bluuebunny/crossref_metadata_2025_split huggingface dataset:
STIMULATION OF FUNDULUS BY OXALIC AND MALONIC ACIDS AND BREATHING RHYTHM AS FUNCTIONS OF TEMPERATURE
Authors: Sizer Irwin W. 
Published: May 2004

1. Chemical stimulation as a function of temperature was studied by using oxalic acid in fresh and salt water and malonic acid in salt water as stimulating agents on Fundulus. According to the Arrhenius equation the following µ values were obtained for the various acid solutions between 0 and 29°C.: for 0.002N oxalic in fresh water—15,800; 33,000; for 0.0008N oxalic in fresh water—15,800; 33,000; 48,000; for 0.002N oxalic in salt water—19,400; 24,100; 56,500; for 0.004N and 0.002N malonic in salt water—20,600; 65,000. At a critical temperature there is a sharp transition from one thermal increment to another.
2. The chemical processes controlling stimulation do not change with concentration, for different normalities of a single acid yield the same µ values. Distinctly different temperature characteristics were obtained for stimulation by oxalic in salt and fresh water. Likewise stimulation by oxalic and malonic in salt water yielded very different increments. This temperature study indicates that the controlling chemical reactions determining rate of response are different for the same acid in two different environments, or for two dibasic acids in the same environment. Other work indicates, however, that the fundamental stimulation system is the same for all the adds in both environments. Chemical rather than physical processes limit the rate of response since all the values are above 15,000. Stimulation depends upon a series of interrelated chemical reactions, each with its own temperature characteristic. Under varying conditions (e.g. change of temperature, environment, or acid) different chemical reactions may become the slowest or controlling process which determines the rate of response.
3. The variation of response, as measured by the probable error of the mean response time of the fish, is the same function of temperature as reaction time itself. Hence variability is not independent of reaction time and is controlled by the same catenary series of events which determine rate of response to stimulation.
4. Breathing rhythm of Fundulus as related to temperature was studied in both salt and fresh water. In salt water the temperature characteristic is 8,400 while in fresh water it is 16,400 below 9.5°C., and 11,300 above this critical temperature. These µ values are typical of those which have been reported by other workers for respiratory and oxidative biological phenomena. A change in thermal increment with an alteration in environment indicates that different chemical reactions with characteristic velocity constants are controlling the breathing rhythm in salt and fresh water.
EFFECT OF PROTEINS ON ELECTROPHORETIC MOBILITY AND SEDIMENTATION VELOCITY OF RED CELLS
Authors: Monaghan B. R. , White H. L. 
Published: May 2004

The isoelectric point of normal red cells cannot be measured but is certainly lower than that of any plasma protein. Red cells are easily damaged so that they will adsorb proteins from low concentrations. Normal red cells do not adsorb protein even from concentrated solutions, as is evidenced by the finding that the ratio of the mobility of the cells to that of the proteins themselves is at least as high in concentrated casein, albumin, gelatin, or fibrinogen solutions as in dilute.
The finding that the observed mobility of red cells is unchanged or only slightly decreased when bulk viscosity is increased by added protein is interpreted as indicating that the red cell surfaces are hydrated. The aggregating effect of certain proteins has been determined and is assumed to be due to their dehydrating effect on the cells. Some types of cells, as beef, are not aggregated, presumably because they are resistant to this dehydrating effect. The difference in the behavior of different types of red cells demonstrates the importance of the nature of the cell as well as of the medium in determining the rate of aggregation and therefore of sedimentation.
THE KINETICS OF THE REACTION WHICH TAKES PLACE BETWEEN IODOACETIC ACID AND GLYCINE
Authors: Brdička R. 
Published: May 2004

