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1.
Influence of Hydrocortisone on Chick Embryo Retina Development 总被引:1,自引:1,他引:0
Renza Vento Giuseppina D'Ancona Michela Giuliano Gennaro Taibi Giovanni Tesoriere 《Journal of neurochemistry》1987,48(6):1693-1698
Treatment of chick embryos in ovo with hydrocortisone-21-phosphate (a single dose of 150 micrograms) caused a marked reduction of retinal thymidine kinase activity 24 h later. The inhibitory effect was highest (65-70%) in 8-10-day-old embryos and declined with age, disappearing after day 15. It was accompanied by a reduction in thickness of the retinal layers. Adrenocorticotropic hormone (ACTH) treatment (10 micrograms daily for 2 days) also produced an age-dependent inhibitory effect on retinal thymidine kinase, whereas treatment with a single dose of 200 micrograms of metopirone, a compound that prevents the 11 beta-hydroxylation of steroid molecules in the adrenal glands, impeded the decrease in thymidine kinase activity that normally occurs in chick embryo retina after day 9 of development. In addition, metopirone prevented the inhibition exerted by ACTH on thymidine kinase activity but had no effect on the action of hydrocortisone. 相似文献
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3.
Application of the dual-cell coulometric detector: a method for assaying monoamines and their metabolites 总被引:3,自引:0,他引:3
A new HPLC assay technique for monoamines and their metabolites, using a controlled potential coulometric detector equipped with a dual working electrode cell of fully porous graphite through which the samples flow, is described in comparison with a classical amperometric detector equipped with a glassy carbon electrode. Different potentials can be applied at each cell of the coulometric detector to improve sample resolution and detection sensitivity. The signal-to-noise ratio (s/n) calculated in similar conditions was 10 times lower for the coulometric detector than for the amperometric one. The dual-coulometric detector does not undergo daily decay or variation, and needs no particular care or preparation. It is therefore possible to achieve stable routine sensitivity in a range of 10 fmol. This new technique has been applied for assaying monoamines and their precursors and metabolites by direct injection of clear supernatant after centrifugation and for determination of catecholamine turnover in rat pineal gland and neuro- and adenohypophysis in samples purified by Al2O3 adsorption. 相似文献
4.
Liver microsomal fractions were prepared from rats injected with a single dose of choline [14C] methylchloride or with single or multiple doses of 32Pi. Exchangeability of microsomal phospholipids was determined by incubation with an excess of mitochondria and phospholipid exchange proteins derived from beef heart, beef liver or rat liver. Labeled phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were found to act as a single pool and were 85–95% exchangeable in 1–2 h. High latencies of mannose-6-phosphate phosphohydrolase activities and impermeability of microsomes to EDTA proved that phospholipid exchange proteins did not have access to the intracisternal space. If microsomal membranes are largely composed of phospholipid bilayers, the experiments suggest that one or more of the phospholipid classes in microsomal membranes undergo rapid translocation between the inner and outer portions of the bilayer. 相似文献
5.
Experiments were performed to detect a possible effect on in vitro irradiated human blood samples. The erythrocyte sedimentation rate (ESR) and the bioimpedence of both treated with a low-level 1.59 kHz electrical field and untreated blood samples were measured. A statistically significant difference (P < 0.001) was found in the blood sedimentation rates between Controls and those exposed to VLF-field condition. The most striking result was that for a 20% of the blood samples analyzed under the influence of the VLF-field, the ESR tests were almost stopped by the latter, i.e. the blood sedimentation did not occur. Bioimpedance value of stopped blood samples were one order of magnitude lower than those of unirradiated samples. 相似文献
6.
