Cell and Tissue Journal

Abstract Aim: Nanoparticles are superior to conventional elemental forms due to the novel physicochemical properties that enable them to act as plant growth promoters. Recent research on nanomaterials has been shown both positive and negative effects. Titanium dioxide nanoparticles (TiO₂ NPs) are assayed worldwide in large quantities for various purposes. This study investigated the effect of TiO₂ NPs on some physiological and biochemical traits and the induction of the antioxidant systems in Origanum vulgare L. and Origanum majorana L., in a completely randomized design with three repetitions.
Material and Methods: Surface-sterilized seeds were sown with 2 cm depth in each plastic pots filled with a 1: 1 mix of loamy soil and sand. Until reaching the appropriate physiological age, they were exposed to greenhouse conditions (16 h light/8 h dark photoperiod). Two-month-old plants were foliar sprayed with 10, 60, and 120 mg/L TiO₂ NPs and harvested 14 days after the last treatment. Plants sprayed with distilled water were used as controls. Changes in the photosynthetic pigments (the content of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), biochemical properties (the levels of membrane stability index, malondialdehyde, and proline contents), and the activity of antioxidant enzymes (Guaiacol peroxidase, ascorbate peroxidase, polyphenol oxidase, superoxide dismutase, catalase, and glutathione s-transferase) were measured in the collected samples.
Results: The comparison of data means showed that the treatment of 60 mg/L TiO₂ NPs caused the maximum amount of chlorophyll a, total chlorophyll, and carotenoids in both Origanum species. However, the highest content of chlorophyll b in O. majorana was observed in the treatment of 120 mg/L TiO₂ NPs. It is worth mentioning that the negative effect of the concentration of 120 mg/L TiO₂ NPs on the membrane system of two species is statistically significant and remarkable due to the leakage of electrolytes. Although the increase in the concentration of TiO₂ NPs led to fewer levels of malondialdehyde in O. vulgare in comparison with O. majorana; this concentration was found to be effective to the high levels of proline in O. vulgare. Most of the antioxidant enzymes (Guaiacol peroxidase, ascorbate peroxidase, polyphenol oxidase, superoxide dismutase, and glutathione s-transferase) of O. vulgare showed their maximum activity at the concentration of 60 mg/L TiO₂ NPs. However, the lower activity of catalase in O. vulgare, compared to O. majorana was remarkable.
Conclusion: The results of this research show that the treatment of 60 mg/L TiO₂ NPs improves the physiological characteristics of the medicinal plant Origanum, including the increase of photosynthetic pigments, followed by the rate of photosynthesis and the increase of biomass. It is noteworthy that higher levels than the optimal concentrations of TiO₂ NPs can lead to an increase in the levels of ROS and oxidative burst, which leads to a decrease in plant performance. Therefore, the plant response to nanoparticles depends significantly on the concentration and time of application, as well as the size, shape, and surface functionalization of the particles. Finally, O. vulgare is introduced as a more successful species due to the higher activity of antioxidant enzymes when treating TiO₂ NPs.

Abstract Aim: This study was investigated, the effect of foliar application of different levels of putrescine on physiological, biochemical traits, and essential oil content of Mexican marigold (Tagetes minuta L.) under drought stress.
Material and Methods: The experiment was conducted as a factorial experiment in a completely randomized design with three replications in greenhouse conditions. The first factor was drought stress at three levels (75, 50, and 25% of field capacity) and the second factor was putrescine foliar application at four levels (0, 0.5, 1, and 2 mM). Four seedlings were planted in each pot. Stress was applied when the plants reached a height of about 25 cm. Putrescine was sprayed one week before flowering and every 7 days until the 80% flowering stage.
Results: The results showed that 2 mM foliar application of putrescine was more effective than other concentrations and was able to greatly reduce the harmful effects of drought stress on this plant. With the increasing drought, antioxidant activity, total phenol, proline, and electrolyte leakage also increased, and in contrast, the relative content of leaf water, photosynthetic pigments, and soluble protein decreased. Drought also increased the activity of the antioxidant enzymes guaiacol peroxidase (GPX) and polyphenol oxidase (PPO) and the amount of malondialdehyde in this plant. With increasing drought stress up to 50% of field capacity and foliar application of 1 mM putrescine, the essential oil content of Mexican marigold increased, while under severe stress (25% of field capacity) is decreased. Putrescine decreased by inducing drought resistance. The activity of antioxidant enzymes and the amount of malondialdehyde.
Conclusion: The use of putrescine induced resistance to drought stress in Mexican marigold, and the use of a concentration of 2 mM can be effective and recommended.
 
