Activity Of Certain Antioxidant Enzymes Research Articles

Effects of Pre-Harvest Spraying with Salicylic Acid (SA) and Sodium Nitroprusside (SNP) on Storage Quality and Pathogenic Fungal Species in ‘Manaohong’ Cherries

Chinese cherries, with their delightful blend of sourness and sweetness, are highly favored for their taste and nutritional benefits. However, they mature in conditions of high temperatures and rainfall, making them vulnerable to fungal infections which compromise their post-harvest quality. Our research aimed to study the effects of pre-harvest spraying with salicylic acid (SA) and sodium nitroprusside (SNP) on the pathogenic fungi in Manaohong cherries and their subsequent storage quality. We discovered that using SA and SNP at varying fruit development stages preserved fruit hardness, texture, appearance, and respiratory rate during storage, although it did not significantly alter the fruit’s dimensions. Furthermore, this pre-harvest treatment preserved levels of titratable acids, total phenols, and other antioxidants in the cherries, bolstered the activities of certain antioxidant enzymes (SOD, APX), and inhibited the activity of PPO and POD enzymes.Notably, the SA treatment alone demonstrated superior storage performance compared to combined treatments. Our research also identified Alternaria alternata and Colletotrichum godetiae as the primary pathogens in Manaohong cherries. In in vitro experiments, neither SA nor SNP inhibited these fungi’s growth. Consequently, we evaluated 12 pesticides and determined that 5% hexaconazole and 50% benomyl were most effective against these pathogens. Thus, to enhance the shelf life of Manaohong cherries and ensure their post-harvest quality, we recommend a pre-harvest spray of a SA, and combined with 5% hexaconazole and 50% benomyl. This approach not only promises enhanced cherry longevity but also lays a foundational strategy for the flourishing Manaohong Cherry industry.

Unlocking the Antioxidant Potential of White Tea and Osmanthus Flower: A Novel Polyphenol Liquid Preparation and Its Impact on KM Mice and Their Offspring.

White tea, known for its high polyphenol content, boasts impressive antioxidant properties, but its practical applications remain promising. In this study, we successfully developed a liquid polyphenolic preparation (wtofLPP) using white tea and osmanthus flowers, characterized by its rich antioxidant content and favorable rheological properties. This formulation offers a strong foundation for the creation and utilization of innovative antioxidant-rich food products. Notably, wtofLPP significantly enhanced the activity of certain antioxidant enzymes in both KM mice and their offspring, leading to a reduction in malondialdehyde (MDA) levels, prolonged swimming endurance, and a marked increase in levels of active antioxidant compounds. Furthermore, our study highlights that fatigue stress can impact offspring mice, suggesting that oxidative damage in parents may influence their offspring, potentially affecting their genetic function.

L-Argine regulates the proliferation, apoptosis and endocrine activity by alleviating oxidative stress in sheep endometrial epithelial cells

l-arginine (L-Arg) is a semiessential amino acid that plays crucial roles in the reproductive performance of animals. This research aimed to investigate the effect of supplementing L-Arg on endometrial epithelial cells (EECs) of Hu sheep. In vivo, female Hu sheep were randomly divided into three groups: control group (n = 5), nutrient-restricted group (n = 5), and L-Arg supplemented nutrient-restricted group (n = 5). Then, the effect of L-Arg on ovine endometrial growth and antioxidant capacity was assessed. We found that L-Arg supplementation promoted the growth of endometrial ductal gland invaginations (DGI), and alleviated oxidative stress in nutrient-restricted sheep. In order to investigate its mechanism, a H2O2-induced EECs oxidative stress model was established, and roles of L-Arg in EECs oxidation resistance, proliferation, apoptosis and endocrine activity were studied in vitro. Our results showed that L-Arg markedly decreased the release of reactive oxygen species (ROS) and malonaldehyde (MDA), and enhanced the expression and activity of certain antioxidant enzymes in EECs challenged by the H2O2 (p < 0.05). Supplementation of L-Arg significantly reduced the effect of 200 μM H2O2 on the viability of EECs (p < 0.05). In addition, EECs treated with L-Arg significantly alleviated the G0/G1-phase cell cycle arrest, apoptosis, and the inhibition of endometrial growth factors expression caused by H2O2 (p < 0.05). Overall, the results demonstrate that L-Arg performs crucial roles in maintaining the proliferation of ovine EECs, endocrine activity and inhibiting apoptosis through reducing oxidative stress. This study offers a theoretical basis for using L-Arg to improve sheep the uterine function.

