Search results for "oxidative phosphorylation"

Oxidative Stress and DNA Damage in Obesity-Related Tumorigenesis

2014

Reactive oxygen species induce oxidative modification of critical macromolecules. Oxygen derived free radicals may act as potential cytotoxic intermediates inducing inflammatory and degenerative processes, or as signal messengers for the regulation of gene expression. This dual effect mainly depends on the availability of free radicals in terms of concentration, as well as on the environmental characteristics in which they are produced. The formation of free radicals has been proposed to be the linking factor between certain metabolic disturbances and cancer. Circulating mononuclear cells of patients with high cholesterol levels, insulin resistance, metabolic syndrome or obesity present low…

Forever Young: Structural Stability of Telomeric Guanine-Quadruplexes in Presence of Oxidative DNA Lesions

2020

AbstractHuman telomeric DNA (h-Telo), in G-quadruplex (G4) conformation, is characterized by a remarkable structural stability that confers it the capacity to resist to oxidative stress producing one or even clustered 8-oxoguanine lesions. We present a combined experimental/computational investigation, by using circular dichroism in aqueous solutions, cellular immunofluorescence assays and molecular dynamics (MD) simulations, that identifies the crucial role of the stability of G4s to oxidative lesions, related also to their biological role as inhibitors of telomerase, an enzyme overexpressed in most cancers associated to oxidative stress.

Oxidative cyclization of aldehyde thiosemicarbazones induced by potassium ferricyanide and by tris(p-bromophenyl)amino hexachloroantimoniate. A joint…

2005

The oxidative ring closure reaction of some aryl-substituted thiosemicarbazones induced by "bona fide" one-electron abstracting agents was investigated, by means of both experimental and computational techniques. The corresponding 1,2,4-triazole derivatives were the only cyclization products observed. The occurrence of two slightly different mechanistic pathways for the reaction is discussed.

One-Pot Oxidative C–H Activation/Aza-Prins-Type Reaction of Tertiary Alkynylamines: A Counter Ion-Induced Iminium Ion–Alkyne Cyclization

2021

Herein, the design and development of a new one-pot and metal-free oxidative C-H activation/aza-Prins type cyclization of alkynylamines is reported. The scope of this method was demonstrated by the preparation of ten new pyrido[2,1-a]isoquinolines in moderate to high yields (38-92%). Furthermore, a mechanistic proposal for the alkyne aza-Prins cyclization is described based on DFT calculations.

Oxidative DNA Damage Profiles in Mammalian Cells

1997

Reactive oxygen species (ROS) are formed inside cells not only under the influence of exogenous agents (visible light, ionizing radiation, and many oxidants such as peroxides or quinones), but also under normal (physiological) conditions as byproducts of oxygen metabolism and other cellular redox reactions (Pryor 1986; Halliwell and Gutteridge 1986; Sies 1986; Clayson et al. 1994). ROS such as hydroxyl radicals and singlet oxygen are a serious threat to the integrity of the cellular genome, since they efficiently react with DNA to generate many types of DNA modifications, at least some of which are pre- mutagenic (Breimer 1990; Halliwell and Aruoma 1991; Epe 1991; Feig et al. 1994). Steady-…

Carnitine transport in volume-overloaded rat hearts

1995

Carnitine concentration in tissue is generally related to mitochondrial volume-density and ability to oxidize fatty acids. The highest tissue carnitine has been detected in ventricular myocardium which, compared to other tissues, presents elevated rates of oxidative phosphorylation [1]. The ability of cardiac mitochondria to oxidize long chain fatty acids is also much higher when compared to skeletal muscle or liver sarcosomes (Table 1). Paradoxically enough, it has been known for many years [3–5] that the heart is missing γ-butyrobetaine hydroxylase [6, 7], the last enzyme of carnitine synthesizing pathway, and that in the myocardium of different species including man, the carnitine synthe…

Electrochemical Oxidative C – C Bond Formation

2021

Oxidative damages in cho-k1 cells treated with beauvericin

2013

ChemInform Abstract: Aryl Radicals by Copper(II) Oxidation of Hydrazines: A New Method for the Oxidative and Reductive Arylation of Alkenes.

1990

Abstract A new source of aryl radicals interesting from the preparative point of view has been found in the reaction of arylhydrazines and copper(II) sulfate. The process allows selectively both the reductive and oxidative arylation of alkenes.

Oxidative halogenation of substituted pyrroles with cu(II). Part I. Bromination of some 3-acetylpyrroles

1990

3-Acetylpyrroles are brominated with copper(II) bromide. The reaction afforded almost quantitatively only nuclear monobromination. Evidence for the structures of final compounds was by mass spectrometry, 1 H-nuclear magnetic resonance, ir, and elemental analysis