bluuebunny/crossref_metadata_2025_split huggingface dataset:
INHIBITION OF BACTERIAL AND MAMMALIAN CHOLINE ACETYLTRANSFERASES BY STYRYLPYRIDINE ANALOGUES
Authors: White H. L. , Cavallito C. J. 
Published: October 2006

Abstract—Choline acetyltransferase was extracted from Lactobacillus plantarum by relatively gentle procedures involving penicillin treatment, osmotic shock and passage through a French pressure cell. After partial purification, the extract was compared with choline acetyltransferase of calf caudate nucleus for kinetic properties and response to a class of inhibitors which consists of analogues of styrylpyridine. Both enzymes obeyed a sequential mechanism with Michaelis constants for the bacterial enzyme, Km= 8 μm vs. acetyl‐CoA and 0·44 mm vs. choline; and for the caudate nucleus enzyme, Km= 15 μm vs. acetyl‐CoA and 0·8 mm vs. choline. Both were stabilized by dithiothreitol and EDTA.The extracts differed in that the bacterial enzyme was more labile and apparently was susceptible to conformational changes, which modified its response to the styrylpyridinetype inhibitors. The use of intact cells of Lactobacillus plantarum as an in vivo system for studying the inhibition of choline acetyltransferase by styrylpyridines was possible only for non‐quaternary analogues, which exist as an equilibrium mixture of charged and uncharged species.
THIAMINE PYROPHOSPHATASE ACTIVITY IN A FRACTION RICH IN GOLGI‐LIKE STRUCTURES FROM CRUSHED SCIATIC NERVE OF THE CAT1
Authors: De Iraldi Amanda Pellegrino , Rodríguez Georgina , Arnaiz De Lores 
Published: October 2006

Abstract—The activity of thiamine pyrophosphatase was determined in segments and segment subfractions from normal and crushed sciatic nerves of the cat. Activity of the enzyme was increased in segments near the site of compression. The highest activity of the enzyme was in a fraction rich in tubular and vesicular elements resembling those observed in intact compressed nerves. On morphological grounds these structures have been interpreted as originating from Golgi‐like structures.
METABOLIC CHARACTERISTICS OF MITOCHONDRIA ISOLATED FROM RABBIT BRAIN1
Authors: Von Korff R. W. , Steinman Sondra , Welch Annemarie S. 
Published: October 2006

Abstract— Data on the metabolic characteristics of mitochondria from rabbit brain have been obtained using low concentrations (100–300 μm) of 14C‐labelled substrates of the Krebs tricarboxylic acid cycle. Oxygen consumption was measured polarographically with a Clark‐type electrode. Products of the reactions were separated by chromatography on Dowex‐1 columns. Data are reported for relative respiratory quotients of various substrates, respiratory control ratios, accumulation of 14C in various tricarboxylic acid cycle intermediates and the effect of malate and several inhibitors on these parameters. The data have been compared with similar experiments on mitochondria from rabbit heart.Mitochondria from rabbit brain differ substantially from heart mitochondria: those from brain have a very low capacity for oxidation of acetate and other short chain fatty acids; they do not form j3‐hydroxybutyrate; they produce substantial amounts of α‐ketoglutarate and require added dicarboxylic acid to yield a maximum respiratory quotient. Like those from heart, brain mitochondria have a high capacity for pyruvate oxidation and a low Km for this substrate. The results have been discussed and compared with work reported by other investigators.
DEPENDENCE OF FAST AXOPLASMIC TRANSPORT IN NERVE ON OXIDATIVE METABOLISM
Authors: Ochs S. , Hollingsworth D. 
Published: October 2006

