bluuebunny/crossref_metadata_2025_split huggingface dataset:
PROTEIN COAGULATION AND ITS REVERSAL
Authors: Anson M. L. , Mirsky A. E. 
Published: May 2004

1. By a procedure involving the use of acid acetone hemoglobin may be rapidly separated into a precipitate of denatured globin and an acetone solution of heme.
2. By neutralization procedures the denatured globin may be largely converted into a soluble, apparently native form which can combine with heme to form hemoglobin.
3. The heme may be obtained in acetone-free, slightly alkaline solution without the use of strong alkali which may modify the heme.
THE EFFECT OF ISOELECTRIC AMINO ACIDS ON THE pH+ OF A PHOSPHATE BUFFER SOLUTION
Authors: Borsook Henry , MacFadyen Douglas A. 
Published: May 2004

The relative merits of the classical conception and of the Zwitter Ion conception of the dissociation of amphoteric electrolytes are discussed, and the following data are presented which confirm the Zwitter Ion hypothesis of Bjerrum, and which are not in accord with the classical view.
1. Amino acids in the isoelectric form resemble strong electrolytes in that they contribute to the ionic strength of the solution.
2. The dielectric constants of aqueous solutions of amino acids, like those of solutions of strong electrolytes greater than 0.02 normal, are considerably greater than that of pure water.
3. The magnitude of the dissociation constants of substituted acetic acids and of glycine, are more easily accounted for with the Zwitter Ion than with the classical conception.
THE ENZYMIC HYDROLYSIS OF PHLORIDZIN
Authors: Moelwyn-Hughes E. A. 
Published: May 2004

1. Considering previously published data on the velocity of hydrolysis of glucosides by acids, it is shown that phloridzin, judged from the standpoint of the velocity coefficient and the critical increment for hydrolysis, resembles the γ-fructosides (sucrose, raffinose and melezitose) more closely than it does the normal glucosides (salicin, arbutin, maltose, etc.).
2. Previous work on the enzymic hydrolysis of phloridzin shows that it is not hydrolysed by emulsin, but that it is hydrolysed by some other enzyme which occurs fairly freely in nature.
3. The difficulty in examining the enzymic hydrolysis of phloridzin lies in its very low solubility. It has been shown, in confirmation of earlier work, that emulsin is definitely without action on phloridzin at various values of pH and of temperature. This result is difficult to reconcile with the ß-glucosidic character commonly ascribed to phloridzin, and with the fact that emulsin hydrolyses (synthetic) phloroglucinol-ß-glucoside, of which phlorizin is regarded as a derivative.
4. Phloridzin is hydrolysed by a yeast maltase preparation, known to contain saccharase. Phloridzin is readily attacked by maltase-free saccharase at 30°C. and pH of 4.45. If the α-glucase of the sucrose-splitting enzyme is (as stated) inactive under these conditions, then the enzyme responsible for the hydrolysis of phloridzin is ß-(γ) fructosidase.
5. The sugar prepared from phloridzin differs from glucose in its specific rotation and in its action towards Bacillus pestis.
THE VARIATION OF ELECTRICAL RESISTANCE WITH APPLIED POTENTIAL
Authors: Blinks L. R. 
Published: May 2004

The resistance of very thin collodion membranes to direct current bears some resemblance to that of living cells since it varies with the applied potential. With membranes separating two different solutions the resistance varies with the direction (and the voltage) of the applied potential, rising when less mobile ions are carried across the membrane and falling when more mobile ones are so carried. (With some membranes the resistance varies with potential when the same solution is on both sides.) These changes are very prompt and regular. There is a hysteretic effect of previous current flow.
But the membranes differ from Valonia cells in that the rise of resistance is largely ohmic, there being little or no polarization potential.
A STUDY OF THE BACTERICIDAL ACTION OF ULTRA VIOLET LIGHT
Authors: Gates Frederick L. 
Published: May 2004

The simple conclusion of former investigators that the shorter the wave length of ultra violet light the greater the bactericidal action is in error. A study with measured monochromatic energy reveals a characteristic curve of bactericidal effectiveness with a striking maximum between 260 and 270 m.µ. The reciprocal of this abiotic energy curve suggests its close relation to specific light absorption by some single essential substance in the cell.
Methods are described for determining the absorption curve, or absorption coefficients, of intact bacteria. These curves for S. aureus and B. coli have important points of similarity and of difference with the reciprocals of the curves of bactericidal incident energy, and point the way in a further search for the specific substance, or substances, involved in the lethal reaction.
THE OSMOTIC PROPERTIES OF LIVING CELLS (EGGS OF ARBACIA PUNCTULATA)
Authors: McCutcheon Morton , Lucké Balduin , Hartline H. Keffer 
Published: May 2004

