bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF THE TYPE AND AMOUNT OF DIETARY FAT ON THE LEVEL OF PLASMA TRIGLYCERIDES IN HUMAN SUBJECTS IN THE POSTABSORPTIVE STATE
Authors: Beveridge J. M. R. , Jagannathan S. N. , Connell W. Ford
Published: December 2009

Fifty-eight healthy university students consumed homogenized formula diets for 16 days, and plasma triglycerides were determined on samples of blood obtained from the subjects in the fasting state at days 0, 4, 8, 12, and 16. On a fat-free (high-carbohydrate) diet there was a sex difference in the response, with a group of 11 males showing a highly significant increase (over twofold) and a group of 14 females showing no significant change. No change was observed in 10 male subjects transferred from their free-choice diet to a formula diet providing 45% of calories from butterfat. However, in the case of a group of 23 men who consumed a diet similarly high in corn oil, a significant decrease occurred and the values observed were also significantly lower than those obtained on the butterfat ration. The usual responses of the plasma cholesterol to these diets were observed. Although a parallelism was observed between the behavior of the plasma triglycerides and plasma cholesterol on diets containing fat, there was a divergence on the fat-free diet, characterized by an increase in plasma triglycerides in the males and no change in the females, whereas the usual decrease in plasma cholesterol occurred in both sexes.
THE VENOM OF THE MUD-DAUBER WASP: II. SCELIPHRON CAEMENTARIUM: PROTEIN CONTENT
Authors: Rosenbrook Jr. Wm. , O'Connor Rod
Published: December 2009

Gel filtration of Sceliphron caementarium venom, obtained by electrical excitation, has shown an unexpectedly small protein fraction of the dried venom. Disc electrophoresis was used to separate five venom proteins, none of which possess an antigenic character in common with wasp, yellow jacket, hornet, or honeybee venoms. Disc electrophoresis of venom and of venom sac extracts demonstrated the presence in the latter of proteins not in the venom itself.
PHYSICAL PROPERTIES OF COMMERCIAL BILIRUBINS
Authors: Newbold Brian T. , LeBlanc Sister Gilberte
Published: December 2009

Some physical properties, such as color, melting point, moisture content, loss in weight on heating, solubility, and extinction coefficients, of five commercially available bilirubins have been determined and compared. The visible and infrared absorption spectra of the bilirubins also were recorded and are discussed.
THE COMPETITIVE INHIBITION OF THE CYTOPLASMICL-α-GLYCEROPHOSPHATE DEHYDROGENASE OF SKELETAL MUSCLE BYL-α-GLYCEROPHOSPHATE
Authors: Blanchaer M. C.
Published: December 2009

The inhibition by L-α-glycerophosphate of the reduction of dihydroxyacetone phosphate by crystalline rabbit muscle NAD+-linked L-α-glycerophosphate dehydrogenase has been examined. As a result of the measurement of the absorbance at 340 mμ in a photometric test system at 26° containing 0.08–2.0 mM dihydroxyacetone phosphate, 0.14 mM NADH, and 1–1.5 μg crystalline enzyme in 1.5 ml 10 mM EDTA −0.1 M phosphate buffer at pH 7-0, the apparent Michaelis constant (Km) for dihydroxyacetone phosphate was found to be 0.363 mM (± 0.025 S.E.). L-α-Giycerophosphate, but not D-α-glycerophosphate, acted as a competitive inhibitor in this system with an apparent inhibition constant (Ki) of 0.575 mM (± 0.030). Substitution of 50 mM triethanolarnine buffer for the 0.1 M phosphate buffer lowered the Kmto 0.088 mM (± 0.019) and the Kito 0.240 mM (± 0.013). To study the enzyme at lower NADH concentrations, a fluorometric system containing 20–75 μM NADH, 5–370 μM DHAP, and 0.5–2.0 μg enzyme in 1 ml 2 mM EDTA −50 mM triethanolarnine buffer, pH 7.0 at 23°, was used. The apparent Kmfor dihydroxyacetone phosphate and Kifor L-α-glycerophosphate were 0.075 μM (± 0.020) and 0.186 mM (± 0.006) respectively, at a NADH concentration of 75 μM. Lowering the NADH concentration to 20 μM further decreased the apparent Kmand Kivalues to 0.039 mM (± 0.008) and 0.056 mM (± 0.007) respectively.A consideration of the concentrations of dihydroxyacetone phosphate and L-α-glycerophosphate in muscle during contraction suggests that the competitive inhibition of cytoplasmic L-α-glycerophosphate dehydrogenase by its product, L-α-glycerophosphate, may influence the pathway of triose phosphate utilization and also the coupling, by way of the L-α-glycerophosphate cycle, of cytoplasmic NADH-generating reactions to the mitochondrial respiratory chain.
FACTORS INFLUENCING THE NUTRITIONAL VALUE OF FISH FLOUR: IV. REACTION BETWEEN 1,2-DICHLOROETHANE AND PROTEIN
Authors: Morrison A. B. , Munro I. C.
Published: December 2009

Extraction of freeze-dried cod fillets with 1,2-dichloroethane resulted in destruction of cystine and histidine and in interference with the release of cystine, histidine, and methionine by pancreatic digestion. The reaction was pH dependent, occurring most readily under slightly alkaline conditions. The thioether S,S′-ethylenebiscysteine was synthesized by reacting cysteine and 1,2-dichloroethane. Alkylation of reduced wool or fish solids, and subsequent hydrolysis, yielded a sulfur-containing compound with the same Rfvalue as the synthetic thioether. The thioether appeared devoid of biological activity for L. mesenteraides P-60, Tetrahymena pyriformis W., and the rat. It was cleaved by autoclaving, but was stable to acid hydrolysis.The evidence suggested that sulfhydryl groups of protein can be alkylated by 1,2-dichloroethane to produce thioether linkages, with a resultant decrease in nutritional value.
OROTIDINE-5′-PHOSPHATE PYROPHOSPHORYLASE OF WHEAT EMBRYOS
Authors: Kapoor M. , Waygood E. R.
Published: December 2009

