Transcript Levels Of Superoxide Dismutase Research Articles

Protective effect of quercetin on carp cardiac damage caused by difenoconazole via alleviating oxidative damage, inflammatory responses, and apoptosis

Pollution of aquatic environment by difenoconazole (DFZ) significantly affects survival and safety of freshwater aquaculture. Due to its anti-inflammatory and antioxidant properties, plant-derived quercetin (QUE) is often used as a dietary supplement. The main purpose of this study was to explore the protective effect of QUE on heart damage caused by exposure to pesticide DFZ and the potential mechanisms of these effects. This study found that QUE could effectively reduce the myocardial enzyme spectrum index of carp after exposure to DFZ, increase the levels of total antioxidant capacity (T-AOC), glutathione (GSH), and catalase (CAT), inhibit the content of malondialdehyde (MDA), and increase the transcription levels of superoxide dismutase (sod), glutathione peroxidase (gsh-px), and cat. By reducing the expression of keap1, QUE increased the transcription levels of nrf2 and nqo-1, reduced the production of reactive oxygen species (ROS) in the heart after exposure to DFZ, and restored the redox homeostasis of the heart. QUE upregulated the expression of anti-inflammatory cytokines il-10 and tgf-β1 levels, downregulated the transcription levels of pro-inflammatory factor inos, il-1β, il-6 and tnf-α, and alleviated the in vivo redox imbalance caused by exposure to DFZ, leading to myocardial interstitial inflammatory cell infiltration. The results showed that QUE inhibited the apoptosis after exposure to DFZ by affecting the expression of apoptotic factors in the mitochondrial apoptotic pathway. In summary, QUE can effectively decrease myocardial injury caused by exposure to DFZ in aquatic environment.

Assessment of salt and drought stress on the biochemical and molecular functioning of onion cultivars.

Salt and drought stress are the main environmental constraints that limit onion growth and productivity. Türkiye is the fifth largest onion producer, whereas the stress conditions are increasing in the region, resulting in poor crop growth. A current study was conducted under greenhouse conditions according to a completely randomized design with factorial arrangements to evaluate the performance of onion cultivars. Plants were subjected to salt stress with an application of 750 mM NaCl and drought stress was applied by depriving plants of irrigation water for 20 days to measure biochemical and transcript changes. The antioxidant activities of the cultivars were quantified by using four different methods, i.e., 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays, cupric reducing antioxidant capacity, 2,2-Diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power (FRAP). The damage to pigments, phenolic, osmolytes, and hydrogen peroxide (H2O2) accumulation was also evaluated. Results revealed that the cultivars "Elit and Hazar" had higher H2O2, maximum damage to pigments, and least accumulation of phenolics and osmolytes under both stress conditions. The cultivar "Şampiyon" performance was better under salt stress but exhibited a poor antioxidant defensive mechanism under drought stress conditions. The remaining cultivars suggested a resilient nature with a higher accumulation of osmolytes, antioxidants and phenolics. The change in transcript levels further strengthened the response of resilient cultivars; for instance, they showed higher transcript levels of superoxide dismutase, ascorbate oxidase and transcription factors (WRKY70, NAC29). It helped alleviate the oxidative stress in tolerant cultivars and maintained the physio-biochemical functioning of the cultivars.. The results of the current study will fill the gap of missing literature in onion at biochemical and molecular levels. Additionally, resilient cultivars can effectively cope with abiotic stresses to ensure future food security.

