scholarly journals Can aluminum, a non-redox metal, alter the thermodynamics of key biological redox processes? The DPPH-QH 2 radical scavenging reaction as a test case.

2021 ◽  
Author(s):  
Jose Lanuza ◽  
Veronica Postils ◽  
Xabier Lopez
Keyword(s):  
Radical Scavenging ◽  
Test Case ◽  
Redox Processes ◽  
Oxygen Species ◽  
Redox Potentials ◽  
Oxidation Potentials ◽  
Living Organisms ◽  
Experimental Findings ◽  
First Time

The increased bioavailability of aluminum has led to a concern about its toxicity on living systems. Among the most important toxic effects, it has been proven that aluminum increases oxidative stress in biological systems, a controversial fact, however, due to its non-redox nature. In the present work, we characterize in detail how aluminum can alter redox equilibriums by analyzing its effects on the thermodynamics of the redox scavenging reaction between DPPH . , a radical compound often used as a reactive oxygen species model, and hydroquinones, a potent natural antioxidant. For the first time, theoretical and experimental redox potentials within aluminum biochemistry are directly compared. Our results fully agree with experimental reduction and oxidation potentials, unequivocally revealing how aluminum alters the spontaneity of the reaction by stabilizing the reduction of DPPH· to DPPH − and promoting a proton transfer to the diazine moiety, leading to the production of a DPPH-H species. The capability of aluminum to modify redox potentials shown here confirms previous experimental findings on the role of aluminum to interfere with free radical scavenging reactions, affecting the natural redox processes of living organisms.

scholarly journals The signalling role of ROS in the regulation of seed germination and dormancy

2019 ◽  
Vol 476 (20) ◽  
pp. 3019-3032 ◽  
Author(s):  
Christophe Bailly
Keyword(s):  
Seed Germination ◽  
Oxygen Species ◽  
Direct Oxidation ◽  
Cellular Events ◽  
Seed Physiology ◽  
Spatiotemporal Regulation ◽  
Wide Range ◽  
Living Organisms ◽  
Hormone Signalling

Abstract Reactive oxygen species (ROS) are versatile compounds which can have toxic or signalling effects in a wide range living organisms, including seeds. They have been reported to play a pivotal role in the regulation of seed germination and dormancy but their mechanisms of action are still far from being fully understood. In this review, we sum-up the major findings that have been carried out this last decade in this field of research and which altogether shed a new light on the signalling roles of ROS in seed physiology. ROS participate in dormancy release during seed dry storage through the direct oxidation of a subset of biomolecules. During seed imbibition, the controlled generation of ROS is involved in the perception and transduction of environmental conditions that control germination. When these conditions are permissive for germination, ROS levels are maintained at a level which triggers cellular events associated with germination, such as hormone signalling. Here we propose that the spatiotemporal regulation of ROS production acts in concert with hormone signalling to regulate the cellular events involved in cell expansion associated with germination.

The role of various oxygen species in Mn-based layered double hydroxide catalysts in selective alcohol oxidation

2017 ◽  
Vol 7 (19) ◽  
pp. 4361-4365 ◽  
Author(s):  
Yiyun Du ◽  
Qian Wang ◽  
Xiao Liang ◽  
Pengfei Yang ◽  
Yufei He ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Alcohol Oxidation ◽  
Oxygen Species ◽  
Precise Identification ◽  
Double Hydroxide ◽  
First Time

Precise identification of oxygen species in LDH-based catalysts was investigated for the first time for alcohol oxidation.

scholarly journals Quinones and hydroxyquinones as generators and quenchers of singlet molecular oxygen

1997 ◽  
Vol 75 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Isela Gutiérrez ◽  
Sonia G. Bertolotti ◽  
M.A. Biasutti ◽  
Arnaldo T. Soltermann ◽  
Norman A. García
Keyword(s):  
Oxygen Species ◽  
Type Ii ◽  
Carbonyl Groups ◽  
Quenching Mechanism ◽  
Singlet Molecular Oxygen ◽  
Dye Sensitized ◽  
Quenching Process ◽  
First Time ◽  
Excited Oxygen

The role of quinones and hydroxyquinones as sensitizers and as quenchers in Type II photooxygenations has been examined. The second aspect is discussed here, through a systematic study, for the first time in the open literature. Quinonic compounds are excellent generators of O2(1Δg) in aprotic solvents (excluding those quinones possessing substituents in positions adjacent to the carbonyl groups, in the case of anthraquinone derivatives). Benzoquinones, anthraquinones, and hydroxy derivatives are good O2(1Δg) quenchers upon dye-sensitized photoirradiation. The excited oxygen species is deactivated with rate constants in the range 106–107 M−1 s−1 depending on the solvent employed. The quenching process deactivates O2(1Δg) without further destruction of the quinone. The main interaction with O2(1Δg) is driven by the quinone moiety, in spite of the presence of potentially active nuclear substituents. The quenching mechanism could involve a reversible charge transfer intermediate, with the quinonic compound acting as an electron donor. Keywords: photooxidation, quenching, quinones, rose bengal, singlet oxygen.

