bluuebunny/crossref_metadata_2025 huggingface dataset:
THE INTRACELLULAR GROWTH OF BACTERIOPHAGES
Authors: Anderson Thomas F. , Doermann A. H.
Published: May 2004

The growth of the virus T3 has been followed by breaking up the complexes it forms with host cells at various stages in their development and then assaying the debris for active virus particles. Two independent methods for breaking up cells were used: sonic vibration and lysis by the T6-cyanide method previously used for the study of the growth of T4.

During the first half of the latent period both treatments, as well as cyanide alone, destroyed the capacity of the complexes for producing daughter virus particles. Furthermore, the infecting particles could not be recovered from them during the first half of the latent period.

After the complexes had had 12 minutes of incubation at 30°C. both methods freed daughter virus particles from them in numbers which increased steadily with time until, near the end of the rise period, the normal burst size was reached. In general the agreement between the two yields is so good that one may conclude that both methods liberate quantitatively the mature daughter T3 particles which exist in the complexes before normal lysis occurs.
PERMEABILITY PROPERTIES OF ERYTHROCYTE GHOSTS
Authors: Teorell Torsten
Published: May 2004

1. Erythrocyte ghosts from human blood were produced by gentle water hemolysis. The ghost-containing hemolysate (about 20 mN) was added to media of different composition (KCl, NaCl, glucose, sucrose, etc.) and varying concentration ranging from 8 to 840 mN. The volume changes of the ghost cells were followed by a light absorption method. The potassium and sodium concentrations were also analyzed in some representative cases.

2. The ghosts shrank, or swelled, in two stages. An initial phase with a momentary expulsion, or uptake, of water leading to an osmotic equilibrium, was followed by a second phase in which a slow swelling or shrinking proceeded toward a final constant volume.

3. The ghosts were semipermeable in the sense that water always passed rapidly in either direction so as to maintain isotonicity with the external medium.

The relation between ghost cell volumes (V) and the total concentration (Ce) of the suspension medium can be expressed by a modified van't Hoff-Mariotte law: (Ce + a)(V – b) = constant. Here a is a term correcting for an internal pressure and b is the non-solvent volume of the ghost cells. This means that the ghosts behave as perfect osmometers.

4. On the other hand appreciable concentration differences of the K and Na ions could be maintained across the intact ghost cell membranes for long periods. Whether this phenomenon is due simply to very low cation permeability or to active transport processes cannot be decided, although the first assumption appears more probable.

5. When the ghosts were treated with small concentrations of a lytic substance like Na oleate, the alkali ion transfer was greatly increased. This seems to be a simple exchange diffusion process with simultaneous, continued maintenance of osmotic equilibrium (= the second phase).

A simplified theory is also given for the kinetics of the volume variations and ion exchange during the second phase (cf. the Appendix).

6. Miscellaneous observations on the effects of pH, and of some other substances are discussed. Some shape transformations of the ghost cells are also described.
THE EFFECT OF ELECTROLYTES ON THE CONTRACTILE ELEMENTS OF MUSCLE
Authors: Bozler Emil
Published: May 2004

The effects of changes in electrolyte concentration on muscles which had been preserved in 50 per cent glycerol or washed in water were studied. The psoas preparation of Szent-Györgyi was generally used, but smooth and cardiac muscle gave the same results.

If the preparations are immersed in 0.16 molar NaCl or KCl and if the electrolyte subsequently is washed out with distilled water, tension rises. This effect is not obtained if solutions of CaCl2 or MgCl2 are used, but it is restored by brief immersion in NaCl or KCl solutions. Changes in pH have no effect. It is concluded that divalent cations are bound more firmly than monovalent ions, but that divalent exchange with monovalent ions.

After the application of ATP washing out electrolytes produces a much larger and more rapid rise in tension. This effect persists after ATP has been washed out and seems to be due to the removal of a substance which diminishes the dissociation of bound cations.

Washing out electrolytes also causes a large increase in transparency and swelling. These effects are also enhanced by previous application of ATP and are abolished or diminished by divalent cations.

The rise in tension and the swelling are explained as the result of an increase in the charge of the polar groups of the proteins. Because this mechanism produces only a small degree of shortening, it does not explain normal contraction, but it may be a part of this process. The significance of the phenomena described in relation to recent theories of the mechanism of muscular contraction is discussed. The observations show that increase in the charge of the contractile proteins causes contraction, not relaxation, as has been commonly assumed.
ENZYMATIC DEPHOSPHORYLATION OF OVALBUMIN AND PLAKALBUMIN
Authors: Perlmann Gertrude E.
Published: May 2004

It has been shown by the work presented in this paper that it is possible to carry out a stepwise dephosphorylation of ovalbumin. With the aid of a prostate phosphatase that attacks only one of the two phosphorus-containing groups in the major component, A1, of ovalbumin, a protein, A2, containing 1 atom of phosphorus per mole has been prepared. Further dephosphorylation with an enzyme of intestinal origin gives a phosphorus-free ovalbumin, A3. Plakalbumin has been similarly dephosphorylated to give P2 and P3. Significant changes in the electrophoretic mobility accompany each dephosphorylation step. This, together with the phosphorus content of the proteins and the crystal form, has been used to characterize and study the five modifications of ovalbumin thus produced.
THE EFFECTS OF DIPHTHERIA TOXIN ON THE CECROPIA SILKWORM
Authors: Pappenheimer A. M. , Williams Carroll M.
Published: May 2004

1. The metamorphosis of the Cecropia silkworm is accompanied by large and systematic changes in the insect's sensitivity to diphtheria toxin.