Exogenous uniconazole enhances tolerance to chilling stress in mung beans (Vigna radiata L.) through cross talk among photosynthesis, antioxidant system, sucrose metabolism, and hormones

To monitor the role of exogenous uniconazole in mitigating chilling stress, this study investigated the effect of foliar spraying of 50 mg L−1 uniconazole on the chilling (15 °C) tolerance of mung beans at the flowering stage. The results showed that uniconazole significantly enhanced the reactive oxygen species (ROS) scavenging ability of mung beans by increasing the superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) activities, the contents of ascorbic acid (AsA) and glutathione (GSH), and the transcription levels of SOD and POD under chilling stress. The uniconazole applications also drastically increased the net photosynthetic rate (Pn), maximum net photosynthetic rate (Pnmax), maximum quantum yield of PSII (Fv/Fm), and the expression levels of the corresponding photosynthetic genes PsbO, PsbP, PsbQ, PsbY, and Psb28. This, in turn, resulted in a higher sucrose content. Meanwhile, uniconazole increased the indole-3-acetic acid (IAA) content but reduced the gibberellin A3 (GA3) content under chilling stress. During the recovery period, the photosynthetic parameters and ROS of plants receiving uniconazole recovered faster, and the antioxidant activity and non-antioxidant contents were higher than in chilling-treated plants. Additionally, chilling stress markedly reduced the pod number per plant, grain number per plant, and 100-seed weight, whereas uniconazole significantly increased the grain weight per plant by 53.47% compared to the chilling treatment. These results strongly suggest that uniconazole can effectively protect mung beans from chilling stress damage by protecting the photosynthetic machinery and enhancing the antioxidant capacity to quench excessive ROS caused by chilling stress. These effects are closely relevant to chilling tolerance enhancement and yield improvement in mung beans.

Mortality, Enzymatic Antioxidant Activity and Gene Expression of Cabbage Aphid (Brevicoryne brassicae L.) in Response to Trichoderma longibrachiatum T6.

Aphids are one of the most common insect pests in greenhouse and field crops worldwide, causing significant crop yields and economic losses. The objective of this study was to determine the mortality, enzymatic antioxidant activity and gene expression of cabbage aphids (Brevicoryne brassicae L.) in response to Trichoderma longibrachiatum T6 (T6) at different time points from Day 1 to 7 after inoculation. Our results showed that the highest mortality of B. brassicae was observed on Day 7 at a concentration of 1 × 108 spores ml−1 (73.31%) after inoculation with T6 compared with the control on Day 7 (11.51%). The activities of the enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX) and glutathione S-transferase (GST) were increased by 52.98%, 44.77%, 48.26%, 49.39%, 45.13% and 39.67%, respectively on Day 3 after inoculation with T6 compared to the control. Howerver increased days post treatment (dpt) decreased the activities of SOD, POD, CAT, APX, GPX and GST enzymes by 20.79%, 21.05%, 13.75%, 20.45%, 25.38%, and 19.76% repectively on Day 7 compared to control. The transcript levels of SOD, POD, CAT, GPX, and GST genes were increased by 10.87, 9.87, 12.77, 6.22 and 4.07 respectively at Day 3 after inoculation with T6 in comparison to the control. However, the SOD, POD, CAT, GPX, and GST transcription levels decreased by 0.43, 0.44, 0.35, 0.52 and 0.47 respectively, compared to control at Day 7. Our results suggest that the T6 strain has a potential effect on the antioxidant activity and mortality of B. brassicae and therefore could be used as a natural biocontrol agent against B. brassicae in the future.

MoS2 nanoparticles induce behavioral alteration and oxidative stress mediated cellular toxicity in the social insect Oecophylla smaragdina (Asian weaver ant)

