Changes In Antioxidant Levels Research Articles

Estimation of Some Antioxidant Factors in Postmenopausal Iraqi Women with Hypertension

Postmenopausal women with hypertension may be linked with cardiovascular risk factors like visceral obesity. Changes in antioxidant levels and lipid profile are considered risk factors concerning heart disease that arises during postmenopausal. Ninety Iraqi women aged between 53-70 years, sixty women with postmenopausal hypertension, and thirty healthy postmenopausal women were selected as control for this study. Blood samples were taken to measure some antioxidants through enzyme-linked immune sorbent assay (ELISA) and lipid profile by enzymatic technique. Results showed that the mean of catalase levels was significantly lower in patients (257.62±6.99) compared towith the control group (499.30±13.08). Glutathione results were significantly lower in patients (10.99±0.26) compared with the healthy control (39.32±2.03). Cholesterol levels were significantly higher in patients (236.09±1.91), while lower levels were observed in the control group (172.67±4.92). Triglyceride levels were significantly higher both in patients (182.10±2.68) and the healthy group (145.92±5.85). HDL levels were significantly lower in patients (29.91±0.37) compared with the control group (43.02±1.38). VLDL levels were significantly higher in patients (36.49±0.54) compared with the control (29.16±1.17). LDL levels were significantly higher in patients (169.74±2.20) than in the control group (1 00.48±5.41). It can be concluded from the results that antioxidant levels decreased in postmenopausal women than in the control group. Elevation in lipid profile of postmenopausal women was observed compared with the control group.

Effect of low-salinity seawater transient on antioxidant capacity, muscle quality and intestinal microorganism of crucian carp (Carassius auratus gibelio)

Freshwater fish are frequently disliked by consumers due to their fishy odor and loose texture. Therefore, salinity treatment before market release is crucial for improving the muscle quality of freshwater fish. In this study, Carassius auratus gibelio was temporarily reared in low-salinity seawater (6 ppt) for 15 days, and changes of antioxidant levels, muscle texture, and intestinal microbial were determined. After temporary rearing in seawater, the hardness, gumminess, and chewiness of the muscle texture improved, and the relative contents of fishy and fatty odors decreased. This indicated that low-salinity treatment can enhance muscle quality and flavor while reducing fishy odor. According to microbiome research, low-salinity saltwater temporarily reduced the relative abundance of some opportunistic pathogens, such as Vibrio (from 47.61% to 0.1%) and Shewanella (from 15.20% to 5.86%) in the intestinal tract of crucian carp, and increased the relative abundance of beneficial bacteria, such as Sphingomonas (from 2.52% to 28.38%). This study can provide a reference for using low-salinity seawater for temporary rearing to enhance the quality of fish prior to marketing.

Geraniol attenuates oxidative stress and neuroinflammation-mediated cognitive impairment in D galactose-induced mouse aging model.

D-galactose (D-gal) administration was proven to induce cognitive impairment and aging in rodents' models. Geraniol (GNL) belongs to the acyclic isoprenoid monoterpenes. GNL reduces inflammation by changing important signaling pathways and cytokines, and thus it is plausible to be used as a medicine for treating disorders linked to inflammation. Herein, we examined the therapeutic effects of GNL on D-gal-induced oxidative stress and neuroinflammation-mediated memory loss in mice. The study was conducted using six groups of mice (6 mice per group). The first group received normal saline, then D-gal (150 mg/wt) dissolved in normal saline solution (0.9%, w/v) was given orally for 9 weeks to the second group. In the III group, from the second week until the 10th week, mice were treated orally (without anesthesia) with D-gal (150 mg/kg body wt) and GNL weekly twice (40 mg/kg body wt) four hours later. Mice in Group IV were treated with GNL from the second week up until the end of the experiment. For comparison of young versus elderly mice, 4 month old (Group V) and 16-month-old (Group VI) control mice were used. We evaluated the changes in antioxidant levels, PI3K/Akt levels, and Nrf2 levels. We also examined how D-gal and GNL treated pathological aging changes. Administration of GNL induced a significant increase in spatial learning and memory with spontaneously altered behavior. Enhancing anti-oxidant and anti-inflammatory effects and activating PI3K/Akt were the mechanisms that mediated this effect. Further, GNL treatment upregulated Nrf2 and HO-1 to reduce oxidative stress and apoptosis. This was confirmed using 99mTc-HMPAO brain flow gamma bioassays. Thus, our data suggested GNL as a promising agent for treating neuroinflammation-induced cognitive impairment.

