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1.
Paul Reznikoff 《The Journal of general physiology》1928,11(3):221-232
I. The Plasmalemma. 1. On the plasmalemma of amebæ CaCl2 antagonizes the toxic action of LiCl better than it does NaCl, and still better than it does KCl. MgCl2 antagonizes the toxic action of NaCl better than it does LiCl and still better than it does KCl. 2. CaCl2 antagonizes the toxic action of LiCl and of KCl better than does MgCl2: MgCl2 antagonizes NaCl better than does CaCl2. II. The Internal Protoplasm. 3. The antagonizing efficiency of CaCl2 and of MgCl2 are highest against the toxic action of KCl on the internal protoplasm, less against that of NaCl, and least against that of LiCl. 4. CaCl2 antagonizes the toxic action of LiCl better than does MgCl2: MgCl2 antagonizes the toxic action of NaCl and of KCl better than does CaCl2. 5. LiCl antagonizes the toxic action of MgCl2 on the internal protoplasm more effectively than do NaCl or KCl, which have an equal antagonizing effect on the MgCl2 action. III. The Nature of Antagonism. 6. When the concentration of an antagonizing salt is increased to a toxic value, it acts synergistically with a toxic salt. 7. No case was found in which a potentially antagonistic salt abolishes the toxic action of a salt unless it is present at the site (surface or interior) of toxic action. 8. Antagonistic actions of the salts used in these experiments are of differing effectiveness on the internal protoplasm and on the surface membrane. 相似文献
2.
W. J. V. Osterhout 《The Journal of general physiology》1921,3(4):415-429
1. The equations which serve to predict the injury of tissue in 0.52 M NaCl and in 0.278 M CaCl2 and its subsequent recovery (when it is replaced in sea water) also enable us to predict the behavior of tissue in mixtures of these solutions, as well as its recovery in sea water after exposure to mixtures. 2. The reactions which are assumed in order to account for the behavior of the tissue proceed as if they were inhibited by a salt compound formed by the union of NaCl and CaCl2 with some constituent of the protoplasm (certain of these reactions are accelerated by CaCl2). 3. In this and preceding papers a quantitative theory is developed in order to explain: (a) the toxicity of NaCl and CaCl2; (b) the antagonism between these substances; (c) the fact that recovery (in sea water) may be partial or complete, depending on the length of exposure to the toxic solution. 相似文献
3.
1. Permeability to water in unfertilized eggs of the sea urchin, Arbacia punctulata, is found to be greater in hypotonic solutions of dextrose, saccharose and glycocoll than in sea water of the same osmotic pressure. 2. The addition to dextrose solution of small amounts of CaCl2 or MgCl2 restores the permeability approximately to the value obtained in sea water. 3. This effect of CaCl2 and MgCl2 is antagonized by the further addition of NaCl or KCl. 4. It is concluded that the NaCl and KCl tend to increase the permeability of the cell to water, CaCl2 and MgCl2 to decrease it. 5. The method here employed can be used for quantitative study of salt antagonism. 相似文献
4.
In Nitella the substitution of KCl for NaCl changes the P.D. in a negative direction. In some cases this change is lessened by adding solid CaCl2 to the solution of KCl. This may be due to lessening the partition coefficient of KCl or to decreasing the solubility of an organic substance which sensitizes the cell to the action of KCl. Little or no correlation exists between this effect of calcium and its ordinary antagonistic action in producing a balanced solution which preserves the life of the cell indefinitely. CaCl2 is negative to NaCl but positive to KCl. The effects of mixtures of KCl, NaCl, and CaCl2 are discussed. The concentration effect of a mixture of KCl + CaCl2 shows certain peculiarities due to action currents: these resemble those found with pure KCl. These studies and others on Nitella, Valonia, and Halicystis indicate that mobilities and partition coefficients are variable and can be brought under experimental control. 相似文献
5.
L. R. Blinks 《The Journal of general physiology》1929,13(2):223-229
The cells of Halicystis impaled on capillaries reach a steady P.D. of 60 to 80 millivolts across the protoplasm from sap to sea water. The outer surface of the protoplasm is positive in the electrometer to the inner surface. The P.D. is reduced by contact with sap and balanced NaCl-CaCl2 mixtures; it is abolished completely in solutions of NaCl, CaCl2, KCl, MgSO4, and MgCl2. There is prompt recovery of P.D. in sea water after these exposures. 相似文献
6.
