Non-enzymatic Antioxidant Responses Research Articles

Photosynthetic apparatus plays a central role in photosensitive physiological acclimations affecting spinach (Spinacia oleracea L.) growth in response to blue and red photon flux ratios

Relative abundance of blue (B) and red (R) photons in the incident light plays a major role in regulating the morphology and physiology of plants. Many studies have been carried out to determine the R:B photon flux ratio (PFR) required for eliciting desired traits in various plant species. However, studies investigating the impact of R:B PFR on the underlying metabolic events and their mutual interactions are limited. In the present study, spinach (Spinacia oleracea L. cv. All Green) plants were raised in a plant growth chamber under R:B PFRs of 100R:0B, 75R:25B, 50R:50B, 25R:75B and 0R:100B provided by customized light-emitting diode (LED) panels. Data related to plant growth, status of photosynthetic apparatus, nitrogen metabolism, metabolite profile, oxidative stress and antioxidant defense response were collected. A putative mechanistic concept highlighting the interplay between photosynthesis, C- and N-assimilation and oxidative stress response in regulating plant growth under changing R:B PFR has been presented. Steady growth under B and R combined treatments was associated with high chlorophyll content, PSII quantum yield (Fv/Fm, Fv/Fo, ΦPSII) and vitality index (RFd) along with proper C- and N-assimilation. Reduction in non-photochemical quenching (NPQ) and oxidative stress was also observed under 25R:75B to 75R:25B light treatments. Subdued photosynthetic activity under deficiency of B waveband resulted in arrested growth due to suboptimal C- and N-assimilation. Monochromatic B lighting caused damage to the photosynthetic apparatus due to increased photooxidation. Presence of B photons was favorable for eliciting enzymatic and non-enzymatic antioxidant defense responses. However, the antioxidant machinery was unable to ameliorate the excessive oxidative damage under 0R:100B treatment resulting in suboptimal plant growth. Integrity and proper functionality of the photosynthetic apparatus under B and R combined light quality treatments was found to play a pivotal role in coordinating the non-photosynthetic light-sensitive metabolic processes in response to changing R:B PFR for ensuring proper plant growth.

Oxidative stress response to aluminum oxide (Al2O3) nanoparticles in Triticum aestivum

The development of nanotechnologies has increased the amount of manufactured metal oxide nanoparticles in the environment. In the view of nanoparticle dispersion to the environment, assessment of their toxicity becomes very crucial. Aluminum oxide (Al2O3) nanoparticles have wide range of use in industry as well as personal care products. The aim of this study was to evaluate the dose dependent effects of 13-nm-sized Al2O3 nanoparticles on wheat correlating with the appearance of enzymatic and non-enzymatic antioxidant defense response. Wheat roots were exposed to different concentrations of Al2O3 nanoparticles (5, 25 and 50 mg mL−1) for 96 h. The effects of Al2O3 nanoparticles were studied using different parameters such as H2O2 content, superoxide dismutase and catalase activity, lipid peroxidation, total proline, photosynthetic pigment and anthocyanin content. The results indicated that while Al2O3 nanoparticles caused a dose dependent increase in H2O2 content, superoxide dismutase activity, lipid peroxidation and proline contents, the catalase activity was decreased in compare the control. Moreover, total chlorophyll, chlorophyll a, carotenoids and anthocyanin contents reduced in the highest concentration 50 mg mL−1. In conclusion, Al2O3 nanoparticles caused oxidative stress in wheat after 96 h.

Modulation of Oxidative Status by Normoxia and Hypoxia on Cultures of Human Dermal Fibroblasts: How Does It Affect Cell Aging?

