Antioxidants

Editorial

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4 pages, 200 KiB

Open AccessEditorial

Enzymatic and Non-Enzymatic Molecules with Antioxidant Function

by Paola Irato and Gianfranco Santovito

Antioxidants 2021, 10(4), 579; https://doi.org/10.3390/antiox10040579 - 9 Apr 2021

Cited by 119 | Viewed by 9159

Abstract

It is well known that the excessive production of reactive oxygen species (ROS) can lead to the peroxidation of membrane lipids, glycation/oxidation/nitration of proteins, inactivation of enzymes, DNA mutation and damage, and other alterations in the subcellular components [...] Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

Research

Jump to: Editorial, Review

17 pages, 3556 KiB

Open AccessArticle

Parallel Molecular Evolution of Catalases and Superoxide Dismutases—Focus on Thermophilic Fungal Genomes

by Katarína Chovanová, Miroslav Böhmer, Andrej Poljovka, Jaroslav Budiš, Jana Harichová, Tomáš Szemeš and Marcel Zámocký

Antioxidants 2020, 9(11), 1047; https://doi.org/10.3390/antiox9111047 - 27 Oct 2020

Cited by 11 | Viewed by 5874

Abstract

Catalases (CAT) and superoxide dismutases (SOD) represent two main groups of enzymatic antioxidants that are present in almost all aerobic organisms and even in certain anaerobes. They are closely interconnected in the catabolism of reactive oxygen species because one product of SOD reaction [...] Read more.

Catalases (CAT) and superoxide dismutases (SOD) represent two main groups of enzymatic antioxidants that are present in almost all aerobic organisms and even in certain anaerobes. They are closely interconnected in the catabolism of reactive oxygen species because one product of SOD reaction (hydrogen peroxide) is the main substrate of CAT reaction finally leading to harmless products (i.e., molecular oxygen and water). It is therefore interesting to compare the molecular evolution of corresponding gene families. We have used a phylogenomic approach to elucidate the evolutionary relationships among these two main enzymatic antioxidants with a focus on the genomes of thermophilic fungi. Distinct gene families coding for CuZnSODs, FeMnSODs, and heme catalases are very abundant in thermophilic Ascomycota. Here, the presented results demonstrate that whereas superoxide dismutase genes remained rather constant during long-term evolution, the total count of heme catalase genes was reduced in thermophilic fungi in comparison with their mesophilic counterparts. We demonstrate here, for the newly discovered ascomycetous genes coding for thermophilic superoxide dismutases and catalases (originating from our sequencing project), the expression patterns of corresponding mRNA transcripts and further analyze translated protein sequences. Our results provide important implications for the physiology of reactive oxygen species metabolism in eukaryotic cells at elevated temperatures. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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13 pages, 2377 KiB

Open AccessArticle

The Industrial Organism Corynebacterium glutamicum Requires Mycothiol as Antioxidant to Resist Against Oxidative Stress in Bioreactor Cultivations

by Fabian Stefan Franz Hartmann, Lina Clermont, Quach Ngoc Tung, Haike Antelmann and Gerd Michael Seibold

Antioxidants 2020, 9(10), 969; https://doi.org/10.3390/antiox9100969 - 9 Oct 2020

Cited by 13 | Viewed by 4281

Abstract

In aerobic environments, bacteria are exposed to reactive oxygen species (ROS). To avoid an excess of ROS, microorganisms are equipped with powerful enzymatic and non-enzymatic antioxidants. Corynebacterium glutamicum, a widely used industrial platform organism, uses mycothiol (MSH) as major low molecular weight [...] Read more.

