The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Jiansheng Liang - One of the best experts on this subject based on the ideXlab platform.

  • Initiation and regulation of water deficit‐induced abscisic acid accumulation in maize leaves and roots: Cellular Volume and water relations
    Journal of Experimental Botany, 2017
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit‐induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air‐drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration‐induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

  • initiation and regulation of water deficit induced abscisic acid accumulation in maize leaves and roots Cellular Volume and water relations
    Journal of Experimental Botany, 2001
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit-induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air-drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration-induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

Hongyuan Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Controlling Cellular Volume via Mechanical and Physical Properties of Substrate.
    Biophysical journal, 2018
    Co-Authors: Kenan Xie, Yuehua Yang, Hongyuan Jiang
    Abstract:

    Abstract The mechanical and physical properties of substrate play a crucial role in regulating many cell functions and behaviors. However, how these properties affect cell Volume is still unclear. Here, we show that an increase in substrate stiffness, available spread area, or effective adhesion energy density results in a remarkable cell Volume decrease (up to 50%), and the dynamic cell spreading process is also accompanied by dramatic cell Volume decrease. Further, studies of ion channel inhibition and osmotic shock suggest that these Volume decreases are due to the efflux of water and ions. We also show that disrupting cortex contractility leads to bigger cell Volume. Collectively, these results reveal the "mechanism of adhesion-induced compression of cells," i.e., stronger interaction between cell and substrate leads to higher actomyosin contractility, expels water and ions, and thus decreases cell Volume.

  • Cellular Volume regulation and substrate stiffness modulate the detachment dynamics of adherent cells
    Journal of The Mechanics and Physics of Solids, 2017
    Co-Authors: Yuehua Yang, Hongyuan Jiang
    Abstract:

    Abstract Quantitative characterizations of cell detachment are vital for understanding the fundamental mechanisms of cell adhesion. Experiments have found that cell detachment shows strong rate dependence, which is mostly attributed to the binding-unbinding kinetics of receptor-ligand bond. However, our recent study showed that the Cellular Volume regulation can significantly regulate the dynamics of adherent cell and cell detachment. How this Cellular Volume regulation contributes to the rate dependence of cell detachment remains elusive. Here, we systematically study the role of Cellular Volume regulation in the rate dependence of cell detachment by investigating the cell detachments of nonspecific adhesion and specific adhesion. We find that the Cellular Volume regulation and the bond kinetics dominate the rate dependence of cell detachment at different time scales. We further test the validity of the traditional Johnson–Kendall–Roberts (JKR) contact model and the detachment model developed by Wyart and Gennes et al (W–G model). When the cell Volume is changeable, the JKR model is not appropriate for both the detachments of convex cells and concave cells. The W–G model is valid for the detachment of convex cells but is no longer applicable for the detachment of concave cells. Finally, we show that the rupture force of adherent cells is also highly sensitive to substrate stiffness, since an increase in substrate stiffness will lead to more associated bonds. These findings can provide insight into the critical role of cell Volume in cell detachment and might have profound implications for other adhesion-related physiological processes.

  • Shape and Dynamics of Adhesive Cells: Mechanical Response of Open Systems.
    Physical review letters, 2017
    Co-Authors: Yuehua Yang, Hongyuan Jiang
    Abstract:

    Cell adhesion is an essential biological process. However, previous theoretical and experimental studies ignore a key variable, the changes of Cellular Volume and pressure, during the dynamic adhesion process. Here, we treat cells as open systems and propose a theoretical framework to investigate how the exchange of water and ions with the environment affects the shape and dynamics of cells adhered between two adhesive surfaces. We show that adherent cells can be either stable (convex or concave) or unstable (spontaneous rupture or collapse) depending on the adhesion energy density, the cell size, the separation of two adhesive surfaces, and the stiffness of the flexible surface. Strikingly, we find that the unstable states vanish when Cellular Volume and pressure are constant. We further show that the detachments of convex and concave cells are very different. The mechanical response of adherent cells is mainly determined by the competition between the loading rate and the regulation of the Cellular Volume and pressure. Finally, we show that as an open system the detachment of adherent cells is also significantly influenced by the loading history. Thus, our findings reveal a major difference between living cells and nonliving materials.

  • Cellular Pressure and Volume Regulation and Implications for Cell Mechanics
    Biophysical journal, 2013
    Co-Authors: Hongyuan Jiang, Sean X. Sun
    Abstract:

    In eukaryotic cells, small changes in cell Volume can serve as important signals for cell proliferation, death, and migration. Volume and shape regulation also directly impacts the mechanics of cells and tissues. Here, we develop a mathematical model of Cellular Volume and pressure regulation, incorporating essential elements such as water permeation, mechanosensitive channels, active ion pumps, and active stresses in the cortex. The model can fully explain recent experimental data, and it predicts Cellular Volume and pressure for several models of cell cortical mechanics. Moreover, we show that when cells are subjected to an externally applied load, such as in an atomic force microscopy indentation experiment, active regulation of Volume and pressure leads to a complex Cellular response. Instead of the passive mechanics of the cortex, the observed cell stiffness depends on several factors working together. This provides a mathematical explanation of rate-dependent response of cells under force.

