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https://www.readbyqxmd.com/read/28221047/excited-state-proton-transfer-in-indigo
#1
Joao Pina, Daniela Santos Sarmento, Marco Accoto, Pier Luigi Gentili, Luigi Vaccaro, Adelino M Galvão, J Sérgio Seixas de Melo
Excited state proton transfer (ESPT) in Indigo (Ind) and its mono hexyl-substituted derivative (NHxInd) in solution was investigated experimentally as a function of solvent viscosity, polarity and temperature, and theoretically by time-dependent DFT (TDDFT) calculations. Although a single emission band is observed, the fluorescence decays (collected at different wavelengths along the emission band using time-correlated single photon counting (TCSPC)) are bi-exponential, with two identical decay times but different pre-exponential factors, consistent with the existence of excited state keto and enol species...
February 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28216576/identification-of-2-keto-3-deoxy-d-gluconate-kinase-and-2-keto-3-deoxy-d-phosphogluconate-aldolase-in-an-alginate-assimilating-bacterium-flavobacterium-sp-strain-umi-01
#2
Ryuji Nishiyama, Akira Inoue, Takao Ojima
Recently, we identified an alginate-assimilating gene cluster in the genome of Flavobacterium sp. strain UMI-01, a member of Bacteroidetes. Alginate lyase genes and a 4-deoxy-l-erythro-5-hexoseulose uronic acid (DEH) reductase gene in the cluster have already been characterized; however, 2-keto-3-deoxy-d-gluconate (KDG) kinase and 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase genes, i.e., flkin and flald, still remained uncharacterized. The amino acid sequences deduced from flkin and flald showed low identities with those of corresponding enzymes of Saccharophagus degradans 2-40(T), a member of Proteobacteria (Kim et al...
February 14, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28196134/alterations-in-estrogen-signalling-pathways-upon-acquisition-of-anthracycline-resistance-in-breast-tumor-cells
#3
Simon Chewchuk, Baoqing Guo, Amadeo Mark Parissenti
Intrinsic or acquired drug resistance is a major impediment to the successful treatment of women with breast cancer using chemotherapy. We have observed that MCF-7 breast tumor cells selected for resistance to doxorubicin or epirubicin (MCF-7DOX2 and MCF-7EPI cells, respectively) exhibited increased expression of several members of the aldo-keto reductase (AKR) gene family (in particular AKR1C3 and AKR1B10) relative to control MCF-7CC cells selected by propagation in the absence of drug. Normal cellular roles for the AKRs include the promotion of estrogen (E2) synthesis from estrone (E1) and the hydroxylation and detoxification of exogenous xenobiotics such as anthracycline chemotherapy drugs...
2017: PloS One
https://www.readbyqxmd.com/read/28181382/selected-mutations-reveal-new-intermediates-in-the-biosynthesis-of-mupirocin-and-the-thiomarinol-antibiotics
#4
Shu-Shan Gao, Luoyi Wang, Zhongshu Song, Joanne Hothersall, Elton R Stevens, Jack Connolly, Peter J Winn, Russell J Cox, Matthew P Crump, Paul R Race, Christopher M Thomas, Thomas J Simpson, Christine L Willis
Thiomarinol and mupirocin are assembled on similar polyketide/fatty acid backbones and exhibit potent antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA). They both contain a tetrasubstituted tetrahydropyran (THP) ring that is essential for biological activity. Mupirocin is a mixture of pseudomonic acids (PAs). Isolation of the novel compound mupirocin P, which contains a 7-hydroxy-6-keto-substituted THP, from a ΔmupP strain and chemical complementation experiments confirm that the first step in the conversion of PA-B into the major product PA-A is oxidation at the C6 position...
February 9, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28163064/thermal-stability-of-plant-sterols-and-formation-of-their-oxidation-products-in-vegetable-oils-and-margarines-upon-controlled-heating
#5
Yuguang Lin, Diny Knol, Iris Valk, Vincent van Andel, Silvia Friedrichs, Dieter Lütjohann, Karel Hrncirik, Elke A Trautwein
Fat-based products like vegetable oils and margarines are commonly used for cooking, which may enhance oxidation of plant sterols (PS) present therein, leading to the formation of PS oxidation products (POP). The present study aims to assess the kinetics of POP formation in six different fat-based products. Vegetable oils and margarines without and with added PS (7.5-7.6% w/w) in esterified form were heated in a Petri-dish at temperatures of 150, 180 and 210°C for 8, 12 and 16min. PS and POP were analysed using GC-FID and GC-MS-SIM, respectively...
