bluuebunny/crossref_metadata_2025 huggingface dataset:
TEMPERATURE AND CRITICAL ILLUMINATION FOR REACTION TO FLICKERING LIGHT
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

For the teleosts Xiphophorus montezuma, Platypoecilius maculatus, and their F1 hybrids the temperature characteristics (µ in Arrhenius' equation) are the same for the shift of the low intensity and the high intensity segments of the respective and different flicker response contours (critical intensity I as a function of flash frequency F, with light time fraction constant, at 50 per cent). The value of µ is 12,500 calories or a very little less, over the range 12.5 to 36°. This shows that 1/I can be understood as a measure of excitability, with F fixed, and that the excitability is governed by the velocity of a chemical process common to both the classes of elements represented in the duplex performance curve (rods and cones).

It is accordingly illegitimate to assume that the different shapes of the rod and cone branches of the curves are determined by differences in the chemical mechanisms of excitability. It is also forbidden to assume that the differing form constants for the homologous segments in the curves for two forms (X. and P.) are the reflections of a difference in the chemical factors of primary excitability. These differences are determined by statistical factors of the distribution of excitabilities among the elements implicated in the sensory effect vs. intensity function, and are independent of temperature and of the temperature characteristic.

It must be concluded that the physicochemical nature of the excitatory process cannot be deduced from the shape of the performance contour.

The form constants (σ'log I and Fmax.) for F vs. log I are specifically heritable in F1, although µ is here the same as for X. and P. In an intergeneric cross one cannot in general expect Mendelian simplicity of segregation in subsequent generations, and in the present case we find that F2 individuals are indistinguishable from F1, both as regards F vs. log I and as regards the variation of I within a group of 17 individuals. The result in F2 definitely shows, however, that certain specific statistical form constants for the F-log I contour are transmissible in inheritance. It is pointed out that there thus is provided an instance in which statistical (distribution) factors in performance characteristics involving the summating properties of assemblages of cellular units are heritable in a simple manner without the implication of detectable differences in chemical organization of the units involved. This has an important bearing upon the logic of the theory of the gene.
THE CHEMISTRY OF HUMAN SKIN
Authors: Wilkerson Vernon A.
Published: May 2004

1. The electrophoretic activity of particles of human skin in distilled water and different concentrations of salt solutions has been studied. The electrokinetic potential and the charge density were determined and comparisons made with results obtained by electroendosmosis.

2. The electrokinetic potential is ultimately decreased if sufficient salt is added. The order of inhibition is Al > Ca > Ba > K > Na.

3. The lyotrophic series Li > Na > K > Rb and Cl > I > Br express respectively the comparative effect of the monovalent cations and anions upon the electrokinetic potential of the skin.

4. Since both electrophoresis and electroendosmosis are dependent upon the electrokinetic potential, it follows from the results obtained, that the greatest rate of flow through the human skin under the force of an applied electrical current would be given by concentrations of neutral salts between 0.0001 M and 0.0002 M.
THE REACTIONS OF DENATURED EGG ALBUMIN WITH FERRICYANIDE
Authors: Anson M. L.
Published: May 2004

The following facts have been established experimentally.

1. In the presence of the synthetic detergent, Duponol PC, there is a definite reaction between dilute ferricyanide and denatured egg albumin. 0.001 mM of ferrocyanide is formed by the oxidation of 10 mg. of denatured egg albumin despite considerable variation in the time, temperature, and pH of the reaction and in the concentration of ferricyanide.

2. If the concentration of ferricyanide is sufficiently high, then the reaction between ferricyanide and denatured egg albumin in Duponol solution is indefinite. More ferrocyanide is formed the longer the time of reaction, the higher the temperature, the more alkaline the solution, and the higher the concentration of ferricyanide.

3. Denatured egg albumin which has been treated with formaldehyde or iodoacetamide, both of which abolish the SH groups of cysteine, does not reduce dilute ferricyanide in Duponol PC solution.

4. Cysteine is the only amino acid which is known to have a definite reaction with ferricyanide or which is known to react with dilute ferricyanide at all. The cysteine-free proteins which have been tried do not reduce dilute ferricyanide in Duponol PC solution.

5. Concentrated ferricyanide oxidizes cystine, tyrosine, and tryptophane and proteins which contain these amino acids but not cysteine. The reactions are indefinite, more ferrocyanide being formed, the higher the temperature and the concentration of ferricyanide.

6. The amount of ferrocyanide formed from denatured egg albumin and a given amount of ferricyanide is less in the absence than in the presence of Duponol PC.

7. The amount of ferrocyanide formed when denatured egg albumin reacts with ferricyanide in the absence of Duponol PC depends on the temperature and ferricyanide concentration throughout the whole range of ferricyanide concentrations, even in the low range of ferricyanide concentrations in which ferricyanide does not react with amino adds other than cysteine.

The foregoing results have led to the following conclusions which, however, have not been definitely proven.

1. The definite reaction between denatured egg albumin in Duponol PC solution and dilute ferricyanide is a reaction with SH groups whereas the indefinite reactions with concentrated ferricyanide involve other groups.

2. The SH groups of denatured egg albumin in the absence of Duponol PC react with iodoacetamide and concentrated ferricyanide but they do not all react rapidly with dilute ferricyanide.

