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https://www.readbyqxmd.com/read/29793040/quinones-and-nitroaromatic-compounds-as-subversive-substrates-of-staphylococcus-aureus-flavohemoglobin
#1
Myriam Moussaoui, Lina Misevičienė, Žilvinas Anusevičius, Audronė Marozienė, Florence Lederer, Laura Baciou, Narimantas Čėnas
In microorganisms, flavohemoglobins (FHbs) containing FAD and heme (Fe3+ , metHb) convert NO. into nitrate at the expense of NADH and O2 . FHbs contribute to bacterial resistance to nitrosative stress. Therefore, inhibition of FHbs functions may decrease the pathogen virulence. We report here a kinetic study of the reduction of quinones and nitroaromatic compounds by S. aureus FHb. We show that this enzyme rapidly reduces quinones and nitroaromatic compounds in a mixed single- and two-electron pathway. The reactivity of nitroaromatics increased upon an increase in their single-electron reduction potential (E1 7 ), whereas the reactivity of quinones poorly depended on their E1 7 with a strong preference for a 2-hydroxy-1,4-naphthoquinone structure...
May 21, 2018: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/29792679/a-nanozyme-and-ambient-light-based-smartphone-platform-for-simultaneous-detection-of-dual-biomarkers-from-exposure-to-organophosphorus-pesticides
#2
Yuting Zhao, Mingming Yang, Qiangqiang Fu, Hui Ouyang, Wei Wen, Yang Song, Chengzhou Zhu, Yuehe Lin, Dan Du
A transparent, lateral-flow test strip coupled with a smartphone-based ambient light sensor was first proposed for detect-ing enzymatic inhibition and phosphorylation. The principle of the platform is based on the simultaneous measurement of the total amount of the enzyme and enzyme activity to biomonitor exposure to organophosphorus (OP) pesticides. In this study, butyrylcholinesterase (BChE) was adopted as the model enzyme and ethyl paraoxon was chosen as an analyte representing OP pesticides. The total amount of BChE was quantified by a sensitive colorimetric signal originating from a sandwich immunochromatographic assay utilizing PtPd nanoparticles as a polyphenol oxidase-mimicking probe, which provided a higher sensitivity than that of a peroxidase-like probe...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792149/inhibition-of-mutated-isocitrate-dehydrogenase-1-in-cancer
#3
Fangrui Wu, Gang Cheng, Yuan Yao, Mari Kogiso, Hong Jiang, Xiao-Nan Li, Yongcheng Song
BACKGROUND: R132H mutation of isocitrate dehydrogenase 1 (IDH1) are found in ~75% of low-grade gliomas and secondary glioblastomas as well as in several other types of cancer. More chemotypes of inhibitors of IDH1(R132H) are therefore needed. OBJECTIVE: To develop a new class of IDH1(R132H) inhibitors as potent antitumor agents. METHOD: A biochemical assay was developed to find inhibitors of IDH1(R132H) mutant enzyme. Chemical synthesis and structure activity relationship studies were used to find compounds with improved potency...
May 23, 2018: Medicinal Chemistry
https://www.readbyqxmd.com/read/29791798/non-natural-linker-configuration-in-2-6-dipeptidyl-anthraquinones-enhances-the-inhibition-of-tar-rna-binding-annealing-activities-by-hiv-1-nc-and-tat-proteins
#4
Alice Sosic, Irene Saccone, Caterina Carraro, Thomas Kenderdine, Elia Gamba, Giuseppe Caliendo, Angela Corvino, Ferdinando Fiorino, Paola DiVaio, Elisa Magli, Elisa Perissutti, Vincenzo Santagada, Beatrice Severino, Valentina Spada, Daniele Fabris, Francesco Frecentese, Barbara Gatto
The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of antiretrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains...
May 23, 2018: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29791142/reassessment-of-the-transport-mechanism-of-the-human-zinc-transporter-slc39a2
#5
Marie Christine Franz, Jonai Pujol-Gimenez, Nicolas Montalbetti, Miguel Fernandez-Tenorio, Timothy R DeGrado, Ernst Niggli, Michael F Romero, Matthias A Hediger
The human zinc transporter SLC39A2, also known as ZIP2, was shown to mediate zinc transport that could be inhibited at pH values below 7.0 and stimulated by HCO3-, suggesting a Zn2+/HCO3- cotransport mechanism (1). In contrast, recent experiments in our laboratory indicated that the functional activity of ZIP2 increases at acidic pH (2). The present study was therefore designed to reexamine the findings on the pH-dependence and to extend the functional characterization of ZIP2. Our current results show that ZIP2-mediated transport is modulated by extracellular pH, but independent of the H+ driving force...
