bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EXCITABILITY OF FROG MUSCLE WITH PARTICULAR REFERENCE TO ITS LATENT ADDITION
Authors: Blair H. A.
Published: May 2004

With a view to indicating that the α excitatory state in muscle is not of a special nature it is shown that the α strength-duration curves are of the same form as those determined for nerve and other tissues except that in about two-thirds of all cases the rheobase appears to be slightly too low. Also from experiments in latent addition it is found that the α excitatory state following an inadequate stimulus subsides exponentially at a rate which is related to the α excitability in the same way, approximately, as the subsidence rate in nerve is related to the nerve's excitability. In both tissues the subsidence as measured directly is 2–3 times as fast as it appears to be from the strength-duration curve. The α refractory period is at least as short as that of nerve so the α chronaxie is unusually long compared to the refractory period. There is no reason at present, however, to consider this as having any bearing on the problem at issue. It is concluded therefore, that the α excitability differs from others in the rates of its reactions rather than in its fundamental nature and that any conclusions about excitability drawn from its study will probably be valid quite generally.
ELECTRIC IMPEDANCE OF FERTILIZED ARBACIA EGG SUSPENSIONS
Authors: Cole Kenneth S. , Spencer Joseph M.
Published: May 2004

From the low frequency alternating current impedance and the volume concentrations of suspensions of Arbacia eggs, it is shown that the high resistance membrane is either at or very near the plasma membrane for both unfertilized and fertilized eggs, and that the specific resistances of the perivitelline space and fertilization membrane are not greatly different from that of sea water. The effect of the capacity element which appears after fertilization at intermediate frequencies is considerably less than in the earlier experiments on Arbacia and Hipponoë eggs.

These findings indicate that the fertilization membrane does not have the high capacity previously attributed to it and that the increase in membrane capacity takes place at or near the plasma membrane.
STUDIES IN THE PHYSICAL CHEMISTRY OF AMINO ACIDS, PEPTIDES, AND RELATED SUBSTANCES
Authors: Cohn Edwin J. , McMeekin Thomas L. , Blanchard Muriel H.
Published: May 2004

1. As an introduction to the relations that obtain in biochemical systems containing several components, some ionic, some dipolar ionic, the solubility of cystine has been investigated in the presence of glycine and neutral salts.

2. Both glycine and sodium chloride increase cystine solubility at all concentrations. The interaction between cystine and ions is, however, diminished with increase in glycine concentration, and the interaction between cystine and glycine with increase in ionic strength.

3. Sodium sulfate also increases the solubility of cystine, but at concentrations greater than one molal its solvent action is smaller than its salting-out effect, which is greater at all concentrations than that of sodium chloride, and greater the higher the glycine concentration.

4. These interactions are defined by an equation giving the solubility ratio of cystine in terms of salting-out constants, constants related to the electric moments of cystine, and to the ionic strength and dielectric constant of the solution.

5. The higher the concentration of glycine and therefore the dielectric constant of the solution, the smaller that part of the interaction between ions and dipolar ions which depends upon Coulomb forces and the greater appears the salting-out effect.

6. Conversely, the greater the ionic strength and the salting-out effect the smaller the interaction between dipolar ions in solution.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G. , Osterhout W. J. V.
Published: May 2004

Analyses of the sap of Halicystis Osterhoutii and of Valonia macrophysa for iodide indicate accumulations of the order of 1000 to 10,000-fold in the first case, and 40 to 250-fold in the second case. The chemical potential of KI, NaI, HI, and CaI2 is greater inside than outside.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G.
Published: May 2004

When cells of Valonia macrophysa were placed in hypertonic sea water, the concentration of halide and of nitrate increased, and the sum of halide + nitrate became 0.05 M greater inside than outside, which is about the same difference as is found in cells in normal sea water.

In ordinary sea water the ratio of halide to nitrate is 80,000 to 1. When this was changed by substituting nitrate for halide so that the concentration of halide was 1.75 times that of nitrate the rate of entrance of halide was 1.68 times that of nitrate in 276 hours and the ratio of halide to nitrate in the sap decreased from 38 to 18.5.

No halide came out in exchange for entering nitrate. The retention of chloride may well be due to the fact that even when the halide concentration of the sea water is reduced as low as 0.4 M, there is still an inwardly directed activity gradient of sodium chloride.
THE EFFECT OF HYDROGEN ION CONCENTRATION UPON THE INDUCTION OF POLARITY IN FUCUS EGGS
Authors: Whitaker D. M.
Published: May 2004

1. Gradients of hydrogen ion concentration across Fucus eggs growing in sea water determine the developmental polarity of the embryo.

2. Gradients may determine polarity even if removed before the morphological response begins.

3. The rhizoid forms on the acid side of the egg unless this is too acid, in which case it develops on the basic side of the egg.

4. Since gradients of hydrogen ion concentration in sea water produce gradients of CO2 tension, as a result of chemical action on the carbonate buffer system, it is not proven whether the physiological effects are due to the hydrogen ions, or to the CO2 which they produce in the medium.

5. The developmental response of the eggs to gradients of hydrogen ion (or CO2) concentration provides an adequate but not an exclusive explanation of the group effect in Fucus.