By means of micro-dissection and injection Amœba proteus was treated with the chlorides of Na, K, Ca, and Mg alone, in combination, and with variations of pH. I. The Plasmalemma. 1. NaCl weakens and disrupts the surface membrane of the ameba. Tearing the membrane accelerates the disruption which spreads rapidly from the site of the tear. KCl has no disruptive effect on the membrane but renders it adhesive. 2. MgCl2 and CaCl2 have no appreciable effect on the integrity of the surface membrane of the ameba when applied on the outside. No spread of disruption occurs when the membrane is torn in these salts. When these salts are introduced into the ameba they render the pellicle of the involved region rigid. II. The Internal Protoplasm. 3. Injected water either diffuses through the protoplasm or becomes localized in a hyaline blister. Large amounts when rapidly injected produce a "rushing effect". 4. HCl at pH 1.8 solidifies the internal protoplasm and at pH 2.2 causes solidification only after several successive injections. The effect of the subsequent injections may be due to the neutralization of the cell-buffers by the first injection. 5. NaCl and KCl increase the fluidity of the internal protoplasm and induce quiescence. 6. CaCl2 and MgCl2 to a lesser extent solidify the internal protoplasm. With CaCl2 the solidification tends to be localized. With MgCl2 it tends to spread. The injection of CaCl2 accelerates movement in the regions not solidified whereas the injection of MgCl2 induces quiescence. III. Pinching-Off Reaction. 7. A hyaline blister produced by the injection of water may be pinched off. The pinched-off blister is a liquid sphere surrounded by a pellicle. 8. Pinching off always takes place with injections of HCl when the injected region is solidified. 9. The injection of CaCl2 usually results in the pinching off of the portion solidified. The rate of pinching off varies with the concentration of the salt. The injection of MgCl2 does not cause pinching off. IV. Reparability of Torn Surfaces. 10. The repair of a torn surface takes place readily in distilled water. In the different salt solutions, reparability varies specifically with each salt, with the concentration of the salt, and with the extent of the tear. In NaCl and in KCl repair occurs less readily than in water. In MgCl2 repair takes place with great difficulty. In CaCl2 a proper estimate of the process of repair is complicated by the pinching-off phenomenon. However, CaCl2 is the only salt found to increase the mobility of the plasmalemma, and this presumably enhances its reparability. 11. The repair of the surface is probably a function of the internal protoplasm and depends upon an interaction of the protoplasm with the surrounding medium. V. Permeability. 12. NaCl and KCl readily penetrate the ameba from the exterior. CaCl2 and MgCl2 do not. 13. All four salts when injected into an ameba readily diffuse through the internal protoplasm. In the case of CaCl2 the diffusion may be arrested by the pinching-off process. VI. Toxicity. 14. NaCl and KCl are more toxic to the exterior of the cell than to the interior, and the reverse is true for CaCl2 and MgCl2. 15. The relative non-toxicity of injected NaCl to the interior of the ameba is not necessarily due to its diffusion outward from the cell. 16. HCl is much more toxic to the exterior of a cell than to the interior; at pH 5.5 it is toxic to the surface whereas at pH 2.5 it is not toxic to the interior. NaOH to pH 9.8 is not toxic either to the surface or to the interior. VII. Antagonism. 17. The toxic effects of NaCl and of KCl on the exterior of the cell can be antagonized by CaCl2 and this antagonism occurs at the surface. Although the lethal effect of NaCl is thus antagonized, NaCl still penetrates but at a slower rate than if the ameba were immersed in a solution of this salt alone. 18. NaCl and HCl are mutually antagonistic in the interior of the ameba. No antagonism between the salts and HCl was found on the exterior of the ameba. No antagonism between the salts and NaOH was found on the interior or exterior of the ameba. 19. The pinching-off phenomenon can be antagonized by NaCl or by KCl, and the rate of the retardation of the pinching-off process varies with the concentration of the antagonizing salt. 20. The prevention of repair of a torn membrane by toxic solutions of NaCl or KCl can be antagonized by CaCl2. These experiments show directly the marked difference between the interior and the exterior of the cell in their behavior toward the chlorides of Na, K, Ca, and Mg. 相似文献
7.
Jacques Loeb 《The Journal of general physiology》1922,5(2):231-254
1. It is shown that NaCl acts like CaCl2 or LaCl3 in preventing the diffusion of strong acids through the membrane of the egg of Fundulus with this difference only that a M/8 solution of NaCl acts like a M/1,000 solution of CaCl2 and like a M/30,000 solution of LaCl3. 2. It is shown that these salts inhibit the diffusion of non-dissociated weak acid through the membrane of the Fundulus egg but slightly if at all. 3. Both NaCl and CaCl2 accelerate the diffusion of dissociated strong alkali through the egg membrane of Fundulus and CaCl2 is more efficient in this respect than NaCl. 4. It is shown that in moderate concentrations NaCl accelerates the rate of diffusion of KCl through the membrane of the egg of Fundulus while CaCl2 does not. 相似文献
8.