3. Duponol PC lowers the ferricyanide concentration at which the SH groups of denatured egg albumin react with ferricyanide. The SH groups of denatured egg albumin, however, are free and accessible even in the absence of Duponol PC.
PHYSICOCHEMICAL PROPERTIES OF THE PROTEOLYTIC ENZYME FROM THE LATEX OF THE MILKWEED, ASCLEPIAS SPECIOSA TORR. SOME COMPARISONS WITH OTHER PROTEASES
Authors: Winnick Theodore , Davis Alva R. , Greenberg David M.
Published: May 2004

1. A study has been made of the properties of a hitherto unreported proteolytic enzyme from the latex of the milkweed, Asclepias speciosa. The new protease has been named asclepain by the authors.

2. The results of chemical, diffusion, and denaturation tests indicate that asclepain is a protein.

3. Like papain, asclepain dots milk and digests most proteins, particularly if they are dissolved in concentrated urea solution. Unlike papain, asclepain did not clot blood.

4. The activation and inhibition phenomena of asclepain resemble those of papain, and seem best explained on the assumption that free sulfhydryl in the enzyme is necessary for proteolytic activity. The sulfhydryl of asclepain appears more labile than that of papain.

5. The measurement of pH-activity curves of asclepain on casein, ovalbumin, hemoglobin, edestin, and ovovitellin showed no definite digestion maxima for most of the undenatured proteins, while in urea solution there were well defined maxima near pH 7.0. Native hemoglobin and ovovitellin were especially undigestible, while native casein was rapidly attacked.

6. Temperature-activity curves were determined for asclepain on hemoglobin, casein, and milk solutions. The optimum temperature was shown to increase with decreasing time of digestion.
SOME CHEMICAL ASPECTS OF THE POTASSIUM EFFECT
Authors: Osterhout W. J. V.
Published: May 2004

The ability of Nitella to distinguish electrically between Na+ and K+ (potassium effect) appears to depend on several organic substances (or groups of substances). Of these RMK and RSK determine the mobility and partition coefficient (S) respectively of K+ while RMNa and RSNa do the same for Na+.

These substances can vary independently and this variation is susceptible to experimental control.
STUDIES ON PITUITARY LACTOGENIC HORMONE
Authors: Li Choh Hao , Lyons William R. , Evans Herbert M.
Published: May 2004

The Tiselius technique of electrophoresis has been used to study the homogeneity and mobility of pituitary lactogenic hormone. The lactogenic preparation employed by us shows only one sharp band in schlieren photographs, indicating a high degree of homogeneity. From the determination of the mobility of the hormone at different hydrogen ion concentrations in acetate and phosphate buffer of ionic strength 0.055, the isoelectric point was found to be 5.70 and the

See PDF for Equation

value 4.5 x 10–5.

The difference in the mobility reported for White's crystalline preparation and that found with our high potency lactogenic preparation is discussed.
THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA
Authors: French C. S.
Published: May 2004

Absorption curves have been obtained in the spectral region of 450 to 900 mµ for the water soluble cell juice of four species of photosynthetic bacteria, Spirillum rubrum (strain S1), Rhodovibrio sp. (strain Gaffron), Phaeomonas sp. (strain Delft), and Streptococcus varians (strains C11 and orig.).

These curves all show maxima at 790 and 590 mµ due to bacteriochlorophyll, whose highest band, however, occurs at 875, 855, or 840 mµ depending on the species. The bacteria that appear red rather than brown have a band at 550 mµ due to a carotinoid pigment. An absolute absorption curve of bacteriophaeophytin has maxima at 530 and 750 mµ.

The extraction of cell juice by supersonic vibration does not change the position of the absorption bands or of the light absorbing capacity of the pigment.
REACTION TO VISUAL FLICKER IN THE NEWT TRITURUS
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

The flicker response curve for the newt Triturus viridescens (water phase) has much the same quantitative structure as that found with various fresh-water teleosts at the same temperature (21.5°). The variability of critical intensity and of critical flash frequency likewise follows the same rules. The cone portion of the F - log I curve is much more widely spread, however. This, and the rather low maximum to which the rod curve rises, produce a considerable overlapping of the two parts additively fused.

In addition, and to an extent which differs in various individuals, there is apparent a slight departure from the probability integral form of the cone curve. Reasons are given for considering that this is possibly connected with the role of an additional (small) number of (perhaps temporary, or developmental) retinal elements in addition to the typical rods and cones.
THE SENSIBILITY OF THE NOCTURNAL LONG-EARED OWL IN THE SPECTRUM
Authors: Hecht Selig , Pirenne Maurice Henri
Published: May 2004

Infrared radiation (750–1500 mµ) produces no iris contraction in the typically nocturnal long-eared owl even when the energy content is millions of times greater than that of green light which easily elicits a pupil change. The energies in different parts of the visible spectrum required for a minimal iris response yield a spectral visibility curve for the owl which is the same as the human visibility curve at low light intensities. Functionally, the owl's vision thus corresponds to the predominantly rod structure of its retina, and the idea that nocturnal owls have a special type of vision sensitive to infrared radiation for seeing in the woods at night is erroneous.
THE ELECTRICAL CONDUCTANCE OF SUSPENSIONS OF ELLIPSOIDS AND ITS RELATION TO THE STUDY OF AVIAN ERYTHROCYTES
Authors: Velick Sidney , Gorin Manuel
Published: May 2004

1. The theory of electrical conductance of colloidal suspensions has been extended to cover the case of ellipsoids with three axes different.

