bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
THE TOXICITY OF COPPER NITRATE SOLUTIONS TO POLYCELIS NIGRA
Authors: White Theodore 
Published: May 2004

The estimation of the number of variables operating in cases of toxic action toward living organisms is discussed. The toxicity of glucose, sodium chloride, and copper nitrate solutions to Polycelis nigra has been investigated and also that of copper nitrate solutions whose osmotic pressure was adjusted to a constant level by the addition of glucose or of sodium chloride.
It is shown that hypertonic solutions of copper nitrate are abnormally toxic but that the osmotic variable is not the factor responsible for this abnormally high toxicity. The lack of data which might elucidate such problems is indicated.
During the course of this work it was observed that mixed solutions of copper nitrate + sodium chloride and copper nitrate + glucose exhibit toxicities greater than those expected from consideration of the separate toxicities of the components of the mixtures.
THE ACCELERATION OF SAPONIN HEMOLYSIS BY PROFLAVINE
Authors: Collier H. Bruce 
Published: May 2004

Proflavine is a very powerful accelerator of saponin hemolysis of rabbit, human, and dog erythrocytes. Lysolecithin hemolysis, on the other hand, is inhibited.
Dog erythrocytes in the presence of proflavine undergo marked changes in shape, finally becoming rods of about 13 µ in length. Rabbit and human erythrocytes are not altered in form under these conditions.
THE EFFECTS OF CAFFEINE ON OXYGEN CONSUMPTION AND CELL DIVISION IN THE FERTILIZED EGG OF THE SEA URCHIN, ARBACIA PUNCTULATA
Authors: Cheney Ralph Holt 
Published: May 2004

1. By means of the Warburg-Barcroft microrespirometer apparatus and the Warburg direct method, the relative effect of caffeine upon the O2 consumption of the fertilized egg of Arbacia punctulata was shown for the following concentrations in sea water: 0.002 per cent (M/10,000), 0.004 per cent (M/5,000), 0.02 per cent (M/1,000), 0.1 per cent (M/200), 0.2 per cent (M/100), 0.5 per cent (M/40), and 2 per cent (M/10).
2. In comparison with the normal eggs (uninhibited, non-caffeine-treated controls), caffeine in concentrations including and greater than 0.1 per cent (M/200) depressed the average uptake from approximately 25 to 61 per cent over the 3 hour period. In a number of instances, as typified by Experiment 10, the effective inhibitory concentration ranged from 0.02 per cent (M/1,000) upward and the degree of depression of the O2 consumption ranged from 10.6 per cent to 60.6 per cent.
3. All caffeine concentrations including and above 0.02 per cent (M/1,000) in the series used, resulted in decreasing the normal rate of cleavage division in the fertilized Arbacia eggs.
4. The higher concentrations (0.5 and 2 per cent) produced a complete blockage of the cleavage process.
5. Complete cleavage inhibition was noted only when the O2 uptake had been depressed to 50 per cent or more of the normal controls.
6. O2 consumption-time relationship data indicate an average depression, in O2 consumption over a 3 hour period, ranging from 25 per cent with a caffeine concentration of 0.1 per cent to a 61 per cent inhibition with a concentration of 2 per cent.
7. Concentrations of less than 0.1 per cent (certainly of less than 0.02 per cent) give variable results and indicate no significant effect.
8. It is inferred from the respiration data presented that it is probable that the inhibition of the O2 consumption in fertilized Arbacia eggs is due to the influence of caffeine upon the main (activity or primary) pathway. It will be observed that there are certain similarities of the caffeine data to the degree of inhibition accomplished by sodium cyanide. Moreover, it has been demonstrated that the cyanide probably acts on the cytochrome oxidase step in the cytochrome oxidase-cytochrome chain of reactions constituting the O2 uptake phase of respiratory metabolism. It is not improbable, therefore, that caffeine also may act upon the cytochrome oxidase enzyme.
9. From the viewpoint of environmental conditions influencing reproductive phenomena, it is of interest that caffeine can affect the normal metabolism of the zygote.
WATER RELATIONS IN THE CELL
Authors: Osterhout W. J. V. 
Published: May 2004

Chloroplasts may contract under natural conditions and give up water to the rest of the cell, thus indicating changes in metabolism or constitution. Such contractions may be produced experimentally.
In Nitella the chloroplasts are ellipsoid bodies which, under natural conditions, may contract to spheres with a loss of volume. This may be brought about by lead acetate, ferric chloride, and digitonin: the contraction may occur while the cell is alive. The contraction in lead acetate is reversible (in lead nitrate little or no contraction occurs).
In Spirogyra the chloroplast is a long, spirally coiled ribbon which may contract under natural conditions to a short nearly straight rod with a loss of volume. This can be brought about by inorganic salts and in other ways while the cell is still alive.
THE ACTION SPECTRUM OF SENSITIZATION TO HEAT WITH ULTRAVIOLET LIGHT
Authors: Giese Arthur C. , Crossman Elizabeth B. 
Published: May 2004

