The Impact of Acute Ammonia Nitrogen Stress on the Gill Tissue Structure and Antioxidant Ability of Gills and Red and White Muscle in Juvenile Yellowfin Tuna (Thunnus albacares).

To understand the impacts of salinity stress on the antioxidation of yellowfin tuna Thunnus albacares, 72 fishes (646.52 ± 66.32 g) were randomly divided into two treatments (32‰ and 29‰) and sampled at four time points (0 h, 12 h, 24 h, and 48 h). The salinity of the control group (32‰) was based on natural filtered seawater and the salinity of the stress group (29‰) was reduced by adding tap water with 24 h aeration to the natural filtered seawater. The superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) from liver, gill, and muscle tissues were used as the antioxidant indexes in this study. The results showed that the changes of SOD and GSH-Px in the gills were first not significantly different from the control group (p > 0.05) and finally significantly higher than the control group (SOD: 50.57%, GSH-Px: 195.95%, p < 0.05). SOD activity in fish liver was not significantly changed from 0 h to 48 h (p > 0.05), and was not significantly different between the stress group and control group (p > 0.05). With the increase in stress time, GSH-Px and MDA activities in the liver of juvenile yellowfin tuna increased first (GSH-Px: 113.42%, MDA: 137.45%) and then reduced (GSH-Px: −62.37%, MDA: −16.90%) to levels similar to the control group. The SOD activity in the white and red muscle of juvenile yellowfin tuna first decreased (white muscle: −27.51%, red muscle: −15.52%) and then increased (white muscle: 7.30%, red muscle: 3.70%) to the level of the control group. The activities of GSH-Px and MDA in white and red muscle increased first (white muscle GSH-Px: 81.96%, red muscle GSH-Px: 233.08%, white muscle MDA: 26.89%, red muscle MDA: 64.68%) and then decreased (white muscle GSH-Px: −48.03%, red muscle GSH-Px: −28.94%, white muscle MDA: −15.93%, red muscle MDA: −28.67%) to the level observed in the control group. The results from the present study indicate that low salinity may lead to changes in the antioxidant function of yellowfin tuna juveniles. In contrast, yellowfin tuna juveniles have strong adaptability to the salinity of 29‰. However, excessive stress may consume the body’s reserves and reduce the body’s resistance.

The effects of acute ammonia stress on liver antioxidant, immune and metabolic responses of juvenile yellowfin tuna (Thunnus albacares)

The objective of this experiment was to study the effects of metalaxyl enantiomers on the activity of roots and antioxidative enzymes in tobacco seedlings. Water culture experiment was conducted to analyze the effects of different concentrations of metalaxyl enantiomers (30 and 10mgL-1 ) on root activity and leaf superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and malondialdehyde (MDA) content of tobacco seedlings. The results showed that metalaxyl significantly inhibited root activity and significantly improved leaf SOD, POD, and CAT activities and MDA content. A better physiological response in tobacco seedlings was observed at 30mgL-1 than at 10mgL-1 metalaxyl. The stereoselectivity for different enantiomers had no obvious effect on root activity and the leaf POD activity, but it affected significantly the SOD and CAT activities and MDA content. The SOD activity was promoted more by R-enantiomer than by S-enantiomer at 30mgL-1 metalaxyl, and the same effect was observed on CAT activity from the beginning to the end of the stress period. The MDA content under the stress by R-enantiomer was higher than that under the stress by S-enantiomer at 10mgL-1 metalaxyl.

Measurements were made on the relative water content, cell permeability, superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content in Malus micromalus seedling during dehydration in vitro in whole seedling and during dehydration in culture of different PEG 6000 concentration. The results indicated that SOD and CAT activities increased during dehydration from 0 to 3 h and decreased after dehydration for 3 h; MDA content decreased before 3 h dehydration and the MDA content and cell permeability increased significantly after 3 h in various treatments of dehydration (in vitro and in whole seedling). SOD and CAT activities in 20 days seedlings were higher than those in 10 days seedlings whereas the MDA content and cell permeability in 20 days seedlings were lower than those in 10 days seedlings. In 20 days seedlings during dehydration in vitro, SOD and CAT activities in leaves were higher than those in root and the latter was higher than those in stem. However, the MDA content and cell permeability in leaves were lower than those in root which in turn were lower than those in stem. Significant correlations and regressions exist among the changes observed in the SOD activity, CAT activity, MDA content, cell permeability and the relative water content.

