bluuebunny/crossref_metadata_2025 huggingface dataset:
DIFFUSION POTENTIALS IN MODELS AND IN LIVING CELLS
Authors: Osterhout W. J. V.
Published: May 2004

The behavior of guaiacol resembles that of certain protoplasmic surfaces to such an extent that it can be advantageously used in models designed to imitate certain aspects of protoplasmic behavior. In these models the electrical potentials appear to consist of diffusion potentials and this may be true of certain living cells.

In dealing with models we determine ionic mobilities and use these to predict potentials.

In studying living cells we measure potentials and from these calculate ionic mobilities. The question arises, how far is this method justified. To test this we have treated guaiacol like a living cell, measuring potentials and from these estimating ionic mobilities.

The results Justify the use of this method. This is of interest because the method is most useful in studying protoplasmic activity. In its extended form it enables us to follow changes in mobilities and in partition coefficients due to applied reagents and to metabolism.
DERIVED PHOTOSENSITIVE PIGMENTS FROM INVERTEBRATE EYES
Authors: Bliss Alfred F.
Published: May 2004

The red pigment in the eyes of the squid, blue crab, and horseshoe crab becomes photosensitive when treated with formalin, and bleaches in the light. The resulting change in density is approximately symmetrical around a maximum at 480 mµ in the blue green. This difference absorption spectrum is in rough agreement with the spectral sensitivity of the cephalopod eye and differs only slightly from the difference absorption spectrum of vertebrate visual purple.

The formalin-sensitized pigment is not melanoid. Its bleaching in squid retinas releases large quantities of retinene.

It is suggested that the light sensitivity of the normal squid photopigment may be independent of its light stability.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Abrams Irving , Sollner Karl
Published: May 2004

1. Strongly electropositive porous membranes were prepared by the adsorption of protamine (salmine) on porous collodion membranes. These membranes retain their electrochemical chracteristics for at least 12 months without change.

2. They are distinctly electropositive between pH 1 and 10, the range of most pronounced electropositive behavior occurring in solutions between pH 3 and pH 8. The filtration rates and ohmic resistance of these membranes do not differ significantly from similar uncoated membranes.

3. The porous protamine-collodion membranes show very pronounced positive anomalous osmosis, the observed effects with proper electrolytes being similar to those obtained with oxidized collodion membranes. They also show very conspicuous negative osmosis with strong acids.

4. Protamine-collodion membranes which correspond in their properties to the activated dried collodion membranes were prepared by the adsorption of protamine on porous collodion membranes followed by drying in air. The concentration potentials across such dried protamine-collodion membranes closely approach the thermodynamically possible maximum.
SOME THERMOANALYTIC STUDIES OF ORGAN AND WHOLE ANIMAL RESPIRATION
Authors: Morales Manuel F.
Published: May 2004

Data on the respiratory rates of frog liver, kidney, and striated muscle were obtained at various temperatures by the Warburg method. Fundamental differences in the curves of QOO2 vs. T exist among the tissues and between the tissues and the whole animal. The Arrhenius plots of these curves show that at least for some tissues the availability of oxygen at the tissue, as limited by the diffusion of gas through the skin and lungs, governs the QOO2 of the tissue. Inferences are drawn regarding the comparative metabolism of the tissues and the fallacy of using whole animal QOO2 alone as a metabolic index.
THE ANTIPROTEOLYTIC ACTIVITY OF SERUM
Authors: Grob David
Published: May 2004

1. An equation is derived for the calculation of a constant which, experimental results indicate, may be a more reliable index of the antiproteolytic activity of serum than those equations hitherto used.

2. (a) Intramuscular administration of trypsin resulted in a slow rise in the antiproteolytic activity of the serum, followed by a lesser decline. (b) Intravenous administration resulted in no appreciable variation. (c) Oral administration resulted in a rapid rise, which was sustained during the period of administration. (d) Intramuscular, intravenous, or oral administration of denatured trypsin resulted in no appreciable variation. (e) The extent of the local necrosis following subcutaneous injection of trypsin varied inversely with the antiproteolytic activity of the serum.

3. The experimental results indicate that the products of protein hydrolysis in the intestine and parenterally are an important factor in the antiproteolytic activity of the serum. They also indicate that antibodies to trypsin are not an important factor in the antiproteolytic activity of the serum.
THE EFFECT OF LOW OXYGEN TENSION ON TISSUE METABOLISM (RETINA)
Authors: Craig Francis N. , Beecher Henry K.
Published: May 2004

Lactic acid production by rat retina in a medium containing phosphate was studied chemically. One half as much lactic acid was found as in a medium containing bicarbonate. In our experience the rate of respiration in a phosphate medium was sensitive to oxygen tension, for it was 38 per cent lower at 10 per cent and 51 per cent lower at 5 per cent oxygen than at 100 per cent oxygen. Previously Laser had reported no decrease in respiration at 5 per cent oxygen in phosphate medium. In phosphate medium, when the oxygen tension was varied, respiration and glycolysis bore a reciprocal relationship to each other.

