bluuebunny/crossref_metadata_2025_split huggingface dataset:
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

The experiments indicate that the protoplasm of Nitella consists of an aqueous layer W with an outer non-aqueous surface layer X and an inner non-aqueous surface layer Y.
The potential at Y is measured by the magnitude of the action curve and the potential at X by the distance from the top of the action curve to the zero line. These potentials appear to be due chiefly to diffusion potentials caused by the activity gradients of KCl across the non-aqueous layers X and Y. The relative mobilities of K+ and Cl- in X and in Y can be computed and an estimate of the activity of KCl in W can be made. In the complete resting state the mobilities of K+ and Cl- in X are not very different from those in Y.
The action curve is due to changes in Y which suddenly becomes very permeable, allowing potassium to move from the sap across Y into W, and thus losing its potential. A gradual loss may be due to changes in ionic mobility in Y.
When recovery is incomplete and Y has not yet regained its normal potential a stimulus may cause a loss of the potential at Y giving an action curve of small magnitude. The magnitude may vary in successive action curves giving what is called a complex pattern in contrast to the simple pattern observed when recovery is complete and all the action curves are alike. Complex patterns occur chiefly in cells treated with reagents. Untreated cells usually give simple patterns.
A variety of complex action patterns is discussed. It is evident that the cells of Nitella show much more variation than such highly specialized cells as muscle and nerve which give stereotyped responses.
In some cases it may be doubtful whether the all-or-none law holds.
MOLECULAR ASSOCIATION OF HEMOCYANIN PRODUCED BY X-RAYS AS OBSERVED IN THE ULTRACENTRIFUGE
Authors: Pickels Edward G. , Anderson Rubert S. 
Published: May 2004

1. When normal, monodisperse hemocyanin (60.5S) from Limulus Rolyphemus was irradiated in neutral buffer with x-rays, several new, more rapidly sedimenting ultracentrifugal components (86S, 107S, 122S) were produced, with a corresponding loss in the amount of the unaffected protein. The amount of the effect was roughly proportional to the amount of irradiation.
2. The new resolvable components apparently represented an association of the primary particles into aggregates of 2, 3, and 4 primary particles respectively.
3. The proportional amount of hemocyanin affected decreased almost to the vanishing point as the concentration of the protein was raised to high levels.
4. The absolute effect, i.e. the total number of particles affected in a given volume, increased with the concentration of hemocyanin, at least for concentrations below 15 per cent.
5. The presence of 33 per cent horse serum during irradiation inhibited the effect on the hemocyanin almost completely, with hemocyanin concentrations of both 0.8 and 14 per cent.
6. The presence of 2.8 per cent egg albumin during irradiation lowered the effect by about 70 per cent in the case of dilute preparations (0.8 per cent hemocyanin), but by only about 25 per cent in the case of 14 per cent solutions.
7. A lowering of the solution's oxygen tension during irradiation enhanced the effect, almost doubling it in some cases.
8. The probable theoretical significance of these and other observations are discussed in the text.
THE PROLYTIC LOSS OF K FROM HUMAN RED CELLS
Authors: Ponder Eric 
Published: May 2004

The prolytic loss of K., i.e. the loss of K which takes place from red cells exposed to hypolytic concentrations of lysins, has been measured in systems containing distearyl lecithin, sodium taurocholate, sodium tetradecyl sulfate, saponin, and digitonin, by means of the flame photometer. The lysins are added in various concentrations to washed red cells from heparinized human blood, and the K in the supernatant fluids is determined after various intervals of time and at various temperatures. The prolytic loss Kp is compared in every experiment with the loss Ks into standard systems containing isotonic NaCl alone, with no lysin.
The losses Ks and Kp increase with time, so that new steady states are approached logarithmically. The values of Kp which correspond to the new steady states depend on the lysin used, being greatest with taurocholate and smallest with digitonin. The temperature coefficient of the loss is positive, and the extent and course of the losses have no apparent relation to the prolytic shape changes.
In systems in which the loss of K is appreciable, it can be inhibited by the addition of plasma or of either cholesterol or serum albumin. Of these two substances, even when used in quantities which have an approximately equal effect in inhibiting hemolysis, serum albumin is much the more effective.
Just as the prolytic loss of K occurs without the loss of any Hb, so in concentrations of lysin sufficient to produce hemolysis the loss of K, expressed as a percentage of the total red cell K, increases much more rapidly with lysin concentration than does the loss of Hb expressed as a percentage of the total Hb. The explanation of these relations depends on whether the loss of K is treated as being all-or-none in the case of the individual cell or as being the result of the loss of part of the K from all of the cells. This point has still to be decided.
CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR
Authors: Kunitz M. 
Published: May 2004

