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Xing Yang, Feng Zhang, Yang Zhou, Yi-Yong Huang
We herein report an unprecedented addition reaction of pinacol gem-difluoroallylborates and imines enabled by a neighboring phenolic group in an N-protecting group under catalyst-free conditions, thus facilitating the construction of a wide range of racemic gem-difluorohomoallylamine derivatives. Based on the control experiments, a plausible transition state via the Zimmerman-Traxler model was proposed to elucidate the significance of the neighboring phenolic group, as well as the γ-selectivity of the boronate reagents...
April 25, 2018: Organic & Biomolecular Chemistry
Harita Gogri, Pranali Pitale, Manisha Madkaikar, Swati Kulkarni
BACKGROUND: Haemagglutination has been the gold standard for defining the blood group status. However, these tests depend upon the availability of specific and reliable antisera. Potent antisera for extended phenotyping are very costly, weakly reacting or available in limited stocks and unavailable for some blood group systems like Indian, Dombrock, Coltan, Diego etc. The Indian blood group system consists of two antithetical antigens, Ina and Inb . The Ina /Inb polymorphism arises from 252C > G missense mutation in the CD44 gene...
April 11, 2018: Transfusion and Apheresis Science
Ivan Sakharov
A covalent conjugate of horseradish apoperoxidase and amino-containing oligonucleotide was synthesized for the first time. Using the obtained conjugate as a capture reagent chemiluminescent microtiter plate-based assay for detection of 35-mer fragment of hepatitis B virus (HBV) DNA (proof-of-concept analyte) was developed. To detect the target DNA, a signaling system consisted of biotinylated reporter oligonucleotide and HRP-streptavidin conjugate was used. The high sensitivity of the assay was due to the enhanced chemiluminescence reaction, where 3-(10′-phenothiazinyl)propane-1-sulfonate/ N -morpholinopyridine pair was used as an enhancer...
April 23, 2018: Sensors
Roberto Fernandez-Maestre
Ion mobility spectrometry (IMS) is an analytical technique used for fast and sensitive detection of illegal substances in customs and airports, diagnosis of diseases through detection of metabolites in breath, fundamental studies in physics and chemistry, space exploration and many more applications. IMS separates ions in the gas-phase drifting under an electric field according to their size to charge ratio. IMS disadvantages are false positives that delay transportation, compromise patient's health and other negative issues when IMS is used for detection...
April 24, 2018: Journal of Mass Spectrometry: JMS
Alfred Tuley, Walter Fast
Covalent enzyme inhibitors are widely applied as biochemical tools and therapeutic agents. As a complement to categorization of these inhibitors by reactive group or modification site, we present a categorization by mechanism, which highlights common advantages and disadvantages inherent to each approach. Established categories for reversible and irreversible covalent inhibition are reviewed with representative examples given for each class, including covalent reversible inhibitors, slow substrates, residue-specific reagents, affinity labels (classical, quiescent, and photoaffinity), and mechanism-based inactivators...
April 24, 2018: Biochemistry
Birgit Spiess, Nicole Naumann, Norbert Galuschek, Sébastien Rinaldetti, Ute Kossak-Roth, Irina Tarnopolscaia, Elena Felde, Alice Fabarius, Wolf-Karsten Hofmann, Susanne Saußele, Wolfgang Seifarth
Quantitative real-time polymerase chain reaction (qRT-PCR) is state of the art in molecular monitoring of minimal residual disease in chronic myeloid leukemia (CML). In this context, maintenance of assay fidelity and detection of technical inaccuracy are crucial. Beside multiple common negative controls for the clinical sample preparations, quality control charts (QCC) are a common validation tool to sustain high process quality by continuously recording of qRT-PCR control parameters. Here, we report on establishment and benefit of QCC in qRT-PCR-based CML diagnostics...
2018: PloS One
Aida I Vientós-Plotts, Ellen N Behrend, Elizabeth G Welles, Dennis J Chew, Philippe R Gaillard, Jessica N Busler, Hollie P Lee
OBJECTIVE To evaluate effects of blood contamination on dipstick results, specific gravity (SG), and urine protein-to-urine creatinine ratio (UPCR) for urine samples from dogs and cats. SAMPLE Urine samples collected from 279 dogs and 120 cats. PROCEDURES Urine pools were made for each species (dogs [n = 60] and cats [30]). Blood was added to an aliquot of a pool, and serial dilutions were prepared with the remaining urine. Color and dipstick variables were recorded, and SG and UPCR were measured. For cats, 1 set of pools was used; for dogs, 2 sets were used...
