bluuebunny/crossref_metadata_2025_split huggingface dataset:
DARK ADAPTATION AND THE LIGHT-GROWTH RESPONSE OF PHYCOMYCES
Authors: Castle E. S. 
Published: May 2004

1. A single-celled, elongating sporangiophore of Phycomyces responds to a sufficient increase in intensity of illumination by a brief increase in growth rate. This is the "light-growth response" of Blaauw.
2. The reaction time is compound, consisting of an exposure period and a latent period (this comprising both the true latent period resulting from photochemical action and any "action time" necessary for the response). During the latter period the plant may be in darkness, responding nevertheless at the end of the latent period.
3. Both light adaptation and dark adaptation occur in the sporangiophore. The kinetics of dark adaptation can be accounted for on the basis of a bimolecular reaction, perhaps modified by autocatalysis. Attention is called to the bimolecular nature of the "dark" reaction in all other photosensory systems that have been studied, in spite of the diversity of the photosensitive substances themselves and of the different forms of the responses to light.
THE PENETRATION OF STRONG ELECTROLYTES
Authors: Cooper W. C. , Dorcas M. J. , Osterhout W. J. V. 
Published: May 2004

The entrance of strong electrolytes into Valonia is very slow unless the cells are injured. This, together with the very high electrical resistance of the protoplasm, suggests that they may penetrate largely as undissociated molecules formed at the surface of the protoplasm by the collision of ions.
Under favorable circumstances KCl may be absorbed to the extent of 3 x 10–8 mols per hour per sq. cm. of surface together with about 0.17 as much NaCl. Other substances which seem to penetrate to some extent are Li, Rb, Br, BrO3, I, IO3, and selenite.
Little or no penetration is shown by SCN, ferricyanide, ferrocyanide, formate, salicylate, tungstate, seleniate, NO2, SO3, Sb, glycerophosphate, and many heavy metals and the alkaline earths.
In sea water whose specific gravity had been increased by CsCl cells of Valonia floated for over a year and there was little or no penetration of Cs except as the result of injury.
The penetration of NH4Cl decreases the specific gravity of the sap and causes the cells to float: under these circumstances they live indefinitely. It is probable that NH3 or NH4OH penetrates and is subsequently changed to NH4Cl. It would seem that if the sea contained a little more ammonia this would be a floating organism.
THE PERMEABILITY OF DRY COLLODION MEMBRANES. II
Authors: Northrop John H. 
Published: May 2004

The rate of penetration and the solubility of H, O, N, NH3, H2O, HCl gas, CO2, formic, acetic, chloracetic, dichloracetic acid, glycerol, phenol and mercury bichloride in dry collodion membranes have been measured.
The rate of penetration of H and CO2 is the same whether the membrane and gas are dry or whether the membrane is immersed in water.
The solubility of CO2, acetic acid, phenol and water in collodion is completely reversible and is proportional to the concentration (or vapor pressure) in low concentrations and independent of the surface of the collodion.
The size of the pores has been calculated from the vapor pressure of water in the collodion and from the rate of flow of water through the membrane. The results do not agree and are not consistent with the observed rates of penetration.
The relative rates of penetration of the gases bear no relation to the density of the gas.
When the results are corrected for the solubility of the substances in the collodion and expressed as the diffusion coefficient in collodion they show that the diffusion coefficient increases rapidly as the molecular weight decreases.
STUDIES ON PERMEABILITY OF MEMBRANES
Authors: Green Arda A. , Weech A. A. , Michaelis L. 
Published: May 2004

