Academic literature on the topic 'Phospholipase A1'

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Journal articles on the topic "Phospholipase A1"

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Badiani, K., and G. Arthur. "Evidence for receptor and G-protein regulation of a phosphatidylethanolamine-hydrolysing phospholipase A1 in guinea-pig heart microsomes: stimulation of phospholipase A1 activity by DL-isoprenaline and guanine nucleotides." Biochemical Journal 312, no. 3 (1995): 805–9. http://dx.doi.org/10.1042/bj3120805.

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While evidence has been presented for the receptor-mediated activation of phospholipases A2, C and D, the activation of phospholipase A1 subsequent to receptor activation has not been established. Phospholipase A1-catalysed hydrolysis of 1-palmitoyl-2-linoleoyl-glycerophosphoethanolamine (GPE) by guinea-pig heart microsomes was stimulated 40-60% by isoprenaline. This isoprenaline-mediated increase in activity was blocked by propranolol and butoxamine, a specific beta 2-adrenergic antagonist, but not by atenolol, a specific beta 1-adrenergic antagonist. Neither clonidine nor phenylephrine, alpha 1- and alpha 2-adrenergic agonists respectively, had a stimulatory effect on the hydrolysis of the PE substrate. Guanosine 5′(-)[gamma-thio]triphosphate (GTP[S]) and guanosine 5′(-)[beta, gamma-imido]triphosphate, but not guanosine 5′(-)[beta-thio]diphosphate (GDP[S]) or adenosine 5′(-)[gamma-thio]triphosphate, stimulated the hydrolysis of 1-palmitoyl-2-linoleoyl-GPE by phospholipase A1. GDP[S] inhibited the isoprenaline-mediated stimulation of phospholipase A1 activity. Phospholipase A1 hydrolysis of 1-palmitoyl-2-linoleoyl-GPE was not dependent on cations; however, the stimulatory effects of isoprenaline and GTP[S] on the hydrolytic activity were abolished by cation chelators. The above data suggest that phospholipase A1 activity in guinea-pig heart microsomes is activated by the binding of isoprenaline to beta 2-adrenergic receptors. Furthermore the stimulation of phospholipase A1 activity by the agonist may be mediated via activation of G-proteins.
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Badiani, K., X. Lu та G. Arthur. "Evidence for the regulation of guinea-pig heart microsomal phosphatidylcholine-hydrolysing phospholipase A1 by guanosine 5′-[γ-thio]triphosphate". Biochemical Journal 288, № 3 (1992): 965–68. http://dx.doi.org/10.1042/bj2880965.

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We have recently characterized lysophospholipase A2 activities in guinea-pig heart microsomes and postulated that these enzymes act sequentially with phospholipases A1 to release fatty acids selectively from phosphatidylcholine (PC) and phosphatidylethanolamine, thus providing an alternative route to the phospholipase A2 mode of release. In a further investigation of the postulated pathway, we have characterized the PC-hydrolysing phospholipase A1 in guinea-pig heart microsomes. Our results show that the enzyme may have a preference for substrates with C16:0 over C18:0 at the sn-1 position. In addition, although the enzyme cleaves the sn-1 fatty acid, the rate of hydrolysis of PC substrates with C16:0 at the sn-1 position was influenced by the nature of the fatty acid at the sn-2 position. The order of decreasing preference was C18:2 > C20:4 = C18:1 > C16:0. The hydrolyses of the molecular species were differentially affected by heating at 60 degrees C. An investigation into the effect of nucleotides on the activity of the enzyme showed that guanosine 5′-[gamma-thio]triphosphate (GTP[S]) inhibited the hydrolysis of PC by phospholipase A1 activity, whereas GTP, guanosine 5′-[beta-thio]diphosphate (GDP[S]), GDP, ATP and adenosine 5′-[gamma-thio]triphosphate (ATP[S]) did not affect the activity. The inhibitory effect of GTP[S] on phospholipase A1 activity was blocked by preincubation with GDP[S]. A differential effect of GTP[S] on the hydrolysis of different molecular species was also observed. Taken together, the results of this study suggest the presence of more than one phospholipase A1 in the microsomes with different substrate specificities, which act sequentially with lysophospholipase A2 to release linoleic or arachidonic acid selectively from PC under resting conditions. Upon stimulation and activation of the G-protein, the release of fatty acids would be inhibited.
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Reisfeld, Nurit, Dov Lichtenberg, Arie Dagan, and Saul Yedgar. "Apolipoprotein B exhibits phospholipase A1 and phospholipase A2 activities." FEBS Letters 315, no. 3 (1993): 267–70. http://dx.doi.org/10.1016/0014-5793(93)81176-z.

