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fluorescence lifetime imaging microscopy

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https://www.readbyqxmd.com/read/29222855/non-euclidean-phasor-analysis-for-quantification-of-oxidative-stress-in-ex-vivo-human-skin-exposed-to-sun-filters-using-fluorescence-lifetime-imaging-microscopy
#1
Sam Osseiran, Elisabeth M Roider, Hequn Wang, Yusuke Suita, Michael Murphy, David E Fisher, Conor L Evans
Chemical sun filters are commonly used as active ingredients in sunscreens due to their efficient absorption of ultraviolet (UV) radiation. Yet, it is known that these compounds can photochemically react with UV light and generate reactive oxygen species and oxidative stress in vitro, though this has yet to be validated in vivo. One label-free approach to probe oxidative stress is to measure and compare the relative endogenous fluorescence generated by cellular coenzymes nicotinamide adenine dinucleotides and flavin adenine dinucleotides...
December 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29211022/tracking-functional-tumor-cell-subpopulations-of-malignant-glioma-by-phasor-fluorescence-lifetime-imaging-microscopy-of-nadh
#2
Andrew L Trinh, Hongtao Chen, Yumay Chen, Yuanjie Hu, Zhenzhi Li, Eric R Siegel, Mark E Linskey, Ping H Wang, Michelle A Digman, Yi-Hong Zhou
Intra-tumoral heterogeneity is associated with therapeutic resistance of cancer and there exists a need to non-invasively identify functional tumor subpopulations responsible for tumor recurrence. Reduced nicotinamide adenine dinucleotide (NADH) is a metabolic coenzyme essential in cellular respiration. Fluorescence lifetime imaging microscopy (FLIM) of NADH has been demonstrated to be a powerful label-free indicator for inferring metabolic states of living cells. Using FLIM, we identified a significant shift towards longer NADH fluorescence lifetimes, suggesting an increase in the fraction of protein-bound NADH, in the invasive stem-like tumor-initiating cell (STIC) subpopulation relative to the tumor mass-forming cell (TMC) subpopulation of malignant gliomas...
December 6, 2017: Cancers
https://www.readbyqxmd.com/read/29209088/inhibitory-effects-of-curcumin-and-cyclocurcumin-in-1-methyl-4-phenylpyridinium-mpp-induced-neurotoxicity-in-differentiated-pc12-cells
#3
Sandeep Chakraborty, Artashes Karmenyan, Jin-Wu Tsai, Arthur Chiou
Development and progression of neurodegenerative diseases like Parkinson's disease (PD) involve multiple pathways. Thus, effective therapeutic treatments should intervene to address all these pathways simultaneously for greater success. Most of the current pharmacotherapeutic approaches just supplement striatal dopamine. Hence, natural extracts of plants with therapeutic potential have been explored. Curcuminoids belong to one such group of polyphenol which show immense therapeutic effects. Here, we have used intracellular reactive oxygen species (ROS) measurement, and two-photon fluorescence lifetime imaging microscopy (2P-FLIM) of cellular autofluorescent co-enzyme reduced nicotinamide adenine dinucleotide (NADH) to study the inhibitory effects of curcumin and cyclocurcumin in alleviating PD like neurotoxicity of 1-methyl-4-phenylpyridinium (MPP+) in neuronal growth factor (NGF) induced differentiated PC12 cells...
December 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29203557/a-single-oxidosqualene-cyclase-produces-the-seco-triterpenoid-%C3%AE-onocerin
#4
Aldo Almeida, Lemeng Dong, Bekzod Khakimov, Jean-Etienne André Bassard, Tessa Moses, Frederic Lota, Alain Goossens, Giovanni Appendino, Soren Bak
8,14-seco-triterpenoids are characterized by their unusual open C-ring. Their distribution in nature is rare and scattered in taxonomically unrelated plants. The 8,14-seco-triterpenoid α-onocerin is only known from the evolutionarily distant clubmoss genus Lycopodium and leguminous genus Ononis, which makes the biosynthesis of this seco-triterpenoid intriguing from an evolutionary standpoint. In our experiments with Ononis spinosa, α-onocerin was detected only in the roots. Through transcriptome analysis of the roots, an oxidosqualene cyclase, OsONS1, was identified that produces α-onocerin from squalene-2,3;22,23-dioxide, when transiently expressed in Nicotiana bethaminana...
