keyword
MENU ▼
Read by QxMD icon Read
search

fluorescence lifetime imaging microscopy

keyword
https://www.readbyqxmd.com/read/27927752/vesicular-ptdins-3-4-5-p3-and-rab-7-are-key-effectors-of-zygote-nuclear-membrane-fusion
#1
Marta G Lete, Richard D Byrne, Alicia Alonso, Dominic Poccia, Banafshé Larijani
Regulation of nuclear envelope (NE) dynamics is an important example of the universal phenomena of membrane fusion. The signalling molecules involved in nuclear membrane fusion may also be conserved in the formation of both pronuclear and zygote NEs in the fertilised egg. Here, we determine that Class I PI3-kinases are needed for in vitro nuclear envelope formation. We show that, in vivo, PtdIns(3,4,5)P3 is transiently located in vesicles around the male pronucleus at the time of nuclear envelope formation and around male and female pronuclei prior to membrane fusion...
December 7, 2016: Journal of Cell Science
https://www.readbyqxmd.com/read/27917506/comparative-in-vitro-toxicity-assessment-of-perfluorinated-carboxylic-acids
#2
Cecon T Mahapatra, Nur P Damayanti, Samuel C Guffey, Jennifer S Serafin, Joseph Irudayaraj, Maria S Sepúlveda
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic fluorinated compounds that are highly bioaccumulative and persistent organic pollutants. Perfluorooctanoic acid (PFOA), an eight-carbon chain perfluorinated carboxylic acid, was used heavily for the production of fluoropolymers, but concerns have led to its replacement by shorter carbon chain homologues such as perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA). However, limited toxicity data exist for these substitutes. We evaluated the toxicity of PFOA, PFHxA and PFBA on a zebrafish liver cell line and investigated the effects of exposure on cell metabolism...
December 5, 2016: Journal of Applied Toxicology: JAT
https://www.readbyqxmd.com/read/27914984/recapitulating-the-human-tumor-microenvironment-colon-tumor-derived-extracellular-matrix-promotes-angiogenesis-and-tumor-cell-growth
#3
Mónica Romero-López, Andrew L Trinh, Agua Sobrino, Michaela M S Hatch, Mark T Keating, Cristhian Fimbres, David E Lewis, Paul D Gershon, Elliot L Botvinick, Michelle Digman, John S Lowengrub, Christopher C W Hughes
Extracellular matrix (ECM) is an essential and dynamic component of all tissues and directly affects cellular behavior by providing both mechanical and biochemical signaling cues. Changes in ECM can alter tissue homeostasis, potentially leading to promotion of cellular transformation and the generation of tumors. Therefore, understanding ECM compositional changes during cancer progression is vital to the development of targeted treatments. Previous efforts to reproduce the native 3D cellular microenvironment have utilized protein gels and scaffolds that incompletely recapitulate the complexity of native tissues...
November 24, 2016: Biomaterials
https://www.readbyqxmd.com/read/27911813/spatiotemporal-imaging-of-small-gtpases-activity-in-live-cells
#4
Stephanie Voss, Dennis M Krüger, Oliver Koch, Yao-Wen Wu
Ras-like small GTPases function as molecular switches and regulate diverse cellular events. To examine the dynamics of signaling requires spatiotemporal visualization of their activity in the cell. Current small GTPase sensors rely on specific effector domains that are available for only a small number of GTPases and compete for endogenous regulator/effector binding. Here, we describe versatile conformational sensors for GTPase activity (COSGAs) based on the conserved GTPase fold. Conformational changes upon GDP/GTP exchange were directly observed in solution, on beads, and in live cells by Förster resonance energy transfer (FRET)...
