bluuebunny/crossref_metadata_2025_split huggingface dataset:
PREPARATION OF DNA AND FOUR DIFFERENT RNA SPECIES FROM RAT BRAIN. A NEW RNA FRACTION AND A NEW CHARACTERISTIC OF THE VARIOUS RNAs1
Authors: Oesterle W. , Kanig K. , Büchel W. , Nickel A.‐K. 
Published: October 2006

Abstract—A new modification is described for the fractionation of nucleic acids from brain. The cold phenol method followed by a hot extraction was combined with ‘salt‐precipitation’ and chromatography on Sephadex and Agarose gels. The method enables the isolation of five highly purified fractions in large amounts: DNA; high molecular weight salt‐soluble RNA, a hitherto undescribed fraction; rRNA; residual RNA (mRNA) and sRNA. All fractions showed, after 9 h in vivo incubation with 32P, different specific radioactivities and/or characteristic base compositions. The single mononucleotides of each RNA fraction differed markedly in their 32P‐labelling rate. This was found to be a new characteristic, for these differences were in no way similar in the various RNAs, but specific and constant for each fraction. An assay of base composition only by 32P‐labelling was therefore not possible.
SULPHATE METABOLISM IN ACUTE EAE1 RATS USING ISOLATED BRAIN PERFUSION TECHNIQUE
Authors: Vasan N. S. , Abraham J. , Bachhawat B. K. 
Published: October 2006

Abstract—Metabolism of glycolipids and glycosaminoglycans were studied in rats in the acute stage of experimental allergic encephalomyelitis (EAE) using isolated brain perfusion technique. It was observed that there was a significant decrease in the concentration of cerebroside, sulphatide and GAG (hyaluronic acid and low sulphated GAG) when compared to normal and pairfed control rats. The radioactive sulphate incorporation into the cerebroside sulphate and sulphated GAG was significantly higher in the case of rats in the acute stage of EAE than the normal and pairfed control rats.
THE UPTAKE AND SUBCELLULAR DISTRIBUTION OF AROMATIC AMINES IN THE BRAIN OF THE RAT1
Authors: Baldessarini R. J. , Vogt Marcella 
Published: October 2006

Abstract—The hydroxylated phenylethylamines p‐tyramine, m‐tyramine, octopamine, metaraminol and norepinephrine were accumulated by homogenates of rat brain much more vigorously than β‐phenethylamine or amphetamine. The affinity concentrations (Km) for initial (5‐min) uptake by homogenates of whole brain were 0.5, 3 and 6 μM for DL‐norepine‐phrine, p‐tyramine and DL‐octopamine, respectively. The uptake of these three hydroxylated compounds was much more vigorous in striatal tissue than in cortical tissue, and in both tissues the rate of uptake decreased in the sequence: norepinephrine > tyramine > octopamine. The uptake of these three substances was inhibited by reduced temperature, by lack of glucose, by CN‐ and DNP, and by desmethylimipramine, cocaine and ouabain. The uptake of norepinephrine and octopamine appeared to require Na+. Pretreatment of rats with reserpine or 6‐hydroxydopamine decreased the ability of brain to take up norepinephrine or octopamine. Previously accumulated labelled phenylethylamines migrated in sucrose density gradients with a peak of radioactivity corresponding to an equilibrium position of catecholamine‐containing nerve endings. The magnitude of the retention of [3H]amine in this synaptosornal peak decreased in the order: norepinephrine > octopamine > tyramine. The accumulated amines were released by sonic, osmotic and thermal stresses which disrupt neuronal membranes. The presence of a β‐hydroxyl group appeared to protect amines from destruction by monoamine oxidase, presumably by virtue of uptake in presynaptic storage vesicles. During superfusion, tyramine and metaraminol appeared to displace [3H]norepinephrine from binding sites in brain slices.
A MICRO‐SCALE PROCEDURE FOR THE PREPARATION OF SUBCELLULAR FRACTIONS FROM INDIVIDUAL AUTONOMIC GANGLIA
Authors: Giacobini E , Hökfelt T , Kerpel‐Fronius S , Koslow S. H , Mitchard M , Noré B 
Published: October 2006

