A Review on
oxidative burst: Biochemical
implications of metal toxicity
Darshan Malik1, Sunita Singh1,
Jayita Thakur1, Amarjeet Kaur2,
S Nijhawan1
1Department of
Biochemistry, Shivaji College, University of Delhi, New Delhi, India
2Guru Gobind Singh
Indraprastha University, Dwarka, New Delhi, India
Received: 20 September 2016 Revised
Accepted: 15 November 2016
ABSTRACT
The
bioaccumulation and biomagnifications of metals is a source of great concern
for the living systems. A wide range of heavy metals which are the essential
micronutrients for plants and animals exhibit toxic effects at higher levels
via metabolic interference and mutagenesis. The metals are reported to enter
the bio geo chemical cycle via atmosphere, soil erosion and through high anthropogenic activities and cause toxicity in
plants, fishes and animals. Heavy metals like Lead (Pb), Cadmium (Cd), Chromium
(Cr), Arsenic (As) and Nickel (Ni) cause enhanced production of Reactive Oxygen
Species (ROS) such as .O2
, H2O2, and .OH
radicals. The increased generation of ROS cause "oxidative burst" in
the system. Cells under oxidative stress display various dysfunctions due to
lesions caused by ROS to lipids, proteins and DNA. Accumulation of heavy metals
in the system result in abiotic stress leading to the induction of the
antioxidant defense-related secondary metabolites viz. phytochelatin
(PC), ascorbate, glutathione (GSH), anthocyanin and carotenoids. Various steps can be employed to counteract the stress
induced by increased levels of heavy metals. Chelation therapy has
emerged as an effective treatment against reducing metal toxicity in animals by
using chelating agents like Calcium Disodium Ethylene Diamine Tetra Acetic Acid
(CaNa2EDTA), British Anti Lewisite (BAL) and Mono methyl Meso 2,
3-Dimercaptosuccinic Acid (MmDMSA). Metal toxicity in the environment
can be managed by using hyper accumulating plant species belonging to the
family of Brassicaceae, Solanaceae and Crassulaceae for phytoremediation and phytomining. This review is a
comparative analysis of the effects of heavy metal toxicity on various
physiological and biochemical processes of both plants and animals as well as
methods to counteract them.
Key Words: Apoptosis,
Cellular toxicity, Chelation therapy, Fenton reaction, Glutathione, Heavy
metals, Oxidative burst, Phytoremediation, Phytomining, Reactive oxygen
species, Signal transduction