December 4, 2017: Plant Physiology
https://www.readbyqxmd.com/read/29203404/the-imaging-fcs-diffusion-law-in-the-presence-of-multiple-diffusive-modes
#5
Sapthaswaran Veerapathiran, Thorsten Wohland
The cellular plasma membrane is the barrier over which cells exchange materials and communicate with their surroundings, and thus plays the central role in cellular sensing and metabolism. Therefore, the investigation of plasma membrane organization and dynamics is required for understanding of cellular functions. The plasma membrane is a heterogeneous matrix. The presence of structures such as lipid and protein domains and the cytoskeleton meshwork poses a hindrance to the free diffusion of membrane associated biomolecules...
December 1, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/29196739/imaging-viscosity-of-intragranular-mucin-matrix-in-cystic-fibrosis-cells
#6
Sebastian Requena, Olga Ponomarchuk, Marlius Castillo, Jonathan Rebik, Emmanuelle Brochiero, Julian Borejdo, Ignacy Gryczynski, Sergei V Dzyuba, Zygmunt Gryczynski, Ryszard Grygorczyk, Rafal Fudala
Abnormalities of mucus viscosity play a critical role in the pathogenesis of several respiratory diseases, including cystic fibrosis. Currently, there are no approaches to assess the rheological properties of mucin granule matrices in live cells. This is the first example of the use of a molecular rotor, a BODIPY dye, to quantitatively visualize the viscosity of intragranular mucin matrices in a large population of individual granules in differentiated primary bronchial epithelial cells using fluorescence lifetime imaging microscopy...
December 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29193178/integrated-microfluidic-biosensing-platform-for-simultaneous-confocal-microscopy-and-electrophysiological-measurements-on-bilayer-lipid-membranes-and-ion-channels
#7
Verena C Schulze Greiving, Hans L de Boer, Johan G Bomer, Albert van den Berg, Séverine Le Gac
Combining high-resolution imaging and electrophysiological recordings is key for various types of experimentation on lipid bilayers and ion channels. Here, we propose an integrated biosensing platform consisting of a microfluidic cartridge and a dedicated chip-holder to conduct such dual measurements on suspended lipid bilayers, in a user-friendly manner. To illustrate the potential of the integrated platform, we characterize lipid bilayers in terms of thickness and fluidity while simultaneously monitoring single ion channel currents...
November 29, 2017: Electrophoresis
https://www.readbyqxmd.com/read/29188660/multiphoton-fluorescence-lifetime-imaging-of-chemotherapy-distribution-in-solid-tumors
#8
Marjorie Carlson, Adrienne L Watson, Leah Anderson, David A Largaespada, Paolo P Provenzano
Doxorubicin is a commonly used chemotherapeutic employed to treat multiple human cancers, including numerous sarcomas and carcinomas. Furthermore, doxorubicin possesses strong fluorescent properties that make it an ideal reagent for modeling drug delivery by examining its distribution in cells and tissues. However, while doxorubicin fluorescence and lifetime have been imaged in live tissue, its behavior in archival samples that frequently result from drug and treatment studies in human and animal patients, and murine models of human cancer, has to date been largely unexplored...
November 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29181426/mitochondrial-matrix-ph-as-a-decisive-factor-in-neurometabolic-imaging
#9
Patrick M Schaefer, Diana Hilpert, Moritz Niederschweiberer, Larissa Neuhauser, Sviatlana Kalinina, Enrico Calzia, Angelika Rueck, Bjoern von Einem, Christine A F von Arnim
Alterations of cellular bioenergetics are a common feature in most neurodegenerative disorders. However, there is a selective vulnerability of different brain regions, cell types, and even mitochondrial populations to these metabolic disturbances. Thus, the aim of our study was to establish and validate an in vivo metabolic imaging technique to screen for mitochondrial function on the subcellular level. Based on nicotinamide adenine dinucleotide (phosphate) fluorescence lifetime imaging microscopy [NAD(P)H FLIM], we performed a quantitative correlation to high-resolution respirometry...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/29161014/toward-an-axial-nanoscale-ruler-for-fluorescence-microscopy
#10
Sabrina Simoncelli, Maria Makarova, William Wardley, Dylan M Owen
In the discussion of resolution in optical microscopy, axial precision has often come second to its lateral counterpart. However, biological systems make no special arrangements for our preferred direction of imaging. The ability to measure axial distances, that is, the heights of fluorophores relative to a plane of reference, is thus of paramount importance and has been the subject of several recent advances. A novel method is to modify the fluorescence emission based on the height of the individual fluorophore, such that its z-position is encoded somehow in the detected signal...