2. Injection of less than 1 gamma of toxin into mature caterpillars, prepupae, or developing adults causes cessation of development followed by delayed death 1 to 5 weeks later.

3. Dormant pupae, on the contrary, are resistant to 70 gamma of toxin and may survive even this enormous dose for over 4 weeks. One-hundredth of this dose, however, prevents pupae from initiating adult development.

4. Tetanus toxin, to which the insect is insensitive, failed to duplicate any of these effects.

5. Maximal sensitivity to diphtheria toxin is characteristic of those stages in the life history which depend on the presence and function of the cytochrome system. Resistance to the toxin, as in the case of the diapausing pupa, is correlated with the existence and utilization of metabolic pathways other than the usual cytochrome system.

6. This correlation persists within the individual insect. Thus, within the diapausing pupa, the toxin fails to affect the heart in which a normal cytochrome system is absent, but, within the same insect, causes a degeneration of the intersegmental muscles in which an intact cytochrome system is present.

7. These several lines of evidence are interpreted in support of the conclusion that diphtheria toxin acts by blocking the synthesis of one or more components in the cytochrome system.
PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES
Authors: Price Winston H.
Published: May 2004

1. The synthesis of ribonucleic acid, desoxyribomicleic acid, and protein in S. muscae has been studied: (a) during the lag phase, (b) during the early log phase, and (c) while the cells are forming an adaptive enzyme for lactose utilization.

2. During the lag phase there may be a 60 per cent increase in ribonucleic acid and protein and a 50 per cent increase in dry weight without a change in cell count, as determined microscopically, or an increase in turbidity.

3. During this period, the increase in protein closely parallels the increase in ribonucleic acid, in contrast to desoxyribonucleic acid, which begins to be synthesized about 45 minutes after the protein and ribonucleic acid have begun to increase.

4. The RNA N/protein N ratio is proportional to the growth rate of all S. muscae strains studied.

5. While the RNA content per cell during the early log phase depends upon the growth rate, the DNA content per cell is fairly constant irrespective of the growth rate of the cell.

6. Resting cells of S. muscae have approximately the same RNA content per cell irrespective of their prospective growth rate.

7. While the cells are adapting to lactose, during which time there is little or no cellular division, there is never an increase of protein without a simultaneous increase in ribonucleic acid, the RNA N/protein N ratio during these intervals being approximately 0.15.

8. Lactose-adapting cells show a loss of ribonucleic acid. The purines-pyrimidines of the ribonucleic acid can be recovered in the cold 5 per cent trichloroacetic acid fraction, but the ribose component is completely lost from the system.

9. The significance of these results is discussed in relation to the importance of ribonucleic acid for protein synthesis.
THE ROLE OF SULFHYDRYL GROUPS IN THE BLEACHING AND SYNTHESIS OF RHODOPSIN
Authors: Wald George , Brown Paul K.
Published: May 2004

The condensation of retinene1 with opsin to form rhodopsin is optimal at pH about 6, a pH which favors the condensation of retinene1 with sulfhydryl rather than with amino groups. The synthesis of rhodopsin, though unaffected by the less powerful sulfhydryl reagents, monoiodoacetic acid and its amide, is inhibited completely by p-chloromercuribenzoate (PCMB). This inhibition is reversed in part by the addition of glutathione. PCMB does not attack rhodopsin itself, nor does it react with retinene1. Its action in this system is confined to the —SH groups of opsin. Under some conditions the synthesis of rhodopsin is aided by the presence of such a sulfhydryl compound as glutathione, which helps to keep the —SH groups of opsin free and reduced.

By means of the amperometric silver titration of Kolthoff and Harris, it is shown that sulfhydryl groups are liberated in the bleaching of rhodopsin, two such groups for each retinene1 molecule that appears. This is true equally of rhodopsin from the retinas of cattle, frogs) and squid.

The exposure of new sulfhydryl groups adds an important element to the growing evidence that relates the bleaching of rhodopsin to protein denaturation. The place of sulfhydryl groups in the structure of rhodopsin is still uncertain. They may be concerned directly in binding the chromophore to opsin; or alternatively they may furnish hydrogen atoms for some reductive change by which the chromophore is formed from retinene1.

In the amperometric silver titration, the bleaching of rhodopsin yields directly an electrical variation. This phenomenon may have some fundamental connection with the role of rhodopsin in visual excitation, and may provide a model of the excitation process in general.
OLFACTORY STIMULATION OF BLOWFLIES BY HOMOLOGOUS ALCOHOLS
Authors: Dethier V. G. , Yost M. T.
Published: May 2004

