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Jing Guo, Lili Lin, Yangbin Liu, Xiangqiang Li, Xiaohua Liu, Xiaoming Feng
The enantioselective α-vinylation of β-keto amides/esters using hypervalent iodine salts has been accomplished via a chiral N,N'-dioxide-nickel(II) complex promoted electrophilic addition and reductive elimination process. A wide range of vinyl-substituted all-carbon quaternary β-keto amides/esters were obtained in high yields and ee values (up to 99% yield and 99% ee). Moreover, the catalytic system has been applied to the enantioselective alkynylation/arylation of β-ketoamides with good results.
October 25, 2016: Organic Letters
Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Hideko Koshima, Toru Asahi
Introducing chirality into photomechanical crystals is beneficial for the diversification of mechanical motion. Measurement of the chiroptical and optical anisotropic properties of chiral crystals is indispensable for evaluating photomechanical crystals. The plate-like crystals of S- and R-enantiomers of photochromic N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in enol form (enol-(S)-1 and enol-(R)-1) caused bending motion with twisting upon ultraviolet (UV) light irradiation, due to shrinkage along the length and width directions of the irradiated surface, based on the optimized crystal structure of the photoisomerized trans-keto-(S)-1...
October 24, 2016: Journal of the American Chemical Society
Marie Vayer, Weizhen Fang, Régis Guillot, Sophie Bezzenine-Lafollée, Christophe Bour, Vincent Gandon
1,3-Dienyl β-keto esters are cyclised into bicyclolactones using the Bi(OTf)3/TfOH catalytic system. This reaction represents a rare case of simultaneous C-C and C-O bond formation at positions 1 and 3 of a 1,3-diene. Application to the synthesis of ramulosin is presented.
October 24, 2016: Organic & Biomolecular Chemistry
Jian Hu, Qingmei Wang, Li Huang, Yuanqing Zeng, Zheng Hu, Dixian Luo
Objective To prepare rabbit anti-aldo-keto reductase family 1 member B10 (AKR1B10) polyclonal antibody and identify its specificity. Methods AKR1B10 cDNA was amplified by reverse transcription PCR (RT-PCR) and inserted into prokaryotic expression vector pET-15b to form recombinant plasmid pET-15b-AKR1B10. The recombinant plasmid pET-15b-AKR1B10 was transformed into E.coli DH5α. Isopropylthio-β-D-galactoside (IPTG) was used to induce the expression of the recombinant protein His-tagged AKR1B10 in E.coli DH5α...
November 2016: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
Purva P Bhojane, Michael R Duff, Khushboo Bafna, Gabriella P Rimmer, Pratul K Agarwal, Elizabeth E Howell
Folate, or vitamin B9, is an important compound in one carbon metabolism. Previous studies have found weaker binding of dihydrofolate to dihydrofolate reductase in the presence of osmolytes. In other words, osmolytes are more difficult to remove from the dihydrofolate solvation shell than water; this shifts the equilibrium towards the free ligand and protein species. This study uses vapor pressure osmometry to explore the interaction of folate with the model osmolyte, glycine betaine. This method yields a preferential interaction potential (μ23/RT value)...
October 21, 2016: Biochemistry
Raymond Kwok Kei Chow, Sarah Tsz-Kwan Sin, Ming Liu, Yan Li, Tim Hon Man Chan, Yangyang Song, Leilei Chen, Dora Lai-Wan Kwong, Xin-Yuan Guan
Hepatocellular carcinoma (HCC), which accounts for 85-90% of primary liver cancer, is now the second leading cause of cancer-related mortality worldwide. Here we reported that Aldo-Keto Reductase family 7A isoform 3 (AKR7A3) is frequently down-regulated in HCC, associating with poor overall survival rate, elevated serum α-fetoprotein (AFP) and poor differentiation of HCC. The promoter region of AKR7A3 was detected to be hypermethylated. Loss of heterozygosity (LOH) was also detected in AKR7A3. Functional assays on both AKR7A3 overexpressed and knockdown cells, including foci formation, colony formation in soft agar, migration, invasion and tumor formation in nude mice, demonstrated the strong tumor suppressive functions of AKR7A3...
October 18, 2016: Oncotarget
O Lidický, M Šírová, T Etrych
In this paper, we describe the synthesis, physicochemical characterization, drug release kinetics and preliminary biological evaluation of several N-(2-hydroxypropyl)methacrylamide (HPMA)-based polymer-retinoid conjugates designed for solid tumor immunotherapy. The conjugates are supposed to inhibit the immunosuppressive activity of myeloid-derived suppressor cells (MDSC) accumulated in the solid tumor microenvironment. All-trans retinoic acid (ATRA) was derivatized to hydrazide (AtrHy) and then attached to the polymer backbone via a spacer that is stable at the normal pH of blood (7...
