bluuebunny/crossref_metadata_2025 huggingface dataset:
PREPARATION, PURIFICATION, AND PROPERTIES OF E. COLI VIRUS T2
Authors: Herriott Roger M. , Barlow James L.
Published: May 2004

1. A method for the preparation of 8 to 10 liter quantities of T2 virus lysates, titering 2 to 5 x 1011 infectious units per ml. has been described.

2. Procedures have been developed for the concentration and purification of virus to a high specific infectivity. No fractionation procedure of the several used succeeded in further raising the specific infectivity of these purified preparations.

3. Some of the general properties of the better preparations have been determined. They exhibited titers of 2 x 1015 infective units per gm. of material or 1.2 x 1016 per gm. of nitrogen.

4. A study of the distribution of nitrogen among the various fractions of the virus showed that about 6 per cent of the total nitrogen is soluble in 4 per cent trichloracetic acid; that the protein nitrogen is about 40 per cent of the total and the nucleic acid nitrogen is 53 per cent. At least 96 per cent of the total phosphorus is in the nucleic acid fraction. Less than 0.5 per cent quantities of lipid and PNA were found.
THE ACTION OF VENOM AND PROTEOLYTIC ENZYMES ON THE NON-SPECIFIC INHIBITOR OF HYALURONIDASE
Authors: Hadidian Z.
Published: May 2004

1. It has been shown that a number of proteolytic enzymes and snake venom, in relatively small amounts, and within a wide range of pH variation, will restore hyaluronidase activity after its inhibition by serum.

2. The known properties of the venom protease are found to be identical with those of Haas' "proinvasin I." It is concluded that the protease of the venom offers adequate explanation for the effects previously attributed to "proinvasin I."

3. Proteolytic activity is found in hyaluronidase preparations of bovine origin and is considered to be responsible for the reversal of inhibition of hyaluronidase by serum.
MODIFICATION BY TEMPERATURE OF CONDUCTION AND GANGLIONIC TRANSMISSION IN THE GASTROPOD NERVOUS SYSTEM
Authors: Turner R. S.
Published: May 2004

The pedal ganglia of the terrestrial gastropod Ariolimax contain junctions between nerve fibers which are shown to be preferential points of fatigue and which exhibit facilitation (summation) of preganglionic impulses to produce a postganglionic spike. These characteristics in conjunction with others previously reported (reversible susceptibility to nicotine, convergence of preganglionic impulses, and inhibition of transmission through setting up a refractory state in the postganglionic fiber) are considered sufficient to indicate synaptic transmission in the pedal ganglia.

The mean conduction velocity of the fastest fibers in the pedal nerves is 0.52 meter per second for preganglionic and 0.50 meter per second for postganglionic fibers at 7.56°C. The conduction rates at 21.76°C. are respectively 0.80 meter per second and 0.83 meter per second. The mean ganglionic delay is 0.033 second at 7.56°C. and 0.019 second at 21.76°C. The mean Q10's for conduction velocity are thus 1.37 for preganglionic and 1.42 for postganglionic fibers. The mean Q10 for ganglionic delay is 1.49. If the assumption is made that the Q10 for ganglionic delay is that of a limiting reaction, this figure then represents a value below which the Q10 for synaptic delay is statistically improbable.
ENZYME FORMATION IN NON-VIABLE CELLS
Authors: Baron L. S. , Spiegelman S. , Quastler H.
Published: May 2004

An attempt has been made to find conditions which would completely dissociate viability from capacity to synthesize enzymes in yeast cells. The only lethal agent or condition found which yielded complete dissociation was x-irradiation. Dosages leading to 99.9 per cent lethality and greater exhibited no inhibitory action on the capacity of the treated suspensions to synthesize maltozymase and galactozymase. Such suspensions also retained their ability to assimilate externally supplied nitrogen and employ it in the synthesis of enzyme.
THE CONVERSION OF FIBRINOGEN TO FIBRIN
Authors: Shulman Sidney , Katz Sidney , Ferry John D.
Published: May 2004

1. Fibrin clots prepared in the absence of calcium can be dissolved in solutions of lithium chloride and bromide and sodium bromide and iodide, as well as of guanidine hydrochloride and urea. These salts do not denature fibrinogen under the same conditions of concentration, temperature, and time. Sedimentation experiments on the fibrin solutions show in each case a single sharp peak with a sedimentation constant close to that of fibrinogen.

2. At lower concentrations, these salts inhibit the clotting of fibrinogen by thrombin, but in the case of lithium bromide and sodium iodide, at least, allow an intermediate polymer to accumulate whose sedimentation constant is close to that of the polymer observed in systems inhibited by hexamethylene glycol or urea.
THE EFFECT OF SODIUM AND POTASSIUM IONS ON THE IMPEDANCE CHANGE ACCOMPANYING THE SPIKE IN THE SQUID GIANT AXON
Authors: Grundfest Harry , Shanes Abraham M. , Freygang Walter
Published: May 2004