Abstract— A microscale modification for the preparation of subcellular fractions employing milligram and submilligram amounts of neuronal tissue (brain nuclei and autonomic ganglia) is described.Electron microscope characterization and enzymic studies were carried out on the six subcellular fractions of sympathetic ganglia of cat thus prepared.The synaptosomal preparations obtained from individual ganglia were poorer in their nerve ending content than those obtained from brain by previous investigators. The highest RSA for AChE was found in layer L2 which was rich in membranes and vesicle components. ChAc activity was also highly concentrated in layers L2 and L3 (membranes, nerve ending‐like particles, mitochondria and ‘ghosts’). MAO activity was particularly high in the layers L4 and L5 which contained a large number of mitochondria. Layer L1 (membrane fragments) and particularly layer L6 which contained mainly collagen fibres, were low in activity of all three enzymes.After preganglionic denervation, both ChAc and AChE activities were significantly reduced in the purest nerve ending fraction, L3 while MAO activity was practically unchanged.
THE MASS DISTRIBUTION OF THE PHOSPHATIDYLCHOLINES IN SUBCELLULAR FRACTIONS OF RAT BRAIN1
Authors: O'Brien J. F. , Geison R. L. 
Published: October 2006

AbstractWhole brains from 20‐22‐day‐old rats were separated into the 15,000 g supernatant, myelin, nerve ending and mitochondrial fractions. Gas chromatography of the trimethylsilyl derivatives of 1,2‐diglycerides obtained by hydrolysis with phospholipase C of the phosphatidylcholine from each fraction showed marked differences of carbon number distribution (i.e. the sum of the carbon atoms in the two fatty acids of the diglyceride) among the different membranous fractions. Further characterization of each diglyceride was obtained by preparative gas chromatography of the diglyceride‐trimethylsilyl ethers and determination of the acyl moieties after collection, methanolysis and gas chromatography.The results indicate that at least three distinct populations of phosphatidylcholine exist in the brain. Nerve endings and the 15,000 g supernatant fraction exhibit a very similar diglyceride pattern with dipalmitoylglycerophosphorylcholine representing over 30 per cent of the species present. Myelin has a unique phosphatidylcholine composition with much less polyenoic species in the 36 and 38 carbon number peaks. Mitochondria contain phosphatidylcholines with relatively more long‐chain polyunsaturated fatty acids. TLC of the phosphatidylcholines yielded partial separation into two spots, which differed in distribution of fatty acids. The faster migrating spot contained most of the polyenoic acids, whereas the slower migrating spot contained most of the palmitic, stearic and oleic acids.
PARTICULATE AND SOLUBILIZED FUCOSYL TRANSFERASES FROM MOUSE BRAIN
Authors: Zatz M. , Barondes S. H. 
Published: October 2006

AbstractThe transfer of [14C]fucose from GDP‐[U‐14C]fucose to endogenous and exogenous acceptors by particulate and solubilized preparations from mouse brain is described. Suspensions of brain microsomes incorporated [14C]fucose into a heterogenous group of glycoprotein products, which have a distribution on gel electrophoresis similar to those synthesized in vivo. Fucosyl transferase, extracted from brain microsomes by Triton X‐100, transferred [14C]fucose from GDP‐[U‐14C]fucose to terminal galactose residues exposed by mild acid hydrolysis of porcine plasma glycoprotein. Comparison of the specific activities of the solubilized fucosyl transferase from a number of organs showed that, in the presence of the exogenous acceptor which was used, the transferase of brain was more active than the transferases from all other organs tested, with the exception of kidney. Examination of subcellular fractions of brain, with endogenous and exogenous acceptors, showed that activity was limited to fractions containing microsomal membranes, whereas synaptosomal and other fractions were virtually inactive.
REGIONAL CHANGES IN BRAIN CATECHOLAMINES AFTER PROTON IRRADIATION OF THE STRIATE CORTEX IN THE SQUIRREL MONKEY
Authors: Hsu L. L. , Samorajski T. , Ordy J. M. , Bose H. , Curtis H. J. 
Published: October 2006