Wensuo Jia - One of the best experts on this subject based on the ideXlab platform.

  • Initiation and regulation of water deficit‐induced abscisic acid accumulation in maize leaves and roots: Cellular Volume and water relations
    Journal of Experimental Botany, 2017
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit‐induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air‐drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration‐induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

  • initiation and regulation of water deficit induced abscisic acid accumulation in maize leaves and roots Cellular Volume and water relations
    Journal of Experimental Botany, 2001
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit-induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air-drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration-induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

Jianhua Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Initiation and regulation of water deficit‐induced abscisic acid accumulation in maize leaves and roots: Cellular Volume and water relations
    Journal of Experimental Botany, 2017
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit‐induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air‐drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration‐induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

  • initiation and regulation of water deficit induced abscisic acid accumulation in maize leaves and roots Cellular Volume and water relations
    Journal of Experimental Botany, 2001
    Co-Authors: Wensuo Jia, Jianhua Zhang, Jiansheng Liang
    Abstract:

    Water deficit-induced ABA accumulation in relation to Cellular water relations was investigated in maize root and leaf tissues. While polyethylene glycol (PEG) treatment led to a significant increase of ABA content in both root and leaf tissues, ethylene glycol (EG), a permeable monomer of PEG, had no effect on ABA accumulation at similar or much lower osmotic potentials. A rapid and massive accumulation of ABA in leaf tissues occurred at a specific threshold of PEG 6000 concentration, about 20% (w/v), and closely coincided with the start of the tissue weight loss and the obvious decrease of Cellular osmotic potential. Pretreatment with EG lowered the cell sap osmotic potential and also lowered the capability of both root and leaf tissues to accumulate ABA in response to further air-drying or PEG treatment. When samples were dehydrated and incubated under pressure, a method to maintain high water potential and pressure potential during dehydration, ABA accumulation was similar to those dehydrated and incubated under atmospheric pressure. Such results suggest that both the absolute water potential and pressure potential per se had no direct effects on the dehydration-induced ABA accumulation. The results have provided evidence that the initiation of ABA accumulation is related to the weight loss of tissues or changes in Cellular Volume rather than the cell water relation parameters, and the capability of ABA accumulation can be regulated by Cellular osmotic potential.

Sean X. Sun - One of the best experts on this subject based on the ideXlab platform.

  • Cell-Substrate Interaction Determines Cellular Volume and Shape
    Biophysical Journal, 2016
    Co-Authors: Jiaxiang Tao, Sean X. Sun
    Abstract:

    Multiple experimental results have shown eukaryotic cells are able to respond to its mechanical environment. Such responds are not only crucial during cell migration, polarization and tissue formation, but also determining Cellular Volume and shape.In this study, we show a simple mechanical force balance, coupled with previously-purposed chemical model on Rho GTPase activation, is able to predict the Cellular shape when cells spreading on substrates with different sizes and/or stiffness, indicating the importance of mechanical forces that regulates different cell activities, including myosin activities, Cellular Volume, as well as traction stresses between cell and substrate. Moreover, if cell is placed in the growth medium, such mechanical signal may trigger cell division.With previously developed FRET pair, we are also able to observe RhoA activity during cell spreading experimentally, which is a crucial prove to our purposed model.

  • Cellular Pressure and Volume Regulation and Implications for Cell Mechanics
    Biophysical journal, 2013
    Co-Authors: Hongyuan Jiang, Sean X. Sun
    Abstract:

    In eukaryotic cells, small changes in cell Volume can serve as important signals for cell proliferation, death, and migration. Volume and shape regulation also directly impacts the mechanics of cells and tissues. Here, we develop a mathematical model of Cellular Volume and pressure regulation, incorporating essential elements such as water permeation, mechanosensitive channels, active ion pumps, and active stresses in the cortex. The model can fully explain recent experimental data, and it predicts Cellular Volume and pressure for several models of cell cortical mechanics. Moreover, we show that when cells are subjected to an externally applied load, such as in an atomic force microscopy indentation experiment, active regulation of Volume and pressure leads to a complex Cellular response. Instead of the passive mechanics of the cortex, the observed cell stiffness depends on several factors working together. This provides a mathematical explanation of rate-dependent response of cells under force.