Decrease of the sodium concentration of the medium depresses both the spike and the associated impedance change in almost identical fashion. Elevation of the potassium level also depresses both phenomena, but affects the impedance change more than the spike; it slows the return to the initial impedance level. The effects on the threshold to brief square waves are also described. These results appear largely accounted for by the observations of Hodgkin and Huxley with the voltage clamp technique and by their recent hypothesis as to nature of the spike processes.
THE COMBINATION BETWEEN HEMOLYSINS AND RED CELLS OR GHOSTS, AS STUDIED WITH A RADIOACTIVE LYSIN AND WITH NEW COLOR REACTIONS
Authors: Ponder Eric , Ponder Ruth V. , Anderson R. Christian
Published: May 2004

The quantity of a radioactive hemolysin, sodium dodecyl sulfonate-S35, taken up by red cells from concentrations too small to produce hemolysis varies with the lysin concentration, and does so in a way which can be described by an adsorption isotherm. Attempts to use color reactions or surface tension measurements to determine the quantity of digitonin, saponin, and the bile salts taken up by red cells from hypolytic concentrations have failed, principally because chromogenic, and also surface-active, substances are liberated from the cells when the lysin is added. Color reactions with the anthrone reagent show that digitonin and saponin are both taken up by or fixed to red cell ghosts; the extent of the uptake, however, is uncertain, again because of the liberation of chromogenic substances.

Comparison of the results of the various methods which measure the apparent amount of lysin fixed, or utilized in reactions between lysins and red cells or ghosts show discrepancies between results given by direct methods (measurement of radioactivity or of color) and indirect methods (addition of a second population after lysis of a first, and dependence of the position of the asymptote of the time-dilution curve on the number of red cells). The discrepancies are traceable to the inhibitory effects of substances liberated from the red cells or ghosts.

The ease with which a lysin, once taken up by red cells, can be detached by diluting the system determines the extent to which the hemolytic reaction is "progressive," but has no observed connection with the quantity taken up in the first place. There is now ample evidence that lysis in systems containing simple hemolysins is a process involving two stages in time and two phases, and that it is usually complicated by reactions between the hemolysin and liberated inhibitory material.
POTASSIUM UPTAKE BY THE DOG ERYTHROCYTE
Authors: Frazier Howard S. , Sicular Arthur , Solomon A. K.
Published: May 2004

The inward transport of potassium by separated dog erythrocytes has been studied at concentrations of potassium in the medium from 2.9 to 25.0 m.eq./liter and at 38.0 and 33.0°C. At the physiological concentration of external potassium (4.06 m.eq./liter medium), the inward potassium flux is 0.11 m.eq./liter cells hour and the glucose consumption is 2.0 mM/liter cells hour. The dependence of potassium influx on extracellular potassium concentration is given by the following equation,

K influx (m.eq./liter cells hour) = 0.028 [K]amb. – 0.003

in which [K]amb. refers to the potassium concentration in the medium. In a single 93 hour experiment, 94 per cent of the intracellular potassium was exchanged at an apparently uniform rate. The average apparent activation energy for the process is 7,750 calories ± 2,000 calories/mol and there is some indication that the apparent activation energy of inward K transport decreases with increasing external K concentration.
OLFACTORY RESPONSES OF BLOWFLIES TO ALIPHATIC ALDEHYDES
Authors: Dethier V. G.
Published: May 2004

The response of the blowfly Phormia regina to stimulation by aldehydes in the vapor phase has been studied by means of a specially designed olfactometer. The median rejection threshold and the maximum acceptance threshold were selected as criteria of response. For both acceptance and rejection the distribution of thresholds in the population is normal with respect to the logarithm of concentration. When thresholds are expressed as molar concentrations, the values decrease progressively as chain length is increased. There is no attraction beyond decanal and no rejection beyond dodecanal. When thresholds are expressed as activities, most members of the aldehyde series are approximately equally stimulating at rejection and equally stimulating at acceptance. The relationship is most exact over the middle range of chain lengths. There is a tendency for the terminal members to stimulate at higher activities. These relationships are in close agreement with those which were found earlier to apply to the normal aliphatic alcohols. The similarity between the relative actions of the members of the two series suggests that the relation of equal olfactory stimulation at equal thermodynamic activities by homologous aliphatic compounds at least for homologues of intermediate chain length may be of rather general application in olfaction.
ON THE ROLE OF THE SPINAL AFFERENT NEURON AS A GENERATOR OF EXTRACELLULAR CURRENT
Authors: Rudin Donald O. , Eisenman George
Published: May 2004

The prediction that a system of currents flows between the dorsal column and the dorsal root due to differences in their after-potentials was found to be consistent with the experimental findings. The form, magnitude, duration, and sign of the electrotonic component DRα fulfill the requirements of the postulated system.

A contribution of tract after-potentials to the evoked potential of intramedullary structures is indicated.

It is a conclusion of this and previous studies that profound changes occur in certain membrane properties of myelinated primary afferent axons as they penetrate the central nervous system. The working concept of abrupt intraaxonal junctional regions is therefore justifiable.
THE MERCURY-HYDROGEN PEROXIDE SYSTEM AS AN ANALOGUE OF NERVOUS TRANSMISSION
Authors: Vis V. A.
Published: May 2004

The construction and behavior of a system exhibiting all-or-nothing propagation of an electrochemical disturbance are described. Detailed measurements of the distribution of electric current and potential are given and the device is compared with nerve and with the Lillie model in respect to structure, electrical and chemical activity, and energy relationships.
HEXOKINASE ACTIVITY FROM EGGS OF THE SEA URCHIN ARBACIA PUNCTULATA
Authors: Krahl M. E. , Keltch A. K. , Walters C. P. , Clowes G. H. A.
Published: May 2004

1. The hexokinase activity of homogenates of eggs and embryos of the sea urchin Arbacia punctulata has been measured. Expressed as micrograms glucose consumed at 20°C., per hour per milligram of protein the following values were obtained: unfertilized eggs, 67; fertilized eggs, 72; 24 hour plutei, 94; 48 hour plutei, 226. The concentration of the enzyme in the eggs is small and may be calculated to be about 0.001 per cent of the dry weight of unfertilized eggs.

