Cell locomotion within a contact-inhibited monolayer of chick embryonic liver parenchyma cells

1975 ◽  
Vol 18 (3) ◽  
pp. 405-425
Author(s):  
D.R. Garrod ◽  
M.S. Steinberg
Keyword(s):  
Cell Movement ◽  
Liver Parenchyma ◽  
Time Lapse ◽  
Contact Inhibition ◽  
Embryonic Liver ◽  
Relative Movement ◽  
Cell Locomotion ◽  
Epitheloid Cells ◽  
Parenchyma Cells ◽  
Better Than

Using time-lapse filming, the relative movement of cells (nuclei) within a contact-inhibited monolayer of chick embryonic liver parenchyma cells has been studied. Two techniques were employed to determine the amount of relative cell movement during a culture period of 6 h. Firstly, the number of neighbours lost or gained by each nucleus was counted. Secondly, the relative distance moved by each nucleus in relation to other nucleus in the monolayer was measured. (The numerical results obtained from these analyses and details of the methods used are given in the text). A considerable amount of relative movement of nuclei within the monolayer was found during this period of culture. Although some gaps were occasionally seen between the cells in the monolayer, it was observed that cells able both to “ruffle” and to translocate when no gap was detectable; i.e. the cells appeared able to move while entirely surrounded by other cells. Because of this, we suggest that the monolayering of these epitheloid cells on a surface may be due to restriction of overlapping between them rather than to inhibition of movement by mutual contact. We argue that the term “contact inhibition of overlapping” relates to this behaviour better than the term “contact inhibition of movement”.

Cell movements in a confluent monolayer are not caused by gaps: evidence for direct contact inhibition of overlapping

1978 ◽  
Vol 30 (1) ◽  
pp. 293-304
Author(s):  
L. Timpe ◽  
E. Martz ◽  
M.S. Steinberg
Keyword(s):  
Direct Contact ◽  
Cell Monolayer ◽  
Cell Movement ◽  
Contact Inhibition ◽  
3T3 Cells ◽  
Confluent Monolayer ◽  
Cell Movements ◽  
Cell Locomotion ◽  
Confluent Cell ◽  
A Cell

According to the hypothesis of contact inhibition of movement, cells in a confluent monolayer are restrained from major overlapping by a directional inhibition of locomotion. This explanation of monolayering proposes that contact between 2 cells locally paralyses the locomotory function, preventing movement in the direction that would lead to overlapping. Consequently, a cell in contact on all sides with neighbouring cells should be immobilized. Yet in strictly monolayered cultures of confluent chick liver or mouse 3T3 cells, we have previously observed both translational cell movements and re-shufflings of relative cell positions. The ‘confluence’ was not perfect, however, and it seemed possible that the movements observed were due to release from contact inhibition by occasional transitory gaps seen to open up between cells. In the present study, detailed gap experiences and cell movements were recorded for 31 cells over a total of 1637 cell-hours. There was no significant correlation between frequency of gaps experienced and the extent of cell movement measured as neighbour-exchanges. We conclude that gaps are not a major cause of the movements observed. The hypothesis based on contact inhibition of motion, which attempts to explain monolayering indirectly by imposing a restraint on cell locomotion, cannot explain the substantial cell movements seen in the confluent cell monolayer studied here. To explain contact inhibition of overlapping, the evidence favours a more direct hypothesis which places no restriction on cell movement other than that overlapping be avoided. Such direct avoidance of overlapping could result from differences in the strengths with which cells adhere to one another and to the substratum.

Observations on the sorting-out of embryonic cells in monolayer culture

1975 ◽  
Vol 18 (3) ◽  
pp. 385-403
Author(s):  
M.S. Steinberg ◽  
D.R. Garrod
Keyword(s):  
Monolayer Culture ◽  
Cell Movement ◽  
Time Lapse ◽  
Cell Types ◽  
Liver Cells ◽  
Contact Inhibition ◽  
Limb Bud ◽  
Embryonic Cells ◽  
Embryo Cells ◽  
Embryonic Limb