February 2, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28161411/structural-basis-for-the-inhibition-of-akr1b10-by-the-c3-brominated-ttnpb-derivative-uvi2008
#6
Francesc X Ruiz, Isidro Crespo, Susana Álvarez, Sergio Porté, Joan Giménez-Dejoz, Alexandra Cousido-Siah, André Mitschler, Ángel R de Lera, Xavier Parés, Alberto Podjarny, Jaume Farrés
UVI2008, a retinoic acid receptor (RAR) β/γ agonist originated from C3 bromine addition to the parent RAR pan-agonist 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (TTNPB), is also a selective inhibitor of aldo-keto reductase family member 1B10 (AKR1B10). Thus, it might become a lead drug for the design of compounds targeting both activities, as an AKR1B10 inhibitor and RAR agonist, which could constitute a novel therapeutic approach against cancer and skin-related diseases...
February 1, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28149959/synthesis-of-hetero-bifunctional-end-capped-oligo-edot-derivatives
#7
Christopher D Spicer, Marsilea A Booth, Damia Mawad, Astrid Armgarth, Christian B Nielsen, Molly M Stevens
Conjugated oligomers of 3,4-ethylenedioxythiophene (EDOT) are attractive materials for tissue engineering applications and as model systems for studying the properties of the widely used polymer poly(3,4-ethylenedioxythiophene). We report here the facile synthesis of a series of keto-acid end-capped oligo-EDOT derivatives (n = 2-7) through a combination of a glyoxylation end-capping strategy and iterative direct arylation chain extension. Importantly, these structures not only represent the longest oligo-EDOTs reported but are also bench stable, in contrast to previous reports on such oligomers...
January 12, 2017: Chem
https://www.readbyqxmd.com/read/28120966/hydration-of-the-simplest-%C3%AE-keto-acid-a-rotational-spectroscopic-and-ab-initio-study-of-the-pyruvic-acid-water-complex
#8
Elijah G Schnitzler, Nathan A Seifert, Supriya Ghosh, Javix Thomas, Yunjie Xu, Wolfgang Jäger
Intermolecular interactions between pyruvic acid, the simplest α-keto acid, and water are important in bio- and atmospheric chemistry. In this context, the pure rotational spectrum of the pyruvic acid-water complex was measured from 7 to 15 GHz using a cavity-based Fourier-transform microwave spectrometer. In the detected isomer, water acts as a hydrogen bond donor and acceptor, bridging the acidic hydrogen and the keto oxygen. Both a- and b-type transitions were observed; however, c-type transitions were not observed, due to vibrational averaging of the effectively barrier-less wagging motion of the free hydrogen of the water subunit, which results in an effective ground state structure with a plane of symmetry...
January 25, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28111842/detoxification-of-benzo-a-pyrene-primarily-depends-on-cytochrome-p450-while-bioactivation-involves-additional-oxidoreductases-including-5-lipoxygenase-cyclooxygenase-and-aldo-keto-reductase-in-the-liver
#9
Liupeng Wang, Wenwei Xu, Leilei Ma, Suxing Zhang, Kezhi Zhang, Peizhen Ye, Guozhen Xing, Xuefeng Zhang, Yiyi Cao, Jing Xi, Jun Gu, Yang Luan
Cytochrome P450s are involved in detoxification and activation of benzo[a]pyrene (BaP) with unclear balance and unknown contribution of other oxidoreductases. Here, we investigated the BaP and BaP-induced mutagenicity in hepatic and extra-hepatic tissues using hepatic P450 reductase null (HRN) gpt mice. After 2-week treatment (50 mg/kg, i.p. 4 days), BaP in the liver and lung of HRN-gpt mice were increased. BaP promoted gpt mutant frequency (MF) in HRN-gpt mice liver. MF of gpt in the lung and Pig-a in hematopoietic cells induced by BaP in HRN-gpt mice were increased than in gpt mice...
January 23, 2017: Journal of Biochemical and Molecular Toxicology
https://www.readbyqxmd.com/read/28110820/synthesis-of-new-analogs-of-akba-and-evaluation-of-their-anti-inflammatory-activities
#10
Bharani Meka, Suryachandra Rao Ravada, Muthyala Murali Krishna Kumar, Kurre Purna Nagasree, Trimurtulu Golakoti
A new series of 11-keto-β-boswellic acid and 3-O-acetyl-11-keto-β-boswellic acid analogs (5, 7, 8, 10, 13, 18a-d, 27a-c, 28a-d) were synthesized by modification of hydroxyl and acid functional moieties of boswellic acids. The structures of these analogs were confirmed by spectral data analysis ((1)H, (13)C NMR and mass). Compounds 18b, 27a and 8 showed potent 5-lipoxygenase enzyme inhibitory activity (IC50: 19.53, 20.31 and 44.14μg/mL). The computational studies revealed that selectivity of AKBA is due to its fitment into the 5-LOX receptor, which is missing for the other enzymes like 12-LOX, COX-1 and COX-2...