6. Hydrogen ions may exert their effect by activating growth substance. Hydrogen ions or CO2 probably also affect the underlying rhizoid forming processes in other ways as well.
THE ELECTROPHORETIC MOBILITY OF HUMAN ERYTHROCYTES—WHOLE CELLS, GHOSTS, AND FRAGMENTS
Authors: Byler W. H. , Rozendaal H. M.
Published: May 2004

The electrophoretic mobility of human red cell ghosts decreases in the presence of chicken serum. The decrease is not directly due to the presence of adsorbed material but to a change which is catalyzed by the foreign substance. It is suggested that abnormal serum materials resulting from disease may serve as catalysts.

Fragments of broken cells have the same mobility as whole cells at first, then decrease even in pure salt suspension, while the whole cells remain essentially unchanged for hours.

The results suggest that the slow change of whole cells, the change of ghosts in the presence of foreign serum, and the change of fragments are all manifestations of the same modification of structure or composition of the cell surface.
DELAYED POTASSIUM EFFECT IN NITELLA
Authors: Hill S. E. , Osterhout W. J. V.
Published: May 2004

In normal cells of Nitella replacement of NaCl by KCl makes the P.D. much less positive: this is called the potassium effect.

Cells which have lost the potassium effect usually show little or no change of P.D. when NaCl is replaced by KCl but an occasional cell responds after a delay.

It seems possible that the delay may be largely due to the time required for potassium to combine with an organic substance, thus forming a compound which sensitizes the protoplasmic surface to the action of potassium.
ELECTRIC IMPEDANCE OF NITELLA DURING ACTIVITY
Authors: Cole Kenneth S. , Curtis Howard J.
Published: May 2004

The changes in the alternating current impedance which occur during activity of cells of the fresh water plant Nitella have been measured with the current flow normal to the cell axis, at eight frequencies from 0.05 to 20 kilocycles per second, and with simultaneous records of the action potential under the impedance electrodes. At each frequency the resting cell was balanced in a Wheatstone bridge with a cathode ray oscillograph, and after electrical stimulation at one end of the cell, the changes in the complex impedance were determined from the bridge unbalance recorded by motion pictures of the oscillograph figure. An extension of the previous technique of interpretation of the transverse impedance shows that the normal membrane capacity of 0.9 µf./cm.2 decreases about 15 per cent without change of phase angle, while the membrane resistance decreases from 105 ohm cm.2 to about 500 ohm cm.2 during the passage of the excitation wave. This membrane change occurs during the latter part of the rising phase of the action potential, and it is shown that the membrane electromotive force remains unchanged until nearly the same time. The part of the action potential preceding these membrane changes is probably a passive fall of potential ahead of a partial short circuit.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Hill S. E. , Osterhout W. J. V.
Published: May 2004

Treatment of Nitella with NaCl greatly reduces the time required for the action current and produces an action curve with one peak instead of the customary two. The time may be reduced to 0.6 second in place of the usual 15 to 30 seconds.

This might be expected if the treatment increased the conductivity of the aqueous part of the protoplasm. The experiments favor this idea although they do not prove its correctness.

This effect is prevented by calcium, possibly because calcium inhibits penetration of salts. That penetration is an important factor is indicated by the fact that salts which might be expected to penetrate rapidly have the most effect. Thus NaSCN is more effective than NaCl but Na2SO4 has little or no effect. The action of NH4Cl and LiCl is similar to that of NaCl.
CHEMICAL CHANGES IN THE ADDUCTOR MUSCLE OF THE CHELIPED OF THE CRAYFISH IN RELATION TO THE DOUBLE MOTOR INNERVATION
Authors: Bergren W. R. , Wiersma C. A. G.
Published: May 2004

An investigation has been made of the phosphate and lactic acid changes in the adductor muscle of the cheliped of the crayfish Cambarus clarkii upon stimulation of the isolated axons for the fast and slow contractions at determined frequencies. The data obtained point to the following conclusions:

1. When the mechanical effects of the two types of contraction are the same, the chemical changes are of the same order. If the mechanical effects are different, the chemical changes likewise are not equivalent. This is especially to be seen in the case of stimulation at 50 shocks per second: a slowly rising, long continued, strong slow contraction takes place with no apparent change in the phosphate content; a quickly rising fast contraction occurs with a large increase in the phosphate.

2. Since equivalent chemical changes accompany equivalent mechanical action, the two types of contraction do not differ in the essential mechanism of the chemical changes involved, and only one type of contractile substance is present.

3. Even when a contraction has taken place to the maximum extent obtainable, only enough phosphate is found to correspond to one-fifth to one-third of the available phosphagen.
FORMATION OF NEW CRYSTALLINE ENZYMES FROM CHYMOTRYPSIN
Authors: Kunitz M.
Published: May 2004

A solution of chymotrypsin on slight hydrolysis undergoes an irreversible change into new proteins, two of which are enzymes and have been isolated in crystalline form. The new crystalline enzymes, called beta and gamma chymotrypsins, differ from the original chymotrypsin as well as from each other in many physical and chemical respects, such as molecular weight, crystalline form, solubility, and combining capacity with acid. The new enzymes still possess the same enzymatic properties as chymotrypsin. It thus appears that the irreversible change from chymotrypsin to the new enzymes does not affect the structure responsible for the enzymatic activity of the molecule.

