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https://www.readbyqxmd.com/read/27922187/tomentosin-induces-telomere-shortening-and-caspase-dependant-apoptosis-in-cervical-cancer-cells
#1
Nawel Merghoub, Hassan El Btaouri, Laila Benbacer, Saïd Gmouh, Chantal Trentesaux, Bertrand Brassart, Mohammed Attaleb, Claudie Madoulet, Thomas Wenner, Saaid Amzazi, Hamid Morjani, Mohamed El Mzibri
Tomentosin, a natural sesquiterpene lactone purified from of Inula viscosa L., was investigated for its anti-proliferative, telomere shortening and apoptotic effects on human cervical cancer HeLa and SiHa cell lines. Tomentosin was found to inhibit the growth of SiHa and HeLa cell lines in dose and time-dependent manner (IC50 values of 7.10 ± 0.78µM and 5.87 ± 0.36µM, respectively after 96h of treatment). As evidenced by TTAGGG telomere length assay, tomentosin target specifically the telomeric overhang lengthening...
December 6, 2016: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/27920529/synthetic-high-density-lipoproteins-for-delivery-of-10-hydroxycamptothecin
#2
Yue Yuan, Jian Wen, Jie Tang, Qiming Kan, Rose Ackermann, Karl Olsen, Anna Schwendeman
The purpose of this study was to develop a novel synthetic high-density lipoprotein (sHDL) nanoparticle delivery system for 10-hydroxycamptothecin (HCPT) for treatment of colon carcinoma. HDL is recognized by scavenger receptor B-I (SR-BI) over-expressed in colon carcinomas 5- to 35-fold relative to the human fibroblasts. The sHDL nanoparticles were composed of apolipoprotein A-I mimic peptide (5A) and contained 0.5%-1.5% (w/w) of HCPT. An optimized HCPT-sHDL formulation exhibited 0.7% HCPT loading with 70% efficiency with an average size of 10-12 nm...
2016: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/27919613/cellular-uptake-of-glucoheptoamidated-poly-amidoamine-pamam-g3-dendrimer-with-amide-conjugated-biotin-a-potential-carrier-of-anticancer-drugs
#3
Łukasz Uram, Magdalena Szuster, Aleksandra Filipowicz, Magdalena Zaręba, Elżbieta Wałajtys-Rode, Stanisław Wołowiec
In search for soluble derivatives of PAMAM dendrimers as potential carriers for hydrophobic drugs, the conjugates of PAMAM G3 with biotin, further converted into glycodendrimer with d-glucoheptono-1,4-lactone, were prepared. Polyamidoamine dendrimer (PAMAM) of third generation, G3 was functionalized with four biotin equivalents covalently attached to terminal amine nitrogens via amide bond G3(4B). The remaining 28 amine groups were blocked by glucoheptoamide substituents (gh) to give G3(4B28gh) or with one fluorescein equivalent (attached by reaction of G3(4B) with fluorescein isothiocyanate, FITC) via thiourea bond as FITC followed by exhaustive glucoheptoamidation to get G3(4B27gh1F)...
November 25, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/27917168/the-absence-of-the-n-acyl-homoserine-lactone-autoinducer-synthase-genes-trai-and-ngri-increases-the-copy-number-of-the-symbiotic-plasmid-in-sinorhizobium-fredii-ngr234
#4
Jessica Grote, Dagmar Krysciak, Katrin Petersen, Simon Güllert, Christel Schmeisser, Konrad U Förstner, Hari B Krishnan, Harald Schwalbe, Nina Kubatova, Wolfgang R Streit
Plant-released flavonoids induce the transcription of symbiotic genes in rhizobia and one of the first bacterial responses is the synthesis of so called Nod factors. They are responsible for the initial root hair curling during onset of root nodule development. This signal exchange is believed to be essential for initiating the plant symbiosis with rhizobia affiliated with the Alphaproteobacteria. Here, we provide evidence that in the broad host range strain Sinorhizobium fredii NGR234 the complete lack of quorum sensing molecules results in an elevated copy number of its symbiotic plasmid (pNGR234a)...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27916690/acyl-homoserine-lactone-changes-the-abundance-of-proteins-and-the-levels-of-organic-acids-associated-with-stationary-phase-in-salmonella-enteritidis
#5
Felipe Alves de Almeida, Natan de Jesus Pimentel Filho, Lanna Clícia Carrijo, Cláudia Braga Pereira Bento, Maria Cristina Baracat-Pereira, Uelinton Manoel Pinto, Leandro Licursi de Oliveira, Maria Cristina Dantas Vanetti
Quorum sensing (QS) is cell-cell communication mechanism mediated by signaling molecules known as autoinducers (AIs) that lead to differential gene expression. Salmonella is unable to synthesize the AI-1 acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. Our study aimed to evaluate the influence of AI-1 on the abundance of proteins and the levels of organic acids of Salmonella Enteritidis. The presence of N-dodecyl-homoserine lactone (C12-HSL) did not interfere on the growth or the total amount of extracted proteins of Salmonella...
