- Profiling structural diversity and activity of 2-alkyl-4(1H)-quinoloneN-oxides ofPseudomonasandBurkholderia
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We synthesized all major saturated and unsaturated 2-alkyl-4(1H)-quinoloneN-oxides ofPseudomonasandBurkholderia, quantified their native production levels and characterized their antibiotic activities against competingStaphylococcus aureus. We demonstrate that quinolone core methylation and position of unsaturation in the alkyl-chain dictate antibiotic potency which supports the proposed mechanism of action.
- B?ttcher, Thomas,Dieterich, Cora Lisbeth,Prothiwa, Michaela,Szamosvári, Dávid
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supporting information
p. 6328 - 6331
(2020/06/21)
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- COMPOUND FOR USE AGAINST PATHOGENIC NEISSERIA AND HAEMOPHILUS SPECIES AND MORAXELLA CATARRHALIS
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The present invention relates to a compound, which can be used in the prevention and treatment of infections with pathogenic Neisseria species, in particular N. gonorrhoeae and N. meningitidis (the gonococcus and the meningococcus, respectively), and other pathogenic bacteria (e.g. Haemophilus species or Moraxella catarrhalis ), and which can be used for disinfecting a substrate from said bacteria. Moreover, the present invention relates to a corresponding pharmaceutical composition comprising said compound.
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- Quinolones modulate ghrelin receptor signaling: Potential for a novel small molecule scaffold in the treatment of cachexia
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Cachexia is a metabolic wasting disorder characterized by progressive weight loss, muscle atrophy, fatigue, weakness, and appetite loss. Cachexia is associated with almost all major chronic illnesses including cancer, heart failure, obstructive pulmonary disease, and kidney disease and significantly impedes treatment outcome and therapy tolerance, reducing physical function and increasing mortality. Current cachexia treatments are limited and new pharmacological strategies are needed. Agonists for the growth hormone secretagogue (GHS-R1a), or ghrelin receptor, prospectively regulate the central regulation of appetite and growth hormone secretion, and therefore have tremendous potential as cachexia therapeutics. Non-peptide GHS-R1a agonists are of particular interest, especially given the high gastrointestinal degradation of peptide-based structures, including that of the endogenous ligand, ghrelin, which has a half-life of only 30 min. However, few compounds have been reported in the literature as non-peptide GHS-R1a agonists. In this paper, we investigate the in vitro potential of quinolone compounds to modulate the GHS-R1a in both transfected human cells and mouse hypothalamic cells. These chemically synthesized compounds demonstrate a promising potential as GHS-R1a agonists, shown by an increased intracellular calcium influx. Further studies are now warranted to substantiate and exploit the potential of these novel quinolone-based compounds as orexigenic therapeutics in conditions of cachexia and other metabolic and eating disorders.
- Torres-Fuentes, Cristina,Pastor-Cavada, Elena,Cano, Rafael,Kandil, Dalia,Shanahan, Rachel,Juan, Rocio,Shaban, Hamdy,McGlacken, Gerard P.,Schellekens, Harri?t
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- An Unsaturated Quinolone N-Oxide of Pseudomonas aeruginosa Modulates Growth and Virulence of Staphylococcus aureus
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The pathogen Pseudomonas aeruginosa produces over 50 different quinolones, 16 of which belong to the class of 2-alkyl-4-quinolone N-oxides (AQNOs) with various chain lengths and degrees of saturation. We present the first synthesis of a previously proposed unsaturated compound that is confirmed to be present in culture extracts of P. aeruginosa, and its structure is shown to be trans-Δ1-2-(non-1-enyl)-4-quinolone N-oxide. This compound is the most active agent against S. aureus, including MRSA strains, by more than one order of magnitude whereas its cis isomer is inactive. At lower concentrations, the compound induces small-colony variants of S. aureus, reduces the virulence by inhibiting hemolysis, and inhibits nitrate reductase activity under anaerobic conditions. These studies suggest that this unsaturated AQNO is one of the major agents that are used by P. aeruginosa to modulate competing bacterial species.