May 23, 2018: Biochemistry
https://www.readbyqxmd.com/read/29790838/release-of-taurine-and-glutamate-contributes-to-cell-volume-regulation-in-human-retinal-m%C3%A3-ller-cells-differences-in-modulation-by-calcium
#6
Vanina Netti, Alejandro Pizzoni, Martha Peréz-Domínguez, Paula Ford, Herminia Pasantes-Morales, Gerardo Ramos-Mandujano, Claudia Capurro
Neuronal activity in the retina generates osmotic gradients that lead to Müller cell swelling, followed by a regulatory volume decrease (RVD) response, partially due to the isoosmotic efflux of KCl and water. However, our previous studies in a human Müller cell line (MIO-M1) demonstrated that an important fraction of RVD may also involve the efflux of organic solutes. We also showed that RVD depends on the swelling-induced Ca2+ release from intracellular stores. Here we investigate the contribution of Taurine (Tau) and Glutamate (Glu), the most relevant amino acids in Müller cells, to RVD through the volume-regulated anion channel (VRAC), as well as their Ca2+ -dependency in MIO-M1 cells...
May 23, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29790111/potential-of-the-dual-mtor-kinase-inhibitor-azd2014-to-overcome-paclitaxel-resistance-in-anaplastic-thyroid-carcinoma
#7
Zorica Milošević, Jasna Banković, Jelena Dinić, Chrisiida Tsimplouli, Evangelia Sereti, Miodrag Dragoj, Verica Paunović, Zorka Milovanović, Marija Stepanović, Nikola Tanić, Kostantinos Dimas, Milica Pešić
PURPOSE: Anaplastic thyroid carcinoma (ATC) is an aggressive, chemo-resistant malignancy. Chemo-resistance is often associated with changes in activity of the RAS/MAPK/ERK and PI3K/AKT/mTOR pathways and/or a high expression of ATP binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). To assess the therapeutic efficacy in ATC of a combination of the dual mTOR kinase inhibitor vistusertib (AZD2014) and paclitaxel (PTX), we generated a new cell line (Rho-) via the selection of human thyroid carcinoma 8505C cells that exhibit a low accumulation of rhodamine 123, which serves as a P-gp and BCRP substrate...
May 22, 2018: Cellular Oncology (Dordrecht)
https://www.readbyqxmd.com/read/29789824/layered-double-hydroxide-poly-dopamine-composite-coating-with-surface-heparinization-on-mg-alloys-improved-anticorrosion-endothelialization-and-hemocompatibility
#8
Hua Li, Feng Peng, Donghui Wang, Yuqin Qiao, Demin Xu, Xuanyong Liu
Magnesium (Mg) and its alloys are promising cardiovascular stent materials due to their favourable physical properties and complete degradation in vivo. However, rapid degradation and poor cytocompatibility hinder their clinical applications. To enhance the corrosion resistance and endothelialization of the AZ31 alloy, a layered double hydroxide (LDH)/poly-dopamine (PDA) composite coating (LDH/PDA) was successfully fabricated. Polarization curves and the electrochemical impedance spectroscopy Nyquist spectrum test proved that the corrosion resistance of the LDH/PDA sample was significantly improved in vitro...
May 23, 2018: Biomaterials Science
https://www.readbyqxmd.com/read/29789397/the-wnt-antagonist-and-secreted-frizzled-related-protein-5-implications-on-lipid-metabolism-inflammation-and-type-2-diabetes-mellitus
#9
Ling-Bin Liu, Xiao-Dong Chen, Xiang-Yu Zhou, Qing Zhu
Various reports have suggested that secreted frizzled-related protein 5 (SFRP5) plays a regulatory role in the processes of cellular proliferation and differentiation, by means of inactivating the Wnt/β-catenin signaling pathway. Recently, SFRP5 has been identified as an anti-inflammatory adipokine, which may be induced during preadipocyte proliferation, differentiation, and maturation. This review aims to identify the recent progress in the research and development of SFRP5 that can play a role in influencing lipid metabolism, inflammation and type 2 diabetes mellitus (T2DM)...
May 22, 2018: Bioscience Reports
https://www.readbyqxmd.com/read/29786968/p62-mediated-autophagy-affects-nutrition-dependent-insulin-receptor-substrate-1-dynamics-in-3t3-l1-preadipocytes
#10
Hirobumi Igawa, Akihiro Kikuchi, Hirofumi Misu, Kiyo-Aki Ishii, Shuichi Kaneko, Toshinari Takamura
AIMS/INTRODUCTION: Previous studies have shown that the organism's nutritional status changes the protein levels of insulin receptor substrate 1 (IRS-1) in a tissue-specific manner. Although the mechanisms underlying the regulation of IRS-1 in the nutrient-rich conditions associated with diabetes and insulin resistance have been well studied, those under nutrient-poor conditions remain unknown. The aim of this study was to investigate how IRS-1 protein levels change depending on the nutritional status of 3T3-L1 preadipocytes...