Parvalbumin is overexpressed in the late phase of pharmacological preconditioning in skeletal muscle

2013 ◽  
Vol 91 (11) ◽  
pp. 966-972
Author(s):  
Rosario Solis ◽  
Elba D. Carrillo ◽  
Ascención Hernández ◽  
María C. García ◽  
Jorge A. Sánchez
Keyword(s):  
Skeletal Muscle ◽  
Adult Mouse ◽  
Late Phase ◽  
Oxygen Species ◽  
Partial Protection ◽  
Intracellular Ca ◽  
Ros Scavenger ◽  
First Time ◽  
Pharmacological Preconditioning

Pharmacological preconditioning (PPC) with mitochondrial ATP-sensitive K+ channel openers such as diazoxide, provides protection against ischemia in cardiac muscle, skeletal muscle, and other tissues. Effects on Ca2+ homeostasis during the late phase of PPC have been described in cardiomyocytes, but no information is available regarding intracellular Ca2+ changes in skeletal muscle fibers during late PPC. Intracellular Ca2+ signals were measured in single fibers of adult mouse skeletal muscle, with fluorescent probes, 48 h after the administration of diazoxide. Parvalbumin levels in the myofibers were quantitated by Western blot. Diazoxide induction of late PPC was confirmed by partial protection of muscles from peroxide-induced damage. Late PPC was associated with a significant decrease in the duration of Ca2+ signals during single twitches and tetanus with no changes in peak values. This effect was prevented by the reactive oxygen species (ROS) scavenger tiron. Late PPC was accompanied by a 30% increase in parvalbumin levels, and this effect was also blocked by tiron. Our data show, for the first time, a role of parvalbumin in late PPC in skeletal muscle.

scholarly journals Trehalose and trehalose-6-phosphate induce stomatal movements and interfere with ABA-induced stomatal closure in grapevine

OENO One ◽  
2015 ◽  
Vol 49 (3) ◽  
pp. 165 ◽  
Author(s):  
Magdalena Gamm ◽  
Marie-Claire Héloir ◽  
Marielle Adrian
Keyword(s):  
Stomatal Closure ◽  
Guard Cells ◽  
Oxygen Species ◽  
Light Conditions ◽  
Whole Plant ◽  
Low Concentrations ◽  
Stomatal Movements ◽  
Plant Level ◽  
First Time

<p style="text-align: justify;"><strong>Aims</strong>: The effects of trehalose and trehalose-6-phosphate (T6P), among other sugars, were assessed on grapevine stomatal movements.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Epidermal peels were used to assess the effects of sugars. Low concentrations of trehalose and T6P (1 µM) induced an osmotic-independent reduction of the stomatal aperture in light conditions. Furthermore, ABA-induced stomatal closure was reduced by sugar application in association with lower accumulation of reactive oxygen species in guard cells. Similar effects, although weaker, were observed in response to the disaccharides sucrose and maltose, but not in response to the monosaccharides fructose and glucose.</p><p style="text-align: justify;"><strong>Conclusion</strong>: This study clearly highlights the effects of sugars, especially trehalose and T6P, on grapevine stomatal movements.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This is the first time that such effects are described in grapevine and the results obtained provide new insights about the role of sugars on stomatal regulation at the whole plant level.</p>

scholarly journals Intracellular Redox-Balance Involvement in Temozolomide Resistance-Related Molecular Mechanisms in Glioblastoma

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1315 ◽  
Author(s):  
Alessia Lo Dico ◽  
Daniela Salvatore ◽  
Cristina Martelli ◽  
Dario Ronchi ◽  
Cecilia Diceglie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanisms ◽  
Redox Balance ◽  
Oxygen Species ◽  
Cytotoxic Effects ◽  
Mitochondrial Ros ◽  
Resistance Fluctuations ◽  
First Time ◽  
Chaperone Mediated Autophagy

Glioblastoma (GBM) is the most common astrocytic-derived brain tumor in adults, characterized by a poor prognosis mainly due to the resistance to the available therapy. The study of mitochondria-derived oxidative stress, and of the biological events that orbit around it, might help in the comprehension of the molecular mechanisms at the base of GBM responsiveness to Temozolomide (TMZ). Sensitive and resistant GBM cells were used to test the role of mitochondrial ROS release in TMZ-resistance. Chaperone-Mediated Autophagy (CMA) activation in relation to reactive oxygen species (ROS) release has been measured by monitoring the expression of specific genes. Treatments with H2O2 were used to test their potential in reverting resistance. Fluctuations of cytoplasmic ROS levels were accountable for CMA induction and cytotoxic effects observed in TMZ sensitive cells after treatment. On the other hand, in resistant cells, TMZ failed in producing an increase in cytoplasmic ROS levels and CMA activation, preventing GBM cell toxicity. By increasing oxidative stress, CMA activation was recovered, as also cell cytotoxicity, especially in combination with TMZ treatment. Herein, for the first time, it is shown the relation between mitochondrial ROS release, CMA activation and TMZ-responsiveness in GBM.

scholarly journals Metallothionein 3 Promotes Osteoblast Differentiation in C2C12 Cells via Reduction of Oxidative Stress

