bluuebunny/crossref_metadata_2025 huggingface dataset:
THE METABOLISM OF NITROGEN AND THE DIGESTIBILITY COEFFICIENT AND BIOLOGICAL VALUE OF THE PROTEINS AND NET PROTEIN UTILIZATION IN POOR RICE DIET SUPPLEMENTED WITH METHIONINE-FORTIFIED SOYA FLOUR OR SKIM MILK POWDER
Authors: Panemangalore Myna , Parthasarathy H. N. , Joseph Kantha , Sankaran A. N. , Rao M. Narayana , Swaminathan M.
Published: December 2009

The effect of supplementing a poor rice diet commonly used in India with methionine-fortified soya flour or skim milk powder was studied in seven girls aged 8–9 years, using as criteria: the retention of nitrogen, digestibility coefficient, biological value, and net protein utilization of the proteins. The retention of nitrogen on the rice diet was very low (20.3 mg/kg day). Supplementation of the rice diet with soya flour, methionine-fortified soya flour or skim milk powder, so as to provide about 1 g/kg extra protein, made up the protein deficiency in the rice diet and resulted in a significant increase in nitrogen retention (95.6, 112.1, and 113.6 mg/kg day). The retention of nitrogen on the rice diet supplemented with methionine-fortified soya flour (112.1 mg/kg day) or skim milk powder (113.6 mg/kg day) was nearly the same and significantly higher than that (95.6 mg/kg day) observed with a diet supplemented with soya flour. The biological value and net protein utilization of the mixed proteins of rice – skim milk powder diet and rice–methionine-fortified soya flour diet (62.4 and 62.2 and 53.3 and 54.0 respectively) were nearly the same and significantly higher than those (58.3 and 49.9) of rice – soya flour diet. The results show that methionine-fortified soya flour is almost as good as skim milk powder and significantly superior to soya flour as a protein supplement to rice diet.
THE CHEMICAL MODIFICATION OF CHYMOTRYPSIN
Authors: Dixon G. H. , Schachter H.
Published: December 2009

Chemical modification of chymotrypsin has led to the identification of several amino acid side-chains which are probably constituents of the active site of the enzyme. A single seryl and a single histidyl residue appear to cooperate in catalyzing the bond-breaking process while one or more tryptophanyl residues may be involved in the specific binding of substrate. Neither of the two methionyl residues is essential for enzyme activity although changes in kinetic properties occur when they are modified by oxidation or alkylation.
THE RELATION BETWEEN STRUCTURE AND FUNCTION IN HEMOGLOBINS
Authors: Riggs Austen
Published: December 2009

Many lines of evidence indicate that the oxygenation of hemoglobin is accompanied by changes in protein structure. Data on the oxygen equilibria of the hemoglobins from a number of animals are discussed in terms of this evidence. Evidence from studies of some hemoglobins (lamprey, frog and tadpole) indicates a major role for subunit dissociation equilibria in explaining two properties of the oxygen equilibria: heme–heme interaction and the "Bohr effect". The importance of subunit dissociation in mammalian hemoglobins is suggested by the known concentration dependence of the oxygen equilibria. Mammalian hemoglobins are composed of two types of polypeptide chains, α and β. The idea that the α and β subunits have different oxygen equilibria and are affected differently by pH is examined. It is concluded that the β-chains appear to play a major role in the mechanism of the Bohr effect not shared by the α-chains. This conclusion is supported by the structural changes in hemoglobin found to occur upon oxygenation by X-ray diffraction techniques.
INFLUENCES OF THYROXINE AND INSULIN ON THE TURNOVER AND FATE OF HIGH-ENERGY PHOSPHATE
Authors: Dow Dorothy S.
Published: December 2009

Ingestion by the weanling rat of thyroxine in an amount greatly in excess of physiological requirements resulted in significant increases in the rates of turnover of the high-energy compounds phosphocreatine (PC), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) and in significant decreases in their concentrations in skeletal muscle. Nucleoside phosphorylase and myokinase activities and rates of pyrophosphate splitting of ATP and of utilization of ATP for nuclear syntheses were unaltered in thyrotoxic muscle. The findings suggest that increased extramitochondrial utilization of ATP for glycolysis may be the factor responsible for the increased phosphorylating capacity of the thyrotoxic animal. An effect of thyroxine on mitochondrial permeability as well as on rate of formation of the high-energy intermediate would appear to explain the observed results.A further enhancement of the already markedly elevated thyrotoxic rate of phosphorylation was effected by the superimposition of insulin. Insulin also effected increases in the concentrations of the high-energy compounds. It is apparent that insulin acts by reducing the utilization of ATP for phosphorylation of glucose and thus increases the mitochondrial availability of high-energy acceptor. This increased mitochondrial affinity for high-energy compounds results in an enhancement of mitochondrial energy transfer processes.The findings appear to involve both thyroxine and insulin in the control of cell structure.
PARATHION AND METABOLISM OF VITAMIN A IN THE RAT
Authors: Phillips W. E. J.
Published: December 2009

The liver storage of vitamin A has been studied in the rat following the feeding of 10 p.p.m. parathion in the diet for periods up to 70 days. No detrimental effect of parathion was observed on the degree of liver storage of vitamin A. Similarly, parathion did not adversely affect the rate of decrease of hepatic vitamin A stores.
THE METABOLISM OF ANTIGENS IN VIVO: I. PROTEIN ANTIGENS
Authors: Richter M. , Larose C. , Rose B.
Published: December 2009