Orotidine-5′-phosphate pyrophosphorylase was isolated from wheat embryos and purified 35-fold. The enzyme is inhibited by high concentrations of orotate. Cu++and Mn++ions can replace the Mg++ion requirement. The enzyme shows a primary and secondary optimum at pH 8.5 and 9.8. Dihydro-orotate:NAD dehydrogenase also was demonstrated in extracts of wheat embryos, but there was no evidence for an orotate decarboxylase. Embryo homogenates incubated with orotate-6-C14formed measurable amounts of radioactive OMP and UMP, which were increased in the presence of P-ribosyl-PP but were decreased by the addition of benzimidazole.
GAS CHROMATOGRAPHIC METHOD FOR THE SEPARATION AND ESTIMATION OF AMINO ACID DERIVATIVES
Authors: Hagen P. B. , Black W.
Published: December 2009

It has been possible to prepare the N-trifluoroacetyl methyl esters of the 19 amino acids commonly found in proteins and to separate them by gas chromatography on two types of column, Carbowax 1540 and Carbowax 20M. There is a constant relation between the amount of each amino acid and the size of the recorded peak. This indicates either that the conversion to the derivative is quantitative or that a constant proportion of each amino acid is converted to its N-trifluoroacetyl methyl ester.
THE PREPARATION AND PROPERTIES OF THE POTASSIUM SKATOLYL SULFATES (THE "SULFATOXYSKATOLES")
Authors: Heacock R. A. , Hutzinger O.
Published: December 2009

The four isomeric potassium skatolyl sulfates, with the sulfate residue attached to the 4-, 5-, 6-, and 7-positions in the benzene moiety of the skatole molecule, have been synthesized. The four isomers were prepared by the sulfation of the corresponding hydroxyskatoles with either (a) the pyridine – sulfur trioxide complex in pyridine or (b) chlorosulfonic acid in pyridine. The ultraviolet spectroscopy of this group of compounds is discussed together with their paper chromatographic behavior in several different solvent systems.
IMPAIRMENT OF TRIGLYCERIDE TRANSPORT FROM THE LIVER IN CHOLINE DEFICIENCY
Authors: Haines D. S. M. , Mookerjea Sailen
Published: December 2009

The changes in liver and plasma lipids in choline deficiency were studied in vivo and in vitro. In choline deficiency, after a lag period of several days, total liver lipids rose rapidly and a relatively small decrease of plasma triglycerides was noted at about the same time. In the recovery experiments, a significant increase of plasma phospholipids occurred within 24 hours after choline had been restored to the diet of the deficient animals.When livers from normal rats (choline-supplemented) were perfused with blood diluted with buffer, triglyceride was released to the perfusate. Livers from choline-deficient rats (perfused with blood from similar deficient rats) failed to make a net contribution of triglyceride to the perfusate. A moderate recovery of transport of triglyceride from liver to plasma occurred within 4 to 7 days after choline had been restored to the diet of rats that had been fed the deficient diet for 3 weeks. These studies provided firm support for the hypothesis that, in choline deficiency, transport of triglyceride from the liver is impaired.
PHOSPHOLIPIDS: I. STUDIES ON THE THROMBOPLASTIC AND ANTICLOTTING ACTIVITY OF PHOSPHOLIPIDS
Authors: Grisdale P. J. , Okany A.
Published: December 2009

Preparative thin-layer chromatography, combined with published procedures, has facilitated the isolation of chromatographically homogeneous phosphatidylserine, phosphatidylethanolamine, and lysophosphatidylethanolamine. The effect of these compounds and their mixtures on blood coagulation has been studied in the thromboplastin-generation test. Evidence is produced to demonstrate that the results of such tests for anticlotting activity are dependent on the choice of a standard clotting agent.
THE SECONDARY ANTIBODY RESPONSE IN TISSUE CULTURE: I. OBSERVATIONS ON PROLONGED ANTIBODY SYNTHESIS BY LYMPH NODE FRAGMENTS IN MEDIA OF DIFFERENT COMPOSITION
Authors: Juhasz A. , Rose B.
Published: December 2009

Lymph node fragments obtained from rabbits immunized 4–9 months previously were cultured in Eagle's medium supplemented with normal rabbit serum or with serine. Upon secondary stimulation with the specific antigen (rat albumin) in vitro, antibody production which lasted over 4 weeks was observed. A difference in the course of antibody synthesis was established in the two different media. In the presence of normal rabbit serum, peak titers of antibody were reached 7–13 days after secondary stimulation, while, in the presence of serine, highest titers were observed on days 13–19. Furthermore, antibody titers diminished faster in the normal rabbit serum cultures as compared to those in the serine cultures. If hydrocortisone was added to culture media containing serine, antibody production by the lymph node fragments followed a pattern similar to that for cultures containing normal rabbit serum. The possible significance of these findings is discussed.
ACTIVE GLUCOSE UPTAKE BY STRIPS OF GUINEA PIG INTESTINE; COMPETITIVE INHIBITION BY PHLORHIZIN AND PHLORETIN
Authors: Sahagian B. M.
Published: December 2009

The active uptake of glucose has been demonstrated using the modified form of the intact-strip method in the golden hamster and guinea pig intestine. Accumulation of glucose by guinea pig intestine reaches a steady-state level within 90 minutes at 37 °C. Prolonged starvation does not appear to enhance active glucose uptake, and in unfasted guinea pigs an endogenous mean value of 2.15 mM glucose is present.A maximum capacity to accumulate glucose occurs at a point approximately 25 inches from the pyloric end of the jejunum.Study of the inhibition of glucose uptake by phlorhizin and phloretin indicates that these compounds inhibit the uptake of glucose competitively.
THE COMPETITIVE INHIBITION OF AMINE OXIDASE WITH SPECIAL REFERENCE TO THE CARCINOID SYNDROME
Authors: Fellman J. H. , Roth Esther S.
Published: December 2009

