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https://www.readbyqxmd.com/read/28822572/enantiodifferentiation-of-whisky-and-cognac-lactones-using-gas-chromatography-with-different-cyclodextrin-chiral-stationary-phases
#1
Hans-Georg Schmarr, Maximilian Mathes, Kristina Wall, Frank Metzner, Marius Fraefel
The chiral lactone 5-butyl-4-methyloxolan-2-one or 5-butyl-4-methyldihydro-2(3H)-furanone, often named whisky lactone, is found in oak wood, then contributing to the appreciated flavor of beverages stored in such wooden barrels. Its next higher homologue is named cognac lactone (5-pentyl-4-methyloxolan-2-one or 5-pentyl-4-methyldihydro-2(3H)-furanone), however is much less known, probably due to its minor concentration level. In order to study the direct enantioseparation of both lactones by gas chromatography on chiral stationary phases, individual enantiomers, particularly for cognac lactone were made available...
August 5, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28822035/identification-and-functional-characterization-of-a-p-coumaroyl-coa-2-hydroxylase-involved-in-the-biosynthesis-of-coumarin-skeleton-from-peucedanum-praeruptorum-dunn
#2
Ruolan Yao, Yucheng Zhao, Tingting Liu, Chuanlong Huang, Sheng Xu, Ziwei Sui, Jun Luo, Lingyi Kong
A p-coumaroyl CoA 2'-hydroxylase responsible for the formation of coumarin lactone ring was identified from Peucedanum praeruptorum Dunn and functionally characterized in vitro. Coumarins are important plant secondary metabolites with a variety of biological activities. Ortho-hydroxylation of cinnamates leads to the formation of coumarin lactone ring and is generally thought to be a key step in coumarin biosynthesis. However, ortho-hydroxylases, especially p-coumaroyl CoA 2'-hydroxylase (C2'H) responsible for the biosynthesis of the most common coumarin skeleton, have received insufficient attention...
August 18, 2017: Plant Molecular Biology
https://www.readbyqxmd.com/read/28821734/transcriptional-transitions-in-alphonso-mango-mangifera-indica-l-during-fruit-development-and-ripening-explain-its-distinct-aroma-and-shelf-life-characteristics
#3
Ashish B Deshpande, Krishanpal Anamika, Vineet Jha, Hemangi G Chidley, Pranjali S Oak, Narendra Y Kadoo, Keshav H Pujari, Ashok P Giri, Vidya S Gupta
Alphonso is known as the "King of mangos" due to its unique flavor, attractive color, low fiber pulp and long shelf life. We analyzed the transcriptome of Alphonso mango through Illumina sequencing from seven stages of fruit development and ripening as well as flower. Total transcriptome data from these stages ranged between 65 and 143 Mb. Importantly, 20,755 unique transcripts were annotated and 4,611 were assigned enzyme commission numbers, which encoded 142 biological pathways. These included ethylene and flavor related secondary metabolite biosynthesis pathways, as well as those involved in metabolism of starch, sucrose, amino acids and fatty acids...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821212/characterization-of-syntrophic-geobacter-communities-using-tof-sims
#4
Wenchao Wei, Yanyan Zhang, Rachel Komorek, Andrew Plymale, Rujia Yu, Bingchen Wang, Zihua Zhu, Fanghua Liu, Xiao-Ying Yu
The aggregation of syntrophic Geobacter metallireducens and Geobacter sulfurreducens is beneficial for enhancing direct interspecies electron transfer (DIET). Although DIET was suspected to occur on the microbial community surface, the surface chemical speciation of such cocultured communities remains unclear. In order to better understand surface interactions related to DIET, the authors characterized a series of samples associated with syntrophic G. metallireducens and G. sulfurreducens using surface sensitive time-of-flight secondary ion mass spectrometry (ToF-SIMS)...
August 18, 2017: Biointerphases
https://www.readbyqxmd.com/read/28820600/magnesiate-addition-ring-expansion-strategy-to-access-the-6-7-6-tricyclic-core-of-hetisine-type-c20-diterpenoid-alkaloids
#5
Jason J Pflueger, Louis C Morrill, Justine N deGruyter, Melecio A Perea, Richmond Sarpong
A synthetic strategy to access the fused 6-7-6 tricyclic core of hetisine-type C20-diterpenoid alkaloids is reported. This strategy employs a Diels-Alder cycloaddition to assemble a fused bicyclic anhydride intermediate, which is elaborated to a vinyl lactone-acetal bearing an aromatic ring in five steps. Aromatic iodination is followed by magnesium-halogen exchange with a trialkyl magnesiate species, which undergoes intramolecular cyclization. Subsequent oxidation provides the desired 6-7-6 tricyclic diketoaldehyde, with carbonyl groups at all three positions for eventual C-N bond formation and subsequent elaboration...
