bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE VISUAL SYSTEMS OF EURYHALINE FISHES
Authors: Wald George 
Published: May 2004

1. The retinas of all marine fishes so far examined except the Labridae, and of all terrestrial vertebrates contain the rhodopsin system alone; those of fresh water fishes the porphyropsin system alone. In the present paper the visual systems of a number of euryhaline fishes are examined—fishes capable of existence in a wide range of salinities, though usually restricted in spawning either to the sea (catadromous) or to fresh water (anadromous).
2. The retinas of the anadromous salmonids (brook trout, rainbow trout, and chinook salmon) contain mixtures of the rhodopsin and porphyropsin systems, predominantly the latter. The retinas of the catadromous eel and the killifish also contain mixtures of both systems, but in reverse proportions. The retinas of the anadromous white perch and alewife contain the porphyropsin system alone.
3. There is therefore an extensive parallelism between the salinity relations of these animals and the composition of their visual systems. All of them possess predominantly or exclusively the visual system commonly associated with the environment in which the fish spawns.
4. These patterns are fixed genetically, and are to a first approximation independent of the history of the individual. They may represent transitional stages in the evolutionary migration of fishes to and from the sea. The presence of both types of visual system in the retinas of some euryhaline fishes incidentally satisfies one formal requirement of two-component color vision.
THE VISUAL SYSTEM AND VITAMINS A OF THE SEA LAMPREY
Authors: Wald George 
Published: May 2004

The porphyropsin-vitamin A2 cycle has been found heretofore only in the retinas of bony fishes capable of existence in fresh water. Cyclostomes, due to their primitive and isolated phylogenetic position, might be expected to possess the rhodopsin-vitamin A1 cycle common to marine elasmobranchs, almost all marine teleosts, and all terrestrial vertebrates so far examined. Yet the anadromous sea lamprey, Petromyzon marinus, possesses primarily the porphyropsin system, like an anadromous teleost. This observation greatly extends the phylogenetic association of vitamin A2 with the capacity for freshwater existence.
Compared with freshwater and anadromous teleosts, the lamprey retina contains the porphyropsin system in extremely low concentration.
The remaining eye tissues, like the retina, contain both vitamins A1 and A2, the latter greatly predominant. The livers of larval and adult lampreys, however, appear to contain vitamin A1 alone. This situation also is not without teleost precedent, since the carp and certain anadromous salmonids display similar reversals of vitamin A pattern in the liver and eye tissues.
COUNTERACTING THE RETARDING AND INHIBITORY EFFECTS OF STRONG ULTRAVIOLET ON FUCUS EGGS BY WHITE LIGHT
Authors: Whitaker D. M. 
Published: May 2004

1. Strong dosages (20,000–50,000 ergs per mm.2) of ultraviolet light, predominantly of the wave-length 2537 Å, greatly retard and inhibit the development of rhizoids in Fucus eggs irradiated at about 8 hours after fertilization.
2. If white light shines on the eggs after the irradiation by ultraviolet is terminated, the white light causes a considerable degree of recovery from the retarding and inhibiting effects.
3. If strong white light shines on the eggs during the ultraviolet irradiation, its effect is even more marked in protecting the cells from the damaging effects of the ultraviolet.
THE ROLE OF CARBONIC ANHYDRASE IN CERTAIN IONIC EXCHANGES INVOLVING THE ERYTHROCYTE
Authors: Jacobs M. H. , Stewart Dorothy R. 
Published: May 2004

