bluuebunny/crossref_metadata_2025_split huggingface dataset:
FERTILIZATION AND THE TEMPERATURE COEFFICIENTS OF OXYGEN CONSUMPTION IN EGGS OF ARBACIA PUNCTULATA
Authors: Rubenstein B. B. , Gerard R. W. 
Published: May 2004

The eggs of A. punctulata have a high temperature coefficient in the resting state: Q10 = 4.1.
On fertilization and on cytolysis the temperature coefficient falls to less than half the resting value: Q10 = 1.8 and 1.9 respectively.
The factor by which oxygen consumption increases on fertilization is a variable, its magnitude depending on temperature as well as on egg species. It is nearly ten times greater at 11°C. and only double at 29.9°C. By extrapolating to 32°C. there would be no increase on fertilization.
Critical thermal increments common to many oxidations, 6,500, 10,800, and 12,500, have been found.
The possible significance of these results is discussed in relation to the catalytic mechanisms and structural organization of the egg cell.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G. , Osterhout W. J. V. 
Published: May 2004

It would be natural to suppose that potassium enters Valonia as KCl since it appears in this form in the sap. We find, however, that on this basis we cannot predict the behavior of potassium in any respect. But we can readily do so if we assume that it penetrates chiefly as KOH. We may then say that under normal conditions potassium enters the cell because the ionic activity product (K) (OH) is greater outside than inside. This hypothesis.leads to the following predictions:
1. When the product (K) (OH) becomes greater inside (because the inside concentration of OH- rises, or the outside concentration of K+ or of OH- falls) potassium should leave the cell, though sodium continues to enter. Previous experiments, and those in this paper, indicate that this is the case.
2. Increasing the pH value of the sea water should increase the rate of entrance of potassium, and vice versa. This appears to be shown by the results described in the present paper.
It appears that photosynthesis increases the rate of entrance of potassium by increasing the pH value just outside the protoplasm. In darkness there is little or no growth or absorption of electrolytes.
The entrance of potassium by ionic exchange (K+ exchanged for H+ produced in the cell), the ions passing as such through the protoplasmic surface, does not seem to be important.
RESULTS OF IRRADIATING SACCHAROMYCES WITH MONOCHROMATIC ULTRA-VIOLET LIGHT
Authors: Oster Robert H. 
Published: May 2004

Effects of measured ultra-violet light on the yeast S. cerevisiae have been studied. Methods of culturing and irradiating the yeast, of estimating the nature and extent of the changes produced, and the means used in producing and measuring the radiation are given.
No evidence of a stimulative action was observed. The absorbed energy did not produce an all or none effect; arbitrary criteria must be used for judging the various inhibitory and lethal effects. With increase in the incident energy diverse effects were produced until abnormal cell growth and "death" of the cells resulted. Changes in the rate of oxygen consumption did not occur until after a high proportion of the irradiated cells were so damaged that they produced abnormal cells.
The shape of the curves relating effect to energy are similar for various wave-lengths but different energies are required to produce the same effect at each of the wave-lengths studied. The similarity of the curves to that for a first order reaction is noted, but attention is called to the modifying influence of accessory factors such as the age of the cells. A comparison is made of the morphological and metabolic changes on the basis of energy requirements, and their relative value as criteria in judging the effects of ultra-violet light on yeast and physiologically similar microorganisms.
ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. II
Authors: Hoagland Hudson 
Published: May 2004

Studies of axon potentials set up by pressure stimuli applied to single cutaneous receptors in frog's skin indicate that the mechanical stimulus excites the free nerve endings directly.
Adaptation to constant pressures or to intermittently applied pressures (failure of the response) may be due to the reduction of excitability of the nerve endings by potassium released under the pressure from surrounding epithelial cells.
POSITIVE VARIATIONS IN NITELLA
Authors: Osterhout W. J. V. , Hill S. E. 
Published: May 2004

