a combination of analysis of gene deletions and promoter exchanges in X. doucetiae and heterologous expression of candidate genes in E. coli. While a decarboxylase is required for the formation of all observed phenylethylamides and tryptamides, the acyltransferase XrdE encoded in the xenorhabdin biosynthesis gene cluster is responsible for the formation of short chain acyl amides. Additionally, new, long-chain and cytotoxic acyl amides were identified in X. doucetiae infected insects and when X. doucetiae was grown in Galleria Instant Broth (GIB). When the bioactivity of selected amides was tested, a quorum sensing modulating activity was observed for the short chain acyl amides against the two different quorum sensing systems from Chromobacterium and Janthinobacterium. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Homozygosity for a severe novel medium-chain acyl-CoA dehydrogenase (MCAD) mutation IVS3-1G > C that leads to introduction of a premature termination codon by complete missplicing of the MCAD mRNA and is associated with phenotypic diversity ranging from sudden neonatal death to asymptomatic status

DEFF Research Database (Denmark)

Korman, Stanley H; Gutman, Alisa; Brooks, Rivka

2004-01-01

Virtually all patients with medium-chain acyl-CoA dehydrogenase deficiency (MCADD) are homozygous or compound heterozygous for the 985A > G mutation, which limits the study of a possible genotype/phenotype correlation. A newborn Palestinian infant died suddenly on the second day of life. A previo...

Anti-tumor effects of novel 5-O-acyl plumbagins based on the inhibition of mammalian DNA replicative polymerase activity.

Directory of Open Access Journals (Sweden)

Moe Kawamura

Full Text Available We previously found that vitamin K3 (menadione, 2-methyl-1,4-naphthoquinone inhibits the activity of human mitochondrial DNA polymerase γ (pol γ. In this study, we focused on plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone, and chemically synthesized novel plumbagins conjugated with C2:0 to C22:6 fatty acids (5-O-acyl plumbagins. These chemically modified plumbagins enhanced mammalian pol inhibition and their cytotoxic activity. Plumbagin conjugated with chains consisting of more than C18-unsaturated fatty acids strongly inhibited the activities of calf pol α and human pol γ. Plumbagin conjugated with oleic acid (C18:1-acyl plumbagin showed the strongest suppression of human colon carcinoma (HCT116 cell proliferation among the ten synthesized 5-O-acyl plumbagins. The inhibitory activity on pol α, a DNA replicative pol, by these compounds showed high correlation with their cancer cell proliferation suppressive activity. C18:1-Acyl plumbagin selectively inhibited the activities of mammalian pol species, but did not influence the activities of other pols and DNA metabolic enzymes tested. This compound inhibited the proliferation of various human cancer cell lines, and was the cytotoxic inhibitor showing strongest inhibition towards HT-29 colon cancer cells (LD50 = 2.9 µM among the nine cell lines tested. In an in vivo anti-tumor assay conducted on nude mice bearing solid tumors of HT-29 cells, C18:1-acyl plumbagin was shown to be a promising tumor suppressor. These data indicate that novel 5-O-acyl plumbagins act as anti-cancer agents based on mammalian DNA replicative pol α inhibition. Moreover, the results suggest that acylation of plumbagin is an effective chemical modification to improve the anti-cancer activity of vitamin K3 derivatives, such as plumbagin.

Elevated Medium-Chain Acylcarnitines Are Associated With Gestational Diabetes Mellitus and Early Progression to Type 2 Diabetes and Induce Pancreatic β-Cell Dysfunction.

Science.gov (United States)

Batchuluun, Battsetseg; Al Rijjal, Dana; Prentice, Kacey J; Eversley, Judith A; Burdett, Elena; Mohan, Haneesha; Bhattacharjee, Alpana; Gunderson, Erica P; Liu, Ying; Wheeler, Michael B

2018-05-01

Specific circulating metabolites have emerged as important risk factors for the development of diabetes. The acylcarnitines (acylCs) are a family of metabolites known to be elevated in type 2 diabetes (T2D) and linked to peripheral insulin resistance. However, the effect of acylCs on pancreatic β-cell function is not well understood. Here, we profiled circulating acylCs in two diabetes cohorts: 1 ) women with gestational diabetes mellitus (GDM) and 2 ) women with recent GDM who later developed impaired glucose tolerance (IGT), new-onset T2D, or returned to normoglycemia within a 2-year follow-up period. We observed a specific elevation in serum medium-chain (M)-acylCs, particularly hexanoyl- and octanoylcarnitine, among women with GDM and individuals with T2D without alteration in long-chain acylCs. Mice treated with M-acylCs exhibited glucose intolerance, attributed to impaired insulin secretion. Murine and human islets exposed to elevated levels of M-acylCs developed defects in glucose-stimulated insulin secretion and this was directly linked to reduced mitochondrial respiratory capacity and subsequent ability to couple glucose metabolism to insulin secretion. In conclusion, our study reveals that an elevation in circulating M-acylCs is associated with GDM and early stages of T2D onset and that this elevation directly impairs β-cell function. © 2018 by the American Diabetes Association.

Comparison of the orientational order of lipid chains in the Lα and HII phases

International Nuclear Information System (INIS)

Lafleur, M.; Cullis, P.R.; Fine, B.; Bloom, M.

1990-01-01

The orientational order profile has been determined by using deuterium nuclear magnetic resonance ( 2 H NMR) for POPE in the lamellar liquid-crystalline (L α ) and the hexagonal (H II ) phases and is shown to be sensitive to the symmetry of the lipid phase. In the H II phase, as compared to the L α phase, the acyl chains are characterized by a greater motional freedom, and the orientational order is distributed more uniformly along the lipid acyl chain. This is consistent with a change from a cylindrical to a wedge-shaped space available for the lipid chain. 2 H NMR studies of POPE dispersions containing tetradecanol or decane, both of which can induce H II phase structure, show very different behavior. Tetradecanol appears to align with the phospholipid chains and experience the L α to H II phase transition with a similar change in motional averaging as observed for the phospholipid chains themselves. In contrast, decane is apparently deeply embedded in the lipid structure and exhibits only a small degree of orientation. The L α to H II phase transition for systems containing decane leads to a dramatic increase of the motional freedom of decane which is more pronounced than that observed for the lipid chains. The presence of decane in the H II phase structure does not modify the order of the lipid chains. However, the L α phase of POPE is slightly disordered by the addition of 9 mol% decane whereas it can accommodate as much as 20 mol% tetradecanol without a significant change of order. Finally, the concept of a stretching vector associated with the lipid acyl chain has been introduced to analyze the orientational order profile obtained in the H II phase. With this model, the average order parameter of the H II phase has been calculated and found to be in good agreement with experiment

Analytische und Effektor-Studien von N-Acyl-Ethanolaminphosphaten

OpenAIRE

Ates, Ebru

2011-01-01

Bei N-Acyl-Ethanolaminphosphaten handelt es sich um eine bislang wenig untersuchte Klasse polarer Substanzen, deren Erforschung aufgrund ihrer strukturellen Analogie zu apolaren, physiologisch wirksamen N-Acyl-Ethanolaminen von Interesse ist. Zu bear-beiten waren analytische Fragestellungen, die auch synthetische Aufgaben beinhalteten, wie Methodenentwicklung und Versuche zur Erfassung von N-Acyl-Ethanolamin-phosphaten in ausgewählten Lebensmitteln sowie strukturelle Studien zur „Bioaktivität...

The Lipopolysaccharide Lipid A Long-Chain Fatty Acid Is Important for Rhizobium leguminosarum Growth and Stress Adaptation in Free-Living and Nodule Environments.

Science.gov (United States)

Bourassa, Dianna V; Kannenberg, Elmar L; Sherrier, D Janine; Buhr, R Jeffrey; Carlson, Russell W

2017-02-01

Rhizobium bacteria live in soil and plant environments, are capable of inducing symbiotic nodules on legumes, invade these nodules, and develop into bacteroids that fix atmospheric nitrogen into ammonia. Rhizobial lipopolysaccharide (LPS) is anchored in the bacterial outer membrane through a specialized lipid A containing a very long-chain fatty acid (VLCFA). VLCFA function for rhizobial growth in soil and plant environments is not well understood. Two genes, acpXL and lpxXL, encoding acyl carrier protein and acyltransferase, are among the six genes required for biosynthesis and transfer of VLCFA to lipid A. Rhizobium leguminosarum mutant strains acpXL, acpXL - /lpxXL - , and lpxXL - were examined for LPS structure, viability, and symbiosis. Mutations in acpXL and lpxXL abolished VLCFA attachment to lipid A. The acpXL mutant transferred a shorter acyl chain instead of VLCFA. Strains without lpxXL neither added VLCFA nor a shorter acyl chain. In all strains isolated from nodule bacteria, lipid A had longer acyl chains compared with laboratory-cultured bacteria, whereas mutant strains displayed altered membrane properties, modified cationic peptide sensitivity, and diminished levels of cyclic β-glucans. In pea nodules, mutant bacteroids were atypically formed and nitrogen fixation and senescence were affected. The role of VLCFA for rhizobial environmental fitness is discussed.

AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Science.gov (United States)

González, Alex; Bellenberg, Sören; Mamani, Sigde; Ruiz, Lina; Echeverría, Alex; Soulère, Laurent; Doutheau, Alain; Demergasso, Cecilia; Sand, Wolfgang; Queneau, Yves; Vera, Mario; Guiliani, Nicolas

2013-04-01

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type (AHLs). Our results revealed that AHL-signaling molecules with a long acyl chain (12 or 14 carbons) increased the adhesion of A. ferrooxidans cells to these substrates. In addition, Card-Fish experiments demonstrated that C14-AHL improved the adhesion of indigenous A. ferrooxidans cells from a mixed bioleaching community to pyrite. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances. Our results open up a promising means to develop new strategies for the improvement of bioleaching efficiency and metal recovery, which could also be used to control environmental damage caused by acid mine/rock drainage.

Xanthomonas campestris RpfB is a Fatty Acyl-CoA Ligase Required to Counteract the Thioesterase Activity of the RpfF Diffusible Signal Factor (DSF) Synthase

Science.gov (United States)

Bi, Hongkai; Yu, Yonghong; Dong, Huijuan; Wang, Haihong; Cronan, John E.

2014-01-01

SUMMARY In Xanthomonas campestris pv. campestris (Xcc), the proteins encoded by the rpf (regulator of pathogenicity factor) gene cluster produce and sense a fatty acid signal molecule called diffusible signaling factor (DSF, 2(Z)-11-methyldodecenoic acid). RpfB was reported to be involved in DSF processing and was predicted to encode an acyl-CoA ligase. We report that RpfB activates a wide range of fatty acids to their CoA esters in vitro. Moreover, RpfB can functionally replace the paradigm bacterial acyl-CoA ligase, Escherichia coli FadD, in the E. coli β-oxidation pathway and deletion of RpfB from the Xcc genome results in a strain unable to utilize fatty acids as carbon sources. An essential RpfB function in the pathogenicity factor pathway was demonstrated by the properties of a strain deleted for both the rpfB and rpfC genes. The ΔrpfB ΔrpfC strain grew poorly and lysed upon entering stationary phase. Deletion of rpfF, the gene encoding the DSF synthetic enzyme, restored normal growth to this strain. RpfF is a dual function enzyme that synthesizes DSF by dehydration of a 3-hydroxyacyl-acyl carrier protein (ACP) fatty acid synthetic intermediate and also cleaves the thioester bond linking DSF to ACP. However, the RpfF thioesterase activity is of broad specificity and upon elimination of its RpfC inhibitor RpfF attains maximal activity and its thioesterase activity proceeds to block membrane lipid synthesis by cleavage of acyl-ACP intermediates. This resulted in release of the nascent acyl chains to the medium as free fatty acids. This lack of acyl chains for phospholipid synthesis results in cell lysis unless RpfB is present to counteract the RpfF thioesterase activity by catalyzing uptake and activation of the free fatty acids to give acyl-CoAs that can be utilized to restore membrane lipid synthesis. Heterologous expression of a different fatty acid activating enzyme, the Vibrio harveyi acyl-ACP synthetase, replaced RpfB in counteracting the effects of

A Canonical Biotin Synthesis Enzyme, 8-Amino-7-Oxononanoate Synthase (BioF), Utilizes Different Acyl Chain Donors in Bacillus subtilis and Escherichia coli.

Science.gov (United States)

Manandhar, Miglena; Cronan, John E

2018-01-01

BioF (8-amino-7-oxononanoate synthase) is a strictly conserved enzyme that catalyzes the first step in assembly of the fused heterocyclic rings of biotin. The BioF acyl chain donor has long been thought to be pimeloyl-CoA. Indeed, in vitro the Escherichia coli and Bacillus sphaericus enzymes have been shown to condense pimeloyl-CoA with l-alanine in a pyridoxal 5'-phosphate-dependent reaction with concomitant CoA release and decarboxylation of l-alanine. However, recent in vivo studies of E. coli and Bacillus subtilis suggested that the BioF proteins of the two bacteria could have different specificities for pimelate thioesters in that E. coli BioF may utilize either pimeloyl coenzyme A (CoA) or the pimelate thioester of the acyl carrier protein (ACP) of fatty acid synthesis. In contrast, B. subtilis BioF seemed likely to be specific for pimeloyl-CoA and unable to utilize pimeloyl-ACP. We now report genetic and in vitro data demonstrating that B. subtilis BioF specifically utilizes pimeloyl-CoA. IMPORTANCE Biotin is an essential vitamin required by mammals and birds because, unlike bacteria, plants, and some fungi, these organisms cannot make biotin. Currently, the biotin included in vitamin tablets and animal feeds is made by chemical synthesis. This is partly because the biosynthetic pathways in bacteria are incompletely understood. This paper defines an enzyme of the Bacillus subtilis pathway and shows that it differs from that of Escherichia coli in the ability to utilize specific precursors. These bacteria have been used in biotin production and these data may aid in making biotin produced by biotechnology commercially competitive with that produced by chemical synthesis. Copyright © 2017 American Society for Microbiology.

An Efficient, Mild and Solvent-Free Synthesis of Benzene Ring Acylated Harmalines

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Sabira Begum

2009-12-01

Full Text Available A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, along with minor quantities of N-acyl-tryptamines and 8-acyl analogues of N-acyltryptamines.

Processing and fatty acid acylation of RAS1 and RAS2 proteins in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Fujiyama, A.; Tamanoi, F.

1986-01-01

The authors demonstrate the pathway for the biosynthesis of RAS1 and RAS2 gene products of Saccharomyces cerevisiae leading to their localization in membranes. The primary translation products of these genes are detected in a soluble fraction. Shortly after synthesis, these precursor molecules are converted to forms that migrate slightly faster than the precursor forms on a NaDodSO 4 /polyacrylamide gel. These processed proteins are further modified by fatty acid acylation, which is detected by [ 3 H]palmitic acid labeling. The acylated derivatives are found exclusively in cell membranes, indicating the translocation of the RAS proteins from cytosol to membranes during maturation process. The attached fatty acids can be released by mild alkaline hydrolysis, suggesting that the linkage between the fatty acid and the protein is an ester bond. The site of the modification by fatty acid is presumably localized to the COOH-terminal portion of the RAS proteins. Fraction of the membranes by sucrose gradient demonstrates that a majority of the fatty-acylated RAS proteins are localized in plasma membrane

Process development of short-chain polyols synthesis from corn stover by combination of enzymatic hydrolysis and catalytic hydrogenolysis

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Zhen-Hong Fang

2014-09-01

Full Text Available Currently short-chain polyols such as ethanediol, propanediol, and butanediol are produced either from the petroleum feedstock or from the starch-based food crop feedstock. In this study, a combinational process of enzymatic hydrolysis with catalytic hydrogenolysis for short-chain polyols production using corn stover as feedstock was developed. The enzymatic hydrolysis of the pretreated corn stover was optimized to produce stover sugars at the minimum cost. Then the stover sugars were purified and hydrogenolyzed into polyols products catalyzed by Raney nickel catalyst. The results show that the yield of short-chain polyols from the stover sugars was comparable to that of the corn-based glucose. The present study provided an important prototype for polyols production from lignocellulose to replace the petroleum- or corn-based polyols for future industrial applications.

Plasma levels of acylated ghrelin in patients with functional dyspepsia

Science.gov (United States)

Kim, Yeon Soo; Lee, Joon Seong; Lee, Tae Hee; Cho, Joo Young; Kim, Jin Oh; Kim, Wan Jung; Kim, Hyun Gun; Jeon, Seong Ran; Jeong, Hoe Su

2012-01-01

AIM: To investigate the relationship between plasma acylated ghrelin levels and the pathophysiology of functional dyspepsia. METHODS: Twenty-two female patients with functional dyspepsia and twelve healthy volunteers were recruited for the study. The functional dyspepsia patients were each diagnosed based on the Rome III criteria. Eligible patients completed a questionnaire concerning the severity of 10 symptoms. Plasma acylated ghrelin levels before and after a meal were determined in the study participants using a commercial human acylated enzyme immunoassay kit; electrogastrograms were performed for 50 min before and after a standardized 10-min meal containing 265 kcal. RESULTS: There were no significant differences in plasma acylated ghrelin levels between healthy volunteers and patients with functional dyspepsia. However, in patients with functional dyspepsia, there was a negative correlation between fasting plasma acylated ghrelin levels and the sum score of epigastric pain (r = -0.427, P = 0.047) and a positive correlation between the postprandial/fasting plasma acylated ghrelin ratio and the sum score of early satiety (r = 0.428, P =0.047). Additionally, there was a negative correlation between fasting acylated ghrelin plasma levels and fasting normogastria (%) (r = -0.522, P = 0.013). Interestingly, two functional dyspepsia patients showed paradoxically elevated plasma acylated ghrelin levels after the meal. CONCLUSION: Abnormal plasma acylated ghrelin levels before or after a meal may be related to several of the dyspeptic symptoms seen in patients with functional dyspepsia. PMID:22611317

Regulation of C. elegans fat uptake and storage by acyl-CoA synthase-3 is dependent on NR5A family nuclear hormone receptor nhr-25

DEFF Research Database (Denmark)

Mullaney, Brendan C; Blind, Raymond D; Lemieux, George A

2010-01-01

Acyl-CoA synthases are important for lipid synthesis and breakdown, generation of signaling molecules, and lipid modification of proteins, highlighting the challenge of understanding metabolic pathways within intact organisms. From a C. elegans mutagenesis screen, we found that loss of ACS-3...... mutant phenotypes require the nuclear hormone receptor NHR-25, a key regulator of C. elegans molting. Our findings suggest that ACS-3-derived long-chain fatty acyl-CoAs, perhaps incorporated into complex ligands such as phosphoinositides, modulate NHR-25 function, which in turn regulates an endocrine...... program of lipid uptake and synthesis. These results reveal a link between acyl-CoA synthase function and an NR5A family nuclear receptor in C. elegans....

Sex-related difference in the inductions by perfluoro-octanoic acid of peroxisomal beta-oxidation, microsomal 1-acylglycerophosphocholine acyltransferase and cytosolic long-chain acyl-CoA hydrolase in rat liver.

Science.gov (United States)

Kawashima, Y; Uy-Yu, N; Kozuka, H

1989-01-01

Inductions by perfluoro-octanoic acid (PFOA) of hepatomegaly, peroxisomal beta-oxidation, microsomal 1-acylglycerophosphocholine acyltransferase and cytosolic long-chain acyl-CoA hydrolase were compared in liver between male and female rats. Marked inductions of these four parameters were seen concurrently in liver of male rats, whereas the inductions in liver of female rats were far less pronounced. The sex-related difference in the response of rat liver to PFOA was much more marked than that seen with p-chlorophenoxyisobutyric acid (clofibric acid) or 2,2'-(decamethylenedithio)diethanol (tiadenol). Hormonal manipulations revealed that this sex-related difference in the inductions is strongly dependent on sex hormones, namely that testosterone is necessary for the inductions, whereas oestradiol prevented the inductions by PFOA. PMID:2570571

Geomicrobiological linkages between short-chain alkane consumption and sulfate reduction rates in seep sediments.

Directory of Open Access Journals (Sweden)

Arpita eBose

2013-12-01

Full Text Available Marine hydrocarbon seeps are ecosystems that are rich in methane, and, in some cases, short-chain (C2-C5 and longer alkanes. C2-C4 alkanes such as ethane, propane and butane can be significant components of seeping fluids. Some sulfate-reducing microbes oxidize short-chain alkanes anaerobically, and may play an important role in both the competition for sulfate and the local carbon budget. To better understand the anaerobic oxidation of short-chain n-alkanes coupled with sulfate-reduction, hydrocarbon-rich sediments from the Gulf of Mexico were amended with artificial, sulfate-replete seawater and one of four n-alkanes (C1-C4 then incubated under strict anaerobic conditions. Measured rates of alkane oxidation and sulfate reduction closely follow stoichiometric predictions that assume the complete oxidation of alkanes to CO2 (though other sinks for alkane carbon likely exist. Changes in the δ13C of all the alkanes in the reactors show enrichment over the course of the incubation, with the C3 and C4 incubations showing the greatest enrichment (4.4‰ and 4.5‰ respectively. The concurrent depletion in the δ13C of dissolved inorganic carbon (DIC implies a transfer of carbon from the alkane to the DIC pool (-3.5 and -6.7‰ for C3 and C4 incubations, respectively. Microbial community analyses reveal that certain members of the class Deltaproteobacteria are selectively enriched as the incubations degrade C1-C4 alkanes. Phylogenetic analyses indicate that distinct phylotypes are enriched in the ethane reactors, while phylotypes in the propane and butane reactors align with previously identified C3-C4 alkane-oxidizing sulfate-reducers. These data further constrain the potential influence of alkane oxidation on sulfate reduction rates in cold hydrocarbon-rich sediments, provide insight into their contribution to local carbon cycling, and illustrate the extent to which short-chain alkanes can serve as electron donors and govern microbial community

Isolation and amino acid sequence of a short-chain neurotoxin from an Australian elapid snake, Pseudechis australis.

OpenAIRE

Takasaki, C; Tamiya, N

1985-01-01

A short-chain neurotoxin Pseudechis australis a (toxin Pa a) was isolated from the venom of an Australian elapid snake Pseudechis australis (king brown snake) by sequential chromatography on CM-cellulose, Sephadex G-50 and CM-cellulose columns. Toxin Pa a has an LD50 (intravenous) value of 76 micrograms/kg body wt. in mice and consists of 62 amino acid residues. The amino acid sequence of Pa a shows considerable homology with those of short-chain neurotoxins of elapid snakes, especially of tr...

Deuterium-labelled N-acyl-l-homoserine lactones (AHLs) - inter-kingdom signalling molecules - synthesis, structural studies, and interactions with model lipid membranes

International Nuclear Information System (INIS)

Jakubczyk, Dorota; Barth, Christoph; Anastassacos, Frances; Koelsch, Patrick; Schepers, Ute; Kubas, Adam; Fink, Karin; Brenner-Weiss, Gerald; Braese, Stefan

2012-01-01

N-Acyl-l-homoserine lactones (AHLs) are synthesized by Gram-negative bacteria. These quorum-sensing molecules play an important role in the context of bacterial infection and biofilm formation. They also allow communication between microorganisms and eukaryotic cells (inter-kingdom signalling). However, very little is known about the entire mechanism of those interactions. Precise structural studies are required to analyse the different AHL isomers as only one form is biologically most active. Theoretical studies combined with experimental infrared and Raman spectroscopic data are therefore undertaken to characterise the obtained compounds. To mimic interactions between AHL and cell membranes, we studied the insertion of AHL in supported lipid bilayers, using vibrational sum-frequency-generation spectroscopy. Deuterium-labelled AHLs were thus synthesized. Starting from readily available deuterated fatty acids, a two-step procedure towards deuterated N-acyl-l-homoserine lactones with varying chain lengths is described. This included the acylation of Meldrum's acid followed by amidation. Additionally, the detailed analytical evaluation of the products is presented herein. (orig.)

Evaporation Kinetics in Short-Chain Alcohols by Optical Interference

Science.gov (United States)

Rosbrugh, Ian M.; Nishimura, S. Y.; Nishimura, A. M.

2000-08-01

The evaporation rates of volatile organic liquids may be determined through the observation of optical interference of spatially coincident light that is reflected from the top (air-liquid) and bottom (liquid-surface) of a liquid drop on a glass surface. As an example of what is possible with this technique, the evaporation for a series of short-chain alcohols and acetone was investigated. For 1-propanol, 2-propanol, 2-methyl-1-propanol, and acetone, the kinetics of evaporation was determined to be zero order. For methanol and ethanol, the process was significantly higher than zero order.

Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in Shanghai, China.

Science.gov (United States)

Li, Fei; Zhang, Chaojie; Qu, Yan; Chen, Jing; Chen, Ling; Liu, Ying; Zhou, Qi

2010-01-01

Perfluorinated acids (PFAs) have been recognized as emerging environmental pollutants because of their widespread occurrences, persistence, and bioaccumulative and toxicological effects. PFAs have been detected in aquatic environment and biota in China, but the occurrences of these chemicals have not been reported in solid matrices in China. In the present study, short- and long-chain PFAs (C2-C14) have been quantitatively determined in solid matrices including sediments, soils and sludge collected in Shanghai, China. The results indicate that sludge contains more PFAs than sediments and soils, and the total PFAs concentrations in sediments, soil and sludge are 62.5-276 ng g(-1), 141-237 ng g(-1) and 413-755 ng g(-1), respectively. In most cases, trifluoroacetic acid was the major PFA and accounted for 22-90% of the total PFAs. Although the levels of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) were not only lower than trifluoroacetic acid, but also lower than some short-chain PFCAs (PFAs, respectively. Meanwhile, unlike previous studies, PFOS levels were not always higher than PFOA in solids collected in Shanghai, China. Given that some short-chain PFAs such as trifluoroacetic acid are mildly phytotoxic and their higher levels in solid matrices were collected in Shanghai, China, these chemicals should be included in future environmental monitoring efforts.

A liver-specific defect of Acyl-CoA degradation produces hyperammonemia, hypoglycemia and a distinct hepatic Acyl-CoA pattern.

Directory of Open Access Journals (Sweden)

Nicolas Gauthier

Full Text Available Most conditions detected by expanded newborn screening result from deficiency of one of the enzymes that degrade acyl-coenzyme A (CoA esters in mitochondria. The role of acyl-CoAs in the pathophysiology of these disorders is poorly understood, in part because CoA esters are intracellular and samples are not generally available from human patients. We created a mouse model of one such condition, deficiency of 3-hydroxy-3-methylglutaryl-CoA lyase (HL, in liver (HLLKO mice. HL catalyses a reaction of ketone body synthesis and of leucine degradation. Chronic HL deficiency and acute crises each produced distinct abnormal liver acyl-CoA patterns, which would not be predictable from levels of urine organic acids and plasma acylcarnitines. In HLLKO hepatocytes, ketogenesis was undetectable. Carboxylation of [2-(14C] pyruvate diminished following incubation of HLLKO hepatocytes with the leucine metabolite 2-ketoisocaproate (KIC. HLLKO mice also had suppression of the normal hyperglycemic response to a systemic pyruvate load, a measure of gluconeogenesis. Hyperammonemia and hypoglycemia, cardinal features of many inborn errors of acyl-CoA metabolism, occurred spontaneously in some HLLKO mice and were inducible by administering KIC. KIC loading also increased levels of several leucine-related acyl-CoAs and reduced acetyl-CoA levels. Ultrastructurally, hepatocyte mitochondria of KIC-treated HLLKO mice show marked swelling. KIC-induced hyperammonemia improved following administration of carglumate (N-carbamyl-L-glutamic acid, which substitutes for the product of an acetyl-CoA-dependent reaction essential for urea cycle function, demonstrating an acyl-CoA-related mechanism for this complication.

Genetics Home Reference: short-chain acyl-CoA dehydrogenase deficiency

Science.gov (United States)

... An Y, Weavil SD, Chaing SH, Bali D, McDonald MT, Kishnani PS, Chen YT, Millington DS. Rare ... 10 All Bulletins Features What is direct-to-consumer genetic testing? What are genome editing and CRISPR- ...

The Bacillus subtilis Acyl Lipid Desaturase Is a Δ5 Desaturase

Science.gov (United States)

Altabe, Silvia G.; Aguilar, Pablo; Caballero, Gerardo M.; de Mendoza, Diego

2003-01-01

Bacillus subtilis was recently reported to synthesize unsaturated fatty acids (UFAs) with a double bond at positions Δ5, Δ7, and Δ9 (M. H. Weber, W. Klein, L. Muller, U. M. Niess, and M. A. Marahiel, Mol. Microbiol. 39:1321-1329, 2001). Since this finding would have considerable importance in the double-bond positional specificity displayed by the B. subtilis acyl lipid desaturase, we have attempted to confirm this observation. We report that the double bond of UFAs synthesized by B. subtilis is located exclusively at the Δ5 position, regardless of the growth temperature and the length chain of the fatty acids. PMID:12730185

Disparate effects of oxidation on plasma acyltransferase activities: inhibition of cholesterol esterification but stimulation of transesterification of oxidized phospholipids.

Science.gov (United States)

Subbaiah, P V; Liu, M

1996-05-31

Oxidation of lipoproteins results in the formation of several polar phospholipids with pro-inflammatory and pro-atherogenic properties. To examine the possible role of lecithin/cholesterol acyltransferase (LCAT) in the metabolism of these oxidized phospholipids, we oxidized whole plasma with either Cu(2+) or a free-radical generator, and determined the various activities of LCAT. Oxidation caused a reduction in plasma phosphatidylcholine (PC), an increase in a short-chain polar PC (SCP-PC), and an inhibition of the transfer of long-chain acyl groups to cholesterol (LCAT activity) or to lyso PC (lysolecithin acyltransferase (LAT) I activity). However, the transfer of short-chain acyl groups from SCP-PC to lyso PCLAT II activity) was stimulated several fold, in direct correlation with the degree of oxidation. LAT II activity was not stimulated by oxidation in LCAT-deficient plasma, showing that it is carried out by LCAT. Oxidized normal plasma exhibited low LCAT activity even in the presence of exogenous proteoliposome substrate, indicating that the depletion of substrate PC was not responsible for the loss of activity. Oxidation of isolated LDL or HDL abolished their ability to support LCAT and LAT I activities of exogenous enzyme, but promoted the LAT II activity. Purified LCAT lost its LCAT and LAT I functions, but not its LAT II function, when oxidized in vitro. These results show that while oxidation of plasma causes a loss of LCAT's ability to transfer long-chain acyl groups, its ability to transfer short-chain acyl groups, from SCP-PC is retained, and even stimulated, suggesting that LCAT may have a physiological role in the metabolism of oxidized PC in plasma.

Short-chain analogs of luteinizing hormone-releasing hormone containing cytotoxic moieties.

Science.gov (United States)

Janáky, T; Juhász, A; Rékási, Z; Serfözö, P; Pinski, J; Bokser, L; Srkalovic, G; Milovanovic, S; Redding, T W; Halmos, G

1992-11-01

Five hexapeptide and heptapeptide analogs of luteinizing hormone-releasing hormone (LH-RH) were synthesized for use as carriers for cytotoxic compounds. These short analogs were expected to enhance target selectivity of the antineoplastic agents linked to them. Native LH-RH-(3-9) and LH-RH-(4-9) containing D-lysine and D-ornithine at position 6 were amidated with ethylamine and acylated on the N terminus. The receptor-binding affinity of one hexapeptide carrier AJ-41 (Ac-Ser-Tyr-D-Lys-Leu-Arg-Pro-NH-Et) to human breast cancer cell membranes was similar to that of [D-Trp6]LH-RH. Alkylating nitrogen mustards (melphalan, Ac-melphalan), anthraquinone derivatives including anticancer antibiotic doxorubicin, antimetabolite (methotrexate), and cisplatin-like platinum complex were linked to these peptides through their omega-amino group at position 6. The hybrid molecules showed no LH-RH agonistic activity in vitro and in vivo but had nontypical antagonistic effects on pituitary cells in vitro at the doses tested. These analogs showed a wide range of receptor-binding affinities to rat pituitaries and cell membranes of human breast cancer and rat Dunning prostate cancer. Several of these conjugates exerted some cytotoxic effects on MCF-7 breast cancer cell line.

Antibiotic-associated diarrhoea, Clostridium difficile, and short-chain fatty acids

DEFF Research Database (Denmark)

Hove, H; Tvede, M; Mortensen, P B

1996-01-01

BACKGROUND: It has been hypothesized that Clostridium difficile and decreased colonic production of short-chain fatty acids (SCFAs) cause the development of antibiotic-associated diarrhoea. We therefore wanted to investigate the effects of an intensive and uniform antibiotic therapy on faecal SCFAs...... concentrations. C. difficile, and extent of diarrhoea. METHODS: Fifteen liver-transplanted patients who received oral bowel flora suppression therapy (6.3 g cefuroxime, 0.6 g tobramycin, and 0.5 g nystatin three times daily) were studied for 12 days before and 12 days after discontinuation of therapy. RESULTS...

[Contamination characteristics of short-chain chlorinated paraffins in edible fish of Shanghai].

Science.gov (United States)

Jiang, Guo; Chen, Lai-guo; He, Qiu-sheng; Meng, Xiang-zhou; Feng, Yong-bin; Huang, Yu-mei; Tang, Cai-ming

2013-09-01

According to the local habit of eating fish, in a total of 68 samples, 8 kinds of different trophic levels of edible fish collected in Shanghai were determined in terms of concentration and distribution profile of short chain chlorinated paraffin (SCCPs) in muscles to investigate the pollution status of SCCPs in edible fish from the Yangtze River Delta region. The results indicated that the concentrations (dw) of SCCPs in edible fish were in the range of 36-801 ng x g(-1). With the increase in carbon chain length, the concentration of SCCPs decreased. In addition, lower chlorinated (Cl6-Cl8) and shorter chain (Cl10, C11) congeners were the dominant chlorine and carbon homologues groups, respectively, contributing a total relative abundance of 61.46%-82.50% to the total abundance of SCCPs. The levels of SCCPs in fish of Shanghai were in the medium level worldwide, and the distribution pattern was in line with those of the domestic and foreign studies.

Rapid Hydrogen Shift Reactions in Acyl Peroxy Radicals

DEFF Research Database (Denmark)

Knap, Hasse Christian; Jørgensen, Solvejg

2017-01-01

-shift with X = 6, 7, 8, or 9) in the hydroperoxy acyl peroxy radicals, this H-shift is a reversible reaction and it scrambles between two peroxides, hydroperoxy acyl peroxy and peroxy peroxoic acid radicals. The forward reaction rate constants of the 1,X-OOH H-shift reactions are estimated to be above 103 s–1...... with transition state theory corrected with Eckart quantum tunnelling correction. The ratio between the forward and reverse reaction rate constant of the 1,X-OOH H-shift reactions is around ∼105. Therefore, the equilibrium is pushed toward the production of peroxy peroxoic acid radicals. These very fast 1,X-OOH H......We have used quantum mechanical chemical calculations (CCSD(T)-F12a/cc-pVDZ-F12//M06-2X/aug-cc-pVTZ) to investigate the hydrogen shift (H-shift) reactions in acyl peroxy and hydroperoxy acyl peroxy radicals. We have focused on the H-shift reactions from a hydroperoxy group (OOH) (1,X-OOH H...

Striving towards improved Friedel-Crafts acylation catalysts

International Nuclear Information System (INIS)

Scott, N.M.; Deacon, G.B.

1998-01-01

Full text: Lanthanum, ytterbium and scandium salts of trifluoromethanesulfonic acid have been shown to act as promising Lewis acid catalysts for the Friedel-Craft acylation reactions. In our study catalytic acylation of anisole by acetic anhydride in nitroethane was investigated. Yields were determined after extraction of para-methoxyacetophenone from the reaction mixture by G.L.C using the external standardisation method. Anhydrous lanthanoid tris-triflate salts [Ln(O 3 SCF 3 ) 3 , Ln La, Y, Nd, Eu and Yb] were initially investigated as catalysts. Ytterbium tris-triflate was found to be the most effective giving ∼90% of the acylation product. The hydrated lanthanide tris-nitrate salts [Ln(NO 3 ) 3 .nH 2 O, Ln = La, Nd, Eu and Yb] were also investigated using in situ dehydration with acetic anhydride. These were found to have low solubility in the reaction mixture and gave poor yields of para-methoxyacetophenone. The formation of side products was suggested by the low total recovery of anisole and para-methoxyacetophenone. The blocking of coordination sites of these catalysts by tetraglyme resulted in a 50% reduction in acylation activity compared with the simple salt. Addition of Li(O 3 SCF 3 ) to Ln(O 3 SCF 3 ) 3 catalysts (ratio of 4:1)had only a slight accelerating effect on the Friedel-Crafts acylation reaction and the yield was only marginally greater than that in the absence of the added salt. In contrast Li(ClO 4 ) dramatically decreased reaction times and improved the yield of para-methoxyace-tophenone, as recently reported

Short-chain alkanes fuel mussel and sponge Cycloclasticus symbionts from deep-sea gas and oil seeps.