In aerobic environments, bacteria are exposed to reactive oxygen species (ROS). To avoid an excess of ROS, microorganisms are equipped with powerful enzymatic and non-enzymatic antioxidants. Corynebacterium glutamicum, a widely used industrial platform organism, uses mycothiol (MSH) as major low molecular weight (LMW) thiol and non-enzymatic antioxidant. In aerobic bioreactor cultivations, C. glutamicum becomes exposed to oxygen concentrations surpassing the air saturation, which are supposed to constitute a challenge for the intracellular MSH redox balance. In this study, the role of MSH was investigated at different oxygen levels (pO₂) in bioreactor cultivations in C. glutamicum. Despite the presence of other highly efficient antioxidant systems, such as catalase, the MSH deficient ΔmshC mutant was impaired in growth in bioreactor experiments performed at pO₂ values of 30%. At a pO₂ level of 20%, this growth defect was abolished, indicating a high susceptibility of the MSH-deficient mutant towards elevated oxygen concentrations. Bioreactor experiments with C. glutamicum expressing the Mrx1-roGFP2 redox biosensor revealed a strong oxidative shift in the MSH redox potential (E_MSH) at pO₂ values above 20%. This indicates that the LMW thiol MSH is an essential antioxidant to maintain the robustness and industrial performance of C. glutamicum during aerobic fermentation processes. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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15 pages, 2323 KiB

Open AccessArticle

Molecular Characterization, Protein–Protein Interaction Network, and Evolution of Four Glutathione Peroxidases from Tetrahymena thermophila

by Diana Ferro, Rigers Bakiu, Sandra Pucciarelli, Cristina Miceli, Adriana Vallesi, Paola Irato and Gianfranco Santovito

Antioxidants 2020, 9(10), 949; https://doi.org/10.3390/antiox9100949 - 2 Oct 2020

Cited by 17 | Viewed by 3347

Abstract

Glutathione peroxidases (GPxs) form a broad family of antioxidant proteins essential for maintaining redox homeostasis in eukaryotic cells. In this study, we used an integrative approach that combines bioinformatics, molecular biology, and biochemistry to investigate the role of GPxs in reactive oxygen species [...] Read more.

Glutathione peroxidases (GPxs) form a broad family of antioxidant proteins essential for maintaining redox homeostasis in eukaryotic cells. In this study, we used an integrative approach that combines bioinformatics, molecular biology, and biochemistry to investigate the role of GPxs in reactive oxygen species detoxification in the unicellular eukaryotic model organism Tetrahymena thermophila. Both phylogenetic and mechanistic empirical model analyses provided indications about the evolutionary relationships among the GPXs of Tetrahymena and the orthologous enzymes of phylogenetically related species. In-silico gene characterization and text mining were used to predict the functional relationships between GPxs and other physiologically-relevant processes. The GPx genes contain conserved transcriptional regulatory elements in the promoter region, which suggest that transcription is under tight control of specialized signaling pathways. The bioinformatic findings were next experimentally validated by studying the time course of gene transcription and enzymatic activity after copper (Cu) exposure. Results emphasize the role of GPxs in the detoxification pathways that, by complex regulation of GPx gene expression, enable Tethraymena to survive in high Cu concentrations and the associated redox environment. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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16 pages, 2501 KiB

Open AccessArticle

Catalase T-Deficient Fission Yeast Meiocytes Show Resistance to Ionizing Radiation

by Razan Muhtadi, Alexander Lorenz, Samantha J. Mpaulo, Christian Siebenwirth and Harry Scherthan

Antioxidants 2020, 9(9), 881; https://doi.org/10.3390/antiox9090881 - 17 Sep 2020

Cited by 2 | Viewed by 3099

Abstract

Environmental stress, reactive oxygen species (ROS), or ionizing radiation (IR) can induce adverse effects in organisms and their cells, including mutations and premature aging. DNA damage and its faulty repair can lead to cell death or promote cancer through the accumulation of mutations. [...] Read more.

Environmental stress, reactive oxygen species (ROS), or ionizing radiation (IR) can induce adverse effects in organisms and their cells, including mutations and premature aging. DNA damage and its faulty repair can lead to cell death or promote cancer through the accumulation of mutations. Misrepair in germ cells is particularly dangerous as it may lead to alterations in developmental programs and genetic disease in the offspring. DNA damage pathways and radical defense mechanisms mediate resistance to genotoxic stresses. Here, we investigated, in the fission yeast Schizosaccharomyces pombe, the role of the H₂O₂-detoxifying enzyme cytosolic catalase T (Ctt1) and the Fe²⁺/Mn²⁺ symporter Pcl1 in protecting meiotic chromosome dynamics and gamete formation from radicals generated by ROS and IR. We found that wild-type and pcl1-deficient cells respond similarly to X ray doses of up to 300 Gy, while ctt1∆ meiocytes showed a moderate sensitivity to IR but a hypersensitivity to hydrogen peroxide with cells dying at >0.4 mM H₂O₂. Meiocytes deficient for pcl1, on the other hand, showed a resistance to hydrogen peroxide similar to that of the wild type, surviving doses >40 mM. In all, it appears that in the absence of the main H₂O₂-detoxifying pathway S. pombe meiocytes are able to survive significant doses of IR-induced radicals. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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18 pages, 2736 KiB