December 1, 2016: Microbial Pathogenesis
https://www.readbyqxmd.com/read/27915195/hydrogen-deuterium-exchange-a-unique-and-effective-method-for-ms-fragmentation-behavior-elucidation-of-ginkgolides-and-its-application-to-systematic-research-in-ginkgo-biloba
#6
Xingliang Niu, Jun Luo, Deran Xu, Hongyan Zou, Lingyi Kong
Ginkgolides, the main active constituents of Ginkgo biloba, possess significant selectively inhibition on platelet-activating factor and pancreatic lipase and attract wide attention in pharmacological research area. In our study, an effective hydrogen/deuterium (H/D) exchange method was developed by exchanging the α-Hs of lactone groups in ginkgolides with Ds, which was very useful for the elucidation of the fragmentation patterns of ginkgolides in Quadrupole Time-of-flight Mass Spectrometry (Q-TOF-MS), especially in accurately distinguishing the type and position of substituent in framework of ginkgolides...
November 26, 2016: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/27913172/efficient-catalytic-system-for-the-direct-transformation-of-lignocellulosic-biomass-to-furfural-and-5-hydroxymethylfurfural
#7
Luxin Zhang, Guoyun Xi, Jiaxin Zhang, Hongbing Yu, Xiaochang Wang
A feasible approach was developed for the co-production of 5-hydroxymethylfurfural (5-HMF) and furfural from corncob via a new porous polytriphenylamine-SO3H (SPTPA) solid acid catalyst in lactone solvents. XRD, SEM, XPS, N2 adsorption-desorption, elemental analysis, TG-DTA, acid-base titration and FTIR spectroscopy techniques were used to characterize the catalyst. This study demonstrates and optimizes the catalytic performance of SPTPA and solvent selection. SPTPA was found to exhibit superior catalytic ability in γ-valerolactone (GVL)...
November 25, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/27911925/attenuation-of-quorum-sensing-regulated-virulence-of-pectobacterium-carotovorum-subsp-carotovorum-through-an-ahl-lactonase-produced-by-lysinibacillus-sp-gs50
#8
Sneha S Garge, Anuradha S Nerurkar
Quorum sensing (QS) is a mechanism in which Gram negative bacterial pathogens sense their population density through acyl homoserine lactones (AHLs) and regulate the expression of virulence factors. Enzymatic degradation of AHLs by lactonases, known as quorum quenching (QQ), is thus a potential strategy for attenuating QS regulated bacterial infections. We characterised the QQ activity of soil isolate Lysinibacillus sp. Gs50 and explored its potential for controlling bacterial soft rot of crop plants. Lysinibacillus sp...
2016: PloS One
https://www.readbyqxmd.com/read/27909432/volatile-mediated-effects-predominate-in-paraburkholderia-phytofirmans-growth-promotion-and-salt-stress-tolerance-of-arabidopsis-thaliana
#9
Thomas Ledger, Sandy Rojas, Tania Timmermann, Ignacio Pinedo, María J Poupin, Tatiana Garrido, Pablo Richter, Javier Tamayo, Raúl Donoso
Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27909352/solid-phase-extraction-of-tritiated-contaminants-from-tritium-containing-waste-oils
#10
Andrzej Olejniczak, Jacek Fall, Katarzyna Olejniczak, Marina V Gustova, Alexandr G Shostenko
A solid phase extraction method for removing polar tritiated contaminants from tritium-containing waste oils has been developed. The composition of the degradation products present in the waste oil was determined. The results indicated that upon exposure to tritium gas, fragment methyl ketones, carboxylic acids, and lactones were the main polar products of the mineral-based oil oxidation. The nonpolar fragmentation products included n-alkanes, monomethylalkanes, and acyclic isoprenoids and were analogous to those formed during [Formula: see text]-irradiation of the oil...
