Leica Science Lab - Tag : Fluorophore https://www.leica-microsystems.com//science-lab/tag/fluorophore/ Article tagged with Fluorophore en-US https://www.leica-microsystems.com/30694 Confocal Microscopy Fluorescence Microscopy Infection of the novel coronavirus SARS-CoV-2 can be blocked by a human monoclonal antibody Vaccines and targeted therapeutics for treatment of the respiratory disease COVID-19, caused by the coronavirus SARS-CoV-2, are currently lacking. Based on the results of this study, it was reported for the first time that a human monoclonal antibody, 47D11, can neutralize SARS-CoV-2 in cell culture. This cross-neutralizing antibody targets a communal epitope on the virus via a mechanism that is independent of receptor-binding inhibition. It will be useful for development of antigen detection tests and serological assays targeting SARS-CoV-2. https://www.leica-microsystems.com/science-lab/infection-of-the-novel-coronavirus-sars-cov-2-can-be-blocked-by-a-human-monoclonal-antibody/ Mon, 24 Aug 2020 12:29:00 +0000 https://www.leica-microsystems.com/26264 Super-Resolution The Guide to STED Sample Preparation This guide is intended to help users optimize sample preparation for stimulated emission depletion (STED) nanoscopy, specifically when using the TCS SP8 STED 3X nanoscope from Leica Microsystems. It gives an overview of fluorescent labels used for single color STED imaging and a ranking of their performance. Fluorescent label combinations for dual and triple color STED imaging that minimize cross-talk during detection are recommended. There is a discussion of considerations for immunofluorescence labeling and a detailed protocol to obtain high quality images, with a high signal/noise (S/N) ratio, of interesting structures in a specimen. Important details for sample mounting and substrates that enable optimal imaging, minimizing aberrations and autofluorescence due to the mounting medium, are reviewed. Finally, for STED imaging of live-cells, the most appropriate fluorescent labels are mentioned, both fluorescent proteins (FPs) and organic fluorophores which give the best performance. https://www.leica-microsystems.com/science-lab/the-guide-to-sted-sample-preparation/ Mon, 22 Jul 2019 17:00:00 +0000 https://www.leica-microsystems.com/19872 Super-Resolution Abstracts of the 7th European Super-Resolution User-Club Meeting The 7th Super-Resolution User Club Meeting was held in collaboration with Prof Pavel Hozák , at the Institute of Molecular Genetics of the ASCR in Prague. Keeping the event close to science is one of the founding principles of the event, allowing all participants to network, share and explore exciting new super-resolution and nanoscopy applications. Central to this are the scientific talks given during the meeting, with this cutting-edge microscopy technique as their central theme. A wide selection of topics were covered, prompting interesting discussions during the workshops. https://www.leica-microsystems.com/science-lab/abstracts-of-the-7th-european-super-resolution-user-club-meeting/ Sun, 17 Dec 2017 23:00:00 +0000 Prof. DrSc. Pavel Hozák, Prof. Dr. Torsten Ochsenreiter, Dr. Martin Offterdinger, Dr. Jordi Andilla, Ph.D. Marc van Zandvoort, Prof. Christian Eggeling, Dr. Susan Cox, Dr. Eugene Katrukha, Dr. Jindřiška Fišerová, Dr. Camille Boutin https://www.leica-microsystems.com/19773 Fluorescence Microscopy Basics in Microscopy The Fundamentals and History of Fluorescence and Quantum Dots At some point in your research and science career, you will no doubt come across fluorescence microscopy. This ubiquitous technique has transformed the way in which microscopists can image, tag and trace anything from whole organisms to single proteins and beyond. In this article, we will examine what is meant by "fluorescence", the history and basic physics behind its definition, the discovery and application of Green Fluorescent Protein (GFP) and a look at the rapidly expanding field of fluorescent probes including Quantum Dots. https://www.leica-microsystems.com/science-lab/the-fundamentals-and-history-of-fluorescence-and-quantum-dots/ Wed, 15 Nov 2017 16:44:00 +0000 PhD Martin Wilson https://www.leica-microsystems.com/19260 Basics in Microscopy Fluorescence Microscopy Milestones in Incident Light Fluorescence Microscopy Since the middle of the last century, fluorescence microscopy developed into a bio scientific tool with one of the biggest impacts on our