Open AccessArticle

Effects of Moringa oleifera Leaf Extract on Diabetes-Induced Alterations in Paraoxonase 1 and Catalase in Rats Analyzed through Progress Kinetic and Blind Docking

by Erick Sierra-Campos, Mónica Valdez-Solana, Claudia Avitia-Domínguez, Mara Campos-Almazán, Ismael Flores-Molina, Guadalupe García-Arenas and Alfredo Téllez-Valencia

Antioxidants 2020, 9(9), 840; https://doi.org/10.3390/antiox9090840 - 8 Sep 2020

Cited by 16 | Viewed by 6037

Abstract

In our study, we aimed to evaluate the effects of Moringa oleifera leaves extract on rat paraoxonase 1 (rPON1) and catalase (rCAT) activities in alloxan-induced diabetic rats. Our study included three groups; group C (control, n = 5); group D (diabetic, n = [...] Read more.

In our study, we aimed to evaluate the effects of Moringa oleifera leaves extract on rat paraoxonase 1 (rPON1) and catalase (rCAT) activities in alloxan-induced diabetic rats. Our study included three groups; group C (control, n = 5); group D (diabetic, n = 5); and group DM (M. oleifera extract-supplemented diabetic rats, n = 5). Daily oral administration of M. oleifera extract at 200 mg/kg doses produced an increase in endogenous antioxidants. Serum rPON1 (lactonase) and liver cytosol catalase activities were determined by a spectrophotometric assay using progress curve analysis. We found a decrease in the Vm value of rPON1 in diabetic rats, but dihydrocoumarin (DHC) affinity (Km) was slightly increased. The value of Vm for the DM group was found to be reduced approximately by a factor of 3 compared with those obtained for group C, whereas Km was largely changed (96 times). Catalase activity was significantly higher in the DM group. These data suggest that the activation of rPON1 and rCAT activities by M. oleifera extracts may be mediated via the effect of the specific flavonoids on the enzyme structure. In addition, through molecular blind docking analysis, rPON1 was found to have two binding sites for flavonoids. In contrast, flavonoids bound at four sites in rCAT. In conclusion, the data suggest that compounds from M. oleifera leaves extract were able to influence the catalytic activities of both enzymes to compensate for the changes provoked by diabetes in rats. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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11 pages, 1719 KiB

Open AccessArticle

Platelet-Rich Fibrin Can Neutralize Hydrogen Peroxide-Induced Cell Death in Gingival Fibroblasts

by Zahra Kargarpour, Jila Nasirzade, Francesca Di Summa, Layla Panahipour, Richard J. Miron and Reinhard Gruber

Antioxidants 2020, 9(6), 560; https://doi.org/10.3390/antiox9060560 - 26 Jun 2020

Cited by 18 | Viewed by 3983

Abstract

Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells [...] Read more.

Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells were exposed to hydrogen peroxide with and without lysates obtained from PRF membranes, PPP, heated PPP (75 °C for 10 min), and the buffy coat. Cell viability was examined by trypan blue staining, live-dead staining, and formazan crystal formation. Cell apoptosis was assessed by cleaved caspase-3 Western blot analysis. Reverse transcription-quantitative polymerase chain reaction (RT-PCR) was utilized to determine the impact of PRF lysates on the expression of catalase in fibroblasts. It was reported that lysates from PRF, PPP, and the buffy coat—but not heated PPP—abolished the hydrogen peroxide-induced toxicity in gingival fibroblasts. Necrosis was confirmed by a loss of membrane integrity and apoptosis was ruled out by the lack of cleavage of caspase-3. Aminotriazole, an inhibitor of catalase, reduced the cytoprotective activity of PRF lysates yet blocking of glutathione peroxidase by mercaptosuccinate did not show the same effect. PRF lysates had no impact on the expression of catalase in gingival fibroblasts. These findings suggest that PRF, PPP, and the buffy coat can neutralize hydrogen peroxide through the release of heat-sensitive catalase. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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14 pages, 2466 KiB