Attempts were made to detect antigenic fragments in the sera or spleens of rabbits given a single intravenous injection of bovine serum albumin, human gamma-globulin, or human serum albumin. The results obtained, using a number of different methods for the detection of antibody–antigen interaction (double diffusion in gel, immunoelectrophoresis, inhibition of hemagglutination), failed to provide any evidence in favor of the presence of antigenic fragments either in the circulation or in the spleen of the experimental animal.
PURIFICATION OF FOLLICLE-STIMULATING HORMONE FROM HUMAN ANTERIOR PITUITARY GLANDS
Authors: McShan W. H. , Saxena B. B. , Creek R. O.
Published: December 2009

The results of this study indicate that highly purified follicle-stimulating hormone (FSH) was prepared from human anterior pituitary glands by ammonium sulphate (AS) fractionation, zone electrophoresis, and starch gel electrophoresis. The activity of this preparation was approximately 14.7 times that of the sheep pituitary FSH standard. The fractions from zone and starch gel electrophoresis with which luteinizing hormone (LH) was associated also contained thyrotropic hormone (TSH). There was little decrease in the gonadotropic activity of human anterior pituitary glands recovered at different times up to 24 hours post-mortem.
THE GERMINATION OF SEEDS OF MELILOTUS ALBA
Authors: Stoker J. R.
Published: December 2009

The contents of coumarin and coumarinic acid β-glucoside in germinating seeds of Melilotus alba, Arctic variety, have been measured. Non-germinating seeds were found to possess a large amount of free coumarin while in rapidly germinating seeds coumarinic acid β-glucoside was more prevalent. Coumarin and coumarinic acid β-glucoside have been examined as inhibitors of germination of M. alba seeds, the latter compound being much less efficient in this respect. Neither compound caused permanent inhibition of germination but only delayed the visible recognition of germination, this being because of the ability of the seeds to metabolize coumarin.
THE BIOSYNTHESIS OF AMINO ACID ACCEPTOR RNA
Authors: Cook R. A. , Bouchard J. P. , Fraser M. J.
Published: December 2009

Preliminary observations have been made on the biosynthesis of amino acid acceptor RNA in the mouse Ehrlich ascites carcinoma. Measurements have been made of the incorporation of radioactivity from either14C-CH3-methionine or uridine-2-14C into the RNA of nuclear and cytoplasmic fractions which precipitate at pH 5.0 from 105,000 × g supernatants of broken nuclei preparations and of cell homogenates ("soluble" RNA or sRNA). With either labelled precursor higher specific activities were found in the nuclear than in the cytoplasmic sRNA fractions. Whereas actinomycin D and DNase inhibited the incorporation of radioactivity from uridine-2-14C into nuclear sRNA, these agents stimulated significantly the incorporation of radioactivity from14C-CH3-methionine. The glycine acceptor capacity of nuclear sRNA was found to be greater than that of cytoplasmic sRNA. The base ratios of the amino acid acceptor RNA fractions derived from nuclear sRNA and from cytoplasmic sRNA by chromatography on methylated albumin columns were very similar. The results are consistent with the hypothesis that the amino acid acceptor RNA is made on a DNA-template in the nucleus of the tumor cells, is subsequently released from the template, methylated, and then transferred to the cytoplasm.
THE ROLE OF ADENOSINE TRIPHOSPHATE IN TRANSPORT REACTIONS
Authors: Scholefield P. G.
Published: December 2009

The evidence bearing on the participation of adenosine triphosphate (ATP) in transport reactions is reviewed. The connection may take the form of a strict quantitative relationship as observed in potassium uptake by red blood cells or as in amino acid uptake by slices of rat brain cortex. There may also be a qualitative relationship such as that observed in studies of amino acid uptake by Ehrlich ascites carcinoma cells. In other tissues (e.g. slices of the Ehrlich carcinoma) amino acid uptake may only have an uncertain relationship to the ATP content of the tissue. Some of the schemes which have been put forward to account for the involvement of ATP are discussed.
EVIDENCE FOR THE EXISTENCE OF TRANSPORT CARRIERS BASED ON INHIBITION STUDIES
Authors: Johnstone Rose M.
Published: December 2009

The transport of sugars or amino acids in various mammalian and bacterial preparations is inhibited by a limited number of structural analogues of the substrate under investigation. Factors which affect the transport of one class of substrates may have little effect on another class of substrates, indicating that highly specific systems are involved in transport.
WATER TRANSPORT AT CELL MEMBRANES
Authors: Pappius Hanna M.
Published: December 2009

Using cerebral cortex slices in vitro as an example, it is shown that there is no need to postulate active transport of water in the control of cellular volume of most tissues.In the elaboration of secretions of different osmolarity from that of plasma, active transport of water is also no longer invoked. The current theory of formation of hypertonic urine postulates that all the water movements involved remain passive and secondary to active solute transport. Water uptake from the gastrointestinal tract against a concentration gradient is explained in terms of hydrostatic pressure gradients generated within the tissue itself by active solute transport.Water movements involved in changes of mitochondrial volume are explained as a passive consequence of changes in the mitochondrial membrane.It is concluded that in all cases changes in the distribution of water are brought about by passive processes, often in consequence of active transport of ions and metabolites, and that such movement of water does not constitute active transport of water.
THE ALKALI-STABLE DINUCLEOTIDE SEQUENCES IN 18 S + 28 S RIBONUCLEATES FROM WHEAT GERM
Authors: Singh H. , Lane B. G.
Published: December 2009