Two problems are raised concerning the movement of cells during tissue-specific sorting-out of chick embryo cells in mixed aggregates. (i) A possible expectation from the hypothesis of ‘contact inhibition’ is that cells which are entirely surrounded by other cells in monolayer should be held stationary. Cells within solid aggregates, being totally surrounded by others, might also not be expected to move. How is it then that cell movement takes place within solid aggregates during sorting-out? (ii) Are the movements of cells within sorting aggregates ‘passive’, being driven by adhesive differentials or ‘active’, being merely guided by such differentials? In order to study these questions, sorting out experiments with chick embryonic limb bud mesenchyme and liver cells were carried out in monolayer culture, permitting direct observation of cell movements. Cell behavior was observed by time-lapse cinematography. Sorting-out of these cells in monolayer began before and continued after the cells had spread to confluency. During sorting, liver cells showed ruffing activity even when they appeared to be totally surrounded by other cells. Both cell types showed contact inhibition as judged by the criterion of monolayering, for they did not move over each other but remained attached to the substratum. Yet the cells in the confluent monolayer were not immobilized. Because of this, we suggest that the observed restraint against overlapping did not result from an inhibition of movement. Several considerations, detailed in the text, suggest that cell movement during sorting-out involve active locomotion. Previous work suggest that sorting-out configurations are determined by the relative intensities of intercellular adhesive strengths, the more cohesive of 2 cell populations tending to adopt the internal position. While limb bud cells form internal islands surrounded by liver cells in solid aggregates, the reverse was found to be the case in these monolayers. This suggests that, in the monolayer, limb bud cohesiveness is depressed relative to liver cell cohesiveness. This is consistent with the observation that the limb bud cells flattened themselves markedly against the substratum, significantly decreasing their area of mutual apposition.

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 An In Vitro Model for Assessing Corneal Keratocyte Spreading and Migration on Aligned Fibrillar Collagen

2018 ◽  
Vol 9 (4) ◽  
pp. 54 ◽  
Author(s):  
Pouriska Kivanany ◽  
Kyle Grose ◽  
Nihan Yonet-Tanyeri ◽  
Sujal Manohar ◽  
Yukta Sunkara ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Cell Movement ◽  
Time Lapse ◽  
Collagen Fibrils ◽  
Fibrillar Collagen ◽  
Freeze Injury

Background: Corneal stromal cells (keratocytes) are responsible for developing and maintaining normal corneal structure and transparency, and for repairing the tissue after injury. Corneal keratocytes reside between highly aligned collagen lamellae in vivo. In addition to growth factors and other soluble biochemical factors, feedback from the extracellular matrix (ECM) itself has been shown to modulate corneal keratocyte behavior. Methods: In this study, we fabricate aligned collagen substrates using a microfluidics approach and assess their impact on corneal keratocyte morphology, cytoskeletal organization, and patterning after stimulation with platelet derived growth factor (PDGF) or transforming growth factor beta 1 (TGFβ). We also use time-lapse imaging to visualize the dynamic interactions between cells and fibrillar collagen during wound repopulation following an in vitro freeze injury. Results: Significant co-alignment between keratocytes and aligned collagen fibrils was detected, and the degree of cell/ECM co-alignment further increased in the presence of PDGF or TGFβ. Freeze injury produced an area of cell death without disrupting the collagen. High magnification, time-lapse differential interference contrast (DIC) imaging allowed cell movement and subcellular interactions with the underlying collagen fibrils to be directly visualized. Conclusions: With continued development, this experimental model could be an important tool for accessing how the integration of multiple biophysical and biochemical signals regulate corneal keratocyte differentiation.

The locomotion, shape and pseudopodial dynamics of unstimulated Dictyostelium cells are not random

1993 ◽  
Vol 106 (4) ◽  
pp. 1005-1013 ◽  
Author(s):  
T. Killich ◽  
P.J. Plath ◽  
X. Wei ◽  
H. Bultmann ◽  
L. Rensing ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Actin Polymerization ◽  
Cell Movement ◽  
Time Lapse ◽  
Phase Resetting ◽  
Wave Interference ◽  
Self Organized ◽  
Classical Wave ◽  
Spatiotemporal Oscillations ◽  
Oscillatory Waves

The dynamic periphery of unstimulated, preaggregation, hunger-stage Dictyostelium discoideum amoebae was investigated by time-lapse videomicroscopy and digital image processing. Circular maps (i.e. of each of 360 radii around the cell transformed upon Cartesian coordinates) were constructed around the centroid of individual cell images and analysed in time series. This novel technique generated spatiotemporal structures of various degrees of order in the maps, which resemble classical wave interference patterns. The patterns thus demonstrate that cell movement is not random and that cells are intrinsically vibrating bodies, transited by self-organized, superpositioned, harmonic modes of rotating oscillatory waves (ROWS). These waves appear to depend upon spatiotemporal oscillations in the physicochemical reactions associated with actin polymerization, and they govern pseudopodial movements, cell shape and locomotion generally. ROWS in this case are unrelated to the cyclic-AMP-regulated oscillations, which characterize later, aggregative populations of Dictyostelium. However, the exposure of aggregation-stage cells to a pulse of the chemoattractant cyclic-AMP induces a characteristic sequence of changes in the global cellular concentration and spatiotemporal distribution of fibrillar (F-)actin. This reaction begins with what appears to be a phase resetting of ROWS and it may, therefore, underlie the cellular perception of and response to chemotactic signals. We also develop here an analytical mathematical description of ROWS, and use it to simulate cell movements accurately.

