Ptychography: use of quantitative phase information for high-contrast label free time-lapse imaging of living cells

2014 ◽  
Author(s):  
Rakesh Suman ◽  
Peter O'Toole
Keyword(s):  
Time Lapse ◽  
Living Cells ◽  
Free Time ◽  
High Contrast ◽  
Label Free ◽  
Phase Information ◽  
Quantitative Phase ◽  
Time Lapse Imaging

scholarly journals Cytoplasmic dynamics of myosin IIA and IIB: spatial ‘sorting’ of isoforms in locomoting cells

1998 ◽  
Vol 111 (15) ◽  
pp. 2085-2095 ◽  
Author(s):  
J. Kolega
Keyword(s):  
Cultured Cells ◽  
Myosin Ii ◽  
Cell Movement ◽  
Leading Edge ◽  
Time Lapse ◽  
Living Cells ◽  
Immunofluorescence Staining ◽  
Spatial Sorting ◽  
Time Lapse Imaging

Different isoforms of non-muscle myosin II have different distributions in vivo, even within individual cells. In order to understand how these different distributions arise, the distribution and dynamics of non-muscle myosins IIA and myosin IIB were examined in cultured cells using immunofluorescence staining and time-lapse imaging of fluorescent analogs. Cultured bovine aortic endothelia contained both myosins IIA and IIB. Both isoforms distributed along stress fibers, in linear or punctate aggregates within lamellipodia, and diffusely around the nucleus. However, the A isoform was preferentially located toward the leading edge of migrating cells when compared with myosin IIB by double immunofluorescence staining. Conversely, the B isoform was enriched in structures at the cells' trailing edges. When fluorescent analogs of the two isoforms were co-injected into living cells, the injected myosins distributed with the same disparate localizations as endogenous myosins IIA and IIB. This indicated that the ability of the myosins to ‘sort’ within the cytoplasm is intrinsic to the proteins themselves, and not a result of localized synthesis or degradation. Furthermore, time-lapse imaging of injected analogs in living cells revealed differences in the rates at which the two isoforms rearranged during cell movement. The A isoform appeared in newly formed structures more rapidly than the B isoform, and was also lost more rapidly when structures disassembled. These observations suggest that the different localizations of myosins IIA and IIB reflect different rates at which the isoforms transit through assembly, movement and disassembly within the cell. The relative proportions of different myosin II isoforms within a particular cell type may determine the lifetimes of various myosin II-based structures in that cell.

scholarly journals Rapid, label-free classification of tumor-reactive T cell killing with quantitative phase microscopy and machine learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diane N. H. Kim ◽  
Alexander A. Lim ◽  
Michael A. Teitell
Keyword(s):  
Machine Learning ◽  
T Cell ◽  
Time Lapse ◽  
Cell Receptor ◽  
Model System ◽  
Cell Killing ◽  
Label Free ◽  
Receptor Model ◽  
Quantitative Phase ◽  
Phase Microscopy

AbstractQuantitative phase microscopy (QPM) enables studies of living biological systems without exogenous labels. To increase the utility of QPM, machine-learning methods have been adapted to extract additional information from the quantitative phase data. Previous QPM approaches focused on fluid flow systems or time-lapse images that provide high throughput data for cells at single time points, or of time-lapse images that require delayed post-experiment analyses, respectively. To date, QPM studies have not imaged specific cells over time with rapid, concurrent analyses during image acquisition. In order to study biological phenomena or cellular interactions over time, efficient time-dependent methods that automatically and rapidly identify events of interest are desirable. Here, we present an approach that combines QPM and machine learning to identify tumor-reactive T cell killing of adherent cancer cells rapidly, which could be used for identifying and isolating novel T cells and/or their T cell receptors for studies in cancer immunotherapy. We demonstrate the utility of this method by machine learning model training and validation studies using one melanoma-cognate T cell receptor model system, followed by high classification accuracy in identifying T cell killing in an additional, independent melanoma-cognate T cell receptor model system. This general approach could be useful for studying additional biological systems under label-free conditions over extended periods of examination.

scholarly journals Spatial distribution and functional significance of activated vinculin in living cells

2005 ◽  
Vol 169 (3) ◽  
pp. 459-470 ◽  
Author(s):  
Hui Chen ◽  
Daniel M. Cohen ◽  
Dilshad M. Choudhury ◽  
Noriyuki Kioka ◽  
Susan W. Craig
Keyword(s):  
Conformational Change ◽  
Direct Evidence ◽  
Resonance Energy Transfer ◽  
Focal Adhesions ◽  
Resonance Energy ◽  
Time Lapse ◽  
Living Cells ◽  
Actin Binding ◽  
Binding Conformation ◽  
Time Lapse Imaging