Science.gov (United States)

Rubin-Blum, Maxim; Antony, Chakkiath Paul; Borowski, Christian; Sayavedra, Lizbeth; Pape, Thomas; Sahling, Heiko; Bohrmann, Gerhard; Kleiner, Manuel; Redmond, Molly C; Valentine, David L; Dubilier, Nicole

2017-06-19

Cycloclasticus bacteria are ubiquitous in oil-rich regions of the ocean and are known for their ability to degrade polycyclic aromatic hydrocarbons (PAHs). In this study, we describe Cycloclasticus that have established a symbiosis with Bathymodiolus heckerae mussels and poecilosclerid sponges from asphalt-rich, deep-sea oil seeps at Campeche Knolls in the southern Gulf of Mexico. Genomic and transcriptomic analyses revealed that, in contrast to all previously known Cycloclasticus, the symbiotic Cycloclasticus appears to lack the genes needed for PAH degradation. Instead, these symbionts use propane and other short-chain alkanes such as ethane and butane as carbon and energy sources, thus expanding the limited range of substrates known to power chemosynthetic symbioses. Analyses of short-chain alkanes in the environment of the Campeche Knolls symbioses revealed that these are present at high concentrations (in the μM to mM range). Comparative genomic analyses revealed high similarities between the genes used by the symbiotic Cycloclasticus to degrade short-chain alkanes and those of free-living Cycloclasticus that bloomed during the Deepwater Horizon oil spill. Our results indicate that the metabolic versatility of bacteria within the Cycloclasticus clade is higher than previously assumed, and highlight the expanded role of these keystone species in the degradation of marine hydrocarbons.

Detecting and characterizing N-acyl-homoserine lactone signal molecules by thin-layer chromatography

Science.gov (United States)

Shaw, Paul D.; Ping, Gao; Daly, Sean L.; Cha, Chung; Cronan, John E.; Rinehart, Kenneth L.; Farrand, Stephen K.

1997-01-01

Many Gram-negative bacteria regulate gene expression in response to their population size by sensing the level of acyl-homoserine lactone signal molecules which they produce and liberate to the environment. We have developed an assay for these signals that couples separation by thin-layer chromatography with detection using Agrobacterium tumefaciens harboring lacZ fused to a gene that is regulated by autoinduction. With the exception of N-butanoyl-l-homoserine lactone, the reporter detected acyl-homoserine lactones with 3-oxo-, 3-hydroxy-, and 3-unsubstituted side chains of all lengths tested. The intensity of the response was proportional to the amount of the signal molecule chromatographed. Each of the 3-oxo- and the 3-unsubstituted derivatives migrated with a unique mobility. Using the assay, we showed that some bacteria produce as many as five detectable signal molecules. Structures could be assigned tentatively on the basis of mobility and spot shape. The dominant species produced by Pseudomonas syringae pv. tabaci chromatographed with the properties of N-(3-oxohexanoyl)-l-homoserine lactone, a structure that was confirmed by mass spectrometry. An isolate of Pseudomonas fluorescens produced five detectable species, three of which had novel chromatographic properties. These were identified as the 3-hydroxy- forms of N-hexanoyl-, N-octanoyl-, and N-decanoyl-l-homoserine lactone. The assay can be used to screen cultures of bacteria for acyl-homoserine lactones, for quantifying the amounts of these molecules produced, and as an analytical and preparative aid in determining the structures of these signal molecules. PMID:9177164

Caveolar fatty acids and acylation of caveolin-1.

Directory of Open Access Journals (Sweden)

Qian Cai

Full Text Available Caveolae are cholesterol and sphingolipids rich subcellular domains on plasma membrane. Caveolae contain a variety of signaling proteins which provide platforms for signaling transduction. In addition to enriched with cholesterol and sphingolipids, caveolae also contain a variety of fatty acids. It has been well-established that acylation of protein plays a pivotal role in subcellular location including targeting to caveolae. However, the fatty acid compositions of caveolae and the type of acylation of caveolar proteins remain largely unknown. In this study, we investigated the fatty acids in caveolae and caveolin-1 bound fatty acids.Caveolae were isolated from Chinese hamster ovary (CHO cells. The caveolar fatty acids were extracted with Folch reagent, methyl esterificated with BF3, and analyzed by gas chromatograph-mass spectrometer (GC/MS. The caveolin-1 bound fatty acids were immunoprecipitated by anti-caveolin-1 IgG and analyzed with GC/MS.In contrast to the whole CHO cell lysate which contained a variety of fatty acids, caveolae mainly contained three types of fatty acids, 0.48 µg palmitic acid, 0.61 µg stearic acid and 0.83 µg oleic acid/caveolae preparation/5 × 10(7 cells. Unexpectedly, GC/MS analysis indicated that caveolin-1 was not acylated by myristic acid; instead, it was acylated by palmitic acid and stearic acid.Caveolae contained a special set of fatty acids, highly enriched with saturated fatty acids, and caveolin-1 was acylated by palmitic acid and stearic acid. The unique fatty acid compositions of caveolae and acylation of caveolin-1 may be important for caveolae formation and for maintaining the function of caveolae.

Barriers to the development of the short supply chain for local food producers in Romania

Directory of Open Access Journals (Sweden)

Lavinia DOVLEAC

2017-07-01

Full Text Available This article highlights the importance of short food supply chains for the development of rural areas in Romania, considering the increasing demand of the population for healthy food. A proper functionality of these local food supply chains brings benefits to producers, consumers and the local community, but some issues must be solved. This article presents the results of a qualitative marketing research study conducted for identifying the difficulties in this sector. The study aimed to identify the small producers’ opinions on the barriers to the development of these supply chains and how they could be helped to sell their products at a fair price.

Changes in short-chain fatty acid plasma profile incurred by dietary fiber composition

DEFF Research Database (Denmark)

Knudsen, Knud Erik Bach; Jørgensen, Henry Johs. Høgh; Theil, Peter Kappel

2016-01-01

Pigs were used as model for humans to study the impact of dietary fiber (DF), the main substrate for microbial fermentation, on plasma profile of short-chain fatty acids (SCFA; acetate, propionate, and butyrate). Six female pigs fitted with catheters in the portal vein and mesenteric artery and w...... higher net absorption of butyrate (2.4–4.0 vs. 1.6 mmol/h; P ...Pigs were used as model for humans to study the impact of dietary fiber (DF), the main substrate for microbial fermentation, on plasma profile of short-chain fatty acids (SCFA; acetate, propionate, and butyrate). Six female pigs fitted with catheters in the portal vein and mesenteric artery...... >> arabinoxylan >> β-glucan, whereas in the WWG, WAF, and RAF, diets it was arabinoxylan >> cellulose > β-glucan. The diets were fed to the pigs during 3 wk in a crossover design. Within an experimental week, WFL was supplied on Days 1 through 3 and WWG, WAF, or RAF was supplied during Days 4 through 7. Fasting...

Deuterium-labelled N-acyl-l-homoserine lactones (AHLs) - inter-kingdom signalling molecules - synthesis, structural studies, and interactions with model lipid membranes

Energy Technology Data Exchange (ETDEWEB)

Jakubczyk, Dorota [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Barth, Christoph; Anastassacos, Frances; Koelsch, Patrick; Schepers, Ute [Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Kubas, Adam; Fink, Karin [Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Brenner-Weiss, Gerald [Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Braese, Stefan [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany)

2012-04-15

N-Acyl-l-homoserine lactones (AHLs) are synthesized by Gram-negative bacteria. These quorum-sensing molecules play an important role in the context of bacterial infection and biofilm formation. They also allow communication between microorganisms and eukaryotic cells (inter-kingdom signalling). However, very little is known about the entire mechanism of those interactions. Precise structural studies are required to analyse the different AHL isomers as only one form is biologically most active. Theoretical studies combined with experimental infrared and Raman spectroscopic data are therefore undertaken to characterise the obtained compounds. To mimic interactions between AHL and cell membranes, we studied the insertion of AHL in supported lipid bilayers, using vibrational sum-frequency-generation spectroscopy. Deuterium-labelled AHLs were thus synthesized. Starting from readily available deuterated fatty acids, a two-step procedure towards deuterated N-acyl-l-homoserine lactones with varying chain lengths is described. This included the acylation of Meldrum's acid followed by amidation. Additionally, the detailed analytical evaluation of the products is presented herein. (orig.)

Glycogen with short average chain length enhances bacterial durability

Science.gov (United States)

Wang, Liang; Wise, Michael J.

2011-09-01

Glycogen is conventionally viewed as an energy reserve that can be rapidly mobilized for ATP production in higher organisms. However, several studies have noted that glycogen with short average chain length in some bacteria is degraded very slowly. In addition, slow utilization of glycogen is correlated with bacterial viability, that is, the slower the glycogen breakdown rate, the longer the bacterial survival time in the external environment under starvation conditions. We call that a durable energy storage mechanism (DESM). In this review, evidence from microbiology, biochemistry, and molecular biology will be assembled to support the hypothesis of glycogen as a durable energy storage compound. One method for testing the DESM hypothesis is proposed.

Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic.

Science.gov (United States)

Pribylová, Petra; Klánová, Jana; Holoubek, Ivan

2006-11-01

Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ngg(-1) for short-chain chlorinated paraffins, and 5575 ngg(-1) for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%.

Binding of the human "electron transferring flavoprotein" (ETF) to the medium chain acyl-CoA dehydrogenase (MCAD) involves an arginine and histidine residue.

Science.gov (United States)

Parker, Antony R

2003-10-01

The interaction between the "electron transferring flavoprotein" (ETF) and medium chain acyl-CoA dehydrogenase (MCAD) enables successful flavin to flavin electron transfer, crucial for the beta-oxidation of fatty acids. The exact biochemical determinants for ETF binding to MCAD are unknown. Here we show that binding of human ETF, to MCAD, was inhibited by 2,3-butanedione and diethylpyrocarbonate (DEPC) and reversed by incubation with free arginine and hydroxylamine respectively. Spectral analyses of native ETF vs modified ETF suggested that flavin binding was not affected and that the loss of ETF activity with MCAD involved modification of one ETF arginine residue and one ETF histidine residue respectively. MCAD and octanoyl-CoA protected ETF against inactivation by both 2,3-butanedione and DEPC indicating that the arginine and histidine residues are present in or around the MCAD binding site. Comparison of exposed arginine and histidine residues among different ETF species, however, indicates that arginine residues are highly conserved but that histidine residues are not. These results lead us to conclude that this single arginine residue is essential for the binding of ETF to MCAD, but that the single histidine residue, although involved, is not.

Sudden unexpected infant death (SUDI in a newborn due to medium chain acyl CoA dehydrogenase (MCAD deficiency with an unusual severe genotype

Directory of Open Access Journals (Sweden)

Lovera Cristina

2012-10-01

Full Text Available Abstract Medium chain acyl CoA dehydrogenase deficiency (MCAD is the most common inborn error of fatty acid oxidation. This condition may lead to cellular energy shortage and cause severe clinical events such as hypoketotic hypoglycemia, Reye syndrome and sudden death. MCAD deficiency usually presents around three to six months of life, following catabolic stress as intercurrent infections or prolonged fasting, whilst neonatal-onset of the disease is quite rare. We report the case of an apparently healthy newborn who suddenly died at the third day of life, in which the diagnosis of MCAD deficiency was possible through peri-mortem blood-spot acylcarnitine analysis that showed very high concentrations of octanoylcarnitine. Genetic analysis at the ACADM locus confirmed the biochemical findings by demonstrating the presence in homozygosity of the frame-shift c.244dup1 (p.Trp82LeufsX23 mutation, a severe genotype that may explain the unusual and very early fatal outcome in this newborn. This report confirms that inborn errors of fatty acid oxidation represent one of the genetic causes of sudden unexpected deaths in infancy (SUDI and underlines the importance to include systematically specific metabolic screening in any neonatal unexpected death.

Gut-derived short-chain fatty acids are vividly assimilated into host carbohydrates and lipids

NARCIS (Netherlands)

den Besten, Gijs; Lange, Katja; Havinga, Rick; van Dijk, Theo H.; Gerding, Albert; van Eunen, Karen; Muller, Michael; Groen, Albert K.; Hooiveld, Guido J.; Bakker, Barbara M.; Reijngoud, Dirk-Jan

2013-01-01

Acetate, propionate, and butyrate are the main short-chain fatty acids (SCFAs) that arise from the fermentation of fibers by the colonic microbiota. While many studies focus on the regulatory role of SCFAs, their quantitative role as a catabolic or anabolic substrate for the host has received

Conformational explosion: Understanding the complexity of short chain para-dialkylbenzene potential energy surfaces

Science.gov (United States)

Mishra, Piyush; Hewett, Daniel M.; Zwier, Timothy S.

2018-05-01

The single-conformation ultraviolet and infrared spectroscopy of three short-chain para-dialkylbenzenes (para-diethylbenzene, para-dipropylbenzene, and para-dibutylbenzene) is reported for the jet-cooled, isolated molecules. The present study builds off previous work on single-chain n-alkylbenzenes, where an anharmonic local mode Hamiltonian method was developed to account for stretch-bend Fermi resonance in the alkyl CH stretch region [D. P. Tabor et al., J. Chem. Phys. 144, 224310 (2016)]. The jet-cooled molecules are interrogated using laser-induced fluorescence (LIF) excitation, fluorescence dip infrared spectroscopy, and dispersed fluorescence. The LIF spectra in the S1 ← S0 origin region show a dramatic increase in the number of resolved transitions with increasing length of the alkyl chains, reflecting an explosion in the number of unique low-energy conformations formed when two independent alkyl chains are present. Since the barriers to isomerization of the alkyl chain are similar in size, this results in an "egg carton" shaped potential energy surface. A combination of electronic frequency shift and alkyl CH stretch infrared spectra is used to generate a consistent set of conformational assignments. Using these experimental techniques in conjunction with computational methods, subsets of origin transitions in the LIF excitation spectrum can be classified into different conformational families. Two conformations are resolved in para-diethylbenzene, seven in para-dipropylbenzene, and about nineteen in para-dibutylbenzene. These chains are largely independent of each other as there are no new single-chain conformations induced by the presence of a second chain. A cursory LIF excitation scan of para-dioctylbenzene shows a broad congested spectrum at frequencies consistent with interactions of alkyl chains with the phenyl π cloud.

Regioselective Acylation of Diols and Triols: The Cyanide Effect.

Science.gov (United States)

Peng, Peng; Linseis, Michael; Winter, Rainer F; Schmidt, Richard R

2016-05-11

Central topics of carbohydrate chemistry embrace structural modifications of carbohydrates and oligosaccharide synthesis. Both require regioselectively protected building blocks that are mainly available via indirect multistep procedures. Hence, direct protection methods targeting a specific hydroxy group are demanded. Dual hydrogen bonding will eventually differentiate between differently positioned hydroxy groups. As cyanide is capable of various kinds of hydrogen bonding and as it is a quite strong sterically nondemanding base, regioselective O-acylations should be possible at low temperatures even at sterically congested positions, thus permitting formation and also isolation of the kinetic product. Indeed, 1,2-cis-diols, having an equatorial and an axial hydroxy group, benzoyl cyanide or acetyl cyanide as an acylating agent, and DMAP as a catalyst yield at -78 °C the thermodynamically unfavorable axial O-acylation product; acyl migration is not observed under these conditions. This phenomenon was substantiated with 3,4-O-unproteced galacto- and fucopyranosides and 2,3-O-unprotected mannopyranosides. Even for 3,4,6-O-unprotected galactopyranosides as triols, axial 4-O-acylation is appreciably faster than O-acylation of the primary 6-hydroxy group. The importance of hydrogen bonding for this unusual regioselectivity could be confirmed by NMR studies and DFT calculations, which indicate favorable hydrogen bonding of cyanide to the most acidic axial hydroxy group supported by hydrogen bonding of the equatorial hydroxy group to the axial oxygen. Thus, the "cyanide effect" is due to dual hydrogen bonding of the axial hydroxy group which enhances the nucleophilicity of the respective oxygen atom, permitting an even faster reaction for diols than for mono-ols. In contrast, fluoride as a counterion favors dual hydrogen bonding to both hydroxy groups leading to equatorial O-acylation.

Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in Shanghai, China

International Nuclear Information System (INIS)

Li, Fei; Zhang, Chaojie; Qu, Yan; Chen, Jing; Chen, Ling; Liu, Ying; Zhou, Qi

2010-01-01

Perfluorinated acids (PFAs) have been recognized as emerging environmental pollutants because of their widespread occurrences, persistence, and bioaccumulative and toxicological effects. PFAs have been detected in aquatic environment and biota in China, but the occurrences of these chemicals have not been reported in solid matrices in China. In the present study, short- and long-chain PFAs (C2-C14) have been quantitatively determined in solid matrices including sediments, soils and sludge collected in Shanghai, China. The results indicate that sludge contains more PFAs than sediments and soils, and the total PFAs concentrations in sediments, soil and sludge are 62.5-276 ng g -1 , 141-237 ng g -1 and 413-755 ng g -1 , respectively. In most cases, trifluoroacetic acid was the major PFA and accounted for 22-90% of the total PFAs. Although the levels of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) were not only lower than trifluoroacetic acid, but also lower than some short-chain PFCAs (< C8) in some individual cases, PFOA and PFOS were still the major pollution compounds in most cases and they constituted 2-34% and 1-9% of the total PFAs, respectively. Meanwhile, unlike previous studies, PFOS levels were not always higher than PFOA in solids collected in Shanghai, China. Given that some short-chain PFAs such as trifluoroacetic acid are mildly phytotoxic and their higher levels in solid matrices were collected in Shanghai, China, these chemicals should be included in future environmental monitoring efforts.

Dechlorination of short chain chlorinated paraffins by nanoscale zero-valent iron.

Science.gov (United States)

Zhang, Zhi-Yong; Lu, Mang; Zhang, Zhong-Zhi; Xiao, Meng; Zhang, Min

2012-12-01

In this study, nanoscale zero-valent iron (NZVI) particles were synthesized and used for the reductive dehalogenation of short chain chlorinated paraffins (SCCPs) in the laboratory. The results show that the dechlorination rate of chlorinated n-decane (CP(10)) by NZVI increased with decreased solution pH. Increasing the loading of NZVI enhanced the dechlorination rate of CP(10). With an increase in temperature, the degradation rate increased. The reduction of CP(10) by NZVI was accelerated with increasing the concentration of humic acid up to 15 mg/L but then was inhibited. The dechlorination of CP(10) within the initial 18 h followed pseudo-first order rate model. The formation of intermediate products indicates a stepwise dechlorination pathway of SCCPs by NZVI. The carbon chain length and chlorination degree of SCCPs have a polynominal impact on dechlorination reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

Colonic infusions of short-chain fatty acid mixtures promote energy metabolism in overweight/obese men

DEFF Research Database (Denmark)

Canfora, Emanuel E; van der Beek, Christina M; Jocken, Johan W E

2017-01-01

Short-chain fatty acids (SCFA), formed by microbial fermentation, are believed to be involved in the aetiology of obesity and diabetes. This study investigated the effects of colonic administration of physiologically relevant SCFA mixtures on human substrate and energy metabolism...

The Impact of Short-Sale Constraints on Asset Allocation Strategies via the Backward Markov Chain Approximation Method

OpenAIRE

Carl Chiarella; Chih-Ying Hsiao

2005-01-01

This paper considers an asset allocation strategy over a finite period under investment uncertainty and short-sale constraints as a continuous time stochastic control problem. Investment uncertainty is characterised by a stochastic interest rate and inflation risk. If there are no short-sale constraints, the optimal asset allocation strategy can be solved analytically. We consider several kinds of short-sale constraints and employ the backward Markov chain approximation method to explore the ...

Divorcing folding from function: how acylation affects the membrane-perturbing properties of an antimicrobial peptide

DEFF Research Database (Denmark)

Vad, Brian Stougaard; Thomsen, Line Aagot Hede; Bertelsen, Kresten

2010-01-01

Many small cationic peptides, which are unstructured in aqueous solution, have antimicrobial properties. These properties are assumed to be linked to their ability to permeabilize bacterial membranes, accompanied by the transition to an alpha-helical folding state. Here we show that there is no d......Many small cationic peptides, which are unstructured in aqueous solution, have antimicrobial properties. These properties are assumed to be linked to their ability to permeabilize bacterial membranes, accompanied by the transition to an alpha-helical folding state. Here we show...... that there is no direct link between folding of the antimicrobial peptide Novicidin (Nc) and its membrane permeabilization. N-terminal acylation with C8-C16 alkyl chains and the inclusion of anionic lipids both increase Nc's ability to form alpha-helical structure in the presence of vesicles. Nevertheless, both acylation......, this cannot rationalize our results since permeabilization and antimicrobial activities are observed well below concentrations where aggregation occurs. This suggests that significant induction of alpha-helical structure is not a prerequisite for membrane perturbation in this class of antimicrobial peptides...

Central and peripheral des-acyl ghrelin regulates body temperature in rats.

Science.gov (United States)

Inoue, Yoshiyuki; Nakahara, Keiko; Maruyama, Keisuke; Suzuki, Yoshiharu; Hayashi, Yujiro; Kangawa, Kenji; Murakami, Noboru

2013-01-04

In the present study using rats, we demonstrated that central and peripheral administration of des-acyl ghrelin induced a decrease in the surface temperature of the back, and an increase in the surface temperature of the tail, although the effect of peripheral administration was less marked than that of central administration. Furthermore, these effects of centrally administered des-acyl ghrelin could not be prevented by pretreatment with [D-Lys3]-GHRP-6 GH secretagogue receptor 1a (GHS-R1a) antagonists. Moreover, these actions of des-acyl ghrelin on body temperature were inhibited by the parasympathetic nerve blocker methylscopolamine but not by the sympathetic nerve blocker timolol. Using immunohistochemistry, we confirmed that des-acyl ghrelin induced an increase of cFos expression in the median preoptic nucleus (MnPO). Additionally, we found that des-acyl ghrelin dilated the aorta and tail artery in vitro. These results indicate that centrally administered des-acyl ghrelin regulates body temperature via the parasympathetic nervous system by activating neurons in the MnPO through interactions with a specific receptor distinct from the GHS-R1a, and that peripherally administered des-acyl ghrelin acts on the central nervous system by passing through the blood-brain barrier, whereas it exerts a direct action on the peripheral vascular system. Copyright © 2012 Elsevier Inc. All rights reserved.

Reprogramming Acyl Carrier Protein Interactions of an Acyl-CoA Promiscuous trans-Acyltransferase

DEFF Research Database (Denmark)

Ye, Zhixia; Musiol-Kroll, Ewa Maria; Weber, Tilmann

2014-01-01

Protein interactions between acyl carrier proteins (ACPs) and trans-acting acyltransferase domains (trans-ATs) are critical for regioselective extender unit installation by many polyketide synthases, yet little is known regarding the specificity of these interactions, particularly for trans-ATs w...

Acyl-CoA binding protein and epidermal barrier function

DEFF Research Database (Denmark)

Bloksgaard, Maria; Neess, Ditte; Færgeman, Nils J

2014-01-01

The acyl-CoA binding protein (ACBP) is a 10kDa intracellular protein expressed in all eukaryotic species and mammalian tissues investigated. It binds acyl-CoA esters with high specificity and affinity and is thought to act as an intracellular transporter of acyl-CoA esters between different...... includes tousled and greasy fur, development of alopecia and scaling of the skin with age. Furthermore, epidermal barrier function is compromised causing a ~50% increase in transepidermal water loss relative to that of wild type mice. Lipidomic analyses indicate that this is due to significantly reduced...

Short-term droughts forecast using Markov chain model in Victoria, Australia

Science.gov (United States)

Rahmat, Siti Nazahiyah; Jayasuriya, Niranjali; Bhuiyan, Muhammed A.

2017-07-01

A comprehensive risk management strategy for dealing with drought should include both short-term and long-term planning. The objective of this paper is to present an early warning method to forecast drought using the Standardised Precipitation Index (SPI) and a non-homogeneous Markov chain model. A model such as this is useful for short-term planning. The developed method has been used to forecast droughts at a number of meteorological monitoring stations that have been regionalised into six (6) homogenous clusters with similar drought characteristics based on SPI. The non-homogeneous Markov chain model was used to estimate drought probabilities and drought predictions up to 3 months ahead. The drought severity classes defined using the SPI were computed at a 12-month time scale. The drought probabilities and the predictions were computed for six clusters that depict similar drought characteristics in Victoria, Australia. Overall, the drought severity class predicted was quite similar for all the clusters, with the non-drought class probabilities ranging from 49 to 57 %. For all clusters, the near normal class had a probability of occurrence varying from 27 to 38 %. For the more moderate and severe classes, the probabilities ranged from 2 to 13 % and 3 to 1 %, respectively. The developed model predicted drought situations 1 month ahead reasonably well. However, 2 and 3 months ahead predictions should be used with caution until the models are developed further.

Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride

International Nuclear Information System (INIS)

Li, Conghu; Tian, Zhenhua; Liu, Wentao; Li, Guoying

2015-01-01

The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen. - Highlights: • Acylated collagen retained the unique triple helix conformation. • Acylated collagen had stronger thermostability than native collagen. • Amide I was the most sensitive band to the temperature for acylated collagen. • Amide II was the most sensitive band to the temperature for native collagen. • Auto-peak at 1680 cm −1 for acylated collagen disappeared at higher temperature

Carbapenems and SHV-1 β-Lactamase Form Different Acyl-Enzyme Populations in Crystals and Solution

Science.gov (United States)

Kalp, Matthew; Carey, Paul R.

2009-01-01

The reactions between single crystals of the SHV-1 β-lactamase enzyme and the carbapenems, meropenem, imipenem and ertapenem, have been studied by Raman microscopy. Aided by quantum mechanical calculations, major populations of two acyl-enzyme species, a labile Δ2-pyrroline and a more tightly bound Δ1-pyrroline, have been identified for all three compounds. These isomers differ only in the position of the double bond about the carbapenem nucleus. This discovery is consonant with X-ray crystallographic findings that also identified two populations for meropenem bound in SHV-1: one with the acyl C=O group in the oxyanion hole and the second with the acyl group rotated 180 degrees compared to its expected position [Nukaga, M., Bethel, C. R., Thomson, J. M., Hujer, A. M., Distler, A. M., Anderson, V. E., Knox, J. R., and Bonomo, R. A. (2008) Journal of the American Chemical Society]. When crystals of the Δ1 and Δ2 containing acyl-enzymes were exposed to solutions with no carbapenem, rapid deacylation of the Δ2 species was observed by kinetic Raman experiments. However, no change in the Δ1 population was observed over 1 hour, the effective lifetime of the crystal. These observations lead to the hypothesis that the stable Δ1 species is due to the form seen by X-ray with the acyl carbonyl outside the oxyanion hole, while the Δ2 species corresponds to the form with the carbonyl inside the oxyanion hole. Soak-in and soak-out Raman experiments also demonstrated that tautomeric exchange between the Δ1 and Δ2 forms does not occur on the crystalline enzyme. When meropenem or ertapenem were reacted with SHV-1 in solution, the Raman difference spectra demonstrated that only a major population corresponding to the Δ1 acyl-enzyme could be detected. The 1003 cm-1 mode of the phenyl ring positioned on the C3 side chain of ertapenem acts as an effective internal Raman intensity standard and the ratio of its intensity to that of the 1600 cm-1 feature of Δ1 provides an

Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic

International Nuclear Information System (INIS)

Pribylova, Petra; Klanova, Jana; Holoubek, Ivan

2006-01-01

Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ng g -1 for short-chain chlorinated paraffins, and 5575 ng g -1 for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%. - Data on contamination of sediments from industrial areas fill the informational gap in the field of contamination of the Central Europe by chlorinated paraffins

A Novel Protocol to Analyze Short- and Long-Chain Fatty Acids Using Nonaqueous Microchip Capillary Electrophoresis

Science.gov (United States)

Cable, M. L.; Stockton, A. M.; Mora, Maria F; Willis, P. A.

2013-01-01

We propose a new protocol to identify and quantify both short- and long-chain saturated fatty acids in samples of astrobiological interest using non-aqueous microchip capillary electrophoresis (micronNACE) with laser induced fluorescence (LIF).

Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical Isolate Acinetobacter baumannii

Directory of Open Access Journals (Sweden)

Kok-Gan Chan

2014-01-01

Full Text Available Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs. These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL and N-octanoyl-homoserine lactone (C8-HSL, was detected.

Differential modulation of enterocyte-like Caco-2 cells after exposure to short-chain fatty acids

NARCIS (Netherlands)

Malago, J.J.; Koninkx, J.F.J.G.; Douma, P.M.; Dirkzwager, A.; Veldman, K.T.; Hendriks, H.G.C.J.M.; Dijk, van J.E.

2003-01-01

The response of intestinal epithelial cells to short-chain fatty acids, which are increasingly used as food additives, was investigated. Human small intestinal epithelial cell model Caco-2 cells were exposed to formate, propionate and butyrate to assess their effect on cellular growth, metabolism,

Endosulfan, pentachlorobenzene and short-chain chlorinated paraffins in background soils from Western Europe

OpenAIRE

Halse, Anne Karine; Schlabach, Martin; Schuster, Jasmin K; Jones, Kevin C; Steinnes, Eiliv; Breivik, Knut

2015-01-01

Soils are major reservoirs for many persistent organic pollutants (POPs). In this study, “newly” regulated POPs i.e. sum endosulfans (a-endosulfan, b-endosulfan, endosulfan sulfate), pentachlorobenzene (PeCB), and short-chain chlorinated paraffins (SCCPs) were determined in background samples from woodland (WL) and grassland (GL) surface soil, collected along an existing latitudinal UK-Norway transect. Statistical analysis, complemented with plots showing the predicted equilibrium distributio...

Oxidative activation of dihydropyridine amides to reactive acyl donors

DEFF Research Database (Denmark)

Funder, Erik Daa; Trads, Julie Brender; Gothelf, Kurt Vesterager

2015-01-01

Amides of 1,4-dihydropyridine (DHP) are activated by oxidation for acyl transfer to amines, alcohols and thiols. In the reduced form the DHP amide is stable towards reaction with amines at room temperature. However, upon oxidation with DDQ the acyl donor is activated via a proposed pyridinium...

Acyl Meldrum's acid derivatives: application in organic synthesis

Science.gov (United States)

Janikowska, K.; Rachoń, J.; Makowiec, S.

2014-07-01

This review is focused on an important class of Meldrum's acid derivatives commonly known as acyl Meldrum's acids. The preparation methods of these compounds are considered including the recently proposed and rather rarely used ones. The chemical properties of acyl Meldrum's acids are described in detail, including thermal stability and reactions with various nucleophiles. The possible mechanisms of these transformations are analyzed. The bibliography includes 134 references.

Characterization of the "Escherichia Coli" Acyl Carrier Protein Phosphodiesterase

Science.gov (United States)

Thomas, Jacob

2009-01-01

Acyl carrier protein (ACP) is a small essential protein that functions as a carrier of the acyl intermediates of fatty acid synthesis. ACP requires the posttranslational attachment of a 4'phosphopantetheine functional group, derived from CoA, in order to perform its metabolic function. A Mn[superscript 2+] dependent enzymatic activity that removes…

Mechanism of MenE inhibition by acyl-adenylate analogues and discovery of novel antibacterial agents.

Science.gov (United States)

Matarlo, Joe S; Evans, Christopher E; Sharma, Indrajeet; Lavaud, Lubens J; Ngo, Stephen C; Shek, Roger; Rajashankar, Kanagalaghatta R; French, Jarrod B; Tan, Derek S; Tonge, Peter J

2015-10-27

MenE is an o-succinylbenzoyl-CoA (OSB-CoA) synthetase in the bacterial menaquinone biosynthesis pathway and is a promising target for the development of novel antibacterial agents. The enzyme catalyzes CoA ligation via an acyl-adenylate intermediate, and we have previously reported tight-binding inhibitors of MenE based on stable acyl-sulfonyladenosine analogues of this intermediate, including OSB-AMS (1), which has an IC50 value of ≤25 nM for Escherichia coli MenE. Herein, we show that OSB-AMS reduces menaquinone levels in Staphylococcus aureus, consistent with its proposed mechanism of action, despite the observation that the antibacterial activity of OSB-AMS is ∼1000-fold lower than the IC50 for enzyme inhibition. To inform the synthesis of MenE inhibitors with improved antibacterial activity, we have undertaken a structure-activity relationship (SAR) study stimulated by the knowledge that OSB-AMS can adopt two isomeric forms in which the OSB side chain exists either as an open-chain keto acid or a cyclic lactol. These studies revealed that negatively charged analogues of the keto acid form bind, while neutral analogues do not, consistent with the hypothesis that the negatively charged keto acid form of OSB-AMS is the active isomer. X-ray crystallography and site-directed mutagenesis confirm the importance of a conserved arginine for binding the OSB carboxylate. Although most lactol isomers tested were inactive, a novel difluoroindanediol inhibitor (11) with improved antibacterial activity was discovered, providing a pathway toward the development of optimized MenE inhibitors in the future.

Genetics Home Reference: very long-chain acyl-CoA dehydrogenase deficiency

Science.gov (United States)

... Management Resources Formal Diagnostic Criteria (1 link) ACT Sheet: Elevated C14:1 +/- other long-chain acylcarnitines (PDF) Formal Treatment/Management Guidelines (1 link) New England Consortium of Metabolic ...

Rivastigmine Improves Appetite by Increasing the Plasma Acyl/Des-Acyl Ghrelin Ratio and Cortisol in Alzheimer Disease

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Yoshiko Furiya

2018-03-01

Full Text Available Background: Weight loss accelerates cognitive decline and increases mortality in patients with dementia. While acetylcholinesterase (AChE inhibitors are known to cause appetite loss, we sometimes encounter patients in whom switching from donepezil (AChE inhibitor to rivastigmine (AChE and butyrylcholinesterase [BuChE] inhibitor improves appetite. Since BuChE inactivates ghrelin, a potent orexigenic hormone, we speculated that rivastigmine improves appetite by inhibiting BuChE-mediated ghrelin inactivation. Methods: The subjects were patients with mild to moderate Alzheimer disease treated with either rivastigmine patch (n = 11 or donepezil (n = 11 for 6 months. Before and after treatment, we evaluated appetite (0, decreased; 1, slightly decreased; 2, normal; 3, slightly increased; 4, increased, cognitive function, and blood biochemical variables, including various hormones. Results: Rivastigmine treatment significantly improved appetite (from 1.6 ± 0.5 to 2.6 ± 0.7, whereas donepezil treatment did not (from 2.0 ± 0.0 to 1.8 ± 0.4. Simultaneously, rivastigmine, but not donepezil, significantly decreased the serum cholinesterase activity (from 304.3 ± 60.5 to 246.8 ± 78.5 IU/L and increased the cortisol level (from 11.86 ± 3.12 to 14.61 ± 3.29 μg/dL and the acyl/des-acyl ghrelin ratio (from 4.03 ± 2.96 to 5.28 ± 2.72. The levels of leptin, insulin, total ghrel­in, and cognitive function were not significantly affected by either treatment. Conclusions: Our results suggest that compared with donepezil, rivastigmine has the advantage of improving appetite by increasing the acyl/des-acyl ghrelin ratio and cortisol level, thereby preventing weight loss.

Genetics Home Reference: short/branched chain acyl-CoA dehydrogenase deficiency

Science.gov (United States)

... unclear why some people with SBCAD deficiency develop health problems and others do not. Doctors suggest that in some cases, signs and symptoms may be triggered by infections, prolonged periods without food (fasting), or an increased amount of protein-rich foods ...

Lipopolysaccharides with acylation defects potentiate TLR4 signaling and shape T cell responses.

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Anna Martirosyan

Full Text Available Lipopolysaccharides or endotoxins are components of Gram-negative enterobacteria that cause septic shock in mammals. However, a LPS carrying hexa-acyl lipid A moieties is highly endotoxic compared to a tetra-acyl LPS and the latter has been considered as an antagonist of hexa-acyl LPS-mediated TLR4 signaling. We investigated the relationship between the structure and the function of bacterial LPS in the context of human and mouse dendritic cell activation. Strikingly, LPS with acylation defects were capable of triggering a strong and early TLR4-dependent DC activation, which in turn led to the activation of the proteasome machinery dampening the pro-inflammatory cytokine secretion. Upon activation with tetra-acyl LPS both mouse and human dendritic cells triggered CD4(+ T and CD8(+ T cell responses and, importantly, human myeloid dendritic cells favored the induction of regulatory T cells. Altogether, our data suggest that LPS acylation controlled by pathogenic bacteria might be an important strategy to subvert adaptive immunity.