We have attempted to answer the question: How nearly ideal, as an osmometer, is the unfertilized Arbacia egg? The following conclusion have been reached:
1. Volumes can be measured accurately over a wide range of pressures since the cell is in general spherical and does not suffer deformation from its own weight or other factors.
2. The product of volume and pressure is approximately constant, if allowance be made for osmotically inactive cell contents. It is computed that from 7 to 14 per cent of cell volume is occupied by osmotically inactive material.
3. Evidence is presented that no appreciable escape of cell contents occurs while the cell is in hypotonic sea water; that, therefore, the semipermeability of the membrane is approximately perfect, so long as injury to the cell is avoided.
4. In comparison with osmotic pressure the influence of other forces, such as elasticity or surface tension, on cell volume must in these experiments be slight.
PROTEIN COAGULATION AND ITS REVERSAL
Authors: Anson M. L. , Mirsky A. E. 
Published: May 2004

1. Methemoglobin prepared from coagulated hemoglobin by the reversal of coagulation has the same solubility within 2 per cent as normal methemoglobin.
2. Methemoglobin synthesized from hemin and the native globin prepared by the reversal of coagulation of globin likewise has the same solubility as normal methemoglobin.
THE VAPOUR PRESSURES OF AQUEOUS SOLUTIONS WITH SPECIAL REFERENCE TO THE PROBLEM OF THE STATE OF WATER IN BIOLOGICAL FLUIDS
Authors: Grollman Arthur 
Published: May 2004

Data for the depression of vapour pressure are presented for the following aqueous solutions: NaCl (0.03 to 0.1 molar), KCl (0.03 to 0.1 molar), urea (0.05 to 0.5 molar), sucrose (0.05 to 0.10 molar), lactic and succinic acids, creatine, CaCl2 (0.05 molar), and mixtures of these substances with one another and with certain other solutions (gelatin, gum acacia, sea water, LiCl, etc.). The relation of the depression of vapour pressure of a mixed solution to that of solutions of the individual constituents was investigated in order to ascertain to what extent such studies may be used for the determination of the degree of hydration, or of the state of water, in solutions. Organic substances (urea, sucrose, etc.) showed anomalous results which were markedly affected and unpredictable in mixed solutions. They are, therefore, unsuited for the study of water binding. In the case of solutions of inorganic substances—LiCl and CaCl2—the principle of the additive nature of colligative properties is also only approximately true—except perhaps in very dilute solutions. The limitations of the colligative method for determining the degree of hydration have been defined in accord with the above findings.
Studies of the vapour pressures of mixtures of gelatin or gum acacia with NaCl or KCl demonstrated that hydration in gelatin is relatively small at pH = 7 and undetectable in gum acacia solutions. The view, therefore, that hydrophilic colloids are strongly hydrated has not been substantiated. The passage from the sol to the gel state also was not accompanied in gelatin or in blood by any appreciable change in the degree of hydration of the hydrophilic colloids present in these substances.
THE INSENSITIVITY OF PARAMECIUM TO CYANIDE AND EFFECTS OF IRON ON RESPIRATION
Authors: Shoup Charles S. , Boykin James T. 
Published: May 2004

1. The effects of KCN and iron salts on oxygen consumption has been studied in the cell of Paramecium caudatum by manometric methods.
2. KCN solutions of strengths from M/200 to M/10,000 have been shown to produce no decrease in oxygen consumption, but have in most cases produced a very slight increase in the respiration rate.
3. The pH values were found to have little or no effect on these results.
4. Iron salts produce either no effect or a great diminution of oxygen consumption, in no case causing stimulation of rates of respiration.
5. Iron salts in neutral solutions do not penetrate the Paramecium cell nor do they cause so marked an effect as in an acid state.
6. The iron-content of Paramecium was found to be extremely small and not demonstrable by delicate tests. It is believed that iron is not combined in the cell in the form of a respiration-catalyst sensitive to cyanide.
THE RÔLE OF PHOSPHATE IN BIOLOGICAL OXIDATIONS
Authors: Barmore Mark , Luck James Murray 
Published: May 2004