understanding of life. Watching cells and proteins with the help of fluorescence molecules is a standard method in nearly every life science discipline today. This broad application range goes back to the technical work of some researchers who wanted to improve and simplify fluorescence microscopic labor. One person who was involved in that development was the Dutch medic Johann Sebastiaan Ploem. https://www.leica-microsystems.com/science-lab/milestones-in-incident-light-fluorescence-microscopy/ Mon, 06 Mar 2017 08:39:00 +0000 Dr. Christoph Greb https://www.leica-microsystems.com/19107 Confocal Microscopy Fluorescence Microscopy Testing the Münch Hypothesis of Long Distance Phloem Transport in Plants Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for the Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues. https://www.leica-microsystems.com/science-lab/testing-the-muench-hypothesis-of-long-distance-phloem-transport-in-plants/ Tue, 14 Feb 2017 09:08:00 +0000 https://www.leica-microsystems.com/18994 Fluorescence Microscopy Live-Cell Imaging Widefield Microscopy Chronic Inflammation Under the Microscope In the course of chronic inflammation certain body areas are recurrently inflamed. This goes along with many human diseases. With the help of widefield light microscopy, the underlying processes can be examined from a cellular level to whole organisms. This article presents several widefield microscopy applications such as immunofluorescence, live-cell imaging, histology, and ratiometric analysis to get insight into the development of chronic inflammation, the related diseases, and their treatment. https://www.leica-microsystems.com/science-lab/chronic-inflammation-under-the-microscope/ Mon, 09 Jan 2017 17:42:00 +0000 M.Sc. Jan Neumann, M.Sc. Anne Scherhag, Susanne Otten, Ph.D. Fangxia Shen, Anna Lena Leifke, Dr. Udo Birk, Dr. Christoph Greb, Dr. Kurt Lucas, Prof. Dr. Dr. Christoph Cremer https://www.leica-microsystems.com/18935 Confocal Microscopy Fluorescence Microscopy Multispectral Phloem-Mobile Probes: Properties and Applications Using Arabidopsis (Arabidopsis thaliana) seedlings, we identified a range of small fluorescent probes that entered the translocation stream and were unloaded at the root tip. These probes had absorbance/emission maxima ranging from 367/454 to 546/576 nm and represent a versatile toolbox for studying phloem transport. Of the probes that we tested, naturally occurring fluorescent coumarin glucosides (esculin and fraxin) were phloem loaded and transported in oocytes by the sucrose transporter, AtSUC2. Arabidopsis plants in which AtSUC2 was replaced with barley (Hordeum vulgare) sucrose transporter (HvSUT1), which does not transport esculin in oocytes, failed to load esculin into the phloem. https://www.leica-microsystems.com/science-lab/multispectral-phloem-mobile-probes-properties-and-applications/ Tue, 29 Nov 2016 16:44:00 +0000 https://www.leica-microsystems.com/18876 Super-Resolution Abstracts of the 6th European Super-Resolution User-Club Meeting The 6th European Super-Resolution User Club Meeting was held in collaboration with Dr. Timo Zimmermann, CRG, and Dr. Pablo Loza-Alvarez, ICFO, Barcelona. According to the founding principle of the club of keeping close to science, both imaging facilities at the CRG and the ICFO opened their doors to the User Club members, allowing them to explore exciting super-resolution and and nanoscopy applications. The meeting agenda covered highly relevant talks around this year’s central theme “Core Facilities and Super-Resolution Microscopy”, as well as plenty of opportunities to network amongst super-resolution users from different European countries. Here we present the abstracts of the talks held during the meeting. https://www.leica-microsystems.com/science-lab/abstracts-of-the-6th-european-super-resolution-user-club-meeting/ Tue, 18 Oct 2016 08:59:00 +0000 Dr. Timo Zimmermann, Dr. Pablo Loza-Alvarez, Dr. Alberto Lleó, Dr. Gražvydas Lukinavicius, Prof. Philip Tinnefeld, Prof. Hans-Georg Kräusslich, Dr. Steffen Dietzel, Dr. Valeria Caiolfa, Lorenzo Albertazzi https://www.leica-microsystems.com/18801 Super-Resolution Fluorescence Microscopy Measuring the 3D STED-PSF with a new Type of Fluorescent Beads A new type of fluorescent bead is presented by GATTAquant. These beads, called GATTA-Beads, are characterized by a small diameter (23 nm), high intensity and size uniformity. In combination with state-of