The 2′-O-methyl substitution of ribose residues of ribonucleate chains can give rise to 16 alkali-stable dinucleotides having the general structure NxpNp in which N is any of the four major ribonucleosides and Nx is the 2′-O-methyl derivative of any of the four major ribonucleosides. Quantitative data are presented which show that all of these 16 alkali-stable dinucleotides occur in characteristic amounts in alkali hydrolyzates of the 18 S + 28 S ribonucleates from wheat germ. The alkali-stable dinucleotides cumulatively account for 3 mole% of the total nucleotides of the 18 S + 28 S wheat germ ribonucleates. The relative amounts of the four 2′-O-methyl ribosides responsible for the alkali stability of the dinucleotides have been shown to be distinctly different from the relative amounts of the four corresponding normal ribosides which participate in either the alkali-stable dinucleotide sequences or in the ribonucleate chains as a whole. Quantitative end group data show that the alkali-stable dinucleotide sequences occur internally in high molecular weight ribonucleate chains. Preliminary data are presented on the occurrence of alkali-stable trinucleotides in alkali hydrolyzates of the 18 S + 28 S wheat germ ribonucleates.
STUDIES ON BRAIN GANGLIOSIDES: I. THE ISOLATION AND COMPOSITION OF A TRISIALOGANGLIOSIDE
Authors: Wolfe L. S. , Lowden J. A.
Published: December 2009

Brain gangliosides, extracted with tetrahydrofuran and then purified, contained 1.03 ± 0.05 μmoles N-acetylneuraminic acid (NANA) per mg. They separated into five major and four minor components on thin-layer chromatograms.Gangliosides extracted from acetone powders of brain with hot chloroform–methanol separated on cellulose columns into two crude fractions (I and II). Purified, fraction II was a trisialoganglioside containing 1.29 μmoles NANA/mg. It was the slowest-moving component on thin-layer chromatograms. Fraction I was a mixture of mono- and di-sialogangliosides and contained the other chromatographic components. The molar ratio of hexose:ceramide of all preparations was close to 3:1. The molar ratio of galactose:glucose also was close to 3:1.The chromatography of gangliosides on cellulose columns varies significantly with different kinds of cellulose. Fraction I gangliosides appeared as one peak with Schleicher and Schuell pulp but ran as two separate peaks on Whatman cellulose. A modified method is described for the assay of sphingosine in gangliosides.
THE COMPOSITIONS OF SOME PEPTIDES PRODUCED BY AN ENZYMIC HYDROLYSIS OF WHEAT GLIADIN
Authors: Finlayson A. J.
Published: December 2009

Wheat gliadin was hydrolyzed extensively by treatment with pepsin and then by trypsin. A large number of peptides were produced as well as small amounts of some amino acids, thus indicating a substantial amount of hydrolysis of gliadin by the enzymes. Five peptides were obtained crystalline and two of these constitute 11.5% and 1.2% of gliadin, respectively. Their structures have been partly determined. The results indicate that wheat gliadin contains (Asp.Asp) bonds and at least 1.9% of the glutamic acid is present as glutamylglutamic acid.
BACTERIAL LIPIDS AND THE GRAM STAINING REACTION
Authors: Bergh A. K. , Webb S. J. , McArthur C. S.
Published: December 2009

In this study, no correlation was found between the Gram staining reaction of bacterial cells and the kinds of fatty acids in the lipids. The polar solvent (usually alcohol) used to wash out the stain from Gram-negative organisms removes much more lipid from these than from Gram-positive forms. The extractability of lipids from cells of Staphylococcus epidermidis increased when they became Gram-negative through aging. The infrared spectrum of the lipids extracted from these Gram-negative Staphylococci remained the same as that of the Gram-positive cells. It was further noted that high polarity characteristics and mutual miscibility in aqueous and lipid solvents are requirements of the decolorizing solvent.The Gram staining reaction of a cell appears to be related to the manner in which some of its lipids are bound to other components of the cell and the ease or difficulty with which the lipids are separated from lipoprotein and other complexes by certain polar solvents.
PYRIDOXINE DEFICIENCY AND CHOLESTEROGENESIS IN THE CHICK
Authors: Lupien P. J. , Migicovsky B. B.
Published: December 2009

Physiological disturbances common to B6 avitaminosis were clearly manifested when 3-day-old chicks were fed a pyridoxine-deficient diet for 8 days. Body and liver weights were depressed but were restored to quasi-normal states after 4 days of pyridoxine supplementation (3 mg/lb diet). The elevated serum cholesterol levels observed were the result of a failure of this parameter to fall at the rate characteristic of a well-fed bird and not to a specific elevation of the serum cholesterol above the starting conditions. Liver cholesterol levels were unaffected by the hypovitaminosis. Pyridoxine supplementation rapidly re-established normal serum cholesterol levels.The significant depression of C14-acetate incorporation into liver and serum cholesterol of 7-day-old pyridoxine-deficient chicks was maintained for the next 8 days. Mevalonate-2-C14 incorporation into liver cholesterol was not significantly depressed by the hypovitaminosis at any time during the study. Unlike the controls, mevalonate-2-C14 incorporation into serum cholesterol was significantly lowered in the 11-day-old pyridoxine-deficient chicks, but not at any other time during the study.The significance of these findings and the possible relationship between these factors are discussed.
IMMUNOCHEMICAL PROPERTIES OF THYROID PROTEINS
Authors: Perelmutter L. , Stephenson N. R.
Published: December 2009

Saline extracts obtained from both beef and hog thyroid glands were chromatographed on Sephadex G-200. An ultracentrifugal and immunochemical examination of the fractions showed that subfractions which possessed the 19 S component and a sufficient concentration of the 25 S component gave rise to two precipitin bands by the agar gel diffusion technique. Immunoelectrophoretic studies indicated that these antigens migrated in the region of α2globulins. In addition, it was found that subfractions which contained both the 19 S and 25 S components had higher extinction coefficients at 280 mμ and lower OD280/OD260ratios than those in which the 19 S component occurred alone. From these results, it can be suggested that the 19 S and 25 S components have different immunochemical and spectrophotometric properties.
CHROMATOGRAPHIC SEPARATION OF PHOSVITIN, α- AND β-LIPOVITELLIN OF EGG YOLK GRANULES ON TEAE-CELLULOSE
Authors: Radomski M. W. , Cook W. H.
Published: December 2009