2. The hexokinase activity of the egg homogenate was virtually all recovered in the supernatant fraction when the homogenate was centrifuged at 20,000 x g for 30 minutes and was found to have the following properties: The concentrations for half maximal hexokinase activity with various substrates were, approximately: Glucose, 0,00003 M; fructose, 0.00075; mannose, 0.00007; 2-desoxyglucose, 0.00025. The relative rates of phosphorylation of various sugars by the supernate fraction when saturated with substrate were, approximately: Glucose, 1.0; mannose, 1.2; fructose, 1.8; 2-desoxyglucose, 2.0; glucosamine, 0.6. Adenosinediphosphate and glucose-6-phosphate inhibited the enzyme. No evidence for more than one hexokinase in the Arbacia extracts was found.
INTERACTIONS BETWEEN MAGNESIUM, PYROPHOSPHATE, AND THE CONTRACTILE ELEMENTS
Authors: Bozler Emil
Published: May 2004

1. If glycerol-extracted muscle fibers are alternately immersed in solutions of inorganic pyrophosphate (PP) or ethylenediamme tetraacetate (EDTA) and KCl two to three times, PP no longer increases extensibility. The original condition is restored by solutions containing Mg. EDTA prevents completely the softening action of PP, but has no effect in the presence of an excess of Mg. These observations are explained by assuming that PP and EDTA remove bound Mg. Evidently PP has no softening action without Mg.

2. If PP is washed out from muscle fibers by solutions containing Mg, the softening action of PP persists for many minutes, but washing out with KCl solution promptly abolishes the effect of PP. Also, if fibers which have been made refractory to PP are immersed into a solution of PP and then into a KCl solution free of PP for several minutes, the addition of MgCl2 alone increases extensibility. It is concluded that PP forms a complex with protein. The formation of this complex, however, has no influence on the mechanical properties, unless Mg also is present.

3. In the presence of PP and Mg the viscous resistance of muscle fibers drops with diminishing temperatures.
DISTRIBUTION OF ESTERASE IN GASTRIC MUCOSA
Authors: Doyle W. L.
Published: May 2004

Sections of frozen-dried stomach mucosa of the rabbit cut at various levels from the surface were analyzed for esterase activity in relation to the proportions of cell types present. Aside from the fraction attributable to extracellular esterase all the esterase activity appears to be in proportion to the numbers of foveolar and neck mucous cells present in the sample.
CHROMATOGRAPHY OF BLOOD-CLOTTING FACTORS AND SERUM PROTEINS ON COLUMNS OF DIATOMACEOUS EARTH
Authors: Milstone J. H.
Published: May 2004

1. In batch adsorptions with prothrombin solutions, hyflo was the weakest adsorbent, standard super-cel intermediate, and filter-cel strongest. Of these three grades of diatomaceous earth, hyflo has the smallest surface area per gram and filter-cel the largest. In parallel breakthrough experiments, a column of standard super-cel had a capacity almost six times that of a hyflo column.

2. After partial removal of impurities by diatomaceous earth, prothrombin preparations contained less thrombokinase, were more stable, and displayed less tendency to form thrombin "spontaneously." Thrombokinase (or its precursor) was removed from a preparation of prothrombin by passage through a filter cake of standard super-cel. The specific activity of the prothrombin was increased; and 62 per cent of the activity was recovered.

3. Prothrombin was adsorbed from an ammonium sulfate solution at pH 5.26 by columns of hyflo or standard super-cel. When eluted by phosphate solutions, the protein moved down the columns more readily at higher pH and higher concentration of phosphate salts, within the pH range 5.0 to 6.6, and within the phosphate range 0.1 to 1.0 M.

4. Thrombin was adsorbed on a column of standard super-cel at pH 5.11. As successive eluents passed through the column, the thrombin emerged between two bands of impurities. The specific activity of the thrombin was raised; and 83 per cent of the activity was recovered.

5. With a column of standard super-cel, and with a series of eluents within the pH range 5.1 to 6.3, total serum proteins were separated into four major bands. About 94 per cent of the protein was recovered.
THE RELATIONSHIP BETWEEN CHLOROPHYLL AND THE CAROTENOIDS IN THE ALGAL FLAGELLATE, EUGLENA
Authors: Wolken J. J. , Mellon A. D.
Published: May 2004

1. We have obtained an action spectrum for chlorophyll formation in Euglena gracilis. This action spectrum is similar to the absorption spectrum of protochlorophyll. However, efforts to isolate and identify this pigment have been unsuccessful.

