bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE RELATIONSHIP BETWEEN SODIUM, POTASSIUM, AND CHLORIDE IN AMPHIBIAN MUSCLE
Authors: Simon Shirley E. , Shaw F. H. , Bennett Susanne , Muller Margaret 
Published: May 2004

The Na,+ Cl-, and K+ content of toad plasma and the sartorius muscle has been determined. Although the Na+ and Cl- level of the muscles in the living animal varied greatly (0 to 38.0 m.eq. per kg., and 0 to 31.8 m.eq. per kg. respectively) the K+ level was subject to a smaller variation (76.5 to 136 m.eq. per kg.). There was a direct relationship between Na+ and Cl-, which was independent of the K+ level.
There is a closely related gain of Na+ and Cl- when muscle is soaked in normal Ringer. These gains are not related to the K+ loss, frequently found on soaking.
The relationship between the three ions was studied in a large series of 124 muscles in normal Ringer. As found in vivo, there was a correlation between Na+ and Cl.- This correlation was independent of K+ content, except when this was abnormally low.
Alteration of the external NaCl level produced concomitant changes in the internal levels of these ions.
Alteration of the external KCl level produced an increase in internal Cl- similar to that found with high NaCl solutions, but the amount of K+ entering the cell was approximately one-third of the external increase.
Removal of K+ from the external solution did not result in a loss of K+ from the cell, although there was an adequate amount of Cl- present to accompany it.
The results cannot be reconciled with either a Donnan concept for the accumulation of K+, or a linked carrier system.
A theory is proposed to account for the ionic differentiation within the cell. The K+ is assumed to be adsorbed onto an ordered intracellular phase. The normal metabolic functioning of the cell is necessary to maintain the specificity of the adsorption sites. There is another intracellular phase, which lacks the structural specificity for K+, and which contains Na+, Cl-, and K+ in equilibrium with the external solution. The dimensions of the free intracellular phase will vary from cell to cell, but it will be smaller in the intact animal, and will increase on soaking in normal Ringer, until it is approximately one-third of the total cellular volume. The increase in this phase may be ascribed to a decrease in the energy available to maintain the ordered phase.
ON THE MEASUREMENT OF CARBON DIOXIDE UPTAKE WITH A GLASS ELECTRODE
Authors: Rosenberg Jerome L. 
Published: May 2004

1. It has been shown that the glass electrode method as previously described by the author for measurements of transient rates in photosynthesis is free of systematic errors.
2. Justification has been given for the use of the steady state-gas flow method for measuring rates of assimilation under conditions in which the solution is known not to be seriously depleted of CO2.
3. The decline of photosynthetic rates under light saturation at CO2 pressures less than several tenths per cent of an atmosphere has been shown to be a real phenomenon. It has been suggested that there may be a real discrepancy between this finding and those of some other investigators due to a difference in the previous history of the algal suspensions.
DEMONSTRATION OF TWO STABLE POTENTIAL STATES IN THE SQUID GIANT AXON UNDER TETRAETHYLAMMONIUM CHLORIDE
Authors: Tasaki Ichiji , Hagiwara Susumu 
Published: May 2004

1. Intracellular injection of tetraethylammonium chloride (TEA) into a giant axon of the squid prolongs the duration of the action potential without changing the resting potential (Fig. 3). The prolongation is sometimes 100-fold or more.
2. The action potential of a giant axon treated with TEA has an initial peak followed by a plateau (Fig. 3). The membrane resistance during the plateau is practically normal (Fig. 4). Near the end of the action potential, there is an apparent increase in the membrane resistance (Fig. 5D and Fig. 6, right).
3. The phenomenon of abolition of action potentials was demonstrated in the squid giant axon treated with TEA (Fig. 7). Following an action potential abolished in its early phase, there is no refractoriness (Fig. 8).
4. By the method of voltage clamp, the voltage-current relation was investigated on normal squid axons as well as on axons treated with TEA (Figs. 9 and 10).
5. The presence of stable states of the membrane was demonstrated by clamping the membrane potential with two voltage steps (Fig. 11). Experimental evidence was presented showing that, in an "unstable" state, the membrane conductance is not uniquely determined by the membrane potential.
6. The effect of low sodium water was investigated in the axon treated with TEA (Fig. 12).
7. The similarity between the action potential of a squid axon under TEA and that of the vertebrate cardiac muscle was stressed. The experimental results were interpreted as supporting the view that there are two stable states in the membrane. Initiation and abolition of an action potential were explained as transitions between the two states.
THE METAMORPHOSIS OF VISUAL SYSTEMS IN THE SEA LAMPREY
Authors: Wald George 
Published: May 2004