1. The kinetics of the reaction which takes place between glycine and iodoacetic acid was studied by means of the polarographic method.
2. On the basis of kinetic equations, evidence was obtained that (a) The reaction proceeds in two steps in which the hydrogens of the amino group are consecutively replaced by the acetyl radicals, the velocity constants being in the ratio 2:1. (b) Only the anionic form of glycine is able to react since the velocity constants at any pH are proportional to the concentration of glycine anion. (c) The reaction is of the ionic type, showing a positive salt catalysis, which, according to Brönsted's hypothesis, involves the primary and the secondary salt effects.
3. The fact that only the glycine anion is able to react was explained as being due to the existence of an unbonded pair of electrons on the nitrogen in the NH2 group. The NH3+ group, however, in which these electrons are shared by H+, must, therefore, be inactive.
THE ADSORPTION OF EGG ALBUMIN ON COLLODION MEMBRANES
Authors: Dow Philip 
Published: May 2004

An experimental study has been made of the adsorption of purified egg albumin, from aqueous solution, on collodion membranes. At protein concentrations of 4 to 7 per cent apparent saturation values were obtained which resembled closely the results obtained with gelatin, showing a maximum at pH 5.0 and lower values on either side of this region. Over large ranges of protein concentration, however, the curves for the adsorption from solutions removed in either direction from the isoelectric point exhibited a different shape from the hyperbola obtained in the neighborhood of pH 5.0. The addition of NaCl to solutions on the acid side tended to obliterate the effect of the pH difference; on the alkaline side it greatly increased the adsorption. The adsorption at 25° was about twice as great as that at 1°.
The theory of the swelling of submicroscopic particles, advanced to account for the adsorption behavior of gelatin, is not sufficient to explain the results obtained with egg albumin. It is suggested that the effect is related to alterations in the forces causing the retention of the protein on the membranes.
THE GROWTH AND RESPIRATION OF THE AVENA COLEOPTILE
Authors: Bonner James 
Published: May 2004

1. Transport of the plant growth hormone into the Avena coleoptile as well as the action of the hormone on cell elongation in the coleoptile are shown to depend upon aerobic metabolism.
2. Crystalline auxine, in contrast with impure preparations, affects neither the magnitude nor the respiratory quotient of coleoptile respiration.
3. Increasing age of the coleoptile cell decreases its rate of elongation much more than its rate of respiration. HCN or phenylurethane on the other hand decrease the two processes to the same extent, in spite of the fact that only a small portion of the energy liberated by respiration can be used in the mechanical process of growth.
4. From 2 and 3 it is concluded that processes of a respiratory nature but of relatively small magnitude form one or more integral steps in the chain of reactions by which the plant growth hormone brings about cell elongation.
STUDIES ON CELL METABOLISM AND CELL DIVISION
Authors: Krahl M. E. , Clowes G. H. A. 
Published: May 2004

The dihalo and trihalophenols, and phenols containing both halo and nitro substituents in the same molecule, produce, in fertilized eggs of Arbacia punctulata, a rise in rate of oxygen consumption and a reversible block to cell division. To define the conditions which affect the degree of this activity, the following factors have been varied: the arrangement of substituents in the molecule, the concentration of reagent, and the time after fertilization at which the reagent is added.
The stimulation of oxygen consumption and reversible block to cell division produced by the dihalophenols are qualitatively the same as those previously produced in fertilized Arbacia eggs by certain dinitrophenols. To yield optimum respiratory effect and maximum division block, it usually requires a higher concentration of dihalo than of the corresponding dinitrophenol. For example, with fertilized Arbacia eggs at 20°C. 2,4-dinitrophenol, in optimum concentration of 3 x 10–5 molar, raises oxygen consumption to 292 per cent of normal (4). The corresponding values for two dihalo analogues are: 2,4-dichlorophenol, 10–4 molar and 236 per cent; 2,4-dibromophenol, 6 x 10–5 molar and 282 per cent.
The halophenols differ from the nitrophenols in two interesting respects: (a) The monohalophenols produce little or no oxidative stimulation or division block in fertilized Arbacia eggs; p-nitrophenol is very active in both respects. (b) The symmetrical trihalophenols have an appreciable ability to stimulate oxygen consumption and block division; symmetrical trinitrophenol is inactive in both respects (4).
The increases in oxygen consumption produced in fertilized Arbacia eggs by 2,4-dichloro and 2,4-dinitrophenol are larger than the percentage increases given by methylene blue and o-cresol indophenol under the same experimental conditions. The dihalo and dinitrophenols produce a reversible block to the cell division of fertilized marine eggs. The oxidation-reduction indicators, in contrast to the dihalo and dinitrophenols, block cell division irreversibly and fertilized eggs of Arbacia do not recover from optimum respiratory stimulating concentrations of these oxidation-reduction dyes.
The present experiments with halophenols are in harmony with and lend considerable support to the hypothesis (4) that nitro and similarly substituted phenols derive their biological activity from the presence and properties of the phenolic OH group, as modified by proper substitution in the phenolic benzene ring.
THE EFFECT OF HEMOLYTIC SUBSTANCES ON WHITE CELL RESPIRATION
Authors: Ponder Eric , Macleod John 
Published: May 2004