Abstract—A crest of labelled activity moving down the sciatic nerve at 401 ± 35 mm/day after injection of the L7 dorsal root ganglion of the cat with L‐[3H]leucine characterizes fast axoplasmic transport of materials and has been studied with regard to its dependence on oxidative metabolism. Transport of labelled materials in vitro occurred if the nerve was supplied with O2 or 95 % O2+ 5 % CO2. Transport was not dependent upon continuity of the fibres with the ganglionic soma. Asphyxiation (N2) rapidly blocked fast transport in vitro. Likewise NaCN or dinitrophenol in an O2 atmosphere both effectively block fast transport within 15 min. Tetrodotoxin and procaine, agents which block excitation of the membrane, had no effect on fast transport. The inference is that oxidative metabolism supplies the energy required by the molecular mechanism underlying fast axoplasmic transport.
POST MORTEM CHANGES IN EXTRACTABLE PROTEIN AND IN TISSUE pH IN THE GUINEA PIG BRAIN
Authors: Cain D. F. , Kappy M. S. 
Published: October 2006

Abstract—Guinea pigs were killed by asphyxiation with nitrogen and the soluble proteins were extracted from the brain at various times post mortem. The quantity of extractable brain protein decreased by 21 per cent when the animals remained at room temperature for 2 h post mortem. This decrease was not a consequence of extensive proteolysis or variations in blood volume but was probably a result of precipitation. After death, the pH of the brain fell rapidly to a minimum of ∼6CE4 within about 35 min. Examination of the patterns of brain proteins after acrylamide gel electrophoresis showed a concomitant decrease in the content of several protein bands.
CHANGES OCCURRING IN THE CHEMICAL COMPOSITION OF THE CENTRAL NERVOUS SYSTEM DURING FOETAL AND POST‐NATAL DEVELOPMENT OF THE SHEEP
Authors: Patterson D. S. P. , Sweasey D. , Hebert C. Nancy 
Published: October 2006

Abstract(1) The chemical composition of the CNS (separated into cerebrum, cerebellum, brain stem and spinal cord) was determined in sheep during foetal and post‐natal development and in adults.(2) The spinal cord differed from the remainder of the CNS in growing more after the period studied (50‐day‐old foetuses to 5‐week‐old lambs) than before it. This was largely attributable to lipid accumulation.(3) Chemical growth (accumulation of DNA, protein and lipid) proceeded linearly in spinal cord, logarithmically in cerebrum and cerebellum while in brain stem growth was described by a sigmoid function.(4) Fat‐free dry matter, protein, total lipid, cholesterol and phospholipid concentrations increased progressively in all parts of the CNS but DNA concentrations changed little. In the cerebrum alone there was an increase in DNA concentration during maturation suggesting an increased cell population. Cholesterol was present predominantly in the free form but esters were detected in foetal tissues from 70 up to 120 days gestation.(5) Cerebroside, the characteristic lipid of myelin, increased in concentration soon after 85 days of gestation, up to which point very low values were recorded, the rate varying according to the region of the CNS examined. Rates of increase in total regional cerebroside content were used to identify periods of myelination and the results suggest that there are two periods of peak activity, one about 20 days before birth and the other at 10‐20 days after birth.(6) The composition of lipids added during the two phases of myelination and during maturation were characteristically different. In the spinal cord, lipid analyses best reflect changes in myelin composition.
STUDIES ON THE METABOLIC DETERMINANTS OF D‐GALACTOSE‐INDUCED NEUROTOXICITY IN THE CHICK1
Authors: Kozak L. P. , Wells W. W. 
Published: October 2006