The life cycle of the sea lamprey, Petromyzon marinus, includes two metamorphoses. At the end of a period spent as a blind larva, buried in the mud of streams, a first metamorphosis prepares it to migrate downstream to the sea or a lake for its growth phase. Then, following a second metamorphosis, it migrates upstream as a sexually mature adult to spawn and die.
The downstream migrants have a visual system based upon rhodopsin and vitamin A1, whereas that of the upstream migrants is based upon porphyropsin and vitamin A2. The livers contain vitamin A1 at all stages.
The sea lamprey therefore exhibits a metamorphosis of visual systems, like those observed earlier among amphibia. The presence of porphyropsin in this member of the most primitive living group of vertebrates, as in fishes and amphibia, supports the notion that porphyropsin may have been the primitive vertebrate visual pigment. Its association with fresh water existence throughout this range of organisms also is consistent with the view that the vertebrate stock originated in fresh water. The observation that in the life cycle of the lamprey rhodopsin precedes porphyropsin is not at variance with the idea that porphyropsin is the more primitive pigment, since this change is part of the second metamorphosis, marking the return to the original environment. The observation that in lampreys, fishes, and amphibia, porphyropsin maintains the same general association with fresh water, and rhodopsin with marine and terrestrial habit, suggests that a single genetic mechanism may govern this association throughout this wide span of organisms.
LYSIS FROM WITHOUT OF S. AUREUS K1 BY THE COMBINED ACTION OF PHAGE AND VIROLYSIN
Authors: Ralston Doris J. , Baer Beatrice S. , Lieberman Miriam , Krueger Albert P. 
Published: May 2004

Lysis from without (LFW) occurs in two steps: (1) sensitization of cells by phage, which renders the cells susceptible to (2) destruction of an essential cell structure by an extracellular lytic enzyme. Virolysin, from phage-infected cells, was used in these studies. Normal cell autolysin is also effective.
Evidence is presented that:
1. Neither phage nor lysin alone causes LFW.
2. Sensitization requires phage adsorption.
3. It can be caused by non-infectious particles. This establishes a new biological activity of the particle.
4. Heat, U.V., detergents, penicillin, and other damaging agents also sensitize cells.
5. Sensitization involves a non-lethal, reversible reaction.
6. Sensitization by phage prevents virus synthesis. Following adsorption, a cell can undergo sensitization or infection but not simultaneously. When only a few particles are adsorbed, infection can occur; when sufficient particles are adsorbed, sensitization takes place.
7. Quantitative aspects of LFW are described. Lysis proceeds logarithmically. The lysis end-point depends upon the phage concentration but is independent of the enzyme concentration.
PHOTOREACTIVATION IN VITRO OF ULTRAVIOLET INACTIVATED HEMOPHILUS INFLUENZAE TRANSFORMING FACTOR
Authors: Rupert Claud S. , Goodgal Sol H. , Herriott Roger M. 
Published: May 2004

Hemophilus influenzae—transforming DNA, which has been inactivated by ultra-violet radiation, is reactivated by visible light in the presence of a cell-free extract of Escherichia coli B.
The time rate of reactivation is increased by increasing the E. coli extract concentration, the temperature, and the intensity of illumination.
Only DNA containing an ultraviolet-damaged genetic marker exhibits increased transforming activity after treatment with the photoreactivating system.
The reactivating capacity of the extract remains in the top supernatant after centrifugation at 110,000 x g for 1 hour and is not present in the pellet. This capacity is destroyed by heating to 90°C. for 1 minute.
The active system of the E. coli extract is separable into dialyzable, heat-stable and non-dialyzable, heat-labile fractions. The dialyzable fraction contains at least one component which limits the maximum degree of recovery attained.
THE RHODOPSIN SYSTEM OF THE SQUID
Authors: Hubbard Ruth , St. George Robert C. C. 
Published: May 2004