The response of the blowfly Phormia regina to stimulation by alcohols in the vapor phase has been investigated by means of an olfactometer which permitted quantitative control of stimulus concentration. The median rejection threshold was selected as a criterion of response. As was true in the case of contact chemoreception, the distribution of thresholds in the fly population is normal with respect to the logarithm of concentration. In terms of molar concentration the alcohols are rejected at logarithmically decreasing concentration as chain length is increased. Beyond decanol there is no further stimulation. When thresholds are expressed as pressures and plotted against saturated vapor pressures on logarithmic coordinates, the data fit a line the slope of which is not significantly different from 1; i.e., the thresholds vary directly with vapor pressure. Individual threshold values, however, deviate significantly from this line. and the deviation must be ascribed to other factors which have not as yet been identified. When thresholds are expressed as activities, all alcohols are equally stimulating. It appears that the limiting process of olfaction, at least in so far as the normal alcohols are concerned, may involve an equilibrium process. Conformity to this concept is most exact for intermediate members of the series.
EFFECT OF POTASSIUM DEFICIENCY ON CARBON DIOXIDE, CATION, AND PHOSPHATE CONTENT OF MUSCLE
Authors: Gardner Lytt I. , MacLachlan Elsie A. , Berman Helen
Published: May 2004

Albino rats weighing 160 to 175 gm. were fed a complete synthetic diet containing 0.003 per cent potassium and 0.7 per cent sodium for 40 days. Controls were given the same diet plus adequate added potassium.

1. Data from analyses of serum and skeletal muscle showed (a) a fall in serum chloride concentration and an increase in serum carbon dioxide concentration and pH in the potassium-deficient rats; (b) increases of sodium, magnesium, and calcium and a decrease of potassium in the muscle of the potassium-deficient rats; (c) no change of muscle chloride or carbon dioxide concentrations in the potassium-deficient rats.

(2) Application of the Wallace-Hastings calculations to these data revealed (a) intracellular pH of the skeletal muscle of the normal rat to be 6.98 ± 0.08; (b) an increase in serum partial pressure of carbon dioxide (pCO2) in potassium deficiency, together with increases in concentrations of [H2CO2] and [HCO3-] per kg. extracellular water and [H2CO3] per kg. cell water; (c) a decrease in values for [CO2] and [HCO3-] per kg. intracellular water; (d) a fall of intracellular pH in potassium deficiency to 6.42 ± 0.05.

(3) Analyses of sacrospinalis muscle from five men undergoing operation for ruptured intervertebral disc showed a mean value of 9.46 ± 1.31 mM carbon dioxide per kg. blood-free tissue.

Some problems of interpretation of data are briefly discussed.
UPTAKE OF GLYCINE-N15 BY COMPONENTS OF CELL NUCLEI
Authors: Daly Marie M. , Allfrey V. G. , Mirsky A. E.
Published: May 2004

1. The uptake of glycine-N15 by components of cell nuclei was studied. The nuclear components were derived both from tissues with high metabolic rates-mammalian liver, kidney, and pancreas-and from cells with relatively low rates of metabolism-avian erythrocytes and echinoderm sperm. N15 uptake by nuclear components of liver, kidney, and pancreas was far more rapid than by those of erythrocytes and sperm.

2. The nuclear components of liver, kidney, and pancreas for which measurements were made were DNA, histone, and residual protein of chromatin. Uptake into DNA was low, into histone higher, and into residual protein much higher still, being comparable with that into mixed cytoplasmic protein.

3. A comparison of the uptake of N15 by the chromosomal components, histone and DNA of liver, pancreas, and kidney showed that chromosomal "activity" varies in different cells and also in the same cell depending upon its over-all activity.
THE NUCLEIC ACIDS OF SOME INSECT VIRUSES
Authors: Wyatt G. R.
Published: May 2004

Purine and pyrimidine bases have been estimated from the desoxyribonucleic acids of eleven insect viruses. Their proportions vary in the different species in a balanced way so that the molar ratios adenine:thymine and guanine:cytosine are constant and close to unity, whereas adenine + thymine:guanine + cytosine ranges from 0.71 to 1.87. This ratio is identical for some biologically dissimilar viruses, and no general parallelism is evident between DNA composition and biological relationship. Two different viruses from one host have distinct DNA's.
FORMATION OF PROTEIN IN THE PANCREAS
Authors: Daly Marie M. , Mirsky A. E.
Published: May 2004

1. The total known secretory enzyme content of the mouse pancreas has been determined and found to represent about 20 per cent of the weight of the dry, fat-free tissue.

2. The changes in secretory enzyme content that occur during the cycle of secretion and synthesis have been measured.

3. In the course of the cycle no significant changes have been found in DNA or RNA content of pancreatic tissue.

4. Constancy of DNA content, along with other observations, indicates that total protein content of the gland remains substantially unchanged during the cycle of secretion and synthesis. These facts point to the conclusion that following upon the secretion of enzyme protein, synthesis of new protein takes place relatively rapidly in the exocrine cells of the pancreas and this protein is then gradually transformed into the characteristic pancreatic enzyme proteins.
OXYGEN DISSOCIATION OF WHOLE BLOOD STUDIED POLAROGRAPHICALLY
Authors: Markus Gabor , Baumberger J. Percy
Published: May 2004

The polarographic current of whole blood is in excess of that given by plasma at the same oxygen tension. The magnitude of this difference depends on (a) the oxygen content of the sample and thus is determined by the red blood cell content and by the state of oxygen saturation of hemoglobin, and (b) on the rate of dissociation of oxyhemoglobin and therefore is influenced by changes in pH, pCO2, and temperature.

The total current at 37°C. is proportional to the oxygen content of the sample and can be used to determine the latter.