The two components of lipovitellin and the three major components of yolk granules, phosvitin, α- and β-lipovitellin, have been separated by gradient elution chromatography on TEAE-cellulose. A 0.2 M phosphate buffer (pH 6.8) had the necessary ionic strength to dissolve these proteins and when applied in this solvent all components except β-lipovitellin were retained by the column. A linear gradient of ionic strength (limit buffer 0.2 M phosphate plus 0.5 M NaCl) was used to remove the other components. Recovery was essentially complete and the composition and properties of the individual components were similar to those obtained by previous chromatographic methods that gave only partial recovery. An additional component eluted after α-lipovitellin and before phosvitin, previously observed in Dowex-1 separations, was also observed by the present method. The composition, sedimentation behavior, and absorption spectra of this component indicate that it is a soluble complex of phosvitin and lipovitellin. When granules are dissolved in alkaline solvents (pH 9.4) of low ionic strength (0.05), phosvitin is not evident as a separate component during ultracentrifugation, but appears as the ionic strength is increased.
CONGO RED AS AN INDICATOR FOR MAGNESIUM: I. A COMPARISON OF SERUM VALUES USING CONGO RED AND TITAN YELLOW
Authors: Ellis N. J. , Bishop D. M.
Published: December 2009

Congo red was successfully substituted for titan yellow in the colorimetric estimation of magnesium in serum by using 50 μg/ml congo red as the working standard (i.e., halving the dye concentration), and by determining the optical density at 560 mμ in a Beckman DU spectrophotometer.Thirteen serum samples were obtained from 12 healthy subjects, and the magnesium in each sample was estimated with both congo red and titan yellow to provide a comparision of the methods. The mean values obtained by these methods were: 1.95 mg/100 ml or 1.61 meq/l. with congo red, and 2.15 mg/100 ml or 1.77 meq/l. with titan yellow.
THE EFFECT OF CARBON TETRACHLORIDE ON HEPATIC LIPID METABOLISM
Authors: Rubenstein Bernard , Rubinstein David
Published: December 2009

The effect of the administration of varying doses of CCl4upon the level of hepatic lipid fractions was investigated. The hepatic cholesterol esters are greatest at low doses of CCl4, while the hepatic triglycerides and serum transaminase levels continue to rise as increasing amounts of CCl4are administered. The amount of liver triglycerides is significantly increased within 2 hours after CCl4administration, while the hepatic cholesterol ester level and serum transaminase activity are not elevated until 6 hours. An increase in the rate of incorporation of intravenously administered acetate-1-C14into hepatic triglycerides occurred within 3 hours after CCl4treatment, but no increase was noted in cholesterol and cholesterol ester radioactivity until an additional 3 hours had elapsed.The treatment of CCl4-intoxicated rats with phenoxybenzamine, although decreasing necrosis, does not prevent the accumulation of hepatic lipids.Slices of liver from CCl4-intoxicated animals incorporate acetate-1-C14more rapidly into cholesterol esters and less rapidly into cholesterol and triglycerides than liver slices from control animals. The presence of CCl4in the atmosphere above the liver slices from untreated animals induced an increase in acetate-1-C14incorporation into both cholesterol esters and free fatty acids and a decrease in incorporation into cholesterol. The incorporation of radioactivity into triglycerides was not affected.
STUDIES ON THE ACTIVATION OF PLASMINOGEN: II. ON THE NATURE OF THE PROAGTIVATOR
Authors: Gutman M. , Rimon A.
Published: December 2009

Insoluble derivative of streptokinase was prepared by coupling it to diazotized copolymer of p-amino phenyl alanine and leucine. This derivative was incubated with plasminogen, and the mixture was then analyzed for its plasminogen, plasmin, proactivator, and activator contents.It was found that, upon interaction with streptokinase (insoluble), plasminogen disappeared from the mixture, giving rise to plasmin and (or) activator, according to the experimental conditions. The proactivator also disappeared, but its behavior was parallel to the sum of behaviors of plasminogen and plasmin, rather than to the behavior of any one of them alone.The results led to the conclusion that both plasminogen and plasmin may be proactivators in the sense that they may form an activator upon addition of streptokinase.
FATTY ACIDS IN SOME INSECT AND SPIDER FATS
Authors: Barlow J. S.
Published: December 2009

Chromatographic analysis of the fats of 30 species of Insecta and 2 species of Arachnida showed specific differences, and also two characteristics apparently related to existing taxa: a high concentration of myristic acid in fats of Aphidoidea, and a high concentration of palmitoleic acid in Diptera. A possible relationship between the high palmitoleic acid content of the fat of Agria affinis (Fallén) (Diptera: Sarcophagidae) and its lack of requirement for polyunsaturated fatty acids is suggested.
EXTRACELLULAR POLYSACCHARIDES OF SERRATIA MARCESCENS
Authors: Adams G. A. , Martin S. M.
Published: December 2009

Growth of Serratia marcescens on sucrose, D-glucose, D-galactose, and D-xylose as carbon sources did not affect the composition of the extracellular polysaccharides significantly. D-Glucose was the major component with lesser amounts of D-mannose, heptose, L-fucose, and L-rhamnose. Rhamnose did not appear until near the end of the active growth period and increased proportionately more than the other sugars thereafter. From the culture filtrate after 20 hours growth on sucrose, two acidic polysaccharides were isolated. They were markedly different in composition and electrophoretic behavior although both contained glucose as their major component. One was characterized by a relatively high content of rhamnose and heptose, the other by the presence of mannose; both contained glucuronic acid. Other impure polysaccharides were isolated from the culture filtrate. It seems likely that S. marcescens produced a spectrum of rather similar extracellular polysaccharides of which the two isolated ones comprise the main types.
NITROGEN BALANCES OF YOUNG MEN FED SELECTED AMINO ACID PATTERNS: I. FAO REFERENCE PATTERN, A MODIFICATION OF THE FAO REFERENCE PATTERN, AND WHEAT FLOUR PATTERN
Authors: Watts Johnnie H. , Tolbert Bernadine , Ruff Willie L.
Published: December 2009