Repetitions of Strenuous Exercise Consistently Increase Paraoxonase 1 Concentration and Activity in Plasma of Average-Trained Men.

Objectives Oxidative stress, induced by physical activity, may stimulate the expression, release, and activity of certain antioxidant enzymes. We investigated the effect of three repeated bouts of strenuous exercise on paraoxonase 1 concentration (PON1c) and paraoxonase activity (PON). Methods Eleven average-trained healthy men (age 34.0 ± 5.2 years) performed three strenuous exercise tests on a treadmill separated by 72 hours periods of resting. PON1c, PON, ferric-reducing activity of plasma (FRAP), lipid profile, C-reactive protein concentration (CRP), and lactate concentration were determined in plasma. Results Each exercise bout resulted in similar PON1c, PON, FRAP, and high-density lipoprotein concentration (HDL-C) increments, while PON/HDL-C ratio remained stable in all repetitions. Percentage increments at the bout of each exercise were higher for PON1c (by 64.82% at the first, by 92.9% at the second, and by 77.02% at the third exercise) than for PON (by 6.49% at the first, 10.06% at the second, and by 12.32% at the third exercise). Association was found between preexercise PON and PON1c (r = 0.56, p = 0.029), pre- (r = 0.87, p = 0.00003) and postexercise HDL-C (r = 0.6, p = 0.0002), preexercise PON and cardiovascular fitness level of participants measured as VO2max (r = 0.39, p = 0.026), and postexercise PON and lactate concentration (r = 0.44, p = 0.01). Conclusions PON1c and PON increase during strenuous exercise, yet the effect of exercise on PON1 concentration is more pronounced. PON1 does not show tolerance to physical activity. The enzyme may provide short-term protection from oxidative stress in each exercise bout. PON may depend on exercise load. Cardiovascular fitness levels may be associated with PON1 activity.

Characterization of gfdB, putatively encoding a glycerol 3-phosphate dehydrogenase in Aspergillus nidulans

The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB. Unexpectedly, ΔgfdB strains showed oxidative stress sensitivity in the presence of a series of well-known oxidants including tert-butyl-hydroperoxide (tBOOH), diamide as well as hydrogen peroxide. Moderate sensitivity of the mutant towards the cell wall stress inducing agent CongoRed was also observed. Hence, both Gfd isoenzymes contributed to the environmental stress defence of the fungus but their functions were stress-type-specific. Furthermore, the specific activities of certain antioxidant enzymes, like catalase and glutathione peroxidase, were lower in ΔgfdB hyphae than those recorded in the control strain. As a consequence, mycelia from ΔgfdB cultures accumulated reactive species at higher levels than the control. On the other hand, the specific glutathione reductase activity was higher in the mutant, most likely to compensate for the elevated intracellular oxidative species concentrations. Nevertheless, the efficient control of reactive species failed in ΔgfdB cultures, which resulted in reduced viability and, concomitantly, early onset of programmed cell death in mutant hyphae. Inactivation of gfdB brought about higher mannitol accumulation in mycelia meanwhile the erythritol production was not disturbed in unstressed cultures. After oxidative stress treatment with tBOOH, only mannitol was detected in both mutant and control mycelia and the accumulation of mannitol even intensified in the ΔgfdB strain.