The solubility curves of the new enzymes agree approximately with the curves for a solid phase of one component and furnish very good evidence that the preparations represent distinct substances. The various enzymes when mixed at the proper pH have a tendency to form mixed crystals of the solid solution type. Thus at pH 4.0 gamma chymotrypsin combines to form solid solution crystals with either alpha or beta chymotrypsin. Hence at this pH separation of gamma from either alpha or beta by means of fractional crystallization is impossible. At pH 5.0–6.0, however, each material crystallizes in its own characteristic form and at its own rate; thus a fractional separation of the various enzymes from each other becomes feasible.
EFFECT OF THE FORMATION OF INERT PROTEIN ON THE KINETICS OF THE AUTOCATALYTIC FORMATION OF TRYPSIN FROM TRYPSINOGEN
Authors: Kunitz M.
Published: May 2004

A solution of crystalline trypsinogen in dilute buffer containing a trace of active trypsin when allowed to stand at pH 5.0–9.0 and 5°C. is gradually transformed partly into trypsin protein and partly into an inert protein which can no longer be changed into trypsin either by enterokinase or mold kinase.

During the process of formation of trypsin and inert protein the ratio of the concentrations of the two products in any reaction mixture remains constant and is independent of the original concentration of trypsinogen protein. This ratio varies, however, with the pH of the solution, the proportion of trypsin formed being greater in the acid range of pH.

The experimental curves for the rate of formation of trypsin, as well as for the rate of formation of inert protein are symmetrical S shaped curves closely resembling those of simple autocatalytic reactions.

The kinetics of formation of trypsin and inert protein can be explained quantitatively on the theoretical assumptions that both reactions are of the simple unimolecular type, that in each case the reaction is catalyzed by trypsin, and that the rate of formation of each of the products is proportional to the concentration of trypsin as well as to the concentration of trypsinogen in solution.
THE GROWTH OF BACTERIOPHAGE
Authors: Ellis Emory L. , Delbrück Max
Published: May 2004

1. An anti-Escherichia coli phage has been isolated and its behavior studied.

2. A plaque counting method for this phage is described, and shown to give a number of plaques which is proportional to the phage concentration. The number of plaques is shown to be independent of agar concentration, temperature of plate incubation, and concentration of the suspension of plating bacteria.

3. The efficiency of plating, i.e. the probability of plaque formation by a phage particle, depends somewhat on the culture of bacteria used for plating, and averages around 0.4.

4. Methods are described to avoid the inactivation of phage by substances in the fresh lysates.

5. The growth of phage can be divided into three periods: adsorption of the phage on the bacterium, growth upon or within the bacterium (latent period), and the release of the phage (burst).

6. The rate of adsorption of phage was found to be proportional to the concentration of phage and to the concentration of bacteria. The rate constant ka is 1.2 x 10–9 cm.8/min. at 15°C. and 1.9 x 10–9 cm.8/min. at 25°.

7. The average latent period varies with the temperature in the same way as the division period of the bacteria.

8. The latent period before a burst of individual infected bacteria varies under constant conditions between a minimal value and about twice this value.

9. The average latent period and the average burst size are neither increased nor decreased by a fourfold infection of the bacteria with phage.

10. The average burst size is independent of the temperature, and is about 60 phage particles per bacterium.

11. The individual bursts vary in size from a few particles to about 200. The same variability is found when the early bursts are measured separately, and when all the bursts are measured at a late time.
CHANGES OF APPARENT IONIC MOBILITIES IN PROTOPLASM
Authors: Osterhout W. J. V.
Published: May 2004

In Nitella, as in Halicystis, guaiacol increases the mobility of Na+ in the outer protoplasmic surface but leaves the mobility of K+ unaffected. This differs from the situation in Valonia where the mobility of Na+ is increased and that of K+ is decreased.

The partition coefficient of Na+ in the outer protoplasmic surface is increased and that of K+ left unchanged.

Recovery after the action current is delayed in the presence of guaiacol and the action curves are "square topped."
FORMATION OF TRYPSIN FROM CRYSTALLINE TRYPSINOGEN BY MEANS OF ENTEROKINASE
Authors: Kunitz M.
Published: May 2004

Crystalline trypsinogen is most readily and completely transformed into trypsin by means of enterokinase in the range of pH 5.2–6.0 at 5°C. and at a concentration of trypsinogen of not more than 0.1 mg. per ml. The action of enterokinase under these conditions is that of a typical enzyme. The process follows closely the course of a catalytic unimolecular reaction, the rate of formation of trypsin being proportional to the concentration of enterokinase added and the ultimate amount of trypsin formed being independent of the concentration of enterokinase.

The catalytic action of enterokinase on crystalline trypsinogen in dilute solution at pH more alkaline than 6.0 and in concentrated solution at pH even slightly below 6.0 is complicated by the partial transformation of the trypsinogen into inert protein which can no longer be changed into trypsin even by a large excess of enterokinase. This secondary reaction is catalyzed by the trypsin formed and the rate of the reaction is proportional to the concentration of trypsin as well as to the concentration of trypsinogen in solution. Hence under these conditions only a small part of the trypsinogen is changed by enterokinase into trypsin while a considerable part of the trypsinogen is transformed into inert protein, the more so the lower the concentration of enterokinase used.