August 18, 2017: Organic Letters
https://www.readbyqxmd.com/read/28820177/simple-%C3%AE-lactones-are-potent-irreversible-antagonists-for-strigolactone-receptors
#6
Haibo Xiang, Ruifeng Yao, Tianfei Quan, Fei Wang, Li Chen, Xiaoxi Du, Wenhao Zhang, Haiteng Deng, Daoxin Xie, Tuoping Luo
No abstract text is available yet for this article.
August 18, 2017: Cell Research
https://www.readbyqxmd.com/read/28819661/a-computational-study-of-the-influence-of-methyl-substituents-on-competitive-ring-closure-to-%C3%AE-and-%C3%AE-lactones
#7
Philippe B Wilson, Ian H Williams
Ring-closure of substituted 2-chlorosuccinates to α- or β-lactones has been studied by means of MP2/6-311+G(d,p)//MP2/6-31+G(d) calculations in water treated as a polarised continuum (PCM) and in vacuum. Optimised geometries have been obtained for 2-chlorosuccinate and its 2-methyl, 3,3-dimethyl, and 2,3,3-trimethyl derivatives, along with the transition structures and products for intramolecular nucleophilic displacement leading to the 3- or 4-membered rings. Relative enthalpies and Gibbs free energies of activation and reaction are presented, along with key geometrical parameters, and changes in electrostatic-potential-derived atomic charges...
August 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28819178/curcumin-liposomes-interfere-with-quorum-sensing-system-of-aeromonas-sobria-and-in-silico-analysis
#8
Ting Ding, Tingting Li, Zhi Wang, Jianrong Li
Aeromonas sobria is opportunistic pathogen frequently found in environment and food. Interfering with its quorum sensing (QS) system could be a promising way to alleviate its virulence. In this study, curcumin liposomes were prepared and their characteristics like particle size, zeta potential, PDI (Polymey Disperse Index), encapsulation efficiency and loading capacity were measured. The quorum sensing inhibitory effect of curcumin liposomes under sub-MIC (Minimum Inhibitory Concentration) on siderophore production, swimming and swarming motility, extracellular proteases, biofilm formation and AHLs (N-acylhomoserine lactones) production of A...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818490/inhibition-of-quorum-sensing-controlled-biofilm-formation-in-pseudomonas-aeruginosa-by-quorum-sensing-inhibitors
#9
Kalaiarasan Ellappan, Kottha Thirumalaswamy, Belgode Narasimha Harish, Gnanasambandam Vasuki, Veeresh Kumar Sali, James John
Antimicrobial therapy against extensively drug-resistant (XDR) P. aeruginosa biofilms is less efficient compared to the treatment of equal bacterial counts of free-floating planktonic cells, which has become a serious threat in hospital environment. P. aeruginosa regulate their cooperative activities and physiological process through a cell to cell chemical communication process called Quorum sensing (QS). This attracted our interest to synthesize, and to chemically characterize two anti-QS compounds, N-(4-{4-fluoroanilno} butanoyl) -L-homoserine lactone (FABHL) and N-(4-{4-chlororoanilno} butanoyl) -L-homoserine lactone (CABHL) to inhibit biofilm formation via disabling the QS circuits...
August 14, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28817970/three-new-cassane-diterpenes-from-the-seeds-of-caesalpinia-minax-hance
#10
Qin Liu, Bai Bai, De-Po Yang, Shi-Yi Peng, Long-Ping Zhu, Mai-Hui Luo, Zhi-Min Zhao
Four fractions were prepared from the crude extract of Caesalpinia minax Hance and the inhibitory activity of nitric oxide (NO) production release of RAW 264.7 cells stimulated by lipopolysaccharide (LPS) was evaluated. The ethyl acetate (EtOAc) fraction showed obvious inhibitory effect. Bioassay-guided fractionation led to the isolation of three new cassane diterpenes, caesalmin X (1), caesalmin Y (2) and caesalmin Z (3), together with 19 known cassane diterpenoids (4-22). Their structures were mainly characterised on the basis of extensive spectroscopic analyses and comparison with reported data...