2. The results have been applied to suspensions of ellipsoidal erythrocytes of birds.

3. It has been shown that fluctuations in electrical resistance of suspensions of erythrocytes after stirring are due to streaming orientation of the cells.

4. The theory has been extended to cover four cases of orientation and tested experimentally in specially designed flow cells by electrical and optical methods.

5. Application of the flow method to the study of the shape of colloidal particles is discussed.
THE INFLUENCE OF SODIUM CHLORIDE AND TEMPERATURE ON THE ENDOGENOUS RESPIRATION OF B. CEREUS
Authors: Ingram M.
Published: May 2004

Measurements were made of the rate of consumption of oxygen by suspensions of B. cereus, in sodium chloride solutions of concentration up to 1.8 M and over a range of pH from 6.0 to 7.5. It was found:

1. That the temperature coefficient was independent of the presence of sodium chloride in concentrations between 0.2 and 1.8 M, although the rate of respiration was lowered considerably under these conditions.

2. That in the presence of concentrations of sodium chloride less than 0.2 M, the rate of respiration was increased, and so was the temperature coefficient.

3. That small changes in the temperature coefficient occurred when the pH was changed. The temperature coefficient was higher the higher the rate of respiration.

These data may be more readily interpreted by the hypothesis that the temperature coefficient is controlled by some master reaction, than by that which supposes that the temperature coefficient is determined by protoplasmic viscosity.
NEW EXPERIMENTS ON ANOMALOUS OSMOSIS
Authors: Sollner Karl , Abrams Irving
Published: May 2004

1. It is impossible to reproduce Loeb's observations on anomalous osmosis with membranes prepared from relatively pure brands of collodion, whereas positive effects can be obtained using collodion containing acidic impurities.

2. The inactive (purer) collodion membranes may be activated by oxidation with NaOBr solution.

3. Properly oxidized membranes give much greater anomalous osmotic effects than those described by Loeb.
CHEMICAL RESTORATION IN NITELLA
Authors: Osterhout W. J. V.
Published: May 2004

Leaching in distilled water may remove irritability and the potassium effect in Nitella but both of these may be restored by appropriate treatment with guanidine.
ENZYMES IN ONTOGENESIS (ORTHOPTERA)
Authors: Allen Thomas Hunter , Bodine Joseph Hall
Published: May 2004

1. Protyrosinase from the egg of the grasshopper, Melanoplus differentialis, can be activated by excess sodium oleate or Aerosol.

2. The 3:4 quinone products of the reaction of activated protyrosinase with tyramine or tyrosine will oxidize ascorbic acid to dehydroascorbic acid.

3. The velocity of this latter oxidation of ascorbic acid increases with the amount of tyramine or tyrosine.

4. The oxidation of ascorbic acid by the tyramine-tyrosinase reaction delays the time of appearance of a red color associated with an indole quinone intermediary product in the formation of melanin.

5. Protyrosinase, in itself, and in the presence of tyrosinase substrates does not bring about the oxidation of ascorbic acid.

6. A naturally occurring substrate in a preparation of protyrosinase, sufficient to cause the oxidation of ascorbic acid, can be removed by dialysis against a 0.9 per cent sodium chloride solution.

7. Dialysis against such a solution does not change the properties of protyrosinase; the inactive enzyme must still be activated before it will catalyze the oxidation of tyramine or tyrosine.

8. When the natural substrate, tyrosine, or tyramine is absent, activation of protyrosinase does not result in the oxidation of ascorbic acid.
THE EFFECT OF SWELLING ON THE RESPIRATION OF ERYTHROCYTES
Authors: Hunter F. R. , Banfield W. G.
Published: May 2004

1. Oxygen consumption measurements made while a chicken erythrocyte swells show no increase over the control value.

2. There is no change in the rate of anaerobic glycolysis in beef erythrocytes when they swell.

3. The above statements are true whether the cells swell from a shrunken condition back to the normal volume, or swell from the normal to the hemolytic volume.

4. These data add a further test of the hypothesis that a relationship exists between the cell membrane and its respiratory activity.
ISOLATION, CRYSTALLIZATION, AND PROPERTIES OF PEPSIN INHIBITOR
Authors: Herriott Roger M.
Published: May 2004

A method has been described for the isolation and crystallization of swine pepsin inhibitor from swine pepsinogen.

Solubility experiments and fractional recrystallization show no drift in specific activity.

The reversible combination of pepsin with the inhibitor was found to obey the mass law.

The inhibitor is quite specific, failing to act on other proteolytic and milk clotting enzymes. The inhibitor is destroyed by pepsin at pH 3.5.

Chemical and physical studies indicate that the inhibitor is a polypeptide of approximately 5,000 molecular weight with an isoelectric point at pH 3.7. It contains arginine, tyrosine, but no tryptophane and has basic groups in its structure.
THE SULFHYDRYL GROUPS OF EGG ALBUMIN
Authors: Anson M. L.
Published: May 2004

1. 1 cc. of 0.001 M ferricyanide, tetrathionate, or p-chloromercuribenzoate is required to abolish the SH groups of 10 mg. of denatured egg albumin in guanidine hydrochloride or Duponol PC solution. Both the nitroprusside test and the ferricyanide reduction test are used to show that the SH groups have been abolished.

