bluuebunny/crossref_metadata_2025 huggingface dataset:
THE BIOLOGICAL CONTROL OF GLYCOGEN METABOLISM IN AGROBACTERIUM TUMEFACIENS
Authors: Madsen N. B.
Published: October 2017

The hypothesis has been advanced that the inhibition of phosphorylase by uridine diphosphate glucose (UDPG), together with the fact that the latter compound is the substrate for glycogen synthetase, is the basis of a mechanism for the biological control of glycogen metabolism in Agrobacterium tumefaciens. Experiments were designed to test this hypothesis on the assumption that such a control mechanism would manifest itself by the concentrations of UDPG and glycogen bearing some relationship to each other during various stages of growth and nutrition. Glycogen levels in the cells increased markedly during the lag phase of growth, decreased during the exponential growth phase, and increased again as growth ceased due to the depletion of nitrogen from the medium (nitrogen starvation). The UDPG concentration paralleled these changes, and a high positive correlation between the concentrations of UDPG and glycogen was demonstrated. The addition of ammonium chloride to nitrogen-starved cells caused a prompt resumption of growth, a sharp decrease in the UDPG concentration, and a somewhat smaller decrease in glycogen concentration. Cells placed in buffered salt solution and aerated had a low concentration of UDPG and exhibited a steady decline of the glycogen reserves. Although factors other than those considered here may also be of importance in the control of glycogen metabolism in this organism, the data in general support the hypothesis advanced above.
SYNTHESIS OF SHIKIMIC ACID-C14IN PINUS RESINOSA, AIT. FROM SOME C14-LABELLED COMPOUNDS
Authors: Yoshida Seiichi , Towers G. H. N.
Published: October 2017

The shikimic acid (SA) content of Pinus resinosa twigs was found to range from 0.2–2.12 g fresh weight, depending on the season of the year. Of the radioactive compounds administered to cut shoots, pyruvic acid gave SA of the highest specific activity. Sugars were next most effective, with glucose and ribose being better than sucrose and fructose. Carbon from several organic acids was not readily incorporated into SA. Pyruvate-3-C14gave SA of higher specific activity than did pyruvate-1-C14or -2-C14. When pyruvate-1-C14was used, 40% of the activity in shikimic acid was in the carboxyl carbon, whereas with pyruvate-2-C14or -3-C14only 3–10% of it was in the carboxyl carbon. The results with pyruvate can best be explained in terms of the "dicarboxylate shuttle". When either erythrose or 5-dehydroshikimic acid was administered together with pyruvate-C14, a decrease in specific activity of SA was observed. These results are consistent with the view that in Pinus, SA is synthesized from phosphoenolpyruvate and erythrose-4-phosphate through dehydroshikimic acid.
ADJUSTMENTS TO CONSTANT LOW TEMPERATURES IN WHITE RATS LIVING IN GROUPS
Authors: Héroux O.
Published: October 2017

White rats, in groups of 10, were exposed for 3 months in the laboratory to constant temperatures of 19 °C or −10 °C. Grouping the animals did not alter the pattern of metabolic adaptation usually observed in individually cold-acclimated rats and recently observed in group-caged white rats exposed outdoors during the winter. This pattern of adaptation is characterized by an increased capacity for heat production, as shown by a longer survival time at −35 °C, a reduction of shivering, an increased sensitivity to noradrenaline, an increased ear vascularization, a reduction in protein and fat deposition, and an enlargement of heart, liver, and kidneys. Group-caging at constant low temperature (a) prevented the development of cold injuries and the enlargement of pituitary, thyroid, adrenals, which are usually observed in individually cold-exposed rats indoors, (b) resulted in an increased resting metabolism, normal adrenal cortex activity, and no increase in pelt insulation in contrast to that previously found in white rats grouped outdoors during the winter. These different adjustments to cold in white rats exposed to different sets of environmental conditions are compared with similar adjustments found in wild Norway rats.From these comparisons, one must conclude that many of the structural and endocrine adjustments observed in individually cold-acclimated rats in the laboratory are reactions peculiar to continuous cold stimulus, i.e. reactions to a specific set of experimental conditions rather than essential components of the fundamental mechanism for non-shivering thermogenesis.
THERMOGENESIS DUE TO EXERCISE AND COLD IN WARM- AND COLD-ACCLIMATED RATS
Authors: Hart J. S. , Jansky L.
Published: October 2017

In both warm- and cold-acclimated rats, heat production was measured while the animals were at rest and running at maximum sustained effort at temperatures from 30 °C to those giving maximum thermogenesis. In both these groups, the maximum heat production during exercise did not exceed the maximum at rest in extreme cold. Exercise substituted for shivering in warm-acclimated rats and, at temperatures below 10 °C, resulted in hypothermia. Heat derived from exercise added to nonshivering thermogenesis in cold-acclimated rats above −20 °C. Below −20 °C, exercise substituted for shivering as in warm-acclimated rats at higher temperatures, and the rats became hypothermic. Extension of the temperature range for activity by cold acclimation appears to result from development of nonshivering thermogenesis, which, unlike shivering, is not eliminated by exercise.
IMPROVED PROCEDURES FOR PREPARATION AND CHARACTERIZATION OF MYROTHECIUM CELLULASE: PART 2. PURIFICATION PROCEDURES
Authors: Whitaker D. R. , Hanson K. R. , Datta P. K.
Published: October 2017