The reversible electrical variations hitherto described for plants and animals consist in a reversible loss of positive potential at a stimulated spot by which it becomes more negative.
In this paper we describe changes which consist in a reversible loss of negative potential at a stimulated spot whereby it becomes more positive. We suggest that this be called a positive variation.
The stimulation was produced in all cases by pinching or bending the cell. This produced a compression wave which traveled along the cell, producing a negative variation at a spot which was positive and a positive variation at a spot which was negative (due to application of 0.1 M KCl).
The response produced by the compression wave differs in several respects from an ordinary propagated negative variation and may be termed a positive mechanical variation.
PROTOPLASMIC POTENTIALS IN HALICYSTIS
Authors: Blinks L. R. 
Published: May 2004

Perfusion of the vacuole of living cells of Halicystis is described, the method employing two longitudinally fused capillaries as entrance and exit tubes. Natural sap, artificial sap, and sea water have been successfully perfused, with various additions and deficiencies, within the limits of physiological balance.
In H. ovalis the P.D. remains positive and scarcely reduced in value when normal sea water, at pH 8.1, is perfused in the vacuole. In H. Osterhoutii the P.D. reverses in sign when the perfused solution has a higher pH than 6.5. In both cases a large P.D. persists when the solutions are the same on both sides of the protoplasm. In the absence of external gradients, there must be some internal gradient or asymmetry of the protoplasm itself to account for the P.D. Since appreciable currents are produced, there must be some metabolic activity as a source of energy.
The higher normal P.D. in H. ovalis is not due to the higher KCl content of its sap (as earlier suggested by the author) since it persists nearly unchanged when sea water is substituted for sap.
THE CONDUCTIVITIES OF AQUEOUS SOLUTIONS OF GLYCINE, d,l-VALINE, AND l-ASPARAGINE
Authors: Mehl John W. , Schmidt Carl L. A. 
Published: May 2004

1. The conductivities of aqueous solutions of glycine, d,l-valine, and l-asparagine have been determined, and comparisons have been made with similar data reported in the literature.
2. On the basis of certain theoretical considerations, calculations of the expected conductivities of aqueous solutions of glycine, asparagine, aspartic acid, and glutamic acid have been made and these data have been compared with similar data obtained experimentally.
3. The dissociation constants of the carboxyl groups of aspartic acid and glutamic acid have been calculated from conductivity data.
4. It is shown that alanine has no effect on the ionic atmosphere of solutions of potassium chloride.
A PHYSICAL-CHEMICAL DIFFERENCE IN ANTIBODIES AGAINST THE S AND R VARIANTS OF A SINGLE BACTERIAL STRAIN
Authors: Joffe Eleanore W. 
Published: May 2004

1. Rabbits were immunized with Bact. typhosum 0 901 S and 0 901 R, over a long period. Homologous and heterologous strains were sensitized with sera obtained from weekly bleedings. Agglutination titer was recorded, and the isoelectric points of the bacteria maximally sensitized were determined.
2. 0 901 S maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering a range of pH 4.8 to 5.5.
3. Strain 0 901 R maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering the range of pH 5.0 to 5.9.
4. Both 0 901 S and 0 901 R maximally sensitized with heterologous serum had isoelectric points lower than when sensitized with homologous serum.
5. The isoelectric points of both forms sensitized with increasing concentrations of homologous immune serum were determined. Increasing concentrations of homologous immune serum shifted the isoelectric point of 0 901 R from less than 2.2 for the unsensitized bacteria progressively to the alkaline side until the maximum values previously mentioned were reached. Increasing concentrations of homologous immune serum conferred upon 0 901 S isoelectric points which became only slightly more alkaline in maximal sensitization.
6. The electrophoretic mobilities of 0 901 S and 0 901 R, in each case maximally sensitized with homologous hyperimmune serum, were found to differ significantly over the whole range of pH studied.
A THEORY OF VISUAL INTENSITY DISCRIMINATION
Authors: Hecht Selig 
Published: May 2004

