Using the enzymatic and non-enzymatic antioxidant defense system of the land snail Eobania vermiculata as biomarkers of terrestrial heavy metal pollution

2012 ◽  
Vol 84 ◽  
pp. 347-354 ◽  
Author(s):  
Nahla S. El-Shenawy ◽  
Amaal Mohammadden ◽  
Zahra Hessenan Al-Fahmie
2012 ◽  
Vol 2012 ◽  
pp. 1-37 ◽  
Author(s):  
Mohammad Anwar Hossain ◽  
Pukclai Piyatida ◽  
Jaime A. Teixeira da Silva ◽  
Masayuki Fujita

Heavy metal (HM) toxicity is one of the major abiotic stresses leading to hazardous effects in plants. A common consequence of HM toxicity is the excessive accumulation of reactive oxygen species (ROS) and methylglyoxal (MG), both of which can cause peroxidation of lipids, oxidation of protein, inactivation of enzymes, DNA damage and/or interact with other vital constituents of plant cells. Higher plants have evolved a sophisticated antioxidant defense system and a glyoxalase system to scavenge ROS and MG. In addition, HMs that enter the cell may be sequestered by amino acids, organic acids, glutathione (GSH), or by specific metal-binding ligands. Being a central molecule of both the antioxidant defense system and the glyoxalase system, GSH is involved in both direct and indirect control of ROS and MG and their reaction products in plant cells, thus protecting the plant from HM-induced oxidative damage. Recent plant molecular studies have shown that GSH by itself and its metabolizing enzymes—notably glutathione S-transferase, glutathione peroxidase, dehydroascorbate reductase, glutathione reductase, glyoxalase I and glyoxalase II—act additively and coordinately for efficient protection against ROS- and MG-induced damage in addition to detoxification, complexation, chelation and compartmentation of HMs. The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1575
Author(s):  
Muhammad Jawad Hassan ◽  
Muhammad Ali Raza ◽  
Sana Ur Rehman ◽  
Muhammad Ansar ◽  
Harun Gitari ◽  
...  

Heavy metal stress is a leading environmental issue reducing crop growth and productivity, particularly in arid and semi-arid agro-ecological zones. Cadmium (Cd), a non-redox heavy metal, can indirectly increase the production of reactive oxygen species (ROS), inducing cell death. A pot experiment was conducted to investigate the effects of different concentrations of Cd (0, 5, 25, 50, 100 µM) on physiological and biochemical parameters in two sorghum (Sorghum bicolor L.) cultivars: JS-2002 and Chakwal Sorghum. The results showed that various concentrations of Cd significantly increased the Cd uptake in both cultivars; however, the uptake was higher in JS-2002 compared to Chakwal Sorghum in leaf, stem and root. Regardless of the cultivars, there was a higher accumulation of the Cd in roots than in shoots. The Cd stress significantly reduced the growth and increased the electrolyte leakage (EL), hydrogen peroxide (H2O2) concentration and malondialdehyde (MDA) content in both cultivars, but the Chakwal Sorghum showed more pronounced oxidative damage than the JS-2002, as reflected by higher H2O2, MDA and EL. Moreover, Cd stress, particularly 50 µM and 100 µM, decreased the activity of different antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). However, the JS-2002 exhibited higher SOD, POD and CAT activities than the Chakwal Sorghum under different Cd-levels. These findings revealed that JS-2002 had a stronger Cd enrichment capacity and also exhibited a better tolerance to Cd stress due to its efficient antioxidant defense system than Chakwal Sorghum. The present study provides the available information about Cd enrichment and tolerance in S. bicolor, which is used as an important agricultural crop for livestock feed in arid and semi-arid regions.


