The Intake of Radioactive Isotopes by Living Cells

Brooks, S. C.

doi:10.1101/sqb.1940.008.01.018

Cited by 37 publications

(9 citation statements)

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“…Hoagland and Broyer (1942) confirmed the rapid movement of ions from the medium into the protoplasm of Nitella and its slow transference into the sap. In contrast to Brooks, they found that when the experimental period was prolonged, the apparent con- M sodium chloride labelled with radioactive sodium, and 0-01 M sodium bromide labelled with radioactive bromide for 24 hr (redrawn from Brooks, 1940); b. Relationship between the apparent free space of bean root tissue and the external concentration of potassium chloride.…”

Section: Early Observationsmentioning

confidence: 87%

Mineral salts absorption in plants

Sutcliffe¹

1962

133

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Section: Early Observationsmentioning

confidence: 87%

Mineral salts absorption in plants

Sutcliffe¹

1962

133

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“…Only these latter will be mentioned here. Brooks (1940Brooks ( , 1951, whose experiments were few in number and not altogether satisfactory, found that radioactive sodium and potassium entered the protoplasm of Nitella more readily than they crossed the tonoplast into the vacuole and that after 6 hours there was no measurable penetration into the sap. Hoagland and Broyer (1942) measured the rate of penetration of rubidium into Nitella and also concluded that the tonoplast was the main barrier to ions.…”

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confidence: 99%

Ion Transport in Nitellopsis Obtusa

Macrobbie

Dainty

1958

The Journal of General Physiology

171

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The distribution and rates of exchange of the ions sodium, potassium, and chloride in single internodal cells of the ecorticate characean, Nitdlopsis obtusa, have been studied.In tracer experiments three kinetic compartments were found, the outermost "free space" of the cell, a compartment we have called "protoplasmic non4ree space", and the cell sap.The concentrations in the vacuole were 54 m~ Na +, 113 mM K +, and 206 m~ C1-. The steady state fluxes across the vacuolar membrane were 0.4 pmole Na+/cm. ~ sec., 0.25 pmole K+/cm. s sec., and 0.5 pmole C1-/cm? sec.The protoplasmic Na/K ratio is equal to that in the vacuole but protoplasmic chloride is relatively much lower. Osmotic considerations suggest a layer 4 to 6 # thick with sodium and potassium concentrations close to those in the vacuole. The fluxes between protoplasm and external solution were of the order of 8 pmoles Na+/ cm. ~ sec. and 4 pmoles K+/cm. 2 sec.We suggest that the protoplasm is separated from the cell wall by an outer protoplasmic membrane at which an outward sodium transport maintains the high K/Na ratio of the cell interior, and from the vacuole by the tonoplast at which an inward chloride transport maintains the high vacuolar chloride. The tonoplast appears to be the site of the principal diffusion resistance of the cell, but the outer protoplasmic membrane probably of the main part of the potential. I N T R O D U C T I O NThere are practically no studies on the ion permeability of plant ceils and tissues which are comparable--in the details elucidated--with those made by animal physiologists on nerve, muscle, and erythrocytes. The plant cell with its cell wall, large central vacuole, and thin layer of protoplasm is sufficiently complicated to make such a study difficult but in the plant physiologists' favourite material--roots, storage tissue, etc.--these difficulties are added to by morphological complications. It has thus been possible less often in plant systems to express the results of an experiment in fully quantitative terms--as an ion flux in pmoles (10 -12 moles) per sq. cm. per second across a well defined morphological boundary separating two phases in which the electrochemical activities of the ion are known. This is the general aim of our work. 335

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“…These two elements have qualitatively similar effects on the contraction of the isolated heart (2), on the depolarization of nerve or muscle preparations (3,4), and on the activity of certain intracellular enzyme systems (5,6). The distribution of rubidium in human tissues resembles that of potassium (1,7), and rubidium has been shown to be concentrated in certain plant cells (8) and in animal tissues (9, 10) with great rapidity. It has also been reported that addition of rubidium to a potassium-free diet will prevent the development in rats of most of the histological changes agsociated with potassium depletion (1).…”

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The Acidifying Effect of Rubidium in Normal and Potassium-Deficient Alkalotic Rats 1

Relman¹,

Roy²,

Schwartz³

1955

J. Clin. Invest.

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Rubidium, element number 37, is an alkalimetal found in small quantities in the earth's crust, and in trace amounts in human tissues (1). Listed immediately below potassium in the Group I elements of the periodic table, rubidium possesses many of potassium's physical, chemical, and physiological properties. These two elements have qualitatively similar effects on the contraction of the isolated heart (2), on the depolarization of nerve or muscle preparations (3,4), and on the activity of certain intracellular enzyme systems (5, 6). The distribution of rubidium in human tissues resembles that of potassium (1, 7), and rubidium has been shown to be concentrated in certain plant cells (8) and in animal tissues (9, 10) with great rapidity. It has also been reported that addition of rubidium to a potassium-free diet will prevent the development in rats of most of the histological changes agsociated with potassium depletion (1).The central purpose of the present work was to compare the effects of rubidium aidd potassium ions on acid-base balance in normal and in potassium-depleted rats. When given an alkaline-ash, potassium-deficient diet, rats develop an alkalosis (12), which can be rapidly corrected by administration of potassium chloride (13)

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The Intake of Radioactive Isotopes by Living Cells

Cited by 37 publications

References 0 publications

Mineral salts absorption in plants

Mineral salts absorption in plants

Ion Transport in Nitellopsis Obtusa

The Acidifying Effect of Rubidium in Normal and Potassium-Deficient Alkalotic Rats 1

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