Squid rhodopsin (λmax 493 mµ)—like vertebrate rhodopsins—contains a retinene chromophore linked to a protein, opsin. Light transforms rhodopsin to lumi- and metarhodopsin. However, whereas vertebrate metarhodopsin at physiological temperatures decomposes into retinene and opsin, squid metarhodopsin is stable.
Light also converts squid metarhodopsin to rhodopsin. Rhodopsin is therefore regenerated from metarhodopsin in the light. Irradiation of rhodopsin or metarhodopsin produces a steady state by promoting the reactions,
See PDF for Equation
Squid rhodopsin contains neo-b (11-cis) retinene; metarhodopsin all-trans retinene. The interconversion of rhodopsin and metarhodopsin involves only the stereoisomerization of their chromophores.
Squid metarhodopsin is a pH indicator, red (λmax 500 mµ) near neutrality, yellow (λmax 380 mµ) in alkaline solution. The two forms—acid and alkaline metarhodopsin—are interconverted according to the equation,
Alkaline metarhodopsin + H+ ⇌acid metarhodopsin,
with pK 7.7. In both forms, retinene is attached to opsin at the same site as in rhodopsin. However, metarhodopsin decomposes more readily than rhodopsin into retinene and opsin.
The opsins apparently fit the shape of the neo-b chromophore. When light isomerizes the chromophore to the all-trans configuration, squid opsin accepts the all-trans chromophore, while vertebrate opsins do not and hence release all-trans retinene.
Light triggers vision by affecting directly the shape of the retinene chromophore. This changes its relationship with opsin, so initiating a train of chemical reactions.
THE POSTSPIKE POSITIVITY OF UNMEDULLATED FIBERS OF DORSAL ROOT ORIGIN
Authors: Gasser Herbert S. 
Published: May 2004

The positivity following the spike in the action potential of unmedullated nerve fibers of dorsal root origin (d.r.C) has been shown to be homologous with the first positive potential (P1) of other varieties of nerve fibers. Thus it is only through the large size of the positivity that this group of nerve fibers is set apart from other groups. New findings accentuate and make more explicit the difference of d.r.C fiber behavior from that of the sympathetic unmedullated fibers.
Support of the conclusion is derived from re-examination of the A fibers as well as from observations on the d.r.C fibers.
Increase in size of the P1's in a tetanus of the d.r.C fibers can occur if the frequency is high enough; and it does not occur in an A fiber tetanus if the frequency is low enough. Frequency is also critical in the obtainment of increasing P1's in a tetanus of sympathetic C fibers.
Decrease in the size of the P1's in the course of a tetanus is attributable to development of the negative after-potential (N a-p). In rested d.r.C fibers the N a-p is latent. But it appears during a tetanus, develops in size, and after the tetanus leads to a long lasting and clearly defined second positive potential.
Absence of a supernormal period during the N a-p of the d.r.C fibers is accounted for.
An analysis is made of the apparent increase in size of the spike elevations during a tetanus, for the two subgroups of the C fibers.
The difference between the after-potentials of A fibers and of sympathetic C fibers is correlated with the shapes of the curves of cathodal electrotonus of these fibers.
ACTIVE SODIUM TRANSPORT BY THE ISOLATED TOAD BLADDER
Authors: Leaf Alexander , Anderson John , Page Lot B. 
Published: May 2004

Studies were made of the active ion transport by the isolated urinary bladder of the European toad, Bufo bufo, and the large American toad, Bufo marinus. The urinary bladder of the toad is a thin membrane consisting of a single layer of mucosal cells supported on a small amount of connective tissue.
The bladder exhibits a characteristic transmembrane potential with the serosal surface electrically positive to the mucosal surface. Active sodium transport was demonstrated by the isolated bladder under both aerobic and anaerobic conditions. Aerobically the mean net sodium flux across the bladder wall measured with radioactive isotopes, Na24 and Na22, just equalled the simultaneous short-circuit current in 42 periods each of 1 hour's duration. The electrical phenomenon exhibited by the isolated membrane was thus quantitatively accounted for solely by active transport of sodium. Anaerobically the mean net sodium flux was found to be slightly less than the short-circuit current in 21 periods of observation. The cause of this discrepancy is not known.
The short-circuit current of the isolated toad bladder was regularly stimulated with pure oxytocin and vasopressin when applied to the serosal surface under aerobic and anaerobic conditions. Adrenaline failed to stimulate the short-circuit current of the toad bladder.
THE PROLONGED GROWTH AND SURVIVAL OF OVARIAN TISSUE OF THE PROMETHEA MOTH (CALLOSAMIA PROMETHEA) IN VITRO
Authors: Grace T. D. C. 
Published: May 2004