1. A theory of visual intensity discrimination is proposed in terms of the photochemical events which take place at the moment when a photosensory system already adapted to the intensity I is exposed to the just perceptibly higher intensity I+ΔI. Unlike previous formulations this theory predicts that the fraction ΔI/I, after rapidly decreasing as I increases, does not increase again at high intensities, but reaches a constant value which is maintained even at the highest intensities.
2. The theory describes quantitatively the intensity discrimination data of Drosophila, of the bee, and of Mya.
3. With some carefully considered exceptions the intensity discrimination data of the human eye fall into two classes: those with small test areas or with red light, which form a single continuous curve describing the function of the retinal cones alone, and those with larger areas, and with white, orange, and yellow light, which form a double curve showing a clear inflection point, and represent the separate function of the rods at intensities below the inflection point and of the cones at intensities above it.
4. The theory describes all these data quantitatively by treating the rods and cones as two independently functioning photosensory systems in accordance with the well established duplicity idea.
5. In terms of the theory the data of intensity discrimination give critical information about the order of both the photochemical and dark reactions in each photosensory system. The reactions turn out to be variously monomolecular and bimolecular for the different animals.
ON THE MODIFICATION OF TEMPERATURE CHARACTERISTICS. I
Authors: Crozier W. J. 
Published: May 2004

The temperature characteristics for frequency of pulsation in isolated cloacal ends of Holothuria tubulosa are µ = 20,400 from 10 to 20°, 8,000 from 20 to 30°. The critical temperatures 10°, 20°, 30° are related to thermal conditions in the environment.
In sea water with doubled NaCl content µ = 8,000 from 10 to 30°. This is consistent with the specific nature of the temperature characteristics.
The primary effect of increased NaCl is to alter the temperature characteristic curve. At low temperatures the frequency is increased, at higher temperatures diminished. The effect upon frequency is thus of less significance. It is pointed out that such relationships must be taken into account in analyzing the action of reagents upon organisms.
ELECTRIC IMPEDANCE OF HIPPONOË EGGS
Authors: Cole Kenneth S. 
Published: May 2004

Alternating current resistance and capacity measurements have been made from 1.08 103 to 2.32 106 cycles per second on suspensions of unfertilized, fertilized, and swollen unfertilized eggs of the echinoderm Hipponoë esculenta. A simple method has been developed for measuring the volume concentration of eggs in a suspension.
The membrane of the unfertilized egg is practically non-conducting at low frequencies and shows a static capacity of 0.87 µf/cm.2 except perhaps at the highest frequencies. The equivalent specific resistance of the egg interior is 11 times that of sea water.
The membrane of the fertilized egg is practically non-conducting at low frequencies and shows a static capacity 2.5 times that of the unfertilized egg except at the higher frequencies where another reactive element produces a marked effect. The internal resistance is apparently higher than that of the unfertilized egg.
The static capacity per unit area of the membrane decreases as a linear function of the surface area when the eggs are swollen in dilute sea water. In 40 per cent sea water, the capacity falls to about 75 per cent of normal.
THE SIGNIFICANCE OF THE STRUCTURE OF A MEMBRANE FOR ITS SELECTIVE PERMEABILITY
Authors: Wilbrandt W. 
Published: May 2004

The attempt is made to reconcile the two existing theories on the mechanism of selective ion permeability of the cell membrane by taking into account the molecular arrangement in the substance of the membrane. It is shown that the pore theory and the solubility theory are not contradictory, but two aspects of the same problem, one from the thermodynamic point of view, the other from the point of view of molecular theory.
The dried collodion membrane is used as a model in these studies. Its different behavior towards anions and cations is explained on the ground of a quasi-crystalline structure of collodion, the NO3-groups acting as dipoles with the negative charge directed towards the intermolecular spaces, no matter whether these pores are of molecular dimensions or larger. In this way a continuity in the behavior of the ordinary large pored collodion membrane and the dried membrane is established, both theoretically and experimentally. Experiments, with membranes of other cellulose derivatives agree with the mechanism suggested. Membranes of cellophane and ethyl cellulose are negatively charged, membranes of cellulose acetate positively.
From solutions of collodion mixed with basic dyestuffs or alkaloids membranes can be obtained more permeable to anions than to cations in contrast to the ordinary collodion membrane. Membranes can be built which give high potential differences even between two identical electrolyte solutions. The asymmetry lies here within the membrane and is artificially produced by gluing together an ordinary collodion membrane with one previously impregnated with a basic dyestuff or an alkaloid.
THE KINETICS OF PENETRATION
Authors: Jacques A. G. , Osterhout W. J. V. 
Published: May 2004

