(60)Co-γ irradiation affects the enzymatic antioxidant system of the citrus red mite Panonychus citri (Acari: Tetranychidae).

Ke Zhang,Qunfang Weng,Shaowen Zhu,Zhibin Li

doi:10.3390/molecules19056382

Abstract

Radio-(60Co), which emits γ rays, has been used worldwide in pest control. The aim of the present study was to analyze the effect of effective-low-power 60Co-γ irradiation on the enzymatic antioxidant system of the citrus red mite Panonychus citri. One day old female adults were exposed to 0.4 kGy 60Co-γ irradiation and on the, 6th h, 1st day, 2nd day, and 5th day post treatment, the mites were euthanized for biochemical analysis. The activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), phenoloxidase (PO) and acetylocholinesterase (AchE) were investigated. POD and CAT activities, as well as SOD were higher in the irradiated mites. We found that exposure to 60Co-γ radiation resulted in increased activities of SOD, CAT, POD and decreased AchE activity. When the recovery time lasted till the 5th day, the activities of POD and PO were significantly lower than the control, whereas the SOD, CAT and AchE activities returned to control levels. Cells possess protein repair pathways to rescue oxidized proteins and restore their functions, but if these repair processes fail, oxidized proteins may become cytotoxic. Our results confirm the hypothesis that low dosages of 60Co-γ irradiation increase the level of oxidative stress in P. citri adults in a short time, causing meanwhile damage and sterility. The results of this study also indicate that stress caused by exposure to irradiation could inhibit the cholinergic system in P. citri.

Highlights

In many organisms, with 60Co-γ irradiation free radicals in the body, such as singlet oxygen, hydrogen peroxide, hydroxyl radical and superoxide anion will increase
The change in superoxide dismutase (SOD) activity suggested that 60Co-γ irradiation induces superoxide radicals in P. citri adults
That is consistent with previous reports showing that high doses of irradiation suppress the activity of protective enzymes, such as SOD in normal cells [25,26]

Summary

Introduction

With 60Co-γ irradiation free radicals in the body, such as singlet oxygen, hydrogen peroxide, hydroxyl radical and superoxide anion will increase. The endogenous enzymatic antioxidant system is important to protect the organism against high concentrations of ROS This system is composed mainly by the enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidases (POD) [1,2]. The citrus red mite, Panonychus citri (Acari:Tetranychidae), is a worldwide citrus pest with more than 80 host plants such as citrus, rose, almond, pear, castor bean, and several broadleaf evergreen ornamentals [10,11] It has a short life cycle and high reproductivity. The purpose of this study was to examine the impact of irradiation at a general dose produced by a commercial device on the activities of a range of antioxidant enzymes in P. citri, trying to better understand the radiation mechanism of action that may be involved with the positive results of irradiation on sterility for pest control. The most important studies on mites are reviewed in the following paragraphs

Results and Discussion

Insects

Analysis of Antioxidant Enzyme Activities

Statistical Analysis

Conclusions