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Xiuli Chen, Hao Chen, Chunyan Lu, Chao Yang, Xiaoqi Yu, Kun Li, Yongmei Xie
In this report, the design of two novel nitrogen mustard-based DNA cross-linking agents with fluorophores incorporated into the structure (TN-A and TN-B) is disclosed. The results indicate that TN-A and TN-B can serve directly as both reporting and imaging agents for flow cytometry and gel electrophoresis without the necessity of another fluorescent tagging agents. TN-A and TN-B both selectively locate in the mitochondria and exhibit good antitumor activity. Notably, TN-A is the first DNA crosslinking agent with near infrared fluorescence emission properties...
December 1, 2016: Talanta
Jiamian Wang, Jie Song, Xiuyun Wang, Shuo Wu, Yanqiu Zhao, Pinchen Luo, Changgong Meng
A label-free ratiometric fluorescence aptasensor has been developed for the rapid and sensitive detection of cocaine in complex biofluids. The fluorescent aptasensor is composed of a non-labeled GC-38 cocaine aptamer which serves as a basic sensing unit and two fluorophores, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) and SYBR Green I (SGI) which serves as a signal reporter and a build-in reference, respectively. The detection principle is based on a specific cocaine mediated ATMND displacement reaction and the corresponding change in the fluorescence ratio of ATMND to SGI...
December 1, 2016: Talanta
Allegra T Aron, Morten O Loehr, Jana Bogena, Christopher J Chang
Iron is essential for sustaining life, as its ability to cycle between multiple oxidation states is critical for catalyzing chemical transformations in biological systems. However, without proper regulation, this same redox capacity can trigger oxidative stress events that contribute to aging along with diseases ranging from cancer to cardiovascular and neurodegenerative disorders. Despite its importance, methods for monitoring biological iron bound weakly to cellular ligands-the labile iron pool-to generate a response that preserves spatial and temporal information remain limited, owing to the potent fluorescence quenching ability of iron...
October 21, 2016: Journal of the American Chemical Society
Tao Peng, Howard C Hang
Over the past years, fluorescent proteins (e.g., green fluorescent proteins) have been widely utilized to visualize recombinant protein expression and localization in live cells. Although powerful, fluorescent protein tags are limited by their relatively large sizes and potential perturbation to protein function. Alternatively, site-specific labeling of proteins with small-molecule organic fluorophores using bioorthogonal chemistry may provide a more precise and less perturbing method. This approach involves site-specific incorporation of unnatural amino acids (UAAs) into proteins via genetic code expansion, followed by bioorthogonal chemical labeling with small organic fluorophores in living cells...
October 21, 2016: Journal of the American Chemical Society
Satoshi Habuchi, Takuya Yamamoto, Yasuyuki Tezuka
We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis...
September 26, 2016: Journal of Visualized Experiments: JoVE
Benoîte Bourdin, Emilie Segura, Marie-Philippe Tétreault, Sylvie Lesage, Lucie Parent
Inherited or de novo mutations in cation-selective channels may lead to sudden cardiac death. Alteration in the plasma membrane trafficking of these multi-spanning transmembrane proteins, with or without change in channel gating, is often postulated to contribute significantly in this process. It has thus become critical to develop a method to quantify the change of the relative cell surface expression of cardiac ion channels on a large scale. Herein, a detailed protocol is provided to determine the relative total and cell surface expression of cardiac L-type calcium channels CaV1...
September 28, 2016: Journal of Visualized Experiments: JoVE
Hao Zhu, Jiangli Fan, Huiying Mu, Tao Zhu, Zhen Zhang, Jianjun Du, Xiaojun Peng
Polarity-sensitive fluorescent probes are powerful chemical tools for studying biomolecular structures and activities both in vitro and in vivo. However, the lack of "off-on" polarity-sensing probes has limited the accurate monitoring of biological processes that involve an increase in local hydrophilicity. Here, we design and synthesize a series of "off-on" polarity-sensitive fluorescent probes BP series consisting of the difluoroboron dippyomethene (BODIPY) fluorophore connected to a quaternary ammonium moiety via different carbon linkers...
October 21, 2016: Scientific Reports
Bianka Swiderska, Sylwia Kedracka-Krok, Barbara Plytycz
The data described are related to the article "Lysenin family proteins in earthworm coelomocytes - comparative approach" (B. Swiderska, S. Kedracka-Krok, T. Panz, A.J. Morgan, A. Falniowski, P.Grzmil, B. Plytycz, 2016) [1]. Lysenin family proteins were identified based on unique peptides sequenced by tandem mass spectrometry coupled with liquid chromatography (LC-MS/MS) in lumbricid earthworms Eisenia andrei and E. fetida, the latter with or without the MUG-like fluorophore. Lysenin and lysenin-related protein 2 (LRP-2, fetidin) were identified in all 9 investigated specimens of Eisenia sp...
