scholarly journals Cryogenic Super-Resolution Fluorescence and Electron Microscopy Correlated at the Nanoscale

Author(s):  
Peter D. Dahlberg ◽  
W.E. Moerner

We review the emerging method of super-resolved cryogenic correlative light and electron microscopy (srCryoCLEM). Super-resolution (SR) fluorescence microscopy and cryogenic electron tomography (CET) are both powerful techniques for observing subcellular organization, but each approach has unique limitations. The combination of the two brings the single-molecule sensitivity and specificity of SR to the detailed cellular context and molecular scale resolution of CET. The resulting correlative data is more informative than the sum of its parts. The correlative images can be used to pinpoint the positions of fluorescently labeled proteins in the high-resolution context of CET with nanometer-scale precision and/or to identify proteins in electron-dense structures. The execution of srCryoCLEM is challenging and the approach is best described as a method that is still in its infancy with numerous technical challenges. In this review, we describe state-of-the-art srCryoCLEM experiments, discuss the most pressing challenges, and give a brief outlook on future applications. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 72 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

2021 ◽  
Author(s):  
Caio Vaz Rimoli ◽  
Cesar Augusto Valades Cruz ◽  
Valentina Curcio ◽  
Manos Mavrakis ◽  
Sophie Brasselet

Advances in single-molecule localization microscopy are providing unprecedented insights into the nanometer-scale organization of protein assemblies in cells and thus a powerful means for interrogating biological function. However, localization imaging alone does not contain information on protein conformation and orientation, which constitute additional key signatures of protein function. Here, we present a new microscopy method which combines for the first time Stochastic Optical Reconstruction Microscopy (STORM) super-resolution imaging with single molecule orientation and wobbling measurements using a four polarization-resolved image splitting scheme. This new method, called 4polar-STORM, allows us to determine both single molecule localization and orientation in 2D and to infer their 3D orientation, and is compatible with high labelling densities and thus ideally placed for the determination of the organization of dense protein assemblies in cells. We demonstrate the potential of this new method by studying the nanometer-scale organization of dense actin filament assemblies driving cell adhesion and motility, and reveal bimodal distributions of actin filament orientations in the lamellipodium, which were previously only observed in electron microscopy studies. 4polar-STORM is fully compatible with 3D localization schemes and amenable to live-cell observations, and thus promises to provide new functional readouts by enabling nanometer-scale studies of orientational dynamics in a cellular context.


Author(s):  
Rajarshi P. Ghosh ◽  
Barbara J. Meyer

Nuclei are central hubs for information processing in eukaryotic cells. The need to fit large genomes into small nuclei imposes severe restrictions on genome organization and the mechanisms that drive genome-wide regulatory processes. How a disordered polymer such as chromatin, which has vast heterogeneity in its DNA and histone modification profiles, folds into discernibly consistent patterns is a fundamental question in biology. Outstanding questions include how genomes are spatially and temporally organized to regulate cellular processes with high precision and whether genome organization is causally linked to transcription regulation. The advent of next-generation sequencing, super-resolution imaging, multiplexed fluorescent in situ hybridization, and single-molecule imaging in individual living cells has caused a resurgence in efforts to understand the spatiotemporal organization of the genome. In this review, we discuss structural and mechanistic properties of genome organization at different length scales and examine changes in higher-order chromatin organization during important developmental transitions. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Adeeba Fathima ◽  
César Augusto Quintana-Cataño ◽  
Christoph Heintze ◽  
Michael Schlierf

AbstractRecent advances in microscopy techniques enabled nanoscale discoveries in biology. In particular, electron microscopy reveals important cellular structures with nanometer resolution, yet it is hard, and sometimes impossible to resolve specific protein localizations. Super-resolution fluorescence microscopy techniques developed over the recent years allow for protein-specific localization with ~ 20 nm precision are overcoming this limitation, yet it remains challenging to place those in cells without a reference frame. Correlative light and electron microscopy (CLEM) approaches have been developed to place the fluorescence image in the context of a cellular structure. However, combining imaging methods such as super resolution microscopy and transmission electron microscopy necessitates a correlation using fiducial markers to locate the fluorescence on the structures visible in electron microscopy, with a measurable precision. Here, we investigated different fiducial markers for super-resolution CLEM (sCLEM) by evaluating their shape, intensity, stability and compatibility with photoactivatable fluorescent proteins as well as the electron density. We further carefully determined limitations of correlation accuracy. We found that spectrally-shifted FluoSpheres are well suited as fiducial markers for correlating single-molecule localization microscopy with transmission electron microscopy.