Two methods are described for purification of the cellulase of Myrothecium verrucaria from concentrated culture filtrates. The steps of method I are (1) fractionation with ammonium sulphate, (2) elution through Sephadex G25, (3) elution through Sephadex G75, (4) precipitation with polymethacrylic acid, and (5) elution through Amberlite CG50 with citrate buffer containing a gradient of urea concentration. The steps of method II are precipitation by saturated ammonium sulphate, (2) and (4) as above, elution through DEAE-cellulose with phosphate buffer containing 7 M urea, followed by (2) and (3) as above. The two methods gave final products with identical specific activities toward carboxymethyl cellulose; the increase in specific activity was approximately 12-fold. Starch-gel electrophoresis at pH 6.8 showed no major indications of heterogeneity. The purified enzyme was unstable but could be stored frozen in dilute salt solution.Enzyme passed through DEAE-cellulose without an inhibitor of cellulase activity was contaminated by DEAE-substituted oligoglucosides and subject to proteolysis. Urea could be replaced by cellobiose as an inhibitor but the latter gave enzyme contaminated by products of transfer reactions.Binding of urea by the resin is shown to influence significantly the resolution attainable in chromatographic fractionations on Amberlite CG-50 with buffers containing gradients of urea concentration.Procedures for dialysis and desalting of cellulases and a compact reaction vessel for pH stats are described.
THE METABOLISM OF PROPIONATE BY WHEAT STEM RUST UREDOSPORES
Authors: Reisener H. , Finlayson A. J. , McConnell W. B. , Ledingham G. A.
Published: October 2017

When uredospores of wheat stem rust were shaken for 3 hours with phosphate buffer (pH 6.2) containing propionate-1-C14, -2-C14, or -3-C14, about 55% of the carbon-14 was removed from the solution. With propionate-1-C14, most of the carbon-14 taken up was released as carbon dioxide-C14, whereas about 20% and 31% of propionate carbon 2 and carbon 3, respectively, was incorporated into the spores. The specific activity of a fraction consisting of the free amino acids of a hot-alcohol and hot-water extract of the spores increased markedly with increase in the position number of propionate in which the carbon-14 was located. A similar relation was observed for other fractions such as soluble carbohydrates, ether-soluble material, organic acids, and insoluble residue from spores. The most active amino acids isolated were glutamic acid, γ-aminobutyric acid, and alanine. Partial degradations showed that with propionate-2-C14the carboxyl groups of glutamic acid were especially radioactive, whereas with propionate-3-C14the internal carbons were most radioactive.It is concluded that propionate metabolism in the rust spores involved conversion of carbon 1 to carbon dioxide, and utilization of carbons 2 and 3 as acetate with carbon 2 behaving as the carboxyl carbon.
PURIFICATION OF STAPHYLOCOCCAL β-LYSIN
Authors: Jackson A.W.
Published: October 2017

A method is described by which staphylococcal β-lysin may be purified some 250 times, with overall yields of 50–60%. The procedure consists of three steps by which impurities are removed and the lysin solution concentrated. Firstly, zinc acetate is added to ice-cold, dialyzed solutions of crude lysin followed by cold ethanol to precipitate the zinc–lysin complex. Zinc is removed by dissolving the complex in water plus chelating agent, followed by dialysis at low temperature. Secondly, the lysin is reprecipitated by formation of the water-insoluble zinc–mercuric–lysin complex and again resolved as after the first precipitation. Finally, reprecipitated lysin is further purified by chromatography, employing columns of hydroxylapatite. The final preparation was free of detectable quantities of other known hemolysins and of coagulase and phosphatase.
CHROMATOGRAPHIC SEPARATION OF ISOMERIC DINITROPHENYL DERIVATIVES OF ALPHA–EPSILON DIAMINOPIMELIC ACID
Authors: Jušić D. , Roy C. , Schocher A. J. , Watson R. W.
Published: October 2017

Null
SODIUM, POTASSIUM, NITROGEN, PHOSPHORUS, AND LIPID IN MUSCLE MITOCHONDRIA ISOLATED IN SUCROSE MEDIA OF VARYING CONCENTRATIONS
Authors: Craston A. R. , Manery J. F.
Published: October 2017

Mitochondrial pellets isolated in 0.25 M sucrose from pigeon breast muscle and washed once contained 77 ± 1.43 g water per 100 g pellet, 7.8 ± 2.0 meq K and 4.29 meq Na per kg dry weight. The Na:K ratio for mitochondria was almost 5 times that of muscle, suggesting that mitochondria might contain some of the "excess" sodium of skeletal muscle. A comparison of mitochondria isolated in three different sucrose media (0.25 M, 0.45 M, 0.88 M) was made with respect to sodium, potassium, and water concentrations of unwashed mitochondria (M1) and those washed once (M2). Washing always resulted in a loss of sodium and potassium but neither repeated washing nor suspension in hypotonic solutions removed all of the cations. These findings and the high concentration ratios observed between mitochondria and the suspension media attested to the presence of "bound" or restricted cations. A few analyses for nitrogen, phosphorus, and lipid made on the various mitochondrial preparations, on microsomal-like material, and on a "floating layer" believed to be washed out of M1preparations by resuspension, drew attention to the possibility of altering the character of the unit of reference (dry weight, mg N, etc.) used for expressing concentrations of cations. The "floating layer" was unique in being high in lipid and high in sodium. Analytical data and electron micrographs provided evidence that 0.45 M sucrose preserved the chemical and morphological integrity of the mitochondria better than the other concentrations tested.
STUDIES ON PROTEIN METABOLISM OF THE CORNEA: 1. THE DISTRIBUTION OF NITROGENOUS SOLIDS IN RABBIT CORNEAS
Authors: French R. C. , Duma Z.
Published: October 2017

The normal rabbit cornea was found to contain an average of 22.7% solids (77.3% moisture), nitrogen comprising 14.7% of the dry weight. On a dry weight basis the cornea was composed of 10% as epithelium, 87% as stroma, and 3% as endothelium plus Descemet's membrane. The solid and nitrogen content of the stroma was nearly identical with that of the whole cornea. Endothelium plus Descemet's membrane and epithelium layers were relatively low in nitrogen content (10 and 12% of the dry weight, respectively) while the epithelium was relatively high in solids (30%). The partition of nitrogen, as protein and nonprotein, soluble or insoluble in physiological saline, was estimated for each corneal layer.
CALCIUM ACCUMULATION AND RESPIRATORY ACTIVITY OF THE SMALL INTESTINE OF THE RAT
Authors: Charnock J. S.
Published: October 2017