Thiol/disulfide homeostasis in patients treated with normobaric or hyperbaric oxygen for carbon monoxide poisoning

ObjectivesWe aimed to determine the value of thiol/disulfide homeostasis (TDH) as an oxidative stress marker in hyperbaric oxygen therapy (HBOT) and normobaric oxygen therapy (NBOT) patients presenting with carbon monoxide poisoning. In addition, we compared the effect of HBOT and NBOT on thiol/disulfide parameters. MethodsThis prospective study included 66 patients and 67 healthy individuals who presented to the emergency department. We evaluated serum native thiol, disulfide, and total thiol levels in 8 patients who received HBOT and 58 who received NBOT. We also compared pre- and post-treatment levels of disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol. ResultsThere was a statistically significant difference between the case and control groups in native thiol and total thiol before NBOT (p < 0.006, p < 0.006). We also found a statistically significant difference between the groups in pre- and post-NBOT levels of native thiol and total thiol (p < 0.002, p < 0.003). However, our comparison of HBOT and NBOT showed no significant difference in the levels of native thiol, total thiol, disulfide, disulfide/native thiol, disulfide/total thiol, or native thiol/total thiol (p < 0.544, p < 0.860, p < 0.644, p < 0.409, p < 0.409, p < 0.409, respectively). ConclusionsAlthough thiol/disulfide parameters increased in patients receiving HBOT or NBOT, changes in antioxidant levels did not differ significantly between NBOT and HBOT patients. This suggests that NBOT and HBOT have similar effects on thiol/disulfide parameters. NBOT alone may be effective in centers that do not have HBOT facilities.

Oxidative Stress and Antioxidant Responses of Phormidium ambiguum and Microcystis aeruginosa Under Diurnally Varying Light Conditions.

Two harmful cyanobacteria species (Phormidium ambiguum and Microcystis aeruginosa) were exposed to diurnal light-intensity variation to investigate their favorable and stressed phases during a single day. The photosynthetically active radiation (PAR) started at 0 µmol·m−2·s−1 (06:00 h), increased by ~25 µmol·m−2·s−1 or ~50 µmol·m−2·s−1 every 30 min, peaking at 300 µmol·m−2·s−1 or 600 µmol·m−2·s−1 (12:00 h), and then decreased to 0 µmol·m−2·s−1 (by 18:00 h). The H2O2 and antioxidant activities were paralleled to light intensity. Higher H2O2 and antioxidant levels (guaiacol peroxidase, catalase (CAT), and superoxidase dismutase) were observed at 600 µmol·m−2·s−1 rather than at 300 µmol·m−2·s−1. Changes in antioxidant levels under each light condition differed between the species. Significant correlations were observed between antioxidant activities and H2O2 contents for both species, except for the CAT activity of P. ambiguum at 300 µmol·m−2·s−1. Under each of the conditions, both species responded proportionately to oxidative stress. Even under maximum light intensities (300 µmol·m−2·s−1 or 600 µmol·m−2·s−1 PAR intensity), neither species was stressed. Studies using extended exposure durations are warranted to better understand the growth performance and long-term physiological responses of both species.

The Efficacy and Safety of GCWB104 (Flos Lonicera Extract) in Functional Dyspepsia: A Single-Center, Randomized, Double-Blind, Placebo-Controlled Study.