 
 

Abstract Aim: The present study aims to investigate if artesunate exerts its anti-proliferative activity by increasing antioxidant enzymes activity in MCF-7 human breast cancer cell line. Determining the oxidant effect of artesunate may elucidate a possible alternative mechanism for its cytotoxicity. Material and methods: For evaluating cytotoxic activity of artesunate, MCF-7 cells were treated with different concentrations (0, 1, 5, 10, 25, 50, 75, 100 and 200 μg/ml) of artesunate and subjected to MTT assay after 24 hours. Also, the enzymatic activities of superoxide dismutase (SOD), and peroxidase (POD) were measured in MCF-7 cells treated with selected doses of artesunate (0, 10, 25, 50 and 100 μg/ml) after 24h. In addition, the cell culture supernatants were used to assess the amount of nitric oxide (NO) production using the Griess method. Results: Artesunate inhibited the growth of MCF-7 cells, dose-dependently and also significantly increased the activity of antioxidant enzymes: superoxide dismutase (SOD), and peroxidase (POD). Furthermore, it suppressed NO production, dose-dependently. Conclusion: To conclude, it seems that artesunate exert its cytotoxic activity by increasing the activity of antioxidant enzymes and through inhibition of NO production in MCF-7 cells. The increased activities of antioxidant enzymes in the treated cells could alter the antioxidant defense system, potentially contributing towards the anti-proliferative effect.

Abstract Aim: The purpose of the present research project was evaluation of the effect of silicon on the severity of peroxidase genes expression and some morphological traits in both resistant and susceptible barley lines under drought stress. Material and Methods: Total soluble protein content, photosynthetic pigments, and total RNA were extracted from the leaves affected by various treatments. Target gene was evaluated by Semi-quantitative RT-PCR analysis using synthesized cDNA. Both the peroxidase enzyme activity by Chance method and proline with Bates method were also evaluated under drought stress treatment. Accordingly, the experiment was analyzed in a factorial test based on the completely randomized design with three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 Kg soil) with three replications in a greenhouse. Results: Silicon application caused to increase the amount of total soluble protein and photosynthetic pigments in both lines under drought stress. Semi-quantitative RT-PCR analysis of treatments observed significant differences. Maximum of peroxidase gene expression was observed in the silicon-drought treatment. Antioxidant enzyme activities were at the highest level as shown by gene expression pattern of polyacrylamide gel analysis for treated silicon samples. A further increase was exhibited for proline accumulation caused by silicon application rather than such accumulation in stress treatment compared to control. Conclusion: Silicon reduces oxidative damage induced by reactive oxygen species and with the increase in antioxidant enzyme activities caused to protect plants against environmental stresses.  

Abstract Aim: In this study, sodium nitroprusside effect as a producer of NO on growth, antioxidant enzyme activities and some physiological parameters in in vitro cultured Melissa officinalis seedlings were studied.
Material and methods: After establishment of Melissa officinalis seedling culture, seedlings were treated with different concentrations of sodium nitroprusside (0, 25, 50 and 100 µM). Then, they were harvested for growth, protein content, secondary metabolites, lipid peroxidation level and antioxidant enzymes activities analysis after 10 days.
Results: Results showed that growth and protein content decreased with increasing concentration of sodium nitroprusside. Phenolic compounds amount, total flavonoids and anthocyanins increased by sodium nitroprusside. Also Malondialdehyde content as lipid peroxidation product was significantly increased. In response to oxidative stress, chatalase and peroxidase enzymes activities were respectively increased at 50 and 25 µM sodium nitroprusside while enzymes activities showed decreasing at 100 µM.
 Conclusion: Overall, the results indicate that sodium nitroprusside as NO producer damage the cell membrane. Therefore reduced Melissa officinalis seedling growth and caused oxidative stress in them. To overcome produced free radical, secondary metabolites amounts and antioxidant enzymes activities were increased.