Oxidative Stress Enzyme Activities Research Articles

Chitosan and EDTA conjugated graphene oxide antinematodes in Eggplant: Toward improving plant immune response

A new strategy regarding the fabrication of chitosan (CS) or ethylene diamine tetraacetic acid (EDTA) on graphene oxide (GO) was performed. The nematocidal potential against Meloidogyne incognita causing root-knot infection in eggplant was tested. The plant immune response was investigated through measuring the photosynthetic pigments, phenols and proline contents, oxidative stress, and antioxidant enzymes activity. Results indicating that, the treatment by pure GO recorded the most mortality percentages of M. incognita 2nd juveniles followed by GO-CS then GO-EDTA. In vivo greenhouse experiments reveals that, the most potent treatment in reducing nematodes was GO-CS which recorded 85.42%, 75.3%, 55.5%, 87.81%, and 81.32% in numbers of 2nd juveniles, galls, females, egg masses and the developmental stage, respectively. The highest chlorophyll a (104%), chlorophyll b (46%), total phenols (137.5%), and free proline (145.2%) were recorded in GO-CS. The highest malondialdehyde (MDA) value was achieved by GO-EDTA (7.22%), and hydrogen peroxide (H2O2) content by 47.51% after the treatment with pure GO. Treatment with GO-CS increased the activities of catalase (CAT) by 98.3%, peroxidase (POD) by 97.52%, polyphenol oxidase (PPO) by 113.8%, and superoxide dismutase (SOD) by 42.43%. The synthesized nanocomposites increases not only the nematocidal activity but also the plant systematic immune response.

Sublethal and antioxidant effects of six ichthyotoxic algae on early-life stages of the Japanese pearl oyster

Several species of harmful algae form blooms that are detrimental to aquatic organisms worldwide with severe economic loss to several industries. The cosmopolitan ichthyotoxic dinoflagellates and raphidophytes Karenia spp., Chattonella spp., Heterosigma spp., and Margalefidinium (Cochlodinium) polykrikoides are known to cause mass mortalities of fish and invertebrates, and the dinoflagellates Heterocapsa spp. are known to cause mass mortalities of shellfish, notably bivalve molluscs. The species K. mikimotoi, K. papilionacea, H. circularisquama, H. akashiwo, M. polykrikoides, and C. marina form recurrent harmful algal blooms (HAB) in coastal aquaculture areas of shellfish, coinciding with the reproduction seasons of natural and farmed bivalve molluscs. In the present study, their effects on eggs, fertilization, embryos, and three larval stages (D-shaped, umbo and pre-settling larvae) of a model bivalve species, the Japanese pearl oyster, Pinctada fucata martensii, are reported. The harmful algae had differential negative effects on each developmental stage, and had differential effects on larvae depending on their growth stage. Eggs were more affected by M. polykrikoides, K. mikimotoi and H. circularisquama than H. akashiwo and K. papilionacea. Fertilized eggs and developing embryos were more affected by M. polykrikoides and H. circularisquama than K. mikimotoi, K. papilionacea and H. akashiwo. Mortalities as well as abnormalities were not observed in any larval stage; however, motility of d-larvae and umbo larvae was more reduced by H. circularisquama and C. marina, than M. polykrikoides. In elder, 16 day-old larvae, all harmful algae induced a significant decrease in motility with the most severe effect observed during exposures to H. circularisquama, C. marina, H. akashiwo and M. polykrikoides. The superoxidase dismutase activity in larvae was not affected by exposure to any harmful alga; however, 6- and 16-day old larvae experienced a significant increase in GST activity following 48 h of exposures, with higher sensitivity of the elder larvae to C. marina, K. mikimotoi and M. polykrikoides. These results indicate that all tested harmful algae are differentially detrimental to the early-life development of the Japanese pearl oyster, with involvement of oxidative stress. Both M. polykrikoides and H. circularisquama were the most toxic followed by C. marina, K. mikimotoi, H. akashiwo and K. papilionacea. In addition, more developed larvae were most sensitive to these harmful algae in terms of motility-avoidance behavior and oxidative stress response, suggesting that ingestion of the harmful algae might enhance the toxicity of contact-dependent effects and dissolved extracellular compounds. The results also showed that superoxide anions were not associated with effects observed in larvae. Instead cellular detoxification was induced. The differential, stage-specific and growth-specific sublethal effects on bivalve development and recruitment also warrant further investigations of the oxidative stress and antioxidant enzyme activities in larvae of bivalves, to better address the toxicity mechanisms of ichthyotoxic HAB and their impacts on the reproduction, recruitment, and fitness of bivalve molluscs.Summary: The harmful algae Heterocapsa circularisquama, Chattonella marina, Hetrosigma akashiwo, Karenia mikimotoi, K. papilionacea, Margalefidinium (Cochlodinium) polykrikoides differentially affect early life stages of Japanese pearl oyster and activate detoxification enzymes in feeding larvae.