- Szamosvári, Dávid,B?ttcher, Thomas
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supporting information
p. 7271 - 7275
(2017/06/13)
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- Preparation of the even-numbered 3-oxo fatty acid nicotinyl esters from C6:0 to C18:0
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Here, we report a systematic comparison of different methods for the transesterification of 3-oxo fatty acid alkyl esters to the corresponding nicotinyl esters. A simple method producing the target esters in high yields and purity has been developed. Nicotinyl esters are of interest for mass spectrometry analysis of fatty acids. Also, the hydrophilic head group of nicotinyl esters can be used as the basis for the preparation of liposome-building molecules.
- Sieben, Daniela,Santana, Alexander,Nowka, Paul,Weber, Sven,Funke, Kai,Hüttenhain, Stefan H.
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supporting information
p. 808 - 810
(2016/02/03)
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- Exploiting interkingdom interactions for development of small-molecule inhibitors of candida albicans biofilm formation
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A rapid decline in the development of new antimicrobial therapeutics has coincided with the emergence of new and more aggressive multidrug-resistant pathogens. Pathogens are protected from antibiotic activity by their ability to enter an aggregative biofilm state. Therefore, disrupting this process in pathogens is a key strategy for the development of next-generation antimicrobials. Here, we present a suite of compounds, based on the Pseudomonas aeruginosa 2-heptyl-4(1H)-quinolone (HHQ) core quinolone interkingdom signal structure, that exhibit noncytotoxic antibiofilm activity toward the fungal pathogen Candida albicans. In addition to providing new insights into what is a clinically important bacterium-fungus interaction, the capacity to modularize the functionality of the quinolone signals is an important advance in harnessing the therapeutic potential of signaling molecules in general. This provides a platform for the development of potent next-generation small-molecule therapeutics targeting clinically relevant fungal pathogens.
- Reen, F. Jerry,Phelan, John P.,Gallagher, Lorna,Woods, David F.,Shanahan, Rachel M.,Cano, Rafael,Muimhneacháin, Eoin ó,McGlacken, Gerard P.,O'Gara, Fergal
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p. 5894 - 5905
(2016/11/06)
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- A structure activity-relationship study of the bacterial signal molecule HHQ reveals swarming motility inhibition in Bacillus atrophaeus
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The sharp rise in antimicrobial resistance has been matched by a decline in the identification and clinical introduction of new classes of drugs to target microbial infections. Thus new approaches are being sought to counter the pending threat of a post-antibiotic era. In that context, the use of non-growth limiting small molecules, that target virulence behaviour in pathogens, has emerged as a solution with real clinical potential. We have previously shown that two signal molecules (HHQ and PQS) from the nosocomial pathogen Pseudomonas aeruginosa have modulatory activity towards other microorganisms. This current study involves the synthesis and evaluation of analogues of HHQ towards swarming and biofilm virulence behaviour in Bacillus atrophaeus, a soil bacterium and co-inhibitor with P. aeruginosa. Compounds with altered C6-C8 positions on the anthranilate-derived ring of HHQ, display a surprising degree of biological specificity, with certain candidates displaying complete motility inhibition. In contrast, anti-biofilm activity of the parent molecule was completely lost upon alteration at any position indicating a remarkable degree of specificity and delineation of phenotype.
- Reen, F. Jerry,Shanahan, Rachel,Cano, Rafael,O'Gara, Fergal,McGlacken, Gerard P.
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supporting information
p. 5537 - 5541
(2015/05/20)
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- Synthesis of β-ketoesters from renewable resources and Meldrum's acid
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β-Ketoesters are valuable building blocks for the synthesis of compounds with different biological activities. In this study, a series of fatty β-ketoesters were obtained from fatty acids and Meldrum's acid using N,N-dicyclohexylcarbodiimide and dimethylaminopyridine. In addition, we demonstrate for the first time the synthesis of new fatty β-ketoesters from oleic (cis-C18:1), elaidic (trans-C18:1), ricinoleic (cis-C18:1, 12-OH), linoleic (cis,cis-C18:2), and linolenic (cis,cis,cis-C18:3) acids in good yields.
