Effect of CO2 Laser Radiation on Physiological Tolerance of Wheat Seedlings Exposed to Chilling Stress

To determine the effect of CO₂ laser pretreatment of wheat seeds on the physiological tolerance of seedlings to chilling stress, wheat seeds were exposed to CO₂ laser radiation for 300 s. After being cultivated for 48 h at 25°C, the wheat seedlings were subjected to chilling stress for 24 h. Selected physiological and biochemical parameters were measured in 6-day-old seedlings. We observed that chilling stress enhanced the concentrations of malondialdehyde and oxidized glutathione while decreasing the activities of nitric oxide synthase, catalase, peroxidase, superoxide dismutase and the concentrations of nitric oxide and glutathione in the wheat leaves compared with controls. When the chilling stress was preceded by CO₂ laser irradiation, the concentrations of malondialdehyde and oxidized glutathione were decreased while the activities of nitric oxide synthase, catalase, peroxidase, superoxide dismutase and the concentrations of nitric oxide and glutathione increased. Furthermore, chilling stress decreased the biomass, biophoton intensity and GHS/GSSG ratios of seedlings while these parameters increased when the seedlings were treated with CO₂ laser irradiation prior to the chilling stress. The results suggest that a suitable dose of CO₂ laser stimulation can enhance the physiological tolerance of wheat seedlings to chilling stress.     

Laser pretreatment protects cells of broad bean from UV-B radiation damage

In order to determine the role of lasers in the stress resistance of broad bean (Vicia faba L.) to ultraviolet-B (UV-B) radiation, the embryos in seeds were exposed to He-Ne laser or CO2 laser radiation. Afterwards they were cultivated in Petri dishes in a constant temperature incubator until the lengths of epicotyls were nearly 3 cm. The epicotyls were then exposed to 1.02, 3.03 or 4.52 kJ m(-2) UV-B radiation, respectively, under 70 micromol m(-2) s(-1) photosynthetically active radiation (PAR) in a growth cabinet. Changes in the concentration of malondialdehyde (MDA), ascorbic acid (AsA) and UV-B absorbing compounds (absorbance at 300 nm) were measured to test the effects of laser pretreatment. The results showed that laser pretreatment of embryos enhanced UV-B stress resistance in the epicotyls of the broad bean by decreasing the MDA concentration and increasing the content of AsA and UV-B absorbing compounds. We suggest that those changes in MDA, AsA and UV-B absorbing compounds were responsible for the increase in stress resistance observed in the broad bean. This is the first investigation reporting the use of laser pretreatment to protect the cells of the broad bean from UV-B-induced damage.     

Microwave treatment of eight seconds protects cells of Isatis indigotica from enhanced UV-B radiation lesions

To determine the role of microwaves in the stress resistance of plants to enhanced ultraviolet-B (UV-B) radiation, Isatis indigotica Fort. seeds were subjected to microwave radiation for 8 s (wavelength 125 mm, power density 1.26 mW mm(-2), 2450 MHz). Afterwards they were cultivated in plastic pots in an artificial-glass greenhouse maintained at 25 degrees C, 70% relative humidity, and 400 micromol mol(-1) CO2, under visible-light conditions of 1500 micromol m(-2) s(-1) for 8 h day(-1). When the seedlings were 10 days old, they were subjected to 10.08 kJ m(-2) UV-B (PAR: 220 micromol m(-2) s(-1)) radiation for 8 days. Changes in a number of physiological and biochemical characteristics and in the thermal decomposition enthalpy of biomass were measured and used as indicators of the protective capacity of microwave radiation in this experiment. Our results revealed that microwave pretreatment of seeds enhanced UV-B stress resistance in the seedlings by decreasing the concentration of malondialdehyde (MDA) and increasing the concentration of ascorbic acid (AsA) and UV-B-absorbing compounds, increasing the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), and increasing the energy accumulation of photosynthesis. All these results suggest that microwave radiation enhances plant metabolism and results in increased UV-B stress resistance. This is the first investigation reporting the use of microwave pretreatment to protect the cells of Isatis indigotica from UV-B-induced lesions.     