2. Porphyrins have been extracted from both the normal and dark-adapted Euglena and a chlorophyll-free mutant.

3. The "action" spectra for chlorophyll and carotenoid synthesis have been found to almost coincide, indicating that the same porphyrin-like molecule may influence the synthesis of both pigments.

4. It is indicated that two porphyrin-like systems are in operation simultaneously, one concerned with carotenoid "removal" and another involved in carotenoid and chlorophyll synthesis.
THE ROLE OF A CONTAMINANT IN THROMBIN IN THE HUMAN PLASMIN ASSAY SYSTEM
Authors: Siegel Malcolm , Cliffton Eugene E.
Published: May 2004

Many of the anomalous results obtained in the fibrinolytic assay of human plasmin systems were shown to be simply explained if bovine plasminogen had been introduced into the assay system on the addition of thrombin. Experimental investigation of the proteolytic and fibrinolytic activity of systems containing plasmin and thrombin showed that enzyme activity was influenced by the presence and quantity of thrombin. The quantity of bovine plasminogen present as a contaminant in bovine fibrinogen was shown to be responsible for only 1/25th of the observed enhanced activity. Thrombin in the amounts commonly used for clotting contained sufficient proenzyme to account for all this activity. A highly purified thrombin preparation obtained from another laboratory, and thrombin purified in this laboratory by starch electrophoresis brought about no enhancement of activity. The material separated from thrombin by starch electrophoresis was shown to be enzymatically identical with bovine plasminogen and, on labelling with radioactive iodine, was shown to behave physically like bovine plasminogen. Several experiments reported in the literature were reinterpreted in the light of this observation.
NARCOSIS AND EMULSION REVERSAL BY INERT GASES
Authors: Sears Dewey F. , Fenn Wallace O.
Published: May 2004

Investigations of the effect of high pressures of Na (100 to 130 atmospheres) and of Ar (60 to 80 atmospheres) showed that these gases are effective in reversing the phases of an oil in water emulsion. Nitrous oxide did not cause reversal at pressures as high as 53 atmospheres nor did helium as high as 107 atmospheres. We found CO2 most effective in reversing the emulsions and attributed this to its chemical properties. It is suggested that these observations may help to explain the narcotic effects of inert gases.
THE PROTEIN COATS OR "GHOSTS" OF COLIPHAGE T2
Authors: Herriott Roger M. , Barlow James L.
Published: May 2004

A method of preparing the protein coats or ghosts of phage T2 is described along with proof that the lytic action is a property of the ghost.

An assay based on the lytic action toward host cells has been developed which permits a rapid evaluation of the number of ghosts with a reliability of ±15 per cent.

The antigenic and certain physicochemical properties of the ghost have been determined.
PERMEATION AND DIFFUSION OF K IONS IN FROG MUSCLE
Authors: Harris E. J.
Published: May 2004

The movements of tracer K and net changes of K have been measured in frog muscle. The quantities moving can be linearly related to the square root of the time after a delay of 4 to 30 minutes depending on the external K concentration. The slope of the uptake-t½ line is increased when the external K concentration is raised. The Q10 of the uptake is about 1.9 per unit t½. K uptake from 1 to 2 mM concentration is diminished by a factor of about 2 if strophanthin is applied. The output per unit t½ is increased by a factor of about 1.4 by strophanthin. Tetrabutylammonium substituted for 10 per cent of the Na in the medium causes a reversible slowing of K uptake and Na output. The rates of movement found in the tracer experiments can be used to calculate the net losses of K taking place in K-free or strophanthin-containing media. The results are interpreted on the basis of K movement being limited both by a resistive outer layer and by diffusion within a K-rich region. The internal diffusion constant is 10–11 to 10–10 cm.2 sec.–1 depending on the K concentration. The rate of movement of the K can be related to the electrochemical activity of the ion, the lability of the sites on which it is absorbed, and cation + anion pair diffusion within the cell. The surface resistance to K ions can be accounted for as the sum of a membrane resistance equal to that found by electrical methods and the resistance offered to the movement of K by an annulus sufficiently thick (ca. 3 µ) to accommodate the cell Na at a density equal to the mean density of cation within the cell through which K diffuses with the same diffusion constant as holds in the K-rich region. Na movement, if assumed to take place by diffusion from the annulus with diffusion constant equal to that for K ions, has a rate which agrees well with observed values. The influence of strophanthin and tetrabutylammonium on the ion movements is interpreted as being the result of these agents causing an expansion of the outer non-selective region, normally occupied mainly by Na, at the expense of the inner K-rich region.
STUDIES ON PROTEIN SYNTHESIS IN VITRO
Authors: Korner A. , Tarver H.
Published: May 2004

The release of radioactive amino acid from the particulate fractions separated from the prelabelled livers of rats by centrifugation has been studied under various conditions. Although pure fractions may not have been obtained, great differences in behavior were observed. In the mitochondria and nuclei dinitrophenol (10–4 M) causes an inhibition of release, but in microsomes the opposite effect is observed. When the incubation medium is fortified with ATP and phosphocreatine, release is inhibited. In microsomes and nuclei the inhibition proceeds to the extent that the incorporation of preformed radioactive amino acid occurs. Protein is synthesized at a rapid rate. In incubations longer than 1 hour there is always a release of radioactive amino acid. It is concluded from these results that the interpretation of release data from slices or systems such as those studied is impossible without further information concerning some of the unknown variables. The most important unknown is the specific activity of the "free" amino acid in the particulates and the effect of carrier amino acid in the medium of this specific activity.
RENAL TUBULAR TRANSPORT OF INORGANIC DIVALENT IONS BY THE AGLOMERULAR MARINE TELEOST, LOPHIUS AMERICANUS
Authors: Berglund Fredrik , Forster Roy P.
Published: May 2004