November 29, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27910894/calcium-ions-function-as-a-booster-of-chromosome-condensation
#5
Rinyaporn Phengchat, Hideaki Takata, Kenichi Morii, Noriko Inada, Hideji Murakoshi, Susumu Uchiyama, Kiichi Fukui
Chromosome condensation is essential for the faithful transmission of genetic information to daughter cells during cell division. The depletion of chromosome scaffold proteins does not prevent chromosome condensation despite structural defects. This suggests that other factors contribute to condensation. Here we investigated the contribution of divalent cations, particularly Ca(2+), to chromosome condensation in vitro and in vivo. Ca(2+) depletion caused defects in proper mitotic progression, particularly in chromosome condensation after the breakdown of the nuclear envelope...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27904946/chlorophyll-fluorescence-lifetime-imaging-provides-new-insight-into-the-chlorosis-induced-by-plant-virus-infection
#6
Rong Lei, Hongshan Jiang, Fan Hu, Jin Yan, Shuifang Zhu
Leaf chlorosis induced by plant virus infection has a short fluorescence lifetime, which reflects damaged photosynthetic complexes and degraded chloroplasts. Plant viruses often induce chlorosis and necrosis, which are intimately related to photosynthetic functions. Chlorophyll fluorescence lifetime measurement is a valuable noninvasive tool for analyzing photosynthetic processes and is a sensitive indicator of the environment surrounding the fluorescent molecules. In this study, our central goal was to explore the effect of viral infection on photosynthesis by employing chlorophyll fluorescence lifetime imaging (FLIM), steady-state fluorescence, non-photochemical quenching (NPQ), transmission electron microscopy (TEM), and pigment analysis...
November 30, 2016: Plant Cell Reports
https://www.readbyqxmd.com/read/27904898/a-dual-photoluminescence-enhancement-system-stabilization-of-a-water-soluble-aiee-fluorogen-using-silver-nanowire
#7
Ying-Chen Chiang, Chun-Ta Huang, Wei Hsin Wang, Cheng-Chung Chang
This manuscript describes the preparation of water soluble aggregation-induced emission enhancement (AIEE)-based fluorescent organic nanoparticles (FONs). The fluorescence diversity of the FONs was investigated in the presence of silver nanowires. We observed that the emission of the FONs can be enhanced by mixing with the nanowires, which is believed to originate from resonance between the emission of the FONs and the surface plasmon resonances of the metal surface. That is, the AIEE phenomenon was promoted according to the metal-enhanced fluorescence (MEF) mechanism that can be used to build up a novel double emission enhancement (DEE) platform and to extend the range of AIEE applications...
December 1, 2016: Faraday Discussions
https://www.readbyqxmd.com/read/27896951/hydrogen-peroxide-modulates-energy-metabolism-and-oxidative-stress-in-cultures-of-permanent-human-m%C3%A3-ller-cells-mio-m1
#8
Sven Peters, Max Griebsch, Matthias Klemm, Jens Haueisen, Martin Hammer
In this study the influence of hydrogen peroxide (H2 O2 ) on the redox state, NADH protein binding, and mitochondrial membrane potential in Müller cells is investigated. Cultures of permanent human Müller cells MIO-M1 were exposed to H2 O2 in 75 µM and 150 µM concentration for two hours. Fluorescence emission spectra and lifetimes were measured by two-photon microscopy (excitation wavelength: 740 nm) at the mitochondria which were identified in the microscopic images by their fluorescence properties (spectra and intensity)...
November 29, 2016: Journal of Biophotonics
https://www.readbyqxmd.com/read/27872481/imaging-cellular-dynamics-with-spectral-relaxation-imaging-microscopy-distinct-spectral-dynamics-in-golgi-membranes-of-living-cells
#9
Alireza Lajevardipour, James W M Chon, Amitabha Chattopadhyay, Andrew H A Clayton
Spectral relaxation from fluorescent probes is a useful technique for determining the dynamics of condensed phases. To this end, we have developed a method based on wide-field spectral fluorescence lifetime imaging microscopy to extract spectral relaxation correlation times of fluorescent probes in living cells. We show that measurement of the phase and modulation of fluorescence from two wavelengths permit the identification and determination of excited state lifetimes and spectral relaxation correlation times at a single modulation frequency...
November 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27869857/increasing-the-collection-efficiency-of-time-correlated-single-photon-counting-with-single-photon-avalanche-diodes-using-immersion-lenses
#10
Charles Pichette, Andrea Giudice, Simon Thibault, Yves Bérubé-Lauzière
Single-photon avalanche diodes (SPADs) achieving high timing resolution (≈20-50  ps) developed for time-correlated single-photon counting (TCSPC) generally have very small photosensitive areas (25-100 μm in diameter). This limits the achievable photon counting rate and signal-to-noise ratio and may lead to long counting times. This is detrimental in applications requiring several measurements, such as fluorescence lifetime imaging (FLIM) microscopy, which requires scanning, and time-domain diffuse optical tomography (TD-DOT)...
