bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic diversity of captive binturongs (Arctictis binturong, Viverridae, Carnivora): implications for conservation
Authors: Cosson L. , Grassman L. L. , Zubaid A. , Vellayan S. , Tillier A. , Veron G. 
Published: September 2006

AbstractThe binturong Arctictis binturong is a threatened carnivore (Mammalia) that ranges throughout the forests of South‐east Asia. This study evaluates the genetic diversity of captive binturong populations in European zoos and attempts to assess their geographic origin. We sequenced the hypervariable region 1 of the mitochondrial control region of 56 binturongs, among which 20 had a known geographic origin. We showed that at least two distinct geographic clades exist and were able to assess the geographic clade to which captive individuals belong. Moreover, a low genetic diversity was observed among the captive population of European zoos. Although our results are preliminary, zoo managers should consider the evolutionary significant units identified by this study, and which correspond to recognized sub‐species, when planning binturong reproduction programs.
Morphology, echolocation and foraging behaviour in two sympatric sibling species of bat (Tylonycteris pachypus and Tylonycteris robustula) (Chiroptera: Vespertilionidae)
Authors: Zhang L. , Liang B. , Parsons S. , Wei L. , Zhang S. 
Published: September 2006

AbstractWe studied the wing morphology, echolocation calls, foraging behaviour and flight speed of Tylonycteris pachypus and Tylonycteris robustula in Longzhou County, South China during the summer (June–August) of 2005. The wingspan, wing loading and aspect ratio of the two species were relatively low, and those of T. pachypus were lower compared with T. robustula. The echolocation calls of T. pachypus and T. robustula consist of a broadband frequency modulated (FM) sweep followed by a short narrowband FM sweep. The dominant frequency of calls of T. pachypus was 65.1 kHz, whereas that of T. robustula was 57.7 kHz. The call frequencies (including highest frequency of the call, lowest frequency of the call and frequency of the call that contained most energy) of T. pachypus were higher than those of T. robustula, and the pulse duration of the former was longer than that of the latter. The inter‐pulse interval and bandwidth of the calls were not significantly different between the two species. Tylonycteris pachypus foraged in more complex environments than T. robustula, although the two species were both netted in edge habitats (around trees or houses), along pathways and in the tops of trees. Tylonycteris pachypus flew slower (straight level flight speed, 4.3 m s−1) than T. robustula (straight level flight speed, 4.8 m s−1). We discuss the relationship between wing morphology, echolocation calls, foraging behaviour and flight speed, and demonstrate resource partitioning between these two species in terms of morphological and behavioural factors.
Large‐scale seasonal variation in the prevalence and severity of chytridiomycosis
Authors: Kriger K. M. , Hero J.‐M. 
Published: September 2006

AbstractThe chytrid fungus Batrachochytrium dendrobatidis has been implicated as the causative agent of mass mortalities, population declines and the extinctions of amphibian species worldwide. Although several studies have shown that the prevalence of chytridiomycosis (the disease caused by the fungus) increases in cooler months, the magnitude and timing of these seasonal fluctuations have yet to be accurately quantified. We conducted disease sampling in a single population of stony creek frogs Litoria wilcoxii on 13 occasions over a 21‐month period and used quantitative real‐time polymerase chain reaction to detect and quantify the number of B. dendrobatidis zoospores present on samples. Disease prevalence varied significantly across sampling sessions, peaking at 58.3% (in early spring) and dropping to as low as 0% on two occasions (late summer and early autumn). There was a significant negative relationship between disease prevalence and mean air temperature in the 30 days prior to sampling. These large‐scale seasonal fluctuations in chytridiomycosis levels will strongly influence conservation programs and amphibian disease research.
THE CONCENTRATIONS OF FREE AMINO ACIDS AND OTHER ELECTROLYTES IN CEREBROSPINAL FLUID, IN VIVO DIALYSATE OF BRAIN, AND BLOOD PLASMA OF THE DOG*
Authors: BITO L. , Davson H. , Levin E. , Murray M. , Snider N. 
Published: October 2006