AbstractThe contents of galactose, galactitol, galactose 1‐phosphate, UDP‐galactose and UDP‐glucose in the brains of chicks fed a diet containing 40 % (w/w) D‐galactose were determined at regular intervals during a 48 h period which terminated in convulsive activity and death of the animals. Although levels of galactose and galactitol were markedly elevated, UDP‐galactose and UDP‐glucose levels were not significantly increased. The level of galactose 1‐phosphate rose to 1‐3 μg/g of fresh tissue by 14 h but gradually diminished until, at 48 h, the content was 0‐25 μg/g. The metabolic turnover of these compounds, as shown by labelling experiments with inorganic [32P]phosphate and [U‐14C]galactose, indicated that galactose 1‐phosphate and UDP‐galactose were rapidly metabolized, yet relatively little galactose was utilized by the brain as a source of energy. These observations have prompted us to propose a mechanism for the turnover of galactose 1‐phosphate that involves cyclical phosphorylation and dephosphorylation reactions in the brains of galactose‐fed chicks. In support of this hypothesis, we have identified phosphatase activity which has a relatively low Km value for galactose 1‐phosphate (0‐06‐0‐07 mM) in virtually all subcellular fractions of homogenates of chick brain. Maximum activity of the phosphatase is several‐fold greater than that recorded for galactokinase (EC 2.7.1.6) and galactose 1‐phosphate uridyltransferase (EC 2.7.710) from chicken brain.
CHANGES IN GLUCOSE AND ENERGY METABOLISM IN VIVO IN DEVELOPING RETINAE FROM VISUALLY‐COMPETENT (DBA/1J) AND MUTANT (C3H/HeJ) MICE1
Authors: Lolley R. N. 
Published: October 2006

Abstract— The distribution in vivo of glucose and lactate between the complete or sub‐ divided retina and the blood has been evaluated in DBA and C3H mice during postnatal development. Levels in vivo of several intermediates of glucose and energy metabolism were measured by enzyme‐linked fluorometric assays of freeze‐dried retinae; glucose and lactate were determined in freshly‐drawn plasma. DBA retinae. During the first 20 days of postnatal life, the level of glucose in the plasma rose slightly while that in the retina declined: during this period the level of lactate in the plasma rose and became nearly equal to that in the retina. Changes during development in levels of glucose and glycogen were consistent with the interpretation that the rate of utilization of glucose in vivo is enhanced during early postnatal life. C3H retinae. The levels of glucose and glycogen in vivo were abnormally high throughout the developmental period, whereas levels of lactate were normal. The rise in levels of glucose after the 15th postnatal day was not related to an increase in blood levels of glucose but rather to a decreased utilization of glucose during this period.For the first 10 postnatal days the content of glucose, lactate, ATP and P‐creatine within the photoreceptor layer of C3H retinae were within normal limits. Then, biochemical changes occurred which were secondary to ultrastructural pathology in the photoreceptors. This observation suggested that glucose metabolism and energy production are not involved in the primary aetiology of the inherited disease.
CHANGES IN THE LACTATE AND MALATE DEHYDROGENASE ISOENZYME PATTERNS OF CHICKEN EMBRYO BRAIN AND RETINA
Authors: Pasantes‐Morales H. , Klethi J. , Urban P. F. , Mandel P. 
Published: October 2006

Abstract— Lactate dehydrogenase and malate dehydrogenase isoenzyme patterns of chicken brain and retina have been investigated by cellulose acetate electrophoresis, during embryonic and post‐hatching development. The proportion of M‐type lactate dehydrogenase subunits decreases significantly in brain and retina with development. A marked increase in the H‐type subunits is observed in retina. Lactate dehydrogenase isoenzyme distribution appears to change in both organs in parallel with the metabolic changes of differentiation.Malate dehydrogenase isoenzyme patterns do not reveal any consistent change of the ratio between the mitochondrial and cytoplasmic forms.
CALCIUM‐BINDING PHOSPHOPROTEIN OF PIG BRAIN: EFFECTS OF CATIONS ON THE CALCIUM BINDING
Authors: Wolff D. J. , Huebner J. A. , Siegel F. L. 
Published: October 2006