October 20, 2016: Physiological Research
Matthias Ruckenbauer, Sebastian Mai, Philipp Marquetand, Leticia González
Time-resolved photoelectron spectroscopy is commonly employed with the intention to monitor electronic excited-state dynamics occurring in a neutral molecule. With the help of theory, we show that when excited-state processes occur on similar time scales the different relaxation pathways are completely obscured in the total photoionization signal recorded in the experiment. Using non-adiabatic molecular dynamics and Dyson norms, we calculate the photoionization signal of cytosine and disentangle the transient contributions originating from the different deactivation pathways of its tautomers...
October 20, 2016: Scientific Reports
Chaudhari Archana Somabhai, Ruma Raghuvanshi, G Nareshkumar
AIMS: To assess protective efficacy of genetically modified Escherichia coli Nissle 1917 (EcN) on metabolic effects induced by chronic consumption of dietary fructose. MATERIALS AND METHODS: EcN was genetically modified with fructose dehydrogenase (fdh) gene for conversion of fructose to 5-keto-D-fructose and mannitol-2-dehydrogenase (mtlK) gene for conversion to mannitol, a prebiotic. Charles foster rats weighing 150-200 g were fed with 20% fructose in drinking water for two months...
2016: PloS One
Nathan Line, Aaron Burns, Sean Butler, Jerry Cashbolm, Craig J Forsyth
Salvinorin A (1) is natural product that in humans is a hallucinogen which binds the human κ-opioid receptor. A total synthesis has been developed that parlays L-(+)-tartaric acid into that of (-)-1 via an unprecedented allylic dithiane intramolecular Diels-Alder reaction to obtain the trans-decalin scaffold. Tsuji allylation set the C9 quaternary center and a late-stage stereoselective chiral ligand-assisted addition of a 3-titanium furan upon a C12 aldehyde / C17 methyl ester established the furanyl lactone moiety...
October 18, 2016: Chemistry: a European Journal
Gao-Feng Bian, Yun Guo, Xiao-Jing Lv, Cheng Zhang
The preparation and the photophysical behaviour of two benzoxazinone derivatives isomers 2-(1-hydroxynaphthalen-2-yl)-4H-benzo[e][1, 3]oxazin-4-one(1) and 2-(3-hydroxynaphthalen-2-yl)-4H-benzo[e][1, 3]oxazin-4-one(2) designed for displaying were reported. The effect of substituent position and solvent effect on the excited state intramolecular proton transfer (ESIPT) dynamics and the spectroscopic properties were investigated using a combined theoretical (i.e., time-dependent density function theory (DFT)) and experimental (i...
October 18, 2016: Journal of Fluorescence
Carlo Barnaba, Maria Teresa Rodríguez-Estrada, Giovanni Lercker, Hugo Sergio García, Ilce Gabriela Medina-Meza
In this work we studied the effect of polyunsaturated fatty acids (PUFAs) methyl esters on cholesterol photo-induced oxidation. The oxidative routes were modeled with a chemical reaction network (CRN), which represents the first application of CRN to the oxidative degradation of a food-related lipid matrix. Docosahexaenoic acid (DHA, T-I), eicosapentaenoic acid (EPA, T-II) and a mixture of both (T-III) were added to cholesterol using hematoporphyrin as sensitizer, and were exposed to a fluorescent lamp for 48h...
October 15, 2016: Steroids
K Bridget Brosnihan, Victor M Pulgar, Manish S Bharadwaj, Liomar A A Neves, Liliya M Yamaleyeva
BACKGROUND: Cyclooxygenase (COX)-derived prostanoids (PGE2, PGI2) are important contributors to the process of decidualization. Previous studies showed the presence of Ang-(1-7) in the primary and secondary decidualized zones of the implantation site at early pregnancy. Decreased concentrations of Ang-(1-7) were found in the decidualized uterus compared to the non-decidualized uterus of pseudopregnant rats, suggesting that low levels of Ang-(1-7) are required for successful decidualization at early pregnancy...
October 18, 2016: Reproductive Biology and Endocrinology: RB&E
Elisabeth Varga, Gerlinde Wiesenberger, Philipp Fruhmann, Alexandra Malachová, Thomas Svoboda, Marc Lemmens, Gerhard Adam, Franz Berthiller
Trichothecenes are a class of structurally diverse mycotoxins with more than 200 naturally occurring compounds. Previously, a new compound, pentahydroxyscirpene (PHS), was reported as a byproduct of a nivalenol producing Fusarium strain, IFA189. PHS contains a hydroxy group at C-8 instead of the keto group of type B trichothecenes. In this work, we demonstrate that IFA189 belongs to the species Fusarium kyushuense using molecular tools. Production of PHS in vitro was also observed for several isolates of other Fusarium species producing nivalenol...
