bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
STUDIES ON THE PHYSIOLOGICAL BASES OF MORPHOGENESIS IN FUNGI
Authors: Nickerson Walter J. , Edwards George A.
Published: May 2004

The interconversions of mycelial and yeast-like forms (M ⇌ Y) in Blastomyces dermatitidis and in Blastomyces brasiliensis are characterized as examples of thermal dimorphism since the phenomena are apparently dependent only on the temperature of incubation of these two species. The change in morphology consequent upon Y → M conversion is considered to result from the selective inhibition of cell division, without the simultaneous inhibition of growth. Such selective inhibition is viewed in a wider context as an example of the differential operation of the physicochemical apparatus of the cell in the control of form development by an organism. To analyze this differential operation, which is here dependent only on temperature, we have studied the effect of temperature on oxygen consumption by each of the dimorphic forms. In the absence of external substrate the yeast forms consume 5 to 6 times more oxygen per unit dry weight than do the M forms.The Y forms exhibit an exogenous oxidation of acetate and of glucose, as well as an oxidative assimilation of these substrates, whereas the M forms exhibit no exogenous metabolism in either a resting or starved condition. A study of the effect of a wide range of temperatures on oxygen consumption by the M forms indicates the operation of two rate-limiting processes: (a) one with an activation energy of 13,250 calories/gm. molecule over the range 5–30°, and (b) reversible enzyme inactivation; the latter process assuming importance in the higher temperature range. On abrupt, large changes in temperature the balance between these two rate-limiting reactions (which it is suggested characterizes the steady state) is apparently disrupted as a result of a lag in the assumption of a rate of reversible enzyme inactivation characteristic of the new temperature. This disruption of balance is evidenced in overshoot phenomena. The effect of an analogous disruption of balance, and of increasing enzymic inactivation; on a competition between enzyme systems, competing for substrate for cell elongation and for cell division, is considered in explanation of the observed dependence of the cell division mechanism on the maintenance of an elevated temperature.
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.
STUDIES ON THE RIGOR RESULTING FROM THE THAWING OF FROZEN FROG SARTORIUS MUSCLE
Authors: Perry S. V.
Published: May 2004

1. The rigor which takes place when completely frozen frog sartorius muscle is thawed ("thaw rigor"), is accompanied by a decrease in length of 70 per cent and a loss in weight of 35 per cent, whether the muscle is frozen in the resting or the exhausted condition, or during isometric tetanus. Muscle tetanized to maximal shortening shows a loss in weight of 25 per cent on thawing.

2. A load of 8 gm. is sufficient to prevent the decrease in length on thawing, but after its removal the muscle will shorten almost to the normal extent.

3. Inhibitors such as azide, cyanide, 2:4 dinitrophenol, p-chloromercuribenzoate, Cu, and hydrogen peroxide, when used for periods not exceeding 1 hour, have little effect on the shortening; although in some cases these poisons render the muscle inexcitable.

4. Muscles poisoned with iodoacetic acid and stimulated to exhaustion, or maintained at fixed length in nitrogen, show little or no shortening on thawing. ATP can produce shortening in the muscles in which it has been prevented.

5. The phenomenon is considered to be due to an in situ synaeresis of the actomyosin of the myofibrils. As a result of the disorganisation of the muscle protoplasm produced by the freezing and subsequent thawing, the ATP, which must be bound or localized in the resting muscle, can act on the myofibril in a similar manner to its in vitro effect on the actomyosin thread.
THE CYTOCHROME SYSTEM IN THE CECROPIA SILKWORM, WITH SPECIAL REFERENCE TO THE PROPERTIES OF A NEW COMPONENT
Authors: Sanborn Richard C. , William Carroll M.
Published: May 2004

1. In the majority of tissues in the cecropia silkworm, cytochromes b and c are apparently absent, being replaced by a hitherto undescribed component which we have tentatively termed cytochrome x.

2. Spectroscopically, the new cytochrome is characterized in the reduced state by a broad and indivisible absorption band extending from 551 to 562 mµ.

3. The enzyme can be demonstrated only in the larval stage of the insect and undergoes breakdown prior to pupation. It occurs in highest concentration in the walls of the larval midgut and resists extraction, being apparently bound to subcellular particles.

4. Evidence is presented, based on spectroscopic and manometric studies in the presence of various substrates and inhibitors, that cytochrome x is a single component which mimics certain of the properties of cytochromes b and c and of succinic dehydrogenase.