Acute toxicity, accumulation and sublethal effects of four neonicotinoids on juvenile Black Tiger Shrimp (Penaeus monodon)

Neonicotinoid pesticides have been detected in aquatic habitats, and exposure may impact the health of aquatic organisms such as commercially-important crustaceans. Black Tiger Shrimp (Penaeus monodon) is a broadly distributed and high-value shrimp species that rely on estuaries for early life stages. Differences in the acute toxicity and accumulation of different neonicotinoids in tissues of commercial crustaceans have not been widely investigated. This study compared acute toxicity, uptake, and depuration of four neonicotinoids; thiamethoxam, clothianidin, acetamiprid, and imidacloprid, on juvenile P. monodon and their effects on enzyme biomarkers. Acute toxicity (48-h LC50) was determined as 190 μg L−1 (clothianidin), 390 μg L−1 (thiamethoxam), 408 μg L−1 (imidacloprid), and >500 μg L−1(acetamiprid). To assess uptake and elimination, shrimp were exposed to a fixed 5 μg L−1 water concentration for eight days (uptake) or four days of exposure followed by four days of depuration (elimination). Neonicotinoid water and tissue concentrations were measured by liquid chromatography-mass spectrometry following solid-phase extraction and QuEChER extraction respectively. The lower toxicity associated with acetamiprid could be associated with lower accumulation in the tissue, with concentrations remaining below 0.01 μg g−1. The activity of acetylcholinesterase, catalase and glutathione S-transferase in abdominal tissues was determined by spectrophotometric assay, with significant sublethal effects detected for all four neonicotinoids. Depuration reduced the tissue concentration of the active ingredient and reduced the activity of oxidative stress enzymes. Given acetamiprid showed no acute toxicity and reduced impact on the enzymatic activity of P. monodon, it may be an appropriate alternative to other neonicotinoids in shrimp producing areas.

Dietary inclusion of royal jelly modulates gene expression and activity of oxidative stress enzymes in zebrafish

Here we investigated the effects of different levels of royal jelly in zebrafish (Danio rerio) diets [0.0% (D1); 0.1% (D2); 0.4% (D3); 1.6% (D4) vs 6.4% (D5)] on the activity and expression profiles of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glutathione S-transferase. Muscle, liver and kidney tissue samples were obtained from fish fed during 8 weeks. In these tissues, enzyme activity was determined by means of spectrophotometer and gene expression by quantitative real-time PCR. mRNA levels of the enzymes were elevated in almost all diet groups compared to the control (D1). It was determined that enzyme activities were also increased in general by supplementation of royal jelly although some decreases were also observed. However, the significant correlation between gene expression and enzyme activity was not observed in all tissues. It was concluded that main regulation occurs with post-translational modifications although effects at transcriptomic level demonstrated a snap variation.