May 2018: American Journal of Veterinary Research
Prashant V Ghorpade, Dattatray Appassa Pethsangave, Surajit Some, Ganapati S Shankarling
The mildly acidic and oxidative nature of graphene oxide, with its large surface area available for catalytic activity, has been explored in aromatic nuclear bromination chemistry for the first time. The versatile catalytic activity of graphene oxide (GO) has been used to selectively and rapidly brominate anilines and phenols in water. The best results were obtained at ambient temperatures using molecular bromine in a protocol promoted by oxidative bromination catalyzed by GO; these transformations proceeded with 100% atom economy with respect to bromine, and high selectivities for the tribromoanilines and -phenols...
April 24, 2018: Journal of Organic Chemistry
Yuji Iwata, Tsukasa Iida, Toshihiro Matsunami, Yu Yamada, Kei-Ichiro Mishiba, Takumi Ogawa, Tetsuya Kurata, Nozomu Koizumi
The unfolded protein response (UPR) occurs when protein folding and maturation are disturbed in the endoplasmic reticulum (ER). During the UPR, a number of genes including those encoding ER-resident molecular chaperones are induced. In Arabidopsis, BiP3 has been used as a UPR marker gene whose expression is strongly induced in response to ER stress. In this study, we mutagenized Arabidopsis plants expressing β-glucuronidase (GUS) gene under the control of BiP3 promoter and isolated a mutant that exhibits strong GUS activity without treatment with ER stress inducers...
April 24, 2018: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Argha Bhattacharjee, Hiromu Hosoya, Hideaki Ikeda, Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N'-bis(trimethylsilyl)-4,4'-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was compatible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phenylhydroxylamine (7a) as a readily available and safety phenylnitrene source from nitrobenzene, and double-deoxygenation, giving N,N-bis(trimerhylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP)...
April 24, 2018: Chemistry: a European Journal
David M Coppola, Burton Slotnick
In the course of our ongoing studies of odor-cued taste avoidance (OCTA) to measure olfactory capabilities in animals, we observed that mice could rapidly learn to use the vapor of the classical bitterant quinine hydrochloride to avoid contact with the tastant. Here we expand on this observation to determine which among several compounds generally classed as bitter could be detected at a distance. Since mice were initially naïve we were able to assess whether the vapors of the bitter compounds tested were innately aversive as are their tastes...
April 23, 2018: Chemical Senses
Thomas R Carey, Kristen L Cotner, Brian Li, Lydia L Sohn
Advancements in microfluidic technologies have led to the development of many new tools for both the characterization and sorting of single cells without the need for exogenous labels. Label-free microfluidics reduce the preparation time, reagents needed, and cost of conventional methods based on fluorescent or magnetic labels. Furthermore, these devices enable analysis of cell properties such as mechanical phenotype and dielectric parameters that cannot be characterized with traditional labels. Some of the most promising technologies for current and future development toward label-free, single-cell analysis and sorting include electronic sensors such as Coulter counters and electrical impedance cytometry; deformation analysis using optical traps and deformation cytometry; hydrodynamic sorting such as deterministic lateral displacement, inertial focusing, and microvortex trapping; and acoustic sorting using traveling or standing surface acoustic waves...
April 24, 2018: Wiley Interdisciplinary Reviews. Nanomedicine and Nanobiotechnology
Christian P Nixon, Stephanie L Krohto, Joseph D Sweeney
BACKGROUND: Patient samples showing a positive indirect antiglobulin test are further tested to identify alloantibody specificity using a panel of phenotypically characterized group O reagent red blood cells (RBCs). Donor RBCs phenotypically negative for the antibody specificity are then serologically crossmatched using an antiglobulin reagent. This latter test is performed to identify any incompatibility due to the presence of undetected minor blood group antibodies and considered an important step in patient safety...
April 24, 2018: Transfusion
Jixing Li, Wenxia Cong, Zeng Gao, Jinlong Zhang, Huameng Yang, Gaoxi Jiang
A new approach for highly regioselective iodination of azobenzenes with alkyl iodide as the iodinating reagent enabled by Rh-catalyzed oxidative C-H activation has been developed. By changing the oxidant, various mono- and di-iodinated azobenzenes were smoothly obtained in moderate to excellent yields, respectively. The preliminary mechanistic study reveals that the reaction process might undergo electrophilic substitution of the directed ortho metalated five-membered rhodacycle compound by an iodine cationic species generated in situ from alkyl iodide and oxidant...
