oxidative stress

(noun)

Damage caused to cells or tissue by reactive oxygen species.

Related Terms

  • NADPH
  • sigma factor
  • RpoS protein
  • glycolysis

Examples of oxidative stress in the following topics:

  • Regulation of Sigma Factor Translation

    • The RpoS is critical in the general stress responses and can either function in promoting survival during environmental stresses, but can also prepare the cell for stresses.
    • Small noncoding RNAs are able to sense environmental changes and stresses resulting in increased expression of RpoS protein.
    • These small noncoding RNAs are capable of sensing changes in temperature (DsrA), cell surface stress (RprA) and oxidative stress (OxyS).
  • The Pentose Phosphate Shunt

    • There are two distinct phases in the pathway: the oxidative phase and the non-oxidative phase .
    • The first is the oxidative phase in which glucose-6-phosphate is converted to ribulose-5-phosphate.
    • The second phase of this pathway is the non-oxidative synthesis of 5-carbon sugars.
    • Additionally, NADPH can be used by cells to prevent oxidative stress.
    • Outline the two major phases of the pentose phosphate shunt: oxidative and non-oxidative phases
  • Bacterial Differentiation

    • However, this consistency could be affected in some circumstances (such as environmental stress) and changes in bacterial shape and size.
    • For instance, rod shapes may allow bacteria to attach more readily in environments with shear stress (e.g., in flowing water).
    • Oxidative stress, nutrient limitation, DNA damage and antibiotics exposure are some stress conditions to which bacteria respond, altering their DNA replication and cell division.
    • Filamentous bacteria have been considered to be over-stressed, sick and dying members of the population.
    • Nutritional stress can change bacterial morphology.
  • Dissociation

    • Coping is expending conscious effort to solve personal and interpersonal problems, and seeking to minimize or tolerate stress or conflict.
    • Coping through dissociation is often associated with post-traumatic stress syndrome.
    • Substances with dissociative properties include ketamine, nitrous oxide, alcohol, LSD, tiletamine, marijuana, dextromethorphan, PCP, methoxetamine, salvia, and muscimol.
    • Dissociative disorders are sometimes triggered by trauma, but may be preceded only by stress, psychoactive substances, or no identifiable trigger at all.
  • General Properties of Metals

    • Typically they are malleable and ductile, deforming under stress without cleaving.
    • An example is the reaction with oxygen in the air to form oxides over various timescales (iron rusts over years, while potassium burns in seconds).
    • The transition metals (such as iron, copper, zinc, and nickel) are slower to oxidize because they form a passivating layer of oxide that protects the interior.
    • Some metals form a barrier layer of oxide on their surface, which cannot be penetrated by further oxygen molecules.
  • Oxidation Numbers of Metals in Coordination Compounds

    • Transition metals typically form several oxidation states and therefore have several oxidation numbers.
    • This oxidation number is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound.
    • O2- and S2- have oxidation numbers of -2.
    • In a molecule or compound, the oxidation number is the sum of the oxidation numbers of its constituent atoms.
    • The oxidation number of H is +1 (H+ has an oxidation number of +1).
  • Oxides

    • Metal oxides typically contain an anion of oxygen in the oxidation state of −2.
    • Most of the Earth's crust consists of solid oxides, the result of elements being oxidized by the oxygen in air or water.
    • Although most metal oxides are polymeric, some oxides are monomeric molecules.
    • Those attacked only by acids are basic oxides; those attacked only by bases are acidic oxides.
    • Metals tend to form basic oxides, non-metals tend to form acidic oxides, and amphoteric oxides are formed by elements near the boundary between metals and non-metals (metalloids).
  • Properties of Quartz and Glass

    • Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron (II) oxide (FeO) impurities of up to 0.1 % by weight produce a green tint.
    • Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide.
    • When used in art glass or studio glass, glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures, and 'cook' times.
    • Piezoelectricity is the ability to develop an electric potential upon the application of mechanical stress.
    • An early use of this property of quartz crystals was in phonograph pickups, where the mechanical movement of the stylus in the groove generates a proportional electrical voltage by creating stress within a crystal.
  • Oxidations & Reductions

    • A parallel and independent method of characterizing organic reactions is by oxidation-reduction terminology.
    • Carbon atoms may have any oxidation state from –4 (e.g.
    • Fortunately, we need not determine the absolute oxidation state of each carbon atom in a molecule, but only the change in oxidation state of those carbons involved in a chemical transformation.
    • Carbon atoms colored blue are reduced, and those colored red are oxidized.
    • Peracid epoxidation and addition of bromine oxidize both carbon atoms, so these are termed oxidation reactions.
  • Oxidation

    • The carbon atom of a carbonyl group has a relatively high oxidation state.
    • Useful tests for aldehydes, Tollens' test, Benedict's test & Fehling's test, take advantage of this ease of oxidation by using Ag(+) and Cu(2+) as oxidizing agents (oxidants).
    • The Fehling and Benedict tests use cupric cation as the oxidant.
    • This deep blue reagent is reduced to cuprous oxide, which precipitates as a red to yellow solid.
    • All these cation oxidations must be conducted under alkaline conditions.
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