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https://www.readbyqxmd.com/read/29149687/pyrrolidinyl-pna-polypyrrole-silver-nanofoam-electrode-as-a-novel-label-free-electrochemical-mirna-21-biosensor
#1
Tawatchai Kangkamano, Apon Numnuam, Warakorn Limbut, Proespichaya Kanatharana, Tirayut Vilaivan, Panote Thavarungkul
A label-free electrochemical miRNA biosensor was developed based on a pyrrolidinyl peptide nucleic acid (acpcPNA)/polypyrrole (PPy)/silver nanofoam (AgNF) modified electrode. The AgNF was electrodeposited as redox indicator on a gold electrode, which was then functionalized with an electropolymerized layer of PPy, a conducting polymer, to immobilize the PNA probes. The fabrication process was investigated by electrochemical impedance spectroscopy. The biosensor was used to detect miRNA-21, a biomarker abnormally expressed in most cancers...
November 6, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29147003/real-time-wash-free-detection-of-unlabeled-pna-dna-hybridization-using-discrete-fet-sensor
#2
Matti Kaisti, Anssi Kerko, Eero Aarikka, Petri Saviranta, Zhanna Boeva, Tero Soukka, Ari Lehmusvuori
We demonstrate an electrochemical sensor for detection of unlabeled single-stranded DNA using peptide nucleic acid (PNA) probes coupled to the field-effect transistor (FET) gate. The label-free detection relies on the intrinsic charge of the DNA backbone. Similar detection schemes have mainly concentrated on sensitivity improvement with an emphasis on new sensor structures. Our approach focuses on using an extended-gate that separates the FET and the sensing electrode yielding a simple and mass fabricable device...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29144399/dna-g-wire-formation-using-an-artificial-peptide-is-controlled-by-protease-activity
#3
Kenji Usui, Arisa Okada, Shungo Sakashita, Masayuki Shimooka, Takaaki Tsuruoka, Shu-Ichi Nakano, Daisuke Miyoshi, Tsukasa Mashima, Masato Katahira, Yoshio Hamada
The development of a switching system for guanine nanowire (G-wire) formation by external signals is important for nanobiotechnological applications. Here, we demonstrate a DNA nanostructural switch (G-wire <--> particles) using a designed peptide and a protease. The peptide consists of a PNA sequence for inducing DNA to form DNA-PNA hybrid G-quadruplex structures, and a protease substrate sequence acting as a switching module that is dependent on the activity of a particular protease. Micro-scale analyses via TEM and AFM showed that G-rich DNA alone forms G-wires in the presence of Ca(2+), and that the peptide disrupted this formation, resulting in the formation of particles...
November 16, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29143694/cryo-scanning-electron-microscopy-sem-and-scanning-transmission-electron-microscopy-stem-in-sem-for-bio-and-organo-mineral-interface-characterization-in-the-environment
#4
Guillaume Wille, Jennifer Hellal, Patrick Ollivier, Annie Richard, Agnes Burel, Louis Jolly, Marc Crampon, Caroline Michel
Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy)...
November 16, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/29143031/acid-base-machines-electrical-work-from-neutralization-reactions
#5
Gilberto Lima, William G Morais, Wellington J A S Gomes, Fritz Huguenin
We have developed an electrochemical system that performs electrical work due to changes in alkaline ion and proton activities associated with acidic solution neutralization. This system can be used to treat wastewater, contributing to sustainable growth. The system includes an electrochemical machine that operates between an acidic and a basic reservoir to produce work in cycles comprising four stages: two isothermal ionic insertion/de-insertion steps and two steps involving acid and base injection. On the basis of the mixing free energy associated with the reaction free energy, we have developed the thermodynamic formalism by considering reversible electrochemical processes to determine the maximum work performed by this acid-base machine and the efficiency...
