bluuebunny/crossref_metadata_2025_split huggingface dataset:
REVIVAL OF MAMMALIAN SPERM AFTER IMMERSION IN LIQUID NITROGEN
Authors: Hoagland Hudson , Pincus Gregory 
Published: May 2004

1. A wide variety of procedures was used to test the motility of mammalian sperm after plunging them into liquid nitrogen at –195°C. and later rapidly warming them to 35°C. by plunging them into a suitable balanced and isotonic medium.
2. Using seminal fluid sperm from the same human donor, maximal numbers of motile sperm survived vitrification when the samples were (a) very fresh, (b) untreated with plasmolysing solutions, (c) plunged into the refrigerant in the form of a foam. The maximum yield of motile human sperm recoverable from the liquid nitrogen was 50 per cent. Since in this sample only 75 per cent of the sperm were alive before immersion, 67 per cent of the living sperm survived vitrification.
3. Experiments with sperm from 31 rabbits were made with a variety of conditions of pretreatment to obtain maximal yields of recoverable, motile sperm after vitrification by liquid nitrogen. (a) A consistent recoverable yield of about 0.5 per cent was obtained when the untreated suspension of sperm was smeared on cellophane and partially dried in air before immersing in liquid nitrogen. (b) On a few out of many occasions plasmolysis for several minutes with hypertonic Ringer solution gave a recoverable yield of 0.1 per cent as did (c) pretreatment with hypertonic Ringer and butyric acid.
THE ACTION OF SULFONAMIDES ON THE RESPIRATION OF BACTERIA AND YEAST
Authors: Sevag M. G. , Shelburne M. , Mudd Stuart 
Published: May 2004

The inhibiting effects of sulfonamide drugs and their derivatives on the anaerobic decarboxylation of pyruvic acid by Staphylococcus aureus, Escherichia coli, baker's and brewer's yeast, and a carboxylase preparation from brewer's yeast have been investigated. These drugs are: sulfanilamide, sulfapyridine, sulfadiazine, sulfamethyldiazine, sulfathiazole, sulfamethylthiazole, sulfanilamido-5-ethyl-4-thiazolone, 2-aminopyrimidine, 2-aminothiazole, and 2-aminopyridine.
The sulfathiazole ring appears to exercise decidedly greater specific inhibiting effect on the carboxylases of Staph. aureus and E. coli. The inhibiting effect on yeast carboxylase is non-differentiable among all the substances tried, except sulfamethyldiazine which is completely ineffective on the carboxylases of the organisms studied.
The specific inhibitory effect of sulfathiazole on the carboxylases of Staph. aureus and E. coli in comparison to sulfanilamide, sulfapyridine, and sulfadiazine is in harmony with in vivo and in vitro experimental results of other investigators.
The results of the present investigation appear to support the hypothesis (1) that sulfonamides exert their bacteriostatic action through chemical affinity for the carrier proteins of certain respiratory enzymes of the bacterial cell, and that this affinity may in part be related to structural similarity between components of the drugs and the corresponding respiratory coenzymes.
CYANIDE-SENSITIVE BACTERIAL RESPIRATORY SYSTEMS DIFFERENT FROM THE USUAL CYTOCHROME-CYTOCHROME OXIDASE SYSTEM
Authors: Sevag M. G. , Shelburne M. 
Published: May 2004

Aerobic respiration of Streptococcus pyogenes and pneumococcus Type 1 are strongly inhibited by KCN, NaN3, and Na2S. The anaerobic glycolysis of glucose by pneumococcus is also inhibited by KCN and NaN3.
Streptococcus pyogenes, E. coli, pneumococcus Type 1, B. subtilis, B. proteus, and Staphylococcus aureus did not catalyze the oxygen uptake by p-phenylenediamine in the presence of added cytochrome c or in its absence. Yeast cells, B. subtilis, and B. pyocyaneus oxidized p-phenylenediamine to a dark purple meriquinoid substance in contrast to the other bacteria mentioned above.
Streptococcus pyogenes in contrast to pneumococcus Type 1 catalyzed the oxygen uptake by cysteine. Neither of these bacteria catalyzed the oxygen uptake by tyrosine, adrenaline, pyrocatechin, xanthine, and hypoxanthine.
Streptococcus pyogenes, pneumococcus Type 1, and E. coli, boiled and not boiled, gave positive peroxidative tests with benzidine showing the presence of hematin compounds.
The results discussed in the light of the interpretations offered by Keilin and Harpley show that Streptococcus pyogenes and pneumococcus Type 1 contain cyanide-sensitive respiratory systems which are different from the cytochrome c-cytochrome oxidase system.
ON THE CALCULATION OF "TURNOVER TIME" AND "TURNOVER RATE" FROM EXPERIMENTS INVOLVING THE USE OF LABELING AGENTS
Authors: Zilversmit D. B. , Entenman C. , Fishler M. C. 
Published: May 2004