1. The effect of phosphate on the oxidation of glyceric aldehyde by methylene blue, 1-naphthol 2-sulfonate indophenol, and phenol-indophenol has been studied.
2. At pH 4.77 in a phthalate-buffered medium phosphate does not catalyze the reaction.
3. At pH 7.9 in solutions buffered with borate, carbonate, or phenylalanine marked catalysis by phosphate is observed. The effect is most pronounced in borate.
4. Phosphate catalysis, within the limits studied, is strictly a linear function of the phosphate concentration.
5. The high concentration of HPO4= and the low concentration of PO4≡ relative to that of the substrate virtually demand the conclusion that the PO4≡ ion is the active catalytic species.
HIGH SPEED PHOTOMICROGRAPHY OF LIVING CELLS SUBJECTED TO SUPERSONIC VIBRATIONS
Authors: Harvey E. Newton , Loomis Alfred L. 
Published: May 2004

A new type of camera system is described capable of taking 1200 pictures a second through a microscope objective.
Photographs showing the destruction of Arbacia eggs by high frequency sound waves indicate that the disintegration occurs in less than 1/1200 second.
Eggs drawn out into spindle or tadpole shapes suggest that rapid movements of the fluid tearing the eggs may be responsible for the disintegration. Although no cavitated air bubbles show in the photographs, other experiments make it likely that the rapid fluid movement is the result of submicroscopic cavitation.
ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. III
Authors: Crozier W. J. , Pincus G. 
Published: May 2004

Extension of analysis of the functional basis of geotropic excitation and response in young rats has made it desirable to obtain, for additional genetically stabilized lines, further tests of the quantitative reproducibility of orientation data as secured from successive generations in these lines over a period of several years; and of the measures of variation of performance as these are related to the exciting vector and to the extent of orientation. Procedures are illustrated whereby the significance of measurements can be checked automatically. It is shown that differences apparent in the geotropic behavior of three inbred lines of R. norvegicus are quantitatively recoverable over a period of nine generations. The constant, characteristic features for each inbred line concern: the extent of upward orientation, absolutely and as a function of the inclination of the substratum; the threshold slope for orientation; the dispersion of mean orientation-angles as governed by the slope of substratum; the dependence of the dispersion of the relative variation of observed orientation-angles upon the intensity of excitation; and the proportion of the total variation of response which is modifiable as a function of the slope of surface.
It is also shown that when for two lines of rats the curves connecting orientation-angle with inclination of substratum differ in position and in details of form, the curves none-the-less undergo distortions of homologous type when rats of these lines creep geotropically with the same additional load in the form of a mass attached at a corresponding position on the back; and that shifting this mass to another position induces a quite different modification of the curve.
These effects are discussed in terms of the view that orientation during geotropic creeping is controlled by the adjustment of sensorially equivalent tension-excitation in the legs of the two sides of the body, and that the frequency distributions of thresholds for excitation within the several groups of receptor units concerned differ quantitatively among the inbred stocks, but are statistically constant within each line.
THE COMBINING WEIGHT OF GELATIN AS AN ACID
Authors: Ferguson A. L. , Schluchter A. W. 
Published: May 2004

1. The nature of the reaction between gelatin and sodium hydroxide has been studied at three concentrations of gelatin.
2. Gelatin appears to react stoichiometrically with sodium hydroxide.
3. The addition of gelatin to sodium hydroxide does not change the concentration of sodium ions in the solution.
4. A given amount of gelatin reacts with the same amount of sodium hydroxide no matter what the concentration of sodium hydroxide or ratio of sodium hydroxide to gelatin, provided there is sufficient excess of sodium hydroxide to prevent hydrolysis.
5. The combining weight of dry gelatin as an acid is found to be 1370 gm.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G. , Osterhout W. J. V. 
Published: May 2004

Lowering the potassium in the sea water from 0.011 M to 0.006 M caused an exit of potassium from cells of Valonia macrophysa. Sodium continued to penetrate and the ratio K ÷ Na fell off. The cells ceased to grow but there was no evidence of injury.
Increasing the external potassium brought about an increase of the internal concentration of potassium, of halide, of total cations, and of the ratio K ÷ Na inside.
These phenomena are to be expected on theoretical grounds.
STIMULATION BY THE SALTS OF THE NORMAL ALIPHATIC ACIDS IN THE ROCK BARNACLE BALANUS BALANOIDES
Authors: Cole William H. 
Published: May 2004