1,5-Anhydro-D-fructose: regioselective acylation with fatty acids

DEFF Research Database (Denmark)

Lundt, Inge; Andersen, Søren Møller; Marcussen, Jan

1999-01-01

Regioselective acylation of 1,5-anhydro-D-fructose was performed with dodecanoic acid to give 1,5-anhydro-6-O-dodecanoyl-D-fructose, chemically in 50% yield and enzymatically in quantitative yield. Quantitative conversions were also obtained using hexadecanoic and octadecanoic acids as acyl donors...

Acyl transfer from membrane lipids to peptides is a generic process.

Science.gov (United States)

Dods, Robert H; Bechinger, Burkhard; Mosely, Jackie A; Sanderson, John M

2013-11-15

The generality of acyl transfer from phospholipids to membrane-active peptides has been probed using liquid chromatography-mass spectrometry analysis of peptide-lipid mixtures. The peptides examined include melittin, magainin II, PGLa, LAK1, LAK3 and penetratin. Peptides were added to liposomes with membrane lipid compositions ranging from pure phosphatidylcholine (PC) to mixtures of PC with phosphatidylethanolamine, phosphatidylserine or phosphatidylglycerol. Experiments were typically conducted at pH7.4 at modest salt concentrations (90 mM NaCl). In favorable cases, lipidated peptides were further characterized by tandem mass spectrometry methods to determine the sites of acylation. Melittin and magainin II were the most reactive peptides, with significant acyl transfer detected under all conditions and membrane compositions. Both peptides were lipidated at the N-terminus by transfer from PC, phosphatidylethanolamine, phosphatidylserine or phosphatidylglycerol, as well as at internal sites: lysine for melittin; serine and lysine for magainin II. Acyl transfer could be detected within 3h of melittin addition to negatively charged membranes. The other peptides were less reactive, but for each peptide, acylation was found to occur in at least one of the conditions examined. The data demonstrate that acyl transfer is a generic process for peptides bound to membranes composed of diacylglycerophospholipids. Phospholipid membranes cannot therefore be considered as chemically inert toward peptides and by extension proteins. © 2013. Published by Elsevier Ltd. All rights reserved.

Development of Probiotic Fruit Juices Using Lactobacillus rhamnosus GR-1 Fortified with Short Chain and Long Chain Inulin Fiber

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Jessica White

2018-04-01

Full Text Available Typically, probiotics are consumed in dairy based products such as yogurt. However, given the rise in various diet types, non-dairy alternatives have been developed, such as inoculating fruit juices with probiotics. Lactobacillus rhamnosus GR-1 is a probiotic strain exerting a number of human health benefits such as the prevention of urinary tract infections. Therefore, the objective of this study was to determine the viability of L. rhamnosus GR-1 in apple cider, orange, and grape juice when fortified with either 4% short chain or 4% long chain inulin fiber over 72 h of fermentation and 30 days of refrigerated storage. The secondary objective was to determine consumer acceptability of apple cider and orange juice samples using the hedonic scale. All of the fruit juice samples achieved a mean viable count of at least 107 CFU/mL during 72 h of fermentation and 30 days of refrigerated storage. According to the sensory evaluation, which evaluated samples according to appearance, flavor, texture, and overall acceptability, apple cider juice with long chain inulin fiber proved to have the highest score for all characteristics except appearance. Therefore, this study indicated a potential for probiotic fruit juices as a valid alternative to dairy based probiotic products.

A targeted metabolomic protocol for short-chain fatty acids and branched-chain amino acids.

Science.gov (United States)

Zheng, Xiaojiao; Qiu, Yunping; Zhong, Wei; Baxter, Sarah; Su, Mingming; Li, Qiong; Xie, Guoxiang; Ore, Brandon M; Qiao, Shanlei; Spencer, Melanie D; Zeisel, Steven H; Zhou, Zhanxiang; Zhao, Aihua; Jia, Wei

2013-08-01

Research in obesity and metabolic disorders that involve intestinal microbiota demands reliable methods for the precise measurement of the short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) concentration. Here, we report a rapid method of simultaneously determining SCFAs and BCAAs in biological samples using propyl chloroformate (PCF) derivatization followed by gas chromatography mass spectrometry (GC-MS) analysis. A one-step derivatization using 100 µL of PCF in a reaction system of water, propanol, and pyridine (v/v/v = 8:3:2) at pH 8 provided the optimal derivatization efficiency. The best extraction efficiency of the derivatized products was achieved by a two-step extraction with hexane. The method exhibited good derivatization efficiency and recovery for a wide range of concentrations with a low limit of detection for each compound. The relative standard deviations (RSDs) of all targeted compounds showed good intra- and inter-day (within 7 days) precision (< 10%), and good stability (< 20%) within 4 days at room temperature (23-25 °C), or 7 days when stored at -20 °C. We applied our method to measure SCFA and BCAA levels in fecal samples from rats administrated with different diet. Both univariate and multivariate statistics analysis of the concentrations of these target metabolites could differentiate three groups with ethanol intervention and different oils in diet. This method was also successfully employed to determine SCFA and BCAA in the feces, plasma and urine from normal humans, providing important baseline information of the concentrations of these metabolites. This novel metabolic profile study has great potential for translational research.

Fermentation to short-chain fatty acids and lactate in human faecal batch cultures. Intra- and inter-individual variations versus variations caused by changes in fermented saccharides

DEFF Research Database (Denmark)

Mortensen, P B; Hove, H; Clausen, M R

1991-01-01

in homogenates pooled from three individuals increased short-chain fatty acid production linearly. Amounts and ratios of short-chain fatty acids formed were highly dependent on the type of substrate fermented. Fermentable saccharides increased ammonia assimilation, in contrast to the metabolic inert cellulose...

Effects of Short-Term Jump Squat Training With and Without Chains on Strength and Power in Recreational Lifters

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David C. Archer

2016-10-01

Full Text Available Background: The use of chains in resistance training is a way to accommodate the muscular strength curve. Short-term training and jump squats have been shown to increase back squat strength, but not in conjunction with each other or with chains. Jump squats have also been used to increase jump height and power. Objectives: The purpose of this study was to investigate the effects of short-term jump squat training with and without chains on strength and power. Methods: Thirty-one resistance-trained men volunteered to participate (age = 23.87 ± 2.2 years, height=174.87 ± 6.94 cm, mass = 82.74 ± 14.95 kg and were randomly assigned to one of three groups [control (C = 10, no chains (NC =10, or chains (CH = 11]. Participants had their jump height (VJ and back squat strength (BS tested before and after a week of training. The NC and CH groups performed three training sessions consisting of five sets of three reps of jump squats at 30% 1RM with 30s rest between sets. The CH group had 20% of their load added by chains when standing erect. The C group did not train. Results: A 3 (group: CH, NC, C x 2 (time: pre, post mixed factor ANOVA revealed a significant (p = 0.006 interaction for back squat 1RM. Both the CH (pre 142.56 ± 20.40 kg; post 145.66 ± 19.59 kg and NC (pre 150.00 ± 15.23 kg; post 154.77 ± 15.09 kg groups significantly increased while the C (pre 157.27 ± 25.35 kg; post 156.36 ± 24.85 kg group showed no difference. There were no significant interactions (p =0.32 or main effects for VJ (C = pre 50.59 ± 9.39cm; post 51.29 ± 9.68cm; NC = pre 55.29 ± 5.23cm; post 57.39 ± 5.22cm; CH = pre 46.19 ± 5.02; post 47.45 ± 4.62. Conclusions: The CH group was able to increase strength while lifting less overall weight. Coaches may use short-term training with chains to yield a similar increase in back squat strength as without chains. Keywords: variable resistance, back squats, novel, vertical jump

Defect-induced conductance oscillations in short atomic chains

International Nuclear Information System (INIS)

Wawrzyniak-Adamczewska, M; Kostyrko, T

2012-01-01

Electronic transport through a junction made of two gold electrodes connected with a gold chain containing a silver impurity is analyzed with a tight binding model and the density-functional theory. It is shown that the conductance depends in a simple way on the position of the impurity in the chain and the parity of the total number of atoms of the chain. For an odd chain the conductance takes on a higher value when the Ag impurity substitutes an even Au atom in the chain, and a lower one for an odd position of the Ag atom. In the case of an even chain the conductance hardly depends on the position of the Ag atom. This new kind of a defect-induced parity oscillation of the conductance is significantly more prominent than the well-known even-odd effect related to the dependence of the conductance on the parity of number of atoms in perfect chains. (paper)

Cost-effectiveness analysis of universal newborn screening for medium chain acyl-CoA dehydrogenase deficiency in France.

Science.gov (United States)

Hamers, Françoise F; Rumeau-Pichon, Catherine

2012-06-08

Five diseases are currently screened on dried blood spots in France through the national newborn screening programme. Tandem mass spectrometry (MS/MS) is a technology that is increasingly used to screen newborns for an increasing number of hereditary metabolic diseases. Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is among these diseases. We sought to evaluate the cost-effectiveness of introducing MCADD screening in France. We developed a decision model to evaluate, from a societal perspective and a lifetime horizon, the cost-effectiveness of expanding the French newborn screening programme to include MCADD. Published and, where available, routine data sources were used. Both costs and health consequences were discounted at an annual rate of 4%. The model was applied to a French birth cohort. One-way sensitivity analyses and worst-case scenario simulation were performed. We estimate that MCADD newborn screening in France would prevent each year five deaths and the occurrence of neurological sequelae in two children under 5 years, resulting in a gain of 128 life years or 138 quality-adjusted life years (QALY). The incremental cost per year is estimated at €2.5 million, down to €1 million if this expansion is combined with a replacement of the technology currently used for phenylketonuria screening by MS/MS. The resulting incremental cost-effectiveness ratio (ICER) is estimated at €7 580/QALY. Sensitivity analyses indicate that while the results are robust to variations in the parameters, the model is most sensitive to the cost of neurological sequelae, MCADD prevalence, screening effectiveness and screening test cost. The worst-case scenario suggests an ICER of €72 000/QALY gained. Although France has not defined any threshold for judging whether the implementation of a health intervention is an efficient allocation of public resources, we conclude that the expansion of the French newborn screening programme to MCADD would appear to be cost

Analysis of short-chain acids from anaerobic bacteria by high-performance liquid chromatography.

OpenAIRE

Guerrant, G O; Lambert, M A; Moss, C W

1982-01-01

A standard mixture of 25 short-chain fatty acids was resolved by high-performance liquid chromatography, using an Aminex HPX-87 column. The acids produced in culture media by anaerobic bacteria were analyzed by high-performance liquid chromatography after extraction with ether and reextraction into a small volume of 0.1 N NaOH. The presence of fumaric acid in culture extracts of Peptostreptococcus anaerobius was confirmed by gas chromatography-mass spectrometry analysis of the trapped eluent ...

Purification of specific structured lipids by distillation: Effects on acyl migration

DEFF Research Database (Denmark)

Xu, Xuebing; Skands, A.; Adler-Nissen, Jens

2001-01-01

The cause and effects of acyl migration during the purification of specific structured lipids by distillation were studied in a conventional batch deodorizer with stripping steam. The mixture of specific structured lipids produced by lipase-catalyzed acidolysis between rapeseed oil and capric acid...... influenced the rate of acyl migration, and their combinations made the effect more severe. However, diacylglycerols were found to be the main reason for acyl migration. In the distillation of the specific structured lipid product mixture, distillation temperature and time were the main factors to determine...... the degree of acyl migration and the extent of separation of free fatty acids. The results indicate that more efficient separation technology should be used to improve the quality of the purified structured lipids. in order to reduce the distillation temperature, vacuum should be made as low as possible...

Clarification on the decarboxylation mechanism in KasA based on the protonation state of key residues in the acyl-enzyme state.

Science.gov (United States)

Lee, Wook; Engels, Bernd

2013-07-11

The β-ketoacyl ACP synthase I (KasA) is a promising drug target because it is essential for the survival of Mycobacterium tuberculosis , a causative agent of tuberculosis. It catalyzes a condensation reaction that comprises three steps. The resulting elongated acyl chains are subsequently needed for the cell wall construction. While the mechanism of the first step (acylation of Cys171 in the active site) is straightforward already, the second step (decarboxylation of malonyl substrate) has been controversial due to the difficulty in determining the correct protonation states of the involved residues (His311, His345, Lys340, Glu354). Available experimental data suggest three possible mechanisms which differ considerably. They are not consistent with each other because these studies could not be performed for KasA at the beginning of decarboxylation step (acyl-enzyme state of KasA). Instead, different mutants had to be used which are expected to resemble this situation. In this first computational study about this topic, we use the free energy perturbation (FEP) method to compute the relevant pKa values in the acyl-enzyme state of KasA and use molecular dynamics (MD) simulations to rationalize the results. Subsequent density functional theory (DFT)-based quantum mechanical/molecular mechanical (QM/MM) MD simulations and umbrella samplings have been used to disentangle the close relationships between the protonation states of the involved residues. By these simulations, we can address the preferred protonation states and roles of the residues involved in decarboxylation reaction, thereby suggesting the possible mechanism for the decarboxylation step.

Copper(II)/amine synergistically catalyzed enantioselective alkylation of cyclic N-acyl hemiaminals with aldehydes.

Science.gov (United States)

Sun, Shutao; Mao, Ying; Lou, Hongxiang; Liu, Lei

2015-07-07

The first catalytic asymmetric alkylation of N-acyl quinoliniums with aldehydes has been described. A copper/amine synergistic catalytic system has been developed, allowing the addition of functionalized aldehydes to a wide range of electronically varied N-acyl quinoliniums in good yields with excellent enantiocontrol. The synergistic catalytic system was also effective for N-acyl dihydroisoquinoliniums and β-caboliniums, demonstrating the general applicability of the protocol in the enantioselective alkylation of diverse cyclic N-acyl hemiaminals.

Cholinesterase catalyzed hydrolysis of O-acyl derivatives of serotonin

International Nuclear Information System (INIS)

Makhaeva, G.F.; Suvorov, N.N.; Ginodman, L.N.; Antonov, V.K.; AN SSSR, Moscow. Inst. Bioorganicheskoj Khimii)

1977-01-01

Hydrolysis of O acyl serotonin derivatives containing the residues of monocarbon dicarbon and amino acids under the effect of horse serum butyryl cholinesterase and bull erythrocytic acetylcholinesterase has been studied. It has been established, that acetylcholinesterase hydrolizes O acetylserotonin only; butyrylcholinesterase hydrolizes all the compounds investigated, except for 5,5'-terephthaloildioxytriptamine. The kinetic parameters of hydrolysis were determined. O acyl serotonin derivatives turned out good substrates of butylrylcholinesterase; serotonin and 5.5'-terephtaloildioxytriptamine are effective competitine inhibitors of the enzyme. Estimating of resistance of O acyl serotonin derivatines to blood cholinesterase effect under physiological conditions shows that the compounds investigated with the exception of 5,5'-terephthaloildioxytriptamine must be quickly hydrolyzed under butyrylcholinesterase action. 5,5'-terephthaloildioxytriptamine is suggested as a radioprotective preparation with the prolonged effect, which agrees with the biological test results

FUNCTIONAL SHORT FOOD SUPPLY CHAINS IN THE FIELD OF ROMANIAN RURAL TOURISM. CASE STUDY: HARGHITA AND NEAMȚ COUNTIES

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Lucian TANASA

2015-08-01

Full Text Available Nowadays, one cannot talk about an authentic rural tourism within a certain destination without emphasizing the local cultural heritage (cultural landscape, customs and traditions, gastronomy and so on. In the existing context, the local gastronomy is perceived as a marketing instrument efficient in differentiating the rural touristic destinations. A special place in the development of the traditional cuisine is represented by the setting up and the promotion of the short food supply chains which can be achieved by sustaining the small local producers and by putting into practice an environment-friendly traditional agriculture. Sustaining the partnerships between the owners of accommodation units and the small local agricultural producers represents an essential element in putting into practice a sustainable and qualitative rural tourism. Romania has a substantial potential as regards the enhancement of short food supply chains thanks to: the large number of semi-subsistence agricultural farms (with an area under 5 hectares, the „village-town connection” as regards the food procurement, especially from acquaintances and relatives and the carrying on of a traditional agriculture at a large scale in the rural households.The case studies emphasized in the current paper (Harghita and Neamţ Counties focus on the existence of short food supply chains, functional in the rural tourism sector under very different ways: touristic sheepfolds, trout farms, inns, authentic holiday villages, peasant guest houses etc.

Plant Acyl-CoA:Lysophosphatidylcholine Acyltransferases (LPCATs) Have Different Specificities in Their Forward and Reverse Reactions*

Science.gov (United States)

Lager, Ida; Yilmaz, Jenny Lindberg; Zhou, Xue-Rong; Jasieniecka, Katarzyna; Kazachkov, Michael; Wang, Peng; Zou, Jitao; Weselake, Randall; Smith, Mark A.; Bayon, Shen; Dyer, John M.; Shockey, Jay M.; Heinz, Ernst; Green, Allan; Banas, Antoni; Stymne, Sten

2013-01-01

Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) enzymes have central roles in acyl editing of phosphatidylcholine (PC). Plant LPCAT genes were expressed in yeast and characterized biochemically in microsomal preparations of the cells. Specificities for different acyl-CoAs were similar for seven LPCATs from five different species, including species accumulating hydroxylated acyl groups in their seed oil, with a preference for C18-unsaturated acyl-CoA and low activity with palmitoyl-CoA and ricinoleoyl (12-hydroxyoctadec-9-enoyl)-CoA. We showed that Arabidopsis LPCAT1 and LPCAT2 enzymes catalyzed the acylation and de-acylation of both sn positions of PC, with a preference for the sn-2 position. When acyl specificities of the Arabidopsis LPCATs were measured in the reverse reaction, sn-2-bound oleoyl, linoleoyl, and linolenoyl groups from PC were transferred to acyl-CoA to a similar extent. However, a ricinoleoyl group at the sn-2-position of PC was removed 4–6-fold faster than an oleoyl group in the reverse reaction, despite poor utilization in the forward reaction. The data presented, taken together with earlier published reports on in vivo lipid metabolism, support the hypothesis that plant LPCAT enzymes play an important role in regulating the acyl-CoA composition in plant cells by transferring polyunsaturated and hydroxy fatty acids produced on PC directly to the acyl-CoA pool for further metabolism or catabolism. PMID:24189065

LOCATION OF ACYL GROUPS ON TWO PARTLY ACYLATED GLYCOLIPIDS FROM STRAINS OF USTILAGO (SMUT FUNGI),

Science.gov (United States)

erythritol from Ustilago sp. (probably U. nuda (Jens.) Rostr. = U. tritici (Pers.) Rostr.) PRL-627 were acetalated with methyl vinyl ether, deacylated...Partly acylated ustilagic acids 8 (from Ustilago maydis (DC) Corda (= U. zeae Unger) PRL-119), consisting of partially esterified beta-cellobiosyl

Fasting serum concentration of short-chain fatty acids in subjects with microscopic colitis and celiac disease

DEFF Research Database (Denmark)

Jakobsdottir, Greta; Bjerregaard, Jens Holst; Skovbjerg, Hanne

2013-01-01

Short-chain fatty acids (SCFAs), particularly propionic and butyric acids, have been shown to have many positive health effects. The amount and type of SCFAs formed from dietary fibre by the colonic microbiota depends on the substrate available and is reflected in blood. The total intake and type...

Stomach regulates energy balance via acylated ghrelin and desacyl ghrelin

OpenAIRE

Asakawa, A; Inui, A; Fujimiya, M; Sakamaki, R; Shinfuku, N; Ueta, Y; Meguid, M M; Kasuga, M

2005-01-01

Background/Aims: The gastric peptide ghrelin, an endogenous ligand for growth-hormone secretagogue receptor, has two major molecular forms: acylated ghrelin and desacyl ghrelin. Acylated ghrelin induces a positive energy balance, while desacyl ghrelin has been reported to be devoid of any endocrine activities. The authors examined the effects of desacyl ghrelin on energy balance.

THE LATEST ADVANCEMENTS IN THE ACYLATION REACTIONS VIA CROSS-DEHYDROGENATIVE COUPLING AND/OR METAL CATALYSTS

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Soykan Ağar

2017-12-01

Full Text Available There are quite many examples in the scientific literature regarding the acylation reactions, especially the metal-catalyzed acylation reactions, metal-free acylation reactions, metal-catalyzed acylation via cross-dehydrogenative coupling (CDC reactions and metal-free acylation via cross-dehydrogenative coupling (CDC reactions. In this review paper, the most important examples of these domains were brought together and their mechanisms were exhibited in a clear, chronological format. Following these, the best example study towards green chemistry with a metal-free and high-yielding route was mentioned and discussed to demonstrate what has achieved in this field regarding the new acylation reaction mechanisms using the advantages of cross-dehydrogenative coupling (CDC reactions. The most prominent studies regarding these domains have been examined thoroughly and the latest progress in this field was explained in detail.

Acylated flavonol tri- and tetraglycosides in the flavonoid metabolome of Cladrastis kentukea (Leguminosae).

Science.gov (United States)

Kite, Geoffrey C; Rowe, Emily R; Lewis, Gwilym P; Veitch, Nigel C

2011-04-01

The foliar metabolome of Cladrastis kentukea (Leguminosae) contains a complex mixture of flavonoids including acylated derivatives of the 3-O-rhamnosyl(1→2)[rhamnosyl(1→6)]-galactosides of kaempferol and quercetin and their 7-O-rhamnosides, together with an array of non-acylated kaempferol and quercetin di-, tri- and tetraglycosides. Thirteen of the acylated flavonoids, 12 of which had not been reported previously, were characterised by spectroscopic and chemical methods. Eight of these were the four isomers of kaempferol 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E/Z-p-coumaroyl-β-d-galactopyranoside) and their 7-O-α-l-rhamnopyranosides, and three were isomers of quercetin 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E/Z-p-coumaroyl-β-d-galactopyranoside) - the remaining 4Z isomer was identified by LC-UV-MS analysis of a crude extract. The final two acylated flavonoids characterised by NMR were the 3E and 4E isomers of kaempferol 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E-feruloyl-β-d-galactopyranoside)-7-O-α-l-rhamnopyranoside while the 3Z and 4Z isomers were again detected by LC-UV-MS. Using the observed fragmentation behaviour of the isolated compounds following a variety of MS experiments, a further 18 acylated flavonoids were given tentative structures by LC-MS analysis of a crude extract. Acylated flavonoids were absent from the flowers of C. kentukea, which contained an array of non-acylated kaempferol and quercetin glycosides. Immature fruits contained kaempferol 3-O-α-rhamnopyranosyl(1→2)[α-rhamnopyranosyl(1→6)]-β-galactopyranoside and its 7-O-α-rhamnopyranoside as the major flavonoids with acylated flavonoids, different from those in the leaves, only present as minor constituents. The presence of acylated flavonoids distinguishes the foliar flavonoid metabolome of C. kentukea from that of a closely related legume, Styphnolobium japonicum, which contains a similar

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

DEFF Research Database (Denmark)

Røjen, B A; Lund, P; Kristensen, N B

2008-01-01

Three ruminally cannulated and multicatheterised lactating dairy cows were used to investigate the effect of different supplement strategies to fresh clover grass on urea and short-chain fatty acid (SCFA) metabolism in a zero-grazing experiment with 24-h blood and ruminal samplings....

Synthesis and emulsifying properties of carbohydrate fatty acid esters produced from Agave tequilana fructans by enzymatic acylation.

Science.gov (United States)

Casas-Godoy, Leticia; Arrizon, Javier; Arrieta-Baez, Daniel; Plou, Francisco J; Sandoval, Georgina

2016-08-01

Carbohydrate fatty acid esters are non-ionic surfactants with a broad spectrum of applications. These molecules are generally synthesized using short carbohydrates or linear fructans; however in this research carbohydrate fatty acid esters were produced for the first time with branched fructans from Agave tequilana. Using immobilized lipases we successfully acylated A. tequilana fructans with vinyl laurate, obtaining products with different degrees of polymerization (DP). Lipozyme 435 was the most efficient lipase to catalyze the transesterification reaction. HPLC and ESI-MS analysis proved the presence of a mixture of acylated products as a result of the chemical complexity of fructans in the A. tequilana. The ESI-MS spectra showed a molecular mass shift between 183 and 366g/mol for fructooligosaccharides with a DP lower than 6, which indicated the presence of Agave fructans that had been mono- and diacylated with lauric acid. The carbohydrate fatty acid esters (CFAE) obtained showed good emulsifying properties in W/O emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

S2p core level spectroscopy of short chain oligothiophenes

Science.gov (United States)

Baseggio, O.; Toffoli, D.; Stener, M.; Fronzoni, G.; de Simone, M.; Grazioli, C.; Coreno, M.; Guarnaccio, A.; Santagata, A.; D'Auria, M.

2017-12-01

The Near-Edge X-ray-Absorption Fine-Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) of short-chain oligothiophenes (thiophene, 2,2'-bithiophene, and 2,2':5',2″-terthiophene) in the gas phase have been measured in the sulfur L2,3-edge region. The assignment of the spectral features is based on the relativistic two-component zeroth-order regular approximation time dependent density functional theory approach. The calculations allow us to estimate both the contribution of the spin-orbit splitting and of the molecular-field splitting to the sulfur binding energies and give results in good agreement with the experimental measurements. The deconvolution of the calculated S2p NEXAFS spectra into the two manifolds of excited states converging to the LIII and LII edges facilitates the attribution of the spectral structures. The main S2p NEXAFS features are preserved along the series both as concerns the energy positions and the nature of the transitions. This behaviour suggests that the electronic and geometrical environment of the sulfur atom in the three oligomers is relatively unaffected by the increasing chain length. This trend is also observed in the XPS spectra. The relatively simple structure of S2p NEXAFS spectra along the series reflects the localized nature of the virtual states involved in the core excitation process.

5,5'-Dithiobis-(2-nitrobenzoic acid) as a probe for a non-essential cysteine residue at the medium chain acyl-coenzyme A dehydrogenase binding site of the human 'electron transferring flavoprotein' (ETF).

Science.gov (United States)

Parker, A; Engel, P C

1999-01-01

Human 'electron transferring flavoprotein' (ETF) was inactivated by the thiol-specific reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). The kinetic profile showed the reaction followed pseudo-first-order kinetics during the initial phase of inactivation. Monitoring the release of 5-thio-2-nitrobenzoate (TNB) showed that modification of 1 cysteine residue was responsible for the loss of activity. The inactivation of ETF by DTNB could be reversed upon incubation with thiol-containing reagents. The loss of activity was prevented by the inclusion of medium chain acyl-CoA dehydrogenase (MCAD) and octanoyl-CoA. Cyanolysis of the DTNB modified-ETF with KCN led to the release of TNB accompanied presumably by the formation of the thio-cyano enzyme and with almost full recovery of activity. Conservation studies and the lack of 100% inactivation, however, suggested that this cysteine residue is not essential for the interaction with MCAD.

[Clinical features and ACADVL gene mutation spectrum analysis of 11 Chinese patients with very long chain acyl-CoA dehydrogenase deficiency].

Science.gov (United States)

Jinjun, Cao; Wenjuan, Qiu; Ruinan, Zhang; Jun, Ye; Lianshu, Han; Huiwen, Zhang; Qigang, Zhang; Xuefan, Gu

2015-04-01

To investigate the clinical and laboratory features of very long chain acyl-CoA dehydrogenase deficiency ( VLCADD ) and the correlations between its genotype and phenotype. Eleven patients diagnosed as VLCADD of Shanghai Jiaotong University School of Medicine seen from September 2006 to May 2014 were included. There were 9 boys and 2 girls, whose age was 2 d-17 years. Analysis was performed on clinical features, routine laboratory examination, and tandem mass spectrometry (MS-MS) , gas chromatography mass spectrometry (GC-MS) and genetic analysis were conducted. All cases had elevated levels of blood tetradecanoylcarnitine (C14:1) recognized as the characteristic biomarker for VLCADD. The eleven patients were classified into three groups: six cases in neonatal onset group, three in infancy onset group form patients and two in late onset group. Neonatal onset patients were characterized by hypoactivity, hypoglycemia shortly after birth. Infancy onset patients presented hepatomegaly and hypoglycemia in infancy. The two adolescent patients showed initial manifestations of exercise intolerance or rhabdomyolysis. Six of the eleven patients died at the age of 2-8 months, including four neonatal onset and two infant onset patients, with one or two null mutations. The other two neonatal onset patients were diagnosed since early birth through neonatal screening and their clinical manifestation are almost normal after treatments. Among 11 patients, seventeen different mutations in the ACADVL gene were identified, with a total mutation detection rate of 95.45% (21/22 alleles), including eleven reported mutations ( p. S22X, p. G43D, p. R511Q, p. W427X, p. A213T, p. C215R, p. G222R, p. R450H, p. R456H, c. 296-297delCA, c. 1605 + 1G > T) and six novel mutations (p. S72F, p. Q100X, p. M437T, p. D466Y, c. 1315delG insAC, IVS7 + 4 A > G). The p. R450H was the most frequent mutation identified in three alleles (13.63%, 3/22 alleles), followed by p. S22X and p. D466Y mutations which

Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

OpenAIRE

Marijanović-Rajčić, M.; Senta, A.

2008-01-01

The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1). The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašna...

Emission control strategies for short-chain chloroparaffins in two semi-hypothetical case cities

DEFF Research Database (Denmark)

Eriksson, Eva; Revitt, M.; Lützhøft, Hans-Christian Holten

2012-01-01

The short-chain chloroparaffins (SCCP), (C10-13 chloroalkanes) are identified in the European Water Framework Directive, as priority hazardous substances. Within the ScorePP project, the aim is to develop emission control strategies that can be employed to reduce emissions from urban areas...... into receiving waters. Six different scenarios for mitigating SCCP emissions in two different semi-hypothetical case cities representing eastern inland and northern coastal conditions have been evaluated. The analysis, associated with scenario uncertainty, indicates that the EU legislation, Best Available...

Critical Role for Very-Long Chain Sphingolipids in Invariant Natural Killer T Cell Development and Homeostasis.

Science.gov (United States)

Saroha, Ashish; Pewzner-Jung, Yael; Ferreira, Natalia S; Sharma, Piyush; Jouan, Youenn; Kelly, Samuel L; Feldmesser, Ester; Merrill, Alfred H; Trottein, François; Paget, Christophe; Lang, Karl S; Futerman, Anthony H

2017-01-01

The role of sphingolipids (SLs) in the immune system has come under increasing scrutiny recently due to the emerging contributions that these important membrane components play in regulating a variety of immunological processes. The acyl chain length of SLs appears particularly critical in determining SL function. Here, we show a role for very-long acyl chain SLs (VLC-SLs) in invariant natural killer T ( i NKT) cell maturation in the thymus and homeostasis in the liver. Ceramide synthase 2-null mice, which lack VLC-SLs, were susceptible to a hepatotropic strain of lymphocytic choriomeningitis virus, which is due to a reduction in the number of i NKT cells. Bone marrow chimera experiments indicated that hematopoietic-derived VLC-SLs are essential for maturation of i NKT cells in the thymus, whereas parenchymal-derived VLC-SLs are crucial for i NKT cell survival and maintenance in the liver. Our findings suggest a critical role for VLC-SL in i NKT cell physiology.

Distribution, activity and function of short-chain alkane degrading phylotypes in hydrothermal vent sediments

Science.gov (United States)

Adams, M. M.; Joye, S. B.; Hoarfrost, A.; Girguis, P. R.

2012-12-01

Global geochemical analyses suggest that C2-C4 short chain alkanes are a common component of the utilizable carbon pool in deep-sea sediments worldwide and have been found in diverse ecosystems. From a thermodynamic standpoint, the anaerobic microbial oxidation of these aliphatic hydrocarbons is more energetically yielding than the anaerobic oxidation of methane (AOM). Therefore, the preferential degradation of these hydrocarbons may compete with AOM for the use of oxidants such as sulfate, or other potential oxidants. Such processes could influence the fate of methane in the deep-sea. Sulfate-reducing bacteria (SRB) from hydrocarbon seep sediments of the Gulf of Mexico and Guaymas Basin have previously been enriched that anaerobically oxidize short chain alkanes to generate CO2 with the preferential utilization of 12C-enriched alkanes (Kniemeyer et al. 2007). Different temperature regimens along with multiple substrates were tested and a pure culture (deemed BuS5) was isolated from mesophilic enrichments with propane or n-butane as the sole carbon source. Through comparative sequence analysis, strain BuS5 was determined to cluster with the metabolically diverse Desulfosarcina / Desulfococcus cluster, which also contains the SRB found in consortia with anaerobic, methane-oxidizing archaea in seep sediments. Enrichments from a terrestrial, low temperature sulfidic hydrocarbon seep also corroborated that propane degradation occurred with most bacterial phylotypes surveyed belonging to the Deltaproteobacteria, particularly Desulfobacteraceae (Savage et al. 2011). To date, no microbes capable of ethane oxidation or anaerobic C2-C4 alkane oxidation at thermophilic temperature have been isolated. The sediment-covered, hydrothermal vent systems found at Middle Valley (Juan de Fuca Ridge, eastern Pacific Ocean) are a prime environment for investigating mesophilic to thermophilic anaerobic oxidation of short-chain alkanes, given the elevated temperatures and dissolved

Short-chain fatty acids and poly-beta-hydroxyalkanoates: (New) Biocontrol agents for a sustainable animal production.

Science.gov (United States)

Defoirdt, Tom; Boon, Nico; Sorgeloos, Patrick; Verstraete, Willy; Bossier, Peter

2009-01-01

Because of the risk of antibiotic resistance development, there is a growing awareness that antibiotics should be used more carefully in animal production. However, a decreased use of antibiotics could result in a higher frequency of pathogenic bacteria, which in its turn could lead to a higher incidence of infections. Short-chain fatty acids (SCFAs) have long been known to exhibit bacteriostatic activity. These compounds also specifically downregulate virulence factor expression and positively influence the gastrointestinal health of the host. As a consequence, there is currently considerable interest in SCFAs as biocontrol agents in animal production. Polyhydroxyalkanoates (PHAs) are polymers of beta-hydroxy short-chain fatty acids. Currently, PHAs are applied as replacements for synthetic polymers. These biopolymers can be depolymerised by many different microorganisms that produce extracellular PHA depolymerases. Interestingly, different studies provided some evidence that PHAs can also be degraded upon passage through the gastrointestinal tract of animals and consequently, adding these compounds to the feed might result in biocontrol effects similar to those described for SCFAs.

The Acylation State of Surface Lipoproteins of Mollicute Acholeplasma laidlawii*

Science.gov (United States)

Serebryakova, Marina V.; Demina, Irina A.; Galyamina, Maria A.; Kondratov, Ilya G.; Ladygina, Valentina G.; Govorun, Vadim M.

2011-01-01

Acylation of the N-terminal Cys residue is an essential, ubiquitous, and uniquely bacterial posttranslational modification that allows anchoring of proteins to the lipid membrane. In Gram-negative bacteria, acylation proceeds through three sequential steps requiring lipoprotein diacylglyceryltransferase, lipoprotein signal peptidase, and finally lipoprotein N-acyltransferase. The apparent lack of genes coding for recognizable homologs of lipoprotein N-acyltransferase in Gram-positive bacteria and Mollicutes suggests that the final step of the protein acylation process may be absent in these organisms. In this work, we monitored the acylation state of eight major lipoproteins of the mollicute Acholeplasma laidlawii using a combination of standard two-dimensional gel electrophoresis protein separation, blotting to nitrocellulose membranes, and MALDI-MS identification of modified N-terminal tryptic peptides. We show that for each A. laidlawii lipoprotein studied a third fatty acid in an amide linkage on the N-terminal Cys residue is present, whereas diacylated species were not detected. The result thus proves that A. laidlawii encodes a lipoprotein N-acyltransferase activity. We hypothesize that N-acyltransferases encoded by genes non-homologous to N-acyltransferases of Gram-negative bacteria are also present in other mollicutes and Gram-positive bacteria. PMID:21540185

Exploring Cooperative Effects in Oxidative NHC Catalysis: Regioselective Acylation of Carbohydrates.