海岸黑松和紫穗槐对间歇强净风和风沙流吹袭的生理响应机制

温度驯化对红耳滑龟幼龟选择体温、热耐受性和抗氧化酶活性的影响

Changes of biochemical indices in brain, liver tissue and serum in mice with Alzheimer disease after Chinese medicine treatment

AIM: To determine the effects of Cu and levamisole on concentrations of Cu and Fe in plasma and liver, and the effects of levamisole on lipid peroxidation induced by Cu intoxication in broiler chickens. METHODS: In a 2×4 factorial study, 80 one-day-old Ross PM3 broiler chicks were fed diets for 21 days containing either 8 mg/kg Cu (Low Cu) or 250 mg/kg Cu (High Cu) and were treated with 0 (L0), 4 (L4), 8 (L8) or 16 (L16) mg/kg bodyweight levamisole per day from Day 7 of the study, on three consecutive days in their drinking water. This treatment was repeated three times, at 3-day intervals. On Day 21, blood samples were collected from each bird for analysis of concentrations of Cu, Fe and malondialdehyde, and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase, catalase and glutathione peroxidase (GSH-Px). The birds were killed and liver samples collected for analysis of Cu and Fe. RESULTS: Mean concentrations of Cu and Fe in plasma, and Cu in liver, were increased overall in the High Cu groups compared with the Low Cu groups (p<0.001). Compared with the L0 treatment group on the High Cu diet, treatments L4, L8 and L16 decreased concentrations of Cu in plasma, and L8 and L16 increased concentration of Cu in liver (p<0.05). Mean activities of AST and ALT were increased in untreated birds (L0) fed the High compared with Low Cu diets (p<0.01). In birds receiving the High Cu diet, treatments L4 and L8 decreased activities of AST, and L4 and L16 decreased activity of ALT, compared with L0 (p<0.05). The High Cu diet induced an oxidative stress characterised by increased mean concentrations of malondialdehyde and decreased activities of superoxide dismutase, catalase and GSH-Px (p<0.001). Concentration of malondialdehyde, and activities of superoxide dismutase and catalase were not changed following levamisole treatment in birds on the High Cu diet, and activity of GSH-Px was decreased by the L4 and L8 treatments compared with the L0 group. CONCLUSIONS AND CLINICAL RELEVANCE: The results of the study suggest that treatment with levamisole might alleviate the harmful effects of Cu on the liver, as demonstrated by decreased activities of AST and ALT induced by a diet containing 250 mg/kg Cu.

ABSTRACTDiel rhythm in activity of antioxidant enzymes, as well as contents of glutathione and lipid peroxides, has been intensively investigated in Mammalia and Aves, however, the relevant studies about fish are few. In the present study, we examined variation in contents of cortisol, glucose and lactic acid in plasma of black sea bass Centropristis striata under natural photoperiod during a 24-h period. In addition, variation in activity of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT) and glutathione reductase (GR) as well as contents of total glutathione (T-GSH), reduced glutathione (GSH), oxidized glutathione (GSSG) and malondialdehyde (MDA) in liver and plasma of the fish were also determined. The plasma and liver samples were collected from the test fish at 3 h intervals during a 24-h cycle, with the first sampling time set at 03:00 h. No significant differences were found in glucose content and activities of GSH-PX and GR in plasma, as well as activities of SOD and GR in liver among different sampling times. In contrast, apparent variation was observed in contents of cortisol, lactic acid and MDA in plasma, activities of SOD and CAT in plasma, contents of MDA, T-GSH, GSH and GSSG in liver and activities of GSH-PX and CAT in liver between different sampling times. Moreover, contents of cortisol and MDA in plasma, SOD activity in plasma, and contents of MDA, GSH and GSSG in liver exhibited circadian rhythm, and their acrophases occurred at 06:08 h, 18:38 h, 15:09 h, 09:57 h, 23:36 h and 07:30 h, respectively. The present study indicates that some physiological parameters relating to stress response, such as cortisol and MDA contents in plasma, MDA, GSH and GSSG contents in liver and SOD activity in plasma changed at different time throughout a day in black sea bass. Therefore, caution should be taken when evaluating stress response in fish with these physiological parameters measured at different times.