Two methods of measuring the electrical conductivity of the dried collodion membrane in contact with an electrolyte solution are described and the results of such measurements with different electrolytes in different ranges of concentration recorded. Some of the difficulties encountered in making these measurements are outlined. Of special interest was the fact that each membrane with each electrolyte showed a maximum level of resistance at a certain point in the dilution scale, a level which was not surpassed by further dilution. It is believed that this level was fixed by the collodion itself rather than by the contiguous electrolyte solution. Its existence limited the results available for reasonable interpretation. In relatively concentrated solutions the conductivity was shown to be approximately proportional to the concentration. With different electrolytes in the same concentration it was shown that the conductivities varied much more than in simple solutions without a membrane and that they fell in the order HCl &gt; KCl &gt; NaCl &gt; LiCl.
A method was described whereby the electrolyte content of a membrane in contact with different chloride solutions could be determined. It was shown that a membrane saturated with either 0.5 N HCl or 0.5 N KCl had practically the same total electrolyte content whereas the same membrane in contact with 0.5 N LiCl contained only half the quantity. These results were used in interpreting the conductivity data, the evidence presented strongly suggesting that two factors are operative in causing the widely divergent conductivities recorded with different electrolytes. The first factor depended on the quantity of electrolyte which can enter the membrane pores, a quantity dependent on the size of the pores and the volume of the larger of the two hydrated ions of the electrolyte. This factor was the chief one in determining the difference in conductivity between KCl and LiCl. The second factor was concerned with differences in the mobility of the various cations within the membrane brought about by friction between the moving ions and the pore walls. With KCl and HCl the quantity of electrolytes entering the membrane was in each case the same, being determined by the size of the larger Cl- ion. The widely different conductivity values were explained as due to the changes in the mobility of the two cations within the membrane pores.
STUDIES ON PERMEABILITY OF MEMBRANES
Authors: Weech A. A. , Michaelis L. 
Published: May 2004

A study of the behavior of the dried collodion membrane toward the bivalent calcium ion showed that:
1. There is almost no potential difference established across a membrane separating two calcium chloride solutions of 0.1 and 0.01 N concentrations.
2. The transfer numbers of chlorine and calcium, as measured in electrical transfer experiments, are both close to 0.5.
3. A sample of membrane in equilibrium with a solution of calcium chloride has an extremely high electrical resistance, greater than is observed with solutions of the chlorides of any of the monovalent cations.
4. The total electrolyte content of a membrane in equilibrium with a solution of calcium chloride was only 20 per cent of that observed when the solution was lithium chloride and 10 per cent of that found when the solution was potassium chloride.
In explaining these various results it is supposed that (1), (2) and (3) are all the result of (4), that is, of the inability of the calcium ion to penetrate any but the largest of the membrane pores. As the total quantity of electrolyte able to penetrate the membrane is very small the electrical conductivity must also be very small. Moreover, the few larger pores that are large enough to transport the hydrated calcium ion are too large to exert any appreciable effect in decreasing the mobility of the anion. Thus the membrane has no effect in modifying the potentials established across concentration chains with CaCl2 and the transfer numbers determined experimentally are what one would expect if no membrane were present.
THE CATAPHORETIC VELOCITY OF MAMMALIAN RED BLOOD CELLS
Authors: Abramson Harold A. 
Published: May 2004

1. No significant change with time (to 24 hours) in the cataphoretic velocity of certain mammalian red cells occurs when the cells are suspended in M/15 phosphate buffer at pH = 7.35. Neither successive washings nor standing effect a change.
2. In M/15 phosphate buffer at pH 7.35 ± 0.03 the following order of red cell velocity has been obtained. The numbers in parenthesis are µ per second per volt per centimeter.
See PDF for Structure
The order, though not the absolute values, was the same in buffered isotonic dextrose. Human and rabbit cells showed similar differences when both were studied simultaneously in the serum of either. Under these conditions, there is no apparent relationship between zoological Order and cataphoretic velocity.
3. Cholesterol and quartz adsorb gelatin from dilute solution in the phosphate buffer. Red cells, on the other hand, even after 24 hours contact with gelatin solution, retain their previous velocity.
4. Pregnant and non-pregnant white female humans have the same red cell cataphoretic velocity. (The cells were not agglutinated.)
5. In a series of severe anemias no significant change in cataphoretic velocity was in general apparent, although marked changes in the morphology of the red cells were present.
THE CONCENTRATION EFFECT IN NITELLA
Authors: Osterhout W. J. V. , Harris E. S. 
Published: May 2004

