bluuebunny/crossref_metadata_2025_split huggingface dataset:
ACCUMULATION OF SALT AND PERMEABILITY IN PLANT CELLS
Authors: Hoagland D. R. , Broyer T. C. 
Published: May 2004

1. Comparisons are made of concentrations of K and Br in exudates of barley roots and in expressed sap from roots, under conditions favorable for aerobic metabolism. Both methods lead to the same general viewpoint concerning metabolically governed transport of solutes by living plant cells.
2. Cyanide in low concentration prevented salt accumulation by barley roots. Methylene blue, without decrease of CO2 production by roots, destroyed power of salt accumulation.
3. K and Br ions entered roots to only a slight extent under an anaerobic condition, even with an inward gradient of ionic concentration.
4. Lactate or alcohol, under aerobic conditions, did not prevent rapid accumulation of salt by root cells.
5. Experiments on fluids obtained by suction from tomato roots gave evidence of loss of salt-accumulating power under the influence of N2 gas or CO2 gas, together with probable effects on cell permeability.
6. Several experiments on Nitella cells in which radioactive isotopes were used are reported. Bromide gradually moved into vacuolar sap until the concentration appeared to exceed that of the protoplasm, on the basis of the results of the several types of experiments. Accumulation of salt in the vacuole did not occur anaerobically.
7. Some views of interrelations of permeability, salt accumulation, and metabolism are suggested for further discussion.
FERMENTATIVE AND PHOTOCHEMICAL PRODUCTION OF HYDROGEN IN ALGAE
Authors: Gaffron Hans , Rubin Jack 
Published: May 2004

1.. After 2 hours of fermentation in nitrogen the metabolism of those algae which were found capable of photoreduction with hydrogen changes in such a way that molecular hydrogen is released from the cell in addition to carbon dioxide.
2. The amount of hydrogen formed anaerobically in the dark depends on the amount of some unknown reserve substance in the cell. More hydrogen is formed in presence of added glucose, but no proportionality has been found between the amount of substrate added and that of hydrogen formed. This is probably due to the fact that two types of fermentation reactions exist, with little or no connection between them. Whereas mainly unknown organic acids are formed during the autofermentation, the addition of glucose causes a considerable increase in the production of lactic acid.
3. Algae which have been fermenting for several hours in the dark produce upon illumination free hydrogen at several times the rate observed in the dark, provided carbon dioxide is absent.
4. Certain concentrations of dinitrophenol strongly inhibit the evolution of hydrogen in the dark. Fermentation then continues mainly as a reaction leading to lactic acid. In such poisoned algae the photochemical liberation of hydrogen still continues.
5. If the algae are poisoned with dinitrophenol the presence of carbon dioxide will not interfere with the photochemical evolution of hydrogen.
6. The amount of hydrogen released in this new photochemical reaction depends on the presence of an unknown hydrogen donor in the cell; it can be increased by the addition of glucose but not in proportion to the amount added.
7. The results obtained allow for a more correct explanation of the anaerobic induction period previously described for Scenedesmus and similar algae. The possibility of a photochemical evolution of hydrogen had not been taken into account in the earlier experiments.
8. The origin of the hydrogen released under the influence of light is discussed.
SEDIMENTATION IN THE ANGLE CENTRIFUGE
Authors: Pickels Edward G. 
Published: May 2004

1. Using hemocyanin from Limulus polyphemus as a test material, the process of sedimentation in the angle centrifuge, operating both in vacuum and in the open air, has been investigated.
2. Sedimentation in a given field of force was found less efficient when centrifugation was conducted in the open air, because of thermal convection.
3. Correlations have been made with results obtained in the analytical ultracentrifuge, and a theory of sedimentation in inclined tubes has been presented to explain the experimental results.
4. It has been shown that under proper conditions the angle centrifuge may be used for approximate determinations of particle size.
5. Recommendations, based mostly on experimental evidence, have been made for improving sedimentation and interpreting results.
6. To counteract convective disturbances of either thermal or inertial origin, a satisfactory method has been developed which consists of furnishing the fluid under study with a synthetic density gradient, formed with sucrose or some other non-sedimentable material.
THE ANTIPROTEOLYTIC ACTIVITY OF SERUM
Authors: Grob David 
Published: May 2004

1. Heating diluted serum at 80° C. for 10 minutes made it a better medium for bacterial growth. This is believed to have been at least partly due to destruction of the serum antiprotease.
2. Growth was accelerated, and proceeded further, in the presence of trypsin.
3. Growth was somewhat retarded in the presence of pancreatic trypsin inhibitor.
4. The bacteriostatic action of sulfathiazole in serum was reduced by heating the serum at 80° C., and much more markedly (in any of the media studied) by adding trypsin. It was greater in serum and albumen than in peptone and meat infusion.
5. The significance of the experimental results was considered in relation to the possible influence of leucoprotease and of serum antiprotease on bacterial growth and sulfonamide action.
STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES
Authors: Potter V. R. , Albaum H. G. 
Published: May 2004