The kinetics of the formation of trypsin by means of enterokinase when accompanied by the formation of inert protein can be explained quantitatively on the theoretical assumption that both reactions are of the simple catalytic unimolecular type, the catalyst being enterokinase in the first reaction and trypsin in the second reaction.
THE FLICKER RESPONSE CONTOUR FOR THE ISOPOD ASELLUS
Authors: Crozier W. J. , Wolf Ernst , Zerrahn-Wolf Gertrud
Published: May 2004

The flicker response contour for the isopod Asellus is a simple probability integral (F - log I) over the whole determinable range (F = 1 to 51). This contrasts with the "distorted" asymmetrical curves obtained with Apis, Anax, and other arthropods with large convex eyes. The explanation of the distortion as due to mechanical conditions affecting photoreception is therefore confirmed, as the structure of the Asellus eye does not make such a factor likely to be expected for this case.

The Asellus curve agrees with the only other available complete and uncomplicated flicker response contour (from Pseudemys, turtle with rod-free retina), in showing the superiority of the probability integral formulation as compared with certain others which have been suggested.

It is noted as a curious and probably important fact that the relative dispersion of the intensity thresholds (σ'log I) for the elements implicated in determining the flicker contour appears to be identical in bee, dragon fly nymph, and isopod. Other relevant information derived from similar experiments with vertebrates shows that this quantity is specifically determined by the organization of the animal. The nature of the common feature of neural organization in three such diverse arthropods, as contrasted with the diversity seen within one class of vertebrates (e.g., teleosts), remains to be discovered.
MEMBRANE AND PROTOPLASM RESISTANCE IN THE SQUID GIANT AXON
Authors: Cole Kenneth S. , Hodgkin Alan L.
Published: May 2004

The direct current longitudinal resistance of the squid giant axon was measured as a function of the electrode separation. Large sea water electrodes were used and the inter-electrode length was immersed in oil. The slope of the resistance vs. separation curve is large for a small electrode separation, but becomes smaller and finally constant as the separation is increased.

An analysis of the resistance vs. length curves gives the following results. The nerve membrane has a resistance of about 1000 ohm cm.2 The protoplasm has a specific resistance of about 1.4 times that of sea water. The resistance of the connective tissue sheath outside the fiber corresponds to a layer of sea water about 20µ in thickness. The characteristic length for the axon is about 2.3 mm. in oil and 6.0 mm. in sea water.
THE EFFECTS OF ULTRAVIOLET RADIATION ON SPORES OF THE FUNGUS ASPERGILLUS NIGER
Authors: Zahl Paul A. , Koller L. R. , Haskins C. P.
Published: May 2004

The survival ratio of Aspergillus spores exposed to ultraviolet radiation has been measured as a function of total incident energy for wave lengths of 2537 Å, 3022 Å, 3129 Å, and 3650 Å.

The effect of humidity on killing of Aspergillus spores by ultraviolet radiation has been found to be negligible.

A delay in germination as a result of irradiation has been found.

The Bunsen-Roscoe reciprocity law has been found to hold within the limits of the radiation intensities studied.

Certain morphological changes have been observed.
TEMPERATURE AND CRITICAL ILLUMINATION FOR REACTION TO FLICKERING LIGHT
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

At fixed flash frequency (F = 20, F = 55) and with constant light time fraction (50 per cent) in the flash cycle, the critical illumination I for response of Anax nymphs to visual flicker falls continuously as the temperature rises. The temperature characteristic µ for the measure of excitability (1/I) increases continuously with elevation of temperature. The form of the F - log I curve does not change except at quite high temperature (35.8°), and then only slightly (near F = 55); Fmax. is not altered. The very unusual form of the 1/I curve as a function of temperature is quantitatively accounted for if two processes, with respectively µ = 19,200 and µ = 3,400, contribute independently and simultaneously to the control of the speed of the reaction governing the excitability; the velocities of these two processes are equal at 15.9°.
THE FLICKER RESPONSE CONTOUR FOR THE CRAYFISH. I
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

The F - log I curve for threshold response to visual flicker has been determined for the crayfish Cambarus bartoni. As predicted on the basis of the higher curvature of the optic surface, the flicker response contour is more asymmetrical than for bee and dragonfly nymph under comparable conditions of temperature and light time fraction of flash cycle. The mechanical origin of this asymmetry is thus confirmed, and is further supported by the similar forms of the F - log I curves in bee, dragonfly larva, and crayfish in the lower portion of the curves (up to F = 70 per cent Fmax.). The slope of the fundamental curve for crayfish, deduced by analysis of the data, is lower than for bee, dragonfly nymph, or Asellus. This signifies a wider spread of the effective distribution of elemental log I thresholds involvable in the response to flicker, and may be traced either to the greater curvature of the eye-surfaces or to their position upon movable pedicles. The results are therefore consistent with the statistical conception of the nature of effects recognizable as due to the activity of excitable elements.
THE KINETICS OF PENETRATION
Authors: Jacques A. G.
Published: May 2004

The rate of entrance of electrolyte and of water into impaled cells of Halicystis Osterhoutii is unaffected by raising the pH of the sea water to 9.2 or lowering it to 7.0. It is quite possible that sodium enters by combining with an organic acid HX produced by the protoplasm. If the pK' of this acid is sufficiently low the change in external pH would not produce much effect on the rate of entrance of sodium.

