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https://www.readbyqxmd.com/read/28916792/smartflares-fail-to-reflect-their-target-transcripts-levels
#1
Maria Czarnek, Joanna Bereta
SmartFlare probes have recently emerged as a promising tool for visualisation and quantification of specific RNAs in living cells. They are supposed to overcome the common drawbacks of current methods for RNA analysis: the need of cell fixation or lysis, or the requirements for genetic manipulations. In contrast to the traditional methods, SmartFlare probes are also presumed to provide information on RNA levels in single cells. Disappointingly, the results of our comprehensive study involving probes specific to five different transcripts, HMOX1, IL6, PTGS2, Nrg1, and ERBB4, deny the usefulness of SmartFlare probes for RNA analysis...
September 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28916034/colorimetric-biosensor-based-on-a-dnazyme-primer-and-its-application-in-logic-gate-operations-for-dna-screening
#2
Chenguang Wang, Nan Cheng, Longjiao Zhu, Yuancong Xu, Kunlun Huang, Pengyu Zhu, Shuifang Zhu, Wei Fu, Wentao Xu
A colorimetric biosensor for DNA screening was designed based on the conformational changes of the horseradish peroxidase (HRP)-mimicking DNAzyme. The scheme of DNA biosensing was designed based on the base pairing of DNAzyme sequence to inhibit the formation of HRP-mimicking hemin/G-quadruplex structures in the process of amplification. DNA could be amplified via the universal primer multiplex polymerase chain reaction (UP-M-PCR) and innovatively detected as color disappear in the reaction visible to the naked eye...
September 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28879360/target-induced-cyclic-dnazyme-formation-for-colorimetric-and-chemiluminescence-imaging-assay-of-protein-biomarkers
#3
Kaili Yang, Min Huo, Yuehua Guo, Yizhuo Yang, Jie Wu, Lin Ding, Huangxian Ju
A target-induced cyclic strategy for DNAzyme formation was proposed to achieve simple, sensitive and universal detection of protein biomarkers with convenient colorimetric or chemiluminescence imaging readout. In the assay, the target protein was recognized by a pair of DNA-labeled antibodies (Ab1-DNA1 and Ab2-DNA2) to form a proximate complex, which could hybridize with the conjugate DNA3/DNA4 to release the guanine-rich DNA4 and thus formed G-quadruplex/hemin horseradish peroxidase-mimicking DNAzyme. The process could be further recycled with Exonuclease III by cleaving DNA3 to free the proximate complex, resulting in the cyclic formation of DNAzyme...
September 7, 2017: Analyst
https://www.readbyqxmd.com/read/28876926/cryo-ir-spectroscopy-of-hemin-complexes-in-isolation
#4
Sebastian Dillinger, Johannes Lang, Gereon Niedner-Schatteburg
We present cryo IR spectra of isolated [Hemin](+) adducts with CO, N2, and O2 ([Hemin(CO)1](+), [Hemin(CO)2](+), [Hemin((14)N2)](+), [Hemin((15)N2)](+), and [Hemin(O2)](+)). Well resolved bands allow for the elucidation of structure and spin multiplicity in conjunction with density functional (DFT) calculations. There is a quartet spin state for the N2 and CO adducts and a sextet spin state for the O2 adduct, where the O2 retains its triplet state. The double CO adsorption induces significant changes in the vibrational patterns of the IR spectra, which we take as strong evidence for a spin quenching into a doublet...
September 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28871452/click-chemistry-mediated-cyclic-cleavage-of-metal-ion-dependent-dnazymes-for-amplified-and-colorimetric-detection-of-human-serum-copper-ii
#5
Daxiu Li, Jiaqing Xie, Wenjiao Zhou, Bingying Jiang, Ruo Yuan, Yun Xiang
The determination of the level of Cu(2+) plays important roles in disease diagnosis and environmental monitoring. By coupling Cu(+)-catalyzed click chemistry and metal ion-dependent DNAzyme cyclic amplification, we have developed a convenient and sensitive colorimetric sensing method for the detection of Cu(2+) in human serums. The target Cu(2+) can be reduced by ascorbate to form Cu(+), which catalyzes the azide-alkyne cycloaddition between the azide- and alkyne-modified DNAs to form Mg(2+)-dependent DNAzymes...