The possible dependence of calcium accumulation upon respiratory activity of the rat small intestine has been investigated in vitro. The oxygen consumption of this tissue was relatively insensitive to the concentration of calcium in the medium; and the accumulation of radioactive calcium was greatly dependent upon ambient calcium concentration. At low concentrations of the medium the ratio of tissue calcium to that in the medium greatly exceeded unity, indicating an accumulation of this ion against a concentration gradient. However, this effect was also seen when the tissues were incubated in a gas phase of nitrogen instead of oxygen, demonstrating the lack of dependence of this process on tissue respiration. The rate at which calcium accumulated at 0° also suggests that the accumulation of calcium by the small intestine is not a metabolically controlled process but rather is a binding phenomenon similar to that reported for salivary gland of the rat.
STARCH GEL ELECTROPHORESIS OF COBRA AND RATTLESNAKE VENOMS
Authors: Neelin J. M.
Published: October 2017

The effect of pH on gradient starch gel electrophoresis of the venoms of Crotalus adamanteus and Naja flava has been examined. Sodium acetate buffer, pH 4.1, ionic strength 0.020, appeared most effective for resolution of the former venom, and acetate buffer, pH 4.7, or cacodylate buffer, pH 6.0, for the latter. Two-dimensional starch gel electrophoresis resolved at least 20 zones from the crotaline venom and 11 from the colubrid. Two zones of hemolytic activity were separated from each venom: in C. adamanteus the less cationic zone included possibly two or more acidic proteins; the corresponding zone of N. flava was more basic, more homogeneous, and more active under the conditions of assay.
URINE TITRATABLE ACIDITY AND AMMONIA EXCRETION DURING HYPOTHERMIA
Authors: Kanter G. S. , Lubinski R. H. , Shimandle D.
Published: October 2017

Hydrogen ion secretion by the kidneys of anesthetized hypothermic dogs was measured to ascertain if the hypothermic kidney helps to compensate for the acidosis which develops during exposure to cold. Artificial respiration was not used. Total hydrogen ion excretion was measured as the sum of total titratable acid and ammonia excreted. A constant saline infusion of 2 ml/min was employed to maintain a urine flow adequate for analysis procedures. Though anaerobic arterial pH, corrected to body temperature, fell significantly from 7.41 during control to 7.27 at 27 °C, urinary pH remained at control levels of approximately 6.8. Neither titratable acid nor ammonia excretion increased in response to the hypothermic acidosis as would have occurred during normothermia with a similar low pH. Total titratable acid excretion fell from a control value of 0.011 meq/min to 0.005 meq/min at 27 °C. Ammonia excretion, after a mild increase from a control value of 0.008 meq/min, fell to 0.006 meq/min at 27 °C. The failure of the hypothermic kidney to excrete additional hydrogen ions in the face of acidosis indicates that the renal acidification mechanism is temperature-dependent.
UNCOUPLING OF OXIDATIVE PHOSPHORYLATION BY IONIZING RADIATION: II. THE STABILITY OF MITOCHONDRIAL LIPIDS AND CYTOCHROMEc
Authors: Scaife J. F. , Hill B.
Published: October 2017

Mitochondria isolated from the thymus of rats or rabbits 4 hours after 800 rads of ionizing radiation show uncoupling of their oxidative phosphorylation. There are no significant differences in the contents of phospholipids, neutral lipids, or total fatty acids between normal and uncoupled mitochondria. There was no evidence of the formation of any lipid uncoupling factor in thymus mitochondria from irradiated animals.Heart or liver mitochondria isolated from animals irradiated up to 12 hours previously showed no uncoupling of oxidative phosphorylation although preparations in various media could be made with reduced cytochrome c contents. No effect of irradiation upon endogenous cytochrome c or its binding in these mitochondria could be detected.Thymus mitochondria would appear to contain very low quantities of cytochrome c (less than 0.2 μg per mg protein), yet still be tightly coupled. It is suggested that this low level may indicate a critical condition at which radiation damage could become manifest.
STUDIES OF THE CATIONIC, AND ACETYLCHOLINE, STIMULATION OF PHOSPHATE INCORPORATION INTO PHOSPHOLIPIDS IN RAT BRAIN CORTEX IN VITRO
Authors: Brossard Maurice , Quastel J. H.
Published: October 2017

The addition of 0.1 M KCl to, or the omission of CaCl2from, incubation media in which rat brain cortex slices are respiring, stimulates the incorporation of inorganic P32into phospholipids. It also stimulates the labelling of 7-minute hydrolyzable nucleotide phosphates, but decreases their levels. The stimulation of P32incorporation into total phospholipid takes place primarily into phosphatidic acid and phosphoinositide but not into phosphatidyl choline and phosphatidyl ethanolamine. The addition of succinate and γ-aminobutyrate to brain cortex slices, metabolizing glucose, markedly inhibits the labelling of phospholipids although the respiration of slices is not diminished. The potassium stimulation of phospholipid labelling only occurs if sodium ions are present in the incubation medium. The lesser stimulation due to absence of calcium ions seems, however, to be independent of the presence of sodium ions. Acetylcholine stimulation of P32incorporation into phospholipids is dependent on the presence of sodium ions. Such stimulations are suppressed by concentrations of malonate, iodoacetate, fluoride, and ethanol that have little effect on the unstimulated incorporation of P32. Atropine and hyoscine inhibit acetylcholine stimulation but not cationic stimulation of P32incorporation. It is suggested that the effect of acetylcholine on P32incorporation is mediated by cationic changes at the nerve cell membrane.
SYNTHESIS OF FATTY ACIDS BY TESTICULAR TISSUE IN VITRO
Authors: Hall Peter F. , Nishizawa Edward E. , Eik-Nes Kristen B.
Published: October 2017