SUMMARYThe concentrations of free amino acids in plasma, CSF and in vivo dialysates of peripheral blood (neck sac fluid) and central nervous tissue (brain sac fluid) from each of five dogs (neck sac fluid from four of five dogs) were determined by ion‐exchange chromatography. Dialysates were obtained by implanting small dialysis sacs filled with a dextran‐saline solution into the subcutaneous tissue of the neck or the parenchyma of the brain at least 10 weeks before sample collection.The mean plasma concentration of most amino acids was within the range of values reported in the literature for human or dog plasma. The concentrations of most amino acids were higher in the neck sac fluid than in plasma; this discrepancy, however, was, for the most part, small and could most likely be accounted for by falling plasma free amino acid levels prior to sample taking. Previous conclusions that the CSF concentrations of most amino acids are lower than plasma concentrations are confirmed, although the present work indicates that there may be considerable individual variation in the CSF/plasma distribution ratio with respect to most amino acids.In the brain sac fluid the concentration of nearly every amino acid was consistently higher than that in CSF and lower than that in the neck sac fluid. The potassium concentration in the brain sac fluid was significantly higher than, and the total osmolality significantly lower than, those in the neck sac fluid. On the assumption that the brain sac fluid represents a dialysate of the brain extracellular fluid, these results contradict recent findings (Bito and Davson, 1965; 1966) indicating that the potassium concentration of the cortex extracellular fluid is lower than that of ventricular or cisterna magna CSF and certainly lower than that of plasma. Because of this and on the basis of consideration of the reaction of the brain to a foreign body, the possibility that the implanted brain sac lay on the‘blood side’of the bloodbrain barrier was suggested. Some implications of this possibility are discussed.
THE FREE AMINO ACIDS OF HUMAN SPINAL FLUID DETERMINED BY ION EXCHANGE CHROMATOGRAPHY
Authors: Dickinson Johanne C. , Hamilton Paul B. 
Published: October 2006

SUMMARY(1) The free amino acids in human CSF from eighteen subjects have been determined. The analyses were performed on 0‐75 ml of CSF by an ion exchange chromatographic method which is capable of detection to the 10−10 mole level.(2) The amino acids always found in readily detectable amounts were: taurine, threonine, serine, glutamine, glutamic acid, citrulline, glycine, alanine, α‐NH2‐n‐ butyric acid, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, ethanolamine, ornithine, lysine, histidine and arginine. Urea was present. Aspartic acid and cystine, though always present, occurred in small or trace amounts. Proline was found in four cases and tryptophan in thirteen cases. In addition, twelve unknown peaks were nearly always evident in every chromatogram.(3) Filtrates 10 times more concentrated than those used regularly were prepared from pooled CSF and analysed. These analyses clearly confirmed the presence of those amino acids which were normally in very low concentration and they also served to distinguish the twelve unknown compounds from confusion with baseline artifacts.(4) The distribution of free amino acids in CSF was different from their distribution in blood plasma.(5) Despite a variety of neurological conditions and a wide age span few marked deviations were found in any of the amino acid concentrations.
HORMONAL CONTROL OF GLYCEROLPHOSPHATE DEHYDROGENASE IN THE RAT BRAIN1
Authors: de Vellis Jean , Inglish Diane 
Published: October 2006

Abstract—Following hypophysectomy or adrenalectomy, glycerolphosphate dehydrogenase (GPDH) (EC 1.1.1.8) activity decreased exponentially in the cerebral hemispheres and brain stem of adult male rats. The latter region was more affected than the former. Malate dehydrogenase (EC 1.1.1.40), isocitrate dehydrogenase (EC 1.1.1.42), lactate dehydrogenase (EC 1.1.1.27) and mitochondrial glycerolphosphate dehydrogenase (EC 1.1.95.5) activities remained unchanged. Injection of adrenocorticotrophic hormone or cortisol in hypophysectomized rats or cortisol in adrenalectomized rats restored GPDH activity. Thyroidectomy and gonadectomy had no effect on GPDH activity. Liver GPDH was not decreased by hypophysectomy or adrenalectomy. Muscle GPDH was diminished slightly by adrenalectomy and as much as brain GPDH by hypophysectomy. In young rats GPDH developmental increase in activity was inhibited by hypophysectomy. These results clearly show that brain GPDH activity is specifically regulated by cortisol (and probably closely related corticosteroids).
A TECHNIQUE FOR THE STUDY OF ACETYLCHOLINE TURNOVER IN MOUSE BRAIN IN VIVO
Authors: Schuberth J. , Sparf B. , Sundwall A. 
Published: October 2006

Abstract— —A method to measure the rate of acetylcholine turnover in mouse brain in vivo has been developed. It is based on the formation of labelled acetylcholine from intravenously injected labelled choline. The isotopic dilution of choline in the brain has been measured by assaying endogenous choline in the brain by an enzymatic method using tritium‐labelled acetyl‐CoA and purified choline acetyltransferase.The rate of acetylcholine turnover in the brain could be calculated at 50 n‐moles acetylcholine/g/min in conscious mice. In anaesthetized mice and in mice treated with oxotremorine, a decrease of acetylcholine turnover to about 10 n‐moles/g/min was found.
EFFECT OF γ‐AMINOBUTYRIC ACID ON BRAIN SEROTONIN AND CATECHOLAMINES
Authors: Yessaian N. H. , Armenian A. R. , Buniatian H. Ch. 
Published: October 2006

