bluuebunny/crossref_metadata_2025 huggingface dataset:
TISSUE CULTURE STUDIES
Authors: Hull Wayne , Kirk Paul L.
Published: May 2004

An improved procedure for measuring the uptake of tracer P32 by tissues in culture is described. It consisted of counting the ß-emissions through a specially designed roller tube in which the culture medium could be effectively removed from the system without opening or damaging the cultures.

In standard growth-promoting medium, the uptake was shown to be markedly greater than in Tyrode's solution. The uptake curve was found to be essentially parallel with the uptake of P32 in desoxyribo- and ribonucleic acids when standard medium was used, and in desoxyrihonucleic acid when Tyrode's solution was used. This is interpreted to signify that the total uptake of tracer phosphorus approximates the growth in the culture.

The value of uptake measurements as a frame of reference for comparison of various types of media and of metabolic studies is indicated.
EFFECTS OF ELECTRICAL CURRENTS ON THE ABSORPTION OF WATER BY EGGS OF NEREIS LIMBATA
Authors: Osterhout W. J. V.
Published: May 2004

Unfertilized eggs of the marine worm Nereis limbata subjected to electrical currents (direct or alternating) undergo remarkable changes. Certain minute granules just inside the surface of the egg absorb water and swell to more than 300 times their original size and thereby produce a mass of jelly which surrounds the egg with a zone about as wide as the original diameter of the egg. The amount of direct current is too small to produce any change of color in eggs stained with neutral red.

In direct current the jelly appears first on the side toward the anode and moves toward the anode. In alternating current it appears on opposite sides facing the electrodes.

It might be thought that the current changes the chemical character of the granules so that they are able to absorb very large quantities of water but this seems unlikely.

If the current is shut off after 1 minute the swelling continues. This might be explained on the ground that each jelly precursor granule is covered with a waterproof film which is removed by the current.

It does not seem probable that the effect is due to heat produced by the current since the exposure is so short. It seems possible that the current may strip off micelles from the waterproof covering of the granules and allow water to penetrate.

The fact that alternating current is more effective than direct current might be explained on the ground that the egg may be represented as a capacity in parallel with a resistance so constituted that relatively little direct current can enter.

The non-aqueous film which covers the surface of the protoplasm appears to be liquid rather than solid.
PURINE AND PYRIMIDINE CONTENTS OF SOME DESOXYPENTOSE NUCLEIC ACIDS
Authors: Daly M. M. , Allfrey V. G. , Mirsky A. E.
Published: May 2004

The distribution of purines and pyrimidines in desoxypentose nucleic acids prepared from a variety of animal and plant sources has been studied.

1. The nucleic acids were prepared from calf thymus, calf kidney, sheep spleen, horse spleen, chicken erythrocyte, turtle erythrocyte, trout sperm, shad testes, sea urchin sperm, wheat germ, and Pneumococcus Type III.

2. Separate hydrolyses were carried out for the determination of purines and pyrimidines. These procedures permitted nearly quantitative recovery of nucleic acid phosphorus in many of the preparations examined.

3. In the case of those preparations where a quantitative recovery was obtained it can be concluded that no bases other than adenine, guanine, thymine, and cytosine were present in appreciable amounts.

4. The distribution of purines and pyrimidines in all the nucleic acids studied renders the tetranucleotide hypothesis untenable.

5. The results of the analyses have indicated no great differences in the composition of these nucleic acids with respect to purines and pyrimidines.
THE INTRINSIC VISCOSITY OF MIXED PROTEIN SYSTEMS, INCLUDING STUDIES OF PLASMA AND SERUM
Authors: Hess Eugene L. , Cobure Aspascia
Published: May 2004

Experimental evidence is presented that the intrinsic viscosity of solutions of mixed proteins obeys the additive equation

See PDF for Equation.

The datum serves to characterize the system, and combined with other analytical techniques and fractionation procedures, enables one to analyze and characterize subfractions. The plasmas and sera of clinically "normal" individuals give intrinsic viscosity values agreeing with calculated values. The intrinsic viscosity values for pathological plasmas and sera in all cases are greater than normal and reflect the augmented levels of those proteins fibrinogen, α2-globulins, and γ-globulins occurring in the pathological state. The method is readily adaptable to routine clinical use and furnishes a measure of the departure from normal of protein levels in serum and plasma.
OXIDATIVE PHOSPHORYLATION BY A CELL-FREE PARTICULATE SYSTEM FROM UNFERTILIZED ARBACIA EGGS
Authors: Keltch A. K. , Strittmatter C. F. , Walters C. P. , Clowes G. H. A.
Published: May 2004

1. A cell-free particulate system capable of effecting oxidative phosphorylation has been prepared from unfertilized eggs of Arbacia punctulata.

A substantial increase in phosphorylation can be produced by addition of α-ketoglutarate, oxalacetate, or succinate, the magnitude of the increase being greatest with α-ketoglutarate.

The activity of the phosphorylating system is sharply dependent on maintenance of a comparatively narrow pH range during both the preparation of the particulate system and its subsequent incubation with oxidizable substrate.

2. The maximum oxygen consumption of the cell-free particulate system derived from a given weight of unfertilized eggs is about three times that of the same weight of intact unfertilized eggs and approximately the same as that of an equal weight of fertilized eggs.