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Tani, Katsuko, Takeshi Kogure, and Hiroki Inoue. "The intracellular phospholipase A1 protein family." BioMolecular Concepts 3, no. 5 (2012): 471–78. http://dx.doi.org/10.1515/bmc-2012-0014.

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AbstractPhospholipase A1 is an enzyme that hydrolyzes phospholipids, producing 2-acyl-lysophospholipids and fatty acids. The intracellular phospholipase A1 (iPLA1) protein family is a relatively recently discovered lipid-metabolizing enzyme family. Lower eukaryotes, such as yeasts and nematodes, and plants have only one iPLA1 protein, whereas mammals have three iPLA1 family proteins (PA-PLA1/DDHD1/iPLA1α, p125/Sec23IP/iPLA1β and KIAA0725p/DDHD2/iPLA1γ). Mammalian iPLA1 proteins are localized in different cellular compartments, and two of them, p125 and KIAA0725p, have been implicated in membrane trafficking events. Recent gene targeting studies on several organisms showed that iPLA1 family proteins are involved in various physiological functions, including plant shoot gravitropism, epithelial stem cell differentiation and spermiogenesis. In this review, we describe the features of iPLA1 family proteins and recent progress regarding our understanding of their physiological functions.
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Inoue, Asuka, and Junken Aoki. "Phospholipase A1: structure, distribution and function." Future Lipidology 1, no. 6 (2006): 687–700. http://dx.doi.org/10.2217/17460875.1.6.687.

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Merino, Susana, Alicia Aguilar, Maria Mercedes Nogueras, Miguel Regue, Simon Swift, and Juan M. Tomás. "Cloning, Sequencing, and Role in Virulence of Two Phospholipases (A1 and C) from Mesophilic Aeromonas sp. Serogroup O:34." Infection and Immunity 67, no. 8 (1999): 4008–13. http://dx.doi.org/10.1128/iai.67.8.4008-4013.1999.

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ABSTRACT Two different representative recombinant clones encodingAeromonas hydrophila lipases were found upon screening on tributyrin (phospholipase A1) and egg yolk agar (lecithinase-phospholipase C) plates of a cosmid-based genomic library of Aeromonas hydrophila AH-3 (serogroup O34) introduced into Escherichia coli DH5α. Subcloning, nucleotide sequencing, and in vitro-coupled transcription-translation experiments showed that the phospholipase A1 (pla) and C (plc) genes code for an 83-kDa putative lipoprotein and a 65-kDa protein, respectively. Defined insertion mutants ofA. hydrophila AH-3 defective in either pla orplc genes were defective in phospholipase A1 and C activities, respectively. Lecithinase (phospholipase C) was shown to be cytotoxic but nonhemolytic or poorly hemolytic. A. hydrophila AH-3 plc mutants showed a more than 10-fold increase in their 50% lethal dose on fish and mice, and complementation of the plc single gene on these mutants abolished this effect, suggesting that Plc protein is a virulence factor in the mesophilic Aeromonas sp. serogroup O:34 infection process.
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KUNZE, Hans, Ernst BOHN, and Bernd-Michael LOFFLER. "Inhibitors of liver lysosomal acid phospholipase A1." European Journal of Biochemistry 177, no. 3 (1988): 591–95. http://dx.doi.org/10.1111/j.1432-1033.1988.tb14411.x.

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Manjula, Sarode, Anju Jose, Soundar Divakar, and Rangaswamy Subramanian. "Degumming rice bran oil using phospholipase-A1." European Journal of Lipid Science and Technology 113, no. 5 (2011): 658–64. http://dx.doi.org/10.1002/ejlt.201000376.

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Kim, M. K., J. K. Kim, and J. S. Rhee. "Isolation of a phospholipase A1-producing microorganism." Journal of Industrial Microbiology 16, no. 3 (1996): 171–74. http://dx.doi.org/10.1007/bf01570000.

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YOSHIDA, TADASHI, SHOZO NAKAMOTO, RYUZI SAKAZAKI, et al. "Thielocins A1.ALPHA. and A1.BETA., novel phospholipase A2 inhibitors from ascomycetes." Journal of Antibiotics 44, no. 12 (1991): 1467–70. http://dx.doi.org/10.7164/antibiotics.44.1467.