Effect of paclobutrazol on water stress amelioration through antioxidants and free radical scavenging enzymes in Arachis hypogaea L

An investigation was carried out to find out the extent of changes occurred in groundnut (Arachis hypogaea L.) cultivars in response to paclobutrazol (PBZ) treatment under water deficit stress. Two groundnut cultivars namely ICG 221 and ICG 476 were used for the study. Individual treatment with PBZ and drought stress showed an increase in ascorbic acid, -tocopherol and reduced glutathione, superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) activities. PBZ with drought stressed plants maintained higher levels of antioxidant and scavenging enzymes. Significant differences were observed between cultivars and treatments. These results suggests that the adverse effects of water stress can be minimized by the application of PBZ by increasing the antioxidant levels and activities of scavenging enzymes such as SOD, APX and CAT. The Cv. ICG 221 appears to be more tolerant to water stress than the ICG 476.     

Effects of Vitamin E on the Activities of Protective Enzymes and Membrane Lipid Peroxidation in Leymus Chinensis under Drought Stress

Leymus chinensis seedlings were treated with 0.05--10 mmol/L vitamin E under osmotic stress in the presence of polyethylene glycol（PEG） as the stress reagent. The effects of the different concentrations of exogenous vitamin E on the activities of SOD, POD and free proline, and the MDA contents under drought stress were examined so as to ascertain the mechanism of Leymus chinensis resistance to drought stress and explore the possible preventive measures. The results indicate that the activities of SOD and POD decreased but the free proline and MDA contents increased as drought stress was accentuated, showing an enhancement of oxidative stress that may cause a decline in membrane stabilization. However, the activities of SOD and POD and the free proline content increased, whereas the MDA content reduced in Leymus chinensis pretreated with vitamin E in comparison with that of the control. This indicates that exogenous vitamin E enhanced the antioxidation of Leymus chinensis seedlings. It suggests that cytomembrane can be protected from damage by increasing the free proline content and the activities of SOD and POD that result in enhancing the drought resistance of Leymus chinensis seedlings.     

Antioxidant Effect of Selenium-containing Glutathione S-Transferase in Rat Cardiomyocytes

As one of the most important antioxidant enzymes, glutathione peroxidase(GPX) protects cells and tissues from oxidative damage, and plays an important role in cardiovascular and cerebrovascular injuries induced by oxidative stress. The antioxidant effect of selenium-containing glutathione S-transferase(Se-GST), a mimic of GPX was investigated on rat cardiomyocytes. To explore the protection function of Se-GST in hydrogen peroxide(H₂O₂) challenged rat cardiomyocytes, we examined malondialdehyde(MDA), lactate dehydrogenase(LDH), superoxide dismutase( SOD) and cell apoptosis. The results demonstrate exposure of rat cardiomyocytes to H₂O₂ for 6 and 12 h induced the significant increases of MDA, LDH and apoptosis rate of cardiomyocytes, but pretreatment of rat cardiomyocytes with Se-GST at 0.0005 or 0.001 unit/mL prevents oxidative stress induced by H₂O₂ with the decreases of cell apoptosis. All the results hint Se-GST has antioxidant activity for oxidative stress challenged rat cardiomyocytes.     

The Antioxidant Effect of Curcumin and Rutin on Oxidative Stress Biomarkers in Experimentally Induced Periodontitis in Hyperglycemic Wistar Rats

Background: There is a growing interest in the correlation between antioxidants and periodontal disease. In this study, we aimed to investigate the effect of oxidative stress and the impact of two antioxidants, curcumin and rutin, respectively, in the etiopathology of experimentally induced periodontitis in diabetic rats. Methods: Fifty Wistar albino rats were randomly divided into five groups and were induced with diabetes mellitus and periodontitis: (1) (CONTROL)—control group, (2) (DPP)—experimentally induced diabetes mellitus and periodontitis, (3) (DPC)—experimentally induced diabetes mellitus and periodontitis treated with curcumin (C), (4) (DPR)—experimentally induced diabetes mellitus and periodontitis treated with rutin (R) and (5) (DPCR)—experimentally induced diabetes mellitus and periodontitis treated with C and R. We evaluated malondialdehyde (MDA) as a biomarker of oxidative stress and reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG and catalase (CAT) as biomarkers of the antioxidant capacity in blood harvested from the animals we tested. The MDA levels and CAT activities were also evaluated in the gingival tissue. Results: The control group effect was statistically significantly different from any other groups, regardless of whether or not the treatment was applied. There was also a significant difference between the untreated group and the three treatment groups for variables MDA, GSH, GSSG, GSH/GSSG and CAT. There was no significant difference in the mean effect for the MDA, GSH, GSSG, GSH/GSSG and CAT variables in the treated groups of rats with curcumin, rutin and the combination of curcumin and rutin. Conclusions: The oral administration of curcumin and rutin, single or combined, could reduce the oxidative stress and enhance the antioxidant status in hyperglycemic periodontitis rats.     