1. The ovarian tissues from diapausing pupae of the promethea moth (Callosamia promethea) have survived and grown for 186 days under in vitro conditions. There was continual cell migration and multiplication for a period of 53 days, followed by a period of 47 days during which no cells migrated from the tissues. Between the 100th and 105th days after setting up the cultures, cell migration was resumed, and by the 111th day 250 cells were present in the medium. A few cell divisions were observed between the 126th and 136th days. After the tissues were subcultured on the 140th day, the explant culture continued to survive, but the cell culture died 3 days later.
2. The tissues were subcultured a total of 6 times during the 186 days. By the introduction of a piece of live tissue into the cell cultures, the growth and survival of the cells were increased from 8 days to about 20 days.
3. It is possible that the tissues had become adapted to the medium during their long survival, as the cells which migrated from them after 100 days showed considerably longer survival than those in earlier cultures.
THE EFFECTIVENESS OF THE LONGITUDINAL FIELD, COUPLED WITH DEPOLARIZATION IN ACTIVATING FROG TWITCH MUSCLES
Authors: Csapo Arpad , Suzuki Taizo 
Published: May 2004

Effective excitation, preceding the mechanical response in frog twitch muscles, involves two distinct events: depolarization of the excitable membrane and the flow of internal currents. To distinguish between the effects of these two potential factors in activation of the contractile machinery, experiments ought to be conducted in which one or the other is excluded. Our experiments are designed to distinguish between these effects by indirect methods.
Depolarization in a longitudinal electric field can be expected to be greatest at the ends where current leaves the muscle fibers (space constant at [K] = 16 mM/liter is &gt;1 mm.), whereas the internal longitudinal current is known to be greatest in the middle portion. Depolarization, therefore, should affect the ends more strongly and internal current the middle portion.
Our experiments show that non-propagating frog twitch muscles shorten, during isotonic work, along their whole length and not only at their ends, when effectively stimulated in a longitudinal A.C. field. At a field strength about twice the new threshold value (at [K]o = 16 mM) shortening is distinctly greater in the middle portion of the muscle than at the ends. The muscles, although temporarily non-propagating, remain intact throughout the experiment, as demonstrated by complete recovery after repolarization.
These findings may be taken as an indication that internal currents are more directly linked to activation than is depolarization, but the latter is an essential priming step, which must precede or coincide with effective current flow.
THE EFFECT OF ENZYME INHIBITORS ON THE RESTING POTENTIAL AND ON THE ION DISTRIBUTION OF THE SARTORIUS MUSCLE OF THE FROG
Authors: Van der Kloot William G. 
Published: May 2004

Isolated frog sartorii were exposed for 30 minutes to HETP—an irreversible anti-cholinesterase, and were then soaked in Ringer's at 15°C. for 16 hours. At the end of the period of soaking the mean resting potential of the muscle fibers was only 29 mv.
The decrease in the resting potential of the HETP-treated muscles was accompanied by a loss of potassium and a gain in sodium by the muscles.
The effect of anticholinesterases on sodium extrusion was studied by incubating the muscles in a Ringer's containing half of the normal amount of sodium. The muscles respond by extruding sodium against a concentration gradient into the external medium. Sodium extrusion was blocked by prior exposure of the muscle to HETP, and reversibly blocked by exposure to physostigmine. The inhibition of sodium extrusion by physostigmine was correlated with the inhibition of the intracellular cholinesterase.
Sodium extrusion was also blocked by high concentrations of 2-methyl-1,4-napthaquinone 8-sulfonic acid and by α-ketoglutarate, which are known to inhibit choline acetylase in vitro. But sodium extrusion was not affected by a third inhibitor of choline acetylase, phenobarbital.
Sodium extrusion was unaffected by KCN and partially blocked by IAA. The IAA block was eliminated by the addition of pyruvate. It is concluded that either glycolysis or oxidative metabolism can furnish the energy needed for sodium extrusion.
SODIUM EXCLUSION AND POTASSIUM RETENTION BY THE RED MARINE ALGA, PORPHYRA PERFORATA
Authors: Eppley Richard W. 
Published: May 2004

