bluuebunny/crossref_metadata_2025 huggingface dataset:
The Recovery of Contractile Ability Following a Contracture in Skeletal Muscle
Authors: Curtis Brian A.
Published: May 2004

When the potassium in Ringer's solution is increased above 25 mM, frog skeletal muscle contracts and then spontaneously relaxes. Elevated external potassium will not produce tension again until the stimulating potassium has been removed and a recovery process has taken place. The kinetics of this recovery reaction have been studied in toe muscles bathed in choline Ringer's solutions in which the levels of Ca and K were varied. In 2.5 mM K the recovery reaction appears to follow first order kinetics and the recovery is slowed by lowering the external Ca. In 1.8 mM Ca the recovery is complete in 60 sec.; in 0.2 mM Ca it is 70 per cent complete. When the external K is increased to 10, 15, or 20 mM, the recovery reaches a maximum at 60 sec. and then declines. As the external K is increased, the maximum recovery achieved declines. At K concentrations above 20 mM there is no recovery. When the external Ca is reduced to 0.2 mM, the area under the contracture tension curve is reduced by 40 ± 3 per cent (mean ± SEM). When 1.6 mM Ni is added to 0.2 mM Ca Ringer's, the contracture area is restored beyond the control value. This addition of the Ni to 0.2 mM Ca Ringer's does not, however, restore the recovery reaction to its rate in 1.8 mM Ca.
The Rat Electroretinogram
Authors: Cone Richard A.
Published: May 2004

Characteristics of the electroretinogram (ERG) produced by the essentially all rod eye of the rat are presented as functions of the number of quanta absorbed by each rod per stimulus flash. The ERG's were obtained with 1.5 msec. stimulus flashes and uniform illumination of the entire retina. Under these conditions, distortions in the ERG due to stray light are minimized, and the ERG more accurately reflects the activity of its retinal sources. The effects of background light and two forms of dark adaptation were studied and compared. The results, especially for the b-wave, permit an interpretation in terms of two distinct processes. One process appears to determine the b-wave latency. This process is almost independent of the state of adaptation of the retina. The other process does not affect the latency, but determines the b-wave threshold and amplitude. This process strongly depends upon the state of adaptation. Moreover, the effects of dark adaptation on this amplitude-determining process are almost identical with the effects of background light.
Alteration of Acetylcholine Penetration into, and Effects on, Venom-Treated Squid Axons by Physostigmine and Related Compounds
Authors: Hoskin F. C. G. , Rosenberg Philip
Published: May 2004

Choline and neostigmine markedly antagonize the effect of acetylcholine (ACh) on the action potential of the venom-treated squid axon, although they themselves have no effect on conduction. Physostigmine also antagonizes the blocking action of ACh at a concentration well below that which has any effect on conduction. In contrast, d-tubocurarine (curare) increases the effect of ACh on the action potential. Choline, neostigmine, and physostigmine markedly decrease the penetration of C14-labeled ACh into the axoplasm of the squid axon. Curare, in contrast, increases the penetration of ACh, whereas dimethylcurare gives variable results. The results provide an explanation why physostigmine and neostigmine do not influence the action of ACh on axonal conduction in a way similar to that observed at the junction. The additive effect of curare and ACh on the action potential may be due either to the greater rate of penetration of ACh or to an additive effect of the two compounds on the receptor, or to a combination of both factors.
Cat Heart Muscle in Vitro
Authors: Page Ernest , Bernstein R. S.
Published: May 2004

The rate of transfer of labeled molecules across a sheet of quiescent cat right ventricle separating two chambers containing chemically identical solutions was followed at 23°C. For the diffusion of sucrose, SO4, and Na the experimental points fit the entire time course of the plot of the diffusion equation for a plane sheet. The tortuosity factor of the extracellular diffusion channel, λ was 1.44 ± 0.05 (mean ± SEM) for sucrose and similar for SO4 and Na. The fractional area available for extracellular diffusion, calculated from λ and the slope of the linear asymptote approached during steady state diffusion, was 0.17–0.23 for both impermeant species (sucrose, SO4, Na) and permeant species (water, urea, glycerol). Permeant molecules showed a characteristic prolongation of the approach to the steady state, with an unexplained "hump" in the curve for water. The observed time courses for diffusion of permeant molecules are interpreted in terms of a model proposed by Fatt et al. for diffusion through linear porous media containing dead-end pore volume. Large molecules like inulin and dialyzed dextran (diameter 150 to 180 A) diffuse through the sheet. These molecules may have a reflection coefficient σ > 0. The fraction of muscle water occupied by the sucrose diffusion channel is significantly smaller than the 3 hr. mannitol, sucrose, and inulin spaces.
The Mechanism of Isotonic Water Transport
Authors: Diamond Jared M.
Published: May 2004