1. The acceleration by bicarbonates of the swelling and hemolysis of erythrocytes in solutions of ammonium salts, first reported by Ørskov, is strikingly dependent upon carbonic anhydrase, being almost abolished by inhibitors of this enzyme such as KCN and sulfanilamide, and under suitable conditions being enhanced by its addition to the external solution. This behavior gives support to the theory of "catalyzed diffusion" as an explanation of the Ørskov effect.
2. The inhibitory effects of both sulfanilamide and KCN seem to be capable of complete reversal on washing the erythrocytes in isotonic salt solutions. The full effect of KCN appears almost instantly; that of sulfanilamide requires a period measured in seconds, or possibly even in minutes, to reach its maximum, the delay presumably being due to the slower penetration of the erythrocyte by this substance. Under favorable conditions the effect of concentrations of sulfanilamide of a few hundredths of a milligram per cent can be demonstrated. No similar effects have been obtained with sulfapyridine.
3. Bicarbonates also have a "catalytic" effect on the response of the internal pH of erythrocytes to changes in that of their surroundings. The resulting volume changes of the cell, which otherwise frequently require many minutes for their completion, may take place within a few seconds in the presence of low concentrations of bicarbonates. At a given pH value the effect of the latter substances is chiefly on the rate of the change and only to a minor extent on its magnitude. It may be further accelerated under appropriate conditions by the addition to the cell suspension of carbonic anhydrase, and can be almost abolished by KCN and by sulfanilamide.
4. Volume changes of erythrocytes associated with exchanges of Cl' for SO4'' ions are greatly accelerated by low concentrations of bicarbonates, this effect being likewise dependent upon carbonic anhydrase. There is some evidence that in this case the exchange takes place, at least in part, in two steps: Cl' for HCO3' and HCO3' for SO4''.
THE PHOTOSYNTHETIC EFFICIENCY OF PHYCOCYANIN IN CHROOCOCCUS, AND THE PROBLEM OF CAROTENOID PARTICIPATION IN PHOTOSYNTHESIS
Authors: Emerson Robert , Lewis Charlton M. 
Published: May 2004

The absorption spectra of the principal pigment components extracted from Chroococcus cells have been measured, and their sum compared with the absorption of a suspension of living cells. The agreement was sufficiently close so that it was concluded the absorption spectra of the extracted and separated pigment components could be used to obtain estimates of the relative absorption of the various components in the living cells.
The quantum yield of Chroococcus photosynthesis was measured at a succession of wave lengths throughout the visible spectrum, and the dependence of yield on wave length was compared with the proportions of light absorbed by the pigment components. This comparison showed beyond reasonable doubt that the light absorbed by phycocyanin is utilized in photosynthesis with an efficiency approximately equal to that of the light absorbed by chlorophyll. The light absorbed by the carotenoid pigments of Chroococcus seems for the most part to be unavailable for photosynthesis. The results leave open the possibility that light absorbed by the carotenoids is active in photosynthesis, but with an efficiency considerably lower than that of chlorophyll and phycocyanin. It is also possible that the light absorbed by one or a few of the several carotenoid components is utilized with a high efficiency, while the light absorbed by most of the components is lost for photosynthesis.
PURIFICATION OF THROMBIN
Authors: Milstone H. 
Published: May 2004

1. Under certain conditions crude prothrombin changes to thrombin without the addition of extraneous activators and in the absence of ionic calcium.
2. Thrombin is soluble in 0.45 saturated ammonium sulfate, whereas crude prothrombin is not.
3. Partially purified thrombin is comparatively stable in concentrated ammonium sulfate solutions at pH 5.2.
4. A method based on the above facts yields a thrombin preparation the specific activity of which is 100 to 175 times the potential specific activity of whole plasma.
THE INFLUENCE OF DETERGENTS ON SOME PHYSIOLOGICAL PHENOMENA, ESPECIALLY ON THE PROPERTIES OF THE STELLATE CELLS OF THE FROG LIVER
Authors: Höber Rudulf , Höber Josephine 
Published: May 2004

1. After a consideration of the physicochemical properties of detergents, it was deemed worth while to study some of their physiological effects. As nonpolar-polar electrolytes, the detergents are surface-active and as such cytolytics; but probably due to their dispersing and wetting properties, they are cytolytic in a fashion different from that of other cytolytics. The detergents tested were alkyl sulfonates, alkyl sulfosuccinates, and bile salts.
2. The cytolytic power has been tested in two ways, (1) with red cells by following the escape of hemoglobin, (2) with muscles by measuring the development of an injury potential. In both series of experiments the threshold concentrations of action have been determined. The effect on the potentials has proved to be, in general, reversible.
3. The hemolytic and the myolytic power run fairly parallel to the surface activity.
4. Dehydrocholate has been found to be lacking in nonpolar-polar properties.
5. The stellate cells (Kupffer cells) of the Ringer-perfused frog liver are unable to take up colloidal dyestuffs (trypan blue and soluble blue R), except after addition of a small amount of serum to the perfusing Ringer solution. Only under the latter conditions, the uptake of dye is increased by adding a detergent. This seems to be due to the combined action of the proteins and the detergents.
6. The effect of relatively high concentrations of detergent is disintegration of the stellate cells; viz., cytolysis. There are reasons to assume that small concentrations, which produce a threshold increase of the dyestuff uptake, raise the functional activity.
STUDIES ON CELL METABOLISM AND CELL DIVISION
Authors: Krahl M. E. , Jandorf Bernhard J. , Clowes G. H. A. 
Published: May 2004