In previous work, we demonstrated that some occupational workers in stressful conditions can have increases in several markers of oxidative stress when compared to other workers. We investigated two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) activities, and malondialdehyde (MDA) concentrations, according to demographics, lifestyle and occupational parameters in palliative care unit workers, and analyzed the relationship with occupational burnout. Fifty-two palliative care unit workers and 50 gender- and aged matched healthy individuals as controls were surveyed. Spectrophotometric and high-pressure liquid chromatography methods were used for biochemical determinations. No significant variation with respect to gender were detected with respect to SOD and CAT activities, MDA concentrations or occupational burnout. MDA concentrations increased with age in controls and palliative care unit workers, and we observed significant differences in MDA between controls and palliative care unit workers for all age groups. Significant variation in MDA concentrations were detected between unmarried (287.22±8.31 nmol/mg hemoglobin) and married individuals (317.18±6.24 nmol/mg hemoglobin), but not with respect to divorced individuals (288.41±5.64 nmol/mg hemoglobin). Significant differences were detected between smokers and non-smokers for SOD, CAT and MDA, but not for alcohol, coffee, tea or cola consumption. Significant differences were seen in MDA concentrations between those who frequently practice some kind of sport (280.59±7.62 nmol/mg hemoglobin) and those who never practice any kind of sport (299.12±8.09 nmol/mg hemoglobin), and between those who frequently ate fruit and greens (291.05±8.11 nmol/mg hemoglobin) and those who never eat fruit and greens (316.31±7.42 nmol/mg hemoglobin). SOD activity and MDA concentrations are higher in palliative care workers who work the evening and night shifts (p<0.01), and these workers also show significantly higher levels of stress. Our findings suggest that oxidative stress, occupational stress and occupational burnout levels are similar in men and women. Occupational stress increases oxidative stress levels probably as a response to increased generation of reactive oxygen species. Working during the evening and night shifts increases oxidative levels and burnout levels.

To study the effect of exogenous nitric oxide donor sodium nitroprusside (SNP) on antioxidant enzymes activities and lipid peroxidation of mice infected with Trichinella spiralis. BALB/c mice were infected with T. spiralis separated by the digestion method. Forty-two days post-infection, the peripheral blood and hepatic tissue from the infected or normal mice were collected. Then 4 groups were set：liver homogenate from infected mice + SNP (Group A), liver homogenate from normal mice + SNP (Group B), peripheral blood from infected mice + SNP (Group C), and peripheral blood from normal mice + SNP (Group D). The final concentrations of SNP in each group were set as 0 (blank control), 2, 5, 10 μmol/L and 30 μmol/L, respectively. After reacting with SNP at 37 ℃ for 30 min, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities, and malondialdehyde (MDA) concentration were examined and compared. The levels of SOD, CAT, GSH-Px and MDA concentration in the liver and the blood from the mice infected with T. spiralis were significantly higher than those of the normal ones (all P < 0.05). When reacted with 10 μmol/L and 30 μmol/L SNP, the SOD, GSH-Px, and CAT activities in Group A and B decreased significantly (all P < 0.05), while the liver MDA concentration reacted with 2-30 μmol/L SNP increased obviously (all P < 0.05). As reacted with 30 μmol/L SNP, the activities of blood SOD, GSH-Px, and CAT in Group C and D decreased, while the MDA concentration in blood still increased (all P < 0.01). When the SNP concentration was in the range of 2-30 μmol/L, there were a negative correlation between the SNP concentrations and SOD, GSH-Px, and CAT activities, as well as a positive correlation with the MDA concentration in the liver and blood from the mice infected with T. spiralis (all P < 0.05). T. spiralis infection could cause oxidative damage to mice, and increase SOD, GSH-Px, and CAT activities. Nitric oxide released from SNP can decrease antioxidase activities, and inhibit the antioxidant capacity of mice infected with T. spiralis.