Humic acid improved germination rate, seedling growth and antioxidant system of pea (<i>Pisum sativum</i> L. var. Alicia) grown in water polluted with CdCl<sub>2</sub>

<abstract> <p>Seeds of pea (<italic>Pisum sativum</italic> L. var. Alicia) were germinated for 5 d by soaking in distilled water or treated with cadmium and/or humic acid (HA). Interaction between humic acid and cadmium was previously discussed. However, the regulation of the humic acid / cadmium interaction during seed germination, the first crucial stage of the plant life cycle, need to be clarified. Seed germination is an important stage of the plant life, which is highly sensitive to surrounding medium changes, since the germinating seed is the first interface of material exchange between plant cycle and environment. Relationships among cadmium stress, HA-treatment, germination rate, and changes in reserve mobilization were studied. Cadmium disrupted the soaking process that was a major event of germination. Moreover, important solutes leakage due to Cd-treatment caused disorder in reserve mobilization from cotyledons to growing embryonic axes. The observed delay in germination rate and seedling growth after Cd-treatment could be explained, partially, by the disturbance in the mobilization of water and nutrients. NADH-and MDA-activities were considered as markers of oxidative stress. they were substantially increased after Cd-treatment compared with controls but decreased in presence of AH. Excessive NADH oxidase activities proved the install of oxidative stress in Cd poisoned seeds. We suggested an antagonist effect of Cd and HA on oxidative stress enzyme activities. Treatment of seeds with Cd and/or AH maintained a high level of guaiacol peroxidase activities during five days. The possible implication of GPOX against Cd toxicity and the improvement of the antioxidant system after AH treatment proved an important implication of these findings during germination.</p> </abstract>

Determination of Oxidative Stress and Antioxidant Enzyme Activity for Physiological Phenotyping During Heavy Metal Exposure.

The overproduction of reactive oxygen species during abiotic stress in plants causes oxidative stress that damage the cell normal functions. For reactive oxygen species (ROS) scavenging, plants developed a defense system with antioxidant enzymes. To measure the oxidative stress and antioxidant enzymes activity spectral enzymatic analysis was used, that is material-intensive, time-consuming, and inefficient. In the present study, the four more studied and main antioxidant enzymatic assays are miniaturized in a 96-well plate system and monitored the activity of enzymes by spectrophotometry. This method has obvious advantages over the standard cuvette analysis method because the miniaturization of the 96-well microplate system decreases the amount of reaction mixture and enzymes extract, thrifts working time, and consumable costs as well.

Effects of the lichen Peltigera canina on Cucurbita pepo spp. pepo grown in soil contaminated by DDTs.

Lichens consisting of a symbiotic association of green algae or cyanobacteria and fungi are found in a variety of environmental conditions worldwide. Terricolous lichens, located in soils, affect the living and lifeless environment of the soil due to their effective secondary metabolite and enzymatic content. Terricolous lichens can increase the biological, chemical, and physical usefulness of soil. However, their effects in ensuring the bioavailability of contaminated soil are not known, especially on soil pollution caused by DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT). This research focuses on the effect of terricolous lichens on zucchini (Cucurbita pepo spp. pepo) grown in soil contaminated by DDTs, utilizing their secondary metabolite and enzymatic contents. Firstly, Peltigera canina, a terricolous lichen species, was added to soil contaminated by DDTs as powdered and intact thallus. After lichen addition to soil, zucchini was planted in. The oxidative stress and antioxidative enzyme activities of zucchini were measured. According to the results, P. canina treatments have a positive effect on the growth and development of zucchini, although oxidative stress was observed. Also, it was determined that powdered application had more effective results than intact thallus application.

Qing-Yu-Mu, an Herbal Formula, Reduces Hepatic Oxidative Stress in Rats Fed a High-Frying Oil Diet and Ameliorates Carbon Tetrachloride-Induced Liver Injury.

Qing-Yu-Mu (QYM) is an herbal formula used to prevent and treat liver disease in Taiwan. In this study, the hepatoprotective effects of QYM were evaluated in two experimental models. First, rats were fed a high-frying oil (FO) diet containing 1.25% QYM for 5 weeks to investigate effects of QYM on hepatic oxidative stress and antioxidant enzyme activities. Then, protective effects of QYM on carbon tetrachloride (CCl4)-induced chronic liver injury were evaluated. Results show that QYM treatment reduced FO diet-induced hepatic lipid peroxidation and reactive oxygen species levels and increased glutathione (GSH) S-transferase activity. A higher reduced GSH/oxidized GSH (GSSG) ratio was observed after QYM treatment. Furthermore, QYM ameliorated CCl4-induced liver injury by reducing the activity of plasma alanine aminotransferase and histological lesions in the liver. QYM also increased the level of hepatic GSH and activities of GSH peroxidase and superoxide dismutase. Finally, chlorogenic acid, chrysophanol, and apigenin were found to be present in relative abundance in QYM. Results show that QYM may exhibit a hepatoprotective effect by reducing oxidative stress and increasing antioxidant activity in the liver.