1. Stimulation in the rock barnacle Balanus balanoides by the sodium salts of the first seven normal aliphatic acids has been studied at several different concentrations for each salt. The pH was adjusted to that of sea water (8.1 ±0.15) and all experimental conditions were held as constant as possible. Criterion of response was the per cent closure of valves at successive 2 minute intervals.
2. In general, the stimulating efficiency increases with concentration, but the ratios of effectiveness at increasing concentrations differ for each salt.
3. The order of effectiveness for 40 to 50 per cent closure is: heptylate = caproate &gt; valerate &gt; butyrate &gt; formate &gt; propionate &gt; acetate. For 60 per cent closure or more, formate is the least effective of all.
4. Stimulating efficiency is correlated with the potential of the anion of the acid and with the concentration of that ion near or at the receptor surface as determined by the length of the carbon chain.
ON THE INTENSITY-TIME RELATIONS FOR STIMULATION BY ELECTRIC CURRENTS. II
Authors: Blair H. A. 
Published: May 2004

Hypotheses previously used (Blair, 1932) in deriving formulae for stimulation by direct currents are applied to other forms of electrical stimuli. This consists in considering solutions of the equation
See PDF for Structure.
where p is assumed to represent the local excitatory process, V is the voltage of the stimulus and K and k are constants. The solutions are discussed in regard to condenser discharges, linearly rising currents, exponentially rising currents, and alternating currents. New experimental work with alternating currents of frequencies above 400 per second on the sciatic gastrocnemius of the frog is related to the formulae.
OSMOTIC RELATIONSHIPS IN THE HEN'S EGG, AS DETERMINED BY COLLIGATIVE PROPERTIES OF YOLK AND WHITE
Authors: Howard Evelyn 
Published: May 2004

The osmotic pressure of the yolk and white of the hen's egg have been shown to be identical, by means of direct freezing point determinations, dialyses, and vapor pressure measurements.
Dialysates of egg yolk slow the rate of ice formation compared with NaCl solutions. They also show a marked change of freezing rate as the freezing point is approached. The anomalous freezing behavior of this material may lead to errors in the determination of the true freezing point which would tend to make the value for the yolk erroneously low.
The postulate of a vital activity at the yolk membrane maintaining an osmotic pressure difference is thus shown to be unnecessary, since a simple osmotic equilibrium exists between the yolk and the white.
DARK ADAPTATION AND THE DARK GROWTH RESPONSE OF PHYCOMYCES
Authors: Castle E. S. 
Published: May 2004

Light-adapted sporangiophores of the fungus Phycomyces respond to sudden darkening by a temporary decrease in the rate of elongation, after a latent period of several minutes. The reaction time of this "dark growth" response is compound like that of the "light growth" response. It is, moreover, shorter the more intense the previous illumination.
The rate of dark adaptation following adaptation to a very large range of light intensities is found to be proportional to the logarithm of the preceding light intensity. It is shown that a constant amount of dark adaptation takes place before the response occurs.
On the assumption that changes in the rate of growth reflect changes in the concentration of a substance which at constant light intensity is in equilibrium with a light-sensitive material, possible equations for such a photostationary state are examined. The most reasonable formulation requires that the partial velocity of the "light" reaction be taken proportional to log I instead of to I directly.
CRYSTALLINE TRYPSIN
Authors: Northrop John H. , Kunitz M. 
Published: May 2004

A method is described for isolating a crystalline protein of high tryptic activity from beef pancreas. The protein has constant proteolytic activity and optical activity under various conditions and no indication of further fractionation could be obtained. The loss in activity corresponds to the decrease in native protein when the protein is denatured by heat, digested by pepsin, or hydrolyzed in dilute alkali.
The enzyme digests casein, gelatin, edestin, and denatured hemoglobin, but not native hemoglobin. It accelerates the coagulation of blood but has little effect on the clotting of milk. It digests peptone prepared by the action of pepsin on casein, edestin or gelatin.
The extent of the digestion of gelatin caused by this enzyme is the same as that caused by crystalline pepsin and is approximately equivalent to tripling the number of carboxyl groups present in the solution.
The activity of the preparation is not increased by enterokinase.
The molecular weight by osmotic pressure measure is about 34,000.
The diffusion coefficient in ½ saturated magnesium sulfate at 6°C. is 0.020 ±0.001 cm.2 per day, corresponding to a molecular radius of 2.6 x 10–7 cm.
The isoelectric point is probably between pH 7.0 and pH 8.0.
The optimum pH for the digestion of casein is from 8.0–9.0.
The optimum stability is at pH 1.8.
PHOTOKINESIS AND TONIC EFFECT OF LIGHT IN UNIONICOLA
Authors: Welsh John H. 
Published: May 2004

