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https://www.readbyqxmd.com/read/28535043/identification-and-quantification-of-acylated-homoserine-lactones-in-shewanella-baltica-the-specific-spoilage-organism-of-pseudosciaena-crocea-by-ultra-high-performance-liquid-chromatography-coupled-to-triple-quadrupole-mass-spectrometry
#1
Yanbo Wang, Xiaoxiao Zhang, Chong Wang, Linglin Fu, Yanyao Yi, Yan Zhang
Bacteria communicate with one another using chemical signal molecules called autoinducers, and the most prevalent autoinducers used by Gram-negative bacteria are N-acylated homoserine lactones (AHLs). However, AHLs are hardly detected in Shewanella baltica, the specific spoilage organism of Pseudosciaena crocea. In this study, we applied ultra-high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) to determine AHLs. This method enabled the quantification of up to 11 AHLs within 5...
May 23, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28530397/synthesis-of-1-4-oxazepane-2-5-diones-via-cyclization-of-rotationally-restricted-amino-acid-precursors-and-structural-reassignment-of-serratin
#2
Ewout Ruysbergh, Kristof Van Hecke, Christian Victor Stevens, Norbert De Kimpe, Sven Mangelinckx
Several natural products containing a 1,4-oxazepane-2,5-dione-core are known. One example is serratin, isolated from Serratia marcescens. Due to the presence of a carboxylic amide, which has a preference for a trans-conformation, and the presence of a labile lactone in this core, many synthetic methodologies commonly used for the cyclization towards medium-sized heterocycles cannot be applied. As N-acyl amino acids without a third substituent at nitrogen failed to undergo ring-closure, several N-protecting groups were evaluated...
May 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28530166/quorum-sensing-and-rsam-regulons-of-the-rice-pathogen-pseudomonas-fuscovaginae
#3
Gordana Uzelac, Hitendra Kumar Patel, Giulia Devescovi, Danilo Licastro, Vittorio Venturi
Pseudomonas fuscovaginae (Pfv) is an emerging plant pathogen causing sheath brown rot in rice, as well as diseases in other gramineae food crops including maize, sorghum and wheat. Pfv possesses two conserved N-acyl homoserine lactone (AHL) quorum sensing (QS) systems called PfvI/R and PfsI/R, which are repressed by RsaL and RsaM, respectively. The two systems are not hierarchically organized and are involved in plant virulence. In this study the AHL QS PfsI/R, PfvI/R and RsaM regulons were determined by transcriptomic analysis...
May 22, 2017: Microbiology
https://www.readbyqxmd.com/read/28526351/docosahexaenoyl-serotonin-emerges-as-most-potent-inhibitor-of-il-17-and-ccl-20-released-by-blood-mononuclear-cells-from-a-series-of-n-acyl-serotonins-identified-in-human-intestinal-tissue
#4
Ya Wang, Michiel G J Balvers, Henk F J Hendriks, Tessa Wilpshaar, Tjarda van Heek, Renger F Witkamp, Jocelijn Meijerink
Fatty acid amides (FAAs), conjugates of fatty acids with ethanolamine, mono-amine neurotransmitters or amino acids are a class of molecules that display diverse functional roles in different cells and tissues. Recently we reported that one of the serotonin-fatty acid conjugates, docosahexaenoyl serotonin (DHA-5-HT), previously found in gut tissue of mouse and pig, attenuates the IL-23-IL-17 signaling axis in LPS-stimulated mice macrophages. However, its presence and effects in humans remained to be elucidated...
May 16, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28525716/diastereoselective-and-catalytic-%C3%AE-alkylation-of-chiral-n-acyl-thiazolidinethiones-with-stable-carbocationic-salts
#5
Stuart C D Kennington, Mònica Ferré, Juan M Romo, Pedro Romea, Fèlix Urpí, Mercè Font-Bardia
Direct nickel-catalyzed alkylation of chiral (N)-acyl-4-isopropyl-1,3-thiazolidine-2- thiones using a commercially available nickel(II) complex, (Me3P)2NiCl2, has been developed for tropylium and trityl tetrafluoroborate salts. The reaction provides a single diastereomer of the corresponding adducts in good to high yields, which, in turn, can be easily converted into a wide array of enantiomerically pure compounds that are difficult to obtain by other asymmetric procedures.
