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https://www.readbyqxmd.com/read/27911794/activation-of-mutant-tert-promoter-by-ras-erk-signaling-is-a-key-step-in-malignant-progression-of-braf-mutant-human-melanomas
#1
Yinghui Li, Hui Shan Cheng, Wee Joo Chng, Vinay Tergaonkar
Although activating BRAF/NRAS mutations are frequently seen in melanomas, they are not sufficient to drive malignant transformation and require additional events. Frequent co-occurrence of mutations in the promoter for telomerase reverse transcriptase (TERT), along with BRAF alterations, has recently been noted and correlated with poorer prognosis, implicating a functional link between BRAF signaling and telomerase reactivation in melanomas. Here, we report that RAS-ERK signaling in BRAF mutant melanomas is critical for regulating active chromatin state and recruitment of RNA polymerase II at mutant TERT promoters...
November 23, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27911386/a-protocol-for-safe-lithiation-reactions-using-organolithium-reagents
#2
Michael R Gau, Michael J Zdilla
Organolithium reagents are powerful tools in the synthetic chemist's toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented...
November 12, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27910182/catalyst-free-polyhydroboration-of-dodecaborate-yields-highly-photoluminescent-ionic-polyarylated-clusters
#3
Mark W Lee
The incorporation of polyhedral boranes into novel photoluminescent materials is an area with increasing interest. While the neutral carboranes have been widely investigated for this purpose, the dodecaborate ion has received much less attention. Herein we report a significant expansion to the scope of substitution reactions for the dodecaborate ion, whereby this cluster was observed to react directly with a wide range of arenes in a step-wise and controlled manner. In the products of these reactions, the dodecaborate ion serves as a core upon which up to nine mono- or polycyclic aromatic hydrocarbon ligands are exohedrally bonded...
December 2, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27909346/copper-i-dioxygen-adducts-and-copper-enzyme-mechanisms
#4
Jeffrey J Liu, Daniel E Diaz, David A Quist, Kenneth D Karlin
Primary copper(I)-dioxygen (O2) adducts, cupric-superoxide complexes, have been proposed intermediates in copper-containing dioxygen-activating monooxygenase and oxidase enzymes. Here, mechanisms of C-H activation by reactive copper-(di)oxygen intermediates are discussed, with an emphasis on cupric-superoxide species. Over the past 25 years, many synthetically derived cupric-superoxide model complexes have been reported. Due to the thermal instability of these intermediates, early studies focused on increasing their stability and obtaining physical characterization...
October 2016: Israel Journal of Chemistry
https://www.readbyqxmd.com/read/27908234/sustained-early-disruption-of-mitochondrial-function-contributes-to-arsenic-induced-prostate-tumorigenesis
#5
B Singh, M Kulawiec, K M Owens, A Singh, K K Singh
Arsenic is a well-known human carcinogen that affects millions of people worldwide, but the underlying mechanisms of carcinogenesis are unclear. Several epidemiological studies have suggested increased prostate cancer incidence and mortality due to exposure to arsenic. Due to lack of an animal model of arsenic-induced carcinogenesis, we used a prostate epithelial cell culture model to identify a role for mitochondria in arsenic-induced prostate cancer. Mitochondrial morphology and membrane potential was impacted within a few hours of arsenic exposure of non-neoplastic prostate epithelial cells...
October 2016: Biochemistry. Biokhimii︠a︡
https://www.readbyqxmd.com/read/27906994/enhancing-hiv-testing-and-treatment-among-men-who-have-sex-with-men-in-china-a-pilot-model-with-two-rapid-tests-single-blood-draw-session-and-intensified-case-management-in-six-cities-in-2013
#6
Dapeng Zhang, Hongyan Lu, Minghua Zhuang, Guohui Wu, Hongjing Yan, Jun Xu, Xiaoli Wei, Chengmei Li, Sining Meng, Xiaojing Fu, Jinlei Qi, Peng Wang, Mei Luo, Min Dai, Ray Yip, Jiangping Sun, Zunyou Wu
OBJECTIVES: To explore models to improve HIV testing, linkage to care and treatment among men who have sex with men (MSM) in cooperation with community-based organizations (CBOs) in China. METHODS: We introduced a new model for HIV testing services targeting MSM in six cities in 2013.These models introduced provision of rapid HIV testing by CBO staff and streamlined processes for HIV screening, confirmation of initial reactive screening results, and linkage to care among diagnosed people...
