Fatty acid chain flexibility in the membranes of normal and transformed fibroblasts.

Gaffney, Betty J.

doi:10.1073/pnas.72.2.664

Cited by 97 publications

(47 citation statements)

References 30 publications

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“…Von Dreele and Williams (19) recently reported the absence of change in membrane fluidity during the development of D. discoideum, using 16-nitroxide stearic acid spin labels which detected the isotropic motion of the lipids at a given temperature. The lack of any difference in membrane fluidity is also in accord with results from normal and transformed mouse 3T3 cells (5).…”

Section: Discussionsupporting

confidence: 73%

Spin-labeling studies on the Membranes of Differentiating Cells of <I>Dictyostelium discoideum</I>

Kawai¹,

Tanaka

1978

Cell Struct. Funct.

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ABSTRACT. Differentiating cells of Dictyostelium discoideum were spinlabeled with 5-nitroxide stearic acid or phosphatidylcholine spin labels, and the electron spin resonance spectra of the cells were measured. There was no difference in the flexibility of the lipid bilayer in the membranes between preaggregation cells and disaggregated slug cells. The temperature dependence of the overall splitting value for 5-nitroxide stearic acid was also indistinguishable for the two cell types in the range of 4°C to 25°C. Two distinct inflection points were observed at 15°C and 19.5°C in the temperature dependence, suggesting the presence of a phase transition in the lipid bilayer portion of the membranes. We thus concluded that there is no change in the membrane fluidity of the cells on formation of a multicellular organization. In addition, trypsinization of slug cells, which enhances Con A-induced redistribution of the Con A-binding sites on the cell surface (Kawai, in preparation), did not cause any change in the flexibility of the lipid bilayer. This suggests that the increased mobility of the sites has no apparent correlation to the bulk membrane fluidity.The lateral mobility of such receptor sites as the antigen and lectin binding sites intercalated in the plasma membranes has been considered to be under the control of the fluid state of the lipid bilayer of the membranes (13). On this basis, it has been widely supposed that the difference in the lateral mobility of the sites in the cell surface between normal and tumor or transformed cells is due to possible changes in membrane fluidity (4, 7, 11). Thus, we conducted, spin-labeling studies to examine whether there is any difference in the fluidity of the lipid bilayer of the membranes (5, 23) of these cells.In the development of the cellular slime mold Dictyosteliurn discoideum, amebae grow and multiply during the vegetative phase by feeding on bacteria. After the cessation of cell growth, amebae aggregate at a collecting point and form a slug-shaped cell mass. The slug undergoes a series of morphogenetic movements and finally produces a fruiting body consisting of spores and stalk cells. Several changes in the properties of the cell surface have been found during cell differentiation (1,20,22). By examining changes in the reactivity of differentiating cells with concanavalin A(Con A), a lectin which binds to the carbohydrate containing ligands on the cell surface (12), we found that Con A-induced agglutinability of the cells decreased as cells differentiate, especially upon the formation of a multicellular organization (9). We also found that the mobility of Con A-binding sites in the cell surface remarkably decreased during this process (Kawai and Takeuchi, in preparation ABSTRACT. Differentiating cells of Dictyostelium discoideum were spinlabeled with 5-nitroxide stearic acid or phosphatidylcholine spin labels, and the electron spin resonance spectra of the cells were measured. There was no difference in the flexibility of the lipid bilayer in the membranes betw...

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Section: Discussionsupporting

confidence: 73%

Spin-labeling studies on the Membranes of Differentiating Cells of <I>Dictyostelium discoideum</I>

Kawai¹,

Tanaka

1978

Cell Struct. Funct.

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“…PC (5,10) in the Light and Dark. Attempts to incorporate PC(5, 10) into oat leaf protoplasts were successful (Fig.…”

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confidence: 99%

“…Me-I5,10), 2-(l -carboxydecyl)-2-hexyl-4,4-dimethyl-3-oxazolidinyloxyl methyl ester; maleimide probe, 4-maleimido-2,2,6,6-tetramethylpiperidinooxyl; iodoacetamide probe, 4-(2-iodoacetamide)-2,2,6,6-tetramethylpiperidinooxyl; TEMPO, 2,2,6,6-tetramethylpiperidinooxyl; TEMPAMINE, 2,2,6,6-tetramethyl-4-aminopiperidinooxyl; cholestane probe, 4',4'-dimethylspiro [5a-cholestane-3,2'-oxazolidinJ-3'-yloxyl; androstane probe, 17,8-hydroxy -4',4' -dimethylspiro[5a-androstane-3,2' -oxazolidin]-3' -yloxyl; 2N8, 2-methyl-2-hexyl-4,4-dimethyl-3-oxazolidinyloxyl; 5N10, 2-n-butyl-2-n-pentyl-4,4-dimethyl-3-oxazolidinyloxyl; PC (5,10) Figure 5 and settings for I (1,14), Me-1(5,10), 5N10, and the androstane and cholestane probes were as in Figure 1. The sample temperature was controlled by a Varian variable temperature controller and was monitored by an Omega model 250 thermocouple positioned within the cuvette.…”

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confidence: 99%

Localization of Spin Labels in Oat Leaf Protoplasts

Briggs

Haug²,

Scheffer³

1982

Plant Physiol.