This report deals with an in vitro study of the competitive inhibition of monoamine oxidase by aromatic amines which are substrates for the enzyme. The metabolism of normetanephrine by mitochondrial monoamine oxidase was demonstrated to be competitively inhibited by 5-hydroxytryptamine, and in a similar fashion the oxidation of 5-hydroxytryptamine was shown to be inhibited by normetanephrine. An in vivo demonstration of this effect was contrived as a model of the carcinoid syndrome, and the pattern of the urinary metabolites was examined in rats before and after the intraperitoneal injection of 5-hydroxytryptamine. The data reveal a distortion in pattern of the urinary metabolites of the catecholamines consistent with the idea of an in vivo inhibition of monoamine oxidase by the appearance of a massive amount of 5-hydroxytryptamine. Evidence from a patient afflicted with carcinoid which suggests that this phenomenon operates in this clinical condition and that it may also account for the epinephrine triggering of the flushing syndrome is presented.
PLAQUE ASSAY OF SEMLIKI FOREST VIRUS IN ASCITES TUMOR CELLS
Authors: Faulkner P. , Harris R. G.
Published: December 2009

A plaque assay for Semliki Forest virus using ascites tumor cells in an agar cell-suspension technique is described.
SELECTIVE INHIBITION OF NICOTINAMIDE ADENINE DINUCLEOTIDE DEPENDENT OXIDATION BY 2-METHYL-3-o-TOLYL-4-QUINAZOLONE
Authors: Parmar Surendra S. , Seth P. K.
Published: December 2009

The effect of 2-methyl-3-o-tolyl-4-quinazolone (QZ-2) on the respiratory activity of rat brain homogenate and isolated mitochondria was investigated. QZ-2 selectively inhibited NAD-dependent oxidations of substrates of the tricarboxylic acid cycle, L-glutamate and β-hydroxybutyrate, while the oxidation of sodium succinate and NADH, independent of NAD, were unaffected. Increase in the concentration of QZ-2 increased the inhibition. Added NAD increased the respiratory activity of rat brain homogenate and isolated mitochondria during oxidation of sodium citrate, DL-isocitrate, α-ketoglutarate, L-malate, L-glutamate, and β-hydroxybutyrate. The inhibition produced by QZ-2 during such oxidation was reduced by the presence of added NAD. It seems that QZ-2 acts at a point before the entrance of electrons from succinic dehydrogenase and NADH to cytochrome b in the respiratory chain.
CARBOXYMETHYLATION OF THE METHIONINE RESIDUES OF CYTOCHROMEc
Authors: Tsai H. Jeng , Williams G. R.
Published: December 2009

Treatment of cytochrome c with iodoacetate at pH = 3.0 leads to loss of activity in the succinate oxidase system, alteration of spectra, and loss of the specific hemochrome properties characteristic of the native protein. The change in properties is paralleled by the incorporation of carboxymethyl groups (up to a maximum of two) and the destruction of methionine. The chymotryptic peptide maps also suggest that the loci of modification are the methionine residues at positions 65 and 80. Both residues are equally amenable to attack at about the same rate as free methionine, suggesting that they are located on the surface of the molecule. Certain features of the kinetics of carboxymethylation suggest the possible existence of a monocarboxymethyl derivative with unmodified properties, but modification of both methionines clearly leads to marked loss of function.
AN EXTRACELLULAR PROTEASE FROM ASPERGILLUS FUMIGATUS
Authors: Martin S. M. , Jönsson A. G.
Published: December 2009

An extracellular proteolytic enzyme produced by Aspergillus fumigatus has been isolated and purified. Preparations showed two distinct peaks of activity when allowed to act on proteins buffered at different pH's (pH 7 and 10 with casein and pH 4 and 9 with hemoglobin). Although this might suggest the presence of distinct neutral and alkaline proteases, all other observations (column chromatography, electrophoresis, heat inactivation, etc.) indicated that a single enzyme was involved. The enzyme hydrolyzed polyglutamic acid and polylysine optimally at about pH 4 and 10 respectively, with the rate of hydrolysis of pofyglutamic acid being about 10 times that of polylysine. The products of digestion of polyamino acids were the corresponding peptides, no trace of monomer being found.
CHANGES IN THE MAJOR MACROMOLECULAR FRACTIONS OF EGG YOLK DURING EMBRYOGENESIS
Authors: Saito Z. , Martin W. G. , Cook W. H.
Published: December 2009

Yolk from fertile eggs was separated into its three major fractions (granule, low-density, and water-soluble) after 0, 6, 12, 15, and 18 days' incubation. Qualitative and quantitative changes in whole yolk and its fractions were small during the first 12 days, but later marked changes occurred. A decrease in the proportions of granule and low-density fractions and an increase in the water-soluble fraction account for most of the overall changes in the nitrogen, phosphorus, and lipid contents of yolk. Qualitatively the lipid-rich low-density fractions showed little change. The granule fraction, however, lost phosphorus, and at least one new component was evident in both its ultracentrifugal and electrophoretic patterns. A marked increase in the amount of water-soluble material after 12 days' incubation can be attributed to the appearance of a new component having sedimentation and electrophoretic mobilities similar to those of ovalbumin.
FATTY ACIDS IN DROSOPHILA MELANOGASTER: II. SEPARATION AND IDENTIFICATION OF SATURATED FATTY ACIDS IN DROSOPHILA MELANOGASTER
Authors: Kato Mikio
Published: December 2009

The component saturated fatty acids of the lipids extracted from the pupal tissues of Drosophila melanogaster have been determined. Treating the mixture of acids with p-bromophenacyl bromide and 2,4-dinitrophenylhydrazine permitted the separation of the saturated from the unsaturated acids. The derivatives were separated by reversed-phase paper chromatography.The following saturated fatty acids were found in the pupal extracts: n-octadecanoic (stearic), n-hexadecanoic (palmitic), n-tetradecanoic (myristic), n-dodecanoic (lauric), n-decanoic (capric), n-octanoic (caprylic), n-hexanoic (caproic), and n-butanoic (butyric) acids.
LYTIC ENZYMES OF SORANGIUM SP.: A COMPARISON OF THE PROTEOLYTIC PROPERTIES OF THE α- AND β-LYTIC PROTEASES
Authors: Whitaker D. R. , Roy C. , Tsai C. S. , Jurášek L.
Published: December 2009

