scholarly journals Blinking fluorescent probes for tubulin nanoscopy in living and fixed cells

2021 ◽  
Author(s):  
Ruta Gerasimaite ◽  
Jonas Bucevicius ◽  
Kamila A. Kiszka ◽  
Georgij Kostiuk ◽  
Tanja Koenen ◽  
...  

Here we report a small molecule probe for single molecule localisation microscopy (SMLM) of tubulin in living and fixed cells. We explored a series of constructs composed of taxanes and spontaneously blinking far-red dye hydroxymethyl silicon-rhodamine (HMSiR). We found that the linker length profoundly affects the probe permeability and off-targeting. The best performing probe, HMSiR-tubulin, is composed of cabazitaxel and 6'-regioisomer of HMSiR bridged by a C6 linker. Microtubule diameters of <50 nm can be routinely measured in SMLM experiments on living and fixed cells. HMSiR-tubulin also performs well in 3D stimulated emission depletion (STED) microscopy, allowing a complementary use of both nanoscopy methods for investigating microtubule functions in living cells.

2018 ◽  
Vol 218 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Lena K. Schroeder ◽  
Andrew E.S. Barentine ◽  
Holly Merta ◽  
Sarah Schweighofer ◽  
Yongdeng Zhang ◽  
...  

The endoplasmic reticulum (ER) is composed of interconnected membrane sheets and tubules. Superresolution microscopy recently revealed densely packed, rapidly moving ER tubules mistaken for sheets by conventional light microscopy, highlighting the importance of revisiting classical views of ER structure with high spatiotemporal resolution in living cells. In this study, we use live-cell stimulated emission depletion (STED) microscopy to survey the architecture of the ER at 50-nm resolution. We determine the nanoscale dimensions of ER tubules and sheets for the first time in living cells. We demonstrate that ER sheets contain highly dynamic, subdiffraction-sized holes, which we call nanoholes, that coexist with uniform sheet regions. Reticulon family members localize to curved edges of holes within sheets and are required for their formation. The luminal tether Climp63 and microtubule cytoskeleton modulate their nanoscale dynamics and organization. Thus, by providing the first quantitative analysis of ER membrane structure and dynamics at the nanoscale, our work reveals that the ER in living cells is not limited to uniform sheets and tubules; instead, we suggest the ER contains a continuum of membrane structures that includes dynamic nanoholes in sheets as well as clustered tubules.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Erika Günther ◽  
André Klauß ◽  
Mauricio Toro-Nahuelpan ◽  
Dirk Schüler ◽  
Carsten Hille ◽  
...  

AbstractProtein interaction and protein imaging strongly benefit from the advancements in time-resolved and superresolution fluorescence microscopic techniques. However, the techniques were typically applied separately and ex vivo because of technical challenges and the absence of suitable fluorescent protein pairs. Here, we show correlative in vivo fluorescence lifetime imaging microscopy Förster resonance energy transfer (FLIM-FRET) and stimulated emission depletion (STED) microscopy to unravel protein mechanics and structure in living cells. We use magnetotactic bacteria as a model system where two proteins, MamJ and MamK, are used to assemble magnetic particles called magnetosomes. The filament polymerizes out of MamK and the magnetosomes are connected via the linker MamJ. Our system reveals that bacterial filamentous structures are more fragile than the connection of biomineralized particles to this filament. More importantly, we anticipate the technique to find wide applicability for the study and quantification of biological processes in living cells and at high resolution.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jelle Storterboom ◽  
Martina Barbiero ◽  
Stefania Castelletto ◽  
Min Gu

AbstractThe negatively charged nitrogen-vacancy ($${\text{NV}}^{ - }$$ NV - ) centre in nanodiamonds (NDs) has been recently studied for applications in cellular imaging due to its better photo-stability and biocompatibility if compared to other fluorophores. Super-resolution imaging achieving 20-nm resolution of $${\text{NV}}^{ - }$$ NV - in NDs has been proved over the years using sub-diffraction limited imaging approaches such as single molecule stochastic localisation microscopy and stimulated emission depletion microscopy. Here we show the first demonstration of ground-state depletion (GSD) nanoscopy of these centres in NDs using three beams, a probe beam, a depletion beam and a reset beam. The depletion beam at 638 nm forces the $${\text{NV}}^{ - }$$ NV - centres to the metastable dark state everywhere but in the local minimum, while a Gaussian beam at 594 nm probes the $${\text{NV}}^{ - }$$ NV - centres and a 488-nm reset beam is used to repopulate the excited state. Super-resolution imaging of a single $${\text{NV}}^{ - }$$ NV - centre with a full width at half maximum of 36 nm is demonstrated, and two adjacent $${\text{NV}}^{ - }$$ NV - centres separated by 72 nm are resolved. GSD microscopy is here applied to $${\text{NV}}^{ - }$$ NV - in NDs with a much lower optical power compared to bulk diamond. This work demonstrates the need to control the NDs nitrogen concentration to tailor their application in super-resolution imaging methods and paves the way for studies of $${\text{NV}}^{ - }$$ NV - in NDs’ nanoscale interactions.