1. The effect of ribonuclease on various enzyme systems was studied as one approach to the problem of whether or not these enzymes are contained in macromolecules of ribonucleoprotein nature in protoplasm.
2. Ribonuclease inhibited CoI-cytochrome c reductase, succinic dehydrogenase, and cytochrome oxidase, all of which require cytochrome c in order to function. Ribonuclease did not act on cytochrome c.
3. Ribonuclease did not inhibit urease, xanthine oxidase, catalase, alkaline phosphatase, or adenosine triphosphatase under the conditions employed.
4. It was suggested that ribonuclease acted sterically by preventing contact between cytochrome c and its activating centers.
5. It was suggested that the enzymes inhibited may be contained in a ribonucleoprotein of macromolecular dimensions but that the enzymes not inhibited are not necessarily excluded from such a complex by the data presented.
6. Further evidence against the Szent-Györgyi theory of hydrogen transport was presented and discussed.
PHYSICAL PROPERTIES OF THE ALLANTOIC AND AMNIOTIC FLUIDS OF THE CHICK
Authors: Walker Paul Andrew 
Published: May 2004

1. The hydrogen ion concentration of the allantoic and amniotic fluids of the developing chick has been determined over the period of incubation between the 7th and 19th days using the glass electrode technique.
2. Changes in this property have been related to changes in the chemical composition of these two fluids.
3. The results of this investigation have been compared with those obtained by other workers. Excellent confirmation has been afforded the work of Yamada, whereas the work of Aggazzotti, which has long been accepted, is shown to be in error.
AN EXPERIMENTAL SEPARATION OF OXYGEN LIBERATION FROM CARBON DIOXIDE FIXATION IN PHOTOSYNTHESIS BY CHLORELLA
Authors: Fan C. S. , Stauffer J. F. , Umbreit W. W. 
Published: May 2004

Using intact cells of Chlorella pyrenoidosa it is possible to obtain oxygen by the reduction of certain reducible materials other than carbon dioxide. Of these, benzaldehyde was studied in some detail. This reduction does not involve the production of carbon dioxide from the benzaldehyde. Stoichiometrical relationships as expressed by the following equation:
2C6H5CHO + 2H2O → 2C6H5CH2OH + O2 are somewhat difficult to obtain because the benzaldehyde can disappear from the reaction mixtures by dark reactions. The technique is now available which permits detailed studies of the oxygen-liberating mechanisms in photosynthesis.
ON THE INACTIVATION OF ASCORBIC ACID OXIDASE
Authors: Powers Wendell H. , Dawson Charles R. 
Published: May 2004

1. In the absence of protective agents, highly purified ascorbic acid oxidase is rapidly inactivated during the enzymatic oxidation of ascorbic acid under optimum experimental conditions. This inactivation, called reaction inactivation to distinguish it from the loss in enzyme activity that frequently occurs in diluted solutions of the oxidase prior to the reaction, is indicated by incomplete oxidation of the ascorbic acid as measured by oxygen uptake; i.e., "inactivation totals."
2. A minor portion of the reaction inactivation appears to be due to environmental factors such as rate of shaking of the manometers, pH of the system, substrate concentration, and oxidase concentration. The presence of inert protein (gelatin) in the system ameliorates the environmental inactivation to a considerable extent, and variation of the above factors in the presence of gelatin has much less effect on the inactivation totals than in the absence of gelatin.
3. A major portion of the reaction inactivation of the oxidase appears to be due to some factor inherent in the ascorbic acid-ascorbic acid oxidase-oxygen system, possibly a highly reactive "redox" form of oxygen other than H2O2 or H2O. The inactivation cannot be attributed to dehydroascorbic acid, the oxidation product of ascorbic acid.
4. Small amounts of native catalase, native peroxidase, native or denatured methemoglobin, and hemin when added to the system, markedly protect the oxidase against inactivation. Cytochrome c has no such protective action. Likewise proteins such as egg albumin, gelatin, denatured catalase, or denatured peroxidase show no such protective action.
5. None of the protective agents mentioned above affect the initial rate of oxygen uptake or change the total oxygen absorbed for complete oxidation of the ascorbic acid, and hence do not act by removal of hydrogen peroxide, per se.
6. Sodium azide and hydroxylamine hydrochloride which inhibit catalase and peroxidase activity also inhibit the protective action of these iron-porphyrin enzymes.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Beck Paul W. 
Published: May 2004

