Isotonic NaCl Solution Research Articles

The fertilization and development of the sea urchin egg, Arbacia lixula, under the influence of fractions of egg homogenate

Unfertilized eggs of Arbacia lixula were homogenized in the presence of isotonic NaCl solution. The microscopic granules were spun down by centrifugation for 30 minutes at 8 000 g. The granular fraction was dissolved in distilled water and dialyzed against sea water. The supernatant was also dialyzed against sea water. Before being tested both the extract from the granular fraction (I) and the supernatant (II) have been diluted with sea water, usually 1:10. I contains a membrane elevating factor, MbElF(E); II contains antifertilizin or according to the terminology adopted above the jelly precipitating factor, JePptF(E). (E) indicates that the factors are obtained from the eggs. Upon insemination of the Arbacia eggs in normal sea water the eggs are fertilized but in most batches of eggs the membrane adheres closely to the egg surface and has not the optical properties of the normal membrane. In the presence of MbElF(E) a membrane elevation occurs. The membrane becomes more refractile and more solidified. The retardation is higher than in the adherent membranes. Heating of the extract from the granular fraction to 45 ° or 60 °C for 30 minutes decreases or abolishes the MbElF-effect. Eggs with jelly precipitated under the action of JePptF(E) can be fertilized and they exhibit an elevated refractile fertilization membrane. Even the heated II has this effect, although no precipitation of the jelly coat occurs. In eggs deprived of their jelly coats an adherent membrane is formed upon fertilization in the presence of II. JePptF thus causes no elevation of the membrane in absence of the jelly coat. Some kind of interaction between JePptF and the jelly coat is thus necessary to induce the membrane elevation. If jellyless fertilized eggs remain in contact with II a sort of tanning of the membrane occurs which remains adherent to egg surface. This observation speaks in favour of the presence of a membrane toughening factor in II. MbElF(E) favours the membrane elevation also when unfertilized eggs are subjected to a hypertonic solution. In certain experiments the homogenization was carried out in a mixture of NaCl and CaCl 2 (concentrations as in sea water). It was evident from the results that in the presence of calcium MbElF(E) is partly released from the granules. After previous homogenization in the presence of Ca the MbElF-action is thus also found in II. Under a certain season the control almost invariably gave radially symmetrical or slightly animalized larvae. This tendency was counteracted when the eggs were fertilized in and reared 5–6 hours after fertilization in sea water containing extract from the granular fraction. Like MbElF(E) the anti-radialization factor was inactivated by warming to 45 ° or 60 °C for 30 minutes. These results suggest that a release of substances from the microscopic granules in the egg may play a role for the balance between ventral and dorsal tendencies in the early sea urchin development.

XIX.—The Effect of the Inhibition of Respiration and Assimilation on the DiatomDitylum Brightwelli(West)

Ditylum Brightwelli, a marine plankton diatom, shows very peculiar osmotic relations which have recently been investigated by Gross (1939). The cells (fig. 1) consist of a central mass of protoplasm containing the nucleus and connected by a few protoplasmic strands with the peripheral plasma membrane in which are embedded numerous chromatophores. The remainder of the space inside the cell is filled with cell sap. As in other diatoms, the protoplast is enclosed by a siliceous cell wall. Gross found thatDitylumplasmolyses rapidly in isotonic and hypotonic NaCl and sugar solutions, being reduced in a few seconds to a small spherical body about one-third to one-twentieth of its original volume, similar in all respects to a resting spore. In a solution of NaCl + CaCl2, and in unbuffered artificial sea-water, plasmolysis occurs in all cells, but the process is considerably delayed and completed only after several hours. In artificial sea-water, the pH of which is adjusted to about 8, the cells remain unchanged.

THE ACTION OF MAGNESIUM SULPHATE ON THE INTESTINE OF THE CAT

1. Isotonic MgSO4 slows the absorption of isotonic NaCl solutions in the intestine of the cat. It does not influence the absorption of glucose solutions. It does delay slightly the absorption of distilled water.2. Isotonic MgSO4 is no more irritating to the colon than isotonic NaCl as evidenced by histological studies. Its action in producing purgation is probably that of diminishing absorption and thereby producing mechanical stimulation for defæcation by the increased bulk.3. MgSO4 in small doses produces loose and watery stools in cats for several days. This may be due to its effect in slowing the absorption of other crystalloids.4. Solutions of NaCl are best absorbed from the ileum; of glucose, best from the jejunum in cats.5. Decapitate cats cannot be considered to be completely normal with regard to intestinal motility. Washing and excessive handling of the colon tend to make it irritable and give inconsistent results in acute experiments.

Accumulation of Ions. Further Proof of Non-Equilibrium Condition in Valonia.