2021 ◽  
Author(s):  
gangwei jiang ◽  
Tian-Bing Ren ◽  
Elisa D’Este ◽  
mengyi xiong ◽  
Bin Xiong ◽  
...  

Abstract The quality and application of super-resolution fluorescence imaging greatly lie in the properties of fluorescent probes. However, conventional fluorophores in a cellular environment often suffer from low brightness, poor photostability, and short Stokes shift (< 30 nm). Here we report a synergistic strategy to simultaneously improve such properties of regular fluorophores. Introduction of quinoxaline motif with fine-tuned electron density to conventional rhodamines generates new dyes with vibronic structure and inhibited twisted-intramolecular-charge-transfer (TICT) formation synchronously, thus increasing the brightness and photostability as well as Stokes shift. The new fluorophore BDQF-6 exhibits around twofold greater brightness (ε × Φ = 6.6 × 104 L·mol− 1·cm− 1) and Stokes shift (56 nm) than its parental fluorophore, Rhodamine B. Importantly, in Stimulated Emission Depletion (STED) microscopy, BDQF-6 derived probe possesses a superior photostability and thus renders threefold more frames than carbopyronine- and JF608-based probes, known as photostable fluorophores for STED imaging. More BDQF-6 derivatives were developed next, allowing us to perform wash-free organelles (mitochondria and lysosome) staining and protein labeling with ultrahigh signal-to-noise ratios (up to 106 folds) in confocal and STED microscopy of live cells, or two-photon and 3D STED microscopy of fixed cells. Furthermore, the strategy was well generalized to different types of dyes (pyronin, rhodol, coumarin, and Boranil), offering a new class of bright and photostable fluorescent probes with long Stokes shift (up to 136 nm) for bioimaging and biosensing.


2019 ◽  
Author(s):  
Esther Braselmann ◽  
Timothy J. Stasevich ◽  
Kenneth Lyon ◽  
Robert T. Batey ◽  
Amy E. Palmer

AbstractLabeling and tracking biomolecules with fluorescent probes on the single molecule level enables quantitative insights into their dynamics in living cells. We previously developed Riboglow, a platform to label RNAs in live mammalian cells, consisting of a short RNA tag and a small organic probe that increases fluorescence upon binding RNA. Here, we demonstrate that Riboglow is capable of detecting and tracking single RNA molecules. We benchmark RNA tracking by comparing results with the established MS2 RNA tagging system. To demonstrate versatility of Riboglow, we assay translation on the single molecule level, where the translated mRNA is tagged with Riboglow and the nascent polypeptide is labeled with a fluorescent antibody. The growing effort to investigate RNA biology on the single molecule level requires sophisticated and diverse fluorescent probes for multiplexed, multi-color labeling of biomolecules of interest, and we present Riboglow as a new member in this toolbox.


Author(s):  
Ruohan Xu ◽  
Yanzi Xu ◽  
Zhi Wang ◽  
Yu Zhou ◽  
Dongfeng Dang ◽  
...  

: Stimulated emission depletion (STED) microscopy has become a useful tool to visualize and dynamic monitor at an ultra-high resolution in both biological research and material science. For STED technology, fluorescent probes are irreplaceable in imaging process. Among them, organic fluorescent probes exhibit characteristics of superior photo-stability, high brightness, large Stokes' shifts and excellent biocompability, thus resulting in wide applications in STED microscopy. Based on this consideration, in this review, the recent advances on organic fluorescent probes, including typical organic fluorescent probes, aggregation-induced emission luminogens (AIEgens), polymer dots and other nanoparticles, are introduced. The applications of organic fluorescent probes in biological imaging, such as live-cell, tissue and in-vivo imaging, and also material monitoring on the nanometer scale by using STED microscopy are then included. Based on these results, the rules to design new materials for STED microscopy are provided to enhance their imaging performance and then further enrich their real-world applications in future research.


2020 ◽  
Vol 1127 ◽  
pp. 295-302
Author(s):  
Ting Cao ◽  
Zhidong Teng ◽  
Lei Zheng ◽  
Jing Qian ◽  
Hong Ma ◽  
...  

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