Nitrogen balances were determined for six young men fed three amino acid patterns: the FAO reference pattern, a modification of the FAO pattern in which methionine was decreased and phenylalanine increased isonitrogenously, and the wheat pattern. Total N intake was approximately 10 g. The lowest intakes of the FAO reference pattern amino acids found to be adequate for the support of N equilibrium or positive N balance contained 320 mg tryptophan in the case of two subjects, 280 mg tryptophan for three subjects, and 240 mg tryptophan for one subject. Comparison of group mean N retentions for the FAO and the modified FAO patterns indicated that the two patterns were of equal value. When the FAO reference and wheat patterns were fed to provide comparable amounts of lysine, the limiting amino acid of wheat protein, group mean N retentions were 0.42 and 0.41 g, respectively. When the same two patterns were fed to provide an equivalent amount of essential amino acid N and the chief source of amino acids was intact wheat protein, group mean N retentions were 0.62 g for the FAO reference pattern, and 0.41 g for the wheat pattern; statistically, this difference is not significant. From 0.63 to 0.84 g essential amino acid N provided as FAO reference pattern was adequate to maintain N equilibrium or a slight positive balance.
THE EFFECT OF ALDOSTERONE ON ELECTROLYTES IN MUSCLE, KIDNEY CORTEX, AND SERUM
Authors: French I. W. , Manery J. F.
Published: December 2009

This investigation was carried out on 128 young rats maintained on diets varying in sodium and potassium content. For all experiments the rats were divided into at least three groups: intact, adrenalectomized (ADX), and ADX given dl-aldosterone (10 or 25 μg) daily for 5 days. In rats on a normal diet serum Na fell from 151 to 134 meq/l. and serum K rose from 7 to 11 meq/l. as a result of adrenalectomy; muscle Na decreased from 119 to 97 meq/kg dry weight and muscle K increased somewhat. In general, kidney cortex Na and K changed in the same direction as the muscle cations. On all high-Na diets muscle Na increased in ADX rats while serum Na remained constant. Tissue K changes were somewhat more variable than alterations in tissue Na. The principal finding was that the administration of aldosterone prevented most of the tissue cation changes caused by adrenalectomy regardless of their direction. Thus a dual control of tissue electrolytes by the hormone is suggested, namely that aldosterone might control tissue cation concentrations indirectly through its influence on plasma levels, and also directly by inhibiting the cellular sodium pump.
THE ISOLATION OF BEEF SPHINGOMYELINS
Authors: Spencer W. A. , Schaffrin R.
Published: December 2009

A method was developed for the quantitative isolation of tissue sphingomyelins. Total lipid extracts of tissues were subjected to selective hydrolysis to destroy ester phosphatides and plasmalogens. The water-soluble hydrolysis products were removed by solvent fractionation. The sphingomyelins were separated from other lipids on silicic acid columns.Sphingomyelins were prepared from beef heart, lung, kidney, adrenal, brain, liver, and adipose tissue. The sphingomyelins were analyzed by thin-layer chromatography, paper chromatography of hydrolysis products, and infrared spectroscopy. Fatty acids were analyzed by gas–liquid chromatography.Methods for preparation and analysis of sphingomyelins are discussed.
STUDIES ON THE LIPID METABOLISM OF THE CHICK EMBRYO
Authors: Noble R. C. , Moore J. H.
Published: December 2009

A study was made of the amounts and fatty acid compositions of the cholesterol esters, phospholipids, and triglycerides present in the yolk of the fertile unincubated egg and in the yolk, liver, and extrahepatic tissues of the chick embryo at various stages of development. Esterification of cholesterol, mainly with oleic acid, occurred in the yolk during incubation. There appeared to be a preferential absorption from the yolk sac of phospholipids rich in docosahexaenoic acid. Considerable amounts of cholesterol esters, of which 80% was cholesterol oleate, accumulated in the embryonic liver. The liver phospholipids contained more stearic, arachidonic, and docosahexaenoic acids, and less palmitic and oleic acids, than did the yolk phospholipids. Docosahexaenoic acid occurred in a surprisingly high concentration in the liver triglycerides. The extrahepatic triglycerides contained more palmitic and C18polyunsaturated acids, but less docosahexaenoic acid, than did the liver triglycerides. The concentration of oleic acid in the extrahepatic cholesterol esters was much less than in the liver cholesterol esters. The extrahepatic phospholipids contained more arachidonic and docosahexaenoic acids, but less oleic acid, than did the yolk phospholipids. The implications of these findings are discussed in relation to the general lipid metabolism of the chick embryo.
THE METABOLISM OF 9-ARABINOSYL-6-MERCAPTOPURINE IN NORMAL AND NEOPLASTIC TISSUES
Authors: Kimball A. P. , LePage G. A. , Bowman B.
Published: December 2009