The mechanism by which active solute transport causes water transport in isotonic proportions across epithelial membranes has been investigated. The principle of the experiments was to measure the osmolarity of the transported fluid when the osmolarity of the bathing solution was varied over an eightfold range by varying the NaCl concentration or by adding impermeant non-electrolytes. An in vitro preparation of rabbit gall bladder was suspended in moist oxygen without an outer bathing solution, and the pure transported fluid was collected as it dripped off the serosal surface. Under all conditions the transported fluid was found to approximate an NaCl solution isotonic to whatever bathing solution used. This finding means that the mechanism of isotonic water transport in the gall bladder is neither the double membrane effect nor co-diffusion but rather local osmosis. In other words, active NaCl transport maintains a locally high concentration of solute in some restricted space in the vicinity of the cell membrane, and water follows NaCl in response to this local osmotic gradient. An equation has been derived enabling one to calculate whether the passive water permeability of an organ is high enough to account for complete osmotic equilibration of actively transported solute. By application of this equation, water transport associated with active NaCl transport in the gall bladder cannot go through the channels for water flow under passive conditions, since these channels are grossly too impermeable. Furthermore, solute-linked water transport fails to produce the streaming potentials expected for water flow through these passive channels. Hence solute-linked water transport does not occur in the passive channels but instead involves special structures in the cell membrane, which remain to be identified.
Spontaneous Slow Potential Fluctuations in the Limulus Photoreceptor
Authors: Adolph Alan R.
Published: May 2004

Spontaneous, subthreshold fluctuations of membrane potential are recorded in the eccentric cell body or dendrite of the dark-adapted Limulus ommatidium. These slow potential fluctuations (SPF's) are random in amplitude and in time of occurrence. The relation between average frequency of SPF's and light intensity is linear for low light intensities and becomes a non-linear saturation for higher intensities. The occurrences of SPF's have Poisson statistics in the dark but are non-Poisson with light stimuli. Light-adapting the ommatidium greatly decreases the SPF amplitude, and it increases the average frequency of SPF's in the dark and in response to light (facilitatory action). The shape (time course of response) of the SPF does not change at different light intensities and it is the result of a concurrent and conterminous change in membrane resistance. The functional properties of the SPF's are analyzed in terms of a stochastic model based on the summation of random events in time ("shot effect").
Steady-State Phototropism in Phycomyces
Authors: Dennison David S.
Published: May 2004

The steady-state phototropic bending of Phycomyces sporangiophores was studied using apparatus designed to keep the growing zone vertical and the angle of illumination constant over long periods of time. The bending speed is quite constant if the intensity and angle of illumination are fixed. A phototropic inversion occurs in response to a sudden change in intensity, either an increase or a decrease. A bending component lateral to the illumination direction is strongly evident at normal incidence. It is shown that this component is due to a rotation between the stimulus and response loci about the axis of the growing zone, which is probably related to the spiral growth of the cell. The steady-state bending speed is at a maximum value for illumination directions ranging from normal incidence to about 45°. From 45 to 14° the bending speed decreases linearly with angle, reaching zero at 14°. Angles less than 14° elicit a weak negative phototropic response. Using an optical model of the growing zone, the intracellular intensity distribution was determined as a function of the angle of illumination. Several hypotheses relating the intensity distribution to the phototropic response are discussed.
An Inducible System for the Hydrolysis and Transport of ß-Glucosides in Yeast
Authors: Kaplan J. Gordin
Published: May 2004

A strain of bakers' yeast was isolated which could utilize cellobiose and other ß-D-glucosides quantitatively as carbon and energy sources for growth. Cellobiose-grown cells contained a largely cryptic enzyme active against the chromogenic substrate p-nitrophenyl-ß-D-glucoside. The patent (intact cell) activity of such cells was inhibited by azide and, competitively, by cellobiose; neither agent inhibited the ß-glucosidase activity of lysed cells or of extracts. The enzyme induced by growth in cellobiose medium had no affinity for cellobiose as either substrate or inhibitor; its substrate specificity classifies it as an aryl-ß-glucosidase. It was concluded that growth in cellobiose also induced the formation of a stereospecific and energy-dependent system whose function determined the rate at which intact cells could hydrolyze substrates of the intracellular ß-glucosidase.
Temperature and Frog Eggs
Authors: McLaren Ian A.
Published: May 2004

Bělehrádek's temperature function in which metabolic rate V is related to temperature T by
Mechanisms of Reaction of Some Flavoprotein Enzymes with Oxygen
Authors: Gibson Quentin H.
Published: May 2004

Biochemical investigations of the properties of free flavins and of flavoproteins have shown that reduction usually occurs in two stages, with the intermediate formation of semiquinones in the case of free flavins. Flavoproteins often show spectroscopically similar intermediates, when partially reduced with substrate. These may, however, be enzyme-product complexes. Detailed investigation of individual flavoprotein enzymes has shown examples in which catalysis involves transition of the enzyme between oxidized and fully reduced forms (glucose oxidase), between oxidized and intermediate forms (D-amino acid oxidase), and intermediate and fully reduced forms (TPNH—cytochrome c reductase). Further, examples are known in which both intermediate and reduced forms react with oxygen, in which only one reacts, while in TPNH—cytochrome c reductase neither the intermediate nor the reduced form reacts with molecular oxygen. The physiological significance of these complex findings is uncertain, partly because it is not known whether purified flavoproteins occur in the same form in the tissues. It seems unlikely, however, that flavoproteins make a major contribution to the respiratory exchange of mammals.
Temperature Coefficients of the Electrical Thresholds of Taste Sensations
Authors: Von Békjésy Georg
Published: May 2004