3. The data indicate that generation of high-energy phosphate bonds in the Arbacia egg is coupled, as it is in mammalian liver or kidney, with the functioning of the tricarboxylic acid cycle.
AN ANALYSIS OF THE RELATIONSHIP BETWEEN SOLUBILITY AND STIMULATING EFFECT IN TARSAL CHEMORECEPTION
Authors: Dethier V. G. , Chadwick L. E.
Published: May 2004

The rejection thresholds of the blowfly Phormia regina Meigen for a selected series of substituted aliphatic hydrocarbons have been determined and an analysis made of the effect on stimulation of increasing the number of like substitutions from one to two, of the interaction of different types of substituent, and of the position of the substituent in the molecule.

The order of stimulating efficiency (reciprocal of rejection threshold) of the functional groups which have been studied is: Br > Cl ? CH3 ? CHO > C=O > OH. There is a consistent decrease in stimulating effect following the introduction of a second hydroxyl group. The introduction of a second C=O has little effect. Introduction of a second halogen is generally followed by a decrease in threshold. Two different species of functional group, one of which tends to increase water solubility and the other to decrease it, tend to counter-balance each other.

A single oxygen-containing functional group on the end of the molecule or two of these groups which are terminal reduce the stimulating effect less than when one or more of such groups are subterminal or located elsewhere within the molecule. Branching of the carbon chain decreases effectiveness. Sulfur and oxygen linkages also decrease effectiveness. In general, the length of the free alkyl group largely determines the stimulating effectiveness. Its power is modified to varying degrees by the nature of the attached polar groups.

Of all chemical properties examined, solubility alone agrees consistently with the foregoing data. Threshold varies directly with the molar solubility of the compounds in water. The fact that the threshold values for individual compounds are frequently different from those which would be expected solely on the basis of the correlation between threshold and solubility in water suggests that other factors are also concerned in stimulation. These have not yet been identified.
FREE AMINO ACIDS AND NUCLEIC ACID CONTENT OF CELL NUCLEI ISOLATED BY A MODIFICATION OF BEHRENS' TECHNIQUE
Authors: Dounce Alexander L. , Tishkoff Garson H. , Barnett Shirley R. , Freer Richard M.
Published: May 2004

1. Nuclei were prepared from frozen rat liver by a modification of the technique of Behrens, and were studied with regard to the content of free amino acids and nucleic acid.

2. Under rigorously controlled conditions, preparations of nuclei are obtained by the Behrens' method which form a gel in the presence of 5 or 10 per cent NaCl or of water plus a small amount of dilute alkali; whereas when conditions are less rigorously controlled, nuclei are obtained which form no such gel. The property of forming gels with alkali is probably characteristic of all cell nuclei which have not undergone autolysis.

3. Nuclei prepared by the Behrens' technique contain the enzymes arginase, catalase, and esterase in very appreciable concentrations.

4. The free amino acids of the isolated cell nuclei, as well as of other liver cell fractions, have been investigated using the technique of paper chromatography.

5. The chromatographic patterns of the free amino acids of whole cells, ground cytoplasm, and isolated cell nuclei were very similar or identical. A feature of interest in these chromatograms was the faintness or absence of the spots due to a number of the essential amino acids, as compared to the intensities of the spots due to glycine, alanine, and glutamic acid. Glutathione was present in the isolated nuclei as well as in the whole cells.

6. Chromatograms made from hydrolysates of nuclei showed high concentrations of the essential amino acids and were similar to chromatograms of hydrolysates of typical proteins.
RATE OF POTASSIUM EXCHANGE OF THE HUMAN ERYTHROCYTE
Authors: Raker John W. , Taylor Isaac M. , Weller John M. , Hastings A. Baird
Published: May 2004

1. The exchange of potassium by the human erythrocyte has been studied in vitro using radioactive potassium.

2. An incubation technique which maintains erythrocytes in an essentially normal state for over 48 hours was employed.

3. Exchange of radioactive potassium between the red cells and the extracellular fluid was regular and progressive, the specific activities of the intra- and extracellular fluids reaching equal values. This indicates that all the erythrocyte potassium is exchangeable and is exchanging at the same rate.

4. From these data, it was calculated that at 37°C., 1.6 per cent of the erythrocyte potassium exchanges per hour, corresponding to an exchange of 1.5 mM of potassium per liter of red cells per hour. The time required for the exchange of 50 per cent of the red cell potassium is calculated to be 43 hours.

5. The temperature coefficient (Q10) of the potassium exchange rate is 2.2. This is the same as the temperature coefficient of the rate of utilization of glucose by the human erythrocyte.

6. Varying the percentage of red cells, plasma potassium concentration, initial glucose level, and pH between 7.0 and 7.7 had no effect on the potassium exchange rate.
CATION EXCHANGE BETWEEN CELLS AND PLASMA OF MAMMALIAN BLOOD
Authors: Sheppard C. W. , Martin W. R.
Published: May 2004

The exchange of potassium between cells and plasma of heparinized human blood has been studied in vitro using the radioactive isotope K42. The changes in cell and plasma specific activity are characteristic of a simple two-compartment system. The mean of seven determinations of the exchange rate at 38°C. is 1.8 per cent of the cellular potassium per hour. The results indicate that at 38°C. the rate is relatively insensitive to oxygenation or reduction of the hemoglobin, and to 1200 r of gamma radiation. With varying temperature the rate follows pseudo first order kinetics with a Q10 of 2.35. Below 15°C. the rate of loss of potassium exceeds the rate of uptake.
ON THE VISIBILITY OF RADIATION AT THE HUMAN FOVEA
Authors: Crozier W. J.
Published: May 2004

1. Seeing-frequency functions (ψ[S]) determined uniocularly for small (1.6'), brief images at the thoroughly dark-adapted human central fovea take the form of log-Gaussian integrals, for intensity or for exposure-time as the independent variable. They cannot be of Poisson type, since mean (τ') and standard deviation (σ) are quite independently modifiable.