In bicarbonate medium, when the oxygen tension was lowered from 95 per cent to 5 per cent there was no significant change in the respiration, but glycolysis was increased nearly to the anaerobic level. This agrees with the earlier experiment of Laser in bicarbonate medium and adds support to his conclusion that the rate of glycolysis is controlled by oxygen tension rather than by the rate of respiration, under the conditions of the experiment.
THE EFFECT OF CARBON DIOXIDE TENSION ON TISSUE METABOLISM (RETINA)
Authors: Craig Francis N. , Beecher Henry K.
Published: May 2004

The metabolism of rat retina was found to be sensitive to the concentration of the carbon dioxide-bicarbonate buffer system. Increasing the carbon dioxide from 1 per cent to 5 per cent at constant pH nearly doubled both respiration and glycolysis. Increasing the carbon dioxide at constant pH from 5 per cent to 20 per cent had no effect on glycolysis, but depressed the QOO2 from 31 to 19.

In a medium containing glucose and the 1 per cent carbon dioxide-bicarbonate buffer, the addition of succinate increased the QOO2 from 12 to 26, without affecting glycolysis. In a medium containing glucose and phosphate, succinate had no significant effect.
THE INFLUENCE OF AMINO ACIDS ON THE REACTIVATION OF YEAST INVERTASE
Authors: Wagreich Harry , Halpert Wesley , Hirschman Albert
Published: May 2004

1. Some 16 amino acids (not containing SH or S-S groups) did not affect the reactivation of yeast invertase inactivated by acid.

2. Cysteine, reduced glutathione, homocysteine, thiophenol, and thioglycollic acid accelerated the reactivation of yeast invertase.

3. Cystine, oxidized glutathione, and homocystine inhibited the reactivation of yeast invertase.

4. The compounds mentioned in 2 and 3 did not affect native invertase.

5. The use of compounds in which the H of the SH group of homocysteine was substituted by a methyl or benzyl nullified the accelerative effect.

6. The longer the cysteine remained in contact with the inactivating enzyme, the greater was the velocity of the reactivated invertase.

7. The per cent acceleration by cysteine is inversely proportional to the control rate.
DIFFERENTIAL SENSITIVITY OF PROPHASE POLLEN TUBE CHROMOSOMES TO X-RAYS AND ULTRAVIOLET RADIATION
Authors: Swanson C. P.
Published: May 2004

1. Through use of the pollen tube technique it has been possible to study the sensitivity of prophase stages to x-rays and ultraviolet, and to correlate the varying sensitivity with changes in the generative nucleus of Tradescantia.

2. Sensitivity to ultraviolet decreases from the 2 hour stage until at 11 hours after germination there is no further production of breaks. The 0 and 1 hour stages show a decreased sensitivity over the 2 hour stage but it has been suggested that this is not due to a decreased sensitivity but to shielding by the pollen wall.

3. Sensitivity to x-rays rises to a peak at the 4 hour stage, but then subsides until no breaks are realized (at a dose of 370.8 r) after the 10 hour stage. In this respect the effects of x-rays and ultraviolet are similar. Each type of x-ray break shows its own individual trend.

4. Correlation of x-ray breaks with changes in the generative nucleus indicates that the important events determining the sensitivity of the chromosomes to breakage are the uptake of water at the time of germination and the movement involved in spiralization. The total absence of breaks after the 11 hour stage is not understood.

5. The changing sensitivity to ultraviolet may depend on any one or all of three factors: (a) the nucleic acid cycle, (b) changes in the matrix, and (c) the number of subdivisions in the chromosome. These are discussed although their relative importance is not known.
PHYSICAL PROPERTIES OF THE ALLANTOIC AND AMNIOTIC FLUIDS OF THE CHICK
Authors: Walker Paul Andrew
Published: May 2004

1. The specific conductance of the allantoic and amniotic fluids of the developing chick has been determined over the period of incubation between the 7th and 19th days.

2. Changes in this property have been related to changes in the chemical composition of these two fluids.

3. These conductance values are of importance in that they show the relation between ionized and un-ionized materials present in the two fluids.
NATIVE AND REGENERATED BOVINE ALBUMIN
Authors: Putnam Frank W. , Erickson John O. , Volkin Elliot , Neurath Hans
Published: May 2004

1. Whole bovine albumin, homogeneous in diffusion and sedimentation, and essentially homogeneous in electrophoresis, has been prepared by a method involving ammonium sulfate precipitation of the globulins in the cold and of the albumin at room temperature, isoelectric precipitation of the euglobulins, and reprecipitation of the albumin.

2. The product has been characterized by chemical analysis and by viscosity, diffusion, sedimentation, and electrophoresis measurements. The carbohydrate content is 0.38 per cent, the nitrogen content, 15.2 per cent. The molecular shape approximates that of a prolate ellipsoid with an axial ratio of 3.1, assuming 33 per cent hydration; the average molecular weight is 65,000.

3. Bovine albumin is readily denatured by concentrated solutions of urea or guanidine hydrochloride, gross changes in molecular shape resulting.

4. Regeneration of bovine albumin denatured in solutions of 8 M urea or guanidine hydrochloride yields a material closely resembling the native in carbohydrate content, in molecular size and shape, and in electrophoretic properties. However, the regenerated protein differs from the native in susceptibility to tryptic digestion, and, in this respect, appears to be in a denatured state.

5. In 8 M solutions of guanidine hydrochloride a limiting yield of regenerated albumin equivalent to 95 per cent of the original protein is approached.