Protective effects of phycocyanin on ischemia/reperfusion liver injuries

In this study, phycocyanin (Pc) extracted from Spirulina platensis was used to evaluate its antioxidants effects after ischemia/reperfusion injury (IRI) using the ex-vivo model of isolated perfused rat liver. The rats were divided into eight groups : Control group, where livers were directly perfused after their removal; Cold Ischemia group (CI), livers were treated in the same way as the control group, except that after their collection, they were stored for 12 h and 24 h in the Krebs Henseleit (KH) preservation solution at 4 °C and Treated group (PHY), livers were preserved in the same way as the preceding group except that the KH solution was enriched with phycocyanin at two different concentrations. Pc, a powerful antioxidant, significantly reduced ischemia/reperfusion injury in the liver. In fact, the addition of phycocyanin to the preservation solution significantly decreased the activity of liver transaminases (AST) and (ALT), alkaline phosphatase (ALP), the rate of lipid peroxidation (MDA) and the activity of certain antioxidant enzymes, essentially glutathione-S-transferase (GST) and glutathione peroxidase (GPx). On the other hand, Pc increases the level of thiol groups in hepatic tissues. In conclusion, the results show the Pc-enriched KH conservation solution is effective in preserving the hepatic graft and protecting it against IRI by acting as a potent antioxidant against the products of oxidative stress.

Photosynthetic Performance and Drought-Induced Changes in Activity of Antioxidative Enzymes in Different Varieties of Vigna radiata

In the present study, we analysed the photosynthetic performance in five varieties of Vigna radiata, viz. vars RMG 268, K-851, RMG 492, RMG 975 and Anand using chlorophyll fluorescence parameters. We observed that var. RMG 268 tended to reach highest effective quantum yield of PSII [∆F/Fm′], maximum apparent electron transport rate [ETRmax] and saturating photosynthetically active photon flux density [PPFDsat], followed by var. K-851. Thus as judged by its photosynthetic performance, ecophysiologically var. RMG 268 seems to be better adapted to the semi-arid environment of the state of Rajasthan, India. On the contrary, var. Anand was least adapted to its environment as indicated by lowest ETRmax, PPFDsat and ΔF/Fm′ values. The activities of certain antioxidant enzymes of Vigna radiata in response to drought were also examined in var. RMG 268 and var. Anand. The increased activities of antioxidant enzymes, presumed to limit cellular damage, were observed in var. RMG 268. Cellular malondialdehyde content signal indicators of lipid peroxidation were much higher in var. Anand compared to var. RMG 268. These data revealed that var. RMG 268 had high resistance to environmental and drought conditions and thus substantiated our results obtained on the basis of plant performance.

Effects of the cyclophilin-type peptidylprolyl cis-trans isomerase from Pyropia yezoensis against hydrogen peroxide-induced oxidative stress in HepG2 cells.

The present study aimed to describe the expression and purification of cyclophilin-type peptidylprolyl cis-trans isomerase (PPI) from the red alga Pyropia yezoensis. The antioxidant activity of the purified protein was also demonstrated, based on its ability to act against oxidative stress in HepG2 human hepatocellular carcinoma cells. HepG2 cells that were treated with recombinant PPI protein exhibited a reduction in the formation of hydrogen peroxide (H2O2)-mediated reactive oxygen species (ROS). In HepG2 cells, treatment of recombinant PPI protein expression diminished H2O2-mediated oxidative stress and restored both the expression and the activity of certain antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and thioredoxin reductase (TRR). CAT, SOD and TRR activities were upregulated by treatment with the purified protein. CAT mRNA expression was significantly increased in HepG2 cells treated with recombinant PPI protein. These enzymes are the first line of antioxidant defense against ROS generated in times of oxidative stress. Accordingly, data from the present study indicate that the recombinant PPI protein is able to regulate the expression of antioxidant enzymes. Recombinant PPI has antioxidant properties that prevent oxidative stress-induced toxicity, enhance cell viability, decrease ROS production and inhibit oxidative damage and mitochondrial dysfunction in HepG2 cells. Therefore, the present study hypothesizes that the recombinant PPI protein has the potential to protect the liver against oxidative stress-induced cell damage and should be considered as an antioxidant.