Open AccessArticle

A Novel and Potentially Multifaceted Dehydroascorbate Reductase Increasing the Antioxidant Systems is Induced by Beauvericin in Tomato

by Martina Loi, Silvana De Leonardis, Giuseppina Mulè, Antonio F. Logrieco and Costantino Paciolla

Antioxidants 2020, 9(5), 435; https://doi.org/10.3390/antiox9050435 - 16 May 2020

Cited by 18 | Viewed by 3986

Abstract

Dehydroascorbate reductases (DHARs) are important enzymes that reconvert the dehydroascorbic acid (DHA) into ascorbic acid (ASC). They are involved in the plant response to oxidative stress, such as that induced by the mycotoxin beauvericin (BEA). Tomato plants were treated with 50 µM of [...] Read more.

Dehydroascorbate reductases (DHARs) are important enzymes that reconvert the dehydroascorbic acid (DHA) into ascorbic acid (ASC). They are involved in the plant response to oxidative stress, such as that induced by the mycotoxin beauvericin (BEA). Tomato plants were treated with 50 µM of BEA; the main antioxidant compounds and enzymes were evaluated. DHARs were analyzed in the presence of different electron donors by native and denaturing electrophoresis as well as by western blot and mass spectrometry to identify a novel induced protein with DHAR activity. Kinetic parameters for dehydroascorbate (DHA) and glutathione (GSH) were also determined. The novel DHAR was induced after BEA treatment. It was GSH-dependent and possessed lower affinity to DHA and GSH than the classical DHARs. Interestingly, the mass spectrometry analysis of the main band appearing on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed a chloroplast sedoheptulose 1,7-bisphosphatase, a key enzyme of the Calvin cycle, and a chloroplast mRNA-binding protein, suggesting that the DHA reducing capacity could be a side activity or the novel DHAR could be part of a protein complex. These results shed new light on the ascorbate-glutathione regulation network under oxidative stress and may represent a new way to increase the plant antioxidant defense system, plant nutraceutical value, and the health benefits of plant consumption. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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21 pages, 2223 KiB

Open AccessArticle

Multi-Component Antioxidative System and Robust Carbohydrate Status, the Essence of Plant Arsenic Tolerance

by Monika Kofroňová, Aneta Hrdinová, Petra Mašková, Jana Tremlová, Petr Soudek, Šárka Petrová, Dominik Pinkas and Helena Lipavská

Antioxidants 2020, 9(4), 283; https://doi.org/10.3390/antiox9040283 - 27 Mar 2020

Cited by 38 | Viewed by 3753

Abstract

Arsenic (As) contaminates the food chain and decreases agricultural production through impairing plants, particularly due to oxidative stress. To better understand the As tolerance mechanisms, two contrasting tobacco genotypes: As-sensitive Nicotiana sylvestris and As-tolerant N.tabacum, cv. ‘Wisconsin’ were analyzed. The most meaningful [...] Read more.

Arsenic (As) contaminates the food chain and decreases agricultural production through impairing plants, particularly due to oxidative stress. To better understand the As tolerance mechanisms, two contrasting tobacco genotypes: As-sensitive Nicotiana sylvestris and As-tolerant N.tabacum, cv. ‘Wisconsin’ were analyzed. The most meaningful differences were found in the carbohydrate status, neglected so far in the As context. In the tolerant genotype, contrary to the sensitive one, net photosynthesis rates and saccharide levels were unaffected by As exposure. Importantly, the total antioxidant capacity was far stronger in the As-tolerant genotype, based on higher antioxidants levels (e.g., phenolics, ascorbate, glutathione) and activities and/or appropriate localizations of antioxidative enzymes, manifested as reverse root/shoot activities in the selected genotypes. Accordingly, malondialdehyde levels, a lipid peroxidation marker, increased only in sensitive tobacco, indicating efficient membrane protection in As-tolerant species. We bring new evidence of the orchestrated action of a broad spectrum of both antioxidant enzymes and molecules essential for As stress coping. For the first time, we propose robust carbohydrate metabolism based on undisturbed photosynthesis to be crucial not only for subsidizing C and energy for defense but also for participating in direct reactive oxygen species (ROS) quenching. The collected data and suggestions can serve as a basis for the selection of plant As phytoremediators or for targeted breeding of tolerant crops. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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19 pages, 3999 KiB