The theoretical basis of the studied phenomena is discussed in detail.
AN ANALYTICAL STUDY OF IN VIVO SURVIVAL OF LIMITED POPULATIONS OF ANIMAL RED BLOOD CELLS TAGGED WITH RADIOIRON
Authors: Brown I. W. , Eadie G. S.
Published: May 2004

Animal red blood cell in vivo survival curves, obtained by the radioiron tagging of populations of approximately the same age followed by the administration of non-radioactive iron to suppress radioiron reutilization, have been subjected to mathematical analysis on the basis of the three following assumptions:—

(A) Red blood cells disappear from the circulation as the result of senescence: there is an average life span around which the life spans of individual cells are distributed in the usual way.

(B) Red blood cells may be removed from the circulation by a process of random destruction which continuously removes a constant fraction of the cells present at any moment irrespective of age or other characteristics.

(C) Under the conditions of the experiments described, a fraction of the radioiron, constant for each animal, is reutilized in new red cell formation when released by red cell destruction.

This mathematical analysis indicates the following average life spans with the respective standard errors of the mean: dog 107 days ± 1.14; rabbit 67.6 days ± 1.94; cat 68.4 ± 1.50.

The mathematical treatment presented has permitted a consideration of the theoretical variation of red cell life spans which was found in these experiments to be relatively small for all three species studied. In the rabbit and cat 2.5 per cent of tagged populations of red cells of the same age would theoretically have disappeared by senescence 17 days before the average life span was reached. The variation of red cell life in the dog was slightly less.

Animals of the three species studied, in spite of apparently normal health, exhibited varying degrees of random destruction of both autogenous and transfused fresh normal homologous red cells. As yet, we have no explanation for this random loss of cells occurring in apparently healthy normal animals.

The method of mathematical analysis presented is applicable to animal red cell survival studies employing radioiron in which differing rates of random destruction are operating in the removal of red cells.
IMMUNOLOGICAL STUDIES OF INSECT METAMORPHOSIS
Authors: Telfer William H. , Williams Carroll M.
Published: May 2004

1. The cell-free blood of the Cecropia silkworm produces a maximum of nine bands of antigen-antibody precipitate when reacted in antiserum-agar tests with antisera prepared by injecting Cecropia extracts into rabbits. The blood antigens producing these bands of precipitate have the properties of proteins in that they are non-dialyzable, labile at 75°C., and salted out by 75 per cent saturated ammonium sulfate. One antigen was identified as a carotenoid protein.

2. Six bands of precipitate were selected for further study. Absorption tests revealed that the blood, at all stages of metamorphosis, is capable of precipitating the antibodies which produce five of these bands. This result indicates that five of the six antigens are present in the blood throughout metamorphosis. The sixth antigen is undetectable in blood from fourth instar larvae, appears in the blood late in the fifth instar, persists during the pupal stage, and disappears again during adult development.

3. When blood samples from various stages of metamorphosis were tested in antiserum-agar tubes, the rates of advance of the six bands of precipitate underwent systematic change in close correlation with the morphological stage of the silkworm's metamorphosis. These changes are interpreted in terms of concentration changes of the corresponding blood antigens. The validity of this interpretation was tested in several ways, with the conclusion that the interpretation was generally acceptable for the system under consideration.

4. All six antigens appear to increase in concentration during the last larval instar and to decrease in concentration during the period of adult development. However, each antigen has its own characteristic pattern of concentration change which differs from those of the other five. In order to explain this diversity, we conclude that the physiological mechanisms which regulate the synthesis and utilization of the blood antigens control each antigen on an individual basis.
THE MOTILITY OF RAM AND BULL SPERMATOZOA IN DILUTE SUSPENSION
Authors: Blackshaw A. W.
Published: May 2004

1. Ram and bull spermatozoa suspended in a glucose-sodium chloride solution rapidly lose motility at relatively high dilutions. The substitution of chloride-free diluents does not alter the phenomenon.

2. The rapid immobilization of ram and bull spermatozoa due to high dilution may be partially prevented by the addition of supernatants of either ram or bull semen, although motility is not maintained at the same level as in a more concentrated specimen. Various other substances which also partially protect spermatozoa are egg albumin, plasma albumin, plasma gamma globulin, starch, and glycogen.

3. Washing ram spermatozoa six times greatly reduces motility. This is not restored by the addition of ram seminal plasma which, however, reverses the concurrent head agglutination.

4. Washing ram and bull spermatozoa four times results in considerable loss of motility and head agglutination both of which may be reversed by the addition of seminal plasma.

5. Potassium chloride at 0.005 M concentration partially restores the motility of four times washed ram spermatozoa at 24°C. or 37°C. but not that of similarly treated bull spermatozoa.
FLUORESCEIN-CONJUGATED BOVINE ALBUMIN
Authors: Schiller Alfred A. , Schayer Richard W. , Hess E. L.
Published: May 2004

Fluorescein-bovine albumin conjugates have been prepared and found not to differ appreciably in size, shape, and homogeneity from the precursor, bovine serum albumin. Fluorescein has also been conjugated to rat plasma proteins.

Their disappearance rates from the circulation of rats correspond with those obtained from the use of isotope labeling.

Their sites of localization in rat tissues were shown to be in the cytoplasm but not in the nuclei of Kupffer cells, fixed macrophages, granulocytes, and proximal renal tubules. Adsorption to endothelium was a characteristic finding. Extracellular localizations were predominantly in the lumina of blood vessels and proximal renal tubules (but never in the lumina of collecting tubules), and the interstitial fluid of skeletal and cardiac muscle (but not that of glandular organs such as the adrenals, liver, and spleen).