Plant growth promoting rhizobacteria alleviates drought stress in potato in response to suppressive oxidative stress and antioxidant enzymes activities

Maintenance of plant physiological functions under drought stress is normally considered a positive feature as it indicates sustained plant health and growth. This study was conducted to investigate whether plant growth-promoting rhizobacteria (PGPR) Bacillus subtilis HAS31 has potential to maintain potato growth and yield under drought stress. We analyzed trends of chlorophyll concentration, photosynthesis process, relative water content, osmolytes, antioxidants enzymes and oxidative stress, relative growth rate, tuber and aboveground biomass production in two potato varieties, Santae (drought-tolerant) and PRI-Red (drought-sensitive). Plants of both genotypes were treated with 100 g of HAS31 inoculant at 10 days after germination and exposed to different soil relative water contents (SRWC), including 80 ± 5% (well watered), 60 ± 5% (moderate stress) and 40 ± 5% SRWC (severe stress) for 7 days at tuber initiation stage (30 days after germination). The drought stress reduced plant relative growth rate, biomass production, leaf area, number of leaves and tubers, tuber weight, and final yield. The drought-stressed plants showed decline in chlorophyll contents, membrane stability, leaf relative water contents and photosynthetic rate. Under drought stress, enzymatic activity of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), contents of total soluble sugars, soluble proteins and proline increased. The application of PGPR reduced the impact of drought and maintained higher growth and physio-chemical traits of the plants. The plants with PGPR application showed higher relative growth rate, dry matter production, leaf area, number of tubers, tuber weight and yield as compared to plants without PGPR. The PGPR-HAS31 treated plants maintained higher photosynthetic process, contents of chlorophyll, soluble proteins, total soluble sugars, and enzymatic activities of CAT, POD and SOD as compared to plants without PGPR. The results of the study suggest that plant growth regulators have ability to sustain growth and yield of potato under drought stress by maintaining physiological functions of the plants.

Polyphenolic rich extract of Oroxylum indicum alleviate β-glucuronidase activity via down-regulate oxidative stress: Experimental and computational studies

Oroxilum indicum has an extensive history in the Indian traditional medicine system. The root and stem bark of this plant is well accepted for the treatment, prevention, and cure of various types of diseases. The bark of the plant has a high content of flavonoids and other phenolics, which are known to be responsible for exhibiting various therapeutic effects. The role of O. indicum in liver disease is well known, but until now, the mechanism has not been well studied. In the present study, the stem bark of O. indicum was extracted with ethanol using a hot extraction method and their phyto-chemical analysis was performed. Further, the plant extract was also used to evaluate their role in reducing oxidative stress and β-glucuronidase enzyme activity. The antioxidant study showed that extract has the capability to down-regulate oxidative stress, while β-glucuronidase assay displayed IC50 at 174.36 μg/mL. Additionally, we selected the major polyphenolic phyto-compounds derived from the bark of O. indicum for in silico ADME and docking studies. The ADME study reflected the optimal pharmacokinetic profile of the compounds. However, the docking experiments confirmed that all the selected phyto-compounds have tendency to interact with β-glucuronidase receptor.