1. Methods suitable for the determination of diphosphothiamine (cocarboxylase) in eggs of Arbacia punctulata have been developed. Quantitative extraction of the cocarboxylase was effected by combining the use of thiamine hydrochloride in the extraction fluid with critical adjustment of the pH of extraction to pH 6.3–6.7.
2. The unfertilized eggs were found to contain the equivalent of 2 to 3 micrograms of natural yeast cocarboxylase per gm. of wet eggs; the cocarboxylase content of the 30 minute and 10 hour fertilized eggs was somewhat less (Table III).
3. In preliminary experiments, Arbacia egg cytolysates were found to cause pyruvic acid to disappear. The rate of such disappearance was apparently greater under aerobic than under anaerobic conditions; it was also greater for cytolysates from fertilized eggs than for cytolysates from unfertilized eggs (Table IV).
STUDIES ON CELL METABOLISM AND CELL DIVISION
Authors: Jandorf Bernhard J. , Krahl M. E. 
Published: May 2004

1. The diphosphopyridine nucleotide content of Arbacia eggs has been measured manometrically and found to be approximately 250–500 micrograms per gm. wet weight of eggs, the value varying with individual egg samples and with the state of development of the eggs. Of the total diphosphopyridine nucleotide present, approximately 25–40 per cent is in an alkali-stable, presumably the dihydro, form.
2. Tests for triosephosphate and glutamic acid dehydrogenases carried out on Arbacia egg cytolysates were negative.
THE CHLOROPHYLL-PROTEIN COMPLEX
Authors: Fishman Myer , Moyer Laurence S. 
Published: May 2004

1. Reported effects of different conditions on the stability of the purified chlorophyll-protein complex have been confirmed.
2. The electrophoretic behavior of the chlorophyll-protein complex prepared from two unrelated species of plants (Aspidistra elatior and Phaseolus vulgaris) has been investigated and shown to be dissimilar. In M/50 acetate buffer at 25°C, the isoelectric point of the complex from Phaseolus is at pH 4.70, whereas that from Aspidistra is at pH 3.9 (extrapolated). These values fall within the usual range of protein isoelectric points.
3. Treatment with weak acids causes an irreversible denaturation of the protein complex from both species, with a resultant shift in the mobility-pH curves to more basic values.
4. Differences in electrophoretic behavior between the chlorophyll-protein complex and the cytoplasmic proteins of Phaseolus have been demonstrated. The isoelectric point of the latter is at pH 4.22.
HYDROSTATIC PRESSURE AND TEMPERATURE IN RELATION TO STIMULATION AND CYCLOSIS IN NITELLA FLEXILIS
Authors: Harvey E. Newton 
Published: May 2004

Nitella flexilis cells are not stimulated to "shock stoppage" of cyclosis by suddenly evacuating the air over the water or on sudden readmission of air, or on suddenly striking a piston in the water-filled chamber in which they are kept with a ball whose energy is 7.6 joules, provided the Nitella cell is not moved by currents against the side of the chamber.
Sudden increases in hydrostatic pressure from zero to 1000 lbs. or 0 to 5000 lbs. per square inch or 5000 to 9000 lbs. per square inch usually do not stimulate to "shock stoppage" of cyclosis, but some cells are stimulated. Sudden decreases of pressure are more likely to stimulate, again with variation depending on the cell.
In the absence of stimulation, the cyclosis velocity at 23°C. slows as the pressure is increased in steps of 1000 lbs. per square inch. In some cells a regular slowing is observed, in others there is little slowing until 4000 to 6000 lbs. per square inch, when a rapid slowing appears, with only 50 per cent to 30 per cent of the original velocity at 9000 lbs. per square inch. The cyclosis does not completely stop at 10000 lbs. per square inch. The pressure effect is reversible unless the cells have been kept too long at the high pressure.
At low temperatures (10°C.) and at temperatures near and above (32°–38°C.) the optimum temperature for maximum cyclosis (35–36°C.) pressures of 3000 to 6000 lbs. per square inch cause only further slowing of cyclosis, with no reversal of the temperature effect, such as has been observed in pressure-temperature studies on the luminescence of luminous bacteria.
Sudden increase in temperature may cause shock stoppage of cyclosis as well as sudden decrease in temperature.
THE RELATIONS OF TEMPERATURE TO THE POTASSIUM EFFECT AND THE BIOELECTRIC POTENTIAL OF VALONIA
Authors: Blinks L. R. 
Published: May 2004

