An abnormality of cell behaviour in human dystrophic muscle cultures: a time-lapse study

1979 ◽  
Vol 38 (1) ◽  
pp. 201-210
Author(s):  
R. Yasin ◽  
G. Van Beers ◽  
P.N. Riddle ◽  
D. Brown ◽  
G. Widdowson ◽  
...  
Keyword(s):  
Growth And Development ◽  
Single Cells ◽  
Time Lapse ◽  
Development Pattern ◽  
Dystrophic Muscle ◽  
Cell Behaviour ◽  
Cluster Development ◽  
Myotube Formation ◽  
Muscle Cultures ◽  
Insight Into

The initiation of monolayer mass cell cultures from adult human biopsies has revealed a striking abnormality in the growth and development pattern of muscle cultures from Duchenne-type dystrophy. This abnormality in cell behaviour was seen as early as 4 days in culture, well before myotube formation or confluence, and consisted of areas where cells clustered together in a multilayered mass rather than showing the typical monolayer distribution normally observed. To gain some insight into the mechanism of cell cluster development, we have examined such a culture by time-lapse cinematography and also the cell behaviour of other control cultures. The results of this study show that the clusters enlarged primarily by cell division and, to a lesser extent, by the acquisition of neighbouring cells. Furthermore, none of the single cells surrounding the clusters exhibited contact inhibition of movement. This behaviour was not observed in the other cultures examined. These findings could be indicative of an abnormality in the cell surface or cell-locomotory machinery of dystrophic cells.

Cell behaviour in a polygonal cell sheet*

Development ◽  
1984 ◽  
Vol 83 (Supplement) ◽  
pp. 313-327
Author(s):  
H. Honda ◽  
R. Kodama ◽  
T. Takeuchi ◽  
H. Yamanaka ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Cell Sheet ◽  
Cell Monolayer ◽  
Time Lapse ◽  
Geometrical Method ◽  
Cell Behaviour ◽  
Cell Monolayers ◽  
Polygonal Cell ◽  
Computer Based ◽  
Insight Into

Cell monolayers on culture dishes were divided into two groups: tensile monolayers and non-tensile ones. In the development of an epithelium, a non-tensile cell monolayer turns into a tightly bound tensile one. Detection of these states was carried out by using the boundary shortening procedure, a computer-based geometrical method to show how much the polygonal cell boundary contracts. Non-tensile monolayers were divided further into two groups according to their motility: a fluctuating monolayer in which cells move laterally, and a stable monolayer in which cells are immobilized. Quantitative determination of cell motility was performed by analysing time-lapse cellular patterns. These computer-based geometrical analyses enabled us to divide monolayers into three groups: tensile stable monolayers, non-tensile stable monolayers and fluctuating monolayers, and this study therefore gives an insight into the way in which changing conformations of cells may be assayed.

scholarly journals Stochasticity in Colonial Growth Dynamics of Individual Bacterial Cells

2013 ◽  
Vol 79 (7) ◽  
pp. 2294-2301 ◽  
Author(s):  
Konstantinos P. Koutsoumanis ◽  
Alexandra Lianou
Keyword(s):  
Kinetic Parameters ◽  
Single Cells ◽  
Growth Curves ◽  
Growth Dynamics ◽  
Time Lapse ◽  
Initial Population ◽  
Bacterial Cells ◽  
Stochastic Growth ◽  
Bacterial Populations ◽  
Content Type

ABSTRACTConventional bacterial growth studies rely on large bacterial populations without considering the individual cells. Individual cells, however, can exhibit marked behavioral heterogeneity. Here, we present experimental observations on the colonial growth of 220 individual cells ofSalmonella entericaserotype Typhimurium using time-lapse microscopy videos. We found a highly heterogeneous behavior. Some cells did not grow, showing filamentation or lysis before division. Cells that were able to grow and form microcolonies showed highly diverse growth dynamics. The quality of the videos allowed for counting the cells over time and estimating the kinetic parameters lag time (λ) and maximum specific growth rate (μmax) for each microcolony originating from a single cell. To interpret the observations, the variability of the kinetic parameters was characterized using appropriate probability distributions and introduced to a stochastic model that allows for taking into account heterogeneity using Monte Carlo simulation. The model provides stochastic growth curves demonstrating that growth of single cells or small microbial populations is a pool of events each one of which has its own probability to occur. Simulations of the model illustrated how the apparent variability in population growth gradually decreases with increasing initial population size (N0). For bacterial populations withN0of >100 cells, the variability is almost eliminated and the system seems to behave deterministically, even though the underlying law is stochastic. We also used the model to demonstrate the effect of the presence and extent of a nongrowing population fraction on the stochastic growth of bacterial populations.

scholarly journals Measuring fast gene dynamics in single cells with time-lapse luminescence microscopy