Substances such as saponin, the bile salts, etc., which produce lysis of red cells also produce cytolysis of white cells from rabbit peritoneal exudates, the arbitrary criterion of their cytolytic effect being their ability to depress the O2 consumption of the leucocytes. The amount of cytolysis increases regularly as the amount of the added lysin is increased, and sufficiently large quantities of saponin, sodium taurocholate, sodium glycocholate, or sodium oleate are capable of virtually abolishing the O2 consumption altogether. At the same time, it can be shown that a lysin such as saponin is used up in combining with the white cells in much the same way as it is used up in combining with red cells, and the reduction in oxygen consumption appears to be roughly proportional to the amount so combined. The action of these lytic substances on white cells, in fact, is very similar to their action on red cells, due allowance being made for the fact that the cytolysis of the white cell is probably not an all-or-none process like hemolysis.
White cell respiration is also depressed in hypotonic solutions, the respiration being virtually linear with the tonicity.
GROWTH SUBSTANCE CURVATURES OF AVENA IN LIGHT AND DARK
Authors: Van Overbeek J. 
Published: May 2004

An attempt has been made to analyze the base response, one of the light growth responses of Avena coleoptiles, by means of growth substance curvatures. The decrease in growth rate (first part of the base response) after exposure to light does not show if hetero-auxin is substituted for auxin-a (Sections 5, 6, and 10). This decreased growth after exposure very likely is due to an oxidative inactivation of auxin-a (Sections 8 and 9). Hetero-auxin can be inactivated too but in a much lesser degree than auxin-a (Section 9). The increase in growth rate following on the decreased growth (second part of the base response) is due to an increase in response of the plant to growth hormone which is independent of the type of hormone (Sections 1, 2, 7, 8, and 10). Under conditions of continuous exposure to light, however, the inactivation of the auxin-a under influence of the light is superimposed on this increased response to growth hormone. This inactivation can be eliminated from the light growth response by replacing the auxin-a by hetero-auxin. More detailed information on this subject can be found in Section 10. A review of the experiments and their results can be obtained from the scheme in Section 8.
In Section 11 it is shown that light inhibits the formation of growth hormone in the decapitated coleoptile (regeneration). Very small amounts of light (25 m.c.s.) inhibit the regeneration markedly.
INACTIVATION OF PEPSIN BY IODINE AND THE ISOLATION OF DIIODO-TYROSINE FROM IODINATED PEPSIN
Authors: Herriott Roger M. 
Published: May 2004

In the presence of iodine at pH 5.0–6.0 a solution of pepsin absorbs iodine and the specific proteolytic activity of the solution decreases. The activity is less than 1 per cent of the original activity when the number of iodine atoms per mol of pepsin is 35–40.
If the pH is 4.5 or less, iodine reacts very slowly and there is a correspondingly slower loss in activity. Glycyl tyrosine reacts with iodine in a manner similar to pepsin.
Experiments were performed to determine the extent to which oxidation of pepsin by iodine occurs during iodination, and if such oxidation were responsible for the loss in enzymatic activity. Although the results were not absolutely decisive, there seems to be no appreciable oxidation taking place during iodination and no relationship between the slight oxidation and loss in peptic activity.
From a dialyzed preparation of completely iodinated pepsin which was inactive and contained 13.4 per cent bound iodine, 82 per cent of the iodine was obtained in a solution which analyzed as a solution of diiodo-tyrosine. Because of the presence of a material which contained no iodine and prevented quantitative crystallization, only 53 per cent of the iodine containing substance could be crystallized. This 53 per cent was, however, identified as diiodo-tyrosine.
The part of the titration curve which in pepsin and most proteins represents the phenolic group of tyrosine was, in the curve for iodinated pepsin, shifted toward the acid region as expected.
From these results, it appears that the loss in proteolytic activity of pepsin, when treated with iodine under the specified conditions, is due to the reaction of the iodine with the tyrosine in pepsin.
CRITICAL ILLUMINATION AND CRITICAL FREQUENCY FOR RESPONSE TO FLICKERED LIGHT, IN DRAGONFLY LARVAE
Authors: Crozier W. J. , Wolf Ernst , Zerrahn-Wolf Gertrud 
Published: May 2004

