Equilibrium Dialysis of Ions in Nystatin-treated Red Cells

Cass, Albert; Dalmark, Mads

doi:10.1038/newbio244047a0

Cited by 194 publications

(156 citation statements)

References 12 publications

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“…The association of amphotericin B with both animal cells (Cass & Dalmark, 1973;Kumar et al, 1974) and mycoplasma cell membrane (D. B. Archer, University of Cambridge, personal communication) is reversible, and so we investigated the possibility that the binding of AME to protoplast membranes was also reversible. A suspension of protoplasts was incubated with AME at its m.i.c.…”

Section: I22 D Kerridge T Y Koh a N D A M Johnsonmentioning

confidence: 99%

“…It is assumed that the antibiotic interacts with the plasma membrane rendering it permeable to ions, but the presence of K + and Mg2 + ions in the suspending medium results in maintenance of the internal concentration required for growth. Polyene antibiotics have been used to affect reversibly the permeability of the plasma membrane of certain animal cells to both ions (Cass & Dalmark, 1973) and DNA (Kumar et al, 1974). In these systems the antibiotic was removed simply by washing the cell suspension with the incubation medium.…”

Section: Introductionmentioning

confidence: 99%

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The Interaction of Amphotericin B Methyl Ester with Protoplasts of Candida albicans

Kerridge

Koh

Johnson

1976

Journal of General Microbiology

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The interaction of amphotericin B methyl ester (AME) with protoplasts of Candida albicans was measured indirectly by following the incorporation of [U-l*C]phenylalanine into the acid-insoluble material. The inhibitory effects of AME at the minimum inhibitory concentration were prevented by the addition of 85 mM-KC1 and 45 mM-MgCl,, as shown by Liras & Lampen (1974) for Saccharomyces cerevisiae. In C. albicans, pretreatment of the yeast before antibiotic addition was unnecessary. KCl and MgCl, did not prevent AME from binding to the protoplast membrane. This interaction was reversed by incubating the protoplasts in the presence of the protecting salts.

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Section: I22 D Kerridge T Y Koh a N D A M Johnsonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Interaction of Amphotericin B Methyl Ester with Protoplasts of Candida albicans

Kerridge

Koh

Johnson

1976

Journal of General Microbiology

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“…Nai and Ki of unfractionated or fractionated red cells were each adjusted to ~ 50 mmol/liter cells by using a modification of the nystatin procedure (Cass and Dalmark, 1973) to be able to evaluate all transport parameters at their respective maximal values. At these concentrations of Nai and Ki, the Na/K pump is saturated (Post and Jolly, 1957) and the cotransport activity is also essentially maximal under these circumstances (Garay et al, 1981;Canessa et al, 1986;Kracke et al, 1988).…”

Section: Modifications Of Na and Kmentioning

confidence: 99%

Internal magnesium, 2,3-diphosphoglycerate, and the regulation of the steady-state volume of human red blood cells by the Na/K/2Cl cotransport system.

Mairbäurl

Hoffman

1992

The Journal of General Physiology

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This study is concerned with the relationship between the Na/K/CI cotransport system and the steady-state volume (MCV) of red blood cells. Cotransport rate was determined in unfractionated and density-separated red cells of different MCV from different donors to see whether cotransport differences contribute to the difference in the distribution of MCVs. Cotransport, studied in cells at their original MCVs, was determined as the bumetanide (10 ~.M)-sensitive 2~Na efflux in the presence of ouabain (50 I~M) after adjusting cellular Na (Nai) and K~ to achieve near maximal transport rates. This condition was chosen to rule out MCV-related differences in Nai and Ki that might contribute to differences in the net chemical driving force for cotransport. We found that in both unfractionated and density-separated red cells the cotransport rate was inversely correlated with MCV. MCV was correlated directly with red cell 2,3-diphosphoglycerate (DPG), whereas total red cell Mg was only slightly elevated in cells with high MCV. Thus intraceUular free Mg (Mg~ e) is evidently lower in red cells with high 2,3-DPG (i.e., high MCV) and vice versa. Results from flux measurements at their original MCVs, after altering Mg[ r~ with the ionophore A23187, indicated a high Mgi sensitivity of cotransport: depletion of M~ r~ inhibited and an elevation of M~ tee increased the cotransport rate. The apparent K05 for Mg~ e" was ~ 0.4 mM. Maximizing Mig~ ~ at optimum Nai and I~ minimized the differences in cotransport rates among the different donors. It is concluded that the relative cotransport rate is regulated for cells in the steady state at their original cell volume, not by the number of copies of the cotransporter but by differences in Mig~ ~. The interindividual differences in Mg~ ~, determined primarily by differences in the 2,3-DPG content, are responsible for the differences in the relative cotransport activity that results in an inverse Address reprint requests to Dr.

