scholarly journals Correlative SMLM and electron tomography reveals endosome nanoscale domains

2019 ◽  
Author(s):  
Christian Franke ◽  
Urska Repnik ◽  
Sandra Segeletz ◽  
Nicolas Brouilly ◽  
Yannis Kalaidzidis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Single Molecule ◽  
Electron Tomography ◽  
Small Gtpase ◽  
Molecular Organization ◽  
Functional Domains ◽  
Localization Microscopy ◽  
Early Endosomes ◽  
Single Molecule Localization Microscopy

AbstractMany cellular organelles, including endosomes, show compartmentalization into distinct functional domains, which however cannot be resolved by diffraction-limited light microscopy. Single molecule localization microscopy (SMLM) offers nanoscale resolution but data interpretation is often inconclusive when the ultrastructural context is missing. Correlative light electron microscopy (CLEM) combining SMLM with electron microscopy (EM) enables correlation of functional sub-domains of organelles in relation to their underlying ultrastructure at nanometer resolution. However, the specific demands for EM sample preparation and the requirements for fluorescent single-molecule photo-switching are opposed. Here, we developed a novel superCLEM workflow that combines triple-colour SMLM (dSTORM & PALM) and electron tomography using semi-thin Tokuyasu thawed cryosections. We applied the superCLEM approach to directly visualize nanoscale compartmentalization of endosomes in HeLa cells. Internalized, fluorescently labelled Transferrin and EGF were resolved into morphologically distinct domains within the same endosome. We found that the small GTPase Rab5 is organized in nano-domains on the globular part of early endosomes. The simultaneous visualization of several proteins in functionally distinct endosomal sub-compartments demonstrates the potential of superCLEM to link the ultrastructure of organelles with their molecular organization at nanoscale resolution.SynopsisSuborganelle compartmentalization cannot be resolved by diffraction limited light microscopy and not interpreted without knowledge of the underlying ultrastructure. This work shows a novel superCLEM workflow that combines multi-colour single-molecule localization-microscopy with electron tomography to map several functional domains on early endosomes. superCLEM reveals that the small GTPase Rab5 is organized in nano-domains largely devoid from cargo molecules Transferrin and EGF and opens new possibilities to perform structure-function analysis of organelles at the nanoscale.

Advances in Correlative Single-Molecule Localization Microscopy and Electron Microscopy

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ulrike Endesfelder
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Single Molecule ◽  
Light And Electron Microscopy ◽  
Fluorescence Labeling ◽  
Localization Microscopy ◽  
Fluorescence Light Microscopy ◽  
Fluorescence Light ◽  
And Function ◽  
Single Molecule Localization Microscopy

AbstractDuring the last few decades, correlative fluorescence light and electron microscopy (FLM-EM) has gained increased interest in the life sciences concomitant with the advent of fluorescence light microscopy. It has become, accompanied by numerous developments in both techniques, an important tool to study bio-cellular structure and function as it combines the specificity of fluorescence labeling with the high structural resolution and cellular context information given by the EM images. Having the recently introduced single-molecule localization microscopy techniques (SMLM) at hand, FLM-EM can now make use of improved fluorescence light microscopy resolution, single-molecule sensitivity and quantification strategies. Here, currently used methods for correlative SMLM and EM including the special requirements in sample preparation and imaging routines are summarized and an outlook on remaining challenges concerning methods and instrumentation is provided.

scholarly journals Cost-efficient nanoscopy reveals nanoscale architecture of liver cells and platelets

Nanophotonics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 1299-1313 ◽  
Author(s):  
Hong Mao ◽  
Robin Diekmann ◽  
Hai Po H. Liang ◽  
Victoria C. Cogger ◽  
David G. Le Couteur ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Single Molecule ◽  
Nanometer Scale ◽  
Color Channel ◽  
Liver Sinusoidal Endothelial Cells ◽  
Localization Microscopy ◽  
Cost Efficient ◽  
Core Facilities ◽  
Single Molecule Localization Microscopy

AbstractSingle-molecule localization microscopy (SMLM) provides a powerful toolkit to specifically resolve intracellular structures on the nanometer scale, even approaching resolution classically reserved for electron microscopy (EM). Although instruments for SMLM are technically simple to implement, researchers tend to stick to commercial microscopes for SMLM implementations. Here we report the construction and use of a “custom-built” multi-color channel SMLM system to study liver sinusoidal endothelial cells (LSECs) and platelets, which costs significantly less than a commercial system. This microscope allows the introduction of highly affordable and low-maintenance SMLM hardware and methods to laboratories that, for example, lack access to core facilities housing high-end commercial microscopes for SMLM and EM. Using our custom-built microscope and freely available software from image acquisition to analysis, we image LSECs and platelets with lateral resolution down to about 50 nm. Furthermore, we use this microscope to examine the effect of drugs and toxins on cellular morphology.

scholarly journals Molecular resolution imaging by post-labeling expansion single-molecule localization microscopy (Ex-SMLM)

2020 ◽  
Author(s):  
Fabian U. Zwettler ◽  
Sebastian Reinhard ◽  
Davide Gambarotto ◽  
Toby D. M. Bell ◽  
Virginie Hamel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Molecule ◽  
Super Resolution ◽  
Reference Structure ◽  
Positional Error ◽  
Localization Microscopy ◽  
Resolution Imaging ◽  
Endogenous Proteins ◽  
Super Resolution Microscopy ◽  
Single Molecule Localization Microscopy

