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https://www.readbyqxmd.com/read/28532053/functionalized-fe3o4-graphene-oxide-nanocomposites-with-hairpin-aptamers-for-the-separation-and-preconcentration-of-trace-pb-2-from-biological-samples-prior-to-determination-by-icp-ms
#1
Mojtaba Shamsipur, Leila Farzin, Mahmoud Amouzadeh Tabrizi, Shahab Sheibani
Lead (Pb) as a topically poisonous metal represents a serious threat to the ecological environment and especially to human beings. Therefore, it is urgent to develop a rapid and reliable monitoring technique for this heavy metal in the environmental samples. In the present study, we have designed a selective and sensitive method for the determination of ultratrace contents of Pb(2+) in biological samples, based on the guanine (G)-quadruplex formed by the aptamer with hairpin structure and Pb(2+). For this purpose, Pb(2+) specific aptamer serving as affinity probe to capture and separate trace amounts of the analyte, was covalently linked to Fe3O4/graphene oxide (GO) surface by using a suitable cross-linking agent...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28530384/divalent-metal-ion-activation-of-a-guanine-general-base-in-the-hammerhead-ribozyme-insights-from-molecular-simulations
#2
Haoyuan Chen, Timothy J Giese, Barbara L Golden, Darrin M York
The hammerhead ribozyme is a well-studied nucleolytic ribozyme that catalyzes the self-cleavage of the RNA phosphodiester backbone. Despite experimental and theoretical efforts, there remain key questions about details of the mechanism with regard to the activation of the nucleophile by the putative general base guanine (G12). Straight-forward interpretation of the measured activity-pH data implies the pKa value of the N1 position in the G12 nucleobase is significantly shifted by the ribozyme environment. Recent crystallographic and biochemical work has identified pH-dependent divalent metal ion binding at the N7/O6 position of G12, leading to the hypothesis that this binding mode could induce a pKa shift of G12 towards neutrality...
May 22, 2017: Biochemistry
https://www.readbyqxmd.com/read/28529131/the-structure-of-the-guanidine-ii-riboswitch
#3
Lin Huang, Jia Wang, David M J Lilley
The guanidine-II (mini-ykkC) riboswitch is the smallest of the guanidine-responsive riboswitches, comprising two stem loops of similar sequence. We have solved high-resolution crystal structures of both stem loops for the riboswitch from Gloeobacter violaceus. The stem loops have a strong propensity to dimerize by intimate loop-loop interaction. The dimerization creates specific binding pockets for two guanidine molecules, explaining their cooperative binding. Within the binding pockets the ligands are hydrogen bonded to a guanine at O6 and N7, and to successive backbone phosphates...
May 18, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28528357/cerebellar-gray-matter-alterations-in-huntington-disease-a-voxel-based-morphometry-study
#4
Paula C de Azevedo, Rachel P Guimarães, Camila C Piccinin, Luiza G Piovesana, Lidiane S Campos, Juliana R Zuiani, Eliza M Tamashiro, Giordanna Pinheiro, Augusto C Amato-Filho, Fernando Cendes, Iscia Lopes-Cendes, Anelyssa D'Abreu
Neuropathological and neuroimaging studies in Huntington disease (HD) have suggested a role for the cerebellum. Our goal was to perform a detailed evaluation of cerebellar morphology. We performed the Unified HD rating scale (UHDRS) and Montreal cognitive assessment (MOCA) in 26 HD patients and 26 healthy controls. We created a two-sample test to analyze cerebellar gray matter (GM) differences between groups and another to correlate GM alterations with UHDRS and MOCA, corrected for age, expanded cytosine-adenine-guanine repeats, and disease duration using the spatially unbiased atlas template (SUIT)-SPM-toolbox which preserves anatomical detailing...
May 20, 2017: Cerebellum
https://www.readbyqxmd.com/read/28526774/preliminary-evaluation-of-cytosine-phosphate-guanine-oligodeoxynucleotides-bound-to-gelatine-nanoparticles-as-immunotherapy-for-canine-atopic-dermatitis
#5
I Wagner, K J Geh, M Hubert, G Winter, K Weber, J Classen, C Klinger, R S Mueller
Cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN) are a promising new immunotherapeutic treatment option for canine atopic dermatitis (AD). The aim of this uncontrolled pilot study was to evaluate clinical and immunological effects of gelatine nanoparticle (GNP)-bound CpG ODN (CpG GNP) on atopic dogs. Eighteen dogs with AD were treated for 8 weeks (group 1, n=8) or 18 weeks (group 2, n=10). Before inclusion and after 2 weeks, 4 weeks, 6 weeks (group 1+2), 8 weeks, 12 weeks and 16 weeks (group 2) 75 µg CpG ODN/dog (bound to 1...