A characterization was attempted of the mechanisms involved in the tubular transport of inorganic divalent ions by the aglomerular kidney of Lophius, attention being paid particularly to the possible existence of transport maxima (Tm) and to competition for transport among related substances undergoing tubular excretion. Excretory rates of divalent ions in non-treated fish during standard laboratory conditions paralleled spontaneous changes in urine flow. Tm rates of excretion were reached for magnesium, sulfate, and thiosulfate with corresponding plasma levels of 2 to 5, 5 to 17, and 4 to 12 µM/ml. respectively. Elevation of magnesium chloride levels in plasma markedly depressed calcium excretion; sodium thiosulfate similarly depressed sulfate excretion. Experimental observations suggest the existence of a transport system for divalent cations separate from another for divalent anions. Within each transport system the ion with the higher excretion rate depressed competitively transfer of the other ion. Neither system was influenced by probenecid (benemid) in doses which markedly depressed the simultaneous excretion rate of p-aminohippuric acid.
RESPONSE OF POTASSIUM RETENTIVITY AND SURVIVAL OF YEAST TO FAR-ULTRAVIOLET, NEAR-ULTRAVIOLET AND VISIBLE, AND X-RADIATION
Authors: Bruce A. K.
Published: May 2004

Potassium retentivity and survival of yeast were studied after exposure to various kinds and conditions of irradiation. The radiations used were: 2537 A ultraviolet, 3500 to 4900 A long-ultraviolet and short visible, and 250 kvp1 x-rays. Both potassium retentivity and survival are decreased by these radiations. The dose-response of survival is about 16 times as sensitive as is potassium retentivity after 2537 A irradiation. Potassium retentivity is about twice as sensitive as survival after irradiation of 3500 to 4900 A. Survival after x-irradiation under aerobic conditions is five times as sensitive as potassium retentivity. Survival of cells irradiated with x-rays under anaerobic conditions was about half as sensitive as under aerobic conditions. The response of potassium retentivity to x-radiation at 25°C. under anaerobic conditions is only slightly affected below 160 kr, at which dose the slope abruptly increases to that obtained under aerobic conditions; lowering the temperature to 0°C. moves this point to about 300 kr. These differential effects are indicative of interaction of radiations with the yeast cell at sites that independently control survival and the retention of potassium.
THE SECRETION OF INERT GAS INTO THE SWIM-BLADDER OF FISH
Authors: Wittenberg Jonathan B.
Published: May 2004

The composition of the gas mixture secreted into the swim-bladders of several species of fish has been determined in the mass spectrometer. The secreted gas differed greatly from the gas mixture breathed by the fish in the relative proportions of the chemically inert gases, argon, neon, helium, and nitrogen. Relative to nitrogen the proportion of the very soluble argon was increased and the proportions of the much less soluble neon and helium decreased. The composition of the secreted gas approaches the composition of the gas mixture dissolved in the tissue fluid. A theory of inert gas secretion is proposed. It is suggested that oxygen gas is actively secreted and evolved in the form of minute bubbles, that inert gases diffuse into these bubbles, and that the bubbles are passed into the swim-bladder carrying with them inert gases. Coupled to a preferential reabsorption of oxygen from the swim-bladder this mechanism can achieve high tensions of inert gas in the swim-bladder. The accumulation of nearly pure nitrogen in the swim-bladder of goldfish (Carassius auratus) is accomplished by the secretion of an oxygen-rich gas mixture followed by the reabsorption of oxygen.
THE PRODUCTION OF HYDROGEN PEROXIDE BY HIGH OXYGEN PRESSURES
Authors: Gilbert Daniel L. , Gerschman Rebeca , Ruhm K. Barclay , Price William E.
Published: May 2004

Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH.
THE CATION CONTENT OF PHOSPHOLIPIDES FROM SWINE ERYTHROCYTES
Authors: Kirschner Leonard B.
Published: May 2004

Phospholipides from swine erythrocytes were isolated and separated into four reproducible fractions. One of the fractions seems to be pure phosphatidylserine. The others are almost certainly not single compounds, although the analytical data indicate that they represent mixtures considerably simpler than the parent mixture extracted from the cells.

