scholarly journals Cell tension and mechanical regulation of cell volume

2018 ◽  
Vol 29 (21) ◽  
pp. 0-0 ◽  
Author(s):  
Nicolas Perez Gonzalez ◽  
Jiaxiang Tao ◽  
Nash D. Rochman ◽  
Dhruv Vig ◽  
Evelyn Chiu ◽  
...  
Keyword(s):  
Cell Volume ◽  
Force Balance ◽  
Cell Cortex ◽  
Animal Cells ◽  
Mechanical Tension ◽  
Average Cell ◽  
Physical Size ◽  
Average Cell Volume ◽  
Cell Growth And Proliferation ◽  
Exclusion Method

Animal cells use an unknown mechanism to control their growth and physical size. Here, using the fluorescence exclusion method, we measure cell volume for adherent cells on substrates of varying stiffness. We discover that the cell volume has a complex dependence on substrate stiffness and is positively correlated with the size of the cell adhesion to the substrate. From a mechanical force–balance condition that determines the geometry of the cell surface, we find that the observed cell volume variation can be predicted quantitatively from the distribution of active myosin through the cell cortex. To connect cell mechanical tension with cell size homeostasis, we quantified the nuclear localization of YAP/TAZ, a transcription factor involved in cell growth and proliferation. We find that the level of nuclear YAP/TAZ is positively correlated with the average cell volume. Moreover, the level of nuclear YAP/TAZ is also connected to cell tension, as measured by the amount of phosphorylated myosin. Cells with greater apical tension tend to have higher levels of nuclear YAP/TAZ and a larger cell volume. These results point to a size-sensing mechanism based on mechanical tension: the cell tension increases as the cell grows, and increasing tension feeds back biochemically to growth and proliferation control.

Developmental stages of fetal-type Leydig cells in prepubertal rats

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 213-220
Author(s):  
T. Kuopio ◽  
J. Tapanainen ◽  
L.J. Pelliniemi ◽  
I. Huhtaniemi
Keyword(s):  
Cell Volume ◽  
Leydig Cells ◽  
Developmental Stages ◽  
Neonatal Period ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Adult Type ◽  
Average Cell ◽  
Average Cell Volume ◽  
Fetal Leydig Cells

Fetal Leydig cells were studied in rats during and after the perinatal-neonatal period by comparing changes in morphology, number and volume with changes in testicular steroids and serum luteinizing hormone (LH) concentration. Stereologic examination indicated regression of fetal Leydig cells in testis by showing that their total volume as well as the average cell volume decreased between prenatal day 20 and postnatal day 3. The total number and total volume of cells both increased between postnatal days 3 and 11 but the average cell volume did not change during the same time period. Determination of serum LH showed a close correlation between an increase in LH concentration and increases in total number and volume of cells. The combined number of fetal- and adult-type Leydig cells on day 20 was more than 20 times the number of fetal cells at 3 days of age. Electron microscopic analysis showed that fetal Leydig cells after birth formed conspicuous clusters, which were surrounded by a layer of envelope cells and extracellular material. Occasional dividing fetal Leydig cells and possible precursors of fetal or adult Leydig cells were observed. Mitoses of spindle-shaped pericordal cells were frequent during the neonatal period. During and after the second postnatal week fetal Leydig cells again showed signs of regression, indicated by disintegration of the cell clusters, a decrease in cell size, accumulation of collagen between the cells and a decrease in steroid content per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Morphometric Assessment of Pulmonary Toxicity in the Rodent Lung

1991 ◽  
Vol 19 (4_part_1) ◽  
pp. 428-446 ◽  
Author(s):  
Dallas M. Hyde ◽  
David J. Magliano ◽  
Charles G. Plopper
Keyword(s):  
Cell Volume ◽  
Basal Lamina ◽  
Interstitial Cells ◽  
Nuclear Volume ◽  
Secretory Product ◽  
Average Cell ◽  
Interstitial Volume ◽  
Average Cell Volume ◽  
Morphometric Assessment ◽  
Cell Volumes

An overview of the epithelial and interstitial composition of rat respiratory airways shows complexity and variability. Airway epithelium varies in 1) different airway levels; 2) the types and ultrastructure of cells present; and 3) the abundance, type, and composition of stored secretory product. Unbiased sampling of airways is done using airway microdissection with a specific binary numbering system for airway generation. Vertical sections of selected airways are used to sample epithelium and interstitium. We determine the ratios of the volume of epithelial or interstitial cells to the total epithelial or interstitial volume (Vv). The surface of the epithelial basal lamina to the total epithelial or interstitial volume (Sv) is determined using point and intersection counting with a cycloid grid. Using the selector method on serial plastic sections, we determine the number of epithelial or interstitial cells per volume (Nv) of total epithelium or interstitium. We calculate the number of epithelial or interstitial cells per surface of epithelial basal lamina (Ns) by dividing Nv by Sv where the volumes are the same compartment. We calculate average cell volumes (v̄) for specific epithelial and interstitial cells by dividing the absolute nuclear volume by the ratio of the nucleus to cell volume (Vv). By multiplying the average cell volume (v̄) by the ratio of organellar volume to cell volume (Vv), we calculate the average organellar volume per cell. These unbiased stereological approaches are critical in a quantitative evaluation of toxicological injury of rat tracheobronchial airways.