A method distinguishing between the concentration effect due to the cell wall and that due to the protoplasm is described: the importance of this lies in the fact that if the protoplasm shows a concentration effect one or both ions of the salt must tend to enter its outer surface.
Studies on the concentration effect of KCl with living protoplasm of Nitella show that when P.D. is plotted as ordinates and the logarithm of concentration as abscissæ the graph is not the straight line demanded in the ideal case by theory but has less slope and is somewhat concave to the axis of the abscissæ.
With a variety of salts the dilute solution is positive, which indicates that the cation has a greater mobility in the protoplasm than the anion or that the partition coefficient of the cation (Ac) increases faster than that of the anion (Aa) as the concentration increases. If the result depended on the partition coefficients we should say that when Ac ÷ Aa increases with concentration the dilute solution is positive. When Ac ÷ Aa decreases as the concentration increases the dilute solution is negative. In either case the increase in concentration may be accompanied by an increase or by a decrease in the relative amount of salt taken up. Theoretically therefore there need be no relation between the sign of the dilute solution and the relative amount of salt taken up with increasing concentration.
Hypothetical diagrams of the electrical conditions in the cell are given.
If we define the chemical effect as the P.D. observed in leading off at two points with equivalent concentrations of different salts we may say that the chemical effect of the protoplasm is very much greater than that of the cell wall.
A PRELIMINARY STUDY OF THE REDUCING INTENSITY OF LUMINOUS BACTERIA
Authors: Harvey E. Newton 
Published: May 2004

The effect of a series of redox indicators and systems has been tested with a suspension of luminous bacteria (B. fischeri) in M/4 phosphate buffer of PH = 7.6.
The indicators behave as expected from their position in the redox series, the most positive being reduced rapidly even in presence of air and before luminescence of the bacteria disappears, those of intermediate position at the time luminescence disappears, and the more negative only long after the luminescence had ceased, due to utilization of oxygen by the bacterial respiration. Indigo monosulphonate was the only indicator not reduced on long standing of a bacterial suspension. The aerobic redox potential may be placed at an RH = 18–20 and the anaerobic potential at an RH = 8–10.
Ferricyanides do not affect luminescence and behave as if they could not penetrate the bacterial cell. Quinone and the napthoquinones cause progressive dimming of luminescence in any concentration which affects the light but it cannot be definitely stated that this is due to rapid oxidation of luciferin although it seems likely in the case of quinone. Some indophenols dim the luminescence at first, followed by return of brightness, which is interpreted to mean rapid oxidation of luciferin while the indophenol is unreduced, more luciferin production after reduction of indophenol. The more negative redox systems do not affect the luminescence. Investigation of indicator reduction and luminescence is being continued.
MEASUREMENTS OF THE METABOLISM OF TWO PROTOZOANS
Authors: Emerson Robert 
Published: May 2004

1. The respiration of Amoeba proteus was measured. 10 c. mm. of cells were found to use about 1.6 mm.3 of oxygen per hour at 20°C. The respiratory quotient was found to be nearly unity.
2. No anaerobic metabolism was found for Amoeba.
3. The respiration of Blepharisma was found to be from 3 to 7 mm.3 oxygen per hour for 10 mm.3 cells. The respiratory quotient was about 1.
4. Blepharisma was shown to have a definite anaerobic metabolism. 80 mm.3 cells caused the evolution of 12.5 mm.3 carbon dioxide per hour at 20°C. in the presence of bicarbonate.
ELECTROKINETIC PHENOMENA
Authors: Abramson Harold A. 
Published: May 2004

1. The effect of human and rabbit sera on the cataphoretic mobility of glass and quartz particles, and of paraffin oil droplets, was studied in serum dilutions (with 0.85 per cent NaCl) from 1:50 to 1:1,000,000, over a pH range of 3.6 to 9.3.
2. Under the conditions described, these various types of particles adsorbed protein partially or completely from the most dilute solution giving these particles electrokinetic properties characteristic of certain proteins, probably here those of serum albumin.
3. Quartz particles and paraffin oil droplets both have an isoelectric point between 4.7 and 4.8 in a 1:50 serum dilution.
4. The biological importance of these findings is discussed.
5. A non-polarizable electrode composed of
See PDF for Structure
is described for use with cataphoresis cells.
A STUDY OF THE BACTERICIDAL ACTION OF ULTRA VIOLET LIGHT
Authors: Gates Frederick L. 
Published: May 2004