May 19, 2017: Veterinary Record
https://www.readbyqxmd.com/read/28526238/ric8a-is-essential-for-the-organisation-of-actin-cytoskeleton-and-cell-matrix-interaction
#6
Katrin Ruisu, Riho Meier, Keiu Kask, Tambet Tõnissoo, Teet Velling, Margus Pooga
RIC8A functions as a chaperone and guanine nucleotide exchange factor for a subset of G protein α subunits. Multiple G protein subunits mediate various signalling events that regulate cell adhesion and migration and the involvement of RIC8A in some of these processes has been demonstrated. We have previously shown that the deficiency of RIC8A causes a failure in mouse gastrulation and neurogenesis - major events in embryogenesis that rely on proper association of cells with the extracellular matrix (ECM) and involve active cell migration...
May 16, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28524722/lesch-nyhan-disease-in-two-families-from-chilo%C3%A3-island-with-mutations-in-the-hprt1-gene
#7
Khue Vu Nguyen, Sebastian Silva, Monica Troncoso, Robert K Naviaux, William L Nyhan
Lesch-Nyhan disease (LND) is a rare X-linked inherited neurogenetic disorder of purine metabolism in which the enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGprt) is defective. The authors report two independent point mutations leading to splicing errors: IVS 2 +1G>A, c.134 +1G>A, and IVS 3 +1G>A, c.318 +1G>A in the hypoxanthine-phosphoribosyltransferase1 (HPRT1) gene which result in exclusion of exon 2 and exon 3 respectively, in the HGprt enzyme protein from different members of two Chiloé Island families...
May 19, 2017: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/28523202/identification-of-a-novel-alternatively-spliced-form-of-inflammatory-regulator-swap-70-like-adapter-of-t-cells
#8
Marie Hashimoto, Jun-Ichi Nagao, Shojiro Ikezaki, Sonoko Tasaki, Ken-Ichi Arita-Morioka, Yuka Narita, Tamaki Cho, Kenji Yuasa, Amnon Altman, Yoshihiko Tanaka
Activation of naive CD4(+) T cells results in the development of several distinct subsets of effector Th cells, including Th2 cells that play a pivotal role in allergic inflammation and helminthic infections. SWAP-70-like adapter of T cells (SLAT), also known as Def6 or IBP, is a guanine nucleotide exchange factor for small GTPases, which regulates CD4(+) T cell inflammatory responses by controlling Ca(2+)/NFAT signaling. In this study, we have identified a novel alternatively spliced isoform of SLAT, named SLAT2, which lacks the region encoded by exons 2-7 of the Def6 gene...
2017: International Journal of Inflammation
https://www.readbyqxmd.com/read/28521592/molecular-perturbation-strategies-to-examine-spatiotemporal-features-of-rho-gef-and-rho-gtpase-activity-in-living-cells
#9
Joachim Goedhart, Jakobus van Unen
Much of our current knowledge of Rho GTPase networks and the regulation by Rho guanine exchange factors (Rho GEFs) and Rho GTPase activating proteins (Rho GAPs) is based on population-based techniques. Over the last decades, technologies that enable single cell analysis with high spatial and temporal resolution have revealed that Rho GTPase activity in cells is regulated on second timescales and at submicrometer length scales. Therefore, perturbation methods with matching spatial and temporal resolution are crucial to further our understanding of Rho GTPase signaling...
May 19, 2017: Small GTPases
https://www.readbyqxmd.com/read/28521481/increased-methylation-of-human-papillomavirus-type-16-dna-is-associated-with-the-severity-of-cervical-lesions-in-infected-females-from-northeast-china
#10
Wei Wang, Zhengrong Sun, Jianhua Liu, Guili Wang, Zhitao Lu, Weiqiang Zhou, Te Qi, Qiang Ruan
Hypermethylation of the cytosine-phosphate-guanine (CpG) sites located at the 3'-major capsid protein L1 (3'L1) and the long control region (LCR) of the human papillomavirus (HPV) genome may be associated with the progression of cervical cancer (CC). However, the methylation status of the LCR of HPV type 16 DNA remains to be elucidated in an infected Chinese population. The aim of the present study was to investigate the association between methylation of the HPV 16 L1 gene and LCR, and the severity of cervical lesions in infected female patients...
