scholarly journals Direct fluorescent-dye labeling of α-tubulin in mammalian cells for live cell and superresolution imaging

2017 ◽  
Vol 28 (21) ◽  
pp. 2747-2756 ◽  
Author(s):  
Tomer Schvartz ◽  
Noa Aloush ◽  
Inna Goliand ◽  
Inbar Segal ◽  
Dikla Nachmias ◽  
...  
Keyword(s):  
High Resolution ◽  
Genetic Code ◽  
Mammalian Cells ◽  
Fluorescent Dyes ◽  
Video Recording ◽  
Live Cell ◽  
Live Cells ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Genetic Code Expansion

Genetic code expansion and bioorthogonal labeling provide for the first time a way for direct, site-specific labeling of proteins with fluorescent-dyes in live cells. Although the small size and superb photophysical parameters of fluorescent-dyes offer unique advantages for high-resolution microscopy, this approach has yet to be embraced as a tool in live cell imaging. Here we evaluated the feasibility of this approach by applying it for α-tubulin labeling. After a series of calibrations, we site-specifically labeled α-tubulin with silicon rhodamine (SiR) in live mammalian cells in an efficient and robust manner. SiR-labeled tubulin successfully incorporated into endogenous microtubules at high density, enabling video recording of microtubule dynamics in interphase and mitotic cells. Applying this labeling approach to structured illumination microscopy resulted in an increase in resolution, highlighting the advantages in using a smaller, brighter tag. Therefore, using our optimized assay, genetic code expansion provides an attractive tool for labeling proteins with a minimal, bright tag in quantitative high-resolution imaging.

scholarly journals A straightforward approach for bioorthogonal labeling of proteins and organelles in live mammalian cells, using a short peptide tag

2019 ◽  
Author(s):  
Inbar Segal ◽  
Dikla Nachmias ◽  
Eyal Arbely ◽  
Natalie Elia
Keyword(s):  
Mammalian Cells ◽  
Fluorescent Dyes ◽  
Specific Protein ◽  
Live Cell ◽  
Cell Labeling ◽  
Live Cells ◽  
Bioorthogonal Labeling ◽  
Labeling Approach ◽  
Genetic Code Expansion ◽  
Live Cell Labeling

AbstractIn the high-resolution microscopy era, genetic code expansion (GCE)-based bioorthogonal labeling offers an elegant way for direct labeling of proteins in live cells with fluorescent dyes. This labeling approach is currently not broadly used live cell applications, partly because it needs to be adjusted to the specific protein under study. Here, we present a generic, 14-residues long, N-terminal tag for GCE-based labeling of proteins in live mammalian cells. Using this tag, we generated a library of GCE-based organelle markers, demonstrating the applicability of the tag for labeling a plethora of proteins and organelles. Finally, we show that the HA epitope, used as a backbone in our tag, can be substituted with other epitopes and, in some cases, can be completely removed, reducing the tag length to 5 residues. The GCE-tag presented here offers a powerful, easy-to-implement tool for live cell labeling of cellular proteins with small and bright probes.

scholarly journals Extending resolution of structured illumination microscopy with sparse deconvolution

2021 ◽  
Author(s):  
Weisong Zhao ◽  
Shiqun Zhao ◽  
Liuju Li ◽  
Xiaoshuai Huang ◽  
Shijia Xing ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Super Resolution ◽  
Live Cell ◽  
Frame Rate ◽  
Live Cells ◽  
Photon Flux ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Spatiotemporal Resolution

Abstract The spatial resolutions of live-cell super-resolution microscopes are limited by the maximum collected photon flux. Taking advantage of a priori knowledge of the sparsity and continuity of biological structures, we develop a deconvolution algorithm that further extends the resolution of super-resolution microscopes under the same photon budgets by nearly twofold. As a result, sparse structured illumination microscopy (Sparse-SIM) achieves ~60 nm resolution at a 564 Hz frame rate, allowing it to resolve intricate structural intermediates, including small vesicular fusion pores, ring-shaped nuclear pores formed by different nucleoporins, and relative movements between the inner and outer membranes of mitochondria in live cells. Likewise, sparse deconvolution can be used to increase the three-dimensional resolution and contrast of spinning-disc confocal-based SIM (SD-SIM), and operates under conditions with the insufficient signal-to-noise-ratio, all of which allows routine four-color, three-dimensional, ~90 nm resolution live-cell super-resolution imaging. Overall, sparse deconvolution may be a general tool to push the spatiotemporal resolution limits of live-cell fluorescence microscopy.