Reactive oxygen species (ROS) production in the skin is among the highest compared to other organs, and a clear correlation exists between ROS production and skin aging. Many attempts are underway to reduce oxidative stress in the skin by topical treatment or supplementation with antioxidants/cosmeceuticals, and cultures of human dermal fibroblasts (HDF) are widely used for these studies. Here, we examined the influence of oxygen tension on cell aging in HDF and how this impacted ROS production, the enzymatic and nonenzymatic antioxidant response system, and the efficacy of this defense system in limiting DNA damage and in modulating gene expression of proteins involved in the extracellular matrix, linked to skin aging. We investigated a selection of parameters that represent and reflect the behavior of cellular responses to aging and oxygen tension. Serial passaging of HDF under normoxia (21%) and hypoxia (5%) leads to cell aging as confirmed by β-galactosidase activity, p16 expression, and proliferation rate. However, in HDF under 21% O2, markers of aging were significantly increased compared to those under 5% O2 at matched cell passages despite having lower levels of intracellular ROS and higher levels of CoQ10, total GSH, SOD1, SOD3, and mitochondrial superoxide anion. miRNA-181a, which is known to be upregulated in HDF senescence, was also analyzed, and indeed, its expression was significantly increased in old cells at 21% O2 compared to those at 5% O2. Upregulation of MMP1 and downregulation of COL1A1 along with increased DNA damage were also observed under 21% O2 vs 5% O2. The data highlight that chronic exposure to atmospheric 21% O2 is able to trigger hormetic adaptive responses in HDF that however fail, in the long term, to prevent cellular aging. This information could be useful in further investigating molecular mechanisms involved in adaptation of skin fibroblasts to oxidative stress and may provide useful hints in addressing antiaging strategies.

ATRvD1 Reverts Cigarette Smoke-induced Emphysema by Pro-resolutive and Antioxidant Effects

Chronic inflammation of lung parenchyma caused by prolonged exposure to cigarette smoke triggers emphysema, the main expression of COPD. Emphysema is a progressive and irreversible disease. It has any treatment to prevent its progression or repair the tissue damage. New findings demonstrated that lipid mediators, as resolvins, can act in resolution of inflammation and tissue repair. Thereby, we investigated the possible effects of ATRvD1, an homologue synthetic of resolvin D1, in a murine model of pulmonary emphysema induced by cigarette smoke (CS). C57BL/6 mice were exposed to smoke from 12 cigarettes per day during 60 days, and then treated i.v. with ATRvD1 for further 60 days. Bronchoalveolar lavage and lung tissue were collected for biochemical, histological and western blot analysis. Treatment with ATRVD1 restored the mean linear intercept (Lm) and increased the ratio of elastic fibers/volume density of the alveolar spaces. ATRVD1 also showed an increase in the total number of leukocytes in the BAL mainly by increasing the number of macrophages, related to high levels of IL-10 and low levels of myeloperoxidase. Levels of reactive oxygen species as well as 8-OHDG were lower in the ATRvD1 treated group, accompanied by increased GSH/GSSG ratio and SOD activity and high levels of NOS2. The treatment showed an increase in p-NFkB levels as well as a decrease in NRF2 related to an increase of KEAP1 and to low levels of NQO1. In conclusion, ATRvD1 has a pro-resolutive effect contributing to tissue repair. Some antioxidant action is evident by increasing enzymatic and non-enzymatic antioxidant response in this model being a potent therapeutic agent.

Oxidative stress in the hybrid fish jundiara (Leiarius marmoratus × Pseudoplatystoma reticulatum) exposed to Roundup Original®

The aim of this study was to investigate the effects of Roundup Original®, a glyphosate-based herbicide, against biochemical parameters including thiobarbituric acid-reactive substances (TBARS), protein carbonyl, enzymatic and nonenzymatic antioxidant responses and acetylcholinesterase (AChE) of jundiara fish (Leiarius marmoratus × Pseudoplatystoma reticulatum) at a sublethal concentration of 1.357 mg L−1. Fish exposed to the herbicide for different periods (6–96 h) showed a significant increase of both hepatic and muscular TBARS and protein carbonyl. Enzymatic antioxidant activity was decreased in the liver and brain after 48 h of exposure. Glutathione-S-tranferase (GST) had its levels raised in the brain and gills, probably as a toxicity event response. Non protein thiols (GSH) demonstrated a reduction after 6 and 24 h of exposure in the hepatic tissue, followed by an increase at 48 and 96 h in the same tissue. GSH brain levels, however, increased only after 96 h. AChE activity in muscle decreased for all the times tested (26.5, 45, 38 and 14% for 6, 24, 48 and 96 h respectively), but only at 96 h (34%) in the brain. We found that Roundup Original® is able to trigger important changes in the biochemical parameters tested, showing it can be a potential threat for the health and survival of fish in the environment.