September 4, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28870318/assay-of-dna-methyltransferase-1-activity-based-on-uracil-specific-excision-reagent-digestion-induced-g-quadruplex-formation
#6
Jinlong Li, Guangwu He, Chaoli Mu, Keming Wang, Yang Xiang
DNA methylation catalyzed by DNA methyltransferase plays an important role in many biological processes including gene transcription, genomic imprinting and cellular differentiation. Herein, a novel and effective electrochemical method for the assay of DNA methyltransferase 1(DNMT1) activity has been successfully developed by using uracil-specific excision reagent (USER) induced G-quadruplex formation. Briefly, double stranded DNA containing the recognition sequence of DNMT1 is immobilized on the electrode...
September 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28868064/hydrogen-peroxide-is-involved-in-%C3%AE-cyclodextrin-hemin-complex-induced-lateral-root-formation-in-tomato-seedlings
#7
Weiti Cui, Dan Zhu, Wenbiao Shen, Yudong Mei, Dekun Hu, Yujian Shi, Yong Ren, Wei Shen, Quan Gu, Daokun Xu, Liqin Huang
Although previous results showed that β-cyclodextrin-hemin complex (β-CDH) could induce tomato lateral root (LR) formation, the corresponding downstream messengers are still not fully understood. In this report, similar to the inducing effects of exogenously applied hydrogen peroxide (H2O2), we discovered that β-CDH elicited RBOH1 transcript upregulation, endogenous H2O2 accumulation, and thereafter tomato LR development. Above responses were sensitive to dimethylthiourea (DMTU) and ascorbic acid (AsA), two membrane-permeable scavengers of H2O2, showing that accumulation of H2O2 and LR formation were significantly blocked...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28863941/potential-role-of-ferric-hemoglobin-in-ms-pathogenesis-effects-of-oxidative-stress-and-extracellular-methemoglobin-or-its-degradation-products-on-myelin-components
#8
Vladimir V Bamm, Mary E L Henein, Shannon L J Sproul, Danielle K Lanthier, George Harauz
There is a well-documented relationship between cerebral vasculature and multiple sclerosis (MS) lesions: abnormal accumulations of iron have been found in the walls of the dilated veins in cerebral MS plaques. The source of this iron is unknown, but could be related to the recognized phenomenon of capillary and venous hemorrhages leading to blood extravasation. In turn, hemorrhaging leading to hemolysis results in extracellular release of hemoglobin, a reactive molecule that could induce local oxidative stress, inflammation, and tissue damage...
August 31, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28853193/peroxidyme-amplified-radical-chain-reaction-parcr-nested-photochemical-and-biochemical-positive-feedback
#9
John P Goertz, Ian White
We present Peroxidyme Amplified Radical Chain Reaction (PARCR), a novel enzyme-free system that achieves exponential amplification of a visible signal. Typical enzyme-free amplification systems that produce a visible readout suffer from long reaction times, low sensitivity, and narrow dynamic range. PARCR employs photocatalyzed non-linear signal generation, enabling unprecedented one-pot, naked-eye detection of a catalytic reporter from 1 µM down to 100 pM. In this reaction, hemin-binding peroxidase-mimicking DNAzymes ("peroxidymes") mediate the NADH-driven oxidation of a colorless, non-fluorescent phenoxazine dye (Amplex Red) to a brightly colored, strongly fluorescent product (resorufin); illumination with green light initiates multiple radical-forming positive-feedback loops, rapidly producing visible levels of resorufin...
August 29, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28852807/construction-of-a-highly-sensitive-signal-on-aptasensor-based-on-gold-nanoparticles-functionalized-silica-nanoparticles-for-selective-detection-of-tryptophan
#10
Ayemeh Bagheri Hashkavayi, Jahan Bakhsh Raoof, Reza Ojani
In this work, a highly sensitive, low-cost, and label-free aptasensor based on signal-on mechanisms of response was developed by immobilizing the aptamer on gold nanoparticles (AuNPs)/amine-functionalized silica nanoparticle (FSN)/screen-printed electrode (SPE) surface for highly selective electrochemical detection of tryptophan (Trp). The hemin (Hem), which interacted with the guanine bases of the aptamer, worked as a redox indicator to generate a readable electrochemical signal. The changes in the charge transfer resistance have been monitored using the voltammetry and electrochemical impedance spectroscopic (EIS) techniques...