2021 ◽  
Vol 22 (9) ◽  
pp. 4312
Author(s):  
Santie Li ◽  
Myeong-Ji Kim ◽  
Sung-Ho Lee ◽  
Litai Jin ◽  
Weitao Cong ◽  
...  
Keyword(s):  
Osteoblast Differentiation ◽  
Redox Balance ◽  
C2c12 Cells ◽  
Antimycin A ◽  
Ros Production ◽  
Oxygen Species ◽  
C2c12 Myoblasts ◽  
Morphogenetic Protein ◽  
Living Organisms

Metallothioneins (MTs) are intracellular cysteine-rich proteins, and their expressions are enhanced under stress conditions. MTs are recognized as having the ability to regulate redox balance in living organisms; however, their role in regulating osteoblast differentiation is still unclear. In this research, we found that the expression of MT3, one member of the MT protein family, was specifically upregulated in the differentiation process of C2C12 myoblasts treated with bone morphogenetic protein 4 (BMP4). Transfection with MT3-overexpressing plasmids in C2C12 cells enhanced their differentiation to osteoblasts, together with upregulating the protein expression of bone specific transcription factors runt-related gene 2 (Runx2), Osterix, and distal-less homeobox 5 (Dlx5). Additionally, MT3 knockdown performed the opposite. Further studies revealed that overexpression of MT3 decreased reactive oxygen species (ROS) production in C2C12 cells treated with BMP4, and MT3 silencing enhanced ROS production. Treating C2C12 cells with antioxidant N-acetylcysteine also promoted osteoblast differentiation, and upregulated Runx2/Osterix/Dlx5, while ROS generator antimycin A treatment performed the opposite. Finally, antimycin A treatment inhibited osteoblast differentiation and Runx2/Osterix/Dlx5 expression in MT3-overexpressing C2C12 cells. These findings identify the role of MT3 in osteoblast differentiation and indicate that MT3 may have interesting potential in the field of osteogenesis research.

scholarly journals Co-Occurrence and Combinatory Effects of Alternaria Mycotoxins and other Xenobiotics of Food Origin: Current Scenario and Future Perspectives

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 640 ◽  
Author(s):  
Crudo ◽  
Varga ◽  
Aichinger ◽  
Galaverna ◽  
Marko ◽  
...  
Keyword(s):  
Low Molecular Weight ◽  
Chemical Mixtures ◽  
Simultaneous Exposure ◽  
Contaminated Food ◽  
Food And Feed ◽  
Current Scenario ◽  
Alternaria Mycotoxins ◽  
Living Organisms ◽  
First Time

Mycotoxins are low-molecular weight compounds produced by diverse genera of molds that may contaminate food and feed threatening the health of humans and animals. Recent findings underline the importance of studying the combined occurrence of multiple mycotoxins and the relevance of assessing the toxicity their simultaneous exposure may cause in living organisms. In this context, for the first time, this work has critically reviewed the most relevant data concerning the occurrence and toxicity of mycotoxins produced by Alternaria spp., which are among the most important emerging risks to be assessed in food safety, alone or in combination with other mycotoxins and bioactive food constituents. According to the literature covered, multiple Alternaria mycotoxins may often occur simultaneously in contaminated food, along with several other mycotoxins and food bioactives inherently present in the studied matrices. Although the toxicity of combinations naturally found in food has been rarely assessed experimentally, the data collected so far, clearly point out that chemical mixtures may differ in their toxicity compared to the effect of toxins tested individually. The data presented here may provide a solid foothold to better support the risk assessment of Alternaria mycotoxins highlighting the actual role of chemical mixtures on influencing their toxicity.

scholarly journals Emergence and diversification of a host-parasite RNA ecosystem through Darwinian evolution

2019 ◽  
Author(s):  
Taro Furubayashi ◽  
Kensuke Ueda ◽  
Yohsuke Bansho ◽  
Daisuke Motooka ◽  
Shota Nakamura ◽  
...  
Keyword(s):  
Darwinian Evolution ◽  
Prebiotic Evolution ◽  
Clonal Population ◽  
Replication Errors ◽  
Replication Experiment ◽  
Living Organisms ◽  
Host Parasite ◽  
First Time

AbstractIn the prebiotic evolution, molecular self-replicators are considered to develop into diverse, complex living organisms. The appearance of parasitic replicators is believed inevitable in this process. However, the role of parasitic replicators on prebiotic evolution remains elusive. Here, we demonstrated experimental coevolution of RNA self-replicators (host RNAs) and emerging parasitic replicators (parasitic RNAs) for the first time by using an RNA-protein replication system we had developed. During a long-term replication experiment, a clonal population of the host RNA turned into an evolving host-parasite ecosystem through the continuous emergence of new types of host and parasitic RNAs produced by replication errors. The diversified host and parasitic RNAs exhibited evolutionary arms-race dynamics. The parasitic RNA accumulated unique mutations that the host RNA had never acquired, thus adding a new genetic variation to the whole replicator ensemble. These results provide the first experimental evidence that the coevolutionary interplay between host-parasite molecules play a key role in generating diversity and complexity in prebiotic molecular evolution.

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