August 18, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28816626/comparison-of-the-elution-characteristics-of-individual-forms-of-lovastatin-in-both-isocratic-and-gradient-modes-and-hplc-pda-method-development-for-pure-and-fermentation-derived-lovastatin
#11
Seenivasan Ayothiraman, Sathyanarayana N Gummadi, Tapobrata Panda
The elution characteristics of lovastatin were studied on varying the composition of mobile phase in both isocratic and gradient elution modes to comprehend the role of organic modifier and acidifier on the overall analysis time and retention time of individual forms of lovastatin. Acetonitrile has influenced on the overall analysis time, whereas the acidifier determines the retention time of hydroxy acid form of lovastatin and the retention time gap between the individual forms. A combination of acetonitrile and 0...
August 17, 2017: Preparative Biochemistry & Biotechnology
https://www.readbyqxmd.com/read/28814865/in-vitro-and-in-vivo-evaluation-of-sn-38-nanocrystals-with-different-particle-sizes
#12
Min Chen, Wanqing Li, Xun Zhang, Ye Dong, Yabing Hua, Hui Zhang, Jing Gao, Liang Zhao, Ying Li, Aiping Zheng
7-Ethyl-10-hydroxycamptothecin (SN-38) is a potent broad-spectrum antitumor drug derived from irinotecan hydrochloride (CPT-11). Due to its poor solubility and instability of the active lactone ring, its clinical use is significantly limited. As one of the most promising formulations for poorly water-soluble drugs, nanocrystals have attracted increasing attention. In order to solve these problems and evaluate the antitumor effect of SN-38 in vitro and in vivo, two nanocrystals with markedly different particle sizes were prepared...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28814794/increased-body-exposure-to-new-anti-trypanosomal-through-nanoencapsulation
#13
Renata Tupinambá Branquinho, Gwenaelle Pound-Lana, Matheus Marques Milagre, Dênia Antunes Saúde-Guimarães, José Mário Carneiro Vilela, Margareth Spangler Andrade, Marta de Lana, Vanessa Carla Furtado Mosqueira
Lychnopholide, a lipophilic sesquiterpene lactone, is efficacious in mice at the acute and chronic phases of Chagas disease. Conventional poly-ε-caprolactone (PCL) and long-circulating poly(D,L-lactide)-block-polyethylene glycol (PLA-PEG) nanocapsules containing lychnopholide were developed and characterized. Lychnopholide presented high association efficiency (>90%) with the nanocapsules. A new, fast and simple HPLC-UV-based bioanalytical method was developed, validated in mouse plasma and applied to lychnopholide quantification in in vitro release kinetics and pharmacokinetics...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814755/membrane-fouling-induced-by-ahl-mediated-soluble-microbial-product-smp-formation-by-fouling-causing-bacteria-co-cultured-with-fouling-enhancing-bacteria
#14
So Ishizaki, Ryoichi Sugiyama, Satoshi Okabe
Membrane fouling still remains a major obstacle for wider applications of membrane bioreactor (MBR), which is mainly caused by soluble microbial products (SMP). Identification of key bacteria responsible for SMP production is essential for mitigation of membrane fouling. Here, we investigated the effect of microbial interaction on membrane fouling. We measured the membrane fouling potentials of 13 bacterial strains isolated from a pilot-scale MBR treating domestic wastewater when they were cultivated as single-culture and co-culture...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28813020/nine-new-triterpene-glycosides-magnumosides-a%C3%A2-a%C3%A2-b%C3%A2-b%C3%A2-c%C3%A2-c%C3%A2-and-c%C3%A2-from-the-vietnamese-sea-cucumber-neothyonidium-massinium-magnum-structures-and-activities-against-tumor-cells-independently-and-in-synergy-with-radioactive-irradiation
#15
Alexandra S Silchenko, Anatoly I Kalinovsky, Sergey A Avilov, Vladimir I Kalinin, Pelageya V Andrijaschenko, Pavel S Dmitrenok, Ekaterina A Chingizova, Svetlana P Ermakova, Olesya S Malyarenko, Tatyana N Dautova
Nine new sulfated triterpene glycosides, magnumosides A₁ (1), A₂ (2), A₃ (3), A₄ (4), B₁ (5), B₂ (6), C₁ (7), C₂ (8) and C₄ (9) as well as a known colochiroside B₂ (10) have been isolated from the tropical Indo-West Pacific sea cucumber Neothynidium (=Massinium) magnum (Phyllophoridae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of new glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. All the isolated new glycosides were characterized by the non-holostane type lanostane aglycones having 18(16)-lactone and 7(8)-double bond and differed from each other by the side chains and carbohydrate moieties structures...
