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Tesfaye Tolessa, Zhi-Qiang Tan, Jing-Fu Liu
Antimony (Sb) is a toxic element which causes different health problems including cardiac problems and lung cancer in humans, and its levels in surface water can be noticeably increased to 100 μg/L typically in the proximity of anthropogenic sources. Thus, besides instrumental techniques, it is of great significance to develop a simple, sensitive and selective analytical method for direct analysis of Sb(III) at trace level without the need of any expensive and/or complicated instrumentations and sample preparation processes...
April 3, 2018: Analytica Chimica Acta
Jasmina Topcagic, Rebecca Feldman, Anatole Ghazalpour, Jeffrey Swensen, Zoran Gatalica, Semir Vranic
Olfactory neuroblastoma (ONB) is a rare, locally aggressive, malignant neoplasm originating in the olfactory epithelium in the nasal vault. The recurrence rate of ONB remains high and there are no specific treatment guidelines for recurrent/metastatic ONBs. This study retrospectively evaluated 23 ONB samples profiled at Caris Life Sciences (Phoenix, Arizona) using DNA sequencing (Sanger/NGS [Illumina], n = 15) and gene fusions (Archer FusionPlex, n = 6), whole genome RNA microarray (HumanHT-12 v4 beadChip, Illumina, n = 4), gene copy number assays (chromogenic and fluorescent in situ hybridization), and immunohistochemistry...
2018: PloS One
Rasha Abd Alraouf Neama, Manal A Habib, Sahira A Ali, Ali H Al-Khafaji, Mohammed F Alqanbar
BACKGROUND: The human epidermal growth factor receptor 2(HER2) proto-oncogene is overexpressed or amplified in approximately 15%-25% of invasive breast cancers. Approximately 35% of HER2-amplified breast cancers have coamplification of the topoisomerase II-alpha (TOP2A) gene encoding an enzyme that is a major target of anthracyclines. Hence, the determination of genetic alteration (amplification or deletion) of both genes is considered as an important predictive factor that determines the response of breast cancer patients to treatment...
October 2017: Indian Journal of Pathology & Microbiology
Vitaly Grigorenko, Igor Uporov, Maya Rubtsova, Irina Andreeva, Dmitrii Shcherbinin, Alexander Veselovsky, Oksana Serova, Maria Ulyashova, Igor Ishtubaev, Alexey Egorov
Highly mutable β-lactamases are responsible for the ability of Gram-negative bacteria to resist β-lactam antibiotics. Using site-directed mutagenesis technique, we have produced in vitro a number of recombinant analogs of naturally occurring TEM-type β-lactamases, bearing the secondary substitution Q39K and key mutations related to the extended-spectrum (E104K, R164S) and inhibitor-resistant (M69V) β-lactamases. The mutation Q39K alone was found to be neutral and hardly affected the catalytic properties of β-lactamases...
January 2018: FEBS Open Bio
James Ziai, Houston N Gilbert, Oded Foreman, Jeffrey Eastham-Anderson, Felix Chu, Mahrukh Huseni, Jeong M Kim
The prevalence of cytotoxic tumor infiltrating lymphocytes (TILs) has demonstrated prognostic value in multiple tumor types. In particular, CD8 counts (in combination with CD3 and CD45RO) have been shown to be superior to traditional UICC staging in colon cancer patients and higher total CD8 counts have been associated with better survival in breast cancer patients. However, immune infiltrate heterogeneity can lead to potentially significant misrepresentations of marker prevalence in routine histologic sections...
2018: PloS One
Vinod Kumar, Hemlata Rana, G Raviraju, Arvind K Gupta
Since the first use of chemical warfare agents (CWA) (1915) to the recent attacks in Syria (2017) on mankind, there have been many incidents where CWA have claimed thousands of lives and left many more contaminated. In order to provide the appropriate and immediate medical counter measure to the victims, the exact classification of these chemical agents within few minutes on the field itself using a rapid and simple detection technique is extremely important to save the lives of the effected people. This has motivated all of us to explore the novel strategies/detection systems that can be field deployable with better selectivity and greater sensitivity...
January 4, 2018: Analytical Chemistry
Maria G Khrenova, Alexander V Nemukhin
The transient absorption spectroscopy of hydrolysis of the chromogenic substrate nitrocefin by the L1 metallo-β-lactamase (MβL), a bacterial enzyme responsible for destruction of β-lactam antibiotics molecules, showed formation and decay of a plausible red-shifted reaction intermediate. We propose a mechanism of this important reaction consistent with the transient kinetic data. Quantum mechanics/molecular mechanics (QM/MM) simulations of the reaction pathway revealed occurrence of two reaction intermediates (I1, I2) between the enzyme-substrate (ES) and enzyme-product (EP) complexes...