scholarly journals Imaging tissues and cells beyond the diffraction limit with structured illumination microscopy and Bayesian image reconstruction

2018 ◽  
Author(s):  
Jakub Pospíšil ◽  
Tomáš Lukeš ◽  
Justin Bendesky ◽  
Karel Fliegel ◽  
Kathrin Spendier ◽  
...  
Keyword(s):  
High Resolution ◽  
Open Source ◽  
Fluorescent Protein ◽  
Super Resolution ◽  
Live Cells ◽  
Structured Illumination ◽  
Optical Sectioning ◽  
Structured Illumination Microscopy ◽  
Raw Data ◽  
Bayesian Image Reconstruction

AbstractBackgroundStructured illumination microscopy (SIM) is a family of methods in optical fluorescence microscopy that can achieve both optical sectioning and super-resolution effects. SIM is a valuable method for high resolution imaging of fixed cells or tissues labeled with conventional fluorophores, as well as for imaging the dynamics of live cells expressing fluorescent protein constructs. In SIM, one acquires a set of images with shifting illumination patterns. This set of images is subsequently treated with image analysis algorithms to produce an image with reduced out-of-focus light (optical sectioning) and/or with improved resolution (super-resolution).FindingsFive complete and freely available SIM datasets are presented including raw and analyzed data. We report methods for image acquisition and analysis using open source software along with examples of the resulting images when processed with different methods. We processed the data using established optical sectioning SIM and super-resolution SIM methods, and with newer Bayesian restoration approaches which we are developing.ConclusionVarious methods for SIM data acquisition and processing are actively being developed, but complete raw data from SIM experiments is not typically published. Publicly available, high quality raw data with examples of processed results will aid researchers when developing new methods in SIM. Biologists will also find interest in the high-resolution images of animal tissues and cells we acquired. All of the data was processed with SIMToolbox, an open source and freely available software solution for SIM.

A Platinum(II) Based Correlative Probe for Bacteria

2019 ◽  
Author(s):  
Anna Maria Ranieri ◽  
Kathryn Leslie ◽  
Song Huang ◽  
Stefano Stagni ◽  
Denis Jacquemin ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Super Resolution ◽  
Molecular Probes ◽  
Live Cells ◽  
Structured Illumination ◽  
Luminescent Probe ◽  
Structured Illumination Microscopy ◽  
Cellular Localisation ◽  
Super Resolution Microscopy ◽  
Nanosims Analysis

There is a lack of molecular probes for imaging bacteria, in comparison to the array of such tools available for the imaging of mammalian cells. This is especially so for correlative probes, which are proving to be powerful tools for enhancing the imaging of live cells. In this work a platinum(II)-naphthalimide molecule has been developed to extend small molecule correlative probes to bacterial imaging. The probe was designed to exploit the naphthalimide moiety as a luminescent probe for super-resolution microscopy, with the platinum(II) centre enabling visualisation of the complex with ion nanoscopy. Photophysical characterisation and theoretical studies confirmed that the emission properties of the naphthalimide are not altered by the platinum(II) centre. Structured illumination microscopy (SIM) imaging on live <i>Bacillus cereus</i>revealed that the platinum(II) centre does not change the sub-cellular localisation of the naphthalimide, and confirmed the suitability of the probe for super-resolution microscopy. NanoSIMS analysis of the sample was used to monitor the uptake of the platinum(II) complex within the bacteria and proved the correlative action of the probe. The successful combination of these two probe moieties with no perturbation of their individual detection introduces a platform for a versatile range of new correlative probes for bacteria.