To investigate the key role of nuclear factor E2-related factor 2 (Nrf2) in the treatment of lung injury in sepsis mice by regulating Nrf2/heme oxygenase-1 (HO-1)/high mobility group protein B1 (HMGB1) pathway. 120 male wild type (WT) and 120 Nrf2 knockout (Nrf2-KO) ICR mice were randomly divided into Sham group, H2 control group (Sham+H2 group), cecal ligation and puncture (CLP) induced sepsis model group (CLP group) and H2 intervention group (CLP+H2 group), with 30 mice in each group. The sepsis model was reproduced by CLP. The same operation was done in Sham group and Sham+H2 group except CLP. The mice in Sham+H2 group and CLP+H2 group were challenged by 2% H2 for 1 hour at 1 hour and 6 hours after operation respectively, while the mice in Sham group and CLP group only inhaled air. Twenty mice in each group were collected to observe the 7-day survival. The other mice were sacrificed at 24 hours after the reproduction of model, and the lung tissues were harvested. The activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) contents were determined by enzyme-linked immunosorbent assay (ELISA). The expressions of HO-1 and HMGB1 were determined by Western Blot, and the positive expression of HO-1 was also detected by immunofluorescence. Compared with Sham groups, the 7-day survival rates of WT and Nrf2-KO mice in CLP groups were significantly lowered [WT: 0% (0/20) vs. 100% (20/20), Nrf2-KO: 0% (0/20) vs. 100% (0/20), both P < 0.05]; the 7-day survival rates of CLP+H2 group in WT mice were significantly higher than those of CLP group [40% (8/20) vs. 0% (0/20), P < 0.05], but there was no significant difference between CLP+H2 group and CLP group in Nrf2-KO mice [0% (0/20) vs. 0% (0/200), P > 0.05]. In WT mice, compared with Sham group, the activities of SOD and CAT in lung tissue of CLP group were decreased significantly [SOD (kU/g): 131.30±28.21 vs. 251.00±22.84, CAT (kU/g): 13.43±1.52 vs. 20.76±1.63, both P < 0.01], the MDA content, the expressions of HO-1 and HMGB1 were increased significantly [MDA (μmol/g): 6.26±1.18 vs. 4.16±0.58, HO-1/β-actin: 0.160±0.045 vs. 0.023±0.005, HMGB1/β-actin: 0.656±0.055 vs. 0.005±0.001, all P < 0.05]. Compared with CLP group, the activities of SOD, CAT and HO-1 expression in lung tissue of CLP+H2 group were significantly increased [SOD (kU/g): 220.32±35.06 vs. 131.30±28.21, CAT (kU/g): 18.95±2.49 vs. 13.43±1.52, HO-1/β-actin: 0.376±0.025 vs. 0.160±0.045, all P < 0.01], while the MDA contents and HMGB1 expressions were significantly decreased [MDA (μmol/g): 4.26±0.75 vs. 6.26±1.18, HMGB1/β-actin: 0.343±0.040 vs. 0.656±0.055, both P < 0.05]. In Nrf2-KO mice, compared with Sham group, the activity of CAT in CLP group was significantly lowered (kU/g: 12.28±1.49 vs. 19.11±1.53, P < 0.01), MDA contents and the expressions of HO-1 and HMGB1 were significantly increased [MDA (μmol/g): 6.85±0.54 vs. 4.59±0.50, HO-1/β-actin: 0.063±0.005 vs. 0.021±0.003, HMGB1/β-actin: 0.713±0.035 vs. 0.005±0.001, all P < 0.01], while there was no significant difference in SOD activity (kU/g: 114.19±9.94 vs. 135.75±28.10, P > 0.05). There was no significant difference in above parameters between CLP+H2 group and CLP group. H2 inhibits lung injury in septic mice through Nrf2/HO-1/HMGB1 pathway. Nrf2 plays a major role in the treatment of septic lung injury by H2.