November 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29138026/hybrid-dna-i-motif-aminoethylprolyl-pna-pc5-enhance-the-stability-of-dna-dc5-i-motif-structure
#6
Chandrasekhar Reddy Gade, Nagendra K Sharma
This report describes the synthesis of C-rich sequence, cytosine pentamer, of aep-PNA and its biophysical studies for the formation of hybrid DNA:aep-PNAi-motif structure with DNA cytosine pentamer (dC5) under acidic pH conditions. Herein, the CD/UV/NMR/ESI-Mass studies strongly support the formation of stable hybrid DNA i-motif structure with aep-PNA even near acidic conditions. Hence aep-PNA C-rich sequence cytosine could be considered as potential DNA i-motif stabilizing agents in vivo conditions.
November 3, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/29137905/emergency-department-chest-radiography-for-children-with-asthma-exacerbation-is-infrequently-associated-with-change-of-management
#7
Evan H Allie, Henry E Dingle, William N Johnson, Jeffrey R Birnbaum, Melissa A Hilmes, Sudha P Singh, Donald H Arnold
BACKGROUND: Acute asthma exacerbations (AAE) account for many Pediatric Emergency Department (PED) visits. Chest radiography (CXR) is often performed in these patients to identify practice-changing findings such as pneumonia (PNA). Limited knowledge exists to balance the cost and radiation dose of CXR with expected yield of clinically meaningful information. OBJECTIVE: To determine in children with AAE with CXR, whether patient characteristics are associated with radiographic PNA; and significant practice change by initiation of antibiotic...
October 6, 2017: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/29137122/peptide-nucleic-acid-based-biosensors-for-cancer-diagnosis
#8
REVIEW
Roberta D'Agata, Maria Chiara Giuffrida, Giuseppe Spoto
The monitoring of DNA and RNA biomarkers freely circulating in the blood constitutes the basis of innovative cancer detection methods based on liquid biopsy. Such methods are expected to provide new opportunities for a better understanding of cancer disease at the molecular level, thus contributing to improved patient outcomes. Advanced biosensors can advance possibilities for cancer-related nucleic acid biomarkers detection. In this context, peptide nucleic acids (PNAs) play an important role in the fabrication of highly sensitive biosensors...
November 11, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29134205/towards-the-electrochemical-diagnostic-of-influenza-virus-development-of-a-graphene-au-hybrid-nanocomposite-modified-influenza-virus-biosensor-based-on-neuraminidase-activity
#9
Ülkü Anik, Yudum Tepeli, Maher Sayhi, Jihene Nsiri, Mohamed Fethi Diouani
An effective electrochemical influenza A biosensor based on a graphene-gold (Au) hybrid nanocomposite modified Au-screen printed electrode has been developed. The working principle of the developed biosensor relies on the measurement of neuraminidase (N) activity. After the optimization of experimental parameters like the effect of bovine serum albumin addition and immobilization times of fetuin A and PNA lectin, the analytical characteristics of the influenza A biosensor were investigated. As a result, a linear range between 10(-8) U mL(-1) and 10(-1) U mL(-1) was found with a relative standard deviation value of 3...
November 14, 2017: Analyst
https://www.readbyqxmd.com/read/29120457/management-of-neonatal-spontaneous-intestinal-perforation-by-peritoneal-needle-aspiration
#10
M Gébus, J-L Michel, S Samperiz, L Harper, J-L Alessandri, D Ramful
OBJECTIVE: To describe conservative management of spontaneous intestinal perforation (SIP) in preterm infants using peritoneal needle aspiration (PNA). STUDY DESIGN: Monocentric retrospective review of SIP cases treated primarily by PNA between 1999 and 2015 (n=31). RESULTS: Mean gestational age was 29.2±2.4 weeks and birthweight 1149±428 g. SIP occurred at 3.7±2.2 days of life. PNA achieved definitive treatment in 18 patients (60%) with a mean of 1...