August 16, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28812898/enantioselective-n-heterocyclic-carbene-catalyzed-synthesis-of-functionalized-indenes
#16
Changhe Zhang, David W Lupton
An enantioselective NHC (N-heterocyclic carbene) catalyzed synthesis of indenes from bifunctional α,β-unsaturated acyl fluorides and TMS enol ethers has been discovered. The reaction has broad generality (31 examples) and proceeds with high levels of enantioselectivity (most >92:8 er). Mechanistically the reaction likely occurs via a Michael/β-lactonization/decarboxylation sequence. Derivatization studies and limitations are discussed.
August 16, 2017: Organic Letters
https://www.readbyqxmd.com/read/28812364/catalytic-asymmetric-desymmetrization-of-cyclopentendiones-via-diels-alder-reaction-of-3-hydroxy-2-pyrones-construction-of-multifunctional-bridged-tricyclic-lactones
#17
Li-Min Shi, Wu-Wei Dong, Hai-Yan Tao, Xiu-Qin Dong, Chun-Jiang Wang
An unprecedented asymmetric Diels-Alder reaction of 3-hydroxy-2-pyrones with prochiral cyclopentene-1,3-diones via desymmetrization was efficiently realized with high stereoselective control with the aid of fine-tunable cinchona alkaloid derived bifunctional amine-thiourea catalysts bearing multiple hydrogen-bonding donors. This protocol provides an expedient access to the multifunctional-bridged tricyclic lactones featuring four contiguous stereogenic centers and one remote quaternary stereogenic center with a broad substrate scope...
August 16, 2017: Organic Letters
https://www.readbyqxmd.com/read/28809836/nanosponge-tunability-in-size-and-crosslinking-density
#18
Laken L Kendrick-Williams, Eva Harth
We describe a protocol for the synthesis of linear polyesters containing pendant epoxide functionality and their incorporation into a nanosponge with controlled dimensions. This approach begins with synthesis of a functionalized lactone which is key to the pendant functionalization of the resulting polymer. Valerolactone (VL) and allyl-valerolactone (AVL) are then copolymerized using ring-opening polymerization. Post-polymerization modification is then used to install an epoxide moiety on some or all of the pendant allyl groups...
August 4, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28809817/synthesis-and-physicochemical-characterization-of-the-process-related-impurities-of-eplerenone-an-antihypertensive-drug
#19
Iwona Dams, Agata Białońska, Piotr Cmoch, Małgorzata Krupa, Anita Pietraszek, Anna Ostaszewska, Michał Chodyński
Two unknown impurities were observed during the process development for multigram-scale synthesis of eplerenone (Inspra(®)). The new process-related impurities were identified and fully characterized as the corresponding (7β,11α,17α)-11-hydroxy- and (7α,11β,17α)-9,11-dichloroeplerenone derivatives 12a and 13. Seven other known but poorly described in the literature eplerenone impurities, including four impurities A, B, C and E listed in the European Pharmacopoeia 8.4 were also detected, identified and fully characterized...
August 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28809569/rh-catalyzed-conjugate-addition-of-aryl-and-alkenyl-boronic-acids-to-%C3%AE-methylene-%C3%AE-lactones-stereoselective-synthesis-of-trans-3-4-disubstituted-%C3%AE-lactones
#20
Christian A Malapit, Irungu K Luvaga, Donald R Caldwell, Nicholas K Schipper, Amy R Howell
A one-step preparation of 3,4-disubstituted β-lactones through Rh-catalyzed conjugate addition of aryl or alkenyl boronic acids to α-methylene-β-lactones is described. The operationally simple, stereoselective transformation provides a broad range of β-lactones from individual α-methylene-β-lactone templates. This methodology allowed for a direct, final-step C-3 diversification of nocardiolactone, an antimicrobial natural product.
August 15, 2017: Organic Letters
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