1. Dried collodion membranes are known to swell in water and to the same limited extent also in solutions of strong inorganic electrolytes (Carr and Sollner). The present investigation shows that in solutions of organic electrolytes and non-electrolytes, the swelling of dried collodion membranes is not as uniform, but depends on the nature of the solute.
2. The solutions of typically "hydrophilic" substances, e.g., glycerine, glucose, and citric acid, swell collodion membranes only to the same extent as water and solutions of strong electrolytes.
In solutions of typically carbophilic substances (e.g., butyric acid, valeric acid, isobutyl alcohol, valeramide, phenol, and m-nitrophenol) the swelling of the membranes is much stronger than in water, according to the concentration used. For the brand of collodion used the swelling in 0.5 M solution was in some cases as high as 26 per cent of the original volume, as compared to 6 to 7 per cent in water. Therefore, in these solutions the "water-wetted dried" collodion membrane is not rigid, inert, and non-swelling, but behaves as a swelling membrane.
3. The solutes which cause an increased swelling of the membranes are accumulated in the latter, the degree of accumulation being markedly parallel with the degree of their specific swelling action.
4. The anomalously high permeabilities of certain carbophilic organic solutes reported by Michaelis, Collander, and Höber find an explanation in the specific interaction of these substances with collodion.
5. The use of the collodion membrane as a model of the ideal porous membrane is restricted to those instances in which no specific interaction occurs between the solute and the collodion.
THE EFFECTS OF URETHANE AND CHLORAL HYDRATE ON OXYGEN CONSUMPTION AND CELL DIVISION IN THE EGG OF THE SEA URCHIN, ARBACIA PUNCTULATA
Authors: Fisher Kenneth C. , Henry R. J. 
Published: May 2004

The effects of a series of concentrations of the narcotics, ethyl carbamate and chloral hydrate, have been determined on the consumption of oxygen by fertilized and unfertilized eggs of the sea urchin Arbacia punctulata. In the fertilized eggs the effects of the two inhibitors on cell division were also examined. The following observations were made:
1. Assuming that the narcotic acts upon a single catalyst in the unfertilized egg the degree to which the consumption of oxygen is inhibited in this resting cell can be related to the narcotic concentration by an expression derived from the law of mass action.
2. To account for the relation between the concentration of the narcotic and its effect on respiration in the fertilized eggs, it is necessary to conclude that in them the narcotic acts on two parallel respiratory systems. The experimental data can be quantitatively predicted (1) if the reaction of the narcotic on the two systems is governed by the law of mass action and (2) if 40 per cent of the oxygen consumption is mediated by one system, the "activity" system, and the remainder by the other, the "resting" or "basal" system.
3. The mass law constants applying to the resting system in the fertilized egg are similar to those for the single system functioning in the unfertilized egg so that these two respiratory systems are probably identical.
4. The concentrations of the narcotics just sufficient to abolish cell division affect primarily the activity system, the existence of which was inferred from the respiratory experiments. It is concluded that normal cell division requires specifically the normal function of the activity system, that in fact the energy for cell division is made available through that system.
DIFFERING RATES OF DEATH AT INNER AND OUTER SURFACES OF THE PROTOPLASM
Authors: Osterhout W. J. V. 
Published: May 2004

A previous paper showed that when the inner protoplasmic surface has lost its potential under the influence of formaldehyde the outer surface can still respond to changes in the concentration of electrolytes.
The present paper indicates that after the inner surface has lost its potential there may be a sudden development of negative potential at the outer surface due to substances coming out of the sap and combining with formaldehyde.
NATURE OF THE GROWTH FACTOR FOR THE COLORLESS ALGA PROTOTHECA ZOPFII
Authors: Anderson Edward H. 
Published: May 2004

Barker's study on the nutritive requirements of Prototheca zopfii indicated that this colorless alga fails to grow in the absence of small amounts of yeast extract. A study of the growth factor requirements of Prototheca has shown that the active constituent of yeast extract necessary for the growth of this organism is thiamin (vitamin B1). Thiamin can fully replace the complex yeast material and allows, in the basal medium used, a maximum cell yield in concentrations of 1–3 x 10–7 M.
Thiamin as such, however, is not essential for the growth of Prototheca zopfii. The alga can develop equally well if supplied with both the thiazole and pyrimidine constituents of this vitamin. These appear to be needed in equimolar proportions. Maximum cell yield is obtained with 3 x 10–8 M concentrations of the two components.
MAXIMA IN RATE-CONCENTRATION CURVES AND THEIR RELATION TO THE STRUCTURAL ASPECTS OF CELLULAR METABOLISM
Authors: Spiegelman S. , Reiner J. M. 
Published: May 2004

1. Reproducible maxima are exhibited in the rate-concentration curves obtained by studying the effects of ethyl- and phenylurethanes on regeneration rates of hydranths in Tubularia.
2. The general problem of maxima in rate-concentration curves is analyzed in terms of reaction kinetics of relatively simple systems.
3. Certain systems were shown to exhibit this phenomenon. A comparison is made of these with similar ones which fail to do so.
4. The possible rôle in this phenomenon of cellular structure and its attendant geometrical constraints is discussed in terms of the above comparison.
EFFECTS OF HYDROXYL ON NEGATIVE AND POSITIVE CELLS OF NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

