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181.
Anthony Dobi Susana B. Bravo Bryan Veeren Beatriz Paradela-Dobarro Ezequiel Álvarez Olivier Meilhac 《Free radical research》2019,53(2):150-169
Advanced glycation end-products (AGEs) trigger multiple metabolic disorders in the vessel wall that may in turn lead to endothelial dysfunction. The molecular mechanisms by which AGEs generate these effects are not completely understood. Oxidative stress plays a key role in the development of deleterious effects that occur in endothelium during diabetes. Our main objectives were to further understand how AGEs contribute to reactive oxygen species (ROS) overproduction in endothelial cells and to evaluate the protective effect of an antioxidant plant extract. The human endothelial cell line EA.hy926 was treated with native or modified bovine serum albumin (respectively BSA and BSA-AGEs). To monitor free radicals formation, we used H2DCF-DA, dihydroethidium (DHE), DAF-FM-DA and MitoSOX Red dyes. To investigate potential sources of ROS, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and mitochondrial inhibitors were used. The regulation of different types of ROS by the polyphenol-rich extract from the medicinal plant Doratoxylon apetalum was also studied for a therapeutic perspective. BSA-AGEs exhibited not only less antioxidant properties than BSA, but also pro-oxidant effects. The degree of albumin glycoxidation directly influenced oxidative stress through a possible communication between NADPH oxidase and mitochondria. D. apetalum significantly decreased intracellular hydrogen peroxide and superoxide anions mainly detected by H2DCF-DA and DHE respectively. Our results suggest that BSA-AGEs promote a marked oxidative stress mediated at least by NADPH oxidase and mitochondria. D. apetalum plant extract appeared to be an effective antioxidant compound to protect endothelial cells. 相似文献
182.
Bombesin induces c-fos and c-myc expression in quiescent Swiss 3T3 cells. Comparative study with other mitogens 总被引:6,自引:0,他引:6
R Bravo H Macdonald-Bravo R Müller D Húbsch J M Almendral 《Experimental cell research》1987,170(1):103-115
We have studied the effect of the potent mitogen bombesin on the expression of c-fos and c-myc genes in quiescent mouse fibroblasts. We have demonstrated that bombesin rapidly induces a transient expression of c-fos mRNA followed by a more protracted elevation in c-myc mRNA levels. The intensity of the induction of expression of both proto-oncogenes depended on the dose of bombesin used. Prolonged treatment of the cells with TPA, which causes a selective decrease in protein kinase C activity, partially inhibited the induction of c-fos and c-myc gene expression by bombesin, similar to what has been observed with PDGF. However, a dramatic inhibition of the mitogenic response to bombesin--but not to PDGF--was found in TPA-treated cells. In contrast, TPA-treated cells showed an increased response to EGF with regard to proto-oncogene expression. The role of protein kinase C and Ca2+-dependent pathways in proto-oncogene induction by bombesin is discussed. 相似文献
183.
Stimulation of quiescent 3T3 cells by serum dramatically induces the synthesis of a group of secreted polypeptides with a molecular weight (MW) of 45 K (p45 A, B, C, D). The synthesis of these polypeptides increases 10-fold during the first 2 h. Cycloheximide superinduces the 45 K polypeptides and actinomycin D (actD) blocks completely their induction by serum. Peptide mapping analysis and pulse-chase experiments revealed that p45 A is a precursor of polypeptides p45 B, C, D. Tunicamycin treatment inhibits the synthesis of all four polypeptides but a new related protein appears, p-p45, the unglycosylated precursor. In the presence of tunicamycin, p-p45 is also found in the medium, demonstrating that glycosylation is not essential for the secretion. In vitro translation experiments show that the levels of p45 mRNA present in stimulated cells are severalfold higher than that of non-stimulated cells. Purified growth factors, such as platelet-derived growth factor (PDGF), fibroblast growth factor (FGF) and epidermal growth factor (EGF) induce the synthesis of p45 in quiescent cells. 相似文献
184.
