bluuebunny/crossref_metadata_2025_split huggingface dataset:
TRACER STUDIES OF NITROGEN ASSIMILATION IN YEAST
Authors: Abrams Richard , Hammarsten E. , Reichard P. , Sperber E. 
Published: May 2004

By using N15 as a tracer the assimilation of ammonia by the yeast, Torulopsis utilis, has been studied. It has been shown that:
1. There was no measurable incorporation of N in the protein or polynucleotide purine of carbon-starved yeast.
2. When ammonia is added to nitrogen-starved yeast there is a long lag period before division begins during which the yeast rapidly synthesizes protein, this process being accompanied by a turnover of polynucleotide purine. There was no significant dilution of the N15H4+ of the medium by ordinary NH4+.
3. When yeast containing N15 is allowed to divide and grow in ordinary ammonia, the total amount of N15 in the yeast remains constant. The dicarboxylic amino acids are most diluted, while arginine and nucleic acid guanine are not diluted at all.
PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES
Authors: Price Winston H. 
Published: May 2004

1. A non-dialyzable fraction from fresh bakers' yeast stimulates the formation of S. muscae virus in cells in synthetic medium in the log phase of multiplication.
2. A similar fraction was not found in calf thymus, pancreas, or liver.
3. The active substance in this fraction has been partially purified.
4. This substance is taken up by the cells. In the absence of virus the added substance is metabolized to a form no longer available for virus formation.
5. A purified yeast fraction, which stimulates adaptive enzyme formation in yeast, has been found to stimulate virus formation in the S. muscae system.
6. The similarities between the yeast fraction that stimulates adaptive enzyme formation and the yeast fraction that stimulates virus formation are discussed.
THE ACTIVATION OF UREASE
Authors: Hofstee B. H. J. 
Published: May 2004

1. It has been shown that the activity of solutions of twice recrystallized urease is reversibly increased by moderate heating and reversibly decreased by storage in the cold, even in the frozen state.
2. Crude extracts of jack bean meal containing potent urease undergo this same type of reversible activation by heating and inactivation by cooling. Dilution has the same potentiating effect on the activity as moderate heating.
As much as a fivefold increase in activity can be obtained when a sample previously inactivated by storage for 24 hours at –10°C. is heated for 5 minutes at 60°C.
3. Solutions of crystalline urease protected by serum albumin and preserved in the cold give a constant "potential" activity over a period of more than 30 days if heated 5 minutes at 60°C. before assay.
4. The data presented have been interpreted to mean that an association between urease molecules (or between urease and other proteins) might occur, resulting in inactivation of the enzyme which would be reversed on dissociation.
5. It has been postulated that the same forces are responsible for the reversible inactivation brought about by standing at temperatures above or below the freezing point.
THE REDUCTION OF RETINENE1 TO VITAMIN A1 IN VITRO
Authors: Wald George , Hubbard Ruth 
Published: May 2004

In the surviving vertebrate retina the retinene1 liberated by bleaching rhodopsin is converted quantitatively to vitamin A1. Recent chemical studies have indicated that in this process the aldehyde group of retinene1 is reduced to the primary alcohol group of vitamin A1 (Morton; Wald).
Some time ago we brought this reaction into a cell-free brei prepared from cattle retinas. The retinas were frozen, desiccated, ground, and exhaustively extracted with petroleum ether; the resulting powder, stirred in neutral buffer solution and exposed to light, converted its retinene1 completely to vitamin A1.
Some time ago also we observed that fresh rhodopsin solutions exhibit a special type of fading in darkness following exposure to light, which is absent from the same solutions after aging. We have confirmed Bliss's identification of this reaction as the conversion of retinene1 to vitamin A1.
The system which reduces retinene1 is fractionated anatomically in the retinal rods. The outer segments of the rods, broken off from the underlying retinal tissue, are unable to convert their retinene1 to vitamin A1. In the presence of a water extract of crushed retina they do perform this conversion. On the other hand the retinal tissue from which a water extract was taken has lost this capacity. Such washed retinal tissue is reactivated by returning the washings to the solid material.
The activating effect of retinal washings on isolated outer limbs or washed retina is duplicated by a boiled muscle juice. This in turn can be replaced by reduced cozymase (reduced coenzyme I; DPN-H2); or by a mixture of DPN and fructosediphosphate.
The conversion of retinene1 to vitamin A1 is therefore a reduction in which two atoms of hydrogen are transferred to retinene1 from reduced cozymase. It is assumed that this reaction is catalyzed by an apoenzyme, retinene1 reductase, present in the rod outer limb. This process is coupled with a second system in the outer segment which reduces DPN, using hexosediphosphate or one of its derivatives as hydrogen donor. This action of DPN brings a member of the vitamin B complex, nicotinic acid amide, into an auxiliary position in the rhodopsin system.
In the isolated retina or in vitro systems the reduction of retinene1 proceeds irreversibly. Yet this reduction must be balanced by an oxidative process elsewhere in the rhodopsin cycle, since through rhodopsin as intermediate vitamin A1 regenerates retinene1.
TRANSPORT OF WATER FROM CONCENTRATED TO DILUTE SOLUTIONS IN CELLS OF NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