Two varieties of muskmelon were cultivated in hydroponics culture using the following [Ca] in nutrient solution under hypoxia with 4mmol·L Ca (hypoxia), hypoxia with 10mmol·L Ca (hypoxia+Ca), hypoxia with 0mmol·L Ca (hypoxia-Ca), and normal dissolved oxygen with 4mmol·L Ca was the control. Leaf samples were collected at 0, 2, 4, 6 and 8d from all treatments for fresh weight, reactive oxygen species (ROS) and nitrogen metabolism analyses. The results showed that compared to control treatment, the fresh weights of both varieties were decreased and activities of antioxidant enzymes, productive rate of ROS, contents of MDA and NH4-N, NO3-N were increased under hypoxia. Calcium application treatment alleviated the harmful effects of hypoxia to seedlings, as manifested by the higher levels of fresh weights, activities of antioxidant enzyme, contents of NH4-N, NO3-N under hypoxia, while the ROS productive rate and MDA content were lower. The calcium-deficient treatment aggravated the harmful effects of hypoxia, which were reversed by calcium application. The different levels of response by the two varieties show differences in tolerance to hypoxia. INTRODUCTION Hypoxia in the root-zone is thought to be a major determinant in the adverse effects of nutrient solution culture (Gao et al., 2004b). Oxygen deficiency might first be sensed by the mitochondrial electron transport chain, caused by NADP(H) oxidative blockage and the reduced adenylate energy charge of the cell (Subbaiah and Sachs, 2003). As a second messenger, [Ca] in cytoplasm rapidly increases under external stimuli, which is involved in perception and regulation of response of plants to environmental stress (Pandey et al., 2000). There is ample evidence for the role of Ca in plant growth and development, maintenance and modulation of various cell functions under environmental stress, such as cold (Gao et al., 2004a), drought (Sulochana et al., 2002), anoxia (Wang et al., 2002). Subbaiah et al (2003) demonstrated that Ca is a transducer of low O2 signal, but a detailed mechanism of events and the relationship that exists between exogenous application Ca and plant growth, reactive oxygen species (ROS) and nitrogen metabolism under hypoxia are not clear. In the present study, muskmelon seedlings were used to examine the effects of exogenous application Ca and exclusion Ca in nutrient solution under hypoxia on growth, ROS and nitrogen metabolism and to elucidate the relationship between Ca enhancement of hypoxia tolerance and metabolism of ROS and nitrogen metabolism. MATERIALS AND METHODS Two varieties of muskmelon (Cucumis melo L. var. raticulalus Naud) ‘Xiyu No.1’ and ‘Dongfangxingguang’ were cultivated in autumn in 2003. At the 3 true-leaf stage, seedlings were removed from the nutrient cubes, the roots were rinsed with distilled water, and uniform seedlings were divided into four groups then transferred into Hoagland nutrient solution (pH 6.3±0.1, EC 2.0~2.2) in plastic containers (65L). After 2d culture, the first set of seedlings was transferred into normal Hoagland nutrient solution (4 mmol L Ca) and exposed to normal dissolved oxygen (DO) by using vigorous aeration (30min/h) Proc. IC on Greensys Eds.: G. van Straten et al. Acta Hort. 691, ISHS 2005 322 to keep DO at 8±0.2mg L (Control). The second set of seedlings were cultured in normal Hoagland nutrient solution containing 4mmol L Ca but exposed to reduced levels of dissolved oxygen (hypoxia). The O2 was balanced with N2 by using a DO analyzer (Quantum-25, Quantum Analytical Instruments Inc, American) to keep DO at 2±0.2mg L. The third and fourth groups of seedlings were cultured in DO 2±0.2mg L with exogenous application