1. Heat does not sensitize paramecia to ultraviolet light but ultraviolet light sensitizes them to heat. Paramecia of two species (Paramecium caudatum and P. multimicronucleate) are much more readily killed by heat at 42.3° C. if they are first exposed to ultraviolet light.
2. From studies on paramecia irradiated with a given dosage at various wave lengths before being killed by heat, an action spectrum of the compound in the protoplasm being sensitized to heat can be determined. Proteins with absorption similar to that of pseudoglobulin are suggested by these experiments.
3. The effect upon living things differs from that on pure protein systems in that paramecia are not rendered more sensitive to temperatures below the lethal temperature whereas proteins are.
4. Almost complete recovery from ultraviolet light as judged by heat sensitivity occurs within 4 to 5 days.
5. By a study of the rate of recovery from doses at different wave lengths evidence suggesting effects on nucleic acid is obtained.
6. The possible significance of the data and the action spectrum is discussed.
PURIFICATION AND PROPERTIES OF DESOXYRIBONUCLEASE ISOLATED FROM BEEF PANCREAS
Authors: McCarty Maclyn 
Published: May 2004

1. A method is described for the isolation and purification of desoxyribonuclease from a 0.25 N sulfuric acid extract of beef pancreas. The activity of the enzyme is measured by a viscosimetric method using sodium desoxyribonucleate from calf thymus as substrate.
2. The enzyme is highly active, a measurable effect being obtained at concentrations of less than 0.01 microgram per cc. In highly dilute solution the enzyme is rapidly inactivated, and the use of a protective agent such as gelatin or peptone is necessary.
3. The purified material contains traces of a proteolytic enzyme, but displays no ribonuclease, lipase, or phosphatase activity.
4. The enzyme requires activation by magnesium or manganese ion, and citrate serves as a potent inhibitor of the magnesium-activated enzyme.
5. Its enzymatic activity is inhibited by the specific antibody present in the serum of rabbits immunized with enzyme protein.
THE EFFECTIVENESS OF THE SPECTRUM IN CHLOROPHYLL FORMATION
Authors: Frank Sylvia R. 
Published: May 2004

1. Although the carotenoid pigments are present in large concentration in the plastids of etiolated Avena seedlings as compared with protochlorophyll, the pigment precursor of chlorophyll, it is possible to show that the carotenoids do not act as filters of the light incident on the plant in the blue region of the spectrum where they absorb heavily. This suggests that the carotenoids are located behind the protochlorophyll molecules in the plastids.
2. Since the carotenoids do not screen and light is necessary for chlorophyll formation, an effectiveness spectrum of protochlorophyll can be obtained which is the reciprocal of the light energy necessary to produce a constant amount of chlorophyll with different wavelengths. The relative effectiveness of sixteen spectral regions in forming chlorophyll was determined.
3. From the effectiveness spectrum, one can conclude that protochlorophyll is a blue-green pigment with major peaks of absorption at 445 mµ, and 645 mµ, and with smaller peaks at 575 and 545 mµ. The blue peak is sharp, narrow, and high, the red peak being broader and shorter. This differs from previous findings where the use of rougher methods indicated that red light was more effective than blue and did not give the position of the peaks of absorption or their relative heights.
4. The protochlorophyll curve is similar to but not identical with chlorophyll. The ratio of the peaks of absorption in the blue as compared to the red is very similar to chlorophyll a, but the position of the peaks resembles chlorophyll b.
5. There is an excellent correspondence between the absorption properties of this "active" protochlorophyll and what is known of the absorption of a chemically known pigment studied in impure extracts of seed coats of the Cucurbitaceae. Conclusive proof of the identity of the two substances awaits chemical purification, but the evidence here favors the view that the pumpkin seed substance, which is chemically chlorophyll a minus two hydrogens, is identical with the precursor of chlorophyll formation found in etiolated plants.
SENSITIZATION OF CELLS TO HEAT BY VISIBLE LIGHT IN PRESENCE OF PHOTODYNAMIC DYES
Authors: Giese Arthur C. , Crossman Elizabeth B. 
Published: May 2004

1. Visible light of high intensity does not injure paramecia or sensitize them to heat.
2. If photodynamic dyes are added, paramecia are readily killed by visible light of high intensity and are sensitized to heat by sublethal dosages of light.
3. Cells so sensitized are killed when subjected to a sublethal exposure to heat.
4. If the light and heat are applied in the reverse order, namely, heat and then light, no ill effects are observed.
5. When the concentration of dye is reduced a larger light dosage is required.
6. Recovery from sensitization is slow, requiring about 4 days for a ¾ lethal dosage.
7. Sublethal dosages of light in the presence of dyes do not affect the division rate even when ¾ the lethal dosage has been used.
8. A possible explanation for the photodynamic sensitization to heat is discussed.
NERVE AS MODEL TEMPERATURE END ORGAN
Authors: Bernhard C. G. , Granit Ragnar 
Published: May 2004