The rate of entrance of electrolytes is affected by light. In normal light (i.e. natural succession of daylight and darkness) the rate is about twice as great as in darkness.
STUDIES CONCERNING THE NATURE OF THE SECRETORY ACTIVITY OF THE ISOLATED RINGER-PERFUSED FROG LIVER
Authors: Hober Rudolf
Published: May 2004

The isolated Ringer-perfused frog liver is able to concentrate in its secretion several hundred or even thousand times a great number of dyestuffs. When two dyestuffs are perfused simultaneously, the liver separates them to a lower or higher degree, some times to such an extent that the secretion of one of them is entirely suppressed by the other. Which one of the two dyestuffs appears prevailingly in the secretion, does not depend upon its diffusibility or lipoid solubility, but perhaps upon its adsorbability. This is concluded from the fact that dyestuffs provided with several (4 to 5) strongly hydrophilic sulfonate groups in their molecule, are not permitted to pass the gland.
ON THE RELATION BETWEEN BIRTH WEIGHT AND LITTER SIZE, IN MICE
Authors: Crozier W. J.
Published: May 2004

For mice, as for various other mammals, the relation between number N of young in a litter and the weight W of the litter can be expressed as W = aNK. For adequately homogeneous data K has the nonspecific value 0.83. With data not homogeneous with respect to certain conditions the equation may still be descriptive, but with K higher than 0.83.

Two kinds of mice obeying this formulation, with the same K, are an albino strain (AA) and a flex-tail foetal anemic (aa). Their ideal weights of a litter of 1 (W1, free from effects of intrauterine competition) are quite different. Their F1 offspring (from AA mothers) give W1 precisely intermediate.

To test the partition theory for the basis of the parabolic equation, backcross and F2 litters were obtained in which for a span of litter sizes there occurred various proportions of anemic to non-anemic young. For equal numbers of each in the same litters the relation of weight of aa to weight of Aa young is again described by Wa = aWAK, and as before K = 0.83.

Examination of the weights of anemic and of non-anemic young, for various proportions of the two in litters of different total numbers, shows that the partition theory can account for a number of the curious relations, including the fact that aa young and Aa young if in mixed litters increase in weight more for an increment of 1 in the litter than if in unmixed litters of the same N. This mechanical result of partitioning can be regarded as a kind of model for heterosis resulting from developmental disharmony.
THE REACTIONS OF IODINE AND IODOACETAMIDE WITH NATIVE EGG ALBUMIN
Authors: Anson M. L.
Published: May 2004

The following experimental results have been obtained.

1. Native egg albumin treated with iodine and then denatured no longer gives a nitroprusside test or reduces dilute ferricyanide in neutral Duponol PC solution.

2. More iodine is needed to abolish the ferricyanide reduction if the reaction between native egg albumin and iodine is carried out at pH 6.8 than if the reaction is carried out at pH 3.2. At pH 6.8 iodine reacts with tyrosine as well as with cysteine.

3. Cysteine and tryptophane are the only amino acids with reducing groups which are known to react with dilute iodine at pH 3.2 The reducing power of cysteine is abolished by the reaction with iodine, whereas the reducing power of tryptophane remains intact. Pepsin and chymotrypsinogen which contain tryptophane but not cysteine, do not react at all with dilute iodine at pH 3.2.

4. Native egg albumin treated with iodoacetamide at pH 9.0 and then denatured by Duponol PC reduces only 60 per cent as much dilute ferricyanide as egg albumin which has not been treated with iodoacetamide.

5. The SH group is the only protein reducing group which is known to react with iodoacetamide.

The simplest explanation of the new observation that the SH groups of egg albumin can be modified by reactions with the native form of the protein is that the native egg albumin has free and accessible but relatively unreactive SH groups which can react with iodine and iodoacetamide despite the fact that they do not react with ferricyanide, porphyrindin, or nitroprusside.

Preliminary experiments suggested by the results with egg albumin indicate that the tobacco mosaic virus is modified by iodine at pH 2.8 without being inactivated and that the tobacco mosaic and rabbit papilloma viruses are not inactivated by iodoacetamide at pH 8.0.
STUDIES ON CELL METABOLISM AND CELL DIVISION
Authors: Clowes G. H. A. , Krahl M. E.
Published: May 2004

1. The effects of a number of respiratory inhibiting agents on the cell division of fertilized eggs of Arbacia punctulata have been determined. For eggs initially exposed to the reagents at 30 minutes after fertilization at 20°C., the levels of oxygen consumption prevailing in the minimum concentrations of reagents which produced complete cleavage block were (as percentages of the control): In 0.4 per cent O2-99.6 per cent N2, 32; in 0.7 per cent O2-99.3 per cent CO, 32; in 1.6 x 10–4M potassium cyanide, 34; in 1 x 10–3M phenylurethane, 70; in 4 x 10–3M 5-isoamyl-5-ethyl barbituric acid, 20; in 3 x 10–4M iodoacetic acid, 53.

2. The carbon monoxide inhibition of oxygen consumption and cell division was reversed by light. The percentage inhibition of oxygen consumption by carbon monoxide in the dark is described by the usual mass action equation with K, the inhibition constant, equal to approximately 60, as compared to values of 5 to 10 for yeast and muscle. In 20 per cent O2-80 per cent CO in the dark there was a slight stimulation of oxygen consumption, averaging 20 per cent.