The study evaluates molybdenum disulfide (MoS2) nanoparticles (NPs) induced oxidative stress during cellular toxicity in an invertebrate in vivo system, the weaver ant. The lethal concentration was checked and LC50 was obtained as 50 µg/mL. Feeding assay and the photoluminescence activity confirmed the ingestion of MoS2 NPs by the organism. Behavioral assays showed altered grooming behavior in the MoS2 NP fed ants. A drastic decrease in the hemocyte count in the MoS2 NP fed ants revealed the anti-proliferative role of MoS2. This was further confirmed by 5-bromo-2′-deoxyuridine (BrdU) labeling assay. MoS2 NPs induced apoptotic activity was also observed in the hemocytes by acridine orange/ethidium bromide (AO/EB) staining. The level of oxidative stress during cellular toxicity was observed. An increased reactive oxygen species (ROS) level was observed in the MoS2 NP fed ants when compared to the control group. The increased activity of superoxide dismutase (SOD) and the lipid peroxidation (LPO) product were observed. While, the activities of catalase (CAT) and glutathione-s-transferase (GST) and the glutathione content (GSH) were decreased by MoS2 NPs. The transcript levels of SODs, CAT and GST were up regulated in the treated group. Our results suggest that MoS2 NPs induced oxidative stress mediates the cellular toxicity in the foragers of the weaver ant.

Physiological, transcriptional, and metabolic alterations in spaceflight-subjected Senna obtusifolia

Senna obtusifolia is a widely used medicinal herb in Asian countries. To select elite cultivars, S. obtusifolia seeds were carried by “ShenZhou Ⅷ” recoverable satellite to space. Three spaceflight-subjected lines (SP-lines), namely QC10, QC29, QC46, and their ground control line (GC-line) were cultivated on the ground. Previous studies demonstrated that biological traits and secondary metabolites are different between SP-lines and GC-line. Here, we combined physiological, transcriptional, and metabolic studies to compare the differences between SP-lines and GC-line. The results showed that activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and monodehydroascorbate reductase (MDHAR) were dramatically increased in SP-lines as compared to that of GC-line. Transcript levels of SOD, POD, CAT, APX, and MDHAR were significantly up-regulated in SP-lines. Malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents decreased in SP-lines. Seed yields of QC29 and QC46 were considerably higher than that of GC-line. Besides, QC29 had significantly higher aurantio-obtusin content. Pearson correlation coefficient analysis revealed positive relationships between POD and aurantio-obtusin, as well as APX and aurantio-obtusin. In conclusion, SP-lines have higher antioxidant gene expression level and antioxidant enzyme activity as compared to that of GC-line. With higher seed yield and aurantio-obtusin content, QC29 can be used to breed elite S. obtusifolia cultivars. This study provides a new insight in SP-lines and paves the way to breed elite S. obtusifolia cultivars in the future.

Comparative orchestrating response of four oilseed rape (Brassica napus) cultivars against the selenium stress as revealed by physio-chemical, ultrastructural and molecular profiling

Selenium (Se) is an essential micro-element for human and animals. In higher plants, Se essentiality or phyto-toxicity is less explored. Therefore, we aimed to examine the effects of Se (0, 25, 50, and 100 µM) as sodium selenite on the physio-chemical, cell ultra-structural and genomic alterations in hydroponically grown seedlings of four cultivars of B. napus (cvs. Zheda 619, Zheda 622, ZS 758, and ZY 50). Results showed that excessive (100 µM) Se (IV) exhibited significant reduction in plant growth parameters, declined pigment contents, lower water-soluble protein levels, and overproduction of H2O2 and MDA contents. A significant increase in antioxidant enzyme activities and transcript levels of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR), except catalase (CAT) were noticed in the leaves and roots. Non-enzymatic antioxidants including glutathione (GSH) and oxidized glutathione (GSSG), except GSSG in roots were enhanced under higher Se (IV) levels. Transmission electron microscopy analysis revealed the ultrastructural damages in leaf mesophyll and root tip cells induced by excessive Se (IV). Less-significant phytotoxic effects were observed in above-mentioned parameters at 50 µM Se (IV). Overall, Se (IV) supplementation at 25 µM displayed marginal beneficial effect by enhancing plant growth, pigment contents, protein levels and restrict H2O2 and MDA overproduction. A marginal increase/decrease in ROS-detoxifying enzymes (except CAT activity) and elevated GSH and GSSG levels were noticed. The accumulation of Se (IV) was much higher in roots as compared to leaves. This accumulation was maximum in Zheda 622 and minimum in ZS 758, followed by Zheda 619 and ZY 50. Overall findings showed that Zheda 622 was the most sensitive and ZS 758 as most tolerant to Se (IV) phyto-toxicity. In addition, Se (IV) was found beneficial until 25 µM Se (IV) but phytotoxic at higher Se levels especially at 100 µM Se (IV).