The effect of temperature upon the bioelectric potential across the protoplasm of impaled Valonia cells is described. Over the ordinary tolerated range, the P.D. is lowest around 25°C., rising both toward 15° and 35°. The time curves are characteristic also. The magnitude of the temperature effect can be controlled by changing the KCl content of the sea water (normally 0.012 M): the magnitude is greatly reduced at 0.006 M KCl, enhanced at 0.024 M, and greatly exaggerated at 0.1 M KCl.
Conversely, temperature controls the magnitude of the potassium effect, which is smallest at 25°, with a cusped time course. It is increased, with a smoothly rising course, at 15°, and considerably enhanced, with only a small cusp, at 35°. A temporary "alteration" of the protoplasmic surface by the potassium is suggested to account for the time courses. This alteration does not occur at 15°; the protoplasm recovers only slowly and incompletely at 25°, but rapidly at 35°, in such fashion as to make the P.D. more negative than at 15°. This would account for the temperature effects observed in ordinary sea water.
STUDIES ON THE METABOLISM OF AUTOTROPHIC BACTERIA
Authors: Vogler K. G. 
Published: May 2004

In a study of chemosynthesis (the fixation of CO2 by autotrophic bacteria in the dark) in Thiobacillus thiooxidans, the data obtained support the following conclusions:
1. CO2 can be fixed by "resting cells" of Thiobacillus thiooxidans; the fixation is not "growth bound."
2. The physiological condition of the cell is of considerable importance in determining CO2 fixation.
3. CO2 fixation can occur in the absence of oxidizable sulfur in "young" cells. The extent of this fixation appears to be dependent upon the pCO2.
4. CO2 fixation can also occur under anaerobic conditions and the presence of sulfur does not influence such fixation.
5. However, in the CO2 fixation by cells in the absence of sulfur, only a limited amount of CO2 can be fixed. This amount is approximately 40 µl. CO2 per 100 micrograms bacterial nitrogen. After a culture has utilized this amount of CO2 it no longer has the ability to fix CO2 but releases it during its respiration.
6. Relatively short periods of sulfur oxidation can restore the ability of cells to fix CO2 under conditions where sulfur oxidation is prevented.
7. It is possible to oxidize sulfur in the absence of CO2 and to store the energy thus formed within the cell. It is then possible to use this energy at a later time for the fixation of CO2 in the entire absence of sulfur oxidation.
8. Cultures of Thiobacillus thiooxidans respiring on sulfur utilize CO2 in a reaction which proceeds to a zero concentration of CO2 in the atmosphere.
9. CO2 may act as an oxidizing agent for sulfur.
10. Hydrogen is not utilized by the organism.
11. It is possible to selectively inhibit sulfur oxidation and CO2 fixation.
THE ANTIGENICITY OF d-RIBONUCLEASE; THE INHIBITION OF THE ENZYME BY ITS HOMOLOGOUS IMMUNE SERUM
Authors: Smolens J. , Sevag M. G. 
Published: May 2004

The enzyme d-ribonuclease is antigenic. Antisera, prepared by three different methods, reacted against antigen dilutions up to one million.
Apparently the homologous antiserum, when combined with the d-ribonuclease inhibited the activity of the enzyme from 10 to 30 per cent.
HUMORAL RHEOLOGY
Authors: Copley Alfred L. , Krchma Ludwig C. , Whitney Mary E. 
Published: May 2004

