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https://www.readbyqxmd.com/read/28817258/synthesis-of-complex-glycolates-by-enantioconvergent-addition-reactions
#1
Samuel L Bartlett, Jeffrey S Johnson
The unique role that stereochemistry plays in molecular recognition events continues to provide a driving force for synthesizing organic compounds in enantioenriched form. The tendency of enantioenriched organic compounds to revert to an entropically favored racemic state in the presence of viable racemization pathways (e.g., the enolization of stereogenic carbonyl derivatives) can sometimes interfere with this objective; however, beginning with Noyori's foundational disclosure of a dynamic kinetic transfer hydrogenation, the ability to channel racemic, configurationally labile starting materials through stereoconvergent reaction pathways has been recognized as a powerful strategy in asymmetric synthesis...
August 17, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28816406/phosphinous-acid-assisted-hydration-of-nitriles-understanding-the-controversial-reactivity-of-osmium-and-ruthenium-catalysts
#2
Rebeca González-Fernández, Pascale Crochet, Victorio Cadierno, M Isabel Menéndez, Ramón López
The synthesis and catalytic behaviour of the osmium(II) complexes [OsCl2(6-p-cymene)(PR2OH)] [R = Me (2a), Ph (2b), OMe (2c), OPh (2d)] in nitrile hydration reactions is presented. Among them, the best catalytic results were obtained with the phosphinous acid derivative [OsCl2(6-p-cymene)(PMe2OH)] (2a), which selectively provided the desired primary amides in excellent yields and short times at 80 ºC, employing directly water as solvent, and without the assistance of any basic additive (TOF values up to 200 h-1)...
August 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28813015/transcriptional-responses-of-creeping-bentgrass-to-2-3-butanediol-a-bacterial-volatile-compound-bvc-analogue
#3
Yi Shi, Kuiju Niu, Bingru Huang, Wenhui Liu, Huiling Ma
Bacterial volatile compounds (BVCs) have been reported to enhance plant growth and elicit plant defenses against fungal infection and insect damage. The objective of this study was to determine transcriptomic changes in response to synthetic BVC that could be associated with plant resistance to Rhizoctonia solani in creeping bentgrass. The 2,3-butanediol (BD) (250 µM) was sprayed on creeping bentgrass leaves grown in jam jars. The result showed that synthetic BD induced plant defense against R. solani for creeping bentgrass...
August 16, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28812261/backbone-and-side-chain-1-h-15-n-and-13-c-resonance-assignments-of-two-sac10b-family-members-mvo10b-and-mth10btqqa-from-archaea
#4
Jinsong Xuan, Hongwei Yao, Yingang Feng, Jinfeng Wang
The Sac10b family proteins, also named as Alba, are small, basic, nucleic acid-binding proteins widely distributed in archaea. They possess divergent physiological functions such as binding to both DNA and RNA with a high affinity and involving in genomic DNA compaction, RNA transactions and transcriptional regulations. The structures of many Sac10b family proteins from hyperthermophilic archaea have been reported, while those from thermophilic and mesophilic archaea are largely unknown. As was pointed out, the homologous members from thermophilic and mesophilic archaea may have functions different from the hyperthermophilic members...
August 16, 2017: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/28812027/l-theanine-administration-modulates-the-absorption-of-dietary-nutrients-and-expression-of-transporters-and-receptors-in-the-intestinal-mucosa-of-rats
#5
Qiongxian Yan, Haiou Tong, Shaoxun Tang, Zhiliang Tan, Xuefeng Han, Chuanshe Zhou
L-theanine has various advantageous functions for human health; whether or not it could mediate the nutrients absorption is unknown yet. The effects of L-theanine on intestinal nutrients absorption were investigated using rats ingesting L-theanine solution (0, 50, 200, and 400 mg/kg body weight) per day for two weeks. The decline of insulin secretion and glucose concentration in the serum was observed by L-theanine. Urea and high-density lipoprotein were also reduced by 50 mg/kg L-theanine. Jejunal and ileac basic amino acids transporters SLC7a1 and SLC7a9, neutral SLC1a5 and SLC16a10, and acidic SLC1a1 expression were upregulated...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28811021/quantitative-analysis-of-major-and-trace-elements-in-nh4hf2-modified-silicate-rock-powders-by-laser-ablation-inductively-coupled-plasma-mass-spectrometry
#6
Wen Zhang, Zhaochu Hu, Yongsheng Liu, Wenwu Yang, Haihong Chen, Shenghong Hu, Hongyan Xiao
In this paper, we described a NH4HF2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH4HF2 at 230 °C for 3 h form ultrafine powders with a typical grain size d80 < 8.5 μm, and various silicate rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder...