Rapid local cooling of mammalian nerve sets up a discharge which is preceded by a local temperature potential, the cooled region being electronegative relative to a normal portion of the nerve.
Heating the nerve locally above its normal temperature similarly makes the heated region electronegative relative to a region at normal temperature, and again a discharge is set up from the heated region.
These local temperature potentials, set up by the nerve itself, are held to serve as "generator potentials" and the mechanism found is regarded as the prototype for temperature end organs.
THE EXTRACELLULAR RELEASE OF ECHINOCHROME
Authors: Shapiro Herbert 
Published: May 2004

A study was made of the diffusion of the red pigment echinochrome from the eggs of the sea urchin, Arbacia punctulata, into sea water.
Unfertilized eggs retained their pigment, over periods of hours. Outward diffusion of pigment from unfertilized eggs normally is entirely negligible, or does not occur at all. Enchancing the calcium or potassium content of the artificial sea water (while retaining isosmotic conditions) did not induce pigment release.
Under anaerobic conditions, unfertilized eggs release pigment in small quantities.
Fertilization alone brings about echinochrome release. Fertilized eggs invariably released pigment, whether in normal sea water, or sea water with increased calcium or potassium. This diffusion of the pigment began during the first cleavage, possibly soon after fertilization.
The pigment release is not a consequence solely of the cell's permeability to echinochrome (or chromoprotein, or other pigment combination) but is preceded by events leading to a release of echinochrome from the granules in which it is concentrated within the cell. These events may be initiated by activation or by anaerobiosis.
The phenomenon was not due to cytolysis.
PHOTOLYTIC LIPIDS FROM VISUAL PIGMENTS
Authors: Bliss Alfred Frederick 
Published: May 2004

A method is described for the preservation of iodopsin, the labile photopigment of daylight vision, by freeze drying in vacuo.
The lipids released by the action of light on rhodopsin and iodopsin are found to be similar and to possess a labile absorption spectrum in chloroform, with a rising peak at about 390 mµ and a declining peak in the region of 470 mµ. After the change is complete the absorption spectrum resembles closely that of retinene.
ISOLATION OF HEXOKINASE FROM BAKER'S YEAST
Authors: Berger Louis , Slein Milton W. , Colowick Sidney P. , Cori Carl F. 
Published: May 2004

1. A method is described for the isolation of hexokinase from baker's yeast. The method is based mainly on fractionation with alcohol and results
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in a 30-fold increase in specific activity. The final product could be crystallized from ammonium sulfate without change in specific activity.
2. The enzyme catalyzes a transfer of phosphate from adenosinetriphosphate to glucose, fructose, or mannose, the relative rates with these three sugars being 1:1.4:0.3.
3. With glucose as substrate, the turnover number for the crystalline enzyme is 13,000 moles of substrate per 105 gm. of protein per minute at 30° and pH 7.5. The temperature coefficient (Q10°) between 0 and 30° is 1.9.
4. Magnesium ions are necessary for the activity, the dissociation constant for the Mg++ -protein complex being 2.6 x 10–3. Fluoride in concentrations as high as 0.125 M has no inhibitory effect on the enzyme when the Mg++ and orthophosphate concentrations are 6.5 x 10–3 M and 1 x 10–3 M, respectively.
5. The crystalline enzyme shows a loss in activity when highly diluted. This loss in activity can be prevented by diluting in the presence of small amounts of other proteins. Of the various protective proteins tested, insulin was the most effective, providing complete protection in a concentration of 6 micrograms per cc.; with serum albumin, a concentration of 60 micrograms per cc. was necessary. Thiol compounds (cysteine, glutathione) exerted no protective action.
6. The inactivation of the crystalline enzyme on incubation with trypsin can be prevented to a marked degree by the presence of glucose. The instability of crude preparations of yeast hexokinase may be attributed to the presence of proteolytic enzymes, since glucose or fructose has a remarkable protective effect on such preparations.
CULTURE CONDITIONS AND THE DEVELOPMENT OF THE PHOTOSYNTHETIC MECHANISM
Authors: Myers Jack ,   With the Technical Assistance of James Johnston and Helen Davis
Published: May 2004

1. Chlorella pyrenoidosa has been grown in a continuous-culture apparatus under various light intensities provided by incandescent lamps, other conditions of culture being maintained constant. The harvested cells were analyzed for cell number, dry weight, nitrogen, and chlorophyll per unit cell volume.
2. Cell nitrogen and cell volume are parallel measures of cellular material over the range of light intensity studied.
3. The dry weight per cell volume increases slowly with light intensity, showing about a 20 per cent variation.
4. Chlorophyll concentration and cell number show a concomitant decrease with increasing light intensity, varying in such a way that there are always about the same number of chlorophyll molecules per cell. It is considered that this phenomenon has bearing on the interpretation of data which has led to the theory of the photosynthetic unit.