scholarly journals Hyperosmotic Stress Response Memory is Modulated by Gene Positioning in Yeast

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 582 ◽  
Author(s):  
Zacchari Ben Meriem ◽  
Yasmine Khalil ◽  
Pascal Hersen ◽  
Emmanuelle Fabre
Keyword(s):  
Single Cell ◽  
Quantitative Description ◽  
Time Lapse ◽  
Chromatin Domain ◽  
Unicellular Eukaryote ◽  
Cellular Memory ◽  
Fluorescent Reporter ◽  
Activation Patterns ◽  
Stress Memory ◽  
Gene Positioning

Cellular memory is a critical ability that allows microorganisms to adapt to potentially detrimental environmental fluctuations. In the unicellular eukaryote Saccharomyces cerevisiae, cellular memory can take the form of faster or slower responses within the cell population to repeated stresses. Using microfluidics and fluorescence time-lapse microscopy, we studied how yeast responds to short, pulsed hyperosmotic stresses at the single-cell level by analyzing the dynamic behavior of the stress-responsive STL1 promoter (pSTL1) fused to a fluorescent reporter. We established that pSTL1 exhibits variable successive activation patterns following two repeated short stresses. Despite this variability, most cells exhibited a memory of the first stress as decreased pSTL1 activity in response to the second stress. Notably, we showed that genomic location is important for the memory effect, since displacement of the promoter to a pericentromeric chromatin domain decreased the transcriptional strength of pSTL1 and led to a loss of memory. This study provides a quantitative description of a cellular memory that includes single-cell variability and highlights the contribution of chromatin structure to stress memory.

scholarly journals The memory of hyperosmotic stress response in yeast is modulated by gene-positioning

2019 ◽  
Author(s):  
Zacchari Ben Meriem ◽  
Yasmine Khalil ◽  
Pascal Hersen ◽  
Emmanuelle Fabre
Keyword(s):  
Single Cell ◽  
Dynamical Behavior ◽  
Quantitative Description ◽  
Time Lapse ◽  
Chromatin Domain ◽  
Unicellular Eukaryote ◽  
Cellular Memory ◽  
Fluorescent Reporter ◽  
Stress Memory ◽  
Gene Positioning

AbstractCellular memory is a critical ability displayed by microorganisms in order to adapt to potentially detrimental environmental fluctuations. In the unicellular eukaryoteS. cerevisiaecellular memory can take the form of a faster or a decreased response following repeated stresses in cell population. Using microfluidics and fluorescence time-lapse microscopy, we studied how yeasts respond to short-pulsed hyperosmotic stresses at the single-cell level by analyzing the dynamical behavior of the stress responsive STL1 promoter fused to a fluorescent reporter. We established that pSTL1 shows variability in its successive activations following two repeated short stresses. Despite this variability, most cells displayed a memory of past stresses through a decreased activity of pSTL1 upon repeated stress. Notably, we showed that genomic location is important for the memory effect since promoter displacement to a pericentromeric chromatin domain leads to a decreased transcriptional strength of pSTL1 and to the loss of memory. This study provides a quantitative description of a cellular memory that includes single-cell variability and points towards the contribution of the chromatin structure in stress memory.

scholarly journals Development of single-cell-level microfluidic technology for long-term growth visualization of living cultures of Mycobacterium smegmatis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Han Wang ◽  
Gloria M. Conover ◽  
Song-I Han ◽  
James C. Sacchettini ◽  
Arum Han
Keyword(s):  
Drug Treatment ◽  
Single Cell ◽  
Mycobacterium Smegmatis ◽  
Culture Media ◽  
Low Cost ◽  
Bacterial Pathogen ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Cell Phenotype

AbstractAnalysis of growth and death kinetics at single-cell resolution is a key step in understanding the complexity of the nonreplicating growth phenotype of the bacterial pathogen Mycobacterium tuberculosis. Here, we developed a single-cell-resolution microfluidic mycobacterial culture device that allows time-lapse microscopy-based long-term phenotypic visualization of the live replication dynamics of mycobacteria. This technology was successfully applied to monitor the real-time growth dynamics of the fast-growing model strain Mycobacterium smegmatis (M. smegmatis) while subjected to drug treatment regimens during continuous culture for 48 h inside the microfluidic device. A clear morphological change leading to significant swelling at the poles of the bacterial membrane was observed during drug treatment. In addition, a small subpopulation of cells surviving treatment by frontline antibiotics was observed to recover and achieve robust replicative growth once regular culture media was provided, suggesting the possibility of identifying and isolating nonreplicative mycobacteria. This device is a simple, easy-to-use, and low-cost solution for studying the single-cell phenotype and growth dynamics of mycobacteria, especially during drug treatment.

scholarly journals Deciphering the Receptor Repertoire Encoding Specific Odorants by Time-Lapse Single-Cell Array Cytometry

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Masato Suzuki ◽  
Nobuo Yoshimoto ◽  
Ken Shimono ◽  
Shun’ichi Kuroda
Keyword(s):  
Single Cell ◽  
Time Lapse ◽  
Cell Array ◽  
Receptor Repertoire

scholarly journals Live-cell time-lapse imaging and single-cell tracking of in vitro cultured neural stem cells – Tools for analyzing dynamics of cell cycle, migration, and lineage selection