Abstract—Intraperitoneal injections of GABA (5 mg/kg) to rats lowered the level of norepinephrine in brain, heart and spleen but not suprarenals and raised that of serotonin in brain. Changes of these monoamines were most pronounced in the hypothalamic region after 20min. A reduction of hypothalamic norepinephrine was also observed 15min following the intracarotid administration of 0·5 mg/kg of GABA. In these experiments there was a concomitant increase in the level of free GABA in the anterior portion of the ventral hypothalamus. Brain dopamine level and 5‐hydroxytryptophan decarboxylase, dihydroxyphenylalanine decarboxylase and monoamine oxidase activities were not affected. The 20 per cent increase of endogenous GABA observed in the midbrain 30 min following the administration of amino‐oxyacetic acid was accompanied by a sharp fall in norepinephrine level (39 per cent) and an increase in serotonin (20 per cent).In in vitro studies 10–300 μg/ml of GABA were shown to release norepinephrine from cortical and hypothalamic slices, and to inhibit serotonin release without affecting 5‐hydroxytryptophan uptake and to have no effect on the release of dopamine from slices of the region of the corpus striatum nor on the activity of the enzymes mentioned.Subcellular studies showed that the particulate:supernatant ratio for norepinephrine was reduced from a control value of 2·04 to 1·75 and that of serotonin was raised from 2·8 to 3·5. Following pretreatment with iproniazid, GABA reduced the raised level of brain norepinephrine to a greater extent than reserpine but not as intensively as amphetamine.The results obtained suggest that these monoamines may be involved in the mechanisms underlying the action of GABA in brain and that the effect of GABA on brain monoamines may be of certain significance in synaptic events.
CHEMOSENSING: SELECTIVITY, SENSITIVITY AND ADDITIVE EFFECTS ON A STIMULANT‐INDUCED ACTIVITY OF OLFACTORY PREPARATIONS
Authors: Ash K. O. , Skogen J. D. 
Published: October 2006

Abstract—Stimulant‐induced changes in soluble preparations from rabbit olfactory epithelium were monitored by ultraviolet difference spectroscopy. A time‐dependent decrease of absorbance, maximum at 267 nm, was generated when specific stimulants were mixed with the olfactory preparations. Only seven of the 37 organic chemicals tested generated the absorbance change at 267 nm. The olfactory preparations exhibited a high degree of selectivity and sensitivity; measurable absorbance changes were observed when the active stimulant concentrations were 1 × 10−5m. The experimental results suggest a complex mechanism of conformational change for the initial stimulant‐induced molecular interactions in biological chemosensing.
PATTERN OF RNA SYNTHESIS IN RABBIT CORTEX DURING SLEEP
Authors: Vitale‐Neugebauer A. , Giuditta A. , Vitale B. , Giaquinto S. 
Published: October 2006

Abstract—The pattern of RNA biosynthesis in rabbit cerebral cortex was examined during periods of physiological sleep and wakefulness monitored with EEG techniques. The types of newly synthesized RNA were analysed by sedimentation on sucrose gradients. In experiments lasting 60 and 105 minutes the labelling ratio of RNA sedimenting in two regions of the gradient (28 S‐50 S50 S) increased with decreasing percentages of EEG synchronization. Analysis of the radioactivity distributions of five homogeneous experiments in terms of moments confirmed the dependence of the RNA synthetic pattern on the electric state of the cortex. The possible nature of the RNA species involved in this effect is discussed.
A STUDY OF THE NASCENT POLYPEPTIDES SYNTHESIZED ON THE FREE POLYRIBOSOMES OF RAT BRAIN IN VIVO1
Authors: Sellinger O. Z. , Ohlsson W. G. , Frankel A. J. , Azcurra J. M. , Petiet Patricia D. 
Published: October 2006