5. Detailed studies served to differentiate cytochrome x from the cytochromes b1 and b2 which it resembles spectroscopically.

6. On the basis of spectroscopic studies at the temperature of liquid air, it is concluded that cytochrome x closely resembles, and may be identical with, the component which Keilin has recently described as cytochrome e.
ENZYMATIC HYDROLYSIS OF SOLUBLE CELLULOSE DERIVATIVES AS MEASURED BY CHANGES IN VISCOSITY
Authors: Levinson Hillel S. , Reese Elwyn T.
Published: May 2004

Observation of changes in fluidity is presented as a method for following the enzymatic hydrolysis of soluble cellulose derivatives. The activity of different cell-free enzyme preparations may be compared by this method, providing certain precautions are observed.

In general, results obtained by use of the fluidity method are similar to those obtained using the reducing sugar technique, indicating that the same enzyme system is measured by the two methods.

Changes in the DP of the substratum may be followed within certain limits of molecular size. Results indicate that a random splitting of CMC occurs during enzymatic hydrolysis, with a concomitant decrease in intrinsic viscosity and an increase in reducing sugars.

Certain inadequacies of the cellulose-cellobiose-glucose theory, together with more recent findings, have led to the postulation of an alternate explanation of the mechanism of cellulose hydrolysis.
ACCUMULATION OF POTASSIUM BY HUMAN RED CELLS
Authors: Ponder Eric
Published: May 2004

1. A method is described for measuring the accumulation of K at 37°C. by washed human red cells in glucose-containing systems in which the pH is kept constant, the K content of the cells being compared with that of the cells of systems which contain no added glucose but which are otherwise treated similarly.

2. In systems containing added glucose, the accumulation of K begins shortly after the cells have been warmed to 37°C., proceeds to a maximum which is reached after about 10 hours, and then falls exponentially. The maximum rate of accumulation is found during the first 3 hours. In systems which contain no added glucose, the K content of the cells appears to decrease exponentially with time for about 18 to 24 hours; thereafter the K content of the cells may decrease rapidly and the systems may show considerable hemolysis. Sometimes a small accumulation effect is observed during the first 2 to 3 hours; this may be the result of the washed cells not having been completely freed of glucose.

3. The accumulation process proceeds at its maximum rate at pH 7.4 to 7.6, which is also the pH at which the K loss from the red cells is at a minimum in systems containing no added glucose.

4. When red cells are stored at 4°C. for increasing lengths of time, the storage is accompanied by increasing K loss and the maximum rate of accumulation observed when the cells are warmed to 37°C. at first becomes greater. If the storage at 4°C. is continued for more than 3 to 4 days, the rate of the accumulation which occurs at 37°C decreases again, the accumulation mechanism showing progressive deterioration with time even at low temperatures. This deterioration has a counterpart in the progressive deterioration (deduced from the analysis of the curves relating K content and time) of the accumulation mechanism with time at 37°C.

5. The accumulation of K occurs at a maximum rate when the concentration of glucose in the system is between 50 and 200 mg./100 ml. Its temperature coefficient over the range 27–37°C. is 2.4. In the presence of glucose and at pH 7.6, accumulation of K takes place from isotonic mixtures of KCl and LiCl or of KCl and CsCl only a little less actively than from mixtures of KCl and NaCl; i.e., the accumulation of K under optimum conditions seems to be an active process which is at least partly independent of the excretion of Na.
THE SIGNIFICANCE OF REGRESSION LINE SLOPE CHANGES IN THE QUANTITATIVE TITRATION OF COMPLEMENT COMPONENTS
Authors: Waksman Byron H.
Published: May 2004

The hypothesis is discussed that dissociable complexes are formed between elements of a test complement (C') and the reagent used to titrate it for a particular component.

Calculations are presented which demonstrate that such complex formation may give considerable changes in slopes of percentage hemolysis-log dose regression lines obtained with mixtures of C' and reagent.

It is shown that marked change of slope may occur with relatively little change in the value of the 50 per cent intercept.
BIOLOGIC SIGNIFICANCE OF THE STRUCTURE OF HYDROCARBONS
Authors: Ettisch G.
Published: May 2004

1. The biologic experiments with the links of the methane series—n-pentane, n-hexane, n-heptane, n-octane, i-octane, and pentene—gave these qualitative results: (a) The higher the number of CH2 groups, the longer the chain, the longer the average lifetime of the animal. (b) The ramified chain does not appear to act differently from the saturated straight chain with the same number of C atoms. (c) One double bond within the chain shortens the lifetime to a considerable degree.