Open AccessArticle

Global Evolutionary Analysis of 11 Gene Families Part of Reactive Oxygen Species (ROS) Gene Network in Four Eucalyptus Species

by Qiang Li, Hélène San Clemente, Yongrui He, Yongyao Fu and Christophe Dunand

Antioxidants 2020, 9(3), 257; https://doi.org/10.3390/antiox9030257 - 21 Mar 2020

Cited by 6 | Viewed by 3303

Abstract

Eucalyptus is a worldwide hard-wood species which increasingly focused on. To adapt to various biotic and abiotic stresses, Eucalyptus have evolved complex mechanisms, increasing the cellular concentration of reactive oxygen species (ROS) by numerous ROS controlling enzymes. To better analyse the ROS gene [...] Read more.

Eucalyptus is a worldwide hard-wood species which increasingly focused on. To adapt to various biotic and abiotic stresses, Eucalyptus have evolved complex mechanisms, increasing the cellular concentration of reactive oxygen species (ROS) by numerous ROS controlling enzymes. To better analyse the ROS gene network and discuss the differences between four Eucalyptus species, ROS gene network including 11 proteins families (1CysPrx, 2CysPrx, APx, APx-R, CIII Prx, Diox, GPx, Kat, PrxII, PrxQ and Rboh) were annotated and compared in an expert and exhaustive manner from the genomic data available from E. camaldulensis, E. globulus, E. grandis, and E. gunnii. In addition, a specific sequencing strategy was performed in order to determine if the missed sequences in at least one organism are the results of gain/loss events or only sequencing gaps. We observed that the automatic annotation applied to multigenic families is the source of miss-annotation. Base on the family size, the 11 families can be categorized into duplicated gene families (CIII Prx, Kat, 1CysPrx, and GPx), which contain a lot of gene duplication events and non-duplicated families (APx, APx-R, Rboh, DiOx, 2CysPrx, PrxII, and PrxQ). The gene family sizes are much larger in Eucalyptus than most of other angiosperms due to recent gene duplications, which could give higher adaptability to environmental changes and stresses. The cross-species comparative analysis shows gene gain and loss events during the evolutionary process. The 11 families possess different expression patterns, while in the Eucalyptus genus, the ROS families present similar expression patterns. Overall, the comparative analysis might be a good criterion to evaluate the adaptation of different species with different characters, but only if data mining is as exhaustive as possible. It is also a good indicator to explore the evolutionary process. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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20 pages, 2993 KiB

Open AccessArticle

Some Physiological and Biochemical Mechanisms during Seed-to-Seedling Transition in Tomato as Influenced by Garlic Allelochemicals

by Sikandar Hayat, Husain Ahmad, Mubasher Nasir, Muhammad Numan Khan, Muhammad Ali, Kashif Hayat, Muhammad Ali Khan, Farmanullah Khan, Yongqing Ma and Zhihui Cheng

Antioxidants 2020, 9(3), 235; https://doi.org/10.3390/antiox9030235 - 12 Mar 2020

Cited by 20 | Viewed by 4802

Abstract

The effects of aqueous garlic extracts (AGEs), diallyl disulfide (DADS), and allicin (AAS) were investigated during seed-to-seedling transition of tomato. Independent bioassays were performed including seed priming with AGE (0, 100, and 200 µg∙mL⁻¹), germination under the allelochemical influence of AGE, [...] Read more.