BAC absorption from the skin of rabbits requires days whereas sodium fluorescein absorption is measured in hours, attesting to the persistence of the colloidal state of BAC in vivo.

Fluorescein conjugates have been used to visualize the transcapillary passage of circulating proteins in the mesenteric circulation of frogs and rats by direct microscopic observation and found to diffuse slowly in the manner predicted for plasma proteins.

The normal cutaneous vessels of the rat are impermeable in the gross to the labeled proteins; second degree burn promptly increases the permeability of these vessels rendering the presence of the label detectable in the gross in the skin.

The process of labeling does not render guinea pig albumin antigenic, although slight antigenicity results from labeling whole plasma protein.

It is believed that sufficient biological evidence is presented to support the conclusion that fluorescein-conjugated plasma proteins, particularly albumin, behave in vivo like their native precursors.
THE SPECIFIC HEAT OF RED CELLS, WITH SPECIAL REFERENCE TO THE PARACRYSTALLINE RAT RED CELL
Authors: Ponder Eric
Published: May 2004

The specific heat of the rat red cell, kept in cold sodium citrate, changes in the neighborhood of 6°C., the temperature near which the cell passes from its paracrystalline state to a state of greater disorder. The change in the specific heat is from 0.74 with a standard deviation of ±0.022 (paracrystalline state) to 0.87 with a standard deviation of ±0.021 (normal state).

Although it has been looked for, no evidence of a change in specific heat has been found, between 1°C. and 15°C., in the case of the human red cell or of the fresh rat red cell in saline or plasma.
EFFECT OF HELIUM ON THE RESPIRATION AND GLYCOLYSIS OF MOUSE LIVER SLICES
Authors: South Frank E. , Cook Sherburne F.
Published: May 2004

It has been shown that helium has the ability to affect variously the rates of certain metabolic reactions in vitro as compared to nitrogen. An attempt has been made to approximate the sites of action in mouse liver preparations.

The following results have been obtained by the substitution of a mixture of 80 per cent helium and 20 per cent oxygen for air: (a) An increase in the rate of oxygen consumption and carbon dioxide production to the same degree, the respiratory quotient remaining unchanged. (b) A decrease in the magnitude of cyanide inhibition. The effectiveness of helium increases with the degree of the cyanide inhibition. (c) No effect on the activity of slices which have been poisoned with fluoride when either lactate or pyruvate has been added as a substrate. (d) A change in the rate, and the slope of the curve of oxygen consumption in liver homogenates which are utilizing pyruvate as a substrate.

The use of helium relative to nitrogen under anaerobic conditions causes: (a) A depression of the glycolytic rates in both mouse liver slices and diaphragm. (b) An increase in the carbon dioxide evolution and lactic acid production of mouse liver homogenates oxidizing either glucose and hexose diphosphate, or hexose diphosphate alone.

In neither slices nor homogenates does the addition of fluoride and the use of pyruvate as the hydrogen acceptor alter the fundamental response of the preparations.

The following hypotheses have been advanced and discussed in order to explain the observed phenomena:

1. Helium does not alter the substrate utilized by the tissue.

2. The gas interferes in some way with the cyanide-cytochrome oxidase bond, but may not affect cytochrome oxidase in the absence of cyanide.

3. The citric acid cycle is not subject to the influence of helium in tissue slices, but is altered in an unexplained fashion in homogenates. It is postulated that a rearrangement of particulate surfaces may be the significant factor here.

4. The glycolytic cycle is the site of both an inhibitory and an acceleratory effect of helium. The locus of the inhibition lies above the aldolase reaction and that of the acceleration between the aldolase and enolase reactions.
STIMULATION OF GERMINATION AND RESPIRATION OF THE SPORES OF BACILLUS MEGATHERIUM BY MANGANESE AND MONOVALENT ANIONS
Authors: Levinson H. S. , Sevag M. G.
Published: May 2004

1. The addition of manganese in a concentration as low as 1.8 x 10–5 M stimulates both respiration and germination markedly and eliminates the need for heat activation of spores respiring in inorganic salts-glucose.

2. Rapid germination and respiration of B. megatherium spores require a proper balance of ions in the nutrient medium. The repressive effect of a high phosphate concentration can be eliminated or balanced by chloride, or by other monovalent anions. Adenosine can relieve the necessity for chloride in such a system.
CYTOCHROME OXIDASE ACTIVITY DURING DIAPAUSE AND METAMORPHOSIS OF THE JAPANESE BEETLE (POPILLIA JAPONICA NEWMAN)
Authors: Ludwig Daniel
Published: May 2004

1. Determinations were made on the activity of cytochrome oxidase of individual Japanese beetles during growth, diapause, and metamorphosis. All readings were made on homogenates at a dilution of 1:1,000, except for adult beetles, when the final dilution was 1:10,000.

2. The activity of the enzyme increased during larval growth from a low value of 0.022 in the second instar, to high values ranging from 0.074 to 0.083 in diapause third instar larvae.

3. The high activity of cytochrome oxidase during larval diapause indicates that this condition may be physiologically different from that occurring in the egg or pupal stages of most other insects.

4. During metamorphosis, the activity of cytochrome oxidase follows the characteristic U-shaped curve associated with respiratory metabolism. It thus appears that most of the oxidation occurring in metamorphosing individuals is mediated through the cytochrome system.