All four fractions contained Na+ and K+, but very little Ca2+. Sodium was the predominant cation in two of the fractions under all conditions although the major intracellular cation was potassium. In the other two fractions the ratio Na/K varied with the extraction procedure largely because the quantity of K+ seemed to depend on the solvent system used. There appear to be reasons to believe that the entire system of phospholipides binds Na+ preferentially. In addition, it was observed that the quantity of Na+ found in the lipide extracts varied when the extrusion of Na+ from the cells was made to vary. Both of these observations are consistent with the possibility that the phospholipides play some part in the extrusion of Na+ from these cells.
THE INFLUENCE OF HIGH HYDROSTATIC PRESSURE ON COCAINE AND VERATRINE ACTION IN A VERTEBRATE NERVE
Authors: Gershfeld Norman L. , Shanes Abraham M.
Published: May 2004

The application of high hydrostatic pressure to toad sciatic nerve causes a gain in sodium and a loss of potassium which are not affected by cocaine. However, cocaine action is enhanced by high pressure when counteracting veratrine depolarization and when blocking the action potential. Various effects of elevated pressure on the after-potentials are presented and the role of ions in these processes is discussed.
THE CONTROL OF MEMBRANE IONIC CURRENTS BY THE MEMBRANE POTENTIAL OF MUSCLE
Authors: Jenerick Howard
Published: May 2004

Comparisons between electrotronic potentials and certain predicted curves allow the identification of the membrane potential at which the sodium and potassium currents are switched on in frog sartorius. The activation potentials (the membrane potentials at which the ionic currents are great enough to be resolved by the method) are functions of the resting potential and time but not of ionic concentration. In the normal fiber, the activation potential for sodium lies nearer the resting potential and depolarizations set off sodium currents and action potentials. Below a resting potential of 55 to 60 mv. sodium activation is lost and conduction is impossible. A tenfold increase of calcium concentration lowers (moves further from the resting potential) the sodium activation potential by 20 to 25 mv. whereas the potassium activation potential is lowered by only 15 mv. Certain consequences of this are seen in the behavior of the muscle cell when it is stimulated with long duration shock.
Studies on the Relation between the Pigment Migration and the Sensitivity Changes during Dark Adaptation in Diurnal and Nocturnal Lepidoptera
Authors: Bernhard C. G. , Ottoson D.
Published: May 2004

The functional significance of the pigment migration in the compound insect eye during dark adaptation has been studied in diurnal and nocturnal Lepidoptera. Measurements of the photomechanical changes were made on sections of eyes which had been dark-adapted for varying periods of time. In some experiments the sensitivity changes during dark adaptation were first determined before the eye was placed in the fixation solution. No change in the position of the retinal pigment occurred in Cerapteryx graminis until the eye had been dark-adapted for about 5 minutes. The start of the migration was accompanied by the appearance of a break in the dark adaptation curve. During longer periods of dark adaptation the outward movement of the pigment proceeded in parallel with the change in sensitivity, the migration as well as the adaptive process being completed within about 30 minutes. In the diurnal insects chosen for the present study (Erebia, Argynnis) the positional changes of the retinal pigment were insignificant in comparison with the movement of the distal pigment in Cerapteryx graminis. On the basis of these observations the tentative hypothesis is put forward that the second phase of adaptive change in nocturnal Lepidoptera is mediated by the migration of the retinal pigment while the first phase is assumed to be produced by the resynthesis of some photochemical substance. In diurnal insects which have no appreciable pigment migration the biochemical events alone appear to be responsible for the increase in sensitivity during dark adaptation.
The Effect of Temperature on the Uptake of Radiosulfate by Rat Renal Tissue from Radiosulfate-Containing Solutions in Vitro
Authors: Deyrup Ingrith J. , Davies R. E.
Published: May 2004

Kidney cortex slices incubated in vitro at 0°C. accumulate radiosulfate from the incubation medium. This process differs from the previously described uptake of radiosulfate by renal tissue incubated at 38°C., for instance, in the lesser sensitivity of the uptake at 0°C. to differential effects of Na+ as compared with K+ ions, and of sucrose as compared with glucose. Phlorizin inhibits radiosulfate accumulation at 0°C., whereas it enhances the uptake at 38°C. Effects of the cations K+ and Na+ and of phlorizin at temperatures intermediate between 0° and 38°C. have been studied. Parallels have been noted between the accumulative processes for radiosulfate of kidney slices maintained at 0°C. and of mitochondria isolated from rat liver and kidney cortex. These similarities may be attributed to an important role of radiosulfate uptake by mitochondria in slice accumulation of radiosulfate in the cold.
Electrophysiology of the Insect Dorsal Ocellus
Authors: Ruck Philip
Published: May 2004

Dorsal ocelli are small cup-like organs containing a layer of photoreceptor cells, the short axons of which synapse at the base of the cup with dendritic terminals of ocellar nerve fibers. The ocellar ERG of dragonflies, recorded from the surface of the receptor cell layer and from the long lateral ocellar nerve, contains four components. Component 1 is a depolarizing sensory generator potential which originates in the distal ends of the receptor cells and evokes component 2. Component 2 is believed to be a depolarizing response of the receptor axons. It evokes a hyperpolarizing postsynaptic potential, component 3, which originates in the dendritic terminals of the ocellar nerve fibers. Ocellar nerve fibers in dragonflies are spontaneously active, discharging afferent nerve impulses (component 4) in the dark-adapted state. Component 3 inhibits this discharge. The ERG of the cockroach ocellus is similar. The main differences are that component 3 is not as conspicuous as in the dragonflies and that in most cases ocellar nerve impulses appear only as a brief burst at "off." In one preparation a spontaneous discharge of nerve impulses was observed. As in the dragonflies, this was inhibited by illumination.
Electrophysiology of the Insect Dorsal Ocellus
Authors: Ruck Philip
Published: May 2004