The effects of aqueous garlic extracts (AGEs), diallyl disulfide (DADS), and allicin (AAS) were investigated during seed-to-seedling transition of tomato. Independent bioassays were performed including seed priming with AGE (0, 100, and 200 µg∙mL⁻¹), germination under the allelochemical influence of AGE, DADS, and AAS, and germination under volatile application of AGE. Noticeable differences in germination indices and seedling growth (particularly root growth and fresh weights) were observed in a dose-dependent manner. When germinated under 50 mM NaCl, seeds primed with AGE exhibited induced defense via antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), lipid peroxidation (malondialdehyde content (MDA)), and H₂O₂ scavenging. Enzyme-linked immunosorbent analysis (ELISA) of the endogenous phytohormones auxin (IAA), abscisic acid (ABA), cytokinin (ZR), and gibberellic acid (GA₃) in the roots and shoots of the obtained seedlings and the relative expression levels of auxin-responsive protein (IAA2), like-auxin (LAX5), mitogen-activated protein kinase (MAPK7 and MPK2), respiratory burst oxidase homolog (RBOH1), CHI3 and SODCC1 suggested allelopathic functions in stimulating growth responses. Our findings suggest that garlic allelochemicals act as plant biostimulants to enhance auxin biosynthesis and transportation, resulting in root growth promotion. Additionally, the relative expressions of defense-related genes, antioxidant enzymes activities and phytohormonal regulations indicate activation of the defense responses in tomato seedlings resulting in better growth and development. These results, thus, provide a basis to understand the biological functions of garlic allelochemicals from the induced resistance perspective in plants. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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17 pages, 1682 KiB

Open AccessArticle

Melatonin Mitigates Chilling-Induced Oxidative Stress and Photosynthesis Inhibition in Tomato Plants

by Meiling Wang, Shuoxin Zhang and Fei Ding

Antioxidants 2020, 9(3), 218; https://doi.org/10.3390/antiox9030218 - 6 Mar 2020

Cited by 96 | Viewed by 4916

Abstract

Melatonin has been demonstrated to play a variety of roles in plants. Of particular importance is its role as a potent antioxidative agent. In the present study, we generated melatonin-deficient tomato plants using virus-induced gene silencing (VIGS) approach and melatonin-rich tomato plants by [...] Read more.

Melatonin has been demonstrated to play a variety of roles in plants. Of particular importance is its role as a potent antioxidative agent. In the present study, we generated melatonin-deficient tomato plants using virus-induced gene silencing (VIGS) approach and melatonin-rich tomato plants by foliar application of melatonin. These tomato plants were used to assess the effect of melatonin on chilling-induced oxidative stress and chilling-induced photosynthesis inhibition. We found that melatonin deficiency increased accumulation of reactive oxygen species (ROS) and aggravated lipid peroxidation in chilling-stressed tomato leaves, while exogenous application of melatonin had the opposite effect. Under chilling stress, melatonin-deficient tomato plants showed impaired antioxidant capacity as evidenced by lower activities of antioxidant enzymes and decreased rations of reduced glutathione (GSH)/oxidized glutathione (GSSG) and reduced ascorbate (AsA)/oxidized ascorbate (DHA), compared with melatonin-rich tomato plants. Furthermore, suppression of melatonin biosynthesis led to more photosynthesis inhibition under the chilling condition and compromised the capability of subsequent photosynthesis recovery in tomato plants. In addition, melatonin-deficient tomato plants displayed less activity of an important Calvin-Benson cycle enzyme sedoheptulose-1,7-bisphosphatase (SBPase) than melatonin-rich tomato plants under chilling stress. Collectively, our data indicate that melatonin is critical for antioxidant capacity and redox balance and is in favor of photosynthesis in tomato plants under chilling stress. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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19 pages, 1557 KiB

Open AccessArticle

Beneficial Impact of an Extract from the Berries of Aronia melanocarpa L. on the Oxidative-Reductive Status of the Submandibular Gland of Rats Exposed to Cadmium

by Adam Dąbrowski, Barbara M. Onopiuk, Halina Car, Paweł Onopiuk, Zofia N. Dąbrowska, Joanna Rogalska, Małgorzata M. Brzóska and Ewa Dąbrowska

Antioxidants 2020, 9(2), 185; https://doi.org/10.3390/antiox9020185 - 22 Feb 2020

Cited by 11 | Viewed by 4836

Abstract

Oxidative stress underlies the pathomechanisms of toxic action of cadmium (Cd), including its damaging impact on the oral cavity. This study investigated whether the administration of an extract from Aronia melanocarpa L. berries (AME), characterized by their strong antioxidative potential, may have a [...] Read more.