Science.gov (United States)

Cramer, David L; Bera, Srikrishna; Studer, Armido

2016-05-23

The utility of oxidative NHC catalysis for both the regioselective and chemoselective functionalization of carbohydrates is explored. Chiral NHCs allow for the highly regioselective oxidative esterification of various carbohydrates using aldehydes as acylation precursors. The transformation was also shown to be amenable to both cis/trans diol isomers, free amino groups, and selective for specific sugar epimers in competition experiments. Efficiency and regioselectivity of the acylation can be improved upon using two different NHC catalysts that act cooperatively. The potential of the method is documented by the regioselective acylation of an amino-linked neodisaccharide. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Toward Green Acylation of (Heteroarenes: Palladium-Catalyzed Carbonylation of Olefins to Ketones

Directory of Open Access Journals (Sweden)

Jie Liu

2017-11-01

Full Text Available Green Friedel–Crafts acylation reactions belong to the most desired transformations in organic chemistry. The resulting ketones constitute important intermediates, building blocks, and functional molecules in organic synthesis as well as for the chemical industry. Over the past 60 years, advances in this topic have focused on how to make this reaction more economically and environmentally friendly by using green acylating conditions, such as stoichiometric acylations and catalytic homogeneous and heterogeneous acylations. However, currently well-established methodologies for their synthesis either produce significant amounts of waste or proceed under harsh conditions, limiting applications. Here, we present a new protocol for the straightforward and selective introduction of acyl groups into (hetero­arenes without directing groups by using available olefins with inexpensive CO. In the presence of commercial palladium catalysts, inter- and intramolecular carbonylative C–H functionalizations take place with good regio- and chemoselectivity. Compared to classical Friedel–Crafts chemistry, this novel methodology proceeds under mild reaction conditions. The general applicability of this methodology is demonstrated by the direct carbonylation of industrial feedstocks (ethylene and diisobutene as well as of natural products (eugenol and safrole. Furthermore, synthetic applications to drug molecules are showcased.

Acute aerobic exercise differentially alters acylated ghrelin and perceived fullness in normal-weight and obese individuals.

Science.gov (United States)

Heden, Timothy D; Liu, Ying; Park, Youngmin; Dellsperger, Kevin C; Kanaley, Jill A

2013-09-01

Adiposity alters acylated ghrelin concentrations, but it is unknown whether adiposity alters the effect of exercise and feeding on acylated ghrelin responses. Therefore, the purpose of this study was to determine whether adiposity [normal-weight (NW) vs. obese (Ob)] influences the effect of exercise and feeding on acylated ghrelin, hunger, and fullness. Fourteen NW and 14 Ob individuals completed two trials in a randomized counterbalanced fashion, including a prior exercise trial (EX) and a no exercise trial (NoEX). During the EX trial, the participants performed 1 h of treadmill walking (55-60% peak O2 uptake) during the evening, 12 h before a 4-h standardized mixed meal test. Frequent blood samples were taken and analyzed for acylated ghrelin, and a visual analog scale was used to assess perceived hunger and fullness. In NW individuals, EX, compared with NoEX, reduced fasting acylated ghrelin concentrations by 18% (P = 0.03), and, in response to feeding, the change in acylated ghrelin (P = 0.02) was attenuated by 39%, but perceived hunger and fullness were unaltered. In Ob individuals, despite no changes in fasting or postprandial acylated ghrelin concentrations with EX, postprandial fullness was attenuated by 46% compared with NoEX (P = 0.05). In summary, exercise performed the night before a meal suppresses acylated ghrelin concentrations in NW individuals without altering perceived hunger or fullness. In Ob individuals, despite no changes in acylated ghrelin concentrations, EX reduced the fullness response to the test meal. Acylated ghrelin and perceived fullness responses are differently altered by acute aerobic exercise in NW and Ob individuals.

Intestinal short chain fatty acids and their link with diet and human health

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David eRios-Covian

2016-02-01

Full Text Available The colon is inhabited by a dense population of microorganisms, the so-called gut microbiota, able to ferment carbohydrates and proteins that escape absorption in the small intestine during digestion. This microbiota produces a wide range of metabolites, including short chain fatty acids (SCFA. These compounds are absorbed in the large bowel and are defined as 1-6 carbon volatile fatty acids which can present straight or branched-chain conformation. Their production is influenced by the pattern of food intake and diet-mediated changes in the gut microbiota. SCFA have distinct physiological effects: they contribute to shaping the gut environment, influence the physiology of the colon, they can be used as energy sources by host cells and the intestinal microbiota and they also participate in different host-signalling mechanisms. We summarize the current knowledge about the production of SCFA, including bacterial cross-feedings interactions, and the biological properties of these metabolites with impact on the human health

Room-Temperature Alternative to the Arbuzov Reaction: The Reductive Deoxygenation of Acyl Phosphonates

OpenAIRE

Kedrowski, Sean M. A.; Dougherty, Dennis A.

2010-01-01

The reductive deoxygenation of acyl phosphonates using a Wolff−Kishner-like sequence is described. This transformation allows direct access to alkyl phosphonates from acyl phosphonates at room temperature. The method can be combined with acyl phosphonate synthesis into a one pot, four-step procedure for the conversion of carboxylic acids into alkyl phosphonates. The methodology works well for a variety of aliphatic acids and shows a functional group tolerance similar to that of other hydrazon...

Structure of a short-chain dehydrogenase/reductase (SDR) within a genomic island from a clinical strain of Acinetobacter baumannii

Energy Technology Data Exchange (ETDEWEB)

Shah, Bhumika S., E-mail: bhumika.shah@mq.edu.au; Tetu, Sasha G. [Macquarie University, Research Park Drive, Sydney, NSW 2109 (Australia); Harrop, Stephen J. [University of New South Wales, Sydney, NSW 2052 (Australia); Paulsen, Ian T.; Mabbutt, Bridget C. [Macquarie University, Research Park Drive, Sydney, NSW 2109 (Australia)

2014-09-25

The structure of a short-chain dehydrogenase encoded within genomic islands of A. baumannii strains has been solved to 2.4 Å resolution. This classical SDR incorporates a flexible helical subdomain. The NADP-binding site and catalytic side chains are identified. Over 15% of the genome of an Australian clinical isolate of Acinetobacter baumannii occurs within genomic islands. An uncharacterized protein encoded within one island feature common to this and other International Clone II strains has been studied by X-ray crystallography. The 2.4 Å resolution structure of SDR-WM99c reveals it to be a new member of the classical short-chain dehydrogenase/reductase (SDR) superfamily. The enzyme contains a nucleotide-binding domain and, like many other SDRs, is tetrameric in form. The active site contains a catalytic tetrad (Asn117, Ser146, Tyr159 and Lys163) and water molecules occupying the presumed NADP cofactor-binding pocket. An adjacent cleft is capped by a relatively mobile helical subdomain, which is well positioned to control substrate access.

Structure of a short-chain dehydrogenase/reductase (SDR) within a genomic island from a clinical strain of Acinetobacter baumannii

International Nuclear Information System (INIS)

Shah, Bhumika S.; Tetu, Sasha G.; Harrop, Stephen J.; Paulsen, Ian T.; Mabbutt, Bridget C.

2014-01-01

The structure of a short-chain dehydrogenase encoded within genomic islands of A. baumannii strains has been solved to 2.4 Å resolution. This classical SDR incorporates a flexible helical subdomain. The NADP-binding site and catalytic side chains are identified. Over 15% of the genome of an Australian clinical isolate of Acinetobacter baumannii occurs within genomic islands. An uncharacterized protein encoded within one island feature common to this and other International Clone II strains has been studied by X-ray crystallography. The 2.4 Å resolution structure of SDR-WM99c reveals it to be a new member of the classical short-chain dehydrogenase/reductase (SDR) superfamily. The enzyme contains a nucleotide-binding domain and, like many other SDRs, is tetrameric in form. The active site contains a catalytic tetrad (Asn117, Ser146, Tyr159 and Lys163) and water molecules occupying the presumed NADP cofactor-binding pocket. An adjacent cleft is capped by a relatively mobile helical subdomain, which is well positioned to control substrate access

Studies on acylation of lysolecithin in chicken intestine

International Nuclear Information System (INIS)

Lokesh, B.R.; Madhava Rao, A.; Murthy, S.K.

1976-01-01

The enzymatic acylation of lysolecithin to lecithin is shown to occur in the brush border-free particulate fraction of the small intestines of neonatal chicken. It requires ATP, coenzyme A and Mg 2+ or Mn 2+ for maximal activity. The system is specific for oleic acid. The fatty acid composition at the α-position of lysolecithin does not seem to influence the rate of acylation. The fatty acid incorporated into lysolecithin is shown to occupy exclusively, the β-position. [ 32 P]lecithin and [1- 14 C]oleic acid has been used as tracers in the studies. (author)

Quantum chemical study of penicillin: Reactions after acylation

Science.gov (United States)

Li, Rui; Feng, Dacheng; Zhu, Feng

The density functional theory methods were used on the model molecules of penicillin to determine the possible reactions after their acylation on ?-lactamase, and the results were compared with sulbactam we have studied. The results show that, the acylated-enzyme tetrahedral intermediate can evolves with opening of ?-lactam ring as well as the thiazole ring; the thiazole ring-open products may be formed via ?-lactam ring-open product or from tetrahedral intermediate directly. Those products, in imine or enamine form, can tautomerize via hydrogen migration. In virtue of the water-assisted, their energy barriers are obviously reduced.

Insights into early extracellular matrix evolution: spongin short chain collagen-related proteins are homologous to basement membrane type IV collagens and form a novel family widely distributed in invertebrates.

Science.gov (United States)

Aouacheria, Abdel; Geourjon, Christophe; Aghajari, Nushin; Navratil, Vincent; Deléage, Gilbert; Lethias, Claire; Exposito, Jean-Yves

2006-12-01

Collagens are thought to represent one of the most important molecular innovations in the metazoan line. Basement membrane type IV collagen is present in all Eumetazoa and was found in Homoscleromorpha, a sponge group with a well-organized epithelium, which may represent the first stage of tissue differentiation during animal evolution. In contrast, spongin seems to be a demosponge-specific collagenous protein, which can totally substitute an inorganic skeleton, such as in the well-known bath sponge. In the freshwater sponge Ephydatia mülleri, we previously characterized a family of short-chain collagens that are likely to be main components of spongins. Using a combination of sequence- and structure-based methods, we present evidence of remote homology between the carboxyl-terminal noncollagenous NC1 domain of spongin short-chain collagens and type IV collagen. Unexpectedly, spongin short-chain collagen-related proteins were retrieved in nonsponge animals, suggesting that a family related to spongin constitutes an evolutionary sister to the type IV collagen family. Formation of the ancestral NC1 domain and divergence of the spongin short-chain collagen-related and type IV collagen families may have occurred before the parazoan-eumetazoan split, the earliest divergence among extant animal phyla. Molecular phylogenetics based on NC1 domain sequences suggest distinct evolutionary histories for spongin short-chain collagen-related and type IV collagen families that include spongin short-chain collagen-related gene loss in the ancestors of Ecdyzosoa and of vertebrates. The fact that a majority of invertebrates encodes spongin short-chain collagen-related proteins raises the important question to the possible function of its members. Considering the importance of collagens for animal structure and substratum attachment, both families may have played crucial roles in animal diversification.

Dietary Caprylic Acid (C8:0) Does Not Increase Plasma Acylated Ghrelin but Decreases Plasma Unacylated Ghrelin in the Rat

Science.gov (United States)

Lemarié, Fanny; Beauchamp, Erwan; Dayot, Stéphanie; Duby, Cécile; Legrand, Philippe; Rioux, Vincent

2015-01-01

Focusing on the caprylic acid (C8:0), this study aimed at investigating the discrepancy between the formerly described beneficial effects of dietary medium chain fatty acids on body weight loss and the C8:0 newly reported effect on food intake via ghrelin octanoylation. During 6 weeks, Sprague-Dawley male rats were fed with three dietary C8:0 levels (0, 8 and 21% of fatty acids) in three experimental conditions (moderate fat, caloric restriction and high fat). A specific dose-response enrichment of the stomach tissue C8:0 was observed as a function of dietary C8:0, supporting the hypothesis of an early preduodenal hydrolysis of medium chain triglycerides and a direct absorption at the gastric level. However, the octanoylated ghrelin concentration in the plasma was unchanged in spite of the increased C8:0 availability. A reproducible decrease in the plasma concentration of unacylated ghrelin was observed, which was consistent with a decrease in the stomach preproghrelin mRNA and stomach ghrelin expression. The concomitant decrease of the plasma unacylated ghrelin and the stability of its acylated form resulted in a significant increase in the acylated/total ghrelin ratio which had no effect on body weight gain or total dietary consumption. This enhanced ratio measured in rats consuming C8:0 was however suspected to increase (i) growth hormone (GH) secretion as an increase in the GH-dependent mRNA expression of the insulin like growth Factor 1 (IGF-1) was measured (ii) adipocyte diameters in subcutaneous adipose tissue without an increase in the fat pad mass. Altogether, these results show that daily feeding with diets containing C8:0 increased the C8:0 level in the stomach more than all the other tissues, affecting the acylated/total ghrelin plasma ratio by decreasing the concentration of circulating unacylated ghrelin. However, these modifications were not associated with increased body weight or food consumption. PMID:26196391

Social-economic and environmental sustainability of short supply chains: opportunities for development rural territories

Directory of Open Access Journals (Sweden)

Mykola Babych

2018-03-01

Full Text Available The paper substantiates the expediency of developing short supply chains at the local level. The focus of this paper is to determine opportunities for developing rural territories in Ukraine on the basis of the development of short supply chains in terms of ensuring social, economic and environmental sustainability. It is established that such an approach provides stability of development of rural territory, in particular, it promotes: social interaction (trust, justice, solidarity and common values between consumers and producers, community development (just relationships, pride, social cohesion and community affiliation, strengthening local culture and identity, health and well-being of the population (healthy diet; access to healthy food, health improvement, which ensures social sustainability of the system; rural development and economic recovery (increase of workplaces, tourism development, increase of local incomes, development of small and medium-sized farms, achievement of economic benefits to farms (reduction of overheads, fixed margin and premium for quality, increase of competitiveness and economic viability, sustainable use resources, which ensures economic stability of the system; reducing energy consumption and carbon dioxide emissions (reducing transport and storage time; using alternative technologies; maximizing manual labor; reducing the use of plastic packaging; reducing food losses; sustainability of agro-systems (promoting agro-biodiversity; using local varieties; highlighting ecological and organic production, which ensures the ecological stability of the system.

Cis–Trans Configuration of Coumaric Acid Acylation Affects the Spectral and Colorimetric Properties of Anthocyanins

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Gregory T. Sigurdson

2018-03-01

Full Text Available The color expression of anthocyanins can be affected by a variety of environmental factors and structural characteristics. Anthocyanin acylation (type and number of acids is known to be key, but the influence of acyl isomers (with unique stereochemistries remains to be explored. The objective of this study was to investigate the effects of cis–trans configuration of the acylating group on the spectral and colorimetric properties of anthocyanins. Petunidin-3-rutinoside-5-glucoside (Pt-3-rut-5-glu and Delphinidin-3-rutinoside-5-glucoside (Dp-3-rut-5-glu and their cis and trans coumaroylated derivatives were isolated from black goji and eggplant, diluted in pH 1–9 buffers, and analyzed spectrophotometrically (380–700 nm and colorimetrically (CIELAB during 72 h of storage (25 °C, dark. The stereochemistry of the acylating group strongly impacted the spectra, color, and stability of the Dp and Pt anthocyanins. Cis acylated pigments exhibited the greatest λmax in all pH, as much as 66 nm greater than their trans counterparts, showing bluer hues. Cis acylation seemed to reduce hydration across pH, increasing color intensity, while trans acylation generally improved color retention over time. Dp-3-cis-p-cou-rut-5-glu exhibited blue hues even in pH 5 (C*ab = 10, hab = 256° where anthocyanins are typically colorless. Cis or trans double bond configurations of the acylating group affected anthocyanin spectral and stability properties.

Protein Misfolding and Human Disease

DEFF Research Database (Denmark)

Gregersen, Niels; Bross, Peter Gerd; Vang, Søren

2006-01-01

phenylketonuria, Parkinson's disease, α-1-antitrypsin deficiency, familial neurohypophyseal diabetes insipidus, and short-chain acyl-CoA dehydrogenase deficiency. Despite the differences, an emerging paradigm suggests that the cellular effects of protein misfolding provide a common framework that may contribute...

Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis*

OpenAIRE

Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

2016-01-01

Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction wi...

Cost-effectiveness analysis of universal newborn screening for medium chain acyl-CoA dehydrogenase deficiency in France

Directory of Open Access Journals (Sweden)

Hamers Françoise F

2012-06-01

Full Text Available Abstract Background Five diseases are currently screened on dried blood spots in France through the national newborn screening programme. Tandem mass spectrometry (MS/MS is a technology that is increasingly used to screen newborns for an increasing number of hereditary metabolic diseases. Medium chain acyl-CoA dehydrogenase deficiency (MCADD is among these diseases. We sought to evaluate the cost-effectiveness of introducing MCADD screening in France. Methods We developed a decision model to evaluate, from a societal perspective and a lifetime horizon, the cost-effectiveness of expanding the French newborn screening programme to include MCADD. Published and, where available, routine data sources were used. Both costs and health consequences were discounted at an annual rate of 4%. The model was applied to a French birth cohort. One-way sensitivity analyses and worst-case scenario simulation were performed. Results We estimate that MCADD newborn screening in France would prevent each year five deaths and the occurrence of neurological sequelae in two children under 5 years, resulting in a gain of 128 life years or 138 quality-adjusted life years (QALY. The incremental cost per year is estimated at €2.5 million, down to €1 million if this expansion is combined with a replacement of the technology currently used for phenylketonuria screening by MS/MS. The resulting incremental cost-effectiveness ratio (ICER is estimated at €7 580/QALY. Sensitivity analyses indicate that while the results are robust to variations in the parameters, the model is most sensitive to the cost of neurological sequelae, MCADD prevalence, screening effectiveness and screening test cost. The worst-case scenario suggests an ICER of €72 000/QALY gained. Conclusions Although France has not defined any threshold for judging whether the implementation of a health intervention is an efficient allocation of public resources, we conclude that the expansion of the French

Decreased ghrelin and des-acyl ghrelin plasma levels in patients affected by pharmacoresistant epilepsy and maintained on the ketogenic diet.

Science.gov (United States)

Marchiò, Maddalena; Roli, Laura; Giordano, Carmela; Trenti, Tommaso; Guerra, Azzurra; Biagini, Giuseppe

2018-03-23

The gastric hormones ghrelin and des-acyl ghrelin have been found to be altered in patients treated with antiepileptic drugs. However, it is unknown if these hormones could be modified by other antiepileptic treatments, such as the ketogenic diet. Especially, a reduction in ghrelin levels could be relevant in view of the growth retardation observed under ketogenic diet treatment. For this reason we aimed to determine the changes in ghrelin and des-acyl ghrelin plasma levels in children affected by refractory epilepsy and treated with the ketogenic diet up to 90 days. Both peptides were measured by immunoassays in plasma obtained from 16 children. Ghrelin plasma levels were progressively reduced by the ketogenic diet, reaching a minimum corresponding to 42% of basal levels after 90 days of ketogenic diet (P ketogenic diet (P ketogenic diet administration. Ghrelin and des-acyl ghrelin are downregulated by the ketogenic diet in children affected by refractory epilepsy. Although no significant changes in growth were observed during the short time period of our investigation, the reduction in ghrelin availability may explain the reported growth retardation found in children treated with the ketogenic diet in the long-term. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Rapid Quantification of Low-Viscosity Acetyl-Triacylglycerols Using Electrospray Ionization Mass Spectrometry.

Science.gov (United States)

Bansal, Sunil; Durrett, Timothy P

2016-09-01

Acetyl-triacylglycerols (acetyl-TAG) possess an sn-3 acetate group, which confers useful chemical and physical properties to these unusual triacylglycerols (TAG). Current methods for quantification of acetyl-TAG are time consuming and do not provide any information on the molecular species profile. Electrospray ionization mass spectrometry (ESI-MS)-based methods can overcome these drawbacks. However, the ESI-MS signal intensity for TAG depends on the aliphatic chain length and unsaturation index of the molecule. Therefore response factors for different molecular species need to be determined before any quantification. The effects of the chain length and the number of double-bonds of the sn-1/2 acyl groups on the signal intensity for the neutral loss of short chain length sn-3 groups were quantified using a series of synthesized sn-3 specific structured TAG. The signal intensity for the neutral loss of the sn-3 acyl group was found to negatively correlated with the aliphatic chain length and unsaturation index of the sn-1/2 acyl groups. The signal intensity of the neutral loss of the sn-3 acyl group was also negatively correlated with the size of that chain. Further, the position of the group undergoing neutral loss was also important, with the signal from an sn-2 acyl group much lower than that from one located at sn-3. Response factors obtained from these analyses were used to develop a method for the absolute quantification of acetyl-TAG. The increased sensitivity of this ESI-MS-based approach allowed successful quantification of acetyl-TAG in various biological settings, including the products of in vitro enzyme activity assays.

Bioaccumulation and biomagnification of short and medium chain polychlorinated paraffins in different species of fish from Liaodong Bay, North China

OpenAIRE

Huang, Huiting; Gao, Lirong; Xia, Dan; Qiao, Lin

2017-01-01

Chlorinated paraffins (CPs) are highly complex technical mixtures, and the short chain chlorinated paraffins (SCCPs) are classed as persistent and have been included in the Stockholm Convention. However, there have been few studies of SCCPs and medium chain chlorinated paraffins (MCCPs) and their bioaccumulation and biomagnification in different species of fish. The present study investigated the levels, congener group profiles, bioaccumulation, and biomagnification of SCCPs and MCCPs in diff...

Short Chain Fatty Acids in the Colon and Peripheral Tissues: A Focus on Butyrate, Colon Cancer, Obesity and Insulin Resistance

Directory of Open Access Journals (Sweden)

Sean M. McNabney

2017-12-01

Full Text Available Increased dietary fiber consumption has been associated with many beneficial effects, including amelioration of obesity and insulin resistance. These effects may be due to the increased production of short chain fatty acids, including propionate, acetate and butyrate, during fermentation of the dietary fiber in the colon. Indeed, oral and dietary supplementation of butyrate alone has been shown to prevent high fat-diet induced obesity and insulin resistance. This review focuses on sources of short chain fatty acids, with emphasis on sources of butyrate, mechanisms of fiber and butyrate metabolism in the gut and its protective effects on colon cancer and the peripheral effects of butyrate supplementation in peripheral tissues in the prevention and reversal of obesity and insulin resistance.

Configurational and constitutional information storage: multiple dynamics in systems based on pyridyl and acyl hydrazones.

Science.gov (United States)

Chaur, Manuel N; Collado, Daniel; Lehn, Jean-Marie

2011-01-03

The C=N group of hydrazones can undergo E/Z isomerization both photochemically and thermally, allowing the generation of a closed process that can be tuned by either of these two physical stimuli. On the other hand, hydrazine-exchange reactions enable a constitutional change in a given hydrazone. The two classes of processes: 1) configurational (physically stimulated) and 2) constitutional (chemically stimulated) give access to short-term and long-term information storage, respectively. Such transformations are reported herein for two hydrazones (bis-pyridyl hydrazone and 2-pyridinecarboxaldehyde phenylhydrazone) that undergo a closed, chemically or physically driven process, and, in addition, can be locked or unlocked at will by metal-ion coordination or removal. These features also extend to acyl hydrazones derived from 2-pyridinecarboxaldehyde. Similarly to the terpydine-like hydrazones, such acyl hydrazones can undergo both constitutional and configurational changes, as well as metal-ion coordination. All these types of hydrazones represent dynamic systems capable of acting as multiple state molecular devices, in which the presence of coordination sites furthermore allows the metal ion-controlled locking and unlocking of the interconversion of the different states. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of medium-chain length capsinoids from coconut oil catalyzed by Candida rugosa lipases.

Science.gov (United States)

Trbojević Ivić, Jovana; Milosavić, Nenad; Dimitrijević, Aleksandra; Gavrović Jankulović, Marija; Bezbradica, Dejan; Kolarski, Dušan; Veličković, Dušan

2017-03-01

A commercial preparation of Candida rugosa lipases (CRL) was tested for the production of capsinoids by esterification of vanillyl alcohol (VA) with free fatty acids (FA) and coconut oil (CO) as acyl donors. Screening of FA chain length indicated that C8-C12 FA (the most common FA found in CO triglycerides) are the best acyl-donors, yielding 80-85% of their specific capsinoids. Hence, when CO, which is rich in these FA, was used as the substrate, a mixture of capsinoids (vanillyl caprylate, vanillyl decanoate and vanillyl laurate) was obtained. The findings presented here suggest that our experimental method can be applied for the enrichment of CO with capsinoids, thus giving it additional health promoting properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification and Funtional Characterization of Three Postsynaptic Short-chain Neurotoxins from Hydrophiinae, Lapemis hardwickii Gray.

Science.gov (United States)

Zhong, Xiao-Fen; Peng, Li-Sheng; Wu, Wen-Yan; Wei, Jian-Wen; Yang, Hong; Yang, Yan-Zhen; Xu, An-Long

2001-01-01

Three cDNA clones, sn12, sn36 and sn160, encoding isoforms of postsynaptic short-chain neurotoxins, were cloned by screening a cDNA library of the venom from Hydrophiinae, Lapemis hardwickii Gray. The sequences of three cDNA clones encoded proteins consisting of 60 amino acid residues. There was only one amino acid substitution among the three isoforms SN12, SN36 and SN160 at the position 46 of mature proteins, and they were Pro(46), His(46) and Arg(46), respectively. The three molecules were expressed in Escherichia coli and the recombinant proteins were characterized. Different LD(50) were obtained, namely 0.0956 mg/kg, 0.3467 mg/kg and 0.2192 mg/kg, when the SN12, SN36 and SN160 were injected into Kunming mice(i.p.). In analgesic effect assayed by the acetic acid-induced writhing method, SN12 and SN160 showed similar analgesic effect, but SN36 had effects significantly different with the other two. Our studies suggested that the amino acid residues on position 46 could affect the combination between the postsynaptic short-chain neurotoxins and the nicotinic acetylchoine receptor, since different amino acid substitution resulted in different biological activities.

Effects of ghrelin and des-acyl ghrelin on neurogenesis of the rat fetal spinal cord

International Nuclear Information System (INIS)

Sato, Miho; Nakahara, Keiko; Goto, Shintaro; Kaiya, Hiroyuki; Miyazato, Mikiya; Date, Yukari; Nakazato, Masamitsu; Kangawa, Kenji; Murakami, Noboru

2006-01-01

Expressions of the growth hormone secretagogue receptor (GHS-R) mRNA and its protein were confirmed in rat fetal spinal cord tissues by RT-PCR and immunohistochemistry. In vitro, over 3 nM ghrelin and des-acyl ghrelin induced significant proliferation of primary cultured cells from the fetal spinal cord. The proliferating cells were then double-stained using antibodies against the neuronal precursor marker, nestin, and the cell proliferation marker, 5-bromo-2'-deoxyuridine (BrdU), and the nestin-positive cells were also found to be co-stained with antibody against GHS-R. Furthermore, binding studies using [ 125 I]des-acyl ghrelin indicated the presence of a specific binding site for des-acyl ghrelin, and confirmed that the binding was displaced with unlabeled des-acyl ghrelin or ghrelin. These results indicate that ghrelin and des-acyl ghrelin induce proliferation of neuronal precursor cells that is both dependent and independent of GHS-R, suggesting that both ghrelin and des-acyl ghrelin are involved in neurogenesis of the fetal spinal cord

Acyl Meldrum's acid derivatives: application in organic synthesis

International Nuclear Information System (INIS)

Janikowska, K; Rachoń, J; Makowiec, S

2014-01-01

This review is focused on an important class of Meldrum's acid derivatives commonly known as acyl Meldrum's acids. The preparation methods of these compounds are considered including the recently proposed and rather rarely used ones. The chemical properties of acyl Meldrum's acids are described in detail, including thermal stability and reactions with various nucleophiles. The possible mechanisms of these transformations are analyzed. The bibliography includes 134 references

Acylation Enhances, but Is Not Required for, the Cytotoxic Activity of Mannheimia haemolytica Leukotoxin in Bighorn Sheep.

Science.gov (United States)

Batra, Sai A; Shanthalingam, Sudarvili; Munske, Gerhard R; Raghavan, Bindu; Kugadas, Abirami; Bavanthasivam, Jegarubee; Highlander, Sarah K; Srikumaran, Subramaniam

2015-10-01

Mannheimia haemolytica causes pneumonia in domestic and wild ruminants. Leukotoxin (Lkt) is the most important virulence factor of the bacterium. It is encoded within the four-gene lktCABD operon: lktA encodes the structural protoxin, and lktC encodes a trans-acylase that adds fatty acid chains to internal lysine residues in the protoxin, which is then secreted from the cell by a type 1 secretion system apparatus encoded by lktB and lktD. It has been reported that LktC-mediated acylation is necessary for the biological effects of the toxin. However, an LktC mutant that we developed previously was only partially attenuated in its virulence for cattle. The objective of this study was to elucidate the role of LktC-mediated acylation in Lkt-induced cytotoxicity. We performed this study in bighorn sheep (Ovis canadensis) (BHS), since they are highly susceptible to M. haemolytica infection. The LktC mutant caused fatal pneumonia in 40% of inoculated BHS. On necropsy, a large number of necrotic polymorphonuclear leukocytes (PMNs) were observed in the lungs. Lkt from the mutant was cytotoxic to BHS PMNs in an in vitro cytotoxicity assay. Flow cytometric analysis of mutant Lkt-treated PMNs revealed the induction of necrosis. Scanning electron microscopic analysis revealed the presence of pores and blebs on mutant-Lkt-treated PMNs. Mass spectrometric analysis confirmed that the mutant secreted an unacylated Lkt. Taken together, these results suggest that acylation is not necessary for the cytotoxic activity of M. haemolytica Lkt but that it enhances the potency of the toxin. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Short chain molecular junctions: Charge transport versus dipole moment

International Nuclear Information System (INIS)

Ikram, I. Mohamed; Rabinal, M.K.

2015-01-01

Graphical abstract: - Highlights: • The role of dipole moment of organic molecules on molecular junctions has been studied. • Molecular junctions constituted using propargyl molecules of different dipole moments. • The electronic properties of the molecules were calculated using Gaussian software. • Junctions show varying rectification due to their varying dipole moment and orientation. - Abstract: The investigation of the influence of dipole moment of short chain organic molecules having three carbon atoms varying in end group on silicon surface was carried on. Here, we use three different molecules of propargyl series varying in dipole moment and its orientation to constitute molecular junctions. The charge transport mechanism in metal–molecules–semiconductor (MMS) junction obtained from current–voltage (I–V) characteristics shows the rectification behavior for two junctions whereas the other junction shows a weak rectification. The electronic properties of the molecules were calculated using Gaussian software package. The observed rectification behavior of these junctions is examined and found to be accounted to the orientation of dipole moment and electron cloud density distribution inside the molecules

Two very long chain fatty acid acyl-CoA synthetase genes, acs-20 and acs-22, have roles in the cuticle surface barrier in Caenorhabditis elegans.

Directory of Open Access Journals (Sweden)

Eriko Kage-Nakadai

Full Text Available In multicellular organisms, the surface barrier is essential for maintaining the internal environment. In mammals, the barrier is the stratum corneum. Fatty acid transport protein 4 (FATP4 is a key factor involved in forming the stratum corneum barrier. Mice lacking Fatp4 display early neonatal lethality with features such as tight, thick, and shiny skin, and a defective skin barrier. These symptoms are strikingly similar to those of a human skin disease called restrictive dermopathy. FATP4 is a member of the FATP family that possesses acyl-CoA synthetase activity for very long chain fatty acids. How Fatp4 contributes to skin barrier function, however, remains to be elucidated. In the present study, we characterized two Caenorhabditis elegans genes, acs-20 and acs-22, that are homologous to mammalian FATPs. Animals with mutant acs-20 exhibited defects in the cuticle barrier, which normally prevents the penetration of small molecules. acs-20 mutant animals also exhibited abnormalities in the cuticle structure, but not in epidermal cell fate or cell integrity. The acs-22 mutants rarely showed a barrier defect, whereas acs-20;acs-22 double mutants had severely disrupted barrier function. Moreover, the barrier defects of acs-20 and acs-20;acs-22 mutants were rescued by acs-20, acs-22, or human Fatp4 transgenes. We further demonstrated that the incorporation of exogenous very long chain fatty acids into sphingomyelin was reduced in acs-20 and acs-22 mutants. These findings indicate that C. elegans Fatp4 homologue(s have a crucial role in the surface barrier function and this model might be useful for studying the fundamental molecular mechanisms underlying human skin barrier and relevant diseases.

Short supply chain: analysis of the competitiveness of organic horticultural farmers at Italian regional level

OpenAIRE

Bertazzoli, Aldo; Ruggeri, Arianna; Samoggia, Antonella

2010-01-01

The paper focuses on the competitiveness of organic horticultural farms implementing short food supply chain (SFSC), by analysing the organisational structures adopted by farmers and their economic performance. The collection of data based on face to face interviews with farmers and the review of the rural development plans of three central Italy regions. Results show that farms prefer a combination of organizational structures that involve both business to consumer and business to business s...

Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

Science.gov (United States)

Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

2016-01-01

The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The importance of stakeholder-initiatives for business models in short food supply chains: the case of the Netherlands

NARCIS (Netherlands)

Wubben, E.F.M.; Fondse, M.; Pascucci, S.

2013-01-01

While the interest in Short Food Supply Chains (SFSCs) is growing, we still await management studies that explore the impact of stakeholders of SFSCs in substantial numbers. This article investigates the differences in the business models of SFSCs that may be attributed to the initiator-stakeholder,

Des-acyl ghrelin prevents heatstroke-like symptoms in rats exposed to high temperature and high humidity.

Science.gov (United States)

Inoue, Yoshiyuki; Hayashi, Yujiro; Kangawa, Kenji; Suzuki, Yoshihiro; Murakami, Noboru; Nakahara, Keiko

2016-02-26

We have shown previously that des-acyl ghrelin decreases body temperature in rats through activation of the parasympathetic nervous system. Here we investigated whether des-acyl ghrelin ameliorates heatstroke in rats exposed to high temperature. Peripheral administration of des-acyl ghrelin significantly attenuated hyperthermia induced by exposure to high-temperature (35°C) together with high humidity (70-80%). Although biochemical analysis revealed that exposure to high temperature significantly increased hematocrit and the serum levels of aspartate amino transferase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), creatinine and electrolytes (Na(+), K(+), Cl(-)), most of these heatstroke-associated reactions were significantly reduced by treatment with des-acyl ghrelin. The level of des-acyl ghrelin in plasma was also found to be significantly increased under high-temperature conditions. These results suggest that des-acyl ghrelin could be useful for preventing heatstroke under high temperature condition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Acylated flavonol glycosides from Larix needles

NARCIS (Netherlands)

Niemann, Gerard J.

2006-01-01

Kaempferol-3-p-coumarylglucoside (KCG) was isolated from ether fractions of acetone-extracted freeze-dried needles of all larch species investigated. In each case, KCG was found as one of the main flavonoids, whereas often a variety of closely related, acylated flavonoids was present in either

Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica.

Science.gov (United States)

Li, Huijuan; Fu, Jianjie; Zhang, Aiqian; Zhang, Qinghua; Wang, Yawei

2016-09-01

As a candidate persistent organic pollutant of the Stockholm Convention, short-chain chlorinated paraffins (SCCPs) have recently received particular attention. In this study, we investigated, for the first time, the concentrations of SCCPs in biota samples collected from the Fildes Peninsula at King George Island and Ardley Island, Antarctica. The concentrations of SCCPs ranged from 3.5 to 256.6ng/g (dry weight, dw), with a mean of 76.6±61.8ng/g dw, which was lower than those detected in mid- and low-latitude regions. The long-range transport behaviour of SCCPs was confirmed by both the detection of SCCPs in Antarctic remote areas and their special congener profiles. Short carbon chain (C10) congeners predominated in the Antarctic samples, which accounted for 56.1% of the total SCCP contamination. Such enrichment of C10 congeners indicated the high potential for the long-range transport of shorter chain congeners. In addition, SCCPs tended to be enriched in the species with high lipid contents. The biomagnification potential of SCCPs was found between Archeogastropoda (Agas) and Neogastropoda (Ngas), and the biomagnification factors of shorter chain congeners of SCCPs were higher than that of the longer chain ones. Considering that the endemic species in polar regions may be sensitive and vulnerable to the adverse effects of environmental contaminants, more attention should be paid on the bioaccumulation and toxicological risks of SCCPs in polar environments. Copyright © 2016. Published by Elsevier Ltd.