AbstractExpansion microscopy (ExM) enables super-resolution fluorescence imaging of physically expanded biological samples with conventional microscopes. By combining expansion microscopy (ExM) with single-molecule localization microscopy (SMLM) it is potentially possible to approach the resolution of electron microscopy. However, current attempts to combine both methods remained challenging because of protein and fluorophore loss during digestion or denaturation, gelation, and the incompatibility of expanded polyelectrolyte hydrogels with photoswitching buffers. Here we show that re-embedding of expanded hydrogels enables dSTORM imaging of expanded samples and demonstrate that post-labeling ExM resolves the current limitations of super-resolution microscopy. Using microtubules as a reference structure and centrioles, we demonstrate that post-labeling Ex-SMLM preserves ultrastructural details, improves the labeling efficiency and reduces the positional error arising from linking fluorophores into the gel thus paving the way for super-resolution imaging of immunolabeled endogenous proteins with true molecular resolution.

scholarly journals Correlative single‐molecule localization microscopy and electron tomography reveals endosome nanoscale domains

Traffic ◽  
2019 ◽  
Vol 20 (8) ◽  
pp. 601-617 ◽  
Author(s):  
Christian Franke ◽  
Urska Repnik ◽  
Sandra Segeletz ◽  
Nicolas Brouilly ◽  
Yannis Kalaidzidis ◽  
...  
Keyword(s):  
Single Molecule ◽  
Electron Tomography ◽  
Localization Microscopy ◽  
Single Molecule Localization Microscopy

scholarly journals Targeted volumetric single-molecule localization microscopy of defined presynaptic structures in brain sections

2019 ◽  
Author(s):  
Martin Pauli ◽  
Mila M. Paul ◽  
Sven Proppert ◽  
Marzieh Sharifi ◽  
Felix Repp ◽  
...  
Keyword(s):  
Single Molecule ◽  
Mossy Fiber ◽  
Three Dimensional ◽  
Brain Regions ◽  
Molecular Organization ◽  
Localization Microscopy ◽  
Stochastic Optical Reconstruction Microscopy ◽  
Optical Reconstruction ◽  
Axial Scanning ◽  
Single Molecule Localization Microscopy

ABSTRACTRevealing the molecular organization of anatomically precisely defined brain regions is necessary for the refined understanding of synaptic plasticity. Although, three-dimensional (3D) single-molecule localization microscopy can provide the required molecular resolution, single-molecule imaging more than a few micrometers deep into tissue remains challenging. To quantify presynaptic active zones (AZ) of entire, large, conditional detonator hippocampal mossy fiber (MF) boutons with diameters as large as 10 µm, we developed a method for aberration-free volumetricdirectstochastic optical reconstruction microscopy (dSTORM). An optimized protocol for fast repeated axial scanning and efficient sequential labeling of the AZ scaffold Bassoon and membrane bound GFP with Alexa Fluor 647 enables 3D-dSTORM imaging of 25 µm thick mouse brain sections and assignment of AZs to specific neuronal substructures. Quantitative data analysis revealed large differences in Bassoon cluster size and density for distinct hippocampal regions with largest clusters in MF boutons.

scholarly journals Targeted volumetric single-molecule localization microscopy of defined presynaptic structures in brain sections

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Martin Pauli ◽  
Mila M. Paul ◽  
Sven Proppert ◽  
Achmed Mrestani ◽  
Marzieh Sharifi ◽  
...  
Keyword(s):  
Single Molecule ◽  
Mossy Fiber ◽  
Three Dimensional ◽  
Brain Regions ◽  
Molecular Organization ◽  
Localization Microscopy ◽  
Stochastic Optical Reconstruction Microscopy ◽  
Optical Reconstruction ◽  
Axial Scanning ◽  
Single Molecule Localization Microscopy

AbstractRevealing the molecular organization of anatomically precisely defined brain regions is necessary for refined understanding of synaptic plasticity. Although three-dimensional (3D) single-molecule localization microscopy can provide the required resolution, imaging more than a few micrometers deep into tissue remains challenging. To quantify presynaptic active zones (AZ) of entire, large, conditional detonator hippocampal mossy fiber (MF) boutons with diameters as large as 10 µm, we developed a method for targeted volumetric direct stochastic optical reconstruction microscopy (dSTORM). An optimized protocol for fast repeated axial scanning and efficient sequential labeling of the AZ scaffold Bassoon and membrane bound GFP with Alexa Fluor 647 enabled 3D-dSTORM imaging of 25 µm thick mouse brain sections and assignment of AZs to specific neuronal substructures. Quantitative data analysis revealed large differences in Bassoon cluster size and density for distinct hippocampal regions with largest clusters in MF boutons.

Single-Molecule Imaging of Active Mitochondrial Nitroreductases using a Photo-Crosslinking Fluorescent Sensor

2019 ◽  
Author(s):  
Zacharias Thiel ◽  
Pablo Rivera-Fuentes
Keyword(s):  
Subcellular Localization ◽  
Fluorescent Probe ◽  
Single Molecule ◽  
Mammalian Cells ◽  
Fluorescent Sensor ◽  
Biological Functions ◽  
Localization Microscopy ◽  
Drug Activation ◽  
Nitroreductase Activity ◽  
Single Molecule Localization Microscopy

Many biomacromolecules are known to cluster in microdomains with specific subcellular localization. In the case of enzymes, this clustering greatly defines their biological functions. Nitroreductases are enzymes capable of reducing nitro groups to amines and play a role in detoxification and pro-drug activation. Although nitroreductase activity has been detected in mammalian cells, the subcellular localization of this activity remains incompletely characterized. Here, we report a fluorescent probe that enables super-resolved imaging of pools of nitroreductase activity within mitochondria. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. In combination with a general photoactivatable marker of mitochondria, we performed two-color, threedimensional, single-molecule localization microscopy. These experiments allowed us to image the sub-mitochondrial organization of microdomains of nitroreductase activity.<br>

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