Research of corrosion fracture of D16t and AMg6 aluminum alloys exposed to microscopic fungi

2021 ◽  
pp. 163-183
Author(s):  
D. V. Belov ◽  
S. N. Belyaev ◽  
M. V. Maksimov ◽  
G. A. Gevorgyan
Keyword(s):  
Hydrogen Peroxide ◽  
Aluminum Alloys ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Corrosion Damage ◽  
Oxygen Species ◽  
Microscopic Fungi ◽  
Reductive Activation ◽  
Activation Of Oxygen

This paper presents an experimental study of biocorrosion of D16T and AMg6 aluminum alloys. The determining role of reactive oxygen species in aluminum biocorrosion by a consortium of molds has been shown. A model is proposed, according to which the initiators of corrosion damage to the metal surface are superoxide anion radical and hydrogen peroxide released during the life of micromycetes. It is assumed that the initiation and development of biocorrosion occurs, among other things, as a result of the process of reductive activation of oxygen and the Fenton decomposition of hydrogen peroxide. A conclusion is made about the mechanism of the occurrence of intergranular and pitting corrosion of aluminum alloys interacting with microscopic fungi.

scholarly journals A Novel Tetrapeptide Derivative Exhibits In Vitro Inhibition of Neutrophil-Derived Reactive Oxygen Species and Lysosomal Enzymes Release

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Sumitra Miriyala ◽  
Manikandan Panchatcharam ◽  
Meera Ramanujam ◽  
Rengarajulu Puvanakrishnan
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Anion ◽  
Lysosomal Enzymes ◽  
Reactive Oxygen ◽  
Peptide Sequence ◽  
Ros Generation ◽  
Oxygen Species ◽  
Complement Factors

Neutrophil infiltration plays a major role in the pathogenesis of myocardial injury. Oxidative injury is suggested to be a central mechanism of the cellular damage after acute myocardial infarction. This study is pertained to the prognostic role of a tetrapeptide derivative PEP1261 (BOC-Lys(BOC)-Arg-Asp-Ser(tBu)-OtBU), a peptide sequence (39–42) of lactoferrin, studied in the modulation of neutrophil functions in vitro by measuring the reactive oxygen species (ROS) generation, lysosomal enzymes release, and enhanced expression of C proteins. The groundwork experimentation was concerned with the isolation of neutrophils from the normal and acute myocardial infarct rats to find out the efficacy of PEP1261 in the presence of a powerful neutrophil stimulant, phorbol 12-myristate 13 acetate (PMA). Stimulation of neutrophils with PMA resulted in an oxidative burst of superoxide anion and enhanced release of lysosomal enzymes and expression of complement proteins. The present study further demonstrated that the free radicals increase the complement factors in the neutrophils confirming the role of ROS. PEP1261 treatment significantly reduced the levels of superoxide anion and inhibited the release of lysosomal enzymes in the stimulated control and infarct rat neutrophils. This study demonstrated that PEP1261 significantly inhibited the effect on the ROS generation as well as the mRNA synthesis and expression of the complement factors in neutrophils isolated from infarct heart.

scholarly journals Glutathione Participation in the Prevention of Cardiovascular Diseases

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1220
Author(s):  
Deyamira Matuz-Mares ◽  
Héctor Riveros-Rosas ◽  
María Magdalena Vilchis-Landeros ◽  
Héctor Vázquez-Meza
Keyword(s):  
Cardiovascular Diseases ◽  
Superoxide Anion ◽  
Reactive Nitrogen Species ◽  
Hypochlorous Acid ◽  
Reduced Glutathione ◽  
Heart Diseases ◽  
Reactive Species ◽  
Oxygen Species ◽  
Cardiovascular Pathologies

Cardiovascular diseases (CVD) (such as occlusion of the coronary arteries, hypertensive heart diseases and strokes) are diseases that generate thousands of patients with a high mortality rate worldwide. Many of these cardiovascular pathologies, during their development, generate a state of oxidative stress that leads to a deterioration in the patient’s conditions associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Within these reactive species we find superoxide anion (O2•–), hydroxyl radical (•OH), nitric oxide (NO•), as well as other species of non-free radicals such as hydrogen peroxide (H2O2), hypochlorous acid (HClO) and peroxynitrite (ONOO–). A molecule that actively participates in counteracting the oxidizing effect of reactive species is reduced glutathione (GSH), a tripeptide that is present in all tissues and that its synthesis and/or regeneration is very important to be able to respond to the increase in oxidizing agents. In this review, we will address the role of glutathione, its synthesis in both the heart and the liver, and its importance in preventing or reducing deleterious ROS effects in cardiovascular diseases.