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Dissertations / Theses on the topic "Phospholipase A1"

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Kreuzeder, Julia. "Reinigung und Charakterisierung einer lysosomalen Phospholipase A1 aus Makrophagen." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15861.

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Makrophagen sind professionelle phagozytische Zellen, welche körpereigene gealterte oder toten Zellen und in den Körper eingedrungene Krankheitserreger aufnehmen. Die phagozytierten Partikel werden von lysosomalen Hydrolasen abgebaut und daraus hervorgehende Antigene an Zellen des spezifischen Immunsystems präsentiert. Aufgabe der lysosomalen Phospholipase A1 (PLA1) ist der Abbau von Phospholipiden. Sie spielt damit nicht nur eine elementare Rolle bei dem Abbau von Phospholipidmembranen nach Phago- und Autophagozytose, sondern kann auch an der Generation von Lipidantigenen beteiligt sein. Die vorliegende Arbeit bietet zum ersten Mal Hinweise auf die Sequenz der lysosomalen PLA1. Mittels proteinbiochemischer Reinigung und nachfolgender massenspektrometrischer Sequenzanalyse wurden zwei Proteinkandidaten identifiziert, welche der lysosomalen PLA1-Aktivität zugrunde liegen können. Des Weiteren werden ausführliche Untersuchungen zu den Katalyseeigenschaften des Enzyms an Liposomen präsentiert. Die Lipidzusammensetzung der Membran beeinflusst maßgeblich die Aktivität der lysosomalen PLA1. So haben in die Membran integrierte anionische Phospholipide eine stark enzymaktivierende Wirkung. Eine Erhöhung der Ionenstärke oder des pH-Wertes vermindern die Bindungsfähigkeit der lysosomalen PLA1 an die Membran und damit deren Aktivität. Dies lässt vermuten, dass elektrostatische Wechselwirkungen eine Rolle bei der Membranbindung spielen. Das Enzym besitzt pIs<br>Macrophages are professional phagocytes which engulf and degrade senescent and dead cells as well as pathogens. Phagocytosed particles are subsequently degraded by lysosomal enzymes. The lysosomal phospholipase A1 (PLA1) degrades phospholipids, the major components of biological membranes and, hence, plays a mandatory role in decomposition of phagocytosed and autophagocytosed membranes. Furthermore the enzyme might play a role in the processing of lipid antigens for immune presentation. Nevertheless, the gene encoding this important enzyme activity is as yet unknown. Here, we used proteinbiochemical methods to isolate the lysosomal PLA1 activity from RAW B cells and identified resulting sequences by tandem mass spectrometry. This analysis revealed for the first time two putative protein candidates responsible for lysosomal PLA1 activity. Using native enzyme fractions and liposome-embedded substrate, we show that PLA1 activity depends on the presence of anionic phospholipids, low pH and low ionic strength. Lysosomal PLA1 only attaches to membranes with anionic but not zwitterionic charges. High ionic strength impairs binding demonstrating that electrostatic attraction is responsible for membrane partitioning. Upon binding the enzyme remains on membranes for numerous catalytic cycles. The enzyme’s pIs at
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Perez-Riverol, Amilcar. "Recombinant phospholipase A1 from Polybia paulista wasp venom for molecular diagnosis of allergy /." Rio Claro, 2017. http://hdl.handle.net/11449/151777.