Conformational change is believed to be important to vinculin's function at sites of cell adhesion. However, nothing is known about vinculin's conformation in living cells. Using a Forster resonance energy transfer probe that reports on changes in vinculin's conformation, we find that vinculin is in the actin-binding conformation in a peripheral band of adhesive puncta in spreading cells. However, in fully spread cells with established polarity, vinculin's conformation is variable at focal adhesions. Time-lapse imaging reveals a gradient of conformational change that precedes loss of vinculin from focal adhesions in retracting regions. At stable or protruding regions, recruitment of vinculin is not necessarily coupled to the actin-binding conformation. However, a different measure of vinculin conformation, the recruitment of vinexin β by activated vinculin, shows that autoinhibition of endogenous vinculin is relaxed at focal adhesions. Beyond providing direct evidence that vinculin is activated at focal adhesions, this study shows that the specific functional conformation correlates with regional cellular dynamics.

scholarly journals Detection and characterization of apoptotic and necrotic cell death by time-lapse quantitative phase image analysis

2019 ◽  
Author(s):  
Tomas Vicar ◽  
Martina Raudenska ◽  
Jaromir Gumulec ◽  
Michal Masarik ◽  
Jan Balvan
Keyword(s):  
Cell Death ◽  
Cell Density ◽  
Cell Mass ◽  
Time Lapse ◽  
Intensity Change ◽  
Average Intensity ◽  
Label Free ◽  
Quantitative Phase ◽  
Label Free Detection ◽  
Direct Cell

AbstractCell viability and cytotoxicity assays are highly important for drug screening and cytotoxicity tests of antineoplastic or other therapeutic drugs. Even though biochemical-based tests are very helpful to obtain preliminary preview, their results should be confirmed by methods based on direct cell death assessment. In this study, time-dependent changes in quantitative phase-based parameters during cell death were determined and methodology useable for rapid and label-free assessment of direct cell death was introduced. Our method utilizes Quantitative Phase Imaging (QPI) which enables the time-lapse observation of subtle changes in cell mass distribution. According to our results, morphological and dynamical features extracted from QPI micrographs are suitable for cell death detection (76% accuracy in comparison with manual annotation). Furthermore, based on QPI data alone and machine learning, we were able to classify typical dynamical changes of cell morphology during both caspase 3,7-dependent and independent cell death subroutines. The main parameters used for label-free detection of these cell death modalities were cell density (pg/pixel) and average intensity change of cell pixels further designated as Cell Dynamic Score (CDS). To the best of our knowledge, this is the first study introducing CDS and cell density as a parameter typical for individual cell death subroutines with prediction accuracy 75.4 % for caspase 3,7-dependent and -independent cell death.

Temporal and Spatial Dynamics of the Actin-Based Cytoskeleton

1990 ◽  
Vol 48 (2) ◽  
pp. 546-546
Author(s):  
D. Lansing Taylor
Keyword(s):  
Spatial Dynamics ◽  
Time Lapse ◽  
Living Cells ◽  
Biomedical Sciences ◽  
3T3 Cells ◽  
Cellular Functions ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy ◽  
Temporal And Spatial ◽  
Time Lapse Imaging

There has been a renaissance and revolution in the use of light microscopy in the biomedical sciences. The renaissance has been due to the importance of studying the temporal and spatial dynamics of ions, metabolites and macromolecules in living cells and tissues. The revolution has been due to the integration of developments in molecular biology, fluorescent probe chemistry, machine vision, and imaging technology. It is now possible to use the living cell as a microcuvette and to explore the chemical and molecular dynamics responsible for cellular functions.We have been investigating the formation, transport and contraction of stress fibers in Swiss 3T3 cells. Fluorescent analogs of actin, myosin, vinculin and profilin have been investigated in serum deprived cells before, during and after stimulation with thrombin. The activities of these components of the actin-based cytoskeleton have been quantified using time-lapse imaging, fluorescence redistribution after photobleaching, video-enhanced contrast and reflection interference contrast microscopy.

scholarly journals Time-lapse imaging of microRNA activity reveals the kinetics of microRNA activation in single living cells

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Hideaki Ando ◽  
Matsumi Hirose ◽  
Gen Kurosawa ◽  
Soren Impey ◽  
Katsuhiko Mikoshiba
Keyword(s):  
Time Lapse ◽  
Living Cells ◽  
Single Living Cells ◽  
Time Lapse Imaging ◽  
Kinetics Of ◽  
Single Living
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