1. A modified falling ball viscometer (rolling ball viscometer) for blood and other humors is presented. It is capable of easily measuring flow properties at several stresses, as is required to define satisfactorily the properties of anomalous flow systems. At high shearing stresses, apparent specific viscosity values of 2.5 + are observed, corresponding to 2.2 ±0.2 reported as possible with the biological viscometer of Whittaker and Winton.
2. Previous references to the anomalous flow properties of blood were verified. It was demonstrated that these systems conform to the Bingham concept of anomalous flow. To define completely the flow properties of such systems it is necessary to make determinations at at least two shearing stresses, preferably more. Data are reported for the pseudoviscosity and yield value, the latter being possibly the most specific property of the three bloods studied.
3. Heparin in increasing amounts tended to decrease the apparent viscosity, pseudoviscosity, and yield value of blood. Similar increases of heparin also reduced the viscosites of the serum and plasma.
4. The ratio of the apparent viscosity of blood and its plasma was found to be reasonably constant as reported by Trevan. However, as the apparent viscosity is a function of the shearing stress, it is believed that the relationship for the calculations of corpuscular concentrations, such as the Whittaker and Winton modification of the Hatschek formula, is specific for the instrument and conditions of tests by which it was determined.
5. Heparinized blood was found to exhibit thixotropy, dilatancy, and age-hardening phenomena.
ALLOCATION OF ELECTRICAL RESPONSES FROM THE COMPOUND EYE OF GRASSHOPPERS
Authors: Jahn Theodore Louis , Wulff Verner John 
Published: May 2004

1. The effect of extirpation of the optic ganglion on the ERG and on electrical oscillations recorded from the compound eye was determined.
2. Extirpation of the optic ganglion prevents the occurrence of oscillations, and it is concluded that they originate in the ganglion.
3. Extirpation of the optic ganglion changes the wave form of the ERG. The sharpness of the b-wave is decreased, the relative magnitude of the c-wave is increased, and the d-wave is obliterated. These changes can be explained by assuming that the ERG is the algebraic sum of two potential changes, one in the compound eye, and another, of opposite sign in the ganglion. This assumption is supported by data from a number of experiments in which the electrode positions were varied.
4. The explanation of the present data (which indicates two sites of origin of the ERG) is similar to the three-component theory which accounts for the complex wave form of the vertebrate ERG.
STUDIES ON THE METABOLISM OF AUTOTROPHIC BACTERIA
Authors: Vogler K. G. , LePage G. A. , Umbreit W. W. 
Published: May 2004

The data of this paper indicate that:
1. The "energy of activation" (µ) of sulfur oxidation by the autotrophic bacterium, Thiobacillus thiooxidans, is similar to that of other respirations.
2. The pH of the menstruum does not influence the respiration on sulfur between the limits of pH 2 to 4.8 once contact between the bacterial cell and the sulfur particle has been established but it does influence the rate at which such contact occurs.
3. The pO2 has little effect upon the respiration of this organism.
4. Most organic materials have no detectable effect upon the respiration of Thiobacillus thiooxidans, but the organic acids of terminal respiration seem to stimulate the respiration in the absence of oxidizable sulfur and certain of them inhibit sulfur oxidation.
5. In so far as inhibitor studies on intact cells are trustworthy, sulfur oxidation goes through iron-containing systems similar to cytochrome. It is possible that the oxygen contained in the sulfuric acid formed during sulfur oxidation is derived from the oxygen of the water.
THE pH STABILITY OF PROTYROSINASE AND TYROSINASE
Authors: Allen Thomas Hunter , Otis Arthur B. , Bodine Joseph Hall 
Published: May 2004

1. pH stability diagrams for protyrosinase and for tyrosinase were constructed.
2. Above pH 7.30 protyrosinase is unstable. Between pH 7.30 and pH 9.30 there is a partial destruction. Beyond pH 9.30 it changes irreversibly into tyrosinase which in turn is destroyed beyond pH 10.12.
3. Through the lower ranges of pH protyrosinase is less stable than tyrosinase The former is destroyed below pH 4.80, while the latter is unaffected until the pH drops below 4.10.
4. The tyrosinase produced at high pH values resembles that produced by other methods.
THE USE OF A MEASURABLE CAUSE OF DEATH (HEMORRHAGE) FOR THE EVALUATION OF AGING
Authors: Simms Henry S. 
Published: May 2004

1. There has been need for a reliable experimental standard for the process of aging. Chronological age is a poor standard owing to irrelevant changes and individual variability. Longevity does not indicate the rate of aging because it depends not only upon aging but also upon intrinsic death rate, individual variability, and the selective effect of experimental treatment upon resistance to specific diseases.
2. The use of a known measurable cause of death (hemorrhage) on healthy animals of various ages reproduces the known mortality curve for rats, and differentiates this measure of the aging process from individual variation.
3. The possibilities for the use of this method in determining the nature of the aging process are pointed out.