Arabinosyl-6-mercaptopurine (ara-6-MP) was found to increase the survival time of mice bearing 6-mercaptopurine (6-MP)-sensitive or 6-MP-resistant tumors. Studies with the radiosulfur-labeled drug in mice showed that the drug was rapidly cleared from the blood, distributed throughout the tissues, and relatively rapidly excreted in the urine. Arabinosyl-6-mercaptopurine was neither cleaved to 6-mercaptopurine by the Ehrlich ascites tumor nor converted to nucleotide to any appreciable extent under the conditions studied. Arabinosyl-6-mercaptopurine at a dosage level of 300 mg/kg produced a minimal inhibition of orotic acid-6-C14incorporation into the DNA cytosine of the Ehrlich ascites tumor. No effect on the incorporation of glycine-2-C14into acid-soluble or nucleic acid purines of the Ehrlich ascites tumor was noted at this dosage level. No toxicity has been observed with the doses of ara-6-MP studied (300 mg/kg).
KINETIC STUDIES ON ACID PHOSPHATASE IN TRIBOLIUM CONFUSUM DUVAL
Authors: Chaudhary K. D. , Moorjani S. , Lemonde A.
Published: December 2009

The biochemical characteristics of acid phosphomonoesterase in Tribolium confusum homogenate have been determined. Zero-order reaction occurs for 30 minutes, with 10−3 M final concentration of phenyl phosphate at an optimum pH of 6.4. Michaelis constant (Km) under the optimal conditions is 6.34 × 10−3 M. Maximum enzyme activity is obtained at 40 °C, and the activation energy (ΔE) is 13,000 cal/mole, within the limits of optimum temperature. Inorganic phosphate inhibits competitively and Kivalue is 3.45 × 10−3 M. Partial inhibition by fluoride is shown. Apparent effect of metallic ions also has been demonstrated.Comparison of these results with those reported in the literature for several other species of insects, as well as with those in certain mammalian systems, has been discussed.
FURTHER OBSERVATIONS ON THE FUNCTIONAL ZONATION OF THE ADRENAL CORTEX
Authors: Stachenko J. , Giroud C. J. P.
Published: December 2009

In the isolated zona glomerulosa of beef adrenal cortex, progesterone, 11β-hydroxyprogesterone, 11-desoxycorticosterone, and corticosterone are precursors of aldosterone. 18-Hydroxylation is probably a rate-limiting step in the biosynthesis of aldosterone. At low concentration Metopirone selectively inhibits 18-hydroxylase activity. The sequence of hydroxylation of the steroid molecule proceeds effectively in the order 11, 17, 21. The main action of ACTH is to increase cortisol production by the fasciculate–reticularis. In the present in vitro system, the production of aldosterone by the glomerulosa is not affected by either ACTH or angiotensin.
THE ISOLATION AND PURIFICATION OF A TRYPSIN INHIBITOR FROM WHOLEWHEAT FLOUR
Authors: Shyamala G. , Lyman R. L.
Published: December 2009

An impure concentrate of a trypsin inhibitor was prepared from a commercial sample of wholewheat flour by ammonium sulfate precipitation. The impure inhibitor was heat-labile and did not inhibit pepsin or α-chymotrypsin activity. When the crude inhibitor was chromatographed on carboxymethyl cellulose, a single protein peak that was about 20 times more active than the original impure inhibitor preparation was obtained.Uultracentrifugal sedimentation patterns and moving-boundary electrophoresis indicated that the material isolated on the carboxymethyl cellulose was nearly homogeneous. In comparison with other known trypsin inhibitors that have been isolated in nearly pure form, wholewheat trypsin inhibitor appears to have a low specific activity.
BIOCHEMICAL STUDIES ON A MODIFIED AND NORMAL CHOLINESTERASE FOUND IN THE LEVERKUSEN STRAINS OF THE TWO-SPOTTED SPIDER MITE TETRANYCHUS URTICAE
Authors: Voss G. , Matsumura F.
Published: December 2009

The properties of two different cholinesterases present in the organophosphorus-insecticide-resistant Leverkusen strain and its susceptible counterpart were investigated and compared. The cholinesterase of the Leverkusen resistant strain is characterized by a low sensitivity to organophosphate inhibitors, as is represented by an increase in the enzyme-inhibitor affinity constant (KI). This statement is in accordance with the finding that the ratio of the Michaelis constants for the two cholinesterases is 4, whereas the ratio of the respective maximum velocities (vmax) was only 1.2. Since those organophosphate inhibitors are known to attack only the esteratic site of the cholinesterase, the above finding can be interpreted to mean that the cholinesterase of the resistant strain possesses an abnormally weak esteratic site in terms of its affinity for the substrate as well as for the inhibitor. To investigate the extent of alteration of the esteratic site, a series of organophosphate poisons was tested against these cholinesterases. It was found that the interstrain difference was maximal with the shortest dialkyl side chain of the phosphorus atom, and that the difference decreased with the increase in the dialkyl carbon chain length. Similar findings were made when eholinesters with different acyl groups were tested as substrates. Propionylcholine was hydrolyzed at a faster rate than acetylcholine in both mite strains, and distinct interstrain differences in the cholinesterase activity towards these substrates were observed; with butyrylcholine, however, this interstrain difference was undetectable. Properties of mite cholinesterase were compared with those of insect and mammalian cholinesterases.
THE ALLOSTERIC NATURE OF NAD-SPECIFIC ISOCITRIC DEHYDROGENASE FROM ASPERGILLI
Authors: Chan Marianne F. , Stachow C. S. , Sanwal B. D.
Published: December 2009

A kinetic study of the NAD-dependent isocitric dehydrogenase from Aspergillus niger (citrate excretor) and A. flavus (nonexcretor) has been made. The enzyme from both sources is markedly and specifically activated by citrate. Analysis of initial velocity data shows that the enzyme possibly has a distinct allosteric site that can bind both isocitrate and citrate, and an active site that is specific for isocitrate. It is conjectured that citrate accumulation by A. niger may be due to a 'desensitization' of the allosteric site of the enzyme by environmental factors.
BIOSYNTHESIS OF NUCLEOTIDES IN WHEAT: III. PURINE AND PYRIMIDINE NUCLEOTIDES FROM P32-LABELLED PHOSPHATE
Authors: Robern H. , Wang D. , Waygood E. R.
Published: December 2009