August 29, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28845425/having-your-cake-and-eating-it-staphylococcus-aureus-small-colony-variants-can-evolve-faster-growth-rate-without-losing-their-antibiotic-resistance
#11
COMMENT
Gerrit Brandis, Sha Cao, Douglas L Huseby, Diarmaid Hughes
Staphylococcus aureus can produce small colony variants (SCVs) during infections. These cause significant clinical problems because they are difficult to detect in standard microbiological screening and are associated with persistent infections. The major causes of the SCV phenotype are mutations that inhibit respiration by inactivation of genes of the menadione or hemin biosynthesis pathways. This reduces the production of ATP required to support fast growth. Importantly, it also decreases cross-membrane potential in SCVs, resulting in decreased uptake of cationic compounds, with reduced susceptibility to aminoglycoside antibiotics as a consequence...
August 1, 2017: Microbial Cell
https://www.readbyqxmd.com/read/28836936/protective-effects-of-heme-oxygenase-1-against-severe-acute-pancreatitis-via-inhibition-of-tumor-necrosis-factor-%C3%AE-and-augmentation-of-interleukin-10
#12
Fei-Hu Zhang, Yu-Han Sun, Kai-Liang Fan, Xiao-Bin Dong, Ning Han, Hao Zhao, Li Kong
BACKGROUND: Heme oxygenase-1 (HO-1) is an inducible defense gene which plays a significant role in inflammation. HO-1 protects cells and tissues through the mechanism of anti-oxidation, maintaining microcirculation and anti-inflammation. The aim of the current study is to investigate the role of HO-1 on systemic inflammatory response in severe acute pancreatitis (SAP). METHODS: Forty male Sprague-Dawley (SD) rats were randomly assigned into four groups: control group (n = 10); SAP group (n = 10), SAP model was induced by retrograde injection of 3% sodium taurocholate through pancreatic duct; HO-1 stimulation group (n = 10), SD rats were injected 75 μg/kg hemin intraperitoneally 30 min after induction of SAP; HO-1 inhibition group (n = 10), SD rats were injected 20 μg/kg Zinc porphyrin (Zn-PP) intraperitoneally 30 min after induction of SAP...
August 24, 2017: BMC Gastroenterology
https://www.readbyqxmd.com/read/28835449/fluorescence-quenching-by-metal-centered-porphyrins-and-poryphyrin-enzymes
#13
Kenneth R Olson, Yan Gao, Faihaan Arif, Kanika Arora, Shivali Patel, Eric R DeLeon, Karl D Straub
Fluorescence spectroscopy and microscopy has been used extensively to monitor biomolecules, especially reactive oxygen species (ROS) and more recently reactive sulfide (RSS) species. Nearly all fluorophores are either excited by or emit light between 450 and 550 nm which is similar to the absorbance of heme proteins and metal-centered porphyrins. Here we examined the effects of catalase (Cat), reduced and oxidized hemoglobin (Hb and metHb), albumin (alb), manganese (III) Tetrakis (4-Benzoic Acid) porphyrin chloride (MnTBAP), iron proto-porphyrin IX (hemin) and copper proto-porphyrin IX (CuPPIX) on the fluorescence properties of fluorescein...
August 23, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28829595/factors-affecting-lipid-oxidation-due-to-pig-and-turkey-hemolysate
#14
Haizhou Wu, Jie Yin, Jianhao Zhang, Mark P Richards
Turkey hemolysate promoted lipid oxidation in washed muscle more effectively than pig hemolysate, which was partly attributed to the greater ability of H2O2 that formed during auto-oxidation to oxidize the avian hemoglobin (Hb). Turkey and pig hemolysate (2.5 μM Hb) exposed to 10 μM H2O2 oxidized to 48% and 4% metHb, respectively. Catalase activity, which converts H2O2 to water, was elevated in the pig hemolysate. The larger difference in Hb oxidation when comparing turkey and pig hemolysate in washed muscle (relative to their auto-oxidation rates) suggested that lipid oxidation products facilitated formation of metHb...
August 30, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28827166/hemin-is-able-to-disaggregate-lysozyme-amyloid-fibrils-into-monomers
#15
Sumalata Sonavane, Syeda Zehra Haider, Anil Kumar, Basir Ahmad
Lysozyme amyloidosis (ALys) is a disease of the gastrointestinal tract, liver and kidneys, which is caused by the accumulation of insoluble fibrils of lysozyme in the tissues of above organs. The ALys can be cured by disintegration and clearance of the fibrils from the affected tissues and organs. It is thought that protein fibrils are extremely stable. Consequently, small molecule-induced dissociation of fibrils under physiological conditions is really challenging. Here, we report kinetic and thermodynamic analyses of hemin-induced dissociation of hen egg white lysozyme amyloid fibrils...