April 24, 2018: Organic & Biomolecular Chemistry
Andrei V Bogdanov, Ilyuza F Zaripova, Alexandra D Voloshina, Anastasia S Sapunova, Natalia V Kulik, Julia K Voronina, Vladimir F Mironov
A high-yield synthesis of some novel isatin-3-acylhydrazones on the base of 5-ethylisatin derivatives and Girard's reagent T is described. Antimicrobial activity preliminary SAR study of both 1-benzylated isatins and water-soluble hydrazones was established. The most active against Staphylococcus aureus and Bacillus cereus are ammonium salts bearing 3,4-dichloro- or 4-CF3 substituents in benzyl fragment. This article is protected by copyright. All rights reserved.
April 23, 2018: Chemistry & Biodiversity
Samia M El-Gizawy, Noha N Atia, Noha M Hosny
A rapid, simple, selective and precise fluorimetric method was developed and validated for determination of a selective xanthine oxidase inhibitor; febuxostat (FBX) in pharmaceutical formulations and in human plasma. The proposed method is based on quenching effect of FBX on the fluorescence intensity of terbium (Tb3+ ) through fluorescence resonance energy transfer (FRET) from Tb3+ to FBX. The formed complex was measured at λex. 320 nm/λem. 490 nm against a reagent blank. Fluorescence intensity of Tb3+ was diminished when FBX was added...
April 24, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
Zhouxi Lei, Chunhua Zhou, Xiaoyu Ji, Gang Wei, Yuechun Huang, Wenxia Yu, Yingyi Luo, Yue Qiu
In this study, we applied transcriptome and UHPLC-MS technologies to investigate the flavonoids and their biosynthesis- and accumulation-related genes in Dendrobium catenatum from three different locations. Eight flavonoid glycosides were identified using standard references or previously isolated substances with MS data analysis. The total flavonoid contents were determined by reagents, and all the data were analyzed. In total, 23139 unigenes were obtained using the Dendrobium catenatum genome data. Of these, 10398 were annotated in the Gene Ontology (GO) database, 4203 were annotated in the KEGG database, and 10917 were annotated in the EuKaryotic Orthologous Groups (KOG) database...
April 23, 2018: Scientific Reports
Joanna I Lachowicz, Miriam Crespo-Alonso, Claudia Caltagirone, Giancarla Alberti, Raffaela Biesuz, James O Orton, Valeria M Nurchi
This paper presents an easy, fast and economic synthesis of chelating agents for medical, environmental and analytical applications, and the evaluation of the stability of their complexes with Fe3+ and Al3+ . Complex formation equilibria with Cu2+ and Zn2+ metal ions were also studied to evaluate if the chelating agents can perturb the homeostatic equilibria of these essential metal ions. Effective chelating agents for metal ions, in addition to their well-known medical uses, find an increasing number of applications in environmental remediation, agricultural applications (supplying essential elements in an easily available form), and in analytical chemistry as colorimetric reagents...
April 16, 2018: Journal of Trace Elements in Medicine and Biology
Hailee H Rau, Nathan S Werner
A general procedure for the stereocontrolled synthesis of (E)-stilbene derivatives by palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of (E)-2-phenylethenylboronic acid pinacol ester with aryl bromides was investigated. (E)-2-Phenylethenylboronic acid pinacol ester was prepared by 9-BBN-catalyzed hydroboration of phenylacetylene with pinacolborane. This reagent undergoes facile palladium-catalyzed cross-coupling with a diverse set of aryl bromides to provide the corresponding (E)-stilbene derivatives in moderate to good yield...
April 3, 2018: Bioorganic & Medicinal Chemistry Letters
Mukti Ram Paudel, Mukesh Babu Chand, Basant Pant, Bijaya Pant
BACKGROUND: The medicinal orchid Dendrobium moniliforme contains water-soluble polysaccharides, phenanthrenes, bibenzyl derivatives, and polyphenol compounds. This study explored the antioxidant and cytotoxic activities of D. moniliforme extracts and detected their bioactive compounds. METHODS: Plant material was collected from the Daman of Makawanpur district in central Nepal. Plant extracts were prepared from stems using hexane, chloroform, acetone, ethanol and methanol...
April 23, 2018: BMC Complementary and Alternative Medicine
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