In a previous paper1 I reported that when living cells of Valonia macrophysa were immersed for periods of 2-3 days in sea water to which had been added isotonic NaCl solution (10-50% by volume) there occurred an increase in the concentration of potassium and a decrease in that of sodium relative to that of chloride. Since these changes were in the direction opposite to those made in the composition of the external medium, it was concluded that this experiment furnished crucial proof that the normal condition in Valonia was not an equilibrium state. The validity of the data has been doubted by Cole on statistical grounds,2 and by Jacques and Osterhout on experimental grounds.3 I have therefore repeated my experiments in the endeavor to meet these criticisms.Experiments were done on Valonia macrophysa at Naples, which tended to confirm my earlier results, but they were unsatisfactory statistically. Recently similar experiments were done on specimens of Valonia ventricosa at Tahiti. These specimens were extr...

Relation of Adrenal Cortex to Development of Scurvy.

It is well known that in scurvy (guinea pigs), marked changes develop in the adrenal. The cortex of this gland is rich in hexuronic acid which has been shown by King to be vitamin C. This vitamin, at least in the guinea pig, is not synthesized to any extent in the body and, therefore, its concentration in the adrenal cortex may be indicative of participation of the latter as an intermediary step in its utilization. If this is true, cortin may play some rôle in the process. To test this hypothesis 3 series of guinea pigs with different amounts of cortin were used. The animals in each group (9 or 10 animals to a group) were balanced for sex and weight and placed on a pre-experimental diet of vitamin C-free ration and lettuce ad libitum, for one week previous to the experiment. At the beginning of the experimental period, the lettuce was discontinued. All animals not injected with extract were injected with one cc. of isotonic NaCl solution twice daily so that they would be subjected to the same manipulation. Series I—Normal amount of cortin (intact adrenals). Group I—Basal diet. Group 2—Basal diet and 0.7 cc. of orange juice daily (one-half protective dose). Series II—Added cortin (by injection). Group 3—Basal diet and 1 cc. of cortin twice daily (40 gm. whole gland per cc). The guinea pigs on the control diet consistently lost weight from the beginning of the experiment which was carried out over a period of 28 days. This is not typical of a negative control series of vitamin C. One or both of 2 factors may have been responsible, the amount of vitamin C obtained from lettuce in the pre-experimental period may not have been optimal or the frequent injections, in animals made sensitive by vitamin C deficiency, may have influenced the appetite.

A Roentgen-Ray Study in Absorption of Thorium Dioxide from Peritoneal Cavity of Albino Rat.

It has long been known that serous cavities have the capacity of absorbing certain injected substances, Cunningham showed that, when a mixture of erythrocytes, large unfiltered carmine granules, and fine lampblack granules, made up in isotonic NaCl solution, was injected into the peritoneal cavity of animals, all 3 types of material reached the anterior mediastinal glands shortly after injection. His results indicate that most, if not all, of the transfer of granular material from the peritoneal cavity into the diaphragmatic lymphatics, during the first 30 minutes, takes place by means of a type of phagocytosis. His important findings give a clearer understanding of the high phagocytic capability of the lymphatic endothelial cells to remove large amounts of particulate matter from the peritoneal cavity. The diaphragm is rich in lymphatics and its lymphatic vessels anastomose with the lymphatic vessels of the pleura and the peritoneum, which, in turn, connects with the right and left lymphatic ducts. The thoracic duct, terminating in the internal jugular vein, conveys the great mass of lymph and chyle into the blood. It is the common trunk of all lymphatic vessels below the diaphragm. The right lymphatic duct receives lymph from the right upper extremity, the right thorax, right lung, right side of the heart, and from parts of the convex surface of the liver. It opens into the junction of the internal jugular and the subclavian veins separately. Absorption in this region is extremely rapid due to this network of lymphatics. The practical application of this knowledge is found in the Fowler position, whereby, upon elevating the head of the bed after operation for abdominal infection, the infected material is permitted to gravitate toward the pelvic peritoneum.

Lowered Resistance to Heat in Adrenal Insufficiency.

Gautrelet and Thomas observed that the rapid breathing usually produced by exposure to high temperatures was absent or very much reduced in the late stages of adrenal insufficiency. In our care of adrenalectomized animals in the laboratory, we have found that high temperatures affect these animals easily. When accidentally overheated, they die before the normal animals. A study has been made of the effect of heat on adrenalectomized rats. When placed in a temperature of 37-40°C. at first both normal and adrenalectomized rats move about the cage. A little later, however, the adrenalectomized animals become quiet and try to sleep, only occasionally moving about. As time goes on the adrenalectomized animals become prostrate while the normal animals show discomfort only by continually moving about the cage and washing themselves with saliva. Frequently the adrenalectomized animals die in a temperature which is not serious for the normals exposed the same length of time. The adrenalectomized animals easily pass into convulsions. At this time convulsions can be brought on by a slight stimulus. Cortical extract can protect adrenalectomized animals to a considerable degree. If cortin injected and sodium chloride injected (0.5 cc. twice daily of extract and isotonic NaCl solutions respectively) rats which have been adrenalectomized are placed in the same high temperature, the difference between the 2 is much like that between normal animals and untreated; adrenalectomized animals except that it is not quite so striking. We are unable at present to explain this increased resistance brought about by cortin. It will be noted that the water content of the blood and muscle shows the least difference in the various groups. The liver comes next while the skin shows the widest differences.