The transport of water from concentrated to dilute solutions which occurs in the kidney and in a variety of living cells presents a problem of fundamental importance.
If the cell acts as an osmometer we may expect to bring about such transport by creating an inwardly directed osmotic drive which is higher in one part of the cell than in other regions of the same cell. The osmotic drive is defined as the difference between internal and external osmotic pressure.
Experiments with Nitella show that this expectation is justified. If water is placed at one end of the cell (A) and 0.4 M sucrose with an osmotic pressure of 11.2 atmospheres at the other end (B) water enters at A, passes along inside the cell, and escapes at B leaving behind at B the solutes which cannot pass out through the protoplasm. Hence the internal osmotic pressure becomes much higher at B than at A. When 0.4 M sucrose at B is replaced by 0.3 M sucrose with an osmotic pressure of 8.1 atmospheres we find that water enters at B, passes along inside the cell, and escapes at A so that water is transported from a concentrated to a dilute solution although the difference in osmotic pressure of the 2 solutions is more than 8 atmospheres. The solution at B thus becomes more concentrated.
It is evident that if metabolism produces a higher osmotic pressure and consequently a higher inwardly directed osmotic drive in one region of the cell as compared with other parts of the same cell water may be transferred from a concentrated to a dilute solution so that the former solution becomes still more concentrated.
PEPTIDASE ACTIVITIES OF EXTRACTS OF SALIVARY GLANDS OF DROSOPHILA MELANOGASTER
Authors: Patterson Elizabeth K. , Dackerman Marjorie E. , Schultz Jack 
Published: May 2004

1. Peptide-splitting enzymes have been studied in buffered glycerine extracts of larval salivary glands of three stocks of Drosophila melanogaster.
2. The ultraviolet absorption spectrum of the glycerine extracts indicates the presence of a considerable amount of nucleic acid.
3. Alanylglycine (AG), leucylglycine (LG), leucylglycylglycine (LGG), glycylglycine (GG), and diglycylglycine (GGG) are split by the gland extracts in descending order of activity.
4. Of the various metals added, manganese was the only one found to give clear cut activation and that only with LGG as substrate. Cysteine inhibited the splitting of both AG and LG.
5. Comparison of the data with those published indicates the presence in the extracts in descending order of activity (at pH 7.6, 40°C.) of at least four enzymes: an AG-dipeptidase, an LG-dipeptidase, a leucineaminopeptidase, and possibly an aminopolypeptidase.
6. Optimum conditions for the measurement of the enzyme splitting AG were determined. The pH activity and kinetic data are typical for an AG-dipeptidase.
7. An enzyme (probably cathepsin II) splitting benzoyl-l-arginineamide (pH 5.0) with cysteine activation was observed to occur with very low activity in gland extracts.
RESPIRATION OF THE TISSUES OF SOME INVERTEBRATES AND ITS INHIBITION BY CYANIDE
Authors: Robbie W. A. 
Published: May 2004