May 22, 2018: Journal of Diabetes Investigation
https://www.readbyqxmd.com/read/29786857/effect-of-oatp1b1-1b3-inhibitor-gdc-0810-on-the-pharmacokinetics-of-pravastatin-and-coproporphyrin-i-iii-in-healthy-female-subjects
#11
Lichuan Liu, Sravanthi Cheeti, Kenta Yoshida, Edna Choo, Eugene Chen, Buyun Chen, Mary Gates, Stina Singel, Roland Morley, Joseph Ware, Srikumar Sahasranaman
Developed as an oral anticancer drug to treat estrogen receptor-positive breast cancer, GDC-0810 was shown to be a potent inhibitor of organic anion-transporting polypeptide 1B1 and 1B3 (OATP1B1/1B3) from an in vitro assay. A clinical study was conducted to assess the drug-drug interaction potential between GDC-0810 and pravastatin, which is a relatively selective and sensitive OATP1B1/1B3 substrate. Fifteen healthy female subjects of non-childbearing potential were enrolled in the study. On day 1 in period 1, a single 10-mg dose of pravastatin was administered to all subjects...
May 22, 2018: Journal of Clinical Pharmacology
https://www.readbyqxmd.com/read/29785588/sam68-promotes-invasion-migration-and-proliferation-of-fibroblast-like-synoviocytes-by-enhancing-the-nf-%C3%AE%C2%BAb-p65-pathway-in-rheumatoid-arthritis
#12
Weiwei Sun, Rongqin Qin, Rui Wang, Dazhi Ding, Zhaohui Yu, Yuxi Liu, Ruilong Hong, Zhen Cheng, Youhua Wang
Src-associated substrate during mitosis of 68 KDa (Sam68), also known as KH domain containing, RNA binding, signal transduction associated 1 (KHDRBS1), is the prototypic member of the signal transduction activator of RNA (STAR) family of RNA-binding proteins. Previous studies have indicated that Sam68 regulates nuclear transcription factor kappa B (NF-κB) to mediate inflammation. In this study, we analyzed the effect and possible mechanisms of Sam68 in rheumatoid arthritis (RA). By western blot analysis and immunohistochemistry, we found that the expression of Sam68 in synovial tissue of RA patients was increased compared with the control group...
May 21, 2018: Inflammation
https://www.readbyqxmd.com/read/29785468/competition-for-electrons-between-mono-oxygenations-of-pyridine-and-2-hydroxypyridine
#13
Chao Yang, Yingxia Tang, Hua Xu, Ning Yan, Naiyu Li, Yongming Zhang, Bruce E Rittmann
Pyridine and its heterocyclic derivatives are widely encountered in industrial wastewaters, and they are relatively recalcitrant to biodegradation. Pyridine biodegradation is initiated by two mono-oxygenation reactions that compete for intracellular electron donor (2H). In our experiments, UV photolysis of pyridine generated succinate, whose oxidation augmented the intracellular electron donor and accelerated pyridine biodegradation and mineralization. The first mono-oxygenation reaction always was faster than the second one, because electrons provided by intracellular electron donors were preferentially utilized by the first mono-oxygenase; this was true even when the concentration of 2HP was greater than the concentration of pyridine...
May 21, 2018: Biodegradation
https://www.readbyqxmd.com/read/29784887/identification-of-the-thioredoxin-partner-of-vkor-in-mycobacterial-disulfide-bond-formation
#14
Na Ke, Cristina Landeta, Xiaoyun Wang, Dana Boyd, Markus Eser, Jon Beckwith
Disulfide bonds influence stability and activity of many proteins. In Escherichia coli the DsbA and DsbB enzymes promote disulfide bond formation. Other bacteria, including the Actinobacteria, use instead of DsbB the enzyme VKOR (Vitamin K Epoxide Reductase), which is found either fused to or encoded in the same operon as a dsbA -like protein. Mycobacterium tuberculosis and other gram-positive Actinobacteria secrete to the cell envelope many proteins with even numbers of cysteines. These organisms have predicted oxidoreductases and VKOR orthologs...
May 21, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29783059/disruption-of-medial-septum-and-diagonal-bands-of-broca-cholinergic-projections-to-the-ventral-hippocampus-disrupt-auditory-fear-memory
#15
Jennifer M Staib, Rebecca Della Valle, Dayan K Knox
In classical fear conditioning, a neutral conditioned stimulus (CS) is paired with an aversive unconditioned stimulus (US), which leads to a fear memory. If the CS is repeatedly presented without the US after fear conditioning, the formation of an extinction memory occurs, which inhibits fear memory expression. A previous study has demonstrated that selective cholinergic lesions in the medial septum and vertical limb of the diagonal bands of Broca (MS/vDBB) prior to fear and extinction learning disrupt contextual fear memory discrimination and acquisition of extinction memory...
