Search results for "SIDA"
showing 10 items of 1584 documents
A short-range gradient of histone H3 acetylation and Tup1p redistribution at the promoter of the Saccharomyces cerevisiae SUC2 gene.
2003
Chromatin immunoprecipitation assays are used to map H3 and H4 acetylation over the promoter nucleosomes and the coding region of the Saccharomyces cerevisiae SUC2 gene, under repressed and derepressed conditions, using wild type and mutant strains. In wild type cells, a high level of H3 acetylation at the distal end of the promoter drops sharply toward the proximal nucleosome that covers the TATA box, a gradient that become even steeper on derepression. In contrast, substantial H4 acetylation shows no such gradient and extends into the coding region. Overall levels of both H3 and H4 acetylation rise on derepression. Mutation of GCN5 or SNF2 lead to substantially reduced SUC2 expression; in…
A microplate version of the SOS/umu-test for rapid detection of genotoxins and genotoxic potentials of environmental samples
1991
Abstract The umu-microtest is a miniaturized automated short-term test version proposed for screening of umuC-dependent mutagenic potentials of chemicals relevant to environmental pollution, river water and industrial waste water. The test is based on the SOS/umu-test and has been modified in order to allow extensive testing of environmental samples. Genetically engineered Salmonella typhimurium (TA1535/pSK1002) are incubated on a microplate rotor in a sloping position for 2 h with the test samples, followed by addition of fresh culture medium to reach a 10-fold dilution of the incubation medium. 2 h later, the activity of the β-galactosidase, which reflects umuC induction, is determined co…
Evaluation of the SOS/umu-test post-treatment assay for the detection of genotoxic activities of pure compounds and complex environmental mixtures.
2000
This study presents an evaluation of the SOS/umu-test after introducing an additional dilution and incubation in the post-treatment assay. This treatment reduces the influence of coloured test compounds that otherwise affect the colorimetric determination of the beta-galactosidase activity and the bacterial growth measurement during the testing of complex environmental samples. The post-treatment assay significantly increased the beta-galactosidase activity and consequently the enzyme induction ratios at higher doses of model genotoxins 4-nitroquinoline-N-oxide, N-methyl-N'-nitro-N-nitrosoguanidine, 2-aminoanthracene, benzo(a)pyrene with low or no effect on the sensitivity of the test itsel…
Increase of sensitivity and validity of the SOS/umu-test after replacement of the beta-galactosidase reporter gene with luciferase.
1998
The SOS/umu-test with Salmonella typhimurium TA1535/pSK1002 as tester strain is a rapid and valuable bacterial assay for screening of umuC-dependent mutagenic potential of chemical compounds and chemicals relevant to environmental pollution. The initial assay was modified by replacing the beta-galactosidase reporter gene with luciferase. Thereby, the sensitivity of the umu-test was increased significantly and the susceptibility to intensively coloured solutions was reduced. The alternative enzyme assay in the modified umu-test (umu-Luc) represents an independent method which allows to confirm the colorimetric results obtained with the original SOS/umu-test system (umu-Gal) by measuring the …
The Mediterranean Sanctuary for the Protection of Marine Mammals
1999
Tras una breve descripción de la única zona declarada como Santuario Mediterráneo para la protección de los mamíferos marinos, el presente trabajo comenta algunos aspectos jurídicos relativos a este Santuario marino. En primer lugar, centro la atención en la forma cómo se estableció este Santuario marino. Tras diversas iniciativas de diferentes organizaciones no gubernamentales, Italia, Francia y Mónaco establecieron unilateralmente este Santuario marino en sus respectivas legislaciones nacionales y, posteriormente, estos mismos tres Estados adoptaron un convenio internacional hacia este objetivo. Este instrumento internacional se conoce como la Declaración conjunta por la que se establece …
Consumer Demand for Environmental, Social, and Ethical Information in Fishery and Aquaculture Product Labels
2022
[EN] Customers' attention to sustainability labels in fishery and aquaculture products (FAPs) has been increasing in the last decades, and the industry has adapted to this growing interest by adopting fish ecolabels. However, there is a growing interest to widen the sustainability concept to include the social and ethical information of the fishery and aquaculture industry and to go further from the voluntary approach on the labeling of these aspects in FAPs. For this reason, using data from 2021 Eurobarometer and using machine learning techniques, we disentangle the characteristics of the FAP buyers that consider the importance of environmental impact, ethical, and social information appea…
Enseñanza de las ciencias : revista de investigación y experiencias didácticas
2021
La biodiversidad es un concepto complejo, convertido en un importante referente curricular. Esta investigación explora si un ejercicio avanzado de las competencias necesarias para hacer significativo el concepto de biodiversidad en diferentes contextos conlleva una mejora significativa de la calidad de los argumentos implicados en la toma de decisiones sobre conservación de la biodiversidad. Para ello se ha aplicado una metodología cualitativa al análisis de doce argumentos formulados por estudiantes de 1.º de Bachillerato, caracterizados por su elevada complejidad estructural, de los cuales se muestra uno a modo de ejemplo. Los resultados revelan que, a pesar del nivel de cohesión estructu…
Overexpression of apolipoprotein J in human fibroblasts protects against cytotoxicity and premature senescence induced by ethanol and tert-butylhydro…
2008
Human diploid fibroblasts (HDFs) exposed to subcytotoxic stresses under H2O2, tert-butylhydroperoxide (t-BHP), and ethanol (EtOH) undergo stress-induced premature senescence (SIPS) characterized by many biomarkers of HDFs replicative senescence. Among these biomarkers are a growth arrest, an increase in the senescence-associated β-galactosidase activity, a senescent morphology, an overexpression of p21waf-1 and the subsequent inability to phosphorylate pRb, the presence of the common 4977-bp mitochondrial deletion, and an increase in the steady-state level of several senescence-associated genes such as apolipoprotein J (apo J). Apo J has been described as a survival gene against cytotoxic s…
DNA damage causes TP53-dependent coupling of self-renewal and senescence pathways in embryonal carcinoma cells.
2013
Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fract…