scholarly journals ABNORMAL PROTOPLASMIC PATTERNS AND DEATH IN SLIGHTLY HYPERTONIC SOLUTIONS

1948 ◽  
Vol 31 (3) ◽  
pp. 291-300 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Outer Surface ◽  
Sea Water ◽  
External Solution ◽  
Mechanical Action ◽  
Characteristic Pattern ◽  
Hypertonic Solutions ◽  
Protoplasmic Surface ◽  
Made In

Some interesting properties of protoplasm are revealed when slightly hypertonic solutions of sugars or of electrolytes are applied to Nitella. The chloroplasts contract and the space between them increases and forms a characteristic pattern consisting of clear areas extending lengthwise along the cell and tapering off at both ends. The development of these areas is irreversible from the start. If the cell is returned to water after plasmolysis begins these areas continue to enlarge in much the same fashion as when no change is made in the external solution. The cell soon dies whether returned to water or left in the plasmolyzing solution. Similar results are obtained with other sugars, with NaCl, CaCl2, and sea water. Similar reactions are also brought about by strong ingoing or outgoing currents of water. This suggests that mechanical action may be chiefly responsible for the result and this idea is in harmony with other facts. It seems possible that the retraction of the protoplasm from the cellulose wall may disturb the delicate non-aqueous film which covers the outer surface of the protoplasm and thus produce injury. Such an effect might take place even without visible retraction if the injury occurred in protoplasmic projections extending into the cellulose wall. A study of this behavior may throw light on the nature of the protoplasmic surface and on the properties of protoplasmic gels as well as on the process of death. An understanding of the mechanism involved may help to explain the action of hypertonic solutions in other cases as, for example, in the artificial parthenogenesis of marine eggs.

scholarly journals THE MECHANISM OF ACCUMULATION IN LIVING CELLS

1952 ◽  
Vol 35 (4) ◽  
pp. 579-594 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Osmotic Pressure ◽  
Outer Surface ◽  
Organic Molecules ◽  
Sea Water ◽  
Relative Rate ◽  
Point Of View ◽  
External Concentration ◽  
Protoplasmic Surface ◽  
A Cell ◽  
Outer Protoplasmic Surface

When a compound enters a living cell until its activity becomes greater inside than outside, it may be said to accumulate. Since it moves from a region where its activity is relatively low to a region where its activity is relatively high, it is evident that work must be done to bring this about. The following explanation is suggested to account for accumulation. The protoplasmic surface is covered with a non-aqueous layer which is permeable to molecules but almost impermeable to ions. Hence free ions cannot enter except in very small numbers. The experiments indicate that ions combine at the outer surface with organic molecules (carrier molecules) and are thus able to enter freely. If upon reaching the aqueous protoplasm these molecules are decomposed or altered so as to set the ions free, the ions must be trapped since they cannot pass out except in very small numbers. If we adopt this point of view we can suggest answers to some important questions. Among these are the following: 1. Why accumulation is confined to electrolytes. This is evident since only ions will be trapped. 2. Why ions appear to penetrate against a gradient. Actually there is no such penetration since the ions enter in combination with molecules. The energy needed to raise the activity of entering compounds is furnished by the reactions involved in the process of accumulation. 3. Why, in absence of injury, ions do not come out when the cell is placed in distilled water. Presumably the outgoing ions will combine at the outer surface with carrier molecules and then move inward in the same way as ions coming from without. 4. Why the relative rate of penetration falls off as the external concentration increases. This is because the entrance of ions is limited by the number of carrier molecules but no such limitation exists when ions move outward since they can do so without combining with carrier molecules. 5. Why accumulation is promoted by constructive metabolism which is needed to build up the organic molecules and by destructive metabolism which brings about their decomposition. 6. Why measuring the mobilities of ions in the outer protoplasmic surface does not enable us to predict the relative rate of entrance of ions. We find for example in Nitella that K+ has a much higher mobility than Na+ but the accumulation of these ions does not differ greatly. This is to be expected if they enter by combining with molecules at the surface. Only if K+ is able to combine preferentially will it accumulate preferentially. 7. Why ions may come out in anoxia and at low temperatures. If these conditions depress the formation of carrier molecules and their decomposition in the protoplasm, the balance between intake and outgo of ions will be disturbed and relatively more may come out. 8. Why the excess of internal over external osmotic pressure is less in sea water than in fresh water. As the external concentration of ions increases the rate of intake does not increase in direct proportion since the number of carrier molecules does not increase and this slows down the relative rate of intake of ions. But it does not slow down the rate of exit of ions since they need not combine with carrier molecules in order to pass out. Hence the excess of ions inside will be relatively less as the concentration of external ions increases. 9. How water is pumped from solutions of higher to solutions of lower osmotic pressure. If metabolism and consequently accumulation is higher at one end of a cell than at the other, the internal osmotic pressure will be higher at the more active end and this makes it possible for the cell to pump water from solutions of higher osmotic pressure at the more active end to solutions of lower osmotic pressure at the less active, as shown experimentally for Nitella. This might help to explain the action of kidney cells and the production of root pressure in plants.

