Antioxidant enzyme complex of tissues of the bivalve <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lam. under normal and oxidative-stress conditions: A review

The results of studies of tissue specifics of the enzymatic antioxidant complex of the bivalve Mytilus galloprovincialis Lam. are summarized. It is shown that the highest oxidative load is experienced by gills. The antioxidant complex of gills largely depends on environmental conditions than on the mollusk’s state, which allows this tissue to be used for ecological diagnostics. A decrease in the content of carotenoids in tissue s suppressed the activities of the key enzymes of antiradical defense—superoxide dismutase (SOD) and catalase—and is accompanied by a decrease in the reduced glutathione (GSH) pool. The state of the antioxidant complex of molluscan tissues under conditions of natural (spawning) and artificial (exposure to a cationic surfactant) oxidative stress was studied.     

Gene Expression Profiles Deciphering Rice Phenotypic Variation between Nipponbare (Japonica) and 93-11 (Indica) during Oxidative Stress

Rice is a very important food staple that feeds more than half the world''s population. Two major Asian cultivated rice (Oryza sativa L.) subspecies, japonica and indica, show significant phenotypic variation in their stress responses. However, the molecular mechanisms underlying this phenotypic variation are still largely unknown. A common link among different stresses is that they produce an oxidative burst and result in an increase of reactive oxygen species (ROS). In this study, methyl viologen (MV) as a ROS agent was applied to investigate the rice oxidative stress response. We observed that 93-11 (indica) seedlings exhibited leaf senescence with severe lesions under MV treatment compared to Nipponbare (japonica). Whole-genome microarray experiments were conducted, and 1,062 probe sets were identified with gene expression level polymorphisms between the two rice cultivars in addition to differential expression under MV treatment, which were assigned as Core Intersectional Probesets (CIPs). These CIPs were analyzed by gene ontology (GO) and highlighted with enrichment GO terms related to toxin and oxidative stress responses as well as other responses. These GO term-enriched genes of the CIPs include glutathine S-transferases (GSTs), P450, plant defense genes, and secondary metabolism related genes such as chalcone synthase (CHS). Further insertion/deletion (InDel) and regulatory element analyses for these identified CIPs suggested that there may be some eQTL hotspots related to oxidative stress in the rice genome, such as GST genes encoded on chromosome 10. In addition, we identified a group of marker genes individuating the japonica and indica subspecies. In summary, we developed a new strategy combining biological experiments and data mining to study the possible molecular mechanism of phenotypic variation during oxidative stress between Nipponbare and 93-11. This study will aid in the analysis of the molecular basis of quantitative traits.     

Antioxidant response of the bivalve Pinna nobilis colonised by invasive red macroalgae Lophocladia lallemandii

Invasive species represent a risk to natural ecosystems and a biodiversity hazard. The present work aims to determine the antioxidant enzyme response – superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), the phase II detoxifying enzyme – glutathione S-transferase (GST) – and markers of oxidative damage – thioredoxin reductase (TR) and malondialdehyde (MDA) – in gills and digestive gland of Pinna nobilis and to study the antioxidant response effects in the bivalve colonised by the invasive macroalgae Lophocladia lallemandii. Colonised specimens were collected in a control area without L. lallemandii and another area completely colonised by L. lallemandii. All enzyme activities were found to be present in gills and digestive gland, with some tissue differences. CAT and SOD activities were higher in gills than digestive gland, whereas GST activity and MDA levels were higher in digestive gland. The presence of L. lallemandii induced a significant increase in the activities of antioxidant enzymes in both gills and digestive gland, except for CAT activity in gills. GST and TR activities were also increased in both tissues, as well as the MDA concentration. We can conclude that the presence of L. lallemandii colonising P. nobilis induces a biological stress and oxidative damage to the fan mussel.     

Physiological and metabolic adjustments of Hoplosternum littorale (Teleostei,Callichthyidae) during starvation

All animals face the possibility of limitations in food resources that could ultimately lead to mortality caused by starvation. The primary goal of this study was to characterize the various physiological strategies that allow fish to survive starvation. A multiparametric approach, including morphological biomarkers, blood plasma metabolites, oxidative stress and energy reserves, was used to assess starvation effects on the fish Hoplosternum littorale. Adult specimens were maintained at four experimental groups: control (fed ad libitum), and starved (not fed) fish for 7 and 28 days. Significant changes were observed not only after 28 days, but also after 7 days of starvation. In the shorter period, the hepatosomatic index as well as plasma triglycerides and glucose were significantly lower in starved fish than in the control ones. These results were accompanied by reduced lipid, glycogen and protein reserves in liver and diminished glycogen content in muscle, suggesting the need of these macromolecules as fuel sources. In addition, increased antioxidant enzyme activities were observed in gills, without evidence of oxidative stress in any of the evaluated tissues. Most significant differences were found in 28-days starved fish: total body weight together with the hepatosomatic index was lower when compared to control fish. The plasmatic metabolites tested (glucose, triglyceride, cholesterol and protein), all energy reserves in liver and glycogen content in muscle decreased in 28-days starved fish. Lipid oxidative damage was reported in liver, kidney and brain, and antioxidant enzymes (GST, GR, GPx and CAT) were activated in gills. According to the multivariate analysis, oxidative stress markers and metabolic parameters were key biomarkers that contributed in separating starved from fed fish. Our study allowed an integrated assessment of the fish response to this particular condition.     