the-art STED microscopes such as the Leica TCS SP8 STED 3X and high-end image restoration methods available in the Huygens Software, it is shown that these new beads can be used for accurate STED PSF characterization in 3D. Furthermore, it is shown that the measured 3D STED-PSF can be used to improve image restoration quality in combination with STED deconvolution methods available in the Huygens Software. https://www.leica-microsystems.com/science-lab/measuring-the-3d-sted-psf-with-a-new-type-of-fluorescent-beads/ Wed, 21 Sep 2016 06:54:00 +0000 PhD Jürgen J. Schmied, MSc Remko Dijkstra, Ph.D. Max B. Scheible, Ph.D. Giulia M. R. De Luca, PhD Jochen J. Sieber https://www.leica-microsystems.com/13942 Fluorescence Microscopy Quantitative Imaging Video Talk by Roger Tsien: Fluorescent Protein Indicators In this talk, Roger Tsien discusses how fluorescent proteins have been turned into indicators for a wide variety of biological molecules, including pH, ions, redox potential, and signaling molecules like phosphoinositides. The talk also covers reporters used to measure the activity of enzymes like kinases, phosphatases, and proteases. It covers both single proteins whose intensity or wavelength change, as well as reporters using Förster resonance energy transfer (FRET). https://www.leica-microsystems.com/science-lab/video-talk-by-roger-tsien-fluorescent-protein-indicators/ Tue, 16 Aug 2016 10:29:00 +0000 PhD Roger Y. Tsien https://www.leica-microsystems.com/15428 Confocal Microscopy Live-Cell Imaging Highly Selective Fluorescent and Colorimetric Probe for Live-cell Monitoring of Sulphide Based on Bioorthogonal Reaction H2S is the third endogenously generated gaseous signaling compound and has also been known to involve a variety of physiological processes. To better understand its physiological and pathological functions, efficient methods for monitoring of H2S are desired. Azide fluorogenic probes are popular because they can take place bioorthogonal reactions. In this work, by employing a fluorescein derivative as the fluorophore and an azide group as the recognition unit, we reported a new probe 5-azidofluorescein for H2S with improved sensitivity and selectivety. https://www.leica-microsystems.com/science-lab/highly-selective-fluorescent-and-colorimetric-probe-for-live-cell-monitoring-of-sulphide-based-on-bioorthogonal-reaction/ Fri, 29 Jul 2016 11:41:00 +0000 https://www.leica-microsystems.com/13935 Fluorescence Microscopy Video Talk by Roger Tsien: Fluorescent Proteins Live cell imaging has been revolutionized by the discovery of the green fluorescent protein (GFP). This lecture covers the history of GFP, how it folds and becomes fluorescent, how it has been mutated to produce additional colors (blue, cyan, yellow), and the discovery of red fluorescent proteins from corals. It also covers novel photoswitchable and photoactivatible fluorescent proteins, whose color can be changed by light, and new infrared fluorescent proteins. https://www.leica-microsystems.com/science-lab/video-talk-by-roger-tsien-fluorescent-proteins/ Wed, 07 Oct 2015 16:55:00 +0000 PhD Roger Y. Tsien https://www.leica-microsystems.com/16035 Fluorescence Microscopy Live-Cell Imaging Basics in Microscopy Fluorescent Proteins Illuminate Cell Biology Green fluorescent protein (GFP) isolated from the jellyfish Aequorea victoria and GFP-like fluorescent proteins from other animals have had an important role in the technical innovations that have driven these advances. This poster provides a comprehensive user's guide to fluorescent proteins and sensors , their key properties and the cell biological questions to which they can be applied. https://www.leica-microsystems.com/science-lab/fluorescent-proteins-illuminate-cell-biology/ Fri, 18 Sep 2015 09:03:00 +0000 https://www.leica-microsystems.com/16033 Super-Resolution STED Nanoscopy with Fluorescent Quantum Dots The widely popular class of quantum-dot molecular labels could so far not be utilized as standard fluorescent probes in STED (stimulated emission depletion) nanoscopy. This is because broad quantum-dot excitation spectra extend deeply into the spectral bands used for STED, thus compromising the transient fluorescence silencing required for attaining super-resolution. https://www.leica-microsystems.com/science-lab/sted-nanoscopy-with-fluorescent-quantum-dots/ Thu, 13 Aug 2015 09:24:00 +0000 https://www.leica-microsystems.com/15295 Fluorescence