October 14, 2016: Toxins
Xiaohong Zhou, Yuren Jiang, Xiongjie Zhao, Dong Guo
Photoactivatable fluorophores have become an important technique for the high spatiotemporal resolution of biological imaging. Here, we developed a novel photoactivatable probe (PHBT), which is based on 2-(2-hydroxyphenyl)benzothiazole (HBT), a small organic fluorophore known for its classic luminescence mechanism through excited-state intramolecular proton transfer (ESIPT) with the keto form and the enol form. After photocleavage, PHBT released a ratiometric fluorophore HBT, which showed dual emission bands with more than 73-fold fluorescence enhancement at 512 nm in buffer and more than 69-fold enhancement at 452 nm in bovine serum...
October 12, 2016: Sensors
Mariana Angoa-Pérez, John H Anneken, Donald M Kuhn
The present review briefly explores the neurotoxic properties of methcathinone, mephedrone, methylone, and methylenedioxypyrovalerone (MDPV), four synthetic cathinones most commonly found in "bath salts." Cathinones are β-keto analogs of the commonly abused amphetamines and display pharmacological effects resembling cocaine and amphetamines, but despite their commonalities in chemical structures, synthetic cathinones possess distinct neuropharmacological profiles and produce unique effects. Among the similarities of synthetic cathinones with their non-keto analogs are their targeting of monoamine systems, the release of neurotransmitters, and their stimulant properties...
October 18, 2016: Current Topics in Behavioral Neurosciences
Sophie Front, Anna Biela-Banaś, Patricie Burda, Diana Ballhausen, Katsumi Higaki, Anna Caciotti, Amelia Morrone, Julie Charollais-Thoenig, Estelle Gallienne, Stéphane Demotz, Olivier R Martin
This report is about the identification, synthesis and initial biological characterization of derivatives of 4-epi-isofagomine as pharmacological chaperones (PC) for human lysosomal β-galactosidase. The two epimers of 4-epi-isofagomine carrying a pentyl group at C-5a, namely (5aR)- and (5aS)-5a-C-pentyl-4-epi-isofagomine, were prepared by an innovative procedure involving in the key step the addition of nitrohexane to a keto-pentopyranoside. Both epimers were evaluated as inhibitors of the human β-galactosidase: the (5aR)-stereoisomer (compound 1) was found to be a very potent inhibitor of the enzyme (IC50 = 8 nM, 30× more potent than 4-epi-isofagomine at pH 7...
September 29, 2016: European Journal of Medicinal Chemistry
Salette Martinez, Robert P Hausinger
The ethylene-forming enzyme (EFE) from Pseudomonas syringae pv. phaseolicola PK2 is a member of the mononuclear non-heme Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenase superfamily. This enzyme is reported to simultaneously catalyze the conversion of 2OG into ethylene plus three CO2 and the Cδ hydroxylation of L-arginine (L-Arg) while oxidatively decarboxylating 2OG to form succinate and carbon dioxide. A new plasmid construct for expression in recombinant Escherichia coli cells allowed for the purification of large amounts of EFE with greater activity than previously recorded...
October 17, 2016: Biochemistry
Michael Vogt, Christian Brüsseler, Jan van Ooyen, Michael Bott, Jan Marienhagen
The pentanol isomers 2-methyl-1-butanol and 3-methyl-1-butanol represent commercially interesting alcohols due to their potential application as biofuels. For a sustainable microbial production of these compounds, Corynebacterium glutamicum was engineered for producing 2-methyl-1-butanol and 3-methyl-1-butanol via the Ehrlich pathway from 2-keto-3-methylvalerate and 2-ketoisocaproate, respectively. In addition to an already available 2-ketoisocaproate producer, a 2-keto-3-methylvalerate accumulating C. glutamicum strain was also constructed...
October 13, 2016: Metabolic Engineering
Alexander J Frey, Qingqing Wang, Christine Busch, Daniel Feldman, Lisa Bottalico, Clementina A Mesaros, Ian A Blair, Anil Vachani, Nathaniel W Snyder
A multiplexed quantitative method for the analysis of three major unconjugated steroids in human serum by stable isotope dilution liquid chromatography-high resolution mass spectrometry (LC-HRMS) was developed and validated on a Q Exactive Plus hybrid quadrupole/Orbitrap mass spectrometer. This quantification utilized isotope dilution and Girard P derivatization on the keto-groups of testosterone (T), androstenedione (AD) and dehydroepiandrosterone (DHEA) to improve ionization efficiency using electrospray ionization...
October 13, 2016: Steroids
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