A study has been made of the general properties of crystalline soybean trypsin inhibitor. The soy inhibitor is a stable protein of the globulin type of a molecular weight of about 24,000. Its isoelectric point is at pH 4.5. It inhibits the proteolytic action approximately of an equal weight of crystalline trypsin by combining with trypsin to form a stable compound. Chymotrypsin is only slightly inhibited by soy inhibitor. The reaction between chymotrypsin and the soy inhibitor consists in the formation of a reversibly dissociable compound.
The inhibitor has no effect on pepsin.
The inhibiting action of the soybean inhibitor is associated with the native state of the protein molecule. Denaturation of the soy protein by heat or acid or alkali brings about a proportional decrease in its inhibiting action on trypsin. Reversal of denaturation results in a proportional gain in the inhibiting activity.
Crystalline soy protein when denatured is readily digestible by pepsin, and less readily by chymotrypsin and by trypsin.
Methods are given for measuring trypsin and inhibitor activity and also protein concentration with the aid of spectrophotometric density measurements at 280 mµ.
COMPARATIVE KINETICS OF HEMOLYSIS INDUCED BY BACTERIAL AND OTHER HEMOLYSINS
Authors: Bernheimer Alan W. 
Published: May 2004

A study has been made of the kinetics of lysis induced by various hemolytic agents. The course of bemolysis was followed by mixing lysin with washed human erythrocytes, removing samples from the mixture, and estimating colorimetrically the hemoglobin in the supernatant fluid of the centrifuged samples. Most of the curves (but not all of them, e.g. tyrocidine) obtained by plotting degree of hemolysis against time, were S-shaped. The initiation of lysis by streptolysin S' was delayed, and in this property, streptolysin S' was similar to Cl. septicum hemolysin. None of the other lysins studied exhibited a long latent period preceding lysis.
The maximum rate of hemoglobin liberation was found, in the range of lysin concentrations studied, to be a linear function of concentration when theta toxin of Cl. welchii, pneumolysin, tetanolysin, or streptolysin S' was the lytic agent. With comparable concentrations of saponin, sodium taurocholate, cetyl pyridinium chloride, tyrocidine, duponol C, lecithin-atrox venom mixture, or streptolysin O, the relation between rate and concentration was non-linear.
The critical thermal increment associated with hemolysis was determined for systems containing pneumolysin, theta toxin, streptolysin S', streptolysin O, tetanolysin, and saponin.
The findings concerning the effect of concentration and temperature on the rate of hemolysis provide a basis for classifying hemolytic agents (Tables I and II).
Hemolysis induced by Cl. septicum hemolysin was found to be preceded by two phases: a phase of alteration of the erythrocytes and a phase involving swelling. Antihemolytic serum inhibited the first but not the second phase while sucrose inhibited the second but not the first phase.
THE DARK ADAPTATION OF THE COLOR ANOMALOUS MEASURED WITH LIGHTS OF DIFFERENT HUES
Authors: Chapanis A. 
Published: May 2004

Determinations of minimum light thresholds as a function of time in the dark have been made for four color normal, three deuteranopic (or deuteranomalous), and four protanopic (or protanomalous) subjects. Measurements were made with red, reddish orange, yellow, green, violet, and white test lights.
Dark adaptation curves for the deuteranopes and deuteranomalous are essentially identical with those of the color normal for all colors.
The cone portions of the protanopic dark adaptation curves measured with the red, reddish orange, yellow, and white lights are higher than the corresponding data for the color normal, the discrepancy between the two sets of data decreasing from the long to short wave lengths. Dark adaptation curves for the protanopes and protanomalous measured with green and violet light are essentially normal in appearance.
A theoretical explanation is advanced to account for these findings in terms of the known sensitivity characteristics of the normal and color-anomalous eye.
THE RELATION OF ENZYMATIC ADAPTATION TO THE METABOLISM OF ENDOGENOUS AND EXOGENOUS SUBSTRATES
Authors: Spiegelman S. , Reiner John M. , Cohnberg Rosellen 
Published: May 2004