scholarly journals THE KINETICS OF PENETRATION

1937 ◽  
Vol 20 (5) ◽  
pp. 737-766 ◽  
Author(s):  
A. G. Jacques
Keyword(s):  
Sea Water ◽  
Surface Layers ◽  
Marked Contrast ◽  
External Concentration ◽  
Protoplasmic Surface ◽  
Kinetics Of ◽  
External Ph

When 0.1 M NaI is added to the sea water surrounding Valonia iodide appears in the sap, presumably entering as NaI, KI, and HI. As the rate of entrance is not affected by changes in the external pH we conclude that the rate of entrance of HI is negligible in comparison with that of NaI, whose concentration is about 107 times that of HI (the entrance of KI may be neglected for reasons stated). This is in marked contrast with the behavior of sulfide which enters chiefly as H2S. It would seem that permeability to H2S is enormously greater than to Na2S. Similar considerations apply to CO2. In this respect the situation differs greatly from that found with iodide. NaI enters because its activity is greater outside than inside so that no energy need be supplied by the cell. The rate of entrance (i.e. the amount of iodide entering the sap in a given time) is proportional to the external concentration of iodide, or to the external product [N+]o [I-lo, after a certain external concentration of iodide has been reached. At lower concentrations the rate is relatively rapid. The reasons for this are discussed. The rate of passage of NaI through protoplasm is about a million times slower than through water. As the protoplasm is mostly water we may suppose that the delay is due chiefly to the non-aqueous protoplasmic surface layers. It would seem that these must be more than one molecule thick to bring this about. There is no great difference between the rate of entrance in the dark and in the light.

On the Vitelline Membrane of the Egg of Psammechinus Miliaris and of Teredo Norvegica

1932 ◽  
Vol 9 (1) ◽  
pp. 93-106
Author(s):  
A. D. HOBSON
Keyword(s):  
Sea Water ◽  
Tap Water ◽  
Elastic Solid ◽  
Vitelline Membrane ◽  
Hypertonic Solution ◽  
Perivitelline Space ◽  
Free Zone ◽  
Hypertonic Solutions ◽  
Psammechinus Miliaris ◽  
Entire Cell

I. Direct microscopic examination of the unfertilised eggs of Psammechinus miliaris and Teredo norvegica merely shows the existence of a thin, granule-free zone covering the surface. Whether this is continuous with the general cytoplasm or not cannot be made out with certainty by direct observation. 2. A cone of clear material can be drawn out from the surface of the unfertilised egg of both species by means of the microdissection needle. A definite membrane cannot be separated in this way. 3. Hypertonic solutions cause the egg of Psammechinus to shrink smoothly at first and later to become wrinkled. This is consistent with the view that the egg is surrounded by an elastic, solid layer which is normally in a state of tension. 4. Cytolysis of the egg of Psammechinus in tap water is not accompanied by bursting. The egg swells and is perfectly smooth and spherical when cytolysis is completed. This points to the existence of an elastic, solid surface layer. 5. Plasmolysis of the egg of Teredo is of the type here called "polyhedral."The irregular shape of the egg in the hypertonic solution is only temporary, as a clear membrane separates from the concave surfaces and the egg then becomes more or less spherical. 6. The protoplasm of the plasmolysed egg of Teredo behaves as a viscous fluid. 7. Cytolysis of the egg of Teredo in tap water is accompanied by bursting and dispersion of the entire cell contents. A crumpled membrane alone remains. 8. It is concluded that the unfertilised egg of both Teredo norvegica and Psammechinus miliaris is surrounded by an elastic vitelline membrane which is much a Vitelline Membrane of the Egg of P. miliaris and of T. norvegica 105 thicker in the former than in the latter. The vitelline membrane in both cases is tightly attached to the egg surface. 9 . In calcium-free sea water the fertilisation membrane is elevated normally in Psammechinus miliaris. It does not harden, however, and gradually sinks back on to the surface of the egg owing, apparently, to the loss by diffusion of the osmotically active substance in the perivitelline space. It can be elevated a second time by puncturing the surface of the egg and allowing some of the cell contents to penetrate into the perivitelline space. 10. It is suggested that one action of hypertonic solutions in inducing artificial parthenogenesis may be to cause a loosening of the attachment of the vitelline membrane to the egg surface.