The proteolytic properties of the α- and β-lytic proteases of a species of Sorangium were compared. Neither enzyme showed evidence of aminopeptidase, carboxypeptidase, or amidase activity in tests with a series of peptides and substituted amino acids at pH 5.2, 7.2, and 9.0. Neither enzyme showed evidence of esterase activity towards N-benzoyl-L-arginine methyl ester at pH 6.8. Hydrolysis of the A chain of oxidized insulin at pH 9 slows down markedly when the α-enzyme has cleaved the chain once; the initial fast cleavage can take place at linkages between residues 9 and 10, 10 and 11, and 12 and 13; more slowly cleaved linkages are between residues 3 and 4, and 8 and 9. Hydrolysis of the B chain by the α-enzyme at pH 9 is still faster and slows down when the chain has been cleaved twice. One fast cleavage is at the linkage between residues 18 and 19; the other can take place at the linkages between residues 12 and 13, and 14 and 15; more slowly cleaved linkages are between residues 8 and 9, 9 and 10, and 15 and 16. Under the conditions tested, the β-enzyme does not hydrolyze the A chain appreciably at pH 9. It cleaves the B chain rapidly at the linkage between residues 23 and 24 and more slowly at linkages between residues 18 and 19. The linkages split by both enzymes are those which involve the carboxyl group of a neutral amino acid.
THE ROLE OF MAGNESIUM IN THE OXIDATION OF EXTERNAL REDUCED NICOTINAMIDE ADENINE DINUCLEOTIDE BY RAT LIVER MITOCHONDRIA
Authors: Cereijo-Santaló Roberto
Published: December 2009

The oxidation of added dihydro-nicotinamide-adenine dinucleotide (NADH) by rat liver mitochondria in the presence of different concentrations of magnesium was studied.It was found that, in the absence of added magnesium, NADH was oxidized rapidly by isolated rat liver mitochondria. The addition of either magnesium or ATP strongly inhibited the oxidation of NADH.The inhibition of NADH oxidation induced by magnesium was not released by the addition of a phosphate acceptor, but it was partially released by the addition of ATP at concentrations lower than that of magnesium. As the concentration of ATP increased over that of magnesium, its releasing effect tended to disappear.Similarly, the inhibition of NADH oxidation induced by ATP was partially released by the addition of magnesium at concentrations lower than that of ATP. As the magnesium concentration increased over that of ATP, its releasing effect diminished and eventually caused a greater inhibition than that produced by ATP alone.It is suggested that conditions similar to those described in the oxidation of added NADH by isolated rat liver mitochondria might also occur in the intact cell.
THE EFFECT OF FASTING ON ESTERIFICATION OF PALMITATE BY RAT LIVER IN VITRO
Authors: Rubenstein Bernard , Rubinstein David
Published: December 2009

The ability of liver slices from rats fasted 48 hours to esterify palmitate-1-14C is about half of that of slices from fed animals. The same effect can be observed in homogenates of liver freed of nuclei, either with or without mitochondria. In both preparations, the synthesis of triglycerides is chiefly affected. The decrease in esterification by homogenate supernatants containing microsomes from fasted animals can be overcome by using increased amounts of ATP or an ATP generator and NaF in the incubation medium. The ATPase responsible for the higher ATP requirement in liver homogenates from fasted animals is Mg++-dependent. Higher concentrations of ATP inhibit esterification by mitochondrial preparations. Incorporation of both palmitate-9-10-3H and of glycerol-1-3-14C is reduced to the same extent for each compound in slices from fasting animals. Glycerol kinase and α-glycerophosphate dehydrogenase are both unaffected by 48 hours' fasting. It is concluded that the decrease in ATP from the activation of ATPase is responsible for the decreased esterification in the intact cell.
FRAGMENTATION OF IMMUNOGLOBULIN DURING STORAGE
Authors: Connell G. E. , Painter R. H.
Published: December 2009

Solutions of human γ-globulin undergo changes on storage resulting in the formation of fragments similar to those produced by the digestion of human γ-globulin with the enzymes papain and plasmin. Two fragments have been isolated from the naturally fragmented material which resemble the Fab and Fc fragments resulting from digestion by papain. The fragments have been characterized on starch gel, by amino acid analysis, and in the ultracentrifuge, and appear to be identical with similar fragments isolated from plasmin digests of human γ-globulin. The natural Fc-like fragment differs from the papain Fc fragment but the Fab fragments from the three sources appear to be identical. Like the papain Fab fragment, the naturally occurring and plasmin-induced Fab fragments have antibody activity.
SYNTHESIS OF GLYCEROL-1,3-DIPHOSPHATE
Authors: Kates M. , Palameta B. , Chan T. H.
Published: December 2009

Glycerol-1,3-diphosphate was synthesized in an overall yield of 40% by the following sequence of reactions. 1,3-Dibromo-2-propanol was esterified with palmitoyl chloride in quinoline to give 1,3-dibromo-2-hexadecanoyloxypropane (I). Reaction of I with 2 moles of silver dibenzyl phosphate in boiling benzene gave tetrabenzyl 2-hexadecanoyl-1,3-glycerodiphosphate (II). The benzyl groups were removed from II by catalytic hydrogenolysis with palladium on charcoal, and the palmitoyl group was removed by mild alkaline hydrolysis. The resulting glycerol-1,3-diphosphate (IV) was isolated as the dibarium salt.
UNCOUPLING OF OXIDATIVE PHOSPHORYLATION BY VANADATE
Authors: Hathcock John N. , Hill C. H. , Tove S. B.
Published: December 2009