Background/AimsThe Flos Lonicera extract GCWB104 has been shown to have significant protective effects against gastritis and gastric ulcers in vivo. The aim of this study was to investigate the efficacy and safety of GCWB104 in subjects with functional dyspepsia (FD).MethodsIn this single-center, double-blind, randomized clinical trial, 92 subjects diagnosed with FD using the Rome III criteria were allocated to either the test group (300 mg of GCWB104, containing 125 mg of Flos Lonicera extract, twice daily) or the placebo group (300 mg placebo, twice daily). The total score improvement on the Gastrointestinal Symptom Rating Scale (GSRS) for individual symptoms, changes in antioxidant levels, changes in dyspepsia-related quality of life according to the Nepean Dyspepsia Index (NDI), and adverse effects were compared before and after 8 weeks of treatment.ResultsThe differences in total GSRS scores and score improvements after 8 weeks of treatment were significant between the GCWB104 and control groups (p=0.0452 and p=0.0486, respectively). Thirteen of 15 individual symptoms on the GSRS improved in the GCWB104 group, while six symptoms improved in the control group. In addition, statistically significant changes in rumbling, loose stool, and stool urgency were observed in the GCWB104 group. Blood 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels, known as antioxidants, showed significant reductions after 8 weeks of administration of GCWB104. There were no adverse events related to treatment with GCWB104.ConclusionsGCWB104 safely contributed to improvements in mild to moderate FD and irritable bowel syndrome symptoms. Antioxidant effects of GCWB104 were also suggested (Clinicaltrials.gov number NCT04008901).

A five-year follow-up study of antioxidants, oxidative stress and polyunsaturated fatty acids in schizophrenia

Oxidative stress and dysregulated antioxidant defence may be involved in the pathophysiology of schizophrenia. In the present study, we investigated changes in antioxidants and oxidative stress from an acute to a later stable phase. We hypothesised that the levels of oxidative markers are increased in schizophrenia compared with healthy controls; change from the acute to the stable phase; and are associated with the levels of membrane polyunsaturated fatty acids (PUFAs) and symptom severity. Fifty-five patients with schizophrenia spectrum disorders, assessed during an acute phase and 5 years later during a stable phase, and 51 healthy controls were included. We measured antioxidants (α-tocopherol, uric acid, albumin and bilirubin), markers of oxidative stress (F2-isoprostane and reactive oxygen metabolites) and membrane fatty acids. Antioxidants and oxidative stress markers were compared in schizophrenia versus healthy controls, adjusting for differences in sex, age and smoking, and changes over time. Associations between symptoms and PUFA were also investigated. In the acute phase, α-tocopherol was significantly higher (p &lt; 0.001), while albumin was lower (p &lt; 0.001) compared with the stable phase. Changes in α-tocopherol were associated with PUFA levels in the acute phase. In the stable phase, schizophrenia patients had higher uric acid (p = 0.009) and lower bilirubin (p = 0.046) than healthy controls. CRP was higher in patients in the stable phase (p &lt; 0.001), and there was no significant change from the acute phase. The present findings of change in antioxidant levels in the acute versus stable phase of schizophrenia the present findings suggest that redox regulation is dynamic and changes during different phases of the disorder.

C60 Fullerenes Diminish Muscle Fatigue in Rats Comparable to N-acetylcysteine or β-Alanine.

The aim of this study is to detect the effects of C60 fullerenes, which possess pronounced antioxidant properties, in comparison with the actions of the known exogenous antioxidants N-acetylcysteine (NAC) and β-Alanine in terms of exercise tolerance and contractile property changes of the m. triceps surae (TS) during development of the muscle fatigue in rats. The electrical stimulation of the TS muscle during four 30 min series in control rats led to total reduction of the muscle contraction force. Furthermore, the effects of prior intraperitoneal (i.p.) or oral C60FAS application and preliminary i.p. injection of NAC or β-Alanine on muscle contraction force under fatigue development conditions is studied. In contrast to control rats, animals with C60FAS, NAC, or β-Alanine administration could maintain a constant level of muscle effort over five stimulation series. The accumulation of secondary products and changes in antioxidant levels in the muscle tissues were also determined after the fatigue tests. The increased levels of lactic acid, thiobarbituric acid reactive substances and H2O2 after stimulation were statistically significant with respect to intact muscles. In the working muscle, there was a significant (p < 0.05) increase in the activity of endogenous antioxidants: reduced glutathione, catalase, glutathione peroxidase, and superoxide dismutase. Treated animal groups showed a decrease in endogenous antioxidant activity relative to the fatigue-induced animals (P < 0.05). Oral C60FAS administration clearly demonstrated an action on skeletal muscle fatigue development similar to the effects of i.p. injections of the exogenous antioxidants NAC or β-Alanine. This creates opportunities to oral use of C60FAS as a potential therapeutic agent. Due to the membranotropic activity of C60 fullerenes, non-toxic C60FAS has a more pronounced effect on the prooxidant-antioxidant homeostasis of muscle tissues in rats.