5. The activity of cytochrome oxidase is significantly higher in the adult male than it is in the adult female; the values (calculated on the basis of a 1:1,000 dilution) were 0.40 ± 0.028 and 0.25 ± 0.012, respectively.
VOLUME CHANGES, ION EXCHANGES, AND FRAGILITIES OF HUMAN RED CELLS IN SOLUTIONS OF THE CHLORIDES OF THE ALKALINE EARTHS
Authors: Ponder Eric
Published: May 2004

1. Concentrations of BaCl2, MgCl2, SrCl2, and CaCl2 can be found in which the volume of washed human red cells remains almost unchanged for short periods of time; in more concentrated solutions the cells shrink, and in less concentrated ones they swell. Between tonicities of about 1.5 and 0.75, the van't Hoff-Mariotte law applies roughly, but at lower tonicities the red cell volume is anomalously great, sometimes in the absence of hemolysis.

2. If the cells are allowed to stand at 4°C. in the media of different tonicities, the volume changes are not maintained. The volumes decrease in a complex way, and the decreases are accompanied by a loss of K from the cells and an entry of the external cation into them.

3. With two exceptions, these ion exchanges are not accompanied by any important changes in the osmotic, mechanical, or heat fragility of the red cells. The exceptions are a marked effect of BaCl2 on heat fragmentation, and of CaCl2 on osmotic and mechanical fragilities.
RELATIONSHIPS BETWEEN TOBACCO MOSAIC VIRUS BIOSYNTHESIS AND THE NITROGEN METABOLISM OF THE HOST
Authors: Commoner Barry , Schieber Dorothy L. , Dietz Phyllis M.
Published: May 2004

1. Comparisons of the nitrogen content of TMV-infected and uninfected tobacco leaf discs at various times after inoculation show that virus synthesis is associated with a net increase in protein content. This excess protein is due to: (a) TMV, (b) an excess in insoluble protein which develops soon after inoculation and ends about 100 hours before cessation of TMV synthesis, and (c) an excess in soluble non-virus protein, which is variable in size and which only occurs during the time of virus synthesis. A deficiency in non-protein nitrogen occurs during the time when virus appears.

2. Isotope experiments with N15-labelled nutrient show that: (a) The bulk of TMV nitrogen is derived from the free ammonia of the host tissue. (b) Amino acid residues of TMV protein are not derived from the corresponding free amino acids in the host. (c) The appearance of TMV is preceded by the synthesis of an insoluble precursor of the virus which is then converted into TMV or some soluble intermediate protein. This effect is associated with a cell particulate which represents a small fraction of the total insoluble protein. (d) Infected tissue synthesizes de novo small amounts of soluble non-virus protein, which may represent intermediates in TMV synthesis. (e) Infected tissue fails to synthesize a rapidly turned-over soluble protein which is synthesized in comparable uninfected tissue. (f) TMV synthesis is preceded by a temporary enhancement of the metabolic stability of an insoluble protein component.

3. The results lead to the conclusion that TMV formation is due to diversion of some part of the host's protein-synthesizing apparatus from its normal course.
NUCLEIC ACID ECONOMY IN BACTERIA INFECTED WITH BACTERIOPHAGE T2
Authors: Hershey A. D.
Published: May 2004

1. During the first 10 minutes of viral growth following infection of E. coli by phage T2 in broth, a pool of DNA is built up that contains phosphorus later to be incorporated into phage. This pool receives phosphorus from, but does not contain, the bacterial DNA.

2. After 10 minutes, DNA synthesis and phage maturation keep pace in such a way that the amount of precursor DNA increases moderately for a time and then remains constant.

3. The pool so described is defined in terms of the kinetics of transport of phosphorus from its origins in the culture medium, the bacterial DNA, and the DNA of the parental phage, to the viral progeny. The most interesting parameter of this system is the size of the precursor pool, which measures 10–9 to 2 x 10–9 µg. DNA-P (50 to 100 phage particle equivalents) per bacterium.

4. Neither the precursor nor the intracellular phage population exchanges phosphorus with the phosphate in the medium. More interestingly, the phosphorus in mature phage does not exchange with phosphorus in the precursor, showing that maturation is an irreversible process.

5. Maturation is also a remarkably efficient process. About 90 per cent of labeled phosphorus introduced early into the precursor pool is later incorporated into phage.

6. Viral DNA is synthesized at the rate of about 1.5 x 10–10 µg. DNA-P (7 or 8 phage particles) per bacterium per minute. This is somewhat faster than bacterial DNA is formed, but considerably slower than RNA is formed, in uninfected bacteria.

7. The transport of phosphorus from medium to viral precursor DNA takes an average of 8 or 9 minutes, and from precursor to phage an additional 7 or 8 minutes.

8. Metabolically active RNA has been detected in infected bacteria.
LOW LEVEL IMPEDANCE CHANGES FOLLOWING THE SPIKE IN THE SQUID GIANT AXON BEFORE AND AFTER TREATMENT WITH "VERATRINE" ALKALOIDS
Authors: Shanes Abraham M. , Grundfest Harry , Freygang Walter
Published: May 2004

The increase in conductance, which accompanies the spike in the presence of sea water, is followed by a decrease to below the resting level, here designated as the "initial after-impedance," which lasts 3 msec. and is 3 per cent as great as the increase. Treatment with cevadine usually obliterates the latter but leaves the former essentially unaltered. In addition, the alkaloid gives rise to periodic conductance increases followed by a prolonged, exponentially decaying elevated conductance (the "negativity after-impedance") which correspond closely to potential oscillations and to the negative after-potential. These are also only a few per cent of the major conductance change. Veratridine causes a conductance increase which lasts longer and which also conforms closely with earlier after-potential results.