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Orientador: Márcia Regina Brochetto Braga<br>Coorientador: Mário Sergio Palma<br>Banca: Henrique Ferreira<br>Banca: Ricardo de Lima Zollner<br>Banca: Rogilene Aparecida Prado<br>Resumo: A fosfolipase A1 é um dos principais alérgenos identificados no veneno do Polybia paulista (Hymenoptera: Vespidae), uma vespa social de elevada importância clínica no sudeste do Brasil. A produção recombinante deste alérgeno contribuirá com o desenvolvimento do diagnóstico molecular de alergia. Neste trabalho é descrita a produção recombinante da fosfolipase A1 de P. paulista (rPoly p 1) no sistema celular Escherichia coli. Elevados níveis da rPoly p 1 na forma insolúvel foram obtidos após expressão na bactéria. A otimização das condições de solubilização permitiu incrementar os níveis de recuperação do alérgeno recombinante. A rPoly p 1 foi purificada (99%) até homogeneidade mediante cromatografia de afinidade em coluna de Ni2+, mostrando valores de rendimento finais de 1.5 g/L de meio de cultura. A forma nativa do alérgeno (nPoly p 1) foi purificada mediante cromatografia de troca catiônica. A rPoly p 1 foi reconhecida pela IgE específica de soros de pacientes sensibilizados ao veneno de P. paulista. O uso da rPoly p 1 permite diferenciar a ocorrência de real dupla sensibilização ao veneno de vespa e formiga ou vespa e abelha da incidência de reatividade cruzada. Soros de pacientes com IgE específica ao veneno de abelha e formiga não reagiram com a rPoly p 1, enquanto que soros de camundongos sensibilizados com rPoly p 1 apresentaram reatividade cruzada exclusivamente com fosfolipases A1 (PLA1) de vespas Neotropicais ou de climas temperados. O alinhamento múltiplo do modelo... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Phospholipase A1 (PLA1) is one of the major allergens identified in the venom Polybia paulista (Hymenoptera: Vespidae), a clinically relevant social wasp from Brazil Southeast. The recombinant production of this allergen could result in the development of molecular diagnosis of allergy thus improving the outcomes of venom immunotherapy (IT). Here, we describe the heterologous production of the PLA1 from P. paulista venom in Escherichia coli. High levels of the insoluble recombinant allergen (rPoly p 1) were obtained after expression in the prokaryotic system. The downstream optimization of the solubilization process resulted in high levels of protein recovery. The rPoly p 1 was purified to homogeneity (99%) using an immobilized Ni2+ metal affinity chromatography while a single-step cation-exchange chromatography allowed the purification of native Poly p 1 (nPoly p 1) from the venom glands. Immunoblotting analyses showed the IgE-mediated recognition of the rPoly p 1 by sera from patients sensitized to P. paulista venom. The rPoly p 1 could allow the differentiation of true double sensitization to wasp/bee and wasp/ant venoms from cross-reactivity. The sera from patients with monosensitization to honey bee or fire ant venoms do not cross-reacted with the recombinant allergen. Meanwhile, the sera from rPoly p 1-sensitized mice cross-reacted with venoms of other clinically relevant wasps from Neotropical and temperate regions. The alignment of the 3-D model from rPoly p 1 with the PLA1s from some of these wasps suggested the presence of homologues epitopes as the molecular basis for the cross-reactivity. The presence of cross-reactive carbohydrates determinants (CCDs) in the venom of several Brazilian wasps, which is a major issue for understanding the incidence of cross-reactivity during diagnosis, was also analyzed. Overall, the results described .. (Complete abstract click electronic access below)<br>Doutor
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Gassama-Diagne, Ama. "Les phospholipases digestives du cobaye : purification et caractérisation d'une nouvelle phospholipase B intestinale complémentaire de la phospholipase A1 pancréatique ; intérêt des deux enzymes dans l'étude des étherphospholipides et des lipocortines." Toulouse 3, 1989. http://www.theses.fr/1989TOU30210.

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Une premiere partie bibliographique rappelle quelques generalites sur la digestion des phospholipides, les donnees concernant les phospholipases impliquees dans ce phenomene et les autres hydrolases localisees dans la bordure en brosse de l'intestin. La deuxieme partie concerne les resultats experimentaux de l'etude de l'absorption de derives diacyl- et etherphospholipides par perfusion intestinale en circuit ferme chez le cobaye. Ces donnees nous ont permis de mettre en evidence dans la bordure en brosse une phospholipase a#2 que nous avons ensuite purifiee. Cet enzyme, qui a ete mieux caracterise, est en fait une phospholipase a#2 de poids moleculaire eleve, ayant egalement une activite lysophospholipasique (phospholipase b) et lipasique, toutes deux non dependantes du calcium. Dans une troisieme partie, la lipase pancreatique a forte activite phospholipasique a#1, deja purifiee dans le laboratoire, a ete utilisee pour mener une etude comparative de la composition tissulaire des etherphospholipides chez le cobaye, le rat et l'homme. L'independance vis-a-vis du calcium de cette lipase et celle de la phospholipase b intestinale nous ont permis d'utiliser ces enzymes pour mieux definir le role du calcium dans l'inhibition des phospholipases par les lipocortines
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El, Alaoui Meddy. "Développement de tests enzymatiques applicables au criblage des activités et/ou inhibiteurs de (phospho)lipases." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10179/document.