2. The properties of τ', the abscissa of inflection in the log-Gaussian integrals, and of σ, are discussed in relation to customary determinations of spectral visibilities; agreements and certain necessary divergences are considered.

3. The values of σlogΔIlogΔI0, are distributed periodically, with 5 maxima in the range λ383 to λ712. Outside the fovea this is not the case. These maxima, and the intervening minima, are definitely correlated with "irregularities" in the values of τ' as function of λ, with data on color threshold intensities, with data on "saturation," and quite specifically with minima and maxima in the data of λ discrimination. They are unmistakably of analytical significance.

4. The interpretation of these properties is taken to require (consistent with the indications of other evidence) that under specified conditions the magnitude of σ is a measure of the "size" of the population of excitable elements of neural effect, in the range of 0 to 100 per cent response-frequency as a function of wave number. This means that under the procedure used there is detectable the spectral distribution of local, specific, photosensitization. The σ's refer to a property of the excitation process which is not affected by the action of irrelevant absorbers.

5. A preliminary test of this has been made by the use of mixed "monochromatic" lights. The total energy is empirically the significant quantity, although the separate effects of λ's are sharply exhibited.

6. The λ distribution of photosensitization indices, σlogΔIlogΔI0, is necessarily taken to have the nature of "action spectra." Careful search discloses, surprisingly enough, precise and apparently unique correspondence with the maxima and minima (and details of shape) required for the participation of: cytochrome-c reductase; the reduced forms of cytochromes-a and -c; and the often overlooked ferric-prophyrin bands of oxidized cytochrome-c.

7. For the central fovea, in which blood vessels are absent, and in which resistance to anoxia is at a maximum, the presence of an enzyme system of the sort here indicated is entirely reasonable. It is pointed out that a number of specific experiments can be based upon the general finding, whatever the causal mechanism for the sensitized λ regions may in the end prove to be. The data cannot be reconciled to the demands of existing color primary theories, although apparently quite accurately consistent with varied observational data.
THE INTERACTION BETWEEN THE SYNAPSES OF A SINGLE MOTOR FIBER
Authors: Wiersma C. A. G. , Turner R. S.
Published: May 2004

It has been shown that stimulation of synapses of the giant motor fibers of the third roots of Cambarus clarkii can block transmission at other synapses located on the same fiber. Peripherally located synapses block most synapses which are more centrally located. The reverse is true in a small number of cases. Possible reasons for this difference are discussed.

It was further found that the two medial giant fibers in fresh, carefully dissected, preparations show a functional connection in the brain. It is probable that, under natural conditions, both medial giant fibers are always active at the same time.
METHYL GREEN
Authors: Kurnick N. B. , Foster Marilee
Published: May 2004

1. Methyl green ("ethyl green") C. I. Number 685 was examined and found to behave identically with methyl green C. I. Number 684 (no longer available) in respect to molar extinction coefficient, effect of combination with polymerized DNA, failure to react with depolymerized DNA, and effect of pH.

2. The mass law permits the calculation of P/dye. This is found to be 13 P/dye. The same value is obtained when an excess of methyl green is caused to fade by adjusting the pH to 7.5.

3. The compound formed by methyl green with DNA has the same maximum absorption at 642.5 to 645 mµ in the pH range 3.5–7.8, whereas the free dye fades markedly above pH 5.0.
THE ACCELERATING ACTION OF ILLUMINATION IN RECOVERY OF ARBACIA EGGS FROM EXPOSURE TO ULTRAVIOLET RADIATION
Authors: Blum Harold F. , Loos Gordon M. , Robinson J. Courtland
Published: May 2004

Light of wave lengths 0.30µ to 0.50µ, accelerates return of the cleavage rate of Arbacia eggs to normal, after delay by exposure to ultraviolet radiation (wave lengths 0.238µ to 0.31µ). Recovery is apparently complete. Wave lengths 0.30µ to 0.50µ have no effect on the cleavage rate of normal eggs, nor does such illumination previous to dosage with ultraviolet radiation influence subsequent recovery. Acceleration of recovery of the egg occurs before fertilization as well as after.

The effects of ultraviolet radiation and recovery therefrom are essentially the same in nucleated "white halves" as in the intact eggs.

This phenomenon in the Arbacia egg seems basically comparable to photoreactivation of bacteria and fungi.
CHANGES IN THE POTASSIUM CONTENT OF SEA URCHIN EGGS ON FERTILIZATION
Authors: Oddo Anna Monroy , Esposito Maria
Published: May 2004

In the eggs of Arbacia lixula and Paracentrotus lividus an uptake of K occurs during the first 10 minutes following fertilization. Between 10 and 40 minutes K is then released. Both in Arbacia and in Paracentrotus the minimum point of the curve coincides with the nuclear streak stage. A maximum loss of 25 per cent in Arbacia and 20 per cent in Paracentrotus with respect to the amount present in the unfertilized eggs has been found. From 40 minutes up to 1 hour K undergoes a further increase and when the first cleavage sets in the same amount of K is present as in the unfertilized eggs.