Remarkable changes are brought about by KOH in transforming negative cells of Nitella (showing dilute solution negative with KOH) to positive cells (showing dilute solution positive with KOH). NaOH is less effective as a transforming agent.
This might be explained on the ground that the protoplasm contains an acid (possibly a fatty acid) which makes the cell negative and which is dissolved out more rapidly by KOH than by NaOH, as happens with the fatty acids in ordinary soaps.
Part of a negative cell can be changed to positive by exposure to KOH while the untreated portion remains negative.
After exposure to KOH the potential the protoplasm has when in contact with NaCl may increase. At the same time there may be an increase in the potassium effect; i.e., in the change of P.D. in a positive direction observed when 0.01 M KCl is replaced by 0.01 M NaCl.
In some cases the order of ionic mobilities is uK &gt; vOH &gt; uNa. This shows that the protoplasmic surface cannot be a pore system: for in such a system all cations must have greater mobilities than all anions or vice versa.
SOME PROPERTIES OF PROTOPLASMIC GELS
Authors: Osterhout W. J. V. 
Published: May 2004

The chloroplast of Spirogyra is a long, spirally coiled ribbon which may contract to form a short, nearly straight rod. This happens under natural conditions and it can also be produced by a variety of inorganic salts and by some organic substances.
It also occurs when the chloroplast is freed by centrifugal force from the clear peripheral protoplasm which is in contact with the cellulose wall. It would therefore seem that the chloroplast may be passively stretched by the action of the clear protoplasm and hence it contracts as soon as it is set free. This contraction happens in dead as well as in living cells.
It would be of much interest to know how the protoplasm brings about the coiling of the chloroplast and how the chloroplast is set free by various reagents. Presumably they must penetrate the living protoplasm to produce the effects described.
In one species partial contraction without detachment from the peripheral protoplasm can be brought about by lead acetate. This is reversible. Lead nitrate does not produce this result.
The attack upon the problem is greatly facilitated by the study of dead cells. Thereby we reduce the number of variables but the chloroplast continues to react to certain chemical and physical agents in much the same manner as in the living cell and the solution surrounding it can be controlled as is not possible in the living cell.
We must await further investigation to learn what plant and animal cells contain gels under tension and what functions they perform.
THE MECHANISM OF THE INHIBITION OF HEMOLYSIS
Authors: Ponder Eric 
Published: May 2004

This paper is concerned with hemolytic systems containing sodium taurocholate, sodium glycocholate, or saponin, and either human red cells or the ghosts (stromata) of human red cells. The lysins are allowed to react with the cells for a short time (1 minute or less), and with the ghosts for a long time (4 hours), and the quantity of lysin remaining in the bulk phase, after the removal of the cells or of the ghosts, is found by (a) colorimetric methods, and (b) methods which measure its hemolytic activity.
In the experiments in which the lysins react with the cells for a time so short that none of them is hemolyzed, it is found: (1) that the suspension medium of a cell suspension contains inhibitory substances which render a small amount of the lysin non-lytic, (2) that on the addition of the lysin to the cell suspension, a further and much larger amount of lysin is rendered non-lytic, and (3) that the quantity of chromogenic material in the bulk phase, after the lysin has been in contact with the cells and the latter have been removed, is substantially the same as that initially present. No appreciable quantity of lysin, accordingly, accumulates in increased concentration at the cell surfaces. The results of the colorimetric determinations show that the apparent disappearance of lysin from the bulk phase, once thought to be due to an accumulation of lysin at the cell surfaces, is the result either of an inhibitory process or of a sudden utilization of lysin unrecognized by existing theory.
In the experiments in which the lysins react with stromata for 4 hours, it is found: (1) that the suspension medium of a stroma suspension contains inhibitory substances which render some of the lysin non-lytic, (2) that when the lysin reacts with the stromata over a period of time, a much greater quantity of lysin is rendered non-lytic, and (3) that the concentration of chromogenic material in the bulk phase of the lysin-stroma system, after 4 hours of reaction, is substantially the same as it was initially. The observations can be accounted for by supposing that the lysin molecules are as chromogenic after reacting with the cell components as before, and by their not being bound to the cell or to the ghost, but diffusing back, combined with the components with which they have reacted, into the bulk phase. Such a process would have similarities to the process of penetration and breakdown of mixed protein-lipoid films. Because it is not possible at present to decide how much of the lysin is rendered inert because of utilization in a reaction with cell components, and how much because of the effect of inhibitory substances, difficulties and uncertainties arise in connection with the expressions which have been used to describe the kinetics of hemolysis.