1. The speed of progression of Unionicola, a water mite, is influenced by light; and over a certain range increases as a function of the light intensity.
2. The relation between speed and light intensity is not a simple one, as the speed of progression is due to the combined effect of amplitude of steps and frequency of leg movement.
3. The amplitude of stride increases in direct proportion to the logarithm of the light intensity, while the frequency of stepping has no such simple relation to intensity.
4. The change in length of stride with changing light intensity indicates a tonic effect of light on the locomotor muscles. Such an effect has been observed previously in studies of orientation, due to unequal illumination, which produces changes in posture.
THE DISTRIBUTION OF THE ACTION CURRENTS PRODUCED BY HEART MUSCLE AND OTHER EXCITABLE TISSUES IMMERSED IN EXTENSIVE CONDUCTING MEDIA
Authors: Wilson F. N. , Macleod A. G. , Barker P. S. 
Published: May 2004

The action currents produced by heart muscle and other tissues immersed in or in contact with a large body of conducting material are distributed in accordance with the laws that govern the flow of electric currents in volume conductors.
The curve obtained when one electrode (the exploring electrode) is placed very close to and the other (the indifferent electrode) very far from the active tissue may be regarded as representing the potential variations of the exploring electrode alone; the. potential of the indifferent electrode is by comparison nearly constant.
Curves obtained by this method of leading from the surface of the mammalian auricle indicate that the electrical effects produced by the passage of the excitation wave along a single muscle fiber are nearly the same as those that would occur if the crest of this wave were immediately preceded by a source and followed by a sink.
A study of the electric field of a polarized membrane immersed in a volume conductor shows that this conclusion may be derived on theoretical grounds from the membrane theory of Bernstein.
SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. III
Authors: Nelson J. M. , Wilkes B. G. 
Published: May 2004

1. The relationship of sucrose and water concentration to invertase activity in vivo and in vitro has been studied under the same environmental conditions.
2. The sucroclastic activity of S. cerevisiae cells and of invertase solutions prepared from them reacts to changes in sucrose and water concentration in an identical manner.
3. The invertase contained in living yeast cells is just as freely exposed to the conditions of sucrose and water concentrations of the suspending medium as it would be if it were contained in a cell-free solution. Weight is added to the previous suggestion (2) that yeast invertase exerts its physiological activity in a region quite close to the surface of the cell.
AN EXPERIMENTAL COMPARISON OF DIFFERENT CRITERIA OF DEATH IN YEAST
Authors: Rahn Otto , Barnes Margaret Noble 
Published: May 2004

Different criteria of death have been compared experimentally and quantitatively. Pure cultures of a yeast have been subjected to adverse conditions, and the number of dead cells, judged by different tests, has been determined in successive time intervals. The yeast cultures were exposed to heat, to HgCl2, to ultraviolet light, and to x-rays.
In each case, the cells lost the power of reproduction (measured by the plate count) most rapidly. The loss of fermentation (measured by the CO2 pressure) was less rapid. Still slower was the change in staining reaction with methylene blue, and the loss of selective permeability of the plasma membrane (measured by the percentage of cells staining with Congo red). Slowest of all was the coagulation of protoplasm as observed in the dark-field.
In the case of death by heat or by HgCl2, the rate of loss of reproduction was about twice as rapid as that of the loss of fermentation, about three times that of the loss of semipermeability, and about forty times as large as the rate of coagulation. With ultraviolet light and with x-rays, these ratios were decidedly different.
The technique employed does not permit the conclusion that any one criterion of death is the prerequisite for other criteria. It does not appear probable that loss of reproduction is the prerequisite for loss of fermentation or of semipermeability because the ratios of the velocities of these processes are not the same with all causes of death.
There is no evidence that cells may show certain criteria of death immediately after exposure, and recover later.