By treating the eggs with K-free artificial sea water it has been established that about 60 per cent of the K content of the eggs is in a non-diffusible condition. Also under such conditions the eggs when fertilized are able to take up even the very small amount of K present in the medium that was released by them prior to fertilization.
THE CHEMICAL COMPOSITION AND THE OSMOTIC PRESSURE OF THE AQUEOUS HUMOR AND PLASMA OF THE RABBIT
Authors: Kinsey V. Everett
Published: May 2004

Measurements were made of the osmotic pressure of plasma, and of aqueous humor taken from the anterior chamber of the right and left eyes and from the posterior chamber of unanesthetized rabbits. Aqueous humor from the anterior chamber was found to be hypertonic to the plasma by approximately 3 mM/liter equivalent of sodium chloride. The aqueous humor from the anterior and posterior chambers of the right and left eyes was isotonic. The concentration of chloride in the anterior and posterior chambers was the same.

The concentration of all the major components of the aqueous humor and plasma has been determined by chemical analysis on fluid samples obtained from unanesthetized rabbits at approximately the same time. The calculated osmotic pressure of the total of these substances in terms of sodium chloride equivalent agrees to within better than 1 per cent of the total osmotic pressure as measured experimentally.

The distribution of some individual anions and cations of the aqueous humor and plasma was determined. This distribution is widely different from that which would obtain at a state of equilibrium. The positive and negative charges carried by the ions in the aqueous humor were approximately equal. Sources of error in the experiments are discussed.
RELATIVE CONCENTRATIONS OF N15 IN URINARY AMMONIA N AND UREA N AFTER FEEDING N15-LABELED COMPOUNDS
Authors: Wu Hsien
Published: May 2004

Available data on the isotopic ratio

See PDF for Equation

of ammonia (ra)

and that of urea (ru) after a single feeding of glycine, aspartic acid, and ammonium citrate are analyzed. From this analysis the following conclusions are drawn.

1. The isotopic ratio

See PDF for Equation

of ammonia (ra) is always higher than that of urea (ru) in the initial period after a single feeding of isotopic glycine or aspartic acid, but the relation is reversed later. A similar relation probably holds after feeding isotopic ammonia.

2. It is pointed out that the ratio of average ra to average ru depends on the time interval for which urine is collected, on the schedule of feeding, and probably also on the amount taken at each feeding. When the amount fed and the feeding schedule are unknown, theoretical interpretation of the ratio of average ru to average ru is impossible.

3. At the point of maximum isotopic ratio of urea, it is very probably equal to the isotopic ratio of ammonia. A possible explanation is suggested.
CATION EXCHANGE BETWEEN CELLS AND PLASMA OF MAMMALIAN BLOOD
Authors: Sheppard C. W. , Martin W. R. , Beyl Gertrude
Published: May 2004

Sodium and potassium exchange has been studied in the blood of the sheep, dog, cow, and man. The potassium exchange rate in human cells is practically unaltered by increasing the plasma potassium concentration approximately threefold. Comparing the results in different species the exchange rate for potassium shows a rough correlation with the intracellular amount of the element. Expressed in per cent of the cellular content sodium tends to exchange more rapidly than potassium. In three instances the specific activity curves deviate from the simple exponential behavior of a two compartment system. In the exchange of potassium in canine blood the deviation is caused by the presence of a rapidly exchanging fraction in the buffy coat cells. Such an effect does not account for the inhomogeneity of sodium exchange in human blood.
THE COMPOSITION AND STRUCTURE OF ISOLATED CHROMOSOMES
Authors: Mirsky A. E. , Ris H.
Published: May 2004

1. The preparation of isolated chromosomes from liver, kidney, and pancreas has been described.

2. It has been shown that there is no gross cytoplasmic contamination in these preparations.

3. In a microscopic study of isolated chromosomes the same chromosomes have been found in different tissues of the same organism. Since individuality is one of the main characteristics of chromosomes, there can be little doubt that the preparations do, in fact, contain isolated chromosomes.

4. A quantitative study of staining with crystal violet shows that this basic dye competes with histone for the phosphoric acid groups of the DNA in chromosomes. The displacement of histone by protamine has been demonstrated.

5. Preparation of histone-free chromosomes has been described. Removal of histone does not affect the microscopic appearance of chromosomes.

6. The non-histone or residual protein has been prepared from histone-free chromosomes. The quantity of residual protein in a preparation of chromosomes is correlated with the amount of cytoplasm in the cells from which the chromosomes were prepared.

7. The microscopic appearance of chromosomes depends upon the association of DNA with residual protein.

8. Evidence has been given that in a chromosome there are two DNA-containing nucleoproteins; in one DNA is combined with histone, and in the other it is combined with residual protein.
MECHANISMS INVOLVED IN FIBRIN FORMATION
Authors: Boyles Paul W. , Ferguson John H. , Muehlke Paul H.
Published: May 2004

That the role of thrombin in the conversion of fibrinogen to fibrin is essentially enzymatic, is established not only by the minute amounts of thrombin which are effective but also by the complete independence of fibrin yields and thrombin concentrations over a very wide range of thrombin dilutions and clotting times. The thrombin-fibrinogen reaction, in the phase beyond the "latent period" at least, seems fundamentally "first order." Technical requirements of the experiments leading to these conclusions include: (1) a highly purified (e.g. 97 per cent "clottable") fibrinogen, (2) absence of traces of thrombic impurities in the fibrinogen, (3) absence of fibrinolytic protease contaminant of the thrombin and the fibrinogen, and (4) sufficient stability of the thrombin even at very high dilutions. Four conditions affecting thrombin stability have been investigated.