Neuroprotective activity of lavender oil on transient focal cerebral ischemia in mice

The air-dried aerial parts of Lavandula angustifolia Mill, a traditional Uygur herbal drug, is used as resuscitation-inducing therapy to treat neurodisfunctions, such as stroke. This study was designed to assess the neuroprotective effects of lavender oil against ischemia/reperfusion (IR) injury in mice. Focal cerebral ischemia was induced by the intraluminal occlusion method with a nylon string. The neurodysfuntion was evaluated by neurological deficit and the infarct area was showed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The histopathological changes were observed by hematoxylin and eosin staining. The levels of mitochondria-generated reactive oxygen species (ROS), malondialdehyde (MDA) and carbonyl, the ratio of reduced glutathione (GSH)/glutathione disulfide (GSSG), the activities of superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GSH-Px) in brain tissue were measured to estimate the oxidative stress state. Neurological deficit, infarct size, histopathology changes and oxidative stress markers were evaluated after 22 h of reperfusion. In comparison with the model group, treatment with lavender oil significantly decreased neurological deficit scores, infarct size, the levels of MDA, carbonyl and ROS, and attenuated neuronal damage, upregulated SOD, CAT, GSH-Px activities and GSH/GSSG ratio. These results suggested that the neuroprotective effects of lavender oil against cerebral ischemia/reperfusion injury may be attributed to its antioxidant effects.     

Changes of antioxidative enzymes and cell membrane osmosis in tomato colonized by arbuscular Mycorrhizae under NaCl stress

Salinity toxicity is a worldwide agricultural and eco-environmental problem. Many literatures show that arbuscular mycorrhizal fungi (AMF) can enhance salt tolerance of many plants and some physiological changes occurred in AM symbiosis under salt stress. However, the role of ROS-scavenging enzymes in AM tomato is still unknown in continuous salt stress. This study investigated the effect of Glomus mosseae on tomato growth, cell membrane osmosis and examined the antioxidants (superoxide-dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; peroxidase, POD) responses in roots of mycorrhizal tomato and control under different NaCl stress for 40 days in potted culture. NaCl solution (0, 0.5 and 1%) was added to organic soil in the irrigation water after 45 days inoculated by AMF (Glomus mosseae). (1) AMF inoculation improved tomato growth under salt or saltless condition and reduced cell membrane osmosis, MDA (malonaldehyde) content in salinity. So the salt tolerance of tomato was enhanced by AMF; (2) SOD, APX and POD activity in roots of AM symbiosis were significantly higher than corresponding non-AM plants in salinity or saltless condition. However, CAT activity was transiently induced by AMF and then suppressed to a level similar with non-AM seedlings; (3) higher salinity (1% level) and long stress time suppressed the effect of AMF on SOD, APX, POD and CAT activity; (4) this research suggested that the enhanced salt tolerance in AM symbiosis was mainly related with the elevated SOD, POD and APX activity by AMF which degraded more reactive oxygen species and so alleviated the cell membrane damages under salt stress. Whereas, the elevated SOD, POD and APX activity due to AMF depended on salinity environment.     

Osmotic regulation of 10 wheat (Triticum aestivum L.) genotypes at soil water deficits

Drought is a worldwide problem, seriously influencing plant (crop) productivity. Wheat is a stable food for 35% of the world population, moreover about 60% of land area on the globe belongs to arid and semi-arid zone. Wheat drought resistance is a multi-gene-controlling quantitative character and wheat final production in field is realized mainly by physiological regulation under the condition of multi-environmental factor interaction. Exploring drought resistance physiological mechanisms for different wheat genotypes is of importance to finding new drought resistance gene resources and conventional breeding and the basis for wheat drought resistance biotechnological breeding and platform. Osmotic adjustment regulation is the main component for physiological machinery of wheat drought resistance. By pot-cultivating experiments, investigation of osmotic adjustment comparison for 10 wheat genotypes at soil water deficits (75% FC, 55% FC, 45% FC, respectively), was conducted. The main results were as followed: (1) K⁺ content in 10 wheat genotypes at three levels of soil water stress and at the same soil water deficit was very different. Five of these 10 wheat genotypes had higher K K⁺ content under the condition of 75% FC. (2) Five of these 10 wheat genotypes possessed greater soluble sugar content at 55% FC soil water level. (3) Proline (Pro) content in five wheat genotypes was higher at 75% FC. (4) Five of these 10 wheat genotypes had lower malondialdehyde (MDA) content at 45% FC at seedling stage. Osmotic adjustment of wheat different genotypes was discussed in terms of different content of osmotic solutes.     