The morphological changes and molecular biomarker responses in the liver of fluoride-exposed Bufo gargarizans larvae

The goal of the current study was to evaluate the negative influences of fluoride on liver of Bufo gargarizans larvae. B. gargarizans larvae were treated with 42.4mgF-/L for 0, 24, 48 and 72h at Gosner stage 37. The morphological changes and responses of molecular biomarkers involved in lipid metabolism, oxidative stress and apoptosis were examined in liver. Disappearance of cell boundaries, degeneration of hepatic parenchyma cells and significant increase in the number of melanomacrophage centres and the quantity of lipid droplets were found in the liver treated with 42.4mgF-/L for 72h. In addition, in the relative expression of acetyl CoA carboxylase 1 (ACC-1), fatty acid elongase 1 (FAE-1), sterol carrier protein 2 (SCP-2), and carnitine palmitoyltransferase-1 (CPT-1), decrease was observed after 24, 48 and 72h of 42.4mgF-/L exposure. Furthermore, the transcript levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were downregulated in tadpoles exposed for 24, 48 and 72h to 42.4mgF-/L, while the transcript level of heat shock protein 90 (HSP90) was upregulated at 42.4mgF-/L for 72h. Also, mRNA expression of Bcl-2-associated transcription factor 1(BCLAF1) and thyroid hormone receptors (TRα and TRβ) was significantly upregulated in tadpoles treated with 42.4mgF-/L for 72h. Therefore, our results suggested that the liver injury induced by fluoride might result from disruption of lipid metabolism, oxidative damage and apoptosis.

Exogenous Melatonin Suppresses Dark-Induced Leaf Senescence by Activating the Superoxide Dismutase-Catalase Antioxidant Pathway and Down-Regulating Chlorophyll Degradation in Excised Leaves of Perennial Ryegrass (Lolium perenne L.).

Leaf senescence is a typical symptom in plants exposed to dark and may be regulated by plant growth regulators. The objective of this study was to determine whether exogenous application of melatonin (N-acetyl-5-methoxytryptamine) suppresses dark-induced leaf senescence and the effects of melatonin on reactive oxygen species (ROS) scavenging system and chlorophyll degradation pathway in perennial grass species. Mature perennial ryegrass (Lolium perenne L. cv. ‘Pinnacle’) leaves were excised and incubated in 3 mM 2-(N-morpholino) ethanesulfonic buffer (pH 5.8) supplemented with melatonin or water (control) and exposed to dark treatment for 8 days. Leaves treated with melatonin maintained significantly higher endogenous melatonin level, chlorophyll content, photochemical efficiency, and cell membrane stability expressed by lower electrolyte leakage and malondialdehyde (MDA) content compared to the control. Exogenous melatonin treatment also reduced the transcript level of chlorophyll degradation-associated genes and senescence marker genes (LpSAG12.1, Lph36, and Lpl69) during the dark treatment. The endogenous O2- production rate and H2O2 content were significantly lower in these excised leaves treated with melatonin compared to the water control. Exogenous melatonin treatment caused increases in enzymatic activity and transcript levels of superoxide dismutase and catalase but had no significant effects on ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase. The content of non-enzymatic antioxidants, such as ascorbate and dehydroascorbate, were decreased by melatonin treatment, while the content of glutathione and oxidized glutathione was not affected by melatonin. These results suggest that the suppression of dark-induced leaf senescence by exogenous melatonin may be associated with its roles in regulating ROS scavenging through activating the superoxide dismutase-catalase enzymatic antioxidant pathway and down-regulating chlorophyll degradation in perennial ryegrass.