2016: Journal of Radioanalytical and Nuclear Chemistry
https://www.readbyqxmd.com/read/27909291/engineering-of-a-thermostable-esterase-est816-to-improve-its-quorum-quenching-activity-and-the-underlying-structural-basis
#11
Xiwen Liu, Li-Chuang Cao, Xin-Jiong Fan, Yu-Huan Liu, Wei Xie
N-acyl-homoserine lactones (AHLs) are small diffusible molecules called autoinducers that mediate cell-to-cell communications. Enzymatic degradation of AHLs is a promising bio-control strategy known as quorum-quenching. To improve the quorum-quenching activity of a thermostable esterase Est816, which had been previously cloned, we have engineered the enzyme by random mutagenesis. One of the mutants M2 with double amino acid substitutions (A216V/K238N) showed 3-fold improvement on catalytic efficiency. Based on the crystal structure determined at 2...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27906488/total-synthesis-of-leupyrrins-a1-and-b1-highly-potent-antifungal-agents-from-the-myxobacterium-sorangium-cellulosum
#12
Sebastian Thiede, Paul R Wosniok, Daniel Herkommer, Thomas Debnar, Maoqun Tian, Tongtong Wang, Michael Schrempp, Dirk Menche
Full details on the design, elaboration and application of efficient strategies for the high-yielding total syntheses of leupyrrins A1 and B1, unique antifungal agents from the myxobacterium Sorangium cellulosum are reported. A sequential zirconocene-mediated diyne-cyclization and regioselective opening of the zirconacyclopentadiene intermediate enabled a concise entry into the unique dihydrofuran fragment, while another domino reaction was developed for the butyrolactone involving a one-pot lactol opening, stereoselective aldehyde addition and in situ-lactonization...
December 1, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27905512/plant-phenolic-volatiles-inhibit-quorum-sensing-in-pectobacteria-and-reduce-their-virulence-by-potential-binding-to-expi-and-expr-proteins
#13
Janak Raj Joshi, Netaly Khazanov, Hanoch Senderowitz, Saul Burdman, Alexander Lipsky, Iris Yedidia
Quorum sensing (QS) is a population density-dependent regulatory system in bacteria that couples gene expression to cell density through accumulation of diffusible signaling molecules. Pectobacteria are causal agents of soft rot disease in a range of economically important crops. They rely on QS to coordinate their main virulence factor, production of plant cell wall degrading enzymes (PCWDEs). Plants have evolved an array of antimicrobial compounds to anticipate and cope with pathogens, of which essential oils (EOs) are widely recognized...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27902410/inhibition-of-quorum-sensing-controlled-virulence-factors-of-pseudomonas-aeruginosa-by-murraya-koenigii-essential-oil-a-study-in-a-caenorhabditis-elegans-infectious-model
#14
P Sankar Ganesh, Ravishankar Vittal Rai
The global emergence of antibiotic resistant strains of Pseudomonas aeruginosa poses a major threat in hospital environments as well as in the community. P. aeruginosa is an opportunistic human pathogen and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation which are crucial for establishment of the infection...
November 3, 2016: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/27901163/synthesis-and-biological-evaluation-of-simplified-pironetin-analogues-with-modifications-in-the-side-chain-and-the-lactone-ring
#15
Steven Roldán, Adrià Cardona, Laura Conesa, Juan Murga, Eva Falomir, Miguel Carda, J Alberto Marco
The preparation of several new analogues of the natural dihydropyrone pironetin is described. They differ from the natural product mainly in the nature of the side chain and the lactone ring. Their cytotoxic activity has been measured. In addition, their interaction with tubulin, their ability to inhibit the secretion of the vascular endothelial growth factor (VEGF) and the expression of angiogenesis and telomerase-related genes have been determined. Unexpectedly, and unlike pironetin, the lactones studied in this work do not interact with tubulin...