Potential of <Emphasis Type="Italic">Crocus sativus</Emphasis> (saffron) and its Constituent,Crocin, as Hypolipidemic and Antioxidant in Rats

The aim of the present study was to evaluate the hypolipidemic and antioxidant potential of saffron and its active constituent, crocin, in hyperlipidemic rats. The animals fed either with normal fat diet or high fat diet were administered orally saffron (25, 50, and 100 mg/kg) or crocin (4.84, 9.69, and 19.38 mg/kg) in their respective groups for five consecutive days. Biochemical estimations of triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), alkaline phosphatase (ALP), aspartate transaminase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA), glutathione peroxidase enzyme activity (GSHPx), total glutathione (GSH), and oxidized glutathione (GSSG) in serum and superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive species (TBARS), ferric reducing/antioxidant power (FRAP), and total sulfhydryl (SH) groups in liver tissue homogenate were carried out. Both saffron and crocin were effective in decreasing the elevated levels of TG, TC, ALP, AST, ALT, MDA, GSHPx, GSH, and GSSG in serum and increasing SOD, CAT, FRAP, and SH values in liver tissue with reduction in TBARS. The saffron was found to be superior to crocin indicating the involvement of other potential constituents of saffron apart from crocin for its synergistic behavior of quenching the free radicals and ameliorating the damages of hyperlipidemia.     

Changes in antioxidant metabolism of Vigna unguiculata (L.) Walp. by propiconazole under water deficit stress

In the present study, a pot culture experiment was conducted to estimate the ameliorating effect of propiconazole (PCZ) on drought stress in cowpea (Vigna unguiculata (L.) Walp.) plants. From 30 days after sowing (DAS), the plants were subjected to 3, 6 and 9 days interval drought (DID) stress and drought stress with PCZ at 15 and 15 mg l(-1) PCZ alone and 1 day interval irrigation was kept as control. The plant samples were collected on 34 DAS (3 DID), 37 DAS (6 DID) and 40 DAS (9 DID). The plants were separated into root, stem and leaf for estimating the antioxidant contents and activities of antioxidant enzymes. Individual and combined drought stress and PCZ treatments increased ascorbic acid (AA), alpha-tocopherol (alpha-toc) contents, superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and polyphenol oxidase (PPO) activities when compared to control. The PCZ treatment mitigated the adverse effects of drought stress by increasing the antioxidant potentials and thereby paved the way for overcoming drought stress in V. unguiculata plants.     

Effect of sound wave stress on antioxidant enzyme activities and lipid peroxidation of Dendrobium candidum

The effect of sound wave stress on important medicinal plant, Dendrobium candidum Wall. ex Lindl, was investigated, including the responses on malondialdehyde (MDA) content, the activities change of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). Results were found that the activities of SOD, CAT, POD and APX enhanced totally in different organs of D. candidum, as leaves, stems and roots, in response to the stress. Furthermore there happened similar shift of antioxidant enzymes activities, which increased in the initial stimulation and decreased afterwards. Data showed SOD, CAT, POD and APX activities ascended to max at day 9, 6, 9 and 12 in leaves, at day 9, 6, 12 and 9 in stems, and at day 12, 6, 9 and 9 in roots, respectively. As a lipid peroxidation parameter, MDA content in different organs increased in the beginning, dropped afterward, and increased again in the late. Anyway the total trend was the rise of MDA level compared to the control. It was interesting that the MDA content appeared the lowest levels almost when the antioxidant enzymes activities were up to the highest. Our results demonstrated the different organs of D. candidum might produce accumulation of active oxygen species (AOS) under initial treatment of sound wave stress. Later AOS might start to reduce due to the enhancement of antioxidant enzymes activities treated by the stress. The data revealed that the antioxidant metabolism was to be important in determining the ability of plants to survive in sound stress, and the up regulation of these enzymes activities would help to reduce the build up of AOS, which could protect plant cells from oxidative damage. Moreover, different cell compartments might activate different defensive system to reduce excessive amount of AOS. Finally the mechanism of this action was also discussed simply.     