A study of the metabolism of Bermuda marine invertebrates at 25°C. shows that the respiratory rates of many of the tissues approximate those of vertebrate tissues at the same temperature. There is no apparent correlation between respiratory rate and phylogenetic development: tissues from some of the simpler forms use as much oxygen per unit weight as those from certain of the more highly developed animals.
Cyanide inhibition experiments reveal a great variation in the amount of oxygen consumption which is dependent upon sensitive heavy metal systems. Three types of tissues, the jellyfish Cassiopea frondosa, the branchial tree of the sea cucumber, Stichopus möbii, and two kinds of tunicates, were completely unaffected by even 10–2M HCN. Other tissues such as sea urchin sperm, squid gills, and lobster nerve and muscle were almost completely inhibited by much lower concentrations. Most of the materials retained 20 to 40 per cent of the normal respiratory rate in 10–2M HCN. The possibility that vanadium may play a part in the oxidation-reduction systems of the completely resistant animals is discussed.
There is a thousandfold variation in the concentration of cyanide required to produce 50 per cent inhibition of respiration in the different tissues. Sea urchin sperm is 50 per cent inhibited by 10–6M HCN: the sea fan requires 10–3M for the same effect. Other tissues lie at intermediate points.
When the logarithm of the ratio of the inhibited to the uninhibited respiration is plotted against the concentration of cyanide the resulting line has a slope which in most cases approximates 1. This indicates that one mole of enzyme ordinarily combines with one mole of inhibitor.
Eggs of the sea urchin, Tripneustes esculentus, show a three- to fivefold increase in the rate of oxygen uptake on fertilization. The respiration of both the fertilized and unfertilized eggs is almost entirely inhibited by 10–4M HCN. Cell division in the fertilized eggs is blocked by somewhat less than 10–5M cyanide, a concentration which reduces respiration to 40 per cent of the normal level.
CRYSTALLINE PNEUMOCOCCUS ANTIBODY
Authors: Northrop John H. , Goebel Walther F. 
Published: May 2004

1. The immune precipitate formed by antipneumococcus horse serum and the specific polysaccharide is not hydrolyzed by trypsin as is the diphtheria toxin-antitoxin complex, and purified pneumococcus antibody cannot be isolated by the method used for the isolation and crystallization of diphtheria antitoxin.
2. Type I pneumococcus antibody, completely precipitable by Type I polysaccharide, may be obtained from immune horse serum globulin by precipitation of the inert proteins with acid potassium phthalate.
3. The antibody obtained in this way may be fractionated by precipitation with ammonium sulfate into three main parts. One is insoluble in neutral salts but soluble from pH 4.5 to 3.0 and from pH 9.5 to 10.5. This is the largest fraction. A second fraction is soluble in 0.05 to 0.2 saturated ammonium sulfate and the third fraction is soluble in 0.2 saturated ammonium sulfate and precipitated by 0.35 saturated ammonium sulfate. The second fraction can be further separated by precipitation with 0.17 saturated ammonium sulfate to yield a small amount of protein which is soluble in 0.17 saturated ammonium sulfate but insoluble in 0.25 saturated ammonium sulfate. This fraction crystallizes in poorly formed, rounded rosettes.
4. The crystallization does not improve the purity of the antibody and is accompanied by the formation of an insoluble protein as in the case of diphtheria antitoxin.
5. None of the fractions obtained is even approximately homogeneous as determined by solubility measurements.
6. Purified antibody has also been obtained by dissociating the antigen-antibody complex.
7. The protective value of the fractions is quite different; that of the dissociated antibody being the highest and that of the insoluble fraction, the lowest.
8. All the fractions are immunologically specific since they do not precipitate with Type II polysaccharide nor protect against Type II pneumococci.
9. All the fractions give a positive precipitin reaction with antihorse rabbit serum. The dissociated antibody gives the least reaction.
10. Comparison of the various fractions, either by their solubility in salt solution or through immunological reactions, indicates that there are a large number of proteins present in immune horse serum, all of which precipitate with the specific polysaccharide but which have very different protective values, different reactions with antihorse rabbit serum, and different solubility in salt solutions.
PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES
Authors: Price Winston H. 
Published: May 2004