November 30, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27900837/organocatalytic-friedel-crafts-alkylation-lactonization-reaction-of-naphthols-with-3-trifluoroethylidene-oxindoles-the-asymmetric-synthesis-of-dihydrocoumarins
#16
Yun-Long Zhao, Qin-Xin Lou, Long-Sheng Wang, Wen-Hui Hu, Jun-Ling Zhao
Naphthols and 3-trifluoroethylidene oxindoles were found to undergo an asymmetric Friedel-Crafts alkylation/lactonization reaction, catalyzed by only 2.5 mol % of a quinine-derived squaramide catalyst, to afford the corresponding α-aryl-β-trifluoromethyl dihydrocoumarin derivatives in high yields (up to 99 %) with excellent enantio- and diastereoselectivities (up to 98 % ee, >20:1 d.r.). Importantly, the lactonization proceeded by nucleophilic attack of the naphthol hydroxy group at the amide motif of the oxindoles under mild reaction conditions...
November 30, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27900697/screening-for-n-ahsl-based-signaling-interfering-enzymes
#17
Stéphane Uroz, Phil M Oger
Quorum sensing (QS)-based signaling is a widespread pathway used by bacteria for the regulation of functions involved in their relation to the environment or their host. QS relies upon the production, accumulation and perception of small diffusable molecules by the bacterial population, hence linking high gene expression with high cell population densities. Among the different QS signal molecules, an important class of signal molecules is the N-acyl homoserine lactone (N-AHSL). In pathogens such as Erwinia or Pseudomonas, N-AHSL based QS is crucial to overcome the host defenses and ensure a successful infection...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27900439/non-ribosomal-peptide-synthases-from-pseudomonas-aeruginosa-play-a-role-in-cyclodipeptide-biosynthesis-quorum-sensing-regulation-and-root-development-in-a-plant-host
#18
Omar González, Randy Ortíz-Castro, César Díaz-Pérez, Alma L Díaz-Pérez, Viridiana Magaña-Dueñas, José López-Bucio, Jesús Campos-García
Diverse molecules mediate cross-kingdom communication between bacteria and their eukaryotic partners and determine pathogenic or symbiotic relationships. N-acyl-L-homoserine lactone-dependent quorum-sensing signaling represses the biosynthesis of bacterial cyclodipeptides (CDPs) that act as auxin signal mimics in the host plant Arabidopsis thaliana. In this work, we performed bioinformatics, biochemical, and plant growth analyses to identify non-ribosomal peptide synthase (NRPS) proteins of Pseudomonas aeruginosa, which are involved in CDP synthesis...
November 30, 2016: Microbial Ecology
https://www.readbyqxmd.com/read/27896412/the-bacterial-quorum-sensing-molecule-n-3-oxo-dodecanoyl-l-homoserine-lactone-inhibits-mediator-release-and-chemotaxis-of-murine-mast-cells
#19
Ibrahim Khambati, Sangsu Han, Daniëlle Pijnenburg, Hannah Jang, Paul Forsythe
OBJECTIVE: Bacterial colonization relies on communication between bacteria via so-called "quorum-sensing molecules", which include the acyl-homoserine lactone group. Certain acyl-homoserine lactones can modulate mammalian cell function and are thought to contribute to bacterial pathogenicity. Given the role of mast cells in host defense, we investigated the ability of acyl-homoserine lactones to modulate mast cell function. METHODS: We utilized murine primary mast cell cultures to assess the effect of acyl-homoserine lactones on degranulation and cytokine release in response to different stimuli...
November 28, 2016: Inflammation Research: Official Journal of the European Histamine Research Society ... [et Al.]
https://www.readbyqxmd.com/read/27893812/solid-phase-synthesis-of-%C3%A9-lactone-and-1-2-oxazine-derivatives-and-their-efficient-chiral-analysis
#20
Sona Krupkova, Gonzalo Pazos Aguete, Leona Kocmanova, Tereza Volna, Martin Grepl, Lucie Novakova, Marvin John Miller, Jan Hlavac
Derivatives of 3-methyl-3,6-dihydro-2H-1,2-oxazine-6-carboxylic acid prepared by regioselective hetero Diels-Alder reaction of arylnitroso compounds with sorbic acid were used for solid-phase synthesis of a library of derivatives that included modification of carboxylic group, dihydroxylation of double bond and cleavage of N-O bond. Derivatives of 2,3,4-trihydroxyhexanoic acid obtained from 3,6-dihydro-2H-1,2-oxazines after double bond dihydroxylation and N-O cleavage were used for simple and stereoselective formation of chiral lactones derived from 3,4-dihydroxydihydrofuran-2(3H)-one...
2016: PloS One
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