The source of energy for enzymatic adaptation has been investigated. Aerobically, it is found that the endogenous carbohydrate reserves may be used as such a source. In cells depleted of their reserves, the adaptive substrate itself can be oxidized even while it cannot be fermented, and so can serve as a source of energy for the adaptation to a fermentative mode of utilization.
Anaerobically, adaptation may occur at the expense of stored energy-rich compounds, while the reserves and the adaptive substrate are now useless as fuel. Such compounds appear to be more plentiful in young than in old cells. The addition of any fermentable substrate, such as glucose, leads to rapid anaerobic adaptation. Experiments in which maltose-adapted cells are adapted anaerobically to galactose with the aid of a little added maltose, and conversely, show that fermentability is the criterion of usefulness for an exogenous substrate in aiding the adaptive process.
None of the endogenous and exogenous energy sources which have been investigated will facilitate adaptation unless the adaptive substrate is present while they are being consumed.
The significance of these findings and the adequacy of "activation" hypotheses to explain enzymatic adaptation has been discussed.
STUDIES ON THE HEMOPHILUS GROUP OF ORGANISMS
Authors: Gilder H. , Granick S. 
Published: May 2004

The porphin requirements of the Hemophilus organisms have been studied. Organisms of the parainfluenzae group show quantitative differences in their ability to synthesize heme. The ability of the parainfluenzae organisms to grow appears to depend on the rate with which they synthesize heme and in part at least on the properties of the medium to protect the heme from peroxidative breakdown.
Quantitative studies of the growth of H. influenzae Turner on various iron porphins have been made. Iron protoporphin gives greatest growth when supplied in excess, although iron mesoporphin appears more efficient at lower concentrations. Iron deutero- and iron hematoporphin are much less effective. This suggests that although the vinyl groups are not essential for growth of the Turner organism they may be required for some particular enzymes which aid in attaining maximum growth.
A number of substances potentiate the growth-promoting properties of iron porphins. These substances include reducing agents and agents which destroy H2O2.
E. influenzae Turner appears to require heme for anaerobic as well as aerobic growth. The possibility of an essential heme enzyme functioning under anaerobic conditions must therefore be considered.
BACTERIOPHAGE FORMATION WITHOUT BACTERIAL GROWTH
Authors: Price Winston H. 
Published: May 2004

1. The addition of penicillin greatly increases the production of phage in bacterial suspensions containing 2.5 to 3.5 x 108 cells in 0.4 ml. broth plus 6.6 ml. Locke's solution.
2. Addition of niacin also greatly increases the formation of phage in the above system without the addition of penicillin.
3. The results indicate that niacin is necessary for phage production and that bacteria cannot utilize niacin in the presence of penicillin.
4. Staphylococcus muscae will grow in the synthetic medium of Fildes but do not form phage unless broth or yeast extract is added.
5. Phage formation requires the presence of one or more factors, besides niacin, present in broth and yeast extract which are not essential for bacterial growth. Penicillin does not prevent the utilization of the unknown substance or substances by the bacteria.
6. A solution containing biotin, guanine, adenine, ß-alanine, riboflavin, uracil, pyridoxamine, guanylic acid, adenylic acid, yeast nucleic acid, choline, p-aminobenzoic acid, a flavin component from liver, ribose, thymine, xanthine, folic acid, inositol, p-aminophenyl alanine, pantothentic acid and a strepogenin concentrate cannot replace broth or yeast extraction in increasing phage formation in the synthetic medium of Fildes.
7. The results indicate there is a continual competition between the bacteria and phage for certain essential building elements.
8. The results are discussed in relation to possible methods of control of virus diseases.
SOME CORRELATIONS BETWEEN DEVELOPMENT AND RESPIRATION IN THE SAND DOLLAR EGG, AS SHOWN BY CYANIDE INHIBITION STUDIES
Authors: Robbie W. A. 
Published: May 2004