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An assay based on light-mediated oxidation was used to determine whether specific spin labels were partitioned throughout the protoplast or retained in the plasmalemma of Avena sativa L. cv. Garry and Park. Many classes of spin label were tested, including phospholipids, fatty acid, fatty acid methyl ester, maleimide, iodoacetamide, short chain hydrocarbon, androstane, 2,2,6,6-tetramethyl-4-aminopiperidinooxyl (TEMPAMINE) and 2,2,6,6-tetramethylpiperdinooxyl (TEMPO). All except the phosphotidylcholine spin label were found to partition throughout the cell. The phosphotidylcholine spin label may have been selectdvely retained in the plasmalemma.Changes in the plasma membranes of higher plants have been proposed as the basis of many cellular phenomena. Examples are development of cold tolerance, salt tolerance, and senescence. Also, changes in membrane structure may result from exposure to hormones, pathogens, radiation, and pressure. Usually, membrane structure has been studied with fixed tissues or with isolated membranes, precluding direct measurement of membrane changes in living cells.Spin labels have been used to study the plasma membrane of living cells. However, to selectively probe the plasmalemma of an intact protoplast, the probe must be reporting only from the plasmalemma. This condition can be met if the probe is only present in the plasmalemma or is spectroscopically inactive everywhere except in the plasmalemma. Kaplan et al. (14) claimed that by adding K3Fe(CN)6 (a spin label-activating agent) to a labeled cell suspension, only the spin-label in the plasma membrane gave an ESR signal. The assumptions that spin labels cannot move quickly between membranes and that different membranes would create different spin label spectra are also used to support the contention that fatty acid spin labels are good probes for the plasma membrane (2-4, 7, 10, 13, 24, 25). However, some investigators dispute these assumptions (12, 16), arguing that most spin labels report an average from every membrane in the cell.The objectives of this report were to: (a) evaluate whether or not fatty acid spin labels are selective for the plasmalemma of plant protoplasts; (b) develop criteria for ascertaining the selectivity of a spin label for the plasmalemma; and (c) test various classes of spin label and identify those which may have selectivity for the plasmalemma. MATERIALS AND METHODSAvena sativa L. cv. Garry and Park were grown in the laboratory at 22°C in vermiculite irrigated with White's nutrient solution (8). Fluorescent and incandescent bulbs provided a 16-h photoperiod. Primary leaves were harvested from 1-to 2-week-old seedlings.Protoplasts were isolated by peeling away the lower epidermis of the leaves with forceps and floating the leaves (peeled surface down) on a solution composed 6f 0.5% Cellulysin (CalbiochemBehring Corp.) and 0.6 M sorbitol, adjusted to pH 5.6 with KOH. The preparation was incubated at 28°C for 3 h in the light, then was swirled gently to release protoplasts. The protoplasts were fi...

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“…This alteration in the average number of fatty acid double bonds in the lipids derived from erythrocytes of normal and CHS mice or humans can account for the observed differences in membrane fluidity . Gaffney (19) has shown that a 10% increase in the number of unsaturated fatty acid chains can result in a significant change in membrane fluidity. Her studies were carried out in a model bilayer system of synthetic dioleoyl and diarachidonoyl lecithins.…”

Section: Discussionmentioning

confidence: 99%

Fluidity properties and liquid composition of erythrocyte membranes in Chediak-Higashi syndrome.

Ingraham

Burns

Boxer

et al. 1981

The Journal of Cell Biology

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We have earlier shown through electron spin resonance (ESR) studies of leukocytes that membranes of cells from both Chediak-Higashi syndrome (CHS) mice and humans have abnormally high fluidity . We have extended our studies to erythrocytes . Erythrocytes were labeled with the nitroxide-substituted analogue of stearic acid, 2-(3-carboxypropyl)-4,4-dimethyl-2-tridecyl-3-oxazolidinyloxyl, and ESR spectra were obtained . Order parameter, S, at 23°C, was 0.661 and 0.653 for erythrocytes of normal and CHS mice (P < 0.001) . S was 0.684 for normal human erythrocytes and 0.675 (P < 0.001) for CHS erythrocytes at 25°C. Because S varies inversely to fluidity, these results indicate that CHS erythrocytes tend to have higher fluidity than normal . In vitro treatment of both mice and human CHS erythrocytes with 10 mM ascorbate returned their membrane fluidity to normal . We prepared erythrocyte ghosts and extracted them with CHC1 3:CH3OH (2 :1) . Gas-liquid chromatography analysis showed a greater number of unsaturated fatty acids for CHS . The average number of double bonds detected in fatty acids for mice on a standard diet was 1 .77 for normal and 2.02 for CHS (P < 0.04) ; comparison of human erythrocytes from one normal control and one CHS patient showed a similar trend . Our results suggest that an increased proportion of unsaturated fatty acids may contribute to increased fluidity of CHS erythrocytes . Our observation that both leukocytes and erythrocytes of CHS have abnormal fluidity indicates that CHS pathophysiology may relate to a general membrane disorder.

show abstract

Fatty acid chain flexibility in the membranes of normal and transformed fibroblasts.

Abstract: Fatty acid spin labels were used to measure the inherent flexibility of the lipid acyl chains in intact

Cited by 97 publications

References 30 publications

Spin-labeling studies on the Membranes of Differentiating Cells of <I>Dictyostelium discoideum</I>

Spin-labeling studies on the Membranes of Differentiating Cells of <I>Dictyostelium discoideum</I>

Localization of Spin Labels in Oat Leaf Protoplasts

Fluidity properties and liquid composition of erythrocyte membranes in Chediak-Higashi syndrome.

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