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La caractérisation de l'activité enzymatique des (phospho)lipases requiert des tests enzymatiques spécifiques, continus, utilisant des substrats lipidiques et adaptés au criblage à haut débit des activités et/ou des inhibiteurs de (phospho)lipases. Afin de développer de tels tests, la synthèse de glycérophosphatidylcholine (PC) estérifiée en position sn-1 et/ou sn-2 par l'acide alpha-éléostéarique (acide 9Z, 11E, 13E, octadécatriénoïque) a été effectuée. La triple insaturation conjuguée présente au sein de cet acide gras constitue un chromophore intrinsèque qui confère une forte absorption dans le domaine de l'ultra-violet à cet acide gras et aux lipides le contenant. Les PC contenant l'acide alpha-éléostéarique ont été adsorbées par « coating » au fond des puits d'une microplaque de titration. L'hydrolyse du substrat lipidique par une phospholipase A1 (PLA1) ou phospholipase A2 (PLA2), injectée dans le milieu réactionnel, est suivie en continu par l'augmentation de l'absorbance à 272 nm, due à la transition de l'acide alpha-éléostéarique de la phase adsorbée à la phase aqueuse. Des PC hétérogènes ont été synthétisées à partir de rac-glycidol pour effectuer un marquage sélectif de la PC par l'acide alpha-éléostéarique sur la position sn-1 (EOPC) ou sn-2 (OEPC). Pour empêcher la migration de la chaîne acyle, un lien éther non hydrolysable par les PLA1 ou PLA2 a été introduit sur l'autre position sn de la PC avec une chaîne alkyl (C18). Ces PC chimiquement définies ont permis d'élaborer une méthode de dosage en continu de l'activité enzymatique et discriminant les activités PLA1 ou PLA2, ce qui représente un caractère innovant par rapport à toutes les méthodes existantes<br>The characterization of the catalytic activity of (phospho)lipases requires specific assays, that are continuous, sensitive, use lipidic substrates and could be applied to high throughput screening. In order to perform these tests, several tailor-made alpha-eleostearic (9Z, 11E, 13E-octadecatrienoic acid) containing glycerophosphatidylcholines (PC) have been synthetized with the alpha-eleostearic acid at the position sn-1 and/or sn-2. The conjugated triene present in this fatty acid constitutes an intrinsic chromophore and, consequently, confers strong UV absorption properties of the fatty acid and the lipids harboring it. PC substrates were coated onto a microplate well and the phospholipase A1 (PLA1) or phospholipase A2 (PLA2) activity was measured continuously by the increase in absorbance, at 272 nm, due to the transition of alpha-eleostearic acid from the adsorbed to the soluble state. Moreover, two structured analogues of PC labeled at the sn-1 (EOPC) or sn-2 (OEPC) position with the alpha-eleostearic acid have been synthetized from rac-glycidol. A non-absorbing and non-hydrolysable by PLA1 and PLA2 O-ether alkyl(C18) was introduced at the other sn position to prevent intramolecular acyl chain migration during the synthesis and the lipolysis. These structured PC were coated onto a microplate and used in a continuous assay, to discriminate, with excellent accuracy, between PLA1 or PLA2 activities. The development of a sensitive enzymatic method using coated substrates analogues to natural lipid is a relevant improvement from current assays for measuring continuously (phosphor)lipases activities and/or their inhibitors due to the alpha-eleostearic acid UV spectroscopic properties
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Noiriel, Alexandre Benveniste Pierre Marc. "Étude d'une famille de gènes d'Arabidopsis thaliana homologues de la lécithine cholestérol acyltransférase humaine Caractérisation d'une nouvelle phospholipase A1 et étude d'une stérol acyltransférase /." Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/1061/01/NOIRIEL_Alexandre_2004.pdf.

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Noiriel, Alexandre. "Etude d'une famille de gènes d'Arabidopsis thaliana homologues de la lécithine cholestérol acyltransférase humaine : Caractérisation d'une nouvelle phospholipase A1 et étude d'une stérol acyltransférase." Université Louis Pasteur (Strasbourg) (1971-2008), 2004. https://publication-theses.unistra.fr/public/theses_doctorat/2004/NOIRIEL_Alexandre_2004.pdf.

