Electron spin resonance studies of changes in membrane fluidity of Chinese hamster ovary cells during the cell cycle

Lai, Ching‐San; Hopwood, Larry E.; Swartz, Harold M.

doi:10.1016/0005-2736(80)90294-1

Cited by 50 publications

(21 citation statements)

References 22 publications

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“…Growing cells in culture are passing constantly through the cell cycle implying that a standard (nonsynchronized) culture actually represents a physiologically mixed population of cells with variations in cell size, DNA content, protein complement [Lewin, 1997], expression of cell surface molecules [Matsui et al, 1986;Cassanelli et al, 1991;Rostagno et al, 1996] as well as membrane rigidity [Lai et al, 1980] all of which may affect the ability of the virus to enter into the cell, or affect the efficiency of the production of viral progeny.…”

Section: Discussionmentioning

confidence: 99%

Internalization of the dengue virus is cell cycle modulated in HepG2, but not vero cells

Phoolcharoen¹,

Smith²

2004

Journal of Medical Virology

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While many studies have investigated the relationship between cell type and dengue virus infection, no study to date has examined the effect of cell physiology on permissiveness to infection. Unsynchronized and artificially synchronized cell populations at different stages of the cell cycle of two cell types (Vero and HepG2) were examined for permissiveness to infection by two dengue virus serotypes (serotypes 2 and 3) by determining both the levels of virus produced as well as the percentage of cells infected. Vero cells showed no significant differences between either viral production or percentage of cells infected as compared to unsynchronized cells for any of the phases investigated, although production of virus (for both serotypes 2 and 3) was somewhat lower for cells infected during S phase. In contrast, HepG2 cells were significantly more permissive for both infection and virus production in the G(2) phase as compared to other phases examined and serotype differences in permissiveness to infection were noted with cells in the M phase of the cell cycle. These results suggest that the cell cycle may be a mediator of cell permissiveness in some cell types.

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Section: Discussionmentioning

confidence: 99%

Internalization of the dengue virus is cell cycle modulated in HepG2, but not vero cells

Phoolcharoen¹,

Smith²

2004

Journal of Medical Virology

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“…CHO cells maintained in monolayer culture from frozen stocks for several years in this laboratory were used because they are well characterized. The procedures for culturing CHO cells, either in monolayer or in suspension, and for synchronization have been described (11). The mitotic index ofcells in mitosis was about 97% and did not change appreciably during the ESR measurement.…”

Section: Methodsmentioning

confidence: 99%

ESR studies of O2 uptake by Chinese hamster ovary cells during the cell cycle.

Lai¹,

Hopwood²,

Hyde³

et al. 1982

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

110

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Magnetic interactions between dissolved oxygen and nitroxide radical spin probes lead to broadening of the ESR lines. We have used a closed-chamber method based on this property to determine the maximum rate of 02 uptake per cell (Vm. per cell) in cultured mammalian cells. A suitable spin probe and a cell suspension are mixed in an aerated medium, and the rate of disappearance of dissolved 02 is measured. The effects of temperature, pH, and microwave power on the determination of dissolved oxygen in solution were studied. For Most mammalian cells are aerobic, and dissolved oxygen is vital for their growth. Elucidation of the mechanism of 02 uptake during the cell cycle is probably fundamental to the complete understanding of cell growth and cell division.There have been several reports on the measurement of 02 uptake during the cell cycle (1-4). Most previous research has been done on dividing egg cells by using the Cartesian diver technique (1) and on yeast cells by using the Clark electrode (2). To our knowledge, only two reports have appeared concerning 02 uptake by cultured mammalian cells during the cell cycle (3,4). One of the obstacles is that the existing techniques for measurement of 02 uptake by cultured mammalian cells require large amounts of.cells for each measurement, making it difficult to study mitotically synchronized cells. Most chemical means of synchronization induce multiple biochemical perturbations that obscure the interpretations of any 02 uptake measurements.It is well known that the interaction ofdissolved oxygen molecules and nitroxide free radicals through Heisenberg spin-exchange causes broadening of the ESR lines (5-7). With a suitable spin probe, this property can be used to quantitate 02 concentrations in solution (8)(9)(10).In this report, we describe an ESR closed-chamber method for determining the 02 uptake by cultured mammalian cells.Basically, a spin probe and a cell suspension are mixed in an aerated medium and the rate of disappearance of 02 is measured. Because a relatively small number of cells is required for each measurement, it has been possible in the present work to study oxygen uptake of mitotically synchronized populations of Chinese hamster ovary (CHO) cells. MATERIALS AND METHODSCell Lines. CHO cells maintained in monolayer culture from frozen stocks for several years in this laboratory were used because they are well characterized. The procedures for culturing CHO cells, either in monolayer or in suspension, and for synchronization have been described (11). The mitotic index ofcells in mitosis was about 97% and did not change appreciably during the ESR measurement.ESR Closed-Chamber Method. A mixture of 10 ml of phosphate-buffered saline (Oxoid; Dulbecco's solution A without Mg2+ and Ca2+, pH 7.4) containing 0.114 mM spin probe [3-carbamoyl-2,2,5,5-tetramethyl-3-pyrroline-1-yloxy (CTPO); Aldrich] and 0.2% methyl cellulose E4M (Dow) or 0.1% agar (buffer A) was equilibrated with air at 370C with stirring for at least 10 min prior to use. About 5-10 X...

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“…However, starvation of cells leads to an increase in the fraction of mobile surface components. Furthermore, there are indications that, as in other cell systems [4,5], variations in the lateral diffusion occur during the cell cycle. Antibodies to surface components of T. thermophila were prepared by immunising rabbits subscapularly with an emulsion of pellicles (prepared according to [6]) in complete Freunds adjuvant.…”

Section: Introductionmentioning

confidence: 94%

Restricted lateral diffusion of surface membrane components in Tetrahymena thermophila

Hill

1981

FEBS Letters

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Electron spin resonance studies of changes in membrane fluidity of Chinese hamster ovary cells during the cell cycle

Cited by 50 publications

References 22 publications

Internalization of the dengue virus is cell cycle modulated in HepG2, but not vero cells

Internalization of the dengue virus is cell cycle modulated in HepG2, but not vero cells

ESR studies of O2 uptake by Chinese hamster ovary cells during the cell cycle.

Restricted lateral diffusion of surface membrane components in Tetrahymena thermophila

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