scholarly journals Universal kinetics for engagement of mechanosensing pathways in cell adhesion

2018 ◽  
Author(s):  
Eugene Terentjev ◽  
Samuel Bell ◽  
Anna-Lena Redmann
Keyword(s):  
Population Dynamics ◽  
Cell Morphology ◽  
Focal Adhesions ◽  
Early Time ◽  
Cell Spreading ◽  
Stem Cell Differentiation ◽  
Activation Temperature ◽  
Long Time ◽  
The Individual ◽  
Kinetics Of

AbstractWhen plated onto substrates, cell morphology and even stem cell differentiation are influenced by the stiffness of their environment. Stiffer substrates give strongly spread (eventually polarized) cells with strong focal adhesions, and stress fibers; very soft substrates give a less developed cytoskeleton, and much lower cell spreading. The kinetics of this process of cell spreading is studied extensively, and important universal relationships are established on how the cell area grows with time. Here we study the population dynamics of spreading cells, investigating the characteristic processes involved in cell response to the substrate. We show that unlike the individual cell morphology, this population dynamics does not depend on the substrate stiffness. Instead, a strong activation temperature dependence is observed. Different cell lines on different substrates all have long-time statistics controlled by the thermal activation over a single energy barrier ∆G ≈ 19 kcal/mol, while the early-time kinetics follows a power law ~ t5. This implies that the rate of spreading depends on an internal process of adhesion-mechanosensing complex assembly and activation: the operational complex must have 5 component proteins, and the last process in the sequence (which we believe is the activation of focal adhesion kinase) is controlled by the binding energy ∆G.

Micro-Engineered Sythetical Extrocellular Metrix for Stem Cell Differentiation Study

2010 ◽  
Author(s):  
Jianping Fu
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Cell Morphology ◽  
Focal Adhesions ◽  
Stem Cell Differentiation ◽  
Material Surface ◽  
Single Cell Level ◽  
Cell Level ◽  
Substrate Rigidity ◽  
Non Destructive

We report the use of micromolded elastomeric micropost arrays to modulate substrate rigidity independently of effects on adhesive and other material surface properties. We demonstrate that micropost rigidity impacts cell morphology, focal adhesions, cytoskeletal contractility, and stem cell differentiation. Furthermore, these micropost arrays reveal that changes in cytoskeletal contractility can precede stem cell differentiation and be utilized as a non-destructive predictor for fate decisions at the single cell level.

scholarly journals Development of nascent focal adhesions in spreading cells

2020 ◽  
Author(s):  
Neil Ibata ◽  
Eugene M. Terentjev
Keyword(s):  
Focal Adhesions ◽  
Cell Spreading ◽  
Angular Frequency ◽  
Ginzburg Landau ◽  
Spatial Modes ◽  
Characteristic Wavelength ◽  
Physical Interactions ◽  
The Individual ◽  
Computer Simulation Studies ◽  
Dense Aggregation

AbstractCell spreading provides one of the simplest configurations in which eukaryotic cells develop angular symmetry-breaking assemblies of mechanosensing and mechanotransducive organelles in preparation for cell differentiation and movement. By identifying the edge of the cell-ECM adhesion area as having an important role in mechanosensor complex aggregation, we consider the spatial patterns arising on this edge, within a 1D lattice model of the nearest-neighbour interaction between individual integrin-mediated mechanosensors. We obtain the Ginzburg-Landau free energy for this model and analyse the spectrum of spatial modes as the cell spreads and increases the contact area. We test the plausibility of our model by comparing its predictions for the azimuthal angular frequency of aggregation of mechanosensors into nascent focal adhesions (FAs) to observations of the paxillin distribution in spreading fibroblasts.STATEMENT OF SIGNIFICANCEThe topic of cell adhesion on substrates is very active, with numerous theoretical, experimental and computer simulation studies probing the mechanisms and signalling pathways of cell response to interacting with substrate. Integrin-based adhesion complexes are known to be the individual units of this process, and their dense aggregation into focal adhesions leads to cells developing asymmetry, polarity, and eventually - locomotion. Here we develop a theoretical model that suggests that physical interactions between individual adhesion complexes is the factor that defines the initial breaking of symmetry of the cell spreading on substrate, and predicts the characteristic wavelength of modulation above the critical size of adhesion area.