3. Spectroscopic examination of fertilized and unfertilized Arbacia eggs reduced by hydrosulfite revealed no cytochrome bands. The thickness and density of the egg suspension was such as to indicate that, if cytochrome is present at all, the amount in Arbacia eggs is extremely small as compared to that in other tissues having a comparable rate of oxygen consumption.

4. Three reagents poisoning copper catalyses, potassium dithio-oxalate (10–2M), diphenylthiocarbazone (10–4M), and isonitrosoacetophenone (2 x 10–3M) produced no inhibition of division of fertilized Arbacia eggs.

5. These results indicate that the respiratory processes required to support division in the Arbacia egg may perhaps differ in certain essential steps from the principal respiratory processes in yeast and muscle.
THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA
Authors: French C. S.
Published: May 2004

1. Photosynthetic bacteria in water suspension break open when treated with supersonic vibration thus liberating the cell contents, including a water soluble protein to which is attached the otherwise water insoluble pigments, bacteriochlorophyll and carotinoids. Both types of pigments appear to be combined with the same protein.

2. The protein pigment compound is insoluble in the region of pH 3.0 to 4.5 and in neutral solution can be completely precipitated by 0.5 saturated (NH4)2SO4. It is soluble in distilled water and adsorbable on fullers' earth.

3. Supersonic extracts of photosynthetic bacteria do not have the ability to carry on photosynthesis, but will act as a photocatalyst for the oxidation of ascorbic acid with visible or infrared radiation. The rate of the photochemical oxidation is proportional to the light intensity.
THE CELL SAP OF HYDRODICTYON
Authors: Blinks L. R. , Nielsen John P.
Published: May 2004

Analysis of the cell sap of Hydrodictyon patenaeforme Pocock, from California indicates the usual marked accumulation of potassium, which is 4000 times as concentrated as in the surrounding pond water. Small amounts of sodium and calcium were found. Chloride makes up about three-fourths of the anions, with a very high sulfate, and much lower bicarbonate concentration accounting for most of the remainder. Electrical conductivity and osmotic studies indicate that the analyzed elements are ionized, and account for most of the sap's osmotic pressure. pH is 5.5 to 6.0.

The analytical procedure was designed to determine as many of the cations as possible on one small sample.

Hydrodictyon is a large multinucleate cell belonging to an order (Chlorococcales) new to permeability and accumulation studies.
THE COMPOSITION OF FLUIDS AND SERA OF SOME MARINE ANIMALS AND OF THE SEA WATER IN WHICH THEY LIVE
Authors: Cole William H.
Published: May 2004

1. The electrolyte composition, the pH, and freezing points of the fluids of several invertebrates and one primitive chordate are reported.

2. Fluids of the worms, echinoderms, and the clam Venus were isotonic with sea water; fluids of the Arthropoda were hypertonic to sea water.

3. The pH of all fluids was below that of sea water. In the Arthropoda and Myxine less individual variation in pH appeared than in the echinoderms and worms.

4. Ratios of ionic concentrations in the fluid to those in the sea water indicated (1) uniform distribution of ions between the internal and external media for the echinoderms and Venus, (2) differential distribution of potassium and magnesium in the worms; (3) differential distribution of sulfate, magnesium, potassium, and calcium in the Arthropoda; and (4) differential distribution of calcium, magnesium, and sulfate in Myxine.

5. The unequal distribution of ions implies the expenditure of energy against a concentration gradient across the absorbing or excreting membranes, a capacity frequently overlooked in the invertebrates.

6. The sera of the Arthropoda from diluted sea water showed higher concentrations of sodium, potassium, calcium, and chloride ions relative to the respective concentrations in the external medium than in normal sea water, and also showed different orders for those ions.

7. The increase in osmotic pressure of the sera of the animals moving into brackish water is caused by unequal accumulation of sodium, potassium, calcium, and chloride ions. Sulfate and magnesium ionic ratios do not change.
ADSORPTION OF BACTERIOPHAGE UNDER VARIOUS PHYSIOLOGICAL CONDITIONS OF THE HOST
Authors: Delbrück M.
Published: May 2004

1. The adsorption rate constant of phage to bacterium is found to change between wide limits, depending on the physiological state of the bacterium.

2. The experiments of Krueger and of Schlesinger on the residual free phage in contact with an excess of bacteria are discussed and the view of Schlesinger, that they represent phage particles with reduced affinity to the bacterial host is supported by experiments.

3. The theory of von Smoluchowski and Schlesinger is compared with the experiments.

4. The implications of these findings for the assay methods currently used are discussed.
THE GROWTH OF BACTERIOPHAGE AND LYSIS OF THE HOST
Authors: Delbrück M.
Published: May 2004

1. A new strain of B. coli and of phage active against it is described, and the relation between phage growth and lysis has been studied. It has been found that the phage can lyse these bacteria in two distinct ways, which have been designated lysis from within and lysis from without.

2. Lysis from within is caused by infection of a bacterium by a single phage particle and multiplication of this particle up to a threshold value. The cell contents are then liberated into solution without deformation of the cell wall.

3. Lysis from without is caused by adsorption of phage above a threshold value. The cell contents are liberated by a distension and destruction of the cell wall. The adsorbed phage is not retrieved upon lysis. No new phage is formed.