Chronic cement dust load induce novel damages in foliage and buds of Malus domestica

Cement industry-derived pollutants appear to play multiple roles in stimulating abiotic stress responses in plants. Cement dust deposition on agriculture fields can affect soils, photosynthesis, transpiration and respiration of plants. Here, we characterised the acute physiological responses of Malus × domestica leaves to different cement dust concentrations. The cement dust was sprinkled over plants daily for 2 months at 10 and 20 g/plant, with 0 g/plant serving as the control. Leaf physiological responses revealed significant increases in oxidative stress and antioxidant enzyme activity levels. Additionally, ascorbic acid, soluble sugar, free amino acid, and pigment levels decreased after exposure to cement dust. Macroscopic morphometric parameters, such as weight, dry matter content, and lengths and widths of leaves and buds, were significantly reduced in the cement-treated groups. A histological analysis of leaves and buds revealed decreased cellular areas, cellular damage, and abridged leaf thickness, while an ion leakage assay confirmed the negative effects on tissue integrity. These results provide evidence that cement dust is a hazardous pollutant that induces abiotic stress responses and has degradative effects on leaf health, pigment and biochemical metabolite levels, and anatomical features. Studies to determine the elemental residues of cement dust present in edible plant parts and the adverse impacts of their consumption on human health are strongly recommended.

Assessment of antioxidant traits and protective action of Egyptian acacia pods extracts against paracetamol-induced liver toxicity in rats.

This study investigates the protective effect of Egyptian acacia pod extracts against overdose of paracetamol-induced liver damage. Egyptian acacia green and brown pods were extracted by mixture of ethanol 80%: HCl (6M) (99:1 v/v). In extracts of green and brown pods, total phenolic content in hydrolyzed ethyl acetate fraction (HEF) at pH 4, was 649.89 and 712.14mg GAE/g while antioxidant activity was 95.55% and 97.35%, both being the highest than any fraction. HEF (pH 4) in brown pods was analyzed by HPLC, there were 22 phenolic compounds rich in ethyl vanillin about 227mg/g and 11 flavonoids rich in catechin 48.70mg/g. A biological experiment was conducted using HEF (pH4) in brown pods against overdose of paracetamol in albino rats induced to hepatotoxicity. Thirty rats were divided into five groups; a control group, a paracetamol group, and the other three received paracetamol plus silymarin or two doses of HEF. Animals were received paracetamol and treated with either silymarin or HEF showed reduced levels of liver (ALT, AST, and ALP) and kidney (urea, creatinine, and uric acid) markers compared with the control group as well as reduction of oxidative stress and increment antioxidant enzyme activity in liver tissue when compared with the paracetamol group. It could be concluded that both HEF and silymarin are considerably high hepatoprotector against paracetamol-induced hepatotoxicity in rats due to their strong antioxidant activity. PRACTICAL APPLICATIONS: Both HEF and silymarin improved liver functions and exerted strong antioxidant activities. This antioxidant activity would have a positive effect against oxidative liver damage caused by parcetamol. Thus, it may be concluded that the liver plasma membranes were protected and the regenerative and reparative capacity of liver by phenolic compound in HEF treatment. The study demonstrated the HEF hepatoprotective activity and recommends using Egyptian acacia pods for treatment of liver disorders.

Evaluation of the biocompatibility of the GSH-coated Ag2S quantum dots in vitro: a perfect example for the non-toxic optical probes

Near-infrared quantum dots (NIR QDs) are promising candidate for the fluorescent probes due to their better penetration depth, long-lived luminescence with size-tunable photoluminescence wavelengths. Glutathione-coated silver sulfide quantum dots (GSH-Ag2S QDs) were synthesized using AgNO3 and Na2S in the aqueous media and they can give reaction with glutathione reductase (GR) and glutathione-s transferase (GST) enzymes as acting substrate analogue in vitro. Investigation of the toxicity of the nanomaterials are necessary to use them in the medical field and biomedical applications. Thus, in this study we investigated biocompatibility of the GSH-Ag2S QDs in vitro using 293T and CFPAC-1 cell lines. Cell viability by MTT assay, light microscopy, fluorescence microscopy, oxidative stress enzyme activities and ICP-MS analysis were performed to evaluate the cytotoxicity and internalization of the GSH-Ag2S QDs. GSH-Ag2S QDs showed great biocompatibility with both cell lines and did not cause imbalance in the oxidative stress metabolism. The ultralow solubility product constant of Ag2S QDs (Ksp = 6.3 × 10-50) prevents release of Ag ions into the biological systems that is in agreement with data obtained by ICP-MS. In conclusion, this data prove potential of GSH-Ag2S QDs as a biocompatible optical probe to be used for the detection and/or targeting of GSH impaired diseases including cancer.