2. The quantitative discussion shows that the lifetimes depend exponentially on the molecular weight.

3. Qualitatively the hypothesis is supported that with rising molecular weight the concentration of CH2 groups within the animal diminishes according to the vapor pressure or the thermodynamic potential. However, lifetime and these physical properties obey different functions.

4. These physical properties are of high biologic importance. But they are not sufficient to explain the biologic effects quantitatively.
POLYPLOIDY AND CANCER
Authors: Cunningham Lew , Griffin A. Clark , Luck J. Murray
Published: May 2004

The average desoxypentosenucleic acid content of individual nuclei was determined for various normal and tumor tissues, and for livers showing precancerous changes, in the rat. With certain exceptions attributable to polyploidy, the values were practically indistinguishable from each other and from values reported for cell nuclei of other mammals. The amount of this nucleic acid in diploid cells of the rat appears to be a constant, nearly equal to 6 x 10–6 micrograms. Findings of increased concentrations of this nucleic acid in tissues showing preneoplastic or neoplastic changes therefore confirm histological observations of increased cellularity and polyploidy in such tissues.
TISSUE CULTURE STUDIES
Authors: Hull Wayne , Perrone J. C. , Kirk Paul L.
Published: May 2004

The use of acetyl-3-pyridine and pyridine-3-sulfonic acid as analogues for nicotinic acid has been tested with tissue cultures of embryonic chick heart. Both roller tube and Carrel flask cultures were employed. Cell migration, appearance of the cells, and the uptake of tracer P32 were used as criteria for the action of the analogues.

Migration of the cells could be inhibited by both compounds, but at different levels. Both produced abnormal types of cells, but not the same type of abnormality. Uptake of P32 was inhibited by both compounds. Addition of nicotinic acid failed to reverse the effects of the analogues at the concentrations used.
STUDIES ON A SARCOSINE OXIDASE OF BACTERIAL ORIGIN
Authors: Kopper Paul H. ,   With the Technical Assistance of Leon Robin
Published: May 2004

A "sarcosine oxidase" was prepared from a creatinine-decomposing strain of Pseudomonas aeruginosa.

The enzyme is inactivated by drying, lyophilization, and dialysis against distilled water. No dialyzable cofactor was found.

Optimal activity of the enzyme is reached at pH 7.8. Enzyme activity is directly proportional to enzyme concentration and also to substrate concentration up to the point of saturation of enzyme with substrate molecules. One molecule of enzyme combines with one molecule of substrate.

Data concerning the effect of temperature and of a variety of chemical compounds on the enzyme are presented.

Its inactivation by heat follows the course of a first order reaction, and the critical thermal increment between 48° and 52°C. was calculated to be 103,000 calories per mol. The relationship of enzyme concentration to heat inactivation rates is illustrated.
ENZYME KINETICS AND THE RATE OF BIOLOGICAL PROCESSES
Authors: Kavanau J. Lee
Published: May 2004

It is found empirically that a simple modification of the usual theoretical kinetic formulation (in which a transformation in the temperature scale is made) describes the temperature dependence of a wide variety of biochemical processes with a greater accuracy than hitherto achieved. Used in conjunction with the formulation of the theory of absolute reaction rates this empirical relation facilitates the determination of the thermodynamic functions. The results of applying these relations to biochemical processes support the contention that in the lower temperature range of enzyme activity a thermodynamic equilibrium exists between catalytically active and inactive forms of the enzyme.

It is suggested that at low temperatures the formation of intramolecular hydrogen bridges converts reactive enzyme particles to a catalytically inactive condition, in which the active centers either lose their specific configuration or are no longer exposed to the substrate. Upon the basis of this interpretation, values of the entropy changes that are calculated theoretically are found to be in agreement with those calculated from the experimental data.

The reactive configuration of the enzyme is apparently possessed in only a relatively narrow temperature band, being lost at both high and low temperatures.