Long-term physical ageing in As-Se glasses with short chalcogen chains

International Nuclear Information System (INIS)

Golovchak, R; Shpotyuk, O; Kozdras, A; Vlcek, M; Bureau, B; Kovalskiy, A; Jain, H

2008-01-01

Long-term physical ageing of chalcogenide glasses, which occurs over tens of years, is much less understood than the short-term ageing. With Se-rich underconstrained As 30 Se 70 glass as a model composition (consisting of Se n chains with n≤3 on average), a microscopic model is developed for this phenomenon by combining information from differential scanning calorimetry, extended x-ray absorption fine structure, Raman, and 77 Se solid state nuclear magnetic resonance spectroscopies. The accompanying changes in the electronic structure of these glasses are investigated by x-ray photoelectron spectroscopy. The data suggest ageing from cooperative relaxation, presumably involving bond switching or reconfiguration of As-Se-Se-As fragments

Long-term physical ageing in As-Se glasses with short chalcogen chains

Energy Technology Data Exchange (ETDEWEB)

Golovchak, R; Shpotyuk, O [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska street, Lviv, UA-79031 (Ukraine); Kozdras, A [Faculty of Physics of Opole University of Technology, 75, Ozimska street, Opole, 45370 (Poland); Vlcek, M [Department of General and Inorganic Chemistry, Faculty of Chemistry, University of Pardubice, 532 10 Pardubice (Czech Republic); Bureau, B [Verres et Ceramiques, UMR CNRS 6226 Sciences Chimiques de Rennes, University of Rennes, 1, Campus de Beaulieu, Rennes, 35042 (France); Kovalskiy, A; Jain, H [Department of Materials Science and Engineering, Lehigh University, 5, East Packer Avenue, Bethlehem, PA 18015-3195 (United States)

2008-06-18

Long-term physical ageing of chalcogenide glasses, which occurs over tens of years, is much less understood than the short-term ageing. With Se-rich underconstrained As{sub 30}Se{sub 70} glass as a model composition (consisting of Se{sub n} chains with n{<=}3 on average), a microscopic model is developed for this phenomenon by combining information from differential scanning calorimetry, extended x-ray absorption fine structure, Raman, and {sup 77}Se solid state nuclear magnetic resonance spectroscopies. The accompanying changes in the electronic structure of these glasses are investigated by x-ray photoelectron spectroscopy. The data suggest ageing from cooperative relaxation, presumably involving bond switching or reconfiguration of As-Se-Se-As fragments.

A simple, effective, green method for regioselective 3-acylation of unprotected indoles

DEFF Research Database (Denmark)

Tran, Phuong Huong; Tran, Hai N.; Hansen, Poul Erik

2015-01-01

A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)3 in catalytic amounts is found...

Elevated levels of short carbon-chain PFCAs in breast milk among Korean women: Current status and potential challenges.

Science.gov (United States)

Kang, Habyeong; Choi, Kyungho; Lee, Haeng-Shin; Kim, Do-Hee; Park, Na-Youn; Kim, Sunmi; Kho, Younglim

2016-07-01

Breast milks can be contaminated with perfluoroalkyl substances (PFASs). Exposure to PFASs during early stages of life may lead to adverse health effects among breastfed infants. To date, perfluorootanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been most frequently measured PFASs in breast milks worldwide. Information on shorter carbon-chain PFASs in breast milk is scarce. In this study, breast milks were sampled from 264 Korean lactating women, and measured for seventeen PFASs, including ten perfluoroalkyl carboxylates (PFCAs), four perfluoroalkyl sulfonates, and three perfluoroalkyl sulfonamides. PFOA and PFOS were detected in 98.5% of the breast milk samples, with median concentrations of 0.072 and 0.050ng/mL, respectively. Perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), and perfluoroheptanoic acid (PFHpA) were detected in higher frequencies, ranging between 67.4% and 81.8%. The concentrations of short carbon-chain PFCAs in breast milk such as PFPeA and PFHxA were the highest ever reported to date, and were comparable to that of PFOS. Concentrations of shorter chain PFCA in breast milk tended to be higher among the women with longer lactation period, while those of PFOA showed the opposite trend, suggesting a possibility that breastfeeding might be an important route of excretion for PFOA among lactating women. Fish consumption and the use of consumer products, e.g., skin care products, cosmetics and non-stick coated cooking utensils, were identified as significant predictors of PFAS concentrations in breast milk. Health risks associated with PFOA and PFOS exposure through breastfeeding were estimated negligible, however, risks of the short carbon-chain PFCAs could not be assessed because of lack of relevant toxicological information. Further efforts for source identification and exposure management measures for shorter chain PFCAs are necessary. Copyright © 2016 Elsevier Inc. All rights reserved.

An in vitro fatty acylation assay reveals a mechanism for Wnt recognition by the acyltransferase Porcupine.

Science.gov (United States)

Asciolla, James J; Miele, Matthew M; Hendrickson, Ronald C; Resh, Marilyn D

2017-08-18

Wnt proteins are a family of secreted signaling proteins that play key roles in regulating cell proliferation in both embryonic and adult tissues. Production of active Wnt depends on attachment of palmitoleate, a monounsaturated fatty acid, to a conserved serine by the acyltransferase Porcupine (PORCN). Studies of PORCN activity relied on cell-based fatty acylation and signaling assays as no direct enzyme assay had yet been developed. Here, we present the first in vitro assay that accurately recapitulates PORCN-mediated fatty acylation of a Wnt substrate. The critical feature is the use of a double disulfide-bonded Wnt peptide that mimics the two-dimensional structure surrounding the Wnt acylation site. PORCN-mediated Wnt acylation was abolished when the Wnt peptide was treated with DTT, and did not occur with a linear (non-disulfide-bonded) peptide, or when the double disulfide-bonded Wnt peptide contained Ala substituted for the Ser acylation site. We exploited this in vitro Wnt acylation assay to provide direct evidence that the small molecule LGK974, which is in clinical trials for managing Wnt-driven tumors, is a bona fide PORCN inhibitor whose IC 50 for inhibition of Wnt fatty acylation in vitro closely matches that for inhibition of Wnt signaling. Side-by-side comparison of PORCN and Hedgehog acyltransferase (HHAT), two enzymes that attach 16-carbon fatty acids to secreted proteins, revealed that neither enzyme will accept the other's fatty acyl-CoA or peptide substrates. These findings illustrate the unique enzyme-substrate selectivity exhibited by members of the membrane-bound O -acyl transferase family. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Binding of acyl CoA by fatty acid binding protein and the effect on fatty acid activation

International Nuclear Information System (INIS)

Burrier, R.E.; Manson, C.R.; Brecher, P.

1987-01-01

The ability of purified rat liver and heart fatty acid binding proteins (FABPs) to bind oleoyl CoA and modulate acyl CoA synthesis by microsomal membranes was investigated. Using binding assays employing either Lipidex 1000 or multilamellar liposomes to sequester unbound ligand, rat liver but not rat heart FABP was shown to bind radiolabeled acyl CoA. Binding studies suggest that liver FABP has a single binding site for acyl CoA which is separate from the two binding sites for fatty acids. Experiments were then performed to determine how binding may influence acyl CoA metabolism by liver microsomes or heart sarcoplasmic reticulum. Using liposomes as fatty acid donors, liver FABP stimulated acyl CoA production whereas heart FABP did not stimulate production over control values. 14 C-Fatty acid-FABP complexes were prepared, incubated with membranes and acyl CoA synthetase activity was determined. Up to 70% of the fatty acid could be converted to acyl CoA in the presence of liver FABP but in the presence of heart FABP, only 45% of the fatty acid was converted. The amount of product formed was not changed by additional membrane, enzyme cofactor, or incubation time. Liver but not heart FABP bound the acyl CoA formed and removed it from the membranes. These studies suggest that liver FABP can increase the amount of acyl CoA by binding this ligand thereby removing it from the membrane and possibly aiding transport within the cell

Binding of acyl CoA by fatty acid binding protein and the effect on fatty acid activation

Energy Technology Data Exchange (ETDEWEB)

Burrier, R.E.; Manson, C.R.; Brecher, P.

1987-05-01

The ability of purified rat liver and heart fatty acid binding proteins (FABPs) to bind oleoyl CoA and modulate acyl CoA synthesis by microsomal membranes was investigated. Using binding assays employing either Lipidex 1000 or multilamellar liposomes to sequester unbound ligand, rat liver but not rat heart FABP was shown to bind radiolabeled acyl CoA. Binding studies suggest that liver FABP has a single binding site for acyl CoA which is separate from the two binding sites for fatty acids. Experiments were then performed to determine how binding may influence acyl CoA metabolism by liver microsomes or heart sarcoplasmic reticulum. Using liposomes as fatty acid donors, liver FABP stimulated acyl CoA production whereas heart FABP did not stimulate production over control values. /sup 14/C-Fatty acid-FABP complexes were prepared, incubated with membranes and acyl CoA synthetase activity was determined. Up to 70% of the fatty acid could be converted to acyl CoA in the presence of liver FABP but in the presence of heart FABP, only 45% of the fatty acid was converted. The amount of product formed was not changed by additional membrane, enzyme cofactor, or incubation time. Liver but not heart FABP bound the acyl CoA formed and removed it from the membranes. These studies suggest that liver FABP can increase the amount of acyl CoA by binding this ligand thereby removing it from the membrane and possibly aiding transport within the cell.

Attempts to Synthesize 3-acyl-4-hydroxycoumarins from Meldrum’s acid -- and Related Chemistry

OpenAIRE

Ye, Fengbin; Tropp, Kristin; Yu, Yiting

2007-01-01

We start our synthetic work with the acylation of Meldrum’s acid to get three different 5-acyl Meldrum’s acids. These compounds are attacked by various nucleophiles containing different hetero atoms to obtain β-ketoesters, β-ketoamides and the corresponding β-keto-phosphorus compounds respectively. New β-ketoamides could be synthesized and characterized. The reaction of acylated Meldrum’s acid and diphenylphosphine did not lead to the expected β-keto-phosphide compound, but the resulting prod...

The utilization of the acyl-CoA and the involvement PDAT and DGAT in the biosynthesis of erucic acid-rich triacylglycerols in Crambe seed oil.

Science.gov (United States)

Furmanek, Tomasz; Demski, Kamil; Banaś, Walentyna; Haslam, Richard; Napier, Jonathan; Stymne, Sten; Banaś, Antoni

2014-04-01

The triacylglycerol of Crambe abyssinica seeds consist of 95% very long chain (>18 carbon) fatty acids (86% erucic acid; 22:1∆13) in the sn-1 and sn-3 positions. This would suggest that C. abyssinica triacylglycerols are not formed by the action of the phospholipid:diacylglycerol acyltransferase (PDAT), but are rather the results of acyl-CoA:diacylglycerol acyltransferase (DGAT) activity. However, measurements of PDAT and DGAT activities in microsomal membranes showed that C. abyssinica has significant PDAT activity, corresponding to about 10% of the DGAT activity during periods of rapid seed oil accumulation. The specific activity of DGAT for erucoyl-CoA had doubled at 19 days after flowering compared to earlier developmental stages, and was, at that stage, the preferred acyl donor, whereas the activities for 16:0-CoA and 18:1-CoA remained constant. This indicates that an expression of an isoform of DGAT with high specificity for erucoyl-CoA is induced at the onset of rapid erucic acid and oil accumulation in the C. abyssinica seeds. Analysis of the composition of the acyl-CoA pool during different stages of seed development showed that the percentage of erucoyl groups in acyl-CoA was much higher than in complex lipids at all stages of seed development except in the desiccation phase. These results are in accordance with published results showing that the rate limiting step in erucic acid accumulation in C. abyssinica oil is the utilization of erucoyl-CoA by the acyltransferases in the glycerol-3-phosphate pathway.

Role of colonic short-chain fatty acid transport in diarrhea.

Science.gov (United States)

Binder, Henry J

2010-01-01

Short-chain fatty acids (SCFA) are the major anion in stool and are synthesized from nonabsorbed carbohydrate by the colonic microbiota. Nonabsorbed carbohydrate are not absorbed in the colon and induce an osmotically mediated diarrhea; in contrast, SCFA are absorbed by colonic epithelial cells and stimulate Na-dependent fluid absorption via a cyclic AMP-independent process involving apical membrane Na-H, SCFA-HCO(3), and Cl-SCFA exchanges. SCFA production represents an adaptive process to conserve calories, fluid, and electrolytes. Inhibition of SCFA synthesis by antibiotics and administration of PEG, a substance that is not metabolized by colonic microbiota, both result in diarrhea. In contrast, increased production of SCFA as a result of providing starch that is relatively resistant to amylase digestion [so-called resistant starch (RS)] to oral rehydration solution (RS-ORS) improves the efficacy of ORS and represents an important approach to improve the effectiveness of ORS in the treatment of acute diarrhea in children under five years of age.

Systematic Analysis of Gene Expression Alterations and Clinical Outcomes for Long-Chain Acyl-Coenzyme A Synthetase Family in Cancer.

Directory of Open Access Journals (Sweden)

Wei-Ching Chen

Full Text Available Dysregulated lipid metabolism contributes to cancer progression. Our previous study indicates that long-chain fatty acyl-Co A synthetase (ACSL 3 is essential for lipid upregulation induced by endoplasmic reticulum stress. In this report, we aimed to identify the role of ACSL family in cancer with systematic analysis and in vitro experiment. We explored the ACSL expression using Oncomine database to determine the gene alteration during carcinogenesis and identified the association between ACSL expression and the survival of cancer patient using PrognoScan database. ACSL1 may play a potential oncogenic role in colorectal and breast cancer and play a potential tumor suppressor role in lung cancer. Co-expression analysis revealed that ACSL1 was coexpressed with MYBPH, PTPRE, PFKFB3, SOCS3 in colon cancer and with LRRFIP1, TSC22D1 in lung cancer. In accordance with PrognoScan analysis, downregulation of ACSL1 in colon and breast cancer cell line inhibited proliferation, migration, and anchorage-independent growth. In contrast, increase of oncogenic property was observed in lung cancer cell line by attenuating ACSL1. High ACSL3 expression predicted a better prognosis in ovarian cancer; in contrast, high ACSL3 predicted a worse prognosis in melanoma. ACSL3 was coexpressed with SNUPN, TRIP13, and SEMA5A in melanoma. High expression of ACSL4 predicted a worse prognosis in colorectal cancer, but predicted better prognosis in breast, brain and lung cancer. ACSL4 was coexpressed with SERPIN2, HNRNPCL1, ITIH2, PROCR, LRRFIP1. High expression of ACSL5 predicted good prognosis in breast, ovarian, and lung cancers. ACSL5 was coexpressed with TMEM140, TAPBPL, BIRC3, PTPRE, and SERPINB1. Low ACSL6 predicted a worse prognosis in acute myeloid leukemia. ACSL6 was coexpressed with SOX6 and DARC. Altogether, different members of ACSLs are implicated in diverse types of cancer development. ACSL-coexpressed molecules may be used to further investigate the role of ACSL

Accumulation of N-acyl-ethanolamine phospholipids in rat brains during post-decapitative ischemia

DEFF Research Database (Denmark)

Moesgaard, B.; Hansen, Harald S.; Jaroszewski, J.W.

1999-01-01

-phospho(N-acyl)-ethanolamine (NAPE(PLAS)), respectively, by spiking with authentic materials. Additionally, the identification was verified by thin-layer chromatography, which also showed the accumulation of N-acyl-ethanolamine phospholipids. The use of K-EDTA instead of the commonly used Cs...

Small angle neutron scattering study on short and long chain phosphatidylcholine mixture in trehalose solution

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Hiroshi [Department of Physics, Gunma University, Maebashi, Gunma (Japan)

2001-03-01

Trehalose protects cells and proteins against various stresses due to low temperatures or dryness. In order to clarify the molecular mechanism of cryoprotective function of trehalose, we have studied the interaction between trehalose and phosphatidylcholine (PC) which is a main lipid component of cell membranes. In this study, the structural change of a binary PC mixture by the presence of trehalose was investigated by means of small angle neutron scattering. The PC binary mixture studied contains dihexanoyl-PC (diC{sub 6}PC) and dihexadecy-PC (DHPC). The former has short hydrocarbon chains and the latter has long hydrocarbon chains. The scattering profiles from the DHPC/diC{sub 6}PC mixture were changed, depending on trehalose concentrations. This change can be interpreted as suggesting that the presence of trehalose reduces the interfacial area between water and PCs. (author)

Novel short chain chloroquine analogues retain activity against chloroquine resistant K1 Plasmodium falciparum.

Science.gov (United States)

Stocks, Paul A; Raynes, Kaylene J; Bray, Patrick G; Park, B Kevin; O'Neill, Paul M; Ward, Stephen A

2002-11-07

A series of short chain chloroquine (CQ) derivatives have been synthesized in one step from readily available starting materials. The diethylamine function of CQ is replaced by shorter alkylamine groups (4-9) containing secondary or tertiary terminal nitrogens. Some of these derivatives are significantly more potent than CQ against a CQ resistant strain of Plasmodium falciparum in vitro. We conclude that the ability to accumulate at higher concentrations within the food vacuole of the parasite is an important parameter that dictates their potency against CQ sensitive and the chloroquine resistant K1 P. falciparum.

Plasma levels of acylated and total ghrelin in pediatric patients with chronic kidney disease.

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Naufel, Maria Fernanda Soares; Bordon, Milena; de Aquino, Talita Marques; Ribeiro, Eliane Beraldi; de Abreu Carvalhaes, João Tomás

2010-12-01

This cross-sectional study set out to compare total and acyl ghrelin levels in children with mild chronic kidney disease (CKD) undergoing conservative treatment (n = 19) with children with end-stage renal disease (ESRD) undergoing hemodialysis (n = 24), and with healthy controls (n = 20). The relationship between ghrelin levels and parameters of renal function, nutritional status, and selective hormones were investigated. ESRD patients had higher total ghrelin levels than those with mild CKD or control individuals. However, acyl ghrelin did not differ between groups, indicating that the excess circulating ghrelin was desacylated. Since desacyl ghrelin has been shown to inhibit appetite, increased levels might contribute to protein-energy wasting in pediatric renal patients. When all 43 renal patients were combined, multiple regression analysis found age and glomerular filtration rate (GFR) to be significant negative predictors of total ghrelin. Acyl ghrelin was influenced negatively by age and positively by energy intake. Acyl to total ghrelin ratio related positively to GFR and energy intake. The results indicate that total but not acyl ghrelin is influenced by low GFR in children with CKD and suggests that ghrelin activation may be impaired in these patients. Since energy intake is a positive predictor of acyl ghrelin, the physiological control of ghrelin secretion appears to be altered in pediatric renal patients.

Enantioselective N-Heterocyclic Carbene Catalysis via the Dienyl Acyl Azolium.

Science.gov (United States)

Gillard, Rachel M; Fernando, Jared E M; Lupton, David W

2018-04-16

Herein we report the enantioselective N-heterocyclic carbene catalyzed (4+2) annulation of the dienyl acyl azolium with enolates. The reaction exploits readily accessible acyl fluorides and TMS enol ethers to give a range of highly enantio- and diastereo-enriched cyclohexenes (most >97:3 er and >20:1 dr). The reaction was found to require high nucleophilicity NHC catalysts with mechanistic studies supporting a stepwise 1,6-addition/β-lactonization. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Atmospheric chemistry of short-chain haloolefins: photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs).

Science.gov (United States)

Wallington, T J; Sulbaek Andersen, M P; Nielsen, O J

2015-06-01

Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antihypertensive neutral lipid

Science.gov (United States)

Snyder, F.L.; Blank, M.L.

1984-10-26

The invention relates to the discovery of a class of neutral acetylated either-linked glycerolipids having the capacity to lower blood presure in warm-blooded animals. This physiological effect is structure sensitive requiring a long chain alkyl group at the sn-1 position and a short carbon chain acyl group (acetyl or propionyl) at the sn-2 position, and a hydroxyl group at the sn-3 position.

Microbial synthesis of a branched-chain ester platform from organic waste carboxylates

Directory of Open Access Journals (Sweden)

Donovan S. Layton

2016-12-01

Full Text Available Processing of lignocellulosic biomass or organic wastes produces a plethora of chemicals such as short, linear carboxylic acids, known as carboxylates, derived from anaerobic digestion. While these carboxylates have low values and are inhibitory to microbes during fermentation, they can be biologically upgraded to high-value products. In this study, we expanded our general framework for biological upgrading of carboxylates to branched-chain esters by using three highly active alcohol acyltransferases (AATs for alcohol and acyl CoA condensation and modulating the alcohol moiety from ethanol to isobutanol in the modular chassis cell. With this framework, we demonstrated the production of an ester library comprised of 16 out of all 18 potential esters, including acetate, propionate, butanoate, pentanoate, and hexanoate esters, from the 5 linear, saturated C2-C6 carboxylic acids. Among these esters, 5 new branched-chain esters, including isobutyl acetate, isobutyl propionate, isobutyl butyrate, isobutyl pentanoate, and isobutyl hexanoate were synthesized in vivo. During 24 h in situ fermentation and extraction, one of the engineered strains, EcDL208 harnessing the SAAT of Fragaria ananassa produced ~63 mg/L of a mixture of butyl and isobutyl butyrates from glucose and butyrate co-fermentation and ~127 mg/L of a mixture of isobutyl and pentyl pentanoates from glucose and pentanoate co-fermentation, with high specificity. These butyrate and pentanoate esters are potential drop-in liquid fuels. This study provides better understanding of functional roles of AATs for microbial biosynthesis of branched-chain esters and expands the potential use of these esters as drop-in biofuels beyond their conventional flavor, fragrance, and solvent applications. Keywords: Carboxylate platform, Ester platform, Branched-chain ester, Modular cell, Biological upgrading, Organic waste, Lignocellulosic biomass, Isobutyl esters

Expression of the short chain fatty acid receptor GPR41/FFAR3 in autonomic and somatic sensory ganglia

DEFF Research Database (Denmark)

Nøhr, Mark Klitgaard; Egerod, K L; Christiansen, S H

2015-01-01

G-protein-coupled receptor 41 (GPR41) also called free fatty acid receptor 3 (FFAR3) is a Gαi-coupled receptor activated by short-chain fatty acids (SCFAs) mainly produced from dietary complex carbohydrate fibers in the large intestine as products of fermentation by microbiota. FFAR3 is expressed...

Influence of trehalose 6,6'-diester (TDX) chain length on the physicochemical and immunopotentiating properties of DDA/TDX liposomes

DEFF Research Database (Denmark)

Kallerup, Rie Selchau; Madsen, Cecilie Maria; Schiøth, Mikkel Lohmann

2015-01-01

Linking physicochemical characterization to functional properties is crucial for defining critical quality attributes during development of subunit vaccines toward optimal safety and efficacy profiles. We investigated how the trehalose 6,6'-diester (TDX) chain length influenced the physicochemical...... and immunopotentiating properties of the clinically tested liposomal adjuvant composed of dimethyldioctadecylammonium (DDA) bromide and analogues of trehalose-6,6'-dibehenate (TDB). TDB analogues with symmetrically shortened acyl chains [denoted X: arachidate (A), stearate (S), palmitate (P), myristate (Myr) and laurate...

Characterization of acyl-coenzyme A:diacylglycerol acyltransferase (DGAT) enzyme of human small intestine.

Science.gov (United States)

Hiramine, Yasushi; Tanabe, Toshizumi

2011-06-01

Acyl-coenzyme A:diacylglycerol acyltransferase (DGAT) enzyme plays a significant role in dietary triacylglycerol (TAG) absorption in the small intestine. However, the characteristics of human intestinal DGAT enzyme have not been examined in detail. The aim of our study was to characterize the human intestinal DGAT enzyme by examining acyl-CoA specificity, temperature dependency, and selectivity for 1,2-diacylglycerol (DAG) or 1,3-DAG. We detected DGAT activity of human intestinal microsome and found that the acyl-CoA specificity and temperature dependency of intestinal DGAT coincided with those of recombinant human DGAT1. To elucidate the selectivity of human intestinal DGAT to 1,2-DAG or 1,3-DAG, we conducted acyl-coenzyme A:monoacylglycerol acyltransferase assays using 1- or 2-monoacylglycerol (MAG) as substrates. When 2-MAG was used as acyl acceptor, both 1,2-DAG and TAG were generated; however, when 1-MAG was used, 1,3-DAG was predominantly observed and little TAG was detected. These findings suggest that human small intestinal DGAT, which is mainly encoded by DGAT1, utilizes 1,2-DAG as the substrate to form TAG. This study will contribute to understand the lipid absorption profile in the small intestine.

Diversion procto-colitis: response to treatment with short-chain fatty acids.

Science.gov (United States)

Kiely, E M; Ajayi, N A; Wheeler, R A; Malone, M

2001-10-01

Diversion procto-colitis (DPC) results from a deficiency of luminal short-chain fatty acids (SCFAs). Endoscopic and histopathologic features of the disorder are almost universally present in defunctioned bowel, but symptomatic DPC is less common. Five children with symptomatic DPC underwent endoscopy and rectosigmoid biopsies. An endoscopic index (EI) was used to quantify disease severity. An SCFA mixture was administered into the defunctioned bowel. A good clinical response and improvement in the endoscopic index occurred in all children. Undiversion or rectal excision was carried out in 4 and was curative in each case. One child is awaiting a redo pull through. DPC should be considered in children with a defunctioned colon presenting with evidence of colitis. Histopathology provides supportive evidence and SCFAs may provide effective relief of symptoms. Stoma reversal or rectal excision is curative. Copyright 2001 by W.B. Saunders Company.

Compared effects of missense mutations in Very-Long-Chain Acyl-CoA Dehydrogenase deficiency: Combined analysis by structural, functional and pharmacological approaches.

Science.gov (United States)

Gobin-Limballe, Stéphanie; McAndrew, Ryan P; Djouadi, Fatima; Kim, Jung-Ja; Bastin, Jean

2010-05-01

Very-Long-Chain Acyl-CoA Dehydrogenase deficiency (VLCADD) is an autosomal recessive disorder considered as one of the more common ss-oxidation defects, possibly associated with neonatal cardiomyopathy, infantile hepatic coma, or adult-onset myopathy. Numerous gene missense mutations have been described in these VLCADD phenotypes, but only few of them have been structurally and functionally analyzed, and the molecular basis of disease variability is still poorly understood. To address this question, we first analyzed fourteen disease-causing amino acid changes using the recently described crystal structure of VLCAD. The predicted effects varied from the replacement of amino acid residues lining the substrate binding cavity, involved in holoenzyme-FAD interactions or in enzyme dimerisation, predicted to have severe functional consequences, up to amino acid substitutions outside key enzyme domains or lying on near enzyme surface, with predicted milder consequences. These data were combined with functional analysis of residual fatty acid oxidation (FAO) and VLCAD protein levels in patient cells harboring these mutations, before and after pharmacological stimulation by bezafibrate. Mutations identified as detrimental to the protein structure in the 3-D model were generally associated to profound FAO and VLCAD protein deficiencies in the patient cells, however, some mutations affecting FAD binding or monomer-monomer interactions allowed a partial response to bezafibrate. On the other hand, bezafibrate restored near-normal FAO rates in some mutations predicted to have milder consequences on enzyme structure. Overall, combination of structural, biochemical, and pharmacological analysis allowed assessment of the relative severity of individual mutations, with possible applications for disease management and therapeutic approach. Copyright 2010 Elsevier B.V. All rights reserved.

Incipient microphase separation in short chain perfluoropolyether-block-poly(ethylene oxide) copolymers.

Science.gov (United States)

Chintapalli, Mahati; Timachova, Ksenia; Olson, Kevin R; Banaszak, Michał; Thelen, Jacob L; Mecham, Sue J; DeSimone, Joseph M; Balsara, Nitash P

2017-06-07

Incipient microphase separation is observed by wide angle X-ray scattering (WAXS) in short chain multiblock copolymers consisting of perfluoropolyether (PFPE) and poly(ethylene oxide) (PEO) segments. Two PFPE-PEO block copolymers were studied; one with dihydroxyl end groups and one with dimethyl carbonate end groups. Despite having a low degree of polymerization (N ∼ 10), these materials exhibited significant scattering intensity, due to disordered concentration fluctuations between their PFPE-rich and PEO-rich domains. The disordered scattering intensity was fit to a model based on a multicomponent random phase approximation to determine the value of the interaction parameter, χ, and the radius of gyration, R g . Over the temperature range 30-90 °C, the values of χ were determined to be very large (∼2-2.5), indicating a high degree of immiscibility between the PFPE and PEO blocks. In PFPE-PEO, due to the large electron density contrast between the fluorinated and non-fluorinated block and the high value of χ, disordered scattering was detected at intermediate scattering angles, (q ∼ 2 nm -1 ) for relatively small polymer chains. Our ability to detect concentration fluctuations was enabled by both a relatively large value of χ and significant scattering contrast.

Suppression of acyl migration in enzymatic production of structured lipids through temperature programming

DEFF Research Database (Denmark)

Yang, Tiankui; Fruekilde, Maj-Britt; Xu, Xuebing

2005-01-01

Acyl migration in the glycerol backbone often leads to the increase of by-products in the enzymatic production of specific structured lipids. Acyl migration is a thermodynamic process and is very difficult to stop fully in actual reactions. The objective of this study was to investigate...

Reaction of tantalum-alkyne complexes with isocyanates or acyl cyanides

International Nuclear Information System (INIS)

Kataoka, Yasutaka; Oguchi, Yoshiyuki; Yoshizumi, Kazuyuki; Miwatashi, Seiji; Takai, Kazuhiko; Utimoto, Kiitiro

1992-01-01

Treatment of alkynes with low-valent tantalum derived from TiCl 5 and zinc produces tantalum-alkyne complexes (not isolated), which react in situ with phenyl isocyanate (or butyl isocyanate) to give (E)-α, β-unsaturated amides stereoselectively. The tantalum-alkyne complexes also react with acyl cyanides in the presence of BF 3 ·OEt 2 to give α-cyanohydrins. In both reactions, filtration of the reaction mixture containing the tantalum-alkyne complexes before addition of isocyanates (or acyl cyanides) is indispensable to obtain good yields. (author)

Disruption of the acyl-coa binding protein gene delays hepatic adaptation to metabolic changes at weaning

DEFF Research Database (Denmark)

Neess, Ditte; Bloksgaard, Maria; Sørensen, Signe Bek

2011-01-01

The acyl-CoA binding protein/diazepam binding inhibitor (ACBP/DBI) is an intracellular protein that binds C14-C22 acyl-CoA esters and is thought to act as an acyl-CoA transporter. In vitro analyses have indicated that ACBP can transport acyl-CoA esters between different enzymatic systems; however....... The delayed induction of SREBP target genes around weaning is caused by a compromised processing and decreased expression of SREBP precursors leading to reduced binding of SREBP to target sites in chromatin. In conclusion, lack of ACBP interferes with the normal metabolic adaptation to weaning and leads...

Gut microbiota alterations and dietary modulation in childhood malnutrition - The role of short chain fatty acids.

Science.gov (United States)

Pekmez, Ceyda Tugba; Dragsted, Lars Ove; Brahe, Lena Kirchner

2018-02-17

The gut microbiome affects the health status of the host through different mechanisms and is associated with a wide variety of diseases. Both childhood undernutrition and obesity are linked to alterations in composition and functionality of the gut microbiome. One of the possible mechanisms underlying the interplay between microbiota and host metabolism is through appetite-regulating hormones (including leptin, ghrelin, glucagon-like peptide-1). Short chain fatty acids, the end product of bacterial fermentation of non-digestible carbohydrates, might be able to alter energy harvest and metabolism through enteroendocrine cell signaling, adipogenesis and insulin-like growth factor-1 production. Elucidating these mechanisms may lead to development of new modulation practices of the gut microbiota as a potential prevention and treatment strategy for childhood malnutrition. The present overview will briefly outline the gut microbiota development in the early life, gut microbiota alterations in childhood undernutrition and obesity, and whether this relationship is causal. Further we will discuss possible underlying mechanisms in relation to the gut-brain axis and short chain fatty acids, and the potential of probiotics, prebiotics and synbiotics for modulating the gut microbiota during childhood as a prevention and treatment strategy against undernutrition and obesity. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men.

Science.gov (United States)

Broom, David R; Miyashita, Masashi; Wasse, Lucy K; Pulsford, Richard; King, James A; Thackray, Alice E; Stensel, David J

2017-03-01

Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-h conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55-min running at 52% peak oxygen uptake (V.O 2peak )) and VIG (36-min running at 75% V.O 2peak ). In experiment two, nine healthy males completed three, 9-h conditions (control, 45-min running (EX45) and 90-min running (EX90)). Exercise was performed at 70% V.O 2peak In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES = 0.44, P = 0.01) and VIG (ES = 0.98, P Hunger ratings were similar across the conditions (P = 0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES = 0.77, P Hunger ratings were lower than control in EX45 (ES = 0.20, P = 0.01) and EX90 (ES = 0.27, P = 0.001); EX45 and EX90 were similar (ES = 0.07, P = 0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5 h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise. © 2017 Society for Endocrinology.

The Role of Short-Chain Conjugated Poly-(R-3-Hydroxybutyrate (cPHB in Protein Folding

Directory of Open Access Journals (Sweden)

Rosetta N. Reusch

2013-05-01

Full Text Available Poly-(R-3-hydroxybutyrate (PHB, a linear polymer of R-3-hydroxybutyrate (R-3HB, is a fundamental constituent of biological cells. Certain prokaryotes accumulate PHB of very high molecular weight (10,000 to >1,000,000 residues, which is segregated within granular deposits in the cytoplasm; however, all prokaryotes and all eukaryotes synthesize PHB of medium-chain length (~100–200 residues which resides within lipid bilayers or lipid vesicles, and PHB of short-chain length (<12 residues which is conjugated to proteins (cPHB, primarily proteins in membranes and organelles. The physical properties of cPHB indicate it plays important roles in the targeting and folding of cPHB-proteins. Here we review the occurrence, physical properties and molecular characteristics of cPHB, and discuss its influence on the folding and structure of outer membrane protein A (OmpA of Escherichia coli.

Distribution of short block copolymer chains in Binary Blends of Block Copolymers Having Hydrogen Bonding

Science.gov (United States)

Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon

2014-03-01

A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.

Interaction of gamma-glutamyltranspeptidase with clofibryl-S-acyl-glutathione in vitro and in vivo in rat.

Science.gov (United States)

Grillo, M P; Benet, L Z

2001-08-01

Clofibric acid (CA) is metabolized to chemically reactive acylating products that can transacylate glutathione to form clofibryl-S-acyl-glutathione (CA-SG) in vitro and in vivo. We investigated the first step in the degradation of CA-SG to the mercapturic acid conjugate, clofibryl-S-acyl-N-acetylcysteine (CA-SNAC), which is catalyzed by gamma-glutamyltranspeptidase (gamma-GT). After gamma-GT mediated cleavage of glutamate from CA-SG, the product clofibryl-S-acyl-cysteinylglycine (CA-S-CG) should undergo an intramolecular rearrangement reaction [Tate, S. S. (1975) FEBS Lett. 54, 319-322] to form clofibryl-N-acyl-cysteinylglycine (CA-N-CG). We performed in vitro studies incubating CA-SG with gamma-GT to determine the products formed, and in vivo studies examining the products excreted in urine after dosing rats with CA-SG or CA. Thus, CA-SG (0.1 mM) was incubated with gamma-GT (0.1 unit/mL) in buffer (pH 7.4, 25 degrees C) and analyzed for products formed by reversed-phase HPLC and electrospray mass spectrometry (ESI/MS). Results showed that CA-SG is degraded completely after 6 h of incubation leading to the formation of two products, CA-N-CG and its disulfide, with no detection of CA-S-CG thioester. After 36 h of incubation, only the disulfide remained in the incubation. Treatment of the disulfide with dithiothreitol led to the reappearance of CA-N-CG. ESI/LC/MS analysis of urine (16 h) extracts of CA-SG-dosed rats (200 mg/kg, iv) showed that CA-SG is degraded to CA-N-CG, CA-N-acyl-cysteine (CA-N-C) and their respective S-methylated products. The mercapturic acid conjugate (CA-SNAC) was found as a minor product. Analysis of urine extracts from CA-dosed rats (200 mg/kg, ip) resulted in the detection of clofibryl-N-acyl-cysteine (CA-N-C), but no evidence for the formation of CA-SNAC was obtained. These in vitro and in vivo experiments indicate that gamma-GT mediated degradation of clofibryl-S-acyl-glutathione leads primarily to the formation and excretion of clofibryl-N-acyl

Targeted Lipidomics in Drosophila melanogaster Identifies Novel 2-Monoacylglycerols and N-acyl Amides

Science.gov (United States)

Takacs, Sara M.; Stuart, Jordyn M.; Basnet, Arjun; Raboune, Siham; Widlanski, Theodore S.; Doherty, Patrick; Bradshaw, Heather B.