AbstractTo establish possible functional relationships between anatomically distinct cortical centres in primates, we compared changes in visual acuity, nucleic acids, protein, enzymes and catecholamines in cortical and subcortical areas six months after 10,000 and 20,000 rd of proton irradiation of striate area 17 of the visual cortex of the squirrel monkey. Minimum separable acuity was reduced from 1 minute of arc in controls to 4 minutes in the 20,000‐rd group. DNA, RNA and protein contents were not altered, but the activity of acetylcholinesterase was increased significantly in area 17. A decrease of norepinephrine occurred in the hypothalamus, hippocampus, caudate nucleus, putamen and brain stem of the irradiated brains. Since no ultrastructural basis has been found to account for these changes, we assume that a sustained chemical change occurred at the irradiated site and that the effect was transmitted to non‐irradiated regions of the brain.
THE BINDING OF BOTULINUM TOXIN TO MEMBRANE LIPIDS: PHOSPHOLIPIDS AND PROTEOLIPID
Authors: Simpson L. L. , Rapport M. M. 
Published: October 2006

AbstractA number of phospholipids known to be constituents of nerve endings were tested for their ability to inactivate botulinum toxin. Substances tested included phosphatidylcholine, phosphatidalcholine, phosphatidylethanolamine, phosphatidalethanolamine, β‐acyl lysolecithin, sphingomyelin, phosphatidylserine, phosphatidic acid, phosphatidylinositol and cardiolipin. Proteolipid from bovine white matter was also tested. Neutral phospholipids potentiated the toxicity in vivo of botulinum toxin, but they had no effect on the toxicity in vitro. Some, but not all, acidic phospholipids caused loss of toxicity of botulinum toxin in solutions at low pH both in vivo and in vitro. However, none of these substances when incubated with toxin under physiological conditions of temperature, pH and ionic strength, caused loss of toxin potency. The data suggest that none of these phospholipids is likely to be a toxin receptor.
EXPERIMENTAL ALCOHOLISM IN RATS. EFFECT OF ACUTE ETHANOL INTOXICATION ON THE IN VITRO INCORPORATION OF [3H]LEUCINE INTO NEURONAL AND GLIAL PROTEINS1
Authors: Jarlstedt J. , Hamberger A. 
Published: October 2006

Abstract— Ethanol administered in vivo or in vitro during incubation of brain slices was studied with respect to its effect on brain protein synthesis.In the in vivo series the rats were given a single intraperitoneal injection of ethanol 3 h before death. Slices of cerebral cortex and liver were incubated in isotonic saline media containing [3H]leucine. Amounts of free and protein‐bound radioactivity were determined. Subcellular fractions and fractions enriched in neuronal perikarya and in glial cells were prepared from cortical slices subsequent to incubation, and the specific radioactivity determined for each cell type.The incorporation of [3H]leucine into brain proteins was inhibited while incorporation into liver proteins was stimulated in ethanol‐treated rats. The levels of TCA‐soluble radio‐activity, however, did not differ between the ethanol group and the controls. In the fractionated material from cerebral cortex, the specific radioactivity in the neuronal fraction was unaffected by ethanol, while the radioactivity in the glial fraction was significantly depressed. In vitro administration of ethanol induced a non‐linear response in both brain and liver, with depression of leucine incorporation into proteins of cerebral cortex at all concentrations used. When brain slices were exposed to ethanol in vitro, in concentrations corresponding to the in vivo experiments, a similar reduction of the leucine incorporation into the glial fraction was obtained. Incorporation of leucine into subcellular fractions from whole brain cortex was also investigated. The specific sensitivity of the glial fraction to ethanol is discussed in relation to the involvement of the different cell types with transport processes in the brain.
THE ACYLATION OF L‐GLYCEROL‐3‐PHOSPHATE MICROSOMES FROM RAT BRAIN: EFFECTS ARISING FROM THE PROPERTIES OF THE REACTION MEDIUM1,2
Authors: Kuwahara S. S. 
Published: October 2006

