The effect of nitrobenzene on antioxidative enzyme activity and DNA damage in tobacco seedling leaf cells

Abstract

Nitrobenzene, although widely used in industry, is a highly toxic environmental pollutant. To evaluate the toxicity of nitrobenzene to tobacco seedlings, seedlings were exposed to varying concentrations of nitrobenzene (0-100 mg/L) for 24 h. The contents of reactive oxygen species (hydrogen peroxide [H(2)O(2)] and superoxide anion [O2(-)]) and the activities of antioxidative enzymes (superoxide dismutase [SOD], guaiacol peroxidase [POD], and catalase [CAT]) were measured in leaf cells. Damage to DNA was assessed by single-cell gel electrophoresis (comet assay). Compared with the control, the contents of H(2) O(2) increased significantly with nitrobenzene concentrations ranging from 5 to 100 mg/L. Activity of SOD was induced by 50 to 100 mg/L of nitrobenzene but not by 10 to 25 mg/L. Activity of POD was stimulated by nitrobenzene at 10 to 50 mg/L but inhibited at 100 mg/L. Activity of CAT was increased significantly only by 100 mg/L. Lipid peroxidation increased with 50 to 100 mg/L, which indicated that nitrobenzene induced oxidative stress in tobacco leaf cells. Comet assay of the leaf cells showed a significant enhancement of the head DNA (H-DNA), tail DNA (T-DNA), and olive tail moment (OTM) with increasing doses of nitrobenzene. The values of H-DNA, T-DNA, and OTM exhibited significant differences from the control when stress concentrations were higher than 10 mg/L. The results indicated that nitrobenzene caused oxidative stress, which may be one of the mechanisms through which nitrobenzene induces DNA damage.

Varietal differences in the growth of rice seedlings exposed to perchlorate and their antioxidative defense mechanisms

“…might cause little membrane damage on gannuoxiang plants. Elevating SOD, POD, and CAT increased the formation of ROS in the cell, detoxified during peroxidase and catalase reactions [27,35]. The results of the present study indicate that gannuoxiang has higher activities of antioxidant enzymes to mitigate oxidative stress when ClO 4…”

“…Superoxide dismutase and CAT activities decreased, but the contents of MDA increased in IR65598‐112‐2 at higher concentrations of ClO 4 – , but not in gannuoxiang. Increased SOD activity might indicate that increased superoxide radical concentration led to stimulation of the biosynthesis of SOD and that SOD could efficiently convert O 2 – into O 2 or H 2 O 2 ; decreased SOD activity might indicate inactivation of the enzyme by H 2 O 2 . Increased POD activity indicated that exposure to ClO 4 – induced the formation of H 2 O 2 , which in turn stimulated the biosynthesis of POD.…”

“…Abiotic stresses such as drought and salinity affect plants via various mechanisms, inducing osmotic stress, ionic imbalance, and DNA damage, as well as oxidative stress [26][27][28]. The presence of high concentrations of reactive oxygen species (ROS) can lead to serious oxidative stress to plant cells.…”

Transcriptome analysis of alfalfa (Medicago sativa L.) roots reveals overwintering changes in different varieties

“…We used 0.1 g of fresh roots, homogenised them in 1.5 mL of a potassium phosphate buffer (50 mM, pH 7.0) and centrifuged them at 12 000 rpm for 20 min at 4 °C to obtain the supernatants for the antioxidant activity. The superoxide dismutase (SOD) activity was determined by autoxidation with o-triol (Paoletti & Mocali 1990) and the perosuperoxide dismutasexidase (POD) activity was determined using guaiacol oxidation (Si et al 2012). The experiment was repeated three times for each group.…”