Preliminary calculations indicate that the negativity after-impedance and the negative after-potential may be due to the subsidence of an elevated chloride permeability. However, no satisfactory explanation is available for the initial after-impedance or for the temporal course of the conductance changes associated with oscillations in membrane potential.
OBSERVATIONS ON THROMBIN INACTIVATION BY HUMAN SERUM
Authors: Mihályi Elemer
Published: May 2004

The inactivation of thrombin by serum follows a first order kinetics with thrombin concentrations of the order of 20 to 40 units per ml. of serum. With higher thrombin concentrations of 300 to 600 units per ml. of serum, the rate slows down and not the logarithm of the clotting time, but the clotting time itself increases proportionally with the incubation time.

The antithrombic factor is stable at +4°C. for a period of 2 weeks, or for 3 months at –15°C. Heating over 58°C. destroys it rapidly. The heat inactivation has an energy of activation of 121,000 cal.

With low thrombin concentrations the rate of thrombin inactivation increases linearly with increasing serum concentration. The pH optimum of the inactivation is at 8.5. Increasing the temperature increases the rate. The energy of activation of the thrombin destruction by serum is 14,000 cal.

Heparin increases the rate considerably with low thrombin concentrations, but does not affect the rate with high thrombin concentrations. The effect of heparin can be abolished with protamine or toluidine blue. Some other reagents were also tested with respect to their effect upon the rate of inactivation of thrombin by serum.
THE MOLAR EXTINCTION OF RHODOPSIN
Authors: Wald George , Brown Paul K.
Published: May 2004

The molar extinction of rhodopsin is 40,600 cm.2 per mole equivalent of retinene; i.e., this is the extinction of a solution of rhodopsin which is produced by, or yields on bleaching, a molar solution of retinene. The molar extinctions of all-trans retinene and all-trans retinene oxime have also been determined in ethyl alcohol and aqueous digitonin solutions.

On the assumption that each chromophoric group of rhodopsin is made from a single molecule of retinene, it is concluded that the primary photochemical conversion of rhodopsin to lumi-rhodopsin has a quantum efficiency of 1; though the over-all bleaching of rhodopsin in solution to retinene and opsin may have a quantum efficiency as low as one-half.

On bleaching cattle rhodopsin, about two sulfhydryl groups appear for each molecule of retinene liberated. In frog rhodopsin the —SH:retinene ratio appears to be higher, 5:2 or perhaps even 3:1. Some of this sulfhydryl appears to have been engaged in binding retinene to opsin; some may have been exposed as the result of changes in opsin which accompany bleaching, comparable with protein denaturation.
A QUANTITATIVE STUDY OF METACHROMASY IN SYNOVIAL FLUID AND MUCIN
Authors: Hamerman David J. , Schubert Maxwell
Published: May 2004

Spectrophotometric measurements on synovial fluid and solutions of mucin and hyaluronate in the presence of methylene blue showed that:

1. Dialyzed synovial fluid was not metachromatic.

2. Albumin and gelatin at a concentration of 1 mg. per ml. inhibited the metachromasy of strong chromotropes.

3. Reduction of the protein of synovial fluid by the use of proteolytic enzymes still did not make the synovial fluid chromotropic.

4. Mucin solutions, with a protein content equal to that of protease-treated synovial fluid, were intensely metachromatic.

5. Sulfur-free hyaluronate produced intense metachromasy.

The evidence presented indicates that in its native state in synovial fluid hyaluronate is either bound or its anionic groups are not entirely free.
ULTRAVIOLET LIGHT AND THE MITOTIC CYCLE IN THE SEA URCHIN'S EGG
Authors: Blum Harold F. , Kauzmann Elizabeth Flagler , Chapman George B.
Published: May 2004

The effect of ultraviolet light in delaying certain events in the cell division cycle has been examined. The time to fusion of the egg and sperm nucleus is not affected by doses of ultraviolet that cause considerable delay in other parts of the cycle. The principal delay occurs before anaphase. Between anaphase and cleavage there is only slight delay. The "refractory period" during which the radiation does not delay the immediate cycle of cell division, does not seem to represent complete refractoriness of the mitotic cycle to interference during this period.
THE REACTIVATION OF HEAT-INACTIVATED HYALURONIDASE
Authors: Emmart E. W. , Longley J. B.
Published: May 2004

1. Following heat denaturation after an hour at boiling temperature bovine testicular hyaluronidase has been shown to undergo spontaneous reactivation.

2. This reactivation is a function of the temperature at which the enzyme solution is maintained.

3. Secondary inactivation was observed to follow a reactivation of the enzyme at all concentrations observed.

4. There is a relationship between hydrolysis by the enzyme and the purity of the substrate. The demonstration of activity of the freshly boiled enzyme by the turbidimetric reduction technique is dependent upon the purity of the substrate.