Fibrin yields are not significantly modified by numerous experimental circumstances that influence the clotting time, such as (1) temperature, (2) pH, (3) non-specific salt action due to electrical (ionic) charges, which alter the Coulomb forces involved in the fibrillar aggregation, (4) specific ion effects, whether clot-accelerating (e.g. Ca++) or clot-inhibitory (e.g. Fe(CN)6''''), (5) occluding (adsorptive) colloids, which have a "fibrinoplastic" action, e.g. (a) acacia and probably (b) fibrinogen which has been mildly "denatured" by salt-heating, acidification, etc.

The data with which several European workers have attempted to substantiate the idea of a two-stage thrombin-fibrinogen reaction with an intermediary "profibrin" (allegedly partly "denatured") have been reanalyzed with controls which lead us to very different conclusions, viz. (1) denaturation and fibrin formation are independent; (2) partial denaturation is "fibrinoplastic" (see above); and (3) conditions of strong salinity and acid pH (5.1) usually do not completely prevent the thrombin-fibrinogen reaction but merely prolong the "latent" phase and lessen the time required for completion of essentially the same reaction (fibrin polymerization) when more favorable clotting conditions are restored.

Thus, our experiments advance the modern concepts concerning the coagulation mechanisms along lines that, for the most part, agree with those of the Harvard physical chemists, and we oppose the European views concerning a two-stage reaction, "profibrin," and "the denaturase theory" of clotting.
THE REVERSIBLE HEAT DENATURATION OF CHYMOTRYPSINOGEN
Authors: Eisenberg Max A. , Schwert George W.
Published: May 2004

Within a restricted range of pH and protein concentration crystalline chymotrypsinogen undergoes thermal denaturation which is wholly reversed upon cooling. At a given temperature an equilibrium exists between native and reversibly denatured protein. Within the pH range 2 to 3 the amount of denatured protein is a function of the third power of the hydrogen ion activity. The presence of small amounts of electrolyte causes aggregation of the reversibly denatured protein. A specific anion effect has been observed at pH 2 but not at pH 3. Both the reversible denaturation reaction and the reversal reaction have been found to be first order reactions with respect to protein and the kinetic and thermodynamic constants for both reactions have been approximated at pH 2 and at pH 3. Renatured chymotrypsinogen has been found to be identical with native chymotrypsinogen with respect to crystallizability, solubility, activation to δ-chymotrypsin, sedimentation rate, and behavior upon being heated.

Irreversible denaturation of chymotrypsinogen has been found to depend on pH, temperature, protein concentration, and time of heating. Irreversible denaturation results in an aggregation of the denatured protein.
EXPERIMENTS ON THE ROLE OF POTASSIUM IN THE BLOCKING OF NEUROMUSCULAR TRANSMISSION BY CURARE AND OTHER DRUGS
Authors: Fenn Wallace O. , Gerschman Rebeca , Fischer George , Lacy Jane , Bailly Margaret D. , Wright Joan L.
Published: May 2004

1. Experiments with perfused frog muscles and with isolated frog muscles immersed in Ringer's solution have failed to show any effect of curare in liberating potassium from muscle tissue. This makes it difficult to suppose that the paralytic effect of curare can be attributed to cation exchange between curare and K whereby a labile potassium compound needed for stimulation is removed from the neuromuscular junction.

2. Similar negative results were obtained with dihydro-ß-erythroidine and myanesin.

3. A small liberation of K from perfused muscle does result from treatment with acetylcholine. This is probably due to the contracture of the muscle since the effect is largely eliminated by previous treatment of the muscle with curare. The amount of potassium lost in this way from perfused muscles is too small to detect when muscles are analyzed after immersion in Ringer's solution with and without acetylcholine. It is concluded that there is no significant cation exchange between acetylcholine and K in muscle, but only a small loss of K due to the contracture produced by the acetylcholine.
THE EFFECT OF VARYING THE INTENSITY AND THE DURATION OF PREEXPOSURE UPON FOVEAL DARK ADAPTATION IN THE HUMAN EYE
Authors: Mote F. A. , Riopelle A. J.
Published: May 2004

The course of foveal dark adaptation was studied as a function of the intensity and duration of preexposure. Four intensities (11,300, 5,650, 1,130, and 565 mL.) and four durations (300, 150, 30, and 15 seconds) were used in all combinations of intensity and duration. The threshold-measuring instrument was a monocular Hecht-Shlaer adaptometer and the threshold measurements were recorded in log micromicrolamberts. There were two subjects and each went through the complete series of intensities and durations five times. The five logarithmic values obtained for each threshold were converted into a geometric mean and these means were the data used in the analysis of the results. The chief results were as follows:—

1. For each subject the final steady threshold value was in the region of 7.0 log µµL.

2. As the intensity, or duration, or both, were increased the initial foveal dark adaptation threshold rose, the slope of the curve decreased, and the time to reach a final steady threshold value increased.