Each papilla in an enlarged photograph of the tip of the tongue was identified electrically as belonging to one of the four basic taste sensations. The temperature coefficient of the threshold for electrical stimulation was observed for single papillae. The results seem to divide the four basic taste sensations into two different groups: sour-salty and sweet-bitter. This is the same division that has been reported with other methods.
Mechanisms of Oxidation with Oxygen
Authors: Taube Henry
Published: May 2004

Several topics are dealt with in discussing the reactions of molecular oxygen, but a common goal is pursued in each: to try to understand the reactions in terms of the fundamental properties of the oxygen molecule, and of the other reactants. The paper first describes the electronic structure of oxygen and of two low-lying electronically excited states. Concern with the low-lying electronically excited states is no longer the sole property of spectroscopists; recently, evidence has been presented for the participation of such activated molecules in chemical reactions. The chemistry of oxygen is dominated by the fact that the molecule in the ground state has two unpaired electrons, whereas the products of oxidation in many important reactions have zero spin. In its reactions with transition metal ions the restrictions imposed by the spin state of the oxygen molecule are easily circumvented. A number of reactions of oxygen with metal ions have been studied in considerable detail; conclusions on basic aspects of the reaction mechanism are outlined. Among the most interesting reactions of oxygen are those in which it is reversibly absorbed by reducing agents. Reversible absorption to form a peroxide in the bound state is possible; some of the conditions which must be fulfilled by a reducing system to qualify as storing oxygen in this way are reasonably well understood and are here enunciated. Little has been done on the formation of oxygen from water; some factors involved in this process are discussed.
Electrical Properties of Neurospora crassa
Authors: Slayman Clifford L.
Published: May 2004

Glass micropipette electrodes have been employed to study the transsurface potential difference of Neurospora crassa. For mature hyphae grown in agar cultures, the internal potential is large and negative, often exceeding -200 mv. The potential is sensitive to the concentrations of extracellular potassium, sodium, hydrogen, and calcium ions, but does not vary in a manner which is readily explained by ionic diffusion potentials. With extracellular solutions containing only potassium chloride (or sulfate) and sucrose, the internal potential shifts toward zero (becomes less negative) at 45 mv per tenfold increase of potassium, over the range 0.1 to 10 mM. A similar result has been found with sodium, though the slope is only 33 mv/log unit. Calcium (1 mM) diminishes the influence of potassium and sodium by 60 to 70 per cent. As potassium or sodium is raised above 20 mM, the slope of the internal potential increases sharply to 85 to 90 mv/log unit, both in the presence and absence of calcium. With increasing hydrogen ion concentration, too, the internal potential shifts toward zero; in this case the slope is about 12 mv/pH unit at pH 9 and rises smoothly to 33 mv/pH unit at pH 3. All these phenomena are probably properties of the plasma membrane. The polysaccharide cell wall contains few fixed negative charges, has a low transverse resistance, and supports very little potential difference when separated from the plasma membrane.
The Crystal-Solution Problem of Sperm Whale Myoglobin
Authors: Urnes Peter
Published: May 2004

The central question to be discussed in this paper is whether the structure established for sperm whale myoglobin in the crystalline state is the same as that of the protein in solution. As judged by its ultraviolet optical rotatory dispersion, the helical content of metmyoglobin in solution does not differ from that in the crystal, 77 per cent. Although an uncertainty of about ±5 per cent must attach to this result, it excludes many alternative arrangements of the polypeptide chain. The folding of the chain may be further restricted to the basic form seen in the crystal if the dimensions of the molecule in solution and the interactions of specific chemical groups are taken into account. Since the rotatory dispersion of metmyoglobin is constant with respect to ionic strength, and since the dispersions of reduced and oxymyoglobin reveal no change in helical content upon their formation from metmyoglobin, one may infer that the structure of the protein is largely maintained both as it dissolves and during its reversible combination with oxygen. The crystallographic model of myoglobin thus offers a structural basis for attempting to explain its physiological function in solution. The relevance of this conclusion to the crystal-solution problems presented by other species of protein is then best seen in the light of common factors that govern the equilibrium of all proteins between crystal and solution.
Electrical Properties of Neurospora crassa
Authors: Slayman Clifford L.
Published: May 2004

The internal potential of Neurospora appears to have two components, one (a) which is reduced by anoxia or abolished by respiratory inhibitors such as azide and 2,4-dinitrophenol, and (b) a fraction that remains in the presence of respiratory inhibitors and is sensitive to the external potassium concentration. Under standard conditions 1 mM azide or dinitrophenol diminishes internal potentials from near -200 mv to about -30 mv within 1 minute and at a maximal rate of 20 mv/second. The internal potential usually recovers within 10 minutes after the inhibitor has been removed. The effect of carbon monoxide on the internal potential is similar to that of azide or dinitrophenol, but can be reversed by visible light, specifically of the wavelengths (430 mµ and 590 mµ) known to decompose cytochrome-CO complexes in yeast. Respiration and internal potentials vary proportionally with azide concentration, but dinitrophenol at low (3 x 10-6 M) concentrations enhances oxygen consumption without affecting the internal potential. In the presence of 0.1 mM calcium, the fraction of the internal potential which persists during respiratory inhibition increases (becomes more negative) about 30 mv for each tenfold decrease of external potassium over the range 10 to 0.1 mM. The surface resistivity of Neurospora, normally about 5000 ohm.cm2, is unchanged by respiratory inhibitors during the period of rapid potential shift.
Do Flies Have A Red Receptor?
Authors: Goldsmith Timothy H.
Published: May 2004