Mechanical Regulation of Stem Cell Differentiation on Geometrically Modulated Elastomeric Substrates

2010 ◽  
Author(s):  
Jianping Fu
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Cell Morphology ◽  
Focal Adhesions ◽  
Stem Cell Differentiation ◽  
Material Surface ◽  
Single Cell Level ◽  
Cell Level ◽  
Substrate Rigidity ◽  
Non Destructive

We report the use of micromolded elastomeric micropost arrays to modulate substrate rigidity independently of effects on adhesive and other material surface properties. We demonstrate that micropost rigidity impacts cell morphology, focal adhesions, cytoskeletal contractility, and stem cell differentiation. Furthermore, these micropost arrays reveal that changes in cytoskeletal contractility can precede stem cell differentiation and be utilized as a non-destructive predictor for fate decisions at the single cell level.

ADHD with Comorbid Bipolar Disorders: A Systematic Review of Neurobiological, Clinical and Pharmacological Aspects Across the Lifespan

2019 ◽  
Vol 26 (38) ◽  
pp. 6942-6969 ◽  
Author(s):  
Federico Mucci ◽  
Maria Teresa Avella ◽  
Donatella Marazziti
Keyword(s):  
Clinical Features ◽  
Adult Adhd ◽  
Neurodevelopmental Disorder ◽  
Bipolar Disorders ◽  
Mood Stabilizers ◽  
Disruptive Behaviour ◽  
Single Individual ◽  
Pharmacological Management ◽  
Long Time ◽  
The Individual

Background: Attention deficit hyperactivity (ADHD) disorder is a neurodevelopmental disorder characterized by inattention, hyperactivity, disruptive behaviour, and impulsivity. Despite considered typical of children for a long time, the persistence of ADHD symptoms in adulthood gained increasing interest during the last decades. Indeed, its diagnosis, albeit controversial, is rarely carried out even because ADHD is often comorbid with several other psychiatric diosrders, in particular with bipolar disorders (BDs), a condition that complicates the clinical picture, assessment and treatment. Aims: The aim of this paper was to systematically review the scientific literature on the neurobiological, clinical features and current pharmacological management of ADHD comorbid with BDs across the entire lifespan, with a major focus on the adulthood. Discussion: The pharmacology of ADHD-BD in adults is still empirical and influenced by the individual experience of the clinicians. Stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants are useful when a substance abuse history is detected, although they require some weeks in order to be fully effective. In any case, an in-depth diagnostic and clinical evaluation of the single individual is mandatory. Conclusions: The comorbidity of ADHD with BD is still a controversial matter, as it is the notion of adult ADHD as a distinct nosological category. Indeed, some findings highlighted the presence of common neurobiological mechanisms and overlapping clinical features, although disagreement does exist. In any case, while expecting to disentangle this crucial question, a correct management of this comorbidity is essential, which requires the co-administration of mood stabilizers. Further controlled clinical studies in large samples of adult ADHD-BD patients appear extremely urgent in order to better define possible therapeutic guidelines, as well as alternative approaches for this potentially invalidating condition.

Kinetics and Mechanism of Decomposition of 1,3-Bis(4-methylphenyl)triazene Catalyzed with Substituted Benzoic Acids in 25% Aqueous Methanol-General or Specific Catalysis?