August 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28810832/genome-wide-analysis-of-basic-helix-loop-helix-bhlh-transcription-factors-in-brachypodium-distachyon
#7
Xin Niu, Yuxiang Guan, Shoukun Chen, Haifeng Li
BACKGROUND: As a superfamily of transcription factors (TFs), the basic helix-loop-helix (bHLH) proteins have been characterized functionally in many plants with a vital role in the regulation of diverse biological processes including growth, development, response to various stresses, and so on. However, no systemic analysis of the bHLH TFs has been reported in Brachypodium distachyon, an emerging model plant in Poaceae. RESULTS: A total of 146 bHLH TFs were identified in the Brachypodium distachyon genome and classified into 24 subfamilies...
August 15, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28810710/testing-convergent-evolution-in-auditory-processing-genes-between-echolocating-mammals-and-the-aye-aye-a-percussive-foraging-primate
#8
Richard J Bankoff, Michael Jerjos, Baily Hohman, M Elise Lauterbur, Logan Kistler, George H Perry
Several taxonomically distinct mammalian groups-certain microbats and cetaceans (e.g., dolphins)-share both morphological adaptations related to echolocation behavior and strong signatures of convergent evolution at the amino acid level across seven genes related to auditory processing. Aye-ayes (Daubentonia madagascariensis) are nocturnal lemurs with a specialized auditory processing system. Aye-ayes tap rapidly along the surfaces of trees, listening to reverberations to identify the mines of wood-boring insect larvae; this behavior has been hypothesized to functionally mimic echolocation...
July 1, 2017: Genome Biology and Evolution
https://www.readbyqxmd.com/read/28809961/biochemical-characterization-of-recombinant-influenza-a-polymerase-heterotrimer-complex-endonuclease-activity-and-evaluation-of-inhibitors
#9
Weimei Xing, Ona Barauskas, Thorsten Kirschberg, Anita Niedziela-Majka, Michael Clarke, Gabriel Birkus, Perry Weissburg, Xiaohong Liu, Brian E Schultz, Roman Sakowicz, HyockJoo Kwon, Joy Y Feng
Influenza polymerase is a heterotrimer composed of polymerase acidic protein A (PA) and basic proteins 1 (PB1) and 2 (PB2). The endonuclease active site, located in the PA subunit, cleaves host mRNA to prime viral mRNA transcription, and is essential for viral replication. To date, the human influenza A endonuclease activity has only been studied on the truncated active-site containing N-terminal domain of PA (PAN) or full-length PA in the absence of PB1 or PB2. In this study, we characterized the endonuclease activity of recombinant proteins of influenza A/PR8 containing full length PA, PA/PB1 dimer, and PA/PB1/PB2 trimer, observing 8...
2017: PloS One
https://www.readbyqxmd.com/read/28809545/plasmonic-nanoprobe-of-gold-triangular-nanoprism-core-polyaniline-shell-for-real-time-three-dimensional-ph-imaging-of-anterior-chamber
#10
Peijun Tang, Xueqin Jiang, Yangyang Wang, Huanjun Chen, Yu Shrike Zhang, Panpan Gao, Hao Wang, Xuemeng Li, Jianhua Zhou
Three-dimensional (3D) molecular imaging enables the study of biological processes in both living and nonviable systems at the molecular level and has a high potential on early diagnosis. In conjunction with specific molecular probes, optical coherent tomography (OCT) is a promising imaging modality to provide 3D molecular features at the tissue level. In this study, we introduced (gold-triangular-nanoprism-core)/(polyaniline-shell nanoparticles) (GTNPs@PANI) as an OCT contrast agent and pH-responsive nanoprobe for 3D imaging of pH distribution...