Microscopy How to Prepare Your Specimen for Immunofluorescence Microscopy Immunofluorescence (IF) is a powerful method for visualizing intracellular processes, conditions and structures. IF preparations can be analyzed by various microscopy techniques (e.g. CLSM, Epifluorescence, TIRF, GSDIM), depending on the application or the researcher’s interest. Meanwhile, IF has become indispensable for a large number of research groups which have at least access to a simple fluorescence microscope. https://www.leica-microsystems.com/science-lab/how-to-prepare-your-specimen-for-immunofluorescence-microscopy/ Mon, 13 Apr 2015 14:22:00 +0000 Florian Hoff https://www.leica-microsystems.com/14080 Fluorescence Microscopy Live-Cell Imaging Spectral and Structural Comparison Between Bright and Dim Green Fluorescent Proteins in Amphioxus The cephalochordate Amphioxus naturally co-expresses fluorescent proteins (FPs) with different brightness, which thus offers the rare opportunity to identify FP molecular feature/s that are associated with greater/lower intensity of fluorescence. Here, we describe the spectral and structural characteristics of green FP (bfloGFPa1) with perfect (100%) quantum efficiency yielding to unprecedentedly-high brightness, and compare them to those of co-expressed bfloGFPc1 showing extremely-dim brightness due to low (0.1%) quantum efficiency. https://www.leica-microsystems.com/science-lab/spectral-and-structural-comparison-between-bright-and-dim-green-fluorescent-proteins-in-amphioxus/ Thu, 28 Aug 2014 15:54:00 +0000 https://www.leica-microsystems.com/12284 Super-Resolution The Force of the Dark Side – Embedding Media for GSDIM Super-Resolution Localization Microscopy Super-resolution microscopy such as Stimulated Emission Depletion (STED) and single-molecule based techniques rely on the same principle for breaking the diffraction limit: the unwanted fluorescence signals are switched off during the image acquisition process. Consequently, Ground State Depletion followed by Individual Molecule Return (GSDIM) microscopy and related techniques like PALM, STORM and dSTORM use metastable dark states of a fluorophore for temporal separation of single molecules. https://www.leica-microsystems.com/science-lab/the-force-of-the-dark-side-embedding-media-for-gsdim-super-resolution-localization-microscopy/ Thu, 23 Jan 2014 18:49:00 +0000 Sebastian Bänfer https://www.leica-microsystems.com/9350 Confocal Microscopy Fluorescence Microscopy Live-Cell Imaging Handbook of Optical Filters for Fluorescence Microscopy Fluorescence microscopy and other light-based applications require optical filters that have demanding spectral and physical characteristics. Often, these characteristics are application-specific and an optic that might be appropriate and optimal for one is both inappropriate and sub-optimal for another. https://www.leica-microsystems.com/science-lab/handbook-of-optical-filters-for-fluorescence-microscopy/ Tue, 06 Aug 2013 07:59:00 +0000 BSc. Jay Reichman https://www.leica-microsystems.com/9759 Quantitative Imaging Step by Step Guide for FRAP Experiments Fluorescence Recovery After Photobleaching (FRAP) has been considered the most widely applied method for observing translational diffusion processes of macromolecules. The resulting information can be used to determine kinetic properties, like the diffusion coefficient, mobile fraction, and transport rate of the fluorescently labeled molecules. FRAP employs irradiation of a fluorophore with a short laser pulse. State of the art laser scanning microscopes, like the TCS SP8 confocal system, have the advantage of using a high intensity laser for photobleaching and a low intensity laser for image recording. With the LAS AF application wizard you can choose between different ways to carry out a FRAP experiment. https://www.leica-microsystems.com/science-lab/step-by-step-guide-for-frap-experiments/ Fri, 17 May 2013 13:50:00 +0000 Dr. Jan Schröder https://www.leica-microsystems.com/6497 Widefield Microscopy Super-Resolution Widefield Super-Resolution with GSDIM Great advancements in biology have been possible by using fluorescence microscopy. So far, the resolution of the images was limited due to physical constraints. In the past couple of years, new methods evolved circumventing these limitations and bringing fluorescence microscopy to a new level of resolution, boosting the possibilities in science with fluorescence