Read by QxMD icon Read

Forster resonance energy transfer

Haseong Kim, Gui Hwan Han, Yaoyao Fu, Jongsik Gam, Seung Goo Lee
Recent improvements in Förster resonance energy transfer (FRET) sensors have enabled their use to detect various small molecules including ions and amino acids. However, the innate weak signal intensity of FRET sensors is a major challenge that prevents their application in various fields and makes the use of expensive, high-end fluorometers necessary. Previously, we built a cost-effective, high-performance FRET analyzer that can specifically measure the ratio of two emission wavelength bands (530 and 480 nm) to achieve high detection sensitivity...
October 1, 2016: Journal of Visualized Experiments: JoVE
Qing Wang, Yongkui Zhang, Hui Li
Octyl gallate (OG) is an internationally recognized antioxidant that demonstrates selective and sensitive fluorescent property. The fluorescence of OG can be selectively enhanced in the presence of human serum albumin (HSA) and bovine serum albumin (BSA). The specific structures of HSA and BSA provided the basic conditions for fluorescence enhancement. OG yielded approximately 49- and 11-fold increments in emission intensity in the presence of HSA and BSA at a molar ratio of 1:1, respectively. The lifetimes of HSA and BSA correspondingly decreased...
March 15, 2017: Food Chemistry
Robert F Gahl, Pallavi Dwivedi, Nico Tjandra
The most critical step in the initiation of apoptosis is the activation of the Bcl-2 family of proteins to oligomerize and permeabilize the outer-mitochondrial membrane (OMM). As this step results in the irreversible release of factors that enhance cellular degradation, it is the point of no return in programmed cell death and would be an ideal therapeutic target. However, the arrangement of the Bcl-2 proteins in the OMM during permeabilization still remains unknown. It is also unclear whether the Bcl-2 protein, Bid, directly participates in the formation of the oligomers in live cells, even though it is cleaved and translocates to the OMM at the initiation of apoptosis...
October 20, 2016: Cell Death & Disease
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
François E Dufrasne, Catherine Lombard, Patrick Goubau, Jean Ruelle
BST-2 or tetherin is a host cell restriction factor that prevents the budding of enveloped viruses at the cell surface, thus impairing the viral spread. Several countermeasures to evade this antiviral factor have been positively selected in retroviruses: the human immunodeficiency virus type 2 (HIV-2) relies on the envelope glycoprotein (Env) to overcome BST-2 restriction. The Env gp36 ectodomain seems involved in this anti-tetherin activity, however residues and regions interacting with BST-2 are not clearly defined...
October 14, 2016: Viruses
Christine Koehler, Paul F Sauter, Mirella Wawryszyn, Gemma Estrada Girona, Kapil Gupta, Jonathan J M Landry, Markus Hsi-Yang Fritz, Ksenija Radic, Jan-Erik Hoffmann, Zhuo A Chen, Juan Zou, Piau Siong Tan, Bence Galik, Sini Junttila, Peggy Stolt-Bergner, Giancarlo Pruneri, Attila Gyenesei, Carsten Schultz, Moritz Bosse Biskup, Hueseyin Besir, Vladimir Benes, Juri Rappsilber, Martin Jechlinger, Jan O Korbel, Imre Berger, Stefan Braese, Edward A Lemke
We present a baculovirus-based protein engineering method that enables site-specific introduction of unique functionalities in a eukaryotic protein complex recombinantly produced in insect cells. We demonstrate the versatility of this efficient and robust protein production platform, 'MultiBacTAG', (i) for the fluorescent labeling of target proteins and biologics using click chemistries, (ii) for glycoengineering of antibodies, and (iii) for structure-function studies of novel eukaryotic complexes using single-molecule Förster resonance energy transfer as well as site-specific crosslinking strategies...
October 17, 2016: Nature Methods
Ana V Ferreira, Ilana Perelshtein, Nina Perkas, Aharon Gedanken, Joana Cunha, Artur Cavaco-Paulo
Chronic wound fluids have elevated concentration of human neutrophil elastase (HNE) which can be used as inflammation/infection marker. Our goal is to develop functional materials for fast diagnosis of wound inflammation/infection by using HNE as a specific marker. For that, fluorogenic peptides with a HNE-specific cleavage sequence were incorporated into traditional textile dressings, to allow real-time detection of the wound status. Two different fluorogenic approaches were studied in terms of intensity of the signal generated upon HNE addition: a fluorophore 7-amino-4-trifluormethylcoumarin (AFC) conjugated to a HNE-specific peptide and two fluorophore/quencher pairs (FAM/Dabcyl and EDANS/Dabcyl) coupled to a similar peptide as a Förster resonance energy transfer (FRET) strategy...