2016: PloS One
https://www.readbyqxmd.com/read/27905156/kinetics-of-the-competitive-reactions-of-isomerization-and-peptide-bond-cleavage-at-l-%C3%AE-and-d-%C3%AE-aspartyl-residues-in-an-%C3%AE-a-crystallin-fragment
#7
Kenzo Aki, Emiko Okamura
d-β-aspartyl (Asp) residue has been found in a living body such as aged lens crystallin, although l-α-amino acids are constituents in natural proteins. Isomerization from l-α- to d-β-Asp probably modulates structures to affect biochemical reactions. At Asp residue, isomerization and peptide bond cleavage compete with each other. To gain insight into how fast each reaction proceeds, the analysis requires the consideration of both pathways simultaneously and independently. No information has been provided, however, about these competitive processes because each reaction has been studied separately...
December 1, 2016: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/27904671/melatonin-promotes-diabetic-wound-healing-in-vitro-by-regulating-keratinocyte-activity
#8
Ruipeng Song, Lijun Ren, Haoli Ma, Ruijing Hu, Honghong Gao, Li Wang, Xuehui Chen, Zhigang Zhao, Jialin Liu
Diabetic patients are at high risk of developing delayed cutaneous wound healing. Proper keratinocyte proliferation and migration are crucial steps during re-epithelialization. Melatonin (Mel) accelerates wound repair in full-thickness incisional wounds; however, its role in diabetic wound healing is unknown. This study explored the role of Mel in diabetic wound healing in vitro by using high glucose (HG)-cultured keratinocytes. Mel reduced the HG-induced mRNA expression and release of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-8, in keratinocytes...
2016: American Journal of Translational Research
https://www.readbyqxmd.com/read/27904520/a-diagnostic-one-step-real-time-reverse-transcription-polymerase-chain-reaction-method-for-accurate-detection-of-influenza-virus-type-a
#9
Mohammad Amin Behzadi, Mazyar Ziyaeyan, Abdolvahab Alborzi
INTRODUCTION: Influenza A is known as a public health concern worldwide. In this study, a novel one-step real-time reverse transcription polymerase chain reaction (rtRT-PCR) assay was designed and optimized for the detection of influenza A viruses. MATERIAL AND METHODS: The primers and probe were designed based on the analysis of 90 matrix nucleotide sequence data of influenza type A subtypes from the GenBank database of the National Center for Biotechnology Information (NCBI)...
December 1, 2016: Archives of Medical Science: AMS
https://www.readbyqxmd.com/read/27904095/synthesis-of-effective-food-constituents-toward-the-development-of-chemical-biology-investigations
#10
Tomohiro Asakawa
 This article describes the development of various probes and immunogens for chemical-biological investigations of food flavonoids. We accomplished a large (gram)-scale asymmetric synthesis of a key intermediate, 5-aminopentyl deoxy epigallocatechin-3-gallate (APDOEGCg; 3), an analogue of green tea polyphenol EGCg, in which the key step was cationic cyclization utilizing neighboring group participation of the gallate carbonyl group. The synthetic APDOEGCg (3) was efficiently converted to a fluorescent probe 18 and an immunogen 19 by utilizing the high reactivity of the amine functional group...
2016: Yakugaku Zasshi: Journal of the Pharmaceutical Society of Japan
https://www.readbyqxmd.com/read/27903582/threshold-levels-of-extracellular-l-arginine-that-trigger-nos-mediated-ros-rns-production-in-cardiac-ventricular-myocytes
#11
Jayalakshmi Ramachandran, R Daniel Peluffo
L-arginine (L-Arg) is the substrate for nitric oxide synthase (NOS) to produce nitric oxide (NO), a signaling molecule that is key in cardiovascular physiology and pathology. In cardiac myocytes, L-Arg is incorporated from the circulation through the functioning of system-y(+) cationic amino acid transporters. Depletion of L-Arg leads to NOS uncoupling, with O2 rather than L-Arg as terminal electron acceptor, resulting in superoxide formation. The reactive oxygen species (ROS) superoxide (O2•(-)), combined with NO, may lead to the production of the reactive nitrogen species (RNS) peroxynitrite (ONOO-), which is recognized as a major contributor to myocardial depression...