6. Bovine crystalbumin, a crystalline carbohydrate-free fraction of the whole albumin, appears to be more susceptible to denaturation than whole bovine albumin.
POTENTIAL, IMPEDANCE, AND RECTIFICATION IN MEMBRANES
Authors: Goldman David E.
Published: May 2004

Impedance and potential measurements have been made on a number of artificial membranes. Impedance changes were determined as functions of current and of the composition of the environmental solutions. It was shown that rectification is present in asymmetrical systems and that it increases with the membrane potential. The behavior in pairs of solutions of the same salt at different concentrations has formed the basis for the studies although a few experiments with different salts at the same concentrations gave results consistent with the conclusions drawn.

A theoretical picture has been presented based on the use of the general kinetic equations for ion motion under the influence of diffusion and electrical forces and on a consideration of possible membrane structures. The equations have been solved for two very simple cases; one based on the assumption of microscopic electroneutrality, and the other on the assumption of a constant electric field. The latter was found to give better results than the former in interpreting the data on potentials and rectification, showing agreement, however, of the right order of magnitude only. Although the indications are that a careful treatment of boundary conditions may result in better agreement with experiment, no attempt has been made to carry this through since the data now available are not sufficiently complete or reproducible. Applications of the second theoretical case to the squid giant axon have been made showing qualitative agreement with the rectification properties and very good agreement with the membrane potential data.
DENATURATION CHANGES IN EGG ALBUMIN WITH UREA, RADIATION, AND HEAT
Authors: Clark Janet H.
Published: May 2004

The extent of urea denaturation depends on the concentration of protein and urea and also on the temperature of the solution. Egg albumin solutions (0.9 per cent) are not denatured by 20 per cent urea, denature slowly with 25 per cent urea, and denature rapidly with 35 per cent urea at room temperature. At a higher temperature 30 per cent urea is rapidly effective.

Denaturation of the egg albumin molecule by radiation or by heat is accompanied by structural changes as evidenced by optical rotation values, but is not accompanied by association or dissociation of the molecule in the pH range outside the zone in which aggregation follows denaturation.

Denaturation of the egg albumin molecule by urea produces no change in optical rotation until the concentration of urea is high enough to dissociate the molecule.

In the presence of urea a urea-protein complex is formed in which the protein is denatured but cannot flocculate because of the dispersive action of the urea. This prevents flocculation of proteins exposed to radiation and subsequent heating to 40° C. as the urea-protein complex is not broken down at a temperature of 40° C. The presence of urea therefore prevents the flocculation of proteins denatured by radiation.

The urea-protein complex is broken down by heating to 55–58° C. so that the molecules aggregate at a temperature below the temperature of rapid heat denaturation. This appears to be an acceleration of heat denaturation or a lowering of the heat denaturation temperature, but in reality is an effect of heat on the urea-protein complex which frees the urea-denatured protein and permits its aggregation.
STUDIES OF THE INNER AND OUTER PROTOPLASMIC SURFACES OF LARGE PLANT CELLS
Authors: Osterhout W. J. V.
Published: May 2004

In Nitella, Chara, Hydrodictyon, and Valonia the inner and outer non-aqueous protoplasmic surface layers can be separated by certain plasmolytic agents which penetrate the outer surface more rapidly than the inner and hence raise the osmotic pressure of the protoplasm lying between them and cause it to increase in thickness by taking up water from the central vacuole.

We may therefore conclude that the two surfaces differ. This idea is confirmed by earlier electrical measurements which show that when sap is placed outside the cell the chain

See PDF for Structure

produces an E.M.F. of several millivolts.
A MODEL OF THE POTASSIUM EFFECT
Authors: Osterhout W. J. V.
Published: May 2004

The protoplasm of certain cells is able to distinguish electrically between K+ and Na+. This has been called the potassium effect.

This is illustrated by experiments with Nitella. When 0.01 M KCl which has stood in contact with Nitella is replaced by 0.01 M NaCl the P.D. changes in a positive direction by an amount which varies between 30 and 95 mv. This ability to distinguish between K+ and Na+ disappears with the removal of an organic substance from the cell. The amount of this substance is doubtless too small to make it possible to obtain enough for analysis. An attempt has therefore been made to find an organic compound which can produce similar effects.

It is found that when M/1 KCl in contact with nitrobenzene (previously shaken with M/1 KCl) is replaced by M/1 NaCl the potential changes in a positive direction to the extent of 67 mv. which compares favorably with the values found in Nitella.

This is not due to a greater mobility in nitrobenzene of K+ as compared with Na+: this is evident from measurements of concentration effects with nitrobenzene (M/1 KCl vs. M/10 KCl and M/1 NaCl vs. M/10 NaCl). It might be brought about if KCl produced in nitrobenzene a sufficient preponderance of ions (simple or complex) as compared with NaCl. Whether this occurs could not be determined but it was found that nitrobenzene shaken with M/1 KCl has a higher conductivity than when shaken with M/1 NaCl.

Measurements with salicylates showed that K-salicylate has a partition coefficient about 11.7 times as great as that of Na-salicylate. It was also found that when M/1 K-salicylate in contact with nitrobenzene (previously shaken with M/1 K-salicylate) is replaced by M/1 Na-salicylate there is a change of potential in a positive direction amounting to 56 mv.

To what extent phase boundary potentials may enter into the observed values cannot be determined at present.

The model resembles the Nitella cell in that RbCl and KCl are negative to NH4Cl which in turn is negative to NaCl and still more so to LiCl (in the model CsCl is negative to KCl but in Nitella it is positive).