Abstract—The effects of various cations on the calcium‐binding properties of a brain phosphoprotein have been investigated employing an ultrafiltration binding assay. Sodium, magnesium, barium, strontium and manganese ions were competitive inhibitors of the calcium binding, and their affinity for the calcium‐binding site increased in the order given. Potassium was a non‐competitive inhibitor. Lanthanum, lead, mercuric and cadmium ions precipitated the phosphoprotein from solution. These findings are discussed in relation to a postulated role for the protein as a calcium‐receptor molecule involved in release of neurotransmitters.
THE REGIONAL AND SUBCELLULAR DISTRIBUTION OF CATECHOL‐O‐METHYL TRANSFERASE IN THE RAT BRAIN
Authors: Broch O. J. , Fonnum F. 
Published: October 2006

AbstractCatechol‐O‐methyl transferase (COMT) activities determined in different regions of rat brain showed small variations. Highest activities were found in the hypothalamus and corpora quadrigemina, and lowest activities in the hippocampus and corpus striatum. The regional distribution of COMT was thus at variance with the distribution of DOPA decar‐ boxylase in this study and with the distribution of catecholamines and tyrosine hydroxylase reported in the literature. Determinations of the subcellular distribution of COMT in rat forebrain showed that 50 per cent of the activity was recovered in the high speed supernatant fluid and about 33 per cent in the crude mitochondrial fraction. Further separation of the latter by discontinuous sucrose gradients showed that the particulate COMT was found in the synaptosomal fraction in an occluded form. Full enzyme activity was only obtained after treatment with a detergent or after resuspension in water. After hypo‐osmotic rupture of the crude mitochondrial fraction, COMT was recovered in the cytoplasmic fraction. The subcellular distribution of COMT was very similar to the ones of lactate dehydrogenase and DOPA decarboxylase.The proportions of soluble COMT obtained from homogenates of various regions of the brain differed from that of choline acetyl transferase and DOPA decarboxylase but were similar to that of lactate dehydrogenase. In conclusion, COMT is a cytoplasmic enzyme almost evenly distributed in the CNS. Its distribution does not resemble the distributions of the catecholamines or of the enzymes participating in the synthesis of catecholamines.
EFFECTS OF SODIUM FLUOROACETATE ON THE METABOLISM OF N‐ACETYLASPARTATE AND ASPARTATE IN MOUSE BRAIN
Authors: Nadler J. V. , Horwitch P. , Cooper J. R. 
Published: October 2006

AbstractA subconvulsant dose of sodium fluoroacetate inhibited the metabolic utilization of intracerebrally‐administered N‐acetyl‐l‐[U‐14C]asparticacid and the labelling of glutamine from this precursor in mouse brain, but not the labelling of glutamate or aspartate. A convulsant dose also inhibited the utilization of l‐[U‐14C]aspartic acid. When intraperitoneal injection of a convulsant dose of sodium fluoroacetate was followed by intracerebral injection of N‐acetyl‐l‐[U‐14C]asparticacid, the levels of N‐acetylaspartate, aspartate and glutamate in brain were lowered, while the glutamine content was increased. The specific radioactivity of glutamine relative to that of glutamate was much lower when these compounds were labelled from l‐[U‐14C]aspartic acid than when N‐acetyl‐l‐[U‐14C]aspartic acid was used as the precursor. Intracerebral injection of tracer amounts of l‐[U‐14C]aspartic acid reduced the content of N‐acetylaspartate in brain and raised the glutamine content. Sodium fluoroacetate had no additional effect on the relative specific radioactivity of glutamine or the content of N‐acetylaspartate, aspartate, glutamate or glutamine when l‐[U‐14C]aspartic acid was the precursor. We consider the results to be consistent with a selective inhibition both by sodium fluoroacetate and by exogenous aspartic acid of the tricarboxylic acid cycle in brain associated with the biosynthesis of glutamine. We suggest that the activity of this pathway may regulate the metabolism of N‐acetylaspartate and aspartate.
Isolation and characterization of phenylethylamine and phenylethanolamine from human brain
Authors: Inwang E. E. , Mosnaim A. D. , Sabelli H. C. 
Published: October 2006