Phosphate labelled with P32 was fed to viable wheat embryos with and without 5-amino-4-imidazole carboxamide (AICA). The cold perchloric acid fraction was treated with Norit A; the adsorbed nucleotides were eluted by pyridine–alcohol and subjected to chromatographic analysis for identification. Approximately 30% of the label in the soluble fraction was incorporated into identifiable purine and pyrimidine nucleotides. AICA had no effect on the amount of incorporation. This study shows the existence of a pool of free nucleotides in wheat embryos.
THE EFFECT OF DDT ON THE LIVER CARBOXYLESTERASE AND VITAMIN A UTILIZATION OF MOTHER RATS AND THEIR YOUNG
Authors: Read Sheila I. , Murray T. K. , McKinley W. P.
Published: December 2009

DDT (100 p.p.m.) was added to the diet of female rats that were then bred to males receiving the same diet. Liver carboxylesterase and liver and kidney vitamin A levels were measured in the dams and their young at parturition and at weaning.DDT did not have any adverse effect on the breeding performance of the adults or on the vitamin A stores of the newborn or weanling rats. Vitamin A stores of the dams were reduced by the pesticide. Liver carboxylesterase increased greatly between birth and weaning and remained almost constant thereafter. DDT caused a marked increase in liver carboxylesterase over and above that which occurred during growth.
A RIBOSOMAL PEPTIDASE FROM ESCHERICHIA COLI B
Authors: Matheson A. T. , Tsai C. S.
Published: December 2009

Properties of a peptidase present in E. coli ribosomes have been studied. The enzyme is tightly bound to the ribosomes, as indicated by repeated washings and centrifugations, sucrose density gradient centrifugations, and electrophoresis on cellulose acetate. The level of enzyme activity in the 30 S particles is twice that found in the 50 S particles. When the ribosome structure is disrupted by enzymic or chemical means, the peptidase behaves similarly to the bulk of the ribosomal protein.
PHYSICOCHEMICAL PROPERTIES OF α-CRYSTALLIN FROM CALF LENS COMPARED TO THOSE FROM OX LENS
Authors: Niyogi Salil K. , Koenig Virgil L.
Published: December 2009

α-Crystallin was isolated from calf lenses and purified by repeated precipitation at its isoelectric point. Electrophoretic mobilities, intrinsic viscosities, and partial specific volumes were determined at pH's 2.0, 7.7, and 9.1, ionic strengths 0.1, 0.2, and 0.3, respectively. Sedimentation studies were performed at pH 2.0, μ 0.10, and at pH 9.1, μ 0.30. A light-scattering study was done at pH 7.7, μ 0.20. The viscosity and sedimentation studies at pH 2.0 indicate an unfolding of the protein ultimately leading to dissociation. This dissociation is not evident in electrophoretic studies, which show a single boundary at different pH's and ionic strengths. Molecular weights and dimensions have been calculated from sedimentation, viscosity, and partial specific volume data at pH 9.1, μ 0.30.The physicochemical properties of calf α-crystallin have been compared with those of ox α-crystallin. The electrophoretic and sedimentation studies indicate similar degrees of homogeneity of the α-crystallin preparations obtained from the two sources. It appears from these studies that calf α-crystallin is larger and more asymmetric than ox α-crystallin at pH's 2.0 and 9.1, ionic strengths 0.10 and 0.30, respectively. At pH 7.7, μ 0.20, calf α-crystallin, although having nearly the same size, is definitely more asymmetric than ox α-crystallin.
A COMPARATIVE STUDY OF THE PROTEINS IN NORMAL MECONIUM AND IN MECONIUM FROM MECONIUM ILEUS PATIENTS
Authors: Schachter Harry , Dixon Gordon H.
Published: December 2009

Starch gel electrophoresis and immunoelectrophoresis have been used to confirm previous reports that the highly viscous meconium obtained from patients with meconium ileus is rich in albumin and also contains alpha-, beta-, and gamma-globulins. Normal meconium contains only small amounts of these proteins. It is shown that normal meconium contains a TCA-soluble mucoprotein that is resistant to digestion by the combined action of the proteolytic enzymes trypsin and chymotrypsin. Meconium ileus meconium contains this mucoprotein component in a bound state; it can be released by proteolytic digestion with trypsin and chymotrypsin, or by phenol. Enzymic digestion of meconium ileus meconium destroys all the protein components of abnormal meconium except the resistant mucoprotein, thereby converting the electrophoretic pattern of meconium ileus meconium into a normal pattern. It is suggested that meconium ileus meconium is identical with the contents of the upper small bowel of any normal fetus and that meconium ileus can result when the mechanism of intestinal proteolysis is defective. In an attempt to determine whether meconium ileus meconium contains an abnormal mucoprotein that may be responsible for the viscosity of this material, phenol extraction was used to prepare the mucoprotein from both normal meconium and meconium ileus meconium. About 25% of the dry weight of normal meconium consists of this mucoprotein but the yield of mucoprotein from abnormal meconium is only 2–6% of the dry weight. The relatively low viscosity of mucoprotein from meconium ileus meconium and its presence in only small amounts in the abnormal meconium indicate that it does not play a direct role in the etiology of meconium ileus. The chemical composition of this mucoprotein shows it to be a sialomuco-polysaccharide. Although there are consistent differences between preparations from normal and abnormal meconium, these differences are attributed to partial proteolysis of mucoprotein in the normal digestive tract and are probably not related to cystic fibrosis.
A STUDY OF THE THYROID PROTEIN METABOLISM OF THE THIOURACIL-TREATED RAT
Authors: Perelmutter L. , Watanabe H. , Stephenson N. R.
Published: December 2009