It likewise resembles Nitella in that the potassium effect is lessened by the addition of guaiacol.
HOMEOSTATIC ADJUSTMENTS AFTER EXERCISE
Authors: Shock Nathan W.
Published: May 2004

The rate at which displacement and recovery of the acid-base equilibrium of the blood occur in young adult males subjected to short periods of maximal exertion has been determined.

Displacement of acid-base equilibrium produced by severe exercise is along the fixed acid path, similar to the path of displacement produced by ingestion of acidifying agents such as ammonium chloride.

Maximum displacement of the acid-base equilibrium is not reached until 7 to 10 minutes after the cessation of exercise. By this time over 50 per cent of the displacement in oxygen consumption, respiratory volume, and blood pressure have disappeared.

A much greater metabolic acidosis was produced by exercise than could be induced by the oral administration of ammonium chloride.

Recovery from the metabolic acidosis produced by exercise was much more rapid (10 times) than was recovery from the acidosis produced by ammonium chloride.

After exercise the pH, returned to normal values more rapidly than did the bicarbonate content of the serum.
A PHYSICAL THEORY OF ACID ANION DISPLACEMENT AND RECOVERY FOLLOWING EXERCISE
Authors: Morales Manuel F. , Shock Nathan W.
Published: May 2004

A simple theoretical model has been presented whose behavior duplicates the variation in bicarbonate ion concentration in the blood following exercise. Methods for the evaluation of the constants of rational equations to describe the concentration in muscle cells, in blood plasma, and in removal cells, of the anions produced in exercise have been devised. These methods have been applied to experimental data from 23 experiments, and a close agreement between the observed and theoretically predicted values for blood plasma has been found. From the mathematical analysis of the data values for permeability of acid anions produced in exercise have been estimated as 75 x 10–5 and 5.9 x 10–5 cm. per sec. between muscle cell and blood (extracellular fluid) and between blood plasma and removal cells respectively.
THE PREPARATION AND PROPERTIES OF HIGHLY PURIFIED ASCORBIC ACID OXIDASE
Authors: Powers Wendell H. , Lewis Stanley , Dawson Charles R.
Published: May 2004

1. A method is described for the preparation of a highly purified ascorbic acid oxidase containing 0.24 per cent copper.

2. Using comparable activity measurements, this oxidase is about one and a half times as active on a dry weight basis as the hitherto most highly purified preparation described by Lovett-Janison and Nelson. The latter contained 0.15 per cent copper.

3. The oxidase activity is proportional to the copper content and the proportionality factor is the same as that reported by Lovett-Janison and Nelson.

4. When dialyzed free of salt, the blue concentrated oxidase solutions precipitate a dark green-blue protein which carries the activity. This may be prevented by keeping the concentrated solutions about 0.1 M in Na2HPO4.

5. When highly diluted for activity measurements the oxidase rapidly loses activity (irreversibly) previous to the measurement, unless the dilution is made with a dilute inert protein (gelatin) solution. Therefore activity values obtained using such gelatin-stabilized dilute solutions of the oxidase run considerably higher than values obtained by the Lovett-Janison and Nelson technique.

6. The effect of pH and substrate concentration on the activity of the purified oxidase in the presence and absence of inert protein was studied.
STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS
Authors: Dainty Mary , Kleinzeller Arnost , Lawrence A. S. C. , Miall Margaret , Needham Joseph , Needham Dorothy M. , Shen Shih-Chang
Published: May 2004

1. An investigation of the physicochemical properties of myosin has been carried out. Prepared under standard conditions, the ratio of flow-birefringence to protein concentration is uniform. The effect of electrolytes, pH, and urea on the flow-birefringence and viscosity (relative and anomalous) of myosin has been examined.

2. Decrease or abolition of flow-birefringence does not necessarily imply far reaching denaturation, since such effects can be reversed by a variety of means.

3. When a myosin solution is treated with adenosinetriphosphate, its flow-birefringence is decreased (average 48 per cent), its anomalous viscosity is retained, and its relative viscosity is decreased (average 14 per cent). The full effect of adenosinetriphosphate is obtained at 0.004 M; a molarity very much less than that of other substances which decrease the flow-birefringence of myosin.

4. The changes in the physicochemical properties of myosin brought about by adenosinetriphosphate are spontaneously reversible, and are connected with the enzymatic action of the protein as adenosinetriphosphatase.

5. Effects similar to those of adenosinetriphosphate on the physicochemical properties of purified myosin have been obtained so far only with inosinetriphosphate.

6. Inorganic phosphate is split off by myosin from inosinetriphosphate as well as from adenosinetriphosphate. Inorganic triphosphate is split by 1 to 2 per cent solution of three times precipitated myosin.

7. Adenosinediphosphate and inorganic triphosphate act as competitive inhibitors with adenosinetriphosphate, blocking the fall of flow-birefringence.

8. The implications of the results, and the conception of active enzymic groups attached to proteins participating in cell structure, whether contractile or non-contractile, are discussed in relation to present views on muscle physiology and other biological problems.
THE EFFECT OF URETHANE ON THE CONSUMPTION OF OXYGEN AND THE RATE OF CELL DIVISION IN THE CILIATE TETRAHYMENA GELEII
Authors: Ormsbee Richard A. , Fisher Kenneth C.
Published: May 2004

1. The inhibition of oxygen consumption produced by a series of concentrations of ethyl carbamate has been measured in the protozoan Tetrahymena geleii.