硝普钠对镧胁迫下黑麦草幼苗叶片碳氮代谢和抗氧化系统的影响

为了探讨一氧化氮(NO)对镧胁迫下牧草生理响应的调节作用,采用水培方法,研究了NO供体硝普钠(SNP)对300μmol.L-1LaCl3胁迫下黑麦草幼苗生长、碳氮代谢和抗氧化系统的影响。结果表明:LaCl3胁迫下,喷施50μmol.L-1SNP能显著缓解幼苗生物量的下降,提高叶片超氧化物歧化酶和抗坏血酸过氧化物酶活性,降低超氧阴离子(O2.-)产生速率及H2O2和丙二醛含量;促进可溶性糖和可溶性蛋白质积累,提高二磷酸核酮糖羧化酶、磷酸烯醇式丙酮酸羧化酶、内肽酶和羧肽酶活性。表明NO可通过提高活性氧清除能力,维持碳氮代谢正常运转,从而缓解LaCl3胁迫对黑麦草生长的抑制作用。     

Protective effect of total flavonoids from Spirodela polyrrhiza (L.) Schleid on human umbilical vein endothelial cell damage induced by hydrogen peroxide

In this study, we determined the protective effect of total flavonoids from Spirodela polyrrhiza (L.) Schleid (STF), which is a kind of traditional Chinese medicine, on human umbilical vein endothelial cells (ECV-304) damage induced by hydrogen peroxide (H(2)O(2)). Treated with 1mmol/L H(2)O(2) for 1h, the viability of ECV-304 cells markedly decreased. However, pretreatment with 10-50mug/mL STF resulted in a significant recovery. The survival rate of ECV-304 increased from 21.98% (only treated with 1mmol/L H(2)O(2)) to 64.74% (pretreated with 50microg/mL STF), which accompanied with the amounts of malondialdenhyde (MDA) decreasing from 1.6883nmol/L to 0.9628nmol/L. Furthermore, compared with control group, the 50mumol/L STF pretreatment enhanced the total antioxidant capacity (T-AOC) by 4.49 times, increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) by 85.12%, 158.94% and 94.5%,respectively, and increased the content of nitric oxide (NO) by 116.55%.Taken together, STF protect ECV-304 cells against H(2)O(2) damage by enhancing the antioxidant ability and increasing NO production.     

Susceptibility Against Grey Blight Disease-Causing Fungus Pestalotiopsis sp. in Tea (Camellia sinensis (L.) O. Kuntze) Cultivars Is Influenced by Anti-oxidative Enzymes

Reactive oxygen species (ROS) production is the first level of response by a host during stress. Even though the ROS are toxic to cell, when present in a limited amount, they act as a signalling molecule for the expression of defence-related genes and later are scavenged by either enzymatic or non-enzymatic mechanisms of the host. The different anti-oxidative enzymes like glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APO), peroxidase (POD) and polyphenol oxidase (PPO) were estimated, and their activities were compared between infected and healthy leaves of the tolerant and susceptible cultivars of tea. The infected leaves of the susceptible cultivars registered higher amount of enzyme activity when compared with the tolerant cultivars. The study reveals that the more anti-oxidative enzymes, the more susceptible the cultivar will be.     

Dose-dependent Cytotoxicity and Oxidative Stress Induced by “Naked” Fe3O4 Nanoparticles in Human Hepatocyte

The dose-dependent cytotoxicity effect on human hepatocyte(HL-7702 cells) induced by “naked” Fe3O4 nanoparticles was assessed through cell viabilities and lactate dehydrogenase(LDH) activities. Three important oxidative indexes of the cells by glutathione peroxidase(GSH-Px), superoxide dismutase(SOD) and malondialdehyde( MDA) were determined. The good correlation of the cell viabilities with their GSH-Px, SOD and MDA levels indicated that the cytotoxicity is related to activation of oxidative stress induced by Fe₃O₄ nanoparticles. The oxidative stress also leads to corresponding DNA damage in a similar dose-dependent manner, followed by the changes of cell cycle and cell apoptosis. Such work provides important experimental data for the safety evaluation of superparamagnetic Fe₃O₄ nanoparticles.