The kinetics of biological processes appear to differ only quantitatively from those of in vitro enzyme-catalyzed reactions. In both cases the non-linearity of the Arrhenius plots appears to be due to the fact that in the lower temperature range of enzyme activity a series of reactions are involved in the formation of the activated complex. These include reactions which lead to the formation of the catalytically reactive form of the enzyme followed by that which leads to the formation of the activated complex. The conversion of enzymes to the catalytically inactive form is essentially completed at temperatures of –10–0°C. in living systems, whereas in in vitro experiments with purified enzyme preparations this condition is not attained until temperatures 30–60°C. lower have been reached.
REGULATORY MECHANISMS OF CELLULAR RESPIRATION
Authors: Barron E. S. Guzman , Ardao Maria Isabel , Hearon Marion
Published: May 2004

The rate of the aerobic metabolism of pyruvic acid by bakers' yeast cells is determined mainly by the amount of undissociated acid present. As a consequence, the greatest rate of oxidation was observed at pH 2.8. Oxidation, at a slow rate, started at pH 1.08; at pH 9.4 there was no oxidation at all. The anaerobic metabolism, only a fraction of the aerobic, was observed only in acid solutions. There was none at pH values higher than 3.

Pyruvic acid in the presence of oxygen was oxidized directly to acetic acid; in the absence of oxygen it was metabolized mainly by dismutation to lactic and acetic acids, and CO2. Acetic acid formation was demonstrated on oxidation of pyruvic acid at pH 1.91, and on addition of fluoroacetic acid. Succinic acid formation was shown by addition of malonic acid. These metabolic pathways in a cell so rich in carboxylase may be explained by the arrangement of enzymes within the cell, so that carboxylase is at the center, while pyruvic acid oxidase is located at the periphery.

Succinic and citric acids were oxidized only in acid solutions up to pH 4. Malic and α-ketoglutaric acids were not oxidized, undoubtedly because of lack of penetration.
DISTANT EFFECTS OF TOXIC AGENTS
Authors: Osterhout W. J. V.
Published: May 2004

Toxic solutions applied at one end of a Nitella cell 6 cm. long may produce little or no visible change in the structure of the protoplasm at the place of application but if the opposite end is covered with water its protoplasm soon disintegrates. If the middle of the cell is covered with mineral oil this region remains normal in appearance for half an hour or more.

The result is due to the movement of substances in the cell. The loss of substances at the end where the toxic agent is applied results in loss at the opposite end if it is covered with water since water enters and travels along inside the cell carrying substances with it. This causes injury at the spot where the water enters.

The conception developed here differs fundamentally from the usual view that the effects of injury spread gradually from the region where the toxic agent is applied to the immediately adjoining regions and thence to more remote places.

The change produced by loss of substances produces an interesting pattern which deserves study.
PHOSPHORYLATION DUE TO THE OXIDATION OF SUCCINIC ACID BY CELL-FREE EXTRACTS OF ESCHERICHIA COLI
Authors: Hersey David F. , Ajl Samuel J.
Published: May 2004

Esterification of inorganic phosphate accompanies the oxidation of succinic acid by cell-free extracts of E. coli. Inorganic phosphate appears to be an essential requirement for the dehydrogenation of the C4-dicarboxylic acid.
THE MORTALITY OF BACTERIOPHAGE CONTAINING ASSIMILATED RADIOACTIVE PHOSPHORUS
Authors: Hershey A. D. , Kamen M. D. , Kennedy J. W. , Gest H.
Published: May 2004

The bacteriophage T4 containing assimilated radioactive phosphorus is inactivated at a rate proportional to the specific radioactivity of the constituent phosphorus. The beta radiation from the phosphorus makes a negligible contribution to this effect. The inactivation is therefore a direct consequence of the nuclear reaction, which kills the phage with an efficiency of about 1/12. Several phages related to T4 behave similarly.

When radioactive phage is grown from a seed of non-radioactive phage, all of the phage progeny are subject to killing by radioactive decay.

The phage is killed by beta radiation from P32 with an efficiency of about 1/100 per ionization within the particle volume.

Bacteriophage T4 and its relatives contain about 500,000 atoms of phosphorus per infective particle. Virtually all this phosphorus is adsorbed to bacteria with the specificity characteristic of the infective particles, and none of it can be removed from the particles by the enzyme desoxyribonuclease. The phosphorus content per particle, together with the published data on analytical composition, indicates a particle diameter close to 110 mµ for the varieties of phage studied.
INJURY IN RELATION TO CELL ORGANIZATION
Authors: Osterhout W. J. V.
Published: May 2004

When a part of a Nitella cell, A, is covered with water and the rest of the cell, B, is in contact with a toxic solution there is an escape of solutes at B. This is followed by the escape of solutes at A which causes the death of A. Water enters at A, flows along inside the cell, and escapes at B carrying solutes with it. When this is prevented by covering A with mineral oil the escape of solutes at A is delayed and the life of A is correspondingly prolonged. It is remarkable that this occurs in spite of the fact that the hydrostatic pressure inside the cell (turgor) drops from 6.4 atmospheres to zero.