The addition of ammonium metavanadate to the diet of chicks at a level to supply 25 parts per million vanadium uncoupled oxidative phosphorylation in mitochondria isolated from the livers. In vitro studies revealed that 1 mM vanadate uncoupled oxidative phosphorylation in liver mitochondria. This uncoupling was manifest whether succinate or β-hydroxybutyrate was used as the substrate, suggesting that all three phosphorylating sites associated with electron transport were uncoupled.At a concentration of 0.1 mM, vanadate increased the destruction of adenosine triphosphate by mitochondria. As the concentration of vanadate was increased the destruction of adenosine triphosphate became progressively less. The exchange reactions of adenosine triphosphate with orthophosphate and with adenosine diphosphate, catalyzed by liver mitochondria, were inhibited by 0.1 mM vanadate. These results suggest the possibility that the known toxic effects of vanadium in vivo are related to the uncoupling of oxidative phosphorylation.
IMPROVED TECHNIQUE FOR SEPARATION AND IDENTIFICATION OF BOVINE BETA GLOBULINS BY STARCH-GEL ELECTROPHORESIS
Authors: Makarechian M. , Howell W. E.
Published: December 2009

By the use of a buffer solution of pH 7.3–7.35 for the preparation of the gel for starch-gel electrophoresis, it was shown that each transferrin allele produces six distinct protein bands. When the sera were treated with59Fe, it was confirmed by radioautography that all the protein bands were transferrins. It was demonstrated that this modification also facilitates the differentiation between transferrin types whose bands migrate very close to each other in starch-gel electrophoresis.
PURIFICATION AND PROPERTIES OF AN INDUCIBLE β-GLUCOSIDASE OF BAKERS' YEAST
Authors: Inamdar A. N. , Kaplan J. G.
Published: December 2009

The inducible β-glucosidase present in crude extracts of cellobiose-grown bakers' yeast (Saccharomyces cerevisiae C) was purified 50-fold and found to be homogeneous in the ultracentrifuge, with a molecular weight of 313,000. The enzyme was virtually identical in its properties with the internal, cryptic enzyme of the yeast cell, revealed by butanol treatment of the suspensions. It was unlike the membrane-localized enzyme found at the surface of intact cells in its low affinity for cellobiose and methyl-β-glucoside as substrates and inhibitors. The enzyme was specific for the β configuration and had no activity against substrates such as α-glucosides, β-galactosides, or β-xylosides. It was highly active against both naturally occurring and synthetic substrates with aromatic aglycones, and may thus be classed as an aryl-β-glucosidase. The enzyme had weak hydrolytic activity against methyl-β-glucoside and cellobiose, but these compounds, unlike all of the aryl-β-glucosides tested, were not competitive inhibitors of its activity against the chromogenic substrate pNPG. There were about 40,000 molecules of enzyme per cell in fully induced cultures and the enzyme represented about 3% of the total protein of these cells.
POTASSIUM STIMULATION OF OXIDATION AND PHOSPHORYLATION IN PIGEON-MUSCLE MITOCHONDRIA
Authors: Marcus G. J. , Manery J. F.
Published: December 2009

With alpha-ketoglutarate as substrate and a hexokinase – glucose phosphate acceptor system, the rates of oxidation and phosphorylation of pigeon-muscle mitochondria were measured in media in which the proportion of potassium to sodium was varied. As the potassium concentration was elevated from 0 to about 70 mmoles/liter, the sodium concentration was correspondingly decreased. With both the Warburg apparatus and the polarograph, the rate of respiration was shown to rise as the proportion of potassium in the medium was increased. The mean rate in the high-potassium media was 130% of that in the high-sodium media over the five-minute period measured with the oxygen electrode, and 135% over the thirty-minute period measured by Warburg manometry. The rate of phosphorylation was stimulated to an even greater extent than the rate of oxidation as sodium was replaced by potassium. In every preparation tested, the rates of phosphorylation and the P/O ratios were higher in the high-potassium media than in the high-sodium media.
METABOLISM OF EHRLICH ASCITES TUMOR IN VITRO: SUBCELLULAR DISTRIBUTION OF PHOSPHOLIPIDS NEWLY FORMED FROM14C-LABELED PRECURSORS
Authors: Donisch V. , Rossiter R. J.
Published: December 2009

When Ehrlich ascites cells were incubated in a suitable medium containing choline-1,2-14C, ethanolamine-1,2-14C, L-serine-14C, or glycerol-1-14C, radioactivity was recovered from the lipid fraction. With choline-1,2-14C, radioactivity was incorporated into the three choline-containing phospholipids, lecithin, choline plasmalogen, and sphingomyelin. Radioactivity from ethanolamine-1,2-14C was incorporated into phosphatidyl ethanolamine, ethanolamine plasmalogen, choline plasmalogen, and lecithin. Radioactivity from L-serine-14C was incorporated into phosphatidyl serine, serine plasmalogen, and phosphatide acid, with lesser amounts into phosphatidyl ethanolamine, lecithin, ethanolamine plasmalogen, choline plasmalogen, and sphingomyelin. Radioactivity from glycerol-1-14C was incorporated into the glycerophosphatides, phosphatidic acid, lecithin, phosphatidyl ethanolamine, phosphatidyl serine, phosphatidyl inositol, and choline plasmalogen. Radioactivity from this precursor was also incorporated into sphingomyelin.In all instances, radioactivity was recovered from the phosphatides in the nuclear, mitochondrial, and microsomal fractions of the tumor. Usually, the specific radioactivity of the phosphatides in the microsomal fraction exceeded that in the other two subcellular fractions.
FATTY ACID SYNTHESIS AND CONTROL IN BROWN ADIPOSE TISSUE HOMOGENATES
Authors: Steiner George , Cahill Jr. George F.
Published: December 2009