2. The relation found between the narcotic concentration and its effect on respiration leads to the conclusion that urethane has two distinct modes of action in this cell. The respiratory data can be accurately predicted by assuming that the inhibitor acts on two independent parallel respiratory systems.

3. Complete suppression of cell division in this organism is brought about by approximately 0.1 M urethane.

4. Urethane concentrations up to 0.1 M affect primarily only one of the two postulated respiratory systems. The mechanism of the narcosis of cell division in this organism by urethane thus appears to be inhibition of this "activity" system.
THEORY AND MEASUREMENT OF VISUAL MECHANISMS
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

Flicker contours from vertebrates (fishes to man) show that the slope parameter σ'log I in the efficiently descriptive probability summation 100 F/Fmax. = ∫–inf;log I e–(log I/Ii)–(log I/Ii)2/2(σ')/2(σ')2 ·d log I is distributed bimodally (simple fields, "white" light), from 0.60 to 2.3, with well defined peaks at 0.80 and 1.75. This parameter is independent of Fmax., log Ii, temperature, light-time fraction, and in general not greatly influenced by λ. "Rod" components of known visually duplex contours, without exception, and some "cone" contours, are in the first group; an equal number of "cone" curves are in the second group, together with one simplex "rod" contour; purely cone contours are in each group, as well as cone segments of duplex curves. No firm zoological grouping of the "cone" curves can be made, on present evidence,—although the 5 fishes used give high-slope curves, 2 amphibians low slopes, reptiles (5) either high or low, birds (2) and anthropoids (2) low-slope "cone" curves.

By subdivision of the visual image and by change of wave-length, under certain conditions, in man, and by use of the "pecten effect" in birds (and man), cone contours of the low-slope class can be transformed into curves of the high-slope group. These procedures do not fundamentally change the "rod" slopes.

Consequently, although under simple conditions they are specifically determined, the forms of the F - log I contour cannot be used as diagnostic for rod or cone functioning. It is reinforced, by new data on Anolis (lizard) and Trionyx (turtle), that an obviously duplex retina is specifically correlated with a duplex performance contour, a simplex retina with a simplex one. But no support is given to the view that the shapes of these curves are diagnostic of differences in rod or cone fundamental excitabilities, or that they describe properties of these units. In visual duplexity we have to do simply with the fact that two groups of neural effects are available; it is with their properties that we deal in measurements of duplex visual excitability.
ACTION OF POTASSIUM AND NARCOTICS ON RECTIFICATION IN NERVE AND MUSCLE
Authors: Guttman Rita
Published: May 2004

Electrical rectification was demonstrated in whole sartorius muscle and sciatic nerve of Rana pipiens and also in the single giant nerve fiber of the northern squid, Ommastrephes illecibrossus. It is probably a property of the plasma membrane.

Rectification decreases reversibly under the influence of increased concentrations of the potassium ion and with chloroform, veratrine sulfate and isoamyl carbamate. No effect was found with lack of calcium, excess calcium, or barium chloride.

Decrease in rectification is invariably accompanied by simultaneous decrease in resting potential.

A proposed explanation of the mechanism of rectification is discussed. Rectification in a living membrane, viz. a change in resistance with change in direction of current flow, may possibly be explained in terms of a change in the concentration of potassium ions in the membrane.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Carr Charles W. , Sollner Karl
Published: May 2004

1. The electronegative membranes described in the literature which show a high degree of ionic selectivity (permitting cations to pass and restricting the anions) have serious shortcomings: their absolute permeability is extremely low, much too small for convenient experimentation; their ionic selectivity in most cases is not as perfect as would be desirable, and is moreover adversely affected by prolonged contact with electrolyte solutions.

2. A method has been worked out to prepare membranes substantially free from these defects. Porous collodion membranes were cast on the outside of rotating tubes and then oxidized with 1 M NaOH. By allowing the oxidized porous membranes to dry in air on the tubes membranes of desirable properties are obtained. These membranes are smooth, have a well defined shape, and allow considerable handling without breaking.

3. This new type membrane when tested for ionic selectivity by the measurement of the "characteristic concentration potential," consistently gives potentials of 54 to 55 mv., the maximum thermodynamically possible value (at 25°C.) being 55.1 mv. This high degree of ionic selectivity is not lost on prolonged contact with water, and is only very slowly affected by electrolyte solutions.

4. The absolute permeability of the new type membranes can be varied over a very wide range by changing the time of oxidation. Under optimum conditions membranes can be obtained with a resistance in 0.1 N KCl solution of only 0.5 ohms per 50 cm.2 membrane area. The absolute rate of cation exchange through these membranes between solutions of different uni-univalent electrolytes is very high, in one case, e.g. 0.9 m.eq. cations per 4 hours, the anion leak being 0.02 m.eq. Thus, the absolute permeability of the new type membranes is two to four orders of magnitude greater than the permeability of the dried collodion membranes and the oxidized ("activated") dried collodion membranes used heretofore. Because of the characteristic properties of the new type membranes the term "megapermselective" (or "permselective") collodion membranes is proposed for them.
CHANGES IN THE APPARENT CYTOPLASMIC HYDROGEN ION CONCENTRATION OF AMEBA DUBIA ON INJECTION OF EGG ALBUMIN
Authors: Marshak A.
Published: May 2004

1. Egg albumin when injected into an ameba or discharged into the solution about it raises the apparent pH of the cytoplasm of the ameba.