Does Swimming at a Moderate Altitude Favor a Lower Oxidative Stress in an Intensity-Dependent Manner? Role of Nonenzymatic Antioxidants.

Casuso, Rafael A., Jerónimo Aragón-Vela, Gracia López-Contreras, Silvana N. Gomes, Cristina Casals, Yaira Barranco-Ruiz, Jordi J. Mercadé, and Jesus R. Huertas. Does swimming at a moderate altitude favor a lower oxidative stress in an intensity-dependent manner? Role of nonenzymatic antioxidants. High-Alt Med Biol. 18:46-55, 2017.-we aimed to describe oxidative damage and enzymatic and nonenzymatic antioxidant responses to swimming at different intensities in hypoxia. We recruited 12 highly experienced swimmers who have been involved in competitive swimming for at least 9 years. They performed a total of six swimming sessions carried out at low (LOW), moderate (MOD), or high (HIGH) intensity at low altitude (630 m) and at 2320 m above sea level. Blood samples were collected before the session (Pre), after the cool down (Post), and after 15 minutes of recovery (Rec). Blood lactate (BL) and heart rate were recorded throughout the main part of the session. Average velocities did not change between hypoxia and normoxia. We found a higher BL in response to MOD intensity in hypoxia. Plasmatic hydroperoxide level decreased at all intensities when swimming in hypoxia. This effect coincided with a lower glutation peroxidase activity and a marked mobilization of the circulating levels of α-tocopherol and coenzyme Q10 in an intensity-dependent manner. Our results suggest that, regardless of the intensity, no oxidative damage is found in response to hypoxic swimming in well-trained swimmers. Indeed, swimmers show a highly efficient antioxidant system by stimulating the mobilization of nonenzymatic antioxidants.

177 - Non-Enzymatic Antioxidant Response in Postmenopausal Women with Decreased Muscle Strength

Background Menopause is the beginning of aging in woman due to loss of ovarian follicular function that produces an abrupt drop in estrogen levels as well as body and biochemical changes like muscle strength loss and oxidative stress (OS). Objective To determinate OS biomarkers in postmenopausal women with low muscle strength. Methods We carried out a cross-sectional study with 42 premenopausal [PRE] (47.8±1.9 years) and 48 postmenopausal [POS] women (53.9±2.3 years) from Mexico City. We measured as OS biomarkers: plasma lipoperoxides (LPO) by the TBARS assay, serum uric acid (UA) using a Cobas© C111 analyzer, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total plasma antioxidant status (TAS) with Randox kits, and we calculated SOD/GPx ratio and antioxidant gap. Handgrip strength was measured with a dynamometer; also we measured weight and height and we calculated the body mass index (BMI). An alternative cut-off value of handgrip strength <20 kg was defined according the Sarcopenia European consensus. Results We found that PRE women had good strength and 20 (42%) of the POS women had low handgrip strength; 83 (92%) of the all women were obese (BMI >25 kg/m2). LPO levels were higher, and SOD and GPx activities were lower in POS women with low muscle strength compared with PRE women (control group), although only GPx had low activity statistically significant (58.6±2.9 vs. 69.2±.1 U/gHb, p<0.05). Non-enzymatic antioxidants were statistically higher (p<0.05) in POS women with low muscle strength than control group: TAS 1262±48.2 vs. 1147±29.9 μmol/L, UA 296±21.8 vs. 265±9.5 μmol/L, and GAP 502±46.1 vs. 395±28.4 μmol/L. Conclusion Our findings suggest that there is a non-enzymatic antioxidant response in postmenopausal women with decreased muscle strength. This work was supported by grant UNAM-IN224115.