January 3, 2018: Journal of Physical Chemistry. B
Gili Aviv, Ohad Gal-Mor
β-galactosidase assay has been established as one of the most widely used reporters and can be effectually exploited to study promoter activity of Salmonella and other pathogens under various conditions. This method includes a preliminary stage of fusing the target promoter to a promoter-less lacZ gene encoding for the enzyme β-galactosidase. Supplementation of the synthetic ONPG substrate results in the accumulation of a chromogenic product proportionally to the activity of the fused promoter. Here we demonstrate the usage of this reporter system to study the regulation of the Salmonella Type three secretion system effector gene sseL in S...
2018: Methods in Molecular Biology
Ruyue Fan, Xiangning Bai, Shanshan Fu, Yanmei Xu, Hui Sun, Hong Wang, Yanwen Xiong
Shiga toxin-producing Escherichia coli (STEC) are globally important food-borne pathogens. The isolation of non-O157 STEC is a significant public health challenge due to the dramatic diversity of their phenotypes and genotypes. In the present study, 476 non-O157 STEC strains representing 95 different O-serogroups were used to evaluate tellurite resistance and the performance of 12 different chromogenic agars. Of 476 strains, only 108 (22.7%) strains showed the minimal inhibitory concentration (MIC) values for potassium tellurite being higher than 4μg/ml, and 96 (20...
December 17, 2017: International Journal of Food Microbiology
Katie St Ledger, Annette Feussner, Uwe Kalina, Carsten Horn, Hubert J Metzner, Debra Bensen-Kennedy, Nicole Blackman, Alex Veldman, Anthony Stowers, Kenneth D Friedman
INTRODUCTION: AFSTYLA (antihemophilic factor [recombinant] single chain) is a novel B-domain truncated recombinant Factor VIII (rFVIII). For AFSTYLA, an approximate 50% discrepancy was observed between results of the one-stage (OS) and chromogenic substrate (ChS) FVIII activity AFSTYLA assays. An investigation was undertaken to test whether there is a linear relationship between ChS and OS assay results that would allow reliable clinical interpretation of results independent of the assay method used...
December 23, 2017: Journal of Thrombosis and Haemostasis: JTH
Suparna Paul, Pritam Ghosh, Samuzal Bhuyan, Subhra Kanti Mukhopadhyay, Priyabrata Banerjee
A dual-channel chromogenic and fluorogenic fused-aromatic-system-based chemoreceptor (2-(benzo[d]thiazol-2-yl)-1-((pyren-8-yl)methylene)hydrazine) (TyM) was designed for ditopic sensitivity towards heavy and transition metal ions (HTMs), such as Cu2+, in an aqueous medium and lethal CN- in a semi-aqueous medium. The chemoreceptor displayed proclivity towards the targeted analytes with a distinct optical response (yellow to colourless in the case of Cu2+ and yellow to bright red for CN-). TyM formed a 2 : 1 adduct with Cu2+ with a detection limit of 40 nM...
December 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Jian Sun, Jiahui Zhao, Lei Wang, Hongwei Li, Fan Yang, Xiurong Yang
Being an important model peroxidase, horseradish peroxidase (HRP) has been thoroughly understood, and the detection of HRP is not only directly related to peroxidase-triggered catalytic process, but also linked to the development of HRP-based enzyme-linked immunosorbent assay (ELISA). Herein, we have reported an unconventional fluorescent sensor for convenient assay of HRP activity based on the HRP-catalyzed specific conversion of p-phenylenediamine (PPD) into chromogenic PPDox with H2O2 as the oxidizing agent, accompanied with the fluorescence quenching effect on fluorescein...
December 20, 2017: ACS Sensors
Haq Nawaz, Weiguo Tian, JinMing Zhang, Ruonan Jia, Zhangyan Chen, Jun Zhang
Iron ions play a vital role in many biological processes, and their concentrations are responsible for human health. Therefore, it is essential to detect the concentrations of iron ions by a rapid, accurate, highly-selective and practical method. Herein, we have synthesized a cellulose-based fluorescent sensor (Phen-MDI-CA) for the highly-selective and rapid detection of Fe2+ ions, via chemically bonding 1,10-phenanthroline-5-amine (Phen) onto cellulose acetate (CA) using 4,4'-methylene diphenyl diisocyanate (MDI) as a crosslinker...
December 20, 2017: ACS Applied Materials & Interfaces
Ji-Hong Bong, Hyun-Woo Song, Tae-Hun Kim, Min-Jung Kang, Joachim Jose, Jae-Chul Pyun
In this study, a single-domain antibody against negative regulatory factor (anti-NEF scFv) was autodisplayed on the outer membrane of Escherichia coli and used to detect NEF in an immunoassay based on fluorescence-activated cell sorting, enzyme-linked immunosorbent assay, and surface plasmon resonance biosensors. Next, the autodisplayed single-domain antibody was oxidized to form disulfide bonds by using glutathione, and the change in NEF-binding activity of anti-NEF scFv was analyzed by fluorescence-activated cell sorting-based immunoassay, chromogenic immunoassay, and surface plasmon resonance biosensor...