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La cellule végétale régule sa teneur en stérols membranaires en estérifiant l'excès de stérols par des acides gras. L'enzyme qui catalyse cette réaction d'estérification, une stérol acyltransférase, n'était pas caractérisée chez les végétaux. Quatre gènes d'Arabidopsis thaliana présentent des homologies significatives avec HsLCAT, le gène de la lécithine cholestérol acyltransférase humaine, la protéine qui estérifie le cholestérol dans le plasma. Ces quatre gènes AtLCAT1, AtLCAT2, AtLCAT3 et AtLCAT4 ont été exprimés dans la levure et/ou dans les plantes. Deux d'entre eux ont été caractérisés. AtLCAT3 code une phospholipase A1, une enzyme hydrolysant spécifiquement les acides gras en position sn1 des phospholipides. La transformation de la levure par ce gène conduit à un doublement de la quantité de triglycérides, une augmentation des acides gras totaux de 40%, et à une forte perturbation du métabolisme lipidique. AtLCAT2 code une stérol acyltransférase. La surexpression de la protéine par transgenèse dans A. Thaliana ne modifie pas la teneur en esters de stérols dans les plantes entières, mais l'augmente dans des cals dérivant de ces plantes. Deux lignées mutantes comportant une insertion d'un T-DNA dans le gène AtLCAT2 ont été analysées. Leur quantité d'esters de stérols est réduite de 75% environ par rapport aux lignées témoins. L'acide mévalonique, précurseur des stérols et stimulateur de leur biosynthèse, a des effets toxiques sur ces lignées mutantes<br>The plant cell regulates the sterol content of its membranes through esterification by fatty acids of the sterol in excess. The enzyme catalysing the esterification reaction, a sterol acyltransferase, was not characterized in plants. Four Arabidopsis thaliana genes show significant homologies with HsLCAT, the human gene encoding lecithin cholesterol acyltransferase, which esterifies cholesterol in the plasma. These four genes AtLCAT1, AtLCAT2, AtLCAT3 and AtLCAT4 were expressed in yeast and/or plants. Two of them were characterized. AtLCAT3 encodes a phospholipase A1, an enzyme which specifically removes the fatty acid in position sn1 of phospholipids. Yeast transformation by this gene produces a doubling of its triacylglycerol content, an increase of the total fatty acid content by a factor 1. 4 and strong changes in the lipid metabolism. AtLCAT2 encodes a sterol acyltransferase. The protein overexpression by A. Thaliana transformation does not change the steryl ester content of whole plants but increases it in calli derived from these plants. Two mutant lines with a T-DNA insertion in the AtLCAT2 gene were analysed. Their sterol content is reduced by 75% in comparison to the control lines. Mevalonic acid, a sterol precursor which stimulates their biosynthesis, has toxic effects on mutant lines
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Bueno, Natalia Fernanda. "Caracterização de dois pares efetor/inibidor associados ao sistema de secreção tipo IV de Xanthomonas citri." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-24082018-094918/.

