Intracellular viscosity: Methods of measurement and role in metabolism

Puchkov, E. O.

doi:10.1134/s1990747813050140

Cited by 79 publications

(76 citation statements)

References 77 publications

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“…For flow boundary conditions, fluid flow is imposed on one end of the tube in flow boundary conditions. Parameters: Simulations parameters were µ = 1.5 × 10 −3 Pa s for the viscosity of the cytoplasm [40], a * = 100 µm for the radius of the viscoelastic tube, E = 10 Pa for its effective stiffness (assuming a Young's modulus of 100 Pa [41], [42] and a thickness of the tubes of h = a * /10), η = E × 24s for its effective viscosity [41], [43], [44], κ = 100E for the non-linear elasticity, σ 0 = 3E for the active stress [42], [45], D = 3.33 × 10 −10 m 2 s −1 [46], [47] for the diffusion of the tension activator in the cytoplasm, a * c * /(2p c ) = a * /(2d c ) = 96 s [27], [28] for the time-scale of its regulation, c = 0.3 for the threshold of its stretch-activated supply, and σ = 2 for the stretch-inhibition of the active stress. Other parameters were eliminated in the non-dimensional equations.…”

Section: Methodsmentioning

confidence: 99%

Oscillatory fluid flow drives scaling of contraction wave with system size

Julien

Alim

2018

Proc. Natl. Acad. Sci. U.S.A.

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Flows over remarkably long distances are crucial to the functioning of many organisms, across all kingdoms of life. Coordinated flows are fundamental to power deformations, required for migration or development, or to spread resources and signals. A ubiquitous mechanism to generate flows, particularly prominent in animals and amoeba, is acto-myosin cortex driven mechanical deformations that pump the fluid enclosed by the cortex. Yet, it is unclear how cortex dynamics can self-organize to give rise to coordinated flows across the largely varying scales of biological systems. Here, we develop a mechanochemical model of acto-myosin cortex mechanics coupled to a contraction-triggering, soluble chemical. The chemical itself is advected with the flows generated by the cortex driven deformations of the tubular-shaped cell. The theoretical model predicts a dynamic instability giving rise to stable patterns of cortex contraction waves and oscillatory flows. Surprisingly, simulated patterns extend beyond the intrinsic length scale of the dynamic instability -scaling with system size instead. Patterns appear randomly but can be robustly generated in a growing system or by flow-generating boundary conditions. We identify oscillatory flows as the key for the scaling of contraction waves with system size. Our work shows the importance of active flows in biophysical models of patterning, not only as a regulating input or an emergent output, but rather as a full part of a self-organized machinery. Contractions and fluid flows are observed in all kinds of organisms, so this concept is likely to be relevant for a broad class of systems.

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Section: Methodsmentioning

confidence: 99%

Oscillatory fluid flow drives scaling of contraction wave with system size

Julien

Alim

2018

Proc. Natl. Acad. Sci. U.S.A.

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“…Apparent viscosity values in the vacuoles of the cells, computed by the Einstein-Smoluchowski equation using the obtained data, were found to be 2.16 ± 0.60, 2.52 ± 0.63, 3.32 ± 0.9 and 11.3 ± 1.7 cP. (More on intracellular viscosity see the review [95]).…”

Section: Single Cellsmentioning

confidence: 84%

Image Analysis in Microbiology: A Review

Pushchino¹

2016

JCC

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This review is focused on using computer image analysis as a means of objective and quantitative characterizing optical images of the macroscopic (e.g. microbial colonies) and the microscopic (e.g. single cell) objects in the microbiological research. This is the way of making many visual inspection assays more objective and less time and labor consuming. Also, it can provide new visually inaccessible information on relation between some optical parameters and various biological features of the microbial cultures. Of special interest is application of image analysis in fluorescence microscopy as it opens new ways of using fluorescence based methodology for single microbial cell studies. Examples of using image analysis in the studies of both the macroscopic and the microscopic microbiological objects obtained by various imaging techniques are presented and discussed.

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“…To reproduce cellular viscoelastic behaviour we implemented viscoelastic domain based on the Kelvin–Voigt model. The material parameters were defined in accordance with the range reported for blood platelets, that is the elastic modulus 10 kPa and the viscosity 0.01 Pa·s [ 30 , 31 ]. The computational domains are schematically shown in Figure 10 .…”

Section: Resultsmentioning

confidence: 99%

Topology Challenge for the Assessment of Living Cell Deposits with Shear Bulk Acoustic Biosensor

et al. 2020

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Shear bulk acoustic type of resonant biosensors, such as the quartz crystal microbalance (QCM), give access to label-free in-liquid analysis of surface interactions. The general understanding of the sensing principles was inherited from past developments in biofilms measurements and applied to cells while keeping the same basic assumptions. Thus, the biosensor readouts are still quite often described using ‘mass’ related terminology. This contribution aims to show that assessment of cell deposits with acoustic biosensors requires a deep understanding of the sensor transduction mechanism. More specifically, the cell deposits should be considered as a structured viscoelastic load and the sensor response depends on both material and topological parameters of the deposits. This shifts the paradigm of acoustic biosensor away from the classical mass loading perspective. As a proof of the concept, we recorded QCM frequency shifts caused by blood platelet deposits on a collagen surface under different rheological conditions and observed the final deposit shape with atomic force microscopy (AFM). The results vividly demonstrate that the frequency shift is highly impacted by the platelet topology on the bio-interface. We support our findings with numerical simulations of viscoelastic unstructured and structured loads in liquid. Both experimental and theoretical studies underline the complexity behind the frequency shift interpretation when acoustic biosensing is used with cell deposits.

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Intracellular viscosity: Methods of measurement and role in metabolism

Cited by 79 publications

References 77 publications

Oscillatory fluid flow drives scaling of contraction wave with system size

Oscillatory fluid flow drives scaling of contraction wave with system size

Image Analysis in Microbiology: A Review

Topology Challenge for the Assessment of Living Cell Deposits with Shear Bulk Acoustic Biosensor

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