“Conjoint Gas and Mechanical Action as Applied to Flight”

1884 ◽  
Vol 19 ◽  
pp. 96-100
Author(s):  
Fred. W. Brearey
Keyword(s):  
United States ◽  
Patent Protection ◽  
The United States ◽  
Mechanical Action ◽  
United States Patent ◽  
Model Form ◽  
Patent Laws ◽  
States Patent ◽  
Mechanical Arrangement ◽  
Made In

The remarks made in this paper are due to the action of the United States Patent Laws, as interpreted by one of the examiners, whose duty it was to adjudicate upon the practicability of an invention submitted to him, and whose decision was adverse to the granting of a patent. Protection was solicited for an improvement upon a previously patented mechanical aërial machine, the success of which had been proved by the inventor through the action of a model. The patent was refused on account of the alleged impracticability of the invention owing to the absence of gas as a supporting, or partly supporting, medium. Total misapprehension of the principles of flight is displayed whenever the balloon is recommended to take off part of the weight of any mechanical arrangement. However successfully the pure mechanical action may have proved itself in the conveyance of weights in the air whilst in the model form, the principle seems to be distrusted by some when proposed for extreme weight. But it fortunately happens that the resistance of the air to a body in motion, upon which we depend for success, bears a greatly increasing ratio to the extent of surface which that body assumes.

scholarly journals III. On the determination, at sea, of the specific gravity of sea-water

1875 ◽  
Vol 23 (156-163) ◽  
pp. 301-308 ◽  
Keyword(s):  
Specific Gravity ◽  
Physical Condition ◽  
Sea Water ◽  
Accurate Determination ◽  
Actual Difference ◽  
Made In

In the investigation of the physical condition of the ocean the accurate determination of the specific gravity of the water holds a first place. The tolerably numerous observations which have been made in this direction, in a more or less connected manner, are sufficient to prove that the density of the water varies, not only with the latitude and longitude, but also with the distance from the surface of the source from which it is taken. This difference of density depends partly on an actual difference in saltness, and partly on a difference in temperature of the water.

scholarly journals ACTION CURVES WITH SINGLE PEAKS IN NITELLA IN RELATION TO THE MOVEMENT OF POTASSIUM

1940 ◽  
Vol 23 (6) ◽  
pp. 743-748 ◽  
Author(s):  
W. J. V. Osterhout ◽  
S. E. Hill
Keyword(s):  
Outer Surface ◽  
Distilled Water ◽  
Protoplasmic Surface ◽  
Outer Protoplasmic Surface ◽  
Two Peaks

In Nitella the action curve has two peaks, apparently because both protoplasmic surfaces (inner and outer) are sensitive to K+. Leaching in distilled water makes the outer surface insensitive to K+. We may therefore expect the action curve to have only one peak. This expectation is realized. The action curve thus obtained resembles that of Chara which has an outer protoplasmic surface that is normally insensitive to K+. The facts indicate that the movement of K+ plays an important part in determining the shape of the action curve.