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O sistema de secreção tipo IV (T4SS) da família de bactérias Xanthomonadaceae transfere efetores (X-Tfes) com a capacidade de matar outras bactérias, conferindo uma vantagem em comunidades bacterianas mistas para colonizar diferentes nichos como o solo ou as superfícies das plantas. Os X-Tfes possuem diferentes domínios putativos com atividades hidrolíticas contra componentes do envelope celular bacteriano do tipo: glicohidrolases, transglicosilases, amidases e lipases. Os X-Tfes por sua atividade biológica inata podem ocasionar dano intracelular para a bactéria que os produz. Para se proteger contra estas atividades, também são produzidas lipoproteínas com função inibitoria (X-Tfis) localizadas no periplasma. Os genes que codificam os X-Tfes e os X-Tfis estão organizados em operons, o que permite gerar os pares efetor/inibidor simultaneamente. Entre os potenciais X-Tfes do fitopatógeno Xanthomonas citri estão Xac1918 e Xac0574. Xac1918 é uma proteína com um domínio da superfamília da lisozima e um domínio conhecido como RTX (Repeats in Toxin) de ligação ao cálcio, enquanto Xac0574 tem um domínio da superfamília da lipase 3. Os seus possíveis inibidores, Xac1917 e Xac0573 respectivamente, apresentam um peptídeo sinal no N-terminal contendo o lipobox representativo das lipoproteínas. As proteínas Xac0574 e Xac0573 são monômeros em solução que formam um complexo estável 1:1, favorecido termodinamicamente (&#916;G&#176;= -12 Kcal/mol) com uma constante de dissociação de 2,45 nM, garantindo que a bactéria fique protegida contra os efeitos nocivos de Xac0574 quando é produzida intracelularmente. Xac0574 é uma fosfolipase A1, sem atividade lisofosfolipase, com a capacidade de hidrolisar os três fosfolipídios majoritários que compõem a membrana celular bacteriana, fosfatidilglicerol (PG), cardiolipina e fosfatidiletanolamina (PE), mostrando uma aparente preferência pelo último. A atividade enzimática de Xac0574 explica a forte inibição do crescimento celular em E. coli após da sua indução heteróloga, já que gera uma diminuição de quase 10 vezes da população celular comparada com a cultura não induzida com a mesma construção. Poroutro lado, Xac0573 inibe efetivamente a atividade enzimática de Xac0574 ao formar o complexo, além de não ter atividade fosfolipase nem lisofosfolipase. Foram produzidos cristais da Xac1918 e Xac0573 que difrataram com uma resolução de 3,0 e 2,5 Å, respectivamente. Porém, só foi gerado um modelo de Xac0573. Xac0573 está composta por duas folhas &#946; antiparalelas com uma topologia característica de &#946; sanduíche Com uma pequena hélice e duas voltas. Um alinhamento de homólogos de Xac0573 identificou nas extremidades da proteína as regiões conservadas, constituindo duas possíveis interfaces de interação que podem ser as responsáveis por bloquear o acesso dos fosfolipídios ao sítio catalítico ou impedir os rearranjos estruturais de Xac0574 que são necessários para a sua atividade enzimática. Adicionalmente, a topologia da Xac0573 é semelhante do domínio C2, conhecido em eucariotos como domínio de ligação ao lipídio e ao cálcio, e está envolvido em processos de sinalização de segundos mensageiros lipídicos, proteínas de trafego de membranas e mecanismos de fusão de membranas. Nossos resultados apontam para uma nova função biológica do domínio C2 como um inibidor enzimático intracelular em bactérias.<br>The type IV secretion system (T4SS) of the bacteria family Xanthomonadaceae transfers effectors (X-Tfes) with that can kill other bacterial cells, conferring an advantage to the bacterial community during colonization of different niches in the soil or on the plant surface. The X-Tfes possess different putative domains with hydrolytic activity against components of the bacterial cellular envelope, including glycohydrolase, transglycolase, amidase and lipase domain. The innate biological activity of X-Tfes can cause intracellular damage. Therefore, the bacteria that produce them also produce lipoproteins with inhibitor function (X-Tfis) located in the periplasm for their protection. The genes that code for X-Tfes and X-Tfis are organized in operons that allow for their simultaneous expression. Among the X-Tfes of the phytopathogen Xanthomonas citri are Xac1918 and Xac0574. Xac1918 is carries a lysozyme superfamily domain, as well as a domain known as RTX (Repeats in Toxic) predict to bind calcium, while, Xac0574 has a domain belonging to the lipase 3 superfamily. Their possible inhibitors, Xac1917 e Xac0573 respectively, carry an N-terminal signal peptide containing a lipobox found in bacterial lipoproteins. The Xac0574 and Xac0573 proteins are both monomers in solution, They can form a stable 1:1 complex, that is thermodynamically favored (&#916;G&#176;= -12 Kcal/mol) with a dissociation constant of 2,45 nM. This affinity ensure that the bacterium is protected against the harmful effects of Xac0574 when it is produced intracellularly. We show that Xac0574 is a phospholipase A1, without lisophospholipase activity, and is able to hydrolyze the three most common phospholipids found in the membranes of Gram negative bacteria, namely phosphatidylglycerol (PG), cardiolipin and phosphatidylethanolamine (PE), presenting an apparent preference for PE. The enzymatic activity of Xac0574 explains the strong inhibition of growth of E. coli cells after its heterologous induction: a nearly 10-fold decrease in the cell population is observed when compared to the non-induced culture with the same construct. On the other hand, Xac0573 effectively inhibits the enzymatic activity of Xac0574. Furthermore, Xac0573 does not possess when forming the complex, besides not having phospholipase nor lysophospholipase activity.Crystals of Xac1918 and Xac0573 were produced which diffracted with to resolution of 3.0 and 2.5 Å, respectively. However, we were able to resolve the structure of only Xac0573. Xac0573 is composed of two anti-parallel sheet that form a &#946;-sandwich with three small helices. An alignment to Xac0573 homologs identified conserved regions at the ends of the protein that constitute two possible interfaces of interaction that may be responsible for blocking the access of the phospholipids to the catalytic site or impede the structural rearrangements of Xac0574 that are necessary for its enzymatic activity. Additionally, the topology of Xac0573 is similar to that to C2 domains, known in eukaryotes to bind lipids and calcium and to be involved in signaling processes mediated by lipid second messengers, membrane trafficking and membrane fusion mechanisms. Our results point to a new biological function of the C2 domain as an intracellular enzyme inhibitor in bacteria.
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Golly, Francis. "Metabolisme des phospholipides dans les neurones de poulet en culture primaire : modifications induites par la cdp-choline." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13149.

