scholarly journals Label-free and live cell imaging by interferometric scattering microscopy

2018 ◽  
Vol 9 (10) ◽  
pp. 2690-2697 ◽  
Author(s):  
Jin-Sung Park ◽  
Il-Buem Lee ◽  
Hyeon-Min Moon ◽  
Jong-Hyeon Joo ◽  
Kyoung-Hoon Kim ◽  
...  

Despite recent remarkable advances in microscopic techniques, it still remains very challenging to directly observe the complex structure of cytoplasmic organelles in live cells without a fluorescent label.

2012 ◽  
Vol 102 (2) ◽  
pp. 360-368 ◽  
Author(s):  
Katharina Klein ◽  
Alexander M. Gigler ◽  
Thomas Aschenbrenner ◽  
Roberto Monetti ◽  
Wolfram Bunk ◽  
...  

2021 ◽  
Author(s):  
Y. Bousmah ◽  
H. Valenta ◽  
G. Bertolin ◽  
U. Singh ◽  
V. Nicolas ◽  
...  

AbstractYellow fluorescent proteins (YFP) are widely used as optical reporters in Förster Resonance Energy Transfer (FRET) based biosensors. Although great improvements have been done, the sensitivity of the biosensors is still limited by the low photostability and the poor fluorescence performances of YFPs at acidic pHs. In fact, today, there is no yellow variant derived from the EYFP with a pK1/2 below ∼5.5. Here, we characterize a new yellow fluorescent protein, tdLanYFP, derived from the tetrameric protein from the cephalochordate B. lanceolatum, LanYFP. With a quantum yield of 0.92 and an extinction coefficient of 133 000 mol−1.L.cm−1, it is, to our knowledge, the brightest dimeric fluorescent protein available, and brighter than most of the monomeric YFPs. Contrasting with EYFP and its derivatives, tdLanYFP has a very high photostability in vitro and preserves this property in live cells. As a consequence, tdLanYFP allows the imaging of cellular structures with sub-diffraction resolution with STED nanoscopy. We also demonstrate that the combination of high brightness and strong photostability is compatible with the use of spectro-microscopies in single molecule regimes. Its very low pK1/2 of 3.9 makes tdLanYFP an excellent tag even at acidic pHs. Finally, we show that tdLanYFP can be a FRET partner either as donor or acceptor in different biosensing modalities. Altogether, these assets make tdLanYFPa very attractive yellow fluorescent protein for long-term or single-molecule live-cell imaging that is also suitable for FRET experiment including at acidic pH.


2020 ◽  
Author(s):  
Patricia A. Clow ◽  
Nathaniel Jillette ◽  
Jacqueline J. Zhu ◽  
Albert W. Cheng

AbstractThree-dimensional (3D) structures of the genome are dynamic, heterogeneous and functionally important. Live cell imaging has become the leading method for chromatin dynamics tracking. However, existing CRISPR- and TALE-based genomic labeling techniques have been hampered by laborious protocols and low signal-to-noise ratios (SNRs), and are thus mostly applicable to repetitive sequences. Here, we report a versatile CRISPR/Casilio-based imaging method, with an enhanced SNR, that allows for one nonrepetitive genomic locus to be labeled using a single sgRNA. We constructed Casilio dual-color probes to visualize the dynamic interactions of cohesin-bound elements in single live cells. By forming a binary sequence of multiple Casilio probes (PISCES) across a continuous stretch of DNA, we track the dynamic 3D folding of a 74kb genomic region over time. This method offers unprecedented resolution and scalability for delineating the dynamic 4D nucleome.One Sentence SummaryCasilio enables multiplexed live cell imaging of nonrepetitive DNA loci for illuminating the real-time dynamics of genome structures.


2014 ◽  
Vol 24 (30) ◽  
pp. 4795-4795 ◽  
Author(s):  
Aaron M. Keller ◽  
Yagnaseni Ghosh ◽  
Matthew S. DeVore ◽  
Mary E. Phipps ◽  
Michael H. Stewart ◽  
...  

2018 ◽  
Author(s):  
Livia V. Bayer ◽  
Omar S. Omar ◽  
Diana P. Bratu ◽  
Irina E. Catrina

ABSTRACTMolecular beacons are nucleic acid oligomers labeled with a fluorophore and a quencher that fold in a hairpin-shaped structure, which fluoresce only when bound to their target RNA. They are used for the visualization of endogenous mRNAs in live cells. Here, we report a Python program (PinMol) that designs molecular beacons best suited for live cell imaging by using structural information from secondary structures of the target RNA, predicted via energy minimization approaches. PinMol takes into account the accessibility of the targeted regions, as well as the inter- and intramolecular interactions of each selected probe. To demonstrate its applicability, we synthesized an oskar mRNA-specific molecular beacon (osk1236), which is selected by PinMol to target a more accessible region than a manually designed oskar-specific molecular beacon (osk2216). We previously demonstrated osk2216 to be efficient in detecting oskar mRNA in in vivo experiments. Here, we show that osk1236 outperformed osk2216 in live cell imaging experiments.


2017 ◽  
Author(s):  
Noa Aloush ◽  
Tomer Schvartz ◽  
Andres I. König ◽  
Sarit Cohen ◽  
Eugene Brozgol ◽  
...  

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.


2017 ◽  
Author(s):  
Doyeon Kim ◽  
SangYun Lee ◽  
Moosung Lee ◽  
JunTaek Oh ◽  
Su-A Yang ◽  
...  

AbstractLive cell imaging provides essential information in the investigation of cell biology and related pathophysiology. Refractive index (RI) can serve as intrinsic optical imaging contrast for 3-D label-free and quantitative live cell imaging, and provide invaluable information to understand various dynamics of cells and tissues for the study of numerous fields. Recently significant advances have been made in imaging methods and analysis approaches utilizing RI, which are now being transferred to biological and medical research fields, providing novel approaches to investigate the pathophysiology of cells. To provide insight how RI can be used as an imaging contrast for imaging of biological specimens, here we provide the basic principle of RI-based imaging techniques and summarize recent progress on applications, ranging from microbiology, hematology, infectious diseases, hematology, and histopathology.


Author(s):  
Raji Atchudan ◽  
Thomas Nesakumar Jebakumar Immanuel Edison ◽  
Suguna Perumal ◽  
N. Clament Sagaya Selvam ◽  
Yong Rok Lee

2019 ◽  
Author(s):  
B. Kemper ◽  
A. Bauwens ◽  
D. Bettenworth ◽  
M. Götte ◽  
B. Greve ◽  
...  

2016 ◽  
Vol 12 (1) ◽  
pp. 1600037 ◽  
Author(s):  
Batirtze Prats Mateu ◽  
Eva Harreither ◽  
Markus Schosserer ◽  
Verena Puxbaum ◽  
Elisabeth Gludovacz ◽  
...  

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