Investigation of Cadmium-Induced Genotoxicity and Oxidative Stress Response in Indian Major Carp,Labeo rohita

We investigated genotoxicity and oxidative stress in the gills of Labeo rohita exposed to 33.6, 67.1, and 100.6 mg L^–1of cadmium chloride at 96 h. Genotoxicity was assessed using single cell gel electrophoresis whereas oxidative stress was monitored through lipid peroxidation induction and antioxidant response parameters, namely reduced glutathione (GSH), glutathione peroxidase, glutathione-S-transferase, superoxide dismutase, and catalase (CAT) activities. Significant (p < .05) effect of both concentration and time of exposure was observed on the extent of DNA damage in treated fish. Similarly, malondialdehyde content, level of GSH, and activities of antioxidant enzymes were significantly elevated in treated groups, except CAT. The increased DNA damage and lipid peroxidation (LPO) content along with fluctuation in antioxidant defense system in fish indicated the interaction of cadmium (Cd) with DNA repair processes and production of reactive oxygen species. Thus, Cd is liable for induction of LPO, alteration of antioxidant defenses, and DNA damage in gills of L. rohita.     

Analysis of Phaseolus vulgaris Response to Its Association with Trichoderma harzianum (ALL-42) in the Presence or Absence of the Phytopathogenic Fungi Rhizoctonia solani and Fusarium solani

The present study was carried out to evaluate the ability of Trichoderma harzianum (ALL 42-isolated from Brazilian Cerrado soil) to promote common bean growth and to modulate its metabolism and defense response in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani using a proteomic approach. T. harzianum was able to promote common bean plants growth as shown by the increase in root/foliar areas and by size in comparison to plants grown in its absence. The interaction was shown to modulate the expression of defense-related genes (Glu1, pod3 and lox1) in roots of P. vulgaris. Proteomic maps constructed using roots and leaves of plants challenged or unchallenged by T. harzianum and phytopathogenic fungi showed differences. Reference gels presented differences in spot distribution (absence/presence) and relative volumes of common spots (up or down-regulation). Differential spots were identified by peptide fingerprinting MALDI-TOF mass spectrometry. A total of 48 identified spots (19 for leaves and 29 for roots) were grouped into protein functional classes. For leaves, 33%, 22% and 11% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. For roots, 17.2%, 24.1% and 10.3% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively.     

利用RNA-seq技术分析淹水胁迫下转BnERF拟南芥差异表达基因

为探究淹水胁迫下BnERF调节的耐淹防御相关途径,应用RNA-seq技术,对淹水6小时后的拟南芥(Arabidopsis thaliana)野生型(WT)和转BnERF株系(E33)幼苗进行基因表达分析。结果表明,淹水3天后,E33表现出较强的耐淹性,地上部生长状况和根系发育均明显强于野生型。E33幼苗未淹水处理时相对于野生型单独上调的基因有9个,4个为膜结合蛋白,其中2个参与MAPK级联途径,其它5个参与氧化胁迫及水分调节途径;与未淹水野生型相比,无论是未淹水处理还是淹水6小时后的E33幼苗中缺氧响应、抗氧化防护及细胞、器官发育相关基因的表达量均上调。另外,淹水6小时后E33的差异基因并未完全覆盖淹水6小时后野生型的差异基因;E33幼苗中缺氧响应、氧化胁迫响应、能量的产生与转变、乙醇代谢途径中的基因以及乙烯响应因子基因的表达量都明显高于野生型。上述结果表明,BnERF直接或间接调节植物的淹水胁迫相关生理代谢途径,参与淹水胁迫的防御过程。     

Dramatic Increase in Glycerol Biosynthesis upon Oxidative Stress in the Anaerobic Protozoan Parasite Entamoeba histolytica