The rate of entrance of potassium into Nitella flexilis has been investigated, and it has been shown that (a) at the concentrations studied the rate is independent of the external pH between 6 and 8 but it is possible that at lower concentrations a dependence may be found; (b) that it does not vary much with the external potassium concentration between 0.01 and 0.001 M, but appears to vary more with the potassium concentration below this limit.
It has also been shown that the rate is independent of the illumination, in contrast with the penetration of halides into Nitella clavata studied by Hoagland.
It has been found that potassium leaves the cells in distilled water, and since this does not seem to be the result of injury, there is apparently a concentration between 0 and 0.0001 M at which potassium neither enters nor leaves the cell. In Valonia increase of external potassium increases the rate of entrance as shown in the increase in moles of potassium in the sap. In Nitella this is true below an external concentration of 0.001 M. In Valonia this increase is paralleled by the increase in entrance of water so that little or no change in concentration occurs, but in Nitella no growth occurred during the experiment and in consequence the concentration of potassium in the sap increased.
It has been shown that the potassium content of the raw gelatinous sap is no greater than that of its ultrafiltrate, so that it is not possible to assume that any of the potassium is bound up in the cell in colloidal compounds.
It has been pointed out that all the gradients between the sap and the external solution are unfavorable to the entrance of potassium except the potassium bicarbonate gradient. However, on other grounds entrance as potassium bicarbonate is not considered to be very probable.
Various modes of entrance are discussed and it has been concluded that the subject must be investigated further before a definite answer can be given.
STUDIES ON OSMOTIC EQUILIBRIUM AND ON THE KINETICS OF OSMOSIS IN LIVING CELLS BY A DIFFRACTION METHOD
Authors: Lucké Balduin , Larrabee Martin G. , Hartline H. Keffer 
Published: May 2004

1. Osmotic equilibrium and kinetics of osmosis of living cells (unfertilized eggs of Arbacia punctulata) have been studied by a diffraction method. This method consists of illuminating a suspension of cells by parallel monochromatic light and measuring, by means of telescope and scale, the angular dimensions of the resulting diffraction pattern from which the average volume of the cells may be computed.
The method is far less laborious and possesses several advantages over direct measurement of individual cells. The average size of a large number of cells is obtained from a single measurement of the diffraction pattern and thus individual variability is averaged out. The observations can be made at intervals of a few seconds, permitting changes in volume to be followed satisfactorily. During the measurements the cells are in suspension and are constantly stirred.
2. Volumes of cells in equilibrium with solutions of different osmotic pressure have been determined. In agreement with our previous experiments, based upon direct microscope measurements, we have confirmed the applicability of the law of Boyle-van't Hoff to these cells; that is to say, the product of volume and pressure has been found to be approximately constant if allowance be made for the volume of osmotically inactive material of the cell contents.
The volume of osmotically inactive material was found to be, on the average, 12 per cent of the initial cell volume; in eggs from different animals this value ranged from 6 to 20 per cent.
3. Permeability to water of the Arbacia egg has been found to average, at 22°C., 0.106 cubic micra of water per square micron of cell surface, per minute, per atmosphere of difference in osmotic pressure.
4. Permeability to ethylene glycol has been found to average, at 24°C., 4.0 x 10–15 mols, per square micron of cell surface, per minute, for a concentration difference of 1 mol per liter. This is in agreement with the values reported by Stewart and Jacobs.
INHIBITION OF PHOTOSYNTHESIS IN CHLORELLA PYRENOIDOSA BY THE IODO-ACETYL RADICAL
Authors: Kohn Henry I. 
Published: May 2004

Photosynthesis in Chlorella pyrenoidosa is inhibited by iodo-acetic acid and iodo-acetamide, both of which attack the Blackman reaction. Since acetamide is without effect, the iodo-acetyl radical must be responsible. The study of the action of the acid is complicated by the fact that its ions penetrate slowly, if at all, so that negative results with this agent are without significance unless penetration can be established. The absorption spectrum of the cells is not affected by concentrations of iodo-acetamide which completely inhibit photosynthesis. This establishes that the chromophore groups of chlorophyll are not involved, and renders it unlikely that any other part of the molecule is. Inasmuch as cyanide likewise inhibits by way of the Blackman reaction, it would seem necessary to postulate that this complex can be attacked at two different loci, which may or may not be on the same molecule.
The presence of the iodo-acetyl radical also gives rise to three other effects. (1) Concentrations (10–5 M or less) too small to inhibit photosynthesis may increase the rate by interacting with the photochemical complex. (2) Concentrations (ca. 10–4 M) which inhibit photosynthesis increase the rate of respiration. (3) Concentrations (10–3 M or more) higher than those required to inhibit photosynthesis inhibit respiration.
THE ACCELERATING EFFECT OF MANGANOUS IONS ON PHAGE ACTION
Authors: Krueger A. P. , West N. S. 
Published: May 2004

