bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF SODIUM CHLORIDE ON PHAGE FORMATION BY STAPHYLOCOCCI AT ELEVATED TEMPERATURES
Authors: Fong J. , Krueger A. P. 
Published: May 2004

In experiments with the K strain of Staphylococcus aureus and the K race of bacteriophage suspended in tryptose phosphate broth and maintained at 42°C. it was found that the presence of 1 M NaCl produced certain drastic changes in the relationship between the host cells and the infecting virus:
1. Staphylococci grown at 42°C. in plain broth or in NaCl-broth are "activated," i.e. when growth is stopped by lowering the temperature to 5°C. and phage is added, the activity titre immediately displays a rise of 15- to 16-fold.
2. 1 M NaCl tends to prevent the sorption of phage by cocci and this effect is more pronounced at 42°C. than at 5°C. When the activation test is conducted at 5°C. (the usual temperature) most of the phage is picked up by the cells and the described increase in activity titre follows. If the test takes place at 42°C. there is little sorption and correspondingly little rise in phage titre.
3. Mixtures of staphylococci and phage incubated at 42°C. in NaCl-broth fail to produce phage; the final plaque and activity titres are identical with the initial titres. Here, also, the influence of 1 M NaCl in preventing contact of phage with cocci appears to account for the results.
4. Similar mixtures held at 42°C. in plain broth exhibit a drop of about 60 per cent in activity and plaque titres. The loss of phage may be due to adsorption on dead cells accumulating in the suspension or to the thermolability of the bacterium-phage complex, or to both.
THE RELATIONS OF THE PLASMA MEMBRANE, VITELLINE MEMBRANE, AND JELLY IN THE EGG OF NEREIS LIMBATA
Authors: Costello Donald P. 
Published: May 2004

1. The problem of the relation of the plasma membrane to the extraneous coats and cortex of the Nereis egg is discussed in the light of the observations of Lillie, Chambers, and Novikoff.
2. Evidence obtained from experiments with the centrifuge, and by treating eggs with alkaline sodium chloride, indicates that the plasma membrane of the unfertilized egg is external to the jelly precursor granules of the cortex.
3. Experiments with alkaline sodium chloride indicate that the perivitelline space of the fertilized egg is extraovular after jelly extrusion is complete.
4. The cortical behavior (membrane elevation) of the Nereis egg in alkaline sodium chloride and the cortical response (jelly extrusion) following activation of the egg in normal fertilization or parthenogenesis are attributed largely to the properties of the jelly, and presumably, to its reactions with calcium and hydroxyl ions.
THE TONICITY-VOLUME RELATIONS FOR HUMAN RED CELLS SUBJECTED TO THE ACTION OF HEAT, WITH SPECIAL REFERENCE TO PROLYTIC K LOSS
Authors: Ponder Eric 
Published: May 2004

1. The volume-tonicity relations for human red cells exposed to a temperature of 48°C. for 2 minutes remain the same as those for unheated human red cells. The heated systems show lysis in higher tonicities than the unheated systems do; this is probably largely due to fragmentation with its effect on the geometry of the situation, as suggested by Ham, Shen, Fleming and Castle. When the cells are heated to 48°C. for longer times, the amount of fragmentation becomes considerable, but the volume-tonicity relation remains the same as before; the properties which are usually referred to as the osmotic properties of the red cell are accordingly not necessarily dependent on the integrity of the cell as a unit.
2. Heating to 52°C. for 2 minutes profoundly modifies the volume-tonicity relation, very little swelling now occurring even in tonicities as low as 0.6. This is partly accounted for by the large K losses and K-Na exchanges which occur and which become greater as the tonicity is reduced and as the temperature is increased. Fragmentation and hemolysis also increase, the latter out of proportion to the expected effects of the former. Direct effects of heat on the cohesion of the red cell ultrastructure are probably involved.
STUDIES ON THE MECHANISM OF ACTION OF IONIZING RADIATIONS
Authors: Barron E. S. Guzman , Dickman Sherman , Muntz John A. , Singer Thomas P. 
Published: May 2004