Oxidative stress underlies the pathomechanisms of toxic action of cadmium (Cd), including its damaging impact on the oral cavity. This study investigated whether the administration of an extract from Aronia melanocarpa L. berries (AME), characterized by their strong antioxidative potential, may have a beneficial impact on the oxidative-reductive status of the submandibular gland in an experimental model of low-level and moderate human environmental exposure to cadmium. The main markers of the antioxidative status (glutathione reductase, superoxide dismutase, catalase, reduced glutathione, total antioxidative status (TAS)), total oxidative status (TOS), oxidative stress index (OSI = TOS/TAS), and lipid peroxides, as well as cadmium concentration, were evaluated in the submandibular gland tissue of female Wistar rats who received a 0.1% aqueous AME and/or a diet containing 0, 1, and 5 mg Cd/kg for 3 and 10 months. The treatment with cadmium decreased the activities of antioxidative enzymes (29%–74%), reduced glutathione concentration (45%–52%), and TAS and increased TOS, resulting in the development of oxidative stress and enhanced concentration of lipid peroxides in the submandibular gland. The administration of AME at both levels of exposure to cadmium offered significant protection against these actions of this xenobiotic. After the 10 month exposure to the 1 and 5 mg Cd/kg diet, TAS was decreased by 77% and 83%, respectively, TOS, OSI, and lipid peroxides concentration were increased by 50% and 52%, respectively, 11.8-fold and 14.4-fold, respectively, and 2.3-fold and 4.3-fold, respectively, whereas, in the case of the extract co-administration, the values of these parameters did not differ compared to the control group. The results indicate that the consumption of aronia products under exposure to cadmium may have a beneficial impact on the oxidative-reductive status of the submandibular gland and prevent oxidative stress development and enhanced lipid peroxidation in this salivary gland. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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30 pages, 5791 KiB

Open AccessArticle

Ecotype-Specific Pathways of Reactive Oxygen Species Deactivation in Facultative Metallophyte Silene vulgaris (Moench) Garcke Treated with Heavy Metals

by Ewa Muszyńska, Mateusz Labudda and Adam Kral

Antioxidants 2020, 9(2), 102; https://doi.org/10.3390/antiox9020102 - 24 Jan 2020

Cited by 16 | Viewed by 2827

Abstract

This research aimed to indicate mechanisms involved in protection against the imbalanced generation of reactive oxygen species (ROS) during heavy metals (HMs) exposition of Silene vulgaris ecotypes with different levels of metal tolerance. Specimens of non-metallicolous (NM), calamine (CAL), and serpentine (SER) ecotypes [...] Read more.

This research aimed to indicate mechanisms involved in protection against the imbalanced generation of reactive oxygen species (ROS) during heavy metals (HMs) exposition of Silene vulgaris ecotypes with different levels of metal tolerance. Specimens of non-metallicolous (NM), calamine (CAL), and serpentine (SER) ecotypes were treated in vitro with Zn, Pb, and Cd ions applied simultaneously in concentrations that reflected their contents in natural habitats of the CAL ecotype (1× HMs) and 2.5- or 5.0-times higher than the first one. Our findings confirmed the sensitivity of the NM ecotype and revealed that the SER ecotype was not fully adapted to the HM mixture, since intensified lipid peroxidation, ultrastructural alternations, and decline in photosynthetic pigments’ content were ascertained under HM treatment. These changes resulted from insufficient antioxidant defense mechanisms based only on ascorbate peroxidase (APX) activity assisted (depending on HMs concentration) by glutathione-S-transferase (GST) and peroxidase activity at pH 6.8 in the NM ecotype or by GST and guaiacol-type peroxidase in the SER one. In turn, CAL specimens showed a hormetic reaction to 1× HMs, which manifested by both increased accumulation of pigments and most non-enzymatic antioxidants and enhanced activity of catalase and enzymes from the peroxidase family (with the exception of APX). Interestingly, no changes in superoxide dismutase activity were noticed in metallicolous ecotypes. To sum up, the ROS scavenging pathways in S. vulgaris relied on antioxidants specific to the respective ecotypes, however the synthesis of polyphenols was proved to be a universal reaction to HMs. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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Review

Jump to: Editorial, Research

22 pages, 7296 KiB

Open AccessFeature PaperReview

The Pivotal Role of Adipocyte-Na K peptide in Reversing Systemic Inflammation in Obesity and COVID-19 in the Development of Heart Failure

by Zi-jian Xie, Joel Novograd, Yaakov Itzkowitz, Ariel Sher, Yosef D. Buchen, Komal Sodhi, Nader G. Abraham and Joseph I. Shapiro

Antioxidants 2020, 9(11), 1129; https://doi.org/10.3390/antiox9111129 - 14 Nov 2020

Cited by 7 | Viewed by 4110

Abstract

This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms [...] Read more.