May 18, 2018: Neurobiology of Learning and Memory
https://www.readbyqxmd.com/read/29782822/simultaneous-determination-of-intestinal-permeability-and-potential-drug-interactions-of-complex-mixtures-using-caco-2-cells-and-high-resolution-mass-spectrometry-studies-with-rauwolfia-serpentina-extract
#16
Thomas J Flynn, Sanah N Vohra
Caco-2 cells are a commonly used model for estimating the intestinal bioavailability of single chemical entity pharmaceuticals. Caco-2 cells, when induced with calcitriol, also express other biological functions such as phase I (CYP) and phase II (glucuronosyltransferases) drug metabolizing enzymes which are relevant to drug-supplement interactions. Intestinal bioavailability is an important factor in the overall safety assessment of products consumed orally. Foods, including herbal dietary supplements, are complex substances with multiple chemical components...
May 18, 2018: Chemico-biological Interactions
https://www.readbyqxmd.com/read/29782790/magnetite-triggering-enhanced-diet-a-scavenger-for-the-blockage-of-electron-transfer-in-anaerobic-digestion-of-high-solids-sewage-sludge
#17
Tao Wang, Dong Zhang, Lingling Dai, Bin Dong, Xiaohu Dai
At present, high-solids anaerobic digestion of sewage sludge has drawn great attention due to the superiority of its small land area footprint and low energy consumption. However, a high organic loading rate may cause acids accumulation and ammonia inhibition, thus leading to an inhibited pseudo-steady state in which electron transfer through interspecies hydrogen transfer (IHT) between acetogens and methanogens is blocked. In this study, adding 50 mg/g TS (total solid) magnetite clearly reduced the accumulation of short-chain fatty acids and accelerated methane production by 26...
May 21, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29782695/dual-ag-zno-decorated-micro-nanoporous-sulfonated-polyetheretherketone-with-superior-antibacterial-capability-and-biocompatibility-via-layer-by-layer-self-assembly-strategy
#18
Yi Deng, Lei Yang, Xiaobing Huang, Junhong Chen, Xiuyuan Shi, Weizhong Yang, Min Hong, Yuan Wang, Matthew S Dargusch, Zhi-Gang Chen
Polyetheretherketone is attractive for dental and orthopedic applications due to its mechanical attributes close to that of human bone; however, the lack of antibacterial capability and bioactivity of polyetheretherketone has substantially impeded its clinical applications. Here, a dual therapy implant coating is developed on the 3D micro-/nanoporous sulfonated polyetheretherketone via layer-by-layer self-assembly of Ag ions and Zn ions. Material characterization studies have indicated that nanoparticles consisting of elemental Ag and ZnO are uniformly incorporated on the porous sulfonated polyetheretherketone surface...
May 21, 2018: Macromolecular Bioscience
https://www.readbyqxmd.com/read/29782177/synthesis-of-%C3%AE-%C3%AE-difluorinated-phosphonate-pser-pthr-mimetics-via-rhodium-catalyzed-asymmetric-hydrogenation-of-%C3%AE-difluorophosphonomethyl-%C3%AE-acylamino-acrylates
#19
Hong-Xue Chen, Jie Kang, Rong Chang, Yun-Lai Zhang, Hua-Zhen Duan, Yan-Mei Li, Yong-Xiang Chen
A novel and facile synthetic strategy for α,α-difluorinated phosphonate mimetics of phosphoserine/phosphothreonine utilizing rhodium-catalyzed asymmetric hydrogenation was developed. The dehydrogenated substrate β-difluorophosphonomethyl α-(acylamino)acrylates were first prepared from protected serine/threonine followed by asymmetric hydrogenation using the rhodium-DuPhos catalytic system to generate the chiral center(s). These important phosphonate building blocks were successfully incorporated into phosphatase-resistant peptides, which displayed similar inhibition to the 14-3-3 ζ protein as the parent pSer/pThr peptides...
May 21, 2018: Organic Letters
https://www.readbyqxmd.com/read/29781767/activities-of-purine-converting-enzymes-in-heart-liver-and-kidney-mice-ldlr-and-apo-e
#20
I M Rybakowska, B Kutryb-Zając, R Milczarek, B Łukasz, E M Slominska, R T Smolenski
Nucleotide metabolism plays a major role in a number of vital cellular processes such as energetics. This, in turn, is important in pathologies such as atherosclerosis. Three month old atherosclerotic mice with knock outs for LDLR and apolipoprotein E (ApoE) were used for the experiments. Activities of AMP-deaminase (AMPD), ecto5'-nucleotidase (e5NT), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP) were measured in heart, liver and kidney cortex and medulla by analysing conversion of substrates into products using HPLC...
May 21, 2018: Nucleosides, Nucleotides & Nucleic Acids
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