Dilute solutions of sulfhydryl enzymes (phosphoglyceraldehyde dehydrogenase, adenosinetriphosphatase, succinoxidase) showed reduced activity on irradiation by small amounts of x-rays. When the inhibition was partial the enzyme was reactivated on addition of glutathione. When the inhibition was more complete, reactivation was only partial. These observations are interpreted as being due to oxidation of the —SH groups of the protein by the products of water irradiation, the radicals OH and O2H, and H2O2 and atomic oxygen. The irreversible inhibition which occurs when the dose of x-rays is increased is attributed to protein denaturation.
Inhibition of the non-sulfhydryl enzymes trypsin, catalase, and ribonuclease, which required larger amounts of x-rays, is attributed to protein denaturation.
These experiments are further evidence that inhibition of enzymes by ionizing radiations is due to the indirect action of the products of irradiated water rather than to direct ionization of the enzyme through collision with the ionizing radiation.
THE STABILITY OF BACTERIAL VIRUSES IN SOLUTIONS OF SALTS
Authors: Adams Mark H. 
Published: May 2004

1. The seven bacterial viruses of the T group, active against E. coli, are much more rapidly inactivated by heat when suspended in 0.1 N solutions of sodium salts than when suspended in broth.
2. The kinetics of this inactivation whether in salt solutions or in broth are those of a first order reaction.
3. The rate of inactivation of phage T5 in 0.1 N NaCl at 37°C. can be greatly decreased by the addition of 10–8 M concentrations of such divalent cations as Ca, Mg, Ba, Sr, Mn, Co, Ni, Zn, Cd, and Cu.
4. An increase in the cation concentration in the suspending medium results in an increase in the stability of phage T5 to the inactivating effects of temperature.
5. The hypothesis is proposed that the increase in stability of phage T5 in the presence of various cations is the result of complex formation between the phage and the metal ion.
STUDIES ON THE MECHANISM OF ACTION OF IONIZING RADIATIONS
Authors: Barron E. S. Guzman , Dickman Sherman 
Published: May 2004

The activity of crystalline phosphoglyceraldehyde dehydrogenase and urease was decreased when dilute solutions of these sulfhydryl enzymes were irradiated with small doses of alpha rays from Po, beta rays from Si89, and gamma rays from Ra. Partial reactivation of the enzyme by addition of glutathione was obtained after inhibition with alpha rays. Evidence that these inhibitions are due to oxidation of the —SH groups of the enzymes was given by the irradiation of the mercury-mercaptide urease with gamma rays. This irradiated complex was completely reactivated by glutathione as was the non-irradiated enzyme. The ionic efficiency of all these ionizing radiations on inhibition of phosphoglyceraldehyde dehydrogenase was similar (ionic yield around 1).
The sulfhydryl groups of crystalline phosphoglyceraldehyde dehydrogenase were titrated by enzyme activity measurements and by ferricyanide oxidation.
CORRELATION OF THE AQUARIUM GOLDFISH TOXICITIES OF SOME PHENOLS, QUINONES, AND OTHER BENZENE DERIVATIVES WITH THEIR INHIBITION OF AUTOOXIDATIVE REACTIONS
Authors: Sollmann Torald 
Published: May 2004

Hydroquinone when added to the aquarium water was found to be about a hundred times more toxic than phenol, to goldfish (and to Daphnia magna), but is only about twice as toxic when injected into fish or mammals. Tertiarybutyl catechol shows a similar high toxicity in the aquarium, while the toxicity of catechol, resorcinol, and pyrogallol approaches more closely that of phenol.
As the substances of high aquarium toxicity are known to inhibit many oxidative and polymerizing autocatalytic "chain reactions," rank correlations were tabulated between the recorded inhibitory potency of various substances in these processes, and their aquarium toxicity for goldfish.
The correlation between aquarium fish toxicity and electric oxidation potential (P 0.09) is more than suggestive, and becomes still more so if explainable discrepancies are excluded. Antioxidant fat stabilizers show suggestive correlation with fish toxicity (0.20), and better with electric oxidation potential (0.10). The photographic reduction potential gives suggestive correlation with fish toxicity (0.20) and somewhat better with the oxidation potential (0.15). The gasoline induction period correlation is more than suggestive with the oxidation potential (0.099), but rather poor for fish toxicity (0.265). The rubber anti-aging potency gives only poor correlation (0.39) with fish toxicity. The reasons for these divergencies are not clear; they may perhaps be connected with the solvent properties of the substrate. As an example, Lea (p. 175) cites that 0.01 per cent of maleic acid prevents rancidity of fats, but is rendered ineffective by the presence of water.
Taken by themselves, no one of the P values is entirely convincing of the relationships stressed in this paper. However, the consistent finding of relatively small values of P lends considerable weight to the hypothesis that these chemicals act in a related manner; and that the chemical activity of a substance may furnish useful suggestions of its biologic potency, perhaps more so than the chemical constitution as such. The aquarium toxicity, for goldfish is a convenient means of classifying the biologic potency.
OXYGEN TENSION MEASUREMENT BY A METHOD OF TIME SELECTION USING THE STATIC PLATINUM ELECTRODE WITH ALTERNATING POTENTIAL
Authors: Olson Rodney A. , Brackett Frederick S. , Crickard Robert G. 
Published: May 2004