1. The total nucleic acid synthesized by normal and by infected S. muscae suspensions is approximately the same. This is true for either lag phase cells or log phase cells.
2. The amount of nucleic acid synthesized per cell in normal cultures increases during the lag period and remains fairly constant during log growth.
3. The amount of nucleic acid synthesized per cell by infected cells increases during the whole course of the infection.
4. Infected cells synthesize less RNA and more DNA than normal cells. The ratio of RNA/DNA is larger in lag phase cells than in log phase cells.
5. Normal cells release neither ribonucleic acid nor desoxyribonucleic acid into the medium.
6. Infected cells release both ribonucleic acid and desoxyribonucleic acid into the medium. The time and extent of release depend upon the physiological state of the cells.
7. Infected lag phase cells may or may not show an increased RNA content. They release RNA, but not DNA, into the medium well before observable cellular lysis and before any virus is liberated. At virus liberation, the cell RNA content falls to a value below that initially present, while DNA, which increased during infection falls to approximately the original value.
8. Infected log cells show a continuous loss of cell RNA and a loss of DNA a short time after infection. At the time of virus liberation the cell RNA value is well below that initially present and the cells begin to lyse.
PROTEOLYTIC ENZYMES
Authors: Grob David 
Published: May 2004

1. Serum proteinase precursor was found in plasma protein fractions I and III of Cohn. Inhibitors of serum proteinase, leucoproteinase, trypsin, and papain were found in fractions IV-1 and IV-4, and to a lesser extent in fractions V and I.
2. Pancreatic, soy bean, lima bean, and egg white inhibitors inhibited trypsin stoichiometrically. Pancreatic inhibitor had comparable inhibitory activity against serum proteinase; soy bean inhibitor had somewhat less, lima bean inhibitor even less, and egg white inhibitor very little. None of these inhibitors appreciably inhibited leucoproteinase or papain.
3. Serum and fractions IV - 1 and IV - 4 had marked inhibitory activity against trypsin and leucoproteinase, and somewhat less against serum proteinase and papain. The inhibitory activity of the plasma proteins against trypsin and leucoproteinase was due almost entirely to fractions IV - 1 and IV - 4; against serum proteinase and papain fraction V was slightly more important. The "reconstituted plasma proteins" accounted for 8 to 25 per cent of the proteinase-inhibitory activity of whole serum or plasma.
4. The proteinase-inhibitory activity of serum, plasma protein fractions, and soy bean inhibitor was heat labile, while that of pancreatic, lima bean, and egg white inhibitors was relatively heat stable.
5. Reducing and oxidizing agents, in very high concentration, inhibited serum proteinase, as well as trypsin and leucoproteinase. These proteinases were not influenced by mercurial sulfhydryl inhibitors, indicating that free sulfhydryl groups do not play an important part in their activity.
THE DYNAMIC NATURE OF THERMOPHILY
Authors: Allen Mary Belle 
Published: May 2004

1. Evidence for a close relation between thermophilic and mesophilic bacteria is discussed.
2. It is shown that in the absence of nutrients thermophilic bacteria at 55°C. die as rapidly as mesophilic bacteria, and that enzyme systems of the thermophils are rapidly inactivated at this temperature.
3. It is concluded that the thermophils can live at high temperatures because they can synthesize enzymes and other cellular constituents faster than these are destroyed by heat.
4. In order to account for this great synthetic capacity at high temperatures, and for the high minimum temperatures observed for many thermophils, it is postulated that these organisms have a higher temperature coefficient of enzyme synthesis than mesophils.
METHYL GREEN-PYRONIN
Authors: Kurnick N. B. , Mirsky A. E. 
Published: May 2004