It would seem that A might not be affected by the death of B if the escape of solutes could be prevented.
CALCULATION OF THE RATE OF TURNOVER OF A COMPOUND FROM EXCRETION DATA OF A LABELED END-PRODUCT
Authors: Wu Hsien
Published: May 2004

Methods of calculation of the rate of turnover of a compound from excretion data of a labeled end-product are compared and their relative merits discussed. In this calculation, it is assumed that the rate of turnover of the compound in question is the smallest rate constant in a series of consecutive reactions or processes.
ON THE RELATION OF THE STRENGTH-FREQUENCY CURVE IN EXCITATION BY ALTERNATING CURRENT TO THE STRENGTH-DURATION AND LATENT ADDITION CURVES OF THE NERVE FIBER
Authors: Tasaki Ichiji , Sato Masayasu
Published: May 2004

1. Determinations were done of the strength-duration, the strength-frequency, and the latent addition curves with single fiber preparations.

2. Calculation of the strength-duration and strength-frequency curves from the latent addition data by the Blair-Monnier-Hill-Rashevsky theory yielded results which showed a considerable divergence from the actual data. Calculation by the method of integrating the whole latent addition curve yielded satisfactory results.

3. The effects of electrotonus and the inactive tissues around the nerve fiber upon the strength-frequency relation were investigated.

4. It was suggested that, for alternating current stimuli and two-way condenser discharge stimuli of very high frequencies, threshold was lowered by the rectifying action of the plasma membrane.
STUDY OF SOME ENZYME SYSTEMS BY MEANS OF THE DIFFERENTIAL MICRORESPIROMETER
Authors: Entner Nathan , Kirk Paul L.
Published: May 2004

Three enzymic phenomena, inactivation by oxygen, QOO2 measurements of a dehydrogenase system, and hydrolysis of acetyl phosphate by a phosphatase of Clostridium kluyveri, were studied by means of the differential microrespirometer.

Respiration of yeast cells was also measured with the same instrument.

All results obtained in the four types of study agreed closely with earlier results obtained with the Warburg apparatus. The amount of sample needed was of the order of 1/100 to 1/200 of that necessary for comparable study with the Warburg apparatus. The advantages of the instrument in enzyme isolation and purification studies are discussed.
FAILURE TO FIND INTERCELLULAR PROTOPLASMIC CONTINUITY IN GRIFFITHSIA GLOBULIFERA
Authors: Curtis Howard J. , Myers John L.
Published: May 2004

A method was devised for estimtaing the electrical resistance between the cytoplasm of adjacent cells of the red marine alga Griffithsia globulifera. A very high resistance was found, which argues strongly against the existence of protoplasmic continuity in this species.
THE REDUCTION OF FORMALDEHYDE BY BACTERIAL CELLS
Authors: Kopper Paul H. ,   With the Technical Assistance of Leon Robin
Published: May 2004

Formaldehyde is reduced to methyl alcohol by living cells of a creatinine-decomposing strain of Pseudomonas aeruginosa. The amount of HCHO taken up in 30 minutes by 3 x 1010 cells of this organism is termed its reducing capacity. It was found to be 400 to 480 µg.

The reaction takes place over wide pH and temperature ranges, is independent of the concentration of formaldehyde as long as the latter is not high enough to exert a toxic effect on the cell, but depends on the number of bacteria present.

In cultures, 3 to 7 days old, there is a decline in reducing capacity without a proportionate decrease in the number of viable cells. On the other hand in cultures, 2 to 4 weeks old, the number of viable cells determines the amount of HCHO taken up.

N/100 NaOH depresses the reducing capacity of the organism without affecting bacterial viability.

Exposure of bacterial suspensions to temperatures of 46–52°C. for 10 minutes causes a far more rapid decrease in the number of viable cells than in reducing capacity.

Incubation of cellular suspensions with nutrient substances, which are able to support adequately the growth of the organism, for 30 minutes prior to the addition of HCHO, induces increases in reducing capacity.

The uptake of HCHO by different microorganisms seems to be related to their gaseous and nutritional requirements. Strains of P. aeruginosa and P. fluorescens are predominantly aerobic, least fastidious in their nutritional requirements, most active against HCHO, and least susceptible to the action of aureomycin and chloromycetin.

The potential significance of cellular reducing capacity is discussed.