2. 1 cc. of 0.001 M ferrocyanide is formed when ferricyanide is added to 10 mg. of denatured egg albumin in neutral guanidine hydrochloride or urea solution. The amount of ferricyanide reduced to ferrocyanide by the SH groups of the denatured egg albumin is, within wide limits, independent of the ferricyanide concentration.

3. Ferricyanide and p-chloromercuribenzoate react more rapidly than tetrathionate with the SH groups of denatured egg albumin in both guanidine hydrochloride solution and in Duponol PC solution.

4. Cyanide inhibits the oxidation of the SH groups of denatured egg albumin by ferricyanide.

5. Some samples of guanidine hydrochloride contain impurities which bring about the abolition of SH groups of denatured egg albumin and so interfere with the SH titration and the nitroprusside test. This interference can be diminished by using especially purified guanidine hydrochloride, adding the titrating agent before the protein has been allowed to stand in guanidine hydrochloride solution, and carrying out the nitroprusside test in the presence of a small amount of cyanide.

6. The SH groups of egg albumin can be abolished by reaction of the native form of the protein with iodine. It is possible to oxidize all the SH groups with iodine without oxidizing many of the SH groups beyond the S-S stage and without converting many tyrosine groups into di-iodotyrosine groups.

7. p-chloromercuribenzoate combines with native egg albumin either not at all or much more loosely than it combines with the SH groups of denatured egg albumin or of cysteine.

8. The compound of mercuribenzoate and SH, like the compound of aldehyde and SH and like the SH in native egg albumin, does not give a nitroprusside test or reduce ferricyanide but does reduce iodine.
ENZYMES IN ONTOGENESIS (ORTHOPTERA)
Authors: Bodine Joseph Hall , Carlson Loren D.
Published: May 2004

1. Proteins, when added to activators (sodium oleate. Aerosol) of protyrosinase, greatly decrease the degree of activation.

2. Certain proteins adsorbed on activator micelles are markedly affected by temperature and are rendered more sensitive by ultraviolet light.

3. Ideas are expressed as to the possible nature of activating and inhibiting phenomena especially as they relate to the enzyme tyrosinase.
A NEW METHOD FOR THE STUDY OF DIFFUSION OF BIOLOGICALLY ACTIVE MATERIAL
Authors: Bourdillon Jaques
Published: May 2004

A simple diffusion apparatus has been described in which a layer of solution is allowed to diffuse upward into a layer of solvent. Accurate sampling is performed at various heights and the concentration of the samples is determined.

The method has been illustrated with a determination of the diffusion constant of crystalline catalase, which was found to be 3.1 x 10–7 cm.2/sec. at 4°C. The method should be especially suited to the study of biological substances endowed with specific activity and which cannot be obtained in pure solution.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Abrams Irving , Carr Charles W.
Published: May 2004

1. The electrochemical behavior of membranes prepared from commercial collodion preparations varies widely, some preparations showing very high, other ones very low electrochemical efficiency ("activity").

2. The electrochemical activity of a collodion membrane depends entirely upon impurities of an acidic nature contained in the collodion used for casting the membrane.

3. The active acidic impurities are substantially due to partial oxidation which occurs in the manufacturing process. Sulfuric acid compounds; e.g., acid sulfuric acid esters play only a minor rôle, if any.

4. The electrochemical behavior of collodion membranes in solutions of strong electrolytes is decisively dependent upon the acidic groups built permanently into the collodion surfaces. Preferential ion adsorption plays only a minor, if any, rôle.
MELANOPHORE BANDS AND AREAS DUE TO NERVE CUTTING, IN RELATION TO THE PROTRACTED ACTIVITY OF NERVES
Authors: Parker G. H.
Published: May 2004

1. When appropriate chromatic nerves are cut caudal bands, cephalic areas, and the pelvic fins of the catfish Ameiurus darken. In pale fishes all these areas will sooner or later blanch. By recutting their nerves all such blanched areas will darken again.

2. These observations show that the darkening of caudal bands, areas, and fins on cutting their nerves is not due to paralysis (Brücke), to the obstruction of central influences such as inhibition (Zoond and Eyre), nor to vasomotor disturbances (Hogben), but to activities emanating from the cut itself.

3. The chief agents concerned with the color changes in Ameiurus are three: intermedin from the pituitary gland, acetylcholine from the dispersing nerves (cholinergic fibers), and adrenalin from the concentrating nerves (adrenergic fibers). The first two darken the fish; the third blanches it. In darkening the dispersing nerves appear to initiate the process and to be followed and substantially supplemented by intermedin.

4. Caudal bands blanch by lateral invasion, cephalic areas by lateral invasion and internal disintegration, and pelvic fins by a uniform process of general loss of tint equivalent to internal disintegration.

5. Adrenalin may be carried in such an oil as olive oil and may therefore act as a lipohumor; it is soluble in water and hence may act as a hydrohumor. In lateral invasion (caudal bands, cephalic areas) it probably acts as a lipohumor and in internal disintegration (cephalic areas, pelvic fins) it probably plays the part of a hydrohumor.

6. The duration of the activity of dispersing nerves after they had been cut was tested by means of the oscillograph, by anesthetizing blocks, and by cold-blocks. The nerves of Ameiurus proved to be unsatisfactory for oscillograph tests. An anesthetizing block, magnesium sulfate, is only partly satisfactory. A cold-block, 0°C., is successful to a limited degree.