Extracts of the jelly coat of eggs of several marine invertebrates are known to induce in homologous sperm morphological changes known as the acrosome reaction. When sperm of the sea urchin Strongylocentrotus purpuratus are treated with low concentrations (0.2 μg fucose/ml) of egg jelly coat or 30 mM CaCl2 in artificial seawater the acrosome reaction does not occur. However, either of these treatments causes the exposure of an acrosin-like enzyme to exogenous substrate and inhibitors. Subsequent addition of jelly coat to 3.7 μg fucose/ml to sperm in this “initial stage” induces the acrosome reaction (as judged by the appearance of an acrosomal filament). This concentration is also effective for untreated sperm. If inhibitors of the enzyme (diisopropylphosphofluoridate or phenylmethanesulfonyl fluoride) are added to sperm in the initial stage, no acrosomal filaments are observed when the high concentration of jelly coat is added. Whether other morphological changes occur in these sperm has not been examined. If phenylmethanesulfonyl fluoride is added 4 sec after the jelly coat, the acrosomal filaments are observed, but the sperm still fail to fertilize eggs. These results suggest a dual role for the acrosin-like enzyme(s), first in the mechanism of the acrosomal filament formation and then in a subsequent event in the fertilization process. 相似文献
9.
S. C. Brooks 《The Journal of general physiology》1925,7(3):327-330
The electrical conductivity of the plasmodium of the slime-mold Brefeldia maxima (Fr.) Rost., which constitutes practically pure protoplasm, was found to be approximately equivalent under normal conditions to that of a 0.00145 N NaCl solution, and about 2.8 times that of the liquid in contact with which it developed. When bathed in 1 per cent sea water, the conductivity was much increased, becoming greater than that of the surrounding fluid. These preliminary tests are in agreement with the supposition that the protoplasm is permeable to and in equilibrium with its environment in so far as electrolytes are concerned. 相似文献
10.
A. M. Hamada 《Biologia Plantarum》1994,36(4):623-627
The lengths of roots and shoots, fresh and dry matter yield, and the contents of insoluble saccharides and free amino acids
were reduced with the rise in NaCl concentration. However, under combination of NaCl with Ca2+ ions, these parameters generally raised. Contents of soluble saccharides, proline and quaternary ammonium compounds increased
with increasing NaCl concentration, but under addition of CaCl2 or CaSO4, contents of these compounds were decreased. Low concentrations of NaCl stimulated soluble proteins, production, but higher
concentrations decreased the content of soluble proteins. Addition of Ca2+ in the media did not improve the soluble protein production. Insoluble proteins content was increased with the rise of salinity
level, but these effects were more pronounced with NaCl and CaCl2 or CaSO4 than with NaCl only. 相似文献
11.
Matilda Moldenhauer Brooks 《Protoplasma》1927,2(1):420-427
Summary The penetration of the dye, dahlia, into the sap ofNitella has been determined in the presence of NaCl, KCl, MgCl2 and CaCl2 at various concentrations.NaCl is the least effective and MgCl2 was the most effective in preventing penetration of the dye.It was found that NaCl antagonizes the action of CaCl2 in certain proportions to a small degree but not sufficiently to permit the dye to penetrate at a normal rate.Published by permission of the Surgeon General. 相似文献
12.
O. L. Inman 《The Journal of general physiology》1921,3(4):533-537
1. In highly hypertonic solutions of sea water the rate of respiration of Laminaria agardhii is rapidly reduced. 2. In highly hypotonic solutions the rate of respiration of Laminaria agardhii is reduced somewhat less rapidly than in the case of hypertonic solutions. 3. Hypertonic solutions of NaCl, CaCl2, and of mixtures of NaCl, and CaCl2 in the proportion of 50:1, all caused a decrease in the rate of respiration of wheat seedlings. 相似文献
13.
A reproducible and effective method for fertilization eggs of Xenopus laevis was developed based of systematic manipulation of environmental factors. The effects of varying concentrations of individual components of a fertilization medium were tested by measuring jelly swelling, sperm motility, and sperm longevity. Results were used to develop an improved medium for fertilization, consisting of 41.25 mM NaCl, 1.25 mM KCl, 0.25 mM CaCl2, 0.0625 mM MgCl2, 0.5 mM Na2HPO4, 2.5 mM HEPES, 1.9 mM NaOH, final pH(2°) 7.8. 相似文献
14.