(1) The compound eye of Musca exhibits characteristics which have heretofore frequently been considered evidence for color receptors: (a) The spectral sensitivity curve has several peaks whose relative heights can be altered by selective adaptation to colored lights, and (b) the shape of the retinal action potential varies with wave length. (2) The action spectrum for the red enhancement of on and off responses is compared with the "red receptor" calculated by Mazokhin-Porshnyakov from colorimetric data obtained in rapid color substitutions. Both have maxima at 615 to 620 mµ and appear to be different expressions of the same phenomenon. (3) A red receptor is absent. The evidence which suggests different types of receptors in the region 500 to 700 mµ can be accounted for by variations in the numbers of receptors stimulated. In red light there is a recruitment of additional ommatidia caused by leakage of long wave lengths through the pigment screen, and this spatial summation potentiates the on and off responses. The principal evidence is: (a) a white eye mutant which has no accessory screening pigments also lacks the peak of sensitivity in the red, even when adapted to violet light; (b) white-eyed flies give identical responses with large on and off effects at all wave lengths from 500 to 700 mµ; and (c) reducing the number of excited ommatidia by decreasing the size of the test spot makes the on and off transients smaller relative to the receptor component.
Effect of Insulin on Potassium Flux and Water and Electrolyte Content of Muscles from Normal and from Hypophysectomized Rats
Authors: Zierler Kenneth L. , Rogus Ellen , Hazlewood Carlton F.
Published: May 2004

It was reported previously that insulin hyperpolarized rat skeletal muscle and decreased K+ flux in both directions. The observations on K+ flux are now extended to take advantage of the greater sensitivity to insulin of hyperphysectomized rats. Insulin caused a shift of water from extracellular to intracellular space if glucose was present, but not in its absence. Insulin caused net gain of muscle fiber K+, though not necessarily an increase in K+ concentration in fiber water. It probably also decreased intrafiber Na+ and Cl-. Insulin decreased K+ efflux. The effect was dose-dependent. Muscles from hypophysectomized rats were more sensitive to the action of insulin on K+ flux than were those from normal rats. The effect was demonstrable within the time resolution of the system, suggesting that insulin's action is on cell surfaces. K+ influx was also decreased by insulin. Bookkeeping suggests that some K+ influx be called active. Insulin seemed to decrease active K+ influx and passive K+ efflux. It is not resolved whether insulin has a true dual effect or whether it acts only on passive fluxes in both directions (the apparent action on active K+ influx being an artefact of incomplete definition of passive flux) or whether a single alteration in the membrane may affect both active and passive fluxes.
Effects of the Intracellular Ca Ion Concentration upon the Excitability of the Muscle Fiber Membrane of a Barnacle
Authors: Hagiwara Susumu , Nakajima Shigehiro
Published: May 2004

The membrane excitability and contraction were examined in single barnacle muscle fibers with different internal Ca++ concentrations by using buffer solutions made up with EGTA and Ca-gluconate in various proportions. During the passage of dc currents the membrane shows all-or-none spike potentials for internal Ca++ concentrations below about 8 x 10-8 M, oscillatory potential changes in the range between 8 x 10-8 to 5 x 10-7 M, but neither oscillatory nor spike potentials were seen for concentrations above 5 x 10-7 M. All-or-none spike potentials were suppressed when the internal Mg++ concentration exceeded 5 mM. The suppression threshold of the internal Ca++ concentration for the Sr spike is much higher than that for the Ca spike. The threshold concentration of internal Ca++ for contraction was about 8 x 10-7 M.
Polysaccharide Biosynthesis
Authors: Robbins P. W. , Wright A. , Dankert M.
Published: May 2004

Polysaccharide synthesis is discussed from the point of view of the sources of biological information that determine the structures and control the rates of synthesis of complex polysaccharides. It is concluded that three types of information contribute in important and different ways, namely enzyme specificity, primer substances, and the structure of the cytoplasmic membrane. Each of these factors is discussed in a general way with examples of its contribution to the structure and organization of specific polysaccharides.
THE VISIBILITY OF MONOCHROMATIC RADIATION AND THE ABSORPTION SPECTRUM OF VISUAL PURPLE
Authors: Hecht Selig , Williams Robert E.
Published: May 2004

1. After a consideration of the existing data and of the sources of error involved, an arrangement of apparatus, free from these errors, is described for measuring the relative energy necessary in different portions of the spectrum in order to produce a colorless sensation in the eye.

2. Following certain reasoning, it is shown that the reciprocal of this relative energy at any wave-length is proportional to the absorption coefficient of a sensitive substance in the eye. The absorption spectrum of this substance is then mapped out.