Cattle experimentally infected by Anaplasma marginale: Influence of splenectomy on disease pathogenesis, oxidative profile, and antioxidant status

Bovine anaplasmosis is caused by the obligate intraerythrocytic bacteria Anaplasma marginale. These bacteria are transmitted by tick species such as Rhipicephalus (Boophilus) microplus, blood-sucking insects, and fomites (needles, clippers, and other blood contaminated equipment). During the acute phase of infection, animals may develop fever, anemia, jaundice, and hepatosplenomegaly. The aims of this study are to quantify the bacteremia by quantitative PCR in eight naïve calves experimentally infected by A. marginale [splenectomized (n = 4), and intact/non-splenectomized (n = 4)], and to correlate these findings with markers of oxidative stress on days 0, 8, 15, 21 and 23 post-infection. Complete blood counts (CBC) were performed in both groups. Lipid peroxidation was estimated by quantifying thiobarbituric acid reactive substances (TBARS); and non-enzymatic antioxidants were assessed by erythrocyte content of non-protein thiols (NPSH). There were no significant differences in complete blood counts (CBC) between the two groups. However, both groups had a slight decrease on packet cell volume (PCV), erythrocytes and hemoglobin concentration, as well as an increase in total leukocyte counts due to elevated lymphocytes when comparing pre and post-infection with A. marginale. Progressive increase on TBARS levels and concomitant decrease on NPSH content were observed in all animals, without significant differences between splenectomized and intact animals. A positive correlation between bacteremia and TBARS, and a negative correlation between bacteremia and NPSH were observed in both groups with higher correlation for NPSH in splenectomized animals. A negative correlation between TBARS and NPSH levels was observed in both groups indicating lipid peroxidation without a non-enzymatic antioxidant response. The results of experimental infection by A. marginale in cattle showed that bacteremia has an impact on lipid peroxidation regardless of the splenectomy.

Treatment of oxidative stress in brain of ovariectomized rats with omega-3 and lipoic acid.

Postmenopausal women are often affected by a group of metabolic disorders related to oxidative stress. Alternative treatments that can improve the quality of life of these women have been the subject of recent studies. The objective of this study was to evaluate the response to oxidative stress in the brains of rats following ovariectomy, and to determine enzymatic and nonenzymatic antioxidant responses when the animals received 3 months of dietary supplementation. Ovariectomy produced changes in antioxidant profiles characterized by reductions in glutathione S-transferase activity, H2 O2 consumption, superoxide dismutase activity, and vitamin C levels and increases in protein carbonylation. Docosahexaenoic fatty acid (DHA) supplementation restored these parameters to normal values and increased values of other antioxidants (glutathione peroxidase and total glutathione). However, DHA supplementation also increased protein carbonylation and lipid peroxidation. Eicosapentaenoic acid supplementation produced no changes in antioxidants, but decreased lipid peroxidation. Lipoic acid supplementation increased consumption of H2 O2 and decreased protein carbonylation and lipid peroxidation. These results suggest that the antioxidant response to omega-3 varies in different tissues, and in this study DHA treatment had a prooxidant effect in the brain. Lipoic acid treatment, on the other hand, had a protective effect, reducing markers of oxidative damage.

Response Of Strawberry ‘Selva’ Plants On Foliar Application Of Sodium Nitroprusside (Nitric Oxide Donor) Under Saline Conditions

Abstract This study was conducted to evaluate enzymatic and non-enzymatic antioxidant response of ‘Selva’ strawberry plants on exogenous nitric oxide under saline conditions with respect to time of application. Sodium nitroprusside (SNP), as nitric oxide (NO) source, was applied on the leaves by spray before, simultaneously, or after the initiation of saline stress. Results indicated that salinity and/or SNP at concentrations of 50 and 75 μM caused increase in activity of antioxidant enzymes, such as catalase, superoxide dismutase, glutathione reductase, ascorbate peroxidase and peroxidases as well as leaf content of proline, glycine betaine and total phenolics in comparison to control. Time of NO application was important because the highest levels of catalase and ascorbic peroxidase were in plants pre-treated with SNP one week before the initiation of salinity stress. Plants from these combinations had the highest fruit yield among all saline stressed plants. So, it seems that earlier application of SNP is more effective for an optimised protection against deleterious influence of salinity stress, because pre-treated plants had a sufficient time to develop an appropriate antioxidant response. The application of SNP simultaneously or after exposure of plants to stress conditions, was also helpful in increasing plant tolerance but to a lesser extent.

Impact of TiO₂ nanoparticles on Vicia narbonensis L.: potential toxicity effects.