Platelets ◽  
2020 ◽  
Author(s):  
Zachary A. Matthay ◽  
Lucy Zumwinkle Kornblith

The knowledge gained through imaging platelets has formed the backbone of our understanding of their biology in health and disease. Early investigators relied on conventional light microscopy with limited resolution and were primarily able to identify the presence and basic morphology of platelets. The advent of high resolution technologies, in particular, electron microscopy, accelerated our understanding of the dynamics of platelet ultrastructure dramatically. Further refinements and improvements in our ability to localize and reliably identify platelet structures have included the use of immune-labeling techniques, correlative-fluorescence light and electron microscopy, and super-resolution microscopies. More recently, the expanded development and application of intravital microscopy in animal models has enhanced our knowledge of platelet functions and thrombus formation in vivo, as these experimental systems most closely replicate native biological environments. Emerging improvements in our ability to characterize platelets at the ultrastructural and organelle levels include the use of platelet cryogenic electron tomography with quantitative, unbiased imaging analysis, and the ability to genetically label platelet features with electron dense markers for analysis by electron microscopy.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dorothea Pinotsi ◽  
Simona Rodighiero ◽  
Silvia Campioni ◽  
Gabor Csucs

Abstract A number of new Correlative Light and Electron Microscopy approaches have been developed over the past years, offering the opportunity to combine the specificity and bio-compatibility of light microscopy with the high resolution achieved in electron microscopy. More recently, these approaches have taken one step further and also super-resolution light microscopy was combined with transmission or scanning electron microscopy. This combination usually requires moving the specimen between different imaging systems, an expensive set-up and relatively complicated imaging workflows. Here we present a way to overcome these difficulties by exploiting a commercially available wide-field fluorescence microscope integrated in the specimen chamber of a Scanning Electron Microscope (SEM) to perform correlative LM/EM studies. Super-resolution light microscopy was achieved by using a recently developed algorithm - the Super-Resolution Radial Fluctuations (SRRF) - to improve the resolution of diffraction limited fluorescent images. With this combination of hardware/software it is possible to obtain correlative super-resolution light and scanning electron microscopy images in an easy and fast way. The imaging workflow is described and demonstrated on fluorescently labelled amyloid fibrils, fibrillar protein aggregates linked to the onset of multiple neurodegenerative diseases, revealing information about their polymorphism.


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 ◽  
...  

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.


2019 ◽  
Vol 52 (37) ◽  
pp. 374003
Author(s):  
Christian A Wurm ◽  
Heinz Schwarz ◽  
Daniel C Jans ◽  
Dietmar Riedel ◽  
Bruno M Humbel ◽  
...  

1998 ◽  
Vol 4 (S2) ◽  
pp. 440-441
Author(s):  
Maryann E. Martone ◽  
Andrea Thor ◽  
Stephen J. Young ◽  
Mark H. Ellisman.

Light microscopic imaging has experienced a renaissance in the past decade or so, as new techniques for high resolution 3D light microscopy have become readily available. Light microscopic (LM) analysis of cellular details is desirable in many cases because of the flexibility of staining protocols, the ease of specimen preparation and the relatively large sample size that can be obtained compared to electron microscopic (EM) analysis. Despite these advantages, many light microscopic investigations require additional analysis at the electron microscopic level to resolve fine structural features.High voltage electron microscopy allows the use of relatively thick sections compared to conventional EM and provides the basis for excellent new methods to bridge the gap between microanatomical details revealed by LM and EM methods. When combined with electron tomography, investigators can derive accurate 3D data from these thicker specimens. Through the use of correlated light and electron microscopy, 3D reconstructions of large cellular or subcellular structures can be obtained with the confocal microscope,


Author(s):  
Minkyo Jung ◽  
Doory Kim ◽  
Ji Young Mun

Actin networks and actin-binding proteins (ABPs) are most abundant in the cytoskeleton of neurons. The function of ABPs in neurons is nucleation of actin polymerization, polymerization or depolymerization regulation, bundling of actin through crosslinking or stabilization, cargo movement along actin filaments, and anchoring of actin to other cellular components. In axons, ABP–actin interaction forms a dynamic, deep actin network, which regulates axon extension, guidance, axon branches, and synaptic structures. In dendrites, actin and ABPs are related to filopodia attenuation, spine formation, and synapse plasticity. ABP phosphorylation or mutation changes ABP–actin binding, which regulates axon or dendritic plasticity. In addition, hyperactive ABPs might also be expressed as aggregates of abnormal proteins in neurodegeneration. Those changes cause many neurological disorders. Here, we will review direct visualization of ABP and actin using various electron microscopy (EM) techniques, super resolution microscopy (SRM), and correlative light and electron microscopy (CLEM) with discussion of important ABPs in neuron.


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