Dilute solutions of MnCl2 or MnSO4 accelerate the lytic effect of phage upon susceptible staphylococci. Under the conditions of our experiments the manganese-containing mixtures lysed regularly 0.5 hour sooner than the controls.
The effect is shown to be due to a lowering of the lytic threshold, i.e. the quantity of phage/bacterium requisite for lysis; Mn++ reduces the ratio from 54 to about 12. In the presence of Mn++ phage distribution is altered and in growing phage-bacteria mixtures the extracellular phage concentration is increased by manganese to approximately 4 times that occurring in the absence of manganese. There appears to be no enhancement of phage formation nor any affect on the rate of bacterial growth. As would be anticipated, for any given initial phage concentration the end titre after completion of lysis is less in the presence of manganese than in its absence. This is due to the reduced lytic threshold produced by Mn++, there consequently being less phage needed to bring about lytic destruction of the bacteria.
THE MOLECULAR WEIGHT AND ISOELECTRIC POINT OF THYROGLOBULIN
Authors: Heidelberger Michael , Pedersen Kai O. 
Published: May 2004

1. The sedimentation constant of hog thyroglobulin is 19.2ċ10–13. That of human thyroglobulin is essentially the same.
2. The specific volume of hog thyroglobulin is 0.72.
3. The isoelectric point of native hog thyroglobulin is at pH 4.58, that of denatured thyroglobulin at pH 5.0.
4. The molecular weight of hog thyroglobulin is, in round numbers, 700,000, as calculated from the sedimentation and diffusion constants, or 650,000, as calculated from the sedimentation equilibrium data.
5. The thyroglobulin molecule deviates markedly from the spherical.
THE DARK ADAPTATION OF THE EYE OF THE HONEY BEE
Authors: Wolf Ernst , Zerrahn-Wolf Gertrud 
Published: May 2004

Bees which are held in a fixed position so that only head movements can be made, respond to a moving stripe system in their visual field by a characteristic motion of the antennae. This reflex can be used to measure the bee's state of photic adaptation. A curve describing the course of dark adaptation is obtained, which shows that the sensitivity of the light adapted bee's eye increases rapidly during the first few minutes in darkness, then more slowly until it reaches a maximum level after 25 to 30 minutes. The total increase in sensitivity is about 1000 fold.
The adaptive range of the human eye is about 10 times greater than for the bee's eye. The range covered by the bee's eye corresponds closely to the adapting range which is covered by the rods of the human eye.
THE VISUAL ACUITY OF THE FIDDLER-CRAB, UCA PUGNAX
Authors: Clark Leonard B. 
Published: May 2004

The visual acuity of the fiddler-crab can be measured at various illuminations by means of its response to a moving visual pattern. The method, although similar to that used by Hecht and Wolf for the bee and Hecht and Wald for Drosophila, must be modified to give consistent results. An explanation of the response to a visual pattern is given in terms of the structure of the eye.
Visual acuity of the crab varies with log I as in man, the bee, and Drosophila. Hecht and Wolf's explanation of the varying visual acuity with illumination in terms of the distribution of functional ommatidia in the eye is supported to that extent.
In the fiddler-crab as in man, monocular and binocular visual acuity is similar with a maximum of 0.0042 for the fiddler-crab. This agrees fairly well with visual acuities of 0.0041, 0.0038, and 0.0032 as found in the field.
In man and the bee, the minimum visual angle corresponds to the minimum angle of two adjacent receptors; in Drosophila and the fiddler-crab the minimum visual angle corresponds to approximately twice the minimum angle between two adjacent receptors.