microscopes. https://www.leica-microsystems.com/science-lab/widefield-super-resolution-with-gsdim/ Wed, 11 Jul 2012 22:00:00 +0000 Dr. Marko Lampe https://www.leica-microsystems.com/6345 Fluorescence Microscopy Widefield Microscopy Fluorescent Dyes A basic principle in fluorescence microscopy is the highly specific visualization of cellular components with the help of a fluorescing agent. This can be a fluorescing protein – for example GFP – genetically linked to the protein of interest. If cloning is impossible – for instance in histologic samples – it is required to use other techniques like immunofluorescence staining to visualize the protein of interest. https://www.leica-microsystems.com/science-lab/fluorescent-dyes/ Sun, 10 Jun 2012 22:00:00 +0000 Dr. Christoph Greb https://www.leica-microsystems.com/5890 Fluorescence Microscopy Basics in Microscopy Basic Principles of Luminescence There are a lot of light-emitting processes occurring in nature. Luminescence is an umbrella term for those kinds of events where light emission is not the result of high temperatures. This article depicts the different forms of luminescences and goes into detail in the case of fluorescence. Relevant technical terms describing a fluorochrome, like quenching, bleaching or quantum yield, are explained in the second part of the article to give detailed insights into basic characteristics of fluorescent molecules. https://www.leica-microsystems.com/science-lab/basic-principles-of-luminescence/ Mon, 09 Apr 2012 22:00:00 +0000 Dr. Christoph Greb https://www.leica-microsystems.com/4758 Live-Cell Imaging Neuroscience Ratiometric Imaging Many fundamental functions of a cell strongly depend on delicate, but nevertheless dynamic balances of ions (e.g. calcium, magnesium), voltage potentials and pH between the cell’s cytosol and the surrounding extracellular space. Ratiometric imaging allows reliable estimations of ion concentrations and pH or voltage changes by measuring fluorophore emission shifts. https://www.leica-microsystems.com/science-lab/ratiometric-imaging/ Sun, 11 Dec 2011 23:00:00 +0000 Dr. Thomas Veitinger https://www.leica-microsystems.com/4713 Fluorescence Microscopy Modern Fluorescent Proteins and their Biological Applications Here we present two review articles on fluorescent proteins and their biological applications. These first article reviews our current knowledge of blue, green, and red chromophore formation in permanently emitting FPs, photoactivatable FPs, and fluorescent timers. The second article focuses on novel monomeric RFPs and their application for studying gene expression, nuclear localization, and dynamics using advanced imaging. https://www.leica-microsystems.com/science-lab/modern-fluorescent-proteins-and-their-biological-applications/ Fri, 18 Nov 2011 12:50:00 +0000 https://www.leica-microsystems.com/6918 Super-Resolution Applications, Labeling Strategies and Fluorophores for Super-Resolution The free online webinar on super-resolution presented by Leica Microsystems in association with Microscopy & Analysis took place on Tuesday, 15 November 2011. Register and view the webinar on demand. https://www.leica-microsystems.com/science-lab/applications-labeling-strategies-and-fluorophores-for-super-resolution/ Tue, 15 Nov 2011 15:52:00 +0000 Dr. Marko Lampe https://www.leica-microsystems.com/4182 Fluorescence Microscopy Basics in Microscopy An Introduction to Fluorescence Fluorescence is widely used in microscopy and an important tool for observing the distribution of specific molecules. Most molecules in cells do not fluoresce. They therefore have to be marked with fluorescing molecules called fluorochromes. https://www.leica-microsystems.com/science-lab/an-introduction-to-fluorescence/ Tue, 31 May 2011 13:29:00 +0000 Wymke Ockenga https://www.leica-microsystems.com/9682 Fluorescence Microscopy Multi-Wavelength Epi-Illumination in Fluorescence Microscopy Fluorescence is a process where a substance after having absorbed light (photons) emitts a radiation the wavelength (colour) of which is longer than that of the absorbed light, and where this emission stops immediately after cessation of the excitation. This phenomenon is the basic element of fluorescence microscopy and its application. https://www.leica-microsystems.com/science-lab/multi-wavelength-epi-illumination-in-fluorescence-microscopy/ Sat, 01 Dec 2001 15:35:00 +0000 Professor em. Johan Sebastiaan Ploem, Dr. Friedrich Walter