This work was aimed to provide further information about toxicology of TiO2 nanoparticles (NPs) on Vicia narbonensis L., considering different endpoints. After exposure to TiO2 nanoparticle suspension (mixture of rutile and anatase, size <100 nm) at four different concentrations (0.2, 1.0, 2.0 and 4.0 ‰), the seeds of V. narbonensis were let to germinate in controlled environmental conditions. After 72 h, the extent of the success of the whole process (seed germination plus root elongation) was recorded as the vigour index, an indicator of possible phytotoxicity. After the characterisation of the hydric state of different materials, oxidative stress and enzymatic and nonenzymatic antioxidant responses were considered as indicators of possible cytotoxicity and to assess if damage induced by TiO2 NPs was oxidative stress-dependent. Cytohistochemical detection of in situ DNA fragmentation as genotoxicity endpoint was monitored by TUNEL reaction. The treatments with TiO2 NPs in our system induced phytotoxic effects, ROS production and DNA fragmentation. The nonenzymatic and enzymatic antioxidant responses were gradually and differentially activated and were able to maintain the oxidative damage to levels not significantly different from the control. On the other hand, the results of DNA fragmentation suggested that the mechanisms of DNA repair were not effective enough to eliminate early genotoxicity effects.

Cold-induced changes in antioxidant defenses and reactive oxygen species in eight wild almond species

Introduction: Wild almond species (Prunus spp.) demonstrate a greater resistance to low temperatures due to their antioxidant defenses and so represent valuable germplasm sources for rootstock breeding. Methods: Eight genotypes of wild almond were subjected to two different cold treatments. The enzymatic and non-enzymatic antioxidant responses and the levels of some reactive oxygen species in leaves were measured. Results: The high ascorbate content and high ascorbate peroxidase activity found in some almond species contributed to the decrease in H 2 O 2 . Generally, catalase

Enzymatic and non-enzymatic antioxidant responses of alfalfa leaves and roots under different salinity levels

The effect of increasing NaCl concentrations on biomass, hydrogen peroxide (H2O2), ascorbic acid (ASC), proline and total thiol, and the activity of some antioxidant enzymes in alfalfa (Medicago sativa L. cv. Gara-Yonjeh) were investigated. The dry weights of roots and shoots with increasing NaCl concentrations decreased progressively, and the strongest toxicity was detected at NaCl treatment of 200 mM. Superoxide dismutase (SOD) activity in the leaves increased gradually up to NaCl concentrations of 100, while the higher concentration of NaCl reduced SOD activity in both leaves and roots. The maximum levels of ascorbate peroxidase (APX) activity were increased at 150 mM and 100 mM NaCl in leaves and roots of Gara-Yonjeh, respectively. Peroxidase (POD) activity in roots of Gara-Yonjeh increased (82% at 200 mM) by salinity, while it decreased (43% at 200 mM) in leaves. In contrast, catalase (CAT) activity increased (84% at 200 mM) in leaves, and decreased (57% at 200 mM) in the roots of Gara-Yonjeh. Electrophoresis analysis suggested that different patterns in SOD, CAT and POD isoenzymes depend on NaCl concentrations, and the staining intensities of these isoforms are supported the results obtained from the spectrophotometric determinations. In POD and CAT, activity of isoform III was detected at all concentrations, by a "low-high-low" pattern, with the maximum activity at 50 mM of NaCl. Results imply that the function of antioxidant systems in higher NaCl concentration is responsible for the salt tolerance observed in Gara-Yonjeh.

Adaptation of fungi, including yeasts, to cold environments

A wide range of cold environments exist, with an equally broad variety of fungi and yeasts that have adapted to such environments. These adaptations, which affect membranes, enzymes and other cellular components, such as radical scavenging molecules, display a great potential for exploitation in biotechnology. Alterations have been detected in membrane lipids, with an increase in fatty acid unsaturated bonds that enhance their fluidity. We report new data on the different phospholipid composition in membrane lipids in the same fungal species from both Antarctic and temperate regions. The decrease in temperature causes intracellular oxidative stress by inducing the generation of reactive oxygen species. We report the results of the first analysis of the non-enzymatic antioxidant response and phenolic compound production by an Antarctic strain of Geomyces pannorum. A survey on yeasts from the cryosphere is reported with a focus on their adaptation to a cold environment. Some studies have shown that the number of macrofungi in glacier forefronts rises as deglaciation increases. The survival success of many plants in such areas may be attributed to their mycorrhizal associations. We highlighted the macrofungal biodiversity of some Italian alpine habitats, in which we Inocybe microfastigiata, Laccaria montana and Lactarius salicis-herbaceae were recorded for the first time in Lombardy (Italy).