Evaluation of Stress Enzymes Activities and Lipid Peroxidation in Heart Homogenates of Male Albino Rats Following the Administration of Diclofenac

Nonsteroidal anti-inflammatory drugs are associated with an increase in cardiovascular events despite its uses in the therapeutic agent for the management of long- and short-term pain. Over the last years, evidence has accumulated showing that oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Oxidative stress is no longer considered as a simple imbalance between the production and scavenging of reactive oxygen species (ROS), but as a dysfunction of enzymes involved in ROS production. This study investigated the effect of diclofenac on the activity of oxidative stress enzymes as well as formation of lipid peroxidation. Male rats weighing about 100-120 g were divided into four groups: group one (control, feed+water) group two, group three and group four treated with different mg/kg/day of drugs (50 mg/kg/day, 100 mg/kg/day and 150 mg/kg/day) feed and water respectively for 7 days. Analysis on the effect of diclofenac on the activities of stress enzymes such as nicotine adenosine dinucleotide phosphate hydrogenase oxidase (NADPHoxidase), xanthine oxidase(XOD), catalase(CAT), superoxide dismutase(SOD) and Glutathione Peroxidase as well as evaluation of lipid peroxidation by measuring malondialdehyde (MDA) in the heart homogenate were carried out and the result showed a significant increase in each parameter given rise to the production of reactive oxygen species (ROS) if not moderated by the antioxidant defense can lead to cardiac impairment as a result of oxidative stress damage or injury. The result obtained implies that diclofenac (NSAIDs) affects the redox status of vascular tissues (heart tissues).

Prophylactic effect of resveratrol and piperine on pristane-induced murine model of lupus-like disease.

Systemic lupus erythematosus is a multisystem autoimmune disease. Apart from usual treatments, approximately 50% of lupus patients use complementary medicine. Resveratrol is a phytoalexin with various pharmacological properties. We hypothesised that prophylactic treatment with resveratrol may abrogate manifestations in pristane-induced murine model of lupus-like disease and piperine; a bio-enhancer of resveratrol may enhance these properties. The prophylactic effect of resveratrol (25mg/kg body weight: P-Res) alone and in combination with piperine (2.5mg/kg body weight: P-RP) were assessed. P-Res and P-RP were equally efficient in mitigating oxidative stress (enzyme activity of catalase, superoxide dismutase, glutathione peroxidase and level of reduced glutathione, lipid peroxidation, and reactive oxygen species). Inflammation is associated with an increase in inflammatory cytokines. IL-6 was decreased by 71.60% with P-Res, and TNF-α was reduced by 59.70% with P-Res and 62.66% with P-RP (p < 0.05). Prevention of renal pathologies was evident by reduction in creatinine level by P-RP (p < 0.05) and abrogation of proteinuria (P-Res and P-RP). P-RP was efficient in restoring histopathology of liver and lungs and decreased immune complexes in lungs. P-Res proved more beneficial by extenuating lipogranulomas, histopathological manifestations in kidney, liver, and lungs, and eliminating immune complexes in liver and lungs. None of the treatments could regulate auto-antibody formation. Resveratrol decreases the susceptibility of developing pathogenesis in murine model of lupus-like disease. The results also conclude that addressing the bioavailability of resveratrol using it in combination with piperine does not prove more efficacious in preventing lupus-associated pathologies than resveratrol alone.

Doser les enzymes du stress oxydant, oui ou non ?

The determination of oxidative stress enzymes activities is not easy because the presence of dioxygen in environment and by the production of hydrogen peroxide very unstable. The use of indirect redox systems allows more reliable measures, accurate and right. The interest on these measures remains uncertain because the difficulties related to the interpretation of results. A decrease can reveal a default in antioxidant defenses, or depletion; an increase can signal the response to a stress or to a release by cell lysis. Normal values being in a zone of dubiousness reveal as well incapacity to respond to oxidative stress as the beginning of the response. Thus, a number of observers do not recommend anymore the measure of these enzymes, but only markers of oxidation, vitamins and oligo-elements for antioxidant defense related to dietetic or additional measures.