1. The possibility of obtaining sustained and reproducible results in the analysis of dissolved oxygen with simple platinum electrodes by means of the application of a periodic potential pattern was explored over a wide range of frequencies and with a variety of wave forms.
2. Satisfactory results were obtained by the application in the frequency range of 5 to 10 C.P.M. of a square wave consisting of a positive and a negative pulse with interposed shorting periods and observing the current flowing at the end of each successive negative pulse. This was found to be linearly proportional to O2 concentration for a pulse duration of the order of 1 second when the RC constant of the circuit was sufficiently small.
3. An instrument was developed to provide the required wave form and record the terminal currents of the negative pulses. The instrument provides either for recording of current voltage curves (polarograms) or for continuous recording at a fixed voltage of diffusion limited current values.
4. Typical measurements of oxygen uptake with yeast suspensions illustrate the application of the technique to problems requiring frequent determinations during short intervals.
5. Applications of this technique to biological and other problems are indicated with its limitations.
QUANTITATIVE CYTOCHEMICAL DETERMINATION OF DESOXYRIBONUCLEIC ACID WITH THE FEULGEN NUCLEAL REACTION
Authors: Ris Hans , Mirsky A. E. 
Published: May 2004

The possibility of using the Feulgen nucleal reaction for a quantitative cytochemical estimation of desoxyribonucleic acid (DNA) was investigated. The intensity of the reaction in nuclei was determined by absorption measurements with the microscope. The accuracy of such measurements was tested by comparison with measurements on the same material with a Beckman spectrophotometer. The values obtained with the microscope agreed within a few per cent with those obtained with the Beckman spectrophotometer. Furthermore, the errors introduced by uneven distribution of absorbing material, by variations in the numerical aperture of the system, and by variation in the area used on the phototube were investigated empirically.
The following variables were studied with regard to their effect on the intensity of the Feulgen reaction: type of fixation, time of hydrolysis after acetic acid-alcohol and formalin fixation, time of staining in leucobasic fuchsin, method of preparation of leucobasic fuchsin.
The intensity of the Feulgen reaction in liver and erythrocyte nuclei of various vertebrates, fixed in acetic acid-alcohol, was then compared with the DNA content of these nuclei as determined by chemical analysis on a known number of nuclei. The intensity of the reaction was found to be proportional to the DNA content of the nuclei, if nuclei of similar structure and DNA concentration were compared. In nuclei of different structure and DNA concentration (i.e. liver and erythrocyte nuclei), fixed in acetic acid-alcohol, the intensity of the Feulgen reaction was, however, not proportional to the DNA content. This difficulty was overcome by isolating nuclei in sucrose and by fixing them in formalin. Uniform distribution of DNA and therefore uniform coloring after the Feulgen reaction were thus obtained. In such nuclei with uniform distribution of absorbing material the Feulgen reaction was found to be proportional to the DNA content of nuclei, even if they differed greatly in their DNA concentration.
The Feulgen nucleal reaction is not quantitative in an absolute sense. For absolute determinations nuclei of known DNA content must be treated together with the unknown material to serve as standard.
From these data it therefore appears possible to determine cytochemically relative amounts of DNA in cellular structures by measuring their absorption after treatment with the Feulgen nucleal reaction.
POST-TETANIC POTENTIATION OF RESPONSE IN MONOSYNAPTIC REFLEX PATHWAYS OF THE SPINAL CORD
Authors: Lloyd David P. C. 
Published: May 2004