Cost-Effective Live Cell Structured Illumination Microscopy with Video-Rate Imaging

ACS Photonics ◽  
2021 ◽  
Author(s):  
Alice Sandmeyer ◽  
Mario Lachetta ◽  
Hauke Sandmeyer ◽  
Wolfgang Hübner ◽  
Thomas Huser ◽  
...  
Keyword(s):  
Cost Effective ◽  
Live Cell ◽  
Structured Illumination ◽  
Structured Illumination Microscopy

scholarly journals A Genetically Encoded Isonitrile Lysine for Orthogonal Bioorthogonal Labeling Schemes

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4988
Author(s):  
Ágnes Szatmári ◽  
Gergely B. Cserép ◽  
Tibor Á. Molnár ◽  
Bianka Söveges ◽  
Adrienn Biró ◽  
...  
Keyword(s):  
Genetic Code ◽  
Mammalian Cells ◽  
Protein Structures ◽  
Cycloaddition Reaction ◽  
Membrane Receptors ◽  
Synthetic Dyes ◽  
Double Labeling ◽  
Click Reactions ◽  
Canonical Amino Acid ◽  
Genetic Code Expansion

Bioorthogonal click-reactions represent ideal means for labeling biomolecules selectively and specifically with suitable small synthetic dyes. Genetic code expansion (GCE) technology enables efficient site-selective installation of bioorthogonal handles onto proteins of interest (POIs). Incorporation of bioorthogonalized non-canonical amino acids is a minimally perturbing means of enabling the study of proteins in their native environment. The growing demand for the multiple modification of POIs has triggered the quest for developing orthogonal bioorthogonal reactions that allow simultaneous modification of biomolecules. The recently reported bioorthogonal [4 + 1] cycloaddition reaction of bulky tetrazines and sterically demanding isonitriles has prompted us to develop a non-canonical amino acid (ncAA) bearing a suitable isonitrile function. Herein we disclose the synthesis and genetic incorporation of this ncAA together with studies aiming at assessing the mutual orthogonality between its reaction with bulky tetrazines and the inverse electron demand Diels–Alder (IEDDA) reaction of bicyclononyne (BCN) and tetrazine. Results showed that the new ncAA, bulky-isonitrile-carbamate-lysine (BICK) is efficiently and specifically incorporated into proteins by genetic code expansion, and despite the slow [4 + 1] cycloaddition, enables the labeling of outer membrane receptors such as insulin receptor (IR) with a membrane-impermeable dye. Furthermore, double labeling of protein structures in live and fixed mammalian cells was achieved using the mutually orthogonal bioorthogonal IEDDA and [4 + 1] cycloaddition reaction pair, by introducing BICK through GCE and BCN through a HaloTag technique.

scholarly journals A technique for resolution assessment in blind-SIM experiments

2021 ◽  
Author(s):  
Imen Boujmil ◽  
Giancarlo Ruocco ◽  
Marco Leonetti
Keyword(s):  
High Resolution ◽  
Biological Sample ◽  
A Priori ◽  
Resolution Enhancement ◽  
Super Resolution ◽  
Experimental Setup ◽  
Wide Field ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Resolution Measurement

Super resolution techniques are an excellent alternative to wide field microscopy, providing high resolution also in (typically fragile) biological sample. Among the various super resolution techniques, Structured Illumination Microscopy (SIM) improve resolution by employing multiple illumination patterns to be deconvolved with a dedicated software. In the case of blind SIM techniques, unknown patterns, such as speckles, are used, thus providing super resolved images, nearly unaffected by aberrations with a simplified experimental setup. Scattering Assisted Imaging, a special blind SIM technique, exploits an illumination PSF (speckle grains size), smaller than the collection PSF (defined by the collection objectives), to surpass the typical SIM resolution enhancement. However, if SAI is used, it is very difficult to extract the resolution enhancement form a priori considerations. In this paper we propose a protocol and experimental setup for the resolution measurement, demonstrating the resolution enhancement for different collection PSF values.

scholarly journals Fringe optimization for structured illumination super-resolution microscope with digital micromirror device