The Presence of endogenous 2‐phenylethylamine in mammalian tissues has long been suspected, in view of the fact that L‐phenylanine, a substrate for L‐aromatic amino acid decarboxylase (Lovenberg, Weissbach and Udenfriend, 1962), is found in substantial amounts in many neural and non‐neural tissues. It has been difficult to demonstrate the presence of phenylethylamine in tissues of untreated animals because this amine is an excellent substrate for monoamine oxidase (Mantegazza and Riva, 1963). Using paper chromatography and electrophoresis, Nakajima, Kakimoto and Sano (1964) tentatively identified phenylethylamine in many organs of animals pretreated with monoamine oxidase inhibitors. Phenylethylamine exerts, in animals pretreated with such inhibitors, behavioural stimulant effects similar to those induced by amphetamine (Mantegazza and Riva, 1963). These effects may in part be attributable to catecholamine release (Fuxe, Grobecker and Jonsson, 1967) and partly to a direct effect exerted by phenylethylamine itself (Fischer, Ludmer and Sabelli, 1967; Giardina, Pedemonte and Sabelli, 1972). The brain content of phenylethylamine in mice (Mosnaim and Sabelli, 1971), rabbits (Sabelli, Giardina, Mosnaim and Inwang, 1972) and rats (Fischer, Spatz, Heller and Reggiani, 1972) is increased by antidepressive treatments (imipramine, monoamine oxidase inhibitors, electroshock) and reduced by reserpine. The urinary excretion of phenylethylamine is decreased in depressed patients (Fischer, Heller and Miró, 1968; Boulton and Milward, 1971; Inwang, Sugerman, Mosnaim and Sabelli, 1972; Fischeret al., 1972).However, the presence of phenylethylamine in brain has not yet been conclusively demonstrated because the analytical procedures used in the above‐mentioned investigations were not sufficiently specific. In the present study we isolated and identified, by a number of analytical procedures, phenylethylamine and its metabolite 2‐hydroxy‐2‐phenylethylamine (phenylethanolamine) from human brain. Molinoff, Landsberg and Axelrod (1969) have shown by enzymatic methods the formation of phenylethanolamine following the administration of phenylethylamine.
ISOLATION AND CHARACTERIZATION OF AN ORGAN SPECIFIC RIBONUCLEOPROTEIN FROM GOAT BRAIN
Authors: Sharma N. C. , Talwar G. P. 
Published: October 2006

AbstractAn organ specific protein (NP) has been isolated from the goat brain by salt fractionation and preparative polyacrylamide gel electrophoresis. The antiserum against this protein gave immunological cross reaction with the brain extracts of a wide variety of animals but did not react with extracts of liver, lung, kidney, spleen, heart and blood. Similar proteins have also been found to be present in monkey brain and human astrocytomas in culture. Evidence is presented to show that it is a ribonucleoprotein. This is based on the following observations: (1) its absorption characteristics before and after RNase treatment, (2) chemical analysis showing the presence of ribose, purines and pyrimidines, (3) incorporation of radioactive uridine and lysine in monkey brain and in human astrocytomas in culture into a protein band having electrophoretic mobility and immunological characteristics analogous to NP protein.The molecular weight of the NP protein has been found to be 25,120 Daltons, while the residual moiety after treatment with RNase has a molecular weight of 19,060. The RNA content of NP protein in four separate preparations was 20.65% (±0.55 S.D.) as determined by the orcinol colour reaction and 23.85% (± 0.88 S.D.) gauged by the ratio of extinctions at 260 and 280 nm. The base composition of RNA has also been determined. The nature of association of the RNA moiety with the protein is not known. The two are, however, not dissociable by SDS and high pH excluding the possibility of aminoacyl linkage and nonspecific adsorption.
PLASMA AND BRAIN TRYPTOPHAN CHANGES IN EXPERIMENTAL ACUTE HEPATIC FAILURE
Authors: Curzon G. , Kantamanem B. D. , Winch J. , Rojas‐Bueno A. , Murray‐Lyon I. M. , Williams R. 
Published: October 2006

