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11.
Taurine Levels in Discrete Brain Nuclei of Rats 总被引:7,自引:1,他引:6
Miklós Palkovits István Elekes Tibor Láng rás Patthy 《Journal of neurochemistry》1986,47(5):1333-1335
Concentrations of taurine have been measured in 44 microdissected rat brain nuclei or areas. Taurine is ubiquitously present and distributed unevenly in the rat brain: the ratio of the highest (pyriform cortex) to lowest (midbrain reticular formation) concentrations is 4.7:1. High taurine levels were found in cerebral cortical areas, caudate-putamen, cerebellum, median eminence, and supraoptic nucleus. Acute pain stress reduced taurine levels in the hypothalamus and the lower brainstem nuclei but not in cortical areas. Increased locomotor and behavioral activities following a high dose of amphetamine elevated taurine concentrations significantly in the substantia nigra and locus ceruleus. 相似文献
12.
Göran Wingstrand 《Physiologia plantarum》1985,64(2):223-229
Membrane-bound MgATPase activity from roots of young sugar beet ( Beta vulgaris L. cv. Monohill) was investigated in a membrane fraction purified by partition in an aqueous polymer two-phase system. After two steps of "washing" with fresh bottom phase (rich in dextran), the polyethylene glycol rich top phase (U3 ) was practically free of mitochondrial membranes (cytochrome oxidase), and the remaining MgATPase activity showed high substrate specificity for ATP. An optimum for the MgATPase activity was found at pH 7. The activation by Na+ or K+ was strongest on the acid side without any observable shift in pH optimum. Oligomycin had no effect, but vanadate strongly inhibited the U3 MgATPase and the K+ activation was lost. The complex activation pattern achieved by varying the Na+ /K+ ratio at constant total concentration was interpreted as a synergistic (Na+ + K+ )-activation. The U3 fraction MgATP-ase activity showed a 4-fold increase in the presence of 0.01% Triton X-100 implying that the MgATPase activity is located in vesicles of which 75% or more are sealed with the ATP binding site on the inside. Comparison with the properties of plasma membrane. ATPases from other plants indicated that the U3 fraction MgATPase was mainly of plasma membrane origin. 相似文献
13.
Autointoxication in residues ofAsparagus officinalis L. 总被引:1,自引:1,他引:0
Summary In a greenhouse experiment the growth of asparagus seedlings was retarded by the residue treatments in both vermiculite and sand cultures. In general, the retardation of asparagus root by residues was slightly greater than the retardation of shoot in both cultures. The retardation of the growth of asparagus seedlings by root and stem treatments was usually higher than that by old root litter. Root and stem extracts strongly inhibited the development of asparagus seedlings in the seed bioassay. The inhibition of extracts to the growth of shoot was greater than that to the growth of root. The quantities in the total phenolics and catachol type phenolics from root, stem and old root litter extracts corresponded to the autotoxicity in the seed bioassay. The soil extracts obtained from using acetone, methanol, and XAD-4 extractions strongly inhibited the shoot and root development of asparagus seedlings in the bioassay. The efficiency of phenolics extraction by the XAD-4 method was significantly higher than that by acetone and methanol extractions. The results obtained in the greenhouse experiment and bioassay revealed that phytotoxic substances present in the residues and the soil of asparagus and may be partially responsible for the asparagus replanting problems. 相似文献
14.
Modelling growth responses of soil nitrifiers to additions of ammonium sulphate and ammonium chloride 总被引:1,自引:0,他引:1
Summary Following the addition of 0–75 mole N g–1 as ammonium chloride or ammonium sulphate to a sandy loam soil the nitrate formed was measured daily for a period of 15–17 days. The nitrate produced as a function of time was described using the Monod equation for microbial growth. An optimisation technique is described for obtaining, from the nitrification time course data, the maximum specific growth rate, the affinity constantant and an index limited by the concentration of ammonium in soil solution. Additions of more than 7.3 moles N g–1 soil as ammonium chloride were found to inhibit nitrification. The inhibition was interpreted as being caused by osmotic pressure or by chloride ion. A similar effect was not found with ammonium sulphate, because the salt concentration in the soil solution was restricted by the precipitation of calcium sulphate. The model developed was capable of accounting for nitrate production in the soil under non-steady state conditions of substrate concentrations and nitrifier biomass. 相似文献
15.
