Reactive oxygen species

Singlet oxygen is responsible for much of the physiological damage caused by reactive oxygen species, including nucleic acid modification through selective reaction with deoxyguanosine to form 8-hydroxydeoxyguanosine (8-OHdG). The lifetime of singlet oxygen is sufficiently long (4.4 microseconds in water ) to permit significant diffusion in cells and tissues. In the laboratory, singlet oxygen is usually generated in one of three ways: photochemically from dioxygen ( 3O 2) using a photosensitizing dye ( Figure 18.2.1), chemically by thermal decomposition of a peroxide or dioxetane, or by microwave discharge through an oxygen stream. Singlet oxygen can be directly detected by its characteristic weak chemiluminescence at 1270 nm. Hypericin Among the most efficient reagents for generating singlet oxygen is the photosensitizer hypericin ( Hypericum. This heat-stable dye exhibits a quantum yield for singlet oxygen generation in excess of 0.7, as well as high photostability, making it an important agent for both anticancer and antiviral research. Rose Bengal Diacetate Rose bengal diacetate ( It is an iodinated xanthene derivative that has been chemically modified by the introduction of acetate groups. These modifications inactivate both its fluorescence and photosensitization properties, while increasing its ability to cross cell membranes. Once inside a live cell, esterases remove the acetate groups, restoring rose bengal to its native structure. Its intracellular localization a...

‘Reactive oxygen species’ (ROS) is an umbrella term for an array of derivatives of molecular oxygen that occur as a normal attribute of aerobic life. Elevated formation of the different ROS leads to molecular damage, denoted as ‘oxidative distress’. Here we focus on ROS at physiological levels and their central role in redox signalling via different post-translational modifications, denoted as ‘oxidative eustress’. Two species, hydrogen peroxide (H 2O 2) and the superoxide anion radical (O 2 ·−), are key redox signalling agents generated under the control of growth factors and cytokines by more than 40 enzymes, prominently including NADPH oxidases and the mitochondrial electron transport chain. At the low physiological levels in the nanomolar range, H 2O 2 is the major agent signalling through specific protein targets, which engage in metabolic regulation and stress responses to support cellular adaptation to a changing environment and stress. In addition, several other reactive species are involved in redox signalling, for instance nitric oxide, hydrogen sulfide and oxidized lipids. Recent methodological advances permit the assessment of molecular interactions of specific ROS molecules with specific targets in redox signalling pathways. Accordingly, major advances have occurred in understanding the role of these oxidants in physiology and disease, including the nervous, cardiovascular and immune systems, skeletal muscle and metabolic regulation as well as ageing and cance...

• Review Article • 27 June 2022 Reactive oxygen species signalling in plant stress responses • ORCID: orcid.org/0000-0003-3192-7450 • ORCID: orcid.org/0000-0002-1256-9371 • ORCID: orcid.org/0000-0002-3094-688X • … • ORCID: orcid.org/0000-0002-3147-0860 Show authors Nature Reviews Molecular Cell Biology volume 23, pages 663–679 ( 2022) Reactive oxygen species (ROS) are key signalling molecules that enable cells to rapidly respond to different stimuli. In plants, ROS play a crucial role in abiotic and biotic stress sensing, integration of different environmental signals and activation of stress-response networks, thus contributing to the establishment of defence mechanisms and plant resilience. Recent advances in the study of ROS signalling in plants include the identification of ROS receptors and key regulatory hubs that connect ROS signalling with other important stress-response signal transduction pathways and hormones, as well as new roles for ROS in organelle-to-organelle and cell-to-cell signalling. Our understanding of how ROS are regulated in cells by balancing production, scavenging and transport has also increased. In this Review, we discuss these promising developments and how they might be used to increase plant resilience to environmental stress. Open Access articles citing this article. • • Jinlong Zhang • , Li Zhang • … Jinling Huang BMC Plant Biology Open Access 12 June 2023 • • Mohammad Mukarram • , M. Masroor A. Khan • … Francisco J. Corpas Scientific Repor...