August 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28809474/a-nano-in-nano-approach-for-enzyme-immobilization-based-on-block-copolymers
#11
Finizia Auriemma, Claudio De Rosa, Anna Malafronte, Rocco Di Girolamo, Chiara Santillo, Yuri Gerelli, Giovanna Fragneto, Robert David Barker, Vincenzo Pavone, Ornella Maglio, Angela Lombardi
We have set-up a facile approach for fabrication of supports with tailored nanoporosity for immobilization of enzymes. To this aim block copolymers self-assembly has been used to prepare nanostructured thin films with well-defined architecture containing pores of tailorable size delimited by walls with tailorable degree of hydrophilicity. In particular, we have employed a mixture of polystyrene-block-poly(L-lactide) (PS-PLLA) and polystyrene-block-poly(ethylene oxide) (PS-PEO) diblock copolymers to generate thin films with a lamellar morphology consisting of PS lamellar do-mains alternating with mixed PEO/PLLA blocks lamellar domains...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28808380/identification-and-analysis-of-jasmonate-pathway-genes-in-coffea-canephora-robusta-coffee-by-in-silico-approach
#12
Kosaraju Bharathi, H L Sreenath
BACKGROUND: Coffea canephora is the commonly cultivated coffee species in the world along with Coffea arabica. Different pests and pathogens affect the production and quality of the coffee. Jasmonic acid (JA) is a plant hormone which plays an important role in plants growth, development, and defense mechanisms, particularly against insect pests. The key enzymes involved in the production of JA are lipoxygenase, allene oxide synthase, allene oxide cyclase, and 12-oxo-phytodienoic reductase...
July 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28805540/novel-approach-for-structural-identification-of-protein-family-glyoxalase-i
#13
Anton M Kargatov, Eugenia A Boshkova, Yuri N Chirgadze
Glyoxalase is one of two enzymes of the glyoxalase detoxification system against methylglyoxal and other aldehydes, the metabolites derived from glycolysis. The glyoxalase system is found almost in all living organisms: bacteria, protozoa, plants and animals, including humans, and is related to the class of "life essential proteins". The enzyme belongs to the expanded Glyoxalase/Bleomycin resistance protein/Dioxygenase superfamily. At present the GenBank contains about seven hundreds of amino acid sequences of this enzyme type, and the Protein Data Bank includes dozens of spatial structures...
August 14, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28804941/proteomic-analysis-to-unravel-the-effect-of-heat-stress-on-gene-expression-and-milk-synthesis-in-bovine-mammary-epithelial-cells
#14
Lian Li, Yiru Wang, Chengmin Li, Genlin Wang
Heat stress can play a negative effect on milk yield and composition of dairy cattle, leading to immeasurable economic loss. The basic components of the mammary gland are the alveoli; these alveolar mammary epithelial cells reflect the milk producing ability of dairy cows. In this study, we exposed bovine mammary epithelial cells to heat stress and compared them to a control group using isobaric tags for relative and absolute quantitation combined with liquid chromatography coupled with tandem mass spectrometry...
August 14, 2017: Animal Science Journal, Nihon Chikusan Gakkaihō
https://www.readbyqxmd.com/read/28803210/investigation-of-ph-and-substituent-effects-on-the-distribution-ratio-of-novel-steroidal-ring-d-and-a-fused-arylpyrazole-regioisomers-and-evaluation-of-their-cell-growth-inhibitory-effects-in-vitro
#15
Ádám Baji, Ferenc Kovács, Gergő Mótyán, Gyula Schneider, János Wölfling, Izabella Sinka, István Zupkó, Imre Ocsovszki, Éva Frank
Novel androstanopyrazoles have been efficiently synthesized from steroidal β-ketoaldehydes with different arylhydrazine hydrochlorides both under acidic and basic conditions. Knorr-type transformations of 16-hydroxymethylene-dehydroepiandrosterone containing its 1,3-dicarbonyl moiety on ring D, proved to be regioselective in pyridine at room temperature, while mixtures of regioisomers were obtained in acidic EtOH under reflux. Contrarily, the cyclocondensation reactions of 2-hydroxymethylene-dihydrotestosterone bearing its reactive functionalities on ring A, led to a mixture of pyrazole regioisomers in varying ratio depending on the applied medium...