3. The curve representing the visibility of the spectrum at very low intensities has exactly the same shape as that for the visibility at high intensities involving color vision. The only difference between them is their position in the spectrum, that at high intensities being 48 µµ farther toward the red.

4. The possibility is considered that the sensitive substances responsible for the two visibility curves are identical, and reasons are developed for the failure to demonstrate optically the presence of a colored substance in the cones. The shift of the high intensity visibility curve toward the red is explained in terms of Kundt's rule for the progressive shift of the absorption maximum of a substance in solvents of increasing refractive index and density.

5. Assuming Kundt's rule, it is deduced that the absorption spectrum of visual purple as measured directly in water solution should not coincide with its position in the rods, because of the greater density and refractive index of the rods. It is then shown that, measured by the position of the visibility curve at low intensities, this shift toward the red actually occurs, and is about 7 or 8 µµ in extent. Examination of the older data consistently confirms this difference of position between the curves representing visibility at low intensities and those representing the absorption spectrum of visual purple in water solution.

6. It is therefore held as a possible hypothesis, capable of direct, experimental verification, that the same substance—visual purple—whose absorption maximum in water solution is at 503 µµ, is dissolved in the rods where its absorption maximum is at 511 µµ, and in the cones where its maximum is at 554 µµ (or at 540 µµ, if macular absorption is taken into account, as indeed it must be).
THE INFLUENCE OF ELECTROLYTES ON THE CATAPHORETIC CHARGE OF COLLOIDAL PARTICLES AND THE STABILITY OF THEIR SUSPENSIONS
Authors: Loeb Jacques
Published: May 2004

1. When collodion particles suspended in water move in an electric field they are, as a rule, negatively charged. The maximal cataphoretic P.D. between collodion particles and water is about 70 millivolts. This is only slightly more than the cataphoretic P.D. found by McTaggart to exist between gas bubbles and water (55 millivolts). Since in the latter case the P.D. is entirely due to forces inherent in the water itself, resulting possibly in an excess of OH ions in the layer of water in contact and moving with the gas bubble, it is assumed that the negative charge of the collodion particles is also chiefly due to the same cause; the collodion particles being apparently only responsible for the slight difference in maximal P.D. of water-gas and water-collodion surfaces.

2. The cataphoretic charge of collodion particles seems to be a minimum in pure water, increasing as a rule with the addition of electrolytes, especially if the cation of the electrolyte is monovalent, until a maximal P.D. is reached. A further increase in the concentration of the electrolyte depresses the P.D. again. There is little difference in the action of HCl, NaOH, and NaCl or LiCl or KCl.

3. The increase in P.D. between collodion particles and water upon the addition of electrolyte is the more rapid the higher the valency of the anion. This suggests that this increase of negative charge of the collodion particle is due to the anions of the electrolyte gathering in excess in the layer of water nearest to the collodion particles, while the adjoining aqueous layer has an excess of cations.

4. In the case of chlorides and at a pH of about 5.0 the maximal P.D. between collodion particles and water is about 70 millivolts, when the cation of the electrolyte present is monovalent (H, Li, Na, K); when the cation of the electrolyte is bivalent (Mg, Ca), the maximal P.D. is about 35 to 40 millivolts; and when the cation is trivalent (La) the maximal P.D. is lower, probably little more than 20 millivolts.

5. A reversal in the sign of charge of the collodion particles could be brought about by LaCl3 but not by acid.

6. These results on the influence of electrolytes on the cataphoretic P.D. between collodion particles and water are also of significance for the theory of electrical endosmose and anomalous osmosis through collodion membranes; since the cataphoretic P.D. is probably identical with the P.D. between water and collodion inside the pores of a collodion membrane through which the water diffuses.

7. The cataphoretic P.D. between collodion particles and water determines the stability of suspensions of collodion particles in water, since rapid precipitation occurs when this P.D. falls below a critical value of about 16 millivolts, regardless of the nature of the electrolyte by which the P.D. is depressed. No peptization effect of plurivalent anions was noticed.
THE COLLOIDAL BEHAVIOR OF SERUM GLOBULIN
Authors: Hitchcock David I.
Published: May 2004

1. The globulin prepared from ox serum by dilution and precipitation with carbon dioxide has been found, by electrometric titration experiments, to behave like an amphoteric electrolyte, reacting stoichiometrically with acids and bases.

2. The potential difference developed between a solution of globulin chloride, phosphate, or acetate and a solution of the corresponding acid, free from protein, separated from the globulin by a collodion membrane, was found to be influenced by hydrogen ion concentration and salt concentration in the way predicted by Donnan's theory of membrane equilibrium. In experiments with sodium globulinate and sodium hydroxide it was found that the potential difference could be similarly explained.

3. The osmotic pressure of such solutions could be qualitatively accounted for by the Donnan theory, but exhibited a discrepancy which is explicable by analogy with certain experiments of Loeb on gelatin.