Hepatoprotective Effect of Ethanolic Extract of Lavandula officinalis L. in Alloxan-Induced Diabetic Rats

Background: Plants have been the basis for medical treatments throughout much of human history. Although the active compounds of many herbal drugs are unknown, they have been widely prescribed by traditional medicine practitioners due to their beneficial effects and low cost. Although the primary feature of diabetes is hyperglycemia, diabetic disease can cause damage in several organs, such as the liver, over the long term. Objectives: The present study was conducted to determine the hepatoprotective activity of Lavandula officinalis L. ethanolic extract (LOE) in alloxan-induced diabetic rats. Materials and Methods: Twenty-eight male Wistar rats (weight 200 - 250 g) were randomly divided into four groups as follows: the healthy control group (HC) received saline (0.9% intraperitoneally [i.p.]) on all experimental days, the diabetic control group (DC) received a single dose of alloxan (120 mg/kg i.p.), the first treatment group (FT) received a single dose of alloxan and then 100 mg/kg of LOE i.p. for 21 days, and the second treatment group (ST) received a single dose of alloxan and then 200 mg/kg LOE i.p. for 21 days. After completion of the experimental period, liver tissue was dissected to measure the activity of certain antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (MDA) by spectrophotometry. Blood samples were collected to measure aspartate transaminase (AST) and alanine transaminase (ALT) in the serum, using commercially available diagnostic kits. Results: This study revealed that intraperitoneal administration of LOE for 21 days provided significant hepatoprotection against alloxan-induced elevation in the serum marker enzymes AST (38%) and ALT (38.65%, P < 0.05), the liver antioxidant enzyme SOD (68.61%, P < 0.01), CAT (41.53%), and liver lipid peroxidation (44.74%, P < 0.05) compared to the DC group. Conclusions: The present study indicated a hepatoprotective effect of LOE in diabetic rats.

Salt acclimation processes in wheat

Young wheat plants (Triticum aestivum L. cv. Mv Béres) were exposed to 0 or 25 mM NaCl for 11 days (salt acclimation). Thereafter the plants were irrigated with 500 mM NaCl for 5 days (salt stress). Irrigating the plants with a low concentration of NaCl successfully led to a reduction in chlorotic symptoms and in the impairment of the photosynthetic processes when the plants were exposed to subsequent high-dose salt treatment. After exposure to a high concentration of NaCl there was no difference in leaf Na content between the salt-acclimated and non-acclimated plants, indicating that salt acclimation did not significantly modify Na transport to the shoots. While the polyamine level was lower in salt-treated plants than in the control, salt acclimation led to increased osmotic potential in the leaves. Similarly, the activities of certain antioxidant enzymes, namely glutathione reductase, catalase and ascorbate peroxidase, were significantly higher in salt-acclimated plants. The results also suggest that while SOS1, SOS2 or NHX2 do not play a decisive role in the salt acclimation processes in young wheat plants; another stress-related gene, WALI6, may contribute to the success of the salt acclimation processes. The present study suggested that the responses of wheat plants to acclimation with low level of salt and to treatment with high doses of salt may be fundamentally different.

Assessment of the Effect of Silicon on Antioxidant Enzymes in Cotton Plants by Multivariate Analysis

Silicon has been extensively researched in relation to the response of plants to biotic and abiotic stress, as an element triggering defense mechanisms which activate the antioxidant system. Furthermore, in some species, adding silicon to unstressed plants modifies the activity of certain antioxidant enzymes participating in detoxifying processes. Thus, in this study, we analyzed the activity of antioxidant enzymes in leaves and roots of unstressed cotton plants fertilized with silicon (Si). Cotton plants were grown in hydroponic culture and added with increasing doses of potassium silicate; then, the enzymatic activity of catalase (CAT), guaiacol peroxidase (GPOX), ascorbate peroxidase (APX), and lipid peroxidation were determined. Using multivariate analysis, we found that silicon altered the activity of GPOX, APX, and CAT in roots and leaves of unstressed cotton plants, whereas lipid peroxidation was not affected. The analysis of these four variables in concert showed a clear differentiation among Si treatments. We observed that enzymatic activities in leaves and roots changed as silicon concentration increased, to stabilize at 100 and 200 mg Si L(-1) treatments in leaves and roots, respectively. Those alterations would allow a new biochemical status that could be partially responsible for the beneficial effects of silicon. This study might contribute to adjust the silicon application doses for optimal fertilization, preventing potential toxic effects and unnecessary cost.

