Related Experiment Video
Updated: May 23, 2026
08:08
Monitoring the Effect of Osmotic Stress on Secretory Vesicles and Exocytosis
Published on: February 19, 2018
Regulatory volume decrease in COS-7 cells at 22 °C and its influence on the Boyle van't Hoff relation and the
1Fundamental and Applied Cryobiology Group, Department of Biochemistry, Cellular and Molecular Biology, the University of Tennessee, Knoxville, TN 37932, USA. diana.peckys@inm-gmbh.de
Cryobiology
|April 11, 2012
Summary
Regulatory volume decrease (RVD) in COS-7 cells significantly impacts cryobiological analyses. This energy-dependent cell shrinkage inflates the calculated solid cell fraction (b), necessitating RVD assessment before osmotic parameter measurements.
Area of Science:
- Cellular Physiology
- Biophysics
- Cryobiology
Background:
- Cryobiological studies commonly assume water movement and cell volume are governed solely by water chemical potentials.
- This assumption leads to the Boyle van't Hoff (BvH) law, relating cell volume to osmolality and yielding a solid fraction (b).
- Many cells exhibit regulatory volume decrease (RVD), an energy-dependent shrinkage response to swelling.
Purpose of the Study:
- To investigate the impact of regulatory volume decrease (RVD) on Boyle van't Hoff (BvH) law parameters in COS-7 cells.
- To determine the accuracy of cryobiological analyses when RVD is not accounted for.
Main Methods:
- Observed RVD in COS-7 cells.
- Measured cell volumes and osmolality under varying conditions.
- Calculated the fractional solid cell volume (b) using BvH plots.
Main Results:
- COS-7 cells exhibit strong RVD.
- Uncorrected RVD led to a calculated solid fraction (b) that was 60% higher than the actual value (0.48 vs. 0.30).
- Short exposure times were necessary to minimize RVD's influence on measurements.
Conclusions:
- Regulatory volume decrease (RVD) significantly skews cryobiological osmotic parameter measurements.
- Accurate determination of cell solid fraction (b) requires accounting for RVD.
- Pre-analysis assessment of volume regulatory mechanisms is crucial for reliable cryobiological data.
Related Concept Videos
02:40Osmosis and Osmotic Pressure of Solutions
A number of natural and synthetic materials exhibit selective permeation, meaning that only molecules or ions of a certain size, shape, polarity, charge, and so forth, are capable of passing through (permeating) the material. Biological cell membranes provide elegant examples of selective permeation in nature, while dialysis tubing used to remove metabolic wastes from blood is a more simplistic technological example. Regardless of how they may be fabricated, these materials are generally...
01:26Osmotic Pressure
Osmosis is a process where solvent molecules move toward a solution through a semipermeable membrane. As the solution dilutes due to the entry of solvent, it expands. This expansion increases the hydrostatic pressure of the solution. When the hydrostatic pressure equals the osmotic pressure, osmosis stops.Osmotic pressure, denoted by Π, is the minimum pressure needed to prevent the solvent from passing into the solution by osmosis. The van 't Hoff equation calculates the osmotic pressure of an...
03:19Gas Laws: Boyle's, Gay-Lussac, Charles', Avogadro's, and Ideal Gas Law
Through experiments, scientists established the mathematical relationships between pairs of variables, such as pressure and temperature, pressure and volume, volume and temperature, and volume and moles, that hold for an ideal gas.
03:12Freezing Point Depression and Boiling Point Elevation
Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
01:24Freezing Point Depression and Boiling Point Elevation
When a non-volatile solute is added to a pure solvent, it results in the lowering of the freezing point of the solvent. This phenomenon is called freezing point depression. The extent to which the freezing point is lowered depends on the molality of the solute -the number of moles of solute per kilogram of solvent and the cryoscopic constant of the solvent.From the plot of chemical potential, μ, against temperature, it is evident that the μ of both solid and liquid solvents decrease with...
04:01Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation
Thus far, the ideal gas law, PV = nRT, has been applied to a variety of different types of problems, ranging from reaction stoichiometry and empirical and molecular formula problems to determining the density and molar mass of a gas. However, the behavior of a gas is often non-ideal, meaning that the observed relationships between its pressure, volume, and temperature are not accurately described by the gas laws.