The accumulation of ions in living cells-a non-equilibrium condition

1. Living cells ofValonia macrophysaKutz were exposed for different lengths of time to sea water in which the proportion of potassium had been increased or decreased by the addition of isotonic KC1 or NaCl solutions. 2. The concentration of potassium in the sap ordinarily increased more than that of sodium or chloride regardless of whether it was present in more or less than normal concentration in the surrounding solution. 3. The chloride concentration in the sap ordinarily changed in much the same way as the potassium concentration, but to a significantly smaller extent. 4. The sodium concentration appears to have first increased and then decreased, depending upon the length of exposure and the extent to which the sea water was altered. 5. This may be explained by supposing: (a) the cell to be normally in a non-equilibrium condition with respect to the surrounding solution; (b) to be surrounded by a plasma membrane consisting of a mosaic of anion-permeable and cation-permeable areas which are of the nature of charged porous films, and as such exaggerate differences between the diffusion velocities of the ions to which they are permeable; (c) that the diameters of the pores are variable according to experimental conditions; (d) that the penetrabilities of different ions are characteristic functions of their own effective diameters and of the diameters of the pores in the membranes. 6. This theory is shown to explain more or less completely also the intake of ions by plants, the changes in morphology of green algae grown in darkness, the characteristic ion content of erythrocytes and of neoplastic cells, and the relation between glycolysis and growth of neoplasms.

VII.—A Study of the Fertilisation Membrane in the Echinoderms

Summary1. The view is confirmed that the zona pellucida is not an essential factor in the formation of the fertilisation membrane (pp. 96–100).2. Partial activation of the eggs of Asterias rubens is described with the formation of Seifriz's “protoplasmic papillæ” (pp. 100, 101).3. Artificial activation of the eggs of Asterias rubens by isotonic solutions of NaCl, KCl, CaCl2, and MgCl2 is described. It was found that decrease in surface tension is not a necessary factor in causing artificial membrane formation (pp. 102–104).4. The influence of the hydrogen ion concentration of the medium on the degree of extrusion of the fertilisation membrane of Echinus miliaris has been examined, and indicates that osmotic pressure due to the presence of a protein within the membrane is responsible for the extrusion (pp. 105–109).5. From a study of the influence of salt concentration on the extrusion of the fertilisation membrane of Echinus miliaris, it is concluded that the fertilisation membrane is, from the moment of its formation, completely permeable to salts (pp. 109–112).6. The origin of the fertilisation membrane has been examined, but in the absence of critical evidence it is concluded that the question cannot be regarded as settled (pp. 112–114).

A SIMPLE CASE OF SALT ANTAGONISM IN STARFISH EGGS

The jelly surrounding the eggs of the starfish, Asterias forbesi, is insoluble in normal sea water, but rapidly swells and dissolves when the eggs are washed in a pure isotonic solution of NaCl. In the presence of a small proportion of CaCl(2) this solvent and disintegrative action of the NaCl solution is entirely prevented, and in the mixed solution the jelly exhibits the same insolubility and other properties as in normal sea water. 2. This action of CaCl(2) in preventing the dissolution of the jelly runs parallel with its action in preventing certain definite effects of the pure NaCl solution on the living egg (agglutination, cytolytic action, membrane formation, prevention of maturation). 3. The inference is that the essential factor in these and similar antagonistic and protective actions is the formation of solid water-insoluble colloidal salts (e.g., soaps and proteinates) of calcium (or other metal) with the structural colloids of the protoplasm. Apparently the presence of a certain proportion of such compounds is necessary to the structural stability of the living protoplasm, and especially to the water-insolubility and semipermeability of its external layer or plasma membrane. When the cell is immersed in the pure NaCl solution, water-soluble Na compounds are substituted for the insoluble Ca compounds which normally provide the necessary insolubility and coherence, and disintegration results.

ELECTRIC CHARGES OF THE RED BLOOD CORPUSCLES

ELECTRIC CHARGES OF THE RED BLOOD CORPUSCLES

Studies on salt action. III: The effect of hydrogen ion concentration upon salt action

Our recent studies of the effect of electrolytes upon the viability of bacteria have indicated the important influence of even slight variations in hydrogen ion concentration upon such phenomena. Working with Bact. coli we find that hydrogen ion concentrations above pH = 6.0 or below pH = 7.0 give a much more rapid death rate than occurs when the pH is maintained within these limits. Our experiments suggest that a very careful control of hydrogen ion concentration is absolutely essential before valid conclusions can be drawn as to the influence of electrolytes, alone or in combination.Furthermore, it is essential to follow with care the changes which go on in a suspension of living and dead cells as well as to determine the initial conditions which are provided. We find that a bacterial suspension in 5 isotonic NaCl solution quickly reverts to a pH of about 7.2 whether its initial hydrogen ion concentration be above or below this value. A similar change takes place in a balanced solution of 5 isotonic NaC...