Oxidative stress and DNA damage in zebrafish liver due to hydroxyapatite nanoparticles-loaded cadmium

This study investigated the acute and sub-acute toxicity responses in zebrafish following their exposure to hydroxyapatite-loaded cadmium nanoparticles (nHAP-Cd). The results indicate that cadmium chloride (Cd2+), 20 nm nHAP-Cd (nHAP20-Cd), and 40 nm nHAP-Cd (nHAP40-Cd) caused toxicity in zebrafish; the toxicity levels were in the following order: Cd2+ > nHAP20-Cd > nHAP40-Cd. Furthermore, nHAP-Cd showed level II grade of acute toxicity in zebrafish; the gradation was done on the guidelines of the Organization for Economic Co-operation and Development 203. We also found that Cd2+ ions and nHAP-Cd affected the malondialdehyde (MDA) levels and membrane permeability of zebrafish livers; these effects were compliant with the changes in antioxidant levels. The results of enzyme assays indicate the following notion: following the exposure of zebrafish to 0.12–0.93 mg/L nHAP-Cd, the activities of peroxidase, superoxide dismutase, and catalase enzymes increased significantly. Moreover, the content of anti-superoxide anion also increased substantially. This increasing trend of enzymatic activity was observed until the concentration of nHAP-Cd reached 1.86 mg/L nHAP-Cd. By increasing the concentration of both Cd2+ and nHAP-Cd, we found that levels of DNA damage had increased substantially in zebrafish liver; this effect was visualized by performing comet assay.

The interaction between antioxidant status and cervical cancer: a case control study.

To compare the antioxidant status of cervical cancer patients with healthy controls and to assess the antioxidant levels before and after radiotherapy or radiochemotherapy. Antioxidant levels (glutathione, glutathione peroxidase, superoxide dismutase, and malondialdehyde) were measured in 35 patients with cervical cancer and 35 age-matched healthy controls. Blood samples were collected twice (before and after treatment) from cervical cancer patients and once from healthy control subjects. In the patient group, pre-radiotherapy glutathione and glutathione peroxidase levels were significantly lower (P <0.01 and P <0.0001, respectively) than the control group. Pre-radiotherapy levels of superoxide dismutase were significantly higher in cancer patients (P <0.01). In general, no difference was observed between pre- and post-radiotherapy antioxidant levels in cancer patients. However, when post-radiotherapy glutathione levels were analyzed, patients who did not respond to treatment had significantly higher levels than those who did respond (P <0.01). Levels of antioxidants significantly differed between the patients with cervical cancer and the controls, and no change in antioxidant levels was observed after treatment. Moreover, further studies evaluating the predictive value of glutathione levels on treatment response are warranted.

Effect of iNOS inhibitor LNMMA along with antibiotics Chloramphenicol or Ofloxacin in murine peritoneal macrophages regulates S.aureus infection as well as inflammation: An invitro study.

Death due to sepsis by S.aureus is rapidly increasing because of their potent weaponries against macrophage mediated killing. Macrophages serve as intracellular reservoirs of S.aureus. Although significant resources have been invested during the last decade in new treatments for sepsis, only antibiotic therapy has failed to improve outcomes. Moreover the host pathogen interaction resulted in host cell death triggering inflammation. So, successful therapy requires amalgamation of therapies to delineate pathogen along with providing protection to host cell. With this idea, LNMMA, the iNOS inhibitor is used along with antibiotics Ofloxacin or Chloramphenicol on S.aureus infected mouse peritoneal macrophage. ROS like H2O2, O2- production has been measured. NO inhibition by iNOS inhibitor and antioxidant levels has been analysed. COX2, TLR2 and iNOS expression along with proinflammatory cytokine level was studied. It was found that the use of iNOS inhibitor LNMMA along with antibiotics not only enhances bacterial clearance but also decreases proinflammatory responses in Staphylococcus aureus infected macrophages. Inhibition of TLR2 as well as COX2 has also been found in combined treatment groups. The use of iNOS inhibitor LNMMA plus Ofloxacin or Chloramphenicol pretreatment enhanced bacterial clearance by increasing ROS. Decreases in NO protect the cell from harmful peroxynitril as well as inflammatory damage by changes in iNOS, COX2 activity along with reduced proinflammatory cytokines like TNFα, IFNγ, IL1-β etc. Changes in antioxidant level has been found. This in-vitro realm of augmented bacterial clearance and regulated inflammation may be considered as a novel and important therapeutic intervention.