7. By means of a cold-block it can be shown that dispersing autonomic nerve fibers in Ameiurus can continue in activity for at least 6½ hours. It is not known how much longer they may remain active. So far as the duration of their activity is concerned dispersing nerve fibers in this fish are unlike other types of nerve fibers usually studied.
THE SIMPLEX FLICKER THRESHOLD CONTOUR FOR THE ZEBRA FINCH
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

The flicker response contour has been determined, with equality of light-dark time ratio, for the diurnal bird the Australian zebra finch. This bird has only cones in the retina. The curve of log critical intensity as a function of flash frequency is simplex, a normal probability integral. In this respect it is like that for other vertebrates not exhibiting visual duplexity. The parameters of the curve most closely approach those for the turtle Pseudemys (extrapolated to about the same temperature); it is not improbable that the approximation of these two curves would be less close for other values of the light-time fraction. Some points of interpretive visual theory are discussed in relation to the present measurements.
EFFECTS OF NITROBENZENE AND BENZENE ON VALONIA
Authors: Osterhout W. J. V.
Published: May 2004

The effects of nitrobenzene and of benzene resemble those of guaiacol and of hexylresorcinol. The P.D. changes in a positive direction and then in a negative direction. The latter change may bring the P.D. back to the starting point with guaiacol and hexylresorcinol but with nitrobenzene and benzene this is not always the case.

The positive potential change produced by nitrobenzene and benzene may be antagonized to some extent by ammonia.

Nitrobenzene and benzene raise the electrical resistance and this is antagonized to some extent by ammonia.

The results afford a further illustration of the important fact that the behavior of inorganic ions can be changed by organic substances. The apparent mobility of Na+ is increased and that of K+ decreased by nitrobenzene and benzene (as is also the case with guaiacol and hexylresorcinol).
THE EFFECT OF DETERGENTS ON THE CHLOROPHYLL-PROTEIN COMPOUND OF SPINACH AS STUDIED IN THE ULTRACENTRIFUGE
Authors: Smith Emil L. , Pickels Edward G.
Published: May 2004

1. The chlorophyll-protein compound of the spinach leaf has been studied in the air-driven ultracentrifuge using the Svedberg light-absorption method, and a direct-reading refractive index method.

2. When the untreated extracts are centrifuged at low speeds, the green protein sediments with a purely random spread of particle sizes confirming the fact that the protein is not in true solution.

3. In the presence of digitonin, bile salts, and sodium desoxycholate, the extracts are clarified. These detergents split the chlorophyll from the protein and the protein itself shows a sedimentation constant of 13.5 x 10–13 equivalent to a molecular weight of at least 265,000 as calculated from Stokes' law. This probably represents the minimum size of the protein in native form.

4. Sodium dodecyl sulfate, a detergent which also clarifies the leaf extracts, shows a different behavior. The prosthetic group remains attached to the protein but the protein is split into smaller units. In 0.25 per cent SDS, S20 is 2.6 x 10–13 over a pH range of 5 to 9, although at the acid pH chlorophyll is converted to phaeophytin. In 2.5 per cent SDS, S20 is 1.7 x 10–13 suggesting a further splitting of the protein.

5. No differences in behavior were found for the various chloroplast pigments.
FORMATION OF AUXIN IN YEAST CULTURES
Authors: Robinson True W. , Stier T. J. B.
Published: May 2004

We have found far more auxin in the culture media of bakers' yeast than was obtained by Kögl and Kostermans from the cells themselves. The production of auxin by yeast cells resembles the formation observed in other organisms such as Rhizopus and Rhizobium which also form auxins in their culture media.

The auxin yield was found to increase with the concentration of sucrose and to decrease with the concentration of peptone. An inverse relation with the rate of cell multiplication was observed. Enlarged and elongated cells appeared only in those media which contained considerable amounts of auxin.

The total auxin yield in the various cultures was found to be directly proportional, below pH 5, to the hydrogen ion concentration. Thus, it was proposed that certain growth conditions favor the breakage of the link between auxin and its protein carrier (Skoog and Thimann) 1940) and consequently accelerate the rate of excretion of auxin into the growth medium.
THE INFLUENCE OF ROENTGEN RAYS UPON THE NITROGEN FIXATION BY AZOTOBACTER
Authors: Whelden R. M. , Enzmann E. V. , Haskins C. P.
Published: May 2004

The influence of graded x-ray doses upon nitrogen fixation and respiration by Azotobacter was studied by means of the Warburg method. It was found that nitrogen fixation decreases approximately linearly with increasing x-ray doses. Respiration in contrast is affected only indirectly through some inhibition of cell multiplication. Small doses of x-ray often produce a slight and transient increase in the rate of oxygen uptake.
RECTIFICATION AND INDUCTANCE IN THE SQUID GIANT AXON
Authors: Cole Kenneth S.
Published: May 2004

Previous measurements have shown that the electrical properties of the squid axon membrane are approximately equivalent to those of a circuit containing a capacity shunted by an inductance and a rectifier in series. Selective ion permeability of a membrane separating two electrolytes may be expected to give rise to the rectification. A quasi-crystalline piezoelectric structure of the membrane is a plausible explanation of the inductance. Some approximate calculations of behavior of an axon with these membrane characteristics have been made. Fair agreement is obtained with the observed constant current subthreshold potential and impedance during the foot of the action potential.