The ERG of the dragonfly ocellus has been analyzed into four components, two of which originate in the photoreceptor cells, two in the ocellar nerve fibers (Ruck, 1961 a). Component 1 is a sensory generator potential, component 2 a response of the receptor axons. Component 3 is an inhibitory postsynaptic potential, component 4, a discharge of afferent nerve impulses in ocellar nerve fibers. Responses to flickering light are examined in terms of this analytic scheme. It has been found that the generator potential can respond to higher rates of flicker—up to 220/sec.—than can the receptor axon responses, the postsynaptic potential, or the ocellar nerve impulses. The maximum flicker fusion frequency as measured by fusion of the ERG is that of the sensory generator potential itself.
Some Cation Interactions in Muscle
Authors: Sjodin R. A.
Published: May 2004

It has been possible to treat potassium, rubidium, and cesium ion entry into frog sartorius muscle by the use of a model which assumes a limited number of sites at the cell surface. The ion concentration in an outer surface layer is regarded as the main factor determining the rate of inward movement. It is supposed that the concentration of ions in the external solution is effective in promoting inward movement only to an extent determined by the fraction of sites occupied. Equations are derived from the model which fit the inward flux versus applied concentration curves experimentally determined for the three ions. The ions were found to compete for the postulated sites in various bi-ionic mixtures, the competition being satisfactorily described by equations derived from the model. The constants assigned to each ion remain invariant and independent of gradients in electrochemical potential. The order of decreasing exchange rate found is K > Rb > Cs. The order of decreasing site affinity found is Rb > K > Cs which is the same order as that observed for the ion selectivity deduced from analytical measurements of cation preference after equilibration in various equimolal mixtures (Lubin and Schneider (21)). The manner in which such a model might affect the application of a theory which assumes electrical driving forces as well is discussed.
Permeability of Frog Skeletal Muscle Cells to Choline
Authors: Renkin Eugene M.
Published: May 2004

Using choline-methyl-C14 as a tracer, it has been shown that choline+ penetrates into the cells of resting frog skeletal muscle at a rate similar to that of Na+, and that it escapes from these cells much more slowly than does Na+. Some implications of these findings are discussed.
The Ionic Mechanisms of Hyperpolarizing Responses in Lobster Muscle Fibers
Authors: Reuben J. P. , Werman R. , Grundfest H.
Published: May 2004

Lobster muscle fibers develop hyperpolarizing responses when subjected to sufficiently strong hyperpolarizing currents. In contrast to axons of frog, toad, and squid, the muscle fibers produce their responses without the need for prior depolarization in high external K+. Responses begin at a threshold polarization (50 to 70 mv), the potential reaching 150 to 200 mv hyperpolarization while the current remains constant. The increased polarization develops at first slowly, then becomes rapid. It usually subsides from its peak spontaneously, falling temporarily to a potential less hyperpolarized than at threshold for the response. As long as current is applied there can be oscillatory behavior with sequential rise and subsidence of the polarization, repeating a number of times. Withdrawal of current leads to rapid return of the potential to the resting level and a small, brief depolarization. Associated with the latter, but of longer duration, is an increased conductance whose magnitude and duration increase with the antecedent current. Hyperpolarizing responses of lobster muscle fibers are due to increased membrane resistance caused by hyperpolarizing K inactivation. The oscillatory characteristic of the response is due to a delayed superimposed and prolonged increase in membrane permeability, probably for Na+ and for either K+ or Cl-. The hyperpolarizing responses of other tissues also appear to result from hyperpolarizing K inactivation, on which is superimposed an increased conductance for some other ion or ions.
Preliminary Investigations on the Action of Pepsin on Human Pituitary Growth Hormone
Authors: Li Choh Hao
Published: May 2004

A slight modification of the original procedure for the isolation of human pituitary growth hormone has been described. The purity of the preparation was further examined by chromatography on carboxymethylcellulose, zone electrophoresis on starch, and electrodialysis. The hormone was found to be stable in a pH 7.0 solution at 100°C and in 10 M urea at 25°C. Digestion with pepsin to an extent of 40 per cent did not diminish the biological activities of the hormone. Bioassays of an active core derived from such digests exhibited essentially the same specific growth-stimulating activity in the hypophysectomized rat and crop sac stimulation in the pigeon. It was concluded that the integrity of the protein is not required for the activity of human growth hormone.
The Development of the Rhabdom and the Appearance of the Electrical Response in the Insect Eye
Authors: Eguchi Eisuke , Naka Kén-Ichi , Kuwabara Masutaro
Published: May 2004

Electron microscopic studies on the development of the rhabdom in the compound eye of the silkworm moth and pupa (Bombyx mori) were carried out in parallel with the recording of the electrical response to photic stimulation. No electrical response to photic stimulation was recorded from the pupal compound eye which had no trace of differentiation of the rhabdom. With the differentiation of development of the rhabdom in the pupal compound eye, electrical responses could be recorded, and the amplitude of such electrical responses increased with the progress of development of the rhabdom. These observations suggest that the rhabdom is probably the site of the photochemical reaction which leads to the generation of the slow retinal action potentials.
Diffusion Barriers in the Squid Nerve Fiber
Authors: Villegas Raimundo , Caputo Carlo , Villegas Leopoldo
Published: May 2004