May 2017: Oncology Letters
https://www.readbyqxmd.com/read/28516903/molecular-mechanism-of-g%C3%AE-i-activation-by-non-gpcr-proteins-with-a-g%C3%AE-binding-and-activating-motif
#11
Alain Ibáñez de Opakua, Kshitij Parag-Sharma, Vincent DiGiacomo, Nekane Merino, Anthony Leyme, Arthur Marivin, Maider Villate, Lien T Nguyen, Miguel Angel de la Cruz-Morcillo, Juan B Blanco-Canosa, Sekar Ramachandran, George S Baillie, Richard A Cerione, Francisco J Blanco, Mikel Garcia-Marcos
Heterotrimeric G proteins are quintessential signalling switches activated by nucleotide exchange on Gα. Although activation is predominantly carried out by G-protein-coupled receptors (GPCRs), non-receptor guanine-nucleotide exchange factors (GEFs) have emerged as critical signalling molecules and therapeutic targets. Here we characterize the molecular mechanism of G-protein activation by a family of non-receptor GEFs containing a Gα-binding and -activating (GBA) motif. We combine NMR spectroscopy, computational modelling and biochemistry to map changes in Gα caused by binding of GBA proteins with residue-level resolution...
May 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28512143/diverse-roles-of-guanine-nucleotide-exchange-factors-in-regulating-collective-cell-migration
#12
Assaf Zaritsky, Yun-Yu Tseng, M Angeles Rabadán, Shefali Krishna, Michael Overholtzer, Gaudenz Danuser, Alan Hall
Efficient collective migration depends on a balance between contractility and cytoskeletal rearrangements, adhesion, and mechanical cell-cell communication, all controlled by GTPases of the RHO family. By comprehensive screening of guanine nucleotide exchange factors (GEFs) in human bronchial epithelial cell monolayers, we identified GEFs that are required for collective migration at large, such as SOS1 and β-PIX, and RHOA GEFs that are implicated in intercellular communication. Down-regulation of the latter GEFs differentially enhanced front-to-back propagation of guidance cues through the monolayer and was mirrored by down-regulation of RHOA expression and myosin II activity...
May 16, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28511963/sirna-targeting-net1-reduces-the-angiogenesis-and-tumor-growth-of-in-vivo-cervical-squamous-cell-carcinoma-through-vegf-down-regulation
#13
Yuting Zhang, Pei Xia, Wenhui Zhang, Min Yan, Xiujuan Xiong, Weiwei Yu, Enlin Song
Net1, a guanine nucleotide exchange factor, is implicated in cancer cell invasion through activation of RhoA. However, there is still no report on the association between Net1 and cancer angiogenesis. The current study was designed to explore the roles of Net1 in the angiogenesis of cervical squamous cell carcinoma (CSCC) and further observe the effects of Net1 siRNA on the tumor growth. Net1 was overexpressed in CSCC samples (n=80), correlated to the cancer microvessel density (MVD, r=0.223, P=.026) and related to aggressive clinical behaviors, including depth of cervical wall invasion (P=...
May 13, 2017: Human Pathology
https://www.readbyqxmd.com/read/28511928/rational-design-of-nanoparticles-towards-targeting-antigen-presenting-cells-and-improved-t-cell-priming
#14
Eva Zupančič, Caterina Curato, Maria Paisana, Catarina Rodrigues, Ziv Porat, Ana S Viana, Carlos A M Afonso, João Pinto, Rogério Gaspar, João N Moreira, Ronit Satchi-Fainaro, Steffen Jung, Helena F Florindo
Vaccination is a promising strategy to trigger and boost immune responses against cancer or infectious disease. We have designed, synthesized and characterized aliphatic-polyester (poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to investigate how the nature of protein association (adsorbed versus entrapped) and polymer/surfactant concentrations impact on the generation and modulation of antigen-specific immune responses. The ability of the NP formulations to target dendritic cells (DC), be internalized and activate the T cells was characterized and optimized in vitro and in vivo using markers of DC activation and co-stimulatory molecules...
May 13, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28508122/a-trivalent-enzymatic-system-for-uricolytic-therapy-of-hprt-deficiency-and-lesch-nyhan-disease
#15
Luca Ronda, Marialaura Marchetti, Riccardo Piano, Anastasia Liuzzi, Romina Corsini, Riccardo Percudani, Stefano Bettati
PURPOSE: Because of the evolutionary loss of the uricolytic pathway, humans accumulate poorly soluble urate as the final product of purine catabolism. Restoration of uricolysis through enzyme therapy is a promising treatment for severe hyperuricemia caused by deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT). To this end, we studied the effect of PEG conjugation on the activity and stability of the enzymatic complement required for conversion of urate into the more soluble (S)-allantoin...