scholarly journals Peptide-Templated Gold Clusters as Enzyme-Like Catalyst Boost Intracellular Oxidative Pressure and Induce Tumor-Specific Cell Apoptosis

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1040 ◽  
Author(s):  
Ya Zhang ◽  
Xiangchun Zhang ◽  
Qing Yuan ◽  
Wenchao Niu ◽  
Chunyu Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Cell Apoptosis ◽  
Superoxide Anion ◽  
Reactive Oxygen ◽  
Gold Clusters ◽  
Specific Cell ◽  
Oxygen Species ◽  
Potential Damage

Anticancer metallodrugs that aim to physiological characters unique to tumor microenvironment are expected to combat drug tolerance and side-effects. Recently, owing to the fact that reactive oxygen species’ is closely related to the development of tumors, people are committed to developing metallodrugs with the capacity of improving the level of reactive oxygen species level toinduce oxidative stress in cancer cells. Herein, we demonstrated that peptide templated gold clusters with atomic precision preferably catalyze the transformation of hydrogen peroxide into superoxide anion in oxidative pressure-type tumor cells. Firstly, we successfully constructed gold clusters by rationally designing peptide sequences which targets integrin ανβ3 overexpressed on glioblastoma cells. The superoxide anion, radical derived from hydrogen peroxide and catalyzed by gold clusters, was confirmed in vitro under pseudo-physiological conditions. Then, kinetic parameters were evaluated to verify the catalytic properties of gold clusters. Furthermore, these peptide decorated clusters can serve as special enzyme-like catalyst to convert endogenous hydrogen peroxide into superoxide anion, elevated intracellular reactive oxygen species levels, lower mitochondrial membrane potential, damage biomacromolecules, and trigger tumor cell apoptosis consequently.

scholarly journals The Protective Role of 1,8-Dihydroxynaphthalene–Melanin on Conidia of the Opportunistic Human Pathogen Aspergillus fumigatus Revisited: No Role in Protection against Hydrogen Peroxide and Superoxides

mSphere ◽  
2022 ◽  
Author(s):  
E. M. Keizer ◽  
I. D. Valdes ◽  
B. L. McCann ◽  
E. M. Bignell ◽  
H. A. B. Wösten ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Aspergillus Fumigatus ◽  
Protective Role ◽  
Oxygen Species ◽  
Human Pathogen ◽  
Opportunistic Pathogens ◽  
Green Pigment ◽  
Content Type ◽  
Opportunistic Human Pathogen

Opportunistic pathogens like Aspergillus fumigatus have strategies to protect themselves against reactive oxygen species like hydrogen peroxides and superoxides that are produced by immune cells. DHN-melanin is the green pigment on conidia of Aspergillus fumigatus and more than 2 decades ago was reported to protect conidia against hydrogen peroxide.

scholarly journals Specificity of H2O2 signaling in leaf senescence: is the ratio of H2O2 contents in different cellular compartments sensed in Arabidopsis plants?

2022 ◽  
Vol 27 (1) ◽  
Author(s):  
Ulrike Zentgraf ◽  
Ana Gabriela Andrade-Galan ◽  
Stefan Bieker
Keyword(s):  
Hydrogen Peroxide ◽  
Leaf Senescence ◽  
Mineral Resources ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Differential Impact ◽  
Environmental Signals ◽  
Complex Process ◽  
Cellular Compartments

AbstractLeaf senescence is an integral part of plant development and is driven by endogenous cues such as leaf or plant age. Developmental senescence aims to maximize the usage of carbon, nitrogen and mineral resources for growth and/or for the sake of the next generation. This requires efficient reallocation of the resources out of the senescing tissue into developing parts of the plant such as new leaves, fruits and seeds. However, premature senescence can be induced by severe and long-lasting biotic or abiotic stress conditions. It serves as an exit strategy to guarantee offspring in an unfavorable environment but is often combined with a trade-off in seed number and quality. In order to coordinate the very complex process of developmental senescence with environmental signals, highly organized networks and regulatory cues have to be in place. Reactive oxygen species, especially hydrogen peroxide (H2O2), are involved in senescence as well as in stress signaling. Here, we want to summarize the role of H2O2 as a signaling molecule in leaf senescence and shed more light on how specificity in signaling might be achieved. Altered hydrogen peroxide contents in specific compartments revealed a differential impact of H2O2 produced in different compartments. Arabidopsis lines with lower H2O2 levels in chloroplasts and cytoplasm point to the possibility that not the actual contents but the ratio between the two different compartments is sensed by the plant cells.