1. Wide differences in the intensity of incident ultra violet energy are not accurately compensated by corresponding changes in the exposure time, so that the Bunsen-Roscoe reciprocity law does not hold, strictly, especially for bactericidal action on young, metabolically and genetically active bacteria. In the present series of experiments, however, the energies used at various wave lengths did not differ by so much as to cause a significant error in the reported reactions.
2. The longer wave length limit of a direct bactericidal action on S. aureus was found to be between 302 and 313 mµ. The shorter limit was not determined because the long exposures required vitiate quantitative results. Bactericidal action was observed at λ225 mµ.
3. The temperature coefficient of the bactericidal reaction approaches 1 and thus furnishes empirical evidence that the direct action of ultra violet light on bacteria is essentially physical or photochemical in character.
4. The hydrogen ion concentration of the environment has no appreciable effect upon the bactericidal reaction between the limits of pH 4.5 and 7.5. At pH 9 and 10 evidence of a slight but definite increase in bacterial susceptibility was noted, but this difference may have been due to a less favorable environment for subsequent recovery and multiplication of injured organisms.
5. Plane polarization of incident ultra violet radiation has no demonstrable effect upon its bactericidal action.
In a third paper of this group the ratios of incident to absorbed ultra violet energy at various wave lengths and the significance of these relations in an analysis of the bactericidal reaction will be discussed.
THE SUBSTRATE IN PEPTIC SYNTHESIS OF PROTEIN
Authors: Borsook Henry , MacFadyen Douglas A. , Wasteneys Hardolph 
Published: May 2004

1. Experiments are described in which it was observed that the yield of protein that can be synthesized by pepsin from a given peptic digest is highest when the hydrolyzing action of the pepsin is stopped as soon as all the protein has disappeared from the solution; and that the longer the digest is permitted to contain active enzyme the more the yield diminishes.
2. Exposure of the digest to a hydrogen ion concentration of pH 1.6 in the absence of active enzyme, does not cause a diminution in the amount of protein which can be synthesized from that digest.
3. Synthesis can be effected also in concentrated solutions of isolated fractions of a peptic digest, i.e. of proteose and of peptone. The yields are approximately the same as in similar concentrations of the whole digest, though the proteins so synthesized differ in some respects from those obtained from the whole digest.
4. The cessation of synthesis in any one digest is due to the attainment of equilibrium and not to the complete utilization of available synthesizeable material. The amount of the equilibrium yield, on the other hand, is dependent on the amount of synthesizeable material in the digest.
5. These observations are taken to show that the synthesizeability of a given mixture of protein cleavage products by pepsin depends upon its possession of a special complex in these products. This complex appears as a result of the primary hydrolysis of the protein molecule by pepsin and is decomposed in the slow secondary hydrolysis which ensues as digestion is prolonged.
A CRYSTALLOGRAPHIC STUDY OF PURE CARBONMON-OXIDE HEMOGLOBIN
Authors: Boor Alden Kinney 
Published: May 2004

1. Photomicrographs of crystals of pure carbonmonoxide hemoglobin of the following species are presented; ox, sheep, hog, dog, turkey, rat, horse, chicken and guinea pig. Photomicrographs of the oxyhemoglobin crystals of the following species are also shown: ox, sheep, hog, dog, rat, horse and guinea pig. The crystals were formed from the pure protein by adding a suitable amount of ethyl alcohol and maintaining a temperature of 0°C., or lower.
2. In some species a sufficient difference is shown between the carbonmonoxide hemoglobin and oxyhemoglobin crystals to distinguish these compounds, but the photographs of crystals of carbonmonoxide hemoglobin and oxyhemoglobin of some species, such as guinea pig, show no appreciable difference.
3. Differences between the carbonmonoxide hemoglobins, as well as between the oxyhemoglobins, of the different species studied are indicated.
4. The carbonmonoxide hemoglobin crystals from the bloods studied are species specific in their nature, and, in many cases, can be distinguished from the analogous oxyhemoglobin by crystallographic study.
THE KINETICS OF ENZYME REACTIONS: SCHÜTZ'S LAW
Authors: Moelwyn-Hughes E. A. , Pace J. , Lewis W. C. M. 
Published: May 2004