November 9, 2017: Journal of Perinatology: Official Journal of the California Perinatal Association
https://www.readbyqxmd.com/read/29116759/selective-binding-to-mrna-duplex-regions-by-chemically-modified-pnas-stimulates-ribosomal-frameshifting
#11
Ru Ying Puah, Huan Jia, Manikantha Maraswami, Desiree-Faye Kaixin Toh, Rya Ero, Lixia Yang, Kiran M Patil, Alan Ann Lerk Ong, Manchugondanahalli S Krishna, Ruimin Sun, Cailing Tong, Mei Huang, Xin Chen, Teck-Peng Loh, Yonggui Gao, Ding Xiang Liu, Gang Chen
Minus-one programmed ribosomal frameshifting (-1 PRF) allows the precise maintenance of the ratio between viral proteins, and is involved in the regulation of the half-lives of cellular mRNAs. Minus-one ribosomal frameshifting (-1 RF) is activated by several stimulatory elements such as a heptameric slippery sequence (X XXY YYZ) and an mRNA secondary structure (hairpin or pseudoknot) that is positioned 2-8 nucleotides downstream from the slippery site. Upon -1 RF, the ribosomal reading frame is shifted from the normal zero frame to the -1 frame with the heptameric slippery sequence decoded as XXX YYY Z instead of X XXY YYZ...
November 8, 2017: Biochemistry
https://www.readbyqxmd.com/read/29112146/peptide-nucleic-acid-based-molecular-authentication-for-identification-of-four-medicinal-paeonia-species-using-melting-array-analysis-of-the-internal-transcribed-spacer-2-region
#12
Wook Jin Kim, Sungyu Yang, Goya Choi, Byeong Cheol Moon
Accurate taxonomic identification of plant materials in herbal medicines is important for product quality control. The genus Paeonia (Saxifragales) is the source of the herbal preparations Paeoniae Radix (Paeoniae Radix Alba and Paeoniae Radix Rubra) and Moutan Radicis Cotex. However, confusion has arisen regarding their contents due to linguistic and taxonomic ambiguities, similar morphologies and different definitions of Paeoniae Radix in the Korean and Chinese national pharmacopoeias, leading to the distribution of adulterated products...
November 7, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29111370/synthesis-and-optical-properties-of-pyrrolidinyl-peptide-nucleic-acid-bearing-a-base-discriminating-fluorescence-nucleobase-8-pyrene-1-yl-ethynyladenine
#13
Duangrat Nim-Anussornkul, Tirayut Vilaivan
A combination of fluorophore and nucleobase through a π-conjugated rigid linker integrates the base pairing and the fluorescence change into a single event. Such base discriminating fluorophore can change its fluorescence as a direct response to the base pairing event and therefore have advantages over tethered labels or base surrogates lacking the hydrogen-bonding ability. 8-(Pyrene-1-yl)ethynyl-adenine (A(PyE)) has been extensively used as fluorescence labels in DNA and LNA, but it showed little discrimination between different nucleobases...
October 13, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/29110361/hairy-cell-leukemia-2018-update-on-diagnosis-risk-stratification-and-treatment
#14
Xavier Troussard, Edouard Cornet
DISEASE OVERVIEW: Hairy cell leukemia (HCL) and HCL-like disorders, including HCL variant (HCL-V) and splenic diffuse red pulp lymphoma (SDRPL), are a very heterogeneous group of mature lymphoid B-cell disorders, characterized by the identification of hairy cells, a specific genetic profile, a different clinical course and the need for appropriate treatment. DIAGNOSIS: Diagnosis of HCL is based on morphological evidence of hairy cells, an HCL immunologic score of 3 or 4 based on the CD11C, CD103, CD123, and CD25 expression, the trephine biopsy which makes it possible to specify the degree of tumoral medullary infiltration and the presence of BRAF V600E somatic mutation...
December 2017: American Journal of Hematology
https://www.readbyqxmd.com/read/29104223/detection-of-rare-somatic-gnas-mutation-in-mccune-albright-syndrome-using-a-novel-peptide-nucleic-acid-probe-in-a-single-tube
#15
Fu-Sung Lo, Tai-Long Chen, Chiuan-Chian Chiou
McCune-Albright syndrome (MAS) is characterized by the triad of precocious puberty, café au lait pigmentation, and polyostotic fibrous dysplasia (FD) of bone, and is caused by post-zygotic somatic mutations-R201H or R201C-in the guanine nucleotide binding protein, alpha stimulating (GNAS) gene. In the present study, a novel peptide nucleic acid (PNA) probe with fluorescent labeling was designed to detect trace amounts of somatic mutant GNAS in a single tube reaction. The method was applied to screen GNAS mutations in six patients with MAS/FD...