November 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/27864764/fret-flim-for-visualizing-and-quantifying-protein-interactions-in-live-plant-cells
#11
Alejandra Freire Rios, Tatyana Radoeva, Bert De Rybel, Dolf Weijers, Jan Willem Borst
Proteins are the workhorses that control most biological processes in living cells. Although proteins can accomplish their functions independently, the vast majority of functions require proteins to interact with other proteins or biomacromolecules. Protein interactions can be investigated through biochemical assays such as co-immunoprecipitation (co-IP) or Western blot analysis, but such assays lack spatial information. Here we describe a well-developed imaging method, Förster resonance energy transfer (FRET) analyzed by fluorescence lifetime imaging microscopy (FLIM), that can be used to visualize protein interactions with both spatial and temporal resolution in live cells...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27859594/glutamate-transporter-associated-anion-channels-adjust-intracellular-chloride-concentrations-during-glial-maturation
#12
Verena Untiet, Peter Kovermann, Niklas J Gerkau, Thomas Gensch, Christine R Rose, Christoph Fahlke
Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl(-) ]int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na(+) -K(+) -2Cl(-) cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl(-) ]int to values that vary upon changes in expression levels or activity of these channels...
November 18, 2016: Glia
https://www.readbyqxmd.com/read/27857286/high-speed-time-resolved-laser-scanning-microscopy-using-the-line-to-pixel-referencing-method
#13
Jiheun Ryu, Jayul Kim, Hyunjun Kim, Jae-Heon Jeong, Hak-Jun Lee, Hongki Yoo, Dae-Gab Gweon
Fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to visualize photophysical characteristics of biological targets. However, conventional FLIM methods have some limitations that restrict obtaining high-precision images in real time. Here, we propose a high-speed time-resolved laser-scanning microscopy by incorporating a novel line-to-pixel referencing method into the previously suggested analog mean-delay (AMD) method. The AMD method dramatically enhances the photon accumulation speed for achieving the certain precision compared to the time-correlated single-photon counting (TCSPC) method while maintaining high photon efficiency...
November 10, 2016: Applied Optics
https://www.readbyqxmd.com/read/27857076/3d-visualization-of-additive-occlusion-and-tunable-full-spectrum-fluorescence-in-calcite
#14
David C Green, Johannes Ihli, Paul D Thornton, Mark A Holden, Bartosz Marzec, Yi-Yeoun Kim, Alex N Kulak, Mark A Levenstein, Chiu Tang, Christophe Lynch, Stephen E D Webb, Christopher J Tynan, Fiona C Meldrum
From biomineralization to synthesis, organic additives provide an effective means of controlling crystallization processes. There is growing evidence that these additives are often occluded within the crystal lattice. This promises an elegant means of creating nanocomposites and tuning physical properties. Here we use the incorporation of sulfonated fluorescent dyes to gain new understanding of additive occlusion in calcite (CaCO3), and to link morphological changes to occlusion mechanisms. We demonstrate that these additives are incorporated within specific zones, as defined by the growth conditions, and show how occlusion can govern changes in crystal shape...
November 18, 2016: Nature Communications
https://www.readbyqxmd.com/read/27856908/characterization-of-a-dynamic-metabolon-producing-the-defense-compound-dhurrin-in-sorghum
#15
Tomas Laursen, Jonas Borch, Camilla Knudsen, Krutika Bavishi, Federico Torta, Helle Juel Martens, Daniele Silvestro, Nikos S Hatzakis, Markus R Wenk, Timothy R Dafforn, Carl Erik Olsen, Mohammed Saddik Motawia, Björn Hamberger, Birger Lindberg Møller, Jean-Etienne Bassard
Metabolic highways may be orchestrated by the assembly of sequential enzymes into protein complexes, or metabolons, to facilitate efficient channeling of intermediates and to prevent undesired metabolic cross-talk while maintaining metabolic flexibility. Here we report the isolation of the dynamic metabolon that catalyzes the formation of the cyanogenic glucoside dhurrin, a defense compound produced in sorghum plants. The metabolon was reconstituted in liposomes, which demonstrated the importance of membrane surface charge and the presence of the glucosyltransferase for metabolic channeling...