Differential Effects of Ornithine Enantiomers on the Activity of Anti‐oxidant Enzymes, Polyamines Content, and Growth of Tobacco Cells under Osmotic Stresses

Ornithine (Orn) plays an essential role in the metabolism of plant cells through incorporation in polyamines biosynthesis, the urea cycle and nitrogen metabolism. Herein, we show that Orn enantiomers have different effects on anti-oxidant enzymes activities, polyamines and proline biosynthesis and also an alleviation effect of osmotic stresses on tobacco cells. The type of stress has a significant impact on the function of L- and D-Orn for improvement of the stress effect on the cells. Under saline conditions, both enantiomers restored cell growth, though D-Orn was more beneficial to some extent. This was accompanied with a higher biosynthesis of putrescine, proline, and up-regulated activity of certain anti-oxidant enzymes by D-Orn. Under drought stress conditions, a distinct differential behavior emerged and only L-Orn showed an alleviative effect on the cell growth. Regulation of hydrogen peroxide content via the activity of catalase/peroxidase and production of osmolytes, e.g., proline and fructans, was dependent on the type of enantiomers. Activity of anti-oxidant enzymes and production of malondialdehyde from cell membranes were differently regulated following treatment with either Orn enantiomer. The results suggest that management of H2 O2 content is a determining feature of the function of Orn enantiomers in tobacco cells under salinity and drought stress conditions.

Antioxidant activity and expression of catalase gene of (Eustoma grandiflorum L) in response to boron and aluminum

Aluminum (Al) is the most inhibiting factor for plant root elongation in acidic soils. Boron (B) is an essential micronutrient whose deficiency occurs in acid soils because of high leaching. Lisianthus (Eustoma grandiflorum L.) is a plant to which Al seems to be beneficial, but the range of B requirement for its growth is not documented yet. Both Al toxicity and B deficiency result in oxidative stress in certain plants. The present study was aimed to evaluate the effects of B and Al on the activity of antioxidant system of rooted cuttings of lisianthus. The plants were grown in nutrient solution and treated with 0, 0.05 and 0.1mM of boron and 0.88mM of aluminum for 24h. Activity of certain antioxidant enzymes and the contents of non-enzymatic antioxidants were evaluated. The expression of CAT gene was quantified by semi-quantitative RT-PCR technique. Increase activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and increase of flavonoids and anthocyanin contents was observed in the plants which treated with 0.1mM B and 0.88mM Al, compared to those treated with 0 and 0.05mM B. Increase of CAT activity was the most pronounced among antioxidant enzymes and was parallel with increased expression of its gene. The results showed that Al and B (in higher concentration) provide lisianthus plant with reinforced antioxidant system.

Cryo-tolerance of zygotic embryos from recalcitrant seeds in relation to oxidative stress—A case study on two amaryllid species

Oxidative stress is a major component of cryoinjury in plant tissues. This study investigated the ability of recalcitrant (i.e. desiccation sensitive) Amaryllis belladonna L. and Haemanthus montanus Baker zygotic embryos to survive cryopreservation, in relation to oxidative stress. The study also investigated whether glycerol cryoprotection promoted embryo post-cryo survival by protecting enzymic antioxidant activities. Zygotic embryos excised from hydrated stored seeds were subjected to various combinations of rapid dehydration (to < or >0.4gg−1[dmb]), cryoprotection (with sucrose or glycerol), and cooling (either rapidly or slowly), and were thereafter assessed for viability, extracellular superoxide (O2−) production, lipid peroxidation (TBARS) and antioxidant enzyme activities. Short-term hydrated storage of whole seeds was accompanied by O2− production and lipid peroxidation, but O2− levels were lower than in dehydrated and cooled embryos and viability was 100%, possibly associated with the high activities of certain antioxidant enzymes. Partial dehydration and cryoprotection (in H. montanus only) increased O2− production (especially in cryoprotected-dried embryos) and was associated with some viability loss, but this was not correlated with enhanced lipid peroxidation. Cooling was generally accompanied by the greatest increase in O2− production, and with a decline in viability. In A. belladonna only, post-cryo TBARS levels were generally higher than for fresh and pre-conditioned embryos. Partial dehydration and cooling decreased antioxidant activities, but these were consistently less severe in glycerol cryoprotected-dried, as opposed to non-cryoprotected-dried embryos. Post-cryo viability retention for glycerol cryoprotected-dried embryos was significantly higher than for non-cryoprotected-dried embryos, possibly facilitated by relatively low post-drying TBARS levels and high post-drying and post-rewarming activities of some antioxidant enzymes in the former. Pre-conditioning treatments such as glycerol cryoprotection, when used in combination with partial drying, may enhance post-cryo viability retention in recalcitrant zygotic embryos by protecting the activities of certain antioxidant enzymes during pre-conditioning for, and after retrieval from, cryostorage.