1. A review of the applicability of Schütz's Law to enzymic reactions is given.
2. The theoretical deductions of the Law, (a) on the basis of the law of mass action, (b) on the basis of the adsorption theory, are given and the significance of the assumptions made in these deductions pointed out.
3. It is shown that the true critical increment for an enzymic reaction is equal to twice the critical increment calculated from the Schütz constant ks, if the heat of decomposition of the enzyme-products complex be neglected.
4. Experiments are described on the tryptic hydrolysis of casein at 30°C. and 404C. The foregoing considerations are applied to the experimental results obtained.
THE NON-LOGARITHMIC ORDER OF DEATH OF SOME BACTERIA
Authors: Rahn Otto 
Published: May 2004

In a previous paper, it has been shown that the logarithmic order of death of bacteria can be accounted for by the assumption that each cell contains one or several extremely sensitive molecules and that the destruction or inactivation of any one of these prevents multiplication of the cell.
In this paper, the apparent exceptions to the logarithmic order are dealt with. It has been shown that the decreasing death rate can well be accounted for by the assumption of a variation in resistance of the cells under test.
The few cases of increasing death rates might be indicative of a different cell structure, requiring the destruction of 2 or 3 molecules before multiplication is made impossible. More probable, however, is the assumption that these bacteria behave exactly like the others, and that the apparently larger number of molecules per cell is caused by our imperfect method of counting living bacteria by the plating method where a cluster of several cells can be counted only as one cell. Bacteria with a tendency for clustering are likely to give results resembling the expectation for several reacting molecules per cell.
PHOTOTROPISM AND THE LIGHT-SENSITIVE SYSTEM OF PHYCOMYCES
Authors: Castle E. S. 
Published: May 2004

1. The reaction time of the direct growth response of the sporangiophore of Phycomyces to light consists of a series of at least three major identifiable components: (a) an exposure period during which photochemical change occurs; (b) a latent period involving products directly consequent upon the photochemical action; and (c) an action-time occupying a further interval before the growth acceleration appears.
2. The reaction time of the phototropic response of the sporangiophore following stimulation by unilateral illumination is also compound, and is made up of at least three components comparable to those of the direct growth response.
3. The reaction time of each mode of response is constant for a particular intensity of illumination, provided that the duration of the exposure period exceeds a certain value. Below that value the reaction time increases progressively as the exposure time decreases.
4. The reaction time of each mode of response is found to vary similarly as a function of the duration of exposure to light. It is therefore concluded that the two responses are based on the same light-sensitive system. This conclusion accords with the conception of plant phototropism developed by Blaauw.
5. If a constant representing the action-time is subtracted from the reaction times for either mode of response, the reciprocals of the resulting numbers follow a linear sequence when plotted against the durations of the exposure to light. The rate of the process occurring during the latent period is therefore considered to be directly proportional to the amount of preceding photochemical change.
THE CONCENTRATION EFFECT WITH VALONIA: POTENTIAL DIFFERENCES WITH CONCENTRATED AND DILUTED SEA WATER
Authors: Damon E. B. , Osterhout W. J. V. 
Published: May 2004

The P.D. between the interior of a cell of Valonia macrophysa and concentrated or diluted sea water applied externally is given by the empirical equation:
See PDF for Equation
where P.D.s.w. is the value observed when the external solution is sea water. The sign is that of the interior of the cell. In the chain:
sea water, concn.1 | Valonia | sea water, concn.2
therefore, the more concentrated solution is positive in the external circuit to the more dilute solution.
This holds for the concentration range 1.5 sea water to 0.2 sea water, when the dilute solutions are made isotonic with sea water by the addition of a suitable non-electrolyte (such as glycerol). Prolonged exposure to these solutions, or brief exposure to very concentrated or very dilute sea water, or to hypotonic solutions, produces in the cell secondary changes which are made evident by the reversal of the sign of the P.D. These changes are to a certain extent reversible, but if allowed to proceed too far they become irreversible, involving permanent injury to the cell.
The concentration effect with sea water is shown to be practically the concentration effect for NaCl, the part played by the other salts in sea water being relatively small.