Abstract— The velocity of the reaction catalysed by acyl‐CoA: l‐giycerol‐3‐phosphate acyltransferase (EC 2.3.1.15) of microsomes from rat brain was affected by the nature of the buffering agent, the ionic strength and the sucrose concentration of the reaction medium. The enzyme was inhibited by buffers based on trimethyl‐pyridine, diethyl barbituric acid, and boric acid. Buffers based on N‐ethyl morpholine, potassium phosphate, sodium arsenate, imidazole, tris and triethanolamine were not inhibitory. Dithiothreitol protected the enzyme and produced maximal activity at levels in the reaction medium between 0.2 and 2.8 mM.Optimum ionic strength was determined by varying the concentration of a potassium phosphate buffer and in this medium the optimum ionic strength was about 0.2 M. In other studies with sodium formate, potassium acetate and other salts there was a broad plateau of activity in a range about 0.2 M. A study of pH vs. activity with two different buffering agents at constant ionic strength showed a broad maximum of activity from pH 7.2 to pH 7.8. The velocity of the reaction could be further increased by the inclusion of 0.25 M‐sucrose in the reaction medium in the presence of 0.2 M salts. The sucrose effect produced maximum velocities at sucrose concentrations ranging from 0.2 to 0.6 M. The studies reported here indicate that the activity of the enzyme is dependent upon the state of hydration of the microsomal membranes and in part on the ability of the enzyme or membrane to cope with large micelles of S‐palmityl‐CoA.
Differences in the apparent molecular weight of soluble and mitochondrial hexokinases of rat brain
Authors: Teichgräber P. , Biesold D. 
Published: October 2006

In Brain tissue only 10–20 percent of the total hexokinase activity (EC 2.7.1.1) is present in the cytoplasm whereas the particulate activity is associated with mitochondria (Bachelard, 1967; Teich‐graber, Biesold and Pigarewa, in press). Either small (Wilson, 1968) or insignificant kinetic differences (Thompson and Bachelard, 1970; Bigl, Müller and Biesold, 1971) between soluble and particulate enzyme activity have recently been reported. Though the DEAE cellulose column chromatography patterns of both hexokinases were reported to be similar (Thompson and Bachelard, 1970; Bigl, Müller and Biesold, 1971), differences were found between soluble and mitochondrial hexokinase after gel electrophoresis separation (Bachelard, 1967; Bigl, Muller and Biesold, 1971). Recently it has been shown in this laboratory that Triton X‐100 also enhances the hexokinase activity of the cytoplasm as has already been demonstrated for the mitochondrial form (in preparation).The purpose of the experiments described here was to elucidate whether the soluble cytoplasmic hexokinase differs from the mitochondrial‐bound hexokinase in respect to its apparent molecular weight. To diminish the occurrence of experimental artefacts, different extraction procedures were employed. Furthermore, the effect of Triton X‐100 on the molecular weight was investigated in an attempt to reveal an explanation for the increase in enzymic activity after incubation of hexokinase with this detergent.
DISPOSITION OF FUCOSE IN BRAIN1
Authors: Margolis Renée K. , Margolis R. U. 
Published: October 2006