November 1, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29094037/solid-phase-synthesis-of-difficult-purine-rich-pnas-through-selective-hmb-incorporation-application-to-the-total-synthesis-of-cell-penetrating-peptide-pnas
#16
Julien Tailhades, Hotake Takizawa, Michael J Gait, Don A Wellings, John D Wade, Yoshitsugu Aoki, Fazel Shabanpoor
Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2'-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29084421/hepatogenic-differentiation-capacity-of-human-wharton-s-jelly-mesenchymal-stem-cell-in-a-co-culturing-system-with-endothelial-cells-in-matrigel-collagen-scaffold-in-the-presence-of-fetal-liver-extract
#17
Zahra Khodabandeh, Zahra Vojdani, Tahereh Talaei-Khozani, Soghra Bahmanpour
Background: Human Wharton's jelly mesenchymal stem cells (HWJMSCs) isolated from medical waste product can be considered as an accessible source of cells in regenerative medicine. Stem cell-derived hepatocytes have poor function and need appropriate niche to reconstruct the liver structure. Therefore, we attempted to find a novel approach in differentiating HWJMSCs into functional hepatic cells using 3D culture conditions and liver extract that recapitulates vital stage in liver development...
October 31, 2017: International Journal of Stem Cells
https://www.readbyqxmd.com/read/29077023/design-of-tail-clamp-peptide-nucleic-acid-tethered-with-azobenzene-linker-for-sequence-specific-detection-of-homopurine-dna
#18
Shinjiro Sawada, Toshifumi Takao, Nobuo Kato, Kunihiro Kaihatsu
DNA carries genetic information in its sequence of bases. Synthetic oligonucleotides that can sequence-specifically recognize a target gene sequence are a useful tool for regulating gene expression or detecting target genes. Among the many synthetic oligonucleotides, tail-clamp peptide nucleic acid (TC-PNA) offers advantages since it has two homopyrimidine PNA strands connected via a flexible ethylene glycol-type linker that can recognize complementary homopurine sequences via Watson-Crick and Hoogsteen base pairings and form thermally-stable PNA/PNA/DNA triplex structures...
October 27, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29062633/comparative-effectiveness-of-needle-aponeurotomy-and-collagenase-injection-for-dupuytren-s-contracture-a-multicenter-study
#19
Chao Zhou, Steven E R Hovius, Adriana J Pieters, Harm P Slijper, Reinier Feitz, Ruud W Selles
BACKGROUND: Although the efficacy of collagenase clostridium histolyticum (CCH) injections has been demonstrated by randomized clinical trials, the relative effectiveness of CCH remains uncertain. Our aim was to compare the outcomes of CCH with those of percutaneous needle aponeurotomy (PNA) in daily clinical practice. METHODS: We analyzed data from patients undergoing PNA or CCH between 2011 and 2014 at 7 practice sites in the Netherlands. We examined the degree of improvement in contracture and adverse effects at 6-12 weeks after surgery or the last injection...
September 2017: Plastic and Reconstructive Surgery. Global Open
https://www.readbyqxmd.com/read/29055249/peptide-nucleic-acid-as-a-selective-recognition-element-for-electrochemical-determination-of-hg-2
#20
Agnieszka Bala, Łukasz Górski
A novel electrochemical PNA-based biosensor for the determination of Hg(2+) is described. The receptor layer, containing single strands of polythymine PNA (peptide nucleic acid), was formed at the surface of gold electrode. Due to the presence of thymine bases and peptide bonds, an interaction between Hg(2+) ion and receptor layer occurs. The influence of chain modification - PNA vs. DNA - and type of redox marker - anionic AQMS-Na (sodium salt of anthraquinone-2-sulfonic acid) and Fe(II/III) (potassium ferri/ferrocyanide) or cationic MB (methylene blue) and RuHex (hexaammineruthenium(III) chloride) - were studied...
October 12, 2017: Bioelectrochemistry
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