2013-01-01

Lipid metabolism is critical to coordinate organ development and physiology in response to tissue-autonomous signals and environmental cues. Changes to the availability and signaling of lipid mediators can limit competitiveness, adaptation to environmental stressors, and augment pathological processes. Two classes of lipids, the N-acyl amides and the 2-acyl glycerols, have emerged as important signaling molecules in a wide range of species with important signaling properties, though most of what is known about their cellular functions is from mammalian models. Therefore, expanding available knowledge on the repertoire of these lipids in invertebrates will provide additional avenues of research aimed at elucidating biosynthetic, metabolic, and signaling properties of these molecules. Drosophila melanogaster is a commonly used organism to study intercellular communication, including the functions of bioactive lipids. However, limited information is available on the molecular identity of lipids with putative biological activities in Drosophila. Here, we used a targeted lipidomics approach to identify putative signaling lipids in third instar Drosophila larvae, possessing particularly large lipid mass in their fat body. We identified 2-linoleoyl glycerol, 2-oleoyl glycerol, and 45 N-acyl amides in larval tissues, and validated our findings by the comparative analysis of Oregon-RS, Canton-S and w1118 strains. Data here suggest that Drosophila represent another model system to use for the study of 2-acyl glycerol and N-acyl amide signaling. PMID:23874457

Establishing very long-chain fatty alcohol and wax ester biosynthesis in Saccharomyces cerevisiae.

Science.gov (United States)

Wenning, Leonie; Yu, Tao; David, Florian; Nielsen, Jens; Siewers, Verena

2017-05-01

Wax esters (WEs) are neutral lipids and can be used for a broad range of commercial applications, including personal care products, lubricants, or coatings. They are synthesized by enzymatic reactions catalyzed by a fatty acyl reductase (FAR) and a wax ester synthase (WS). At present, commercially used WEs are mainly isolated from Simmondsia chinensis (jojoba), but the high extraction costs and limited harvest areas constrain their use. The use of FARs in combination with different WSs to achieve a synthesis of jojoba-like WEs in bacteria and yeast has been reported previously, but the products were restricted to C28-C36 WEs. These rather short WEs make up only a very small percentage of the total WEs in natural jojoba oil. The synthesis of longer chain WEs (up to C44) in Saccharomyces cerevisiae has so far only been achieved after substrate feeding. Here we identified new routes for producing very long-chain fatty alcohols (VLCFOHs) up to a chain length of C22 by heterologous expression of a FAR derived from Apis mellifera (AmFAR1) or Marinobacter aquaeolei VT8 (Maqu_2220) in S. cerevisiae and achieved maximum yields of 3.22 ± 0.36 mg/g cell dry weight (CDW) and 7.84 ± 3.09 mg/g CDW, respectively, after 48 h. Moreover, we enabled the synthesis of jojoba-like WEs up to a chain length of C42, catalyzed by a combination of Maqu_2220 together with the WS from S. chinensis (SciWS) and the S. cerevisiae elongase Elo2p, with a maximum yield of 12.24 ± 3.35 mg/g CDW after 48 h. Biotechnol. Bioeng. 2017;114: 1025-1035. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Natural separation of the acyl-CoA ligase reaction results in a non-adenylating enzyme.

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Wang, Nan; Rudolf, Jeffrey D; Dong, Liao-Bin; Osipiuk, Jerzy; Hatzos-Skintges, Catherine; Endres, Michael; Chang, Chin-Yuan; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N; Shen, Ben

2018-06-04

Acyl-coenzyme A (CoA) ligases catalyze the activation of carboxylic acids via a two-step reaction of adenylation followed by thioesterification. Here, we report the discovery of a non-adenylating acyl-CoA ligase PtmA2 and the functional separation of an acyl-CoA ligase reaction. Both PtmA1 and PtmA2, two acyl-CoA ligases from the biosynthetic pathway of platensimycin and platencin, are necessary for the two steps of CoA activation. Gene inactivation of ptmA1 and ptmA2 resulted in the accumulation of free acid and adenylate intermediates, respectively. Enzymatic and structural characterization of PtmA2 confirmed its ability to only catalyze thioesterification. Structural characterization of PtmA2 revealed it binds both free acid and adenylate substrates and undergoes the established mechanism of domain alternation. Finally, site-directed mutagenesis restored both the adenylation and complete CoA activation reactions. This study challenges the currently accepted paradigm of adenylating enzymes and inspires future investigations on functionally separated acyl-CoA ligases and their ramifications in biology.

Probing fatty acid metabolism in bacteria, cyanobacteria, green microalgae and diatoms with natural and unnatural fatty acids.

Science.gov (United States)

Beld, Joris; Abbriano, Raffaela; Finzel, Kara; Hildebrand, Mark; Burkart, Michael D

2016-04-01

In both eukaryotes and prokaryotes, fatty acid synthases are responsible for the biosynthesis of fatty acids in an iterative process, extending the fatty acid by two carbon units every cycle. Thus, odd numbered fatty acids are rarely found in nature. We tested whether representatives of diverse microbial phyla have the ability to incorporate odd-chain fatty acids as substrates for their fatty acid synthases and their downstream enzymes. We fed various odd and short chain fatty acids to the bacterium Escherichia coli, cyanobacterium Synechocystis sp. PCC 6803, green microalga Chlamydomonas reinhardtii and diatom Thalassiosira pseudonana. Major differences were observed, specifically in the ability among species to incorporate and elongate short chain fatty acids. We demonstrate that E. coli, C. reinhardtii, and T. pseudonana can produce longer fatty acid products from short chain precursors (C3 and C5), while Synechocystis sp. PCC 6803 lacks this ability. However, Synechocystis can incorporate and elongate longer chain fatty acids due to acyl-acyl carrier protein synthetase (AasS) activity, and knockout of this protein eliminates the ability to incorporate these fatty acids. In addition, expression of a characterized AasS from Vibrio harveyii confers a similar capability to E. coli. The ability to desaturate exogenously added fatty acids was only observed in Synechocystis and C. reinhardtii. We further probed fatty acid metabolism of these organisms by feeding desaturase inhibitors to test the specificity of long-chain fatty acid desaturases. In particular, supplementation with thia fatty acids can alter fatty acid profiles based on the location of the sulfur in the chain. We show that coupling sensitive gas chromatography mass spectrometry to supplementation of unnatural fatty acids can reveal major differences between fatty acid metabolism in various organisms. Often unnatural fatty acids have antibacterial or even therapeutic properties. Feeding of short

Acylated ghrelin concentrations are markedly decreased during pregnancy in mothers with and without gestational diabetes: relationship with cholinesterase.

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Tham, Elaine; Liu, Jianhua; Innis, Sheila; Thompson, David; Gaylinn, Bruce D; Bogarin, Roberto; Haim, Alon; Thorner, Michael O; Chanoine, Jean-Pierre

2009-05-01

Acylated (octanoylated) ghrelin stimulates food intake and growth hormone secretion and is deacylated into desacyl ghrelin by butyrylcholinesterase. Acylated and desacyl ghrelin both promote adipogenesis. Ghrelin concentrations decrease with hyperglycemia and hyperinsulinism. We hypothesized that 1) acylated ghrelin increases during pregnancy, contributing positively to energy balance, but is lower in women with gestational diabetes and 2) butyrylcholinesterase activity is inversely correlated with acylated ghrelin concentrations. In a first group of subjects, using two-site sandwich ghrelin assays that specifically detect full-length forms, we investigated women with and without gestational diabetes (n = 14/group) during pregnancy and after delivery. We examined whether changes in ghrelin during a test meal were correlated with changes in pituitary growth hormone [assessed through calculation of the area under the curve (AUC) during the test meal]. In postpartum subjects, the percent of total ghrelin that is acylated was four to five times higher than previously observed using single antibody assays. During pregnancy, acylated ghrelin concentrations (mean +/- SE) were lower compared with the postpartum period throughout the meal (AUC 1.2 +/- 0.2 vs. 10.2 +/- 1.9 ng.ml(-1).90 min(-1), P < 0.001). In the postpartum, acylated ghrelin and growth hormone were positively correlated (r = 0.50, P = 0.007). Desacyl (but not acylated) ghrelin was increased in subjects with gestational diabetes during and after pregnancy (AUC 15.4 +/- 1.9 vs. 8.6 +/- 1.2 ng.ml(-1).90 min(-1), P = 0.005). In a second group of subjects (n = 13), acylated ghrelin was similarly suppressed during pregnancy. Circulating octanoate concentrations (3.1 +/- 0.5 vs. 4.5 +/- 0.6 microg/ml, P = 0.029) and cholinesterase activity (705 +/- 33 vs. 1,013 +/- 56 U/ml, P < 0.001) were lower during pregnancy compared with the postpartum period. In conclusion, acylated ghrelin markedly decreases during pregnancy

Veronica: Acylated flavone glycosides as chemosystematic markers

DEFF Research Database (Denmark)

Albach, Dirk C.; Grayer, Renée J.; Kite, Geoffrey C.

2005-01-01

HPLC/DAD and LCeMS of an extract of Veronica spicata subgenus Pseudolysimachium, Plantaginaceae) revealed the presence of six 6-hydroxyluteolin glycosides acylated with phenolic acids, three of which are new compounds and which we called spicosides. A flavonoid survey of seven more species...

Saturated very long chain fatty acids are required for the production of infectious human cytomegalovirus progeny.

Directory of Open Access Journals (Sweden)

Emre Koyuncu

Full Text Available Human cytomegalovirus hijacks host cell metabolism, increasing the flux of carbon from glucose to malonyl-CoA, the committed precursor to fatty acid synthesis and elongation. Inhibition of acetyl-CoA carboxylase blocks the production of progeny virus. To probe further the role of fatty acid metabolism during infection, we performed an siRNA screen to identify host cell metabolic enzymes needed for the production of infectious cytomegalovirus progeny. The screen predicted that multiple long chain acyl-CoA synthetases and fatty acid elongases are needed during infection, and the levels of RNAs encoding several of these enzymes were upregulated by the virus. Roles for acyl-CoA synthetases and elongases during infection were confirmed by using small molecule antagonists. Consistent with a role for these enzymes, mass spectrometry-based fatty acid analysis with ¹³C-labeling revealed that malonyl-CoA is consumed by elongases to produce very long chain fatty acids, generating an approximately 8-fold increase in C26-C34 fatty acid tails in infected cells. The virion envelope was yet further enriched in C26-C34 saturated fatty acids, and elongase inhibitors caused the production of virions with lower levels of these fatty acids and markedly reduced infectivity. These results reveal a dependence of cytomegalovirus on very long chain fatty acid metabolism.

Proghrelin peptides: Desacyl ghrelin is a powerful inhibitor of acylated ghrelin, likely to impair physiological effects of acyl ghrelin but not of obestatin A study of pancreatic polypeptide secretion from mouse islets

DEFF Research Database (Denmark)

Kumar, Rajesh; Salehi, Albert; Rehfeld, Jens F

2010-01-01

Proghrelin, produced by the ghrelin (A-like) cells of the gastric mucosa, gives rise to cleavage products, including desacyl ghrelin, acyl ghrelin and obestatin. The products are thought to be secreted concomitantly. In an earlier study we found acyl ghrelin and obestatin, but not desacyl ghrelin...

Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

Directory of Open Access Journals (Sweden)

Marijanović-Rajčić, M.

2008-01-01

Full Text Available The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1. The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašnak spring that is contaminated with volatile chlorinated short-chain hydrocarbons.Drinking water samples were taken from 3 private wells and 1 public water-supply system situated in 3 Zagreb suburbs - Pešćenica, Trnje, and Trešnjevka. The sampling was carried out during 2003 and was undertaken on a seasonal basis. Short-chain chlorinated hydrocarbons - 1,1,1-trichloroethane, carbon tetrachloride, 1,1,2-trichloroethene and 1,1,2,2-tetrachloroethene - were determined by gas chromatography, following "liquid-liquid extraction" in pentane. For that purpose, we applied the gas chromatograph equipped with an electron-capture detector, thermo-programmable operations, and a suitable capillary column. The technique applied was that of split-injection.The groundwater of the City of Zagreb was found to be contaminated with volatile chlorinated hydrocarbons. The concentration level of 1,1,1-trichloroethane, determined in most of the samples, was found to be low (Fig. 2. On the other hand, 1,1,2-trichloroethene was present in all samples in concentrations of about 1 µg l-1- (Fig. 3. Only the drinking water samples taken from private wells in the suburb of Trnje contained somewhat higher mass concentrations of 1,1,1-trichloroethane, with the peak value of 19.03 µg l-1, measured in the winter season. In the samples taken from private wells in Trnje, the mass concentrations of 1,1,2,2-tetrachloroethene rangedfrom 15.30 µg l-1 to 18.65 µg l-1, as measured in autumn

Kinetics of acyl transfer reactions in organic media catalysed by Candida antarctica lipase B.

Science.gov (United States)

Martinelle, M; Hult, K

1995-09-06

The acyl transfer reactions catalysed by Candida antartica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl acceptors. The effect of organic solvents on Vm and Km was investigated. The Vm values in acetonitrile was 40-50% of those in heptane. High Km values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate specificity, defined as (Vm/Km)ethyl octanoate/(Vm/Km)octanoic acid, going from heptane to acetonitrile. Deacylation was the rate determining step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With 1-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using 1-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower Vm/Km value and vinyl octanoate a 4-fold higher Vm/Km value than that for ethyl octanoate. The difference showed to be a Km effect for vinyl octanoate and mainly a Km effect for S-ethyl thiooctanoate. The Vm values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals.

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Biesiekierski, J R; Rosella, O; Rose, R; Liels, K; Barrett, J S; Shepherd, S J; Gibson, P R; Muir, J G

2011-04-01

Wholegrain grains and cereals contain a wide range of potentially protective factors that are relevant to gastrointestinal health. The prebiotics best studied are fructans [fructooligosaccharides (FOS), inulin] and galactooligosaccharides (GOS). These and other short-chain carbohydrates can also be poorly absorbed in the small intestine (named fermentable oligo-, di- and monosaccharides and polyols; FODMAPs) and may have important implications for the health of the gut. In the present study, FODMAPs, including fructose in excess of glucose, FOS (nystose, kestose), GOS (raffinose, stachyose) and sugar polyols (sorbitol, mannitol), were quantified using high-performance liquid chromatography with an evaporative light scattering detector. Total fructan was quantified using an enzymic hydrolysis method. Fifty-five commonly consumed grains, breakfast cereals, breads, pulses and biscuits were analysed. Total fructan were the most common short-chain carbohydrate present in cereal grain products and ranged (g per portion as eaten) from 1.12 g in couscous to 0 g in rice; 0.6 g in dark rye bread to 0.07 g in spelt bread; 0.96 g in wheat-free muesli to 0.11 g in oats; and 0.81 g in muesli fruit bar to 0.05 g in potato chips. Raffinose and stachyose were most common in pulses.   Composition tables including FODMAPs and prebiotics (FOS and GOS) that are naturally present in food will greatly assist research aimed at understanding their physiological role in the gut. © 2011 The Authors. Journal compilation © 2011 The British Dietetic Association Ltd.

An efficient and green method for regio- and chemo-selective Friedel–Crafts acylations using a deep eutectic mixture ([CholineCl][ZnCl2]3)

DEFF Research Database (Denmark)

Hoang, Tran Phuong; Nguyen, Hai Truong; Hansen, Poul Erik

2016-01-01

[CholineCl][ZnCl2]3, a deep eutectic solvent between choline chloride and ZnCl2, has been used as a dual function catalyst and green solvent for the Friedel–Crafts acylation of aromatic compounds instead of using the moisture-sensitive Lewis acids and volatile organic solvents. The reactions...... are performed with high yields under microwave irradiation with short reaction times for the synthesis of ketones. Interestingly, indole derivatives are regioselectively acylated in the 3-position under mild conditions with high yields without NH protection. Three new ketone products are synthesized. [Choline......Cl][ZnCl2]3 is easily synthesized from choline chloride and zinc chloride at a low cost, with easy purification and environmentally benign compounds. [CholineCl][ZnCl2]3 can be reused up to five times without loss of catalytic activity, making it ideal in industrial processes....

Two novel variants of human medium chain acyl-CoA dehydrogenase (MCAD). K364R, a folding mutation, and R256T, a catalytic-site mutation resulting in a well-folded but totally inactive protein

DEFF Research Database (Denmark)

O'Reilly, Linda P; Andresen, Brage S; Engel, Paul C

2005-01-01

was again totally inactive. Neither mutant showed marked depletion of FAD. The pure K364R protein was considerably less thermostable than wild-type MCAD. Western blots indicated that, although the R256T mutant protein is less thermostable than normal MCAD, it is much more stable than K364R. Though......Two novel rare mutations, MCAD approximately 842G-->C (R256T) and MCAD approximately 1166A-->G (K364R), have been investigated to assess how far the biochemical properties of the mutant proteins correlate with the clinical phenotype of medium chain acyl-CoA dehydrogenase (MCAD) deficiency. When...... the gene for K364R was overexpressed in Escherichia coli, the synthesized mutant protein only exhibited activity when the gene for chaperonin GroELS was co-overexpressed. Levels of activity correlated with the amounts of native MCAD protein visible in western blots. The R256T mutant, by contrast, displayed...

Genes involved in long-chain alkene biosynthesis in Micrococcus luteus.

Science.gov (United States)

Beller, Harry R; Goh, Ee-Been; Keasling, Jay D

2010-02-01

Aliphatic hydrocarbons are highly appealing targets for advanced cellulosic biofuels, as they are already predominant components of petroleum-based gasoline and diesel fuels. We have studied alkene biosynthesis in Micrococcus luteus ATCC 4698, a close relative of Sarcina lutea (now Kocuria rhizophila), which 4 decades ago was reported to biosynthesize iso- and anteiso-branched, long-chain alkenes. The underlying biochemistry and genetics of alkene biosynthesis were not elucidated in those studies. We show here that heterologous expression of a three-gene cluster from M. luteus (Mlut_13230-13250) in a fatty acid-overproducing Escherichia coli strain resulted in production of long-chain alkenes, predominantly 27:3 and 29:3 (no. carbon atoms: no. C=C bonds). Heterologous expression of Mlut_13230 (oleA) alone produced no long-chain alkenes but unsaturated aliphatic monoketones, predominantly 27:2, and in vitro studies with the purified Mlut_13230 protein and tetradecanoyl-coenzyme A (CoA) produced the same C(27) monoketone. Gas chromatography-time of flight mass spectrometry confirmed the elemental composition of all detected long-chain alkenes and monoketones (putative intermediates of alkene biosynthesis). Negative controls demonstrated that the M. luteus genes were responsible for production of these metabolites. Studies with wild-type M. luteus showed that the transcript copy number of Mlut_13230-13250 and the concentrations of 29:1 alkene isomers (the dominant alkenes produced by this strain) generally corresponded with bacterial population over time. We propose a metabolic pathway for alkene biosynthesis starting with acyl-CoA (or-ACP [acyl carrier protein]) thioesters and involving decarboxylative Claisen condensation as a key step, which we believe is catalyzed by OleA. Such activity is consistent with our data and with the homology (including the conserved Cys-His-Asn catalytic triad) of Mlut_13230 (OleA) to FabH (beta-ketoacyl-ACP synthase III), which

Degradation of amino acids to short-chain fatty acids in humans. An in vitro study

DEFF Research Database (Denmark)

Rasmussen, H S; Holtug, K; Mortensen, P B

1988-01-01

Short-chain fatty acids (SCFA) originate mainly in the colon through bacterial fermentation of polysaccharides. To test the hypothesis that SCFA may originate from polypeptides as well, the production of these acids from albumin and specific amino acids was examined in a faecal incubation system....... Albumin was converted to all C2-C5-fatty acids, whereas amino acids generally were converted to specific SCFA, most often through the combination of a deamination and decarboxylation of the amino acids, although more complex processes also took place. This study indicates that a part of the intestinal...

Structured medium and long chain triglycerides show short-term increases in fat oxidation, but no changes in adiposity in men.

Science.gov (United States)

Roynette, Catherine E; Rudkowska, Iwona; Nakhasi, Dilip K; Jones, Peter J H

2008-05-01

Medium chain triglycerides (MCT) have been suggested as modulators of human energy expenditure (EE) and thus may influence total and regional body fat distribution. To investigate in overweight men the effects of structured medium and long chain triglycerides on EE, substrate oxidation and body adiposity, compared to extra virgin olive oil (OO). In a 6 week single-blind crossover study, 23 overweight men were randomly assigned to consume a standard high-fat diet of which 75% total fat was provided as either structured medium and long chain triglycerides referred to as structured oil (StO), or OO. EE and body composition were measured using indirect calorimetry and magnetic resonance imaging, respectively, at weeks 1 and 6 of each phase. Body weight decreased (pstructured medium and long chain triglyceride oil increases short-term fat oxidation but fails to modulate body weight or adiposity through a change in EE.

pHP-Tethered N-Acyl Carbamate: A Photocage for Nicotinamide.

Science.gov (United States)

Salahi, Farbod; Purohit, Vatsal; Ferraudi, Guillermo; Stauffacher, Cynthia; Wiest, Olaf; Helquist, Paul

2018-05-04

The synthesis of a new photocaged nicotinamide having an N-acyl carbamate linker and a p-hydroxyphenacyl (pHP) chromophore is described. The photophysical and photochemical studies showed an absorption maximum at λ = 330 nm and a quantum yield for release of 11% that are dependent upon both pH and solvent. While the acyl carbamate releases nicotinamide efficiently, a simpler amide linker was inert to photocleavage. This photocaged nicotinamide has significant advantages with respect to quantum yield, absorbance wavelength, rate of release, and solubility that make it the first practical example of a photocaged amide.

Diagnostic potential of stored dried blood spots for inborn errors of metabolism: a metabolic autopsy of medium-chain acyl-CoA dehydrogenase deficiency.

Science.gov (United States)

Kaku, Noriyuki; Ihara, Kenji; Hirata, Yuichiro; Yamada, Kenji; Lee, Sooyoung; Kanemasa, Hikaru; Motomura, Yoshitomo; Baba, Haruhisa; Tanaka, Tamami; Sakai, Yasunari; Maehara, Yoshihiko; Ohga, Shouichi

2018-05-02

It is estimated that 1-5% of sudden infant death syndrome (SIDS) cases might be caused by undiagnosed inborn errors of metabolism (IEMs); however, the postmortem identification of IEMs remains difficult. This study aimed to evaluate the usefulness of dried blood spots (DBSs) stored after newborn screening tests as a metabolic autopsy to determine the causes of death in infants and children who died suddenly and unexpectedly. Infants or toddlers who had suddenly died without a definite diagnosis between July 2008 and December 2012 at Kyushu University Hospital in Japan were enrolled in this study. Their Guthrie cards, which had been stored for several years at 4-8°C, were used for an acylcarnitine analysis by tandem mass spectrometry to identify inborn errors of metabolism. Fifteen infants and children who died at less than 2 years of age and for whom the cause of death was unknown were enrolled for the study. After correcting the C0 and C8 values assuming the hydrolysation of acylcarnitine in the stored DBSs, the corrected C8 value of one case just exceeded the cut-off level for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency screening. Genetic and biochemical analyses confirmed this patient to have MCAD deficiency. DBSs stored after newborn screening tests are a promising tool for metabolic autopsy. The appropriate compensation of acylcarnitine data and subsequent genetic and biochemical analyses are essential for the postmortem diagnosis of inborn errors of metabolism. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Solution Structure of 4′-Phosphopantetheine - GmACP3 from Geobacter metallireducens: A Specialized Acyl Carrier Protein with Atypical Structural Features and a Putative Role in Lipopolysaccharide Biosynthesis†

Science.gov (United States)

Ramelot, Theresa A.; Smola, Matthew J.; Lee, Hsiau-Wei; Ciccosanti, Colleen; Hamilton, Keith; Acton, Thomas B.; Xiao, Rong; Everett, John K.; Prestegard, James H.; Montelione, Gaetano T.; Kennedy, Michael A.

2011-01-01

GmACP3 from Geobacter metallireducens is a specialized acyl carrier protein (ACP) whose gene, gmet_2339, is located near genes encoding many proteins involved in lipopolysaccharide (LPS) biosynthesis, indicating a likely function for GmACP3 in LPS production. By overexpression in Escherichia coli, about 50% holo-GmACP3 and 50% apo-GmACP3 were obtained. Apo-GmACP3 exhibited slow precipitation and non-monomeric behavior by 15N NMR relaxation measurements. Addition of 4′-phosphopantetheine (4′-PP) via enzymatic conversion by E. coli holo-ACP synthase, resulted in stable >95% holo-GmACP3 that was characterized as monomeric by 15N relaxation measurements and had no indication of conformational exchange. We have determined a high-resolution solution structure of holo-GmACP3 by standard NMR methods, including refinement with two sets of NH residual dipolar couplings, allowing for a detailed structural analysis of the interactions between 4′-PP and GmACP3. Whereas the overall four helix bundle topology is similar to previously solved ACP structures, this structure has unique characteristics, including an ordered 4′-PP conformation that places the thiol at the entrance to a central hydrophobic cavity near a conserved hydrogen-bonded Trp-His pair. These residues are part of a conserved WDSLxH/N motif found in GmACP3 and it’s orthologs. The helix locations and the large hydrophobic cavity are more similar to medium- and long-chain acyl-ACPs than to other apo- and holo-ACP structures. Taken together, structural characterization along with bioinformatic analysis of nearby genes suggest that GmACP3 is involved in lipid A acylation, possibly by atypical long-chain hydroxy fatty acids, and potentially involved in synthesis of secondary metabolites. PMID:21235239

Histone deacetylase inhibition and dietary short-chain Fatty acids.

Science.gov (United States)

Licciardi, Paul V; Ververis, Katherine; Karagiannis, Tom C

2011-01-01

Changes in diet can also have dramatic effects on the composition of gut microbiota. Commensal bacteria of the gastrointestinal tract are critical regulators of health and disease by protecting against pathogen encounter whilst also maintaining immune tolerance to certain allergens. Moreover, consumption of fibre and vegetables typical of a non-Western diet generates substantial quantities of short-chain fatty acids (SCFAs) which have potent anti-inflammatory properties. Dietary interventions such as probiotic supplementation have been investigated for their pleiotropic effects on microbiota composition and immune function. Probiotics may restore intestinal dysbiosis and improve clinical disease through elevated SCFA levels in the intestine. Although the precise mechanisms by which such dietary factors mediate these effects, SCFA metabolites such as butyrate also function as histone deacetylase inhibitors (HDACi), that can act on the epigenome through chromatin remodeling changes. The aim of this review is to provide an overview of HDAC enzymes and to discuss the biological effects of HDACi. Further, we discuss the important relationship between diet and the balance between health and disease and how novel dietary interventions such as probiotics could be alternative approach for the prevention and/or treatment of chronic inflammatory disease through modulation of the intestinal microbiome.

Expansion, retention and loss in the Acyl-CoA synthetase "Bubblegum" (Acsbg) gene family in vertebrate history.

Science.gov (United States)

Lopes-Marques, Mónica; Machado, André M; Ruivo, Raquel; Fonseca, Elza; Carvalho, Estela; Castro, L Filipe C

2018-07-20

Fatty acids (FAs) constitute a considerable fraction of all lipid molecules with a fundamental role in numerous physiological processes. In animals, the majority of complex lipid molecules are derived from the transformation of FAs through several biochemical pathways. Yet, for FAs to enroll in these pathways they require an activation step. FA activation is catalyzed by the rate limiting action of Acyl-CoA synthases. Several Acyl-CoA enzyme families have been previously described and classified according to the chain length of FAs they process. Here, we address the evolutionary history of the ACSBG gene family which activates, FAs with >16 carbons. Currently, two different ACSBG gene families, ACSBG1 and ACSBG2, are recognized in vertebrates. We provide evidence that a wider and unequal ACSBG gene repertoire is present in vertebrate lineages. We identify a novel ACSBG-like gene lineage which occurs specifically in amphibians, ray finned fishes, coelacanths and cartilaginous fishes named ACSBG3. Also, we show that the ACSBG2 gene lineage duplicated in the Theria ancestor. Our findings, thus offer a far richer understanding on FA activation in vertebrates and provide key insights into the relevance of comparative and functional analysis to perceive physiological differences, namely those related with lipid metabolic pathways. Copyright © 2018 Elsevier B.V. All rights reserved.

Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C Cross-Coupling.

Science.gov (United States)

Szostak, Roman; Shi, Shicheng; Meng, Guangrong; Lalancette, Roger; Szostak, Michal

2016-09-02

Amide N-C(O) bonds are generally unreactive in cross-coupling reactions employing low-valent transition metals due to nN → π*C═O resonance. Herein we demonstrate that N-acyl-tert-butyl-carbamates (Boc) and N-acyl-tosylamides (Ts), two classes of acyclic amides that have recently enabled the development of elusive amide bond N-C cross-coupling reactions with organometallic reagents, are intrinsically twisted around the N-C(O) axis. The data have important implications for the design of new amide cross-coupling reactions with the N-C(O) amide bond cleavage as a key step.

Markov Chain Modelling for Short-Term NDVI Time Series Forecasting

Directory of Open Access Journals (Sweden)

Stepčenko Artūrs

2016-12-01

Full Text Available In this paper, the NDVI time series forecasting model has been developed based on the use of discrete time, continuous state Markov chain of suitable order. The normalised difference vegetation index (NDVI is an indicator that describes the amount of chlorophyll (the green mass and shows the relative density and health of vegetation; therefore, it is an important variable for vegetation forecasting. A Markov chain is a stochastic process that consists of a state space. This stochastic process undergoes transitions from one state to another in the state space with some probabilities. A Markov chain forecast model is flexible in accommodating various forecast assumptions and structures. The present paper discusses the considerations and techniques in building a Markov chain forecast model at each step. Continuous state Markov chain model is analytically described. Finally, the application of the proposed Markov chain model is illustrated with reference to a set of NDVI time series data.

Retention of short chain fatty acids under drying and storage conditions

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Alexandre Santos Souza

2011-09-01

Full Text Available Cheese whey permeate was used as a substrate for the fermentation of Propionibacterium freudenreichi PS1 for the production of short chain fatty acids, components of the bio-aroma of Swiss cheese. The liquid bio-aroma was encapsulated by spray drying under different conditions of air inlet temperature and feed rate. A study was carried out on the stability of the bio-aroma during storage in laminated packages at 30 °C for 96 days using the product showing the greatest retention of acetic and propionic acids. The results showed that the best drying conditions were an air entrance temperature of 180 °C and a feed rate of 24 g/min resulting in particles with a smooth surface and few invaginations and micro-fissures. However, 72% of the acetic acid and 80% of the propionic acid were lost during storage showing that the wall material used was inadequate to guarantee product stability.

Bifidobacteria, Lactobacilli, and Short Chain Fatty Acids of Vegetarians and Omnivores

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Bunešová Věra

2017-03-01

Full Text Available The intestinal microbiota represents the largest and the most complex microbial community inhabiting the human body. Bifidobacteria and lactobacilli represent important commensal bacteria with the ability to utilize complex carbohydrates. The main fermentation products from the breakdown of complex dietary carbohydrates are short chain fatty acids (SCFAs. We examined faecal samples of vegetarians (n = 10 and conventional omnivores (n = 10 to evaluate the counts and occurrence of cultivable bacteria, especially bifidobacteria and lactobacilli, using cultivation on selective media, and matrix-assisted laser desorption/ionization time-of-flight. Moreover, concentrations and molar proportion of SCFAs in faecal samples were measured. Total counts of Gram-negative anaerobic bacteria were significantly lower (P 0.05 between the diet groups. In total, six Bifidobacterium spp. and thirteen Lactobacillus spp. were detected via culture-dependent methods. Bifidobacteria counts and species composition in faecal samples of both groups were found to be relatively similar, regardless of the diet. Lactobacillus species varied more by individual diet.

Crystallization in melts of short, semiflexible hard polymer chains: An interplay of entropies and dimensions

Science.gov (United States)

Shakirov, T.; Paul, W.

2018-04-01

What is the thermodynamic driving force for the crystallization of melts of semiflexible polymers? We try to answer this question by employing stochastic approximation Monte Carlo simulations to obtain the complete thermodynamic equilibrium information for a melt of short, semiflexible polymer chains with purely repulsive nonbonded interactions. The thermodynamics is obtained based on the density of states of our coarse-grained model, which varies by up to 5600 orders of magnitude. We show that our polymer melt undergoes a first-order crystallization transition upon increasing the chain stiffness at fixed density. This crystallization can be understood by the interplay of the maximization of different entropy contributions in different spatial dimensions. At sufficient stiffness and density, the three-dimensional orientational interactions drive the orientational ordering transition, which is accompanied by a two-dimensional translational ordering transition in the plane perpendicular to the chains resulting in a hexagonal crystal structure. While the three-dimensional ordering can be understood in terms of Onsager theory, the two-dimensional transition can be understood in terms of the liquid-hexatic transition of hard disks. Due to the domination of lateral two-dimensional translational entropy over the one-dimensional translational entropy connected with columnar displacements, the chains form a lamellar phase. Based on this physical understanding, orientational ordering and translational ordering should be separable for polymer melts. A phenomenological theory based on this understanding predicts a qualitative phase diagram as a function of volume fraction and stiffness in good agreement with results from the literature.

Heterologous co-expression of accA, fabD, and thioesterase genes for improving long-chain fatty acid production in Pseudomonas aeruginosa and Escherichia coli.

Science.gov (United States)

Lee, Sunhee; Jeon, Eunyoung; Jung, Yeontae; Lee, Jinwon

2012-05-01

The goal of the present study was to increase the content of intracellular long-chain fatty acids in two bacterial strains, Pseudomonas aeruginosa PA14 and Escherichia coli K-12 MG1655, by co-overexpressing essential enzymes that are involved in the fatty acid synthesis metabolic pathway. Recently, microbial fatty acids and their derivatives have been receiving increasing attention as an alternative source of fuel. By introducing two genes (accA and fabD) of P. aeruginosa into the two bacterial strains and by co-expressing with them the fatty acyl-acyl carrier protein thioesterase gene of Streptococcus pyogenes (strain MGAS10270), we have engineered recombinant strains that are efficient producers of long-chain fatty acids (C16 and C18). The recombinant strains exhibit a 1.3-1.7-fold increase in the production of long-chain fatty acids over the wild-type strains. To enhance the production of total long-chain fatty acids, we researched the carbon sources for optimized culture conditions and results were used for post-culture incubation period. E. coli SGJS17 (containing the accA, fabD, and thioesterase genes) produced the highest content of intracellular total fatty acids; in particular, the unsaturated fatty acid content was about 20-fold higher than that in the wild-type E. coli.

Different effects of short- and long-chained fructans on large intestinal physiology and carcinogen-induced aberrant crypt foci in rats

DEFF Research Database (Denmark)

Poulsen, Morten; Molck, Anne-Marie; Jacobsen, Bodil Lund

2002-01-01

Inulin-type fructans, which are nondigestible carbohydrates, have been shown to modulate the number of induced preneoplastic lesions in the colon as well as the colonic microflora in laboratory animals. The present study was designed to investigate the effect of a short- and long-chained inulin...

Comprehensive in Vitro Analysis of Acyltransferase Domain Exchanges in Modular Polyketide Synthases and Its Application for Short-Chain Ketone Production

DEFF Research Database (Denmark)

Yuzawa, Satoshi; Deng, Kai; Wang, George

2017-01-01

AT domain replacements in most type I PKS modules. To further demonstrate the utility of the optimized AT domain boundary, we have constructed hybrid PKSs to produce industrially important short-chain ketones. Our in vitro and in vivo analysis demonstrated production of predicted ketones without significant...

Phosphatidylserine-stimulated production of N-acyl-phosphatidylethanolamines by Ca2+-dependent N-acyltransferase.