Henry S. Simms 《The Journal of general physiology》1929,12(6):783-792
The pH of a 0.01 molar solution of glycine, half neutralized with NaOH, is 9.685. Addition of only one of the salts NaCl, KCl, MgCl2, or CaCl2 will lower the pH of the solution (at least up to 1 µ). If a given amount of KCl is added to a glycine solution, the subsequent addition of increasing amounts of NaCl will first raise the pH (up to 0.007 M NaCl). Further addition of NaCl (up to 0.035 M NaCl) will lower the pH, and further additions slightly raise the pH. The same type of curve is obtained by adding NaCl to glycine solution containing MgCl2 or CaCl2 except that the first and second breaks occur at 0.015 M and 0.085 M NaCl, respectively. Addition of CaCl2 to a glycine solution containing MgCl2 gives the same phenomena with breaks at 0.005 M and 0.025 M CaCl; or at ionic strengths of 0.015 µCaCl2 and 0.075 µCaCl2. This indicates that the effect is a function of the ionic strength of the added salt. These effects are sharp and unmistakable. They are almost identical with the effects produced by the same salt mixtures on the pH of gelatin solutions. They are very suggestive of physiological antagonisms, and at the same time cannot be attributed to colloidal phenomena. 相似文献
15.
1. The ions of Ca and K condition general luminescence, and are therefore necessary to the conduction of the impulse. 2. In van''t Hoff''s solution from which Mg is omitted, Berœ shows hyperirritability with respect to luminescence. This is the result of the action of Ca and K ions unantagonized by Mg. 3. The luminescent material spread on filter paper does not show luminescence in sea water, NaCl, MgCl2, or saccharose solutions isotonic with sea water. In solutions of CaCl2, SrCl2, BaCl2, KCl, and K2SO4 the indicator paper glows with a bright luminescence. 4. In dark adapted Berœ, luminescence is inhibited by a certain quantity of light. This quantity has an average value of 57,285 meter-candle-minutes, which is twelve times the value given by Mnemiopsis. 相似文献
16.
Influence of Electrolytes on the Thicknesses of the Phospholipid Bilayers of Lamellar Lecithin Mesophases 总被引:1,自引:0,他引:1
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Over a wide range of water contents, aqueous lecithin-water mixtures are mesophases in which lecithin bilayers alternate with water layers. This paper reports on low-angle X-ray diffraction measurements of the effects of electrolytes, at 1.0 N concentration, on the thicknesses of the bilayers in mesophases formed by the synthetic lecithin: 1-octadec-9-enyl-2-hexadecylglycerophosphocholine. With solutions of LiCl, NaCl, Na2SO4, KCl, and CsCl, the bilayer thicknesses are less than with pure water. The maximum reduction in bilayer thickness with these electrolytes is about 10% and occurs with mesophases of high content of KCl and CsCl solutions. With HCl solutions the bilayer thicknesses are about 5% greater than with pure water, and with CaCl2 solutions the bilayer thicknesses are about the same as with pure water. The maximum amount of solution which can be mixed with lecithin before a second, purely aqueous phase is formed is also affected by electrolytes, the order for the various 1.0 N solutions being CsCl = KCl > NaCl > Na2SO4 > (pure water) = LiCl > CaCl2. 相似文献
17.
Fertilized eggs of the mollusk Ilyanassa obsoleta (Nassarius obsoletus) form large blebs resembling polar lobes within 12 min of exposure to solutions of isotonic CaCl2, whereas control eggs in sea water remain spherical. Under identical conditions, fertilized eggs of the sea urchin, Strongylocentrotus purpuratus, an organism which normally does not form polar lobes, do not form blebs upon exposure to solutions of isotonic CaCl2. The calcium-induced blebbing in Ilyanassa still occurs if other cations such as Na+, Mg2+, or Mn2+ are present in addition to Ca2+, but not if comparable concentrations of K+ are present. Cytochalasin B prevents the calcium-induced blebbing, whereas colchicine does not. Cytokinesis in both Ilyanassa and Strongylocentrotus and normal polar lobe formation in Ilyanassa appear to require exogenous K+ but not exogenous Ca2+. Preliminary electron microscopy of Ilyanassa eggs exposed to isotonic solutions of CaCl2 has shown microfilaments in the cortical cytoplasm in the region of the bleb constriction but no microfilaments in spherical control eggs in sea water. These data suggest that high concentrations of exogenous Ca2+ trigger the polymerization and contraction of a ring of microfilaments in the cortical cytoplasm of the Ilyanassa egg which results in the formation of a lobelike bleb of cytoplasm. The observation that K+ antagonizes this Ca2+-induced blebbing has led to the formulation of a theory which postulates that the ratio of intracellular Ca2+ to intracellular K+ is critical in the control of polar lobe formation and cytokinesis. 相似文献
18.