The squid nerve barriers are formed by (a) the axolemma (membrane of the axon proper), a membrane 80 Å thick perforated by cylindrical pores 4.0 to 4.5 Å radius, and (b) the Schwann layer, constituted of numerous cells forming a layer one cell thick, crossed by 60 Å wide slit channels. If a molecule present in the axoplasm has to reach the extraneural space, it has to pass (a) the pores, and (b) the channels, in series, and the diffusion rate will depend on the effective diffusion areas per unit path length, Apd/Δx for the axolemma, and Acd/Δx for the Schwann layer. By addition, And/Δx, the transneural effective area for diffusion per unit path length is obtained. The diffusion rates of C14-ethylene glycol (2.2 Å radius), and C14-glycerol (2.8 Å radius) were measured. The diffusion rate of H3-labeled water (1.5 Å radius) has been previously determined. The results expressed in terms of And/Δx (mean values ± SD, referred to 1 cm2 of nerve surface) are 5.3 ± 1.4 cm for water, 2.5 ± 0.4 cm for ethylene glycol, and 0.29 ± 0.03 cm for glycerol. Theoretical values for And/Δx of 2.5 and 0.83 cm for ethylene glycol and glycerol have been calculated. The agreement between the theoretical values for And/Δx and the experimental ones supports the diffusion barrier model described above.
Transient Responses to Sudden Illumination in Cells of the Eye of Limulus
Authors: Fuortes M. G. F. , Poggio G. F.
Published: May 2004

Responses recorded from visual cells of Limulus (presumably eccentric cells) following abrupt and maintained illumination consist of depolarization with superimposed spikes. Both the depolarization and the frequency of firing are greater at the beginning of the response than later on. Frequency of firing decreases with time also during stimulation with constant currents, but the decay is then less than it is during constant illumination. Early and steady-state responses do not increase in the same proportion following illumination at different intensities. Membrane conductance is higher during the early peak of the response than in steady state. Early and late potential changes appear to tend to the same equilibrium value. The results support the assumptions that: (a) discharge of impulses is the consequence of depolarization of a specialized "pacemaker region" in the axon; (b) depolarization induced by light is the consequence of increase of membrane conductance. The major conductance changes occurring during constant illumination may be due to corresponding changes of the "stimulus" supplied by the photoreceptor or to changes of sensitivity of the eccentric cell's membrane to this stimulus. Some accessory phenomena may be the consequence of regenerative properties of the nerve cell itself.
Is the Fundamental Electrical Response of the Single Heart Muscle Cell a Spike Potential?
Authors: Churney Leon , Ohshima Hisashi
Published: May 2004

The urodele amphibians, Amphiuma and Necturus, provide heart fibers large enough to serve for microelectrode recording under visual control with the microscope. Bundles containing as few as 5 to 10 fibers yield spike potentials, rather than the plateau forms generally considered to be characteristic of heart muscle. These spikes fail to overshoot. The plateau form, and only the plateau form, is recorded exclusively from large tissue masses. An intermingling of spikes and plateau-shaped action potentials is obtained from bundles of intermediate size. These data are confirmed in experiments in which the myocardium is sliced into adhering strips of unequal sizes. The conclusion is drawn that the configuration of the recorded action potential curve is contingent upon the mass and geometry of the tissue impaled by the microelectrode. The crucial experiment of recording from an isolated single heart fiber is not possible, because of the attendant injury. Our proposal that the spike form is the elemental heart action potential is, to this extent, an extrapolation. Attempts to explain the nature of the spike along classical lines are not entirely satisfactory. Other theories are considered which, in their turn, are generally unacceptable. Evidently only further experimentation can clarify the situation.
The Effect of Ca and Antidiuretic Hormone on Na Transport across Frog Skin
Authors: Herrera Francisco C. , Curran Peter F.
Published: May 2004

Ca added to the solution bathing the outside of isolated frog skin causes a decrease in net Na transport across the skin while antidiuretic hormone (ADH) causes an increase. Possible interrelations between the effects of these agents have been examined. The decrease in Na transport caused by Ca was the same before and after treatment of the skin with ADH and the increase in transport caused by ADH was unaffected by the presence of Ca. The relationship between Ca concentration and degree of inhibition of Na transport was not appreciably altered by ADH. These results indicate that Ca and ADH do not compete but act independently at two different sites and these sites appear to be located on the same barrier to Na movement in the skin. Further, Ca causes a decrease in Cl influx across the short-circuited skin but ADH has no effect on Cl movement, again suggesting that the actions of these agents are independent.
Kinetics of Water Loss from Cells at Subzero Temperatures and the Likelihood of Intracellular Freezing
Authors: Mazur Peter
Published: May 2004

The survival of various cells subjected to low temperature exposure is higher when they are cooled slowly. This increase is consistent with the view that slow cooling decreases the probability of intracellular freezing by permitting water to leave the cell rapidly enough to keep the protoplasm at its freezing point. The present study derives a quantitative relation between the amount of water in a cell and temperature. The relation is a differential equation involving cooling rate, surface-volume ratio, membrane permeability to water, and the temperature coefficient of the permeability constant. Numerical solutions to this equation give calculated water contents which permit predictions as to the likelihood of intracellular ice formation. Both the calculated water contents and the predictions on internal freezing are consistent with the experimental observations of several investigators.