November 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/29160862/time-resolved-photoluminescence-microscopy-for-the-analysis-of-semiconductor-based-paint-layers
#11
Daniela Comelli, Alessia Artesani, Austin Nevin, Sara Mosca, Victor Gonzalez, Myriam Eveno, Gianluca Valentini
In conservation, science semiconductors occur as the constituent matter of the so-called semiconductor pigments, produced following the Industrial Revolution and extensively used by modern painters. With recent research highlighting the occurrence of various degradation phenomena in semiconductor paints, it is clear that their detection by conventional optical fluorescence imaging and microscopy is limited by the complexity of historical painting materials. Here, we illustrate and prove the capabilities of time-resolved photoluminescence (TRPL) microscopy, equipped with both spectral and lifetime sensitivity at timescales ranging from nanoseconds to hundreds of microseconds, for the analysis of cross-sections of paint layers made of luminescent semiconductor pigments...
November 21, 2017: Materials
https://www.readbyqxmd.com/read/29155761/advanced-confocal-microscopy-techniques-to-study-protein-protein-interactions-and-kinetics-at-dna-lesions
#12
Soňa Legartová, Jana Suchánková, Jana Krejčí, Alena Kovaříková, Eva Bártová
Local microirradiation with lasers represents a useful tool for studies of DNA-repair-related processes in live cells. Here, we describe a methodological approach to analyzing protein kinetics at DNA lesions over time or protein-protein interactions on locally microirradiated chromatin. We also show how to recognize individual phases of the cell cycle using the Fucci cellular system to study cell-cycle-dependent protein kinetics at DNA lesions. A methodological description of the use of two UV lasers (355 nm and 405 nm) to induce different types of DNA damage is also presented...
November 12, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29155738/imaging-amyloid-tissues-stained-with-luminescent-conjugated-oligothiophenes-by-hyperspectral-confocal-microscopy-and-fluorescence-lifetime-imaging
#13
Sofie Nyström, Marcus Bäck, K Peter R Nilsson, Per Hammarström
Proteins that deposit as amyloid in tissues throughout the body can be the cause or consequence of a large number of diseases. Among these we find neurodegenerative diseases such as Alzheimer's and Parkinson's disease afflicting primarily the central nervous system, and systemic amyloidosis where serum amyloid A, transthyretin and IgG light chains deposit as amyloid in liver, carpal tunnel, spleen, kidney, heart, and other peripheral tissues. Amyloid has been known and studied for more than a century, often using amyloid specific dyes such as Congo red and Thioflavin T (ThT) or Thioflavin (ThS)...
October 20, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29148433/a-flow-bioreactor-system-compatible-with-real-time-two-photon-fluorescence-lifetime-imaging-microscopy
#14
Nian Shen, Julia A Riedl, Daniel A Carvajal-Berrio, Zackary Davis, Michael G Monaghan, Shannon Lee Layland, Svenja Hinderer, Katja Schenke-Layland
Bioreactors are essential cell and tissue culture tools that allow the introduction of biophysical signals into in vitro cultures. One major limitation is the need to interrupt experiments and sacrifice samples at certain time points for analyses. To address this issue, we designed a bioreactor that combines high-resolution contact-free imaging and continuous flow in a closed system that is compatible with various types of microscopes. The high-throughput fluid flow bioreactor was combined with two-photon fluorescence lifetime imaging microscopy (2P-FLIM) and validated...
November 17, 2017: Biomedical Materials
https://www.readbyqxmd.com/read/29142589/flim-fret-analyzer-open-source-software-for-automation-of-lifetime-based-fret-analysis
#15
Jiho Kim, Yury Tsoy, Jan Persson, Regis Grailhe
Background: Despite the broad use of FRET techniques, available methods for analyzing protein-protein interaction are subject to high labor and lack of systematic analysis. We propose an open source software allowing the quantitative analysis of fluorescence lifetime imaging (FLIM) while integrating the steady-state fluorescence intensity information for protein-protein interaction studies. Findings: Our developed open source software is dedicated to fluorescence lifetime imaging microscopy (FLIM) data obtained from Becker & Hickl SPC-830...