Basic and Regulatory Mechanisms of In Vitro Release of Met-Enkephalin from the Dorsal Zone of the Rat Spinal Cord 总被引:6,自引:3,他引:3
Abstract: Under control conditions, superfused slices of the dorsal half of the lumbar enlargement from adult rats released Met-enkephalin-like material (MELM) that behaved as authentic Met-enkephalin under two different chromatographic procedures (Bio-gel filtration, HPLC). MELM release increased markedly on exposure of slices to batrachotoxin (0.5 μ M ) or to an excess of K+ (28 and 56 m M instead of 5.6 m M ). The K + -evoked release was totally dependent on the presence of Ca2+ in the super-fusing fluid whereas the spontaneous efflux of MELM was only partially Ca2+ -dependent. Further experiments performed with tissues of polyarthritic rats indicated that the increase in their MELM levels was associated with a lower fractional rate constant of MELM release, therefore suggesting that spinal Met-enkephalin turnover might be reduced in chronically suffering animals. Examination of the possible modulation of MELM release by various neuroactive compounds present within the dorsal horn revealed that cholecystokinin (10 μ M ), but not its desulphated derivative, substance P-sulphoxide (10 μ M ), and to a lesser extent substance P, enhanced the K+ -evoked MELM release. In contrast, γ-aminobutyric acid (10 μ M ) and (–)-baclofen (1 μ M ) partially prevented the stimulatory effect of K+ on MELM release. Other compounds such as serotonin, somatostatin, and neurotensin altered neither the spontaneous nor the K+ -evoked release of MELM. 相似文献
16.
17.
Further studies on theisfA mutation responsible for anti-SOS and antimutagenic activities inEscherichia coli are described. We have previously shown that theisfA mutation inhibits mutagenesis and other SOS-dependent phenomena, possibly by interfering with RecA coprotease activity. TheisfA mutation has now been demonstrated also to suppress mutator activity inE. coli recA730 andrecA730 lexA51(Def) strains that constitutively express RecA coprotease activity. We further show that the antimutator activity of theisfA mutation is related to inhibition of RecA coprotease-dependent processing of UmuD. Expression of UmuD' from plasmid pGW2122 efficiently restores UV-induced mutagenesis in therecA730 isfA strain and partially restores its mutator activity. On the other hand, overproduction of UmuD'C proteins from pGW2123 plasmid markedly enhances UV sensitivity with no restoration of mutability. 相似文献
18.
19.
Jane Stratford Michael A. Wright Walter Reineke Heiner Mokross Jurgen Havel Christopher J. Knowles Gary K. Robinson 《Archives of microbiology》1996,165(3):213-218
Chlorobenzoates (CBA) arise as intermediates during the degradation of polychlorinated biphenyls (PCBs) and some chlorinated herbicides. Since PCBs were produced as complex mixtures, a range of mono-, di-, and possibly trichloro-substituted benzoates would be formed. Chlorobenzoate degradation has been proposed to be one of the rate-limiting steps in the overall PCB-degradation process. Three hybrid bacteria constructed to have the ability to completely mineralise 2-, 3-, or 4-monochlorobiphenyl respectively, have been studied to establish the range of mono- and diCBAs that can be utilised. The three strains were able to mineralise one or more of the following CBAs: 2-, 3-, and 4-monochlorobenzoate and 3,5-dichlorobenzoate. No utilisation of 2,3-, 2,5-, 2,6-, or 3,4-diCBA was observed, and only a low concentration (0.11 mM) of 2,4-diCBA was mineralised. When the strain with the widest substrate range (Burkholderia cepacia JHR22) was simultaneously supplied with two CBAs, one that it could utilise plus one that it was unable to utilise, inhibitory effects were observed. The utilisation of 2-CBA (2.5 mM) by this strain was inhibited by 2,3-CBA (200 M) and 3,4-CBA (50 M). Although 2,5-CBA and 2,6-CBA were not utilised as carbon sources by strain JHR22, they did not inhibit 2-CBA utilisation at the concentrations studied, whereas 2,4-CBA was co-metabolised with 2-CBA. The utilisation of 2-, 3-, and 4-chlorobiphenyl by strain JHR22 was also inhibited by the presence of 2,3- or 3,4-diCBA. We conclude that the effect of the formation of toxic intermediates is an important consideration when designing remediation strategies.Abbreviations
PCB
Polychlorinated biphenyl
-
CBA
Chlorobenzoate 相似文献
20.