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Lors de lesions nerveuses par retrait de co::(2), l'etude du metabolisme des lipides a montre qu'un traitement a la cdp-choline ne modifie pas la distribution et la synthese des phospholipides et des acides gras mais provoque par contre une diminution de la liberation d'acides gras. La cdp-choline diminue l'activite phospholiposique a1 au niveau des membranes et protege donc celles-ci de la degradation
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Dippe, Martin [Verfasser], Renate [Akademischer Betreuer] Ulbrich-Hofmann, Ingo [Akademischer Betreuer] Heilmann, and Uwe T. [Akademischer Betreuer] Bornscheuer. "Transformation von Phospholipiden durch Phospholipasen A1 und Phospholipasen D : [kumulative Dissertation] / Martin Dippe. Betreuer: Renate Ulbrich-Hofmann ; Ingo Heilmann ; Uwe T. Bornscheuer." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2011. http://d-nb.info/1028857616/34.

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Collet, Xavier. "Interactions cellulaires des HDL modulations par les enzymes lipolytiques /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612931t.

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Book chapters on the topic "Phospholipase A1"

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Schomburg, Dietmar, and Margit Salzmann. "Phospholipase A1." In Enzyme Handbook 3. Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-76463-9_28.

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Kim, Hae Jin, and Stephen Beungtae Ryu. "sPLA2 and PLA1: Secretory Phospholipase A2 and Phospholipase A1 in Plants." In Signaling and Communication in Plants. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-42011-5_6.

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Tani, Katsuko, Takashi Baba, and Hiroki Inoue. "The Structures and Functions of Intracellular Phospholipase A1 Family Proteins." In Phospholipases in Health and Disease. Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0464-8_5.

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Inoue, Keizo, Hiroyuki Arai, and Junken Aoki. "Phospholipase A1 Structures, Physiological and Patho-physiological Roles in Mammals." In Lipases and Phospholipases in Drug Development. Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527601910.ch2.

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Nalbone, Gilles, Karl Y. Hostetler, Jeannie Leonardi, and Huguette Lafont. "Partial Characterization of the Cytosolic Phospholipase A1 of Rat Heart." In Enzymes of Lipid Metabolism II. Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5212-9_22.

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Tavernier, Eric, and Alain Pugin. "Phospholipase Activities Associated with the Tonoplast from Acer Pseudoplatanus Cells: Identification of a Phospholipase A1 Activity." In Plant Lipid Metabolism. Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8394-7_87.

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Diagne, Ama, Josette Fauvel, Salvador Mitjavila, Hugues Chap, and Louis Douste-Blazy. "Properties of Pancreatic Phospholipases A1 and Intestinal Phospholipase A2 from Guinea Pig: Their Complementary Role in the Intestinal Absorption of Phospholipids." In Enzymes of Lipid Metabolism II. Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5212-9_21.

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Waite, Moseley. "Cellular Phospholipases A1 and Lysophospholipases of Mammals." In The Phospholipases. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5353-9_6.

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Fredholm, Bertil B., Pär Gerwins, Jean W. Assender, and Eva Irenius. "Regulation of Phospholipases C and D, Calcium, and Protein Kinase C by Adenosine A1 Receptors." In Adenosine and Adenine Nucleotides: From Molecular Biology to Integrative Physiology. Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-2011-5_13.

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Haas, Eric, and David W. Stanley. "Phospholipase A1." In xPharm: The Comprehensive Pharmacology Reference. Elsevier, 2007. http://dx.doi.org/10.1016/b978-008055232-3.63621-9.

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Conference papers on the topic "Phospholipase A1"

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Iida, Yuuki, Eiji Sunami, Soichiro Ishihara, et al. "Abstract 31: Phosphatidylserine-specific phospholipase A1 (PSPLA1) expression in colorectal cancer correlates with tumor invasion and hematogenous metastasis." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-31.

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