Mechanical Action on the Air

1879 ◽  
Vol 14 ◽  
pp. 16-24
Keyword(s):  
Mechanical Action ◽  
Made In ◽  
Scientific Advances

My studies and experiments in that most interesting science. Practical Aërostation, have been wholly in reference mechanical action on the air, and the motive power most suitable for that purpose.In my brief address I make no reference to the buoyance balloon principle, yet I may express pride and satisfaction that scientific advances made in aërostatic science—thanks some Members of our Society, and to other pioneers—have lend to the adoption and commission of balloons in Her Majesty Service.I have made an instrument for testing captive vanes–which I may call the flight–meter—the use of which is to detemine the relative properties of lifting and propelling vanes various forms and various angular pitches, with vanes one foot or less from tip to tip; by turning a handle a velocity of one to two miles a minute is delivered on the air.

On F2Echinus Hybrids

1914 ◽  
Vol 10 (3) ◽  
pp. 464-465 ◽  
Author(s):  
H. M. Fuchs
Keyword(s):  
Second Generation ◽  
Sea Water ◽  
Hybrid Generation ◽  
Marine Biological Laboratory ◽  
Marine Biological ◽  
Biological Laboratory ◽  
The Cross ◽  
One Year ◽  
Sexually Mature ◽  
Made In

An investigation on inheritance in hybrids between the three English species of Echinus was carried out in the Marine Biological Laboratory, Plymouth, during 1909–1912 by C. Shearer, W. de Morgan, and H. M. Fuchs. In a paper published in the Phil. Trans. Royal Soo., Ser. B, Vol. CCIV., p. 255, the results of this work were described in detail. At the time of publication, E. miliaris had been raised from the egg to maturity in the laboratory, in the course of one year, and a second generation had been obtained from these individuals, but none of the hybrid urchins had as yet reached maturity. This year, however, some of the hybrids have become sexually mature, and from them a second hybrid generation has been raised.The urchins which have formed ripe genital products are four individuals of the cross E. esculentus X E. acutus (referred to below as EA) derived from fertilizations made in 1912. The largest of these urchins now measures 6 cm. in diameter, exclusive of the spines. On May 11th, 1914, two of these hybrids laid eggs in the tank in which they were kept. Naturally these eggs could not be used for experimental purposes, since they were deposited in the sea water of the aquarium circulation, and therefore not under sterile conditions. On June 6th I induced three of the four to deposit genital products without cutting them open, under conditions which excluded the possible presence of foreign eggs or spermatozoa. It is hardly necessary to mention here that, as in all the previous work on Echinus hybrids, the fact of the complete absence of such sperm was made certain by controls of unfertilized eggs, none of which segmented.

Reducing Activity and the Formation of Base in the Shore Crab, Carcinus Maenas

1985 ◽  
Vol 65 (2) ◽  
pp. 505-530 ◽  
Author(s):  
Peter S. B. Digby
Keyword(s):  
Outer Surface ◽  
Biological Material ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Water Salinity ◽  
Shore Crab ◽  
Calcareous Deposits ◽  
Reducing Activity ◽  
Diffusion Potentials ◽  
Active Processes

Crustacean cuticle consists essentially of chitin impregnated and coated with protein which is tanned with quinone (Dennell, 1947a). The outer surface is most heavily tanned, and the cuticle is further strengthened by calcification. The various theories as to the mechanism of calcification in crustacean and other biological material have been reviewed briefly by Digby (1967). Most appear unsatisfactory for various reasons, and evidence was outlined that calcification might arise from the formation of base by processes which are essentially electrochemical in origin. The quinone-tanned protein of the cuticle is electrically semiconducting and supports electrode action in suitable gradients of potential (Digby, 1965), and small potential differences may arise by diffusion or by active processes. Thus the deposition of calcareous salts might arise partly at least by action comparable to that which takes place at a metallic cathode. In support of this, the position of the initial calcareous deposits in Carcinus maenas (L.) was found to change with the gradient of sea-water salinity in the manner expected if some control were exercised by diffusion potentials, acting across a thin semiconducting layer to generate small changes of pH (Digby, 1968).

scholarly journals PROTOPLASMIC POTENTIALS IN HALICYSTIS

1929 ◽  
Vol 13 (2) ◽  
pp. 223-229 ◽  
Author(s):  
L. R. Blinks
Keyword(s):  
Outer Surface ◽  
Sea Water ◽  
Inner Surface

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.

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