2014 ◽  
Vol 25 (22) ◽  
pp. 3699-3708 ◽  
Author(s):  
Anyimilehidi Mazo-Vargas ◽  
Heungwon Park ◽  
Mert Aydin ◽  
Nicolas E. Buchler
Keyword(s):  
Gene Expression ◽  
Fluorescent Proteins ◽  
Single Cells ◽  
Time Lapse ◽  
Photon Flux ◽  
Luminescence Microscopy ◽  
Cell Cycle Genes ◽  
Light Excitation ◽  
Better Than

Time-lapse fluorescence microscopy is an important tool for measuring in vivo gene dynamics in single cells. However, fluorescent proteins are limited by slow chromophore maturation times and the cellular autofluorescence or phototoxicity that arises from light excitation. An alternative is luciferase, an enzyme that emits photons and is active upon folding. The photon flux per luciferase is significantly lower than that for fluorescent proteins. Thus time-lapse luminescence microscopy has been successfully used to track gene dynamics only in larger organisms and for slower processes, for which more total photons can be collected in one exposure. Here we tested green, yellow, and red beetle luciferases and optimized substrate conditions for in vivo luminescence. By combining time-lapse luminescence microscopy with a microfluidic device, we tracked the dynamics of cell cycle genes in single yeast with subminute exposure times over many generations. Our method was faster and in cells with much smaller volumes than previous work. Fluorescence of an optimized reporter (Venus) lagged luminescence by 15–20 min, which is consistent with its known rate of chromophore maturation in yeast. Our work demonstrates that luciferases are better than fluorescent proteins at faithfully tracking the underlying gene expression.

scholarly journals HARBOR STUDY FOR SAN NICOLAS BAY, PERU

1970 ◽  
Vol 1 (12) ◽  
pp. 133
Author(s):  
James M. Keith ◽  
Emmett J. Murphy
Keyword(s):  
Particle Velocity ◽  
Time Lapse ◽  
Wave Action ◽  
Ship Motion ◽  
Long Period ◽  
Wave Property ◽  
Directional Wave ◽  
Detailed Interpretation ◽  
Wave Phenomena ◽  
Insight Into

A pair of ducted impeller current meters, one mounted vertically and the other horizontally, were used to measure wave action at San Nicolas Harbor, Peru The horizontal water velocity records are superior to conventional wave records because they measure directly the wave property which induces adverse horizontal ship motion, and provide directional wave data Spectral analysis methods proved well-suited to detailed interpretation of the particle velocity records, while considerable insight into the wave phenomena was gained by simple, rational inspections and interpretations of the records Time-lapse movies of a moored ship, when correlated with simultaneous water particle velocity records, provided an exceptionally clear picture of ship response to wave action, and led to the rather surprising observation that long-period ship motion is not necessarily caused by long-period waves The foregoing ship response was duplicated in hydrau1ic model tests.

scholarly journals A family of T6SS antibacterial effectors related to L,D-transpeptidases targets the Peptidoglycan

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Stephanie Sibinelli de Sousa ◽  
Julia Takuno Hespanhol ◽  
Bruno Matsuyama ◽  
Stephane Mesnage ◽  
Gianlucca Nicastro ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Point Mutations ◽  
Time Lapse ◽  
Secretion Systems ◽  
Bacterial Antagonism ◽  
New Family ◽  
Type Vi Secretion ◽  
Altered Cell ◽  
Bacterial Effectors ◽  
Insight Into

Type VI secretion systems (T6SSs) are contractile nanomachines widely used by bacteria to intoxicate competitors. Salmonella Typhimurium encodes a T6SS within the Salmonella pathogenicity island 6 (SPI-6) that is used during competition against species of the gut microbiota. We characterized a new SPI-6 T6SS antibacterial effector named Tlde1 (type VI L,D-transpeptidase effector 1). Tlde1 is toxic in target-cell periplasm and its toxicity is neutralized by co-expression with immunity protein Tldi1 (type VI L,D-transpeptidase immunity 1). Time-lapse microscopy revealed that intoxicated cells display altered cell division and lose cell envelope integrity. Bioinformatics analysis showed that Tlde1 is evolutionarily related to L,D-transpeptidases. Point mutations on conserved histidine121 and cysteine131 residues eliminated toxicity. Co-incubation of purified recombinant Tlde1 and peptidoglycan tetrapeptides showed that Tlde1 displays both L,D-carboxypeptidase activity by cleaving GM-tetrapeptides between meso-diaminopimelic acid3 and D-alanine4, and L,D-transpeptidase exchange activity by replacing D-alanine4 for a non-canonical D-amino acid. Tlde1 constitutes a new family of T6SS effectors widespread in Proteobacteria. This work increases our knowledge about the bacterial effectors used in interbacterial competitions and provides molecular insight into a new mechanism of bacterial antagonism.