May 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28510438/complex-effects-of-24-1-sphingolipids-in-membranes-containing-dioleoyl-phosphatidylcholine-and-cholesterol
#6
Aritz B Garcia-Arribas, Emilio J Gonzalez-Ramirez, Jesús Sot, Itziar Areso, Alicia Alonso, Felix M Goni
The effects of C24:1 sphingolipids have been tested in phospholipid bilayers containing cholesterol. Confocal microscopy, differential scanning calorimetry, and atomic force microscopy imaging and force curves have been used. More precisely, the effects of C24:1 ceramide (nervonoyl ceramide, nCer) were evaluated and compared to those of C16:0 ceramide (palmitoyl ceramide, pCer) in bilayers composed basically of dioleoyl phosphatidylcholine, sphingomyelin (either C24:1, nSM or C16:0, pSM) and cholesterol. Combination of equimolecular amounts of C24:1 and C16:0 sphingolipids were also studied under the same conditions...
May 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28493495/silver-catalyzed-three-component-1-1-aminoacylation-of-homopropargylamines-dual-additions-between-terminal-alkynes-and-isocyanides
#7
Shuo Tong, Cyril Piemontesi, Qian Wang, Mei-Xiang Wang, Jieping Zhu
Reaction of secondary homopropargylamines, isocyanides and water in the presence of a catalytic amount of silver acetate followed by silica gel chromatography purification afforded substituted proline amides in good to excellent yields. Primary homopropargylamines underwent cyclizative Ugi-Joullié three-component reaction with isocyanides and carboxylic acids to afford functionalized N-acyl proline amides. High diastereoselectivity was observed in the synthesis of 4-alkoxy and 4,5-disubstituted proline derivatives...
May 11, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28487993/acinetobacter%C3%A2-baumannii-quorum-sensing-signalling-molecule-induces-the-expression-of-drug-resistance-genes
#8
Yi Dou, Fei Song, Feng Guo, Zengding Zhou, Cailian Zhu, Jun Xiang, Jingning Huan
Quorum-sensing signalling molecules such as N‑acyl homoserine lactones (AHLs) enable certain Gram‑negative bacteria to respond to environmental changes through behaviours, such as biofilm formation and flagellar movement. The present study aimed to identify Acinetobacter baumannii AHLs and assess their influence on antibiotic resistance. A clinical isolate of A. baumannii strain S (AbS) was collected from the wound of a burn patient and high‑performance liquid chromatography and tandem quadrupole or quadrupole time‑of‑flight high‑resolution mass spectrometry was used to identify AbS AHLs...
June 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28485149/trapping-of-transient-zwitterionic-intermediates-by-n-acylpyridinium-salts-a-palladium-catalyzed-diastereoselective-three-component-reaction
#9
Dan Zhang, Zhenghui Kang, Wenhao Hu
We developed a palladium-catalyzed diastereoselective three-component reaction of N-aryl diazoamides, pyridine, and chloroformate, which proceeded through trapping of transient zwitterionic intermediates by in situ formed N-acylpyridinium salts in a regioselective 1,4-addition fashion. This reaction can rapidly provide a library of biologically relevant 4-(2-oxoindolin-3-yl)-1,4-dihydropyridine derivatives in high yields (up to 98%) with moderate to excellent diastereoselectivities (up to >95:5 dr) under mild reaction conditions...
May 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28474570/targeting-pparalpha-in-alzheimer-s-disease
#10
Barbara D Orio, Anna Fracassi, Maria Paola Cerù, Sandra Moreno
Alzheimer's disease (AD) is the result of a combination of genetic and environmental risk factors and the molecular mechanisms underlying cognitive decline are yet to be fully elucidated. The so-called "amyloid cascade hypothesis" has long been the prevailing paradigm for causation of disease, and today being revisited in relation to other pathogenic pathways, such as oxidative stress, neuroinflammation and lipid and glucose dysmetabolism. The peroxisome proliferator-activated receptors (PPARs) are expressed in the CNS and regulate many physiological processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle...