4. The application of Loeb's theory of colloidal behavior, which had previously been found to hold in the case of gelatin, casein, egg albumin, and edestin, has thus been extended to another protein, serum globulin.
THE EXCRETION OF CARBON DIOXIDE BY RELAXED AND CONTRACTED SEA ANEMONES
Authors: Parker G. H.
Published: May 2004

1. The metabolism of the sea anemone Metridium marginatum Edw. was measured in four states, relaxed, relaxing, contracted, and contracting, by means of an Osterhout respiratory apparatus. The basis of measurement was the number of hundred-thousandths of a milligram of carbon dioxide excreted per second by a gram of living sea anemone.

2. In the relaxed state this varied from 6.1 to 4.4+ and averaged 5.43–.

3. In a comparison of the relaxed and contracted states the amount of carbon dioxide excreted was found to beabout the same; in one instance in relaxation 4.2 and in contraction 4.1+; in another in relaxation 7.8+ and 7.9– and in contraction 8.1–.

4. In a comparison of the three states relaxed, relaxing, and contracting, the first two were found to average about the same, 4.8+ and 4.6– respectively and the last proved to be appreciably higher 7.1–.

5. It is, therefore, concluded that the process of relaxing and the states of relaxation and of contraction are accompanied by no unusual metabolism, but that in the operation of contracting the metabolism becomes about half again as intense as that characteristic of the other states.

6. The maintenance of the contracted state in Metridium for days at a time without an increase of metabolism indicates that its musculature is of the type known as tonus muscle.

7. In tonus muscle, contraction is accomplished by an active shortening of the myofibrils, extension by a passive drawing out of these fibrils through the distension of the adjacent cavities, etc., and the continued maintenance of any particular state of shortening by some form of catch mechanism in the muscle, such, possibly, as the gelation of its sarcoplasm.
ABSORPTION OF NUTRIENTS AND PLANT GROWTH IN RELATION TO HYDROGEN ION CONCENTRATION
Authors: Arrhenius Olof
Published: May 2004

The absorption of nutrients depends to a large extent on the reaction of the substrate. At maximal growth the intake of salt is at minimum. Different ions are very differently affected. The intake of water is independent of the absorption of salts.
THE STABILITY OF BACTERIAL SUSPENSIONS
Authors: De Kruif Paul H. , Northrop John H.
Published: May 2004

1. The amount of immune body required to agglutinate a suspension of Bacillus typhosus increases in direct proportion to the concentration of the suspension.

2. The amount of immune body combined with the organisms is constant from pH 9 to pH 3.7. Below the latter value the amount in combination is decreased.

3. The addition of immune serum to a suspension of Bacillus typhosus at a pH of 2,5 increases the positive charge of the organisms.

These results are contradictory to the idea that the combination is caused by a difference in the sign of the charge carried by the immune body and the organism. They agree with the assumption that the immune body forms a film on the surface of the organism and that the effect on the charge is the result of this film.
THE ADHESIVENESS OF LEUCOCYTES TO SOLID SURFACES
Authors: Fenn Wallace O.
Published: May 2004

1. Methods are described for measuring the stickiness of cells to solid surfaces.

2. The effect of various factors such as temperature, serum concentration, sodium chloride concentration, etc., on the adhesiveness of leucocytes to solid surfaces and the phagocytosis of solid particles are compared, and certain marked differences pointed out.

3. On account of these differences it is concluded that forces of surface tension, though undoubtedly operative in determining the behavior of cells in contact with solid bodies, are not the only factors involved.

4. Ways in which changes in the structure or rigidity of the protoplasm might affect phagocytosis and adhesiveness in opposite directions are suggested.
EFFECT OF THE HYDROGEN ION CONCENTRATION ON THE PHAGOCYTOSIS AND ADHESIVENESS OF LEUCOCYTES
Authors: Fenn Wallace O.
Published: May 2004

1. Immediately after coming into contact with glass, leucocytes are most adhesive at pH 8.0 or > 8.0.

2. Agglutination of leucocytes increases with increasing H ion concentration from pH 8.0 to 6.0.

3. In phagocytosis experiments where leucocytes creep about on the slide picking up articles the optimum pH is 7.0. Here ameboid movement is probably the limiting factor.

4. The optimum for phagocytosis of quartz from suspension is on the acid side of neutrality at or near pH 6.7.

5. Phagocytosis of quartz increases with the acidity, while adhesiveness of leucocytes to glass increases with the alkalinity.
THE INFLUENCE OF AMMONIUM SALTS ON CELL REACTION
Authors: Jacobs M. H.
Published: May 2004

1. It may be shown by means of cells of the flowers of a hybrid Rhododendron which contain a natural indicator, by means of starfish eggs stained with neutral red, and by means of an "artificial cell" in which living frog's skin is employed that increased intracellular alkalinity may be brought about by solutions of a decidedly acid reaction which contain ammonium salts.

2. These results are analogous to those previously obtained with the CO2-bicarbonate system, and depend on the facts: (a) that NH4OH is sufficiently weak as a base to permit a certain degree of hydrolysis of its salts; and (b) that living cells are freely permeable to NH4OH (or NH3?) and not to mineral and many organic acids, and presumably not at least to the same extent to ammonium salts as such.
A MICRO INJECTION STUDY ON THE PERMEABILITY OF THE STARFISH EGG
Authors: Chambers Robert
Published: May 2004

The experiments with the NH4Cl are similar to, and corroborate micro injection experiments performed in connection with some work on mustard gas in which the writer collaborated. Eggs immersed in sea water containing decomposed mustard gas, at a certain low concentration are not affected. If, however, the solution be injected, the egg quickly cytolyzes owing to the free HCl present.