Cyanide is a valuable tool for studying respiratory mechanisms and their rôle in embryonic development: it is relatively specific in its action, penetrates cell membranes readily, is active in low concentration, and may be controlled quantitatively (page 217).
Echinarachnius is extremely sensitive to cyanide and the oxygen consumption of both eggs and of sperm is almost completely inhibited by 10–5 M HCN (pages 219 and 221). Cell division is likewise arrested by the same concentration (page 223).
One of the pronounced effects of an irreversible dosage of cyanide is the marked cytolysis or breakdown of the egg, both internally and at the cell membrane. This cytolysis appears to be related to the state of metabolism, and its occurrence varies with both the respiratory and developmental activity of the cell (page 224).
The lethal dosage of cyanide varies with the state of development of the egg: the unfertilized egg is less susceptible than the fertilized one, and the susceptibility increases as the development of the fertilized egg proceeds (page 228).
The Echinarachnius egg differs from that of Arbacia in respiratory behavior chiefly in its inability to survive prolonged anoxia: the sea urchin egg will tolerate for 24 hours a concentration of cyanide that kills the sand dollar eggs in 30 minutes (page 229).
The Echinarachnius egg is apparently completely dependent upon cyanide-sensitive catalytic systems for its normal functioning and maintenance. Interference with this aerobic energy release mechanism results in irreversible damage to the egg (page 231).
PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES
Authors: Price Winston H. 
Published: May 2004

1. A factor necessary for the formation, of Staphylococcus muscae phage was found in acid digests of many highly purified proteins.
2. The factor is released from egg albumen and pepsin by peptic digestion.
3. No amino acids tried could replace the acid digests of proteins as a source of the factor.
4. The factor, when added to a multiplying bacteria-phage system, cannot be found in purified phage or in the lysate after complete lysis of the system has taken place.
SENSITIZATION TO HEAT BY X-RAYS
Authors: Giese Arthur C. , Heath H. Duane 
Published: May 2004

1. Paramecium caudatum is sensitized to heat by sublethal dosages of x-rays. Thus if paramecia are irradiated, then exposed to a sublethal dosage of heat they are killed, but if the same heat exposure precedes the same dosage of radiations, they are not.
2. Sensitivity to both heat and x-rays is much greater in paramecia from the log growth phase than in those from the stationary phase of a culture.
3. Recovery from heat sensitization in animals from the stationary phase of a culture is slow, requiring several days.
4. Division is readily retarded and even temporarily inhibited by sublethal dosage of x-rays. Recovery of the division rate is fairly slow requiring several days.
5. Paramecia can be killed by a dosage of 1,200,000 r (of which about one-half reach the animal) units of x-radiation alone. Smaller dosages are not lethal if the paramecia are transferred to fresh medium immediately upon completion of irradiation.
6. The possibility of utilization of heat sensitization in treatment of malignant growths is discussed.
EVIDENCE OF ACTIVE TRANSFER OF CERTAIN NON-ELECTROLYTES ACROSS THE HUMAN RED CELL MEMBRANE
Authors: LeFevre Paul G. 
Published: May 2004

1. Permeability of the human erythrocyte to glycerol, as indicated by the course of hemolysis and volume changes, is depressed by Cu++, Hg++, I2, p-chloromercuribenzoate, and phlorhizin, without effecting general permeability changes. In so far as tested (Cu++, p-ClHgB), these inhibitors delay exit of glycerol from the cell as well as its entry.
2. Permeability to glucose is similarly depressed by I2 and phlorhizin, and is extremely sensitive to Hg++ and p-chloromercuribenzoate, but is not affected by Cu++. An extensive series of other enzyme poisons is without effect in either system.
3. The effects of the sulfhydryl inhibitors are prevented or reversed in the presence of glutathione, cysteine, etc.
4. The kinetics of the volume changes in glucose-saline solutions indicates a mechanism for transport of glucose into the cell, regulated by the existing intracellular concentration, rather than by simple diffusion gradients.
5. The intermediation of a sulfhydryl group at the cell surface, probably an enzymatic phosphorylation, is suggested as an essential step in the passage of glycerol, glucose, and other like substances, across the human red cell membrane.
INTRACELLULAR GROWTH OF BACTERIOPHAGE STUDIED BY ROENTGEN IRRADIATION
Authors: Latarjet Raymond 
Published: May 2004