The fatty acids palmitic, palmitoleic, stearic, and oleic have been isolated from rabbit testis and evidence for the synthesis of palmitic and stearic acids de novo from acetate-1-C14is presented. ICSH did not produce demonstrable stimulation of the synthesis of these acids in vitro although the hormone stimulated the production of testosterone-C14by the same tissue. Adrenal tissue was shown to contain palmitic, stearic, and oleic acids, and ACTH did not increase the incorporation of acetate-1-C14into a fatty acid fraction extracted following incubation of adrenal tissue in the presence of this substrate. Fatty acid biosynthesis, therefore, is probably not influenced by the mechanisms by which tropic hormones increase steroid formation.
MEAN FORMATION TIME OF HUMAN OSTEONS
Authors: Frost H. M.
Published: October 2017

With the aid of 19 doubly tetracycline-labelled human bones the mean daily linear decrease in the radius of Haversian canals of newly forming osteons was measured. The mean outside diameters of the Haversian canals were measured on a larger number of human bones. From these measurements the calculated mean time of Haversian system formation in ribs is 46±37 days at age 7 years and 79±63 days at age 43. Compared with those for ribs, the formation times seem to be longer in the long bones of the appendicular skeleton.
DETERMINATION BY THIN-LAYER CHROMATOGRAPHY OF URINARY HOMOVANILLIC ACID IN NORMAL AND DISEASE STATES
Authors: Sankoff Irwin , Sourkes T. L.
Published: October 2017

A rapid method using thin-layer chromatography has been developed to measure urinary HVA (homovanillic acid). Ethyl acetate extracts of urine are chromatographed on glass plates coated with silica gel. The solvent used is the organic phase of benzene: acetic acid: water (2:3:1) mixture. The eluted HVA is treated with Folin's phenol reagent and absorbance is measured at 750 mμ in a spectrophotometer. Normal amounts of HVA in human urine are 8.23 ± 2.96 (mean ± standard deviation) mg/24 hours or 6.42 ± 2.28 mg/g of creatinine. Higher values were obtained in cases of ganglioneuroma and neuroblastoma, in a case of pheochromocytoma, and in one of two cases of hepatolenticular degeneration (Wilson's disease). In three cases of Huntington's chorea, values lay in the normal range.
HYDROLYSIS OF CALF THYMUS DEOXYRIBONUCLEATE BY PANCREATIC DEOXYRIBONUCLEASE: II. ISOLATION AND ANALYSIS OF THE MONONUCLEOTIDES AND DINUCLEOTIDES OBTAINED BY ENZYMIC DEGRADATION IN THE PRESENCE OF MANGANOUS IONS
Authors: Becking G. C. , Hurst R. O.
Published: October 2017

Analysis of the oligonucleotides produced by the exhaustive hydrolysis of calf thymus DNA by pancreatic DNAase in the presence of manganous ions at pH 6.6 shows an increase in the concentration of mononucleotides and dinucleotides which are found to comprise 5% and 49% of the total nucleotide phosphorus. The relative amounts of the isomeric dinucleotides formed during manganous ion activation of the enzyme differ from those obtained for magnesium ion activation. The results are interpreted as indicating a random attack by the enzyme at multiple points in an endonuclease action with certain linkages being more susceptible than others. The evidence suggests that the pPu–pPu linkage is stable and that the increased liberation of purine nucleotides occupying the 5′-terminal phosphate position is due to hydrolysis of pPy–pPu linkages.
THE EFFECT OF PIG PITUITARY ACTH FRACTIONS ON DIFFERENT PARAMETERS OF ADRENOCORTICAL ACTIVITY
Authors: Jager E. de , Homan J. D. H. , Wied D. de
Published: October 2017

Purified unhydrolyzed corticotrophin was separated into five fractions by chromatography on a column of carboxymethyl cellulose, using pyridine – acetic acid as a buffer system. These fractions were biologically assayed by means of the in vitro technique of Saffran and Schally, the adrenal ascorbic acid depletion test of Sayers et al., and an assay based on the increase of plasma corticosterone levels in hypophysectomized rats. In the in vivo assays both the intravenous and subcutaneous routes of injection were applied.The principal aim of this study was to investigate for each separate fraction the extent to which the potencies according to the Sayers test correspond with the potencies obtained by the plasma corticosterone method. When comparing results found after identical routes of injection, a fair agreement was observed for those fractions showing electrophoretic relationship and together accounting for the major part of the biological activity of the starting material. However, the minor fractions showed significant differences.These findings are discussed together with the results of the classical assay methods and their deviations from data reported in the literature.
NUCLEIC ACID METABOLISM IN INTESTINAL MUCOSA: III. LOSS OF NUCLEIC ACIDS FROM INTESTINAL MUCOSA OF THE RAT DURING INCUBATION IN VITRO
Authors: Stewart Beryl E. , Zbarsky S. H.
Published: October 2017

Null
EFFECT OF IONIZING RADIATION ON THE OXIDATION OF SUCCINATE BY RAT THYMUS MITOCHONDRIA
Authors: Scaife J. F.
Published: October 2017

Null
DEOXYRIBONUCLEIC ACID DEPENDENT RIBONUCLEIC ACID SYNTHESIS IN THE CROWN-GALL TUMOR-INDUCING ORGANISM AGROBACTERIUM TUMEFACIENS
Authors: Hochster R. M. , Chang V. M.
Published: October 2017