4. The maximum yield of phage in a lysis from within is equal to the adsorption capacity.

5. Liberation of phage from a culture in which the bacteria have been singly infected proceeds at a constant rate, after the lapse of a minimum latent period, until all the infected bacteria are lysed.

6. If the bacteria are originally not highly in excess, this liberation is soon counterbalanced by multiple adsorption of the liberated phage to bacteria that are already infected. This leads to a reduction of the final yield.
STUDIES ON THE CHLOROPHYLLS AND PHOTOSYNTHESIS OF THERMAL ALGAE FROM YELLOWSTONE NATIONAL PARK, CALIFORNIA, AND NEVADA
Authors: Inman O. L.
Published: May 2004

1. Myxophyceae normally growing at 65°C. evolved oxygen upon irradiation and showed evidence of retaining the power to carry on the process of photosynthesis at 20°C. This indicates that extra thermal energy is not essential for photosynthesis at least over a short period of time.

2. Chlorophyll a and b found in several species of Myxophyceae growing in waters ranging in temperature from 37–72°C. are essentially the same as found in plants growing all over the world. Certain standard chemical tests and spectroscopic examination of the chlorophylls were used as the criteria for these comparisons. The ratio of chlorophyll a to b often varied considerably but in general chlorophyll a showed an increase over the percentage found in most plants.

3. Green algae (Chlorella sp.?) were the only forms found at The Geysers, California. The temperature of the waters from which collections were made varied from 49–66°C.

4. Collections from Beowawe, Nevada were from waters ranging from 60–71°C. The algae belonged to the Myxophyceae and the species were like some of those found in Yellowstone National Park.

5. In some of the calcareous regions of Yellowstone National Park spectroscopic study of the chlorophylls revealed an unidentified absorption band at 548 mµ.
THE FLICKER RESPONSE CURVE FOR FUNDULUS
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

After Fundulus heteroclitus have been for some time in the laboratory, under conditions favorable for growth, and after habituation of the fishes to the simple routine manipulations of the observational procedure required, they are found to give reproducible values of the mean critical flash illumination (Im) resulting in response to visual flicker. The measurements were made with equality of light time and dark time in the flash cycle, at 21.5°C.

Log Im as a function of flash frequency F has the same general form as that obtained with other fishes tested, and for vertebrates typically: the curve is a drawn-out S, with a second inflection at the low I end.

In details, however, the curve is somewhat extreme. Its composite form is readily resolved into the two usual parts. Each of these expresses a contribution in which log I, as a function of F, is accurately expressed by taking F as the summation (integral) of a probability distribution of d log I, as for the flicker response contour of other animals.

As critical intensity I increases, the contribution of rod elements gradually fades out; this decay also adheres to a probability integral.

The rod contribution seen in the curve for Fundulus is larger, absolutely and relatively to that from the cones, than that found with a number of other vertebrates. The additive overlapping of the rod and cone effects therefore produces a comparatively extreme distortion of the resulting F-log I curve.

The F-log Im curve is shifted to lower intensities as result of previous exposure to supranormal temperatures. This effect is only very slowly reversible. The value of Fmax. for each of the components of the duplex curve remains unaffected. The rod and cone segments are shifted to the same extent. The persisting increase of excitability thus fails to reveal any chemical or other differentiation of the excitability mechanism in the two groups of elements.

Certain bearings of the data upon the theory of the flicker response contour are discussed, with reference to the measurements of variation of critical intensity and to the form of the F-log I curve. The quantitative properties of the data accord with the theory derived from earlier observations on other forms.
SUMMATION OF ELECTRICAL POTENTIAL OF LIVING MEMBRANES (FROG SKIN): A MODEL OF THE ELECTRICAL ORGAN OF FISHES
Authors: Barnes T. Cunliffe
Published: May 2004

Frog skins arranged "in series" in tubes of Ringer's solution exhibit summation of electrical potential which helps to explain the nature of electrical fields in the organism as a whole and in the electrical organ of fishes.

See PDF for Structure
ELECTROPHORETIC HOMOGENEITY OF PREGNANT MARE SERUM GONADOTROPHIN
Authors: Li Choh Hao , Evans Herbert M. , Wonder Donald H.
Published: May 2004

A highly purified and potent gonadotrophin in pregnant mare serum has been prepared. The preparation has been shown to be electrophoretically homogeneous in the Tiselius apparatus. The mobilities of the substance have been determined over a wide range of hydrogen ion concentrations.

The isoelectric point lies at pH 2.60–2.65 and the value of

See PDF for Equation

is 4.0 x 10–5.

Some chemical constituents have been studied. From the tryptophane and tyrosine content the molecular weight of the hormone is estimated to be 30,000.

The hormone has been subjected to acetylation by ketene in aqueous solution at room temperature and the result suggests again the essentiality of free amino groups for the biological activity of the hormone. In this respect it is to be contrasted with human chorionic gonadotrophin.
SEPARATION OF POTASSIUM ISOTOPES IN VALONIA AND NITELLA
Authors: Jacques A. G.
Published: May 2004

The ratio of K39 ÷ K41 appears to be lower in the sap of Valonia and Nitella than in the environment, indicating that the living cell can separate these isotopes to some extent.