This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms an oxidant amplification loop (NKAL), amplifies ROS, and participates in cytokines storm in obesity. The development of a peptide fragment of the α1 subunit, NaKtide, has been shown to negatively regulate Src. Several groups showed that the systemic administration of the cell permeable modification of NaKtide (pNaKtide) or its selective delivery to fat tissue—adipocyte specific expression of NaKtide—ameliorate the systemic elevation of inflammatory cytokines seen in chronic obesity. Severe acute respiratory syndrome – coronavirus 2 (SARS-CoV-2), the RNA Coronavirus responsible for the COVID-19 global pandemic, invades cells via the angiotensin converting enzyme 2 (ACE-2) receptor (ACE2R) that is appended in inflamed fat tissue and exacerbates the formation of the cytokines storm. Both obesity and heart and renal failure are well known risks for adverse outcomes in patients infected with COVID-19. White adipocytes express ACE-2 receptors in high concentration, especially in obese patients. Once the virus invades the white adipocyte cell, it creates a COVID19–porphyrin complex which degrades and produces free porphyrin and iron and increases ROS. The increased formation of ROS and activation of the NKAL results in a further potentiated formation of ROS production, and ultimately, adipocyte generation of more inflammatory mediators, leading to systemic cytokines storm and heart failure. Moreover, chronic obesity also results in the reduction of antioxidant genes such as heme oxygenase-1 (HO-1), increasing adipocyte susceptibility to ROS and cytokines. It is the systemic inflammation and cytokine storm which is responsible for many of the adverse outcomes seen with COVID-19 infections in obese subjects, leading to heart failure and death. This review will also describe the potential antioxidant drugs and role of NaKtide and their demonstrated antioxidant effect used as a major strategy for improving obesity and epicardial fat mediated heart failure in the context of the COVID pandemic. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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28 pages, 4038 KiB

Open AccessReview

The Universal Soldier: Enzymatic and Non-Enzymatic Antioxidant Functions of Serum Albumin

by Daria A. Belinskaia, Polina A. Voronina, Vladimir I. Shmurak, Mikhail A. Vovk, Anastasia A. Batalova, Richard O. Jenkins and Nikolay V. Goncharov

Antioxidants 2020, 9(10), 966; https://doi.org/10.3390/antiox9100966 - 9 Oct 2020

Cited by 59 | Viewed by 5707

Abstract

As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in [...] Read more.

As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in the literature and from our own research on the mechanisms of the enzymatic and non-enzymatic activities of albumin that determine its participation in redox modulation of plasma and intercellular fluid. For the first time, the results of numerous clinical, biochemical, spectroscopic and computational experiments devoted to the study of allosteric modulation of the functional properties of the protein associated with its participation in antioxidant defence are analysed. It has been concluded that it is fundamentally possible to regulate the antioxidant properties of albumin with various ligands, and the binding and/or enzymatic features of the protein by changing its redox status. The perspectives for using the antioxidant properties of albumin in practice are discussed. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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14 pages, 812 KiB

Open AccessReview

Copper Sources for Sod1 Activation

by Stefanie D. Boyd, Morgan S. Ullrich, Amelie Skopp and Duane D. Winkler

Antioxidants 2020, 9(6), 500; https://doi.org/10.3390/antiox9060500 - 7 Jun 2020

Cited by 33 | Viewed by 4756

Abstract

Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the [...] Read more.

Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the accumulation of radical oxygen species by way of the redox cycling activity of copper in its catalytic center. Multiple posttranslational modification events, including copper incorporation, are reliant on the copper chaperone for Sod1 (Ccs). The high-affinity copper uptake protein (Ctr1) is the main entry point of copper into eukaryotic cells and can directly supply copper to Ccs along with other known intracellular chaperones and trafficking molecules. This review explores the routes of copper delivery that are utilized to activate Sod1 and the usefulness and necessity of each. Full article

(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

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