Growth inhibition and altered gene transcript levels in earthworms (Eisenia fetida) exposed to 2,2',4,4'-tetrabromodiphenyl ether.

The toxic effects of the ubiquitous pollutant 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on the earthworm Eisenia fetida were assessed by determining growth-inhibition and gene transcript levels of superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST), and transcriptional changes of the stress-response gene (heat-shock protein 70 [Hsp70]). Somatic growth and growth-inhibition rates in all BDE-47-treated groups were significantly different from those of the controls. The SOD gene transcripts were upregulated at all exposure doses and reached the maximum at the concentration of 400 mg/kg dry weight (dw) (3.84-fold, P < 0.01), which protected earthworms from oxidative stresses. However, downregulation of CAT and Hsp70 was present in all exposure doses and reached to the minimum at concentrations of 400 mg/kg dw (0.07-fold, P < 0.01 and 0.06-fold, P < 0.01, respectively). Upregulation of GST gene transcript level presented significant changes at concentrations of 10 (2.69-fold, P < 0.05) and 100 mg/kg dw (2.55-fold, P < 0.05). SOD maintained a dynamic balance to upregulate SOD expression to eliminate superoxide radicals in all dosage treatments, but downregulation of CAT decreased the ability to eliminate hydrogen peroxide. These changes could result in biochemical and physiological disturbances in earthworms.

Intra-specific variations in expression of stress-related genes in beech progenies are stronger than drought-induced responses

Rapidly decreasing water availability as a consequence of climate change is likely to endanger the range of long-lived tree species. A pressing question is, therefore, whether adaptation to drought exists in important temperate tree species like European beech (Fagus sylvatica L.), a wide-spread, dominant forest tree in Central Europe. Here, five beech stands were selected along a precipitation gradient from moist to dry conditions. Neutral genetic markers revealed strong variation within and little differentiation between the populations. Natural regeneration from these stands was transferred to a common garden and used to investigate the expression of genes for abscisic acid (ABA)-related drought signaling [9-cis-epoxy-dioxygenase (NCED), protein phosphatase 2C (PP2C), early responsive to dehydration (ERD)] and stress protection [ascorbate peroxidase (APX), superoxide dismutase (SOD), aldehyde dehydrogenase (ALDH), glutamine amidotransferase (GAT)] that are involved in drought acclimation. We hypothesized that progenies from dry sites exhibit constitutively higher expression levels of ABA- and stress-related genes and are less drought responsive than progenies from moist sites. Transcript levels and stress responses (leaf area loss, membrane integrity) of well-irrigated and drought-stressed plants were measured during the early, mid- and late growing season. Principal component (PC) analysis ordered the beech progenies according to the mean annual precipitation at tree origin by the transcript levels of SOD, ALDH, GAT and ERD as major loadings along PC1. PC2 separated moist and drought treatments with PP2C levels as important loading. These results suggest that phosphatase-mediated signaling is flexibly acclimated to the current requirements, whereas stress compensatory measures exhibited genotypic variation, apparently underlying climate selection. In contrast to expectation, the drought responses were less pronounced than the progeny-related differences and the transcript levels were constitutively lower in beeches from dry than from moist sites. These results imply that beeches from dry origins may have evolved mechanisms to avoid oxidative stress.