October 15, 2016: Applied Microbiology and Biotechnology
I Velázquez-López, E León-Cruz, J P Pardo, A Sosa-Peinado, M González-Andrade
Eight new fluorescent biosensors of human calmodulin (hCaM) using Alexa Fluor(®) 350, 488, 532, and 555 dyes were constructed. These biosensors are thermodynamically stable, functional, and highly sensitive to ligands of the CaM. They resolve the problem of CaM ligands with similar spectroscopic properties to the intrinsic and extrinsic fluorophores of other biosensors previously reported. Additionally, they can be used in studies of protein-protein interaction through Förster resonance energy transfer (FRET)...
October 12, 2016: Analytical Biochemistry
Chan-I Chung, Ryoji Makino, Yuki Ohmuro-Matsuyama, Hiroshi Ueda
Fluorescence-based biosensor probes, especially those based on Förster resonance energy transfer (FRET) between fluorescent protein (FP) variants, are widely used to monitor various biological phenomena, often detecting ligand-induced association of the receptor domains. While antibodies are fertile sources of specific receptors for various biomolecules, their potential has not been fully exploited. In this study, we used a fluorescent probe comprising FP-fused antibody variable region fragments to detect a bone metabolism biomarker, osteocalcin (BGP), by using fluorescence spectrometry/microscopy...
October 12, 2016: Journal of Bioscience and Bioengineering
Luke J Higgins, Cristian A Marocico, Vasilios D Karanikolas, Alan P Bell, John J Gough, Graham P Murphy, Peter J Parbrook, A Louise Bradley
A range of seven different Ag plasmonic arrays formed using nanostructures of varying shape, size and gap were fabricated using helium-ion lithography (HIL) on an InGaN/GaN quantum well (QW) substrate. The influence of the array geometry on plasmon-enhanced Förster resonance energy transfer (FRET) from a single InGaN QW to a ∼80 nm layer of CdSe/ZnS quantum dots (QDs) embedded in a poly(methyl methacrylate) (PMMA) matrix is investigated. It is shown that the energy transfer efficiency is strongly dependent on the array properties and an efficiency of ∼51% is observed for a nanoring array...
October 14, 2016: Nanoscale
Gayan Senavirathne, Santosh K Mahto, Jeungphill Hanne, Daniel O'Brian, Richard Fishel
Wrapping of genomic DNA into nucleosomes poses thermodynamic and kinetic barriers to biological processes such as replication, transcription, repair and recombination. Previous biochemical studies have demonstrated that in the presence of adenosine triphosphate (ATP) the human RAD51 (HsRAD51) recombinase can form a nucleoprotein filament (NPF) on double-stranded DNA (dsDNA) that is capable of unwrapping the nucleosomal DNA from the histone octamer (HO). Here, we have used single molecule Förster Resonance Energy Transfer (smFRET) to examine the real time nucleosome dynamics in the presence of the HsRAD51 NPF...
October 13, 2016: Nucleic Acids Research
Sebastián A Díaz, Florencia Gillanders, Kimihiro Susumo, Eunkeu Oh, Igor L Medintz, Thomas M Jovin
Photoswitchable probes are of great utility in fluorescence microscopy, permitting numerous determinations, including molecular localization for super-resolution, based on their modifiable emission intensity and spectra. We have coated a blue (425 nm) emitting quantum dot (QD) with a diheteroarylethene photochrome (PCf), the closed form isomer of which has absorption and emission maxima at 440 and 520-530 nm, respectively, and thus functions as a fluorescent acceptor for the QD donor in Förster resonance energy transfer (FRET)...
October 9, 2016: Chemistry: a European Journal
W Bruinsma, M Aprelia, I García-Santisteban, J Kool, Y J Xu, R H Medema
When cells in G2 phase are challenged with DNA damage, several key mitotic regulators such as Cdk1/Cyclin B, Aurora A and Plk1 are inhibited to prevent entry into mitosis. Here we have studied how inhibition of Plk1 is established after DNA damage. Using a Förster resonance energy transfer (FRET)-based biosensor for Plk1 activity, we show that inhibition of Plk1 after DNA damage occurs with relatively slow kinetics and is entirely dependent on loss of Plk1-T210 phosphorylation. As T210 is phosphorylated by the kinase Aurora A in conjunction with its co-factor Bora, we investigated how they are affected by DNA damage...