August 9, 2017: Steroids
https://www.readbyqxmd.com/read/28802391/pathophysiology-of-esophageal-impairment-due-to-button-battery-ingestion
#16
Johannes Völker, Christine Völker, Philipp Schendzielorz, Sebastian P Schraven, Andreas Radeloff, Robert Mlynski, Rudolf Hagen, Kristen Rak
BACKGROUND: The increased use of button batteries with high energy densities in devices of daily life presents a high risk of injury, especially for toddlers and young children. If an accidental ingestion of a button battery occurs, this foreign body can become caught in the constrictions of the esophagus and cause serious damage to the adjacent tissue layers. The consequences can be ulcerations, perforations with fistula formation and damage to the surrounding anatomical structures. In order to gain a better understanding of the pathophysiology after ingestion, we carried out systematic studies on fresh preparations of porcine esophagi...
September 2017: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/28801803/the-adsorption-of-no-nh3-n2-on-carbon-surface-a-density-functional-theory-study
#17
Jiayong Wang, Mo Yang, Debing Deng, Shuxia Qiu
To explore the adsorption mechanism of NO, NH3, N2 on a carbon surface, and the effect of basic and acidic functional groups, density functional theory was employed to investigate the interactions between these molecules and carbon surfaces. Molecular electrostatic potential, Mulliken population analyses, reduced density gradient, and Mayer bond order analyses were used to clarify the adsorption mechanism. The results indicate that van der Waals interactions are responsible for N2 physisorption, and N2 is the least likely to adsorb on a carbon surface...
August 11, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28801675/targeting-p-glycoprotein-investigation-of-piperine-analogs-for-overcoming-drug-resistance-in-cancer
#18
Safiulla Basha Syed, Hemant Arya, I-Hsuan Fu, Teng-Kuang Yeh, Latha Periyasamy, Hsing-Pang Hsieh, Mohane Selvaraj Coumar
P-glycoprotein (P-gp) is a drug transporter that effluxes chemotherapeutic drugs and is implicated in the development of resistance of cancer cells to chemotherapeutic drugs. To date, no drug has been approved to inhibit P-gp and restore chemotherapy efficacy. Moreover, majority of the reported inhibitors have high molecular weight and complex structures, making it difficult to understand the basic structural requirement for P-gp inhibition. In this study, two structurally simple, low molecular weight piperine analogs Pip1 and Pip2 were designed and found to better interact with P-gp than piperine in silico...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28801044/cationic-ionic-liquid-surfactant-polyacrylamide-gel-electrophoresis-for-enhanced-separation-of-acidic-and-basic-proteins-with-single-step-ribonuclease-b-glycoforms-separation
#19
Punprabhashi Vidanapathirana, Farhana Hasan, Kaitlyn Mussio, Anuja Pande, Michael Brands, Noureen Siraj, Anne Grove, Isiah M Warner
Cationic ionic liquids-based surfactants (ILS), such as 4-methyl pyridinium bromide (CnPBr, where n=4,6,8), were used in preparation of polyacrylamide gels, sample buffer, and running buffer for cationic ILS polyacrylamide gel electrophoresis (ILS-PAGE). These ILS are liquids in the pure state and were selected for improved separation of ribonuclease b (Rib b) glycoforms in a single step and a protein mixture containing bovine serum albumin (BSA, pI-4.8, 66.5kDa), ovalbumin (Ova, pI-4.6, 44.3kDa), α-chymotrypsinogen (α-Chy, pI-8...
July 29, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28800973/critical-evaluation-of-dipolar-acid-base-and-charge-interactions-i-electron-displacement-within-and-between-molecules-liquids-and-semiconductors
#20
REVIEW
Jarl B Rosenholm
Specific dipolar, acid-base and charge interactions involve electron displacements. For atoms, single bonds and molecules electron displacement is characterized by electronic potential, absolute hardness, electronegativity and electron gap. In addition, dissociation, bonding, atomization, formation, ionization, affinity and lattice enthalpies are required to quantify the electron displacement in solids. Semiconductors are characterized by valence and conduction band energies, electron gaps and average Fermi energies which in turn determine Galvani potentials of the bulk, space charge layer and surface states...
June 21, 2017: Advances in Colloid and Interface Science
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