The literature review summarizes the data on the classification and characteristics of the antioxidant defense system. This model combines a number of different substances. Each of the components of the antioxidant system acts in close connection with its other structural elements, harmoniously complements, and in many cases – enhances the action of each other. The functional basis of the system of antioxidant protection is formed by the glutathione system, the constituent elements of which are actually glutathione and enzymes that catalyze the reactions of its reverse transformation (oxidation ↔ reduction). Most researchers conventionally divide the system of antioxidant protection into enzymatic and non-enzymatic. The enzyme links of the antioxidant defense system include: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase and other enzymes. The non-enzymatic system includes fat-soluble vitamins A, E and K, water-soluble vitamins C and PP, biogenic amines, glutathione, carotenoids, ubiquinone, sterols. Both enzymatic and non-enzymatic antioxidant defense systems are present in the bloodstream. The activity of the enzymatic antioxidant system is very well regulated and depends on age, physiological condition, hormone dynamics, intensity of antioxidant enzyme synthesis, pH, presence of coenzymes, inhibitors, activators and other factors. The non-enzymatic part of the antioxidant system does not require as many regulators as the chemical itself - the antioxidant - reacts chemically with the radical. Only the reaction rate can change. The lungs are directly exposed to oxygen and oxidants of polluted air, they are most sensitive to oxidative damage, so they have an increased possibility of free radical reactions. Protection against the damaging effects of reactive oxygen species and free radicals is provided by anti-radical protective systems, especially the glutathione system and its enzymes. Numerous papers have obtained clinical and experimental data on the important role of free radical oxidation of lipids (FROL) and antioxidant systems (AOS) protection in the development of many diseases, including pulmonary tuberculosis (TB). The review presents modern views on the state of the system of lipid peroxidation (LPO) and antioxidant protection in TB. The main topic of the review is information on the generation of free radical compounds by different populations of leukocytes with further enhancement of LPO and secondary deepening of functional disorders. The article substantiates the feasibility of identifying LPO products as non-specific markers of aseptic inflammation in TB and the need to develop new generations of antioxidants. One of the universal mechanisms of damage to cell membranes is LPO, the excessive activation of which is normally prevented by factors of the antioxidant defense system. Membrane-bound enzymes involved in the formation of LPO products include lipoxy and cyclooxygenases. Lipoperoxidation processes change the structure and phospholipid composition of cell membranes, which negatively affects the cellular immune response due to damage to the mechanisms of information transfer from extracellular regulators to intracellular effector systems.


2018 ◽  
Vol 10 (11) ◽  
pp. 479
Author(s):  
Wander Luiz da S. Ataíde ◽  
Glauco André dos S. Nogueira ◽  
Ana Ecídia de A. Brito ◽  
Ellen Gleice da S. Lima ◽  
Juscelino Gonçalves Palheta ◽  
...  

Tachigali vulgaris is a pioneer species, colonizing marginal lands and roadsides, often initiates secondary succession in open areas by the intense germination of their seeds in the soil. The main components of the antioxidant defense system can be divided into enzyme found primarily intracellularly (superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione reductase, etc.) and small non-enzymatic molecules that can be divided into soluble in water (ascorbic acid, glutathione and bilirubin) and lipid soluble (α-tocopherol, β-carotene and lycopene). Plants were then separated into leaves and roots, wrapped in aluminum foil and stored in Ultrafreezer at -80 °C. To determine the enzymatic activity and biochemical analyzes, the plant material was first frozen in liquid nitrogen and subsequently lyophilized. The experimental design was completely randomized in a factorial 3 × 2 (three times: zero, five and ten days of water suspension, and two water conditions: control and drought stress), with four repetitions. Analysis of variance was applied to the results and when significant difference, the means were compared using the t test adopting the 5% level of probability through the statistical package (7.7 beta Assistat, 2015). Since they were able to drive quickly the enzymatic antioxidant defense system (SOD, CAT and APX), however, failing to reduce oxidative damage resulting in the death of them.


2009 ◽  
Vol 25 (6) ◽  
pp. 411-416 ◽  
Author(s):  
N Gumral ◽  
S Calıskan ◽  
F Ozgüner ◽  
S Kaleli ◽  
A Akkaya ◽  
...  

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