3 OXIDATIVE STRESS INDUCED CHANGES IN EPIGENETIC MODIFYING GENE mRNA IN PRE-IMPLANTATION IN VITRO BOVINE EMBRYOS

In vitro embryo culture systems introduce a myriad of environmental changes to embryos when compared with in vivo development. Accordingly, in vitro culture has been associated with decreased embryo development rates and alterations to the fetal epigenome. We hypothesized that an interaction exists between oxidative stress and the expression of key epigenetic modifying enzymes. To test this hypothesis, we used quantitative PCR to measure transcript levels of several genes known to be associated with oxidative stress and epigenetic modifications during bovine in vitro pre-implantation development. Epigenetic modifiers examined included histone deacetylases (SIRT1, SIRT6), whose actions result in gene repression; a histone demethylase (JMJD1A) associated with gene activation; and DNA hydroxylases (TET1-3), which have been associated with conversion of 5-methylcytosine to 5-hydroxy-methylcytosine. Bovine ova were matured, fertilized, and cultured in vitro according to standard laboratory procedures. At 18 h post-fertilization, cumulus cells were removed and presumptive zygotes were cultured in 5% CO2 and air (high O2), or 5% CO2, 5% O2 and 90% N (low O2). Groups of 16-cell- (n = 20) and blastocyst- (n = 15) stage embryos were collected, RNA was extracted using an RNeasy Mini Kit, and cDNA was generated using qScript reagents. Quantitative PCR was performed using Perfecta SYBR to determine transcript levels of superoxide dismutase 2, mitochondrial (SOD2), lactate dehydrogenase A (LDHA), hypoxia-inducible factor 1 alpha (HIF1A), hypoxia-inducible factor 2 alpha (HIF2A), histone deacetylase 1 (HDAC1), jumonji domain containing 1A (JMJD1A), sirtuin 1 (SIRT1), sirtuin 6 (SIRT6), tet oncogene 1 (TET1), tet oncogene 2 (TET2), and tet oncogene 3 (TET3) in 3 replicates (each measured in triplicate). Data were analyzed using the comparative Ct method normalized to the geometric mean of 2 endogenous control genes [glyceraldehyde-3-phosphate dehydrogenase (GAPDH), succinate dehydrogenase (SDHA)]. Statistical analyses were performed using a paired t-test comparing the relative expression of each gene in high O2 with low O2 within each individual embryo stage. Blastocyst development rates were 35% (n = 710 oocytes) for low O2 and 19% for high O2 (n = 1221 oocytes; P &lt; 0.001). The HIF2A transcript levels were elevated at the 16-cell stage in high-O2 embryos (4.26 ± 0.55 v. 1.22 ± 0.22; P &lt; 0.01), but were not different at the blastocyst stage. Elevated HIF2A was likely in response to oxidative stress and was associated with elevated levels of JMJD1A (1.73 ± 0.18 v. 1.15 ± 0.19), SIRT1 (1.68 ± 0.20 v. 1.09 ± 0.16), SIRT6 (2.30 ± 0.34 v. 1.07 ± 0.13), and TET2 (3.44 ± 0.89 v. 1.23 ± 0.19; P &lt; 0.05) in high-O2 16-cell embryos. The JMJD1A (1.31 ± 0.17 v. 1.05 ± 0.10), SIRT1 (1.45 ± 0.24 v. 1.05 ± 0.11), and TET1 (1.45 ± 0.19 v. 1.02 ± 0.07) transcripts were also elevated in high-O2 blastocysts, whereas TET3 transcript levels were lower (0.69 ± 0.12) than in low O2 (1.07 ± 0.14; P &lt; 0.05). Genes associated with epigenome modification and with oxidative stress were altered in response to the high oxygen tension. The lower blastocyst rate observed in the high-O2 group may be due to the damaging effects of oxidative stress and this stress alters transcript levels associated with the epigenome. These data suggest that embryos surviving oxidative stress may exhibit epigenetic changes that could influence subsequent development.

Early defense responses in the freshwater bivalve Corbicula fluminea exposed to copper and cadmium: Transcriptional and histochemical studies

The aim of the present study was to measure the early effects of copper (10 and 50 μg L(-1)), cadmium (2, 10, and 50 μg L(-1)) and mixtures of these metals in the freshwater bivalve Corbicula fluminea exposed for 12 h in laboratory. Transcription levels of superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx), pi-class glutathione S-transferase (pi-GST), metallothionein (MT) in digestive gland and gills, and response of lysosomal system and neutral lipids in digestive gland were determined after the exposure period. Results showed that lysosomal system, neutral lipids content, and mRNA levels were modified, suggesting their early response against oxidative stress and their important role in cell integrity. The integrated biomarker response was calculated and showed that the effects of the combinations of Cu and Cd on the biomarker responses are additive. MT and pi-GST mRNA expression correspond to the largest ranges of response. As efficient biomarkers should have an early warning capacity, SOD, CAT, Se-GPx, pi-GST, MT transcripts levels, lysosomal system, and neutral lipids could be used as biomarkers of metal contamination in the aquatic environment.