December 2016: Data in Brief
Sahishna Phaniraj, Zhe Gao, Digamber Rane, Blake R Peterson
The endoplasmic reticulum (ER) of eukaryotic cells plays critical roles in the processing of secreted and transmembrane proteins. Defects in these functions are associated with a wide range of pathologies. To image this organelle, cells are often treated with fluorescent ER-Tracker dyes. Although these compounds are selective, existing red fluorescent probes of the ER are costly glibenclamide derivatives that inhibit ER-associated sulphonylurea receptors. To provide simpler and more cost-effective red fluorescent probes of the ER, we synthesized amino analogues of the fluorophore resorufin...
December 2016: Dyes and Pigments: An International Journal
Bobby A Tajudeen, Zachary D Taylor, James Garritano, Harrison Cheng, Aidan Pearigen, Adria J Sherman, Fernando Palma-Diaz, Pratik Mishra, Siddharth Bhargava, Julianna Pesce, Irene Kim, Christine Sebastian, Ali Razfar, Asael Papour, Oscar Stafsudd, Warren Grundfest, Maie St John
BACKGROUND: Head and neck squamous cell carcinomas (HNSCCs) are debilitating diseases for which a patient's prognosis depends heavily on complete tumor resection. Currently, the surgeon's fingers determine the location of tissue margins. This study evaluated the diagnostic utility of a novel imaging modality, dynamic optical contrast imaging (DOCI), in the detection of HNSCC. This system generates contrast by illuminating the tissue with pulsed light and detecting variations in endogenous fluorophore lifetimes...
October 20, 2016: Cancer
Chao-Chen Lin, Hsin-Fang Hsu, Peter Jomo Walla
The fusion of two opposing membranes is essential in biological functions such as fertilization, viral entry, membrane trafficking and synaptic transmission. Before the membrane bilayers are fully connected, at some stage a hemifusion intermediate-when the outer leaflets are merged but not the inner leaflets-is formed. However, the position of hemifusion in the energy landscape and the duration of it vary and have not been fully mapped out. To date, there has not been a way to differentiate lipid mixing of the two leaflets directly in a single experiment...
October 20, 2016: Journal of Physical Chemistry. B
Britta Unruhe-Knauf, Shirley K Knauer
The chromosomal passenger complex (CPC) is a key regulator of cell division. Its proper localization during the different phases of mitosis and cytokinesis is crucial for the exertion of its various functions. HDACi treatment has been demonstrated to disturb the centromeric localization of the CPC in tumor cells, thus leading to severe mitotic defects often followed by apoptosis. In this chapter, we describe how HDACi-induced changes of the CPC localization can be analyzed by indirect immunofluorescence using CPC-specific primary and fluorophore-coupled secondary antibodies followed by confocal microscopy...
2017: Methods in Molecular Biology
Michael Poteser, Gerd Leitinger, Elisabeth Pritz, Dieter Platzer, Irene Frischauf, Christoph Romanin, Klaus Groschner
Nanometer-spaced appositions between endoplasmic reticulum and plasma membrane (ER-PM junctions) stabilized by membrane-joining protein complexes are critically involved in cellular Ca(2+)-handling and lipid trafficking. ER-PM junctional architecture and plasticity associated with inter-membrane communication are as yet barely understood. Here, we introduce a method to precisely characterize ER-PM junction morphology and dynamics with high temporal resolution and minimal disturbance of junctional intermembrane communication...
October 19, 2016: Scientific Reports
Yohei Okada, Masae Sugai, Kazuhiro Chiba
Fluorophores with emission wavelengths that shift depending on their hydrogen-bonding microenvironment in water would be fascinating tools for the study of biological events. Herein, we describe the design and synthesis of a series of water-soluble solvatochromic fluorophores, 2,5-bis(oligoethylene glycol)oxybenzaldehydes (8-11) and 2,5-bis(oligoethylene glycol)oxy-1,4-dibenzaldehydes (14-17), based on a push-pull strategy. Unlike typical examples in this class of fluorophores, the fluorescence properties of these compounds are independent of solvent polarity and become fluorescent upon intermolecular hydrogen-bonding, exhibiting high quantum yields (up to φ = 0...
