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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 45 (1985), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: An increase of free 3,4-dihydroxyphenylethylamine (DA, dopamine) in the rat brain such as is found following 3,4-dihydroxyphenylalanine (L-DOPA) administration or an intraventricular injection of free dopamine did not result in DA sulfate formation, despite the presence of phenolsulfotransferase activity in various regions of the brain and the high affinity of DA for this enzyme. However, when rats were pretreated with pargyline, a monoamine oxidase inhibitor, the same treatment with L-DOPA or free DA led to active synthesis of DA sulfate. The increase in DA sulfate was significantly correlated with the degree of monoamine oxidase inhibition and directly proportional to free DA concentrations in the hypothalamus (r = 0.86), striatum (r = 0.54), and brain-stem (r = 0.89). The highest ratio of DA sulfate to free DA was found in the hypothalamus, suggesting that sulfoconjugation is most active in this region. Prior treatment of rats with 6-hydroxydopamine did not decrease DA sulfate concentrations, indicating that sulfoconjugation occurs most likely in extraneuronal tissues not destroyed by the neurotoxin. The results are compatible with the notion that phenolsulfotransferase may be highly compartmentalized and that inhibition of monoamine oxidase allows the newly generated free DA to become accessible to the sulfoconjugating enzyme, resulting in increase in DA sulfation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effects of subeutaneous injection of l-β-3,4-dihydroxyphenylalanine (l-DOPA) on the concentrations of the catecholamines and catecholamine sulfates in the central and peripheral nervous Systems of the rat were studied. The results showed that free 3,4-dihydroxyphenylethylamine (DA, dopamine) increased rapidly and markedly in the hypothalamus and striatum after l-DOPA but DA sulfate did not change. Increased concentrations of DA sulfate were detected in the CSF and in the plasma, where it reached a concentration of 130.8 ± 12.8 ng/ml at 2 h, seven times the level of free DA (19.1 ± 2.9 ng/ml). In the kidney the ratio of DA sulfate to free DA was reversed in favor of free DA. Urine samples of l-DOPA-treated rats showed a higher increase of free DA than DA sulfate, but free norepinephrine (NE) and NE sulfate remained unchanged. Concentrations of free DA and free NE in the adrenal glands of l-DOPA-treated rats showed no change. Adrenal DA sulfate and NE sulfate were not detectable in the control and l-DOPA-treated rats, suggesting that the adrenal glands lack the capacity to take up or store catecholamines and their sulfate counterparts from the plasma.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: In the present study, we found that large quantities of dopamine (DA) glucuronide were present in rat cerebrospinal fluid (CSF), plasma, and urine, whereas the glucuronides of norepinephrine (NE) and epinephrine (E) were almost undetectable. The high urinary excretion of DA glucuronide was in a range comparable to that of homovanillic acid (HVA). Sulfates of DA, NE, and E were measurable in all three body fluids, but only in small quantities. The measured DA glucuronide was predominantly of endogenous origin, as the feeding of sucrose instead of routine diet did not reduce the urinary output of DA glucuronide. Adrenalectomy but not peripheral sympathectomy induced by chronic guanethidine injection substantially decreased plasma DA glucuronide concentrations, indicating that the adrenals serve as an important source of endogenous DA glucuronide. The data suggest that glucuronidation constitutes an important metabolic pathway for endogenous DA of central and peripheral origin in rats; this route, however, is exclusive to DA and appears to play a negligible role for NE and E.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 70 (1987), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Shoots from two ecologically different evergreen tree species, Picea abies (L.) Karst and Coffea liberica Hiern, were used to carry out pressure volume (PV) measurements at 5–35°C. For this purpose a pressure chamber was equipped with thermoelectric temperature regulation. The non-linear sections of the resultant PV curves were sigmoidal for both species, with recognizable points of inflexion. These points, at around ψ= 1.12 MPa and relative water content (RWC) = 88.5% for Picea and at ψ= 0.92 MPa and RWC = 95.5% for Coffea, were characterised by a temporary increase in the resistance to water flow of the entire shoot (R5).The maximum value of the bulk modulus of elasticity (ɛ max) was also in the region of the point of inflexion. This value was considerably higher in Coffea than in Picea. The osmotic pressures at full water saturation (π0) and at turgor loss point (πp) showed a clear temperature dependence between 15 and 35°C differing only slightly from the theoretically expected situation. At 25°C these values were 1.72 and 2.48 MPa. respectively, for Picea and 1.58 and 1.87 MPa. respectively, for Coffea. The turgor loss point occurred at 76–77% RWC in Picea and at 86% RWC in Coffea, the proportion of apoplastic water varied between 22 and 25% in Picea but was only 9–10% in Coffea. The ecological differences between the two species are reflected in their temperature dependence for R5, which was much steeper for Coffea than for Picea. The energy of activation for the water conductance of the whole shoots was 13.0–14.4 kJ mol−1 in Picea and about 23 kJ mol−1 in Coffea.
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  • 5
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The biochemical, sensory, and quality changes that occur during processing and prolonged frozen storage of kiwifruit pulp were studied. The temperature and processing time during pulp manufacture and freezing are critical factors in determining the % total chlorophyll and color of the frozen pulp. Storage of pulp at acceptable commercial frozen storage temperatures (−18°C or below) for 12 months resulted in a stable color, and a slight decrease in the % total chlorophylls and ascorbic acid. The type of packaging material used and deaeration of pulp did not influence the above findings. The sensory qualities of the pulp were not affected by the storage conditions.
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  • 6
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
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  • 7
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anthocyanins from red raspberry juice concentrates were extracted with acidified ethanol and methanol and separated by high performance liquid chromatography. Six anthocyanin peaks were identified as cyanidin-3-sophoroside (cy-3-sop), cyanidin-3-glucorutinoside (cy-3-glru), cyanidin-3-glucoside (cy-3-gl), cyanidin-3-rutinoside (cy-3-ru), pelargonidin-3-sophoroside (pg-3-sop), and pelargonidin-3-glu-corutinoside (pg-3-glru). Relative proportions of individual anthocyanins were determined by comparing peak areas. The proportions of cy-3-sop, cy-3-glru and cy-3-gl in particular changed greatly on storage for 3 mo at + 20°C. Minor changes occurred when the raspberry juice concentrate was stored at −20°C.
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  • 8
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Freezing points of orange juices and model sugar-acid-water systems at various solute concentrations were investigated using models of solution theory. The observed freezing point depression values of citrus juice were less than those of the model system of comparable average molecular weight. The differences were characterized by a parameter which accounted for the solute-solvent interactions. Models with generalized values were presented which allowed the prediction of equilibrium freezing curves of fruit juices based on proximate sugar-acid composition.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 52 (1987), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pectin was extracted from whole kiwifruit at a mean yield of 0.85%. The analytical properties of the crude kiwifruit pectin extract were compared with those of a commercially available apple pectin. The kiwifruit pectin exhibited a high gelling temperature of 90°C.
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  • 10
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Levels of glutamine synthetase (GS) biosynthetic activity, GS protein and GS mRNA were compared in the parent strain of Anabaena variabilis and in ammonia-liberating mutant strains (ED81 and ED92) which are resistant to ethylenediamine (EDA). GS activity, protein and mRNA levels were all reduced in ED92 whereas ED81 had levels of GS protein and mRNA similar to those of the parent strain but had much reduced GS biosynthetic activity. These findings are discussed in relation to the type of mutation occurring within in each mutant strain and in relation to the reduced GS activity in the Anabaena-Azolla symbiotic association.
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