May 4, 2017: Current Alzheimer Research
https://www.readbyqxmd.com/read/28465425/plasma-membrane-association-by-n-acylation-governs-pkg-function-in-toxoplasma-gondii
#11
Kevin M Brown, Shaojun Long, L David Sibley
Cyclic GMP (cGMP)-dependent protein kinase (protein kinase G [PKG]) is essential for microneme secretion, motility, invasion, and egress in apicomplexan parasites, However, the separate roles of two isoforms of the kinase that are expressed by some apicomplexans remain uncertain. Despite having identical regulatory and catalytic domains, PKG(I) is plasma membrane associated whereas PKG(II) is cytosolic in Toxoplasma gondii To determine whether these isoforms are functionally distinct or redundant, we developed an auxin-inducible degron (AID) tagging system for conditional protein depletion in T...
May 2, 2017: MBio
https://www.readbyqxmd.com/read/28463102/high-intracellular-c-di-gmp-levels-antagonize-quorum-sensing-and-virulence-gene-expression-in-burkholderia-cenocepacia-h111
#12
Nadine Schmid, Angela Suppiger, Elisabeth Steiner, Gabriella Pessi, Volkhard Kaever, Mustafa Fazli, Tim Tolker-Nielsen, Urs Jenal, Leo Eberl
The opportunistic human pathogen Burkholderia cenocepacia H111 uses two chemically distinct signal molecules for controlling gene expression in a cell density-dependent manner: N-acyl-homoserine lactones (AHLs) and cis-2-dodecenoic acid (BDSF). Binding of BDSF to its cognate receptor RpfR lowers the intracellular c-di-GMP level, which in turn leads to differential expression of target genes. In this study we analysed the transcriptional profile of B. cenocepacia H111 upon artificially altering the cellular c-di-GMP level...
May 3, 2017: Microbiology
https://www.readbyqxmd.com/read/28462048/pitfalls-associated-with-evaluating-enzymatic-quorum-quenching-activity-the-case-of-moml-and-its-effect-on-pseudomonas-aeruginosa-and-acinetobacter-baumannii-biofilms
#13
Yunhui Zhang, Gilles Brackman, Tom Coenye
BACKGROUND: The enzymatic degradation of quorums sensing (QS) molecules (called quorum quenching, QQ) has been considered as a promising anti-virulence therapy to treat biofilm-related infections and combat antibiotic resistance. The recently-discovered QQ enzyme MomL has been reported to efficiently degrade different N-acyl homoserine lactones (AHLs) of various Gram-negative pathogens. Here we investigated the effect of MomL on biofilms formed by two important nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii...
2017: PeerJ
https://www.readbyqxmd.com/read/28453915/documenting-and-harnessing-the-biological-potential-of-molecules-in-distributed-drug-discovery-d3-virtual-catalogs
#14
Milata M Abraham, Ryan E Denton, Richard W Harper, William L Scott, Martin J O'Donnell, Jacob D Durrant
Virtual molecular catalogs have limited utility if member compounds are (1) difficult to synthesize or (2) unlikely to have biological activity. The Distributed Drug Discovery (D3) program addresses the synthesis challenge by providing scientists with a free virtual D3 catalog of 73,024 easy-to-synthesize N-acyl unnatural α-amino acids, their methyl esters, and primary amides. The remaining challenge is to document and exploit the bioactivity potential of these compounds. In the current work, a search process is described that retrospectively identifies all virtual D3 compounds classified as bioactive hits in PubChem-cataloged experimental assays...
April 28, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28446863/peptides-as-quorum-sensing-molecules-measurement-techniques-and-obtained-levels-in-vitro-and-in-vivo
#15
REVIEW
Frederick Verbeke, Severine De Craemer, Nathan Debunne, Yorick Janssens, Evelien Wynendaele, Christophe Van de Wiele, Bart De Spiegeleer
The expression of certain bacterial genes is regulated in a cell-density dependent way, a phenomenon called quorum sensing. Both Gram-negative and Gram-positive bacteria use this type of communication, though the signal molecules (auto-inducers) used by them differ between both groups: Gram-negative bacteria use predominantly N-acyl homoserine lacton (AHL) molecules (autoinducer-1, AI-1) while Gram-positive bacteria use mainly peptides (autoinducer peptides, AIP or quorum sensing peptides). These quorum sensing molecules are not only involved in the inter-microbial communication, but can also possibly cross-talk directly or indirectly with their host...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28425948/characterization-of-n-acyl-homoserine-lactones-in-vibrio-tasmaniensis-lgp32-by-a-biosensor-based-uhplc-hrms-ms-method
#16
Léa Girard, Élodie Blanchet, Laurent Intertaglia, Julia Baudart, Didier Stien, Marcelino Suzuki, Philippe Lebaron, Raphaël Lami
Since the discovery of quorum sensing (QS) in the 1970s, many studies have demonstrated that Vibrio species coordinate activities such as biofilm formation, virulence, pathogenesis, and bioluminescence, through a large group of molecules called N-acyl homoserine lactones (AHLs). However, despite the extensive knowledge on the involved molecules and the biological processes controlled by QS in a few selected Vibrio strains, less is known about the overall diversity of AHLs produced by a broader range of environmental strains...