Myocardial oxidative stress following sub-chronic and chronic oral cadmium exposure in rats

We investigated the effect of oral cadmium intoxication on the antioxidant/prooxidant status in serum and heart. Wistar rats, separated into four groups, that received: (1) tap water for 60 days (control); (2), (3) and (4) Cd 2+ (15 ppm)-containing water, during 15, 30 and 60 days, respectively. Lipoperoxidation increased in serum and heart of group 4. Circulating paraoxonase-1 activity was higher in groups 2 and 3. Protein carbonyl-groups increased while total and reduced glutathione levels decreased in the heart after 15 days of cadmium intoxication. Cardiac catalase activity was higher in groups 3 and 4 but glutathione peroxidase activity diminished in the heart of all poisoned groups. Superoxide dismutase transcript levels as well as Nrf2 expression also increased in the heart of groups 2 and 3, while gp91phox and p47phox mRNA levels rose only in group 3. We suggest cadmium intoxication modifies antioxidant/prooxidant ratio in serum and heart in a time-of-exposure-dependent way.

Oxidative stress is transient and tissue specific during cold acclimation of threespine stickleback

Linkages between cold acclimation and oxidative stress in fishes are unclear and contradictory results have been published. We sought to determine whether oxidative stress occurs during cold acclimation of threespine stickleback (Gasterosteus aculeatus), and, if so, when it occurs and whether it varies among tissues. Fish were warm (20°C) or cold (8°C) acclimated for 9 weeks, and harvested during acclimation. Oxidative stress was assessed in oxidative and glycolytic muscles and liver by measuring levels of protein carbonyls and glutathione, and the activity and transcript levels of superoxide dismutase (SOD). Protein carbonyl levels increased in liver after 1 week at 8°C and then decreased after week 4, and remained unchanged in glycolytic and oxidative muscle. Glutathione levels increased in liver on day 3 of cold acclimation and may minimize oxidative stress later during acclimation. When measured at a common temperature, the activity of SOD increased in oxidative and glycolytic muscles on day 2 of cold acclimation, and on day 3 in liver, and remained elevated in all tissues compared with warm-acclimated animals. When measured at the acclimation temperature, the activity of SOD was significantly higher only at week 9 in oxidative muscle of cold-acclimated stickleback compared with warm-acclimated fish, and remained constant in glycolytic muscle and liver. Increased SOD activity in oxidative muscle may be required to prevent oxidative stress brought about by increased mitochondrial density. In both muscle and liver, SOD activity increased independently of an increase in transcript level, suggesting post-translational modifications regulate SOD activity.

Expression of hepatic antioxidant genes in l-thyroxine-induced hyperthyroid rats: Regulation by vitamin E and curcumin