Synthesis, processing, and secretion of rat immunoglobulin E made in Xenopus oocytes 总被引:1,自引:0,他引:1
Rat immunoglobulin E (IgE) synthesized in Xenopus laevis oocytes, injected with rat plasmacytoma mRNA, was analysed by specific immunoprecipitation and SDS-polyacrylamide gel electrophoresis under reducing as well as non-reducing conditions. The results indicate that the oocytes will translate and correctly process the rat IgE heavy and light chains, resulting in secretion of a correctly assembled, normal immunoglobulin molecule. The normal, extensive glycosylation of the IgE heavy chain (e-chain) is faithfully carried out by the oocytes; therefore, this posttranslational modification is apparently of an unspecific nature, and does not depend upon a mechanism specific for plasma cells. 相似文献
185.
Overexpression of ATP Sulfurylase in Indian Mustard Leads
to Increased Selenate Uptake, Reduction, and Tolerance 总被引:28,自引:3,他引:28
Elizabeth A.H. Pilon-Smits Seongbin Hwang C. Mel Lytle Yongliang Zhu Jenny C. Tai Rogelio C. Bravo Yichang Chen Tom Leustek Norman Terry 《Plant physiology》1999,119(1):123-132
In earlier studies, the assimilation of selenate by plants appeared to be limited by its reduction, a step that is thought to be mediated by ATP sulfurylase. Here, the Arabidopsis APS1 gene, encoding a plastidic ATP sulfurylase, was constitutively overexpressed in Indian mustard (Brassica juncea). Compared with that in untransformed plants, the ATP sulfurylase activity was 2- to 2.5-fold higher in shoots and roots of transgenic seedlings, and 1.5- to 2-fold higher in shoots but not roots of selenate-supplied mature ATP-sulfurylase-overexpressing (APS) plants. The APS plants showed increased selenate reduction: x-ray absorption spectroscopy showed that root and shoot tissues of mature APS plants contained mostly organic Se (possibly selenomethionine), whereas wild-type plants accumulated selenate. The APS plants were not able to reduce selenate when shoots were removed immediately before selenate was supplied. In addition, Se accumulation in APS plants was 2- to 3-fold higher in shoots and 1.5-fold higher in roots compared with wild-type plants, and Se tolerance was higher in both seedlings and mature APS plants. These studies show that ATP sulfurylase not only mediates selenate reduction in plants, but is also rate limiting for selenate uptake and assimilation. 相似文献
186.
187.
Carlos M. Rodríguez López Hector Sicilia Bravo Andrew C. Wetten Michael J. Wilkinson 《Molecular breeding : new strategies in plant improvement》2010,25(3):501-516
The scarcity and stochastic nature of genetic mutations presents a significant challenge for scientists seeking to characterise
de novo mutation frequency at specific loci. Such mutations can be particularly numerous during regeneration of plants from
in vitro culture and can undermine the value of germplasm conservation efforts. We used cleaved amplified polymorphic sequence
(CAPS) analysis to characterise new mutations amongst a clonal population of cocoa plants regenerated via a somatic embryogenesis
protocol used previously for cocoa cryopreservation. Efficacy of the CAPS system for mutation detection was greatly improved
after an ‘a priori’ in silico screen of reference target sequences for actual and potential restriction enzyme recognition
sites using a new freely available software called Artbio. Artbio surveys known sequences for existing restriction enzyme
recognition sites but also identifies all single nucleotide polymorphism (SNP) deviations from such motifs. Using this software,
we performed an in silico screen of seven loci for restriction sites and their potential mutant SNP variants that were possible
from 21 restriction enzymes. The four most informative locus-enzyme combinations were then used to survey the regenerant populations
for de novo mutants. We characterised the pattern of point mutations and, using the outputs of Artbio, calculated the ratio
of base substitution in 114 somatic embryo-derived cocoa regenerants originating from two explant genotypes. We found 49 polymorphisms,
comprising 26.3% of the samples screened, with an inferred rate of 2.8 × 10−3 substitutions/screened base. This elevated rate is of a similar order of magnitude to previous reports of de novo microsatellite
length mutations arising in the crop and suggests caution should be exercised when applying somatic embryogenesis for the
conservation of plant germplasm. 相似文献
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