1994 ◽  
Vol 59 (9) ◽  
pp. 2029-2041
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná
Keyword(s):  
Benzoic Acids ◽  
Hammett Equation ◽  
Aqueous Methanol ◽  
Mechanism Of Decomposition ◽  
Kinetics Of Decomposition ◽  
Independent Variable ◽  
Amino Derivatives ◽  
Substituted Benzoic Acids ◽  
The Individual ◽  
Kinetics Of

The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effect is described by the Hammett equation. The statistically best model in which the observed rate constant is a superposition of a term describing the dependence on proton concentration and a term describing the dependence on the product of concentrations of proton and conjugated base is valid with the presumption of complete proton transfer from the catalyst acid to substrate, which has been proved. The behaviour of 4-dimethylamino, 4-amino, and 3-amino derivatives is anomalous (lower catalytic activity as compared with benzoic acid). This supports the presumed participation of conjugated base in the title process.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

scholarly journals Exploring early time points of vimentin assembly in flow by fluorescence fluctuation spectroscopy

Lab on a Chip ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 735-745
Author(s):  
Eleonora Perego ◽  
Sarah Köster
Keyword(s):  
Reaction Kinetics ◽  
Photon Counting ◽  
Early Time ◽  
Fluorescence Fluctuation Spectroscopy ◽  
Microfluidic Mixing ◽  
Time Points ◽  
Photon Counting Histogram ◽  
Kinetics Of

The combination of photon counting histogram and microfluidic mixing reveals early time points in reaction kinetics of biomolecule aggregation.

scholarly journals Multifaceted phase ordering kinetics of an antiferromagnetic spin-1 condensate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Pietraszewicz ◽  
Aleksandra Seweryn ◽  
Emilia Witkowska
Keyword(s):  
Scaling Laws ◽  
Study Phase ◽  
One Dimensional ◽  
Phase Domain ◽  
Ordering Kinetics ◽  
Domain Coarsening ◽  
Long Time ◽  
Phase Ordering ◽  
Kinetics Of ◽  
Antiferromagnetic Spin

AbstractWe study phase domain coarsening in the long time limit after a quench of magnetic field in a quasi one-dimensional spin-1 antiferromagnetic condensate. We observe that the growth of correlation length obeys scaling laws predicted by the two different models of phase ordering kinetics, namely the binary mixture and vector field. We derive regimes of clear realization for both of them. We demonstrate appearance of atypical scaling laws, which emerge in intermediate regions.

Myocilin binding to Hep II domain of fibronectin inhibits cell spreading and incorporation of paxillin into focal adhesions

2005 ◽  
Vol 303 (2) ◽  
pp. 218-228 ◽  
Author(s):  
Donna M. Peters ◽  
Kathleen Herbert ◽  
Brenda Biddick ◽  
Jennifer A. Peterson
Keyword(s):  
Focal Adhesions ◽  
Cell Spreading

The Influence of Environmental Factors on Daily Behaviour

1982 ◽  
Vol 14 (9) ◽  
pp. 1175-1193 ◽  
Author(s):  
R Herz
Keyword(s):  
Social Sciences ◽  
Physical Environment ◽  
Town Planning ◽  
Target Groups ◽  
Subjective Perceptions ◽  
Demand Models ◽  
Long Time ◽  
Observed Behaviour ◽  
The Individual ◽  
Transport Mobility

The question of the extent to which the concrete physical environment allows, causes, or even forces certain forms of behaviour to occur has been excluded from social sciences literature for a long time. More recent studies from environmental psychology show that the built environment, filtered by subjective perceptions, very probably influences the experience and actions of individuals. Town planning and transport planning is orientated towards the needs, demands, or simply the observed behaviour of social groups, segments of the population, and target groups of individuals. However, at this level the evidence about whether a spatiospecific determinant should be added to the sociodemographic, sociocultural, or socioeconomic determinants is very inconclusive. This paper investigates the influence of certain types of area on behaviour, and uses about 70000 weekday records at the level of differentiated groups of people. Everyday behaviour of the groups is quantified by their time budgets and daily programmes with broad groupings of out-of-house activities as well as various indicators of transport mobility. This study shows that with given characteristics of the individual and his household a series of behavioural parameters does not vary in space and thus these parameters can be used as input for behaviourally orientated transport demand models and transferred from one planning area to another.

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