The enzyme RNA polymerase has been partially purified from cell-free extracts of the crown-gall tumor-inducing organism Agrobacterium tumefaciens. The four triphosphates ATP, CTP, GTP, and UTP, manganese (or magnesium) ions, and DNA are all required for activity. DNA acts as a template in the formation of the new RNA molecule the base composition of which exactly mimics that of the particular DNA used. The dependence of the reaction on time, pH, and on the concentrations of nucleoside triphosphate, DNA, and protein has been worked out. The exact requirements of the entire system are delineated, the effect of physical alteration of the DNA used (heating, cooling, sonic oscillation) has been examined and a new observation made on the stimulation of DNA action by 1-minute sonic pretreatment.Actinomycin D is shown to inhibit the reaction completely at 2.8 × 10−5 M while atabrine, a new inhibitor, requires a concentration of 3.3 × 10−3 M under the conditions specified. Hydrolysis of the reaction product by means of a variety of procedures and other information obtained show that the reaction product is, indeed, RNA.The data reported herein are regarded as providing a satisfactory explanation for the mechanism of biosynthesis of at least one type of RNA (presumably "messenger" RNA) in A. tumefaciens.
ACTION OF ORGANOPHOSPHORUS COMPOUNDS UPON ESTERASES OF HUMAN LIVER
Authors: Ecobichon D. J. , Kalow W.
Published: October 2017

Human serum and liver esterases separated electrophoretically in starch gel were exposed to two series of organophosphorus insecticides. One series consisted of compounds active per se, the other of analogues requiring metabolic or chemical conversion to produce potent anticholinesterases. The results indicated that only one fraction of the liver, designated as zone L-2, is inhibited by low concentrations of all insecticides. This fraction shows a similar pattern of susceptibility to different inhibitors as does human serum cholinesterase. Of the other two zones of activity in liver, zone L-1 was found to be more susceptible to activated thionate, dithioate, and thioether derivatives than was zone L-3, while the latter zone was more susceptible to phosphates active per se.
THE EFFECT OF 4-METHYLTROPOLONE ON THE METABOLISM OF ADRENALINE
Authors: Mavrides C. , Missala K. , D'Iorio A.
Published: October 2017

The inhibiting effects of 4-methyltropolone have been tested in a partially purified preparation of O-methyltransferase from rat liver. The inhibition observed was of a strictly competitive nature whether the enzyme was or was not preincubated with the inhibitor. Addition of the substrate partially reversed the inhibition.The injection of C14-labelled adrenaline in rats pretreated with 4-methyltropolone (30 mg/kg) clearly indicated a decreased excretion of labelled metanephrine.
FACTORS INFLUENCING THE NUTRITIONAL VALUE OF FISH FLOUR: III. FURTHER STUDIES ON AVAILABILITY OF AMINO ACIDS
Authors: Morrison A. B.
Published: October 2017

Weight gains of male weanling rats given fish flour sample X were significantly increased by addition to the diet of methionine, histidine, threonine, and tryptophan. When histidine or methionine were omitted from the amino acid mixture, weight gains were similar to those found with the unsupplemented flour, and the combination of methionine and histidine was as effective as the four amino acids. Supplements of histidine and methionine had no effect on weight gains of rats given fish flour sample CFF, which was of high nutritional value. Sample X contained methionine in an amount similar to that of sample CFF, and somewhat less histidine. The amounts of methionine and histidine released during in vitro digestion with pancreatin were much less for sample X than for sample CFF. Steaming sample X for 30 minutes significantly increased its gross protein value determined in a methionine-deficient diet, but had no effect on the total or organic chloride content. It was concluded that sample X contained unavailable methionine and histidine.
A CONJUGATED FORM OF AMINOPEPTIDASE FROM AUTOLYZED EXTRACTS OF KIDNEY TISSUE
Authors: Matheson A. T. , Bjerre S. , Hanes C. S.
Published: October 2017

Peptidase-rich fractions were prepared from autolyzed extracts of pig kidney. These preparations showed many properties in common with leucine aminopeptidase but exhibited remarkable stability when subjected to vigorous emulsification with chloroform–octanol. By chromatography on DEAE-cellulose and on Sephadex gel under appropriate conditions, it was demonstrated that the aminopeptidase in these preparations exists in a conjugated form which is dissociable into an enzymatically-active protein moiety and inactive fractions containing nucleic acid. The dissociated form of the enzyme is extremely labile and shows an A[280/260] ratio of 1.2. Starch gel electrophoresis of the purified enzyme fraction shows several enzymatically-active protein bands and only traces of inactive protein. Preliminary evidence suggests that the aminopeptidase present in the supernatant fraction of non-autolyzed homogenates of kidney tissue exists also in a protected conjugated form.
DDT AND THE METABOLISM OF VITAMIN A AND CAROTENE IN THE RAT
Authors: Phillips W. E. J.
Published: October 2017

The utilization of vitamin A and carotene has been studied in the rat following the feeding of DDT in the diet over a range of concentrations from 0 to 100 p.p.m. for periods up to 72 days. In two of three experiments, the feeding of over 10 p.p.m. DDT decreased the utilization of orally administered carotene. In two experiments, the feeding of 10 p.p.m. DDT or over decreased liver storage of vitamin A when vitamin A per se was administered. The storage of vitamin A was similarly reduced when a diet containing both DDT and carotene or DDT and vitamin A was fed.
INVESTIGATIONS INTO THE MECHANISM OF DEXTRAN-INDUCED EDEMA IN RATS
Authors: Gözsy B. , Kátó L.
Published: October 2017