In a simple case a formal analogy is found between the calculated membrane potential and the excitability defined by the two factor formulations of excitation. Several excitation phenomena may then be explained semi-quantitatively by further assuming the excitability proportional to the membrane potential.

Some previous measurements and subthreshold potential and excitability observations are not consistent with the circuit considered and indicate that this circuit is only approximately equivalent to the membrane.
INACTIVATION OF PEPSIN BY IODINE
Authors: Herriott Roger M.
Published: May 2004

1. Pepsin solutions were iodinated at pH 5.0–6.0 until 10–20 per cent of the activity was lost and 1/20 (0.7 per cent) of the saturating amount of iodine had been introduced into the protein molecule. After alkaline hydrolysis 65 per cent of the original iodine was accounted for as mono-iodotyrosine although only 42 per cent was isolated as a crystalline product. No evidence was obtained to support the possibility that any group other than tyrosine in pepsin was iodinated.

2. Some of the properties of the crystalline l-mono-iodotyrosine were determined and compared to those of di-iodotyrosine.

3. One iodinated pepsin preparation was crystallized. The crystal form was the same as that of the original pepsin. A solubility curve of the crystals demonstrated that it was very different from pepsin and had nearly constant solubility.
THE OCCURRENCE AND DISTRIBUTION OF ATROPINESTERASE, AND THE SPECIFICITY OF TROPINESTERASES
Authors: Glick David , Glaubach Susi
Published: May 2004

Atropinesterase was found to exist in approximately one out of every four rabbits, and no relation could be observed between the incidence of the enzyme and season, sex, color, age, or weight. The occurrence of the enzyme was also shown to be unrelated to that of cholinesterase.

The distribution of atropinesterase in the blood and organs of rabbits was studied; the animals devoid of the enzyme in their blood contained no demonstrable activity in any of the organ extracts tested.

The presence of atropinesterase in frog liver, and its absence from the serum, has been confirmed. Hydrolysis of homatropine, but not atropine, by guinea pig liver was observed, while the serum was without action on either of the compounds. On this basis the possibility arises that guinea pig liver contains a homatropinesterase enzyme separate from atropinesterase.

It was shown that lack of atropinesterase activity in certain rabbits is not likely to be due to the presence of a naturally occurring inhibitor.

It has been demonstrated that contrary to previous indications neither fresh egg white nor yolk possess atropinesterase activity.

The specificity of tropinesterases was investigated and evidence was presented for the possible existence of two distinct enzymes, cocainesterase and tropacocainesterase.
ANALYTICAL DIFFUSION OF INFLUENZA VIRUS AND MOUSE ENCEPHALOMYELITIS VIRUS
Authors: Bourdillon Jaques
Published: May 2004

Analytical diffusion has been applied to a study of influenza A virus in mouse lung, influenza A virus in the extra-embryonic fluids of the chick, and mouse encephalomyelitis virus in mouse brain.

The results from influenza in mouse lung suggested that about 99 per cent of the infectivity was present in particles 200 mµ in diameter, and 1 per cent in particles 6 mµ in diameter.

The results from influenza in extra-embryonic fluids indicated that the preparation was inhomogeneous and that the smallest virus units were about 6 mµ in diameter.

The results from mouse encephalomyelitis virus indicated that the preparation was also inhomogeneous, with 10 per cent of the infectivity in particles about 15 mµ in diameter.

It has been suggested that in virus preparations normal colloidal particles can act as carriers of much smaller virus units.
PHOTOXIDATION PROCESSES IN PLANTS
Authors: Franck J. , French C. S.
Published: May 2004

1. Photoxidation in leaves is measured by exposing them to light in an atmosphere free from carbon dioxide but containing varied percentages of oxygen.

2. Photoxidation is observed in living leaves as well as in dead ones and in plant juices. Its rate is only slightly enhanced by feeding the leaves with sugar, but the respiration (autoxidation) becomes considerably enlarged during the exposure and the following dark period.

3. The rate of photoxidation rises slower than linearly with light intensity; its dependence upon oxygen pressure has the character of a saturation curve. Oxygen saturation occurs at about 6/10 of an atmosphere of oxygen. A similar dependence on oxygen pressure has been observed by Gaffron for photoxidation in vitro sensitized by chlorophyll adsorbed on proteins and by Warburg for the depression of the saturation rate of photosynthesis.

4. The influence of photoxidation on photosynthesis and the chemical kinetics of photoxidation are discussed.
SOME FACTORS WHICH INFLUENCE THE OXIDATION OF SULFHYDRYL GROUPS
Authors: Anson M. L.
Published: May 2004

1. Cyanide inhibits the oxidation of the SH groups of cysteine and denatured egg albumin by the uric acid reagent.

2. At pH 4.8 cysteine is oxidized by the uric acid reagent and by ferricyanide in the presence but not in the absence of added copper sulfate.

3. In neutral solution, the uric acid reagent oxidizes the SH groups of denatured egg albumin in the presence of urea but not in the presence of alkyl sulfate or in the absence of denaturing agents.

4. Ferricyanide oxidizes the SH groups of neutral denatured egg albumin even in the presence of alkyl sulfate or, if precautions are taken to avoid aggregation, in the absence of denaturing agents.