October 18, 2016: Journal of Organic Chemistry
Boran Lee, Byung Gyu Park, Wansang Cho, Ho Yong Lee, András Olasz, Chun-Hsing Chen, Seung Bum Park, Dongwhan Lee
A series of air-stable boron complexes 1-5 were prepared by using N-aryl iminopyrrolide ligands. Designed as minimalist structural mimics of the privileged BODIPY motif, these new BOIMPY (BOron complexes of IMinoPYrrolide ligands) fluorophores feature low molecular symmetry that promotes emission from CT-type excited states with large Stokes shifts and little self-quenching. Through comparative studies on the homologous set of compounds 1-4, we have confirmed that a delicate interplay between conformational twisting and donor-acceptor interaction dictates the mechanism of de-excitation, which responds sensitively to solvent polarity as well as protonation states...
October 18, 2016: Chemistry: a European Journal
L Brulikova, Y Okorochenkova, J Hlavac
An efficient methodology using the Fukuyama-Mitsunobu reaction was successfully applied to prepare various Rhodamine B-based amides with the locked possibility to form a lactam ring. The procedure was developed for solid-phase synthesis, which can be advantageously applied to the synthesis of chemical libraries in a combinatorial fashion. A series of derivatives including aliphatic as well as aromatic rhodamine amides alkylated via a reaction with various alcohols were synthesized, and their spectral properties were investigated...
October 18, 2016: Organic & Biomolecular Chemistry
Xiaohong Zhou, Yuren Jiang, Xiongjie Zhao, Dong Guo
Photoactivatable fluorophores have become an important technique for the high spatiotemporal resolution of biological imaging. Here, we developed a novel photoactivatable probe (PHBT), which is based on 2-(2-hydroxyphenyl)benzothiazole (HBT), a small organic fluorophore known for its classic luminescence mechanism through excited-state intramolecular proton transfer (ESIPT) with the keto form and the enol form. After photocleavage, PHBT released a ratiometric fluorophore HBT, which showed dual emission bands with more than 73-fold fluorescence enhancement at 512 nm in buffer and more than 69-fold enhancement at 452 nm in bovine serum...
October 12, 2016: Sensors
Fawzia A Ibrahim, Amina M Elbrashy, Jenny Jeehan M Nasr, Mostafa M Badr El-Dien
Three different spectrophotometric and two spectrofluorimetric methods have been developed and validated for the determination of vincamine (VN) and naftidrofuryl oxalate (NF) in tablets. The spectrophotometric methods depend on charge transfer complex formation between each of VN and NF with 7,7,8,8-tetracyano-quinodimethane (TCNQ), 2,6-dichloroquinone-4-chloroimide (DCQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at 843, 580 and 588 nm, respectively. The spectrofluorimetric methods are based on the formation of charge transfer complex between each of the two drugs and TCNQ, with measurement of the fluorophore formed at 312/375 and 284/612 nm, respectively, or with DDQ at 400/475 and 284/396 nm, respectively...
October 18, 2016: Luminescence: the Journal of Biological and Chemical Luminescence
Elena W Y Hsieh, Joseph D Hernandez
PURPOSE OF REVIEW: This review gives an overview of the systems-immunology single-cell proteomic and transcriptomic approaches that can be applied to study primary immunodeficiency. It also introduces recent advances in multiparameter tissue imaging, which allows extensive immune phenotyping in disease-affected tissue. RECENT FINDINGS: Mass cytometry is a variation of flow cytometry that uses rare earth metal isotopes instead of fluorophores as tags bound to antibodies, allowing simultaneous measurement of over 40 parameters per single-cell...
October 5, 2016: Current Opinion in Allergy and Clinical Immunology
Christopher Batchelor-McAuley, Christopher A Little, Stanislav V Sokolov, Enno Kätelhön, Giorgia Zampardi, Richard G Compton
The lipid soluble fluorophore Nile Red (9-diethylamino-5-benzo[α]phenoxazinone) is used to fluorescently and electrochemically label an organic-in-water emulsion, where the organic phase is an ionic liquid [P6,6,6,14][FAP]/toluene mixture. The optical detection of the individual droplets is enabled facilitating the in-situ tracking and sizing of the suspended particles (average diameter = 530 nm, interquartile range = 180 nm). Through the use of a combined thin-layer optical/electrochemical cell, the irreversible accumulation of the droplets at an optically opaque carbon fibre electrode (diameter ~ 7...
October 17, 2016: Analytical Chemistry
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