Meta‐analysis indicates that oxidative stress is both a constraint on and a cost of growth

Oxidative stress (OS) as a proximate mechanism for life‐history trade‐offs is widespread in the literature. One such resource allocation trade‐off involves growth rate, and theory suggests that OS might act as both a constraint on and a cost of growth, yet studies investigating this have produced conflicting results. Here, we use meta‐analysis to investigate whether increased OS levels impact on growth (OS as a constraint on growth) and whether greater growth rates can increase OS (OS as a cost of growth). The role of OS as a constraint on growth was supported by the meta‐analysis. Greater OS, in terms of either increased damage or reduced levels of antioxidants, was associated with reduced growth although the effect depended on the experimental manipulation used. Our results also support an oxidative cost of growth, at least in terms of increased oxidative damage, although faster growth was not associated with a change in antioxidant levels. These findings that OS can act as a constraint on growth support theoretical links between OS and animal life histories and provide evidence for a growth–self‐maintenance trade‐off. Furthermore, the apparent oxidative costs of growth imply individuals cannot alter this trade‐off when faced with enhanced growth. We offer a starting platform for future research and recommend the use of oxidative damage biomarkers in nonlethal tissue to investigate the growth–OS relationship further.

Highly specific changes in antioxidant levels and lipid peroxidation in Parkinson’s disease and its progression: Disease and staging biomarkers and new drug targets

There is evidence that immune-inflammatory, stress of reactive oxygen and nitrogen species (IO&NS) processes play a role in the neurodegenerative processes observed in Parkinson’s disease (PD). The aim of the present study was to investigate peripheral IO&NS biomarkers in PD. We included 56 healthy individuals and 56 PD patients divided in two groups: early PD stage and late PD stage. Plasma lipid hydroperoxides (LOOH), malondialdehyde (MDA), nitric oxide metabolites (NOx), sulfhydryl (SH) groups, catalase (CAT) activity, superoxide dismutase (SOD) activity, paraoxonase (PON)1 activity, total radical trapping antioxidant parameter (TRAP) and C-reactive protein (CRP) were measured. PD is characterized by increased LOOH, MDA and SOD activity and lowered CAT activity. A combination of five O&NS biomarkers highly significantly predicts PD with a sensitivity of 94.5% and a specificity of 86.8% (i.e., MDA, SOD activity, TRAP, SH-groups and CAT activity). The single best biomarker of PD is MDA, while LOOH and SOD activity are significantly associated with late PD stage, but not early PD stage. Antiparkinson drugs did not affect O&NS biomarkers, but levodopa+carbidopa significantly increased CRP. It is suggested that MDA may serve as a disease biomarker, while LOOH and SOD activity are associated with late PD stage characteristic. New treatments for PD should not only target dopamine but also lipid peroxidation.

Hot water treatment in combination with calcium ascorbate dips increases bioactive compounds and helps to maintain fresh-cut apple quality