December 29, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28096310/characterization-of-the-dtdp-fuc3n-and-dtdp-qui3n-biosynthetic-pathways-in-campylobacter-jejuni-81116%C3%A2
#11
Zack Z Li, Alexander S Riegert, Marie-France Goneau, Anna M Cunningham, Evgeny Vinogradov, Jianjun Li, Ian C Schoenhofen, James B Thoden, Hazel M Holden, Michel Gilbert
The Gram-negative bacterium Campylobacter jejuni 81116 (Penner serotype HS:6) has a class E lipooligosaccharide (LOS) biosynthesis locus containing 19 genes, which encode for 11 putative glycosyltransferases, 1 lipid A acyltransferase and 7 enzymes thought to be involved in the biosynthesis of dideoxyhexosamine (ddHexN) moieties. Although the LOS outer core structure of C. jejuni 81116 is still unknown, recent mass spectrometry analyses suggest that it contains acetylated forms of two ddHexN residues. For this investigation, five of the genes encoding enzymes reportedly involved in the biosyntheses of these sugar residues were examined, rmlA, rmlB, wlaRA, wlaRB and wlaRG Specifically, these genes were cloned and expressed in Escherichia coli, and the corresponding enzymes were purified and tested for biochemical activity...
January 16, 2017: Glycobiology
https://www.readbyqxmd.com/read/28067100/effects-of-a-single-bout-of-strenuous-exercise-on-platelet-activation-in-female-apoe-ldlr-mice
#12
K Przyborowski, H Kassassir, M Wojewoda, K Kmiecik, B Sitek, K Siewiera, A Zakrzewska, A M Rudolf, R Kostogrys, C Watala, J A Zoladz, S Chlopicki
Strenuous physical exercise leads to platelet activation that is normally counterbalanced by the production of endothelium-derived anti-platelet mediators, including prostacyclin (PGI2) and nitric oxide (NO). However, in the case of endothelial dysfunction, e.g. in atherosclerosis, there exists an increased risk for intravascular thrombosis during exercise that might be due to an impairment in endothelial anti-platelet mechanisms. In the present work, we evaluated platelet activation at rest and following a single bout of strenuous treadmill exercise in female ApoE/LDLR(-)(/-) mice with early (3-month-old) and advanced (7-month-old) atherosclerosis compared to female age-matched WT mice...
January 9, 2017: Platelets
https://www.readbyqxmd.com/read/28007565/mechanism-of-degradation-of-an-%C3%AE-keto-epoxide-a-model-for-the-warhead-for-various-proteasome-inhibitor-anticancer-agents
#13
Kirsten M Phizackerley, Mouhannad Jumaa, Antonio Lopalco, Bradley H Wolfe, Christopher D Ablan, Valentino J Stella
The anti-cancer agent, carfilzomib has a unique α-keto-epoxide warhead. The model α-keto-epoxide, N-((S)-1-((R)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)pivalamide (1) along with a few of its degradation products were synthesized and studied. The kinetics of hydrolysis and identification of some of the degradation products of 1 were performed at pH values 2, 4, 5, 7 and 8 at 25°C, 40°C and 60°C and followed by HPLC and LC-MS, respectively. 1 degraded independent of pH between pH values 4 to 7 but showed some acid catalysis at pH 2 and base catalysis at pH 8...
December 19, 2016: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28003063/increased-potential-for-wound-activated-production-of-prostaglandin-e2-and-related-toxic-compounds-in-non-native-populations-of-gracilaria-vermiculophylla
#14
Mareike Hammann, Martin Rempt, Georg Pohnert, Gaoge Wang, Sung Min Boo, Florian Weinberger
The capacity of the East Asian seaweed Gracilaria vermiculophylla ("Ogonori") for production of prostaglandin E2 from arachidonic acid occasionally causes food poisoning after ingestion. During the last two decades the alga has been introduced to Europe and North America. Non-native populations have been shown to be generally less palatable to marine herbivores than native populations. We hypothesized that the difference in palatability among populations could be due to differences in the algal content of prostaglandins...
January 2016: Harmful Algae
https://www.readbyqxmd.com/read/27986991/recombinant-expression-and-characterization-of-a-l-amino-acid-oxidase-from-the-fungus-rhizoctonia-solani
#15
Katharina Hahn, Katrin Neumeister, Andreas Mix, Tilman Kottke, Harald Gröger, Gabriele Fischer von Mollard
L-Amino acid oxidases (L-AAOs) catalyze the oxidative deamination of L-amino acids to the corresponding α-keto acids, ammonia, and hydrogen peroxide. L-AAOs are homodimeric enzymes with FAD as a non-covalently bound cofactor. They are of potential interest for biotechnological applications. However, heterologous expression has not succeeded in producing large quantities of active recombinant L-AAOs with a broad substrate spectrum so far. Here, we report the heterologous expression of an active L-AAO from the fungus Rhizoctonia solani in Escherichia coli as a fusion protein with maltose-binding protein (MBP) as a solubility tag...
