scholarly journals Second Harmonic Super-resolution Microscopy for Quantification of mRNA at Single Copy Sensitivity

ACS Nano ◽  
2014 ◽  
Vol 8 (12) ◽  
pp. 12418-12427 ◽  
Author(s):  
Jing Liu ◽  
Il-Hoon Cho ◽  
Yi Cui ◽  
Joseph Irudayaraj
2014 ◽  
Author(s):  
Jing Liu ◽  
Il-Hoon Cho ◽  
Ulhas Kadam ◽  
Joseph Irudayaraj

2021 ◽  
Author(s):  
Michal Franek ◽  
Agata Kilar ◽  
Petr Fojtík ◽  
Marie Olšinová ◽  
Aleš Benda ◽  
...  

Analysis of histone variants and epigenetic marks is dominated by genome-wide approaches in the form of chromatin immunoprecipitation-sequencing (ChIP-seq) and related methods. While uncontested in their value for single-copy genes, mapping the chromatin of DNA repeats is problematic for biochemical techniques based on averaging cell populations or high number of repeats in a single cell analysis. Extending chromatin and DNA fibers allows us to study the epigenetics of individual repeats in their specific chromosomal context and thus constitutes an important tool for a wholesome understanding of the epigenetic organization of genomes. We present that using an optimized fiber extension protocol is essential to obtain more reproducible data, where the clustering of fibers is minimized. We also demonstrate that applying super-resolution microscopy is important to reliably evaluate the distribution of histone modifications on individual fibers. Furthermore, we introduce a custom script to analyse methylation levels on DNA fibers and apply it to map the methylation of telomeres, ribosomal genes and centromeres.


2013 ◽  
Vol 36 (1-2) ◽  
pp. 5-17 ◽  
Author(s):  
Luke Fritzky ◽  
David Lagunoff

It requires a good deal of will power to resist hyperbole in considering the advances that have been achieved in fluorescence microscopy in the last 25 years. Our effort has been to survey the modalities of microscopic fluorescence imaging available to cell biologists and perhaps useful for diagnostic pathologists. The gamut extends from established confocal laser scanning through multiphoton and TIRF to the emerging technologies of super-resolution microscopy that breech the Abbé limit of resolution. Also considered are the recent innovations in structured and light sheet illumination, the use of FRET and molecular beacons that exploit specific characteristics of designer fluorescent proteins, fluorescence speckles, and second harmonic generation for native anisometric structures like collagen, microtubules and sarcomeres.


Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 42-51
Author(s):  
S. S. Ryabichko ◽  
◽  
A. N. Ibragimov ◽  
L. A. Lebedeva ◽  
E. N. Kozlov ◽  
...  

2019 ◽  
Author(s):  
Jeffrey Chang ◽  
Matthew Romei ◽  
Steven Boxer

<p>Double-bond photoisomerization in molecules such as the green fluorescent protein (GFP) chromophore can occur either via a volume-demanding one-bond-flip pathway or via a volume-conserving hula-twist pathway. Understanding the factors that determine the pathway of photoisomerization would inform the rational design of photoswitchable GFPs as improved tools for super-resolution microscopy. In this communication, we reveal the photoisomerization pathway of a photoswitchable GFP, rsEGFP2, by solving crystal structures of <i>cis</i> and <i>trans</i> rsEGFP2 containing a monochlorinated chromophore. The position of the chlorine substituent in the <i>trans</i> state breaks the symmetry of the phenolate ring of the chromophore and allows us to distinguish the two pathways. Surprisingly, we find that the pathway depends on the arrangement of protein monomers within the crystal lattice: in a looser packing, the one-bond-flip occurs, whereas in a tighter packing (7% smaller unit cell size), the hula-twist occurs.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p> <p> </p>


2015 ◽  
Vol 9 (1-2) ◽  
pp. 161-170 ◽  
Author(s):  
Martin Lehmann ◽  
Gregor Lichtner ◽  
Haider Klenz ◽  
Jan Schmoranzer

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