Following tetanic afferent stimulation of a monosynaptic reflex pathway, the transmission through that pathway of isolated reflex volleys is enhanced for some minutes. Post-tetanic potentiation is comparable in the monosynaptic reflex arcs of flexor and extensor muscles. The facilitator and inhibitor actions of monosynaptic reflex afferent fibers, as well as the transmitter action, are potentiated following tetanization. Little post-tetanic change attends reflex transmission through plurisynaptic reflex arcs.
Various tests for excitability change made independently of the tetanized afferent fibers reveal none or a slight depression. Hence the potentiating influence of a tetanus is limited to subsequent action on the part of the recently tetanized fibers themselves. Increase in the size of the individual impulses comprising an afferent volley such as might occur during positive after-potential, would accommodate the requirement for a limited process and provide for increased synaptic action. The proposed association between post-tetanic potentiation and positive after-potential (i.e. hyperpolarization) is supported by the following lines of evidence:—
1. Changes in intensity and duration of potentiation with change in frequency and duration of tetanic stimulation are characteristic of, and parallel to, the changes of positive after-potential in similar circumstances.
2. Afferent impulses are increased following a tetanus, and in a fashion that parallels the course of monosynaptic reflex potentiation.
Post-tetanic potentiation, as here described, and after-discharge, whatever may be its mechanism, are unrelated phenomena.
HIGHER PERMEABILITY FOR WATER THAN FOR ETHYL ALCOHOL IN NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

If we apply water at one end of a Nitella cell, A, and place at the other end, B, a solution of a substance which does not penetrate, such as sucrose, water enters the cell at A, passes along inside the cell, and escapes at B. But if in place of sucrose we use a substance which penetrates such as ethyl alcohol the flow of water is lessened and this fact makes it possible to measure the amount of alcohol which enters. (An increase in the size of cells placed in solutions of alcohol does not necessarily indicate that the number of mols of alcohol entering is greater than the number of mols of water leaving the cell.)
The permeability for water is more than 18 times as great as for ethyl alcohol. The behavior of the 2 substances was compared in the same individual cell with a driving force which at the start was the same for both substances. The number of mols entering per second per cm.2 of surface with a driving force of 1 atmosphere at 25°C. is 0.772 (10–6) for water and 0.042 (10–6) for ethyl alcohol.
The experiments indicate that the non-aqueous substance at the surface of the protoplasm has a higher partition coefficient for water than for ethyl alcohol, although the protoplasmic surface is composed of materials not miscible with water.
TIME RELATIONSHIPS IN THE CLEAVAGE OF THE NORMAL FERTILIZED EGG OF ARBACIA PUNCTULATA
Authors: Blum Harold F. , Price Judith P. 
Published: May 2004

Quantitative data are presented indicating the extent of variability in the time of cleavage of normal fertilized eggs of Arbacia punctulata.
It is a pleasure to acknowledge the valuable suggestions and criticisms of Professor Arthur K. Parpart during the course of the experiments described in this and the preceding paper, and those of Professor Douglas A. Marsland and Professor M. J. Kopac at the final manuscript stage.
TISSUE CULTURE STUDIES
Authors: Hull Wayne , Kirk Paul L. 
Published: May 2004

Growing cultures are shown to incorporate more radioactive phosphorus into ribo- and desoxyribonucleic acid than non-growing cultures.
Strong indications are found that the incorporation of inorganic phosphorus into desoxyribonucleic acid parallels the mitotic coefficient and serves as a sensitive index of synthesis of new cells.
There are indications that the phosphorus compounds from which the DNA molecule was synthesized were in equilibrium with the inorganic phosphorus of the medium.
The effect of the implant upon growth of new cells and the assay of growth is discussed. Metabolic turnover was increased in adequate medium.
CRYSTALLINE DESOXYRIBONUCLEASE
Authors: Kunitz M. 
Published: May 2004

A crystalline enzyme capable of digesting thymus nucleic acid (desoxyribonucleic acid) has been isolated from fresh beef pancreas. The enzyme called "desoxyribonuclease" is a protein of the albumin type. Its molecular weight is about 60,000 and its isoelectric point is near pH 5.0. It contains about 8 per cent tyrosine and 2 per cent tryptophane. It is readily denatured by heat. The denaturation is reversible if heated in dilute acid at pH about 3.0.
The digestion of thymus nucleic acid by crystalline desoxyribonuclease is accompanied by a gradual increase in the specific absorption of ultraviolet light by the acid. The spectrophotometric measurement of the rate of increase in the light absorption can be conveniently used as a general method for estimating desoxyribonuclease activity.
Details are given of the method for isolation of crystalline desoxyribonuclease and of the spectrophotometric procedure for the measurement of desoxyribonuclease activity.
CRYSTALLINE DESOXYRIBONUCLEASE
Authors: Kunitz M. 
Published: May 2004