5. In acid solution, ferricyanide does not oxidize the SH groups of denatured egg albumin completely. The oxidation is more complete, however, in the presence of urea than in the presence of alkyl sulfate, and more complete in the presence of guanidine hydrochloride than in the presence of urea.

6. The uric acid reagent which does not oxidize the SH groups of neutral denatured but unhydrolyzed egg albumin in the absence of denaturing agents does, under the same conditions, oxidize the SH groups of egg albumin partially hydrolyzed by pepsin.

7. At pH 4.8 in alkyl sulfate solution ferricyanide oxidizes the SH groups of digested egg albumin more completely than the SH groups of denatured but undigested egg albumin.
THEORY AND MEASUREMENT OF VISUAL MECHANISMS
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

Flicker response curves (man) obtained with images formed entirely within the fovea are like those secured with lower animals having only one general class of retinal receptors. They are normal probability integrals (F vs. log Im), and the properties of their parameters agree with those for visually simplex animals and for the "cone" portions of contours exhibiting visual duplexity.

By several different procedures, involving experimental modifications of the "cone" curve, the "rod" part of the typical human duplex curve can be obtained free from overlapping by the extrapolated "cone" curve. It then has the probability integral form which the lower segment does not directly exhibit when combined with "cone" effects.

These results are discussed with reference to the statistical nature of the fundamental form of the flicker contour and to the interpretation of duplex curves produced by the neural integration of two independently modifiable groups of sensory effects.
THE WAVELENGTH SENSITIVITY FUNCTION FOR THE ZEBRA FINCH
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

With lights of different spectral compositions filtered from a white, the flicker response contours for the zebra finch are found to exhibit the same general kind of relationship between flicker excitation and wavelength as is found in the case of man ("cone" contours), with the same filters. The flicker contours for the zebra finch are simplex; the retina contains no rods. On a relative energy scale, with a flash cycle of fixed light-time percentage (10 per cent) the curve for yellow almost coincides with that for the white, the curve for red lies at much higher intensities, and the curves for blue-green and violet fall below that for the white by amounts increasing in that order. The maxima to which the curves rise and the slope constants are very nearly the same for all the spectral regions. For the bird the blue was a little less efficient, the green a little more efficient, and the red very much less efficient than in the case of man. It was deduced that in the retina of this diurnal bird the number of red oil globules should be comparatively small and that most of the globules should be greenish yellow. This was confirmed by direct examination.
AN ELECTROPHORETIC STUDY OF MIXTURES OF OVALBUMIN AND YEAST NUCLEIC ACID
Authors: Longsworth Lewis G. , MacInnes D. A.
Published: May 2004

Electrophoretic patterns of mixtures of ovalbumin and yeast nucleic acid indicate that the constituents migrate independently of each other in buffer solutions of 0.1 ionic strength and at pH values somewhat higher than the isoelectric point of the protein. In the isoelectric region, however, the patterns from the two sides of the channel exhibit asymmetries that can be explained by assuming the existence in the mixture of appreciable concentrations of a reversibly dissociable complex between the components. Formation of this complex is favored by increasing concentrations of the components and decreasing ionic strength. At pH values below the isoelectric point partial precipitation of the complex occurs.

The patterns obtained from each side of the channel in the electrophoresis of a mixture of two components, which form a dissociable complex, indicate only two boundaries, aside from the δ and ϵ effects. One of these is a normal boundary whose displacement is proportional to the mobility of a component that has separated from the mixture. In the other boundary, however, dissociation of the complex occurs and consequently the displacement of this boundary corresponds to the mobility of neither component nor to that of the complex. Moreover, the areas under the refractive index gradient curves are not proportional to the stoichiometric concentrations of the components. However, equations are developed with the aid of which an electrophoretic analysis of the mixture is possible. This analysis requires the use of data from the patterns of both channels.
A CYCLOSCOPIC STUDY OF THE HUMAN ELECTROENCEPHALOGRAM
Authors: Cohn Robert
Published: May 2004

Cycloscopic analyses of a series of electroencephalograms obtained from a mixed group of individuals, clinically classified as normal, schizophrenic, and "frank" epileptic, show the following characteristics:

1. A rather closely regulated potential oscillation which remains predominant throughout the sample of record under study.

2. Associated with this dominant cycle other definite anharmonic cycles are clearly evident. These associated cycles may operate in intermittent sequences or simultaneously with the dominant cycle.

Subjects with "atypical" epilepsy show an apparently characteristic spread of low intensity cycles.
VISUAL ACUITY AND ILLUMINATION IN DIFFERENT SPECTRAL REGIONS
Authors: Shlaer Simon , Smith Emil L. , Chase Aurin M.
Published: May 2004

The relation between visual acuity and illumination was measured in red and blue light, using a broken circle or C and a grating as test objects.

The red light data fall on single continuous curves representing pure cone vision. The blue light data fall on two distinct curves with a transition at about 0.03 photons. Values below this intensity represent pure rod vision. Those immediately above represent the cooperative activity of rods and cones, and yield higher visual acuities than either. Pure cone vision in this intensity region is given by central fixation (C test object). All the rest of the values above this transition region represent pure cone vision. In blue light the rod data with the C lie about 1.5 log units lower on the intensity axis (cone scale) than they do in white light, while with the grating they lie about 1.0 log unit lower than in white light.