Earlier we have demonstrated that oral supplementation of vitamin E and curcumin alleviates hyperthyroidism-induced oxidative stress and distorted histoarchitecture in rat liver [5]. To delineate the underlying mechanism of protection, the present study was undertaken to investigate the regulatory role of vitamin E and curcumin on antioxidant gene (AOG) expression in hyperthyroid rat liver. Adult male rats were rendered hyperthyroid by administration of 0.0012% l-thyroxine in their drinking water, while vitamin E (200 mg/kg body weight) and curcumin (30 mg/kg body weight) were supplemented orally for 30 days. l-Thyroxine-induced hyperthyroidism decreased the transcript levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx1) and glutathione reductase (GR) in liver. Alleviated message levels of SOD and CAT were noticed following simultaneous administration of curcumin and vitamin E to hyperthyroid rats. Moreover vitamin E or curcumin treatment ameliorated GPx1 and GR mRNA levels. Translated products of AOGs showed differential expression in the liver of hyperthyroid rats, where Cu/Zn SOD (SOD1), CAT and GR were decreased in contrast to Mn SOD (SOD2) and GPx1. Vitamin E administration was able to alleviate SOD1, CAT and GR translated products while only CAT protein was restored to normal level by curcumin. Co-administration of both antioxidants normalized GPx1 protein expression. Interestingly decreased activities of cytosolic CAT and GPx1 were alleviated following vitamin E and curcumin administration. Increased mitochondrial SOD1 and decreased GR activities were also normalized by antioxidant treatment. Above findings suggest that administration of vitamin E and curcumin may alleviate the hepatic AOG expression in hyperthyroid rats.

Changes in H2O2 content and antioxidant enzyme gene expression during the somatic embryogenesis of Larix leptolepis

Hydrogen peroxide (H2O2) content and transcript levels of genes encoding superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) antioxidant enzymes were investigated during different stages of somatic embryogenesis in Larix leptolepis. H2O2 content was lowest on day 0 when embryogenic callus was incubated on Murashige and Skoog (MS) medium supplemented with polyethylene glycol (PEG). This content began to increase when callus was transferred to the same medium but containing abscisic acid (ABA), and reached a peak at day 3 following incubation. The level of H2O2 dropped from day 7 to day 10, peaked at day 21, then dropped again at day 24 and day 35, but increased when somatic embryos reached maturity at day 45. Transcript levels of SOD, CAT, and APX were lowest when somatic embryos were cultured on callus induction medium without ABA. When calli were transferred onto somatic embryo maturation medium, expression patterns of SOD, CAT, and APX varied, and transcript levels at all stages were higher than those at d 0. SOD expression was highest at day 3. Whereas, CAT expression levels were low during early stages of somatic embryogenesis, but increased at day 21, declined at days 24 and 35, and then began to increase again at day 45. APX gene expression patterns were highest at days 3, 21, and 45. These results suggested that ABA was essential for promoting somatic embryogenesis of L. leptolepis. Moreover, ABA induced production of H2O2 and other active oxygen species (AOS), and mediated CAT, SOD, and APX gene expression in somatic embryogenesis of L. leptolepis.

Zebrafish (Danio rerio) as a model for investigating the safety of GM feed ingredients (soya and maize); performance, stress response and uptake of dietary DNA sequences

A 20-d zebrafish (Danio rerio) feeding trial, in which a near doubling of fish weight was achieved, was conducted with GM feed ingredients to evaluate feed intake, growth, stress response and uptake of dietary DNA. A partial aim of the study was to assess zebrafish as a model organism in GM safety assessments. Roundup Ready soya (RRS), YieldGard Bt maize (MON810) and their non-modified, maternal, near-isogenic lines were used in a 2 x 2 factorial design. Soya variety and maize variety were the main factors, both with two levels; non-GM and GM. Compared with fish fed non-GM maize, those fed GM maize exhibited significantly better growth, had lower mRNA transcription levels of superoxide dismutase (SOD)-1 and a tendency (non-significant) towards lower transcription of heat shock protein 70 in liver. Sex of the fish and soya variety had significant interaction effects on total RNA yield from the whole liver and transcription of SOD-1, suggesting that some diet component affecting males and females differently was present in different levels in the GM and the non-GM soya used in the present study. Dietary DNA sequences were detected in all of the organs analysed, but not all of the samples. Soya and maize rubisco (non-transgenic, multicopy genes) were most frequently detected, while MON810 transgenic DNA fragments were detected in some samples and RRS fragments were not detected. In conclusion, zebrafish shows promise as a model for this application.