Search results for "Reactive"
showing 10 items of 1469 documents
Saccharomyces cerevisiae Glutaredoxin 5-deficient Cells Subjected to Continuous Oxidizing Conditions Are Affected in the Expression of Specific Sets …
2004
The Saccharomyces cerevisiae GRX5 gene codes for a mitochondrial glutaredoxin involved in the synthesis of iron/sulfur clusters. Its absence prevents respiratory growth and causes the accumulation of iron inside cells and constitutive oxidation of proteins. Null ⌬grx5 mu- tants were used as an example of continuously oxidized cells, as opposed to situations in which oxidative stress is instantaneously caused by addition of external oxi- dants. Whole transcriptome analysis was carried out in the mutant cells. The set of genes whose expression was affected by the absence of Grx5 does not significantly overlap with the set of genes affected in respiratory petite mutants. Many Aft1-dependent ge…
DNA Oxidation Photoinduced by Norharmane Rhenium(I) Polypyridyl Complexes: Effect of the Bidentate N,N′-Ligands on the Damage Profile
2018
Re(I)--polypyridyl complexes have interesting and distinctive photochemical and photosensitizing properties. This work describes the capability to induce (or photoinduce) DNA damage of three Re(I)-complexes with a naturally occurring alkaloid called norharmane (nHo) as ligand: [Re(CO)₃ (nHo)(L)]CF₃ SO₃ where L=2,2'-bipyridine (ReBpy), phenanthroline (RePhen) or dipyrido[3,2-a:2',3'-c]phenazine (ReDppz). The interaction of the complexes with DNA was investigated by steady-state and time-resolved spectroscopy. Data show that the mode and strength of interaction depend on the chemical structure of the bidentate ligand. The complexes show a major static contribution to the overall interaction, …
Enterobacteria-infected T cells as antigen-presenting cells for cytotoxic CD8 T cells: a contribution to the self-limitation of cellular immune react…
1997
In enterobacteria-induced reactive arthritis (ReA), different T cell subsets play a role in the induction and maintenance of the synovitic process. Synovial fluid-derived alphabeta CD4, alphabeta CD8, and gammadelta T lymphocyte clones (TLC) that recognize Yersinia or Salmonella antigens on professional antigen-presenting cells (APC) have been characterized, and T cells themselves can function as nonprofessional APC. T cells were infected with the facultatively intracellular, arthritogenic enterobacterium Yersinia enterocolitica O:3. A CD8 TLC isolated from a patient with Yersinia-induced ReA recognized and efficiently lysed autologous and allogeneic Yersinia-infected T cells. Infected cyto…
Inflammation and sarcopenia: A systematic review and meta-analysis
2017
Inflammatory cytokines have been shown to prompt muscle wasting, ultimately stimulating protein catabolism and suppressing muscle synthesis. However, the possible association between inflammatory parameters and sarcopenia is poorly understood. We therefore aimed to summarize the current evidence about this topic with a meta-analysis of studies reporting serum inflammatory parameters in patients with sarcopenia vs. people without sarcopenia (controls). An electronic PubMed and Scopus search through to 09/01/2016 and meta-analysis of cross-sectional studies comparing serum levels of inflammatory cytokines between patients with sarcopenia and controls was made, calculating random-effects stand…
Inactivity-induced oxidative stress: A central role in age-related sarcopenia?
2012
Ageing causes a progressive decline in skeletal muscle mass that may lead to decreased strength and functionality. The term sarcopenia is especially used to characterise this geriatric syndrome. Numerous conditions and behaviours are considered to accelerate the progression of sarcopenia such as chronic diseases, malnutrition and physical inactivity. As people in modern countries are more and more sedentary, the impact of physical inactivity on the prevalence of sarcopenia might be more and more important in the future. In this review, we discuss how reactive oxygen species (ROS) could mediate the effects of lifelong inactivity in the onset and progression of age-related sarcopenia. Althoug…
When the brain goes diving: glial oxidative metabolism may confer hypoxia tolerance to the seal brain.
2009
Deep diving mammals have developed strategies to cope with limited oxygen availability when submerged. These adaptations are associated with an increased neuronal hypoxia tolerance. Brain neurons of the hooded seal Cysto- phora cristata remain much longer active in hypoxic condi- tions than those of mice. To understand the cellular basis of neuronal hypoxia tolerance, we studied neuroglobin and cy- tochrome c in C. cristata brain. Neuroglobin, a respiratory protein typically found in vertebrate neurons, displays three unique amino acid substitutions in hooded seal. However, these substitutions unlikely contribute to a modulation of O2 affinity. Moreover, there is no significant difference i…
Oxidative stress in environmental-induced carcinogenesis.
2009
Reactive oxygen species (ROS) are the more abundant free radicals in nature and have been related with a number of tissue/organ injuries induced by xenobiotics, ischemia, activation of leucocytes, UV exposition, etc. Oxidative stress is caused by an imbalance between ROS production and a biological system's ability to readily detoxify these reactive intermediates or easily repair the resulting damage. Thus, oxidative stress is accepted as a critical pathophysiological mechanism in different frequent human pathologies, including cancer. In fact ROS can cause protein, lipid, and DNA damage, and malignant tumors often show increased levels of DNA base oxidation and mutations. Different lifesty…
Oxidative Stress and the Epigenetics of Cell Senescence: Insights from Progeroid Syndromes.
2019
Background: Cell senescence constitutes a critical process to respond to a variety of insults and adverse circumstances. Senescence involves the detention of DNA replication and cell proliferation, and hence, genetic programs associated with DNA damage response, chromosome stability, chromatin rearrangement, epigenetic reprogramming, and cell cycle are tightly linked to the senescent phenotype. Although senescence increases with age, the real implication of senescence regulation in the progress of aging in humans is largely discussed. In this context, reactive oxygen species (ROS) accumulation has also been postulated to play a critical role in cell homeostasis, aging processes, and contro…
The dual role of p53: DNA protection and antioxidant.
2011
The classical functions of p53 protein are those related to its role on DNA damage, cell growth arrest, senescence and apoptosis. For this reason it is called 'the guardian of the genome' and is considered one of the most important players in the development of cancer. However, more recently it has been show that p53 is not only involved in cancer, but also in ageing. p53 is stimulated by stress, which in turn results in the activation of a wide range of transcriptional targets. Low-intensity stress will activate p53 in a manner which results in antioxidant response, thus protecting against ageing because of its antioxidant function. On the contrary, high-intensity activation of p53 will re…
The role of mitochondrial oxidative stress in aging.
2003
Mitochondria are both a major source of oxidants and a target for their damaging effects, and, therefore, mitochondrial oxidative stress appears to be a cause, rather than a consequence, of cell aging. Oxidative damage in aging is particularly high in specific molecular targets, such as mitochondrial DNA and aconitase, and mitochondrial oxidative stress may drive tissue aging through intrinsic apoptosis. Mitochondrial function and morphology are impaired upon aging, as judged by a decline in membrane potential as well as by an increase in peroxide production and size of the organelles. In view of the age-related decreases in mitochondrial protein synthesis, mitochondrial transcripts, and ex…