In the rat, intravenous injection of minute amounts (7.9 mg/kg) of dextran induced edema formation of the same intensity as high doses (300–600 mg/kg). With the high doses, mast-cell disruption (histamine and serotonin release), vasodilatation, hypothermia, hypotension, hemoconcentration, and edema occurred. Since minute doses of dextran induced only vasodilatation and edema formation, this response is considered as the pure anaphylactoid reaction. The syndrome provoked by high doses is a consequence of conditions created by the physical presence of large quantities of dextran in the blood, rather than an integral part of the proper anaphylactoid sequence. Minute doses of dextran induced edema without mast-cell disruption, hypothermia, hypotension, or hemoconcentration, thus showing that the dextran response in the rat is mediated by factors other than histamine and serotonin of mast-cell origin.
FORMATION OF OIL IN THE SEED OF RICINUS COMMUNIS L.
Authors: Canvin David T.
Published: October 2017

Castor seeds were collected at 3- and 6-day intervals after blossoming until maturity. The seeds were analyzed for protein and oil content and the fatty acid composition of the oil was determined by gas–liquid chromatography. Oil formation began 21 days after blossoming and two-thirds of the oil was synthesized in the next 20 days; the remaining one-third was formed in the last 20-day period. Protein synthesis occurred over a longer period of time but was accelerated during the middle 20-day period.Ricinoleic acid, the characteristic component of castor oil, was not present in the very young seed, but appeared when the seed was 12 days old and represented 90% of the fatty acids when the seed was 36 days old. After this time the fatty acid composition of the oil remained constant and characteristic. In the intervening 24-day period, the amount of ricinoleic acid was lower than normal. The amount of each fatty acid component, expressed on a per seed basis, increased over the entire period of development and there was no evidence of substantial conversion of oleic or linoleic acid to ricinoleic acid.
THE ROLE OF A HUMORAL MECHANISM IN THE CARDIOVASCULAR ADJUSTMENTS OVER A PROLONGED PERIOD FOLLOWING THE PRODUCTION OF ACUTE EXCHANGE ANAEMIA
Authors: Hatcher J. Donald , Jennings Donald B. , Parker John O. , Garvock William B.
Published: October 2017

Cardiovascular measurements were made in groups of anaesthetized dogs at 1 and 3 hours and 2, 3, 4, 6–7 and 8–9 days after the rapid production of severe anaemia by dextran-for-blood exchange. At 1 and 3 hours after exchange the cardiac output was increased, fell to be at or close to control levels at 2 and 3 days, then rose again at 4 to 9 days after exchange. An increased percent extraction of arterial oxygen was present throughout, being greatest at the 2- to 3-day period. These mechanisms were responsible for maintaining the tissue demands for oxygen but these demands as evidenced by oxygen consumption were reduced below control levels at 1 and 3 hours after exchange, rose to control at 2 and 3 days, then increased above control at 4 to 9 days after exchange.Assays were carried out with blood from anaemic dogs at all periods for a cardiotonic agent, previously demonstrated in the blood of anaemic dogs, which induced cardiovascular changes in normal assay dogs comparable to those of the hyperkinetic circulatory state in anaemia. This material is absent from normal blood. The cardiotonic agent was present at 3 hours and at 3 to 9 days in maximal amounts. There was no cardiotonic agent detected at 1 hour and only a moderate amount was present at 2 days after exchange.Delineation of the exact role of the cardiotonic agent in the cardiovascular adjustments in anaemia requires further investigation, in particular of certain discrepancies which exist between the levels of cardiotonic agent and the circulatory changes in the anaemic animal.
SKIN HEPARIN LEVELS AND POSTHEPARIN PLASMA CLEARING FACTOR LIPASE LEVELS IN IRRADIATED ADRENALECTOMIZED AND CORTISONE-TREATED RATS
Authors: Monkhouse Frank C. , Baker Donald G.
Published: October 2017

Experiments were carried out to determine whether changes in endogenous heparin in rat tissues were related to changes in plasma levels of clearing factor lipase (CFL). Skin heparin levels, postheparin plasma CFL levels, and peritoneal mast cell counts were measured in normal, adrenalectomized, cortisone-treated, and X-irradiated rats. Total body X-irradiation in doses of 400 r to 600 r decreased skin heparin levels. The postheparin CFL levels of irradiated rats remained high while that of pair-fed controls dropped significantly. Cortisone treatment for 6 days caused an increase in plasma CFL levels in both intact and adrenalectomized rats but no significant change in skin heparin levels or mast cell count. Adrenalectomy caused no significant change in either postheparin CFL or skin heparin levels.
GLYCOLYTIC ENZYMES IN THE TISSUES OF A SALMONOID FISH (SALMO GAIRDNERII GAIRDNERII)
Authors: MacLeod Robert A. , Jonas R. E. E. , Roberts E.
Published: October 2017

Glycolysis in various tissues of the steelhead trout (Salmo gairdnerii gairdnerii) has been studied in vitro using tissue extracts and homogenates. Of the tissues examined, skeletal muscle, heart muscle, liver and kidney, only heart muscle homogenate was found to be capable of converting free glucose to lactic acid without added hexokinase. Low hexokinase activity or low hexokinase activity coupled with adenosine triphosphatase activity accounted for the failure of the other tissue homogenates to attack glucose.Qualitative and quantitative studies have indicated the presence of hexokinase, phosphoglucoisomerase, phosphofructokinase, aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglyceromutase, enolase, pyruvic kinase, and lactic dehydrogenase in the various fish tissues examined. Except for hexokinase and phosphofructokinase, the activities of the glycolytic enzymes of skeletal muscle were found to be 10 to 100 times greater than those of the same enzymes in the other tissues tested.Diphosphopyridine nucleotide (DPN) and adenosine diphosphopyridine (ADP) were cofactors and iodoacetate and fluoride plus phosphate inhibitors of enzymes of the fish glycolytic systems.It can be concluded from this study that the Embden–Meyerhof glycolytic pathway functions in tissues of the anadromous salmonoid S. gairdnerii gairdnerii.
STUDIES ON THE ACYLATION OF LYSOLECITHINS
Authors: Tattrie N. H. , Bennett J. R.
Published: October 2017