- Brinkerhoff, Rafael C.,Tarazona, Hernan F.,De Oliveira, Patrick M.,Flores, Darlene C.,Montes D'Oca, Caroline Da R.,Russowsky, Dennis,Montes D'Oca, Marcelo G.
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p. 49556 - 49559
(2014/12/10)
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- Unusual acetylation-elimination in the formation of tetronate antibiotics
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The identity and reactivity of the intermediates in agglomerin biosynthesis were established and the respective roles of the acetyltransferase Agg4 and the eliminating enzyme Agg5 identified (see scheme). It is proposed that enzymes homologous to Agg4 and
- Kanchanabanca, Chompoonik,Tao, Weixin,Hong, Hui,Liu, Yajing,Hahn, Frank,Samborskyy, Markiyan,Deng, Zixin,Sun, Yuhui,Leadlay, Peter F.
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p. 5785 - 5788
(2013/07/11)
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- Immunomodulation and the quorum sensing molecule 3-oxo-C 12-homoserine lactone: The importance of chemical scaffolding for probe development
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As a guide for chemical probe design, focused analogue synthetic studies were undertaken upon the lactone ring of 3-oxo-C12-homoserine lactone. We have concluded that hydrolytic instability of the heterocyclic ring is pivotal for its ability to modulate immune signaling and probe preparation was aligned with these findings. The Royal Society of Chemistry 2013.
- Garner, Amanda L.,Yu, Jing,Struss, Anjali K.,Kaufmann, Gunnar F.,Kravchenko, Vladimir V.,Janda, Kim D.
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supporting information
p. 1515 - 1517
(2013/03/13)
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- Design, synthesis and biological evaluation of non-natural modulators of quorum sensing in Pseudomonas aeruginosa
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Many species of bacteria employ a mechanism of intercellular communication known as quorum sensing which is mediated by small diffusible signalling molecules termed autoinducers. The most common class of autoinducer used by Gram-negative bacteria are N-acylated-l-homoserine lactones (AHLs). Pseudomonas aeruginosa is a clinically important bacterium which is known to use AHL-mediated quorum sensing systems to regulate a variety of processes associated with virulence. Thus the selective disruption of AHL-based quorum sensing represents a strategy to attenuate the pathogenicity of this bacterium. Herein we describe the design, synthesis and biological evaluation of a collection of structurally novel AHL mimics. A number of new compounds capable of modulating the LasR-dependent quorum sensing system of P. aeruginosa were identified, which could have value as molecular tools to study and manipulate this signalling pathway. Worthy of particular note, this research has delivered novel potent quorum sensing antagonists, which strongly inhibit the production of virulence factors in a wild type strain of this pathogenic bacterium.
- Hodgkinson, James T.,Galloway, Warren R. J. D.,Wright, Megan,Mati, Ioulia K.,Nicholson, Rebecca L.,Welch, Martin,Spring, David R.
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p. 6032 - 6044
(2012/08/28)
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- Robust routes for the synthesis of N-acylated-l-homoserine lactone (AHL) quorum sensing molecules with high levels of enantiomeric purity
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The ready availability of native quorum sensing molecules and related structural analogues is of significant biological interest in the development of methods to manipulate bacterial quorum sensing systems in a useful fashion. In this Letter we report robust routes for the synthesis of a range of N-acylated-l-homoserine lactone (AHL) quorum sensing molecules. Crucially, we have analysed the enantiopurity of the final AHLs and in all cases, excellent levels were observed.
- Hodgkinson, James T.,Galloway, Warren R.J.D.,Casoli, Mariangela,Keane, Harriet,Su, Xianbin,Salmond, George P.C.,Welch, Martin,Spring, David R.