Fatty acid synthesis was examined in brown adipose tissue homogenates. It was found to be an extramitochondrial, extramicrosomal process in contrast to fatty acid oxidation, which was mitochondrial, and to require ATP, coenzyme A, Mg++, citrate, and NADP. For the generation of NADPH2, glucose-6-phosphate and glucose-6-phosphate dehydrogenase were used. Exogenously added fatty acids inhibited fatty acid synthesis from acetate. Their potency as inhibitors was related to concentration, chain length, and unsaturation. The major site of inhibition appeared to be the acetyl-CoA synthetase reaction, but a second site of minor significance might exist subsequent to acetyl-CoA.
THE EFFECT OF THYROXINE ON THE UPTAKE AND METABOLISM OF3H-dl-ADRENALINE BY THE SMALL INTESTINE OF RAT IN VITRO
Authors: Keswani G. , D'Iorio A.
Published: December 2009

The uptake, binding, and metabolism of3H-dl-adrenaline by small-intestine strips has been studied in vitro for several concentrations of adrenaline and (or) thyroxine in the medium.The uptake of adrenaline was always larger in thyroxine-depleted tissues. It was dependent upon the external level of adrenaline and increased as a function of adrenaline concentration in the medium.The formation of metanephrine was independent of the thyroid state of the animal, but was dependent upon the external concentration of adrenaline.A dual role of thyroxine was observed in its effect on the binding of the biogenic amine by the small intestine. Intracellular thyroxine competes with adrenaline for common binding sites. It also appears from the data reported here that binding sites for adrenaline are present at the membrane of the cell. The intracellular binding sites for adrenaline appear to be saturated very rapidly. In the small intestine, binding is independent of the external level of adrenaline, but does depend upon thyroxine.
THE INCORPORATION OF α-GLYCEROPHOSPHATE-32P INTO THE LIPIDS OF RAT BRAIN PREPARATIONS: I. GENERAL PROPERTIES
Authors: Possmayer F. , Strickland K. P.
Published: December 2009

Studies have been carried out on the incorporation of32P-labeled α-glycerophosphate (α-G32P) into the lipids of preparations obtained from rat brain cerebral hemispheres. The optimal incorporating system contains Tris and phosphate buffers (pH 7.4), MgCl2, CoA, EDTA, NaF and ATP. The incorporation of α-G32P into monophosphoinositide was stimulated by CDP-choline, CDP-ethanolamine, CDP-glycerol and CTP. These nucleotides depressed the incorporation of α-G32P into phosphatidic acid. Microsomal preparations supported a high incorporation of α-G32P into phosphatidic acid, but the incorporation into monophosphoinositide was low compared with the whole homogenate. Similar observations were made with mitochondrial preparations undergoing oxidative phosphorylation with CoA added to the medium.
HORMONAL ACTION ON MONOAMINE OXIDASE ACTIVITY IN RATS
Authors: Ho-Van-Hap A. , Babineau L. M. , Berlinguet L.
Published: December 2009

Male young and adult rats were injected with thyroxin, hydrocortisone and puromycin. Monoamine oxidase (MAO) activity was studied in liver, brain, kidney, and heart with L-tryptamine-2-14C as substrate. After thyroxin treatment, heart MAO increased in young animals but decreased in adult animals. Thyroxin decreased liver MAO in adult animals. Brain MAO remained constant in all experiments, whereas kidney MAO showed a slight decrease after thyroxin injection. In young rats, puromycin did not prevent the increase in heart MAO caused by thyroxin injection. Hydrocortisone did not enhance MAO activity in liver, brain and heart. Of all organs studied, only the heart showed a marked increase of MAO with age. In female rats, thyroxin has little effect on brain and liver MAO, whereas it increases MAO activity in the heart of young and adult animals by 67% and 32% respectively. Adult female rats have twice as much heart MAO as males.
EFFECT OF VARIOUS PLANT PHENOLS ON PROTEIN SYNTHESIS IN EXCISED PLANT TISSUES
Authors: Parups E. V.
Published: December 2009

The flavonoids hesperitin, hesperidin, naringenin, naringin, quercetin, quercitrin, phloretin, phlorizin, and coumarin inhibited the incorporation of leucine-1-14C into the alcohol-insoluble material of potato-tuber slices and cell-free preparations of Escherichia coli. Flavonoids did not appear to affect substantially the uptake of leucine by potato-tuber tissues. The glycosides, as a rule, were less active inhibitors of uptake and incorporation of leucine than the corresponding aglycones. The tissue specificity towards the uptake and incorporation of leucine and the differences and possible structural changes of flavonoids are discussed.
CHROMATOGRAPHIC IDENTIFICATION OF ESTRIOL AND 16,17-EPIESTRIOL AS CONSTITUENTS OF THE URINE OF THE LAYING HEN
Authors: Mathur R. S. , Common R. H.
Published: December 2009

Presumptive estriol and 16,17-epiestriol fractions were separated from laying hens' urine by subjecting the hydrophilic fraction of the urinary phenolic extract to successive thin-layer chromatography (t.l.c), alumina-column chromatography, further t.l.c, and finally, microsublimation. The presence of estriol in the presumptive estriol fraction was confirmed by comparison of the thin-layer chromatographic behaviors of the phenol and four derivatives thereof with the behaviors of reference estriol and four corresponding derivatives of this reference material each in three different solvent systems. The presence of 16,17-epiestriol in the presumptive 16,17-epiestriol fraction was confirmed by similar comparisons of the presumptive 16,17-epiestriol fraction and five derivatives thereof with reference 16,17-epiestriol and five corresponding derivatives each in three solvent systems; and chromatographic correspondences for two further derivatives were observed in one solvent system each.It is concluded that estriol and 16,17-epiestriol are normal constituents of hens' urine.
FACTORS AFFECTING THE INCORPORATION OF PRECURSORS INTO THE PHOSPHOLIPIDS OF EHRLICH ASCITES CELLS
Authors: Johnstone R. M.
Published: December 2009