Activated oxygen species do not mediate hypercapnia-induced cerebral vasodilation in newborn pigs

1991 ◽  
Vol 261 (2) ◽  
pp. H335-H342 ◽  
Author(s):  
C. W. Leffler ◽  
R. Mirro ◽  
C. Thompson ◽  
M. Shibata ◽  
W. M. Armstead ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Xanthine Oxidase ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Superoxide Anion Radical ◽  
Radical Scavenger ◽  
Oxygen Species ◽  
Pial Arteries ◽  
Activated Oxygen ◽  
Newborn Pigs

In newborn pigs, vasodilation in response to hypercapnia is dependent on prostaglandin (PG) H synthase. We investigated the contribution of activated oxygen by-products to hypercapnia-induced PGH synthase-dependent dilation of pial arteries and arterioles in anesthetized newborn pigs. Activated oxygen species were generated on the cerebral surface using xanthine oxidase and hypoxanthine. Catalase, H2O2, and iron or N-(2-mercaptopropionyl)-glycine (MPG) were used to separate effects of superoxide anion and hydroxyl radical. All the activated oxygen species tested caused vasodilation of both arteries and arterioles. Vasodilation to all activated oxygen species was largely reversible with only the hydroxyl radical encouraging combination of xanthine oxidase, hypoxanthine, H2O2, and FeCl3, causing significant dilation 20 min after removal of treatment. Cotreatment with MPG blocked this residual dilation. Neither pretreatment with the extracellular superoxide anion radical scavenger, superoxide dismutase (SOD), the intracellular superoxide anion radical scavenger, Tiron, the H2O2 scavenger, catalase, nor hydroxyl radical scavengers, dimethyl sulfoxide (DMSO) and MPG, altered vasodilation of pial arteries or arterioles in response to hypercapnia. Furthermore, the increase in cerebral prostanoid synthesis in response to hypercapnia was not affected by pretreatment with SOD, Tiron, catalase, DMSO, or MPG. We conclude that the progressively reduced forms of oxygen that would be produced during PGH synthase metabolism of arachidonic acid can dilate pial arteries and arterioles of newborn pigs. However, these activated oxygen species are not responsible for the vasodilation to hypercapnia in the newborn pig, suggesting that eicosanoids cause the dilation.

Role of reactive oxygen species-generating enzymes and hydrogen peroxide during cadmium, mercury and osmotic stresses in barley root tip

Planta ◽  
2009 ◽  
Vol 231 (2) ◽  
pp. 221-231 ◽  
Author(s):  
Ladislav Tamás ◽  
Igor Mistrík ◽  
Jana Huttová ◽  
L’ubica Halušková ◽  
Katarína Valentovičová ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Reactive Oxygen ◽  
Barley Root ◽  
Root Tip ◽  
Oxygen Species ◽  
Barley Root Tip

scholarly journals Dual Role of ROS as Signal and Stress Agents: Iron Tips the Balance in favor of Toxic Effects

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Elena Gammella ◽  
Stefania Recalcati ◽  
Gaetano Cairo
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Oxidative Damage ◽  
Cell Signaling ◽  
Hydroxyl Radical ◽  
Iron Homeostasis ◽  
Storage Proteins ◽  
Oxygen Species ◽  
Physiologic Role

Iron is essential for life, while also being potentially harmful. Therefore, its level is strictly monitored and complex pathways have evolved to keep iron safely bound to transport or storage proteins, thereby maintaining homeostasis at the cellular and systemic levels. These sequestration mechanisms ensure that mildly reactive oxygen species like anion superoxide and hydrogen peroxide, which are continuously generated in cells living under aerobic conditions, keep their physiologic role in cell signaling while escaping iron-catalyzed transformation in the highly toxic hydroxyl radical. In this review, we describe the multifaceted systems regulating cellular and body iron homeostasis and discuss how altered iron balance may lead to oxidative damage in some pathophysiological settings.

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