2017: Source Code for Biology and Medicine
https://www.readbyqxmd.com/read/29120943/native-prion-protein-homodimers-are-destabilized-by-oligomeric-amyloid-%C3%AE-1-42-species-as-shown-by-single-molecule-imaging
#16
Sachin S Tiwari, Yuki M Shirai, Yuri L Nemoto, Kumiko Kojima, Kenichi G N Suzuki
Prion proteins (PrPc) are receptors for amyloid β 1-42 (Aβ1-42) oligomers, but we do not know the impact of Aβ1-42 binding to PrPc on the interaction of membrane-bound PrPc with molecules that regulate downstream biological pathways. Stability of the PrPc dimeric complex and subsequent intermolecular interactions with membranous or cytoplasmic molecules are important for physiological functions of PrPc including neuroprotection. The principal aim of this study was to determine whether homodimer lifetime of PrPc is affected by the presence of Aβ1-42 oligomers...
November 8, 2017: Neuroreport
https://www.readbyqxmd.com/read/29115129/time-gated-luminescence-imaging-of-immunolabeled-human-tissues
#17
Ting Chen, Rui Hong, Darren Magda, Christopher Bieniarz, Larry Morrison, Lawrence W Miller
Multiplexed immunofluorescence imaging of formalin-fixed, paraffin-embedded tissues is a powerful tool for investigating proteomic profiles and diagnosing disease. However, conventional immunofluorescence with organic dyes is limited in the number of colors that can be simultaneously visualized, is made less sensitive by tissue autofluorescence background, and is usually incompatible with commonly used hematoxylin and eosin staining. Herein, we demonstrate the comparative advantages of using time-gated luminescence microscopy in combination with an emissive Tb(III) complex, Lumi4-Tb, for tissue imaging in terms of sensitivity, multiplexing potential, and compatibility with common immunohistochemistry protocols...
November 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29106971/interaction-of-a-quercetin-derivative-lensoside-a%C3%AE-with-liposomal-membranes
#18
Bozena Pawlikowska-Pawlega, Justyna Kapral, Antoni Gawron, Anna Stochmal, Jerzy Zuchowski, Lukasz Pecio, Rafal Luchowski, Wojciech Grudzinski, Wieslaw I Gruszecki
Lensoside Aβ, representing the flavonol glycosides, is a compound isolated from the aerial parts of edible lentil (Lens culinaris) cultivar Tina. This substance arouse interest because so far there is very little data about secondary metabolites isolated from the leaves and stems of this plant. Additionally, bioactive potential of flavonoids is directly coupled with the membranes as a primary target of their physiological and pharmacological activity. The aim of this study was to investigate the effect of lensoside Aβ on lipid membranes...
October 26, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29106397/ultrasensitive-optical-imaging-with-lanthanide-lumiphores
#19
Ukrae Cho, Daniel P Riordan, Paulina Ciepla, Kiranmai S Kocherlakota, James K Chen, Pehr B Harbury
In principle, the millisecond emission lifetimes of lanthanide chelates should enable their ultrasensitive detection in biological systems by time-resolved optical microscopy. In practice, however, lanthanide imaging techniques have provided no better sensitivity than conventional fluorescence microscopy. Here, we identified three fundamental problems that have impeded lanthanide microscopy: low photon flux, inefficient excitation, and optics-derived background luminescence. We overcame these limitations with a new lanthanide imaging modality, transreflected illumination with luminescence resonance energy transfer (trLRET), which increases the time-integrated signal intensities of lanthanide lumiphores by 170-fold and the signal-to-background ratios by 75-fold...
November 6, 2017: Nature Chemical Biology
https://www.readbyqxmd.com/read/29092164/uv-superconducting-nanowire-single-photon-detectors-with-high-efficiency-low-noise-and-4-k-operating-temperature
#20
E E Wollman, V B Verma, A D Beyer, R M Briggs, B Korzh, J P Allmaras, F Marsili, A E Lita, R P Mirin, S W Nam, M D Shaw
For photon-counting applications at ultraviolet wavelengths, there are currently no detectors that combine high efficiency (> 50%), sub-nanosecond timing resolution, and sub-Hz dark count rates. Superconducting nanowire single-photon detectors (SNSPDs) have seen success over the past decade for photon-counting applications in the near-infrared, but little work has been done to optimize SNSPDs for wavelengths below 400 nm. Here, we describe the design, fabrication, and characterization of UV SNSPDs operating at wavelengths between 250 and 370 nm...
October 30, 2017: Optics Express
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