3. For those values of preexposure intensity and time for which the product, I x t, is a constant it was found that for the two higher intensities and two longer durations and also for the two lower intensities and two shorter durations, the dark adaptation curves were the same. For other values of I x t = C the curves were generally not the same.
MITOCHONDRIA IN THE FLIGHT MUSCLES OF INSECTS
Authors: Watanabe Mary Ishimoto , Williams Carroll M.
Published: May 2004

1. The "indirect" thoracic muscles of adult dipterous and hymenopterous insects consist of a unique type of muscle characterized by the presence of numerous spherical, intracytoplasmic bodies termed "sarcosomes."

2. When the muscle is teased or ground, the sarcosomes are liberated as a turbid suspension of bodies ranging from 1 to 4 µ in diameter. A method is described for the isolation of sarcosomes by a simple differential centrifugation.

3. The cytochemical, chemical, and enzymatic properties of sarcosomes were examined for the purpose of appraising their relation to the cytoplasmic bodies of other tissues.

4. Fresh sarcosomes are slowly but selectively stained by the mitochondrial reagents, Janus green B and pinacyanol. Fixed sarcosomes give a positive reaction with Regaud's mitochondrial stain.

5. Chemical analyses show that approximately 29 per cent of the dry weight of sarcosomes consists of lipids and 60 per cent of protein. Microbiological assay indicates the presence of about 1 gamma of riboflavin per milligram of nitrogen. These values resemble those reported for isolated mitochondria of vertebrate liver and kidney.

6. When examined spectroscopically the sarcosomes, like the vertebrate mitochondria, show a high titer of cytochromes a, b, and c.

7. The titer of cytochrome oxidase varies systematically with the adult age of the insect. A similar relation is observed for the enzyme catalase.

8. Isolated sarcosomes show significant titers of succinoxidase, α-glycerophosphate dehydrogenase, malic dehydrogenase, and pyruvic dehydrogenase. The following dehydrogenases could not be demonstrated: xanthine, phenylalanine, glycine, lactic, choline, glutamic, and alcohol. These results are compared with those previously reported for vertebrate mitochondria.

9. In view of their manifold points of biochemical similarity, it is concluded that the sarcosomes are the mitochondria of this highly specialized muscular tissue.
CATION EXCHANGE IN MAMMALIAN ERYTHROCYTES
Authors: Sheppard C. W. , Beyl Gertrude E.
Published: May 2004

Freshly drawn heparinized human whole blood is exposed to x-rays in amounts up to 54,000 r in vitro and then equilibrated under a controlled atmosphere at 24 or 38°C. For as long as 26 hours following exposure, potassium is progressively lost from the cells and quantitatively replaced by sodium with little, if any, osmotic disturbance. The mean rate of loss at 20,000 r and 24°C. is about 0.4 per cent of the initial cell potassium per hour and approximately doubles for a 20,000 r increase. It is accentuated if blood is stored at low temperature (5°C.) following radiation exposure. Isotope experiments show that the rate of entrance of potassium into the cells is practically unaltered, the principal effect being an acceleration of the rate from cells to plasma. This suggests that radiation may have interfered with a mechanism of selective potassium accumulation based on preferential retention of the element. The sodium which enters the cells following irradiation contributes to the rapidly exchanging portion of the cellular sodium, suggesting that this fraction is ionic sodium.
GROWTH AND PHAGE PRODUCTION OF LYSOGENIC B. MEGATHERIUM
Authors: Northrop John H.
Published: May 2004

Cell multiplication and phage formation of lysogenic B. megatherium cultures have been determined under various conditions and in various culture media.

1. In general, the more rapid the growth of the culture, the more phage is produced. No conditions or culture media could be found which resulted in phage production without cell growth.

2. Cultures which produce phage grow normally, provided they are shaken. If they are allowed to stand, those which are producing phage undergo lysis. Less phage is produced by these cultures than by the ones which continue to grow.

3. Cells plated from such phage-producing cultures in liquid yeast extract medium grow normally on veal infusion broth agar or tryptose phosphate broth agar, which does not support phage formation, but will not grow on yeast extract agar.

4. Any amino acid except glycine, tyrosine, valine, leucine, and lysine can serve as a nitrogen source. Aspartic acid gives the most rapid cell growth.

5. The ribose nucleic acid content is higher in those cells which produce phage.

6. The organism requires higher concentrations of Mg, Ca, Sr, or Mn to produce phage than for growth.

7. The lysogenic culture can be grown indefinitely in media containing high phosphate concentrations. No phage is produced under these conditions, but the cells produce phage again in a short time after the addition of Mg. The potential ability to produce phage, therefore, is transmitted through cell division.

8. Colonies developed from spores which have been heated to 100°C. for 5 minutes produce phage and hence, infected cells must divide.

9. No phage can be detected after lysis of the cells by lysozyme.
LOSS AND RECOVERY OF EXCITABILITY BY NORMAL AND BY DEGENERATING NERVES DEPRIVED OF SODIUM
Authors: Gallego A.
Published: May 2004

A study has been made of the loss of excitability in a sodium-free medium and of the recovery of excitability in Ringer's solution by A fibers of normal frog nerves and of nerves in advanced stages of Wallerian degeneration.