Theory of the Non-Newtonian Rheology of Raw Rubbers Consisting of Supermolecular Rheological Units

1957 ◽  
Vol 30 (2) ◽  
pp. 460-469 ◽  
Author(s):  
M. Mooney
Keyword(s):  
Experimental Data ◽  
Flow Curve ◽  
Unit Area ◽  
Mathematical Treatment ◽  
Relative Movement ◽  
Elastic Solids ◽  
Continuous Shear ◽  
The Mean ◽  
Better Than

Abstract A theory of the viscosity of raw rubbers is developed on the postulate that raw rubbers, when subjected to continuous shear in the non-Newtonian region of flow, consist of microscopic rheological units which are semipermanent aggregates of many rubber molecules. The theory treats these units as tacky, elastic solids, whose relative movement and slippage constitute the macroscopic flow of the rubber. The resulting theoretical flow curve differs little from that given by Smallwood, but the interpretation of the parameters is radically different. The new theory leads to expressions for the number of temporary point attachments per unit area between two touching rheological units and for the mean life of these attachments. Agreement with experimental data is slightly better than in Smallwood. Two types of observed deviation from the theory can be interpreted as due to two plausible phenomena not included in the mathematical treatment.

scholarly journals MICROFILAMENTS AND CELL LOCOMOTION

1971 ◽  
Vol 49 (3) ◽  
pp. 595-613 ◽  
Author(s):  
Brian S. Spooner ◽  
Kenneth M. Yamada ◽  
Norman K. Wessells
Keyword(s):  
Protein Synthesis ◽  
Plasma Membrane ◽  
Cytochalasin B ◽  
Cell Movement ◽  
Leading Edge ◽  
Complete Recovery ◽  
Cell Locomotion ◽  
Cell Processes

The role of microfilaments in generating cell locomotion has been investigated in glial cells migrating in vitro. Such cells are found to contain two types of microfilament systems: First, a sheath of 50–70-A in diameter filaments is present in the cytoplasm at the base of the cells, just inside the plasma membrane, and in cell processes. Second, a network of 50-A in diameter filaments is found just beneath the plasma membrane at the leading edge (undulating membrane locomotory organelle) and along the sides of the cell. The drug, cytochalasin B, causes a rapid cessation of migration and a disruption of the microfilament network. Other organelles, including the microfilament sheath and microtubules, are unaltered by the drug, and protein synthesis is not inhibited. Removal of cytochalasin results in complete recovery of migratory capabilities, even in the absence of virtually all protein synthesis. Colchicine, at levels sufficient to disrupt all microtubules, has no effect on undulating membrane activity, on net cell movement, or on microfilament integrity. The microfilament network is, therefore, indispensable for locomotion.

scholarly journals Are cross-bridging structures involved in the bundle formation of intermediate filaments and the decrease in locomotion that accompany cell aging?

1985 ◽  
Vol 100 (5) ◽  
pp. 1466-1473 ◽  
Author(s):  
E Wang
Keyword(s):  
Intermediate Filaments ◽  
Electron Microscopic Examination ◽  
Time Lapse ◽  
Cell Aging ◽  
Electron Microscopic ◽  
Cell Locomotion ◽  
Wide Range ◽  
Filament Bundles ◽  
Large Filament

Five different fibroblast strains derived from donors of a wide range of ages were used for investigation of senescence-associated changes in the organization of intermediate filaments (IFs) and the activity of cell locomotion. Results of immunofluorescence microscopy demonstrate that, in large and flat in vitro aged fibroblasts, vimentin-containing IFs are distributed as unusually organized large bundles. Electron microscopic examination shows that these large bundles are indeed composed of filaments of 8-10 nm. Such a profile of large bundles is rarely seen in young fibroblasts whose IFs are usually interdispersed among microtubules. Within the large filament bundles of senescent fibroblasts, cross-bridge-like extensions are frequently observed along the individual IFs. Immunogold labeling with antibody to one of the cross-bridging proteins, p50, further illustrates the abundance of interfilament links within the IF bundles. The senescence-related increase in interfilament association was also supported by the results of co-precipitation between vimentin and an associated protein of 50,000 D. Time-lapse cinematographic studies of cell locomotion reveal that accompanying aging, fibroblasts have a significantly reduced ability to translocate across a solid substratum. These results led me to suggest that the increased interfilament links via cross-bridges may in part contribute to the mechanism that orchestrates the formation of large filament bundles. The presence of enormous bundles in the cytoplasm may physically impede the efficiency of locomotion for these nondividing cells.

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