2. With time the cytoplasm returns to the original pH 6.9 if the nucleus is present. Amebae that have received repeated injections of albumin in some cases extrude their nuclei. In these cells the cytoplasm remains at the more alkaline pH induced by the albumin for at least 12 hours.

3. When a 2 per cent solution of albumin is introduced into a suspension of amebae there is a temporary marked rise in the rate at which CO2 is given off with no corresponding rise in O2 uptake.

4. The results observed can be explained if the albumin discharged onto the surface of the ameba rapidly enters the cell and there becomes distributed in a phase of the cytoplasm other than the one which contains the phenol red.
MUSCULAR ACTIVITY AND BUBBLE FORMATION IN ANIMALS DECOMPRESSED TO SIMULATED ALTITUDES
Authors: Whitaker D. M. , Blinks L. R. , Berg W. E. , Twitty V. C. , Harris Morgan
Published: May 2004

1. Muscular activity during decompression causes bubble formation in the blood of intact bullfrogs. The amount of gas liberated depends on the degrees of muscular activity and supersaturation (as influenced by altitude). In decompressed dissected bullfrogs, bubbles appear in veins leading from active but not from inactive muscles.

2. Muscular activity during decompression similarly causes bubble formation in rats. Bubbles appear in veins coming from muscles, and often in the lymphatic system. Quiescent rats do not form bubbles.

3. Violent muscular activity before decompression favors bubble formation in bullfrogs during ensuing decompression, but it is less effective than exercise during decompression. The effect persists in large frogs for about an hour.

4. Pre-oxygenation for 2 to 4 hours before decompression reduces the incidence of bubble formation in decompressed bullfrogs. It thus has the same effect on bubble formation in bullfrogs as it does on the "bends" in man. The effect is presumably due to removal of nitrogen.

5. Possible mechanisms by which muscular activity causes bubble formation are discussed. The effects of mechanical agitation and of metabolic CO2 are considered to be the dominant factors.
CARBON DIOXIDE AS A FACILITATING AGENT IN THE INITIATION AND GROWTH OF BUBBLES IN ANIMALS DECOMPRESSED TO SIMULATED ALTITUDES
Authors: Harris Morgan , Berg W. E. , Whitaker D. M. , Twitty V. C. , Blinks L. R.
Published: May 2004

1. Rats killed in a variety of ways (broken neck, nembutal, anoxia, electrocution) may undergo extensive bubble formation when subsequently decompressed from atmospheric pressure to simulated altitudes of 50,000 feet. On autopsy at sea level, large numbers of bubbles are found throughout the vascular system in the majority of animals. These bubbles appear to originate in small vessels deep within muscular regions, later spreading widely in arterial and venous systems. Dead rabbits and frogs also bubble profusely on decompression.

2. Bubble formation in dead animals is attributed primarily to the accumulation of CO2, derived from residual cellular respiration after death, and from anaerobic glycolysis with attendant decomposition of bicarbonates in blood and tissue fluids. If anaerobic glycolysis is inhibited by using sodium iodoacetate as a lethal agent, bubble formation is greatly reduced or lacking on subsequent decompression.

3. Experiments in vitro suggest that high concentrations of CO2 favor bubble formation by reducing the degree of mechanical disturbance necessary.

4. Administration of CO2 in high concentrations to living frogs lowers the minimum altitude (pressure equivalent) at which bubble formation occurs, with exercise, in untreated animals. Pre-treatment with CO2 also reduces the degree of muscular activity necessary for bubbles to form in frogs at higher altitudes.

5. Analyses have been made of the gas content of bubbles taken directly from the large veins of decompressed frogs and rats. In living animals the figures obtained indicate rapid equilibration with gas tensions in the blood. Bubbles taken from decompressed dead rats may contain 60–80 per cent CO2.

6. The bearing of these experiments on the mechanisms of bubble initiation and growth in normal living animals is discussed. Reasons are given for suggesting that CO2, due largely to its high dissolved concentration in localized active regions, may be an outstanding factor in the initiation and early growth of bubbles which in later stages are expanded and maintained principally by nitrogen.
ADDITIONAL MECHANISMS FOR THE ORIGIN OF BUBBLES IN ANIMALS DECOMPRESSED TO SIMULATED ALTITUDES
Authors: Berg W. E. , Harris Morgan , Whitaker D. M. , Twitty V. C.
Published: May 2004

1. A heavy ingestion of frothy emulsified fat by rats and bullfrogs does not increase susceptibility to bubble formation when the animals are decompressed 2 to 72 hours later. This indicates that gaseous films (bubble nuclei) initially present do not pass across the intestinal wall with the digested fat, and also that high fat content per se in the lymph and blood does not increase susceptibility to bubble formation.

2. Liquid caprylic acid injected into veins of bullfrogs crystallizes when the frogs are cooled. The crystallization causes bubbles to form without muscular activity on subsequent decompression. Cooling normal bullfrogs to 1–2°C. fails, however, to crystallize any substances occurring naturally in the animals that might act in a similar manner.

3. When bullfrogs are cooled (e.g. to –5° to –10°C.) until ice forms in the blood vessels, and are then warmed and decompressed, bubbles form in the absence of exercise. Crystallization of water in the body thus forms nuclei or even small bubbles that persist. If only one foot is frozen, bubbles originate in the frozen foot. In some cases visible bubbles were observed in thawed feet at sea level (i.e. without decompression). When frog's blood is partly frozen in test tubes or in tied off sections of veins, bubbles will appear on decompression in the absence of mechanical agitation. The practical relation of this phenomenon to flight at high altitude should not be overlooked.