With normal nerves that are being kept in a sodium-free medium the number of conducting fibers does not undergo a readily detectable decrease in less than 1 to 2 hours; inexcitability of all the A fibers does not develop in less than 7 to 8 hours. During the development of inexcitability the speed of conduction of the still conducting fibers undergoes a progressive decrease; in advanced stages the speed of conduction is not more than one-fifth of the normal speed. The nerve fibers lose the ability to conduct rhythmic trains of impulses earlier than the ability to conduct single impulses.

The recovery of excitability in Ringer's solution duplicates in a reverse order the sequence of changes that have been previously observed during the development of inexcitability. The rate of the recovery of excitability in Ringer's solution is higher than the rate of the loss of excitability in the sodium-free medium.

With degenerating nerves the effect of the lack of sodium develops qualitatively in the same manner in which it develops with normal nerves. Degenerating nerve fibers, however, become inexcitable in a sodium-free medium earlier than normal fibers. The recovery of the excitability in Ringer's solution takes place in much the same manner in normal and in degenerating nerve fibers.

The loss of excitability during Wallerian degeneration is a process that develops simultaneously, or practically so, throughout the entire length of the fibers. The nerve fibers retain a great deal of functional ability throughout the several days which precede the onset of inexcitability and then suddenly become inexcitable.
THE METAMORPHOSIS OF HEMOGLOBIN IN THE BULLFROG
Authors: Riggs Austen
Published: May 2004

1. Tadpole and adult hemoglobin do not differ significantly in molecular weight. The molecular weight of both is in the neighborhood of 68,000.

2. Heme-heme interaction as measured by the value of n in Hill's equation is virtually the same—about 2.8—in both tadpole and adult.

3. There appears to be no significant effect of pH upon the oxygen equilibrium of tadpole hemoglobin, in contrast to large Bohr and reverse Bohr effects in the adult. This is taken to mean that during metamorphosis acid groups of globin become sensitive to the oxygenation of heme by some change in the mode of linkage between heme and globin.

4. The oxygen affinity of tadpole hemoglobin is about seven times as great as that of the adult at pH 6 and twice as great at pH 9.
ON THE EXISTENCE OF A GRADIENT OF SENSITIVITY TO THE LACK OF SODIUM IN THE SPINAL ROOTS OF THE BULLFROG
Authors: Lorente de Nó R.
Published: May 2004

The Et class of fibers includes fibers of Gasser's d.r. C group.

The fibers of the dorsal root are more sensitive to the effect of lack of sodium than are the fibers of the ventral root.

In the two roots there is a gradient of sensitivity to the lack of sodium, which is such that in all the root fibers the sensitivity decreases with increasing distance from the spinal cord. The gradient continues in the trunk up to about 10 to 12 mm. peripheral to the trunk-roots margin. No comparable gradient of sensitivity to the lack of sodium has been observed in the rest of the nerve trunk.

The gradient of sensitivity to the lack of sodium has no relationship to the anatomical distribution of the epineurium.

As a working hypothesis it is suggested that the gradient of sensitivity to the lack of sodium is one aspect of a transitional gradient that serves to establish a gradual change between the properties that the axons have inside the spinal cord and the properties that they have inside the nerve trunks.

Details are given of the temporal course of the loss of excitability by root fibers deprived of sodium. It is suggested that sodium is present in the nerve fibers, in 2 forms, loosely and tightly bound sodium and that loss of loosely bound sodium is sufficient to render the nerve fibers unable to conduct impulses. If the rate of loss of loosely bound sodium is decreased, conversion of tightly bound into loosely bound sodium may temporarily restore the excitability of the nerve fibers.
ON THE EFFECT OF AMMONIUM AND LITHIUM IONS UPON FROG NERVE DEPRIVED OF SODIUM
Authors: Gallego A. , Lorente de Nó R.
Published: May 2004

An analysis has been made of the effect of ammonium and of lithium ions upon frog nerve deprived of sodium.

Ammonium ions cannot substitute for sodium ions and restore the excitability of the nerve fibers; nor can they increase the L fraction of the membrane potential and the efficiency of the nerve reaction. Certain observations, however, indicate that the presence of ammonium ions outside the nerve fibers may delay the development of inexcitability in a sodium-free medium of nerve fibers restored by a moderate amount of sodium ions.

Lithium ions can substitute for sodium and restore to nerve fibers of the A and C groups the ability to conduct impulses; the effect upon B fibers has not been investigated. Lithium cannot substitute for sodium in the role that sodium plays in the creation of the L fraction and in the establishment of the nerve reaction. In this respect lithium and sodium have opposite effects. This fact establishes an important difference between the two physiological responses that the nerve fibers can produce, the nerve impulse and the nerve reaction.

With untreated nerve the depolarization of nerve by lithium ions at high concentrations is preceded by a phase of hyperpolarization; with nerve deprived of sodium the depolarization begins without delay.
SEPARATION AND ASSAY OF LYSINS AND LYSIN-INHIBITOR COMPLEXES IN BLOOD AND TISSUES
Authors: Ponder Eric
Published: May 2004

1. A process of extraction and assay, which combines the features of several existing methods, is described for the lytic materials which can be obtained from blood, plasma, serum, and tissues. At least two alcohol-soluble substances, one ether-soluble ("soap-like") and the other insoluble in ether in the cold ("lysolecithin-like"), can be obtained from preincubated blood, plasma, or serum. The hemolytic activity (or concentration) of the soap-like lysin obtained from blood is greater than that of the lysolecithin-like substance, but for plasma and serum the reverse is true, i.e. the red cells are involved in the production of the soap-like lysin, and probably supply some of it when acted upon by enzymes contained in plasma and serum. Preincubation of the blood or plasma increases the yield of lysin two- or threefold, and small quantities of both soap-like and lysolecithin-like lysins can be obtained from unpreincubated blood or plasma.