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p. 3291 - 3294
(2011/06/28)
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- Small molecule inhibitors of bacterial quorum sensing and biofilm formation
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Bacteria monitor their local population densities using small molecules (or autoinducers) in a process known as quorum sensing. Here, we report a new and efficient synthetic route to naturally occurring bacterial autoinducers [N-acyl L-homoserine lactones (AHLs)] that is readily amenable to the synthesis of analogues. This route has been applied in the first synthesis of a library of non-native AHLs. Evaluation of these compounds in bacterial reporter gene and biofilm assays has revealed a potent set of quorum sensing antagonists. These ligands will serve as valuable new tools to explore the role of quorum sensing in bacterial pathogenesis. Copyright
- Geske, Grant D.,Wezeman, Rachel J.,Siegel, Adam P.,Blackwell, Helen E.
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p. 12762 - 12763
(2007/10/03)
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- Synthesis and stability of small molecule probes for Pseudomonas aeruginosa quorum sensing modulation
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The human pathogen Pseudomonas aeruginosa uses N-butyryl-L-homoserine lactone (BHL) and N-(3-oxododecanyl)-L-homoserine lactone (OdDHL) as small molecule intercellular signals in a phenomenon known as quorum sensing (QS). QS modulators are effective at attenuating P. aeruginosa virulence; therefore, they are a potential new class of antibacterial agent. The lactone in BHL and OdDHL is hydrolysed under physiological conditions. The hydrolysis proceeds at a rate faster than racemisation of the α-chiral centre. Non-hydrolysable, non-racemic analogues (small molecule probes) were designed and synthesised, replacing the lactone with a ketone. OdDHL analogues were found to be relatively unstable to decomposition unless they were difluorinated between the β-keto amide. Stability studies on a non-hydrolysable, cyclohexanone analogue indicated that racemisation of the α-chiral centre was relatively slow. This analogue was assayed to show that the L-isomer is likely to be responsible for the QS autoinducing activity in P. aeruginosa and Serratia strain ATCC39006.
- Glansdorp, Freija G.,Thomas, Gemma L.,Lee, Jungjoon K.,Dutton, Jenny M.,Salmond, George P. C.,Welch, Martin,Spring, David R.
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p. 3329 - 3336
(2007/10/03)
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- Rhodium chemzymes: Michaelis-Menten kinetics in dirhodium(II) carboxylate-catalyzed carbenoid reactions
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Rhodium carboxylate-mediated reactions of diazoketones involving cyclopropanation, C-H insertion, and aromatic C-C double bond addition/electrocyclic ring opening obey saturation (Michaelis-Menten) kinetics. Axial ligands for rhodium, including aromatic hydrocarbons and Lewis bases such as nitriles, ethers, and ketones, inhibit these reactions by a mixed kinetic inhibition mechanism, meaning that they can bind both to the free catalyst and to the catalyst - substrate complex. Substrate inhibition can also be exhibited by diazocompounds bearing these groupings in addition to the diazo group. The analysis of inhibition shows that the active catalyst uses only one of its two coordination sites at a time for catalysis. Some ketones exhibit the interesting property that they selectively bind to the catalyst - substrate complex. The similarity of the kinetic constants from different types of reactions with similar diazoketones, regardless of the linking unit or the environment of the reacting alkene, suggests that the rate-determining step is the generation of the rhodium carbenoid. A very useful rhodium carboxylate catalyst for asymmetric synthesis, Rh2(DOSP)4, shows slightly slower kinetic parameters than the achiral catalysts, implying that enantiose-lectivity of this catalyst is based on slowing reactions from one of the enantiotopic faces of the reactant, rather than any type of ligand-accelerated catalysis. A series of rhodium catalysts derived from acids with pKas spanning 4 orders of magnitude give very similar kinetic constants.
- Pirrung, Michael C.,Liu, Hao,Morehead Jr., Andrew T.
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p. 1014 - 1023
(2007/10/03)
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- Reaction of methyl diazoacetate with aldehydes, amines, thiols, alcohols and acids over transition metal-exchanged clays
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Metal-exchanged clays (M = Rh and Cu) catalyze effectively the reaction of methyl diazoacetate with various aldehydes, affording the corresponding β-keto esters in high yields. They have also been effective in the decomposition of methyl diazoacetate to form metallocarbenes which, in turn, successfully insert into X-H (X = N, O, S, CO2) bonds of a variety of amines, aldehydes, thiols and acids, thereby producing the corresponding esters. The Royal Society of Chemistry 1999.