Photosynthetic impairment caused by manganese toxicity and associated antioxidative responses in perennial ryegrass

Manganese (Mn) toxicity can induce oxidative stress and impair photosynthesis in plants. The activity of antioxidant enzymes such as superoxide dismutase (SOD) is increased in Lolium perenne (perennial ryegrass) in response to Mn toxicity (mainly in tolerant cultivars), but it remains unclear whether non-enzymatic antioxidant compounds may have a role in Mn tolerance. Seedlings of perennial ryegrass cv. Nui (Mn-sensitive) and cv. Kingston (Mn-tolerant) were grown in a greenhouse in nutrient solution at increasing Mn doses over 21 days. Even though both cultivars showed similar Mn uptake, dry weight decreases and lipid peroxidation caused by excess Mn were higher in cv. Nui than in Mn-tolerant Kingston. Maximum quantum yield of photosystem II (PSII) (Fv/Fm) declined only in cv. Nui at the highest Mn dose. Effective quantum yield (Ф PSII), electron transport rate, CO2 assimilation, and total chlorophyll concentration in leaves decreased under excess Mn, particularly in the sensitive cultivar. Interestingly, chlorophyll a/b ratio increased (indicating relatively lower concentration of light-harvesting chlorophyll proteins as an adaptive defence mechanism) with an increase in Mn supply only in cv. Kingston, which partially explained its greater Mn tolerance compared with Nui. Concentration of carotenoids was not directly associated with non-photochemical quenching values, suggesting that ryegrass did not dissipate an excess of absorbed energy under Mn toxicity by this mechanism. At increasing excess Mn, both enzymatic (SOD activity) and non-enzymatic antioxidant responses (radical scavenging ability and phenolic concentration) were enhanced, mainly in Kingston. The enhanced antioxidant response in this cultivar suggests the hypothesis of increased capacity to control Mn-triggered oxidative stress as reflected in the reduced lipid peroxidation.

Anti-oxidant modulation in response to gamma radiation induced oxidative stress in developing seedlings of Psoralea corylifolia L.

The seeds of Psoralea corylifolia L., an important medicinal herb in Indian and Chinese Pharmacopeia were exposed to gamma rays (2.5, 5, 10, 15 and 20 kGy) from Co60 source at dose rate of 1.65 kGy h−1. Enzymatic and non-enzymatic anti-oxidant responses were verified according to the developmental stages and gamma dose applied. Plants grown from seeds exposed to higher gamma doses exhibit higher activity of the antioxidants such as [Ascorbate peroxidase (APX, 1.11.1.1), superoxide dismutase (SOD, 1.15.1.1), glutathione reductase (GR, 1.6.4.2) and MDA content till flowering and declined thereafter. In contrast, CAT (1.11.1.6) activity declined in dose and age dependent manner. The correlation of gamma dose applied and oxidative stress was inferred from the increased enzymes activities and depression in total glutathione pool in seedlings developed from irradiated seeds. Nevertheless, the maintenance of high anti-oxidant capacity, psoralen accumulation seems to be an important strategy during acclimation of P. corylifolia to gamma radiation stress. Pronounced accumulation of psoralen following 15 and 20 kGy at post-flowering stage where oxidative stress is triggered modulates lipid peroxidation and proline accumulation. Further, in psoralen producing plants an increase in psoralen content can be used as a biomarker which specifies plant is under stress.