A similar impermeability of the protoplasmic surface film to certain substances was also encountered in injection work on Amœba. Amœbœ immersed in an aqueous solution of eosin will not take the stain till after death. On the other hand, the eosin, when injected into the Amœba, quickly permeates the protoplasm, to be arrested only at the surface.

The semipermeability of a living cell appears primarily to be a function of its surface film. It is immaterial whether this film be that of the original cortex of the cell, a film newly formed over a cut surface, or a film that surrounds an artificially induced vacuole within the cell. As long as such a surface film exists neither the acid group of the NH4Cl nor the alkaline group of the NaHCO3 can, within certain concentration limits, penetrate the protoplasm. These solutions, if injected beneath the surface film, however, will produce their characteristic effects upon the protoplasm.
THE PERMEABILITY OF LIVING CELLS TO DYES AS AFFECTED BY HYDROGEN ION CONCENTRATION
Authors: Irwin Marian
Published: May 2004

1. An accurate quantitative method of measuring the penetration of dye into the living cell is described.

2. Cresyl blue is unable to penetrate rapidly unless the pH outside the cell is decidedly greater than that inside. The rate of penetration increases with increasing pH.

3. Around pH 9 penetration of the dye is rapid while the reverse is true of exosmosis. At low pH values (5.9) exosmosis is rapid and penetration is very slow.
THE MECHANISM OF THE INFLUENCE OF ACIDS AND ALKALIES ON THE DIGESTION OF PROTEINS BY PEPSIN OR TRYPSIN
Authors: Northrop John H.
Published: May 2004

1. The effect of the addition of acid on the amount of ionized protein has been compared with the effect on the rate of digestion of gelatin, casein, and hemoglobin by pepsin.

2. A similar comparison has been made of the addition of alkali in the case of trypsin with gelatin, casein, hemoglobin, globin, and edestin.

3. In general, the rate of digestion may be predicted from the amount of ionized protein as determined by the titration curve or conductivity. The rate of digestion is a minimum at the isoelectric point of the protein and a maximum at that pH at which the protein is completely combined with acid or alkali to form a salt.

4. The physical properties of the protein solution have little or no effect on the rate of digestion.
STUDIES ON BIOLUMINESCENCE
Authors: Harvey E. Newton
Published: May 2004

Oxyluciferin may be reduced to luciferin at cathodes, when an electric current is passed through the solution, or at cathodes formed by metal couples in solution, or at cathodes of oxidation-reduction cells of the NaCl - Pt - Pt - Na2S type. It is also reduced at those metal surfaces (Al, Mn, Zn, and Cd) which liberate nascent hydrogen from water, although no visible hydrogen gas separates from the surface. Molecular hydrogen does not reduce oxyluciferin even though very finely divided but will reduce oxyluciferin in contact with palladium. Palladium has no reducing action except in presence of hydrogen, and apparently acts as a catalyst by virtue of some power of converting molecular into atomic hydrogen. Conditions are described under which a continuous luminescence of luciferin can be obtained. This luminescence may be used as a test for atomic hydrogen. It is suggested that the steady luminescence of bacteria is due to continuous oxidation of luciferin to oxyluciferin and reduction of oxyluciferin to luciferin in different parts of the bacterial cell.
MUSCLE TENSION AND REFLEXES IN THE EARTHWORM
Authors: Moore A. R.
Published: May 2004

1. By the use of preparations of earthworm in which the cutaneous receptors have been anesthetized with a solution of M/8 MgCl2, it is shown that peristalsis can be initiated by tension alone.

2. The receptors of the tension reflex are the intermyal sensory cells of the ventral region of the body wall.

3. It is concluded that Straub obtained the tension reflex because his preparations contained the intermyal receptors; Budington was unable to observe the tension reflex in any preparation from which the intermyal receptors had been removed.

4. Intermyal receptors are the receptors of the following reaction: Passive unilateral tension of the posterior part of an earthworm induces active homolateral tension of the musculature of the anterior segments, and results in the course of progress being brought into line with the enforced orientation of the tail. This reaction is termed the homostrophic reflex.

5. The receptors for the reaction are distributed throughout the entire length of the worm, the effectors are limited to the anterior 15 to 20 segments. The impulse is conducted by the ventral nerve cord.