- Phukan, Prodeep,Mohan, Jakkam Madan,Sudalai, Arumugam
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p. 3685 - 3689
(2007/10/03)
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- Application of the Tethered Biginelli reaction for enantioselective synthesis of batzelladine alkaloids. Absolute configuration of the tricyclic guanidine portion of batzelladine B
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Tethered Biginelli condensation of enantioenriched hexahydropyrrolopyrimidines 8 with β-ketoesters provides efficient asymmetric access to tricyclic guanidines 9 having a syn relationship of the angular C2a and C8a hydrogens. This reaction was employed to realize the first practical enantioselective access to this fragment of batzelladine alkaloids B (2) and E (5). The efficiency of this strategy is illustrated in the synthesis of the dextrorotatory enantiomer of batzelladine B methanolysis product 10 in 10 steps and 25% overall yield from 2-nonanone and methyl acetoacetate. The asymmetric synthesis of 1.0 establishes that the absolute configuration of the tricyclic portion of batzelladine B (2) is 25aR,28S,30R. The 4-methyl-7-alkyl-1,2,2a,3,4,5,6,7,8,8a-decahydro-5,6,8b- triazaacenaphthalene-3-carboxylic acid subunit, e.g., 29, of batzelladine alkaloids A (1), D (4), F (6), and G was also prepared for the first time by catalytic hydrogenation of tricyclic guanidines 26 having the 2a,8a-anti stereochemistry.
- Franklin, Alison S.,Ly, Sylvie K.,Mackin, Gilbert H.,Overman, Larry E.,Shaka
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p. 1512 - 1519
(2007/10/03)
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- New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives
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A series of long-chain fatty acids and the corresponding 2-hydroxy, 2-oxo, 3-hydroxy acid glucosamides were evaluated as immunomodulating compounds. In a preliminary screening, 2-[(2-ethoxycarbonyloxy)tetradecanoyl-amino]-2-deoxy-D-glucose (2b) and 2-(3-hydroxydodecanoyl-amino)-2-deoxy-D-glucose (5a) resulted to be the most effective in enhancing the glucosamine activity. The findings of in vitro-ex vivo tests (unidirectional mixed lymphocyte culture reaction and primary antibody production) and in vivo tests (delayed type hypersensitivity, protection against bacterial or fungal infection and against Sarcoma 180 or Lewis lung carcinoma transplants) were very encouraging and allowed to assume for the two substances a protective activity, presumably through the ability of activating phagocytic and NK cells.
- Valcavi,Albertoni,Brandt,Corsi,Farina,Foresta,Pascucci,Ramacci
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p. 1190 - 1195
(2007/10/02)
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- The Preparation of Optically Pure 3-Hydroxyalkanoic Acid. The Enantioface-differentiating Hydrogenation of the C=O Double Bond with Modified Raney Nickel. XXXVII
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The enantioface-differentiating hydrogenation of methyl 3-oxoalkanoate (CH3(CH2)nCOCH2COOCH3, n=0, 6, 8, 10, 12) over the (R,R)-tartaric acid-NaBr-modified Raney nickel catalyst ((R,R)-TA-NaBr-MRNi) gave methyl (R)-3-hydroxyalkanoate (CH3(CH2)nCH(OH)CH2COOCH3, n=0, 6, 8, 10, 12) in an average optical yield of 85percent.After the methyl ester had been converted to dicyclohexylammonium salt of 3-hydroxyalkanoic acid, the salt was recrystallized three times from acetonitrile and then treated with acid to give optically pure (R)-3-hydroxyalkanoic acid (CH3(CH2)nCH(OH)CH2COOH, n=0, 6, 8, 10, 12) in a reasonable yield.From the hydrogenation product with (S,S)-TA-NaBr-MRNi, optically pure (S)-3-hydroxyalkanoic acid was obtained by the same process as above.
- Nakahata, Masaaki,Imaida, Motomasa,Ozaki, Hiroshi,Harada, Tadao,Tai, Akira
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p. 2186 - 2189
(2007/10/02)
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