19.
Marian Irwin 《The Journal of general physiology》1926,10(2):271-287
When living cells of Nitella are exposed to an acetate buffer solution until the pH value of the sap is decreased and subsequently placed in a solution of brilliant cresyl blue, the rate of penetration of dye into the vacuole is found to decrease in the majority of cases, and increase in other cases, as compared with the control cells which are transferred to the dye solution directly from tap water. This decrease in the rate is not due to the lowering of the pH value of the solution just outside the cell wall, as a result of diffusion of acetic acid from the cell when cells are removed from the buffer solution and placed in the dye solution, because the relative amount of decrease (as compared with the control) is the same whether the external solution is stirred or not. Such a decrease in the rate may be brought about without a change in the pH value of the sap if the cells are placed in the dye solution after exposure to a phosphate buffer solution in which the pH value of the sap remains normal. The rate of penetration of dye is then found to decrease. The extent of this decrease is the greater the lower the pH value of the solution. It is found that hydrochloric acid and boric acid have no effect while phosphoric acid has an inhibiting effect at pH 4.8 on stirring. Experiments with neutral salt solutions indicate that a direct effect on the cell (decreasing penetration) is due to monovalent base cations, while there is no such effect directly on the dye. It is assumed that the effect of the phosphate and acetate buffer solutions on the cell, decreasing the rate of penetration, is due (1) to the penetration of these acids into the protoplasm as undissociated molecules, which dissociate upon entrance and lower the pH value of the protoplasm or to their action on the surface of the protoplasm, (2) to the effect of base cations on the protoplasm (either at the surface or in the interior), and (3) possibly to the effect of certain anions. In this case the action of the buffer solution is not due to its hydrogen ions. In the case of living cells of Valonia under the same experimental conditions as Nitella it is found that the rate of penetration of dye decreases when the pH value of the sap increases in presence of NH3, and also when the pH value of the sap is decreased in the presence of acetic acid. Such a decrease may be brought about even when the cells are previously exposed to sea water containing HCl, in which the pH value of the sap remains normal. 相似文献
20.
OSTERHOUT WJ 《The Journal of general physiology》1956,39(6):963-976
The behavior of the cell depends to a large extent on the permeability of the outer non-aqueous surface layer of the protoplasm. This layer is immiscible with water but may be quite permeable to it. It seems possible that a reversible increase or decrease in permeability may be due to a corresponding increase or decrease in the water content of the non-aqueous surface layer. Irreversible increase in permeability need not be due primarily to increase in the water content of the surface layer but may be caused chiefly by changes in the protoplasm on which the surface layer rests. It may include desiccation, precipitation, and other alterations. An artificial cell is described in which the outer protoplasmic surface layer is represented by a layer of guaiacol on one side of which is a solution of KOH + KCl representing the external medium and on the other side is a solution of CO2 representing the protoplasm. The K+ unites with guaiacol and diffuses across to the artificial protoplasm where its concentration becomes higher than in the external solution. The guaiacol molecule thus acts as a carrier molecule which transports K+ from the external medium across the protoplasmic surface. The outer part of the protoplasm may contain relatively few potassium ions so that the outwardly directed potential at the outer protoplasmic surface may be small but the inner part of the protoplasm may contain more potassium ions. This may happen when potassium enters in combination with carrier molecules which do not completely dissociate until they reach the vacuole. Injury and recovery from injury may be studied by measuring the movements of water into and out of the cell. Metabolism by producing CO2 and other acids may lower the pH and cause local shrinkage of the protoplasm which may lead to protoplasmic motion. Antagonism between Na+ and Ca++ appears to be due to the fact that in solutions of NaCl the surface layer takes up an excessive amount of water and this may be prevented by the addition of suitable amounts of CaCl2. In Nitella the outer non-aqueous surface layer may be rendered irreversibly permeable by sharply bending the cell without permanent damage to the inner non-aqueous surface layer surrounding the vacuole. The formation of contractile vacuoles may be imitated in non-living systems. An extract of the sperm of the marine worm Nereis which contains a highly surface-active substance can cause the egg to divide. It seems possible that this substance may affect the surface layer of the egg and cause it to take up water. A surface-active substance has been found in all the seminal fluids examined including those of trout, rooster, bull, and man. Duponol which is highly surface-active causes the protoplasm of Spirogyra to take up water and finally dissolve but it can be restored to the gel state by treatment with Lugol solution (KI + I). The transition from gel to sol and back again can be repeated many times in succession. The behavior of water in the surface layer of the protoplasm presents important problems which deserve careful examination. 相似文献