4. Fracturing a leg bone (tibia or femur) in a frog induces bubble formation on subsequent decompression. Bubble nuclei, which persist for ½ to 1 hour, are probably formed as a result of the intense mechanical disturbance when the bone snaps. Fracturing of bone is considerably more effective than crushing muscles for producing bubbles in frogs.
o-PHENANTHROLINE AND DERIVATIVES OF VITAMIN K AS STABILIZERS OF PHOTOREDUCTION IN SCENEDESMUS
Authors: Gaffron H.
Published: May 2004

It is known that with increasing concentrations of hydroxylamine the rate of photoreduction in the alga Scenedesmus drops to about one-half of the normal rate. From then on photoreduction remains insensitive to hydroxylamine. The present experiments prove that this strange effect is not specific for hydroxylamine. It can be produced with substances having quite different chemical properties, such as o-phenanthroline, 2-methyl-1,4-naphthoquinone (vitamin K), or 2-oxy-3-methyl-naphthoquinone (phthiocol). Once the rate of photoreduction has been brought down to the limit of exactly one-half by a sufficient dose of any one of these substances, the reaction is also stabilized against reversion under the influence of strong light. At saturation intensities the rate of the stabilized photoreduction may be several times that at which the unpoisoned cells revert to photosynthesis. The ratio of one-half between the rates of the stabilized and the normal photoreduction is found at very low light intensities. This indicates a change in the photochemical process. Since the assimilatory quotient remains unaltered, it is the quantum yield which is cut in half under the influence of the poisons. To explain these observations it is assumed that either just one-half of the primary photoproducts are lost, or that they react back entirely while causing a reduction of carbon dioxide in a way similar to that brought about by the oxyhydrogen reaction in the dark.
STUDIES ON THE METABOLISM OF THE COLORLESS ALGA PROTOTHECA ZOPFII
Authors: Anderson Edward H.
Published: May 2004

The metabolism of Prototheca zopfii was investigated in an attempt to establish the specific function of its growth factor, thiamin. A study of the oxidative decomposition of various substrates by this organism demonstrated that the addition of catalytic amounts of thiamin to vitamin-deficient cells causes a pronounced stimulation in the rate of oxygen utilization during the degradation of certain compounds.

The phosphoric ester of thiamin is known to be the prosthetic group of carboxylase. The fact that this enzyme is involved in the decomposition of pyruvic acid suggested that this α-keto acid might be an important intermediate product in the metabolism of Prototheca. Pyruvic acid, however, was not included in the list of organic substances which Barker had reported as utilized by this alga. Barker's observations were confirmed, but subsequent experiments led to serious doubts as to the validity of his interpretation. Further investigations resulted in the establishment of environmental conditions which permit this alga to readily decompose pyruvic acid, as well as nearly all other organic acids tested. This can be accomplished by providing a millieu of sufficiently low pH to insure the presence of undissociated acid molecules.

The stimulatory effect on the rate of oxygen consumption, caused by the addition of minute amounts of thiamin to suspensions of vitamin-deficient cells of Prototheca respiring pyruvic acid, indicates that the presence of thiamin results in the synthesis of enzyme systems which are involved in the decomposition of pyruvic acid.

Experimental data on the oxidation of pyruvic acid and other organic compounds are discussed in the light of various hypotheses which have been advanced concerning the rôle of carboxylase in the decomposition of pyruvic acid. The conservative conclusion which can be drawn from the available information is that there appears to be no justification for a belief that thiamin and carboxylase are functional in biochemical reactions other than in decarboxylation and carboxylation processes.

The discovery of the ability of Prototheca to utilize substituted and dicarboxylic acids led to further studies on the mechanism of oxidative assimilation. The results of these investigations are in agreement with those of Clifton and Logan, and of Doudoroff, and indicate the existence of a relatively simple chemical mechanism of assimilation rather than of a strictly energetic coupling of catabolic and anabolic reactions.

A consideration of possible mechanisms for the oxidative assimilation of pyruvic and lactic acids indicates acetic acid as the most likely starting point for the assimilatory process proper.

Experimental investigations of the mode of acetate breakdown began with studies on the oxidation of glycolic acid. This substance is shown to be an oxidation catalyst in the metabolism of Prototheca zopfii. The exact nature of the catalytic function has not yet been determined.
DIFFERING RATES OF DEATH AT INNER AND OUTER SURFACES OF THE PROTOPLASM
Authors: Osterhout W. J. V.
Published: May 2004

The inner and outer protoplasmic surfaces in Nitella may differ greatly in behavior. When 0.01 M HgCl2 is applied externally death arrives first at the inner surface. But when 0.01 M HgCl2 + 0.01 M KCl is applied death takes place sooner at the outer surface. Since 0.01 M KCl by itself is not toxic its effect may be to condition the surface layer chemically or by means of the diffusion potential it sets up (this may amount to 100 mv.).

These surfaces consist of non-aqueous films forming the boundaries of a layer of aqueous protoplasm not over 10 microns in thickness.