December 16, 2016: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/27980494/in-vivo-osteoinduction-evaluating-2-beta-coxatene-as-an-immunoinductive-compound-and-novel-ingredient-for-joint-support
#16
Katherine Spinks, James J Scaffidi
CONTEXT: Osteoarthritis (OA) is a degenerative joint disease characterized by progressive loss of articular cartilage. Many treatments lack the ability to stimulate the growth of native cartilage tissue while they simultaneously increase joint comfort. For the past few decades, dietary supplements have been investigated for the ability to both address joint inflammation and stimulate cartilage tissue. OBJECTIVES: The present study intended to examine the supplement's in vivo osteoinductive capabilities and clinical efficacy for overall joint health...
October 2016: Integrative Medicine
https://www.readbyqxmd.com/read/27979258/carotenoids-and-carotenoid-esters-of-orange-and-yellow-fleshed-mamey-sapote-pouteria-sapota-jacq-h-e-moore-stearn-fruit-and-their-post-prandial-absorption-in-humans
#17
Tania Chacón-Ordóñez, Ralf M Schweiggert, Anja Bosy-Westphal, Víctor M Jiménez, Reinhold Carle, Patricia Esquivel
Although different genotypes of mamey sapote with distinct pulp colors are consumed in countries from Central to South America, in-depth knowledge on genotype-related differences of their carotenoid profile is lacking. Since the fruit was found to contain the potentially vitamin A-active keto-carotenoids sapotexanthin and cryptocapsin, we sought to qualitatively and quantitatively describe the carotenoid profile of different genotypes by HPLC-DAD-MS(n). Sapotexanthin and cryptocapsin were present in all genotypes...
April 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/27951728/effects-of-astaxanthin-on-blood-coagulation-fibrinolysis-and-platelet-aggregation-in-hyperlipidemic-rats
#18
Zu-Yue Deng, Wei-Guang Shan, Shen-Feng Wang, Meng-Mei Hu, Yan Chen
CONTEXT: Astaxanthin (ASTX) is a xanthophyll carotenoid that reduces hemostasis in hyperlipidemic organisms. Its antihemostatic mechanisms remain unclear. OBJECTIVE: The effects of ASTX on coagulation, the fibrinolytic system and platelet aggregation were investigated in hyperlipidemic rats. MATERIALS AND METHODS: Different doses of ASTX (5, 10 and 30 mg/kg/day, p.o.) were administered for four weeks to high-fat diet-induced hyperlipidemic rats...
December 2017: Pharmaceutical Biology
https://www.readbyqxmd.com/read/27940118/screening-of-luzula-species-native-to-the-carpathian-basin-for-anti-inflammatory-activity-and-bioactivity-guided-isolation-of-compounds-from-luzula-luzuloides-lam-dandy-wilmott
#19
Barbara Tóth, Fang-Rong Chang, Tsong-Long Hwang, Ádám Szappanos, Attila Mándi, Attila Hunyadi, Tibor Kurtán, Gusztáv Jakab, Judit Hohmann, Andrea Vasas
The present study focused on the anti-inflammatory screening of Luzula species native to the Carpathian Basin and bioactivity-guided isolation of compounds of Luzula luzuloides (Lam.) Dandy & Wilmott. The anti-inflammatory properties of extracts with different polarity prepared from Luzula species were determined. Among them, the CH2Cl2-soluble fraction of L. luzuloides possessed strong inhibitory effects on superoxide anion generation (99.39±0.37%) and elastase release (114.22±3.13%) in fMLP/CB-induced human neutrophils at concentration of 10μg/mL...
January 2017: Fitoterapia
https://www.readbyqxmd.com/read/27935701/cobalt-catalyzed-6-2-cycloaddition-of-alkynes-with-1-3-5-7-cyclooctatetraene-as-a-key-element-in-the-direct-construction-of-substituted-bicyclo-4-3-1-decanes
#20
Vladimir A D'yakonov, Gulnara N Kadikova, Lilya U Dzhemileva, Guzel F Gazizullina, Ilfir R Ramazanov, Usein M Dzhemilev
A new, effective catalytic system based on Co(acac)2 has been developed for [6 + 2] cycloaddition of terminal alkynes to 1,3,5,7-cyclooctatetraene to give substituted bicyclo[4.2.2]deca-2,4,7,9-tetraenes in high yields (68-85%). The electrophilic activation of double bonds in the bicyclic products with m-CPBA is an efficient method for the synthesis of substituted bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols, which form the key structural moieties of numerous natural biologically active compounds. The structures of the obtained compounds were reliably proven by modern spectral methods and X-ray diffraction...
December 20, 2016: Journal of Organic Chemistry
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