6. The interaction of the homostrophic reflex and tropisms is considered.
FURTHER OBSERVATIONS ON THE INFLUENCE OF SALTS WHEN INJECTED INTO THE ANIMAL BODY
Authors: Hussey Raymond G.
Published: May 2004

A satisfactory correlation of our observations dealing with the influence of salts and those dealing with the influence of x-rays is not possible at present. Any far reaching conclusion is not permitted because the information we have at this time regarding the physical chemical conditions concerned in the process of injury, as well as that pertaining to the nature of radio-chemical reactions, is too meager. As far as the experiments with salts are concerned, it may be said that we are dealing with ion effects, and their importance in physiological processes is made clear by the investigations of Loeb (3) and those of Osterhout (4). The results that we have obtained in our experiments present an interesting analogy between the effect of x-rays and certain salts on the lymphoid elements of the animal body. We regard this analogy as significant in that it presents suggestions regarding the chemical nature of x-ray effects in the animal body.
CONDUCTIVITY AS A MEASURE OF VITALITY AND DEATH
Authors: Brooks S. C.
Published: May 2004

The conductance of Laminaria, Saccharomyces, Bacillus coli and Bacillus butyricus, Chlorella, and of red blood cells has been studied by the writer's method, and Laminaria by that of Osterhout. For the material studied it has been found that:

1. The conductance of living tissue is closely proportionate to, and determined by that of the surrounding fluid with which it is apparently in equilibrium. Changes in the conductance of the fluid are quickly followed by compensatory changes in that of the tissue.

2. A quantity is defined which is independent of the conductivity of the fluid bathing the tissues. This is called the "net conductance."

3. All the tissues studied, even when dead, offer a resistance to the passage of current greater than that of the surrounding solution. Exceptions which occur under certain conditions will be discussed in a later paper.

4. In view of the wide variety of material studied it seems admissible, in the absence of any evidence to the contrary, to suppose that these conclusions are generally applicable.
THE BEHAVIOR OF CHLORIDES IN THE CELL SAP OF NITELLA
Authors: Irwin Marian
Published: May 2004

1. A method is given for determining the chloride content in a drop (less than 0.03 cc.) of the cell sap of Nitella.

2. Chlorides accumulate in the sap to the extent of 0.128 M; this accumulation can be followed during the growth of the cell. The chloride content does not increase when the cell is placed for 2 days in solutions (at pH 6.2) containing chlorides up to 0.128 M.

3. The exosmosis of chlorides from injured cells can be followed quantitatively. When one end of the cell is cut off a wave of injury progresses toward the other end; this is accompanied by a progressive exosmosis of chlorides.
THE RATE OF DECLINE OF MILK SECRETION WITH THE ADVANCE OF THE PERIOD OF LACTATION
Authors: Brody Samuel , Ragsdale Arthur C. , Turner Charles W.
Published: May 2004

It is shown that the course of decline of milk secretion with the advance of the period of lactation may be expressed by the equation of a monomolecular chemical reaction; that is, the percentage decline of milk secretion with the advance of the stage of lactation is constant. This substantiates the idea that milk secretion is limited by a chemical reaction, and, in general, brings lactation into the class of processes the speed of which is determined by the concentration of a limiting substance.
THE REACTION OF NEREIS VIRENS TO UNILATERAL TENSION OF ITS MUSCULATURE
Authors: Moore A. R.
Published: May 2004

1. The anterior segments of Nereis are oriented reflexly by passive unilateral tension of the posterior musculature.

2. The afferent impulses of the homostrophic reflex rise from any part of the worm and are conducted forward by way of the ventral nerve cord.

3. The efferent impulses flow out from the brain and anterior two or three ventral ganglia.

4. The homostrophic reflex may be partially or wholly masked by stereotropism.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Ray George B.
Published: May 2004

1. Chloroform in low concentration (0.25 per cent) causes an increase in the rate of production of CO2 in Ulva; this is followed by a decrease. In higher concentration (0.5 per cent) only a decrease is observed.

2. Assuming that the normal oxidation depends on the action of peroxide and peroxidase, experiments were made by placing Ulva in 1.0 per cent H2O2 and in Fe2(SO4)3 (which acts like a peroxidase). The former diminishes the rate, the latter increases and subsequently decreases it.

3. When Ulva is killed in such a manner as to destroy the oxidizing enzymes, no CO2 is produced unless H2O2 and Fe2(SO4)3 are present. If to this mixture chloroform is added, the effect depends on the concentration of the iron. If the concentration is low there is an increase in the production of CO2 followed by a decrease. If the concentration is high the rate appears to decrease from the start.
HOMOSTROPHIC REFLEX AND STEREOTROPISM IN DIPLOPODS
Authors: Crozier W. J. , Moore A. R.
Published: May 2004

1. With suitable arthropods, such as the diplopods, it can be shown that body orientation following passive unilateral tension involves the homostrophic reflex. The phenomenon is exhibited when the animal is quiescent and during forward locomotion, but nothing of the sort appears in backward locomotion.

2. Receptors for the homostrophic reflex are in the body wall and are distributed throughout the length of the animal.

3. The effector nerves take their origin from the ganglia of the head alone.

4. The diplopods are stereotropic, the head turning toward the side in contact with a solid surface only as long as some part of the body maintains contact. Under suitable conditions stereotropism may mask the homostrophic reflex.

5. When a diplopod is in contact with two lateral surfaces of equal extent the path upon emergence is a straight one, conforming to the law of the parallelogram of forces.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Ray George B.
Published: May 2004

1. Organic acids when treated with H2O2 and Fe2(SO4)3 produce CO2 at a rate that can be measured by the indicator method.

2. In the case of acids containing a double bond, the rate of production of CO2 can be varied by the addition of an anesthetic. The changes in the rate of production of CO2 under the influence of a typical anesthetic, such as chloroform, show a striking resemblance to the reaction of the organism.