The incorporation of choline-methyl-14C, ethanolamine-1,2-14C, and32Piinto the phospholipids of Ehrlich ascites cells is enhanced under aerobic conditions by the presence of glucose. The extent of incorporation of each of the three precursors is the same under aerobic or anaerobic conditions if glucose is present. The formation of free phosphocholine and free phosphoethanolamine exceeds by a factor of 10 the incorporation of choline-methyl-14C and ethanolamine-1,2-14C into the phospholipids. The data suggest that acid-soluble phosphocholine and phospho-ethanolamine are not in rapid isotopic equilibrium with the phosphorylated bases present at the sites of phospholipid synthesis.
THE MECHANISM AND SPECIFICITY OF GUANINE DEAMINASE
Authors: Roy Joan E. , Roy Kenneth L.
Published: December 2009

Guanine deaminase from lingcod muscle has been found to remove chlorine from 2-chloro-6-hydroxypurine, hydrazine from 2-hydrazino-6-hydroxypurine, and methylamine from 2-methylamino-6-hydroxypurine, with xanthine as the product in all cases. Methylation of guanine on nitrogen atoms other than N-1 and substitutions at C-6 eliminate susceptibility to guanine deaminase. Kinetic data for the reaction of guanine deaminase with five substrates are presented and the results of a survey of possible inhibitors of the enzyme are given. The results tend to support a requirement by guanine deaminase for the lactam tautomeric form of the substrate.
EFFECTS OF INTRAVENOUS ADMINISTRATION OF ADRENOCORTICOTROPHIN ON THE ADRENAL LIPIDS OF THE RABBIT
Authors: Moore J. H. , Noble R. C. , O'Donoghue P. N.
Published: December 2009

Groups of male rabbits were killed 10, 20, 30, 60, 120, or 240 min after an intravenous injection of ACTH (4 I.U./kg). Control rabbits were killed before or immediately after adrenocorticotrophin (ACTH) administration. There was a pronounced decrease in the proportion of cholesteryl esters and an increase in the proportion of unesterified fatty acids in the adrenal lipids during the first 30 min after the injection of ACTH. This decrease in the proportion of esterified cholesterol was accompanied by increases in the concentrations of adrenic and docosahexaenoic acids and decreases in the concentrations of linoleic, linolenic and homo-γ-linolenic acids in the cholesteryl esters. From 30 to 240 min after ACTH administration, the concentrations of these polyunsaturated fatty acids in the cholesteryl esters partially reverted to the values in the control rabbits. The fatty acid acid compostions of the adrenal triglycerides, unesterified fatty acids, and phospholipids were unaltered by the administration of ACTH.
THE EFFECT OF STRUCTURE ON NUCLEOSIDE KINASE ACTIVITY
Authors: Pierre K. J. , Kimball A. P. , LePage G. A.
Published: December 2009

A study was made of the in vitro phosphorylation of some nucleosides in cell-free extracts from a thioguanine-resistant subline of Ehrlich ascites carcinoma which lacked inosine monophosphate – guanosine monophosphate pyrophosphorylase. The results indicated that there were kinases which catalyzed the phosphorylation of a variety of nucleosides. Ribofuranosyl-6-thiopurme was phosphorylated whereas the xylofuranosyl-, arabinofuranosyl-, and lyxofuranosyl-6-thiopurine were not substrates. The xylose and ribose derivatives of 6-methylthiopurine were phosphorylated but the arabinose derivative was not. Guanosine and some of its analogs were also phosphorylated but no correlation could be found between structure and phosphorylation of the guanosine analogs tested.The reaction showed dependence on the addition of divalent cation and an ATP-regenerating system.
LIPIDS OF SUBCELLULAR PARTICLES FROM BOVINE HEART MUSCLE: I. FATTY ACIDS OF NEUTRAL LIPIDS
Authors: Nazir Darius J. , Alcaraz Aurora P. , Nair Padmanabhan P.
Published: December 2009

The fatty acid composition of various lipid classes obtained from subcellular fractions of bovine heart muscle by column chromatography on silicic acid has been examined by gas-liquid chromatography on diethyleneglycol succinate and Apiezon L columns. The nuclear and cytoplasmic fractions together constituted the major lipid compartments of the myocardial cell, the cytoplasmic subcellular organelles accounting for only about 4% of the total lipid. Among the total fatty acids of each subcellular fraction, there was a remarkable constancy in the relative amounts of monoethenoid fatty acids (about 23%). More than 90% of the total fatty acids had chain lengths between C18and C20. Approximately 3–4% of longer chain length fatty acids were present in the mitochondrial and cytoplasmic fractions. There was a predominance of monoenes (36%) and long chain fatty acids (> C20) in the cholesteryl esters associated with the "microsomal" preparation. Although the monoethenoid fatty acids of triglycerides were subject to considerable variation, the nuclear and cytoplasmic compartments consistently showed about 40% of this class of fatty acid. In sharp contrast to all other neutral lipid classes, polyethenoid fatty acids constituted a significant proportion of the total free fatty acids in all subcellular organelles. The heavy mitochondrial and cytoplasmic fractions showed relatively higher concentrations of polyethenoid free fatty acids. In view of the fact that free fatty acids constituted the main source of energy from fats for the myocardium, the hypothesis has been advanced that heart muscle mitochondria preferentially extract the readily oxidizable free polyunsaturated fatty acids from the cytoplasmic environment to fulfill the energy demands of the aerobic cell.
FRUCTOSE DIPHOSPHATE ALDOLASE FROM FUSARIUM OXYSPORUM f. LYCOPERSICI: III. STUDIES ON THE MECHANISM OF REACTION
Authors: Ingram J. M.
Published: December 2009

