Diffusion in the aqueous compartment

Andrea Marie Mastro, A. D. Keith

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

Measurements of diffusion of molecules in cells can provide information about cytoplasmic viscosity and structure. In a series of studies electron-spin resonance was used to measure the diffusion of a small spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity of the cytoplasm from both rotational and translational motion would distinguish between the effects of viscosity and structure on diffusion. The diffusion constant measured in several cell lines averaged 3.3 x 10-6 cm2/s. It was greater in growing cells and in cells treated with cytochalasin B than in quiescent cells. The viscosity of the cytoplasm calculated from the translational diffusion constant or the rotational correlation time was 2.0-3.0 centipoise, about two to three times that of the spin label in water. Therefore, over the dimensions measured by the technique, 50-100 Å, solvent viscosity appears to be the major determinant of particle movement in cells under physiologic conditions. However, when cells were subjected to hypertonic conditions, the translational motion of the spin label decreased threefold, whereas the rotational motion changed by <20%. These data suggest that the decrease in cell volume under hypertonic conditions is accompanied by an increase in cytoplasmic barriers and a decrease in the space between existing cytoplasmic components without a significant increase in viscosity in the aqueous phase. In addition, a comparison of reported diffusion values of a variety of molecules in water and in cells indicates that cytoplasmic structure plays an important role in the diffusion of proteins such as bovine serum albumin.

Original languageEnglish (US)
JournalJournal of Cell Biology
Volume99
Issue number1 II
StatePublished - Jan 1 1984

Fingerprint

Viscosity
Spin Labels
Cytoplasmic Structures
Cytoplasm
Cytochalasin B
Water
Electron Spin Resonance Spectroscopy
Bovine Serum Albumin
Cell Size
Cell Movement
Cell Line
Proteins

All Science Journal Classification (ASJC) codes

  • Cell Biology

Cite this

Mastro, A. M., & Keith, A. D. (1984). Diffusion in the aqueous compartment. Journal of Cell Biology, 99(1 II).
Mastro, Andrea Marie ; Keith, A. D. / Diffusion in the aqueous compartment. In: Journal of Cell Biology. 1984 ; Vol. 99, No. 1 II.
@article{16eddb9a66db4e8e8717d81f2db485a0,
title = "Diffusion in the aqueous compartment",
abstract = "Measurements of diffusion of molecules in cells can provide information about cytoplasmic viscosity and structure. In a series of studies electron-spin resonance was used to measure the diffusion of a small spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity of the cytoplasm from both rotational and translational motion would distinguish between the effects of viscosity and structure on diffusion. The diffusion constant measured in several cell lines averaged 3.3 x 10-6 cm2/s. It was greater in growing cells and in cells treated with cytochalasin B than in quiescent cells. The viscosity of the cytoplasm calculated from the translational diffusion constant or the rotational correlation time was 2.0-3.0 centipoise, about two to three times that of the spin label in water. Therefore, over the dimensions measured by the technique, 50-100 {\AA}, solvent viscosity appears to be the major determinant of particle movement in cells under physiologic conditions. However, when cells were subjected to hypertonic conditions, the translational motion of the spin label decreased threefold, whereas the rotational motion changed by <20{\%}. These data suggest that the decrease in cell volume under hypertonic conditions is accompanied by an increase in cytoplasmic barriers and a decrease in the space between existing cytoplasmic components without a significant increase in viscosity in the aqueous phase. In addition, a comparison of reported diffusion values of a variety of molecules in water and in cells indicates that cytoplasmic structure plays an important role in the diffusion of proteins such as bovine serum albumin.",
author = "Mastro, {Andrea Marie} and Keith, {A. D.}",
year = "1984",
month = "1",
day = "1",
language = "English (US)",
volume = "99",
journal = "Journal of Cell Biology",
issn = "0021-9525",
publisher = "Rockefeller University Press",
number = "1 II",

}

Mastro, AM & Keith, AD 1984, 'Diffusion in the aqueous compartment', Journal of Cell Biology, vol. 99, no. 1 II.

Diffusion in the aqueous compartment. / Mastro, Andrea Marie; Keith, A. D.

In: Journal of Cell Biology, Vol. 99, No. 1 II, 01.01.1984.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Diffusion in the aqueous compartment

AU - Mastro, Andrea Marie

AU - Keith, A. D.

PY - 1984/1/1

Y1 - 1984/1/1

N2 - Measurements of diffusion of molecules in cells can provide information about cytoplasmic viscosity and structure. In a series of studies electron-spin resonance was used to measure the diffusion of a small spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity of the cytoplasm from both rotational and translational motion would distinguish between the effects of viscosity and structure on diffusion. The diffusion constant measured in several cell lines averaged 3.3 x 10-6 cm2/s. It was greater in growing cells and in cells treated with cytochalasin B than in quiescent cells. The viscosity of the cytoplasm calculated from the translational diffusion constant or the rotational correlation time was 2.0-3.0 centipoise, about two to three times that of the spin label in water. Therefore, over the dimensions measured by the technique, 50-100 Å, solvent viscosity appears to be the major determinant of particle movement in cells under physiologic conditions. However, when cells were subjected to hypertonic conditions, the translational motion of the spin label decreased threefold, whereas the rotational motion changed by <20%. These data suggest that the decrease in cell volume under hypertonic conditions is accompanied by an increase in cytoplasmic barriers and a decrease in the space between existing cytoplasmic components without a significant increase in viscosity in the aqueous phase. In addition, a comparison of reported diffusion values of a variety of molecules in water and in cells indicates that cytoplasmic structure plays an important role in the diffusion of proteins such as bovine serum albumin.

AB - Measurements of diffusion of molecules in cells can provide information about cytoplasmic viscosity and structure. In a series of studies electron-spin resonance was used to measure the diffusion of a small spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity of the cytoplasm from both rotational and translational motion would distinguish between the effects of viscosity and structure on diffusion. The diffusion constant measured in several cell lines averaged 3.3 x 10-6 cm2/s. It was greater in growing cells and in cells treated with cytochalasin B than in quiescent cells. The viscosity of the cytoplasm calculated from the translational diffusion constant or the rotational correlation time was 2.0-3.0 centipoise, about two to three times that of the spin label in water. Therefore, over the dimensions measured by the technique, 50-100 Å, solvent viscosity appears to be the major determinant of particle movement in cells under physiologic conditions. However, when cells were subjected to hypertonic conditions, the translational motion of the spin label decreased threefold, whereas the rotational motion changed by <20%. These data suggest that the decrease in cell volume under hypertonic conditions is accompanied by an increase in cytoplasmic barriers and a decrease in the space between existing cytoplasmic components without a significant increase in viscosity in the aqueous phase. In addition, a comparison of reported diffusion values of a variety of molecules in water and in cells indicates that cytoplasmic structure plays an important role in the diffusion of proteins such as bovine serum albumin.

UR - http://www.scopus.com/inward/record.url?scp=0021228382&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021228382&partnerID=8YFLogxK

M3 - Article

C2 - 6086666

AN - SCOPUS:0021228382

VL - 99

JO - Journal of Cell Biology

JF - Journal of Cell Biology

SN - 0021-9525

IS - 1 II

ER -

Mastro AM, Keith AD. Diffusion in the aqueous compartment. Journal of Cell Biology. 1984 Jan 1;99(1 II).