April 20, 2017: Sensors
https://www.readbyqxmd.com/read/28424524/hqia-a-novel-quorum-quenching-enzyme-which-expands-the-ahl-lactonase-family
#17
Marta Torres, Stéphane Uroz, Rafael Salto, Laure Fauchery, Emilia Quesada, Inmaculada Llamas
The screening of a metagenomic library of 250,000 clones generated from a hypersaline soil (Spain) allowed us to identify a single positive clone which confers the ability to degrade N-acyl homoserine lactones (AHLs). The sequencing of the fosmid revealed a 42,318 bp environmental insert characterized by 46 ORFs. The subcloning of these ORFs demonstrated that a single gene (hqiA) allowed AHL degradation. Enzymatic analysis using purified HqiA and HPLC/MS revealed that this protein has lactonase activity on a broad range of AHLs...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28414213/immobilization-and-stabilization-of-acylase-on-carboxylated-polyaniline-nanofibers-for-highly-effective-antifouling-application-via-quorum-quenching
#18
Jeongjoon Lee, Inseon Lee, Jahyun Nam, Dong Soo Hwang, Kyung-Min Yeon, Jungbae Kim
Acylase (AC) was immobilized and stabilized on carboxylated polyaniline nanofibers (cPANFs) for the development of antifouling nanobiocatalysts with high enzyme loading and stability. AC was immobilized via three different approaches: covalent attachment (CA), enzyme coating (EC), and magnetically separable enzyme precipitate coating (Mag-EPC). The enzyme activity per unit weight of cPANFs with Mag-EPC was 75 and 300 times higher than that of those with CA and EC, respectively, representing improved enzyme loading in the form of Mag-EPC...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28413760/synthesis-of-c2-symmetric-diphosphormonoamidites-and-their-use-as-ligands-in-rh-catalyzed-hydroformylation-relationships-between-activity-and-hydrolysis-stability
#19
Galina Morales Torres, Stephan Behrens, Dirk Michalik, Detlef Selent, Anke Spannenberg, Susan Lühr, Katrin Marie Dyballa, Robert Franke, Armin Börner
A series of diphosphoramidites has been synthetized with a piperazine, homopiperazine, and an acyclic 1,2-diamine unit in the backbone. New compounds were tested alongside related N-acyl phosphoramidites as ligands in the Rh-catalyzed hydroformylation of n-octenes to investigate their influence on the activity and regioselectivity. A subsequent study of their hydrolysis stability revealed that the most stable ligands induced the highest activity in the catalytic reaction.
April 2017: ChemistryOpen
https://www.readbyqxmd.com/read/28413263/intensified-microwave-assisted-n-acylation-procedure-synthesis-and-activity-evaluation-of-trpc3-channel-agonists-with-a-1-3-dihydro-2h-benzo-d-imidazol-2-one-core
#20
Gema Guedes de la Cruz, Barbora Svobodova, Michaela Lichtenegger, Oleksandra Tiapko, Klaus Groschner, Toma Glasnov
Upon controlled microwave heating and using cyanuric chloride as a coupling reagent, an efficient amidation procedure for the synthesis of 1,3-dihydro-2H-benzo[d]imidazol-2-one-based agonists of TRPC3/6 ion channels has been developed. Compared to the few conventional protocols, a drastic reduction in processing time from ca. 2 days down to 10 minutes was achieved accompanied by significantly improved product yields. The robustness of the method was confirmed by 18 additional examples including aromatic, aliphatic, and heterocyclic amines and acids...
April 2017: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry
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