Reactive Oxygen Species

Introduction

The increasing concentration of oxygen level in the atmosphere near about 2.5 billion ago, oxygenic photosynthesis by cyanobacteria leads to the evolution of aerobic respiration leading to the development of complex eukaryotic organisms. All the aerobic organisms depends upon the cellular respiration and some of the derivatives of oxygen are highly toxic for the cells. Reactive oxygen species, reactive oxygen intermediates and reactive nitrogen species have been used to define the highly reactive oxygen bearing molecules. Hydroxyl and peroxyl radicals, hydrogen peroxide and superoxide radical anions are some of the species responsible for the damage of the fatty acids, DNA and proteins as well as other cellular components. The redox reaction is typically involved in controlling production of reactive oxygen and nitrogen species. They can, in turn, react with specific functional group of target proteins like clusters, cysteines etc. that lead to covalent protein modifications. ROS as as second messengers are important for the expression of several transcription factors and other signal transduction molecules such as het shock inducing factor and nuclear factor. They also participate in the regulation of cell adhesion, redox-mediated amplifications of immune response and programmed cell death1. Reactive oxygen species was once thought to be originated entirely from the metabolism of mitochondria. Normally during the metabolism process in mitochondria the final oxygen receptor is reduced to water and in some pathological process the electron might leak out of the system prematurely into the surrounding leading to ROS formation. However it has been seen after study that cellular enzyme like NADPH oxidase are an important source of ROS in humans. After repeated study it has been seen that the isoforms of NADPH plays an important role in tissue localization, mechanism of activation and role in pathologies. By this it become evident that ROS might have taken part in cell to cell signaling in unicellular organisms and they developed ways to use ROS in critical physiological purposes. ROS plays a significant role in growth, apoptosis and cellular signaling and systematically the ROS are responsible in the complex functions of regulating blood pressure, cognitive and immune function and are one of the responsible factors for the killing of pathogens 2. Oxidative stress are some of the relevant facors that are responsible for the imbalance between the ROS production and anti-oxidant defenses and leads to the formation of several pathological conditions like Alzheimer’s disease, Dementia, cardiovascular disease, inflammatory problems and neurodegenerative conditions 3.

Source:-

1. Krumova K, Cosa G, Volume 1 2016, Overview of Reactive Oxygen Species, Royal Society of Chemistry, SBN 978-1-78262-220-8,

https://pubs.rsc.org/en/content/chapterhtml/2016/bk9781782620389-00001?isbn=978-1-78262-038-9.

2. Brieger K, Schiavone S, Miller F, Reactive oxygen species from health to disease, Research Gate, 2012

https://www.researchgate.net/publication/230698698_Reactive_oxygen_species_From_health_to_disease.

3.Krumova K, Cosa G, Volume 1 2016, Overview of Reactive Oxygen Species, Royal Society of Chemistry, SBN 978-1-78262-220-8,

https://pubs.rsc.org/en/content/chapterhtml/2016/bk9781782620389-00001?isbn=978-1-78262-038-9

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