May 15, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28507547/deletion-of-dock10-in-b-cells-results-in-normal-development-but-a-mild-deficiency-upon-in-vivo-and-in-vitro-stimulations
#16
Natalija Gerasimčik, Minghui He, Marisa A P Baptista, Eva Severinson, Lisa S Westerberg
We sought to identify genes necessary to induce cytoskeletal change in B cells. Using gene expression microarray, we compared B cells stimulated with interleukin-4 (IL-4) and anti-CD40 antibodies that induce B cell spreading, cell motility, tight aggregates, and extensive microvilli with B cells stimulated with lipopolysaccharide that lack these cytoskeletal changes. We identified 84 genes with 10-fold or greater expression in anti-CD40 + IL-4 stimulated B cells, one of these encoded the guanine nucleotide exchange factor (GEF) dedicator of cytokinesis 10 (Dock10)...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28506525/how-does-mg-2-modulate-the-rna-folding-mechanism-a-case-study-of-the-g-c-w-w-trans-basepair
#17
Antarip Halder, Rohit Roy, Dhananjay Bhattacharyya, Abhijit Mitra
Reverse Watson-Crick G:C basepairs (G:C W:W Trans) occur frequently in different functional RNAs. This is one of the few basepairs whose gas-phase-optimized isolated geometry is inconsistent with the corresponding experimental geometry. Several earlier studies indicate that through post-transcriptional modification, direct protonation, or coordination with Mg(2+), accumulation of positive charge near N7 of guanine can stabilize the experimental geometry. Interestingly, recent studies reveal significant variation in the position of putatively bound Mg(2+)...
May 12, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28504350/the-arfgap-protein-moglo3-regulates-the-development-and-pathogenicity-of-magnaporthe-oryzae
#18
Shengpei Zhang, Xiu Liu, Lianwei Li, Rui Yu, Jialiang He, Haifeng Zhang, Xiaobo Zheng, Ping Wang, Zhengguang Zhang
The ADP ribosylation factor (Arf) and the coat protein complex I (COPI) are both involved in vesicle transport. Together with GTPase-activating proteins (ArfGAPs) and guanine exchange factors (ArfGEFs) that regulate the activity of Arf, they govern vesicle formation, COPI trafficking, and the maintenance of the Golgi complex. In an ongoing effort to study the role of membrane trafficking in pathogenesis of the rice blast fungus Magnaporthe oryzae, we identified MoGlo3 as an ArfGAP protein that is homologous to Glo3p of the budding yeast Saccharomyces cerevisiae...
May 15, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28501405/short-communication-nutrient-consumption-patterns-of-lactobacillus-acidophilus-klds-1-0738-in-controlled-ph-batch-fermentations
#19
Xuepeng Lv, Gefei Liu, Xiaomei Sun, Hongyu Chen, Jiahui Sun, Zhen Feng
This work focused on elucidating the nutrient consumption patterns of Lactobacillus acidophilus to guide the design of media for high-cell-density culture. We investigated the nutrient consumption patterns of L. acidophilus KLDS 1.0738 in chemically defined media in controlled pH batch fermentations. The most abundantly consumed amino acids, vitamins, ions, and purines and pyrimidines were Glu and Gly, pyridoxine and nicotinamide, K(+) and PO4(3-), and guanine and uracil, respectively. The highest consumption rates for amino acids, vitamins, ions, and purines and pyrimidines were Asp and Arg, folic acid and pyridoxine, Fe(2+) and Mn(2+), and uracil and thymine, respectively...
May 10, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28501212/a-selective-and-sensitive-fluorescent-probe-for-the-determination-of-hsa-and-trypsin
#20
Shanshan Huang, Fangfang Li, Caiyun Liao, Baozhan Zheng, Juan Du, Dan Xiao
A simple fluorescent probe HBI-GR based on the combination of the fluorophore (p-HBI) in green fluorescent protein (GFP) and Guanine riboside (GR) for HSA was successfully synthesized. HBI-GR showed an obvious fluorescence enhancement toward HSA without interference from other proteins, amino acids, anions and commonly existing metal ions. HBI-GR exhibited high sensitivity towards HSA with a good linear relationship between the fluorescence intensity of HBI-GR and HSA concentration from 0 to 0.06mgmL(-1). The limit of detection, based on a signal-to-noise ratio of 3, was 15...
August 1, 2017: Talanta
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