scholarly journals BIOCHEMICAL AND MORPHOMETRIC PARAMETERS OF SOME ORGANS AND TISSUES OF HYBRID TILAPIA (OREOCHROMIS SPP.) FOR GROWING WITH USE OF PREPARATION ES-2

2018 ◽  
pp. 113-117
Author(s):  
Svetlana Vladimirovna Kotelnikova ◽  
Andrey Vyacheslavovich Kotelnikov ◽  
Alexander Nickolaevich Nevalennyy ◽  
Sergey Vladimirovich Ponomarev ◽  
Yulia Mikhailovna Shirina
Keyword(s):  
Lipid Peroxidation ◽  
Cell Volume ◽  
Control Group ◽  
Fish Feed ◽  
Prooxidant Effect ◽  
Average Cell ◽  
Liver Nuclei ◽  
Average Cell Volume ◽  
Experimental Group ◽  
Volume Decrease

The article studies the effect of addition into the feed of Sapropel extract (ES-2 preparation) on the intensity of lipid peroxidation in the liver and gills of hybrid tilapia ( Oreochromis spp. ), as well as on the morphofunctional state of its liver. Sapropel extract caused a decrease in the content of TBA-reactants in the tissues of tilapia liver by 17% compared to the control group. In gills the bioadditive resulted in the increased content of peroxide products by 24%. The introduction of ES-2 in fish feed resulted in reduction of spontaneous and ascorbate-dependent lipid peroxidation rate in the liver by 18%. In the gills of fish, under the influence of Sapropel, the rate of spontaneous lipid peroxidation increased by 27%, the rate of ascorbate-dependent lipid peroxidation - by 23%. The change in the intensity of peroxide processes under the influence of the fodder additive in fish organs is tissue-specific: antioxidant effect was recorded in the liver, prooxidant effect was observed in the gills. The introduction of the Sapropel extract does not lead to a change in the volume of liver nuclei in the test groups of tilapia, while the average cell volume in the experimental group was 37% lower than in the control group. The decrease in cell volume led to the increase in the nuclear-cytoplasmic ratio by 1.9 times in the experimental group compared to the control group. Hepatocyte cytoplasm volume decrease and nuclear-cytoplasmic ratio increase due to addition of ES-2 preparation into productive feed of hybrid tilapia would indicate a rise of functional activity of liver cells.

scholarly journals Mechanism of the formation of contractile ring in dividing cultured animal cells. II. Cortical movement of microinjected actin filaments.

1990 ◽  
Vol 111 (5) ◽  
pp. 1905-1911 ◽  
Author(s):  
L G Cao ◽  
Y L Wang
Keyword(s):  
Actin Filaments ◽  
Average Rate ◽  
Rat Kidney ◽  
Equatorial Region ◽  
Cell Cortex ◽  
Polar Regions ◽  
Cortical Actin ◽  
Animal Cells ◽  
Contractile Ring ◽  
Directional Movement

The contractile ring in dividing animal cells is formed primarily through the reorganization of existing actin filaments (Cao, L.-G., and Y.-L. Wang. 1990. J. Cell Biol. 110:1089-1096), but it is not clear whether the process involves a random recruitment of diffusible actin filaments from the cytoplasm, or a directional movement of cortically associated filaments toward the equator. We have studied this question by observing the distribution of actin filaments that have been labeled with fluorescent phalloidin and microinjected into dividing normal rat kidney (NRK) cells. The labeled filaments are present primarily in the cytoplasm during prometaphase and early metaphase, but become associated extensively with the cell cortex 10-15 min before the onset of anaphase. This process is manifested both as an increase in cortical fluorescence intensity and as movements of discrete aggregates of actin filaments toward the cortex. The concentration of actin fluorescence in the equatorial region, accompanied by a decrease of fluorescence in polar regions, is detected 2-3 min after the onset of anaphase. By directly tracing the distribution of aggregates of labeled actin filaments, we are able to detect, during anaphase and telophase, movements of cortical actin filaments toward the equator at an average rate of 1.0 micron/min. Our results, combined with previous observations, suggest that the organization of actin filaments during cytokinesis probably involves an association of cytoplasmic filaments with the cortex, a movement of cortical filaments toward the cleavage furrow, and a dissociation of filaments from the equatorial cortex.