These and earlier experiments with formaldehyde and with chloroform show clearly that it is possible to control the behavior of the protoplasmic surfaces so that when a toxic agent is applied it may produce death more rapidly at the inner or at the outer surface according to experimental conditions.
THE MECHANISM OF THE INHIBITION OF HEMOLYSIS
Authors: Ponder Eric
Published: May 2004

1. When digitonin is the lysin, the inhibitory power of sols of cholesterol and related substances depends primarily on a normal, as opposed to an epi, configuration of H and OH at C3. Subsidiary inhibitory effects depend on whether the double bond of cholesterol at C5 is saturated or not, and a trans hydrogen at C5 is associated with a greater inhibition than a cis hydrogen.

2. When saponin is the lysin, normal cholesterol is more inhibitory than its epimer. When the double bond at C5 is saturated (cholestanol, coprosterol, and their epimers), the epi configuration is more inhibitory than the normal configuration. This may be associated with the tendency of the epimers to form liquid interpenetrating films with films of digitonin and digitonin-like lysins.

3. At least one of the esters of cholesterol (cholesteryl acetate) has a small but definite inhibitory effect on both digitonin and saponin hemolysis.
A PROTEOLYTIC ENZYME OF SERUM: CHARACTERIZATION, ACTIVATION, AND REACTION WITH INHIBITORS
Authors: Christensen L. R. , MacLeod Colin M.
Published: May 2004

1. Fibrinolysin-activated lysin factor and chloroform-activated serum protease of serum and plasma are one and the same enzyme, differing only in their mode of activation.

2. The enzyme as it normally occurs in serum or plasma is not inactive because of combination with serum inhibitor. It is present as an inactive precursor or zymogen and may be activated from this state by streptococcal fibrinolysin.

3. The activation of serum protease by streptococcal fibrinolysin is a catalytic reaction, analogous to the kinase activation of trypsinogen by enterokinase. Treatment of serum or plasma with chloroform apparently results in removal of serum inhibitor which may allow autocatalytic activation of the serum protease.

4. The serum enzyme differs from trypsin in its pH of optimum activity, in its reactions with specific protease inhibitors, and in its action on casein.

5. A revised nomenclature for the serum enzyme system is suggested which more accurately describes its properties than the terms in current use.
STUDIES ON THE pH AND Eh OF NORMAL AND INFLUENZA-INFECTED EGGS
Authors:   By the Research Staff of United States Navy Medical Research Unit No. 1, Berkeley
Published: May 2004

1. pH values of allantoic fluids from non-infected eggs showed a rapid drop from the 12th to the 17th day of embryonic development. A definite age-pH relationship was shown to exist.

2. The allantoic fluid of eggs infected with influenza virus, contrasting with the non-infected eggs, revealed pH values which remained relatively stable about the neutral point at any age between 11 and 17 days. No relationship between pH and age could be established, in the infected series.

3. The Eh value of the fluid from non-infected eggs also exhibited a significant relationship to embryonic age. The majority of the determinations revealed a positive potential.

4. Similar determination on influenza-infected eggs gave results of a predominantly negative potential, indicating a marked state of reduction accompanying virus multiplication. As with the pH determinations, the Eh values of infected eggs were not a function of their age.
THE RHEOLOGY OF THE BLOOD. V
Authors: Bingham Eugene C.
Published: May 2004

A study has been made of those proteins which might offer exceptions to the law that the fluidity of a protein solution is a linear function of the volume concentration; viz., egg albumin, serum albumin, pseudoglobulin, euglobulin, gelatin, and sodium caseinogenate.

Solutions of egg albumin below 20 per cent by weight obey the above law but somewhat below 30 per cent the fluidities begin to be too high, presumably due to the contribution to the fluidity made by the deformation of the particles as they come into contact, as the fluidity approaches zero.

The fluidity of serum albumin solutions shows a similar behavior, being exceptional above 15 per cent in weight. Pseudoglobulin and euglobulin give fluidity-concentration curves (Fig. 4) which are linear up to about 2.5 per cent each in a total range of 20 and 14 per cent respectively. From this singular point both compounds show a second range which is linear. Pseudoglobulin is the only substance whose solutions seem to show a third linear range. We have also used the data of Chick and Martin for sodium caseinogenate and found evidence for two linear régimes.

It is desirable at this time to call attention to the measurements of the flow of glycogen solutions by Botazzi and d'Errico (14) which in Fluidity and

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plasticity, page 207, are expressed in rhes. The data show two linear fluidity curves of different slopes. In this case it was definitely known that the data for each curve were measured with different viscometers which suggested the possibility of an error in viscometry entering in to confuse the issue. We have no suspicions as to the reliability of the data studied in this paper; we only wish to caution the readers that our hypotheses based on these data must be regarded with due reserve until confirmed.

We have found a formula (11) based on the supposed linear relation between logarithmic fluidities and concentration which is convenient to use within the range, but close examination reveals that it does not reproduce the data for the higher concentrations at 25° nor does it permit extrapolation to pure water It is not realistic enough because it does not contemplate any change of régime in going from viscous to non-Newtonian or plastic flow. The formula does not apply to any other of the proteins studied in this paper nor to the great majority of proteins already reported as following the linear law. These are serious objections. We have therefore offered as an alternative a simple formula (24) according to which the fluidities are additive in the viscous régime. When the emulsoid particles approach close packing, they are deformed and this deformation contributes to the flow and the fluidity volume concentration curve is again linear. In fact, there may be one or more additional changes of régime.