October 10, 2016: Oncogene
Xinrong Guo, Fangying Wu, Yongnian Ni, Serge Kokot
A strong red fluorescent nanocomposite, consisting of graphite-like carbon nitride nanosheets (g-C3N4 NSs) and serum albumin-capped Au nanoclusters (AuNCs), was synthesized. Dopamine (DA) can quench the red fluorescence of the nanocomposite, based on the Forster resonance energy transfer (FRET) mechanism. In this quenching process, the energy is transferred from the fluorescent g-C3N4 NSs-AuNCs to the oxidized DA quinine molecules (DA is easily oxidated to form DA quinine in air). The red fluorescence emission at 420 nm decreases dramatically and the quenching ratio (F0 - F)/F0 is linearly related to the concentration of DA in the range of 0...
October 26, 2016: Analytica Chimica Acta
Bhaswati Sengupta, Arusha Acharyya, Pratik Sen
The ps-μs dynamics of domain-III of human serum albumin (HSA) has been investigated using a new fluorescent marker selectively labeled to the Tyr-411 residue. The location of the marker has been confirmed using Förster resonance energy transfer (FRET) study. Steady state, time-resolved and single molecular level fluorescence techniques have been employed to understand the dynamics within the domain-III of HSA. It is found that solvent reorganization dynamics in domain-III is 1.7 times faster than that in domain-I...
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
Sonja Schmid, Markus Götz, Thorsten Hugel
We present a simple and robust technique for extracting kinetic rate models and thermodynamic quantities from single-molecule time traces. Single-molecule analysis of complex kinetic sequences (SMACKS) is a maximum-likelihood approach that resolves all statistically relevant rates and also their uncertainties. This is achieved by optimizing one global kinetic model based on the complete data set while allowing for experimental variations between individual trajectories. In contrast to dwell-time analysis, which is the current standard method, SMACKS includes every experimental data point, not only dwell times...
October 4, 2016: Biophysical Journal
Nicholas E Larkey, Lulu Zhang, Shan S Lansing, Victoria Tran, Victoria L Seewaldt, Sean M Burrows
Many studies have found that over- or under-expression of biomolecules called microRNAs (miRNA) regulates several diseases. Biosensors are in need to visually identify the relative expression level of miRNA to determine the direction these miRNA change in cells and tissues. Our established reporter+probe miRNA biosensor design requires that miRNA outcompete and displace the reporter from the probe. Once displaced, the reporter folds into a hairpin structure to force together a pair of Förster Resonance Energy Transfer (FRET) dyes...
September 22, 2016: Analyst
Hui Wang, Songjin Zhang, Xiumei Tian, Chufeng Liu, Lei Zhang, Wenyong Hu, Yuanzhi Shao, Li Li
Nanoprobes for combined optical and magnetic resonance imaging have tremendous potential in early cancer diagnosis. Gold nanoparticles (AuNPs) co-doped with Gd2O3 mesoporous silica nanocomposite (Au/Gd@MCM-41) can produce pronounced contrast enhancement for T1 weighted image in magnetic resonance imaging (MRI). Here, we show the remarkably high sensitivity of Au/Gd@MCM-41 to the human poorly differentiated nasopharyngeal carcinoma (NPC) cell line (CNE-2) using fluorescence lifetime imaging (FLIM). The upconversion luminescences from CNE-2 and the normal nasopharyngeal (NP) cells (NP69) after uptake of Au/Gd@MCM-41 show the characteristic of two-photon-induced-radiative recombination of the AuNPs...
October 3, 2016: Scientific Reports
Nicole C Robb, Aartjan J W Te Velthuis, Ralph Wieneke, Robert Tampé, Thorben Cordes, Ervin Fodor, Achillefs N Kapanidis
Influenza viruses have a segmented viral RNA (vRNA) genome, which is replicated by the viral RNA-dependent RNA polymerase (RNAP). Replication initiates on the vRNA 3' terminus, producing a complementary RNA (cRNA) intermediate, which serves as a template for the synthesis of new vRNA. RNAP structures show the 3' terminus of the vRNA template in a pre-initiation state, bound on the surface of the RNAP rather than in the active site; no information is available on 3' cRNA binding. Here, we have used single-molecule Förster resonance energy transfer (smFRET) to probe the viral RNA conformations that occur during RNAP binding and initial replication...
September 30, 2016: Nucleic Acids Research
Victoria Steffen, Julia Otten, Susann Engelmann, Andreas Radek, Michael Limberg, Bernd W Koenig, Stephan Noack, Wolfgang Wiechert, Martina Pohl
Background: The fast development of microbial production strains for basic and fine chemicals is increasingly carried out in small scale cultivation systems to allow for higher throughput. Such parallelized systems create a need for new rapid online detection systems to quantify the respective target compound. In this regard, biosensors, especially genetically encoded Förster resonance energy transfer (FRET)-based biosensors, offer tremendous opportunities. As a proof-of-concept, we have created a toolbox of FRET-based biosensors for the ratiometric determination of l-lysine in fermentation broth...
2016: Sensors
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"