Abstract— Labelled fucose administered to rats in vivo was rapidly incorporated into brain glycoproteins, but not into any other brain constituents, including glycolipids and acid mucopolysaccharides. Maximum incorporation of tritium‐labelled fucose into brain glyco‐proteins occurred 3–6 h after intraperitoneal injection in young or adult rats, and the half‐time for the turnover of glycoprotein‐fucose in young rats was approximately 2 weeks.Within 3 h after the administration of either [1‐3H]fucose or fucose generally labelled with tritium, 75 per cent of the total acid‐soluble radioactivity in plasma and brain was found to be volatile, and by 24 h after injection more than 90 per cent of the acid‐soluble radioactivity was volatile. The tritium in labelled fiicose appears to undergo arapid exchange reaction with hydrogen atoms in body water, although the tritium in fucose glycosidically‐ linked to glycoproteins is biologically stable. The rapid disappearance of labelled free fucose from the plasma and tissues of the rat precludes the possibility of any significant degree of reutilization of labelled precursor, and provides support for other data indicating that the turnover of fucose in brain glycoproteins is relatively slow in comparison to that of hexosamine and sialic acid.Activities of α‐L‐fucosidase in rat brain, with pH optima at 40 and 6.0, had essentially the same Km (4 × 10−4 M and 3.2 × 10−4 M, respectively) with p‐nitrophenyl‐α‐L‐fucopyranoside as substrate. Activities of both were competitively inhibited by L‐fucose. However, the Kt measured at pH 4 (1.9 × 10−2) was almost ten times greater than that measured at pH 6 (1.5 × 10−4).
AN INHERITED DEFICIENCY IN NORADRENALINE BIOSYNTHESIS IN THE BRINDLED MOUSE
Authors: Hunt D. M. , Johnson D. R. 
Published: October 2006

Abstract—A reduction in central and peripheral synthesis of noradrenaline has been demonstrated in mice hemizygous for the X‐linked brindled (Mobr) mutant in the mouse. The results are consistent with defective hydroxylation of dopamine to NA, arising either as a result of a primary genetic defect in the enzyme dopamine‐β‐hydroxylase or from the presence of a highly specific inhibitor of this enzyme in mutant mice. Associated with this deficiency of noradrenaline are an increase in the activity of tyrosine hydroxylase in the central nervous system and an increase in the active uptake of tyrosine (and other amino acids sharing a common uptake mechanism with tyrosine) across the blood‐brain barrier.
CHARACTERISTICS AND PRODUCTS OF A CELL‐FREE POLYPEPTIDE SYNTHESIZING SYSTEM FROM NEONATAL AND ADULT MOUSE BRAIN
Authors: Gilbert B. E. , Grove Barbara K. , Johnson T. C. 
Published: October 2006

Abstract—The regulation of protein synthesis by ribosomes isolated from mouse brain tissue was studied using a cell‐free polyphenylalanine synthesizing system. Polypeptide synthesis was followed by assaying translocation and analysing the reaction products by BD‐cellulose chromatography. The brain ribosomal activity could be divided by these methods into two distinct steps : binding of aminoacyl‐tRNA to the ribosome and active translocation leading to subsequent polyphenylalanine synthesis. In comparison to initial binding of aminoacyl‐tRNA, translocation in the cell‐free system increased the incorporation of labelled phenylalanine by 10‐fold. An analysis of the reaction products clearly showed active ribosomal synthesis of oligophenylalanine from [3H]phe‐tRNA. Ribosomes isolated from neonatal brain tissue were 2–4 times as active as those obtained from adult brain tissue in polypeptide synthesis. In addition, polypeptides synthesized on the more active ribosomes from neonates tended to be of greater chain length than those from adult. Therefore, the maturation‐dependent decrease in ribosomal protein synthetic activity during neural development was shown to be directly associated with the ribosome particles.
THE REGIONAL DISTRIBUTION OF d‐GLYCERATE DEHYDROGENASE AND 3‐PHOSPHOGLYCERATE DEHYDROGENASE IN THE CAT CENTRAL NERVOUS SYSTEM: CORRELATION WITH GLYCINE LEVELS
Authors: Uhr M. L. , Sneddon M. K. 
Published: October 2006