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“…26 The erythrocytes, washed as above in WS, were suspended at approximately 2% hematocrit in a sodium-loading solution (SLS) consisting of (mM) 75 NaCl, 75 KC1, 32 sucrose, 5 Hepes, 1 EGTA pH 7.4 at 4° C. Nystatin (Sigma Chemical Company, St. Louis, Missouri), dissolved in methanol just prior to each assay, was added to a final concentration of 30 /Ag/ml. The suspension was gently stirred for 20 minutes, then transferred to plastic centrifuge tubes at room temperature, centrifuged at 1000 g for 5 minutes, the supernatant discarded, and the cells washed twice with room temperature SLS to which 0.5% bovine albumin was added.…”

Section: Furosemide-sensitive Sodium-potassium Cotransportmentioning

confidence: 99%

Racial differences in erythrocyte cation transport.

Weder¹,

Torretti²,

Julius³

1984

Hypertension

101

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SUMMARY Erythrocyte contents and ouabain-insensitive transport pathways were measured hi 120 white and black normotensives and hypertensives. Mean maximal sodium-stimulated lithiumsodium countertransport rate was higher in white hypertensives than in white normotensives, and countertransport was significantly positively correlated with mean arterial pressure in whites. Values similar to those in white normotensives were found in both black normotensives and hypertensives, and countertransport was not significantly correlated with blood pressure in blacks. The rate constant for passive lithium efflux was greater in whites as compared to blacks, and the difference was not related to blood pressure level or sex. Ouabain-insensitive, furosemide-sensitive sodium and potassium effluxes were not found to be altered in hypertension. Furosemide-sensitive sodium efflux rate was lower in blacks but furosemide-sensitive potassium efflux was not similarly depressed. While white subjects demonstrated a close correlation between sodium and potassium effluxes, blacks did not. Further study of these differences in the cellular metabolism of sodium and potassium may provide clues to the pathogenesis of racial dissimilarities in total body sodium handling. (Hypertension 6: 115-123, 1984) KEY WORDS • race • countertransport • cotransport • erythrocyte E RYTHROCYTE lithium-sodium countertransport and sodium-potassium cotransport have been proposed as markers for human essential hypertension. 1 2 Virtually all reports have included only white subjects. For lithium-sodium countertransport, Canessa and colleagues' 3 have consistently demonstrated enhanced maximal activity in white hypertensives and others 4 "* have confirmed the observation, although agreement is not universal. 9 Canessa et al.'°r eported that black hypertensives had values similar to those of black normotensives. Etkin et al." observed increases in tracer sodium influx rates in the erythrocytes of white essential hypertensives but not in blacks and suggested that tracer influx rate is closely correlated with the acitivity of the lithium-sodium countertransport system. 12 However, Trevisan et al. 13 found a significant correlation between lithium-sodium countertransport and blood pressure in black schoolchildren, and Woods et al. l4 found higher countertransport rates in blacks by comparing the normotensive sons of two hypertensive parents and the normotensive sons of normotensive parents.

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Equilibrium Dialysis of Ions in Nystatin-treated Red Cells

Cited by 194 publications

References 12 publications

The Interaction of Amphotericin B Methyl Ester with Protoplasts of Candida albicans

The Interaction of Amphotericin B Methyl Ester with Protoplasts of Candida albicans

Internal magnesium, 2,3-diphosphoglycerate, and the regulation of the steady-state volume of human red blood cells by the Na/K/2Cl cotransport system.

Racial differences in erythrocyte cation transport.

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