AbstractAn experimental model for acute hepatic failure in man was obtained in pigs by hepatic devascularization. After operation, liver function was grossly impaired, movements became inco‐ordinated and coma ensued. Most animals died 5½–8½ h after operation. Plasma unesteritied fatty acid and free (but not total) tryptophan concentrations rose markedly after operation and correlated significantly with each other. Brain tryptophan concentration increased and correlated significantly with plasma free tryptophan concentration. Increased tryptophan was found in the four brain regions studied (hypothalamus, thalamus, caudate and cortex) and was associated with raised 5‐hydroxytryptamine turnover as indicated by raised 5‐hydroxyindolylacetic acid concentration. Results are discussed in relation to altered tryptophan metabolism in human hepatic coma and to investigations of the influence of plasma unesterified fatty acid and free tryptophan changes on brain tryptophan metabolism in the rat.
Effect of intraventricular injection of 5,7‐dihydroxytryptamine on regional tryptophan hydroxylase of rat brain
Authors: Baumgarten H. G. , Victor S. J. , Lovenberg W. 
Published: October 2006

Abstract5,6‐DIHYDROXYTRYPTAMINE has been shown to cause selective degeneration of serotonergic neurons in the central nervous sytem (BAUMGARTEN, LACHENMAYER and SCHLOSSBERGER, 1972b). This degeneration is accompanied by depletion of serotonin (BAUMGARTEN et al., 1971; 1972a) and loss of tryptophan hydroxylase activity (VICTOR, BAUMGARTEN and LOVENBERG, 1973) in certain regions of the brain. In the current experiments, the effect of 5,7‐dihydroxytryptamine (another dihydroxylated tryptamine derivative) on tryptophan hydroxylase activity has been examined. Since tryptophan hydroxylase is the rate‐limiting enzyme in serotonin biosynthesis and has a similar distribution to that of serotonin in the brain, it is used as a biochemical marker of serotonergic neurons, Recent experiments also indicate that 5,7‐dihydroxytryptamine causes morphological damage to serotonergic neurons of the central nervous system (BAUMGARTEN and LACHENMAYER, 1972).
PARTIAL PURIFICATION AND PROPERTIES OF CHOLINE KINASE (EC 2.7.1.32) FROM RABBIT BRAIN: MEASUREMENT OF ACETYLCHOLINE
Authors: Haubrich D. R. 
Published: October 2006

AbstractCholine kinase (EC 2.7.1.32; ATP: choline phosphotransferase) was purified 200‐fold from an extract of acetone powder of rabbit brain by a combination of acid precipitation, ammonium sulphate precipitation, DEAE cellulose chromatography, and ultrafiltration. Maximal activity of 243 nmol of phosphorylcholine synthesized. min−1 mg−l of protein occurred at pH 9.5–10.0 in the presence of 10 mm MgS04, 10 mm choline and 0.005% (w/v) bovine serum albumin. 2‐Aminoethanol, 2‐methylaminoethanol, and 2‐dimethylaminoethanol were also phosphorlyated by the enzyme preparation. The enzyme quantitatively converted low concentrations of choline (2.5–50 μm) to phosphorylcholine [32P] in the presence of ATP [y32P], and may, therefore, be used to measure small amounts of choline acetylcholine. There were two Km values for choline at pH 9.5; 32 μm and 0.31 mm. At pH 7.4, the higher Km was not observed and enzyme activity was maximal with 0.1 mm choline. The Km for ATP was 1.1 mm. Enzyme activity was inhibited by ATP (20 mm), AMP, ADP, cytidine diphosphocholine (1 or 10 mm), and activated by choline esters (1.0 mm), NaCl or KCl(200 mm).