November 30, 2016: American Journal of Physiology. Cell Physiology
https://www.readbyqxmd.com/read/27899288/one-step-reverse-transcription-loop-mediated-isothermal-amplification-for-the-detection-of-maize-chlorotic-mottle-virus-in-maize
#12
Ling Chen, Zhiyuan Jiao, Dongmei Liu, Xingliang Liu, Zihao Xia, Congliang Deng, Tao Zhou, Zaifeng Fan
Maize chlorotic mottle virus (MCMV) is spreading in many regions worldwide, causing maize lethal necrosis when co-infected with a potyvirid. In this study, one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to detect MCMV in maize. A set of four specific primers was designed based on the conserved coat protein gene sequences of MCMV. The RT-LAMP could be completed within 60min under isothermal condition at 63°C. The sensitivity test showed that the RT-LAMP was about 10-fold more sensitive than RT-PCR and no cross-reactivity was detected with other viral pathogens infecting maize in China...
November 26, 2016: Journal of Virological Methods
https://www.readbyqxmd.com/read/27896955/adsorption-and-reactive-desorption-on-metal-organic-frameworks-a-direct-strategy-for-lactic-acid-recovery
#13
Timothée Stassin, Helge Reinsch, Ben Van de Voorde, Stefan Wuttke, Dana D Medina, Norbert Stock, Thomas Bein, Rob Ameloot, Dirk De Vos
Biomass-derived lactic acid (LA) is an important platform chemical towards the sustainable production of numerous materials. However, the fermentation process currently in use is limited by the difficult recovery of the LA product from the fermentation broth and results in the generation of stoichiometric amounts of gypsum waste. Herein, we show that metal-organic frameworks (MOFs) of the UiO-66(Zr) type are effective adsorbents for the separation of LA from aqueous (buffer) solutions. These frameworks based on zirconium clusters and terephthalic acid derivatives display a tremendous uptake (up to 42 wt %) and a high affinity for LA...
November 29, 2016: ChemSusChem
https://www.readbyqxmd.com/read/27896865/sensing-at-the-surface-of-graphene-field-effect-transistors
#14
Wangyang Fu, Lin Jiang, Erik P van Geest, Lia M C Lima, Grégory F Schneider
Recent research trends now offer new opportunities for developing the next generations of label-free biochemical sensors using graphene and other two-dimensional materials. While the physics of graphene transistors operated in electrolyte is well grounded, important chemical challenges still remain to be addressed, namely the impact of the chemical functionalizations of graphene on the key electrical parameters and the sensing performances. In fact, graphene - at least ideal graphene - is highly chemically inert...
November 29, 2016: Advanced Materials
https://www.readbyqxmd.com/read/27896797/a-telephone-based-intervention-to-promote-physical-activity-during-smoking-cessation-a-randomized-controlled-proof-of-concept-study
#15
Uma S Nair, Freda Patterson, Daniel Rodriguez, Bradley N Collins
Smoking and physical inactivity contribute to disproportionate disease burden among underserved adults. Telephone-based interventions (quitlines) are becoming the standard care for addressing smoking. There is increasing interest to determine whether quitlines can be utilized to administer interventions for other unhealthy behaviors. This study aims to examine the proof-of-concept and potential efficacy of a telephone-based behavioral counseling intervention to boost daily low-to-moderate physical activity among low-income, physically inactive smokers...
November 28, 2016: Translational Behavioral Medicine
https://www.readbyqxmd.com/read/27896346/visible-light-driven-mesoporous-ag-embedded-zno-nanocomposites-reactive-oxygen-species-enhanced-photocatalysis-bacterial-inhibition-and-photodynamic-therapy
#16
Jagriti Gupta, Jeotikanta Mohapatra, D Bahadur
We present here the multitasking capabilities of Ag-embedded ZnO nanocomposites (Ag-ZnO NCs), which include the photocatalytic degradation of organic dyes, bacterial inhibition, and cancer therapeutics. Ag-embedded ZnO nanocomposites (Ag-ZnO NCs) of mesoporous spherical morphology (size ∼ 150 ± 50 nm) are successfully synthesized by a facile and single step soft-chemical approach. To understand the effect of Ag loading on multitasking properties, Ag-ZnO NCs are synthesized with different wt% of Ag. It was found that Ag5-ZnO NCs (5 wt% of Ag) showed excellent solar light-induced photocatalytic degradation properties against both cationic as well as anionic dyes...