Oral administration of 2-thiouracil, for periods up to 28 days, greatly affected the soluble proteins of the rat thyroid gland. After 2 days, the iodine/protein ratio declined to less than half that present in the normal group. Ultracentrifugal analyses of the thyroid extracts showed a decrease in the 19 S thyroglobulin component, and a progressive increase in the 3 S component. After 7 days of treatment with 2-thiouracil, the 3 S component was the major protein constituent. The 11 S component rose to a maximum at 7 days and subsequently declined. Chromatographic fractionation of some of the thyroid extracts on Sephadex G-200 revealed similar changes in protein distributions. Both the whole thyroid extracts and their Sephadex G-200 fractions were examined by immunoelectrophoresis and the 19 S, 11 S, and 3 S components were characterized as having electrophoretic mobilities in the albumin-α1, α2, and α1-β regions respectively. By the micro-Ouchterlony agar gel technique, the 3 S component did not cross-react with the 19 S or 11 S components. In addition, the 19 S and (or) 11 S components of the 14-day group showed only partial cross-reaction with those of the normal group.
BOUND γ-AMINOBUTYRIC AND OTHER AMINO ACIDS IN BRAIN
Authors: Elliott K. A. C. , Khan R. Tariq , Bilodeau F. , Lovell R. A.
Published: December 2009

Previous work has shown that when brain is homogenized in saline medium, part of the γ-aminobutyric acid (GABA) in the tissue is found in free solution and part is bound or occluded in particulate material. In the present work it is shown that the GABA content of solid brain or anaerobic brain suspensions increases with time and the increase is all in the free form. In suspensions in the presence of oxygen and glucose no increase in GABA occurs. A lower proportion of the GABA is found in bound form if the suspension is prepared in the cold rather than at room or body temperature. The amount found in bound form is sharply dependent on pH. The optimum is about pH 7. If brain is homogenized in plain sucrose solutions, or if potassium is substituted for sodium in saline solution, the amount of bound GABA found is half that found in isosmotic sodium chloride. The normal amount remains bound if 10 mM sodium ion or 5 mM calcium ion is present in the sucrose solution. Glutamic acid, glutamine, alanine, and aspartic and acetylaspartic acids are also partly bound in brain. The amounts of these amino acids as well as of GABA found in brain frozen in situ are considerably lower than in brain which has been excised rapidly after death but without freezing.
FATTY ACID AND GLYCERIDE GLYCEROL SYNTHESIS FROM GLUCOSE DURING HIGH RATES OF GLUCOSE UPTAKE IN THE INTACT RAT
Authors: Freitas A. S. W. de , Depocas Florent
Published: December 2009

The extent of incorporation of glucose carbon into total lipids and component fatty acid, neutral glyceride glycerol, and phosphoglyceride glycerol moieties of carcass, liver, and epididymal tissue has been measured in 20 rats under conditions of constant plasma glucose concentration and specific activity. Rates of fatty acid synthesis from glucose and absolute rates of synthesis have also been estimated. Each rat received 750 mg glucose per hour by continuous infusion. The incorporation of glucose carbon into carcass, liver, and epididymal fat was, respectively, 6.2, 0.75, and 0.06% of the total glucose carbon taken up by the rat tissues. Fifty percent of the C14found in total lipids of carcass and liver was in the fatty acid fraction. Corresponding glyceride glycerol moieties contained approximately 40% of the total activity. The low level of incorporation of glucose carbon into fatty acids and glyceride glycerol indicates that lipogenesis from glucose can only account for a small proportion of the total glucose taken up by the tissues, even at high rates of glucose uptake. Rates of synthesis from glucose of carcass and liver fatty acids were estimated as 1.5 and 0.11 mmoles fatty acid per tissue per day respectively, with corresponding half-lives of 57 and 7.6 days. Absolute rates of fatty acid synthesis were estimated as 2.6 and 0.55 mmoles fatty acid per day for carcass and liver tissue respectively, with corresponding half-lives of 34 and 4.6 days.
GLYCOGEN PHOSPHORYLASE AND GLYCOGEN SYNTHETASE ACTIVITY IN RED AND WHITE SKELETAL MUSCLE OF THE GUINEA PIG
Authors: Stubbs Sydney St. George , Blanchaer M. C.
Published: December 2009

Glycogen phosphorylase (α-1,4-glucan:orthophosphate glucosyltransferase) and glycogen synthetase (UDPG:α-1,4-glucan α-4-glucosyltransferase) have been examined in red and white skeletal muscle of the guinea pig. Histochemically phosphorylase was found to be more active in white than in red muscle fibers but no difference in glycogen synthetase could be detected between the fiber types. However, quantitative determinations showed that total glycogen synthetase activity (I + D) was higher in red than in white muscle (1.46 ± 0.14 S.E.M. vs. 0.71 ± 0.09 μmoles/minute per g wet weight at 37°). The converse relationship held for total phosphorylase activity (a + b), which was greater in white than in red muscle (19.24 ± 2.93 vs. 10.43 ± 2.34 μmoles/minute per g wet weight at 30°). The phosphorylase a level of 3.63 ± 0.96 in red muscle at rest was similar to that of 5.44 ± 1.19 in resting white muscle. Stimulation produced a significant conversion of phosphorylase b to a only in white muscle. After 30 seconds stimulation with 1-volt impulses of 20 milliseconds duration at a rate of 20 pulses per second, the phosphorylase a activities of red and white muscle were respectively 3.72 ± 1.88 and 16.66 ± 1.79. After stimulation the glycogen synthetase values in white and red muscle were 1.02 ± 0.07 and 1.72 ± 0.11 respectively.