December 8, 2017: Biosensors & Bioelectronics
Alejandra P Frasch, León A Bouvier, Florencia M Oppenheimer, Maria Aparecida Juliano, Luiz Juliano, Adriana K Carmona, Juan José Cazzulo, Gabriela T Niemirowicz
Metallocarboxypeptidases (MCPs) of the M32 family, while broadly distributed among prokaryotic organisms, have so far been only found in a few eukaryotes including trypanosomatids. Among these organisms are human and animal pathogens of medical relevance such as Trypanosoma brucei and Trypanosoma cruzi, the respective causative agents of sleeping sickness and Chagas disease. The M32 MCP orthologues found in these parasites share 72% protein sequence identity. They also present a cytosolic localization, a similar pattern of expression and a marked preference for Arg/Lys residues at P1'...
December 12, 2017: Molecular and Biochemical Parasitology
Dayang Zou, Simo Huang, Hong Lei, Zhan Yang, Yuxin Su, Xiaoming He, Qinghe Zhao, Yong Wang, Wei Liu, Liuyu Huang
The emergence of the plasmid-encoded colistin-resistance gene mcr-1 in Enterobacteriaceae represents a new threat to the treatment of infection in the clinical setting. A sensitive and rapid molecular method for detection of the mcr-1 gene in clinical isolates is needed to control the spread of this gene. In this study, we established a loop-mediated isothermal amplification (LAMP) assay for rapid detection of the mcr-1 gene. This assay was applied to cultured bacteria and spiked human stools. Real-time monitoring of turbidity and chromogenic visualization were used to assess the reaction results...
2017: Frontiers in Microbiology
Nilanjan Dey, Satadru Jha, Santanu Bhattacharya
Chromogenic probe with oxidized bis-indolyl scaffold has been synthesized for the detection of a nerve gas mimicking agent, DCNP (diethyl cyanophosphonate) at pH 8.0 in water. The mechanism of interaction was proposed as the release of cyanide ion through the indole group mediating the hydrolysis of phosphorous-hetero atom bond and, thereafter, the Michael addition of the liberated CN- ion to the electron deficient C[double bond, length as m-dash]C bond of the bis-indolyl moiety. The reaction featured a remarkable change in color from red to colorless at ambient condition...
December 13, 2017: Analyst
Yu Jiang, Guangping Zhang, Dong Yan, Hong Yang, Zuguang Ye, Tonghui Ma
Thrombotic diseases have become a global burden due to morbidity, mortality, and disability. Traditional Chinese medicine has been proven effective in removing blood stasis and promoting blood circulation, but the exact mechanisms remain unclear. Plasminogen activator inhibitor-1 (PAI-1) is a natural inhibitor of tissue-type and urokinase-type plasminogen activators. In this study, we screened four fractions of Resina Draconis (a traditional Chinese medicine) extract for PAI-1 inhibitory activity. Bioactivity-guided purification and chromogenic substrate-based assay led to the identification of loureirin B as the major PAI-1 inhibitor, with an IC50 value of 26...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
Tao Gao, Chaoli Mu, Hai Shi, Liu Shi, Xiaoxia Mao, Genxi Li
Using emerging nano-catalysts to investigate the activity of bio-catalysts (protein enzymes, catalytic RNAs, ect.) is increasingly receiving attention from material, analytical and biomedical scientists. Here, we have first fabricated a three-in-one nano-catalyst, the nitrilotriacetic acid (NTA)-modified magnetite nanoparticle (NTA-MNPs), to develop an integrated magneto-colorimetric (MagColor) assay for lipid kinase activity, so as to solve the inherent problems in lipid kinase assay. Based on three integrated functions of the NTA-MNPs (capture, magnetic separation and peroxidase activity), catalytic activity of lipid kinase is directly converted to colorimetric signals...
December 12, 2017: ACS Applied Materials & Interfaces
Salim Neselioglu, Merve Ergin, Ozcan Erel
A new kinetic and automated assay was developed to determine ceruloplasmin ferroxidase activity. Ferrous ions are turned into ferric ions via catalytic activity of the ferroxidase enzyme. Acetohydroxamic acid, a chromogen, forms a colored complex with ferric ions. This reaction was measured kinetically. Significant and strong correlations were obtained between the new acetohydroxamic method and the p-phenylenediamine oxidase (r = 0.988, p <0.001), o-dianisidine oxidase (r = 0.981, p <0.001), norfloxacine oxidase (r = 0...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
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