Entamoeba histolytica, a microaerophilic enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. Trophozoites of E. histolytica are exposed to a variety of reactive oxygen and nitrogen species during infection. Since E. histolytica lacks key components of canonical eukaryotic anti-oxidative defense systems, such as catalase and glutathione system, alternative not-yet-identified anti-oxidative defense strategies have been postulated to be operating in E. histolytica. In the present study, we investigated global metabolic responses in E. histolytica in response to H₂O₂- and paraquat-mediated oxidative stress by measuring charged metabolites on capillary electrophoresis and time-of-flight mass spectrometry. We found that oxidative stress caused drastic modulation of metabolites involved in glycolysis, chitin biosynthesis, and nucleotide and amino acid metabolism. Oxidative stress resulted in the inhibition of glycolysis as a result of inactivation of several key enzymes, leading to the redirection of metabolic flux towards glycerol production, chitin biosynthesis, and the non-oxidative branch of the pentose phosphate pathway. As a result of the repression of glycolysis as evidenced by the accumulation of glycolytic intermediates upstream of pyruvate, and reduced ethanol production, the levels of nucleoside triphosphates were decreased. We also showed for the first time the presence of functional glycerol biosynthetic pathway in E. histolytica as demonstrated by the increased production of glycerol 3-phosphate and glycerol upon oxidative stress. We proposed the significance of the glycerol biosynthetic pathway as a metabolic anti-oxidative defense system in E. histolytica.     

Comparative characterization of sweetpotato antioxidant genes from expressed sequence tags of dehydration-treated fibrous roots under different abiotic stress conditions

Drought stress is one of the most adverse conditions for plant growth and productivity. The plant antioxidant system is an important defense mechanism and includes antioxidant enzymes and low-molecular weight antioxidants. Understanding the biochemical and molecular responses to drought is essential for improving plant resistance to water-limited conditions. Previously, we isolated and characterized expressed sequence tags (ESTs) from a full-length enriched cDNA library prepared from fibrous roots of sweetpotato subjected to dehydration stress (Kim et al. in BMB Rep 42:271–276, [5]). In this study, we isolated and characterized 11 sweetpotato antioxidant genes from sweetpotato EST library under various abiotic stress conditions, which included six intracellular CuZn superoxide dismutases (CuZnSOD), ascorbate peroxidase, catalase, glutathione peroxidase (GPX), glutathione-S-transferase, thioredoxin (TRX), and five extracellular peroxidase genes. The expression of almost all the antioxidant genes induced under dehydration treatments occurred in leaves, with the exception of extracellular swPB6, whereas some antioxidant genes showed increased expression levels in the fibrous roots, such as intracellular GPX, TRX, extracellular swPA4, and swPB7 genes. During various abiotic stress treatments in leaves, such as exposure to NaCl, cold, and abscisic acid, several intracellular antioxidant genes were strongly expressed compared with the expression of extracellular antioxidant genes. These results indicated that some intracellular antioxidant genes, especially swAPX1 and CuZnSOD, might be specifically involved in important defense mechanisms against oxidative stress induced by various abiotic stresses including dehydration in sweetpotato plants.     

The potential effects of pomegranate (Punica granatum) juice on carbon tetrachloride-induced nephrotoxicity in rats

The purpose of this study was to evaluate the effect of pomegranate (Punica granatum) in inhibiting and reversing the nephrotoxicity of carbon tetrachloride, a potent oxidative stress inducer which induces cellular kidney damage. Rats were intraperitoneally injected with carbon tetrachloride (2 mL/kg body weight) which produced severe renal tissue damage, as demonstrated by decreased uric acid and dramatic elevation of urea and creatinine. In addition, carbon tetrachloride injection caused oxidative stress in rats, as evidenced by increased lipid peroxidation and nitrite/nitrate (NO _x ) concentrations in the renal tissue, along with a remarkable reduction in superoxide dismutase, catalase, glutathione transferase, glutathione reductase, glutathione peroxidase activities and glutathione content. We suggested that pomegranate juice was able to elevate the antioxidant defense system, clean up free radicals, lessen oxidative damages and protect the kidney against carbon tetrachloride-induced toxicity, thus having a potential protective effect.     

Activity-dependent neuroprotective protein (ADNP)-derived peptide (NAP) ameliorates hypobaric hypoxia induced oxidative stress in rat brain

Hypobaric hypoxia is a socio-economic problem affecting cognitive, memory and behavior functions. Severe oxidative stress caused by hypobaric hypoxia adversely affects brain areas like cortex, hippocampus, basal ganglia, and cerebellum. In the present study, we have investigated the antioxidant and memory protection efficacy of the synthetic NAP peptide (NAPVSIPQ) during long-term chronic hypobaric hypoxia (7, 14, 21 and 28 days, 25,000 ft) in rats. Intranasal supplementation of NAP peptide (2 μg/Kg body weight) improved antioxidant status of brain evaluated by biochemical assays for free radical estimation, lipid peroxidation, GSH and GSSG level. Analysis of expression levels of SOD revealed that NAP significantly activated antioxidant genes as compared to hypoxia exposed rats. We have also observed a significant increased expression of Nrf2, the master regulator of antioxidant defense system and its downstream targets such as HO-1, GST and SOD1 by NAP supplementation, suggesting activation of Nrf2-mediated antioxidant defense response. In corroboration, our results also demonstrate that NAP supplementation improved the memory function assessed with radial arm maze. These cumulative results suggest the therapeutic potential of NAP peptide for ameliorating hypobaric hypoxia-induced oxidative stress.