Fresh-cut ‘Braeburn’ apple slices were dipped into cold water (4°C for 2min) or hot water (HWT, 48°C or 55°C for 2min) followed by dips into 0 or 6% w/v aqueous calcium ascorbate (CaAsc, 2min, 0°C) and stored in air up to 28 d at 4°C. Microbial counts, changes in browning and sensory acceptance were determined to indicate changes in quality. Changes in antioxidant levels were measured using free radical scavenging activity (DPPH), reducing activity (FRAP), ascorbic acid content (AA) and polyphenolic content (by HPLC). CaAsc dips had a strong impact reducing the browning through increasing the flesh luminosity and hue angle. 6% CaAsc in fresh-cut apples extended the overall acceptability from less than 7 d to 14 d. Immediately after CaAsc treatment, AA content was 5 fold higher (0.25–1.25gkg−1) than those not dipped into CaAsc. However, the combination of HWT treatments and CaAsc dips led to seven fold increased levels of AA inside the apple tissue (0.25–1.85gkg−1) and consequently increased the antioxidant activity. HWT did not increase the AA content when not combined with CaAsc dips. The HWT CaAsc dip extended the overall acceptability to 21 d compared to 14 d for samples not heated but dipped into CaAsc. Shelf life was ultimately limited by sensory quality. At day 28, total plate counts were reduced from 5.3logcfu/g (untreated slices) to 4.6logcfu/g in the 6% CaAsc dips and further to 3.9logcfu/g with the combination of HWT and CaAsc dip. Changes in the content of phenolic compounds with time, HWT and CaAsc dip were generally not significant except for slightly increased quercetin and phloridzin levels and decreased p-coumaric and procyanidins over time. The combination of HWT at 48°C for 2min followed by 6% CaAsc dip would be best for preserving the eating quality of apple slices.

Methionine Containing Antioxidants for Pain in Chronic Pancreatitis: A Systematic Review and Meta-analysis

Methionine Containing Antioxidants for Pain in Chronic Pancreatitis: A Systematic Review and Meta-analysis

Interaction of Carbon Nanomaterial Fullerene (C60) and Microcystin-LR in Gills of Fish Cyprinus carpio (Teleostei: Cyprinidae) Under the Incidence of Ultraviolet Radiation

One of the most widely used carbon nanomaterials is fullerene (C60), a lipophilic organic compound that potentially can behave as a carrier of toxic molecules, enhancing the entry of environmental contaminants in specific organs. Microcystins (MC) are cyanotoxins very toxic for human and environmental health. Several studies showed that exposure to MC or C60 generates reactive oxygen species (ROS) and changes in antioxidant levels. Also, another factor that can come to enhance the toxic potential of both MC and C60 is UVA radiation. Therefore, it was evaluated the effects on oxidative stress parameters of ex vivo co-exposure of MC and C60 (5 mg/l) in gills of the fish Cyprinus carpio under UVA radiation incidence. The results showed that (a) there was a loss of antioxidant capacity after low MC concentration (L, 50 μg/l) + C60 co-exposure under UVA, (b) C60 under UVA decreased glutathione-S-transferase (GST) activity, (c) high MC concentration (H, 200 μg/l) + C60 co-exposure decreased the concentrations of glutathione (GSH) under UVA or in the dark, (d) L under UVA increased lipid peroxidation, and (e) C60 did not cause a higher bioaccumulation of MC in gills. The lowering of GSH in H + C60 co-exposure should compromise MC detoxification mediated by GST, although toxin accumulation is not influenced by C60.

Relationship between oxidative stress and pathological findings in abomasum of infected lambs by Haemonchus contortus

The aim of this study was to evaluate the nitric oxide (NO) levels, and oxidative and antioxidant markers of lambs experimentally and naturally infected by Haemonchus contortus, and its relation to lesions in the abomasum. For experimental study, a total of 14 healthy lambs were divided into two groups with seven animals each. Group A represented the uninfected animals (control), and Group B was formed by infected animals with 15,000 larvae of H. contortus. Blood was collected on days 15, 45, and 75 post-infection (PI) to obtain serum for biochemical analysis: lactate dehydrogenase (LDH), nitrite/nitrate (NOx), advanced oxidation protein products (AOPP), and ferric reducing ability of plasma (FRAP). Parasitological stool examination (eggs per gram of feces – EPG) was performed on days 15, 45, and 75 PI to verify the evolution of the infection. On day 15 PI EPG was negative, but on days 45 and 75 PI the EPG was positive for animals from Group B. In the three periods evaluated it was observed an increase of LDH levels in serum of lambs infected with gastrointestinal nematodes, but on the other hand NOx levels were reduced on the same periods in infected animals. The AOPP and FRAP levels did not differ between groups on days 15 and 45 PI, but increased significantly on day 75 PI in infected lambs. The same variables were studied in 10 lambs naturally infected with helminths, where more than 97% corresponded to H. contortus (hematocrit and EPG values were 18.8±2.5% and 7120±2940, respectively). Similar to the experimental study, the levels of NOx reduced, and the levels of LDH, FRAP, and AOPP increased in serum of this animal associated inflammatory infiltrate in the mucosa of the abomasum. Therefore, during the infection by H. contortus it was observed alterations in oxidative markers, indicators of cell lesion confirmed by histological examination of the abomasum, and consequently there were changes in antioxidant levels, with the purpose of cell protection. We also conclude that helminth infection interferes with the nitric oxide metabolism.