Cells of the red marine alga, Porphyra perforata, accumulate potassium and exclude sodium, chloride, and calcium. Various metabolic inhibitors including dinitrophenol, anoxia, and p-chloromercuribenzoate partially abolish the cells' ability to retain potassium and exclude sodium. Iodoacetate induces potassium loss only in the dark; reduced sulfur compounds offer protection against the effects of p-chloromercuribenzoate; dinitrophenol stimulates respiration at concentrations which cause potassium loss and sodium gain.
Following exposure to anoxia potassium accumulation and sodium extrusion take place against concentration gradients. These movements are retarded by sodium cyanide, but are stimulated by light.
Sodium entry, following long exposure to 0.6 M sucrose, occurs rapidly with the concentration gradient, while potassium entry against the concentration gradient takes place slowly, and is prevented by cyanide.
THE TOPOGRAPHY OF TIP GROWTH IN A PLANT CELL
Authors: Castle Edward S. 
Published: May 2004

Tips of young Phycomyces sporangiophores were dusted with starch grains, and growth photographically recorded. Rates of longitudinal displacement from the cell tip of individual markers were determined, also corresponding rates of change of cell diameter. From these the magnitude and spatial distribution of "relative elemental growth rates" along both longitudinal and circumferential axes of the cell were obtained.
Growth rates in these two directions are functions of distance from the cell apex, and have different spatial distributions. In particular, rates of growth in cell circumference are complexly patterned. Relative elemental growth rates in length and in girth are approximately equal and maximal at the cell's apex, with a value of 2.4 mm. mm.–1 hr.–1. The characteristic shape of the tip is maintained constant in the face of its changing substance and position. This shape reflects a steady state of the cell's constituent growth patterns.
At every point the growing membrane simultaneously expands in the two dimensions of its surface. The degree of polarization or directional preference of growth is measured by the ratio of longitudinal to circumferential relative elemental growth rate at any point. The ratio is not constant, but changes with position along the tip. This fact does not support the idea that membrane growth is based upon a quantal "growth event." Possible causal factors in oriented membrane growth are discussed.
PROLONGED ACTION POTENTIALS FROM SINGLE NODES OF RANVIER
Authors: Mueller Paul 
Published: May 2004

The duration of action potentials from single nodes of Ranvier can be increased by several methods. Extraction of water from the node (e.g. by 2 to 3 M glycerin) causes increased durations up to 1000 msec. 1 to 5 min. after application of the glycerin the duration of the action potential again decreases to the normal value.
Another type of prolonged action potential can be observed in solutions which contain K or Rb ions at concentrations between 50 mM and 2 M. The nodes respond only if the resting potential is restored by anodal current.
The kinetics of these action potentials is slightly different. Their maximal durations are longer (up to 10 sec.). Like the normal action potential, they are initiated by cathodal make or anodal break. They also occur in external solutions which contain no sodium.
The same type of action potentials as in KCl is found when the node is depolarized for some time (15 to 90 sec., 100 to 200 mv.) and is then stimulated by cathodal current. These action potentials require no K or Na ions in the external medium. Their maximal duration increases with the strength and duration of the preceding depolarization. The possible origin of the action potentials in KCl and after depolarization, and their relation to the normal action potentials and the negative after-potential are discussed.
THE RATE OF UPTAKE OF CARBON MONOXIDE AND OF NITRIC OXIDE BY NORMAL HUMAN ERYTHROCYTES AND EXPERIMENTALLY PRODUCED SPHEROCYTES
Authors: Carlsen Elizabeth , Comroe Julius H. 
Published: May 2004

The uptake of gases such as oxygen, carbon monoxide, or nitric oxide by the erythrocyte involves: (a) diffusion across the cellular membrane, (b) intraerythrocytic diffusion, and (c) chemical combination with hemoglobin. The aim of this investigation was to obtain data which would permit an analysis of each of these factors in limiting the rate of gas uptake.
The initial over-all rate of uptake of gases which combine chemically with hemoglobin to produce a color change can be measured by a modified version of the Hartridge-Roughton-Millikan constant flow, rapid reaction apparatus. If nitric oxide is the reactant gas, only (a) and (b) are measured since the chemical combination of this gas with hemoglobin is extremely rapid. Our studies have shown that human biconcave discoidal erythrocytes at 38 and 48°C., have the same initial rate of carbon monoxide and nitric oxide uptake as the same cells converted into spherocytes of equal volume. Similarly there was no difference between discs and cells sphered with a 30 per cent increase in volume. Shrunken erythrocytes showed a marked decrease in rate of gas uptake. This suggests that surface area and maximum linear distance for intracellular diffusion of this magnitude do not measurably retard gas uptake. In the shrunken cells, a change in the orientation and concentration of intraerythrocytic hemoglobin and/or of the membrane components may have impeded gas diffusion.