2019 ◽  
Vol 12 (03) ◽  
pp. 1950014 ◽  
Author(s):  
Xibin Yang ◽  
Qian Zhu ◽  
Zhenglong Sun ◽  
Gang Wen ◽  
Xin Jin ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Low Cost ◽  
Super Resolution ◽  
Fluorescent Labeling ◽  
Live Cells ◽  
Digital Micromirror Device ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Wide Range ◽  
Fringe Patterns

Structured illumination microscopy (SIM) is a promising super-resolution technique for imaging subcellular structures and dynamics due to its compatibility with most commonly used fluorescent labeling methods. Structured illumination can be obtained by either laser interference or projection of fringe patterns. Here, we proposed a fringe projector composed of a compact multi-wavelength LEDs module and a digital micromirror device (DMD) which can be directly attached to most commercial inverted fluorescent microscopes and update it into a SIM system. The effects of the period and duty cycle of fringe patterns on the modulation depth of the structured light field were studied. With the optimized fringe pattern, [Formula: see text] resolution improvement could be obtained with high-end oil objectives. Multicolor imaging and dynamics of subcellular organelles in live cells were also demonstrated. Our method provides a low-cost solution for SIM setup to expand its wide range of applications to most research labs in the field of life science and medicine.

scholarly journals Live Cell Imaging of Bioorthogonally Labelled Proteins Generated With a Single Pyrrolysine tRNA Gene

2017 ◽  
Author(s):  
Noa Aloush ◽  
Tomer Schvartz ◽  
Andres I. König ◽  
Sarit Cohen ◽  
Eugene Brozgol ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Stop Codon ◽  
Signal To Noise Ratio ◽  
Trna Synthetase ◽  
Live Cell ◽  
Live Cells ◽  
Copy Numbers ◽  
Intracellular Proteins

ABSTRACTGenetic code expansion enables the incorporation of non-canonical amino acids (ncAAs) into expressed proteins. ncAAs are usually encoded by a stop codon that is decoded by an exogenous orthogonal aminoacyl tRNA synthetase and its cognate suppressor tRNA, such as the pyrrolysine synthetase/ pair. In such systems, stop codon suppression is dependent on the intracellular levels of the exogenous tRNA. Therefore, multiple copies of the tRNAPyl gene (PylT) are encoded to improve ncAA incorporation. However, certain applications in mammalian cells, such as live-cell imaging applications, where labelled tRNA contributes to background fluorescence, can benefit from the use of less invasive minimal expression systems. Accordingly, we studied the effect of tRNAPyl on live-cell fluorescence imaging of bioorthogonally-labelled intracellular proteins. We found that in COS7 cells, a decrease in PylT copy numbers had no measurable effect on protein expression levels. Importantly, reducing PylT copy numbers improved the quality of live-cells images by enhancing the signal-to-noise ratio and reducing an immobile tRNAPyl population. This enabled us to improve live cell imaging of bioorthogonally labelled intracellular proteins, and to simultaneously label two different proteins in a cell. Our results indicate that the number of introduced PylT genes can be minimized according to the transfected cell line, incorporated ncAA, and application.

scholarly journals Advances in High-Speed Structured Illumination Microscopy

2021 ◽  
Vol 9 ◽  
Author(s):  
Tianyu Zhao ◽  
Zhaojun Wang ◽  
Tongsheng Chen ◽  
Ming Lei ◽  
Baoli Yao ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
High Speed ◽  
Cell Imaging ◽  
Super Resolution ◽  
Live Cell ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Light Power ◽  
Recent Developments ◽  
Super Resolution Microscopy

Super-resolution microscopy surpasses the diffraction limit to enable the observation of the fine details in sub-cellular structures and their dynamics in diverse biological processes within living cells. Structured illumination microscopy (SIM) uses a relatively low illumination light power compared with other super-resolution microscopies and has great potential to meet the demands of live-cell imaging. However, the imaging acquisition and reconstruction speeds limit its further applications. In this article, recent developments all targeted at improving the overall speed of SIM are reviewed. These comprise both hardware and software improvements, which include a reduction in the number of raw images, GPU acceleration, deep learning and the spatial domain reconstruction. We also discuss the application of these developments in live-cell imaging.

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