November 29, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27893783/role-of-pten-in-oxidative-stress-and-dna-damage-in-the-liver-of-whole-body-pten-haplodeficient-mice
#17
Ezgi Eyluel Bankoglu, Oliver Tschopp, Johannes Schmitt, Philipp Burkard, Daniel Jahn, Andreas Geier, Helga Stopper
Type 2 diabetes (T2DM) and obesity are frequently associated with non-alcoholic fatty liver disease (NAFLD) and with an elevated cancer incidence. The molecular mechanisms of carcinogenesis in this context are only partially understood. High blood insulin levels are typical in early T2DM and excessive insulin can cause elevated reactive oxygen species (ROS) production and genomic instability. ROS are important for various cellular functions in signaling and host defense. However, elevated ROS formation is thought to be involved in cancer induction...
2016: PloS One
https://www.readbyqxmd.com/read/27892585/elemental-steps-of-the-thermodynamics-of-dihydropyrimidine-a-new-class-of-organic-hydride-donors
#18
Fan-Kun Meng, Xiao-Qing Zhu
25 Dihydropyrimidine derivatives, a new class of organo-hydrides, were designed and synthesized by the Biginelli reaction. For the first time, the thermodynamic driving forces of the six elemental steps to obtain a hydride in acetonitrile were determined by isothermal titration and electrochemical methods, respectively. The effects of molecular structures and substituents on these thermodynamic parameters were examined, uncovering some interesting structure-reactivity relationships. Both the thermodynamic and kinetic studies show that the hydride transfer from dihydropyrimidines to 9-phenylxanthylium (PhXn(+)ClO4(-)) prefers a concerted mechanism...
November 28, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27892558/synthesis-and-reductive-elimination-of-arylpd-ii-trifluoromethyl-complexes-a-remarkable-concentration-effect-on-chemoselectivity
#19
Song-Lin Zhang, Zhu-Qin Deng
Reductive elimination from Pd(ii) aryl trifluoromethyl complexes is a challenging and elusive step which is accompanied by a number of kinetically more favorable side reactions giving rising to a complex mixture. We report herein the synthesis and isolation of several arylPd(ii) trifluoromethyl complexes (2a-c) and study their electronic structures, photophysical properties and reductive elimination reactivities. A remarkable concentration effect on chemoselectivity is observed for thermal decomposition of (Xantphos)Pd(ii)(Ar)(CF3) (2c) that favors the formation of Ar-CF3 at lower concentrations, but gives increasingly more Ar-Ar homocoupling product to a dominant extent as the concentration of 2c increases...
November 28, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27889801/production-and-purification-of-an-untagged-recombinant-pneumococcal-surface-protein-a-pspa4pro-with-high-purity-and-low-endotoxin-content
#20
Douglas B Figueiredo, Eneas Carvalho, Mauricio P Santos, Stefanie Kraschowetz, Rafaela T Zanardo, Gilson Campani, Gabriel G Silva, Cíntia R Sargo, Antonio Carlos L Horta, Roberto de C Giordano, Eliane N Miyaji, Teresa C Zangirolami, Joaquin Cabrera-Crespo, Viviane Maimoni Gonçalves
Streptococcus pneumoniae is the main cause of pneumonia, meningitis, and other conditions that kill thousands of children every year worldwide. The replacement of pneumococcal serotypes among the vaccinated population has evidenced the need for new vaccines with broader coverage and driven the research for protein-based vaccines. Pneumococcal surface protein A (PspA) protects S. pneumoniae from the bactericidal effect of human apolactoferrin and prevents complement deposition. Several studies indicate that PspA is a very promising target for novel vaccine formulations...
November 26, 2016: Applied Microbiology and Biotechnology
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