Aluminum Affects the Antioxidant Activity of Tobacco Cells and the Expression of Salicylate-Induced Protein Kinase (SIPK)

It has been shown that Aluminum (Al) toxicity results in over-production of reactive oxygen species (ROS). Despite the fact that ROS can induce MAPK activation, no direct genetic evidence has linked ROS-induced MAPK activation with Al toxicity. The effect of Al on the activation of antioxidant systems in connection with the expression of salicylate-induced protein kinase (SIPK), was examined in tobacco cells. Suspension-cultured tobacco cells (Nicotiana tabacum L. cv. ‘Barley 21’) were treated with or without 80 μM Al. Certain parameters related to antioxidant activity were measured. A MAPKK inhibitor (PD98059) was also applied together with or without Al treatments and semi quantitative RT-PCR was applied to show the expression level of the SIPK gene. Treatment with Al rapidly increased the radical scavenging capacity of cells, catalase and superoxide dismutase activities, and expression of the SIPK gene, as compared to the control cells. In the presence of Al + PD98059, a decrease in catalase and superoxide dismutase activities was observed, compared to those cells which were treated only with Al. These results suggested that a short treatment with Al induced the activity of certain antioxidant enzymes in tobacco cells and that this response was mediated by a MAPK signal transduction pathway.

Study of the effect of refinery waste water exposure on Allium cepa's enzymatic antioxidant defense: probing potential biomarkers

The effects of heavy metals, hydrocarbons, and various toxicants present in Mathura Refinery Waste Water (MRWW) on Allium cepa were examined as a model plant system. The study was based on exposure of A. cepa to different concentrations of MRWW and compared to untreated control (exposure of onion bulbs with aquaguard purified water) to determine the total protein content and activities of certain antioxidant enzymes. These enzymes were evaluated for their efficacy to serve as biomarkers of refinery waste water pollution. DNA damaging potential of MRWW was also investigated. Data demonstrated maximal enhancement in ascorbate peroxidase activity subsequent to MRWW insult, although a significant increase in activities was also noted for other enzymes in the following order: superoxide dismutase > glutathione-S-transferase > catalase. This is suggestive of their potency as a biomarker of MRWW toxicity. Increase in activities of monodehydroascorbate reductase (MDHAR; 152%) and deoxyribonuclease (345%) were also found in the A. cepa system as a result of MRWW exposure. In conclusion, A. cepa system might thus serve as an appropriate tool for monitoring water pollution, especially produced by petroleum waste and heavy metals in term of induction of glutathione peroxidase, MDHAR, and deoxyribonuclease activity.

Regulation glutathione synthesizing and regenerating enzymes by xenobiotics in the brain of mice with targeted deletion of the NRF2 transcription factor gene

Basal expression of certain antioxidant enzymes was shown to be lower in the livers of Nrf2(-/-) mice (Hayes et al., 2000). In order to investigate the role of Nrf2 in the regulation of GSH synthesizing and regenerating enzymes in the brain, cytosols from the brains of Nrf2(-/-) mice treated with the antioxidant agents ethoxyquin, oltipraz, kahweol palmitate or indole-3-carbinol were analysed for glutathione content, expression and activity of certain antioxidant enzymes. The analysis enzyme activities indicated reduction of 6 phosphogluconate dehydrogenase and Glutathione reductase activities by almost 14 and 20% in Nrf2 null compared with the wild type control respectively. Treatment with chemopreventive agents increased the levels of these enzymes in Nrf2(-/-) mice brain. But only 6-phosphogluconate dehydrogenase activity was increase in both Nrf2(+/+) and Nrf2(-/-) mice brain. However, deletion of Nrf2 did not affect the protein levels of glutmyl cysteine ligase (GCL) and glutathione synthetase (GS) enzymes. Despite lack of apparent effect of the deficiency of Nrf2 on the levels of proteins of GCL and GS, upon treatment with chemical additives, there was an increase in the level of GSH in both Nrf2(+/+) and Nrf2(-/-) mice brain upon treatment with chemical additives. Keywords: Antioxidant, Beta zipper (bZip) transcription factors Glutamylcysteine Ligase , Glutamylcysteine Ligase Modifier subunit, Glutamylcysteine Ligase Catalytic subunit, Glutathione synthetase , Glutathione peroxidise1 Abbreviation: Nrf1, Nrf2