A study was made of the enzymatic properties of crystalline desoxyribonuclease. The general effect of the crystalline enzyme on its specific substrate, thymus nucleic acid, was found to be essentially the same as described by previous workers for the digestive action of crude preparations of the enzyme. The digestive action consists mainly in splitting thymus nucleic acid into fragments approaching the size of tetranucleotides. The digested nucleic acid is diffusible through collodion or cellophane membranes and is non-precipitable with strong acid, alcohol, or proteins. The digestion of thymus nucleic acid by desoxyribonuclease is accompanied by the liberation of one atom equivalent of free acid per four atoms of nucleic acid phosphorus.
Crystalline desoxyribonuclease acts very slowly, if at all, in the absence of magnesium (or manganese) ions. The optimal concentration of magnesium ion required increases with the increase in concentration of the substrate but is independent of the enzyme concentration. The optimal pH range for the action of crystalline desoxyribonuclease is 6.0 to 7.0.
A study was made of the kinetics of the digestion of thymus nucleic acid as manifested mainly by the gradual formation of acid-soluble split products. At low concentrations of nucleic acid, the process approximates closely a reaction of the first order, the unimolecular constant being independent of the concentration of desoxyribonuclease in the digestion mixture. At relatively higher concentrations of substrate, however, the initial rate of reaction decreases rapidly with the increase in concentration of substrate, and the reaction as a whole is represented by non-symmetric S-shaped curves apparently too complicated for a simple rational interpretation.
PHOTOSYNTHETIC ACTION SPECTRA OF MARINE ALGAE
Authors: Haxo F. T. , Blinks L. R. 
Published: May 2004

A polarographic oxygen determination, with tissue in direct contact with a stationary platinum electrode, has been used to measure the photosynthetic response of marine algae. These were exposed to monochromatic light, of equal energy, at some 35 points through the visible spectrum (derived from a monochromator). Ulva and Monostroma (green algae) show action spectra which correspond very closely to their absorption spectra. Coilodesme (a brown alga) shows almost as good correspondence, including the spectral region absorbed by the carotenoid, fucoxanthin. In green and brown algae, light absorbed by both chlorophyll and carotenoids seems photosynthetically effective, although some inactive absorption by carotenoids is indicated.
Action spectra for a wide variety of red algae, however, show marked deviations from their corresponding absorption spectra. The photosynthetic rates are high in the spectral regions absorbed by the water-soluble "phycobilin" pigments (phycoerythrin and phycocyanin), while the light absorbed by chlorophyll and carotenoids is poorly utilized for oxygen production. In red algae containing chiefly phycoerythrin, the action spectrum closely resembles that of the water-extracted pigment, with peaks corresponding to its absorption maxima (495, 540, and 565 mµ). Such algae include Delesseria, Schizymenia, and Porphyrella. In the genus Porphyra, there is a series P. nereocystis, P. naiadum, and P. perforata, with increasingly more phycocyanin and less phycoerythrin: the action spectra reflect this, with increasing activity in the orange-red region (600 to 640 mµ) where phycocyanin absorbs.
In all these red algae, photosynthesis is almost minimal at 435 mµ and 675 mµ, where chlorophyll shows maximum absorption. Although the chlorophylls (and carotenoids) are present in quantities comparable to the green algae, their function is apparently not that of a primary light absorber; this role is taken over by the phycobilins. In this respect the red algae (Rhodophyta) appear unique among photosynthetic plants.
ACTION OF NITRO- AND HALOPHENOLS UPON OXYGEN CONSUMPTION AND PHOSPHORYLATION BY A CELL-FREE PARTICULATE SYSTEM FROM ARBACIA EGGS
Authors: Clowes G. H. A. , Keltch A. K. , Strittmatter C. F. , Walters C. P. 
Published: May 2004

1. The ability of 4,6-dinitrocresol and eight other substituted phenols to stimulate oxygen uptake and inhibit phosphorylation by a cell-free particulate system from unfertilized Arbacia eggs has been determined.
Five of those agents can produce both stimulation of oxygen consumption and inhibition of phosphorylation; one inhibits both oxygen consumption and phosphorylation; and two have no effect on either oxygen consumption or phosphorylation.
In every case the effects of these substituted phenols upon the cell-free particulate systems parallel those upon oxygen consumption and cleavage in the intact fertilized Arbacia eggs.
2. The data suggest that energy for cleavage of the Arbacia egg is provided at least in part by oxidative phosphorylation and that substituted phenols may block cleavage by interfering with generation and transfer of high-energy phosphate groups.