AbstractThe activities of d‐glycerate dehydrogenase, 3‐phosphoglycerate dehydrogenase and lactate dehydrogenase have been measured in high‐speed supernatant fractions from different regions of the cat CNS. Only d‐glycerate dehydrogenase showed any significant regional variation in levels of activity, and this regional distribution correlated well with the regional distribution of glycine. In view of the previous finding that glycine inhibits d‐glycerate dehydrogenase of rat cortex in a non‐competitive manner suggesting endproduct inhibition (Uhr and Sneddon, 1971) this correlation is considered additional evidence to suggest that d‐glycerate may be an important source of glycine in the CNS.
THE APPARENT TURNOVER OF MITOCHONDRIA, RIBO‐SOMES AND sRNA OF THE BRAIN IN YOUNG ADULT AND AGED RATS1
Authors: Menzies R. A. , Gold P. H. 
Published: October 2006

Abstract—[14C] orotic acid and [3H]l‐leucine were injected intraperitoneally into two groups of rats, aged 12 and 24 months, respectively. The apparent turnover of RNA and protein from several subcellular fractions was assessed by following the loss of label from these fractions with time. The curves for apparent turnover of all protein fractions from mitochondria were single exponential curves. Total mitochondrial protein from younger animals had a half‐life of 26.8 days. Two protein subfractions, protein insoluble in cold perchloric acid and chloroform‐methanol (residual protein) and protein soluble in chloroform‐methanol (C–M protein) had similar half‐lives: 26.3 and 26.1 days, respectively. For the older animals the half‐lives were 23.5 days for total protein, 17.4 for residual protein and 30.4 for C–M protein. The difference between the two protein subfractions from mitochondria of the older animals suggests an age‐associated deviation from the synchrony of synthesis and degration of proteins in this organelle.Further deviation from the unit concept of mitochondrial turnover was seen in the apparent turnover of mitochondrial RNA. Mitochondrial RNA had half‐lives of 10.0 and 11.6 days for older and younger animals, respectively, with no significant difference between the groups. No age‐associated difference was observed in the apparent turnover of sRNA. This fraction exhibited a double exponential turnover pattern; the first component in both cases had a half‐life of about 5–8 days and the second component 13–16 days. Ribosomal RNA and protein from both older and younger animals exhibited multiexponential kinetics but both components, RNA and protein, within each age group appeared to turn over synchronously. Average values for apparent turnover of total ribosomes (RNA and protein) were 18.2 days for the older animals and 7.4 days for the younger animals. The age‐associated difference was highly significant P < (0.001).
ACCUMULATION OF GLUTAMIC ACID IN THE ARCUATE NUCLEUS OF THE HYPOTHALAMUS OF THE INFANT MOUSE FOLLOWING SUBCUTANEOUS ADMINISTRATION OF MONOSODIUM GLUTAMATE1
Authors: Perez V. J. , Olney J. W. 
Published: October 2006

Abstract—Monosodium l‐glutamate was injected subcutaneously into 4‐day‐old mice at a dose of 2 mg/g body wt. The infants were killed at sequential intervals after injection, the brains were frozen, and samples of the arcuate nucleus (NA), ventromedial hypothalamus (VMH) and lateral thalamus (LT) were micro‐dissected from lyophilized sections for glutamate assay. Blood glutamate levels were also determined for comparison with brain levels of glutamate at corresponding post‐injection intervals. Glutamate levels in the NA steadily increased to reach a peak value of 110.9 mmol/kg dry wt. at 3 h following injection, whereas the highest levels reached in the VMH or LT were about 41.7 mmol/kg dry wt. Return to control values of about 25 mmol/kg dry wt. occurred gradually over a period of 12–15 h in all three brain regions. Blood glutamate concentrations peaked rapidly, reaching a maximum of 40 mm within 15 min but returned precipitously to near‐baseline values (below 1 mm) in the 1–3 h interval after injection. We discuss possible mechanisms to account for the transient marked accumulation of subcutaneously administered glutamate in the NA and how this might relate to the selective destruction of arcuate neurons which occurs simultaneously.