Learning for Another: From Self-Interest to Altruism

2015 ◽  
Vol 57 (3) ◽  
pp. 252-280 ◽  
Author(s):  
Aaron W. Snyder ◽  
Stephen C. Yanchar ◽  
Edwin E. Gantt
Keyword(s):  
Qualitative Study ◽  
Growth And Development ◽  
Learning Experiences ◽  
Case Analysis ◽  
Communal Learning ◽  
Self Interest ◽  
Cross Case Analysis ◽  
Insight Into

This qualitative study offers an examination of the learning experiences of six individuals, each of whom initially learned for self-interested purposes, but later experienced a shift in their desire and pursued learning to benefit others. We conducted interviews that described this phenomenon and provided insight into the following question: What is the experience of a learner who transitions from learning out of self-interest to learning for the sake of another? Findings of this study include narrative case summaries for each participant and a cross-case analysis that includes six major themes regarding participants’ transition to altruistic forms of learning: humility as a prerequisite, communal learning, emphasis on the success of others, becoming more self-confident, becoming a more effective learner, and becoming more other centered. Overall, participants in this study found the most meaning by helping recipients achieve their own growth and development rather than by merely accomplishing tasks.

scholarly journals Quantifying exosome secretion from single cells reveals a modulatory role for GPCR signaling

2018 ◽  
Vol 217 (3) ◽  
pp. 1129-1142 ◽  
Author(s):  
Frederik Johannes Verweij ◽  
Maarten P. Bebelman ◽  
Connie R. Jimenez ◽  
Juan J. Garcia-Vallejo ◽  
Hans Janssen ◽  
...  
Keyword(s):  
Total Internal Reflection ◽  
Single Cells ◽  
Cell Communication ◽  
Exosome Biogenesis ◽  
Real Time Visualization ◽  
Target Membrane ◽  
Syntaxin 4 ◽  
Optical Reporters ◽  
Druggable Targets ◽  
Insight Into

Exosomes are small endosome-derived extracellular vesicles implicated in cell–cell communication and are secreted by living cells when multivesicular bodies (MVBs) fuse with the plasma membrane (PM). Current techniques to study exosome physiology are based on isolation procedures after secretion, precluding direct and dynamic insight into the mechanics of exosome biogenesis and the regulation of their release. In this study, we propose real-time visualization of MVB–PM fusion to overcome these limitations. We designed tetraspanin-based pH-sensitive optical reporters that detect MVB–PM fusion using live total internal reflection fluorescence and dynamic correlative light–electron microscopy. Quantitative analysis demonstrates that MVB–PM fusion frequency is reduced by depleting the target membrane SNAREs SNAP23 and syntaxin-4 but also can be induced in single cells by stimulation of the histamine H1 receptor (H1HR). Interestingly, activation of H1R1 in HeLa cells increases Ser110 phosphorylation of SNAP23, promoting MVB–PM fusion and the release of CD63-enriched exosomes. Using this single-cell resolution approach, we highlight the modulatory dynamics of MVB exocytosis that will help to increase our understanding of exosome physiology and identify druggable targets in exosome-associated pathologies.

Growth in cell length in the fission yeast Schizosaccharomyces pombe

1985 ◽  
Vol 75 (1) ◽  
pp. 357-376 ◽  
Author(s):  
J.M. Mitchison ◽  
P. Nurse
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Cell Size ◽  
Single Cells ◽  
Temperature Shift ◽  
Time Lapse ◽  
Cell Length ◽  
Wild Type ◽  
Cycle Growth ◽  
A Cell ◽  
Mutant Cells

The cylindrical cells of Schizosaccharomyces pombe grow in length by extension at the ends and not the middle. At the beginning of the cell cycle, growth is restricted to the ‘old end’, which existed in the previous cycle. Later on, the ‘new end’, formed from the septum, starts to grow at a point in the cycle that we have called NETO (‘new end take-off’). Fluorescence microscopy on cells stained with Calcofluor has been used to study NETO in size mutants, in blocked cdc mutants and with different growth temperatures and media. In wild-type cells (strain 972) NETO happens at 0.34 of the cycle with a cell length of 9.5 microns. With size mutants that are smaller at division, NETO takes place at the same size (9.0-9.5 microns) but this is not achieved until later in the cycle. Another control operates in larger size mutants since NETO occurs at the same stage of the cycle (about 0.32) as in wild type but at a larger cell size. This control is probably a requirement to have completed an event in early G2, since most cdc mutant cells blocked before this point in the cycle do not show NETO whereas most of those blocked in late G2 do show it. We conclude that NETO only happens if: (1) the cell length is greater than a critical value of 9.0-9.5 microns; and (2) the cell has traversed the first 0.3-0.35 of the cycle and passed early G2. NETO is delayed in poor media, in which cell size is also reduced. Temperature has little effect on NETO under steady-state conditions, but there is a transient delay for some hours after a temperature shift. NETO is later in another wild-type strain, 132. Time-lapse photomicrography was used to follow the rates of length growth in single cells. Wild-type cells showed two linear segments during the first 75% of the cycle. There was a rate-change point (RCP), coincident with NETO, where the rate of total length extension increased by 35%. This increase was not due simply to the start of new-end growth, since old-end growth slowed down in some cells at the RCP. cdc 11.123 is a mutant in which septation and division is blocked at 35 degrees C but nuclear division continues.(ABSTRACT TRUNCATED AT 400 WORDS)

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