Involvement of oxidative stress in the sensitivity of two algal species exposed to roxithromycin.

Algal species Raphidocelis subcapitata and Chlorella vulgaris are commonly used to test the chemicals with an antibacterial mode of action during marketing authorization process. However, significant differences in the sensitivity toward antibiotic exposure have been reported. The selection of an inappropriate test species would thus underestimate the environmental hazard of target chemicals and pose a potential threat to the ecosystem. Since oxidative stress is a crucial factor determining the inhibition of algal growth, an investigation on oxidative stress and antioxidant defense mechanisms in these two species was performed to explore its roles in species sensitivity. Here, roxithromycin (ROX), a macrolide antibiotic extensively used to treat respiratory, urinary and soft tissue infections, was used for testing. After 7 days exposure to ROX at the low (0.01 mg L-1) and high (0.09 mg L-1) concentrations, R. subcapitata was inhibited while the growth of C. vulgaris was stimulated. We investigated the roles of oxidative stress in algae by measuring the oxidative stress biomarkers (MDA), non-enzymatic antioxidants (GSH), and antioxidant enzymes (SOD, CAT, GP, GST). The results suggested that when the growth of algae is inhibited, MDA content as well as activities of oxidative stress enzymes would increase, and thus, activating the antioxidant system. On the contrary, it was inferred that when the growth is stimulated, MDA content and oxidative stress enzymes activities would decrease.

Trigonella stellata reduced the deleterious effects of diabetes mellitus through alleviation of oxidative stress, antioxidant- and drug-metabolizing enzymes activities

Ethnopharmacological relevanceGenus Trigonella has a history of folkloric medicinal uses in China, Japan, Egypt and India. There are a variety of therapeutic actions of Trigonella including hypocholesterolemia, hypoglycemia, antibacterial, antiviral, anti-inflammatory activities, antioxidants and appetite stimulant. Aim of the studyThe prevalence of diabetes mellitus is increasing annually. The present study aims at investigating the protective effects of Trigonella stellata against the adverse effects of diabetes mellitus through investigation of the changes in phase I & II drug-metabolizing enzyme activities, protein expression of cytochrome P450 isoenzymes [CYP2E1 & 3A4], oxidative stress, antioxidant enzymes as well as histopathology of both liver and kidney tissues. MethodsGC-MS and MALDI-TOF were used to analyze the main constituents of the aqueous and the ethanolic extract of Trigonella stellata. Western immunoblotting technique used to show the protein expression of CYP450 isozymes in different groups. Spectrophotometric- and fluorophotometric techniques were also used for assessment of different hepatic integrity enzymes. Histopathological techniques used to illustrate the changes in the tissues of both livers and kidneys after different treatments. ResultsTrigonelline was found to be the main constituent of both aqueous and ethanolic extract of Trigonella stellata. Administration of the aqueous and/or the ethanolic extracts of Trigonella stellata to the diabetic rats was found to decrease the blood glucose level, the biochemical markers of both liver (transaminases activities, Lactate dehydrogenase, gamma-glutamyl transferase) and the renal functions (urea, creatinine and bilirubin) which were increased in diabetic-treated rats relative to their normal levels. Diabetes mellitus potentially induced the oxidative stress, and also activities of dimethylnitrosamine N-demethylase I, cytochrome c-reductase, ethoxyresourfin O-deethylase, and the total hepatic content of cytochrome P450. On the other hand, the activity of catalase [CAT], superoxide dismutase [SOD], glutathione S-transferase [GST], glutathione reductase [GR], glutathione peroxidase [GPx] and levels of reduced glutathione [GSH] were potentially inhibited in diabetic rats compared to the control rats. However, treatments of diabetic rats with either aqueous and/or ethanolic extracts of Trigonella stellata restored such changes caused by diabetes almost nearly to their normal levels compared to the control group. Supporting the activity of dimethyl nitrosamine N-demethylase I activity, the protein expression of CYP2E1 was also induced in diabetic rats. However, the aqueous extract of Trigonella stellata was more effective than ethanolic extract in restoring the changes in the protein expression of CYP2E. On the other hand, the protein expression of CYP3A4 was markedly decreased in diabetic rats, and this decrease was partially restored to its normal level after treatment of diabetic rats with aqueous and/or ethanolic extracts. In addition, Trigonella stellata extracts alleviated the histopathological changes in livers and kidneys caused by diabetes mellitus. ConclusionIt is concluded that diabetes mellitus induced changes in oxidative stress, phase I & II drug-metabolizing enzymes, and antioxidant enzymes activities, whereas both extracts of Trigonella stellata alleviated such changes. Alterations in cytochrome P450 system should be considered when therapeutic drugs are administered to diabetic patients since most of xenobiotic are mainly metabolized by this system.