Both the pure rod and cone data with the C test object are precisely described by one form of the stationary state equation. With the grating test object and a non-limiting pupil, the pure rod and cone data are described by another form of the same equation in which the curve is half as steep. The introduction of a small pupil, which limits maximum visual acuity, makes the relation between visual acuity and illumination appear steeper.

Determinations of maximum visual acuities under a variety of conditions show that for the grating the pupil has to be larger, the longer the wavelength of the light, in order for the pupil not to be the limiting factor.

Similar measurements with the C show that when intensity discrimination at the retina is experimentally made the limiting factor in resolution, visual acuity is improved by conditions designed to increase image contrast. However, intensity discrimination cannot be the limiting factor for the ordinary test object resolution because the conditions designed to improve image contrast do not improve maximum visual acuity, while those which reduce image contrast do not produce proportional reductions of visual acuity.
SOME PROPERTIES OF CRYSTALLINE GUINEA PIG HEMOGLOBIN
Authors: Granick Sam
Published: May 2004

1. Guinea pig hemoglobin crystals are shown to be readily permeable to ferricyanide and hydrosulfite, indicating the presence of interstices between the protein molecules of the crystal.

2. The assumptions of closest hexagonal packing and of spherical molecules of HbO2 lead to a crystal lattice having interstices between the molecules which represent 25 per cent by volume of the crystal. These spaces would be just large enough at their narrowest junctures to permit ferricyanide ions to diffuse through them. If these spaces were filled with water, then 20 per cent by weight of the crystals would be water.

3. The hemes are on the surface of the globin and are arranged facing the interstices between the molecules of the lattice.

4. The binding of O2 in HbO2 is stronger in the crystal lattice than in solution.

5. Hydrogen, activated with colloidal palladium, will not reduce ferrihemoglobin except in the presence of a redox dye.

6. In the reduction of O2 by activated hydrogen, H2O2 can be demonstrated by the formation of the H2O2-ferrihemoglobin spectrum.
THE PRESENCE OF AN ENDOGENOUS RESPIRATION IN THE AUTOTROPHIC BACTERIA
Authors: Vogler K. G.
Published: May 2004

It is shown that there exists in the autotrophic bacterium Thiobacillus thiooxidans a measurable oxygen uptake in the absence of the specific nutrient (sulfur). This respiration is shown to be due to the utilization of organic materials which must have been previously synthesized by the chemosynthetic process, providing evidence that autotrophic bacteria contain a dissimilatory process which involves the breakdown of organic materials and furnishes energy for the maintenance of the cell during periods in which the specific nutrient is absent. This is entirely in accord with the work of Bömeke (1939), who provided similar types of proof for Nitrosomonas and Nitrobacter. One may conclude, therefore, that autotrophic bacteria possess an endogenous respiration which involves the utilization of previously synthesized organic materials.
STUDIES ON CELL METABOLISM AND CELL DIVISION
Authors: Hutchens John O. , Keltch A. K. , Krahl M. E. , Clowes G. H. A.
Published: May 2004

1. Under the present conditions of experiment, Arbacia eggs were found to contain an average of 110 mg. of acid-hydrolyzable carbohydrate (calculated as glucose) per gm. of egg protein. This carbohydrate was almost all in the egg proper, little or none being found in the jelly.

To permit conversion of the data to other bases of reference the relation of nitrogen content to wet and dry weight and to egg number were determined. The eggs were found to contain 23.9 per cent solids, 0.10 mg. nitrogen per mg. dry weight, and 5.93 mg. nitrogen per 106 cells. From these results, about 7 per cent of the egg dry weight is acid-hydrolyzable carbohydrate and about 65 per cent is protein.

2. Approximately one-half of the total acid-hydrolyzable carbohydrate was isolated in the form of an alkali-stable, alcohol-precipitable carbohydrate. This substance gave a typical glycogen color test with iodine, yielded glucose on acid hydrolysis, and had, within the limits of experimental error, the same optical rotation as glycogen from other animal sources. Since known amounts of glycogen were completely recovered when carried through the isolation process, the nature of one-half of the acid-hydrolyzable carbohydrate of Arbacia eggs remains undetermined.

3. In order to gain some estimate of the extent to which Arbacia eggs utilize their total carbohydrate for development, determinations of the oxygen consumption, respiratory quotient, carbohydrate consumption, lactic acid production, and ammonia production were made. While all samples of eggs were found to utilize carbohydrate from the 15th to the 24th hours of development at 20°C., certain samples of eggs consumed little or no carbohydrate from the 1st to the 6th hours, the period during which cell division proceeds most rapidly. In a number of instances where carbohydrate breakdown was lacking, a substantial proportion of the oxygen consumption could be accounted for on the basis of processes involving oxidation of protein or protein breakdown products.
ELECTRIC IMPEDANCE OF THE FROG EGG
Authors: Cole Kenneth S. , Guttman Rita M.
Published: May 2004

Electrical impedance measurements were made upon unfertilized and fertilized eggs of the leopard frog, Rana pipiens, over a frequency range of 0.05 to 10 kc. Average values of 170 ohm cm.2 were obtained for the plasma membrane resistance of the egg, 2.0 µf/cm.2 for the plasma membrane capacity, 86° for the phase angle of the membrane, and 570 ohm cm. for the specific resistance of the interior. These values did not change upon fertilization. No spontaneous rhythmical impedance changes such as have been found by Hubbard and Rothschild in the trout egg were found in frog eggs.