Relationship between S-methylmethionine treatment and the activities of antioxidant enzymes in maize ( Zea mays L.) leaves at chilling temperatures

S-methylmethionine (SMM) is an important intermediary compound in the sulphur metabolism and has been shown to play a possible role in moderating the damaging effects of low temperature stress. The present work investigated the extent to which SMM is capable of influencing the activity of antioxidant enzymes when the subtropical species maize is exposed to chilling temperatures during the early developmental phase. SMM was found to contribute to the protection of maize seedlings against low (&lt;14°C) temperature stress by enhancing the activity of certain antioxidant enzymes to varying extents, and thus helping to neutralise the reactive oxygen species (ROS) formed at this temperature. Results obtained in a gradient plant growth chamber revealed that, with the exception of catalase, SMM increased the activity of all the antioxidants studied (glutathione reductase, glutathione-S-transferase, guaiacol peroxidase, ascorbate peroxidase), particularly in the lower ranges of the temperature gradient (6–14°C).

Protective Action of Diltiazem Against Cadmium Induced Biochemical Changes in the Brain of Swiss Albino Mice

Intraperitoneal administration of diltiazem (DTZ), half an hour prior to cadmium chloride intoxication, showed the protection of animals from neurological injury. The results reveal that cadmium causes lipid peroxidation (LPx) and inhibits the activity of certain antioxidant enzymes in brain. It elevates acid phosphatase level but decreases alkaline phosphatase, protein and cholesterol levels in brain. Diltiazem given before cadmium chloride intoxication shows an early as well as faster recovery for sustaining the normal concentration of such biochemical constituents in brain. Furthermore, diltiazem inhibits LPx and increases glutathione (GSH) level as it has free radical scavenging tendency. The present study suggests the possible use of diltiazem against cadmium induced toxicity in brain. doi: 10.5214/ans.0972.7531.2005.120302

Exogenous Glutathione Completes the Defense against Oxidative Stress in Haemophilus influenzae

Since they are equipped with several strategies by which they evade the antimicrobial defense of host macrophages, it is surprising that members of the genus Haemophilus appear to be deficient in common antioxidant systems that are well established to protect prokaryotes against oxidative stress. Among others, no genetic evidence for glutathione (gamma-Glu-Cys-Gly) (GSH) biosynthesis or for alkyl hydroperoxide reduction (e.g., the Ahp system characteristic or enteric bacteria) is apparent from the Haemophilus influenzae Rd genome sequence, suggesting that the organism relies on alternative systems to maintain redox homeostasis or to reduce small alkyl hydroperoxides. In this report we address this apparent paradox for the nontypeable H. influenzae type strain NCTC 8143. Instead of biosynthesis, we could show that this strain acquires GSH by importing the thiol tripeptide from the growth medium. Although such GSH accumulation had no effect on growth rates, the presence of cellular GSH protected against methylglyoxal, tert-butyl hydroperoxide (t-BuOOH), and S-nitrosoglutathione toxicity and regulated the activity of certain antioxidant enzymes. H. influenzae NCTC 8143 extracts were shown to contain GSH-dependent peroxidase activity with t-BuOOH as the peroxide substrate. The GSH-mediated protection against t-BuOOH stress is most probably catalyzed by the product of open reading frame HI0572 (Prx/Grx), which we isolated from a genomic DNA fragment that confers wild-type resistance to t-BuOOH toxicity in the Ahp-negative Escherichia coli strain TA4315 and that introduces GSH-dependent alkyl hydroperoxide reductase activity into naturally GSH peroxidase-negative E. coli. Finally, we demonstrated that cysteine is an essential amino acid for growth and that cystine, GSH, glutathione amide, and cysteinylglycine can be catabolized in order to complement cysteine deficiency.