November 18, 2016: Science
https://www.readbyqxmd.com/read/27847940/heterogeneity-of-crowded-cellular-fluids-on-the-meso-and-nanoscale
#16
Olivia Stiehl, Matthias Weiss
Cellular fluids are complex media that are crowded with macromolecules and membrane-enclosed organelles on several length scales. Many studies have shown that crowding can significantly alter transport and reaction kinetics in biological but also in bio-mimetic fluids. Yet, experimental insights on how well bio-mimetic fluids can capture the complexity of cellular fluids are virtually missing. Therefore, we have combined fluorescence correlation spectroscopy (FCS) and fluorescence lifetime imaging microscopy (FLIM) to compare the spatial heterogeneities of biological and simple bio-mimetic crowded fluids...
November 16, 2016: Soft Matter
https://www.readbyqxmd.com/read/27819078/pyrrolic-molecular-rotors-acting-as-viscosity-sensors-with-high-fluorescence-contrast
#17
Seung-Chul Lee, Jeongyun Heo, Jong-Wan Ryu, Chang-Lyoul Lee, Sehoon Kim, Joon-Sung Tae, Byung-Ohk Rhee, Sang-Wook Kim, O-Pil Kwon
New pyrrolic viscosity sensors exhibit one order of magnitude higher fluorescence contrast compared to that of the conventional phenolic analogues due to the viscosity-sensitive rotation of the asymmetric pyrrole group and successfully demonstrate mapping of intracellular viscosity by fluorescence lifetime imaging microscopy.
November 17, 2016: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/27816622/electrospun-poly-l-lactide-scaffold-for-the-controlled-and-targeted-delivery-of-a-synthetically-obtained-diclofenac-prodrug-to-treat-actinic-keratosis
#18
Germano Piccirillo, Brigida Bochicchio, Antonietta Pepe, Katja Schenke-Layland, Svenja Hinderer
: Actinic Keratosis' (AKs) are small skin lesions that are related to a prolonged sun-damage, which can develop into invasive squamous cell carcinoma (SCC) when left untreated. Effective, specific and well tolerable therapies to cure AKs are still of great interest. Diclofenac (DCF) is the current gold standard for the local treatment of AKs in terms of costs, effectiveness, side effects and tolerability. In this work, an electrospun polylactic acid (PLA) scaffold loaded with a synthetic DCF prodrug was developed and characterized...
November 2, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/27782585/a-wide-field-tcspc-flim-system-based-on-an-mcp-pmt-with-a-delay-line-anode
#19
Wolfgang Becker, Liisa M Hirvonen, James Milnes, Thomas Conneely, Ottmar Jagutzki, Holger Netz, Stefan Smietana, Klaus Suhling
We report on the implementation of a wide-field time-correlated single photon counting (TCSPC) method for fluorescence lifetime imaging (FLIM). It is based on a 40 mm diameter crossed delay line anode detector, where the readout is performed by three standard TCSPC boards. Excitation is performed by a picosecond diode laser with 50 MHz repetition rate. The photon arrival timing is obtained directly from the microchannel plates, with an instrumental response of ∼190 to 230 ps full width at half maximum depending on the position on the photocathode...
September 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27781216/dynamic-viscosity-mapping-of-the-oxidation-of-squalene-aerosol-particles
#20
Athanasios Athanasiadis, Clare Fitzgerald, Nicholas M Davidson, Chiara Giorio, Stanley W Botchway, Andrew D Ward, Markus Kalberer, Francis D Pope, Marina K Kuimova
Organic aerosols (OAs) play important roles in multiple atmospheric processes, including climate change, and can impact human health. The physico-chemical properties of OAs are important for all these processes and can evolve through reactions with various atmospheric components, including oxidants. The dynamic nature of these reactions makes it challenging to obtain a true representation of their composition and surface chemistry. Here we investigate the microscopic viscosity of the model OA composed of squalene, undergoing chemical aging...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
keyword
keyword
77714
1
2
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"