Science.gov (United States)

Hussain, Zahir; Uyama, Toru; Kawai, Katsuhisa; Binte Mustafiz, Smriti Sultana; Tsuboi, Kazuhito; Araki, Nobukazu; Ueda, Natsuo

2018-05-01

N-acyl-phosphatidylethanolamine (NAPE) is known to be a precursor for various bioactive N-acylethanolamines including the endocannabinoid anandamide. NAPE is produced in mammals through the transfer of an acyl chain from certain glycerophospholipids to phosphatidylethanolamine (PE) by Ca 2+ -dependent or -independent N-acyltransferases. The ε isoform of mouse cytosolic phospholipase A 2 (cPLA 2 ε) was recently identified as a Ca 2+ -dependent N-acyltransferase (Ca-NAT). In the present study, we first showed that two isoforms of human cPLA 2 ε function as Ca-NAT. We next purified both mouse recombinant cPLA 2 ε and its two human orthologues to examine their catalytic properties. The enzyme absolutely required Ca 2+ for its activity and the activity was enhanced by phosphatidylserine (PS). PS enhanced the activity 25-fold in the presence of 1 mM CaCl 2 and lowered the EC 50 value of Ca 2+ >8-fold. Using a PS probe, we showed that cPLA 2 ε largely co-localizes with PS in plasma membrane and organelles involved in the endocytic pathway, further supporting the interaction of cPLA 2 ε with PS in living cells. Finally, we found that the Ca 2+ -ionophore ionomycin increased [ 14 C]NAPE levels >10-fold in [ 14 C]ethanolamine-labeled cPLA 2 ε-expressing cells while phospholipase A/acyltransferase-1, acting as a Ca 2+ -independent N-acyltransferase, was insensitive to ionomycin for full activity. In conclusion, PS potently stimulated the Ca 2+ -dependent activity and human cPLA 2 ε isoforms also functioned as Ca-NAT. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of heterologous expression of acyl-CoA-binding protein on acyl-CoA level and composition in yeast

DEFF Research Database (Denmark)

Mandrup, S; Jepsen, R; Skøtt, H

1993-01-01

We have expressed a bovine synthetic acyl-CoA-binding protein (ACBP) gene in yeast (Saccharomyces cerevisiae) under the control of the GAL1 promoter. The heterologously expressed bovine ACBP constituted up to 6.4% of total cellular protein and the processing was identical with that of native bovi...

Mild and Highly Efficient Copper(I Inspired Acylation of Alcohols and Polyols

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Enoch A. Mensah

2017-01-01

Full Text Available A new and highly efficient method mediated by tetrakis(acetonitrilecopper(I triflate for activating both simple and highly hindered anhydrides in the acylation of alcohols and polyols is described. This new acylation method is mild and mostly proceeds at room temperature with low catalyst loading. The method is versatile and has been extended to a wide variety of different alcohol substrates to afford the corresponding ester products in good to excellent yields.

Synthesis of 1-isopropyl-3-acyl-5-methyl-benzimidazolone Derivatives and Their Antimicrobial Activity

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Shaopeng Wei

2013-03-01

Full Text Available A series of N-acylated analogues of 1-isopropyl-3-acyl-5-methyl-benzimidazolone were synthesized. Bioassay results indicated that analogues 5-07 and 5-19 exhibited the most potency against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Analogues 5-02, 5-07, 5-12, 5-15, 5-19, 5-20 and 5-25 could effectively inhibit the spore germination of Botrytis cinerea. The relationship between structure and their antimicrobial activity (SAR has also been discussed according to aliphatic acids and aromatic acids derivatives, respectively. This implied that the N-acylated derivatives of 5-methyl-benzimidazolone might be potential antimicrobial agents.

The 625G>A SCAD gene variant is common but not associated with increased C4-carnitine in newborn blood spots

NARCIS (Netherlands)

van Maldegem, B. T.; Waterham, H. R.; Duran, M.; van der Vlies, M.; van Woerden, C. S.; Bobu, L. L.; Wanders, R. J. A.; Wijburg, F. A.

2005-01-01

The 625G>A variant of the short-chain acyl-CoA dehydrogenase (SCAD) gene is considered to confer susceptibility for developing 'clinical SCAD deficiency' and appears to be common in the general population. To determine the frequency of the 625G>A variant in The Netherlands, we analysed 1036

Enantiocomplementary Yarrowia lipolytica Oxidoreductases: Alcohol Dehydrogenase 2 and Short Chain Dehydrogenase/Reductase

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Margit Winkler

2013-08-01

Full Text Available Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisiae. A preference for secondary compared to primary alcohols in oxidation direction was observed for YlADH2. 2-Octanone was investigated in reduction mode in detail. Remarkably, YlADH2 displays perfect (S-selectivity and together with a highly (R-selective short chain dehydrogenase/ reductase from Yarrowia lipolytica it is possible to access both enantiomers of 2-octanol in >99% ee with Yarrowia lipolytica oxidoreductases.

Enantiocomplementary Yarrowia lipolytica Oxidoreductases: Alcohol Dehydrogenase 2 and Short Chain Dehydrogenase/Reductase.

Science.gov (United States)

Napora-Wijata, Kamila; Strohmeier, Gernot A; Sonavane, Manoj N; Avi, Manuela; Robins, Karen; Winkler, Margit

2013-08-12

Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisiae. A preference for secondary compared to primary alcohols in oxidation direction was observed for YlADH2. 2-Octanone was investigated in reduction mode in detail. Remarkably, YlADH2 displays perfect (S)-selectivity and together with a highly (R)-selective short chain dehydrogenase/ reductase from Yarrowia lipolytica it is possible to access both enantiomers of 2-octanol in >99% ee with Yarrowia lipolytica oxidoreductases.

Density functional theory studies on the nano-scaled composites consisted of graphene and acyl hydrazone molecules

Science.gov (United States)

Ren, J. L.; Zhou, L.; Lv, Z. C.; Ding, C. H.; Wu, Y. H.; Bai, H. C.

2016-07-01

Graphene, which is the first obtained single atomic layer 2D materials, has drawn a great of concern in nano biotechnology due to the unique property. On one hand, acyl hydrazone compounds belonging to the Schif bases have aroused considerable attention in medicine, pharmacy, and analytical reagent. However, few understanding about the interaction between graphene and acyl hydrazone molecules is now available. And such investigations are much crucial for the applications of these new nano-scaled composites. The current work revealed theoretical investigations on the nano-scaled composites built by acyl hydrazone molecules loaded on the surface of graphene. The relative energy, electronic property and the interaction between the counterparts of graphene/acyl hydrazone composites are investigated based on the density functional theory calculations. According to the obtained adsorption energy, the formation of the nano-scaled composite from the isolated graphene and acyl hydrazone molecule is exothermic, and thus it is energetically favorable to form these nano composites in viewpoint of total energy change. The frontier molecular orbital for the nano composite is mainly distributed at the graphene part, leading to that the energy levels of the frontier molecular orbital of the nano composites are very close to that of isolated graphene. Moreover, the counterpart interaction for the graphene/acyl hydrazone composites is also explored based on the discussions of orbital hybridization, charge redistribution and Van der Waals interaction.

Turnover and metabolism of phosphatidylglycerol acyl moieties in E. coli

International Nuclear Information System (INIS)

Cooper, C.L.; Rock, C.O.

1987-01-01

Fatty acids synthesized in mutants (plsB) blocked in de novo phospholipid biosynthesis were preferentially transferred to phosphatidylglycerol (PtdGro). The ratio of phospholipid species labeled with 32 P and [ 3 H]acetate in the absence of glycerol-3-P acyltransferase activity indicated that [ 3 H]acetate incorporation into PtdGro was due to fatty acid turnover. The magnitude of the turnover process was difficult to estimate due to a significant contraction of the acetyl-CoA pool following the inhibition of phospholipid synthesis. A possible connection between PtdGro turnover and protein acylation was investigated in an E. coli strain containing a lipoprotein expression vector. Cells were prelabeled with [ 3 H]acetate and lipoprotein expression was induced concomitant with the addition of exogenous [ 14 C]-palmitate. [ 14 C] Palmitate was assimilated into the l-position of phosphatidylethanolamine and transferred to the amino terminus of the lipoprotein. In contrast, the ester-linked lipoprotein fatty acids and PtdGro were not enriched in carbon-14 implying a metabolic relationship between these two pools. The data suggest that turnover of PtdGro acyl moieties is related to protein acylation, but a direct link between the two processes remains to be established

Development of double chain phosphatidylcholine functionalized polymeric monoliths for immobilized artificial membrane chromatography.

Science.gov (United States)

Wang, Qiqin; Peng, Kun; Chen, Weijia; Cao, Zhen; Zhu, Peijie; Zhao, Yumei; Wang, Yuqiang; Zhou, Haibo; Jiang, Zhengjin

2017-01-06

This study described a simple synthetic methodology for preparing biomembrane mimicking monolithic column. The suggested approach not only simplifies the preparation procedure but also improves the stability of double chain phosphatidylcholine (PC) functionalized monolithic column. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and nano-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained on this double chain PC functionalized monolithic column. It is worth noting that the resulting polymeric monolith exhibits great potential as a useful alternative of commercial immobilized artificial membrane (IAM) columns for in vitro predication of drug-membrane interactions. Furthermore, the comparative study of both double chain and single chain PC functionalized monoliths indicates that the presence or absence of glycerol backbone and the number of acyl chains are not decisive for the predictive ability of IAM monoliths on drug-membrane interactions. This novel PC functionalized monolithic column also exhibited good selectivity for a protein mixture and a set of pharmaceutical compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of some characteristics of polyhydroxy milkweed triglycerides and their acylated derivatives in relation to lubricity.

Science.gov (United States)

Harry-O'kuru, Rogers E; Biresaw, Girma; Cermak, Steven C; Gordon, Sherald H; Vermillion, Karl

2011-05-11

Most industrial lubricants are derived from nonrenewable petroleum-based sources. As useful as these lubricants are, their unintended consequences are the pollution of the Earth's environment as a result of the slow degradation of the spent materials. Native seed oils, on the other hand, are renewable and are also biodegradable in the environment, but these oils often suffer a drawback in having lower thermal stability and a shorter shelf life because of the intrinsic -C═C- unsaturation in their structures. This drawback can be overcome, yet the inherent biodegradative property retained, by appropriate derivatization of the oil. Pursuant to this, this study investigated derivatized polyhydroxy milkweed oil to assess its suitability as lubricant. The milkweed plant is a member of the Asclepiadaceae, a family with many genera including the common milkweeds, Asclepias syriaca L., Asclepias speciosa L., Asclepias tuberosa L., etc. The seeds of these species contain mainly C-18 triglycerides that are highly unsaturated, 92%. The olefinic character of this oil has been chemically modified by generating polyhydroxy triglycerides (HMWO) that show high viscosity and excellent moisturizing characteristics. In this work, HMWO have been chemically modified by esterifying their hydroxyl groups with acyl groups of various chain lengths (C2-C5). The results of investigation into the effect of the acyl derivatives' chemical structure on kinematic and dynamic viscosity, oxidation stability, cold-flow (pour point, cloud point) properties, coefficient of friction, wear, and elastohydrodynamic film thickness are discussed.

The acyl-CoA binding protein is required for normal epidermal barrier function in mice

DEFF Research Database (Denmark)

Bloksgaard, Maria; Bek, Signe; Marcher, Ann-Britt

2012-01-01

(+/+) and ACBP(-/-) mice showed very similar composition, except for a significant and specific decrease in the very long chain free fatty acids (VLC-FFA) in stratum corneum of ACBP(-/-) mice. This finding indicates that ACBP is critically involved in the processes that lead to production of stratum corneum VLC......The acyl-CoA binding protein (ACBP) is a 10 kDa intracellular protein expressed in all eukaryotic species. Mice with targeted disruption of Acbp (ACBP(-/-) mice) are viable and fertile but present a visible skin and fur phenotype characterized by greasy fur and development of alopecia and scaling...... with age. Morphology and development of skin and appendages are normal in ACBP(-/-) mice; however, the stratum corneum display altered biophysical properties with reduced proton activity and decreased water content. Mass spectrometry analyses of lipids from epidermis and stratum corneum of ACBP...

Use of isothermal titration calorimetry to study the interaction of short-chain alcohols with lipid membranes

DEFF Research Database (Denmark)

Trandum, Christa; Westh-Andersen, Peter; Jørgensen, Kent

1999-01-01

of short-chain alcohols on Lipid bilayers. isothermal titration calorimetry (ITC) has been used to determine the energy involved in the association of the alcohols with lipid bilayers. Pure unilamellar DMPC liposomes and DMPC liposomes incorporated with different amounts of cholesterol, sphingomyelin...... dependent on the lipid bilayer composition. In the presence of high concentrations of cholesterol, the binding enthalpy of ethanol is decreased, whereas the presence of ceramides enhances the enthalpic response of the lipid bilayer to ethanol. Isothermal titration calorimetry offers a new methodology...

Serum Levels of Acyl-Carnitines along the Continuum from Normal to Alzheimer's Dementia

Science.gov (United States)

Sapere, Nadia; La Marca, Giancarlo; Angiolillo, Antonella; Vitale, Michela; Corbi, Graziamaria; Scapagnini, Giovanni; Intrieri, Mariano; Russo, Claudio

2016-01-01

This study aimed to determine the serum levels of free L-carnitine, acetyl-L-carnitine and 34 acyl-L-carnitine in healthy subjects and in patients with or at risk of Alzheimer’s disease. Twenty-nine patients with probable Alzheimer’s disease, 18 with mild cognitive impairment of the amnestic type, 24 with subjective memory complaint and 46 healthy subjects were enrolled in the study, and the levels of carnitine and acyl-carnitines were measured by tandem mass spectrometry. The concentrations of acetyl-L-carnitine progressively decreased passing from healthy subjects group (mean±SD, 5.6±1.3 μmol/L) to subjective memory complaint (4.3±0.9 μmol/L), mild cognitive impairment (4.0±0.53 μmol/L), up to Alzheimer’s disease (3.5±0.6 μmol/L) group (p<0.001). The differences were significant for the comparisons: healthy subjects vs. subjective memory complaint, mild cognitive impairment or Alzheimer’s disease group; and subjective memory complaint vs. Alzheimer’s disease group. Other acyl-carnitines, such as malonyl-, 3-hydroxyisovaleryl-, hexenoyl-, decanoyl-, dodecanoyl-, dodecenoyl-, myristoyl-, tetradecenoyl-, hexadecenoyl-, stearoyl-, oleyl- and linoleyl-L-carnitine, showed a similar decreasing trend, passing from healthy subjects to patients at risk of or with Alzheimer’s disease. These results suggest that serum acetyl-L-carnitine and other acyl-L-carnitine levels decrease along the continuum from healthy subjects to subjective memory complaint and mild cognitive impairment subjects, up to patients with Alzheimer’s disease, and that the metabolism of some acyl-carnitines is finely connected among them. These findings also suggest that the serum levels of acetyl-L-carnitine and other acyl-L-carnitines could help to identify the patients before the phenotype conversion to Alzheimer’s disease and the patients who would benefit from the treatment with acetyl-L-carnitine. However, further validation on a larger number of samples in a longitudinal

Serum Levels of Acyl-Carnitines along the Continuum from Normal to Alzheimer's Dementia.

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Adriana Cristofano

Full Text Available This study aimed to determine the serum levels of free L-carnitine, acetyl-L-carnitine and 34 acyl-L-carnitine in healthy subjects and in patients with or at risk of Alzheimer's disease. Twenty-nine patients with probable Alzheimer's disease, 18 with mild cognitive impairment of the amnestic type, 24 with subjective memory complaint and 46 healthy subjects were enrolled in the study, and the levels of carnitine and acyl-carnitines were measured by tandem mass spectrometry. The concentrations of acetyl-L-carnitine progressively decreased passing from healthy subjects group (mean±SD, 5.6±1.3 μmol/L to subjective memory complaint (4.3±0.9 μmol/L, mild cognitive impairment (4.0±0.53 μmol/L, up to Alzheimer's disease (3.5±0.6 μmol/L group (p<0.001. The differences were significant for the comparisons: healthy subjects vs. subjective memory complaint, mild cognitive impairment or Alzheimer's disease group; and subjective memory complaint vs. Alzheimer's disease group. Other acyl-carnitines, such as malonyl-, 3-hydroxyisovaleryl-, hexenoyl-, decanoyl-, dodecanoyl-, dodecenoyl-, myristoyl-, tetradecenoyl-, hexadecenoyl-, stearoyl-, oleyl- and linoleyl-L-carnitine, showed a similar decreasing trend, passing from healthy subjects to patients at risk of or with Alzheimer's disease. These results suggest that serum acetyl-L-carnitine and other acyl-L-carnitine levels decrease along the continuum from healthy subjects to subjective memory complaint and mild cognitive impairment subjects, up to patients with Alzheimer's disease, and that the metabolism of some acyl-carnitines is finely connected among them. These findings also suggest that the serum levels of acetyl-L-carnitine and other acyl-L-carnitines could help to identify the patients before the phenotype conversion to Alzheimer's disease and the patients who would benefit from the treatment with acetyl-L-carnitine. However, further validation on a larger number of samples in a longitudinal

DFT-based prediction of reactivity of short-chain alcohol dehydrogenase

Science.gov (United States)

Stawoska, I.; Dudzik, A.; Wasylewski, M.; Jemioła-Rzemińska, M.; Skoczowski, A.; Strzałka, K.; Szaleniec, M.

2017-06-01

The reaction mechanism of ketone reduction by short chain dehydrogenase/reductase, ( S)-1-phenylethanol dehydrogenase from Aromatoleum aromaticum, was studied with DFT methods using cluster model approach. The characteristics of the hydride transfer process were investigated based on reaction of acetophenone and its eight structural analogues. The results confirmed previously suggested concomitant transfer of hydride from NADH to carbonyl C atom of the substrate with proton transfer from Tyr to carbonyl O atom. However, additional coupled motion of the next proton in the proton-relay system, between O2' ribose hydroxyl and Tyr154 was observed. The protonation of Lys158 seems not to affect the pKa of Tyr154, as the stable tyrosyl anion was observed only for a neutral Lys158 in the high pH model. The calculated reaction energies and reaction barriers were calibrated by calorimetric and kinetic methods. This allowed an excellent prediction of the reaction enthalpies (R2 = 0.93) and a good prediction of the reaction kinetics (R2 = 0.89). The observed relations were validated in prediction of log K eq obtained for real whole-cell reactor systems that modelled industrial synthesis of S-alcohols.

Summer–winter concentrations and gas-particle partitioning of short chain chlorinated paraffins in the atmosphere of an urban setting

International Nuclear Information System (INIS)

Wang Thanh; Han Shanlong; Yuan Bo; Zeng Lixi; Li Yingming; Wang Yawei; Jiang Guibin

2012-01-01

Short chain chlorinated paraffins (SCCPs) are semi-volatile chemicals that are considered persistent in the environment, potential toxic and subject to long-range transport. This study investigates the concentrations and gas-particle partitioning of SCCPs at an urban site in Beijing during summer and wintertime. The total atmospheric SCCP levels ranged 1.9–33.0 ng/m 3 during wintertime. Significantly higher levels were found during the summer (range 112–332 ng/m 3 ). The average fraction of total SCCPs in the particle phase (φ) was 0.67 during wintertime but decreased significantly during the summer (φ = 0.06). The ten and eleven carbon chain homologues with five to eight chlorine atoms were the predominant SCCP formula groups in air. Significant linear correlations were found between the gas-particle partition coefficients and the predicted subcooled vapor pressures and octanol–air partition coefficients. The gas-particle partitioning of SCCPs was further investigated and compared with both the Junge–Pankow adsorption and K oa -based absorption models. - Highlights: ► Short chain chlorinated paraffins were investigated in air samples from Beijing. ► Higher levels of SCCPs were found in air during summertime than wintertime. ► Relevant physical–chemical properties were estimated by SPARC and EPI Suite. ► Obtained data were used to model the gas-particle partitioning of SCCPs. - Atmospheric levels and gas-particle partitioning of SCCPs in Beijing, China.

From Short Food Supply Chains to Sustainable Agriculture in Urban Food Systems: Food Democracy as a Vector of Transition

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Yuna Chiffoleau

2016-10-01

Full Text Available In industrialized nations, local food networks have generally been analyzed through alternative food systems, in spite of the fact that they are much more diverse than this would imply. In France, ‘short food chains’ are both a continuation of a long tradition and a recent trend which now extends beyond activists, to consumers and producers as well. This paper will explore the conditions under which these chains can change the practices and knowledge of ordinary actors in urban food systems, from producers to urban consumers and policy-makers, in the area of agriculture and sustainability. It will consider the case study of the creation and development of an urban open-air market which has been analyzed using intervention research with input from economic sociology. We will highlight how personal relations, which are encouraged by a participatory context, support the evolution of practices and knowledge. We will also illustrate how a system of produce labelling has emerged as a mediation resource, and has increased changes as well as participation within the re-territorialization of the urban food system. By describing a concrete expression of food democracy which is spreading in France via a free collective trademark, and by showing its role in the transition of ‘ordinary’ actors towards a more sustainable agriculture, this paper will shine new light onto local food chains as well as traditional short food chains, and will call for more research on the subject.

Proghrelin peptides: Desacyl ghrelin is a powerful inhibitor of acylated ghrelin, likely to impair physiological effects of acyl ghrelin but not of obestatin A study of pancreatic polypeptide secretion from mouse islets

DEFF Research Database (Denmark)

Kumar, Rajesh; Salehi, Albert; Rehfeld, Jens F

2010-01-01

Proghrelin, produced by the ghrelin (A-like) cells of the gastric mucosa, gives rise to cleavage products, including desacyl ghrelin, acyl ghrelin and obestatin. The products are thought to be secreted concomitantly. In an earlier study we found acyl ghrelin and obestatin, but not desacyl ghrelin......, to suppress the release of hormones from isolated islets of mouse and rat pancreas....

A Catalase-related Hemoprotein in Coral Is Specialized for Synthesis of Short-chain Aldehydes

Science.gov (United States)

Teder, Tarvi; Lõhelaid, Helike; Boeglin, William E.; Calcutt, Wade M.; Brash, Alan R.; Samel, Nigulas

2015-01-01

In corals a catalase-lipoxygenase fusion protein transforms arachidonic acid to the allene oxide 8R,9-epoxy-5,9,11,14-eicosatetraenoic acid from which arise cyclopentenones such as the prostanoid-related clavulones. Recently we cloned two catalase-lipoxygenase fusion protein genes (a and b) from the coral Capnella imbricata, form a being an allene oxide synthase and form b giving uncharacterized polar products (Lõhelaid, H., Teder, T., Tõldsepp, K., Ekins, M., and Samel, N. (2014) PloS ONE 9, e89215). Here, using HPLC-UV, LC-MS, and NMR methods, we identify a novel activity of fusion protein b, establishing its role in cleaving the lipoxygenase product 8R-hydroperoxy-eicosatetraenoic acid into the short-chain aldehydes (5Z)-8-oxo-octenoic acid and (3Z,6Z)-dodecadienal; these primary products readily isomerize in an aqueous medium to the corresponding 6E- and 2E,6Z derivatives. This type of enzymatic cleavage, splitting the carbon chain within the conjugated diene of the hydroperoxide substrate, is known only in plant cytochrome P450 hydroperoxide lyases. In mechanistic studies using 18O-labeled substrate and incubations in H218O, we established synthesis of the C8-oxo acid and C12 aldehyde with the retention of the hydroperoxy oxygens, consistent with synthesis of a short-lived hemiacetal intermediate that breaks down spontaneously into the two aldehydes. Taken together with our initial studies indicating differing gene regulation of the allene oxide synthase and the newly identified catalase-related hydroperoxide lyase and given the role of aldehydes in plant defense, this work uncovers a potential pathway in coral stress signaling and a novel enzymatic activity in the animal kingdom. PMID:26100625

Long chain fatty Acyl-CoA synthetase 4 is a biomarker for and mediator of hormone resistance in human breast cancer.

Directory of Open Access Journals (Sweden)

Xinyu Wu

Full Text Available The purpose of this study was to determine the role of long-chain fatty acyl-CoA synthetase 4 (ACSL4 in breast cancer. Public databases were utilized to analyze the relationship between ACSL4 mRNA expression and the presence of steroid hormone and human epidermal growth factor receptor 2 (HER2 in both breast cancer cell lines and tissue samples. In addition, cell lines were utilized to assess the consequences of either increased or decreased levels of ACSL4 expression. Proliferation, migration, anchorage-independent growth and apoptosis were used as biological end points. Effects on mRNA expression and signal transduction pathways were also monitored. A meta-analysis of public gene expression databases indicated that ACSL4 expression is positively correlated with a unique subtype of triple negative breast cancer (TNBC, characterized by the absence of androgen receptor (AR and therefore referred to as quadruple negative breast cancer (QNBC. Results of experiments in breast cancer cell lines suggest that simultaneous expression of ACSL4 and a receptor is associated with hormone resistance. Forced expression of ACSL4 in ACSL4-negative, estrogen receptor α (ER-positive MCF-7 cells resulted in increased growth, invasion and anchorage independent growth, as well as a loss of dependence on estrogen that was accompanied by a reduction in the levels of steroid hormone receptors. Sensitivity to tamoxifen, triacsin C and etoposide was also attenuated. Similarly, when HER2-positive, ACSL4-negative, SKBr3 breast cancer cells were induced to express ACSL4, the proliferation rate increased and the apoptotic effect of lapatinib was reduced. The growth stimulatory effect of ACSL4 expression was also observed in vivo in nude mice when MCF-7 control and ACSL4-expressing cells were utilized to induce tumors. Our data strongly suggest that ACSL4 can serve as both a biomarker for, and mediator of, an aggressive breast cancer phenotype.

RNA-Seq and Mass-Spectrometry-Based Lipidomics Reveal Extensive Changes of Glycerolipid Pathways in Brown Adipose Tissue in Response to Cold

DEFF Research Database (Denmark)

Marcher, Ann-Britt; Loft, Anne; Nielsen, Ronni

2015-01-01

involved in glycerophospholipid synthesis and fatty acid elongation. This is accompanied by significant changes in the acyl chain composition of triacylglycerols (TAGs) as well as subspecies-selective changes of acyl chains in glycerophospholipids. These results indicate that cold adaptation of BAT......Cold exposure greatly alters brown adipose tissue (BAT) gene expression and metabolism to increase thermogenic capacity. Here, we used RNA sequencing and mass-spectrometry-based lipidomics to provide a comprehensive resource describing the molecular signature of cold adaptation at the level...... of the transcriptome and lipidome. We show that short-term (3-day) cold exposure leads to a robust increase in expression of several brown adipocyte genes related to thermogenesis as well as the gene encoding the hormone irisin. However, pathway analysis shows that the most significantly induced genes are those...

S-acylation of SOD1, CCS, and a stable SOD1-CCS heterodimer in human spinal cords from ALS and non-ALS subjects.

Science.gov (United States)

Antinone, Sarah E; Ghadge, Ghanashyam D; Ostrow, Lyle W; Roos, Raymond P; Green, William N

2017-01-25

Previously, we found that human Cu, Zn-superoxide dismutase (SOD1) is S-acylated (palmitoylated) in vitro and in amyotrophic lateral sclerosis (ALS) mouse models, and that S-acylation increased for ALS-causing SOD1 mutants relative to wild type. Here, we use the acyl resin-assisted capture (acyl-RAC) assay to demonstrate S-acylation of SOD1 in human post-mortem spinal cord homogenates from ALS and non-ALS subjects. Acyl-RAC further revealed that endogenous copper chaperone for SOD1 (CCS) is S-acylated in both human and mouse spinal cords, and in vitro in HEK293 cells. SOD1 and CCS formed a highly stable heterodimer in human spinal cord homogenates that was resistant to dissociation by boiling, denaturants, or reducing agents and was not observed in vitro unless both SOD1 and CCS were overexpressed. Cysteine mutations that attenuate SOD1 maturation prevented the SOD1-CCS heterodimer formation. The degree of S-acylation was highest for SOD1-CCS heterodimers, intermediate for CCS monomers, and lowest for SOD1 monomers. Given that S-acylation facilitates anchoring of soluble proteins to cell membranes, our findings suggest that S-acylation and membrane localization may play an important role in CCS-mediated SOD1 maturation. Furthermore, the highly stable S-acylated SOD1-CCS heterodimer may serve as a long-lived maturation intermediate in human spinal cord.

Yoghurt from short supply chain: preliminary study of microbiological and physicochemical characteristics during shelf life

Directory of Open Access Journals (Sweden)

Virginia Carfora

2013-04-01

Full Text Available Yoghurt is one of very popular flavorful and healthful dairy product obtained by fermentation of lactic acid bacteria including Lactobacillus delbrueckii bulgaricus and Streptococcus thermophilus. Its production and consumption is growing continuously due to its therapeutic properties beside its high nutritive value. Thirty samples of yoghurt from short supply chain produced in 2 factory localized in Lazio region were analyzed with the aim of determining how certain microbiological and physicochemical characteristics change during their shelf life. Different types of yoghurt were studied: plain (12, fruit (14 and cereal yoghurt (4 produced with cow (8 and goat milk (22.The obtained results show: no presence of Enterobacteria, occasional presence of moulds and a considerable presence of yeasts. On the other hand, all the products analyzed have shown an almost constant amount of lactic acid bacteria during their shelf life. Lactic acid bacteria were identified by a biochemical and polymerase chain reaction assay. The presence of undesired microorganisms like yeasts was found. However, the quality of products was satisfying for the concentration of lactic acid bacteria detected in their shelf life.

Fatal hepatic short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase deficiency: clinical, biochemical, and pathological studies on three subjects with this recently identified disorder of mitochondrial beta-oxidation

NARCIS (Netherlands)

Bennett, M. J.; Spotswood, S. D.; Ross, K. F.; Comfort, S.; Koonce, R.; Boriack, R. L.; IJlst, L.; Wanders, R. J.

1999-01-01

This report describes the clinical, biochemical, and pathological findings in three infants with hepatic short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase (SCHAD) deficiency, a recently recognized disorder of the mitochondrial oxidation of straight-chain fatty acids. Candidate subjects were

Lithiated short side chain perfluorinated sulfonic ionomeric membranes: Water content and conductivity

Science.gov (United States)

Navarrini, Walter; Scrosati, Bruno; Panero, Stefania; Ghielmi, Alessandro; Sanguineti, Aldo; Geniram, Giuliana

In view of possible applications as single-ion electrolyte for lithium batteries, some aspects of the lithium form of Hyflon Ion ionomer, a sulfonic short side chain (SSC) electrolyte, have been investigated. The synthesis of the ionomer and the successive membrane preparation is reported. An appropriate methodology for the direct salification of the ionomeric membrane from the SO 2F form to lithium salt, using lithium hydroxide in absence of organic solvent has been found. Utilizing these SSC lithium ionomer membranes and though a particular methodology for the dehydration of the lithium ion membrane in non-aqueous media, it has been possible to achieve an ionic conductivity of 10 -3 S cm -1 at room temperature [W. Navarrini, S. Panero, B. Scrosati, A. Sanguineti, European Patent 1,403,958 A1 (2003)]. Surprisingly it was observed that the membrane ionic conductivity depends on the dehydration methodologies adopted.

A hybrid non-ribosomal peptide/polyketide synthetase containing fatty-acyl ligase (FAAL synthesizes the β-amino fatty acid lipopeptides puwainaphycins in the Cyanobacterium Cylindrospermum alatosporum.

Directory of Open Access Journals (Sweden)

Jan Mareš

Full Text Available A putative operon encoding the biosynthetic pathway for the cytotoxic cyanobacterial lipopeptides puwainphycins was identified in Cylindrospermum alatosporum. Bioinformatics analysis enabled sequential prediction of puwainaphycin biosynthesis; this process is initiated by the activation of a fatty acid residue via fatty acyl-AMP ligase and continued by a multidomain non-ribosomal peptide synthetase/polyketide synthetase. High-resolution mass spectrometry and nuclear magnetic resonance spectroscopy measurements proved the production of puwainaphycin F/G congeners differing in FA chain length formed by either 3-amino-2-hydroxy-4-methyl dodecanoic acid (4-methyl-Ahdoa or 3-amino-2-hydroxy-4-methyl tetradecanoic acid (4-methyl-Ahtea. Because only one puwainaphycin operon was recovered in the genome, we suggest that the fatty acyl-AMP ligase and one of the amino acid adenylation domains (Asn/Gln show extended substrate specificity. Our results provide the first insight into the biosynthesis of frequently occurring β-amino fatty acid lipopeptides in cyanobacteria, which may facilitate analytical assessment and development of monitoring tools for cytotoxic cyanobacterial lipopeptides.

The effect of short-chain fatty acids on human monocyte-derived dendritic cells

DEFF Research Database (Denmark)

Nastasi, Claudia; Candela, Marco; Bonefeld, Charlotte Menné

2015-01-01

negligible effects, while both butyrate and propionate strongly modulated gene expression in both immature and mature human monocyte-derived DC. An Ingenuity pathway analysis based on the differentially expressed genes suggested that propionate and butyrate modulate leukocyte trafficking, as SCFA strongly......The gut microbiota is essential for human health and plays an important role in the pathogenesis of several diseases. Short-chain fatty acids (SCFA), such as acetate, butyrate and propionate, are end-products of microbial fermentation of macronutrients that distribute systemically via the blood....... The aim of this study was to investigate the transcriptional response of immature and LPS-matured human monocyte-derived DC to SCFA. Our data revealed distinct effects exerted by each individual SCFA on gene expression in human monocyte-derived DC, especially in the mature ones. Acetate only exerted...

40 CFR 721.10055 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts.

Science.gov (United States)

2010-07-01

...-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts. 721.10055 Section 721.10055 Protection of...-amino-N-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts. (a) Chemical substance and...-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts (PMN P-03-46; CAS No. 136504-87-5) is subject to...

Des-Acyl Ghrelin and Ghrelin O-Acyltransferase Regulate Hypothalamic-Pituitary-Adrenal Axis Activation and Anxiety in Response to Acute Stress

NARCIS (Netherlands)

Stark, R.; Santos, V.V.; Geenen, B.; Cabral, A.; Dinan, T.; Bayliss, J.A.; Lockie, S.H.; Reichenbach, A.; Lemus, M.B.; Perello, M.; Spencer, S.J.; Kozicz, L.T.; Andrews, Z.B.

2016-01-01

Ghrelin exists in two forms in circulation, acyl ghrelin and des-acyl ghrelin, both of which have distinct and fundamental roles in a variety of physiological functions. Despite this fact, a large proportion of papers simply measure and refer to plasma ghrelin without specifying the acylation

Synthesis and Bioactivity of Pyrazole Acyl Thiourea Derivatives

Directory of Open Access Journals (Sweden)

Jian Wu

2012-05-01

Full Text Available Sixteen novel pyrazole acyl thiourea derivatives 6 were synthesized from monomethylhydrazine (phenylhydrazine and ethyl acetoacetate. The key 5-chloro-3-methyl-1-substituted-1H-pyrazole-4-carbonyl chloride intermediates 4 were first generated in four steps through cyclization, formylation, oxidation and acylation. Thess were then reacted with ammonium thiocyanate in the presence of PEG-400 to afford 5-chloro-3-methyl-1-substituted-1H-pyrazole-4-carbonyl isothiocyanates 5. Subsequent reaction with fluorinated aromatic amines resulted in the formation of the title compounds. The synthesized compound were unequivocally characterized by IR, ¹H-NMR, ¹³C-NMR and elemental analysis and some of the synthesized compounds displayed good antifungal activities against Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica and anti-TMV activity in preliminary antifungal activity tests.

Novel short chain fatty acids restore chloride secretion in cystic fibrosis

International Nuclear Information System (INIS)

Nguyen, Toan D.; Kim, Ug-Sung; Perrine, Susan P.