Experiments with a mixture of guaiacol and p-cresol suggest that a similar separation may occur here but further experiments are needed.
CRYSTALLINE RIBONUCLEASE
Authors: Kunitz M.
Published: May 2004

1. A crystalline enzyme capable of digesting yeast nucleic acid has been isolated from fresh beef pancreas.

2. The enzyme called "ribonuclease" is a soluble protein of albumin type. Its molecular weight is about 15,000. Its isoelectric point is in the region of pH 8.0.

3. Ribonuclease splits yeast nucleic acid into fragments small enough to diffuse readily through collodion or cellophane membranes.

4. The split products of digestion, unlike the undigested yeast nucleic acid, are not precipitable with glacial acetic acid or dilute hydrochloric acid.

5. The digestion of yeast nucleic acid is accompanied by a gradual formation of free acid groups without any significant liberation of free phosphoric acid.

6. Ribonuclease is stable over a wide range of pH even when heated for a short time at 100°C. Its maximum stability is in the range of pH 2.0 to 4.5.

7. Denaturation of the protein of ribonuclease by heat or alkali, or digestion of the protein by pepsin, causes a corresponding percentage loss in the enzymatic activity of the material.
STUDIES ON PHOTOSYNTHESIS
Authors: Myers Jack , Burr G. O.
Published: May 2004

1. The effect on oxygen evolution of Chlorella vulgaris produced by light intensities up to about 40,000 f.-c. has been studied by the use of the Warburg technique.

2. Above a certain critical intensity, which is determined by the previous history of the cells, the rate of oxygen evolution decreases from the maximum to another constant rate. This depression is at first a completely reversible effect.

3. With a sufficiently high intensity this constant rate represents an oxygen uptake greater than the rate of dark respiration. During such a constant rate of oxygen uptake a progressive injury to the photosynthetic mechanism takes place. After a given oxygen consumption the rate falls off, approaching zero, and the cells are irreversibly injured.

4. The constant rate of oxygen evolution (2 and 3) decreases in a continuous manner with increasing light intensities, approaching a value which is approximately constant for all lots of cells regardless of previous history.

5. Two alternative hypotheses have been presented to explain the observed phenomena. The more acceptable of these proposes quick inactivation of the photosynthetic mechanism, the extent of inhibition depending on the light intensity.

6. In Chlorella vulgaris solarization is influenced by the previous history of the cells.
THE EXPERIMENTAL PRODUCTION OF DOUBLE PEAKS IN CHARA ACTION CURVES AND THEIR RELATION TO THE MOVEMENT OF POTASSIUM
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

The action curve in Chara seems to depend (as in Nitella) on the outward movement of K+ from the sap.

Presumably the increase in permeability in the inner protoplasmic surface and the outward movement of K+ destroy the concentration gradient of K+ across the inner protoplasmic surface. Hence the outwardly directed P.D. disappears, causing the rise (spike) of the action curve.

The outer protoplasmic surface is normally insensitive to K+. But when it is made sensitive to K+ by treatment with guanidine the outwardly moving K+ sets up a positive P.D. on reaching the outer surface and this causes the action curve to fall, producing a peak. Then the curve has 2 peaks, the second being due to the process of recovery.

The action curve thus comes to resemble that of Nitella in which the outer protoplasmic surface is normally sensitive to K+.
KINETICS OF THROMBIN INACTIVATION AS INFLUENCED BY PHYSICAL CONDITIONS, TRYPSIN, AND SERUM
Authors: Glazko Anthony J. , Ferguson John H.
Published: May 2004

1. A new technique for studying the progressive inactivation of thrombin is described.

2. Thrombin inactivation follows the kinetics of a first order reaction.

3. The rate constant of the inactivation reaction increases with temperature and pH (5.0 → 10.0), and also with the presence of crystalline trypsin, or serum. The rate varies for different thrombin preparations, even under the same experimental conditions.

4. The temperature characteristics of the reaction indicate that thrombin is associated with protein.

5. Thrombin preparations are most stable at pH 4 to 5, even when trypsin or serum is added.

6. The progressive inactivation is believed to be due to two mechanisms: (1) a major effect, thought to be the action of a "serum-tryptase," which is usually present in the thrombin preparations, and (2) a minor effect, probably attributable to denaturation of thrombin-protein.

7. Sources of the thrombinolytic factor (serum-tryptase) and its implications in the general theory and practical problems of blood coagulation and antithrombic action are briefly discussed.
THE USE OF SOLUBILITY AS A CRITERION OF PURITY OF PROTEINS
Authors: Butler J. A. V.
Published: May 2004

1. The conditions under which the phase rule may be applied to systems containing proteins are formulated.

2. An attempt was made to fractionate chymotrypsinogen, by crystallization in stages with increasing concentration of magnesium sulfate. No significant fractionation of the protein was achieved, but a small amount of impurity which affects the solubility, while having little influence on other properties of the material, was concentrated in the fractions first precipitated.

3. The solubility of the final fraction was independent of the amount of the saturating solid, from the first appearance of a solid phase, in solvents of three different pH's. The solubility was independent of the environment in which the crystals were formed (within the limits in which crystallization can be carried out) and the same value was reached from the supersaturated as from the undersaturated side. This material, therefore, conforms closely with the phase rule criteria of a pure protein.