Mineral nutrient imbalance, total antioxidants level and DNA damage in common bean (Phaseolus vulgaris L.) exposed to heavy metals.

The present study aimed to analyze the biological effects induced by bioaccumulation of metals in common bean (Phaseolus vulgaris L.). Effects of mineral nutrient imbalance, total antioxidants level and DNA damage induced by accumulation of heavy metals, were investigated in bean seedlings treated with two selected metal concentrations for 7days. Metal content is analyzed by inductively coupled plasma - atomic emission spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay is used and Random Amplified Polymorphic DNA (RAPD) method was applied for investigation of DNA damages. The increasing metal concentration in the treatment medium changed synchronously metal content in samples, and decreased total antioxidant activity in all samples with exception only for samples treated with Ni and Cd. The obtained "DNA fingerprints" demonstrated that the increasing metal concentrations induced changes in RAPD profiles (disappearance and/or appearance of bands in comparison with untreated control samples). The highest number of missing bands was observed in samples treated with zinc (total 4 bands) and nickel (total 4 bands) at both concentrations. These results suggested that mineral nutrient imbalance is involved in changes of antioxidant levels and DNA damages of the seedlings, which may help to understand the mechanism of metal toxicity in plants.

Revisiting redox-active antioxidant defenses in response to hypoxic challenge in both hypoxia-tolerant and hypoxia-sensitive fish species

It is not known whether changes in antioxidant levels always occur in fish in response to the oxidative stress that usually accompanies a hypoxic challenge. The studies of antioxidant responses to hypoxia in fish have mostly focused on very anoxia-tolerant species and indicate that there is an enhancement of antioxidant defenses. Here we present new data on redox-active antioxidants from three species, which range in their tolerance to hypoxia: the epaulette shark, threespine stickleback, and rainbow trout, together with a compilation of results from other studies that have measured oxidative stress parameters in hypoxia-exposed fish. The results suggest that in general, fish do not show an increase in redox-active antioxidant defense in response to oxidative stress associated with hypoxia. Rather, the changes in antioxidant defenses during hypoxia are very much species- and tissue-specific and are not linked to the level of hypoxia tolerance of the fish species.

Dynamic compartment specific changes in glutathione and ascorbate levels in Arabidopsis plants exposed to different light intensities

BackgroundExcess light conditions induce the generation of reactive oxygen species (ROS) directly in the chloroplasts but also cause an accumulation and production of ROS in peroxisomes, cytosol and vacuoles. Antioxidants such as ascorbate and glutathione occur in all cell compartments where they detoxify ROS. In this study compartment specific changes in antioxidant levels and related enzymes were monitored among Arabidopsis wildtype plants and ascorbate and glutathione deficient mutants (vtc2-1 and pad2-1, respectively) exposed to different light intensities (50, 150 which was considered as control condition, 300, 700 and 1,500 μmol m-2 s-1) for 4 h and 14 d.ResultsThe results revealed that wildtype plants reacted to short term exposure to excess light conditions with the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol and an increased activity of catalase in the leaves. Long term exposure led to an accumulation of ascorbate and glutathione mainly in chloroplasts. In wildtype plants an accumulation of ascorbate and hydrogen peroxide (H2O2) could be observed in vacuoles when exposed to high light conditions. The pad2-1 mutant reacted to long term excess light exposure with an accumulation of ascorbate in peroxisomes whereas the vtc2-1 mutant reacted with an accumulation of glutathione in the chloroplasts (relative to the wildtype) and nuclei during long term high light conditions indicating an important role of these antioxidants in these cell compartments for the protection of the mutants against high light stress.ConclusionThe results obtained in this study demonstrate that the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol is an important reaction of plants to short term high light stress. The accumulation of ascorbate and H2O2 along the tonoplast and in vacuoles during these conditions indicates an important route for H2O2 detoxification under these conditions.