P. Perego A. Converti A. Del Borghi P. Canepa 《Bioprocess and biosystems engineering》2000,23(6):613-620
Optimum values of temperature, pH, and starting substrate concentration are experimentally determined for 2,3-butanediol production by Enterobacter aerogenes through three set of batch fermentations of synthetic glucose solutions. The results of tests carried out at variable temperature show an optimum of 39 °C and are used to estimate, for both fermentation and thermal inactivation, the activation enthalpies (7.19 and 23.6 kJ molу) and the related entropies (т.32 and т.27 kJ molу Kу). An optimum pH value of 6.0 is evidenced from batch runs at variable pH, whose results are also used to make reasonable hypotheses on the reaction controlling the metabolic pathway which leads to butanediol. The fermentability of different food industry wastes, namely starch hydrolysate, both raw and decoloured molasses, and whey, is finally checked. 相似文献
7.
Vélez Debora E. Mestre-Cordero Victoria E. Hermann Romina Perego Juliana Harriet Sofia Fernandez-Pazos María de las Mercedes Mourglia Julieta Marina-Prendes M. Gabriela 《Journal of physiology and biochemistry》2020,76(1):85-98
Journal of Physiology and Biochemistry - The cardioprotective activity of rosuvastatin (R) is yet to be known. The objective of this study was to research whether R perfusion before global ischemia... 相似文献
8.
Selwyn Hoeks Mark A. J. Huijbregts Michela Busana Michael B. J. Harfoot Jens-Christian Svenning Luca Santini 《Ecography》2020,43(12):1752-1763
Large carnivores can exert top–down effects in ecosystems, but the size of these effects are largely unknown. Empirical investigation on the importance of large carnivores for ecosystem structure and functioning presents a number of challenges due to the large spatio-temporal scale and the complexity of such dynamics. Here, we applied a mechanistic global ecosystem model to investigate the influence of large-carnivore removal from undisturbed ecosystems. First, we simulated large-carnivore removal on the global scale to inspect the geographic pattern of top–down control and to disentangle the functional role of large carnivores in top–down control in different environmental contexts. Second, we conducted four small-scale ecosystem simulation experiments to understand direct and indirect changes in food-web structure under different environmental conditions. We found that the removal of top–down control exerted by large carnivores (> 21 kg) can trigger large trophic cascades, leading to an overall decrease in autotroph biomass globally. Furthermore, the loss of large carnivores resulted in an increase of mesopredators. The magnitude of these changes was positively related to primary productivity (NPP), in line with the ‘exploitation ecosystem hypothesis’. In addition, we found that seasonality in NPP dampened the magnitude of change following the removal of large carnivores. Our results reinforce the idea that large carnivores play a fundamental role in shaping ecosystems, and further declines and extinctions can trigger substantial ecosystem responses. Our findings also support previous studies suggesting that natural ecosystem dynamics have been severely modified and are still changing as a result of the widespread decline and extinction of large carnivores. 相似文献
9.
Luca Fontanesi Francesca Bertolini Emilio Scotti Giuseppina Schiavo Michela Colombo Paolo Trevisi 《Animal biotechnology》2013,24(2):92-97
The GPR120 gene (also known as FFAR4 or O3FAR1) encodes for a functional omega-3 fatty acid receptor/sensor that mediates potent insulin sensitizing effects by repressing macrophage-induced tissue inflammation. For its functional role, GPR120 could be considered a potential target gene in animal nutrigenetics. In this work we resequenced the porcine GPR120 gene by high throughput Ion Torrent semiconductor sequencing of amplified fragments obtained from 8 DNA pools derived, on the whole, from 153 pigs of different breeds/populations (two Italian Large White pools, Italian Duroc, Italian Landrace, Casertana, Pietrain, Meishan, and wild boars). Three single nucleotide polymorphisms (SNPs), two synonymous substitutions and one in the putative 3′-untranslated region (g.114765469C > T), were identified and their allele frequencies were estimated by sequencing reads count. The g.114765469C > T SNP was also genotyped by PCR-RFLP confirming estimated frequency in Italian Large White pools. Then, this SNP was analyzed in two Italian Large White cohorts using a selective genotyping approach based on extreme and divergent pigs for back fat thickness (BFT) estimated breeding value (EBV) and average daily gain (ADG) EBV. Significant differences of allele and genotype frequencies distribution was observed between the extreme ADG-EBV groups (P < 0.001) whereas this marker was not associated with BFT-EBV. 相似文献
10.