Growing Escherichia coli infected with bacteriophage T2 was x-rayed during the 21 minute latent period which elapses between infection and lysis of the cells. Survival curves of the infected bacteria were determined almost from minute to minute; they disclosed the following facts which are related to the process of phage growth:
During the first 7 minutes, the infective virus particle remains in the cell unique and genetically intact. The host cell synthesizes some ultraviolet-absorbing material probably devoted to building future particles. From the 7th to 9th minute the x-ray resistance of the virus particle increases, probably because of some internal change. Then, multiplication starts and is completed at about the 13th minute, when an average of 130 virulent units is present per cell, displaying an x-ray resistance twice as high as that of the extracellular virus particle. From 13 minutes to the end, the new units progressively recover the x-ray sensitivity of the extracellular virus.
Nothing can be said about either the rate of multiplication between 9 and 13 minutes, or the nature of the multiplying units, except that they are more radiation-resistant (probably smaller) than the extracellular virus.
The first steps of the growth process are favored by an unknown component of the lysate, different from the active particles. Several particles can grow in the same host cell.
METABOLIC CONDITIONS IN CHLORELLA
Authors: Myers Jack , Cramer Marian 
Published: May 2004

1. The effect of nitrate reduction and assimilation on the CO2/O2 quotient of gas exchange has been used as an index of the relative rates of carbon and nitrogen assimilation in Chlorella pyrenoidosa. Changes in over-all metabolism induced by starvation, high light intensity, and nitrogen deficiency have been studied in comparison with the metabolism of cells growing at light-limiting intensities.
2. Starvation, which results in depletion of carbohydrate reserves, gives rise to a high CO2/O2 quotient (∼0.9) during photosynthesis and, therefore, a high C/N assimilation ratio. Starved cells apparently restore their normal C/N ratio before becoming growing cells.
3. Under photosynthesis-saturating light intensities cells show the high CO2/O2 quotient (0.9) indicative of a high C/N assimilation ratio. Return to low light intensities is followed by the abnormally low CO2/O2 quotient (∼0.4) of a low C/N assimilation ratio. High light intensity apparently gives rise to a condition of a limiting rate of nitrogen assimilation and to an overflow metabolism analogous to that found in other microorganisms.
4. Nitrogen deficiency leads to a completely carbohydrate metabolism in short time experiments and makes still more pronounced the effects characteristic of high light intensity alone.
5. Considerations of nutritional economy sustain the experimental evidence in establishing the metabolism of cells growing under light-limiting intensities as the normal or reference metabolic condition in Chlorella.
OBSERVATIONS ON THE MOTILITY OF RABBIT SPERMATOZOA IN DILUTE SUSPENSION
Authors: Emmens C. W. , Swyer G. I. M. 
Published: May 2004

1. Rabbit spermatozoa suspended in Baker's solution rapidly lose motility at relatively high dilutions. At a concentration of 0.4 million per ml., the spermatozoa from most ejaculates are completely immotile within 2 or 3 hours. The same phenomenon occurs with chloride-free diluents and is therefore not due to the toxic action of chlorides.
2. This rapid immobilisation may be prevented by suspension in cell-free supernatants from other more concentrated suspensions of rabbit semen and by the accessory secretions from a vasectomised buck. The most effective supernatants are those prepared from suspensions of spermatozoa which have been left overnight before centrifuging. Immobilisation may also be prevented by many other agents, the most effective of which are gum arabic, starch, glycogen, and serum proteins (carbohydrate-containing or carbohydrate-free). Yet, in no case is the action of these substances as effective as more concentrated suspension in Baker's solution.
3. The immobilisation is not prevented by catalase, gelatin, agar, or sodium silicate. It is almost certainly not due to the toxic action of traces of heavy metals and is not affected by the use of water doubly distilled over glass in the preparation of the diluent, or by treating the diluent with activated charcoal.
4. Washing with Baker's solution does not cause immobilisation of spermatozoa suspended at 20 million per ml. at a stage at which the concentration of seminal plasma has been reduced to that equivalent to dilution to 0.4 million per ml. Further washing (six repeated centrifugings of 0.2 ml. semen in 4 ml. of Baker's solution) immobilises them. This confirms the opinion that loss of intracellular, or perhaps rather paracellular, material is a responsible agent in the dilution phenomenon.