August 18, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28814160/elucidation-of-molecular-mechanism-of-stability-of-the-heme-regulated-eif2%C3%AE-kinase-upon-binding-of-its-ligand-hemin-in-its-catalytic-kinase-domain
#16
Varsha Bhavnani, Kaviraj Swarnendu, Priyabrata Panigrahi, C G Suresh, SuneelShekar Yapara, Jayanta Pal
The eIF2α kinase activity of the heme-regulated inhibitor (HRI) is regulated by heme which makes it a unique member of the family of eIF2α kinases. Since heme concentrations create an equilibrium for the kinase to be active/inactive, it becomes important to study the heme binding effects upon the kinase and understanding its mechanism of functionality. In the present study, we report the thermostability achieved by the catalytic kinase domain of HRI (HRI.CKD) upon ligand (heme) binding. Our CD data demonstrates that the HRI...
August 17, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28800505/electrochemical-aptasensor-for-thrombin-using-co-catalysis-of-hemin-g-quadruplex-dnazyme-and-octahedral-cu2o-au-nanocomposites-for-signal-amplification
#17
Shuai Chen, Pin Liu, Kewen Su, Xuan Li, Zhen Qin, Wei Xu, Jun Chen, Chaorui Li, Jingfu Qiu
In this work, novel octahedral Cu2O-Au nanocomposites were synthesized and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of a DNAzyme for signal amplification. The octahedral Cu2O-Au nanocomposites have not only simultaneously served as signal amplifying molecules but have also been utilized as an ideal loading platform to immobilize a large number of electroactive substances and recognition probes. Gold nanoparticles (AuNPs) were grown directly on the surface of the octahedral Cu2O nanocrystals, and the Cu2O-Au nanocomposites obtained had the advantages of large surface areas and excellent biocompatibilities...
August 5, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28799583/evidence-and-isolation-of-tetrahedral-intermediates-formed-upon-the-addition-of-lithium-carbenoids-to-weinreb-amides-and-n-acylpyrroles
#18
Laura Castoldi, Wolfgang Holzer, Thierry Langer, Vittorio Pace
The tetrahedral intermediates generated upon the addition of halolithium carbenoids (LiCH2X and LiCHXY) to Weinreb amides have been intercepted and fully characterized as O-TMS heminals. The commercially available N-trimethylsilyl imidazole is the ideal trapping agent whose employment, combined with a straightforward neutral Alox chromatographic purification, enables the isolation of such labile species. The procedure could be advantageously extended also for obtaining O-TMS heminals from N-acylpyrroles. These intermediates manifest interesting reactivity including as precursors of more complex carbenoids...
August 22, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28782507/mapk-jnk1-activation-protects-cells-against-cadmium-induced-autophagic-cell-death-via-differential-regulation-of-catalase-and-heme-oxygenase-1-in-oral-cancer-cells
#19
Keum-Young So, Sang-Hun Kim, Ki-Tae Jung, Hyun-Young Lee, Seon-Hee Oh
Antioxidant enzymes are related to oral diseases. We investigated the roles of heme oxygenase-1 (HO-1) and catalase in cadmium (Cd)-induced oxidative stress and the underlying molecular mechanism in oral cancer cells. Exposing YD8 cells to Cd reduced the expression levels of catalase and superoxide dismutase 1/2 and induced the expression of HO-1 as well as autophagy and apoptosis, which were reversed by N-acetyl-l-cysteine (NAC). Cd-exposed YD10B cells exhibited milder effects than YD8 cells, indicating that Cd sensitivity is associated with antioxidant enzymes and autophagy...
October 1, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28771786/case-of-mycobacterium-haemophilum-misdiagnosed-as-mycobacterium-intracellulare-due-to-one-base-insertion-in-the-bacterial-genome
#20
Rika Nishikawa, Yozo Yamada, Haruhisa Kanki, Hiroshi Matsuoka, Tatsuya Nakamura, Takumi Jikimoto, Mari Kusuki, Norihisa Ishii, Kenichiro Ohnuma, Kazue Nakanaga, Chikako Nishigori
Mycobacterium haemophilum is a slow-growing, non-tuberculous mycobacteria that causes cutaneous infection. We describe a case of cutaneous infection in a 68-year-old Japanese man with polymyositis. This was caused by M. haemophilum harboring one base insertion in gene sequence. At first, the causal microorganism was misidentified as M. intracellulare by COBAS(®) TaqMan(®) MAI test. However, poor growth on Ogawa media and growth enhancement on 7H11C agar around a hemin-containing disk prompted us to reinvestigate the causal microorganisms, which were revealed to be M...
August 3, 2017: Journal of Dermatology
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