1. A new method for the determination of an immediate precursor of a substance occurring in the animal body is presented.
2. Calculations on the quantitative determination of the rate of turnover of a substance and their application to experiments involving the use of labeling agents are given. These calculations take into account loss of the isotopic substance by way of breakdown or transport.
THE EFFECT OF TEMPERATURE ON THE RATE OF HYDROLYSIS OF TRIGLYCERIDES BY PANCREATIC LIPASE
Authors: Schwartz Boris 
Published: May 2004

1. The temperature characteristics for the hydrolysis of various concentrations of tributyrin, trivalerin, tricaproin, triheptylin, and tricaprylin have been determined.
2. The µ values for the hydrolysis of all concentrations of tributyrin by pancreatic lipase, except the most dilute, were found to be constant within the experimental error, 8,500 ± 1,000.
3. The temperature characteristics for the hydrolysis of trivalerin, tricaproin, triheptylin, and tricaprylin varied from approximately 8,500 ± 1,000 for the high concentrations to 12,400, 20,000, 22,400, and 23,700 respectively for the most dilute concentration of each.
4. An interpretation of these results was presented.
THE QUANTUM YIELD OF OXYGEN PRODUCTION BY CHLOROPLASTS SUSPENDED IN SOLUTIONS CONTAINING FERRIC OXALATE
Authors: French C. S. , Rabideau G. S. 
Published: May 2004

1. The quantum yield of oxygen liberation by spinach and Tradescantia chloroplasts suspended in solutions containing ferric oxalate and potassium ferricyanide varied from 0.013 to 0.080.
2. It was concluded that the nature of this oxygen liberation reaction is not fundamentally different from the formation of oxygen in normal photosynthesis, with respect to its light efficiency.
METABOLISM OF TISSUE CULTURES
Authors: Cohn Waldo E. , Brues Austin M. 
Published: May 2004

By using radioactive isotopes in tissue cultures, the rate of permeation of substances into cells can be measured independently of concurrent metabolic reactions of these substances. Techniques of obtaining and analyzing data are described. Examples are given using radioactive potassium and phosphorus.
Using cultures of chick embryo muscle, turnover time for cell potassium is 6 hours, and for cell inorganic phosphate is 7 hours in the examples cited. Permeability rates, based on estimates of the cell surface involved and expressed as millimoles per cm.2 per hour, are of the order of magnitude of 10–6 for potassium and of 10–7 for phosphate.
THE TEMPERATURE COEFFICIENT OF THE UREA DENATURATION OF EGG ALBUMIN
Authors: Clark Janet Howell 
Published: May 2004

Evidence is brought forward to show that at concentrations of urea high enough to split the egg albumin molecule the solubility changes produced by urea are profoundly modified. The degree of precipitation after dialysis is the net result of two changes produced by the urea: the first, normally spoken of as denaturation, which makes the protein insoluble in dilute solution and the second, a splitting of the molecule which makes it soluble. These two reactions may proceed independently and simultaneously or the second reaction may follow the first, taking place in the denatured molecule only. In view of the decrease in the opalescence with time, the latter process is more probable.
Both of these reactions have positive temperature coefficients, but as the concentration of urea increases the second reaction is more affected by increase in temperature than the first, and consequently the resulting opalescence decreases rather than increases with temperature. This accounts for and explains reports of negative temperature coefficients of denaturation, when denaturation is measured by the amount of insoluble material found on dilution.
The occurrence of these two reactions, one leading to an increase and the other to a decrease in the amount of insoluble protein, should be taken into account when denaturation changes in egg albumin with urea are studied.
THE EFFECTS OF OXYGEN, CARBON DIOXIDE, AND PRESSURE ON GROWTH IN CHILOMONAS PARAMECIUM AND TETRAHYMENA GELEII FURGASON
Authors: Pace D. M. , Ireland R. L. 
Published: May 2004