2006-01-01

Phenylalanine deletion at position 508 of the cystic fibrosis transmembrane conductance regulator (ΔF508-CFTR), the most common mutation in cystic fibrosis (CF), causes a misfolded protein exhibiting partial chloride conductance and impaired trafficking to the plasma membrane. 4-Phenylbutyrate corrects defective ΔF508-CFTR trafficking in vitro, but is not clinically efficacious. From a panel of short chain fatty acid derivatives, we showed that 2,2-dimethyl-butyrate (ST20) and α-methylhydrocinnamic acid (ST7), exhibiting high oral bioavailability and sustained plasma levels, correct the ΔF508-CFTR defect. Pre-incubation (≥6 h) of CF IB3-1 airway cells with ≥1 mM ST7 or ST20 restored the ability of 100 μM forskolin to stimulate an 125 I - efflux. This efflux was fully inhibited by NPPB, DPC, or glibenclamide, suggesting mediation through CFTR. Partial inhibition by DIDS suggests possible contribution from an additional Cl - channel regulated by CFTR. Thus, ST7 and ST20 offer treatment potential for CF caused by the ΔF508 mutation

THE EFFECTS OF EXERCISE ON FOOD INTAKE AND HUNGER: RELATIONSHIP WITH ACYLATED GHRELIN AND LEPTIN

Directory of Open Access Journals (Sweden)

Serife Vatansever-Ozen

2011-06-01

Full Text Available This study investigated the effects of a long bout of aerobic exercise on hunger and energy intake and circulating levels of leptin and acylated ghrelin. Ten healthy male subjects undertook two, 4 h trials in a randomized crossover design. In the exercise trial subjects ran for 105 min at 50% of maximal oxygen uptake and the last 15 min at 70% of maximal oxygen uptake followed by a 120 min rest period. In the control trial, subjects rested for 4 h. Subjects consumed a buffet test meal at 180 min during each trial. Hunger ratings, acylated ghrelin, leptin, glucose and insulin concentrations were measured at 0, 1, 2, 3 and 4 h. No differences were found at baseline values for hunger, acylated ghrelin, leptin, insulin and glucose for both trials (p > 0.05. The estimated energy expenditure of the exercise trial was 1550 ± 136 kcal. Exercise did not change subsequent absolute energy intake, but produced a significant decrease (p < 0.05 in relative energy intake. A two-way ANOVA revealed a significant (p < 0. 05 interaction effect for hunger and acylated ghrelin. In conclusion, this exercise regimen had a positive effect on reducing appetite which is related to reduced acylated ghrelin responses over time. This finding lends support for a role of exercise in weight management

Majority of cellular fatty acid acylated proteins are localized to the cytoplasmic surface of the plasma membrane

International Nuclear Information System (INIS)

Wilcox, C.A.; Olson, E.N.

1987-01-01

The BC 2 Hl muscle cell line was previously reported to contain a broad array of fatty acid acylated proteins. Palmitate was shown to be attached to membrane proteins posttranslationally through thiol ester linkages, whereas myristate was attached cotranslationally, or within seconds thereafter, to soluble and membrane-bound proteins through amide linkages. The temporal and subcellular differences between palmitate and myristate acylation suggested that these two classes of acyl proteins might follow different intracellular pathways to distinct subcellular membrane systems or organelles. In this study, the authors examined the subcellular localization of the major fatty acylated proteins in BC 4 Hl cells. Palmitate-containing proteins were localized to the plasma membrane, but only a subset of myristate-containing proteins was localized to this membrane fraction. The majority of acyl proteins were nonglycosylated and resistant to digestion with extracellular proteases, suggesting that they were not exposed to the external surface of the plasma membrane. Many proteins were, however, digested during incubation of isolated membranes with proteases, which indicates that these proteins were, however, digested during incubation of isolated membranes with proteases, which indicates that these proteins face the cytoplasm. Two-dimensional gel electrophoresis of proteins labeled with [ 3 H]palmitate and [ 3 H]myristate revealed that individual proteins were modified by only one of the two fatty acids and did not undergo both N-linked myristylation and ester-linked palmitylation. Together, these results suggest that the majority of cellular acyl proteins are routed to the cytoplasmic surface of the plasma membrane, and they raise the possibility that fatty acid acylation may play a role in intracellular sorting of nontransmembranous, nonglycosylated membrane proteins

Two bifunctional enzymes from the marine protist Thraustochytrium roseum: biochemical characterization of wax ester synthase/acyl-CoA:diacylglycerol acyltransferase activity catalyzing wax ester and triacylglycerol synthesis.

Science.gov (United States)

Zhang, Nannan; Mao, Zejing; Luo, Ling; Wan, Xia; Huang, Fenghong; Gong, Yangmin

2017-01-01

Triacylglycerols (TAGs) and wax esters (WEs) are important neutral lipids which serve as energy reservoir in some plants and microorganisms. In recent years, these biologically produced neutral lipids have been regarded as potential alternative energy sources for biofuel production because of the increased interest on developing renewable and environmentally benign alternatives for fossil fuels. In bacteria, the final step in TAG and WE biosynthetic pathway is catalyzed by wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT). This bifunctional WS/DGAT enzyme is also a key enzyme in biotechnological production of liquid WE via engineering of plants and microorganisms. To date, knowledge about this class of biologically and biotechnologically important enzymes is mainly from biochemical characterization of WS/DGATs from Arabidopsis, jojoba and some bacteria that can synthesize both TAGs and WEs intracellularly, whereas little is known about WS/DGATs from eukaryotic microorganisms. Here, we report the identification and characterization of two bifunctional WS/DGAT enzymes (designated TrWSD4 and TrWSD5) from the marine protist Thraustochytrium roseum . Both TrWSD4 and TrWSD5 comprise a WS-like acyl-CoA acyltransferase domain and the recombinant proteins purified from Escherichia coli Rosetta (DE3) have substantial WS and lower DGAT activity. They exhibit WS activity towards various-chain-length saturated and polyunsaturated acyl-CoAs and fatty alcohols ranging from C 10 to C 18 . TrWSD4 displays WS activity with the lowest K m value of 0.14 μM and the highest k cat / K m value of 1.46 × 10 5  M -1  s -1 for lauroyl-CoA (C 12:0 ) in the presence of 100 μM hexadecanol, while TrWSD5 exhibits WS activity with the lowest K m value of 0.96 μM and the highest k cat / K m value of 9.83 × 10 4  M -1  s -1 for decanoyl-CoA (C 10:0 ) under the same reaction condition. Both WS/DGAT enzymes have the highest WS activity at 37 and 47�

Production of specific-structured lipids by enzymatic interesterification: elucidation of acyl migration by response surface design

DEFF Research Database (Denmark)

Xu, Xuebing; Skands, Anja; Høy, Carl-Erik

1998-01-01

Production of specific-structured lipids (SSL) by lipase-catalyzed interesterification has been attracting more and more attention recently. However, it was found that acyl migration occurs during the reaction and causes the production of by-products. In this paper, the elucidation of acyl...

Short-chain fatty acids induced autophagy serves as an adaptive strategy for retarding mitochondria-mediated apoptotic cell death

OpenAIRE

Tang, Y; Chen, Y; Jiang, H; Nie, D

2010-01-01

Short-chain fatty acids (SCFAs) are the major by-products of bacterial fermentation of undigested dietary fibers in the large intestine. SCFAs, mostly propionate and butyrate, inhibit proliferation and induce apoptosis in colon cancer cells, but clinical trials had mixed results regarding the anti-tumor activities of SCFAs. Herein we demonstrate that propionate and butyrate induced autophagy in human colon cancer cells to dampen apoptosis whereas inhibition of autophagy potentiated SCFA induc...

In silico approach to investigating the adsorption mechanisms of short chain perfluorinated sulfonic acids and perfluorooctane sulfonic acid on hydrated hematite surface.

Science.gov (United States)

Feng, Hongru; Lin, Yuan; Sun, Yuzhen; Cao, Huiming; Fu, Jianjie; Gao, Ke; Zhang, Aiqian

2017-05-01

Short chain perfluorinated sulfonic acids (PFSAs) that were introduced as alternatives for perfluorooctane sulfonic acid (PFOS) have been widely produced and used. However, few studies have investigated the environmental process of short chain PFSAs, and the related adsorption mechanisms still need to be uncovered. The water-oxide interface is one of the major environmental interfaces that plays an important role in affecting the adsorption behaviour and transport potential of the environmental pollutant. In this study, we performed molecular dynamics simulations and quantum chemistry calculations to investigate the adsorption mechanisms of five PFSAs and their adsorption on hydrated hematite surface as well. Different to the vertical configuration reported for PFOS on titanium oxide, all PFSAs share the same adsorption configuration as the long carbon chains parallel to the surface. The formation of hydrogen bonds between F and inter-surface H helps to stabilize the unique configuration. As a result, the sorption capacity increases with increasing C-F chain length. Moreover, both calculated adsorption energy and partial density of states (PDOS) analysis demonstrate a PFSAs adsorption mechanism in between physical and chemical adsorption because the hydrogen bonds formed by the overlap of F (p) orbital and H (s) orbital are weak intermolecular interactions while the physical adsorption are mainly ascribed to the electrostatic interactions. This massive calculation provides a new insight into the pollutant adsorption behaviour, and in particular, may help to evaluate the environmental influence of pollutants. Copyright © 2017. Published by Elsevier Ltd.

Asymmetric Chemoenzymatic Reductive Acylation of Ketones by a Combined Iron-Catalyzed Hydrogenation-Racemization and Enzymatic Resolution Cascade

KAUST Repository

El-Sepelgy, Osama; Brzozowska, Aleksandra; Rueping, Magnus

2017-01-01

. By merging the iron-catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones, as well as diketones, were reductively acylated. The corresponding products were isolated with high

Selective Acylation Enhances Membrane Charge Sensitivity of the Antimicrobial Peptide Mastoparan-X

DEFF Research Database (Denmark)

Etzerodt, Thomas Povl; Henriksen, Jonas Rosager; Rasmussen, Palle

2011-01-01

and positioning of the peptide in the membrane caused by either PA or OA acylation play a critical role in the fine-tuning of the effective charge of the peptide and thereby the fine-tuning of the peptide's selectivity between neutral and negatively charged lipid membranes. This finding is unique compared...... to previous reports where peptide acylation enhanced membrane affinity but also resulted in impaired selectivity. Our result may provide a method of enhancing selectivity of antimicrobial peptides toward bacterial membranes due to their high negative charge—a finding that should be investigated for other...

Effect of acute exposure to ergot alkaloids on short-chain fatty acid absorption and barrier function of isolated bovine ruminal epithelium

Science.gov (United States)

Ergot alkaloids present in endophyte-infected tall fescue are the causative agents for fescue toxicosis in cattle. Ergot alkaloids have been shown to cause a reduction in blood flow to the rumen epithelium as well as a decrease in short-chain fatty acid (SCFA) absorption from the washed rumen of ste...

SHORT COMMUNICATION Repellency property of long chain ...

African Journals Online (AJOL)

Repellency property of long chain aliphatic methyl ketones against Anopheles gambiae s.s ... tained from huge diversity of plant species are an important source of safe .... dry and then introduced with the hand covered by a glove in .... citronellal in repelling bees from basil (Oci- ... Journal of American Mosquito Control As-.

Novel endogenous N-acyl amides activate TRPV1-4 receptors, BV-2 microglia, and are regulated in brain in an acute model of inflammation

Science.gov (United States)

Raboune, Siham; Stuart, Jordyn M.; Leishman, Emma; Takacs, Sara M.; Rhodes, Brandon; Basnet, Arjun; Jameyfield, Evan; McHugh, Douglas; Widlanski, Theodore; Bradshaw, Heather B.

2014-01-01

A family of endogenous lipids, structurally analogous to the endogenous cannabinoid, N-arachidonoyl ethanolamine (Anandamide), and called N-acyl amides have emerged as a family of biologically active compounds at TRP receptors. N-acyl amides are constructed from an acyl group and an amine via an amide bond. This same structure can be modified by changing either the fatty acid or the amide to form potentially hundreds of lipids. More than 70 N-acyl amides have been identified in nature. We have ongoing studies aimed at isolating and characterizing additional members of the family of N-acyl amides in both central and peripheral tissues in mammalian systems. Here, using a unique in-house library of over 70 N-acyl amides we tested the following three hypotheses: (1) Additional N-acyl amides will have activity at TRPV1-4, (2) Acute peripheral injury will drive changes in CNS levels of N-acyl amides, and (3) N-acyl amides will regulate calcium in CNS-derived microglia. Through these studies, we have identified 20 novel N-acyl amides that collectively activate (stimulating or inhibiting) TRPV1-4. Using lipid extraction and HPLC coupled to tandem mass spectrometry we showed that levels of at least 10 of these N-acyl amides that activate TRPVs are regulated in brain after intraplantar carrageenan injection. We then screened the BV2 microglial cell line for activity with this N-acyl amide library and found overlap with TRPV receptor activity as well as additional activators of calcium mobilization from these lipids. Together these data provide new insight into the family of N-acyl amides and their roles as signaling molecules at ion channels, in microglia, and in the brain in the context of inflammation. PMID:25136293

Functional and structural characterization of a thermostable acetyl esterase from Thermotoga maritima

NARCIS (Netherlands)

Levisson, M.; Han, G.W.; Deller, M.C.; Hendriks, S.N.A.; Oost, van der J.; Kengen, S.W.M.

2012-01-01

TM0077 from Thermotoga maritima is a member of the carbohydrate esterase family 7 and is active on a variety of acetylated compounds, including cephalosporin C. TM0077 esterase activity is confined to short-chain acyl esters (C2-C3), and is optimal around 100°C and pH 7.5. The positional specificity

The first three years of screening for medium chain acyl-CoA dehydrogenase deficiency (MCADD by newborn screening ontario

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Fisher Lawrence

2010-11-01

Full Text Available Abstract Background Medium chain acyl-CoA dehydrogenase deficiency (MCADD is a disorder of mitochondrial fatty acid oxidation and is one of the most common inborn errors of metabolism. Identification of MCADD via newborn screening permits the introduction of interventions that can significantly reduce associated morbidity and mortality. This study reports on the first three years of newborn screening for MCADD in Ontario, Canada. Methods Newborn Screening Ontario began screening for MCADD in April 2006, by quantification of acylcarnitines (primarily octanoylcarnitine, C8 in dried blood spots using tandem mass spectrometry. Babies with positive screening results were referred to physicians at one of five regional Newborn Screening Treatment Centres, who were responsible for diagnostic evaluation and follow-up care. Results From April 2006 through March 2009, approximately 439 000 infants were screened for MCADD in Ontario. Seventy-four infants screened positive, with a median C8 level of 0.68 uM (range 0.33-30.41 uM. Thirty-one of the screen positive infants have been confirmed to have MCADD, while 36 have been confirmed to be unaffected. Screening C8 levels were higher among infants with MCADD (median 8.93 uM compared to those with false positive results (median 0.47 uM. Molecular testing was available for 29 confirmed cases of MCADD, 15 of whom were homozygous for the common c.985A > G mutation. Infants homozygous for the common mutation tended to have higher C8 levels (median 12.13 uM relative to compound heterozygotes for c.985A > G and a second detectable mutation (median 2.01 uM. Eight confirmed mutation carriers were identified among infants in the false positive group. The positive predictive value of a screen positive for MCADD was 46%. The estimated birth prevalence of MCADD in Ontario is approximately 1 in 14 000. Conclusions The birth prevalence of MCADD and positive predictive value of the screening test were similar to those

Structural and Functional Studies of Fatty Acyl Adenylate Ligases from E. coli and L. pneumophila

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.; Swaminathan, S.; Zhou, R.; Sauder, J. M.; Tonge, P. J.; Burley, S. K.

2011-02-18

Fatty acyl-AMP ligase (FAAL) is a new member of a family of adenylate-forming enzymes that were recently discovered in Mycobacterium tuberculosis. They are similar in sequence to fatty acyl-coenzyme A (CoA) ligases (FACLs). However, while FACLs perform a two-step catalytic reaction, AMP ligation followed by CoA ligation using ATP and CoA as cofactors, FAALs produce only the acyl adenylate and are unable to perform the second step. We report X-ray crystal structures of full-length FAAL from Escherichia coli (EcFAAL) and FAAL from Legionella pneumophila (LpFAAL) bound to acyl adenylate, determined at resolution limits of 3.0 and 1.85 {angstrom}, respectively. The structures share a larger N-terminal domain and a smaller C-terminal domain, which together resemble the previously determined structures of FAAL and FACL proteins. Our two structures occur in quite different conformations. EcFAAL adopts the adenylate-forming conformation typical of FACLs, whereas LpFAAL exhibits a unique intermediate conformation. Both EcFAAL and LpFAAL have insertion motifs that distinguish them from the FACLs. Structures of EcFAAL and LpFAAL reveal detailed interactions between this insertion motif and the interdomain hinge region and with the C-terminal domain. We suggest that the insertion motifs support sufficient interdomain motions to allow substrate binding and product release during acyl adenylate formation, but they preclude CoA binding, thereby preventing CoA ligation.

Acylation Reactions over Zeolites and Mesoporous Catalysts

Czech Academy of Sciences Publication Activity Database

Voláková, Martina; Vitvarová, Dana; Čejka, Jiří

2009-01-01

Roč. 2, č. 6 (2009), s. 486-499 ISSN 1864-5631 R&D Projects: GA ČR GA104/07/0383; GA ČR GD203/08/H032; GA MPO FT-TA5/005 Institutional research plan: CEZ:AV0Z40400503 Keywords : acylation * ketones * mesoporous materials * shape-selectivity * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.767, year: 2009

Evaluating the Environmental Fate of Short-Chain Chlorinated Paraffins (SCCPs) in the Nordic Environment Using a Dynamic Multimedia Model

OpenAIRE

Krogseth, Ingjerd Sunde; Breivik, Knut; Arnot, Jon A; Wania, Frank; Borgen, Anders; Schlabach, Martin

2013-01-01

Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SC...

Endotoxin Structures in the Psychrophiles Psychromonas marina and Psychrobacter cryohalolentis Contain Distinctive Acyl Features

Directory of Open Access Journals (Sweden)

Charles R. Sweet

2014-07-01

Full Text Available Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide, a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2- units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments.

Disruption of the Acyl-CoA binding protein gene delays hepatic adaptation to metabolic changes at weaning

DEFF Research Database (Denmark)

Neess, Ditte; Marcher, Ann-Britt; Bloksgaard, Maria

The acyl-CoA binding protein/diazepam binding inhibitor (ACBP/DBI) is an evolutionary conserved intracellular protein that binds C14-C22 acyl-CoA esters with very high affinity. ACBP is thought to act as an acyl-CoA transporter, and in vitro analyses have indicated that ACBP can transport acyl......-CoA esters between different enzymatic systems. However, little is known about the in vivo function in mammalian cells. We have generated mice with targeted disruption of ACBP (ACBP-/-). These mice are viable and fertile and develop normally. However, around weaning the ACBP-/- mice show decreased growth......) family, around the weaning period. As a result, the hepatic de novo cholesterogenesis is significantly decreased at weaning. The delayed induction of SREBP target genes around weaning is caused by a compromised processing and decreased expression of SREBP precursors leading to reduced binding of SREBP...

Relationships between acylated ghrelin with growth hormone, insulin resistance, lipid profile, and cardio respiratory function in lean and obese men

Directory of Open Access Journals (Sweden)

Hasan Matin Homaee

2011-01-01

Conclusions: Obese and lean inactive young men had different levels of acylated ghrelin, GH, insulin, insulin resistance index, cardiorespiratory function and body fat percent. Body fat percent, insulin, and GH levels appear to be best determinant factors of acylated ghrelin levels. Also, in both obese and lean young men, higher levels of cardiovascular function were associated with higher levels of acylated ghrelin.

Biodiesel production by esterification of oleic acid with short-chain alcohols under ultrasonic irradiation condition

Energy Technology Data Exchange (ETDEWEB)

Hanh, Hoang Duc; Okitsu, Kenji; Nishimura, Rokuro; Maeda, Yasuaki [Department of Applied Material Science, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531 (Japan); Dong, Nguyen The [Institute of Environmental Technology, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam)

2009-03-15

Production of fatty acid ethyl ester (FAEE) from oleic acid (FFA) with short-chain alcohols (ethanol, propanol, and butanol) under ultrasonic irradiation was investigated in this work. Batch esterification of oleic acid was carried out to study the effect of: test temperatures of 10-60 C, molar ratios of alcohol to oleic acid of 1:1-10:1, quantity of catalysts of 0.5-10% (wt of sulfuric acid/wt of oleic acid) and irradiation times of 10 h. The optimum condition for the esterification process was molar ratio of alcohol to oleic acid at 3:1 with 5 wt% of H{sub 2}SO{sub 4} at 60 C with an irradiation time of 2 h. (author)

Proteomic analysis of the response of Escherichia coli to short-chain fatty acids.

Science.gov (United States)

Rodríguez-Moyá, María; Gonzalez, Ramon

2015-06-03

Given their simple and easy-to-manipulate chemical structures, short-chain fatty acids (SCFAs) are valuable feedstocks for many industrial applications. While the microbial production of SCFAs by engineered Escherichia coli has been demonstrated recently, productivity and yields are limited by their antimicrobial properties. In this work, we performed a comparative proteomic analysis of E. coli under octanoic acid stress (15 mM) and identified the underlying mechanisms of SCFA toxicity. Out of a total of 33 spots differentially expressed at a p-value ≤ 0.05, nine differentially expressed proteins involved in transport and structural roles (OmpF, HPr, and FliC), oxidative stress (SodA, SodB, and TrxA), protein synthesis (PPiB and RpsA) and metabolic functions (HPr, PflB) were selected for further investigation. Our studies suggest that membrane damage and oxidative stress are the main routes of inhibition by SCFAs in E. coli. The outer membrane porin OmpF had the greatest impact on SCFA tolerance. Intracellular pH analysis on ompF mutants grown under octanoic acid stress indicated that this porin facilitates transport of SCFAs into the cell. The same response was observed under hexanoic acid stress, further supporting the role of OmpF in response to the presence of SCFAs. Furthermore, analysis of membrane protein expression revealed that other outer membrane porins are also involved in the response of E. coli to SCFAs. This work covers the first known proteomic analysis to assess the inhibitory effect of SCFAs in E. coli. SCFAs are molecules of great interest in the industry, but their microbial production is limited by their antimicrobial properties. This work allowed identification of differentially expressed proteins in response to SCFA stress and demonstrated the relevance of short- and medium-chain FA transport across the cell membrane via outer membrane porins, providing valuable insights on the toxicity mechanism of SCFAs in E. coli. These results could

Identification and quantification of intermediates of unsaturated fatty acid metabolism in plasma of patients with fatty acid oxidation disorders

NARCIS (Netherlands)

Onkenhout, W.; Venizelos, V.; van der Poel, P. F.; van den Heuvel, M. P.; Poorthuis, B. J.

1995-01-01

The free fatty acid and total fatty acid profiles in plasma of nine patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, two with very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency and two with mild-type multiple acyl-CoA dehydrogenase (MAD-m) deficiency, were analyzed by gas

Coulomb repulsion in short polypeptides.

Science.gov (United States)

Norouzy, Amir; Assaf, Khaleel I; Zhang, Shuai; Jacob, Maik H; Nau, Werner M

2015-01-08

Coulomb repulsion between like-charged side chains is presently viewed as a major force that impacts the biological activity of intrinsically disordered polypeptides (IDPs) by determining their spatial dimensions. We investigated short synthetic models of IDPs, purely composed of ionizable amino acid residues and therefore expected to display an extreme structural and dynamic response to pH variation. Two synergistic, custom-made, time-resolved fluorescence methods were applied in tandem to study the structure and dynamics of the acidic and basic hexapeptides Asp6, Glu6, Arg6, Lys6, and His6 between pH 1 and 12. (i) End-to-end distances were obtained from the short-distance Förster resonance energy transfer (sdFRET) from N-terminal 5-fluoro-l-tryptophan (FTrp) to C-terminal Dbo. (ii) End-to-end collision rates were obtained for the same peptides from the collision-induced fluorescence quenching (CIFQ) of Dbo by FTrp. Unexpectedly, the very high increase of charge density at elevated pH had no dynamical or conformational consequence in the anionic chains, neither in the absence nor in the presence of salt, in conflict with the common view and in partial conflict with accompanying molecular dynamics simulations. In contrast, the cationic peptides responded to ionization but with surprising patterns that mirrored the rich individual characteristics of each side chain type. The contrasting results had to be interpreted, by considering salt screening experiments, N-terminal acetylation, and simulations, in terms of an interplay of local dielectric constant and peptide-length dependent side chain charge-charge repulsion, side chain functional group solvation, N-terminal and side chain charge-charge repulsion, and side chain-side chain as well as side chain-backbone interactions. The common picture that emerged is that Coulomb repulsion between water-solvated side chains is efficiently quenched in short peptides as long as side chains are not in direct contact with each

Application of liquid chromatography-mass spectrometry to measure the concentrations and study the synthesis of short chain fatty acids following stable isotope infusions

NARCIS (Netherlands)

Meesters, R.J.W.; Eijk, H.M.H. van; Have, G.A.M. ten; Graaf, A.A. de; Venema, K.; Rossum, B.E.J. van; Deutz, N.E.P.

2007-01-01

A new method involving zinc sulphate deproteinization was developed to study short chain fatty acids (SCFA) production in the colon and subsequent occurrence of SCFA in blood. SCFA were baseline separated in a 30 min cycle using ion-exclusion chromatography and detected by mass spectrometry.

Impact of the long chain omega-acylceramides on the stratum corneum lipid nanostructure. Part 1: Thermotropic phase behaviour of CER[EOS] and CER[EOP] studied using X-ray powder diffraction and FT-Raman spectroscopy.

Science.gov (United States)

Kessner, Doreen; Brezesinski, Gerald; Funari, Sergio S; Dobner, Bodo; Neubert, Reinhard H H

2010-01-01

The stratum corneum (SC), the outermost layer of the mammalian skin, is the main skin barrier. Ceramides (CERs) as the major constituent of the SC lipid matrix are of particular interest. At the moment, 11 classes of CERs are identified, but the effect of each single ceramide species is still not known. Therefore in this article, the thermotropic behaviour of the long chain omega-acylceramides CER[EOS] and CER[EOP] was studied using X-ray powder diffraction and FT-Raman spectroscopy. It was found that the omega-acylceramides CER[EOS] and CER[EOP] do not show a pronounced polymorphism which is observed for shorter chain ceramides as a significant feature. The phase behaviour of both ceramides is strongly influenced by the extremely long acyl-chain residue. The latter has a much stronger influence compared with the structure of the polar head group, which is discussed as extremely important for the appearance of a rich polymorphism. Despite the strong influence of the long chain, the additional OH-group of the phyto-sphingosine type CER[EOP] influences the lamellar repeat distance and the chain packing. The less polar sphingosine type CER[EOS] is stronger influenced by the long acyl-chain residue. Hydration is necessary for the formation of an extended hydrogen-bonding network between the polar head groups leading to the appearance of a long-periodicity phase (LPP). In contrast, the more polar CER[EOP] forms the LPP with densely packed alkyl chains already in the dry state.

Gas-phase acylation of aminopropyl-silica gel in the synthesis of some chemically bonded silica materials for analytical applications

International Nuclear Information System (INIS)

Basiuk, Vladimir; Khil'chevskaya, E.G.

1991-01-01

Gas-phase acylation of aminopropyl-silica gel with aliphatic dicarboxylic (succinic, adipic and sebacic) and 4-aminobenzoic acids is proposed as a rapid and efficient one-step method for the synthesis of carboxyalkyl- and 4-aminophenylamidopropyl-silica gels, usually used as zwitterion exchangers for liquid chromatography and matrices for multi-step syntheses of silica-bound aromatic azo reagents for the sorption and chromatographic separation of metal ions. Acylation degrees of 59-90% are achieved after 0.5 h. IR spectra of the acylation products and near-UV-visible spectra for bonded aromatic azo compounds, based on 4-aminobenzamidopropyl-silica gel, are presented. Some positive and negative aspects of the gas-phase acylation are discussed. (author). 34 refs.; 2 figs.; 2 tabs

Acylated 2-(N-arylaminomethylene)benzo[b]thiophene-3(2H)-Ones: Molecular Switches with Varying Migrants and Substituents

International Nuclear Information System (INIS)

Dubonosov, A.D.; Rybalkin, V.P.; Tsukanov, A.V.; Minkin, V.I.; Popova, L.L.; Revinsky, Y.V.; Bren, V.A.; Minkin, V.I.

2009-01-01

Synthesis and properties of photo chromic acylated 2-(N-arylaminomethylene)benzo[b]thiophene-3(2H)-ones are described. Their structure largely depends on the nature of acyl migrant and in a less degree on N-aryl substituent.

Activation of Short and Long Chain Fatty Acid Sensing Machinery in the Ileum Lowers Glucose Production in Vivo.

Science.gov (United States)

Zadeh-Tahmasebi, Melika; Duca, Frank A; Rasmussen, Brittany A; Bauer, Paige V; Côté, Clémence D; Filippi, Beatrice M; Lam, Tony K T

2016-04-15

Evidence continues to emerge detailing the myriad of ways the gut microbiota influences host energy homeostasis. Among the potential mechanisms, short chain fatty acids (SCFAs), the byproducts of microbial fermentation of dietary fibers, exhibit correlative beneficial metabolic effects in humans and rodents, including improvements in glucose homeostasis. The underlying mechanisms, however, remain elusive. We here report that one of the main bacterially produced SCFAs, propionate, activates ileal mucosal free fatty acid receptor 2 to trigger a negative feedback pathway to lower hepatic glucose production in healthy rats in vivo We further demonstrate that an ileal glucagon-like peptide-1 receptor-dependent neuronal network is necessary for ileal propionate and long chain fatty acid sensing to regulate glucose homeostasis. These findings highlight the potential to manipulate fatty acid sensing machinery in the ileum to regulate glucose homeostasis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

N-Cinnamoylation of Antimalarial Classics: Effects of Using Acyl Groups Other than Cinnamoyl toward Dual-Stage Antimalarials.

Science.gov (United States)

Gomes, Ana; Machado, Marta; Lobo, Lis; Nogueira, Fátima; Prudêncio, Miguel; Teixeira, Cátia; Gomes, Paula

2015-08-01

In a follow-up study to our reports of N-cinnamoylated chloroquine and quinacrine analogues as promising dual-stage antimalarial leads with high in vitro potency against both blood-stage Plasmodium falciparum and liver-stage Plasmodium berghei, we decided to investigate the effect of replacing the cinnamoyl moiety with other acyl groups. Thus, a series of N-acylated analogues were synthesized, and their activities against blood- and liver-stage Plasmodium spp. were assessed along with their in vitro cytotoxicities. Although the new N-acylated analogues were found to be somewhat less active and more cytotoxic than their N-cinnamoylated counterparts, they equally displayed nanomolar activities in vitro against blood-stage drug-sensitive and drug-resistant P. falciparum, and significant in vitro liver-stage activity against P. berghei. Therefore, it is demonstrated that simple N-acylated surrogates of classical antimalarial drugs are promising dual-stage antimalarial leads. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superhydrophilic surfaces from short and medium chain solvo-surfactants

Directory of Open Access Journals (Sweden)

Valentin Romain

2013-01-01

Full Text Available Pure monoglycerides (GM-Cs and glycerol carbonate esters (GCE-Cs are two families of oleochemical molecules composed of a polar part, glycerol for GM-Cs, glycerol carbonate for GCE-Cs, and a fatty acid lipophilic part. From a chemical point of view, GM-Cs include two free oxygen atoms in the hydroxyl functions and one ester function between the fatty acid and the glycerol parts. GCE-Cs contain two blocked oxygen atoms in the cyclic carbonate backbone and three esters functions: two endocyclic in the five-membered cyclic carbonate function, one exocyclic between the fatty acid and glycerol carbonate parts. At the physico-chemical level, GMCs and GCE-Cs are multifunctional molecules with amphiphilic structures: a common hydrophobic chain to the both families and a polar head, glycerol for GMs and glycerol carbonate for GCE-Cs. Physicochemical properties depend on chain lengths, odd or even carbon numbers on the chain, and glyceryl or cyclocarbonic polar heads. The solvo-surfactant character of GM-Cs and overall GCE-Cs were discussed through the measurements of critical micellar concentration (CMC or critical aggregation concentration (CAC. These surface active glycerol esters/glycerol carbonate esters were classified following their hydrophilic/hydrophobic character correlated to their chain length (LogPoctanol/water = f(atom carbon number. Differential scanning calorimetry and optical polarized light microscopy allow us to highlight the selfassembling properties of the glycerol carbonate esters alone and in presence of water. We studied by thermal analysis the polymorphic behaviour of GCE-Cs, and the correlation between their melting points versus the chain lengths. Coupling the self-aggregation and crystallization properties, superhydrophilic surfaces were obtained by formulating GM-Cs and GCE-Cs. An efficient durable water-repellent coating of various metallic and polymeric surfaces was allowed. Such surfaces coated by self-assembled fatty acid

Short-chain alkanes synergise responses of moth pests to their sex pheromones.

Science.gov (United States)

Gurba, Alexandre; Guerin, Patrick M

2016-05-01

The use of sex pheromones for mating disruption of moth pests of crops is increasing worldwide. Efforts are under way to augment the efficiency and reliability of this control method by adding molecules derived from host plants to the sex attractants in dispensers. We show how attraction of the European grapevine moth, Lobesia botrana Den. & Schiff., and the codling moth, Cydia pomonella L., males to underdosed levels of their sex pheromones is increased by adding heptane or octane over a range of release rates. Pheromone-alkane mixtures enhance male recruitment by up to 30%, reaching levels induced by calling females, and shorten the flight time to the sex attractant by a factor of 2. The findings show the promise of using short-chain alkanes as pheromone synergists for mating disruption of insect pests of food crops. Alkane-pheromone combinations are expected to increase the competitiveness of dispensers with females, and to reduce the amount of pheromone needed for the control of these pests. © 2015 Society of Chemical Industry.

Extending our knowledge of fermentable, short-chain carbohydrates for managing gastrointestinal symptoms.

Science.gov (United States)

Barrett, Jacqueline S

2013-06-01

The Monash University low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet is now accepted as an effective strategy for managing symptoms of irritable bowel syndrome (IBS) in Australia, with interest expanding across the world. These poorly absorbed, short-chain carbohydrates have been shown to induce IBS symptoms of diarrhea, bloating, abdominal pain, and flatus due to their poor absorption, osmotic activity, and rapid fermentation. Four clinical trials have been published to date, all with significant symptomatic response to the low FODMAP diet. Up to 86% of patients with IBS have achieved relief of overall gastrointestinal symptoms and, more specifically, bloating, flatus, abdominal pain, and altered bowel habit from the approach. This review provides an overview of the low FODMAP diet and summarizes the research to date, emerging concepts, and limitations. FODMAPs are known to be beneficial to bowel health; the importance of this and how this should be considered in the clinical management of IBS is also discussed. A clinical management flowchart is provided to assist nutrition professionals in the use of this approach.

Imaging N-acyl homoserine lactone quorum sensing in vivo

DEFF Research Database (Denmark)

Christensen, Louise Dahl; van Gennip, Maria; Jakobsen, Tim Holm

2011-01-01

In order to study N-acyl homoserine lactone (AHL)-based quorum sensing in vivo, we present a protocol using an Escherichia coli strain equipped with a luxR-based monitor system, which in the presence of exogenous AHL molecules expresses a green fluorescent protein (GFP). Lungs from mice challenged...

Imaging N-acyl homoserine lactone quorum sensing in vivo

DEFF Research Database (Denmark)

Hultqvist, Louise Dahl; Alhede, Maria; Jakobsen, Tim Holm

2018-01-01

In order to study N-acyl homoserine lactone (AHL)-based quorum sensing in vivo, we present a protocol using an Escherichia coli strain equipped with a luxR-based monitor system, which in the presence of exogenous AHL molecules expresses a green fluorescent protein (GFP). Lungs from mice challenged...

Profiling acylated homoserine lactones in Yersinia ruckeri and influence of exogenous acyl homoserine lactones and known quorum-sensing inhibitors on protease production

DEFF Research Database (Denmark)

Kastbjerg, Vicky Gaedt; Nielsen, Kristian Fog; Dalsgaard, Inger

2007-01-01

produced at least eight different acylated homoserine lactones (AHLs) with N-(3-oxooctanoyl)-l-homoserine lactone (3-oxo-C8-HSL) being the dominant molecule. Also, some uncommon AHL, N-(3-oxoheptanoyl)-l-homoserine lactone (3-oxo-C7-HSL) and N-(3-oxononanoyl)-l-homoserine lactone (3-oxo-C9-HSL), were...

Asymmetric Chemoenzymatic Reductive Acylation of Ketones by a Combined Iron-Catalyzed Hydrogenation-Racemization and Enzymatic Resolution Cascade

KAUST Repository

El-Sepelgy, Osama

2017-02-28

A general and practical process for the conversion of prochiral ketones into the corresponding chiral acetates has been realized. An iron carbonyl complex is reported to catalyze the hydrogenation-dehydrogenation-hydrogenation of prochiral ketones. By merging the iron-catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones, as well as diketones, were reductively acylated. The corresponding products were isolated with high yields and enantioselectivities. The use of an iron catalyst together with molecular hydrogen as the hydrogen donor and readily available ethyl acetate as acyl donor make this cascade process highly interesting in terms of both economic value and environmental credentials.