AbstractThe free polyribosomes of the cerebral cortex of the immature rat (12‐14 days old) were exposed to very low concentrations of trypsin at 0°C and for very brief periods of time and the conditions under which their breakdown to smaller aggregates occurs were determined. Trypsin also caused the release of nascent, radioactive polypeptides from polyribosomes prelabelled with [14C]amino acids in vivo. An examination of the kinetics of release of the nascent chains by trypsin revealed that it was dependent on the concentration of trypsin as well as on the duration of incubation in the presence of trypsin. The influence of the nature of the [14C]amino acid used as precursor of the nascent polypeptides and of the duration of the radioactive pulse in vivo was also determined. The radioactivity associated with polyribosomes as a result of the brief radioactive pulses administered (2 to 10 minutes) was incompletely removed even after the ribosomes were dissociated into subunits by EDTA. These findings suggest that the assembly of the cerebral ribosome in vivo must be a very rapid process, particularly in the immature animal.The nature of the nascent, radioactive polypeptides was studied by disc gel and high voltage electrophoresis and by thin‐layer and column chromatography. Evidence was obtained that a rather limited number of qualitatively different molecules resides on the polyribosomes at any given moment.
DYNAMIC CHARACTERISTICS OF THE ‘FUNCTIONAL COMPARTMENT’ OF DOPAMINE IN DOPAMINERGIC TERMINALS OF THE RAT STRIATUM
Authors: Javoy F. , Glowinski J. 
Published: October 2006

AbstractRats were injected with α‐methyl‐p‐tyrosine and the disappearance of dopamine in the striatum was examined as a function of time. Two main phases of dopamine decline were detected which probably correspond to the amine utilization in a ‘functional’ and a ‘main storage compartment’ in dopaminergic terminals. Similar observations were made when the turnover of dopamine had been previously accelerated by thioproperazine. In control rats the half‐lives of dopamine were about 9 and 120 min in the ‘functional’ and ‘main storage’ compartments respectively. The rate of dopamine synthesis was estimated to be not less than 13‐2 μg/g/h and the rate of dopamine utilization in the ‘functional compartment’ was calculated to be about four times that of the ‘main storage compartment'.
SOME FACTORS INFLUENCING BRAIN GLYCOGEN IN THE NEONATE CHICK
Authors: Edwards C. , Rogers K. J. 
Published: October 2006

Abstract—Studies of the brain glycogen concentration in the chick during the perinatal period showed that there was an increase immediately prior to hatching. This was followed by a pronounced decrease between 1 and 2 days after hatching. The decrease was most marked in the cerebellum. During ischaemia, the rate of glycogen depletion was greater in 1‐day‐old chicks than in 2‐ and 7‐day‐old birds. Brain glycogen concentration exhibited a circadian rhythm which was not closely related to changes in motor activity or body temperature. Exposure to a high environmental temperature (40°C) caused a depletion of glycogen, but exposure to a low temperature (2°C) had no effect. Four hours of hyperglycaemia resulted in a lowering of brain glycogen levels whereas hypoglycaemia was without effect.
BRAIN METABOLISM AT LOW TEMPERATURES
Authors: Heckers H. , Gercken G. 
Published: October 2006

Abstract— Levels of ATP, ADP, phosphocreatine, glycogen, glucose, lactic acid and inorganic phosphate in the rabbit brain were determined after cerebral hypothermia to 24, 22, 20, 18 and 16°C brain temperature. Hypothermia was induced by isolated head perfusion by means of an extracorporeal device including a donor animal of the same species. In two experiments brains were cooled to 24 and 16°C, followed by rewarming to nearly normothermic values before brain biopsy was performed. In all experiments the electrical activity of the cerebral cortex was recorded intermittently.No metabolic disturbances could be observed in 25 out of a total number of 26 experiments. Only one experiment showed a marked decrease in cerebral content of high‐energy phosphates, glycogen and glucose and a corresponding increase of lactic acid and inorganic phosphate. These metabolic changes were caused in our opinion by convulsive activity of the brain induced by hypothermia. This was recorded in an electrocorticogram at a brain temperature ranging from 18·9 to 17·8°C over a 150 s period, 5 min before this brain was removed from the animal. These findings demonstrate that hypothermia per se to 24–16°C under our experimental conditions does not cause damage to the rabbit brain, generally, but under special conditions can provoke an increase in energy requirement which exceeds the energy available.
EFFECTS OF SALT AND WATER LOADING ON CARBOHYDRATE AND ENERGY METABOLISM AND LEVELS OF SELECTED AMINO ACIDS IN THE BRAINS OF YOUNG MICE1
Authors: Thurston Jean Holowach , Hauhart R. E. , Jones Elizabeth M. , Ater JoAnn L. 
Published: October 2006