Curves relating flicker frequency (F) to mean critical illumination (Im) for threshold response to flickered light, with equal durations of light and no light intervals, and relating illumination (I) to mean critical flicker frequency (Fm) for the same response, have been obtained from homogeneous data based upon the reactions of dragonfly larvae (Anax junius). These curves exhibit the properties already described in the case of the fish Lepomis. The curve for Fm lies above the curve of Im by an amount which, as a function of I, can be predicted from a knowledge either of the variation of Im or of Fm. The law of the observable connection between F and I is properly expressed as a band, not as a simple curve.
The variation of Im (and of Fm) is not due to "experimental error," but is an expression of the variable character of the organism's capacity to exhibit the reaction which is the basis of the measurements. As in other series of measurements, P.E.I is a rectilinear function of Im; P.E.F passes through a maximum as F (or I) increases. The form of P.E.F as a function of I can be predicted from the measurements of P.E.I.
It is pointed out that the equations which have been proposed for the interpretation of curves of critical flicker frequency as a function of intensity, based upon the balance of light adaptation and dark adaptation, have in fact the character of "population curves;" and that their contained constants do not have the properties requisite for the consistent application of the view that the shape of the F - I curve is governed by the steady state condition of adaptation.
These curves can, however, be understood as resulting from the achievement of a certain level of difference between the average effect of a light flash and its average after effect during the dark interval.
SOME REMARKS ON THE PHOTOSYNTHESIS OF GREEN PLANTS
Authors: Weiss Joseph 
Published: May 2004

1. It is suggested that in the assimilation process of green plants the reduction of the CO2 takes place with the help of Fe++ ions (present in the chloroplast) under the influence of light, which is absorbed by a sensitizing chlorophyll-CO2-complex.
2. It seems that the chlorophyll has to fulfill two different functions depending on its situation in the chloroplast. The chlorophyll molecules on the surface of the lipoid phase (in contact with an aqueous phase containing Fe++) combine with CO2 to form a light absorbing chlorophyll-CO2-complex and in this way take part in the reduction of the CO2.
The light energy is also absorbed by the greater portion of the chlorophyll, which is dissolved in the interior of the lipoid phase, and eventually handed over to the chlorophyll molecules on the surface.
3. The photosynthetic unit of Emerson and Arnold may be determined by the ratio:
See PDF for Equation
so that for every chlorophyll molecule on the surface there are about 500 molecules in the interior, which provide it with the necessary quanta.
STUDIES IN BLOOD COAGULATION
Authors: Eagle Harry , Harris Tzvee N. 
Published: May 2004

Crude or crystalline trypsin in proper concentration causes the blood or plasma of human beings, dogs, rabbits, guinea pigs, and horses to coagulate. It does not clot the fibrinogen directly, but reacts with prothrombin to form thrombin. Since trypsin thus has the same effect as the physiological system Ca plus platelets (or Ca plus tissue extracts), it is suggested as a tentative working hypothesis that the latter system contains a proteolytic enzyme with a specific affinity for prothrombin. Other implications of this trypsin effect with respect to the mechanism of physiological coagulation are discussed in the text (pages 557–558).
The proteolytic enzyme papain also coagulates blood. In this case the enzyme does not activate prothrombin, but acts directly on fibrinogen to form a fibrillar gel resembling fibrin. If one admits this clot to be fibrin, this constitutes strong evidence that thrombin, the physiological coagulant, is also a proteolytic enzyme with a specific action on fibrinogen.
ACTION OF ULTRAVIOLET LIGHT ON SPORES AND VEGETATIVE FORMS OF B. MEGATHERIUM SP
Authors: Herčík Ferdinand 
Published: May 2004