"Semi-synthetic" lecithins were prepared by the acylation of lysolecithin cadmium chloride complexes (the lysolecithins were produced from egg lecithin by hydrolysis with phospholipase A) in the presence of pyridine with 1-C14myristoyl chloride. The labelled lecithins were hydrolyzed with phospholipase A to yield free fatty acids (94% of the label) and lysolecithins (6% of the label). However, when lysolecithins were enzymically acylated with 1-C14linoleic acid and the resulting labelled lecithins cleaved with phospholipase A, no labelled fatty acid was detected in the lysolecithin fraction.Labelled lecithins were also enzymically synthesized with 1-C14linoleic acid and lysolecithins prepared from egg lecithin by reaction with sodium methoxide. The labelled lecithins were hydrolyzed with phospholipase A and the labelled lysolecithins were isolated and reacylated enzymically with oleic acid. The hydrolysis of these lecithins with phospholipase A showed that the lysolecithins retained all the label.
APPARATUS FOR THE PREPARATION OF HIGHLY PURIFIED WATER SUITABLE FOR TRACE METAL ANALYSIS
Authors: Holt John M. , Lux Walter , Valberg Leslie S.
Published: October 2017

Null
URINARY AND FECAL CONVERSION PRODUCTS OF 16-OXOESTRADIOL-17β-16-C14IN THE DOMESTIC FOWL
Authors: Ainsworth L. , Common R. H.
Published: October 2017

16-Oxoestradiol-17β-16-C14was injected intravenously into non-laying hens and the urine and feces for succeeding days were collected separately. Estrogen extracts were prepared using enzymic hydrolysis. Analyses of the urinary phenolic fractions showed the presence of two major radioactive products and one minor radioactive product. The major products were identified as 16-oxoestradiol-17β and 16-epiestriol. The minor product was not identified, but it contained little if any radioactive estriol. The fecal phenolic fraction contained a radioactive material identified as 16-epiestriol. A summary of recoveries and distributions of the radioactivity is presented along with criteria for the radiochemical purities of the isolated steroids.
PARTIAL PURIFICATION AND PROPERTIES OF PROLYL-RNA SYNTHETASE OF RAT LIVER
Authors: Fraser M. J. , Klass D. B.
Published: October 2017

Prolyl-RNA (prolyl ribonucleic acid) synthetase has been purified 30-fold from a 105,000 × g supernatant of a rat liver homogenate by precipitation at pH 5.0, heat treatment at 55 °C for 3.0 minutes in the presence of 1.0 mM ATP (adenosine triphosphate), and by ammonium sulphate fractionation. The enzyme catalyzed proline-dependent ATP-32PP (PP, inorganic pyrophosphate) exchange and the formation of prolyl hydroxamate and of prolyl-RNA. Although the enzyme did not catalyze the formation of hydroxyprolyl-RNA, it catalyzed a slight hydroxyproline-dependent ATP-32PP exchange and the formation of a small amount of hydroxyprolyl hydroxamate which was much less than the amount of prolyl hydroxamate formed under the same conditions. The enzyme is thus not quite specific for proline activation, but is specific for amino acyl-RNA formation. It is probably concerned in protein biosynthesis.In the proline-dependent ATP-32PP exchange reaction the enzyme showed optimum activity in the pH range 6.2–8.2 and no activity at pH 5.0. The apparent Kmfor proline in this reaction was found to be 0.43 mM. Mg++was required for activity. Prolyl-RNA formation was optimal at pH 8.0. The apparent Kmfor proline in this reaction was found to be 2.5 μM. The effects of some proline analogues on proline activation were studied. Hydroxyproline and thioproline were found to inhibit both proline-dependent ATP-32PP exchange and prolyl-RNA formation. Thioproline was a competitive inhibitor of the exchange reaction and showed a KIof 0.95 mM. Pyrrolidone carboxylate had no appreciable effect on proline activation.
AEROBIC GLYCOLYSIS OF X-IRRADIATED THYMOCYTES
Authors: Araki Kimiko , Myers D. K.
Published: October 2017

The aerobic lactate production of rat thymocyte suspensions incubated at 37 °C for 2 hours was doubled following exposure to approximately 70 r X-radiation. Lower doses down to 18 r also produced a significant increase in aerobic lactate production. Increased lactate accumulation following exposure to 1000 r was observed after incubation for as little as 30–60 minutes, though the rate of accumulation increased still further between 2 and 4 hours incubation. A decrease in pH or temperature during incubation of irradiated thymocyte suspensions minimized the lactic acid accumulation. A comparison of the effects of X-irradiation in different media and of the effects of several metabolic inhibitors suggested that the increase in aerobic lactate production was a sensitive indicator of cell damage associated with the loss of intracellular potassium ions.Respiration and anaerobic glycolysis of the thymus cells were both much less sensitive than aerobic glycolysis to the effects of X-irradiation. The "anaerobic" lactate production of rat thymocyte suspensions in the presence of dinitrophenol was reduced by 50% after exposure to 5000–6000 r of X-radiation.
MECHANICAL PROPERTIES AND HISTAMINE AND SEROTONIN CONTENT OF GUINEA PIG LUNGS AS INFLUENCED BY MICROPARTICLES INHALATION
Authors: Robillard Eugène , Alarie Yves
Published: October 2017