Frnctose-1,6-diphosphate aldolase from Fusarium oxysporum f. lycopersici is inhibited by acetylimidazole. The inhibition is reduced in the presence of fructose diphosphate or DL-glyceraldehyde-3-phosphate, but not in the presence of dihydroxyacetone phosphate. Under conditions of almost total inactivation, as measured by the rate of cleavage of fructose diphosphate, the decrease in the rate of exchange is only 18%. These results indicate that the amino acid residues which are altered under these conditions are concerned with the D-glyceraldehyde-3-phosphate rather than the dihydroxyacetone phosphate active site.The rate of cleavage of fructose diphosphate in D2O decreases, with increasing pH, more rapidly than the rate in H2O and resembles the decreased rate of tritium exchange into dihydroxyacetone phosphate with increasing pH. These results suggest that a correlation exists between the isolated proton exchange and cleavage reactions and that the decreased rate of exchange and cleavage with increasing pH is due to a decreased rate of proton neutralization of the enzyme – dihydroxyacetone phosphate anion. The addition of acetaldehyde to the aldolase assays at pH 8.0 and pH 9.0 stimulates the cleavage rate of fructose diphosphate to a level normally obtained at pH 7.5, confirming the supposition that the release of dihydroxyacetone phosphate becomes rate limiting with increasing pH. The results obtained by following the cleavage in D2O also indicate that general base catalysis is involved in the proton neutralization step and that the pK of the general base is less than pH 6.0. The evidence suggests that the general base is either a β-COOH of aspartate or a γ-COOH of glutamate.
The chain termini of polynucleotides formed by limited enzymic fragmentation of wheat embryo ribosomal RNA. Part 2. Studies of a snake venom ribonuclease and pancreas ribonuclease
Authors: McLennan B. D. , Lane B. G.
Published: December 2009

A snake venom ribonuclease, similar to the classical pancreas ribonuclease, can be freed of other known nucleolytic activities by acid treatment, or by acetone-fractionation of Russell viper venom. Utilizing an end-group analytical technique in conjunction with oligonucleotide analyses of both partial and complete digests of ribonucleates, it has been possible to broadly characterize the mode of action of the snake venom ribonuclease, even though it is present in such small amount in venom that extensive purification was not attempted. The venom ribonuclease parallels pancreas ribonuclease in its acid stability, pH dependence, and high degree of preferential specificity toward PypA bonds in ribonucleate chains. Studies of the limited fragmentation of ribosomal and soluble ribonucleates, as well as dinucleoside phosphates, have shown that there are subtle differences between the venom and pancreas ribonucleases. The results of the investigation suggest that the venom and pancreas ribonucleases can be useful as a means of introducing a limited number of preferential scissions into ribonucleate chains at PypA internucleoside phosphodiester bonds. Incidental to the principal investigations dealing with the mode of action of the venom and pancreas ribonucleases on ribonucleates, certain features pertaining to the nucleotide sequences in ribosomal and soluble ribonucleates from wheat embryo have been noted.
Effect of benzimidazole and kinetin on the nicotinamide nucleotide content of senescing wheat leaves
Authors: Mishra D. , Waygood E. R.
Published: December 2009

Assays of nicotinamide nucleotides were made on detached leaves of wheat, Triticum dicoccum var. Khapli, immediately after excision and at the end of a 16-h photoperiod and 8-h dark period at 1, 3, and 5 days on leaves floated on water, and on benzimidazole, kinetin, or both. The total nicotinamide nucleotide content of 25 nmoles per gram fresh weight was increased by treatments with these kinins. A diurnal rhythm was observed in all treatments involving an increase of NADP(H) and a decrease of NAD(H) during the photoperiod, whereas the opposite was the case in darkness. The ratio NAD(H)/NADP(H) was about equimolar after excision and decreased to a mean value of 0.4 in all treatments after the first photoperiod. Thereafter, despite fluctuations in light and darkness and increased synthesis of NADPH in the treatments, the ratio increased to a mean value of 1.5 after 5 days, with no significant difference between treatments. The transformations in light can be explained by the combined operation of NAD kinase, NADH transhydrogenase, photosynthetic electron transfer forming NADPH, and biosynthetic reductive reactions restoring NADP.Assays were also made on chloroplasts isolated in nonaqueous media from leaves treated similarly but under continuous illumination. The NAD content of chloroplasts was 11.2 nmoles per μmole chlorophyll as compared to 3.14 for NADP. The oxidized nucleotides predominated in chloroplasts. Chloroplasts from leaves floated on water had lost all their NADP after 6 days, whereas those treated with benzimidazole or kinetin increased or maintained their level of NADP. The evidence is discussed with reference to the mechanism of action of benzimidazole and kinetin in delaying the onset of visible and metabolic changes that occur during the senescence of wheat leaves.
Aortic glycosaminoglycans in atheroma and alloxan diabetes
Authors: Ichida Tokuro , Kalant Norman
Published: December 2009

(1) Rabbits and rats were fed a high-fat, high-cholesterol diet to produce lipid deposition in the wall of the aorta. The intima and inner media were examined for their content of lipids, protein-bound carbohydrates, and individual glycosaminoglycans. In addition, the rate of uptake of 35S from sulfate into the sulfated glycosaminoglycans was measured in some animals.(2) In the rat, lipid accumulation was minimal; there were increases in the protein-bound hexosamine and sialic acid and decreases in all the glycosaminoglycans (hyaluronic acid, heparan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and dermatan sulfate).(3) In the rabbit, lipid accumulation was marked in the normal appearing tissue and still greater in the "fatty streaks". There were associated increases in protein-bound hexosamine and hexose and, in the fatty streaks, of sialic acid also. The concentrations of all sulfated glycosaminoglycans were higher in the fatty streaks than in the surrounding tissue.(4) In the rat, the rate of synthesis of chondroitin sulfates, as reflected in sulfate-35S incorporation, was not increased, but the turnover of chondroitin sulfates as reflected in the fractional rate of 35S incorporation was increased; this is taken as evidence that the fall in concentration was due to an increase in the rate of removal. In the rabbit, both synthesis and turnover of chondroitin sulfates were greatly increased in the fatty streaks; the change in synthesis was greater and led to the increase in the concentrations of these substances.(5) The concentration of hyaluronic acid was increased in the aortae of alloxan diabetic animals. Sulfate incorporation was reduced, indicating decreased synthesis of sulfated glycosaminoglycans. Despite this, the aortae of diabetic animals had virtually the same composition (except for hyaluronic acid) as those of non-diabetics given the same diet.