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171.
Immunocytochemistry revealed growth hormone-releasing hormone (GRF)-containing cells (4-10/50 microns thick coronal sections) in the ventral portion of the medial parvicellular subdivision of the paraventricular nucleus (PVN) in the rat. In the same region we also detected about the same number of neurons containing the mRNA that encodes GRF using in situ hybridization histochemistry. Fluorescence double labelling immunohistochemistry showed the presence of GRF and tyrosine hydroxylase (TH) in the same PVN neurons. The overlap between the two populations of cells is only partial: less than half of TH-positive cells contain GRF and vice versa. 相似文献
172.
The rate of lipid lateral diffusion has been investigated by computer simulation of electron spin resonance (ESR) spectra of spin-labelled dimyristoyl phosphatidylcholine (DMPC) vesicles. An optimization method has been developed to fit the experimental spectra to the theoretical ones calculated from the modified Bloch-equations in order to determine frequencies of probe-probe collisions and the lipid lateral diffusion coefficients. The main results of this study are: (i) Due to the sensitivity of our method to the extent of the overlapping of hyperfine spectral lines it is possible to determine the spin exchange contribution to linebroadening. (ii) It is obvious from these computer analyses that over a wide range of temperatures well above the phase transition both static dipolar interaction and dynamic spin exchange make significant contributions to the linebroadening. (iii) Lipid lateral diffusion coefficient in DMPC bilayers at 36 degrees C was (2.3 +/- 0.2) x 10(-11) m2 s-1. 相似文献
173.
Bacteriophage M13 major coat protein has been incorporated at different lipid/protein ratios in lipid bilayers consisting of various ratios of dimyristoylphosphatidylcholine (DMPC) to dimyristoylphosphatidylglycerol (DMPG). Spin-label ESR experiments were performed with phospholipids labeled at the C-14 position of the sn-2 chain. For M13 coat protein recombinants with DMPC alone, the relative association constants were determined for the phosphatidylcholine, phosphatidylglycerol, and phosphatidic acid spin-labels and found to be 1.0, 1.0, and 2.1 relative to the background DMPC, respectively. The number of association sites for each phospholipid on the protein was found to be 4 per protein monomer. The intrinsic off-rates for lipid exchange at the intramembranous surface of the protein in DMPC alone at 30 degrees C were found to be 5 X 10(6), 6 X 10(6), and 2 X 10(6) s-1 for the phosphatidylcholine, phosphatidylglycerol, and phosphatidic acid spin-labels, respectively. Adding DMPG to the DMPC lipid system increased the exchange rates of the lipids on and off the protein. By gel filtration chromatography, it is found that protein aggregation is reduced after addition of DMPG to the lipid system. This is in agreement with measurements of tryptophan fluorescence, which show a decrease in quenching efficiency after introduction of DMPG in the lipid system. The results are interpreted in terms of a model relating the ESR data to the size of the protein-lipid aggregates. 相似文献
174.
175.
The role of salicylic acid (SA) as a key molecule in the signal transduction pathway of biotic stress responses has already
been well described. Recent studies indicate that it also participates in the signaling of abiotic stresses. The application
of exogenous SA could provide protection against several types of stresses such as high or low temperature, heavy metals,
and so on. Although SA may also cause oxidative stress to plants, partially through the accumulation of hydrogen peroxide,
the results published so far show that the preliminary treatment of plants with low concentrations of SA might have an acclimation-like
effect, causing enhanced tolerance toward most kinds of abiotic stresses due primarily to enhanced antioxidative capacity.
The effect of exogenous SA depends on numerous factors such as the species and developmental stage of the plant, the mode
of application, and the concentration of SA and its endogenous level in the given plant. Recent results show that not only
does exogenous SA application moderate stress effects, but abiotic stress factors may also alter the endogenous SA levels
in the plant cells. This review compares the roles of SA during different abiotic stresses. 相似文献
176.
177.
N Perricone K Nagy F Horváth G Dajkó I Uray I Zs-Nagy 《Biochemical and biophysical research communications》1999,262(3):661-665
The OH(*) free radical scavenging properties of ascorbyl palmitate (AP), water-solubilized in the presence of a surfactant (Brij 35), were tested in various systems: (1) The inhibition of polymerization of bovine serum albumin by OH(*) free radicals generated by the Fenton reaction indicated AP exerts a considerable protective effect against polymerization by scavenging the OH(*) free radicals. (2) ESR spin trapping comparisons of DMPO with AP were conducted. Using the Fenton reaction as a source of OH(*) free radicals, AP was 1 order of magnitude faster in scavenging these radicals than DMPO. (3) Oxidative modification of BSA by (60)Co-gamma irradiation of 80 krad, results in a strong increase in protein carbonyl content. AP inhibits carbonyl formation very efficiently, indicating that AP may be utilized as a biological OH(*) free radical scavenger in human therapy. 相似文献
178.
The effect of morphine on plasma prolactin level and on dopamine turnover in the median eminence was studied using adult male rats chronically treated with ACTH. It was found that the ACTH pretreatment caused a decrease in the effect of morphine on prolactin secretion and prevented the inhibitory effect of morphine on dopamine turnover measured in the median eminence. The prolonged ACTH administration did not influence the prolactin content of the pituitaries and the in vitro dopamine sensitivity of lactotroph cells. Acute dexamethasone injection did not change the morphine-caused prolactin release. These results suggest that chronic ACTH treatment (possibly via corticosterone hyperproduction) elicits an opiate-tolerance like state of tuberoinfundibular dopaminergic neurons. 相似文献
179.
180.
Lóry Viktória Balážová Lucia Kršková Katarína Horváthová Ľubica Olszanecki Rafal Suski Maciej Zórad Štefan 《Journal of physiology and biochemistry》2019,75(3):351-365
Journal of Physiology and Biochemistry - There is a gap in the knowledge regarding regulation of local renin–angiotensin system (RAS) in skeletal muscle during development of obesity and... 相似文献