In previous experiments, the inhalation of aluminum or iron oxide submicronic particles was shown to possess strong constricting properties, using the method of volume–pressure curves with atelectatic guinea pig lung. The constricting effect of aluminum was prevented by cyproheptadine, an antihistaminic and antiserotonin substance. In the present experiments, determinations of serotonin and histamine in dust-treated lungs were undertaken; the content of serotonin and of histamine was found to be increased after aluminum and after iron oxide particle inhalation respectively. Serotonin and histamine given as aerosols to guinea pigs reproduced the characteristic volume–pressure curves obtained after aluminum or iron oxide microparticle inhalation, respectively.
PHOSPHORUS METABOLISM IN COLD-EXPOSED RATS
Authors: Beaton John R.
Published: October 2017

Male rats weighing 207 ± 2.38 g were exposed to cold (2–3 °C) for a period of 7 days during which urine and faeces were collected daily and analyzed for phosphorus. As a consequence of cold exposure, urinary excretion of phosphorus is increased. With free access to food, the increased food (and hence phosphorus) intake of the animals compensates for the increased urinary excretion and a normal phosphorus balance results. Cold exposure was without significant effect upon blood concentrations of acid-soluble, inorganic, organic, or lipid phosphorus. Increased inorganic and decreased organic, non-lipid phosphorus levels were observed in livers of cold-exposed rats. These observations suggest the breakdown of organic phosphates (e.g. hexose and triose phosphates, adenosine phosphates, phosphocreatine) to inorganic phosphorus.
SEPARATE RENAL FUNCTION STUDIES IN DOGS WITH CHRONIC UNILATERAL RENAL ARTERY OBSTRUCTION: THE EFFECT OF HYPERTONIC UREA INFUSIONS
Authors: Rapoport A. , Wilson D. R. , Ranking G. N. , White L. W. , Rudd W. W. H.
Published: October 2017

The left main renal artery was constricted in 41 dogs for intervals of 7 to 30 days. Separate urine collections from each kidney were then made during water diuresis and, in 28 of the dogs, during hypertonic urea diuresis.The most sensitive criteria of renal artery obstruction were combinations of urine volume and creatinine concentration ratios or of sodium and creatinine concentration ratios.To demonstrate enhanced water reabsorption by the tubules of a kidney, there is no diagnostic advantage in the use of any one over another of the ratios of urine creatinine, urea, or para-amino hippurate.The filtration fraction of the constricted kidney was the same as that of the control. Thus the simpler measurement of each kidney's endogenous creatinine clearance offers the same assessment of relative kidney function as the technically more difficult measurement of separate para-amino hippurate clearances.When, under water diuresis, the urine concentration ratios of sodium and creatinine, as well as the urine volume ratio, are diagnostic, then urea infusions tend to blunt them. Conversely, when these ratios are not diagnostic, urea infusions tend to enhance them. Thus, for the greatest efficiency in the diagnosis of renal artery obstruction, separate urine collections should be made under conditions of both water and hypertonic urea diuresis.
FORMATION OF UREA IN LIVER HOMOGENATES FROM CITRULLINE AND VARIOUS N-ALKYL DERIVATIVES OF ASPARTIG ACID
Authors: Charbonneau R. , Berlinguet L.
Published: October 2017

The effects of various N-alkylated derivatives of aspartic acid on the synthesis of urea by rat liver homogenates have been studied. At 5 × 10−3 M concentration, N-methyl, N-ethyl, N-isopropyl, and N-cyclohexyl aspartic acids are not utilized and have no effect on the formation of urea. At this concentration, N-allyl-DL-aspartic acid inhibits the formation of endogenous urea by 77%. At concentrations of 2.5 to 7.5 × 10−2 M, N-methyl, N-ethyl, and N-isopropyl aspartic acids slightly increase the formation of endogenous urea; this is about 15% of the value obtained when aspartic acid alone is added at the same concentration. In the case of simple N-alkylated aspartic acids, liver homogenates are able to cleave the alkylated chain with the result that a small amount of urea synthesis is possible. N-allylaspartic acid totally inhibits the formation of urea from aspartic acid at a relatively low concentration of 6.2 × 10−3 M. N-cyclohexylaspartic acid has also an inhibitory effect which is ten times less pronounced than that of the N-allyl derivative.Natural amino acids such as DL- and L-valine, DL- and L-leucine, DL- and L-lysine, DL-alanine and glycine, at concentrations of 1.2 to 5 × 10−2 M, also inhibit the formation of urea. This inhibition is probably due to the fact that other metabolic pathways, used by these amino acids, have priority over the formation of urea. Amino acid analogues, such as 1-aminocyclopentane carboxylic acid and 1-amino-2-methylcyclopentane-carboxylic acid, do not have any effect on the synthesis of urea.A free amino group in the aspartic acid molecule seems to be essential for the synthesis of argininosuccinic acid.
USE OF I125-LABELED 5-IODO-2′-DEOXYURIDINE FOR THE MEASUREMENT OF DNA SYNTHESIS IN MAMMALIAN CELLS IN VITRO
Authors: Mak S. , Till J. E.
Published: October 2017

The use of isotopically labeled 5-iodo-2′-deoxyuridine (I125UdR) for determination of the rate of deoxyribonucleic acid synthesis in mammalian cells in vitro has been investigated. The results obtained indicate that for this purpose I125UdR is a suitable substitute for the more commonly used DNA precursor, tritium-labeled thymidine (H3TdR). I125UdR appears to be incorporated specifically into the DNA of cells in culture, and has been demonstrated to compete with H3TdR, although the Kmfor H3TdR was smaller than that of I125UdR by a factor of approximately 4. The amount of label incorporated into DNA of cells increased linearly with time. When the rate of DNA synthesis was reduced by exposure of the cells to various doses of X-rays, the ratio of I125UdR incorporation to H3TdR incorporation into DNA of cells was found to be a constant, which supports the view that uptake of the analogue provides as reliable an indication of effects upon the rate of DNA synthesis as does that of H3TdR. The chief advantage of I125UdR over H3TdR is that I125is a gamma emitter, so that the difficulties encountered in detection of the low energy beta particles from H3may be avoided.