Study of the stoichiometry of the DNA-methyl green reaction by dialysis, precipitation of stain-nucleic acid mixtures, and the staining of nuclei of known DNA content, indicate that the compound consists of one dye molecule per 10 P. The significance of this result was discussed in the preceding paper (1). Histone and lanthanum (and probably other multivalent cations (3)) compete with the dye for the nucleic acid molecule, indicating a common site of attachment, presumably the phosphoric acid groups.
With care in the avoidance of procedures which might depolymerize DNA, and the use of a buffer at about pH 4.1, a quantitative histochemical method for DNA by the use of methyl green is possible. Pyronin staining appears to be of qualitative significance only. Slight differences in degree of polymerization, as between the shad and mammalian DNA appear to have no effect on methyl green staining. It may be that a critical level of polymerization for DNA staining exists. This level must exceed 20 nucleotides to account for the 10 P to 1 dye molecule and the effect on the methyl green absorption spectrum; but it may be considerably greater. Beyond this critical level, whatever it may be, further polymerization probably has no influence on staining.
TISSUE CULTURE STUDIES
Authors: Signorotti Betty , Hull Wayne , Kirk Paul L. 
Published: May 2004

Reproducible conditions have been described for quantitative tissue culturing in which all constituents including the tissue itself are added in known quantities to the culture.
The conditions for transfer, cutting, and manipulation of tissue are also described. The data show that such culturing can be performed without loss or significant alteration of the nitrogen and phosphorus content of the tissue.
TISSUE CULTURE STUDIES
Authors: Hull Wayne , Kirk Paul L. 
Published: May 2004

The content of ribo- and desoxyribonucleic acids in chick heart cultures at regular intervals after implanting has been determined both with standard culture medium and with Tyrode's solution alone.
With an inadequate medium, both nucleic acids dropped in a consistent manner but ribonucleic acid was affected to a much greater extent.
When the medium was adequate for growth, both fractions rose smoothly and paralleled each other closely, after an initial drop. The final content of each fraction was markedly higher than the amount present in the original implant.
The fundamental definition of growth and the relationship of these data to it are discussed.
INTERNAL CONVERSION IN THE PHOTOSYNTHETIC MECHANISM OF BLUE-GREEN ALGAE
Authors: Arnold William , Oppenheimer J. R. 
Published: May 2004

1. In Chroococcus a quantum of light absorbed by phycocyanin has 90 per cent the chance of doing photosynthesis that a quantum absorbed by chlorophyll has.
2. By a process analogous to internal conversion in radioactivity (but with the linear dimensions and the wave length 104 times larger) there will be transferred from phycocyanin to chlorophyll
See PDF for Equation
(a number of the order of 100) quanta for every one emitted as fluorescent light by the phycocyanin in the Chroococcus cell.
3. The yield of fluorescent light in Chroococcus is between 1 and 2 per cent.
4. The transfer of energy by internal conversion can account for the photosynthesis by phycocyanin observed by Emerson and Lewis.
TWO-PHASE FORMATION IN SOLUTIONS OF TOBACCO MOSAIC VIRUS AND THE PROBLEM OF LONG-RANGE FORCES
Authors: Oster Gerald 
Published: May 2004

In a nearly salt-free medium, a dilute tobacco mosaic virus solution of rod-shaped virus particles of uniform length forms two phases; the bottom optically anisotropic phase has a greater virus concentration than has the top optically isotropic phase. For a sample containing particles of various lengths, the bottom phase contains longer particles than does the top and the concentrations top and bottom are nearly equal. The longer the particles the less the minimum concentration necessary for two-phase formation. Increasing the salt concentration increases the minimum concentration.
The formation of two phases is explained in terms of geometrical considerations without recourse to the concept of long-range attractive forces. The minimum concentration for two-phase formation is that concentration at which correlation in orientation between the rod-shaped particles begins to take place. This concentration is determined by the thermodynamically effective size and shape of the particles as obtained from the concentration dependence of the osmotic pressure of the solutions measured by light scattering. The effective volume of the particles is introduced into the theory of Onsager for correlation of orientation of uniform size rods and good agreement with experiment is obtained. The theory is extended to a mixture of non-uniform size rods and to the case in which the salt concentration is varied, and agreement with experiment is obtained.
The thermodynamically effective volume of the particles and its dependence on salt concentration are explained in terms of the shape of the particles and the electrostatic repulsion between them. Current theories of the hydration of proteins and of long-range forces are critically discussed.
The bottom layer of freshly purified tobacco mosaic virus samples shows Bragg diffraction of visible light. The diffraction data indicate that the virus particles in solution form three-dimensional crystals approximately the size of crystalline inclusion bodies found in the cells of plants suffering from the disease.