Methods ◽  
2018 ◽  
Vol 133 ◽  
pp. 81-90 ◽  
Author(s):  
Katja M. Piltti ◽  
Brian J. Cummings ◽  
Krystal Carta ◽  
Ayla Manughian-Peter ◽  
Colleen L. Worne ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Neural Stem Cells ◽  
Single Cell ◽  
Cell Tracking ◽  
Time Lapse ◽  
Live Cell ◽  
Time Lapse Imaging

scholarly journals Cell-to-cell heterogeneity in Escherichia coli stress response originates from pulsatile expression and growth

2020 ◽  
Author(s):  
Nadia M. V. Sampaio ◽  
Caroline M. Blassick ◽  
Jean-Baptiste Lugagne ◽  
Mary J. Dunlop
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Response ◽  
Single Cell ◽  
Phenotypic Variability ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Cell Heterogeneity ◽  
Temporal Expression ◽  
Functional Consequences

AbstractCell-to-cell heterogeneity in gene expression and growth can have critical functional consequences, such as determining whether individual bacteria survive or die following stress. Although phenotypic variability is well documented, the dynamics that underlie it are often unknown. This information is critical because dramatically different outcomes can arise from gradual versus rapid changes in expression and growth. Using single-cell time-lapse microscopy, we measured the temporal expression of a suite of stress response reporters in Escherichia coli, while simultaneously monitoring growth rate. In conditions without stress, we found widespread examples of pulsatile expression. Single-cell growth rates were often anti-correlated with gene expression, with changes in growth preceding changes in expression. These pulsatile dynamics have functional consequences, which we demonstrate by measuring survival after challenging cells with the antibiotic ciprofloxacin. Our results suggest that pulsatile expression and growth dynamics are common in stress response networks and can have direct consequences for survival.

scholarly journals Live imaging of apoptosis in a novel transgenic mouse highlights its role in neural tube closure

2011 ◽  
Vol 195 (6) ◽  
pp. 1047-1060 ◽  
Author(s):  
Yoshifumi Yamaguchi ◽  
Naomi Shinotsuka ◽  
Keiko Nonomura ◽  
Kiwamu Takemoto ◽  
Keisuke Kuida ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Neural Tube ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Lapse ◽  
Neural Tube Closure ◽  
Caspase Activation ◽  
Fluorescent Reporter ◽  
Time Lapse Imaging ◽  
Tube Closure

Many cells die during development, tissue homeostasis, and disease. Dysregulation of apoptosis leads to cranial neural tube closure (NTC) defects like exencephaly, although the mechanism is unclear. Observing cells undergoing apoptosis in a living context could help elucidate their origin, behavior, and influence on surrounding tissues, but few tools are available for this purpose, especially in mammals. In this paper, we used insulator sequences to generate a transgenic mouse that stably expressed a genetically encoded fluorescence resonance energy transfer (FRET)–based fluorescent reporter for caspase activation and performed simultaneous time-lapse imaging of apoptosis and morphogenesis in living embryos. Live FRET imaging with a fast-scanning confocal microscope revealed that cells containing activated caspases showed typical and nontypical apoptotic behavior in a region-specific manner during NTC. Inhibiting caspase activation perturbed and delayed the smooth progression of cranial NTC, which might increase the risk of exencephaly. Our results suggest that caspase-mediated cell removal facilitates NTC completion within a limited developmental window.

scholarly journals More than efficacy revealed by single-cell analysis of antiviral therapeutics

2019 ◽  
Vol 5 (10) ◽  
pp. eaax4761 ◽  
Author(s):  
Wu Liu ◽  
Mehmet U. Caglar ◽  
Zhangming Mao ◽  
Andrew Woodman ◽  
Jamie J. Arnold ◽  
...  
Keyword(s):  
Viral Infection ◽  
Single Cell ◽  
Single Cell Analysis ◽  
Principal Component ◽  
Cell Analysis ◽  
Infection Cycle ◽  
Reporter Protein ◽  
Fluorescent Reporter ◽  
Infection Dynamics ◽  
Infected Cells

Because many aspects of viral infection dynamics and inhibition are governed by stochastic processes, single-cell analysis should provide more information than approaches using population averaging. We have developed a microfluidic device composed of ~6000 wells, with each well containing a microstructure to capture single, infected cells replicating an enterovirus expressing a fluorescent reporter protein. We have used this system to characterize enterovirus inhibitors with distinct mechanisms of action. Single-cell analysis reveals that each class of inhibitor interferes with the viral infection cycle in a manner that can be distinguished by principal component analysis. Single-cell analysis of antiviral candidates not only reveals efficacy but also facilitates clustering of drugs with the same mechanism of action and provides some indication of the ease with which resistance will develop.

scholarly journals Label free, quantitative single-cell fate tracking of time-lapse movies

MethodsX ◽  
2019 ◽  
Vol 6 ◽  
pp. 2468-2475 ◽  
Author(s):  
C. Elizabeth Caldon ◽  
Andrew Burgess
Keyword(s):  
Single Cell ◽  
Cell Fate ◽  
Time Lapse ◽  
Label Free ◽  
Cell Fate Tracking

scholarly journals Dissecting miRNA gene repression on single cell level with an advanced fluorescent reporter system

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Nicolas Lemus-Diaz ◽  
Kai O. Böker ◽  
Ignacio Rodriguez-Polo ◽  
Michael Mitter ◽  
Jasmin Preis ◽  
...  
Keyword(s):  
Single Cell ◽  
Mirna Gene ◽  
Gene Repression ◽  
Single Cell Level ◽  
Reporter System ◽  
Cell Level ◽  
Fluorescent Reporter
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