Time course of oxidant markers and antioxidant defenses in subgroups of amyotrophic lateral sclerosis patients

Oxidative stress markers have been found in nervous and peripheral tissues of familial and sporadic amyotrophic lateral sclerosis patients. Here, we evaluated the activity of some antioxidant enzymes glutathione peroxidase, glutathione reductase and Cu–Zn superoxide dismutase in erythrocyte, the marker of non-enzymatic antioxidant response (total antioxidant status), as well as plasma reactive oxygen species, at the enrolment and during disease progression in 88 patients affected by the sporadic form of amyotrophic lateral sclerosis. Our study has been performed along 72 months by grouping the patients according to the ALS functional rating score or rate of disease progression. Our results showed a significant impairment of erythrocytes glutathione peroxidase activity in all groups of patients that remained low during disease time course. SOD1 activity significantly decreased along disease course in subjects with a more impaired functional status. A decreasing activity of all assayed enzymes was found in patients who have a faster disease progression rate. By this work we have the evidence that different ALS phenotypes present with different profile of enzymatic and non-enzymatic antioxidant response.

Juvenile sea bass (Dicentrarchus labrax L.) enzymatic and non-enzymatic antioxidant responses following 17β-estradiol exposure

In the context of 17beta-estradiol (E2) as an environmental contaminant, this study was designed to test the hypothesis whether it can modulate antioxidant defenses in Dicentrarchus labrax, taking gills as the target organ. Enzymatic (GPX--glutathione peroxidase; CAT--catalase; GR--glutathione reductase; GST--glutathione S-transferase) and non-enzymatic antioxidants (NP-SH--non protein thiols; GSHt--total glutathione) were measured following 10-day exposure to E2 in two different ways: water diluted (WD, 200 or 2,000 ng/L) and intraperitoneally injected (i.p., 0.5 or 5 mg/kg). WD exposure caused a single alteration-CAT increase, whereas i.p. exposure decreased all the enzymatic antioxidants. Similarly, NP-SH and GSHt were reduced by i.p. exposure. Thus, different E2 exposure routes determined clear differences on the assessed responses. Despite gills close contact with water, their defenses were not strongly affected in WD experiment. Differently, i.p. injected fish showed an overall decrease in both enzymatic and non-enzymatic antioxidants, more pronounced at the highest concentration, pointing out the E2 oxidative stress inducing potential in fish.

Combined effect of salicylic acid and salinity on some antioxidant activities, oxidative stress and metabolite accumulation in Phaseolus vulgaris

It has been shown that salicylic acid (SA) acts as an endogenous signal molecule responsible for inducing abiotic stress tolerance in plants. The effect of SA and sodium chloride (NaCl) on growth, metabolite accumulation, oxidative stress and enzymatic and non-enzymatic antioxidant responses on common bean plants (Phaseolus vulgaris, cv. F-15) was studied. Results revealed that either SA or NaCl decrease, shoot, root and total plant dry weights. SA treatments decreased the contents of proline, and reduced forms of ascorbate and glutathione, however, the content of soluble sugars (TSS), thiobarbituric acid-reactive substances (TBARs) and oxidized ascorbate remained unaffected. On the other hand, salinity significantly reduced the levels of endogenous SA but increased the content of proline, soluble sugars, TBARs, ascorbate and glutathione, as well as all increasing the levels of antioxidant enzyme activities assayed, except CAT. The application of SA improved the response of common bean plants to salinity by increasing plant dry weight and decreasing the content of organic solutes (proline and TSS) and damage to the membrane (TBARs). Moreover, SA application under saline conditions decreased the levels of antioxidant enzyme activities POX, APX and MDHAR which could indicate successful acclimatization of these plants to saline conditions.

Antioxidant potential of Ocimum sanctum under growth regulator treatments

In this study, Ocimum sanctum plants were treated with paclobutrazol (PBZ) and Abscissic acid (ABA) to analyze the changes in the enzymatic and non-enzymatic antioxidant responses. Nonenzymatic antioxidants like ascorbic acid decreased in the ABA treated plants. But it increased in the PBZ treated plants. Although both PBZ and ABA treatments considerably increased the -tocopherol content, it was more in the PBZ treated plants. Enzymatic antioxidants like ascorbate peroxidase and superoxide dismutase were also increased by the treatments. Catalase activity was increased by both growth regulators to a significant extent when compared with the control plants. In conclusion, our results indicated that the PBZ and ABA applications at low concentrations could be used as potential tools to increase defense mechanisms in medicinal plants.