1. The effects of O2, CO2, and pressure were studied in two very different species of protozoa, a flagellate, Chilomonas paramecium, grown in acetate-ammonium solution and a ciliate, Tetrahymena geleii, grown in 2 per cent proteose-peptone solution.
2. Chilomonas and Tetrahymena live and reproduce in solutions exposed to a wide range of O2 concentrations, but Chilomonas is killed at high O2 tensions in which Tetrahymena grows best. The optimum O2 concentration for Chilomonas is about 75 mm. pressure but it lives and reproduces in O2 tensions as low as 0.5 mm. while Tetrahymena fails to grow in concentrations below 10 mm. O2 pressure.
3. With a constant O2 tension of 50 mm. pressure, it was found that there is no significant variation in growth in Chilomonas between 50 mm. and 740 mm. total pressure. In Tetrahymena, however, under the same conditions, an optimum total pressure was found at about 500 mm. and growth is comparatively poor at 50 mm. total pressure.
4. Tetrahymena does not live very long in CO2 tensions over 122 mm., although Chilomonas grows as well at 400 mm. CO2 as in air at atmospheric pressure (0.2 mm. CO2). Tetrahymena grows best in an environment minus CO2, but the optimum for Chilomonas is 100 mm. CO2 at which pressure an average of 668,600 ± 30,000 organisms per ml. was produced (temperature, 25 ± 1° C.).
5. Chilomonads grown in high CO2 concentrations (e.g., 122 mm.) produce larger starch granules and more starch than those grown in ordinary air at atmospheric pressure.
6. In solutions exposed to 75 mm. O2 tension (optimum) and 122 mm. CO2 plus 540 mm. N2 pressure, chilomonads contain very little, if any, fat. This phenomenon seems to be due to the action of CO2 on the mechanisms concerned with fat production.
7. In Tetrahymena exposed to pure O2, there is very little fat compared to those grown in atmospheric air. This may be due to the greater oxidation of fat in the higher O2 concentrations.
8. Further evidence is presented in support of the contention that Chilomonas utilizes CO2 in the production of starch.
ON THE NATURE OF FORCES OPERATING IN BLOOD CLOTTING
Authors: Mommaerts W. F. H. M. 
Published: May 2004

The results of the study of the inhibiting effect of neutral salts upon the clotting tendency of fibrinogen by thrombin may be summarised as follows:
Salts like NaCl and KCl inhibit only weakly.
Salts of the same cation (K•) with monovalent anions of different ionic radius are the more active the larger the anion (Cl',Br',I').
Salts of the same cation with anions of different valency are the more active the higher the charge of the anion (1–1 &lt;1–2 &lt;1–3 &lt;1–4).
Salts with the same anion with cations of different valency show stronger inhibition in the case of cations of higher charge (K•,Na• &lt; Mg••, Ca••, Sr••, Ba••).
Salts with the same anion and cations of the same charge, but of different radius, are the more active the larger the cation (but with an inversion between Mg•• and Ca•• in the series of the alkali earths, which is not infrequent in biocolloids).
These results show that the clotting of fibrinogen with thrombin is, at least partly, caused by a coacervation process, due to electrostatic attraction between positive and negative groups. Its nature and localisation will be dealt with in the next paper of this series.
ON THE NATURE OF FORCES OPERATING IN BLOOD CLOTTING
Authors: Mommaerts W. F. H. M. 
Published: May 2004

It is found that clotting of fibrinogen by thrombin does not occur on the acid side of the isoelectric point of the fibrinogen. At such pH values, however, a primary reaction between thrombin and fibrinogen takes place, leading to the formation of profibrin, a compound of thrombin and fibrinogen.
At pH values at which clotting is possible, fibrinogen is negatively, thrombin positively charged, whereas profibrin has a pattern of positive and negative charges.
The primary reaction, the formation of profibrin by combination of thrombin and fibrinogen, is inhibited by urea but not by neutral salts. The combination of thrombin with fibrinogen most probably takes place by hydrogen bonds.
The second reaction, the polymerisation of profibrin to fibrin, is inhibited by neutral salts in the same way as complex or autocomplex coacervates. It is caused therefore by electrostatic attraction between the positive and the negative charges of the profibrin.
POTASSIUM ACCUMULATION IN THE PROXIMAL CONVOLUTED TUBULES OF THE FROG'S KIDNEY
Authors: Conway E. J. , Fitzgerald O. , Macdougald T. C. 
Published: May 2004