Effects of aerobic and resistance exercise on cardiac remodelling and skeletal muscle oxidative stress of infarcted rats.

We compared the influence of aerobic and resistance exercise on cardiac remodelling, physical capacity and skeletal muscle oxidative stress in rats with MI‐induced heart failure. Three months after MI induction, Wistar rats were divided into four groups: Sham; sedentary MI (S‐MI); aerobic exercised MI (A‐MI); and resistance exercised MI (R‐MI). Exercised rats trained three times a week for 12 weeks on a treadmill or ladder. Statistical analysis was performed by ANOVA or Kruskal‐Wallis test. Functional aerobic capacity was greater in A‐MI and strength gain higher in R‐MI. Echocardiographic parameters did not differ between infarct groups. Reactive oxygen species production, evaluated by fluorescence, was higher in S‐MI than Sham, and lipid hydroperoxide concentration was lower in A‐MI than the other groups. Glutathione peroxidase activity was higher in A‐MI than S‐MI and R‐MI. Superoxide dismutase was lower in S‐MI than Sham and R‐MI. Gastrocnemius cross‐sectional area, satellite cell activation and expression of the ubiquitin‐proteasome system proteins did not differ between groups. In conclusion, aerobic exercise and resistance exercise improve functional capacity and maximum load carrying, respectively, without changing cardiac remodelling in infarcted rats. In the gastrocnemius, infarction increases oxidative stress and changes antioxidant enzyme activities. Aerobic exercise reduces oxidative stress and attenuates superoxide dismutase and glutathione peroxidase changes.

Cross talk: Two way allelopathic interactions between toxic Microcystis and Daphnia

Due to eutrophication, freshwater ecosystems frequently experience cyanobacterial blooms, many of which produce bioactive metabolites that can affect vertebrates and invertebrates life traits. Zooplankton are able to develop tolerance as a physiological response to cyanobacteria and their bioactive compounds, however, this comes with energetic cost that in turn influence Daphnia life traits and may impair populations. Vice versa, it has been suggested that Daphnia are able to reduce cyanobacterial dominance until a certain cyanobacterial density; it remains unclear whether Daphnia metabolites alone influence the physiological state and bioactive metabolites production of cyanobacteria. Hence, this study investigates mutual physiological reactions of toxic Microcystis aeruginosa PCC7806 and Daphnia magna. We hypothesize that a) the presence of D. magna will negatively affect growth, increase stress response and metabolites production in M. aeruginosa PCC7806 and b) the presence of M. aeruginosa PCC7806 will negatively affect physiological responses and life traits in D. magna. In order to test these hypotheses experiments were conducted in a specially designed co-culture chamber that allows exchange of the metabolites without direct contact. A clear mutual impact was evidenced. Cyanobacterial metabolites reduced survival of D. magna and decreased oxidative stress enzyme activity. Simultaneously, presence of D. magna did not affect photosynthetic activity. However, ROS increase and tendencies in cell density decrease were observed on the same day, suggesting possible energy allocation towards anti-oxidative stress enzymes, or other protection mechanisms against Daphnia infochemicals, as the strain managed to recover. Elevated concentration of intracellular and overall extracellular microcystin MC-LR, as well as intracellular concentrations of aerucyclamide A and D in the presence of Daphnia, indicating a potential protective or anti-grazing function. However, more research is needed to confirm these findings.