2. The soap-like lysins obtained from preincubated mouse liver are some 5 to 15 times as active as, or occur in some 5 to 15 times the concentration of, those obtained from blood or plasma. The lysolecithin-like lysins of preincubated liver are about twice as active as, or occur in about twice as great concentration of, those obtained from blood. Because of the shape of the time-dilution curve for these lysins, the relations between their activities, or concentrations, are often quite different from those which one would anticipate if one were to consider only the times required for the production of hemolysis.

3. Paper chromatography can be used to separate the soap-like and the lysolecithin-like lysins obtainable from small quantities of preincubated mouse liver homogenates or preincubated mouse blood. The presence of lysins is detected by their effect on the red cells of a suspension as it wets the paper. Various technical procedures for separating lytic components and for demonstrating that they move on the paper along with protein components are described.

4. Paper strip electrophoresis can be used to show that the supernatant fluid of a preincubated mouse liver homogenate contains at least two protein components and at least two lytic components, not very closely associated in their electrophoretic behavior.

5. Observations on the physical nature of the alcohol- and ether-soluble lysin point to its having a soap-like character. Its activity, as well as that of the lysolecithin-like lysin, is inhibited by cholesterol, by lecithin, and by various fractions of serum. Some of these effects have been studied quantitatively. The most inhibitory of the protein fractions are those which contain lipoproteins; i.e., II + III and IV + V.
THE CYTOCHROME C OXIDASE OF THE HOUSE FLY, MUSCA DOMESTICA L
Authors: Sacktor Bertram
Published: May 2004

1. Insoluble and "soluble" forms of cytochrome c oxidase were prepared from house flies by methods described for mammalian tissue. A 4.5-fold purification was accomplished by preparing the enzyme in insoluble form (as compared with a crude water brei). The oxidase in "soluble" form was purified 20.0-fold.

2. The absorption spectrum of the "soluble" preparation from flies was similar to that from mammalian tissue, and indicated the presence of cytochromes a + a3 and b. In contrast with the corresponding mammalian enzymes these components were not separable by the existing techniques.

3. The Soret peak seen at 440 mµ and the alpha peak at 600 mµ were due. primarily to cytochromes a3 and a, respectively.

4. The oxidase activity of whole house flies was comparable with that of rat abdominal muscle. In both organisms, this activity was inhibited by cyanide to approximately the same extent.

5. The optimum buffer concentration for oxidase activity, as measured spectrophotometrically, was approximately 0.02 to 0.06 M. This is in agreement with results obtained for mammalian enzyme, as measured both manometrically and spectrophotometrically.

6. The present study has demonstrated the following components of the cytochrome system in house flies: b, c, a, and a3.
THE ALLEGED OCCURRENCE OF ADRENALIN IN THE MEALWORM
Authors: Gregerman Robert I. , Wald George
Published: May 2004

Wense has reported the isolation of crystalline adrenalin from larvae of the beetle Tenebrio molitor. An attempt to repeat his procedures failed to yield any evidence of adrenalin. Analysis of mealworm extracts by paper chromatography and colorimetric means also yielded no indication of adrenalin, though adrenalin added to mealworms can be detected by these procedures in amounts less than 1 mg. per 100 gm. Mealworm extracts reveal on the paper chromatogram the presence of two other orthodiphenols, neither of which appears to be dopa but which may be 3,4-dihydroxyphenyllactic acid and 3,4-dihydroxyphenylacetic acid, compounds recently isolated elsewhere from this organism.
PHYSICOCHEMICAL CHARACTERIZATION OF PITUITARY FOLLICLE-STIMULATING HORMONE
Authors: Li Choh Hao , Pedersen Kai O.
Published: May 2004

The physiochemical characteristics of the follicle-stimulating hormone (FSH) from whole sheep pituitary glands have been studied. The hormone behaves as a single protein in electrophoresis, diffusion, and ultracentrifugation. It has an isoelectric point at pH 4.5 and a molecular weight of 67,000 and contains 1.23 per cent hexose and 1.51 per cent hexosamine. The amino acid composition has also been determined in large part. The stability of the hormone to acid and heat has been investigated.
UPTAKE OF DEUTERIUM INTO PROTEINS OF FERTILIZED AND UNFERTILIZED ARBACIA EGGS SUSPENDED IN HEAVY WATER
Authors: Hoberman Henry D. , Metz Charles B. , Graff Jack
Published: May 2004

When fertilized and unfertilized eggs of Arbacia punctulata are suspended in heavy water, deuterium is incorporated into stable positions in the egg proteins. The rate of incorporation of the isotope is considerably greater in fertilized than in unfertilized eggs, and is accelerated at the time of formation of the blastula. The result of calculation of the maximum deuterium concentration which would be reached on complete turnover indicates that at least one out of every ten stably bound hydrogen atoms of the egg proteins is a deuterium atom. This has been interpreted as evidence that at the time of formation of the sea urchin blastula and in the period of development which follows, synthesis and breakdown are simultaneous processes leading to the redistribution of amino acids among the egg proteins.