1. In a manner similar to that of the sartorius muscle, the isolated kidney of the frog can accumulate K against a gradient to upwards of three times its normal concentration.
2. The K-accumulating region is identified as the proximal tubule, which in the isolated tissue immersed over 24 hours in the cold (2–3°C.) amounts to about 90 per cent of the nephron minus the glomerulus. In the fresh tissue it constitutes about 70 per cent.
The cells of the proximal tubule are impermeable to Na, but freely permeable to K and Cl.
3. The distal tubule in the isolated kidney does not accumulate K over the external concentration. The cells are permeable to Na which they actively extrude. This extrusion of Na goes parallel with a loss of osmotically associated water amounting to about 15 per cent of the weight of the fresh kidney, but varying somewhat with the conditions.
4. The accumulation of K in the proximal tubules is in accordance with the equations established for the sartorius muscle, and, as theoretically expected, there is no volume increase (but rather a small decrease) with the large accumulations, when the external Na concentration is maintained throughout.
5. With K accumulation in isotonic mixtures large volume changes occur as K is progressively substituted for Na. Over the range of external K concentration of 10 to 100 mM per litre the weight of the whole kidney changes to 2.5 times and the water of the cells of the proximal tubules increases to over four times. Up to an external K value of 90 mM per litre the mean weight of the kidney shows a linear relation when plotted against the reciprocal of the Na concentration plus the small glucose and Ca concentration. This relation is interpreted theoretically.
6. The effect of cyanide in the isotonic mixtures is to prevent the contraction of the distal tubules and to cause swelling of the same. It does not affect the volume, volume changes, or differential permeability of the proximal tubule. At the same time the membranes of the proximal tubule cells lose their characteristic permeability at a lower level of distension in the presence of cyanide.
7. The mean Na ratio for the kidney after 24 hours' immersion in the cold is 0.26 ± 0.014 (giving standard deviation of mean). The ratio is defined as
See PDF for Equation.
For the fresh kidney the mean ratio is 0.39 ± 0.006.
8. The mean inulin ratio (28 observed in the cold) is 0.23 ± 0.012 and the same value for 10 observed at room temperature. At room temperature—2 hour immersion—the ratio is increased by cyanide to a mean of 0.32 ± 0.028, but only a slight increase is caused by cyanide in the cold.
9. The mean hemoglobin ratio after 24 hours' immersion in the cold is 0.17 ± 0.004 and is unaffected by cyanide.
CULTURE CONDITIONS AND THE DEVELOPMENT OF THE PHOTOSYNTHETIC MECHANISM
Authors: Myers Jack ,   With the Technical Assistance of Frank Ervin and Mary Lou Murray
Published: May 2004

1. Chlorella pyrenoidosa has been grown in a continuous-culture apparatus under various light intensities provided by incandescent lamps, other conditions of culture being maintained constant. Light intensity curves for cells immersed in the No. 11 Warburg buffer and in Knop's solution + 4.4 per cent CO2 at a saturating light intensity were determined as characteristics of the photosynthetic mechanism. These characteristics were referred to the centrifuged cell volume as an index of quantity of cellular material.
2. Cells grown at intensities in the range of about 35 f.-c. develop a capacity for a high rate of photosynthesis (c.mm. O2/hour/c.mm. cells). At culture intensities above or below this range the cells produced have a lower capacity for photosynthesis. A similar effect is observed for rate of photosynthesis per unit dry weight or rate per unit cell nitrogen.
3. The rate of photosynthesis per cell or rate per unit chlorophyll shows no maximum at any light intensity of culture but increases continuously throughout the range of light intensities studied.
4. Maximum rate of growth is attained at a light intensity of about 100 f.-c. The hypothesis is advanced that at culture intensities above that needed to give maximum rate of growth (100 f.-c.) a mechanism is developed which opposes the photosynthetic process and removes the photosynthetic products.
5. The low capacity for photosynthesis shown by cells grown at culture intensities below 35 f.-c. finds no immediate explanation.
6. The shape of the light intensity curve is markedly affected by the light intensity at which the cells have been cultured. Cells grown at lower intensities give light intensity curves approaching the Blackman type with a short transitional region between light limitation and light saturation.
DYNAMICS OF NERVE CELLS
Authors: Garrey Walter E. 
Published: May 2004