5. These reactions have been demonstrated using preparations of bovine and avian hyaluronic acid and porcine chondroitin sulfate.
CHANGES IN RESTING POTENTIAL DUE TO A SHIFT OF ELECTROLYTES IN THE CELL PRODUCED BY NON-ELECTROLYTES
Authors: Osterhout W. J. V.
Published: May 2004

Experiments on Nitella indicate that the resting potential is due chiefly to the outwardly directed diffusion potential of electrolytes which is set up at the inner, non-aqueous, protoplasmic surface surrounding the vacuole. We might therefore expect that any change in the concentration of these electrolytes would affect the resting potential. The experiments described here indicate that this expectation is justified.

When a sucrose solution is applied at one end of the cell and water is placed at another spot, water enters at the latter, passes along inside the cell, and escapes into the sucrose solution, but the electrolytes are unable to escape into the sucrose solution (except very slowly) so that the concentration of electrolytes increases in the region in contact with the sucrose solution. Hence the potential at this spot increases. At the other spot where the water enters, the concentration of electrolytes decreases and the potential at this spot falls off.

The changes can be carried out reversibly without injury to the cell.
ISOLATION OF PURIFIED COPPER PROTEIN FROM HORSE LIVER
Authors: Mohamed Mostafa S. , Greenberg David M.
Published: May 2004

1. A procedure is described for isolating a copper protein from horse liver in pure form, in a state that appears to be crystalline.

2. This copper protein is colored blue-green, and its copper content varied between 0.3 and 0.4 per cent. No indication of any catalytic properties was obtained in the limited number of tests made. Because of its variable copper content, the protein may function for the storage of copper in the body.

3. The copper could be removed partly from the protein by dialysis against cyanide, and a colorless crystalline protein was obtained by lowering the pH to 5.0, followed by dialysis. The original blue-green color of the protein could be restored by dialysis against copper acetate solution.
SILICON METABOLISM IN DIATOMS
Authors: Lewin Joyce C.
Published: May 2004

1. Cells of the fresh water diatom Navicula pelliculosa may be grown in a mineral medium containing a low concentration of silicon. When transferred to a fresh silicate solution and incubated under non-growing conditions such deficient cells rapidly take up silicon from the medium.

2. The utilization of silicon is an aerobic process.

3. When deficient cells are washed with distilled water or saline, their ability to utilize silicon is impaired whereas respiration is unaffected.

4. The ability of washed cells to take up silicon can be partially restored with sulfate or ascorbic acid, and is completely restored by Na2S, Na2S2O3, glutathione, l-cysteine, dl-methionine, or ascorbic acid plus sulfate.

5. The sulfhydryl reagent, CdCl2, inhibits silicon utilization of unwashed cells at concentrations which do not affect respiration. This inhibition similarly is reversed by glutathione or cysteine.

6. However, sodium iodoacetate or sodium arsenite inhibits respiration and silicon utilization at the same concentrations.

7. The silicon taken up by deficient cells is deposited at the cell surface as a thickening of the existing silica frustules.

8. Sulfhydryl groups in the cell membrane may be involved in silicon uptake by diatoms.
EXPERIMENTAL VARIATIONS IN SONIC FRAGILITY OF RED CELLS
Authors: Guillet Marilyn , Fowler Richard C.
Published: May 2004

A magnetostriction oscillator has been used for determining the relative fragility of human red cells to 9000 cycle vibrations under some different environmental conditions. The destruction of the cells is a logarithmic function of time according to the equation

See PDF for Equation.

Hypertonic saline solution, saponin, preheating, alcohol, and ether in subhemolytic concentrations decrease the fragility of human red cells subjected to sonic oscillation. Hypotonic saline, preheating to 50°C. for 3 minutes, and hemolytic concentrations of ether increase the fragility of red cells to 9 kc. vibrations. Following preheating of the cells, and in the presence of saponin the destruction deviates slightly from a true logarithmic rate of hemolysis.
THE ROLE OF HIGH IONIC CONCENTRATIONS IN PROTECTION AGAINST X-IRRADIATION
Authors: Bachofer C. S. , Pottinger M. Aelred
Published: May 2004

Various levels of protection against x-irradiation damage in bacteriophage T1 may be obtained by the addition of inorganic salts to the aqueous virus suspensions during irradiation.

The highest survival values are obtained with the nitrite salts, and their protective power is attributed primarily to their function as reducing agents.

The nitrate ion shows greater protection than the corresponding sulfate or chloride ions. This may be due in part to the lower energy level of the nitrate ion, by reason of resonance. Since greater expenditure of incident energy is required to raise the ion from the ground state, the energy thus dissipated may be ineffective in the inactivation of virus particles.

The ammonium salts exhibit protection of a different order of magnitude from that of the metallic salts. It is postulated that NH4+ protects in a threefold way: (a) dehydration, (b) reduction, in which the ammonia is oxidized to nitrite and the nitrite to nitrate, and (c) stabilization of the virus protein.

Metallic salts likewise protect, but a point of maximum protection is reached in lower concentrations than in the case of the ammonium salts. After this maximum protection is reached, there is a rapid decline in survival with increased concentration. This prevents protection of the order of magnitude that can be obtained with the ammonium salts. It is postulated that a specific cationic interaction with the phage may be responsible for the decreased protection.

Bacteriophage is protected during x-irradiation by an alkaline pH, in the case of NH4OH. This protection could not be produced with NaOH, presumably because of the greater hydrolysis of the protein components of the virus particle in solutions of NaOH, whereas NH4OH stabilizes the protein.