Abstract—This is a report of the effect of extreme changes in plasma sodium concentration induced by chronic (5 d) water deprivation and hypertonic saline injections and acute (4 h) overhydration with hypotonic glucose or fructose on the water and electrolyte content and levels of selected metabolites in the brains of young mice. In the dehydrated hypernatremic mice (plasma Na+, 186 × 3 mequiv./1) significant increases were found in brain glucose (82%), alanine (16%), aspartate (45%), glutamate (19%), gamma‐amino butyrate (34%) and glutamine (42%) concentrations. In striking contrast, water‐intoxicated mice (plasma Na+, 110 × 4 mequiv./1) had significantly decreased levels of alanine (17%), aspartate (38%) and glutamate (33%). Significant reductions in brain lactate (30–40%) and malate concentrations (23%) in both groups of experimental mice are suggestive of reduced cerebral metabolic rate.During adaptation to increased or decreased environmental salinity, levels of amino acids in amphibian brain increase or decrease, respectively, to maintain osmotic equilibrium and to limit the loss or gain of water in brain. The data show that a similar protective response can be evoked in mammalian brain.
CHOLINE ACETYLTRANSFERASE LEVELS IN DIENCEPHALIC NUCLEI OF THE RAT
Authors: Brownstein M. , Kobayashi R. , Palkovits M. , Saavedra J. M. 
Published: October 2006

Abstract—Choline acetyltransferase levels have been measured in specific nuclei of the diencephalon. On the whole, the thalamic nuclei contain higher concentrations of this enzyme than do the hypothalamic and preoptic nuclei. Those nuclei which seem to receive the most dense cholinergic innervation contain the highest levels of choline acetyltransferase.
EVIDENCE THAT 5‐METHOXY‐N, N‐DIMETHYL TRYPTAMINE IS A SPECIFIC SUBSTRATE FOR MAO‐A IN THE RAT: IMPLICATIONS FOR THE INDOLEAMINE DEPENDENT BEHAVIOURAL SYNDROME
Authors: Squires R. F. 
Published: October 2006

Abstract—A simple method for the separation of 5‐hydroxyindoleacetic acid (5‐HIAA) and 5‐methoxyindoleacetic acid (5‐MeOIAA) on columns of non‐ionic polystyrene (Amberlite XAD‐2) is described. Administration of 5‐methoxy‐N, N‐dimethyl‐tryptamine (5‐MeODMT) 2 mg/kg i. p. to rats results in a sixfold increase in brain 5‐MeOIAA within 15 min. This increase is blocked by the selective inhibitor of MAO‐A, clorgyline, but not by the selective inhibitor of MAO‐B, deprenyl, indicating that 5‐MeODMT is deaminated almost entirely by MAO‐A. The apparent 5‐MeOIAA concentration in the brains of L‐tryptophan loaded rats is not reduced by clorgyline and deprenyl, either singly or in combination, indicating that most of this fluorescence is due to other, unidentified substances. The apparent concentration of 5‐HIAA in rat brain, minus 5‐MeOIAA, is unaffected by deprenyl and reduced by clorgyline. However, clorgyline and deprenyl in combination reduced 5‐HIAA values below those obtained with clorgyline alone. It is concluded that very little 5‐MeODMT or other 5‐methoxyindoleamines are formed endogenously in rat brain, and that the stereotyped syndrome of hyperactivity and tremors produced in rats by pretreatment with MAO inhibitors and L‐tryptophan is dependent on the formation of an N‐substituted derivative of 5‐HT which is at least partly deaminated by MAO‐B to 5‐HIAA.
EFFECT OF OUABAIN AND PHENOBARBITAL ON THE KINETICS OF CORTICAL METABOLIC TRANSIENTS ASSOCIATED WITH EVOKED POTENTIALS
Authors: Rosenthal M. , LaManna J. C. 
Published: October 2006

Abstract—Evoked potentials, shifts of the steady potential and spreading depression have been shown to be associated with transient changes in the oxidative metabolic activity of the cerebral cortex of cats. The metabolic activity is measured at the intact surface by intensity of the fluorescence emitted at 460 nm when the tissue is illuminated at 366 nm. The intensity of the fluorescence signal is related to the oxidationreduction level of intramitochondrial NADH which is, itself, related to the ATP/ADP ratio and the rate of oxygen consumption.In this study, the transient changes in metabolic activity with evoked potentials are separated into component parts by means of kinetic analysis. Ouabain (0.1 mM) introduced directly under the cortical surface, markedly slows the ‘on kinetics’ with no change in recovery metabolism. Phenobarbital delays the reduction of NAD+ (‘off kinetics’) with little effect on ‘on kinetics’.Thus, the transient fluorometric response to evoked potentials is confirmed as a measure of ATP breakdown and oxidative rephosphorylation. The rate of NADH oxidation is a measure of the rising ADP concentration due to the action of the Na‐K ATPase. The rate of return of the fluorescence to baseline levels (reduction of NADH) is a function of the respiratory chain.