1. It is possible to determine by the colorimetric method the rate of production of carbon dioxide by the cardiac ganglion of Limulus.
2. Carbon dioxide formation in the cardiac ganglion was found to run parallel to the rate of heart beat for different temperatures.
3. The conclusion seems justified that the rate of cardiac rhythm of Limulus depends upon a chemical reaction in the nerve cells of the cardiac ganglion and that this reaction is associated with the production of carbon dioxide since the rate of beat and the rate of CO2 production are similarly affected by changes in temperature.
THE RECOVERY OF TRANSMISSIVITY IN PASSIVE IRON WIRES AS A MODEL OF RECOVERY PROCESSES IN IRRITABLE LIVING SYSTEMS
Authors: Lillie Ralph S. 
Published: May 2004

1. Passive iron (steel) wires, when activated after prolonged immersion in nitric acid of 55 to 90 per cent concentration (volumes per cent of HNO3, specific gravity 1.42) revert spontaneously to the passive state, after a temporary reaction which is transmitted rapidly over the whole length of wire. The duration of this reaction at any region decreases rapidly with increase in the concentration above a certain critical limit of 52 to 54 per cent. In weaker acid (50 per cent and lower) the reaction continues uninterruptedly until all the metal is dissolved.
2. Immediately after this automatic repassivation the wire fails to transmit activation through more than a short distance (1 to 2 cm.); if left undisturbed in the acid it recovers by degrees its power of transmission (as measured by the distance traveled by an activation wave), at first slowly, then more rapidly; eventually, after an interval varying with the concentration of acid and the temperature, the activation wave is transmitted through an indefinite distance as before.
3. The return of complete transmissivity in 55 per cent acid occupies less than a minute (at 20°); in stronger acid it is more gradual, requiring in 90 per cent acid 20 minutes or more. This "complete recovery time" is nearly proportional to the excess of concentration of acid above the limiting value of 53 to 54 per cent.
4. In a given solution of acid the rate of recovery exhibits a temperature coefficient closely similar to that of most chemical reactions at this temperature (3–20°), and also to that of the rate of recovery (refractory period) of irritable living tissues after stimulation (Q10 = about 3).
5. Two definite phases are distinguishable in the recovery process: (1) the redeposition of the continuous passivating surface layer (of oxide or oxygen compound); and (2) the progressive change of the newly passivated wire from the state of incomplete to that of complete transmissivity. The former phase is of brief duration and is indicated by a sudden change in the electrical potential of the wire, from that of active to that of passive iron; this phase is succeeded by the second and more prolonged period during which the passivating layer undergoes the progressive alteration associated with the recovery of transmissivity. This alteration appears to consist in a progressive thinning of the passivating film until a minimal thickness of (probably 1 molecule) is attained. Further thinning is prevented by local electrochemical oxidation.
6. The phenomena of partial or limited transmission during the second phase of the recovery process show a close correspondence with the phenomena of conduction with decrement in irritable living tissues such as nerve. Other analogies with the behavior of irritable tissues (threshold phenomena, distinction between "local" and "propagated" effects, summation, effects resembling electrotonus) are described.
A THEORY OF INJURY AND RECOVERY
Authors: Osterhout W. J. V. 
Published: May 2004

1. Laminaria exposed for a short period to 0.52 M NaCl loses a part of its electrical resistance but recovers it completely when replaced in sea water. When the period is lengthened recovery is incomplete. If the exposure is sufficiently prolonged no recovery occurs. (After exposure to 0.278 M CaCl2 the resistance falls when the tissue is replaced in sea water.)
2. Equations are developed which enable us to predict the resistance of the tissue during exposure to NaCl or CaCl2 as well as the recovery curves after any length of exposure to either of these solutions.
THE KINETICS OF INACTIVATION OF COMPLEMENT BY LIGHT
Authors: Brooks S. C. 
Published: May 2004

The photoinactivation of complement has been studied with a view to determining if possible how many kinds of molecules disappeared during the reaction. It was found that:
1. The apparent course of photoinactivation is that of a monomolecular reaction.
2. Diffusion is not the limiting factor responsible for this fact, because the temperature coefficient of diffusion is much higher than that of photoinactivation (Q10 = 1.22 to 1.28, and Q10 = 1.10 respectively).
3. There is no change in the transparency of serum solutions during photoinactivation, at least for light of the effective wave-length, which is in the ultra-violet region probably at about 2530 Ångström units.
It is pointed out that under these conditions only one interpretation is possible; namely, that during photoinactivation a single disappearing molecular species governs the rate of reaction. This substance must be primarily responsible for the hemolytic power of serum when it is used as complement.