Spores and vegetative forms of a strain of B. megatherium were irradiated by ultraviolet light of the wave lengths 2536 Å, 2803 Å, and 3132 Å. The killing rate of both bacteria and spores is exponential, in agreement with irradiation results on other bacteria. Twice as much incident energy is needed to kill the spores as the vegetative forms (50 per cent death).
The absorbed energy per bacterium for 50 per cent killing has been calculated on the assumption that the absorption of the vegetative cells is the same as that of colon bacilli. These results are compared with previous measurements on other bacteria.
SUBSTANCES AFFECTING ADULT TISSUE IN VITRO
Authors: Simms Henry S. , Stillman Nettie P. 
Published: May 2004

Adult tissue is characterized by a lag period of several days preceding the onset of growth in vitro.
Treatment of fresh adult tissues with trypsin before planting them in culture flasks stimulated the tissues to grow sooner and more rapidly.
Best stimulation was obtained by slow digestion at low temperature. The tissues lost nitrogen during the digestion. Lowering the temperature from 22°C. to 5°C. reduced the digestion of aorta tissue much less than it reduced the digestion of casein.
Washing the tissue after trypsin treatment resulted in better stimulation.
Trypsin solutions of different degrees of purity, when diluted to equal activity toward casein, gave equal stimulation to the tissue growth. These included solutions of Northrop's crystalline trypsin and chymo-trypsin.
Papain also stimulated growth in a similar manner.
The results indicate that this stimulation of tissue growth is due entirely to proteolytic action.
Cultures of adult fibroblasts (and some tumor cultures) having reached a state of retarded growth have been treated with trypsin to digest away most of the plasma clot (used as a medium). Fresh plasma has been added to renew the clot. This treatment has resulted in an immediate renewal of growth.
Reasons are given for supposing that the cells produce an inhibitor in vitro which they deposit in the surrounding clot, and which is removed by the action of trypsin.
CHANGES OF APPARENT IONIC MOBILITIES IN PROTOPLASM
Authors: Osterhout W. J. V. 
Published: May 2004

The normal P.D. across the protoplasm of Valonia macrophysa is about 10 mv. negative (inwardly directed). On adding 0.01 M guaiacol to the sea water the P.D. becomes positive and then slowly returns approximately to the normal value.
In many cases this behavior is not much affected by raising the pH and so increasing the concentration of the guaiacol ion but in other cases such an increase makes the P.D. somewhat more negative.
But if we wait until the exposure to guaiacol has lasted 5 minutes (and the P.D. has returned to its normal value) before we raise the pH, the result is very different. The cell then behaves as though it had been sensitized to the action of the guaiacol ion which appears to be far more effective than undissociated guaiacol in making the P.D. more positive. This may be due in part to the high apparent mobility of the guaiacol ion and in part to alterations which it produces in the protoplasm (such alterations increase the P.D. across the protoplasm whereas ordinary injury would be expected to lower it and the cells live on after this treatment and show no signs of injury).
This action of the guaiacol ion is in marked contrast to the behavior of other anions whose effect resembles that of Cl-.
POLARIZATION STUDIES IN COLLODION MEMBRANES AND IN SYNTHETIC PROTEIN-LIPOID MEMBRANES
Authors: Spiegel-Adolf Mona 
Published: May 2004

1. Collodion membranes of high polarizability and low resistance can be obtained either by addition of certain ether-soluble substances such as phosphatides, olive oil, mastix, and gum benzoin, to the collodion or by drying collodion membranes for a limited time under pressure.
2. The permeability of membranes of different polarization has been measured by means of conductivity methods.
3. Sintered glass filter plates of Jena glass crucibles on which proteins and lipoids have been adsorbed show polarization. It could be shown that some narcotics which react with lecithin cause an increase in polarization of the protein-lipoid-glass system. Substitutions of the protein but not of the lipoid were possible, without causing a decrease in the polarizability of the membranes.