scholarly journals Fission yeast myosin Myo2 is down-regulated in actin affinity by light chain phosphorylation

2017 ◽  
Vol 114 (35) ◽  
pp. E7236-E7244 ◽  
Author(s):  
Luther W. Pollard ◽  
Carol S. Bookwalter ◽  
Qing Tang ◽  
Elena B. Krementsova ◽  
Kathleen M. Trybus ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Light Chain ◽  
Force Production ◽  
Class Ii ◽  
Cell System ◽  
Cell Cortex ◽  
Animal Cells ◽  
Contractile Ring ◽  
Biophysical Studies

Studies in fission yeast Schizosaccharomyces pombe have provided the basis for the most advanced models of the dynamics of the cytokinetic contractile ring. Myo2, a class-II myosin, is the major source of tension in the contractile ring, but how Myo2 is anchored and regulated to produce force is poorly understood. To enable more detailed biochemical/biophysical studies, Myo2 was expressed in the baculovirus/Sf9 insect cell system with its two native light chains, Rlc1 and Cdc4. Milligram yields of soluble, unphosphorylated Myo2 were obtained that exhibited high actin-activated ATPase activity and in vitro actin filament motility. The fission yeast specific chaperone Rng3 was thus not required for expression or activity. In contrast to nonmuscle myosins from animal cells that require phosphorylation of the regulatory light chain for activation, phosphorylation of Rlc1 markedly reduced the affinity of Myo2 for actin. Another unusual feature of Myo2 was that, unlike class-II myosins, which generally form bipolar filamentous structures, Myo2 showed no inclination to self-assemble at approximately physiological salt concentrations, as analyzed by sedimentation velocity ultracentrifugation. This lack of assembly supports the hypothesis that clusters of Myo2 depend on interactions at the cell cortex in structural units called nodes for force production during cytokinesis.

scholarly journals Role of glutathione on cell adhesion and volume.

2021 ◽  
Author(s):  
Alain Geloen ◽  
Emmanuelle Danty
Keyword(s):  
Cell Adhesion ◽  
Cell Volume ◽  
Reduced Glutathione ◽  
Self Regulation ◽  
Cell Types ◽  
Self Control ◽  
Animal Cells ◽  
Cellular Processes ◽  
Proliferation And Apoptosis ◽  
Glutamylcysteine Synthetase

Glutathione is the most abundant thiol in animal cells. Reduced glutathione (GSH) is a major intracellular antioxidant neutralizing free radicals and detoxifying electrophiles. It plays important roles in many cellular processes, including cell differentiation, proliferation, and apoptosis. In the present study we demonstrate that extracellular concentration of reduced glutathione markedly increases cell volume within few hours, in a dose-response manner. Pre-incubation of cells with BSO, the inhibitor of 7-glutamylcysteine synthetase, responsible for the first step in intracellular glutathione synthesis did not change the effect of reduced glutathione on cell volume suggesting a mechanism limited to the interaction of extracellular reduced glutathione on cell membrane. Results show that reduced GSH decreases cell adhesion resulting in an increased cell volume. Since many cell types are able to transport of GSH out, the present results suggest that this could be a fundamental self-regulation of cell volume, giving the cells a self-control on their adhesion proteins.

Interactions of cell volume, membrane potential, and membrane transport parameters

1980 ◽  
Vol 238 (5) ◽  
pp. C196-C206 ◽  
Author(s):  
E. Jakobsson
Keyword(s):  
Membrane Potential ◽  
Cell Volume ◽  
Membrane Transport ◽  
Numerical Solutions ◽  
Transport Equations ◽  
Time Varying ◽  
Transport Parameters ◽  
Animal Cells ◽  
Analytic Expressions ◽  
Solute Species

Equations have been written and solved that describe for animal cells the relationships among membrane transport, cell volume, membrane potential, and distribution of permeant solute. The essential system consists of n + 2 equations, where n is the number of permeant solute species. The n of the equations are the n transport equations for the permeant species, one for each species. The other two equations are statements of 1) the condition for bulk electroneutrality inside the cell and 2) the condition for isotonicity between the interior and exterior of the cell. Numerical solutions have been obtained in both the steady-state and time-varying cases for transport equations that are physically and phenomenologically reasonable. In addition to numerical solutions analytic expressions are presented that show the ranges of membrane parameters essential for volume regulation; for values of membrane parameters beyond explicitly defined bounds, the equations do not have real, positive solutions for cell volume.

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