of Ca 10mmol LCa (Hypoxia+Ca) and without Ca (Hypoxia-Ca) in nutrient solution respectively. Superoxide dismutase (SOD) activity was determined by assaying its ability to inhibit the photochemical reduction of nitroblue tetrazolium (NBT). One unit of SOD activity was defined as the amount of the enzyme to bring about 50% inhibition of the photochemical reduction of NBT (Giannopolitis and Ries 1977). Peroxidase enzyme (POD) activity was measured by measuring the increase in absorbance at 470nm as Guaiacol was oxidized according to the method of Kwak (1996). Catalase (CAT) activity was determined according to the method of Dhindsa (1981) by measuring the decrease in absorbance at 240nm for 1min following the decomposition of H2O2. One unit of CAT activity was defined as decrease of 0.1A value for required enzyme quantity. Hydrogen peroxide (H2O2) content determination was performed by monitoring the increase in absorbance at 550nm according to the method of Matsumura (2002). Superoxide radical ion (O2) productive rate was determined according to the method of Wang (1990) and sodium nitrite was used as standard. Malondialdehyde (MDA) content was determined by reaction of trichloroacetic acid (TCA) and thiobarbituric acid (TBA) according to the method of the method of Dhindsa (1981). Nitrate-nitrogen (NO3-N) and ammonium-nitrogen (NH4-N) content was determined according to the method of Gao (2004a), potassium nitrate and leucine was used as the standards respectively. Statistical analysis of the data was performed by Excel statistical software. Duncan Multiple Range Test (SAS) was used for mean separation. RESULTS Effect of Ca on Fresh Weight of Muskmelon Seedlings under Hypoxia Table1 indicates that after 8d of culture under hypoxia conditions, the fresh weights of seedlings in hypoxia+Ca, hypoxia alone and hypoxia-Ca decreased compared with those of the control treatment. The decrease in fresh weight under hypoxia-Ca was greater than that of hypoxia alone, and under hypoxia+Ca was the least. The fresh weight of ‘Dongfangxingguang’ was higher than that of ‘Xiyu No.1’ seedlings under all treatments. Effect of Ca on the Activity of Antioxidant Enzymes under Hypoxia SOD activity in ‘Xiyu No.1’ and ‘Dongfangxingguang’ seedlings under hypoxia alone and hypoxia+Ca increased significantly, reaching a peak 2d after hypoxia treatment, however, the SOD activity of hypoxia+Ca treatment was higher than those of hypoxia alone (Fig.1). SOD activity with hypoxia-Ca treatment increased slightly but was significantly lower than that control during the hypoxia at 6-8d. SOD activity of hypoxia-Ca and control treatments was lower than those of hypoxia alone and hypoxia+Ca treatment. POD activity of seedlings of both varieties with hypoxia+Ca treatment increased significantly compared to the other three treatments, peaking at 6d of hypoxia treatment (Fig. 1). POD activity of hypoxia alone and hypoxia-Ca treatments increased initially then decreased, but they were both higher than that of the control at peak activity. Similar to SOD and POD activities, CAT activity of both varieties with hypoxia+Ca, hypoxia alone and hypoxia-Ca treatments increased, peaking at 4d after hypoxia treatment (Fig.1). CAT activity with hypoxia+Ca treatment was higher than that of hypoxia alone. In ‘Xiyu No.1’ seedlings, the Ca deficient treatment (hypoxia-Ca) was not different from the control. Generally, antioxidant enzyme activity was consistently higher for ‘Dongfangxingguang’ than for ‘Xiyu No.1’ seedlings for any one treatment and time of determination.

海滨滨麦叶片和根对不同厚度沙埋生理响应差异分析

Lipid Peroxidation and Antioxidative Enzymes of Two Turfgrass Species Under Salinity Stress